| 摘要 |
PURPOSE:To obtain the titled device having an optical system wherein the diameter of a light spot is small, light intensity is large, and wavelength can be varied over a wide range at a high speed and in continuance by a method wherein the wavelength of a transmitted light is varied by rotating filters of different transmission wavelengths along the direction of the periphery. CONSTITUTION:The filter 7 is disk-formed and consists of a transparent dielectric film 9 whose thickness becomes gradually large along the circumferential direction and a doughnut-like semi-transparent metallic thin film 10 which sandwiches the outer periphery of said film. Therefore, the wavelength of the light transmitted through the outer periphery of the filter 7 also varies with the change of the center angle theta (thetaa-360 deg.). Besides, a cutout 11 to transmit the light as it is without the variation of the wavelength is formed in the filter 7 at the part corresponding to the center angle thetaa. In the titled device, the above-mentioned filters 7a and 7b wherein the ranges of the wavelength of the transmitted light are different and the ranges of the transmission wavelength of both are continuous are rotated by means of motors 8a and 8b. |
