JP2004109796A - Liquid crystal panel driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal panel driving device capable of performing optimization of output data (overdrive data) while a memory quantity of a lookup table is reduced. <P>SOLUTION: The high-order 4 bits of input data and the high-order 4 bits of a previous frame data from a frame memory 1 are given to the lookup table (LUT) 3 as an address. The lower-order 5 bits in the 10 bits data of the lookup table 3 are complement data. The 5 bits of the complement data of the lookup table 3 when the high-order 4 bits of the previous frame data and the high-order 4 bits of the input data are given to the lookup table 3 as the address, the lower-order 4 bits of the previous frame data and the lower-order 4 bits of the input data are inputted to a first arithmetic circuit 4 and the arithmetic result is inputted to a second arithmetic circuit 5 performing temperature correcting arithmetic processing to obtain an optimized overdrive data. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a liquid crystal panel driving device that drives a liquid crystal panel at high speed by overdrive.
[0002]
[Prior art]
In order to increase the speed of a liquid crystal panel, a technique for improving moving image display by performing overdrive driving to apply a voltage higher than a normal voltage has been proposed as shown in FIG. reference). Among such methods, as shown in FIG. 2, a frame memory 101 and a look-up table 102 are provided, and the overdrive data of the look-up table 102 includes the previous frame data (start data) and the input data (target data). In the configuration set based on the relationship (1), overdrive can be accurately applied.
[0003]
[Patent Document 1]
JP 2001-265298 A
[Problems to be solved by the invention]
However, in the above-described configuration in which a look-up table must be provided, when the previous frame data is 8 bits and the input data is 8 bits, the memory capacity is large (if the LUT is full for data of 8 bits of input and 8 bits of output). 2 ＾ 16 = 65536 bytes (× 3: RGB) memory capacity is required), resulting in high cost. On the other hand, if the upper 4 bits of the previous frame data and the upper 4 bits of the input data are used, the memory capacity can be reduced (2 ＾ 8 = 256 bytes (× 3: RGB)). However, in a configuration using such a memory as a look-up table, the lower 4 bits of the overdrive data are “0000”, and a step occurs in the overdrive gradation. That is, in the range of “xxxxxx0000” to “xxxxxx1111” in the input data (target grayscale) (in decimal notation, 0 to 15, 16 to 31,...), The same grayscale value is obtained. There is a problem that a streak occurs on a display scroll screen or the like. Also, a look-up table having different data values should be prepared according to the temperature state of the liquid crystal panel. However, if a look-up table is prepared for each certain temperature range, a larger memory capacity is required. Would.
[0005]
The present invention has been made in view of the above circumstances, and has as its object to provide a driving method capable of obtaining appropriate output data by reducing the memory capacity of a look-up table, and a liquid crystal panel driving device using such a driving method. I do.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a liquid crystal panel driving device according to the present invention performs overdrive using a frame memory and a look-up table. In the liquid crystal panel driving device, T is a current temperature, and Tm is a first parameter ( T) when f (T) is an intermediate value between A1 and A2, A1 is the overdrive grayscale at the reference temperature stored in the look-up table, A2 is the target grayscale, p is the second parameter, f When (T) is overdrive data after temperature correction, the temperature correction calculation processing is performed by the calculation formula of f (T) = (A1−A2) / (1+ (T / Tm) p) + A2. It is characterized by the following.
[0007]
With the above configuration, it is possible to obtain appropriate output data while reducing the memory capacity as compared with a configuration in which a plurality of lookup tables are prepared for each certain temperature range.
[0008]
Further, according to the liquid crystal panel driving device of the present invention, in a liquid crystal panel driving device that performs overdrive using a frame memory and a lookup table, data is output so that a part of output data from the lookup table becomes supplementary data. Is set, a part of the previous frame data and a part of the input data are given to the look-up table as an address, and the correction data is generated using a complementary data part in the output data from the look-up table, Based on this correction data and the non-complementary data portion from the lookup table, data that becomes overdrive at the reference temperature is generated, and a temperature correction corresponding to the current temperature is generated based on the overdrive data at the reference temperature. It is characterized by performing arithmetic processing.
[0009]
With the above configuration, both the memory capacity of the lookup table is reduced by reducing the address of the lookup table, and the memory capacity is reduced by eliminating the need to provide a plurality of lookup tables for each temperature range. I can plan.
