Video display device

A video display device is described, which is capable of easily correcting variations in luminous brightness of each display element. When a video display part is comprised of a plurality of display units including a plurality of display elements, respective correction data for correcting the variations in luminous brightness of the individual display elements are supplied to memory means. When the display elements are driven, the correction data is supplied to their corresponding drivers. In doing so, the display elements can be driven in a corrected state of the variations in luminous brightness. Even when a unit cell comprising display elements is replaced by another and brightness level is re-adjusted, new correction data relative to it is updated. Said updated correction data may simply be stored in the same memory means. Thus, the variations in luminous brightness can be easily corrected even when the unit cell is replaced by another and re-adjusted.

What is claimed is:

1. A video display device comprising a display unit including a unit cell, said unit cell comprising:

a plurality of dots arranged vertically and horizontally, each dot being comprised of a plurality of display elements;

first memory means for storing therein video data to be supplied to said display elements; and

second memory means for storing therein current correction data for correcting variations in luminous brightness of each of said display elements, thereby allowing said current correction data to be reset even when said unit cell is being replaced or readjusted;

a data read counter connected to both the first and second memory means;

wherein said display elements are driven based on the current correction data read from said second memory means.

2. The video display device according to claim 1,

wherein said dot comprises three display elements, each display element emitting light of red, green or blue.

3. The video display device according to claim 1,

wherein said display element comprises any of an organic light-emitting device, a light-emitting diode device, a discharge tube and a cathode ray tube.

4. The video display device according to claim 1,

wherein said display element is driven on the basis of current values corresponding to analog values for the correction data read from said second memory means.

5. The video display device according to claim 1,

wherein said video data to be corrected is a digital value, said video data is corrected by the correction data read from said second memory means, and each of said display elements is driven on the basis of the video data corrected.

6. The video display device according to claim 5,

wherein said video data corrected is pulse-width modulated and the time required to drive said display element is controlled on the basis of the pulse width.

7. The video display device according to claim 1,

wherein said first memory means comprises a plurality of storing means each of which stores successively the video data to be supplied to said plurality of display elements in either one-frame unit or one-field unit.

8. The video display device according to claim 7,

wherein said first memory means comprises two memories, one of which stores therein the video data corresponding to one odd-numbered frame or field and the other of which stores therein the video data corresponding to one even-numbered frame or field.

9. The video display device according to claim 1,

wherein said first memory means stores therein the video data to be supplied to said plurality of display elements in one-frame unit or one-field unit, and when said dots are divided into a plurality of dot groups, said dot groups are successively switched and driven on the basis of the video data read from said first memory means, said video data corresponding to said dot groups.

10. The video display device according to claim 9,

wherein said dot groups comprises two dot groups and said two dot groups are alternately switched and driven on the basis of video data read from said first memory means, said video data corresponding to said two dot groups.

11. The video display device according to claim 9,

wherein said dot comprises three display elements, each display element emitting light of red, green or blue; and

wherein said dot groups are comprised of display elements emitting the same light-emitting color and driven successively and simultaneously for each of said dot groups.

12. The video display device according to claim 9,

wherein said dot comprises three display elements as a unit, said elements emitting respectively light of red, green and blue; and

wherein said three display elements are successively switched and driven according to the switching of said dot groups.

13. The video display device according to claim 1,

wherein said video data is video data for a stereoscopic display.

14. The video display device according to claim 13,

wherein video data for the left eye and video data for the right eye are alternately read from the first memory means within the same frame cycle.

15. The video display device of claim 1, further comprising:

while one of said memory means is kept in write mode, the other is kept in read mode.

16. The video display device of claim 1, further comprising:

a shift register, connected to both first and second memory means;

a following comparator, connected to the shift register,

a control signal generating circuit, connected to said following comparator as well as the clock and carry pulses;

wherein the following comparator converts the video data into a compared output to be pulse-width modulated by the control signal generating circuit.

17. The video display device of claim 16, wherein said control signal generating circuit further comprises:

a first counter which receives the carry pulse and clock pulse so as to generate a synchronized counter output;

a second counter which receives a switching pulse and thereby generates a carry pulse;

a third counter which generates pulses which drive red, greed, and blue triads; and

a fourth counter which generates a pulse for switching between upper and lower dot groups.

18. The video display device of claim 16, wherein said comparator outputs a high level signal until latched video data and a count output coincide with each other, thereby producing compared outputs which differ in pulse width.

19. The video display device of claim 1, wherein said second memory means stores predetermined current correction data corresponding to a plurality of display elements, so that said data can be reset even when said unit cell is being replaced or readjusted.

20. The video display device of claim 17, further comprising:

a selector means, responsive to said fourth counter pulse, for allowing both upper and lower display elements to be alternatively driven by a single driver.