A luminaire comprises a light source and a reflector which has an opening for emitting light and an apex opposed the opening, and which reflects light emitted from the light source in a desired direction. The reflector having a first area at the intermediate portion between the opening and the apex thereof consisting of a plurality of reflecting surface units with inclined surfaces located at both...

An electron gun having a cathode of a lanthanum hexaboride single crystal is disclosed in which the axis of the cathode is set to such a crystal orientation that the electron beam has two intensive emission regions which are asymmetrical with each other in intensity. In the electron gun, even at a low heating temperature of the cathode, a single spot of an image by the electron beam of a more inte...