Focus detecting device

摘要

A focus detecting device for optical devices such as cameras and microscopes, which like the human eye, can detect a point of focus in response not only to the contrast of an object but also to differences in hue. The invention provides a device which provides a measurement of contrast from an image projected onto sensors separated according to different ranges of wavelength. Focus is detected by the sensors as they measure the differences in the intensity of incident light reflected from an object under focus. The sensors also provide a measure of contrast in response to different wavelength ranges.