WO2024038526A1 - Prescribed light generation method, optical characteristics modification unit, light source, prescribed light usage method, detection method, imaging method, display method, optical measurement unit, optical apparatus, service provision method, and service provision system - Google Patents

Abstract

The present invention causes the same light emission unit to radiate first light and second light through a prescribed optical member such that: an incident surface-side perpendicular line orthogonal to the incident surface of the prescribed optical member is defined; the travel direction of the first light has an inclination angle with respect to the incident surface-side perpendicular line; and the travel direction of the second light is set to be inclined with respect to the travel direction of the first light or the optical path of the second light and the optical path of the first light are set to be different inside the prescribed optical member to modify optical characteristics between the first light and the second light.

Description

Predetermined light generation method, optical property changing unit, light source, predetermined light utilization method, detection method, imaging method, display method, optical measurement unit, optical device, service provision method, service provision system

This embodiment relates to the technical field of controlling the characteristics of light itself, the field of measurement using light, the field of utilizing light, or the field of providing services using light.

The characteristics of light itself are not limited to wavelength characteristics, intensity distribution characteristics, and phase distribution characteristics (including wave front characteristics), but also have various attributes such as directivity and coherence. It has been known.

In addition, as applied fields using light, there are imaging technologies that are performed by placing an image sensor at the imaging position of the target object, and application fields that utilize spectral characteristic measurement technology, length measurement technology, display technology, etc. of the target object to be measured. Are known. Furthermore, application fields such as imaging spectrum, which combines the above-mentioned imaging technology and spectral characteristic measurement technology, and three-dimensional measurement, which combines the above-mentioned imaging technology and the above-mentioned length measurement technology, have recently developed. There are also application fields that utilize measurement results of the amount of reflection, transmission, absorption, and scattering of light, or their temporal changes.

In addition to the application fields that utilize the detection and measurement results using light as described above, display technology, optical processing technology, optical control technology, optical communication technology, etc. that utilize light are also known.

Known fields of service provision using light include technical fields that provide services to users by utilizing various information obtained in the application fields using light. Regarding the provision of services to users, not only the provision of information to users and the provision and control of an optimal user environment, but also the provision of services in both directions (reciprocal) with users, there are various methods of providing services. included.

In this field of service provision, there is also a method of providing services to users using activities in a virtual space formed on a network. For example, optical measurement data related to the real world is used to imitate a pseudo-real world in cyberspace. There is also known a form of service provision in which the content of activities such as attractions occurring in cyberspace is optically displayed to the user.

Japanese Patent Application Publication No. 2014-222239 Japanese Patent Application Publication No. 2000-206449 Patent No. 4657379

Various (desirable) optical characteristics are required for each of the above light-related technical fields. Therefore, it is desirable to provide optical characteristics that are suitable for the requirements of each technical field related to light or each optical application field.

For example, high-quality optical properties are required in various fields such as display technology, imaging technology, light control technology, and optical communication technology (information transmission technology using light). In recent years, there has been a trend in the display and imaging fields to desire expressions with a higher sense of reality than ever before. There is a growing tendency to use three-dimensional expressions and clear image expressions as methods of expressing images with a high sense of realism. As one means for producing high-quality optical characteristics or optical characteristics that can be expressed clearly, there is also a method of providing light with little optical interference noise or in which optical interference noise hardly occurs. In order to realize this three-dimensional representation and clear image representation, high-speed processing and transmission processing (transfer processing) for a huge amount of data (amount of information) are required. It is also necessary to provide high signal quality to enable this large-capacity data processing and data transmission.

In order to realize highly accurate detection, measurement, imaging, or light control using light, high reliability and high detection accuracy/measurement accuracy are required for detection, measurement, imaging, and light control. As one means by which high reliability and high precision of this light can be realized, a method for reducing optical interference noise may be provided.

Alternatively, there may be cases where it is desired to reduce the size and weight of an optical device or optical measurement unit. Furthermore, in relation to the above, it may be desired to provide high quality services to users.

In addition, the above is not limited to the provision of a method for generating a predetermined light having desirable or relatively appropriate characteristics in various application fields using light, the provision of an optical characteristic conversion unit, a light source using the same, a method for utilizing a predetermined light, A service providing method and a service providing system may also be provided.

It is also possible to provide an imaging method, a detection method, a detection method, and a display method using the above-mentioned predetermined light, or to provide an optical measurement unit or an optical device using these methods.

In Patent Document 1, in order to improve inspection accuracy on the surface of a target object (semiconductor wafer), the inclination angle of irradiation is changed for each emitted light from a plurality of light sources. Using multiple light sources tends to make the device more complicated and larger. On the other hand, when a single light source is used, the phase difference between the irradiated lights at different tilt angles is always fixed, which causes the problem of increased optical interference noise.

Patent Document 2 describes a method of reducing optical interference noise by passing light passing through a transparent optical element having a different thickness for each region into a common optical fiber. However, in order to realize highly accurate detection, measurement, and imaging, further reduction of optical interference noise is desired.

In Patent Document 3, a solid-state image sensor is provided with a pixel memory, and the exposure time of each pixel can be independently set, thereby allowing ultra-high-speed imaging. However, if optical interference noise mixes into the light irradiated onto the measurement object that is imaged at ultra-high speed or the light reflected from the measurement object, the quality of the captured image will significantly deteriorate.

The above explanation has emphasized the need to provide light with optical characteristics suitable for the requirements of each optical application field, and to provide highly realistic expressions and highly accurate detection/measurement/imaging/light control. explained. However, it is not limited to this, and it is possible to provide convenience to users, high added value, high reliability (high precision), high expressiveness (for example, It may also provide a sense of presence or reality).

In other words, the user's convenience may be improved by providing the user with a hands-free environment, and by providing an additional function and an automatic selection function for the amount of information entered visually by the user. For example, the user's eye movements (movements of the eyeballs), movements of the eyelids and eyebrows such as blinking/winking, facial expressions and audio content, body movements such as gestures, and movements of fingers and hands (arms). It is also possible to provide a highly convenient service/service system or an optical device with high operability by using the information for input or operation.

Additionally, a method (function, device, element) for collecting biometric information of a user in real time, with high precision, and simply may be provided to realize convenience for the user, high added value, and high reliability. For example, a highly reliable service may be provided by using the collected biometric information of the user with an identification function or an authentication function (biometric authentication) to prevent fraud or to prevent inappropriate actions that are not intended by the user. It is not limited to this, but it can also infer the user's mood and health condition from facial expressions, voice, movement characteristics, breathing, pulsation, changes in blood components, etc., and provide the user with an appropriate environment based on the estimation results. It is also possible to provide comfortable services or service systems.

Alternatively, as an example of a method for providing users with high expressiveness (for example, a sense of presence and reality), an environment (service system) that allows clear and detailed three-dimensional expression may be provided.

In the first light and the second light emitted from the same light emitting part and passing through a predetermined optical member,
A perpendicular to the entrance surface of the predetermined optical member is defined, and a perpendicular to the exit surface of the predetermined optical member is defined.
The traveling direction of the first light has an inclination angle between at least one of the normal to the incident surface side and the normal to the exit surface side,
The traveling direction of the second light is tilted with respect to the traveling direction of the first light, or the optical path of the second light within the predetermined optical member is made different from the optical path of the first light. The optical characteristics between the first light and the second light are changed.

FIG. 1 is a configuration diagram showing an example of an overall system outline. FIG. 2 is an explanatory diagram of the relationship between (desirable) optical characteristics required in various technical fields. FIG. 3 is an explanatory diagram of a mechanism in which a collection of lights of different wavelengths constitutes a wave train. FIG. 4 is an explanatory diagram of an experimental system for measuring wave sequence characteristics using an optical interference phenomenon. FIG. 5 illustrates the interference characteristics between single wave trains, one of which is delayed. FIG. 6A shows the experimental results of measuring the wave train characteristics. FIG. 6B is an explanatory diagram of the relationship between successive wave sequences predicted based on the experimental results of FIG. 6A. FIG. 7A is an explanatory diagram of a basic optical system layout diagram using an optical characteristic conversion element. FIG. 7B illustrates a specific structural example of the optical property conversion element. FIG. 7C is an explanatory diagram of a method in which the optical characteristic conversion element utilizes the phase asynchronous characteristic between successive wave trains. FIG. 7D describes another example regarding the specific structure of the optical property conversion element. FIG. 7E illustrates another application example regarding the specific structure of the optical property conversion element. FIG. 8 is an explanatory diagram of the effect of the optical characteristic conversion element in reducing noise in the spectral characteristics. FIG. 9A is an explanatory diagram of a basic optical configuration frequently used in this embodiment. FIG. 9B is an explanatory diagram regarding a specific embodiment of the basic optical configuration. FIG. 9C is an explanatory diagram regarding another specific embodiment of the basic optical configuration. FIG. 9D illustrates a simple method of cutting wavefront continuity at each traveling wave cross-section position. FIG. 9E explains the difference in wavefront continuity between a general imaging lens and a Fresnel lens. FIG. 9F is an explanatory diagram of an embodiment in which wavefront discontinuity is applied. FIG. 9G is an explanatory diagram of another embodiment in which wavefront discontinuity is applied. FIG. 9H explains the relationship between the microscopic reflection direction and the macroscopic reflection direction in the multi-division light reflection element. FIG. 9I is an explanatory diagram of an applied form of FIG. 9G or FIG. 9H. FIG. 10A is an explanatory diagram of the relationship between biological system components and corresponding absorption wavelengths. FIG. 10B is an explanatory diagram of the human eyeball structure. FIG. 11A is an explanatory diagram of an embodiment example regarding the internal structure of a hybrid type light emitting section. FIG. 11B is an explanatory diagram of the structure inside the near-infrared emitting phosphor. FIG. 11C is an explanatory diagram regarding a method for producing a near-infrared emitting phosphor. FIG. 12A is an explanatory diagram of an embodiment regarding an integrated structure of a light source section and a measurement section. FIG. 12B is an explanatory diagram of another embodiment of an integrated structure of a light source section and a measurement section. FIG. 13 shows an explanatory diagram of the principle of the cause of optical noise generation in this embodiment seen from a different perspective. FIG. 14A is an explanatory diagram of an example of an optical noise reduction method. FIG. 14B is an explanatory diagram of another embodiment of the optical noise reduction method. FIG. 14C is an explanatory diagram of an application example regarding the optical noise reduction method. FIG. 14D shows the optical noise reduction effect when using the application described in FIG. 14C. FIG. 15A is a diagram illustrating a comparison of characteristics between a single mode optical fiber and a multimode optical fiber. FIG. 15B is an explanatory diagram of types and characteristics of multimode optical fibers. FIG. 15C is an explanatory diagram of the mode of light passing through the core region of the optical fiber. FIG. 16A is an explanatory diagram of intensity gravity center shift generation using mode addition within an optical fiber. FIG. 16B is an explanatory diagram of an optical noise reduction method using intensity gravity center shift. FIG. 16C is an explanatory diagram of the relationship between the optical characteristic conversion element and optical noise reduction. FIG. 17A is an explanatory diagram of the relationship between the incident angle with respect to the perpendicular to the entrance surface of a predetermined optical member and the optical noise reduction effect. FIG. 17B is an explanatory diagram of the relationship between the number of angular divisions of the optical characteristic conversion element and the optical noise reduction effect. FIG. 18A is an explanatory diagram of an example regarding the optical arrangement within the light source section. FIG. 18B is an explanatory diagram of an embodiment mainly relating to the arrangement of electronic circuits within the light source section. FIG. 19A is a data format explanatory diagram showing a time-varying light emission pattern. FIG. 19B is an explanatory diagram regarding the communication control sequence between the host and the light source unit. FIG. 19C is an explanatory diagram of an example of a control signal format for controlling light emission start timing. FIG. 20A is an explanatory diagram showing information extraction and flow in this embodiment. FIG. 20B is a classification diagram showing information contents extracted in this embodiment. FIG. 20C shows a method for removing disturbance noise for each measurement location/content within the measurement object. FIG. 21A shows a basic data processing method in this embodiment for spectral characteristics and image signals that change over time. FIG. 21B shows another embodiment regarding a data processing method for spectral characteristics and image signals that change over time. FIG. 21C shows an application example regarding a data processing method of spectral characteristics and image signals using exposure by pulsed light emission. FIG. 22 is a diagram illustrating the characteristics of the charge accumulation type signal receiving section. FIG. 23A is an explanatory diagram of an example of signal processing (data processing) leading to the generation of a reference signal after DC component removal. FIG. 23B is an explanatory diagram of an example of the second information extraction method for each wavelength or each pixel. FIG. 24A is an explanatory diagram of an experimental optical system used in a signal processing experiment using a charge accumulation type signal receiving section. FIG. 24B is an explanatory diagram of the spectral characteristics of the irradiation light and the detection light for the measurement target. FIG. 25A shows the detected light amount temporal change characteristics for each different wavelength light. FIG. 25B shows the detected light amount time change characteristics for each different wavelength light. FIG. 26A shows an enlarged view inside the image sensor used in this embodiment. FIG. 26B is a partial explanatory diagram of the internal drive circuit of the image sensor used in this embodiment. FIG. 26C is an explanatory diagram of the operation timing in the drive circuit described in FIG. 26B. FIG. 27A is an explanatory diagram of an embodiment in which a light source section and a measurement section are integrated. FIG. 27B is an explanatory diagram of the internal structure of the optical device when a 3D color image sensor is used in the measurement section. FIG. 28A is an explanatory diagram of a 3D color image (video) collection procedure. FIG. 28B is an explanatory diagram of a reflected light pattern imaging method using light source wavelength light over the entire measurement distance range. FIG. 28C is an explanatory diagram of a reflected light pattern imaging method using light source wavelength light for each measurement distance range. FIG. 28D is a timing explanatory diagram of light source unit light emission and measurement unit exposure during detailed distance measurement. FIG. 28E is an explanatory diagram of a distance measurement method using a combination of multiple pixels. FIG. 28F shows a method of combining light emission and exposure to reduce the effects of speckle noise. FIG. 28G is an explanatory diagram of a signal detection state within the measurement unit that monitors the amount of speckle noise. FIG. 28H is an explanatory diagram of a signal detection state within the measurement unit that reduces the influence of speckle noise. FIG. 29A is a structural explanatory diagram of a linear variable bandpass filter. FIG. 29B is an explanatory diagram of another embodiment in which a light source section and an image sensor are combined. FIG. 30A is an explanatory diagram of the relationship between input devices and output devices for a predetermined service providing domain in cyberspace. FIG. 30B explains an example of the form of an input/output device to a predetermined service providing domain in cyberspace. FIG. 30C illustrates another example input/output device configuration to a predetermined service providing domain in cyberspace. FIG. 31A is an explanatory diagram of a method for adjusting the size of display content in real space and content displayed in cyberspace. FIG. 31B shows an example of an authentication environment when participating in a predetermined service providing domain using biometry. FIG. 31C is an explanatory diagram of a detailed authentication example using biometry. FIG. 32 is an explanatory diagram of an embodiment of providing a service that allows time manipulation in cyberspace. FIG. 33A is an explanatory diagram of four-dimensional coordinate axis directions as seen from the image sensor. FIG. 33B is an explanatory diagram of a four-dimensional mesh structure that captures changes in the surface shape of a measurement target in this embodiment. FIG. 33C is an explanatory diagram of the data structure of the four-dimensional mesh in this embodiment. FIG. 34A is an explanatory diagram of a mapping concept used in a time-manipulable service provision domain in cyberspace. FIG. 34B shows a procedure explanatory diagram for generating a four-dimensional image (video) to be displayed to the user using mapping technology. FIG. 34C shows an example of a method for rendering and coordinate transformation of an individual four-dimensional mesh structure on a map. FIG. 34D is an explanatory diagram of a method of adjusting color intensity according to lighting conditions within the map. FIG. 34E is an explanatory diagram of a coordinate conversion method for three-dimensional display to the user.

The predetermined light generation method, optical characteristic changing unit, light source, predetermined light utilization method, detection method, imaging method, display method, optical measurement unit, optical device, service providing method, and service providing system in this embodiment are described below in the drawings. Explain with reference to.

First, a table of contents related to the explanation of this embodiment will be shown to make it easier to understand the entire explanation.
Chapter 1 Overview of the system used in this embodiment and optical characteristics required for each optical application field Section 1.1 Overview of the system used in this embodiment Section 1.2 Optical characteristics required for each optical application field Overview of characteristics Chapter 2 Basic optical characteristics used in this embodiment Section 2.1 Wave train composed of a set of different wavelength lights Section 2.2 Relationship between different wave trains and light interference characteristics
Section 2.3 Generation of special optical properties using wave chain properties
Section 2.4 Optical noise reduction effect appearing on spectral characteristics
Chapter 3 Embodiment example of changing optical characteristics between two waves emitted from the same light emitting part Section 3.1 Basic optical configuration used in this embodiment Section 3.2 Specific example of basic optical configuration
Section 3.3 Embodiments of other optical configurations
Chapter 4 Hybrid light source section and its usage forms Section 4.1 Relationship between biological components and absorption wavelengths
Section 4.2 Example of internal structure of hybrid light source Section 4.3 Material and structure of near-infrared emitting phosphor and its production method
Section 4.4 Embodiment in which the light source section and measurement section are integrated and miniaturized Chapter 5 Other embodiment examples for reducing optical noise Section 5.1 Features of speckle noise pattern
Section 5.2 Characteristics of various optical fibers and characteristics of light passing through the core region Section 5.3 Method for reducing speckle noise patterns using mode characteristics within optical fibers Section 5.4 Optical noise reduction effect Chapter 6 Time Light source section that can emit arbitrary waveform light in the serial direction
Section 6.1 Arrangement of optical system with high-speed control function for light emission amount Section 6.2 Example of internal structure of light source Section 6.3 Example of format for light emission waveform setting Section 6.4 Example of light emission communication control
Chapter 7 Combination of optical noise reduction and electrical noise reduction Section 7.1 High-precision measurement methods in optical application fields Section 7.2 Various embodiment examples applying lock-in amplification technology Section 7.3 Charge Structure of storage type signal receiver
Section 7.4 Example of signal processing format for charge accumulation type signal Section 7.5 Example of demonstration experiment results
Chapter 8 Embodiment of combination of light source unit and measurement unit with built-in image sensor Section 8.1 Internal structure of image sensor and data acquisition timing in this embodiment Section 8.2 Combination of measurement unit with built-in image sensor and light source unit Combination embodiment Section 8.3 Distance measurement procedure
Section 8.4 Method for reducing the influence of laser speckle noise on measurement
Section 8.5 Hyperspectral detection method using irradiation wavelength control Chapter 9 Service provision Section 9.1 Examples of input/output device formats when providing services Section 9.2 Examples of service provision formats Section 9.3 Obtained by measurement Data format example of 4D data
Section 9.4 Mapping processing
Chapter 1 Overview of the system used in this embodiment and optical characteristics required for each optical application field Section 1.1 Overview of the service providing system used in this embodiment Figure 1 shows the services used in this embodiment A provision system 14 is shown. The light emitted from the light source section 2 is irradiated onto the object 20 via the light propagation path 6. Then, the light obtained from this object 20 enters the measuring section 8 via the light propagation path 6 again. Furthermore, the present invention is not limited to this, and the light emitted from the light source section 2 may be directly incident on the measurement section 8 via the light propagation path 6. In another embodiment, the light emitted from the light source section 2 may reach the display section 18 via the light propagation path 6, and predetermined information may be displayed on the display section 18.

The measuring device 12 in this embodiment includes a light source section 2, a measuring section 8, and an internal system control section 50. Further, an application field (various optical application fields) adaptation section 60 exists outside the measuring device 12. Each of the sections 62 to 76 in the application field (various optical application fields) adaptation section 60 can individually exchange information with the system control section 50.

For example, the information obtained from the measurement results in the measurement section 4 and the sections 62 to 76 in the application field (various optical application fields) adaptation section 60 are used in conjunction to provide services to the user.

The service providing system 14 in this embodiment is composed of the measuring device 12, the application field (various optical application fields) adapting section 60, and the external system 16, and is configured to be able to provide all kinds of services to users. Here, the remaining portion of the service providing system 14 excluding the external system 16 functions independently as the optical device 10.

As a specific application, an example of providing services related to telemedicine will be explained. In this case, the medical/welfare-related test processing unit 70 operates, and the information obtained from the measurement unit 8 can be used to assist in remote diagnosis. Specifically, the blood sugar level obtained by analyzing the data collected from the measurement unit 8 can be used for diagnosis of diabetes. Furthermore, the pulsation waveform obtained at the same time may be used to diagnose arrhythmia related to heart disease.

For example, a processing example will be described when an arrhythmia is detected in a pulsation waveform while measuring a specific user's blood sugar level. The pulsating waveform of a specific user is extracted within the signal processing section 42 and transferred to the characteristic analysis/analysis processing section 62 via the signal/information conversion section (including decoding/demodulation processing) 44 and the system internal control section 50. . Then, this characteristic analysis/analysis processing section 62 analyzes the pulsation waveform and performs pattern matching with the standard waveform and the lesion waveform. As a result, arrhythmia can be detected and defects within the heart can be predicted. The arrhythmia detection result and intracardiac defect prediction information are then transmitted to the medical/welfare-related examination processing section 70 via the in-system control section 50.

Next, the medical/welfare-related test processing unit 70 provides information (for example, sends an e-mail) to the family doctor in the external system 16 via the information transmission path 4. Additionally, if this specific user has concluded a prior contract with a predetermined insurance company (non-life insurance company), the medical/welfare-related inspection processing unit 70 automatically provides information to the insurance company (non-life insurance company). (e.g. send email). As a result, it is possible to provide a service that handles troublesome procedures such as arranging hospitalization and reducing treatment costs on behalf of the user, without placing a burden on the user.

Furthermore, when the patient is undergoing treatment for an illness or a specific disease, the treatment adaptation control/processing unit 68 may be activated, and the doctor may remotely monitor the progress of the treatment. In other words, by tracking temporal changes in blood sugar levels and pulsation waveforms, a distant doctor can understand the progress of the disease and the progress of healing.

The user's health information is not limited to the above, and the user's health information may be used to provide any other service. For example, when signing a contract for non-life insurance such as automobile insurance or unemployment insurance, the non-life insurance company may use the optical device 10 to check the health condition of the user who is the subject of the contract. A service for setting the amount of damages based on the information obtained from the optical device 10 may also be provided.

However, the information obtained from the optical device 10 may be used, for example, to set the interest amount and loan conditions when the user makes a deposit at a bank or when the bank lends the user (a company managed by the user).

As another service provision example, the information obtained from the optical device 10 may be used in educational settings. For example, a student's level of concentration and drowsiness can be predicted based on pulse rate, breathing rate, eye movements, and eyelid movements. The content of the lecture can be changed as appropriate based on the student's concentration level and drowsiness information obtained from the optical device 10. This will improve educational efficiency.

Furthermore, as an example of application of other service provision formats, it is also possible to apply it to abnormality monitoring in public facilities. When people become nervous or excited, their heart rate (pulse rate) tends to increase. Terrorists who are about to commit an incident are secretly in a state of ``nervousness'' or ``excitement,'' and their faces often become stiff from the tension. Therefore, by remotely controlling a surveillance camera and simultaneously measuring the pulse rates of a large number of unspecified people, it is possible to identify people whose pulse rates are abnormally high and whose facial muscles are contracting.

In this embodiment, the optical device 10 may serve as an entrance to cyberspace by using the information transmission path 4. (In other words, the optical device 10 can be directly connected to the cyberspace via the information transmission path 4.) As an example of providing a service corresponding to the role of the entrance to the cyberspace, an individual when entering the cyberspace We provide all kinds of services in cyberspace, including authentication, searching and guiding each user to the optimal location after entering cyberspace, acting on behalf of the user's active actions within cyberspace, and protecting security. Also good.

In the present embodiment, automatic input and identification of blood vessel patterns and fundus patterns at any part of the user's body using the optical device 10 (or the service providing system 14 therein), or a visible light camera built into the measurement unit 8 is performed. Facial recognition and body recognition can be performed using . Therefore, in this embodiment, by using the user-related information collected by the optical device 10, it is possible to provide a personal authentication service when entering cyberspace. Further, the personal authentication service may be provided using any method other than the above (for example, voiceprint detection).

As an example of the physical form of the optical device 10 as an entrance to this cyberspace, a camera section of a personal computer or a mobile terminal (smartphone, tablet, etc.) may be used.

Further, as the physical form of the display unit 18 in the optical device 10, a wearable terminal that can be worn by a user may be used. The wearable terminal that can be worn by the user may take any physical form such as glasses, a hat, a helmet, or a bag.

For example, in glasses-shaped glasses that realize VR (Virtual Reality) and AR (Augmented Reality), and types that the user wears directly, there are places that come into direct contact with the user's skin. At least a portion of the measuring section 8 in the optical device described above may be placed in a region that directly contacts the user's skin.

By measuring the content of specific components such as noradrenaline in the blood through blood analysis, it is possible to estimate the psychological state of the user wearing the terminal, such as a "nervous state" or "excited state". In addition, the user's psychological state can be estimated from the contraction locations of facial muscles on the user's face. Furthermore, as mentioned above, it is also possible to extract measurement subjects who are in a "nervous state" or "excited state" from the pulse rate of the person captured on a remote camera. Furthermore, the present embodiment is not limited to this, and the activity of individual neurons within the user's head can be monitored. Therefore, using the optical device 10, users can efficiently approach cyberspace.

For example, methods for users to take active actions in cyberspace using conventional technology required finger operations such as vocalization and key-in. Therefore, it took a great deal of time to approach cyberspace using conventional technology. In contrast, in the present embodiment, the user's psychological state and intention can be predicted automatically and quickly within the optical device 10, and a prompt and appropriate response to cyberspace can be achieved. Therefore, in this embodiment, it is possible to provide the information 72 desired by the user and deal with cyberspace at high speed without requiring the user to make cumbersome actions such as vocalization or finger movements.

Furthermore, the present invention is not limited to this, and various non-optical sensors 52 within the optical device 10 can be used to provide high user convenience in dealing with cyberspace. For example, a case will be described in which a gyroscope or an acceleration sensor is arranged as the various non-optical sensors 52 to detect the movement of the user's head or a part of the user's body (for example, a hand or a finger). When a user shakes his or her head while displaying an image (video) on the display unit 18 using a glasses-type wearable terminal such as VR or AR, the display screen rotates accordingly. When the user leans forward or leans back, the user moves forward or backward on the display screen. For example, when attempting to move at high speed in cyberspace while playing a game, there is a limit to the response speed of the gyroscope or acceleration sensor. In this case, by predicting the user's psychological state and will and responding quickly and appropriately in cyberspace, the convenience for the user in cyberspace can be greatly improved.

An example of service provision to the user in collaboration between the information providing unit 72, collected information storage 74, and signal processing unit 42 in the service providing system 14 is shown below. For example, consider an example of providing a service in which a menu screen is displayed on a VR screen or an AR screen of a wearable terminal (such as glasses or a helmet) worn by a user. By estimating the user's "likeability" (or degree of discomfort) using the optical device 10 at the same time as detecting the user's line of sight, it is possible to instantly (in a short period of time) display a screen that the user prefers.

For example, 1. A wearable terminal such as VR or AR is incorporated into the display unit 18,
2. The gyroscope and acceleration sensor in the various non-optical sensors 52 detect the movement of the user's head and fingers (or hands),
3. Using the user's biological signals measured by the measurement unit 8, the signal processing unit 42 outputs information regarding the user's biological body,
4. When the system internal control unit 50 integrates and uses the above information,
An identity in cyberspace corresponding to the user using the optical device 10 is formed. Any service can then be provided to the identity within this cyberspace. Furthermore, the present invention is not limited to this, and by operating a robot placed in real space via cyberspace, it is possible to provide further services to users.

For example, tourism services can be provided to users by operating robots that can walk automatically and installed in remote locations. In addition, robots that can walk automatically installed in hospitals and other facilities can be operated to provide nursing care services from a distance. With conventional technology, voice input and user finger (or hand) movements are required for identity manipulation in cyberspace and robot manipulation in real space. When the optical device of this embodiment is used, cumbersome vocalizations and finger movements are not required, and high-speed operation becomes possible. This greatly improves the convenience of providing services in this embodiment.

As another embodiment of providing services using cyberspace, it may also be used for marketing applications. For example, while displaying a predetermined image or video on a VR screen or an AR screen via the information providing unit 72, the user's emotions and intentions may be estimated one by one within the optical device 10. Images, videos, and sounds that are displayed when the user is liked or interested are appropriately stored in the collected information storage section 74. The external system 16 collects the information (images, video, audio) stored in the collected information storage section 74 via the information transmission path 4 at appropriate timing. Next, the information collected within the external system 16 may be analyzed to extract products with purchasing power, and the information may be provided for a fee to a sales company of the corresponding product.

Personal information management is extremely important in providing services in cyberspace in this embodiment. Therefore, among the services provided in this embodiment, the personal information management service itself is a very important service. When a specific user performs activities in cyberspace after entering cyberspace, an account ID (identification) is used to identify each user. When the user's health information and preference information obtained from the optical device 10 are linked to the account ID, it becomes personal information.

As an example of service provision in this embodiment, a personal information management agent may be resident within the collected information storage section 74 or within the characteristic analysis/analysis processing section 62. Information such as “which facial muscles of the user are contracting,” “the content ratio of each component in the blood,” or “which nerve cells are active (nerve impulses)” is collected by the signal processing unit 42. parsed within. Advanced judgments such as "estimation of user emotion", "estimation of user preference", and "estimation of user intention" using this information are performed within the characteristic analysis/analysis processing unit 62. The information obtained by the characteristic analysis/analysis processing unit 62 is stored in the collected information storage unit 74 as appropriate. Then, in response to a request from the external system 16, necessary information is transmitted to the external system 16 via the information transmission path 4.

In the service provision example of this embodiment, the personal information management agent links transmittable external range information to each piece of information obtained by the characteristic analysis/analysis processing unit 62. Therefore, transmittable external range information is set for all information stored in the collected information storage section 74. Then, for each information transmission request from the external system 16, the personal information management agent determines whether transmission to the outside is possible. By performing the personal information management service within the optical device 10 in this manner, highly reliable personal information protection is possible.

As another service provision application example of this embodiment, it may be used as a tool to create artificial intelligence (to make artificial intelligence learn). As the artificial intelligence here, for example, a ``multi-input, multiple-output parallel processing method with a learning function'' used in deep learning technology or quantum computer technology may be used.

Examples of complex analysis/processing for which multiple-input, multiple-output parallel processing is suitable include image analysis and image understanding, language processing and language understanding, and advanced judgments adapted to complex situations. Both the human and artificial intelligence of the measurement object 22 are given their tasks at the same time. Then, the answer given by the human can be regarded as the correct answer, and learning feedback can be applied to the artificial intelligence so that it approaches the correct answer.

These tools may be executed in cyberspace. In this case, the artificial intelligence to be learned is installed in advance on the external system 16, and the correct answer given by the human is notified to the artificial intelligence via the information transmission path 4 from the optical device 10 (or the application field adaptation section 60). can.

Examples of service provision are not limited to those described above, and any service provision may be provided in which the optical device 10 is connected to a cyberspace built on the external system 16 via the information transmission path 4.

Section 1.2 Outline of Optical Properties Required for Each Optical Application Field FIG. 2 shows a list of (desirable) optical properties 102 required for each optical application field 100. In particular, in this embodiment, the required (desired) optical characteristic contents 102 surrounded by a rectangular frame can be met.

The optical application field 100 to which this embodiment is applied has many meanings, as shown in FIG. However, the present embodiment is not limited to this, and all application fields 100 related to light in some way (including display using light) are applicable to this embodiment.

Chapter 2 Basic optical characteristics used in this embodiment Section 2.1 Wave chain of light containing light of different wavelengths
Depending on the wavelengths contained in light, it is generally classified into multi-wavelength light (panchromatic light) and single-wavelength light (monochromatic light). In particular, laser light is considered to be a single wavelength light. However, strictly speaking, all light includes light of different wavelengths. For example, in gas lasers and solid state lasers, the wavelength width of emitted light is relatively narrow. However, even with the same laser, the wavelength width of emitted light from a semiconductor laser (laser diode) is relatively wide, and often has a half width of wavelength of about 2 nm.

FIG. 3 shows the characteristics when wavelength light included within the range of wavelength width Δλ is gathered. Here, FIG. 3(c) shows the progress of light with a center wavelength λ ₀ , and FIGS. 3(a) and 3(e) show the progress of light with wavelengths λ ₀ −Δλ/2 and λ ₀ +Δλ/2. Furthermore, FIGS. 3(b) and 3(d) represent the progress of light with wavelengths λ ₀ −Δλ/4 and λ ₀ +Δλ/4. And FIG. 3(f) shows the result of combining all the wavelength lights. A collection of light formed by the collection of wavelength lights within the range of wavelength width Δλ is called a wave train.

If the peak positions of all the lights match at the center position in FIG. 3, the largest peak will be formed at the center position in FIG. 3(f) where they are combined. Furthermore, as the light beam moves left and right from the center position in FIG. 3, the phases of the light beams of different wavelengths shift. At the left and right ends of FIG. 3, the phases of lights of different wavelengths are completely different. When a phase shift occurs between FIGS. 3(a) to 3(e) in this way, the amplitude of the entire wave train combining them decreases in the peripheral direction.

The above-mentioned wavelength width Δλ means the wavelength width of the wavelength light included in the light emitted from the light source section 2. For example, the spectral intensity characteristics (light intensity characteristics for each wavelength) of the light emitted from the light source section 2 often have non-uniform spectral distribution characteristics within the above wavelength range. In this case, the wavelength half-width (wavelength range with an intensity that is half of the maximum intensity in the wavelength direction) or the e ^-2 width (the wavelength range that has an intensity of e ^-2 with respect to the maximum intensity in the wavelength direction) is defined as the wavelength width Δλ. You can call me.

