Abstract: A dimension of an object disposed on a substrate, such as the width of a line of material deposited on a substrate in an integrated circuit manufacturing procedure, is measured by directing a plane wave of electromagnetic energy of predetermined dimensions toward the object at a predetermined angle of incidence. Electromagnetic energy scattered from two predetermined parts or features, such as the edges, of the object are combined so that they produce an interference pattern in space varying between maxima and minima. The characteristics of the interference pattern permit the dimension of the object to be deduced.

Abstract: A high resolution periodic pattern is formed in a layer of a photosensitive material by means of a beam of light and a lenticular array formed of a plurality of lenslets. The lenticular array is positioned over the layer and the beam of light is directed through the lenticular array onto the layer. The beam of light is scanned across the lenticular array to pass through the individual lenslets which defines the light into a fine beam and thereby exposes a small area of the layer. The beam is shaped to achieve a periodic pattern in the layer as the beam scans across the layer. By moving the layer in synchronism with the scanning, a two dimensional array of the pattern can be obtained.

Abstract: A random-pattern of microscopic lines that inherently forms in a dielectric coating layer of a 3-layer diffractive subtractive filter authenticating device incorporated in a secure document permits identification of a genuine individual document by comparing read-out line-position information derived by microscopic inspection with read-out digital codes of line-information obtained earlier at the time of fabrication of the document. The technique can also be used with an artificially generated random pattern of lines in the case of other types of authenticating devices that do not inherently form such a pattern.

Abstract: A color encoding filter is provided for use with a camera having a solid-state imager. The filter comprises a plurality of rows of color filter elements, each row having a sequence of color filter elements which repeats after a predetermined number P of elements, wherein P is greater than or equal to eight (8). Sequential rows of the color filter elements are shifted in the row direction by at least two elements from the preceding row such that the combination of vertically aligned filter elements from adjacent rows provides a sequence of at least two independent color combinations. The color combination sequence repeats after a number of combinations equal to the predetermined number P and has like color combinations symmetrically disposed about one color combination of the color combination sequence. A color signal decoding scheme is also disclosed, which features analog signal processing that makes advantageous use of the color filter symmetry.

Abstract: A color filter is provided for use with an imager which has a plurality of discrete collection sites. The filter has a plurality of color filter elements arranged in rows aligned with the collection sites. Two elements of the filter overlay a scan line of the imager in one television field, and each of the rows has a repeating sequence, e.g., 6, of at least two independent colors. The adjacent rows in the filter have their color sequences shifted by two elements. A demultiplexing scheme is disclosed, which features a high-frequency luminance signal having a constant colorimetric composition.

Abstract: A reflective-diffractive coating layer, situated at the interface between a substrate layer and an overcoat layer of the device, is divided into a set of small, slightly separated regions. This allows a direct bond of the overcoat layer to the substrate layer within the separation areas, which direct bond provides a more secure bond than that provided by a bond of the coating layer to the substrate and overcoat layers.

Abstract: An image of periodic color-filter stripes derived by a periodic lenticular array is made to coincide with a periodic pattern of discrete solid-state light cells of an imager, despite manufacturing tolerance errors in the values of the respective periods of the filter and array with respect to the value of the period of the imager. This is accomplished by angularly displacing each of the respective axes of the periods of the filter and imager, with respect to the axis of the period of the array, by a calculable amount.

Abstract: The use of a rhomboid-shaped phase grating to derive, from polychromatic input light, plus-one, minus-one and zero diffraction order output beams each of a different independent color.

Abstract: A variable index-of-refraction optical medium of certain minimum thickness and periodicity with respect to the wavelength of incident light--if it meets certain specified constraints with respect to (1) relative indices-of-refraction of both its internal structure and that of its surroundings and (2) relative values of incident wavelength to periodicity and the relative indices-of-refraction--operates to produce both angularly-dependent subtractive-color filter reflection spectra and subtractive-color filter transmission spectra in accordance with its physical parameters. Such filters are suitable for use as authenticating devices for sheet-material authenticated items.

Abstract: A commercial X-Y positioning table is modified, to limit its dynamic X-positioning error to less than .+-.0.05 micrometer at rates of speed in the Y direction of up to 20 millimeters per second, by mounting an X direction translation stage having fast inertial response characteristics on the Y direction stage of the positioning table and employing an interferometer controlled X position feedback circuit to provide X error compensating movement of the translation stage with respect to dynamic X position errors of the Y direction stage. This permits the generation of sub-micrometer geometry exposure patterns in photoresist for the fabrication of fine relief structures.

Abstract: Markedly increased optical efficiency for a first diffraction order of incident wave energy, such as light, is derived from a layer of transparent material having effectively two serially spaced sinusoidal phase gratings of the same line spacing, each formed as a surface relief pattern thereon, by prescribing the thickness of the layer, the amplitude of the gratings, the respective indices-of-refraction of the layers and of transparent materials bounding the phase grating surfaces thereof, and the angle of incidence of the wave energy.

Abstract: An authenticating device comprises a transparent material, such as a plastic, having a thickness no greater than 100 micrometers embossed on one side with a lenticular array of lenslets having focal lengths substantially equal to this thickness, and embossed on the other side with a reflective relief pattern forming a periodic structure periods smaller than 100 micrometers, which periods are of a width that at least approximates that of the lenslets. The reflective relief structure of the authenticating device is secured to a viewable surface of the authenticated item sheet material and each period of the relief structure is comprised of a set of juxtaposed elements having significantly different reflective characteristics from one another.

Abstract: By selecting the respective values of (1) the f-number of the camera objective, (2) the periodicity of a lenticular array used to image a periodic color encoding filter on a solid-state imager comprised of a periodic spatial pattern of discrete light-sensing cells, and (3) the object and image distances of the array, in accordance with the teachings of this invention, a high-resolution television picture without moire patterns may be generated.

Abstract: A diffractive color filter, comprised of proximately disposed diffraction grating and lenticular lens structures, which may be embossed on plastic sheet, cooperates with an imaging lens to produce color stripes or color spots of an image on a photosensitive surface. The diffractive color filter may be used, for example, as a color-encoding stripe filter of a color TV camera.