JP2000010532A - Liquid crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal device capable of tone adjustment of a color image independently in R(red), G(green) and B(blue) by an inexpensive and simple method. SOLUTION: The device outputs color correction data in plural bits independently adjusting each tone of the red, green and blue of a color image by a tone adjusting means 107, while digital display data are corrected through this color correction data by a display data correcting means 108. After that, the information signals on the basis of the digital display data are outputted to the information signal outputting means 102 for outputting to liquid crystal device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device having a liquid crystal element, and more particularly to a color tone adjustment of a liquid crystal element for displaying a color image based on digital display data.

[0002]

2. Description of the Related Art In recent years, matrix-type displays (TFT, STN, FLC, AFLC, etc.) using liquid crystal have made remarkable progress in terms of increasing the size and capacity.

For example, screen sizes of 10 to 14 inches diagonal for notebook PCs and more than 13 to 20 inches for desktop monitors have appeared, and XGA (1024 × 768 pixels), SXGA (1
280 × 1024) and UXGA (1600 ×
l280).

[0004] As described above, the liquid crystal display, which has become comparable to the CRT in terms of screen size and display capacity, is required to further improve the image quality as a monitor in the future.
Increasingly, an image quality (ex. Color tone) adjustment function, etc., which is very commonly installed in RT monitors and the like, is installed.

When adjusting the image quality using a liquid crystal monitor, which is an example of a liquid crystal device, there are basically two methods. In the case of a liquid crystal monitor having an analog input similar to that of a general CRT monitor, one of the methods is a method in which a video signal input section performs processing such as gain adjustment in an analog manner.

On the other hand, in the case of a liquid crystal monitor having a so-called digital interface to which display data is input digitally, a simple MPU (microcontroller) is provided inside the liquid crystal monitor 100 as shown in FIG.
109 and a RAM (not shown) of the display data conversion circuit 110
Is provided with a conversion table (lookup table: LUT), and the display data from the display data generation unit 105 is converted (corrected). In the case of this method, the setting data in the conversion table is stored in the MPU 109 according to the adjustment data from the color tone adjustment SW (adjustment trimmer) 107, for example.
Is determined and set.

Here, in general, in many cases, adjustment is performed digitally because of the stability of control and the good matching with the device (liquid crystal) driving method, and even if the input of the liquid crystal monitor is analog. In some cases, an A / D converter is provided in the input unit, and correction is performed by digital processing similar to the latter.

[0008]

However, in such a conventional liquid crystal device, when adjusting the image quality, for example, when adjusting the color tone of R (red), G (green), and B (blue), a digital system is used. Has a high degree of freedom in adjustment, but has problems such as complicated control and high component cost due to the use of an MPU, a look-up table RAM, and the like.

The present invention has been made to solve such a problem, and provides a liquid crystal device capable of adjusting the red, green, and blue tones of a color image by an inexpensive and simple method. The purpose is to do so.

[0010]

According to the present invention, there is provided a liquid crystal device having a liquid crystal element for displaying a color image based on digital display data, and an information signal for outputting an information signal based on the digital display data to the liquid crystal element. An output unit, a color adjustment unit that outputs a plurality of bits of color correction data for independently adjusting the red, green, and blue tones of the color image, and the digital display data based on the color correction data from the color adjustment unit. Display data correction means for correcting and outputting to the information signal output means.

Further, the present invention is characterized in that the display data correction means performs correction for increasing or decreasing the voltage of the information signal by the color correction data so as to adjust the red, green and blue colors. is there.

Further, according to the present invention, the color correction data has a bit indicating an increase / decrease amount of an information signal voltage, and the display data correction means includes an information signal of the color correction data on a lower bit side of the digital display data. The correction is performed by expanding the number of bits indicating the amount of increase or decrease of the voltage.

Further, according to the present invention, the information signal output means includes:
It is characterized by having a data input section of a number obtained by adding the number of bits of the digital display data to the number of expansion bits of the color correction data.

Further, as in the present invention, a plurality of bits of color correction data for independently adjusting the red, green and blue tones of a color image are output by the color tone adjusting means, and the digital display data is adjusted by the display data correcting means. Is corrected by the color correction data, and an information signal based on the digital display data is output to an information signal output unit that outputs the information signal to the liquid crystal element.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a liquid crystal monitor as an example of a liquid crystal device according to the first embodiment of the present invention. In FIG. 1, reference numeral 101 denotes a liquid crystal panel which is a liquid crystal element. The liquid crystal panel 101 is a so-called active matrix type liquid crystal panel in which switching elements such as thin film transistors are arranged in each pixel. The display area is about 13 inches diagonally and the number of pixels is X
GA (1024 × 768).

