JP2019072027A - Ophthalmologic apparatus and focus unit - Google Patents

Abstract

To provide an ophthalmologic apparatus and a focus unit that reduce an influence of a ghost by a corneal reflection light in receiving a return light from the ocular fundus of an eye to be examined irradiated with a line-like measurement light.SOLUTION: An ophthalmologic apparatus includes: an irradiation optical system for irradiating the ocular fundus of an eye to be examined with a line-like measurement light; an image forming optical system for forming an image with a corneal reflection light from the cornea of the eye to be examined; a reduction member 007 disposed at a position where an image is formed with the corneal reflection light for reducing the corneal reflection light with which an image is formed from a return light from the ocular fundus irradiated with the line-like measurement light; and a light reception optical system for receiving the return light in which the corneal reflection light is reduced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ophthalmologic apparatus and a focus unit used in the ophthalmologic apparatus.

  In recent years, in the field of ophthalmology, an apparatus (hereinafter referred to as an OCT apparatus) that performs optical coherence tomography (OCT) capable of noninvasively observing / examining a tomogram of the fundus and the anterior segment has become widespread. In OCT, low coherent light (measurement light) is irradiated to the subject's eye, and information on the tomographic image of the subject's eye is obtained using interference light obtained by combining the return light from the subject's eye and the reference light. There is. Further, by scanning this measurement light in a predetermined range on, for example, the fundus of the eye to be examined, three-dimensional tomographic information in the predetermined range can be obtained. An OCT apparatus embodying the method is widely used in medicine from research to clinic.

  OCT is roughly classified into two types, time domain OCT and Fourier domain OCT. Furthermore, Fourier domain OCT includes spectral domain OCT (SD-OCT) and swept source OCT (SS-OCT). In these Fourier domain OCT, interference light obtained from the subject's eye is dispersed to obtain an interference signal, and the obtained interference signal is subjected to signal processing such as Fourier transform to obtain information on a tomographic image of the subject's eye. In SD-OCT using wide wavelength band light, the interference light is spatially separated by a spectroscope to obtain information for each frequency. In SS-OCT using light from a wavelength sweeping type light source, interference light obtained from light from a light source emitting light of a wavelength different temporally is temporally dispersed to obtain information for each frequency.

  Currently, in an ophthalmologic apparatus that scans light on the fundus to obtain information on the fundus, the light is shaped into a line and irradiated onto the fundus, and the examination time is shortened by scanning the fundus with the line-shaped light Is planned. Patent Document 1 discloses a scanning laser ophthalmoscope (SLO) that irradiates a subject with light shaped into a line. Further, Non-Patent Document 1 discloses a line scanning type OCT apparatus using a Michelson type interference system.

  In a conventional line scanning type OCT apparatus, light emitted from a wavelength sweeping type light source is linearly shaped at a position conjugate with the fundus using a cylindrical lens or the like. The light beam shaped in the form of a line is divided into measurement light and reference light, and the measurement light is guided to the fundus of the eye to be examined and scanned over the fundus. The measurement light reflected and scattered by the fundus and returned from the fundus is combined with the reference light that has passed through the reference optical path, whereby a line of interference light is obtained. By receiving the interference light by the line sensor, an interference signal for obtaining information of the tomographic of the fundus can be obtained.

JP 2017-46939

DJ Fechtig, B. Grajciar, T. Schmoll, C. Blatter, RM Werkmeister, W. Drexler, and R. a Leitgeb, “Line-field parallel swept source MHz OCT for structural and functional retinal imaging.,” Biomed. Opt. Express, vol. 6, no. 3, pp. 716-35, Mar. 2015.

  Here, in the conventional line scan type ophthalmologic apparatus such as the conventional line scan type SLO apparatus and the conventional line scan type OCT apparatus, the reflected light of the linear measurement light having the cornea as the reflection surface (hereinafter, the cornea for simplification) It is noted that it is reflected light. At this time, in the line scanning type ophthalmologic apparatus, the line sensor receives the line-like return light from the fundus of the subject's eye irradiated with the line-like measurement light. For this reason, the corneal reflection light included in the return light from the subject's eye is received as a so-called ghost in the line sensor. Such ghost light reception may cause problems such as deterioration of the image quality of the fundus image (front image of the fundus, tomographic image of the fundus, etc.) or failure to obtain fundus information of a portion overlapping with the ghost.

  One of the objects of the present invention is to solve the above-mentioned problems, and an ophthalmologic apparatus for receiving return light from the fundus of an eye to be examined to which line-like measurement light has been irradiated, comprising: To reduce the impact.

In order to solve the above-mentioned subject, the ophthalmologic apparatus concerning one mode of the present invention is:
An irradiation optical system for irradiating the fundus of the subject's eye with a linear measurement light;
An imaging optical system for imaging corneal reflected light from a cornea of the subject's eye;
A reducing member disposed at a position where the corneal reflected light is imaged, and reducing the imaged corneal reflected light from the return light from the fundus irradiated with the linear measurement light;
A light receiving optical system that receives the return light from which the corneal reflection light has been reduced;
And the like.

  According to one of the aspects of the present invention, in the ophthalmologic apparatus that receives the return light from the fundus of the subject's eye irradiated with the linear measurement light, it is possible to reduce the influence of the ghost due to the corneal reflection light.

It is a figure which shows typically the optical system layout in the line scanning type OCT apparatus which is the 1st Example of this invention. It is a block diagram which shows the function structure in the line scanning OCT apparatus in a 1st Example. It is a figure which shows typically the optical system layout in the line scanning type OCT apparatus which is the 2nd Example of this invention.

  Hereinafter, exemplary embodiments for carrying out the present invention will be described with reference to the drawings. However, the dimensions, materials, shapes, relative positions of components, etc. 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, like reference numerals are used to indicate identical or functionally similar elements.

