Abstract: There is provided a hydrodynamic bearing device that maintains high bearing angular stiffness, and that prevents oil film separation in the bearing by smoothly discharging any bubbles present inside the bearing. With a hydrodynamic bearing device, a communicating hole and a radial hydrodynamic groove constitute a circulation path for a lubricant, and a first thrust bearing surface is provided at a location in contact with the circulation path. A first hydrodynamic groove formed in the first thrust bearing surface is a spiral groove with a pump-in pattern. Any bubbles in the bearing are smoothly discharged by the circulation of the lubricant produced by the asymmetrical radial hydrodynamic groove. The pressure generated at the thrust bearing surface during rotation of the bearing has a distribution such that there is a wide range of high pressure.

Abstract: In a hydrodynamic bearing device in which a radial bearing face having a dynamic pressure generating groove on a shaft or an inner periphery of a sleeve is provided and a clearance between the shaft and the sleeve is filled with lubricant, an annular depression is provided on one end face of the sleeve adjacent to a rotor hub and a cover plate for covering the depression is attached to the sleeve so as to define a reservoir for the lubricant or air for the purpose of preventing such a risk that absence of an oil film occurs in clearances of a bearing of the hydrodynamic bearing device due to outflow of oil upon forcing of the oil by air received into the bearing. A step portion is provided on the other end face of the sleeve such that the step portion and the reservoir are communicated with each other by a communication hole. During operation of the hydrodynamic bearing device, air in the hydrodynamic bearing device reaches the reservoir via the communication hole so as to be discharged from the reservoir.

Abstract: The angular stiffness of a bearing is kept high, and at the same time air inside the bearing is discharged smoothly, without accumulating, which prevents oil film separation on the bearing. With the present invention, a communicating hole is provided, the hole and a radial hydrodynamic groove constitute a circulation path for a lubricant, there is a first thrust bearing face in contact with the circulation path, there is a first hydrodynamic groove on the face, this groove is a herringbone groove with a pump-in pattern, and no low-pressure part is generated in the thrust bearing, so even if the bearing undergoes a pressure change, there is no risk that the air accumulated in a low-pressure part will expand and cause oil film separation on the bearing face.

Abstract: A capacity layer is formed of non-doped polysilicon. Unlike capacity layers formed of an oxide film, generation of seams and the like can be suppressed and thereby a stable capacity layer can be formed. Moreover, polysilicon used as a capacity layer may be doped polysilicon, and an oxide film formed on the surface of the polysilicon also serves as a capacity film. Thus, provision of an insulated gate device featuring low capacity is made possible.

Abstract: In a conventional semiconductor device, there was a problem that, in a guard ring region, a shape of a depletion layer is distorted and stable withstand voltage characteristics cannot be obtained. In a semiconductor device of the present invention, a thermal oxide film in an actual operation region and a thermal oxide film in a guard ring region are formed in the same process. Thereafter, the thermal oxide film is once removed and is formed again. Thus, a film thickness of the thermal oxide film on the upper surface of the guard ring region is set to, for example, about 8000 to 10000 ?. Accordingly, a CVD oxide film including moving ions is formed in a position distant from a surface of an epitaxial layer. Consequently, distortion of a depletion layer, which is influenced by the moving ions, is suppressed and desired withstand voltage characteristics can be maintained.

Abstract: To prevent air from being trapped inside a bearing and causing the bearing to have oil film rupture and NPPR to deteriorate. A flange having a shape substantially like a disc is provided integrally with a shaft near its lower portion. A sleeve having a bearing hole is fitted to the shaft so as to be relatively rotatable. Hydrodynamic grooves are provided on at least one of an outer periphery of the shaft and an inner periphery of the sleeve. The flange forms a thrust bearing surface with a lower end surface of the sleeve. Hydrodynamic grooves are provided on at least one of the lower surface of the sleeve and an upper surface of the flange. During rotation of the bearing, the hydrodynamic grooves circulate the lubricant. Capillary pressures at respective portions in the lubricant circulation path have difference in magnitudes.