Furthermore, the present invention is not limited to this, and when the light source section 2 emits multi-wavelength light (panchromatic light), it may be considered that the wavelength resolution within the measurement section 8 corresponds to the wavelength width Δλ. For example, in the measurement unit 8 described later in FIG. 22, one preamplifier 1150 (detection cell) simultaneously detects light of different wavelengths. The wavelength range of wavelength light detected by one preamplifier 1150 (detection cell) corresponds to the wavelength width Δλ. However, the spectral sensitivity characteristics (wavelength dependence of signal detection sensitivity characteristics) detected by this one preamplifier 1150 (detection cell) may be non-uniform. In this case, the wavelength half-width (wavelength range with a detection sensitivity half of the maximum detection sensitivity in the wavelength direction) or the e ^-2 width (the wavelength range with a detection sensitivity of e ^-2 relative to the maximum detection sensitivity in the wavelength direction) is used. ) may be called the wavelength width Δλ.

This wave series characteristic is expressed by the following formula. The individual waves in FIGS. 3(a) to 3(e) can be represented by plane waves with different frequencies ν from ν ₀ −Δν/2 to ν ₀ +Δν/2. Therefore, when integrating a plane wave in this frequency range, the wave chain characteristic is

で与えられる。ここで得られたシンク関数（sinc function）が、図３（ｆ）の包絡線に相当する。また数式１から分かるように、図３（ｆ）の波長は図３（ｃ）の波長と一致する。

is given by The sinc function obtained here corresponds to the envelope shown in FIG. 3(f). Further, as can be seen from Equation 1, the wavelength in FIG. 3(f) matches the wavelength in FIG. 3(c).

The physical distance ΔL ₀ from the center to the end of the wave train shown in FIG. 3(f) is called the coherence length. And this coherence distance is

で与えられる事が知られている。また簡単な計算から波長幅Δλと振動数幅Δνとの関係は下記の式が成り立つ。従って数式２の関係を適用すると、

It is known that it is given by Further, from a simple calculation, the following equation holds true for the relationship between the wavelength width Δλ and the frequency width Δν. Therefore, applying the relationship of formula 2, we get

が導かれる。

is guided.

Next, the experimental results regarding the characteristics around the end of the wave train shown in FIG. 3(f) will be explained. FIG. 4(a) shows the optical system used in the experiment. This optical system is roughly composed of a light source section 2, a sample setting section 36, and a measuring section 8, and light is transmitted between each section via an optical fiber.

A tungsten halogen lamp HL was used as the light source in the light source section 2. A concave mirror CM is placed on the opposite side of the optical path to increase the efficiency of using the light emitted from the halogen lamp HL. That is, this concave mirror CM reflects the light emitted toward the rear of the halogen lamp HL (toward the left side in the figure) and returns it to the inside of the halogen lamp HL. The light that has passed through the interior of the halogen lamp HL then travels toward the front of the halogen lamp HL (to the right in the figure).

A lens L1 with a focal length of 25.4 mm converts the light emitted from the halogen lamp HL into parallel light. Thereafter, a lens L2 with a focal length of 25.4 mm focuses this parallel light onto the entrance surface of the bundle fiber BF. Inside the bundle fiber BF, 320 optical fibers each having a core diameter of 230 μm and an NA of 0.22 are bundled. An optical characteristic changing element 210 is placed in the middle of the parallel optical path between these two lenses L1 and L2.

The filament that emits light within the halogen lamp HL has a size of 2 mm x 4 mm. Therefore, the emitted light from the outermost side of the filament generates off-axis aberration (coma aberration) within the imaging optical system composed of the two lenses L1 and L2. In order to eliminate the influence of this comatic aberration, an aperture A3 with a diameter of 3 mm was placed immediately after the halogen lamp HL.

Inside the sample installation section 36, a lens L3 with a focal length of 50 mm converts the light emitted from the bundle fiber BF into parallel light. The parallel light beam then enters the sample TS. Here, an aperture A10 with a diameter of 10 mm was placed just in front of the sample to improve the accuracy and reproducibility of the obtained spectral characteristic data.

As shown in FIG. 4(a), in this experiment, spectral characteristic data is obtained using the transmitted light of the sample. A lens L4 with a focal length of 250 mm focuses the transmitted light of this sample onto the incident surface of the single-core fiber SF (core diameter 600 μm). As the spectrometer SM, a near-infrared spectrometer (C11482GA manufactured by Hamahoto Co., Ltd.) with a wavelength resolution of 7.5 nm was used. A structural example of the optical characteristic changing element 210 will be described later using FIG. 7B(b).

The structure of the sample TS used in the experiment is shown in FIG. 4(b). That is, a transparent glass plate having a refractive index of "n" and a mechanical thickness of "d = d0 + δd" was placed at the position of the sample TS in the sample setting section 38. A lens L4 having a focal length "F" and a pupil radius "a" focuses the light passing through the transparent glass plate onto the entrance surface of the single-core fiber SF. The inside of the core region on the entrance surface of the single-core fiber SF corresponds to "point P" in FIG. 4(b).

Since the front and back surfaces of the transparent glass plate are uncoated, about 4% of the light passing through the front and back surfaces of the transparent glass plate is reflected by the front and back surfaces. Therefore, the light S ₀ traveling straight through the transparent glass plate and the light S ₁ reflected twice on the front and back surfaces interfere at "point P".

FIG. 5 shows the interference state between the straight light S ₀ and the twice reflected light S ₁ . The position of the envelope characteristic _S0 of the wave train traveling straight through the transparent glass plate was fixed at a reference position. Regarding the function S ₁ representing the envelope characteristic of the wave train after one or two reflections, it was described as a relative position change when the center wavelength λ ₀ was changed from 0.9 μm to 1.7 μm.

The horizontal axis of FIG. 5 represents the coherence length ΔL ₀ expressed by Equation 2 in reference units, and since the mechanical average thickness d ₀ between the front and back surfaces of the transparent glass plate is a fixed value, the wave traveling straight through the transparent glass plate is The mechanical distance between the center position of the wave train S ₀ and the center position of the wave train S ₁ after two reflections is kept constant. Here, consider a case where this mechanical constant distance is converted into a standard unit of coherent distance ΔL ₀ . As shown in Equation 2, the coherence length ΔL ₀ changes in proportion to the square of the center wavelength λ ₀ . Therefore, the relative position between the two wave trains in FIG. 5 appears to change depending on the value of the center wavelength λ ₀ .

The area of the overlapping region (shaded area in FIG. 5) <S0S1> between both wave trains corresponds to the size of the optical interference fringes generated between the two wave trains. As shown in FIG. 5, when the center wavelength λ ₀ is 1.7 μm or 1.5 μm, the wave trains overlap. However, when the center wavelength λ ₀ is 1.1 μm or less, the overlap between the two wave trains becomes “0” and no interference fringes are generated.

Experimental results obtained using the optical system of FIG. 4 are shown in FIG. 6A. As mentioned above, the wavelength resolution of the spectrometer SM was 7.5 nm, and when the thickness _d0 of the transparent glass plate was calculated as 138.40 μm, the measured data and the theoretical calculation results based on existing theory almost matched. However, the region where the measured data and the theoretical calculation results almost match is limited to the wavelength side longer than 1.4 μm. On the wavelength side shorter than 1.4 μm, a discrepancy was observed between the theoretical calculation results based on existing theory and the measured data, as will be explained in the next section.

Section 2.2 Relationship between different wave trains and interference characteristics of light
FIG. 6B(f) shows the result of the wave chain characteristics outside the end β (around the γ region) calculated using the existing theory. According to the existing theory shown in FIG. 6B(f), the amplitude of the wave train decreases and the wave train disappears when moving away from the central part α of the wave train. In other words, in the existing theory, waves propagate discontinuously in space like pulsed light. Continuously emitted light, such as that from a halogen lamp, cannot be explained using existing theories.

In addition, the calculation results using the existing theory shown in Figure 6B(f) are
A] The wave train amplitude is also seen in the region γ outside the end β of the wave train. B] The phase is reversed in the region α to β within the wave train and in the region outside the end (around the γ region). It should appear. However, neither feature [A] nor [B] was observed in the measurement data of FIG. 6A.

FIG. 6B(g) shows a new physical model proposed to solve the problems of the existing theory. As shown in Fig. 6B(g), when a paradigm shift (reversal of the phase angle advancing direction) occurs at the end β of the wave train, it becomes possible to generate the next wave train, and the measurement data in Fig. 6A can be modified. I can explain it well. A physical model in which a reversal of the phase angle advancing direction occurs at the end β of the wave train will be described below.

The characteristics of the envelope of the wave chain near the end (near the β position in Figure 6B) are obtained from Equations 1 and 3.

と、近似される。また複素関数論の見地から正弦関数に関して、

It is approximated as follows. Also, regarding the sine function from the perspective of complex function theory,

の関係が成立する。

The relationship holds true.

Then, by substituting formula 4 and formula 5 into formula 1, we get

と変形できる。ここで

It can be transformed into here

の条件を満足する場所では、下記の関係が成り立つ。

In places where the following conditions are satisfied, the following relationship holds true.

The upper right-hand side of Equation 8 represents the "wave series that precedes (occurs first)" near the end. Further, the lower equation of Equation 8 represents the vicinity of the starting end of the "trailing (later occurring) wave series". A particularly notable point is that "reversal of the phase angle advancing direction" occurs between the upper right side of Equation 8 and the lower equation. In this way, when the "reversal of the phase angle advancing direction" occurs near the end of the "preceding wave series" (near the β position in FIG. 6B), phase synchronization between the component wavelength lights starts immediately thereafter. As a result, a "trailing wave series" occurs.

In electromagnetism, electromagnetic waves propagate in space due to the interaction between an oscillating electric field and an oscillating magnetic field that are generated orthogonally to each other. However, near the end of the "preceding wave series", the oscillating electric field phase and the oscillating magnetic field phase are random among wavelengths of light. It is possible that this random state of the oscillating electric field and oscillating magnetic field forms the basis for the ``reversal of the phase angle direction''.

The above equation 7 shows a conditional theoretical equation for the occurrence of the above paradigm shift. Here, it is important that the relationship between the right side and the left side of the above equation 7 is not an equation, but an approximate expression. In other words, instead of ``reversing the direction of phase angle progression'' at a specific phase value in the ``preceding wave series'', ``reversing the direction of phase angle progression'' occurs at an ``place where the phase is unspecified'' within the ``preceding wave series''. Occur. As a result, phase discontinuity (phase asynchrony) occurs between the "leading wave series" and the "following wave series".

In other words, from the above physical model,
C] The subsequent wave sequence is continuously generated at β near the end of the previous wave sequence (wave sequence continuous generation)
D] The timing at which the subsequent wave series is generated is uncertain, leading to the characteristic that phase discontinuity (phase asynchrony) occurs between the previous and subsequent wave series. The characteristics of the continuous generation of waves in [C] have not been known until now, and can be derived for the first time from this physical model. On the other hand, although the characteristics of [D] are already known, the reason why the characteristics of [D] appear has never been explained until now. This physical model can clearly explain the reason for the feature [D].

Consider the case where the front wave sequence is shifted and overlapped with the rear wave sequence. If there is phase continuity (phase continuity or phase synchronization) between the front and rear wave trains, the phase of the composite light obtained by overlapping the previous wave train and the rear wave train is always uniquely determined. However, due to the nature of [D], the amount of phase shift between the previous and subsequent wave trains always changes. Therefore, when observed over a predetermined period of time (when viewed macroscopically in the time direction), it is impossible to observe interference between previous and subsequent wave sequences. This state is called "incoherence between the previous wave series and the following wave series" when looking at time macroscopically.

Then, in a predetermined period, the intensity of the combined light of the previous wave series and the subsequent wave series becomes equal to the sum of the average intensity of the previous wave series and the average intensity of the subsequent wave series. In this embodiment, this situation is called "strength addition."

Section 2.3 Generation of special optical properties using wave chain properties
FIG. 7A shows the basic arrangement of an optical system using the optical characteristic conversion element 210 in this embodiment. That is, the optical characteristic conversion element 210 divides the initial light 200 into a plurality of lights 202 to 206. Here, a first optical path 222 in the optical property conversion element 210 forms a first light 202 having a first optical property, and a second optical path 224 forms a second light 204 having a second optical property. Form. A photosynthesis site 220 then combines the first light 202 and the second light 204 to form a predetermined light 230. By the way, at least a portion between the first optical path 222 and the second optical path 224 is arranged at different spatial locations. Furthermore, the first optical characteristic that this first light 202 has and the second optical characteristic that this second light 204 has are different from each other. This "difference in optical properties" may also refer to the "phase discontinuity (phase asynchrony)" between the two described in the previous section. Alternatively, in relation to the explanation at the end of the previous section, "incoherence" between at least a portion of the first light 202 and at least a portion of the second light 204 may mean the difference in optical properties. .

Furthermore, the third light 206 having the third optical characteristic may be formed in the third optical path 226 without being limited thereto. In this case, at least a portion of this third optical path 226 may be arranged at a different spatial location than the first optical path 222 and the second optical path 224.

Here, as a method for arranging at least part of the first optical path 222, second optical path 224, and third optical path 226 at different spatial locations, wave front division is performed on the initial light 200. Each of the lights 202 to 206 may be extracted individually. This wavefront division refers to the optical cross-section of the incident initial light 200 (a surface obtained by cutting the light flux constituted by the initial light 200 by a plane perpendicular to the traveling direction of the initial light 200) or the wavefront of the initial light 200. Each region 212 to 216 is placed at a different location on the top, and each light 202 to 206 is individually extracted.

The above technical content will be explained again from the viewpoint of the structure of the optical characteristic conversion element 210 that realizes the optical function. That is, the optical property conversion element 210 used in this embodiment includes a first region 212 and a second region 214 that are different from each other. The optical path length for each region 212 and 214 may also be changed. When the difference between the optical path length of the first light 202 in the first region 212 and the optical path length of the second light 204 in the second region 214 is larger than the above-mentioned coherence length ΔL ₀ , In this case, “phase discontinuity (asynchrony)” (mutually different optical characteristics) occurs between the first light 202 and the second light 204. Furthermore, the spatial structure of the optical characteristic conversion element 210 is such that the first and second lights 202 and 204 can be easily combined to form a predetermined light 230 at the light synthesis location 220.

As a specific example of a spatial structure that facilitates combining the first light 202 and the second light 204 to form the predetermined light 230, there is a structure in which the incident initial light 200 is wavefront-divided into each light 202 and 204. You can have it. That is, a spatial structure may be adopted in which the first region 212 is arranged in a predetermined region within a cross section of the light beam obtained by cutting the light beam by a plane perpendicular to the traveling direction of the incident initial light 200. Then, a spatial structure is adopted in which a second region 214 is arranged in another region within the cross section of the light beam. However, the method is not limited to this, and as another method, the initial light 200 may be subjected to amplitude division or intensity division.

As another application example, a third region 216 is further provided within the optical property conversion element 210, and the third light 206 that has passed through the third region 216 is also combined with other lights 202 and 204 at a light synthesis location 220. Good too.

FIG. 7B(b) shows an example of the structure of this optical property conversion element 210. The optical arrangement in FIG. 7B(a) matches that in FIG. 4(a) already described. In this case, the optical property conversion element 210 is located at the position of the parallel light between the two lenses L1 and L2.

A pair of semicircular glasses with a thickness of 2 mm and 3 mm are attached by rotating them 90 degrees. Next, each pair is rotated 45 degrees and bonded together, thereby completing an optical property changing element divided into eight parts in the angular direction. Here, the glass thicknesses of the eight divided regions differ from each other by 1 mm or more.

In the lower left area A of the optical property changing element 210, the thickness of the optical property changing element (glass) is 0 mm. Therefore, the light passing through this region A passes through a region in the optical characteristic changing element where no glass exists. When proceeding clockwise from area A to area B, area C, etc., the glass thickness changes sequentially to 2 mm, 4 mm, 7 mm, 10 mm, 8 mm, 6 mm, and 3 mm.

When light passes through glass, it has the characteristic of slowing down. Therefore, when light passes through the same mechanical distance, the optical distance (optical path length) changes in a vacuum and in glass. Therefore, the optical path length of the light after passing through the optical characteristic changing element differs depending on which region from the A region to the H region the light passes through. In this embodiment, each light beam passing through each area is called an "element". That is, different elements have different optical distances (optical path lengths) after passing through the optical property changing element 210.

Due to the action of the lens L2 in FIG. 7B(a), all the elements after passing through the optical characteristic changing element 210 are combined within the bundle fiber BF. Here, if the optical path length difference between each element is larger than the coherence length ΔL ₀ (or larger than twice the coherence length ΔL ₀ ), multiple elements are mixed within the bundle fiber BF.

As shown in Equation 2, the value of this coherence length ΔL ₀ is uniquely determined by the center wavelength λ ₀ and the wavelength width Δλ. This center wavelength λ ₀ is determined by the wavelength range of the light used (or the maximum wavelength of the light used) or the wavelength range of the detection light used in the measuring section 8 (or the maximum wavelength of the detection light). The wavelength width Δλ is determined by the wavelength width of the light used or the detection performance (for example, wavelength resolution) of the measuring section 8.

BK7 was used as the material of this optical property changing element 210 (glass), and an antireflection coating was formed on the interface (front and back surfaces) where light enters and exits. The refractive index of BK7 is represented by n, and the glass thickness in each region in FIG. 7B(b) is represented by d. Then, the optical path length within each region can be calculated as "d(n-1)", and the glass thickness between each region in FIG. 7B(b) differs by 1 mm or more.

Under the measurement conditions for spectral characteristics, which will be explained in the next section using Figure 8, the difference in glass thickness between the above regions is larger than the coherence length ΔL ₀ (or twice the coherence length ΔL ₀ ). .

FIG. 7C shows the operating principle when the characteristics of the continuously generated multiple wave trains described in the previous section are applied to the optical arrangement described in FIG. 7A. As already explained in the previous section, it is considered that there is an unsynchronized phase relation 402 between the initial wave trains 400 that occur one after the other.

The initial light 200 that has entered in the form in which the initial wave train 400 shown in FIG. 7C(a) is continuously generated is wavefront-split when it passes through the optical characteristic conversion element 210 that operates/controls the phase synchronization characteristic. FIG. 7C(b) shows the spatial propagation state (wave train state 406) of the first light 202 that has passed through the first region 212 in the optical characteristic conversion element 210 of FIG. 7A. The amplitude in FIG. 7C(b) is smaller than the amplitude in FIG. 7C(a) because the first light 202 was extracted as a result of wave front divided of the initial light 200.

FIG. 7C(c) shows the spatial propagation state (wave train state 408) of the second light 204 extracted after passing through the second region 214. Although the amplitude in FIG. 7C(c) is almost the same as that in FIG. 7C(b), there is a difference in optical path length between the two. Therefore, in FIGS. 7C(b) and 7C(c), the center positions of the wave trains 406 and 408 are shifted.

As shown in FIG. 7C(a), phase asynchrony (phase discontinuity) 402 occurs between different wave trains 400, and the size of one wave train is given by 2ΔL ₀ (see FIG. 3(f)). . Therefore, if the optical path length difference between the first region 212 and the second region 214 in the optical characteristic conversion element 210 in FIG. 7A is set to 2ΔL ₀ or more, the phase asynchronization at the same position between FIG. 7C (b) and (c) will occur. 402 happens.

FIG. 7C(d) shows a situation where both wave trains 406, 408 are synthesized or combined 410 to form a predetermined light 230 at a light synthesis location 220. When the optical path length difference between the two is larger than the double value _2ΔL0 of the coherence length shown in Equation 2, the wave trains 406 and 408 that are phase asynchronous 402 are combined and the light intensity is averaged ( ensemble average effect of intensities) 420 occurs. Accordingly, the optical noise averaging effect (smoothing effect or reduction effect) between the optical noise generated within the first light 202 and the optical noise generated within the second light 204 is increased. get up.

Not limited to the above conditions, for example, even if the optical path length difference between the first region 212 and the second region 214 is larger than the coherence length, elements that are asynchronous (discontinuous in phase) 402 with each other are mixed in the predetermined light 230. Fit. Therefore, even when the optical path length difference is greater than the coherence length, light intensity averaging 420 occurs in a portion, resulting in the effect of optical noise averaging (smoothing or reduction).

FIG. 7D shows an application example of the embodiment of the structure of the optical property conversion element 210. A 1 mm thick semicircular glass is rotated 30 degrees and adhered, and a 6 mm thick semicircular glass is further adhered. Then, when viewed from the light traveling direction 348, the light is divided into 12 parts at equal intervals in the angular direction. In this embodiment, a division method of dividing the wavefront cross section of light into angular directions with respect to the optical axis in the light traveling direction 348 is referred to as "angle division." Specifically, this means the area division (wavefront division) indicated by the broken line in FIG. 7D(c). The embodiment shown in FIG. 7D is divided into 12 parts at equal intervals in the angular direction (12 angular divisions). As a result, a difference in glass thickness of 1 mm or more occurs between each of the angularly divided regions.

FIG. 7D further has a structure in which cylindrical glasses of different diameters are stacked and bonded. In this embodiment, the division method of dividing the wavefront cross section of light in the radial direction with reference to the optical axis in the light traveling direction 348 is referred to as "radial division." Specifically, this refers to region division (wavefront division) indicated by the solid line in FIG. 7D(c), and region division is performed for each circumference with a different radius. In the embodiment of FIG. 7D, it is divided into four parts in the radial direction (radius divided into four parts). In the structure of the optical characteristic conversion element 210 shown in FIG. 7D, it is divided into 12 parts in the angular direction and 4 parts in the radial direction. Therefore, the number of divided areas is 48 (12×4). However, the number of divisions is not limited to this, and the number of divisions may be set arbitrarily.

In the embodiment shown in FIG. 7D, the diameter of the radius division boundary line is set so that the area of each radius division area is equal. However, the diameter of each cylindrical glass may be set at arbitrary intervals without being limited thereto. Further, the division method may be changed depending on the intensity characteristics of the light passing through (or reflecting) inside the optical characteristic conversion element 210. For example, consider a case where the optical characteristic conversion element 210 is used for light having a non-uniform intensity distribution. This light may have an intensity distribution in which the central intensity is high and the peripheral intensity is low. In this case, the diameter of the boundary line of the radius division may be set so that the intensity of each element passing through each division area is approximately equal.

FIG. 7E shows another embodiment of the structure of the optical property conversion element 210. Here, the division method is changed according to the intensity distribution characteristics of the light using the optical characteristic conversion element 210.

In FIG. 7B(b) or FIG. 7D(c), the angle is divided at equal intervals. For example, if the intensity distribution characteristics of light are non-uniform based on the angle method using the optical axis as a reference, variations in the amount of light will occur for each element passing through the divided regions. An example in which the intensity distribution characteristics of this light are non-uniform in terms of angle is shown in FIG. 7E(a). The cross section 510 of the laser light emitted from the light emitting location 502 of the semiconductor laser device 500 generally has an elliptical shape in many cases.

The division angle interval between the boundary lines in the optical characteristic conversion element 210 shown in FIG. 7E(b) is narrowed in the long axis direction of the laser beam cross section 510. On the other hand, in the short axis direction of the laser beam cross section 510, the division angle interval between the boundary lines is wide. When the division angle intervals of the angle division are made non-uniform in this way, the amount of variation between the intensities of elements passing through each division region is reduced. In this way, when the intensity of each element passing through each divided region becomes almost equal, the amount of optical noise in the predetermined light 230 (FIG. 7A) after synthesis is reduced (averaging or smoothing the optical noise generated in each element). ) will be more effective.

Section 2.4 Optical noise reduction effect appearing on spectral characteristics
FIG. 8A shows experimental results regarding the optical noise reduction effect when using the optical characteristic conversion element 210. The optical system shown in FIG. 7B(a) was used in the experiment, and a diffuser plate with an average surface roughness Ra of 2.08 μm was arranged as the sample TS. Optical noise is generated from the minute irregularities on the surface of the diffuser plate. The spectral intensity characteristics (measurement wavelength dependence) of the relative intensity ([straight-passing light intensity when disposing the diffuser plate] ÷ [straight-passing light intensity before disposing the diffuser plate]) obtained from the spectrometer SM has the above-mentioned optical Contains noise.

The vertical axis in Figure 8 indicates the value after normalizing the amount of variation in spectral intensity (the amount of intensity difference from the average value of spectral intensity in the wavelength direction) resulting from optical noise generated in the diffuser plate by the average value ([amount of variation ] ÷ [average value]) represents the standard deviation value. Further, the horizontal axis in FIG. 8 represents the number of optical path divisions (the number of area divisions) within the optical characteristic conversion element 210. Here, the condition of "number of optical path divisions=1" represents the conventional technique before the optical characteristic conversion element 210 is inserted.

As the number of optical path divisions (the number of area divisions) increases, the amount of optical noise (standard deviation value) clearly decreases. Each element in the optical characteristic changing element 210 passes through a diffuser plate and generates optical noise. However, the optical path to reach the spectroscope SM varies slightly from element to element. Therefore, the optical noise characteristics appearing within each element differ slightly from each other. When the intensities of all elements having different optical noise characteristics are added, the light intensity is averaged 420 (FIG. 7C(d)) between the different optical noise characteristics. As a result, the optical noise characteristics are smoothed (the amount of optical noise is reduced based on averaging).

Effect of reducing the amount of optical noise when a diffuser plate with an average surface roughness Ra of 1.51 μm is inserted into the light source section 2 (between the optical property conversion element 210 and the condenser lens L2) in FIG. 7B(a) is shown in FIG. 8(b). It was confirmed that optical noise was further reduced due to the synergistic effect of the optical characteristic conversion element 210 and the diffuser plate corresponding to the wavefront phase characteristic conversion member.

Chapter 3 Embodiment Example of Changing Optical Characteristics between Two Waves Emitted from the Same Light Emitting Section Section 3.1 Basic optical configuration used in this embodiment Figure 9A is used in this embodiment The basic optical configuration is shown. Two waves of first light 202 and second light 204 or 208 are emitted from the same light emitting unit 470. Then, the predetermined optical member 90 changes the optical characteristics between these two waves. Here, the two waves of the first light 202 and the second light 204 or 208 emitted from the same light emitting section 470 may pass through the predetermined optical member 90, or may pass through the entrance surface 92 of the predetermined optical member 90. It may be reflected by In any case, after passing through this predetermined optical member 90, the optical characteristics between the first light 202 and the second light 204 or 208 change.

In particular, in this embodiment, an incident surface side perpendicular line 96 that is perpendicular to the incident surface 92 of the predetermined optical member is defined. Then, the first light 202 is incident at an angle θ (θ≠0) inclined with respect to the normal line 96 on the incident surface side. Further, the second light 204 is incident at a different angle from the first light 202. Therefore, the traveling direction of the light before entering the predetermined optical member 90 is that the first light 202 and the second light 204 travel in different directions.

The second light 208 different from the first light 202 is defined as a light 208 that travels through a different optical path than the first light 202, rather than the light 204 that travels in a direction different from the first light 202. Also good. In this case, the traveling direction of the second light 208 is parallel to the first light 202 (that is, the direction of travel of the second light 208 is the same as that of the first light 202 with respect to the normal 96 to the entrance surface of the predetermined optical member. (the second light 208 may be incident on the second light 208). However, the second light 208 may travel in a different direction from the first light 202 and may pass through a different optical path from the first light 202.

When the first light 202 passes through the predetermined optical member 90, after passing through the predetermined optical member 90, the first light 202 passes through the exit surface 94 of the predetermined optical member. Also, at this time, a perpendicular line 98 on the exit surface side that is perpendicular to the exit surface 94 of the predetermined optical member is defined. The traveling direction of the first light 202 after passing through the exit surface 94 of the predetermined optical member may have a predetermined inclination angle with respect to the exit surface side perpendicular 98, or may have a predetermined inclination angle with respect to the exit surface side perpendicular 98. They may have a parallel relationship.

However, when the first light 202 passes through the predetermined optical member 90, as shown in FIG. 9A, the traveling direction of the second light 204 after passing through the exit surface 94 of the predetermined optical member is It is necessary to have an inclination (a non-parallel relationship) with respect to the traveling direction of the first light 202.
Further, when the first light 202 passes through the predetermined optical member 90, the optical path of the second light 208 after passing through the output surface 94 of the predetermined optical member is the optical path of the first light 202 after passing. It needs to be different. However, the traveling direction of the second light 208 after passing through the output surface 94 of the predetermined optical member may be parallel to the traveling direction of the first light 202 after passing.

The important thing here is
1. The first light 202 is incident on the entrance surface 92 of the predetermined optical member at an angle inclined with respect to the normal line 96 on the entrance surface side of the predetermined optical member 90 .
2. Before entering the entrance surface 92 of the predetermined optical member, the second light 204 travels in a direction non-parallel to the first light 202, or the second light 208 travels on a different optical path from the first light 202. progresses.

In any case, the first light 202 and the second light 204 or 208 after passing through the predetermined optical member 90 are combined (or mixed) at the light synthesis location 220 to form the predetermined light 230.

The basic concept explained in FIG. 9A is summarized below. In the first light 202 and the second light 204 or 208 emitted from the same light emitting unit 470 and passing through the predetermined optical member 90,
An entrance surface side perpendicular 96 perpendicular to the entrance surface 92 of this predetermined optical member 90 and an exit surface side perpendicular 98 perpendicular to the exit surface 94 of this predetermined optical member 90 are defined,
The traveling direction of the first light 202 has an inclination angle between at least one of the normal to the incident surface side 96 and the normal to the exit surface side 98,
The traveling direction of the second light 204 is tilted with respect to the traveling direction of the first light 202, or the optical path of the second light 208 within the predetermined optical member 90 is set to be the same as the optical path of the first light 202. The optical characteristics between the first light 202 and the second light 204 or 208 are changed by making the light different.

The relationship between the predetermined optical member 90 described here and the optical characteristic conversion element 210 described in the previous chapter will be described below. In this embodiment, an example of an embodiment of the predetermined optical member 90 includes the optical characteristic conversion element 210 in FIG. 7A. In other words, from the explanation up to the previous chapter, the main function of the optical characteristic conversion element 210 is to create an optical path length difference between the first light 202 and the second light 204 (including the third light 206). The main focus was on If this optical path length difference is set to greater than or equal to the coherence length ΔL ₀ (twice), it is possible to interrupt the phase continuity between the wave trains in both (de-synchronize the phases 402). In comparison, the function of the predetermined optical member 92 described using this embodiment has a function that includes the optical characteristic conversion element 210.

This predetermined optical member 92 also provides different optical characteristics between the first light 202 and the second light 204 (including the third light 206). Here, phase desynchronization (phase discontinuity) 402 is cited as an example of the "mutually different optical characteristics". Further, as another example of the "mutually different optical characteristics", a mode change (within the waveguide element 110), which will be described later with reference to FIG. 9B, may be generated.

As an explanation using this embodiment, a description will be given of generation of phase desynchronization (phase discontinuity) 402 and mode change as different optical characteristics provided between the first light 202 and the second light 204. However, the present invention is not limited thereto, and the predetermined optical member 92 may provide any difference in optical characteristics between the first light 202 and the second light 204.

The positioning of the predetermined optical member 90 within the service providing system 14 and optical device 10, which have already been explained using FIG. 1, will be explained. In this embodiment, the service providing method 80 corresponds to an overall concept.

A service providing system 14 is defined as a means for realizing this service providing method 80. The service providing system 14 also includes an optical device 10. Here, the predetermined light utilization method 82 is positioned as part of the operation of this optical device 10.

The optical measurement unit 84 constitutes the optical device 10 as a part of the optical device 10. However, the optical measurement unit 84 is not only used in a predetermined light utilization method 82 . The light source section 2 is included within this optical measurement section 84.

The interior of this light source section 2 is comprised of a light emitting section 470, a predetermined optical member 90, and a light synthesis location 220. Here, at the predetermined optical member 90 and the light synthesis location, the first light 202 and the second light 204 or 208 emitted from the light emitting section 470 are manipulated to form the predetermined light 230.

Section 3.2 Specific Example of Basic Optical Configuration FIG. 9B shows a specific example of an embodiment in which the predetermined optical member 90 described in FIG. 9A and the light synthesis location 220 are combined. Here, the core region 112 within the waveguide element 110 functions as both the light synthesis location 220 and the predetermined optical member 90. A specific form of this waveguide element 110 may be an optical fiber, an optical waveguide, or a light guide.

In FIG. 9B, the entrance surface of the waveguide element 110 corresponds to the entrance surface 92 of the predetermined optical member in FIG. 9A. Similarly, the exit surface of the waveguide element 110 corresponds to the exit surface 94 of the predetermined optical member in FIG. 9A.

There are two types of shapes for the entrance surface of the optical fiber 110: a structure cut perpendicular to the optical axis and a structure cut at a predetermined angle. Here, we will temporarily consider the shape of the entrance surface (and the shape of the exit surface) cut perpendicularly to the optical axis within the optical fiber 110. Then, the entrance surface side perpendicular line 96 that is perpendicular to the entrance surface 92 of the predetermined optical member becomes parallel to the optical axis direction within the optical fiber 110. In this case, similarly, the exit surface side perpendicular 98 that is perpendicular to the exit surface 94 of the predetermined optical member is also parallel to the optical axis direction within the optical fiber 110 .

