Lighting equipment

Abstract

The lighting device (1) is a device for simulating the sky, comprising: a light source (10) that emits a first light; a light-emitting portion (20) that receives the first light, guides the incident first light by total reflection, and scatters the first light so that it is emitted from a light emitting surface; a back reflector (30) that is disposed opposite to the back surface of the light-emitting portion (20) and reflects the light emitted from the back surface of the light-emitting portion (20); a frame (40) that includes a portion located at least in front of the light emitting surface of the light-emitting portion (20); and an optical component (50) that is disposed between the light emitting surface of the light-emitting portion (20) and a portion of the frame (40) and reflects a portion of the light emitted from the light emitting surface of the light-emitting portion (20).

Description

Technical Field

[0001] The invention relates to a lighting device. Background Art

[0002] Patent document 1 proposes a lighting device for reproducing a virtual sky. The lighting device comprises a reflective layer, a light-transmitting light diffusion layer disposed on the front surface side of the reflective layer, a light-transmitting scattering panel disposed on the front surface side of the light diffusion layer, a light source disposed between the light diffusion layer and the scattering panel, and a housing for storing them. The housing comprises a frame as a frame body near the outer peripheral end of the scattering panel. The light emitted from the light source is emitted from the front surface of the scattering panel, i.e., the light exiting surface, through the central opening of the frame, after, for example, the light is diffused and transmitted at the light diffusion layer, the light is reflected at the reflective layer, and the light is reflected, scattered, and transmitted at the scattering panel.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-60624 Summary of the invention

[0006] Problems to be solved by the invention

[0007] Generally speaking, the scattered light generated inside the scatterer has no directivity and is directed in all directions. In the lighting device, in order to extract such scattered light directed in all directions from the light emitting surface, a reflector or the like is provided on the surface opposite to the light emitting surface, i.e., the back side, to improve the light utilization efficiency. However, in such a structure having a reflector on the back side of the light emitting surface of the diffuser, when there is a frame component with high reflectivity in front of the light emitting surface, etc., there is a problem that a bright spot (i.e., an area with higher brightness than other areas) is generated on the back side of the diffuser, especially near the area on the opposite side where the frame component is located. On the other hand, when there is a frame component with high absorptivity in front of the light emitting surface, there is a problem that a dark spot (i.e., an area with lower brightness than other areas) is generated on the back side of the diffuser, especially near the area on the opposite side where the frame component is located.

[0008] In addition, the lighting device described in Patent Document 1 also has a reflective layer. For example, when the component holding the diffuser plate is formed using a component with high reflectivity such as metal, it is considered that the same problem as above will occur. However, Patent Document 1 does not disclose the reflectivity of the component holding the diffuser plate at all.

[0009] When there is an unnatural brightness distribution in the scattering plate such as bright spots or dark spots caused by the frame parts, even if a virtual sky is reproduced, it is difficult to see it as a natural sky. Therefore, a means to solve the above problem is desired. In addition, it is not limited to lighting devices that simulate the sky. It is considered that unnatural light emission from the light-emitting part due to the unnatural brightness distribution caused by the frame parts also occurs in lighting devices that perform uniform lighting.

[0010] The present invention is made to solve the above-mentioned problem, and an object of the present invention is to provide a lighting device that can suppress unnatural brightness distribution of a light-emitting portion caused by a frame provided in front of the light-emitting portion and achieve more natural light-emission.

[0011] Means for solving problems

[0012] A lighting device according to one embodiment of the present invention is a device for simulating the sky, characterized in that the lighting device comprises: a light source that emits a first light; a light-emitting portion that receives the first light, guides the incident first light by total reflection, and scatters the first light to be emitted from a light emitting surface; a back reflector that is disposed opposite to the back surface of the light-emitting portion, and reflects light emitted from the back surface of the light-emitting portion; a frame that includes a portion located at least in front of the light emitting surface of the light-emitting portion; and an optical component that is disposed between the light emitting surface of the light-emitting portion and the portion of the frame, and reflects a portion of light emitted from the light emitting surface of the light-emitting portion.

