JP2005338429A - Backlight and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reliably and easily irradiate pixels of respective colors of a liquid crystal panel and the like displaying an image constituted by arrangement of pixels of a plurality of colors e.g. RGB with light of corresponding colors. <P>SOLUTION: A red light emitting diode 51, a green light emitting diode 52, and a blue light emitting diode 53 emit red light, green light, and blue light, respectively. A red light guide 61 has a belt-like flat plane D having a width corresponding to a pixel and guides the red light emitted by the red light emitting diode 51 to the flat surface D to irradiate a red pixel with the red light. Green and blue light guides 62 and 63 are also constituted in the same manner. The red, green and blue light guides 61, 62, and 63 are periodically disposed and disposed so that flat surfaces D to F are arranged on a flat surface parallel to a display surface on which the image is displayed. This invention can be applied to e.g. a color transmission type liquid crystal display. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a backlight and a liquid crystal display device, and in particular, to each color pixel such as a liquid crystal panel that displays an image constituted by an array of pixels of a plurality of colors such as RGB (Red, Green, Blue). The present invention relates to a backlight and a liquid crystal display device that can reliably and easily emit light of a corresponding color.

  2. Description of the Related Art Conventionally, there is a device that uses a white light source as a backlight in a color transmission type liquid crystal display device (LCD (Liquid Crystal Display)).

  FIG. 1 is a cross-sectional view showing a configuration of an example of a liquid crystal display device using this white light source.

  1 includes a white light source 11, a diffusion plate 12, a diffusion film 13, a BEF (Brightness Enhancement Firm) (trademark) 14, a diffusion film 15, a D-BEF 16, and an LCD panel 17. The liquid crystal display device 1 irradiates the LCD panel 17 with white light emitted from the white light source 11 via the diffusion plate 12, the diffusion film 13, the BEF 14, the diffusion film 15, and the D-BEF 16, thereby generating an image. Is displayed. Here, the image displayed by the liquid crystal display device 1 is configured by an array of red pixels (hereinafter referred to as red pixels), green pixels (hereinafter referred to as green pixels), and blue pixels (hereinafter referred to as blue pixels). Is done.

  The white light source 11 is generally composed of a CCFL (Cold Cathode Fluorescent Lamp) (cold cathode tube). In this case, for example, a large number of red light emitting diodes (LEDs), green light emission It consists of a diode and a blue light emitting diode. The white light source 11 is additively mixed with red light emitted by many red light emitting diodes, green light emitted by many green light emitting diodes, and blue light emitted by many blue light emitting diodes. The diffusion plate 12 is irradiated with white light formed by the above.

  The diffusion plate 12 diffuses white light incident from the white light source 11 and irradiates the diffusion film 13. The diffusion film 13 further diffuses the white light incident from the diffusion plate 12 and irradiates the BEF 14.

  The BEF 14 is the viewing angle of the liquid crystal 24 of the LCD panel 17 of the P component of the white light incident from the diffusion film 13 (the angle formed with respect to the direction perpendicular to the LCD panel 17. Light that deviates from the angle at which the transmitted light is visible to the user) is collected, the light traveling direction is restricted in the upward direction in the figure, and is incident on the LCD panel 17 via the diffusion film 15 and the D-BEF 16 To do. That is, since the liquid crystal 24 of the LCD panel 17 has a viewing angle, light that is shifted by a predetermined angle or more from a direction perpendicular to the LCD panel 17 cannot be seen by the user even if it passes through the LCD panel 17. For this reason, the BEF 14 condenses the P component of white light emitted in a direction deviating from the viewing angle in accordance with the viewing angle of the liquid crystal 24 and directs it to the front of the LCD panel 17, thereby producing white light. Is used effectively.

  The D-BEF 16 converts the S component of the white light incident from the BEF 14 through the diffusion film 15 into the P component, and then condenses the light deviating from the viewing angle of the liquid crystal 24 of the LCD panel 17. Thus, the light traveling direction is restricted in the upward direction in the figure, and the LCD panel 17 is irradiated. That is, since the LCD panel 17 is configured to transmit only the P component, the D-BEF 16 deflects the S component to the P component, and then performs the same processing as the BEF 14. Irradiate. Note that the D-BEF 16 irradiates the LCD panel 17 as it is without processing the P component processed by the BEF 14.

  The LCD panel 17 includes a polarizing plate 21, a TFT (Thin Film Transistor) 22, a color filter 23, a liquid crystal (display element) 24, and a polarizing plate 25.

  The polarizing plate 21 transmits light of a predetermined polarization direction out of white light incident from the D-BEF 16 and irradiates the color filter 23 via the TFT 22.

  The TFT 22 is provided for each pixel, and controls the voltage applied to the liquid crystal 24 for each pixel.

  The color filter 23 is configured by, for example, an array of thin film red filters, green filters, and blue filters. That is, in the color filter 23, the red filter, the green filter, and the blue filter are periodically arranged in the order, for example, in the horizontal direction, and are arranged on a straight line in the vertical direction. More specifically, in the color filter 23, a red filter is arranged in the first column (first vertical column from the left), a green filter is arranged in the second column, and the third A blue filter is disposed in the column, a red filter is disposed in the fourth column, and similarly, a red filter, a green filter, and a blue filter are periodically disposed in the horizontal direction.

  One red filter has a size corresponding to one pixel of the liquid crystal 24, and the same applies to the green filter and the blue filter. White light that passes through the polarizing plate 21 and enters the color filter 23 via the TFT 22 passes through the red filter, the green filter, or the blue filter, and becomes red, green, or blue light, respectively. By irradiating the corresponding pixels of the liquid crystal 24, the liquid crystal display device 1 displays a color image. Therefore, the arrangement of the red pixels, the green pixels, and the blue pixels that constitute the image displayed by the liquid crystal display device 1 is equal to the arrangement of the red filters, the green filters, and the blue filters of the color filter 23.

  The liquid crystal 24 is provided with a transparent conductive layer (not shown) at the top in the figure, and the transparent conductive layer is grounded. An electric field is generated by applying a voltage between the TFT 22 and the transparent conductive layer, and the liquid crystal 24 has red, green, or blue light emitted from the color filter 23 in each pixel in accordance with the electric field across the pixel. The polarization direction of the light is changed. For example, when there is no electric field across the pixel in a certain pixel, the liquid crystal 24 emits red, green, or blue light irradiated (incident) from the color filter 23 to the pixel, and the polarization direction of the incident light (incident polarization ( The polarizing plate 25 is irradiated by rotating by 90 degrees so as to be orthogonal to the (incident polarization) direction. On the other hand, when there is an electric field across the pixel in a certain pixel, the liquid crystal 24 can directly apply the red, green, or blue light emitted from the color filter 23 to the pixel without changing the polarization direction. 25 is irradiated.

