WO2018203506A1

WO2018203506A1 - Optical coherence tomography apparatus

Info

Publication number: WO2018203506A1
Application number: PCT/JP2018/016842
Authority: WO
Inventors: 英之大番; 岩永　知行
Original assignee: キヤノン株式会社
Priority date: 2017-05-01
Filing date: 2018-04-25
Publication date: 2018-11-08
Also published as: JP2018187038A

Abstract

The present invention facilitates adjustment, etc., of a cylindrical lens disposed in a reference optical system in an LF-OCT apparatus. The LF-OCT apparatus according to the present invention is provided with: a division means for dividing light from a light source into measurement light and reference light; a first line image generation means that is disposed on the optical path of the measurement light and that generates a first line image of the measurement light; a second line image generation means that is disposed in the reference optical system for adjusting the optical path length of the reference light and that generates a second line image of the reference light, the optical path length of which has been adjusted; an interference means for generating interference light by synthesizing, on the same image-forming surface, the first line image and the second line image generated via an object being inspected; and a tomographic image generation means for generating, by using the generated interference light, a tomographic image of the object being inspected.

Description

Optical coherence tomography system

The present invention relates to an optical coherence tomographic imaging apparatus that acquires an optical coherence tomographic image of an inspection object.

In recent years, in the field of ophthalmology, an apparatus using an optical coherence tomography (OCT) (hereinafter referred to as an OCT apparatus) that can observe / measure a tomographic image of the fundus and anterior segment non-invasively has become widespread. In OCT, low-coherent light (measurement light) is irradiated to the eye, and information on the tomogram of the eye is obtained using interference light obtained by combining the return light from the eye and the reference light. Yes. Further, by scanning the measurement light over a predetermined range on the eye fundus of the eye to be examined, three-dimensional tomographic information in the predetermined range can be obtained. An OCT apparatus that embodies this method is widely used in medicine from research to clinical practice.

OCT is roughly classified into two types: time domain OCT and Fourier domain OCT. Further, the Fourier domain OCT includes a spectral domain OCT (SD-OCT) and a swept source OCT (SS-OCT). These Fourier domain OCTs use light from a light source having a wide wavelength band, perform signal acquisition by dispersing the obtained interference light, and perform processing such as Fourier transform on the acquired signal, thereby allowing the eye to be examined. Information on the fault is obtained. In SD-OCT using broadband light, information for each frequency is obtained by spatially spectroscopically using a spectroscope. In SS-OCT that uses light from a wavelength-swept light source, light from a light source that emits light having a different wavelength in time is spectrally dispersed to obtain information for each frequency.

For example, a line-field OCT apparatus (hereinafter referred to as an LF-OCT apparatus) that obtains tomographic information using measurement light that is shaped into a linear shape instead of using spot-like measurement light for the purpose of shortening measurement time. Has been proposed. Here, the optical system of the LF-OCT apparatus disclosed in Non-Patent Document 1 will be briefly described with reference to FIG.

In the optical system 200 of the LF-OCT apparatus, the light emitted from the wavelength sweep type light source 01 is guided to the line image generation system 201. In the line image generation system 201, the emitted light is converted into parallel light by the collimator lens 02 and then formed into light that forms a line-shaped image by the first cylindrical lens 03 and the lens 04 that are arranged subsequently. These configurations are arranged such that the line-shaped light forms a line image at a position that is conjugate with a predetermined diopter, for example, the fundus of the eye to be examined with 0 diopter. The line-shaped light is divided into measurement light and reference light by the beam splitter 12 after molding.

The measurement light is guided to the measurement optical system 203, forms a line image on the fundus of the eye 010 to be examined, is reflected and scattered, and returns to the beam splitter 12 from the fundus as return light again. The reference light is guided to the reference optical system 202. The reference light is converted into parallel light by a unit including the lens of the reference optical system 202 and the second cylindrical lens 07, and reaches the reference mirror 06 through the mirror unit 21 and the like disposed in the optical path of the reference light. In addition, in the optical path of the reference light, a polarization adjusting unit 25 composed of a wave plate or the like is also arranged in order to adjust the polarization of the reference light. The parallel light is reflected by the reference mirror 06, and then follows this optical path in reverse. Then, the light is again shaped into a line light by a unit such as the second cylindrical lens 07 and guided to the beam splitter 12. The measurement light (return light) that has passed through the fundus and the reference light that has passed through the optical path of the reference optical system are combined by the beam splitter 12, converted into line-shaped interference light, and guided to the detection optical system 204. The detection optical system 204 detects the line-shaped interference light by the line sensor 11 and outputs an interference signal. By performing signal processing on this interference signal, a tomographic image of the fundus of the eye to be examined can be acquired. Further, a three-dimensional tomographic image can be acquired by scanning the line-shaped measurement light in a direction different from (for example, perpendicular to) the extending direction of the line.

