Abstract: A low profile opto-device panel assembly suitable for use in an input detection apparatus used as an input device in conjunction with a visual display is disclosed. Arrays of light emitting devices and light detecting devices are juxtaposed along the internal edge of a peripheral frame printed circuit board to reduce the overall height of the panel assembly. Alignment housings surrounding each of the arrays of opto-devices are attached to the printed circuit board and extend inwardly of the sides of the peripheral frame printed circuit board. The opto-devices disposed in the alignment housings along the internal edge of the printed circuit boards are mechanically and electrically interconnected to the printed circuit board by bent leads which extend along the upper surface of the printed circuit board and into conventional printed circuit board holes.

Abstract: A touch entry system employing arrays of emitter and detector opto devices located around the periphery of an irradiated field detects intrusion of an opaque element such as a stylus within the field. The detector analog output is converted to a digital signal for input into a microprocessor. Digital signals input into the microprocessor can vary due to inconsistencies in conventional opto devices. A programmable amplifier responsive to the microprocessors preconditions the analog signals prior to analog to digital conversion to bring all digital signals corresponding to the unblocked emitter beam condition within a normalized range before input into the microprocessor.