Perimeter

Abstract

To provide a perimeter provided with an alternative to a conventional light source used in a conventional perimeter.SOLUTION: A perimeter comprises: a light-receiving body 10 having a spherical concave light-receiving surface 12; an LED unit 40 in which an LED 46 is housed, the LED being a light source for irradiating the light-receiving surface 12 of the light-receiving body 10 with internal light and for irradiating an arbitrary position on the light-receiving surface 12 of the light-receiving body 10 with spot light; and a moving member 80 which is optically connected to the LED unit 40, comprises a projector 82 for irradiation with spot light, and moves the projector 82 so that an arbitrary position on the light-receiving surface 12 is irradiated with the spot light.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a perimeter capable of measuring the visual field of a subject. [Background technology]

[0002] Perimeters have been used as the basic testing device for visual field measurement. Below is an overview of an example of a conventional perimeter.

[0003] That is, a perimeter such as that shown in Patent Document 1 (JP 2004-229870 A) includes a dome-shaped photoreceptor with a reference point at its center, a light source, and a projector that projects light from the light source onto the inner surface of the photoreceptor as spot light. In such a perimeter, the subject gazes at the reference point and tells the examiner whether or not the spot light at each position can be confirmed in the subject's field of view, allowing the examiner to measure the subject's visual field. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-229870 Summary of the Invention [Problem to be solved by the invention]

[0005] The conventional perimeters described above use incandescent lamps such as tungsten lamps (hereinafter sometimes referred to as "conventional light sources") as the main light source for illuminating the projector and the interior of the photoreceptor, and employ a configuration in which the light from the incandescent lamp is concentrated by a condenser lens and then irradiated from the projector. However, the following problems arise with perimeters using conventional light sources.

[0006] First, the market supply of conventional light sources has been decreasing year by year, raising the issue of future inability to secure a source of light for perimeter testing. Second, conventional light sources have electrical problems, such as high currents, resulting in carbon deposits on the bulb contacts. Third, conventional light sources have a problem of heat generation, which can lead to dirt settling on the condenser lens. Fourth, conventional light sources require several minutes of aging before the light output stabilizes. Fifth, conventional light sources have a problem of filament deformation due to heat generation, resulting in misalignment of the optical axis. Sixth, conventional light bulbs have a lifespan of only a few dozen hours, necessitating frequent bulb replacement. Seventh, conventional light sources generate a large amount of heat, which raises the temperature of the exterior, which may be in contact with the patient. Eighth, conventional light sources have unstable light output across multiple days, requiring adjustments for each test day. Thus, an alternative to conventional light sources is needed for conventional perimeter testing. [Means for solving the problem]

[0007] The present invention has been made in view of the above circumstances, and has as its object to provide a perimeter equipped with an alternative to the conventional light source used in conventional perimeters.

[0008] The present invention solves the above problems by the solution means described below as one embodiment.

[0009] In other words, the disclosed perimeter is required to include a photoreceptor having a spherical-concave light-receiving surface, an LED unit that houses an LED as a light source that irradiates internal light onto the light-receiving surface of the photoreceptor and irradiates spot light at any position on the light-receiving surface of the photoreceptor, and a moving member that is optically connected to the LED unit and is provided with a projector for irradiating the spot light, and that moves the projector so that the spot light irradiates any position on the light-receiving surface.

[0010] Preferably, the LED unit has an LED base on which the LED is mounted, and a housing having a through hole through which the LED base can be inserted.

[0011] Furthermore, it is preferable that the LED unit has an annular socket base that is provided on the outer edge of the through hole and that holds the LED base.

[0012] Furthermore, it is preferable that the LED base is a member formed in the shape of a half cylinder, the LED being mounted on the flat half, and a heat dissipation portion consisting of slits being formed on the curved half.

[0013] Furthermore, it is preferable that the light source further comprises a control unit having a conversion circuit that converts the power supplied to the LED from AC to DC, an adjustment knob for adjusting the light intensity of the LED, and an LED indicator, and that the control unit is arranged so that the LED indicator faces the back surface of the light receiver, opposite the light receiving surface.

[0014] Furthermore, the control unit is preferably configured to be retrofittable to known perimeters having conventional light sources.

[0015] Furthermore, it is preferable that the device further comprises a light meter for measuring the illuminance of the spotlight, and that the LED indicator converts the illuminance of the light received by the light meter into brightness and displays it.

[0016] Furthermore, it is preferable that the device is provided with an operation panel, which is capable of controlling the amount of supply to the LED so that the brightness of the spotlight is set to 20 levels of brightness, namely 1x, 0.8x, 0.63x, 0.5x, 0.4x, 0.315x, 0.25x, 0.2x, 0.16x, 0.125x, 0.1x, 0.08x, 0.063x, 0.05x, 0.04x, 0.0315x, 0.025x, 0.02x, 0.016x, or 0.0125x, or a brightness of 0.01x or 0.0001x the brightness of each of the levels.

