Illumination device

Abstract

Provided is a lighting device capable of illuminating an object from various directions. This lighting device is provided with: a lighting source; and a light guiding part that has permeability with respect to visible light and that guides light emitted from the light source. The light guiding part is provided with: a cylindrical member; a light extraction part for causing the light, which is guided so as to pass through the inside of a wall part of the cylindrical member, to be emitted from the inside of the wall part. The cylindrical member is provided with: a light entering end surface which is provided to either one of the bottom part or the top part of the cylindrical member so as to face the light source, and through which the light enters the inside of the wall part; and a light emitting part which is included in the inner surface, of the cylindrical member, intersecting with the light entering end surface, and through which the light is emitted from the inside of the wall part.

Description

Technical Field

[0001] The present invention relates to a lighting device.

Background Art

[0002] Conventionally, lighting devices for illuminating objects such as products or exhibits in a showcase have been known.

[0003] As such a lighting device, a configuration having a light guide body having at least one light incident surface facing a light source and a light emitting surface substantially orthogonal thereto, and a prism sheet disposed on the light emitting surface of the light guide body is disclosed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the configuration of Patent Document 1, there is room for improvement in illuminating an object from various directions.

[0006] An object of the present invention is to provide a lighting device capable of illuminating an object from various directions.

Means for Solving the Problems

[0007] In order to solve the above problems, the lighting device of the present invention includes a light source and a light guide unit that is transparent to visible light and guides the light emitted by the light source. The light guide unit includes a cylindrical member and a light extraction unit that emits the light guided through the inside of the wall portion of the cylindrical member from the inside of the wall portion. The cylindrical member is provided at either the bottom or the top of the cylindrical member facing the light source, and includes a light incident end face where the light enters the inside of the wall portion and a light emitting portion that is included in the inner side surface of the cylindrical member intersecting the light incident end face and from which the light exits the inside of the wall portion. The light emitted from inside the wall portion of the cylindrical member illuminates the space inside the cylindrical member. .

[0008] Alternatively, the lighting device of the present invention includes a light source and a light guide unit that is transparent to visible light and guides the light emitted by the light source. The light guide unit includes a curved surface member that is a part of a hollow sphere or an ellipsoid of revolution and a light extraction unit that emits the light guided through the inside of the wall portion of the curved surface member from the inside of the wall portion. The curved surface member is provided at the bottom of the curved surface member facing the light source, and includes a light incident end face where the light enters the inside of the wall portion and a light emitting portion that is included in the inner side surface of the curved surface member intersecting the light incident end face and from which the light exits the inside of the wall portion. The light emitted from inside the wall portion of the curved surface member illuminates the space inside the curved surface member. .

Advantages of the Invention

[0009] According to the present invention, a lighting device capable of illuminating an object from various directions can be provided.

Brief Description of the Drawings

[0010]

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Mode for Carrying Out the Invention

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate. The following embodiments illustrate a lighting device for embodying the technical idea of the present invention, and the present invention is not limited to the following embodiments. The dimensions, materials, shapes, relative arrangements, etc. of the components described below are not intended to limit the scope of the present invention only to those, but are intended to be illustrative unless otherwise specified. Also, the sizes and positional relationships of the members shown in the drawings may be exaggerated for clarity of explanation.

[0012] The lighting device according to the embodiment includes a light source and a light guide unit that guides the light emitted from the light source. The light guide unit includes either a cylindrical member or a curved surface member that is a part of a hollow sphere or an ellipsoid of revolution, and a light extraction unit that emits the light guided through the inside of the wall portion of either the cylindrical member or the curved surface member from the inside of the wall portion.

[0013] Here, the cylindrical member means a cylindrical member. The cylindrical member is not limited to a cylindrical body that is continuous as a whole in the circumferential direction or the like, and also includes a cylindrical member in which the ends of a plate-like member are not connected to the other end, or a cylindrical member in which a part of the circumferential direction or the like is missing. The cylindrical member includes a cylindrical member having a circular or elliptical cross section orthogonal to the axial direction, and a rectangular tube-shaped member having a polygonal cross section orthogonal to the axial direction of the cylindrical member.

[0014] Further, the cylindrical member is provided at either the bottom or the top of the cylindrical member facing the light source, and includes a light incident end face through which light enters the inside of the wall portion and an inner side face of the cylindrical member intersecting the light incident end face, and a light emission portion through which light is emitted from the inside of the wall portion.

[0015] The light emitted by the light source enters the inside of the wall portion in the cylindrical member through the light incident end face, and is guided inside the wall portion. A part of the guided light is reflected, scattered, refracted or diffracted by the light extraction portion toward the inside of the cylindrical member, and exits from the inside of the wall portion of the cylindrical member to the outside through the light emitting portion included in the inner surface of the cylindrical member. The lighting device can illuminate the inside of the lighting device with the light emitted from the light emitting portion.

[0016] Further, the curved surface member is provided at the bottom of the curved surface member facing the light source, and includes a light incident end face through which light enters the inside of the wall portion, and a light emitting portion included in the inner surface of the curved surface member that intersects the light incident end face and through which light exits from the inside of the wall portion.

[0017] The light emitted by the light source enters the inside of the wall portion in the curved surface member through the light incident end face, and is guided inside the wall portion. A part of the guided light is reflected, scattered, refracted or diffracted by the light extraction portion toward the inside of the curved surface member, and exits from the inside of the wall portion of the curved surface member to the outside through the light emitting portion included in the inner surface of the curved surface member. The lighting device can illuminate the inside of the lighting device with the light emitted from the light emitting portion.

[0018] The use, installation location, and illumination object of the lighting device according to the embodiment are not particularly limited. For example, it can be installed on a desk, table or shelf, indoor or outdoor floor surface, etc., and used as a lighting device for illuminating objects such as products or exhibits arranged inside the lighting device as a showcase.

[0019] Hereinafter, various embodiments and modifications of the lighting device having a cylindrical member and the lighting device having a curved surface member will be described. Hereinafter, for convenience of explanation, when the lighting device 100 is viewed from the front side, the lateral direction is defined as the X-axis direction, the depth direction is defined as the Y-axis direction, and the height direction is defined as the Z-axis direction. However, the X-axis direction, Y-axis direction, and Z-axis direction do not limit the orientation of the lighting device 100, and the orientation of the lighting device 100 may be any direction.

[0020] [First Embodiment] [Configuration Example of Lighting Device 100] First, with reference to FIGS. 1, 2A, and 2B, the configuration of the lighting device 100 according to the first embodiment will be described. FIG. 1 is a perspective view for explaining an example of the configuration of the lighting device 100. FIGS. 2A and 2B are views for explaining an example of the configuration of the lighting device 100, where FIG. 2A is a top view and FIG. 2B is a cross-sectional view taken along the line A-A' in (a). Note that the top view in FIG. 2A is a view of the lighting device 100 as seen from the positive Z-axis direction side.

[0021] As shown in FIGS. 1, 2A, and 2B, the lighting device 100 includes a base portion 3, a light source 1, and a light guide portion 300. The light guide portion 300 has a cylindrical member 2.

[0022] The base portion 3 is composed of a material such as resin, metal, or wood, and is a plate-like member that fixes the light source 1 and the cylindrical member 2 in the light guide portion 300. The base portion 3 fixes the cylindrical member 2 that abuts on the flat surface portion of the base portion 3 with an adhesive or the like. A substantially circular groove portion 31 is formed in the flat surface portion of the base portion 3, and the base portion 3 fixes the light source 1 at the bottom surface of this groove portion 31. Further, the base portion 3 includes wiring on which various electrical elements such as LEDs (Light Emitting Diodes) can be mounted.

[0023] The light source 1 includes a plurality of LEDs 11. The plurality of LEDs 11 are arranged along the groove portion 31 so as to draw a substantially circular shape, and each is fixed on the bottom surface of the groove portion 31.

[0024] Each of the plurality of LEDs 11 is electrically connected to the drive circuit 12 via the wiring provided on the base portion 3, and emits light when a drive voltage is applied from the drive circuit 12. The light source 1 can emit an annular light formed by the light emitted from the plurality of LEDs 11.

[0025] The light emitted from the light source 1 may be white light or monochromatic light. Also, among white lights, various colors such as incandescent color, noon white, and daylight color can be selected. However, the configuration of the light source 1 is not limited to one including the LED 11. For example, the light source 1 may include a fluorescent lamp or a cold cathode tube formed in a substantially annular shape, or may include a plurality of optical fibers bundled so that the emission end draws a substantially circular shape.

[0026] The drive circuit 12 is supplied with a power supply voltage from a battery composed of various secondary batteries (for example, lithium-ion batteries, lithium polymer batteries, etc.) or a commercial power supply, and applies a drive voltage of the LED 11 to the light source 1. Note that the drive circuit 12 may be provided separately from the base portion 3 or may be provided integrally with the base portion 3.

[0027] The cylindrical member 2 included in the light guide portion 300 is a cylindrical member having a cylindrical axis 20 substantially parallel to the Z axis. The cylindrical member 2 includes a wall portion 22 that serves as a side wall of the cylindrical member, and guides light so as to pass through the inside of the wall portion 22.

[0028] Further, the cylindrical member 2 is a transparent member having transparency to visible light. Preferably, the visible light transmittance of the cylindrical member 2 is 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, or 90% or more. The visible light transmittance is specified as the average value of the transmittances at each wavelength when measured using a spectrophotometer at a measurement wavelength of 380 nm or more and 780 nm or less.

