JPH03191328A - Surface liquid crystal display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a planar liquid crystal display device used as a display of a portable type small personal computer or the like.

(Prior Art) Conventionally, this type of display device has been disclosed, for example, in Japanese Patent Application Laid-Open No. 63-309.
As disclosed in Japanese Patent No. 918, etc., and as shown in FIG. 3, a plate-shaped liquid crystal module (D) including a liquid crystal panel has a light diffused reflection surface (F) such as a dot pattern on the back side.
By arranging the plate-shaped backlight module (B) having a light transmitting plate (E) facing each other and arranging the light source (L) on the side of the backlight module (B), the overall thickness can be reduced. By making it as thin as possible to make it smaller and lighter,
This makes it easy to store the device in a thin-walled display case or the like that opens to the main body that includes the keyboard.

Also, normally, the flat surface on the front side of the light transmitting plate (E) is used to uniformize the light diffusely reflected by the diffusely reflecting surface (F) on the back surface and transmit it to the liquid crystal panel in front, as shown by the imaginary line in Fig. 3. For irradiation, a light diffusing plate (G
). Furthermore, the LSI etc. that constitute the drive element (A) of the liquid crystal panel are mounted on a printed circuit board CP> disposed on the back side of the light transmitting plate (E), and the printed circuit board (P) and the liquid crystal module (D) A flexible tube (K) or the like is used to connect the two.

(Problem to be Solved by the Invention) However, in the above conventional structure, first of all, the driving element (A) is mounted using a printed circuit board (P), and this printed circuit board (P) is mounted on a light transmitting plate (E). ), the overall thickness becomes thicker by the amount that the substrate (P) is placed on the back side, and there is a problem in that there is a limit to how thin the substrate (P) can be made. In this point,
Place the printed circuit board (P) on the back side of the light transmitting plate (E),
They are arranged on the outer side of the transparent plate (E) or, for example, inside the main body case on the keyboard side, and these external parts are connected between the substrate and the liquid crystal module (D) by a flexible tube (K).
), but even if there is an improvement in the thickness of the display case, the flat surface of the case may become wider, or other cases may become larger, resulting in new problems in other areas. The disadvantage is that it imposes size constraints.

Secondly, since only one light diffusing plate (G) is inserted, there is a limit to how thin the light transmitting plate (E) can be made.
Also from this point of view, there is a limit to reducing the overall thickness. In other words, as the light transmitting plate (E) becomes thinner, the diffuse reflection surface (F) such as a dot pattern formed on the back surface becomes thinner than the light diffusing plate (G).
) and the thickness of the light transmitting plate (E) and appear on the back of the liquid crystal panel, making the screen extremely difficult to see, especially if they appear behind small letters. Therefore, it is necessary to ensure the thickness of the light transmitting plate (E) to a certain extent or more, which increases the overall thickness.

Therefore, the existing conventional type has a structure in which the printed circuit board is placed on the back, and the total thickness including the outer frame case is approximately 10 m.
8.5mm even when using the m s T A B type
was considered to be the limit, and it was not possible to make the thickness any thinner than this.

The purpose of the present invention is to reduce the thickness of the element mounting surface by adopting a new structure in which driving elements are directly mounted on the liquid crystal module, and to reduce the thickness of the light transmitting plate by improving the backlight part. As a result, the overall thickness has been further reduced to 7m, which has been coveted in the industry for some time.
It is an object of the present invention to provide a planar liquid crystal display device that can meet the requirement of less than m.

(Means for Solving the Problems) Therefore, in order to achieve the above object, the present invention provides a substrate (
A plate-shaped liquid crystal module (4) in which a liquid crystal panel (5) and a driving element (6) of the liquid crystal panel (5) are arranged in a plane.
1), and a thin light transmitting plate (7) having a flat surface (71) on the front surface and a diffusely reflecting surface (72) on the back surface is disposed on the back side of the liquid crystal module (1) to reduce the light transmission. A reflective plate (8) is placed on the diffused reflection surface (72) side of the plate (7),
71) A plurality of light diffusing plates (9a) and (9b) are laminated and brought into close contact with each other, and a light source is provided on the side end side of the light transmitting plate (7) for irradiating light to the transmitting plate (7). We decided to install (3).

