Presstek, Inc.

Josh P Foster

John Gary Sousa

Richard A Williams

James R Moss

Mitchell C Ruda

Wayne Mueller

Thomas C Dearman

A linear array of diode laser emitters is manufactured with sufficient thermal and electronic isolation among the emitters to permit separate addressability. The emitter bar has first and second opposed surfaces and a third surface through which the emitters direct output. A first surface of the emitter bar is affixed to a &ldquo;standoff&rdquo; element that has conductive surfaces connecting each emitter to a power source; these connections are maintained after a series of spaces is formed between the emitters of the emitter bar. The second surface of the emitter bar is affixed to a heat sink to form a finished assembly.

Emitter array with individually addressable laser diodes

Individually addressable laser crystals are optically coupled to a single slab of an optical carrier that transmits substantially without distortion. The crystals are separate for thermomechanical isolation but may be closely spaced (generally on the order of 0.003 inch apart), and may originate as a single crystal cut into separate segments.

Pumped laser diode assembly with optically coupled heat sink

Pumped laser crystals for use in an imaging apparatus are designed and housed so as to minimize variation in dot size across the spectrum of duty cycles ranging generally from 1% to 100%--that is, from print densities ranging from every hundredth pixel to every consecutive pixel.

Diode-pumped system and method for producing image spots of constant size

A laser system for imaging graphic-arts constructions avoids the need to demagnify a divergent beam by using the output of a semiconductor or diode laser to optically pump a laser crystal, which itself emits laser radiation with substantially less beam divergence. A preferred implementation utilizes, as a pumping source, at least one laser device that emits in the IR, and preferably near-IR region, to image ablative or transfer-type printing members. The output of the pumping source is provided to the laser crystal via a focusing lens arrangement. The output of the laser crystal, in turn, is focused onto the surface of a recording medium to perform the imaging function. Crystal excitation and decay times are minimized by continuously maintaining the pumping source at a bias power level, which keeps the crystal at a continuous, baseline power level just short of lasing or imaging; and then selectively and intermittently increasing power to the pumping source to cause the crystal to lase (or lase at higher power) in an imagewise pattern. By selectively varying the pulse width within certain limits, it is possible to obtain image dots of different sizes while retaining a round dot shape.

Diode-pumped laser system and method

A focusing assembly includes features that allow numerical aperture to be reduced and optimized by reducing aberrations and ghost reflections and easily controlling stop size, thereby increasing depth-of-focus. The assembly includes a single, bi-aspheric focusing lens that optimizes image quality at a specific off-axis field point. Passage of excessively divergent radiation is prevented by a baffle having a sharp, flared edge that minimizes reflection. A second aperture or baffle can be included to restrict high-divergence radiation emerging from the bi-aspheric focusing lens. All interior surfaces of the focusing assembly are preferably blackened, once again to minimize internal reflections.

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Windham, NH, United States of America

Josh P Foster