JP7431000B2 - ophthalmology equipment - Google Patents

Description

TECHNICAL FIELD This invention relates to an ophthalmological device.

In recent years, ophthalmological examinations using ophthalmological equipment are performed during screening. Such an ophthalmological device is also expected to be applied to self-examination, and further miniaturization and weight reduction are desired.

For example, Patent Document 1 and Patent Document 2 disclose an ophthalmological apparatus configured to pattern-illuminate a subject's eye using slit light and detect the returned light with a CMOS (Complementary Metal Oxide Semiconductor) image sensor. ing. This ophthalmological apparatus can acquire an image of the eye to be examined with a simple configuration by adjusting the illumination pattern and the timing of light reception by the CMOS image sensor.

US Patent No. 7831106 US Patent No. 8237835

In the conventional method, light modulation is performed in units of light-emitting pixels on the illumination side (projection side), and returned light is received in units of light-receiving pixels (light-receiving elements) on the light-receiving side. As a result, if there is not a one-to-one correspondence between the light-emitting pixels arranged on the illumination side and the light-receiving pixels arranged on the light-receiving side, uneven light reception (illumination-light reception unevenness) will occur, and the acquired image will be affected by e.g. Moiré stripes appear.

In reality, it is considered difficult to provide a one-to-one correspondence between light-emitting pixels and light-receiving pixels, not only from the viewpoint of cost or technology, but also because the range of parts selection is limited.

In this case, it is conceivable to reduce the influence of moiré fringes appearing in the image by, for example, performing image processing (smoothing, noise removal, brightness adjustment, etc.) on the acquired image. However, by performing image processing on an image, there is a possibility that the image deteriorates, such as a reduction in the definition and S/N ratio of the image, or the generation of artifacts.

Furthermore, for example, it is conceivable to refine at least one of the structure of the light-emitting pixel on the illumination side and the structure of the light-receiving pixel on the light-receiving side. However, this increases the cost of the device and increases the processing load of image processing.

The present invention was made to solve such problems, and its purpose is to provide a new technique for reducing image quality deterioration with a simple configuration.

A first aspect of some embodiments includes a projection unit that projects pattern light onto an eye to be examined, a projection unit that receives return light of the pattern light from the eye to be examined, and an aperture shape based on a result of receiving the return light. an acquisition unit that acquires a corresponding image of the subject's eye, and the projection unit generates pattern light in a projection shape extending at least in a direction substantially parallel to a first direction corresponding to an opening direction of the opening shape. The ophthalmologic apparatus includes a patterned light generating section and a diffusing section that diffuses the patterned light.

In a second aspect of some embodiments, in the first aspect, the diffusion section diffuses the patterned light in the first direction.

In a third aspect of some embodiments, in the second aspect, the diffusion section has a diffusion range for the patterned light in the first direction that is wider than a diffusion range for the patterned light in a second direction intersecting the first direction. The patterned light is diffused so that

In a fourth aspect of some embodiments, in any of the first to third aspects, the diffusing section is configured to reduce light reception unevenness of the patterned light, where Q is a pixel size ratio on the light receiving surface of the returned light. The light amount distribution of the patterned light is smoothed so that the reduction ratio is 0.285×Q or less.

In a fifth aspect of some embodiments, in any of the first to third aspects, the diffusing section is configured to reduce light reception unevenness of the patterned light, where Q is a pixel size ratio on the light receiving surface of the returned light. The light amount distribution of the patterned light is smoothed so that the reduction ratio is 0.76×Q or less.

In a sixth aspect of some embodiments, in any of the first to fifth aspects, the diffusion section includes a diffusion filter disposed in the optical path of the patterned light.

In a seventh aspect of some embodiments, in any of the first to sixth aspects, the diffusing section includes a birefringent plate disposed in the optical path of the patterned light.

In an eighth aspect of some embodiments, in any of the first to seventh aspects, the diffusing section includes a diffractive optical element disposed in the optical path of the patterned light.

In a ninth aspect of some embodiments, in any of the first to eighth aspects, the diffusion section includes an optical lens disposed in the optical path of the patterned light, and uses the aberration of the optical lens. Diffusing the pattern light.

In a tenth aspect of some embodiments, in the ninth aspect, the optical axis of the optical lens is arranged to be inclined with respect to the optical path of the pattern light.

In an eleventh aspect of some embodiments, in any of the first to tenth aspects, the diffusion section includes a plane parallel plate arranged to be inclined with respect to the optical path of the patterned light.

In a twelfth aspect of some embodiments, in any of the first to eleventh aspects, the patterned light generating section includes a light source and a light source that generates the patterned light by spatially modulating the light from the light source. and a spatial light modulator for generating the spatial light modulator.

In a thirteenth aspect of some embodiments, in any one of the first to twelfth aspects, the acquisition unit includes an image sensor that receives the return light, and receives a result of reception of the return light by the image sensor. An image of the eye to be examined is acquired by reading out using a rolling shutter method.

Note that it is possible to arbitrarily combine the configurations according to the plurality of aspects described above.

According to the present invention, a new technique for reducing deterioration in image quality can be provided with a simple configuration.

FIG. 1 is a schematic diagram showing a configuration example of an ophthalmologic apparatus according to an embodiment. FIG. 1 is a schematic diagram showing a configuration example of an ophthalmologic apparatus according to an embodiment. FIG. 3 is an explanatory diagram of the operation of an ophthalmologic apparatus according to a comparative example of the embodiment. FIG. 2 is an explanatory diagram of the operation of the ophthalmologic apparatus according to the embodiment. FIG. 2 is an explanatory diagram of the operation of the ophthalmologic apparatus according to the embodiment. FIG. 2 is an explanatory diagram of the operation of the ophthalmologic apparatus according to the embodiment. FIG. 2 is an explanatory diagram of the operation of the ophthalmologic apparatus according to the embodiment. FIG. 1 is a schematic diagram showing a configuration example of an ophthalmologic apparatus according to an embodiment. It is a flow diagram of an example of operation of an ophthalmological device concerning an embodiment. It is a schematic diagram showing an example of composition of an ophthalmologic device concerning a modification of an embodiment.

An example of an embodiment of an ophthalmologic apparatus according to the present invention will be described in detail with reference to the drawings. Note that the contents of the documents described in this specification can be appropriately cited as the contents of the following embodiments.

The ophthalmological apparatus according to the embodiment includes a projection system that projects pattern light onto an eye to be examined, and a light receiving system that receives return light of the pattern light from the eye to be examined, and the ophthalmological apparatus includes It is possible to obtain an image of the fundus of the eye to be examined based on the following. Patterned light is generated, for example, by spatially modulating light. In some embodiments, the ophthalmological device uses a configuration similar to that described above to obtain images of the anterior segment of the subject's eye.

For example, the projection system projects onto the subject's eye a slit-shaped (line-shaped) pattern of light extending in a direction substantially parallel to the aperture direction (direction corresponding to the aperture direction) of the aperture shape on the light receiving side. The ophthalmological apparatus acquires a received light image corresponding to the shape of the aperture from the result of receiving the returned light obtained by the light receiving system. At this time, the projection system diffuses the patterned light generated by spatial modulation in a direction substantially parallel to the aperture direction and projects it onto the eye to be examined. In the light receiving system, the result of receiving the returned light is read out using, for example, a rolling shutter method. As a result, even if the arrangement of light-emitting pixels in the projection system and the arrangement of light-receiving pixels in the light-receiving system do not correspond one-to-one, the effect of uneven light reception that appears in the acquired image is reduced and image quality deterioration is prevented. can do.

In this specification, "spatially modulating light" refers to, for example, changing the wavelength, intensity, polarization direction, phase, etc. of light in one-dimensional space, two-dimensional space, or three-dimensional space. For example, it is realized using a light source and a spatial light modulator, or it is realized using a self-emitting device. Furthermore, unless otherwise specified, the "direction" of the pattern light, the "direction" of the aperture shape or received light image, and the aperture direction do not mean the direction at each position in the absolute coordinate system, but rather It means a direction on a surface (for example, a light receiving surface in a light receiving system).