The first light 202 enters the core region 112 in the waveguide element (optical fiber/optical waveguide/light guide) 110 by setting the incident angle θ of the first light 202 with respect to the normal line 96 on the incident surface side to a predetermined value or more. Consider the case where In this case, as shown in FIG. 9B, the first light 202 is reflected at the interface between the core region 112 and the cladding region 114. Since the length of the actual waveguide element (optical fiber/optical waveguide/light guide) 110 is sufficiently long, reflection at this interface is repeated many times. As a result, the first light 202 forms a higher-order mode other than the fundamental mode (for example, a TE2 mode described later in FIG. 16C(b)) within the core region.

On the other hand, consider a case where the second light 204 is made to enter from a direction substantially parallel to the perpendicular line 96 on the side of the incident surface, and the second light 204 is made to enter the central portion of the core region 112. In this case, the second light 204 travels straight through approximately the center of the core region 112 . The second light 204 is reflected much fewer times at the interface between the core region 112 and the cladding region 114 than the first light 202. As a result, the second light 204 forms a fundamental mode (for example, the TE1 mode described later in FIG. 16C(a)) within the core region.

In this way 1. 2. The first light 202 is incident on the entrance surface 92 of the predetermined optical member at an angle inclined with respect to the normal line 96 on the entrance surface side of the predetermined optical member 90; If the optical arrangement is devised so that the second light 204 travels in a direction non-parallel to the first light 202 before entering the entrance surface 92 of a predetermined optical member, the first light 202 and the second light 204 are A "difference in modes within the core region 112" occurs, which corresponds to different optical properties (optical properties that have changed from each other) between the light 204 and the light 204. A method for reducing speckle noise (optical noise) using the difference in mode between the two waves (first light 202 and second light 204) will be described later in Section 5.3.

Furthermore, as shown in FIG. 9B, the angle ζ formed by the first light 202 emitted from the waveguide element (optical fiber/optical waveguide/light guide) and the normal line 98 on the exit surface side also has a large angle. When confirmed in actual experiments, the emission pattern (far field pattern) of the first light 202 from the waveguide element (optical fiber/optical waveguide/light guide) is a "doughnut-shaped pattern" (with different regions centered on the optical axis). This pattern shows a pattern in which the light intensity decreases and the light intensity increases in areas away from the center of the optical axis.

Similarly, the light intensity distribution of the second light 204 emitted from the waveguide element (optical fiber/optical waveguide/light guide) increases as it approaches the exit surface side perpendicular 98 (the light intensity increases as it approaches the exit surface side perpendicular 98). (The light intensity emitted in the parallel direction is maximum).

A specific embodiment in which the traveling direction of the second light 204 is tilted with respect to the traveling direction of the first light 202 to change the optical characteristics between the two before the second light 204 enters the entrance surface 92 of the predetermined optical member 90 in FIG. 9A. An example is shown in Figure 9B. As another embodiment of FIG. 9A, FIG. 9C shows a specific embodiment in which the second light passes through a different optical path from that of the first light 202 to change the optical characteristics of both.

An example of an embodiment of the predetermined optical member 90 shown in FIG. 9C is a transparent parallel flat plate having a light reflecting surface 118 in part. An antireflection film is formed on the surface of this transparent parallel flat plate other than the light reflecting surface 118 (the incident surface 92 of the predetermined optical member). In the predetermined optical member 90 shown in FIG. 9C, the front surface (front surface) corresponds to the entrance surface 92 of the predetermined optical member, and the back surface (back surface) corresponds to the output surface 94 of the predetermined optical member.

The collimating lens 318 converts the diverging light emitted from the light emitting section 470 into parallel light. When a semiconductor laser element 500 is used as the light emitting section 470, as shown in FIG. 7E, a laser beam cross section 510 in a parallel light state takes an elliptical shape. In the embodiment of FIG. 9C, the minor axis direction 88 within this elliptical shape is parallel to the plane of the paper. Therefore, the long axis direction within this elliptical shape is perpendicular to the plane of the paper.

At this time, the direction of electric field vibration within the laser beam in the parallel light state coincides with the short axis direction 88. A predetermined optical member 90 made of a transparent parallel flat plate is arranged at an angle with respect to the traveling direction of the laser beam in the parallel light state. Here, the predetermined optical member 90 is tilted along a plane that includes the direction of electric field vibration within the laser beam (a plane that includes the plane of the paper). Therefore, the direction in which the entrance surface 92 and the exit surface 94 of the predetermined optical member are inclined has a P-wave (parallel wave) relationship with respect to the electric field vibration direction within the laser beam. It is generally known that the light transmittance of P waves is high at the entrance surface 92 and the exit surface 94. Therefore, by tilting the inclination direction of the entrance surface 92 or the exit surface 94 of a predetermined optical member in the direction of the P wave with respect to the electric field vibration direction in the laser beam, the transmission efficiency of the light passing through the entrance surface 92 or the exit surface 94 can be increased. There is an effect that can be done.

The traveling direction of the parallel light after passing through the collimating lens 318 is inclined by an angle θ (θ≠0) with respect to the perpendicular 96 on the incident surface side of the predetermined optical member. When the incident surface 92 and the exit surface 94 of a predetermined optical member are in a parallel relationship, the angle ζ between the traveling direction of the light exiting the exit surface and the perpendicular line 98 to the exit surface side coincides with θ (ζ= θ≠0).
In this embodiment, the output surface 94 of the predetermined optical member 90 has a specific light reflectance. Then, a part of the light that passes through the entrance surface 92 of the predetermined optical member passes through the exit surface 94 of this predetermined optical member, and the remaining light is reflected by the exit surface 94. In the embodiment shown in FIG. 9C, the light that has passed through the exit surface 94 of this predetermined optical member is treated as the first light 202.

The light reflected by the output surface 94 is reflected again by the light reflection surface 118, and a part of this reflected light passes through the output surface 94 of the predetermined optical member. Here, the light passing through this exit surface 94 is treated as second light 208. As is clear from FIG. 9C, this second light 208 passes through a different optical path from that of the first light 202 described above. Further, the optical path length of the second light 208 within the predetermined optical member 90 is different from the optical path length of the first light 202. If the optical path length difference between the two is set to be larger than the coherence length ΔL ₀ (twice the value) shown in Equation 2, the phase continuity between the first light 202 and the second light 208 will be interrupted. (The relationship is phase asynchronous 402). In other words, the optical characteristics between the first light 202 and the second light 208 change from the viewpoint of phase continuity (phase synchrony).

Immediately after passing through the output surface 94 of the predetermined optical member 90, the laser beam cross section 510 of each of the first light 202 and the second light 208 has an elliptical shape. However, the first light 202, second light 208, and third light 206 immediately after passing through the output surface 94 are aligned in the short axis direction 88. As a result, an effect is produced in which the elliptical shape of the laser beam cross section 510 is corrected. That is, when the predetermined optical member 90 is tilted within a plane including the minor axis direction 88 of the laser beam cross section 510 emitted from the semiconductor laser element 500 (light emitting section 470), the elliptical shape of the laser beam cross section 510 is corrected. .

At the end of Section 3.2, the features of the optical arrangement of this embodiment will be summarized. As shown in FIG. 9A, the first light 202 is incident from a direction of an inclination angle θ (θ≠0) with respect to a perpendicular line (perpendicular line 96 to the incident surface side) perpendicular to the incident surface 92 of the predetermined optical member 90. Then, the predetermined optical member 90 changes the optical characteristics between the first light 202 and the second light 204 or 208 after passing through the predetermined optical member 90 .

In the example embodiment of FIG. 9B, the direction of incidence of the second light 204 is different from the direction of incidence of the first light 202. The difference in optical characteristics between the first light 202 and the second light 204 corresponds to a "difference in light propagation mode within the core region 112."

In the example embodiment of FIG. 9C, the optical path of the second light 208 is different from the optical path of the first light 202. The difference in optical characteristics between the first light 202 and the second light 208 corresponds to "phase asynchronization 402 (discontinuation of phase continuity) between the two".

Note that the optical characteristics that change between the first light 202 and the second light 204 or 208 after passing through the predetermined optical member 90 are not limited to those described above, and may include any difference in optical characteristics or any change in optical characteristics (discontinuous). gender) is also fine.

Section 3.3 Other Examples of Embodiments of Optical Configuration Other specific individual embodiments of the predetermined optical member 90 shown in FIG. 9A will be described in Section 3.3. In the various specific individual embodiments described in this Section 3.3:
A) The incident surface side perpendicular 96 or the exit surface side perpendicular 98 of the predetermined optical member 90 is tilted with respect to the incident direction of the first light 202,
B) The entrance surface 92 or the exit surface 94 of the predetermined optical member 90 has a discontinuous surface (microscopic step shape).

FIG. 9D(a) shows an example of a conventional optical system that corrects the elliptical shape of the laser beam cross section 510 from the semiconductor laser element 500. In order to clarify the effect of the above (B), the difference between FIG. 9D(a) and the above (B) will be explained below.

The collimating lens or cylindrical lens 120 in FIG. 9D(a) converts the diverging light (divergent laser light) emitted from the light emitting section 470 (semiconductor laser element 500) into parallel light. In this parallel light state, the equiphase front 128 of the light is flat. Further, the laser beam cross section 510 in this parallel light state often has an elliptical shape (see FIG. 7E(a)). Here, the short axis direction 88 of the elliptical shape coincides with the paper surface direction. The wedge prism 130 stretches the parallel light in the minor axis direction, corrects the elliptical shape, and converts it into a substantially circular shape.

The traveling direction of the parallel light immediately after passing through the collimating lens or cylindrical lens 120 has an inclination with respect to the perpendicular line 96 on the incident surface side of the wedge prism 130. Therefore, the optical arrangement of FIG. 9D(a) satisfies the feature of (A) above. However, what is important is that the equiphase plane 128 in the parallel light after passing through the wedge prism 130 forms a uniform flat surface everywhere. In the optical noise reduction method explained in Section 2.3, the equiphase surface 128 in parallel light is divided into multiple regions, and the optical path length difference for each region is set to a coherence length ΔL ₀ (or twice that) or more. change to However, in a state where the equiphase plane 128 in the parallel light after passing through the wedge prism 130 forms a uniform flat surface as shown in FIG. 9D(a), the optical noise reduction effect described in Section 2.3 does not appear. do not have.

In FIG. 9D(b), compared to FIG. 9D(a), the exit surface 94 of the predetermined optical member 92 has a minute step difference, making it a discontinuous surface. Therefore, the equiphase front 128 of the light after passing through the output surface 94 of the predetermined optical member 92 is collapsed, and the optical noise reduction effect described in Section 2.3 can be achieved.

In FIG. 9D(b), the output surface 94 of the predetermined optical member 92 is a discontinuous surface. However, the present invention is not limited thereto, and the entrance surface 92 of the predetermined optical member 92 may be a discontinuous surface. Making at least a portion of the entrance surface 92 and the exit surface 94 of the predetermined optical member 92 into discontinuous surfaces with fine steps means the content of (B) above. Thereby, the optical noise reduction effect described in Section 2.3 can be achieved.

Next, the relationship between various specific individual embodiments described in Section 3.3 of this book including FIG. 9D(b) and the content of explanation in Section 3.1 using FIG. 9A will be described. Among the lights emitted from the same light emitting unit 470 and passing through the collimating lens or cylindrical lens 120, the light passing through the center of the collimating lens or cylindrical lens 120 is made to correspond to the first light 202. Further, the light that has passed through the peripheral portion of the collimating lens or the cylindrical lens 120 is made to correspond to the second light 204. The first light 202 and the second light 204 have different optical paths because they pass through different locations within the collimating lens or cylindrical lens 120.

The traveling direction of the first light 202 is inclined by an angle θ (θ≠0) with respect to a perpendicular to the entrance surface 96 that is orthogonal to the entrance surface 92 of the predetermined optical member 90. By providing the optical arrangement described in (A) above, the optical noise reduction effect described in Section 2.3 can be achieved.

Immediately after passing through the collimating lens or cylindrical lens 120, the parallel light forms a flat equiphase surface 128. Among them, the equiphase front 128 of the second light 204 reaches the entrance surface 92 of the predetermined optical member first. Then, the equiphase front 128 of the first light 202 reaches the entrance surface 92 of the predetermined optical member with a delay. In this way, by tilting the traveling direction of the first light 202 by the angle θ (θ≠0) with respect to the perpendicular line 96 on the incident surface side of the predetermined optical member 90, the distance between different optical paths until reaching the predetermined optical member 90 is increased. The optical path length changes.

In order to exhibit the optical noise reduction effect described in Section 2.3, it is necessary to set this optical path length difference to be larger than the coherence length ΔL ₀ (twice the value). In order to satisfy this condition, when the beam size of the light incident on this predetermined optical member 90 is D,

または

or

となるように傾き角θを設定するのが望ましい。上記の条件式内のＬmaxは、光源部２または光学的計測部８４や光学装置１０の実装寸法の条件から決まってくる。従ってＬmaxの値は１０ｍ、望ましくは１ｍに設定しても良い。

It is desirable to set the inclination angle θ so that Lmax in the above conditional expression is determined from the mounting dimensions of the light source section 2, the optical measurement section 84, and the optical device 10. Therefore, the value of Lmax may be set to 10 m, preferably 1 m.

The beam size D of the light incident on this predetermined optical member 90 may be set by the effective luminous flux diameter. That is, the maximum diameter of light that can pass through the collimating lens or the cylindrical lens 120 is considered to be the effective luminous flux diameter. However, the invention is not limited thereto, and the width (half-width or half-value diameter) of a region where the intensity is half the maximum intensity at the center in the intensity distribution of light incident on the predetermined optical member 90 may be regarded as the beam size D of light. In addition, in addition to that, the width (e ^-2 width or e ^-2 diameter) of the region where the intensity is e ^-2 of the maximum intensity at the center in the intensity distribution of light incident on the predetermined optical member 90 is the beam size D of light. It may be considered as

When the collimating lens or cylindrical lens 120 converts the emitted light from the light emitting unit 470 into parallel light, the difference between the focal length F of the collimating lens or cylindrical lens 120 and the NA (numerical aperture) value is D=2FNA. There is a relationship between However, here, the effective beam diameter of the collimating lens or cylindrical lens 120 is regarded as the beam size D of light. Therefore, using this relationship, the above formula 9 and the above formula 10 are

または

or

の条件を設定できる。

conditions can be set.

When the semiconductor laser element 500 is used as the light emitting section 470, the cross section 510 of the laser light emitted therefrom has an elliptical shape (see FIG. 7E(a)). The minor axis direction 88 of this ellipse may coincide with the electric field vibration direction of the laser beam. Therefore, when the predetermined optical member 90 is tilted within a plane including this minor axis direction 88 (in the plane of the paper in FIG. 9D(b)), the direction of inclination of the incident surface 92 of the predetermined optical member 90 becomes the P-wave incident direction of the laser beam. . It has an optical characteristic that the light transmittance at the interface (incidence surface 92) becomes high when P waves are incident. Therefore, tilting the predetermined optical member 90 within a plane including the minor axis direction 88 has the effect of increasing the utilization efficiency of the light transmitted through the predetermined optical member 90. Furthermore, at the same time, there is an effect that the ellipse correction of the laser beam cross section 510 (making the elliptical shape closer to a circular shape) can be performed.

When the output surface of the wedge prism 130 is made flat, the equiphase front 128 of the output light becomes flat everywhere within the laser beam cross section 510, so the situation in which optical noise cannot be reduced was explained with reference to FIG. 9D(a). In order to achieve the effect of optical noise reduction, in FIG. 9D, the output surface of the predetermined optical member 90 is made into a discontinuous surface (fine step formation), and the equal phase plane 128 of the output light is divided into wavefronts. That is, the laser beam cross section 510 is divided into wavefronts for each plane within the step.

In the embodiment shown in FIG. 9D(b), the output surface 94 of the predetermined optical member 90 has a fine step structure. However, the present invention is not limited thereto, and a fine step structure may be provided on the entrance surface 92 side of the predetermined optical member 90. The predetermined optical member 90 in which the exit surface 94 or the entrance surface 92 has a fine step may be referred to as a multi-segment Fresnel prism 140.

The number of planes for each step in this laser beam cross section 510 corresponds to the number of wavefront divisions. Therefore, as the value of the distance P between adjacent steps decreases, the number of wavefront divisions increases. A mechanical tool cutting technique can be used to form fine steps within the exit surface 94 or the entrance surface 92 of the predetermined optical member 90. Therefore, it is possible to relatively easily form a step with a small distance P between adjacent steps, and the number of wavefront divisions can be significantly increased. As shown in FIG. 8 or FIG. 17B (details will be described later), the optical noise reduction effect improves as the number of wavefront divisions increases. In other words, providing a fine step structure on the entrance surface or exit surface of a predetermined optical member produces the effect of significantly reducing optical noise using a relatively easy method.

The light intensity distribution within the beam size D of the light incident on the predetermined optical member 90 is rarely uniform. In many cases, the light intensity is highest near the center, and decreases as it approaches the periphery. Therefore, if the distance P between adjacent steps is made uniform everywhere, the light intensity of the divided light extracted near the center will increase. Therefore, the value of the distance P between adjacent steps may be changed for each location in accordance with the intensity distribution of light incident on the predetermined optical member 90. Specifically, the value of the distance P between adjacent steps may be made small near the center, and the value of the distance P between adjacent steps may be gradually increased as it approaches the periphery. With such a setting, the light intensity of each divided light (element) extracted for each level difference is made uniform, and the optical noise reduction effect is improved.

When the entrance surface 92 or the exit surface 94 has a fine step structure in this way, a relationship of phase asynchrony 402 (phase discontinuity) is created between the wavefront split lights (elements) extracted between adjacent steps. If it is included, the optical noise reduction effect will be improved. As a condition to satisfy this characteristic,

望ましくは

Preferably

の関係を満足しても良い。数式１３において光路長差ΔＬ_０／２では、隣接段差（隣接する領域）を通過した光（エレメント）間で完全な位相非同期（位相の不連続性）４０２は起きない。しかし光路長差がΔＬ_０／２以上になると両者間の干渉性は大幅に低減するので、光学的雑音低減効果は表れる。

You may be satisfied with the relationship. In Equation 13, when the optical path length difference is ΔL ₀ /2, complete phase asynchronization (phase discontinuity) 402 does not occur between the lights (elements) that have passed through adjacent steps (adjacent regions). However, when the optical path length difference becomes ΔL ₀ /2 or more, the interference between the two is significantly reduced, and an optical noise reduction effect appears.

The value of Pmax described in the above formula is determined based on the mounting dimensions of the light source section 2, the optical measurement section 84, and the optical device 10. Therefore, the value of Pmax is preferably set to 10 m or 1 m, preferably 10 cm.

If the conditions are set so that the predetermined optical member 90 (its entrance surface 92 or exit surface 94) is tilted with respect to the traveling direction of the first light 202 to satisfy any of Equations 9 to 14, the optical path A length difference occurs and optical noise can be effectively reduced. Therefore, if the specific individual embodiments described in Section 3.3 or the basic optical arrangement described in Section 3.1 are used, the optical system within the light source section 2 can be easily miniaturized. Furthermore, since the number of optical components used can be significantly reduced, there is also the effect that the cost of the light source section 2 or the optical device 10 as a whole can be reduced.

When the entrance surface 92 or the exit surface 94 has a fine step structure in this way, the exit surface side perpendicular 98 or the entrance surface side perpendicular 96 is defined as ``the perpendicular for each plane formed between finely divided adjacent steps. ”. For example, in a Fresnel lens, the planes of each step are inclined to each other. Therefore, in this case, the angle of the exit surface side perpendicular 98 or the entrance surface side perpendicular 96 differs for each step.

The line perpendicular to the exit surface side 98 to the first light 202 means a perpendicular line perpendicular to the fine plane through which the first light 202 passes. Thereby, the angle ζ between the first light 202 emitted from the predetermined optical member 90 and the perpendicular to the exit surface side 98 can be defined. Similarly, when a fine step structure is provided in the entrance surface 92 of a predetermined optical member, the perpendicular to each fine plane region within the step boundary may be defined as the entrance surface side perpendicular 96.

As will be described later in Section 5.1 with reference to FIG. 13, when the light traveling direction of each element that has a mutually phase-asynchronous (phase discontinuity) 402 relationship is slightly tilted, the speckle noise reduction effect is improved. Therefore, the amount of inclination of the fine plane area within the step boundary (the corresponding angle of the exit side perpendicular 98 or the incident surface side perpendicular 96) may be changed individually. As a result, the traveling direction after passing changes between the light beams passing through each fine plane area. In FIG. 9D(b), the traveling direction of the first light 202 after passing through the output surface 94 of the predetermined optical member 90 is shown by a solid line arrow, and the traveling direction of the second light 204 is shown by a broken line arrow. The direction of travel is different between the two.

When creating this fine step structure by mechanical cutting, it can be easily created by slightly tilting the cutting angle of the cutting tool for each fine plane area. Therefore, by creating an inclination between the fine plane regions within the step boundary, speckle noise can be effectively reduced using a relatively simple method.

In the fine step structure shown in FIG. 9D(b), the areas between the steps (the area between the boundaries of the steps) are flat. However, the present invention is not limited to this, and the space between the steps may be a curved surface, as in a Fresnel lens. Further, instead of having a fine step structure, the curved surface may have discontinuity (a change in curvature depending on the location or a change depending on the location of the center point of the spherical surface) like a fly's eye lens described later. Furthermore, it is also possible to have a "fine non-uniform characteristic surface" which expands the concept of the above-mentioned discontinuous curved surface. In this case, define the boundary line where the curved surface is discontinuous or the boundary line between uniform characteristic surfaces, redefine the interval between the boundary lines as the distance P between adjacent regions, and satisfy the condition of Equation 13 or Equation 14. The optical arrangement may be made so as to satisfy the above conditions.

FIG. 9E explains the difference in wavefront (equiphase front) characteristics of light passing through a conventional spherical lens or aspherical lens and light passing through a Fresnel lens or fly's eye lens 142.

FIG. 9E(a) shows an example in which the imaging lens 144 is made of a spherical lens or an aspherical lens. The continuity of the equal phase plane 128 is maintained from the light emitting section 470 to the imaging position (α position). Since the phase is the same everywhere within the equal phase plane 128, the phase asynchrony 402 phenomenon does not occur.

FIG. 9E(b) shows an example in which the imaging optical system is configured with a Fresnel lens or a fly's eye lens 142. This fly's eye lens has a structure in which a plurality of spherical lenses or aspheric lenses are arranged on a two-dimensional plane and bonded together. Therefore, discontinuity of the curved surface (curvature) occurs between adjacent spherical lenses or aspheric lenses. Even when a Fresnel lens or fly's eye lens 142 is used, the light emitted from the light emitting section 470 is imaged at the α position.

However, the Fresnel lens or the fly's eye lens 142 has fine steps or discontinuous curved surfaces on the light entrance surface or the light exit surface. Therefore, division of the equal phase plane 128 occurs within the light emitted from the Fresnel lens or the fly's eye lens 142. When the optical path length difference between the divided equiphase planes 128 exceeds the coherence length ΔL ₀ (or twice that), phase asynchronization (phase discontinuity) 402 occurs between the divided equiphase planes 128. do.

In FIG. 9F, a Fresnel lens or Fresnel lens 142 arranged at an angle is used as the predetermined optical member 90. The incident side perpendicular 96 of the predetermined optical member 90 is inclined by an angle θ with respect to the traveling direction of the first light 202 just before reaching the entrance surface 92 of the predetermined optical member 90 . By tilting the predetermined optical member 90 in this way, the optical path length from the light emitting section 470 to the entrance surface 92 of the predetermined optical member 90 is changed for each optical path. Then, the optical arrangement is made such that the difference in optical path length between the lights (first light 202, second light 204, and third light 206) passing through different optical paths exceeds the coherence length ΔL ₀ (or twice that). .

Instead of converting the incident light to the predetermined optical member 90 into parallel light using the collimating lens or the cylindrical lens 120 as shown in FIG. 9F(a), the light incident on the predetermined optical member 90 is converted into parallel light as shown in FIG. 9F(b), and the predetermined optical member is The light may be incident on the member 90. Accordingly, the collimating lens or cylindrical lens 120 becomes unnecessary, and the number of parts is reduced. This has the effect of making the entire optical system smaller and cheaper.

The waveguide element (optical fiber/optical waveguide/light guide) 110 in FIG. 9F(a) corresponds to the light synthesis location 220 in FIG. 9A. Instead of combining different elements to generate a predetermined light 230 using light propagation within the waveguide element (optical fiber/optical waveguide/light guide) 110, a measurement object 22 is used as shown in FIG. 9F(b). You may do so.

It is known that near-infrared light in the wavelength range of 0.8 μm to 2.5 μm has a deep penetration distance into living organisms. Since the inside of a living body has a complex structure (complex and minute refractive index distribution), the near-infrared light that enters the living body undergoes light scattering. In this light scattering process, a photosynthesis process is performed between different elements that are in a phase-asynchronous relationship 402 with each other.

FIG. 9G shows an example of an embodiment in which a light reflective optical member is used as the predetermined optical member 90 that is arranged at an angle with respect to the traveling direction of the first light 202 immediately before incidence. As a specific embodiment of this light-reflecting optical member, in FIG. 9G, a multi-segment light-reflecting element or a Fresnel type reflector 148 is used. However, it is not limited to this, it has light reflection characteristics, and the inside of the light reflection surface has "fine step structure", "finely divided curved surface structure", "discontinuity of the radius of curvature and inconsistency of the center of the curved surface", etc. It is also possible to use an optical member 90 that includes any structure that constitutes a fine non-uniform characteristic surface.

Here, when the multi-segment light reflecting element 148 is used as the light reflecting optical member 90, the distance P between adjacent steps can be defined. In addition, when using a light reflecting surface on which a "fine non-uniform characteristic surface" is formed, the distance between the boundaries where the uniform characteristic surface (including curved surfaces) changes is defined as the distance between adjacent regions P. It may be stipulated. In either case, if the optical arrangement is set so as to satisfy either of the conditions of Equation 13 and Equation 14, the effect of reducing optical noise with respect to the light reflected from the predetermined optical member 90 is produced.

Furthermore, the value of P may be changed between different locations on the predetermined optical member 90 depending on the light intensity distribution of the light incident on the predetermined optical member 90. For example, in the light intensity distribution of incident light, the light intensity may take a maximum value near the center, and the light intensity may decrease at the periphery. In this case, the distance between adjacent steps (distance between adjacent regions) P may be narrowed near the center of the incident light, and the distance P between adjacent steps (distance between adjacent regions) may be widened at the periphery of the incident light. As a result, the light intensity between the light (elements) reflected in each region is brought closer to uniformity, and the optical noise reduction effect is improved.

In FIG. 9G, an Fθ lens or collimating lens 324 is used as an optical element that changes the divergence of the divergent radiation from the light emitting unit 470. The Fθ lens has a characteristic of condensing parallel light incident at an angle θ to different positions on the focal plane. It is given this name because it has the characteristic of focusing light at a position shifted by Fθ with respect to the focal length F of this Fθ lens. A collimating lens basically has the same characteristics, but as the value of Fθ (image height) increases, comatic aberration increases. Therefore, in an optical system where the value of Fθ (image height) is small, a collimating lens can be used instead of an Fθ lens.

Here again, the fine plane within the boundary line of the step is defined as the entrance surface 92 of the predetermined optical member. A perpendicular line perpendicular to the plane corresponds to the entrance surface side perpendicular line 96. In the embodiment shown here, all the normals 96 on the incident surface side are in a parallel relationship within the predetermined optical member 90 (the incident surfaces 92 of all the finely divided predetermined optical members are in a parallel relationship with each other).

An inclination angle θ is formed between the traveling direction of the first light 202 immediately before entering the predetermined optical member 90 and the normal line 96 on the incident surface side. Here, when θ=0, the light reflected by the entrance surface 92 of the predetermined optical member returns to the light emitting point in the light emitting section 470. Therefore, in this embodiment, by setting θ≠0, the light reflected by the entrance surface 92 of the predetermined optical member is focused at a different position from the light emitting section 470. The entrance surface (within the core region 112) of the waveguide element (optical fiber/optical waveguide/light guide) 110 is arranged at this light condensing position. The light passes through a waveguide element (optical fiber/optical waveguide/light guide) 110, and different elements are combined. Therefore, this waveguide element (optical fiber/optical waveguide/light guide) 110 corresponds to the light synthesis location 220 in FIG. 9A.

A light incident surface 92 (light reflecting surface) of the predetermined optical member 90 has a fine step structure formed therein. A plane (or curved surface) obtained by macroscopically averaging this fine step structure is defined as a macroscopic entrance surface 122 of the predetermined optical member. Alternatively, the macroscopic entrance surface 122 of the predetermined optical member may be defined by an upper or lower envelope surface having a fine step structure. A perpendicular line perpendicular to the macroscopic entrance surface 122 of this predetermined optical member is defined as a perpendicular line 126 to the macroscopic entrance surface.
Then, the angle ξ between the traveling direction of the first light 202 immediately before entering the predetermined optical member 90 and the perpendicular line 126 to this macroscopic entrance plane can be defined.

The optical path length difference that occurs between the first light 202 and the second light 204 in the optical system of FIG. This occurs within the optical path leading to the optical waveguide (optical waveguide/light guide) 110. In particular, when a reflective predetermined optical member 90 (multi-segment light reflecting element (Fresnel type reflecting plate) 148) is used, an optical path length difference is created between the outgoing path and the twice the incoming optical path before and after reflection. Therefore, when the predetermined reflective optical member 90 is used, an optical path length difference twice as large as the mechanical arrangement dimension can be obtained. When setting a predetermined optical path length difference by arranging the predetermined optical member 90 at an angle with respect to the traveling direction of the first light 202, using the reflective predetermined optical member 90 has the effect that the optical system can be made smaller. There is.

When the value of this angle ξ is set large, the optical path length from the light emitting section 470 to the macroscopic entrance surface 126 of the predetermined optical member 90 changes greatly depending on the optical path. Therefore, for the reason already explained above, for the light cross-sectional size D immediately before entering the predetermined optical member 90,

または

or

の関係を満足させても良い。数式１５と数式１６に含まれたＬmaxの値は既に説明した理由から、１０ｍ、望ましくは１ｍに設定しても良い。

It is okay to satisfy the relationship of For the reasons already explained, the value of Lmax included in Equations 15 and 16 may be set to 10 m, preferably 1 m.

Incidentally, the light cross-sectional size D immediately before entering the predetermined optical member 90 may be defined by the effective beam diameter of the emitted light from the light emitting unit 470 that can pass through the Fθ lens or the collimating lens 324. However, the present invention is not limited thereto, and the width (half-width or half-value diameter) of a place where the intensity decreases to half of the maximum intensity in the intensity distribution of the light emitted from the light emitting section 470 may be regarded as the optical cross-sectional size D. . Another idea is the width (e ^-2 width or e ^-binary diameter) of the area where the intensity of the light emitted from the light emitting section 470 decreases to e ^-2 , which is the maximum intensity. may be regarded as the optical cross-sectional size D.

Let F be the focal length of the Fθ lens or collimating lens 324. The relationship D=2FNA holds between the optical cross-sectional size D (effective luminous flux diameter) of the parallel light just before it enters the predetermined optical member 90 and the NA value of the Fθ lens or the collimating lens 324. Therefore, using this relational expression, Equation 15 and Equation 16 above become

または

or

と書き換えられる。従ってＦθレンズまたはコリメートレンズで平行光に変換される光学系を使用する場合には、数式１７または数式１８の条件を利用しても良い。この条件を満足した場合には、多分割光反射素子１４８（所定光学部材９０）を経た後の光では光学的雑音が低下する効果が生じる。

It can be rewritten as Therefore, when using an optical system that converts into parallel light using an Fθ lens or a collimating lens, the conditions of Equation 17 or Equation 18 may be used. When this condition is satisfied, the effect of reducing optical noise in the light after passing through the multi-divided light reflecting element 148 (predetermined optical member 90) is produced.

Next, the optical interference between the reflected lights (elements) of each adjacent step (adjacent area) is reduced, and a predetermined light 230 synthesized within the waveguide element (optical fiber/optical waveguide/light guide) 110 is generated. The conditions for reducing optical noise will be explained. When the optical path length difference between the reflected lights (elements) for each adjacent step (adjacent region) becomes ΔL ₀ /2 or more, the optical interference between the two is reduced. Therefore, as the value of the distance between adjacent steps (distance between adjacent areas) P,

望ましくは

Preferably

の条件を満足しても良い。上記の数式内で記載されるＰmaxの値は前述した理由から、１０ｍまたは１ｍ、望ましくは１０ｃｍに設定しても良い。

may satisfy the following conditions. The value of Pmax described in the above formula may be set to 10 m or 1 m, preferably 10 cm, for the reasons mentioned above.

When the semiconductor laser element 500 is used as the light emitting section 470, the emitted laser light cross section 510 often takes an elliptical shape. The reflective predetermined optical member 90 may be tilted in a direction along a plane (the paper plane of FIG. 9G) that includes the long axis direction 78 of this elliptical shape. With this arrangement, not only can the entire optical system be made smaller, but also the number of wavefront divisions in the major axis direction (depending on the number of steps) increases. As a result, the optical noise reduction effect is improved (see FIG. 8).

In the embodiment shown in FIG. 9G, an Fθ lens or a collimating lens 324 is used to make parallel light incident on the predetermined optical member 90. However, the present invention is not limited thereto, and an optical system that does not use the Fθ lens or the collimating lens 324 may be used. In this case, a Fresnel concave mirror (multi-segmented concave mirror) or a concave Fresnel-shaped elliptic curved mirror (multi-segmented elliptic curved mirror) is used as the light reflecting surface of the predetermined optical member 90. When the Fθ lens or the collimating lens 324 is not used, the diverging light emitted from the light emitting section 470 enters the direct reflection type predetermined optical member 90. Therefore, as long as the diverging light incident on the direct reflection type optical member 90 can be focused at one point (such as the entrance of the waveguide element 110) after reflection, the reflection surface shape of the reflection type optical member 90 can be arbitrarily set, not limited to the above. It's okay.

