JP2010055771A - Light guide and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light guide with high luminance on an irradiating face and capable of area control. <P>SOLUTION: The light guide 104 is constituted of four light guide units 102a to 102d arranged adjacently with one another. Each light guide unit has an irradiating face, two incident faces, and two opposed reflecting faces opposed to each incident face. The reflecting faces are opposed to the irradiating face and are slanted from an interface of the two incident faces toward an interface of the two opposed faces via a face parallel with the irradiating face. Each light guide unit is optically separated from other with reflecting sheets 151a, 151b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an edge light type backlight used for a non-self-luminous display, and further relates to an edge light type backlight suitable for area control.

  Since a liquid crystal display, which is a typical non-self-luminous display, does not emit light, the liquid crystal itself needs some light source to display characters and images. There are two types of liquid crystal displays: projection type and direct view type. For direct-view liquid crystal displays, depending on how the light source is used, transmissive liquid crystal displays that use backlights, reflective liquid crystal displays that use natural light and room light, and transflective liquid crystals that have transmissive and reflective functions A display is present. Liquid crystal televisions and personal computers employ transmissive liquid crystal displays that can display high-luminance screens.

  The backlight of the transmissive liquid crystal display includes an edge light type backlight and a direct type backlight depending on the position of the light source with respect to the liquid crystal panel. In an edge-light type backlight, light radiated from one or more light sources arranged on the side of the liquid crystal panel is caused to travel while being totally reflected by a light guide plate arranged on the back surface of the liquid crystal panel, and the scattered light is liquid crystal panel Use as direction surface light source. In the direct type backlight system, a plurality of light emitting sources are arranged on the back side of the liquid crystal panel so as to form a surface light source, and directly illuminate the liquid crystal panel.

  Edge light type backlights are often used in thin liquid crystal televisions and notebook computers because a light source can be disposed on the side of a liquid crystal panel. However, the edge light type backlight has a problem of increasing the luminance because the light source is disposed only around the light guide plate. In Patent Document 1, two adjacent side surfaces are incident surfaces, the front surface is an output surface, and the back surface is gradually thinned from each incident surface side toward each opposing side. A light guide plate configured to have two inclined surfaces inclined in such a manner and the two inclined surfaces intersect diagonally is disclosed (FIG. 2).

In addition, this document is a flat rectangular shape with the four side surfaces as the entrance surface, the front surface as the exit surface, and the back surface gradually decreasing in thickness from the entrance surface side toward the center point between them. A light guide plate having four inclined surfaces 15 is disclosed (FIG. 6). Patent Document 2 is formed of a plate-shaped transparent resin molded body having a front surface, a back surface, and four side surfaces, the surface is a light emitting surface, and at least two opposing surfaces of the four side surfaces are light incident surfaces. A light guide plate is disclosed in which the back surface is a light reflecting surface composed of a surface formed such that the plate thickness decreases from the light incident surface toward the center. Patent Document 3 discloses a technique in which a light guide plate is divided into blocks, LEDs are arranged therebetween, and the LEDs are driven for each block.
JP 2001-167622 A International Publication No. 2004/081444 Pamphlet JP 2007-293339 A

  Since both of the light guide plates described in Patent Document 1 and Patent Document 2 are provided with two or more incident surfaces, the luminance can be made higher than that of the light guide plate having one incident surface. However, the light guide plates described in these documents are not used for area control. Moreover, the backlight described in Patent Document 3 is one in which LEDs are arranged between the divided light guide plates, and the LEDs are arranged immediately below the liquid crystal panel. Since the luminance of the surface of the light guide plate is uniform in the sidelight type backlight, the area control in the non-self light emitting type display is performed exclusively by the direct type backlight.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a light guide having a high emission surface brightness and capable of area control. A further object of the present invention is to provide a light guide that is easy to manufacture. A further object of the present invention is to provide a backlight, a liquid crystal display device and a television receiver using these light guides.

  The light guide according to the first aspect of the present invention is composed of four light guide units. Each light guide unit has an emission surface, two incident surfaces arranged adjacent to each other at a predetermined angle, two opposed surfaces arranged to face each incident surface, and opposed to the emission surface. And a reflecting surface that is inclined from the vicinity of the boundary between the two incident surfaces to the boundary between the two opposing surfaces via a surface parallel to the emission surface. The predetermined angle can be approximately a right angle. Since the light guide includes a reflective surface including a plane parallel to the exit surface in the vicinity of the boundary between the two entrance surfaces, the area of the entrance surface is maximized within the range in which the thickness of the light guide is allowed. Efficiency can be improved and the brightness | luminance of an output surface can be made high. In addition, since each of the light guide units is optically separated from each other, area control can be performed in units of the light guide units.

