JPS60222824A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To decrease a dark level and to obtain high display contrast by varying the polarizing directons of the polarizing plates disposed to the display pattern part provided on the respective same plane of upper and lower substrates according to the wavelength of incident light. CONSTITUTION:The oriented films of the respective display pattern parts provided on the upper and lower substrates 2, 3 consisting of display patterns for a red part 1a, a green part 1b and a blue part 1c are rubbed in arrow I, K directions by which a liquid crystal orientation is executed. Such substrates 2, 3 are adhered to each other by a sealing resin and are thermally cured and thereafter a liquid crystal is sealed therein to manufacture a liquid crystal display panel 1. color filters 4 provided respectively with red 4a, green 4b and blue 4c in the positions corresponding to the respective display patterns are disposed on top and bottom of the panel 1 an the polarizing plates 5, 6 having polarizing directions in the arrow directions A, B, directions C, D and directions E, F are adhered onto the respective filters 4. The directions A-F are therefore so disposed that the optical paths after incidence of light on the liquid crystal layer until transmission under refraction are short and that the intersecting angles of the display patterns of the plates 5, 6 in the polarizing directions are made smaller in order of red, green and blue.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a liquid crystal display device that can be used for color display with high display contrast.

Conventional configurations and their problems In recent years, the electro-optical effect of liquid crystals has been utilized in display devices to display various types of displays, such as displaying 9 numerical characters and 9 images. There is. Additionally, there is an increasing demand for display colors to change from monochrome to full color.

Conventionally, full-color liquid, high-display panels have three-color filters, such as red, blue, and green, installed on the top or inside the panel, each at a position corresponding to the liquid crystal display electrode pattern. This can be achieved by controlling the voltage applied to each display electrode.・However, the contrast of full color display is still low, especially in red,
The problem remains that appropriate display colors cannot be obtained due to differences in display contrast between blue and green wavelength light. This is because there is leakage light when the liquid crystal display panel shuts off light, which reduces the overall display contrast, and furthermore, because the leakage light differs depending on the incident wavelength, appropriate display colors cannot be obtained.

Figure 1 explains the above phenomenon and shows that the leakage light transmittance when light is blocked (hereinafter referred to as dark level) depends on the panel gap for each of the three incident wavelengths: red, blue, and green. FIG. 1 is a diagram illustrating a twisted nematic liquid crystal display panel. Therefore, in order to obtain a liquid crystal panel with a high contrast for each incident wavelength of light using a panel with the same gap, a method is required to reduce the dark level, which is the standard for display contrast, in accordance with the wavelength of the incident light. There is.

Purpose of the Invention The present invention has been made in view of these conventional problems, and provides a liquid crystal display that can obtain high display contrast by reducing the dark level of light incident on the liquid crystal display panel. The aim is to provide equipment.

Structure of the Invention In order to achieve this object, the liquid crystal display device of the present invention includes all polarizing plates disposed in the display pattern portions provided on the same plane of the upper and lower substrates, and whose polarization direction is adjusted according to the wavelength of incident light. This is done in a different direction, and by reducing the dark level, high display contrast can be obtained.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will now be described with reference to the drawings.

FIG. 2 shows a configuration diagram of a liquid crystal display device according to an embodiment of the present invention. First, the red part 1N.

Upper and lower 2 consisting of a display pattern of green part 1b and blue part 1C
Liquid crystal alignment is performed by rubbing the alignment film of each display pattern portion provided on the substrate 2.3 in the direction of arrow I.

The two substrates 2 and 3 thus obtained are bonded together with a sealing resin and cured by heat, and then twisted nematic liquid crystal is encapsulated to produce the liquid crystal display panel 1 shown in FIG. 2.

Next, color filters 4 provided with red 4a, green 4b, and blue 4C are placed above and below the liquid crystal display panel 1 at positions corresponding to each of the above display patterns, and are arranged in the directions of arrows A, B, C, and D. , a polarizing plate 5 having polarization directions in the E and F directions,
Paste 6 onto the upper and lower color filters 4, respectively. In this way, the liquid crystal display device of the present invention is manufactured.

By the way, in the polarization direction A-F of the two upper and lower polarizing plates 6° 6 in each display pattern, light has a short path from entering the liquid crystal layer to passing through while being refracted, that is, light with a short wavelength. In contrast, as shown in FIG. 3, the polarization crossing angle r of the polarization directions G and H on the display pattern of the upper and lower polarizing plates 5.6 is smaller than that of other long wavelength light, that is, red, green,
They are arranged so that the polarization crossing angle r becomes smaller in the order of blue.