[0017] Furthermore, it is preferable that the color temperature of the light from the LED is 2600 K to 3300 K. Furthermore, it is preferable that a filter is further provided immediately above the light path of the LED, and that the filter reduces the peak illuminance of at least the wavelength of 435 nm to 455 nm of the LED wavelengths to 55% or less, and that the transmittance of wavelengths of 460 nm to 700 nm is 90% or more. [Effects of the Invention]

[0018] According to the above disclosure, it is possible to realize a perimeter equipped with a light source that can replace the conventional light sources used in conventional perimeters. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is an overall view of a perimeter seen from the subject side in a first embodiment of the present invention. FIG. [Figure 2] FIG. 1 is an overall view of a perimeter seen from the examiner's side in a first embodiment of the present invention. [Figure 3] 1 is an exploded perspective view of an LED unit according to a first embodiment of the present invention, viewed from above. FIG. [Figure 4] FIG. 4 is a perspective view of the LED unit of FIG. 3 from the rear. [Figure 5] 1 is an exploded perspective view of the LED unit according to the first embodiment of the present invention, viewed from below. FIG. [Figure 6] 1 is a graph showing wavelength characteristics of a conventional light source and an LED. [Figure 7] 1 is a block diagram of a first embodiment of the present invention. [Figure 8] FIG. 10 is an overall view of a perimeter seen from the examiner's side in a second embodiment of the present invention. [Figure 9] FIG. 10 is a block diagram of a second embodiment of the present invention. [Figure 10] FIG. 10 is a partial schematic cross-sectional view of a perimeter in a third embodiment of the present invention. [Figure 11]FIG. 10 is an explanatory diagram illustrating the characteristics of a filter according to a third embodiment of the present invention. [Figure 12] FIG. 10 is an explanatory diagram illustrating the effect of the No. 1 filter in the third embodiment of the present invention. [Figure 13] FIG. 10 is an explanatory diagram showing the effect of the No. 2 filter in the third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] Each embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an overall view of a perimeter 200 according to a first embodiment of the present invention, as seen from the patient's side. FIG. 2 is an overall view of a perimeter 200 according to a first embodiment of the present invention, as seen from the examiner's side. FIG. 3 is an exploded perspective view of an LED unit 40 according to a first embodiment of the present invention, as seen from above. FIG. 4 is a perspective view of the LED unit 40 of FIG. 3, as seen from the back. FIG. 5 is an exploded perspective view of an LED unit 40 according to a first embodiment of the present invention, as seen from below. FIG. 6 is a graph showing the wavelength characteristics of a conventional light source and an LED 46. FIG. 7 is a block diagram according to a first embodiment of the present invention. In all drawings used to explain each embodiment, components having the same function are designated by the same reference numerals, and repeated description thereof may be omitted.

[0021] First Embodiment <<Summary>> 1 and 2, the perimeter 200 in the first embodiment includes a photoreceptor 10, an LED unit 40, and a movable member 80. That is, the perimeter 200 is intended to be used by a subject and an examiner who face each other across the photoreceptor 10. The examiner moves the movable member 80 (particularly, moves it behind the subject) to irradiate the inside of the photoreceptor 10 with spot light emitted from the LED 46 as a light source. The subject can then notify the examiner whether or not the spot light irradiated inside the photoreceptor 10 can be confirmed in the subject's visual field, thereby measuring the subject's visual field.

[0022] In particular, the perimeter 200 in the first embodiment can adopt the same configuration as a conventional perimeter, except for the LED unit 40 and the control unit 76 (including the adjustment knob 76a, conversion circuit 76c, and dimming circuit 76d).

[0023] <<Photoreceptor>> The light receiver 10 has a spherically concave light receiving surface 12 and a main body 20. The light receiving surface 12 is formed as a dome-shaped recess (spherical recess) on the side of the rectangular parallelepiped main body 20. In particular, the light receiving surface 12 is formed so as to extend to both sides of the main body 20.

[0024] Furthermore, the photoreceptor 10 is formed, for example, from a resin material or a metal material (for example, an aluminum alloy), and the light receiving surface 12 and the main body 20 are integrally molded, but is not limited to this. Furthermore, the light receiving surface 12 is formed, for example, in the shape of a hemispherical dome with a diameter of about 1 m, and the main body 20 is formed narrower and taller than the light receiving surface 12, but is not limited to this.

[0025] Furthermore, a reference point 18 is provided at the center of the light receiving surface 12. The reference point 18 is a point that serves as an index for the subject to gaze at when performing visual field measurement. Multiple reference points 18 may be provided. By changing the reference point that the subject gazes at to the left, right, top, or bottom and reducing the dome radius of the light receiving surface 12, the perimeter 200 can be made smaller.

[0026] Furthermore, slits 14 and 16 are formed on the left and right sides of the outer edge of the light-receiving surface 12. The slits 14 and 16 are formed so that a projector 82 (described later) can be inserted therethrough, thereby enabling spot light to be emitted up to the vicinity of the outer edge of the light-receiving surface 12.

