Optical: systems and elements – Holographic system or element – Using a hologram as an optical element
Patent
1997-04-23
1999-08-17
Spyrou, Cassandra
Optical: systems and elements
Holographic system or element
Using a hologram as an optical element
359 18, 359 30, G02B 532
Patent
active
059401958
ABSTRACT:
A high-resolution light-beam scanning apparatus utilizing only mass-producible holograms instead of utilizing auxiliary optical systems such as optical lenses or a mirror having curvature, and capable of compensating for disadvantages including scanning beam thickening and variation, failure of a rotatable hologram to rotate at a constant velocity, displacement of a scanning beam position in the scanning direction and the cross scanning direction due to a mode hop of a wavelength of a semiconductor laser, and deviation of a base of rotatable hologram from a parallel state. These disadvantages are detrimental to efforts for increasing the resolution of a hologram scanner and lowering the cost thereof. The light beam scanning apparatus includes at least two holograms with an optical path length difference .DELTA..PHI. along a scanning beam light flux. The path length is measured from a light source to a scanning surface in the first hologram, and is represented by .DELTA..PHI.<C(.lambda..sup.2 /D.lambda.) where C is a constant less than 0.5. The path length is related per the above equation to a wavelength, .lambda., at the center of the light source, and a wavelength displacement .DELTA..lambda. measured from the wavelength .lambda. at the center of the light surface.
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Hasegawa Shin-ya
Nakashima Masato
Yamagishi Fumio
Chang Audrey
Fujitsu Limited
Spyrou Cassandra
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