| 摘要 |
PROBLEM TO BE SOLVED: To drastically reduce the number of electric circuits and the number of parts by arranging a polarizing beam splitter film and a quarter-wave plate in lieu of a half-mirror film so that an optical utilization efficiency becomes theoretically 100%. SOLUTION: A polarizing beam splitter 10 has optical characteristic, in that S-polarized light beams are reflected approximately 100%, and P-polarized light beams are transmitted by almost 100%. Due to these characteristics, the luminous flux emitted from a semiconductor laser 1 is reflected to an objective lens 5 side. The luminous flux reflected by the beam splitter 10 is converted into a circular polarized luminous flux, when the flux passes through a quarter- wave plate 11. After that, the flux passes though an objective lens 5, an optical card 6 and the objective lens 5 and is made incident on the plate 11. Since the flux is reflected by the card 6, the flux is polarized in the reverse direction with respect to the circular polarization direction. After passing the plate 11 again, the flux becomes a linearly polarized luminous light flux having a vibration surface in a direction rotated by 90 degrees with respect to the direction during the incident. Due to the characteristics of the flux in the vibration direction, the flux allows more than 100% to pass through. |