[0029] Such a cylindrical member 2 can be manufactured by molding a resin material. Examples of the resin material include PMMA (Polymethyl methacrylate). However, since the refractive index, strength, moisture resistance, etc. of the cylindrical member 2 vary depending on the resin material, it is not limited to PMMA, and it is preferable to appropriately select a material according to the usage conditions, usage environment, etc. of the lighting device. Further, the cylindrical member 2 can also be configured to include a glass material. A colored material may be used as long as it has transparency to visible light. The processing method is not limited to resin molding, and bending processing, cutting processing, etc. can also be applied.

[0030] As shown in FIG. 2B, the base portion 3 is provided with a groove portion 31 on a flat surface portion, and the LED 11 included in the light source 1 is fixed to the bottom surface of the groove portion 31. Further, the base portion 3 fixes the cylindrical member 2 so as to close the opening portion of the groove portion 31 at an end portion of the wall portion 22 that intersects the cylindrical axis 20.

[0031] The cylindrical member 2 is provided at the bottom of the cylindrical member 2 (the end on the negative Z-axis side) facing the light source 1, and includes a light incident end face 21 through which the light emitted from the light source 1 enters the inside of the wall portion 22. In FIGS. 1, 2A, and 2B, since the light source 1 is disposed facing the bottom of the cylindrical member 2, the light incident end face 21 is included in the bottom of the cylindrical member 2. However, when the light source 1 is disposed facing the top of the cylindrical member 2 (the end on the positive Z-axis side), the light incident end face 21 is included in the top of the cylindrical member 2.

[0032] Also, in FIGS. 1, 2A, and 2B, since the cylindrical axis 20 of the cylindrical member 2 is substantially parallel to the Z-axis, the bottom of the cylindrical member 2 is on the negative Z-axis side of the cylindrical member 2, and the top of the cylindrical member 2 is on the positive Z-axis side of the cylindrical member 2. However, when the cylindrical axis 20 of the cylindrical member 2 is substantially parallel to the X-axis, the bottom of the cylindrical member 2 exists on either the positive or negative X-axis side of the cylindrical member 2, and the top of the cylindrical member 2 exists on the other side of the positive or negative X-axis in the cylindrical member 2.

[0033] Alternatively, when the cylindrical axis 20 of the cylindrical member 2 is substantially parallel to the Y-axis, the bottom of the cylindrical member 2 exists on either the positive or negative Y-axis side of the cylindrical member 2, and the top of the cylindrical member 2 exists on the other side of the positive or negative Y-axis in the cylindrical member 2. In other words, one end in the direction along the cylindrical axis 20 of the cylindrical member 2 corresponds to the bottom, and the other end corresponds to the top.

[0034] Further, the cylindrical member 2 includes a light emitting portion 231 that is included in the inner surface 23 of the cylindrical member 2 intersecting the light incident end face 21 and through which light exits from the inside of the wall portion 22. The inner surface 23 is the inner surface of the cylindrical member 2.

[0035] In FIGS. 2A and 2B, for easy understanding of the description, the light emitting portion 231 is shown by a thick line. However, the light emitting portion 231 corresponds to the portion (region) where light exits on the inner surface 23 and is not a member provided on the inner surface 23.

[0036] Further, the light guide part 300 includes a light extraction part 241 on the outer surface 24 which is the outer surface of the wall part 22 in the cylindrical member 2. The light extraction part 241 is a component configured to emit the light guided through the inside of the wall part 22 from the inside of the wall part 22.

[0037] In FIGS. 1, 2A, and 2B, the light emitted from each of the plurality of LEDs 11 enters the inside of the wall part 22 through the light incident end face 21 and is guided through the inside of the wall part 22. Inside the wall part 22, the light is guided while repeatedly undergoing total reflection at each of the inner surface 23 and the outer surface 24.

[0038] Thereafter, a part of the light guided through the inside of the wall part 22 is reflected, scattered, refracted, or diffracted by the light extraction part 241 toward the inside of the cylindrical member 2 and is emitted from the inside of the wall part 22 to the outside through the light emission part 231.

[0039] The emitted light 232 indicated by the dashed line in FIGS. 1, 2A, and 2B represents the light emitted from the inside of the wall part 22 to the outside. As shown in FIGS. 1, 2A, and 2B, the emitted light 232 is emitted in various directions such as the direction in which the inner surface 23 of the cylindrical member 2 faces from all over the inside of the cylindrical member 2 inside the cylindrical member 2. The lighting device 100 can illuminate the inside of the lighting device 100 from various directions with this emitted light 232. And when an object such as a product or an exhibit is arranged inside the lighting device 100, the object can be illuminated from various directions.

[0040] Note that since the emitted light 232 is also emitted in the vertical direction (Z-axis direction) in FIGS. 1, 2A, and 2B, the lighting device 100 can illuminate light not only in the 360-degree direction around the cylindrical axis 20 but also in the vertical direction (Z-axis direction). In other words, the lighting device 100 can illuminate light not only in the direction parallel to the flat part of the base part 3 but also in the direction intersecting the flat part of the base part 3.

[0041] Next, FIG. 3 is a view showing the base portion 3 and the light source 1 of the lighting device 100. The mounting surface 32 is a surface corresponding to one flat surface portion of the base portion 3, and is a surface where the end portion of the cylindrical member 2 abuts and the cylindrical member 2 is mounted. The groove portion 31 is a depression dug by a predetermined depth from the mounting surface 32, and is a portion formed in an annular shape. The LED 11 is fixed on the bottom surface of the groove portion 31. The cross-sectional shape of the groove of the groove portion 31 is not particularly limited, and may be rectangular or U-shaped, or may include irregularities inside the groove portion 31, but it is preferable to include a flat surface portion in order to stably fix the LED 11.

[0042] Here, the case where the light source 1 is the base portion 3 on the flat plate including the LED 11 is shown, but the form of the light source 1 is not limited thereto. For example, it may be formed so as to cover the light incident end surface 21 of the cylindrical member 2, and an LED may be arranged in an annular housing that fixes the cylindrical member. For example, a groove portion is provided on the upper surface of the annular housing, and an LED is arranged at the bottom of the groove portion. The light incident end surface 21 of the cylindrical member 2 can be inserted into the groove portion to fix the cylindrical member 2 to the annular housing.

[0043] <Configuration Example of Light Extraction Portion> Next, the configuration of the light extraction portion of the light guide portion 300 will be described with reference to FIGS. 4A to 11B. FIGS. 4A to 6B and FIGS. 8A to 11B are partial enlarged views respectively illustrating the detailed configuration of the light extraction portion. FIG. 4A shows the first example, FIG. 4B shows the second example, FIG. 5A shows the third example, FIG. 5B shows the fourth example, FIG. 6A shows the fifth example, and FIG. 6B shows the sixth example. FIGS. 7A and 7B are views showing an example of the configuration of the cylindrical member having the light extraction portion of FIG. 6A, FIG. 7A is a top view, and FIG. 7B is a cross-sectional view taken along the line B-B' of FIG. 7A.

[0044] Furthermore, FIG. 8A shows the seventh example of the detailed configuration of the light extraction portion, FIG. 8B shows the eighth example, FIG. 9A shows the ninth example, FIG. 9B shows the tenth example, FIG. 10A shows the eleventh example, FIG. 10B shows the twelfth example, FIG. 11A shows the thirteenth example, and FIG. 11B shows the fourteenth example.

[0045] First, the light extraction part 241 included in the light guide part 300 shown in FIG. 4A has an optical functional layer 243 that includes an optical cavity 242 inside. The optical functional layer 243 is provided on the outer surface 24. Note that the optical functional layer refers to a layer that exhibits an optical function.

[0046] The optical functional layer 243 is a thin layer formed of a material such as resin and is laminated and provided on the surface of the cylindrical member 2. For example, a layered member including the optical functional layer 243 can be attached to the outer surface 24 by a non-adhesive lamination method such as microwave surface treatment or by adhesion with an adhesive (including a pressure-sensitive adhesive). Further, the optical functional layer 243 is formed in a cylindrical shape along the shape of the outer surface 24.

[0047] Note that layers having other functions such as a cover layer may be included before and after the optical functional layer 243 in the stacking direction.

[0048] The material of the optical functional layer 243 and the material of the adhesive that adheres the optical functional layer 243 to the cylindrical member 2 are preferably those having a refractive index close to that of the cylindrical member 2 in order to suppress refraction and reflection of light at the interface with the cylindrical member 2. For example, it is suitable to use a material including the same PMMA as the cylindrical member 2.

[0049] The optical cavity 242 is an example of a void part and is filled with air inside. However, a material having a refractive index lower than that of the optical functional layer may be filled in the optical cavity 242 instead of air. A plurality of optical cavities 242 are provided regularly or randomly in the optical functional layer 243. The size of the optical cavity 242 can be appropriately selected within the range that can be installed inside the optical functional layer 243.

[0050] The optical functional layer including the optical cavity inside is not particularly limited. For example, the optical functional layers disclosed in International Publication No. WO2011 / 124765, International Publication No. WO2011 / 127187, International Publication No. WO2019 / 087118, and International Publication No. WO2019 / 182091 can be used. These contents are incorporated herein by reference.

[0051] The optical functional layer 243 is produced, for example, by laminating a first film 2431 without a pattern and a second film 2432 with a desired fine pattern by a lamination method, or by adhering them with an adhesive (including a pressure-sensitive adhesive).

[0052] For forming the fine pattern on the second film 2432, laser patterning, direct laser imaging, laser drilling, laser or electron beam irradiation with or without a mask are used. Also, individual characteristics may be imparted by printing, inkjet printing, screen printing, etc. to change the material and refractive index value. Micro / nano dispensing, doping, direct "writing", discrete laser sintering, micro electrical discharge machining (micro EDM), micromachining, microforming, imprinting, embossing, and the like can also be used.

