JP7198135B2 - optotype presentation device - Google Patents

Description

The present invention relates to a target presenting device that presents a target to an eye to be examined.

2. Description of the Related Art Ophthalmology clinics and optician shops are equipped with optotype presenting devices (also referred to as subjective optometry devices) that present various optotypes to an eye to be examined in order to subjectively test various visual functions of the eye to be examined. In such an optotype presenting apparatus, the optotype chart on the chart board is illuminated from behind with white light emitted from the light source, so that the optotype is separated from the subject's eye by a predetermined examination distance (approximately 5 m). Projection-type devices are known that project onto a screen placed on a wall.

A red-green test (also referred to as a red-green test) for finely adjusting the refractive power of a spectacle lens is known as one of the subjective tests of the visual function of an eye to be examined. In this red-green test, the subject's eye is presented with a red-green test target whose background is divided into green and red.

When a red-green test is performed with a projection type optotype presenting device, a dichroic filter including a red filter and a green filter and an optotype chart on which characters, symbols, etc. are formed are placed under white light emitted from a light source. project the red-green test target onto the screen by placing them in the respective optical paths. Thereby, the red-green test target is presented to the subject's eye.

A red glass filter that transmits red light in the red wavelength region is used as the red filter, and a green glass filter that transmits green light in the green wavelength region is used as the green filter. Note that the colored glass filter creates a specific color by absorbing part of the light in the wavelength range that is transmitted and most of the light in the wavelength range that is not transmitted. Therefore, the thickness of the colored glass filter changes the transmittance of light, thereby changing the brightness of the optotype. In addition, since the color glass filter has a relatively large variation in transmittance from member to member, it is necessary to control the thickness of each member in order to obtain the same brightness (performance).

2. Description of the Related Art In recent years, a projection type optotype presenting apparatus often uses a light emitting diode (LED) that emits white light as a light source. At this time, if the red glass filter and the green glass filter used with the conventional halogen lamp are directly illuminated with the white light of the LED, the red background of the red-green test target becomes darker than the green background.

Therefore, in the optotype presenting device described in Patent Literature 1, colored glass filters having different changes in visual characteristics with respect to changes in thickness are used as the red glass filter and the green glass filter. In the optotype presenting device described in Patent Document 1, the thicknesses of the two-color glass filters are adjusted to be the same in order to suppress the generation of shadows at the joined portions of the two-color glass filters, and the red-green test optotypes are used. The thickness of the two-color glass filter is determined so that the visual characteristics of the red background and the green background are substantially the same when presented to the subject's eye. As a result, the red background and the green background of the red-green test target can be presented to the subject's eye with approximately the same brightness.

JP 2008-188058 A

FIG. 11 is an explanatory diagram for explaining a problem of the optotype presenting device described in Patent Document 1. FIG. FIG. 12 is a schematic diagram of a red-green test target 14 presented to the subject's eye by the target presentation device described in Patent Document 1. As shown in FIG.

As shown in FIG. 11, the optotype presenting apparatus of Patent Document 1 uses an LED (not shown) to align a prescribed optotype chart 102 of a chart plate 100 and a prescribed mask opening 106 of a mask plate 104 during a red-green test. is placed in the optical path of the white light L1 emitted from the . A green glass filter 108 and a red glass filter 109 are provided in this mask opening 106 . Note that the green glass filter 108 and the red glass filter 109 may be provided on the optotype chart 102 .

The green glass filter 108 transmits the green light LG in the green wavelength range of the white light L1. Also, the red glass filter 109 transmits red light LR in the red wavelength region of the white light L1. Then, the target luminous flux L2 composed of the green light LG and the red light LR transmitted through the target chart 102 is imaged on a screen (not shown), and as shown in FIG. , a black object 16B, a green background 16G, and a red background 16R.

At this time, the green glass filter 108 and the red glass filter 109 have thickness. Therefore, even if the thicknesses of the green glass filter 108 and the red glass filter 109 are the same, as indicated by the arrow A in FIG. Part of the light L1 is transmitted through one and then through the other. In this case, the mixture of the green light LG and the red light LR produces a shadow 114 on the boundary between the green background 16G and the red background 16R of the red-green test target 14, as shown in FIG.