In the LF-OCT apparatus disclosed in Non-Patent Document 1, the first cylindrical lens 03 is arranged so that the measurement light forms a line image on the fundus of the subject eye 010 having a predetermined diopter. The first cylindrical lens 03 is disposed before the light emitted from the wavelength-swept light source 01 is divided into measurement light and reference light by the beam splitter 12, and is guided to the beam splitter 12 as light connecting a line image. It is burned. The reference light split by the beam splitter 12 is corrected by the reference optical system 202 so that the optical path length of the measurement light with respect to the fundus of the eye 010 to be imaged is equal to the optical path length. Then, as described above, after correction of the optical path length, the beam is combined with the return light by the beam splitter 12 and guided to the detection optical system 204 as interference light. The measurement optical system 203 and the reference optical system 202 are arranged so that the interference light guided at that time forms a line image on the line sensor 11. That is, in the reference optical system 202, it is necessary to form a line image at a position where the reference light is conjugate with the fundus of the eye 010 to be examined having a predetermined diopter.

Here, in order to correct the optical path length of the reference light, the reference light is made parallel again by the second cylindrical lens 07, and after correcting the optical path length, the light that forms the line image by the second cylindrical lens 07 is again used. It is necessary to mold the reference beam. As described above, in the reference optical system 202 of the LF-OCT apparatus, the reference light passes through the second cylindrical lens 07 twice on the forward path and the return path. For this reason, the second cylindrical lens 07 is required to have a very high mounting accuracy in adjusting the position and angle with respect to the optical axis.

The present invention has been made in view of the above situation, and provides an LF-OCT apparatus in which the angle of the cylindrical lens arranged in the reference optical system can be easily adjusted.

In order to solve the above problems, an optical coherence tomographic imaging apparatus according to an aspect of the present invention includes:
Splitting means for splitting light from the light source into measurement light and reference light;
First line image generation means arranged in the optical path of the measurement light to generate a first line image of the measurement light;
A second line image generation unit that is arranged in a reference optical system that adjusts the optical path length of the reference light and generates a second line image of the reference light that has the optical path length adjusted;
Interfering means for generating interference light by combining the generated first line image and the second line image on the same imaging plane via an inspection object;
And a tomographic image generation unit configured to generate a tomographic image of the inspection object using the generated interference light.

According to the present invention, in the LF-OCT apparatus, it is easy to adjust the angle and the like with respect to the optical axis of the cylindrical lens arranged in the reference optical system.

It is a figure which shows the optical layout of the line scanning OCT apparatus (LF-OCT apparatus) in Example 1 of this invention. It is a block diagram which shows the function structure in the line scanning OCT apparatus in Example 1 of this invention. It is a figure which shows the optical layout of the line scanning OCT apparatus in Example 2 of this invention. It is a figure which shows the optical layout of the conventional line scanning OCT apparatus.

Hereinafter, exemplary embodiments for carrying out the present invention will be described with reference to the drawings. However, dimensions, materials, shapes, and relative positions of components described in the following embodiments are arbitrary, and can be changed according to the configuration of the apparatus to which the present invention is applied or various conditions. Also, in the drawings, the same reference numerals are used between the drawings to indicate the same or functionally similar elements.

Example 1
An OCT apparatus according to a first embodiment of the present invention will be described with reference to FIGS. In this embodiment, an LF-OCT apparatus in which the reference light passes through the cylindrical lens arranged in the reference optical system once will be described. A simple configuration in which the reference light passes once through the cylindrical lens of the reference optical system makes it easy to adjust the position and rotation at the time of attachment to the optical axis. Furthermore, it can be expected that the accuracy of parts of the cylindrical lens can be lowered by increasing the allowable width in the mounting accuracy. In the following description, the fundus of the eye to be inspected will be described as an example of the object to be inspected by the LF-OCT apparatus.