[0027] <<Support>> A support 30 having a chin rest 32 is provided at the bottom of the main body 20. That is, the support 30 is provided at a position where the subject can face the light receiving surface 12 when the subject places his or her chin on the chin rest 32. The chin rest 32 is provided so as to be movable up and down relative to the support 30, allowing the height of the subject's line of sight to be adjusted appropriately. It is preferable that the height of the chin rest 32 be adjusted so that the reference point 18 is located in the center of the subject's field of vision when the subject faces forward.

[0028] <<<Notification button>>> A notification button 22 is provided on the bottom of the main body 20. When the subject can see the spot light irradiated at any position on the light receiving surface 12 in his or her field of vision, the subject can press the notification button 22 to notify the examiner of this.

[0029] <<LEDユニット> > The LED unit 40 houses an LED (Light Emitting Diode) 46, which is a light source that irradiates the interior of the photoreceptor 10 (i.e., the light receiving surface 12) with internal light and irradiates a spot light at any position on the light receiving surface 12. As an example, the LED unit 40 is provided outside the photoreceptor 10, at an upper position above the light receiving surface 12 (particularly, at an upper inner position above the light receiving surface 12 when the photoreceptor 10 is viewed from the front).

[0030] The LED unit 40 also has an LED base 44 on which an LED 46 is mounted, a retainer 52, a lamp cover 56, and a housing 60 in which a through hole 62 through which the LED base 44 can be inserted is formed.

[0031] <<<Case>>> 3 and 4, the housing 60 has through holes 62 formed in the front-to-rear direction (i.e., from the opening 62a on the side where the LED base 44 is inserted toward the opening 62b on the light-receiving surface 12 side). Therefore, the housing 60 allows light from the LEDs 46 to be irradiated as internal light onto the light-receiving surface 12 from the opening 62b. In addition, it is preferable that a light-diffusing paint is uniformly applied to the surface of the light-receiving surface 12, so that the light emitted from the opening 62b can uniformly illuminate the light-receiving surface 12.

[0032] <<<<Condenser Lens>>>> A condenser lens 66 is provided on the upper part of the housing 60. The condenser lens 66 condenses the light from the LEDs 46, and allows a spot light to be irradiated onto the light receiving surface 12 from a projector 82, which will be described later.

[0033] The area of the spot light (i.e., the area of the spot light projected onto the light receiving surface 12) is 64 mm 2 , 16mm 2 , 4mm 2 , 1mm 2 , 1 / 4mm 2 , and 1 / 16 mm 2 The area of the spot light of the condenser lens 66 can be changed appropriately by moving a perforated disk (not shown) placed on top of the condenser lens 66 with an operating lever 106.

[0034] The housing 60 is formed of a metal material (aluminum alloy, etc.) as an example, but is not limited to this.

[0035] Furthermore, the opening 62a is formed to a size that can accommodate a tungsten bulb, which is a conventional light source. Therefore, it is possible to remove the tungsten bulb from the perimeter 200 that uses a tungsten bulb, which is a conventional light source, and install the LED base 44. In this case, the conventional perimeter can easily be converted into the perimeter 200 of this embodiment.

[0036] <<<Socket-based>>> Furthermore, a ring-shaped socket base 64 with an inner diameter of several centimeters that holds the LED base 44 is attached to the outer edge of the opening 62a of the through-hole 62. More specifically, the socket base 64 is screwed to one surface of the housing 60 that includes the opening 62a. Furthermore, the inner diameter of the socket base 64 is preferably larger than the outer diameter of the half-cylindrical shape of the LED base 44, which allows the LED base 44 to be inserted through the socket base 64 and the housing 60.

[0037] The socket base 64 is formed from a heat-resistant resin, for example, but is not limited to this.

[0038] <<<Slide cover>>> Furthermore, a sliding cover 68 is provided on the surface of the housing 60 on the opening 62b side so as to be movable up and down. The sliding cover 68 is formed, for example, in the shape of a half cylinder. The sliding cover 68 functions as a light blocking member for the LEDs 46 that emit light inside the housing 60. By moving the sliding cover 68 up and down relative to the housing 60, the opening amount of the opening 62b is adjusted, and thereby the brightness of the internal light irradiated onto the light receiving surface 12 can be adjusted.

[0039] The brightness can be adjusted to 10 cd / m 2 (31.5asb) and the standard spot light luminance (318.3cd / m 2 A spot light of 0.0315 times (1000asb)) is irradiated onto the light receiving surface 12, and the opening size of the opening 62b is changed by moving the slide cover 68 up and down so that the brightness of the spot light on the light receiving surface 12 and the brightness of the internal light are approximately the same.

[0040] <<<LEDベース> >> 3 and 5, the LED base 44 is, for example, a member formed in the shape of a half cylinder from a metal material (such as an aluminum alloy). An LED substrate 44a on which an LED 46 is mounted is provided on a half flat portion of the half cylinder, and the LED 46 and the condenser lens 66 are provided coaxially (so that the LED 46 and the condenser lens 66 face each other).

