Black spot plate for ophthalmic equipment and method for manufacturing the same, ophthalmic equipment

Abstract

To provide a black spot plate for ophthalmologic apparatus manufactured by a further simple method and capable of suppressing reflection at an interface between a substrate or another coating layer and the black point plate, and ophthalmologic apparatus using the black spot plate for preventing occurrence of ghost.SOLUTION: A black spot plate for ophthalmologic apparatus comprising a substrate layer, an antireflection layer composed of at least one layer provided on the substrate layer, and a light shielding layer provided as a small black spot on the antireflection layer, includes a first refractive index matching layer formed of a dielectric layer for preventing reflection of incident light from the antireflection layer, provided between the antireflection layer and the light shielding layer, and a second refractive index matching layer formed of a dielectric layer for preventing reflection of incident light from air, provided on the light shielding layer.SELECTED DRAWING: Figure 6

Description

【Technical Field】 【0001】 The present invention relates to a black dot plate for an ophthalmic device used for observing, photographing, etc. of an eye to be examined, and an ophthalmic device using the same. 【Background Art】 【0002】 In an ophthalmic device such as a fundus camera, there are an illumination system that projects illumination light from an illumination light source to an eye to be examined through an objective lens, and an observation system and a photographing system that guide the reflected light of the illumination light from the eye to be examined to an observation means and a photographing means through the objective lens and a photographing aperture, respectively. 【0003】 In such an ophthalmic device, the reflected light from the surface of the objective lens facing the eye to be examined is mixed into the observation system and the photographing system as harmful light, causing flare and ghost, and making it impossible to clearly observe and photograph the fundus. 【0004】 Conventionally, various techniques have been developed to remove such harmful light. For example, Patent Document 1 discloses an ophthalmic device provided with a black dot plate in which a black paint layer is formed as small black dots between a plurality of stacked substrates that can transmit light. According to this black dot plate, black dots overlap in the vicinity of the center when viewed from the optical axis direction of the illumination light source, and the illumination light in this portion is blocked. Thereby, the occurrence of ghosts and the like in the vicinity of the center of the objective lens can be prevented. 【Prior Art Documents】 【Patent Documents】 【0005】 【Patent Document 1】 Japanese Patent No. 3576645 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0006】 However, conventional methods for manufacturing black dot plates involved using chemical means such as etching and physical means such as grinding to form tiny holes on the substrate for filling with the black paint for the black dots. 【0007】 The following problems arose in the formation of micropores using these methods. First, there were design constraints associated with the above-mentioned chemical and physical means, making it difficult to achieve uniform depth across the entire micropore. In particular, with chemical methods, attempting to deepen the micropores beyond a certain depth required prolonged dissolution, which sometimes resulted in unevenness at the bottom of the micropores, making uniformity impossible. Furthermore, there was variability in micropore formation during the production of multiple black dot plates, resulting in poor reproducibility. In addition, measuring the depth after micropore formation was time-consuming. Moreover, because the black paint was directly filled into the micropores of the substrate, depending on the refractive index difference between the two, incident light from the substrate side was reflected at the substrate-black paint layer interface. 【0008】 Therefore, the present invention aims to provide a black dot plate for ophthalmic devices and an ophthalmic device using the same, which can be manufactured by a simpler method and can suppress reflection at the interface between the substrate or other coating layer and the black dot plate, in order to prevent the occurrence of flare and ghosting. [Means for solving the problem] 【0009】 To achieve this objective, the invention described in claim 1 is a black dot plate for an ophthalmic device having a substrate layer, an anti-reflective layer consisting of at least one layer provided on the substrate layer, and a light-shielding layer provided on the anti-reflective layer as a small black dot, characterized in that a first refractive index matching layer made of a dielectric layer that prevents reflection of incident light from the anti-reflective layer is provided between the anti-reflective layer and the light-shielding layer, and a second refractive index matching layer made of a dielectric layer that prevents reflection of incident light from air is provided on the light-shielding layer. 