JP3962484B2 - Liquid crystal device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal device including a liquid crystal element, and relates to color tone adjustment of a liquid crystal element that displays a color image based on digital display data.
[0002]
[Prior art]
In recent years, matrix type displays using liquid crystals (TFT, STN, FLC, AFLC, etc.) have made remarkable progress in terms of size and capacity.
[0003]
For example, screen sizes with a diagonal size of 10 to 14 inches for notebook PCs and 13 to 20 inches for desktop monitors have appeared, and in terms of display capacity, XGA (1024 × 768 pixels), SXGA (1280) × 1024) and even UXGA (1600 × l280) have been announced.
[0004]
As described above, liquid crystal displays that are comparable to CRTs in terms of screen size and display capacity will require further improvements in image quality as monitors, and are generally installed in CRT monitors and the like. More and more cases are equipped with image quality (ex. Color tone) adjustment functions.
[0005]
Incidentally, when image quality adjustment is performed on a liquid crystal monitor which is an example of a liquid crystal device, basically two methods are conceivable. One of them is a method of performing gain adjustment or the like in an analog manner at a video signal input unit in the case of a liquid crystal monitor having an analog input similar to a general CRT monitor.
[0006]
In the other case, in the case of a liquid crystal monitor having a so-called digital interface in which display data is inputted digitally, a simple MPU (microcontroller) 109 inside the liquid crystal monitor 100, as shown in FIG. This is a method of converting (correcting) display data from the display data generation unit 105 by providing a conversion table (lookup table: LUT) in a RAM (not shown) of the display data conversion circuit 110. In the case of this method, setting data for the conversion table is determined and set by the MPU 109 in accordance with, for example, adjustment data from the color tone adjustment SW (adjustment trimmer) 107.
[0007]
Here, in general, there are many cases in which adjustment is performed digitally because of the stability of control and the matching with the device (liquid crystal) drive system, and even if the input of the liquid crystal monitor is analog, the input section In some cases, an A / D converter is provided to perform correction by digital processing similar to the latter.
[0008]
[Problems to be solved by the invention]
However, in such a conventional liquid crystal device, when image quality adjustment is performed, for example, when R (red), G (green), and B (blue) color tone adjustment is performed, the adjustment by the digital method has a degree of freedom of adjustment. On the other hand, there is a problem that the control becomes complicated and the cost of the components is increased because the MPU, the RAM for the lookup table, etc. are used.
[0009]
The present invention has been made to solve such problems, and an object of the present invention is to provide a liquid crystal device capable of adjusting the red, green, and blue color tone of a color image by an inexpensive and simple method. It is what.
[0010]
[Means for Solving the Problems]
The present invention includes a liquid crystal element for displaying a color image based on the digital display data, and the information signal output means for outputting the information signal based on the digital display data to the liquid crystal element, the color image of red, green and blue Color tone adjusting means for outputting color correction data of a plurality of bits for independently adjusting the color tone, and display data correction for correcting the digital display data with the color correction data from the color tone adjusting means and outputting it to the information signal output means And the color correction data includes a bit indicating an increase / decrease amount of the information signal value, and the display data correction unit is configured to correct the color correction on the lower bit side of the digital display data. The correction is performed by extending the number of bits indicating the increase / decrease amount of the data information signal value .
[0011]
Further, the present invention is characterized in that the display data correction means performs correction for increasing or decreasing the information signal value by the color correction data so as to adjust the red, green and blue color tones.
[0013]
The present invention also provides 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, and red, green and blue colors of the color image. Color tone adjustment means for outputting color correction data of a plurality of bits for independently adjusting the color tone of the image, and display data for correcting the digital display data with the color correction data from the color tone adjustment means and outputting it to the information signal output means The information signal output means has a data input unit having a number obtained by adding the number of bits of the color correction data to the number of extended bits of the color correction data. It is what.
[0014]
Further, as in the present invention, a plurality of bits of color correction data for independently adjusting the red, green and blue color tones of the color image are output by the color adjustment means, and the digital display data is converted by the display data correction means. After correction by the color correction data, an information signal based on the digital display data is output to an information signal output means for outputting to the liquid crystal element.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the invention will be described with reference to the drawings.