As described above, the conventional LF-OCT apparatus generates a line image before splitting the light to generate the measurement light and the reference light, and after dividing the line-shaped light into the measurement light and the reference light, Each is led to a measurement optical path and a reference optical path. On the other hand, in the first embodiment (and second embodiment described later), the light from the light source is first divided into reference light and measurement light, and each is individually molded to form a line image, and then virtual The optical members are arranged so as to form line images and interfere with each other on the same imaging plane. By adopting such a configuration, in the present invention, it is easy to adjust the angle and the like with respect to the optical axis of the cylindrical lens disposed in the reference optical system. Details of the first embodiment will be described below.

(Optical configuration)
FIG. 1 schematically shows the optical elements and the like in the OCT optical system 100 in the LF-OCT apparatus according to this embodiment and the layout thereof. The OCT optical system 100 mainly includes a light source 001, a line image generation system 101, a reference optical system 102, a measurement optical system 103, a detection optical system 104, and a beam splitter 012.

The light source 001 is a wavelength swept source (hereinafter referred to as SS) light source, and emits light while sweeping the wavelength at a sweep center wavelength of 1050 nm and a sweep width of 100 nm, for example. The light emitted from the light source 001 is split by the coupler 002 into measurement light and reference light under a desired split ratio. The measurement light and the reference light divided by the coupler 002 are guided to the line image generation system 101 and the reference optical system 102 by optical fibers, respectively.

The line image generation system 101 includes a first collimator lens 013, a first cylindrical lens 003, and a lens 014 that are arranged in order from the exit end of the optical fiber of the measurement light. The measurement light guided to the line image generation system 101 becomes parallel light by the first collimator lens 013, and a line image is formed on the virtual first imaging plane 015 by the first cylindrical lens 003 and the lens 014. Form. The measurement light that is the light that connects the line images passes through the beam splitter 012 and is guided to the measurement optical system 103.

The measurement optical system 103 includes a lens 016, a focus lens 008, a galvanometric mirror 009, and an objective lens unit 017 arranged in order from the beam splitter 012. In this embodiment, the galvanometric mirror 009 is composed of a variable angle mirror disposed at a position substantially conjugate with the anterior eye portion of the eye 010 to be examined. In this embodiment, the objective lens unit 017 is composed of two lenses, guides the measurement light to the eye 010 to be examined, and forms a line image on the fundus.

The focus lens 008 can be moved along the optical axis by a focus driving unit 081 (see FIG. 2) to be described later. It is moved with. Further, the line image of the measurement light guided onto the fundus is scanned on the fundus in a direction different from the extending direction (perpendicular in this embodiment) by changing the angle of the galvanometric mirror 009.

The measurement light reflected and scattered by the fundus of the eye to be examined 010 travels back through the measurement optical system 103 as return light and enters the beam splitter 012 again. The return light is reflected by the beam splitter 012 and guided to the detection optical system 104. At that time, the return light forms a line image on the virtual second imaging plane 018. The second imaging plane 018 in the detection optical system 104 is optically conjugate with the fundus of the eye 010 to be examined and the first imaging plane 015, and is a line arranged via the detection lens group 019. The light receiving surface of the sensor 011 is also conjugate. For this reason, the measurement light reflected and scattered from the line image on the fundus reaches the line sensor 011 as a line image.

The reference light obtained by the coupler 002 is guided to the reference optical system 102 through an optical fiber. The reference optical system 102 includes a second collimator lens 020, an ND filter 005, a mirror unit 021, a reference mirror 006, and a second cylindrical lens 007 arranged in order from the emission end of the optical fiber. The optical fiber is provided with a plurality of polarization adjustment paddles 004 bundled in an annular shape, and a polarization adjustment drive means 041 described later for driving the polarization adjustment paddle 004 is attached thereto. The polarization state of the reference light is changed by adjusting the twist of the annular portion of the polarization adjustment paddle 004 by the polarization adjustment drive unit 041. By providing the polarization adjustment paddle 004 and the like in this manner, the polarization state of the reference light with respect to the polarization state of the measurement light can be adjusted so that the interference state between the measurement light and the reference light is improved.

The reference light that has been polarization-adjusted and is emitted from the exit end of the optical fiber is converted into parallel light by the second collimator lens 020, and further attenuated to a predetermined light amount by passing through the ND filter 005. After attenuation, the reference light reaches the reference mirror 006 through the mirror unit 021. The reference mirror 006 is configured in the form of a retroreflector in the present embodiment, and is movable in the optical axis direction indicated by an arrow in the drawing. By moving the retro reflector in the optical axis direction, the difference between the optical path length of the measurement light and the optical path length of the reference light in the measurement optical system 103 can be corrected.

