Light irradiation device

Abstract

To provide a device capable of easily checking whether or not an optimum range of the retina is irradiated with ultraviolet light.SOLUTION: A light irradiation device 1 includes: a light source device 2 capable of radiating an ultraviolet ray and visible light; and a light guide member 3 made of a material that allows the ultraviolet ray and visible light radiated from the light source device 2 to be propagated inside and allows external light incident from the outside to be transmitted. The light guide member 3 is arranged in proximity of the eyeball at a position for covering the front of the eyeball at least partially, and the ultraviolet ray and visible light propagated inside are caused to be emitted from an emission region 10b of the front of the eyeball, and caused to enter the eyeball. A user can easily check if the light source device is actuated normally by visually recognizing the visual light.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present invention relates to a light irradiation device. [Background technology]

[0002] BACKGROUND ART In the past, a wearable device that irradiates the eyeball with ultraviolet light of 360 nm to 400 nm has been proposed with the aim of suppressing the progression of myopia (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6175210 specification Summary of the Invention [Problem to be solved by the invention]

[0004] The device in Patent Document 1 is an apparatus in which an ultraviolet light source is placed on the rim of the patient's eyeglasses or the brim of a hat, and ultraviolet light emitted from the ultraviolet light source is incident on the eyeball from a corner position that does not obstruct the patient's field of vision. With this device, ultraviolet light is incident from a direction that forms a large angle with the visual axis, making it difficult to irradiate the optimal area of the retina with ultraviolet light. Furthermore, ultraviolet light has a wavelength of 360 nm to 400 nm, which is very difficult to see with the naked eye, making it difficult to confirm whether the optimal area of the retina is being irradiated. Therefore, it is desirable to be able to easily check whether or not ultraviolet light is being irradiated onto the optimal area of the retina. [Means for solving the problem]

[0005] A first aspect of the present disclosure is a light irradiation device comprising a light source device capable of emitting ultraviolet light and visible light, and a light-guiding member made of a material that allows the ultraviolet light and visible light emitted from the light source device to propagate inside and is capable of transmitting external light incident from the outside, wherein the light-guiding member is positioned close to the eyeball in a position that covers at least a portion of the front of the eyeball, and the ultraviolet light and visible light that have propagated inside are emitted from an exit area in front of the eyeball to enter the eyeball.

[0006] According to this aspect, ultraviolet light and visible light emitted from the light source device enter the light-guiding member, at least a portion of which is disposed in a position covering the front of the patient's eyeball, and after propagating through the light-guiding member, are emitted from the front of the eyeball toward the eyeball. This allows ultraviolet light to enter in a direction along the visual axis of the eyeball and irradiate the retina near the central region around the fovea centralis within the eyeball, thereby irradiating ultraviolet light over a wide area of the retina and efficiently suppressing the progression of myopia.

[0007] On the other hand, visible light emitted from the light source device, propagated through the light-guiding member, and then entered the eyeball is irradiated onto the retina in the eyeball and is perceived by the user's vision. That is, by visually perceiving the visible light, the user can easily confirm that the light source device is operating normally. Furthermore, by visually confirming the visible light emitted from the same light source device as the ultraviolet light, passing through the same light-guiding member, and emitted from the emission area in front of the eyeball, the ultraviolet light is also irradiated onto a wide area of the retina, and the user can easily infer that there is nothing abnormal with the light source device or the light-guiding member.

[0008] In the above aspect, the light-guiding member may have the same entrance area through which the ultraviolet light and the visible light emitted from the light source device enter the inside of the light-guiding member, and the ultraviolet light and the visible light that have propagated inside may exit from the same exit area. This allows ultraviolet light and visible light emitted from the same light source device to enter the light-guiding member from the same entrance region, propagate through the light-guiding member, and exit toward the eyeball from the same exit region. In other words, because ultraviolet light and visible light enter the eyeball through the same path, it can be estimated with a high degree of certainty that ultraviolet light is irradiating an appropriate area of the retina through visual perception of visible light.

[0009] In addition, in the above aspect, a diffraction grating may be provided in each of the entrance area and the exit area, and the light source device and each of the diffraction gratings may be positioned so that the shape of the visible light emitted from the light source device can be recognized by the eyeball. The diffraction grating arranged in the entrance region diffracts ultraviolet and visible light incident on the light-guiding member in the appropriate propagation direction within the light-guiding member, allowing the light to be guided without waste. The diffraction grating arranged in the exit region diffracts ultraviolet and visible light propagating through the light-guiding member, allowing the light to be efficiently emitted outside the light-guiding member. Furthermore, because the diffraction grating is formed with minute irregularities, it is possible to prevent refraction of external light passing through the light-guiding member. Therefore, ultraviolet light can be emitted into the eye from the front of the eye with almost no obstruction to the field of view.