[0013] Effects of the Invention

[0014] According to the present invention, it is possible to suppress unnatural brightness distribution of the light emitting unit caused by the frame provided in front of the light emitting unit, thereby achieving more natural light emission. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a cross-sectional view schematically showing the structure of the lighting device according to Embodiment 1 of the present invention.

[0016] Figure 2 This is an enlarged cross-sectional view schematically showing the structure of a main part of the lighting device according to Embodiment 1.

[0017] Figure 3 This is an exploded perspective view schematically showing a reflecting member, a light emitting unit, a light source, and an optical member of the lighting device according to Embodiment 1.

[0018] Figure 4 This is a bottom view schematically showing the structure of the lighting device according to Embodiment 1.

[0019] Figure 5 This is a functional block diagram schematically showing the configuration of a control system for the lighting device according to the first embodiment.

[0020] Figure 6 This is a cross-sectional view schematically showing the structure of a lighting device according to a modified example of Embodiment 1.

[0021] Figure 7 This is an enlarged cross-sectional view schematically showing the structure of a main part of a lighting device according to a modified example of Embodiment 1.

[0022] Figure 8 This is an enlarged cross-sectional view schematically showing the structure of a main part of a lighting device according to Embodiment 2 of the present invention.

[0023] Fig. 9 This is a bottom view showing an example of a bright area and a dark area of ​​a frame of the lighting device according to Embodiment 2.

[0024] Fig.10 This is a bottom view showing another example of the bright area and the dark area of ​​the frame of the lighting device according to the second embodiment.

[0025] Fig.11 This is a functional block diagram schematically showing the configuration of a control system for a lighting device according to the second embodiment. DETAILED DESCRIPTION

[0026] Hereinafter, the lighting device of the embodiment of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same or similar structural elements are marked with the same reference numerals. In addition, the size and scale of the structural elements shown in the drawings are different according to each drawing. The following embodiments are merely examples and various changes can be made within the scope of the present invention.

[0027] The coordinate axes of the XYZ rectangular coordinate system are shown in the accompanying drawings. The Z axis is a coordinate axis in a direction perpendicular to the light emitting surface, i.e., the front surface, of the light emitting portion of the lighting device. In the accompanying drawings, a light emitting panel is shown as the light emitting portion. The X axis and the Y axis are coordinate axes in a direction perpendicular to the Z axis. When the lighting device is installed on the ceiling, the +Z axis direction is the vertical downward direction, the -Z axis direction is the vertical upward direction, and the X axis direction and the Y axis direction are horizontal directions.

[0028] 《1》Implementation Method 1

[0029] <Lighting device 1>

[0030] Figure 1 This is a cross-sectional view schematically showing the structure of the lighting device 1 according to the first embodiment. Figure 2 It is an enlarged cross-sectional view schematically showing the structure of a main part of the lighting device 1 . Figure 3It is an exploded perspective view schematically showing the reflecting member 30 , the light emitting unit 20 , the light source 10 , and the optical member 50 of the lighting device 1 . Figure 4 1 is a bottom view schematically showing the structure of the lighting device 1. As shown in the figure, the lighting device 1 includes a light source 10, a light emitting unit 20, a reflecting member 30, a frame 40, and an optical member 50.

[0031] <Light Source 10>

[0032] The light source 10 emits light L10. The light source 10 is also referred to as the "first light source". The light source 10, for example, emits light L10 toward the light emitting unit 20. However, a light guide, a mirror, or other components for guiding the light L10 may be provided between the light source 10 and the light emitting unit 20. The light source 10 is, for example, configured so as to face the side 23 of the light emitting unit 20. The side 23 is also referred to as an "end". The light source 10 is, for example, a light emitting element array having a plurality of light emitting elements 11 arranged in a linear shape. The light emitting elements are, for example, light emitting diodes (LEDs). The plurality of light emitting elements 11 may also be arranged in two or more rows. In addition, the light source 10 is not limited to a light emitting element array, but may also be a long lamp light source, etc. Figure 3 Although four light sources 10 are shown in the figure, the number of the light sources 10 may be less than three or more than five.

