Ophthalmic device and sheet member

Abstract

To prevent properly dust or the like from entering the inside of a housing of an ophthalmologic apparatus.SOLUTION: An ophthalmologic apparatus includes an optical system having an optical member for acquiring eye characteristics of a subject eye, and a housing 26 for storing the optical system. The housing 26 has a screw hole 26a, and a sheet member 28 arranged on one surface (inside surface 26c) inside the housing 26 so as to cover the screw hole 26a. The sheet member 28 is circular in a plane view, and an elongation with a machine screw 27 inserted into the screw hole 26a is below a limit elongation of the sheet member 28.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an ophthalmic device and a sheet member used in the ophthalmic device. [Background technology]

[0002] In order to prevent optical members inside the housing from becoming soiled with dust or the like and causing a decrease in optical performance, an ophthalmic device is known in which a cleaning window with a door is provided in the housing, and the inside of the housing can be cleaned through this cleaning window (see, for example, Patent Document 1). However, in the ophthalmic device of Patent Document 1, opening and closing the door may actually allow dust or the like to enter the inside of the housing through the cleaning window.

[0003] Incidentally, ophthalmic devices are assembled in clean rooms, which prevents dust and other particles from getting inside the housing during manufacturing. However, when screws are screwed into screw holes, metal pieces rub against each other, generating metal chips (cut chips) that can fall into the housing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-10679 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure has been made in light of the above-mentioned problem, and aims to appropriately prevent dust and the like from entering the housing of an ophthalmic apparatus. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the ophthalmic device of the present disclosure comprises an optical system having optical elements for acquiring the eye characteristics of the subject's eye, and a housing that houses the optical system, wherein the housing has screw holes and a sheet member arranged on one surface of the interior side of the housing so as to cover the screw holes. [Effects of the Invention]

[0007] With this configuration, it is possible to appropriately prevent dust and the like from entering the housing of the ophthalmic apparatus. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing the overall configuration of an ophthalmologic apparatus according to a first embodiment. [Figure 2] 3 is a perspective view showing the positional relationship between a screw hole in a housing, a screw threaded into the screw hole, and a sheet member of the first embodiment that is placed in the screw hole. FIG. [Figure 3] 1A is a cross-sectional view showing the state in which a sheet member is attached to the inner surface of the housing to cover the screw holes, and FIG. 1B is a cross-sectional view showing the state in which a screw is screwed into the screw hole and the sheet member is stretched. [Figure 4] FIG. 2(a) is a cross-sectional view of the sheet member of the first embodiment, and FIG. 2(b) is a cross-sectional view of the sheet member of a modified example. [Figure 5] 10A is a perspective view showing the positional relationship between the screw holes in the housing of the ophthalmic device of the second embodiment, the screws screwed into the screw holes, and the sheet member of the second embodiment placed in the screw holes, and FIG. 10B is a cross-sectional view of the sheet member of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an ophthalmic apparatus and a sheet member according to an embodiment of the present disclosure will be described with reference to the drawings.

[0010] (First embodiment) Hereinafter, the configuration of an ophthalmic apparatus 1 according to a first embodiment of the present disclosure and a sheet member 28 used in the ophthalmic apparatus 1 will be described with reference to FIGS.

[0011] The ophthalmic apparatus 1 of the first embodiment is an open-eye type ophthalmic apparatus that can measure the eye characteristics of both eyes simultaneously while the subject has both eyes open. Note that the ophthalmic apparatus 1 of Example 1 can also measure the eye characteristics of each eye separately by blocking one eye or turning off the fixation target. In other words, the ophthalmic apparatus of the present disclosure is not limited to the open-eye type, and can also be applied to an ophthalmic apparatus that measures the eye characteristics of each eye separately.