[0010] Furthermore, by arranging the light source device and the diffraction grating at a position where the shape of the visible light emitted from the light source device can be recognized by the eyeball, the user can recognize the visible light not only in terms of brightness but also in terms of its shape, which makes it possible to distinguish the visible light emitted from the light source device from external light that passes through the light-guiding member and enters the eyeball, making it easy to check that there are no abnormalities in the light source device or the light-guiding member.

[0011] In the above aspect, the light source device may include an ultraviolet light source that emits light containing ultraviolet rays, and a visible light source that emits the visible light. This allows the light containing ultraviolet light emitted from the ultraviolet light source and the visible light emitted from the visible light source to be emitted toward the light guide member from the same light source device.

[0012] In the above aspect, the ultraviolet light source and the visible light source may be capable of being turned on and off individually. Visible light is necessary when checking whether there are any abnormalities in the light source device and the light guide member, but is unnecessary for suppressing myopia caused by ultraviolet rays, and being perceived visually is bothersome.

[0013] By turning on the ultraviolet light source and turning off the visible light source, it is possible to effectively suppress the progression of myopia without causing any inconvenience. By turning on the visible light source and turning off the ultraviolet light source, it is possible to confirm that there are no abnormalities in the light source device and the light-guiding member without generating ultraviolet rays. Furthermore, by turning on both the ultraviolet light source and the visible light source, it is possible to confirm that there are no abnormalities in the light source device and the light-guiding member while suppressing the progression of myopia caused by ultraviolet rays.

[0014] In the above aspect, the light source device may include a mask disposed between the visible light source and the light-guiding member, and the mask may include a visible light-transmitting portion that transmits the ultraviolet light and the visible light, and a visible light-shielding portion that blocks the visible light and transmits the ultraviolet light. When the light source device is activated, visible light emitted from the visible light source is transmitted through the visible light transmitting portion of the mask and is blocked by the visible light blocking portion, while ultraviolet light emitted from the ultraviolet light source is transmitted through both the visible light transmitting portion and the visible light blocking portion of the mask.

[0015] This allows the visible light transmitted through the visible light transmitting section of the mask and the ultraviolet light transmitted through the entire mask to be incident on the eyeball via the light guiding member. In other words, the user can easily confirm that there is no abnormality in the light guiding member by the visible light transmitted through the visible light transmitting section of the mask, and can also easily infer that there is no abnormality in the light source device.

[0016] In the above aspect, the light source device may include a light pipe disposed between the visible light source and the mask. The visible light emitted from the visible light source is refracted multiple times while propagating through the light pipe, smoothing the intensity distribution. Of the smoothed visible light emitted from the light pipe, only the visible light that passes through the visible light transmitting portion of the mask is imaged on the subject's retina. This allows the subject to visually perceive visible light in the shape of the visible light transmitting portion regardless of the shape of the visible light source, making it easy to confirm that there is nothing abnormal with the light irradiation device.

[0017] In the above aspect, the mask may be fixed to the light guide member. By providing the mask with a visible light transmitting section and a visible light blocking section, ultraviolet light can be irradiated onto the eyeball while the mask is still positioned on the optical path, eliminating the need for a mechanism to move the mask and simplifying the structure.

[0018] In addition, in the above aspect, the light source device may include an ultraviolet light source that emits light containing the ultraviolet rays, and a wavelength conversion member that converts a portion of the ultraviolet rays emitted from the ultraviolet light source into the visible light. This allows the light source device to be operated and light containing ultraviolet rays to be emitted from the ultraviolet light source, thereby suppressing the progression of myopia, and also allows a portion of the ultraviolet rays emitted from the ultraviolet light source to be converted into visible light by the wavelength conversion member.

[0019] The visible light converted from ultraviolet light travels the same path as ultraviolet light, enters the eyeball, and is irradiated onto the retina, allowing the user to visually perceive the visible light. Because the user perceives visible light converted from ultraviolet light, it is possible to confirm that the visible light source and light-guiding member are normal, and it is also easy to confirm that there is no abnormality in the ultraviolet light source.

[0020] In the above aspect, the wavelength conversion member may be provided so as to be insertable into and detachable from a light path extending from the ultraviolet light source toward the light guide member. By removing the wavelength conversion member from the optical path, the progression of myopia can be effectively suppressed without causing any annoyance due to visible light, while by inserting the wavelength conversion member into the optical path, it is possible to check that there are no abnormalities in the light source device and the light guide member while suppressing the progression of myopia caused by ultraviolet light.

[0021] In addition, in the above aspect, the light source device may include a mask disposed between the wavelength conversion member and the light-guiding member, and the mask may include a visible light transmitting portion that transmits the ultraviolet light and the visible light, and a visible light blocking portion that blocks the visible light and transmits the ultraviolet light. When the light source device is operated, part of the ultraviolet light emitted from the ultraviolet light source is converted into visible light by the wavelength conversion member. The visible light is transmitted through the visible light transmitting portion of the mask and is blocked by the visible light blocking portion. The ultraviolet light emitted from the ultraviolet light source is also transmitted through the entire visible light transmitting portion and the visible light blocking portion of the mask.

