Projectors based on polymer-eNCAPsulated liquid crystals can provide bright displays suitable for use in conference rooms with normal lighting. Contrast is generated by light scattering among the droplets, rather than by light absorption with crossed polarizers. We have demonstrated a full-color, compact projector showing 1200 ANSI lumens with 200 watts of lamp power - a light efficiency of 6 lumens/watt. This projector is based on low-voltage NCAP material, highly reflective CMOS die, and matched illumination and projection optics. We will review each of these areas and discuss the integrated system performance.
Recently there has been much interest in a new polymer nematic dispersion technology, often called as NCAP, PDLC, PNLC, LCPC, etc., since projection displays using this technology have been shown to produce much brighter display images than projectors using conventional twisted nematic (TN) lightvalves. For commercializing projection displays based on this polymer nematic dispersion technology, the new materials must not only meet various electro- optic requirements, e.g., operational voltage, `off-state'' scattering angle, voltage holding ratio and hysteresis, but must also be stable over the lifetime of the product. This paper reports recent progress in the development of NCAP based projection displays and discusses some of the key commercialization issues.
Prototypes of projection displays based on dispersions of liquid crystal in polymer matrices are beginning to appear. The principle of operation depends on electrically switchable light scattering. They are potentially much brighter than current cathode ray tube (CRT) or twisted nematic liquid crystal (TN LC) cell based displays. Comparisons of efficacy and efficiency show this. The contrast and brightness of such displays depend on a combination of the f- number of the projection system and the scattering characteristics of the light valve. Simplified equations can be derived to show these effects. The degree of scattering of current NCAP formulations is sufficient to produce good contrast projection displays, at convenient voltages, that are around three times brighter than TN LC projectors because of the lack of polarizers in the former.
A serious concern in the fiber optics industry is the low strength of fiber in connectors, frequently as low as 10% of that of the original fiber. The main reason for this low strength is that the stripping and termination procedure exposes and abrades the bare glass surface. Several fiber manufacturers have recently introduced a fiber construction which can greatly improve the mechanical reliability of fiber in connectors. The actual constructions from the various manufacturers vary in detail, but all have one common feature, a primary organic coating which remains in place when the secondary coatings are removed in preparation for terminating the fiber into a connector. In order for connectors to be successfully glued to this coating, the coating must be hard and well adhered to the glass surface. The coating is generally thin, typically about 10 pm. With such a coating the bare glass surface is never exposed when the fiber is stripped and terminated, and thereby retains its strength and mechanical reliability. Data will be presented on the strength of terminated fiber with and without such permanent, primary coatings.