| 摘要 |
PURPOSE:To obtain an optical information reader having a short manufacturing process with simple constitution by constituting a deflected beam splitter of a dielectric multi-layer film formed on a flat substrate. CONSTITUTION:An antireflection film 32 is formed on the rear side of a glass substrate 31 which is optically polished. While a dielectric multi-layer film 33 is formed on the upper surface side of the substrate 31. A long waveform pass filter is advantageous for the film 33 of a deflected beam splitter. An optimum incident angle is set at 69 deg. for the laser light 34 of said beam splitter. The function of a deflected beam splitter is attained when an incident angle is set in a range between 60 deg. and 70 deg.. Thus it is possible to obtain an optical information reader having simple constitution and a short manufacturing process with high reliability by means of a flat plate type beam splitter. |
