JP7333578B2 - Planar lighting device - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act Published in the publication "HABITATION STRUCTURAL LIGHTING 2018-2019 Vol.174" issued by Oderic Co., Ltd. on May 18, 2018 Oderic Co., Ltd. published on October 1, 2018 Published in the published publication “At Home Lighting Catalog Vol. Published on its own website on June 11, June 20, 2018 and August 9, 2018

The present invention relates to a planar illumination device.

A lighting device using light-emitting diodes is known. Such lighting devices generally have higher luminous efficiency and lower power consumption than conventional incandescent lamps and the like.

A lighting device using light emitting diodes includes, for example, a light guide plate, a plurality of light emitting elements arranged along the outer periphery of the light guide plate, and a reflective sheet provided on the reflection side surface of the light guide plate. There is a device (Reference 1). With such a structure, a thin planar lighting device can be realized.

JP 2014-135290 A

It is conceivable that such a planar illumination device is controlled by, for example, an infrared remote controller. However, if, for example, an infrared receiver is provided above the reflective sheet, the infrared ray will be reflected by the reflective sheet, making it impossible for the receiver to receive the infrared ray. For example, if a through-hole is provided in the reflective sheet, infrared rays can be received by the receiver above the reflective sheet, but such a through-hole appears as a dark area when illuminated.

In order to solve such a problem, the cited document 1 embeds a receiver of an infrared remote control in a part of a support frame that supports the light guide plate. However, in such a configuration, the shape of the support frame is restricted, and it may not be possible to realize a free design.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a planar illumination device that can be suitably operated without impairing design.

A planar illumination device according to an embodiment of the present invention includes a light guide plate having an upper surface and a lower surface, the lower surface being arranged to serve as a light emitting surface, and a plurality of light emitting elements arranged along the outer circumference of the light guide plate. a reflective layer provided along the upper surface of the light guide plate; a radio wave receiver provided at a position farther from the light emitting surface of the light guide plate than the reflective layer; and a control unit for controlling the voltage supplied to the element.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the planar illuminating device which can be operated suitably, without spoiling design.

1 is a perspective view showing the appearance of a planar illumination device 100 according to a first embodiment of the invention; FIG. 2 is an exploded perspective view of the planar illumination device 100. FIG. FIG. 2 is a perspective view of a body frame 101 of the planar lighting device 100; FIG. 2 is a schematic cross-sectional view of the planar illumination device 100; 5 is an enlarged view of the portion indicated by A in FIG. 4; FIG. 2 is a circuit diagram showing a schematic configuration of a light emitting circuit of the planar illumination device 100; FIG. FIG. 5 is a diagram showing the configuration of a planar lighting device 500 according to a first comparative example; FIG. 10 is a diagram showing the configuration of a planar illumination device 600 according to a second comparative example; FIG. 11 is a perspective view of a planar lighting device 700 according to a second embodiment of the present invention as viewed from below; FIG. 7 is a perspective view of the planar lighting device 700 as viewed from above; 7 is an exploded perspective view of the same planar illumination device 700. FIG.

Next, a schematic configuration of a planar illumination device 100 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG.

FIG. 1 is a perspective view of a planar lighting device 100 attached to a ceiling 300 as viewed from below. As shown in the figure, the illumination device 100 according to the present embodiment has a substantially disk-like overall shape in which a circular diffuser panel 102 is arranged inside an annular body frame 101 when attached to a ceiling 300 . are doing. In use, illumination is provided through diffuser panel 102 .

FIG. 2 is an exploded perspective view of the planar illumination device 100. FIG. As shown in FIG. 2, the planar lighting device 100 according to this embodiment includes a holding member 107 attached to an adapter 301 provided on a ceiling 300, a body frame 101 attached to the holding member 107, and a holding member 107 and a body frame 101, a diffusion panel 102, a light guide plate 103, a high reflection sheet 104, a sponge 105, and a chassis .

The body frame 101 is configured in a substantially annular shape in this embodiment. The body frame 101 accommodates the diffusion panel 102 , the light guide plate 103 , the high reflection sheet 104 , the sponge 105 , the chassis 106 and the holding member 107 . A holding portion 108 for holding the diffusion panel 102 and the like is provided at the lower end of the body frame 101 . The holding portion 108 according to the present embodiment is an extending portion that extends inward from the lower end portion of the body frame 101 .

