| 摘要 |
<p>An optical head for recording and reproducing optical information, the optical head comprising an illumination system which irradiates three beams of light comprising 0-order diffraction light, +1-order diffraction light, and -1-order diffraction light onto an optical information recording medium (11), and a photoreceiver system (20, 21) which receives three beams of reflected light from the recording medium; the photoreceiver system being provided with an edge mirror (19) whereby, of the three beams of reflected light from the recording medium, approximately one half of the 0-order diffraction light and all of the +1-order diffraction light is received by a first photoreceiver diode (20), without being affected by the edge mirror, and the remaining approximately one half of the 0-order diffraction light and all of the -1-order diffraction light is reflected by the edge mirror and is received by a second photoreceiver diode (21); wherein a focusing control signal, a tracking control signal, and an information signal are obtained from an output from the first photoreceiver diode or the second photoreceiver diode, or from combined outputs from the first photoreceiver diode and the second photoreceiver diode.</p> |