First Embodiment
Hereinafter, with reference to FIGS. 1 and 2, a line scanning OCT apparatus (hereinafter referred to as an L-OCT apparatus) according to a first embodiment of the present invention will be described. FIG. 1 is a view schematically showing an optical system layout in the L-OCT apparatus in the present embodiment, and FIG. 2 is a block diagram showing a functional configuration in the L-OCT apparatus in the present embodiment.

(Optical system layout)
The L-OCT apparatus in the present embodiment includes an objective lens 001, a galvanometric mirror 002, a convex lens 003, a focusing unit 100, a line image forming optical system 101, and a reference optical system 102. In addition, a beam splitter 012, an imaging lens 013, and a line sensor 014 are provided. The objective lens 001 is disposed on the optical axis L1 to face the eye E. The galvanometric mirror 002 is disposed at a position substantially conjugate with the anterior segment of the eye E with respect to the objective lens 001. A convex lens 003, a focus unit 100, a line image forming optical system 101, a collimator lens 009, and an optical fiber end 010 for emitting sample light are on the optical axis L2 which is the reflection direction of the galvanometric mirror 002 and orthogonal to the optical axis L1. It is arranged.

  The focusing unit 100 includes a concave lens 004, an intra-unit beam splitter 005, a convex lens 006, a perforated mirror 007, and a convex lens 008. The concave lens 004 functions as a substantial focusing lens in the focusing unit 100. In this embodiment, a line image forming optical system 101, an intra-unit beam splitter 005, a concave lens 004, a convex lens 003, and a galvanometric mirror 002 described later are disposed on the optical axis L2. A convex lens 006 and a perforated mirror 007 are disposed on the optical axis L3 in the reflection direction of the intra-unit beam splitter 005, and a convex lens 008 is disposed on the optical axis L4 in the reflection direction of the perforated mirror 007 There is.

  The focusing unit 100 is integrated with the above-described optical members in the focusing unit 100, and is moved in the direction of the optical axis L2 in accordance with the diopter of the eye E by the focusing unit driving unit 1001 described later. Further, the optical axis L2 and the optical axis L4 are disposed in parallel with each other. In addition, it is preferable that the hole part of the holed mirror 007 mentioned above is a rectangular shape corresponding to the line image mentioned later, for example. However, depending on the removal efficiency of the corneal reflection light and the configuration of the other optical members, the shape may be other than rectangular.

  In the line image forming optical system 101, for example, light (hereinafter referred to as measurement light) obtained by dividing light emitted from a wavelength sweep type low coherent light source (see SS light source 021 in FIG. 2) corresponding to a wide band. Led. Specifically, light emitted from the light source is split by a coupler (not shown), and the obtained measurement light is drawn by, for example, an optical fiber (not shown) and emitted from the optical fiber end 010 onto the optical axis L2. The measurement light emitted from the optical fiber end 010 is collimated by the collimator lens 009 and guided to the line imaging optical system 101 as spatial light.

  The line image forming optical system 101 includes a cylindrical lens, a spherical lens, and the like (not shown). With these configurations, the line image forming optical system 101 forms a line image on the fundus oculi Ef with the measurement light incident on the eye E via the focus unit 100, the convex lens 003, the galvanometric mirror 002, and the objective lens 001. Do. That is, the measurement light line-shaped by the line image forming optical system 101 is irradiated onto the fundus oculi Ef. The line image forming optical system 101 may be provided with a light flux limiting unit having a rectangular opening that acts on the length and the width of the line image. In addition, the size of the mirror portion in the direction perpendicular to the paper surface of the galvanometric mirror 002 may have a substantial aperture diameter that determines the length of linear light irradiated to the fundus oculi Ef of the eye to be examined E.

  A beam splitter 012, an imaging lens 013, and a line sensor 014 are disposed on the optical axis L4 of the light emitted from the focusing unit 100. The objective lens 001, the galvanometric mirror 002, the convex lens 003, the focusing unit 100, the beam splitter 012 and the imaging lens 013 from the eye E to the line sensor 014 constitute a sample optical system in this embodiment.

  A reference optical system 102 is disposed on an optical axis L5 orthogonal to the optical axis L4 of the beam splitter 012. Light (hereinafter referred to as reference light) obtained by dividing the light emitted from the above-described low coherent light source is guided to the reference optical system 102. Specifically, the reference light obtained by splitting from the light emitted from the light source by the above-mentioned coupler (not shown) is, for example, drawn by an optical fiber (not shown) and emitted from the optical fiber end 016 onto the optical axis L5. The reference light emitted from the optical fiber end 016 is collimated by the collimator lens 015 and guided to the reference optical system 102 as spatial light.

  Like the line image forming optical system 101, the reference optical system 102 includes a cylindrical lens, a spherical lens, and the like (not shown). With these configurations, the reference optical system 102 shapes the reference light into a line, and can interfere with the measurement light guided to the line sensor 014 through the sample optical system. The reference optical system 102 also has a function of adjusting the optical path length of the reference light reaching the beam splitter 012. Specifically, for example, a reference mirror or the like is disposed in the reference optical system 102, and a path in which the reference light reciprocates via the reference mirror or the like is provided. The optical path length of the reference light is adjusted by moving the reference mirror on the optical axis by the reference mirror driving means 1003 described later.

  The reference light emitted to the beam splitter 012 is reflected along the optical axis L4. The reflected reference light is multiplexed with the measurement light incident on the beam splitter 012 along the optical axis L4, and forms a line image on the line sensor 014 by the imaging lens 013 as interference light. The line sensor 014 is configured by arranging a plurality of pixels corresponding to each position of the line image formed on the fundus, and outputs a signal corresponding to the interference light from each pixel. Further, the galvanometric mirror 002 can change the angle of the reflection surface with respect to the optical axis L2 by the galvano driving means 1002 described later. The fundus oculi Ef can be two-dimensionally illuminated by scanning the linear measurement light irradiated onto the fundus oculi Ef in the direction orthogonal to the longitudinal direction of the measurement light by the galvanometric mirror 002.

