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:
May. 10, 2005
Filed:
Aug. 13, 2003
Ryuichiro Goto, Yokohama, JP;
Hiroki Hotaka, Yokohama, JP;
Yoshiharu Ooi, Koriyama, JP;
Reiko Nozawa, Yokohama, JP;
Noriaki Shimodaira, Yokohama, JP;
Ryota Murakami, Koriyama, JP;
Ryuichiro Goto, Yokohama, JP;
Hiroki Hotaka, Yokohama, JP;
Yoshiharu Ooi, Koriyama, JP;
Reiko Nozawa, Yokohama, JP;
Noriaki Shimodaira, Yokohama, JP;
Ryota Murakami, Koriyama, JP;
Asahi Glass Company, Limited, Tokyo, JP;
Abstract
An optical head device having an optical element capable of transmitting without diffracting light having a wavelength emitted from a two-wavelength semiconductor laser and capable of diffracting light having another wavelength, to provide high utilization efficiency of light in a stable manner. For this purpose, a wavelength-selective diffraction elementA comprising a transparent substrate having a front surface on which a grating having a periodically recessed and projected shape in cross section is formed and a filling memberA filled in the concavo-convex portionA of the grating wherein the concavo-convex portion of the grating is provided with an organic pigment having the absorption edge of light in a region having a shorter wavelength than the wavelength λ, and the concavo-convex member and the filling member have the same refractive index with respect to either one of light having a wavelength λand light having a wavelength λ, and they have different refractive indices with respect to the other light having a wavelength, is disposed between the light source and the objective lens of the optical head device.