JP7247484B2 - lighting equipment - Google Patents

Description

The present invention relates to lighting devices.

For example, Patent Literature 1 describes a lighting device capable of reproducing a pseudo sky with a simple structure. The lighting device comprises a white light source, a blue light source, a reflective layer, a light diffusing layer and a scattering panel. The reflective layer reflects light. The light diffusion layer is provided on the surface side of the reflective layer and has translucency. The scattering panel is provided on the surface side of the light diffusion layer, arranged to face the light diffusion layer, and has translucency. The scattering panel is, for example, a Rayleigh scattering plate. At least part of the distance between the scattering panel and the reflective layer and the light diffusing layer changes from one end side to the other end side of the scattering panel. Then, the white light source and the blue light source are provided on one end side of the scattering panel, and arranged in such a posture as to irradiate the light toward the light diffusion layer and the scattering panel.

Japanese Patent Application Laid-Open No. 2018-60624

However, out of the external light that enters the interior of the illumination device from the viewer's side, the light that is not scattered by the light diffusion layer is reflected by the reflection layer and emitted from the illumination device. Then, the observer perceives the outside light emitted without being scattered as the light emitted by the illumination device. As a result, when the external light is white, the blue light emitted by the lighting device becomes whitish blue light. That is, the simulated sky color is degraded by outside light.

The lighting device is a lighting device that irradiates light that simulates the sky, and includes a light source that emits light and nanoparticles, the light is incident and guided, and is scattered light scattered by the nanoparticles. and a diffuser that emits scattered light simulating the sky from an exit surface; a first polarizing plate arranged on the front surface side of the body and transmitting light polarized in a specific direction; and a reflector arranged on the rear surface side of the diffuser and reflecting incident light. Prepare.

The present invention reduces deterioration of the color of light emitted by an illumination device due to external light.

1 is a configuration diagram showing the configuration of a lighting device according to Embodiment 1; FIG. 1 is a configuration diagram showing an example of a light source according to Embodiment 1; FIG. 2 is a configuration diagram showing the configuration of a diffuser according to Embodiment 1; FIG. FIG. 5 is a configuration diagram showing the configuration of Modification 1 according to Embodiment 1; FIG. 10 is a configuration diagram showing a configuration of Modification 2 according to Embodiment 1;

<Description of coordinates in the figure>
In each of the following embodiments, coordinate axes of an xyz orthogonal coordinate system are shown in each drawing for ease of explanation.

The z-axis is parallel to the optical axis of light source 1 . The +z-axis direction is the direction in which the light source 1 emits light. The y-axis is parallel to the direction in which lighting device 100 emits light. The y-axis is, for example, the vertical direction of the lighting device 100 . The −y-axis direction is the direction in which the illumination device 100 emits light. The x-axis is perpendicular to the yz-plane.

In the lighting device described in Prior Document 1, the light diffusion layer is arranged on the back side of the scattering panel to diffuse the light. Therefore, the light diffusion layer inside the lighting device can be seen from the observer side. The embodiments described below can reduce the visibility inside the lighting device.

Embodiment 1.
Embodiment 1 will be described below with reference to FIGS. 1 to 5. FIG. In each of the drawings below, the scale of dimensions may be changed depending on the component.

<Configuration of lighting device 100>
FIG. 1 is a configuration diagram showing a schematic configuration of a lighting device 100 according to Embodiment 1. FIG. FIG. 2 is a configuration diagram showing a schematic configuration of the light source 1 according to Embodiment 1. As shown in FIG. The configuration of lighting device 100 will be described with reference to FIGS. 1 and 2. FIG.

A lighting device 100 includes a light source 1 , a diffuser 2 , a polarizer 3 and a reflector 5 .

≪Light source 1≫
The light source 1 emits light _L1 . The light source 1 emits white light, for example. The light _L1 is, for example, white light. The light source 1 emits light _L1 with a correlated color temperature T of 6500K, for example. By "correlated color temperature" is meant the color temperature of blackbody radiation that appears closest in color to the color of the illuminant.

