Patent attributes
In an optical angle detection apparatus, a single optical distance measurement unit is disposed opposite an object having a plane. The optical distance measurement unit includes a light projecting portion that projects a beam in the direction of an optical axis, and a light receiving portion that receives a beam reflected from a measurement position at which the optical axis intersects the plane and outputs a distance measurement signal indicating a distance to the measurement position. An optical axis deflector is provided for deflecting the optical axis to switch the measurement position between a first measurement position and a second measurement position, so that first and second distance measurement signals corresponding to the first and second measurement positions are output from the optical distance measurement unit. A controller obtains respective distances to the first and second measurement positions based on the first and second distance measurement signals and calculates a tilt angle of the plane based on the obtained distances.