[0053] The light guided inside the wall portion 22 of the cylindrical member 2 passes through the interface between the cylindrical member 2 and the optical functional layer 243 or is refracted at the interface and enters the optical functional layer 243. Then, a part of the light guided inside the optical functional layer 243 is totally reflected at the interface between the optical functional layer 243 and the optical cavity 242 and is guided toward the light emitting portion 231. Among this reflected light, the light incident on the inner surface 23 at an angle not exceeding the critical angle exits from the inside to the outside of the wall portion 22 of the cylindrical member 2. The portion where the light exits within the inner surface 23 corresponds to the light emitting portion 231.

[0054] The light not reflected at the interface between the optical functional layer 243 and the optical cavity 242 is guided while repeating total reflection at the interface between the optical functional layer 243 and the external air. A part of this light is reflected at the interface between the optical cavity 242 and the optical functional layer 243 and exits from the inside to the outside of the wall portion 22 of the cylindrical member 2. The above-described reflection is made at each of the plurality of optical cavities 242 provided in the optical functional layer 243.

[0055] In this way, the light extraction unit 241 can emit light from the light emitting unit 231 inside the inner surface 23. The angle of the interface between the optical functional layer 243 and the optical cavity 242 is predetermined at a suitable angle according to the application of the lighting device.

[0056] Next, the light extraction unit 241a included in the light guide unit 300a shown in FIG. 4B has an optical functional layer 245 that contains light scattering particles 244 inside. The optical functional layer 245 is provided on the outer surface 24. The material and installation method of the optical functional layer 245 are the same as those of the above-described optical functional layer 243.

[0057] The light scattering particles 244 have a refractive index difference with respect to the material constituting the optical functional layer 245, and are particles having an average particle diameter of about 0.3 to 5 μm. The light scattering particles 244 are an example of a light scatterer that scatters light guided inside the wall portion 22. A plurality of light scattering particles 244 are contained in the material constituting the optical functional layer 245. The optical functional layer containing light scattering particles inside is not particularly limited, but for example, the optical functional layer disclosed in JP-A-2013-195811 can be used. These contents are incorporated herein by reference. Here, the average particle diameter is the volume average particle diameter, and can be measured using, for example, an ultracentrifugal automatic particle size distribution measuring device.

[0058] The light guided inside the wall portion 22 enters the optical functional layer 245 by passing through the interface between the cylindrical member 2 and the optical functional layer 245 or refracting at the interface. Then, a part of the light guided inside the optical functional layer 245 is scattered at the interface between the optical functional layer 245 and the light scattering particles 244, and is guided toward the light emitting unit 231. Among this scattered light, the light that enters the inner surface 23 at an angle not exceeding the critical angle exits from the inside to the outside of the wall portion 22 in the cylindrical member 2. The portion where the light exits inside the inner surface 23 corresponds to the light emitting unit 231.

[0059] The light that is not scattered at the interface between the optical functional layer 245 and the light-scattering particles 244 is guided while repeating total reflection at the interface between the optical functional layer 245 and the external air. A part of this light is scattered at the interface between the light-scattering particles 244 and the optical functional layer 245 and is emitted from the inside to the outside of the wall portion 22 in the cylindrical member 2. The above-described scattering occurs at each of the plurality of light-scattering particles 244 provided in the optical functional layer 245.

[0060] In this way, the light extraction portion 241a can emit light from the light emitting portion 231 within the inner surface 23.

[0061] Next, the light extraction portion 241b included in the light guide portion 300b shown in FIG. 5A has an optical functional layer 243 that includes a light cavity 242 therein. The optical functional layer 243 is provided on the inner surface 23. The material and function of the optical functional layer 243 are the same as those of the optical functional layer 243 in the light extraction portion 241. The portion where the optical functional layer 243 is provided within the inner surface 23 corresponds to the light emitting portion 231.

[0062] Also, the light extraction portion 241c included in the light guide portion 300c shown in FIG. 5B has an optical functional layer 245 that includes light-scattering particles 244 therein. The optical functional layer 245 is provided on the inner surface 23. The material and function of the optical functional layer 245 are the same as those of the optical functional layer 245 in the light extraction portion 241a. The portion where the optical functional layer 245 is provided within the inner surface 23 corresponds to the light emitting portion 231.

[0063] Next, the light extraction portion 241d included in the light guide portion 300d shown in FIG. 6A has a light cavity 246. The light cavity 246 is provided within the wall portion 22d of the cylindrical member 2d.

[0064] The optical cavity 246 is an example of a void portion and is filled with air inside. However, the optical cavity 246 may be filled with a material having a refractive index lower than that of the cylindrical member 2d instead of air. A plurality of optical cavities 246 are provided regularly or randomly in the wall portion 22d of the cylindrical member 2d. The size of the optical cavity 246 can be appropriately selected within the range that can be installed in the wall portion 22d of the cylindrical member 2d.

[0065] The method for manufacturing the cylindrical member 2d is not particularly limited. For example, a method of winding a film having a desired fine pattern formed on the outer surface of the first cylindrical member 201 to form the second cylindrical member 202 may be used.

[0066] Alternatively, a method of winding a film having no pattern formed on the inner surface of the second cylindrical member 202 to form the first cylindrical member 201 may be used. Alternatively, it may be manufactured by connecting one end of a plate-like member formed by bonding a first film having no pattern and a second film having a desired fine pattern formed thereon to the other end with an adhesive or the like. In this case, the first cylindrical member 201 is formed from the first film, and the second cylindrical member 202 is formed from the second film.

[0067] Note that the bonding between the members is performed by laminating the first film and the second film by a lamination method such as microwave surface treatment without an adhesive, or by using an adhesive (including a pressure-sensitive adhesive).

[0068] Alternatively, it may be manufactured by bonding a first cylindrical member 201 having no pattern formed thereon and a second cylindrical member 202 having a desired fine pattern formed thereon by a lamination method such as microwave surface treatment without an adhesive, or by bonding them with an adhesive (including a pressure-sensitive adhesive). In order to suppress interface reflection, it is preferable that the refractive indices of the first cylindrical member 201 and the second cylindrical member 202 are substantially equal, and when bonding with an adhesive, the refractive index of the adhesive is substantially equal to that of the first cylindrical member 201 and the second cylindrical member 202.

[0069] For forming the fine pattern on the second cylindrical member 202, the same method as that for forming the fine pattern on the second film 2432 described above can be applied. Also, the function of the optical cavity 246 is the same as that of the optical cavity 242 described with reference to FIGS. 4A and 5A.

[0070] Next, the light extraction part 241e of the light guide part 300e shown in FIG. 6B has light scattering particles 247. The light scattering particles 247 are provided in the wall part 22e of the cylindrical member 2e. The light scattering particles 247 have a refractive index difference with respect to the material constituting the cylindrical member 2e, and are particles having an average particle diameter of about 0.3 to 5 μm, and are an example of a light scatterer that scatters the light guided in the wall part 22e. The light scattering particles 247 are contained in the material constituting the cylindrical member 2e. The function of the light scattering particles 247 is the same as that of the light scattering particles 244 described with reference to FIGS. 4B and 5B.

[0071] FIGS. 7A and 7B show an example of the configuration of the cylindrical member 2d having the light extraction part 241d of FIG. 6A. As shown in FIGS. 7A and 7B, the cylindrical member 2d has a first cylindrical member 201 on which a desired fine pattern is formed and a second cylindrical member 202 on which no pattern is formed. A film on which a desired fine pattern is formed is wound around the outer surface of the first cylindrical member 201 to form the second cylindrical member 202.

[0072] Alternatively, the first cylindrical member 201 and the second cylindrical member 202 are bonded together by a lamination method such as an adhesive-free microwave surface treatment or are adhered by an adhesive. An optical cavity 246 is formed between the fine pattern on the first cylindrical member 201 and the surface of the second cylindrical member 202.

[0073] Next, the light extraction part 241f of the light guide part 300f shown in FIG. 8A has an optical function layer 249 including a prism part 248 on the surface. The optical function layer 249 is provided on the outer surface 24. The prism part 248 is a part including a fine inclined surface capable of deflecting light.

[0074] The optical functional layer 249 is preferably made of a material having a refractive index close to that of the cylindrical member 2 in order to suppress the refraction and reflection of light at the interface between the cylindrical member 2 and the light extraction portion 241f. For example, it can be configured to include the same PMMA as the cylindrical member 2. A plurality of prism portions 248 are provided regularly or randomly on the surface of the optical functional layer 249. The size and adjacent intervals of the prism portions 248 can be appropriately selected within the range that can be formed on the optical functional layer 249.

[0075] For forming the prism portions 248 on the optical functional layer 249, the same method as that for forming the fine pattern on the second film 2432 described above can be applied.

[0076] The light guided inside the wall portion 22 passes through the interface between the cylindrical member 2 and the optical functional layer 249 or is refracted at the interface and enters the inside of the optical functional layer 243. Then, it is guided inside the optical functional layer 249, reflected by the prism portions 248, and guided toward the light emitting portion 231. Among this reflected light, the light that enters the inner surface 23 at an angle not exceeding the critical angle exits from the inside to the outside of the wall portion 22 in the cylindrical member 2. The portion where the light exits within the inner surface 23 corresponds to the light emitting portion 231. The above reflection is performed by the plurality of prism portions 248 provided on the optical functional layer 249.

[0077] In this way, the light extraction portion 241f can emit light from the light emitting portion 231 within the inner surface 23. Note that the angle of the inclined surface in the prism portion 248 is predetermined to be a suitable angle according to the use of the lighting device.

