Abstract: The present invention is directed to a light controlling sheet in use for optical indicators which comprises louver elements including an arbitrary pattern of walls which are parallel to each other and so opaque as to absorb incident light; transparent layers for permitting the incident light to pass therethrough and light reflection layers for reflecting the incident light. The transparent layers and the light reflection layers are mutually interposed between the walls of the louver element. The oblique light from the light source strikes the side surfaces of the walls, while the substantially parallel light from the light source passes through the transparent layers toward the observer. The extraneous light is reflected at the front surface of the light reflection layers so that the light controlling sheet is bright and stands out clearly.

Abstract: The disclosure relates to a light controlling sheet for use with indicators which includes a louver element including an arbitrary pattern of walls which are parallel to each other and opaque so as to absorb light, and an electrically conductive film which is mounted on one surface of the louver element. This film is porous so that the light from a light source may penetrate. The oblique light strikes the opaque walls of the louver element and is absorbed in the walls, while the substantially parallel light is permitted to pass through the space or transparent portion betwee the walls. The electrically conductive film not only acts as a protective cover for the louver element but also shields unwanted electromagnetic wave.

Abstract: The present invention is directed to a light controlling sheet in use for optical indicators which comprises louver elements including an arbitrary pattern of walls which are parallel to each other and so opaque as to absorb incident light; transparent layers for permitting the incident light to pass therethrough and light reflection layers for reflecting the incident light. The transparent layers and the light reflection layers are mutually interposed between the walls of the louver element. The oblique light from the light souce strikes the side surfaces of the walls, while the substantially parallel light from the light source passes through the transparent layers toward the observer. The extraneous light is reflected at the front surface of the light reflection layers so that the light controlling sheet is bright and stands out clearly.

Abstract: A fluoride flux for silver brazing comprises an iron powder, a cobalt powder, a nickel powder or a copper powder which has an average diameter of 1-100.mu. in a flux having a main component such as an alkali metal fluoride, an alkali fluoroborate, an alkali metal chloride, an alkali metal borate, etc..

Abstract: Substrates made of a metal or an alloy are bonded by coating a brazing flux incorporating a metallic powder or a metal compound powder on the surface of the substrate having a melting point of higher than 700.degree. C.; and heating them at a temperature higher than a melting point of the flux but lower than a melting point of the metal of the metallic powder or the metal compound powder whereby a molten crystallization and a mutual diffusion are caused between the substrates and the metal activated by the molten flux.