The shadow 114 described above also occurs when there is a chip in the joint portion (hereinafter abbreviated as joint portion) of the green glass filter 108 and the red glass filter 109 . Even if the joining portion is chamfered to prevent this chipping, a shadow 114 is generated by the chamfered surface. For this reason, there is a method of forming a black line at the joint so that the shadow 114 cannot be seen by the examinee, or polishing after the joint.

However, in the former method, the distance between the green target and the red target of the red-green test target 14 is increased, making it difficult for the examinee to compare the two targets. Further, the latter method requires polishing after bonding the green glass filter 108 and the red glass filter 109 together, which is very time-consuming.

Furthermore, the green glass filter 108 and the red glass filter 109 should be selected from mass-produced commercial products. For this reason, there is also the problem that the optimum colored glass filter corresponding to the type of light source cannot always be selected.

As described above, since the optotype presenting apparatus described in Patent Document 1 uses the green glass filter 108 and the red glass filter 109, it is still possible to present a good red-green test optotype 14 to the subject's eye. Have difficulty.

Further, if the thick green glass filter 108 and red glass filter 109 are provided on the mask plate 104 (the chart plate 100 may also be used), the weight of the mask plate 104 increases and the balance is lost, making high-speed rotation and stopping difficult. . As a result, it takes time to switch the target.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optotype presenting apparatus capable of presenting a favorable optotype to an eye to be examined.

An optotype presenting device for achieving the object of the present invention comprises a light source for emitting white light, an optotype chart arranged in the optical path of the white light, and a dichroic filter arranged in the optical path, wherein the green wavelength a dichroic filter having a green dichroic filter transmitting green light in the red wavelength range and a red dichroic filter transmitting red light in the red wavelength range.

According to this optotype presenting apparatus, it is possible to prevent the occurrence of shadows on the optotype (target image) presented to the eye to be inspected, and to significantly reduce the weight of the dichroic filter.

In the optotype presenting device according to another aspect of the present invention, the dichroic filter includes a translucent substrate, and a green dichroic filter and a red dichroic filter formed on the surface of the substrate. By this. It is possible to prevent the occurrence of a shadow on the target presented to the eye to be inspected.

In the optotype presenting device according to another aspect of the present invention, the substrate includes a green glass filter that transmits green light and a red glass filter that transmits red light, and the green dichroic filter is formed on the surface of the green glass filter. and a red dichroic filter is formed on the surface of the red glass filter. This makes it possible to deal with various light sources.

In the optotype presenting device according to another aspect of the present invention, the green dichroic filter and the red dichroic filter are joined on the surface of the substrate. By this. It is possible to prevent the occurrence of a shadow on the target presented to the eye to be inspected.

In the optotype presenting device according to another aspect of the present invention, the chart plate rotates about a first rotation axis parallel to the optical path, and a plurality of types of visual stimuli are displayed along the direction around the first rotation axis. a chart board on which a target chart is provided; and a first rotating mechanism for rotating the chart board about a first rotation axis to selectively arrange a plurality of types of target charts in an optical path; A filter is provided at a position corresponding to at least one optotype chart on the chart board. As a result, the weight of the dichroic filter can be reduced, and the number of parts of the optotype presenting device can be reduced.

In the optotype presenting device according to another aspect of the present invention, the chart plate rotates about a first rotation axis parallel to the optical path, and a plurality of types of visual stimuli are displayed along the direction around the first rotation axis. a chart plate on which target charts are provided; a first rotating mechanism for rotating the chart plate about a first rotation axis to selectively arrange a plurality of types of target charts in the optical path; a mask plate that rotates about a second rotation axis, the mask plate having a plurality of types of mask openings along the direction around the second rotation axis; and a mask plate about the second rotation axis. and a second rotating mechanism for selectively arranging a plurality of types of mask apertures in the optical path by rotating the dichroic filter at a position corresponding to at least one optotype chart on the chart plate or on the mask plate. It is provided at a position corresponding to at least one mask opening. As a result, the weight of the dichroic filter can be reduced, and the number of parts of the optotype presenting device can be reduced.

In the optotype presenting device according to another aspect of the present invention, the light source is a light emitting diode.