[0041] The LED board 44 a (that is, the LEDs 46 ) is connected to a control unit 76 via a cable 74 .

[0042] The perimeter 200 includes an LED unit 40 housing an LED 46, providing the following advantageous effects. Specifically, it can function as a light source replacement when conventional perimeter light sources are no longer available on the market. It also prevents carbon buildup on the bulb contacts, eliminating electrical problems. Furthermore, LEDs generate less heat than conventional light sources, preventing dirt from building up on the condenser lens 66. Furthermore, LEDs do not require as much aging time to stabilize their light output as conventional light sources, thereby shortening the inspection time using the perimeter 200. Furthermore, LEDs do not suffer from filament deformation like conventional light sources, eliminating misalignment of the optical axis. Furthermore, while conventional light bulbs have a lifespan of several tens of hours and require frequent bulb replacement, LEDs have a long lifespan of tens of thousands of hours, eliminating the need for frequent bulb replacement. Furthermore, the low heat generated by LEDs prevents the entire LED unit 40, especially the exterior that may come into contact with the subject, from overheating. Furthermore, the light output of LEDs is stable, and even when the system is turned on and off over the course of a day, the light output remains stable. Therefore, while light output adjustment is required every time an inspection is carried out using conventional light sources such as incandescent bulbs, with LEDs it only needs to be done every few months.

[0043] The color temperature of the LED 46 is preferably 2600K to 3300K.

[0044] <<<<Heat dissipation section>>>> Furthermore, a heat dissipation section consisting of slits 50 is formed in the curved surface portion (side surface portion of the half cylinder) 48 of the half cylinder shape of the LED base 44. As shown in Fig. 5, the LED base 44 in this embodiment has five slits 50 formed parallel to each other and spaced at equal intervals, but this is not limited to this. By forming the slits 50 in the LED base 44, heat generated from the LEDs 46 can be dissipated, thereby suppressing temperature rise in the LEDs, which are sensitive to heat, and improving the lifespan of the LEDs.

[0045] <<<Hold>>> The presser foot 52 is attached to the LED base 44 (for example, by screwing) and fixed to the socket base 64. An engagement claw 52a is formed on the presser foot 52, and after aligning it with an engagement portion (not shown) provided on the inner periphery of the socket base 64, for example, the presser foot 52 can be engaged with the socket base 64 by gripping a knurled knob 54 and rotating the presser foot 52. In other words, the presser foot 52 is formed so that it can be aligned so that the LED 46 and the condenser lens 66 are coaxial (so that the LED 46 and the condenser lens 66 face each other) when engaged with the socket base 64.

[0046] The presser 52 is made of a metal material, for example, but is not limited to this.

[0047] <<<Lamp cover>>> The lamp cover 56 is formed in a cap shape using a resin material, for example, and the socket base 64 is inserted into the lamp cover 56. The lamp cover 56 can be fixed in place by abutting the cover holder 70 against the holder 58.

[0048] The perimeter 200 also includes an indicator 96 that displays the illuminance of the spotlight emitted from the projector 82 as brightness, a conversion circuit 76c that converts the power supplied to the LEDs 46 from AC to DC, and a control unit 76 that has an adjustment knob 76a for adjusting the light intensity of the LEDs 46. A cable 74 connected to the control unit 76 is connected to the LED board 44a (i.e., the LEDs 46) through through holes provided in the lamp cover 56 and the retainer 52. The control unit 76 is also connected to a power source (AC power source).

[0049] <<Indicator>> The indicator 96 is provided on the rear surface of the main body 20 (i.e., on the examiner side) and is connected to a light meter 98 via a cable 100. The light meter 98 is provided at the innermost part of the slit 16 and is configured to receive spot light emitted from the projector 82 located inside the slit 16 and measure the illuminance thereof. The indicator 96 is configured to convert the illuminance measured by the light meter 98 into brightness and display it.

[0050] 6, conventional light sources (e.g., tungsten light bulbs) and LED 46 have different wavelength characteristics. Specifically, the conventional light source (tungsten light bulb) and LED 46 have different effective light receiving areas in the light receiving sensitivity characteristics of light meter 98, and the effective area of the LED is smaller than the effective area of the conventional light source (light bulb). Therefore, the value indicated by indicator 96 is smaller for LED 46 than for the conventional light source (light bulb), so it is preferable to readjust indicator 96, which is designed specifically for conventional light sources, for use with LED 46.

[0051] <<Control unit>> The control unit 76 is formed as a housing using, for example, a resin material, and is configured such that by adjusting an adjustment knob 76a, a light control circuit 76d provided inside the control unit 76 controls the light intensity of the LED 46. To improve visibility in a dark room, a pilot lamp 76e is connected to the control unit 76, which can illuminate the outline of the adjustment knob 76a.

[0052] It is preferable that the control unit 76 is provided near the indicator 96. More specifically, it is preferable that the surface on which the adjustment knob 76a of the control unit 76 is provided is flush with the surface on which the indicator 96 of the main body 20 is provided. This allows the examiner to adjust the brightness while performing visual field measurement without moving.

