JP2021148884A - Rotation angle detection device for three-dimensional object, retina projection display device, head-mounted type display device, optometric device, and input device - Google Patents

Abstract

To detect the rotation angle of a three-dimensional object having curvature within a wide range with a small number of light emitting units.SOLUTION: A rotation angle detection device for a three-dimensional object according to an aspect of the present invention comprises: light source means that includes a plurality of light emitting units; focusing and reflecting means that reflects rays of light emitted from the plurality of light emitting units toward a surface to be irradiated of the three-dimensional object having curvature and focuses the light; and light receiving position detection means that receives the reflected light reflected on the surface to be irradiated and detects the light receiving position of the reflected light. When the light receiving position detection means receives the reflected light derived from light emitted from a first light emitting unit of the plurality of light emitting units at one end of the light receiving position detection means, the light receiving position detection means receives the reflected light derived from light emitted from a second light emitting unit of the plurality of light emitting units different from the first light emitting unit at the other end of the light receiving position detection means.SELECTED DRAWING: Figure 9

Description

The present invention relates to a rotation angle detection device, a retinal projection display device, a head-mounted display device, an optometry device, and an input device for a three-dimensional object.

Development of technology for detecting the rotation angle of a three-dimensional object having a curvature such as an eyeball has progressed, and an interface for controlling electronic devices and a wearable display such as a head-mounted display are used by using the pupil position (line of sight) of the eyeball based on the rotation angle. It is expected to be applied to various applications such as support for image formation of equipment, collection of line-of-sight data of skilled engineers, and analysis of product attention.

Further, a configuration is disclosed in which the tilt position of the eyeball is detected by irradiating the eyeball with light from a light source means having a plurality of light emitting units for emitting light having directivity and detecting the light receiving position of the reflected light by the eyeball. (See, for example, Patent Document 1).

However, in the configuration of Patent Document 1, the rotation angle of the eyeball or the like may not be detected in a wide range due to the overlap of the rotation angle detection ranges for each of the plurality of light emitting units.

An object of the present invention is to detect the rotation angle of a three-dimensional object having a curvature in a wide range with a small number of light emitting parts.

The rotation angle detection device for a three-dimensional object according to one aspect of the present invention directs a light source means including a plurality of light emitting portions and light emitted from the plurality of light emitting portions toward an irradiated surface having a curvature in the three-dimensional object. The light receiving position detecting means is provided with a focusing reflecting means for reflecting and focusing, and a light receiving position detecting means for receiving the reflected light reflected by the irradiated surface of the light and detecting the light receiving position of the reflected light. Is the first of the plurality of light emitting units when the reflected light derived from the light emitted from the first light emitting unit of the plurality of light emitting units is received by one end of the light receiving position detecting means. The reflected light derived from the light emitted from the second light emitting unit different from the light emitting unit is received by the other end of the light receiving position detecting means.

According to the present invention, the rotation angle of a three-dimensional object having a curvature can be detected in a wide range by a small number of light emitting portions.

It is a figure which shows the structural example of the pupil position detection apparatus which concerns on embodiment. It is a figure which shows an example of the relationship between the rotation of an eyeball and the incident position of a laser beam to a PSD, (a) is a figure of a state in which an eyeball is not rotating, and (b) is a figure of a state in which an eyeball is rotating. be. It is a figure which shows the example of the condition which the off-axis optical system should satisfy, (a) is a figure which shows the distance between elements, (b) is a figure which shows the geometrical distance relationship represented by a coaxial optical system. It is a figure of the relationship example of the relationship between the concave mirror effective area diameter and the beam radius in the PSD light receiving surface. It is a block diagram which shows the hardware configuration example of the processing part which concerns on embodiment. It is a block diagram which shows the functional structure example of the processing part which concerns on embodiment. It is a flowchart of the processing example by the pupil position detection apparatus which concerns on embodiment. It is a figure which shows the structural example of the pupil position detection apparatus which concerns on 1st Embodiment. It is a figure of the relationship example of the rotation angle of an eyeball and the light receiving position by PSD, (a) is a figure of the light receiving position change according to the rotation angle of an eyeball, and (b) is a figure of the position in PSD. It is a figure which shows the arrangement example of a plurality of light emitting parts, (a) is a figure which shows the relationship between the anchor position and the position of a light emitting part, (b) is a figure which shows the position of each light emitting part in VCSEL. It is a figure which shows the example of the light receiving area of PSD when the eyeball rotates in a biaxial direction. It is a figure of another example of a light receiving position adjusting means, (a) is a cross-sectional view when a prism structure is used, (b) is a cross-sectional view when a diffraction structure is used, and (c) is a case where a lens array is used. The cross-sectional view of (d) is a plan view when a two-dimensional array of lens arrays is used. It is a figure explaining the reflection type condensing element including the liquid crystal reflection type condensing structure. It is a figure explaining the liquid crystal molecule light distribution state in a liquid crystal reflection type condensing structure. It is a figure explaining the light distribution state of the incident light | exit light ray by the liquid crystal reflection type condensing structure. It is a figure explaining the light guide member coupling optical system using the liquid crystal reflection type condensing structure. It is a figure which shows the structural example of the retinal projection display device which concerns on 2nd Embodiment.

Hereinafter, modes for carrying out the invention will be described with reference to the drawings. In each drawing, the same components are designated by the same reference numerals, and duplicate description will be omitted as appropriate.

As an example of the rotation angle detection device for a three-dimensional object, the pupil position detection device for the eyeball will be described in the embodiment, and the case where the pupil position detection device is mounted on the spectacle-type support will be described as an example.

In each embodiment, the eyeball of the right eye of the “human” will be described as an example, but the same applies to the eyeball of the left eye. Further, it can be applied to the eyeballs of both eyes by providing two optical devices or two retinal projection display devices.

[Embodiment]
<Configuration example of pupil position detection device 10>
FIG. 1 is a diagram illustrating an example of the configuration of the pupil position detecting device 10 according to the embodiment.

As shown in FIG. 1, the pupil position detecting device 10 includes a VCSEL (Vertical Cavity Surface Emitting LASER) 1, a concave mirror 2, a PSD (Position Sensitive Detector) 3, and a processing unit 100. Has.

The VCSEL 1, the concave mirror 2, and the PSD 3 are arranged on the optical system support 4. The optical system support 4 is rotatably fixed to the spectacle frame 22 of the spectacle-type support 20 including the spectacle lens 21 and the spectacle frame 22 via a ball joint 4a. The inclination of the optical system support 4 can be adjusted via the ball joint 4a. The spherical joint 4a constituting the installation fine adjustment mechanism includes a method of fixing by using a mechanical pressure acting between the spherical structure and its outer shell structure, and also between the magnetized spherical structure and the metal opening structure. A fixing method using a working magnetic force can be used.

The spectacle-shaped support 20 can be worn on a person's head. When the spectacle-type support 20 is attached, the optical system including the VCSEL 1, the concave mirror 2, and the PSD 3 is arranged at a position (in front of the eye) close to the eyeball 30.

VCSEL1 as an example of the "light source means" has a plurality of light emitting parts arranged two-dimensionally in a plane. Each light emitting unit emits a laser beam having directivity and a finite divergence angle. Here, the emitted laser light is an example of "light". Further, "plurality of light emitting units" is synonymous with "plurality of light emitting points" or "plurality of light emitting elements".

However, the light source means is not limited to the VCSEL as long as it can emit light. A plurality of LDs (semiconductor lasers; Laser Diodes) and LEDs (light emitting diodes; Light Emitting Diodes) that emit laser light may be arranged two-dimensionally in a plane to form a light source means. Further, a pulse laser that emits pulse laser light may be used. Further, the light source means may be configured by combining a plurality of types of light sources.

Further, the wavelength of the laser light emitted from VCSEL1 is preferably the wavelength of near-infrared light which is invisible light so as not to hinder the visibility of the "human" whose pupil position is detected. However, the present invention is not limited to this, and visible light may be used.

The laser beam L0 emitted from the VCSEL 1 directs the space in front of the eye toward the concave mirror 2 in a direction substantially parallel to the face of the person wearing the spectacle-type support 20 or the lens surface of the spectacle lens 21 worn. Propagate. Further, the laser beam L0 is divergent light that propagates while expanding the diameter of the beam due to diffraction at the ejection portion opening of VCSEL1. The divergence angle of the divergent light can be controlled by the shape of the opening of the ejection portion. The laser beam L0 propagates while diverging and is incident on the concave mirror 2.

The concave mirror 2 as an example of the focusing reflection means has a reflecting surface having a curvature, reflects the incident laser light L0, and irradiates the eyeball 30 with the focusing laser light (also referred to as focusing light) L1. The focused laser beam L1 is incident on the vicinity of the pupil 31 of the eyeball 30. The center of curvature of the concave surface of the concave mirror 2 is located off the optical axis of the optical path from VCSEL 1 to the concave mirror 2, and the optical system including VCSEL 1, the concave mirror 2, and PSD3 constitutes a so-called off-axis optical system. ing.

In the off-axis optical system according to the embodiment, the light before reaching the eyeball 30 propagates in the space in front of the eye adjacent to the eyeball 30 by folding back at least once without being reflected or scattered by the eyeball 30. , The eyeball 30 has been reached.