  The polarizing plate 25 is disposed so as to transmit light having a polarization direction orthogonal to the polarization direction of light transmitted by the polarizing plate 21. Accordingly, the polarizing plate 25 transmits only the light irradiated from the liquid crystal 24 and rotated by the liquid crystal 24 so that the polarization direction is orthogonal to the incident polarization direction, and the polarization direction is not changed. Shut off. Here, as described above, the liquid crystal 24 has red, green, or blue light emitted from the color filter 23 according to the electric field across the pixel, that is, the voltage applied to the liquid crystal 24 by the TFT 22. The light polarization direction is rotated by 90 degrees. Therefore, the TFT 22 can control the light transmitted through the polarizing plate 25 (or blocked by the polarizing plate 25) for each pixel by controlling the voltage applied to the liquid crystal 24 for each pixel. Thereby, the liquid crystal display device 1 can display an arbitrary color.

  In the liquid crystal display device 1 configured as described above, the white light emitted from the white light source 11 passes through the diffusion plate 12, the diffusion film 13, the BEF 14, the diffusion film 15, and the D-BEF 16 to the LCD panel 17. Is irradiated. The polarizing plate 21 of the LCD panel 17 transmits white light having a predetermined polarization direction and irradiates the color filter 23 through the TFT 22. For each pixel, the color filter 23 transmits only light of a color corresponding to the pixel out of white light, and irradiates the polarizing plate 25 via the liquid crystal 24. The polarizing plate 25 transmits or blocks the light depending on the polarization direction of the light irradiated from the color filter 23 via the liquid crystal 24, and a color image is displayed by the light transmitted through the polarizing plate 25. .

  By the way, the red filter, the green filter, or the blue filter of the color filter 23 of the liquid crystal display device 1 described above transmits the red, green, or blue light of the white light. Thus, the red, green, or blue light emitted to the liquid crystal 24 simply has about 1/3 the brightness of the white light emitted from the white light source 11. Accordingly, the brightness of the white light source 11 must be set to a brightness corresponding to about three times the maximum value that can be taken by each pixel constituting the image displayed by the liquid crystal display device 1. The light source 11 must be composed of a large number of light emitting diodes.

  Further, when the white light source 11 is composed of a large number of diodes, the power consumption increases, and it is necessary to take measures against heat generation.

  Therefore, a red light emitting diode, a green light emitting diode, or a blue light emitting diode that emits red, green, or blue light, respectively, is used as a backlight instead of the white light source 11 that emits white light. There has been proposed a liquid crystal display device that eliminates the need for a color filter by irradiating red, green, or blue light emitted from a diode or a blue light emitting diode to pixels of a corresponding color (for example, Patent Document 1). And 2).

  The liquid crystal display device described in Patent Document 1 includes a red light guide in which a red light emitting diode is disposed, a green light guide in which a green light emitting diode is disposed, and a blue light guide in which a blue light emitting diode is disposed. ing. The red light guide is provided with a deformed portion designed to reflect the red light emitted by the red light emitting diode and irradiate the red pixel of the liquid crystal layer. Similarly, the green light guide and the blue light guide are provided with deformation portions.

Furthermore, in the liquid crystal display device described in Patent Document 2, one common light guide is provided instead of the above-described red light guide, green light guide, and blue light guide. The light guide is provided with a deforming portion designed to reflect the light of each color emitted by the light emitting diode of each color and irradiate the corresponding color pixel of the liquid crystal layer. Thereby, the light of a corresponding color can be irradiated to the pixel of each color of a liquid crystal layer, without using a color filter.
JP 2002-196332 A JP 2003-35904 A

  However, the liquid crystal display device configured without providing the color filter described above reflects light of each color by the deforming portion provided in the light guide of each color or the common light guide and irradiates the corresponding pixel. In order to reliably irradiate only the pixels of the corresponding color, the design of the light guide including the deformed portion, the calculation of the arrangement position of the light emitting diode, and the backlight comprising the light emitting diode and the light guide It is expected that the assembly will need to be done fairly precisely.

  The present invention has been made in view of such a situation. For example, a color corresponding to each color pixel such as a liquid crystal panel that displays an image constituted by an array of pixels of a plurality of colors such as RGB is provided. This makes it possible to irradiate light reliably and easily.

  The backlight of the present invention is a first backlight that emits light of a first color in a backlight of a display device that displays an image composed of an array of at least a first color pixel and a second color pixel. A light-emitting diode, a second light-emitting diode that emits light of the second color, and a band-shaped plane having a width corresponding to the pixel, and the first color light emitted by the first light-emitting diode is A first light guide having a flat plate shape that guides to a belt-like plane and irradiates the pixels of the first color, and a second light-emitting diode that has a belt-like plane having a width corresponding to the pixel and emits light from the second light emitting diode. A second light guide having a flat plate shape that guides light of a specific color to the belt-like plane and irradiates the pixels of the second color, and the plurality of first and second light guides are periodic. In addition, the belt-like plane is arranged on a plane parallel to the display surface on which the image is displayed. It is characterized in that is.

  The image is composed of an array of pixels of the first color, pixels of the second color, and pixels of the third color, and the backlight includes a third light emitting diode that emits light of the third color. A flat plate shape having a band-like plane having a width corresponding to the pixel, and irradiating the third color pixel by guiding the third color light emitted by the third light emitting diode to the band-like plane. The third light guide may be further provided, and the plurality of first to third light guides may be periodically arranged so that the belt-like plane is aligned on a plane parallel to the display surface.

  The first color is red, the second color is green, and the third color is blue.

  The backlight includes a fourth light guide that guides light of a first color emitted by one first light emitting diode and a plurality of second light guides with respect to the plurality of first light guides. On the other hand, one third light emitting diode emits light with respect to the fifth light guide that guides the second color light emitted from one second light emitting diode and the plurality of third light guides. A sixth light guide for guiding the third color light may be further provided.

  The first to third light guides are triangular flat plates with the base of the belt-like plane having the thickness of the belt-like plane as the base, and the first to third light emitting diodes are opposed to the base of the triangular flat plate. It can arrange | position with respect to the 1st thru | or 3rd light guide so that light may inject from the vertex side to perform.

  Each of the triangular flat plates serving as the first to third light guides has the first to third light guides in a state where the belt-like plane is arranged on a plane parallel to the display surface. The apex that faces the bottom of one of the third light guides may be formed in a different triangular shape so that it is exposed at a position different from the apex that faces the bottom of the other light guide.

  A plurality of the first to third light guides that are periodically arranged as one unit can be arranged as a unit, and the plurality of units can be arranged so that the belt-like plane is aligned on a plane parallel to the display surface. .

  The liquid crystal display device of the present invention includes a liquid crystal display element and a backlight for illuminating the liquid crystal display element. The backlight includes a first light emitting diode that emits light of a first color, and a second light emitting diode. A second light emitting diode that emits light of a color and a band-shaped plane having a width corresponding to a pixel, and the first color light emitted from the first light-emitting diode is guided to the band-shaped plane. A first light guide having a flat plate shape for irradiating a pixel of the first color, and a band-shaped plane having a width corresponding to the pixel, and the second color light emitted by the second light emitting diode, A second light guide having a flat plate shape that guides to a band-shaped plane and irradiates the pixels of the second color, and the plurality of first and second light guides are periodically and have a band-shaped plane. The liquid crystal display elements on which images are displayed are arranged on a plane parallel to the display surface And it features.