  By providing a reflective material on each of the two opposing surfaces, the light guide unit can be optically separated and light can be used effectively as a surface light source. The reflecting surface can be formed by two flat surfaces, a surface that is substantially flat and parallel to the emitting surface, and a surface that is inclined with respect to the emitting surface. In this case, since the shape is simple, manufacture is easy. Further, the reflecting surface can be formed by three planes each composed of one surface substantially flat and parallel to the emitting surface and two surfaces inclined with respect to the emitting surface.

  By equally dividing the light exit surface of the light guide, the shape of the light exit surface of each light guide unit can be made the same. In this case, the light guide units arranged at diagonal positions to form the light guide have the same shape and are easy to manufacture. The shape of the exit surface can be rectangular or square. If a backlight is configured by arranging a plurality of independent light sources at positions facing each incident surface of each light guide unit with respect to the light guide according to the present invention, brightness adjustment is performed in units of light sources. Can do. A fluorescent lamp or LED can be adopted as the light source. If an LED is used, power can be saved by performing detailed power control.

  In the second aspect of the present invention, the four light guide units shown in the first aspect are arranged at each of the four corners of the light guide, and two light guide units of other shapes are arranged therebetween. To do. Each of the two light guide units includes an exit surface, an entrance surface, a facing surface disposed to face the entrance surface, and a surface that faces the exit surface and is inclined from the entrance surface toward the facing surface. And a reflective surface including The reflection surface may be composed only of a tilted surface, or may be composed of a surface parallel to the tilted surface and the exit surface. Each of the six light guide units is optically separated from each other. With this configuration, the light guide can be divided into six areas for area control.

  According to the present invention, it is possible to provide a light guide having a high emission surface brightness and capable of area control. Furthermore, according to the present invention, an easily manufactured light guide can be provided. Furthermore, according to the present invention, a backlight, a liquid crystal display device, and a television receiver using these light guides can be provided.

  FIG. 1 is a side view and a plan view showing a schematic structure of a liquid crystal display device and a backlight. The liquid crystal display device 10 is mainly composed of an array cell substrate 11 and a sidelight type backlight (hereinafter simply referred to as a backlight) 100. FIG. 1A is a side view of the liquid crystal display device 10, and FIG. 1B is a plan view of the backlight 100. FIG. 1A corresponds to a side view seen from the position of the arrow AA in FIG. Note that the sidelight type backlight is also referred to as an edge light type backlight or a light guide plate type backlight. The array cell substrate 11 has a structure in which a liquid crystal material is sandwiched and held between an array substrate compatible with an active matrix system and a color filter substrate. On the array substrate, thin film transistors (TFTs) are formed in a matrix, and a pixel region is formed together with a pixel capacitor composed of liquid crystal.

  The backlight 100 includes a light guide plate 101, a light source, and lamp reflectors 109a to 109d. The light guide plate 101 includes a light guide 104, an optical sheet 103, and a reflection sheet 105. Although only the fluorescent lamps 107c2 and 107d2 are shown in FIG. 1A, the light sources are housed in the lamp reflectors 109a to 109d at positions corresponding to the incident surfaces of the light guide units 102a to 102d. Has been. In this embodiment, a linear fluorescent lamp such as a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (HCFL), and an external electrode fluorescent tube (EEFL) is used as the light source. A fluorescent lamp or a light emitting diode (LED) may be used.

  The light guide 104 is composed of four divided light guide units 102a to 102d. An optical sheet 103 is attached to the light guide 104 on the array cell substrate 11 side, and a reflective sheet 105 is attached to the opposite side of the array cell substrate 11. In FIG. 1B, the optical sheet 103 is omitted. In the backlight 100 having such a configuration, the light emitted from each fluorescent lamp and the light reflected by the lamp reflectors 109a to 109d enter the respective light guide units 102a to 102d, and the light guide units 102a to 102d pass through the interior of the light guide unit. The light travels while being totally reflected, and the light exceeding the critical angle enters the array cell substrate 11 through the optical sheet 103.