[0022] This allows the visible light transmitted through the visible light transmitting section of the mask and the ultraviolet light transmitted through the entire mask to be incident on the eyeball via the light guiding member, which means that the user can easily confirm that there are no abnormalities in the light source device and the light guiding member by the visible light transmitted through the visible light transmitting section of the mask.

[0023] In the above aspect, the light source device may include a light pipe disposed between the wavelength conversion member and the mask. The ultraviolet light emitted from the ultraviolet light source and the visible light obtained by converting a portion of the ultraviolet light using a wavelength conversion member are refracted multiple times while propagating through the light pipe, smoothing their intensity distribution. Of the smoothed visible light emitted from the light pipe, only the visible light that passes through the visible light transmitting portion of the mask is focused on the subject's retina. This allows the visible light of the shape of the visible light transmitting portion to be perceived visually, regardless of the shape of the visible light conversion member, making it easy to confirm that there is no abnormality in the light irradiation device. Furthermore, the remaining ultraviolet light that is not converted into visible light can be irradiated onto the subject's retina with its intensity distribution smoothed by the light pipe.

[0024] In addition, in the above aspect, the ultraviolet light emitted from the light source device may have an emission peak at a wavelength of 360 nm to 400 nm, and the visible light emitted from the light source device may have an emission peak at a wavelength of 400 nm to 700 nm. [Brief explanation of the drawings]

[0025] [Figure 1A] 1 is a front view showing a light irradiation device according to a first embodiment of the present invention. [Figure 1B] FIG. 1B is a plan view showing the light irradiation device of FIG. 1A. [Figure 2] 1B is a schematic vertical cross-sectional view illustrating the principle of the light irradiation device of FIG. 1A. [Figure 3] 1B is a diagram showing an example of an ultraviolet light source and a visible light source of the light irradiation device of FIG. 1A. [Figure 4] 1B is a diagram showing an example of an image of a visible light source within the field of view of the light irradiation device of FIG. 1A. FIG. [Figure 5] 1B is a diagram showing another example of an image of a visible light source within the field of view of the light irradiation device of FIG. 1A. FIG. [Figure 6] 1B is a diagram showing another example of an image of a visible light source within the field of view of the light irradiation device of FIG. 1A. FIG. [Figure 7] 1B is a diagram showing another example of an image of a visible light source within the field of view of the light irradiation device of FIG. 1A. FIG. [Figure 8]1B is a diagram showing another example of an image of a visible light source within the field of view of the light irradiation device of FIG. 1A. FIG. [Figure 9] FIG. 4 is a schematic vertical cross-sectional view showing a light irradiation device according to a second embodiment of the present invention. [Figure 10] 10 is a perspective view showing an example of a mask of the light irradiation device of FIG. 9. FIG. [Figure 11] 11 is a graph showing an example of the transmittance characteristics of a multilayer film applied to the mask of FIG. 10. [Figure 12] 10 is a schematic vertical cross-sectional view showing a modified example of the light irradiation device of FIG. [Figure 13] FIG. 10 is a schematic vertical cross-sectional view showing a light irradiation device according to a third embodiment of the present invention. [Figure 14] 14 is a perspective view showing an example of a wavelength conversion member of the light irradiation device of FIG. [Figure 15] FIG. 14 is a schematic vertical cross-sectional view showing a modified example of the light irradiation device of FIG. [Figure 16] 14 is a schematic vertical cross-sectional view showing another modified example of the light irradiation device of FIG. [Figure 17] FIG. 1B is a schematic vertical cross-sectional view showing a modified example of the light irradiation device of FIG. 1A. DETAILED DESCRIPTION OF THE INVENTION

[0026] A light irradiation device 1 according to an embodiment of the present disclosure will be described below with reference to the drawings. As shown in FIGS. 1A and 1B, the light irradiation device 1 according to this embodiment is an eyeglass-type device worn by a subject who wishes to suppress the progression of myopia, and includes a light source device 2 and a light-guiding member 3.

[0027] The light source device 2 and the light guide member 3 are attached to a spectacle frame 4. The eyeglass frame 4 includes a pair of temples 5 that are worn by the subject on both ears, and a rim 6 to which one end of each temple 5 is connected.

[0028] The light source devices 2 are arranged, for example, at the inner positions of a pair of temples 5 of the eyeglass frame 4, respectively. As shown in FIG. 2, the light source device 2 includes an ultraviolet light source 7 that emits light including ultraviolet rays, a visible light source 8 that emits visible light, and a lens 9 that collimates the light emitted from the ultraviolet light source 7 and the visible light source 8.

[0029] The ultraviolet light source 7 is an LD, LED, or the like having an emission peak in the wavelength range of 360 nm to 400 nm. The visible light source 8 is an LD, LED, or the like having an emission peak in the wavelength range of 400 nm to 700 nm. The ultraviolet light source 7 and the visible light source 8 are arranged on the same plane, for example, as shown in FIG. 3. In the example shown in FIG. 3, the visible light source 8 is arranged in a cross shape, one row at a time, at the center of the vertical and horizontal directions of the square array of the ultraviolet light sources 7. In the figure, the visible light source 8 is indicated by hatching.