【0010】 The invention described in claim 2 is a black dot plate for an ophthalmic device having a substrate layer, a light-shielding layer provided on the substrate layer as small black dots, and an anti-reflective layer consisting of at least one layer provided on the substrate layer covering the light-shielding layer, characterized in that a first refractive index matching layer made of a dielectric layer is provided between the substrate layer and the light-shielding layer to prevent reflection of incident light from the substrate layer, and a second refractive index matching layer made of a dielectric layer is provided between the light-shielding layer and the anti-reflective layer to prevent reflection of incident light from the anti-reflective layer. 【0011】 The invention described in claim 3 is a black dot plate for an ophthalmic device, comprising a substrate layer, a light-shielding layer provided on the substrate layer as small black dots, an adhesive layer provided on the substrate layer covering the light-shielding layer, and another substrate layer provided on the adhesive layer, wherein a first refractive index matching layer made of a dielectric layer to prevent reflection of incident light from the substrate layer is provided between the substrate layer and the light-shielding layer, and a second refractive index matching layer made of a dielectric layer to prevent reflection of incident light from the adhesive layer is provided between the light-shielding layer and the adhesive layer. 【0012】 The invention described in claim 4 is characterized in that, in the invention described in any one of claims 1 to 3, a thin metal layer made of the same material as the light-shielding layer is provided in at least one of the refractive index matching layers. 【0013】 The invention described in claim 5 is a method for manufacturing a black spot plate for an ophthalmic device as described in claim 1, characterized in that the anti-reflective layer is formed on the substrate layer, a masking layer having a desired pattern is formed on the anti-reflective layer, then a dielectric layer constituting the first refractive index matching layer, the light-shielding layer, and a dielectric layer constituting the second refractive index matching layer are formed, and the masking layer is removed. 【0014】 The invention described in claim 6 is a method for manufacturing a black spot plate for an ophthalmic device as described in claim 2, characterized in that, after forming a masking layer having a desired pattern on the substrate layer, a dielectric layer constituting the first refractive index matching layer, the light-shielding layer, and a dielectric layer constituting the second refractive index matching layer are formed, the masking layer is removed, and the anti-reflective layer is formed on the substrate layer so as to cover the first refractive index matching layer, the light-shielding layer, and the second refractive index matching layer. 【0015】 The invention described in claim 7 is a method for manufacturing a black spot plate for an ophthalmic device as described in claim 3, characterized in that, after forming a masking layer having a desired pattern on the substrate layer, a dielectric layer constituting the first refractive index matching layer, a light-shielding layer, and a dielectric layer constituting the second refractive index matching layer are formed, the masking layer is removed, the adhesive layer is formed on the substrate layer so as to cover the first refractive index matching layer, the light-shielding layer, and the second refractive index matching layer, and the other substrate layer is bonded onto the adhesive layer. 【0016】 The invention described in claim 8 is characterized in that, in the invention described in any one of claims 5 to 7, at least one thin metal layer is formed in the dielectric layer when forming the first refractive index matching layer and / or the second refractive index matching layer. 【0017】 The invention described in claim 9 is characterized in that, in the invention described in any one of claims 5 to 7, instead of forming a masking layer having the desired pattern, forming the refractive index matching layer and the light-shielding layer, and then removing the masking layer, the refractive index matching layer and the light-shielding layer are formed over the entire surface and then the unnecessary portions are removed to obtain the desired pattern. 【0018】 The invention according to claim 10 is an ophthalmic device comprising an illumination system that projects illumination light from an illumination light source onto an eye to be examined through a pinhole mirror to illuminate the eye to be examined, and a photographing system having a photographing aperture provided in an optical path for photographing the eye to be examined, wherein the illumination system and the photographing system have a common objective lens disposed between the eye to be examined and the pinhole mirror, the illumination system has a black dot plate for an ophthalmic device according to any one of claims 1 to 4, and when considering the lens surface of the objective lens as a reflecting surface, a position where an image of the aperture of the photographing aperture is formed and the light shielding layer are provided conjugately via the reflecting surface so that the image of the aperture of the photographing aperture is covered by the light shielding layer. 