[0078] Next, the light extraction portion 241g included in the light guide portion 300g shown in FIG. 8B has an optical functional layer 251 including concavo-convex portions 250 on its surface. The optical functional layer 251 is provided on the outer surface 24. The material of the optical functional layer 251 is the same as that of the optical functional layer 249 described above. The concavo-convex portions 250 are portions where a plurality of concave or convex portions having a width and height of about 1 to 5 μm are formed. The concavo-convex portions 250 are randomly formed on the surface of the optical functional layer 251 and scatter the light guided inside the optical functional layer 251.

[0079] For forming the uneven portions 250 on the optical functional layer 251, the same method as that for forming the fine patterns on the second film 2432 described above can be applied. Also, since the uneven portions 250 may be random rough surfaces, blasting or the like can also be applied.

[0080] The light guided inside the wall portion 22 passes through the interface between the cylindrical member 2 and the optical functional layer 251 or is refracted at the interface and enters the inside of the optical functional layer 251. Then, a part of the light guided inside the optical functional layer 251 is scattered at the interface between the optical functional layer 251 and the uneven portions 250 and is guided toward the light emitting portion 231. Among this scattered light, the light that enters the inner surface 23 at an angle not exceeding the critical angle is emitted to the outside from inside the cylindrical member 2. The portion where the light is emitted inside the inner surface 23 corresponds to the light emitting portion 231. The above-described scattering is performed at each of the plurality of uneven portions 250 provided in the optical functional layer 251.

[0081] In this way, the light extraction portion 241g can emit light from the light emitting portion 231 inside the inner surface 23.

[0082] Next, the light extraction portion 241h included in the light guide portion 300h shown in FIG. 9A has an optical functional layer 249 including a prism portion 248 on its surface. The optical functional layer 249 is provided on the inner surface 23. The material and function of the optical functional layer 249 are the same as those of the optical functional layer 249 in the light extraction portion 241f. However, in this case, more light is reflected by surfaces other than the inclined surfaces such as the surface 248' substantially parallel to the Y axis in the prism portion 248. Note that the portion where the optical functional layer 249 is provided inside the inner surface 23 corresponds to the light emitting portion 231.

[0083] Also, the light extraction portion 241i included in the light guide portion 300i shown in FIG. 9B has an optical functional layer 251 including uneven portions 250 on its surface. The optical functional layer 251 is provided on the inner surface 23. The material and function of the optical functional layer 251 are the same as those of the optical functional layer 251 in the light extraction portion 241g. Note that the portion where the optical functional layer 251 is provided inside the inner surface 23 corresponds to the light emitting portion 231.

[0084] Next, the light extraction part 241j included in the light guide part 300j shown in FIG. 10A has a prism part 252. The prism part 252 is formed on at least a part of the outer surface 24. The prism part 252 is a part including fine inclined surfaces capable of deflecting light. A plurality of prism parts 252 are provided regularly or randomly on the surface of the outer surface 24. The size of the inclined surfaces in the prism part 252 and the intervals between adjacent ones can be appropriately selected within the range that can be formed on the outer surface 24. The light deflected by the prism part 252 passes through the light emitting part 231 and is emitted.

[0085] For forming the prism part 252 on the outer surface 24, the same method as for forming the prism part 248 on the above-described optical function layer 249 can be applied. Also, the function of the prism part 252 is the same as that of the prism part 248 described with reference to FIGS. 8A and 9A.

[0086] Also, the light extraction part 241k included in the light guide part 300k shown in FIG. 10B has a concavo-convex part 253. The concavo-convex part 253 is formed on at least a part of the outer surface 24. The concavo-convex part 253 is a part where a plurality of concave or convex parts having a width and height of about 1 to 5 μm are formed. The concavo-convex part 253 is formed randomly on the outer surface 24 and scatters the light guided inside the wall part 22. The light scattered by the concavo-convex part 253 passes through the light emitting part 231 and is emitted.

[0087] For forming the concavo-convex part 253 on the outer surface 24, the same method as for forming the concavo-convex part 250 on the above-described optical function layer 251 can be applied. Also, the function of the concavo-convex part 253 is the same as that of the concavo-convex part 250 described with reference to FIGS. 8B and 9B.

[0088] Next, the light extraction part 241m included in the light guide part 300m shown in FIG. 11A has a prism part 252. The prism part 252 is formed on at least a part of the inner surface 23. The prism part 252 is the same as the prism part 252 in the light extraction part 241j, but in this case, more light is reflected by surfaces other than inclined surfaces such as the surface 252' substantially parallel to the Y axis in the prism part 252. Note that the part where a plurality of prism parts 252 are formed within the inner surface 23 corresponds to the light emitting part 231.

[0089] In addition, the light extraction part 241n included in the light guide part 300n shown in FIG. 10B has the uneven part 253. The uneven part 253 is formed on at least a part of the inner surface 23. The uneven part 253 is the same as the uneven part 253 in the light extraction part 241k. Note that the part where a plurality of uneven parts 253 are formed within the inner surface 23 corresponds to the light emitting part 231.

[0090] <Effects of the lighting device 100> Next, the effects of the lighting device 100 will be described.

[0091] Conventionally, a lighting device for illuminating an object such as a product or an exhibit in a showcase has been known. In addition, a configuration having a light guide body having at least one light incident surface facing a light source and a light emitting surface substantially orthogonal thereto, and a prism sheet disposed on the light emitting surface of the light guide body has been disclosed.

[0092] However, in the conventional configuration, since a plate-like member is used as the light guide body, light cannot be illuminated in a direction other than the direction in which the flat portion of the plate-like member faces, or even if it can be illuminated, only a small amount of light can be illuminated compared to the illumination light in the direction in which the flat portion faces. Therefore, there is room for improvement in illuminating an object from various directions.

[0093] In the present embodiment, the light guide part 300 included in the lighting device 100 has a cylindrical member 2 and a light extraction part 241 that emits light guided through the inside of the wall part 22 of the cylindrical member 2 from the inside of the wall part 22.

[0094] In addition, the cylindrical member 2 is provided at the bottom of the cylindrical member 2 facing the light source 1, and has a light incident end face 21 through which the light emitted from the light source 1 enters the inside of the wall part 22, and a light emitting part 231 included in the inner surface 23 of the cylindrical member 2 that intersects the light incident end face 21 and from which light is emitted from the inside of the wall part 22.

[0095] The light emitted by the light source 1 enters the inside of the wall portion 22 in the cylindrical member 2 through the light incident end face 21 and is guided inside the wall portion 22. A part of the guided light is reflected, scattered, refracted or diffracted by the light extraction portion 241 toward the inside of the cylindrical member 2, and exits from the inside of the wall portion 22 to the outside through the light emission portion 231.

[0096] With this configuration, the lighting device 100 can emit light in various directions such as the direction in which the inner surface 23 of the cylindrical member 2 faces from all over the inside of the cylindrical member 2 inside the cylindrical member 2. Since the inner surface 23 of the cylindrical member 2 exists in a 360-degree azimuth around the cylindrical axis 20 of the cylindrical member 2, the inside of the cylindrical member 2 can be illuminated from various directions as compared with the conventional case. And when an object such as a product or an exhibit is arranged inside the lighting device 100, a lighting device capable of illuminating the object from various directions can be provided.

[0097] In addition, since the lighting device 100 has a transparent and cylindrical appearance, it can exhibit excellent design. Furthermore, an object arranged inside the lighting device 100 can be illuminated from various directions without dead angles (spaces not illuminated by light).

[0098] Also, in the present embodiment, by suppressing the directivity of light by emitting light from a wide area in the light emission portion 231, specularly reflected light from an illuminated surface or the like can be suppressed, and glare can be suppressed. Thereby, while suppressing glare, an object arranged inside the lighting device 100 can be illuminated from various directions.

[0099] Also, in a conventional lighting device, when an LED is used as a light source, multiple shadows are generated due to the high directivity of the light emitted by the LED, etc., making it difficult to observe an object arranged inside the lighting device 100.

[0100] In the present embodiment, by suppressing the directivity of light by emitting light from a wide area in the light emission portion 231, such multiple shadows are eliminated, and the space is illuminated with natural light and shadows. Thereby, an object arranged inside the lighting device 100 can be easily observed.

[0101] Also, in this embodiment, since the light guide unit 300 having transparency to visible light is used, the user can see through to the other side of the light guide unit. Thereby, a comfortable space can be provided without impairing the expansion of the space.

[0102] Here, the visible light transmittance of the light guide unit 300 including the cylindrical member 2 and the light extraction unit 241, etc. is preferably 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, or 90% or more. The visible light transmittance is specified as the average value of the transmittances at each wavelength when measured using a spectrophotometer at a measurement wavelength of 380 nm or more and 780 nm or less.

[0103] Also, the divergence angle of the light emitted from the light emitting unit 231 can be made anisotropic. For example, it is possible to emit light from the light emitting unit 231 such that the divergence angle is large in the X-axis direction in FIG. 1 and small in the Z-axis direction.

[0104] <Modification Example of the First Embodiment> Here, in the above-described embodiment, a cylindrical member is exemplified as the cylindrical member 2, but it is not limited thereto. The cylindrical member 2 may be a cylindrical member having a polygonal cross-section such as a quadrilateral, a triangle, or a hexagon.

[0105] FIGS. 12A, 12B, and 12C are perspective views showing an example of the configuration of an illumination device according to a modification example of the first embodiment. FIG. 12A shows a first modification example, FIG. 12B shows a second modification example, and FIG. 12C shows a third modification example.

[0106] As shown in FIG. 12A, the illumination device 100p has a light guide unit 300p. The light guide unit 300p has a cylindrical member 2p. The cylindrical member 2p is a cylindrical member having a square cross-section. With this configuration, the illumination device 100p can illuminate light in various directions including four directions where each surface parallel to the central axis 20p of the cylindrical member 2p faces inside the cylindrical member 2p.

