Abstract: An electromagnetic energy interference seal arrangement is provided for use in light beam touch panel systems. The electromagnetic energy interference seal includes the use of waveguides associated with the light beam sources and detectors to improve light beam touch panel performance. The waveguide size is selected so that it operates as a waveguide above cutoff frequency for the light beams but operates as a waveguide below cutoff frequency for blocking electromagnetic energy interference. The waveguides improve the light beam signal to noise ratio since they shade the detectors from reflections and from extraneous light such as from overhead room lighting. Bonding of part of the electromagnetic energy interference seal is effected by an electrically conductive compound which enables nondestructive disassembly when required. Environmental sealing strips are provided to cover the waveguide apertures to protect against dust, liquids and other environmental contaminants.

Abstract: A touch panel system for displays is provided having electromagnetic energy interference shielding arrangements coupled with other features for an integrated, easily maintained, operator-adapted touch panel system. The system includes an electromagnetic energy interference shielding bezel mounted at the front of the display unit to an outer display housing. The bezel is integrated with an optically transparent and electrically conductive faceplate covering the display, and a raised border with an associated electromagnetic energy interference seal located at the periphery of the active touch panel area which is disposed between the faceplate and the bezel to complete an electrical path. The faceplate is roughened to disperse spatial interference patterns and reflections, and in one embodiment, has an electrically conductive wire mesh disposed within it for electromagnetic energy interference sealing and contrast enhancement for filtering extraneous light in the manner of a venetian blind.

Abstract: A circuit for reducing noise and increasing the reliability of touch panels involves the use of a supplemental noise or electromagnetic interference pickup lead which extends generally coextensively with the parallel connected outputs from a series of successively coupled photodetectors and a high pass filter for substantially reducing the noise signals created by variations in the level of ambient light. When the photodetectors output is connected to one of the inputs of a differential operational amplifier, and the compensating pickup lead is connected to the opposite polarity other input, the noise is substantially cancelled out, and a cleaned-up photodetector pulse is provided. A pulse forming circuit squares up the photodetector output signal pulse; and a hysteresis type storage or buffer 15 circuit is employed to indicate the presence or absence of photodetector output signals, from successive photodectors, thereby indicating whether or not the light beams are interrupted either fully or partially.

Abstract: An article positionable in a conventional light bulb socket for decreasing the power input and limiting the power turn-on and turn-off transients to a bulb inserted into such socket to thereby increase the life expectancy of the light bulb. The article includes a wafer of insulating material having a notch in the perimeter thereof, an axial lead diode or other power decreasing and/or transient limiting device positioned in the notch, the leads of the device extending radially inwardly and being positioned and/or coiled into spiral patterns or other patterns to form electrical terminals at the center of the wafer, on opposite sides thereof, and a pair of flexible pads of insulating material having widths approximately equal to the inside diameter of the base of the light bulb socket, the pads being secured to opposite sides of the wafer, the diode, and each other, each pad having a central opening therein to expose the electrical terminals.