| 摘要 |
<p>PURPOSE:To properly correct quantity of light even when the light quantity characteristic of an LED array changes with an elapse of time, by setting a positions of LED elements so that the LED elements are contained in the correction range of a correction circuit in almost largest numbers. CONSTITUTION:In such a state that the position of a correction range is set to a correction circuit 21, the image signal and the correction data to the LED element corresponding to said image signal are respectively inputted from an image signal input terminal 1 and from correction ROM 3 to the correction circuit 21. Then, the correction data is added to the image signal to form a new image signal which is, in turn, inputted to a drive circuit 4. In the drive circuit 4, a power supplied from a power input terminal 6 is controlled on the basis of a signal inputted and a current is selectively applied to each LED element of an LED array 5. By this method, an arbitrary LED element is allowed to emit light for an arbitrary time on the basis of an image signal. A current is applied for a long time to a LED element of a small light emitting quantity, and is applied for a short time to the LED element of a great light emitting quantity.</p> |