  Here, the sample optical system including the focusing unit 100 will be described in detail. As described above, the corneal reflection light described below refers to reflection light with the cornea of the line image emitted from the galvanometric mirror 002 as a reflection surface.

(Removal of corneal reflection light)
As described above, the galvanometric mirror 002 is disposed at a position substantially conjugate with the objective lens 001 and the anterior segment of the eye E. For this reason, the corneal reflected light of the eye cornea Ec of the line image is imaged by the objective lens 001 in the vicinity of the galvanometric mirror 002. The convex lens 003 is disposed such that the front focal point substantially coincides with the position of the galvanometric mirror 002, more specifically, the turning center in the turning operation. Therefore, the corneal reflected light formed in the vicinity of the galvanometric mirror 002 passes through the convex lens 003 and is incident on the focusing unit 100 as parallel light. The corneal reflected light that has entered the focusing unit 100 forms an image in the hole of the perforated mirror 007 by the concave lens 004 and the convex lens 006.

  In this embodiment, during the imaging, the corneal reflection light is reflected from the optical axis L1 along the optical axis L3 by the intra-unit beam splitter 005 disposed between the concave lens 004 and the convex lens 006, and the measurement light is It branches from the incident path made incident on the optometry E. Although the perforated mirror 007 reflects the light through the convex lens 006 in the direction of the optical axis L4, most of the corneal reflection light formed on the hole of the perforated mirror 007 passes through the hole and thereby the optical axis It is almost unguided in the L4 direction. Therefore, in the present embodiment, the corneal reflection light included in the return light received by the line sensor 014 is reduced. Therefore, unnecessary corneal reflection light that degrades the image quality can be substantially removed for line scanning OCT, and clear tomograms can be obtained. In this embodiment, the purpose is to prevent or reduce most of the above-mentioned corneal reflected light from being received by the line sensor 014, and the corneal reflection from the light beam including the return light from the fundus and the corneal reflected light This is achieved by removing most of the light. The removal of most of the corneal reflection light from the return light reaching the line sensor 014 is referred to as removal or reduction in the following description.

  When obtaining a tomogram, it is usually necessary to move the focus lens on the optical axis according to the diopter of the eye E to focus the measurement light on the fundus. In the present embodiment, the concave lens 004 functioning as the focusing means moves integrally with other optical members as the focusing unit 100 and moves on the optical axis L2. At this time, when the alignment between the OCT apparatus and the eye E is completed, the focus unit 100 moves in the optical axis direction on the optical axis L2 according to the diopter of the eye E to focus the measurement light You need to do the operation. However, even if such movement of the focus unit 100 is performed, the state in which the corneal reflection light enters the focus unit 100 as parallel light does not change. For this reason, since the corneal reflection light forms an image in the hole of the perforated mirror 007 regardless of the diopter of the eye E, the corneal reflection light can be removed regardless of the eye.

  In the present embodiment, for the removal of the corneal reflection light, the perforated mirror 007 provided with the hole on the optical axis L3 is used. By using the perforated mirror 007, it is possible to efficiently guide the return light in which the proportion of the corneal reflection light is reduced to the line sensor 014. In addition, since the shape of the hole is the reflected light of the linear light, it is preferable to form a rectangular slit so as to correspond to this shape. As a result, it is possible to minimize the loss of light quantity of the return light accompanying the removal of the corneal reflection light, and to obtain a tomogram efficiently. However, the shape of the hole is not limited to this, and various modifications can be made in combination with other configurations so as to be able to remove the corneal reflected light more reliably, and the mirror shape used for removing the corneal reflected light is not limited to this. . For example, the perforated mirror 007 illustrated in FIG. 1 may be replaced by a rectangular mirror which is decentered upward or downward with respect to the optical axis L3.

(Align focus)
Next, focusing operation of the measurement light using the focus unit 100 in the present embodiment will be described. When the diopter of the eye to be examined E is 0 diopter (appended as 0D in FIG. 1), the return light from the fundus oculi Ef of the linear measurement light irradiated to the fundus oculi Ef is the fundus oculi Ef when the diopter is 0D. Image on a virtual plane f0 which is a conjugate plane of The return light reflected in the direction of the optical axis L2 by the galvanometric mirror 002 becomes parallel light by the convex lens 003 and the concave lens 004 and enters the intra-unit beam splitter 005. At this time, in the focusing unit 100, the central position of the intra-unit beam splitter 005 is disposed at a position corresponding to 0D on the optical axis L2. The return light on the optical axis L2 is reflected in the direction of the optical axis L3 by the intra-unit beam splitter 005, and is imaged on the virtual plane f0 'by the convex lens 006. After imaging, the return light is reflected by the perforated mirror 007 in the direction of the optical axis L 4, and enters the convex lens 008. The return light becomes parallel light by the convex lens 008 arranged so that the front focal plane coincides with the virtual plane f 0 ′, and the focus unit 100 is emitted. The return light emitted from the focusing unit 100 is combined with the reference light by the beam splitter 012 as described above, and is imaged on the line sensor 014 by the imaging lens 013.

  Next, the case where the diopter of the eye to be examined E is other than 0D will be described. At this time, the conjugate plane of the fundus oculi Ef forms a fundus conjugate plane at a position different from the above-described virtual plane f0, for example, at a position shown as -D or + D across the virtual plane f0 in FIG. In this case, according to the diopter of the subject's eye, the focus unit 100 is an arrow between -D and + D centered on 0D in the figure along the optical axis L2 (and the optical axis L4 parallel to the optical axis L2). The measurement light is moved in the direction of the optical axis shown to focus the measurement light on the fundus oculi Ef. At this time, in the present embodiment, the light beam reflected or the like from the fundus by the convex lens 003 and the concave lens 004 is collimated light. Thus, the light beam reflected by the intra-unit beam splitter 005 is guided in the same direction toward the perforated mirror 007 regardless of the diopter of the eye E. That is, even when the diopter of the eye to be examined E is other than 0D, this luminous flux forms an image on the virtual plane f 0 ′ in the focusing unit 100. Therefore, even in this case, the light beam is collimated by the convex lens 008 after being reflected by the perforated mirror 007, and is imaged on the line sensor 014 after the focusing unit 100 is emitted.

