JP2018171168A - Oct apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an OCT apparatus capable of acquiring wide-angle OCT data in excellent signal strength.SOLUTION: In an OCT apparatus, an OCT optical system guides a measurement light to a wide-angle region including a fundus central part and a fundus peripheral part with respect to one transverse direction that the measurement light crosses the fundus, and includes a first reference optical path having an optical path length set for acquiring OCT data including the fundus central part, and a second reference optical path having an optical path length set for acquiring OCT data including the fundus peripheral part, which is different from the first reference optical path. An image processor acquires OCT data including the fundus central part based on an interference signal of the measurement light guided to the fundus central part and a reference light from the first reference optical path, and acquires OCT data including the fundus peripheral part based on an interference signal of the measurement light guided to the fundus peripheral part and a reference light from the second reference optical path.SELECTED DRAWING: Figure 16

Description

  The present disclosure relates to an OCT apparatus that obtains OCT data of a fundus of a subject's eye.

  As an OCT apparatus that obtains OCT data of a test object, for example, an apparatus capable of acquiring OCT data by processing a spectrum interference signal output from an OCT optical system is known. A configuration for obtaining a wide-angle tomographic image by scanning a wide area is disclosed (for example, see Patent Document 1).

  For example, in the apparatus of Patent Document 1, the optical path length difference of a k-clock interferometer provided separately from the OCT interferometer is set to 22 mm or more, and one scan is performed over a wide range of the fundus.

JP 2006-209529 A

  However, in the case of the above configuration, it is essential to provide a k-clock interferometer. Since the k clock requires high speed sampling, the detector must also be high speed. However, this is not only expensive, but high frequencies are generally vulnerable to noise, and fast k clocks tend to lose their stability. For this reason, in a high frequency region, that is, at a depth away from the zero delay position, a sampling error due to a decrease in SNR or jitter is likely to occur. In addition, if the detection is to be performed stably up to a high frequency, the apparatus becomes more complicated and very expensive.

  In view of the above problems, it is an object of the present invention to provide an OCT apparatus that can acquire wide-angle OCT data with good signal strength.

  In order to solve the above problems, the present disclosure is characterized by having the following configuration.

An OCT optical system that divides light from the OCT light source into a measurement optical path and a reference optical path, and detects an interference signal between the measurement light guided to the fundus of the eye to be examined via the measurement optical path and the reference light from the reference optical path by a detector; An OCT apparatus comprising: an image processor capable of processing a spectral interference signal output from the OCT optical system and acquiring OCT data;
The OCT optical system is
An OCT optical system that guides measurement light to a wide-angle region including a fundus center and a fundus periphery in one transverse direction in which the measurement light crosses over the fundus;
A first reference optical path having an optical path length set to obtain OCT data including the fundus center, and an optical path length set to obtain OCT data including the fundus periphery. A second reference optical path different from the reference optical path,
The image processor is
Based on an interference signal between the measurement light guided to the fundus center and the reference light from the first reference optical path, OCT data including the fundus center is obtained, and the OCT data guided to the fundus periphery is obtained. OCT data including the fundus periphery is obtained based on an interference signal between measurement light and reference light from the second reference light path.

  Wide-angle OCT data can be acquired with good signal strength.

  An example of an embodiment of the present disclosure will be described based on the drawings. FIGS. 1-22 is a figure which concerns on the Example of this embodiment. In addition, the items classified by <> below can be used independently or in association with each other.

  The OCT apparatus according to this embodiment may include an OCT optical system, and may be able to acquire OCT data by processing a spectrum interference signal output from a detector of the OCT optical system. In this case, the OCT optical system may be, for example, a Fourier domain OCT optical system (SS-OCT optical system, SD-OCT optical system). The OCT optical system uses light from the OCT light source as a measurement optical path and a reference optical path. And a spectral interference signal between the measurement light guided to the test object via the measurement optical path and the reference light from the reference optical path may be detected.

  <Final fundus imaging> The OCT optical system divides light from the OCT light source into a measurement optical path and a reference optical path, and an interference signal between the measurement light guided to the fundus of the eye to be examined through the measurement optical path and the reference light from the reference optical path May be provided for detection by a detector.

  The OCT optical system may be an OCT optical system that can guide the measurement light to a wide-angle region including the fundus center and the fundus periphery in one transverse direction in which the measurement light crosses over the fundus. In this case, as the wide-angle region, for example, when the measurement light crosses on the fundus in a specific transverse direction (for example, the horizontal direction), the wide-angle region is a wide-angle region so as to cross both the fundus center and the fundus periphery. May be. In addition, with respect to the transverse region where the measurement light traverses, for example, the transverse region at the center of the fundus and the transverse region at the periphery of the fundus may be continuous in the transverse direction. The wide-angle region may be, for example, a region of 18 mm or more on the fundus. Needless to say, the wide-angle region may be used when obtaining a region narrower than 18 mm, and the apparatus of the present embodiment is particularly useful when imaging a peripheral region of the eye to be examined with a large fundus curvature.

  As the OCT optical system capable of guiding the measurement light to the wide-angle region of the fundus, for example, an objective lens optical system may be used, or an objective mirror optical system using a concave mirror may be used. Moreover, the structure by which the wide angle attachment was attached to the objective-lens optical system may be sufficient.

  As the fundus center, for example, an area including at least the macular region of the fundus and the nipple is set, and as the fundus peripheral part, an area including each region outside the both ends of the fundus center with respect to one transverse direction is set. May be. Of course, the present invention is not limited to this. For example, a region including at least the macular region of the fundus is set as the center of the fundus, and regions outside the both ends of the fundus center with respect to one transverse direction are included as the fundus periphery. An area may be set.

  The OCT optical system may include a plurality of reference light paths. For example, the OCT optical system has a first reference optical path having an optical path length set to obtain OCT data including the fundus center and an optical path length set to obtain OCT data including the fundus periphery. And a second reference optical path different from the first reference optical path. In this case, the optical path length difference between the first reference optical path and the second reference optical path may be set corresponding to the optical path length difference of the measurement light between the fundus center and the fundus periphery. In consideration of the curvature of the eyeball, for example, the optical path length of the second reference optical path may be set shorter than that of the first reference optical path.

  The OCT apparatus according to this embodiment may include an image processor, and the image processor may be able to acquire OCT data by processing a spectral interference signal output from the OCT optical system.

  In this case, for example, the image processor may obtain OCT data including the fundus center based on an interference signal between the measurement light guided to the fundus center and the reference light from the first reference light path, OCT data including the fundus periphery may be obtained based on an interference signal between the measurement light guided to the fundus periphery and the reference light from the second reference light path. In this case, for example, the OCT data including the fundus center and the OCT data including the fundus periphery may be continuous in at least one of the transverse direction and the depth direction.

  According to this, for example, by providing the reference optical path corresponding to the fundus central part and the reference optical path corresponding to the fundus peripheral part, for example, OCT data in a wide-angle region can be acquired with good signal intensity.

  Note that the image processor may synthesize OCT data including the fundus center and OCT data including the fundus periphery to obtain wide-angle OCT data of the fundus of the eye to be examined. Thereby, one piece of wide-angle OCT data can be obtained.

  The OCT optical system may include an optical scanning unit (optical scanner) for scanning the measurement light on the fundus of the eye to be examined. In this case, the optical scanning unit may scan a wide-angle region including the fundus central part and the fundus peripheral part by scanning the measurement light on the fundus in one scanning direction. In this case, for example, the scanning region in the center of the fundus and the scanning region in the periphery of the fundus may be continuous in the transverse direction. Further, the optical scanning unit may be configured to scan the measurement light up to a scanning angle at which a wide-angle region on the fundus can be scanned, for example. Further, the optical scanning unit may be arranged at a position substantially conjugate with the pupil of the eye to be measured, for example, and may measure the measurement light with the pupil center as a turning point.

  When the optical scanning unit is provided, the measurement light is scanned in a wide-angle region including the fundus central part and the fundus peripheral part by one B scan by the optical scanning part, and includes the OCT data including the fundus central part and the fundus peripheral part. OCT data may be acquired. Thereby, for example, OCT data in a wide-angle region can be acquired smoothly.

  The OCT optical system may include, for example, a first detector corresponding to the fundus center and a second detector corresponding to the fundus periphery. In this case, the OCT optical system includes a first detector for detecting an interference signal between the measurement light guided to the fundus center and the reference light from the first reference optical path, and the first detector. A second detector for detecting an interference signal between the measurement light guided to the fundus periphery and the reference light from the second reference light path, which is a different second detector, may be provided. According to this, for example, since the first detector and the second detector can be used in parallel, the OCT data of the fundus central part and the fundus peripheral part can be reliably detected, and each OCT can be detected. Data can be acquired smoothly and with good signal strength.

<The optical path length of the reference optical path>
In the first reference optical path, for example, first OCT data in a state where the choroid at the center of the fundus is formed in front of the zero delay position where the optical path lengths of the measurement light and the reference light coincide with each other is acquired. The optical path length may be set as described above. According to this, for example, in the first OCT data, mixing of a mirror image and a real image can be reduced, and the contrast on the choroid side can be improved.

  The second reference optical path is acquired, for example, by the second OCT data in a state in which the retina in the vicinity of the fundus is formed on the back side from the zero delay position where the optical path lengths of the measurement light and the reference light match. The optical path length may be set as described. According to this, for example, in the second OCT data, it is possible to reduce the mixture of the mirror image and the real image, and it is possible to reduce the influence of the light amount decrease in the fundus periphery.

  In addition, by setting the first reference optical path and the second reference optical path as described above, it is possible to reduce the mixture of the mirror image and the real image in both the first OCT data and the second OCT data, The entire OCT data in the wide angle region can be obtained with good signal strength.

  The first reference optical path and the second reference optical path are not limited to the above configuration. For example, the optical path length may be set so that the first OCT data in a state where the retina at the center of the fundus is formed on the back side with respect to the first delay optical path, For example, the optical path length of the reference optical path 2 may be set so that the second OCT data in a state where the choroid around the fundus is formed in front of the zero delay position.

  The OCT optical system may further be capable of detecting, by a detector, an interference signal between the measurement light guided to the anterior eye part to be examined via the measurement optical path and the reference light from the reference optical path. In this case, the first reference optical path and the second reference optical path are set to different optical path lengths, and one of the first reference optical path and the second reference optical path is the cornea (for example, the cornea and the lens front surface) of the eye to be examined. The optical path length for obtaining the included OCT data is set, and the other of the first reference optical path and the second reference optical path is set to the optical path length for obtaining the OCT data including the crystalline lens of the eye to be examined (for example, the posterior surface of the crystalline lens). May be. According to this, in addition to the OCT data in the wide-angle region, OCT data in a wide range of the anterior segment can be acquired with a good signal intensity.

  In the above description, two reference light paths corresponding to the fundus center and the fundus periphery are provided, but the present invention is not limited to this, and three or more reference light paths may be provided. For example, the entire fundus is divided into a fundus central part, a first fundus peripheral part outside the fundus central part, and a second fundus peripheral part outside the first fundus peripheral part. There may be provided a first reference optical path corresponding to the first part, a second reference optical path corresponding to the first fundus peripheral part, and a third reference optical path corresponding to the second fundus peripheral part.