[0010]
Compensation data is generated by a complementary data portion in the output data from the lookup table, an address non-use portion of the input data, and an address non-use portion of the previous frame data, and the correction data and the The overdrive data at the reference temperature is generated based on the non-complementary data portion, and the temperature correction calculation process corresponding to the current temperature is performed on the overdrive data at the reference temperature. Good.
[0011]
Further, according to the liquid crystal panel driving device of the present invention, in a liquid crystal panel driving device that performs overdrive using a frame memory and a lookup table, data is output so that a part of output data from the lookup table becomes supplementary data. The complementary data includes first complementary data and second complementary data, and a part of the previous frame data and a part of the input data are given as addresses to the look-up table. Correction using the first complementary data of the complementary data portion and the address non-use portion of the input data and the complementary process using the second complementary data and the address non-use portion of the previous frame data in the output data from Data for the correction and the non-complementary data from the look-up table. Characterized in that it is configured to generate data to be overdriven based on the data portion.
[0012]
With the configuration described above, the memory capacity of the lookup table can be reduced by reducing the address of the lookup table. Then, by including the first complement data and the second complement data in the supplement data section, more appropriate output data can be obtained.
[0013]
It is preferable that the overdrive data at the reference temperature is generated, and a temperature correction operation corresponding to the current temperature is performed on the overdrive data at the reference temperature. According to this, the memory capacity can be reduced because it is not necessary to provide a plurality of lookup tables for each certain temperature range.
[0014]
In the configuration for performing the temperature correction calculation processing, T is the current temperature, Tm is the first parameter (T when f (T) is an intermediate value between A1 and A2), A1 is the overdrive gradation at the reference temperature, A2 Is the target gradation, p is the second parameter, and f (T) is the overdrive data after temperature correction, f (T) = (A1-A2) / (1+ (T / Tm) p) + A2 To perform the temperature correction calculation process. Also, p can be any number.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0016]
In the liquid crystal panel driving device having the configuration shown in FIG. 3, 8-bit input data (target data) is input to the frame memory 1 and held. This input data is output after one frame period. That is, when input data is given this time, data one frame before (hereinafter, referred to as previous frame data) is read from the frame memory 1. The upper 4 bits of the previous frame data and the upper 4 bits of the input data are given to the look-up table (LUT) 3 as addresses.
[0017]
The look-up table 3 has 10-bit data for each address, and the lower 5 bits form complementary data. The complement data includes first complement data (a coefficient for complement on the start gradation side) and second complement data (a slope value for complement on the target gradation side). Also, of the 10-bit data, 8 bits obtained by adding 3 bits of “000” to the lower 5 bits of the upper 5 bits become overdrive data (lookup table output data) before the complement processing. Since the upper 4 bits of the previous frame data (start gradation) and the upper 4 bits of the input data (target gradation) are input to the look-up table 3 as addresses, the start gradation is discrete 0, 16, 32. ,... And the target gradation also takes discrete values such as 0, 16, 32,.
[0018]
FIG. 4A shows a part of data stored in a normal lookup table. In FIG. 4A, when the lower 4 bits ≧ 12, the lower 4 bits are set to 0 and 16 is added (rounded up). When the lower 4 bits <12, the lower 4 bits are set to 0 (round down). The result is shown in FIG. 4 (b). In the data of FIG. 4 (b), (data of FIG. 4 (a) -data of FIG. 4 (b)) ≧ | 8 | ). The stored contents in FIG. 4C are the upper 5 bits of the look-up table 3 (overdrive data before the complement processing).
[0019]
FIG. 5 shows a graph of the contents of FIG. 4B, and FIG. 6 shows a graph of the contents of FIG. 4C.
[0020]
The lower 4 bits of the previous frame data and the lower 4 bits of the input data are input to the first arithmetic circuit 4. The lower 5 bits (complementary data) of the lookup table 3 are also input to the first arithmetic circuit 4. The processing of the first arithmetic circuit 4 includes a complementing process on the starting gradation side and a complementing process on the target gradation side.
[Complementary processing on start gradation side]
Example) Assume that the starting gradation is 10 and the target gradation is 26.
[0021]
Here, start gradation A: upper 4 bits of start gradation
Target gradation B: upper 4 bits of target gradation
Start gradation C: upper 4 bits of start gradation +16
And Then, ODV [A, B] is defined as the pre-complementary overdrive data of the start gradation A and the target gradation B. The coefficient (first complementary data) K is obtained by K = (ODV [A, B] −ODV [C, B]) ÷ 16. In the above numerical example, K = (32−16) ÷ 16 = 1. Become. This “1” is stored in advance in the lower bits of the lookup table 3 as a coefficient (first complementary data).