The angle of incidence of the focused laser beam L1 on the eyeball 30 is adjusted so that it is incident on the center of the pupil 31 of the eyeball 30 at the time of emmetropia at a predetermined angle. Further, the VCSEL 1 can emit laser light from a plurality of light emitting units, and the laser light emitted from the plurality of light emitting units is irradiated to a plurality of locations of the eyeball 30 or is irradiated to the eyeball 30 at a plurality of angles. NS.

In addition to having a plurality of light emitting units as described above, the VCSEL 1 is capable of high-speed modulation. By time-modulating the laser light irradiating the eyeball 30 and extracting a component having a modulation frequency suitable for the incident laser light from the output signal obtained by PSD3, the influence of light from the external environment (without modulation) can be affected. Can be removed. As a result, the SN ratio can be improved, which is advantageous in detecting the position of the pupil in a bright environment. It is also possible to reduce the amount of laser light that irradiates the eyeball.

The pupil surface (corneal surface) of the eyeball 30 as an example of the irradiated surface is a transparent body containing water, and generally has a reflectance of about 2 to 4%. The focused laser beam L1 incident on the vicinity of the pupil 31 of the eyeball 30 is reflected (also referred to as reflected light) on the surface of the pupil 31 of the eyeball 30, and the reflected light propagates toward PSD3. In the following, for the sake of simplicity, the surface of the eyeball 30 may be referred to as the eyeball 30, the surface of the pupil 31 may be referred to as the pupil 31, and the surface of the cornea 32 may be referred to as the cornea 32.

Here, the curvature of the reflecting surface of the concave mirror 2 is set so as to cancel the divergence of the reflected laser light due to the curvature of the eyeball 30 or the cornea 32. By doing so, it is possible to prevent the diameter of the beam of the laser beam L2 propagating toward PSD3 from widening on the light receiving surface of the PSD element.

A concave mirror is shown as an example of the focusing and reflecting means, but the present invention is not limited to this as long as it can focus (focus) light, and a configuration in which a convex lens and a flat mirror are combined or a hologram is used. A wavefront control element, a diffractive optical element, or the like may be used.

Further, if an anamorphic aspherical surface having different curvatures in two orthogonal directions in a plane intersecting the optical axis of the focused laser light L1 is used as the concave surface of the concave mirror, the diameter of the beam of the laser light L2 can be further reduced. It is suitable because the beam can be shaped into an isotropic state.

Further, the irradiated surface is not limited to the eyeball 30, and the embodiment can be applied as long as it is a three-dimensional object having a curvature. For example, the embodiment can be applied to a three-dimensional object that includes a rotating body that can rotate at the center of rotation and a curved surface that has a center of curvature, and the positions of the centers of rotation and the positions of the centers of curvature are different.

PSD3 as an example of the "light receiving position detecting means" detects the current value according to the distance to the electrode of the incident light in two orthogonal directions in the light receiving surface, and is incident from the ratio of the current values in the two orthogonal directions. It is a two-dimensional optical position detection element that calculates and outputs a detection signal indicating the position of light. The PSD3 can output a detection signal indicating the position of the beam spot formed on the light receiving surface of the PSD3.

More specifically, the PSD3 has four output terminals, a resistance film is arranged on a continuous light receiving surface (light receiving surface not divided into pixels), and electrode pairs in two orthogonal directions are provided. The photocurrent generated at the beam spot position is divided into four according to the distance from each output terminal. At this time, the electric resistance due to the resistance film acts so that the longer the distance between the beam spot position and the output terminal, the smaller the current. The PSD3 can detect an electrical signal that has passed through the resistance film via the four terminals and output a detection signal that indicates a position in the light receiving surface obtained by electrical post-processing.

Further, the PSD3 can convert the current generated by photoelectric conversion into an analog voltage signal and output it as a detection signal from four terminals. That is, the PSD3 can detect the incident position by obtaining the distance from each terminal by using the surface resistance.

By the way, when an image sensor (imaging element) is applied to the light receiving position detecting means instead of PSD3, the output result of the image sensor changes depending on the intensity of the incident light on each pixel, and the output current decreases when the intensity is low. .. In order to reduce the influence of noise light such as sunlight, it is necessary to increase the output of the light source to increase the intensity of the incident light on the image sensor. In this case, increasing the intensity of the incident light is not preferable from the viewpoint of safety to the eyeball.

Further, in the case of an image sensor, image processing for position detection is required, but a position accuracy error may occur during the processing, and the processing load also increases.

By using PSD3 as the light receiving position detecting means, the position is detected using the current division ratio (ratio) divided between the output terminals, so that the position of the incident light can be detected regardless of the intensity of the incident light. , It is preferable in that it does not require image processing.

However, the above configuration of PSD3 is an example, and other configurations may be used. Further, although an example of a two-dimensional PSD that detects a two-dimensional position in the light receiving surface is shown as PSD3, a one-dimensional PSD that detects a one-dimensional position in the light receiving surface may be used.

The processing unit 100 outputs a control signal to drive the VCSEL 1 to emit light. Further, the processing unit 100 inputs a detection signal by PSD3 and executes a process of detecting the position of the pupil 31 of the eyeball 30 as described later. The processing unit 100 can be arranged on the spectacle frame 22 or the like as an example.

Since the position of the beam spot formed on the light receiving surface of the PSD3 by the laser beam L2 changes depending on the inclination of the eyeball 30, the processing unit 100 detects the pupil position of the eyeball 30 by converting the detection signal of the PSD3 into coordinate information. can do.

The PSD3 can detect the position of the reflection point on the eyeball 30 and the direction of the normal vector, and the pupil position detection device 10 can detect the position of the detected reflection point, the normal vector, and the surface shape model of the eyeball. Based on the correspondence, the pupil position can be "estimated".

Although FIG. 1 shows an example in which the optical system and the processing unit are arranged on the spectacle frame 22, the present invention is not limited to this, and a head-mounted display, a headgear-type holding structure, or the like may be used.

<Following motion of the pupil position detection device 10 to the eye movement>
Next, the operation of following the eye movement of the pupil position detecting device 10 will be described.

Since the eyeball 30 makes eye movements such as rotation, the direction of the laser beam L2 may change due to the rotation, so that the laser beam L2 may deviate from the light receiving surface of the PSD3. On the other hand, the pupil position detecting device 10 can prevent the laser beam L2 from coming off from the light receiving surface of the PSD 3 by controlling the light emitting portion to be emitted by the VCSEL 1 to be sequentially or selectively changed.

FIG. 2 is a diagram for explaining the relationship between the rotation of the eyeball 30 and the incident position of the laser beam L2 on PSD3, and FIG. ) Is a diagram for explaining the state in which the eyeball is rotating.

FIG. 2 shows the propagation of laser light emitted from the two light emitting portions of VCSEL1. The laser beam 11 emitted from one light emitting unit is shown by a solid line, and the laser light 12 emitted from the other light emitting unit is shown by a broken line.

In FIG. 2A, the laser beam 11 reflected by the eyeball 30 is incident on the vicinity of the center of the light receiving surface of the PSD3. Therefore, the PSD 3 can detect the position of the laser beam 11 on the light receiving surface, and the pupil position detecting device 10 can detect the position of the pupil 31 based on the detection signal of the PSD 3.

On the other hand, since the laser light 12 reflected by the eyeball 30 is not incident on the light receiving surface of the PSD3, the PSD3 cannot detect the position of the laser light 12 on the light receiving surface, and the pupil position detecting device 10 is the pupil 31. The position cannot be detected.

Further, when the eyeball 30 is greatly rotated, as shown in FIG. 2B, the laser beam 11 reflected by the eyeball 30 is not incident on the light receiving surface of the PSD3. Therefore, the PSD 3 cannot detect the position of the laser beam 11 on the light receiving surface, and the pupil position detecting device 10 cannot detect the position of the pupil 31.

On the other hand, since the laser light 12 reflected by the eyeball 30 is incident near the center of the light receiving surface of the PSD3, the PSD3 can detect the position of the laser light 12 on the light receiving surface, and the pupil position detecting device. 10 can detect the position of the pupil 31 based on the detection signal of PSD3.

In this way, the pupil position of the eyeball 30 can be detected only in a limited angle range with the light from only one light emitting part, but by changing the light emitting part of VCSEL1, the light is emitted from any of the light emitting parts. The laser beam can be incident on the light receiving surface of the PSD3. As a result, even if the eyeball 30 is rotated, the state in which the laser light reflected by the eyeball 30 does not enter the light receiving surface of the PSD3 can be reduced, and the range in which the pupil position can be detected can be expanded.

In other words, the PSD3 detects the fine movement of the laser beam 12 based on the rotational movement of the eyeball 30, and the arrangement of the plurality of light emitting parts of the VCSEL1 detects the coarse movement of the laser beam 12 based on the rotational movement of the eyeball 30. In detecting the rotation angle of the 30 rotation motions, it is possible to achieve both high detection resolution and a wide detection range.

The change of the light emitting unit of the VCSEL 1 can be performed in time series by the drive signal from the processing unit 100 according to (following) the eye movement of the eyeball 30. Further, by controlling the light emitting portion according to the rotational movement of the eyeball 30, it is possible to improve the light utilization efficiency and shorten the estimation time.