  In addition, the first wide angle set to the first reference optical path corresponding to the fundus center and the second reference optical path corresponding to the first fundus periphery by adjusting the optical path lengths of the two reference optical paths The second wide-angle imaging mode set to the imaging mode, the first reference optical path corresponding to the fundus central part or the first fundus peripheral part, and the second reference optical path corresponding to the second fundus peripheral part And may be switchable.

<Example>
In this embodiment, an optical coherence tomography (OCT) apparatus shown in FIG. 1 is used as the OCT apparatus. The OCT apparatus according to the present embodiment has, for example, a wavelength sweep type OCT (SS-OCT: Swept Source-OCT) as a basic configuration, a wavelength variable light source 102, an interference optical system (OCT optical system) 100, an arithmetic controller ( Calculation control unit) 70. In addition, the OCT apparatus may be provided with a memory 72, a display unit 75, a front image observation system and a fixation target projection system (not shown). An arithmetic controller (hereinafter referred to as a control unit) 70 is connected to the variable wavelength light source 102, the interference optical system 100, the memory 72, and the display unit 75.

  The interference optical system 100 guides the measurement light to the eye E by the light guide optical system 150. The interference optical system 100 guides reference light to the reference optical system 110. The interference optical system 100 causes the detector (light receiving element) 120 to receive the interference signal light acquired by the interference between the measurement light reflected by the eye E and the reference light. Further, the interference optical system 100 of this embodiment includes an FPN generation optical system 200 (details will be described later). The interference optical system 100 is mounted in a housing (device main body) (not shown), and the housing is three-dimensionally moved with respect to the eye E by a known alignment moving mechanism via an operation member such as a joystick. The alignment with respect to the eye to be examined may be performed.

  For the interference optical system 100, the SS-OCT method is used, and a variable wavelength light source (wavelength scanning light source) that changes the emission wavelength at a high speed in time is used as the light source 102. The light source 102 includes, for example, a laser medium, a resonator, and a wavelength selection filter. Examples of the wavelength selection filter include a combination of a diffraction grating and a polygon mirror, and a filter using a Fabry-Perot etalon. A VCSEL wavelength tunable light source may be used as the light source 102.

  The coupler (splitter) 104 is used as a first light splitter, and splits the light emitted from the light source 102 into a measurement optical path and a reference optical path. For example, the coupler 104 guides light from the light source 102 to the optical fiber 105 on the measurement optical path side and guides it to the reference optical system 110 on the reference optical path side.

  The coupler (splitter) 130 is used as a second light splitter, and splits light (measurement light) from the optical fiber 105 into an optical path of the light guide optical system 150 and an optical path of the FPN generation optical system 200. That is, the light guide optical system 150 and the FPN generation optical system 200 are provided in the measurement optical path. The coupler (splitter) 130 may be a beam splitter or a circulator.

<Light guide optical system>
The light guide optical system 150 is provided to guide the measurement light to the eye E. In the light guide optical system 150, for example, an optical fiber 152, a coupler 153, a collimator lens 154, an optical scanner 156, and an objective lens system 158 may be sequentially provided. In this case, the measurement light is converted into a parallel beam by the collimator lens 154 via the optical fiber 152 and the coupler 153 and travels toward the optical scanner 156. The light that has passed through the optical scanner 156 is applied to the eye E via the objective lens system 158. Measurement light is applied to both the anterior eye segment and the posterior eye segment, and is scattered and reflected by each tissue.

  The optical scanner 156 may scan the measurement light on the eye E in the XY direction (transverse direction). The optical scanner 156 is, for example, two galvanometer mirrors, and the reflection angle thereof is arbitrarily adjusted by a driving mechanism. The reflection (advance) direction of the light beam emitted from the light source 102 is changed and scanned in an arbitrary direction on the fundus. As the optical scanner 156, for example, an acousto-optic device (AOM) that changes the traveling (deflection) direction of light may be used in addition to a reflecting mirror (galvano mirror, polygon mirror, resonant scanner).

  In this case, the scattered light (reflected light) from the eye E by the measurement light reaches the coupler 130 after passing through the objective lens system 158, the optical scanner 156, the collimator lens 154, the coupler 153, and the optical fiber 152. The coupler 130 causes the light from the optical fiber 152 to travel toward the first detector 120a (for example, the optical fiber 115-coupler 350a) and the optical path toward the second detector 120b (for example, the optical fiber 105-coupler 104-optical fiber). 117 to coupler 350b).

  Of the measurement light split by the coupler 130, the measurement light that has passed through the optical path toward the first detector 120a is combined with the reference light from the first reference optical path 110a and interferes with the coupler 350a. In addition, the measurement light that has passed through the optical path toward the second detector 120b is combined with the reference light from the second reference optical path 110b and interferes by the coupler 350b.

<Reference optical system>
The reference optical system 110 generates reference light that is combined with reflected light acquired by reflection of measurement light by the eye E. The reference light that has passed through the reference optical system 110 is combined with light from the measurement optical path by a coupler (for example, couplers 350a and 350b) and interferes therewith. The reference optical system 110 may be a Michelson type or a Mach-Zehnder type.

  The reference optical system 110 may be formed by, for example, a reflection optical system, and may guide the light from the coupler 104 to the detector 120 by reflecting the light from the reflection optical system. The reference optical system 110 may be formed by a transmission optical system. In this case, the reference optical system 110 guides the light from the coupler 104 to the detector 120 by transmitting the light without returning.

  An optical member for adjusting the optical path length difference between the measurement light and the reference light may be disposed in at least one of the measurement light path and the reference light path. For example, the optical path length of the measurement light may be adjusted by integrally moving the collimator lens 154 and the coupler 153, and as a result, the optical path length difference between the measurement light and the reference light may be adjusted. Of course, by moving the optical member arranged in the reference optical path, as a result, the optical path length difference between the measurement light and the reference light may be adjusted.

  In the present embodiment, a plurality of reference light paths may be provided as the reference optical system 110. For example, a first reference light path 110a and a second reference light path 110b may be provided.

  In the reference optical system 110, for example, an optical splitter (for example, a coupler 111) for dividing the reference optical path into a first reference optical path 110a and a second reference optical path 110b may be provided. For example, an optical member 112 that is moved to change the optical path length of the reference light may be provided in at least one of the first reference optical path 110a and the second reference optical path 110b. The optical member 112 may be moved by a drive unit (not shown) controlled by the control unit 70.

  For example, the reference light from the coupler 104 is divided by the coupler 111 into a first reference light path 110a and a second reference light path 110b. The reference light that has passed through the first reference light path 110a is combined with the measurement light from the optical fiber 115 and interferes by the coupler 350a. The reference light that has passed through the second reference light path 110b is combined with the measurement light from the optical fiber 117 and interferes by the coupler 350b.

  The first reference optical path 110a and the second reference optical path 110b may be set to different optical path lengths. Thereby, for example, interference signals corresponding to different depth regions can be simultaneously acquired, and as a result, a wide range of OCT data can be simultaneously acquired.

  For example, the first reference light path 110a is provided to obtain an interference signal corresponding to a first depth region (for example, the crystalline lens, the fundus) in the eye to be examined, and the second reference light path 110b is the first reference light path 110b in the eye to be examined. It may be provided to obtain an interference signal corresponding to two depth regions (eg, cornea). In this case, the second depth region is set to a region different from the first depth region. In this case, the first depth region and the second depth region may be regions that are separated from each other, may be regions that are adjacent to each other, or may be regions that partially overlap each other. Good.

  Note that the first reference optical path 110a and the second reference optical path 110b may be set to the same optical path length. Thereby, for example, interference signals corresponding to the same depth region can be simultaneously acquired, and as a result, a plurality of OCT data regarding the same region can be simultaneously acquired.

<Photodetector>
The detector 120 is provided to detect interference caused by light from the measurement optical path and light from the reference optical path. The detector 120 may be a light receiving element. For example, the detector 120 may be a point sensor having only one light receiving unit, and for example, an avalanche photodiode may be used.

  In the present embodiment, the detector 120 may be provided with a first detector 120a and a second detector 120b different from the first detector 120a. The first detector 120a may be provided as a detector for detecting a first interference signal between the reference light from the first reference light path 110a and the measurement light from the optical fiber 115. The second detector 120b may be provided as a detector for detecting a second interference signal between the reference light from the second reference light path 110b and the measurement light from the optical fiber 117. In this case, the first interference signal and the second interference are detected by detecting the first interference signal by the first detector 120a and simultaneously detecting the second interference signal by the second detector 120b. Signals can be detected simultaneously. The sampling rates of these detectors may be different from each other or the same.

  Each of the first detector 120a and the second detector 120b may be a balanced detector. In this case, each of the first detector 120a and the second detector 120b includes a plurality of light receiving elements, obtains a difference between the interference signal from the first light receiving element and the interference signal from the second light receiving element, Unnecessary noise included in the interference signal can be reduced.

<FPN generation optical system>
The FPN generation optical system 200 may be provided to generate an FPN signal. The FPN generation optical system 200 may include at least one optical member (for example, the first optical member 204 or the second optical member 206) that generates FPN. In this embodiment, the FPN generation optical system 200 is arranged at a position where the measurement light is branched from the optical path toward the eye to be examined.

  As the FPN generation optical system 200, for example, a reflection optical system may be used, and as the FPN generation optical member, for example, a light reflection member (for example, a mirror) may be used. In this embodiment, a plurality of optical members that generate FPN are provided. However, the present invention is not limited to this, and the FPN generation optical system 200 may be configured to include one optical member that generates FPN.

  The first detector 120a detects the FPN signal together with the first interference signal, and the second detector 120b detects the FPN signal together with the second interference signal. For example, the FPN signal is a combination of first OCT data based on the first interference signal and second OCT data based on the second interference signal (details will be described later), wave number mapping correction of each interference signal, It may be used for polarization adjustment or the like.

  For example, the FPN generation optical system 200 may be provided to generate a first FPN signal and a second FPN signal. For example, the FPN generation optical system 200 may include at least a first optical member 204 that generates a first FPN and a second optical member 206 that generates a second FPN. The second optical member 206 may be arranged so that the light passing through the second optical member is different from the optical path length of the light passing through the first optical member 204. Thereby, the second FPN is generated at a different position with respect to the first FPN. A zero delay position to be described later corresponds to a position where the optical path length of the measurement light and the optical path length of the reference light coincide with each other on the OCT data.

  By using the first optical member 204 and the second optical member 206 at the same time, it is possible to generate two FPN signals at the same time, so that the time required for processing the two FPN signals is increased. The effect of slack can be reduced. Note that the FPN optical system 200 may include three or more FPN generation optical members, and by using these simultaneously, it is possible to simultaneously generate three or more FPN signals.

  As the FPN generation optical system 200, for example, a reflection optical system may be used, and as the FPN generation optical member, for example, a light reflection member (for example, a mirror) may be used. In this embodiment, mirrors are used as the first FPN generating optical member 204 and the second FPN generating optical member 206, but the present invention is not limited to this.

  In this case, the light from the coupler 130 passes through the first optical member 204 or the second optical member 206 and then returns to the coupler 130, and passes through the same path as the light from the light guide optical system 150. 350a reaches the coupler 350b. The light from the FPN generation optical system 200 is combined with the reference light by the couplers 350a and 350b and interferes therewith. The optical path lengths of the light source 102 to the FPN generation optical system 200 to the couplers 350a and 350b and the optical path length from the light source 102 to the reference optical system 110 to the couplers 350a and 350b may be set to substantially the same length.

