Abstract: The present invention is directed to an opening structure of a fuel tank having a fuel tank wall made of a plurality of plastic layers with an opening portion formed to be integral with the fuel tank wall. The opening structure includes a cylindrical portion extended from the opening portion outward of the fuel tank wall, an overlapping portion extended from an end of the cylindrical portion to enlarge the diameter of the opening portion and bent at a bent portion to form an outer surface parallel with an opening end surface of the opening portion, and a compressed portion with at least a portion of the overlapping portion compressed in a direction perpendicular to the opening end surface of the opening portion. The opening structure may further include an annular member which is disposed around the opening portion to be in contact with the overlapping portion and the cylindrical portion.

Abstract: A liquid crystal display comprises an input for inputting a video signal from a host and a storage medium for storing the previous brightness level of the video signal input through the input. A determinator is provided for determining an output brightness level based on the previous brightness level stored in the storage medium and the next brightness level of the next video signal input to the input, so as to make the time integration quantity of a brightness change substantially equal to an ideal quantity of light in a stationary state with respect to the next brightness level. Further included are drivers for driving an image displaying liquid crystal cell based on the output brightness level determined by the determinator.

Abstract: A semiconductor light emitting diode (10) is formed on an n-type GaAs substrate and includes: an AlGaInP based double heterojunction structure in which an active layer (16) is sandwiched between cladding layers (14, 18); an upper P-type contact layer 20; and a ring-shaped upper electrode (22) having an opening (28), wherein light is emitted through the upper p-type contact layer (20) and the opening (28) of the upper electrode (22). The upper p-type contact layer (20) is a semiconductor layer made of AlGaAs or AlGaAsP having an Al content of 0.5 or more, and doped with impurities at a carrier concentration of 5×1018 cm−3 or more. The semiconductor light emitting diode emits light in a desired emission pattern and at higher intensities, and is capable of being fabricated by relatively simple processes.

Abstract: A semiconductor laser has a laser active layer for receiving current from a pair of electrode for lasing operation. The end region in the vicinity of both the facets of the active layer does not receive current from the electrode. The interfaces between the end portions and the central portion receiving current are slanted from the plane normal to the optical axis of the laser, for stable mode operation of the laser device.

Abstract: This single voltage controlled oscillator for a PLL circuit has two control loops: a low noise ration is maintained by a main loop; while a wide frequency capture range is ensured by a sub-loop controlled by a one-chip microcomputer. The main control loop is a low gain loop with a narrow capture range that compares the phase of the output of the PLL circuit with the phase of a horizontal synchronous video signal supplied to a LCD display. The sub-loop is a high gain loop with a broad frequency range that includes a processor that monitors the lock on the main loop. When the lock is broken, the processor increments or decrements the voltage supplied to this sub-loop in one or more steps until the lock is reestablished, and the PLL circuit is again operating within the narrow capture range of the low gain loop.

Abstract: A semiconductor laser is produced by forming a laser activation section and a light emitting section having an InGaAsP layer as a quantum well on a GaAs substrate according to metal organic chemical vapor deposition by using a selective area growth mask, in such a manner that the laser activation section and the light emitting section have different film thicknesses. The laser activation section includes a laser activation layer whose oscillation wavelength is set to 0.8 to 1.1 .mu.m, and the light emitting section includes an optical waveguide layer having a broader forbidden band than the laser activation layer.

Abstract: An optical switch comprises a substrate, a lower cladding layer, a waveguide layer, and an upper cladding layer each formed of a semiconductor, and in which at least one of the three layers except the substrate has a quantum well structure at a quantum confined potential. The well plane of the quantum well structure is symmetrical with respect to the center position thereof, and varies in proportion to the square of the distance from the center position. If an electric field is applied perpendicular to the well plane, the respective changes in the absorption coefficient and refractive index in the vicinity of the absorption edge are influenced by absorption peak shifts attributable to both 1e-1hh and 1e-11h transitions. Thus, the optical switch operates in response to both TE and TM mode light without depending on polarization.