Patent Publication Number: US-2023151958-A1

Title: Lighting device, air conditioner, and control system

Description:
TECHNICAL FIELD 
     The present disclosure relates to lighting devices, air conditioners, and control systems using them. 
     BACKGROUND ART 
     There is a lighting technique that improves the spaciousness of a space by emitting light simulating a sky, such as a blue sky, from a main surface to make it look like a window (see, e.g., Patent Literature 1). 
     Also, as an integrated combination of a lighting device and an air conditioner, there is disclosed, in, for example, Patent Literature 2, an example of a circulator including a lighting device. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: International Publication No. 2018/22065 
     Patent Literature 2: Japanese Utility Model Publication No. 59-029633 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, although the lighting technique described in Patent Literature 1 is perceived by an observer as if it were a window, it is still insufficient in providing a more natural view, such as a change in shape of sunlight due to wind from outside or with time. 
     Also, although the circulator with the lighting device described in Patent Literature 2 integrates an air circulation function and a lighting function, it discloses nothing about integrating an air circulation function and a lighting function for the purpose of providing a more natural view and a specific method therefor. 
     Thus, the present disclosure is intended to provide a lighting device, an air conditioner, and a control system that improve the spaciousness of a space in which an observer is present. 
     Solution to Problem 
     An aspect of an air conditioner according to the present disclosure includes: a housing including an inlet and an outlet, and an illumination opening at a position viewable by a user in an installed state; a blower provided in an airflow path connecting the inlet and the outlet; a first light source provided in the housing; a light emitter provided at a position in the housing viewable through the illumination opening, the light emitter including a light incident portion to receive light emitted from the first light source and a first light emission portion to emit first light generated from light emitted from the first light source and including light simulating natural light; and at least one light extractor provided at at least one position around the light emitter in the housing, the at least one light extractor emitting second light that is part of the light received by the light emitter that reaches an edge portion of the light emitter without being emitted as the first light or second light received from the first light source or a second light source different from the first light source without intervention of the light emitter, toward a space that is outside the housing and faces the illumination opening, wherein the at least one light extractor is provided in the airflow path. 
     Also, an aspect of a lighting device according to the present disclosure includes a first light source; a light emitter including a light incident portion to receive light emitted from the first light source and a first light emission portion to emit first light generated from the light and including light simulating natural light; and at least one light extractor provided at at least one position in an edge portion of the light emitter or around the light emitter, the at least one light extractor emitting second light that is part of the light received by the light emitter that reaches an edge portion of the light emitter without being emitted as the first light or second light received from the first light source or a second light source different from the first light source without intervention of the light emitter, toward a space that faces a surface of the light emitter in which the first light emission portion is formed. 
     A control system according to the present disclosure includes: the above air conditioner or lighting device; and a controller to control light emission states of the light emitter and the at least one light extractor of the air conditioner or the lighting device. 
     Advantageous Effects of Invention 
     According to the present disclosure, it is possible to provide a lighting device, an air conditioner, and a control system that improve the spaciousness of a space. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a perspective view illustrating a schematic configuration of a lighting unit. 
         FIG.  2    is a cross-sectional view illustrating a schematic configuration of the lighting unit. 
         FIG.  3    is configuration diagrams illustrating a schematic configuration of a light source provided in the lighting unit. 
         FIG.  4    is a configuration diagram illustrating an arrangement example of light sources provided in the lighting unit. 
         FIG.  5    is a perspective view illustrating an example of a shape of a diffuser provided in the lighting unit. 
         FIG.  6    is a perspective view illustrating another example of the shape of the diffuser provided in the lighting unit. 
         FIG.  7    is an explanatory diagram illustrating an example of guiding of light Li in the diffuser provided in the lighting unit and an example of generation of light Ls. 
         FIG.  8    is an explanatory diagram illustrating an example of a scattered light intensity angular distribution due to Rayleigh scattering by a single particle. 
         FIG.  9    is a cross-sectional view illustrating another configuration example of the lighting unit. 
         FIG.  10    is a cross-sectional view illustrating an example of a configuration of a lighting device according to a first embodiment. 
         FIG.  11    is a cross-sectional view illustrating another example of the lighting device according to the first embodiment. 
         FIG.  12    is explanatory diagrams illustrating another example of a light extractor as viewed from a viewing side and an arrangement example of members. 
         FIG.  13    is a cross-sectional view illustrating a modification of the lighting device according to the first embodiment. 
         FIG.  14    is a perspective view illustrating a modification of the lighting device according to the first embodiment. 
         FIG.  15    is a cross-sectional view illustrating a modification of the lighting device according to the first embodiment. 
         FIG.  16    is a cross-sectional view illustrating a modification of the lighting device according to the first embodiment. 
         FIG.  17    is a cross-sectional view illustrating a modification of the lighting device according to the first embodiment. 
         FIG.  18    is a cross-sectional view illustrating an example of a configuration of an air conditioner according to a second embodiment. 
         FIG.  19    is explanatory diagrams illustrating an example of an airflow path and an optical path in the air conditioner according to the second embodiment. 
         FIG.  20    is cross-sectional views illustrating another example of the air conditioner according to the second embodiment. 
         FIG.  21    is a cross-sectional view illustrating another example of the air conditioner according to the second embodiment. 
         FIG.  22    is cross-sectional views illustrating a modification of the air conditioner according to the second embodiment. 
         FIG.  23    is a cross-sectional view illustrating a modification of the air conditioner according to the second embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
     Hereinafter, embodiments of lighting devices, air conditioners, and control systems according to the present disclosure will be described with reference to the drawings. The following embodiments are merely examples, and it is possible to combine embodiments as appropriate and to modify each embodiment as appropriate. 
     In each drawing described below, elements may be shown on different scales. Also, in each embodiment described below, to facilitate explanation, coordinate axes of an xyz orthogonal coordinate system may be shown in drawings. In this case, a main emission direction that is a direction in which first light is emitted is taken as the +y axis direction. Here, the first light refers to light, such as scattered light simulating the sky, that a lighting device of interest is intended to mainly emit. Moreover, in the case of an edge-lit type light emitter to be described later, a traveling direction of incident light is taken as +z axis direction. 
     Here, the main emission direction can be replaced with a normal direction of a main light emitting surface of the lighting device. The main light emitting surface refers to a particularly designated surface of one or more light emission surfaces of the lighting device or a light emitter provided in the lighting device. More specifically, the main light emitting surface should be a surface that is one of one or more light emission surfaces of the lighting device or a light emitter provided in the lighting device and is particularly intended to be seen by an observer as a light emitting surface from which the first light is emitted. In the case of a lighting device that simulates a window, the main light emitting surface may be, for example, a surface whose normal direction is directed toward a room interior when it is installed as a window. 
     For example, when the light emitter provided in the lighting device has a plate shape, the main light emitting surface may be one of two surfaces connected by side surface(s). Also, hereinafter, in the shape, the two surfaces connected by the side surface(s) may be referred to as main surfaces, and the side surface(s) of the plate shape, i.e., surface(s) forming edge surface(s) of the main surfaces in the plate shape may be referred to simply as edge surface(s) or side surface(s). 
     Also, for example, when the light emitter provided in the lighting device has a rod shape, the main light emitting surface may be one of side surface(s) of the column body or a partial region of the side surface(s) of the column body. Here, the rod shape refers to a shape of a column body having two bases connected by one or more side surfaces. Rod is a general term for column bodies. Hereinafter, in the rod shape, the one or more side surfaces connected by the bases may be referred to as main surface(s), and the bases of the column body, i.e., surfaces forming edge surfaces of the main surface(s) in the rod shape, may be referred to simply as edge surfaces or side surfaces. 
     The main light emitting surface is not limited to a flat surface, and may, for example, include a curved surface or an inclined surface. That is, the main light emitting surface may be curved or inclined, or may have a surface shape obtained by combining two or more of a flat surface, a curved surface, and an inclined surface. Also, when the main light emitting surface includes a curved surface or an inclined surface, the normal direction of the main light emitting surface may be a normal direction of a central portion or a normal direction of a tangent plane. Also, when the main light emitting surface does not have a specific normal direction, such as in the case of a cylindrical shape, a normal direction at an arbitrary position of the main light emitting surface may be taken as the main emission direction. 
     First Embodiment 
     A first embodiment will be described below with reference to the drawings. 
     An example of a lighting unit provided in a lighting device with a blowing function, an air conditioner, and a control system according to the present disclosure will be described first. 
     &lt;Example of Lighting Unit  100 &gt; 
       FIGS.  1  and  2    are schematic configuration diagrams illustrating an example of a lighting unit  100  according to the first embodiment.  FIG.  1    is a perspective view illustrating a schematic configuration of the lighting unit  100 , and  FIG.  2    is a cross-sectional view illustrating the schematic configuration of the lighting unit  100 . 
     The lighting unit  100  includes one or more light sources  10  and a diffuser  20 . In the present disclosure, the diffuser  20  and the one or more light sources  10  paired with the diffuser  20  are referred to collectively as the lighting unit  100 . That is, the lighting unit  100  is a pair of the light source(s)  10  and diffuser  20 . Although the illustration is omitted, the lighting unit  100  may include a frame that supports the light source(s)  10  and diffuser  20 . 
     For convenience of explanation, the following description assumes that the y axis direction is a thickness direction (up-down direction) of the diffuser  20 , the z axis direction is a lateral direction (left-right direction), and the x axis direction is a longitudinal direction (front-rear direction). However, the above directions do not necessarily coincide with directions in an actual installed state. 
     In the example illustrated in  FIG.  2   , the main light emitting surface is a surface f 22 . The main light emitting surface may be a partial region of the surface f 22 . Also, the main light emitting surface may be formed on the surface f 22 . Hereinafter, when the main light emitting surface is formed in a partial region of a surface, the region may be referred to as a main light emitting region, and a region opposite thereto may be referred to as a back side region. 
     Hereinafter, light incident on an edge surface of the diffuser  20  may be referred to as light Li. Also, first light (in this example, scattered light simulating the sky) emitted from the diffuser  20  may be referred to as light Ls. Also, hereinafter, light guided in the diffuser  20  may be referred to as light Lt or transmitted light Lt. Here, “guiding light” refers to transmitting light entering a medium, along a predetermined optical path in the medium. Thus, light Lt does not include light scattered or absorbed in the diffuser  20 . 
     As described later, in the diffuser  20 , the number of emission surfaces through which light Ls is emitted is not limited to one. For example, light Ls can be emitted also through a surface f 23  opposite the surface f 22 . 
