摘要 |
A band limiter comprises an optical filter, which has first and second filter sections, and a filter moving mechanism for moving the optical filter. The first filter section reduces intensity of blue light, which is emitted from a B-LED, in a wavelength range of greater than or equal to a peak wavelength of the blue light to generate first blue light. The second filter section reduces intensity of the blue light in a wavelength range of less than or equal to the peak wavelength of the blue light to generate second blue light. A light source controller places the first filter section in a light path of the blue light in a normal mode to generate the first blue light, and places the second filter section in the light path of the blue light in an oxygen saturation mode to generate the second blue light. |