JP6103804B2 - Video display device - Google Patents

Description

  The present invention relates to a video display apparatus in which a display element such as an LED or a fluorescent display tube is arranged as a pixel to form a screen, and in particular, the display surface is reduced by reducing variations in brightness of the display element at the time of low gradation. The present invention relates to a control technique that enables display with uniform brightness over the entire area.

  The conventional video display device has a control function for improving the video quality by making the brightness of the entire video display device from the viewing position uniform regardless of the size of the display surface. (For example, see Patent Document 1)

JP-A-9-198007

  When all the pixels are driven under the same conditions, there is a problem that the display on the screen is not uniform due to the variation in the luminous intensity of each display element, and the entire screen is visible. In order to prevent such a problem, the driving means for driving the display element obtains correction data for the display element in order to absorb variations in the luminous intensity of each light emitting element, and the optimum light emission luminance of each light emitting element. Is calculated. A conventional video display device eliminates uneven luminance as a whole and improves video quality based on correction data prepared in advance and stored in a memory.

  However, during the correction calculation, lighting data below the decimal point that cannot be expressed by light emission is discarded, so that a difference in brightness occurs due to a difference of one gradation. The variation in the luminous intensity due to this difference causes a problem that the low luminance display can be recognized more conspicuously than the variation in the luminous intensity of the light emitting element. For example, when all the display elements emit light with the same lighting data, there are a light emitting element that emits light at gradation 1 and a light emitting element that emits light at gradation 2 according to correction data of each light emitting element. This difference of one gradation is visually recognized as unevenness in dot units.

  The present invention has been made to solve the above-described problems, and improves the video display quality by using a control technology that reduces the variation in the luminous intensity of the display element for each dot at the time of low gradation. An image display device is to be obtained.

The video display device according to the present invention is used for correcting a plurality of display elements arranged and connected in a matrix, a display element driver for driving these display elements, and variations in luminous intensity for each pixel of the display elements. A display panel having a nonvolatile memory for storing correction data, and a display module having a control unit for controlling the display element, the display element driver, and the nonvolatile memory are arranged and connected in a matrix. In the video display device configured as described above, when the control unit performs the variation correction of the light emission intensity of each dot of the display element by controlling the fluctuation of the light emission intensity of the display element of each dot by a correction calculation, when at least one of the video signal data to is low gradation, the correction data of said nonvolatile memory Instead of using, by using the average value of the correction data stored in all the non-volatile memory of the display module having a display element of the low gradation, and performs correction for the display device of the low gradation.

  According to the present invention, it is possible to reduce variations in the luminous intensity of the display element for each dot when displaying a low gradation image.

1 is a configuration diagram of a video display apparatus according to Embodiment 1 of the present invention. It is an example of correction value data of the display elements 1 to 9 according to the first embodiment of the present invention. It is an example of the calculation result and drive data value of correction | amendment calculation control of the gradation 100.7 of the video signal data based on the correction value data of FIG. It is an example of the calculation result and drive data value of correction | amendment calculation control of the gradation 1.9 of the video signal data based on the correction value data of FIG. FIG. 5 is an example of display unevenness in dot units based on the data of FIG. 4. FIG. It is an example of the calculation result and drive data value of correction | amendment calculation control of the gradation 1.9 of the video signal data which concern on Embodiment 1 of this invention.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a video display apparatus according to Embodiment 1 of the present invention. The video display apparatus 1 is configured by arranging and connecting a plurality of display modules 2 in a matrix, and the display module 2 is A plurality of display panels 3 are arranged and connected in a matrix and configured with the control unit 7. The display panel 3 is configured by arranging and connecting a plurality of display elements 4 in a matrix, and constitutes an image display surface. The display panel 3 includes a display element 4 composed of a plurality of (for example, 16 dots × 16 dots) LEDs and light emitting display elements (pixels) such as a fluorescent display tube, a display element driver 5 for driving the display element 4, and A non-volatile memory 6 is provided for storing correction data used for correcting variations in luminous intensity for each pixel of the display element 4. The correction data has a data amount corresponding to the number of pixels (for example, 16 dots × 16 dots) included in each display panel 3.

  The control unit 7 includes a microcomputer 8, a correction value memory 9, a video memory 10, and an arithmetic controller 11. In response to a command from the host, the microcomputer 8 performs overall control of the display function in the display module 2 and communication control such as transmission and reception of correction data with the nonvolatile memory 6 in the display panel 3. The correction value memory 9 includes a RAM and stores correction data having a data amount corresponding to the total number of pixels in the display module 2. The correction data temporarily stored in the correction value memory 9 is data that is read from the nonvolatile memory 6 and developed by the microcomputer 8 via the arithmetic controller 11. Luminous intensity correction for absorbing variations in luminous intensity of the display element 4 is performed over all pixels, that is, all display elements. That is, all the display panels 3 have their respective nonvolatile memories, and all the correction data stored in the respective nonvolatile memories 6 are developed in the correction value memory 9.

