Limited reflection type photoelectric sensor

摘要

To provide a limited reflection type photoelectric sensor capable of extending a detection range so as to allow detection of an object, a distance from which to the surface to be measured varies, with accuracy in a simple configuration. The limited reflection type photoelectric sensor includes a light projecting unit having a laser diode and a light receiving unit having a photodiode. In the light projecting unit and the light receiving unit, an intersecting angle between an optical axis of a projected light beam and an optical axis of a receiving light beam is set such that the projected light beam from the light projecting unit is directed to an object detection limited area and the receiving light beam which is reflected light from an object existing in the object detection limited area is received by the light receiving unit. Presence/absence of the object is determined based on a light receiving level of the photodiode. A diffracting grating configured to a projected light beam into beams oriented in a plurality of directions is provided in an optical path of the projected light beam from the laser diode.