  For example, when the light passing through the first optical member 204 interferes with the reference light, an interference signal light corresponding to the first FPN is generated, and a first FPN signal is generated in the detector 120. The light passing through the second optical member 206 interferes with the reference light, whereby interference signal light corresponding to the second FPN is generated, and the detector 120 generates a second FPN signal. As a result, for example, the detector 120 detects both the first FPN signal and the second FPN signal simultaneously.

  When the FPN signal is used for predetermined processing, both the first FPN signal and the second FPN signal may be detected simultaneously in each of the detector 120a and the detector 120b, or one FPN is detected in the detector 120a. The signal may be detected and the other FPN signal may be detected at the detector 120b. In addition, one of the detector 120a and the detector 120b detects both the first FPN signal and the second FPN signal simultaneously, and the other of the detector 120a and the detector 120b detects the first FPN signal and the second FPN signal. One of the FPN signals may be detected. Further, at least one FPN signal may be detected by one of the detector 120a and the detector 120b, and the FPN signal may not be detected by the other of the detector 120a and the detector 120b.

  Note that a light amount monitor 210 may be disposed in the FPN generation optical system 200, and light from the light source 102 is detected by the light amount monitor 120 via the beam splitter 208. The output signal from the light amount monitor 120 may be used to determine whether or not the amount of light emitted from the light source 102 is appropriate.

<Light splitting ratio>
Here, the coupler 130 divides the light from the coupler 104 into the optical path of the light guide optical system 150 and the optical path of the FPN generation optical system 200, and the light from the light guide optical system 150 and the FPN generation optical system 200, It divides | segments into the optical path (for example, optical fiber 115-coupler 350a) which goes to the 1st detector 350a, and the optical path (for example, optical fiber 105-coupler 104-optical fiber 117-coupler 350b) which goes to the coupler 104. FIG.

  The light amount division ratio S <b> 1 of the coupler 130 when dividing the light from the fiber 105 may be set so that more light is guided to the FPN generation optical system 200 than to the light guide optical system 150. In this case, the light amount ratio by which the light from the fiber 105 is divided by the coupler 130- is the light guide optical system 150 <FPN generation optical system 200.

  The light quantity division ratio S2 of the coupler 130 when dividing the light from the light guide optical system 150 depends on the light quantity division ratio S1. As a result, with respect to the light from the light guide optical system 150, more light is guided to the optical path toward the second detector 120a than to the optical path toward the first detector 120a. In this case, the light amount ratio by which the light from the light guide optical system 150 is divided by the coupler 130 is such that the optical path toward the first detector 120a <the optical path toward the coupler 104.

  The measurement light that has passed through the optical path toward the first detector 120a interferes with the light from the first reference optical path 110a, and then is detected as a first interference signal by the first detector 120a. On the other hand, the measurement light traveling toward the coupler 104 is split by the coupler 104 into an optical path toward the light source 102 and an optical path toward the second detector 120b (for example, the optical fiber 117 to the coupler 350b). The light amount division ratio S4 when the light from the coupler 130 is divided depends on the light amount division ratio S3 when the light from the light source 102 is divided into the measurement optical path and the reference optical path. When the light quantity division ratio S3 is set so that more light is guided to the reference optical path than the measurement optical path, the light quantity ratio by which the light from the coupler 130 is divided by the coupler 104 is such that the optical path toward the light source 102 <second. This is an optical path toward the detector 120b. As a result, with respect to the light from the coupler 130, more light is guided to the optical path toward the second detector 120 b than to the optical path toward the light source 102. The measurement light that has passed through the optical path toward the second detector 120b interferes with the light from the second reference optical path 110b, and then is detected as a second interference signal by the second detector 120b.

  In summary, the optical path toward the first detector 120a <the optical path toward the coupler 104 with respect to the light quantity division ratio S2 of the coupler 130, and the optical path toward the light source 102 with respect to the light quantity division ratio S4 of the coupler 104 <second. It is set in the optical path toward the detector 120b.

  As a result, the first interference signal detected by the first detector 120a and the second interference signal detected by the second detector 120b can be detected with an appropriate balance. That is, in the case of an optical path directed to the second detector 120b via the coupler 104, the light from the light guide optical system 150 passes through a plurality of optical splitters (for example, the coupler 130 and the coupler 104), and thus the light amount Whereas the number of attenuations is large, in the case of the optical path toward the first detector 120a, the light from the light guide optical system 150 reaches the first detector 120a via the coupler 130, and therefore the amount of light attenuation is reduced. The number of times is relatively small.

  Therefore, regarding the light amount division ratio S2 of the coupler 130, the optical path toward the first detector 120a <the optical path toward the coupler 104, and regarding the light amount division ratio S4 of the coupler 104, the optical path toward the light source 102 <the second detector 120b. Since the light path is directed to, even if the light amount attenuation is performed a plurality of times, the light amount attenuation can be reduced, and as a result, the difference in signal intensity between the first detector 120a and the second detector 120b can be reduced. Less. Therefore, the difference in signal intensity between the OCT data obtained by the first detector 120a and the OCT data obtained by the second detector 120b is reduced, and appropriate OCT data can be acquired.

  It should be noted that the light quantity division ratio S2 of the coupler 130 and the light quantity division ratio S4 of the coupler 104 are set so that the light quantity ratio between the optical path toward the first detector 120a and the optical path toward the second detector 120b is the same. May be. As an example, regarding the light amount division ratio S2 of the coupler 130, the optical path toward the first detector 120a: the optical path toward the coupler 104 = 6: 4, and the light path toward the light source 102 regarding the light amount division ratio S4 of the coupler 102: No. The optical path toward the second detector 120b may be set to be 1: 2.

  The light amount split ratio S2 of the coupler 130 and the light amount split ratio S4 of the coupler 104 are not limited to the above, and the amount of reflected light at the imaging region of the OCT data detected by the first detector 120a and the second detector 120b is related. In consideration of the difference, the light quantity division ratio may be set. That is, the reflected light from the cornea of the eye to be examined has a large amount of reflected light, but the light from the crystalline lens and the fundus has a relatively small amount of reflected light. Therefore, in consideration of the ratio of the amount of light reflected by the imaging region, as a result, the light amount of the coupler 130 so that the signal intensity of the OCT data between the first detector 120a and the second detector 120b is the same. The division ratio S2 and the light amount division ratio S4 of the coupler 104 may be set.

  In this embodiment, when the light from the light guide optical system 150 is guided to a plurality of detectors, the light traveling toward the first detector 120a via one light splitter (for example, the coupler 130) The light divided into the light directed to the second detector 120b through a plurality of couplers (for example, the coupler 130 and the coupler 104) can more efficiently guide the light from the light guide optical system 150 to each detector. To be free. Such an optical arrangement is particularly advantageous when the amount of light emitted from the light source 120 is limited and the reflected light from the eye to be examined is weak.

  FIG. 2 is a diagram illustrating an example of an FPN generation optical system according to the present embodiment. The FPN generation optical system 200 may include at least a first optical path 203 including a first optical member 204 and a second optical path 205 including a second optical member 206, for example. Here, between the first optical path 203 and the second optical path 205, the optical path length of the first optical path 203 and the optical path length of the second optical path 205 are different. It is generated at a position different from the FPN. For example, when the optical path length of the second optical path 205 is longer than the optical path length of the first optical path 203, the optical path length is generated at a position farther from the zero delay than the first FPN.

  The FPN generation optical system 200 may include an optical path splitting member 202 (for example, a beam splitter). The optical path splitting member 202 splits the light path on the light source side into a first optical path 203 and a second optical path 205. May be provided for this purpose. The first optical member 204 is arranged in the first optical path 203 divided by the optical path dividing member 202, and the second optical member 206 is arranged in the second optical path divided by the optical path dividing member 202. ing.

  The first optical path 203 and the second optical path 205 have different optical path lengths. That is, the optical path length from the branch position of the optical path dividing member 202 to the first optical member 204 and the optical path length from the branch position of the optical path dividing member 202 to the second optical member 206 are different. As a result, the first FPN formed by the first optical member 204 and the second FPN formed by the second optical member 206 are formed at different positions in the depth direction on the OCT image. . Note that the distance between the first FPN and the second FPN in the depth direction is due to the optical path length difference between the first optical path 203 and the second optical path 205.

  Further, the first optical path 203 and the second optical path 205 are set (constructed) to have the same optical dispersion amount. As a result, mapping information of each wave number component calculated using the first FPN (hereinafter referred to as first wave number mapping information) and mapping information of each wave number component calculated using the second FPN (hereinafter referred to as “first wave number mapping information”). When calculating correction information for correcting the mapping state of each wave number component based on the difference from the second wave number mapping information), the dispersion component included in each mapping information can be canceled appropriately. The correction information can be obtained with high accuracy (details will be described later). In this case, the equal dispersion amounts do not necessarily have to be exactly the same, as long as a certain degree of accuracy is ensured and the dispersion components can be canceled appropriately.

<Polarization adjustment mechanism>
In the OCT optical system 100 of the present embodiment, a plurality of polarization adjustment units may be provided. For example, in the optical path of the OCT optical system 100, a first polarization adjustment unit 300, a second polarization adjustment unit 302, and a second polarization adjustment unit are provided. 3 polarization adjustment units 304 may be provided (see FIG. 1).

  The first polarization adjusting unit 300 may be provided in order to adjust the polarization state of the reference light that is disposed in the optical path of the first reference optical path 110a and passes through the first reference optical path 110a. The second polarization adjustment unit 302 may be provided in order to adjust the polarization state of the reference light that is disposed in the optical path of the second reference optical path 110b and passes through the second reference optical path 110b. The third polarization adjustment unit 304 may be disposed in the optical path of the FPN generation optical system 200 and may be provided to adjust the polarization state of light passing through the optical path of the FPN generation optical system 200.

<Acquisition of depth information>
When the emission wavelength is changed by the light source 102, the corresponding interference signal light is received by the detector 120, and as a result, detected by the detector 120 as a spectrum signal. The control unit 70 processes (Fourier analysis) the spectrum signal detected by the detector 120 to obtain OCT data of the eye to be examined.

  The spectrum signal (spectrum data) may be rewritten as a function of the wavelength λ and converted into a function I (k) that is equally spaced with respect to the wave number k (= 2π / λ). Alternatively, it may be acquired from the beginning as a function I (k) that is equally spaced with respect to the wave number k (K-CLOCK technique). The arithmetic controller may obtain OCT data in the depth (Z) region by performing a Fourier transform on the spectrum signal in the wave number k space.

  Furthermore, the information after the Fourier transform may be expressed as a signal including a real component and an imaginary component in the Z space. The control unit 70 may obtain OCT data by obtaining absolute values of real and imaginary components in the signal in the Z space.

  In the present embodiment, the control unit 70 processes the first interference signal detected by the first detector 120a to obtain first OCT data, and the second detector 120b detects the second signal detected by the second detector 120b. The second OCT data may be obtained by processing the interference signal. Here, when the first reference optical path 110a and the second reference optical path 120b are set to different optical path lengths, the first OCT data and the second OCT data are at least partially different in the depth direction. When the first reference optical path 110a and the second reference optical path 120b are set to the same optical path length, the first OCT data and the second OCT data are the same region in the depth direction. OCT data is acquired.

