Patent ID: 7356223
Filing Date: 2008-04-08
Classification: G02B

Abstract:
1. An optical filter element having a target wavelength range and for use with a rod lens having an end face that includes a first area and a second area, the optical filter element comprising: a first dielectric multilayer film arranged in the first area of the end face of the rod lens; and a second dielectric multilayer film arranged in at least the second area of the end face of the rod lens, wherein the second dielectric multilayer film has a reflectance of a predetermined value or less for a light beam having a wavelength in the target wavelength range, and a portion of the second dielectric multilayer film and a portion of the first dielectric multilayer film are laminated with each other; wherein the first and second dielectric multilayer films each includes a first portion; the first area is covered by a laminated structure of the first portion of the first dielectric multilayer film and the first portion of the second dielectric multilayer film; the second dielectric multilayer includes a second portion; and the second area is covered only by the second portion of the second dielectric multilayer film.