Hong Choi, Ollie Woodard, Bor-Yeu Tsaur, Brenda Dingle, Edward Yung, Jeffrey Greiman, Ngwe Cheong, Martin Metras, Wen-Foo Chern, Jason Lo, Pin Anupongongarch, Murshed Khandaker, Dave Costa, Frederick Herrmann, Hiap Ong, Colin Reese
We report the progress in full-color 0.97-inch-diagonal SXGA and 0.57"-inch-diagonal XGA active matrix
liquid crystal displays. The circuits for these displays are fabricated on 8-inch silicon-on-insulator (SOI) wafers,
which are then transferred to glass wafers to produce transmissive liquid crystal displays. Significant power
savings and display performance improvements have been made with innovations in display architectures and
the use of indium tin oxid (ITO) pixels. The new thin efficient backlight with improved color spectrum also
contributes to lower power consumption and better color gamut. The Mantech program for the SXGA display
has enabled the processing of many wafers to resolve various production issues, which will result in
substantially higher yield for the SXGA microdisplays.
We report progress in developing a 0.97-in diagonal AMLCD with a full color SXGA resolution. A 1280×1024×3 dot
array was developed with integrated color pixel filters to create an SXGA color pixel array. These displays are
fabricated on 8-inch SOI wafers and transferred to glass wafers to produce transmissive liquid crystal displays.
Improvements have been made in this AMLCD to bring the fabrication process to manufacturing. Fabricating a 3.9
million pixel dot display on a 1-inch die required a new display design and fabrication in an 8-inch wafer line. The 8-inch process provided enhanced process capabilities and tighter design rules to achieve good performance and
reasonable starting yields.
An ASIC driver and ultra thin efficient backlight were developed to miniaturize the display module and to reduce total
power to < 750mW for soldier mounted applications. Total package size is less than 0.5 in3. The ASIC will also drive
Kopin SVGA and VGA color displays singly or in pairs for binocular applications.
An end-to-end 8-inch wafer process was established at the wafer foundry and at Kopin. A 3-year manufacturing
technology insertion program (Mantech) has begun to optimize the 8-inch line processes and the SXGA color display.
Meeting yield and performance goals will reduce display cost and enable systems performance goals.
Key results include vivid, high-resolution color, wide viewing angles and low power operation. Performance data and
specifications will be presented.
We report progress in developing high-contrast, wide symmetrical viewing angle multi-domain vertical alignment (MVA) AMLCD's with a full color SXGA resolution (1280x1024x3 dots). These MVA displays are fabricated with a smooth surface and without either protrusions or an ITO slit-pattern geometry. Intrinsic fringe fields in each pixel control the LC alignment and formation of domains. We have achieved contrast ratios greater than 1000, and symmetrical viewing angles greater than 120 degrees.
A 3840x1024 dot array was developed with integrated color pixel filters to create a 1280x1024 color pixel array. The pixel design, display driver operation, and color mosaic were optimized for MVA operation. Pixel shapes were developed to control domain formation and to maximize light transmission using 3-D modeling and test displays. New LC materials were investigated to increase transmission and to minimize voltage drive requirements.
Improvements have been made in this MVA liquid crystal display to bring the fabrication process closer to manufacturing. Key results include striation-free displays with spun-on polyimide alignment layers, elimination of boundary stick via pixel design, overall viewing angle improvement with an MVA-matched wide viewing polarizer, and transmission improvements with high delta n LC, cell gap, driving mode, LED and BEF backlight combination. Performance data and specifications for Kopin's color filter MVA and TN displays will be presented with reference to military, industrial, and commercial applications.
Kopin's miniature Active Matrix Liquid Crystal Displays (AMLCD's) are used in military head mounted and sensor viewer applications. These low power, ruggedized displays operate from -37°C to +65°C with excellent imaging characteristics and reliability. Kopin and the US Army Night Vision and Electronic Sensors Directorate (NVESD) are developing high resolution, full-color displays for day/night operations and image fusion applications. Kopin has begun the development of a miniature, spatial color SXGA display using a new Kopin design and process to fabricate multi-domain vertical alignment (MVA displays. The MVA display offers a normally black screen, very high contrast ratio and wide, symmetrical viewing-angle. MVA monochrome SXGA, monochrome VGA (640x480 pixels) and color filter VGA displays have been demonstrated. A 0.97" diagonal, color filter SXGA MVA display is the goal for this program.