[0033] <Light Emitting Unit 20>

[0034] The light emitting unit 20 receives incident light L10 as the first light, guides the incident light by total reflection, scatters the light and emits it from the light emitting surface. The light emitting unit 20 is, for example, a plate-shaped light-guiding component, having a front surface 21, a back surface 22 on the opposite side of the front surface 21, and a side surface 23 connecting the front surface 21 and the back surface 22. The front surface 21 is the surface on the observer side. The front surface 21 is also called the "light emitting surface" or the "first surface". The back surface 22 is also called the "second surface" or the "back surface". However, the shape of the light emitting unit 20 is not limited to a plate shape, and may also be other shapes such as a rod shape.

[0035] The light emitting unit 20 is formed of, for example, a light-transmitting substrate 25 and particles 24 dispersed in the substrate 25. The substrate 25 is, for example, a plate-shaped member. The particles 24 are particles that scatter light, and are also called scattering materials. The particles 24 scatter light traveling in the substrate 25.

[0036] As an example, the particle 24 is a nanoparticle. A "nanoparticle" is a particle having a size of nanometers (nm). Generally, a nanoparticle refers to a particle having a size of 1 nm to several hundred nm (eg, 300 nm). The particle 24 is a particle having a particle diameter of nanometers, for example.

[0037] Particles 24 can take the form of spherical or other shapes.

[0038] The light emitting section 20 may include a plurality of types of particles 24. In this case, the particle diameter of the particles 24 may be an average particle diameter.

[0039] The particles 24 are, for example, inorganic oxides, such as ZnO, TiO2, ZrO2, SiO2, and Al2O3.

[0040] The base material 25 may include, for example, the particles 24. In addition, the particles 24 may be added to the base material 25. The particles 24 are dispersed in the base material 25, for example.

[0041] The material of the substrate 25 is not particularly limited, but is, for example, a transparent material. The substrate 25 does not need to be transparent to all wavelengths of incident light. For example, the substrate 25 may absorb a specific wavelength among the wavelengths of incident light.

[0042] The transmittance (i.e., direct transmittance) of the substrate 25 at a light guide distance of 5 mm is preferably 90% or more, more preferably 95% or more, and further preferably 98% or more at the design wavelength. Here, the design wavelength is a predetermined wavelength among the wavelengths of the incident light. The design wavelength is not limited to one wavelength, but may also be multiple wavelengths or a wavelength with a width (i.e., a band). For example, when the incident light is white light, the design wavelength may be one or more of 450nm, 550nm, and 650nm. In addition, the design wavelength may also be three wavelengths of 450nm, 550nm, and 650nm.

[0043] The substrate 25 is, for example, a solid. The substrate 25 may be, for example, a resin plate using a thermoplastic polymer, a thermosetting resin, or a photopolymerizable resin. In addition, as the resin plate, acrylic polymers, olefin polymers, vinyl polymers, cellulose polymers, amide polymers, fluorine polymers, urethane polymers, silicone polymers, or imide polymers may be used. For example, the particles 24 may be dispersed in the material before curing of the substrate 25, and then the curing treatment may be performed to form the light emitting portion 20.

[0044] In addition, the light-emitting portion 20 may also be formed of a porous material, an organic molecule dispersed material, an organic-inorganic hybrid material (also referred to as an organic-inorganic nanocomposite material) or a metal particle dispersed material made by a sol-gel method. As an example, the light-emitting portion 20 may be an organic / inorganic hybrid resin, for example, a mixed resin of a resin and an inorganic oxide. In this case, the light-emitting portion 20 has an inorganic oxide as a substance equivalent to the particle 24, and the inorganic oxide is generated by sol-gel curing using a material containing an inorganic oxide and a substrate 25 of an organic compound as a basis. In addition, in the present application, fine pores generated by such a manufacturing process are also regarded as particles 24.