[Optical system configuration]
FIGS. 1 and 2 show block diagrams of exemplary configurations of ophthalmological apparatuses according to embodiments. 1 and 2 mainly represent block diagrams of exemplary configurations of the optical system of the ophthalmologic apparatus 1 according to the embodiment. In FIG. 1 and FIG. 2, the same parts are given the same reference numerals, and the explanation will be omitted as appropriate.

The ophthalmological apparatus 1 projects a pattern of light corresponding to the aperture shape on the light-receiving side onto the eye E to be examined, and receives the returned light to obtain an image of the image (fundus) of the eye E to be examined corresponding to the aperture shape. is possible.

The ophthalmological apparatus 1 includes a projection system 10, a light receiving system 20, an image processing section 30, and an image output section 40.

The projection system 10 projects pattern light having a projection shape (for example, slit shape, line shape) extending in a direction substantially parallel to the aperture direction (direction corresponding to the aperture direction) corresponding to the aperture shape of the light receiving system 20 in the aperture direction. The images are sequentially projected onto the subject's eye E in a direction perpendicular to . The light receiving system 20 sequentially receives the returned light of the pattern light projected onto the eye E by the projection system 10. The image processing unit 30 sequentially acquires received light images corresponding to the aperture shape while shifting the aperture shape in a direction perpendicular to the aperture direction (or an aperture cross direction) from the result of the return light received by the light receiving system 20. , an image of the fundus of the eye E to be examined is acquired.

(Projection system 10)
Projection system 10 includes a pattern light generating section 11, a smoothing section 12, and an optical system 13.

(Pattern light generating section 11)
The pattern light generating section 11 generates pattern light having a predetermined projection shape by spatially modulating light. The pattern light generating section 11 can generate pattern light having a desired projection shape by spatially controlling light modulation. That is, the pattern light generating section 11 includes a plurality of light emitting pixels arranged two-dimensionally, and realizes a function as a pixelated pattern light generator. For example, the pattern light generation section 11 generates pattern light whose projection shape can be arbitrarily changed under control from a control section described below. Thereby, the projection position and projection range of the pattern light can be changed in the imaging region of the eye E to be examined.

In this embodiment, the pattern light generating section 11 is controlled by a control section to be described later, and generates pattern light in a projected shape extending at least in a direction substantially parallel to the aperture direction (that is, a direction corresponding to the aperture direction). is possible.

As shown in FIG. 2, the pattern light generator 11 includes a light source 11A, an optical system 11B, and a spatial light modulator 11C. A projector is an example of the pattern light generating section 11 having such a configuration. That is, the pattern light generating section 11 includes a light source 11A, an optical system 11B, and a spatial light modulator 11C that correspond to the type of projector. The light source 11A can be placed at a position that is optically substantially conjugate with the imaging site of the eye E (for example, the fundus of the eye, the anterior segment of the eye).

In some embodiments, the light source 11A is a light source that can switch and output light in the infrared region or near-infrared region, and light in the visible region. For example, the light source 11A outputs light in an infrared region or near-infrared region during an alignment operation or focusing control, and outputs light in a visible region during a photographing operation. In this case, the pattern light generator 11 can output an optotype for alignment operation or an indicator during focus control as pattern light.

In some embodiments, the pattern light generator 11 has the function of a DLP (Digital Light Processing (registered trademark)) projector using a digital micromirror device. In this case, in the first configuration example, a single digital micromirror device is used for light in the infrared region or near-infrared region. In the second configuration example, a digital micromirror device common to RGB color components is used for light from a white light source. In the third configuration example, a digital micromirror device is used for each RGB color component for light from a white light source.

In the first configuration example, the light source 11A includes, for example, an LED (Light Emitting Diode) light source that emits light in an infrared region or a near-infrared region. Further, the optical system 11B includes a relay optical system and an optical lens. Moreover, the spatial light modulator 11C includes a digital micromirror device in which a plurality of mirror elements are two-dimensionally arranged. Each of the plurality of mirror elements is independently controllable. Note that the spatial light modulator 11C can include a projection lens for projecting light spatially modulated by the digital micromirror device.

In the second configuration example, the light source 11A includes a white light source or a light source capable of outputting light of each color component of RGB. Further, the optical system 11B includes a color wheel, a relay optical system, and an optical lens for time-divisionally outputting light of each color component of RGB from the light from the light source 11A. Moreover, the spatial light modulator 11C includes a digital micromirror device in which a plurality of mirror elements are two-dimensionally arranged. Note that the spatial light modulator 11C can include a projection lens for projecting light spatially modulated by the digital micromirror device.

In the third configuration example, the light source 11A includes a white light source or a light source capable of outputting light of each RGB color component. Further, the optical system 11B includes a relay optical system and an optical lens. Moreover, the spatial light modulator 11C includes a plurality of digital micromirror devices provided for each RGB color component. Note that the spatial light modulator 11C can include a projection lens for projecting light spatially modulated by the digital micromirror device.

In some embodiments, the pattern light generator 11 has the function of a reflective liquid crystal projector using LCoS (Liquid Crystal on Silicon). In this case, the light source 11A includes a white light source. Further, the optical system 11B includes one or more reflective mirrors, one or more dichroic mirrors, and one or more polarizing beam splitters. In addition, the spatial light modulator 11C includes a reflective liquid crystal panel for each RGB color component, a cross dichroic prism for combining spatially modulated light for each color component, and a projector for projecting the combined light. and a projection lens for.

In some embodiments, the pattern light generator 11 has the function of a transmissive liquid crystal projector. In this case, the light source 11A includes a white light source. Further, the optical system 11B includes one or more reflective mirrors and one or more dichroic mirrors. In addition, the spatial light modulator 11C includes a transmissive liquid crystal panel for each RGB color component, a cross dichroic prism for combining spatially modulated light for each color component, and a cross dichroic prism for projecting the combined light. and a projection lens for.

In some embodiments, the pattern light generator 11 has the function of a known projector using MEMS (Micro Electro Mechanical Systems).

Note that since the configuration of the projector as described above is well known, detailed explanation will be omitted. The pattern light generator 11 may be capable of outputting pattern light (illumination light) corresponding to an illumination pattern whose projection shape (projection position and projection range) can be arbitrarily changed.

The pattern light generating section 11 is controlled by a control section, which will be described later, and generates pattern light having an arbitrary projection shape. The projection shape can be set by the user using, for example, an operation unit described below. When the user uses the operation unit to specify a shape pattern, external shape, size, etc., the control unit specifies an illumination pattern based on the specified shape pattern, etc., and adjusts the spatial light modulator based on the specified illumination pattern. 11C.

(Smoothing unit 12)
The smoothing unit 12 smoothes the light amount distribution of the pattern light in the slit direction by diffusing the pattern light in the slit direction (that is, the aperture direction of the light receiving system 20 or a direction corresponding to the aperture direction). That is, the smoothing section 12 smoothes the pattern light in the slit direction. Specifically, the smoothing unit 12 smoothes the pattern light so that the diffusion characteristics in the slit direction are different from the diffusion characteristics in a direction perpendicular to (crossing) the slit direction. Here, the transmission angle θ1 of the transmitted light relative to the predetermined incident angle θ0 for the slit direction component of the pattern light is larger than the transmission angle θ2 of the transmitted light relative to the predetermined incident angle θ0 for the directional component of the pattern light perpendicular to the slit direction.

In some embodiments, the smoothing unit 12 changes the diffusion range (diffusion characteristics, degree of diffusion) of the pattern light under control from a control unit described below. In some embodiments, the smoothing unit 12 changes the diffusion range of the pattern light depending on the image quality of the image of the eye E to be examined.

3 and 4 are explanatory diagrams of uneven light reception according to the embodiment. FIG. 3 schematically represents uneven light reception in a comparative example of the embodiment. FIG. 4 schematically represents uneven light reception according to the embodiment.