  In the present invention, the first light-emitting diode that emits light of the first color, the second light-emitting diode that emits light of the second color, and a belt-like plane having a width corresponding to the pixel, A first light guide having a flat plate shape that guides the first color light emitted from the first light emitting diode to the band-shaped plane and irradiates the pixel of the first color, and has a width corresponding to the pixel. A flat plate-shaped second light guide that has a belt-like plane, guides the second color light emitted from the second light emitting diode to the belt-like plane, and irradiates the pixels of the second color; The plurality of first and second light guides are periodically arranged so that the belt-like plane is aligned on a plane parallel to the display surface on which the image is displayed.

  According to the present invention, for example, it is possible to reliably and easily irradiate light of a corresponding color to each color pixel such as a liquid crystal panel that displays an image configured by an array of pixels of a plurality of colors such as RGB. .

  Embodiments of the present invention will be described below. Correspondences between constituent elements described in the claims and specific examples in the embodiments of the present invention are exemplified as follows. This description is to confirm that specific examples supporting the invention described in the claims are described in the embodiments of the invention. Therefore, even if there are specific examples that are described in the embodiment of the invention but are not described here as corresponding to the configuration requirements, the specific examples are not included in the configuration. It does not mean that it does not correspond to a requirement. On the contrary, even if a specific example is described here as corresponding to a configuration requirement, this means that the specific example does not correspond to a configuration requirement other than the configuration requirement. not.

  Further, this description does not mean that all the inventions corresponding to the specific examples described in the embodiments of the invention are described in the claims. In other words, this description is an invention corresponding to the specific example described in the embodiment of the invention, and the existence of an invention not described in the claims of this application, that is, in the future, a divisional application will be made. Nor does it deny the existence of an invention added by amendment.

The backlight according to claim 1 (for example, the backlight 41 in FIG. 2),
Of a display device (for example, the liquid crystal display device 40 in FIG. 3) that displays an image constituted by an array of at least a first color pixel (for example, a red pixel) and a second color pixel (for example, a green pixel). In backlight,
A first light emitting diode that emits light of a first color (eg, red light emitting diode 51 of FIG. 2);
A second light emitting diode (eg, green light emitting diode 52 in FIG. 2) that emits light of a second color;
A band-shaped plane having a width corresponding to the pixel (for example, plane D in FIG. 2), and guiding the first color light emitted from the first light emitting diode to the band-shaped plane; A flat plate-shaped first light guide (for example, a red light guide 61 in FIG. 2) that irradiates the pixels of the first color;
A band-shaped plane having a width corresponding to the pixel (for example, plane E in FIG. 2), and guiding the second color light emitted from the second light emitting diode to the band-shaped plane, A flat plate-shaped second light guide (for example, the green light guide 62 in FIG. 2) that irradiates the pixels of the second color,
A plurality of the first and second light guides are periodically arranged so that the belt-like plane is aligned on a plane parallel to a display surface on which the image is displayed. .

The backlight according to claim 2 is:
The image is composed of an array of pixels of the first color (for example, red pixels), pixels of the second color (for example, green pixels), and pixels of the third color (for example, blue pixels). ,
A third light emitting diode that emits light of the third color (for example, the blue light emitting diode 53 of FIG. 2);
A band-shaped plane having a width corresponding to the pixel, and the third color light emitted from the third light emitting diode is guided to the band-shaped plane to irradiate the pixel of the third color. A flat plate-shaped third light guide (for example, the blue light guide 63 of FIG. 2),
The plurality of first to third light guides are periodically arranged so that the belt-like plane is aligned on a plane parallel to the display surface.

The backlight according to claim 4,
The first color emitted by one first light emitting diode (for example, the red light emitting diode 121 in FIG. 7) with respect to a plurality of the first light guides (for example, the red light guide 61 in FIG. 7). A fourth light guide (e.g., red light emitting diode guide 122 in FIG. 7) for guiding the light of
One second light-emitting diode (for example, a green light-emitting diode configured similarly to the red light-emitting diode 121 in FIG. 7) for a plurality of the second light guides (for example, the green light guide 62 in FIG. 3). ) That emits light of the second color that emits light (for example, a green light-emitting diode guide configured similarly to the red light-emitting diode guide 122 of FIG. 7);
One third light-emitting diode (for example, a blue light-emitting diode configured similarly to the red light-emitting diode 121 in FIG. 7) with respect to a plurality of the third light guides (for example, the blue light guide 63 in FIG. 3). And a sixth light guide (for example, a blue light emitting diode guide configured similarly to the red light emitting diode guide 122 of FIG. 7) for guiding the third color light emitted by .

The liquid crystal display device according to claim 8,
In a liquid crystal display device that displays an image composed of an array of at least a first color pixel and a second color pixel,
A liquid crystal display element (for example, the liquid crystal 24 in FIG. 3);
A backlight for illuminating the liquid crystal display element (for example, the backlight 41 in FIG. 3),
The backlight is
A first light emitting diode that emits light of a first color (eg, red light emitting diode 51 of FIG. 3);
A second light emitting diode that emits light of a second color (eg, green light emitting diode 52 of FIG. 3);
A band-shaped plane having a width corresponding to the pixel (for example, plane D in FIG. 2), and guiding the first color light emitted from the first light emitting diode to the band-shaped plane; A flat plate-shaped first light guide (for example, a red light guide 61 in FIG. 2) that irradiates the pixels of the first color;
A band-shaped plane having a width corresponding to the pixel, and guiding the second color light emitted from the second light emitting diode to the band-shaped plane (for example, plane E in FIG. 2); A flat plate-shaped second light guide (for example, the green light guide 62 in FIG. 2) that irradiates the pixels of the second color,
The plurality of first and second light guides are periodically arranged so that the belt-like plane is aligned on a plane parallel to the display surface of the liquid crystal display element on which the image is displayed. It is characterized by that.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

  FIG. 2 is a perspective view showing a configuration example of an embodiment of a liquid crystal display device to which the present invention is applied, and FIG. 3 is a left side view thereof (viewed from direction A in FIG. 2). In the figure, portions corresponding to those in FIG. 1 are denoted by the same reference numerals.

  2 and 3 includes a backlight 41 and an LCD panel 42. The backlight 41 emits light emitted from the red light emitting diode 51, the green light emitting diode 52, and the blue light emitting diode 53. An image is displayed by irradiating the LCD panel 42 through the red light guide 61, the green light guide 62, and the blue light guide 63, respectively. Here, the image displayed by the liquid crystal display device 40 includes an array of red pixels, green pixels, and blue pixels. In FIG. 2, the backlight 41 and the LCD panel 42 are separately illustrated for convenience.