     &lt;&lt;Light Source  10 &gt;&gt; 
       FIG.  3    is configuration diagrams illustrating a schematic configuration of a light source provided in the lighting unit  100 . Also,  FIG.  4    is a configuration diagram illustrating an arrangement example of light sources provided in the lighting unit  100 . The light source(s)  10  may be, for example, LED light source(s). Each light source  10  may include a substrate  12  and one or more LED elements  13 , as illustrated in  FIG.  3   . In the example illustrated in  FIG.  3   , multiple LED elements  13  are provided. Also, the LED element(s)  13  are arranged on the substrate  12 . Here, the LED element(s) are an example of light emitting element(s). The light emitting element(s) are not limited to LED element(s), and may be, for example, laser light emitting element(s), fluorescent tube(s), or the like. 
     Each light source  10  is provided to face an edge surface of the diffuser  20  forming an edge portion of the surface f 22  in which the main light emitting surface is formed. For example, each light source  10  includes a light emitting surface f 11  that emits light Li that is incident on the diffuser  20 , and is disposed so that the light emitting surface f 11  faces an edge surface of the diffuser  20  forming an edge portion of the surface f 22  in which the main light emitting surface is formed. 
     As illustrated in  FIG.  4   , the lighting unit  100  may include multiple light sources  10  for one diffuser  20 . Here, it is assumed that a unit of light source(s)  10  is a unit for which on/off control, emitted light amount control, or emitted light color control can be independently performed. The lighting unit  100  may include only one light source  10  for one diffuser  20 . 
     Hereinafter, a group of light sources or light emitting elements (which may be one light source or one light emitting element) that emits, to one diffuser  20 , incident light for generating light Ls may be referred to collectively as the light source(s)  10 . Also, although the function of the light source(s) that emit light Li will be described below with the light source(s)  10  as a subject, the function can be taken as the function of one light source or one light emitting element included in the lighting unit  100 , or taken as the function of a combination of multiple light sources or multiple light emitting elements. 
     As an example, in the configuration example of a light source  10  illustrated in  FIG.  3   , it is possible to consider each LED element  13  in the drawing as one light source  10 . In this case, it is possible that one of the light sources  10  corresponding to the respective LED elements  13  in the drawing has the configuration of the light source  10  illustrated in  FIG.  3    (i.e., a configuration including multiple LED elements  13 ). Also, in the arrangement example of the light sources  10  illustrated in  FIG.  4   , it is possible to consider each light source  10  in the drawing as one LED element  13 . 
     The light source(s)  10  emit light Li that is incident light on the diffuser  20 . The light source(s)  10  emit white light as light Li, for example. Also, the light source(s)  10  may emit, as light Li, light having a predetermined correlated color temperature Tci, for example. 
     The correlated color temperature Tci is, for example, 6500 K. Also, the correlated color temperature Tci is, for example, 5000 K. The correlated color temperatures of lights emitted by the respective light sources  10  may be the same or different. 
     The color of light Li emitted from the light source(s)  10  may be a color other than white. For example, the lighting unit  100  may include, as the light source(s)  10 , a white light source and a green light source. Also, the lighting unit  100  may include, as the light source(s)  10 , a white light source, a green light source, and an orange light source. Also, the lighting unit  100  may include, as the light source(s)  10 , white light sources having different color temperatures. For example, the lighting unit  100  may include, as the light source(s)  10 , a white light source having a high color temperature and a white light source having a low color temperature. 
     Here, the difference in color temperature between the white color having the high color temperature and the white color having the low color temperature is, for example, 8800 K. The correlated color temperature of the white color having the high color temperature is, for example, 14400 K. The correlated color temperature of the white color having the high color temperature is, for example, 11500 K or higher. Also, the correlated color temperature of the white color having the high color temperature is, for example, 19000 K or lower. The correlated color temperature of the white color having the low color temperature is, for example, 5600 K. The correlated color temperature of the white color having the low color temperature is, for example, 5500 K or higher. Also, the correlated color temperature of the white color having the low color temperature is, for example, 6050 K or lower. 
     The light source(s)  10  not only may be disposed to face one edge surface forming the edge portion of the surface f 22  in which the main light emitting surface is formed, as illustrated in  FIG.  4   , but also may be disposed to face two or more edge surfaces forming the edge portion of the surface f 22 , for example. 
     For example, the light source(s)  10  (more specifically, the light emitting surface(s) f 11  thereof) may be disposed to face at least one of one or more edge surfaces of the diffuser  20  forming the edge portion of the surface f 22  in which the main light emitting surface is formed. Also, for example, multiple light sources  10  may be disposed along at least one of the one or more edge surfaces of the diffuser  20  forming the edge portion of the surface f 22  in which the main light emitting surface is formed. Also, as described later, the lighting unit  100  may be configured such that light is received through a back surface (surface f 23 ) of the diffuser  20  and light Ls is emitted through a front surface (surface f 22 ). In this case, the light source(s)  10  may be disposed to face the back surface of the diffuser  20 . Hereinafter, regardless of the position(s) of the light source(s)  10 , any that acts as a light source that causes light Li to be incident on one diffuser  20  is considered as a light source  10  of this embodiment. 
       FIGS.  5  and  6    are perspective views each illustrating an example of a shape of the diffuser  20 . For example, when the diffuser  20  has a rectangular plate shape as illustrated in  FIG.  5   , and includes four side surfaces (surfaces f 21   a , f 21   b , f 21   c , and f 21   d  in the drawing) and two main surfaces (surfaces f 22  and f 23  in the drawing) connected by the four side surfaces, the light source(s)  10  may be disposed as follows. 
     As an example, the light source(s)  10  may be disposed to face the edge surface f 21   a  of the diffuser  20 . In this case, multiple light sources  10  may be disposed along the edge surface f 21   a  of the diffuser  20 . Also, as an example, the light source(s)  10  may be disposed to face the edge surfaces f 21   a  and f 21   b  of the diffuser  20 . In this case, multiple light sources  10  may be disposed along the edge surfaces f 21   a  and f 21   b  of the diffuser  20 . Also, as an example, the light source(s)  10  may be disposed to face the edge surfaces f 21   a , f 21   b , and f 21   c  of the diffuser  20 . In this case, multiple light sources  10  may be disposed along the edge surfaces f 21   a , f 21   b , and f 21   c  of the diffuser  20 . Also, as an example, the light sources  10  may be disposed to face the side surface f 21   a  and the edge surfaces f 21   b , f 21   c , and f 21   d  of the diffuser  20 . In this case, multiple light sources  10  may be disposed along the edge surfaces f 21   a , f 21   b , f 21   c , and f 21   d  of the diffuser  20 . 
     Also, as an example, the light source(s)  10  may be disposed to face at least one of the edge surfaces f 21   a , f 21   b , f 21   c , and f 21   d  of the diffuser  20 . In this case, multiple light sources  10  may be disposed along the at least one of the edge surfaces f 21   a , f 21   b , f 21   c , and f 21   d  of the diffuser  20 . 
     The shape of the diffuser  20  is not limited to a rectangular plate shape. When the shape of the diffuser  20  is another shape, it is possible to apply the above positional relationship between the edge surfaces and the light source(s) to a certain edge surface while replacing it with another edge surface opposite the certain edge surface, another edge surface adjacent to the certain edge surface, or the like, for example. Also, it is possible to apply the above positional relationship between the edge surfaces and the light source(s) to a certain partial region of a continuous side surface while replacing it with another partial region located opposite the certain partial region, another partial region located adjacent to the certain partial region, or the like, for example. 
     Also, for example, when the diffuser  20  has the main light emitting surface formed on a side surface (main surface f 22  in the drawing) of a rod shape connected by two bases (edge surfaces f 21   a  and f 21   b  in the drawing) as illustrated in  FIG.  6   , the light source(s)  10  may be disposed as follows. 
     As an example, the light source(s)  10  may be disposed to face the edge surface f 21   a  of the diffuser  20 . In this case, only one light source  10  or multiple light sources  10  may be disposed for the edge surface f 21   a  of the diffuser  20 . For example, multiple light sources  10  may be disposed along an outer circumference shape of the edge surface f 21   a  or disposed uniformly in the surface. Also, as an example, the light source(s)  10  may be disposed to face the edge surfaces f 21   a  and f 21   b  of the diffuser  20 . In this case, only one light source  10  or multiple light sources  10  may be disposed for each of the edge surfaces f 21   a  and f 21   b  of the diffuser  20 . For example, for each of the edge surfaces f 21   a  and f 21   b , multiple light sources  10  may be disposed along an outer circumference shape of the edge surface or disposed uniformly in the edge surface. 
     Also, for example, in view of zero energy building (ZEB), light obtained by guiding external light (such as sunlight) may be used instead of light Li from the light source(s)  10 . In guiding external light, it is possible to use a daylighting member and/or a light guide for introducing external light and emitting it in a predetermined direction. The lighting unit  100  may include, as a light source  10 , such a daylighting member and/or a light guide. 
     &lt;&lt;Diffuser  20 &gt;&gt; 
     Next, the diffuser  20  will be described with reference to the drawings. In this example, light Li from the light source(s)  10  is incident on an edge portion of the surface f 22  of the diffuser  20  in the +z axis direction, and light Ls generated due to the scattering effect of the diffuser  20  is emitted through the surface f 22 , thereby allowing the diffuser  20  to be seen as a light emitter that emits light close to that from the natural sky. The diffuser  20  is an example of a light emitter provided in the lighting device. Hereinafter, the diffuser  20  serving as a light emitter that emits desired first light may be referred to simply as a light emitter  20  or light emitting panel  20 . The light emitting panel  20  need not necessarily be plate-shaped. 
     The diffuser  20  includes a light incident surface that receives light Li, and a light emission surface (more specifically, the main light emitting surface) that emits light Ls, which is the first light. In this example, the surface f 22 , which is a first surface, corresponds to the light emission surface (in particular, the main light emitting surface), and a surface f 21  that is an edge surface of the surface f 22  in which the main light emitting surface is formed corresponds to the light incident surface. Also, the diffuser  20  may further include, opposite the first surface, the surface f 23 , which is a second surface. 
     The main light emitting surface may be a partial region of the first surface. Also, the main light emitting surface may be formed on the first surface. Also, the light incident surface may be a partial region of the surface f 21  that is an edge surface of the surface f 22 . Also, the light incident surface may be formed on the edge surface. Hereinafter, the first surface may be referred to as the front surface f 22 , and the second surface opposite thereto may be referred to as the back surface  123 . Also, the edge surface may be referred to as the side surface f 21 . 
     The diffuser  20  receives light Li emitted by the light source(s)  10 . Also, the diffuser  20  guides the received light Li. Also, the diffuser  20  guides the received light Li as light Lt. Also, the diffuser  20  emits light Ls while guiding light Lt. 
       FIG.  7    is an explanatory diagram illustrating an example of guiding of light Li in the diffuser provided in the lighting unit and an example of generation of light Ls. As illustrated in  FIG.  7   , the diffuser  20  may receive light Li emitted from the light source(s)  10  through the side surface f 21 , and while guiding it as light Lt inside the diffuser  20 , scatter part of it and emit it as light Ls through at least the front surface f 22 . 
