JP2006236701A - Backlight device and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a thin liquid crystal display having low power consumption that can reduce an uneven color and luminance irregularities. <P>SOLUTION: The liquid crystal display comprises a light source consisting of a plurality of light-emitting diodes 21 for emitting at least red, green, and blue light; an optical member 30 for covering the light emission direction of the plurality of light-emitting diodes 21 that are light sources and controlling the radiation angle distribution of colored light emitted from each light-emitting diode 21; a diffusion reflection means 41DR for diffusing and reflecting the colored light that enters the optical member 30 and is guided while being totally reflected repeatedly; and a diffusion plate 141 that diffuses the colored light emitted from the optical member 30 for planar emission. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display (LCD) including a backlight device, and more particularly to a backlight device that is reduced in thickness while reducing color unevenness, and a liquid crystal display device including the backlight device.

  Instead of CRT (Cathode Ray Tube), which has been used for many years since the start of television broadcasting, it has been made very thin, such as a liquid crystal display (LCD) and a plasma display (PDP). Television receivers have been devised and put into practical use. In particular, liquid crystal display devices using a liquid crystal display panel can be driven with low power consumption, and it is considered that the liquid crystal display device will be used at an accelerated pace due to the price reduction of large liquid crystal display panels. It is a display device that can be expected to develop further.

  In the liquid crystal display device, a backlight method in which a color image is displayed by illuminating a transmissive liquid crystal display panel provided with a color filter from the back side with a backlight device is mainly used. As a light source of a backlight device, a fluorescent lamp such as a CCFL (Cold Cathode Fluorescent Lamp) that emits white light using a fluorescent tube is often used.

  In addition, since the CCFL encloses mercury in a fluorescent tube and thus has an adverse effect on the environment, a light emitting diode (LED) is promising as a light source of a backlight device that replaces the CCFL (for example, Patent Document 1).

  With the development of blue light-emitting diodes, light-emitting diodes that emit red, green, and blue light, which are the three primary colors of light, have been prepared, and red light, green light, and blue light emitted from these light-emitting diodes have been prepared. By mixing colors, white light with high color purity can be obtained. Therefore, by using this light emitting diode as the light source of the backlight device, the color purity of the color light via the liquid crystal display panel is increased, so that the color reproduction range can be greatly expanded compared with the CCFL.

  As a light-emitting diode used as a light source of a backlight device, a light-emitting diode using a high-power light-emitting diode (LED) chip is effective. By using this light-emitting diode, the luminance of the backlight device is greatly improved. Can do.

Japanese Patent Laid-Open No. 7-191311

  Backlight devices that emit illumination light for illuminating a liquid crystal display panel are roughly classified into two types, a direct type and an edge light type, depending on the arrangement position of the light source. The direct type is a backlight device in which a light source is arranged directly under the back side of the liquid crystal display panel, and the side edge type is a light guide plate that guides light directly under the back side of the liquid crystal display panel. This is a type of backlight device in which a light source is disposed on the side surface of the backlight device.

  Compared to the edge light type backlight device, the direct type backlight device does not require a light guide plate, so the number of parts is reduced and the manufacturing cost can be reduced. In particular, when a CCFL is used as a light source, the CCFL itself emits white light, so that the backlight device does not require a thickness for color mixing, and thus a very thin liquid crystal display device can be configured. it can.

  However, when a light emitting diode that emits red light, green light, and blue light, which are the three primary colors of light, is used as the light source of the backlight device, in order to mix these three primary color lights into white light, a liquid crystal display is used. It is necessary to secure a sufficient distance to the diffusion plate arranged in front of the panel.

  Specifically, since the light emitting diodes that emit the three primary colors are each packaged, even if they are collected and arranged in one place in order to improve color mixing, the emitted three primary colors are emitted on the diffusion plate. In this case, the colors are not completely mixed, and the closer the distance to the diffusion plate, the more prominent it becomes. When the liquid crystal display panel is illuminated using white light with uneven color, which is insufficiently mixed with the three primary colors, as illumination light, the image displayed on the liquid crystal display panel also becomes an image in which color expression is not appropriately performed.

  Therefore, in order to widen the color reproduction range, if a light emitting diode that emits three primary colors is used as a light source and a direct type backlight device is configured, it is necessary to increase the thickness of the backlight device, which obstructs thinning of the liquid crystal display device. Will end up.