[0030] The light source device 2 is provided with a switch (not shown), and by operating the switch, the ultraviolet light source 7 and the visible light source 8 can be individually switched on / off. The lens 9 is, for example, a collimating lens, which converts the light emitted from the ultraviolet light source 7 and the visible light source 8 into approximately parallel light and makes the parallel light incident on the light-guiding member 3. For example, the ultraviolet light source 7 and the visible light source 8 are disposed at the focal position of the lens 9.

[0031] The light source device 2 is arranged with its radiation end 2a facing the edge of the light-guiding member 3 close to the rim 6, and emits light containing ultraviolet light and visible light that has become approximately parallel toward the opposing light-guiding member 3.

[0032] The light-guiding member 3 is a plate-like member placed on the rim 6 of the eyeglass frame 4 at a position where a pair of eyeglass lenses would be placed in normal eyeglasses, and is made of a material with a refractive index of 1.8 or less, such as COP, acrylic resin, cycloolefin copolymer (COC), polystyrene, BK7, i-line glass, LF5, FK5, or fluorite. This allows the light-guiding member 3 to transmit light including ultraviolet light with a wavelength of 360 nm or more and 400 nm or less and visible light inside, and also allows external light, which is visible light from outside the light irradiation device 1, to pass through in the plate thickness direction.

[0033] The light-guiding member 3 also has diffraction gratings 11 and 12 in an entrance region 10a where light emitted from the ultraviolet light source 7 is incident, and in an exit region 10b that is located in front of the eyeball A of the subject when the light irradiation device 1 is worn. The diffraction grating (hereinafter also referred to as input grating) 11 provided in the entrance region 10a diffracts the light from the light source device 2 located outside the light-guiding member 3 when it enters the light-guiding member 3. The input grating 11 has the function of directing the light to propagate by total reflection inside the light-guiding member 3 in a direction approaching the exit region 10b.

[0034] The diffraction grating (hereinafter also referred to as output grating) 12 provided in the emission region 10b has the function of diffracting the light propagated inside the light-guiding member 3 and emitting it to the outside of the light-guiding member 3.

[0035] The operation of the light irradiation device 1 according to this embodiment configured as above will be described below. A subject who wishes to suppress the progression of myopia places the temples 5 of the eyeglass frame 4 over both ears and the rims 6 of the eyeglass frame 4 in front of the eyes. This allows the subject to wear the light irradiation device 1 with the pair of light guiding members 3 held by the rims 6 of the eyeglass frame 4 positioned close to the eyeballs A in positions where at least a portion of each light guiding member 3 covers the front of each of the left and right eyeballs A. In this state, the emission region 10b of the light guiding member 3 is positioned in front of both eyeballs A of the subject.

[0036] In this case, the light-guiding member 3 is made of a material that can transmit visible light, so even if it covers the front of the eyeball A, it does not obstruct external light, which is visible light from the outside world, but allows the light to pass through in the thickness direction and enter the eyeball A. This allows the subject to see the outside world while wearing the light irradiation device 1, and to carry out daily life without any inconvenience.

[0037] In this state, if the subject wishes to achieve the effect of suppressing the progression of myopia, he or she operates a switch to activate the ultraviolet light source 7 provided in the light source device 2, causing the ultraviolet light source 7 to emit light containing ultraviolet light. The light emitted from the ultraviolet light source 7 is converted into parallel light by a lens 9 and then enters the light-guiding member 3 disposed opposite the radiation end 2a of the light source device 2. An input grating 11 is provided in an entrance region 10a opposite the radiation end 2a of the light source device 2, and the light emitted from the radiation end 2a is diffracted by the input grating 11 when it enters the light-guiding member 3.

[0038] 2, the light diffracted by input grating 11 is directed in a direction of total reflection inside light-guiding member 3. As a result, the light entering light-guiding member 3 is propagated while repeatedly being totally reflected inside light-guiding member 3, and when it reaches output grating 12 provided in a region near the center of light-guiding member 3, it is diffracted and emitted to the outside of light-guiding member 3.

[0039] Furthermore, the output grating 12 is provided in the exit region 10b, which is located in front of the eyeball A, on the surface of the light-guiding member 3 facing the eyeball A, so that the light emitted from the light-guiding member 3 enters the eyeball A at a small angle with respect to the visual axis. This makes it easier for ultraviolet light to enter in a direction along the visual axis of the eyeball A, and can irradiate the retina near the central region around the fovea centralis in the eyeball A. As a result, compared to conventional methods in which ultraviolet light is incident from a direction that makes a large angle with respect to the visual axis, it is possible to irradiate ultraviolet light over a wider area of the retina, thereby achieving the effect of efficiently suppressing the progression of myopia.