【Advantages of the Invention】 【0019】 According to the present invention, when forming the light shielding layer corresponding to the small black dots of the prior art, instead of providing minute holes in a substrate or an antireflection layer, a light shielding layer is formed in a desired pattern using a masking technique. Therefore, there are no design restrictions on dimensions such as the width and thickness of the light shielding layer, the thickness is uniform over the entire surface, the reproducibility is high even when manufactured multiple times, and there is no need to measure the dimensions after manufacturing. Further, since the light shielding layer is formed via a first refractive index matching layer on the substrate layer and the antireflection layer, reflection of incident light from the substrate side between the substrate and the light shielding layer is suppressed. Since a second refractive index matching layer is formed between the opposite side of the light shielding layer from the substrate layer, that is, between the antireflection layer, the adhesive layer, and air, reflection of incident light from this side is also suppressed simultaneously. 【Brief Description of the Drawings】 【0020】 [Figure 1] It is a schematic diagram of a conventional ophthalmic device having no black dot plate. [Figure 2] It is a photographic image showing a central ghost. [Figure 3] It is a schematic diagram of a conventional ophthalmic device having a black dot plate. [Figure 4] It is a photographic image showing a black dot shadow due to insertion of a black dot plate. [Figure 5] It is a schematic cross-sectional view of a conventional black dot plate. [Figure 6]It is a schematic cross-sectional view of a black dot plate according to the first embodiment of the present invention. [Figure 7] It is a schematic cross-sectional view of a black dot plate according to the second embodiment of the present invention. [Figure 8] It is a schematic cross-sectional view of a black dot plate according to the third embodiment of the present invention. [Figure 9] It is a graph showing the transmittance, surface reflectance, and back surface reflectance of the black dot plate in the example. 【Embodiments for Carrying Out the Invention】 【0021】 Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 shows an outline of an optical system of an ophthalmic device 100 such as a fundus camera targeted by the present invention. First, as an illumination optical system of the ophthalmic device 100, from the upstream side, an observation illumination light source 101, a lens 102, a hole mirror 103 having a hole portion (aperture) 103a, and an objective lens 104 are provided. Reference numeral 200 denotes the eye to be examined. The light irradiated from the illumination light source 101 is reflected by the hole mirror 103 through the lens 102 and irradiated onto the retina of the eye to be examined through the objective lens 104 as indicated by the thin line A. 【0022】 Next, as an observation / imaging optical system, it reaches the sensor 106, the lens 105, the hole mirror 103, the objective lens 104, and the eye to be examined 200. The light irradiated onto the retina of the eye to be examined 200 from the illumination light source 101 passes through the hole portion 103a of the hole mirror 103 through the objective lens 104, passes through the lens 105, and is received by the sensor 106, and is provided as data of a fundus image to an observation means not shown. 【0023】 Here, at the surface 104a of the objective lens 104, reflected light is generated at the interface and reaches the sensor 106 along the path indicated by the thick line C, and is observed as a ghost as shown in FIG. 2. The black dot plate of the present invention is used to prevent this. 【0024】 Next, Figure 3 shows a schematic diagram of the ophthalmic apparatus 100 in Figure 1 with a black spot plate inserted. In the illumination optical system, the black spot plate 107 is inserted between the illumination light source 101 and the lens 102. Light from the illumination light source 101 is irradiated as shown by the thin line A, but the black spot plate 107 casts a shadow, and the illumination light near the center of the optical axis is shielded as shown by the thick line C2. The illumination light is then reflected by the aperture mirror 103, shielding the area near the center of the surface of the objective lens surface 104a as shown by C2. This prevents reflected light from being generated on the objective lens surface 104a, and no ghosting is detected by the sensor 106. However, depending on the size of the black spot, or if the shielded area becomes large, it may affect the observation and imaging system, and another problem may arise in which black spot shadows appear in the fundus image as shown in Figure 4. 【0025】 Figure 5 shows a schematic cross-sectional view of the conventional black spot plate described above. (a) is a plan view, and (b) is a side cross-sectional view. The conventional black spot plate 10 has a substrate layer 11 made of glass or the like, a light-shielding layer 12 made by filling micropores on the substrate layer 11 with black paint, and an anti-reflective layer 13 formed on the same. As described above, in the conventional black spot plate 10, micropores were formed chemically or physically in the substrate layer, which had design constraints, made it difficult to make the depth uniform throughout the entire micropore area, resulted in poor reproducibility when manufacturing multiple black spot plates, and also required time to measure the depth after the formation of the micropores. Furthermore, because the black paint was directly filled into the micropores, depending on the refractive index difference between the two, incident light from the substrate side was reflected at the substrate-black paint layer interface. 