In the embodiment shown in FIG. 9G, the direction in which the microscopic entrance surface 92 of the predetermined optical member is tilted is the same as the direction in which the macroscopic entrance surface 122 of the predetermined optical member is tilted. Accordingly, there is an effect of increasing the light utilization efficiency of the multi-division light reflecting element 148 (predetermined optical member 90). When the condition for making the directions of inclination of both of them match is expressed in a mathematical expression, ξ×θ≧0.

FIG. 9H is an explanatory diagram of the effect regarding the above conditions. When a condition that deviates from the above condition is expressed in a mathematical formula, ξ×θ<0. Under this condition, as shown in FIG. 9H, the stepped side surface is exposed from the direction in which the incident light travels. The reflected light from the exposed side surface of the step becomes a stray light component 146, and the utilization efficiency of the light returning to the waveguide element (optical fiber/optical waveguide/light guide) 110 decreases.

FIG. 9I shows an example application embodiment of FIG. 9G. Therefore, basically, the content explained using FIG. 9G remains valid. When the semiconductor laser element 500 is used as the light emitting section 470, speckle noise is likely to occur. On the other hand, if the irradiation direction toward the measurement object 22 is slightly shifted for each element that has a phase-asynchronous relationship (does not interfere with each other), speckle noise is significantly reduced. Details will be explained in Section 5.1 using FIG. 13.

Therefore, the inclination amounts θ ₁ to θ ₃ are slightly shifted between the incident surfaces 92-1 to 92-3 of the individual predetermined optical members divided by the steps. Let θ ₁ be the angle between the normal line 96-1 on the side of the entrance surface that is perpendicular to the entrance surface 92-1 of the predetermined optical member on which the first light 202 enters, and the traveling direction of the first light 202 immediately before the entrance. . Similarly, the angle between the normal line 96-2 on the incident surface side perpendicular to the incident surface 92-2 of the predetermined optical member on which the second light 204 is incident and the traveling direction of the second light 204 immediately before the incident is θ ₂ shall be. Then, the angle between the normal line 96-3 on the incident surface side that is perpendicular to the incident surface 92-3 of the predetermined optical member on which the third light 206 is incident and the traveling direction of the third light 206 immediately before the incident is θ ₃ . do. The traveling directions of the first light 202, the second light 204, and the third light 206 immediately before incidence are parallel to each other. Therefore, when the incident surfaces 92-1, 2, and 3 are tilted, the relationship is, for example, θ ₁ <θ ₂ <θ ₃ or θ ₁ >θ ₂ >θ ₃ .

A transmissive or reflective diffuser plate 460 is placed on the focal plane of the Fθ lens or collimating lens 324. Each of the entrance surfaces 92-1, 2, and 3 of the predetermined optical member is tilted in accordance with the above conditions. Then, the first light 202 is reflected at the entrance surface 92-1 of the predetermined optical member and then focused at the ρ ₁ position on the diffuser plate 460. Further, the second light 204 is reflected by the entrance surface 92-2 of a predetermined optical member and then focused at the ρ ₂ position on the diffuser plate 460, and the third light 206 is reflected by the entrance surface 92-3 of the predetermined optical member. After that, the light is focused on the ρ ₃ position on the diffuser plate 460.

The optical system in FIG. 9I uses a Koehler illumination system to irradiate the measurement object 22 with light. Therefore, each light (element) that passes through the collimating lens or the imaging lens 450 through different condensing points ρ ₁ , ρ ₂ , ρ ₃ travels in slightly different directions, and is synthesized with the object 22 to be measured. Irradiate light. Further, due to the function of the diffuser plate 460 disposed on the light condensing surface, the respective lights (elements) are mixed with each other (further synthesis is promoted).

A reflecting surface 254 that reflects part of the light is installed immediately in front of the diffuser plate 460 placed on the light collecting surface, and the light reflected here is focused into the photodetecting element 250. The amount of light detected by this photodetector element 250 is fed back to the amount of light emitted by the light emitting section 470.

A light reflecting type diffuser plate 460 may be used as the diffuser plate 460 disposed on the light condensing surface, and this light reflecting type diffuser plate 460 may be tilted. The amount of inclination may be adjusted to cause the light reflected by the light reflecting diffuser plate 460 to travel toward the front of the page. In this case, a collimating lens or an imaging lens 450 is placed in the middle of the optical path traveling toward the front of the page. This optical arrangement has the effect of making it possible to significantly reduce the thickness of the light source section 2.

Furthermore, piezoelectric elements 526 and 528 may be attached to a light-reflecting diffuser plate 460 arranged at an angle as described later in FIG. 27A, and the inclination angle of the light-reflecting diffuser plate 460 may be changed over time. Further, instead of the light reflecting diffuser plate 460, a light reflecting plate 520 connected to the piezoelectric elements 526 and 528 may be installed at the same location. Speckle noise may be further reduced by time-summing or time-averaging the data (or images) for each different tilt angle collected by the measurement unit 8 (see Section 8.2 for detailed speckle noise reduction). (described later).

Note that also in the embodiment shown in FIG. 9I, the arrangement of the Fθ lens or the collimating lens 324 may be omitted, as described in FIG. 9G. In that case, if the entire incident surfaces 92-1 to 92-3 of the reflective predetermined optical member 90 are provided with a macroscopic concave curved surface, the reflected light will be condensed.

Chapter 4 Hybrid Light Source Unit and Its Utilization Form Section 4.1 Relationship between biological components and absorption wavelengths There is no universal light source as an existing light source constituting the light emitting unit 470, and each has its advantages and disadvantages. For example, one existing LED (light-emitting diode) element has a relatively narrow emission wavelength width, so it is not suitable as a stand-alone light source for measuring spectral characteristics. On the other hand, thermal light emitting sources such as halogen lamps have a wide emission wavelength range, but have a problem in that their emission intensity is relatively low.

In this embodiment, a hybrid light source unit that combines a plurality of light emitting elements is used. As a result, the usage of the light source section 2 is expanded, and a variety of services can be provided to users. Safety is extremely important when providing a variety of services to users. Semiconductor laser light and LED light can provide high light intensity, but high light emission intensity in the visible light range has the risk of damaging human eyes.

FIG. 10A shows the relationship between the absorption wavelength of each biological system component 988 in near-infrared light in the wavelength range of 0.9 μm to 1.8 μm. The wavelength range from 1.35 μm to 1.80 μm is called the first overtone region and has a relatively large amount of light absorption. Within this wavelength range, proteins, carbohydrates, and lipids absorb relatively large amounts of light in the order of short wavelengths. Furthermore, the wavelength range from 0.90 μm to 1.25 μm is called the second overtone region, and the amount of light absorption is relatively small. The absorption wavelengths of each biological system component 988 within this wavelength range are arranged in the order of carbohydrates, proteins, and lipids from the short wavelength side. Here, in the wavelength range of 1.35 μm or more, which corresponds to the first overtone region and the combined sound region, it is important to have a characteristic that the amount of moisture absorbed is extremely large. On the other hand, the amount of moisture absorbed is small in the wavelength range of 1.35 μm or less, which corresponds to the second overtone region.

FIG. 10B shows the cross-sectional structure of the human eye. Light entering from the outside world reaches the retina 150 via the crystalline lens 158 and the vitreous body 154. This retinal portion 150 is most likely to be damaged by light irradiation. Here, the crystalline lens 158 and the vitreous body 154 contain a large amount of water. Therefore, light in the wavelength range of 1.35 μm or more, where the amount of moisture absorbed is extremely large, is absorbed within the crystalline lens 158 and the vitreous body 154 and does not reach the retina 150.

For the above reasons, when using semiconductor laser light with high emission intensity, the risk of damage to the eyes can be significantly reduced by setting the wavelength of the semiconductor laser light to 1.35 μm or more. On the other hand, near-infrared light with a wavelength exceeding 1.8 μm (particularly 2.4 μm) is affected by moisture too much. Therefore, when near-infrared light with a wavelength exceeding 1.8 μm (particularly 2.4 μm) is used, there is a risk that the light will be absorbed by water droplets or wetness adhering to the surface of the measurement target 22, resulting in a significant decrease in measurement accuracy. be.

Therefore, in this embodiment, when the measuring section 8 uses reflected light from the measurement object 22 including a human being, and furthermore, a laser emitting element (such as the semiconductor laser element 500) is arranged in the hybrid light source section, The value of the center emission wavelength λ ₀ of the laser emitting device (semiconductor laser device 500, etc.) is set to 1.35 μm or more and 2.4 μm or less (preferably 1.8 μm). This has the effect of ensuring high measurement accuracy while reducing the risk of damage to the eyes.

The optical characteristics shown in FIG. 10A provide important information for measuring the inside of a living body. For example, an example will be explained in which the spectral characteristics of light transmitted through a living body such as a fingertip with a thickness of about 1 cm were investigated. Light with a wavelength of 1.35 μm or less (light scattered within a living body) passes through a living body approximately 1 cm thick, and the characteristics of the transmitted light can be detected as a signal. In comparison, light with a wavelength exceeding 1.35 μm is absorbed by the water in the living body, and almost no signal can be detected as transmitted light. This situation almost matches the optical absorption wavelength dependence of water shown in FIG. 10A. Therefore, in this embodiment for measuring the characteristics inside a living body, the wavelength of the light emitted from the hybrid light source section is set to 1.35 μm or less.

Furthermore, when measuring using light in the second overtone region shown in FIG. 10A, relatively high precision measurement is possible. As can be seen from FIG. 10A, the measurement wavelength suitable for the second overtone region is 0.9 μm or more. Therefore, in this embodiment, when measuring the characteristics inside a living body, the wavelength of the light emitted from the hybrid light source section is set to 0.9 μm or more and 1.35 μm or less.

Next, the role of laser light in this embodiment will be described when measuring characteristics inside a living body using a hybrid light source section in which a laser light emitting element (semiconductor laser element 500, etc.) is disposed. Laser light has a high emission intensity but a narrow emission wavelength width, so it is not suitable for measuring spectral characteristics alone. Therefore, in this embodiment, the object to be measured using light of a specific wavelength inside a living body may be used, for example, for measurements involving temporal changes such as pulsation and respiration measurement.

Additionally, when simultaneously measuring the spectral characteristics inside a living body using light emitted from another light source installed inside the hybrid light source, it is necessary to devise a way to prevent the laser light wavelength from interfering with the spectral characteristics measurement. As described above, measurement in the second overtone region is suitable for the spectral characteristics inside the living body using light emitted from this other light source. As shown in FIG. 10A, the longest wavelength absorbed by lipids in the second overtone region is around 1.25 μm. Therefore, in this embodiment, the laser light wavelength that does not impede this spectral characteristic measurement may be set to 1.25 μm or more. The results of the above study can be summarized as follows. That is, when measuring the characteristics inside a living body using the hybrid light source in this embodiment, the emission wavelength range of the laser light emitting device (such as the semiconductor laser device 500) installed in the hybrid light source should be 1.25 μm or more and It may be set to 1.35 μm or less.

Section 4.2 Example of Internal Structure of Hybrid Light Emitting Unit FIG. 11A shows an example of internal structure of the hybrid light emitting unit 470 in this embodiment. As explained in the previous section, measurement of spectral characteristics inside a living body requires a measurement wavelength range of 0.9 μm to 1.25 μm using the second overtone region. Therefore, it is desirable to emit light in a wide wavelength range of 0.9 μm to 1.3 μm, which is the measurement wavelength range plus a margin. However, it is difficult to achieve light emission in such a wide wavelength range with a single existing LED light source.

In order to realize light emission in the above-mentioned wide wavelength range, this embodiment uses phosphors 162 and 164 that emit near-infrared light. Then, a phosphor 162 that emits near-infrared light whose center fluorescence wavelength is on the short wavelength side and a phosphor 164 that emits near-infrared light whose center fluorescence wavelength is on the long wavelength side are stacked. Then, as the sum of the emission characteristics from the individual near-infrared light-emitting phosphors 162 and 164, near-infrared fluorescence light 178 emitting fluorescence in the wavelength range of 0.9 μm to 1.3 μm is obtained.

This laminated structure is then fixed within a transparent sealing area 166 made of transparent resin. Furthermore, the outside of this transparent sealing area 166 is surrounded by a waterproof coating layer 168 containing a material with low moisture permeability such as polyethylene, transparent silicone, transparent Teflon (registered trademark), or the like. The action of this waterproof coating layer 168 prevents moisture contained in the outside world from entering into these phosphors 162 and 164.

Inside this hybrid light emitting section 470, two light emitting sources 160 and 170 are arranged, and a common electrode 174 is shared for power sharing. Emitted light from an LED light source as a first light source 160 excites near-infrared light emitting phosphors 162 and 164. Therefore, the emission wavelength of this excitation LED light source must be shorter than the fluorescence wavelength emitted in the range of 0.9 μm to 1.3 μm. An LED light source having an appropriate emission wavelength within the range of 600 nm to 900 nm is selected in accordance with the characteristics of the near-infrared light emitting phosphors 162 and 164.

A semiconductor laser light source (semiconductor laser element 500) may be used as the second light emitting source 170. The second light emitting source 170 may have a longer emission wavelength than the fluorescence wavelength (emission wavelength) of the near-infrared light emitting phosphors 162 and 164. As a result, the emitted light 176 from the second light emitting source 170 passes through the near infrared light emitting phosphors 162 and 164 without affecting the near infrared light emitting phosphors 162 and 164, and the hybrid light emitting section 470 It can be effectively used outside of.

Although not shown in FIG. 11A, two photodetectors may be placed in the hybrid light emitting section 470 to monitor the respective amounts of light emitted from the first and second light sources 160 and 170. . By applying feedback to the individual light emission amounts using this photodetector, the light emission amounts from the first and second light sources 160 and 170 can be stabilized.

Section 4.3 Material and structure of near-infrared emitting phosphor and its production method
We will begin with an explanation of phosphor materials that emit near-infrared light. In this embodiment, the phosphor material contains atoms or ions belonging to rare earth elements or transition elements. By using this phosphor material, we obtain fluorescent properties that emit near-infrared light. As a specific embodiment, when an inorganic crystal (oxide crystal) containing a tetravalent chromium ion or a trivalent chromium ion belonging to a transition element was used as a material, the maximum emission wavelength appeared within the wavelength range of 1030 nm to 1350 nm.

An embodiment in which the phosphor material contains atoms or ions belonging to rare earth elements will be described. When trivalent ytterbium ion Yb ³⁺ was used as the rare earth element, the maximum emission wavelength appeared in a wavelength band around 1 μm. Furthermore, when trivalent neodymium Nd ³⁺ was used, maximum emission wavelengths appeared in the wavelength bands of 0.9 μm, 1.06 μm, and 1.3 μm, respectively. When trivalent samarium Sm ³⁺ was used, fluorescence emission was observed in a wide wavelength band of 0.85 μm to 1.2 μm.
Furthermore, trivalent erbium Er ³⁺ or trivalent praseodymium Pr ³⁺ may be used as atoms or ions belonging to rare earth elements. Furthermore, the present embodiment is not limited thereto, and atoms or ions belonging to any rare earth element or transition element may be used for the phosphor material.

FIG. 11B shows the detailed structure inside the near-infrared emitting phosphors 162 and 164 in this embodiment. In the binder region 180, fluorescent substances 182 to 186 having different particle sizes (having a predetermined particle size distribution) are dispersed. For the binder region 180, a glass material such as glass SiO ₂ or bismuth oxide Bi ₂ O ₃ or antimony oxide Sb ₂ O ₃ may be used. Furthermore, the material for forming the binder region 180 is not limited thereto, and epoxy resin, acrylic resin, or silicone resin may be used.

The fluorescent material 182 contains any of the atoms or ions A belonging to the rare earth elements or transition elements described above. In the fluorescent substance 184, B is an atom or an ion belonging to a rare earth element or a transition element different from A. Further, the fluorescent substance 186 contains an atom or an ion C belonging to a rare earth element or a transition element different from the above A and B. As explained above, the different atoms or ions A, B, and C have different central emission wavelengths when emitting fluorescence. Therefore, when fluorescent substances 182 to 186 containing different atoms or ions A, B, and C are mixed together, an effect of emitting fluorescence in a wide wavelength range is produced as near-infrared emitting fluorescent substances 162 and 164.

The center wavelength of the fluorescence emission for each type of ion explained above corresponds to the fluorescence emission that occurs inside a relatively large lump. However, when the same ion exists near the surface, the energy levels of electron orbit change slightly, causing a shift in the central emission wavelength. Furthermore, when the fluorescent substances 182 to 186 are formed into fine particles with a particle size of about 3 μm to 10 μm, interaction between lattice vibrations (interatomic vibrations) within the fine particles and electron orbital levels occurs. Therefore, when the particle size of the fluorescent substances 182 to 186 changes, the center wavelength of fluorescence emission changes. In the present embodiment, taking advantage of this situation, the fluorescent substances 182 to 186 contained in the near-infrared emitting phosphors 162 and 164 have a wide particle size distribution. By mixing the fluorescent substances 182 to 186 with greatly different particle sizes in this way, the effect of greatly expanding the wavelength range in which fluorescence is emitted is created.

In this embodiment, the average particle size of the fluorescent substances 182 to 186 is set within the range of 0.5 μm to 100 μm for ease of manufacture. The particle size distribution range of the fluorescent substances 182 to 186 in this embodiment is defined by the ratio range of the maximum particle size and the minimum particle size of the fluorescent substances 182 to 186 contained in the same near-infrared emitting phosphors 162 and 164. .

The minimum particle size in the fluorescent substance 182 containing atoms (or ions) A belonging to rare earth elements or transition elements is defined as D _A min and maximum particle size D _A max, and the ratio between them is N _A ≧ D _A max/ Manufacture control is carried out so that D _A min ≧ _MA falls within the range. Similarly, the minimum particle size in the fluorescent substance 182 containing atoms (or ions) B belonging to rare earth elements or transition elements is defined as D _B min and maximum particle size D _B max, and the ratio between them is N _B ≧ D _B Manufacture control is performed so that max/D _B min≧ _MB falls within the range. Further, the minimum particle size in the fluorescent material 182 containing atoms (or ions) C belonging to rare earth elements or transition elements is defined as D _C min and maximum particle size D _C max, and the ratio between them is N _C ≧ D _C max. /D _C min≧M _C Manufacture control is carried out so that the range is within the range.

After various checks, it was found that the values of _MA , _MB , and _MC are all 1.5, preferably 4. It has also been found that the values of _NA , _NB , and _NC are all 1000 or 100, preferably 10.

FIG. 11C shows a method for manufacturing the near-infrared emitting phosphor in this embodiment. Start of production of near-infrared emitting phosphor At the beginning of ST01, lumps of fluorescent material each containing atoms (or ions) A/B/C belonging to a rare earth element or a transition element shown in step 02 are created.

For example, when creating a lump of fluorescent material containing atoms (or ions) of rare earth elements such as ytterbium, neodymium, and samarium, powders of their oxides Yb ₂ O ₃ , Nd ₂ O ₃ , and Sm ₂ O ₃ are used. prepare. Further, powders of glass SiO ₂ , bismuth oxide Bi ₂ O ₃ , and antimony oxide Sb ₂ O ₃ are prepared as inorganic materials (oxide materials) to be mixed with these materials. When these are mixed individually and kept at a temperature of 1,250°C for about 10 minutes, they melt to form a lump of fluorescent material.

In the next step 03, this lump is crushed and powdered. This powder is finely ground until the average particle size of each fluorescent substance contained in the powder is about 3 μm to 10 μm. As described above, the fluorescence emission intensity distribution characteristics of the near-infrared emitting phosphors 162 and 164 in the wavelength direction are greatly influenced by the particle size distribution of the phosphors. Therefore, the powder obtained by pulverization is subjected to particle size selection using a sieve with a uniform mesh size. First, the pulverized powder is passed through a sieve with a large mesh size to remove fluorescent substances with non-standard particle sizes. Next, the mesh size of the sieve is gradually reduced to sequentially select fluorescent substances whose particle size falls within a predetermined range. In this way, fluorescent substance powders 182 to 186 having a predetermined particle size distribution are extracted (ST04).

In step 05, fluorescent material powders 182 to 186 having respective particle size distributions and a liquid or powder binder 180 are blended. Next, this liquid or powdered binder 180 is solidified (hardened or coagulated) (ST06), and the production of the near-infrared emitting phosphor is completed (ST07). When a glass material is used as the binder 180, the powdered glass material and the fluorescent substance powders 182 to 186 are mixed and then heated to a high temperature to harden the mixture. If an organic material such as an epoxy resin or a silicone resin is used as the binder 180, it is left for a specific period of time until it is cured by the action of a curing agent. Further, when an acrylic photocurable resin is used as the binder 180, it may be cured by ultraviolet irradiation.

Section 4.4 Embodiment in which the light source section and measurement section are integrated and miniaturized The hybrid light emitting section 470 explained in Section 4.3 using FIG. 11A and Section 3.3 using FIGS. 9F(a) and 9G FIGS. 12A and 12B show a structure in which the optical arrangement in the light source section 2 and the measurement section 8 that performs spectroscopic measurement are integrated and miniaturized. In both the embodiments shown in FIGS. 12A and 12B, the hybrid light emitting section 470 described in Section 4.3 is used as the light emitting section 470.

Both of the embodiments shown in FIGS. 12A and 12B use a spectroscopic element 320 using a reflective blazed grating to measure spectral characteristics. The light of each measurement wavelength separated by the spectroscopic element 320 is focused on the line sensor 300, which is composed of a one-dimensionally arranged photodetection cell array.

12A differs from FIG. 9F(a) in that the light after passing through the predetermined optical member 90 is focused on the surface of the measurement target 22. In FIG. That is, a folding mirror plate 314 is installed immediately before the condensing position of the light after passing through the predetermined optical member 90, and is folded back toward the back side of the page. After that (not shown), the light is focused on the surface of the measurement object 22 installed on the back side of the paper.

As explained in Section 4.1, the emitted light from this hybrid light emitting unit 470 enters the living body and is repeatedly reflected diffusely within the living body. A part of the light diffusely reflected within the living body exits the surface of the measurement object 22 (living body surface). A portion of the light emitted from the surface of the measurement object 22 (living body surface) passes through the pinhole 310. The light passing through the pinhole 310 is reflected by the half mirror plate 312 and becomes parallel light through a collimating lens or Fθ lens 322.

Since the spectroscopic element 320 is slightly tilted, the light reflected by the spectroscopic element 320 passes through the upper part of the half mirror plate 312 and reaches the line sensor 300.

By bending the optical path in the middle using the folding mirror plate 314 and the half mirror plate 312 in this way, an effect is created in which the integrated structure of the light source section 2 and the measuring section 8 can be made thinner.

The structure of the example embodiment shown in FIG. 12A may not be used, but the optical arrangement of FIG. 9F(b) in which the collimating lens or cylindrical lens 120 is removed may be used.

A part of FIG. 12B uses the same optical arrangement as FIG. 9G, and also bends the optical path with two folding mirror plates 314 and 316 similarly to FIG. 12A, making it possible to reduce the thickness. The Fθ lens or collimating lens 324 used in FIG. 12B may be omitted, and the light reflecting surface of the reflective predetermined optical member 90 may be made into a concave curved surface instead. This results in a reduction in the number of optical parts, which has the effect of making the optical system more compact and lower in price.

Chapter 5 Other embodiment examples for optical noise reduction Section 5.1 Features of speckle noise pattern
FIG. 13(a) shows the basic principle of generating speckle noise, which is a type of optical noise. Two light reflecting regions 1046 are arranged at a distance P apart from each other. FIG. 13A shows the reflection intensity of reflected light 1048 that is vertically incident on the light reflection region 1046 and reflected in the θ ₀ direction. According to the theory of light interference, the reflected intensity at that time is proportional to cos ² (πPθ ₀ /λ). What is important here is that the reflection intensity changes periodically in the reflection direction θ ₀ of the reflected light 1048. This periodic change in reflection intensity is related to speckle noise.

Further expanding FIG. 13, consider a case where a plurality of light reflection areas 1046 are regularly arranged with a period P. When the position of the user's eyes observing the reflected light 1048 is fixed, the reflection direction θ ₀ that enters the user's eyes changes for each reflection location within the plurality of light reflection regions 1046. Therefore, there are areas where the reflection amplitudes from adjacent light reflection areas 1046 reinforce each other and appear bright, and areas where the reflection amplitudes cancel each other out and appear dark. This kind of appearance is called a speckle noise pattern.

FIG. 13(b) shows the reflection intensity of the reflected light 1048 reflected in the θ ₀ direction when the angle of incidence of the incident light 1042 on the two light reflection regions 1046 changes to θ _i . According to the theory of light interference, the reflected intensity at that time changes as cos ² {πP(θ ₀ −θ _i )/λ}.

As explained in Section 2.3 using FIG. 7C, light synthesis between different wave trains corresponds to intensity addition (synthesis of light intensity values) because different wave trains do not interfere with each other. For example, as shown in FIG. 13(a), the first light 202 including a part of at least one wave train is vertically incident on the two light reflection regions 1046. At the same time, second light 204 including at least a part of another wave train that does not optically interfere with the wave train is made incident at an incident angle θ _i as shown in FIG. 13(b). Then, the light intensity of the combined light (intensity-added light) reflected in the θ ₀ direction is given by cos ² (πPθ ₀ /λ)+cos ² {πP(θ ₀ −θ _i )/λ}. For example, if the value of θ _i is optimized so that the light intensity of the second term is the minimum when the light intensity of the first term is maximum in the previous equation, the maximum and minimum light intensities will be canceled out (averaged or smoothed). . As a result, speckle noise (optical noise) is significantly reduced.

In other words, consider a situation where the first light 202 and the second light 204 do not interfere with each other (or have a small amount of interference) due to their mutual phase asynchronous (phase discontinuous) relationship. Speckle noise (optical noise) is reduced when the first light 202 and the second light 204 are simultaneously irradiated onto the measurement object 22 with different irradiation angles.

In FIG. 13, in order to simplify the explanation, the intensity addition of only two beams 202 and 204 that are incoherent (or low coherent) with each other is explained. However, the present invention is not limited thereto, and three or more types (or four or more types) of light 202, 204, and 206 that have a non-interfering relationship with each other may be irradiated simultaneously onto the measurement target 22 by changing the irradiation angle. Increasing the number of irradiated lights that are incoherent with each other (or have low coherence) increases the number of averaged speckle noises (optical noises), which increases the speckle noise (optical noise) reduction effect. do.

FIG. 14A shows an example embodiment illustrating an optical arrangement that utilizes the principles described above to reduce spec noise (optical noise). A phase characteristic conversion element 1050 such as a diffuser plate is used as a method of overlappingly irradiating the light irradiation target 1030 with the respective lights 202, 204, and 206 that have passed through different regions 212, 214, and 216 while changing the irradiation angle. Since the surface of the phase characteristic conversion element 1050 has fine irregularities, light passing therethrough is diffused. Then, the irradiation angle to an arbitrary position on the light irradiation target 1050 changes as θ ₁ , θ ₂ , and θ ₃ for the first light 202 , the second light 204 , and the third light 206 . At the same time, the first light 202, the second light 204, and the third light 206 are irradiated in an overlapping manner at this position.

Since the respective irradiation angles are different, the pattern of speckle noise (optical noise) appearing on the light irradiation target 1050 is different between the first light 202, the second light 204, and the third light 206. Since the first light 202, the second light 204, and the third light 206 have a non-interfering (or low-interfering) relationship, different speckle noise patterns are mixed together on the light irradiation target 1030. As a result, the speckle noise pattern is averaged (smoothed), and the overall amount of speckle noise (optical noise amount) is reduced.

Consider now the correspondence between FIG. 14A and FIG. 9A. As described above, the first light 202, the second light 204, and the third light 206 are irradiated onto the surface of the light irradiation target 1050 in an overlapping manner. Therefore, the surface of this light irradiation object 1050 corresponds to the photosynthesis site 220. Furthermore, it is considered that the surface of this light irradiation target 1050 also serves as the entrance surface 92 of the predetermined optical member. Then, the perpendicular line perpendicular to the surface of the light irradiation object 1050 corresponds to the incident surface side perpendicular line 96. As shown in FIG. 14A, the distance between the traveling directions of the first light 202, the second light 204, and the third light 206 and the normal line 96 on the incident surface side, which travel toward the light irradiation target 1050, is θ ₁ , It has angles of θ ₂ and θ ₃ . As is clear from FIG. 14A, regarding the angle θ ₁ generated between the traveling direction of the first light 202 and the normal line 96 on the incident surface side, the relationship θ ₁ ≠0 holds true.

FIG. 14B shows an application example of this embodiment. In FIG. 14B, lights 202, 204, and 206 that do not interfere with each other (or have low interference) are focused at spatially different positions. When the Keller illumination system 1026 is adopted as the illumination system for the light irradiation target 1030, the lights 202, 204, and 206 focused at different positions mix (overlap) with each other and are illuminated at any arbitrary position within the light irradiation target 1030. is irradiated. Further, the irradiation angles at this time are different from each other. As a result, the speckle noise pattern is averaged (smoothed) and the overall speckle noise (optical noise) is reduced.

As a method of focusing the lights 202, 204, and 206 that do not interfere with each other (or have low interference) at spatially different positions, in FIG. 14B, a fly-eye lens 1028 in which lenses with multiple optical axes are arranged in the same space is used. I am using it. In FIG. 14B(a), this fly-eye lens 1028 is placed immediately after the optical characteristic conversion element 210. Further, in FIG. 14B(b), this fly's eye lens 1028 is placed immediately in front of the optical property conversion element 210 and is integrally formed with the optical property conversion element 210.

In both FIG. 14B(a) and FIG. 14B(b), the third, second, and first lights 206, 204, and 202 that have passed through the third, second, and first regions 216, 214, and 212 individually. are focused on the α, β, and γ positions, respectively. By employing the Keller illumination system 1026, the lights 206, 204, and 202 after passing through each condensing position are mixed together and irradiate the light irradiation target 1030 with different irradiation angles.

In the example of FIG. 14B, a fly's eye lens 1028 is used as a method for focusing the light beams 206, 204, and 202 passing through different regions 216, 214, and 212 at different positions α, β, and γ. However, the light is not limited to this, and the light may be focused at different positions α, β, and γ using any other method. In other example embodiments, a liquid crystal lens array may be used in place of fly's eye lens 1028.

As an application example of this embodiment, a bundle fiber 1040 may be used instead of using a single core fiber. FIG. 14C(a) shows an application example using bundle fiber 1040. The light source section 2 includes a light emitting section 470 and an optical characteristic converting section 480. The first light 202 and the second light 204 that are non-interfering with each other (or have low coherence) exiting the light source section 2 are irradiated onto the measurement object 22 by the Keller illumination system 1026. The focal length of the collimating lens 318 installed in this Keller illumination system 1026 controls the value of the difference in the irradiation angle between the first light 202 and the second light 204 irradiated onto the measurement object 22 . That is, when the focal length of the collimating lens 318 is short, the difference in the irradiation angle between the two becomes large.

In the optical property conversion element 210 disposed in the optical property conversion section 480, the first region 212 and the second region 214 have different thicknesses. If the optical path length difference between them exceeds the coherence length ΔL ₀ (or twice that), the coherence between the first light 202 and the second light 204 decreases.

The condensing lens 314 condenses the first and second lights 202 and 204 onto the incident surface of the bundle fiber 1040. Here, first light 202 and second light 204 each enter different core regions within bundle fiber 1040. Due to the combination of the difference in the core region through which the light passes and the collimator lens 318, the traveling direction between the light beams 202 and 204 emitted from the bundle fiber 1040 changes.

In comparison with FIG. 14C(a), FIG. 14C(b) shows an optical system in which a phase characteristic conversion element 1050 is arranged just before the incident surface of the bundle fiber 1040. The first and second lights 202 and 204 that have passed through the phase characteristic conversion element 1050 have their phase characteristics converted and enter the bundle fiber 1040. Specifically, as this phase characteristic conversion element 1050, a diffuser plate having a fine structure on its surface, such as ground glass, may be used. Furthermore, the present invention is not limited to this, and a grating, a hologram element, a Fresnel zone plate, etc. may be used.

In FIG. 14C(c), compared to FIG. 14C(b), the phase characteristic conversion element 1050 is arranged near the convergence plane of the first light 202 and the second light 204. In FIGS. 14C(a) and 14C(b), the first light 202 and the second light 204 mainly pass through different core regions within the bundle fiber 1040. In comparison, in FIG. 14C(c), the first light 202 and the second light 204 mix with each other when passing through the phase characteristic conversion element 1050. As a result, the first light 202 and the second light 204 pass through the same core region within the bundle fiber 1040.

FIG. 14D shows the results of an experiment to confirm the effect actually performed. The horizontal axis in FIG. 14D represents the position on the measurement target. Further, the vertical axis in FIG. 14D represents the measured light amount. When the amount of speckle noise is large, the amount of variation in the measured light amount appears large. As the object to be measured 22, a diffuser plate having an Ra value of 2.8 μm, which represents the average height of surface irregularities, was used.

FIG. 14D(a) shows the measurement results of the speckle pattern when the measurement target 22 is irradiated with conventional light that has passed through the core region within the single-core optical fiber or the center within the light guide 330/332/340. In FIG. 14D(a), the light intensity fluctuates greatly, and large speckle noise appears.

FIG. 14D(b) shows the measurement results of the speckle pattern when the optical system of FIG. 14C(b) is employed. The optical conversion element 210 is made of quartz glass, and is divided into 48 elements each having a thickness different by 1 mm. As the phase characteristic conversion element 1050, a diffusion plate having an Ra value of 0.5 μm was used. The length of the bundle fiber 1040 was 1.5 m, and 320 optical fibers each having a core diameter of 230 μm and an NA of 0.22 were bundled within a range of 5 mm in diameter. The focal lengths of the condensing lens 314 and the collimating lens 318 were both set to 50 mm. Compared to FIG. 14D(a), optical interference noise (speckle noise) in FIG. 14D(b) is significantly reduced.