[0107] Also, as shown in FIG. 12B, the lighting device 100q includes a light guide unit 300q. The light guide unit 300q includes a cylindrical member 2q. The cylindrical member 2q is a cylindrical member having a triangular cross section. With this configuration, the lighting device 100q can illuminate light in various directions including three directions in which each surface parallel to the central axis 20q of the cylindrical member 2q faces inside the cylindrical member 2q.

[0108] Also, as shown in FIG. 12C, the lighting device 100r includes a light guide unit 300r. The light guide unit 300r includes a cylindrical member 2r. The cylindrical member 2r is a cylindrical member having a hexagonal cross section. With this configuration, the lighting device 100r can illuminate light in various directions including six directions in which each surface parallel to the central axis 20r of the cylindrical member 2r faces inside the cylindrical member 2r.

[0109] Thus, even with a quadrilateral, a triangle, and a hexagon, the same effects as those of the lighting device 100 according to the first embodiment can be obtained. Note that, in addition to the circular, quadrilateral, triangular, and hexagonal shapes described above, various other shapes can be applied to the cross section of the cylindrical member, and the same effects as those of the lighting device 100 can be obtained. Also, regardless of the shape of the cross section of the cylindrical member, the light extraction portions 241, 241a to 241n can all be applied. However, it is preferable that the optical function layer in the light extraction portion is formed in a shape along the shape of the outer surface or the inner surface of the cylindrical member.

[0110] [Second Embodiment] Next, the lighting device 100s according to the second embodiment will be described. Note that the same components as those described in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and redundant descriptions will be omitted as appropriate. This also applies to each of the embodiments and modification examples described hereinafter.

[0111] In this embodiment, a low refractive index layer having a refractive index lower than that of the cylindrical member is provided on at least a part of at least one of the outer surface and the inner surface of the cylindrical member that guides light. Thereby, light loss caused by light guided inside the wall portion of the cylindrical member leaking from the cylindrical member due to scratches, dirt, fingerprints, etc. of the cylindrical member is prevented, and the utilization efficiency of light is improved. Note that the low refractive index layer may be provided by being formed on at least a part of at least one of the outer surface and the inner surface of the cylindrical member, or may be provided by being bonded to the cylindrical member via an adhesive (including a pressure-sensitive adhesive).

[0112] FIGS. 13A and 13B are diagrams for explaining an example of the function of the low refractive index layer 34 in the lighting device 100s. FIG. 13A is a diagram showing the lighting device 100s having the low refractive index layer, and FIG. 13B is a diagram showing the lighting device 100X according to a comparative example having no low refractive index layer.

[0113] As shown in FIG. 13A, the lighting device 100s has a light guide portion 300s. In the light guide portion 300s, an optical function layer 243, a low refractive index layer 34, and a cover layer 35 are laminated and formed on the surface of the cylindrical member 2 in this order. Note that a layer having other functions may be included between the surface of the cylindrical member 2 and the low refractive index layer 34.

[0114] Moreover, the visible light transmittance of the light guide portion 300s having the cylindrical member 2, the optical function layer 243, the low refractive index layer 34, and the cover layer 35 is preferably 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, or 90% or more. The visible light transmittance is specified as the average value of the transmittances at each wavelength when measured using a spectrophotometer at a measurement wavelength of 380 nm or more and 780 nm or less.

[0115] The low-refractive index layer 34 is a layer having a refractive index lower than that of the cylindrical member 2. When the cylindrical member 2 is mainly composed of PMMA, the refractive index n1 of the cylindrical member 2 is approximately 1.49. In comparison, the refractive index n2 of the low-refractive index layer 34 is preferably 1.30 or less, and more preferably 1.20 or less. The low-refractive index layer is not particularly limited, but for example, a low-refractive index layer having voids as disclosed in WO 2019 / 146628 A1 can be used, the contents of which are incorporated herein by reference.

[0116] When the angle of incidence of light guided inside the wall portion 22 of the cylindrical member 2 on the low refractive index layer 34 is larger than the critical angle (when the light is incident at a shallow angle), the total reflection condition is satisfied, and the light is totally reflected at the interface between the wall portion 22 and the low refractive index layer 34. Here, the critical angle θc is expressed by the following equation. θc=θi=arcsin(n2 / n1) Note that θi is the angle of incidence (angle from the normal).

[0117] The cover layer 35 is intended to protect the cylindrical member 2, and is preferably one that is highly transparent to visible light. It may be made of glass, plastic, or the like, and may have an ultraviolet absorbing effect. From the perspective of a protective layer, it is better to have high strength, but it may also be a thin, flexible layer.

[0118] 13B has an optical function layer 243 and a cover layer 35 laminated in this order on the surface of a cylindrical member 2 included in a light-guiding section 300X, and does not have a low refractive index layer. In this case, if foreign matter C such as scratches, dirt, fingerprints, sweat, or dust is attached to the surface of the cover layer 35, light guided inside the wall section 22 that is directed toward the cover layer 35 may be scattered by the foreign matter C and leak from inside the wall section 22 to the outside, resulting in light loss.

[0119] On the other hand, in the lighting device 100s, since the low refractive index layer 34 is provided between the cover layer 35 and the cylindrical member 2, the light guided inside the wall portion 22 is totally reflected by the low refractive index layer 34 before reaching the cover layer 35, as shown in Fig. 13A. Thereby, it is possible to prevent the light guided inside the wall portion 22 from reaching the foreign matter C, prevent light loss caused by scratches, dirt, fingerprints, etc., and improve the light utilization efficiency.

[0120] In addition, other effects are the same as those described in the first embodiment.

[0121] Further, the above effects can be obtained by providing the low refractive index layer 34 on at least a part of at least one of the outer surface or the inner surface of the cylindrical member 2. Further, the above effects can also be obtained by providing the low refractive index layer 34 in a region where the optical function layer 243 is not provided on at least one of the outer surface or the inner surface.

[0122] In addition, in Figs. 13A and 13B, a configuration in which the low refractive index layer 34 is provided on the optical function layer 243 including the optical cavity 242 is illustrated, but the present invention is not limited thereto. The low refractive index layer 34 can be provided on the optical function layers 245, 249 or 251 including light scattering particles, and the low refractive index layer 34 can also be provided on the prism portion 252 or the concavo-convex portion 253.

[0123] [Third Embodiment] Next, with reference to Figs. 14A and 14B, the lighting device 100t according to the third embodiment will be described. Figs. 14A and 14B are diagrams for explaining an example of the configuration of the lighting device 100t, Fig. 14A is a top view, and Fig. 14B is a cross-sectional view taken along the line C-C' of Fig. 14A.

[0124] As shown in Figs. 14A and 14B, the lighting device 100t has a light guide portion 300t. The light guide portion 300t also has a lid member 4. The lid member 4 is a member disposed on the end surface 25 on the side opposite to the light incident end surface 21 of the cylindrical member 2. The lid member 4 is a disc-shaped member having a diameter substantially equal to the diameter of the cylinder of the cylindrical member 2.

[0125] In FIGS. 14A and 14B, in order to illustrate an arrangement in which the cylindrical axis 20 of the cylindrical member 2 is parallel to the Z-axis and the light incident end face 21 is on the negative Z-axis side, the arrangement position of the lid member 4 is on the positive Z-axis side of the wall portion 22 in the cylindrical member 2. However, the arrangement position of the lid member 4 is not limited thereto. For example, in the case of an arrangement in which the cylindrical axis 20 of the cylindrical member 2 is parallel to the Z-axis and the light incident end face 21 is on the positive Z-axis side, the arrangement position of the lid member 4 is on the negative Z-axis side of the wall portion 22. Further, when the cylindrical axis 20 of the cylindrical member 2 is parallel to the X-axis or the Y-axis, the arrangement position of the lid member 4 corresponds to either the positive X-axis side or the negative X-axis side of the wall portion 22, or either the positive Y-axis side or the negative Y-axis side of the wall portion 22.

[0126] Such a lid member 4 is configured to include a material such as resin, glass, or metal. The material of the lid member 4 may be the same as or different from the material of the cylindrical member 2. However, in order to be unified with the transparent cylindrical member 2, it is preferably made of a transparent material.

[0127] In FIGS. 14A and 14B, an example is shown in which the lid member 4 is a disk-shaped member having a diameter substantially equal to the diameter of the cylinder of the cylindrical member 2. However, the present invention is not limited thereto. The lid member 4 may have a diameter larger than the diameter of the cylinder of the cylindrical member 2, or may have a shape other than a circular shape such as a rectangle. Further, the lid member 4 is not limited to a plate-like member, and may be a member having a hemispherical shape or the like.

[0128] Furthermore, in FIGS. 14A and 14B, an example is shown in which the lid member 4 is placed on the end face 25 of the cylindrical member 2. However, the present invention is not limited thereto. The lid member may be arranged so as to cover the end of the cylindrical member 2 on the side opposite to the light incident end face 21.

[0129] Alternatively, the lid member 4 may be fixed to the cylindrical member 2 by adhesion or the like, or may be fixed by fitting when the lid member 4 is placed over the end of the cylindrical member 2. Alternatively, it may be configured not to be fixed by simply placing the lid member 4 on the end face 25. Further, the lid member 4 may be configured such that the light guided inside the wall portion 22 is further guided into the lid member 4 via the joint surface between the wall portion 22 and the lid member 4. In this case, the lid member 4 may include a light extraction portion as described in the first embodiment in order to emit the light guided inside the lid member 4 to the outside.

[0130] By providing the lid member 4 in this way, for example, it is possible to prevent dust and dirt from entering the inside of the cylindrical member 2 and to improve the appearance.

[0131] In addition, other effects are the same as those described in the first embodiment. Also, by applying the second embodiment to the third embodiment, the same effects as those of the second embodiment can be obtained.