[0022]
In the complementing process on the starting gradation side, a process of ODV [A, B] −K × (starting gradation−A) is performed. The above (starting tone-A) corresponds to the value of the lower 4 bits of the previous frame data. In the above numerical example, ODV [A, B] −K × (starting tone−A) = 32−1 × (10−0) = 22. This value is referred to as a complement value X. FIG. 7 shows a graph of this processing.
[Target gradation side complement processing]
Example) Assume that the starting gradation is 10 and the target gradation is 26.
[0023]
In the above numerical example, 3.0 is given as the gradient (second complementary data) based on the lower 5 bits of the lookup table 3. The output value A1 of the first arithmetic circuit 4 is A1 = (slope × lower 4 bits of target gradation) + complementary value X. In the above numerical example, the output value A1 = 3.0 × 10 + 22 = 52. FIG. 8 shows a graph of this processing. FIG. 9 further shows the coefficients added.
[0024]
The output value A1 of the first arithmetic circuit 4 is provided to the second arithmetic circuit 5. The second arithmetic circuit 5 is a circuit that performs a temperature correction operation on the output value A1. Here, the output value A1 of the first arithmetic circuit 4 is data corresponding to a panel temperature of 0 ° C.
[0025]
T is the current temperature (detected by the liquid crystal panel temperature sensor), Tm is the first parameter (T when f (T) is an intermediate value between A1 and A2), and A1 is the panel temperature of 0 ° C. (minimum temperature). When the overdrive gradation (output value A1 of the second arithmetic circuit 5), A2 is a target gradation, p is a second parameter, and f (T) is overdrive data after temperature correction, f (T) = ( A1−A2) / (1+ (T / Tm) p) + A2 is used to perform a temperature correction calculation process.
[0026]
FIG. 10A shows ideal overdrive values at each temperature when the start gradation is 0 and the end gradation is 128. FIG. 3B shows values obtained by the temperature correction calculation for each temperature when p = 1 and Tm = 51.
[0027]
FIG. 11A shows ideal overdrive values at respective temperatures when the start gradation is 0 and the end gradation is 16. FIG. 4B shows values obtained by the temperature correction calculation for each temperature when p = 1 or p = 2, Tm = 1 or Tm = 6, Tm = 12 or Tm = 25. ing. FIGS. 12A and 12B show graphs of the numerical values in FIG. In this calculation, a result was obtained in which p = 1 and Tm = 6 were close to the ideal values.
[0028]
FIG. 13A shows ideal overdrive values at respective temperatures when the start gradation is 224 and the end gradation is 176. FIG. 4B shows values obtained by the temperature correction calculation for each temperature when p = 1 or p = 2, Tm = 1 or Tm = 7, Tm = 12 or Tm = 25. ing. FIGS. 14A and 14B show graphs of the numerical values in FIG. In this calculation, the result that p = 1 and Tm = 7 was close to the ideal value was obtained.
[0029]
In the above description, the case where p = 1 or 2 is illustrated, but the present invention is not limited to this, and p can be an arbitrary number (natural number).
[0030]
Since the contents of the operations in the first operation circuit 4 and the second operation circuit 5 can be various, the operation circuits that realize the contents of the operation can be various. However, the present invention is not limited to the above. In the above example, the upper 5 bits of the 10 bits of the lookup table 3 are stored as LUT data, and the lower 5 bits are stored as complementary data. However, the present invention is not limited to this. The first complementary data and the second complementary data in the complementary data may exist, for example, in such a manner that the lower 5 bits are divided, or the first complementary data and the second complementary data are combined and embedded using the entire lower 5 bits. It may be in a form.
[0031]
【The invention's effect】
As described above, according to the liquid crystal panel driving apparatus of the present invention, it is possible to optimize output data (overdrive data) while reducing the amount of memory of a look-up table, and improve the image display quality of the liquid crystal panel. It has the effect of being able to increase.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an outline of an overdrive.
FIG. 2 is a block diagram showing a conventional liquid crystal panel driving device.
FIG. 3 is an explanatory diagram showing a liquid crystal panel driving device according to an embodiment of the present invention.
FIGS. 4A to 4C are views for explaining the creation of a lookup table.
FIG. 5 is a graph of FIG. 4 (b).
FIG. 6 is a graph of FIG. 4 (c).