[0040] Furthermore, because the output grating 12 is formed by minute concaves and convexes, it is possible to prevent refraction of external light, which is visible light that passes through the light-guiding member 3 in the thickness direction. This has the advantage that ultraviolet light can be emitted into the eyeball A from the front of the eyeball A without interfering with the field of view much.

[0041] Next, when it is desired to check whether the light irradiation device is irradiating the optimal area of the retina with ultraviolet light, the visible light source 8 provided in the light source device 2 is activated by operating a switch, causing the visible light source 8 to emit visible light. The visible light emitted from the visible light source 8 also follows the same optical path as the ultraviolet light. That is, after being converted into parallel light by the lens 9, the light enters the light-guiding member 3 from the entrance region 10a thereof, propagates through the light-guiding member 3 by total reflection, exits the light-guiding member 3 from the exit region 10b, and enters the eyeball A from the front of the eyeball A. The visible light incident on the eyeball A is focused as an image of the visible light source 8 on the retina near the central region around the fovea.

[0042] This allows the subject to visually perceive the visible light emitted from the visible light source 8. Because the ultraviolet light and visible light emitted from the light source device 2 follow the same path to be irradiated onto the retina in the eyeball A, the subject's perception of the visible light allows the subject to confirm that there are no abnormalities in the visible light source 8 and the light-guiding member 3 and that they are arranged in the correct positions. Furthermore, with the light irradiation device 1 according to this embodiment, the subject's visual perception of visible light allows the subject to infer that there are no abnormalities in the ultraviolet light source 7, which is arranged in the same positional relationship as the visible light source 8, and that ultraviolet light is being irradiated onto the appropriate range of the retina.

[0043] In this case, according to the present embodiment, the visible light sources 8 are arranged in a row in a cross shape, and therefore the subject can visually perceive the visible light emitted from the visible light sources 8 as a cross-shaped image of the visible light source 8. By using such an image of the visible light source 8 having a shape that can be recognized by the eyeball A, the visible light emitted from the visible light source 8 can be perceived as clearly distinguished from external light, which is visible light that passes through the light-guiding member 3. In other words, there is an advantage that the subject can check whether there is an abnormality in the light irradiation device 1 while looking at the outside world while wearing the light irradiation device 1.

[0044] 4 and 5, with the image 8A of the visible light source devices 8 arranged in a cross shape, the state of the light source device 2 or the light-guiding member 3 can also be confirmed by the intersection position of the cross. In FIGS. 4 and 5, the subject's field of view F is shown by a rectangle. As shown in FIG. 4, if the crosses appear to intersect in the center of the field of view, there is no abnormality in the light source device 2 or the light-guiding member 3. However, if the crosses appear to intersect in a position shifted from the center of the field of view, as shown in FIG. 5, it can be confirmed that there is an abnormality in the light source device 2 or the light-guiding member 3.

[0045] Furthermore, according to this embodiment, the ultraviolet light source 7 and the visible light source 8 can be switched on / off independently, so that only the visible light source 8 can be turned off when there is no need to check for abnormalities in the light irradiation device 1. This prevents the subject from perceiving the image of the visible light source 8 as overlapping with external light from the outside world, and enables the progression of myopia to be inhibited without any annoyance.

[0046] In this embodiment, the visible light sources 8 are arranged in a cross shape, one row per row, among the square array of ultraviolet light sources 7. However, the visible light sources 8 may be arranged in any other shape. However, it is preferable that the visible light sources 8 are arranged in a shape that can be recognized by the subject, such as a cross, a simple shape such as a circle, a polygon, or a ring, or a shape that can be recognized by the subject, such as a letter, a symbol, a logo, or a character. This is because a random arrangement may cause the image 8A of the visible light source 8 to blend in with external light, making it difficult for the subject to visually perceive it.

[0047] Furthermore, it is preferable that the visible light sources 8 be arranged in a cross-like pattern as described above, so that it is easy to determine the presence or absence of an abnormality in the light source device 2 or the light-guiding member 3 based on the position of the visible light image 8A. If it is not necessary to use the position of the visible light image 8A, the visible light sources 8 may be arranged so that the visible light image 8A is formed as a mark in a shape that is easily recognizable by the subject, such as a circle, polygon, or logo mark, somewhere on the periphery of the field of view F, as shown in Fig. 6, for example. Furthermore, it is even more preferable if the visible light image 8A is arranged in a form that does not cross the center of the field of view F, such as a ring as shown in Figure 7 or an arrow as shown in Figure 8, because this reduces the area that is not irradiated with ultraviolet light by the visible light source 8 and increases the effect of suppressing the progression of myopia.

[0048] Furthermore, although the ultraviolet light source 7 and the visible light source 8 are arranged on the same plane at the focal position of the lens 9, they may alternatively be arranged shifted either forward or backward in the optical axis direction relative to the focal position of the lens 9. By shifting the ultraviolet light source 7 from the focal position of the lens 9 in the optical axis direction, the image of the ultraviolet light source 7 is prevented from being formed on the subject's retina (defocused), thereby smoothing the intensity distribution of the ultraviolet light irradiated onto the retina. Furthermore, with regard to visible light, even if the visible light source 8 is slightly shifted from the focal position of the lens 9 in the optical axis direction, the image of the visible light source 8 can be captured by the autofocus function of the eyeball A.