  The video memory 10 is composed of a RAM, and from the video display device 1, that is, a host control unit in which video signal data having a data amount corresponding to the total number of pixels included in the display module 2 is arranged outside the video display device 1. The video signal data is input via the arithmetic controller 11 and temporarily stored. The arithmetic controller 11 converts the video signal data stored in the video memory 10 and the correction data stored in the correction value memory 9 into all the data on the display panel 3 in order to absorb variations in the luminous intensity of the display element 4. Calculation is performed so that the luminous intensity of the display element 4 is constant, and driver drive data for driving the display element driver 5 is generated.

An example of calculation for absorbing variation in luminous intensity will be described. For example, in an A element whose emission intensity is “a” and a B element whose emission intensity is “b”, the target intensity is “c”, the A element is 1.5 times the target, and the B element is 1/2 the target. In this case, it is necessary to carry out a correction of 1 / 1.5 for the A element, and it is necessary to carry out a double correction for the B element. Assuming that the correction value data Xa of the A element and the correction value data Xb of the B element are 10-bit (1024 maximum) operation data, and 512 is a condition of 1 time correction,
c = a × Xa / 512
c = b × Xb / 512
The calculation is performed with correction value data Xa = 341 and Xb = 1024 satisfying the above.

  Further, the arithmetic controller 11 reads out only the data for driving a desired display element from the video signal data and the correction data at a synchronized timing, and performs an operation on each of the read data. Driver drive data for driving the display element is generated and transmitted to one of the corresponding display panels 3. This read operation and calculation operation are finally performed for all the display elements 4 by sequentially advancing the memory addresses of the video memory 10 and the correction value memory 9 corresponding to the display elements 4. Thereby, display driving is performed on all display elements 4 included in all display panels 3 in the display module 2 constituting the video display device 1.

  In the present invention, in the video display device 1 configured as described above, when the video signal data is in the middle gradation level and the high gradation level, the correction data of the luminous intensity of each display element is stored in the nonvolatile memory 6 in the display panel 3. In the correction value memory 9 in the control unit 7 and the calculation control, the variation in the luminous intensity of each dot of the display element is corrected. However, when the video signal data is low gradation, By using a fixed value instead of correction value data for each display element, variation in luminous intensity of each dot due to a difference in gradation value is reduced. As the fixed value, for example, an average value of correction value data of all display elements in the correction value memory 9 is used.

  For example, when the video signal data of all the display elements is a medium gradation of 100.7, if 512 is used as the correction calculation data under the condition of 1 time correction, each display element (encircled in the figure) as shown in FIG. In the case where correction data is assigned to (number indicates an element number), the result of the correction calculation control is as shown in FIG. A value obtained by discarding the lighting data below the decimal point that cannot be expressed by light emission is used as driver drive data for driving the display element. As can be seen from FIG. 3, the maximum correction of about 8% is performed on the gradation 100.7 of the video signal data.

  However, when the video signal data has a low gradation of 1.9, and processing is performed using the same correction value data as in the middle gradation, the drive data of each display element is gradation 1 as shown in FIG. And gradation 2 lights up. The video signal data 1.9 is corrected as much as 50% at the maximum, and a difference of one gradation is visually recognized as unevenness in dot units (thick circles indicate bright elements) as shown in FIG. In order to reduce this unevenness, when the video signal data is displayed at a low gradation, the gradation value is made uniform by calculating and controlling the average of the correction value data of all the display elements as a fixed value. In the case of the correction value data as shown in FIG. 3, when the video signal data is 1.9 having a low gradation, (520 + 550 + 480 + 490 + 510 + 550 + 490 + 530 + 510) ÷ 9 = 514 is a fixed value. If this fixed value is used as the correction value data, the drive data of all the display elements becomes 1 as shown in FIG. 6, and the unevenness of the dot unit due to the difference in gradation can be reduced.

1 video display device,
2 display modules,
3 Display panel,
4 display elements,
5 Display element driver,
6 non-volatile memory,
7 Control unit,
8 Microcomputer,
9 Correction value memory,
10 video memory,
11 Arithmetic controller.

Claims (1)

A plurality of display elements arranged and connected in a matrix, a display element driver for driving these display elements, and a non-volatile memory for storing correction data used for correcting variations in luminous intensity for each pixel of the display elements And a display module including a control unit that controls the display element, the display element driver, and the nonvolatile memory, and a video display device configured by arranging and connecting in a matrix, When the control unit performs the variation correction of the light emission intensity of each dot of the display element by controlling the fluctuation of the light emission intensity of the display element of each dot by the correction calculation, at least one of the video signal data to the display element is when a low tone, instead of using the correction data in the nonvolatile memory, the display of low gradation Using the average value of the correction data stored in all the non-volatile memory of the display module with a child, an image display device which is characterized in that a correction for the display device of the low gradation.

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