JP2008028269A - Solid state light emitting element, illuminator, and image display unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid state light emitting element wherein, even if a light emission area is increased, high speed drive is made possible without upsizing a driving circuit, and even if short circuit occurs on part of a semiconductor layer, it is avoided that the entire of a light emission surface is prevented from failure in emitting light. <P>SOLUTION: The solid state light emitting element includes a semiconductor layer 1 formed into a pn junction, and has a surface electrode 2 disposed on a rear surface side of the semiconductor layer 1, a dispersion electrode 3 disposed on a surface side, and a surface emitting light source provided on the surface side. In the solid state light emitting element, the dispersion electrode 3 is divided into a plurality of portions separated from each other. A plurality of driving circuits are correspondingly connected with the respective divided portions of the dispersion electrode 3, and a power supply is supplied to each driving circuit to hereby construct an illuminator. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention includes a solid-state light-emitting element having a PN-junction semiconductor layer, an illuminating device having the solid-state light-emitting element and illuminating a spatial light modulation element in an image display device and the like, and such an illuminating device. The present invention relates to an image display device.

  2. Description of the Related Art Conventionally, there has been proposed an image display apparatus that includes a spatial light modulation element, illuminates the spatial light modulation element with an illuminating device, and forms an image of modulated light that has passed through the spatial light modulation element. In such an image display device, the spatial light modulation element displays a display image and modulates illumination light in accordance with the image. The modulated light modulated by the spatial light modulator is imaged by an imaging optical system, and displays an image on a screen, for example.

  In such an illuminating device for an image display device, a light source using a solid light emitting element as described in Patent Document 1 has been proposed. A solid light emitting element is a light emitting diode (LED), a semiconductor laser diode (LD), an electroluminescent element (EL), or the like.

  As such a solid-state light emitting device, as shown in FIG. 6, a surface electrode 102 is disposed on the back surface side of the PN-bonded semiconductor layer 101, a ladder electrode 103 is disposed on the front surface side, and the surface side is a surface. A light emitting light source has been proposed. In such a solid-state light emitting device that performs surface light emission, the surface-side ladder electrode 103 is a single electrode as a whole, as shown in FIG. Connected to the drive circuit.

  The solid-state light emitting element emits light by supplying power to the semiconductor layer 101 via the ladder electrode 103 and the surface electrode 102 by a driving circuit.

JP 7-66455 A

  In the image display apparatus as described above, it is desired to display a high-luminance image by illuminating the spatial light modulation element with a higher luminance, and the output of the light source is increased. Yes. For this reason, in the case of using the conventional solid state light emitting device as described above, it is desired to increase the light emitting area.

  In the solid state light emitting device, when the light emitting area is increased, the drive current also tends to increase. Therefore, in a solid state light emitting device with an increased light emitting area, particularly when high speed driving such as high speed pulse driving is performed, high speed driving is performed with a large current, and thus the power supply and driving circuit must be enlarged. When the power supply and the drive circuit are increased in size, the downsizing of the apparatus configuration is hindered and the manufacturing cost is increased.

  Further, in the conventional solid-state light emitting device, if a short circuit occurs in a part of the semiconductor layer 101 for some reason, the current between the ladder-shaped electrode 103 and the surface electrode 102 is concentrated on this short-circuited portion, so that the entire light emitting surface Stops emitting light.

  Therefore, the present invention is proposed in view of the above-described circumstances, and even when the light emitting area is increased, high-speed driving is possible without increasing the size of the driving circuit, and a part of the semiconductor layer is provided. Provides a solid-state light-emitting element that prevents the entire light-emitting surface from emitting light even if a short circuit occurs in the light source, and increases the light-emitting area without increasing the size of the drive circuit by using such a solid-state light-emitting element It is an object of the present invention to provide an illuminating device that can be used, and to provide an image display device using such an illuminating device.

  In order to solve the above-described problems and achieve the object, an illumination device according to the present invention has any one of the following configurations.

[Configuration 1]
A solid-state light emitting device according to the present invention is formed on a semiconductor layer in which a plurality of types of semiconductors are stacked via a bonding surface, a dispersed electrode formed on one surface of the semiconductor layer, and the other surface of the semiconductor layer. One surface side on which the dispersed electrode is formed by emitting light in the vicinity of the bonding surface by applying a forward voltage between the surface electrode and the dispersed electrode and energizing the semiconductor layer between the surface electrode and the dispersed electrode. A solid-state light-emitting element serving as a surface-emitting light source that is emitted from the outside to the outside, wherein the dispersion electrode is an electrode that is divided into a plurality of parts and these parts are separated from each other.