Section 5.2 Characteristics of various optical fibers and characteristics of light passing through the core region In Section 5.2, we will explain the characteristics of various optical fibers and the characteristics of light passing through the core region 112 of the optical fiber. . In the next section 5.3, a speckle noise reduction method using this characteristic will be explained. First, we will explain the difference between single mode fiber and multimode fiber within the same single core fiber.

FIG. 15A(a) shows the characteristics of a single mode fiber. A cladding region 114 made of a material with a relatively low refractive index is arranged so as to surround the core region 112 with a relatively high refractive index. Here, when the refractive index of the core region is represented by n ₁ and the refractive index of the cladding region is represented by n ₂ , there is a relationship of n ₁ >n ₂ .

The optical amplitude distribution of light propagating within the core region 112 of this single mode optical fiber shows the characteristics on the right side of FIG. 15A(a). That is, the light amplitude takes a maximum value near the center of the core region 112, and decreases as it approaches the periphery within the core region 112. The amplitude distribution of light (mode of amplitude distribution) or electric field distribution 152 within this core region 112 is referred to as a "fundamental mode."

The value of the minimum wavelength λ _C of light propagating within the core region 112 when the characteristics shown on the right side of FIG.

の関係が有る事が知られている。従ってコア領域１１２内を伝搬する任意の光の波長λに対してシングルモードファイバとなる条件は、

It is known that there is a relationship between Therefore, the conditions for a single mode fiber for any wavelength λ of light propagating within the core region 112 are as follows:

となる。つまりコア領域内の直径Ｄが数式２２の条件を満足する小さな値を取る場合には、コア領域１１２内で基本モードを形成する。

becomes. In other words, when the diameter D within the core region takes a small value that satisfies the condition of Equation 22, a fundamental mode is formed within the core region 112.

However, when the diameter D in the core region becomes larger than the condition of Equation 22, the amplitude distribution (amplitude distribution mode) of light in the core region 112 takes on a different amplitude distribution from the amplitude distribution on the right side of FIG. 15A. become. An optical fiber in which an amplitude distribution (another mode) other than the fundamental mode can be formed within the core region 112 is called a multimode fiber. Here, modes (amplitude distribution) other than the above-mentioned fundamental mode are referred to as "higher-order modes." Using the relationship in Equation 22 above, the conditions for the multimode fiber are:

で与えられる。本実施形態例では次の５．３節で説明するように、コア領域１１２内で発生する基本モード以外のモードを利用してスペックルノイズ（光学的雑音）を低減する。従って本実施形態例が実行可能な条件として、図２３式を満足する必要が有る。

is given by In this embodiment, speckle noise (optical noise) is reduced by using modes other than the fundamental mode generated within the core region 112, as described in the next section 5.3. Therefore, as a condition for implementing this embodiment, it is necessary to satisfy the equation shown in FIG.

FIG. 15A(b) shows a method of focusing light within the core region 112. A focusing lens 330 focuses the light into the core region 112. Here, due to the wave nature of light, the focused spot has a width d. Between the half value θ of the aperture angle of the condensing lens 330 and the wavelength λ of the condensed light,

の関係が有る。ここでＤ<<ｄで集光スポットの外側がコア領域１１２からはみ出すため、光の利用効率が低下する。本実施形態では充分に大きな光利用効率を確保するため、

There is a relationship between Here, when D<<d, the outside of the condensed spot protrudes from the core region 112, resulting in a decrease in light utilization efficiency. In this embodiment, in order to ensure sufficiently high light utilization efficiency,

の条件を追加する。そしてこの数式２５を変形すると、

Add the condition. And if we transform this formula 25, we get

の関係が成立する。

The relationship holds true.

Figure 15B shows the characteristics of two types of optical fibers. The right side of FIG. 15B shows the refractive index distribution 138 within the core region 112 and in the cladding region 114. Here, the vertical axis indicates the position 124 within the optical fiber cross section. The optical fiber shown in FIG. 15B(a) is a step-index (SI) type optical fiber in which the refractive index within the core region 112 is uniform throughout. Further, the optical fiber shown in FIG. 15B(b) is a grade index GI (graded index) type optical fiber. The central portion of the core region 112 of this GI type optical fiber has a high refractive index, and the peripheral portion has a low refractive index. In this embodiment, either SI type or GI type optical fiber may be used.

In both the SD type and GI type optical fibers, the limit θmax of the convergence angle of light that can pass through the core region 112 is determined. That is, when light is focused by the condensing lens 330 in FIG. 15A(b), light exceeding θmax as the value of half-maximum θ of the aperture angle cannot be totally reflected at the interface between the core region 112 and the cladding region 114. Become. Therefore, this light jumps out of the optical fiber from the core region 112 via the cladding region 114, as indicated by the dashed arrow in FIG. 15B.

The sine function value sin(θmax) of θmax at this time is defined as the NA value of the optical fiber. And as a condition that this NA value satisfies,

が成り立つことが知られている。この数式２７を数式２３に代入すると、

is known to hold true. Substituting this formula 27 into formula 23, we get

が得られる。次の５．３節で説明する本実施形態を実現する条件として、先に説明した数式２３の代わりに上記数式２８を使用しても良い。コア領域１１２の屈折率ｎ_１とクラッド領域１１４の屈折率ｎ_２は、光ファイバにより異なる。それに比べて光ファイバの仕様内にＮＡ値が一般的に明記されている。従って数式２８を使用すると、汎用性が高く、光学設計が容易になる効果が有る。

is obtained. As a condition for realizing this embodiment described in the next section 5.3, the above-mentioned formula 28 may be used instead of the previously explained formula 23. The refractive index n ₁ of the core region 112 and the refractive index n ₂ of the cladding region 114 differ depending on the optical fiber. In comparison, the NA value is generally specified within the specifications of the optical fiber. Therefore, use of Equation 28 has the effect of providing high versatility and facilitating optical design.

Equation 28 shows the conditions under which higher-order modes can occur within the core region 112. Therefore, the condition under which only the fundamental mode occurs in the core region 112 is given by an expression obtained by reversing the direction of the inequality sign in Equation 28. Also, as a condition for the incident angle θ for light propagation within the core region 112,

が常に成り立つ。この数式２９の関係を利用すると、コア領域１１２内に基本モードしか発生しない条件として

always holds true. Using the relationship of Equation 29, the condition for only the fundamental mode to occur in the core region 112 is

が成立すると予想される。

is expected to hold true.

Section 5.3 Speckle Noise Pattern Reduction Method Using Mode Characteristics in an Optical Fiber Explain the relationship between First, the relationship between FIG. 15C and FIG. 9A will be explained. The inside of the core region 112 of the optical fiber corresponds to the predetermined optical member 90 . Further, the inside of the core region 112 also serves as a photosynthesis site 220. The entrance surface of the optical fiber (inner core region 112) corresponds to the entrance surface 92 of the predetermined optical member. Further, when the optical fiber has a structure in which the entrance surface is cut vertically, the optical axis direction of the optical fiber (inner core region 112) is parallel to the normal line 96 on the entrance surface side. Then, the first light 202 and the second light 204 are identified among the incident lights having different incident angles θ to the core region 112.

FIG. 15C(a) shows a state in which the second light 204 enters the core region 112. The second light 204 enters the core region 112 from a direction substantially parallel to the normal line 96 on the incident surface side. Also, consider the case where the second light 204 is incident at approximately the center of the core region 112 at this time. At this time, the incident angle θ (the angle between the incident direction of the second light 204 and the normal to the incident surface side 96) satisfies the condition of Equation 30. Therefore, the electric field distribution 152 of the second light 204 within the core region 112 forms a fundamental mode (TE (transverse electric) 1).

FIG. 15C(b) shows a state in which the first light 202 enters the core region 112. As explained with reference to FIG. 9A, the first light 202 and the second light 204 travel in different directions just before the entrance surface 92 of the predetermined optical member (here, an optical fiber) 90, so Regarding the incident angle θ of the first light 202 (the angle between the incident direction of the first light 202 and the normal to the incident surface side 96), the relationship θ≠0 holds true. However, consider a case where the first light 202 passes through the center of the core region 112 on the entrance surface 92 of the predetermined optical member (the entrance surface of the core region 112).

In FIG. 15C, when a multimode fiber is used (although either the SI type or the GI type may be used), Equation 28 (or Equation 23) holds true regarding the diameter D of the core region 112. Furthermore, in order to ensure high light utilization efficiency at this time, the incident angle θ of the first light 202 is set so as to satisfy Equation 26 (or Equation 25). Here, this incident angle θ needs to satisfy the condition of Equation 29. Therefore, regarding the incident angle θ range of the first light 202,

と記述できる。本実施形態では第１の光２０２の入射角θを第２の光の入射角より大きく設定して、コア領域１１２内で第２の光と異なる電場分布モード（高次モード）を形成させる。

It can be written as In this embodiment, the incident angle θ of the first light 202 is set to be larger than the incident angle of the second light, so that an electric field distribution mode (higher-order mode) different from that of the second light is formed within the core region 112.

As shown on the right side of FIG. 15C(b), the electric field value of the TE2 mode within this higher-order mode becomes 0 at the center of the cross-sectional position 132 in the core region 112. The polarity of the electric field is reversed in the direction in which the cross-sectional position 132 within the core region 112 is shifted.

The difference between the fundamental mode (TE1 mode) and TE2 mode within the core region 112 appears in the difference in the intensity distribution characteristics of the light emitted from the optical fiber. For example, when the second light 204 propagates in the fundamental mode (TE1 mode) within the core region 112, the light cross-sectional intensity distribution (Far Field pattern) at a location away from the emission location from the optical fiber is The intensity distribution is bright and the periphery is dark. On the other hand, when propagating in the TE2 mode within the core region 112 like the first light 202, it exhibits a ``doughnut-shaped intensity distribution in which the center is relatively dark and the areas slightly shifted from the center are bright.'' . Therefore, by observing the intensity distribution of the light emitted from the optical fiber, it is possible to predict the difference in the mode of the light propagating within the core region 112.

The value of κ in Equation 31 is determined from the experimental results shown in FIG. 17A. The appropriate value of κ is considered to be 3/4 (preferably 1/2). Furthermore, when κ is set to 1/4, the probability of taking the TE2 mode increases.

FIG. 15C(c) shows that the incident angle θ of the third light 206 (the angle between the traveling direction of the third light 206 immediately before entering the entrance surface 92 of the predetermined optical member and the perpendicular line 96 on the entrance surface side) is The state is shown when the light is set to be even larger than the light 202. The condition for the incident angle θ at this time is

で与えられる。図１５Ｃ（ｃ）右図は、ＴＥ３モードの電場分布１５２を示す。この場合には、コア領域１１２の中心部で電場の値が負値を取る。そしてＴＥ３モード（高次モード）が取れるコア領域１１２内直径Ｄの条件は、数式２８で与えられる。

is given by The right diagram in FIG. 15C(c) shows the electric field distribution 152 in the TE3 mode. In this case, the value of the electric field takes a negative value at the center of the core region 112. The condition for the inner diameter D of the core region 112 that allows the TE3 mode (higher order mode) is given by Equation 28.

When the focused light using the condensing lens 330 enters the core region 112, the incident angle θ changes at the passing position of the condensing lens. Therefore, light propagates within the core region 112 in a state in which different mode-forming lights are mixed.

FIG. 16A shows a combination of mode-forming light that is bilaterally symmetrical and mode-forming light that is asymmetrical with respect to the center position within the core region 112. FIG. 16A(a) shows an electric field distribution 152 of light forming a bilaterally symmetrical fundamental mode (TE1 mode). Further, FIG. 16A(b) shows an electric field distribution 152 of left-right asymmetric TE2 mode forming light. FIG. 16A(c) shows an electric field distribution 152 that combines both.

In the TE2 mode shown in FIG. 16A(b), there are two cases in which the position 124 exhibiting a large electric field value is on the left side (L) and on the right side (R). Therefore, the center of gravity position when taking the intensity distribution of the combined light (FIG. 16A(c)) is shifted between the left diagram (L) and the right diagram (R). That is, on the left side (L) of FIG. 16A(c), the center of gravity position 116A is shifted to the left side from the center position within the core region 112. Further, on the right side (R) of FIG. 16A(c), the center of gravity position 116B is shifted to the right side from the center position within the core region 112. This gravity center position shift is not limited to light forming the TE2 mode. For example, when arbitrary lights such as TE4 and TE6 whose electric field distribution 152 exhibits a left-right asymmetrical characteristic are combined, a shift in the center of gravity occurs. The explanation so far has mainly focused on SI type optical fibers. However, the above description is not limited to this, and the above description is also applicable to GI type optical fibers.

FIG. 16B shows an embodiment in which speckle noise is reduced by utilizing this center of gravity position shift. A mask pattern MP is placed in the optical path of the parallel light to extract only the upper fan-shaped area A within the laser beam cross section 510. The condenser lens 330 condenses this extracted light into the core region 112 of the waveguide element (optical fiber/optical waveguide/light guide) 110. Then, at the exit of this waveguide element (optical fiber/optical waveguide/light guide) 110, a gravity center position 116A of the intensity distribution occurs at a position shifted from the center position of the core region 112. A collimating lens 318 converts the light emitted from the waveguide element (optical fiber/optical waveguide/light guide) 110 into parallel light.

When only the lower fan-shaped region B in the laser beam cross section 510 is extracted, a center of gravity position 116B of the intensity distribution occurs within the exit plane of the waveguide element (optical fiber/optical waveguide/light guide) 110. This center of gravity position 116B appears at a position opposite to the center of gravity position 116A based on the center position of the core region 112.

The traveling directions of the parallel light after passing through the collimating lens 318 are slightly shifted from each other in A and B. Consider a case where a relationship (phase asynchronization 402) in which light A extracted in the upper fan-shaped region A and light B extracted in the lower fan-shaped region B do not interfere is established. When the measurement object 22 is simultaneously irradiated with the lights A and B, which travel in different directions using the Keller illumination system, speckle noise is reduced as described with reference to FIG. 13.

FIG. 16C shows an example embodiment that uses optical property conversion elements to reduce speckle noise. The laser beam cross section 510 is divided into eight regions (angular division) in the angular direction around the optical axis. The light (elements) that have passed through each region have an optical path length difference that is greater than or equal to (twice the value of) the coherence length ΔL ₀ . Then, within the exit plane of the waveguide element (optical fiber/optical waveguide/light guide) 110, eight barycenter positions 116 with mutually different intensity distributions are formed.

If the laser beam cross section 510 is divided into angles, asymmetric electric field modes (TE2, etc.) are likely to be formed within the core region 112. This produces the effect of improving the speckle noise reduction effect.

In FIG. 16C or 16B, a focusing lens 330 focuses light onto the entrance surface 92 within the core region 112. Experiments have confirmed that when the spot size incident on the incident surface 92 in the core region 112 is increased by shifting the light collection position, the speckle noise reduction effect weakens. When the spot size on the entrance surface 92 in the core region 112 is increased, the frequency of total reflection at the interface between the core region 112 and the cladding region 114 increases. Since a phase shift occurs due to total reflection at this interface, the effect of reducing speckle noise is weakened.

In order to ensure a large speckle noise reduction effect, the ratio of the spot size (diameter) to the inner diameter D of the core region 112 must be 1 or less. Moreover, this ratio is desirably 3/4 or less, or 1/2 or less.

The spot size here is defined as the effective beam diameter of the optical system. For example, the effective beam diameter may be defined as the diameter when the maximum diameter of the laser beam cross section 510 that can pass through the condenser lens 330 is projected onto the incident surface 92 in the core region 112. The light intensity on the light collecting surface does not have a rectangular characteristic, but often takes a light intensity distribution that is maximum at the center and decreases at the periphery. Taking this situation into account, the diameter of the range that takes half the maximum intensity in the intensity distribution on the incident surface 92 in the core region 112 (half-width) or the diameter of the range that takes the e ^-2 value of the maximum intensity (e ^{- 2} width) may be regarded as the spot size.

Furthermore, if the center of the spot (laser beam cross section 510) on the incident surface 92 in the core region 112 deviates significantly from the center of the core region 112, the phase shift due to total reflection at the interface between the core region 112 and the cladding region 114 will occur. The amount of shift increases. Therefore, the allowable amount of deviation between the center of the spot (laser beam cross section 510) on the incident surface 92 in the core region 112 and the center of the core region 112 in order to obtain the effect of reducing speckle noise will be explained. With respect to the inner diameter D of the core region 112, this amount of deviation needs to be D/2 or less. Further, this amount of deviation is preferably D/4 (or D/8) or less.

The TE3 mode light propagating within the core region 112 has electric field distribution characteristics that are symmetrical with respect to the center position of the core region 112. Therefore, the TE3 mode light does not contribute to an increase in the amount of deviation of the center of gravity of the intensity distribution. Therefore, in order to effectively reduce speckle noise, it is desirable to satisfy the condition of sin θ≦κNA for all incident angles θ of light incident on the core region 112.

In addition, the amount of deviation of the center of gravity in the intensity distribution of the combined light (FIG. 16A(c)) is the total amplitude between the second light 204 forming the reference mode (TE1 mode) and the first light 202 forming the TE2 mode. It changes depending on the amount. That is, when the relative total amplitude amount of the first light 202 forming the TE2 mode is increased, the amount of gravity center position shift in the intensity distribution of the combined light increases. Conversely, if the first light 202 forming the TE2 mode does not exist, no shift in the center of gravity within the intensity distribution of the combined light occurs. Therefore, in order to effectively reduce speckle noise, the maximum incident angle θ for all light incident on the core region 112 needs to satisfy Expression 31.

In this embodiment, a difference in the incident angle (difference in traveling direction) between the first light 202 and the second light is used to generate a difference in mode within the core region 112. Therefore, this embodiment assumes the use of a multimode fiber (either SI type or GI type may be used). Therefore, it is necessary to satisfy Equation 28 regarding the diameter D within the core region.

Section 5.4 Optical Noise Reduction Effect FIG. 17A shows the experimental results that confirmed the speckle noise reduction effect in this embodiment. The 520 nm wavelength light emitted from the semiconductor laser element 500 was passed through the optical system shown in FIG. 16C. The light after passing through the collimating lens 318 was reflected in a 90 degree direction on the surface of the diffuser plate with an average surface roughness Ra of 2.82 μm. This reflected light was then observed with a CCD camera. The multimode optical fiber used in the experiment was an SI type with a core diameter D of 600 μm, an NA value of 0.22, and a total length of 1.5 m.

The standard deviation of the distribution characteristic obtained by dividing the fluctuation value of the measured light intensity caused by speckle noise by the average value is defined as speckle contrast Cs (speckle contrast), and the Cs value when using conventional light is shown on the left side of Figure 17A. Shown on the vertical axis. The right vertical axis of FIG. 17A shows the ratio of the Cs value when using the optical characteristic conversion element 210, which is angularly divided into eight regions, to the Cs value when using conventional light.

The ratio of the NA value to the sine function value sin θ of the maximum incident angle θ for all the light incident on the core region 112 calculated using the effective beam system is set on the horizontal axis of FIG. 17A. As the value on this horizontal axis increases, the spec noise reduction effect increases.

FIG. 17B shows the change in the Cs value when the angular division (horizontal axis) of the optical property conversion element 210 is changed. The experimental conditions are the same as in FIG. 17A. When the angle division is 1, a conventional optical system is shown before using the optical characteristic conversion element 210. As the number of angular divisions increases, the amount of speckle noise decreases.

The sine function value of the maximum incident angle θ for all the lights incident on the core region 112 calculated using the effective beam system is defined as the execution NA value. FIG. 17B(a) shows the experimental results when the execution NA value is 1/29, and FIG. 17B(b) shows the experimental result when it is 1/44. Here, an optical fiber with an NA value of 0.22 was used in the experiment. Therefore, the converted value in FIG. 17B(a) is NA/sinθ=29×0.22=6.4, and the converted value in FIG. 17B(b) is NA/sinθ=44×0.22=9.7 becomes.

Chapter 6 Light source unit capable of emitting arbitrary waveform light in time series direction
Section 6.1 Arrangement of Optical System Having a Function of High-speed Control of Light Emission Amount FIG. 18A shows an example of an embodiment regarding an optical system in the light source unit 2 that can support a function of high-speed control of the light emission amount. A cross section 510 of emitted light from the semiconductor laser device 500 has elliptical characteristics. In order to correct the elliptic characteristic, two cylindrical lenses 256 and 258 whose bus bars are perpendicular to each other are used. That is, the long-axis side cylindrical lens 256 converts the emitted light from the semiconductor laser element 500 into parallel light in the long-axis direction. The short-axis side corresponding cylindrical lens 256 converts the emitted light from the semiconductor laser element 500 into parallel light in the short-axis direction.

At a location where the laser beam cross section 510 becomes approximately circular, an optical characteristic changing element 210 that divides the angle into eight regions is placed. As shown in FIG. 17B, increasing the number of angular divisions in the optical characteristic conversion element 210 increases the speckle noise reduction effect. Therefore, the number of angular divisions may be set to an arbitrary number.

The optical path converting prism 252 splits the light passing through the optical characteristic changing element 210 into a photodetecting element 250 and a waveguide element (optical fiber/optical waveguide/light guide) 110. The light input/output surface within the optical path converting prism 252 is an antireflection coated surface 246 . Further, on the total reflection surface 248, the light is totally reflected within the optical path changing prism 252.

The condensing lens 330-1 condenses a portion of the light reflected by the reflecting surface 254 on the light receiving surface of the photodetector element 250. Further, the condenser lens 330-2 condenses the remaining light toward the waveguide element (optical fiber/optical waveguide/light guide) 110.

Section 6.2 Example of Internal Structure of Light Source Section FIG. 18B is a diagram illustrating detailed contents of a part of FIG. 1. In FIG. 18B, only the photodetector element 250 and the semiconductor laser element 500 in the light source section 2 shown in FIG. 18A are extracted and illustrated.

The inside of the light emission amount control section 30 is composed of a preamplifier circuit 716, a differential calculation circuit 712, and a current drive circuit 718. The light emission amount signal detected by the photodetector element 250 is amplified by the preamplifier circuit 716. The difference calculation circuit 712 calculates the difference value between the light emission amount signal amplified by the preamplifier circuit 716 and the signal given from the time-varying light emission amount generation circuit 728, and outputs this difference value to the current drive circuit 718. The current drive circuit 718 controls the amount of light emitted from the semiconductor laser device 500 by driving the semiconductor laser device 500 with a current value corresponding to this output signal.

The recording signal generation section 32 includes a time-varying light emission amount generation circuit 728 and a memory circuit 726. This recording signal generation section 32 can generate any complex time-varying light emission pattern. This allows light emission based on a complex and arbitrary time-varying light emission pattern. A memory circuit 726 stores this complex and arbitrary time-varying light emission pattern. Information on this complex and arbitrary time-varying light emission pattern may be recorded in advance in an external storage medium such as a USB memory or a hard disk. In this case, time-varying light emission pattern information is transferred into the memory circuit 726 via the external storage element drive circuit 72 under the control of the control circuit 720 .

For example, when the light source section 2 and the measurement section 8 are to perform complex time-series processing that will be described later in Chapter 8, highly accurate synchronization between the light source section 2 and the measurement section 8 is required. A connection terminal for synchronization is provided. A signal line 730 for synchronization with the outside (including the measurement unit 8) is installed at this connection terminal for synchronization, and a reference clock synchronized with the signal transmitted through the signal line 730 for synchronization with the outside is provided. It is generated within the reference clock generation circuit 732.

A communication control unit 740 is installed in order to perform time-series highly accurate cooperative operations with the outside including the measurement unit 8. Note that this communication control unit 740 is included in a part of the information transmission path 4 described in FIG. The light source section 2 described here has a structure that allows information communication via either wired or wireless communication media. Then, the wired communication execution unit 738 controls information communication by wire with the outside. Further, a wireless communication execution unit 736 controls wireless information communication with the outside. The communication control interface processing unit 742 performs information processing (data processing) regarding the information content communicated via either wired or wireless route.

For example, information communicated with the outside including the measurement unit 8 may have a complicated data structure as described later with reference to FIG. 19C. The communication information decoding unit 748 decodes such a complicated data structure. Furthermore, the light emission pattern of the semiconductor laser element 500 may include confidentiality, and encrypted information may be transferred. The authentication processing control unit 746 performs processing related to the transfer of encrypted information, such as authentication processing with a communication partner and encryption key exchange.

In the description of the electronic circuit shown in FIG. 18B, the electronic circuit was explained as an example applied to the optical system described in FIG. 18A. However, the present invention is not limited thereto, and may be applied to, for example, the optical system shown in FIG. 9I. In this case, all operations can be performed simply by replacing the semiconductor laser element 500 in FIG. 18B with the light emitting section 470. Furthermore, as another embodiment, the electronic circuit shown in FIG. 18B may be applied to any light source section 2. When the embodiment described in FIG. 18B is combined, the amount of light emitted can be controlled with high precision by distributing a part of the emitted light from the light source section 2 to the photodetecting element 250 and monitoring the amount of light emitted.

Section 6.3 Format example of light emission waveform setting The method for setting a complex and arbitrary time-varying light emission pattern generated in the recording signal generation unit 32 is basically a digital signal of a ``series of light emission amounts at predetermined time intervals.'' stipulated. The amount of light emitted at each elapsed time is expressed in binary data. Therefore, as this time-varying light emission pattern, a CSV file format or a relational database format representing a binary data series for each elapsed time may be adopted.

FIG. 19A shows an example embodiment of a data format that defines a light emission waveform. Here, a plurality of different light emission patterns can be defined simultaneously. A time-varying light emitting pattern ID (identification) (identification information) 750 is set at the beginning so that each time-varying light emitting pattern can be identified. Placing the time-varying light emitting pattern ID (identification information) 750 at the beginning or a location near the beginning has the effect of facilitating the light emitting pattern search.

The reference clock frequency 752 method defines the reference clock frequency generated by the reference clock generation circuit 732. The data step time interval 754 indicates the time interval when setting the amount of light emission for each elapsed time. The time-varying light emitting pattern duration 756 represents the duration of the light emitting pattern defined by the time-varying light emitting pattern ID (identification information) 750. By using the information on the time-varying light emitting pattern duration 756, the duration of the light emitting pattern can be known in advance. As a result, there is an effect that the convenience of advance preparation for light emission control is improved.

The total number of steps 758 of the time-varying light emitting pattern represents the number of steps of the time-series changing light emitting pattern defined by the time-varying light emitting pattern ID (identification information) 750. The value obtained by multiplying the total number of steps 758 of this time-varying light emitting pattern by the data step time interval 754 corresponds to the time-varying light emitting pattern duration 756.

The dynamic range (bit gradation number) 760 of the time-varying light emission amount represents the number of representation bits of binary data that defines one light emission amount. By increasing the number of bits, it is possible to set even minute changes in the amount of light emitted. The full range output light amount value 762 indicates the light amount value output from the light source section 2 when the binary data is set to the maximum value.

Identification of the time-varying light emitting pattern specified from the outside is basically specified using information of the time-varying light emitting pattern ID (identification information) 750. In this embodiment, as an alternative method, a time-varying light emission pattern can be specified using an analog signal level input from the outside. For example, a signal line for external synchronization can be set to an analog level, and the signal level set by this signal line can be used to switch the time-varying light emission pattern. The information used at this time corresponds to an input signal level maximum value 764 that specifies the light emission pattern ID and an input signal level minimum value 766 that specifies the light emission pattern ID. For example, when the analog signal level input from the outside is set to a level that is less than the maximum input signal level value 764 that specifies the emission pattern ID and equal to or higher than the minimum input signal level value 766 that specifies the emission pattern ID, A variable luminescence pattern may be emitted.

In this embodiment, when the light emission level is set to "0", the light source section 2 is basically in a state of "no light emission". However, the present invention is not limited to this, and even when the light emission level is set to "0", a slight amount of light may be emitted. The small amount of light emitted at this time can be set as the idling light amount value 770. If the idling light emitting amount value 770 is other than "0", the value of the idling light emitting amount presence/absence flag 768 becomes "1".
In the binary data series indicating the amount of light emitted at each elapsed time for each time-varying light emission pattern ID (identification information) 750, binary values are arranged below the above data according to the elapsed time. The value of the total data size 772 at this time is given by the product of the value set in the total step number 758 of the time-varying light emitting pattern and the value set in the dynamic range (number of bit gradations) 760 of the time-varying light emitting amount. .

Section 6.4 Light emission communication control example
FIG. 19B shows an example of communication control between the inside of the light source section 2 and the outside thereof. Here, the external part of the light source unit 2 that is the communication partner is called a host. In the embodiment of FIG. 1, this host may be associated with the internal system control unit 50.

Here, an example is shown in which a light emission pattern is transmitted 788 from the host 50 side to the light source section 2 in advance, and then the light emission timing is synchronized between the host 50 and the light source section 2. After synchronizing the light emission timing, the light source section 2 starts emitting light in the specified light emission pattern.

In any case of communication, there is a mutual authentication period 780 first. First, a host ID is transmitted from the host 50 side to the light source unit 2. When the light source section 2 receives the host ID, the light source section 2 returns the light source section ID to the host side. Next, the host 50 transmits the host side encryption key to the light source section 2, and then the light source section 2 transmits the light source section side encryption key to the host 50 side. Providing such a mutual authentication period 780 has the effect that the light source unit 2 can communicate information with any device around the world via the Internet.

In the next control signal communication period 790, a control signal is encrypted with a special key (for example, a composite key of a host side encryption key and a light source side encryption key) generated from the encryption key exchanged between the host 50 and the light source unit 2. Information is communicated.

In the light emission pattern transmission period 788, information on the light emission pattern is transmitted 784 after the control signal transmission period 790. Here, during the pattern transmission period 784 as well, the light emission pattern information is encrypted with a special key (for example, a composite key of the host side encryption key and the light source side encryption key) generated from the encryption key exchanged between the host 50 and the light source unit 2. is transmitted in the format shown in FIG. 19A.

On the other hand, during the period of light emission timing synchronization 798, a light emission period 794 begins after the control signal transmission period 790, and light emission in a specified pattern is started.

FIG. 19C shows an example data structure within a control signal 790 sent during a light emission timing synchronization period 798. The control signal 790 in FIG. 19C(a) has a data structure shown in FIG. 19C(b). The first placed preamble 640 is used for synchronization. The structure of the source/receiver confirmation information 620 placed next (transmitted after the preamble 640) is shown in FIG. 19C(c). First, an ID (identification information) 622 on the host (sending source) side is transmitted, followed by an ID (identification information) 628 on the light source (receiving destination) side. As the information transmitted here, an IP address may be used in addition to the ID (identification information).

The control signal identification information 642 stores type information of the control signal 790 transmitted this time. Using this type information, it is possible to identify whether it is the light emission pattern transmission period 788 or the light emission timing synchronization period 798.

In the area of the light emitting pattern identification information 750, any information of the identification information registered in the time-varying light emitting pattern ID (identification information) of FIG. 19A can be written. The light source section 2 decodes the information stored in this light emission pattern identification information 750 and recognizes the light emission pattern that emits light immediately after this.

The light emission start timing designation information 648 specifies the timing at which the light source section 2 starts emitting light. Specifically, the start timing of the synchronization preamble 640 or the transmission start (or reception start) timing of this light emission start time designation information 648 is set as a reference timing, and the delay time from this reference timing to the start of light emission is specified. For example, when performing complex time-series processing in which the light source section 2 and the measurement section 8 cooperate, which will be described later in Chapter 8, the light source section 2 and the measurement section 8 may ) requires highly accurate timing synchronization. By using this light emission start timing designation information 648, an effect is produced in which highly accurate synchronization processing between the light source section 2 and the measuring section 8 can be performed.

In the content explained at the beginning using FIG. 1, the single optical element position 10 incorporates the light source section 2 explained in Chapter 6 of this book. However, the present invention is not limited thereto, and the light source unit 2 described in Chapter 6 of this book may exist independently and be connected to the host 50 via the Internet. When used as part of an arbitrary system within the Internet, rather than as a stand alone type, the light source unit 2 has the effect of greatly expanding its applications.

Chapter 7 Combination of Optical Noise Reduction and Electrical Noise Reduction Section 7.1 High-precision measurement method in optical application field FIG. 20A shows a high-precision measurement method in this embodiment. In FIG. 20A, the main parts inside the optical device 10 described in FIG. 1 are extracted and drawn. That is, optical measurement 1002 is performed on the measurement object 24 within the measurement unit 8 . The signal processing unit 42 then analyzes the results of the optical measurement 1002 and extracts necessary information 1004.

Here, in order to perform highly accurate information extraction 1004, it is necessary to reduce disturbance noise to a minimum in both the optical measurement 1002 and information extraction 1004 processes. Two types of disturbance noise, optical noise and electrical noise, are likely to be mixed here. Therefore, in order to perform high-precision measurement, two types of disturbance noise reduction are desirable: optical disturbance noise reduction and electrical disturbance noise reduction 1012.

By using the methods already described in Chapters 2, 3, and 5, it is possible to significantly reduce optical noise. In the prior art, this optical noise reduction technology was not available, so there was a problem in that it was difficult to fully demonstrate the effect of electrical disturbance noise reduction processing. Highly accurate information extraction 1004 is possible based on the combination 1012 of the optical noise reduction method already explained in Chapters 2, 3, and 5 and the existing electrical disturbance noise reduction method.