In addition, if the backlight device is given a thickness and sufficient space for diffusion is not secured, the light emitted from the light-emitting diodes is not diffused throughout the backlight device, and the brightness at the position immediately above the light-emitting diodes is arranged. As a result, the luminance becomes uneven.
As a means for solving these problems, color unevenness and brightness unevenness can be solved by using a light guide plate without increasing the thickness of the device. However, when the light guide plate is used, there is a possibility that light that is repeatedly reflected in the light guide plate and does not come out of the light guide plate is generated, resulting in a decrease in luminance.

  As described above, the reduction in luminance and the suppression of color unevenness and luminance unevenness are in a trade-off relationship with each other in reducing the thickness of the backlight device, and it is very difficult to solve both simultaneously.

  Therefore, the present invention has been devised to solve the above-described problems, and uses a light emitting diode that emits light of three primary colors to broaden the color reproduction range and to illuminate a liquid crystal display panel. An object of the present invention is to provide a backlight device that can reduce brightness reduction, color unevenness, and brightness unevenness, and can be thinned, and a liquid crystal display device using the backlight device.

  To achieve the above object, a backlight device according to the present invention emits at least red light, green light, and blue light in a backlight device that illuminates a transmissive liquid crystal display panel with white light from the back side. A light source composed of a plurality of light emitting diodes, an optical member that covers the light emission direction of the plurality of light emitting diodes that are the light sources, and that controls the emission angle distribution of the colored light emitted from each of the light emitting diodes; A diffusive reflecting means for diffusing and reflecting the colored light incident and guided while repeating total reflection, and a diffusion plate for diffusing the colored light emitted from the optical member to emit planar light. .

  In order to achieve the above object, a liquid crystal display device according to the present invention is a liquid crystal display device comprising a transmissive liquid crystal display panel and a backlight device that illuminates the liquid crystal display panel with white light from the back side. The backlight device covers a light emission direction of a plurality of light emitting diodes that emit at least red light, green light, and blue light, and a plurality of light emitting diodes that are the light sources, and is emitted from each of the light emitting diodes. An optical member that controls the radiation angle distribution of the colored light, diffuse reflection means that diffuses and reflects the colored light that enters the optical member and is guided while repeating total reflection, and the colored light emitted from the optical member And a diffuser plate that diffuses the light and emits light in a planar manner.

  The present invention controls the radiation angle distribution of red light, green light, and blue light emitted from a red light emitting diode, a green light emitting diode, and a blue light emitting diode by providing an optical member such as a diffusion plate and an optical block. Is uniformly diffused over the entire surface of the liquid crystal display panel. At this time, the diffuse reflection means diffuses and reflects the color light totally reflected in the light guide plate, and increases the proportion of white light incident on the diffuser plate.

  Therefore, according to the present invention, the light use efficiency of the backlight device is increased, and even when the light emitting diode emits light with low power consumption, a desired luminance can be sufficiently secured, so that the cost can be reduced. And

  Moreover, when the liquid crystal display panel is illuminated with illumination light emitted from such a backlight device, an image with good color reproducibility can be displayed on the liquid crystal display panel. In addition, since the backlight device does not require a space necessary for color mixing with white light, the backlight device can be made much thinner than a conventional direct type backlight device. That is, it is possible to provide a thin color liquid crystal display device with high color reproducibility.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following examples, It cannot be overemphasized that it can change arbitrarily in the range which does not deviate from the summary of this invention.

  The present invention is applied to, for example, a transmissive color liquid crystal display device 100 configured as shown in FIG.

  The transmissive color liquid crystal display device 100 includes a transmissive color liquid crystal display panel 110 and a backlight device 140 provided on the back side of the color liquid crystal display panel 110. Although not shown, the transmissive color liquid crystal display device 100 includes a receiving unit such as an analog tuner and a digital tuner that receives terrestrial and satellite waves, and a video that processes a video signal and an audio signal received by the receiving unit, respectively. An audio signal output unit such as a speaker that outputs an audio signal processed by the signal processing unit, the audio signal processing unit, and the audio signal processing unit may be provided.