<Control system>
The control unit 70 may include a CPU (processor), a RAM, a ROM, and the like (see FIG. 1). For example, the CPU of the control unit 70 may control the OCT apparatus. The RAM temporarily stores various information. Various programs for controlling the operation of the OCT apparatus, initial values, and the like may be stored in the ROM of the control unit 70.

  A non-volatile memory (hereinafter abbreviated as “memory”) 72 as a storage unit, a display unit 75, and the like may be electrically connected to the control unit 70. The memory 72 may be a non-transitory storage medium that can retain stored contents even when power supply is interrupted. For example, a hard disk drive, a flash ROM, and a USB memory that is detachably attached to the OCT apparatus can be used as the memory 72. The memory 72 may store a control program for controlling acquisition of OCT data and imaging of an OCT image, an arithmetic processing program for synthesizing an OCT image using FPN, and a mapping state of each wave number component An arithmetic processing program for obtaining correction information for correcting the above may be stored. In addition to the OCT image generated from the OCT data, the memory 72 may store various types of information related to imaging. The display unit 75 may display an OCT image generated from the OCT data.

<Image composition using FPN>
The control unit 70 converts the first OCT data based on the first interference signal and the second OCT data based on the second interference signal into the FPN signal detected by the first detector 120a and the second OCT data. The synthesized OCT data may be obtained by synthesis based on the FPN signal detected by the detector 120b (see FIGS. 3 to 5). That is, the FPN signal may be used as a reference signal for combining a plurality of OCT data. Here, the second OCT data may be different from the first OCT data in at least a part of the depth region on the eye to be examined.

  As an example, since the arrangement position of the optical member (for example, the optical members 204 and 206) for generating the FPN in the FPN generation optical system 200 is known, the positional relationship between the first OCT data and the second OCT data is determined. You may set using a FPN signal.

  Thereby, the positional relationship between the first OCT data and the second OCT data can be set appropriately. In the present embodiment, the first OCT data is detected by the first detector 120a and the second OCT data is detected by the second detector 120b at the same time. Positional misalignment due to such as can be reduced.

  For example, the FPN generation optical system 200 generates a first FPN that generates a first FPN (for example, the first optical member 204) and a second FPN that generates a second FPN at a position different from the first FPN. And an FPN generation optical system for generating at least two FPN signals, at least two optical members (for example, the second optical member 206).

  The control unit 70 uses the first optical member detected by the first detector 120a to generate the first OCT data based on the first interference signal and the second OCT data based on the second interference signal. The synthesized OCT data may be obtained by synthesis based on the FPN and the FPN by the second optical member detected by the second detector 120b.

  FIGS. 3 and 4 are diagrams showing an example of data when a plurality of OCT data is synthesized using an FPN signal. FIG. 3 is a diagram before synthesis, and FIG. 4 is an image diagram after synthesis. FPN1 is an FPN signal generated by the first optical member 204, and FPN2 is an FPN signal generated by the second optical member 206.

In FIG. 3, FPN1 is formed in the first OCT data, and FPN2 is formed in the second OCT data. The first OCT data is acquired using the first reference optical path 110a and the first detector 110a, and the second OCT data is acquired using the second reference optical path 110b and the second detector 110b. May be.

  When setting the positional relationship between the OCT data using the FPN signal, the control unit 70 uses, for example, the position between the OCT data using FPN1 included in the first OCT data and FPN2 included in the second OCT data. A relationship may be set. Here, the control unit 70 may detect the position of the FPN in the depth direction and synthesize a plurality of OCT data based on the detected position of the FPN (see FIG. 4).

  Here, since the positional relationship between the first optical member 204 and the second optical member 204 is known (for example, the optical path length ΔD), the control unit 70 performs the first OCT data and the second OCT data. When combining data, the positions of FPN1 and FPN2 may be detected and combined so that the detection position of FPN1 and the detection position of FPN2 are separated by the optical path length ΔD. It should be noted that any one of the OCT data may be used for the synthesis of the overlapping portion between the plurality of OCT data, or the average of both OCT data may be obtained.

  The control unit 70 may measure the dimensions of the eye to be examined (for example, anterior chamber depth, axial length, etc.) based on the synthesized OCT data synthesized as described above, and further, the obtained measurement results are displayed. You may display on the display part 75. FIG.

  FIG. 5 is a diagram showing an example of data transformation when combining a plurality of OCT data using the FPN signal. FPN1 and FPN2 are formed in the third OCT data. Here, the third OCT data may be acquired using the first reference optical path 110a and the first detector 110a, and the third OCT data is adjusted by adjusting the optical path length of the first reference optical path 110a. OCT data may be acquired.

  Here, the control unit 70 may set the positional relationship between the first OCT data and the second OCT data using the third OCT data. In this case, for example, the control unit 70 determines the positional relationship so that the detection position of FPN1 on the first OCT data and the detection position of FPN1 on the third OCT data are the same position in the depth direction. Further, for example, the control unit 70 may detect the FPN2 detection position on the second OCT data and the FPN2 detection position on the third OCT data at the same position in the depth direction. The positional relationship may be set so that According to this, even if the position of the optical member for generating FPN fluctuates due to secular change, the actual positional relationship can be used, so that the positional relationship between the first OCT data and the second OCT data can be further increased. It can be set stably.

  When detecting the position of the FPN in the depth direction, for example, the control unit 70 processes the OCT data acquired by the detectors 120a and 120b, and generates an optical member for generating FPN (for example, the first optical unit). The FPN signal from the member 204 or the second optical member 206) may be extracted. Since the signal strength of the FPN signal is known, the control unit 70 determines whether or not the luminance signal of the OCT data exceeds a threshold set for obtaining the FPN signal, for example, for generating the FPN. FPN signals (reference signals) corresponding to the optical members can be extracted. Note that FPN1 and FPN2 can be determined using a known arrangement.

  Note that the present invention is not limited to the above-described method, and the third OCT data in FIG. 5 may be used as the first OCT data and may be combined as the second OCT data in FIG. 5 (see FIG. 6). In this case, FPN1 and FPN2 are formed in the first OCT data, and FPN2 is formed in the second OCT data. The first OCT data is acquired using the first reference optical path 110a and the first detector 110a, and the second OCT data is acquired using the second reference optical path 110b and the second detector 110b. May be.

  In this case, the control unit 70 may detect the position of the FPN 2 and set the positional relationship between the OCT data using the detected position, or the FPN 2 of the first OCT data and the second OCT data The positional relationship may be set by matching the FPN2 with image processing. In this case, the controller 70 may combine the combined OCT data so that the FPN1 of the first OCT data and the FPN1 of the second OCT data match in the depth direction.

  In the present embodiment, in the FPN generation optical system 200, the first optical path 203 in which the first optical member 204 is disposed and the second optical path 205 in which the second optical member 206 is disposed are equal to each other. The optical dispersion amount is set (constructed). As a result, since the PSF signal by FPN has a similar shape, for example, even when the quality of the light source is poor and the PSF is not unimodal, the corresponding peak position can be easily detected and the separation can be easily determined. .

  FIG. 6 can also be considered as an example in which image synthesis is performed using one FPN. The generation of FPN1 is not necessarily essential. That is, even if the FPN optical system 200 of the present embodiment includes a single optical member for generating FPN, image composition is possible and the configuration of the apparatus can be simplified. The imaging range in the depth direction is narrower than when it is used, and the overlapping area between different OCT data increases. On the other hand, when providing a common area, by using a plurality of FPN signals, the imaging range in the depth direction can be widened, and the overlapping area between different OCT data can be reduced. In addition, a discontinuous area may be included. Also in this case, since the distance between the two can be accurately determined, it is useful, for example, when examining an eye accommodation function.

  In the FPN generation optical system 200 according to the present embodiment, the optical members for FPN generation (for example, the first optical member 204 and the second optical member 206) used for the synthesis of the OCT data are arranged in the air. Since the FPN generated by the surface reflection is used for image synthesis, as a result, it is possible to reduce the decrease in the signal strength (SNR) of the FPN, so that the OCT data using the FPN is accurately synthesized. be able to.

  The timing for obtaining the FPN signal may be implemented, for example, when the power is turned on, or may be implemented every time the subject is changed. Further, it may be performed at the time of optimization control for optimizing imaging conditions in the OCT optical system. Of course, the present invention is not limited to this and may be always performed. For example, the control unit acquires OCT data including the FPN signal in advance, and performs synthesis of the OCT data acquired later, correction of the mapping state, polarization adjustment, and the like using the previously acquired FPN signal. May be.

<Light shielding member>
Note that a light blocking member or a light reducing member may be disposed in the optical path of the FPN generation optical system 200 to reduce the FPN signal of OCT data used for observation or imaging of the eye to be examined. In this case, the FPN signal on the OCT data may be reduced by blocking or dimming at least one of the first optical path and the second optical path. These are effective in obtaining OCT data used for diagnosis and observation. Further, the present invention is not limited to this, and the FPN signal included in the OCT data may be removed by signal processing.

  For example, the optical path of the FPN generation optical system 200 includes a first light shielding member 210 for shielding the first optical path and a second light shielding member 212 for shielding the second optical path in each optical path. On the other hand, it may be arranged to be detachable.

<Correction of wave number mapping>
FIG. 7 is a diagram illustrating an example of the OCT data according to the present embodiment, and the first FPN signal and the second FPN signal are simultaneously formed on the OCT data. Note that the OCT data may include an OCT image of the eye to be examined.

  In this case, the control unit 70 processes a signal including both the first FPN and the second FPN at the same time, and acquires correction information for correcting the mapping state of each wave number component. That is, the control unit 70 may be used as an arithmetic processor that obtains correction information, for example. Further, the correction information may be acquired by a processor different from the control unit that drives the OCT optical system. Note that the control unit 70 generates correction information by using phase difference information of at least two FPN signals that are associated with the wavelength being swept by the light source 102 during or before the OCT image is captured. Also good.

  More specifically, the control unit 70 corrects the mapping state (wave number sampling mapping) of each wavelength component (wave number component) with respect to the sampling point p based on at least two FPN signals generated by the FPN generation optical system 200. May be.

  For example, the control unit 70 may obtain φ (k) in the spectrum signal at the position corresponding to the FPN by analyzing the intensity level of the FPN. φ (k) indicates a change in the phase φ of the spectrum signal according to the sweep wavelength (wave number). φ (k) may be represented by a function having a horizontal axis: wave number k and a vertical axis: phase φ. Polynomial fitting may be performed on φ (k) in the wave number k region where the signal strength (amplitude) is large, and φ (k) in the wave number k region where the signal strength is low may be obtained by extrapolation or interpolation. For example, φ (k) may be obtained from Arc Tangent (inverse tangent) of the ratio of the real part RealF and the imaginary part ImagF of the Fourier transform value (intensity value) F at the depth position corresponding to the FPN. Here, arc tangent of the ratio of the real part and the imaginary part of the Fourier transform value is calculated by Arc Tangent processing, and φ (k) is obtained.

