JPS62208025A - Active matrix type liquid crystal display device - Google Patents

Abstract

PURPOSE:To attain character display with good color balance by providing at least three display electrodes for red, blue, and green without including an address line and a data line is a unit display dot. CONSTITUTION:Address lines G(Gi-1, Gi, Gi+1...) and data lines D(Di-1, Di, Di+1...) cross each other; and the line Gi is connected to the gates of plural TFTs in a column (i) and the line Di is connected to the drains of plural TFTs in a row (i). Then R, G, and B are display electrodes and connected to the sources of independent TFTs. Those display electrodes are arranged to equal area and form display dots P(Pi,i, Pi, Pi+2...), lines G and D are present in none of the dots P, and two lines G and D each are arranged between dots P. This constitution enables a color character display with good color balance without decreasing spatial resolution nor the amount of information.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an active matrix liquid crystal display device for color display.

(Prior Art) In recent years, a method of constructing a thin display device using a thin film transistor matrix has attracted attention.

This method uses WjI! Image information is stored in each dot of the transistor matrix, and this image information is transferred to a liquid crystal layer provided on the matrix substrate,
The purpose is to display a screen at a position corresponding to each dot on the L layer or the EC layer. This makes it possible to realize a display device that is in principle much thinner than those using CRTs, which have been the mainstream of conventional display devices. Also C
Since the RT surface water device collides high-energy electrons with a fluorescent substance, the emission time is on the order of milliseconds, and since the entire screen is not displayed, there is flicker noise, etc., which limits visibility. was there. On the other hand, a display device using a transistor matrix displays almost the entire time, and can provide a more natural screen than a CRT. Furthermore,
It has the advantages of being able to obtain a flat screen, and because it does not require a vacuum area, it can be made smaller and lighter.

FIG. 6 shows the basic configuration of a transistor matrix array, ie, an active matrix substrate.

The display screen is divided into a matrix of m lines vertically and n lines horizontally.
It is divided into m-n display pixels in total.

Memory circuits C11, C12, . . . , Cij, .
・.

Cmn is formed, and image information of each pixel is stored here. According to this image information, display is performed in a region corresponding to each pixel of the liquid crystal layer formed on the active matrix substrate.

A specific memory circuit having a simple configuration as shown in FIG. 7 is used. This is because in order to obtain a high-definition display screen, the matrix size m·n becomes large, and in order to produce a matrix circuit with a high yield, a simpler circuit is desired. In FIG. 7, Tij is a switching transistor, LC is a liquid crystal layer, and O8
is the capacity for storing image signals. Transistor T1j
The gate of is connected to the first address line xi, and the source is connected to the third data IYj. The address lines and data lines have V(Xi) and V
A signal voltage of (Yj) is supplied. When a signal to turn on the transistor is input to the address line xi, this transistor becomes conductive and the image signal prepared as the data IYj is stored in the memory JiCs. The liquid crystal layer LC is driven in accordance with this accumulated image signal. In addition, address IXi
The upper transistor Ti1. Ti2. ... are all turned on at the same time, and the image signals prepared for the data lines Yi, ``y'2, ... at that time are transmitted to each pixel memory circuit Ci1, Ci2, ... through the respective transistors.・
will be written to.

FIG. 8 shows pixels Cij, Ci+1. 3 schematically shows the timing at which an image signal is written at j. In the image signals φij, φi+1, and j in FIG. 8, the solid lines indicate the ideal timing of operation. That is, the image signal of pixel C1j starts to be captured at time ti1, and writing ends at ti1+Δt, and at the same time, the gate front pressure V(Xi) becomes zero, and then the next image signal is transferred to pixel Cij again at time ti2. Until written, φi
j will be held at its voltage level.

The above is the operating principle of the flat display device using the active matrix substrate shown in FIG.

By the way, in such a display device, the transistor material is S in a single crystal, polycrystal or amorphous state.
Polycrystalline materials such as i, CdSe, Te, and CdS are used. Particularly in recent years, polycrystalline semiconductor materials and amorphous 5i (a-8i
) is attracting attention.

Color display is possible in such an active matrix liquid crystal display device. Red (R) is placed on the counter electrode substrate facing the active matrix substrate with the liquid crystal layer in between.
Color display can be easily performed by providing green (G) and blue (B) color filters and aligning these filters with each pixel of the active matrix substrate. The arrangement of the color filters includes a stripe-like arrangement as shown in FIG. 9(a), a mosaic-like arrangement as shown in FIG. 9(b), and the like. In order to increase the spatial resolution, R,
It is desirable to substantially reduce the color arrangement interval a of each pixel of G and B, and in this sense, it is better to make the color arrangement interval a of each pixel of G and B smaller than that of FIG. 9(a).
b) is better.