  In the transmissive color liquid crystal display panel 110, two transparent substrates (TFT substrate 111 and counter electrode substrate 112) made of glass or the like are arranged to face each other, and, for example, twisted nematic (TN) liquid crystal is provided in the gap. And a TFT substrate 111 and a counter electrode substrate 112 are sandwiched between two polarizing plates 131 and 132. On the TFT substrate 111, signal lines 114 arranged in a matrix, scanning lines 115, thin film transistors 116 serving as switching elements arranged at intersections of the signal lines 114 and the scanning lines 115, and pixel electrodes 117 are formed. Has been. The thin film transistor 116 is sequentially selected by the scanning line 115 and writes the video signal supplied from the signal line 114 to the corresponding pixel electrode 117. On the other hand, a counter electrode 118 and a color filter 119 are formed on the inner surface of the counter electrode substrate 112.

  The color filter 119 is divided into a plurality of segments corresponding to each pixel. For example, as shown in FIG. 2, it is divided into three segments of a red filter CFR, a green filter CFG, and a blue filter CFB which are three primary colors. The arrangement pattern of the color filter 119 includes a delta arrangement and a square arrangement, although not shown, in addition to the stripe arrangement shown in FIG.

  The configuration of the transmissive color liquid crystal display device 100 will be described again with reference to FIG. The transmissive color liquid crystal display device 100 drives the transmissive color liquid crystal display panel 110 having such a configuration in an active matrix system in a state where white light is irradiated from the back side by the backlight device 140. A desired full-color image can be displayed.

<Configuration of backlight device>
The backlight device 140 illuminates the color liquid crystal display panel 110 from the back side. As shown in FIG. 1, the backlight device 140 sufficiently diffuses light sources not shown here and light emitted from the light sources so as to suppress color unevenness and luminance unevenness while maintaining light use efficiency. In the backlight housing unit 120 in which the function to be performed is incorporated, the diffusion plate 141, the optical sheet group 145 such as the diffusion sheet 142, the prism sheet 143, and the polarization conversion sheet 144 arranged on the diffusion plate 141 are arranged. It has a configuration with.

  The diffusing plate 141 makes the luminance emitted from the surface emission uniform by internally diffusing the light emitted from the light source.

  In general, the optical function sheet group has, for example, a function of decomposing incident light into orthogonal polarization components, a function of compensating for a phase difference of light waves to achieve a wide-angle viewing angle and preventing coloring, a function of diffusing incident light, and a brightness improvement And is provided to convert the light emitted from the backlight device 140 into illumination light having optical characteristics optimal for illumination of the color liquid crystal display panel 110. . Therefore, the configuration of the optical function sheet group 145 is not limited to the diffusion sheet 142, the prism sheet 143, and the polarization conversion sheet 144 described above, and various optical function sheets can be used.

FIG. 3 shows a schematic configuration diagram in the backlight housing 120. As shown in FIG. 3, the backlight housing 120 includes a plurality of red light emitting diodes 21R that emit at least red light, green light emitting diodes 21G that emit green light, and blue light emitting diodes 21B that emit blue light. The light emitting diode unit 21 _n (n is a natural number) is used as a light source. In the following description, the red light emitting diode 21R, the green light emitting diode 21G, and the blue light emitting diode 21B are collectively referred to as the light emitting diode 21.

For example, as shown in FIG. 3, the light emitting diode units 21 _n have a longitudinal direction parallel to the horizontal direction of the backlight housing 120 and are arranged in a plurality of rows in the vertical direction in the backlight housing 120.

  A light guide plate 30 is provided in the backlight casing 120 so as to cover the light emitting diode 21. FIG. 4 shows a schematic cross-sectional view of the transmissive color liquid crystal display device 100 assembled by cutting along the XX line attached to the transmissive color liquid crystal display device 100 shown in FIG.

  As shown in FIG. 4, the light guide plate 30 is formed with, for example, a cylindrical recess 31 for storing the light emitting diode 21 on the bottom surface 30 a on the backlight housing 120 side where the light emitting diode 21 is disposed. The light guide plate 30 is formed of, for example, an acrylic resin.

  The concave portion 31 formed in the light guide plate 30 stores the light emitting diode 21 so as to cover the light emitting direction of the light emitting diode 21, so that each color light emitted from the light emitting diode 21 is incident on the light guide plate 30. become. The light guide plate 30 is an optical member provided to reduce the thickness of the backlight device 140. The light guide plate 30 is a front stage that reaches the diffusion plate 141 by making each color light emitted from the light emitting diode 21 enter and diffuse internally. The color mixture of each color light and the luminance distribution are made good.

  The light guide plate 30 can control the radiation angle distribution of the light emitted from the light emitting diode 21. For example, a desired radiation angle distribution can be obtained by adjusting the shape of the light incident surface 31A of the recess 31 that receives light emitted from the light emitting diode 21, and luminance unevenness and color unevenness can be suppressed. .