[Configuration 2]
In the lighting device according to the present invention, a plurality of types of semiconductors are stacked via a bonding surface, a dispersed electrode is formed on one surface and divided into a plurality of parts, and a surface electrode is formed on the other surface. A surface emitting light source having a semiconductor layer and applying a forward voltage between the surface electrode and the dispersion electrode to emit light in the vicinity of the junction surface and to emit this light to the outside from one surface side where the dispersion electrode is formed; A solid-state light emitting device, a plurality of drive circuits connected to each separated portion of the dispersion electrode, and a power supply unit that supplies power to each drive circuit. The solid-state light emitting element emits surface light by supplying power to each part.

[Configuration 3]
The image display device according to the present invention includes first to third illumination devices that emit illumination light of any one of the three primary colors, and the first illumination device illuminated with illumination light from the first illumination device. A spatial light modulation element, a second spatial light modulation element illuminated by illumination light from the second illumination device, and a third spatial light modulation element illuminated by illumination light from the third illumination device A color synthesizing element that synthesizes the modulated light that has passed through each spatial light modulation element, and an imaging optical system that receives the modulated light that has passed through the color synthesizing element and forms an image of each spatial light modulation element. The first to third lighting devices are
A plurality of types of semiconductors are stacked via a bonding surface, a dispersed electrode is formed on one surface and divided into a plurality of parts and separated, and the surface electrode is formed on the other surface. A solid-state light-emitting element serving as a surface-emitting light source that applies a forward voltage between the first electrode and the dispersion electrode to emit light near the bonding surface and emits the light to the outside from one surface side where the dispersion electrode is formed; A plurality of drive circuits connected corresponding to the separated parts, and feedback means for detecting the light emission state of the solid state light emitting element and controlling each drive circuit based on the detection result, In each lighting device, each drive circuit feeds power to each corresponding part of the dispersion electrode to cause the solid-state light emitting element to emit light, and each feedback unit in each lighting device balances the amount of illumination light from each lighting device. Maintained , It is characterized in maintaining the white balance of a display image.

  In the solid state light emitting device according to the present invention having the configuration 1, since the dispersion electrode is an electrode that is divided into a plurality of parts and these parts are separated from each other, the drive current supplied to these parts is It decreases in inverse proportion to the number of divisions of the dispersion electrode. Therefore, if a plurality of drive circuits are connected corresponding to the divided portions of the dispersion electrode, high-speed driving is possible without increasing the size of these drive circuits.

  Even if a short circuit occurs for some reason in a part of the semiconductor layer, since the dispersed electrode is divided into a plurality of parts, the current between the dispersed electrode and the surface electrode does not concentrate on the shorted part, and light emission The entire surface does not stop emitting light.

  In the illuminating device according to the present invention having the configuration 2, the solid-state light emitting device having the configuration 1, the plurality of drive circuits connected corresponding to the separated portions of the dispersion electrode, and supplying power to each drive circuit A power supply unit that supplies power to each corresponding part of the dispersion electrode by each drive circuit and causes the solid-state light emitting element to emit light, so that the drive current supplied to each divided part of the dispersion electrode Decreases in inverse proportion to the number of divisions of the dispersion electrode, and high-speed driving is possible without increasing the size of the drive circuit.

  In the image display device according to the present invention having the configuration 3, the first to third illumination devices detect the configuration of the configuration 2 and the light emission state of the solid state light emitting element, and control each drive circuit based on the detection result. Therefore, high-speed driving is possible without increasing the size of the drive circuit.

  Further, in this image display device, each feedback means in each lighting device maintains the light quantity balance of the illumination light from each lighting device and maintains the white balance of the display image, so for some reason in part of the semiconductor layer Even when a short circuit occurs and the amount of light decreases, the white balance of the display image is maintained well.

  That is, according to the present invention, even if the light emitting area is increased, high-speed driving is possible without increasing the size of the drive circuit, and even if a short circuit occurs in a part of the semiconductor layer, the entire light emitting surface does not emit light. And a lighting device capable of increasing the light emitting area without increasing the size of the drive circuit by using such a solid light emitting element. An image display device using such an illumination device can be provided.

