JPS59200222A - Display method of color liquid crystal - Google Patents

Abstract

PURPOSE:To compensate the variance of color due to the variance or production by controlling the gain of a video amplifier and the bias for every color to control a voltage, which is applied to a color liquid crystal cell, and colors to be mixed. CONSTITUTION:Individual filter electrodes in a liquid crystal are driven by means 11-13, and analog switches SWs 14, counters 15-17, decoders 18 and 19, and potentiometers 22 and 23 are provided. Gain and biases of video amplifiers 21 for individual colors are controlled to control voltages applied to the color liquid crystal cell and control colors to be mixed. When the applied voltage between electrodes on a liquid crystal layer is between Vth and Vth+Vsig, the transmittance is indicated by an approximately straight line. In this manner, the voltage applied to the color liquid crystal cell is controlled to control colors to be mixed after the gain and the bias of the video amplifier for every color are controlled. The white balance on the whole of a picture can be adjusted or colors can be changed and adjusted positively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of controlling voltage applied to a color liquid crystal cell.

Normally, LCD color display (d, red (R,) green (G), blue (
It is performed using the six primary colors of Bl. R,, (), 13-6
Colors are displayed in color in CR and T, but
In liquid crystals, each cell can be colored arbitrarily, so it is not necessarily necessary to use only six colors of R, G, and B, but the purpose of the present invention is to color i! of mixed colors. Since this is a II control, the case of RGB will be explained as an example.

For liquid crystal color display, R, GB color fill letters are visible on the surface of the transparent conductive film on the inner surface of the panel glass.

Due to variations in the manufacturing process, the color density (thickness) of the five colors, the thickness of the liquid crystal layer, and the area of transmitted or reflected light for each pixel and each color cannot be uniform, so the same signal is applied to the six colors. However, you may not be able to obtain the desired neutral color.

Furthermore, even though the color is the same, the perception of white differs depending on individual differences and race/ethnicity, so it is necessary to be able to make adjustments corresponding to these differences.

In manufacturing, there is a limit to keeping the thickness of the R, G, and B color filters, the thickness of the liquid crystal, and the area of transmitted or reflected light flux for each pixel or each color constant due to manufacturing costs.

Furthermore, due to the manufacturing process, JG and B filters are manufactured by dyeing each color using a dyeing solution of each color. It is very difficult to dye while maintaining the 79 lance.

If it is cold, the dyeability of each color dye in each dyeing solution and the auxiliary agents added to the dyeing solution to promote dyeing differ depending on the dyeing solution, so the degree of moisture protection imparted to the layer to be dyed differs. It is.

Furthermore, if the number of cells is large and the area of the liquid crystal is large, the thickness of the same filter may vary depending on the location.

An object of the present invention is to achieve uniform color balance. Since this is not a driving method itself, a known technique may be used for driving the liquid crystal area, and since it is not the purpose of the present invention, it will not be described.

Figure 1 shows an example of the structure of a color liquid crystal.
)′ is the substrate, (21(2+′) is the transparent electrode, (3)(3
)' is an alignment film, (4) is a single layer of 1 led filter,
(5) is a 131uc filter, (6) is a Gr filter.
een color filter layer, (7) is liquid crystal layer, (8) (
8) ' is a polarizing plate. 1. Figure 2 is a diagram showing the relationship between the voltage applied to the liquid crystal layer (applied voltage) and the transmittance, and shows the difference in characteristics due to the difference in film thickness of a color filter layer, especially the difference in characteristics due to the presence or absence of a colored layer. It shows.

From Figure 2, between the electrodes in Figure 1 of the liquid crystal layer +2) (2) '
From the applied voltage vth between Vth to Vsig,
It can be seen that the transmittance is almost a straight line.

In reality, the area of the transparent electrode (2)' in Figure 1, the film thickness of the single layer of the Zular filter (4) (51 (6)), the liquid crystal layer (7
) varies depending on location. Therefore, Ic,
The light amount balance between a and B may not be as desired.

On the other hand, there is also a desire to actively change the light intensity balance of 1'(, G, +3. FIG. 6 shows an embodiment of the present invention that satisfies this desire.

(11) (12) G3) shows the driving of each filter' electrode in the liquid crystal. (14) is analog S~■, (
15) (16) (17) are counters, (18) (19)
is a decoder, (20) is a NOT circuit, (21) is an id video amplifier, (22)! 23+ is a potentiometer,
(241'251 !2[i) is resistance, (2η is Amp
, (28) to (31) are analog Sw.