  The colored light incident on the light guide plate 30 is internally diffused while repeating total reflection in the light guide plate 30 and is guided in the light guide plate 30. At this time, only the light component having a critical angle (acrylic resin: about 42 degrees) or less out of the color light incident on the light emitting surface 30z is emitted to the diffusion plate 141. By using such a light guide plate 30, light spreads over the entire interior of the backlight housing 120, that is, the entire surface of the liquid crystal display panel 110, in front of the diffusion plate 141. Thus, the distance from the diffusion plate 141 can be shortened, and the backlight device 140 can be made thinner.

  The light guide plate 30 is provided with reflection sheets 40A and 40B on a bottom surface 30a, which is a surface on which a recess 31 is formed, and four side surfaces 30b, respectively. The reflection sheets 40A and 40B have a light reflection surface formed by vapor-depositing silver, aluminum, or the like having a high reflectance, and are adhered to the light guide plate 30 by an adhesive applied to the light reflection surface, for example. The reflection sheets 40A and 40B prevent light diffusing while guiding light in the light guide plate 30 from leaking from a surface other than the light exit surface 30z, thereby reducing the light use efficiency.

  Although the light emitting diode 21 is not described in detail, each light emitting bulb is held by a resin holder, and a pair of terminals protrude from the resin holder. Each light emitting diode 21 is provided with an optical component 21a that emits light emitted from the light source from the side surface, that is, has a directivity for emitting the main component of the emitted light in the outer peripheral direction of the light emitting bulb. So-called side emission type LEDs are used. The side-emitting LED is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2003-8068 and 2004-133391.

  FIG. 5 schematically shows a state in which the color light emitted from the light emitting diode 21 is guided within the light guide plate 30 by focusing on one light emitting diode 21. 5 indicates the state of light guided in the light guide plate 30 while repeating total reflection, and the dotted arrow indicates the state of light emitted from the light output surface 30a of the light guide plate 30. Is shown.

  The colored light emitted from the light emitting diode 21 is roughly classified into a light component that is transmitted through the light guide plate 30 and directly incident on the diffusion plate 141, and a light component that is guided through the light guide plate 30 while repeating total reflection. The In the light guided through the light guide plate 30 while repeating total reflection, there is a component that continues regular reflection without changing the reflection angle.

  Furthermore, the light component that has been totally reflected in the light guide plate 30 is a component that repeats regular reflection with no change in incident angle and reflection angle due to reflection over time, and impurities and disturbances in the light guide plate 30. The incident angle due to reflection depends on the state of the reflecting surface and the like, and the component that causes diffuse reflection that changes the reflection angle. The light that has been diffusely reflected is more likely to be incident on the light exit surface 30z of the light guide plate 30 at a critical angle or less, and when incident at a critical angle or less, the light is emitted to the diffuser plate 141. .

  That is, among the light that repeats total reflection, light that is regularly reflected while repeating total reflection is not emitted to the diffusion plate 141 while being confined inside the light guide plate 30. As described above, when the ratio of the light not emitted from the light guide plate 30 is large, the light use efficiency is extremely deteriorated.

  Therefore, the reflection sheet 40A provided on the light guide plate 30 is formed with a diffuse reflection area 41DR having a diffuse reflection action and a regular reflection area 41R having a regular reflection action as shown in FIG. The ratio of the light emitted from the light exit surface 30z of the light guide plate 30 is increased by performing diffuse reflection. At this time, if the ratio between the diffuse reflection region 41DR and the regular reflection region 41R is not appropriately adjusted, for example, if the diffusion reflection region 41DR is too much, light that is not sufficiently diffused in the light guide plate 30 is emitted from the light emitting surface 30z. From the light source, causing color unevenness and brightness unevenness.

  FIG. 7 is a view of the reflective sheet 40A viewed from the direction of arrow A shown in FIG. As shown in FIG. 7, the diffuse reflection region 41DR is formed in a stripe shape on the reflection sheet 40A. The diffuse reflection region 41DR is not limited to the stripe shape as shown in FIG. 7, but may be any shape such as a circle or a polygon.

  Further, the diffuse reflection region 41DR may be formed not only on the reflection sheet 40A but also on the reflection sheet 40B attached to the four side surfaces 30b of the light guide plate 30. Moreover, you may use combining these. Furthermore, instead of forming the diffuse reflection area 41DR on the reflection sheets 40A and 40B, the diffuse reflection area 41DR may be pattern printed on the bottom surface 40a and the four side surfaces of the light guide plate 30.