FIG. 3 schematically represents a case where the light-receiving pixels PDT arranged in the image sensor of the light-receiving system do not correspond one-to-one to the light-emitting pixels PIL arranged in the pattern light generating section of the projection system. FIG. 4 shows that in the embodiment, when the light receiving pixels PDT arranged in the image sensor 22 do not have a one-to-one correspondence to the light emitting pixels PIL arranged in the pattern light generating part 11, the smoothing part 12 This schematically represents the case where the pattern light is diffused.

As shown in FIG. 3, when the arrangement of the light-emitting pixels PIL does not correspond to the arrangement of the light-receiving pixels PDT, the light-receiving level (light amount level) Pa of the return light of the pattern light received on the light-receiving side (light-receiving system 20) is Unevenness (dispersion) occurs for each element (light-receiving pixel). In contrast, in FIG. 4, the smoothing section 12 diffuses the pattern light in the slit direction as described above. As a result, even if the arrangement of the light emitting pixels PIL does not correspond to the arrangement of the light receiving pixels PDT, the light reception level (light intensity level) of the return light of the pattern light received in the light receiving system 20 due to the diffusion of the pattern light described above ) Pb is smoothed. Therefore, unevenness in the light reception level for each light receiving element (light receiving pixel) is reduced.

In this way, the influence of unevenness appearing in the image of the eye E can be reduced by the effect of the diffusion (smoothing) of the pattern light by the smoothing unit 12.

In some embodiments, the smoothing unit 12 smoothes the pattern light so that the diffusion range of the pattern light in the slit direction is wider than the diffusion range of the pattern light in a direction perpendicular to (crossing) the slit direction. That is, the smoothing unit 12 smoothes the pattern light so that the light receiving elements in the direction orthogonal to the aperture direction (slit direction) do not receive the diffused pattern light. This makes it possible to prevent image quality from deteriorating due to blurring due to smoothing in a direction perpendicular to the aperture direction.

5 and 6 are explanatory diagrams of the operation of the smoothing section 12 according to the embodiment. For convenience of explanation, FIGS. 5 and 6 schematically represent the one-dimensional structure of the light-emitting pixels of the projection system 10 and the one-dimensional structure of the light-receiving pixels in the image sensor 22 of the light-receiving system 20.

FIG. 5 schematically represents the arrangement of the light emitting pixels and the light receiving pixels when the light generated from the light emitting pixels on the projection side (projection system 10) is directly received by the light receiving pixels on the light receiving side (light receiving system 20). It is. FIG. 6 schematically shows the arrangement of the light-emitting pixels and the light-receiving pixels when a part of the light generated from the light-emitting pixels on the projection side is received by the light-receiving pixels on the light-receiving side.

5 and 6, on the projection side, the pixel period (light emitting pixel period) of the light emitting pixel PIL in the slit direction is Λi, the size of the light emitting pixel PIL in the slit direction is Pi, and the interpixel gap of the light emitting pixel PIL is Gi. shall be. Λi is expressed as in the following equation (1).

Λi=Pi+Gi...(1)

Similarly, on the light receiving side, when considering the optical magnification in the projection system 10 and the optical magnification in the light receiving system 20, the pixel period in the aperture direction of the light receiving pixel PDT (light receiving pixel period) is Λd, and the pixel period in the aperture direction of the light receiving pixel PDT is Λd. The size is assumed to be Pd, and the interpixel gap of the light receiving pixel PDT is assumed to be Gd. Λd is expressed as in the following equation (2).

Λd=Pd+Gd...(2)

Here, a first case where Pi<Pd, a second case where Pi=Pd, and a third case where Pi>Pd are considered.

The first case means that the light emitting pixel density on the projection side is lower than the light receiving pixel density on the light receiving side. In other words, the resolution on the light-receiving side is higher than that on the projection side, which only increases costs and is considered to be a case that is difficult to practically adopt.

In the second case, as shown in Figure 5, the entire light-receiving pixel is irradiated with light from the light-emitting pixel, so the luminous efficiency (illumination efficiency) η is expressed as the following equation (3). be done.

η=1...(3)

On the other hand, in the third case, as shown in FIG. 6, in the light-receiving pixel, the part corresponding to the inter-pixel gap of the light-emitting pixel is not irradiated with light from the light-emitting pixel, so the luminous efficiency η is as follows. It is expressed as in equation (4).

η=(Pd-Gi)/Pd=(1-Gi/Pd)...(4)

That is, due to the decrease in the light reception level caused by Gi/Pd, uneven light reception appears in the acquired image.

In this way, both the light-emitting pixel period Λi on the projection side and the light-receiving pixel period Λd on the light-receiving side substantially affect the resolution of the image, so it is possible that the light-emitting pixel period Λi and the light-receiving pixel period Λd are approximately the same. considered practical. Specifically, the light-receiving pixel period Λd on the light-receiving side is about 0.3 to 3.0 times the light-emitting pixel period Λi on the projection side. In some embodiments, the receiving pixel period Λd on the receiving side is 0 with respect to the emitting pixel period Λi on the projecting side, considering that high-definition lighting elements are expensive and controlling the lighting elements is complex. .3 to 1.0 times.

Here, if the aperture ratio in the one-dimensional direction (slit direction) on the projection side is Ri, and the aperture ratio in the one-dimensional direction (aperture direction) on the light-receiving side is Rd, then Ri can be expressed as in the following equation (5). and Rd is expressed as in the following equation (6).

Ri=Gi/Λi...(5)
Rd=Gd/Λd...(6)

Furthermore, when the pixel size ratio on the light receiving surface of the image sensor 22 is Q, Q is expressed as in the following equation (7).

Q=Λd/Λi...(7)

As mentioned above, if the light-receiving pixel period Λd on the light-receiving side is 0.3 to 1.0 times the light-emitting pixel period Λi on the projection side, the pixel size ratio Q is 1 or less, and Pi>Pd Or when Pi=Pd, the maximum luminous efficiency is η=1.

On the other hand, the minimum luminous efficiency η is expressed as the following equation (8) using equations (2), (5), and (6).

η=1-Gi/Pd=1-(Λi×Ri)/(Λd×(1-Rd)) ...(8)

As described above, light reception unevenness expressed by equation (8) occurs depending on the arrangement of light-emitting pixels on the projection side and the arrangement of light-receiving pixels on the light-receiving side.

The allowable range of unevenness depicted in the image differs depending on the region to be imaged. For example, in a fundus image in which the shape of the fundus and blood vessels are depicted, it is necessary to suppress uneven light reception to a predetermined reduction amount RD or less. If the general allowable range of gradation collapse in the fundus image and the cost of the projection system 10 and the light receiving system 20 are rationally considered, the reduction amount RD is in the range of 0.03 to 0.08.

The reduction amount RD=0.03 is determined, for example, from the viewpoint of cost. For example, when RD<0.02, the cost increases even though the image quality is within an acceptable range.

The reduction amount RD=0.08 is determined, for example, from the viewpoint of the image characteristics of the fundus image. For example, when RD>0.08, the image quality is unacceptable as a fundus image.

Here, assuming that the second term of equation (8) is AT, in order to suppress AT to the reduction amount RD or less, the light receiving unevenness reduction ratio Z expressed as the following equation (9) or less should be set. It is necessary to diffuse (smooth) the pattern light.

Z=RD/AT=RD×(Λd×(1-Rd))/(Λi×Ri)
=RD×Q×(1-Rd)/Ri...(9)

The above description has been made using an example in which each of the light-emitting pixel and the light-receiving pixel has a one-dimensional structure for the sake of simplification, but the actual pixel structure is a two-dimensional structure.

FIG. 7 schematically represents the two-dimensional structure of the light-emitting pixel PIL of the projection system 10 and the two-dimensional structure of the light-receiving pixel PDT in the image sensor 22 of the light-receiving system 20. For convenience of explanation, FIG. 7 schematically represents a two-dimensional arrangement of light-emitting pixels PIL and a two-dimensional arrangement of light-receiving pixels PDT on the light-receiving surface of the image sensor 22.

