JP3251241B2 - Liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to office automation (OA) for personal computers and the like.
The present invention relates to a liquid crystal display device suitable for use as a display device in equipment.

[0002]

2. Description of the Related Art In general, this type of liquid crystal display device includes a liquid crystal display panel (LCD) for displaying characters and images, and a backlight for illuminating the back surface (back surface) of the LCD. ing. Conventionally, as this type of liquid crystal display device, one shown in FIGS. 5 and 6 has been employed. In the figure, the liquid crystal display device denoted by reference numeral 51 is L
A CD 52, a circuit board 53 and a backlight 54 are provided. The LCD 52 is composed of a transmissive liquid crystal display panel, and a display unit 52 for displaying characters and images is provided on the panel surface side.
a.

[0003] The circuit board 53 has a first circuit board 53a and a second circuit board 53b. First circuit board 53
“a” is a frame-shaped rigid substrate that is entirely opened in the vertical direction, and is disposed on the back side of the LCD 52. On the front surface side of the first circuit board 53a, a number of conductive parts (not shown) corresponding to the respective electrodes of the LCD 52 are formed, and a number of electronic components 53A connected to these conductive parts are mounted. . The second circuit board 53b is made of a flexible board, and is connected to the electrodes of the LCD 52 and the conductive portion of the first circuit board 53a.

[0004] The backlight 54 includes a diffusion plate 54a located in the light-emitting area opposite to the rear surface of the panel, and a diffusion plate 5a.
It has a light source 54b for projecting illumination light toward 4a and illuminating the rear surface of the panel. The light source 54b is disposed on the rear surface side of the LCD 52 and housed in the circuit board 53. Note that, in FIG. 6, the symbol X indicates a display area of the display unit 52 a on the LCD 52, and A and B indicate viewing positions with respect to the LCD 52.

In the liquid crystal display device configured as described above, when a character or an image is displayed on the display section 52a of the LCD 52, the display surface whose brightness is increased by the illumination light projected from the backlight 54 to the rear surface of the panel. Characters and images on 52a can be visually recognized.

[0006]

However, in this type of liquid crystal display device, the external dimensions of not only the LCD 52 but also the backlight 54 tend to be shortened due to the recent demand for light weight and small size. It is difficult to set the outer dimensions of the diffusion plate 54a to a size sufficiently larger than the display area X of the LCD 52. That is, in the conventional liquid crystal display device, as the size of the LCD is reduced, the diffusion surface of the diffusion plate 54a is
The size is set according to the size of

As a result, as shown in FIG.
When the edge of the display portion of the display section 52a is viewed from the viewing position A near the position above the edge of the display portion, the viewing position A and the light emitting area of the backlight 54 are optically coupled. That is, the illumination light from the light source 54b reaches the viewer after passing through the diffusion plate 54a and the LCD 52. Therefore, characters and images on the display unit 52a can be visually recognized as clear characters and images. However, when the display position edge is viewed from the viewing position B where the inclination angle with respect to the display unit 52a is gentler than the viewing position A, the illumination light from the light source 54b does not reach the viewer. Cannot be visually recognized as clear characters and images, and there is a problem in that the reliability in visually recognizing the characters and images decreases.

Japanese Patent Application Laid-Open Nos. 9-212451 and 10-39115 disclose "backlight device and liquid crystal display device, liquid crystal television and viewfinder using the device" and "prism lens sheet and backlight", respectively. Prior art is disclosed as "system and liquid crystal display device", but the above-mentioned problem has not been solved.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid crystal display device capable of expanding a light emitting area by a backlight and thereby improving the reliability of character and image viewing. And

[0010]

According to a first aspect of the present invention, there is provided a liquid crystal display device comprising: a transmission type liquid crystal display panel having a display unit for displaying characters and images on a front surface side; A liquid crystal display device provided with a diffusion plate disposed on the back surface side of the liquid crystal display panel and facing the back surface of the panel, and a backlight having a light source for projecting illumination light toward the diffusion plate and illuminating the back surface of the panel; In the above
A reflector that reflects the illumination light from the light source to the back side of the panel,
Between the liquid crystal display panel and the backlight.
Therefore, it is configured to be disposed above the diffusion plate . did
As a result, the edge of the display location is largely separated from the edge of the display location.
Even if viewed from the viewing position above the display area
After the illumination light from the light is reflected by the reflector on the diffuser
The light passes through the liquid crystal display panel and reaches the viewer.

[0011]

According to a second aspect of the present invention, the reflector is formed integrally with the case of the backlight.
Therefore, even if the edge of the display location is viewed from a viewing position above the display location which is largely separated from the edge of the display location, the illumination light from the backlight is transmitted through the liquid crystal display panel after being reflected by the reflector of the case in the backlight. And reach the viewer.

