| 摘要 |
<p>PURPOSE:To detect the existence of an object with great accuracy even when the range of variance in light-emitting elements and photodetector elements is larger than usual, by using a compensating factor as a multiplier in the case that the individual driving quantity, required for obtaining a certain quantity of emission, becomes larger than the upper limit value or less than the lower limit value. CONSTITUTION:In order to control the values of individual light-emitting and reception Wn to a fixed value W when there is no object to interrupt the light, the light reception quantity is obtained by driving the respective corresponding light-emitting element with individual light-emitting driving electric current, where the individual light- emitting driving quantity for driving the respective light-emitting element, is in between the upper and lower limits. In the case that the individual light-emitting driving quantity is a value larger than the upper limit or smaller than the lower limit, the individual light-emitting driving current In is set at the upper limit or lower limit values, and the photodetection quantity is multiplied by a pre-calculated compensating value. Consequently, regardless of the limitation of upper and lower limit values, the photo- detection quantity from each light-emitting element when no light interruption exists is content.</p> |