[0016]
FIG. 1 is a schematic diagram of a liquid crystal monitor which is an example of a liquid crystal device according to the first embodiment of the present invention. In the figure, 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 diagonal, and the number of pixels is XGA (1024 × 768).
[0017]
Reference numeral 105 denotes a display data generation unit such as a personal computer. The display data generation unit 105 receives digital display data 1 (ID (5: 0), ID (15:10), ID (25:20), R (red), G (green), B (blue) 6 bits / pixel) and control signals (horizontal and vertical synchronization signals, transfer clocks, blanking signals, etc.) are sent to the liquid crystal monitor 100.
[0018]
Reference numeral 107 denotes a color tone adjustment SW which is a color tone adjustment means. This color tone adjustment SW 107 is composed of a digital code SW, and is 3-bit color correction data for independently adjusting the color tone of each of the R, G and B colors ( CD (2: 0), CD (12:10), and CD (22:20)) are output for RGB. The most significant bit of the 3-bit color correction data for each color is a so-called sign bit, which represents the polarity (correction direction) of the correction data.
[0019]
Reference numeral 108 denotes a display data correction circuit as display data correction means. The display data correction circuit 108 converts the digital display data 1 (6 bits / pixel) from the display data generator 105 into the remaining 2 of the color correction data. The data is expanded to 8 bits / pixel by bit / pixel, and is sent to the panel control circuit 104 as “display data 2”. The operation of the display data correction unit 108 will be described in detail later.
[0020]
Reference numeral 104 denotes a panel control circuit. The panel control circuit 104 outputs the display data 2 corrected by the display data correction circuit 108 to the information electrode driving circuit 102 which is an information signal output means, and a display data generating unit. Based on the control signal from 105, various control signals to the information electrode drive circuit 102 and the scan electrode drive circuit 103 are generated.
[0021]
Reference numeral 106 denotes a drive voltage generation circuit. The drive voltage generation circuit 106 generates a predetermined scan electrode drive voltage and an information electrode drive voltage based on a drive voltage control signal from the panel control circuit 104. This is supplied to the drive circuit 103 and the information electrode drive circuit 102.
[0022]
Then, the scan electrode drive circuit 103 and the information electrode drive circuit 102 are 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, respectively. A drive waveform is generated and applied to the scan electrode 101a and the information electrode 101b of the liquid crystal panel 101, and the liquid crystal panel 101 is driven at a predetermined frame frequency and drive voltage.
[0023]
The information electrode drive circuit 102 has a total display data input width of 8 bits, which is the number of bits (6 bits) of the original input data “display data 1” plus the extension of the color correction data (2 bits). Has a data input unit corresponding to.
[0024]
FIG. 2 is a block diagram showing the configuration of the information electrode drive circuit 102. The information electrode drive circuit 102 is supplied from the panel control circuit 104 as a data input unit corresponding to the 8-bit display data input width. A bidirectional latch selector 101A that operates in response to a shift direction switching signal, an enable input / output signal, and a clock signal, a data rearrangement circuit 102B that rearranges 8-bit display data 2, and display data 2 that is rearranged by the data rearrangement circuit 102B. A data register 102C for holding, a data latch unit 102D for latching display data 2 held in the data register 102C by a latch signal from the panel control circuit 104, a D / A converter 102E for D / A converting the latched data, and An output amplifier 102F is provided.
[0025]
In the figure, reference drive voltages V0 to V8 are voltages 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 10l. On the other hand, 8-bit display data for each color is latched by a latch signal (LP), but all 8 bits input to the information signal driving circuit 102 are display data, and the display data includes the correction data. It does not matter whether or not
[0026]
Here, the information signal driving circuit 102 selects one voltage range (Vn + 1 to Vn) of the γ correction voltage based on the latched 8-bit display data as shown in FIG. The bit outputs 256 kinds of voltages by further dividing 32 between Vn + 1 to Vn by D / A conversion. The relationship between the input display data and the output voltage is as shown in FIG.
[0027]
On the other hand, 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. Basically, the liquid crystal panel exhibits 256-level transmittance according to the 256 output voltages output from the information electrode driving circuit 102 described above. As shown in FIG. In many cases, γ = 1, rather than a slightly complicated S-shaped characteristic. Therefore, the reference drive voltages V0 to V8 are given for the purpose of adjusting the transmittance of the liquid crystal to change linearly.