Further, a plurality of light emitting elements 201 are provided on the inner peripheral surface of the body frame 101 as shown in FIG. The light emitting element 201 is, for example, a light emitting diode. The plurality of light emitting elements 201 are mounted on a flexible printed circuit board 202 provided along the inner peripheral surface of the body frame 101 and arranged in a line along the inner peripheral surface of the body frame 101 . As shown in FIG. 5 , the plurality of light emitting elements 201 are arranged along the outer periphery of the light guide plate 103 and irradiate the side surface of the light guide plate 103 with light.

The diffusion panel 102 is made of a material with high transmittance and diffuses the light emitted from the light guide plate 103 .

The light guide plate 103 is, for example, a transparent disk made of a material having high transmittance such as acrylic resin. A side surface (peripheral surface) of the light guide plate 103 is configured to function as a light incident end surface on which light emitted from the light emitting element 201 enters and travels through the light guide plate 103 . The lower surface of the light guide plate 103 is a surface (light emitting surface) on the side that emits planar light by light incident from the side surface, and the upper surface (surface opposite to the light emitting surface) of the light guide plate 103 emits light incident from the side surface. This is the surface (reflecting surface) on the side that reflects light toward the lower surface (light emitting surface). The light emitting surface and the reflecting surface of the light guide plate 103 may be subjected to light diffusion treatment such as a dot pattern or groove pattern provided by printing or processing, for example.

The high reflection sheet 104 has a high reflectance, and reflects the light emitted from the light emitting element 201 and reaching the reflecting surface of the light guide plate 103 by internal reflection in the light guide plate 103 toward the light emitting surface. The highly reflective sheet 104 according to this embodiment covers the entire reflecting surface of the light guide plate 103 .

A sponge 105 is provided between the high reflection sheet 104 and the chassis 106, and contributes to mitigation of manufacturing errors and assembly errors.

The chassis 106 is made of a highly rigid material such as metal and, as shown in FIG. 2, has a substantially annular shape with an opening 106a in the center. As shown in FIGS. 4 and 5 , the chassis 106 sandwiches the diffusion panel 102 , the light guide plate 103 , the high reflection sheet 104 and the sponge 105 together with the holding portion 108 of the body frame 101 . Chassis 106 also holds control unit 400 and wiring and the like for connecting control unit 400 to other components. That is, the space partitioned by the upper surface of the chassis 106 (the surface opposite to the light guide plate 103 ) and the inner peripheral surface of the body frame 101 accommodates the control unit 400 , wiring, and the like. Note that the control unit 400 includes, for example, a substrate 401 and a plurality of elements 402 mounted on the substrate 401 . The element 402 is, for example, a microcomputer, an integrated circuit, a transistor, a resistor, a capacitor, or the like. Further, the element 402 includes a radio wave transmitting/receiving section 403 for transmitting/receiving radio waves.

The radio wave transmission/reception unit 403 may use, for example, 2.4 GHz band Bluetooth (registered trademark), Wi-Fi (registered trademark), or ZigBee (registered trademark). Further, the radio wave transmitting/receiving section 403 may use radio waves in a so-called Sub-GHz frequency band such as 315 MHz band, 400 MHz band, 868 MHz band, 915 MHz band, 920 MHz band, and 950 MHz band.

Further, the radio wave transmitting/receiving unit 403 includes an antenna 403a used for transmitting/receiving radio waves. As shown in FIG. 2, the antenna 403a is provided at a position corresponding to the opening 106a provided in the center of the chassis 106, and is provided at a certain distance from the chassis 106. As shown in FIG. However, when the chassis 106 is made of a material other than metal, and radio waves are not shielded by the chassis 106, the chassis 106 and the antenna 403a may be provided close to each other.

The holding member 107 is attached to the adapter 301 provided on the ceiling 300 and holds the body frame 101, the diffusion panel 102, the light guide plate 103, the high reflection sheet 104, the sponge 105, and the chassis .

In the illustrated example, the body frame 101 and the chassis 106 are configured in a substantially annular shape, and the diffusion panel 102, the light guide plate 103, the high reflection sheet 104, the sponge 105, and the holding member 107 are provided. It is configured in a substantially circular shape. That is, these configurations have a shape along a circle. However, these configurations may have a shape along an ellipse, a shape along a polygon such as a quadrangle, or other shapes.

Next, a light emitting circuit including the light emitting element 201 according to this embodiment will be described with reference to FIG. FIG. 6 is a circuit diagram showing a schematic configuration of a light emitting circuit.