  In this way, by using the light guide plate 30 provided with the recess 31 for storing the light emitting diode 21 in the backlight casing 120, the light emitted from the light emitting diode 21 is sufficiently transmitted in the backlight casing 120. Since it can be diffused, luminance unevenness and color unevenness can be reduced. Furthermore, after the diffused reflection region 41DR for diffusing and reflecting the light emitted from the bottom surface 30a and the four side surface portions 30b of the light guide plate 30 is formed at a predetermined ratio, after being sufficiently internally diffused in the light guide plate 30, The ratio of the light emitted from the light emitting surface 30a is increased.

  As a result, the light utilization efficiency is increased, and even when the light emitting diode 21 is caused to emit light with low power consumption, the desired luminance can be sufficiently ensured, so that the cost can be reduced. Moreover, it is possible to reduce luminance unevenness and color unevenness even though the backlight device 140 is thin.

<Driving system of color liquid crystal display device 100>
The transmissive color liquid crystal display device 100 having such a configuration is driven by a drive circuit 200 as shown in FIG. 8, for example. The driving circuit 200 includes a color liquid crystal display panel 110, a power supply unit 210 that supplies driving power for the backlight device 140, an X driver circuit 220 and a Y driver circuit 230 that drive the color liquid crystal display panel 110, and an image supplied from the outside. RGB process processing unit 250 to which a signal and a video signal received by a receiving unit (not shown) included in transmission type color liquid crystal display device 100 and processed by a video signal processing unit are supplied via input terminal 240, An image memory 260 and a control unit 270 connected to the RGB process processing unit 250, a backlight drive control unit 280 for driving and controlling the backlight device 140, and the like are provided.

  In the drive circuit 200, the video signal input through the input terminal 240 is subjected to signal processing such as chroma processing by the RGB process processing unit 250, and is further suitable for driving the color liquid crystal display panel 110 from the composite signal. It is converted into an RGB separate signal and supplied to the control unit 270 and also supplied to the X driver 220 via the image memory 260.

  Further, the control unit 270 controls the X driver circuit 220 and the Y driver circuit 230 at a predetermined timing according to the RGB separate signal, and the RGB separate supplied to the X driver circuit 220 via the image memory 260. By driving the color liquid crystal display panel 110 with a signal, an image corresponding to the RGB separate signal is displayed.

The backlight drive control unit 280 generates a pulse width modulation (PWM) signal from the voltage supplied from the power supply 210 and drives each light emitting diode 21 included in the optical unit 21 _mn that is a light source of the backlight device 140. In general, the color temperature of a light emitting diode has a characteristic that it depends on an operating current. Therefore, in order to reproduce the color faithfully (with a constant color temperature) while obtaining a desired luminance, it is necessary to drive the light emitting diode 21 using a pulse width modulation signal to suppress the color change.

  The user interface 300 selects a channel to be received by a receiving unit (not shown) described above, adjusts an audio output amount to be output by an audio output unit (not shown), or from a backlight device 140 that illuminates the color liquid crystal display panel 110. This is an interface for executing white light brightness adjustment, white balance adjustment, and the like.

  For example, when the user adjusts the brightness from the user interface 300, the brightness control signal is transmitted to the backlight drive control unit 280 via the control unit 270 of the drive circuit 200.

  As described above, the backlight device 140 is provided with an optical member such as the light guide plate 30 for the emission angle distribution of the red light, the green light, and the blue light emitted from the red light emitting diode 21R, the green light emitting diode 21G, and the blue light emitting diode 21B. Thus, the liquid crystal display panel 110 is uniformly diffused over the entire surface before entering the diffusion plate 141. And the light radiate | emitted out of the light guide plate 30 is increased by the diffuse reflection area | region 41DR formed in the light guide plate 30 via reflection sheet 40A, 40B directly.

  Therefore, when the liquid crystal display panel 110 is illuminated with illumination light emitted from the backlight device 140, the liquid crystal display panel 110 displays a very bright image with good color reproducibility even with low power consumption. be able to. Further, since the backlight device 140 does not require a space necessary for color mixing with white light, the backlight device 140 can be made thinner than a conventional direct type backlight device. That is, a thin color liquid crystal display device with high color reproducibility can be realized.

