US Patent 7283222 Optical measuring device

An optical measuring device according to the present invention includes: a plane mirror (3), which has a central opening that functions as either a light entering window or a light source fitting hole (5) and an observation window 6′ that enables a photodetector (6) to take measurements; and an integrating hemisphere (2), which has its center of radius of curvature defined within the central opening of the plane mirror (3) and of which the inner wall surface functions as a light diffuse reflective surface (1). The plane mirror (3) and the integrating hemisphere (2) form an integrating space inside.