The present invention can present a good target to the eye to be examined.

1 is a schematic diagram of an optotype presenting device that selectively presents a plurality of types of optotypes to an eye to be examined; FIG. FIG. 3 is a diagram showing a list of 30 types of optotypes presented to an eye to be examined E by an optotype presenting device. It is a front view of a chart board. It is a front view of a mask board. FIG. 3 is an external perspective view of a dichroic filter corresponding to a red-green test target; 6 is an explanatory diagram for explaining transmission of green light and red light by the dichroic filter shown in FIG. 5; FIG. It is an explanatory view for explaining modification 1 of a dichroic filter. It is an explanatory view for explaining modification 2 of a dichroic filter. FIG. 11 is an explanatory diagram for explaining Modification 2 of the dichroic filter corresponding to the Worth 4-light test optotype; FIG. 11 is an explanatory diagram for explaining Modification 3 of the dichroic filter; FIG. 10 is an explanatory diagram for explaining a problem of the optotype presenting device described in Patent Literature 1; 1 is a schematic diagram of a red-green test optotype presented to an eye to be inspected by the optotype presenting device described in Patent Document 1. FIG.

[Configuration of Target Presentation Device]
FIG. 1 is a schematic diagram of an optotype presenting device 10 that selectively presents a plurality of types of optotypes 12 to an eye E to be examined. As shown in FIG. 1, the optotype presenting device 10 is selected by the examiner from among a plurality of types (for example, 30 types in this embodiment) of the optotypes 12 in order to subjectively test various visual functions of the eye E to be examined. By projecting the target 12 on the screen 9, the target 12 is presented to the subject's eye E (subject).

FIG. 2 is a diagram showing a list of 30 types of optotypes 12 presented to the subject's eye E by the optotype presenting device 10. As shown in FIG. The 30 types of optotypes 12 include a black optotype 13 representing black characters or symbols on a white background, and a red-green test optotype 14 and a worthy test optotype 14 having a green and red background or the optotype itself. A four-light test target 15 is included. In this specification, the visual target 12 (black visual target 13, red-green test visual target 14, and Worth 4-light test visual target 15) refers to a visual target image projected on the screen 9, that is, presented to the eye E to be examined. It is a visual target image to be used.

Examples of the black optotype 13 include Landolt rings, symbols, characters, etc. for visual acuity testing, radiographic optotypes for astigmatism testing, point group optotypes for cross-cylinder testing, and anisotropic vision testing. An anisotropy target, a cruciform oblique target for the cruciform oblique test, and a light source target for the Maddox test can be mentioned.

The red-green test optotype 14 is used in the known red-green test, and as shown in FIG. and including. The Worth 4-light test object 15 is used for the known Worth 4-light test and includes a black background 18B, a green object 18G and a red object 18R. The Worth 4-light test (Worth 4-light test index 15) is broadly included in the red-green test (red-green test index 14).

Returning to FIG. 1, the optotype presenting apparatus 10 includes a light source 20, a collimator lens 22, a chart plate 24, a first rotating mechanism 26, a mask plate 28, a second rotating mechanism 30, and a projection lens 32. , a control unit 34 and an operation unit 36 .

The light source 20 is a semiconductor light source that emits white light L1, more specifically an LED (light emitting diode). The symbol OA in the drawing indicates the optical path of the white light L1 (the optical axis of the optical system of the optotype presenting device 10). Also, as the light source 20 that emits the white light L1, a semiconductor light source other than an LED such as a laser diode may be used, or a halogen lamp may be used.

The collimator lens 22 converts the white light L1 emitted from the light source 20 into a parallel light flux (substantially parallel light flux), and then emits the white light L1 toward the mask plate 28 . As a result, the white light L1 passes through the mask opening 29 of the mask plate 28 and the optotype chart 25 of the chart plate 24 in order. Note that the positional relationship between the chart plate 24 and the mask plate 28 may be reversed.

FIG. 3 is a front view of the chart board 24. FIG. As shown in FIG. 3 and FIG. 1 already described, the chart plate 24 is a disk-shaped glass plate that rotates around a first rotation axis 38 parallel to the optical path OA. On this chart board 24, along the direction around the first rotation axis 38 (that is, along the same circle centered on the first rotation axis 38), there are 30 types of targets 12 corresponding to the above-mentioned 30 types of targets 12. Thirty types of optotype charts 25 are formed by chromium vapor deposition.