However, it is not always necessary to change the light emitting portion of VCSEL1 according to the rotational movement of the eyeball. For example, the pupil position detection device 10 raster-scans (sequentially emits light) the light emitting portion of VCSEL1 at predetermined time intervals independently of the eye movement, and based on the detection signal of PSD3 in that case, the coarse movement position of the eyeball 30. May be detected.

Although only the laser light emitted from the two light emitting units is illustrated in FIG. 2 for the sake of simplicity, more light emitting parts of the VCSEL 1 can be used depending on the rotation of the eyeball 30. In this case, it is preferable to optimize the number and position of the light emitting parts of the VCSEL 1 according to the size of the light receiving surface of the PSD 3 and the size of the eyeball 30 so that the position of the pupil 31 is appropriately detected.

<Conditions for off-axis optical system>
Next, the conditions to be satisfied by the off-axis optical system including the VCSEL 1, the concave mirror 2, and the PSD 3 will be described.

In the present embodiment, the concave mirror is a condition for the laser light emitted from the VCSEL1 to be incident on the light receiving surface of the PSD3 and a condition for the focused laser light L1 to be converted into parallel light after being reflected by the corneum 32. The diameter of the effective region of 2 (the region where the laser beam can be reflected. The effective diameter) is defined.

3A and 3B are diagrams for explaining the conditions to be satisfied by the off-axis optical system, FIG. 3A is a diagram for explaining the distance between elements, and FIG. 3B is a diagram for explaining a geometrical distance relationship represented by a coaxial optical system. It is a figure.

As shown in FIG. 3A, the distance from VCSEL1 to the concave mirror 2 is d0, the distance from the concave mirror 2 to the cornea 32 is d1, and the distance from the cornea 32 to PSD3 is d2. Further, paying attention to the curvature and the effective region of the concave mirror 2, for the sake of simplicity, a coaxial optical system in which the VCSEL 1, the concave mirror 2, and the PSD 3 are arranged coaxially is assumed.

In FIG. 3B, the divergent laser light from VCSEL1 is incident on the concave mirror 2, the laser light reflected by the concave mirror 2 is focused and incident on the corneal 32, and then the laser light reflected by the corneal 32. Shows how it is incident on PSD3. Position 41 indicates the position of the light emitting portion of VCSEL 1, position 42 indicates the position of the surface of the cornea 32, and position 43 indicates the position of the surface of the concave mirror 2.

The beam radius hPSD can be calculated by the following equation (1) derived by ray tracing using the ABCD matrix.

（１）式において、ｒｃは角膜３２の曲率半径、ｈＰＳＤはＰＳＤ３の受光面でのレーザ光のビームの半径、Ｄｍは凹面ミラー２の有効領域の直径、λはＶＣＳＥＬ１の波長、ｈＵＬはＰＳＤ３の受光面でのレーザ光の、設計者が決定するビームの半径の上限値である。また、中央の式の第２項で、凹面ミラー２で反射後のレーザ光の回折によるレーザ光の広がりの効果が重畳されている。

In equation (1), rc is the radius of curvature of the cornea 32, hPSD is the radius of the laser beam on the light receiving surface of PSD3, Dm is the diameter of the effective region of the concave mirror 2, λ is the wavelength of VCSEL1, and hUL is the wavelength of PSD3. It is the upper limit of the radius of the beam determined by the designer of the laser beam on the light receiving surface. Further, in the second term of the central equation, the effect of spreading the laser light due to the diffraction of the laser light after being reflected by the concave mirror 2 is superimposed.

Based on the equation (1), the diameter Dm of the effective region of the concave mirror 2 can be determined from the equation (2).

ここで、図４は、（２）式に基づき取得された、凹面ミラー２の有効領域の直径Ｄｍと、ＰＳＤ３の受光面でのレーザ光のビームの半径ｈＰＳＤとの関係の一例を示す図である。

Here, FIG. 4 is a diagram showing an example of the relationship between the diameter Dm of the effective region of the concave mirror 2 acquired based on the equation (2) and the radius hPSD of the laser beam on the light receiving surface of the PSD3. be.

In the relationship shown in FIG. 4, the upper limit of the radius hPSD of the laser beam on the light receiving surface of PSD3 is hUL = 200um, the distance d1 from the concave mirror 2 to the cornea 32 is 24 mm, and the radius of curvature rc of the cornea 32 is 8 mm. The wavelength λ of the laser beam is 940 nm. These values are values assuming the eyeglass-type support 20, but any value may be set according to the application and the usage environment.

In FIG. 4, when the diameter Dm of the effective region of the concave mirror 2 becomes smaller, the radius hPSD of the beam on the light receiving surface of the PSD 3 is rapidly expanded due to diffraction. Further, as the diameter Dm of the effective region of the concave mirror 2 increases, the radius hPSD of the beam on the light receiving surface of the PSD 3 gradually expands. The position detection resolution of the laser beam by the PSD3 decreases as the radius hPSD of the beam increases.

As shown in FIG. 4, in order to minimize the radius hPSD of the beam on the light receiving surface of the PSD3, there is an appropriate range in the diameter Dm of the effective region of the concave mirror 2. The gray hatched area is an appropriate range, which is the range of the diameter Dm of the effective area of the concave mirror 2 satisfying the equation (2). When applied to the equation (2), the diameter Dm of the effective region of the concave mirror 2 is determined by 0.225 mm ≦ Dm ≦ 2.574 mm. By satisfying this condition, the radius hPSD of the beam on the light receiving surface of the PSD3 can be set to 200 μm or less, and the position detection resolution of the laser beam by the PSD3 can be made appropriate.

Assuming that d0 = 24√3 (mm) as a condition for the laser light to enter the eyeball 30 at an incident angle of 60 °, the laser light emitted from VCSEL1 has a divergence angle of about 7.1 ° or less in full angle. Although required, this divergence angle can be achieved by controlling the opening of the VCSEL1.

<Structure example of processing unit 100>
Next, the hardware configuration of the processing unit 100 according to the embodiment will be described. FIG. 5 is a block diagram illustrating an example of the hardware configuration of the processing unit 100.

The processing unit 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, an SSD (Solid State Drive) 104, a light source drive circuit 105, and an A / D. It has a (Analog / Digital) conversion circuit 106 and an input / output I / F (Interface) 107. Each is connected to each other by the system bus 108.

The CPU 101 reads a program or data from a storage device such as a ROM 102 or an SSD 104 onto the RAM 103 and executes processing to realize control of the entire processing unit 100 and functions described later. Note that some or all of the functions of the CPU 101 may be realized by hardware such as an ASIC (application specific integrated circuit) or an FPGA (Field-Programmable Gate Array).

The ROM 102 is a non-volatile semiconductor memory (storage device) capable of holding programs and data even when the power is turned off. The ROM 102 stores programs and data such as BIOS (Basic Input / Output System) and OS settings that are executed when the processing unit 100 is started. The RAM 103 is a volatile semiconductor memory (storage device) that temporarily holds programs and data.

The SSD 104 is a non-volatile memory in which a program for executing processing by the processing unit 100 and various data are stored. The SSD may be an HDD (Hard Disk Drive).

The light source drive circuit 105 is an electric circuit that is electrically connected to VCSEL1 and outputs a drive signal such as a drive voltage to VCSEL1 according to an input control signal. The light source drive circuit 105 can drive a plurality of light emitting units included in the VCSEL 1 at the same time or sequentially. Further, by modulating the cycle of the drive voltage, it is possible to drive the light emission in different light emission cycles.

As the drive voltage, a rectangular wave, a sine wave, or a voltage waveform having a predetermined waveform shape can be used. The light source drive circuit 105 can modulate the period of the drive voltage signal by changing the period (frequency) of the voltage waveform.

The A / D conversion circuit 106 is an electric circuit that is electrically connected to the PSD3 and outputs a digital voltage signal obtained by A / D converting an analog voltage signal output by the PSD3.

The input / output I / F 107 is an interface for connecting to an external device such as a PC (Personal Computer) or a video device.

Next, the functional configuration of the processing unit 100 will be described. FIG. 6 is a block diagram illustrating an example of the functional configuration of the processing unit 100. As shown in FIG. 6, the processing unit 100 includes a light emitting drive unit 110, a detection signal input unit 111, a calculation unit 120, and a pupil position output unit 130.

The light emitting drive unit 110 outputs a drive signal of the cycle T1 to the VCSEL 1 and drives the light emitting unit included in the VCSEL 1 to emit light in the cycle T1. The light emitting drive unit 110 can be realized by a light source drive circuit 105 or the like.

The detection signal input unit 111 is realized by the A / D conversion circuit 106 or the like, and outputs a digital voltage signal obtained by A / D conversion of the analog voltage signal input from the PSD 3 to the eyeball rotation angle estimation unit 121 included in the calculation unit 120. ..

The calculation unit 120 has an eyeball rotation angle estimation unit 121 and a pupil position acquisition unit 122, and executes a calculation process for acquiring the pupil position of the eyeball 30 based on an input signal from the detection signal input unit 111.