[0045] In addition, the light-emitting section 20 may also have fine concave and convex portions smaller than the wavelength of blue light formed on the surface of the substrate 25. In this case, the light-emitting section 20 has fine concave or convex portions formed on the surface of the substrate 25 as particles 24. At this time, it is preferred that the maximum diameter of the concave or convex portion is nanometer-level (e.g., 1 nm to several hundred nm in size).

[0046] In addition, the particles 24 and the base material 25 may not be clearly distinguished as different components in the light emitting section 20. In addition, the base material 25 is not limited to a solid, and may be a liquid, liquid crystal, or a gel-like substance.

[0047] like Figure 1 and Figure 2 As shown, the light incident from the side surface 23 of the light emitting portion 20 is totally reflected at the front surface 21 and the back surface 22, thereby being guided. The totally reflected light is indicated by reference numeral L11. In addition, a portion of the light incident from the side surface 23 is scattered by the particles 24. The light generated by the scattering is indicated by reference numeral L12. In addition, the light emitting portion 20 may also have a structure formed by stacking a plurality of light-transmitting components.

[0048] Light incident into the light emitting portion 20 from the side surface 23 is guided, scattered, and emitted from the front surface 21 or the back surface 22. The haze value of the light emitting portion 20 in the thickness direction (i.e., the Z-axis direction) of the light emitting portion 20 is preferably in the range of 0.005% to 30%. The haze value of the light emitting portion 20 is more preferably in the range of 0.1% to 15%, and further preferably in the range of 0.5% to 5%.

[0049] The reason for specifying the upper limit of the haze value in the Z-axis direction of the light emitting unit 20 is that, when the haze value is sufficiently high, the bright spot of the reflective member 30 generated by the reflection of light in the optical member 50, that is, the high brightness area 31 is difficult to be recognized by the observer. That is, when the haze value is sufficiently high, the blurring degree of the light emitting unit 20 is high, so even if the high brightness area 31 is generated on the back surface 22 side of the light emitting unit 20, the observer on the front surface 21 side of the light emitting unit 20 will not recognize the uneven brightness on the front surface 21. In other words, this is because, when the haze value is sufficiently high, the reflectivity of the optical member 50 has almost no effect on the state of the front surface 21 of the light emitting unit 20 of the lighting device 1 observed by the observer.

[0050] <Reflection member 30>

[0051] The reflective component 30 is disposed opposite to the surface on the opposite side of the light emitting surface of the light emitting portion 20, i.e., the back surface, and reflects the light emitted from the back surface of the light emitting portion 20. The reflective component 30 is also called a back reflective portion. There is a space, i.e., an air layer, between the reflective component 30 and the back surface 22 of the light emitting portion 20. This is to cause total reflection at the back surface 22 of the light emitting portion 20. The reflective component 30 reflects the light emitted from the back surface 22 of the light emitting portion 20 that does not meet the total reflection condition toward the back surface 22, i.e., returns to the light emitting portion 20 from the back surface 22. The reflective component 30 has the characteristic of reflecting light. The reflective component 30 is, for example, a component having a white reflective surface. The reflective component 30 is, for example, a thin film, a plate-shaped metal, i.e., a sheet metal or a plastic plate. The reflective surface of the reflective component 30 may also be a diffuse reflective surface. The diffuse reflective surface may be formed, for example, by white painting.

[0052] <Frame 40>

[0053] The frame 40 includes a portion located at least in front (i.e., in the +Z axis direction) of the light emitting surface (in this example, the front surface 21 in the figure) of the light emitting unit 20. The frame 40, for example, has the portion facing the first area in the front surface 21, and an opening 42 through which the light emitted from the second area adjacent to the first area in the front surface 21, i.e., the illumination light L14, passes. For example, the first area is an area on the outer peripheral side, and the second area is an area near the center. In addition, the first area and the second area in the front surface 21 of the light emitting unit 20 are names for convenience, and there is no physical boundary between the first area and the second area. In addition, it is not limited to the above example. Furthermore, the frame 40 does not necessarily have to have an opening (in this case, it means an area surrounded by certain components all around it), for example, it can also be a structure in which two or more portions are arranged side by side with a specified gap. In this case, the gap can also be regarded as an opening through which the illumination light L14 passes. In other words, in the light emitting unit 20, the area in front of the frame 40 can also be regarded as the first area, and the area not in front of the frame 40 can be regarded as the second area.

