JP2005004964A5 - - Google Patents

Claims (13)

A plurality of coherent light sources that are mounted on the same submount and emit light beams having different wavelengths (λ ₁ <λ ₂ <...), Respectively, and all the light beams having different wavelengths are converted into parallel light. An optical pickup with one collimating lens ,
The optical pickup according to claim ₁ , wherein the collimating lens is arranged such that a light beam emitted from the coherent light source that emits the light beam having the shortest wavelength λ ₁ is positioned on an optical axis of the collimating lens . A plurality of coherent light sources that are mounted on the same submount and emit light beams having different wavelengths (λ ₁ <λ ₂ <...), Respectively, and all the light beams having different wavelengths are converted into parallel light. An optical pickup with one collimating lens,
The optical pickup characterized in that the plurality of coherent light sources are arranged so that their emission end face positions are different in the optical axis direction. Among the plurality of coherent light sources, the shortest wavelength λ ₁  The optical pickup according to claim 2, wherein an emission end face position of the coherent light source that emits the light beam is shifted toward an emission direction with respect to another coherent light source. The shortest wavelength λ ₁  The optical pickup according to claim 3, wherein the coherent light source that emits the light beam is a GaN blue semiconductor laser. The plurality of coherent light sources are three coherent light sources that respectively emit light beams having different wavelengths (λ ₁ <λ ₂ <λ ₃ ), and the wavelengths of the three coherent light sources are 370 nm <λ ₁ <430 nm and 635 nm, respectively. The optical pickup according to claim 1 or 2 , wherein <λ ₂ <690 nm and 760 nm <λ ₃ <810 nm. A variable phase plate divided into concentric circular regions and inserted in an optical path between the coherent light source and the optical disc, and the light beam of each wavelength emitted from each of the coherent light sources is condensed on the optical disc. further comprising optical pickup according to claim 1 or 2 spherical aberration generated in the objective lens by the variable phase plate can be compensated for and an objective lens. Three semiconductor laser chips mounted on the same submount and emitting light beams having different wavelengths (λ ₁ <λ ₂ <λ ₃ ), respectively,
The multi-wavelength semiconductor laser unit, wherein the semiconductor laser chip that emits the light beam having the shortest wavelength λ ₁ is located in the center of the three semiconductor laser chips. The shortest wavelength λ ₁  8. The multiwavelength semiconductor laser unit according to claim 7, wherein the semiconductor laser chip that emits the light beam is a GaN blue semiconductor laser. A plurality of semiconductor laser chips that are mounted on the same submount and emit light beams having different wavelengths (λ ₁ <λ ₂ <...), Respectively,
The multi-wavelength semiconductor laser unit, wherein the plurality of semiconductor laser chips are arranged such that their emission end face positions are different in the optical axis direction. Among the plurality of semiconductor laser chips, the shortest wavelength λ ₁  The multi-wavelength semiconductor laser unit according to claim 9, wherein the emission end face position of the semiconductor laser chip that emits the light beam is shifted toward the emission direction with respect to the other semiconductor laser chips. The shortest wavelength λ ₁  The multi-wavelength semiconductor laser unit according to claim 10, wherein the semiconductor laser chip that emits the light beam is a GaN blue semiconductor laser. The multi-wavelength semiconductor laser unit according to claim 7 or 9 , wherein at least one of the plurality of semiconductor laser chips includes a semiconductor laser and a wavelength conversion element. Emitting the light beams from a plurality of coherent light sources mounted on the same submount and emitting light beams having different wavelengths (λ ₁ <λ ₂ <...), Respectively, and the light beams by a collimating lens. Converting into parallel light,
The collimating lens is arranged such that a light beam emitted from the coherent light source that emits the light beam having the shortest wavelength λ ₁ is positioned on an optical axis of the collimating lens. Playback method.