The eyeball rotation angle estimation unit 121 estimates the rotation angle of the eyeball 30 based on the input signal from the detection signal input unit 111, and outputs the estimated rotation angle data to the pupil position acquisition unit 122. The pupil position acquisition unit 122 executes a process of acquiring the position of the pupil 31 based on the estimated rotation angle of the eyeball 30. The acquired position data of the pupil 31 is output to an external device or the like via the pupil position output unit 130 realized by the input / output I / F 107 or the like.

<Processing by pupil position detection device 10>
Next, the processing by the pupil position detecting device 10 will be described.

Here, in the pupil position detection device 10, as a preliminary preparation for the pupil position detection, the calculation formula of the incident angle at which the laser beam irradiating the eyeball 30 by VCSEL1 is incident on the eyeball 30 and the rotation angle of the eyeball 30 is determined in advance. Therefore, first, these will be described.

The formula for calculating the rotation angle of the eyeball 30 is a formula for calculating a linear function or a quadratic function. However, the present invention is not limited to this, and any form of the formula may be used as long as the calculation formula can determine the rotation angle from the incident angle of the laser beam and the position of the PSD3 on the light receiving surface. As a simple approximation formula, the calculation formula by the quadratic function is adopted in this embodiment.

A surface shape model of the eyeball 30 can be used to determine the angle at which the laser beam is incident on the eyeball 30. For example, a short-form model eye (see, for example, "optical mechanism of the eye", precision machinery 27-11, 1961), which has long been known as a surface shape model of a general eyeball, can be used.

On the other hand, the angle of incidence of the laser beam on the eyeball 30 is determined in advance by ray tracing calculation or the like so that the incident position of the laser beam on the PSD 3 is at the center of the light receiving surface.

The position of the laser beam incident on the light receiving surface of the PSD3 should be theoretically analyzed based on the angle of incidence of the laser beam on the eyeball 30, the position of the laser beam reflected by the eyeball 30, and the inclination of the contact surface of the eyeball 30. Can be done. Then, from the solution of the theoretical analysis, it is possible to determine an inverse calculation formula (approximation formula) for estimating the rotation angle of the eyeball 30 by polynomial approximation.

The inverse calculation formula for estimating the angle of incidence of the laser beam on the eyeball 30 and the rotation angle of the eyeball 30 is stored in a memory such as ROM 102 or SSD 104 of the processing unit 100, and the light emitting unit 110 changes the light emitting unit or calculates. It is referred to in the pupil position acquisition process by the unit 120.

Next, FIG. 7 is a flowchart showing an example of processing by the pupil position detecting device 10.

First, in step S71, the light emitting drive unit 110 drives the VCSEL 1 to emit light in the light emitting cycle T1.

Subsequently, in step S72, the detection signal input unit 111 inputs the detection signal of the PSD 3 and outputs it to the eyeball rotation angle estimation unit 121 included in the calculation unit 120.

Subsequently, in step S73, the eyeball rotation angle estimation unit 121 calculates the eyeball rotation angle by substituting the input signal from the detection signal input unit 111 into the inverse calculation formula for estimating the rotation angle. Then, the calculated eyeball rotation angle data is output to the pupil position acquisition unit 122.

Subsequently, in step S74, the pupil position acquisition unit 122 acquires the pupil position using the surface shape model of the eyeball based on the input eyeball rotation angle data. The acquired pupil position data is output to an external device via the pupil position output unit 130.

In this way, the processing unit 100 can acquire the position of the pupil 31 of the eyeball 30 based on the detection signal output by the PSD3, and output the acquired position data to the external device.

<Action and effect of pupil position detection device 10>
Development of technology for detecting the position of the pupil (line of sight) has progressed, and support for image formation in wearable image display devices such as electronic device control interfaces using the line of sight, head-mounted displays or near-eye displays, and the line of sight of skilled engineers in factories, etc. It is expected to be applied to various applications such as data collection and product attention analysis (logging). In particular, a pupil position detecting device that functions as an interface between an electronic device and a person is required to have real-time performance and to reduce the size and weight of the device.

In the conventional technique, since the reflection image of the eyeball is acquired in the lighting environment and the pupil position is detected by the image processing unit based on pattern matching, the load of image processing is large, and the real-time property and the detection resolution of the pupil position are large. There was a trade-off relationship with. In addition, it is necessary to mount an image pickup device, a processor, a drive power supply, and the like, and it is difficult to reduce the size and weight of the device.

Further, as a prior art, there is disclosed a technique of detecting a time change of the reflected light intensity of a laser beam scanned at high speed on the surface of an eyeball and detecting a pupil position at high speed by a non-image method that does not use an imaging system. However, in this technique, due to reflection on the eyeball or cornea having a large curvature, the diameter of the laser beam may be widened on the light receiving surface of the photodetector, and the pupil position may not be detected properly.

In the embodiment, VCSEL 1 that emits light, a concave mirror 2 that converts light into focused light and folds the focused light toward an irradiated surface having a curvature, and reflected light of the focused light by the irradiated surface. An off-axis optical system including PSD3 that receives light and detects the position of the reflected light is arranged in front of the eye.

More specifically, the light before reaching the eyeball 30 reaches the eyeball 30 after being folded back at least once or more and propagated in the space in front of the eye adjacent to the eyeball 30 without being reflected or scattered by the eyeball 30. .. Further, the concave mirror 2 irradiates the focused laser beam toward the eyeball 30.

As a result, the curvature of the eyeball 30 or the cornea 32 can be canceled by the curvature of the focused laser light, so that the laser light reflected by the eyeball 30 or the cornea 32 can be prevented from spreading.

Further, the diameter (opening) Dm of the effective region of the concave mirror 2 is controlled by adjusting the distance d0 (see FIG. 3) from VCSEL 1 to the concave mirror 2 to change the diameter of the laser beam irradiation range for the concave mirror 2. It is possible to do. By determining the diameter (opening) Dm of the effective region of the concave mirror 2 so as to satisfy the condition of the equation (2), the diameter Dm of the effective region of the concave mirror 2 can be increased, and the laser beam is focused by the large aperture. Therefore, the diameter of the beam on the light receiving surface of the PSD3 can be reduced.

By reducing the diameter of the laser beam on the light receiving surface of the PSD3 in this way, the position detection resolution by the PSD3 and the detection accuracy of the pupil position can be ensured, and the pupil position can be appropriately detected. ..

[First Embodiment]
Next, the pupil position detecting device 10a according to the first embodiment will be described.

In the pupil position detecting device, the rotation angle may not be detected in a wide range because the detection ranges of the rotation angles are overlapped for each of the plurality of light emitting units.

In the present embodiment, when the light receiving position detecting means receives the reflected light derived from the light emitted from the first light emitting unit among the plurality of light emitting units at one end of the light receiving position detecting means, the light receiving position detecting means of the plurality of light emitting units. The other end of the light receiving position detecting means receives the reflected light derived from the light emitted from the second light emitting unit different from the first light emitting unit. This prevents the detection ranges of the rotation angles from overlapping for each of the plurality of light emitting units, and makes it possible to detect the rotation angles of a three-dimensional object having a curvature in a wide range with a small number of light emitting units.

<Configuration example of pupil position detection device 10a>
FIG. 8 is a diagram illustrating an example of the configuration of the pupil position detecting device 10a. The X direction shown in FIG. 8 indicates a horizontal direction, the Y direction indicates a vertical direction, and the Z direction indicates an emmetropic direction in a state where the eyeball is not rotated. The Z direction is a direction orthogonal to both the X direction and the Y direction, and is a direction corresponding to the front for a person wearing the spectacle-shaped support 20.

As shown in FIG. 8, the pupil position detecting device 10a includes VCSEL1a. The VCSEL1a is arranged on the + Z direction side of the PSD3 and irradiates the concave mirror 2 with the laser beam L0. Like VCSEL1, the VCSEL1a has a plurality of light emitting units ch1 to ch7 (hereinafter, when not distinguished, it is referred to as a light emitting unit ch, and not shown in FIG. 8), and each light emitting unit ch has directivity. A laser beam L0 having a finite spread angle is emitted. However, as described below, the intervals between the light emitting unit channels in the plurality of light emitting unit channels are configured to be unequal intervals.

The laser beam L0 is reflected by the concave mirror 2 and is irradiated toward the eyeball 30 as the focused laser beam L1. The laser beam L2 reflected by the eyeball 30 reaches the light receiving surface of the PSD3. The light receiving position of the laser beam L2 is detected by the PSD3. Here, the laser beam L2 corresponds to "reflected light derived from the light emitted from the light emitting unit".

Although the pupil position detecting device 10a does not include the ball joint 4a, it can be configured to include the ball joint 4a.

<Relationship between the rotation angle of the eyeball 30 and the light receiving position by PSD3>
Next, the relationship between the rotation angle of the eyeball 30 and the light receiving position of the laser beam L2 by PSD3 will be described with reference to FIG. Here, FIG. 9 is a diagram illustrating an example of the relationship between the rotation angle of the eyeball 30 and the light receiving position by PSD3, and FIG. 9A is a diagram showing a change in the light receiving position according to the rotation angle of the eyeball 30. b) is a figure explaining the position in PSD3.

The horizontal axis in FIG. 9A indicates the rotation angle θx of the eyeball 30 in the horizontal direction (X direction in FIG. 8), and the vertical axis indicates the light receiving position z in the Z direction by PSD3. Further, graphs G1 to G8 are plots of simulation results of light receiving positions by PSD3 of reflected light derived from laser light L0 emitted by each of the seven light emitting units ch1 to ch7 in VCSEL1a.