  The backlight 41 includes a red light emitting diode 51, a green light emitting diode 52, a blue light emitting diode 53, a red light guide 61, a green light guide 62, and a blue light guide 63.

  The red light emitting diode 51 emits red light, and the green light emitting diode 52 emits green light. The blue light emitting diode 53 emits blue light.

  The red light guide 61 is made of, for example, a triangular transparent acrylic plate having a strip-like plane D having a width corresponding to the pixel as a thickness and having the bottom side of the plane D side (front side in FIG. 2). The On the apex side of the triangular red light guide 61 facing the bottom side, a red light-emitting diode 51 that makes red light incident into the red light guide 61 is disposed. Here, a reflection film is formed on all portions of the surface of the red light guide 61 except for the red pixel region 101 corresponding to the red pixel on the plane D and the region where the red light emitting diode 51 is disposed. Is provided. As a result, the red light that has entered the red light guide 61 from the red light emitting diode 51 is emitted to the outside from areas other than the red pixel area 101 of the red light guide 61 and the area where the red light emitting diode 51 is disposed. Is to prevent. The red light guide 61 guides the red light emitted from the red light emitting diode 51 to the belt-like plane D, emits it from the red pixel region 101, and irradiates the red pixels of the LCD panel 42. Here, the red light guide 61 has a triangular shape, but may have any shape as long as the surface on which the red light emitting diode 51 is disposed is thin and the surface in contact with the LCD panel 42 is wide.

  The reflective film can be formed by coating the surface of the red light guide 61 with, for example, aluminum.

  In FIG. 2 (the same applies to FIGS. 4 and 5 to be described later), the reflective film is shown only in the region corresponding to the boundary portion between adjacent pixels in the vertical direction (vertical direction). Further, it is also formed at a boundary portion between adjacent pixels in the left-right direction (horizontal direction).

  The green light guide 62 and the blue light guide 63 are configured similarly to the red light guide 61. That is, the green light guide 62 is formed from, for example, a triangular transparent acrylic plate having a strip-shaped plane E having a width corresponding to the pixel as a thickness and having the base on the plane E side (front side in FIG. 2). Composed. On the apex side of the triangular green light guide 62 facing the bottom side, a green light-emitting diode 52 that makes green light incident into the green light guide 62 is disposed. The green light guide 62 guides the green light emitted from the green light emitting diode 52 to the belt-like plane E, emits it from the green pixel region 102, and irradiates the green pixels of the LCD panel 42.

  The blue light guide 63 is formed of, for example, a triangular transparent acrylic plate having a strip-like plane F having a width corresponding to the pixel as a thickness and having the base on the plane F side (front side in FIG. 2). The On the apex side of the triangular blue light guide 63 facing the bottom side, a blue light-emitting diode 53 that makes blue light incident into the blue light guide 63 is disposed. The blue light guide 63 guides the blue light emitted from the blue light emitting diode 53 to the belt-like plane F, emits it from the blue pixel region 103, and irradiates the blue pixels of the LCD panel 42.

  The backlight 41 includes a plurality of red light guides 61, green light guides 62, and blue light guides 63 configured as described above in a band-like plane D to F that periodically emits light to the LCD panel 42. (Thickness of the triangular acrylic plate) is arranged and arranged on a plane parallel to the display surface of the LCD panel 42. That is, in the red light guide 61, the green light guide 62, and the blue light guide 63, the longitudinal directions of the planes D, E, and F are parallel to the column direction (vertical direction) of the display surface in that order, and the planes D and E , F are periodically arranged so as to be included in the same plane.

  Here, as described above, the triangular red light guide 61 is disposed so that the band-like planes D to F for emitting light to the LCD panel 42 are arranged on a plane parallel to the display surface of the LCD panel 42. The vertex of the light guide of one of the green light guide 62 and the blue light guide 63 that faces the base on the belt-like plane (any one of the planes D to F) is on the bottom of the other light guide. It is exposed at a position different from the opposite vertex. This is due to the following reason.

  That is, the red light emitting diode 51 and the green light emitting are respectively provided at the apexes (parts) of the triangular red light guide 61, the green light guide 62, or the blue light guide 63 that face the bases on the belt-like planes D to F side. A diode 52 or a blue light emitting diode 53 is arranged. Accordingly, the vertex of one of the triangular red light guide 61, the green light guide 62, and the blue light guide 63 is exposed at a position different from the vertex of the other light guide. The arrangement of the red light emitting diode 51, the green light emitting diode 52, and the blue light emitting diode 53 and the wiring to the red light emitting diode 51, the green light emitting diode 52, and the blue light emitting diode 53 can be easily performed.

As described above, the red light guide 61, the green light guide 62, and the blue light guide 63 do not have to be in the form of different triangles whose vertices are exposed at different positions. That is, the red light guide 61, the green light guide 62, and the blue light guide 63 may be, for example, the same triangular shape. The red light guide 61, the green light guide 62, or the blue light guide 63 has a thin surface on which the red light emitting diode 51, the green light emitting diode 52, or the blue light emitting diode 53 is disposed and a wide surface in contact with the LCD panel 42. Any shape may be used as long as it is a divergent shape.

  The LCD panel 42 includes a polarizing plate 21, a TFT 22, a liquid crystal (display element) 24, and a polarizing plate 25. The polarizing plate 21, TFT 22, liquid crystal 24, and polarizing plate 25 of FIGS. 2 and 3 are the same as those of FIG.

  The liquid crystal display device 40 includes the backlight 41 so that the planes D to F are in contact with the polarizing plate 21 of the LCD panel 42, and each of the red pixel region 101, the green pixel region 102, and the blue pixel region 103 of the backlight 41. The backlight 41 and the LCD panel 42 are arranged so as to face the red pixel, the green pixel, and the blue pixel of the LCD panel 42, respectively.

  In the liquid crystal display device 40 configured as described above, the red light emitted from the red light emitting diode 51 enters the red light guide 61, is guided by the red light guide 61, and exits from the red pixel region 101. . The red light emitted from the red pixel area 101 is applied to the red pixels of the LCD panel 42. Similar to the red light, the green light emitted by the green light emitting diode 52 is guided to the green pixel of the LCD panel 42 by the green light guide 62 and irradiated, and the blue light emitted by the blue light emitting diode 53 is emitted. Is guided to the blue pixels of the LCD panel 42 by the blue light guide 63 and irradiated. In the LCD panel 42, as described with reference to FIG. 1, transmission or blocking of light is controlled for each pixel, whereby a color image is displayed on a display surface which is a plane on the polarizing plate 25 side.

  FIG. 4 shows a perspective view of the backlight 41 when the backlight 41 is composed of three red light guides 61, three green light guides 62, and three blue light guides 63.