  In the present specification, the surface on which the optical sheet 103 of the light guide 104 and each of the light guide units 102a to 102d is stretched is referred to as an emission surface, and the surface on which the reflection sheet 105 is stretched is referred to as a reflection surface. Further, in each of the light guide units 102a to 102d, a surface facing the fluorescent lamp is referred to as an incident surface, and a surface facing the incident surface is referred to as an opposing surface.

  FIG. 2 is a perspective view showing the outer shape of the light guide unit 102d that constitutes a part of the light guide 104. FIG. 3 shows the light guide 104 formed by combining four light guide units 102a to 102d. It is a perspective view which shows an external shape. 2A and 3A are diagrams with the reflection surface facing up, and FIGS. 2B and 3B are diagrams with the emission surface facing up. The light guide units 102a to 102d are formed by injection molding or cutting using a transparent synthetic resin material such as polymethyl methacrylate resin (PMMA) or polycarbonate (PC). The transmittance of the light guide material is preferably 90% or more. In this embodiment, since the rectangular light guide 104 is configured to be equally divided into four parts, the light guide units 102a and 102c have a rectangular emission surface and the same internal structure. 102b and 102d also have a rectangular exit surface and the same internal structure.

  However, this invention is not limited to the light guide 104 which combined the light guide unit equally divided into four. The division position can be determined in accordance with the area control request described later. For example, when a belt-like character area is displayed on the lower side of the screen, an elongated light guide unit may be included accordingly. Moreover, when the light emission surface of the light guide 104 is a square, it can be divided | segmented equally and the light emission surface of each light guide unit 102a-102d can be made into a square. Since the structure of the light guide units 102a to 102d can be understood by describing one of the light guide units as a representative, the light guide unit 102d will be described below.

  The light guide unit 102d has a seven-surface structure that includes a flat surface that is partially removed from the shape of the plate-shaped rectangular parallelepiped. In addition, in this specification, the case where the surface is provided with minute unevenness formed on the surface of the light guide unit for optical processing is included. The incident surface 121d2 configured by the vertices P1, P2, P6, and P5 and the incident surface 121d1 configured by the vertices P2, P3, P7, and P6 are both rectangular and connected at right angles. The height dimension of the incident surface 121d1 and the incident surface 121d2 defines the thickness of the light guide 104.

  The facing surface 123d2 formed by the vertices P7, P8, P4, and P3 and the facing surface 123d1 formed by the vertices P5, P8, P4, and P1 are both trapezoidal and face the incident surfaces 121d2 and 121d1, respectively, and are perpendicular to each other. To contact. The reflection surface 127d formed by the vertices P5, P6, and P7 is parallel to the emission surface 131d formed by the vertices P1, P2, P3, and P4. The length of the side connecting vertices P8 and P4 that define the boundary between the opposing surfaces 123d1 and 123d2 is shorter than the length of the side connecting the vertices P2 and P6 that define the boundary between the incident surfaces 121d2 and 121d2. The reflecting surface 129d formed by the vertices P5, P7, and P8 is inclined from the side connecting the vertices P5 and P7 toward the vertex P8.

  In other words, the light guide unit 102d has a reflecting surface composed of the reflecting surfaces 127d and 129d, and passes through the reflecting surface 127d parallel to the exit surface 131d from the vicinity of the boundary between the incident surfaces 121d1 and 121d2. It can be said that the thickness of 129d and the emission surface 131d is gradually reduced toward the boundary where the opposing surfaces 123d1 and 123d2 are adjacent to each other. Since the light guide unit 102d has two incident surfaces 121d1 and 121d2 adjacent at right angles, it can obtain a larger amount of incident light than a light guide having only one incident surface. Further, since the shape of the two adjacent incident surfaces 121d1 and 121d2 is not trapezoidal or triangular, but rectangular, the area where the light from the fluorescent lamp enters is maximized within the allowable thickness range of the light guide 104. Efficiency is good. The length of the sides of the apexes P8 and P4 adjacent to the opposing surfaces 123d1 and 123d2 is not particularly limited, but can be about 0.1 mm or less. When set to zero, the shapes of the facing surfaces 123d1 and 123d2 are triangular.