Cn, T color receivers are widely used in households today;
When MH2 is the clock Ck, the horizontal synchronization pulse is I-1, and the vertical synchronization pulse is ■, the counter (+5)
For horizontal synchronization, use 3.5 RJHz as Ck.
The ξ pulse I-1 is used as a clear signal, and the counter (1
The output of 5) is input to a decoder (18), and the decoder 08) outputs gate signals Hp, 1-ip2 to I-I pn, which are used as gate signals of analog Swα4).

Similarly, the counter (16) calculates the horizontal synchronization pulse 1
1 as a clock and the vertical synchronization pulse ■ as a clear signal, the gate signal Vl)I Vp2~■ is generated from the decoder (circle).
The intersection of the analog Sw (IJ') and the gate signal H1)I1-11)2 to I-1po and the gate signal Vl)IVl)2 to Vl)m is As shown in Figure 2, the voltage from vth to Vth + Vs ig is R
, H5Rヮ8.

Vidco Amp (21) is required for each color (R, C), and B, but since the configuration is the same, only the general one is shown.

CRT color receiver, "NT S C->RGB J
The image signal is separated into six colors of It OB by means such as a decoder, and the R signal is converted into Video as R51g.
Amr) +21).

The potentiometer (22) is connected to the liquid crystal characteristic V shown in Figure 2.
The gain of sig is controlled, and the potentiometer (23) controls the bias of the amplifier, that is, the Vth. .

By doing so, Vth -1-Vsig'x 几2 is output, and R■(s
TLvs is applied to the selected cell of the decoder-118)09).

counter (17) and NOT circuit 120) and analog S
~V (28) to (31) are 6 degrees, which makes the average voltage applied to the liquid crystal zero (the DC component is zero). Any of the known techniques such as division 1 driving using backup memory, simple matrix 1 driving, active matrix driving method, time division driving method, etc., may be used. Since it is not, I will not discuss it.

As explained above, the potentiometers 022+L23+ in FIG. 6 are used to adjust the whiteness and brilliance of the entire screen, or to actively change and adjust the colors by adjusting each color individually.

The adjustment for each color has been described above, but the adjustment for each pixel will now be described.

FIG. 4 is a diagram showing another embodiment of the present invention.

Compared to FIG. 6, RAM (321 or ROM) is added, and (33) and (34) are digital potentiometers, respectively.
6, RAM C32), which is replaced with 2+(23), outputs a digital signal to be controlled for each color. The output signal is the analog 8w inside the digital potentiometer (33)C34)
(35) f36), weight resistance (37) and resistance (
39), Vsig' is obtained by controlling R51g, and vth
control.

RAM (3a is a potentiometer (33) C34 for each cell depending on the white balance or display position) to control vth and Vsig to control the display. Control data can be entered using known techniques (not shown). , V
Although an analog amplifier is used as the ideo Amp (21), it goes without saying that it can be configured using a digital circuit.

As described above, according to the present invention, it is possible not only to correct color variations caused by manufacturing variations in liquid crystals, but also to actively prevent color fog, and to partially change color fog or color density. A unique display can be displayed on the video being played.

It can handle not only signal sources such as TV broadcasts, but also signals from color scanners, etc. Furthermore, it can be used not only for additive color mixing of RGB, but also for subtractive color mixing of YMC and other mixed color systems.

[Brief explanation of the drawing]

Figure 1 shows the color LCD 111! Figure 2 is a diagram showing the structure of the color liquid crystal, and Figure 37E'-rJ' is a diagram showing the characteristics of the color liquid crystal.
l (Mlri,, *'jll!J'117) 141
(4) (5) (6) Single layer color filter, (8) Polarizing plate, (11) (12) (+3) Liquid crystal (
2υVideo hnr) (22) Kyo potentiometer, C321It AM. (33) (341 Digital potentiometer Figure A, Figure Z

Claims (3)

[Claims] (1) A color liquid crystal display method characterized by controlling the gain and bias of a video amplifier for each color depending on the selected color such as the primary color, and controlling the voltage applied to the color liquid crystal cell to control the colors to be mixed. . (2) Claim (1) characterized in that a constant color is displayed by controlling the voltage applied to the 6 primary color cells, the gain of the video amplifier for each color, and the 2 ias. Method described. (3) Claim (1) characterized in that the voltage applied to each cell, the gain of the amplifier, and the bias are controlled for each cell to display the negative color. Or the first (
The method described in section 2).