JPS60136716A - Liquid-crystal display device - Google Patents

Abstract

PURPOSE:To observe respective display parts with good contrast and an excellent background color while making the direction of vision coincident to the direction of clear vision by orienting liquid crystal cells of a liquid crystal display panel which is divided into plural pieces in different specific directions. CONSTITUTION:A liquid crystal cell 6 is divided into two right and left parts 6A and 6B and a wide-range indication display is made. The directions of liquid crystal orientation of those parts 6A and 6B are made 90 deg. different by a mask clapping method, etc., to make the direction of vision coincident with the direction of clear vision. Consequently, the wide-range liquid crystal display is observed with good contrast and an excellent background color.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal display device that is subjected to alignment treatment so as to have a plurality of different clear viewing directions.

Normally, a twisted nematic type liquid crystal display panel in a liquid crystal display device consists of two substrates with electrodes that are horizontally aligned so that the alignment directions of liquid crystal molecules intersect with each other at approximately 90 degrees. It has a sandwich structure with liquid crystal placed in between and filled with liquid crystal. Specifically, as shown in Fig. 1, one electrode made of a transparent conductive material is provided so as to have a shape corresponding to the symbols such as characters and scales to be displayed, and then a polyimide resin, polyamide resin, etc. is coated on the surface of this electrode 1A. An electrode 1B made of a transparent conductive material or a reflective metal conductive material is provided opposite to the substrate 3A made of a transparent insulating flat plate made of glass, plastic, etc., and provided with an overcoat material 2A made of the above as required. After that, a substrate 3B similar to the substrate 3A is provided with an overcoat side slope 2B similar to the overcoat strip 2A as required,
Between a seal fA4 made of epoxy resin, polyamide resin, etc., which seals the periphery of the substrates 3A and 3B, which are located facing each other with a slight /h interval so that the electrodes 1A and IB face each other, and the substrates 3A and 3]3. A liquid crystal cell 6 is configured with the liquid crystal 5 sealed in the substrate 3A as required.

A liquid crystal display panel (hereinafter referred to as a panel) 8 is constructed by disposing polarizing plates 7A and 7B on both outer surfaces of 3B.

(7), J: The liquid crystal 5 of the twisted nematic panel 8 has a positive dielectric anisotropy, and the distribution of the center of gravity of the molecules is spatially random, but the long axes are aligned in one direction. Substrates 3A and 3B are formed by alignment treatment on the inner surfaces of 3A and 3B.
A P-type nematic liquid crystal is used in which the axial direction is twisted by 90 degrees while passing from one substrate 3A to the other substrate 3B, and the polarization axes of the polarizing plates 7A and 7B, which determine the polarized light to be transmitted, are orthogonal to each other. For example, when a voltage of a predetermined level or higher is not generated between the negative electrodes 1A and IB, the liquid crystal 5 maintains its initial molecular alignment and becomes polarized light with a unidirectional component by the rear polarizing plate 7B. When the light passes through the liquid crystal 5, the polarization axis is twisted by 90 degrees and reaches the front polarizing plate 7A, so that the polarization axis of the polarized light matches the direction of the polarization axis of the polarizing plate 7A, and the light can be transmitted. The display enters a non-display state where the entire screen appears bright.

