Optical displacement meter

An optical displacement meter comprising:

• a projecting unit that irradiates a workpiece with slit light extending in an X direction;
• an image sensor that has a plurality of pixels two-dimensionally arrayed in a U direction corresponding to the X direction and a V direction orthogonal to the U direction, and outputs a light receiving amount distribution of reflected light from the workpiece by the plurality of pixels;
• a motor that integrally rotates the light projecting unit and the image sensor;
• a control unit that controls the motor, causes the slit light to scan in a direction orthogonal to the X direction, and exposes the image sensor while rotating the image sensor in the direction;
• and
• a rotation angle acquisition unit that acquires a reference angle corresponding to an exposure period of the image sensor,
• wherein the control unit:
• acquires a peak position in the V direction of the light receiving amount distribution acquired by accumulating charges in the plurality of pixels while rotating the image sensor during the exposure period, and
• estimates a representative angle at which the peak position is acquired based on the reference angle corresponding to the exposure period and a control condition of the image sensor or the motor, and calculates a height of the workpiece in a Z direction at the representative angle from the peak position,
• wherein the control condition of the image sensor includes at least one of a length of the exposure period or an interval of a trigger which starts the exposure period, and
• the control condition of the motor includes at least one of an angular velocity, a rotation direction, or the number of times of reciprocation of the motor.