  Hereinafter, a solid light emitting element according to the present invention, an illumination device using the solid light emitting element, and an image display device using the illumination device will be described in detail.

[Embodiment of solid-state light emitting device]
FIG. 1 is a side view showing a configuration of a solid state light emitting device according to the present invention.

  As shown in FIG. 1, the solid-state light emitting device according to the present invention has a semiconductor layer 1 in which a plurality of types of semiconductors are stacked via a bonding surface, and a dispersion electrode 3 is formed on one surface of the semiconductor layer 1. The surface electrode 2 is formed on the other surface of the semiconductor layer 1. In this solid-state light emitting element, a forward voltage is applied between the surface electrode 2 and the dispersion electrode 3 and the semiconductor layer 1 is energized to emit light in the vicinity of the bonding surface, thereby becoming a surface emitting light source. This solid state light emitting device is configured on the silicon substrate 4 with the other surface facing down, and is fed to the semiconductor layer 1 via bonding wires 5. In addition, this solid-state light-emitting element has a reflective film disposed on the other surface side of the semiconductor layer 1 and is configured as a so-called high-brightness LED.

  The junction surface in the semiconductor layer 1 is generally a PN junction. In this solid state light emitting device, electrons and holes injected into the semiconductor layer 1 from the surface electrode 2 and the dispersion electrode 3 flow in different energy bands (conduction band and valence band), and are forbidden bands near the junction surface. Recombine beyond. When electrons and holes are recombined, energy substantially corresponding to the forbidden band (band gap) is emitted as photons, that is, light, and emits light.

  In addition, although the junction surface in the semiconductor layer 1 is generally a PN junction, a double hetero junction structure or a quantum well junction structure may be used in order to increase the light emission efficiency. Such a semiconductor layer 1 is manufactured by stacking thin films on a substrate by chemical vapor deposition.

  In this solid state light emitting device, light is emitted from the bonding surface of the semiconductor layer 1 to both sides. Light emitted from the semiconductor layer 1 to one surface (hereinafter referred to as a surface portion) is emitted as it is from the surface side of the semiconductor layer 1 to the outside. Light emitted from the semiconductor layer 1 to the other surface (hereinafter referred to as a back surface portion) side is reflected by the reflective film, passes through the semiconductor layer 1 and is emitted to the front surface side. Further, the incident light from the outside to the semiconductor layer 1 is transmitted through the semiconductor layer 1, reflected by the reflective film on the back surface side, transmitted through the semiconductor layer 1 again, and emitted to the front surface side. In this way, in this solid state light emitting device, the light that has been lost due to light absorption on the back surface side in the conventional LED is reflected and emitted to the outside from the front surface side, so that high brightness is achieved. Since the semiconductor layer 1 transmits light having a wavelength emitted from the semiconductor layer 1, incident light in this wavelength band is transmitted through the semiconductor layer 1 and reflected by the reflective film on the back surface side. Become.

  The semiconductor layer 1 of the solid state light emitting device has a rectangular shape of 2 mm × 6 mm, for example. The material of the semiconductor layer 1 of such a solid state light emitting device is AlGaAs, AlGaInP, GaAsP, etc. for red light emission, InGaN, AlGaInP, etc. for green light emission, and InGaN for blue light emission. These InGaN-based materials are generally formed by epitaxial growth on a sapphire substrate. The reflective film is formed, for example, by peeling the semiconductor from the sapphire substrate by laser lift-off and planarizing the P-type semiconductor surface. This reflective film can be formed directly on the back surface of the semiconductor by sputtering or the like.

  FIG. 2 is a plan view showing the configuration of the solid state light emitting device according to the present invention.

  As shown in FIG. 2, the dispersion electrode 3 is divided into a plurality of parts, and these parts are separated from each other. The divided portions of the dispersion electrode 3 are connected to the bonding pattern 6 via bonding wires 5. The bonding pattern 6 is divided and separated into a number corresponding to the number of each divided part of the dispersion electrode 3 so that the divided parts of the dispersion electrode 3 do not conduct each other.

  This solid-state light emitting element is used by being connected to a separate drive circuit corresponding to each of the divided parts of the dispersion electrode 3 via the bonding pattern 6 and the bonding wire 5. Each drive circuit can be supplied with power from the same power supply unit.