     The diffuser  20  includes a base material  201  and particles  202 . 
     The particles  202  are, for example, nanoparticles. “Nanoparticles” refers to particles having a size on the order of nanometers (nm). In general, “nanoparticles” refers to particles from one to hundreds of nanometers in size. The particles  202  are, for example, particles having a particle diameter on the order of nanometers. 
     The particles  202  may have a spherical shape or another shape. 
     The diffuser  20  may include multiple types of particles  202 . In this case, the particle diameter of the particles  202  may be an average particle diameter. Also, the diffuser  20  may include, as one of the multiple types of particles  202 , particles other than nanoparticles. 
     The particles  202  are, for example, inorganic oxide particles. Examples of the inorganic oxide include ZnO, TiO 2 , ZrO 2 , SiO 2 , and Al 2 O 3 . 
     The particles  202  scatter light Li entering the diffuser  20  to generate light Ls. Also, the particles  202  scatter light Lt transmitted in the diffuser  20  to generate light Ls. 
     The base material  201  contains the particles  202 . The particles  202  may be added in the base material  201 . The particles  202  are, for example, dispersed in the base material  201 . 
     The base material  201  is not particularly limited, but is, for example, a transparent material. The base material  201  need not necessarily be transparent to all the wavelengths of light Li. As an example, the base material  201  may have absorption at a specific wavelength of the wavelengths of light Li. 
     The transmittance (in-line transmittance) of the base material  201  per a light guiding distance of 5 mm is preferably 90% or more, more preferably 95% or more, and still more preferably 98% or more, at one or more design wavelengths. Here, the design wavelength(s) should be predetermined wavelength(s) of the wavelengths of the incident light. The number of the design wavelength(s) is not limited to one, and the design wavelength(s) may be multiple wavelengths or a band of wavelengths (wavelength band). For example, when the incident light is white light, the design wavelength(s) may be one or more of the wavelengths of 450 nm, 550 nm, and 650 nm. The design wavelength(s) may be three wavelengths of 450 nm, 550 nm, and 650 nm. 
     The base material  201  is, for example, solid. The base material  201  may be, for example, a resin plate using thermoplastic polymer, thermosetting resin, photopolymerizable resin, or the like. Also, for the resin plate, it is possible to use acrylic polymer, olefin polymer, vinyl polymer, cellulosic polymer, amide polymer, fluorine polymer, urethane polymer, silicone polymer, imide polymer, or the like. The diffuser  20  may be formed by performing hardening treatment on such material for the base material  201  that has not been hardened, with the particles  202  dispersed therein, for example. The base material  201  is not necessarily solid, and may be liquid, liquid crystalline, or gel-like material. 
     Also, for example, the diffuser  20  may be formed by a porous material made by a sol-gel method, an organic molecule dispersed material, an organic-inorganic hybrid material (also referred to as an organic-inorganic nanocomposite), or a metallic particle dispersed material. As an example, the diffuser  20  may be an organic-inorganic hybrid resin, and may be, for example, a hybrid resin of resin and inorganic oxide. In this case, the diffuser  20  includes, as a substance serving as the particles  202 , inorganic oxide particles formed by sol-gel curing with a base material  201  including an inorganic oxide material and an organic compound as a base. In the present disclosure, minute voids (or holes) or the like formed through such a production process are considered as the particles  202 . 
     Also, the diffuser  20  may be one in which minute irregularities smaller than a wavelength of blue light are formed on a surface of the base material  201 . In this case, the diffuser  20  includes, as the particles  202 , minute recesses or projections formed on the surface of the base material  201 . In this case, the recesses or projections preferably have a maximum diameter on the order of nanometers (e.g., from one to hundreds of nanometers). 
     The specific configuration of the diffuser  20  is not limited as long as the diffuser  20  is a structure having a scattering power. For example, the particles  202  and base material  201  need not necessarily be clearly distinguished as different elements in the diffuser  20 . 
     Also, a translucent functional coating, such as an antireflection coating, an antifouling coating, a heat shielding coating, or a water repellent finish may be applied to at least one surface of the diffuser  20 . Also, in view of the functionality (such as impact resistance, water resistance, or heat resistance) as a window, the diffuser  20  may be sandwiched by two transparent substrates (e.g., glass plates), for example. In this case, the diffuser  20  may be an interlayer of a laminated glass. 
     The diffuser  20  has, for example, a plate shape. The plate shape is not limited to a flat plate shape. Thus, the plate shape may be a curved shape. For example, the diffuser  20  has a shape such that one or both of the front surface f 22  and back surface f 23  (the first surface and second surface) is curved. When the front surface f 22  and back surface f 23  are curved, the directions of the curvatures of both surfaces may be the same or different. For example, both surfaces may be curved surfaces having convex shapes (outwardly convex shapes). Also, for example, both surfaces may be curved surfaces having concave shapes (inwardly convex shapes). Also, for example, it is possible that one of the surfaces is a curved surface having a convex shape and the other of the surfaces is a curved surface having a concave shape. Also, the diffuser  20  may include, on part of its surface, a slope, a step, a recess, a projection, or the like. The above relationship between the front surface f 22  and the back surface f 23  can apply to, for example, the relationship between opposite side surfaces. 
     The diffuser  20  has, for example, a rod shape. The rod shape is not limited to a shape, such as a cylinder, a quadrangular prism, or a triangular prism, that is rectangular in a cross-section parallel to an extending direction of the column body, or a shape such that a perimeter of the column body is constant in a height direction. The extending direction of the column body is, for example, the z axis direction when it is assumed that a base of the column body is the surface f 21   a  in  FIG.  5   . Examples of the rod shape also include shapes equivalent to plate shapes. In this case, a rod shape such that the bases of the column body correspond to the main surfaces of a plate shape and at least one of the bases is the main light emitting surface can be considered as a plate shape. 
     When the diffuser  20  has a rod shape, an extending direction of the column body is set in the z axis direction. The y axis direction, which is an axial direction parallel to the main emission direction, is set in a normal direction of a side surface of the column body. Thus, the main light emitting surface is set to be part of the side surface of the column body. Also, the incident surface is set to be at least one of the bases of the column body. When the diffuser  20  has a rod shape, a region of the side surface of the column body in which the main light emitting surface is formed may be considered as the first surface. Besides, a region of the side surface of the column body opposite the first surface may be considered as the second surface. Also, the two bases of the column body may be considered as a side surface. The side surface may further include a region of the side surface of the column body other than the first surface or second surface. 
     A top view shape (which is a shape on the xz plane in the drawings, and will be referred to below as a front shape) of the diffuser  20  is not particularly limited. For example, the front shape of the diffuser  20  may be a rectangular shape, a polygonal shape, a circular shape, a western barrel shape, or a spool shape, and besides, may be a shape obtained by connecting two or more straight lines, a shape obtained by connecting two or more arcs, a shape obtained by connecting one or more straight lines and one or more arcs, or the like. 
     Also, side view shapes (which are shapes on the xy plane and yz plane in the drawings, and will be referred to below as side shapes) of the diffuser  20  are not particularly limited. For example, each side shape of the diffuser  20  may be a rectangular shape, a western barrel shape, or a spool shape, and besides, may be a shape obtained by connecting four or more straight lines including two opposite straight lines, a shape obtained by connecting two or more straight lines including two opposite straight lines and two or more arcs, or the like. 
     As an example, the diffuser  20  according to the first embodiment is described below as having a plate shape. 
     The side surface f 21  (edge surface) receives light Li emitted by the light source(s)  10 . The side surface f 21  is disposed to face the light emitting surface(s)  11  of the light source(s)  10 , for example. 
     The front surface f 22  (first surface) emits light Ls scattered by the particles  202  (including not only nanoparticles but also compositions (oxides made by sol-gel curing or other compositions), voids (or holes), and recesses or projections on a surface that have sizes on the order of nanometers, which will be referred to below collectively as nano-order optical media). Here, the nano-order optical media are not particularly limited as long as they are optical media (including interfaces) that cause Rayleigh scattering or scattering phenomena like Rayleigh scattering, to light Lt in the base material  201 . Also, the front surface f 22  may emit light Lt guided in the diffuser  20 . For example, the front surface f 22  may emit light reaching an edge portion opposite the incident surface after being guided in the diffuser  20 , as light reproducing sunlight. In the present disclosure, unless otherwise noted, the term “particles  202 ” is used as a general term for the nano-order optical media as described above. 
     Also, the back surface f 23  (second surface) may emit light Ls scattered by the particles  202 . Also, the back surface f 23  may emit light Lt guided in the diffuser  20 . For example, the back surface f 23  may emit light reaching an edge portion opposite the incident surface after being guided in the diffuser  20 , in order to prevent stray light. 
     The back surface f 23  is opposite the front surface f 22 . Light Lt entering the diffuser  20  is reflected and guided by the front surface f 22  and back surface f 23 . The light Lt is guided, for example, by total reflection. For example, the light Lt is guided in the diffuser  20 . 
     Also, a surface other than the front surface f 22  and back surface f 23  may emit light Ls scattered by the particles  202 . Also, a surface other than the front surface f 22  and back surface f 23  may emit light Lt guided in the diffuser  20 . 
     &lt;&lt;Rayleigh Scattering&gt;&gt; 
     Rayleigh scattering, which is a light scattering phenomenon, will be described below with reference to  FIG.  8   .  FIG.  8    is a diagram illustrating an example of a scattered light intensity angular distribution due to Rayleigh scattering by a single particle  202 . 
     Light striking the particle  202  is described to be, for example, light Li emitted from the light source(s). The light striking the particle  202  may be light Lt guided in the diffuser  20 . The vertical axis Z is an axis parallel to a traveling direction of the light Li. The light Li travels in the +Z axis direction. The horizontal axis X is an axis perpendicular to the vertical axis Z. 
     In a case where the particle diameter of a particle is smaller than the wavelengths of visible light, when a light beam strikes the particle, Rayleigh scattering occurs. The wavelengths of visible light range, for example, from 380 nm to 780 nm. Specifically, Rayleigh scattering occurs when a size parameter α given by the particle diameter d of the particle and the wavelength λ of the light satisfies the following formula (1): 
       α&lt;&lt;π. d/λ,   (1)
 
     where “.” denotes multiplication. 
     In Rayleigh scattering, the scattering cross-section a is a parameter that indicates the probability of scattering, and has the relationship of the following formula (2) with the particle diameter d and the wavelength λ of the light: 
       σ∝d6/λ4.  (2)
 
     Formula (2) shows that the scattering cross-section a in Rayleigh scattering is inversely proportional to the fourth power of the wavelength λ of the light. Thus, in Rayleigh scattering, light of a shorter wavelength is more likely to be scattered. Thus, formula (2) shows that blue light is more likely to be scattered than red light. The wavelength λ of the blue light is, for example, 450 nm. The wavelength λ of the red light is, for example, 650 nm. 
