PURPOSE: To make it possible not only to measure the moving speeds of matter in many directions but also to detect the moving direction thereof, by providing a lens array wherein a plurality of convex lens bodies are arranged two-dimensionally and a light receiving array consisting of plural pairs of light receiving elements.
CONSTITUTION: A condensing lens 7 allows the light transmitted through a lens array 6 to condense to two spaces bordered by an optical axis Z. When a light source is driven to apply dark field illumination to moving matter upon looking from a light receiving system 3, the spot image of the detected visual field of the matter 1 is formed on the surface of the array 6. This spot image moves on the surface of the array 1 with the movement of the matter 1. The light passing through the array 6 is deflected positively and negatively corresponding to the movement of the matter 1 and said deflection is repeated in the number of times corresponding to the number of convex lens bodies 10 of the array 6. The transmitted light of the arrays 6 is received by the arbitrary light receiving element PD of a light receiving element array 8 positioned within the max. deflection angle. By this method, the cyclical signal corresponding to the interval between the convex lens bodies of the array 6 is obtained in the output of the light receiving element PD. By this constitution, the moving speed and direction of the matter can be measured.
MORISHITA KOJI
YOSHIDA TOMIYOSHI
KITAJIMA HIROSHI
