OPTICAL DEVICE HAVING WAVELENGTH SELECTIVITY

摘要

PROBLEM TO BE SOLVED: To provide an optical device having wavelength selectivity which facilitates manufacture and reduces manufacturing costs. SOLUTION: The optical device 21 having wavelength selectivity is provided with a light guide plate 22 and a multilayer film filter 23 formed in the surface 22a. The multilayer film filter 23 is formed so that the film thickness is continuously changed within the surface 22a. When mixed light including light different in wavelength (plural wavelength components) is made incident diagonally within the light guide plate 22, since mixed light advances while repeating reflection between two surfaces 22a and 22b of the light guide plate, a position where mixed light is made incident on the multilayer film filter 23 is changed at a fixed deviation quantity in accordance with an incident angle. Thus, mixed light is separated into light different in wavelength component by the multilayer film filter 23. Since the optical device 21 is manufactured only by forming the multilayer film filter 23 in the surface 22a so as to continuously change in the surface, the number of working processes and the handling time are reduced.