[0054] The frame 40 is formed of metal, plastic, etc. The frame 40 may also be the housing of the lighting device 1 or a part thereof. The frame 40 may also be a design component that combines design and functionality. The opening 42 is a space where nothing exists or a light-transmitting component through which light can pass. Figure 1 and Figure 2 In the figure, the first region is a region including the side of the side surface 23 of the light emitting portion 20 , that is, the outer peripheral edge of the front surface 21 .

[0055] <Optical component 50>

[0056] The optical component 50 is located between the light emitting unit 20 and the frame 40, and reflects a portion of the light emitted from the front surface 21 of the light emitting unit 20 (particularly, the light emitted from the area in front of the frame 40 among the light emitted from the front surface 21). More specifically, the optical component 50 is arranged between the light emitting unit 20 and the frame 40, and in particular, on the optical path of the light emitted from the front surface 21 of the light emitting unit 20 that reaches the frame 40. In addition, the optical component 50 may also be arranged in an area where the front surface 21 of the light emitting unit 20 overlaps with the frame 40 when viewed from above. The optical component 50 may, for example, also have a surface facing the first area, namely, an upper surface 51. The upper surface 51 is also referred to as the "third surface". In addition, the optical component 50 may or may not abut the front surface 21 of the light emitting unit 20 and the frame 40. For example, the optical component 50 may also include an air layer between the light emitting unit 20, the frame 40, or both. A portion of the light emitted from the first region of the light emitting unit 20 is reflected by, for example, the upper surface 51 of the optical component 50, and enters the light emitting unit 20 from the first region. In addition, the optical component 50 is not limited to a structure that must reflect light on the upper surface 51, as long as it at least reflects the incident light. In addition, the optical component 50 does not have to reflect all the light incident on the optical component 50. In other words, the reflectivity of the optical component 50 may also be lower than 100%.

[0057] The optical component 50 is formed of, for example, paint, film, paper, or resin. In addition, the optical component 50 may be formed integrally with the frame 40. That is, the end of the frame 40 on the side of the front surface 21 of the light emitting unit 20 may also be formed by the optical component 50. As an example, the upper surface of the frame 40 (the surface constituting the end on the side of the front surface 21 of the light emitting unit 20) may also be formed by the optical component 50.

[0058] The reflectivity of the optical component 50 is in the range of 20% to 60%. The reflectivity of the optical component 50 is more preferably in the range of 45% to 55%. Here, the above reflectivity range can also be rewritten as the reflectivity of light incident from the upper surface 51 side of the optical component 50. However, the above reflectivity range can also be applied to light other than the light incident from the upper surface 51 side.

[0059] The reason for setting the upper limit of the reflectivity of the optical component 50 is that, when the reflectivity is too high, the brightness of the high-brightness area 31 of the reflective component 30 generated by the reflection of light in the optical component 50 increases, and is easily recognized as a bright spot by the observer. That is, this is because, when the reflectivity of the optical component 50 is too high, the observer located on the front surface 21 side of the light-emitting portion 20 can more strongly recognize the high-brightness area 31 that appears on the back surface 22 side of the light-emitting portion 20. This is because it is difficult for the observer who recognizes this uneven brightness to feel the natural light emission through the lighting device 1. Figure 2As shown, in Embodiment 1, the observer recognizes a bright spot in the area A1 near the frame 40 in the front surface 21 of the light emitting unit 20. In this case, the observer recognizes the presence of the reflective member 30 provided to improve light utilization efficiency, which may cause an unnatural feeling such as feeling that other areas (especially the peripheral area) are darker.