  As described above, in this embodiment, the return light is disposed so that the incident optical axis (optical axis L2) to the focusing unit 100 and the outgoing optical axis (optical axis L4) are parallel, and the optical axis at the time of focusing The focus unit 100 is moved in the optical axis direction of L2 and L4. Therefore, even if the focusing operation according to the diopter of the eye to be examined E is performed, the optical path length of the measurement light can be kept constant. In the OCT apparatus, when obtaining a tomogram of the eye to be examined, it is necessary to adjust each optical path length so that the optical path length of the measurement light and the optical path length of the reference light become the same. According to this embodiment, the optical path length of the measurement light does not change even when the focusing operation is performed, so that it is not necessary to frequently change the optical path length of the reference light according to the diopter of the subject's eye .

(Functional configuration)
Next, with reference to FIG. 2, a control system of the L-OCT apparatus in the present embodiment including the above-described focus unit 100 will be described. As shown in FIG. 2, the L-OCT apparatus used in the present embodiment has a sampling unit 022, a memory 023, a signal processing unit 024, a control unit 020, a monitor 025, and an operation input unit 026 as a control unit. The sampling unit 022, the memory 023, the signal processing unit 024, the monitor 025, and the operation input unit 026 are connected to the control unit 020 and controlled by the control unit 020. Note that the control unit 020 and a part of the configuration connected thereto may be configured using a general-purpose computer, or may be configured using a computer dedicated to the L-OCT apparatus. Also, the monitor 025 may be configured using any monitor. Similarly, the operation input means 026 may be configured using any input device such as a known keyboard and mouse. Further, in the present embodiment, the OCT optical system, the control unit 020, the monitor 025, and the like are separately configured, but some or all of them may be integrally configured.

  The memory 023 stores a tomogram to be described later generated by the signal processing means 024, various data used for alignment of the tomograms, information of the inputted subject, a program constituting the signal processing means 024, etc. Do. The control means 020 controls the monitor 025 which is a display unit as a display control unit, and causes the monitor 025 to display various images stored in the memory 023, information of the subject, and the like. Each component of the signal processing means 024 can be configured by a module executed by the CPU or MPU of the signal processing means 024. Also, each component of the signal processing means 024 may be configured by a circuit or the like that implements a specific function such as an ASIC. The memory 023 can be configured using any storage device / storage medium such as a memory or an optical disk.

  The OCT optical system further includes a focus unit drive unit 1001 for driving and controlling the above-described optical member, a galvano drive unit 1002, and a reference mirror drive unit 1003. The focus unit drive unit 1001 moves the focus unit 100 in the direction of the optical axis L2 (and L4), and adjusts the in-focus state of the measurement light with respect to the fundus oculi Ef of the eye to be examined E. The galvano driving unit 1002 drives and controls the galvanometric mirror 002 to control the irradiation position and the like of the linear measurement light on the fundus oculi Ef. The reference mirror driving unit 1003 moves the reference mirror (not shown) in the optical axis direction in the reference optical system 102 as described above, and adjusts the difference in optical path length between the measurement light and the reference light.

  The focus unit driving unit 1001, the galvano driving unit 1002, and the reference mirror driving unit 1003 are connected to the control unit 020. In addition, the optical system of the L-OCT apparatus described above is enclosed in one case and integrated, and the eye E to be examined and the OCT optical system are connected via the alignment driving means 1005 connected to the control means 020. Alignment is performed. The SS light source 021 for emitting light that is the source of the measurement light and the reference light is connected to the control means 020, and the control means 020 controls the emission of the light source light and the like. In the present embodiment, although a wavelength sweeping light source for sweeping the wavelength of the emission light in a wide band is used, a low coherent light source for emitting light in a wide band may be used. The control means 020 drives and controls each component of the OCT optical system through the configuration described above.

  The line sensor 014 in the OCT optical system is connected to the control means 020 via the sampling unit 022. The output signal of the line sensor 014 is sampled by the sampling unit 022 as an interference signal. The sampled interference signal is sent to the signal processing means 024 via the control means 020 and subjected to various signal processing such as Fourier change to generate an image such as a tomographic image. The generated image is displayed by the monitor 025, and the display format and the instruction to control the drive of the OCT optical system are given by the user via the operation input unit 026.

(Imaging method)
In the L-OCT apparatus described above, scan control of measurement light described below is performed when scanning the fundus with measurement light at the time of acquisition of an interference signal for generating a tomographic image. That is, an output signal from the line sensor 014 is obtained according to the drive angle of the galvanometric mirror 002 driven by the galvano drive unit 1002. The acquired output signal is received corresponding to one wavelength sweep of the SS light source 021 for each pixel of the line sensor 014, and one interference including information on the depth direction of the position on the fundus corresponding to the pixel It becomes a signal. Therefore, as the line sensor 014, an interference signal capable of generating one tomographic image corresponding to a line image can be obtained by one wavelength sweep.

  Then, also at the next drive angle of the galvanometric mirror 002, the output signal for the next interference signal is similarly received by the line sensor 014 that has received this light corresponding to the next wavelength sweep of the SS light source 021 for each pixel. Is obtained. Thereafter, groups of interference signals capable of generating tomographic images corresponding to individual drive angles are sequentially acquired in this repetition. The interference signal generated from the output signal by the sampling unit 022 is stored in the memory 023 together with information on the drive angle of the galvanometric mirror 002. The interference signal stored in the memory 023 is subjected to frequency analysis by the signal processing means 024, and displayed on the monitor 025 as a cross-sectional image of the fundus oculi Ef of the eye to be examined E or a three-dimensional fundus volume image.