As shown, the light emitting circuit according to this embodiment includes a plurality of light emitting elements 201 connected in series between a first terminal 203 and a second terminal 204 . The first terminal 203, the second terminal 204, and various wirings are provided on, for example, a flexible printed circuit board 202 (FIG. 3).

The control section 400 includes a voltage supply section 406 and a signal control section 407 .

The voltage supply unit 406 includes, for example, a rectifier circuit 411 that rectifies the AC voltage output from the adapter 301 and a PWM control circuit 412 that generates a PWM signal based on the output voltage of the rectifier circuit 411 . Rectifier circuit 411 includes, for example, a bridge circuit including a plurality of diodes, and a smoothing capacitor connected between output terminals of this bridge circuit. The PWM control circuit 412 receives, for example, a dimming signal and a toning signal from the signal control unit 407 and generates a PWM signal, which is connected to the third terminal 404 connected to the first terminal 203 and the second terminal 204. supplied between the fourth terminals 405 .

The signal control unit 407 includes, for example, the radio transmission/reception unit 403 described above and a signal processing circuit 422 such as a microcomputer or an integrated circuit that controls the voltage supply unit 406 according to the output signal of the radio transmission/reception unit 403 .

The signal control unit 407 may be configured, for example, so that the planar lighting device according to this embodiment can build a network together with other devices. For example, the signal control unit 407 includes a storage device such as a register that stores group IDs and device IDs. In this configuration, when the signal control unit 407 receives a command to establish a network from another device, the signal control unit 407 determines whether the group ID included in this command matches the group ID of its own device. do. If they match, communication is established with the other device, and if they do not match, communication is not established. When communication is established, the signal control unit 407 transmits a command to construct the network. If another device having the same group ID as the self device exists within a predetermined distance range from the self device, communication is established between these devices. The construction of such a so-called mesh network may be set so as to be automatically performed at the time of initial operation.

It should be noted that the "other devices" referred to here include, for example, planar lighting devices other than the own device, other lighting devices, terminal devices such as remote controls, smartphones, tablet terminals, etc., and relays for relaying communication. Devices and sensors such as illuminance sensors and human sensors are included. The terminal device outputs, for example, various commands to the lighting device (for example, commands for instructing ON/OFF switching of the lighting device, dimming, toning, switching between normal lighting mode and night-light lighting mode, etc.). Also, the terminal device may be capable of receiving various types of information from lighting devices, sensors, and the like, and may be capable of executing arithmetic processing and the like based on such information. For example, the terminal device monitors the operating status of these lighting devices, etc., through two-way communication with the lighting devices, etc., within the network, and displays the operating status, power consumption, electricity charges, etc. calculated from the operating status on the display. may be configured to be able to be displayed on the

Each device in the network may have a radio wave transmitting/receiving unit capable of transmitting/receiving radio waves, and may perform communication using radio waves, like the planar illumination device according to the present embodiment. Unlike infrared rays, radio waves do not have directivity. Therefore, when a command is output from one device in the network, the command is received by another device with the strongest reception strength of the radio wave emitted from this device. be. At this time, the device that transmits commands and the like functions as a master, and the device that receives commands and the like functions as a slave.

A device that receives a command or the like determines whether or not the device ID included in the command or the like matches its own device ID. If they match, a signal is sent to the signal processing circuit 422 according to the received command or the like, and the command or the like is sent to other devices in the network arranged adjacently. On the other hand, if they do not match, the command or the like is transmitted to other devices in the network arranged adjacently without transmitting the signal to the signal processing circuit 422 . At this time, the device that outputs commands and the like functions as a master. In this way, each device functions as a slave during reception and as a master during transmission, so that commands and the like are transmitted to all devices within the mesh network, and all devices within the mesh network are integrated. can be controlled by

Next, in order to explain the effects of the planar lighting device according to the present embodiment, planar lighting devices 200 according to first and second comparative examples will be described.

FIG. 7 is a diagram for explaining a planar lighting device 500 according to a first comparative example. FIG. 7A is a schematic cross-sectional view of the planar illumination device 500. FIG. FIG. 7(b) is an enlarged view of the portion indicated by B in FIG. 7(a). FIG. 7C is a schematic bottom view showing the light emitting surface of the planar lighting device 500. FIG. In addition, in the following description, the same code|symbol is attached|subjected to the structure similar to this embodiment, and description is abbreviate|omitted.

