| 摘要 |
PURPOSE:To improve the information read capability and the light utilization efficiency by correcting a light emitting pattern of a light emitting body from an elliptic type into a circular type so as to be made incident in an optical disk. CONSTITUTION:Two cylindrical lenses 3, 4 to correct the light emitting pattern of a laser light irradiated from the semiconductor laser 1 from an elliptic type into a circular type are provided on the optical path from the semiconductor laser 1 to the optical disk 2. Thus, the light emitting pattern is corrected into the circular type by the two cylindrical lenses 3, 4. The light emitting pattern of the laser light is corrected by using the two cylindrical lenses 3, 4 because an astigmatism is caused in the laser light if one single cylindrical lens is used for the correction and the shape of the incident light on the optical disk is elliptic and the reading capability of the information is made deteriorated, and the astigmatism caused by the cylindrical lens 3 is corrected by using the cylindrical lens 4. |
