Optical head, optical recording and/or reproducing apparatus and integrated optical module,申请号US20050075502-传众专利搜索

Optical head, optical recording and/or reproducing apparatus and integrated optical module

申请公布号：US7072271(B2)

申请号：US20050075502

申请日期：2005.03.09

申请公布日期：2006.07.04

分类号：G11B7/00;G11B7/12;G02B27/10;G11B7/09;G11B7/125;G11B7/13;G11B7/135

主分类号：G11B7/00

摘要：An optical head includes a light emitter/detector to emit a laser light towards an optical disc and to detect a return light from the optical disc, a diffraction grating to split the laser light into three beams, and a light converging optical system to focus the laser light on a recording surface of the optical disc. The diffraction grating has formed therein a plurality of slits formed whose depth is selected so that the efficiency of diffraction of first-order light when a first light beam is incident upon the diffraction grating is higher than that when a second light beam having a longer wavelength than the first light beam is incident upon the diffraction grating.