Here, the transmission path of light in the liquid crystal crosses the liquid crystal alignment.

Although the case of following the direction of the angle α has been shown, when following the orientation crossing angle β, the polarization direction may be set and arranged so that the transmission path of the short wavelength light is shortened based on the same concept. Here, in FIG. 2, the polarization direction arrows B, D, and F on the display pattern of the lower polarizing plate 6 are the same.

Polarization direction arrows A, C, Ii:f on the display pattern of the upper polarizing plate 6: In the above description, the configuration is explained in which the directions are different depending on the wavelength of the incident light. ,C, ]i:f, (It is possible to set the polarization direction to be the same and to set the arrows B, D, and F to different polarization directions on the lower polarizing plate 6. Furthermore, the upper and lower polarizing plates 6 and 6 can be used to The polarization direction may be the same, and the polarization directions may be different between display patterns.Also, in the above embodiment, the case where there are three display patterns provided in the same plane is explained, but when the number of display patterns is two. It is also effective in cases where there are more than one or four or more.

By the way, the polarizing plates 5 and 6 have different display colors for each display pattern and must have corresponding polarization direction arrows A to F, so they cannot be formed with a single polarizing plate that polarizes light in only a single direction. . Therefore, in the present invention, a polarizing plate having anisotropic polarization is combined with the liquid crystal display panel 1 in the following manner.

According to FIG. 4, this anisotropic polarizing plate is attached to the liquid crystal display panel 1.
We will explain how to manufacture a liquid crystal display device in combination with the following.

First, as shown in FIG. 4, three polarizing plates, 8°9, are placed at two locations each with windows 7a, 7b, 8a, and 8b.

Punch out the desired pattern with a press so that it has 9a and 9b. Here, the polarizing plate has a polarization direction in the direction of the arrow corresponding to the polarization direction of the red color display pattern 1a, and the green color display pattern 1b.

Son a is located at the location corresponding to the blue section display pattern 1C.

7b is formed. Similarly, the polarizing plates 8 and 9 have polarization directions G and G adapted to each display color, and windows 8fL are provided at positions corresponding to display patterns other than necessary display patterns.

8b, 9a, '9b are formed. The necessary anisotropic polarizing plate is created by overlapping these three polarizing plates 7, 8.9. FIG. 2 shows a state in which all two such anisotropic polarizing plates -F are arranged under the liquid crystal display panel 1, and a liquid crystal display device is manufactured by pasting them together.

In this example, the formation of polarizing plates having three types of anisotropically polarized light has been described. However, by processing and overlapping the number of polarizing plates according to the types of anisotropically polarized light using the above-mentioned press, it is possible to obtain the desired polarized light. A directional polarizing plate can be formed.

In this way, the color liquid crystal display device of the present invention with high display contrast can be obtained.

Here, the location of the color filter and polarizing plate is
It is not limited to this embodiment, and either may be the upper or lower side. However, the color filter may be provided inside the liquid crystal display panel, and furthermore, a polarizing plate having a color filter function may be used.

Effects of the Invention According to the present invention, an anisotropic polarizing plate corresponding to each display pattern can be easily produced using a press punching process. A liquid crystal display device having a color display with high display contrast can be easily and inexpensively manufactured and provided by simply arranging a directional light distribution plate on a liquid crystal display panel.

[Brief explanation of the drawing]

Figure 1 illustrates the present invention, and shows that the leakage light transmittance when blocking light depends on the panel gear and knob depending on the incident wavelength. Figure 2 illustrates a twisted nematic liquid crystal display panel. FIG. 3 is an exploded perspective view showing an embodiment of the liquid crystal display device of the present invention, in which polarizing plates and color filters having anisotropic polarization in different directions are arranged on three display patterns provided in the same plane. 4 is a diagram showing the polarization angle of a polarizing plate placed on a liquid crystal display pattern which is not used to explain the present invention, and FIG. FIG. 2 is an exploded perspective view showing a liquid crystal display device according to the present invention. 1...Liquid crystal display panel, 1a, 1b, 10...
...display pattern (red section, green section, blue section),
2... Upper board, 3... Lower board, 4...
...Color filter, 4a, 4b, 4C...
Red, green, blue parts, 5゜6, 7, 8, 9-...
Polarizing plates, 7a, 7b, 8a. 8b, 91L, 9b...window. Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure half diameter, soft (μm) Figure 3 ■ Figure 4

Claims (1)

[Claims] 1. A liquid crystal display device characterized in that polarizing plates are disposed in the display/display pattern portions provided on the same plane of the upper and lower substrates, and the polarization directions of the plates are set in different directions depending on the wavelength of incident light.