Reference numeral 105 denotes a display data generator such as a personal computer.
From 05, digital display data 1 (ID (5: 0),
ID (15:10), ID (25:20), R (red),
G (green) and B (blue) colors of 6 bits / pixel) and control signals (horizontal and vertical synchronization signals, transfer clocks, blanking signals, etc.) are sent to the liquid crystal monitor 100.

Reference numeral 107 denotes a color tone adjustment switch which is a color tone adjustment means.
3-bit color correction data (CD (2: 0), CD (12:10), and CD (12:10), respectively, for RGB) configured by a code SW and independently adjusting the color tone of each of R, G, and B colors.
(22:20)). Note that the most significant bit of the three-bit color correction data for each color is a so-called sign bit, and represents the polarity (correction direction) of the correction data.

Reference numeral 108 denotes a display data correction circuit which is a display data correction means.
Converts the digital display data 1 (6 bits / pixel) from the display data generator 105 into the remaining 2 bits of the color correction data.
The data is expanded to 8 bits / pixel by bits / pixel and sent to the panel control circuit 104 as "display data 2". The operation of the display data correction means 108 will be described later in detail.

A panel control circuit 104 includes a display data correction circuit 108.
The display data 2 corrected by the above is output to the information electrode drive circuit 102 which is an information signal output unit, and various signals to the information electrode drive circuit 102 and the scan electrode drive circuit 103 are supplied based on a control signal from the display data generation unit 105. Generate control signals.

Reference numeral 106 denotes a drive voltage generation circuit.
This drive voltage generation circuit 106
A predetermined scan electrode drive voltage and a predetermined information electrode drive voltage are generated based on the drive voltage control signal from the controller and supplied to the scan electrode drive circuit 103 and the information electrode drive circuit 102, respectively.

The scan electrode drive circuit 103 and the information electrode drive circuit 102 respectively control the scan electrode drive waveform based on each drive voltage from the drive voltage generation circuit 106 and various control signals and display data from the panel control circuit 104. Then, an information electrode driving waveform is generated and applied to the scanning electrodes 101a and the information electrodes 101b of the liquid crystal panel 101, and the liquid crystal panel 101 is driven at a predetermined frame frequency and a driving voltage.

It should be noted that the information electrode drive circuit 102 uses the bit number (6) of the original input data "display data 1".
And a data input portion corresponding to a display data input width of a total of 8 bits obtained by adding an extension (2 bits) of the color correction data to the display data input width.

Here, FIG. 2 shows the information electrode driving circuit 102.
Is a block diagram showing a configuration of the information electrode driving circuit 102. The information electrode driving circuit 102 includes a shift direction switching signal, an enable input / output signal, and a clock signal from the panel control circuit 104 as a data input unit corresponding to the 8-bit display data input width. Bidirectional latch selector 101A that operates according to a data sorting circuit 10 that sorts 8-bit display data 2
2B, a data register 102C for holding the display data 2 rearranged by the data rearrangement circuit 102B, a data latch section 102D for latching the display data 2 held in the data register 102C by a latch signal from the panel control circuit 104, The latched data is
D / A converter 102E for A / A conversion and output amplifier 1
02F.

It should be noted that, in FIG.
V8 is a voltage input from the drive voltage generation circuit 106 in order to determine nine main points on the γ characteristic curve of the liquid crystal panel 101. On the other hand, display data of 8 bits for each color is latched by a latch signal (LP), but all 8 bits input to the information signal drive circuit 102 are display data, and the display data includes the correction data. It doesn't matter if it is.

Here, the information signal driving circuit 102 selects one voltage range (Vn + 1 to Vn) of the .gamma. Correction voltage based on the latched 8-bit display data by the upper three bits as shown in FIG. The lower 5 bits output 256 different voltages by further equally dividing Vn + 1 to Vn into 32 by D / A conversion. Note that the relationship between the input display data and the output voltage is as shown in FIG.

FIG. 5 is a diagram showing the relationship between the output voltage to the liquid crystal panel 101 and the transmittance of the liquid crystal. fundamentally,
256 output from the information electrode driving circuit 102 described above
The liquid crystal panel exhibits a transmittance of 256 levels according to the output voltage, but as shown in the figure, generally, this characteristic is not γ = 1, but has a rather complicated S-shaped characteristic. There are many. Therefore, the reference drive voltages V0 to V8 are provided for the purpose of adjusting the transmittance of the liquid crystal to change linearly.

