Since their inception during the Second World War in the simple gyro reflector gun sights of combat aircraft
such as the Supermarine Spitfire, HUDs have been developed to achieve ever greater capability and
performance, initially in military applications but in the final quarter of the last century for civil applications.
With increased performance and capability came increased complexity and an attendant steady increase in cost
such that HUDs in civil applications are only to be found in some large passenger and high end business jets.
The physical volume of current solutions also has a significant impact on where they may be fitted and this
paper discusses techniques and approaches to reduce the volume and costs associated with HUD implementation
thereby making the operational and safety benefits of HUD available to a broader range of applications in lower
LCOS (Liquid Crystal on Silicon) is a reflective microdisplay technology based on a single crystal silicon pixel
controller backplane which drives a liquid crystal layer. Using standard CMOS processes, microdisplays with
extremely small pixels, high fill factor (pixel aperture ratio) and low fabrication costs are created. Recent advances
in integrated circuit design and liquid crystal materials have increased the application of LCOS to displays and other
optical functions. Pixel pitch below 3 μm, resolution of 8K x 4K, and sequential contrast ratios of 100K:1 have been
achieved. These devices can modulate light spatially in amplitude or phase, so they act as an active dynamic optical
element. Liquid crystal materials can be chosen to modulate illumination sources from the UV through far IR. The
new LCOS designs have reduced power consumption to make portable displays and viewing elements more viable.
Also innovative optical system elements including image and illumination waveguides and laser illuminators have
been combined into LCOS based display systems for HMD, HUD, projector, and image analysis/surveillance direct
view monitor applications. Dynamic displays utilizing the fine pixel pitch and phase mode operation of LCOS are
advancing the development of true holographic displays. The paper will review these technology advances of LCOS
and the display applications and related system implementation.
D-ILA modulators and projectors based on LCOS (liquid crystal on silicon) technology have been developed. The compact reflection-mode modulators have resolution of up to 3840 x 2048 pixels for projection display applications including simulation and visualization. The Evans and Sutherland VistaView head tracked area of interest system has evolved from 1992 to incorporate many display improvements. The paper reviews D-ILA technology and the incorporation of D-ILA projectors into the VistaView system.
D-ILA modulators and projectors based on LCOS (liquid crystal on silicon) technology have been developed. The compact reflection-mode modulators have resolution of up to 2048 x 1536 pixels for projection display applications. Research projectors have demonstrated resolution of 3840 x 2048 pixels. D-ILA projectors feature high contrast and a close-spaced pixel structure that creates high quality imagery. The structure of the D-ILA will be reviewed and current performance of D-ILA projectors characterized.
The demand for more pixels in digital displays is beginning to be met as manufacturers increase the native resolution of projector chips. Tiling several projectors still offers one solution to augment the pixel capacity of a display. However problems of color and illumination uniformity across projectors need to be addressed as well as the computer software required to drive such devices. In this paper we present the results obtained on a desktop size tiled projector array of three D-ILA projectors sharing a common illumination source. The composite image on a 3 x 1 array, is 3840 by 1024 pixels with a resolution of about 80 dpi. The system preserves desktop resolution, is compact and can fit in a normal room or laboratory. A fiber optic beam splitting system and a single set of red, green and blue dichroic filters are the key to color and illumination uniformity. The D-ILA chips inside each projector can be adjusted individually to set or change characteristics such as contrast, brightness or gamma curves. The projectors were matched carefully and photometric variations were corrected, leading to a seamless tiled image. Photometric measurements were performed to characterize the display and losses through the optical paths, and are reported here. This system is driven by a small PC computer cluster fitted with graphics cards and is running Linux. The Chromium API can be used for tiling graphics tiles across the display and interfacing to users' software applications. There is potential for scaling the design to accommodate larger arrays, up to 4x5 projectors, increasing display system capacity to 50 Megapixels. Further increases, beyond 100 Megapixels can be anticipated with new generation D-ILA chips capable of projecting QXGA (2k x 1.5k), with ongoing evolution as QUXGA (4k x 2k) becomes available.
Users needs for more pixels in displays are starting to be met as manufacturers increase the native resolution of projector chips. Tiling several projectors still offers a solution to augment the pixel capacity of a display. However problems of color and illumination uniformity across projectors need to be addressed as well as the computer software required to drive such devices. We present a novel, compact, high-resolution, uniform, tiled projection computer display. All projectors are illuminated by a common light source, utilizing a fiber optic beam splitting system and a single set of red, green and blue dichroic filters. This ensures uniform illumination across the tiled projected images, a single color temperature, color balance and stability, with improved image uniformity. The display performance is characterized by photometric measurements. We investigate also spectral losses in the screen material. The utility of the new display system is illustrated by a scientific application in air-borne radar imaging for archaeology.
The use of liquid crystal displays in combination with projection is not new. However, this type of display is becoming even more prevalent than it has been in the past. A variety of such displays are currently available for commercial or even consumer use. In this paper the authors review a number of liquid crystal devices, also known as light valves, developed specifically for use in projection systems. These include not only analog-addressed devices such as the photoactivated liquid crystal light valve, but matrix-addressed displays as well.
A stereoscopic projection system for displaying 3-D video
information has been constructed using Liquid Crystal Light Valves
(LCLV5) . Presently most stereoscopic displays of video imagery use a
single CRT with a liquid crystal or PLZT shutter1'2 or use two CRT5 with
orthogonally polarized outputs3. The advantage of the first method is
only one CRT is needed and image convergence is not a problem. However,
whether passive or active glasses are used for the field-sequential
viewing, ghost images are formed due to the finite phosphor decay time1.
A dual CRT projector 3-D display has the advantage that passive glasses
can be easily employed with virtually no ghost images. The luminous
output of the projector, though, is reduced by half during the initial
In a Liquid Crystal Light Valve projector the output light is
linearly polarized in normal operation. Therefore a two-projector 3-D
stereoscopic system using LCLVs can be realized which has very low
intensity ghost images, high luminous output, and can be viewed with
passive glasses. This paper discusses some potential configurations of
such a projector and how a newly developed LCLV with improved time
response makes real-time 3-D imaging using this technology possible.