Digital imaging system employing non-coherent light source

Details Digital imaging system employing non-coherent light source Digital imaging system employing non-coherent light source

2001-04-25

2004-03-02

Pham, Hai (Department: 2861)

Incremental printing of symbolic information

Light or beam marking apparatus or processes

Scan of light

C347S239000, C347S255000

Reexamination Certificate

active

06700598

ABSTRACT:

INCORPORATION BY REFERENCE
The aforementioned Provisional Application No. 60/199,532, U.S. application Ser. No. 09/505,017 for “Digital Imaging System Utilizing Modulated Broadband Light” filed Feb. 16, 2000 by F. Hull, and U.S. application Ser. No. 09/484,405 for “Digital Imaging System Utilizing Modulated Broadband Light” filed Jan. 14, 2000 by F. Hull are hereby incorporated by reference in their entirety and made a part of this application.
BACKGROUND OF THE INVENTION
The present invention relates to a high resolution digital imaging device employing a non-coherent light source that is selectively modulated to create the individual pixels of the image to be recorded. The invention is particularly useful in the graphic arts industry for exposing a variety of light-sensitizable media such as printing plates, proofing materials, relief plates and the like.
In the graphic arts industry, high resolution images are formed by exposing a light-sensitizable medium such as a printing plate with an appropriate light pattern. Traditionally, the printing plates were covered with a patterned film and exposed by broadband light to create the desired image on the plate. The broadband light was utilized at low energy levels, such that the film intermediary was required to properly expose the plate. In this use the low level of energy strikes the entire area to be exposed for a fairly long time, 10 seconds to as much as 20 minutes, depending on the consumable.
More recently, methods that do not utilize film intermediaries have been developed. Such methods include utilizing digital laser imaging at much higher levels of energy. However, such laser devices employed with these methods are quite expensive due to the relatively high costs of lasers and of the special plates that operate with the laser imaging device, and the laser devices also operate at relatively low speeds. Attempts have also been made to implement printing devices capable of utilizing a broadband, non-coherent light source, with addressing of image pixels being accomplished by reflective spatial light modulators.
These devices have proved to be impracticable, in part due to the inability of the reflective spatial light modulators to withstand the required exposure to intense ultra-violet light, which rapidly breaks down the movable micro-mirrors of ferro-electric liquid of the modulators. The alternative is to employ a very fast and expensive media. There are a few varieties of modulators such as prism-type electro-optics, piezoelectric Kerr-cell and bi-morph piezoelectric combs that are capable of withstanding such energy. These modulators, however, are all based upon a line array as opposed to an area array. There are several patents, including U.S. Pat. No. 5,033,814 issued to Brown et al., that suggest the concept of using a DC short arc lamp, condensers and reflectors to illuminate a round bundle of fibers at one end, while the opposite end of the bundle of fibers are assembled in a straight line. There are several problems with this approach including light transmission efficiency, polishing of fibers and expense.
Additionally, the ultra-violet (actinic) radiation required to expose such graphic arts media has a wavelength in the range of 330 to 430 nano-meters, which further increases costs and reduces the overall efficiency when compared to the Brown et al. patent, which was not designed to deliver large amounts of power at these wavelengths.
It would therefore be a significant improvement in the art to provide a durable, high resolution digital imaging system utilizing a non-coherent light source, operable at high speeds with conventional printing plates. The requirements of such a light would include but not be limited to, the following: a stable illumination without an appreciable flicker; a nearly instant “on”, minimizing a warm-up period; a high ratio of actinic radiation to total radiation; minimizing a “ripple” component, caused by an AC power supply, interfering with modulation; evenly distributing illumination intensity over a specific area; providing an output spot nearly matching a modulator shape to eliminate the need for large fiber arrays; and providing a smaller and more uniform divergence angle in the illumination.


REFERENCES:
patent: 3980476 (1976-09-01), Wysocki
patent: 4380373 (1983-04-01), Sprague
patent: 4389659 (1983-06-01), Sprague
patent: 4675702 (1987-06-01), Gerber
patent: 4844577 (1989-07-01), Ninnis et al.
patent: 5028939 (1991-07-01), Hornbeck et al.
patent: 5033814 (1991-07-01), Brown et al.
patent: 5049901 (1991-09-01), Gelbart
patent: 5175755 (1992-12-01), Kumakhov
patent: 5317446 (1994-05-01), Mir et al.
patent: 5317659 (1994-05-01), Lee
patent: 5438873 (1995-08-01), Wlodarczyk et al.
patent: 5459505 (1995-10-01), Ballegaard et al.
patent: 5517347 (1996-05-01), Sampsell
patent: 5579240 (1996-11-01), Buus
patent: 5781341 (1998-07-01), Lee
patent: 5844588 (1998-12-01), Anderson
patent: 5862275 (1999-01-01), Takeuchi et al.
patent: 5917986 (1999-06-01), Vanderreydt et al.
patent: 5930027 (1999-07-01), Mentzer et al.
patent: 6081316 (2000-06-01), Okamura et al.
patent: 6114807 (2000-09-01), Kavanagh
patent: 6201559 (2001-03-01), Wada et al.
patent: 2-96463 (1990-04-01), None
Vanderreydt, J.P., “Large-Area Fiber-Optic Display Using Piezoelectric Shutters”,SID 95 Digest, pp 311-314, 1995.
Li, Jun et al., “Electrooptic Wafer Beam Deflector in LiTaO3”,IEEE Photonics Technology Letters, vol. 8, No. 11, pp 1486-1488, Nov. 1996.
Chiu, Yi, “Shape-Optimized Electrooptic Beam Scanners: Analysis, Design, and Simulation”,Journal of Lightwave Technology, vol. 17, No. 1, pp 108-114, Jan. 1999.

Affiliated with

Also associated with

Rating

Digital imaging system employing non-coherent light source does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Digital imaging system employing non-coherent light source, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Digital imaging system employing non-coherent light source will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3230145