The light emitting units ch1 to ch7 are light emitting units arranged in the Z direction in VCSEL1, and the positions relative to the eyeball 30 are different for each of the light emitting units ch1 to ch7.

In FIG. 9A, the graph G1 is in the light emitting part ch1, the graph G2 is in the light emitting part ch2, the graph G3 is in the light emitting part ch3, the graph G4 is in the light emitting part ch4, the graph G5 is in the light emitting part ch5, and the graph G6 is in light emitting part. The graph G7 corresponds to the unit ch6, and the graph G7 corresponds to the light emitting unit ch7.

Further, the regions A1 to A7 represent the light receiving region of the laser beam L2 in the PSD3 corresponding to the light emitting units ch1 to ch7. In FIG. 9A, each of the areas A1 to A7 is represented by a broken line rectangle in which L-shaped figures are arranged at the four corners. The length along the horizontal axis of the graph in the regions A1 to A7 is a length corresponding to the rotation angle θx of the eyeball 30.

In FIG. 9A, the area A1 is in the light emitting part ch1, the area A2 is in the light emitting part ch2, the area A3 is in the light emitting part ch3, the area A4 is in the light emitting part ch4, the area A5 is in the light emitting part ch5, and the area A6 is light emitting. The region A7 corresponds to the unit ch6, and the region A7 corresponds to the light emitting unit ch7.

Further, the end positions C1 to C7 in FIG. 9A correspond to the rotation angle θx of the eyeball 30 when the light emitted from the light emitting portions ch1 to ch7 lands at the end position (z = -2 mm) of the PSD3. ing. Further, the end positions F1 to F7 are rotation angles θx of the eyeball 30 when the light emitted from the light emitting portions ch1 to ch7 lands at the end position (z = 2 mm) opposite to the end positions C1 to C7 of the PSD3. It corresponds to.

The length of the light receiving region of PSD3 in the Z direction is ± 2 mm. Further, in FIG. 9A, the simulation is performed by limiting the rotation of the eyeball 30 to the one-dimensional direction in the horizontal direction.

As shown in FIG. 9A, the change in the light receiving position in PSD 3 according to the rotation angle θx of the eyeball 30 is different between the minus side and the plus side of the rotation angle θx of the eyeball 30. The horizontal lengths of the regions A1 to A8 are also different. Further, as shown in graphs G1 to G7, the state of change in the light receiving position in PSD3 according to the rotation angle θx of the eyeball 30 is different for each of the light emitting units ch1 to ch7.

On the other hand, FIG. 9B shows the light receiving surface 3a of the PSD3. The light receiving surface 3a is a plane along the YZ plane. When the eyeball 30 rotates in the horizontal direction, the position of the laser beam L2 changes in the Z direction.

In FIG. 9B, the laser beam L2 ₅ is a laser beam L2 derived from the laser beam L0 emitted by the light emitting unit ch5 of the light emitting units ch1 to ch7. The laser beam L2 ₆ is a laser beam L2 from the laser light L0 emitting portion ch6 is emitted out of the light emitting portion Ch1～ch7.

In the present embodiment, when receiving the laser beam L2 ₅ at the end 3b of the PSD3 is the + Z direction side, PSD3 is to receive laser light L2 ₆ even end 3d of the -Z direction, the light emitting portion of the ch The arrangement is predetermined.

Here, receives the laser beam L2 ₅ at the end 3b, as shown in FIG. 9 (b), in a positional relationship such as heart L2 ₅ a of the laser beam L2 ₅ overlaps an end portion 3b, is PSD3 It refers to receiving the laser beam L2 _5. Similarly, the receiving the laser beam L2 ₆ at the end 3d, the central portion L2 ₆ a laser beam L2 ₆ is in a positional relationship such as to overlap with the end portion 3d, means that PSD3 to receive the laser beam L2 ₆ .. This definition is the same even when the laser beam L2 derived from another light emitting unit ch is received at the end of the PSD3.

The laser beam L2 ₅ at the ends 3b corresponding to the end position F5 in FIG. 9 (a), the laser beam L2 ₆ at the end 3d corresponds to the end position C5 in FIG. 9 (a).

Here, the light emitting unit ch5 is an example of the “first light emitting unit”, and the light emitting unit ch6 is an example of the “second light emitting unit”. However, the "first light emitting unit" may be any of the light emitting units ch1 to ch7, and the "second light emitting unit" may be any of the light emitting units ch1 to ch7. It is more preferable that the "first light emitting unit" and the "second light emitting unit" are adjacent to each other because the arrangement of the light emitting unit ch can be easily determined.

Further, the end portion 3b corresponds to "one end of the light receiving position detecting means", and the end portion 3d corresponds to "the other end of the light receiving position detecting means".

<Example of arrangement of a plurality of light emitting parts in VCSEL1a>
Next, when the PSD3 receives the laser light L2 derived from the first light emitting portion at the end portion 3b of the PSD3, the PSD3 receives the laser light L2 derived from the second light emitting portion at the end portion 3d of the PSD3. , The arrangement of the light emitting units ch1 to ch7 in VCSEL1a will be described.

10A and 10B are views for explaining an example of arrangement of a plurality of light emitting portions ch in VCSEL1a, FIG. 10A is a diagram showing a relationship between an anchor position and a position of a light emitting portion ch of VCSEL1a, and FIG. It is a figure which shows the position of a light emitting part ch.

Here, the anchor means a target for determining the position of the light emitting portion ch of the VCSEL1a. In FIG. 10, a predetermined rotation angle of the eyeball 30 is used as an anchor. The anchors θ _{x, 1 to θ x, 7} in FIG. 10A mean the rotation angle of the eyeball 30 corresponding to the end positions C1 to C7 in FIG. 9A.

“Position of light emitting part” in FIG. 10A indicates the position of the light emitting part of VCSEL1a for achieving the target corresponding to the anchor. This position is calculated by simulation and corresponds to the distance from the center (center of gravity) of VCSEL1a.

As shown in FIG. 10A, when the anchor θ _{x, 1} is -21.81 degrees, the light emitting portion ch may _{be arranged at the position ΔZ 1} , and the anchor θ _{x, 2} is -17.80 degrees. In the case of, the light emitting unit ch may be arranged _{at the position ΔZ 2.} Similarly, when the anchors θ _{x, 3 to θ x, 7} are -13.50 to +14.24 degrees, the light emitting portion ch may be arranged _{at the positions ΔZ 3 to ΔZ 7, respectively.}

In the present embodiment, the light emitting unit ch1 arranged at a position [Delta] Z _1, the light emitting unit ch2 arranged at a position [Delta] Z _2, the light emitting portion ch3 arranged at a position [Delta] Z _3, arranging the light emitting portion ch4 to the position [Delta] Z _4. Further, the light emitting unit ch ₅ is arranged at the position ΔZ _{5, the light emitting unit ch 6 is arranged at the position ΔZ 6,} and the light emitting unit ch ₇ is arranged at the position ΔZ 7.

FIG. 10B shows light emitting units ch1 to ch7 arranged in VCSEL1a so as to correspond to the _{positions ΔZ 1 to ΔZ 7.} As shown in FIG. 10B, the light emitting units ch1 to ch7 are arranged so that the distance between the adjacent light emitting units ch is different for each adjacent light emitting unit ch. In other words, the light emitting units ch1 to ch7 are arranged at non-equal intervals.

Here, the calculation method for determining the position of the light emitting unit ch of VCSEL1a will be described by taking the light emitting units ch5 and ch6 as an example.

Based on the principle of light ray tracing, it is assumed that the relationship between the light receiving position z of the laser beam L2 on the light receiving surface 3a of the PSD3 and the position Δz of the light emitting portion ch of the VCSEL1a is predetermined as Z = f (Δz; θx). The function f can be mathematically expressed based on the positional relationship between the VCSEL1a, the concave mirror 2, the PSD3, and the eyeball 30 (cornea portion) and the model of the eyeball shape.

First, in order to obtain the reference light emitting unit ch, Δz5 and θx, 5 satisfying {f (Δz5; θx, 5) = -2, f (Δz5; −θx, 5) = 2} are numerically solved. do. That is, the angle of symmetry is adjusted so that θx, 6 = −θx, 5.

Next, Δz6 and θx, 7 satisfying {f (Δz6; θx, 6) = -2, f (Δz6; θx, 7) = 2} are numerically solved in the positive direction of the rotation angle θx of the eyeball 30. do. Further, Δz4 and θx, 4 satisfying {f (Δz4; θx, 4) = -2, f (Δz4; θx, 5) = 2} in the negative direction of the rotation angle θx of the eyeball 30 are numerically set. To solve.

For Δz1 to Δz3 and θx, 1 to θx, 3, the position of the light emitting portion ch of VCSEL1a can be calculated by sequentially repeating the above calculation.

When the light emitting parts ch1 to ch7 are arranged as shown in FIG. 10B, when the PSD3 receives the laser light L2 derived from the first light emitting part at the end 3b, the PSD3 is a laser derived from the second light emitting part. The light L2 can be received at the end 3d.