(Function) The liquid crystal panel (5) and the driving element (6) of the liquid crystal panel (5)
) on the board (4), it is possible to eliminate the need for the thickness of the printed circuit board conventionally used for mounting the elements, the thickness of the elements mounted on the board, and the clearance for insulation. . Also, a light diffusion plate (9a)
By making (9b) a plurality of sheets, the light transmitting plate (
Even if the diffused reflection surface (72) on the back surface is seen through the lower layer light diffusion plate (9a) by thinning the layer 7), the diffused reflection surface (72) reflected behind it can be seen through the light diffusion plate (9b) layered on the upper layer. )
This allows the light transmitting plate (7) to be made thinner.

(Example) The planar liquid crystal display device shown in FIG. 2 is housed in, for example, an open-lid display case of a personal computer, and a backlight module (2) is installed on the back of the liquid crystal module (1). is arranged, and a light source (3) is arranged on the side of the backlight module (2).

The liquid crystal module (1) has two glass plates (41).
Stack (42) on a sandwich board and attach the ends to the holder (
43) A substrate (4) held by (44) is provided, and the substrate (4) is
A liquid crystal panel (5) is disposed in the center of the plane of the liquid crystal panel (4), and the glass plate (41
) (42), the drive element (6) of the panel (5)
A large number of LSI chips (60) constituting a The so-called COG method (chlp onglass method) is adopted in which connections are made using a wiring pattern formed on the surface.

The backlight module (2) also has a flat surface (71) on the front side facing the liquid crystal module (1).
There are many dots on the back side due to screen printing, etc.) (
A light transmission plate (7) made of a thin transparent acrylic plate each having a light diffused reflection surface (72) formed with a shape 72a) is provided, and on the side of the light transmission surface (72) of the light transmission plate (7), A reflective plate (8) made of a white sheet with high reflectance or the like is brought into close contact with the light diffusing sheet, and two sheet-like light diffusion sheets are provided on the flat surface (71) side with unevenness such as a pear pattern on the surface to form a frosted glass shape. The plates (9a) and (9b) are laminated and brought into close contact. The liquid crystal module ( 1) are arranged opposite to each other on the back side.

Further, the light source (3) uses, for example, a cold cathode tube, and is disposed outside the short side end of the light transmitting plate (7) constituting the backlight module (2). The light transmission plate (7) is irradiated with light from the side.

As clearly shown in FIG. 1, each of the above-mentioned parts is housed in an outer frame case (work 0), and is further covered by a decorative display case (not shown).

In addition, between the outer frame case (10) and the liquid crystal module (1) and between the outer frame case (10) and the reflective surface (8), a spacer (made of double-sided tape or the like similar to the above spacer) is provided. 13) (15) is interposed. Also, light source (3)
The outer periphery of the film is made of flexible plastic film (32).
A silver film (33) is pasted on the inner surface of the backlight module (2), or a reflector (34) is interposed therebetween, and the ends of the reflector (34) are adhered to the front and rear surfaces of the backlight module (2). Light from the light source (3) is guided to the transmission plate (7).

In this way, as in the above configuration, first the liquid crystal panel (5)
As described above, since the drive element (6) is directly mounted on the board (4) using the COG method, for example, the thickness conventionally required on the element mounting surface, that is, the thickness of the printed circuit board and the elements mounted on the board, is reduced. This eliminates the need for a thickness such as a clearance for insulation and a thickness for insulation, so the wall thickness can be made that much thinner.