  When at least two FPN signals are obtained at the same time, the control unit 70 processes the first FPN to obtain the first wave number mapping information φ1 (k), and processes the second FPN to obtain the second wave number. Mapping information φ2 (k) may be obtained (see FIG. 8). In this case, each wave number mapping information may be obtained as phase information of each wave number component.

  Further, the control unit 70 may obtain difference information Δφ (k) between the first wave number mapping information φ1 (k) and the second wave number mapping information φ2 (k) (see FIG. 5). The difference information may be obtained as phase difference information of each wave number component. When obtaining the difference information Δφ (k), since the phase advance of the second FPN is faster, the difference information may be obtained by Δφ (k) = φ2 (k) −φ1 (k). In addition, the dispersion | distribution component contained in each wave number mapping information can be canceled by calculating | requiring difference information. In this case, as described above, it is preferable that the amount of dispersion between the first optical path 203 and the second optical path 205 be equal.

  Here, if the optical distance (optical path length difference) between the first FPN and the second FPN is ΔZ, and the difference information Δφ (k) is ideal, the following equation (1)

It should be a straight line as shown in.

  Here, ΔZ is obtained as follows. The interference component can be generalized as exp (ikz), and k and z have a relationship of kz = 2π. From this, z is the following equation (2), where N is the number of sampling points and kmax and kmin are the maximum and minimum values of the k value detected at each sampling point.

Can be expressed as: I = 0, 1, 2,..., N / 2
If an interference signal corresponding to ΔZ is detected at a sampling point corresponding to i (ΔZ), ΔZ is expressed by the following equation (3).

It can be expressed as.

  Since Δφ (k) should ideally be a straight line with a slope ΔZ and an intercept 0, assuming that the second-order and third-order nonlinear terms are σ, k is expressed by the following equation (4):

It is corrected. The corrected wavelength λ ′ is determined as λ ′ = 2π / k ′. Where σ is the following equation (5)

And the nonlinear term σ = b ₂ k ² + b ₃ k ³ when expanded. In the above example, the nonlinear term is the third order. However, the present invention is not limited to this, and more nonlinear terms may be used. For example, it may be about the 9th order. Alternatively, another fitting method (a fitting method using a chirped sine wave) may be used.

FIG. 9 is a diagram schematically illustrating mapping of spectrum signals to be corrected by performing correction calculation. Further, the corrected values of Δφ (kmin) and Δφ (kmax) are within a predetermined allowable range (for example, about 1E- ⁵ ) from the ideal values z (peak) · kmin, z (peak) · kmax. If so, it is determined that it has converged. If this condition is not satisfied, the same calculation is repeated again using the above-mentioned corrected λ ′.

  As described above, the control unit 70 may obtain correction information from at least two FPN signals generated by using the FPN generation optical system 200 by calculation, and store the obtained correction information in the memory 72. Thereby, the correspondence between each wavelength component detected by the detector 120 and each sampling point is obtained more accurately. The obtained correction information may be used for acquiring OCT data. For the method of obtaining φ (k) from FPN and the method of obtaining wave number mapping information, refer to JP2013-156229A, JP2015-68775A, and the like.

  In the above description, the case where the wave number mapping information is corrected in SS-OCT is shown. However, the present invention is not limited to this, and the present embodiment can be applied to the case where wave number mapping information is corrected in SD-OCT. It is. In this case, for example, the control unit 70 may correct the mapping state for each wavelength (wave number) for each light receiving element of the spectrometer based on at least two FPN signals generated by the FPN generation optical system 200. . In this case, JP 2010-220774 A may be referred to.

  For the wave number mapping correction according to this embodiment, refer to Japanese Patent Application No. 2017-0117156.

  In addition, as timing which acquires the correction information for correcting the mapping state of each wave number component, for example, it may be performed when the power is turned on, or may be performed every time the subject is changed. Further, it may be performed at the time of optimization control for optimizing imaging conditions in the OCT optical system. Of course, the present invention is not limited to this and may be always performed. Note that after correction of the mapping state, the FPN on the OCT image may be removed by noise removal processing.

  In the above description, the FPN generation optical system is provided at a position branched from the measurement optical path. For example, the FPN generation optical system may be arranged at a position branched from the reference optical path of the OCT optical system. In this case, for example, an FPN signal due to interference between light from the FPN generation optical system and reference light (or measurement light) may be obtained. Further, for example, the FPN generation optical system may be arranged at a position branched from the optical path after the measurement optical path and the reference optical path merge. In this case, for example, an FPN signal is obtained by interference between the interference light that goes directly to the optical path of the interference light and the interference light from the FPN generation optical system provided at a position branched from the optical path of the interference light. May be detected. In addition, when the detector 120 includes the first detector 120a and the second detector 120b, the FPN generation optical system is arranged before being divided into the optical paths of each detector, so that each detector A similar FPN signal may be detected.

<Application example to the eye to be examined>
This apparatus may be an ophthalmic OCT apparatus for acquiring OCT data of an eye to be examined. For example, the ophthalmic OCT apparatus may be configured to be able to acquire fundus OCT data and anterior segment OCT data including the cornea and the lens, and based on the cornea and fundus OCT data. The structure which can measure axial length is also possible.

  For example, the ophthalmic OCT apparatus may be configured such that the optical arrangement of the OCT optical system 100 can be switched in accordance with an automatic or manual mode switching signal. Hereinafter, an example in which the mode is switched among the fundus photographing mode, the anterior segment photographing mode, and the axial length measurement mode will be described.

<Fundus photography mode>
When the fundus photographing mode is set, the control unit 70 may control the light guide optical system 150 and switch to an optical arrangement for obtaining fundus OCT data. In this case, for example, the control unit 70 optically arranges the light guide optical system 150 so that the turning point of the measurement light is formed on the eye pupil to be examined and the condensing position of the measurement light is formed on the fundus. May be switched. For the configuration related to the switching of the optical arrangement of the light guide optical system 150, see, for example, Japanese Patent Application Laid-Open No. 2006-209577.

  When the fundus imaging mode is set, the control unit 70 may adjust the optical path length of at least one of the measurement light and the reference light, and set the OCT data acquisition region in the fundus. In this case, for example, the control unit 70 sets the measurement light and the reference light so that the optical path length of the reference light passing through at least one of the plurality of reference optical paths matches the optical path length of the measurement light passing through the fundus. The optical path length difference between them may be adjusted. When the optical path length difference is adjusted, the OCT data may be adjusted so that the retina is formed on the back side with respect to the zero delay position, or the choroid may be on the front side with respect to the zero delay position. It may be adjusted so that the OCT data is acquired in the formed state.

  In the present embodiment, for example, the measurement is performed by moving the optical member disposed in the measurement optical path so that the optical path length of the measurement light from the fundus coincides with the reference light from the first reference optical path 110a. The optical path length of light may be adjusted. Thereby, at least the first OCT data obtained based on the output signal from the first detector 110a includes fundus OCT data.

  FIG. 10 is a diagram illustrating an example of OCT data acquired in the fundus imaging mode. The control unit 70 may move the optical member 112 and adjust the optical path length of the second reference optical path 110b so as to have the same optical path length as that of the first reference optical path 110a. As a result, the first OCT data based on the first detector 110a and the second OCT data based on the second detector 110b become the same region of the fundus. In this case, the control unit 70 may obtain synthesized OCT data (for example, an addition average image, a super-resolution image, etc.) based on the first OCT data and the second OCT data. Thus, good fundus OCT data regarding a predetermined imaging region can be obtained in a short time.

<Ocular length measurement mode>
When the axial length measurement mode is set, the control unit 70 may control the light guide optical system 150 to switch to the same optical arrangement as the above-described fundus photographing mode. In this case, for example, the control unit 70 switches the optical arrangement of the light guide optical system 150 so that the turning point of the measurement light is formed on the pupil and the condensing position of the measurement light is formed on the fundus. May be. Thereby, in the OCT data obtained at the time of measuring the axial length, the fundus morphology information (for example, information around the macula) can be acquired in detail, and as a result, the axial length of the eye to be examined can be accurately measured. .

  When the axial length measurement mode is set, the control unit 70 adjusts the optical path length of at least one of the measurement light and the reference light, and the OCT data by one of the first detector 120a and the second detector 120b. May be set on the fundus and the OCT data acquisition region by the other of the first detector 120a and the second detector 120b may be set on the cornea.

  FIG. 11 is a diagram illustrating an example of OCT data acquired in the axial length imaging mode. In the present embodiment, for example, the measurement is performed by moving the optical member disposed in the measurement optical path so that the optical path length of the measurement light from the fundus coincides with the reference light from the first reference optical path 110a. The optical path length of light may be adjusted. Thereby, at least the first OCT data obtained based on the output signal from the first detector 110a includes fundus OCT data.

  In a state in which the position of the optical member arranged in the measurement optical path is adjusted so that the first OCT data includes the fundus OCT data, for example, the control unit 70 includes the optical path length of the measurement light from the cornea, By moving the optical member 112 disposed in the second reference optical path 110b so that the reference light from the second reference optical path 110b matches, the optical path length of the reference light in the second reference optical path 110b is increased. It may be adjusted. Accordingly, the second OCT data obtained based on the output signal from the second detector 110b includes the corneal OCT data.

  When the fundus OCT data and the cornea OCT data are acquired, the control unit 70 may detect the retinal position based on the fundus OCT data and may detect the cornea position based on the cornea OCT data. The control unit 70 may measure the axial length using the detection result of the retinal position, the detection result of the corneal position, and the optical path length difference between the first reference optical path 110a and the second reference optical path 110b. .

  In this case, for example, the optical path length difference between the first reference optical path 110a and the second reference optical path 110b may be obtained by the drive position of the drive unit for moving the optical member 112, or It may be detected based on the position. When the optical path length difference between the first reference optical path 110a and the second reference optical path 110b is fixed, a known optical path length difference may be used. In addition, the FPN generation optical system 200 is not limited to this, and includes an FPN generation optical member for generating an FPN signal corresponding to the cornea and an FPN generation optical member for generating an FPN signal corresponding to the fundus. Alternatively, the optical path length difference may be acquired using the position of a known optical member. In this case, three or more FPN generating optical members may be used to cope with the optical path length difference.

<Anterior segment photography mode>
When the anterior segment imaging mode is set, the control unit 70 may control the light guide optical system 150 to switch to an optical arrangement for obtaining OCT data of the anterior segment including the cornea and the crystalline lens. In this case, the optical arrangement of the light guide optical system 150 is switched so that the turning point of the measuring light is formed on the apparatus side of the eye pupil to be examined and the condensing position of the measuring light is formed on the anterior eye part. May be. For the configuration related to the switching of the optical arrangement of the light guide optical system 150, see, for example, Japanese Patent Application Laid-Open No. 2006-209577.

  When the anterior segment imaging mode is set, the control unit 70 adjusts the optical path length of at least one of the measurement light and the reference light, and the first detector 120a and the second detector 120b. The OCT data acquisition region by one of the first detector 120a and the second detector 120b may be set in the cornea, and the OCT data acquisition region by the other one may be set in the cornea. Here, the OCT data acquired by the first detector 120a and the OCT data acquired by the second detector 120b differ in at least a part of the acquisition region on the eye to be examined with respect to the depth direction. Thereby, OCT data including the cornea region and OCT data including the lens region may be acquired. In this case, the OCT data including the cornea region may include at least the cornea and the front surface of the lens, and the OCT data including the lens region may include at least the rear surface of the lens. That is, the OCT data of the front region in the anterior eye region and the OCT data of the rear region in the anterior eye region may be acquired separately.