In FIG. 3, in order to prevent complication of the drawing, the optotype charts 25 corresponding to the 30 types of optotypes 12 are simply represented by numbers "1" to "30". For example, the red-green test object 14 is represented by the number "8".

The optotype chart 25 corresponding to each black optotype 13 is obtained by forming a pattern corresponding to each black optotype 13 on a chart plate 24 by chromium vapor deposition. The optotype chart 25 corresponding to the red-green test optotype 14 is obtained by forming a pattern corresponding to the black optotype 16B on the chart plate 24 by chromium vapor deposition. Further, the optotype chart 25 corresponding to the Worth 4-light test optotype 15 is obtained by forming a pattern corresponding to the black background 18B on the chart plate 24 by chromium vapor deposition.

The first rotation axis 38 is provided at a position vertically shifted from the optical path OA so that one of the optotype charts 25 on the chart plate 24 is arranged in the optical path OA. Accordingly, by rotating the chart plate 24 around the first rotation axis 38, one of the 30 types of optotype charts 25 is selectively arranged on the optical path OA.

The first rotating mechanism 26 is composed of a motor (not shown) and a drive transmission mechanism (not shown) that transmits the rotational driving force of this motor to the first rotating shaft 38. , rotates the first rotating shaft 38 . As a result, the chart plate 24 rotates around the first rotation shaft 38 .

FIG. 4 is a front view of the mask plate 28. FIG. As shown in FIG. 4 and FIG. 1 already described, the mask plate 28 is a disk-shaped glass plate that rotates around a second rotation axis 40 parallel to the optical path OA. A light shielding layer 28a (see FIG. 6) is formed on one surface (or both surfaces) of the mask plate 28 by vapor deposition of chromium. In the light shielding layer 28a of the mask plate 28, along the direction around the second rotation axis 40 (that is, along the same circle centered on the second rotation axis 40), a plurality of light shielding layers capable of transmitting the white light L1 are provided. A type of mask opening 29 is formed. The mask plate 28 may be made of a material that does not transmit the white light L1, such as metal.

The plurality of types of mask apertures 29 include, for example, an aperture having a shape that allows the white light L1 to be applied only to a partial region of the optotype chart 25 corresponding to the black optotype 13 for visual acuity testing, and an aperture that allows the entire optotype chart 25 to be illuminated. The region includes openings of various shapes, such as an opening having a shape that can irradiate the white light L1. Thereby, the target chart 25 can be irradiated with the white light L<b>1 within the irradiation range corresponding to the mask opening 29 .

Also, at positions corresponding to the mask openings 29 in part of the mask plate 28, dichroic filters 44 respectively corresponding to the red-green test target 14 and the Worth 4-light test target 15 are provided by a method such as pasting. ing. A dichroic filter 44 corresponding to the red-green test target 14 colors the background of the red-green test target 14 into a green background 16G and a red background 16R. Also, the dichroic filter 44 corresponding to the Worth 4-light test target 15 color-codes the target itself into a green target 18G and a red target 18R.

The second rotating shaft 40 is provided at a position shifted in the above-described vertical direction from the optical path OA so that one of the mask apertures 29 (dichroic filters 44) of the mask plate 28 is arranged in the optical path OA. ing. Accordingly, by rotating the mask plate 28 about the second rotation axis 40, one of the mask apertures 29 (dichroic filters 44) is selectively arranged in the optical path OA.

The second rotating mechanism 30 has the same configuration as the first rotating mechanism 26 described above, and rotates the second rotating shaft 40 under the control of the controller 34, which will be described later. As a result, the mask plate 28 rotates about the second rotating shaft 40 .

Returning to FIG. 1, the control unit 34 rotates each unit (the light source 20, the first rotation mechanism 26, and the second rotation mechanism 30) of the optotype presenting device 10 according to various input operations on the operation unit 36 by the examiner. control the drive of This input operation includes, for example, an on/off operation of the light source 20, a selection operation of the optotype 12, a mask selection operation, and the like.