  Also, the control unit 020 acquires background data at an arbitrary timing during imaging. Background data refers to a signal in a state where measurement light does not enter the eye to be examined E, that is, a signal obtained only from the reference light. The background data is obtained, for example, by driving the galvanometric mirror 002 by the galvano driving unit 1002 and performing signal acquisition in a state in which the scanning position of the measurement light is adjusted so that the measurement light does not return from the sample optical system. By subtracting this background data from the interference signal or the data after frequency analysis, a tomographic image of the fundus oculi Ef more in line with the actual state can be obtained.

  In the focus unit 100 in the embodiment described above, the optical axis L2 and the optical axis L4 are disposed in parallel. In addition, when the diopter of the eye to be examined E changes, the focus unit 100 is moved along the optical axis L2 to cope with this. Further, by setting the focusing unit 100 to the configuration described in the present embodiment, an effect is obtained that the removal efficiency of the corneal reflection image does not largely change due to the diopter. However, from the viewpoint of removal of the corneal reflection image, if the hole position of the perforated mirror 007 is disposed at a position substantially conjugate with the corneal reflection position, the line image reflected by the cornea can be removed.

  That is, in the L-OCT apparatus, the concave lens 004 is moved in the optical axis direction according to the diopter of the eye E, and the corneal reflection light of the linear measurement light in the eye E is imaged at a specific position by the convex lens 006 . Since this imaging position moves along the optical axis L 3, ghosting due to corneal reflected light guided to the line sensor 0 14 is reduced by moving the perforated mirror 007 so that the hole is disposed at the imaging position. it can. When such a focusing lens (concave lens 004) is simply moved in the direction of the optical axis (L2 in FIG. 1), the imaging position is also moved in accordance with this. Therefore, the lens unit and the perforated mirror 007 need to be interlocked or synchronously controlled correspondingly, but with such a configuration, ghosting due to corneal reflected light can be eliminated. That is, when viewed from the viewpoint of removal of ghosts by corneal reflected light, at least a concave lens 004 (optical member) that moves the optical axis of the measurement light to focus the measurement light on the eye, and a perforated mirror 007 You need to move in synchronization. At this time, the concave mirror 004 moves along the optical axis of the measurement optical system (irradiation optical system) (the part coincident with the optical axis of the return light), and the perforated mirror 007 moves along the optical axis of the sampling optical system. As a result, most of the imaged corneal reflected light is removed by the perforated mirror 007. Even in such a configuration, it is preferable to dispose the beam splitter 005 which branches the optical axis L3 from the optical axis L2. A member for reducing the corneal reflection light such as the perforated mirror 007 may be disposed on the optical axis L3.

  However, the focusing lens unit and the perforated mirror 007 also have a role of making the on the fundus oculi Ef and the top of the line sensor 014 a conjugate relationship with respect to the return light of the measurement light from the fundus oculi Ef. Therefore, the positional relationship between the convex lens 008 having a collimator function and the virtual plane f0 'can not be basically changed, and the convex lens 006 constituting the imaging optical system basically moves along the optical axis L2 or L3. There is basically no need to do this. Therefore, in order to remove the corneal reflection light at the imaging position, it is preferable to move only the perforated mirror 007 along the optical axis L3. When the focusing operation according to the diopter is performed on that, when the return light reaches the perforated mirror 007, the imaging magnification of the return light including the corneal reflection light is different. This causes the fluctuation of the light quantity of the return light removed by the perforated mirror 007 and the change of the light reception efficiency of the return light received by the line sensor 014.

  In view of such a situation, in the present embodiment, the corneal reflected light is collimated by the convex lens 003 disposed at the front stage of the focusing unit 100. Then, this is made to be incident on the focusing unit 100 (concave lens 004) which moves on the optical axis L2 in a parallel light state. Therefore, regardless of the position on the optical axis L2 of the focusing unit 100, the corneal reflection light always forms a line image in the hole of the perforated mirror 007.

  Further, the return light is converted into parallel light by the concave lens 004, and this is imaged by the convex lens 006 on the virtual plane f0 '. The return light emitted from the focusing unit 100 is collimated by the convex lens 008 disposed downstream of the perforated mirror 007. Further, the optical axis L2 and the optical axis L4 are arranged to be parallel to each other. With such a configuration, the line sensor 014 has a conjugate relationship with the virtual plane f0 ′, the virtual plane f0, and the fundus oculi Ef, and the focusing operation according to the diopter is performed. Even if there is, the relationship will not change. Therefore, by arranging the focusing unit 100 having such a configuration, it is possible to remove the corneal reflection light with a constant efficiency without performing complicated control such as interlocking between the lens unit and the perforated mirror 007 described above. Is possible.

  That is, by using the L-OCT apparatus having the above configuration, it is possible to reduce the incidence on the line sensor 014 of the corneal reflection light of the line image generated when the line-like measurement light is irradiated to the eye to be examined. . Therefore, it becomes possible to provide a clear tomogram without being affected by ghosts due to such corneal reflection light.