  In this solid state light emitting device, if a current of M (A) is passed through the entire solid state light emitting device, if the number of divisions is n for one of the divided portions of the dispersion electrode 3, [M / n] The current of (A) may be passed. For example, when a current of 10 A is applied to the entire solid state light emitting device, if the number of divisions of the dispersion electrode 3 is 5, if a current of 2 A is applied to one of the divided parts of the dispersion electrode 3, Good. Therefore, in this solid-state light emitting device, when high-speed driving such as high-speed pulse driving is performed, the load on the driving circuit is reduced, and the device configuration can be downsized and the cost can be reduced.

  Further, in this solid state light emitting device, even if a short circuit occurs in a part of the semiconductor layer 1 for some reason, the current between the dispersive electrode 3 and the surface electrode 2 does not concentrate on this short circuit part. Although the amount decreases, the entire light emitting surface does not stop emitting light.

[Embodiment of Lighting Device]
FIG. 3 is a block diagram showing the configuration of the illumination device according to the present invention.

  As shown in FIG. 3, the lighting device according to the present invention has the solid-state light emitting element 10 according to the present invention described above, and is connected corresponding to each separated part of the dispersion electrode 3 of the solid-state light emitting element 10. A plurality of drive circuits 7 and a power supply unit 8 for supplying power to each drive circuit 7 are provided.

  In this illuminating device, each drive circuit 7 supplies power to each corresponding portion of the dispersion electrode 3 to cause the solid-state light emitting element 10 to emit light. That is, the power supply unit 8 supplies power to each drive circuit 7 by direct current. Each drive circuit 7 supplies CW or a high-speed pulse current to the separated portion of the connected dispersion electrode 3 to drive the solid-state light emitting element 10 at high speed. Thus, in this illumination device, since the power supply unit 8 is not pulse-driven, high-speed pulse driving of several kHz is possible.

  In this illuminating device, since the solid-state light-emitting element 10 can be pulse-driven at high speed, the thermal resistance of the solid-state light-emitting element 10 resulting from the pulse drive is so low that it can be ignored, and a larger current can be supplied. High luminance light emission can be performed.

  Further, in this lighting device, if a current of M (A) is passed through the entire solid-state light emitting device 10, if the number of divisions is n for one of the divided portions of the dispersion electrode 3, [ M / n] (A) may be supplied, and when high-speed driving such as high-speed pulse driving is performed, the load on each driving circuit 7 is reduced, and the size and cost of the apparatus can be reduced. . That is, in this lighting device, since each drive circuit 7 is driven in parallel, the amount of current per drive circuit 7 is reduced, and the manufacturing cost can be reduced and the noise can be reduced.

  Further, in this lighting device, even if a short circuit occurs for some reason in a part of the semiconductor layer 1 of the solid state light emitting device 10, the current between the dispersion electrode 3 and the surface electrode 2 does not concentrate on this short circuit part. The overall light emission amount is reduced, but the entire light emitting surface does not stop emitting light.

  And in this illuminating device, you may provide the feedback means which detects the light emission state of the solid light emitting element 10, and controls each drive circuit 7 based on this detection result. This feedback means detects the amount of current supplied to the photodetector 11 that detects the amount of light emitted from the solid state light emitting element 10, the temperature detector 12 that detects the temperature of the solid state light emitting element 10, or the solid state light emitting element 10. And a control circuit 9 to which a detection signal from the detector is sent.

  The control circuit 9 generates a control signal based on the detection signal sent from the detector, and controls each drive circuit 7 by this control signal. By this feedback means, the amount of emitted light, the emission wavelength (emission color), the temperature of the solid light emitting element 10, or the amount of current supplied to the solid light emitting element 10 is stably maintained at a predetermined value. The Rukoto.

  FIG. 4 is a side view showing a method of using the lighting device according to the present invention.

  This illuminating device can be used, for example, as an illuminating device for an image display device. In this case, as shown in FIG. 4, the illumination light emitted from the solid-state light emitting element 10 of the illuminating device is used as illumination optics. The spatial light modulator 15 is illuminated via the system 14. Then, the modulated light that has passed through the spatial light modulator 15 is imaged by an imaging optical system (not shown), and image display is performed.

In such an image display device, in order to increase the brightness of the display image, it is necessary to increase the amount of illumination light emitted from the illumination device. The illumination light emitted from the solid state light emitting device is about 120 lm (lumen) per area (mm ² ) of the light emitting surface of the solid state light emitting device, and it is necessary to increase the area of the light emitting surface in order to increase the amount of illumination light. There is. However, as described above, when the light emitting area is increased in the solid state light emitting device, it is necessary to drive with a large current, and the power source and the driving circuit must be enlarged. The driving current of the solid state light emitting element is, for example, about 1.4 A per area (mm ² ) of the light emitting surface. If the area of the light emitting surface is 10 mm ² , the driving current becomes a large current of 14 A.