The control unit 34 turns the light source 20 on and off according to the on/off operation of the light source 20 input to the operation unit 36 .

The control unit 34 drives the first rotating mechanism 26 to rotate the first rotating shaft 38 and the chart plate 24 according to the selection operation of the optotype 12 input to the operation unit 36, thereby responding to the selection operation. The optotype chart 25 is placed on the optical path OA.

Further, when the selection operation input to the operation unit 36 is the selection operation of the black optotype 13, the control unit 34 drives the second rotation mechanism 30 to rotate the second rotation shaft 40 and the mask plate 28. By doing so, the mask aperture 29 capable of irradiating the white light L1 to the entire region of the optotype chart 25 is arranged in the optical path OA. As a result, the white light L1 emitted from the collimator lens 22 passes through the mask opening 29 and the optotype chart 25 in order, and the optotype light flux L2 of the black optotype 13 is emitted from the optotype chart 25. FIG.

On the other hand, when the selection operation input to the operation unit 36 is the selection operation of the red-green test optotype 14 or the Worth 4-light test optotype 15, the control unit 34 drives the second rotating mechanism 30 to rotate the By rotating the two-rotation shaft 40 and the mask plate 28, the dichroic filter 44 corresponding to the selection operation is arranged in the optical path OA. As a result, the white light L1 emitted from the collimator lens 22 passes through the dichroic filter 44 and the optotype chart 25 in order, and the red/green test optotype 14 or the Worth 4-light test optotype 15 is emitted from the optotype chart 25. A target light beam L2 is emitted.

The control unit 34 drives the second rotating mechanism 30 to rotate the second rotating shaft 40 and the mask plate 28 according to the mask operation input to the operation unit 36, thereby opening the mask opening corresponding to the mask selection operation. 29 is placed in the optical path OA. As a result, the irradiation range of the white light L1 irradiated onto the optotype chart 25 is limited by the mask opening 29, so that, for example, the black optotypes 13 for visual acuity testing arranged in a matrix form one vertical line, one horizontal line, and one horizontal line. Alternatively, only one can be selectively presented to the eye E to be examined.

The projection lens 32 forms an image of the optotype luminous flux L2 of the optotype 12 transmitted through the optotype chart 25 on the screen 9 provided at a position separated from the subject's eye E by a predetermined examination distance D (for example, 5 m). Let Thereby, the visual target 12 is presented to the eye E to be examined.

[Dichroic filter]
FIG. 5 is an external perspective view of a dichroic filter 44 corresponding to the red-green test target 14. FIG. As shown in FIG. 5 , the dichroic filter 44 includes a glass substrate 46 , a green dichroic filter (hereinafter referred to as GDF) 48 and a red dichroic filter (hereinafter referred to as RDF) 49 . In FIG. 5 (similarly to the other drawings), in order to clarify each part of the dichroic filter 44, the thickness ratio of each part is disregarded and the thicknesses of the GDF 48 and RDF 49 are partially exaggerated. Dichroic filters in this specification also include dichroic mirrors.

The glass substrate 46 corresponds to the translucent substrate of the present invention, and is a transparent substrate that transmits the white light L1.

The GDF 48 and RDF 49 are dielectric multilayer films having different refractive indices, and are formed on the surface of the glass substrate 46 by a known film formation method such as vapor deposition or sputtering. Thereby, the GDF 48 and the RDF 49 can be sequentially formed on the surface of the glass substrate 46 so as to be in contact with each other, and the GDF 48 and the RDF 49 can be bonded on this surface. Alternatively, GDF 48 and RDF 49 can be formed for each defined area on this surface. Furthermore, by using a known film forming method, a large number of pairs of GDF 48 and RDF 49 can be formed in a matrix on one glass plate (work). Accordingly, by dividing the glass substrate into each pair of GDF 48 and RDF 49 after this formation, the dichroic filters 44 can be mass-produced.

Since the GDF 48 and RDF 49 are thin films, they are supported by the glass substrate 46 . The thickness of the glass substrate 46 is not particularly limited as long as the glass substrate 46 can support the GDF 48 and the RDF 49, and can be formed thin.

