Laser Power Corporation

General Atomics, Inc.

United States of America As Represented by the Secretary of the Air Force

Martin Marietta Corporation

Photera Technologies, Inc.

Graham W Flint

David E Hargis

Shlomo Assa

Robert A Bergstedt

Eric B Takeuchi

Harold A Papazian

Maurice A Pessot

Ludwig G Wolfert

Stephen R Tuenge

Charles G Fink

An image projection system comprises a laser source that generates a series of periodic pulses having substantially uniform energy content, a spatial light modulator, and a modulator driver synchronized with the laser pulses so that transition intervals of the modulator elements occur in an interpulse period between first and second states of the modulator elements. Because the pulses are substantially equal in energy, and the transitions of the modulator elements occur in interpulse intervals, the collective energy delivered to any pixel in the system described herein during the period of one frame is a direct function of the number of pulses, which can be accurately controlled in a digital manner.

Digital display system using pulsed lasers

A single frequency filter for a laser, comprising a polarizer that defines a direction of polarization and one or more birefringent elements situated within the cavity with their dielectric axes offset from the direction of polarization. The ends of the birefringent elements have a finite reflectance, and may be coated for reflectance or left uncoated. In some embodiments the filter is situated in a laser cavity with a broadband gain medium, in other embodiments, the filter is situated in an external cavity. To provide tunability, a wavelength control system is coupled to the birefringent element. An embodiment is described in which the filter comprises two birefringent elements of unequal optical length along the optical axis, which advantageously reduces the voltage required to tune the frequency. To provide tunability, the first and second birefringent elements are both coupled to a wavelength control system that simultaneously controls both elements.

Tunable single frequency filter for lasers

A multi-screen laser projection system comprises a laser source that generates a plurality of laser beams, an image display control system, a plurality of modulator arms each including a light modulator; and an optical switch coupled to the image display control system and modulators. A plurality of projection optical systems are respectively arranged to project the modulated light from each modulator onto its associated screen. The optical switch is arranged to receive the plurality of beams from the laser source and switch each of the beams to one of the modulator arms in order to illuminate each modulator with a sequence of colors during each frame. During the course of a frame, each of the colors becomes incident upon the modulator. The projection system disclosed herein can provide a cost-effective, efficient true digital projection display system with high resolution and high brightness.

Multi-screen laser projection system using a shared laser source

A progressive scan architecture for displaying a two-dimensional image by alternately scanning two or more laser beams, one after the other with a time delay between adjacent beams. The beams are arranged to become incident upon a polygon scanner in a row with an approximately uniform spatial separation and an approximately equal angle between adjacent beams. The polygon scanner scans horizontally and a galvanometer-driven mirror scans vertically. Adjacent lines are progressively scanned in sequence from top to bottom, which advantageously reduces or eliminates psycho-visual effects and is tolerant of non-linearities in the vertical scanner, allowing use of a low-cost galvo mirror. Typically, the beams in the row are arranged in pairs, and only one beam from each pair will be scanning at any one time. Embodiments are described in which the duty cycle is slightly less than 50% and the laser illumination is switched between two interleaved beam scans thereby allowing a single modulator to be used for both beams which provides significant cost advantages and improves system efficiency. For full-color images, each of the beams described can incorporate separate red, green and blue (RGB) components which are individually modulated by separate red, green, and blue modulators. The system can be scaled up with one or more additional pairs of beams to improve resolution and/or increase pixel count without requiring a high-speed polygon scanner or a highly-linear galvo scanner. Furthermore, the height of each facet in the polygon mirror need be only one beam diameter and its length need only be two beam diameters, which allows the system to approach the minimum pixel size attainable, which is useful to provide high efficiency and high brightness in the image.

Laser imaging system with progressive multi-beam scan architecture

A display system includes blue, green, and red laser light sources and light shaping devices which receive the laser light from the laser light sources and shapes the light into a number of approximately identical beamlets. The beamlets are modulated individually and the modulated beamlets are combined. The combining results in an output of beamlets, each of which comprises three input beamlets of each of the colors red, green, and blue. The resultant beamlets can then be scanned onto a display screen.