It is a disassembled perspective view which shows typically the principal part structure of the color liquid crystal display device to which this invention is applied. It is a figure which shows the structure of the color filter provided in the liquid crystal display panel with which the same color liquid crystal display device was equipped. It is a typical perspective view which shows schematic structure of the backlight apparatus for liquid crystal displays with which the same color liquid crystal display device was equipped. It is a longitudinal cross-sectional view at the time of cut | disconnecting a color liquid crystal display device by the XX line shown in FIG. It is the figure which showed typically the optical path within the light guide plate of the light radiate | emitted from one light emitting diode. It is the figure which showed typically the optical path within the light guide plate of the light radiate | emitted from one light emitting diode at the time of providing a diffuse reflection area | region in a reflection sheet. It is the figure which showed an example of the reflection sheet provided with a diffuse reflection area | region. It is a block diagram which shows the structure of the drive circuit which drives the said color liquid crystal display device.

Explanation of symbols

21R red (R) light emitting diode, 21G green (G) light emitting diode, 21B blue (B) light emitting diode, 21 _n (n is a natural number) light emitting diode unit, 30 light guide plate, 30a bottom surface, 30b side surface, 30z light emitting surface, 31 recess, 31A light incident surface, 40A, 40B reflection sheet, 41DR diffuse reflection area, 41R regular reflection area, 140 liquid crystal display backlight device,

Claims (14)

In a backlight device that illuminates a transmissive liquid crystal display panel with white light from the back side,
A light source composed of a plurality of light emitting diodes each emitting at least red light, green light, and blue light;
An optical member that covers the light emission direction of the plurality of light emitting diodes as the light source, and controls the emission angle distribution of the colored light emitted from each of the light emitting diodes;
Diffuse reflection means for diffusing and reflecting the colored light that enters the optical member and is guided while repeating total reflection;
A backlight device, comprising: a diffusion plate that diffuses the color light emitted from the optical member to emit planar light. 2. The backlight device according to claim 1, wherein the optical member is a light guide plate in which a plurality of recesses for storing the light emitting surfaces of the plurality of light emitting diodes that are the light sources are formed. The diffuse reflection means is formed on a reflection sheet that is affixed to a surface other than the light exit surface of the light guide plate and that regularly reflects the colored light guided through the light guide plate. The backlight device according to 1. The backlight device according to claim 3, wherein the reflection sheet on which the diffuse reflection means is formed is attached to a surface of the light guide plate that faces the light emitting surface. The backlight device according to claim 3, wherein the reflection sheet on which the diffuse reflection means is formed is attached to a side surface of the light guide plate. The backlight device according to claim 1, wherein the diffuse reflection means is directly printed on the light guide plate. The backlight device according to claim 1, wherein the light emitting diode is a side emission light emitting diode provided with an optical component that emits light emitted from a light source from a side surface. In a liquid crystal display device comprising a transmissive liquid crystal display panel and a backlight device that illuminates the liquid crystal display panel with white light from the back side,
The backlight device includes a light source including a plurality of light emitting diodes that emit at least red light, green light, and blue light, respectively.
An optical member that covers the light emission direction of the plurality of light emitting diodes as the light source, and controls the emission angle distribution of the colored light emitted from each of the light emitting diodes;
Diffuse reflection means for diffusing and reflecting the colored light that enters the optical member and is guided while repeating total reflection;
A liquid crystal display device comprising: a diffusion plate that diffuses the color light emitted from the optical member to emit planar light. 9. The liquid crystal display device according to claim 8, wherein the optical member is a light guide plate in which a plurality of recesses for storing the light emitting surfaces of a plurality of light emitting diodes that are the light sources are formed. The diffuse reflection means is formed on a reflection sheet that is affixed to a surface other than the light exit surface of the light guide plate and that regularly reflects the colored light guided through the light guide plate. 9. A liquid crystal display device according to 8. The liquid crystal display device according to claim 10, wherein the reflection sheet on which the diffuse reflection means is formed is attached to a surface of the light guide plate that faces the light emitting surface. The liquid crystal display device according to claim 10, wherein the reflection sheet on which the diffuse reflection means is formed is attached to a side surface of the light guide plate. The liquid crystal display device according to claim 8, wherein the diffuse reflection means is directly printed on the light guide plate. The liquid crystal display device according to claim 8, wherein the light emitting diode is a side emission light emitting diode provided with an optical component that emits light emitted from a light source from the side surface.

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