Patent ID: 7566874

Claim:
An infrared sensor comprising: an infrared sensor element; a package arranged to be surface mounted and having a substantially box shaped configuration with an opening formed at a surface, the package being configured to accommodate the infrared sensor element therein; and an optical filter configured to transmit infrared radiation with a predetermined wavelength, the optical filter being arranged to cover the opening of the package, a peripheral portion of the optical filter being joined to a circumferential region of the opening of the package by an adhesive, the optical filter being arranged to allow the infrared sensor element to receive the infrared radiation with the predetermined wavelength and to define a cover sealing the opening; wherein a plurality of grooves are located at the peripheral portion of the optical filter in a region opposed to the circumferential region of the opening of the package so as to be continuously located in the peripheral portion of the optical filter; the optical filter is disposed on an uppermost surface of the package; and an end of at least one of the plurality of grooves extends to and is exposed at an edge of the optical filter.