       FIG.  8    illustrates an unpolarized scattered light intensity distribution. The particle diameter d of the particle  202  is 100 nm. The refractive index n of the particle  202  is 1.43. The refractive index of the base material  201  is 1.33. The wavelength of the light is 450 nm. 
     As illustrated in  FIG.  8   , in Rayleigh scattering, the scattered light is emitted in all directions. Thus, even when light is caused to enter through the side surface f 21  of the diffuser  20 , it is possible to extract light through the front surface f 22  and back surface f 23  perpendicular to the side surface f 21 . 
     &lt;&lt;Generation of Scattered Light Simulating sky&gt;&gt; 
     The principle of generation of scattered light simulating a sky (in particular a blue sky) will be described below with reference to  FIGS.  7  and  8   . 
     As already described, light Li emitted from the light source(s)  10  enters through the side surface f 21  of the diffuser  20 . The light Li entering through the side surface f 21  is guided as light Lt in the diffuser  20 . The entering light Lt is reflected by the front surface f 22  and back surface f 23  of the diffuser  20  (see  FIG.  7   ). 
     In transmitting in the diffuser  20 , part of the light Lt strikes the particles  202  or the like (or is obstructed by the particles  202  or the like). The light Lt striking the particles  202  or the like is scattered in all directions (see  FIG.  8   ). 
     Of the scattered light, light incident on the front surface f 22  at incident angles not greater than the critical angle is emitted as light Ls through the front surface f 22 . The critical angle refers to the smallest incident angle that yields total reflection when light travels from a part having a higher refractive index to a part having a lower refractive index. 
     Of the scattered light, light incident on the back surface f 23  at incident angles not greater than the critical angle is emitted as light Ls through the back surface f 23 . The critical angle refers to the smallest incident angle that yields total reflection when light travels from a part having a higher refractive index to a part having a lower refractive index. 
     At this time, from formula (2), in Rayleigh scattering, light of a shorter wavelength is more likely to be scattered. Thus, the correlated color temperature Tcs of the scattered light is higher than the correlated color temperature Tci of the incident light. For example, the correlated color temperature Tci is the correlated color temperature of light Li emitted by the light source(s)  10 . For example, the correlated color temperature Tcs is the correlated color temperature of light Ls. 
     When light Li has a spectral distribution over the entire visible light range, blue light is preferentially scattered. Light Li is, for example, white light. The light source(s)  10  include, for example, white LEDs. Thus, by appropriately designing the light source(s)  10  and diffuser  20 , light Ls is made to have a correlated color temperature representing a blue close to the color of the actual sky. 
     Since the amount of light Ls depends on the amount of incident light Li, by appropriately setting the amount of light of the used light source(s)  10 , it is possible to reproduce the sky color while providing sufficient brightness as a lighting device. Also, by appropriately designing the light guiding direction of light Lt, the light guiding distance, and the particle concentration in the diffuser  20 , it is possible to reduce a thickness of the diffuser  20 . For example, with the configuration of this embodiment, the thickness of the diffuser  20  can be set to 100 mm or less. Also, for example, the thickness of the diffuser  20  may be 20 mm or less, and can be 10 mm or less. Moreover, for example, the thickness of the diffuser  20  can be 5 mm or less. Also, for example, when the size(s) (the length(s) in the Y axis direction) of the light source(s)  10  are small, or when light Li is light, such as light emitted from laser light source(s) or concentrated spot light beam(s), whose illuminating area(s) in the incident surface are small, the thickness of the diffuser  20  can be 1 mm or less. 
     In the above example, the description has been made by dividing the surface into two: the front surface f 22  and back surface f 23 . However, when the diffuser  20  has a rod shape and the whole of the main surface(s) (the side surface(s) of the rod shape) is taken as the main light emitting surface, the above front surface f 22  should be replaced with “a region of the main surface(s) that faces in the +y axis direction”, and the above back surface f 23  should be replaced with “a region of the main surface(s) that faces in the −y axis direction” 
       FIG.  9    is a cross-sectional view illustrating another configuration example of the lighting unit  100 . As illustrated in  FIG.  9   , the lighting unit  100  may include a back plate  30  in addition to the light source(s)  10  and diffuser  20 . The back plate  30  is provided on the back surface side (in this example, the −y axis side) of the diffuser  20 . The back plate  30  may be provided to face the back surface f 23  of the diffuser  20 . The distance between the back plate  30  and the diffuser  20  is preferably small. 
     The back plate  30  has a reflecting function or is opaque, and its transmittance is preferably 50% or less, and more preferably 10% or less. 
     The back plate  30  is preferably a diffuse reflector, and more preferably a white diffuse reflector. The back plate  30  may be a light absorber. 
     The back plate  30  may be openable and closable. By the back plate  30  being provided so that it can be opened and closed, when a user wishes to see a space on the back surface side or introduce external light, it is possible to open the back plate  30  to allow the space on the back surface side to be seen through the diffuser  20  or allow external light to be introduced through the diffuser  20 , and the lighting unit  100  can be used also as a window. The back plate  30  may be such that it can be opened and closed by folding the back plate  30  or putting the back plate  30  into a door pocket, like, e.g., a blind or a shutter. 
     It is possible that the shielding state of the back plate  30  can be changed in accordance with a voltage applied to the back plate  30 , like, e.g., a liquid crystal shutter. It is possible that the shielding state of the back plate  30  can be changed in accordance with a voltage applied to the back plate  30 , like, e.g., a liquid crystal panel. 
     Also, the back plate  30  may be supported integrally with the diffuser  20  in a frame  500 . In this case, the back plate  30  may be supported so that it can be opened and closed integrally with the diffuser  20 . 
     &lt;&lt;Advantages of Back Plate  30 &gt;&gt; 
     When the light source(s)  10  are turned on, light Ls is emitted through not only the front surface f 22  but also the back surface f 23  of the diffuser  20 . For example, when it is assumed that the lighting unit  100  is disposed in a wall separating spaces and the front surface f 22  faces one (referred to below as the inside) of the spaces in which an observer is present, light Ls emitted through the back surface f 23  to the other (referred to below as the outside) of the spaces on the back surface f 23  side is not seen by the observer, resulting in loss. Also, when the lighting unit  100  is used also as a window, the emission of light Ls to the outside may cause light pollution for a person other than the observer located in the outside. 
     By providing the back plate  30  on the back surface f 23  side of the diffuser  20 , when the light source(s)  10  are turned on, it is possible to prevent light Ls emitted through the back surface f 23  of the diffuser  20  from being emitted to the outside. Moreover, by using, as the back plate  30 , a member, such as a diffuse reflector, that reflects light Ls emitted through the back surface f 23 , it is possible to cause light Ls emitted through the back surface f 23  to be emitted through the front surface f 22 , thereby improving the light use efficiency of the lighting unit  100 , more specifically the efficiency at which light Li is used as the first light. 
     Thus, providing the back plate  30  on the back surface side of the diffuser  20  improves the light use efficiency of the lighting unit  100  and reduces light leakage to the back surface side. 
     &lt;Configuration of Lighting Device  200 &gt; 
     Next, a lighting device  200  according to the present embodiment will be described with reference to the drawings.  FIG.  10    is a cross-sectional view illustrating an example of a configuration of the lighting device  200  according to the first embodiment. As illustrated in  FIG.  10   , the lighting device  200  includes one or more light sources  10 , a light emitter  20 , and a light extractor  40 . 
     In the lighting device  200 , the light emitter  20  includes a light incident portion  24 , a light guiding portion  25 , a first light emission portion (scattered light emission portion)  26 , and a second light emission portion (transmitted light emission portion)  27 . The light emitter  20  is, for example, the above-described diffuser  20 . 
     The light incident portion  24  receives light emitted from the light source(s)  10 . The light guiding portion  25  guides the received light. Also, the light guiding portion  25  generates first light while guiding the received light. The light guiding portion  25  may include, for example, a medium and a nano-order optical medium, such as light scattering particles, and generate the first light (light Ls) by scattering the received light with the nano-order optical medium while guiding the received light in the medium. 
     The first light emission portion  26  emits the first light generated by the light guiding portion  25 . The first light emission portion  26  corresponds to the above-described main light emitting surface. Also, the second light emission portion  27  emits part of the received light that reaches a light guiding edge portion without becoming the first light, i.e., transmitted light reaching the light guiding edge portion. Hereinafter, light emitted from the second light emission portion  27  may be referred to as light Lo. 
     The light emitter  20  includes the light incident portion  24  at a first edge portion, and the second light emission portion  27  at a second edge portion opposite the first edge portion, for example. In cases such as when the light emitter  20  is of a back-lit type and receives light through the back surface, the second light emission portion  27  may be provided in the same surface as the first light emission portion  26 . Also, as described later, in cases such as when a light deflector  50  or the like that changes a traveling direction of the transmitted light is provided at a position opposite the light incident portion  24 , the position at which the second light emission portion  27  is provided is not limited to the second edge portion. For example, regardless of whether it is an edge-lit type or a back-lit type, the second light emission portion  27  may be provided in a partial region of a surface in which the first light emission portion  26  is provided. 
     Light Li emitted from the light source(s)  10  enters the light emitter  20  through the light incident portion  24 . Light Li entering the light emitter  20  turns into light Ls and exits through the first light emission portion  26  while being guided as light Lt in the light guiding portion  25  in the light emitter  20 . Also, light Li entering the light emitter  20  is emitted as light Lo through the second light emission portion  27  after being guided as light Lt in the light guiding portion  25  in the light emitter  20 . 
     For example, when the light emitter  20  is the above-described diffuser  20 , which generates the first light by using Rayleigh scattering or a scattering phenomenon like Rayleigh scattering, the correlated color temperature of light Lo emitted through the second light emission portion  27  is lower than the correlated color temperature of light Ls emitted through the first light emission portion  26 . 
     In the lighting device  200  of the present embodiment, at least part of the light Lo emitted through the second light emission portion  27  is emitted in the same direction as light Ls (in the illustrated example, in the +y axis direction, which is a direction toward a space facing the main light emitting surface in which the first light emission portion  26  is provided) by the light extractor  40  provided near the second light emission portion  27 . 
     The light extractor  40  may have a deflecting function, specifically a function of changing the traveling direction of light Lo emitted through the second light emission portion  27  and directing it in a particular direction. The particular direction may be a direction (which is not limited to the +y axis direction and may be the −y axis direction) perpendicular to the light guiding direction of light Lt, may be the traveling direction of light Ls, may be a direction toward the space facing the main light emitting surface in which the first light emission portion  26  is provided, as already described, and may be a direction toward a space in which a user of the lighting device is present. The deflection mentioned here includes deflection, such as refraction, in transmission, and deflection due to reflection. 
     Also, in the light extractor  40 , for example, a lens, a mirror, a film, a surface coating, or the like may be formed to control refraction, reflection, diffusion, transmission, or the like of light Lo, which is emitted light. Thus, the light extractor  40  should have a function of affecting the incident light to change the traveling direction, spread, illuminating area, or intensity distribution of the light and direct it in the particular direction. 
