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A colour TV projection system contains three fast-switching reflective liquid crystal light valves (LC-LV) exhibiting a large aperture which enhances brightness to 500 lux on a 1 m 2 screen, inserting a 250 W projection lamp. The 400 200 pel a-Si:H thin-film transistor addressed LC-LVs are designed as reflective quarterwave plates operating in the hybrid aligned nematic mode with a turn-on...
In the first part of the three-paper series on light-valve projection with metallized viscoelastic control layers, the technologies for producing suitable layer systems as well as the observed performance of such light modulators are described. Optimum conditions for elastomer preparation and gel-layer formation by means of spin coating are given. Before metallization in a multistep vacuum evaporation...
First the diffraction efficiencies of various light-valve arrangements are compared. The arrangement based on total internal reflection is one of the best of these. It requires only around one-quarter of the control-layer deformation that would be necessary for the same light output with a single-transmission arrangement. In the total-internal-reflection arrangement, the large angle between the...
A novel optical system is proposed to polarize white light and illuminate a rectangular 16/9 format. It is designed for LCD video projectors and improves the luminous efficiency provided a very short arc lamp is utilized. An analysis based on the geometrical extent concept predicts that this polarizing optical system is well suited to small-size LCDs.
In the second part of this three-paper series, the design and the fabrication of monolithic active matrices for addressing metallized viscoelastic light-valve control layers are described together with the required external electronics. The active matrices were fabricated by means of standard silicon CMOS technology. Special matrix features are signal-handling capabilities of 30 V, optimized surface...
The advantage of schlieren optical large-screen projection is its ability to control a high light output power and to create bright images. The imaging element is a phase modulator which can be implemented using liquid crystal (LC) technology. In this contribution the operating principle and optical properties of three different types of phase modulators, i.e. a tandem cell, a modulator with a twisted...
In the final article of this three-part series, the optical system for a light-valve projector with metallized viscoelastic control layers and active-matrix addressing is described. The requirements of one single light source, three identical light modulators, and one projection lens for the three colour channels lead to design specifications that were implemented in a laboratory setup with closely...
In this short introduction to the special issue, the history of light-valve projection for large-screen displays is briefly outlined, and the present status is discussed. A number of seminal publications, especially those from the early years, are listed for further reference.
A software-based simulation system for full-colour thin-film electroluminescence (TFEL) displays is presented. The developed system provides tools for simulating the visual appearance of full-colour TFEL displays on a high-resolution shadow mask colour cathode-ray tube. The visual appearance of TFEL colour display configurations with different phosphors, colour cell geometric layouts, resolutions...
Recent neuroscientific findings concerning the relationship between the perceptive, cognitive and linguistic aspects of colour suggest that colour concept retrieval would be enhanced by free colour naming or by the use of natural associations between colour concepts and colour words. To test this hypothesis, we had subjects give their own free associations to a set of 35 colours presented on a display...
This paper is concerned with the combined influence of image motion and image resolution on (perceived) sharpness. We examined these effects for both a fixation and a pursuit condition: only in the latter case was it possible to follow the object in motion. In the fixation condition we presented various resolution levels, and image velocities up to 5.3 deg/s. We found that sharpness decreases with...
The Advanced Media Unit at BT has been investigating the possibility of producing 3D video telephones. These would have to be usable with no disadvantages when compared with conventional 2D video telephones. This precludes the use of glasses-based systems. We have selected an autostereoscopic system based around a lenticular sheet as the most appropriate for our requirements. Ray-tracing models...
This paper discusses the miniaturization of display devices that are capable of displaying information from VGA and SVGA as well as video movies and TV images. We conclude that miniature CRTs are suitable display devices for mounting on helmets, headbands and spectacles. We then developed the 0.6in miniature CRT based on new concepts in the design of the electron gun and the phosphor screen. The...
An electronic pseudocolour encoder based on the principle of the optical method is described. The system can perform pseudocolour encoding on-line. A compact handheld system consisting of a monochrome CCD camera, electronics and a liquid crystal display in a housing has been constructed.
The performance of a colorimetric calibration method for colour CRT monitors has been investigated experimentally for six monitor types representing different quality levels. The colour of luminous patches in the presence of different border and background colours on the screen was measured. Systematic deviation from the calibration method described in CIE Technical Report, Guide to Characterizing...
This paper describes a study in which 30 participants, all of whom had reported symptoms of malaise during their first immersion in virtual reality, were re-immersed in the virtual reality system on three further occasions in order to investigate the possibility that repeated immersions may produce a decrease in malaise as participants adapt to immersion in virtual reality. It was found that 18 of...
This paper discusses the usability problems of acoustical fishing aids in small fishing vessels with particular reference to interpretation and comprehension of data. After a brief account of how the problems arise, some design principles are derived which are then applied, by means of an heuristic analysis, to a typical display. The paper concludes with a discussion of how, in the last year or...
The purpose of this study was to investigate the use of monoscopic and stereoscopic depth cues for spatial instrument design. Ten volunteer subjects judged the depth and altitude separation between two computer-generated objects located above a ground plane using either a stereoscopic or perspective display. The depth cues manipulated in the study were shadows, a texture gradient, droplines from...
This paper discusses the problems of achieving grey scale in ferroelectric liquid crystal (FLC) devices due to the lack of symmetry in the switching schemes used (in comparison with anti-FLC devices where alternate cycles are of opposite polarity). Two interesting schemes are presented which allow recovery of symmetry in the switching of FLCs. These use either stroboscopic illumination, or a second...
The types of instruments used for colour measurement of self-luminous and surface colours, and the choices available for their optical design, are described. Guidelines are given for selection of measurement conditions appropriate to different measurement applications. The important steps in calibrating and verifying the performance of colour-measuring instruments are described and the standards...
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