The light source 1 is, for example, an LED light source. The light source 1 is, for example, a white LED. The light source 1 has, for example, a plurality of LED elements 10 arranged on a substrate 11 . The color temperature of the light _L1 emitted by each LED element 10 is, for example, the same. Also, the color temperature of the light _L1 emitted by each LED element 10 may be different. The light _L1 emitted by the LED element 10 may be red, green, or blue.

The light source 1 comprises a light emitting surface 12 for emitting light _L1 . The light emitting surface 12 is arranged, for example, facing the incident surface 21 of the diffuser 2 . A plurality of light sources 1 are arranged, for example, along the incident surface 21 of the diffuser 2 .

≪Diffuser 2≫

The diffuser 2 has an entrance surface 21 , an exit surface 22 and a back surface 23 . The diffuser 2 comprises particles 24 and a substrate 25 . The diffuser 2 is, for example, plate-shaped. In the plate shape, two opposing surfaces are joined by side surfaces. Alternatively, the diffuser 2 is, for example, rod-shaped. A bar shape is a columnar shape. In the bar shape, two opposing bottom surfaces are connected at the sides.

The incident surface 21 is arranged facing the light source 1, for example. The incident surface 21 is arranged, for example, so as to face the light emitting surface 12 of the light source 1 . Light L ₁ emitted by the light source 1 is incident on the diffuser 2 through the incident surface 21 . The diffuser 2 guides the incident light _L1 .

Outgoing surface 22 emits light L ₂ scattered by particles 24 . Light _L2 is scattered light. The exit surface 22 emits the light L ₂ guided in the diffuser 2 and scattered by the particles 24 .

The exit surface 22 is formed on the −y-axis side of the diffuser 2 . The exit surface 22 is arranged parallel to the zx plane, for example. The exit surface 22 is formed, for example, on one plate-shaped surface. The output surface 22 is, for example, a bar-shaped side surface.

The rear surface 23 is arranged to face the emission surface 22 . The back surface 23 is formed on the +y-axis side of the diffuser 2 . The rear surface 23 is arranged parallel to the zx plane, for example. The back surface 23 is formed, for example, on one plate-shaped surface. The back surface 23 is, for example, a bar-shaped side surface.

The light L ₁ incident on the diffuser 2 is reflected by the exit surface 22 and the rear surface 23 and guided through the diffuser 2 . The reflection on the output surface 22 is, for example, total reflection. Reflection at the back surface 23 is, for example, total internal reflection.

The particles 24 are nano-order particles. The particle 24 is a particle with a nano-order particle size. That is, the particles 24 are nanoparticles. Particles 24 are, for example, a material that transmits light.

Particles 24 may be spherical or have another shape. The particle size of particles 24 is preferably in the range of 60 nm to 150 nm. That is, the particle size of the particles 24 is preferably 60 nm or more and 150 nm or less.

Particles 24 are, for example, an inorganic oxide. Inorganic oxides include _ZnO , _TiO2 , _ZrO2 , _SiO2 and _Al2O3 .

Substrate 25 has particles 24 dispersed therein. Particles 24 are added to substrate 25 . The base material 25 is a material that transmits light. The refractive index of substrate 25 is different from the refractive index of particles 24 .

The base material 25 is, for example, solid. The base material 25 is a solid that transmits light. The base material 25 is formed of a resin film using, for example, thermoplastic polymer, thermosetting resin, photopolymerizable resin, or the like. As the resin film, for example, an acrylic polymer, an olefin polymer, a vinyl polymer, a cellulose polymer, an amide polymer, a fluorine polymer, a urethane polymer, a silicone polymer, an imide polymer, or the like can be used. .

The base material 25 is, for example, liquid. The base material 25 is a liquid that transmits light. Substrate 25 may be, for example, water. A substrate 25 made of liquid is filled in the container. The container filled with the liquid substrate 25 is made of a light-transmitting material. The container is made of, for example, an acrylic polymer material.

The base material 25 is a gel substance. The base material 25 is a gel-like substance that transmits light. A substrate 25 made of a gel-like substance is filled in the container. The container filled with the substrate 25 made of a gel-like substance is made of a material that transmits light. The container is made of, for example, an acrylic polymer material.