[0132] [Fourth Embodiment] Next, with reference to FIGS. 15A and 15B, the lighting device 100u according to the fourth embodiment will be described. FIGS. 15A and 15B are diagrams for explaining an example of the configuration of the lighting device 100u, FIG. 15A is a top view, and FIG. 15B is a cross-sectional view taken along the line D-D' of FIG. 15A. As shown in FIGS. 15A and 15B, the lighting device 100u has a light guide portion 300u. The light guide portion 300u has a cylindrical member 2u.

[0133] The cylindrical member 2u is formed in a tapered shape that becomes thinner as it moves away from the light incident end face 21u. The direction in which it moves away from the light incident end face 21u corresponds to the positive Z-axis direction in the examples of FIGS. 15A and 15B. Further, a light extraction portion 241u is provided on the outer surface 24u of the cylindrical member 2u. The light extraction portion 241u may be provided by forming a prism portion or an uneven portion on at least a part of the outer surface 24u, or may be provided by bonding an optical functional layer to the cylindrical member 2u via an adhesive (including a pressure-sensitive adhesive).

[0134] The light extraction unit 241u can reflect, scatter, refract, or diffract the light guided inside the wall portion 22u of the cylindrical member 2u toward the inner surface 23u, and emit the light from the inside of the wall portion 22u to the outside through the light emission portion 231u.

[0135] Even with a configuration including the cylindrical member 2u formed in a tapered shape that becomes thinner as it moves away from the light incident end face 21u, the same effects as those of the first embodiment can be obtained. Note that other effects are the same as those described in the first embodiment.

[0136] Also, although a configuration in which the cross-section of the cylindrical member 2u is substantially circular has been illustrated, the cylindrical member may have a shape other than a substantially circular shape such as a triangle, a quadrilateral, or a hexagon. Further, the second and third embodiments can be applied to the lighting device 100u to obtain the same effects as those of the second and third embodiments. Also, not only the light extraction unit 241 but also the light extraction units 241a to 241n can be applied to the lighting device 100u. However, it is preferable that the optical function layer in the light extraction unit is formed in a shape along the shape of the outer surface 24u or the inner surface 23u of the cylindrical member 2u.

[0137] <First Modification of the Fourth Embodiment> Next, FIGS. 16A and 16B are diagrams for explaining an example of the configuration of a lighting device 100v according to the first modification of the fourth embodiment. FIG. 16A is a top view, and FIG. 16B is a cross-sectional view taken along the line E-E' of FIG. 16A. As shown in FIGS. 16A and 16B, the lighting device 100v has a light guide unit 300v. The light guide unit 300v has a cylindrical member 2v.

[0138] The cylindrical member 2v is formed in a tapered shape that becomes thinner as it approaches the light incident end face 21v. The direction approaching the light incident end face 21v corresponds to the negative Z-axis direction in the examples of FIGS. 16A and 16B. A light extraction unit 241v is provided on the outer surface 24v of the cylindrical member 2v. The light extraction unit 241v may be provided by forming at least a part of the outer surface 24v with a prism portion or an uneven portion, or may be provided by bonding an optical function layer to the cylindrical member 2v via an adhesive (including a pressure-sensitive adhesive).

[0139] The light extraction unit 241v can reflect, scatter, refract, or diffract the light guided inside the wall portion 22v of the cylindrical member 2v toward the inner surface 23v, and emit the light from the inside of the wall portion 22v to the outside through the light emission unit 231v.

[0140] Except that the tapered shape of the cylindrical member 2v becomes thinner as it approaches the light incident end face 21v, the lighting device 100v is the same as the lighting device 100u, so the overlapping description is omitted here.

[0141] <Second Modified Example of the Fourth Embodiment> Next, FIGS. 17A and 17B are diagrams for explaining an example of the configuration of a lighting device 100w according to a second modified example of the fourth embodiment. FIG. 17A is a top view, and FIG. 17B is a cross-sectional view taken along the line F-F' of FIG. 17A. As shown in FIGS. 17A and 17B, the lighting device 100w has a light guide unit 300w. The light guide unit 300w has a cylindrical member 2w.

[0142] The cylindrical member 2w has a conical shape connected to a tapered tip portion 26 that becomes thinner as it moves away from the light incident end face 21w. The tip portion 26 surrounded by a dashed-dotted circle in FIG. 17B corresponds to the tapered tip portion. A light extraction unit 241w is provided on the outer surface 24w of the cylindrical member 2w. The light extraction unit 241w may be provided by forming a prism portion, an uneven portion, or the like on at least a part of the outer surface 24w, or may be provided by bonding an optical functional layer to the cylindrical member 2w via an adhesive (including a pressure-sensitive adhesive).

[0143] The light extraction unit 241w can reflect, scatter, refract, or diffract the light guided inside the wall portion 22w of the cylindrical member 2w toward the inner surface 23w, and emit the light from the inside of the wall portion 22w to the outside through the light emission unit 231w.

[0144] Except for the point where the conical shape with the tapered tip 26 is connected, the lighting device 100w is the same as the lighting device 100u, so overlapping explanations are omitted. However, since the tapered tip 26 of the lighting device 100w is connected, it is possible to prevent dust and dirt from entering the inside of the cylindrical member 2w without providing the lid member 4 and the like shown in FIGS. 14A and 14B.

[0145] In addition, in FIGS. 17A and 17B, a configuration in which the cylindrical member 2w has a conical shape is illustrated, but the present invention is not limited thereto, and the cylindrical member 2w may have various pyramid-like shapes such as a triangular pyramid, a quadrangular pyramid, or a hexagonal pyramid. Further, since the cylindrical member 2w has a pyramid-like shape, it can also be referred to as a pyramid-like member.

[0146] [Fifth Embodiment] Next, with reference to FIGS. 18, 19A, and 19B, the lighting device 100y according to the fifth embodiment will be described. FIG. 18 is a perspective view for explaining an example of the configuration of the lighting device 100y. FIGS. 19A and 19B are views for explaining an example of the configuration of the lighting device 100y, FIG. 19A is a top view, and FIG. 19B is a cross-sectional view taken along the line G-G' of FIG. 19A.

[0147] As shown in FIGS. 18, 19A, and 19B, the lighting device 100y has a light guide unit 300y. The light guide unit 300y has a cylindrical member 2y. However, unlike the cylindrical member 2, the cylindrical member 2y is such that the ends of the plate-like member are not connected to the other end. The cylindrical member 2y is a member formed by winding a plate-like member into a cylinder. The material of the cylindrical member 2y can be the same as that of the cylindrical member 2.

[0148] As also shown in FIGS. 19A and 19B, a light extraction portion 241y is provided on the outer surface 24y of the cylindrical member 2y. The light extraction portion 241y may be provided by forming at least a part of the outer surface 24y with a prism portion or an uneven portion, or may be provided by bonding an optical functional layer to the cylindrical member 2y via an adhesive (including a pressure-sensitive adhesive).

[0149] The light extraction unit 241y can reflect, scatter, refract, or diffract the light guided inside the wall portion 22y in the cylindrical member 2y toward the inner surface 23y, and emit the light from the inside of the wall portion 22y to the outside through the light emitting portion 231y.

[0150] Thus, even in a configuration including the cylindrical member 2y formed by winding either the plate-like member or the sheet-like member into a cylindrical shape, the same effects as those of the first embodiment can be obtained. In other words, the cylindrical member may have a configuration in which the end portion of the plate-like member is not connected to the other end portion, or a configuration in which a part of the cylinder along the circumferential direction is missing, and the same effects as those of the first embodiment can be obtained with these configurations.

[0151] Note that other effects are the same as those described in the first embodiment.

[0152] In addition, although a configuration in which the cross section of the cylindrical member 2y is substantially circular has been illustrated, the cylindrical member may have a shape other than a substantially circular shape such as a triangle, a quadrilateral, or a hexagon. Note that the cylindrical member 2y shown in FIGS. 18, 19A, and 19B is formed such that a part of the outer surface is in contact with a part of the inner surface, but the present invention is not limited to this form, and a part of the outer surface may be formed without being in contact with a part of the inner surface.

[0153] In addition, each of the second to fourth embodiments can be applied to the lighting device 100y, and the same effects as those of each of the second to fourth embodiments can be obtained. In addition, not only the light extraction unit 241 but also the light extraction units 241a to 241n can be applied to the lighting device 100y. However, it is preferable that the optical function layer in the light extraction unit is formed in a shape along the shape of the outer surface or the inner surface of the cylindrical member 2y.

[0154] [Sixth Embodiment] Next, with reference to FIGS. 20, 21A, and 21B, a lighting device 100z according to the sixth embodiment will be described. FIG. 20 is a perspective view for explaining an example of the configuration of the lighting device 100z. FIGS. 21A and 21B are diagrams for explaining an example of the configuration of the lighting device 100z, FIG. 21A is a top view, and FIG. 21B is a cross-sectional view taken along the line H-H' of FIG. 21A.

[0155] As shown in FIGS. 20, 21A, and 21B, the lighting device 100z has a light guide portion 300z. The light guide portion 300z has a curved surface member 2z. The curved surface member 2z is a hollow hemispherical member. In other words, the curved surface member 2z is a hollow hemisphere that is a part of a hollow sphere. As the material of the curved surface member 2z, the same material as that of the cylindrical member 2 can be applied.

[0156] The curved surface member 2z and the installation surface 3z of the curved surface member 2z on the base portion 3 form a sealed space. The installation surface 3z is the surface on the positive Z-axis side of the base portion 3 and is an example of the installation surface of the curved surface member. Here, the sealed space means a space that is completely closed by the curved surface member 2z and the installation surface 3z and is not open to the outside.

