| 摘要 |
PROBLEM TO BE SOLVED: To enable a recording and reproducing device to detect inclination of a recording medium in utilizing useless light from a hologram optical element by detecting the inclination of the recording medium with a detecting result of reflected light by the recording medium. SOLUTION: A light beam from a laser diode 31 is incident on the hologram optical element 32, and ±1st order diffracted light and 0-order light are incident on a collimator lens 33. The ±1st order diffracted light from the optical element 32 is transmitted through the lens 33 and a beam splitter 34, and is deflected upward by a rising mirror 39 to irradiate the disk 36 without passing through an objective lens 35. The diffracted light reflected by the disk 36 is given via bisected detector 38 to an inclination detecting means 38a, and its difference is calculated to be converted into a signal for showing an inclination of the disk. |