[0053] Furthermore, the control unit 76 is preferably configured to be retrofittable to a known perimeter having a conventional light source (e.g., Takagi Seiko Corporation's Projection Perimeter, Model MT-325UD). A socket (not shown) connected to a power source (AC power supply) is provided on the side of the main body 20 of the perimeter near the indicator 96. Furthermore, a socket pin (not shown) is provided on the side of the control unit 76, which is inserted into the socket and connected to a conversion circuit 76c (described later). As described above, when replacing the conventional light source in a known perimeter with an LED 46, the LED 46 can be connected to a power source (AC power supply) via the control unit 76 that can be attached to the known perimeter. This allows the perimeter 200 equipped with the LED 46 to be realized without modifying the perimeter itself having a conventional light source.

[0054] <<<Conversion circuit>>> As shown in FIG. 7, a conversion circuit 76c is provided inside the control unit 76, which can convert the power supplied to the LEDs 46 from AC power (i.e., AC power supplied to conventional light sources (tungsten bulbs)) to DC. The AC power supplied to conventional light sources (tungsten bulbs) varies between approximately 4V AC and 10V AC, but the conversion circuit 76c can supply this as a stable DC power to the LEDs 46. When a conventional light source is used in the perimeter, it can be used with AC power supply, but when the perimeter light source is replaced with LEDs 46, it is preferable to use DC power supply. By providing the conversion circuit 76c in the perimeter 200, conventional light sources can be easily replaced with LEDs.

[0055] Next, the moving member 80 of the perimeter 200 in the first embodiment will be described. The perimeter 200 includes the moving member 80 and a connecting portion 90 related to the operation of the moving member 80. The moving member 80, the projector 82, the rotating link 84, the connecting portion 86, and the rotating member 88 can have the same configuration as that of a known perimeter.

[0056] <<Moving parts>> The moving member 80 is connected to a rotating member 88 provided on the upper part of the main body 20 via a rotating link 84 and a connecting portion 86. A projector 82 is provided at the tip of the moving member 80. The rotating member 88 is also connected to a connecting portion 90.

[0057] <<<Projector>>> The projector 82 is configured to irradiate the light from the LED 46, which is condensed by the condenser lens 66, onto the light receiving surface 12 as spot light via the connecting portion 86 and one or more mirrors (not shown) inside the moving member 80.

[0058] <<<Connection section>>> The connecting part 90 is configured as a link mechanism. A pointer 92 is attached to the tip of the connecting part 90, and the pointer 92 is configured to be movable on a visual field scale display part 94 provided on the back surface of the main body part 20.

[0059] The mechanisms of the moving member 80 and the projector 82 will be described below.

[0060] When the examiner moves the pointer 92 left and right, the rotating member 88 is rotated in the horizontal plane (i.e., in the direction of arrow A in Figure 1) via the connecting part 90, and the moving member 80 is rotated around the photoreceptor 10 with the rotating member 88 as the center of rotation.

[0061] Furthermore, when the examiner moves the pointer 92 up and down, the pivoting link 84 is rotated around its own axis (in the direction of arrow B in FIG. 1) via the connecting part 90 and the pivoting member 88, and the projector 82 is tilted up and down (in the direction of arrow C in FIG. 1) by the vertical movement mechanism inside the moving member 80 and the rack and pinion (neither of which are shown).

[0062] As described above, by combining the left-right movement of the pointer 92 with the up-down movement, the movement of the pointer 92 on the field of view scale display unit 94 can be made to correspond to the movement of the spot light irradiated onto the light receiving surface 12.

[0063] In actual visual field measurement, the examiner moves pointer 92 to a predetermined position on visual field scale display unit 94, and each time the subject moves, he or she notifies the examiner using notification button 22 whether or not the spot light irradiated on light receiving surface 12 and corresponding to the position of pointer 92 can be confirmed in the subject's visual field. Then, the examiner touches the position of pointer 92 on visual field scale display unit 94 (for example, a visual field scale display unit in the form of a touch panel) to store in a storage unit (not shown) whether or not the subject can see that position. This process is repeated for all predetermined spot light irradiation positions, thereby completing the visual field measurement of the subject.

[0064] Second Embodiment Next, the perimeter 200 in the second embodiment will be described in detail. Fig. 8 is an overall view of the perimeter 200 in the second embodiment of the present invention as seen from the examiner's side. Fig. 9 is a block diagram of the second embodiment of the present invention. In the second embodiment, the same members as those in the first embodiment are denoted by the same reference numerals.

[0065] <<Summary>> The perimeter 200 in the second embodiment has an additional configuration to the perimeter 200 in the first embodiment. That is, the perimeter 200 in the second embodiment further includes an operation panel 102 and a spot light irradiation switch 104. Also, the control unit 76 in the second embodiment further includes an LED indicator 76b.