【0026】 The present invention solves these problems and will be described in detail below with reference to the figures. <First Embodiment> Figure 6(a) is a schematic cross-sectional view of a black dot plate 20 according to the first embodiment of the present invention. The black dot plate 20 has a substrate layer 21 made of a transparent material such as glass, and an anti-reflective layer 22 is provided on its surface. The anti-reflective layer 22 is selected to have a refractive index that prevents reflection between the substrate layer 21 and the air. A black dot layer 23 is provided on the surface of the anti-reflective layer 22. The above is the basic configuration of the first embodiment. Note that in Figure 6(a), the black dot layer 23 is shown as a convex portion, but this is an exaggeration of the length in the vertical direction of the black dot layer 23, and the actual black dot layer 23 is a thin layer with a thickness on the order of nanometers. 【0027】 A detailed close-up of the black spot plate of the first embodiment, as shown in Figure 6(b), reveals that the black spot layer 23 has a light-blocking layer 24 that is opaque to light, and a first refractive index matching layer 25 made of a dielectric layer 25a between the light-blocking layer 24 and the anti-reflective layer 22. The black spot layer 23 also has a second refractive index matching layer 26 made of a dielectric layer 26a between the light-blocking layer 24 and the surrounding atmosphere (air). 【0028】 The refractive index of the first refractive index matching layer 25 is selected by considering the refractive index of the anti-reflective layer 22 and the refractive index of the light-shielding layer 24, so that incident light from below the drawing does not reflect at the interface between the anti-reflective layer 22 and the light-shielding layer 24. Similarly, the refractive index of the second refractive index matching layer 26 is selected by considering the refractive index of air and the refractive index of the light-shielding layer 24, so that incident light from above the drawing does not reflect at the interface between the air and the light-shielding layer 24. 【0029】 The thickness of each layer in the black spot layer 23 is described below. The light-shielding layer 24 needs to be opaque to light, and only needs to be thick enough to block light. It is usually deposited to a thickness of 100 nm or more. The first refractive index matching layer 25 and the second refractive index matching layer 26 may consist of single layers of dielectric layers 25a and 26a as in this embodiment, or they may consist of multiple layers as in the modified examples described later, but they are deposited in the range of 85 to 500 nm. 【0030】 The material of the light-shielding layer 24 is preferably a metal, and in particular, Cr, Ni, Ti, Fe, Si, Ta, Nb, Zr, Mo, W, etc. The material of the dielectric layers 25a and 26a constituting the first refractive index matching layer 25 and the second refractive index matching layer 26 is preferably an oxide system such as SiO2, NbO2, Y2O3, Al2O3, TiO2, Ta2O5, ZrO2, HfO2, or a fluoride system such as MgF2. In Figure 6(b), the dielectric layers 25a and 26a are shown as single layers each, but the first refractive index matching layer 25 and the second refractive index matching layer 26 may be constructed by selecting two or more of these compounds and laminating two or more layers. 【0031】 The manufacturing method for the black dot plate 20a described above is as follows. Specifically, an anti-reflective layer 22 is formed on a transparent substrate layer 21 such as glass by a known method. Subsequently, a masking layer (not shown) with a desired pattern is formed on the anti-reflective layer 22 by a known method of masking, such as mask deposition (forming a film by covering it with a perforated mask) or lift-off deposition. 【0032】 On this masking layer, a known film deposition method such as vapor deposition or sputtering is performed using the material of one or more dielectric layers 25a constituting the first refractive index matching layer 25 to deposit the first refractive index matching layer 25 within a desired pattern of the masking layer and to a desired thickness. Subsequently, a film deposition is performed similarly using the material of the light-shielding layer 24 and the material of one or more dielectric layers 26a constituting the second refractive index matching layer 26. Finally, the masking layer is removed. In this way, the black dot plate 20a of the first embodiment shown in Figure 6(b) is obtained. 【0033】 Alternatively, photolithography can be used instead of masking technology. Specifically, the first refractive index matching layer 25, the light-shielding layer 24, and the second refractive index matching layer 26 are deposited over the entire surface of the anti-reflective layer 22 to the desired thickness. Subsequently, patterning and etching are performed using photolithography or similar methods to remove unwanted portions. 【0034】 According to the present invention's method for manufacturing black dot plates, since film formation is performed on a smooth surface without drilling holes, a uniform thickness can be obtained across the entire surface, the thickness can be controlled to the order of nanometers, and furthermore, reproducibility is high even when manufacturing multiple black dot plates. 