Abstract: The present invention provides a nitride semiconductor device comprising an active layer of a quantum well structure, a first conductive clad layer and a second conductive clad layer. The first conductive clad layer is made of the quaternary nitride semiconductor InAlGaN having a lattice constant equal to or larger than that of the active layer and includes a first nitride semiconductor layer having an energy band gap larger than that of the active layer, a second nitride semiconductor layer having an energy band gap smaller than that of the first nitride semiconductor layer and a third nitride semiconductor layer having an energy band gap larger than that of the second nitride semiconductor layer, sequentially closer to the active layer.

Abstract: This invention provides a complementary color polarizer using a single polarizing film followed by a stack of two or more retarders. In a preferred embodiment, the color polarizers of this invention produce orthogonally polarized complementary primary colors (red/cyan, green/magenta, or blue/yellow). This invention further provides color filters which utilize the color polarizers of this invention in combination with a polarization separator to separate the orthogonally polarized colors. The polarization separator can be passive, such as a polarizing beam splitter, or active, such as a switchable polarizer. The switchable polarizer can employ a nematic or a smectic liquid crystal cell. Two color filters of this invention can be cascaded to provide a three color (RGB) filter with an off-state. In combination with a monochrome display or camera, the color filters of this invention provide color displays or cameras.

Abstract: The present invention discloses a method of operating an active matrix liquid crystal display device having a liquid crystal layer between a pair of substrates and at least one active device to each of picture element electrodes on at least one of the substrates, so that a driving signal applied to a picture element electrode during one frame cycle is always on a side of a voltage having an identical polarity, which is substantially free from scattering in the display, can be operated at a low driving voltage and obtain high contrast.

Abstract: A cover for an indicator panel of an electronic apparatus which is mounted on a recess formed on the indicator panel and pivotably movable so as to cover the indicator panel in a closed state, including a frame means which has first and second openings, a pair of hinges extending outwardly from both sides thereof and a tapered portion extending outwardly from the hinge-forming side of a lower side wall thereof, a pair of touch-sensitive panels made of a transparent material which are fitted into the first and second openings, a pair of display panels made of a transparent material mounted on the first and second openings which have touch patterns printed thereon with a transparent medium, an outer panel made of translucent acrylic resin which is disposed spaced at a given distance from the display panels, and a plurality of light sources provided in the frame means, wherein the touch patterns are reflected or projected on the touch-sensitive panels by light emitted from the light sources.