  As described above, the L-OCT apparatus, which is the ophthalmologic apparatus described in the present embodiment, shapes the measurement light into a line, irradiates the line-shaped measurement light onto the fundus oculi Ef, and scans the fundus oculi Ef. And an irradiation optical system including an optical member from the optical fiber end 010 to the objective lens 001. It also includes a sampling optical system (light receiving optical system) for focusing the return light from the fundus oculi Ef of the measurement light on the line sensor 014 (light receiving means) as light receiving means. In this sampling optical system, from the return light from the fundus oculi Ef, the measurement light is irradiated to the fundus oculi Ef and becomes a return light, and the corneal reflection light which is included in the return light in the process of reaching the sampling optical system is reduced The focused light is imaged on the line sensor 014. The L-OCT apparatus according to the present embodiment further includes a focusing unit 100 that moves in a direction along an optical axis L2, which is a part of the optical axis of return light overlapping the optical axis of the measurement light. The focusing unit 100 includes an objective lens 001 which is a part of the irradiation optical system and the light receiving optical system, a galvanometric mirror 002, a convex lens 003, a concave lens 004, and an intra-unit beam splitter 005. The concave lens 004 functions as a focusing member for focusing measurement light on the eye to be examined, which is the fundus of the eye to be examined in this embodiment. The focusing unit 100 includes an imaging optical system and a corneal reflection removing member (reduction member) as a configuration for removing the corneal reflected light which is the reflected light from the test eye cornea Ec of the line image of the measuring light. . The corneal reflection removing member is moved to the imaging position of the corneal reflection image in synchronization with the movement of the concave lens 004 on the optical axis of the measurement light. As a result, most of the corneal reflected light imaged by the imaging optical system is separated from the optical path, and the separated portion is guided out of the optical axis or blocked, from the eye to be examined E incident on the line sensor 014 Reduce the corneal reflection light included in the return light. The imaging optical system is composed of a convex lens 006, and forms an image of the corneal reflection light from the cornea Ec of the linear measurement light. The focusing unit is configured to be movable along the optical axis of the irradiation optical system by integrating the concave lens 004 that is a focusing member for focusing measurement light on the fundus, the optical path branching means, the imaging member optical system, and the reduction member. Ru. By this integration, the movement of the concave lens 004 and the corneal reflection removing member on the optical axis is integrally performed, and the optical axis of the measurement light of these configurations follows the movement of the concave lens 004 on the optical axis. It becomes possible to move. Further, in the present embodiment, the corneal reflection removing member is constituted by the hole portion of the perforated mirror 007, and the corneal reflection light imaged by the imaging optical system is removed or reduced from the return light. By arranging such a configuration in the L-OCT apparatus, it is possible to easily reduce the corneal reflection light as described above.

  Further, in the present embodiment, in order to remove the corneal reflection light only by driving the focusing unit 100, the L-OCT apparatus further uses a convex lens 003 for causing the corneal reflection light to be incident on the focusing unit 100 as an infinite distance. Prepare. Then, the imaging optical system that forms the return light on the line sensor 014 makes the return light incident on the focus unit 100 via the convex lens 003 parallel light, and then the perforated mirror 007 removes the corneal reflection light The image is formed at a position different from The L-OCT apparatus further includes a galvanometric mirror 002 as a scanning unit that scans measurement light on the fundus oculi Ef. Here, the convex lens 003 described above sets the turning center of the galvanometric mirror 002 as the front focal position, in order to make the corneal reflection light enter the focus unit 100 as infinity.

  Further, the focusing unit 100 is provided with a concave lens 004 and a convex lens 006 as an optical member for forming an image of the return light on the line sensor 014. The concave lens 004 constitutes a focusing member having a negative focal length for making the return light incident in the focusing unit 100 parallel light. Further, the convex lens 006 constitutes an imaging optical system having a positive focal distance for focusing the return light which has been converted into parallel light. Furthermore, the focusing unit 100 includes an intra-unit beam splitter 005 as the above-mentioned optical path branching means for branching the optical path of the irradiation optical system and the optical path of the light receiving optical system. The intra-unit beam splitter 005 is disposed between the concave lens 004 and the convex lens 006. By arranging the intra-unit beam splitter 005 in this manner, it becomes easy to bend the sample optical system, the focus unit 100 can be made more compact, and the structure of the optical unit can be made smaller.

  The focusing unit 100 also includes a perforated mirror 007 and a convex lens 008 in order to form a line image on the fundus oculi Ef on the line sensor 014. The perforated mirror 007 constitutes a reflecting means for reflecting the return light, of which the optical path is split along the optical axis L3 by the intra-unit beam splitter 005, in the direction of the optical axis L4 parallel to the optical axis L2. In addition, the convex lens 008 constitutes an emission member having a positive focal distance for causing the return light reflected by the perforated mirror 007 to be emitted from the focus unit 100 as infinite distance. By including these components in addition to the convex lens 003, even if the position of the focus unit 100 on the optical axis L2 is changed according to the diopter of the eye E, the conjugate relationship between the fundus oculi Ef and the line sensor 014 does not change.

  In this embodiment, as the corneal reflection removing member (reduction member), a perforated mirror 007 which is disposed at a position where the corneal reflected light is imaged and has a region capable of transmitting the corneal reflected light is used. In this embodiment, in order not to reflect the corneal reflection light in the direction of the optical axis L4, a hole through which the corneal reflection light passes is provided on the mirror. However, the form of the corneal reflection removing member is not limited to this as long as the corneal reflected light is not reflected in the direction of the optical axis L4. For example, even if the position corresponding to the hole portion is made of a transparent member capable of transmitting light. Good. In addition, the area through which the corneal reflection light can be transmitted preferably has a slit shape corresponding to the linear measurement light. With such a slit shape, it is possible to minimize the decrease in the amount of return light guided to the line sensor 014.

Second Embodiment
Next, referring to FIG. 3, a second embodiment of the present invention will be described. In the first embodiment described above, the corneal reflection light is imaged on the hole of the perforated mirror 007, and the corneal reflection light is removed by using this hole. On the other hand, in the present embodiment, the influence of the ghost of the corneal reflection light is suppressed by blocking the corneal reflection light. Hereinafter, the optical layout of the L-OCT apparatus according to the present embodiment will be shown by FIG. 3, and items related to the difference from the first embodiment will be described.

  With regard to the optical members shown in FIG. 3, the same reference numerals are used for those exhibiting the same effects as those of the optical members described in FIG. 1, and the description thereof is omitted here. Further, since the imaging method and the like are also the same as in the first embodiment, the description here is omitted.

  In the first embodiment and the second embodiment, the configuration in the focusing unit is different. In the focusing unit 100 according to the first embodiment, the perforated mirror 007 is disposed at a position on the optical axis L3 on which the corneal reflected light is imaged, and the corneal reflected light is transmitted by passing the corneal reflected light through the hole. It was prevented from being led in the direction of axis L4. On the other hand, in the focus unit 300 of this embodiment, the black point plate 030 and the mirror 031 are arranged in place of the perforated mirror 007.