[0049] Furthermore, if the visible light source 8 is arranged in a manner that does not cross the center, it is highly likely that it will not interfere with the field of view F even if it is always on, so it is not necessary to be able to turn the visible light source 8 on / off separately from the ultraviolet light source 7. The visible light emitted from the visible light source 8 is exemplified as light having an emission peak at wavelengths of 400 nm to 700 nm. Therefore, the color of the visible light may be any color from purple to red, but it is preferable that the color be a color that stands out against the background external light, such as green, yellow, or orange. The visible light may be visible light that includes light in a wide wavelength range, or may be white light that includes all colors.

[0050] Next, a light irradiation device 20 according to a second embodiment of the present disclosure will be described below with reference to Fig. 9. In the description of this embodiment, parts that share the same configuration as the light irradiation device 1 according to the first embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0051] The light irradiation device 20 according to this embodiment differs from the light irradiation device 1 according to the first embodiment in that a light source device 21 includes a mask 22 between the ultraviolet light source 7 and visible light source 8 and the lens 9. The mask 22 is a flat plate member disposed at a position that separates the ultraviolet light source 7 and visible light source 8 from the lens 9, and includes a visible light transmitting portion 22a that transmits ultraviolet light and visible light, and a visible light blocking portion 22b that blocks visible light and transmits ultraviolet light, as shown in Fig. 10 .

[0052] In the mask 22, a multilayer film having transmittance characteristics as shown in Fig. 11 is formed on almost the entire surface of a substrate 22c such as glass that is capable of transmitting light of all wavelengths, to form visible light blocking portions 22b, and portions on which the multilayer film is not formed are made into visible light transmitting portions 22a. In this embodiment, the visible light transmitting portions 22a are slits having a cross shape.

[0053] In the first embodiment, the ultraviolet light source 7 and the visible light source 8 are disposed at the focal position of the lens 9, but in the present embodiment, the mask 22 is disposed at the focal position of the lens 9. Therefore, the ultraviolet light source 7 and the visible light source 8 are disposed at positions slightly shifted from the focal position of the lens 9 in the optical axis direction. In this embodiment, the ultraviolet light source 7 and the visible light source 8 may be arranged in any manner.

[0054] According to the light irradiation device 20 of this embodiment, both the visible light transmitting portion 22a and the visible light blocking portion 22b of the mask 22 have transmittance characteristics that allow ultraviolet light to pass through, and therefore the ultraviolet light emitted from the ultraviolet light source 7 is not blocked by the mask 22. Therefore, almost all of the ultraviolet light emitted from the ultraviolet light source 7 is collimated by the lens 9, propagates through the light-guiding member 3, enters the eyeball A of the subject, and is irradiated onto the retina near the fovea.

[0055] On the other hand, the visible light emitted from the visible light source 8 can pass only through the visible light transmitting portion 22a of the mask 22, and follows the same path as the ultraviolet light to be irradiated onto the retina of the subject's eyeball A. By placing the mask 22 at the focal position of the lens 9, an image of the visible light transmitting portion 22a of the mask 22 is formed on the subject's retina, and the subject can visually recognize the shape of the image of the visible light transmitting portion 22a, thereby confirming that there is no abnormality in the light irradiation device 1.

[0056] According to this embodiment, the shape of the visible light that is imaged on the retina is determined by the visible light transmitting portion 22a of the mask 22, so there is no need to determine the shape of the visible light by the arrangement of the visible light source 8. This has the advantage of making it easier to form a shape of visible light that is recognizable to the user. Furthermore, because the ultraviolet light source 7 is positioned at a position offset in the optical axis direction from the focal position of the lens 9, the intensity distribution of the ultraviolet light irradiated onto the retina is smoothed. Therefore, even if the visible light source 8 is positioned among the arrangement of the ultraviolet light sources 7, it is possible to eliminate areas on the retina that are not partially irradiated with ultraviolet light.

[0057] In this embodiment, as shown in FIG. 12, a light pipe 23 may be disposed between the ultraviolet light source 7 and the visible light source 8 and the mask 22. The light pipe 23 is a columnar optical member that mixes multiple types of light incident on one end 23a and emits the mixed light from the other end 23b. In the example shown in FIG. 12, the ultraviolet light source 7 and the visible light source 8 are provided separately, and a condenser lens 24 and a half mirror or dichroic mirror 25 are disposed between them. The light containing ultraviolet light emitted from the ultraviolet light source 7 and the visible light emitted from the visible light source 8 are combined by the half mirror or dichroic mirror 25 and then enter the incident end 23a of the light pipe 23.