Since the relationship between the output voltage and the liquid crystal transmittance is slightly different for each of the RGB colors, in the present invention, the color tone adjustment SW 107 and the display data expansion circuit 108 are used for each of the RGB colors. The color tone is adjusted independently.

Here, the color tone adjustment SW 107 is a general digital code SW as described above, and outputs 3-bit color correction data (digital code) for each color according to the adjustment position. Note that this color tone adjustment SW1
07 can also realize the same function by a combination of an analog trimmer (variable resistor) and an A / D converter.

FIG. 6 shows the color correction data CD (x2: x0) (R: x = 0, G: x =
1, B: x = 2). Here, of the three bits, the most significant bit CIDx2 indicates the polarity (correction direction) of the correction data, and the remaining two bits indicate the correction amount.

FIGS. 7 and 8 are diagrams for explaining the operation of the display data correction circuit 108 in the present embodiment.

Here, as described above, display data 1 (6 bits for each color of RGB in this embodiment) and color correction data (3 bits for the same color) are input to the display data correction circuit 108. Then, the most significant bit of the color correction data is
In the case of "0", the correction is performed in the plus direction of the transmittance characteristic in FIG. 5, and in the case of "1", the correction is similarly performed in the negative direction.

FIG. 7 is a processing flow when the plus correction is performed. Here, the plus correction refers to a direction in which the output voltage (liquid crystal drive voltage) for input display data is increased as compared with the case without correction, and the transmittance of the liquid crystal is increased.

Hereinafter, the flow will be described.

When performing correction, the display data correction circuit 10
In the display data generation unit 105, first, since the most significant bit of the color correction data is “0”, the correction is determined to be plus correction
The 6-bit display data 1 shown in (a) of FIG. 7 is shifted toward the upper bits by two bits as shown in (b), and the lower 2 bits are filled with "1".

Thereafter, as shown in (c), two bits of the color correction data from the color tone adjustment SW 107 are subtracted from the lower two bits, and the result is obtained as the 8-bit display data 2 shown in (d). Output to the circuit 104. Although not particularly shown, the above processing can be realized by simple hardware “bit shift circuit” and “addition / subtraction circuit”.

FIG. 8 is a processing flow for performing the minus correction.

When performing the correction, the display data correction circuit 108 first sets the most significant bit of the color correction data to “1”.
Therefore, it is determined that the correction is a minus correction, and the 6-bit display data 1 shown in FIG. 8A input from the display data generation unit 105 is shifted to the upper bit side by 2 bits as shown in FIG. 8B. , The lower two bits are padded with “0”.

Thereafter, as shown in (c), two bits of the color correction data from the color tone adjustment SW 107 are added to the lower two bits, and the result is obtained as the 8-bit display data 2 shown in (d). Output to the circuit 104.

FIG. 9 is a table showing the relationship between the input data (6 bits) to the display data correction circuit 108 during the plus correction and the output data (8 bits) after the color adjustment processing.

As an example, when the input data is "07H", the output voltage without correction is "V7", and the output voltage at the maximum plus correction (+3 in FIG. 6) is "V7 + (V8-V
7) × 3/32 ”. That is, when the correction is performed to the maximum in the plus direction, “(V8−V
7) The output voltage increases by “3/32”, and the transmittance of the liquid crystal also changes (increases) accordingly.

As described above, in the present embodiment, one input data corresponds to 8 bits (256 types) of 1 bit.
In LSB unit, 3 in each of plus direction and minus direction
Stepwise color tone adjustment is possible. FIG. 10 is a conceptual diagram illustrating a change in the transmittance characteristic of the liquid crystal when such correction is performed.

In the present invention, this correction process is performed independently for each of R, G, and B (of course, R display data is processed with R color correction data). As a result, the voltage-transmittance characteristics that were slightly different for each of the RGB colors can be corrected and matched, and a display with color balance maintained at all gradation levels has been made possible.

As described above, R is adjusted by the color tone adjustment SW 107.
By outputting color correction data for independently adjusting the color tone of GB and correcting the display data with the color correction data in the display data correction circuit 108, the M
The color tone can be adjusted independently of RGB by using a cheap and simple method without using a PU, a RAM for a look-up table, or the like.

Next, a second embodiment of the present embodiment will be described.

In the present embodiment, the number of bits of the color correction data of the color tone adjustment SW 107 in FIG. 1 is changed to 5 bits for each color of RGB. Note that the most significant bit of the color correction data indicates the direction of correction, as in the first embodiment described above.