Further, when a voltage of the predetermined level or more is generated between the predetermined polymerized portions of the electrodes 1A and IB, only the long axis of the molecules of the liquid crystal 5 between the electrodes 1A and IB portions where the voltage is generated is the substrate 3A,
Only in the portion of the liquid crystal 5 where the molecular arrangement has changed and is aligned perpendicularly to the plane 3B, the polarization axis is not twisted when the light is polarized in one direction by the rear polarizing plate 7B and transmitted through the liquid crystal 5. In order to reach the front polarizing plate 7A, the polarization axis of the polarized light and the polarizing plate 7A
Since the direction of the polarization axis is perpendicular to the direction of the polarization axis and no light can pass through, a dark ``figure'' appears on a bright ``ground J'' and a predetermined symbol is displayed in a positive manner. In the above description, it was assumed that light traveling from the rear of the panel 8 is used, that is, it is used as a transmission type. △ Even if traveling light is used, that is, it is used as a reflective type, the principle is the same, and furthermore, if the polarization axes of both polarizing plates 7A and 7B are arranged in a parallel relationship, dark "ground" ”, a bright “figure” appears and the predetermined symbol is displayed in a negative manner. In addition, as the liquid crystal 5, in addition to a nematic liquid crystal having positive dielectric anisotropy, a cholesteric liquid crystal, an optically active substance, a dichroic dye, etc. may be added as necessary, and a dichroic dye may be used. In the case of the so-called guest-host type in which the polarizing plates 7A and 7B are added, the polarizing plates 7A and 7B can be omitted, and an undercoat of SiO, AL"04, etc. is provided between the electrodes 1A and IB and the substrates 3A and 3B. Alternatively, a color polarizing plate can be used as the color filter or the polarizing plates 6A and 6B, or a light source can be provided at the rear by using a semi-transmissive reflective plate.Such a panel 8 can be used in the direction in which the liquid crystal molecules are aligned. This determines the direction in which the display can be seen clearly and the Kyo field angle is the widest, that is, the clear viewing direction, and this clear viewing direction is usually used to almost match the direction that the observer sees, that is, the visual viewing direction. The relationship between the direction and the alignment direction of liquid crystal molecules is specifically shown in Fig. 2. In the figure, the alignment direction of the liquid crystal molecules on the front substrate 3A is indicated by a solid line, and the alignment direction of the liquid crystal molecules on the rear substrate 3B is indicated by a broken line. By combining these orientation directions, the clear viewing direction can be expressed as 6:00 (front), 7:30C (left front), 4:30 (right front) 09, etc. using the direction indicated by the clock. In other words, depending on the combination of orientation directions of liquid crystal molecules, the clear viewing direction from the 6:00, 7:30, 4:30... direction provides the most cost-effective viewing and the widest viewing angle. Therefore, in the past, one panel 8 was formed by selecting only one clear viewing direction that coincided with the visual viewing direction of the observer, and aligning the liquid crystal molecules accordingly. In the case of a small size, the viewing direction of the panel 8 of the observer did not change much and almost coincided with one selected clear viewing direction 11.

However, the various instruments installed in commercial vehicles, automobiles, motorcycles, ships, etc., have become larger with digitalization, that is, they are becoming more widespread. However, panel 8
If it becomes a wide-range indicator type, the viewing direction from the observer's eyes to the panel 8 becomes wider, and the viewing angle becomes different between the center and both ends. For this reason, even if the panel 8 becomes a wide-range indication type, if one clear viewing direction shown in FIG. 2 is selected and a single panel 8 is oriented accordingly, for example, in FIG. As shown, the viewing direction of the viewer toward both left and right end sides of the panel 8 is completely different from the viewing direction 1j of the central portion. The contrast of panel 8 decreases when viewed from a direction slightly deviated from the clear viewing direction, and the background color is different, making the visibility significantly different between the viewing direction and other directions. This becomes noticeable when there is a high degree of angular dependence. As a result, it is difficult for the observer to see the vehicle, making it easy for the observer to feel fatigued, which may impede safe driving, especially while driving. For this reason, it has been difficult to make the panel 8 too large, that is, to have a wide range of indications.

The present invention has been made based on the above-mentioned circumstances, and provides a liquid crystal display device that allows an observer to view the display of each part with good contrast and background color even if the liquid crystal display panel is made into a wide-range display type. The purpose is to

In a liquid crystal display device having a liquid crystal display panel formed by two horizontally aligned substrates with electrodes arranged so that the electrode surfaces face each other, the liquid crystal display panel is divided into at least two parts. At the same time, different orientation treatments are performed, each having a clear viewing direction corresponding to the visual viewing direction of the observer. (The following description will be made with reference to FIGS. 4 and 5, but portions that are the same or similar to the conventional structure will be designated by the same reference numerals, and detailed explanation thereof will be omitted.

FIG. 4(5) shows a liquid crystal display panel 8 according to the present invention, and when it is divided into two left and right parts 8A, 8B, the viewing direction from the observer is approximately 4:30. ．． 9B
It will be almost 7:30.