  In the lighting device according to the present invention, as described above, since a plurality of drive circuits 7 are used in parallel, the amount of current per one drive circuit 7 is reduced, and the amount of current in each drive circuit 7 is increased. Therefore, the light emitting area of the solid state light emitting device can be increased, and the brightness of the display image can be increased.

[Embodiment of Image Display Device]
FIG. 5 is a plan view showing the configuration of the image display apparatus according to the present invention.

  As shown in FIG. 5, the image display device according to the present invention is a first unit that emits illumination light of any one of the three primary colors (R (red), G (green), and B (blue)). Thru / or the third lighting device. Each of these illumination devices is the illumination device according to the present invention described above, and is configured to include the solid-state light emitting elements 10R, 10G, and 10B, respectively. This image display device includes a first spatial light modulator 15R that is illuminated by illumination light from the first illumination device, and a second spatial light modulator 15G that is illuminated by illumination light from the second illumination device. And a third spatial light modulation element 15B that is illuminated by illumination light from the third illumination device, and color-synthesizes the modulated light that has passed through these spatial light modulation elements 15R, 15G, and 15B by a color synthesis element, This is an apparatus for displaying a color image by forming an image of modulated light that has passed through a color synthesizing element by an imaging optical system.

  Each lighting device illuminates the first spatial light modulator 15R displaying a red component image with red illumination light, and the second spatial light modulator 15G displaying a green component image with green illumination light. Illuminate and illuminate the third spatial light modulator 15B displaying the blue component image with blue illumination light. Each of the spatial light modulators 15R, 15G, and 15B displays the red component, the green component, and the blue component of the display image, respectively, and polarization-modulates the illumination light according to these images. In this embodiment, each of the spatial light modulators 15R, 15G, and 15B is of a reflective type, and reflects incident illumination light by polarization modulation.

  That is, the illumination light emitted from the solid state light emitting element 10R of the red illumination device is a light pipe 16R, a collimator lens 17R, a ¼ wavelength plate 18R, a wire grid 19R, and a fly-eye lens 20R constituting the illumination optical system 14R. Then, the light passes through the field lens 21R and the polarization beam splitter 22R and enters the first reflective spatial light modulator 15R. The red illumination light is polarized and modulated in accordance with the image signal of the red component by the first reflective spatial light modulator 15R, reflected by the polarization beam splitter 22R, and converted into red modulated light as a color combining element. Is incident from one side surface to the color composition prism 23.

  Also, the illumination light emitted from the solid state light emitting element 10G of the green illumination device is a light pipe 16G, a collimator lens 17G, a quarter wavelength plate 18G, a wire grid 19G, and a fly's eye lens 20G constituting the illumination optical system 14G. Then, the light passes through the field lens 21G and the polarization beam splitter 22G and enters the second reflective spatial light modulator 15G. The green illumination light is polarized and modulated by the second reflective spatial light modulator 15G according to the image signal of the green component, reflected, reflected by the polarization beam splitter 22G, and converted into green modulated light as the color synthesis prism 23. From the rear surface.

  The illumination light emitted from the solid state light emitting element 10B of the blue illumination device is converted into a light pipe 16B, a collimator lens 17B, a quarter-wave plate 18B, a wire grid 19B, and a fly-eye lens 20B that constitute the illumination optical system 14B. Then, the light passes through the field lens 21B and the polarization beam splitter 22B and enters the third reflective spatial light modulator 15B. The blue illumination light is polarization-modulated and reflected by the third reflective spatial light modulator 15B in accordance with the image signal of the blue component, reflected by the polarization beam splitter 22B, and reflected as the blue modulated light by the color synthesis prism 23. From the other side.

  The red, green, and blue modulated lights incident on the color synthesis prism 23 are color-combined, emitted to the front surface of the color synthesis prism 23, and incident on a projection lens 24 serving as an imaging optical system. The projection lens 24 projects the modulated light of each color on a screen (not shown), enlarges the image, and displays an image.