As a specific method for the combination 1012 of the optical noise reduction method and the electrical disturbance noise reduction method, processing 1000 may be performed using the following procedure. This processing procedure 1000 is
1. Acquisition of first information using detection light from measurement target object 222. 3. Perform processing for optical disturbance noise reduction or electrical disturbance noise reduction 1012 in the detection signal using the first information. Second information acquisition processing is sequentially performed using the noise-reduced signal after the above processing.

The extracted information extracted 1004 with high accuracy obtained here is transferred 1006 via the information transmission path 4. As an example of the transfer format 1014 used during this information transfer 1006,
A] Diversion of existing image and video compression methods or their expanded formats B] Multiplex transfer method of packs or packets distributed for each type of data C] Relationships linked (managed) within hypertext Individual transfer of each file may also be used.

Various information transferred 1006 in this transfer format 1014 is saved 1010 in the collected information storage area 74. Alternatively, it may be displayed 1008 on the display unit 18 or the information providing unit 72.

FIG. 20B shows a list of examples of information used in this embodiment. The information can be classified into categories 1020 such as unnecessary optical effects, the shape and position of the object to be measured, detection of a moving object to be measured, the composition ratio of the constituent parts, and activities that change over time.

In addition, the extracted information summary 1022 includes optical effects inside the measurement target, optical effects on the surface of the measurement target, optical effects in the middle of the light propagation path, shape contour information and feature information, and moving body area. Examples include analysis of constituent materials in solids, content of substances in liquids, and biological activities.

FIG. 20C shows a list of disturbance noise generation causes 1036 and countermeasures 1038 for each measurement target region 1032 within the measurement target object 22. The causes of electrical disturbance noise 1036 are shot noise, thermal noise, electromagnetic induction noise, etc., regardless of the measurement target area 1032.

As the electrical disturbance noise reduction method 1038 in this embodiment, only the carrier component may be extracted E1 by band-limiting the detection signal. Furthermore, the present embodiment is not limited to this, and lock-in amplification (Lock-in Amplifier) E2 may be performed. This lock-in amplification E2 requires synchronization of the frequency and phase of the reference signal with respect to the detection signal. Therefore, in this embodiment, various information included in the category 1020 of activities with time changes in FIG. 20B may be used as the first extracted information 1004 to perform the frequency and phase synchronization.

In addition to the method 1038 for reducing electrical disturbance noise, the error correction function E3 of the digitized signal may be used. As a specific example, a technique such as PRML (Partial Response Most Likelihood) may be used to automatically correct the signal sequence to the most appropriate signal sequence.

The cause 1036 of optical disturbance noise differs slightly depending on the measurement target area 1032 within the measurement target object 22. A common cause 1036 of optical disturbance noise in both cases is the influence of optical interference noise. This method of reducing optical interference noise corresponds to the technical content already explained in Chapters 2, 3, and 5.

Other causes of optical disturbance noise 1036 include the contamination of other optical effects. In this embodiment, the signal processing unit 42 performs arithmetic processing (signal processing or signal analysis) L3 between measurement signals to prevent the influence of other optical effects from being mixed in. remove.

The relationship between the processing procedure in this case and the processing procedure 1000 leading to the second information extraction already described with reference to FIG. 20A will be described.
1. In the processing procedure corresponding to the acquisition of the first information using the detection light from the measurement object 22, the signal processing section 42 detects other optical effects from the measurement signal acquired from the measurement section 8 or the signal reception section 40. The process of extracting 1004 information based on the result corresponds to first extracted information 1004. Next 2. Performing the process of optical disturbance noise reduction or electrical disturbance noise reduction 1012 in the detection signal using the first information,
This corresponds to the process of removing the component of the first extraction information 1004 from the measurement signal. And 3. The acquisition of the second information is
This corresponds to a second information extraction after the influence of other optical effects has been removed.

The cause 1036 of optical disturbance noise that occurs depending on the measurement target area 1032 within the measurement target 22 is that it does not occur when measuring the comprehensive characteristics of the entire measurement target 22, but only local characteristics within the measurement target 22. There is a cause 1036 that occurs for the first time when measuring. The optical disturbance noise generation cause 1030 is the influence of disturbance light entering from outside the local region to be measured.

In this embodiment, as a method 1038 for reducing the influence of disturbance light entering from outside the local area to be measured, an aperture is provided at an imaging position or a confocal position for the local area to be measured. A limit may be set to block unnecessary disturbance light L4. Accordingly, when performing three-dimensional measurement inside the measurement target object 22, for example, it is possible to prevent detection light from a depth position other than the local area to be measured from being erroneously measured as disturbance light.

Section 7.2 Various Embodiments Applying Lock-in Amplification Technology FIG. 21A shows an example of this embodiment. In the embodiment shown in FIG. 21A, first extraction information 1218 is extracted from the measurement signal obtained from the measurement unit 8 (or signal reception unit 40). A time-series spectral characteristic signal, a time-series image signal, or a data cube signal obtained from the measuring section 8 in the optical device 10 is transferred to the signal receiving section 40 . As information extraction 1004 within the signal receiving unit 40, a predetermined time series signal 1208 is partially extracted 1202 from this input signal.

A predetermined time-series signal 1208 partially extracted 1202 within the signal receiving unit 40 is transferred to the signal processing unit 42. The signal processing unit 42 performs reference signal extraction 1210 using the predetermined time series signal 1208. Then, the DC component is further removed 1212 from this reference signal, and the form containing only the AC component is used as first extracted information 1218.

At the same time, the time-series spectral characteristic signal, time-series image signal, or data cube signal transferred from the signal receiving unit 40 to the signal processing unit 42 is multiplied 1230 by the first extraction information 1218 described above. If the signal transferred to the signal processing unit 42 is a time-series spectral characteristic signal, multiplication is performed for each measurement wavelength. Further, if the signal transferred to the signal processing unit 42 is a time-series image signal, multiplication is performed for each pixel. Furthermore, when the data cube signal is transferred, multiplication is performed for each measurement wavelength within each pixel.

As a result of this multiplication, time-series DC components are extracted 1236 for each wavelength or each pixel by the action of an ultra-narrow band low-pass filter, and second extraction information 1018 is generated in the predetermined signal extraction section 680. . As another method for processing the result of this multiplication, band limitation may be performed to extract only the carrier component corresponding to the first extraction information 1218 E1. However, rather than carrier component extraction E1 based on band limitation, extracting only the DC component by lock-in amplification E2 has a higher DC component extraction effect and improves the accuracy of the second extraction information 1018.

FIG. 21B shows another embodiment of this embodiment capable of reducing electrical disturbance noise. In FIG. 21A, first extracted information 1218 is extracted 1004 from the measurement signal from the measurement unit 8. In contrast, in another embodiment shown in FIG. 21B, first extraction information 1218 is extracted 1004 from a predetermined time-series signal 1208 obtained from the light emission amount control unit 30. As the predetermined time series signal 1208 obtained from the light emission amount control section 30, for example, an output signal from the light emission amount output circuit 702 in FIG. 18B may be used.

For example, when measuring in an environment where ambient light is likely to enter, the measurement accuracy will be significantly reduced due to the influence of the ambient light. In this case, the amount of predetermined light 230 emitted from the light emitting unit 2 is modulated, and only the signal component corresponding to the modulated light is extracted 1004 as second extraction information 1018 as shown in FIG. 21B. is significantly improved.

FIG. 21C shows a method of reducing electrical disturbance noise by irradiating the measurement object 22 with pulsed light as an example of an applied embodiment of FIG. 21B. Here, the light emission amount modulation signal 1228 transmitted from the signal processing section 42 to the light emission amount control section 30 may take the form of a rectangular pulse waveform.

In the example application embodiment of FIG. 21C, the reference pulse is generated 1220 in the time-varying component extraction processing section 700 within the data processing block 630. In the pulse counter 1222, a pulse is generated once every predetermined number of times the reference pulse 1220 is generated. The pulses output by this pulse counter 1222 are used as the first extraction information 1218. This first extraction information 1218 is used as a light emission amount modulation signal 1228 in the light emission amount control unit 1228, and the amount of light irradiated onto the measurement object 22 changes in a rectangular pulse shape in accordance with this light emission amount modulation signal 1228. . This first extraction information 1218 (output pulses of the pulse counter 1222) is also simultaneously transferred to the multiplication circuit 1230 for each wavelength or each pixel. In this way, in the example application embodiment shown in FIG. 21C, the same first extracted information 1218 is used for multiple purposes simultaneously.

The time-series spectral characteristic signal, time-series pixel signal, or data cube signal obtained from the measurement unit 8 is detected in synchronization 1224 with the reference pulse 1220 generated in the time-varying component extraction processing unit 700, and the time-varying component is detected. The signal is transferred to a multiplication circuit 1230 for each wavelength or each pixel in the extraction processing section 700.

When the first extracted information 1218 has a pulsed rectangular waveform as shown in FIG. 21C, the multiplication circuit 1230 for each wavelength or each pixel can be configured with a very simple circuit. The multiplication circuit 1230 for each wavelength or pixel is composed of only an inverter (polarity inversion) circuit 1226 and a switch 1232. Then, in accordance with the first extraction information 1218 given from the pulse counter 1222, the polarity of the signal transmitted to the time-series DC component extraction circuit (ultra-narrow band low-pass filter) 1236 for each wavelength or pixel is switched (the first The signal polarity switching in synchronization with the extraction information 1218 will be described later).

Note that the applied embodiment example shown in FIG. 21C may be used for length measurement or three-dimensional image measurement (three-dimensional image measurement). Light propagates through air at a speed of approximately 3×10 8 m/s, so in a pulse width period of 1 nS, light travels approximately 30 cm. The distance to the measurement object 22 can be measured (length measurement) by measuring the time it takes for the light reflected from the surface of the measurement object 22 placed far away to return. For example, if a pulse with a pulse width of 1 nS and a duty ratio of 50% is used as the reference pulse 1220 and a change in reflected light intensity is measured according to the pulse count value 1222, length can be measured with a spatial distance resolution of 30 cm. Furthermore, when the reflected light from the measurement object 22 is measured as an image signal by the image sensor 300, three-dimensional image measurement (three-dimensional image measurement) becomes possible.

Specifically, the above reference pulse 1220 is fixed, and the pulsed light emission amount (light emission amount modulation signal) 1223 from the light emission amount control section 30 is controlled at intermittent timing according to the pulse count value 1222. At the same time, the output signal 1200 for each pixel from the image sensor 300 is transmitted to the time-varying component extraction processing section 700 in synchronization with the reference pulse 1220 described above.

The length measurement method itself using laser pulses is applied to LiDAR (Light Detection and Ranging) used for self-driving cars. However, when conventional techniques are used for image measurement, the measurement accuracy is significantly reduced due to speckle noise caused by the coherence of laser light. However, by using the spatial interference noise reduction method explained in Chapter 12, highly accurate length measurement and three-dimensional image (video) measurement becomes possible.

Section 7.3 Structure of charge storage type signal receiver
FIG. 22 is a characteristic explanatory diagram when a charge accumulation type signal receiving section is used as the measuring section 4. Most of the spectral characteristic signals, image signals, and data cube signals cannot be obtained continuously in time series, but are time-divided into a measurement period 1258 and a data transfer period 1254 (Fig. 23A (a) and Fig. 23B ( a)). That is, during the measurement period 1258, measurement data is accumulated in the charge amount storage section 1170. Then, during the data transfer period 1254, the accumulated data is transferred to the signal processing section 42 via the data transfer section 1180.

FIG. 22 shows an example of the principle of generating a spectral characteristic signal using an organic semiconductor. Each of the organic semiconductor layers 1102, 1104, and 1106 has a different absorption wavelength for the detection light 1100. In other words, the first organic semiconductor layer 1102 closest to the incident side of the detection light 1100 absorbs only the detection light 1100 in a predetermined wavelength range. Then, only the detection light 1100 containing light of other wavelengths that has escaped absorption by the first organic semiconductor layer 1102 passes through the first organic semiconductor layer 1102. The second organic semiconductor layer 1104 absorbs the detection light 1100 in other wavelength ranges among the other wavelengths of light that have escaped absorption in the first organic semiconductor layer 1102.

Furthermore, the organic semiconductor layers 1102, 1104, and 1106 are each sandwiched between a pair of transparent conductive films, and the transparent conductive films are further partitioned by transparent insulating layers 1124 and 1126. Further, pixel regions 1152 and 1154 are defined by the arrangement of the transparent conductive films. That is, the left side in the left diagram of FIG. 22 forms the first pixel area 1152, and the right side forms the second pixel area 1154.

When the detection light 1100 in a predetermined wavelength range is absorbed within the organic semiconductor layers 1102, 1104, 1106, charges are generated within the organic semiconductor layers 1102, 1104, 1106, and are used as detection signals. For example, when the detection light 1100 enters the left side of the first organic semiconductor layer 1102 and is absorbed within the first organic semiconductor layer 1102, charges are generated within the first organic semiconductor layer 1102. Since the lower transparent conductive film 1112 adjacent to the first organic semiconductor layer 1102 is connected to the ground line, the charges generated within the first organic semiconductor layer 1102 are preamplified via the transparent conductive film 1142. Enter 1150-6.

The charge that has entered the preamplifier 1150-6 is stored in the capacitor 1160-6 for a predetermined period (during the measurement period 1258). As described above, a feature of the charge accumulation type signal receiving section 40 is that charge is continuously accumulated in the capacitor 1160-6 within a predetermined period (during the measurement period 1258). The amount of charge stored in this capacitor 1160-6 is transferred to the amount of charge storage section 1170-2 at the end of a predetermined period, and then the amount of charge is discharged. Thereafter, charge is again stored in the capacitor 1160-6 during the next predetermined period (during the measurement period 1258).

For example, when the detection light is separated for each measurement wavelength using the spectroscopic element (blazed grating) 320 in FIG. 12A or FIG. 12B21A, a line sensor or a two-dimensional array sensor is used as the image sensor 300. In this case as well, similarly to FIG. 22, the measurement signal is output in a time-divided manner into the measurement period 1258 and the data transfer period 1254.

Therefore, in this embodiment, the detection signal band limiting method E1 or lock-in amplification method E2, which is suitable for a measurement signal in which the measurement period 1258 and the data transfer period 1254 are time-divided, and the error correction method E3 of the digitized signal are used. (See column 290 in FIG. 20C). In particular, when measurement is performed using weak detection light, the measurement period 1258 becomes relatively long, and measurement accuracy using the band limit E1 and lock-in amplification E2 tends to deteriorate. In particular, when the first extraction information 1218 is extracted 1004 from the time-series spectral characteristic signals, time-series image signals, and data cube signals obtained from the measurement unit 8 as illustrated in FIG. 21A, the measurement period 1258 is When the time length becomes longer, the extraction accuracy of the first extraction information 1218 tends to decrease.

Section 7.4 Example of Signal Processing Form of Charge Accumulation Signal FIG. 23A shows a method of extracting first extraction information 1218 with high precision 1004 for a relatively long measurement period 1258. Here, the lock-in amplifier circuit E2 described in FIG. 21A is used.

Blood vessels run within the bodies of higher organisms. The blood vessels expand and contract repeatedly in accordance with the pulsations (changes in blood flow 1252). When near-infrared light is irradiated around this blood vessel, the amount of near-infrared light absorbed changes over time in synchronization with the expansion and contraction of the blood vessel. FIG. 23A shows a processing method up to information extraction 1004 in which changes in near-infrared light absorption amount in response to changes in blood flow 1252 are used as first extraction information 1218.

As shown in FIG. 23A(a), a measurement signal obtained by time-sharing a measurement period 1258 and a data transfer period 1254 enters the signal processing unit 42. FIG. 23A(b) shows an example of a time-divided measurement signal format sent from the signal receiving section 40. Further, in FIG. 23A(b), the vertical axis represents the blood flow rate 1252 obtained as a change in the absorption amount of near-infrared light. Further, the horizontal axis in FIG. 23 indicates elapsed time 1250.
As shown in FIG. 23A(b), no measurement signal is obtained from the charge storage type signal receiving section (measuring section 8) during the data transfer period 1254. Therefore, as shown in FIG. 23A(b), only step-like measurement signals are obtained intermittently from measurement period 1258. As shown in FIG. 23A(c), the signal processing unit 42 converts the intermittently step-like measurement signal into a continuous one using a sample hold method. At this stage, as shown in FIG. 23A(c), the measurement signal changes discontinuously in a stepwise manner.

The measurement signal that changes discontinuously in a stepwise manner as shown in FIG. 23A(c) is smoothed using an optimized multiplex parallel bandpass filter. Furthermore, as shown in FIG. 23A(e), the DC component in the waveform of FIG. 23A(d) is removed to generate first extraction information 1218.

FIG. 23B shows a signal processing (data processing) process up to the information extraction 1004 of the second extraction information 1018 using the signal processing (data processing) method of FIG. 21A. FIG. 23B(a) shows an example of the format of the measurement signal sent from the signal receiving section 40. The measurement period 1258 and the data transfer period 1254 are time-divided and transferred. FIG. 23B(b) shows time-series data for each measurement wavelength in the spectral characteristic signal or time-series data for each pixel in the image sensor, and measurement in the spectral characteristic signal for each pixel in the image sensor included in the data cube. It represents time-series data 1200 for each wavelength. Since the data transfer period 1254 is not measured, it is sent as intermittent rectangular (pulse-like) time-series data.

FIG. 23B(c) shows the waveform of the first extracted information 1218 extracted 1004 in FIG. 23A(e). FIG. 23B(d) represents the result of multiplication for each time series between FIG. 23B(b) and FIG. 23B(c). The waveform in FIG. 23B(d) matches the output waveform of the multiplication processing unit 1230 for each wavelength or pixel. Since there is a period in which the waveform in FIG. 23B(c) takes a "negative value," there is also a period in which the waveform in FIG. 23B(d) takes a "negative value."

FIG. 23B(e) shows the result of the second extracted information 1018 extracted 1004 in FIG. 21A. When the DC component of the discrete signal in FIG. 23B(d) is extracted using the action of the time-series DC component extraction unit (ultra-narrow band low-pass filter) 1236 for each wavelength or pixel in FIG. 21A, the result is as shown in FIG. 23B. A constant value that does not depend on the elapsed time 1250 as shown in (e) can be obtained.

Section 7.5 Example of Demonstration Experiment Results The results of measuring spectral characteristics in a pulsating blood flow using the circuit configuration described in FIG. 21A will be described below. FIG. 24A shows the optical arrangement inside the light source section 2 used for measurement. The optical system described in FIG. 4 and the optical system described in FIG. 18A were combined using a dichroic mirror 350. Here, a laser beam with an emission wavelength of 1330 nm was used.

An SI type multimode single-core fiber SF with a core diameter of 0.6 mm guided this combined light to the tip 360 of the index finger. Another SI type multimode single-core fiber SF with a core diameter of 0.6 mm guided the light that passed through the index finger tip 360 (light scattered within the index finger tip 360) to the spectrometer in the measurement unit 8.

FIG. 24B(a) shows the spectral characteristics of the light irradiated onto the index finger tip 360. The amount of light emitted at the laser light emission wavelength (1330 nm) is overwhelmingly large. Note that the long wavelength side of the emitted light from the halogen lamp HL is blocked by a dichroic mirror 350.

FIG. 24B(b) shows the spectral characteristics of the light transmittance of transmitted light that has passed through the index finger tip 360 (light that has repeatedly been scattered inside the index finger tip 360 and then exited from the opposite side of the index finger tip 360).
In terms of light transmittance, the spectrometer was able to detect a sufficient amount of light even for 1330 nm wavelength light (laser light).

FIG. 25A shows the temporal change in relative light transmittance detected by a spectrometer. Here, the value obtained by dividing the light transmittance obtained from actual measurement data by the light transmittance that does not change over time measured in advance in FIG. 24B(b) is defined as relative light transmittance. This relative light transmittance was then used on the vertical axis of FIG. 25A. The horizontal axis in FIG. 25A shows the passage of time in 0.1 second increments. Therefore, every time the time elapsed value advances by 10, one second passes. Since a sufficient amount of light with a wavelength of 1330 nm (laser light) could be detected, a signal from this wavelength light can be used as the first extraction information 1218 (FIG. 20A or FIG. 21A).

FIG. 25A(a) (top curve) shows the relative light transmittance of 1330 nm wavelength light (laser light) over time. When blood vessels expand in response to pulsation, the amount of light absorbed by water increases, so the relative light transmittance decreases. From FIG. 25A(a), periodic changes in light transmittance around 1 second can be seen. This periodic light transmittance change is considered to be synchronized with pulsation.

As explained in FIG. 10A, glucose (carbohydrate) has an absorption peak within the wavelength range of 0.9 μm to 1.0 μm. Similarly, proteins exhibit absorption peaks within the wavelength range of 0.95 μm to 1.1 μm. FIG. 25(b) (bold curve) shows the relative light transmittance over time at a wavelength of 1026 nm, which is expected to be absorbed by the peptide skeleton. Further, FIG. 25(c) (lowest curve) shows the temporal change in relative light transmittance at a wavelength of 928 nm, which is expected to be absorbed by glucose.

For ease of explanation, the form of the second extracted information 1018 in FIG. 21A is not taken, but the raw signal waveform obtained from the measurement unit 8 is shown. As is clear from comparing FIGS. 25(b) and 25(c), the signal amplitude obtained from the 928 nm wavelength light is larger than the signal amplitude obtained from the 1026 nm wavelength light.

FIG. 25B shows the result of adding measurement data using light of other wavelengths. In FIG. 24B(b), the light transmittance of the DC component is lowest at a wavelength of 971 nm. Therefore, as shown in FIG. 25B(d), a signal obtained from light with a wavelength of 971 nm is also shown. The signal amplitude obtained from light with a wavelength of 971 nm (FIG. 25B(d)), where the DC component of light transmittance was the smallest, is the same as the signal amplitude obtained from light with a wavelength of 1026 nm, where the DC component of light transmittance is relatively large (Fig. 25B(d)). It is slightly larger than FIG. 25B(b)). From the above explanation, it can be seen that the amplitude of change in relative light transmittance synchronized with pulsation changes with the measurement wavelength.

Chapter 8 Section 8.1 Embodiment of combination of light source section and measurement section with built-in image sensor In Section 7.2, internal structure of image sensor and data acquisition timing in this embodiment, a length measurement method using laser pulses is explained. explained. The amount of light that reaches a long distance is inversely proportional to the square of the distance from the light emitting point. Therefore, when measuring a distance at a large distance, a sufficiently large amount of light emission is required. Those in the vicinity of this light-emitting point are exposed to extremely high intensity laser beam irradiation, increasing the risk of eye damage. In order to reduce the risk of damage to the eyes, it is desirable to use near-infrared laser light for length measurement, as explained in Section 4.1.

FIG. 26A shows the structure of a 3D (dimensional) color image sensor 1280 (capable of length measurement). Various optical filters 1272 to 1278 are arranged on the surface of each pixel 1262 to be imaged, and wavelength restrictions are applied to light that can reach each pixel 1262 to be imaged.

That is, an optical filter 1272 that transmits only red light and near-infrared light is installed immediately in front of pixels 1262-1 and 1262-2 that detect red light and near-infrared light. Immediately before the pixels 1264-1 and 1264-2 that detect green light and near-infrared light, an optical filter 1274 that transmits only green light and near-infrared light is installed. Furthermore, an optical filter 1276 that transmits only blue light and near-infrared light is installed immediately before the pixels 1266-1 and 1266-2 that detect blue light and near-infrared light. Similarly, an optical filter 1278 that transmits only white light and near-infrared light is installed immediately before the pixels 1268-1 and 1268-2 that detect white light and near-infrared light. Here, near-infrared laser light is used for length measurement using laser light.

FIG. 26B shows (the equivalent circuit of) the electronic circuit within this 3D color image sensor 1280. Preamplifiers 1150-1 and 2 are individually connected to pixels 1262-1 and 2 that detect red light and near-infrared light, respectively. Furthermore, preamplifiers 1150-3 and 4 are individually connected to pixels 1264-1 and 2 that detect green light and near-infrared light. During the exposure period, charges are accumulated in capacitors 1160-1 to 1160-4 according to detection signals from each preamplifier 1150-1 to 1150-4.

The interlocking switches 1300-1 and 1300-2 are independently turned ON/OFF depending on the exposure time and non-exposure time. The ON/OFF timing of these interlocking switches 1300-1 and 1300-2 is controlled by exposure timing setting circuits 1292-1 and 2. Here, during exposure, interlocking switches 1300-1 and 1300-2 are separately turned off, and charges are stored in capacitors 1160-1 to 1160-4 corresponding to preamplifiers 1150-1 to 1150-4 individually. Furthermore, during non-exposure, the interlocking switches 1300-1 and 2 are disconnected separately, and the detection signals from the pixels 1262-1 and 2 and 1264-1 and 2 in the 3D color image sensor 1280 are emitted toward the ground wire. Ru. At the same time, the charges stored in capacitors 1160-1 to 1160-4 are discharged.

Envelope detection circuits 1288-1 to 4 are individually connected to each preamplifier 1150-1 to 1150-4. At the end of exposure, the output voltages of the envelope detection circuits 1288-1 to 1288-4 are temporarily stored in the page memories 1296-1 and 1296-2. The output voltage data temporarily stored in the page memories 1296-1 and 1296-2 is periodically transferred to the outside via the readout circuit 1290.

In the electronic circuit of FIG. 26B, the detection signal is temporarily stored in the page memories 1296-1 and 1296-2 at each exposure timing. By arranging page memories 1296-1 and 1296-2 capable of storing detection signals at each exposure timing, an effect is produced in which detection signals during a very short exposure period can be stably detected.

FIG. 26C shows the control timing of the exposure timing setting circuit 1292 in FIG. 26B. The exposure period in FIG. 26B (i.e., the period during which the preamplifier 1150 continues to transmit the detection signal from the pixel 1264 in the 3D color image sensor to the envelope detection circuit 1288 by accumulating the charge in the capacitor 1160) is defined as τ. Then, the connection of the interlocking switch 1300 is cut off (FIG. 26C(b)) only while time elapses from time t1 to t1+τ (FIG. 26C(a)).

FIG. 26C(c) shows the timing at which the output of the envelope detection circuit 1288 is taken into the page memory 1296. In this way, immediately after the exposure period τ ends, the image is captured into the page memory 1296.

FIG. 26C(d) shows the output signal waveform of the envelope detection circuit 1288 before and after the exposure period. Before the exposure period, the amount of charge accumulated in the capacitors 1160-1 to 1160-4 is "0", so the output signal of the envelope detection circuit 1288 maintains the state of "0". When the exposure period begins, charge begins to accumulate in capacitors 1160-1 to 1160-4, so the output signal of envelope detection circuit 1288 begins to increase. Immediately after the exposure period τ ends, the charges in the capacitors 1160-1 to 1160-4 are discharged, but the envelope detection circuit 1288 maintains the state immediately before the exposure period τ ends.

FIG. 26C(e) shows data taken into page memory 1296. The data in the page memory 1296 before the exposure period τ has an initial value of “0”. Immediately after the exposure period τ ends, the exposure timing setting circuit 1292 issues a data capture instruction to the page memory 1296. At the timing of this data capture instruction, the output data of the envelope detection circuit 1288 is captured into the page memory 1296. This captured data is delivered to readout circuit 1290 at appropriate timing.

Section 8.2 Embodiment of Combination of Measurement Unit with Built-in Image Sensor and Light Source Unit FIG. 27A shows a combination of measurement unit 8 with built-in 3D color image sensor 1280 and light source unit 2 described in the previous Section 8.1. An example embodiment of an optical system is shown. As an example of the detailed structure inside the light source section 2 used here, a combination of FIGS. 18A and 18B may be used. By using the external synchronization signal line 730 in FIG. 18B, highly accurate time coordination regarding the exposure period τ of the image sensor 1280 can be achieved. However, the present invention is not limited to this, and any structure of the light source section 2 including that shown in FIG. 9I may be used.

As explained in Section 5.4 using FIG. 17B, the amount of speckle noise is significantly reduced as the number of angular divisions increases within the optical characteristic changing element 210. However, it is difficult to completely remove the amount of speckle noise. Therefore, in this embodiment, a structure that can be slightly movable with respect to the traveling direction of the emitted light from the light source section 2 may be added. As explained in Section 5.1 using FIG. 13, the speckle noise pattern changes depending on the irradiation angle to the measurement target object 22. Therefore, by changing the irradiation angle onto the measurement object 22 over time and time-averaging (or time-integrating) the measurement results, the amount of speckle noise can be further reduced.

In FIG. 27A, a light reflecting plate 520 is placed in the optical path of the emitted light from the light source section 2, and the inclination angle of the light reflecting plate 520 is slightly moved using piezoelectric elements 526 and 528. Based on this, the irradiation angle to the measurement target object 22 is changed over time.

A half mirror 536 is disposed within the measurement unit 8, and a portion of the reflected light from the measurement object 22 (not shown) reaches the 3D color image sensor 1280. An imaging lens moving mechanism 540 moves the imaging lens 144 along the optical axis direction. Due to the function of this imaging lens moving mechanism 540, the 3D color image sensor 1280 can be placed at an imaging position for the measurement target 22 located at an arbitrary position.

A two-dimensional array optical shutter 530 is installed at the same imaging position as the 3D color image sensor 1280. This two-dimensionally arrayed optical shutter 530 may be configured with any optical shutter such as a liquid crystal shutter. When this two-dimensional array optical shutter 530 is used, measurement accuracy is improved when near-infrared light is used for length measurement using the 3D color image sensor 1280.

As explained in Section 4.1 using FIG. 10A, water absorbs near-infrared light. In particular, water absorbs a large amount of light having a wavelength exceeding 1.3 μm. Therefore, in rainy or foggy environments, the accuracy of length measurement using near-infrared light decreases. In particular, when the surface of the measurement object 22 becomes wet, the amount of near-infrared light reflected therefrom decreases.

A method of using the two-dimensional array optical shutter 530 will be explained. First, when the amount of near-infrared light emitted from the light source section 2 is set to "0", a color image obtained from the measurement object 22 is measured using the 3D color image sensor 1280. The outline of the obtained color image is extracted, and the shape of the measurement object 22 when observed with visible light is grasped. Next, when the near-infrared light emitted from the light source section 2 is continuously emitted, an image obtained from the 3D color image sensor 1280 is collected. By comparing the images with and without light emission from the light source section 2, the moisture absorption distribution on the surface of the measurement object 22 can be determined. When a pattern that corrects the moisture absorption distribution on the surface of the measurement object 22 is applied to the two-dimensional array optical shutter 530, the influence of the moisture absorption distribution on the surface of the measurement object 22 can be reduced.

In FIG. 27A, a two-dimensionally arrayed optical shutter 530 is arranged within the measurement section 8, and the light source section 2 and the measurement section 8 are arranged in close proximity. However, the present invention is not limited thereto, and the light source section 2 and the measurement section 8 may be arranged at separate positions. For example, in FIGS. 31B, 30B, and 30C, which will be described later, the light source section 2 and the measurement section 8 are arranged at separate positions. In this case, a light reflecting plate 520 including piezoelectric elements 526 and 528 and a two-dimensionally arranged optical shutter 530 may be built into the light source section 2.

FIG. 27B shows the control circuit configuration of the 3D color image sensor 1280. Using this control circuit configuration, it is possible to not only reduce the influence of the moisture absorption distribution on the surface of the measurement object 22, but also realize highly accurate length measurement. A light emission timing control section 1302 within the light emission amount control section 30 controls the light emission amount of near-infrared light within the light source section 2 described above. A non-emission color image (video) storage section 1316 in the signal receiving section 40 stores a color image (video) collected by the 3D color image sensor 1280 in the measurement section 8 when the light source section 2 is not emitting light.

Next, the light emission timing control section 1302 in the light emission amount control section 30 performs continuous light emission control of the near-infrared light in the light source section 2 described above. At the same time, a color image (video) storage section 1318 that includes the light source wavelength light in the signal receiving section 40 stores the color image (video) collected by the 3D color image sensor 1280 at this time.

The difference calculation processing unit 1314 in the signal processing unit 42 extracts the difference in color images (videos) depending on whether or not the light source unit 2 emits light. An image (video) storage unit 1312 of only the light source wavelength light in the signal processing unit stores the difference result. The saved contents are then transferred to the pattern setting unit 1304 of the two-dimensionally arrayed optical shutter in the light emission amount control unit 30. The pattern setting unit 1304 of the two-dimensionally arrayed optical shutter controls the transmitted light amount distribution characteristics of the two-dimensionally arrayed optical shutter 530.

The control circuit in FIG. 27B not only performs this but also performs various timing controls that will be described later from FIG. 28A onwards. An exposure timing setting section 1310 in the signal receiving section 40 performs various timing controls to be described later. At the same time, a light emission timing control section 1302 in the light emission amount control section 30 controls the light emission timing of the light source section 2 in accordance with a command from the internal system control section 50.

In addition to the structure in which the light source section 2 and the measurement section 8 coexist in the light source device 10 shown in FIG. 27B, in this embodiment, the light source section 2 and the measurement section 8 are arranged at physically separate positions, and are connected via the Internet. Both may be connected. In this case, Internet communication may be performed between the light source section 2 and the measurement section 8 (via the host 50) using the method described in Section 6.4.

The content of the measurement using the combination of the 3D color image sensor 1280 and the light source section 2 uses the 3D color image (video) in the application field (various optical application fields) compatible section 60 (duplicated description in FIG. 1 and FIG. 27B). It is used by application software 58. An example of how the application software 58 is used using this 3D color image (video) will be described later in Chapter 9 below. However, it is not limited to the service provision content described later in Chapter 9, and may be used for any service provision content.

Also, in this Chapter 8, embodiments that mainly utilize the 3D color image sensor 1280 will be described. However, the present invention is not limited thereto, and any charge storage type signal receiving section may be used as other embodiments (including those described in Section 7.3, for example).