The planar lighting device 500 is basically configured in the same manner as the planar lighting device 100, but includes a control unit 501 having an infrared receiving unit 502 instead of the control unit 400 including the radio wave transmitting/receiving unit 403. there is Further, the high reflection sheet 504, the sponge 505 and the holding member 506 are provided with through-holes 503 for exposing the infrared receiving section 502. As shown in FIG.

In such a configuration, an infrared signal transmitted from the remote controller is made to reach the infrared receiver 502 through the diffuser panel 102, the light guide plate 103, the high reflection sheet 504, the sponge 505, and the through holes 503 of the holding member 506. However, there is a difference in the amount of light between the area where the through-holes 503 are not present and the area where the through-holes 503 are present on the light-emitting surface of the diffusion panel 102 . As a result, the area of the light emitting surface of the diffusion panel 102 where the through holes 503 are present becomes a dark area.

FIG. 8 is a diagram for explaining a planar illumination device 600 according to a second comparative example. FIG. 8A is a schematic cross-sectional view of the planar lighting device 600. FIG. FIG. 8(b) is an enlarged view of the portion indicated by C in FIG. 8(a). FIG. 8C is a schematic bottom view showing the light emitting surface of the planar lighting device 600. FIG. In addition, in the following description, the same code|symbol is attached|subjected to the structure similar to this embodiment, and description is abbreviate|omitted.

The planar illumination device 600 is basically configured in the same manner as the planar illumination device 100, but a projection 601a is provided on a part of the body frame 601, and an infrared receiving section 602 is attached to the projection 601a. is provided. Further, the planar illumination device 600 is provided with a control unit 603 that does not include the radio wave transmitting/receiving unit 403 instead of the control unit 400 that includes the radio wave transmitting/receiving unit 403 . The controller 603 is connected to the infrared receiver 602 .

In such a configuration, it is necessary to provide a projection 601a on a portion of the body frame 601. As shown in FIG. Therefore, the shape of the body frame is greatly restricted, and it may not be possible to realize a free design.

In order to solve the problems in these first and second comparative examples, as a result of extensive studies, the present inventors found that the high reflective sheet 104 reflects visible light and infrared light, but the so-called radio wave (for example, It was found that electromagnetic waves in a frequency band of about 300 MHz to 3.00 GHz) can pass through. That is, if the radio wave transmitting/receiving section 403 is employed instead of the infrared receiving section as in the planar lighting device 100 according to the present embodiment, the planar lighting device 500 (FIG. 7) according to the first comparative example can be obtained. There is no need to provide a through hole in the high reflection sheet 104, and there is no need to provide a projection on the body frame unlike the planar illumination device 600 (FIG. 8) according to the second comparative example. Therefore, it is possible to provide a planar lighting device that can be suitably operated without spoiling the design.

Further, the planar illumination device 100 including the light guide plate 103 and the plurality of light emitting elements 201 arranged in a line along the outer periphery of the light guide plate 103 can be easily made thinner as in the present embodiment. By providing a radio wave receiving section for receiving radio waves in such a lighting device 100, it becomes possible to make the frame of the thin planar lighting device 100 into a shape without projections, thereby realizing brightness suitable for the main lighting of a living room. While doing so, you can create a stylish living room space by suppressing the presence like a recessed lighting (downlight). In particular, according to the planar lighting device 100 according to the present embodiment, it is possible to realize a frame shape without projections, so that the accumulation of dust and the like is suppressed, and a clean room space can be created.

Although the planar illumination device according to this embodiment includes the diffusion panel 102 and the high reflection sheet 104, these configurations can be omitted as appropriate. When the planar lighting device does not have the diffusion panel 102, the light emitting surface of the planar lighting device 100 may match the light emitting surface of the light guide plate 103, or may match the light emitting surface of another configuration. . If the planar illumination device does not have the high-reflectance sheet 104, for example, the reflection-side surface (reflection surface) of the light guide plate 103 may be coated with a reflective material or the like. In this specification, the structure including the high-reflection sheet 104 and the reflective material may be referred to as a "reflection layer".

Next, a schematic configuration of a planar lighting device 700 according to a second embodiment of the present invention will be described with reference to FIGS. 9 to 11. FIG.

FIG. 9 is a perspective view of the planar lighting device 700 attached to the wall surface 800 as viewed from below. FIG. 10 is a perspective view of planar lighting device 700 removed from wall surface 800 and viewed from above. As shown in FIGS. 9 and 10, a lighting device 700 according to the present embodiment has a substantially box-like overall shape in which rectangular diffusion panels 702A and 702B are arranged inside a square ring-shaped body frame 701. there is The diffusion panel 702A is arranged on the bottom surface of the lighting device 700, and the diffusion panel 702B is arranged on the top surface of the lighting device 700. FIG. In use, illumination is provided through diffuser panels 702A and 702B.

