Abstract: An apparatus enhances the image in a high addressability printer by generating phase signals from a pulse width modulator and a programmable delay or buffer which are XORed with adjacent phase signals and combined with a corresponding data signal to form SET and RESET signals. The SET and RESET signals are used to form a phase and width modulated serial data signal.

Abstract: The present invention provides a independently addressable, high density, edge emitting laser array structure formed by a lateral wet oxidation process. The aperture of the laser structure is formed by selective layer intermixing and lateral wet oxidation from adjacent grooves etched in the laser structure.

Abstract: A telecentric laser beam optical focusing system consists of two diffractive optical elements. The optical system has a spot size of less than one micron and a Strehl ratio of over 0.9 with a f/number of one and a total object/image field of 0.5 micron.

Abstract: A laser beam optical focusing system consists of two symmetrical diffractive optical elements. The optical system has a spot size of less than one micron and a Strehl ratio of over 0.9 with a f/number of one and a total object/image field of either 0.5 or 1 micron.

Abstract: A single pass ROS system provides a plurality of latent images which may subsequently be developed in different colors. The ROS units are initially aligned so that each color image is precisely registered at the same relative position along the exposed area of a photoreceptor belt. The alignment is accomplished by forming a pair of opposed alignment apertures in the surface of the belt and detecting coincidence or lack of coincidence of signals generated by the beginning and end of each scan line. The correction is enabled by rotating the output window in the ROS system, a transmissive optical component with no optical power, subsequent to the ROS, to create the required rotation of the projected scan line. Once the initial X and Y-axis alignments are complete, subsequent alignment is maintained through subsequent passes by checking the positions of the previously identified pixels as they advance past additional lead edge apertures formed in the process direction along the belt surface.

Abstract: A laser beam conditioner consists of a partially reflective surface having a uniform reflectivity of approximately 38.2 percent and a totally reflective surface on opposite sides of a substrate. A coherent light beam incident onto the partially reflective surface of the laser beam conditioner will be partially reflected and partially transmitted. The partially transmitted portion of the coherent light beam will be multiply reflected between the totally reflective mirror and the partially reflective mirror within the beam conditioner, with a portion of light transmitted through the partially reflective mirror at each multiple reflection. The initially reflected portion of the coherent light beam and the transmitted portions of the multiply reflected beams form a conditioned light beam for a homogenizer. The partially reflective surface and the totally reflective surface are slightly less than parallel in order to introduce a minute angular spread among the delayed components of the multiply reflected beam.

Abstract: An achromatic, telecentric f-theta scan lens optical system for a raster output scanner has a positive crown glass lens element, a negative flint lens element and a concave mirror. The refractive indices of the positive crown glass lens element and the negative flint lens element are sufficiently different to achieve achromatization of a light beam by the two lens elements. The positive crown glass lens element, the negative flint lens element and the concave mirror form a telecentric optical system.

Abstract: The optical path length of a raster output scanning (ROS) system is minimized by the use of a laser beam source for emitting a light beam with an enlarged divergence ratio. A super-elliptic light source beam with at least an 8:1 elliptic ratio of the major cross-scan axis to the minor scan axis will minimize the optical path length of a raster output scanning (ROS) system. The large divergence ratio of the super-elliptic light beam reduces the required focal lengths in the ROS optics while maintaining the desired numerical apertures and high energy throughput.

Abstract: A semiconductor laser source using a strained active layer of an indium gallium aluminum nitride (In.sub.x Ga.sub.1-x-y Al.sub.y N) quaternary alloy to obtain semiconductor laser sources that emit TE or TM polarized light in the wavelength range of 200 to 600 nm.

Abstract: The present invention is directed to a precise method of registering a plurality of ROS imagers, so as to form sequential registered images on a photoreceptor belt in a single pass. Pairs of belt holes are formed in the photoreceptor belt, outside the image area and outside of the scan width of the ROS imagers. A pair of light sources are incorporated into the post polygon optics of each ROS imager so as to produce a light spot at the photoreceptor surface which will periodically illuminate the holes on the belt. As the leading edge of the belt holes advances into the beams, detectors placed beneath the belt and beneath the exposure station provide signals representing the exposure level of the light source output. The position of a transmissive optical element with no optical power, subsequent to each of said ROS imagers, is adjusted in response to registration error signals generated by said photodetecting means to adjust the position of said scan lines.