[0058] By disposing the light pipe 23, ultraviolet light and visible light incident on the input end 23a are mixed while propagating through the light pipe 23 and are emitted from the output end 23b. Because the ultraviolet light is refracted multiple times inside the light pipe 23, the intensity distribution is smoothed, and regardless of the form of the ultraviolet light source 7, ultraviolet light with a smooth intensity distribution can be irradiated onto the subject's retina.

[0059] Furthermore, visible light propagating within light pipe 23 is also refracted multiple times within light pipe 23, and is emitted from exit end 23b with a smoothed intensity distribution. Of the visible light emitted from light pipe 23, only the visible light that has passed through visible light transmitting section 22a of mask 22 is imaged on the subject's retina. As a result, regardless of the shape of visible light source 8, visible light in the shape of visible light transmitting section 22a is visually perceived, making it easy to confirm that there is no abnormality in light irradiation device 20.

[0060] In the present embodiment, the mask 22 may be fixed to the light-guiding member 3. This allows the eye A to be irradiated with ultraviolet light while the mask 22 remains positioned on the optical path, eliminating the need for a mechanism to move the mask 22 and simplifying the structure.

[0061] Next, a light irradiation device 30 according to a third embodiment of the present disclosure will be described below with reference to the drawings. In the description of this embodiment, parts having the same configuration as the light irradiation device 20 according to the second embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0062] 13, in a light irradiation device 30 according to this embodiment, a light source device 31 does not include a visible light source 8. Furthermore, the light source device 31 includes a wavelength conversion member 32, instead of the mask 22, at the position of the mask 22 shown in FIG. 9, which is removably insertable in a direction (indicated by arrow B) intersecting the optical axis. 14, the wavelength conversion member 32 is formed by applying a fluorescent material 32b to a substrate 32a such as glass that is capable of transmitting light of almost all wavelengths, in the same shape as the visible light transmitting portion 22a of the mask 22 in the second embodiment. Any material that is excited by ultraviolet light and emits visible light can be used as the fluorescent material 32b.

[0063] When the wavelength conversion member 32 is removed from the optical path of the ultraviolet light source 7, all of the ultraviolet light emitted from the ultraviolet light source 7 passes through the lens 9 and the light-guiding member 3 and is irradiated onto the retina in the subject's eyeball A. On the other hand, when the wavelength conversion member 32 is inserted into the optical path of the ultraviolet light source 7, the ultraviolet light emitted from the ultraviolet light source 7 that passes through the fluorescent material 32b of the wavelength conversion member 32 is converted into visible light, and the other ultraviolet light passes through the wavelength conversion member 32 as is.

[0064] As a result, while ultraviolet light is irradiated onto the subject's retina, a visible light image having a shape formed by the shape of the fluorescent material 32b can be formed on the retina, and the visible light image can be perceived visually, making it easy to confirm that there is no abnormality in the light irradiation device 30. According to the light irradiation device 30 of this embodiment, ultraviolet light emitted from the ultraviolet light source 7 is converted into visible light, and therefore, there is an advantage that if the subject can visually perceive the visible light image having a predetermined shape, it can easily be confirmed that there is no abnormality in the ultraviolet light source 7.

[0065] Since the wavelength conversion member 32 is provided detachably, if visible light becomes an obstacle during ultraviolet irradiation, the wavelength conversion member 32 can be retracted to the outside of the optical path. By placing the wavelength conversion member 32 on the optical path as needed during ultraviolet irradiation, it is possible to check each time whether ultraviolet light is being properly irradiated onto the retina.

[0066] In this embodiment, a wavelength conversion member 32 is removably arranged in place of the mask 22 in the second embodiment, but the wavelength conversion member 32 may be removably arranged between the mask 22 and the ultraviolet light source 7 as shown in Fig. 15. In this case, the mask 22 may be the same as the mask 22 shown in Fig. 10, and is preferably arranged at the focal position of the lens 9.

[0067] Alternatively, the wavelength conversion member 32 may be a fluorescent plate in which the fluorescent material 32b is applied in any form to the substrate 32a made of glass. The visible light converted by the ultraviolet light passing through the wavelength conversion member 32 passes only through the visible light transmitting portion 22a of the mask 22, and therefore the fluorescent material 32b in the wavelength conversion member 32 may be applied to the entire substrate 32a or to a part of the substrate 32a. 16, a light source device 31 may include a mask 22 and a light pipe 23, similar to that shown in FIG. 12, and a wavelength conversion member 32 may be removably disposed between the ultraviolet light source 7 and the light pipe 23.

[0068] 6 to 8, wavelength conversion member 32 may be always disposed on the optical path of ultraviolet light source 7, as long as it is coated with fluorescent material 32b in a pattern that allows visible light image 8A to be formed around field of view F. This eliminates the need to provide a mechanism for inserting and removing wavelength conversion member 32, and allows for the miniaturization of light irradiation device 30.