According to a third aspect of the present invention, the reflector is formed by a square frame. Therefore, even if the display location edge is viewed from a viewing position above the display location that is greatly separated from the display location edge, the liquid crystal display panel is not reflected after the illumination light from the backlight is reflected by the reflector formed of the square frame. To reach the viewer.

According to a fourth aspect of the present invention, the reflector is formed by a circular frame. Therefore, even if the display location edge is viewed from a viewing position above the display location that is greatly separated from the display location edge, the liquid crystal display panel is not reflected after the illumination light from the backlight is reflected by the reflector formed of the circular frame. To reach the viewer.

According to a fifth aspect of the present invention, the reflecting surface of the reflector comprises a reflecting surface inclined outward with respect to a direction perpendicular to the diffusing surface of the diffusing plate. Therefore, even if the display location edge is viewed from a viewing position above the display location that is greatly separated from the display location edge, the illumination light from the backlight is inclined outward with respect to a direction perpendicular to the diffusion surface of the diffusion plate. After being reflected by the reflection surface, the light passes through the liquid crystal display panel and reaches the viewer.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a liquid crystal display device according to a first embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view illustrating an M portion of the liquid crystal display device according to the first embodiment of the present invention, and FIG. 5 is a perspective view showing a reflector used in the liquid crystal display device according to the first embodiment of the present invention. In these drawings, the same members as those in FIGS. 5 and 6 are denoted by the same reference numerals, and detailed description is omitted. I do. 1 to 3, the liquid crystal display device denoted by reference numeral 1 includes an LCD 52, a circuit board 53, a backlight 54, and a reflector 2.

The reflector 2 is composed of a rectangular frame having two sets of large and small rectangular reflecting surfaces 2a and 2b facing each other, disposed on the back side of the LCD 52, and provided by a diffusion plate 54a. Mounted on the surface. As a result, when the illumination light from the light source 54b passes through the diffusion plate 54 and is reflected by the reflection surfaces 2a and 2b toward the rear surface of the LCD 52, the reflected light passes through the LCD 52, and the characters and images on the display 52a are clear. It is visually recognized as a character or image. That is, since the light emitting area of the backlight 54 is expanded by the reflector 2, the viewer at the viewing position B as well as the viewing position A and the light source 54b of the backlight 54 are optically coupled via the display unit 52a.

Although the reflector 2 in this embodiment has been described as being a rectangular frame, the present invention is not limited to this, and may be a circular frame. That is, in short, any illumination light may be used as long as the illumination light from the light source 54b transmitted through the diffusion plate 54a is reflected by the reflector toward the rear surface of the LCD 52. Also, the light source 54b is not particularly limited, and for example, a fluorescent lamp, an electroluminescence lamp, or the like is used.

The case where characters and images on the display section 52a are visually recognized from the visual recognition positions A and B in the liquid crystal display device thus configured will be described with reference to FIG. “Visual recognition from visual recognition position A” (1) As shown in the figure, when the user visually recognizes the vicinity of the edge of the display location on the display unit 52a located diagonally below the visual recognition position A, the illumination light from the light source 54b diffuses. Board 54a, LCD5
2 to sequentially reach the viewer through the display unit 52a.
The upper characters and images are visually recognized as clear characters and images.

(2) LC located immediately below viewing position A
When viewing the display section 52a at D52, the light source 54
Since the illumination light from b reaches the back surface of the LCD 52 after passing through the diffusion plate 54 as in the case of (1), the display unit 5
Characters and images on 2a are visually recognized as clear characters and images. (3) When a display location on the display unit 52a located in an oblique direction having an inclination angle smaller than the inclination angle with respect to the display unit 52a in the case of (1) is visually recognized, the illumination light from the light source 54b passes through the diffusion plate 54a and the LCD 52. Although the light does not reach the viewer even if transmitted, the illumination light from the diffusion plate 54a is reflected by the reflection surface 2a of the reflector 2, and the reflected light is
2 and reaches the viewing position A through the display unit 5.
Characters and images on 2a are visually recognized as clear characters and images.

"Visual recognition from visual recognition position B" (1) As shown in the figure, when the user visually recognizes the edge of the display area on the display section 52a located diagonally below the visual recognition position B, the illumination light from the light source 54b is generated. After transmitting through the diffusion plate 54a, the light is reflected by the reflection surface 2a of the reflector 2 and reaches the rear surface of the LCD 52, so that characters and images on the display unit 52a are clear.
It is visually recognized as an image. (2) When the display location on the display unit 52a located immediately below the viewing position B is visually recognized, the illumination light from the light source 54b reaches the rear surface of the LCD 52 after passing through the diffusion plate 54, and thus the characters on the display unit 52a are displayed. And images are visually recognized as clear characters and images.