FIG. 6 is an explanatory diagram for explaining transmission of the green light LG and the red light LR by the dichroic filter 44 shown in FIG. In FIG. 5, the GDF 48 and RDF 49 side surfaces of the dichroic filter 44 are attached to the mask plate 28 (mask opening 29), but the glass substrate 46 side surface is attached to the mask plate 28. may be

In FIG. 6, the dichroic filter 44 is provided on one side of the mask plate 28 facing the collimator lens 22, but the side opposite to the one side of the mask plate 28 (the side facing the chart plate 24) side). That is, if the dichroic filter 44 is positioned corresponding to the mask opening 29 of the mask plate 28 (position on the optical path of the white light L1 passing through the mask opening 29), the dichroic filter 44 can may be provided in any of the

As shown in FIG. 6, when the dichroic filter 44 is arranged in the optical path OA, the white light L1 emitted from the collimator lens 22 passes through the glass substrate 46 and enters the GDF 48 and the RDF 49, respectively.

The GDF 48 transmits only the green light LG in the green wavelength range among the white light L1, and reflects the surplus light in other wavelength ranges toward the collimator lens 22 side. Further, the RDF 49 transmits only the red light LR in the red wavelength range among the white light L1, and reflects the surplus light in other wavelength ranges toward the collimator lens 22 side. As a result, one of the right and left halves of the optotype chart 25 corresponding to the red-green test optotype 14 is illuminated with the green light LG and the other is illuminated with the red light LR, so that the green background 16G and the red background are illuminated. The target luminous flux L2 of the red-green test target 14 color-coded with the background 16R is projected onto the screen 9. FIG.

Note that the filter characteristics of the GDF 48 and RDF 49 are determined as follows, for example, when the light source 20 is a standard light source (A light source). However, the present invention is not limited to this. The peak of the transmission characteristic of the GDF 48 is within the wavelength range of 530 nm to 550 nm, and the peak of the transmission characteristic of the RDF 49 is within the wavelength range of 600 nm to 620 nm. The full width at half maximum of the spectral luminous transmittance of GDF48 and RDF49 is 60 nm. Furthermore, the spectral luminous transmittances of the GDF 48 and RDF 49 are adjusted so that the lower spectral luminous transmittance does not fall below the higher spectral luminous transmittance of 15%.

Furthermore, the GDF 48 has a spectral transmittance of 0.02 or less at a wavelength of 595 to 605 nm and a spectral transmittance of 0.01 or less at a wavelength of 605 to 700 nm. Further, the RDF 49 has a spectral transmittance of 0.02 or less at a wavelength of 595 to 605 nm and a spectral transmittance of 0.01 or less at a wavelength of 400 to 595 nm.

The dichroic filter 44 corresponding to the Worth 4-light test optotype 15 is the same as the dichroic filter 44 corresponding to the red-green test optotype 14 described above, except that the patterns (shapes) of the GDF 48 and RDF 49 are different. Since they have basically the same configuration, a detailed description will be omitted.

As described above, in the present embodiment, by using the thin film (thin layer) GDF 48 and RDF 49 as the green and red filters of the dichroic filter 44, the thickness of the green and red filters is greater than when the green and red filters are formed of colored glass filters. can be significantly thinned. Therefore, even if the white light L1 is obliquely incident on the dichroic filter 44 as shown in FIG. As a result, as shown in FIG. 12 described above, the shadow 114 is prevented from being generated at the boundary between the green background 16G and the red background 16R in the red-green test target 14. red-green test target 14 can be presented.

In addition, since the GDF 48 and the RDF 49 can be formed in a state of being bonded to each other on the glass substrate 46 using a known film forming method, the bonding portion of the GDF 48 and the RDF 49 is prevented from being chipped. This prevents the shadow 114 from appearing on the boundary between the green background 16G and the red background 16R. Moreover, it is not necessary to provide a gap between the green background 16G and the red background 16R, or to grind them after the above-described bonding, unlike the conventional art using a colored glass filter. As a result, the good red-green test target 14 and the Worth 4-light test target 15 can be presented to the eye E to be examined, and the labor for polishing can be reduced.