  The four light guide units 102a to 102d are arranged and assembled as shown in FIG. 3 in order to form the light guide 104 having a rectangular emission surface. The assembling method can be performed by using an adhesive or fixing to an frame. It is desirable to arrange the light guide units as close to each other as possible so as not to cause uneven brightness on the exit surface of the light guide 104. The light guide units 102 a to 102 d are arranged such that opposing surfaces having the same length face each other, and an incident surface faces each side outside the light guide 104. As will be described later, a plurality of fluorescent lamps are arranged at positions facing the respective incident surfaces. And each light guide unit 102a-102d is optically isolate | separated by the reflective sheets 151a-151d provided between the opposing surfaces. The reflective sheets 151a to 151d transmit the light incident on the opposing surface in the direction of the light guide so that the light inside each light guide unit 102a to 102d does not pass through the opposing surface and enter the adjacent light guide unit. To reflect.

  The material of the reflective sheet is not particularly limited, but can be a white or mirror film or sheet. Instead of the reflective sheet, white ink may be directly silk screen printed on the opposite surface. Moreover, although it may be a black light-shielding sheet for optical separation, the reflecting sheet is desirable because the incident light can be effectively used as a surface light source in each of the light guide units 102a to 102d.

  In the light guide unit 102d, light incident from the two incident surfaces 121d1 and 121d2 travels by being reflected or totally reflected by the reflecting surfaces 127d and 129d, the opposing surfaces 123d1 and 123d2, and the emitting surface 131d. The light further scattered and incident on the exit surface 131 d at a critical angle or less passes through the exit surface 131 d and enters the array cell substrate 11 through the optical sheet 103. Light incident at a critical angle or greater is totally reflected at the exit surface 131d and is repeatedly reflected inside the light guide unit 102d. Light that has been repeatedly reflected inside the light guide 102d increases in attenuation as the distance from the incident surfaces 121d1 and 121d2 increases. However, between the reflecting surface 129d that forms a wedge shape and the exit surface 131d, the incident surface Since the reflection is repeated so that the critical angle becomes smaller as the distance from the distance increases, the optical path length to the emission gradually becomes shorter, and the luminance of the emission surface is made uniform.

  It is to be noted that an uneven pattern is formed on the surfaces of the reflecting surfaces 127d and 129d, or a material containing minute beads that scatter light is silk-screen printed in a predetermined pattern to further increase the luminance of the exit surface 131d. It may be made uniform. The fine concavo-convex pattern may be, for example, a plurality of V-shaped grooves, a cylindrical or hemispherical protrusion. Instead of forming a reflection pattern on the reflection surfaces 127d and 129d, a reflection sheet having such a function may be prepared and provided near the reflection surfaces 127d and 129d.

  Although FIG. 2 shows an example in which the reflecting surface is composed of two surfaces, the present invention can also be composed of three or more reflecting surfaces. FIG. 4 is a perspective view in which a light guide unit having three reflecting surfaces is arranged with the reflecting surface facing upward. The reflecting surface 161 is parallel to the exit surface located on the lower surface in the figure, and the side that demarcates the opposing surfaces 167 and 169 is shorter than the side that demarcates the incident surfaces 173 and 175. The reflective surfaces 163 and 165 are inclined so that the thickness of the light guide gradually decreases toward the opposing surfaces 167 and 169, respectively. In the light guide shown in FIG. 4 as well, the incident surfaces 173 and 175 have a rectangular shape, so that the area of the incident surface is maximized within a predetermined thickness range of the light guide plate, and the inclined surfaces 163 and 165 are based on the wedge-shaped principle. Thus, the luminance of the exit surface can be made uniform.

  In this embodiment, the light guide is composed of a plurality of light guide units. When the light guide whose output surface is rectangular is equally divided into four, the shapes of the two light guide units are the same. In any case of molding and cutting, it is more cost effective to assemble and form the light guide with a small light guide unit than to integrally form the large size. In addition, when the light guide unit is formed by cutting instead of molding by a mold, the shape of FIG. 2 with a small number of reflecting surfaces is easier to manufacture.

  Next, a method for performing area control using the backlight 100 in the liquid crystal display device will be described. Area control is to logically divide the LCD panel into multiple display areas and control the brightness for each divided area to increase the contrast of the screen and reduce the power of the backlight. Say. The area control is performed by controlling the light emission luminance for each pixel in the self-luminous display, and controlling the luminance of the backlight for each display region in the non-self light emitting display.