[0060] The reason for setting the lower limit of the reflectivity of the optical component 50 is that, when the reflectivity is too low, the brightness of the dark spot, i.e., the low brightness area, of the reflective component 30 generated by the reflection of light in the optical component 50 is reduced, and is easily recognized as a dark spot by the observer. That is, this is because, when the reflectivity of the optical component 50 is too low, the observer located on the front surface 21 side of the light-emitting portion 20 strongly recognizes the low brightness area appearing on the back surface 22 side of the light-emitting portion 20. As described above, it is difficult for the observer who recognizes such uneven brightness to feel the natural light emission through the lighting device 1. In embodiment 1, the observer recognizes the dark spot in the vicinity area A1 of the frame 40 in the front surface 21 of the light-emitting portion 20. In this case, the observer recognizes the presence of the reflective component 30 provided to improve the light utilization efficiency, which may cause an unnatural feeling such as feeling that other areas (especially the peripheral areas) are brighter.

[0061] The brightness of each position on the front surface 21 of the light emitting unit 20 recognized by the observer on the front surface 21 side of the lighting device 1 is determined by the amount of light emitted from each position. The light emitted from the front surface 21 of the light emitting unit 20 includes, for example, the following light (L1) to (L4).

[0062] (L1) Light that is directed toward the front surface 21 among scattered lights generated in the light emitting section 20 .

[0063] (L2) Of the scattered light generated in the light emitting unit 20 , light that is emitted from the rear surface 22 , reflected by the reflecting member 30 , and travels toward the front surface 21 .

[0064] (L3) Light that enters the light emitting section 20 from the side surface 23 and enters the front surface 21 at an angle that does not satisfy the total reflection condition.

[0065] (L4) Return light from outside The return light from outside is light emitted from the lighting device 1 that is reflected by the wall or floor of the room, enters the light emitting unit 20 from the front surface 21 , and is reflected by the reflective member 30 toward the front surface 21 .

[0066] Various lights such as (L1) to (L4) are emitted from the light emitting unit 20. Therefore, when there is a component with high reflectivity (e.g., a metal frame) in front of the front surface 21, the light emitted from the front surface 21 is reflected by the frame 40 and reaches the reflective component 30, which may generate a high brightness area 31. In addition, when there is a component with low reflectivity in front of the front surface 21, the shadow of the component with low reflectivity reaches the reflective component 30, which may generate a low brightness area. In order to prevent the generation of these bright spots and dark spots, it is preferable to set the reflectivity of the optical component 50 within the above-mentioned reflectivity range. The reflectivity of the optical component 50 is, for example, the reflectivity of light incident from the upper surface side of the optical component 50.

[0067] <Control System>

[0068] Figure 5 1 is a functional block diagram schematically showing the structure of the control system of the lighting device 1. Figure 5 As shown, the lighting device 1 includes, for example, a driving circuit that turns on, dims, or turns off the light source 10, namely, a light source driving unit 12, and a control circuit that controls the light source driving unit 12, namely, a lighting control device 13. The lighting control device 13 may also include a memory that stores a program and a processor that executes the program. The lighting control device 13 may control the lighting, dimming, and turning off of the light source 10 in a manner that has a certain correlation according to time, climate, and season. Dimming may also include adjusting the intensity of light and adjusting the color of light.

[0069] <Effect>

[0070] As described above, by using the lighting device 1, it is possible to suppress the unnatural brightness distribution of the light emitting unit 20 caused by the frame 40 provided in front of the light emitting unit, and realize more natural light emission. That is, by using the lighting device 1, it is possible to realize light emission that does not cause an unnatural feeling to the observer, that is, the observer does not feel unnatural light emission. For example, the observer can feel a window simulating incident natural light through the lighting device 1. That is, the observer can feel that a virtual sky is reproduced through the lighting device 1.

[0071] <Modification>

[0072] Figure 6 This is a cross-sectional view schematically showing the structure of a lighting device 1 a according to a modified example of Embodiment 1. Figure 7 1 is an enlarged cross-sectional view schematically showing the structure of the main part of the lighting device 1a. Figure 6 and Figure 7 , the lighting device 1a is shown to be installed on the ceiling 90. Figure 6 and Figure 7As shown, the frame may be located away from the end of the light emitting unit 20. That is, the first area of ​​the front surface 21 of the light emitting unit 20 may be an area not including the outer peripheral end of the front surface 21. According to the lighting device 1a, the structure can be simplified compared with the lighting device 1.