However, if we consider the case where characters are displayed in the arrangement shown in Figure 9(b), the color balance is Moreover, the irregularity of the unit pixels results in a rather unnatural display. Even if we tried to remove this unnaturalness with an external drive circuit, the circuit would become extremely complicated.
Furthermore, since the problem lies in the color filter arrangement, it is difficult to fundamentally solve the problem.

In this respect, in the pattern of FIG. 9(a), by using 3×3 pixels as basic display dots, it is possible to display characters more easily. However, since nine unit pixels are required for each RGB basic display dot, problems arise in terms of resolution and deterioration of information in the display panel.

(Problems to be Solved by the Invention) As described above, the conventional active matrix liquid crystal display device has a problem in that it is difficult to display easy-to-read color characters without reducing the resolution and amount of information.

An object of the present invention is to provide an active matrix liquid crystal display device that solves these problems.

[Structure of the Invention (Means for Solving Problems)] In the active matrix liquid crystal display device according to the present invention, address lines and data lines are not included in the unit display dot area of the active matrix substrate.
It is characterized by arranging at least three display N poles for R, G, and B.

(Function) In the conventional configuration, since one display electrode is arranged in a region sandwiched between adjacent address lines and data lines, the color filter arrangement is changed as shown in FIG. 9(a) or (b). Therefore, it was not possible to achieve both color balance and resolution in character display. On the other hand, in the present invention, display electrodes for R, G, and B are arranged between adjacent address lines and data lines to form one display dot. Either G or B can be displayed. Therefore, by making the shape of the display dot square and setting the areas of the three display electrodes within the square to be equal, color balance can be improved when displaying characters. Moreover, one display dot is 3
Since it is composed of two display electrodes, there is little deterioration in resolution or amount of information.

(Example) The present invention will be explained in detail below.

FIG. 1 isometrically shows the schematic structure of an active matrix substrate according to an embodiment. In the figure, G(Gi-1, Gi
, Gi+1,...) are address lines, D(Di-4
, []i, Di+1,...) are data lines that intersect with the address lines, the address line Qi is connected to the gates of the plurality of TPTs in the i row, and the data line Di is connected to the plurality of TPTs in the i column. connected to the drain of R in the diagram
, G, and B are display electrodes, each connected to an independent TPT source, and aligned with an R, 0.8 color filter provided on a counter substrate (not shown).

As shown in the figure, three display electrodes of R, G, and B are arranged with equal areas to form a square as a whole, and display dots P (Pi, i, PLi+2, Pi+2, .
i, p i+2. i+2,...) are configured.

This will hereinafter be referred to as a trio display dot.

There are no address lines or data lines within the trio display dots P, and two address lines G and two data lines are arranged between each trio display 6781.

Therefore, the R, G, and B display electrodes in each trio display dot P are independently selected by specific address lines and data lines.

FIGS. 2(a) and 2(b) show the structure of an active matrix substrate of a more specific embodiment. (a) is a plan view of one of the trio display dots pi and i in FIG. 1 and the surrounding address lines and data lines;
-A' sectional view.

1 is a transparent glass substrate, on which a layer with a thickness of 1500
Address line 2 that also serves as a gate electrode made of human MOII
is formed into an array. After this, a CVD5 i02 film 3 with a thickness of 1500 nm is deposited on the entire surface as a gate insulating film, and then a
-sI eyes are deposited. The a-S'i film 4 is patterned leaving it in each TFT section as shown. After this IT
R1G, B display electrode 5R using transparent conductive film such as O
, 50, 58 are formed.

Three display electrodes 5R within one trio display dot.

5 (1 and 5B are patterned so that they have the same area and are square as a whole. After this, the A2 film is deposited,
By patterning, the data line 6 and a-
A drain electrode 6' extending over the 8il 14 and a source electrode 7 connected from the a-8t film 4 to the display electrode are formed. Finally, a passivation layer 118 is formed, and openings 9 for trio display dots are provided therein to complete the active matrix substrate.

A display device is obtained by arranging a counter electrode substrate with a color filter aligned with the display electrodes to face the active matrix substrate configured as described above, and filling the liquid crystal with the active matrix substrate, as in the conventional case.

According to this embodiment, a trio display dot consisting of a set of R, G, and B display electrodes has a square shape suitable for character display, and each display electrode has an equal area and is controlled independently. It has become.

