Abstract: A vision system is provided to determine a positional relationship between a semiconductor wafer on a platen and an element on a processing machine, such as a printing screen, on a remote side of the semiconductor wafer from the platen. A source directs ultraviolet light through an aperture in the platen to illuminate the semiconductor wafer and cast a shadow onto the element adjacent an edge of the semiconductor wafer. A video camera produces an image using light received from the platen aperture, wherein some of that received light was reflected by the wafer. The edge of the semiconductor wafer in the image is well defined by a dark/light transition.

Abstract: A vision system is provided to determine a positional relationship between a photovoltaic device wafer on a platen and a printing element, such as a printing screen, on a remote side of the photovoltaic device wafer from the platen. A source emits ultraviolet light along a path that is transverse to a longitudinal axis of an aperture through the platen, and a diffuser panel is located along that path. A reflector directs the light from the diffuser panel toward the aperture. A video camera is located along the longitudinal axis of the aperture and produces an image using light received from the platen aperture, wherein some of that received light was reflected by the wafer. A band-pass filter is placed in front of the camera to block ambient light. The use of diffused ultraviolet light enhances contrast in the image between the wafer and the printing element.

Abstract: A vision system is provided to determine a positional relationship between a semiconductor wafer on a platen and an element on a processing machine, such as a printing screen, on a remote side of the semiconductor wafer from the platen. A source directs ultraviolet light through an aperture in the platen to illuminate the semiconductor wafer and cast a shadow onto the element adjacent an edge of the semiconductor wafer. A video camera produces an image using light received from the platen aperture, wherein some of that received light was reflected by the wafer. The edge of the semiconductor wafer in the image is well defined by a dark/light transition.

Abstract: A vision system is provided to determine a positional relationship between a photovoltaic device wafer on a platen and a printing element, such as a printing screen, on a remote side of the photovoltaic device wafer from the platen. A source emits ultraviolet light along a path that is transverse to a longitudinal axis of an aperture through the platen, and a diffuser panel is located along that path. A reflector directs the light from the diffuser panel toward the aperture. A video camera is located along the longitudinal axis of the aperture and produces an image using light received from the platen aperture, wherein some of that received light was reflected by the wafer. A band-pass filter is placed in front of the camera to block ambient light. The use of diffused ultraviolet light enhances contrast in the image between the wafer and the printing element.

Abstract: The present invention relates generally to bending a workpiece to form a desired configuration and, in particular, to a method and apparatus for forming bends "out of sequence," i.e., in a time sequence different from the spatial sequence of the bends on the workpiece. The apparatus of the present invention include a bending system for bending a workpiece and a positioning system for positioning the workpiece relative to a bending region so that bends can be formed in various locations across the bending region. By virtue of the disclosed structures, a series of bends can be formed on a workpiece at various locations within the bending region. Bends can be formed out sequence and without advancing the workpiece relative to the bending region.