Therefore, in order to match this visual direction, the
As shown in , the clear viewing direction of the left portion 6A of the liquid crystal cell 6 is
: 30. On the other hand, the clear viewing direction of the right portion 6B of the liquid crystal cell 6 is set to 7.
: The liquid crystal molecules are aligned in the respective alignment directions of 30.

To divide this one liquid crystal cell 6 into two or more parts and perform different alignment treatments, for example, as shown in FIG. 5, the divided parts of the substrate 3A (3B) are alternately covered with masks 9. This can be achieved by the horse scrubbing method, which performs orientation treatment.

In addition to dividing a single liquid crystal cell and performing different alignment treatments on each as described above, it is also possible to divide multiple liquid crystal cells that have been subjected to different alignment treatments so that their clear viewing direction and the viewer's viewing direction match. A combination of C is also possible.

Next, the operation of the present invention with the above configuration will be described.

The panel 8 is divided into two parts 8A and 8B according to the viewer's visual direction of 4:30 and 7°30, and the direction of the liquid crystal molecules of the divided liquid crystal cells 6A and 6B is set to 4:30 and 7°30, respectively, so that the clear viewing direction is 4:30.
30, 7:30 by alignment processing. As a result, the viewing direction and the bright viewing direction are almost the same, and the viewer can always view the liquid crystal display in the appropriate bright viewing direction, so that any part of the panel 8 can be viewed with almost the same contrast and background color. becomes possible. For this reason, even if the user looks at the panel 8 for a long time, there are fewer drawbacks such as the display being difficult to see in parts, and fatigue caused by the difficulty in viewing is also reduced.

In this embodiment, the liquid crystal cell 6 is divided into two parts, but it is not limited to this and can be divided into two or more parts.For example, the panel 8 can be divided into three parts on the left center right. It is also possible to have a combination of panels 8 having clear viewing directions of 4:30, 6:oo and 7:30, respectively. Therefore, even if the panel 8 is made into a wider area indicator type, better display can be achieved by dividing it into a plurality of parts and making the clear viewing direction and the viewer's viewing direction coincide with each other.

Further, it is most preferable to use a liquid crystal display device that is aligned so that the alignment directions of liquid crystal molecules intersect with each other at an angle of approximately 90 degrees, but this crossing angle is between 70 degrees and 11 degrees.
It can be used if it is about 0°, preferably 800 to 100
°. This depends on the arrangement of the polarization axis of the polarizing film, but
This is because if the intersection angle of the orientation directions of liquid crystal molecules deviates too much from 90°, the liquid crystal display device will appear colored red or green, and crosstalk will likely occur.

As described in detail above, according to the present invention, even if a liquid crystal display device is made into a wide-range display type, it can be divided into at least two parts, each having a clear viewing direction according to the viewer's viewing direction. By creating a liquid crystal display panel made of a combination of different alignment treatments, it is possible to provide a liquid crystal display device that allows an observer to view the entire liquid crystal display panel in a good color.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing a general liquid crystal display panel, Figure 2 is an explanatory diagram showing the relationship between the alignment direction of liquid crystal molecules and the viewing direction, and Figure 3 is a diagram showing the viewing direction for a wide-range indication type LCD panel. FIG. 4(a) 1 is a plan view showing the clear viewing direction of the liquid crystal display panel, FIG. 0 is a plan view showing the alignment process of the liquid crystal cell, and FIG. FIG. 3A, 3B...Substrate 6...Liquid crystal cell 8...Liquid crystal display channel Patent applicant Nippon Seiki Co., Ltd.

Claims (1)

[Claims] A twisted nematic type liquid crystal display consisting of two substrates with electrodes that are horizontally aligned so that one direction of alignment of liquid crystal molecules intersects each other at an angle of about 90 degrees, and arranged so that the electrode surfaces face each other. In the liquid crystal display device having a channel, the liquid crystal display panel is divided into at least two parts, each of which is subjected to different alignment treatments each having a clear viewing direction depending on a viewing direction of an observer. Display device.