Apparatus for stabilizing beam for exposure
AssigneesDainippon Screen Seizo Kabushiki Kaisha, Ushio Electric Inc.
InventorsTaro Yamazaki, Kazuhiko Ohnishi, Kiyoshi Maeda
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Abstract
An apparatus for stabilizing a laser beam to be used for exposure in an image-reproducing apparatus wherein said beam is suitably controlled by image signals obtained from the scanning of the original beam as modulated. A laser beam, after being suitably modulated by an ultrasonic light modulator, is branched out by a half mirror into two beams, one of which is to be used for exposing a photosensitive material and the other is used as a negative feedback signal. This feedback signal is then added to an image signal so that a linearity between exposing beam and image signals are greatly improved. Further, by improving the linearity of exposing beam, the stability of the exposing beam is simultaneously improved.
Claims4
An apparatus for stabilizing beam to be used for exposure in an image-reproducing apparatus wherein said beam is controlled by image signals obtained from the scanning of a color original, said apparatus comprising;
- a. a laser beam source,
- b. an ultrasonic light modulator adapted to modulate laser beam emitted from said laser beam source,
- c. a half mirror adapted to branch out said beam modulated by said ultrasonic light modulator into two modulated beams,
- d. a photoelectric transducer adapted to photoelectrically transduce one of said two modulated beams,
- e. a comparison amplifier adapted to compare output signals from said photoelectric transducer with said image signals,
- f. an amplitude modulator adapted to modulate the amplitude of a sine wave of required frequency by means of output signals from said comparison amplifier, and
- g. a drive circuit adapted to drive an ultrasonic vibrator attached to said ultrasonic light modulator by means of output signals from said amplitude modulator.
Dependencies are inferred from the claim text.