The record of large screen displays in military C3I applications is a spotted one. The combination of immature equipment and state-of-the-art requirements have often resulted in unattained required performance, excessive costs and an inordinate number of maintenance actions. Representative functional requirments for large screen displays in C31 applications are developed. Critical large screen display (LSD) performance metrics are defined and commentary provided as to the contrast between these metrics and contemporary technical specifications for available large screen products. Future trends for this class of equipment are identified.
The replacement of the large center screen displays at the Houston Mission Control Center (MCC) is complicated by the unique requirements of the Flight Controller user. These requirements demand a very high performance, full color projection system capable of the display of high resolution text, graphics and images produced in near real time. This paper describes the current system to he replaced, the replacement system requirements, the efforts necessary to procure the major element of this system (the projector) for the government, and how the new capabilities are to be integrated into the existing MCC operational configuration.
Aircraft, marine and armament trainers often use out the window simulated images in order to provide realistic images to the trainee. Juxtaposition of several images matched side by side and/or top to bottom ca be used to provide a wider field of view (F0V). Videorama makes use of a newly patented technique that allows up to eight channels of TV projectors and/or large screen direct view displays, used in any combination, to be adjusted from a single touch panel entry remote alignment control unit to form a seamless composite image.
This paper describes the use of a metric called modulation depth to successfully characterize the resolution of any large screen display (LSD). In addition, a measurement technique was developed to provide for an accurate and repeatable determination of modulation depth. Resolution measurements made on commercially available LSDs with this technique demonstrate its utility in both development and production environments. Finally, a linear systems analysis calculates the modulation depth seen by the observer as a function of distance from the projection screen. This calculation is then related to the actual measurements obtained from the LSDs. As a result of this work, the resolution metric and associated measurement technique should form the basis for an LSD industry standard.
The needs for large screen displays is increasing and with the introduction of higher quality picture, the demand will grow even more. Larger size picture tubes are becoming very common now in today's industry. But there are limitations in the direct view tube technology because of glass strength, weight, performance and cost. The CRT projection system was developed in order to achieve a much larger picture with easier technology and lower cost. At the early stage of CRT projection development, the obtained picture was only a very dim, vague and low contrast one. Intense investigations were done in this area and many improvements were accomplished. The improvements are not limited only to the tube, but also to the optical system (lens and screen) and its system design. As a result, we have achieved very bright picture having good contrast. Total performance of latest projectors is even better than direct view tube systems. In the coming era of HDTV, displays have to have much larger screen and higher resolution. We think the CRT projection system will play a big role in this field.
High-definition TV is an expected next generation television broadcasting system, and the broadcast of which will start in 1990 in Japan. The system is also expected for the use of industrial application. For these requirement , 54-inch, 110-inch, and 200-inch projection displays have beep developed. The horizontal resolution of 1000 TV lines, the peak brightness of 410 cd/m2 (54-inch), and the contrast ratio of more than 100 for rear projection displays can be realized by the development of 9-inch dual focusing projection tube, high resolution projection lens, fine pitch high contrast rear screen and large output horizontal deflection circuit etc.
Toshiba has developed a 55-inch high definition rear projection display with high luminance and resolution, with an expanded viewing angle, not only in the horizontal direction but in the vertical direction as well. In Japan, it is foreseen that the high definition television will begin spreading through use in CATV and video displays at exhibitions, and in small theaters, rather than in homes. These applications would require bright display with a large screen and wide viewing angle, so that they can be seen by larger number of viewers. Achieving a wide viewing angle suitable for these purposes, however, was a difficult matter in a projection type display development. Conventional rear projection displays use a 2-layer acrylic sheet screen, consisting of a lenticular lens and a Fresnel lens. This structure is only effective in expanding the horizontal viewing angle. Toshiba's newly developed display employs a third screen inserted between the two other screen sheets, which increases the vertical viewing angle by 26 %. Furthermore, the electronic beam diameter of the projection tube has been reduced by 20% resulting in a high resolution of 1000 TV lines. To obtain high luminance, the luminous efficiency of the green phosphor has been improved by 20%. As a result, the peak luminance of the picture reaches 125ft-L or more, which is the highest value for any display currently available for professional HDTV purposes.
NEC has developed the Multi-Sync Video/Data Projector which responds to growing requirements for large screen display. The NEC Multi-Sync System is capable of handling signals from various sources such as Personal Computers,HDTV,and other video generating equipment. Therefore, this Video Projector is so designed to automatically lock to horizontal frequencies from 15kHz to 36kHz and vertical frequencies from 38Hz to 100Hz. The NEC Digital Convergence System is the culmination of numerous technologies implemented in this projector. With this combined technology the convergence can be adjust with super accuracy by using 117 (13H*9V points) independent fine tunable adjusting points on a screen. The NEC Automatic Convergence System has also been developed which adjusts convergence automatically within 5 minutes with an accuracy of 0.3 line of scanning lines.