  The black dot plate 030 is disposed at a position on the optical axis L3 on which the corneal reflected light is imaged, and has a black dot that does not absorb or reflect the corneal reflected light to transmit it. By arranging such a black point plate 030, light other than the portion blocked by the black point portion of the black point plate 030 in the corneal reflection light and return light is reflected by the mirror 031 in the direction of the optical axis L4. As in the case of the hole shape of the perforated mirror 007, the black points of the black point plate 030 conform to the shape of the image by the corneal reflection light, and it is efficient if it is rectangular. Moreover, if it is a form which absorbs or reflects and does not permeate | transmit corneal reflected light, it will not be restricted to a black slit shape, A color and a shape can be changed arbitrarily.

  In the present embodiment, in the focus unit 300, the concave lens 004, the intra-unit beam splitter 005, the convex lens 006, the black dot plate 030, the mirror 031, and the convex lens 008 are integrated by a holding member or the like (not shown). Then, the focusing unit 300 is moved by the focusing unit driving means 1001 along the optical axis directions of the optical axes L2 and L4 according to the diopter of the eye E. That is, also in this embodiment, when the alignment between the eye E and the L-OCT apparatus is completed, even if the focusing operation according to the diopter of the eye E is performed, the corneal reflection by the focus unit 300 Light can be reduced and the optical path length of the measurement light can be kept constant.

  In the two embodiments described above, a corneal reflection removing member (reduction member) such as a perforated mirror or a black dot plate is disposed at the imaging position of the corneal reflection light of the linear measurement light in the focusing unit. By arranging such a corneal reflection removing member, corneal reflected light can be reduced. Further, in the state where the alignment is completed, the corneal reflected light entering the focusing unit is at infinity, and the light flux from the fundus emitted from the focusing unit is at infinity. With such a configuration, the corneal reflection light can be reduced with the same efficiency regardless of the diopter of the eye E, and the optical path length of the measurement light can be made constant even if the focusing operation is performed. . That is, the corneal reflection removing member in the present embodiment can be configured from a member which is disposed at a position where the corneal reflected light is imaged and absorbs or shields the corneal light. Then, similarly to the hole portion of the perforated mirror 007 in the first embodiment, the region to be absorbed or shielded may be a slit shape corresponding to the linear measurement light.

  In addition, in the Example mentioned above, the L-OCT apparatus using the injection light from a wavelength sweep light source is mentioned as an example as an apparatus which scans the measurement light shape | molded by line shape by the to-be-tested eye. However, the light source is not limited to the wavelength swept light source, and a light source that emits broadband low-coherence light can also be applied. Furthermore, the above-described focusing unit can be applied to a line scanning laser ophthalmoscope (L-SLO) for obtaining a two-dimensional fundus image without performing interference signal analysis or using a reference optical system. Also in this case, the corneal reflection light can be reduced by the focus unit regardless of the diopter of the eye E. The specific configuration in this case is, for example, a configuration excluding the configuration related to the beam splitter 012, the reference optical system 102, the collimator lens 015, the optical fiber end 016, and the reference light from the configuration shown in Example 1 or 2. It becomes.

  That is, in the above embodiment, when the present invention is applied to an L-OCT apparatus as an ophthalmologic apparatus, an interference optical system and a tomogram generating means are provided. The interference optical system combines the return light and the reference light corresponding to the return light to generate interference light. Further, the tomogram generation unit generates a tomogram of the fundus oculi Ef using the interference signal obtained from the interference light. In the embodiment, the beam splitter 012 is used as an interference unit, and the sampling unit 022, the control unit 020, and the signal processing unit 024 are used as tomographic image generation units. When applied to a line scanning SLO (scanning laser ophthalmoscope), the return light from the eye fundus Ef to be examined is received by the line sensor 014, and the obtained luminance information is used to obtain a front image of the fundus Ef. Generate Specifically, the SLO apparatus in this case includes a front image generating unit having a configuration exemplified by the sampling unit 022, the control unit 020, and the signal processing unit 024 described above.

  Further, in the embodiment described above, for example, the entrance member, the focusing member, the imaging member, the exit member and the like are constituted by lenses. However, as long as they have similar optical functions, they can be replaced by various known optical members such as concave mirrors.

  Furthermore, in the embodiment described above, the present invention relates to an ophthalmologic apparatus. However, the present invention can be grasped not as the ophthalmologic apparatus but also as the focus units 100 and 300 used in the ophthalmologic apparatus. In this case, the focusing units 100 and 300 according to the present invention include the imaging optical system, the focusing member, and the reduction member described above. The imaging optical system includes, for example, a convex lens 006, and forms an image of corneal reflected light from the cornea Ec of the eye to be examined E irradiated with the linear measurement light. The focusing member is provided with, for example, a concave lens 004, and moves along the optical axis (optical axis L2) of the irradiation optical system that irradiates the measurement light in the form of line to the fundus Er of the eye E to measure the line Focus on Er. The reduction member is exemplified in the hole of the perforated mirror 007, is disposed at the position where the corneal reflection light is imaged, and the corneal reflection is imaged from the return light from the eye E to which the line-like measurement light is irradiated. Reduce the light. The focusing unit is configured such that the focusing member, the imaging optical system, and the reduction member are integrally movable along the optical axis of the irradiation optical system.

  In the focusing units 100 and 300, the imaging optical system forms an image of the corneal reflection light from the cornea Ec of the eye E to be examined which is formed into a line shape different from the return light, which is incident on the focusing unit. Let The reducing member reduces the imaged corneal reflected light from the light receiving optical system. Further, the imaging optical system causes the return light incident on the focusing unit to be parallel light and then forms an image at a position different from the position where the reduction member reduces the corneal reflected light. The function of these imaging optical systems is to use a concave lens 004 which is a focusing member with a negative focal length for making the return light incident in the focusing unit a parallel light, and a focal length for focusing the return light made parallel light. It is performed by the convex lens 006 which is a positive imaging member. Further, an intra-unit beam splitter 005, which is an optical path branching means for branching the irradiation optical system and the light receiving optical system, is disposed between the concave lens 004 and the convex lens 006.

