Abstract: A video magnifier is provided for capturing images [1] in the fixed shutter mode when the user selects the positive video polarity and [2] in the variable shutter mode when the user selects the negative video polarity. During the fixed shutter mode operation, an image capturing device of the video magnifier has an exposure time that is one half of a period of a cycle of the ac power line.

Abstract: The document scanner of the present invention includes a reading assembly of simple, compact and light-weight construction. The reading assembly includes an optical system having a relatively short focal length. The reading assembly is thus simply configured in a compact manner close to the document to be scanned. The optical system is also configured to extend in a particular direction beyond the document viewing area for improved resolution of images from a bound document adjacent the binding. The reading assembly further includes a compact and light-weight illumination source which is low in power consumption, and thus, may be powered by batteries. The stand-alone document scanner of the present invention is particularly suited to portability.

Abstract: A zoom lens is described which is quite simple and yet provides a wide (5:1) zoom range. The lens consists of a front focusing negative lens which provides a stationary virtual image for two rear zooming lens groups. These two zooming groups are positive and reimage the object at a camera pickup device. Such zooming groups are of substantially equal focal length and bear equally in the magnification change. The invention includes a magnifier which utilizes the zoom lens and has the mechanical aspects necessary to provide the needed lens motions.

Abstract: A braille cell assembly is described which provides precision cell positioning. Such assembly includes a holder in the form of a tray which engages the individual braille cells, which holder is selected to be capable of itself rigidly maintaining the individual cells in predetermined positions adjacent to one another. The position of each cell in the assembly is thus independent of other cells of the assembly.