Abstract: A writing apparatus (10) for forming images from digital data onto color motion picture film or other photosensitive media (32), the apparatus employing a single spatial light modulator (30) and having a hybrid light source (20) with three components: a red laser (40), a green laser (42), and one or more blue LEDs (18). Each component of the light source is adapted to the sensitometric response characteristics of a particular motion picture film type. The apparatus allows high-speed imaging to photosensitive media (32).

Abstract: An apparatus and method of printing images onto a photosensitive media (140) using multiple reflective spatial light modulators (87, 88, 89, 90, 95, 97). In the apparatus and method, illumination optics uniformize and image light from at least one light source (20) through polarization beamsplitting elements (60, 63). The polarization beamsplitting elements (60, 63) divide the illumination light into two polarization states. One polarization state of the illumination light illuminates the reflective spatial light modulators (87, 88, 89, 90, 95, 97) in a telecentric manner. The reflective spatial light modulators (87, 88, 89, 90, 95, 97) are addressed with image data signals. The reflective spatial light modulators (87, 88, 89, 90, 95, 97) modulate the polarized illumination light on a site by site basis and reflect the modulated light back through the polarization beamsplitting elements.

Abstract: A system and method for reducing or eliminating the speckle intensity distribution of a laser imaging system. In one embodiment of the invention, a radio frequency signal is injected into a semiconductor laser light source (12) for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, optical feedback is used to induce a laser light source for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, the laser light source wavelength is Doppler shifted to produce different speckle patterns. In another embodiment of the invention, a means of deflection is used to directionally move the beam to reduce noticeable speckle.

Abstract: A system and method of stabilizing laser output levels includes a laser (10), an injection circuit for injecting a radio frequency waveform, and a control circuit for energizing and stabilizing the laser. The radio frequency waveform injected by the injection circuit has a high duty cycle to maintain high output power while providing a stable multimode spectrum. A back facet photodiode sensor (102) detects radiation emitted from a back facet semiconductor laser (101) and provides a feedback signal to the control circuit (41) for maintaining the laser output power. The response of the photodiode is not fast enough to track intensity variations due to the RF waveform, and thus provides feedback to the control circuit (41) only when there is a substantial need to adjust laser power.

Abstract: A system and method for reducing or eliminating the speckle intensity distribution of a laser imaging system. In one embodiment of the invention, a radio frequency signal is injected into a semiconductor laser light source (12) for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, optical feedback is used to induce a laser light source for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, the laser light source wavelength is Doppler shifted to produce different speckle patterns. In another embodiment of the invention, a means of deflection is used to directionally move the beam to reduce noticeable speckle.

Abstract: A system and method for reducing or eliminating the speckle intensity distribution of a laser imaging system. In one embodiment of the invention, a radio frequency signal is injected into a semiconductor laser light source (12) for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, optical feedback is used to induce a laser light source for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, the laser light source wavelength is Doppler shifted to produce different speckle patterns. In another embodiment of the invention, a means of deflection is used to directionally move the beam to reduce noticeable speckle.

Abstract: An apparatus and method of printing images (10) onto a photosensitive media (140) using multiple reflective spatial light modulators. In the apparatus and method, illumination optics (25) uniformize and image light from at least one light source through polarization beamsplitting elements (80). The polarization beamsplitting elements (80) divide the illumination light into two polarization states. One polarization state of the illumination light illuminates the reflective spatial light modulators in a telecentric manner. The reflective spatial light modulators are addressed with image data signals. The reflective spatial light modulators modulate the polarized illumination light on a site by site basis and reflect the modulated light back through the polarized beamsplitting elements (80). The modulated light beams are combined to form an image, which is directed through a print lens (110) to expose a photosensitive media (140).

Abstract: A system and method for reducing or eliminating the speckle intensity distribution of a laser imaging system. In one embodiment of the invention, a radio frequency signal is injected into a semiconductor laser light source (12) for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, optical feedback is used to induce a laser light source for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, the laser light source wavelength is Doppler shifted to produce different speckle patterns. In another embodiment of the invention, a means of deflection is used to directionally move the beam to reduce noticeable speckle.

Abstract: A system and method of controlling laser power output levels includes a laser (9) and a control circuit (27) for energizing the laser. A sensor (11) that measures power output from a back facet of a laser element (17) of the laser provides feedback to the control circuit so as to maintain power output from the laser constant. The back facet of the laser element is covered with a coating that has transmission and reflection characteristics that are relatively insensitive to minor changes in the wavelength of the laser. The coating is preferably a thin metallic layer which provides a constant and adequate reflectivity and low transmittance. With the specific metallic layer on the back facet, the transmittance remains relatively consistent even when there is a change in wavelength. This provides for consistent readings at the sensor.

Abstract: A stabilized laser is comprised of a laser for generating radiation responsive to a control signal. A control circuit connected to the laser provides the control signal and an injection circuit injects a radio frequency into the control circuit and the control signal. A back facet photodiode sensor detects radiation emitted from a back faceted laser diode and provides a feedback signal to the control circuit for adjusting laser output power.

