Abstract: An object detection device includes a wave transmitter to transmit a sound wave to an object, a wave receiver to receive the sound wave and generate a signal representing a reception result, and a controller to control transmission of the sound wave by the wave transmitter and obtain the receive signal from the wave receiver. The controller is configured or programmed to output a transmit signal to cause the wave transmitter to transmit the sound wave and obtain a corresponding receive signal. The controller is configured or programmed to generate detection information about the object by performing complexification on a correlation signal representing a correlation between the transmit signal and the receive signal. A signal corrector is configured or programmed to correct any of the correlation signal, the receive signal, and the transmit signal to mitigate a direct-current component in the correlation signal targeted for the complex analysis.

Abstract: A displacement detection device includes a transmitter, a receiver, and a controller configured or programmed to output a first transmission signal to the transmitter to transmit a modulated wave and acquire a responsive first reception signal in a first measurement period, extract first phase information indicating a phase defined in a correlation between a first transmission signal and a reception signal, output a second transmission signal to the transmitter and acquire a responsive second reception signal in a second measurement period after the first measurement period, extract second phase information indicating a phase defined in a correlation between the second transmission signal and reception signal, and detect a displacement of an object between the first and second measurement periods, depending on a difference between the first and second phase information.

Abstract: A GaN single crystal having a full width at half-maximum of the double-crystal X-ray rocking curve of 5-250 sec and a thickness of not less than 80 .mu.m, a method for producing the GaN single crystal having superior quality and sufficient thickness permitting its use as a substrate and a semiconductor light emitting element having high luminance and high reliability, comprising, as a substrate, the GaN single crystal having superior quality and/or sufficient thickness permitting its use as a substrate.

Abstract: A group-III nitride based light emitter such as LED and LD, which has a double heterostructure and which comprises a diffusion suppressive layer between a p-type cladding layer and an active layer. The diode having a diffusion suppressive layer of the present invention has higher luminous intensity, greater forward voltage, and longer lifetime than the conventional diodes.

Abstract: A GaN single crystal having a full width at half-maximum of the double-crystal X-ray rocking curve of 5-250 sec and a thickness of not less than 80 .mu.m, a method for producing the GaN single crystal having superior quality and sufficient thickness permitting its use as a substrate and a semiconductor light emitting element having high luminance and high reliability, comprising, as a substrate, the GaN single crystal having superior quality and/or sufficient thickness permitting its use as a substrate.

Abstract: A semiconductor light emitting element comprising a light emitting part comprising an AlGaInP active layer and a AlGaInP cladding layer, which is formed on a GaAs substrate, and an AlGaAs layer and a Ga.sub.x In.sub.1-x P layer (0.7.ltoreq.x.ltoreq.1.0) deposited in this order on said light emitting part, wherein said Ga.sub.x In.sub.1-x P layer has a thickness of not more than 1.0 .mu.m. According to the present invention, absorption of the emitted light by an electrode contact layer and the occurrence of an interfacial distortion between the electrode contact layer and the layer thereunder can be suppressed, and a semiconductor light emitting element permitting easy production thereof and having a high luminance and a long service life can be provided.

Abstract: A semiconductor light emitting element comprising a semiconductor substrate having a lower electrode on its back, a pn junction, a first light reflecting layer disposed between the substrate and the pn junction, an upper electrode, and a second light reflecting layer disposed between the pn junction and the upper electrode, the second light reflecting layer being capable of substantially reflecting the light heading toward the upper electrode, which preferably has, between the pn junction and the second light reflecting layer, a semiconductor layer having a wider bandgap than that of a light emitting layer formed by said pn junction. The semiconductor light emitting element of the invention is advantageous in that the light absorption in the upper electrode can be inhibited to permit efficient output of the light heading toward the upper electrode from the element, and luminance can be greatly increased by the effective output of the light from the element.

Abstract: An inorganic article used as a container for holding a solution for crystal growth according to the present invention is provided by filling the pores of substrate having a porous inorganic structure with an inorganic material which has a melting point of 400.degree. to 900.degree. C. A liquid-phase epitaxy apparatus according to the present invention is comprised of a crucible made of the inorganic article or from a material selected from P-BN, quartz and sapphire and has an arrangement with less sliding contact. Thus, the dispersion of diffusive elements contained in a solution during the epitaxial growth is prevented. Accordingly, both the article and the apparatus of the present invention permit growth of crystals having high quality and less structural defects, thus contributing to the production of a semiconductor device made of materials having high vapor pressure.