Abstract: In a quantum well semiconductor laser structure, a distributed Bragg reflector is used to select the polarization mode of the emitted light beam. The period of the distributed Bragg reflector matches the peak gain of one polarization mode providing optical feedback for that mode to be the light emitted. The distributed Bragg reflector can extend along the length of the active layer within the semiconductor structure or extend at one end of the active layer external to the semiconductor structure.

Abstract: The polarity of the semiconductor layers in an AlGaInP semiconductor laser fabricated by impurity induced layer disordering (IILD) is reversed to allow n-doping. Thus, the cladding and confinement layers between the substrate and the active layer will have p-type conductivity. The upper confinement, cladding, and contact layers can be either n or p-type conductivity with n-diffused regions formed by IILD extending down from the contact layer to the lower cladding layer. The electrodes can include either a substrate electrode or a lateral electrode.

Abstract: A multiple wavelength surface emitting laser has a first and second broad bandwidth distributed Bragg reflector (DBR) which reflect light at multiple wavelengths. The surface emitting laser structure comprises at least two cavities with each cavity containing one or more active layers for respectively emitting light at different wavelengths. In a preferred embodiment for a dual wavelength surface emitting laser, a first cavity contains a first active layer for emitting light of a first wavelength and a second cavity contains only a second active layers and emits only light of the second longer wavelength. The second layer has been eliminated in the first cavity and the first active layer has been eliminated in the second cavity by layer intermixing before completing the epitaxial growth.

Abstract: A double bounce passive facet tracking system uses a single passive optical component of a toroidal mirror to induce a beam of light to track a facet of a dual mirror rotating polygon. A beam focused in both the tangential and sagittal planes is reflected from a convex facet of the polygon mirror to the toroidal mirror. The toroidal mirror collimates the light beam in a tangential plane and focuses the beam in the sagittal plane so that the beam is collimated in the tangential plane and focussed in the sagittal plane when it reaches the flat facet of the polygon mirror.

Abstract: A penta-level xerographic unit produces five exposure levels on a photoreceptor. The five exposure levels select between a subtractive and an adjacent additive primary color in both the CAD and DAD operational regimes of a xerographic process. Exposure levels intermediate between the CAD and the DAD result in white. The selection of two possible colors in CAD, or two possible colors in DAD, or the selection of no toner yields a possibility of five colors. This penta-level xerographic unit can be used for a K+3 reduced color gamut printer, typically cyan, yellow and red plus black.

Abstract: Two sets of two single blazed binary diffractive optical elements form a beam separation control apparatus for expanding two closely spaced parallel beams into two wider spaced parallel beams or for contracting two wider spaced parallel beams into two closely spaced parallel beams. Four sets of two single blazed binary diffractive optical elements form a beam separation control apparatus for separating two closely spaced parallel beams into two wider spaced parallel beams for possible modulation or other optical effect, then returning the two beams to be closely spaced and parallel. A set of two adjacent and opposite single blazed binary diffractive optical elements can form a beam splitting apparatus or a beam combining apparatus.

Abstract: In situ removal of selected or patterned portions of semiconductor layers is accomplished by induced evaporation enhancement to form reversed bias current confinement structures in semiconductor devices, such as heterostructure lasers and array lasers.

Abstract: A two photoconductive stack photoreceptor has an electrically conductive substrate upon which are two photoconductive stacks with each photoconductive stack sensitive to or accessible to a different wavelength of light. After charging of the photoreceptor, areas of the photoreceptor are exposed to no light beams, a first light beam, a second light beam or both light beams which allows different toners to be deposited on the photoreceptor in response to the remaining areas of charges. This two photoconductive stack photoreceptor produces a color xerographic printing system. The photoreceptor can also have multiple photoconductive stacks.

Abstract: A double blazed binary diffractive optical element beam splitter having alternating and opposing individual blazed diffraction gratings upon a multilevel surface relief phase grating structure for splitting an incident monochromatic light beam into a first and second diffracted light beams. The double blazed binary diffractive optical element and two single blazed binary diffractive optical elements can form either a beam splitting apparatus or a beam combining apparatus. Double blazed binary diffractive optical elements and sets of two single blazed binary diffractive optical elements can form beam splitting and combining apparatuses to produce a single beam or two closely spaced beams.

Abstract: A single pass full color printing system consists generally of a raster output scanner (ROS) optical system and a quad-level xerographic unit and a penta-level xerographic unit in tandem. This full color printing system produces pixels of black and white and all six primary colors without toner upon toner.