<<Polarizing plate 3>>
The polarizing plate 3 transmits light polarized in a specific direction. The polarization direction of the light transmitted by the polarizing plate 3 is parallel to the plane perpendicular to the direction in which the light _L1 is guided inside the diffuser 2.

The polarizing plate 3 is arranged to face the exit surface 22 of the diffuser 2 . The polarizing plate 3 is arranged on the exit surface 22 side with respect to the diffuser 2 . The polarizing plate 3 may be sheet-like, for example. Also, the polarizing plate 3 may be, for example, in the form of a film. A film-like polarizing plate 3 is formed, for example, on the emission surface 22 of the diffuser 2 .

≪Reflector 5≫
Reflector 5 reflects light. Reflector 5 reflects light emitted from back surface 23 of diffuser 2 . The light reflected by the reflector 5 enters the diffuser 2 from the rear surface 23 . The light emitted from the rear surface 23 of the diffuser 2 is, for example, light _L2 .

The reflector 5 is arranged to face the rear surface 23 of the diffuser 2 . The reflector 5 is arranged on the rear surface 23 side with respect to the diffuser 2 . The reflector 5 may be sheet-shaped, for example. Also, the reflector 5 may be, for example, in the form of a film. The film-like reflector 5 is formed on the rear surface 23 of the diffuser 2, for example.

<Effects of lighting device 100>

<<Relationship between light _L2 and polarizing plate 3>>
3A and 3B are diagrams for explaining the principle of generating diffused light simulating a blue sky in the diffuser 2. FIG. The principle of generating diffused light simulating a blue sky will be described with reference to FIG.

As shown in FIG. 3, the light _L1 emitted from the light source 1 enters from the incident surface 21 of the diffuser 2. As shown in FIG. A portion of the light L ₁ impinges on the particles 24 . The light _L1 striking the particle 24 is scattered in all directions.

Light L ₂ that has entered the exit surface 22 at an incident angle less than or equal to the critical angle is emitted from the exit surface 22 . Similarly, the light L ₂ incident on the rear surface 23 at an incident angle equal to or less than the critical angle is emitted from the rear surface 23 . The critical angle is the smallest angle of incidence at which total internal reflection occurs when light travels from an area with a high refractive index to an area with a low refractive index.

Rayleigh scattering is the scattering of light by particles smaller than the wavelength of light. Particles smaller than the wavelength of light are, for example, nanoparticles. Shorter wavelength light is scattered more than longer wavelength light. Here, for example, light with a short wavelength is blue light. Light with a long wavelength is red light. Rayleigh scattered light is light that has been Rayleigh scattered.

Therefore, when the light _L1 has a spectral distribution in the visible light region, blue light is preferentially scattered. That is, the correlated color temperature _T2 of the light _L2 is higher than the correlated color temperature _T1 of the light _L1 . The light _L2 has a correlated color temperature _T0 close to the actual blue sky.

Also, the scattered light in the direction perpendicular to the traveling direction of the light _L1 is polarized. The degree of polarization of the scattered light in the direction perpendicular to the direction of travel of the light _L1 is high. Scattered light in a direction perpendicular to the direction of incidence of light on particles 24 is linearly polarized light. That is, the light _L2 directed toward the exit surface 22 has strong polarization characteristics. The vibration component due to the polarization of the light _L2 is large on the plane perpendicular to the direction of travel of the light. Here, the traveling direction of the light _L1 is the +z-axis direction.

On the other hand, the scattered light in the traveling direction of the light _L1 is non-polarized light. The degree of polarization of the scattered light in the traveling direction of the light _L1 is low. Non-polarized light is light that has no regularity in polarization. Unpolarized light is also called natural light.

The direction of polarized light transmitted by the polarizing plate 3 is parallel to the plane perpendicular to the direction in which the light _L1 is guided inside the diffuser 2 as described above. As a result, the polarizing plate 3 efficiently transmits the light _L2 .

<<Relationship between light _L2 and reflector 5>>
The light L ₂ incident on the rear surface 23 at an incident angle less than or equal to the critical angle is emitted from the rear surface 23 . Light L ₂ emitted from the rear surface 23 is reflected by the reflector 5 . The light L ₂ reflected by the reflector 5 enters the diffuser 2 .

