Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
2001-08-28
2004-08-31
Pham, Hai (Department: 2861)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
C347S239000
Reexamination Certificate
active
06784915
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a laser imager employing a linear reflective spatial light modulator.
2. Description of the Background Art
A Grating Light Valve™ (GLV™) is known as a reflection type spatial light modulator employed for a laser imager.
The GLV™, which is manufactured by Silicon Light Machine, CA, is constructed such that thousands of narrow reflectors (ribbons) laterally arranged in parallel with each other are activated by electric force, thereby modulating a light beam through diffraction caused by the ribbons.
When such a reflective spatial light modulator as the GLV™ is employed, a light beam applied thereto can be divided into a number of light beams to be individually modulated.
Like other spatial light modulators, the GLV™ has a glass window a small distance away from the ribbon surface. This structure may cause etalon fringes when a laser beam is applied.
SUMMARY OF THE INVENTION
The present invention is directed to a laser imager for recording an image on an image recording medium.
According to an aspect of the present invention, the laser imager comprises a) a laser light source emitting a first laser beam, b) a first optical system converting the first laser beam to a second laser beam, c) a Grating Light Valve™ comprising reflecting members and a window placed a small distance away from the reflecting members and d) a second optical system comprising a focusing lens for focusing a signal beam modulated by the light valve on the image recording medium. The first optical system comprises a bending element bending the first laser beam to convert the first beam to the second beam, and the normal to the light valve forms a nonzero angle &thgr;xz with the second beam.
In a preferred embodiment of this aspect, the first optical system further comprises a lens for leading the first beam to the bending element.
Preferably, the angle &thgr;xz should be between 4° and 20° and the bending element should comprise a total internal reflection (TIR) prism.
According to another aspect of the present invention, the laser imager comprises a) a laser light source emitting a first laser beam, b) a first optical system converting the first laser beam to a second laser beam, c) a Grating Light Valve™ comprising reflecting members and a window placed a small distance away from the reflecting members and d) a second optical system comprising a focusing lens for focusing a signal beam modulated by the light valve on the image recording medium. The second optical system comprises a bending element bending the second beam to convert the second beam to the third beam, and the normal to the light valve forms a nonzero angle &thgr;xz with the second beam.
In a preferred embodiment of this aspect, the bending element is used to bend the modulated signal beams.
According to still another aspect of the present invention, the laser imager comprises a) a laser light source emitting a laser beam and b) a Grating Light Valve™ comprising reflecting members and a window placed a small distance away from the reflecting members inclined from the first direction to modulate the light beam and c) at least one optical element arranged in the optical path for bending the optical axis of the light beam.
According to the present invention, the laser beam is applied at a desired angle &thgr;xz with respect to the GLV™, whereby interference of light can be prevented. The bending element enables the laser beam to hit the light modulator at a relatively small angle.
Accordingly, an object of the present invention is to provide a laser imager capable of preventing creation of etalon fringes on the Grating Light Valve™.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 5802034 (1998-09-01), Gelbart
patent: 5982553 (1999-11-01), Bloom et al.
patent: 6084626 (2000-07-01), Ramanujan et al.
patent: 6229650 (2001-05-01), Reznichenko et al.
patent: 2000-131628 (2000-12-01), None
Dainippon Screen Mfg. Co,. Ltd.
McDermott Will & Emery LLP
Pham Hai
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