Optical head device, optical information device, and information processing device

Abstract

When information is recorded or reproduced on or from an optical information medium having three or more recording layers using blue light, interference by another layer light is reduced and, when information is reproduced from an optical information medium using red light, an S/N ratio is held excellently high. An optical head device includes a first laser light source () which emits blue light, a second laser light source () which emits red light, an objective lens () which focuses the blue light onto a recording layer of a first optical disc () or focuses the red light onto a recording layer of a second optical disc (), a photodetector () which receives the blue light reflected by the recording layer of the first optical disc () or the red light reflected by the recording layer of the second optical disc () and outputs an electric signal in accordance with an amount of the received blue light or red light, and a wavelength selective light blocking region () which blocks a predetermined range of the blue light including an optical axis thereof to prevent the predetermined range from reaching the photodetector (), and transmits the red light.