  The control unit 70 may synthesize, for example, OCT data including the crystalline lens region and OCT data including the corneal region. In this case, the above-described synthesis process using the FPN signal may be used, so that the optical path length of the measurement light from the cornea and the crystalline lens coincides with the optical path length of the measurement light passing through the FPN generation optical system 200. The optical path length of the FPN generation optical system 200 may be set. In other words, in the state in which the optical path length difference between the measurement light of the light guide optical system 150 and the reference light is set so that OCT data including the cornea region and OCT data including the lens region can be acquired, FPN is added to each OCT data. The FPN generation optical system 200 may be set so that the signal is included.

  When the optical path length difference is adjusted, adjustment is made so that OCT data including the cornea region is acquired in a state where the front surface of the cornea is formed on the back side with respect to the zero delay position. It may be adjusted so that OCT data including the crystalline lens region is acquired in a state of being formed on the front side. Thereby, the influence by the mirror image at the time of image composition can be avoided. In addition, the first reference optical path 110a and the second reference optical path 110b are arranged so that a part of the acquisition region on the eye to be examined overlaps in the depth direction between the first OCT data and the second OCT data. The optical path length difference may be set. Thereby, connection in image composition can be performed smoothly.

  FIG. 12 is a diagram illustrating an example of OCT data acquired in the anterior ocular segment imaging mode. In the present embodiment, for example, the measurement is performed by moving the optical member arranged in the measurement optical path so that the optical path length of the measurement light from the crystalline lens matches the reference light from the first reference optical path 110a. The optical path length of light may be adjusted. Accordingly, at least the first OCT data obtained based on the output signal from the first detector 110a includes the OCT data of the crystalline lens region.

  In a state in which the position of the optical member arranged in the measurement optical path is adjusted so that the first OCT data includes the OCT data of the crystalline lens, for example, the control unit 70 includes the optical path length of the measurement light from the cornea, By moving the optical member 112 disposed in the second reference optical path 110b so that the reference light from the second reference optical path 110b matches, the optical path length of the reference light in the second reference optical path 110b is increased. It may be adjusted. Accordingly, the second OCT data obtained based on the output signal from the second detector 110b includes the corneal OCT data.

  When the OCT data of the crystalline lens and the OCT data of the cornea are acquired, for example, the control unit 70 may synthesize the OCT data of the crystalline lens and the OCT data of the cornea to acquire the combined OCT data. Furthermore, the control unit 70 may detect the corneal position, the lens position, and the like based on the synthetic OCT data, and measure the anterior chamber depth, the lens thickness, and the like of the eye to be examined.

<Correction of OCT data using FPN signal included in other OCT data>
The control unit 70 acquires OCT data including the FPN signal in one of the first OCT data and the second OCT data, and the OCT not including the FPN signal in the other of the first OCT data and the second OCT data. Data may be acquired. Further, the control unit 70 may obtain wave number mapping information based on the FPN signal in the OCT data including the FPN signal and correct the OCT data not including the FPN signal. According to this configuration, when a plurality of detectors are used, it is not always necessary to provide an FPN generation optical system according to each detector. In this case, the control unit 70 may correct the OCT data not including the FPN signal in real time, and according to this, the correction of the OCT data can be corrected with higher accuracy.

  In this case, for example, the control unit 70 adjusts the optical path length of at least one of the measurement light and the reference light, and sets an acquisition region of OCT data by one of the first detector 120a and the second detector 120b to a predetermined value. You may set to imaging | photography site | parts (for example, a fundus, a cornea, a crystalline lens). In addition, the control unit 70 sets an acquisition region of OCT data by the other of the first detector 120a and the second detector 120b in the optical member (for example, the optical member 204, the optical member 206) of the FPN generation optical system 200. To do.

  FIG. 13 is a diagram illustrating an example of applying real-time correction in the fundus photographing mode. For example, the control unit 70 adjusts the optical path length of at least one of the measurement light and the reference light, and sets an acquisition region of OCT data by one of the first detector 120a and the second detector 120b in the fundus ( (Refer to fundus photographing mode above).

  In addition, the control unit 70 sets an acquisition region of OCT data by the other of the first detector 120a and the second detector 120b in the optical member (for example, the optical member 204, the optical member 206) of the FPN generation optical system 200. To do. In this case, the optical path length of the FPN generation optical system 200 is set to a length different from the optical path length of the measurement light that reaches the detector 120a via the fundus. For example, the control unit 70 determines the measurement light and the reference light so that the optical path length of the reference light that passes through at least one of the plurality of reference optical paths matches the optical path length of the measurement light that passes through the FPN generation optical system 200. The optical path length difference between the two may be adjusted.

  In the present embodiment, for example, the measurement is performed by moving the optical member disposed in the measurement optical path so that the optical path length of the measurement light from the fundus coincides with the reference light from the first reference optical path 110a. The optical path length of light may be adjusted. Thereby, at least the first OCT data obtained based on the output signal from the first detector 110a includes fundus OCT data.

  In addition, in the state where the position of the optical member arranged in the measurement optical path is adjusted so that the first OCT data includes the OCT data of the fundus, the control unit 70, for example, By moving the optical member 112 arranged in the second reference optical path 110b so that the optical path length of the measurement light from the optical member of the system 200 matches the reference light from the second reference optical path 110b. The optical path length of the reference light in the second reference optical path 110b may be adjusted. Thus, the second OCT data obtained based on the output signal from the second detector 110b includes OCT data including the FPN signal. In this case, as a result, signals such as a cornea and a crystalline lens may be included in addition to the FPN signal.

  In the above description, the application example in the fundus imaging mode has been described. However, the present invention is not limited to this, and the above configuration may be applied in other imaging modes.

  In the above description, the OCT data including the FPN signal (for example, only the FPN signal) is acquired from one of the first OCT data and the second OCT data, and the first OCT data and the second OCT data On the other hand, when OCT data of an eye to be examined that does not include an FPN signal is acquired, the light path length adjustment is not limited to the above, and a light shielding member may be used. For example, the control unit 70 may obtain first OCT data that does not include FPN (for example, FPN1) by arranging the light blocking member 210 in the first optical path. In this case, since the light shielding member 212 is removed from the second optical path, second OCT data including FPN (for example, FPN2) is obtained. When only the FPN signal is obtained, correction using the FPN signal can be performed with high accuracy.

<Polarization adjustment>
The control unit 70 controls the polarization adjustment unit (for example, the first polarization adjustment unit 300, the second polarization adjustment unit 302, and the third polarization adjustment unit 304), and adjusts the polarization state when obtaining the OCT data. You may do it. The timing for adjusting the polarization state may be implemented, for example, when the power is turned on, or may be implemented every time the subject is changed. Further, it may be performed at the time of optimization control for optimizing imaging conditions in the OCT optical system.

  Hereinafter, the adjustment of the polarization state in the anterior segment imaging mode will be described as an example. FIG. 14 is a diagram illustrating an example of OCT data when polarization adjustment is performed in the anterior segment imaging mode. First, the control unit 70 controls the second polarization adjustment unit 302 to adjust the polarization state so that the signal intensity of the corneal image in the second OCT data is maximized. Thereby, a cornea image in the second OCT data is acquired with a good signal intensity.

  FIG. 15 is a diagram showing an example of FPN signal strength. Next, the control unit 70 controls the third polarization adjustment unit 304 to adjust the polarization state so that the signal intensity of the FPN signal in the second OCT data is maximized. Thereby, the FPN signal in the second OCT data is acquired with a good signal strength. As a result, the cornea image and the FPN signal in the second OCT data are acquired with good signal strength.

  Next, the control unit 70 controls the first polarization adjusting unit 300 so that the signal intensity ratio between the FPN signal in the second OCT data and the FPN signal in the first OCT data is a predetermined signal intensity ratio. (For example, the polarization state is adjusted so that the signal intensity ratios are equal to each other.) As a result, the FPN signal in the first OCT data is acquired with a good signal strength, and the crystalline lens image in the first OCT data is acquired with a good signal strength.

  According to the control as described above, the balance of the signal intensity between the first OCT data and the second OCT data can be adjusted. Further, in the adjustment of the polarization state of the OCT data including the crystalline lens, the polarization state using the crystalline lens image is obtained by using the signal intensity ratio between the FPN signal in the second OCT data and the FPN signal in the first OCT data. The polarization state is adjusted with higher accuracy than adjusting the. That is, the crystalline lens image in this case may be limited to only information on the rear surface of the crystalline lens, and since the amount of information as an image is relatively small, the accuracy as a signal evaluation value may be low. As a result, it may not be possible to adjust to a good polarization state. On the other hand, since the FPN signal is used, a stable signal strength can be secured, so that the accuracy as the signal evaluation value can be secured, and the polarization state can be adjusted well.

  In addition, in the case of the polarization state optimized only for the information on the back surface of the lens, a mismatch of the detected polarization occurs between the first OCT data and the second OCT data, thereby causing a connection region between the two. As a result, an intensity signal gap is generated. This is remarkable, for example, when the lens is in the gap position. In other words, the intensity signal of the lens (generally weak) becomes discontinuous, which can be fatal when trying to quantitatively evaluate turbidity. On the other hand, if the mismatch of the polarization detected between the first OCT data and the second OCT data is eliminated according to the present embodiment, such a gap does not occur.

  In the above description, since the FPN signal can be detected with high accuracy by adjusting the polarization state of the FPN generation optical system, various processes using the FPN signal can be appropriately performed.

  In the above description, the polarization state relating to the OCT data including the crystalline lens is adjusted using the FPN signal. However, the present invention is not limited to this, and the polarization state may be adjusted using the signal intensity of the entire crystalline lens image in the OCT data. Good.

  In the above description, when the first detector 120a and the second detector 120b are used, the OCT data obtained by the first detector 120a and the OCT data obtained by the second detector 120b Each OCT data can be acquired with a good signal intensity by adjusting the polarization state. Of course, the present invention is not limited to this, and the polarization state may be adjusted only for one of the OCT data.

  Moreover, when using any one of the 1st detector 120a and the 2nd detector 120b, a polarization state may be adjusted regarding the OCT data obtained by the detector used, for example.

<Wide-angle fundus shooting mode>
The fundus imaging mode may be a wide-angle fundus imaging mode for obtaining OCT data in a wide-angle region including the fundus center and the fundus periphery. Further, the normal fundus photographing mode as described above and the wide-angle fundus photographing mode may be switched. In the wide-angle fundus photographing mode, the scanning range of the measurement light on the fundus by the optical scanner 156 may be set to a wide-angle region including the center and the periphery of the fundus. In this case, a lens attachment for wide-angle shooting may be used.

  FIG. 16 is a diagram illustrating an example of OCT data acquired in the wide-angle fundus imaging mode. When the wide-angle fundus photographing mode is set, the control unit 70 adjusts the optical path length of at least one of the measurement light and the reference light, and obtains the OCT data acquisition region by the first detector 120a and the second detector 120b. May be set to a wide-angle region including the center of the fundus and the periphery of the fundus. For example, the control unit 70 sets the acquisition region of the OCT data by the first detector 120a in the center of the fundus and sets the acquisition region of the OCT data by the second detector 120b in the periphery of the fundus. Good. In the present embodiment, the first OCT data may be acquired by the first detector 120a, and the second OCT data may be acquired by the second detector 120b.

