| 摘要 |
PROBLEM TO BE SOLVED: To prevent thermal stress from being applied to a plasma display panel, due to the appearance of a temperature difference, in the case of the concentration of picture elements having high brightness on a part of displayed image signals, regarding a plasma display device. SOLUTION: A mean value calculation part 3 removes and samples the low frequency component of an image signal, and a histogram calculation part 5 prepares a histogram for every brightness range. Furthermore, a judgement part 6 makes judgement as to whether a substantial brightness change exists, on the basis of the prepared histogram, and a control part 7 controls the brightness of an image signal, on the basis of the judgement. In this case, the histogram of the image signal is prepared for making judgement as to whether a substantial brightness gradient exists in the image signal and then controlling the brightness. Thus, the appearance of a temperature difference in a plasma display panel can be prevented without using a temperature detection means such as a thermocouple. According to this construction, a plasma display device can be lowered in cost, a drop in display quality can be prevented and a long service life can be attained. |
