JPS61148430A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To enlarge an angle of view field of a liquid crystal display device by laying a transparent plate provided with prismatic fine projections on a polarizing plate at the view side and scattering the transmitted light through the polarizing plate. CONSTITUTION:Incident light is polarized by a polarizing plate 1a and introduced into a liquid crystal 3 through glass 2a. The liquid crystal 3 acquires rotatory power by the effect of electric field because the molecules of the liquid crystal are twisted by 90 deg. and oriented. The light is rotated by 90 deg. along the molecular axis and is transmitted through a polarizing plate 1b after passing through a glass plate 2b. A transparent mat 4 provided with small prismatic projections 5 are formed on the polarizing plate 1b which scatters the transmitted light by the prisms 5. By the presence of the scattering means, the display device is made more easily visible.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a display device using liquid crystal.

[Conventional technology] A typical liquid crystal display device is shown in FIG.

The incident light is polarized when it passes through the polarizing plate 1a, and becomes light with a certain plane of polarization. The polarized light enters the liquid crystal 3 through the glass 2a. Due to the nature of liquid crystals, when an electric field is applied, liquid crystal molecules are twisted 80 degrees and oriented, resulting in optical rotation. Therefore, the light propagates along the molecular axis and is rotated by 30 degrees. Thereafter, the light passes through the glass 2b and reaches the polarizing plate 1b. Polarizing plate 1b
If the polarization axis of is 80 degrees different from that of the polarizing plate 1a, when an electric field is applied, the light that has passed through the polarizing plate 1a will pass through the polarizing plate 1b because it has been polarized by 90 degrees by the liquid crystal. When no electric field is applied, the light is not polarized, and therefore does not pass through the polarizing plate 1b, which has a different polarization axis. These two states make it possible to display characters or figures.

[Problems to be Solved by the Invention] However, these display devices have a viewing angle dependence due to the tilt of liquid crystal molecules, and have a drawback that the viewing angle is narrow. In particular, as liquid crystal display devices have recently become larger, a narrow viewing angle has resulted in the disadvantage that characters are difficult to read in the peripheral areas.

The present invention has been made to overcome the above-mentioned drawbacks, and an object of the present invention is to provide a liquid crystal display device with a wide viewing angle by providing a light scattering means on a polarizing plate to scatter polarized light. .

[Means and effects for solving the problems] The present invention has a structure in which a transparent plate having fine protrusions with a prismatic cross section is laminated on the polarizing plate 1b on the viewing side. The incident light that has passed through the plate 1b is repeatedly transmitted and reflected at the prism-shaped boundary surface, and then diverges.

[Example] FIG. 1 shows an example of a liquid crystal display device of the present invention.

In FIG. 1, the mat 4 has small prismatic protrusions 5.
A plurality of these are provided on the surface of the transparent plate. The light that has passed through the polarizing plate 1b is scattered by the matte surface that has been subjected to matte treatment.

FIG. 3 is an enlarged view of a part of the mat 4, showing one of the prism-shaped protrusions. When the incident light reaches the boundary point I of the prism, it is divided into light that is transmitted in the direction A and light that is reflected in the direction B. The light reflected in the direction of B is the boundary point of the prism ■
It is transmitted again in the direction of C and reflected in the direction of D. The light reflected in the direction of D is transmitted in the direction of E at the boundary point ■, and F
The light is divided into two parts: the light that is reflected in the direction of This reflected light is repeatedly reflected and transmitted at the boundary surface, and as a result, the light passing through the mat 4 is scattered in directions A, C, and E, making it possible to have a wide viewing angle. become able to.

In the above explanation, an example of application of the present invention to a transmissive liquid crystal display device was shown, but it can also be applied to a reflective liquid crystal display device by adding a matte-treated plate on top of the polarizing plate on the visible side. It is clear that similar effects can be achieved.

[Effects of the Invention] As described above, by applying matte processing or the like to the visible side of a liquid crystal display device and providing a means for scattering light, it is possible to greatly expand the viewing angle of a single display device, thereby providing an easy-to-read display. It becomes possible to provide the device at low cost.

[Brief explanation of drawings]

1 is a liquid crystal display device of the present invention, FIG. 2 is a conventional liquid crystal display device, and FIG. 3 is an enlarged view of a part of the mat 4 in FIG. 1. la, lb; polarizing plate, 2a, 2b; glass, 3; liquid crystal
, 14; matte, 5; prismatic projections. Fig. 1 Fig. 2 Mf) - Jinsabicho9

Claims (1)

[Claims] 1. A liquid crystal display device comprising a polarizing plate, glass, and a liquid crystal, characterized in that the visible side polarizing plate is provided with a light scattering means.