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:
Jun. 15, 2010
Filed:
Jun. 26, 2006
Yoshiharu Ooi, Chiyoda-ku, JP;
Hiromasa Sato, Koriyama, JP;
Tomoki Gunjima, Koriyama, JP;
Asahi Glass Company, Limited, Tokyo, JP;
Abstract
A polarizing diffraction element having a wavelength selectivity which functions as a polarizing diffraction element at a wavelength λ, and which does not function as a diffraction grating not depending on incident polarization state and shows high transmittance at a wavelength λ, and an optical head device employing the element, are provided. The polarizing diffraction element selectively diffracts or transmits incident light having two different wavelengths each containing a first circularly polarized light and a second circularly polarized light having a rotation opposite from the rotation of the first circularly polarized light, depending on wavelength and polarization state of the incident light. Then, a reflective wavelength region for at least the first circularly incident light, does not contain said two incident wavelengths.