| 摘要 |
PURPOSE:To make the optical information reader small-size, by reflecting the beam, which is reflected from the information carrier and permeates the object system and is branched by the beam splitter, by a reflective mirror and by causing this reflection beam to permeate the beam splitter again to cause it to be incident to a radiation detector. CONSTITUTION:When the light emitted from the semiconductor laser has the electric field direction deflected in the direction horizontal to the paper surface, almost all the light quantity permeates polarizing beam splitter 5, and a round polarized light is obtained by 1/4 wavelength plate 10. This polarized light is reflected by information carrier 4 and permeates object system 3 again and permeates 1/4 wavelength plate 10 and becomes a linear polarized light whose polarization direction is vertical to the paper surface. The light beam is full-reflected by polarization beam splitter 5 and permeates another 1/4 wavelength plate 10 and becomes a round polarized light and is reflected by the reflective mirror. The light beam permeates 1/4 wavelength plate 11 again and has the polarization direction parallel with the paper surface and permeates polarization beam splitter 5 and is incident to a radiation detector. |