Section 8.3 Distance Measurement Procedure FIG. 28A shows a method for measuring a three-dimensional color image (video) with high accuracy. Note that for convenience of explanation, the expression "three-dimensional color image (video) measurement" is used here. Therefore, as an alternative embodiment to the embodiment described in this Section 8.3 and the following Section 8.4, any charge storage type signal receiver and light source (including, for example, the content described in Section 7.3) may be used. Part 2 may be combined. In addition, the procedure described in Section 8.3 can be used in conjunction with the "correction process for the detected light characteristic distribution obtained from the measurement object 22 when irradiated with light at the emission wavelength of the light emitting source 2" described in the previous Section 8.2. (performed before or after the correction process).

In FIG. 28A, a plurality of light emission patterns 750 (a plurality of light irradiation patterns to the measurement target object 22) in the light source section 2 are used. This difference in the light emission pattern 750 may be notified to the light source section 2 in advance using the light emission pattern identification information 750 (FIG. 19C) in the control signal 790.

In this embodiment, length measurement is possible over a very wide range, such as a 100 m range or a 1 km range. It is difficult to measure the length within such a wide measurement range at once with high precision. For example, it takes time to achieve high-precision measurement with a measurement error of 1 mm or less over a wide area, such as 1 km, in just one measurement. Further, high measurement accuracy is required only near the location where the measurement target object 22 exists. On the other hand, in a place where there is no object 22 to be measured, high-precision measurement has little meaning.

Therefore, there is a method of first ascertaining the approximate distance to the measurement object 22 over a wide range, and then performing high-precision measurement near the measurement object 22. In this way, by dividing the measurement into multiple times and changing the measurement range and measurement accuracy in stages, the overall measurement efficiency is improved. The optimum light emission pattern 750 may be switched depending on the range to be measured and the required accuracy. By combining measurements using a plurality of light emitting patterns 750 in this way, it is possible to measure the length of the object 22 to be measured with high accuracy even at a far away position.

Three different light emission patterns 750 (a plurality of light irradiation patterns to the measurement target object 22) may be used between the start (ST10) and the end (ST17) of collecting three-dimensional color images (videos). In the two-dimensional color image (video) collection in step 11, a light emission pattern described later with reference to FIG. 28B(b) is used. Using the image (video) obtained from the light emission pattern, in step 12, a reflected light pattern of the light source wavelength light over the entire measurement distance range is imaged.

In collecting a two-dimensional color image (video) in the next step 13, a light emission pattern described later in FIG. 28C(b) is used. Using the image (video) obtained from the light emission pattern, in step 14, a reflected light pattern of the light source wavelength light is imaged for each measurement distance range.

In the subsequent two-dimensional color image (video) collection in step 15, a light emission pattern described later in FIG. 28D(b) is used. Then, in step 16, detailed distance measurement is performed for each measurement distance range using the image (video) obtained from the light emission pattern.

FIG. 28B shows a method of imaging a reflected light pattern with light source wavelength light over the entire measurement distance range. The intensity of emitted light from one light emitting point is inversely proportional to the square of the distance from the light emitting point. Further, when measuring the distance to the measurement object 22 using reflected light from the measurement object 22, the distance from the light source section 2 to the measurement section 8 increases to twice the distance to the measurement object 22. Therefore, the maximum amount of light emitted from the light source section 2 is determined by the measurement range (the maximum distance from the light source section 2 that can be measured). Further, when the measurement target object 22 is moved away from the object 22, it is necessary to increase the amount of light emitted from the light source section 2.

FIG. 28B(b) shows a light emission pattern suitable for imaging a total reflection light pattern over the entire measurement distance range. During the light emitting period from time t1 to t2, light is emitted continuously, and the amount of light emitted decreases along a quadratic curve as time passes. Accordingly, uniform light reflection characteristics can be collected over the entire measurement distance range.

FIG. 28B(c) shows the exposure timing in the measurement unit 8 (3D color image sensor 1280). Immediately after the light emission stop time t2 of the light source section 2, exposure is performed for a period of τ (a rectangular wave period). During this exposure period τ, the light that left the light source section 2 Δt1 and Δt2 before returns together. Regarding the measured distance Δx, there is a relationship of Δx=cΔt/2 (c: speed of light in air). Therefore, the measurement distance range in this case is measured up to a distance of c(t2-t1)/2. From the image acquired at the exposure timing shown in FIG. 28B(c), a total reflection light pattern over the entire measurement distance range can be seen. By comparing the image obtained here (total reflection light pattern over the entire measurement distance range) with the image obtained in FIG. Distance can be determined. Note that all the images acquired in the explanation from FIG. 28B to FIG. 28E refer to images stored in the image (video) storage section 1312 of only the light source wavelength light in the signal processing section 42 shown in FIG. 27B.

FIG. 28C shows a method of imaging a reflected light pattern using light source wavelength light for each measurement distance range. The light source section 2 emits intermittent pulsed light as shown in FIG. 28C(b). This intermittent pulsed light emission is performed in a constant cycle at times t1, t2, and t3. An interference prevention period 798 of a predetermined period is provided within this fixed period, and the light source section 2 is controlled so as not to emit light during this interference prevention period 798. If no light emission is controlled within this interference prevention period 798, erroneous distance measurement based on pulsed light emission at wrong timing can be prevented, and measurement accuracy is improved.

Furthermore, the amount of light emission is changed at each light emission timing t1, t2, and t3. The phenomenon in which the amount of detection signals from the distant measurement target 22 decreases has been described above. By changing the amount of light emitted for each measurement distance range to be measured in this way, changes in measurement accuracy for each measurement distance range are prevented, and stable distance measurement over the entire measurement distance range is possible.

FIG. 28C(b) shows a rectangular pulsed light emission state. However, the present invention is not limited thereto, and light may be emitted using a "modulation signal unique to the light source section 2 (ID information signal of the light source section 2)" during the pulse emission period. In a system in which a plurality of light emitting units 2 are arranged at the same location, there is a risk that the light emission state from different light emitting units 2 will be erroneously detected within the measuring unit 8 (3D color image sensor 1280 thereof). Another photodetection element 250 may be arranged within the measurement section 8, and this another photodetection element 250 may simultaneously detect a unique modulation signal (ID information signal of the light source section 2) that is different for each light source section 2. When the detection of a modulation signal specific to the light source section 2 using another photodetection element 250 is also used, unnecessary light emission pulses mixed in from another light emitting section 2 within the exposure period τ within the target measurement section 8 can be detected. Accordingly, the risk of false detection in a system in which a plurality of light emitting units 2 are arranged at the same location is significantly reduced.

FIG. 28C(c) shows the exposure timing in the measurement unit 8 (3D color image sensor 1280). The delay times Δt1, Δt2, and Δt3 of the exposure timing in the measurement unit 8 (3D color image sensor 1280) with respect to the light emission timing in the light source unit 2 are different for each light emission time t1, t2, and t3. The measurement distance range is changed by changing this delay time. In Figure 28C,
Δt1<Δt2<Δt3. However, the present invention is not limited thereto, and each delay time may be arbitrarily set as long as there is a difference of a certain value or more between the delay times Δt1, Δt2, and Δt3. Therefore, it is also possible to set Δt1>Δt2>Δt3.

Each image acquired at each timing and during the same exposure period τ shows a part of the image acquired in FIG. 28B. Therefore, by comparing each image acquired here with the image acquired in FIG. 28B, it is possible to grasp the approximate distance of each region into which the total reflection light pattern over the entire measurement distance range is finely divided.

FIG. 28D shows a detailed distance measurement method within each measurement distance range. The interference prevention period 798 is set in the light emission state of the light source section 2 (FIG. 28D(b)), and the delay times Δt1 and Δt2 of the exposure period τ are changed at each light emission time t1 and t2 of the light source section 2 (FIG. 28D(b)). 28D(c)) is consistent with FIG. 28C.

As shown in FIG. 28D(b), the part that causes the light source section 2 to emit modulated light intermittently is different from FIG. 28C(b). In the period of intermittent light amount modulation in FIG. 28D(b), "uniform periodic light emission" is desirable. Furthermore, when modulating the light amount, it is desirable that the duty ratio be 50%. As long as this light emission state satisfies the conditions of "uniform period" and "50% duty ratio", light may be emitted with any waveform. For example, a sine wave, a rectangular wave, a triangular wave, etc. may be freely set.

FIG. 28E shows an explanatory diagram of a distance measurement method using the phase detection method. The structure inside the 3D color image sensor 1280 has been described using FIG. 26A. For distance measurement here, four pixel sets 1262-1, 1264-1, 1266-1, and 1268-1 are used. Further, each exposure timing is shifted in accordance with the modulated light emission state of the light source section 2 described above.

FIGS. 28E(b) to (e) show the exposure timing for each of the four pixels 1262, 1264, 1266, and 1268. Here, the exposure periods τ of the four pixels 1262, 1264, 1266, and 1268 are all made to match. Then, the exposure timing is shifted by the exposure period τ. Then, as shown in FIG. 28E(f), the modulated light emission period of the light source section 2 is set to "4τ".

When the detection light in FIG. 28E(g) is shifted by phase φ with respect to the reference modulated light emission state in FIG. 28E(f), the page memory 1296 (FIG. 26B) The amount of signals input to corresponds to the area values of A1, A2, A3, and A4.
Therefore

から、検出光の遅延位相量φが算出できる。この方法を用いて、精度よく計測部８（内の３Ｄカラー撮像素子１２８０）に戻る検出光の遅延量が分かる。

From this, the amount of delay phase φ of the detection light can be calculated. Using this method, the amount of delay of the detection light returning to the measurement unit 8 (3D color image sensor 1280 therein) can be determined with high precision.

For example, if the technology of Patent Document 3 is used, even now it is possible to capture an image with an exposure period τ as short as “1 nS”. The period of the reference modulated light emission in FIG. 28E(f) is 4τ=4nS. Assuming that the speed of light in the air is approximately 3×10 ⁸ m/S and that the round-trip light to the measurement object 22 is detected, the above period is 3×10 ⁸ ×4×10 ⁻⁹ ÷2 = 0.6 m. becomes. Therefore, during the exposure period τ=1 nS, it is possible to measure a change in the longitudinal position within a measurement distance range of 60 cm. The length measurement accuracy in this case is determined by the area accuracy of areas A1 to A4 in FIG. 28E(g). Therefore, the optical noise reduction techniques described in Chapters 2, 3, and 5 are extremely important.

Speckle noise can be significantly reduced using the method described in Section 8.4 Method for reducing the influence of laser speckle noise on measurements. However, as shown in FIG. 17B, even if the number of angular divisions of the optical characteristic changing element 210 is significantly increased, it is difficult to completely eliminate speckle noise. Chapter 7 explained a high-precision measurement method that combines optical noise reduction technology and circuit technology.

FIG. 28F shows a method for further reducing the effects of speckle noise by combining circuit techniques. Here, optical noise reduction measures such as the description in Chapter 7 in the light source unit 2, the explanation in Section 8.2 using Figure 27A, and the explanation in Section 3.3 using Figure 9I are introduced. It is assumed that the execution of However, the present embodiment is not limited thereto, and only the embodiment described below may be implemented without performing optical noise reduction.

FIG. 27F(b) shows the light emitting state in the light source section 2. The pulsed light emission explained in FIG. 28C(b) starts from time t2. However, as explained using FIG. 28C(b), light emission modulation may be performed during this pulse light emission period. From the subsequent time t4, the modulated light emission explained in FIG. 28D(b) is performed.

Within the detection unit 8 (the 3D color image sensor 1280 thereof), each has an exposure period τ at a different timing. The signals detected during the exposure period τ at different timings are stored separately in the page memory 1296 (FIG. 26B) as separate signals. In FIGS. 28F(c) to (e), to simplify the explanation, only the exposure period τ corresponding to only one pixel 1262 is shown. However, in reality, as shown in FIGS. 28G and 28H, the exposure start time is shifted by the exposure period τ for each pixel 1262 to 1268.

FIG. 27F(c) shows the timing of the first exposure period τ in (the 3D color imaging device 1280 of) the detection unit 8. This first exposure period τ starts from time t1 before the light source section 2 emits light. During this first exposure period τ, a color image (video) of only visible light is captured with the light source section 2 in a non-emission state. The image (video) obtained here matches the content of the image (video) stored in the non-emission color image (video) storage unit 1316 in FIG. 27B.

FIG. 27F(d) shows the timing of the second exposure period τ in (the 3D color image sensor 1280 of) the detection unit 8. The second exposure period τ starts at a time t3 delayed by _Δt0 from the time t2 when the light source section 2 starts emitting pulsed light. During this second exposure period τ, an image (image) is obtained in which a reflected image (image) of the light of the emission wavelength of the light source unit 2 irradiated with pulsed light emission is superimposed on a color image (image) obtained from visible light. . This image (video) matches the content of the image (video) stored in the color image (video) storage unit 1318 including the light source wavelength light in FIG. 27B.

The second exposure period τ in the detection unit 8 (3D color imaging device 1280 thereof) starts Δt ₀ after the light source unit 2 starts emitting pulsed light. This time difference of Δt ₀ means that reflected images (images) of light of the emission wavelength of the light source unit 2 at positions separated by Δx ₀ =cΔt ₀ /2 are superimposed. The actual pulse emission period of the light source section 2 is much longer than the second exposure period τ in (the 3D color image sensor 1280 of) the detection section 8. Therefore, the location where the reflected image (video) of the light emitted from the light source 2 is superimposed is at a position Δx ₀ =cΔt ₀ /2−δ that is shorter than Δx ₀ =cΔt ₀ /2 by δ. The reflected images (images) of the light emitted at wavelengths are superimposed.

The important point here is that "speckle noise is mixed in the reflected image (video) of the light emitted by the light source 2 at the wavelength". The speckle noise mixing rate differs between the four pixels 1262, 1264, 1266, and 1268 that make up one set. In this second exposure period τ, an image (video) mixed with speckle noise is obtained for each pixel 1262 to 1268.

Each of the areas A1 to A4 shown in FIG. 28E(g) shows an ideal state without speckle noise. However, in reality, the influence rate of speckle noise (rate of change in amount of light caused by speckle noise) differs for each pixel 1262 to 1268. Therefore, when the influence of speckle noise is taken into consideration, the levels A1 to A4 in FIG. 28E(g) individually vary greatly due to the influence of speckle noise. Here, within a very short time range, the influence rate of speckle noise for each pixel 1262 to 1268 (rate of variation in light amount caused by speckle noise) is constant regardless of the amount of light emitted by the light emitting unit 2. In other words, speckle noise for each pixel 1262 to 1268 occurs when the light emitting pattern in the light emitting unit 2 is in a modulated light emitting state as shown in FIG. It is considered that the influence rate (rate of light amount fluctuation caused by speckle noise) is almost the same.

When looking at the short exposure period τ within the pulse emission period with a rectangular wave, it can be considered that light is emitted with a constant amount of light within the exposure period τ. Therefore, in this embodiment, the influence rate of speckle noise (light intensity variation caused by speckle noise) for each pixel 1262 to 1268 is obtained during the second exposure period τ in the detection unit 8 (3D color image sensor 1280). The second information corresponding to the "phase information obtained from the measurement object 22" is extracted using this first extraction information.

FIG. 27F(e) shows the timing of the third exposure period τ in (the 3D color imaging device 1280 of) the detection unit 8. This third exposure period τ starts at time t5, which is delayed by _Δt0 from time t4 when the light source section 2 starts modulated light emission. Due to the description on the paper, the interval between time t3 and time t4 in FIG. 28F is narrow. However, in reality, the interval between time t3 and time t4 is sufficiently wide. During this third exposure period τ, an image (image) is obtained in which a reflected image (image) of light of the emission wavelength of the light source unit 2 irradiated with modulated light is superimposed on a color image (image) obtained from visible light. . The reflected image (video) of light of the emission wavelength of the light source unit 2 includes "phase component information obtained from the measurement object 22." Further, this "phase information obtained from the measurement object 22" is buried in "speckle noise for each pixel 1262 to 1268." Therefore, by using the first extracted information acquired in the second exposure period τ, ``the influence rate of speckle noise for each pixel 1262 to 1268 (rate of light amount variation caused by speckle noise)'', speckle noise "Phase component information obtained from the measurement target object 22" (second information) buried in the measurement object 22 is extracted 1000 (FIG. 20A).

FIG. 28G shows detection signals for each pixel obtained in the first exposure period and the second exposure period. FIGS. 28G(b) to (e) show detection signals obtained by four pixels 1262 to 1268 forming one set during the first exposure period τ. Red intensity b1, blue intensity b2, green intensity b3, and white intensity b4 in the color information collected in the first exposure period τ are obtained individually. Furthermore, the exposure period τ is shifted by τ for every four pixels 1262 to 1268.

FIGS. 28G(f) to (i) show detection signals obtained by four pixels 1262 to 1268 forming one set during the second exposure period τ. Here again, the exposure period τ is shifted by τ for every four pixels 1262 to 1268. When there is no speckle noise, the amount of reflected light Δhi (1≦i≦4) with respect to the light emitted by the light source 2 that is added to the intensity bi (1≦i≦4) of each color in the color information shows approximately the same value. . However, when the speckle noise is large, the amounts of reflected light Δh1, Δh2, Δh3, and Δh4 added for each of the four pixels 1262 to 1268 differ greatly.

FIG. 28H shows detection signals for each pixel obtained in the second exposure period and the third exposure period. FIGS. 28H(f) to (i) match FIGS. 28G(f) to (i). FIGS. 28H(j) to (m) show detection signals obtained by four pixels 1262 to 1268 forming one set during the third exposure period τ. Here too, the exposure period τ is shifted by τ for every four pixels 1262 to 1268. The values ΔL1, ΔL2, L3, and ΔL4, in which the phase component information obtained from the measurement object 22 corresponding to the modulated light emission of the light source unit 2 is buried in speckle noise, are the respective color intensities bi (1≦i≦ 4).

When the time difference t5-t3 between the start time t3 of the second exposure period τ and the start time t5 of the third exposure period τ is sufficiently small, the “influence rate of speckle noise for each pixel 1262 to 1268 ( It is assumed that ΔLi and Δhi (1≦i≦4) are almost the same. Then, the actual phase component Ai after removing the influence of speckle noise is:
It can be calculated as Ai=ΔLi/Δhi (1≦i≦4). In this way, by using the first extraction information (influence rate of speckle noise for each pixel 1262 to 1268 (rate of light amount fluctuation caused by speckle noise)) obtained in the second exposure period τ, the third extraction information is extracted. The second information (substantive phase component Ai) mixed in the signal obtained during the exposure period τ can be extracted. With this method, the influence of residual noise (such as residual speckle noise) after optical noise reduction described in Chapters 2, 3, and 5 can be further removed.

Section 8.5 Hyperspectral Detection Method Using Irradiation Wavelength Control FIG. 29A shows the basic cross-sectional structure of the linear variable bandpass filter 190. The thickness of the optical thin film 194 formed on the transparent substrate 192 changes depending on the location. When panchromatic light (light containing light with different wavelengths) 188 is made incident on this linear variable bandpass filter 190, it undergoes multiple reflections between the interface between the surface of the optical thin film 194 and the transparent substrate 192. As a result, the wavelengths of the transmitted lights 198-1 to 198-4 change depending on the location.

FIG. 29B shows an embodiment of a hyperspectral detection method configured by combining this linear variable bandpass filter 190 and a 3D color image sensor 128 having the structure shown in FIG. 26A. A linear variable band pass filter moving mechanism 196 moves the linear variable band pass filter 190 as time progresses. Therefore, the wavelength of the light passing through the pinhole 310 placed at the focusing position of the focusing lens 330 changes with time.

The light passing through this pinhole 310 illuminates the measurement object 22 (not shown) via the imaging lens 144. A portion of the reflected light from the measurement object 22 is reflected by the half mirror 536 and is directed toward the 3D color image sensor 128 . The imaging lens moving mechanism 540 moves the imaging lens 144 in the optical axis direction, and aligns the position of the 3D color image sensor 128 with the imaging position of the measurement target 22.

The light source section 2 emits panchromatic light and emits light intermittently. The 3D color image sensor 128 collects color images regarding the measurement object 22 during the non-emission period of the light source section 2. Further, during the light emission period of the 3D color image sensor 128 and the light source section 2, an image in which a reflected light image of the wavelength light passing through the linear variable band pass filter 190 and a color image are superimposed is collected. The difference in light intensity between the two images becomes a hyperspectral data cube signal.

By using the embodiment shown in FIG. 29B, near-infrared spectral characteristics for each pixel can be obtained simultaneously with a color image. Therefore, there is no need to align the color image and the hyperspectral data cube image, which has the effect of improving user convenience.

For example, a heat emitting filament such as a halogen lamp or a mercury lamp may be used as the light emitting section 470 in the light source section 2 that emits panchromatic light. However, because the electrical response speed inside the heat-emitting filament is slow, intermittent light emission at high speeds is difficult.

An improved form of the structure in FIG. 11A will be described as an example of this embodiment as a structure of the light source section 2 that can emit panchromatic light capable of high-speed response. The emission wavelength of the semiconductor laser device 500 used as the second light emitting source 170 is set to 1250 nm or less, and is used as an excitation light source for the near-infrared emitting phosphors 162 and 164. In this case, the arrangement of the first light emitting source 160 (LED light source) within the light emitting section 470 may be omitted. The fluorescent substances 182 to 186 used in the near-infrared emitting phosphors 162 and 164 are materials with a short fluorescence half-life (materials that emit fluorescence immediately after excitation and stop emitting fluorescence immediately after excitation light irradiation is stopped). ). By appropriately selecting the material, a light emitting section 470 with a fast response speed for fluorescent light emission can be realized.

Note that the method for extracting light of a predetermined wavelength from the panchromatic light emitted from the light source section 2 is not limited to the use of the linear variable bandpass filter 190. For example, the predetermined wavelength light may be extracted from the panchromatic light by any method such as using a general optical filter, a variable transmission wavelength Fabry-Bello resonator, or mechanically tilting the spectroscopic element 320.

When the light source section 2 having the above structure is arranged as shown in FIG. 29B and operated in conjunction with the 3D color image sensor 1280 in the manner described in Sections 8.1 to 8.4, the near-infrared spectral characteristics of the measurement object 22 can be changed. Simultaneously with the measurement, three-dimensional measurement of the surface irregularities of the measurement object 22 becomes possible. In other words, by controlling the light emission of the light source section 2 in conjunction with the control section 8 and controlling the wavelength of the emitted light from the light source section 2, it is possible to simultaneously measure the spectral characteristics of the measurement object 22 and the distance to the measurement object 2. . Furthermore, if the above measurement is performed for each pixel arranged two-dimensionally (or one-dimensionally), simultaneous measurement at a plurality of different positions on the measurement object 2 becomes possible. Furthermore, as explained in Section 4.4, it is possible to downsize the light source section 2 or the measurement section 8. Therefore, it has a very compact structure and has the effect of easily collecting a wide variety of information at once.

Chapter 9 Service Provision Section 9.1 Examples of Input/Output Device Forms When Providing Services FIG. 30A is an explanatory diagram of examples of input devices and output devices necessary for using a predetermined service providing domain. As an example of an embodiment of a method of providing services to users or a system of providing services to users, there is a method of constructing a predetermined service providing domain 1058 in cyberspace and allowing users to use it.

In order for the user 1080 to use the predetermined service providing domain 1058 in the cyberspace, the end user 1080 needs the input device 1060 and output device 1070 necessary for using the predetermined service providing domain 1058 in the cyberspace.

In a personal computer, a keyboard and a mouse are mainly used as input devices 1060. Further, in a smartphone, a touch screen corresponds to the input device 1060. Touch screens have a greater variety of functions than keyboards. In this embodiment, automatic image (video) input technology or automatic voice input technology may be used as an input method with improved functional diversity, operability, and convenience compared to the touch screen. That is, the image (video) collection function and the audio information collection function are used as the device classification 1062 regarding the input device 1080 in this embodiment. A microphone is an input device type 1064 that collects this audio information. Further, as the input device form 1064 having an image (video) collection function, the 3D color camera 1280 described in Chapter 8 or the visible color camera that can simultaneously measure near-infrared spectral characteristics can be used.

When the input device 1080 is a 3D color camera 1280 or a visible color camera that can simultaneously measure near-infrared spectral characteristics, the user's body movements can be used as an information input method (data usage purpose 1068). For example, the user's gestures and finger actions may be used in place of the existing mouse. In this case, a gesture interpretation function, a fingertip command interpretation function, and a virtual three-dimensionalization function may be provided within the input device 1060 or within the host 50 connected to the input device.

When inputting information using a visible color camera that can also measure near-infrared spectral characteristics at the same time as the input device 1060, it is possible to analyze the composition forming the living body that appears in the near-infrared spectral characteristics. Therefore, it may be used for personal authentication using biometric information such as vein authentication. Furthermore, it becomes possible to automatically detect biological activities based on temporal changes in near-infrared spectral characteristics. For example, it becomes possible to automatically recognize the feelings and emotions of the end user 1080 within the host 50 based on the state of contraction of facial expression muscles of the end user 1080. Further, as explained in Section 7.5, the composition analysis in the blood of the end user 1080 may be performed from outside in a non-invasive or non-contact manner. For example, it becomes possible to automatically input the user's physical condition using blood sugar level measurement results. Furthermore, the excited state of the end user 1080 can be input in real time based on the adrenaline content in the blood.

Output device classification 1062 based on the functions that can be realized by the output device 1070 includes a three-dimensional display function, a modeling function, an audio information output function, a tactile stimulation device function, etc. As part of this tactile stimulation functionality, end user 1080 movement inhibition functionality may be included. For example, when the end user 1080 carries heavy luggage in the real world, the degree of freedom of movement is restricted. This freedom of movement constraint imposed on the end user 1080 upon entering the predetermined service provision domain 1058 in cyberspace may be implemented as part of this tactile stimulation device functionality.

As the output device form 1074 that realizes the stereoscopic display function, a thin stationary display screen or a portable display device such as VR (virtual reality) or AR (augmented reality) may be used. Furthermore, a 3D printer may be used as an output device with a modeling function. A speaker can be used to output audio information, and the skin epidermis pressurizer has a tactile stimulation function.

30B and 30C show an input device 1060 and an output device 1070 used in this embodiment. In FIG. 30B, a thin stationary display screen (wall-mounted stereoscopic display or computer display stereoscopic display) 900 is used as an embodiment of the output device 1070 used as the display unit 18. In addition, one light source section 2 and a plurality of measurement sections 8 are disposed in a part of this thin stationary display screen 900 or a part of the outside thereof (outer frame of a wall-mounted 3D display or a 3D display for computer display) 902. There is. This set of one light source section 2 and a plurality of measurement sections 8 corresponds to the input device 1060. FIG. 30B uses the embodiment example of the light source section 2 and measurement section 8 described up to Chapter 8. In particular, by arranging a plurality of measuring units 8 at different positions, stereoscopic images (stereoscopic images) can be collected from multiple angles.

Lenticular lenses (fine cylindrical lenses) are arranged horizontally on the surface of the thin stationary display screen (wall-mounted 3D display or computer display 3D display) 900. The measurement unit 8 then measures the three-dimensional position of the end user's 1080 eyeball in real time. Then, according to the eyeball position of the end user 1080 (by eye tracking), each pixel of the thin stationary display screen (wall-mounted 3D display or computer display 3D display) 900 is individually divided into an image for the right eye and an image for the left eye of the end user 1080. Create an image. The lenticular lens also controls the direction of the right and left eye images toward the end user's 1080 right and left eyes. Then, a virtual stereoscopic image is displayed to the end user 1080 by utilizing the difference in convergence angle of each image, which has a different virtual position in the front-rear direction captured by the right eye and left eye.

The virtual keyboard visible in the foreground in FIG. 30B shows an example of display using the above method. Moreover, three-dimensional measurement can be performed by the combined operation of the light source section 2 and the measurement section 8. Therefore, the three-dimensional position of each of the ten fingertips of the end user 1080 can be measured in real time. For example, when the end user 1080 places both hands on a three-dimensionally displayed virtual keyboard and moves ten fingers, a virtual key-in operation becomes possible.

FIG. 30C shows another example embodiment regarding input device 1060 and output device 1070. As an embodiment of the output device 1070 corresponding to the display unit 18, AR glasses 820 and 830 capable of stereoscopic display are used. These AR glasses 820 and 830 display a right-eye image (video) and a left-eye image (video) separately, and perform stereoscopic display using the above-mentioned difference in convergence angle. Note that instead of the AR glasses 820 and 830, VR glasses may be used.

FIG. 30C(b) shows an example in which a virtual keyboard placed a predetermined distance away from the end user 1080 is displayed as a stereoscopic display screen (image). The end user 1080 looks at this virtual keyboard and keys in the virtual keyboard while moving his ten fingers. A brooch 810 with a built-in 3D color image sensor fixed to the breast pocket of the end user 1080 has a light source section 2 and a measuring section 8, and the emitted light from the light source section 2 is reflected by the fingertip of the end user 1080. The measurement unit 8 uses the reflected light from the fingertips to measure a 3D color image (video) including the three-dimensional positions of the ten fingertips in real time.

The end user 1080 carries on his back a backpack 850 that includes a power supply unit, a control unit 50, and a communication function for external communication. This backpack 850 supplies power to the AR glasses 830 (display section 18) via a connection cable 866. The backpack 850 also generates a right eye image (video) and a left eye image (video) and transmits them to the AR glasses 830 via the connection cable 866.

At the same time, this rucksack 850 supplies power to the brooch 810 with a built-in 3D color image sensor via the connection cable 866. The measurement unit 8 also transmits the three-dimensional image (three-dimensional video) collected by the measurement unit 8 to the backpack 850 via the connection cable 876. The signal processing unit 42 in the backpack 850 analyzes this three-dimensional image (three-dimensional video) and estimates the movements of the ten fingertips of the end user 1080. Then, using this estimation result, the position within the virtual keyboard where the end user 1080 keyed in is determined. If three-dimensional measurement using the 3D color image sensor 1280 can be performed in real time in this way, a variety of information can be input into a predetermined service providing domain 1058 in cyberspace using the movements of the end user 1080. Furthermore, since information input can be performed using only finger actions, the burden on the end user 1080 is greatly reduced. Providing the input device 1060 with a three-dimensional measurement function in this manner has the effect of greatly improving the convenience for the end user 1080.

In the embodiment shown in FIG. 30C(b), a backpack 850 with a built-in control unit 50 including connection cables 866 and 876, a brooch 810 with a built-in 3D color camera (built-in light source unit 2 and measurement unit 8), and a display unit 18 are supported. The entire AR glasses 830 constitute the optical device 10 (FIG. 1). Further, in the embodiment shown in FIG. 30C(a), a shoulder bag 840 with a built-in control unit 50 including connection cables 860 and 870, a pendant or necklace 800 with a built-in 3D color camera (with built-in light source unit 2 and measurement unit 8), and a display unit The entire AR glasses 820 corresponding to the optical system 18 constitute the optical device 10 (FIG. 1). The functions of each device and the data content transferred between devices in FIG. 30C(a) match those in FIG. 30C(b). In FIG. 30C(a), a pendant or necklace 800 with a built-in 3D color camera includes a light source section 2 and a measurement section 8, and has the function of the measurement section 8.

A virtual image 1400 in the virtual space, such as a virtual keyboard displayed as if placed a predetermined distance away from the end user 1080, is defined within a predetermined service providing domain 1058 in cyberspace. The virtual image 1400 in this virtual space has a three-dimensional structure, and its position and shape change over time (that is, it becomes a virtual four-dimensional structure). In this embodiment, a virtual image 1400 in a virtual space defined (regulated) within a predetermined service providing domain 1058 in cyberspace and displayed to an end user 1080, and a real object in the real world such as the finger of the end user 1080 are used. 1410 operate in conjunction with high precision.

In order to realize highly accurate interlocking operations, it is important to align the virtual image 1400 in virtual space and the real object 1410 in the real world in three-dimensional directions. As a specific method for the alignment, for example, a method of ``aligning the position of the virtual image 1400 in the virtual space with the position in the real world in three-dimensional directions based on the real object 1410 in the real world'' may be performed. .

FIG. 30C(a) shows an example of a scene where the end user 1080 is performing alignment in the three-dimensional direction. Specifically, the position and display size of the virtual image 1400 in the virtual space are adjusted using the left hand (real object 1410) of the end user 1080 as a reference. This alignment uses the movement of the index finger of the end user's 1080 right hand.

FIG. 31A shows both the real object 1410 in the real world that the end user 1080 sees during the above alignment and the virtual image 1400 in the virtual space, superimposed. The measurement unit 8 in FIG. 30C(a) has a built-in 3D color image sensor 1280. Therefore, this measurement unit 8 images (photographs) the left hand of the end user 1080 in real time. Then, the display screen within the AR glasses 820 capable of stereoscopic display displays the imaged (photographed) left hand of the end user 1080 as a virtual image 1400 in virtual space. Regarding the left hand of the same end user 1080, FIG. 31A(a) shows an example in which the virtual image 1400 in the virtual space is displayed larger than the real object 1410.

FIG. 31A(b) shows the right hand of end user 1080 existing as real object 1410. For example, with respect to the distance between the thumb and index finger of the right hand, move the distance ``faster to shorten the distance and slower to widen the distance''. Then, the measuring unit 8 in FIG. 30C(a) captures an image of the movement, and the signal processing unit 42 (FIG. 1) interprets it as an "instruction to reduce the size of the virtual image 1400 in the virtual space."