In the arrangement of the light-emitting pixel PIL and the light-receiving pixel PDT as shown in FIG. 7, when the second term of equation (8) is AT, it is necessary to suppress 2×AT to the reduction amount RD or less. For this purpose, the smoothing unit 12 needs to diffuse (smooth) the pattern light so that it becomes equal to or less than the light reception unevenness reduction ratio Z expressed as the following equation (10).

Z=RD/(2×AT)=RD×(Λd×(1-Rd))/(Λi×Ri)
=1/2×RD×Q×(1-Rd)/Ri...(10)

For example, when Ri=Rd=0.05 and Q=0.3, when the light reception unevenness reduction amount RD=0.03, the light reception unevenness reduction ratio Z is as shown in the following equation (11).

Z=RD/(2×AT)=0.5×0.03×0.3×95/5=0.0855
...(11)

In this case, as shown in equation (11), it is necessary to suppress the unevenness of light reception to about 1/12 or less.

For example, when Ri=Rd=0.05 and Q=1.0, when the light reception unevenness reduction amount RD=0.06, the light reception unevenness reduction ratio Z is as shown in the following equation (12).

Z=RD/(2×AT)=0.5×0.06×1.0×95/5=0.57
...(12)

In this case, as shown in equation (12), it is necessary to suppress the unevenness of light reception to about 1/2 or less.

As described above, the smoothing unit 12 adjusts the pattern light depending on the light emitting pixel structure on the projection side and the light receiving pixel structure on the light receiving side when considering the optical magnification of the projection system 10 and the optical magnification of the light receiving system 20. Smooth.

For example, when Ri=Rd=0.05 and the amount of light reception unevenness reduction RD=0.03 to 0.08, the smoothing unit 12 uses the pixel size ratio Q on the light reception surface of the image sensor 22 as follows. The pattern light is smoothed in the slit direction so that it becomes equal to or less than the light reception unevenness reduction ratio Z.

In some embodiments, when RD=0.03, the light reception unevenness reduction ratio Z is expressed as in equation (13).

Z=0.5×0.03×Q×95/5=0.285×Q...(13)

In this case, the smoothing unit 12 smoothes the pattern light in the slit direction so that the light reception unevenness reduction ratio becomes 0.285×Q or less. As a result, regardless of the arrangement of the light-emitting pixels on the projection side and the arrangement of the light-receiving pixels on the light-receiving side, the image quality of the fundus image of the eye E to be examined can be prevented from deteriorating due to uneven light reception, without increasing the cost as described above. It will be possible to prevent this.

In some embodiments, when RD=0.08, the light reception unevenness reduction ratio Z is expressed as in equation (14).

Z=0.5×0.08×Q×95/5=0.76×Q...(14)

In this case, the smoothing unit 12 smoothes the pattern light in the slit direction so that the light reception unevenness reduction ratio is 0.76×Q or less. As a result, regardless of the arrangement of the light-emitting pixels on the projection side and the arrangement of the light-receiving pixels on the light-receiving side, it is possible to obtain the image of the eye E at low cost and without being affected by uneven light reception, within the allowable range of image quality as a fundus image. It becomes possible to prevent deterioration of the image quality of the fundus image.

In some embodiments, the smoothing unit 12 includes a diffusion filter (optical low-pass filter) placed in the optical path of the patterned light. The diffusion filter diffuses the pattern light so that the diffusion range in the slit direction is wider than the diffusion range in the direction perpendicular to the slit direction. Thereby, the light amount distribution of the pattern light is smoothed in the slit direction. An example of a diffusion filter is a lens diffusion plate. In some embodiments, the smoothing unit 12 includes a plurality of diffusion filters having different diffusion ranges, and selectively arranges the plurality of diffusion filters in the optical path of the pattern light under control from a control unit described below. to change the diffusion range of the pattern light.

In some embodiments, the smoothing unit 12 includes a birefringent plate disposed in the optical path of the patterned light and having a birefringence index. The birefringent plate refracts (diffuses) the patterned light so that the refraction range (diffusion range) in the slit direction is wider than the refraction range in the direction perpendicular to the slit direction. Thereby, the light amount distribution of the pattern light is smoothed in the slit direction. In some embodiments, the smoothing unit 12 includes a plurality of birefringent plates having different refraction ranges, and selectively arranges the plurality of birefringence plates in the optical path of the patterned light under control from a control unit described below. By doing so, the refraction range of the pattern light is changed.

In some embodiments, the smoothing unit 12 includes a diffractive optical element placed in the optical path of the patterned light. The diffractive optical element diffracts (diffuses) the patterned light so that the diffraction range (diffusion range) in the slit direction is wider than the diffraction range in the direction perpendicular to the slit direction. Examples of the diffractive optical element include a diffractive optical element using Fresnel diffraction and a diffractive optical element using the Talbot effect. Thereby, the light amount distribution of the pattern light is smoothed in the slit direction. In some embodiments, the smoothing unit 12 includes a plurality of diffractive optical elements having different diffraction ranges, and selectively arranges the plurality of diffractive optical elements in the optical path of the patterned light under control from a control unit described below. By doing so, the diffraction range of the pattern light is changed.

In some embodiments, the smoothing unit 12 includes one or more optical lenses disposed in the optical path of the patterned light, and uses at least one aberration of the one or more optical lenses to diffuse the patterned light in the slit direction. . Thereby, the light amount distribution of the pattern light is smoothed in the slit direction. In some embodiments, the optical axis of at least one of the one or more optical lenses is arranged to be oblique to the optical path of the patterned light. In some embodiments, the smoothing unit 12 includes a mechanism for changing the inclination angle of at least one optical axis of the one or more optical lenses with respect to the optical axis of the projection system 10, and the smoothing unit 12 includes a mechanism for changing the inclination angle of at least one optical axis of the one or more optical lenses, and controls as described below. The mechanism changes the inclination angle of at least one optical axis of the one or more optical lenses with respect to the optical axis of the projection system 10 under control from the projection system 10 .

In some embodiments, the smoothing unit 12 includes one or more optical lenses disposed in the optical path of the patterned light, and at least one of the one or more optical lenses has an optical axis that is aligned with the optical axis of the projection system 10. are placed a predetermined distance apart from each other. Thereby, it becomes possible to diffuse the pattern light in the slit direction, and the light amount distribution of the pattern light is smoothed in the slit direction. In some embodiments, the smoothing unit 12 includes a mechanism for changing the distance of at least one optical axis of the one or more optical lenses with respect to the optical axis of the projection system 10 in a direction perpendicular to the optical axis. The mechanism changes the distance of at least one optical axis of the one or more optical lenses with respect to the optical axis of the projection system 10 under control from a control unit to be described later.

In some embodiments, the smoothing unit 12 includes a plane-parallel plate arranged so as to be inclined with respect to the optical path of the patterned light. The parallel plane plate changes the optical axis (optical path) of the incident pattern light toward the slit direction. Thereby, the light amount distribution of the pattern light is smoothed in the slit direction. In some embodiments, the smoothing unit 12 includes a mechanism for changing the inclination angle of the plane parallel plate with respect to the optical axis of the projection system 10, and is controlled as described below. The inclination angle of the parallel plane plate is changed with respect to the optical axis of 10.

In some embodiments, the smoothing unit 12 includes a wedge prism arranged so that the pattern light is incident on an optical surface that is inclined with respect to the exit surface. The wedge prism refracts (diffuses) the pattern light that is incident on the optical surface and emits it from the exit surface. Thereby, the light amount distribution of the pattern light is smoothed in the slit direction. In some embodiments, the smoothing unit 12 includes a mechanism for changing the inclination angle of at least one of the optical surface and the exit surface of the wedge prism with respect to the optical axis of the projection system 10, and the smoothing unit 12 includes a mechanism for changing the inclination angle of at least one of the optical surface and the exit surface of the wedge prism, In response to this, the mechanism changes the inclination angle of at least one of the optical surface and the output surface of the wedge prism with respect to the optical axis of the projection system 10.