Furthermore, the GDF 48 and RDF 49 have a high degree of freedom in designing transmission performance, unlike commercially available colored glass filters, so that the performance of the GDF 48 and RDF 49 can be optimized according to the type of light source 20 . As a result, the red-green test optotype 14 and the Worth 4-light test optotype 15 can be presented to the eye E to be examined.

Furthermore, since the GDF 48 and RDF 49 are thin films, the weight of the dichroic filter 44 can be significantly reduced as compared with the case of using color glass filters. As a result, the weight increase of the mask plate 104 can be minimized, so that the mask plate 28 can be rotated and stopped at high speed, and the target 12 can be switched in a short time.

[Modification]
A modified example of the dichroic filter 44 (the optotype presenting device 10) will be described below. Since the modified example has basically the same configuration as the above embodiment except for a part, the same reference numerals are given to the same functions or configurations as the above embodiment, and the explanation thereof is omitted. .

<Modification 1>
FIG. 7 is an explanatory diagram for explaining Modification 1 of the dichroic filter 44. As shown in FIG. In the above embodiment, the dichroic filter 44 is provided on the mask plate 28, but as shown in FIG. It may be installed in a position where Also in this case, the same effect as the above embodiment can be obtained. The present invention can also be applied to a type of optotype presenting apparatus 10 without the mask plate 28 .

Although the surface of the dichroic filter 44 on the GDF 48 and RDF 49 side is attached to the chart plate 24 (optical target chart 25), conversely, even if the surface on the glass substrate 46 side is attached to the chart plate 24, good.

In FIG. 7, the dichroic filter 44 is provided on one side of the chart plate 24 facing the mask plate 28. However, the dichroic filter 44 is provided on the side opposite to the one side of the chart plate 24 (the side facing the projection lens 32). side). That is, if the dichroic filter 44 is at a position corresponding to the optotype chart 25 on the chart plate 24 (position on the optical path of the white light L1 passing through the optotype chart 25), the dichroic filter 44 can It may be provided on either side.

<Modification 2>
FIG. 8 is an explanatory diagram for explaining Modification 2 of the dichroic filter 44 corresponding to the red-green test target 14. As shown in FIG. FIG. 9 is an explanatory diagram for explaining Modified Example 2 of the dichroic filter 44 corresponding to the Worth 4-light test target 15. In FIG.

In the above embodiment, the GDF 48 and RDF 49 are formed on the glass substrate 46, but as shown in FIGS. may be formed at positions corresponding to the optotype charts 25 (on either side of the chart plate 24). Alternatively, although not shown, the GDF 48 and the RDF 49 may be formed at positions corresponding to the mask openings 29 of the mask plate 28 (glass plate) (both sides of the mask plate 28 are acceptable). In this case, part of the chart plate 24 or part of the mask plate 28 functions as the translucent substrate of the present invention.

Thus, even when the GDF 48 and RDF 49 are directly formed on the chart plate 24 or the mask plate 28, the same effects as those of the above embodiment can be obtained. Further, in this case, the glass substrate 46 is not required, so the weight of the dichroic filter 44 can be reduced. Furthermore, the number of parts can be reduced, and the step of bonding the separately formed dichroic filter 44 to the chart plate 24 or the mask plate 28 can be omitted.

<Modification 3>
FIG. 10 is an explanatory diagram for explaining Modification 3 of the dichroic filter 44. As shown in FIG. In the dichroic filter 44 of the above embodiment, the GDF 48 and RDF 49 are formed on the transparent glass substrate 46, but the GDF 48 and RDF 49 may be formed on a colored glass filter.

Specifically, as shown in FIG. 10, the dichroic filter 44 is composed of a GDF 48 and an RDF 49, and a green glass filter 50 and a red glass filter 51 corresponding to the transparent substrate of the present invention. Incidentally, the dichroic filter 44 may be provided on either surface of the mask plate 28 , and may be provided on either surface of the chart plate 24 .

The green glass filter 50, like the GDF 48, transmits green light LG in the green wavelength range. Also, the red glass filter 51 transmits red light LR in the red wavelength range, like the RDF 49 . These green glass filter 50 and red glass filter 51 are bonded by a known method.

The GDF 48 of Modification 3 is formed on the surface of the green glass filter 50 by a known film formation method, and the RDF 49 of Modification 3 is formed on the surface of the red glass filter 51 by a known film formation method. be. The film formation of the GDF 48 and the RDF 49 may be performed either before or after bonding the green glass filter 50 and the red glass filter 51 .