[0066] <<LEDインジケータ> > The control unit 76 in the second embodiment preferably further includes an LED indicator 76b dedicated to the LED 46. As described above in the first embodiment, the wavelength characteristics of a conventional light source (tungsten bulb) and the LED 46 are different, and the effective light receiving range in the light receiving sensitivity characteristics of the light meter 98 is different. Therefore, a dedicated indicator 96 and LED indicator 76b for the conventional light source may be required. The indicator 96 and LED indicator 76b can convert the illuminance of the spot light emitted from the projector 82 into brightness and display it, with the indicator 96 corresponding to the conventional light source and the LED indicator 76b corresponding to the LED 46. In other words, when the light meter 98 receives the spot light from the projector 82 using the conventional light source and displays a brightness of 318.3 cd / m 2 When measuring the illuminance corresponding to the luminance of (1000asb), the needle of indicator 96 reached 318.3cd / m 2It is preferable that the sensitivity is adjusted so that the brightness indicates a brightness of 318.3 cd / m (1000 asb) (e.g., corresponding to the index position provided at the center of the scale). 2 When measuring the illuminance corresponding to the luminance of (1000asb), the needle of LED indicator 76b reached 318.3cd / m 2 It is preferable that the sensitivity is adjusted so that the LED indicator 76b indicates a luminance of 318.3 cd / m (1000 asb) (e.g., corresponding to the position of the indicator provided in the center of the scale). 2 The brightness is adjusted by the adjustment knob 76a so that the brightness becomes (1000asb). The LED indicator 76b is connected to a light meter 98 by a cable 100.

[0067] Furthermore, the control unit 76 is preferably provided near the indicator 96, and further, the LED indicator 76b is preferably provided facing the rear surface of the main body 20 on the opposite side to the light-receiving surface 12 (i.e., the LED indicator 76b faces the examiner). Furthermore, the LED indicator 76b is preferably provided on the same surface as the adjustment knob 76a.

[0068] <<Operation panel>> Preferably, the perimeter 200 further includes an operation panel 102. The operation panel 102 is provided at the bottom of the main body 20 and connected to the control unit 76, and is configured to be able to change the brightness of the light receiving surface 12 (i.e., the light intensity of the LED 46) caused by the spot light of the projector 82 in several stages. More specifically, the operation panel 102 is configured to change the brightness (e.g., 318.3 cd / m) to a reference brightness (e.g., 318.3 cd / m 2After the magnification (1000asb)) is determined using the LED indicator 76b, the amount of DC power supplied to the LED 46 is controlled so that spotlight of 20 levels of brightness, i.e., 1x, 0.8x, 0.63x, 0.5x, 0.4x, 0.315x, 0.25x, 0.2x, 0.16x, 0.125x, 0.1x, 0.08x, 0.063x, 0.05x, 0.04x, 0.0315x, 0.025x, 0.02x, 0.016x, or 0.0125x the brightness of the reference brightness, or 0.01x or 0.0001x the brightness of each of the levels, can be displayed on the light-receiving surface 12. In other words, the inspector can irradiate spotlight of the corresponding brightness by touching a position on the operation panel 102 corresponding to any of the above-mentioned magnifications.

[0069] The perimeter 200 may also be provided with a spot light irradiation switch 104 at the bottom of the main body 20 (below the operation panel 102). Operating the spot light irradiation switch 104 turns the power to the LED 46 on or off, thereby controlling the irradiation of the spot light. The operation panel 102 displays whether the power to the LED 46 is on or off. When using a conventional light source, the brightness of the spot light is changed by inserting or removing several types of ND filters into the illumination light path, thereby switching the brightness of the light-receiving surface 12 due to the spot light irradiated onto the light-receiving surface 12. This is because the light intensity of a conventional light source powered by an AC power source cannot be accurately controlled using the power supplied by the AC power source.

[0070] Third Embodiment Next, the perimeter 300 according to the third embodiment will be described in detail. FIG. 10 is a partial schematic cross-sectional view of the perimeter 300 according to the third embodiment of the present invention. FIG. 11 is an explanatory diagram showing the characteristics of the filter 310 according to the third embodiment of the present invention. FIG. 12 is an explanatory diagram showing the effect of the No. 1 filter 310 according to the third embodiment of the present invention. FIG. 13 is an explanatory diagram showing the effect of the No. 2 filter 310 according to the third embodiment of the present invention. Furthermore, the perimeter 300 according to the third embodiment has the same configuration as the perimeter 200 according to the first or second embodiment, except for the configuration including the filter 310, and the same components as those according to the first and second embodiments are designated by the same reference numerals.

[0071] <<Summary>> Incidentally, visual field defects are known to occur in the middle stage of glaucoma, and more specifically, to begin with a decrease in the sensitivity of S-cones, which are sensitive to relatively short wavelengths (blue wavelengths). That is, early visual field defects are closely related to a decrease in S-cone sensitivity. However, a typical warm white LED has an illuminance peak at a short wavelength (blue wavelength), making it difficult to detect the decrease in S-cone sensitivity. Therefore, in the third embodiment, a specific filter 310 is further provided for the perimeter 200 to suppress the blue wavelengths of the warm white LED, thereby solving the above problem.