As a result, the rotation angle of the eyeball 30 can be detected in a wide range with a small number of light emitting units channels without wasting the detection range of the rotation angle of the eyeball 30 by the laser beam L2.

In the above-described example, the adjacent light emitting units ch5 and ch6 have been described as examples of the first light emitting unit and the second light emitting unit, but the present invention is not limited to this, and the first light emitting unit and the second light emitting unit are adjacent to each other. It does not have to be a light emitting part.

<Example of correspondence to the rotation of the eyeball 30 in the biaxial direction>
In the above-described example, the case where the eyeball 30 rotates along the horizontal direction has been described, but the embodiment can also be applied when the eyeball 30 rotates in the biaxial direction.

FIG. 11 is a diagram illustrating an example of a light receiving region of PSD when the eyeball 30 is rotated in the biaxial direction. FIG. 11 shows a light receiving region in which the PSD3 receives the laser light L2 derived from each light emitting portion ch of the VCSEL 1a on the light receiving surface 3a with respect to the rotation of the eyeball 30 in the X and Y directions in FIG. In this case, the plurality of light emitting units ch in VCSEL1a are two-dimensionally arranged in the ΔyΔz plane (see FIG. 10B). Here, the X direction in FIG. 8 corresponds to the "predetermined direction", and the Y direction in FIG. 8 corresponds to the "intersection direction".

Similar to FIG. 9A, the broken line rectangles in which L-shaped figures are arranged at the four corners in FIG. 11 indicate the area A. The length along the horizontal axis of FIG. 11 in the region A is a length corresponding to the rotation angle of the eyeball 30 in the X direction. The length of the region A along the vertical axis of FIG. 11 is a length corresponding to the rotation angle of the eyeball 30 in the Y direction.

A plurality of laser beams L2 in VCSEL1a are cut at four corners on the light receiving surface 3a of the PSD3, and one laser light L2 is cut and shared at symmetrical positions vertically and horizontally on the four adjacent light receiving surfaces 3a. The position of the light emitting unit ch is predetermined.

<Another example of the light receiving position adjusting means for the laser beam L2>
In the above example, when the PSD3 receives the laser light L2 derived from the first light emitting portion at the end 3b, the light receiving position for the PSD3 to receive the laser light L2 derived from the second light emitting portion at the end 3d. As an adjusting means, an example in which the light emitting portions ch1 to ch7 in VCSEL1a are arranged at non-equal intervals is shown. However, the light receiving position adjusting means is not limited to adjusting the arrangement of the light emitting units ch1 to ch7.

12A and 12B are views for explaining another example of the light receiving position adjusting means for the laser beam L2, FIG. 12A is a cross-sectional view showing a configuration example when the prism structure 15a is used, and FIG. 12B is a diffraction structure 15b. (C) is a cross-sectional view showing a configuration example when a lens array 15c is used, (d) is a plan view showing a configuration example when a two-dimensional array of lens arrays 15d is used. Is.

The prism structure 15a is an optical element provided with a plurality of minute prisms. In the prism structure 15a, a plurality of prisms are arranged so as to have a one-to-one correspondence with the light emitting portion ch of the VCSEL1a. By making the inclination of the slope portion of the prism different for each prism, the propagation direction of the laser beam 1 emitted for each light emitting portion ch can be made different for each light emitting portion ch.

As a result, the function of the light receiving position adjusting means can be realized when the light emitting unit channels in the VCSEL 1a are arranged at equal intervals, and the same effect as adjusting the arrangement of the light emitting unit channels in the VCSEL 1a can be obtained.

The diffraction structure 15b is an optical element on which a fine periodic structure for diffracting the laser beam L1 is formed. By making the period of the periodic structure different for each light emitting unit ch in a one-to-one correspondence, the propagation direction of the laser beam 1 emitted for each light emitting unit ch can be made different for each light emitting unit ch.

As a result, the function of the light receiving position adjusting means can be realized when the light emitting unit channels in the VCSEL 1a are arranged at equal intervals, and the same effect as adjusting the arrangement of the light emitting unit channels in the VCSEL 1a can be obtained.

The lens array 15c is an optical element provided with a plurality of minute lenses. In the lens array 15c, a plurality of lenses are arranged so as to have a one-to-one correspondence with the light emitting portion ch of the VCSEL1a. By making the amount of eccentricity of the lens with respect to the light emitting unit ch different for each lens, the propagation direction of the laser beam 1 emitted from each light emitting unit ch can be made different for each light emitting unit ch.

As a result, the function of the light receiving position adjusting means can be realized when the light emitting unit channels in the VCSEL 1a are arranged at equal intervals, and the same effect as adjusting the arrangement of the light emitting unit channels in the VCSEL 1a can be obtained.

The prism structure 15a, the diffraction structure 15b, and the lens array 15c all correspond to deflection means for deflecting the light emitted by each of the plurality of light emitting units ch.

Further, as shown in FIG. 12D, it can be applied even when the light emitting portion ch of VCSEL1a is arranged two-dimensionally. By using the lens array 15d in which a plurality of minute lenses are arranged in the two-dimensional direction, the propagation direction of the laser beam 1 emitted from each light emitting unit ch can be made different in the two-dimensional direction for each light emitting unit ch.

Similarly, using a prism structure in which a plurality of minute prisms are arranged in the two-dimensional direction or a diffraction structure in which the period of the periodic structure is different in the two-dimensional direction, the laser beam 1 emitted for each light emitting unit ch It is also possible to make the propagation direction different for each light emitting unit ch.

<Action and effect of pupil position detection device 10a>
As described above, in the present embodiment, the PSD3 is the light emitted from the second light emitting unit when the laser beam L2 derived from the light emitted from the first light emitting unit is received by the end portion 3b of the PSD3. The laser beam L2 derived from the above is received at the end 3d of the PSD3.

As a result, the detection range of the rotation angle of the eyeball 30 by the laser beam L2 is not wasted, so that the detection range of the rotation angle is prevented from overlapping for each of a plurality of light emitting units, and the rotation angle of the eyeball 30 having a curvature is prevented. Can be detected in a wide range with a small number of light emitting parts.

Further, in the present embodiment, when the PSD3 receives the laser light L2 derived from the first light emitting portion at the end portion 3b of the PSD3, the PSD3 receives the laser light L2 derived from the second light emitting portion at the end portion 3d of the PSD3. The function of the light receiving position adjusting means for the above is realized by arranging a plurality of light emitting unit channels in the VCSEL1a at non-equal intervals.

Since the VCSEL1a is manufactured by a semiconductor process, the spacing between the light emitting portions channels can be easily adjusted. Therefore, the function of the light receiving position adjusting means can be easily realized. Further, it is more preferable to arrange the plurality of light emitting units ch in VCSEL1a so that the intervals between the adjacent light emitting units channels are gradually different, because the intervals between the light emitting unit channels can be adjusted more easily.

Here, the fact that the intervals between the adjacent light emitting unit channels are gradually different means that the intervals between the adjacent light emitting unit channels are arranged so as to be slightly smaller, or the intervals between the adjacent light emitting unit channels are gradually different from each other. It means that it is arranged so as to be large. Specifically, the light emitting unit ch1 and the light emitting unit ch2 are arranged at an interval e1, and the light emitting unit ch2 and the light emitting unit ch3 adjacent thereto are arranged at an interval e2 slightly smaller than the interval e1, and the light emitting unit ch3 adjacent thereto is arranged. And the light emitting unit ch4 is arranged at an interval e3 slightly smaller than the interval e2. Alternatively, the interval e2 may be slightly larger than the interval e1 and the interval e2 may be slightly larger than the interval e1.

Further, the above-mentioned light receiving position adjusting means is not limited to adjusting the arrangement of the light emitting units ch1 to ch7 in the VCSEL1a. The effect of the light receiving position adjusting means can also be obtained by the deflecting means for deflecting the light emitted by each of the plurality of light emitting units ch. Examples of such a light receiving position adjusting means include a prism structure 15a, a diffraction structure 15b, and a lens array 15c.

Further, when a plurality of light emitting units channels are arranged in two dimensions, the PSD3 receives the laser beam L2 derived from the first light emitting unit at either one end of the PSD3 in the X direction or one end of the PSD3 in the Y direction. The laser beam L2 derived from the second light emitting unit arranged away from the first light emitting unit in the X direction is received by the other end of the PSD3 in the X direction, and is arranged away from the first light emitting unit in the Y direction. The laser beam L2 derived from the third light emitting unit can also be received at the other end of the PSD3 in the Y direction.

With this configuration, it is possible to detect the rotation angle and the pupil position of the curved eyeball 30 in the biaxial direction in a wide range.

Further, in the present embodiment, an example of the pupil position detecting device 10a that detects the rotation angle of the eyeball 30 and detects the pupil position of the eyeball 30 based on the rotation angle is shown, but the present invention is not limited thereto.

The rotation angle detection device for a three-dimensional object according to the embodiment is, for example, a three-dimensional object including a rotating body that can rotate at the center of rotation and a curved surface that has a center of curvature, and the position and curvature of the center of rotation. It is possible to detect the rotation angle of a three-dimensional object in a wide range even in a three-dimensional object having a different center position.

Hereinafter, a modified example of the pupil position detecting device according to the embodiment will be described.