Here, the three red light guides 61 are red light guides 61 _{1 to} 61 ₃ , the three green light guides 62 are green light guides 62 _{1 to} 62 _3, and the three blue light guides 63 are blue light guides. 63 _{1 to} 63 ₃ , respectively. In practice, the red light guides 61 _{1 to} 61 ₃ , the green light guides 62 _{1 to} 62 ₃ , and the blue light guides 63 _{1 to} 63 ₃ are the red light guide 61 and the green light guide 62 from the front side in the figure. , it is disposed so as to line up periodically in the order of blue light guide 63, in FIG. 4, for convenience of explanation, the green light guide 62 ₁ to 62 _3, the direction indicated by arrow X in the drawing, the red light guide 611 _through 61 ₃ are shown shifted by predetermined length with respect to, blue light guide 63 ₁ to 63 _3, the green guide 62 ₁ to 62 ₃ are illustrated further predetermined shifted length fraction relative Yes.

The red light guide 61 ₁ is formed of a triangular acrylic flat plate having a thickness in a band-like plane 71 ₁ (plane D in FIG. 2) having a width corresponding to a pixel and having a base on the side of the plane 71 ₁ . On the plane 71 ₁ , areas (portions) having a size corresponding to the red pixel at positions corresponding to the red pixel of the LCD panel 42 are red pixel areas 101 ₁₁ , 101 ₂₁ , and 101 ₃₁ .

In the plane 71 ₁ , the red pixel regions 101 ₁₁ , 101 ₂₁ , and 101 ₃₁ are regions that remain without forming a reflective film.

Also, here, since red light is irradiated only to the red pixels of the LCD panel 42, the red pixels of the LCD panel 42 are arranged so that the red light is not irradiated to the boundary between the red pixels of the LCD panel 42. Although the reflective film is provided on the portion of the flat surface 71 ₁ corresponding to the boundary portion, the reflective film need not be provided on the flat surface 71 ₁ . In this case, red light is emitted from the entire plane 71 ₁ .

The red light guide 61 _1, so as to be incident light from the vertex side opposite to the plane 71 _1, in the lower part in the figure, the red light emitting diode 51 ₁ is provided.

Like the red light guide 61 _1, the red light guide 61 ₂ and 61 _3, respectively red light emitting diodes (not shown) is disposed. Then, in the band-like plane 71 ₂ of the red light guide 61 ₂ , regions (parts) having a size corresponding to the red pixels at positions corresponding to the red pixels of the LCD panel 42 are red pixel regions 101 _12, 101 _22. , And 101 ₃₂ . In addition, in the plane 71 ₃ of the red light guide 61 ₃ , regions (parts) of a size corresponding to the red pixels at positions corresponding to the red pixels of the LCD panel 42 are red pixel regions 101 ₁₃ , 101 ₂₃ , and 101 ₃₃ .

The distance between the red light guides 61 ₁ and 61 ₂ is equal to the thickness of the two light guides of the green light guide 62 ₁ and the blue light guide 63 ₁ . Similarly, the distance between the red light guides 61 ₂ and 61 ₃ is also equal to the thickness of the two light guides.

Note that in the case there is no need to distinguish the red light guide 61 _through 613 _3, collectively called red light guide 61. Further, when it is not necessary to distinguish the red pixel areas 101 ₁₁ , 101 ₂₁ , and 101 _31, they are collectively referred to as a red pixel area 101 ₁ . Similarly, when it is not necessary to distinguish the red pixel areas 101 ₁₂ , 101 ₂₂ , and 101 _32, they are collectively referred to as the red pixel area 101 ₂ , and it is necessary to distinguish the red pixel areas 101 ₁₃ , 101 ₂₃ , and 101 _33. If not, that the red pixel region 101 ₃ collectively.

When there is no need to distinguish the red pixel areas 101 _{1 to} 101 _3, they are collectively referred to as the red pixel area 101. Further, when it is not necessary to distinguish the planes 71 _{1 to} 71 _3, they are collectively referred to as the plane 71. The red light emitting diodes arranged in the red light guide 61 are collectively referred to as a red light emitting diode 51.

  The red light emitted by the red light emitting diode 51 enters the red light guide 61, is reflected by the reflection film formed on the surface of the red light guide 61, and is guided to the flat surface 71. The red light guided to the plane 71 is emitted from the red pixel region 101 and irradiated to the corresponding red pixel of the LCD panel 42. Therefore, red color can be displayed in the red pixel of the LCD panel 42 without a color filter.

  Note that the red light emitted from the red pixel region 101 spreads as the distance from the red pixel region 101 increases. Therefore, when the red pixel area 101 and the LCD panel 42 are separated from each other to some extent, the red pixel area 101 has a size in consideration of the above-described spread of light, that is, the red pixel area 101 and the LCD panel. The size is preferably smaller than the pixel according to the distance from the panel 42. However, in the liquid crystal display device 40, as described above, the red pixel region 101 is in contact with the LCD panel 42. Therefore, the size of the red pixel region 101 takes into account the above-described spread of light. For example, even if it is the same size as the pixel of the LCD panel 42, there is no problem. The same applies to the green pixel region 102 and the blue pixel region 103.

Green light guide 62 ₁ is the same as the structure of the red light guide 61. That is, the green light guide 62 ₁ is composed of a triangular acrylic flat plate having a thickness in the band-like plane 72 ₁ (plane E in FIG. 2) corresponding to the pixel and having the base on the plane 72 ₁ side. Yes. On the plane 72 ₁ , areas (portions) having sizes corresponding to the green pixels at positions corresponding to the green pixels of the LCD panel 42 are green pixel areas 102 ₁₁ , 102 ₂₁ , and 102 ₃₁ . Also, the green light guides 62 _1, so as to be incident light from the vertex side opposite to the plane 72 _1, in the lower part in the figure, the green light emitting diode 52 ₁ is provided.

Like the green light guide 62 _1, the green light guide 62 ₂ and 62 _3, respectively green light emitting diodes (not shown) is disposed. Then, in the plane 72 _{and second} band-like green light guide 62 _2, the position corresponding to the green pixel of the LCD panel 42, the size of the area corresponding to the green pixel (portion), the green pixel region 102 _12, 102 ₂₂ , And 102 ₃₂ . _On the plane 72 ₃ of the green light guide 62 ₃ , regions (parts) of a size corresponding to the green pixels at positions corresponding to the green pixels of the LCD panel 42 are green pixel regions 102 ₁₃ , 102 ₂₃ , and 102 ₃₃ .

The distance between the green light guides 62 ₁ and 62 ₂ is equal to the thickness of the two light guides of the blue light guide 63 ₁ and the red light guide 61 ₂ . Similarly, the distance between the green light guides 62 ₂ and 62 ₃ is also equal to the thickness of the two light guides.

Hereinafter, when it is not necessary to distinguish the green light guides 62 _{1 to} 62 _3, they are collectively referred to as the green light guide 62. Further, when it is not necessary to distinguish the green pixel regions 102 ₁₁ , 102 ₂₁ , and 102 _31, they are collectively referred to as a green pixel region 102 ₁ . Similarly, when it is not necessary to distinguish the green pixel regions 102 ₁₂ , 102 ₂₂ , and 102 _32, they are collectively referred to as the green pixel region 102 ₂ , and it is necessary to distinguish the green pixel regions 102 ₁₃ , 102 ₂₃ , and 102 _33. When there is not, it is collectively referred to as a green pixel region 102 ₃ .

