| 摘要 |
PURPOSE:To miniaturize a device, and to reduce a cost by propagating either of a laser beam from a laser beam source to a hologram disc, or signal light from the hologram disc to an optical detector using an optical refractor. CONSTITUTION:A laser beam source 20 for scanning, a hologram disc 28 which scans the laser beam with a hologram and condenses the signal light, and an optical detector 29 which reads the signal light are provided, and either one, at least, of the laser beam from the laser beam source 20 to the hologram disc 28, or the signal light from the hologram disc 28 to the optical detector 29 is propagated using an optical refractor 6. Thereby, the cost down of a laser beam scanning device due to an additional thinning and the reduction of the number of constituting parts can be realized, and furthermore, when the laser beam is propagated from the laser beam source 20 to the hologram disc 28 using the optical refractor 6, most of the signal rays of light that pass through the hologram 28 are made incident on the optical detector 29, and a detection efficiency can be improved.
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