     As a specific example, light Lo emitted through the second light emission portion  27  is scattered light spreading in an angular direction, and in order to deflect the scattered light and convert it into light for illuminating a space (a space in which an observer is present) located in the particular direction, the light extractor  40  may be a mirror having a curvature. With such a configuration, light reflected by the light extractor  40  can be controlled to be substantially parallel light and travel in the particular direction. 
     Also, to provide a configuration that does not dazzle a person who is located in the particular direction and looks at the light extractor  40 , it is possible to provide the light extractor  40  with a diffusing function. In this case, it is possible to convert light emitted from the second light emission portion  27  into light traveling in the particular direction while reducing dazzling of a person. 
     Although the illustration is omitted, another light extractor  40  may be provided at the first edge portion at which the light source(s)  10  are provided. However, in this case, the light extractor  40  deflects light emitted from the first edge portion, the light source(s)  10 , or another light source and converts it into light traveling in the particular direction, in a space facing the first edge portion of the light emitter  20  at which the light incident portion  24  is provided, instead of deflecting light emitted through the second light emission portion  27  of the light emitter  20  and converting it into light traveling in the particular direction. Hereinafter, such a light extractor  40  provided in a space facing the first edge portion may be referred to as a second light extractor  40   a.    
     By providing such a light extractor  40 , it is possible, for example, to make light Lo simulate sunlight. Specifically, it is possible to make an observer feel as if the sun were present on the back surface side of the light emitter  20  and sunlight from the sun were coming through the light emitter  20  or its periphery. Also, for example, when the light emitter  20  simulates a window by emitting the first light simulating the sky, by providing the light extractor  40  at a position viewable by an observer, it is possible to make the light extractor  40  look as if it were a window frame illuminated by sunlight from the sun. In this case, it is possible to make the reflectance of a partial region of the light extractor  40  small, thereby making the region a non-light emitting region. By providing such a non-light emitting region in a surface of the light extractor  40 , it is possible to represent a sunny area and a shaded area on the light extractor  40 . 
       FIG.  11 A  is a cross-sectional view illustrating another configuration example of the lighting device  200 . A lighting device  200   a  illustrated in  FIG.  11 A  includes a light limiter  80  in addition to the configuration of the lighting device  210  illustrated in  FIG.  10   . The light limiter  80  is disposed between the light emitter  20  (in particular the second light emission portion  27 ) and the light extractor  40 , and has a function of reducing the light emitted from the light emitter  20  toward the light extractor  40 . By providing such a light limiter  80  for blocking part of light Lo on an optical path from the second light emission portion  27  to the light extractor  40 , a partial region of the light extractor  40  can be made a non-light emitting region. 
     The light limiter  80  is formed by, for example, a member, such as a mask, that absorbs or reflects at least part of the incident light. In the example illustrated in  FIG.  11   , a substantially triangular member that limits transmittance of light is provided as the light limiter  80 . In this example, more specifically, the light limiter  80  absorbs at least part of the light emitted through the second light emission portion  27  and reaching the light limiter  80 . 
     The light limiter  80  thus attenuates the intensity of the light traveling from the second light emission portion  27  toward the light extractor  40  in the partial region, so that a shadow of the light limiter  80  is projected to the light extractor  40 . The intensity of light is also referred to as the amount of light per unit area or luminance. 
       FIG.  11 B  illustrates a situation in which a shadow of the light limiter  80  is projected to the light extractor  40 . The light extractor  40  in this example includes a bright region  401  and a dark region  402 . The dark region  402  is, for example, a region to which the shadow of the light limiter  80  is projected. In this example, the intensity of light emitted from the dark region  402  is lower than the intensity of light emitted from the bright region  401 . 
     Also,  FIG.  11 C  is a top view illustrating an arrangement example of members for forming the bright region  401  and dark region  402  illustrated in  FIG.  11 B .  FIG.  11 C  corresponds to an A-A cross-sectional view of  FIG.  11 B . As illustrated in  FIG.  11 C , for example, the light limiter  80  may be disposed in the dark region  402  or a region corresponding to the dark region  402  on an optical path before light Lo emitted through the second light emission portion  27  is incident on an incident surface of the light extractor  40  and emitted as light traveling in the particular direction from an emission surface of the light extractor  40 . 
     The light limiter  80  may be disposed, for example, between an edge portion of the light emitter  20  at which the second light emission portion  27  is provided and the light extractor  40 , on a surface of the light extractor  40  in which an incident surface or an emission surface of light Lo emitted through the second light emission portion  27  is formed, or in various interface(s) located in the light extractor  40 , in such a manner as to cover the dark region  402  or a region corresponding to the dark region  402 . 
       FIG.  12    is explanatory diagrams illustrating another example of the light extractor  40  as viewed from a viewing side and an arrangement example of members.  FIG.  12 A  illustrates a situation in which a shadow of the light limiter  80  is projected to the light extractor  40 .  FIG.  12 B  is a top view illustrating an arrangement example of members for forming a bright region  401  and a dark region  402  illustrated in  FIG.  12 A .  FIG.  12 B  corresponds to a B-B cross-sectional view of  FIG.  12 A . As illustrated in  FIG.  12 B , for example, it is possible that the light limiter  80  is disposed in a region corresponding to the entire region of an incident surface of the light extractor  40 , and an optical member (a thin film serving as an antireflection layer for a base material of the light limiter  80 ) that functions to increase the intensity of the transmitted light, an opening, or the like is provided in the bright region  401  or a region corresponding to the bright region  401  on an optical path before light Lo emitted through the second light emission portion  27  is incident on the incident surface of the light extractor  40  and emitted as light traveling in the particular direction from the emission surface of the light extractor  40 , in the light limiter  80 . The example illustrated in  FIG.  12 B  is an example in which an opening  81  is provided in a region corresponding to the bright region  401  in the light limiter  80 . 
     By providing such a light limiter  80 , it is possible to make an observer feel as if a sunny area and a shaded area were formed on the light extractor  40  by light coming from the sun through the light emitter  20 , providing a more natural view. 
     The light extractor  40  may be provided as a modification of the light deflector  50  to be described later, or may be provided separately from the light deflector  50 . In this case, the light extractor  40  may be provided together with the light deflector  50  in one lighting device. 
     &lt;First Modification&gt; 
       FIG.  13    is a cross-sectional view illustrating another example of the lighting device according to the first embodiment. A lighting device  210  illustrated in  FIG.  13    is an example in which the light emitter  20  includes the light deflector  50  corresponding to the above-described light extractor  40 . The light deflector  50  is provided at an edge portion of the light emitter  20 . The light deflector  50  is provided, for example, at an edge portion opposite the edge portion at which the light incident portion  24  is provided. In the illustrated example, the light deflector  50  is provided at one of the side surfaces of the light emitter  20 . 
     The light deflector  50  changes the traveling direction of light Lt. The light deflector  50  may change the traveling direction of light Lt to the above-described particular direction. Also, the light deflector  50  may include a reflecting surface f 51 . In this case, the light deflector  50  may reflect light Lt reaching the light deflector  50 , at the reflecting surface f 51 , thereby changing the traveling direction of light Lt. 
     The reflecting surface  51  is, for example, a mirror surface. The reflecting surface f 51  is, for example, a diffuse reflecting surface. The reflecting surface f 51  is provided by, for example, metal deposition or white paint. 
     The light deflector  50  may be formed by, for example, cutting off part of the surface of the light emitter  20 . In this case, the cut surface is the reflecting surface f 51 . An edge portion of the light emitter  20  including the cut surface is taken as the light deflector  50 . As such, the light emitter  20  may include the light deflector  50 . 
     The light deflector  50  may be integrated with or separate from the light guiding portion  25 . For example, when the light deflector  50  is provided integrally with the light guiding portion  25 , the light deflector  50  may be formed in an edge portion of the light guiding portion  25 . In this case, particles  202  may be included in the edge portion. Also, for example, when the light deflector  50  is provided separately from the light guiding portion  25 , a member forming the light deflector  50  and a member forming the light guiding portion  25  may be bonded together. In this case, the member forming the light deflector  50  and the member forming the light guiding portion  25  are optically connected to each other. 
     Also, in the example illustrated in  FIG.  13   , the first light emission portion  26  and second light emission portion  27  are both provided in the light emission surface (front surface) taken as the main light emitting surface. As illustrated in  FIG.  13   , the first light emission portion  26  and second light emission portion  27  are preferably provided in different regions in the light emission surface. However, this does not apply to cases such as when particles  202  are included in the edge portion in which the light deflector  50  is formed. Thus, the region in which the first light emission portion  26  is provided and the region in which the second light emission portion  27  is provided may partially overlap. For example, it is possible that the first light emission portion  26  is provided over the entire region of the front surface of the light emitter  20  and the second light emission portion  27  is provided in a partial region of the front surface of the light emitter  20 . 
     Even in the configuration in which the light emitter  20  includes the light deflector  50  in this manner, it is possible to provide the same effects as the configuration including the light extractor  40 . Also in this example, the light deflector  50  may have a light scattering function. The light scattering function may be provided by applying surface treatment such as emboss processing to the reflecting surface f 51 . Also, the light scattering function may be provided by, for example, attaching a reflective and diffusive film to the reflecting surface f 51 , or applying white paint to the reflecting surface f 51 . 
     A light scattering function may be provided to a member in which the light deflector  50  is formed or the second light emission portion  27 . In this case, it may be provided by dispersing light scattering particles in the member in which the light deflector  50  is formed, by applying surface treatment such as emboss processing or a light diffusing coating to the second light emission portion  27 , or by attaching a light diffusing film to the second light emission portion  27 . 
     &lt;Second Modification&gt; 
       FIGS.  14  and  15    are explanatory diagrams illustrating another example of the lighting device according to the first embodiment.  FIG.  14    is a perspective view of a lighting device  220  that is another example of the lighting device according to the first embodiment, and  FIG.  15    is a cross-sectional view of the lighting device  220 . 
     The lighting device  220  includes one or more light sources  10 , a light emitter  20 , a frame member  60 , and one or more frame light sources  70 . 
     The frame member  60  is provided at at least one position in a space around the light emitter  20 . The frame member  60  is provided, for example, in a predetermined region including a certain position in the space around the light emitter  20 . Here, the space around the light emitter  20  includes space(s) facing side surface(s) of the light emitter and space(s) facing main surface(s) of the light emitter. The frame member  60  may be provided, for example, in a predetermined region of a space in front of the light emitter  20  (a space facing the front surface that is the main light emitting surface). Also, the frame member  60  may be provided, for example, in a predetermined region of a space lateral to the light emitter  20  (a space facing a side surface). Also, the frame member  60  may be provided, for example, in a predetermined region of a space behind the light emitter (a space facing the back surface opposite the main light emitting surface). The example illustrated in  FIGS.  14  and  15    is an example in which the frame member  60  is provided in front of the light emitter  20 . In the example illustrated in  FIGS.  14  and  15   , a gap is provided between the light emitter  20  and the frame member  60 , but the frame member  60  may be provided in contact with the light emitter  20 . 
