Patent ID: 7220003

Claim:
An image-projecting apparatus comprising: a projection optical system which is configured to project light from an image-forming element onto a projection surface; and a detecting system which is configured to perform a detecting operation of a distance to the projection surface or a detecting operation of a focusing state of the projection optical system with respect to the projection surface, wherein the detecting system is configured to (a) determine a condition of the detecting operation on the basis of a light-receiving intensity level of a light-receiving element which is configured to receive reflected light from the projection surface of light projected through the projection optical system, and (b) perform the detecting operation in accordance with the condition, and wherein the condition relates to a number of times of the detecting operation, and the detecting system is configured to set the number of times of the detecting operation to a minimum number of times, which can be determined by the detecting system, in a case where the light-receiving intensity level is within a predetermined range, and to set the same to a greater number of times of the detecting operation with increasing of the difference of the intensity level from the predetermined range in a case where the light-receiving intensity level is outside the predetermined range.