Eugene S. Schlig

IBM's Linux watch, the challenge of miniaturization

Nearly four years in development, the IBM Linux watch contains a complete computer system that runs Linux, displays X11 graphics, and has wireless connectivity. The system fits in a case that could pass as a slightly unusual analog timepiece with a somewhat odd shape and an extraordinarily brilliant face. The developers have created two versions of the watch, one with an organic light-emitting diode display and the other with a liquid crystal display. Still considered a research prototype, the watch already runs some personal information management applications, and it can communicate with PCs, PDAs, and other wireless-enabled devices, viewing condensed e-mail and directly receiving pager-like messages. Eventually, users will be able to access various Internet-based services, such as up-to-the-minute information about weather, traffic conditions, the stock market, and sports.

Design and fabrication of a prototype projection data monitor with high information content

A prototype 28-in.-diagonal desktop data monitor capable of displaying 2048 × 2048- pixel images has been designed, built, and evaluated. The monitor uses optical projection technology. A reflective, crystalline silicon active-matrix light valve using liquid crystal electro-optics and a digital electronic interface architecture is described. This rear-projection monitor has four million resolvable pixels, uses three light valves to achieve color, has a low-gain surface diffuser screen, and functions as a fully interactive, color personal computer monitor with motion video capability. The monitor is 20 in. deep.

Silicon light-valve array chip for high-resolution reflective liquid crystal projection displays

A crystalline silicon active-matrix 2048 × 2048- pixel light-valve array chip has been designed and fabricated as part of the development of a reflective liquid crystal technology for projection displays. The small feature processing and higher circuit performance available with crystalline silicon technology were exploited for the design and fabrication of the active-matrix chip. A 10-V CMOS process was developed to satisfy active-matrix pixel-cell requirements. Row-selection circuits were integrated which incorporate redundant data paths. Adjacent-line demultiplexing circuitry was integrated to minimize the number of external data drivers, to minimize the number of connections, and to maximize chip yield. The pixel, row-driver, and data-driver demultiplexing circuit designs and performance are discussed. The testing methods are presented, The chip is 64 mm on a side and is used in a prototype rear-projection color display system. Companion papers describe the system and its additional components incorporated in the prototype display system.

24.2 Direct View Active Matrix VGA OLED-on-Crystalline-Silicon Display

This paper describes the pixel and array circuitry, which includes a CMOS SRAM cell and a precision current source at each pixel, of a direct view VGA active matrix OLED-on-crystalline-silicon display, developed jointly by IBM Research Division and eMagin Corporation. The display has applications for low-power personal information appliances such as a computer wristwatch. The display obtains data and control signals directly from the memory bus of the appliances processor.

Electrothermal considerations in display applications of light-emitting diodes

Some of the possibilities and problems of high-density integration and packaging of light-emitting diode displays are explored, using a new electrothermal characterization of light-emitting diodes. After a brief discussion of thermal effects in spontaneous light-emitting diodes, the characterization is derived. It reveals a peak in luminance with increasing electric power due to self heating. Experimental results confirm the accuracy of the characterization for gallium arsenide phosphide monolithic displays. Finally, the characterization is used to evaluate some projected high power-density applications. These particularly involve dense diode arrays and the use of higher levels of integration, together with magnification by projection of an image onto a screen, to reduce the cost per element associated with processed chip area. Self heating is found to cause a strong dependence of the luminance on the number of elements powered in a dense array, and to limit severely the achievable magnification even with improved packaging.

Nondestructive graphic cursors and light-pen tracking on AC gas-discharge display panels

Interactive graphic displays need a displayed cursor such as a cross-hair to provide the system user with feedback of the systems point of attention. It has proven difficult to provide a movable cursor on ac gas-discharge displays without regenerating the original image each time the cursor is moved. This paper presents a new technique for displaying nondestructive cursors of various forms on gas panels and for high-speed automatic light-pen detection and tracking.

An SXGA reflective liquid crystal projection light valve incorporating inversion by pixel bootstrapping

A new experimental SXGA liquid-crystal-on-silicon reflective projection light valve is described. It incorporates a novel inversion scheme, the bootstrapped pixel method, which extends the available pixel voltage range with lower applied voltages from the external data driver. This can enable the use of liquid crystal modes and performance-enhancing pixel structures which increase the pixel voltage requirement without incurring the additional cost of higher-voltage technology in the light-valve chip or the data driver. Alternatively, with present liquid crystal modes and pixel structures, it can permit the use of a denser, lower-voltage silicon process permitting more function on a chip or smaller, less expensive chips. Using the new light valve, the pixels were operated at 12 V peak-to-peak, the technology maximum, with no voltages in the device above 12 V and a data-line voltage range of 6 V. The new method introduces no new image artifacts.

Output structure for buried-channel CCD

An output structure for buried-channel charge coupled devices (CCD) is presented which permits output voltage swings of several volts without restricting the design of the buried-channel or requiring excessive drain voltage. Its application to experimental CCD imaging devices is discussed.

Technology and design of an active-matrix OLED on crystalline silicon direct-view display for a wristwatch computer

The IBM Research Division and eMagin Corp. jointly have developed a low-power VGA direct view active matrix OLED display, fabricated on a crystalline silicon CMOS chip. The display is incorporated in IBM prototype wristwatch computers running the Linus operating system. IBM designed the silicon chip and eMagin developed the organic stack and performed the back-end-of line processing and packaging. Each pixel is driven by a constant current source controlled by a CMOS RAM cell, and the display receives its data from the processor memory bus. This paper describes the OLED technology and packaging, and outlines the design of the pixel and display electronics and the processor interface. Experimental results are presented.

Time delay and integration imagers and their applications to image acquisition cameras

A family of experimental time-delay and integration (TDI) charge-coupled imaging devices has been designed and built using a minimally-modified logic/memory NMOS process. These imagers yield more favorable tradeoffs between image quality, speed, and illumination than conventional linear imagers and are suitable for high-speed scanning of color or monochrome documents at low illumination power. The design and construction of a prototype scanning camera using the 3072*32 TDI devices is also described. Intended for publishing applications, the camera is capable of capturing both monochrome and color images. At half-page document size, the scanning resolution is 300 pixels/in. Special color filters are used to produce colorimetric outputs. Both reflective and transmissive illumination are provided to scan both prints and transparencies of various sizes.<<ETX>>