  In this image display device, as described above, each lighting device detects a light emitting state of each solid state light emitting element 10R, 10G, 10B, and a detector serving as feedback means for controlling each driving circuit based on the detection result. And a control device. And in each illuminating device in this image display apparatus, each control apparatus maintains the light quantity balance of the illumination light radiate | emitted from each illuminating device, and maintains the white balance of a display image.

  That is, in this image display device, even if a short circuit occurs for some reason in a part of the solid state light emitting elements 10R, 10G, and 10B of any of the lighting devices, the control device of each lighting device is reduced. Since the light quantity balance of the illumination light emitted from each illumination device is maintained, the white balance of the display image is not lost, and the display of the image with the white balance maintained can be continued.

It is a side view which shows the structure of the solid light emitting element which concerns on this invention. It is a top view which shows the structure of the solid light emitting element which concerns on this invention. It is a block diagram which shows the structure of the illuminating device which concerns on this invention. It is a side view which shows the usage method of the illuminating device which concerns on this invention. It is a top view which shows the structure of the image display apparatus which concerns on this invention. It is a side view which shows the structure of the conventional solid light emitting element. It is a top view which shows the structure of the conventional solid light emitting element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor layer 2 Surface electrode 3 Dispersed electrode 4 Board | substrate 5 Bonding wire 6 Bonding pattern 7 Drive circuit 8 Power supply part 9 Control apparatus 10 Solid state light emitting element 10R Solid state light emitting element 10G Solid state light emitting element 10B Solid state light emitting element 14 Illumination optical system 14R Illumination optical system 14G illumination optical system 14B illumination optical system 15 spatial light modulator 15R first spatial light modulator 15G second spatial light modulator 15B third spatial light modulator 23 color synthesis prism 24 projection lens

Claims (3)

A semiconductor layer in which a plurality of types of semiconductors are stacked via a bonding surface; a dispersion electrode formed on one surface of the semiconductor layer; and a surface electrode formed on the other surface of the semiconductor layer. Then, by applying a forward voltage between the surface electrode and the dispersion electrode and energizing the semiconductor layer, light is emitted in the vicinity of the bonding surface, and this light is one surface side on which the dispersion electrode is formed. A solid-state light-emitting element serving as a surface-emitting light source to be emitted from the outside,
The dispersion electrode is an electrode which is divided into a plurality of parts, and each of these parts is separated from each other. A semiconductor layer in which a plurality of types of semiconductors are stacked via a bonding surface, a dispersed electrode is formed by dividing into a plurality of parts and separated on one surface, and a surface electrode is formed on the other surface. Solid-state light emission serving as a surface-emitting light source that applies a forward voltage between the electrode and the dispersion electrode to emit light in the vicinity of the bonding surface and emits the light to the outside from one surface side where the dispersion electrode is formed Elements,
A plurality of drive circuits connected corresponding to the separated portions of the dispersion electrode;
A power supply unit that supplies power to each of the drive circuits,
The lighting device, wherein each driving circuit feeds power to corresponding portions of the dispersion electrode to cause the solid-state light emitting element to emit light. First to third illumination devices each emitting illumination light of one of the three primary colors different from each other;
A first spatial light modulation element illuminated by illumination light from the first illumination device;
A second spatial light modulation element illuminated by illumination light from the second illumination device;
A third spatial light modulation element illuminated by illumination light from the third illumination device;
A color synthesizing element that color-synthesizes the modulated light that has passed through each of the spatial light modulation elements;
An imaging optical system that receives the modulated light that has passed through the color synthesis element and forms an image of each of the spatial light modulation elements; and
In the first to third lighting devices, a plurality of types of semiconductors are stacked via a bonding surface, a dispersed electrode is formed on one surface and divided into a plurality of parts, and a surface electrode is formed on the other surface. A semiconductor layer is formed and a forward voltage is applied between the surface electrode and the dispersion electrode to emit light in the vicinity of the bonding surface, and this light is emitted to the outside from one surface side where the dispersion electrode is formed. A solid state light emitting device to be a surface emitting light source, a plurality of drive circuits connected to each separated portion of the dispersion electrode, and a light emitting state of the solid state light emitting device, and based on the detection result, Feedback means for controlling each drive circuit,
In each of the lighting devices, each of the driving circuits feeds power to each corresponding part of the dispersion electrode to cause the solid-state light emitting element to emit light,
Each feedback means in each lighting device maintains the light quantity balance of the illumination light from each lighting device, and maintains the white balance of the display image.

Images