Sakae Kimura

32.3: New Peeping Prevention Technology to Control Viewing Angle Properties of TFT-LCDs

New peeping prevention technology to control the viewing angle properties of TFT-LCDs has been developed. This technology can be applied to all kinds of LCDs, especially to the ones for PCs, cellular phones, ATMs and so on. In this technology, an additional LC panel in which the whole area is divided into two kinds of small visible domains of different LC alignment directions is used. The products, named VAC Filter™ or VACF™, have been put on sale in 2003 and have been applied to TOSHIBA TECRA M3 and so on.

Emission characteristics and surface composition of dispenser cathodes in realistic vacuum

Abstract The emission characteristics of three types of dispenser cathode, i.e. Ir coated, OsRu coated and uncoated have been studied under realistic vacuum. The cathodes were installed in electron guns normally used for CRT. The emission current was measured in dc method under controlled gas pressures of Ar, N 2 , or H 2 at 10 −9 to 10 −6 torr. In cases of Ar and N 2 , significant decrease in emission current was observed for each cathode. The onset pressure for the emission decrease was several 10 −8 torr for coated cathodes and several 10 −7 torr for uncoated cathodes. For coated cathodes, the Ir coated cathode has been confirmed to have greater tolerance to the gases than the OsRu coated one. In the case of the H 2 , no significant decrease in emission current was observed. The surface compositions of cathodes during and after sputtering by Ar ion were observed by SAM. The results showed the differences in the manner of sputtering away of Ba(−O) layer for three types of cathode.

Ir-coated dispenser cathode for CRT

A compact dispenser cathode has been developed for application to cathode ray tubes (CRTs). A cathode emitter, comprising BaO, CaO, and Al/sub 2/O/sub 3/ in a molar ratio of 4:1:1, was impregnated into a porous tungsten pellet. An intermetallic compound of tungsten and iridium was formed on the cathode pellet. Heater ratings were 6.3 V*0.2 A. Emission characteristics were measured by using color CRTs. As a result, a cathode peak loading of 15 A/cm/sup 2/ was ensured in the space-charge region. Furthermore, life tests with a peak loading of 7.5 A/cm/sup 2/ were conducted over 10000 h. The decrease in emission current after 10000 h was within only 10% of the initial value. Reliability of cathode performance was assured in terms of breakdown potential between the heater and the cathode, emission characteristics, life performance, grid emission, and the drift in cutoff potential. In addition, the effects of the coating thickness on the emission characteristics are discussed. >

Emission characteristics of dispenser cathodes with a fine-grained tungsten top layer

Abstract In order to improve the emission stability of the Ir-coated dispenser cathode under ion bombardment, a fine-grained tungsten top layer was applied on the substrate porous tungsten plug before Ir coating. The emission characteristics were studied after being assembled in a CRT gun. Cathode current was measured under pulse operation in a range of 0.1–9% duty. Remarkable anti-ion bombardment characteristics were observed over the range of 1–6% duty. The improved cathode showed 1.5 times higher emission current than that of a conventional Ir-coated dispenser cathode at 4% duty. AES analysis showed that the recovering rates of surface Ba and O atoms after ion bombardment were 2.5 times higher. From these results it is confirmed that the Ir coated cathode with a fine-grained tungsten top layer is provided with a good tolerance against the ion bombardment.