Abstract: Laser beam scanning system combines multiple light beams, each of differing wavelengths, to achieve a multiple wavelength scan exposure of a medium, or to increase throughput by writing plural lines simultaneously, or to provide one or more scanning beams of selected wavelength. A polarizing beam splitting prism of the Thompson type is employed as a multiple input beam combiner. The two input laser beam components can be made selectively coincident or closely parallel to form an output beam which is then redirected in a scanning motion and focused to an exposure plane.

Abstract: By modifying the exposure sequence of the facets in a hologon during manufacture, it is intended to maximize the spatial frequency of the error especially in hologons having large numbers of facets so that the error frequency is multiplied by a large factor, thereby greatly reducing the eye's ability to detect banding problems. This method also minimizes the adjacent facet error as far as is practical.

Abstract: By modifying the exposure sequence of the facets during manufacture of a hologon image writer the visibility of cross scan errors are minimized, thereby reducing exposure error and visible banding. With hologons having a number of facets "n" the general form of the exposure sequence is 1, n, 2, n-1, 3, n-2 . . . .

Abstract: Laser beam scanning system combines multiple light beams to achieve a selectable intensity, high power scanning beam. A polarizing beam splitting prism of the Thompson type is employed as a multiple input beam combiner. The input laser beam components can be made selectively coincident or closely parallel to form an output beam which is then redirected in a scanning motion and focused to an exposure plane.

Abstract: A three-color laser scanner using a holographically-generated plane linear grating disk (hologon). The disk includes peripherally-arranged facets having identical multiplexed diffraction gratings. Each multiplexed grating is formed from plural superimposed interference patterns accumulated by multiple exposures to light from a single monochromatic laser beam source. The multiplexed grating is optimized to diffract certain light wavelengths in a single, multichromatic (plural wavelength) input laser beam. The diffracted output beam comprises respective wavelength beam components that simultaneously scan in collinear fashion. Modulation of the plural wavelength components in the incident beam allows the output beam to scan expose a multicolor image at the image plane.

Abstract: A large format laser scanning system is disclosed that incorporates a compact, wobble free and wavelength insensitive scanning mechanism. The scanning mechanism includes a pentaprism and lens mounted on a rotating frame assembly that is located within a scanning drum. Multiple light beams generated by a light source are passed through the rotating pentaprism and lens to scan a photosensitive medium located on the interior surface of the scanning drum.

Abstract: A multichannel integrated optics modulator is disclosed that generates one or more independently modulated scanning beams. The integrated optics modulator includes at least one waveguide channel provided on an electro-optic substrate, wherein the waveguide channel is divided into a write waveguide channel that extends to an output side of the substrate and a dead-end waveguide channel that terminates before reaching the output side of the substrate. Control signals are selectively applied to electrodes provided above the dead-end waveguide channel and the write waveguide channel to control the coupling of light from the write waveguide channel to the dead-end waveguide channel. Light is coupled out of the dead-end waveguide channel through the use of an absorber located above an end region of the dead-end channel. The integrated optics modulator is incorporated in a variety of scanner mechanisms.

Abstract: A method and apparatus is provided for line scanning a beam receiving member, wherein a scanning beam is angularly or laterally displaced to compensate for scan line spacing error. The beam is displaced according to error arising from variation (flutter) in the relative motion of the beam and the beam receiving member, or according to error arising from movement of the receiving member while the scanning beam travels to a start of scan position, or both. Embodiments of beam displacement means include a refracting tilt plate, a reflecting tilt plate, a diffracting tilt plate, and a tilt prism.

Abstract: Moire patterns in raster-scanned halftone dots image screens generated by multi-element line scanner devices are rendered imperceptible to the human eye by selecting the number of elements in the line scanner device to be that number which makes the "once-around" scanner frequency an integral multiple of the halftone dot screen frequency and makes the beat frequencies between the scanner and frequencies either fall outside the nominal visible spatial frequency range of about 2.5 to 250 lines per inch or fall on the screen frequency.

Abstract: A scanner including a source of coherent light, a radial hologon, a f.theta. lens and a target. Between the light source and the hologon there are means for forming light from the source into a collimated beam having an oblong cross-sectional shape and for directing the beam onto the hologon at a predetermined incident angle and with the long axis of the oblong cross-sectional shape of the beam radial of the axis of rotation of the hologon. Prismatic means are provided between the hologon and the lens means for so modifying the cross-sectional shape of the beam that the spot at the target station has a selected shape and orientation. This allows the shape, orientation and size of the beam on the hologon to be optimum for duty cycle of the hologon and for spot size on the target. The prismatic means allows the spot shape and orientation on target to be optimized. The prismatic means tends to introduce undesirable bow into the scan line, therefore the wavelength of the light and the grating factor (n .lambda.