FIG. 7 is an explanatory diagram in which correction by a coefficient is graphed.
FIG. 8 is an explanatory diagram showing a graph of correction by inclination.
FIG. 9 is an explanatory diagram in which coefficients are added in FIG.
FIG. 10A is an explanatory diagram showing ideal overdrive values at respective temperatures when the starting gradation is 0, and FIG. 10B is a diagram showing p = 1 and Tm = 51. FIG. 4 is an explanatory diagram showing values obtained by a temperature correction calculation when “1” is set.
FIG. 11A is an explanatory diagram showing ideal overdrive values at respective temperatures when the starting gradation is 0 and the ending gradation is 16; FIG. FIG. 4 is an explanatory diagram showing values obtained by a temperature correction operation when = 1 or p = 2, Tm = 1, Tm = 6, Tm = 12, or Tm = 25.
FIGS. 12A and 12B are explanatory diagrams in which the numerical values of FIG. 11B are graphed.
FIG. 13A is an explanatory diagram showing ideal overdrive values at respective temperatures when the starting gradation is 224 and the ending gradation is 176, and FIG. FIG. 4 is an explanatory diagram showing values obtained by temperature correction calculation when = 1 or p = 2, Tm = 1 or Tm = 7, Tm = 12, or Tm = 25.
FIGS. 14 (a) and 14 (b) are explanatory diagrams in which the numerical values of FIG. 13 (b) are graphed.
[Explanation of symbols]
1 frame memory 3 look-up table 4 first operation circuit 5 second operation circuit

Claims (7)

In a liquid crystal panel driving device that performs overdrive using a frame memory and a lookup table, T is a current temperature, Tm is a first parameter (T when f (T) is an intermediate value between A1 and A2), A1 Is the overdrive gradation at the reference temperature stored in the lookup table, A2 is the target gradation, p is the second parameter, and f (T) is the temperature-corrected overdrive data.
f (T) = (A1-A2) / (1+ (T / Tm) p) + A2
A liquid crystal panel drive device configured to perform a temperature correction calculation process by the following calculation expression. In a liquid crystal panel driving device that performs overdrive using a frame memory and a look-up table, data is set so that a part of output data from the look-up table becomes complementary data, and a part of the previous frame data. And a part of the input data as an address to a look-up table, generate correction data using a complementary data portion in output data from the look-up table, and generate the correction data and the correction data from the look-up table. It is configured to generate data to be overdrive at the reference temperature based on the non-complementary data portion and to perform a temperature correction calculation process corresponding to the current temperature based on the overdrive data at the reference temperature. Characteristic liquid crystal panel drive. 3. The liquid crystal panel driving device according to claim 2, wherein correction data is generated by a complementary data portion in the output data from the lookup table, an address non-use portion of the input data, and an address non-use portion of the previous frame data. Based on the correction data and the non-complementary data portion from the look-up table, generate overdrive data at the reference temperature, and generate a temperature corresponding to the current temperature with respect to the overdrive data at the reference temperature. A liquid crystal panel driving device configured to perform a correction calculation process. In a liquid crystal panel driving device that performs overdrive using a frame memory and a look-up table, data is set so that a part of output data from the look-up table becomes complementary data, and the complementary data is a first data. A part of the preceding frame data and a part of the input data are provided to the look-up table as addresses, and the first part of the complementary data part in the output data from the look-up table is provided. Compensation data is generated by a complementing process using complementary data and an address non-use portion of the input data, and a complementing process using second complement data and an address non-use portion of the previous frame data. Overdrive is performed based on the non-complementary data part from the lookup table. The liquid crystal panel driving apparatus characterized by being configured to generate data. 5. The liquid crystal panel driving device according to claim 4, wherein data to be overdriven at the reference temperature is generated, and a temperature correction operation process corresponding to the current temperature is performed on the overdrive data at the reference temperature. A liquid crystal panel driving device characterized by being performed. 6. The liquid crystal panel driving device according to claim 2, wherein T is a current temperature, and Tm is a first parameter (f (T) when T (f) is an intermediate value between A1 and A2). ), Where A1 is the overdrive gradation at the reference temperature, A2 is the target gradation, p is the second parameter, and f (T) is the temperature-corrected overdrive data.
f (T) = (A1-A2) / (1+ (T / Tm) p) + A2
A liquid crystal panel drive device configured to perform a temperature correction calculation process by the following calculation expression. 7. The liquid crystal panel driving device according to claim 1, wherein p is an arbitrary number.

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