[0012] The ophthalmologic apparatus 1 of the first embodiment includes a support base 10, a measurement unit 20, and an operation controller 30 (operation unit), as shown in Fig. 1. Throughout this specification, X, Y, and Z axes are defined as shown in Fig. 1, and the left-right direction as seen from the subject undergoing eye examination is defined as the X direction, the up-down direction (vertical direction) as the Y direction, and the direction perpendicular to the X and Y directions (depth direction of the measurement unit 20) as the Z direction.

[0013] The support base 10 has a support column 11 standing upright from the floor surface and an optometry table 12 supported by the support column 11. The optometry table 12 is a platform on which devices and tools used in optometry, such as the operation controller 30, are placed and which supports the posture of the subject. The optometry table 12 may be supported by the support column 11 so that its position in the Y direction (height position) is adjustable.

[0014] The measurement unit 20 has an arm 21, a measurement head 22, a forehead support 23, and a measurement side control unit 24. One end of the arm 21 is supported by the tip of the support column 11, and the other end extends from the support column 11 toward the front side (the subject side) along the Z direction, with the measurement head 22 attached to the tip. As a result, the measurement head 22 is suspended from the support column 11 via the arm 21 above the optometry table 12. The arm 21 is movable in the Y direction relative to the support column 11. The arm 21 may also be movable in the X direction or the Z direction relative to the support column 11.

[0015] The measurement head 22 has a drive unit 22a and a pair of right and left measurement units 22R and 22L provided below the drive unit 22a, and measures the ocular characteristics of the subject's eye. The right measurement unit 22R and the left measurement unit 22L are paired to individually correspond to the subject's left and right eyes. The right measurement unit 22R incorporates a right measurement optical system (optical system) 25R that measures the ocular characteristics of the subject's right eye. The left measurement unit 22L incorporates a left measurement optical system (optical system) 25L that measures the ocular characteristics of the subject's left eye. The measurement results by the measurement head 22 are input to the measurement-side control unit 24.

[0016] The drive unit 22a is a mechanism that drives the right measurement unit 22R and the left measurement unit 22L individually to move horizontally (X direction), move vertically (Y direction), rotate in the X direction, and rotate in the Y direction.

[0017] The right measurement optical system 25R and the left measurement optical system 25L are configured with a plurality of optical members such as lenses, mirrors, visual targets, etc. The right measurement optical system 25R and the left measurement optical system 25L include an observation system for observing the anterior segment of the eye to be examined, a fixation target projection system for presenting a fixation target to the eye to be examined, an objective measurement system for irradiating measurement light onto the fundus of the eye to be examined and receiving reflected light of the measurement light reflected by the fundus of the eye to be examined, a subjective measurement system for presenting a subjective visual target to the eye to be examined, etc.

[0018] Here, the objective measurement system objectively measures the ocular characteristics of the subject's eye based on the results of receiving reflected light, and also performs photography to obtain an image of the subject's eye. That is, the objective measurement system performs objective refraction measurement (REF measurement), corneal shape measurement (KERATOMETRY), intraocular pressure measurement, fundus photography, tomography using optical coherence tomography (OCT photography), measurement using OCT, etc. Note that objective measurement is performed not only during objective measurement but also during subjective measurement.

[0019] In addition, the subjective measurement system subjectively measures the ocular characteristics of the subject's eye based on the subject's response to presented targets. That is, the subjective measurement system performs subjective refraction measurements such as distance tests, near tests, contrast tests, and glare tests, as well as visual field tests.

[0020] The forehead rest 23 is disposed between the right measurement part 22R and the left measurement part 22L and is provided in the measurement unit 20. The forehead rest 23 supports the subject's face by bringing part of the subject's face (forehead) into contact with it during measurement of eye characteristics. That is, the subject facing the ophthalmology table 12 presses his or her forehead against the forehead rest 23 to stabilize the face so that the orientation and position do not move.