[0157] The lighting device 100z is configured such that the curved surface member 2z can be removed from the installation surface 3z. When the lighting device 100z illuminates an object, before starting the illumination, the curved surface member 2z is removed and the object is placed on the installation surface 3z. Then, the curved surface member 2z is installed on the installation surface 3z and the illumination is started. In this way, the object can be placed in the sealed space formed by the curved surface member 2z and the installation surface 3z.

[0158] The method for manufacturing the spherical surface member is not particularly limited. For example, it can be manufactured by pressing a mold of a desired shape against a plate-like member to process the plate-like member.

[0159] Also, as shown in FIGS. 21A and 21B, a light extraction portion 241z is provided on the outer surface 24z of the curved surface member 2z. The outer surface 24z corresponds to the entire outer surface of the curved surface member 2z, and the inner surface 23z corresponds to the entire inner surface of the curved surface member 2z.

[0160] The light extraction portion 241z may be provided by forming a prism portion, an uneven portion, or the like on at least a part of the outer surface 24z, or may be provided by bonding an optical functional layer to the curved surface member 2z via an adhesive (including a pressure-sensitive adhesive).

[0161] As shown in FIG. 21B, the light emitted from the light source 1 enters the inside of the wall portion 22z through the light incident end face 21z of the curved surface member 2z, and is guided inside the wall portion 22z. Inside the wall portion 22z, the light is guided while repeating total reflection on the inner surface 23z and the outer surface 24z respectively.

[0162] The light extraction portion 241z can reflect, scatter, refract or diffract a part of the light guided inside the wall portion 22z toward the inner surface 23z, and emit it from the inside of the wall portion 22z to the outside through the light emission portion 231z.

[0163] Thus, even in a configuration including the curved surface member 2z which is a hemispherical member, the same effects as those of the first embodiment can be obtained. Also, by making it hemispherical, light with substantially uniform brightness can be used to illuminate a wide range of the space. Further, since the inside of the curved surface member 2z is not open to the outside, it is possible to prevent dust and dirt from entering the inside of the curved surface member 2z without providing the lid member 4 etc. shown in FIGS. 14A and 14B. Other effects are the same as those described in the first embodiment.

[0164] Also, by applying the second embodiment to the lighting device 100z, the same effects as those of the second embodiment can be obtained. Also, not only the light extraction portion 241, but also the light extraction portions 241a to 241n can all be applied to the lighting device 100z. However, it is preferable that the optical functional layer in the light extraction portion 241z is formed in a shape along the shape of the outer surface 24z or the inner surface 23z of the curved surface member 2z.

[0165] <Modifications of the Sixth Embodiment> Here, the curved surface member included in the lighting device according to the embodiment is not limited to a hemispherical member, and any member that is a part of a hollow sphere or a rotating ellipsoid may be used. Hereinafter, various modifications of the lighting device having a curved surface member will be described.

[0166] (First and Second Modifications) Figs. 22A and 22B are perspective views for explaining the configuration of the lighting device according to the modification of the sixth embodiment, Fig. 22A shows the first modification, and Fig. 22B shows the second modification.

[0167] As shown in Fig. 22A, the lighting device 100A has a light guide part 300A. The light guide part 300A has a curved surface member 2A. The curved surface member 2A is a part of a hollow rotating ellipsoid obtained by rotating an ellipse with the X-axis as the major axis around the X-axis.

[0168] Also, as shown in Fig. 22B, the lighting device 100B has a light guide part 300B. The light guide part 300B has a curved surface member 2B. The curved surface member 2B is a part of a hollow rotating ellipsoid obtained by rotating an ellipse with the Z-axis as the major axis around the Z-axis.

[0169] The lighting device 100A is the same as the lighting device 100z except that the curved surface member 2A is a part of a hollow rotating ellipsoid obtained by rotating an ellipse with the X-axis as the major axis around the X-axis. Also, the lighting device 100B is the same as the lighting device 100z except that the curved surface member 2B is a part of a hollow rotating ellipsoid obtained by rotating an ellipse with the Z-axis as the major axis around the Z-axis. Therefore, duplicate explanations are omitted here.

[0170] (Third Modification) Next, Figs. 23A and 23B are diagrams for explaining an example of the configuration of the lighting device 100D according to the third modification of the sixth embodiment, Fig. 23A is a top view, and Fig. 23B is a cross-sectional view taken along the line I-I' of Fig. 23A.

[0171] As shown in Figs. 23A and 23B, the lighting device 100D has a light guide part 300D. The light guide part 300D has a curved surface member 2D. The curved surface member 2D is a part corresponding to approximately 1 / 4 of a hollow sphere.

[0172] A light extraction part 241D is provided on the outer surface 24D of the curved surface member 2D. The outer surface 24D corresponds to the entire outer surface of the curved surface member 2D, and the inner surface 23D corresponds to the entire inner surface of the curved surface member 2D.

[0173] Further, the light extraction unit 241D may be provided by forming a prism portion, an uneven portion, or the like on at least a part of the outer surface 24D, or may be provided by bonding an optical functional layer to the curved surface member 2D via an adhesive (including a pressure-sensitive adhesive).

[0174] The light emitted from the light source 1 enters the inside of the wall portion 22D through the light incident end face 21D in the curved surface member 2D and is guided inside the wall portion 22D. Inside the wall portion 22D, the light is guided while repeatedly undergoing total reflection at the inner surface 23D and the outer surface 24D, respectively.

[0175] The light extraction unit 241D can reflect, scatter, refract, or diffract a part of the light guided inside the wall portion 22D in the curved surface member 2D toward the inner surface 23D and emit the light from the inside of the wall portion 22D to the outside through the light emission unit 231D.

[0176] Thus, even in a configuration including the curved surface member 2D, which corresponds to approximately 1 / 4 of a hollow sphere, the same effects as those of the lighting device 100z according to the sixth embodiment can be obtained. However, in the configurations of FIGS. 23A and 23B, since the lighting device 100D cannot illuminate light in the positive X-axis direction, the lighting direction is restricted compared to the lighting device 100z, but still, light can be illuminated from various directions corresponding to 180 degrees of azimuth.

[0177] Note that the second embodiment can also be applied to the lighting device 100D to obtain the same effects as those of the second embodiment. Further, not only the light extraction unit 241 but also the light extraction units 241a to 241n can all be applied to the lighting device 100D. However, it is preferable that the optical functional layer in the light extraction unit 241D is formed in a shape along the shape of the outer surface 24D or the inner surface 23D of the curved surface member 2D.

[0178] (Fourth Modification Example) Next, FIGS. 24A and 24B are diagrams for explaining an example of the configuration of a lighting device 100E according to a fourth modification example of the sixth embodiment. FIG. 24A is a top view, and FIG. 24B is a cross-sectional view taken along the line J-J' of FIG. 24A.

[0179] As shown in FIGS. 24A and 24B, the lighting device 100E has a light guide portion 300E. The light guide portion 300E has a curved surface member 2E. The curved surface member 2E is a portion corresponding to more than half of a hollow sphere.

[0180] In addition, a light extraction portion 241E is provided on the outer surface 24E of the curved surface member 2E. The outer surface 24E corresponds to the entire outer surface of the curved surface member 2E, and the inner surface 23E corresponds to the entire inner surface of the curved surface member 2E.

[0181] The light extraction portion 241E may be provided by forming a prism portion, an uneven portion, or the like on at least a part of the outer surface 24E, or may be provided by bonding an optical functional layer to the curved surface member 2E via an adhesive (including a pressure-sensitive adhesive).

[0182] The light emitted from the light source 1 enters the inside of the wall portion 22E through the light incident end face 21E in the curved surface member 2E and is guided inside the wall portion 22E. Inside the wall portion 22E, the light is guided while repeatedly undergoing total reflection at the inner surface 23E and the outer surface 24E respectively.

[0183] The light extraction portion 241E can reflect, scatter, refract, or diffract the light guided inside the wall portion 22E in the curved surface member 2E toward the inner surface 23E, and emit the light from the inside of the wall portion 22E to the outside through the light emission portion 231E.

[0184] In this way, even in a configuration including the curved surface member 2E that is a portion corresponding to more than half of a hollow sphere, the same effects as those of the lighting device 100z according to the sixth embodiment can be obtained. Note that the second embodiment can be applied to the lighting device 100D to obtain the same effects as those of the second embodiment. Also, not only the light extraction portion 241 but also the light extraction portions 241a to 241n can all be applied to the lighting device 100E. However, it is preferable that the optical functional layer in the light extraction portion 241E is formed in a shape along the shape of the outer surface 24E or the inner surface 23E of the curved surface member 2E.

[0185] [Seventh Embodiment] Next, referring to FIG. 25, the lighting device 100F according to the seventh embodiment will be described. The lighting device 100F is a lighting device that can be installed on a side wall or the like inside a building.

[0186] FIG. 25 is a cross-sectional view for explaining an example of the configuration of the lighting device 100F. FIG. 25 corresponds to a view obtained by rotating the configuration of FIG. 2B, which is a cross-sectional view taken along the line A-A' in FIG. 2A, 90 degrees clockwise.

[0187] As shown in FIG. 25, the lighting device 100F has the same components as the lighting device 100 shown in the first embodiment. In the lighting device 100F, each component included in the lighting device 100 is rotated 90 degrees clockwise as a whole, and the base portion 3 including the light source 1 is fixed to the side wall 301.

[0188] The light emitted from the light source 1 enters the wall portion 22 in the cylindrical member 2 through the light incident end face 21, and is guided through the wall portion 22 while repeating total reflection on the inner surface 23 and the outer surface 24.