【0035】 <First Embodiment, Modification Example 1> Figure 6(c) shows a modified example of the first embodiment. In the black dot plate 20b of this modified example, thin metal layers 25b and 26b made of the same material (metal) as the material constituting the light-shielding layer 24 are formed in the layers of the first refractive index matching layer 25 and the second refractive index matching layer 26. Specifically, in the first refractive index matching layer 25, the dielectric layer 25a, the thin metal layer 25b, and the dielectric layer 25a are stacked in that order, and in the second refractive index matching layer 26, the dielectric layer 26a, the thin metal layer 26b, and the dielectric layer 26a are stacked in that order. 【0036】 The metal thin layer may be formed on only one of the first refractive index matching layer 25 or the second refractive index matching layer 26. The thickness of the metal thin layers 25b and 26b is in the range of approximately 10 to 200 nm. 【0037】 According to this modified example of the first embodiment, by inserting a thin layer with an absorbing effect into the refractive index matching layer, light that penetrates the film can be absorbed and attenuated. This has the effect of reducing reflected light not only due to interference effects but also due to absorption effects. 【0038】 The manufacturing method for the black dot plate 20b involves the following steps in the masking process described above: depositing the dielectric layer 25a material, the metal thin layer 25b material, the dielectric layer 25a material (these three layers constitute the first refractive index matching layer 25), the light-shielding layer 24 material, the dielectric layer 26a material, the metal thin layer 26b material, and the dielectric layer 26a material (these three layers constitute the second refractive index matching layer 26) within the desired pattern of the masking layer. Subsequently, the masking layer is removed. Alternatively, if photolithography is used, instead of the masking process, the dielectric layer 25a, metal thin layer 25b, dielectric layer 25a, light-shielding layer 24, dielectric layer 26a, metal thin layer 26b, and dielectric layer 26a are deposited over the entire surface in that order, and the unwanted portions are removed. In this way, the black dot plate 20b shown in Figure 6(c) is obtained. 【0039】 <First Embodiment, Modification Example 2> Figure 6(d) shows a modified example 2 of the first embodiment. In the black dot plate 20c of this modified example, two layers each of thin metal layers 25a and 26a, made of the same type of material (metal) as the material constituting the light-shielding layer 24, are formed in the first refractive index matching layer 25 and the second refractive index matching layer 26, similar to the black dot plate 20b described above. Note that Figure 6(d) is just one example, and either the first refractive index matching layer 25 or the second refractive index matching layer 26 may have two thin metal layers and the other may have zero to one layer. Alternatively, three or more thin metal layers may be provided in either or both of the first refractive index matching layer 25 and the second refractive index matching layer 26. 【0040】 According to this modified example of the first embodiment, by making the refractive index matching layer a multilayer structure, it becomes possible to broaden the anti-reflective band and further reduce the reflectivity. 【0041】 The manufacturing method for the black dot plate 20c is the same as that for the black dot plate 20b. In the masking step, films are sequentially deposited within the desired pattern of the masking layer in the desired layer order. Subsequently, the masking layer is removed. In this way, the black dot plate 20c shown in Figure 6(d) is obtained. 【0042】 <Second Embodiment> Figure 7(a) is a schematic cross-sectional view of a black dot plate 30 according to a second embodiment of the present invention. The black dot plate 30 has a substrate layer 31 made of a transparent material such as glass, and a black dot layer 33 is provided on its surface. An anti-reflective layer 32 is provided on the substrate layer 31 so as to cover the black dot layer 33. The anti-reflective layer 32 is selected to have a refractive index that prevents reflection between the substrate layer 31 and the air. The above is the basic configuration of the second embodiment. 【0043】 A detailed close-up of the black dot plate of the second embodiment, as shown in Figure 7(b), reveals that the black dot layer 33 has a light-blocking layer 34 that is opaque to light, and a first refractive index matching layer 35 made of a dielectric layer 35a between the light-blocking layer 34 and the substrate layer 31. The black dot layer 23 also has a second refractive index matching layer 36 made of a dielectric layer 36a between the light-blocking layer 34 and the surrounding anti-reflective layer 32 that covers it. 【0044】 The refractive index of the first refractive index matching layer 35 is selected by considering the refractive index of the substrate layer 31 and the refractive index of the light-shielding layer 34, so that incident light from below the drawing does not reflect at the interface between the substrate layer 31 and the light-shielding layer 34. Similarly, the refractive index of the second refractive index matching layer 36 is selected by considering the refractive index of the anti-reflective layer 32 and the refractive index of the light-shielding layer 34, so that incident light from above the drawing does not reflect at the interface between the anti-reflective layer 32 and the light-shielding layer 34. 