[0021] The measurement-side control unit 24 is an information processing device provided below the optometry table 12, and controls each part of the measurement unit 20 in an integrated manner based on a control signal transmitted from the operation controller 30. The measurement-side control unit 24 also transmits the measurement results of the ocular characteristics of the subject's eye measured by the measurement head 22 to the operation controller 30. The measurement-side control unit 24 stores the measurement results of the measurement head 22 in the memory unit 24a. Here, the "measurement results" include the type of measurement (objective or subjective), the objective measurement values ​​(spherical power, cylindrical power, cylindrical axis), the type of presented optotype during subjective measurement, and the measurement conditions during subjective measurement (spherical power, cylindrical power, cylindrical axis). Based on a control signal from the operation controller 30, the measurement-side control unit 24 reads out the measurement results stored in the memory unit 24a and transmits them to the operation controller 30.

[0022] The operation controller 30 is an information processing device that accepts operations by the examiner and outputs a control signal to the measurement-side control unit 24 of the measurement unit 20. This operation controller 30 is, for example, a tablet terminal or a smartphone, and is separated from the measurement unit 20 so that it can be carried by the examiner. The operation controller 30 may be a notebook personal computer, a desktop personal computer, or a controller dedicated to the ophthalmologic apparatus 1. The operation controller 30 exchanges information with the measurement-side control unit 24 via wireless communication or network communication. That is, the operation controller 30 can communicate with the measurement unit 20 via the measurement-side control unit 24.

[0023] The operation controller 30 comprises a display unit 31 and an operation-side control unit 32. The display unit 31 is made up of a touch panel display provided on the surface of the operation controller 30. The display unit 31 is made up of a display surface 31a on which images and the like are displayed, and a plurality of touch panel-type input buttons (operation unit) 31b superimposed on the display surface 31a. The operation-side control unit 32 is made up of a microcomputer built into the operation controller 30. The operation-side control unit 32 displays images on the display surface 31a based on the measurement results and detection results transmitted from the measurement-side control unit 24, and outputs control signals to the measurement-side control unit 24 in response to operations on the input buttons 31b.

[0024] When the examiner taps a predetermined input button 31b on the operation controller 30, a predetermined control signal is transmitted from the operation-side control unit 32 to the measurement-side control unit 24. The measurement-side control unit 24 controls the measurement unit 20 based on the received control signal to perform measurement of eye characteristics by any objective measurement or subjective measurement, alignment, detection of the subject's support state, etc. Furthermore, once measurement of eye characteristics is performed by the measurement head 22, the measurement-side control unit 24 transmits the measurement results to the operation-side control unit 32 of the operation controller 30. The operation-side control unit 32 displays a predetermined screen on the display surface 31a based on the received measurement results.

[0025] The measurement unit 20, including the drive unit 22a, the right measurement unit 22R, and the left measurement unit 22L, is covered with a resin cover member 22b. The right measurement unit 22R and the left measurement unit 22L incorporate right and left measurement optical systems 25R and 25L, respectively. The right measurement optical system 25R and the left measurement optical system 25L are covered by left and right housings 26R and 26L (hereinafter, simply referred to as "housings 26" without distinction between left and right) made of metal or the like. As shown in FIG. 2, the housing 26 has multiple screw holes (internal threads) 26a. Metal screws (external threads) 27 are threaded into the screw holes 26a from one outer surface (outer surface 26b) of the housing 26 to connect the various parts of the housing 26 and assemble the measurement head 22, which houses the drive unit 22a, the right measurement optical system 25R, and the left measurement optical system 25L. The measurement head 22 is attached to the support 11 to fabricate the ophthalmic device 1.

[0026] The ophthalmic apparatus 1 is assembled in a clean room or the like to prevent dust, dirt, and the like from entering the inside of the cover member 22b and the inside of the housing 26. This prevents dirt and the like from entering the inside of the ophthalmic apparatus 1, and in particular prevents dirt and the like from adhering to the optical members of the right measurement optical system 25R and the left measurement optical system 25L inside the housing 26 (housings 26R and 26L) and affecting the measurement accuracy of eye characteristics.

