PURPOSE: To make the device simple, small-sized, and low-cost, by providing a total reflective mirror, a half mirror, and a polarizing prism as one body freely movably and using properly the total reflective mirror and the half mirror alternatively by the movement of them.
CONSTITUTION: In the recording, a polarizing prism 3 and a half mirror 4 are not used, but only a total reflective mirror 5 is used. In this case, the light from a light source 1 becomes parallel rays through a collimator lens 2 and is reflected by the reflective mirror 5 and is condensed by an object lens 6 and is projected to a recording meidum 7. In the reproducing, the light from the light source 1 is polarized linearly by the prism 3 after passing through the lens 2. The power irradiated to the medium 7 is reduced to the half by the use of the half mirror 4. The reflected light from the medium 7 passes through the lens 6, the half mirror 4, a polarizing prism 8, and a condenser lens 9 and is detected by a photodetector 10. Thus, the prism 3, the half mirror 4, and the reflective mirror 5 are moved in the part surrounded with the dotted line to realize recording and reproducing optical systems.
KAWABATA HIDEJI
ORUKAWA MASAHIRO
HARA NORIAKI
KUDOU YOSHIHIKO
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