【0045】 The manufacturing method for the black dot plate 30a described above is as follows. Specifically, a masking layer (not shown) with a desired pattern is formed on a transparent substrate layer 31 such as glass by a known method of masking, such as mask deposition (forming a film by covering it with a perforated mask) or lift-off deposition. 【0046】 On this masking layer, a known film deposition method such as vapor deposition or sputtering is performed using the material of one or more dielectric layers 35a constituting the first refractive index matching layer 35 to deposit the first refractive index matching layer 35 within a desired pattern of the masking layer and to a desired thickness. Subsequently, a similar film deposition is performed using the material of the light-shielding layer 34 and the material of one or more dielectric layers 36a constituting the second refractive index matching layer 36. Finally, the masking layer is removed. Alternatively, the aforementioned photolithography can be used instead of the masking technique. Subsequently, an anti-reflective layer 32 is deposited using a known method to cover the black dot layer 33. In this way, the black dot plate 30a of the second embodiment shown in Figure 7(b) is obtained. 【0047】 <Second Embodiment, Modification Example 1> Figure 7(c) shows a modified example of the second embodiment. In the black dot plate 30b of this modified example, a thin metal layer 35b and a metal 36b, made of the same type of material (metal) as the material constituting the light-shielding layer 34, are formed in at least one of the first refractive index matching layer 35 and the second refractive index matching layer 36. Note that the thin layer may be formed in only one of the layers. The manufacturing process for the black dot layer 33 of the black dot plate 30b of this modified example is the same as the masking process in the manufacturing process for the black dot layer 23 of the black dot plate 20b of the modified example of the first embodiment, so the explanation is omitted. 【0048】 <Second Embodiment, Modification Example 2> Figure 7(d) shows a modified example of the second embodiment. In the black dot plate 30c of this modified example, similar to the black dot plate 30b described above, two layers each of thin metal layers 35b and metal 36b, made of the same type of material (metal) as the material constituting the light-shielding layer 34, are formed in at least one of the first refractive index matching layer 35 and the second refractive index matching layer 36. The manufacturing process for the black dot layer 33 of the black dot plate 30c of this modified example is the same as the masking process in the manufacturing process for the black dot layer 23 of the black dot plate 20c of the modified example of the first embodiment, so the explanation is omitted. Similarly, the thin metal layers are not limited to a configuration in which two layers each are provided in the first refractive index matching layer 35 and the second refractive index matching layer 36. 【0049】 <Third Embodiment> Figure 8(a) is a schematic cross-sectional view of a black dot plate 40 according to the third embodiment of the present invention. The black dot plate 40 has a substrate layer 41 made of a transparent material such as glass, and a black dot layer 43 is provided on its surface. An adhesive layer 42 is provided on the substrate layer 41 so as to cover the black dot layer 43. Furthermore, another substrate layer 47 is bonded to the adhesive layer 42. The adhesive layer 42 and the other substrate layer 47 are selected to have refractive indices that prevent reflection between the substrate layer 41 and the air. The above is the basic configuration of the third embodiment. 【0050】 A detailed close-up of the black dot plate of the third embodiment, as shown in Figure 8(b), reveals that the black dot layer 43 has a light-blocking layer 44 that is opaque to light, and a first refractive index matching layer 45 made of a dielectric layer 45a between the light-blocking layer 44 and the substrate layer 41. The black dot layer 43 also has a second refractive index matching layer 46 made of a dielectric layer 45a between the light-blocking layer 44 and the surrounding adhesive layer 42 that covers it. 【0051】 The refractive index of the first refractive index matching layer 45 is selected by considering the refractive index of the substrate layer 41 and the refractive index of the light-shielding layer 44, so that incident light from below the drawing does not reflect at the interface between the substrate layer 41 and the light-shielding layer 44. Similarly, the refractive index of the second refractive index matching layer 46 is selected by considering the refractive index of the adhesive layer 42 and the refractive index of the light-shielding layer 44, so that incident light from above the drawing does not reflect at the interface between the adhesive layer 42 and the light-shielding layer 44. 【0052】 The manufacturing method for the black dot plate 40a described above is as follows. Specifically, a masking layer (not shown) with a desired pattern is formed on a transparent substrate layer 41 such as glass by a known method of masking, such as mask deposition (forming a film by covering it with a perforated mask) or lift-off deposition. 