[0027] However, when screwing the screw 27 into the screw hole 26a of the housing 26, metal pieces rub against each other, generating metal chips (chips), which may fall into the housing 26. If these metal chips adhere to the optical components of the right measurement optical system 25R and the left measurement optical system 25L, they may affect the accuracy of measuring the eye characteristics.

[0028] To solve such problems, the ophthalmologic apparatus 1 of the first embodiment has a sheet member 28 attached to one surface (inner surface 26c) on the inner side of the housing 26 to cover the screw holes 26a, as shown in Fig. 3(a). In the first embodiment, the screw holes 26a are opened in the housing 26 by burring, thereby providing burring portions 26d that protrude inward. The inside of this burring portion 26d forms the screw holes 26a. The sheet member 28 covers the screw holes 26a together with the burring portions 26d.

[0029] By arranging sheet member 28 in this manner, even if the tip of screw 27 threaded into screw hole 26a protrudes into housing 26 and presses against sheet member 28, sheet member 28 will stretch inward, as shown in Fig. 3(b), and will not break or be perforated. As a result, even when screw 27 is threaded, sheet member 28 will adequately seal screw hole 26a, preventing metal chips from entering housing 26 through screw hole 26a.

[0030] Although the sheet member 28 in the first embodiment has a circular shape in a plan view, the present invention is not limited to this and may have an elliptical shape in a plan view, or any other shape such as a triangle, a rectangle, or any other polygon (more preferably a regular polygon) in a plan view. By making the sheet member 28 circular in a plan view, the pressing force from the screws 27 can be uniformly distributed, thereby appropriately preventing breakage or peeling.

[0031] Furthermore, the screw holes 26a in which the sheet member 28 is placed are not limited to the screw holes 26a of the housing 26 covering the right measurement optical system 25R and the left measurement unit 22L, and by placing the sheet member 28 also in screw holes of the housing covering the drive unit 22a and the measurement side control unit 24, etc., it is possible to appropriately prevent the intrusion of dust, metal chips, etc. into the interior of the ophthalmic device 1.

[0032] As shown in Figure 4(a), this sheet member 28 has a sheet body 28a and an adhesive portion 28b provided on one surface of this sheet body 28a. The sheet member 28 has a predetermined elongation rate. This elongation rate essentially indicates the elongation rate of the sheet body 28a. In other words, it is assumed here that the adhesive portion 28b does not affect the elongation rate of the sheet member 28. "Having an elongation rate" means that an object has the property of stretching when pulled.

[0033] The sheet body 28a is formed by using a single stretchable resin film such as PET (polyethylene terephthalate) or polyurethane, or by laminating multiple types of resin films. The sheet body 28a preferably has a critical elongation of 370% or more, and more preferably 400% or more, as measured by a method conforming to JIS K7311, but is not limited to these values. The "critical elongation" refers to the maximum elongation (%) that an object can withstand when pulled without breaking.

[0034] However, the limit elongation of the sheet body 28a is not limited to the above value. As will be described later, it is sufficient that the limit elongation of the sheet body 28a itself is greater than the elongation of the sheet body 28a when the sheet body 28a is pressed and stretched by the tip of the screw 27 protruding from the inner surface 26c of the housing 26. In other words, it is desirable to determine the size and elongation of the sheet body 28a so that the sheet body 28a can stretch appropriately without breaking in response to the amount of protrusion of the screw 27 from the inner surface 26c of the housing 26, and to manufacture the sheet body 28a using a material whose limit elongation is greater than this elongation.

[0035] When sheet member 28 is attached to screw hole 26a, the attachment position may shift, resulting in an error between the center of screw hole 26a and the center of sheet member 28. Taking this error into consideration, the elongation rate and the size (diameter, if circular) of sheet member 28 (sheet main body 28a) are determined so that even if the centers of screw hole 26a and sheet member 28 are slightly misaligned (for example, 1.5 mm), the relationship between the expected elongation rate of sheet member 28 due to protrusion of screw 27 and the limit elongation rate is a safety factor of 3 or more. With sheet member 28 as described above, breakage due to protrusion of screw 27 is appropriately suppressed, excellent sealing properties of screw hole 26a are obtained, and excellent dustproofing effects can be maintained.