Further, when it is not necessary to distinguish the green pixel regions 102 _{1 to} 102 _3, they are collectively referred to as the green pixel region 102. Further, when it is not necessary to distinguish the planes 72 _{1 to} 72 _3, they are collectively referred to as the plane 72. The green light emitting diodes arranged in the green light guide 62 are collectively referred to as a green light emitting diode 52.

  Green light emitted by the green light emitting diode 52 is incident on the inside of the green light guide 62, reflected by the reflection film formed on the surface of the green light guide 62, and guided to the plane 72. The green light guided to the plane 72 is emitted from the green pixel region 102 and irradiated to the corresponding green pixel of the LCD panel 42. Therefore, the green color of the LCD panel 42 can be displayed without a color filter.

The blue light guide 63 ₁ is configured similarly to the red light guide 61. That is, the blue light guide 63 ₁ is formed of a triangular acrylic flat plate having a thickness on the band-like plane 73 ₁ (plane F in FIG. 2) corresponding to the pixel and having the base on the plane 73 ₁ side. Yes. In the plane 73 _1, the position corresponding to the blue pixel of the LCD panel 42, the size of the area corresponding to the blue pixel (portion), there is a blue pixel region 103 _11, 103 ₂₁ and 103 _31,. Further, the blue light guide 63 _1, so as to be incident light from the vertex side opposite to the plane 73 _1, in the lower part in the figure, the blue light emitting diode 52 ₁ is provided.

Similar to the blue light guide 63 _1, the blue light guide 63 ₂ and 63 _3, respectively blue light emitting diode (not shown) is disposed. Then, in the band-like plane 73 ₂ of the blue light guide 63 ₂ , regions (parts) having a size corresponding to the blue pixel at positions corresponding to the blue pixel of the LCD panel 42 are blue pixel regions 103 ₁₂ and 103 _22. , And 103 ₃₂ . _On the plane 73 ₃ of the blue light guide 63 ₃ , regions (parts) having a size corresponding to the blue pixels at positions corresponding to the blue pixels of the LCD panel 42 are blue pixel regions 103 ₁₃ , 103 ₂₃ , and 103 ₃₃ .

The distance between the blue light guides 63 ₁ and 63 ₂ is equal to the thickness of the two light guides of the red light guide 61 ₂ and the green light guide 62 ₂ . Similarly, the distance between the blue light guides 63 ₂ and 63 ₃ is also equal to the thickness of the two light guides.

Note that in the case there is no need to distinguish between the blue light guide 63 ₁ to 63 _3, collectively called the blue light guide 63. In addition, when it is not necessary to distinguish the blue pixel regions 103 ₁₁ , 103 ₂₁ , and 103 _31, they are collectively referred to as the blue pixel region 103 ₁ . Similarly, if there is no need to distinguish between the blue pixel regions 103 _12, 103 _22, and 103 _32, referred to as a blue pixel region 103 ₂ collectively, need to be distinguished from the blue pixel regions 103 _13, 103 _23, and 103 ₃₃ If not, collectively referred blue pixel region 103 _3.

Further, when it is not necessary to distinguish the blue pixel regions 103 _{1 to} 103 _3, they are collectively referred to as the blue pixel region 103. Furthermore, when it is not necessary to distinguish the planes 73 _{1 to} 73 _3, they are collectively referred to as a plane 73. The blue light emitting diodes arranged in the blue light guide 63 are collectively referred to as a blue light emitting diode 53.

  The blue light emitted by the blue light emitting diode 53 is incident on the inside of the blue light guide 63, is reflected by the reflection film formed on the surface of the blue light guide 63, and is guided to the plane 73. The blue light guided to the plane 73 is emitted from the blue pixel region 103 and irradiated to the corresponding blue pixel of the LCD panel 42. Therefore, the blue pixel of the LCD panel 42 can display blue without a color filter.

  The backlight 41 is configured such that the plane 71 of the red light guide 61, the plane 72 of the green light guide 62, and the plane 73 of the blue light guide 63 are arranged on a plane parallel to the display surface of the LCD panel 42. Further, the flat surfaces 71 to 73 are arranged so as to be in contact with the LCD panel 42 (the polarizing plate 21 thereof).

  The red light guide 61 irradiates the red light emitted by the red light emitting diode 51 from the red pixel region 101 having the size of the red pixel at the position of the red pixel of the LCD panel 42, and therefore uses a color filter. In addition, it is possible to reliably irradiate red light on the LCD panel 42 with red light. Similarly, the green light guide 62 irradiates the green light emitted by the green light emitting diode 52 from the green pixel region 102 of the size of the green pixel at the position of the green pixel of the LCD panel 42, so that the color filter is used. Without using it, the green pixels of the LCD panel 42 can be reliably irradiated. The blue light guide 63 irradiates the blue light emitted from the blue light emitting diode 53 from the blue pixel region 103 of the size of the blue pixel at the position of the blue pixel of the LCD panel 42, and therefore uses a color filter. In addition, the blue pixels of the LCD panel 42 can be reliably irradiated.

  Here, for example, when light passes through the color filter and the brightness of the light is attenuated to about 30%, the liquid crystal display device 40 that does not use the color filter is compared with the liquid crystal display device that uses the color filter. In order to display images with the same brightness, the brightness of the light emitted by the light emitting diodes can be reduced to about 1/3 (30%), that is, the number of light emitting diodes can be reduced to about 1/3. it can.

  In the liquid crystal display device 40, the red light of the red light emitting diode 51, the green light of the green light emitting diode 52, and the blue light of the blue light emitting diode 53 are used in the image of the LCD panel 42 without using a color filter. In other words, because it irradiates directly, the red, green, and blue light obtains white light from the red, green, and blue light, and the white light when illuminating the LCD panel with the color filter. About 1/3 of the brightness. Therefore, according to this aspect, the liquid crystal display device 40 has the same brightness as that of a liquid crystal display device that obtains white light from red, green, and blue light and displays an image using a color filter. The number of light-emitting diodes can be reduced to about 1/3 for displaying the above image.

  Further, in the liquid crystal display device 40, the red light of the red light emitting diode 51, the green light of the green light emitting diode 52, and the blue light of the blue light emitting diode 53 are irradiated only to the corresponding color pixels. On the other hand, in the liquid crystal display device 1 including the white light source 11 of FIG. 1, since white light is irradiated to the entire color filter 23, light is irradiated to portions other than the pixels, that is, boundary portions between the pixels, The light applied to the boundary between the pixels does not contribute to the display of the image. Therefore, if the light use efficiency is about 30% when light is also applied to the boundary portion between the pixels of the color filter 23, the boundary of the pixel of the color filter 23 is assumed in the liquid crystal display device 40. Compared with the liquid crystal display device 1 that displays an image by irradiating the part with white light, the number of light emitting diodes is reduced to about 1/3 (about 30%) to display an image having the same brightness. be able to.