To change the display position of virtual image 1400 in virtual space,
A) The direction of movement is defined by the direction of the pad of the right index finger (opposite the nail) of the end user 1080,
B) Difference in the speed of extension and contraction of the right index finger of the end user 1080 (difference between the speed of bending the finger and the speed of stretching the finger)
You may also use Here, the measuring unit 8 in FIG. 30C(a) measures the distance in the front-back direction to the real object 1410 (the left hand of the end user 1080) in real time. Further, in FIG. 31A(a), a real object 1410 related to the left hand of the same end user 1080 and a virtual image 1400 in virtual space are displayed in an overlapping manner. Therefore, the distance in the front-rear direction of the virtual image 1400 in the virtual space may be automatically adjusted to the distance in the front-rear direction to the real object 1410 (the left hand of the end user 1080). When the alignment between the real object 1410 and the virtual image 1400 in the virtual space is completed, an "OK mark" is displayed with the fingertip of the right hand (real object 1410) of the end user 1080 as shown in FIG. 31A(c). good. Then, this "enter information" is transferred to the predetermined service providing domain 1058 in cyberspace.

Instead of adjusting the display position and display size of the virtual image 1400 in the virtual space using the method shown in FIG. 31A(b), the position and size of the virtual keyboard can be adjusted using both hands of the end user 1080 of the real object 1410 as shown in FIG. 31A(d). May be specified.

FIG. 31A shows an example of generating input information to a predetermined service providing domain in cyberspace using a user's finger action. The relationship between the movement of the user's finger, the shape of the finger, and the input information is not limited to the above, and may be set arbitrarily. In addition, not only the movement of the user's fingers but also the movement of the user's entire body (gesture), the movement and expression of the user's face, and any other method using the real object 1410 can be used to provide a predetermined service in cyberspace. Information input to the provided domain may also be realized.

It was explained that the input device 1060 for the predetermined service providing domain 1058 in cyberspace shown in FIG. 30A can use near-infrared light. The basic functions 1066 of the input device 1060 using this near-red light include biological measurement and emotion prediction. In addition, the data usage purpose 1068 collected by the input device 1060 using this near-infrared light can be compositional analysis forming a living body and personal authentication.

FIGS. 31B and 31C show an example of a usage mode when near-infrared light is used as the input device 1060. FIG. 31B shows an example of a usage environment of an input device 1060 that uses near-infrared light. The predetermined light 230 emitted from the light source section 2 includes near-infrared light. The measurement unit 8 then measures the reflected light from the measurement target object 22.

FIG. 31C shows an enlarged view of the usage environment example shown in FIG. 31B. As explained in Section 4.1 using FIG. 10A, light with a wavelength exceeding 1.3 μm is largely absorbed by water in the living body. Therefore, when the palm 23 is irradiated with light with a wavelength exceeding 1.3 μm, the blood vessel region 600 is observed to stand out. There are individual differences in the patterns of the blood vessel regions 600, and therefore, the differences in the patterns of the blood vessel regions 600 can be utilized for personal authentication.

Section 9.2 Service Provision Example FIG. 32 shows an embodiment of a service provision method for an end user 1080 using a time-operable service provision domain 1500. This time-manipulable service providing domain 1500 is located in a part of the predetermined service providing domain 1058 in cyberspace described above. Furthermore, when using this time-manipulable service providing domain 1500, daily charges may be made. If the service provision domain 1500 that allows time manipulation is used over multiple days, billing for the next day will be required at the time the user uses the service providing domain 1500 that allows time adjustment over multiple days. Internet communication charges are required to enter the cyberspace 1058 using the input device 1060 and the output device 1070. The fee for using the service providing domain 1500 that allows time adjustment on a daily basis may be added to this Internet communication fee.

A user 1450 (end user 1080) in real space performs an entry procedure 1506 before entering a service providing domain 1500 that allows time manipulation. At the beginning of this specific entrance procedure 1506, personal authentication using the biometric authentication described in the previous section using FIGS. 31B and 31C is performed. Next, the user 1450 (end user 1080) in the real space is asked whether or not the daily admission fee can be automatically debited. When the user 1450 (end user 1080) in the real space approves the automatic withdrawal of the daily admission fee, entry into the time-manipulatable service providing domain 1500 is permitted. A user who enters the time-manipulable service provision domain 1500 changes from a user 1450 in real space to a user in cyberspace. Here, the user in this cyberspace is referred to as an end user 1080.

At the entrance to the time-manipulable service providing domain 1500, a usage menu within the time-manipulable service providing domain 1500 is displayed. A user 1450 (end user 1080) in real space makes a desired menu selection 1528. A first channel progression 1530 then begins over time.

End users 1080 within time-enabled service provision domain 1500 can transition to second channel progression 1540 via menu selection 1528. Here, the inside of the display section 18 may be divided into multiple screens. By dividing multiple screens, the first channel progress 1530 and the second channel progress 1540 can be displayed simultaneously. By using this multiple screen simultaneous display function, the end user 1080 has the effect of being able to operate within the service providing domain 1500 where time can be manipulated efficiently. Since the user 1450 has only one body in real space, multiple experiences cannot be performed at the same time. However, in the service providing method shown in this embodiment, the end user 1080 in cyberspace can receive multiple experiences at the same time. With this multiple screen simultaneous display function, the end user 1080 can be provided with services that are not available in real space.

If a daily billing method is adopted, the end user 1080 can enter and leave the service providing domain 1500, which allows time manipulation, multiple times during the same day. When the user 1450 in real space has an emergency and temporarily leaves 1510 from the service providing domain 1500 where time can be manipulated, the end user 1080 returns to user 1450 in real space. Here, consider a case where the end user 1080 temporarily leaves 1510 from the service providing domain 1500 in which time can be manipulated when the elapsed time 1498 is _tR .

When the user 1450 in the real space finishes work 1520 outside the service providing domain and re-enters 1512, the elapsed time 1498 advances within the service providing domain 1500 where time can be manipulated, and the time 1498 is much later than the time _tR . The user re-enters 1512 the service providing domain 1500 where the time can be manipulated.

In this embodiment, at this re-entry time 1512, the user may return to time _tR in the service providing domain 1500 where time can be manipulated. Then, by using the fast forward playback function 1546, the end user 1080 can follow up on events that occurred within the service providing domain 1500 in which the time can be manipulated during the work 1520 period outside the service providing domain. In this way, within the time-manipulable service providing domain 1500 shown in this embodiment, "services that transcend time and space" can be provided to the end user 1080.

In particular, the input device 1060 used in this embodiment can perform distance measurement (surface unevenness characteristic measurement) with high precision for a measurement target 22 that is sufficiently far away, such as 100 meters away or 1 km away. Therefore, by using the zoom function of the display screen, it is possible to instantly display the object 22 to be measured 1 km away as if it were very close. By using such a zoom display function, it is possible to provide the end user 1080 with the experience of "instantaneous transportation" as a "service that transcends space."

The input device 1060 shown in this embodiment can be made smaller and lighter. Therefore, the input device 1060, which is smaller and lighter, may be built into the drone, for example. This allows input of captured images (videos) from the sky. By using this captured image (video) from the sky, it is also possible to provide "services that transcend gravity" to the end user 1080. In other words, the service providing domain 1500 that allows time manipulation may provide the end user 1080 with the experience of flying in the sky or floating in the air.

The service providing domain 1500 that allows time manipulation may charge an additional admission fee at the timing of switching from the first day of admission 1502 to the second day of admission 1504. At this switching timing, the service providing domain 1500 that can manipulate the time displays an "inquiry about next day admission fee payment" to the end user 1080. When the end user 1080 performs "Next Day Admission Fee Payment Approval 1550", the service within the time-operable service providing domain 1500 is continued.

Section 9.3 Data format example of 4-dimensional data obtained by measurement
In this Section 9.3, for example, only the data format of the four-dimensional image (video) information obtained from the 3D color image sensor 1280 will be explained. Audio information collected during imaging with the 3D color image sensor 1280 may use an existing audio recording format. The playback synchronization with the audio information during playback of the four-dimensional image (video) information may be performed using time-related information 1702 in the data format, which will be described later.
FIG. 33A shows an example of local coordinate axes viewed from the 3D color image sensor 1280. Here, a Zl coordinate axis is defined in the perpendicular direction of the 3D color image sensor 1280. Then, coordinate axes of Xl and Yl are defined along the arrangement direction of the image sensors 1262 to 1268. Furthermore, the imaging time is defined as Tl.

In this embodiment, the position information input from the 3D color image sensor 1280 is defined as a position on a four-dimensional coordinate axis, which is three-dimensional spatial position information plus a time axis. By expressing the measurement results in four-dimensional coordinates including the time axis Tl in this way, it is possible to manage a variety of information including the movement and time-series shape changes of the measurement object 22 such as video (video). is born.

FIG. 33B shows an example of the data format of four-dimensional data obtained from the surface of the measurement target object 22. The 3D color image sensor 1280 collects information on the four-dimensional coordinates and RGBW intensities (red intensity, green intensity, blue intensity, and white intensity in color information) of each point on the surface of the measurement object 22.

Each point on the surface of the measurement object 22 is defined by a node 1600. For finely uneven parts on the surface of the measurement object 22, the intervals between the nodes 1600 are set narrowly. Further, in the rough portion of the uneven shape, the intervals between the nodes 1600 are set wide. Furthermore, the four-dimensional coordinate values of each node are defined by the coordinate axes in FIG. 33A. The form of expression of the surface shape of the measurement object 22 expressed by this set of nodes 1600 is called a "mesh".

Here, the surface image of the measurement object 22 expressed in the form of a mesh at a predetermined time (when the value on the time axis is fixed) is referred to as a "mesh frame". In this embodiment, multiple mesh frames are defined. That is, in the "mesh frame I (image)" shown in FIG. 33B(a), the four-dimensional coordinates and RGBW intensities of all nodes 1600-1 to 1600-8 are managed. On the other hand, in the "mesh frame P (progress)" shown in FIG. 33B(b), the information of only the node 1600 that has information different from the mesh frame I described above or the difference of only the node 1600 that has information different from the mesh frame I is shown. Manage only value information.

For example, compared to FIG. 33B(a), FIG. 33B(b) shows an example in which a positional shift occurs only between node 1_1600-1 and node 4_1600-4. In this case, the management information of mesh frame P is managed only by the information of node 1_1600-1 and node 4_1600-4 (or the difference value from the information of node 1_1600-1 and node 4_1600-4 in mesh frame I). be done. As a difference between FIG. 33B(b) and FIG. 33B(a), a change in the positions of node 1_1600-1 and node 4_1600-4 is illustrated. However, the information is not limited to this, and even when only a change in color intensity occurs, it is managed as information within the mesh frame P. By reducing the information of the mesh frame P compared to the mesh frame I in this way, an effect is created in which the management information of the four-dimensional video according to time changes can be significantly reduced.

FIG. 33C shows an example of management information for the node 1600 defined in units of mesh frames 1610 and 1620. This example of management information is based on the mesh structure of each mesh frame 1610 and 1620 shown in FIG. 33B. This management information includes mesh frame information 1700 that is managed in units of mesh frames 1610 and 1620, and node information 1800 that is managed for each node within the same mesh frame.

The time information captured by the 3D color image sensor 1280 for each mesh frame 1610 and 1620 is in the format of "year/month/day/hour/minute/second/second decimal point information" as time-related information (measurement information, etc.) 1702. recorded. This information may be used for playback synchronization with audio information performed during playback of this four-dimensional image (video) data. PTS (presentation time stamp) is used for synchronization during playback of general AV (audio and video) information. If this PTS is to be displayed in synchronization with defined audio information, this information may be converted into PTS and synchronized.

In this embodiment, multiple types of mesh frames are defined. In the column of frame type information 1704, for example, is it "I frame"? Is it "P frame"? Identification information is recorded.
For example, as explained in the previous section (section 9.2) using FIG. Information 1800 can be obtained. Therefore, this frame type information 1704 can provide processing convenience for fast-forward playback 1546.

In this embodiment, frame numbers 1706 are set for multiple types of mesh frames. Using this frame number 1706 improves the convenience of temporal access processing such as time search to the elapsed time 1498 specified by the end user 1080.

The frame number of the mesh frame referenced by the relevant mesh frame is stored in the reference frame 1708 column. Mesh frame I_1610 may be designated as this "reference mesh frame". As specified in FIG. 33B, the node information 1800 in mesh frame P_1620 has only difference information from mesh frame I_1610. Therefore, when the relevant mesh frame is mesh frame P_1620, all the node information 1800 can be obtained by combining the node information 1800 corresponding to this relevant mesh frame and the nod information 1800 in the reference frame 1708.

Difference time information 1710 with reference time indicates a difference value between time-related information 1702 of the applicable mesh frame and time-related information 1702 of the mesh frame (mesh frame I_1610) referred to by the applicable mesh frame.

The number of intensity bits (dynamic range) 1714 represents the number of bits representing the various color information intensities 1812 to 1818 in the nod information 1800. If the value of the number of intensity bits (dynamic range) 1714 is increased, the various color information intensities 1812 to 1818 can be expressed in fine gradations, but the data size of this management information increases.

The number of connected nodes, 1720, represents the representation format state of the mesh structure. In FIG. 33B, three nodes 1600 constitute a triangular basic cell. The #1 node 1600-1 is connected to the #2 node 1600-2, the #4 node 1600-4, the #3 node 1600-3, the #6 node 1600-6, and the #5 node 1600-5. It is connected to five nodes 1600. Therefore, in the representation format state of the mesh structure in FIG. 33B, the number of connected nodes 1720 is "5". However, the basic cell is not limited thereto, and for example, the basic cell may be formed of a rectangle. In this case, the number of connected nodes 1720 takes a different value.

The total number of nodes 1720 indicates the number of nodes 1600 managed within the corresponding mesh frames 1610 and 1620. Further, the data size 1718 indicates the data size of the node information 1800 regarding the node 1600 managed within the corresponding mesh frame 1610, 1620. Here, if the data size of the node information 1800 regarding one node 1600 is expressed as P and the total number of nodes is expressed as N, then this data size 1718 is given by N×P.

All the nodes 1600 in all the mesh frames 1610 and 1620 are set with serial numbers. Therefore, all nodes 1600 within mesh frames 1610, 1620 are identified and managed by this node number 1802. Therefore, this nod number 1802 is placed at the first position in the nod information 1800. Further, in this embodiment, only the nodes 1600 that have changed from mesh frame I_1610 are managed within mesh frame P_1620. Therefore, by simply searching for the node number 1802 of the node 1600 managed within the mesh frame P_1620, the question ``Which node 1600 has changed?'' will appear in the mesh frame I_1610. ” can be easily searched.

In the representation format of the mesh structure in FIG. 33B, #1 node 1600-1 is #2 node 1600-2, #4 node 1600-4, #3 node 1600-3, and #6 node 1600-6. , #5, and the five nodes 1600 of node 1600-5. This connection relationship is then written in the connection node number 1804 connected to the corresponding node 1600. Using this information, it becomes easy to analyze the detailed uneven shape of the surface of the measurement target 22.

The X coordinate value 1806, Y coordinate value 1808, and Z coordinate value 1810 indicate the three-dimensional coordinate value of the corresponding node 1600. Further, each of white intensity 1812, red intensity 1814, green intensity 1816, and blue intensity 1818 indicates color information of the reflected light from the corresponding nod 1600.

Section 9.4 Mapping processing
The virtual space within the service providing domain 1500 where time can be manipulated is often managed using a four-dimensional map. By managing with a four-dimensional map that adds a temporal axis to three spatial dimensions, it becomes easier to search for past history and search for playback using the elapsed time 1498.

For example, as an example of an embodiment, consider a case where a plurality of end users 1080 hold a conference in the virtual space of the service providing domain 1500 where the time can be manipulated. It is assumed that the conference room in the virtual space of the time-manipulatable service providing domain 1500 allows six people to attend the conference with a virtual desk in the center. In the conference room in this virtual space, a common four-dimensional coordinate axis 1828 within the map is set in advance, as shown in the embodiment of FIG. 34A. The Xc axis and Yc axis within this four-dimensional coordinate axis 1828 are aligned with the corner direction of the virtual desk. Further, the Zc axis points above the conference room in the virtual space. Further, the conference holding time is defined along the time axis Tc. Furthermore, a presentation screen 1822 is arranged in this conference room, and an illumination light (lighting condition in the map 1826) is arranged at the lower right of FIG. 34A.

FIG. 34B shows the processing steps leading to the generation of a right-eye image (video) and a left-eye image (video) to be displayed on the output device 1070 using a four-dimensional map within the time-operable service providing domain 1500. From the start (ST20) to the end (ST31) of the process in FIG. 34B, processes from synthesizing the three-dimensional image (video) on the map to displaying the three-dimensional image (video) to the end user 1080 are performed. Note that, as shown in FIG. 33B, a management unit for each frame (one image in a video) is called a mesh frame, and a mesh frame spanning multiple frames is collectively called 4-dimensional mesh data from FIG. 34B onwards.

First, a series of processing steps will be outlined using FIG. 34B. After that, specific processing contents will be explained using FIGS. 34C to 34E. Since the content of this series of processing is complex, it may be difficult to understand the content from only the explanation of FIG. 34B. It becomes easier to understand intuitively by using FIGS. 34C to 34E, which will be described later.

In imaging with only one 3D color image sensor 1280, imaging can only be performed from one direction of the measurement target 22 to be imaged. However, if a plurality of measurement units 8 disposed at different positions are used simultaneously, as shown in FIG. 30B, for example, it becomes possible to capture images of the measurement target 22 from multiple angles. In this way, when the same measurement object 22 is imaged from multiple directions, the obtained plural image (video) information is synthesized as shown in step 21, and the same measurement object 22 is imaged. 4D mesh data can be created.

Next, the end user 1080 selects a map to be used within the time-operable service providing domain 1500 (ST22). This map selection means selection of the conference room you want to use. However, this map selection step (ST22) is not limited to conference room selection, but includes all map selections used within the time-operable service providing domain 1500. For example, if a sightseeing trip within the service provision domain 1500 in which time can be manipulated is selected, four-dimensional map information of a tourist spot may be selected.

This map selection (ST22) also includes designation of a location (occupied location 1830) that the end user 1080 wants to occupy within the selected map.

A common four-dimensional coordinate axis 1828 within the map is defined for each map selected by the end user 1080. Further, the 3D color image sensor 1280 that captures the image of the end user 1080 has the unique coordinate axes described with reference to FIG. 33A defined therein. Therefore, in step 24, coordinate conversion processing is performed from the coordinate axes unique to the 3D color image sensor 1280 to the common four-dimensional coordinate axes 1828 in the map in accordance with the occupied location 1830 designated by the end user 1080. Immediately after this, in step 25, color intensity adjustment is performed in accordance with the intra-map lighting conditions 1826.

When the coordinate transformation (ST24) and color intensity adjustment (ST25) for each end user 1080 are completed, the four-dimensional mesh data of each end user 1080 is synthesized on a map as a rendering process (ST26). Through the rendering process on this map, a plurality of different end users 1080 can gather at a specific location within the service providing domain 1500 where time can be manipulated.

In the subsequent step 27, the viewpoint position when displaying to each end user 1080 on the map is set. Then, all the mesh data rendered on the map is again subjected to coordinate transformation in accordance with this viewpoint position and viewpoint direction (ST28). Then, using all the mesh data after this coordinate transformation, in step 29, images (videos) of the right eye and left eye are generated in accordance with the user's eyeball position.

The right eye and left eye images (video) generated in step 29 are displayed on the output device 1070 to display the 4D image (video) to the end user 1080.

FIG. 34C is an explanatory diagram of the step of converting coordinates from the four-dimensional coordinate axes 1838 for each location in accordance with the common four-dimensional coordinate axes in the map. This step is a diagram explaining in detail the process of step 24 in FIG. 34B.

FIG. 34C shows an example of a state in which a specific end user 1080 is seated facing forward in a seat at occupied location #2_1830-2 in a virtual conference room. It is necessary to perform image processing (rendering processing) so that another meeting attendee (another end user 1080) can see this particular end user 1080 seated facing forward.

As an environment for capturing an image of the specific end user 1080, consider a case where a three-dimensional color image sensor 1280 (measuring unit 8) installed facing the specific end user 1080 captures an image as illustrated in FIG. 30B. As shown in FIG. 33A, in the local Zl coordinate axis preset in this three-dimensional color image sensor 1280, the direction opposite to the direction of the face of this specific end user 1080 represents a "positive" direction. (In other words, the direction in which the face of this particular end user 1080 faces indicates the "negative direction" of the local coordinate axis Zl unique to the end user 1080.)
As shown in FIG. 34C, the "negative direction" of the local coordinate axis Zl unique to the end user 1080 coincides with the Yc direction in the common four-dimensional coordinate axes within the map. Therefore, it is necessary to coordinate the coordinate axes of the four-dimensional mesh data obtained by imaging this particular end user 1080 to match the common four-dimensional coordinate axes within the map.

Similarly, the directions of the local coordinate axes Xl, Yl, and Zl when the end user 1080 seated at occupied location #4_1830-4 is imaged by the three-dimensional color image sensor 1280, and the directions of the common four-dimensional coordinate axes Xc, Yc, and Zc in the map. The directions are different from each other.

In this way, the directions of the local coordinate axes Xl, Yl, and Zl in the four-dimensional mesh data collected by imaging the end user 1080 differ for each different occupied location 1830 selected by the end user 1080 within the same map. Therefore, coordinate transformation is performed to match the location of the occupied location 1830 selected by the end user 1080. As a result, the coordinate axes that serve as the reference for the four-dimensional mesh data collected by imaging all the end users 1080 are unified into the common four-dimensional coordinate axes Xc, Yc, and Zc within the map. Only when the reference coordinate axes of the 4-dimensional mesh data are unified to the common 4-dimensional coordinate axes Xc, Yc, and Zc within the map, it becomes possible to perform a rendering process to synthesize the 4-dimensional mesh data of all the members who participated in the meeting.

FIG. 34D is an explanatory diagram of the color intensity adjustment method performed in step 25 of FIG. 34B. For example, consider a case where the light emitting section 2 is placed on the left side of the sphere. The left side of the sphere, which is closer to the light emitting section 2, is illuminated by the emitted light from the light emitting section 2 and becomes brighter. On the other hand, the right side of the sphere, which is in the shadow of the light emitting part 2, becomes dark. In this brightly illuminated nod 1600, the intensity of each color increases and approaches the color of the emitted light from the light emitting section 2. Then, the intensity of each color of the nod 1600 in the dark part of the shadow decreases. Adjusting the color intensity of the nodes 1600 in the 4-dimensional mesh data according to the lighting conditions 1826 in the map (i.e., the position of external light and lights and the emitted light color of the lights) improves the reality of the image (video) displayed to the end user 1080. This has the effect of increasing.

FIG. 34E shows a detailed explanatory diagram regarding the setting of the viewpoint position on the map shown in step 27 in FIG. 34B. When a wearable display capable of stereoscopic display (VR/AR) is used as the output device 1070 for the end user 1080, front-back position information for each display object becomes very important. Therefore, depending on the user's display viewpoint position 1860 within the four-dimensional map, the front-back position direction of the stereoscopic display screen changes.

In this embodiment, the user's display viewpoint position 1860 and the direction in which the viewpoint faces can be set at any position within the service providing domain 1500 where time can be manipulated. Providing this function has the effect of dramatically improving the sense of realism of images (videos) provided to the end user 1080. For example, while watching a soccer match, it is possible to virtually run around with the soccer team members, or to watch the progress of the soccer match from the perspective of the referee.

As shown in FIG. 34E, in this embodiment, a user's display viewpoint 1860 and a four-dimensional coordinate axis 1868 at a display viewpoint that matches the direction of the user's viewpoint are defined. Here, the depth direction (back and forth direction) for stereoscopic display to the end user 1080 is set to the Zd axis. Further, the horizontal direction as viewed from the end user 1080 is set to the Xd direction.

Then, in step 28 of FIG. 34B, all the four-dimensional mesh data constructed on the common four-dimensional coordinate axes in the map are coordinate-transformed so that they become four-dimensional mesh data on the four-dimensional coordinate axes 1868 at the display viewpoint. After this, the stereoscopic image (video) generated (ST29 in FIG. 34B) is displayed to the end user 1080 (ST30 in FIG. 34B). At this time, the end user 1080 may request an enlargement (zoom) function for the displayed stereoscopic image (video). When the coordinates are converted in advance to four-dimensional mesh data on the four-dimensional coordinate axis 1868 at the display viewpoint in this way, an effect is created in which it becomes easier to quickly respond to the user's enlargement (zoom) request.

Although an embodiment of the invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. This embodiment and its modifications are included within the scope and gist of the invention, as well as within the scope of the invention described in the claims and its equivalents.

2... Light source section, 4... Information transmission path, 6... Light propagation path, 8... Measurement section, 10... Optical device,
12... Measuring device, 14... Service providing system, 16... External system, 18... Display unit,
20...Object, 22...Measurement object, 24...Optical control object,
26... Optical recording/reproduction medium, 28... Other light irradiation targets, 30... Light emission amount control unit,
32...recording signal generation section, 34...information/signal conversion section (including encryption/modulation processing),
40... Signal receiving section, 42... Signal processing section, 44... Signal/information converting section (including decoding/demodulation processing),
50... System internal control unit, 52... Various non-optical sensors,
60...Application field (various optical application fields) adaptation section, 62...Characteristic analysis/analysis processing section,
64... Manufacturing suitability control/processing section, 66... Monitoring control/management section, 68... Treatment suitability control/processing section,
70...Medical/Welfare Related Inspection Processing Department, 72...Information Providing Department, 74...Collected Information Storage Department,
76...Other various application compatible parts, 78...Long axis direction, 80...Service provision method,
82... Predetermined light utilization method, 84... Optical measurement unit, 86... Predetermined light generation method, 88... Minor axis direction,
90... Predetermined optical member, 92... Input surface of the predetermined optical member, 94... Output surface of the predetermined optical member,
96... Perpendicular to the incident surface side, 98... Perpendicular to the exit surface side,
110... Waveguide element (optical fiber/optical waveguide/light guide), 112... Core region,
114...Clad region, 116...Gravity center position of intensity distribution, 118...Light reflecting surface,
120...collimating lens or cylindrical lens,
122... Macroscopic entrance plane of a predetermined optical member, 124... Position within the optical fiber cross section,
126... Perpendicular to the macroscopic entrance surface, 128... Equiphase surface, 130... Wedge-shaped prism,
132...Position in the core region, 134...Position on the light collecting surface, 136...Light amplitude distribution,
138... Refractive index distribution, 140... Multi-segment Fresnel prism (predetermined optical member),
142...Fresnel lens or fly's eye lens, 144...imaging lens,
146... Stray light component, 148... Multi-divided light reflecting element (Fresnel type reflector), 152... Electric field distribution,
200...Initial light, 202...First light, 204, 208...Second light, 206...Third light,
210... Optical property conversion element, 212... First region, 214... Second region,
216... Third region, 220... Photosynthesis place, 222... First optical path, 224... Second optical path,
226...Third optical path, 230...Predetermined light, 240...Optical operation location,
300... line sensor (one-dimensional array detection cell array), 310... pinhole,
312...Half mirror plate, 314, 316...Folding mirror plate,
318... Collimating lens, 320... Spectroscopic element (reflection type blazed grating),
322, 324... Fθ lens or collimating lens, 330... condensing lens,
400...Initial wave sequence, 402...Phase asynchronization, 406...After wave field division, 408...Delay after division,
410...Photosynthesis processing, 420...Light intensity averaging, 470...Light emitting unit, 480...Optical property changing unit.

Claims (11)

In the first light and the second light emitted from the same light emitting part and passing through a predetermined optical member,
An entrance surface side perpendicular perpendicular to the entrance surface of the predetermined optical member and an exit surface side perpendicular perpendicular to the exit surface of the predetermined optical member are defined,
The traveling direction of the first light has an inclination angle between at least one of the normal to the incident surface side and the normal to the exit surface side,
The traveling direction of the second light is tilted with respect to the traveling direction of the first light, or the optical path of the second light within the predetermined optical member is made different from the optical path of the first light. . A predetermined light generation method that changes optical characteristics between the first light and the second light. In an optical property changing section including a predetermined optical member,
The first light and the second light emitted from the same light emitting part pass through the predetermined optical member,
An entrance surface side perpendicular perpendicular to the entrance surface of the predetermined optical member and an exit surface side perpendicular perpendicular to the exit surface of the predetermined optical member are defined,
The traveling direction of the first light has an inclination angle between at least one of the normal to the incident surface side and the normal to the exit surface side,
The traveling direction of the second light is tilted with respect to the traveling direction of the first light, or the optical path of the second light within the predetermined optical member is made different from the optical path of the first light. , an optical property changing unit that changes optical properties between the first light and the second light; In a light source composed of a light emitting part and a predetermined optical member,
The first light and the second light emitted from the same light emitting section pass through the predetermined optical member,
An entrance surface side perpendicular perpendicular to the entrance surface of the predetermined optical member and an exit surface side perpendicular perpendicular to the exit surface of the predetermined optical member are defined,
The traveling direction of the first light has an inclination angle between at least one of the normal to the incident surface side and the normal to the exit surface side,
The traveling direction of the second light is tilted with respect to the traveling direction of the first light, or the optical path of the second light within the predetermined optical member is made different from the optical path of the first light. , a light source that changes optical characteristics between the first light and the second light. In the first light and the second light emitted from the same light emitting part and passing through a predetermined optical member,
A perpendicular line to the entrance surface side that is perpendicular to the entrance surface of the predetermined optical member is defined,
The traveling direction of the first light has an inclination angle with the perpendicular to the incident surface side,
The traveling direction of the second light is tilted with respect to the traveling direction of the first light, or the optical path of the second light within the predetermined optical member is made different from the optical path of the first light. , after changing the optical characteristics between the first light and the second light,
A predetermined light utilization method that utilizes composite light obtained by combining the first light and the second light. In the first light and the second light emitted from the same light emitting part and passing through a predetermined optical member,
A perpendicular line to the entrance surface side that is perpendicular to the entrance surface of the predetermined optical member is defined,
The traveling direction of the first light has an inclination angle with the perpendicular to the incident surface side,
The traveling direction of the second light is tilted with respect to the traveling direction of the first light, or the optical path of the second light within the predetermined optical member is made different from the optical path of the first light. , after changing the optical characteristics between the first light and the second light,
Irradiating a measurement target with a composite light obtained by combining the first light and the second light,
A detection method for detecting third light obtained from the measurement target. In the first light and the second light emitted from the same light emitting part and passing through a predetermined optical member,
A perpendicular line to the entrance surface side that is perpendicular to the entrance surface of the predetermined optical member is defined,
The traveling direction of the first light has an inclination angle with the perpendicular to the incident surface side,
The traveling direction of the second light is tilted with respect to the traveling direction of the first light, or the optical path of the second light within the predetermined optical member is made different from the optical path of the first light. , after changing the optical characteristics between the first light and the second light,
Irradiating a measurement target with a composite light obtained by combining the first light and the second light,
An imaging method that performs imaging using third light obtained from the measurement target. In the first light and the second light emitted from the same light emitting part and passing through a predetermined optical member,
A perpendicular line to the entrance surface side that is perpendicular to the entrance surface of the predetermined optical member is defined,
The traveling direction of the first light has an inclination angle with the perpendicular to the incident surface side,
The traveling direction of the second light is tilted with respect to the traveling direction of the first light, or the optical path of the second light within the predetermined optical member is made different from the optical path of the first light. , after changing the optical characteristics between the first light and the second light,
A display method that uses composite light obtained by combining the first light and the second light for display. The optical measurement section includes a light emitting section and a predetermined optical member,
The first light and the second light emitted from the same light emitting section pass through the predetermined optical member,
A perpendicular line to the entrance surface side that is perpendicular to the entrance surface of the predetermined optical member is defined,
The traveling direction of the first light has an inclination angle with the perpendicular to the incident surface side,
The traveling direction of the second light is tilted with respect to the traveling direction of the first light, or the optical path of the second light within the predetermined optical member is made different from the optical path of the first light. , after changing the optical characteristics between the first light and the second light,
Irradiating a measurement target with a composite light obtained by combining the first light and the second light,
An optical measurement unit that measures the measurement target using third light obtained from the measurement target. In an optical device composed of a light emitting part and a predetermined optical member,
The first light and the second light emitted from the same light emitting part pass through the predetermined optical member,
A perpendicular line to the entrance surface side that is perpendicular to the entrance surface of the predetermined optical member is defined,
The traveling direction of the first light has an inclination angle with the perpendicular to the incident surface side,
The traveling direction of the second light is tilted with respect to the traveling direction of the first light, or the optical path of the second light within the predetermined optical member is made different from the optical path of the first light. , after changing the optical characteristics between the first light and the second light,
An optical device that utilizes composite light obtained by combining the first light and the second light. In the first light and the second light emitted from the same light emitting part and passing through a predetermined optical member,
A perpendicular line to the entrance surface side that is perpendicular to the entrance surface of the predetermined optical member is defined,
The traveling direction of the first light has an inclination angle with the perpendicular to the incident surface side,
The traveling direction of the second light is tilted with respect to the traveling direction of the first light, or the optical path of the second light within the predetermined optical member is made different from the optical path of the first light. , after changing the optical characteristics between the first light and the second light,
A service providing method that provides a service using a composite light obtained by combining the first light and the second light. The service provision system includes an optical device;
The optical device includes a light emitting section and a predetermined optical member,
The first light and the second light emitted from the same light emitting section pass through the predetermined optical member,
A perpendicular line to the entrance surface side that is perpendicular to the entrance surface of the predetermined optical member is defined,
The traveling direction of the first light has an inclination angle with the perpendicular to the incident surface side,
The traveling direction of the second light is tilted with respect to the traveling direction of the first light, or the optical path of the second light within the predetermined optical member is made different from the optical path of the first light. , after changing the optical characteristics between the first light and the second light,
A service providing system that provides a service using composite light obtained by combining the first light and the second light.

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