Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Daisuke Itou

Takafumi Asada

Hiroaki Saito

Keigo Kusaka

Yasunori Yamamoto

Shinichiro Kataoka

Go Takata

Tsukasa Kawahara

Ryuji Ueda

Teruo Maruyama

Hiroyuki Kiriyama

Yasuhiro Asaida

Tomoharu Takeda

Short circuit failures and open circuit failures of light-emitting elements used for the backlight in an LCD panel can be reliably and easily detected. The voltage at the node between each series-connected light-emitting element array and a drive circuit is detected as a monitored voltage. A maximum detector detects the highest and a minimum detector detects the lowest of these monitored voltages. Short circuit or open circuit failure of a light-emitting element is detected by comparing the voltage difference between the maximum detector output and the minimum detector output with a specific reference voltage.

Light-emitting element driving device

The load driving apparatus according to the present invention includes a load current setting signal generating section, a load current generating section, a reference voltage generating section and a drive voltage generating section. The load current setting signal generating section generates a desired load current setting signal. The load current generating section generates a load current based on the load current setting signal to drive the load. The reference voltage generating section generates a reference voltage based on the load current setting signal. The drive voltage generating section generates a drive voltage, supplies the drive voltage to the load, generates a between-both-terminals voltage between both terminals of the load current generating section based on the drive voltage and controls the drive voltage so that the difference between the between-both-terminals voltage and the reference voltage becomes small.

Load driving apparatus

A hydrodynamic bearing rotary device which can reduce rotation friction, and recording and reproducing apparatus including the same is provided. In the hydrodynamic bearing rotary device, such as hard disc devices, a rotary shaft having a hub on one end is provided in a bearing of a sleeve so as to be rotatable. Thrust hydrodynamic grooves are provided on the other end surface of the rotary shaft, to form a thrust bearing with the thrust plate. A communication path is provided in the sleeve. The second gap between the hub and the sleeve end surface is used as a flow channel and is connected to the communication path. In this way, the rotation friction torque of the thrust bearing can be made sufficiently small, and internal pressure in bonded portions of the rotary shaft or the bottom plate can be suppressed. Thus, the oil can be prevented from oozing out from a small space of the bonded surfaces. Furthermore, the hydrodynamic bearing can be made thin. These effects can be combined to realize an optimal hydrodynamic bearing rotary device.

Hydrodynamic bearing rotary device and information apparatus

An object of the present invention is to provide a hydrodynamic bearing type rotary device which can improve rotation performance, suppress a friction torque, and reduce power consumption of motor, and a recording and reproducing apparatus including the same. A shaft having a flange on one end and a hub on the other end is provided with a bearing of a sleeve so as to be rotatable. The sleeve includes a communication hole. A third gap between the hub and the sleeve end surface is a flow path, and is connected to the communication hole. Provided that a first gap between a thrust plateand the flangeis S, a second gap between the flangeand a lower end surface of the sleeveis S, and a third gap between the upper end surface of the sleeveand the hubis S, widths of the gaps satisfy the relational expression, S(S+S).

Hydrodynamic bearing rotary device

A high-accuracy, long-life hydrodynamic bearing that does not cause oil film breakage in bearing clearances and a disc rotation apparatus using the bearing is disclosed. Oil film breakage is avoided as negative pressure is prevented from generating between the shaft and sleeve of the hydrodynamic bearing. Herringbone shaped dynamic pressure generating grooves, located on the thrust bearing section and the radial bearing section of the hydrodynamic bearing, are oil filled and have optimum shapes. The optimum shapes prevent the generation negative pressure and thus prevents the coagulation of air bubbles that can cause oil film breakage. The disc rotation apparatus, that holds a reproduction/recording disc, is concentrically secured to the hydrodynamic bearing and rotated. The disc is put into contact with magnetic or optical heads while rotating in the disc rotation apparatus. Both the hydrodynamic bearing and the disc rotation apparatus experience high reliability.

Hydrodynamic bearing and disc rotation apparatus using the same

Radial dynamic pressure grooves are provided in a first regionA and a second regionB on the side of a fixed shaft. A ventD is provided inside the top endA of the fixed shaft. The ventD connects spaces over and under a flangeto each other. The flangein an annular shape is fixed at the top endA of the fixed shaft. Thrust dynamic pressure groovesA andB are provided on the surfaces of the flange. A circulation holeC is provided in the flange, and connects spaces over and under the flangeto each other. A sleeverevolves around the fixed shaft. A thrust platein an annular shape is fixed at the top of the sleeveand opposed to the flange. The first regionA, the second regionB, the thrust dynamic pressure groovesA andB, and the circulation holeC of the flangeare filled with a lubricant. At the revolution of the sleeve, the lubricantis concentrated in each central part of the first regionA, the second regionB, and the thrust dynamic pressure groovesA andB and their vicinities, then raising the pressure. The sleevekeeps its stable high-speed revolution, avoiding contact with the fixed shaft. The lubricantcirculates on surfaces of the flangethrough the circulation holeC.

Hydrodynamic bearing and disk recording/reproducing apparatus having a vent inside a fixed shaft

A sleeveis fixed on a base. Radial dynamic-pressure generating groovesA andB are provided on an inner surface of the sleeve. A thrust platehermetically seals a lower opening end of the sleeve. A shaftis inserted inside the sleeve, being allowed to revolve. A flangeis fixed at the bottom end of the shaft, and its lower surface is placed close to an upper surface of the thrust plate. Thrust dynamic-pressure generating groovesA andB are provided on the surfaces of the flange. Gaps A&#x2013;H among the sleeve, the shaft, the flange, and the thrust plateare filled with a lubricant. HollowsC&#x2013;F are provided on the inner surface of the sleeve. The gaps A and C over the thrust dynamic-pressure generating groovesA andB and their vicinities are narrower than the surrounding gaps B and D (A&#x3c;B, A&#x3c;D, C&#x3c;B, and C&#x3c;D), and the surrounding gaps B and D are narrower than the gap H in the upper opening end of the sleeveand its vicinity (B&#x3c;H and D&#x3c;H). The gaps E and G over the radial dynamic-pressure generating grooves and their vicinities are narrower than the surrounding gaps D and F (E&#x3c;D, E&#x3c;F, G&#x3c;D, and G&#x3c;F), and the surrounding gaps D and F are narrower than the gap H in the upper opening end of the sleeveand its vicinity (D&#x3c;H and F&#x3c;H).

Hydrodynamic bearing and disk recording/reproducing apparatus

A fluid dynamic bearing device including a shaft having an interior pressure regulating hole by which a center portion of a thrust surface confronting a thrust plate and a lubricant pool portion of an inner circumferential surface of a sleeve are communicated with each other. Thus, the device is capable of obtaining stable thrust floating characteristics and preventing leaks of the lubricant as well as exhaustion of the lubricant.

Fluid dynamic bearing device and motor including the device

A vacuum pump includes a positive displacement vacuum pump structure section disposed on a discharge opening side; a kinetic vacuum pump structure section, disposed on a suction opening side, for providing a high vacuum; and a kinetic vacuum pump structure section, disposed on a suction opening side, for providing a high pumping speed. The construction of the kinetic vacuum pump structure section is different from that of the kinetic vacuum pump structure section so as to differ relative thereto in one of ultimate pressure, pumping speed, and pumping speed of sucked gas with respect to a molecular weight of the sucked gas.

Growing community of inventors

Osaka, Japan

Daisuke Itou