We have developed a new optical system for projection television to achieve high luminance and excellent image quality with light weight compact size cabinet. This optical lens system has a hybrid structure employing four plastic and one glass lens. By introducing an aspherical surface on both sides of all plastic lenses, we have achieved an improvement of image quality over the entire screen. The lenses controlled to be thinner in this design method simplifies molding. Plastic lenses are imperfect in that they are subject to focus drift due to changes in ambient temperature. To minimize this effect, glass is employed in the main power lens. Furthermore, the lenses are arranged in such a way to eliminate the drift by optimum use of power distribution. This system has a short focal length and thus employs a single-reflection optical path system, ensuring a compact cabinet size and a reduction of chromatic abberation which cannot be achieved by simply introducing aspherical lenses. The design reduced the focal length from our conventional figure of 156 mm to 86 mm. Despite the large aperture FN0 of 1.0 an approximate increase of 30% in the MTF value has been achieved. The image quality is perfectly maintained over a temperature fluctuations of ± 20°C. Overall weight of the lens assembly has been reduced by 1/5. The system has been in operation in Pioneer 40 and 50 inch T.V. sets since 1987. The system is applicable to and essential for the future HDTV.
Since the development of the liquid crystal display (LCD) projector, several features have been improved to realize better quality and performance. The two points listed below have achieved especially satisfying levels: 1. efficiency of utilization of white light source 2. color uniformity As a result an LCD projector with a brightness of more than 70 lumens, and color uniformity characterized by a variation of u' & v' within 0.04 at the peak white level has been developed.
A review of spatial light modulator technologies is presented, including the description and performance parameters of the main devices, and their main applications for optical information processing. The various performance trade-offs and their impact on emerging new technologies and future trends of spatial light modulators are discussed.
Culminating a research and development project spanning many years, StereoGraphics Corporation has succeeded in bringing to market the first field-sequential electronic stereoscopic projector. The product is based on a modification of Electrohome and Barco projectors. Our design goal was to produce a projector capable of displaying an image on a six-foot (or larger) diagonal screen for an audience of 50 or 60 people, or for an individual using a simulator. A second goal was to produce an image that required only passive polarizing glasses rather than powered, tethered visors. Two major design challenges posed themselves. First, it was necessary to create an electro-optical modulator which could switch the characteristic of polarized light at field rate, and second, it was necessary to produce a bright green CRT with short persistence to prevent crosstalk between left and right fields. To solve the first problem, development was undertaken to produce the required electro-optical modulator. The second problem was solved with the help of a vendor specializing in high performance CRT's.
For the foreseeable future the mainstay of high resolution display will be the Cathode Ray Tube (CRT). There is still substantial improvement in performance possible from the CRT, particularly regarding Projection Display. Increases in performance will come not only from advances in materials, but also from better Electro Optical systems engineering. This paper presents one approach.
Studies completed during the past two years at the Operations Training Division of Air Force Human Resources Laboratory (AFHRL/OT), Williams AFB, provide comparative data on a single light-valve projector (SLVP) using one xenon arc source and a multiple light-valve projector (MLVP) using two sources and two light valves with common final optics. Spectral energy distributions (SEDs) of light-valve primaries are continuous distributions without the spikes characteristic of some CRT phosphor emissions. Equations relating digital RGB codes to color output must take into account an unavoidable "dark field haze" resulting from the internal optics of these projectors. This "haze" can be considered as a constant additive factor analogous to ambient illumination on a cathode-ray tube.
This paper reflects on past laser projects to display vector scanned computer graphic images onto very large and irregular surfaces. Since the availability of microprocessors and high powered visible lasers, very large scale computer graphics projection have become a reality. Due to the independence from a focusing lens, lasers easily project onto distant and irregular surfaces and have been used for amusement parks, theatrical performances, concert performances, industrial trade shows and dance clubs. Lasers have been used to project onto mountains, buildings, 360° globes, clouds of smoke and water. These methods have proven successful in installations at: Epcot Theme Park in Florida; Stone Mountain Park in Georgia; 1984 Olympics in Los Angeles; hundreds of Corporate trade shows and thousands of musical performances. Using new ColorRayTM technology, the use of costly and fragile lasers is no longer necessary. Utilizing fiber optic technology, the functionality of lasers can be duplicated for new and exciting projection possibilities. The use of ColorRayTM technology has enjoyed worldwide recognition in conjunction with Pink Floyd and George Michaels' world wide tours.
Over the past ten years, a number of projects for motion picture and theme park use have been produced using synthetic computer generated imagery. These images have been produced for the media of standard 35mm Academy aperture, full aperture, VistaVision, 65mm five perforation, and dual strip 65mm 3D stereoscopic.
Advances in performance of projection CRTs, electronic processing and lens and screen technology have brought CRT projection TV systems into a rapidly growing number of consumer homes. A reduction in cost of these systems will further stimulate their application. Also a demand exists for improved definition display systems; a number of new standards for improved definition TV have been proposed in recent years . A large video screen ( > 37") enhances the emotional link with the viewer; more image details can be resolved by human vision. Projection TV technology can combine the attractiveness of a large TV screen with good picture quality and ease of installation. Two projection technologies, CRT projection and LCD projection, have been developed for the purpose of consumer TV display.