In some embodiments, the smoothing section 12 has a configuration in which two or more of the above members are arbitrarily combined. Specifically, the smoothing unit 12 includes at least two of a diffusion filter, a birefringent plate, a diffractive optical element, one or more optical lenses, a plane parallel plate, and a wedge prism. In some embodiments, the smoothing unit 12 further includes a mechanism that changes the inclination angle of at least one of the one or more optical lenses with respect to the optical axis of the projection system 10, or a mechanism that changes the inclination angle of at least one of the one or more optical lenses with respect to the optical axis of the projection system 10. It includes a mechanism for changing the distance of at least one optical axis of one or more optical lenses.

(Optical system 13)
The optical system 13 includes a relay optical system for relaying the pattern light smoothed by the smoothing section 12. In some embodiments, optical system 13 further includes a collimating lens and an optical scanner. In this case, the optical scanner can deflect the pattern light under control from a control section, which will be described later.

The pattern light that has passed through the optical system 13 is reflected by the optical multiplexer/demultiplexer 50 and guided to the optical system 51.

(Optical multiplexer/demultiplexer 50)
The optical multiplexer/demultiplexer 50 guides the light from the projection system 10 to the optical system 51 and guides the light from the optical system 51 to the light receiving system 20 . Such a function of the optical multiplexer/demultiplexer 50 can be realized by a beam splitter or a dichroic mirror.

(Optical system 51)
The optical system 51 is arranged between the optical multiplexer/demultiplexer 50 and the eye E to be examined. Some of the optical systems 51 include at least one of an objective lens, a focusing mechanism, and a correction optical system that corrects the astigmatic state of the eye E to be examined. In some embodiments, optical system 51 includes an anterior lens for moving the focal position of the patterned light closer to the anterior segment of the eye. In this case, the front lens is provided so that it can be inserted into and removed from the optical path of the pattern light.

Examples of focusing mechanisms include a focusing lens that can be moved along the optical axis direction (the direction of the optical path of the patterned light), a liquid lens that can change the refractive index, a liquid crystal lens that can change the refractive index, and a liquid crystal lens that can change the refractive index. There is an objective lens that can be moved along.

The focusing lens or objective lens can be moved in the optical axis direction automatically or manually. For example, the ophthalmological apparatus 1 includes a moving mechanism that moves at least one of the focusing lens and the objective lens in the optical axis direction, and the control unit controls the moving mechanism to move at least one of the focusing lens and the objective lens along the optical axis. Focusing can be controlled by moving in the direction. Further, for example, the user can manually adjust the focusing state by moving at least one of the focusing lens and the objective lens in the optical axis direction by operating the moving mechanism.

Further, the control unit can perform focus control by changing the refractive index by controlling the liquid lens or liquid crystal lens.

An example of a correction optical system is a variable cross cylinder lens.

The pattern light from the projection system 10 reflected by the optical multiplexer/demultiplexer 50 is projected onto the eye E via the optical system 51. The return light of the pattern light from the eye E to be examined passes through the optical system 51, is reflected by the optical multiplexer/demultiplexer 50, and is guided to the light receiving system 20.

(Light receiving system 20)
The light receiving system 20 includes an optical system 21 and an image sensor 22.

(Optical system 21)
The return light of the pattern light from the eye to be examined reflected by the optical multiplexer/demultiplexer 50 is incident on the optical system 21 . The optical system 21 includes an imaging lens that forms an image of the returned light on the detection surface of the image sensor 22. In some embodiments, optical system 21 further includes a relay optical system for relaying the return light.

(Image sensor 22)
The image sensor 22 functions as a pixelated light receiver. In this embodiment, image sensor 22 includes a CMOS image sensor. That is, the image sensor 22 includes a plurality of two-dimensionally arranged photodiodes (light receiving elements), a plurality of vertical signal lines, and a horizontal signal line. A plurality of vertical signal lines are provided for each vertical photodiode group. Each vertical signal line is selectively electrically connected to a group of photodiodes in which charges corresponding to light reception results are accumulated. The horizontal signal line is selectively electrically connected to the plurality of vertical signal lines. Thereby, the photodiode provided for each pixel accumulates charges corresponding to the result of receiving the returned light, and the accumulated charges are sequentially read out for each photodiode group in the horizontal direction, for example. That is, a voltage corresponding to the charge accumulated in each photodiode is supplied to the vertical signal line for each horizontal line. The plurality of vertical signal lines are selectively electrically connected to the horizontal signal line. By sequentially performing the readout operation for each horizontal line in the vertical direction, the light reception results of the plurality of photodiodes arranged two-dimensionally are read out.

The light-receiving surface (detection surface) of the image sensor 22 can be placed at a position that is optically substantially conjugate with the imaging site of the eye E to be examined (for example, the fundus of the eye, the anterior segment of the eye). That is, the light receiving surface of the image sensor 22 can be placed at a position that is optically substantially conjugate with the light source 11A.

Such readout control for the image sensor 22 can be executed under control from a control section, which will be described later.

The control unit can read the return light reception result from the image sensor 22 using a so-called rolling shutter method. Thereby, by performing readout control corresponding to the desired aperture shape, a received light image corresponding to the aperture shape is acquired. Such control is disclosed in, for example, US Pat. No. 8,237,835.

Specifically, by controlling the pattern light generating section 11, the control section generates a slit-shaped (line-shaped) pattern light extending at least in a direction substantially parallel to the direction corresponding to the aperture direction. They can be generated sequentially in a direction orthogonal to the direction. As disclosed in U.S. Pat. No. 8,237,835, etc., the control section reads the timing of pattern light generation by the pattern light generation section 11 and the reception result of the return light from the image sensor 22 in a rolling shutter method. Synchronize the timing. Thereby, it is possible to obtain an image of the eye to be examined with a simple configuration.

In some embodiments, the image sensor 22 includes a CCD (Charge-Coupled Device) image sensor.

When the image sensor 22 includes a CCD image sensor, the image sensor 22 includes a plurality of two-dimensionally arranged photodiodes, two or more vertical transfer registers, and a horizontal transfer register. Two or more vertical transfer registers are provided for each vertical photodiode group. The horizontal transfer register is selectively electrically connected to two or more vertical transfer registers. Thereby, the photodiode provided for each pixel accumulates charges corresponding to the result of receiving the returned light, and the accumulated charges are read out to, for example, a vertical transfer register. The plurality of vertical transfer registers are selectively electrically connected to the horizontal transfer registers. For example, a signal corresponding to a charge read out to one vertical transfer register is transferred to a horizontal transfer register, and the transferred signals are sequentially read out from the horizontal transfer register. By repeating this for a plurality of vertical transfer registers, the light reception results of a plurality of two-dimensionally arranged photodiodes are read out. When the image sensor 22 includes a CCD image sensor, an image corresponding to the result of receiving the returned light is acquired using a global shutter method or a rolling shutter method.

(Image processing unit 30)
The image processing unit 30 performs various image processing and analysis processing on the received light image obtained by the image sensor 22. Image processing includes noise removal processing for the received light image and brightness correction processing for making it easier to identify a predetermined region depicted in the received light image. The analysis processing includes processing for specifying a focus state, which will be described later, and processing for specifying control contents for performing focus control, which will be described later.

The image processing section 30 is capable of acquiring a received light image corresponding to an arbitrary aperture shape based on the received light results read out from the image sensor 22 using a rolling shutter method under the control of the control section. The image processing unit 30 can sequentially acquire received light images corresponding to the aperture shape and form an image of the eye E from the acquired plurality of received light images.