[0036] The adhesive portion 28b is used to adhere and fix the sheet main body 28a to the inner surface 26c of the housing 26. In the first embodiment, the adhesive portion 28b is formed of double-sided tape. That is, as shown in FIG. 4(a), the adhesive portion 28b is composed of, in order from the sheet main body 28a side, a first adhesive layer 28b1, a base material 28b2, a second adhesive layer 28b3, and a release paper 28b4. The first adhesive layer 28b1 is adhered to the sheet main body 28a. The base material 28b2 is a member for holding the first adhesive layer 28b1 and the second adhesive layer 28b3. The second adhesive layer 28b3 is adhered to the housing 26. The release paper 28b4 is a member for protecting the second adhesive layer 28b3. The sheet member 28 can be placed in the housing 26 by peeling off the release paper 28b4 and attaching the second adhesive layer 28b3 to the housing 26 so as to cover the screw holes 26a.

[0037] Note that adhesive portion 28b is not limited to being formed with double-sided tape. As a modified example, adhesive portion 28b may be formed by applying adhesive or hot melt to one surface of sheet main body 28a. That is, as shown in Fig. 4(b), sheet member 28A of the modified example is composed of sheet main body 28a and adhesive portion 28b made of, in order from the sheet main body 28a side, first adhesive layer 28b1 and release paper 28b4.

[0038] Furthermore, adhesive portion 28b has a peel strength (peel adhesive strength) that prevents sheet member 28 from peeling off from inner surface 26c of housing 26 when sheet member 28 is stretched by protruding screws 27. More specifically, adhesive portion 28b is desirably formed by selecting a double-sided tape, adhesive, or the like that has a peel strength that provides a safety factor of 3 or more relative to the modulus when sheet member 28 (main sheet body 28a) is stretched by screws 27. Here, "peel strength" refers to the specifications of adhesive materials such as double-sided tape, and is, for example, a value measured in accordance with JIS Z0237. "Modulus" refers to the force that attempts to return to its original shape when pulled (the specifications of main sheet body 28a).

[0039] Below, the procedure for calculating the elongation rate of the sheet member 28 of the first embodiment (the elongation rate when the sheet member 28 is elongated due to the protrusion of the screw 27 threaded into the screw hole 26a), and the relationship between the calculated elongation rate and the limit elongation rate will be explained, along with the action and effect of the sheet member 28.

[0040] First, when sheet member 28 is attached to inner surface 26c of housing 26, burring portion 26d protruding inward at height h leaves a portion of sheet member 28 unbonded to inner surface 26c, and an area near the outer periphery of sheet member 28 (hereinafter referred to as "bonding area A") is bonded annularly to inner surface 26c, while an area near the center of sheet member 28 (hereinafter referred to as "bonding area B") is bonded to the top surface of burring portion 26d. As a result, screw holes 26a are sealed from the inside by sheet member 28.

[0041] When the screw 27 is screwed into the screw hole 26a during assembly of the ophthalmic device 1, the screw 27 protrudes, causing the sheet member 28 to stretch inward, as shown in FIG. 3(b). At this time, the adhesive region A is fixed to the inner surface 26c and hardly stretches. On the other hand, the portion of the adhesive region B that contacts the tip of the screw 27 (the region facing the screw hole 26a) is fixed to the screw 27 and hardly stretches. Therefore, the region between the adhesive region A and the portion of the adhesive region B that contacts the tip of the screw 27 (hereinafter referred to as "stretching region C") mainly stretches.

