JPH0215076B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves interposing a liquid crystal composition between opposing electrodes and applying a voltage between the electrodes to control the optical rotation, absorbance, etc. of the liquid crystal layer, and to The present invention relates to a liquid crystal display that displays images. More specifically, the present invention relates to the shape of the display electrode of such a display body.

Liquid crystal displays take advantage of their characteristics of low power and low voltage drive, and are used in the displays of electronic devices such as digital watches and calculators. Conventionally, a twisted nematic (TN) method has been used, in which polarizing plates are placed on both sides of the liquid crystal layer with their polarization axes crossing, and the liquid crystal molecules are interposed between two support plates in a 90° twisted state. However, guest-host methods using dichroic dyes that produce different colors depending on the orientation direction are also being used.

As the range of applications expands, larger display capacities are required, and the display method is a time-sharing method in which electrodes are formed in a matrix, and display is performed based on the difference in the effective value of the voltage applied to selected pixels and non-selected pixels. Drive has become essential.

Figure 1 shows the voltage-transmittance characteristics of a liquid crystal cell using the TN method. The horizontal axis shows the effective voltage value V, and the vertical axis shows the relative light transmittance T (%). With the increase in the number of divided lines in time-division driving, the selection point effective voltage Vs,
The ratio α = Vs / Vu of the effective voltage Vu at the non-selected point is small, and a steep VT characteristic is required, but due to the limitations of liquid crystals, in reality the transmittance Ts at the selected point is quite high. I have no choice but to use it. Figure 2 shows Vth
The orientation state of liquid crystal molecules in a TN cell to which the above effective voltage is applied is shown. The surfaces of opposing glass substrates 3 having SnO ₂ transparent electrodes 1 and 2 are rubbed in the direction of arrow 5, and the surface of 4 is rubbed in the front direction. The liquid crystal molecules 6 and 7 near the surface are oriented with a slight inclination in the horizontal direction, but the liquid crystal molecules 8 and 9 gradually rise toward the center. When the effective value of the voltage is high, as shown in Figure 3, the liquid crystal molecules 12 and 13 are aligned almost vertically, and the contrast with the surroundings is highest when viewed from the front, but when the voltage is low, The viewing direction 10 is at a fairly low angle from vertical, requiring the display to be used at an angle. Furthermore, the reality is that this tendency increases as the number of lines to be driven increases.

Generally, when viewing a flat display at an angle, the image is deformed and flattened due to perspective, making thin objects such as Chinese characters extremely difficult to see. In order to solve this problem, the present invention deforms the shape of the display electrode so that it becomes larger from the front to the other side when viewed from the clear viewing direction so that the displayed image can be seen normally in the tilted state. It has characteristics in points. The present invention will be explained below with reference to Examples.

FIGS. 4a and 4b are a front view and an inclined view when the number 2 is displayed by matrix electrodes of equal size. When a display like that shown in a is tilted, pixels further away become smaller due to deformation caused by perspective.

Figures 5a and 5b show the case with a modified matrix electrode according to the invention. By making the pixels thicker and larger toward the back, when the pixels are tilted, the distortion is compensated for as shown in Figure b, giving the illusion that the pixels are viewed from the front. Such an effect is achieved not only in matrix-like electrodes but also in segment-like electrodes.
FIG. 6 shows an example of seven segments according to the present invention. Naturally, the counter electrode side must be similarly distorted.

Such an effect can be applied not only to time-division driving but also to liquid crystal displays for low voltage driving such as 1.5V driving. Further, in this embodiment, only the TN method has been described, but any display that utilizes alignment control of liquid crystal molecules can be used, and is effective in a guest-host method, a phase transition method, etc.

As is clear from the above examples, higher density and lower voltage are clear directions that liquid crystal displays will follow in the future, and the effects of the present invention are significant.
This promotes the use of liquid crystal displays in everything from solar battery-equipped calculators to handheld computer displays and terminals.

As described above, according to the present invention, when the electrodes are viewed in the bright viewing direction defined by the tilt angle of the liquid crystal molecules in the liquid crystal layer, the widths of the electrodes are approximately equal. Since the width is formed to gradually increase from the clear viewing direction toward the opposite direction, the sense of perspective in the display that occurs when the liquid crystal display is viewed with the liquid crystal display tilted is corrected. Therefore, it has the unique effect of providing substantially the same display as when viewing the liquid crystal display from the front.

[Brief explanation of drawings]

Figure 1 shows the voltage-transmittance characteristics of the TN method. FIG. 2 is a diagram showing the alignment state of liquid crystal molecules when a voltage slightly higher than Vth is applied. 1, 2... Transparent electrode, 3, 4... Glass support, 5
...Rubbing direction, 6,7...Liquid crystal molecules on the surface,8,
9...Liquid crystal molecules in the inner layer, 10...Visual viewing direction, 11,
12...Polarizing plate. FIG. 3 is a diagram showing the alignment state of liquid crystal molecules when a sufficiently high voltage is applied. 12,13...Liquid crystal molecules. FIG. 4a is a front view of a normal matrix display. 15...Signal electrode, 16...Scanning electrode. FIG. 4b is a tilted view of a normal matrix display. FIG. 5a is a diagram showing a matrix display distorted based on perspective. Figure 5b is the fifth
It is a figure seen at an angle. FIG. 6 is a front view of the electrode when the perspective method is used in the segment method. 17... Segment part, 18... Lead part.

Claims (1)

[Claims] 1. In a liquid crystal display in which a liquid crystal layer is sandwiched between a pair of substrates having electrodes on opposing inner surfaces, when viewed in a clear viewing direction defined by the tilt angle of liquid crystal molecules in the liquid crystal layer, the electrodes A liquid crystal display, characterized in that the width of the electrode is formed so that it gradually becomes wider from the clear viewing direction side toward the opposite direction so that the widths of the electrodes are visually recognized to be approximately equal.