Note that when the image sensor 22 includes a CCD image sensor, the image processing unit 30 generates an image of the eye E based on the light reception results read out from the image sensor 22 using a global shutter method under the control of the control unit. It is possible to obtain

In some embodiments, optical system 21 includes an aperture stop located between the imaging lens and image sensor 22. In this case, the returned light that has passed through the aperture stop is imaged on the light receiving surface of the image sensor 22. Therefore, the image processing section 30 acquires a received light image corresponding to the aperture shape of the aperture diaphragm, based on the received light results read out from the image sensor 22 using the global shutter method under the control of the control section. is possible.

The image processing unit 30 includes a processor and implements the above functions by performing processing according to a program stored in a storage unit or the like.

In this specification, a "processor" refers to, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), a programmable logic device (for example, an S PLD (Simple Programmable Logic Device), CPLD (Complex It means a circuit such as a programmable logic device (programmable logic device) or FPGA (field programmable gate array). The processor realizes the functions according to the embodiment by, for example, reading and executing a program stored in a storage circuit or a storage device.

(Image output unit 40)
The image output unit 40 displays various information under the control of a control unit described below. For example, the image output unit 40 outputs the received light image obtained by the image processing unit 30.

The image output unit 40 includes a display device such as a flat panel display such as an LCD (Liquid Crystal Display).

(Other configurations)
In some embodiments, the ophthalmic device 1 further includes a fixation projection system. For example, the optical path of the fixation projection system is coupled to the optical path of the pattern light in the configuration of the optical system shown in FIG. The fixation projection system can present an internal fixation target or an external fixation target to the eye E to be examined. When presenting an internal fixation target to the eye E, the fixation projection system includes an LCD that displays the internal fixation target under the control of the control unit, and the fixation light flux output from the LCD is directed to the eye E. projected onto the fundus of the eye. The LCD is configured to be able to change the display position of the fixation target on the screen. By changing the display position of the fixation target on the LCD, it is possible to change the projected position of the fixation target on the fundus of the eye E to be examined. The display position of the fixation target on the LCD can be specified by the user using the operation unit.

In some embodiments, the fixation projection system includes, for example, a panel in which a plurality of LEDs are arranged instead of the LCD, and is configured to project the fixation target by lighting any of the LEDs. Ru.

Furthermore, since fixation can be induced by changing the projection position of the fixation target on the fundus of the eye E, it is also possible to change the observation direction.

In some embodiments, ophthalmic device 1 includes an alignment system. In some embodiments, the alignment system includes an XY alignment system and a Z alignment system. The XY alignment system is used to align the apparatus optical system and the subject's eye E in a direction intersecting the optical axis of the apparatus optical system (objective lens). The Z alignment system is used to align the apparatus optical system and the subject's eye E in the direction of the optical axis of the ophthalmological apparatus 1 (objective lens).

For example, the XY alignment system projects a bright spot (a bright spot in the infrared region or near-infrared region) onto the eye E to be examined. The image processing unit 30 acquires the anterior segment image of the subject's eye E onto which the bright spot is projected, and determines the displacement between the bright spot image depicted in the acquired anterior eye segment image and the alignment reference position. A control unit, which will be described later, uses a moving mechanism (not shown) to relatively move the device optical system and the eye E in a direction intersecting the direction of the optical axis so that the determined displacement is canceled.

For example, the Z alignment system projects alignment light in the infrared region or near-infrared region from a position off the optical axis of the apparatus optical system, and receives the alignment light reflected from the anterior segment of the eye E to be examined. The image processing unit 30 identifies the distance of the eye E to be examined relative to the apparatus optical system from the light receiving position of the alignment light, which changes depending on the distance of the eye E to be examined relative to the apparatus optical system. A control unit, which will be described later, relatively moves the device optical system and the eye E in the direction of the optical axis using a moving mechanism (not shown) so that the specified distance becomes a desired working distance.

In some embodiments, the functionality of the alignment system is accomplished by two or more anterior segment cameras positioned off-axis of the device optics. For example, as disclosed in Japanese Unexamined Patent Publication No. 2013-248376, the image processing unit 30 analyzes anterior segment images of the subject's eye E obtained substantially simultaneously with two or more anterior segment cameras. , the three-dimensional position of the eye E to be examined is specified using known trigonometry. The control unit, which will be described later, moves the device optical system using a moving mechanism (not shown) so that the optical axis of the device optical system substantially coincides with the axis of the eye E and the distance of the device optical system to the eye E becomes a predetermined working distance. The system and the eye E to be examined are moved relative to each other in three dimensions.

[Control system configuration]
Next, the control system of the ophthalmologic apparatus 1 will be explained.

FIG. 8 shows a block diagram of a configuration example of a control system of an ophthalmologic apparatus according to an embodiment. In FIG. 8, the same parts as in FIGS. 1 and 2 are denoted by the same reference numerals, and descriptions thereof will be omitted as appropriate.

As shown in FIG. 3, the control system of the ophthalmologic apparatus 1 is configured around a control section 100. Note that at least a part of the configuration of the control system may be included in the ophthalmologic apparatus 1.

(Control unit 100)
The control unit 100 controls each part of the ophthalmologic apparatus 1. Control unit 100 includes a main control unit 101 and a storage unit 102. The main control unit 101 includes a processor, and executes control processing for each unit of the ophthalmological apparatus 1 by executing processing according to a program stored in the storage unit 102.

(Main control unit 101)
The main control section 101 controls the projection system 10, the light receiving system 20, the image processing section 30, and the image output section 40.

Control of the projection system 10 includes control of the pattern light generating section 11. Control of the pattern light generator 11 includes control of the light source 11A and control of the spatial light modulator 11C. Control of the light source 11A includes switching the light source on or off (or the wavelength range of the light), and changing the light amount of the light source. Control of the spatial light modulator 11C includes spatial amplitude control, phase control, and polarization control for the light from the light source 11A, and temporal amplitude control, phase control, and polarization control for the light from the light source 11A. .

When the projection system 10 includes an optical scanner, the main control unit 101 can control the optical scanner. Control of the optical scanner includes control of the scan range (scan start position and scan end position) and scan speed.

Control of the light receiving system 20 includes control of the image sensor 22. Control of the image sensor 22 includes control of changing at least one of exposure tying, sensitivity, and frame rate, and readout control using a rolling shutter method or a global shutter method.

The control of the image processing unit 30 includes execution control of the above-mentioned image processing and execution control of analysis processing. Control of the image output unit 40 includes display control of the various information described above.

(Storage unit 102)
The storage unit 102 stores various computer programs and data. The computer program includes a calculation program and a control program for controlling the ophthalmologic apparatus 1.

(Operation unit 110)
The operation unit 110 includes an operation device or an input device. The operation unit 110 includes buttons and switches (for example, an operation handle, an operation knob, etc.) provided on the ophthalmologic apparatus 1, and operation devices (such as a mouse, a keyboard, etc.). Further, the operation unit 110 may include any operation device or input device such as a trackball, an operation panel, a switch, a button, a dial, or the like.

In some embodiments, at least a portion of the image output section 40 and the operation section 110 are configured integrally. As a specific example, the functions of the image output section 40 and the operation section 110 are realized by a touch screen.

The projection system 10 is an example of a "projection section" according to the embodiment. The control unit 100 that controls the light receiving system 20 and the image sensor 22 is an example of the “acquisition unit” according to the embodiment. The smoothing section 12 is an example of a "diffusion section" according to the embodiment.

[motion]
Next, the operation of the ophthalmologic apparatus 1 will be explained.

FIG. 9 shows a flow diagram of an example of the operation of the ophthalmologic apparatus 1 according to the embodiment. The storage unit 102 stores a computer program for implementing the processing shown in FIG. The main control unit 101 executes the processing shown in FIG. 9 by operating according to this computer program.

Here, alignment of the apparatus optical system with respect to the eye E to be examined is completed by an alignment system (not shown), and a fixation target is set to the fundus of the eye E to be examined so as to guide the eye to a desired fixation position by a fixation projection system (not shown). is projected.

(S1: Project pattern light)
First, the main controller 101 controls the pattern light generator 11 to generate a projected pattern light extending in a direction substantially parallel to the direction of the aperture corresponding to the shape of the aperture on the light receiving side.