Multi-beam laser scanning display system with speckle elimination

High resolution image projection system and method employing lasers

A fiber optic coupler for coupling an asymmetrical beam such as provided by a laser diode into a fiber optic cable. The coupler comprises at least one fiber optic cable having a longitudinally-formed approximately flat entrance facet and a cylindrical curved reflective surface formed on a first end. The curved reflective surface defines a line focus proximate to the entrance facet. A support structure situates the entrance facet proximate to the laser diode so that the line focus is approximately aligned with the narrow output aperture of the laser diode. The fiber optic cable may have any cross-section, such as circular, rectangular, or square. The fiber optic cable also includes a main body for receiving and transmitting the coupled laser radiation, and an output end having an approximately flat exit facet for outputting the laser radiation. The coupler is particularly useful for coupling multiple output beams from a laser diode array into a plurality of fibers that are collected on their output ends to approximate a single beam, which can be then applied to end-pump a solid state laser.

Side injection fiber optic coupler

A fiber optic coupler for coupling an asymmetrical beam such as provided by a laser diode into a fiber optic cable. The coupler comprises at least one fiber optic cable having a first end including a tapered section that has an approximately flat coupling facet for receiving the asymmetrical beam and an approximately flat tapered surface adjacent to the coupling facet for reflecting the rapidly diverging radiation, a main body for receiving and transmitting the reflected laser radiation, and an output end having an approximately flat output facet. A support structure situates the coupling facet proximate to the laser diode. A second, approximately flat tapered surface may be formed in the tapered section opposite the first tapered surface. The fiber optic cable may have any cross-section, such as circular, rectangular, or square. The coupler is particularly useful for coupling multiple output beams from a laser diode array into a plurality of fibers that are collected on their output ends to approximate a single beam, which can be then applied to end-pump a solid state laser.

High efficiency fiber optic coupler that reduces beam divergence

An image projection system employing microlaser and/or diode laser arrays. Each laser in each array is individually addressable. The system includes three linear laser arrays, one red, one green, and one blue, each individually addressable laser being powered and modulated in accordance with the input image signal. When microlaser arrays, which are energized by laser diode pumps, are used, the laser diode pumps are formed in equivalent arrays. The laser output beams are combined in a dichroic prism and reflected off a rotating multifaceted scanning mirror which effects two dimensional scanning as it rotates. The image beam reflected from the scanner passes through an imaging lens, a speckle eliminator and then onto the projection screen. The invention also includes the method of generating and scanning the image beam, as well as the novel speckle eliminator and the microlaser array configured for optimally close spacing to achieve the desired result.

A two-metal grating is produced by vacuum depositing a first dielectric cing upon a separation layer formed upon a mandrel; then depositing a first optically opaque metallic layer, etching the layer to form stripes; then vacuum depositing a second optically opaque film; then electroforming a backing structure and separating the dielectric coating from the separation layer on the mandrel to form a free-standing grating structure having a smooth surface. This structure can then be affixed to a metallic mirror. A buried phase grating can also be fabricated by additionally depositing a second dielectric layer and a third metallic layer.

Electroformed buried gratings for high-power shared aperture systems

A flexible light conduit which preserves the coherence of a transmitted beam. Several conduit elements having optical elements mounted inside each one are connected together to form a chain. Each conduit element is tiltably coupled to each adjacent conduit element in the chain. The optical elements may be refractive or reflective. The conduit preserves the spatial coherence properties of the beam so the input image is reimaged at a distant place, having passed through the series of relay optical elements through the angles permitted by the coupling members.

Flexible light conduit

An optical element having a thin, transparent plate containing a plurality of shallow cooling channels, and a transparent substrate immediately behind the plate with a plurality of inlet and exhaust ducts underlying and in fluid communication with coolant being circulated through the cooling channels of the plate. In use, the optical element may be configured as a beam splitter, mirror, or aperture sharing device by applying a coating that is at least partially reflective to the face plate of the element. Alternatively, if used as a window or refractive element, the above cooling structure can be applied to both faces of the element. Optical distortion can be further reduced by using a coolant having a refractive index matching that of the substrate.

Cooled transmissive mirrors, beam splitters, windows, and refractive

A mirror or antenna apparatus having individual petal segments, each of a complex shape, mated with a central hub assembly. Registration pads are provided on the hub assembly to align the petal segments with respect to the hub and each other. Electrical actuators provide fine tuning adjustments in the order of microns.

Hub and petal apparatus for mosaic mirrors and millimeter wave antennas

An infrared scene projector has a cathode ray tube with a display screen coated with a luminescent phosphor material that produces radiation in the infrared spectrum when excited by the electron beam. The desired screen images are generated electronically, the screen is scanned by the cathode ray beam, and the intensity of the beam is modulated by the signal from the image generator.

Growing community of inventors

Albuquerque, NM, United States of America

Graham W Flint