The reference light returned by the retroreflector is guided to the second cylindrical lens 007 through the mirror unit 021. The second cylindrical lens 007 forms a line image forming lens system with an accompanying lens. The reference light passes through the line image forming lens system and then passes through the beam splitter 012 to form a line image on the second imaging plane 018.

The reference light that has passed through the reference optical system and the return light of the measurement light applied to the fundus are combined by the beam splitter 012, and each line of the reference light and the measurement light (return light) on the second imaging plane 018. The image interferes. The interfering line image is received by the line sensor 011 through the detection lens group 019 in the detection optical system 104. The line sensor 011 detects and outputs an interference signal corresponding to the light reception result. The signal is processed by a signal processing unit 115, which will be described later, and a tomographic image of the fundus is generated.

(Functional configuration)
Next, the LF-OCT apparatus according to the present embodiment will be described with reference to FIG. The LF-OCT apparatus 300 includes the above-described OCT optical system 100, sampling unit 113, memory 114, signal processing unit 115, operation input unit 116, monitor 117, and control unit 118. The control unit 118 is connected to the light source 001 and the line sensor 011 described above, the sampling unit 113, the memory 114, the signal processing unit 115, the operation input unit 116, and the monitor 117.

Further, the control unit 118 is connected to the polarization adjustment drive unit 041, the reflector drive unit 061, the galvano drive unit 091, the focus drive unit 081, and the like arranged in the OCT optical system. As described above, the polarization adjustment driving unit 041 drives the polarization adjustment paddle 004 to adjust the polarization of the reference light. The reflector driving means 061 drives the retro reflector (reference mirror 006) in the optical axis direction to adjust the optical path length of the reference light. The galvano driving means 091 adjusts the angle of the galvanometric mirror 009, thereby scanning the line-shaped measurement light on the fundus. As described above, the focus driving unit 081 moves the focus lens 008 in the optical axis direction to focus the line-shaped measurement light on the fundus. Since these driving means are constructed by a known driving system such as a step motor, description thereof is omitted here.

The light receiving elements in the line sensor 011 composed of a plurality of light receiving elements arranged in a row correspond to the pixels arranged in the extending direction of the line-shaped measurement light on the fundus, for example, on the display screen displaying the fundus image. Therefore, the sampling unit 113 samples the interference signal corresponding to one wavelength sweep of the light source 001 for each pixel corresponding to the measurement light irradiation position designated by the galvano driving unit 091. After sampling of the interference signal accompanying one wavelength sweep, the galvanometric mirror 009 is driven to move the measurement light irradiation position by one pixel in a direction perpendicular to the extending direction of the line-shaped measurement light, The interference signal is sampled again at the position. Thereafter, by repeating this, for example, interference signals corresponding to each pixel on the display screen of the monitor 117 are sampled one after another.

The interference signal sampled by the sampling unit 113 is stored in the memory 114 in association with the drive position of the galvanometric mirror 009. The interference signal stored in the memory 114 is subjected to frequency analysis by the signal processing unit 115, and tomographic image data in the depth direction is generated for each pixel. These tomographic image data are combined to generate a three-dimensional tomographic image of the fundus of the eye 010 to be inspected, and an image corresponding to an instruction from the operator is constructed and displayed on the monitor 117. 3D tomographic image display, display of a tomographic image along an arbitrary cutting line, indication of an image to be displayed such as a plane image generated based on 3D tomographic image data, or change of sampling conditions, for example, GUI And an operation input unit 116 including a keyboard, a mouse, and the like. The control unit 118 displays an image generated according to the input instruction on the monitor 117 as a display unit as a display control unit.

The control unit 118 can be configured using a general-purpose computer, but may be configured from a dedicated computer. In addition, although the monitor 117 is illustrated as a separate body from the control unit 118, these may be a single configuration. That is, some or all of the configurations shown as separate bodies in FIG. 2 may be integrally formed. Moreover, although each structure is connected by wire, it is good also as connecting this part or all by radio | wireless.