If the light _L2 is specularly reflected by the reflector 5, the polarization direction of the light _L2 is preserved. Therefore, the light _L2 that is not scattered by the particles 24 as it passes through the diffuser 2 is polarized light. Light L ₂ that is not scattered by particles 24 is transmitted through polarizing plate 3 .

Also, the light L2 scattered by the particles 24 when passing through the diffuser ₂ is non-polarized light. Therefore, the light L ₂ scattered by the particles 24 and having a polarization direction different from that of the polarizing plate 3 is absorbed by the polarizing plate 3 .

When the light _L2 is diffusely reflected by the reflector 5, the polarization direction of the light _L2 is not preserved. That is, the diffusely reflected light _L2 is non-polarized light. The light L2 scattered by the particles 24 when passing through the diffuser ₂ is non-polarized light. The light _L2 that is not scattered by the particles 24 when passing through the diffuser 2 is also unpolarized light. Therefore, the light L ₂ transmitted through the diffuser 2 and having a polarization direction different from that of the polarizing plate 3 is absorbed by the polarizing plate 3 .

As described above, the visibility of the interior of the illumination device 100 for the observer is reduced. And the depth feeling of the simulated sky can be improved.

<<Relationship between outside light and polarizing plate 3>>
Next, consider a case where external light Lo ₁ is incident on the lighting device 100 from the side of the room in which the lighting device 100 is installed. The outside light Lo ₁ is, for example, light that is scattered by walls, floors, furniture, or the like from indoor sunlight. Alternatively, the external light Lo ₁ is light generated by a lighting device or the like and scattered by walls, floors, furniture, or the like.

The external light Lo ₁ is non-polarized light. Also, for ease of explanation, it is assumed that the external light Lo ₁ enters the polarizing plate 3 perpendicularly. That is, the traveling direction of the external light Lo ₁ is the +y-axis direction.

Light in the polarization direction different from the polarization direction of the polarizing plate 3 in the external light Lo ₁ is absorbed by the polarizing plate 3 . Generally, about half of the external light Lo ₁ is absorbed when passing through the polarizing plate 3 . The external light Lo ₁ that has not been absorbed enters the diffuser 2 . The unabsorbed ambient light Lo ₁ is about half of the incident ambient light Lo ₁ . That is, approximately half of the external light Lo ₁ enters the diffuser 2 .

External light Lo ₁ is scattered by particles 24 . Of the external light Lo ₁ scattered by the particles 24, the external light Lo ₂ scattered in the traveling direction is non-polarized light. The external light Lo ₁ scattered by the particles 24 is the external light Lo ₂ . The external light _Lo2 is scattered light. The external light _Lo2 is non-polarized light.

Of the external light Lo ₂ traveling toward the output surface 22 , light having a polarization direction different from that of the polarizing plate 3 is absorbed by the polarizing plate 3 . The external light Lo ₂ traveling toward the rear surface 23 reaches the reflector 5 from the rear surface 23 . External light Lo ₁ that has not been scattered by the particles 24 reaches the reflector 5 from the rear surface 23 .

The external light Lo ₂ reflected by the reflector 5 enters the diffuser 2 from the rear surface 23 . The external light Lo2 incident on the diffuser ₂ from the rear surface 23 is non-polarized light. External light Lo ₂ emitted from the diffuser 2 enters the polarizing plate 3 . Light in the polarization direction different from the polarization direction of the polarizing plate 3 in the external light Lo ₂ is absorbed by the polarizing plate 3 .

The external light Lo ₁ reflected by the reflector 5 enters the diffuser 2 from the rear surface 23 . The external light Lo ₁ incident on the diffuser 2 from the back surface 23 and scattered by the particles 24 is the external light Lo ₃ . External light Lo ₃ is scattered light. Of the external light Lo ₃ , the external light Lo ₃ in the traveling direction is non-polarized light. External light Lo ₃ emitted from the diffuser 2 enters the polarizing plate 3 . The scattered external light Lo ₃ that has a polarization direction different from that of the polarizing plate 3 is absorbed by the polarizing plate 3 .