[0189] A part of the light guided through the inside of the wall portion 22 is reflected, scattered, refracted, or diffracted by the light extraction portion 241 toward the inside of the cylindrical member 2, and is emitted from the inside of the wall portion 22 to the outside through the light emission portion 231.

[0190] The lighting device 100F fixed to the side wall 301 can illuminate the inside of the lighting device 100F with the emitted light 232 emitted from the light emission portion 231. Note that the installation location of the lighting device 100F is not limited to the side wall inside the building, and the lighting device 100F may be installed on the side wall outside the building. Further, the lighting device 100F may be fixed to the side wall 301 such that the base portion 3 is embedded inside the side wall 301.

[0191] Also, in this embodiment, a configuration in which the lighting device 100F has the light guide portion 300 is illustrated, but the present invention is not limited thereto. The lighting device 100F can also have any one of the light guide portions 300a to 300E instead of the light guide portion 300.

[0192] [Eighth embodiment] Next, an illumination device 100G according to an eighth embodiment will be described with reference to Fig. 26. The illumination device 100G is an illumination device that can be installed on a ceiling or the like inside a building.

[0193] Fig. 26 is a cross-sectional view illustrating an example of the configuration of lighting device 100G. Fig. 26 corresponds to a view obtained by rotating the configuration of Fig. 2B, which is a cross-section taken along the line AA' in Fig. 2A, by 180 degrees clockwise.

[0194] 26, the lighting device 100G has the same components as the lighting device 100 shown in the first embodiment. In the lighting device 100G, the components included in the lighting device 100 are arranged rotated 180 degrees clockwise as a whole, and the base unit 3 including the light source 1 is fixed to the ceiling 302.

[0195] Light emitted from the light source 1 passes through the light incident end face 21 and enters the wall portion 22 of the cylindrical member 2, and is guided within the wall portion 22 while repeatedly being totally reflected by the inner surface 23 and the outer surface 24.

[0196] A portion of the light guided inside the wall portion 22 is reflected, scattered, refracted or diffracted by the light extraction portion 241 toward the inside of the tubular member 2, and is emitted from the inside of the wall portion 22 toward the outside through the light exit portion 231.

[0197] Illumination device 100G fixed to ceiling 302 can illuminate the inside of illumination device 100G with emitted light 232 emitted from light emitting portion 231. Note that illumination device 100G may be fixed to ceiling 302 with base portion 3 embedded inside ceiling 302.

[0198] In addition, although the present embodiment has exemplified a configuration in which lighting device 100G includes light-guiding unit 300, the present invention is not limited to this. Lighting device 100G may include any one of light-guiding units 300a to 300E instead of light-guiding unit 300.

[0199] As described above, the preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention.

[0200] Note that the curved surface member according to the embodiment may have any shape as long as it is a part of a hollow sphere or a rotating ellipsoid. However, if the curved surface member and the installation surface are configured to form a sealed space, it is possible to prevent dust and dirt from entering the sealed space, which is more preferable.

[0201] This application claims priority based on Japanese Patent Application No. 2020-194607 filed with the Japan Patent Office on November 24, 2020, and includes all the contents of this Japanese patent application.

Explanation of Reference Numerals

[0202] 1 Light source 11 LED 12 Drive circuit 2, 2d, 2e, 2p, 2q, 2r, 2u, 2v, 2w, 2y Cylindrical member 2z, 2A, 2B, 2D, 2E Curved surface member 20 Cylindrical axis 20p, 20q, 20r Central axis 201 First cylindrical member 202 Second cylindrical member 21, 21u, 21v, 21w, 21y, 21z, 21D, 21E Light incident end face 22, 22u, 22v, 22w, 22y, 22z, 22D, 22E Wall portion 23, 23u, 23v, 23w, 23y, 23z, 23D, 23E Inner surface 231, 231u, 231v, 231w, 231y, 231z, 231D, 231E Light emitting portion 232 Emitted light 24, 24u, 24v, 24w, 24y, 24z, 24D, 24E Outer surface 241, 241u, 241v, 241w, 241y, 241z, 241D, 241E Light extraction portion 232 Exit light 242, 246 Optical cavity (an example of a gap part) 243, 245, 249, 251 Optical functional layers 2431 First film 2432 Second film 244, 247 Light scattering particles (an example of a light scatterer) 248, 252 Prism parts 250, 253 Concave-convex parts 25 End face 26 Tip part 3 Base part 3z Installation surface 31 Groove part 32 Mounting surface 34 Low refractive index layer 35 Cover layer 4 Cover member 100, 100p, 100q, 100r, 100s, 100t, 100u, 100v, 100w, 100y, 100z, 100A, 100B, 100D, 100E, 100F, 100G Lighting device 300, 300a, 300b, 300c, 300d, 300e, 300f, 300g, 300h, 300i, 300j, 300k, 300m, 300n, 300p, 300q, 300r, 300s, 300t, 300u, 300v, 300w, 300y, 300z, 300A, 300B, 300D, 300E Light guide part 301 Side wall 302 Ceiling X X-axis direction (width direction) Y Y-axis direction (depth direction) Z Z-axis direction (height direction)

Claims

1. A light source, and a light guide unit that is transparent to visible light and guides the light emitted from the light source. The light guide unit has a cylindrical member and a light extraction unit that extracts the light guided through the inside of the wall portion of the cylindrical member and emits the light from the inside of the wall portion. The cylindrical member has a light incident end face that is provided on either the bottom or the top of the cylindrical member facing the light source and through which the light enters the inside of the wall portion, and a light emission portion that is included in the inner surface of the cylindrical member intersecting the light incident end face and from which the light is emitted from the inside of the wall portion. The light emitted from the inside of the wall portion in the cylindrical member is an illumination device that illuminates the space inside the cylindrical member.

2. The illumination device according to claim 1, wherein the cylindrical member is a cylindrical member.

3. The illumination device according to claim 1 or 2, wherein the cylindrical member is a member formed by winding a plate-shaped member into a cylindrical shape.

4. The illumination device according to any one of claims 1 to 3, wherein the cylindrical member is formed in either a tapered shape that becomes thinner as it moves away from the light incident end face or a tapered shape that becomes thinner as it approaches the light incident end face.

5. The light guide unit has the cylindrical member and a lid member disposed on an end face of the cylindrical member opposite to the light incident end face. The illumination device according to any one of claims 1 to 4.

6. The illumination device according to claim 4, wherein the cylindrical member has a conical shape in which the tip portions of a tapered shape that becomes thinner as it moves away from the light incident end face are connected.

7. The light guide unit has a low refractive index layer having a lower refractive index than the cylindrical member, and the low refractive index layer is provided on at least a part of at least one of the outer surface or the inner surface of the cylindrical member intersecting the light incident end face. The illumination device according to any one of claims 1 to 6.

8. The light extraction unit has an optical function layer that includes at least one of a void portion or a light scattering body inside, and the optical function layer is provided on at least a part of at least one of the outer surface or the inner surface of the cylindrical member intersecting the light incident end face. The illumination device according to any one of claims 1 to 7.

9. The light extraction unit has an optical function layer that includes at least one of a prism portion or a concavo-convex portion on the surface, The lighting device according to any one of claims 1 to 7, wherein the optical function layer is provided on at least a part of at least one of the outer surface or the inner surface of the cylindrical member that intersects the light incident end face.

10. The lighting device according to any one of claims 1 to 7, wherein the light extraction part has at least one of a prism part or a concavo-convex part provided on at least a part of at least one of the outer surface or the inner surface of the cylindrical member that intersects the light incident end face.

11. The cylindrical member has translucency to visible light, The lighting device according to any one of claims 1 to 10, wherein the space inside the cylindrical member is visible through from the outside of the cylindrical member.

12. A light source, A light guide part having translucency to visible light and guiding the light emitted from the light source, and The light guide part includes A curved surface member that is a part of a hollow sphere or an ellipsoid of revolution, and A light extraction part that emits the light guided through the inside of the wall part of the curved surface member from the inside of the wall part, and The curved surface member includes A light incident end face provided at the bottom of the curved surface member facing the light source, where the light enters the inside of the wall part, and A light emission part included in the inner surface of the curved surface member that intersects the light incident end face, and the light emits from the inside of the wall part, and The lighting device in which the light emitted from the inside of the wall part of the curved surface member illuminates the space inside the curved surface member.

13. The lighting device according to claim 12, wherein the curved surface member and the installation surface of the curved surface member form a sealed space.

14. The lighting device according to claim 12 or 13, wherein the curved surface member is a hollow hemispherical member.

15. The light guide part has a low refractive index layer having a lower refractive index than the curved surface member, The lighting device according to any one of claims 12 to 14, wherein the low refractive index layer is provided on at least a part of at least one of the outer surface or the inner surface of the curved surface member that intersects the light incident end face.

16. The light extraction part has an optical function layer including at least one of a void part or a light scattering body inside, The lighting device according to any one of claims 12 to 15, wherein the optical function layer is provided on at least one of the outer surface or the inner surface of the curved surface member that intersects the light incident end face.

17. The light extraction part has an optical function layer including at least one of a prism part or a concavo-convex part on the surface, The lighting device according to any one of claims 12 to 15, wherein the optical functional layer is provided on at least a part of at least one of the outer surface or the inner surface of the curved member that intersects the light incident end face.

18. The lighting device according to any one of claims 12 to 15, wherein the light extraction part has at least one of a prism part or an uneven part provided on at least a part of at least one of the outer surface or the inner surface of the curved member that intersects the light incident end face.

19. The curved member has translucency with respect to visible light, The lighting device according to any one of claims 12 to 18, wherein the space inside the curved member is visible through from the outside of the curved member.

20. The lighting device according to any one of claims 1 to 19, wherein the light extraction part has at least one of a void part or light scattering particles provided in at least a part of the inside of the wall part.

Images