As described above, in the present embodiment, the light emitted from the light source 001 is first divided into the reference light and the measurement light before being formed into a line shape, and the measurement light is transmitted to the eye 010 to be examined through the measurement optical path. Before arriving, the reference light is formed into a line after the adjustment of the reference optical path length. By adopting such an aspect, the reference light can pass through the second cylindrical lens 007 disposed in the reference optical system 102 so that the reference light passes only once. For this reason, the component accuracy required for the second cylindrical lens 007, and the position and rotation accuracy with respect to the optical axis at the time of attachment can be lowered. Therefore, when the apparatus is actually constructed, adjustment at the time of mounting the second cylindrical lens 007 is facilitated.

Also, in order to obtain an interference signal, it is desirable to match the polarization state of the return light and the reference light that has passed through the reference optical system. In this case, it is desirable to adjust the polarization state of the reference light separately from the measurement light or the return light. According to this embodiment, the polarization adjustment paddle 004 is provided before the reference light is converted into spatial light in the reference optical system 102. For this reason, it is possible to adjust the polarization independently of the measuring light without arranging a large number of wave plates and adjusting the angle of each of them. Therefore, for example, as in the OCT apparatus disclosed in Non-Patent Document 1, the optical path of the reference light is separated by the forward path and the return path, and compared with the case where the wave plate is disposed on either of them, the polarization can be achieved with a simple configuration. Adjustments can be made. As a result, an appropriate interference state between the measurement light and the reference light can be easily obtained, and a good tomographic image can be obtained. Also, the polarization adjustment of the measurement light and the reference light can be performed individually and easily.

In this embodiment, the light from the light source 001 is split into measurement light and reference light by a coupler 002 which is an example of a splitting unit. A first cylindrical lens 003, which is an example of a first line image generation unit, is disposed in the optical path of the measurement light and generates a first line image of the measurement light on the first imaging plane 015. The second cylindrical lens 007 as an example of the second line image generation unit is disposed in the reference optical system 102 that adjusts the optical path length of the reference light, and the reference light passes through the reference mirror 006 and is the reference optical path length. The second line image is generated by the reference light after the adjustment of. These cylindrical lenses are an example of a line image generating means, and can be replaced by another optical member having the same function as long as a similar line image is obtained.

The first line image and the second line image generated via the fundus of the eye to be examined are formed on the second imaging plane 018 which is the same imaging plane by the beam splitter 012 which is an example of an interference unit. The light is combined as a line image to generate interference light. The sampling unit 113, the signal processing unit 115, the control unit 118, and the like constitute tomographic image generation means for generating a tomographic image of the fundus using the interference light generated as described above. With these configurations, the optical coherence tomography apparatus (LF-OCT apparatus) shown in the present embodiment is constructed. The beam splitter 012 is an example of an interference means for combining and interfering the first line image and the second line image on the same imaging plane, and connects the two line images on the same imaging plane. If it is possible to make the image interfere, it can be replaced by a known optical member. Further, the arrangement in the reflection direction and the transmission direction with respect to the beam splitter 012 of the measurement optical system 103 and the reference optical system 102 may be opposite to that in the embodiment.

Here, in the LF-OCT apparatus, a first collimator lens 013 is disposed as an example of first collimating means that uses the measurement light guided to the first line image generating means as parallel light. . In addition, a second collimator lens 020 is disposed as an example of second collimating means that collimates the reference light guided from the coupler 002 and emitted to the reference optical system 102. Then, the first cylindrical lens 003 and the second cylindrical lens 007 respectively generate a first line image and a second line image from parallel light. These collimator lenses are examples of collimating means, and can be replaced by optical members having the same function as long as similar parallel light is obtained.

As described above, the present embodiment includes the coupler 002 as the dividing means, and the reference light is guided from the coupler 002 to the reference optical system 102 via the optical fiber. At this time, the optical fiber is bundled as a plurality of annular shapes, and the polarization of the reference light is adjusted by being driven, for example, by adjusting the twist of the annular portion. The annular portion of the optical fiber functions as an example of a polarization adjustment unit by the polarization adjustment drive unit 041 that drives the optical fiber. The reference light is combined with the return light of the measurement light that has passed through the eye to be examined 010. In order to obtain a suitable interference state at that time, it is desirable that the polarization of the return light and the reference light match. In the present embodiment, the polarization of the reference light can be adjusted easily and appropriately by arranging the polarization adjusting unit at a position where the polarization adjustment is performed before the reference light is formed into a line shape or the like.