[0028]
Incidentally, since the relationship between the output voltage and the liquid crystal transmittance is slightly different for each RGB color, in the present invention, the color tone is independently adjusted for each RGB color by using the color tone adjustment SW 107 and the display data expansion circuit 108. Adjustments are made.
[0029]
Here, the color tone adjustment SW 107 is a general digital code SW as described above, and outputs color correction data (digital code) of 3 bits for each color according to the adjustment position. Note that the color tone adjustment SW 107 can realize the same function by a combination of an analog trimmer (variable resistor) and an A / D converter.
[0030]
FIG. 6 is a code table of the color correction data CD (x2: x0) (R: x = 0, G: x = 1, B: x = 2) in the present embodiment. Here, among the 3 bits, the most significant bit CIDx2 represents the polarity (correction direction) of the correction data, and the remaining 2 bits represent the correction amount.
[0031]
7 and 8 are diagrams for explaining the operation of the display data correction circuit 108 in this embodiment.
[0032]
Here, as described above, the display data correction circuit 108 receives display data 1 (6 bits for each color of RGB in this embodiment) and color correction data (3 bits for the same). When the most significant bit of the color correction data is “0”, correction is performed in the positive direction of the transmittance characteristic of FIG. 5, and when it is “1”, correction is also performed in the negative direction.
[0033]
FIG. 7 is a processing flow in the case where plus correction is performed. Here, plus correction refers to a direction in which the output voltage (liquid crystal drive voltage) for input display data is increased as compared to the case without correction, and the transmittance of the liquid crystal is increased.
[0034]
The flow will be described below.
[0035]
When correction is performed, the display data correction circuit 108 first determines that the correction is positive because the most significant bit of the color correction data is “0”. The 6-bit display data 1 shown is shifted to the upper bit side by 2 bits as shown in (b), and the lower 2 bits are filled with “1”.
[0036]
After that, as shown in (c), 2 bits of the color correction data from the color tone adjustment SW 107 are subtracted into the lower 2 bits, and the result is converted into 8-bit display data 2 shown in (d), and the result is sent to the panel control circuit 104. Output. Although not particularly illustrated, the above processing can be realized by simple hardware “bit shift circuit” and “addition / subtraction circuit”.
[0037]
On the other hand, FIG. 8 is a processing flow in the case where minus correction is performed.
[0038]
When the correction is performed, the display data correction circuit 108 first determines that the correction is negative because the most significant bit of the color correction data is “1”, and is input from the display data generation unit 105 in FIG. Is shifted to the upper bit side by 2 bits as shown in (b), and the lower 2 bits are filled with “0”.
[0039]
Thereafter, as shown in (c), 2 bits of the color correction data from the color tone adjustment SW 107 are added to the lower 2 bits, and the result is converted into 8-bit display data 2 shown in (d), and the panel control circuit 104 receives the result. Output.
[0040]
FIG. 9 is a table showing the relationship between the input data (6 bits) to the display data correction circuit 108 at the time of the plus correction and the output data (8 bits) after the color adjustment processing.
[0041]
As an example, when the input data is “07H”, the output voltage without correction is “V7”, and the maximum output voltage (+3 in FIG. 6) is “V7 + (V8−V7) × 3/32”. It is. That is, when the correction is performed to the maximum in the plus direction, the output voltage is increased by “(V8−V7) × 3/32” compared to the case where the correction is not performed, and the transmittance of the liquid crystal is changed (up) accordingly.
[0042]
As described above, in this embodiment, it is possible to adjust the color tone in three stages in the plus direction and the minus direction in units of 1 LSB of 8 bits (256 types) for one input data. FIG. 10 is a conceptual diagram showing changes in the transmittance characteristics of the liquid crystal when such correction is performed.
[0043]
In the present invention, this correction processing is performed independently for each of RGB (of course, the R display data is processed by the R color correction data). As a result, the voltage-transmittance characteristics that have been slightly different for each of the RGB colors can be corrected and matched, and display with a color balance maintained at all gradation levels is possible.
