JPS6112270B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a color liquid crystal display device that includes a liquid crystal display body and has a large number of color display pixels arranged in units of display pixels of the three primary colors of red, blue, and green. The present invention relates to improvements in display quality when the display device is used for display on televisions, etc.

[Prior art]

Conventionally, color display devices using liquid crystals include:
A method using polarizing plate color filters of three primary colors has been proposed.

Figures 1a, b, and c show the mask shapes of each polarizing plate when a unit pixel is formed using the three primary colors of color polarizing plates of red, blue, and green in a conventional liquid crystal display. Each of a, b, and c in the same figure is
In the order of 1, 2, and 3, there is a red polarizing plate, a blue polarizing plate, and a green polarizing plate. That is, the shaded areas are red,
Colored in blue and green. However, this order may be changed. When these polarizing plates are stacked, a picture element unit as shown in FIG. 2 can be formed. 4 is red,
5 is a blue picture element, and 6 is a green picture element. These three picture elements form a dot display unit of one pixel. Corresponding to this, the liquid crystal driving electrodes of the liquid crystal panel are formed into electrodes such as 7 in the horizontal direction, as shown in FIG.
Electrodes like 8 are formed in the vertical direction, horizontal electrodes are formed on the lower surface of the upper glass, vertical electrodes are formed on the upper surface of the lower glass, and liquid crystal is sealed between them. The liquid crystal layer must then be oriented in this example for a field effect display. FIG. 4 is a cross-sectional view of the above panel, where 9 is a red color polarizing plate, 10 is a blue color polarizing plate, 11 is a green color polarizing plate, and 12 is a red color polarizing plate.
is the upper glass, 13 is the upper electrode, 14 is the liquid crystal layer, 1
5 is a lower electrode, 16 is a lower glass, and 17 is a first linear polarizing plate. In reflective panels, there is an additional reflector underneath. The horizontal and vertical electrodes are multiplex driven. Here, the liquid crystal layer 14 is of a 90° twist nematic type, and the color polarizing plates 9, 10, 11 and the linear polarizing plate 17 are paired in a crossed state. Therefore, when no voltage is applied to the liquid crystal layer 14, the portion of the liquid crystal display panel to which no voltage is applied becomes transparent. Furthermore, if a reflecting plate (not shown) is placed on the back surface of the linear polarizing plate 17, the light transmitted through the color polarizing plates 9, 10, 11, the liquid crystal layer 14, and the linear polarizing plate 17 will be reflected by the reflecting plate. It will be done. For example, when each picture element is driven based on a television signal, etc., in the case of red display, a voltage is applied to the segment corresponding to picture element 4 of the red polarizing plate and it appears red, but blue and green picture elements 5 and 6 Since no voltage is applied to these segments, these picture elements 5,
6 is transparent. Furthermore, when the reflecting plate is placed on the back surface of the linear polarizing plate 17, the reflected light of blue and green is reflected as is. Therefore, the three picture elements as a whole have a pale red color, and the overall impression of the display is bright. By the way, in general, television signals undergo signal processing such that the image becomes dark when there is no color signal. However, when a TV signal is applied to the structure of the conventional liquid crystal display panel, the image becomes transparent and displayed brightly when there is no color signal, so the brightness is opposite to that of the TV signal. There are problems.
For example, when no color signal is applied to any of the three picture elements 4, 5, and 6, black should be displayed, but conventional liquid crystal display panels have the disadvantage that they become transparent.

〔the purpose〕

The present invention overcomes the above problems, and
It is an object of the present invention to provide a color liquid crystal display device that can realize a color display corresponding to the brightness of a television image signal by adding an electrode for black display in addition to three picture elements.

〔Example〕

FIGS. 5a, b, c, and d are examples of masks of a color polarizing plate and a linear polarizing plate used in the color display device of the first embodiment of the present invention. Figures a, b, and c are red, blue, and green color polarizing plate mask patterns, respectively, and figure d is a mask pattern of the linear polarizing plate in Figure 2. That is, the shaded area 18 is a red polarizing plate mask,
19 is a blue polarizing plate mask, 20 is a green polarizing plate mask,
21 is a linear polarizing plate mask. These are arranged to form a picture element unit as shown in FIG. In other words, 22
is a red pixel, 23 is a blue pixel, 24 is a green pixel,
25 is a black picture element. Of course, in this case, an electrode for the black picture element must be provided in addition to the electrode structure shown in FIG. As a result, when no signal is received in any of the red, blue, or green pixels, voltage is applied to the 25 pixels corresponding to the linear polarizing plate to display black, and the 4 pixels Overall, a dark display can be achieved. In this way, four picture elements constitute a dot display unit of one image. Furthermore, this black picture element can essentially be used as a picture element for brightness modulation.

〔effect〕

As described above, the present invention has a liquid crystal sealed in a pair of substrates, a three-primary color polarizing plate consisting of three layers of red, blue, and green laminated on one of the pair of substrates, and a three-color polarizing plate of three primary colors laminated on one of the pair of substrates, and on the other substrate. In a color liquid crystal display device in which a first linearly polarizing plate is placed on the three primary color polarizing plates, three pixel patterns, which are color display units, are formed on each of the three primary color polarizing plates. A second linearly polarizing plate is mounted, a fourth pixel pattern is formed on the second linearly polarizing plate, and an electrode corresponding to each pixel pattern is provided on one of the pair of substrates. Because of this formation, color display corresponding to the brightness of the TV image signal is possible, and by driving the voltage applied to the electrode corresponding to the fourth picture element independently of the electrode of the third picture element, four pictures can be displayed. This has the effect that the brightness of the dot portion made of elements can be arbitrarily adjusted.

[Brief explanation of the drawing]

FIGS. 1A, 1B, and 1C are plan views showing mask patterns of a conventional color polarizing plate. FIG. 2 is a plan view showing a conventional dot display unit. FIG. 3 is a plan view showing the drive electrode structure of liquid crystal. FIG. 4 is a sectional view of a conventional color liquid crystal display device. Figure 5 a, b, c, d
FIG. 2 is a plan view showing a mask pattern of a polarizing plate of the present invention. FIG. 6 is a plan view showing the dot display unit of the present invention. 1, 4, 18...Red polarized mask pattern,
2, 5, 19... Blue polarized light mask pattern, 3,
6, 20... Green polarization mask pattern, 21...
Second linear polarizer mask pattern.

Claims (1)

[Claims] 1 A liquid crystal is sealed in a pair of substrates, a three-primary color polarizing plate consisting of three layers of red, blue, and green is laminated on one of the pair of substrates, and a first polarizing plate is placed on the other substrate.
In a color liquid crystal display device in which a linearly polarizing plate is mounted, a pixel pattern is formed on each of the three primary color polarizing plates, and a second linear polarizing plate is mounted on the three primary color polarizing plates, a fourth pixel pattern is formed on the second linearly polarizing plate, and the four pixel patterns constitute one dot display unit;
A color liquid crystal display device characterized in that electrodes corresponding to the respective picture element patterns are formed on one of the pair of substrates.