  Here, the eye has a spherical shape centered on the center of the eyeball, and the fundus has a concave shape with the center of the fundus at the bottom. However, the measurement light is swiveled around the center of the pupil to scan the fundus. Is done. In this case, the optical path length from the scanning center to the fundus periphery is shorter than the optical path length from the scanning center to the fundus center. Normally, the imageable range in the depth direction when obtaining the OCT data is a predetermined distance from the zero delay position, and when the fundus is scanned at a wide angle, there is a possibility that the imageable range is deviated from the imageable range in the depth direction.

  Therefore, for example, the optical path length difference between the first reference optical path 110a and the second reference optical path 110b is set in consideration of the optical path length difference between the fundus center and the fundus periphery, and the eye to be examined By adjusting the optical path length difference between the measurement light and the reference light with respect to the fundus, first OCT data including OCT data in the center of the fundus, second OCT data including OCT data in the vicinity of the fundus, Can be acquired. In this case, for example, the optical path length of the first reference optical path 110a is set in accordance with the optical path length of the measurement light from the center of the fundus, and the optical path length of the second reference optical path 110b is the measurement light from the periphery of the fundus. It may be set according to the optical path length. In this case, in consideration of the eyeball shape, the optical path length of the reference optical path 110b corresponding to the fundus periphery may be set shorter than the reference optical path 110a corresponding to the fundus center. Of course, in some cases, the optical path length of the reference optical path 110b corresponding to the fundus periphery may be set longer than the reference optical path 110a corresponding to the fundus center.

  For example, the OCT data of the fundus periphery included in the second OCT data is the OCT data in which the OCT data in the center of the fundus included in the first OCT data is continuous in at least one of the transverse direction and the depth direction at the end. It may be data. In this case, for example, part of each other's OCT data may be OCT data that overlaps at least one of the transverse direction and the depth direction and is continuous at the end. Note that the optical path length difference between the first reference optical path 110a and the second reference optical path 110b when obtaining the OCT data in the wide-angle region may be fixed or variable.

  For example, the first OCT data includes OCT data in a first fundus region including at least the macular region and the papilla of the fundus, and the second OCT data is outside of both ends of the first fundus region. Each region may be included. Further, the present invention is not limited to this, and the first OCT data includes OCT data in the first fundus region including at least the macular region of the fundus, and the second OCT data is obtained from both ends of the first fundus region. May also include outer regions, respectively.

  For example, the first OCT data and the second OCT data may have different data acquisition regions on the eye in the depth direction. In this case, between the first OCT data and the second OCT data, The optical path length difference between the first reference optical path 110a and the second reference optical path 110b may be set so that a part of the acquisition area on the eye to be examined overlaps in the depth direction. As a result, the connection process when the first OCT data and the second OCT data are combined can be performed smoothly.

  FIG. 17 is a diagram illustrating an example of combining OCT data acquired in the wide-angle fundus imaging mode. For example, the control unit 70 may acquire wide-angle OCT data based on the first OCT data and the second OCT data by combining the first OCT data and the second OCT data. In this case, the first OCT data and the second OCT data may be combined so as to be continuous in the depth direction.

  In this case, the control unit 70 may perform the synthesis process using the FPN signal described above, and the optical path length of the measurement light from the center and the peripheral part of the fundus and the measurement light that has passed through the FPN generation optical system 200. The optical path length of the FPN generation optical system 200 may be set so that the optical path lengths match.

  A state in which the optical path length difference between the measurement light and the reference light is set so that the first OCT data including the OCT data in the center of the fundus and the second OCT data including the OCT data in the vicinity of the fundus can be acquired. The FPN generation optical system 200 may be set so that each OCT data includes an FPN signal.

  Note that the synthesis process is not limited to the process using FPN. For example, the control unit 70 performs the first process by the matching process using the overlapping area between the first OCT data and the second OCT data. Data composition may be performed by defining the positional relationship between the OCT data and the second OCT data. In addition, the control unit 70 defines the positional relationship between the first OCT data and the second OCT data by using the optical path length difference between the first reference optical path 110a and the second reference optical path 110b. Synthesis may be performed. At this time, if there is an overlapping region, a signal with higher sensitivity may be adopted, or a side with less noise artifact may be adopted. Further, various kinds of smoothing processing may be performed at the connection portion so that a sudden change does not occur at the connection portion.

<Wide-angle shooting with one B-scan>
The control unit 70 controls the optical scanner 156, and scans the measurement light in a wide-angle region including the center portion and the peripheral portion of the fundus oculi by one B scan, and the first B scan OCT data and the second B scan. OCT data may be acquired (see FIG. 16).

  For example, when one B scan from the start point A to the end point D in the horizontal direction is performed, when the fundus region near the point B is scanned from the start point A, the output signal from the second detector 120b is used. Then, OCT data based on the reflected light and the reference light from the fundus periphery (left side) is acquired. Further, based on the output signal from the first detector 120a, OCT data based on reflected light and reference light from the fundus central part close to the fundus peripheral part (left side) is acquired.

  Next, when the fundus region from the vicinity of point B to the vicinity of point C is scanned, OCT data based on the reflected light from the center and the reference light is acquired based on the output signal from the first detector 120a. The Further, when the fundus region from the vicinity of the point C to the end point D is scanned, OCT data based on the reflected light and the reference light from the peripheral portion (right side) is acquired based on the output signal from the second detector 120b. Is done. Further, based on the output signal from the first detector 120a, OCT data based on the reflected light and the reference light from the fundus central part close to the fundus peripheral part (right side) is acquired.

  According to the above control, B-scan OCT data in a wide-angle region can be acquired smoothly. In this case, wide-angle B-scan OCT data may be acquired by combining the acquired first OCT data and second OCT data.

  In addition, B scans may be performed for a plurality of wide-angle regions on the fundus (for example, cross scan, multiline scan, radial scan, etc.). However, the present invention is not limited to this, and the wide-angle region including the fundus central part and the fundus peripheral part is divided into a plurality of times and B scan is performed to obtain the first B scan OCT data and the second B scan OCT data. May be.

  In addition, the control unit 70 scans the measurement light in a wide-angle region including the fundus central part and the fundus peripheral part in each scanning line by one raster scan, and performs the first three-dimensional OCT data and the second three-dimensional data. OCT data may be acquired. In this case, the measurement light is scanned with respect to a plurality of scanning lines constituting the raster scan. Each scanning line may have a scanning range corresponding to the wide-angle region. Thereby, the three-dimensional OCT data in the wide-angle region can be acquired smoothly. In this case, for example, the control unit 70 scans the measurement light a plurality of times for each scanning line constituting the raster scan, and based on a plurality of temporally different OCT data in each scanning line, a three-dimensional motion contrast at a wide angle. OCT data (OCT angio data) may be acquired.

  Note that the scanning range in one B-scan is not limited to the scanning range for the front image shown in FIG. 16, and this embodiment can also be applied to scanning a wide-angle fundus region. Needless to say. In this case, two reference optical paths may be used, or three or more reference optical paths may be used.

<Optical path length adjustment>
Hereinafter, an example of the optical path length adjustment in the wide-angle fundus photographing mode will be described below. In the present embodiment, for example, the optical member arranged in the measurement optical path is arranged so that the optical path length of the measurement light from the center of the fundus and the optical path length of the reference light from the first reference optical path 110a substantially coincide with each other. Thus, the optical path length of the measurement light may be adjusted. Thus, at least the first OCT data obtained based on the output signal from the first detector 110a includes OCT data including the fundus center.

  In a state where the position of the optical member arranged in the measurement optical path is adjusted so that the OCT data of the fundus center is acquired, for example, the control unit 70 determines the optical path length of the measurement light from the fundus periphery and the second By arranging the optical member 112 arranged in the second reference optical path 110b so that the optical path length of the reference light from the reference optical path 110b of the second reference optical path 110b substantially coincides, the optical path of the reference light in the second reference optical path 110b The length may be adjusted. As a result, the second OCT data obtained based on the output signal from the second detector 110b includes OCT data of the fundus periphery. In the above, instead of adjusting the optical path length of the measurement light, the optical path length of the reference light of the first reference optical path 110a may be adjusted.

<First embodiment regarding optical path length setting>
The optical path length of the first reference optical path 110a may be set so that the first OCT data is acquired in a state where the choroid at the center of the fundus is formed in front of the zero delay position (see FIG. 16). . According to this, for example, the deterioration of the choroid image due to sensitivity attenuation is reduced in the OCT data at the center of the fundus, and the mixing of the mirror image (virtual image) and the real image in the first OCT data can be reduced. .

  Further, the optical path length of the second reference optical path 110b may be set such that the second OCT data is acquired in a state where the retina in the vicinity of the fundus is formed on the back side with respect to the zero delay position (FIG. 16). According to this, for example, it is possible to reduce the deterioration of the image due to the decrease in the amount of light in the fundus periphery, and to reduce the mixture of the mirror image (virtual image) and the real image in the second OCT data.

  Note that when OCT data is obtained in a wide-angle region, the tendency that the amount of light decreases as it goes to the periphery appears prominently. This is because, due to the characteristics of the objective optical system, the center of the pupil does not necessarily match the fundus curvature, and there is a divergence between the direction of the irradiated light and the direction of the reflected and scattered light as it moves away from the center. It is because it ends. For example, the amount of return light at the position farthest from the center in the fundus periphery is the lowest. This is because, in the fundus OCT image, a saturated portion due to surface reflection occurs near the center where light is irradiated perpendicularly to the surface and coincides with the direction of the detection system, whereas this phenomenon is not seen in the peripheral portion. It is clear from As a result, the signal intensity at the fundus periphery tends to be lower than that at the fundus center. Furthermore, it is generally known that the optical performance of the light projecting system is reduced due to the occurrence of aberration as it becomes off-axis, and in view of the influence thereof, it can be said that the return light amount at the outermost periphery is unavoidable. The effect is not linear, and contributes at least by the square of the half angle of view, so that it becomes prominent as the system is widened.

  Therefore, considering the tendency that the amount of return light decreases toward the periphery and the sensitivity characteristic in the depth direction that the sensitivity increases as it approaches the zero delay position, the retina around the fundus is deeper than the zero delay position. By setting the optical path length so that the second OCT data is acquired in the state formed on the side, the sensitivity can be increased toward the periphery. Can be reduced.

  The first OCT data is acquired with the choroid at the center of the fundus formed in front of the zero delay position, and the second OCT data, the retina at the fundus periphery is more than the zero delay position. By being formed on the back side, it is possible to reduce the mixture of the mirror image and the real image in both the first OCT data and the second OCT data, and obtain the entire OCT data in a wide-angle region with a good signal intensity. Can do.

<Second embodiment regarding optical path length setting>
In the above description, the technique for reducing the mixture of the mirror image and the real image is illustrated, but the present invention is not limited to this. FIG. 18 is a diagram showing another example of OCT data acquired in the wide-angle fundus imaging mode. For example, when acquiring the second OCT data, the choroid in the fundus periphery is formed in front of the zero delay position, and the retina in the fundus center is formed in the back of the zero delay position. An optical path length may be set for the. In this case, a mixture of a mirror image when the fundus center is scanned and a real image when the fundus periphery is scanned occurs, but the fundus is a planar tissue with a relatively small thickness. The overlapping range is small, and it may be possible to use in fundus diagnosis by appropriately cutting out the use area.