Therefore, compared to the conventional example, it is possible to display characters that are well balanced and easy to read. It is also possible to set the shape of the trio display dot to a rectangle other than a square, or to appropriately select the area of each display electrode according to the display intensity, thereby making it possible to set the color balance appropriately. can. Moreover, in terms of spatial resolution, it is equivalent to the case where one display dot is composed of 2×2 pixel electrodes when using the conventional method shown in FIG. 9(b), and 3 times when using FIG. 9(a).
Higher resolution can be obtained than in the case where one display dot is composed of ×3 pixel electrodes.

Further, in this embodiment, there is no wiring within the trio display dots, so the spacing between the display electrodes and electrodes within the trio display dots is narrow, and there are two wires between the trio display dots, so the spacing is large. This also makes the character display easier to read. Further, in this embodiment, as shown in FIG. 3(a), the interval I2a between adjacent display electrodes within one trio display dot area can be made smaller than the wiring interval and the interval between the wiring and the display electrode J2b. This is because the display electrode spacing λa is determined by the exposure-etching process of one conductor layer. The distance between the electrodes and wiring within the range L1 of one trio display dot is 3.lambda.b+28. On the other hand, in the conventional example in which wiring lines and display electrodes are arranged alternately, when a display dot is composed of two pixels, as is clear from FIG. The 0 interval of is 4Qb. Therefore, this embodiment allows for a larger display area. Furthermore, since one opening on the display electrode is provided on each of the three electrodes, the effective display area is large.

The present invention is not limited to the above embodiments.

FIG. 4 shows various examples of display electrode and color filter arrangements in the arrangement of trio display dots. These may be used appropriately depending on the purpose and use.

Further, for example, as shown in FIG. 1, the elongated display electrode within the trio display dot can be divided into upper and lower halves so that they can be independently controlled by different TPTs. In this case, one color filter may be placed opposite the two divided display electrodes. This configuration provides higher spatial resolution and is particularly useful for video display and the like.

FIG. 5 shows the configuration of an embodiment in which the number of data lines is reduced, corresponding to FIG. 1. In FIG. 1, two data lines are provided for one trio display dot, whereas in this embodiment, two data line portions and one data line portion are arranged alternately, and one data line portion is arranged alternately. Effectively 1.5 per trio display dot
It is used as the data line of the book. It is clear that the same effects as in the previous embodiment can be obtained by this method as well.

Furthermore, display quality can be improved by using a structure in which light is blocked by a black organic film, a metal layer, or the like in areas other than the openings of the active matrix substrate.

[Effects of the Invention] As described above, according to the present invention, it is possible to obtain an active matrix liquid crystal display device that can display color characters with good color balance without causing a decrease in spatial resolution or information content. .

[Brief explanation of drawings]

FIG. 1 is a diagram showing an equivalent circuit of an active matrix substrate according to an embodiment of the present invention, FIGS. 2(a) and (b) are diagrams showing a specific structural example thereof, and FIGS. ) is the reason for explaining the effect of this embodiment in comparison with the conventional example, and Fig. 4 (
a) to (C) are diagrams showing several examples of display electrode and color filter arrangement according to the present invention, FIG. 5 is a diagram showing an equivalent circuit of an active matrix substrate of another embodiment, and FIG. 6 is an active matrix type Basic equivalent circuit diagram of liquid crystal display device,
FIG. 7 is a diagram showing the configuration of the memory circuit section, FIG. 8 is a timing diagram for explaining the display operation, and FIG.
FIGS. 3A and 3B are diagrams illustrating examples of color filter arrangement in conventional color display. Applicant's agent Patent attorney Takehiko Suzue No. 1 Figure 3 Figure 4 Dl Deor Dl, 2
Doe3 Figure 5 6th Prisoner

Claims (4)

[Claims] (1) A plurality of address lines, a plurality of data lines that intersect with these address lines, a thin film transistor controlled by the selected address line, and a data signal from the data line is applied through this transistor. In a liquid crystal display device using an active matrix substrate on which display electrodes are integrated, at least three display electrodes for red, blue, and green are arranged without including the address line and data line in one display dot. An active matrix liquid crystal display device characterized by: (2) The active matrix display device according to claim 1, wherein the display dot area having the three display electrodes is rectangular. (3) The active matrix display device according to claim 1, wherein the display dot area having the three display electrodes is square. (4) 3 within the display dot area including the three display electrodes.
2. The active matrix liquid crystal display device according to claim 1, wherein the areas of the two display electrodes are set to be equal.