  The focusing units 100 and 300 are reflecting means for reflecting the return light separated in the optical path by the intra-unit beam splitter 005 to the optical axis L4 parallel to the optical axis L2 of the return light before the optical path separation. Prepare. As a specific reflecting means, in the above-described embodiment, the perforated mirror 007 or the mirror 031 is used. The focusing units 100 and 300 further include a convex lens 008 as an emitting member having a positive focal distance for causing the return light reflected by the reflecting means to be emitted from the focusing unit as infinity. By having the above configuration, in an ophthalmologic apparatus for obtaining information of an eye to be examined by irradiating linear measurement light, the effect of ghost due to corneal reflected light can be obtained by a simple mechanism without changing the optical path length of the measurement optical path. It can be reduced.

  Although the present invention has been described above with reference to the examples, the present invention is not limited to the above-described examples. Inventions modified without departing from the spirit of the present invention and inventions equivalent to the present invention are also included in the present invention. The above-described embodiments can be combined as appropriate without departing from the spirit of the present invention.

Eye to be examined E
Fundus Ef
Line image forming optical system 101
Reference optical system 102
Galvanometric mirror 002
Convex lens 003
Concave lens 004
In-unit beam splitter 005
Perforated mirror 007
Convex lens 008
Beam splitter 012
Line sensor 014

Claims (15)

An irradiation optical system for irradiating the fundus of the subject's eye with a linear measurement light;
An imaging optical system for imaging corneal reflected light from a cornea of the subject's eye;
A reducing member disposed at a position where the corneal reflected light is imaged, and reducing the imaged corneal reflected light from the return light from the fundus irradiated with the linear measurement light;
A light receiving optical system that receives the return light from which the corneal reflection light has been reduced;
An ophthalmologic apparatus comprising: A focusing member which moves along the optical axis of the irradiation optical system to focus the linear measurement light on the fundus;
An optical path branching unit that branches an optical path of the irradiation optical system and an optical path of the light receiving optical system;
A focusing unit configured to be movable along an optical axis of the irradiation optical system by integrating the imaging optical system disposed in the light receiving optical system, the reduction member, and the focusing member;
The ophthalmologic apparatus according to claim 1, further comprising: It further comprises an incidence member that causes the corneal reflected light to enter the focusing unit as being at infinity.
The imaging optical system forms the return light at a position different from the position at which the corneal reflection light is formed after the return light incident on the focus unit via the incident member is converted into parallel light. The ophthalmologic apparatus according to claim 2,   The ophthalmologic apparatus according to claim 3, further comprising: a scanning unit that scans the measurement light, wherein a pivot center of the scanning unit is located at a front focal point of the incident member. The focusing member has a negative focal length so as to make the return light incident in the focusing unit parallel light.
The ophthalmologic apparatus according to claim 3, wherein the image forming optical system includes an image forming member having a positive focal length for focusing the return light converted into the parallel light.   The focusing unit is a reflecting unit that reflects the return light separated in the optical path by the optical path branching unit in a direction parallel to the optical axis of the focusing member, and the return light reflected by the reflecting unit is infinite. The ophthalmologic apparatus according to any one of claims 2 to 5, further comprising: an emission member having a positive focal distance to be emitted from the focusing unit.   The ophthalmologic apparatus according to claim 6, wherein the reduction member is the reflection means disposed at a position where the corneal reflection light is imaged and having a region capable of transmitting the corneal reflection light.   The ophthalmologic apparatus according to claim 7, wherein the transmittable area has a slit shape corresponding to the linear measurement light.   The said reduction member consists of a member arrange | positioned in the position where the said corneal reflected light is imaged, and having an area | region which absorbs or shields the said corneal reflected light in any one of the Claims 2 thru | or 6 characterized by the above-mentioned. The ophthalmologic apparatus as described.   The ophthalmologic apparatus according to claim 9, wherein the area to be absorbed or blocked is in the form of a slit corresponding to the linear measurement light. A focusing member which moves along the optical axis of the irradiation optical system to focus the linear measurement light on the fundus;
It further comprises an optical path branching means for branching an optical path of the irradiation optical system and an optical path of the light receiving optical system,
The ophthalmologic apparatus according to claim 1, wherein the reduction member is disposed in the light receiving optical system and moves along an optical axis of the light receiving optical system in synchronization with the movement of the focusing member.   The ophthalmologic apparatus according to any one of claims 2 to 11, wherein the optical path branching means is disposed between the focusing member and the imaging optical system.   An interference optical system that combines the return light and a reference light corresponding to the return light to generate interference light, and a tomogram that generates a tomogram of the fundus using an interference signal obtained from the interference light The ophthalmic apparatus according to any one of claims 1 to 12, further comprising: generation means.   The ophthalmologic apparatus according to any one of claims 1 to 12, further comprising: a front image generation unit configured to generate a front image of the fundus using the return light. A focusing member configured to move along the optical axis of the irradiation optical system that irradiates the measurement light in the form of a line to the fundus of the subject's eye to focus the measurement light in the form of a line on the fundus;
An imaging optical system for imaging corneal reflected light from a cornea of the subject's eye;
A reducing member disposed at a position where the corneal reflected light is imaged, and reducing the imaged corneal reflected light from the return light from the fundus irradiated with the linear measurement light;
An optical path branching unit that branches an optical path of the irradiation optical system and an optical path of a light receiving optical system that receives the return light from which the corneal reflection light is reduced;
A focusing unit configured to be movable along an optical axis of the irradiation optical system by integrating the image forming optical system, the reduction member, and the focusing member, which are disposed in the light receiving optical system.

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