【0053】 On this masking layer, a known film deposition method such as vapor deposition or sputtering is performed using the material of one or more dielectric layers 45a constituting the first refractive index matching layer 45 to deposit the first refractive index matching layer 45 within a desired pattern of the masking layer and to a desired thickness. Subsequently, a film deposition is performed similarly using the material of the light-shielding layer 44 and the material of one or more dielectric layers 46a constituting the second refractive index matching layer 46. Finally, the masking layer is removed. Alternatively, the aforementioned photolithography can be used instead of the masking technique. Subsequently, an adhesive layer 42 is deposited using a known method so as to cover the black dot layer 43. Finally, the other substrate layer 47 is attached onto the adhesive layer 42. In this way, the black dot plate 40a of the third embodiment shown in Figure 8(b) is obtained. 【0054】 <Third Embodiment, Modification Example 1> Figure 8(c) shows a modified example of the third embodiment. In the black dot plate 40b of this modified example, metal thin layers 35b and 36b, made of the same material (metal) as the material constituting the light-shielding layer 44, are formed in at least one of the first refractive index matching layer 45 and the second refractive index matching layer 46. Note that the thin layers may be formed in only one of them. The manufacturing process for the black dot layer 43 of the black dot plate 40b of this modified example is the same as the masking process in the manufacturing process for the black dot layer 23 of the black dot plate 20b of the modified example of the first embodiment, so the explanation is omitted. 【0055】 <Third Embodiment, Modification Example 2> Figure 8(d) shows a modified example of the third embodiment. In the black dot plate 40c of this modified example, similar to the black dot plate 40b described above, two layers each of thin metal layers 35b and metal 36b, made of the same type of material (metal) as the material constituting the light-shielding layer 44, are formed in at least one of the first refractive index matching layer 45 and the second refractive index matching layer 46. The manufacturing process for the black dot layer 43 of the black dot plate 40c of this modified example is the same as the masking process in the manufacturing process for the black dot layer 23 of the black dot plate 20c of the modified example of the first embodiment, so the explanation is omitted. Similarly, the thin metal layers are not limited to a configuration in which two layers each are provided in the first refractive index matching layer 45 and the second refractive index matching layer 46. 【0056】 As described above, the black dot plate for ophthalmic devices of the present invention is characterized by its method of manufacturing the black dot layer, resulting in improved design accuracy of the black dot layer. Furthermore, since a refractive index matching layer is provided at the interface between the light-shielding layer and other layers in the black dot layer, the transmittance and reflectance performance are improved. For example, as shown in Figure 3, it can be used by replacing the black dot plate in ophthalmic devices such as fundus cameras that use conventional black dot plates. [Examples] 【0057】 The following is an example of a manufacturing process. A black dot plate for ophthalmic equipment was fabricated using the configuration of the black dot plate 20b of the modified example 1 of the first embodiment shown in Figure 6(c). The specifications of each layer are shown in Table 1. 【0058】 [Table 1] 【0059】 Figure 9 shows a graph of the optical properties of the above manufacturing example. As shown in the graph, the transmittance is almost 0, and both the surface reflectance and back surface reflectance are good in the visible light region of 400 to 800 nm. [Industrial applicability] 【0060】 High-precision and high-performance black dot plates for ophthalmic equipment can be manufactured using a simpler method. [Explanation of Symbols] 【0061】 10: Conventional black dot plate, 11: Substrate layer, 12: Black dot layer, 13: Anti-reflective layer, 20, 20a~20c: Black dot plate of the present invention, 21: Substrate layer, 22: Anti-reflective layer, 23: Black dot layer, 24: Light-shielding layer, 25: First refractive index matching layer, 25a: Dielectric layer, 25b: Metal thin layer, 26: Second refractive index matching layer, 26a: Dielectric layer, 26b: Metal thin layer, 30, 30a~30c: Black dot plate of the present invention, 31: Substrate layer, 32: Anti-reflective layer, 33: Black dot layer, 34: Light-shielding layer, 35: First refractive index matching layer, 35a: Dielectric layer, 35b: Metal thin layer, 36: Second refractive index matching layer, 36a: Dielectric layer, 36b: Metal thin layer, 40, 40a~40c: Black dot plate of the present invention, 41: Substrate layer, 42: Adhesive layer, 43: Black dot layer, 44: Light-shielding layer, 45: First refractive index matching layer, 45a: Dielectric layer, 45b: Metal thin layer, 46: Second refractive index matching layer, 46a: Dielectric layer, 46b: Metal thin layer, 47: Other substrate layer, 100: Ophthalmic equipment, 101: Illumination light source, 102: Lens, 103: Hole mirror, 103a: Hole, 104: Objective lens, 104a: Objective lens surface, 105: Lens, 106: Sensor, 200: Eye under examination, A-C: Optical path.

