To provide a characteristic evaluating device for hologram element that is constituted to evaluate the characteristics of a hologram element under the same condition as that, under which the element is actually used so that the evaluated result of the device may not be affected by the actual service condition.
This characteristic evaluating device is provided with a collimator lens 4 which receives a luminous flux from a radiant light source 1, an objective lens 6 which receives the luminous flux from the lens 4 and converges the flux onto the reflecting surface of an optical disk medium, etc., and a position control means 7 which accurately controls the position of the lens 6. This device is also provided with a focus signal and tracing signal detecting system 10 which receives a reflected luminous flux from the reflecting surface through the objective lens 6, a holding means 3 which holds the hologram element 2 to be inspected so that the element 2 may receive the reflected luminous flux from the reflecting surface through the objective lens 6 and collimator lens 4, and a photodetecting means 14 which receives the diffracted light from the element 2.
OSHIMA HISAYOSHI
TANEDA YUSUKE
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