  Next, a method for performing area control using the backlight 100 according to the present embodiment will be described. FIG. 5A is a block diagram illustrating a configuration of the liquid crystal display device 10, and FIG. 5B is a block diagram illustrating a configuration of the backlight control circuit 21. The liquid crystal display device 10 includes an array cell substrate 11, a backlight 100, a liquid crystal panel control circuit 19, and a backlight control circuit 21. The liquid crystal panel control circuit 19 receives red, green, and blue image data RGB for displaying an image on the liquid crystal panel 13 from a television receiver serving as a host device or a graphic memory (not shown) of a computer system. The synchronization signal SYNC is received, serial image data is created on the time axis, and supplied to the data line driving circuit 15 and the scanning line driving circuit 17. Further, the liquid crystal panel control circuit 19 receives a power supply DC from the host device or the outside.

  The array cell substrate 11 includes a liquid crystal panel 13, a data line driving IC 15, and a scanning line driving IC 17. The data line driving IC 15 applies a signal voltage corresponding to the image data to the drain of the TFT, and the scanning line driving IC 17 applies a line sequential scanning signal to the gate of the TFT, thereby generating serial image data for each frame period. A planar image is displayed on the liquid crystal panel 13 by sequentially writing the pixel capacity.

  In FIG. 5A, the optical sheet 103 and the lamp reflectors 109a to 109d are omitted from the backlight 100. Eight linear fluorescent lamps 107a1 to 107d2 are arranged at positions facing the two incident surfaces of the light guide units 102a to 102d. The backlight control circuit 21 performs area control of the liquid crystal panel 13 by controlling the light emission amounts of the fluorescent lamps 107a1 to 107d2. The liquid crystal panel 13 is logically divided into four display areas corresponding to the light guide units 102a to 102d. Hereinafter, each logically separated display area is referred to as a control area.

  The luminance analysis unit 31 refers to the address information storage unit 33 and calculates the average luminance for each control region from the red, green, and blue image data RGB received from the liquid crystal panel control circuit 19. The address information section 33 stores the address information of the TFT corresponding to each control area and the address information of the fluorescent lamps 107a1 to 107d2. The control unit 35 generates light emission information for determining the light emission amounts of the fluorescent lamps 107a1 to 107d2 based on the average luminance generated by the luminance analysis unit 31 and the address information stored in the address information storage unit 33, and performs dimming. Send to part 37.

  The control unit 35 calculates the light emission information so that the light emission amount of the light source is a small value when the average luminance of each control region is small, and the light emission amount is a large value when the average luminance is large. The light control unit 37 includes a light control circuit including an inverter, and controls the light emission amount of each of the fluorescent lamps 107a1 to 107d2 based on the light emission information. In the backlight 100, since the opposing surfaces of the light guide units 102a to 102d are shielded from each other, the light traveling through one light guide unit travels inside the other light guide unit and is emitted from the light exit surface. Area control can be performed reliably without affecting the brightness.

  The backlight control circuit 21 can reduce the power of the fluorescent lamp, for example, by turning off one of the two fluorescent lamps 107a1 and 107a2 for the light guide unit 102a based on the image signal RGB. If an LED instead of a fluorescent lamp is used as the light source, detailed power control can be performed simultaneously with dimming by controlling the LED drive current, which is more effective in reducing power.

  The liquid crystal display device 100 can be used in a television receiver by receiving RGB image signals as television video signals. In this case, the area control can also be used when displaying a different screen such as when displaying a multi-screen display of a TV image or displaying a computer screen on a part of the TV image.

  FIG. 6 is a diagram illustrating another example of the backlight according to the present embodiment. 6A is a plan view of the backlight 200 with the emission surface of the light guide 210 facing up, and FIG. 6B is a perspective view with the reflection surface of the light guide 210 facing up. In FIG. 6B, the exit surface is located on the lower surface. In FIG. 6 (A), the lamp reflector and the optical sheet are excluded. The light guide 210 is formed of six light guide units 201 to 211 arranged so that the shape of the emission surface is rectangular and the emission surface is equally divided into six. The structures of the light guide units 201, 205, 207, 211 arranged at the four corners of the light guide 210 are the same as those of the light guide units 102a, 102b, 102c, 102d shown in FIG.

  The two light guide units 203 and 209 arranged other than the corners have the same structure. The light guide unit 203 includes a rectangular incident surface 203a and a reflective surface 203b. The height of the incident surface 203a (dimension in the thickness direction of the light guide) is equal to the height of the incident surfaces of the light guide units 201 and 205. The reflecting surface 203b is inclined so that the thickness of the light guide gradually decreases from the position communicating with the incident surface 203a toward the center. In this example, the reflecting surface is configured as a single surface, but may be configured so as to include a surface parallel to the emitting surface as in other light guide units.