Abstract: In order to prevent oil leakage in a hydrodynamic bearing device comprising an opening section in close proximity to a radial bearing and a lubricating fluid reservoir, a shaft 10, thrust flange 16, sleeve 11, seal plate 21, and stopper plate 20 are provided, a radial dynamic pressure bearing is formed in a radial clearance between the shaft 10 and sleeve 11, and a thrust dynamic pressure bearing is formed in a thrust direction clearance between the sleeve 11 and thrust flange 16. A connecting hole 11d is formed that connects a gap between the sleeve 11 and seal plate 21 and a thrust direction gap between the sleeve 11 and thrust flange 16. The relationship A<B<C is satisfied, where A is a radial clearance, B is a clearance between an outer peripheral surface of the shaft 10 and an inner peripheral surface of the seal plate 21, and C is a clearance between a lower surface of the seal plate 21 and an upper end face of the sleeve 11.

Abstract: A hydrodynamic bearing for a hard disk drive device is disclosed. An oil is filled in a clearance between an inner surface of the hub and an outer surface of the shaft, whereby a hydrodynamic radial bearing is formed between the inner periphery of the hub and the outer periphery of the shaft, and a hydrodynamic thrust bearing is formed between the top face of the shaft and the thrust plate. Between an outer peripheral part at the base end of the shaft and an inner peripheral part at the open end of the hub is formed a seal part in which a larger clearance is formed between the shaft and the hub than a clearance in the hydrodynamic radial bearing and in which the oil surface is positioned. An oil surface adjusting hole and a plug for sealing the hole are provided in the case opposite the seal part.

Abstract: PROBLEM: To prevent oil film breakage in bearings without expelling of air internally accumulated at the bearing. METHOD FOR SOLVING THE PROBLEM: A hydrodynamic bearing type rotary device in which radial hydrodynamic grooves and thrust hydrodynamic grooves form communicating channels; have communicating holes designed to communicate the groove end of the radial hydrodynamic groove on the side opposite the thrust hydrodynamic grooves with the groove end of the thrust hydrodynamic groove on the side opposite the radial hydrodynamic grooves; have a circulation route composed by the communicating hole, the radial hydrodynamic groove, and the thrust hydrodynamic groove; and circulate lubricating oil by means of a pump force of the hydrodynamic groove.

Abstract: The present invention relates to a dermatologic preparation containing a diamide derivative represented by the following formula (1): (wherein, R1 represents a linear or branched hydrocarbon group having 1 to 22 carbon atoms which may be substituted by one or more hydroxy and/or alkoxy groups, R2 represents a linear or branched divalent hydrocarbon group having 1 to 12 carbon atoms, and R3 represents a linear or branched divalent hydrocarbon group having 1 to 42 carbon atoms). This diamide derivative (1) is capable of fundamentally improving the water retention capacity and barrier functions of the horny layer, is excellent in miscibility and mixing stability and can be prepared efficiently at a low cost.

Abstract: In a hydrodynamic bearing type rotary device, relationships between the number of times of intermittence life, a bearing load, lubricating fluid viscosity, a bearing size, and the like are considered in order to provide a hydrodynamic bearing type rotary device which can secure appropriate intermittence life. In a hydrodynamic bearing type rotary device 15, a shaft is inserted into a bearing hole 1C of a sleeve 1 so as to be relatively rotatable. A value of a function (Nd) represented by the following relational expression (1) is set to be 100,000 or higher: Nd=?/(S·Ff·P·D)??(1) S: Material wear rate S=74800 (constant) ?: Absolute viscosity at 70° C. [N·S/mˆ2] (when the lubricating fluid is a liquid) I: Viscosity corresponding constant I=0.