  From the above, in the liquid crystal display device 40 that irradiates each pixel of the LCD panel 42 with light of a corresponding color without using a color filter, the light of the red light emitting diode 51, the green light emitting diode 52, and the blue light emitting diode 53. 1 can be drastically improved, and when an image having the same brightness is displayed on the liquid crystal display device 1 of FIG. / 3 × 1/3 × 1/3) of diodes are sufficient.

  As described above, according to the liquid crystal display device 40, the utilization efficiency of light emitted from the red light emitting diode 51, the green light emitting diode 52, and the blue light emitting diode 53 can be remarkably improved. Overall power consumption, calorific value, and production cost can be reduced.

  FIG. 5 is a plan view of the backlight 41 of FIGS. 2 to 4 as viewed from the side (planes 71, 72, 73) in contact with the LCD panel 42.

As shown in FIG. 5, in the first column (first column from the left), the plane 71 ₁ of red light guide 61 ₁ is disposed on the second row, the plane 72 ₁ of the green light guide 62 ₁ are arranged, in the third row, the plane 73 ₁ of the blue light guide 63 ₁ is disposed. Similarly, in the fourth to ninth rows, the plane 71 of the red light guide 61, the plane 72 of the green light guide 62, and the plane 73 of the blue light guide 63 are periodically arranged in the horizontal direction.

Further, in the first row (first row from the top), the plane 71 _first red pixel regions 101 _11, a green pixel region 102 ₁₁ planes 72 _1, the plane 73 ₁ of the blue pixel region 103 _11, plan 71 ₂ the red pixel regions 101 _12, the green pixel region 102 ₁₂ plane 72 _2, blue pixel regions 103 ₁₂ plane 73 _2, the red pixel region 101 ₁₃ plane 71 _3, green pixel regions 102 ₁₃ plane 72 _3, a plane 73 ₃ blue pixel regions 103 ₁₃ are arranged on a straight line in order horizontally from the left in the drawing. Similarly, in the second row and the third row, the red pixel region 101, the green pixel region 102, and the blue pixel region 103 are arranged in a straight line in the horizontal direction.

  By irradiating the LCD panel 22 with red, green, or blue light from the red pixel region 101, the green pixel region 102, or the blue pixel region 103 in FIG. The red pixel, the green pixel, and the blue pixel are periodically arranged in that order, and three red pixels, three green pixels, and three blue pixels are arranged in a straight line in the vertical direction. The displayed image is displayed.

  By the way, in the liquid crystal display device 40 shown in FIGS. 2 to 5, the red light-emitting diode 51 starts from the length in the depth direction of the backlight 41, that is, from the plane D in which light is emitted from the red light guide 61 in FIG. For example, when the distance to the arrangement position of the red light guide 61 is about 30 mm, the red light guide 61 extends from the uppermost red pixel area 101 to the lowermost red pixel area 101 of the red light guide 61. In order to emit light uniformly and uniformly, the length (height) of the plane D in the longitudinal direction needs to be suppressed to about 200 mm.

  Now, assuming that the length in the longitudinal direction of the plane D is about 200 mm, the liquid crystal display device 40 of about 15 inches can be configured with one backlight 41.

  Now, assuming that one backlight 41 that can constitute the liquid crystal display device 40 of about 15 inches is called one unit, a liquid crystal display device with a larger screen can be obtained by using the backlight 41 of a plurality of units. Can be easily configured.

  That is, FIG. 6 shows a backlight 111 of a liquid crystal display device configured using a plurality of units of backlights 41.

  The backlight 111 shown in FIG. 6 includes the backlight 41 composed of a plurality of red light guides 61, green light guides 62, and blue light guides 63 as one unit, and the plurality of units include belt-like planes 71 to 73. They are arranged to be arranged on a plane parallel to the display surface. Here, as described above, the length (height) in the direction of arrow X in the drawing of the backlight 41 as one unit is about 30 mm, and the length (width) in the direction of arrow Y in the drawing is about 200 mm. , Corresponding to about 15 inches.

  As shown in FIG. 6, a large screen liquid crystal display device can be configured by forming the backlight 111 from a plurality of units. For example, by arranging two units in the arrow Z direction and two units in the arrow Y direction to form the backlight 111 with four units, a liquid crystal display device of about 30 inches can be easily configured. be able to.

  FIG. 7 is a perspective view of a configuration example of another embodiment of the backlight 41 to which the present invention is applied. In the figure, parts corresponding to those in FIG. 4 are denoted by the same reference numerals. In FIG. 7, only the components related to red light in the backlight 41 are shown, and the portions related to green light and blue light are not shown.

In FIG. 7, in addition to the _three red light guides 61 _{1 to} 61 ₃ , one red light emitting diode 121 and red light emitted from the red light emitting diode 121 are guided to the red light guides 61 _{1 to} 61 ₃ . A red light emitting diode guide 122 is provided.

  The red light emitting diode 121 shown in FIG. 7 emits red light in the same manner as the red light emitting diode 51 described above. The red light emitting diode 121 is arranged on the red light emitting diode guide 122 so that the emitted red light enters the red light emitting diode guide 122.

  The red light emitting diode guide 122 is formed of a transparent acrylic flat plate, for example, like the red light emitting diode 61, and has a comb shape. Further, a reflective film is formed on the surface of the red light emitting diode guide 122 except for a region (part) where the red light emitting diode 121 is disposed and a region 122A corresponding to the tip of the comb. As a result, the red light emitting diode 121 emits light, and the red light incident on the red light emitting diode guide 122 is guided to the region 122A and emitted only from the region 122A.

  Further, the red light emitting diode guide 122 is configured such that the interval between the regions 122A corresponding to the tips of the combs coincides with the interval between the red light emitting diodes 61, and the region 122A corresponds to the red light emitting diode 61. 4, the red light emitting diode 51 is disposed at a portion where the red light emitting diode 51 is disposed (vertex portion facing the side on the plane D (FIG. 4) side of the triangular red light guide 61).

  Accordingly, in FIG. 7, the red light emitted from the red light emitting diode 121 enters the red light emitting diode guide 122, is guided by the region 122A, and enters the red light guide 61 from the region 122A. In the red light guide 61, the red light incident thereon is guided to the red pixel region 101 (FIG. 4) (not shown in FIG. 7) as in the case of FIG.

  As described above, since the light of one red light emitting diode 121 is guided by the red light emitting diode guide 122 in the three red light guides 61 of FIG. 7, the red light guide 61 is red as shown in FIGS. It is not necessary to arrange the red light emitting diode 51 for each light guide 61, and the number of red light emitting diodes 51 can be reduced. Therefore, the production cost can be reduced.

  In FIG. 7, light emitted from one red light emitting diode 121 is incident on the red light emitting diode guide 122, but light emitted from a plurality of red light emitting diodes 121 is incident on the red light emitting diode guide 122. You may make it inject.