[0073] 《2》Implementation Method 2

[0074] <Lighting device 2>

[0075] Figure 8 2 is a cross-sectional view schematically showing the structure of the main part of the lighting device 2 according to the second embodiment. Figure 8 In, with Figure 2 Structural elements that are identical or corresponding to the structural elements shown are marked with Figure 2 The lighting device 2 of the second embodiment is different from the lighting device 1 of the first embodiment in the shape of the frame 70 and the inclusion of the light source 60. In other respects, the second embodiment is the same as the first embodiment.

[0076] <Light Source 60>

[0077] The light source 60 emits light. The light source 60 is also referred to as a "second light source". The light source 60 is disposed outside the frame 70. The light source 60 has the same structure as the light source 10. However, the light source 60 may have a structure different from that of the light source 10. In addition, instead of the light source 60, a light branching component or a light guide component may be provided to direct a portion of the light emitted by the light source 10 toward the frame 70.

[0078] <Frame 70>

[0079] The frame 70 has a wall-shaped portion 73 on the front surface 21 of the light-emitting portion 20. The frame 70 is, for example, a light-transmitting component. The frame 70 may also include a light-diffusing material that diffuses light. The frame 70 is formed in a manner to surround the space in front of the front surface 21. The frame 70 may also be inclined relative to the normal to the front surface 21 in a manner such that the space in front of the front surface 21 becomes wider as it moves away from the front surface 21. The frame 70 is composed of four faces, but the number of portions 73 constituting the frame 70 may also be other than four faces. In addition, the frame 70 may also include a curved surface. The light from the light source 60 (also referred to as the "second light") is incident on the frame 70, is transmitted and diffused, and then is emitted from the front side of the frame 70.

[0080] The optical component 50 has an upper surface 51 which is a surface facing the front surface side of the light-emitting unit 20 and a lower surface 52 which is a surface facing the frame 70 side. The lower surface 52 is also referred to as the "fourth surface". In the case where the frame 70 is a light-transmitting component, the reflectivity of the upper surface 51 is preferably set to be lower than the reflectivity of the lower surface 52. The frame 70 is made of, for example, resin, glass, or a film. The reflectivity of the lower surface 52 is preferably 70% or more. The reflectivity of the lower surface 52 is more preferably 90% or more. Here, the reflectivity of the upper surface 51 and the reflectivity of the lower surface 52 of the optical component 50 can also be rewritten as the reflectivity for light incident from the upper surface 51 side of the optical component 50 (for example, light traveling along the +Z direction in the figure) and the reflectivity for light incident from the lower surface 52 side (for example, light traveling along the -Z direction in the figure), respectively.

[0081] The light source 60 is disposed outside the frame 70 and radiates light from outside the frame 70. The light emitted by the light source 60 passes through the frame 70, or diffuses and passes through, and is emitted as light L15 to the space in front of the front surface 21. When the light emitting portion 20 simulates a window, the frame 70 can simulate a window frame.

[0082] Fig. 9 1 is a bottom view showing an example of a bright region 73 a and a dark region 73 b of the frame 70 of the lighting device 2 . Fig.10 7 is a bottom view showing another example of a bright region 73a and a dark region 73b of the frame 70. The bright region 73a is a region with high light transmittance, and the dark region 73b is a region with lower light transmittance than the bright region 73a. The observer can feel the bright region 73a and the dark region 73b like the sun and the shade formed on the window frame. That is, the observer can feel the actual sunlight, that is, natural light, as if it is emitted from the light emitting portion 20.

