| 摘要 |
PROBLEM TO BE SOLVED: To enable application to an optical recording/reproducing device requiring light of a short wavelength by adopting second higher harmonic generator and using an optical pickup in which continuous oscillation light of a short wavelength is obtained from light of a long wavelength emitted from a light source. SOLUTION: A wavelength of light of a long wavelength in a wavelength region of 1270-1300nm emitted from a light source 20 of an optical pickup device is changed by a non-linear signal crystal element 32 of a second higher harmonics generator 30, after it is resonated between a focus lens 31 consisting a resonator and a filter 33, light having a wavelength region, for example, 635-650nm transmits the filter 33, and image is formed on a recording medium 1 through an optical path conversion means 23 and an object lens 24. Light reflected from the recording medium 1 is passed through the object lens 24, diffracted and transmitted in the optical path conversion means 23, and formed in an optical detector 25 mounted on a mount 21. |
