Abstract: In an electroluminescent element, a first electrode having first and second opposite surfaces is layered on a substrate so as to contact the substrate on its first surface. A luminescent layer containing a light-emitting layer is layered on the first electrode so as to contact the second surface of the first electrode. A second electrode having first and second opposite surfaces is layered on the luminescent layer so as to contact the luminescent layer on its first surface. The second surface of the second electrode is at least partially exposed. A first terminal is provided on the second surface of the first electrode at a portion that does not contact the luminescent layer. A second terminal is partially formed in the exposed portion. At least one of the first and second electrodes is transparent. The first and second terminals are connected to a power source.

Abstract: An optical device has an incident surface and a light exit surface located at an opposite side from the incident surface. The light exit surface defines a plurality of projections. The projections project away from the incident surface. Sections of the light exit surface that define projections include side faces of pyramids. Each of the pyramids has a bottom that is an imaginary plane substantially parallel to the incident surface. The side faces of each pyramid are slopes. At least one of the slopes is inclined at a range greater than 17° and less than 60° relative to the normal to the incident surface.

Abstract: A light extracting sheet is provided on a light extracting surface of an organic EL device. A prism sheet is provided on the light extracting sheet. The light extracting sheet has a first incident surface contacting the light extracting surface and a light exit surface located at an opposite side from the first incident surface. The light exit surface defines a plurality of first projections. Each of the first projections is pyramid. The prism sheet has a second incident surface that is substantially parallel to the light extracting surface and a light exit surface located at an opposite side from the second incident surface. The light exit surface defines a plurality of second projections. Each of the second projections is pyramid.

Abstract: An optical waveguide includes light admitting portions and a light emitting portion. Each light admitting portion admits light from a point light source. The light emitting portion emits light admitted by the light admitting portions. Each light admitting portion has an incidence portion. Each incidence portion includes incidence planes each extending in the width direction of the light admitting portions, and V-shaped grooves, which are alternately arranged. Each light admitting portion has a pair of flat reflection planes, which extend between the corresponding incidence portion and the light emitting portion. The distance between the reflection planes in each light admitting portion increases from a side opposite from the light emitting portion toward the light emitting portion. Therefore, the light emitting efficiency of the optical waveguide is improved, and brightness unevenness created the vicinity of each point light source is reduced.

Abstract: A method of joining a ball member to an end of a cylindrical matrix plunger body by resistance welding thereby to make a plunger for use in a directional control valve for controlling fluid communication in said valve is disclosed. A resistance welder for the method has a pair of electrodes. The ball member is placed in contact with a conical recess within the matrix plunger body and with a conforming surface of one of said electrodes so as to form a circular first contact between the ball member and the matrix plunger body and a spherical second contact between the ball member and the one electrode such that electrical contact resistance at the first contact is greater than that at the second contact. Then, an electric current at a constant rate flows for a controlled period of time through the first and second contacts with the ball member which is kept in contact with the matrix plunger body under pressure by the electrode.