Image exposure device and laser exposure device applied thereto
AssigneeFuji Photo Film Co., Ltd.
InventorsKenji Matsumoto, Toshiro Hayakawa, Yoshinori Morimoto, Kiichi Kato
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Abstract
When a ratio R between a total angle φ of a widening angle in a median intensity of light of a light source (a GaN based semiconductor laser) and a total angle 2/φ of a widening angle of light defining a numerical aperture NA of a collimator optical system (collimator lens) is defined as R=(sin−1NA)×2/φ, the numerical aperture of the collimator optical system (collimator lens) is set so that 2.0≧R≧0.58. Thus, an image exposure device is provided that can suppress stray light of a light source that emits a large amount of stray light.
Claims15
An image exposure device that uses a laser beam to scan-expose an image on photosensitive material, the image exposure device comprising:
- a GaN based semiconductor laser for emitting light that includes a laser beam and emission light other than the laser beam;
- and
- a lens through which the laser light emitted from the GaN based semiconductor laser is irradiated onto the photosensitive material,
- wherein when a numerical aperture of the lens is NA, setting of the NA is conducted so that a total angle φ of a widening angle of a median intensity of the laser beam emitted from the GaN based semiconductor laser satisfies φ≧(sin−1NA)×2.
An image exposure device that uses a laser beam to scan-expose an image on photosensitive material, the image exposure device comprising:
- a GaN based semiconductor laser for emitting light that includes a laser beam and emission light other than the laser beam;
- a drive for driving the GaN based semiconductor laser so that the light is emitted at an amount that is equal to or greater than an amount necessary to be able to expose the photosensitive material even if the light is reduced;
- and
- a limiter for limiting the light emitted from the GaN based semiconductor laser so that the light irradiated onto the photosensitive material is of an amount necessary for exposure, the limiter being disposed in an optical path of the light that is emitted from the GaN based semiconductor laser and irradiated onto the photosensitive material.
A laser exposure device comprising:
- a semiconductor laser that comprises gallium nitride and emits stray light other than laser light when emitting laser light;
- and
- a diffraction unit for diffracting the laser light emitted from the semiconductor laser in a predetermined direction that is different from that of the stray light.
Dependencies are inferred from the claim text.