     The frame member  60  may be disposed to surround the light emitter  20  or a space facing the main light emitting surface of the light emitter  20 . Also, the frame member  60  may be disposed to surround both the light emitter  20  and a space facing the main light emitting surface of the light emitter  20 . For example, the frame member  60  may be disposed in a space around the light emitter  20  to surround a space (a viewing side space) facing the main light emitting surface of the light emitter  20 . Here, the space around the light emitter  20  may be, for example, a space within 500 mm. For example, the frame member  60  may be provided at a position within 500 mm in at least one of the front, rear, and lateral directions of the light emitter  20 . 
     As already described, the frame member  60  may be disposed in contact with the light emitter  20 , i.e., with no space between the frame member  60  and the light emitter  20 . In this case, the light emitter  20  and frame member  60  may be connected to each other with a buffer or the like therebetween, for example. 
     Also, it is possible that the frame member  60  is divided into multiple parts and the parts are arranged with spaces therebetween. In this case, the arrangement direction is not particularly limited, and may be a longitudinal direction of each side of the main light emitting region, may be the traveling direction of the first light, or may be a direction outward from a center like a double shade structure. Also, the frame member  60  may be arranged in two or more directions. As such, various designs can be provided to the shape of the frame member  60 . 
     The frame member  60  includes an incident surface f 61  and an emission surface f 62 . In the example illustrated in  FIG.  14   , the incident surface f 61  is a surface on an anti-viewing side of the frame member  60 , and the emission surface f 62  is a surface on a viewing side of the frame member  60 . Here, the viewing side refers to a side that is seen by an observer located on the main light emitting surface side of the light emitter  20  in a state in which the lighting device is installed, and the anti-viewing side refers to the opposite side. The example illustrated in  FIG.  14    is an example of a transmission-type frame member. When the frame member  60  is a reflection-type frame member, the incident surface f 61  and emission surface f 62  are formed in the same surface. More specifically, the incident surface f 61  and emission surface f 62  are both formed in a surface on the viewing side of the frame member  60 . 
     For example, for convenience, the frame member  60  may be divided into multiple areas (in the example illustrated in  FIG.  14   , frame members  60   a ,  60   b ,  60   c , and  60   d  corresponding to the respective sides of a rectangular main light emitting region  501 , or the like). The division of the frame member  60  is not limited to the example illustrated in  FIG.  14   . 
     The frame light source(s)  70  are provided behind the frame member  60  (i.e., on the anti-viewing side as viewed from an observer). That is, the lighting device  220  includes the frame light source(s)  70  on the incident surface f 61  side of the frame member  60 . 
     The frame light source(s)  70  are, for example, LED light source(s). Also, the frame light source(s)  70  may be, for example, laser light emitting element(s), fluorescent tube(s), or the like. Although the illustration is omitted, each frame light source  70  may include a substrate and light emitting element(s), as with each light source  10 . Also, each frame light source  70  may include multiple light emitting elements, as with each light source  10 . Also, the number of the frame light source(s)  70  may be two or more, as with the light source(s)  10 . 
     For example, when the frame member  60  is divided into multiple areas, the lighting device  220  may be configured such that at least one frame light source  70  is provided for each area of the frame member  60 . As an example, when the main light emitting region  501  is polygonal and the frame member  60  is provided to surround the main light emitting region  501 , multiple frame light sources  70  may be provided along each side of the main light emitting region  501 . Also, as another example, when the main light emitting region  501  is polygonal and the frame member  60  is provided to correspond to opposite sides of the main light emitting region  501 , multiple frame light sources  70  may be provided along each of the opposite sides of the main light emitting region  501 . 
     The frame light source(s)  70  emit, for example, white light. Also, the color of light emitted by the frame light source(s)  70  may be a color other than white. The frame light source(s)  70  may include, for example, a white LED light source and an orange LED light source. Also, the frame light source(s)  70  may include, for example, a white LED light source having a low color temperature and a white LED light source having a high color temperature. 
     The frame member  60  is formed by, for example, a light diffuser. The light diffuser may be one obtained by dispersing fine particles in a transparent member, or may be, for example, one obtained by applying surface treatment such as emboss processing to a surface of a transparent member, one obtained by applying a light diffusing film to a surface of a transparent member, or one obtained by applying white paint to a surface of a transparent member. 
     Also, the frame member  60  may be formed by, for example, a transparent member and a light diffuser. In this case, the light diffuser may be provided on the anti-viewing side of the transparent member, the viewing side of the transparent member, or both the sides. The light diffuser may be formed by, for example, coating the transparent member with a thin film containing fine particles. The frame member  60  may be formed by applying or placing such a light diffusing thin film to or on the transparent member. 
     Also, in the case of a reflection type, the frame member  60  may be formed by, for example, a reflector and a light diffuser. In this case, the light diffuser is provided on the viewing side of the reflector. 
     Light emitted from the frame light source(s)  70  enters the frame member  60  through the incident surface f 61  of the frame member  60  and exits through the emission surface f 62 . At this time, when the frame member  60  has a light diffusing function, the light entering the frame member  60  is converted into diffused light and emitted through the emission surface f 62 . In this manner, an observer is made to see the frame member  60  as a second light emitter that simulates sunlight. The frame member  60  may have, for example, a function of affecting the incident light to change the traveling direction, spread, illuminating area, or intensity distribution of the light and direct it in a particular direction (in this example, toward a space in which a user is present, i.e., a viewing side space). 
     In the frame member  60 , the entire emission surface f 62  may emit light, or only a partial region may emit light. Also, for example, when the frame member  60  is divided into multiple areas, it is possible to determine, for each area, whether to place the area in a light emitting state or a non-light emitting state. By controlling the lighting states of the frame light sources  70  for each area or for each of positions of the incident surface f 61  facing them, it is possible to place a subset of the areas or a partial region in a light emitting state or a non-light emitting state. 
     For example, by providing a light limiter  80  as described above between the frame light source(s)  70  and the frame member  60 , the intensity of light emitted from a partial region of the emission surface f 62  of the frame member  60  can be made lower than the intensity of light emitted from another region. Thus, by providing the light limiter  80 , it is possible to represent a sunny area and a shaded area on the emission surface f 62  of the frame member  60 . The frame member  60  may include the light limiter  80 . In this case, the light limiter  80  is provided, for example, on an optical path before light emitted from the frame light source(s)  70  is emitted through the emission surface f 62  of the frame member  60 . 
     Also, although  FIG.  15    illustrates an example in which the light source(s)  10  and frame light source(s)  70  are separately provided, the light source(s)  10  may provide the function of the frame light source(s)  70 . In this case, it is possible to provide, between the light source(s)  10  and the light emitter  20 , a light splitter (whose illustration is omitted) that splits light into light traveling to the light incident surface of the light emitter  20  and light traveling to the incident surface f 61  of the frame member  60 . In this case, a reflecting function portion of the light splitter may be provided with a light diffusing function so that the light traveling to the incident surface f 61  of the frame member  60  is diffused light. Alternatively, it is also possible that side emitting type light source(s) are used as the light source(s)  10 , a region other than a region of the light source(s)  10  facing the light incident surface of the light emitter  20  is covered with a reflector or the like, and while light emitted from the region facing the light incident surface of the light emitter  20  is allowed to travel toward the light incident surface of the light emitter  20 , light emitted from the region other than the region is directed toward the incident surface f 61  of the frame member  60 . 
     Also, the above-described light extractors  40  (including the second light extractor  40   a ) are each an example of the reflection type frame member  60 . 
     Also, as illustrated in  FIGS.  16  and  17   , a light extractor  40  or light deflector  50  as described above may be provided instead of the frame light source(s)  70 . A lighting device  220   a  illustrated in  FIG.  16    is an example in which a light extractor  40  is provided instead of the frame light source(s)  70 . The light extractor  40  illustrated in this example is provided in a frame  500 . In the lighting device  220   a  illustrated in  FIG.  16   , light that is emitted from the light source(s)  10 , enters through the light incident portion  24  of the light emitter  20 , is guided in the light emitter  20 , is guided in the light emitter  20 , is guided in the light emitter  20 , is emitted through the second light emission portion  27 , and is deflected by the light extractor  40  is incident on the incident surface f 61  of the frame member  60 . 
     Also, a lighting device  220   b  illustrated in  FIG.  17    is an example in which a light deflector  50  is provided instead of the frame light source(s)  70 . The light deflector  50  illustrated in this example is formed by a reflecting surface f 51  provided in a frame  500 . In the lighting device  220   b  illustrated in  FIG.  17   , light that is emitted from the light source(s)  10 , enters through the light incident portion  24  of the light emitter  20 , is guided in the light emitter  20 , is emitted through the second light emission portion  27 , and is deflected by the light deflector  50  is incident on the incident surface f 61  of the frame member  60 . 
     By providing the frame member  60  in this manner, the frame member  60  can simulate a sunny region and a shaded region in a window frame, or light emitted from the frame member  60  can simulate sunlight reflected in a sunny region of a window frame. Thus, even in an environment into which no sunlight is actually coming from the sun, it is possible to provide an observer with a natural view that looks as if sunlight from the sun were coming through the light emitter  20 . 
     Also, in the above configurations, each of the lighting devices  200 ,  200   a ,  200   b ,  210 ,  220 ,  220   a ,  220   b  may include a drive mechanism that changes a position, an angle, or a shape, or a combination thereof of at least one of the light extractor(s)  40 , frame member  60 , and light limiter  80 . By changing the position, angle, or shape of at least one of the light extractor(s)  40 , frame member  60 , and light limiter  80  with the drive mechanism, it is possible to change a direction of light simulating sunlight from the sun or change a position, a size, or a shape of a sunny region or a shaded region formed on the light extractor(s)  40  or frame member  60 , thereby making an observer perceive a more natural view. 
     For example, by changing the position, angle, or shape of the light limiter  80  with the drive mechanism, it is possible to change, with time, the projection pattern of the shadow formed on the light extractor  40 , light deflector  50 , or frame member  60  located ahead of the light limiter  80 . In the case of changing the projection pattern of the shadow, the configuration may be configured to reproduce, for example, the change in solar altitude with the time of day and the season, so that an angle of a substantially triangular shape of the shadow is changed. Also, for example, by changing the position(s), angle(s), or shape(s) of the light extractor(s)  40  or frame member  60  with the drive mechanism, it is possible to change, with time, an emission direction or an illuminating area of the light simulating sunlight. Also, by changing a positional relationship with the light limiter  80 , it is possible to change, with time, the projection pattern of the shadow formed on the light extractor  40  or frame member  60 . Also, for shape change, it is possible, for example, to use a drive mechanism such as a motor to unfold an intended member in a folded state or fold the intended member in an unfolded state. 
