Patent ID: 7499229

Claim:
A fixing method of fixing an optical element made of plastic, which has an optically functional surface and a periphery around the optical element, and is used within a prescribed working wavelength range in a wavelength region including at least blue light and ultraviolet light, by bonding the periphery to another member with a light-hardening type of adhesive comprising the steps of: supplying the light-hardening type of adhesive to bonding spots between the periphery and the another member; and irradiating a processing light beam onto the bonding spots to harden the light-hardening type of adhesive, wherein the processing light beam has a first emission peak having a first illumination intensity in a first wavelength range from 350 to 450 nm; and wherein the processing light beam has a second emission peak in the specific wavelength range from 280 to 330 nm, which has an illumination intensity less than or equal to 30% of the first illumination intensity of the first emission peak.