[0083] <Control System>

[0084] Fig.11 2 is a functional block diagram schematically showing the structure of the control system of the lighting device 2. Fig.11 In, with Figure 5 Structural elements that are identical or corresponding to the structural elements shown are marked with Figure 5 The same reference numerals are used as shown in the figure. Fig.11 As shown, the lighting device 2 includes a driving circuit, i.e., a light source driving unit 62, which turns on, dims, or turns off the light source 60, and a control circuit, i.e., a lighting control device 13, which controls the light source driving unit 62. The lighting control device 13 may also include a memory for storing a program and a processor for executing the program. The lighting control device 13 may control the lighting, dimming, and turning off of the light source 10 and the light source 60 in a manner having a certain correlation according to time, climate, and season, for example. Dimming may also include adjusting the intensity of light and adjusting the color of light.

[0085] <Effect>

[0086] As described above, by using the lighting device 2, it is possible to suppress unnatural brightness distribution of the light emitting unit 20 caused by the components provided in front of the light emitting unit 20, and realize more natural light emission. For example, the observer can feel a window simulating incident natural light through the lighting device 2. That is, the observer can feel that a virtual sky is reproduced through the lighting device 2.

[0087] 《3》Variation

[0088] The structures of the above-mentioned first embodiment, the modification of the first embodiment, and the second embodiment can be combined as appropriate.

[0089] Description of symbols

[0090] 1, 1a, 2: lighting device; 10: light source; 20: light emitting part; 21: front surface; 22: back surface; 23: side surface; 24: particle; 30: reflective component; 31: bright spot; 40: frame; 42: opening; 50: optical component; 51: upper surface; 52: lower surface; 60: light source; 70: frame; 73: part; 73a: bright area; 73b: dark area.

Claims

1. A lighting device for simulating the sky, the lighting device comprising: a light source that emits a first light; a light emitting section that receives the first light, guides the incident first light by total reflection, and scatters the first light to emit it from a light emitting surface; a back reflector disposed opposite to the back surface of the light emitting portion and reflecting light emitted from the back surface of the light emitting portion; a frame including a portion located at least in front of the light emitting surface of the light emitting portion; as well as an optical component disposed between the light emitting surface of the light emitting portion and the portion of the frame, and reflecting a portion of the light emitted from the light emitting surface of the light emitting portion, The reflectivity of the optical component is 20% to 60%.

2. The lighting device according to claim 1, in, The frame is used to simulate a window frame, and is provided at least one of an end of the light emitting portion and a periphery of the light emitting portion.

3. The lighting device according to claim 1, in, The frame includes a light-transmitting component.

4. The lighting device according to claim 2, in, The frame includes a light-transmitting component.

5. The lighting device according to any one of claims 1 to 4, in, The frame includes a wall-shaped portion of a light-transmitting member.

6. The lighting device according to any one of claims 1 to 4, in, The optical member is disposed in a region where a front surface overlaps with the frame in a plan view, the front surface being a surface of the light emitting portion having the light emitting surface.

7. The lighting device according to any one of claims 1 to 4, in, The optical component is arranged at a position away from an end of the light emitting unit.

8. The lighting device according to any one of claims 1 to 4, in, The lighting device further comprises a light source for emitting a second light. The second light is incident on the frame, and is emitted from the front surface of the frame after being transmitted and diffused.

9. The lighting device according to any one of claims 1 to 4, in, The optical member includes a first surface facing the light emitting surface side of the light emitting unit and a second surface facing the portion of the frame, and the first surface and the second surface have different reflectances.

10. The lighting device according to claim 9, in, The reflectivity of the first surface of the optical component is 20% to 60%, and the reflectivity of the second surface is 70% or more.

11. The lighting device according to any one of claims 1 to 4, in, The haze value of the light emitting portion in the thickness direction is 0.005% to 30%.

12. The lighting device according to any one of claims 1 to 4, in, The light emitting portion is a Rayleigh scatterer that generates scattered light using Rayleigh scattering.

13. The lighting device according to any one of claims 1 to 4, in, The light source is arranged opposite to the end surface of the light emitting portion.

14. The lighting device according to any one of claims 1 to 4, in, The frame is provided at at least one of an end of the light emitting portion and a periphery of the light emitting portion, and has a bright region and a dark region.

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