(Example 2)
Next, an LF-OCT apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. In the first embodiment described above, the light emitted from the light source 001 is guided to the coupler 002 by the optical fiber, and the reference light and the measurement light are also guided from the coupler 002 to the reference optical system 102 and the measurement optical system 103, respectively. ing. On the other hand, in the second embodiment, the light from the light source 001 is divided as spatial light and guided to the corresponding optical system. In FIG. 3, the same reference numerals are used for the same components as those in the first embodiment, and the description thereof is omitted here.

Hereinafter, specific differences from the first embodiment will be described. In the first embodiment, the light emitted from the light source 001 is split into measurement light and reference light by the coupler 002. However, in the second embodiment, the light emitted from the light source 001 is converted into parallel light by the light source unit collimator lens 022 and divided into measurement light and reference light by the beam splitter 023. The split ratio by the beam splitter 023 is set to a desired value similar to that of the coupler 002. In the following, the light reflected by the beam splitter 023 is used as measurement light, and the transmitted light is used as reference light. Conversely, the reflected light may be used as reference light and the transmitted light may be used as measurement light.

In this embodiment, the light split by the reflection by the beam splitter 012 in the parallel light is used as measurement light. The measurement light is guided to the line image generation system 101 ′, and a line image is formed on the first imaging plane 015 by the first cylindrical lens 003 and the lens 014 arranged in the same manner as in the first embodiment. To do. The measurement light in the form of a line passes through the beam splitter 012 and is guided to the measurement optical system 103. The measurement optical system 103 has the same configuration as that of the first embodiment.

On the other hand, the light divided by the transmission by the beam splitter 012 in the parallel light is used as reference light. The reference light is guided to the reference optical system 102 ′ by the mirror 024. The reference optical system 102 ′ is provided with a polarization adjusting unit 025 including a plurality of wave plates, and the reference light guided to the reference optical system 102 ′ by the mirror 024 is subjected to polarization adjustment by the polarization adjusting unit 025. The After the change adjustment, the reference light is guided to the ND filter 005 by the mirror 026. The configuration arranged after the ND filter 005 is the same as that of the reference optical system 102 in the first embodiment.

The return light that has passed through the fundus by the measurement optical system 103 and the reference light that has passed through the reference optical system 102 ′ are combined on the second imaging plane 018 in the same manner as in the first embodiment, and an interfering line image is obtained. Generate. The interfering line image is received by the line sensor 011 and the line sensor 011 outputs a signal corresponding to the light reception result. Thereafter, similarly to the first embodiment, a tomographic image of the fundus of the eye 010 to be examined can be obtained using the components shown in the block diagram of FIG.

For example, when the light shaped into a line is divided into reference light and measurement light, and then the polarization of the reference light is adjusted, the polarization adjusting means is arranged in the reference optical system. In this case, similarly to the second cylindrical lens, the reference light passes through the outgoing path and the return path twice also in the polarization adjusting means, so that high mounting accuracy is required. Here, since it is not easy to appropriately adjust the polarization in the state of passing twice, the optical path is actually made different between the forward path and the return path, and the mode of passing only once in either the forward path or the return path is used. Possible correspondence. In this embodiment, the polarization adjusting unit 025 allows the reference light to pass through when it is guided to the reference optical system 102 '. Accordingly, there is no need to pay attention to such an optical path, and such an arrangement problem does not occur.

In the present embodiment, the dividing means includes a beam splitter 023. The reference optical system 102 ′ includes a polarization adjusting unit 025 that is disposed between the beam splitter 023 and the second cylindrical lens 007 and adjusts the polarization of the reference light. In the present embodiment, the polarization adjusting unit 025 is disposed at a position where the reference light passes through the reference optical system 102 'at the beginning. However, it can be arranged at any position on the optical path of the reference light in the reference optical system 102 ′ and between the beam splitter 023 and the second cylindrical lens 007.

In the embodiment described above, the first line image generating means is constituted by a cylindrical lens, and the cylindrical lens can be defined as a first line image forming lens having different curvatures in two orthogonal meridian directions. Similarly, the second line image generating means is also composed of a cylindrical lens, and the cylindrical lens can be defined as a second line image forming lens having different curvatures in two orthogonal meridian directions. Note that the line image generation means is not limited to one configured from a single cylindrical lens, and may be any apparatus that has at least one cylindrical lens and forms a line image.

