JPS62244018A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To execute a gradation display by only a voltage of two levels, by constituting one piece of picture element, of plural pieces of segments. CONSTITUTION:In a liquid crystal display element which has used a ferroelectric liquid crystal, one piece of picture element is constituted of plural pieces of segments. In this state, to each segment 41, a voltage of VON or VOFF is impressed and it is set to a state of turn-on or turn-off, and by a ratio of the number of pieces of segments being in the respective states, a half tone display is executed. The impressed voltage has only two levels of VON and VOFF, and also, one piece of picture element is divided in advance into plural pieces of segments, and each segment is controlled independently, therefore, an uneven display caused by ununiformity of a distribution of turn-on and turn-off areas can be eliminated.

Description

[Detailed description of the invention] [Fields of use of M Tojo] The present invention relates to a liquid crystal display element.

[Conventional technology]

In a display element using ferroelectric liquid crystal, the recirculating voltage t
Shi! By changing the area of the lit part and the non-lit part within one pixel, the floor 11=ff is displayed.

[Problem that the invention seeks to solve]

The entire display IJx weir of a display element used with ferroelectric liquid crystal is shown in FIG. 11 is represented on one pixel, 12 is a liquid crystal molecule,
13 is a polarizing plate direction, 14 is a lighting section, and 15 is a non-lighting section. The molecular orientation of the ferroelectric liquid crystal can take only two states as shown in the figure; in a very small area, it can only be in either the lit or non-lit state. However, if we look at a rather large area, as shown in Figure a1, two states, lighting and non-lighting hatched areas, are mixed, and the ratio of the area can be changed by changing the applied voltage. Therefore, even in a display element used on a ferroelectric liquid crystal, a vI4 display is possible.

The second factor shows the relationship between the average brightness of the pixel 'il& and the applied voltage. In this way, by applying a voltage between V and V, it is possible to display all halftones, but generally this threshold characteristic is very steep, and for example, V, = I QV
, V, =11.5'V, etc. There, on the 16th floor wI
4 display-r, the voltage must be changed at intervals of tα1v, which is not an easy method considering the non-uniformity of the liquid crystal layer thickness. Furthermore, the distribution of lit areas and non-lit areas is non-uniform. In other words, after all pixels are first turned on, the voltage at all pixels (V+ <v<vt) k
Even if the voltage is applied, the distribution of non-lighted areas is not uniform, so 94
As shown in FIG. 5, a certain lff1i pixel may be in an intermediate state, and another pixel may be in a completely non-lit state.

Therefore, it is difficult to display the intermediate 8J4 using a ferroelectric liquid crystal display element using the conventional method.

It is an object of the present invention to solve all of these problems and to realize a large flat display capable of displaying halftones.

[Means for resolving the gap]

In the present invention, one pixel is entirely composed of a plurality of segments, so that each segment has a VoN (〉■
, ) Father is vopy ((71) Apply voltage to set the state to either lighting or non-lighting, and set the intermediate a according to the ratio of the number of segments in each state.
It is characterized by being carried out in '4 display.

That is, the applied voltage has two levels of VOR and vOF'l (
7) In addition, one pixel is divided into multiple segments in advance, and each segment is controlled independently, so there is no display unevenness due to uneven distribution of lighting and non-lighting areas. can do.

[Actual example]

The fourth screen shows a pixel portion of the liquid crystal display element according to the present invention. 4
1 represents one entire segment, surrounded by a dotted line and 7? : The part is one pixel. In this figure, one pixel is divided into 79 segments. As a precaution, it is displayed in 10 gradations. Here, if one segment is regarded as one pixel on the entire surface, the duty ratio becomes five times. However, in the case of a ferroelectric liquid crystal, the contrast ratio is unrelated to the duty ratio, and the contrast ratio does not decrease due to the entire duty ratio being violated. Please forgive μ5ec-several tens of μs
Since it responds at a high speed of ec, even if the number of scanning lines increases, the writing time for one screen is sufficiently fast.

As the first dark example, number of pixels is 200x200, 1 pixel is 3x
It was created on the display element as 3 segments. The writing time for one screen was 60 m5ec, and 10 gradations could be displayed.

In the second embodiment, the number of pixels is 4θ0×640, 1 pixel is 3×5
As a segment, 1 screen -t1 key included time 96m5
EC Natsu9 is capable of displaying 16 gradations.

In the third embodiment, the number of pixels is 200×200, and each pixel is 4×5.
Writing time for one screen as a segment: 64 m5e
c 15 gradation display is now possible.

〔Effect of the invention〕

By dividing one pixel into multiple segments, it is now possible to control the distribution of lit and non-lit areas, making it possible to reliably display gradations using only two levels of voltage. . The present invention is based on floor IJ! It can be applied to flat displays that require 4 displays.

[Brief explanation of drawings]

Figure 1 is a diagram showing the display principle of a display element using a strong FIj'6 liquid crystal, Figure 2 is a diagram showing the relationship between brightness and applied voltage, and Figure 3 is the distribution of lighting and non-lighting areas. Figure 4 showing
The figure is a diagram showing pixels of a display element according to the present invention. 11, pixel 12, quasi-crystal molecule 15, polarization direction of polarizing plate 14, lighting section 11, non-lighting section 41, segment. Cell 1(v) Section 2, Figure 4

Claims (2)

[Claims] (1) A liquid crystal display element using ferroelectric liquid crystal, characterized in that one pixel is constituted by a plurality of segments. (2) A liquid crystal display element according to claim 1, wherein the light transmission intensity of the plurality of segments is controlled independently of each other by voltage.