Abstract: A ceramic discharge vessel (8) for a high-pressure discharge lamp has a pin-like feedthrough (10) inserted in a plug (11) made from a composite material. The feedthrough (10) has been sintered directly into the plug (11) and is additionally sealed by covering the area, surrounding the feedthrough, of the plug's surface facing away from the discharge volume with a ceramic sealing material (7a).

Abstract: A ceramic discharge vessel (6) for a high-pressure discharge lamp (1) made from a sintered body of optically translucent polycrystalline alumina ceramic which is doped with only 100-800 ppm MgO, only 200-1200 ppm ZrO.sub.2 and only 10-300 ppm Y.sub.2 O.sub.3 (by weight). This improves the loading capacity and operating characteristics of the vessel and of the lamp.

Abstract: A high pressure discharge lamp having an extended life includes a discharge vessel 8, and a feedthrough 10 extending through a plug 11. A directly sintered connection is formed between the feedthrough 10 and the plug 11 wherein sealing material 7 is provided covering the area surrounding the feedthrough on the outer surface of the plug 11. The plug 11 is formed of a composite material whose thermal expansion coefficient lies between that of the ceramic vessel and of the metal feedthrough.

Abstract: An optical fiber connector for splicing a plurality of optical fibers integrally, including V-groove substrates each comprising V-grooves for setting optical fibers therein. Further, positioning standard surfaces arranged in parallel with a V-groove forming direction are formed in the substrates to enable stacking of the substrates on the basis of the positioning standard surfaces.

Abstract: Disclosed is an optical fiber connector for a plurality of covered optical fibers, including (a) a lower ceramics plate with a top plane surface having a plurality of V-grooves, each groove for respectively holding one fiber, (b) an upper plate, in spaced apart combination with the lower plate, for firmly holding the optical fibers in the lower plate grooves, and (c) a holder having two opposed end portions in which (i) a first cavity is profiled in the first end portion to accommodate the combination of the upper and lower plates, and (ii) a second cavity is profiled in the second end portion to accommodate the covered fibers, and wherein the first cavity has a connection portion proximate to an inner end of the second cavity, which connects the first and second cavities to provide a through passage for the fibers.

Abstract: A ceramic lid for sealing a semiconductor element and having a sealing surface which is to seal a semiconductor element within a recess of a ceramic package, by heating the recess with glass sealant and hermetically sealing the semiconductor element. The ceramic lid is made of alumina of high purity and to the sealing surface of the ceramic lid is applied a glass sealing aid which is pretreated at a higher temperature than the heating temperature for sealing the semiconductor element, before hermetically sealing the semiconductor element in the ceramic package. A method of manufacturing a ceramic lid for sealing a semiconductor element includes the steps of manufacturing the ceramic lid with alumina of high purity having a sealing surface with the recess of the ceramic package, wherein to the sealing surface of the ceramic lid is applied a glass sealing aid of 5-30 .mu.m in thickness onto a sealing surface of the ceramic lid with the ceramic package.

Abstract: Polycrystalline translucent alumina having an average grain size of alumina crystal grain being not smaller than 20.mu. and an average surface roughness of the fired body being not larger than 1/10 of the maximum grain size of alumina crystal grain and capable of being used for an envelope of a high pressure vapor discharge lamp, which is produced by shaping alumina composition powders consisting mainly of alumina into a given shape, primarily firing the shaped body under vacuum or in an atmosphere of hydrogen gas or dissociated ammonia gas at a temperature within 1,500.degree. C. and then secondarily firing the primarily fired body at a temperature of 1,650.degree.-1,900.degree. C., at least the temperature from 1,400.degree. C. to 1,700.degree. C. being raised at a rate of not lower than 200.degree. C./hr.