     In the above lighting devices, the light emitter  20  is not limited to the diffuser  20  as described above that emits scattered light produced by Rayleigh scattering, and is also not limited to one that emits scattered light simulating the sky. That is, the first light emitted by the light emitter  20  is not limited to scattered light produced by Rayleigh scattering, and is also not limited to scattered light simulating the sky. For example, the first light may be light simulating light such as light reflected on the surface of water or sunlight filtered through leaves. In the present disclosure, the first light is not particularly limited as long as it includes light simulating light (also referred to below as natural light) produced from sunlight in nature. The first light may be, for example, light including natural light and artificially produced light. By arranging a light emitter that emits such first light and a frame member to be described later in a predetermined positional relationship, it is possible to provide a space including a natural view, thus improving the spaciousness of a space. 
     Thus, although the specific configuration of the light emitter  20  is not limited, examples of the light emitter  20  include a light guiding panel that is a light transmissive member that diffuses light by transmitting, reflecting, and guiding the light, a liquid crystal panel using a liquid crystal and a backlight, and an organic electroluminescence (EL) panel. Also, preferred examples of the light emitter  20  include a diffuser as described above that reproduces the color (i.e., a transparent blue color or the like) of a natural sky, such as a blue sky, by using a diffusing material as described above that exhibits, to incident light, Rayleigh scattering or a scattering power similar thereto. However, as already described, the light emitter  20  is not limited to any of the above examples as long as it can emit desired first light through the main light emitting surface. 
     Also, the frame member  60  is not limited to any of the above examples. For example, it is possible to use, as the frame member  60 , a frame forming part described in PCT application PCT/JP2019/020917 by the present applicant. 
     Hereinafter, the light extractors  40 , light deflector  50 , and frame member  60  that emit light simulating sunlight in a particular direction may be referred to simply as light extractors or sunlight extractors without particularly distinguishing them from each other. 
     Second Embodiment 
     Next, an air conditioner according to a second embodiment will be described with reference to the drawings. The air conditioner of the present embodiment includes, in addition to a configuration of a so-called air conditioner (typical air conditioner), elements of a lighting device as described above, thereby providing an air conditioner with a lighting function. 
       FIG.  18    is a cross-sectional view illustrating an example of a configuration of the air conditioner according to the second embodiment. An air conditioner  300  illustrated in  FIG.  18    is one obtained by incorporating a light emitter  20  and one or more light sources  10  as described above into a ceiling-embedded type air conditioner. As illustrated in  FIG.  18   , the air conditioner  300  includes, in a housing  301  including an inlet  306 , an outlet  307 , and an illumination opening  308 , a heat exchanger  302 , a blower  303 , one or more flaps  304  provided in an airflow path connecting the inlet  306  and outlet  307 , a filter  305 , the light emitter  20 , and the light source(s)  10 . In the air conditioner  300  of this embodiment, the flap(s)  304  are rotatably held by the housing  301  and form part of the airflow path. 
     The inlet  306  is provided, for example, in a lower portion of the housing  301 , i.e., a lower surface that is seen as a ceiling panel by an observer after the installation. The inlet  306  need not necessarily be located in the lower portion of the housing  301 , and may be provided, for example, in a side plate of the housing  301  (see the example of  FIG.  20   ). In this case, a second inlet that sucks indoor air into a space behind the ceiling may be provided in a ceiling surface away from the air conditioner  300 . 
     The filter  305  and heat exchanger  302  are disposed beyond the inlet  306 . For example, when a main body of the air conditioner has a substantially rectangular shape and the inlet  306  is formed along four side surfaces forming the rectangular shape, the heat exchanger  302  may be disposed in a substantially rectangular shape to correspond to the four side surfaces. 
     The filter  305  and heat exchanger  302  are not limited to the example in the drawing as long as they are disposed before the blower  303  in a flow path (referred to below simply as an airflow path) of air sucked in through the inlet  306 . 
     When the air conditioner  300  is operated, the blower  303  starts, and indoor air in a room flows into the housing  301  through the inlet  306 . The air flowing into the housing  301  passes through an airflow path formed by flaps  304   a  and  304   b  and enters the heat exchanger  302  through the filter  305 . Upon entering the heat exchanger  302 , the air is subjected to heat exchange by the heat exchanger  302 , then taken into the blower  303 , and blown into the room through the outlet  307 . Then, after air-conditioning the room, the air is sucked into the housing  301  through the inlet  306  again, and circulates. 
     Also, in this example, the illumination opening  308  is provided in a lower portion of the housing  301 , i.e., a lower surface panel that faces toward the room after the installation, and the light emitter  20  is disposed so that the main light emitting surface is located at a position of the illumination opening  308 . The illumination opening  308  may be provided, for example, in a central portion of the lower surface panel of the air conditioner. The above light emitter  20  is provided to cover the illumination opening  308 . More specifically, in the air conditioner  300 , the light emitter  20  is located in a region surrounded by the outlet  307  in a lower portion of the air conditioner  300  so that the main light emitting surface or main light emitting region is viewable. The light source(s)  10  are provided at position(s) facing the light incident surface of the light emitter  20 . In the example illustrated in  FIG.  18   , the light source(s)  10  are provided at position(s) facing at least one side surface of the light emitter  20 . 
     Moreover, in the air conditioner  300  of this example, one of the flap(s)  304  forming part of the airflow path connecting the inlet  306  and outlet  307  is provided with the function of the light extractor  40  as described above. In this example, it can be said that a light extractor  40  is disposed on the airflow path of the ceiling-embedded type air conditioner  300 . A typical air conditioner includes, in addition to a heat exchanger and a blower, near an inlet  306  and an outlet  307  on an airflow path, a flap that controls the flow (wind direction) of air flowing in or out, and a drive mechanism that drives it. The air conditioner  300  of this example includes, in addition to the configuration of such a typical air conditioner, the light emitter  20  and light source(s)  10 . 
     In the example illustrated in  FIG.  18   , two flaps are provided in an outward direction along the shape of the ceiling panel of the air conditioner  300  in such a manner as to define the inlet  306  and outlet  307  in the airflow path. In this example, at least one of the flaps is used as a light extractor  40  (sunlight extractor). More specifically, a flap  304   c  located closest to a side surface opposite a side surface of the light emitter  20  at which the light source(s)  10  are provided is used as a light extractor  40 . 
     In this example, light emitted through the second light emission portion  27  of the light emitter  20  is emitted in a particular direction (in this example, into a room space that is a space facing the main light emitting surface of the light emitter  20 ) by the flap  304   c , which functions also as a light extractor  40 . Moreover, in this example, it is possible to change an angle of the flap  304   c  by means of a flap drive mechanism (not illustrated) provided in the air conditioner  300 . Thereby, it is possible to control an emission direction of light Lo together with the wind direction. 
       FIG.  19    illustrates an example of the airflow path and an optical path of the air conditioner  300 .  FIG.  19 A  illustrates an example of an airflow in the air conditioner  300 , and  FIG.  19 B  illustrates an example of light emitted from the air conditioner  300 . 
     In the example illustrated in  FIG.  18   , of the openings serving as the ends of the airflow path, one opening closer to the center is illustrated as the outlet  307 , and the other opening farther from the center is illustrated as the inlet  306 . However, as illustrated in  FIG.  19 A , which of the two regions defined by the two flaps is used as the outlet side or inlet side is not particularly limited. For example, it is possible that the opening closer to the center is used as the inlet  306 , and the opening farther from the center is used as the outlet  307 . Also, it is possible to determine which is used as the outlet side or inlet side, depending on a blowing direction of the blower  303 . 
     Also, as illustrated in  FIG.  19 B , in this example, light Li emitted from the light source(s)  10 , which are provided in the housing  301 , enters the light emitter  20 , which is also provided in the housing  301 . When light Li enters the light emitter  20 , the light emitter  20  guides it as light Lt. While guiding light Lt, the light emitter  20  emits light Ls generated from light Lt, through the main light emitting surface (in the example of the drawing, the lower surface). Also, the light emitter  20  emits, as light Lo, light Lt reaching the opposite end portion without becoming light Ls. Light Lo emitted from the light emitter  20  is deflected by the flap  304   c  used as a light extractor  40  to become light traveling toward the room. 
     Also,  FIG.  20    is cross-sectional views illustrating another configuration example of the inlet  306  and outlet  307  of the air conditioner  300 . In an air conditioner  300   a  illustrated in  FIG.  20   , the inlet  306  is provided in a side plate of the housing  301 . In the example illustrated in  FIG.  20   , two flaps  304  arranged in an outward direction are provided in an airflow path connected to the outlet  307 . However, only one flap may be provided for one side. Thus, in the air conditioner with a lighting function of the present embodiment, the position of the inlet  306  and the number of the flap(s)  304  are not particularly limited. 
     Also,  FIG.  21    is a cross-sectional view illustrating another example of the air conditioner according to the present embodiment. An air conditioner  300   b  illustrated in  FIG.  21    is an example in which a light emitter  20  and one or more light sources  10  are incorporated in an indoor unit of a wall-installed type air conditioner. Also in this example, the basic configuration as an air conditioner is not particularly limited, and known ones can be used. For example, although the illustration is omitted, the air conditioner  300   b  may include an outdoor unit in addition to the indoor unit  31 . 
     In the air conditioner  300   b  illustrated in  FIG.  21   , an inlet  306  is provided, for example, in an upper portion of the indoor unit  31 , i.e., an upper surface that faces a ceiling after the installation. Also, an illumination opening  308  may be provided, for example, in a front portion of the indoor unit  31 , i.e., a front surface that faces toward a room in an installed state. The illumination opening  308  should be provided at a position viewable by a user in an installed state, and may be provided at a position other than the front surface. Also, an outlet  307  may be provided, for example, in a lower portion of a housing  301 , more specifically, a lower surface or a lower end of the front surface of the indoor unit  31 . It may be basically the same as the ceiling-embedded type air conditioners  300  and  300   a  except that an installation direction of the light emitter  20  is different. In the example illustrated in  FIG.  21   , only one flap  304  is provided in the lower portion of the indoor unit  31 . However, two or more flaps  304  may be provided. In this case, multiple flaps  304  may be provided along the shape of a front panel of the indoor unit  31  in such a manner as to surround the light emitter  20 . In this case, for one side, two or more flaps  304  may be provided in an outward direction. 
     The air conditioner  300  includes the light emitter  20  and flap(s)  304  as described above. Thereby, more natural light and wind can be felt. Also, by using, as the light emitter  20 , an edge-lit type light emitter such as the above diffuser  20 , it is possible to easily embed it in a panel on a viewing side without increasing the size of the air conditioner and without interfering with the original air conditioning function. 