Secondly, since the light diffusing plates (9a) and (9b) are configured with a plurality of sheets, it is possible to reduce the thickness of the light transmitting plate (7). By thinning the wall,
Furthermore, the overall thickness can be made thinner. In other words, when two light diffusing plates are provided, since the pear pattern is formed on the surface of each light diffusing plate (9a) (9b), the light diffusing plate (7) is made thinner and the light of the first one is Dots (7
Even if 2a) is captured, the second light diffusing plate (9b) layered on top of it will obscure the dot (7) that appears behind it.
2a) can be hidden, and since there is no problem in making the light transmitting plate (7) thinner, it is possible to further reduce the thickness. In addition, two light diffusing plates (9a) (9b)
), if the illuminance of the light irradiated to the liquid crystal panel (5) decreases slightly, this can be compensated for by slightly increasing the gas pressure of the light source (3) compared to the conventional one-panel configuration.

As described above, thinning of the element mounting surface and light transmitting plate (7
) can be made thinner, so the overall thickness including the outer frame case (10) and each spacer (13, 14, 15) can be made even thinner than the conventional one.

By the way, to give specific figures, the thickness of the liquid crystal module (1) including the liquid crystal panel (5) and drive element (6) is 2.2 mm, and the thickness of the light transmitting plate (7) is as thin as 1.8 mm. In addition, the thickness of each light diffusing plate (9a) (9b) and reflection plate (8) is 0.25 mm, the thickness of each spacer (13) (14) (15) is 0.4 mm, and the outer frame case ( Even if the plate thickness of 10) is added to 0.3 mm, the total thickness remains at 6.55 mm, making it possible to make the overall thickness extremely thin, meeting the industry's long-held requirement of a total thickness of 7 mm or less.

Therefore, the openable display case can be made thinner and lighter, making it extremely convenient to carry and use the personal computer.

In the embodiment described above, glass plates (41) and (42) are used as the substrate (4) of the liquid crystal module (1), and the drive element (6) is mounted on this glass plate.
method, but using other materials instead of glass plates,
With a structure other than the COG method, the drive element (6) is connected to a liquid crystal panel (
5) may be implemented in a two-dimensional manner.

In addition to using double-sided tape as the spacers (13), (14), and (15), for example, anisotropically conductive rubber may be used.

Further, although only one light source (3) was disposed on the outside of the short side of the backlight module (2) and thus the light transmitting plate (7), two light sources (3) were installed, one on each side of the short side. Alternatively, one or two may be arranged on the outside of the long side, or four
The arrangement may be in any combination, such as on one side or on any three sides.

(Effects of the Invention) As described above, the present invention provides the liquid crystal panel (5) and the liquid crystal panel (5).
) and the drive element (6) are disposed on the substrate (4) in a flat manner, making it possible to reduce the thickness of the element mounting surface, and also to have a plurality of light diffusing plates (9a) (9b). As a result, we were able to reduce the thickness of the light transmitting plate (7), so the overall thickness could be reduced compared to that of a conventional structure with a printed circuit board placed on the back or T.
It can be made even thinner than those using the AB method,
It can meet the demand for a layer thickness of 7 mm or less, which has long been desired in the industry, and can also be lightweight, making it extremely advantageous for application to display devices for small personal computers.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a planar liquid crystal display device according to the present invention, FIG. 2 is an exploded perspective view of the same, and FIG. 3 is a sectional view of a conventional example. (1)...Liquid crystal module (3)...Light source (4)...Substrate (5)...Liquid crystal panel (6)...Drive element (7)... Light transmission plate (8)...Reflection plate (71)...Flat surface (72)...Diffuse reflection surface

Claims (1)

[Claims] (1) The liquid crystal panel (5) and the liquid crystal panel (
A plate-shaped liquid crystal module (1) in which drive elements (6) of 5) are arranged in a plane, and a flat surface (71) on the front surface and a diffused reflection surface on the back surface of the liquid crystal module (1) is provided on the back side of the liquid crystal module (1). (72
) is arranged, and a reflection plate (8) is placed on the diffused reflection surface (72) side of this light transmission plate (7),
A plurality of light diffusing plates (9a) (9) are provided on the flat surface (71) side.
b) are laminated and brought into close contact with each other, and a light source (3) for irradiating light onto the light transmitting plate (7) is disposed on the side end side of the light transmitting plate (7). LCD display device.