(First modification)
The pupil position detecting device according to this modification includes a first reflective condensing element 200 having a liquid crystal portion 202 in which an anisotropic molecular material is sealed, instead of the concave mirror 2. Here, the anisotropic molecular material refers to a liquid crystal material or the like.

FIG. 13 is a diagram illustrating an example of a configuration of an off-axis optical system using the first reflection type condensing element 200. As shown in FIG. 13, the first reflection type condensing element 200 includes a support substrate 201, a liquid crystal unit 202, and a 1/4 wavelength shift unit 203. Here, the first reflection type condensing element 200 is an example of the "focusing and reflecting means", and the liquid crystal unit 202 is an example of the "encapsulating part".

The linearly polarized light emitted from VCSEL1 is converted into circularly polarized light by the 1/4 wavelength shift unit 203 and incident on the liquid crystal unit 202. The light reflected by the liquid crystal unit 202 toward the eyeball 30 passes through the 1/4 wavelength shift unit 203 in the opposite direction to the forward direction, is converted into linearly polarized light again, and is incident on the corneal surface of the eyeball 30. After that, the light reflected on the surface of the cornea enters the PSD3.

Further, as shown in FIG. 14, the liquid crystal unit 202 includes a support substrate 2021, an alignment film 2022, an alignment film 2023, and a transmission support substrate 2024 that transmits light.

The liquid crystal molecule 2025 is contained in the space inside the film formed by the alignment film 2022 and the alignment film 2023. The liquid crystal molecules 2025 are spirally swirled and arranged in a direction perpendicular to the planes of the alignment films 2022 and 2023.

The orientation of the liquid crystal molecules 2025 is spatially controlled by the alignment films 2022 and 2023. Specifically, the in-planes of the alignment films 2022 and 2023 are divided into minute spatial regions, and each region is irradiated with UV light polarized in a specific direction to perform photoalignment. The orientation of the liquid crystal molecules 2025 in each minute space region is controlled.

In other words, the liquid crystal molecules 2025 are oriented so as to form a three-dimensional quasi-periodic structure inside the liquid crystal portion 202. Here, the quasi-periodic structure refers to a structure in which the structural period or its phase is spatially adjusted so as to exhibit light-collecting characteristics.

From right to left in FIG. 14, the light incident on the liquid crystal portion 202 passes through the transmission support substrate 2024 and the alignment film 2023, is reflected by the action of the liquid crystal molecules 2025, and is reflected by the action of the liquid crystal molecules 2025, and is reflected by the alignment film 2023 and the transmission support substrate 2024. Passes in the opposite direction to the forward direction, and exits from the liquid crystal unit 202.

In the example of FIG. 14, by adjusting the orientation direction on the plane of the alignment film 2022 or 2023 corresponding to the start position of the spiral structure by the liquid crystal molecules 2025, the equiphase plane 2026 of the curve showing the spiral structure is moved in the incident direction of light. On the other hand, it is curved in a concave shape. As a result, the liquid crystal molecules 2025 can function as a lens, and the light reflected by the action of the liquid crystal molecules 2025 and traveling to the right in the figure can be focused. Since a known technique (see, for example, Nature Photonics Vol. 10 (2016) p. 389) can be applied to the technique for causing the liquid crystal molecule to function as an optical element such as a lens, further detailed description thereof will be omitted here. In FIG. 13, 2027 shown by the alternate long and short dash line indicates the light incident on the liquid crystal unit 202, and 2028 indicated by the alternate long and short dash line indicates the light reflected and condensed by the liquid crystal unit 202.

Next, with reference to FIG. 15, the optical characteristics of the liquid crystal unit 202 will be further described. 15 (a) and 15 (b) show a liquid crystal display unit 202 that collects light of clockwise circularly polarized light. The liquid crystal unit 202 has different reflection or transmission characteristics for right-handed polarized light and left-handed polarized light, depending on the rotation direction of the liquid crystal molecule 2025.

In FIG. 15A, light converted into circularly polarized light by the 1/4 wavelength shift unit 203 is incident on the liquid crystal unit 202. The light reflected by the liquid crystal unit 202 is returned to linearly polarized light by passing through the 1/4 wave plate in the opposite direction to the forward direction, and is irradiated to the eyeball 30. In order to reduce the invasion of the laser beam into the eyeball 30 as much as possible, the linearly polarized light is preferably S-polarized light having an electric field vibration surface in the direction perpendicular to the paper surface.

On the other hand, FIG. 15B shows an example in the case where the light beam from VCSEL1 is randomly polarized light whose polarization is not controlled. Of the random polarized light incident on the liquid crystal unit 202, only the clockwise circularly polarized light is reflected by the support substrate 2021 and condensed, passes through the 1/4 wavelength shift unit 203, and is converted into linearly polarized light. On the other hand, the counterclockwise polarized light component passes through the support substrate 201 as it is and does not irradiate the corneal surface.

In the pupil position detection device according to this modification, the three-dimensional orientation distribution of the liquid crystal molecule 2025 can be controlled by the two-dimensional orientation control of the alignment films 2022 and 2023, whereby the reflection and diffraction efficiency are high and the thickness is thin. The first reflective condensing element 200 of the above can be provided. Further, it is possible to impart polarization selectivity to the first reflection type condensing element 200, and it is possible to provide a pupil position detecting device that achieves both reduction in the number of optical components and ensuring eye safety with respect to laser light.

(Second modification)
The pupil position detecting device according to this modification includes a second reflective condensing element 210 containing an anisotropic molecular material.

FIG. 16 is a diagram illustrating an example of a configuration of an off-axis optical system using the second reflection type condensing element 210. As shown in FIG. 16, the second reflection type condensing element 210 includes a liquid crystal unit 211, a light guide means 212, and a 1/4 wavelength shift unit 213. Here, the second reflective condensing element 210 is an example of the "focusing and reflecting means", and the liquid crystal unit 211 is an example of the "anisotropic molecular material unit".

The liquid crystal unit 211 is provided so as to come into contact with the light guide region interface of the light guide means 212. Inside the liquid crystal unit 211, similar to the liquid crystal unit 202 described above, the liquid crystal molecules are oriented so as to form a three-dimensional quasi-periodic structure inside the liquid crystal unit 211.

The light emitted from the VCSEL 1 is coupled into the light guide means 212 via the slope of the incident end of the light guide means 212. Although the light guide means 212 may be coupled to the light guide means 212 via a grating, it is preferable that the mounting substrate surface of the VCSEL 1 and the light guide means 212 are arranged orthogonally with each other in consideration of ease of mounting and accuracy. ..

The light coupled in the light guide means 212 repeats total internal reflection at the interface of the light guide means 212, and propagates inside the light guide means 212 to the vicinity of the front of the eye. Of the light internally propagating through the light guide means 212, right-handed circularly polarized light or left-handed circularly polarized light is selectively reflected by the liquid crystal unit 211, condensed by the lens function of the liquid crystal unit 211, and has a 1/4 wavelength. After being converted into linearly polarized light (S-polarized light) by the shift unit 213, the surface of the lens of the eyeball 30 is irradiated.

When the light guide means 212 is used, it is difficult to irradiate the corneal surface with light at a shallow angle. Therefore, the liquid crystal unit 211 reflects the light in the vicinity of the front surface of the eyeball 30. In this case, in order to make the light incident on the PSD3, it is necessary to collect the light at a position (specular reflection position) shifted toward the PSD3 side from the center position of the pupil on the cornea.

In the pupil position detecting device according to this modification, the light emitted from the VCSEL 1 can be irradiated to the corneal surface after securing the optical path length in the light guide means 212, so that the device can be miniaturized. Further, the VCSEL 1, the light guide means 212, the PSD 3 and the like can be integrally configured.

[Second Embodiment]
Next, the retinal projection display device according to the second embodiment will be described with reference to FIG.

FIG. 17 is a diagram illustrating an example of the configuration of the retinal projection display device according to the present embodiment.

The retinal projection display device 60 includes an RGB (Red, Green, Blue) laser light source 61, a scanning mirror 62, a plane mirror 63, a half mirror 64, an image generation unit 65, and a pupil position detection device 10a. There is.

The RGB laser light source 61 temporally modulates and outputs the RGB three-color laser light. The scanning mirror 62 two-dimensionally scans the light from the RGB laser light source 61. The scanning mirror 62 is a MEMS mirror or the like. However, the present invention is not limited to this, and any polygon mirror, galvano mirror, or the like having a reflecting portion for scanning light may be used. The MEMS mirror is advantageous in terms of miniaturization and weight reduction. The drive method of the MEMS mirror may be any of electrostatic type, piezoelectric type, electromagnetic type and the like.

The flat mirror 63 reflects the scanning light from the scanning mirror 62 toward the half mirror 64. The half mirror 64 transmits a part of the incident light and reflects a part toward the eyeball 30. The half mirror 64 has a concave curved surface shape, and focuses the reflected light in the vicinity of the pupil 31 of the eyeball 30 to form an image at the position of the retina 33. As a result, the image formed by the scanning light is projected onto the retina 33. The light 61a shown by the broken line in the figure represents the light forming an image on the retina 33. The half mirror 64 does not necessarily have to have a one-to-one ratio of reflected light and transmitted light.