In the above-described first and second embodiments, the description has been given by taking as an example an apparatus for capturing or measuring a fundus tomographic image and a three-dimensional tomographic image. However, the inspection object to be inspected is not limited to the fundus of the eye to be examined, and may be, for example, the anterior eye portion of the eye to be examined. It is obvious that the effect of the present invention can be obtained even if the present invention is applied to an apparatus that captures or measures the tomographic image and three-dimensional tomographic image of the anterior segment. In addition, the present invention can be applied to skins and organs other than the eyes as the object to be inspected. In this case, the present invention has an aspect as an optical coherence tomography apparatus that captures an image based on data obtained from a medical device such as an endoscope.

Further, in the above-described Example 1 and Example 2, a wavelength sweep type (SS) light source is used as the light source, and the light from the light source is formed into a line shape, projected onto the eye to be examined, and reflected and scattered by the eye to be examined. The light and the line-shaped reference light are made to interfere. The line sensor obtains an interference signal from the interference light, and performs signal processing on the interference signal to obtain a tomographic image of the eye to be examined. However, the mode of the light source is not limited to this, and a super luminescence diode (SLD) that emits light in a wavelength region of about 50 nm to 100 nm may be used as the light source. In this case, the line-shaped interference light is wavelength-resolved by a spectroscope, the separated interference light is detected for each wavelength by a two-dimensional area sensor as a detector, and signal processing is performed to obtain a tomographic image and a three-dimensional tomogram of the eye to be examined. An image can be acquired.

The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above-described embodiments. For example, the mirror or mirror unit should be changed as appropriate in view of the space allowed for the optical system. In other words, the present invention includes inventions modified within the scope not departing from the spirit of the present invention and inventions equivalent to the present invention. Moreover, each Example mentioned above can be combined suitably in the range which is not contrary to the meaning of this invention.

This application claims the priority of Japanese Patent Application No. 2017-091421 filed on May 1, 2017, the contents of which are incorporated herein by reference.

001: Light source, 002: Coupler, 003: First cylindrical lens, 007: Second cylindrical lens, 012: Beam splitter, 013: Collimator lens, 020: Second collimator lens

Claims

Splitting means for splitting light from the light source into measurement light and reference light;
First line image generation means arranged in the optical path of the measurement light to generate a first line image of the measurement light;
A second line image generation unit that is arranged in a reference optical system that adjusts the optical path length of the reference light and generates a second line image of the reference light that has the optical path length adjusted;
Interfering means for generating interference light by combining the generated first line image and the second line image on the same imaging plane via an inspection object;
An optical coherence tomographic imaging apparatus comprising: a tomographic image generation unit configured to generate a tomographic image of the inspection object using the generated interference light.
First collimating means for collimating the measurement light guided to the first line image generating means;
Second collimating means for making the reference light guided from the dividing means and emitted to the reference optical system into parallel light,
The first line image generation means generates the first line image from the measurement light converted into parallel light by the first collimation means, and the second line image generation means is the second collimation means. 2. The optical coherence tomographic imaging apparatus according to claim 1, wherein the second line image is generated from the reference light that has been converted into parallel light.
The optical coherence tomographic imaging apparatus according to claim 1 or 2, wherein the dividing means includes a coupler.
The reference light is guided from the coupler to the reference optical system via an optical fiber,
The optical coherence tomography apparatus according to claim 3, wherein the optical fiber includes a polarization adjustment unit that adjusts polarization of the reference light by driving the optical fibers bundled as a plurality of rings.
3. The optical coherence tomography apparatus according to claim 1, wherein the dividing unit includes a beam splitter.
The light according to claim 5, wherein the reference optical system includes a polarization adjusting unit that is disposed between the beam splitter and the second line image generating unit and adjusts the polarization of the reference light. Coherent tomography device.
The optical interference according to any one of claims 1 to 6, wherein the first line image generation means includes at least a first line image forming lens having different curvatures in two orthogonal meridian directions. Tomographic imaging device.
The optical interference according to any one of claims 1 to 7, wherein the second line image generation means includes at least a second line image forming lens having different curvatures in two orthogonal meridian directions. Tomographic imaging device.
9. The optical coherence tomographic imaging apparatus according to claim 1, wherein the object to be inspected is an eye.
The light source is a wavelength sweep type light source,
The optical coherence tomographic imaging apparatus according to claim 1, wherein the tomographic image generation unit includes a line sensor that detects an interference signal from the interference light.