  A reflective sheet 151 is provided between the opposing surfaces of each light guide unit, and each light guide unit is optically separated. Ten fluorescent lamps 201a to 211b are arranged at positions facing the incident surface of each light guide unit, and area control is possible in units of fluorescent lamps. FIG. 7 shows an example in which four L-shaped fluorescent lamps 301a to 301d are arranged in place of the eight linear fluorescent lamps 107a1 to 107d2 in the liquid crystal display device shown in FIG. The fluorescent lamps 301a to 301d are arranged at positions facing the two incident surfaces of the light guide units 102a to 102d, respectively. In this case, the backlight control circuit 21 can perform area control in units of the fluorescent lamps 301a to 301d.

  Although the present invention has been described with the specific embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and is known so far as long as the effects of the present invention are achieved. It goes without saying that any configuration can be adopted.

It is the side view and top view explaining the schematic structure of a liquid crystal display device and a backlight. It is a perspective view of a light guide unit. It is a perspective view which shows the external shape of a light guide. It is a perspective view which shows the other example of a light guide unit. It is a block diagram which shows the structure of a liquid crystal display device. It is a figure which shows the other example of a backlight. It is a figure which shows an example when using an L-shaped fluorescent lamp.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display device 11 ... Array cell board | substrate 100, 200 ... Side light type backlight 101 ... Light guide plate 102a-102d ... Light guide body unit 104, 210 ... Light guide body 107a1-107d2 ... Fluorescent lamp 121d1, 121d2 ... Incident Surface 123d1, 123d2 ... Opposing surface 131d ... Outgoing surface

Claims (15)

A light guide for backlight composed of four light guide units arranged adjacent to each other,
Each light guide unit is
An exit surface;
Two incident surfaces adjacent at a predetermined angle;
Two opposing surfaces facing each entrance surface;
A reflective surface that is opposed to the emission surface and is inclined from a vicinity of a boundary between the two incidence surfaces to a boundary between the two opposed surfaces via a plane parallel to the emission surface;
A light guide in which each of the light guide units is optically separated from each other.   The light guide according to claim 1, wherein a reflective material is provided on the two opposing surfaces of each light guide unit.   The light guide according to claim 1, wherein the reflecting surface is formed of two substantially flat surfaces.   The light guide according to claim 1, wherein the reflecting surface is formed by three substantially flat surfaces.   The light guide according to any one of claims 1 to 4, wherein each light guide unit has the same exit surface.   The light guide according to claim 5, wherein a shape of the emission surface is a rectangle.   The light guide according to claim 5, wherein a shape of the emission surface is a square. A light guide according to any one of claims 1 to 7,
A backlight having a plurality of light sources arranged independently of each incident surface of each light guide unit.   The backlight according to claim 8, wherein the light source is a fluorescent lamp.   The backlight according to claim 8, wherein the light source is an LED. An array cell substrate;
A liquid crystal panel control circuit for controlling the operation of the thin film transistor provided on the array cell substrate based on an image signal;
A backlight for illuminating the array cell substrate;
A backlight control circuit for individually controlling the luminance of the light source of the backlight based on an image signal,
A liquid crystal display device, wherein the backlight is the backlight according to any one of claims 8 to 10. A light guide for backlight composed of six light guide units arranged adjacent to each other,
Each of the four light guide units arranged at each corner of the light guide,
An exit surface;
Two incident surfaces adjacent at a predetermined angle;
Two opposing surfaces facing each entrance surface;
A reflective surface that is opposed to the output surface and is inclined from the vicinity of the boundary between the two incident surfaces toward the boundary between the two opposed surfaces via a surface parallel to the output surface;
Each of the other two light guide units
An exit surface;
An incident surface;
A facing surface facing the incident surface;
A reflecting surface that includes a surface that faces the exit surface and is inclined from the incident surface toward the facing surface;
A light guide in which each of the light guide units is optically separated from each other. A light guide according to claim 12;
A backlight having a plurality of light sources arranged independently of each incident surface of each light guide unit. An array cell substrate;
A liquid crystal panel control circuit for controlling the operation of the thin film transistor provided on the array cell substrate based on an image signal;
A backlight for illuminating the array cell substrate;
A backlight control circuit for individually controlling the luminance of the light source of the backlight based on an image signal,
A liquid crystal display device, wherein the backlight is the backlight according to claim 13.   A television receiver comprising the liquid crystal display device according to claim 11 or 14.

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