Abstract: To prevent air from being trapped inside a bearing and causing the bearing to have oil film rupture and NRRO to deteriorate. In a hydrodynamic bearing, a first lubricant reservoir is provided in a gap between a lower surface of a hub and a sleeve, and a second lubricant reservoir is provided in a gap between an outer peripheral surface of the sleeve and an inner peripheral surface of the hub or an inner peripheral surface of a stopper member fixed to the hub. If air enters inside such a hydrodynamic bearing, the air has to be discharged. For this purpose, the relationship in widths of the radial bearing gap, the maximum gap of the first lubricant reservoir under the lower surface of the hub and the maximum gap of the second lubricant reservoir on the sleeve outer peripheral surface, or the relationship in magnitudes of capillary forces thereof is adjusted.

Abstract: A hydrodynamic bearing rotary device which can reduce rotation friction, and recording and reproducing apparatus including the same are 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.

Abstract: 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 plate 4 and the flange 3 is S1, a second gap between the flange 3 and a lower end surface of the sleeve 1 is S2, and a third gap between the upper end surface of the sleeve 1 and the hub 7 is S3, widths of the gaps satisfy the relational expression, S3>(S1+S2).

Abstract: In an embodiment of the present invention, after trenches, a gate oxide film and gate electrodes are formed, a channel layer is formed by plural high-acceleration ion implantations where acceleration voltages are different with one another. The channel layer is an impurity implanted layer on which diffusion by a heat treatment is not performed. The channel layer is allowed to have its impurity concentration substantially uniform in a depth-wise direction of the trenches, by implanting ions of the impurity at plural different times by use of a high-acceleration ion implantation system. Since a second region having almost no influence on a characteristic of the channel layer can be reduced, the channel layer having a minimum necessary depth can be obtained. The trenches are thus made shallow, and accordingly a capacitance can be reduced. Furthermore, an on resistance can be made lower by making an epitaxial layer thinner.

Abstract: 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.

Abstract: 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.

Abstract: A hydrodynamic bearing type rotary device which allows bubbles in a lubricating fluid to be surely discharged from a bearing portion is provided. A hydrodynamic bearing mechanism 40 of the hydrodynamic bearing type rotary device is formed of a sleeve 1, a shaft 2, a flange 3, a thrust plate 4, a seal cap 5, and oil 6. A first fluid reservoir F is formed between the sleeve 1, the flange 3, and the thrust plate 4. A second fluid reservoir H is formed between the sleeve 1 and the seal cap 5. In the sleeve 1, a communication hole G extending along an axial direction is formed. The first fluid reservoir F and the second fluid reservoir H communicate with each other through the communication hole G. The oil 6 is filled between the members. A capillary pressure is higher in the first fluid reservoir F than in the second fluid reservoir H.

Abstract: Radial dynamic pressure grooves are provided in a first region 4A and a second region 4B on the side of a fixed shaft 2. A vent 2D is provided inside the top end 2A of the fixed shaft 2. The vent 2D connects spaces over and under a flange 3 to each other. The flange 3 in an annular shape is fixed at the top end 2A of the fixed shaft 2. Thrust dynamic pressure grooves 3A and 3B are provided on the surfaces of the flange 3. A circulation hole 3C is provided in the flange 3, and connects spaces over and under the flange 3 to each other. A sleeve 4 revolves around the fixed shaft 2. A thrust plate 6 in an annular shape is fixed at the top of the sleeve 4 and opposed to the flange 3. The first region 4A, the second region 4B, the thrust dynamic pressure grooves 3A and 3B, and the circulation hole 3C of the flange 3 are filled with a lubricant 7.

Abstract: A hydrodynamic bearing type rotary device which can maintain an appropriate life by considering the relationship of the life of the bearing with radial load, eccentricity, an oil shearing work function, a rotation rate and the like is provided. A hydrodynamic bearing type rotary device 15 has an shaft being inserted into a bearing hole 1C of a sleeve 1 so as to be relatively rotatable, a hub rotor 7 being attached to one of the sleeve 1 or the shaft 2, which rotates, and a radial bearing surface having hydrodynamic grooves 3A and 3B formed on at least one of an outer peripheral surface of the shaft 2 and an inner peripheral surface of the sleeve 1.