  In the above description, the shapes of the red light guide 61, the green light guide 62, and the blue light guide 63 are substantially triangular. However, the shapes of the red light guide 61, the green light guide 62, and the blue light guide 63 are as follows. It is not limited to a triangle.

  8A to 8C are left side views showing another example of the red light guide 61 (viewed from the direction A in FIG. 2). 8A to 8C, the red light guide 61 will be described, but the same applies to the green light guide 62 and the blue light guide 63.

  As shown in FIGS. 8A to 8C, the red light guide 61 has a narrow surface on which the red light emitting diode 51 is disposed and a wide surface in contact with the LCD panel 42 (a surface opposite to the surface on which the red light emitting diode 51 is disposed). Suehiro shape.

  As described above, in the liquid crystal display device 40, the red light guide 51 is a pixel in which the red light emitted from the red light emitting diode 61 is arranged on a plane parallel to the display surface on which an image is displayed. Since the light is guided to the band-like plane 71 having a width corresponding to, and the red pixel is irradiated, the red pixel can be surely irradiated with the red light without using the color filter.

  Similarly, the green light guide 52 and the blue light guide 53 can reliably irradiate the green pixel with green light and the blue pixel with blue light, respectively. That is, it is possible to reliably irradiate each color pixel with the corresponding color light.

  Further, the red pixel region 101 of the red light guide 61 can be easily formed by coating the surface of the red light guide 61 with a reflective film or the like. In addition, the position and size of the red pixel region 101 may be basically matched with the position and size of the pixel. Therefore, the red light guide 61 can be easily produced. The same applies to the green light guide 62 and the blue light guide 63.

  Furthermore, it is not always necessary to form a reflective film on the plane D (plane 71) of the red light guide 61. In this case, the production of the red light guide 61 can be facilitated. The same applies to the green light guide 62 and the blue light guide 63.

  In FIG. 7, light is guided from the red light emitting diode guide 121 to the three red light guides 61. However, the number of red light guides 61 that guide light from the red light emitting diode guide 121 is as follows. The number can be any number, for example, the number of red light guides 61 constituting one unit or a plurality of units. The same applies to the green light emitting diode guide and the blue light emitting diode guide.

  Furthermore, in the embodiment of the present invention, the liquid crystal display device 40 is configured to display an image composed of pixels of three colors, a red pixel, a green pixel, and a blue pixel, but is composed of pixels of four or more colors. It is also possible to display an image to be displayed. In this case, the backlight 41 may be configured by a light emitting diode that emits light of each of the four or more colors and a light guide that guides the light.

It is sectional drawing which shows the structure of an example of the liquid crystal display device using a white light source. It is a perspective view which shows the structural example of one Embodiment of the liquid crystal display device to which this invention is applied. FIG. 3 is a left side view of the liquid crystal display device of FIG. 2 (viewed from direction A of FIG. 2). It is a perspective view of the backlight in case a backlight is comprised from three red light guides, three green light guides, and three blue light guides. FIG. 5 is a plan view of the backlight of FIGS. 2 to 4 as viewed from the side in contact with the LCD panel. It is a figure which shows the backlight of the liquid crystal display device comprised using the backlight of several units. It is a perspective view which shows other one Embodiment of the backlight to which this invention is applied. It is a left view which shows the other example of a red light guide.

Explanation of symbols

  21 polarizing plate, 22 TFT, 24 liquid crystal, 25 polarizing plate, 40 liquid crystal display, 41 backlight, 42 LCD panel, 51 red light emitting diode, 52 green light emitting diode, 53 blue light emitting diode, 61 red light guide, 62 green light Guide, 63 Blue light guide, 71 plane, 72 plane, 73 plane, 121 red light emitting diode, 122 red light emitting diode guide

Claims (8)

In a backlight of a display device that displays an image composed of an array of at least a first color pixel and a second color pixel,
A first light emitting diode that emits light of a first color;
A second light emitting diode that emits light of a second color;
A band-shaped plane having a width corresponding to the pixel, and the first color light emitted from the first light emitting diode is guided to the band-shaped plane to irradiate the pixel of the first color. A first light guide having a flat plate shape;
The second color light emitted from the second light-emitting diode is guided to the band-shaped plane to irradiate the pixels of the second color. A flat plate-shaped second light guide,
A plurality of the first and second light guides are periodically arranged so that the belt-like plane is aligned on a plane parallel to a display surface on which the image is displayed. Backlight. The image is constituted by an array of pixels of the first color, pixels of the second color, and pixels of a third color,
A third light emitting diode that emits light of the third color;
A band-shaped plane having a width corresponding to the pixel, and the third color light emitted from the third light emitting diode is guided to the band-shaped plane to irradiate the pixel of the third color. And a flat plate-shaped third light guide,
2. The plurality of first to third light guides are periodically arranged so that the belt-like plane is aligned on a plane parallel to the display surface. 3. Back light. The first color is red;
The second color is green;
The backlight according to claim 2, wherein the third color is blue. A fourth light guide for guiding the light of the first color emitted by one first light emitting diode with respect to the plurality of first light guides;
A fifth light guide for guiding light of the second color emitted by one second light emitting diode with respect to the plurality of second light guides;
The sixth light guide for guiding the light of the third color emitted by one third light emitting diode with respect to the plurality of third light guides, further comprising: The backlight described in. The first to third light guides are triangular flat plates having the strip-shaped plane as a thickness and the strip-shaped plane side as a base,
The first to third light emitting diodes are respectively arranged with respect to the first to third light guides so that light enters from a vertex side of the triangular plate opposite to the bottom side. The backlight according to claim 2, wherein: Each of the triangular flat plates as the first to third light guides is arranged such that the first to third light guides are arranged so that the belt-like plane is parallel to the display surface. In such a state, different triangles are formed so that a vertex of the light guide of one of the first to third light guides facing the bottom side is exposed at a position different from a vertex of the other light guide facing the bottom side. The backlight according to claim 5, wherein the backlight is configured in a shape. A plurality of the first to third light guides periodically arranged as one unit, and the plurality of units are arranged so that the belt-like plane is aligned on a plane parallel to the display surface. The backlight according to claim 2, wherein In a liquid crystal display device that displays an image composed of an array of at least a first color pixel and a second color pixel,
A liquid crystal display element;
A backlight for illuminating the liquid crystal display element,
The backlight is
A first light emitting diode that emits light of a first color;
A second light emitting diode that emits light of a second color;
A band-shaped plane having a width corresponding to the pixel, and the first color light emitted from the first light emitting diode is guided to the band-shaped plane to irradiate the pixel of the first color. A first light guide having a flat plate shape;
The second color light emitted from the second light-emitting diode is guided to the band-shaped plane to irradiate the pixels of the second color. A flat plate-shaped second light guide,
The plurality of first and second light guides are periodically arranged so that the belt-like plane is aligned on a plane parallel to the display surface of the liquid crystal display element on which the image is displayed. A liquid crystal display device characterized by the above.

Images