The external light Lo ₁ that has entered the diffuser 2 from the back surface 23 and has not been scattered by the particles 24 is polarized light. The outside light Lo ₁ that has not been scattered reaches the polarizing plate 3 from the exit surface 22 . External light Lo ₁ emitted from the diffuser 2 enters the polarizing plate 3 . The non-scattered external light Lo ₁ having a polarization direction different from that of the polarizing plate 3 is absorbed by the polarizing plate 3 .

The amount of outside light Lo that is reflected by the reflector 5 and returns to the room side is less than half the amount of outside light entering the lighting device 100 . Therefore, the visibility of the interior of the illumination device 100 for the observer is reduced. And the depth feeling of the simulated sky can be improved. This effect can be obtained whether the reflection on the reflector 5 is specular reflection or diffuse reflection.

<Modification 1>
FIG. 4 is a configuration diagram showing a schematic configuration of a lighting device 110 according to Modification 1. As shown in FIG. Modification 1 will be described below with reference to FIG.

In the lighting device 110 of Modification 1, the same reference numerals are given to the same components as in the lighting device 100, and the description thereof is omitted.

The illumination device 110 has a polarizing plate 6 . The illumination device 110 differs from the illumination device 100 in this respect.

The polarizing plate 6 is arranged on the rear surface 23 side of the diffuser 2 . The polarizing plate 6 is arranged on the diffuser 2 side with respect to the reflecting plate 5 . A polarizer 6 is arranged between the diffuser 2 and the reflector 5 .

The polarizing plate 6 is a linear polarizing plate. The polarization direction of the polarizer 6 is perpendicular to the polarization direction of the polarizer 3 .

<<Relationship between light _L2 and polarizing plate 6>>
The light _L2 emitted from the rear surface 23 is polarized light. The vibration component due to the polarization of the light _L2 is large on the plane perpendicular to the traveling direction of the light. Therefore, the light L ₂ emitted from the rear surface 23 is absorbed by the polarizing plate 6 . The light L ₂ transmitted through the polarizing plate 6 is reflected by the reflecting plate 5 .

If the light _L2 is specularly reflected by the reflector 5, the polarization direction of the light _L2 is preserved. Therefore, the light L ₂ reflected by the reflector 5 is transmitted through the polarizer 6 . The light L ₂ then enters the diffuser 2 .

The light L2 that is not scattered by the particles 24 as it passes through the diffuser ₂ is polarized light. Therefore, the light L ₂ that is not scattered by the particles 24 is absorbed by the polarizing plate 3 .

The light L2 scattered by the particles 24 as it passes through the diffuser ₂ is unpolarized light. Therefore, the light L ₂ scattered by the particles 24 and having a polarization direction different from that of the polarizing plate 3 is absorbed by the polarizing plate 3 .

When the light _L2 is diffusely reflected by the reflector 5, the polarization direction of the light _L2 is not preserved. That is, the diffusely reflected light _L2 is non-polarized light. Therefore, the light L ₂ reflected by the reflector 5 and having a polarization direction different from that of the polarizer 6 is absorbed by the polarizer 6 . The light L ₂ then enters the diffuser 2 .

The light L2 scattered by the particles 24 as it passes through the diffuser ₂ is polarized light. Therefore, the light L ₂ scattered by the particles 24 and having a polarization direction different from that of the polarizing plate 3 is absorbed by the polarizing plate 3 .

As described above, the visibility of the inside of the illumination device 110 by the observer is reduced. And the depth feeling of the simulated sky can be improved.

<<Relationship between outside light and polarizing plate 3>>
Next, consider a case where external light enters lighting device 110 from the side of the room in which lighting device 110 is installed.

As described above, about half of the external light Lo ₁ is absorbed when passing through the polarizing plate 3 . The external light Lo ₁ transmitted through the polarizing plate 3 is polarized light. The external light Lo ₁ that has not been absorbed enters the diffuser 2 .

The external light Lo ₁ that is not scattered by the particles 24 when passing through the diffuser 2 is polarized light. The external light Lo ₁ transmitted through the diffuser 2 enters the polarizing plate 6 . External light Lo ₁ that is not scattered by the particles 24 is absorbed by the polarizing plate 6 .

