JPH0327018A - Transmissive liquid crystal display device - Google Patents

Abstract

PURPOSE:To allow the packaging of a driving circuit with high reliability and to assure good visibility by sticking the polarizing plate on a back light side to the diffusion plate between a light source and the liquid crystal element. CONSTITUTION:The upper polarizing plate 2a is stuck onto the upper surface of iransparent liquid crystal element 1 and the lower polarizing plate 2b is not stuck to the liquid crystal element 1 and is stuck onto the surface of the diffusion plate 5 disposed between the light source 3 and the liquid crystal element 1. The packaging of a liquid crystal driving LSI to the liquid crystal element 1 is, therefore, executed with substantially no restriction thereon. The packaging is thus executed with the high reliability. Since the lower polarizing plate 2b is stuck onto the diffusion plate and the upper polarizing plate 2a onto the transparent substrate, the flatness of the polarizing plates is assured and the display visibility is improved.

Description

[Detailed Description of the Invention] Industrial Field of Application Conventional Technology In recent years, display devices such as video equipment such as liquid crystal televisions, information equipment such as word processors and personal computers have been making use of their lightweight and thin features. As a result, liquid crystal display devices have come into widespread use. In addition, as a recent trend, as the brightness of liquid crystal display screens has improved and color has become available, there has been an increase in the number of transmissive liquid crystal display devices with built-in backlights. 4 and 6 show cross-sectional structures of these conventional transmission type liquid crystal display devices, and will be explained below using the drawings.

FIG. 4 shows a conventional single-layer transmission type liquid crystal display device. A polarizing plate 2& and a lower polarizing plate 2b are each attached. or,
A light source 3 such as a fluorescent tube and a reflector 4 are installed below the lower polarizing plate 2b.
A backlight 6 including a diffuser plate 6 and a diffuser plate 6 is arranged. FIG. 5 shows a conventional two-layer transmissive liquid crystal display device.
Another liquid crystal display element 7 is arranged between the upper polarizing plate 2a and the upper polarizing plate 2a. In the case of this two-layer type, the lower liquid crystal display element 1 is called a drive cell, and the upper liquid crystal display element 7 is called a compensation cell. Further, the driving cell 1 and the compensation cell 7 have liquid crystals twisted in opposite directions. and,
The upper polarizing plate 2& is attached to the upper surface of the compensation cell 7, and the lower polarizing plate 2b is attached to the lower surface of the drive cell 1. Further, a backlight 6 similar to the conventional example shown in FIG. 4 is arranged below the lower polarizing plate 2b.

Problems to be Solved by the Invention Normally, a polarizing plate is attached to a liquid crystal display element before a liquid crystal drive circuit is mounted. However, since the conventional transmissive liquid crystal display device described above is of a transmissive type, the liquid crystal drive circuit is increasingly mounted around the liquid crystal display element. For example, a method in which a driving LSI is mounted on a film carrier and connected to the electrode terminals of the liquid crystal display element (chip-on flexible board mounting, abbreviated as COF mounting), or
A method of directly connecting a driving LSI to the electrode terminals of the liquid crystal display element (chip-on-glass mounting, abbreviated as COG mounting) has been adopted.

However, when performing the above-mentioned coy mounting or COG mounting, it is often inconvenient for mounting if a polarizing plate is first attached to the liquid crystal display element.

In the case of COF mounting, the film carriers are connected by thermocompression bonding, so if you are not careful about the difference in the thickness of the polarizing plate, you may break the liquid crystal display element, or the polarizing plate may be damaged by mechanical shock during mounting. It can also be damaged by scratches or solvent damage.

Furthermore, in the case of COG mounting, heat treatment at 100° C. or higher may be required in a post-process, and there is a problem that heat treatment cannot be performed if a polarizing plate is attached.

However, if the drive LSI is mounted on a COF or COG
It is also generally difficult to attach it to a liquid crystal display element after mounting.

For this reason, usually a polarizing plate is attached first, or a polarizing plate without adhesive is simply placed instead of attaching a polarizing plate, although this poses a problem in terms of display visibility.

In view of the above problems, the present invention has been developed without being subject to any restrictions in mounting a transmissive liquid crystal display element, and even after arranging a polarizing plate.
It is an object of the present invention to provide a liquid crystal display device with no problem in display visibility.

Means for Solving the Problems In order to achieve the above object, the present invention provides a method in which a polarizing plate on the backlight side of a transmissive liquid crystal display element having a backlight is disposed between a light source and the transmissive liquid crystal display element. It is characterized by being attached to the surface of the diffuser plate.

Alternatively, it is characterized in that a polarizing plate used on the upper surface side of a transmissive liquid crystal display element having a backlight is attached to a transparent substrate and disposed between the transmissive liquid crystal display element and the transmissive liquid crystal display element.

