Abstract: According to one embodiment, an emitter comprise a base portion including an electron emission surface from which electrons are emitted, a pair of leg portions applying a voltage to the electron emission surface, and a rib portion formed by bending an edge of the base portion to a side opposite to the electron emission surface, on at least a part of an outline of the electron emission surface.

Abstract: According to one embodiment, a rotating anode X-ray tube includes a fixed shaft, a rotor, a lubricant, target, and a supporting member. The fixed shaft includes a small-diameter portion provided with a first radial bearing surface including first grooved surfaces, and a large-diameter portion provided with a second radial bearing surface including second grooved surfaces. The rotor includes a third radial bearing surface. The lubricant is filled in a gap between the fixed shaft and the rotor, and drawn by the first and second grooved surfaces.

Abstract: According to one embodiment, an emitter comprise a base portion including an electron emission surface from which electrons are emitted, a pair of leg portions applying a voltage to the electron emission surface, and a rib portion formed by bending an edge of the base portion to a side opposite to the electron emission surface, on at least a part of an outline of the electron emission surface.

Abstract: According to one embodiment, an X-ray tube includes an elongated anode target, a cathode, and a vacuum envelope. The cathode includes an electron emission source and a converging electrode including a trench portion. The trench portion includes a closest inner circumferential wall, an upper inner circumferential wall, and a lower inner circumferential wall. The electron emission source projects towards a opening of the trench portion from a boundary between the closest inner circumferential wall and the upper inner circumferential wall.

Abstract: According to one embodiment, an X-ray tube includes an elongated anode target, a cathode, and a vacuum envelope. The cathode includes an electron emission source and a converging electrode including a trench portion. The trench portion includes a closest inner circumferential wall, an upper inner circumferential wall, and a lower inner circumferential wall. The electron emission source projects towards a opening of the trench portion from a boundary between the closest inner circumferential wall and the upper inner circumferential wall.

Abstract: According to one embodiment, a rotating anode X-ray tube includes a fixed shaft, a rotor, a lubricant, target, and a supporting member. The fixed shaft includes a small-diameter portion provided with a first radial bearing surface including first grooved surfaces, and a large-diameter portion provided with a second radial bearing surface including second grooved surfaces. The rotor includes a third radial bearing surface. The lubricant is filled in a gap between the fixed shaft and the rotor, and drawn by the first and second grooved surfaces.

Abstract: An anterior wall of a case has a central aperture and two discharge apertures extending from the central aperture. There is an anterior chamber inside the anterior wall. Moisture such as rain water, even if entering the anterior chamber, is smoothly discharged out of the case from the discharge apertures along an inner face of the anterior chamber. As a result, it becomes possible to prevent the moisture from remaining and attaching to a first diaphragm in the anterior chamber and to prevent degradation of sound pressure collected by the first diaphragm through the central aperture and the discharge apertures.

Abstract: An anterior wall of a case has a central aperture and two discharge apertures extending from the central aperture. There is an anterior chamber inside the anterior wall. Moisture such as rain water, even if entering the anterior chamber, is smoothly discharged out of the case from the discharge apertures along an inner face of the anterior chamber. As a result, it becomes possible to prevent the moisture from remaining and attaching to a first diaphragm in the anterior chamber and to prevent degradation of sound pressure collected by the first diaphragm through the central aperture and the discharge apertures.

Abstract: A small and high-performance waterproof speaker which can be manufactured inexpensively by decreasing the number of components. Front face of a case (1) is sealed hermetically by a water resistant diaphragm (2) from which a voice coil (3) is projecting inward and a magnetic circuit part (5) having a part (6a) being fitted to the voice coil (3) and a permanent magnet (8) is secured to a first resilient plate (4) provided in the case (1). The first resilient plate (4) is provided with a plurality of through holes (18) and the fitting part (6a) is coupled with the diaphragm (2) through a first coupling member (13) of resilient material. On the other hand, an inertial member (12) is secured to a second resilient plate (11) disposed, oppositely to the first resilient plate (4), in the case (1) and the second resilient plate (11) is coupled with the first resilient plate (4) through a second coupling member (14) of resilient material.

Abstract: A small and high-performance waterproof speaker which can be manufactured inexpensively by decreasing the number of components. Front face of a case (1) is sealed hermetically by a water resistant diaphragm (2) from which a voice coil (3) is projecting inward and a magnetic circuit part (5) having a part (6a) being fitted to the voice coil (3) and a permanent magnet (8) is secured to a first resilient plate (4) provided in the case (1). The first resilient plate (4) is provided with a plurality of through holes (18) and the fitting part (6a) is coupled with the diaphragm (2) through a first coupling member (13) of resilient material. On the other hand, an inertial member (12) is secured to a second resilient plate (11) disposed, oppositely to the first resilient plate (4), in the case (1) and the second resilient plate (11) is coupled with the first resilient plate (4) through a second coupling member (14) of resilient material.

Abstract: An underwater communication apparatus is provided which enables safe and clear speech transmission. An exhalation pipe which defines an acoustic space for communicating with an interior space of a mouthpiece is connected at one end to a site adjacent a breathing port of the mouthpiece. An exhaust valve which allows the flow of air only from the mouthpiece toward an exhaust port of the exhalation pipe is provided adjacent the exhaust port. A sound receiver portion having a capacitor microphone is provided within the exhalation pipe at a site upstream of the exhaust valve. When voice is uttered while the mouthpiece is held in the mouth, exhaled air is emitted from the exhaust port through the exhalation pipe and the exhaust valve, so that the capacitor microphone is less liable to noise trouble due to bubbles produced at the exhaust port, or on the downstream side. Speech transmission is made underwater by a waterproof speaker on the basis of an output of the capacitor microphone.

Abstract: A power supply device has a primary coil, a detection coil and a controller. The detection coil detects and outputs as a change in induction voltage any load fluctuation resulting from change in distance between the primary coil and a secondary coil. The controller controls, based on the change in the induction voltage output by the detection coil, an output of an oscillation circuit to hold power supplied to the secondary coil to a constant level. Therefore, even if the distance between the primary coil and the secondary coil changes, power supplied to battery connected to the secondary coil is stable. In particular, when the distance between the primary coil and the secondary coil becomes far, the controller increases the output of the oscillation circuit.