[0044]
In this way, the color correction data for independently adjusting the RGB color tones are output by the color tone adjustment SW 107, and the display data is corrected by the color correction data in the display data correction circuit 108, whereby the MPU and the lookup table RAM are corrected. The color tone can be adjusted independently of RGB by an inexpensive and simple method without using the above.
[0045]
Next, a second embodiment of the present embodiment will be described.
[0046]
In the present embodiment, the number of bits of 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.
[0047]
11 and 12 show a processing flow of the display data correction circuit 108 in this embodiment.
[0048]
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, color correction is performed on the input display data 1 (6 bits). While the data (2 bits) is expanded to a total of 8 bits, the present embodiment is the same in that the display data width after correction processing is 8 bits, but the display data is an arithmetic process. The arithmetic processing is performed so that the MSB side 2 bits of the color correction data overlap with the 1 LSB side 2 bits.
[0049]
By performing such arithmetic processing, it is possible to perform correction in a wider range at the same correction pitch as in the first embodiment.
[0050]
Along with the first and second embodiments, a configuration in which 6-bit display data is extended to 2 bits as correction data and output to the information electrode driving circuit 102 as 8-bit display data in total. However, this is merely an example, and it goes without saying that the number of bits is not limited in concept. For example, the input display data may be 8 bits and output to the information electrode drive circuit 102 as corrected 10-bit display data.
[0051]
【The invention's effect】
As described above, according to the present invention, the color tone adjusting means and the display data correcting means are provided, and in the display data correcting means, the red, green, and blue color tones of the color image output by the color tone adjusting means are independent of each other. Since the digital display data can be corrected by the color correction data to be adjusted in the following manner, the color tone can be adjusted independently for red, green and blue by a cheaper and simple method.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a liquid crystal monitor which is an example of a liquid crystal device according to a first embodiment of the 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 illustrating a voltage output from 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 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 driving circuit and the transmittance of the liquid crystal panel.
FIG. 6 is a table showing an example of color correction data output from a color tone adjustment SW of the liquid crystal monitor.
FIG. 7 is a diagram for explaining an operation when performing positive correction of a display data correction circuit of the liquid crystal monitor.
FIG. 8 is a diagram for explaining an operation when the display data correction circuit performs 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 the liquid crystal panel.
FIG. 11 is a diagram for explaining an operation when performing positive correction in a display data correction circuit of a liquid crystal monitor according to a second embodiment of the present invention.
FIG. 12 is a diagram for explaining an operation when the display data correction circuit performs a negative correction.
FIG. 13 is a schematic diagram of a liquid crystal monitor including a conventional color correction circuit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 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 generation part 107 Color tone adjustment SW
108 Display data correction circuit

Claims (3)

Each independently a liquid crystal element for displaying a color image based on the digital display data, and the information signal output means for outputting the information signal based on the digital display data to the liquid crystal element, the red of the color image, green and blue shades A color tone adjusting unit that outputs a plurality of bits of color correction data to be adjusted, and a display data correcting unit that corrects the digital display data with color correction data from the color tone adjusting unit and outputs the corrected data to the information signal output unit. A liquid crystal device comprising:
The color correction data has a bit indicating an increase / decrease amount of the information signal value, and the display data correction means has a bit number indicating an increase / decrease amount of the information signal value of the color correction data on the lower bit side of the digital display data. The liquid crystal device is characterized in that the correction is performed by expanding the function . The liquid crystal device according to claim 1, wherein the display data correction unit performs correction to increase or decrease the information signal value according to the color correction data so as to adjust the color tone of the red, green, and blue. A liquid crystal element that displays a color image based on digital display data, an information signal output means that outputs an information signal based on the digital display data to the liquid crystal element, and the red, green, and blue tones of the color image are independent of each other A color tone adjusting unit that outputs a plurality of bits of color correction data to be adjusted, and a display data correcting unit that corrects the digital display data with color correction data from the color tone adjusting unit and outputs the corrected data to the information signal output unit. A liquid crystal device comprising:
It said information signal output means, a liquid crystal device you further comprising a data input unit number plus number of extension bits of the color correction data to the number of bits of the digital display data.

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