[0042] 3(b), the reference length L0 of the stretched region C of the sheet member 28 in the radial direction before the stretched region C is stretched is calculated by the following formula (1): In the following formula (1), D0 is the diameter (outer diameter) of the sheet member 28, a is the radial attachment width of the adhesive region A near the outer peripheral edge attached to the inner surface 26c of the housing 26, and d0 is the nominal diameter (outer diameter) of the screw 27.

[0043]

number

[0044] 3(b), the radial length L1 of the stretched region C of the sheet member 28 when the stretched region C is stretched can be calculated by the following formula (2): In this formula (2), L0 is the reference radial length of the stretched region C before stretching calculated by formula (1), and H is the amount (height) of the screw 27 protruding from the attachment surface of the sheet member 28 (in the example of FIG. 3(b), the inner surface 26c of the housing 26).

[0045]

number

[0046] Therefore, the elongation rate of the stretched region C, i.e., the elongation rate T (%) of the sheet member 28, is calculated by the following formula (3): In the following formula (3), L0 is the reference radial length of the stretched region C before stretching, and L1 is the radial length of the stretched region C when stretched.

[0047]

number

[0048] As described above, if the elongation rate T is less than the limit elongation rate of the sheet member 28 (sheet body 28a) (elongation rate T<limit elongation rate), the sheet member 28 will smoothly elongate and maintain the sealing state of the screw hole 26a without causing breakage or perforation due to the protrusion of the screw 27. Therefore, it is possible to appropriately prevent the intrusion of metal chips through the screw hole 26a.

[0049] As described above, according to the first embodiment, it is possible to provide a sheet member 28 and an ophthalmic device 1 equipped with the sheet member 28 that can appropriately prevent dust, metal chips, etc. from entering the housing 26 and have excellent dustproofing properties.

[0050] Furthermore, in the ophthalmologic device 1 of this embodiment, the sheet member 28 can appropriately prevent not only dirt and dust but also metal chips caused by the screw 27 from entering the inside of the housing 26 during assembly, eliminating the need for a cleaning window in the housing as in the past. This also reduces the effort required for cleaning. Furthermore, even if the screw 27 comes loose, the sealing action of the sheet member 28 can prevent dirt and other particles from entering the inside of the housing 26 through the screw hole 26a. Furthermore, even if the screw 27 is retightened, the sheet member 28 still appropriately prevents metal chips from entering the inside of the housing 26.

[0051] (Second embodiment) The ophthalmic device 1 and sheet member 28B according to the second embodiment will be described below with reference to Fig. 5. The ophthalmic device 1 according to the second embodiment has the same basic configuration as the first embodiment shown in Fig. 1 and the like, except that the sheet member 28B shown in Figs. 5(a) and 5(b) is used instead of the sheet member 28 adhered to the housing 26, and therefore a detailed description thereof will be omitted. The following description will mainly focus on the sheet member 28B.

[0052] 5(a), the sheet member 28A of the second embodiment is composed of a circular sheet body 28a and a flange-shaped (donut-shaped) adhesive portion 28b. The sheet body 28a may be the same as the sheet body 28a of the first embodiment.

[0053] Similar to the first embodiment, the adhesive portion 28b of the second embodiment can be formed using double-sided tape, adhesive, or the like, except that it has a flange-like (donut-like) shape. More specifically, as shown in FIG. 5(b), the adhesive portion 28b is composed of, in order from the sheet main body 28a side, a first adhesive layer 28b1, a base material 28b2, a second adhesive layer 28b3, and a release paper 28b4. The adhesive portion 28b may also be composed of the first adhesive layer 28b1 and the release paper 28b4, as in the modified example shown in FIG. 4(b).

