JPS5936281A - Liquid crystal display element - 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 The present invention relates to a display element using liquid crystal, and particularly aims to improve the contrast of a display element that performs negative display.

There are two types of display formats for display elements using liquid crystals: negative display, which allows light to pass through only the liquid crystal part to which a predetermined voltage is applied, and positive display, which allows light to pass through other parts except for the above part. The latter type of display is better in terms of visibility because it reduces the amount of light that enters the user's eyes, causing less fatigue for the user, and because the figure 1 stands out brightly on a dark background. ○ Figures 1 and 2 are diagrams showing the configuration of a display element that displays a conventional negative display. electrode 1,
A space is provided between the two transparent insulating substrates 3 and 4 forming the substrate 2 and the spacer 5, and a liquid crystal 6 is sealed in the space, and polarizing members 7 and 8 are provided on the outer surfaces of the substrates 3 and 4. ing.

The liquid crystal 6 used here is a field effect type P-type nematic liquid crystal to which cholesteric liquid crystal is added.
Due to the orientation treatment applied to the inner surfaces of the substrates 3 and 4, the substrates 3 and 4 are arranged in a twisted manner, and the twisted polarizing members 7 and 8 (-1) have their polarization axes aligned in the same direction.

Note that M is an observer.

By the way, liquid crystal display elements can be classified into transmissive type and reflective type depending on the lighting method, and the former type has a light source (
(not shown), and when the light from this light source passes through the polarizing member 8 on the rear side, it becomes polarized light with only a unidirectional component and passes through the liquid crystal 6. At this time, if a predetermined potential difference is generated between the electrodes 1 and 2, the liquid crystal 6 in this portion is aligned perpendicular to the electrodes 1 and 2, and the polarized light passes through the polarizing member 7 on the 11-year-old side.

In areas where a predetermined potential difference is not created between the electrodes 1 and 2 and where the electrodes 1 and 2 are not formed, the liquid crystal 6 is arranged in a twisted manner, so the polarized light is twisted by 90 degrees, and the polarization of this polarized light is The axial direction and the polarization axis direction of the front polarizing member 7 do not match, so the polarized light is absorbed. In other words, the part of the electrode 1°2 where there is a predetermined potential difference becomes a "picture" that shines brightly with the color of the light from the light source, and the other part becomes a dark "ground" where no light passes through, which allows the observer M to see a predetermined image. The display can be identified.

On the other hand, the latter has a light source (not shown) in front of the liquid crystal display element.
A reflecting member (not shown) is provided on the rear surface of the polarizing member 8 on the rear side. The light from the light source is transmitted through the polarizing member 7 on the front side.
When the light passes through the liquid crystal 6, the light becomes polarized with only one direction component. Here, as described above, only the polarized light that passes through the parts of the electric whips 1 and 2 where a predetermined potential difference occurs can pass through the polarizing member 8 on the rear side, and is reflected by the reflecting member and returned to the polarizing member 8. LCD 6
゜Since it passes through the polarizing member 7, it shines brightly with the color of the light source, and the polarized light that passes through other parts is polarized by the liquid crystal 6.
Because it is twisted so much that it cannot pass through the polarizing member on the rear side and is absorbed, the light does not pass through and becomes a dark field, which allows the observer M to identify the predetermined display.

By the way, in a liquid crystal display element having such a configuration, when the distance between the insulating substrates 1 and 2 is shortened to improve responsiveness, the twisting effect of the long wavelength component light is not sufficiently performed, and a predetermined potential difference is not generated. The difference in brightness from the part in the figure where light also passes through the area and a predetermined potential difference is created 1. In other words, there was a problem in that the contrast decreased and the image became distorted.

This invention was devised by focusing on these conventional problems, and includes a liquid crystal that has a complementary color relationship with the color of the light that displays the "ground" using a light source and color filter in the conventional liquid crystal. By adding a small amount of the same type of dichroic dye, it is intended to provide a liquid crystal display element with fast response and high contrast.

Hereinafter, an embodiment of the present invention will be described based on FIGS. 3 and 4. The same parts as in the conventional example shown in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

The liquid crystal 6 is a field effect type P-type nematic liquid crystal to which a trace amount of cholesteric liquid crystal is added, and a trace amount of a P-type dichroic dye 9 is also added.

