Abstract: A single width bar code exhibiting inherent self clocking characteristics is provided so as to be particularly useful in the identification of semiconductor wafers in very large scale integrated circuit manufacturing processes. The codes described herein are robust, reliable and highly readable even in the face of relatively high variations in scanning speed. The codes are also desirably dense in terms of character representations per linear centimeter, an important consideration in semiconductor manufacturing wherein space on the chips and the wafer is at a premium. Additionally, a preferred embodiment of the present invention exhibits a minimum number for the maximum number of spaces between adjacent bars in code symbol sequences.

Abstract: Apparatus for masking a displayed image by mixing the image with a secondary image that is electronically generated to be related to the primary image that when combined with the primary image obscures viewing of the primary image. The primary image is generated in the form of a first set of wavelength bands and the secondary image is a second set of related wavelength bands. A filter is provided to absorb the second set of wavelength bands to permit secure viewing of the primary image.

Abstract: A display assembly includes a display screen having a predetermined generally planar area for displaying transmissive data. A light source is provided for generating light of predetermined intensity, and a circular Fresnel lens is disposed between the light source and the display means, the circular Fresnel lens imaging the light source through the display means and onto an opposite side of the display means. A diffuser is disposed between the light source and the display means for diffusing the light. The intensity of the light source is selected to be appropriate for direct human viewing of the transmissive data.

Abstract: An image projection system for all surfaces of a three dimensional object such as a polyhedron in which direct and angle reflected image patterns are projected from superpositioned non-overlapping mask patterns mounted on different levels where the separation of the levels is related to the size of the object. The apparatus and process permits simultaneous photolithigraphic printing of conductors on the top and all sides of a cube shaped stack of integrated circuit chips.

Abstract: Disclosed are methods and apparatus for fabricating a three-dimensional object in accordance with a computer-generated definition of the object that is stored within a memory. A method includes the steps of (a) evaluating the stored definition of the object to locate any un-supported features of the object; in response to locating an un-supported feature, (b) defining a support structure for the un-supported feature; (c) generating a fabrication tool movement list expressive of movements required by a fabrication tool to fabricate the object and any defined support structures; and (d) translating the fabrication tool in accordance with the generated fabrication tool movement list to fabricate the object and any defined support structures.

Abstract: A mask and a fabrication method therefor that incorporates a patterned radiation blocking layer such as a second patterned high-reflectivity dielectric coating on the back surface of the mask which also includes a first patterned reflective coating on the front. This second high-reflective dielectric coating referred to as a premask, eliminates most of the laser energy directed onto the mask that leads only to substrate heating without effecting the laser energy transmitted through the open area of the mask. The open areas of the premask are sufficiently larger than those in the mask so not to interfere with the illumination geometry (i.e. forms a greater angle than the illumination numerical aperture).

Abstract: A through-the-lens method and system for focusing a projected image onto an imaging surface employs a confocal process and apparatus. Electromagnetic radiation projected through a subresolution aperture of origin located in an object plane passes through a confocal imaging device which forms an image of the aperture in the image plane. The radiation strikes the surface and is reflected back through the confocal imaging device to the aperture. The power of reflected radiation passing through the aperture is detected/measured. The distance between the imaging surface and the imaging device is then adjusted to maximize the detected power.

Abstract: Apparatus and method for fabricating a three-dimensional object in accordance with a CAD-generated specification of the object. A closed-loop extrusion system (10) includes a nozzle (12) for extruding a material, such as a hot melt adhesive; apparatus (14, 18, 46) for controllably positioning the nozzle in accordance with the specification; and a sensor (60) for generating a feedback signal that is indicative of at least one characteristic of a most recently extruded portion of the material. Visual and non-visual feedback sensors may be employed, including optical sensors, infrared emission sensors, and proximity detection sensors. The specification of the object is converted to a bit-mapped representation thereof to improve accuracy relative to vector-based representations. Methods for determining a need for supporting structures and anti-aliasing features and for integrating the structures and features into the object specification are also disclosed.

Abstract: A lens system having discrete variations of focal length at discrete distances of radius outward from the optic axis for focussing light of plural wavelengths. The lens system which directs a laser beam onto a target for ablation or exposure applications includes one set of lens elements to handle short wavelength light used for ablation or exposure applications, and another set of lens elements to handle long wavelength light used for alignment applications. The lens system which provides for the ablation or exposure functions at short wavelength and for through-the-lens alignment at a longer wavelength and higher numerical aperture consists of three elements. Two outer lens elements are made entirely of fused quartz. An inner element disposed between the two outer lens is composed of any material such as optical glass. The inner lens element has a hole ground through its center.

Abstract: An optical system having a plurality of substantially planar reflecting surfaces and a plurality of curved reflecting surfaces providing an optical projection system which can scan a mask object onto an image plane by having the mask and copy substrate substantially fixed in position relative to each other and either simultaneously moving the mask and copy substrate in the same direction or maintaining the mask and image plane substantially stationary and fixed with respect to each other while scanning the optical system. The optical system uses one wavelength of an electromagnetic radiation to align the mask to the copy substrate and another wavelength of electromagnetic radiation to form the image of the mask on the copy substrate. The apparatus can be used as a laser ablation optical tool to laser ablate the image of a mask onto the copy substrate, as an inspection tool, as a photolithographic and for other related applications. The projection lens is a modified Dyson type lens.

Abstract: A phase retardation element, for use in an optical data storage system, which provides a 90.degree. phase difference between two perpendicular polarized components of an incident wave with a single internal reflection from a surface coated with a thin film of dielectric or metal material.

Abstract: The physical separation between a rear illuminated opaque pattern on a translucent substrate and an optical pattern sensing device viewing the shadow image of the opaque pattern is increased without any corresponding loss of resolution (and/or resolution may be increased without any corresponding reduction in the physical separation between the optical pattern sensing device and the opaque pattern) by positioning a narrow spectral band pass interference filter between the opaque pattern and the optical pattern sensing device, and using as the rear illumination, light having a spectrally narrow band which substantially matches the pass band of the interference filter.