[0072] <<filter>> 10 , the perimeter 300 of the third embodiment further includes a filter 310 immediately above the light path of the LED 46, as compared to the perimeter 200 of the first or second embodiment. More specifically, the filter 310 is provided between the LED 46 and the condenser lens 66. Even more specifically, the filter 310 is provided so as to be perpendicular to the light perpendicularly incident from the LED 46. The filter 310 may be provided spaced apart from the LED 46 or in contact with the LED 46. The filter 310 may be attached directly to the LED base 44 or the housing 60, or may be attached to the LED base 44 or the housing 60 via a predetermined member (not shown).

[0073] Filter 310 is a so-called bandpass filter, and is formed, for example, in the shape of a flat plate with vertical and horizontal dimensions of about several centimeters and a thickness of about several millimeters, but is not limited to this and can be appropriately changed depending on the purpose. As another example, filter 310 may be formed in a curved shape (for example, a spherical shape), or may be formed on a dome cover of the LED itself.

[0074] The filter 310 is formed by depositing one or more inorganic films (inorganic multilayer films) such as dielectric films (dielectric multilayer films) on one or both surfaces of a substrate made of a non-metallic material, such as glass, crystal, ceramics, or resin. The dielectric films (dielectric multilayer films) are composed of one or more high-refractive-index layers, one or more low-refractive-index layers, or a combination thereof. Examples of materials for the high-refractive-index layers include zirconium oxide, titanium oxide, tantalum oxide, niobium oxide, hafnium oxide, lanthanum oxide, silicon, or praseodymium oxide, or any combination thereof. Examples of materials for the low-refractive-index layers include silicon oxide, aluminum oxide, calcium fluoride, magnesium fluoride, a combination of aluminum oxide and praseodymium oxide, a combination of aluminum oxide and lanthanum oxide, or a combination of aluminum oxide and tantalum oxide, or any combination thereof.

[0075] Filter 310 is configured to reduce the peak illuminance of at least the wavelengths of 435 nm to 455 nm of the wavelengths of LED 46 to 55% or less, and has a transmittance of 90% or more for wavelengths of 460 nm to 700 nm. By configuring filter 310 as described above, projector 82 can irradiate light receiving surface 12 with spot light that reduces the short wavelengths (blue wavelengths) of the light wavelengths of LED 46 while maintaining the original illuminance characteristics of the red and green wavelengths, thereby making it possible to capture the reduced sensitivity of the subject's S-cone.

[0076] <Example of the third embodiment> Next, an example will be described in which the illuminance of an LED is reduced using a prototype filter 310 of the disclosure. FIG. 11 is a graph showing the wavelength (nm) of light transmitted through each of the two prototype filters 310 and its transmittance (%). For example, the peak illuminance of a short wavelength (blue wavelength) of a typical warm white LED with a light color temperature of 2700K appears around 443 nm, and each of the two prototype filters theoretically reduces this peak illuminance to 55% or less. In addition, the transmittance of wavelengths from 460 nm to 700 nm is 90% or more. In other words, each prototype filter meets the requirements of the disclosed filter 310.

[0077] In this example, calculated and measured values were obtained when the prototype No. 1 and No. 2 filters were used to reduce the illuminance of a typical warm white LED with a light color temperature of 2700 K. The calculated values are reference values calculated by multiplying the illuminance of the LED by the transmittance of the No. 1 and No. 2 filters. The measured values were calculated by measuring the illuminance of the LED light passing through the No. 1 and No. 2 filters. The results are shown in Figures 12 and 13.

[0078] Each line in the graph in Figure 12 represents the wavelength (nm) and absolute irradiance (μW / cm) of a typical tungsten lamp. 2 ), and the wavelength (nm) and absolute irradiance (μW / cm) of a typical incandescent LED with a light color temperature of 2700K. 2 ) and the relationship between wavelength (nm) and absolute irradiance (μW / cm) when the irradiance of the above LED is reduced by the No. 1 filter. 2 ) calculated value, and the wavelength (nm) and absolute irradiance (μW / cm) when the irradiance of the above LED is actually reduced by the No. 1 filter. 2The graph shows the relationship between the measured values of the wavelength (nm) and transmittance (%) of the No. 1 filter. The transmittance of the No. 1 filter for wavelengths from 460 nm to 700 nm remains above 90%, and the measured transmittance also remains above 90%. The transmittance of the No. 1 filter at the wavelength (443 nm) corresponding to the peak irradiance of the LED's blue wavelength is 31.705%. Furthermore, at the wavelength (443 nm) corresponding to the peak irradiance of the LED's blue wavelength, the measured absolute irradiance is 31.555% of the peak irradiance of the LED's blue wavelength. As such, both the calculated and measured values when using the No. 1 filter confirmed that the peak irradiance (irradiance corresponding to the 443 nm wavelength) of the LED's 435 nm to 455 nm wavelength (blue wavelength) can be reduced to 55% or less while maintaining the characteristics of the red and green wavelengths.