Of the external light Lo ₁ scattered by the particles 24 when passing through the diffuser 2 , the external light Lo ₂ scattered in the traveling direction is non-polarized light. The external light Lo ₂ scattered by the particles 24 and having a polarization direction different from that of the polarizing plate 6 is absorbed by the polarizing plate 6 . The external light _Lo2 transmitted through the polarizing plate 6 is polarized light. The external light Lo ₂ transmitted through the polarizing plate 6 reaches the reflecting plate 5 . The external light _Lo2 reaching the reflector 5 is polarized light. The external light Lo ₂ scattered by the particles 24 is reflected by the reflector 5 .

When the external light _Lo2 is specularly reflected by the reflector 5, the polarization direction of the external light _Lo2 is preserved. The external light Lo ₂ specularly reflected by the reflector 5 is transmitted through the polarizer 6 . External light Lo ₂ transmitted through the polarizing plate 6 from the reflector 5 side enters the diffuser 2 .

The external light Lo2 that is not scattered by the particles 24 when passing through the diffuser ₂ is polarized light. The external light Lo ₂ transmitted through the diffuser 2 enters the polarizing plate 3 . External light Lo ₂ that is not scattered by the particles 24 is absorbed by the polarizing plate 3 .

The external light Lo ₃ scattered by the particles 24 when passing through the diffuser 2 is non-polarized light. The external light Lo ₃ scattered by the particles 24 and having a polarization direction different from that of the polarizing plate 3 is absorbed by the polarizing plate 3 .

As described above, the visibility of the inside of the illumination device 110 by the observer is reduced. And the depth feeling of the simulated sky can be improved.

Here, the above effect can be obtained in any case where the reflecting plate 5 has a function of specularly reflecting or diffusely reflecting the incident light.

<Modification 2>
FIG. 5 is a configuration diagram showing a schematic configuration of a lighting device 120 according to Modification 2. As shown in FIG. Modification 2 will be described below with reference to FIG.

In the lighting device 120 of Modified Example 2, the same reference numerals are given to the components common to the lighting device 100 or the lighting device 110, and the description thereof will be omitted.

Illumination device 120 includes wave plate 4 . The wave plate 4 is, for example, a quarter wave plate. A quarter wave plate changes the optical path difference of polarized light oscillating in mutually perpendicular directions by a quarter wavelength. Linearly polarized light that is incident with the plane of polarization tilted by 45 degrees with respect to the optical principal axis of the quarter-wave plate is emitted as circularly polarized light. The wave plate 4 converts incident linearly polarized light into circularly polarized light. The optical principal axis of wave plate 4 is arranged at an angle of 45 degrees with respect to the polarization axis of polarizer 3 . A polarization axis is a polarization direction.

The wave plate 4 is arranged on the rear surface 23 side of the diffuser 2 . The wave plate 4 is arranged on the reflecting surface 51 side with respect to the reflecting plate 5 .

Consider a case where external light Lo ₁ is incident on lighting device 120 from the side of the room in which lighting device 120 is installed.

As described above, about half of the external light Lo ₁ is absorbed when passing through the polarizing plate 3 . The external light Lo ₁ that has not been absorbed enters the diffuser 2 .

The external light Lo ₁ that is not scattered by the particles 24 when passing through the diffuser 2 is polarized light. The external light Lo ₁ transmitted through the diffuser 2 is incident on the wave plate 4 . The external light Lo ₁ that is not scattered by the particles 24 becomes circularly polarized by the wave plate 4 . The external light Lo ₁ circularly polarized by the wavelength plate 4 is reflected by the reflector 5 . The circularly polarized external light Lo ₁ reflected by the reflector 5 is transmitted through the wave plate 4 . The circularly polarized external light Lo ₁ transmitted through the wave plate 4 becomes linearly polarized light.

The polarization direction of the external light Lo ₁ transmitted through the wave plate 4 from the reflector 5 is rotated 90 degrees with respect to the polarization direction of the external light Lo ₁ incident on the wave plate 4 from the diffuser 2 . The external light Lo ₁ whose polarization direction is rotated by 90 degrees is absorbed by the polarizing plate 3 .