FIG. 11 is an exploded perspective view of the planar illumination device 100. FIG. A planar illumination device 700 according to this embodiment, as shown in FIG. It comprises diffusion panels 702A, 702B, light guide plates 703A, 703B, high reflection sheets 704A, 704B, sponges 705A, 705B, and chassis 706A, 706B.

The body frame 701 is configured in a substantially square annular shape in this embodiment.

The main body frame 701 has an extending portion 711A extending inward from the lower end of the main body frame 701, and is provided above the extending portion 711A and extends inward from the inner peripheral surface of the main body frame 701. and an extension portion 712A. The extending portion 711A and the extending portion 712A hold the diffusion panel 702A, the light guide plate 703A, the high reflection sheet 704A, the sponge 705A, and the chassis 706A.

In addition, the body frame 701 includes an extension portion 711B extending inward from the upper end of the body frame 701, and an extension portion 711B provided below the extension portion 711B and extending inward from the inner peripheral surface of the body frame 701. and an extension portion 712B that protrudes. The extensions 711B and 712B hold the diffusion panel 702B, the light guide plate 703B, the high reflection sheet 704B, the sponge 705B, and the chassis 706B.

3, light-emitting modules 210A and 210B are provided inside the front portion of the body frame 701 (in the direction away from the wall surface 800).

The light-emitting module 210A is provided, for example, between the extending portion 711A and the extending portion 712A, and includes a plurality of light-emitting elements horizontally arranged in a row along the front portion of the body frame 701 . The plurality of light emitting elements are arranged along a portion of the outer circumference (one side on the front side) of the light guide plate 703A, and irradiate the side surface of the light guide plate 703A with light.

The light-emitting module 210B is provided, for example, between the extending portion 711B and the extending portion 712B, and includes a plurality of light-emitting elements horizontally arranged in a line along the front portion of the body frame 701 . The plurality of light emitting elements are arranged along a portion of the outer circumference (one side on the front side) of the light guide plate 703B, and irradiate the side surface of the light guide plate 703B with light.

Diffusion panels 702A and 702B are formed in a substantially rectangular shape, but in other respects, they are configured in substantially the same manner as the diffusion panel 102 according to the first embodiment.

Although the light guide plates 703A and 703B are formed in a substantially rectangular shape, other points are substantially the same as the light guide plate 103 according to the first embodiment.

Although the high reflection sheets 704A and 704B are formed in a substantially rectangular shape, other points are substantially the same as the high reflection sheet 104 according to the first embodiment.

Although the sponges 705A and 705B are formed in a substantially rectangular shape, they are configured in substantially the same manner as the sponge 105 according to the first embodiment in other respects.

The chassis 706A, 706B are made of a highly rigid material such as metal, and as shown in FIG. 11, are formed in a substantially square annular shape with openings 706Aa, 706Ba at the center. The chassis 706A sandwiches the diffusion panel 702A, the light guide plate 703A, the high reflection sheet 704A, and the sponge 705A together with the extending portion 711A of the body frame 701. FIG. The chassis 706B sandwiches the diffusion panel 702B, the light guide plate 703B, the high reflection sheet 704B, and the sponge 705B together with the extending portion 711B of the body frame 701. FIG.

The space partitioned by the chassis 706A, 706B and the body frame 701 accommodates the controller 410, wiring, and the like. The control unit 410 is configured almost similarly to the control unit 400 according to the first embodiment. The control unit 410 includes a radio wave transmitting/receiving unit (not shown) like the control unit 400 according to the first embodiment. Antenna 413a of this radio wave transmitting/receiving unit is provided at a position corresponding to openings 706Aa and 706Ba provided in chassis 706A and 706B, and is provided at a constant distance from chassis 706A and 706B. However, when the chassis 706A, 706B are made of a material other than metal, and radio waves are not blocked by the chassis 706A, 706B, the chassis 706A, 706B and the antenna 413a may be provided close to each other.

The holding member 707 includes a wall mounting portion 707a that can be mounted on the wall surface 800 (FIG. 9), an attitude adjusting portion 707b that can adjust the attitude of the body frame 701 with respect to the wall mounting portion 707a, and the attitude adjusting portion 707b attached to the body frame 701. Fixable fixing portions 707c and 707d are provided.

