Abstract: A reduction/enlargement gradient index lens array is modified to improve image quality and exposure at an imaging plane. In one embodiment, a masking element is placed in the optical path so as to permit minimum light transmitted through optical fibers located at the array ends and maximum light transmitted through the array center. In a second embodiment, a field stop is formed within the body of each fiber to accomplish the same end.

Abstract: A gradient index lens array is formed by assembling a plurality of gradient index fibers into a single row. The fiber parameters and fiber-to-fiber spacing are optimized to provide required illumination level while minimizing illumination spatial modulation.

Abstract: An optical system is provided for a reproducing machine which scans an object to be reproduced, utilizing a pulsing light source to illuminate successive incremental portions of the object. The ray reflected from the scanned image is directed along an optical path onto the imaging plane. The scanned image is directed onto the imaging plane by a reflector element which has an active slit formed on its surface. The reflector element is positioned an optimum distance from the imaging plane such that the image is defocused at more than one magnification ratio.

Abstract: A facetted reflector faces a linear scanning illumination source and directs light onto an object plane. The tilt angle and length of each linear mirror segment (facet) comprising the reflector are designed to achieve maximum illumination at an object scan line consistent with the geometry of the particular illumination system.

Abstract: A gradient index lens array is provided with reduction and enlargement capabilities. Gradient index fibers are arranged in single row or double row (bundled) configuration with fibers increasingly departing from the perpendicular condition at the center of the array relative to object and image planes in a characteristic fan-like manner. Fiber lengths are adjusted to compensate for changes in total conjugate which occur because of the progressive tilting of the axes of the individual fiber lenses. This is achieved, in one embodiment, by grinding the faces of a lens array into a convex configuration.

Abstract: In an optical system for a multi-magnification copying device, a relative illumination filter is mounted in a fixed position relative to the projection lens with the center on the lens optical axis. The filter provides a radially varying transmission therethrough which compensates for circularly symmetric nonuniformities in the optical system at any magnification.

Abstract: Several types of transmission filters are disclosed having specified transmittance functions to eliminate strobing in scanning an image through an aperture onto a photoreceptor. A general requirement or condition on photoreceptor irradiance profiles has been found to minimize strobing. photoreceptor irradiance profiles are generally the product of the time irradiance function of the periodically energized illuminating lamp and the spatial irradiance profile across the aperture near the photoreceptor. It has been found that strobing is eliminated if the Fourier transform of the spatial irradiance profile is zero, evaluated at the fundamental frequency of the illuminating lamp and at those multiples of the fundamental frequency at which the lamp has power. A transmission filter with predetermined transmittance characteristics therefore, can be disposed in the image path near the aperture to provide a spatial irradiance profile having a zero Fourier transform at the required spatial frequencies.

Abstract: A facetted reflector faces a linear scanning illumination source and directs light onto an object plane. The tilt angle and length of each linear mirror segment (facet) comprising the reflector are designed to achieve maximum illumination at an object scan line consistent with the geometry of the particular illumination system.

Abstract: A low pressure sodium vapor lamp including a sodium vapor discharge tube and a light reflector partially surrounding the discharge tube and defining a light transmission aperture for desired directional light output. The light reflector is in tangential contact with the discharge tube on the surface thereof opposite to the light aperture. The contact between discharge tube and light reflector provides a thermal coupling for heat conduction from the discharge tube. The area of this thermal coupling thus becomes the coolest portion of the discharge tube, the "cold spot" of the lamp where excess sodium is condensed.

Abstract: Apparatus and method for modulating quasi-monochromatic electromagnetic radiation utilizing a controllable diffraction grating. A reflection diffraction grating is comprised of a material deformable in the presence of an applied electric field. A first electrode, comprised of a flexible radiation-reflecting material, is applied to the first surface of the deformable material, forming a reflecting surface of the diffraction grating. A second electrode is applied to a second surface of the deformable material. The electrodes are arranged to provide a periodic surface distortion on the reflecting electrode upon application of a voltage between the first and the second electrodes, thereby resulting in a blazed diffraction grating. In addition, the blaze angle of the diffraction grating can be varied as a function of applied voltage, and consequently diffracted radiation pattern can be modulated as a function of the applied voltage.