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Integrated Semiconductor LED Display Panel

IP.com Disclosure Number: IPCOM000079755D
Original Publication Date: 1973-Aug-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 3 page(s) / 57K

Publishing Venue

IBM

Related People

Anantha, NG: AUTHOR [+4]

Abstract

Integrated semiconductors have successfully replaced all the vacuum tubes in display systems such as a television receiver, for example, except for the cathode-ray tube. The described technique provides a light-emitting diode (LED) display panel, complete with memory cells and the requisite selection circuitry and accessing circuitry on a single monolithic substrate, using basic silicon processing. Small regions of gallium phosphide are selectively grown on silicon or on sapphire, enabling the entire display array to be placed on the same macrochip that also contains all of the required silicon support circuitry.

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Integrated Semiconductor LED Display Panel

Integrated semiconductors have successfully replaced all the vacuum tubes in display systems such as a television receiver, for example, except for the cathode-ray tube. The described technique provides a light-emitting diode (LED) display panel, complete with memory cells and the requisite selection circuitry and accessing circuitry on a single monolithic substrate, using basic silicon processing. Small regions of gallium phosphide are selectively grown on silicon or on sapphire, enabling the entire display array to be placed on the same macrochip that also contains all of the required silicon support circuitry.

In many cases, a display panel is situated at a remote location with respect to the source of signals actuating the display. It is desirable to provide the panel with sufficient memory to store the picture formed by a given pattern of energized light-emitting diodes, in order to reduce the data rate in the communication channel between the display and the source of data signals. Low-data rate is facilitated by eliminating the need for constantly regenerating the nonchanging information. The memory stores the nonchanging information and maintains the corresponding portion of the visual display. It is further desirable that all of the required semiconductor circuitry from the logic to the display element be integrated on one monolithic substrate, to obviate the interconnection problem associated with driving the light-emitting elements from a separate semiconductor support chip.

Monolithic semiconductor chips are "flip-chip" mounted on a glass substrate. Viewing is accomplished through the glass to the active side of the chip. The array of light-emitting diodes, respective memory cells and the associated accessing circuits are formed on the active side of the chip. Each light-emitting diode is driven by a respective memory cell such as a flip-flop, so that the diode is energized when the cell is in a first condition and de-energized when the cell is in its opposite condition. An entire panel may consist of 128K illuminatable spots LED arranged as a 256 by 512 spot array, for example. The spots are continuous, in order that graphics as well as alphanumeric characters can be displayed anywhere on the panel.

Each set of dr...