Akio Ohkoshi

Laser‐addressed liquid crystal light valve with dichroic dye added as a laser beam absorber

A dichroic dye was added to smectic A liquid crystals as an absorber of laser energy to eliminate the need to conduct heat from an external absorber to the liquid crystal layer. It was found that the dichroic ratio of the added dye is an important factor in the recording mechanism of the liquid crystal. The resolution of the written image was improved by doping with a dye having a large dichroic ratio.

A Wide-Deflection Angle (114°) Trinitron Color-Picture Tube

Black and white picture tubes, with the exception of certain special purpose tubes, are currently all nearly wide-angle deflection types. Similarly, wide deflection angles are now being adopted in the color picture tube field. Since the principle of the color picture tube is far more complex than that of the black and white tube, a sophisticated production technology is necessary, and consequently production techniques of wide deflection angle color tubes are less advanced at present. Companies producing the conventional 3-gun shadow mask tube recently have successively announced improvement of their mass production technology and have greatly changed the design of the tube itself in their efforts to achieve ease of production comparable to that of the 90°deflection tube. Since their principal objective is to make the picture tube thinner, achievement of picture quality at the same level as in the 90°deflection tube is one of the problems.

A Compact Flat Cathode Ray Tube

Of all the display devices which have been so far proposed, the cathode ray tube still offers a number of advantages of its own: high luminous efficiency, easy addressing a wide dynamic range of brightness, and a well-established manufacturing process. The conventional CRT, on the other hand, has the disadvantages of requiring a high voltage and of having considerable depth. Although recent advances in electronic circuit technology have somewhat offset the former drawback, it is undeniable that the CRTs geometry makes its use as a display devices in certain applications difficult.

A New TV Receiver Employing A Beam-Index Color CRT

The considerably more complex electronic circuits which seem to be required by a beam-index color display system, as compared with a conventional shadow mask system, have for many years offered an irresistable challenge to circuit designers. The reward of a successful design is the several advantages inherent in the beam-index system which have been previously discussed.1-31-3

A New 30 V" Beam-Index Color Cathode Ray Rube

The advantages of a beam-index color CRT over a conventional color CRT with a color selection mechanism have been discussed elsewhere.1-6 Despite these advantages, beam-index TV receivers have never been mass-produced, because of the complexity of the electronic circuits, difficulties with the index phosphor screening process and the stringent requirements for a narrow electron beam spot.

New Color Video Projection System with Glass Optics and Three Primary Color Tubes for Consumer Use

Approximately forty years ago, the first commercial video projection system was introduced. Until quite recently all projection systems were designed for institutional use only. In 1972, however, the Sony Corporation unveiled a projection system1) for consumer use at the International Convention and Exposition sponsored by IEEE. Since that time, as the quality of large-screen pictures improved, and their price fell, the many advantages of a large-screen picture over a conventional color TV picture have created a new consumer electronics market. The development of a projection system for consumer use has been made possible by recent advances in cathode-ray tube and electronic circuit technology. In addition to these essential advances, many new techniques have been developed in, for instarnce, projection optics and screen fabrication.

Achievement of High Picture Quality in Color CRTs with the Beam-Scan Velocity Modulation Method

The aperture compensation method is visually very effective, because it emphasizes the contours of the picture image by preshooting or overshooting the electron beam current. The picture image is, however, influenced adversely by the large beam spot resulting from the increase of the beam current at the contours. Consequently, this increase in beam spot size results in suppression of sudden brightness changes. The effect may be very clearly seen as the increased band width of a window pattern video signal, for example.

A New Optical Videodisc System with One Hour Playing Time

A series of papers proposing a possible format for reflection-type optical videodisc systems was published in 19761-3. Principal parameters of the format (with NTSC standards) are as follows: the disc rotation speed is 1800 rpm, the track-to-track pitch is 1.67¿m, and the playing time is 30 minutes from one side of a 12-inch-diameter disc. A direct frequency modulation of the composite NTSC video signal is employed, with the attractive feature that the full extent (4.2 MHz) of NTSC luminance bandwidth can be retained in this format.