[0069] Furthermore, instead of an LD, an LED, or the like, a display such as LCOS (trademark), OLED, or DLP (trademark) may be used as the visible light source 8. In this case, as shown in FIG. 17 , light including ultraviolet light from the ultraviolet light source 7 and visible light from the visible light source 8 consisting of a display may be multiplexed using a half mirror or dichroic mirror 25. By using a display as the visible light source 8, it is possible to form an image of visible light of any shape and color on the retina, and the visible light can be turned on and off by turning the image display on and off, which has the advantage of eliminating the need for an insert / removal mechanism.

[0070] Furthermore, in the present embodiment, the light source device 2 and the light guiding member 3 are attached to the eyeglass frame 4 having a pair of temples 5 and a rim 6, but the present invention is not limited to this. For example, the light irradiation devices 1, 20, 30 may have any shape, such as an eyeglass frame 4 without a rim 6 or an eyeglass-type device without temples 5 and a rim 6.

[0071] Also, the example has been given in which ultraviolet light and visible light emitted from the light source device 2 are directly incident on the light-guiding member 3. Alternatively, the light source devices 2, 21, 31 may be disposed on the proximal end side of the temple 5, and the light may be guided to a position close to the light-guiding member 3 by an optical fiber or light guide (not shown). By disposing the light source devices 2, 21, 31, which have mass, near the ears of the subject, the light-guiding member 3 side can be prevented from becoming heavy, improving wearability.

[0072] In this embodiment, the ultraviolet light and visible light propagating inside the light-guiding member 3 are emitted from the light-guiding member 3 by the diffraction grating 12 provided in the light-guiding member 3. Alternatively, a structure other than the diffraction grating 12, for example, minute irregularities having random pitches and heights formed by roughening the surface of the light-guiding member 3, may be employed.

[0073] In addition, in this embodiment, light including ultraviolet and visible light is made to enter the light-guiding member 3 by the input grating 11 provided at a position close to the edge of the light-guiding member 3, but instead, ultraviolet and visible light may be made to enter from the edge of the light-guiding member 3. [Explanation of symbols]

[0074] 1,20,30 Light irradiation device 2,21,31 Light source device 3 Light guide member 7 UV light source 8 Visible light source 10a incident area 10b Output area 11 Diffraction grating (input grating) 12 Diffraction grating (output grating) 22 Mask 22a Visible light transmitting part 22b Visible light shielding part 23 Light Pipe 32 Wavelength conversion material A eyeball

Claims

1. a light source device capable of emitting ultraviolet light and visible light; a light guide member made of a material that allows the ultraviolet light and the visible light emitted from the light source device to propagate therein and that is capable of transmitting external light incident from the outside, The light-guiding member is positioned close to the eyeball in a position where at least a portion of it covers the front of the eyeball, and the ultraviolet light and visible light that have propagated inside are emitted from an exit area in front of the eyeball and made to enter the eyeball.

2. 2. The light irradiation device according to claim 1, wherein the light guide member has a same entrance area through which the ultraviolet light and the visible light emitted from the light source device enter the inside of the light guide member, and the ultraviolet light and the visible light propagated inside the light guide member are emitted from the same exit area.

3. The incident area and the exit area each include a diffraction grating; The light irradiation device according to claim 2 , wherein the light source device and each of the diffraction gratings are disposed at a position where the shape of the visible light emitted from the light source device can be recognized by the eyeball.

4. The light irradiation device according to claim 1 , wherein the light source device comprises an ultraviolet light source that emits light containing the ultraviolet light, and a visible light source that emits the visible light.

5. 5. The light irradiation device according to claim 4, wherein the ultraviolet light source and the visible light source can be turned on and off individually.

6. the light source device includes a mask disposed between the visible light source and the light guiding member, 5. The light irradiation device according to claim 4, wherein the mask comprises a visible light transmitting portion that transmits the ultraviolet light and the visible light, and a visible light blocking portion that blocks the visible light and transmits the ultraviolet light.

7. 7. The light irradiation device according to claim 6, wherein the light source device comprises a light pipe disposed between the visible light source and the mask.

8. The light irradiation device according to claim 6 , wherein the mask is fixed to the light guide member.

9. 4. The light irradiation device according to claim 1, wherein the light source device comprises: an ultraviolet light source that emits light containing the ultraviolet rays; and a wavelength conversion member that converts a portion of the ultraviolet rays emitted from the ultraviolet light source into the visible light.

10. The light irradiation device according to claim 9 , wherein the wavelength conversion member is removably provided in a light path extending from the ultraviolet light source to the light guide member.

11. the light source device includes a mask disposed between the wavelength conversion member and the light guiding member, 10. The light irradiation device according to claim 9, wherein the mask comprises a visible light transmitting portion that transmits the ultraviolet light and the visible light, and a visible light blocking portion that blocks the visible light and transmits the ultraviolet light.

12. The light irradiation device according to claim 11 , wherein the light source device comprises a light pipe disposed between the wavelength conversion member and the mask.

13. the ultraviolet light emitted from the light source device has an emission peak in a wavelength range of 360 nm to 400 nm, The light irradiation device according to claim 1 , wherein the visible light emitted from the light source device has an emission peak in the wavelength range of 400 nm to 700 nm.

Images