55 inch High Definition Projection Display

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.