[0079] Each line in the graph in Figure 13 represents the wavelength (nm) and absolute irradiance (μW / cm) of a typical tungsten lamp. 2 ), and the wavelength (nm) and absolute irradiance (μW / cm) of a typical incandescent LED with a light color temperature of 2700K. 2 ) and the relationship between wavelength (nm) and absolute irradiance (μW / cm) when the irradiance of the above LED is reduced by the No. 2 filter. 2 ) calculated value, and the wavelength (nm) and absolute irradiance (μW / cm) when the irradiance of the above LED is actually reduced by the No. 2 filter. 2The graph shows the relationship between the measured values of the wavelength (nm) and transmittance (%) of the No. 2 filter. The transmittance of the No. 2 filter for wavelengths from 460 nm to 700 nm remains above 90%, and the measured transmittance also remains above 90%. The transmittance of the No. 1 filter at the wavelength (443 nm) corresponding to the peak irradiance of the LED's blue wavelength is 31.705%. Furthermore, at the wavelength (443 nm) corresponding to the peak irradiance of the LED's blue wavelength, the measured absolute irradiance is 40.716% of the peak irradiance of the LED's blue wavelength. As such, both the calculated and measured values when using the No. 2 filter confirmed that the peak irradiance (irradiance corresponding to the 443 nm wavelength) of the LED's 435 nm to 455 nm wavelength (blue wavelength) can be reduced to 55% or less while maintaining the characteristics of the red and green wavelengths.

[0080] When filter 310 is used in the disclosed perimeter 300, not only the light irradiated from projector 82 but also the internal light that is directly irradiated onto the entire light-receiving surface 12 from opening 62b will be affected by filter 310. Since the wavelength transmission characteristics of the incident light of filter 310 are angle-dependent, they do not match the wavelength characteristics of these lights, but the difference is slight, and it has been confirmed that the light that is directly irradiated onto light-receiving surface 12 does not affect the inspection.

[0081] The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the scope of the present invention. [Explanation of symbols]

[0082] 10 Photoreceptor 12 Photosensitive surface 40 LED units 44 LED base 46 LED 50 Heat dissipation part 60 cabinets 64 socket base 76 Control Unit 76a Adjustment knob 76b LED indicator 76c conversion circuit 80 Moving parts 82 Projector 96 Indicators 98 Light Meter 102 Operation Panel 200 Perimeter 300 Perimeter 310 Filter

Claims

1. a light receiving body having a spherical concave light receiving surface; an LED unit that houses an LED as a light source that irradiates the light receiving surface of the light receiving body with internal light and irradiates a spot light at an arbitrary position on the light receiving surface of the light receiving body; A perimeter characterized by comprising: a projector optically connected to the LED unit for irradiating the spot light; and a movable member for moving the projector so that the spot light is irradiated at any position on the light receiving surface.

2. The LED unit is an LED base on which the LED is mounted; The perimeter according to claim 1 , further comprising a housing having a through hole formed therein through which the LED base can be inserted.

3. The perimeter according to claim 2 , wherein the LED unit has an annular socket base provided on an outer edge of the through hole to hold the LED base.

4. The perimeter according to claim 2 or 3, characterized in that the LED base is a member formed in the shape of a half cylinder, the LED is mounted on the half flat part, and a heat dissipation section consisting of a slit is formed in the curved part.

5. a control unit having a conversion circuit for converting the power supplied to the LED from AC to DC, an adjustment knob for adjusting the light intensity of the LED, and an LED indicator; 3. The perimeter according to claim 1, wherein the control unit is provided with the LED indicator facing the rear surface of the light receiving body, opposite the light receiving surface.

6. 6. The perimeter according to claim 5, wherein the control unit is configured to be retrofittable to a known perimeter having a conventional light source.

7. further comprising a light meter for measuring the illuminance of the spot light; 6. The perimeter according to claim 5, wherein the LED indicator is configured to convert the illuminance of the light received by the light meter into brightness and display it.

8. It further includes an operation panel, 3. The perimeter according to claim 1, wherein the operation panel is capable of controlling the amount of light supplied to the LED so that the brightness of the spotlight is set to one of 20 levels of brightness: 1x, 0.8x, 0.63x, 0.5x, 0.4x, 0.315x, 0.25x, 0.2x, 0.16x, 0.125x, 0.1x, 0.08x, 0.063x, 0.05x, 0.04x, 0.0315x, 0.025x, 0.02x, 0.016x, or 0.0125x, or a brightness of 0.01x or 0.0001x the brightness of each level.

9. 3. The perimeter according to claim 1, wherein the color temperature of the light from the LED is 2600K to 3300K.

10. a filter disposed immediately above the light path of the LED; The filter reduces the peak irradiance of the LED wavelengths between 435 nm and 455 nm to 55% or less, and has a transmittance of 90% or more for wavelengths between 460 nm and 700 nm. The perimeter according to claim 9, characterized in that

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