  FIG. 19 is a diagram illustrating an example when the OCT data illustrated in FIG. 18 is synthesized. For example, when the first OCT data and the second OCT data are combined, the influence of the mirror image is generated by combining the peripheral data in the second OCT data and the central data in the first OCT data. Can be reduced.

  In addition to acquiring the second OCT data as described above, for example, when acquiring the first OCT data, the optical path length is set so that the choroid in the center of the fundus is formed in front of the zero delay position. May be set. As a result, the choroid side has high sensitivity in each OCT data, so that tissue changes in the choroid can be more easily discriminated in the wide-angle region.

<Third embodiment regarding optical path length setting>
For example, when acquiring the first OCT data, the optical path length is set so that the retina at the center of the fundus is formed on the back side with respect to the zero delay position, and at the periphery of the fundus from the zero delay position. The optical path length may be set so that the choroid is formed on the front side. In this case, a mixture of a mirror image when the fundus periphery is scanned and a real image when the fundus center is scanned occurs, but the fundus is a planar tissue having a relatively small thickness. The overlapping range is small and may be usable in fundus diagnosis.

  Further, for example, when the first OCT data and the second OCT data are combined, the peripheral image data in the second OCT data and the central portion data in the first OCT data are combined to create a mirror image. Can reduce the effects of

  In addition to acquiring the first OCT data as described above, for example, when acquiring the second OCT data, the optical path so that the retina in the fundus periphery is formed on the back side from the zero delay position. A length may be set. As a result, the retina side has high sensitivity in each OCT data, so that tissue changes in the retina can be more easily discriminated in the wide-angle region.

<Using multiple detectors for wide-angle photography>
FIG. 20 is a diagram illustrating an example when OCT data of the fundus center and the fundus periphery is obtained using a plurality of reference light paths and a plurality of detectors. FIG. 21 and FIG. 22 are diagrams showing an example when OCT data of the fundus center and the fundus periphery is obtained using one reference optical path and one detector. Note that ΔW in FIGS. 20 to 22 indicates a region where photographing can be performed while maintaining a predetermined amount of sensitivity with respect to the sensitivity at the zero delay position.

In this embodiment, by providing a reference optical path and detector for obtaining OCT data of the fundus central part and a reference optical path and detector for obtaining OCT data in the fundus peripheral part, OCT data around the fundus can be obtained simultaneously with good signal strength (see FIG. 20).
In this case, the first OCT data is acquired by one of the first detector 120a and the second detector 120b, and the second OCT is acquired by the other of the first detector 120a and the second detector 120b. Data may be acquired.

  In addition, when it is going to acquire OCT data of a fundus center part and a fundus periphery part simultaneously with only one reference optical path and one detector, the fundus center part is arranged in front of the zero delay position as a first configuration. (See FIG. 21), or as a second configuration, the fundus periphery may be arranged on the back side of the zero delay position (see FIG. 22). In this case, it is affected by the sensitivity attenuation characteristic in the depth direction in which the sensitivity decreases as the distance from the zero delay position increases, and the light intensity reduction characteristic in which the light intensity decreases toward the periphery.

  In the case of the first configuration, the retina and choroid near the center appear to have a relatively high contrast, but the image quality around the fundus is greatly reduced due to the double effect of the sensitivity attenuation characteristic and the light quantity reduction characteristic. Therefore, even if the image is taken at a wide angle, the sensitivity is not sufficient in the wide angle region, and the improvement of the diagnostic ability due to the wide angle must be limited. On the other hand, in the case of the second configuration, the retina and choroid near the periphery appear to have a relatively high contrast, but the image quality at the macula and papilla, which are important in fundus disease, is greatly reduced (see FIG. 21). In recent years, studies have been known that structural changes due to eye diseases appear in the vicinity of the choroid prior to the retina. In the case of the second configuration, the wide angle makes it possible to lower the diagnostic ability on the choroid side.

  In the above configuration, the detector is provided in each of the fundus central part and the fundus peripheral part. However, the detector may also be used in the fundus central part and the fundus peripheral part. The reference optical path may be selectively switched by an optical switch or the like. Even with such a configuration, OCT data of the fundus center and the fundus periphery can be obtained with good signal strength.

<Combination with anterior segment imaging mode>
In this embodiment, the reference optical path and detector for obtaining OCT data of the fundus central part and the reference optical path and detector for obtaining OCT data of the fundus peripheral part are arranged on the cornea and the front and rear surfaces of the lens. OCT data of the center and periphery of the fundus and OCT data of the anterior eye including the cornea and the front and back surfaces of the lens are obtained with good signal intensity by using the acquired OCT data of the anterior eye including OCT data for the entire eyeball can be obtained with good signal strength. Note that the anterior segment imaging mode has been described above, and a special description thereof will be omitted.

  Note that simultaneous detection is possible by using separate detectors for the cornea and the crystalline lens, but the cornea and the crystalline lens may also be used as a detector. In this case, for example, a plurality of reference optical paths are connected to an optical switch. It may be configured to selectively switch by, for example.

  In the above description, SS-OCT is taken as an example, but the present invention is not limited to this, and the present embodiment may be applied to SD-OCT. In this case, a plurality of spectrometers may be used as the plurality of detectors.

  In the above description, the OCT apparatus for imaging the eye to be examined is taken as an example. However, the present embodiment is not limited to this, and the present embodiment is applied to an OCT apparatus for imaging OCT data of the object to be examined. Also good. The test object may be, for example, a living body such as an eye (anterior eye portion, fundus, etc.), skin, or a material other than a living body.

It is a figure which shows an example of the OCT apparatus which concerns on a present Example. It is a figure which shows an example of the FPN production | generation optical system which concerns on a present Example. It is a figure which shows an example of the data at the time of synthesize | combining several OCT data using a FPN signal, and is a figure which shows before a synthesis | combination. It is a figure which shows an example of the data at the time of synthesize | combining several OCT data using a FPN signal, and is an image figure after a synthesis | combination. It is a figure which shows the example of a data change in the case of synthesize | combining several OCT data using a FPN signal. It is a figure which shows the example of a data change in the case of synthesize | combining several OCT data using a FPN signal. It is a figure which shows an example of OCT data used for wave number mapping correction | amendment. It is a figure which shows an example of the wave number mapping information obtained by processing FPN. It is a figure which shows an example for correct | amending a mapping state, when calculating | requiring the difference information (DELTA) (phi) (k) between 1st wave number mapping information (phi) 1 (k) and 2nd wave number mapping information (phi) 2 (k). It is a figure which shows an example of the OCT data acquired in fundus imaging mode. It is a figure which shows an example of the OCT data acquired in an axial length imaging | photography mode. It is a figure which shows an example of the OCT data acquired in anterior eye part imaging | photography mode. It is a figure which shows an example in the case of applying real time correction in fundus photography mode. It is a figure which shows an example of OCT data in case polarization adjustment is performed in the anterior ocular segment imaging mode. It is a figure which shows an example of the signal strength of FPN. It is a figure which shows an example of OCT data acquired in wide-angle fundus imaging mode. It is a figure which shows an example at the time of synthesize | combining the OCT data acquired in wide-angle fundus imaging mode. It is a figure which shows the other example of OCT data acquired in wide-angle fundus imaging mode. It is a figure which shows an example at the time of synthesize | combining the OCT data illustrated in FIG. It is a figure which shows an example at the time of obtaining OCT data of a fundus center part and a fundus periphery part using a plurality of reference light paths and a plurality of detectors. It is a figure which shows the example which concerns on a 1st structure at the time of obtaining OCT data of a fundus center part and a fundus periphery part using one reference optical path and one detector. It is a figure which shows the example which concerns on a 2nd structure at the time of obtaining OCT data of a fundus center part and a fundus periphery part using one reference optical path and one detector.

70 Operation Controller 100 OCT Optical System 110 Reference Optical System 120 Detector 200 FPN Optical System 300, 302, 304 Polarization Adjuster

Claims (8)

An OCT optical system that divides light from the OCT light source into a measurement optical path and a reference optical path, and detects an interference signal between the measurement light guided to the fundus of the eye to be examined via the measurement optical path and the reference light from the reference optical path by a detector; An OCT apparatus comprising: an image processor capable of processing a spectral interference signal output from the OCT optical system and acquiring OCT data;
The OCT optical system is
An OCT optical system that guides measurement light to a wide-angle region including a fundus center and a fundus periphery in one transverse direction in which the measurement light crosses over the fundus;
A first reference optical path having an optical path length set to obtain OCT data including the fundus center, and an optical path length set to obtain OCT data including the fundus periphery. A second reference optical path different from the reference optical path,
The image processor is
Based on an interference signal between the measurement light guided to the fundus center and the reference light from the first reference optical path, OCT data including the fundus center is obtained, and the OCT data guided to the fundus periphery is obtained. An OCT apparatus including OCT data including the fundus periphery based on an interference signal between measurement light and reference light from the second reference light path. The fundus center is an area including at least the macula and the nipple of the fundus,
2. The OCT apparatus according to claim 1, wherein the fundus peripheral part is an area including areas outside both ends of the fundus central part with respect to one transverse direction. The OCT optical system is
Optical scanning means for scanning the measurement light on the fundus of the eye to be examined,
The measurement light is scanned in a wide-angle region including the fundus center and the fundus periphery by one B-scan by the light scanning means, and OCT data including the fundus center and the OCT data including the fundus periphery are acquired. The OCT apparatus according to claim 2, wherein: The OCT optical system is
A first detector for detecting an interference signal between the measurement light guided to the fundus center and the reference light from the first reference light path;
A second detector different from the first detector, for detecting an interference signal between the measurement light guided to the fundus periphery and the reference light from the second reference light path; Two detectors;
The OCT apparatus according to claim 1, further comprising:   In the first reference optical path, first OCT data in a state where the choroid at the center of the fundus is formed in front of the zero delay position where the optical path lengths of the measurement light and the reference light coincide with each other is acquired. The OCT apparatus according to claim 1, wherein an optical path length is set.   In the second reference optical path, second OCT data in a state where the retina in the vicinity of the fundus is formed on the back side from the zero delay position where the optical path lengths of the measurement light and the reference light coincide with each other is acquired. An optical path length is set in the OCT apparatus according to claim 1. The OCT optical system is
Furthermore, the detector can detect an interference signal between the measurement light guided to the anterior ocular segment to be examined through the measurement optical path and the reference light from the reference optical path,
The first reference optical path and the second reference optical path are set to different optical path lengths, and one of the first reference optical path and the second reference optical path is for obtaining OCT data including the cornea of the eye to be examined. The other of the first reference optical path and the second reference optical path is set to an optical path length for obtaining OCT data including a crystalline lens of an eye to be examined. The OCT apparatus in any one of -6. The image processor is
8. The OCT apparatus according to claim 1, wherein the OCT data including the center of the fundus and the OCT data including the periphery of the fundus are combined to obtain wide-angle OCT data of the fundus of the eye to be examined.