In the illustrated example, the body frame 701 and the chassis 706A, 706B are configured in a substantially rectangular annular shape, and include diffusion panels 702A, 702B, light guide plates 703A, 703B, high reflection sheets 704A, 704B, and a sponge 705A. , 705B are formed in a substantially rectangular shape. That is, these configurations have a shape along a rectangle. However, these configurations may have a shape along a circle or an ellipse, or they may have other shapes.

Also in this embodiment, as in the first embodiment, it is possible to form the frame into a shape without projections, thereby realizing a brightness suitable for the main lighting of the living room and creating a stylish living room space.

In addition, in the above-described first and second embodiments, an annular chassis was exemplified as a configuration for supporting the radio wave transmitting/receiving unit so as not to shield radio waves. Various configurations can be adopted as long as the configuration can support the radio wave transmitting/receiving unit so that radio waves are not shielded in space. For example, a configuration in which the radio wave transmitting/receiving unit is directly fixed inside the frame, or a configuration in which the radio wave transmitting/receiving unit is fixed to a supporting member or the like extending radially inward from the frame may be employed.

In addition, the configuration according to this embodiment is merely an example, and the specific configuration can be changed as appropriate.

DESCRIPTION OF SYMBOLS 100... Planar illumination apparatus 101... Main body frame 102... Diffusion panel 103... Light guide plate 104... High reflection sheet 105... Sponge 106... Chassis 107... Holding member 201... Light emitting element 202... Flexible print Substrate 203 First terminal 204 Second terminal 400 Control section 403 Radio wave transmitting/receiving section 404 Third terminal 405 Fourth terminal 406 Voltage control section 407 Signal control section.

Claims (6)

a holding member attached to an adapter provided on the mounting surface;
a first light guide plate having an upper surface and a lower surface, the lower surface being arranged to serve as a light emitting surface;
a plurality of first light emitting elements arranged along the outer circumference of the first light guide plate;
a first reflective layer provided along the top surface of the first light guide plate;
a chassis provided at a position farther from the light emitting surface of the first light guide plate than the first reflective layer;
a radio wave receiving unit having an antenna;
a control unit that controls the voltage supplied to the plurality of first light emitting elements according to the output signal of the radio wave receiving unit;
The chassis is formed in a substantially annular shape with an opening in the center,
The radio wave receiving unit and the control unit are provided on the chassis so as to be positioned radially outside the adapter when the holding member is attached to the adapter,
The antenna of the radio wave receiving unit is provided at a position corresponding to the opening of the chassis,
Further comprising a body frame attached to the holding member,
the first light guide plate, the first reflective layer and the chassis are arranged between the holding member and the body frame,
The radio wave receiving unit and the control unit are accommodated in a space partitioned by the chassis and the inner peripheral surfaces of the body frame.
Planar lighting device. 2. The spread lighting device according to claim 1, which is configured to be attachable to a ceiling. a first light guide plate having an upper surface and a lower surface, the lower surface being arranged to serve as a light emitting surface;
a plurality of first light emitting elements arranged along the outer circumference of the first light guide plate;
a first reflective layer provided along the top surface of the first light guide plate;
a first chassis provided at a position farther from the light emitting surface of the first light guide plate than the first reflective layer;
a second light guide plate having a lower surface and an upper surface, the upper surface being arranged to serve as a light emitting surface;
a plurality of second light emitting elements arranged along the outer periphery of the second light guide plate;
a second reflective layer provided along the lower surface of the second light guide plate;
a second chassis provided at a position farther from the light emitting surface of the second light guide plate than the second reflective layer;
a radio wave receiving unit having an antenna;
a control unit that controls the voltage supplied to the plurality of first light emitting elements and the plurality of second light emitting elements according to the output signal of the radio wave receiving unit;
The first chassis and the second chassis are formed in a substantially annular shape with an opening in the center,
The radio wave receiving unit and the control unit are provided between the first chassis and the second chassis,
An antenna of the radio wave receiving unit is provided at a position corresponding to openings of the first chassis and the second chassis. 4. The spread lighting device according to claim 3 , which is configured to be attachable to a wall surface. 5. The first reflective layer is a reflective sheet provided on the upper surface of the first light guide plate, or a reflective material applied to the upper surface of the first light guide plate . The planar lighting device described. The planar illumination device according to any one of claims 1 to 5 , wherein the radio wave receiving section outputs a signal to the control section according to radio waves of 300 MHz to 3.00 GHz.

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