[0054] According to the second embodiment, by disposing the sheet member 28 on the housing 26 of the ophthalmologic device 1, as in the first embodiment, it is possible to appropriately prevent not only the intrusion of dirt and dust but also the intrusion of metal chips into the housing 26 due to the fastening of the screws 27. Furthermore, in the second embodiment, by providing the flange-shaped (donut-shaped) adhesive portion 28b, only the area (adhesive area A) near the outer periphery of the sheet member 28 is fixed to the inner surface 26c. Therefore, even if the protrusion amount of the screw hole 26a is small, the extension area C is prevented from adhering to the inner surface 26c, and the extension area C can stretch more smoothly. This makes it possible to appropriately prevent breakage or perforation, and also reduces the amount of material required for the adhesive portion 28b, thereby reducing the manufacturing cost of the sheet member 28. [Example]

[0055] A sheet member 28 of Example 1 was produced with the same configuration as in the first embodiment using the materials and dimensions shown below, and its elongation was calculated. Note that the sheet member 28 of Example 1 is just an example, and the sheet member 28 is not limited to the structure of Example 1.

[0056] Silklon (registered trademark, model number: SNY97-CLB 40 μm) manufactured by Okura Kogyo Co., Ltd. was used as the sheet body 28a of the sheet member 28 in Example 1. The sheet body 28a in Example 1 is configured by sandwiching a non-yellowing urethane (polyurethane) film between two PET films. The sheet body 28a has a thickness of 40 μm and a limit elongation of 395% (at 20°C) measured by a method in accordance with JIS K7311.

[0057] Double-sided tape (model number: T4412WP) manufactured by Dexerials Corporation was used as adhesive portion 28b of sheet member 28 in Example 1. In adhesive portion 28b in Example 1, base material 28b2 is PET, and first and second adhesive layers 28b1, 28b3 are mainly made of acrylic resin. The thickness from first adhesive layer 28b1 to second adhesive layer 28b3 is approximately 55 μm, and the thickness of release paper 28b4 is approximately 75 μm.

[0058] 3(a) or 3(b) has a diameter D0 of 10 mm, and a width a of the adhesive area A of 1.0 mm. The nominal diameter d0 of the screw 27 is 3.0 mm, the height h of the screw hole 26a is 1.0 mm, and the amount by which the screw 27 protrudes from the inner surface 26c of the housing 26 is 2.0 mm or less (i.e., a maximum of 2.0 mm).

[0059] When the above numerical values ​​are applied to the above formulas (1) to (3), the following results are obtained. L0 = (10.0 - 2 x 1.0) / 2 - 3.0 / 2 = 2.5 L1=√(2.5 2 +2.0 2 )=3.2 ∴Elongation rate T = (3.2 - 2.5) / 2.5 x 100 = 28% (<395%)

[0060] Here, when the attachment position of the sheet member 28 is shifted and an error of 1.5 mm occurs between the center of the screw hole 26a and the center of the sheet member 28, the elongation rate is calculated as follows. L0=2.5-1.5=1.0 L1=√(1.0 2 +2.0 2 )≒2.24 ∴Elongation rate T = (2.24 - 1.0) / 1.0 x 100 = 124% (<395%)

[0061] From the above, even when the centers of screw holes 26a and sheet member 28 are aligned, or when there is an error of about 1.5 mm, the elongation of sheet member 28 is less than the critical elongation. This shows that sheet member 28 of Example 1 can suppress breakage or perforation caused by protruding screws 27, achieve a high dustproof effect, and provide an excellent effect of preventing dirt, dust, and metal chips from entering the inside of housing 26.

[0062] The ophthalmic device 1 of the present disclosure has been described above based on embodiments, modifications, and examples, but the specific configuration is not limited to these, and design changes and additions are permitted as long as they do not deviate from the gist of the invention according to each claim in the scope of the claims.