FIGS. 11 and 12 show a processing flow of the display data correction circuit 108 in the present embodiment.

Here, the processing flow of the display data correction circuit 108 is the same as that of the first embodiment described above, but in the first embodiment, the input display data 1
(6 bits) by expanding the color correction data (2 bits)
In the present embodiment, the display data width after correction processing is 8 bits in contrast to the total of 8 bits, but the color correction data is added to the 2 bits on the LSB side of display data 1 in the calculation processing. The 2 bits on the MSB side perform the overlapping arithmetic processing.

By performing such arithmetic processing, it is possible to perform correction over a wider range at the same correction pitch as in the first embodiment.

In addition, together with the first and second embodiments, 6
With respect to the display data of bits, the extension as correction data is set to 2 bits, and a configuration is adopted in which the display data of a total of 8 bits is output to the information electrode drive circuit 102. However, this is merely an example, Needless to say, the number of bits is not limited to this. For example, the input display data is set to 8 bits,
You may make it output to the information electrode drive circuit 102 as bit display data.

[0051]

As described above, according to the present invention, a color tone adjusting means and a display data correcting means are provided. In the display data correcting means, red, green and blue of a color image outputted by the color tone adjusting means are provided. Since the digital display data can be corrected by the color correction data for independently adjusting the color tones, the color tone can be adjusted independently for red, green, and blue by a cheaper and simpler method.

[Brief description of the drawings]

FIG. 1 is a schematic view of a liquid crystal monitor as an example of a liquid crystal device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an information electrode driving circuit of the liquid crystal monitor.

FIG. 3 is a diagram showing a voltage output by the information electrode driving circuit in accordance with display data input to the liquid crystal monitor.

FIG. 4 is a diagram showing a relationship between display data and an output voltage of the information electrode driving circuit.

FIG. 5 is a diagram showing an example of the relationship between the output voltage of the information electrode drive circuit and the transmittance of a liquid crystal panel.

FIG. 6 is a table showing an example of color correction data output from a color tone adjustment switch of the liquid crystal monitor.

FIG. 7 is a view for explaining the operation when the display data correction circuit of the liquid crystal monitor performs a plus correction.

FIG. 8 is a diagram for explaining the operation of the display data correction circuit when performing a negative correction.

FIG. 9 is a table showing an example of a relationship between input data and output data of the display data correction circuit.

FIG. 10 is a diagram showing an example of the relationship between the correction direction of the display data correction circuit and the transmittance of a liquid crystal panel.

FIG. 11 is a view for explaining an operation in the case where a plus correction is performed in the display data correction circuit of the liquid crystal monitor according to the second embodiment of the present invention.

FIG. 12 is a diagram illustrating an operation of the display data correction circuit when performing a negative correction.

FIG. 13 is a schematic diagram of a liquid crystal monitor including a conventional color correction circuit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 liquid crystal monitor 101 liquid crystal panel 102 information electrode drive circuit 103 scan electrode drive circuit 104 panel control circuit 105 display data generator 107 color adjustment switch 108 display data correction circuit

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2H093 NA16 NA43 NA53 NC16 NC21 NC22 NC26 NC28 NC34 NC66 ND06 ND17 ND49 ND54 ND58 5C006 AA22 AF46 AF52 BC16 FA56 5C060 EA01 HB23 JA14 JA18 JA19

Claims (4)

[Claims] 1. A liquid crystal device comprising a liquid crystal element for displaying a color image based on digital display data, an information signal output means for outputting an information signal based on the digital display data to the liquid crystal element; Color tone adjusting means for outputting a plurality of bits of color correction data for independently adjusting the color tones of red, green and blue; and the information signal output means for correcting the digital display data with color correction data from the color tone adjusting means. A liquid crystal device comprising: a display data correction unit that outputs the data to the display device. 2. The display data correction unit according to claim 1, wherein the display data correction unit performs correction to increase or decrease the voltage of the information signal by the color correction data so as to adjust the red, green, and blue colors. Liquid crystal devices. 3. The display device according to claim 2, wherein the color correction data has a bit indicating an increase / decrease amount of an information signal voltage.
3. The liquid crystal device according to claim 1, wherein the correction is performed by extending the number of bits indicating the amount of increase or decrease of the information signal voltage of the color correction data to a lower bit side of the digital display data. 4. The liquid crystal device according to claim 1, wherein said information signal output means has a data input portion of a number obtained by adding an extension bit number of said color correction data to a bit number of said digital display data. apparatus.