This dichroic dye is a dye whose color is complementary to the display color, that is, the color of the light source or color filter that makes the part shown in Figure 1 where a predetermined potential difference occurs between electrodes 1 and 2 shine brightly. For example, in order to use this liquid crystal display element, a light source 10 is provided behind the rear polarizing member 8, and a red light source 10 is provided between the rear polarizing member 8 and the light source 10 in order to display the part shown in Figure 1 in red. A color filter 11 is provided. Note that this color filter 11 may be integrated with the polarizing member 8 on the rear side. Then, the dichroic dye 9 put into the liquid crystal 6
There are substances that color light blue, such as BDHC.
Chemicals Ltd product number DI6 is used.

According to such a configuration, when a predetermined potential difference is generated between the electrodes 1 and 2, the liquid crystal 6 in this part is aligned perpendicularly to the electrode 1.2, and the dichroic dye 9 also follows the liquid crystal 6. Since the light is arranged vertically, the light is not colored, and the red polarized light 1 passing through the rear polarizing member 8 passes through the front polarizing member 7 without being twisted or colored. On the other hand, in areas where a predetermined potential difference is not generated between the electrodes 1 and 2, or where the electrodes 1 and 2 are not formed, the liquid crystal 6 maintains a twisted alignment, and follows the liquid crystal 6 with the dichroic dye 9 twisted. 2
Because they are arranged in parallel, the light is colored, and the red polarized light that passes through the latter polarizing member 8 is polarized by the liquid crystal 6.
Since the polarization axis direction of this polarized light that is twisted by 0 degrees does not match the polarization axis direction of the front polarizing member 7, the polarized light is absorbed, and the red or long wavelength component polarization, which is less susceptible to the twisting effect in the liquid crystal 6, is Since the light is cut by the dichroic dye 9 that colors the light blue, that is, the dichroic dye 9 that does not pass long-wavelength component light, almost completely knee-polarized light is absorbed in this part, and the light from the light source 10 passes through. Therefore, only the parts of electrodes 1 and 2 where there is a predetermined potential difference glow in red.
The rest of the area becomes a dark "ground" where no light passes through,
This allows the observer M to identify the predetermined display.

For this reason, even if the distance between the insulating substrates 3 and 4 is shortened and the electrodes 1 and 2 are brought closer together in order to improve responsiveness, light with long wavelength components passes through, making it difficult to distinguish between "ground" and "figure". It is possible to solve the problem of a decrease in contrast when the image is difficult to attach.

Although the transmission type has been described, even a reflective type in which a reflective member is provided behind the color filter 11 and a light source 10 is placed in front of the front polarizing member 7, the same display operation can be performed as in the conventional example. It is clear from the explanation.

Further, in the above embodiment, the liquid crystal 6. Although P-type is used as the dichroic dye 9, it is not limited to this, and combinations with n-type nematic liquid crystals and n-type dichroic dyes may also be used. Selection of the polarization axis directions of the polarizing members 7 and 8 The same function as that described above can be performed.

However, the display color and the color colored by the dichroic dye 9 are limited to red and blue, respectively. If the partner colors are complementary to each other, the above purpose and effect will be satisfied. can do.

By adding a small amount of dichroic dye to the liquid crystal, which colors the light passing through the liquid crystal in the "ground" part of the hydrogen element in a complementary color to the color of the "figure", ” and “earth”
It is possible to increase the contrast between the two images and to obtain clear display operations.

In particular, in order to improve responsiveness, the distance between the electrodes is shortened, and it is possible to block the long wavelength component light that passes through the part shown in the figure where the passage of the original red light should be cut, improving responsiveness and contrast. This is an extremely practical effect in that it is possible to achieve effects that could not be achieved at the same time with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of main parts showing the structure of a conventional liquid crystal display element, FIG. 2 is a diagram for explaining the display operation of the same liquid crystal display element, and FIG. 3 is a liquid crystal display according to an embodiment of the present invention. FIG. 4 of the display element is a second view for explaining the display operation of the liquid crystal display element as described above. 1.2: Electrode 3, 4: Insulating substrate 5: Subazer 6: Liquid crystal 7.8: Polarizing member 9: Dichroic dye 10゛ light source
11. Color filter 1st agony ■t. Figure 2 M 598-

Claims (1)

[Claims] In a liquid crystal display element that performs a negative display operation with a negative display consisting of a "figure through which light passes" and a "ground" which does not allow light to pass through, the light passing through the liquid crystal in the "ground" portion is A liquid crystal display element characterized in that a trace amount of a dichroic dye that colors the liquid crystal in a complementary color to the color shown in FIG. 1 is added to the liquid crystal.