[0063] In each of the above-described embodiments, modifications, and examples, the ophthalmologic apparatus 1 has, as optical systems, two left and right measurement optical systems (a right measurement optical system 25R and a left measurement optical system 25L) each having an observation system for observing the anterior segment of the eye to be examined, a fixation target projection system for presenting a fixation target to the eye to be examined, an objective measurement system for irradiating measurement light onto the fundus of the eye to be examined and receiving reflected light of the measurement light reflected by the fundus of the eye to be examined, a subjective measurement system for presenting a subjective target to the eye to be examined, etc. However, the ophthalmologic apparatus of the present disclosure is not limited to this configuration, and the optical system may be configured to have only one of the objective measurement system and the subjective measurement system. The ophthalmic device may also be a visual acuity testing device that performs a visual acuity test while switching between presented optotypes, a phoropter that switches and positions corrective lenses to obtain the appropriate corrective refractive power of the subject's eye, a refractometer or wavefront sensor that measures refractive power, a fundus camera that takes images of the fundus, an optical coherence tomography (OCT) device that takes tomographic images of the retina, a specular microscope that takes images of the corneal endothelium, a keratometer that measures corneal shape, or a tonometer that measures intraocular pressure. The ophthalmic device may also be a combination of multiple such ophthalmic devices. The housing of these ophthalmic devices may be configured to have screw holes and a sheet member placed on one surface of the interior of the housing to cover the screw holes, thereby appropriately preventing dust, metal chips from the screws used during assembly, and the like from entering the interior of the housing.

[0064] Furthermore, although the ophthalmologic apparatus 1 in each of the above-described embodiments, modifications, and examples includes the right measurement optical system 25R and the left measurement optical system 25L as optical systems, the present invention is not limited to this configuration and may include a single optical system to measure ocular characteristics one eye at a time. Furthermore, the housing 26 and / or the screws 27 are not limited to being made of metal but may be made of hard resin, etc. Even in this case, by placing the sheet member 28 in the screw hole 26a, it is possible to appropriately prevent metal chips, resin chips, etc., from entering the inside of the housing 26 due to friction between metals, between metals and resins, or between resins when the screws 27 are screwed into the screw hole 26a.

[0065] Furthermore, sheet member 28 may be attached to the top surface of burred portion 26d, or to the top surface and outer peripheral surface of burred portion 26d (the top surface and outer peripheral surface are also included in one surface on the interior side of housing 26), and does not necessarily have to cover the entire burred portion 26d. Furthermore, burred portion 26d does not have to be provided on housing 26, and screw hole 26a may simply be a screw hole drilled in the wall surface of housing 26. Furthermore, a nut and a washer into which screw 27 is threaded may be disposed inside housing 26, and sheet member 28 may cover screw hole 26a together with the nut and washer. Furthermore, a relief hole for screw 27 may be formed in housing 26, and sheet member 28 may be attached so as to cover screw hole 26a including the relief hole. [Explanation of symbols]

[0066] 1:Ophthalmological equipment 25L: Left measurement optical system (optical system) 25R: Right measurement optical system (optical system) 26: Housing 26L: Housing 26R: Cabinet 26B: Sheet member 26a: screw hole 27: Bis 28: Sheet material 28B: Sheet member 28a: Seat body 28b: Adhesive part

Claims

1. An optical system having an optical element for acquiring ocular characteristics of a subject's eye; a housing that houses the optical system, the housing has screw holes and a sheet member disposed on one surface of an inner side of the housing so as to cover the screw holes, The sheet member has an elongation rate less than the limit elongation rate of the sheet member when a screw is inserted into the screw hole. An ophthalmic device characterized by:

2. An optical system having an optical element for acquiring ocular characteristics of a subject's eye; a housing that houses the optical system, the housing has screw holes and a sheet member disposed on one surface of an inner side of the housing so as to cover the screw holes, The sheet member has a circular or elliptical shape in a plan view. An ophthalmic device characterized by:

3. A sheet member used in an ophthalmologic apparatus including an optical system having an optical member for acquiring ocular characteristics of a subject's eye, and a housing for accommodating the optical system, The sheet member has a sheet body and an adhesive portion provided on one surface of the sheet member, the housing of the ophthalmic device is disposed on one surface of the inner side of the housing so as to cover a screw hole formed in the housing, The elongation rate of the sheet member when a screw is inserted into the screw hole is less than the limit elongation rate of the sheet member. A sheet member characterized by:

Images