The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 12, 2006
Filed:
Oct. 10, 2002
Hitoshi Furuhata, Saitama-ken, JP;
Tomotaka Nishimura, Saitama-ken, JP;
Hirokatsu Nagatake, Saitama-ken, JP;
Akira Miura, Saitama-ken, JP;
Hitoshi Furuhata, Saitama-ken, JP;
Tomotaka Nishimura, Saitama-ken, JP;
Hirokatsu Nagatake, Saitama-ken, JP;
Akira Miura, Saitama-ken, JP;
Pioneer Corporation, Tokyo, JP;
Abstract
An optical pickup which appropriately detects reflected light and return light reflected back from an information recording medium even if a laser light Bemitted from a light source varies in wavelength. The transmittances of a half mirror to the laser light Bemitted from the light source, and to the reflected light Bwr, Ber or the return light Brr reflected back from the information recording medium are preset according to a predetermined condition, i.e., Tpc(λc)/Tp(λ)=(1−Ts(λ)/(1−Tsc(λc))×(Tsc(λc)/Ts(λ)). Here, λ is a predetermined wavelength emitted from a semiconductor laser as the light source, Ts(λ) is a transmittance to the laser light Bwith a predetermined polarization, Tp(λ) is a transmittance to the reflected light Bwr, Ber or the return light Brr reflected back from the information recording medium when the laser light Bwith the predetermined wavelength λ is emitted, Tsc(λc) is a transmittance to the laser light Bwith a wavelength λc when the semiconductor laser varies in wavelength characteristic, and Tpc(λc) is a transmittance to the reflected light Bwr, Ber or the return light Brr reflected back from the information recording medium when the laser light Bwith the wavelength λc is emitted.