INFRARED OPTICAL FILTER AND METHOD FOR MANUFACTURING THE SAME

PROBLEM TO BE SOLVED: To provide an infrared optical filter which has an infrared ray interrupting function in a broad band region from a near infrared ray to a far infrared ray and which is low in cost. SOLUTION: The infrared optical filter controlling infrared rays in a wavelength region of 800 to 20,000 nm includes a semiconductor substrate 1, a broad band region interrupting filter section 2 formed on one surface side of the semiconductor substrate 1 and a narrow band region transmissive filter section 3 formed on another surface side of the semiconductor substrate 1. The broad band region interrupting filter section 2 is constituted of a multilayer film formed by laminating two or more kinds of thin films 2a, 2b having different refractive indexes. One kind of thin film 2a among two or more kinds of thin films 2a, 2b is formed of a far-infrared ray absorbing material (for example Al2O3) and one residual kind of the thin film 2b is formed of a high refractive index material with a refractive index higher than that of the far-infrared ray absorbing material (for example Ge). COPYRIGHT: (C)2010,JPO&INPIT