The pupil position detection device 10a detects the position of the pupil 31 according to the eye movement, and transmits a feedback signal of the position of the pupil 31 to the image generation unit 65.

The image generation unit 65 has a runout control function of the scanning mirror 62 and a light emission control function of the RGB laser light source 61. Further, the image generation unit 65 receives a feedback signal of the position of the pupil 31 from the pupil position detection device 10a. The deflection angle of the scanning mirror 62 and the light emission of the RGB laser light source 61 are controlled according to the position of the pupil 31 detected by the pupil position detecting device 10a, and the projection angle of the image or the image content is rewritten. As a result, an image that follows (eye tracking) the change in the position of the pupil 31 due to the eye movement can be formed on the retina 33.

In the above-described example, the case where the retinal projection display device 60 is a wearable terminal, a head-mounted display (HMD), is shown, but the present invention is not limited to this. The retinal projection display device 60 as a head-mounted display is not only directly attached to the "human" head, but is also indirectly attached to the "human" head via a member such as a fixed portion (head). It may be a wearable display device). Further, a binocular retinal projection display device provided with a pair of retinal projection display devices 60 for the left and right eyes may be used.

[Comparison example]
Here, the apparatus described in US2016 / 0166146 according to the comparative example is compared with the pupil position detecting apparatus 10a according to the embodiment.

In the apparatus according to the comparative example, a laser light source is used, the laser light is scanned by the MEMS mirror, and the angle of incidence of the light on the eyeball is changed. On the other hand, in the embodiment, a VCSEL having a plurality of light emitting parts is used as a light source, and the angle of incidence of light on the eyeball is changed by changing the light emitting part of the VCSEL. In the embodiment, the angle of incidence of light on the eyeball is changed in this way without using a movable portion. Therefore, it is more resistant to vibration, external impact, etc., as compared with a configuration having a movable portion.

In the apparatus according to the comparative example, the reflected light intensity of the light irradiating the cornea is detected by a photodetector, whereas in the embodiment, PSD is used and the position of the light reflected by the eyeball and incident on the light receiving surface of the PSD. Is detected. Since PSD detects the position of incident light independently of the light intensity, even if there is a difference in the amount of reflected light due to the position of reflection of light in the eyeball, it is high without being affected by the difference in the amount of reflected light. Sensitivity position detection is possible. As a result, the tilted position of the eyeball such as the pupil can be detected with high accuracy.

In the embodiment, the light emitting drive unit 110 is provided, and the light emitting drive unit 110 shifts the position of the light emitting unit of the VCSEL and the light emitting timing between the light emitting units to individually light the light. As a result, it is possible to capture the coarse movement of the eyeball movement so that the reflected light from the eyeball is contained in the light receiving surface of the PSD, and to capture the fine movement of the eyeball movement by the position detection by the PSD.

In the apparatus according to the comparative example, the eyeball position is estimated from two peak intensities (two points of reflection positions on the cornea) on the time axis of the reflected light in the eyeball. In the embodiment, the eyeball position is estimated from the reflection position of one point on the eyeball such as the cornea. Therefore, the VCSEL and PSD do not necessarily have to be in symmetrical positions. In the embodiment, the PSD may not be placed near the normal reflection (specular reflection) angle of the eyeball, but may be placed on the same side as the VCSEL.

Although examples of embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and various aspects are described within the scope of the gist of the present invention described in the claims. It can be transformed and changed.

Further, the information on the pupil position detected by the pupil position detecting device 10a can also be used for eye tracking in the input device of the electronic device. For example, there is a case where the output of the pupil position detecting device 10a shown in FIG. 1 is used for eye tracking as input information to an electronic device. In other words, an input device including the pupil position detecting device 10a can be configured. This makes it possible to realize robust electronic device input such as head position deviation.

It can also be used in an optometry device that has the function of detecting the inclination of the eyeball and the position of the pupil (cornea). The optometry device refers to a device capable of performing various tests such as a visual acuity test, an optical power test, an intraocular pressure test, and an axial length test. The optometry device is a device that can perform an examination without contacting the eyeball, and has a support portion that supports the subject's face, an optometry window, and a display that makes the direction of the subject's eyeball (the direction of the line of sight) constant during the optometry. It has a display unit, a control unit, and a measurement unit. In order to improve the measurement accuracy of the measuring unit, it is required to look at one point without moving the eyeball (line of sight), and the subject fixes his face on the support part and stares at the display object displayed on the display unit through the optometry window. .. At this time, when detecting the tilt position of the eyeball, the tilt position detection device of the eyeball of the present embodiment can be used. The tilt position detection device for the eyeball is arranged on the side of the measurement unit so as not to interfere with the measurement. The tilt position (line of sight) information of the eyeball obtained by the tilt position detection device of the eyeball can be fed back to the control unit, and measurement can be performed according to the tilt position information of the eyeball.

1a VCSEL (an example of light source means)
2 Concave mirror (an example of focusing reflection means)
3 PSD (Example of light receiving position detecting means)
3a Light receiving surface 3b end (an example of one end)
3d end (an example of the other end)
10a Pupil position detection device (an example of rotation angle detection device for a three-dimensional object)
15a Prism structure (an example of deflection means)
15b Diffraction structure (an example of deflection means)
15c lens array (an example of deflection means)
20 Eyeglass-type support 21 Eyeglass lens 22 Eyeglass frame 30 Eyeball (an example of an irradiated surface, an example of a three-dimensional object)
31 Pupil 32 Cornea 33 Retina 60 Retina projection display device 61 RGB Laser light source 62 Scanning mirror 63 Plane mirror 64 Half mirror 65 Image generation unit 100 Processing unit 101 CPU
102 ROM
103 RAM
104 SSD
105 Light source drive circuit 106 A / D conversion circuit 107 Input / output I / F
110 Light emission drive unit 111 Detection signal input unit 120 Calculation unit 121 Eyeball rotation angle estimation unit 122 Pupil position acquisition unit 130 Pupil position output unit ch Light emission unit X direction Horizontal direction (example of predetermined direction)
Y direction Vertical direction (example of crossing direction)
Z direction Emmetropic direction θx, θy rotation angle d distance when the eyeball is not rotating (an example of a predetermined distance)

JP-A-2019-154815

Claims (14)

A light source means having a plurality of light emitting units and
Focusing and reflecting means for reflecting and focusing the light emitted from the plurality of light emitting units toward an irradiated surface having a curvature in a three-dimensional object.
A light receiving position detecting means for receiving the reflected light reflected by the irradiated surface of the light and detecting the light receiving position of the reflected light is provided.
When the light receiving position detecting means receives the reflected light derived from the light emitted from the first light emitting unit among the plurality of light emitting units at one end of the light receiving position detecting means, the light receiving position detecting means of the plurality of light emitting units. A rotation angle detection device for a three-dimensional object that receives the reflected light derived from light emitted from a second light emitting unit different from the first light emitting unit at the other end of the light receiving position detecting means. The rotation angle detecting device for a three-dimensional object according to claim 1, wherein the first light emitting unit and the second light emitting unit are adjacent to each other. The rotation angle detecting device for a three-dimensional object according to claim 1 or 2, wherein the plurality of light emitting units are arranged at non-equal intervals. The rotation angle detecting device for a three-dimensional object according to claim 3, wherein the plurality of light emitting units are arranged so that the distance between adjacent light emitting units is gradually different. The rotation angle detecting device for a three-dimensional object according to any one of claims 1 to 4, further comprising a deflecting means for deflecting the light emitted by each of the plurality of light emitting units. The plurality of light emitting units are arranged two-dimensionally.
The light receiving position detecting means is
One end of the light receiving position detecting means in a predetermined direction or one end of the light receiving position detecting means in an intersecting direction intersecting the predetermined direction with respect to the reflected light derived from the light emitted from the first light emitting unit. When receiving light with
A claim that the reflected light derived from the light emitted from the second light emitting unit arranged away from the first light emitting unit in the predetermined direction is received by the other end of the light receiving position detecting means in the predetermined direction. The rotation angle detecting device for a three-dimensional object according to any one of 1 to 5. 6. Claim 6 in which the reflected light derived from the light emitted from the third light emitting unit arranged away from the first light emitting unit in the intersecting direction is received by the other end of the light receiving position detecting means in the intersecting direction. A device for detecting the rotation angle of a three-dimensional object according to the above. The rotation angle detecting device for a three-dimensional object according to any one of claims 1 to 7, wherein the light source means is a vertical resonator surface emitting laser. The three-dimensional object is composed of a rotating body that can rotate at the center of rotation and a curved body that has a center of curvature.
The rotation angle detecting device for a three-dimensional object according to any one of claims 1 to 8, wherein the position of the center of rotation and the position of the center of curvature are different. The rotation angle detecting device for a three-dimensional object according to claim 9, wherein the three-dimensional object is an eyeball. A retinal projection display device having the rotation angle detecting device for a three-dimensional object according to any one of claims 1 to 10. A head-mounted display device having the rotation angle detecting device for a three-dimensional object according to any one of claims 1 to 10. An optometry device having a rotation angle detecting device for a three-dimensional object according to any one of claims 1 to 10. An input device having a rotation angle detecting device for a three-dimensional object according to any one of claims 1 to 10.

Images