By using a so-called hybrid filter in which a glass filter and a dichroic filter are combined as green and red color filters in this way, it is possible to support a wider variety of light sources 20 . In addition, by combining the glass filter and the dichroic filter, the thickness of the color filter can be made thinner than when the color filter is constituted by the glass filter alone. As a result, as in the above embodiment, the shadow 114 is prevented from being generated at the boundary between the green background 16G and the red background 16R. A test target 15 can be presented.

[others]
In the above embodiments and modifications, the dichroic filter 44 corresponding to the red-green test target 14 and the Worth 4-light test target 15 is taken as an example, but the background or the target itself is color-coded into green and red. The present invention can also be applied to dichroic filters 44 corresponding to other known visual targets 12 .

In the above embodiments and modifications, the GDF 48 and RDF 49 are formed on the glass plate (glass substrate 46, chart plate 24, mask plate 28). GDF 48 and RDF 49 may be formed on a substrate made of other known materials.

The optotype presenting apparatus 10 of the above-described embodiment and modifications forms (projects) the optotype light flux L2 on the screen 9. For example, an optical system is used to form a virtual image of the optotype 12 based on the optotype light flux L2. is imaged at a position separated from the eye to be examined E by the examination distance D, the present invention can also be applied to a space-saving type optotype presentation device 10 that can be installed at a short distance from the eye to be examined E.

REFERENCE SIGNS LIST 10: optotype presenting device 12: optotype 14: red green test optotype 15: Worth 4-light test optotype 20: light source 24: chart plate 25: optotype chart 26: first rotating mechanism 28: mask plate 29: mask Opening 30 Second rotating mechanism 38 First rotating shaft 40 Second rotating shaft 44 Dichroic filter 46 Glass substrate 48 Green dichroic filter (GDF)
49 Red dichroic filter (RDF)
50... Green glass filter 51... Red glass filter

Claims (6)

a light source that emits white light;
an optotype chart positioned in the optical path of the white light;
a dichroic filter disposed in the optical path, the dichroic filter having a green dichroic filter that transmits green light in the green wavelength range and a red dichroic filter that transmits red light in the red wavelength range;
with
The dichroic filter is
a translucent substrate;
the green dichroic filter and the red dichroic filter formed on the surface of the substrate;
A target presentation device comprising: the substrate includes a green glass filter that transmits the green light and a red glass filter that transmits the red light;
2. The optotype presenting device according to claim 1 , wherein the green dichroic filter is formed on the surface of the green glass filter, and the red dichroic filter is formed on the surface of the red glass filter. 3. The optotype presenting device according to claim 1 , wherein the green dichroic filter and the red dichroic filter are joined on the surface of the substrate. a chart board that rotates about a first rotation axis parallel to the optical path, the chart board having a plurality of types of the optotype charts provided along a direction around the first rotation axis;
a first rotating mechanism that rotates the chart plate about the first rotation axis to selectively arrange a plurality of types of the optotype charts in the optical path;
with
4. The optotype presenting device according to any one of claims 1 to 3 , wherein the dichroic filter is provided on at least one position of the chart plate corresponding to the optotype chart. a chart board that rotates about a first rotation axis parallel to the optical path, the chart board having a plurality of types of the optotype charts provided along a direction around the first rotation axis;
a first rotating mechanism that rotates the chart plate about the first rotation axis to selectively arrange a plurality of types of the optotype charts in the optical path;
a mask plate that rotates about a second rotation axis parallel to the optical path, the mask plate having a plurality of types of mask openings along a direction around the second rotation axis;
a second rotating mechanism that rotates the mask plate about the second rotation axis to selectively arrange a plurality of types of mask apertures in the optical path;
with
4. The dichroic filter according to any one of claims 1 to 3 , wherein the dichroic filter is provided at a position corresponding to at least one of the optotype charts on the chart plate or at a position corresponding to at least one mask aperture on the mask plate. 2. The optotype presenting device according to item 1. 6. The optotype presenting device according to any one of claims 1 to 5 , wherein the light source is a light emitting diode.

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