     &lt;First Modification&gt; 
       FIG.  22    is explanatory diagrams illustrating a first modification of the air conditioner  300 .  FIG.  22 A  is a cross-sectional view illustrating a configuration example of an air conditioner  310  as the first modification of the air conditioner  300 , and  FIG.  22 B  is a view of the air conditioner  310  as viewed from a viewing side. The air conditioner  310  illustrated in  FIG.  22    further includes one or more frame light sources  70  that emit light toward one or more flaps  304  provided near edge portion(s) of the light emitter  20  at which the second light emission portion  27  is not provided. 
     Light emitting surface(s) of the frame light source(s)  70  face the flap(s)  304 . Thereby, the flap(s)  304  provided around the edge portion(s) of the light emitter  20  at which the second light emission portion  27  is not provided are used as second light extractor(s)  40   a . For example, when the main light emitting region  501  is polygonal and flaps  304  are provided to surround the main light emitting region  501 , the frame light source(s)  70  may be provided along all the sides (excluding a side corresponding to an edge portion at which the second light emission portion  27  is provided) of the main light emitting region  501 . For example, in the example of the drawing, frame light source(s)  70  that emit light toward flaps  304   a ,  304   e , and  304   g  may be provided. Thereby, the flaps  304   a ,  304   e , and  304   g  can be used as second light extractors  40   a  (sunlight extractors). 
     In the example illustrated in  FIG.  22   , the main light emitting region  501  is polygonal and the flaps  304  are provided to surround the main light emitting region  501 . However, for example, in cases such as when the main light emitting region  501  is rectangular and flap(s)  304  are provided only along a subset, such as two opposite sides, of the sides of the main light emitting region  501 , the frame light source(s)  70  need not necessarily be provided along all the sides of the main light emitting region  501 . Thus, the frame light source(s)  70  should be provided to flap(s)  304  on which no light from the second light emission portion  27  of the light emitter  20  is incident, out of the flap(s)  304  located near the main light emitting region  501 . This does not apply to flaps  304  that are not used for sunlight representation. 
     In the air conditioner  310  illustrated in  FIG.  22   , light emitted by the frame light source(s)  70  is deflected by the flaps  304  used as second light extractors  40   a  to become light traveling toward the room. Thus, since sunlight extractors can be provided to two or more sides of the light emitter  20 , it is possible to make an observer feel more natural light and wind. As an example, it is possible to make flaps  304  surrounding the light emitter  20  look as if they were window frames illuminated by sunlight from the sun. Also, since the amount of light traveling toward the room can be increased, sufficient brightness as a lighting device can be held. 
     Also, it is possible to provide each flap  304  serving as a light extractor  40  or second light extractor  40   a  with a light diffusing function similar to those of the light extractor  40  and second light extractor  40   a.    
     Although the illustration is omitted, also in the air conditioner, as with the light extractor  40  and second light extractor  40   a  in the lighting device, one or more light limiters  80  may be provided on optical paths before light reaches the respective flaps  304  serving as a light extractor  40  or second light extractor  40   a  (more specifically, between the light emitter  20  and the flap  304   c  serving as a light extractor  40 , or between the frame light source(s)  70  and the flap  304   a ,  304   e , or  304   g  serving as a second light extractor  40   a ). 
     Here, the light limiter(s)  80  may be fixed on the above optical paths, or may be rotatably or displaceably held on the above optical paths. In the latter case, the air conditioner may further include a drive mechanism for the light limiter(s)  80 . For example, by changing position(s), shape(s), or angle(s) of the light limiter(s)  80  with the drive mechanism, it is possible to change, with time, the projection pattern(s) of the shadow(s). 
     Alternatively, the light limiter(s)  80  may be swung by using air flowing through the airflow path. For example, multiple mirrors held by plate springs may be disposed as the light limiter(s)  80 . The plate springs or mirrors swing by receiving wind from the blower  303 , thereby changing the projection patterns onto the light extractor  40  (in this example, the flap  304   c ) and the second light extractor(s)  40   a  (in this example, the flap  304   a ). 
     By swinging not only the flaps  304  used as a light extractor  40  and second light extractor(s)  40   a  but also the light limiter(s)  80 , it is possible to make an observer feel as if sunlight filtered through leaves were coming in. Also, the projection patterns are changed by wind, so that the wind can be visually perceived. 
     &lt;Second Modification&gt; 
       FIG.  23    is a cross-sectional view illustrating a further modification of the air conditioner according to the present embodiment. In an air conditioner  320  illustrated in  FIG.  23   , the light source(s)  10 , the frame light source(s)  70 , and an edge surface of the light emitter  20  are disposed so that they are not visible from the room. More specifically, in the air conditioner  320 , the openings of the housing  301 , the light source(s)  10 , the frame light source(s)  70 , and the edge surface(s) (in particular, the second light emission portion  27 ) of the light emitter  20  are disposed so that the light source(s)  10 , the frame light source(s)  70 , and the second light emission portion  27  of the light emitter  20  are not located on a straight line in a line-of-sight direction in the case of looking into the housing  301  through an opening of the airflow path that is defined by the housing  301  and is closest to the light emitter  20 . The line-of-sight direction at this time may be, for example, a direction (α 1  in the drawing) that is maximally directed at a center in the case of looking into the housing  301  through the above opening of the airflow path. The line-of-sight direction α 1  may be a straight line connecting an edge portion β 2  of the housing  301  that defines a lower end of an inner peripheral surface on the outer periphery side of the opening of the airflow path closest to the light emitter  20  and an edge portion β 1  of the housing  301  that defines an upper end of an inner peripheral surface on the inner periphery side of the opening. 
     In this manner, the light source(s)  10 , frame light source(s)  70 , and the edge surface(s) of the light emitter  20  are arranged in view of the line-of-sight direction. Thereby, more natural light and wind can be felt. 
     Although the present embodiment describes an example in which a lighting function is incorporated into an air conditioner including a heat exchanger, the air conditioner into which a lighting function is incorporated may be a so-called blower that only blows air without performing heat exchange. Even such a blower is referred to as an air conditioner in the present disclosure. 
     Also, although the illustration is omitted, the lighting device and the air conditioner with a lighting function according to the present disclosure may include a controller that controls the light emission states (on/off and/or emitted light color) of the light emitter  20  and the sunlight extractor(s) provided therearound. 
     The controller may include, for example, a first light source driver that turns on, dims, or turns off the light source(s)  10  and a second light source driver that turns on, dims, or turns off the frame light source(s) (or auxiliary light source(s)). The first light source driver and second light source driver may perform the controls in cooperation with each other, or may perform the controls independently of each other. 
     An example of the control of the emitted light colors of the light emitter  20  and sunlight extractor(s) by the controller will be described below. When it is assumed that the light emitter  20  is a lighting panel that simulates a blue sky in fair weather seen through a window, it is preferable that the bright region(s)  401  can simulate sunny region(s) of a window frame in fair weather and the dark region(s)  402  can simulate shaded region(s) of the window frame in fair weather. In such a case, it is easy to imagine that while the bright region(s)  401 , i.e., simulated sunny region(s), in a turned-on state are brighter than the light emitter  20  in a turned-on state, the light (second light) simulating sunlight emitted from the bright region(s)  401  has a lower color temperature than the light (first light) simulating a blue sky emitted from the main light emitting surface of the light emitter  20 . For example, the luminance of a blue sky in fair weather is about 5000 cd/m2, and the luminance of a sunny region on a white diffuse reflecting surface commonly used in window frame members is about 30000 cd/m2. Also, the color temperature of light from a blue sky in fair weather is about 20000 K, and the color temperature of light from a sunny region on a white diffuse reflecting surface is about 5000 K. Thus, it is preferable that the magnitude relationships in luminance and emitted light color temperature between the main light emitting surface or main light emitting region of the light emitter  20  and the bright region(s)  401  of the sunlight extractor(s) be maintained as described above. However, when the sky seen through a window includes not only a blue sky in fair weather but also a sky in rainy weather or a sky in cloudy weather or both of them, it is more preferable that the ratio in luminance (or emitted luminous flux) between the main light emitting surface or main light emitting region of the light emitter  20  and the bright region(s)  401  of the sunlight extractor(s) be in the range of 20:1 to 1:30. 
     For example, the luminance of the main light emitting surface or main light emitting region of the light emitter  20  in a turned-on state may be 100 to 6000 cd/m2, and more preferably 500 to 3000 cd/m2. On the other hand, the luminance of the bright region(s)  401  of the sunlight extractor(s) in a turned-on state may be 300 to 30000 cd/m2, and more preferably 1000 to 12000 cd/m2. Also, the correlated color temperature of the first light emitted from the light emitter  20  may be 10000 to 100000 K, and more preferably 20000 to 80000 K. On the other hand, the correlated color temperature of the second light emitted from the bright region(s)  401  may be 2000 to 7000 K, and more preferably 2500 to 6500 K. 
     Also, the difference in correlated color temperature between the first light emitted by the light emitter  20  and the second light emitted by the bright region(s)  401  of the sunlight extractor(s) may be not less than 20000 K and not more than 98000 K. 
     Moreover, when the sunlight extractor(s) include the dark region(s)  402 , the ratio in luminance (or luminous flux) between the bright region(s)  401  and the dark region(s)  402  in a turned-on state is preferably in the range of 100:1 to 20:1, and more preferably about 10:1. However, this relationship is a condition met in fair weather, and does not apply to conditions such as cloudy weather or night. 
     The controller may be provided at a location different from that of a main body of the lighting device or air conditioner. For example, an external server may include the controller. In this case, the main body of the lighting device or air conditioner and the server including the controller are connected to each other through a network. For example, it is possible that, in a control system that controls multiple air conditioners in a building or the like, a lighting function is incorporated in each air conditioner, and a controller provided in the control system performs control of the air conditioning functions and control of the lighting functions. Also, it is possible that, in a control system that controls multiple lighting devices, a pair of a light emitter  20  and light extractor(s) as described above is provided in each lighting device, and a controller provided in the control system performs control of the light emission states of the light emitters  20  and control of the light emission states of the light extractors. 
     REFERENCE SIGNS LIST 
       100  lighting unit 
       10  light source 
       12  substrate 
       13  LED element (light emitting element) 
       20  diffuser (light emitter) 
       24  light incident portion 
       25  light guiding portion 
       26  first light emission portion 
       27  second light emission portion 
       201  base material 
       202  particle 
       30  back plate 
       40  light extractor 
       50  light deflector 
       60  frame member 
       70  frame light source 
       501  main light emitting region 
       200 ,  200   a ,  210 ,  220 ,  220   a ,  220   b  lighting device 
       300 ,  300   a ,  300   b ,  310 ,  320  air conditioner 
       31  indoor unit 
       301  housing 
       302  heat exchanger 
       303  blower 
       304   a  to  304   h  flap 
       305  filter 
       306  inlet 
       307  outlet 
       308  illumination opening 
       500  frame