The patented MVA process uses a simple fabrication process that makes use of the intrinsic fringe field in each pixel to control the LC alignment. Contrast ratios greater than 1000:1 and 120-degree symmetrical viewing angles are routinely achieved. The power-off state or failed state on MVA displays is black, which reduces the visibility of defective pixels. The normally black AMLCD is the preferred mode for night military operations / applications, and see-though Head Mounted Display (HMD) optical designs.
Performance data and specifications for Kopin's monochrome and color filter MVA displays will be presented with reference to military (HMD and weapon sight), industrial, and commercial applications. Application extensions that utilize the new MVA color filter technologies developed will be highlighted.
Kopin's miniature Active Matrix Liquid Crystal Displays (AMLCD's) are rapidly becoming the display technology of choice in a wide range of military head mounted and sensor viewer applications. These low power, ruggedized displays operate from -37°C to +65°C with excellent imaging characteristics and reliability. Kopin and the US Army Night Vision and Electronic Sensors Directive (NVESD) are co-operatively developing high resolution, full-color displays for day/night operations and image fusion applications. Kopin is leveraging the successful development of its monochrome SXGA (1280 x 1024) AMLCD to develop a color SXGA display and a color SVGA (800 x 600) display. Color technology approaches evaluated for these new products included color filters, frame sequential color, binary optic phase plate spot sequential color, and diffractive optic column sequential color. These approaches all involve frame sequential operation with the exception of color filters. A generic color frame sequential mode was selected for the SXGA display design that will allow operations of all frame-sequentially based approaches. This display facilitates color technology changes and upgrades by replacing the backlight assembly. The color filter approach was selected for the SVGA display. Both color technologies are used for Kopin commercial display products. Performance data and specifications for Kopin's displays will be presented with reference to military (HMD and weapon sight), industrial, and commercial applications. Analytical results and data from color approaches investigated will be presented and compared. Application extensions that utilize the new color technologies developed will be highlighted.
A miniature 1280 by 1024 transmissive active matrix liquid crystal display (AMLCD) was developed for the helmet-mounted display in the RAH-66 Comanche helicopter. To meet the stringent environmental and optical performance requirements, improvements were made in the AMLCD's operating temperature range, viewing angle, pixel size, and transmission. These features were combined with technology previously developed to provide uniform gray scale, rapid optical response times, and ultra high-brightness imagery for the combination of high-resolution FLIR imagery and flight symbology viewable in daytime environments.
Ronald Gale, Frederick Herrmann, Jason Lo, Martin Metras, Bor-Yeu Tsaur, Alan Richard, David Ellertson, Kuojoing Tsai, Ollie Woodard, Matthew Zavracky, Michael Presz
A miniature 1280 by 1024 transmissive active matrix liquid crystal display (AMLCD) was developed for the RAH-66 Comanche helicopter head-mounted displays and other military applications. The display has an active area of 15.4 mm by 12.3 mm with a diagonal of 19.7 mm (0.77 inches). The display has a 12 micrometer pixel pitch, yet a clear optical aperture of over 30% was achieved by using a 0.8 micrometer CMOS design rule for the active-matrix circuit fabrication. The fabrication process used was similar to that of Kopin's commercial CyberDisplay AMLCD's, which produces high performance, high reliability devices. To achieve low temperature operation to -40 C, the display was designed with an integrated thermal sensor to allow control of a heater. Display test results include contrast ratios over 100, continuous gray scale, fast response times for 60 Hz operation, and the ability to show both gray-scale images and symbology at display luminescence levels over 2,000 foot- Lamberts brightness. This latter result will enable this display to be used in systems with full sunlight readability requirements. The design, fabrication, and characterization of this display are discussed.
A 2100 line-per-inch, active matrix liquid crystal display technology has been developed. Functional displays were produced and demonstrated with contrast ratios of up to 50:1. The achievement of a 12 micrometers pixel pitch results in only a 1.5 inch diagonal for the 2560 by 2048 pixel array of 5.24 million pixels. Display drive electronics integrated into the periphery areas around the pixel array include row addressing, column select/video data loading, and clock circuits. External electronics requirements are reduced and the display connector contains only video, clock and power lines. The active matrix TFT's and peripheral circuits contain over 5.3 million transistors, the complexity of a large integrated circuit. Six display circuits were fabricated on each 6 inch Silicon-On-Insulator wafers using CMOS IC processes. The single crystal silicon circuits readily achieve the high speeds required to drive these large pixel arrays at a 60 Hz frame rate. The thin x-Si layer containing the display circuits was transferred from the silicon wafer to glass in the manufacturing process. This approach leverages mature wafer-based IC processing for display manufacturing.
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