Abstract: A photoelectric sensor capable of preventing a malfunction caused by mutual interference is provided. The photoelectric sensor includes: a light projecting unit that repetitively emits a set of pulse light, which follows a projected light pattern in which a light projecting period is made different by a fixed time, as signal light; a light receiving element that receives the signal light; and a light receiving controller that distinguishes a light incident state and a light blocked state based on a received light signal from the light receiving element. The light projecting unit has a first pattern having the light projecting period increased by a fixed time and a second pattern having the light projecting period reduced by a fixed time as the projected light pattern, and in the first and second patterns, a pulse indicating a shortest period is included in the light projecting period other than the shortest period.

Abstract: A photoelectric sensor capable of preventing a malfunction caused by mutual interference is provided. The photoelectric sensor includes: a light projecting unit that repetitively emits a set of pulse light, which follows a projected light pattern in which a light projecting period is made different by a fixed time, as signal light; a light receiving element that receives the signal light; and a light receiving controller that distinguishes a light incident state and a light blocked state based on a received light signal from the light receiving element. The light projecting unit has a first pattern having the light projecting period increased by a fixed time and a second pattern having the light projecting period reduced by a fixed time as the projected light pattern, and in the first and second patterns, a pulse indicating a shortest period is included in the light projecting period other than the shortest period.

Abstract: In a distance measuring apparatus for optically detecting a distance to an object by using a triangulation method, two signals which are obtained from a position sensitive device are added and it is detected that the result of the addition has exceeded a predetermined threshold level. On the other hand, it is assumed that a signal waveform to drive a light emitting device is a signal whose level increases with an elapse of time. When the addition result exceeds the threshold level, the level of the drive signal is held constant. At this time, by dividing a signal obtained from the position sensitive device by the signal indicative of the addition result, a signal relating to the distance to the object is obtained.