Claims

[Claim 1] The substrate layer, An anti-reflective layer consisting of at least one layer provided on the substrate layer, A black dot plate for an ophthalmic device, having a light-shielding layer provided as small black dots on the anti-reflective layer, Between the anti-reflective layer and the light-shielding layer, a first refractive index matching layer is provided, which consists of a dielectric layer that prevents reflection of incident light in the visible light region of 400 to 800 nm from the anti-reflective layer. A thin metal layer that absorbs the incident light is formed in the first refractive index matching layer. A second refractive index matching layer, which consists of a dielectric layer that prevents the reflection of the incident light from the air, is provided on the light-shielding layer. A black dot plate for ophthalmic equipment, characterized in that a thin metal layer that absorbs the incident light is formed in the second refractive index matching layer. [Claim 2] The substrate layer, A light-shielding layer provided as small black dots on the substrate layer, A black dot plate for an ophthalmic device, having an anti-reflective layer consisting of at least one layer provided on the substrate layer, covering the light-shielding layer, Between the substrate layer and the light-shielding layer, a first refractive index matching layer is provided, which consists of a dielectric layer that prevents reflection of incident light in the visible light region of 400 to 800 nm from the substrate layer. A thin metal layer that absorbs the incident light is formed in the first refractive index matching layer. Between the light-shielding layer and the anti-reflection layer, a second refractive index matching layer is provided, which consists of a dielectric layer that prevents reflection of the incident light from the anti-reflection layer. A black dot plate for ophthalmic equipment, characterized in that a thin metal layer that absorbs the incident light is formed in the second refractive index matching layer. [Claim 3] The substrate layer, A light-shielding layer provided as small black dots on the substrate layer, An adhesive layer provided on the substrate layer, covering the light-shielding layer, A black dot plate for an ophthalmic device, comprising the adhesive layer and another substrate layer provided on the adhesive layer, Between the substrate layer and the light-shielding layer, a first refractive index matching layer is provided, which consists of a dielectric layer that prevents reflection of incident light in the visible light region of 400 to 800 nm from the substrate layer. A thin metal layer that absorbs the incident light is formed in the first refractive index matching layer. A second refractive index matching layer, which consists of a dielectric layer that prevents the reflection of the incident light from the adhesive layer, is provided between the light-shielding layer and the adhesive layer. A black dot plate for ophthalmic equipment, characterized in that a thin metal layer that absorbs the incident light is formed in the second refractive index matching layer. [Claim 4] The black dot plate for ophthalmic devices according to any one of claims 1 to 3, characterized in that a thin metal layer made of the same material as the light-shielding layer is provided in the first refractive index matching layer and in the second refractive index matching layer. [Claim 5] The black dot plate for ophthalmic devices according to claim 4, wherein the metal thin layer is thinner than the dielectric layer provided on the substrate layer side of the metal thin layer and the dielectric layer provided on the air side of the metal thin layer. [Claim 6] The black dot plate for an ophthalmic device according to claim 4, wherein multiple layers of the metal thin layer are provided in the first refractive index matching layer and in the second refractive index matching layer. [Claim 7] The black dot plate for ophthalmic equipment according to claim 4, wherein the material of the light-shielding layer is Ni, Ti, Fe, Si, Ta, Nb, Zr, Mo, or W. [Claim 8] The black dot plate for an ophthalmic device according to claim 4, wherein the dielectric layer provided on the substrate layer side of the metal thin layer of the first refractive index matching layer, the dielectric layer provided on the air side of the metal thin layer of the first refractive index matching layer, and the dielectric layer provided on the substrate layer side of the metal thin layer of the second refractive index matching layer are oxides of the light shielding layer and the metal thin layer, and are different from the oxide of the dielectric layer provided on the air side of the metal thin layer of the second refractive index matching layer. [Claim 9] Light source and A hole mirror that reflects the light from the aforementioned illumination light source toward the eye under examination, The aforementioned aperture mirror is used to focus the reflected light toward the eye under examination, and The device comprises a black dot plate for ophthalmic equipment according to any one of claims 1 to 3, An ophthalmic device in which the light-shielding layer of the black spot plate for ophthalmic equipment is positioned to pass through the optical axis of the objective lens. [Claim 10] An illumination system that projects illumination light from an illumination source onto the eye to be examined via a hole mirror to illuminate the eye to be examined, The system comprises a photographic system having a photographic aperture provided in the optical path for photographing the eye under examination, The illumination system and the imaging system each have a mutually shared objective lens disposed between the eye to be examined and the aperture mirror, the illumination system has a black dot plate for ophthalmic devices as described in any of claims 1 to 4, and when the lens surface of the objective lens is considered as a reflective surface, the position where the image of the aperture of the imaging diaphragm is formed and the light-shielding layer are provided conjugately via the reflective surface, such that the image of the aperture of the imaging diaphragm is covered by the light-shielding layer.

Images