| 摘要 |
PROBLEM TO BE SOLVED: To reduce the size and the cost of the device by recording information in a CD-R using a DVD reproducing optical system. SOLUTION: A laser chip 21 generates laser beams having a wavelength λ1. A dichroic prism 24 passes the laser beams in the vicinity of the wavelength λ1 by approximately 100% and reflects the laser beams in the vicinity of a wavelength λ2 by approximately 100%. An objective lens 27 converges the laser beams made incident from a mirror 26 onto the recording surface of optical disks 10A and 10B to a diffraction limit. Moreover, the lens 27 makes the reflected light from the disks 10A and 10B incident on the mirror 26. A photodetector 28 converts the reflected light into electric signals and outputs the signals. In a laser coupler 29, an incorporated laser chip 41 emits the laser beams having a wavelength λ2 and an incorporated photodetector converts the reflected light beams into electric signals and outputs the signals. An aperture 30 limits the diameter of the light fluxes of the laser beams. |