The external light Lo2 scattered by the particles 24 when passing through the diffuser ₂ is non-polarized light. The non-polarized external light Lo ₂ is non-polarized light even if it passes through the wave plate 4 . Non-polarized external light Lo ₂ having a polarization direction different from that of the polarizing plate 3 is absorbed by the polarizing plate 3 .

As described above, the visibility of the inside of the illumination device 110 by the observer is reduced. And the depth feeling of the simulated sky can be improved.

Here, if the reflecting plate 5 has a function of specularly reflecting the incident light, the above effects can be obtained. On the other hand, if it has a diffuse reflection function, the effect may be reduced, but that configuration may be used.

In each of the embodiments described above, terms such as "parallel" and "perpendicular" may be used to indicate the positional relationship between parts or the shape of parts. These represent ranges that take into account manufacturing tolerances, assembly variations, and the like. For this reason, when a claim indicates the positional relationship between parts or the shape of a part, it indicates that it includes the range in consideration of manufacturing tolerances, assembly variations, and the like.

Moreover, although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

REFERENCE SIGNS LIST 100, 110, 120 lighting device 1 light source 10 LED element 11 substrate 12 light emitting surface 2 diffuser 21 incident surface 22 exit surface 23 back surface 24 particle 25 base material 3 polarizing plate 4 wavelength Plate 5 Reflector 51 Reflective surface 6 Polarizer L ₁ , L ₂ light Lo, Lo ₁ , Lo ₂ , Lo ₃ outside light T ₀ , T ₁ , T ₂ correlated color temperature.

Claims (11)

A lighting device that emits light that simulates the sky,
a light source that emits light;
a diffuser that includes nanoparticles, guides the incident light, and emits scattered light that is scattered by the nanoparticles and that simulates the sky from an emission surface;
With respect to the diffuser, when the direction side of the emission surface is the front side, and the direction side opposite to the front side is the rear side,
a first polarizing plate disposed on the surface side of the diffuser and transmitting light polarized in a specific direction;
and a reflective plate arranged on the back side of the diffuser and reflecting incident light. In the diffuser, the degree of polarization of the scattered light in the traveling direction of the incident light is relatively low, and the degree of polarization of the scattered light in the direction perpendicular to the traveling direction of the light is relatively high,
The first polarizing plate is a linear polarizing plate,
2. The illumination device according to claim 1, wherein the polarization transmission direction of said first polarizing plate is parallel to a plane perpendicular to a direction in which said light is guided inside said diffuser. 3. The lighting device according to claim 2, wherein the exit surface is formed on one side of the diffuser in a direction perpendicular to the traveling direction of the light. the diffuser is plate-shaped or rod-shaped,
The lighting device according to any one of claims 1 to 3, wherein the exit surface is formed on one surface of the plate shape or formed on a side surface of the bar shape. In the first polarizing plate, outside light incident on the diffuser from the front surface side is scattered by the nanoparticles, directed to the back side, reflected by the reflector, and then emitted from the diffuser. 5. The light absorber according to any one of claims 1 to 4, wherein at least a part of the light and the light emitted from the diffuser after being reflected by the reflector toward the back side without being scattered by the nanoparticles is absorbed. A lighting device as described. 3. The amount of outside light reflected by the reflector and returning to the space side of the outside light incident on the lighting apparatus from the side of the space in which the lighting apparatus is installed is less than half the amount of the incident outside light. 6. The illumination device according to 5. The first polarizing plate absorbs at least part of the light emitted from the light source that is scattered by the nanoparticles, directed to the back side, reflected by the reflector, and emitted from the diffuser. The lighting device according to any one of claims 1 to 6. a second polarizing plate arranged on the back side with respect to the diffuser and arranged on the front side with respect to the reflector;
The second polarizing plate is a linear polarizing plate,
The illumination device according to any one of claims 1 to 7 , wherein the polarization transmission direction of the second polarizing plate is perpendicular to the polarization direction of the first polarizing plate. The lighting device according to any one of claims 1 to 8 , wherein the reflector diffusely reflects incident light. 8. The illumination device according to any one of claims 1 to 7, further comprising a wave plate arranged on the back side with respect to the diffuser and arranged on the front side with respect to the reflector. 11. The lighting device according to claim 10 , wherein the reflecting plate mirror-reflects incident light.

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