| 摘要 |
PURPOSE:To improve S/N and responsiveness by constituting a light receiving system with a condensing means which condenses reflected light and a light receiving part which receives the light condensed by the condensing means. CONSTITUTION:The light emitted from a lens 2 passes a compensating plate 10 and goes toward an optical disk 20 and reaches pits 24 through a substrate 21 of the optical disk 20. The light reflected on pits 24 passes the substrate 21 and the compensating plate 10 and is made incident on a lens 3 on a substrate 1 and is condensed and is received by a light receiving part 3. Aberrations due to the projected light and the reflected light based on the difference in refractive index between air and the substrate 21 are almost solved. The reflected light from the optical disk 20 is condensed by the lens 3, and the condensed light is received by the light receiving part 4. Thus, one or plural photodetectors constituting the light receiving part 4 are made small in size to improve the S/N and responsiveness of a light reception signal. |