(3) Viewing position B The viewing position on the display section 52a, which is located in an oblique direction and has an inclination angle larger than the inclination angle in the case of (1), is visually recognized from the light source 54b as in the case of (2). Since the illumination light reaches the back surface of the LCD 52 after passing through the diffusion plate 54, characters and images on the display unit 52a are visually recognized as clear characters and images. In this way, characters and images on the display unit 52a can be visually recognized from the visual recognition positions A and B.

Therefore, in the present embodiment, since the light emitting area of the backlight 54 can be surely expanded, clear characters and images can be visually recognized over a wide area.

Next, according to a second embodiment of the present invention, FIG.
This will be described with reference to FIG. FIG. 4 is a sectional view showing a liquid crystal display device according to a second embodiment of the present invention. In FIG. 4, the same members as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. In the figure, the liquid crystal display device indicated by reference numeral 41 is:
An LCD 52, a circuit board 53, a backlight 54, and a reflector 42 are provided.

The reflector 42 has a reflection surface 42a which is inclined outward with respect to a direction perpendicular to the diffusion surface of the diffusion plate 54a. Thereby, the illumination light from the light source 54b is
4 and is reflected by the reflection surface 42a to the back side of the LCD 52, the reflected light is transmitted through the LCD 52 and
Characters and images on a are visually recognized as clear characters and images.

In this case, the light emitting area of the backlight 54 is widened by an amount corresponding to the inclination of the reflecting surface 42a.
After the illumination light from 4b passes through the diffusion plate 54a, it is reflected by the reflection surface 2a of the reflector 2 and reaches the back surface of the LCD 52,
Characters and images on the display unit 52a can be visually recognized as clear characters and images over a wider area.

Further, in the present embodiment, since the light emitting area of the backlight 54 is expanded by that much, the outer dimensions of the diffusion plate can be shortened, so that the overall size of the device can be reduced.

In this embodiment, the reflectors 2 and
Although the case where 42 is mounted on the diffusion plate 54a of the backlight 54 has been described, the present invention is not limited to this.
Even in the case of the second embodiment, the same effect as that of the embodiment can be obtained even if it is formed integrally with the case of the backlight 54. in this case,
The formation of the reflector is performed by providing a frame-shaped extension with a reflective surface protruding toward the LCD 52. In addition, in the present invention, a reflector may be attached to the back surface of the liquid crystal display panel 52 if the light emitting area of the backlight 54 is widened.

In this embodiment, the case where the present invention is applied to an OA device such as a personal computer has been described. However, the present invention is not limited to this, and can be applied to a word processor. The present invention is also applicable to electronic devices such as telephones and telephones as in the embodiment.

[0030]

As described above, according to the present invention, a transmissive LCD having a display unit for displaying characters and images on its front surface, a diffusion plate facing the back surface of the panel, and A reflector that reflects the illumination light from the light source to the panel back side is disposed between the backlight and the backlight having a light source that projects the illumination light and illuminates the panel back side. Even when viewed from a viewing position above the display location that is greatly separated from the edge of the location, the illumination light from the backlight is reflected by the reflector, passes through the liquid crystal display panel, and reaches the viewer.

Therefore, since the light emitting region of the backlight can be surely expanded, clear characters and images can be visually recognized over a wide area, and the reliability of character and image recognition can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 illustrates a liquid crystal display device according to a first embodiment of the present invention;
It is sectional drawing which expands and shows a part.

FIG. 3 is a perspective view showing a reflector used in the liquid crystal display device according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a liquid crystal display device according to a second embodiment of the present invention.

FIG. 5 is a perspective view showing a conventional liquid crystal display device.

FIG. 6 is a sectional view showing a conventional liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Reflector 2a Reflection surface 52 LCD 53 Circuit board 54 Backlight 54a Diffusion plate 54b Light source A, B Viewing position

Claims (5)

(57) [Claims] 1. A transmissive liquid crystal display panel having a display section for displaying characters and images on the front side thereof, a diffusion plate disposed on the back side of the liquid crystal display panel and opposed to the back side of the panel. A backlight having a light source for projecting illumination light toward the rear surface of the panel to illuminate the rear surface of the panel, wherein the reflector reflects illumination light from the light source toward the rear surface of the panel.
Between the liquid crystal display panel and the backlight.
And a liquid crystal display device disposed above the diffusion plate . Wherein the reflector, the liquid crystal display device according to claim 1, characterized in that formed in the case and integral of the backlight. Wherein the reflector of liquid crystal display device according to claim 1 or 2, wherein the formed by frame corner shape. Wherein said reflector and liquid crystal display device according to claim 1 or 2, wherein the formed by a circular frame body. Reflective surface of claim 5, wherein said reflector is any one according of claims 1-4, characterized in that a reflecting surface inclined outwardly relative to the diffusion surface perpendicular direction of the diffusion plate Liquid crystal display device.