Abstract: A light directing element (22) used in a Scheimpflug system (10, 12, 14, 16, 18) includes an array of closely packed optical fibers (40) formed as a plate (34) having essentially parallel entrance and exit sides (36, 38), the axis (44) of each fiber of the array being essentially perpendicular to the exit side and at a first oblique angle (.gamma.) to a normal to the entrance side, the normal to the entrance side being at a second oblique angle (.alpha.) to the first axis; so that, each fiber receives light from the first optical system, each fiber being curved between the entrance and exit sides. Oblique objects can be viewed in real time using electronic detectors (28-32) which receive light emitted from the exit side. Objects with topographical features (11) may be viewed by providing the entrance side with an optically conjugate surface of topography (23).

Abstract: A tubular illuminator for focusing a bright line of approximately specular illumination onto the surface of a web moving at high speed to detect defects usually in the surface of the web.

Abstract: An optical system for a bar code scanner has a working range that is not determined by the lens aperture, but by the dimension and orientation of the detector. In the preferred embodiment, the desired working range is imaged onto a detector array using a modified Scheimpflug arrangement. The array in the first Scheimpflug plane with respect to the lens defines a second Scheimpflug plane that intersects the bar code tag to be read. So long as the bar code tag intersects the image of the detector array in the second Scheimpflug plane, a portion of the image of the bar code tag will be in focus on at least one of the elements of the detector array. The lens aperture can be as large as desired to maximize resolution and minimize illumination needs without adversely affecting the working range. The scanner's bar code illumination can be directed along the second Scheimpflug plane, which is off the optical axis of the lens.

Abstract: In a scanning apparatus, a scanned transverse region of a moving web is illuminated by focused illumination from an elongate incandescent lamp with a long filament maintained in tension and supported only at its ends to prevent shadows or other luminance variations along the length of the lamp.

Abstract: A scanning bar code reader which includes a lens and a multi-zone detector. The zones have differing distances from the principal plane of the lens so that one zone will have on it a better focussed image of the bar code symbol than do the others. The zones are electronically scanned. The lens includes a plurality of regions of differing focal lengths and/or different principal planes which promote a magnification which is not directly related to distance of the symbol from the reader. A stop restricts the rays reaching a particular zone of the detector to those which have been refracted by the lens region which gives the best focussed image on the particular zone from a symbol at a predetermined distance.