The pattern light generated by the pattern light generating section 11 is smoothed by the smoothing section 12 in the slit direction (a direction substantially parallel to the direction corresponding to the aperture direction corresponding to the aperture shape on the light receiving side). The pattern light smoothed by the smoothing unit 12 is projected onto the eye E via the optical system 13, the optical multiplexer/demultiplexer 50, and the optical system 51.

(S2: Obtain a received light image)
Next, the main control unit 101 causes the image processing unit 30 to acquire a received light image.

Specifically, the pattern light projected onto the eye E by the projection system 10 is reflected by the eye E to be examined. The returned pattern light from the eye E passes through the optical system 51, the optical multiplexer/demultiplexer 50, and the optical system 21, and forms an image on the light receiving surface of the image sensor 22. The main control unit 101 reads out the result of the return light received by the image sensor 22 using a rolling shutter method corresponding to a predetermined aperture shape. The image processing unit 30 acquires a light reception image corresponding to the aperture shape based on the read light reception results.

(S3: Next?)
The main control unit 101 determines whether to project the next pattern of light onto the eye E to photograph a desired range in the fundus. For example, the main control unit 101 determines the shift order of the projection position (projection range) of the pattern light on the eye E based on the imaging range corresponding to the fundus image to be acquired and the predetermined projection shape of the pattern light. Decide in advance. The main control unit 101 determines whether to project the next pattern of light according to a predetermined shift order of projection positions.

In step S3, when it is determined that the next pattern of light is to be projected (S3: Y), the operation of the ophthalmologic apparatus 1 moves to step S14. On the other hand, when it is determined in step S3 that the next pattern of light is not to be projected (S3:N), the operation of the ophthalmologic apparatus 1 moves to step S15.

(S14: Change projection position)
When it is determined in step S13 that the next pattern light is to be projected (S13: Y), the main control unit 101 controls the pattern light generation unit 11 to project the next pattern light according to the predetermined projection position shift order. The projection shape (ie, the projection position and projection range) of the pattern light is changed so that the pattern light is projected at the projection position. For example, the main control unit 101 changes the projection shape of the pattern light so that the pattern light having the same projection shape as above is projected at a projection position shifted in a direction perpendicular to the slit direction. For example, the main control unit 101 controls the pattern light to project pattern light having the same projection shape as described above at a projection position shifted in the slit direction or a projection position shifted in the slit direction so that a part of the projection range overlaps with the projection position. Change the projected shape of.

Following step S14, the operation of the ophthalmologic apparatus 1 moves to step S11.

(S15: Synthesis)
When it is determined in step S13 that the next pattern light is not to be projected (S13: N), the main control unit 101 determines that the aperture positions (projection positions, projection ranges) are different from each other for the number of times the processes in steps S11 to S14 are repeated. By combining different received light images based on the above shift order, a fundus image for one frame of the eye E to be examined is formed.

This is the end of the operation of the ophthalmologic apparatus 1 (END).

<Modified example>
The configuration and control of the ophthalmological apparatus according to the embodiments are not limited to the above aspects. Modifications of the embodiment will be described below, focusing on the differences from the embodiment.

(First modification)
In the embodiment, a case has been described in which the pattern light generation unit 11 generates pattern light by spatially modulating the light from the light source using a light source and a non-light emitting device, but the configuration according to the embodiment is not limited to this. In this modification, the pattern light generating section includes a self-emitting device.

FIG. 10 shows a block diagram of a configuration example of a patterned light generation section according to a modification of the embodiment. The ophthalmological apparatus according to this modification includes a patterned light generating section 11a shown in FIG. 10 instead of the patterned light generating section 11.

The patterned light generating section 11a according to this modification includes a self-emitting device 120 and an optical system 121. The self-emissive device 120 realizes a function as a pixelated pattern light generator by generating light that is modulated for each pixel. Examples of the self-luminous device 120 include a cathode-ray tube (CRT), a plasma display panel (PDP), an organic EL (OEL), an LED, and an inorganic EL. electro-luminescence: IEL ), vacuum fluorescent display (VFD), and field emission display (FED).

The self-luminous device 120 can be placed at a position that is optically approximately conjugate with the imaging site of the eye E to be examined (for example, the fundus of the eye, the anterior segment of the eye). Optical system 121 includes a projection lens for projecting light spatially modulated by self-emissive device 120.

The operation of the ophthalmologic apparatus according to this modification is the same as that in the embodiment, so detailed explanation will be omitted.

[Action/Effect]
The functions and effects of the ophthalmological device according to the embodiment will be explained.

The ophthalmological apparatus (1) according to some embodiments includes a projection section (projection system 10) and an acquisition section (light receiving system 20 and control section 100 that controls the image sensor 22). The projection unit projects the pattern light onto the eye to be examined. The acquisition unit receives the return light of the pattern light from the eye to be examined, and acquires an image of the eye to be examined corresponding to the aperture shape based on the reception result of the return light. The projection section includes a pattern light generation section (11) and a diffusion section (smoothing section 12). The pattern light generating section generates pattern light in a projected shape extending at least in a direction substantially parallel to a first direction corresponding to an opening direction of the aperture shape. The diffusion section diffuses the pattern light.

According to such a configuration, pattern light having a projection shape extending at least in a direction substantially parallel to the first direction corresponding to the aperture direction of the aperture shape is diffused and projected onto the eye to be examined, and the pattern light is returned from the eye to be examined. An image of the eye to be examined corresponding to the aperture shape is acquired based on the light reception results. As a result, regardless of the arrangement of light-emitting pixels on the projection side and the arrangement of light-receiving pixels on the light-receiving side, it is possible to obtain images of the eye to be examined with a simple configuration that reduces image quality deterioration caused by uneven light reception. Become.

In some embodiments of the ophthalmological device, the diffusing section diffuses the patterned light in a first direction.

According to this configuration, the pattern light is diffused in the first direction, so regardless of the arrangement of the light-emitting pixels on the projection side and the arrangement of the light-receiving pixels on the light-receiving side, the problem caused by uneven light reception can be avoided with a simple configuration. It becomes possible to obtain an image of the eye to be examined with reduced image quality deterioration.

In the ophthalmological apparatus according to some embodiments, the diffusion unit diffuses the patterned light such that a diffusion range of the patterned light in the first direction is wider than a diffusion range of the patterned light in a second direction intersecting the first direction. .

According to such a configuration, it is possible to prevent image quality from deteriorating due to blurring due to diffusion in the second direction.

In the ophthalmological apparatus according to some embodiments, the diffusion unit spreads the patterned light so that the light reception unevenness reduction ratio of the patterned light is 0.285×Q or less, where Q is the pixel size ratio on the light receiving surface of the returned light. The light intensity distribution is smoothed.

With this configuration, regardless of the arrangement of the light-emitting pixels on the projection side and the arrangement of the light-receiving pixels on the light-receiving side, it is possible to prevent the deterioration of the image quality of the image of the subject's eye due to uneven light reception without increasing costs. You will be able to do this.

In the ophthalmological apparatus according to some embodiments, the diffusion unit spreads the patterned light so that the light reception unevenness reduction ratio of the patterned light is 0.76×Q or less, where Q is the pixel size ratio on the light receiving surface of the returned light. The light intensity distribution is smoothed.

With such a configuration, regardless of the arrangement of the light-emitting pixels on the projection side and the arrangement of the light-receiving pixels on the light-receiving side, it is possible to obtain a fundus image representing the morphology of the fundus of the eye to be examined at a low cost within the acceptable range of image quality. , it becomes possible to prevent deterioration of the image quality of the image of the eye to be examined without being affected by uneven light reception.

In some embodiments of the ophthalmological device, the diffusion section includes a diffusion filter disposed in the optical path of the patterned light.

According to such a configuration, it becomes possible to prevent deterioration in image quality due to uneven light reception with a simple configuration and at low cost.

In some embodiments of the ophthalmic device, the diffuser includes a birefringent plate disposed in the optical path of the patterned light.