Effects According to the present invention, since the drive LSI can be mounted without attaching a polarizing plate to the transmissive liquid crystal display element, there are almost no restrictions on mounting, and highly reliable mounting is possible. Since the lower polarizing plate is attached to the casing and the diffuser plate surface, and the upper polarizing plate is attached to the transparent substrate, the flatness of the polarizing plate is ensured and display visibility is improved.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure shows a cross-sectional structure of a transmissive liquid crystal display device according to the first embodiment of the present invention, in which an upper polarizing plate 2& is attached to the upper surface of a liquid crystal display element 1, and a lower polarizing plate 2b is used for liquid crystal display. It is not attached to the element 1, but is attached to the upper surface of the diffuser plate 6 of the backlight 6.

1. FIG. 2 shows a cross-sectional structure of a transmission type liquid crystal display device according to a second embodiment of the present invention, in which an upper polarizing plate 2a of a liquid crystal display element 1 is attached to the lower surface of a transparent substrate 8. , are arranged on the upper surface of the liquid crystal display element 1. Also, lower polarizing plate 2
b is attached to the upper surface of the diffuser plate 6 of the backlight 6 and placed on the lower surface of the liquid crystal display element 1, as in the first embodiment. The transparent substrate 8 to which the upper polarizing plate 2& is attached has a thickness of O. A glass substrate of about S to 3, or an acrylic resin or other resin substrate with excellent light transmittance may be used.

Furthermore, FIG. 3 shows a cross-sectional structure of a two-layer transmission type liquid crystal device according to a third embodiment of the present invention, and as shown in the conventional example, the drive cell 1 and the compensation cell 7 are It is composed of a layer of liquid crystal display elements. The upper polarizing plate 2 & disposed on the upper surface of the compensation cell 7 is attached to the lower surface of the transparent substrate 8 and is disposed in a state of being sandwiched between the compensation cell 7 and the upper polarizing plate 2&. Further, the lower polarizing plate 2b disposed on the lower surface of the drive cell 1 is attached to the upper surface of the diffuser plate 6 of the backlight 6, as in the first embodiment.

Effects of the Invention As described above, according to the present invention, a liquid crystal driving LSI can be mounted without directly attaching one or both of the two polarizing plates arranged on the upper and lower surfaces of the liquid crystal display element. If it is not attached, reliable and reliable implementation will be possible with almost no restrictions. Also, problems such as damage to the polarizing plate during mounting are eliminated.

Furthermore, the flatness of the polarizing plate is improved by attaching the lower polarizing plate to the diffuser plate surface, and attaching the upper polarizing plate to the transparent substrate, so that the upper and lower polarizing plates are sandwiched between them and the liquid crystal display element. This ensures good display visibility. Further, since the upper polarizing plate is disposed on the lower surface of the transparent substrate, the transparent substrate serves as a protective resin substrate for the upper polarizing plate and can protect the polarizing plate or the liquid crystal display element from mechanical external force.

[Brief explanation of drawings]

1 to 3 are cross-sectional views of transmissive liquid crystal display devices according to first to third embodiments of the present invention, and FIGS. 4 and 5 are cross-sectional views of conventional transmissive liquid crystal display devices. 1...Liquid crystal display element (drive cell), 2&...
...Upper polarizing plate, 2b...Lower polarizing plate, 3...
... Light source, 4 ... Reflection plate, 5 ... Diffusion plate, 6 ... Backlight, 7 ... Liquid crystal display element (compensation cell), 8...Transparent substrate. f −−− O−・− 26 −−− 3 1114 −・− 5 −・− 6 −−− Ura crystal cover element J: partial f. 4! i Lower ll & traditional scolding Yutan II In Tawara E Toriso IC-J Crite Figure 3 l Figure 2 Figure

Claims (4)

[Claims] (1) A transmissive type, characterized in that a polarizing plate on the backlight side of a transmissive liquid crystal display element having a backlight is attached to a surface of a diffuser plate disposed between a light source and the transmissive liquid crystal display element. LCD display device. (2) A transmissive liquid crystal display characterized in that a polarizing plate used on the upper surface side of a transmissive liquid crystal display element having a backlight is attached to a transparent substrate and disposed between the transmissive liquid crystal display element and the transmissive liquid crystal display element. Device. (3) The transmissive liquid crystal display device according to claim 1 or 2, wherein the transmissive liquid crystal display element has a two-layer structure including a drive cell and a compensation cell having mutually opposite twist angles. (4) Transparent substrate with non-glare treated surface 0.5~
3. The transmission type liquid crystal display device according to claim 2, wherein the transmissive liquid crystal display device is a glass substrate or a resin substrate with a thickness of 3 mm.