Patent ID: 7215476

Claim:
An optical pickup comprising: a plurality of coherent light sources that are mounted on a same submount and respectively emit light beams with different wavelengths (λ 1 <λ 2 <. . . ); and one collimator lens converting all the light beams with the different wavelengths into parallel beams, wherein the collimator lens is arranged so that the light beam emitted from the coherent light source emitting the light beam with the shortest wavelength λ 1 is located on the optical axis of the collimator lens, and wherein the plurality of coherent light sources are three coherent light sources respectively emitting light beams with different wavelengths (λ 1 <λ 2 <λ 3 ), and the wavelengths of the three coherent light sources are in the ranges 370 nm <λ 1 <430 nm, 635 nm <λ 2 <690 nm and 760 nm<λ 3 <810 nm.