Optical information reader

Abstract

Abstract PURPOSE:To accurately read the information with simple and inexpensive constitution by providing two hologram lenses on a transparent base, radiating the light via one lens and receiving a reflected light through the other lens. CONSTITUTION:The divergent beam from a semiconductor laser 12 passes through a transparent base 13 and is led to the hologram 16, where the astigmatism is corrected and the result is radiated onto a recording medium 18. Then the reflected light radiated onto the medium 18 is made incident on the hologram lens 17 and the astigmatism or coma aberration is corrected by the lens 17 and converged and the light transmitted through the base 13 and the translucent mirror 15 is received by a photodetector 20 and the information signal is detected from the output of the detector 20. Thus, the information is always read accurately without causing the astigmatism or coma aberration due to oblique incidence of the read light to the recording medium with simple and inexpensive constitution.

Inventors

• 👤 Kunio Yamamiya

Bibliographic Details