According to such a configuration, it becomes possible to prevent deterioration in image quality due to uneven light reception with a simple configuration and at low cost.

In some embodiments of the ophthalmological device, the diffusing section includes a diffractive optical element disposed in the optical path of the patterned light.

According to such a configuration, it becomes possible to prevent deterioration in image quality due to uneven light reception with a simple configuration and at low cost.

In the ophthalmic apparatus according to some embodiments, the diffusing section includes an optical lens disposed in the optical path of the patterned light, and uses aberrations of the optical lens to diffuse the patterned light.

According to such a configuration, it becomes possible to prevent deterioration in image quality due to uneven light reception with a simple configuration and at low cost.

In the ophthalmological apparatus according to some embodiments, the optical axis of the optical lens is arranged to be inclined with respect to the optical path of the patterned light.

According to such a configuration, it becomes possible to prevent deterioration in image quality due to uneven light reception with a simple configuration and at low cost.

In the ophthalmological apparatus according to some embodiments, the diffusing section includes a plane-parallel plate arranged to be inclined with respect to the optical path of the patterned light.

According to such a configuration, it becomes possible to prevent deterioration in image quality due to uneven light reception with a simple configuration and at low cost.

In the ophthalmological apparatus according to some embodiments, the patterned light generation unit includes a light source (11A) and a spatial light modulator (11C) that generates patterned light by spatially modulating light from the light source. include.

According to such a configuration, it is possible to generate pattern light having a desired projection shape with a simple configuration and to prevent deterioration in image quality due to uneven light reception.

In the ophthalmological apparatus according to some embodiments, the acquisition unit includes an image sensor (22) that receives returned light, and acquires an image of the eye to be examined by reading out the result of receiving the returned light by the image sensor using a rolling shutter method. do.

According to such a configuration, it becomes possible to prevent deterioration in image quality due to uneven light reception with a simple configuration and at low cost.

The embodiment shown above or its modification example is only an example for implementing the present invention. Those who wish to implement this invention can make arbitrary modifications, omissions, additions, etc. within the scope of the gist of this invention.

In the above embodiments or variations thereof, the ophthalmologic apparatus may have any function usable in the ophthalmology field, such as an axial length measurement function, an intraocular pressure measurement function, an optical coherence tomography (OCT) function, or an ultrasound examination function. It may have a function. Note that the axial length measurement function is realized by an optical coherence tomography device or the like. In addition, the axial length measurement function projects light onto the eye to be examined and detects the return light from the fundus while adjusting the position of the optical system in the Z direction (anterior-posterior direction) with respect to the eye to be examined. The axial length of the eye may be measured. The intraocular pressure measurement function is realized by a tonometer or the like. The OCT function is realized by optical coherence tomography or the like. The ultrasonic testing function is realized by an ultrasonic diagnostic device or the like. Further, the present invention can also be applied to a device (multifunction device) that has two or more of these functions.

In some embodiments, a program is provided for causing a computer to execute the method for controlling an ophthalmological apparatus described above. Such a program can be stored in any computer-readable recording medium. Examples of this recording medium include semiconductor memory, optical disks, magneto-optical disks (CD-ROM/DVD-RAM/DVD-ROM/MO, etc.), magnetic storage media (hard disks/floppy (registered trademark) disks/ZIP, etc.), etc. It is possible to use It is also possible to send and receive this program via a network such as the Internet or LAN.

1 Ophthalmological apparatus 10 Projection system 11, 11a Pattern light generating section 11A Light source 11C Spatial light modulator 12 Smoothing section 11B, 13, 21, 51, 121 Optical system 20 Light receiving system 22 Image sensor 30 Image processing section 40 Image output section 50 Optical multiplexer/demultiplexer 100 Control section 101 Main control section 102 Storage section 110 Operation section 120 Self-luminous device E Eye to be examined

Claims (10)

A slit-shaped pattern of light formed in a slit direction corresponding to the aperture direction of the light-receiving side aperture is projected onto the eye to be examined, and a slit-like pattern of light is projected onto the eye to be examined, and the light is formed in a pattern corresponding to the shape of the aperture on the light-receiving surface of the image sensor provided on the light-receiving side. An ophthalmological apparatus that reads out a reception result of the return light of the patterned light from the eye to be examined from an image sensor using a rolling shutter method,
a projection unit that projects the pattern light onto the eye to be examined;
an acquisition unit that receives the returned light and acquires an image of the eye to be examined corresponding to the shape of the aperture on the light receiving surface based on the reception result of the returned light;
including;
The projection section is
a patterned light generating section that includes a plurality of light emitting pixels arranged two-dimensionally and generates the patterned light;
a diffusion unit that diffuses the pattern light such that a diffusion range of the pattern light in the slit direction is wider than a diffusion range of the pattern light in a direction crossing the slit direction;
ophthalmological equipment including; The image sensor includes a plurality of light receiving pixels arranged two-dimensionally,
When the light-emitting pixel period of the light-emitting pixels arranged in the slit direction is Λi, and the light-receiving pixel period of the light-receiving pixels arranged in the aperture direction is Λd, the pixel size ratio Q on the light-receiving surface of the returned light is ( Λd/Λi),
The aperture ratio in the aperture direction in the image sensor is Rd, the aperture ratio in the slit direction in the projection section is Ri, the inter-pixel gap between light emitting pixels arranged in the slit direction is Gi, and the aperture ratio in the light receiving pixel is Rd. When the size in the aperture direction is Pd, the light receiving unevenness reduction ratio of the patterned light is (1/2 x RD x Q ×(1-Rd)/Ri), RD is 0.03, and Rd and Ri are 0.05,
The ophthalmologic apparatus according to claim 1, wherein the diffusion section smoothes the light amount distribution of the pattern light in the slit direction so that the light reception unevenness reduction ratio is 0.285×Q or less. The image sensor includes a plurality of light receiving pixels arranged two-dimensionally,
When the light-emitting pixel period of the light-emitting pixels arranged in the slit direction is Λi, and the light-receiving pixel period of the light-receiving pixels arranged in the aperture direction is Λd, the pixel size ratio Q on the light-receiving surface of the returned light is ( Λd/Λi),
The aperture ratio in the aperture direction in the image sensor is Rd, the aperture ratio in the slit direction in the projection section is Ri, the inter-pixel gap between light emitting pixels arranged in the slit direction is Gi, and the aperture ratio in the light receiving pixel is Rd. When the size in the aperture direction is Pd, the light receiving unevenness reduction ratio of the patterned light is (1/2 x RD x Q ×(1-Rd)/Ri), RD is 0.08, and Rd and Ri are 0.05,
The diffusion unit smoothes the light amount distribution of the patterned light in the slit direction so that the reception unevenness reduction ratio of the patterned light is 0.76×Q or less. Ophthalmology equipment. The ophthalmologic apparatus according to any one of claims 1 to 3, wherein the diffusion section includes a diffusion filter placed in the optical path of the patterned light. The ophthalmologic apparatus according to any one of claims 1 to 4, wherein the diffusion section includes a birefringence plate disposed in the optical path of the patterned light. The ophthalmologic apparatus according to any one of claims 1 to 5, wherein the diffusing section includes a diffractive optical element disposed in the optical path of the patterned light. Any one of claims 1 to 6, wherein the diffusion section includes an optical lens disposed on the optical path of the patterned light, and diffuses the patterned light using an aberration of the optical lens. The ophthalmological device described in . The ophthalmologic apparatus according to claim 7, wherein the optical axis of the optical lens is arranged to be inclined with respect to the optical path of the pattern light. The ophthalmologic apparatus according to any one of claims 1 to 8, wherein the diffusion section includes a parallel plane plate arranged to be inclined with respect to the optical path of the patterned light. The pattern light generating section is
a light source and
a spatial light modulator that generates the patterned light by spatially modulating light from the light source;
The ophthalmological device according to any one of claims 1 to 9, characterized in that it comprises:

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