The present invention relates to a high intensity blending apparatus, particularly for blending operations designed to cause additive materials to become affixed to the surface of base particles. The tool comprises a shank having riser members at each end, such risers being angled to the axis of the shank between 10 and 16 degrees and having regions toward the trailing edges that are thicker than regions near the leading edges.

The field of the present invention relates to high intensity blending apparatus, particularly for blending operations designed to cause additive materials to become affixed to the surface of base particles. More particularly, the proposed invention relates to an improved blending tool for producing surface modifications to electrophotographic and related toner particles.
State of the art electrophotographic imaging systems increasingly call for toner particles having narrow distributions of sizes in ranges less than 10 microns. Along with such narrow distributions and small sizes, such toners require increased surface additive coverage since increased quantities of surface additives improve charge control properties, decrease adhesion between toner particles, and decrease Hybrid Scavangeless Development ("HSD") developer wire contamination in electrophotographic systems. The blending tool embodiments of the present invention enable a toner having a high degree of coverage by surface additives and having a high degree of adhesion of the surface additives to the toner particles. The present invention also relates to an improved method for producing surface modifications to electrophotographic and related toner particles. This method comprises using an improved blending tool to cause increased blending intensity during high speed blending processes.
A typical process for manufacture of electrophotographic, electrostatic or similar toners is demonstrated by the following description of a typical toner manufacturing process. For conventional toners, the process generally begins by melt-mixing the heated polymer resin with a colorant in an extruder, such as a Werner Pfleiderer ZSK-53 or WP-28 extruder, whereby the pigment is dispersed in the polymer. For example, the Werner Pfleiderer WP-28 extruder when equipped with a 15 horsepower motor is well-suited for melt-blending the resin, colorant, and additives. This extruder has a 28 mm barrel diameter and is considered semiworks-scale, running at peak throughputs of about 3 to 12 lbs./hour.
Toner colorants are particulate pigments or, alternatively, are dyes. Numerous colorants can be used in this process. A suitable toner resin is then mixed with the colorant by the downstream injection of the colorant dispersion. Examples of suitable toner resins which can be used include but are not limited to polyamides, epoxies, diolefins, polyesters, polyurethanes, vinyl resins and polymeric esterification products of a dicarboxylic acid and a diol comprising a diphenol.
Illustrative examples of suitable toner resins selected for the toner and developer compositions of the present invention include vinyl polymers such as styrene polymers, acrylonitrile polymers, vinyl ether polymers, acrylate and methacrylate polymers; epoxy polymers; diolefins; polyurethanes; polyamides and polyimides; polyesters such as the polymeric esterification products of a dicarboxylic acid and a diol comprising a diphenol, crosslinked polyesters; and the like. The polymer resins selected for the toner compositions of the present invention include homopolymers or copolymers of two or more monomers. Furthermore, the above-mentioned polymer resins may also be crosslinked.
Illustrative vinyl monomer units in the vinyl polymers include styrene, substituted styrenes such as methyl styrene, chlorostyrene, styrene acrylates and styrene methacrylates; vinyl esters like the esters of monocarboxylic acids including methyl acrylate, ethyl acrylate, n-butyl-acrylate, isobutyl acrylate, propyl acrylate, pentyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methylalphachloracrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, propyl methacrylate, and pentyl methacrylate; styrene butadienes; vinyl chloride; acrylonitrile; acrylamide; alkyl vinyl ether and the like. Further examples include p-chlorostyrene vinyl naphthalene, unsaturated mono-olefins such as ethylene, propylene, butylene and isobutylene; vinyl halides such as vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl butyrate; acrylonitrile, methacrylonitrile, acrylamide, vinyl ethers, inclusive of vinyl methyl ether, vinyl isobutyl ether, and vinyl ethyl ether; vinyl ketones inclusive of vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; vinylidene halides such as vinylidene chloride and vinylidene chlorofluoride; N-vinyl indole, N-vinyl pyrrolidone; and the like.
Illustrative examples of the dicarboxylic acid units in the polyester resins suitable for use in the toner compositions of the present invention include phthalic acid, terephthalic acid, isophthalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, dimethyl glutaric acid, bromoadipic acids, dichloroglutaric acids, and the like; while illustrative examples of the diol units in the polyester resins include ethanediol, propanediols, butanediols, pentanediols, pinacol, cyclopentanediols, hydrobenzoin, bis(hydroxyphenyl)alkanes, dihydroxybiphenyl, substituted dihydroxybiphenyls, and the like. Resin binders for use in the present invention comprise polyester resins containing both linear portions and cross-linked portions of the type described in U.S. Pat. No. 5,227,460 (incorporated herein by reference above).
The resin or resins are generally present in the resin-toner mixture in an amount of from about 50 percent to about 100 percent by weight of the toner composition, and preferably from about 80 percent to about 100 percent by weight.
Additional "internal" components of the toner may be added to the resin prior to mixing the toner with the additive. Alternatively, these components may be added during extrusion. Various known suitable effective charge control additives can be incorporated into toner compositions, such as quaternary ammonium compounds and alkyl pyridinium compounds, including cetyl pyridinium halides and cetyl pyridinium tetrafluoroborates, as disclosed in U.S. Pat. No. 4,298,672, the disclosure of which is totally incorporated herein by reference, distearyl dimethyl ammonium methyl sulfate, and the like. The internal charge enhancing additives are usually present in the final toner composition in an amount of from about 0 percent by weight to about 20 percent by weight.
After the resin, colorants, and internal additives have been extruded, the resin mixture is reduced in size by any suitable method including those known in the art. Such reduction is aided by the brittleness of most toners that causes the resin to fracture when impacted. This allows rapid particle size reduction in pulverizers or attritors such as media mills, jet mills, hammer mills, or similar devices. An example of a suitable jet mill is an Alpine 800 AFG Fluidized Bed Opposed Jet Mill. Such a jet mill is capable of reducing typical toner particles to a size of about 4 microns to about 30 microns. For color toners, toner particle sizes may average within an even smaller range of 4–10 microns.
Inside the jet mill, a classification process sorts the particles according to size. Particles classified as too large are rejected by a classifier wheel and conveyed by air to the grinding zone inside the jet mill for further reduction. Particles within the accepted range are passed onto the next toner manufacturing process.
After reduction of particle size by grinding or pulverizing, a classification process sorts the particles according to size. Particles classified as too fine are removed from the product eligible particles. The fine particles have a significant impact on print quality and the concentration of these particles varies between products. The product eligible particles are collected separately and passed to the next toner manufacturing process.
After classification, the next typical process is a high speed blending process wherein surface additive particles are mixed with the classified toner particles within a high speed blender. These additives include but are not limited to stabilizers, waxes, flow agents, other toners and charge control additives. Specific additives suitable for use in toners include fumed silica, silicon derivatives, ferric oxide, hydroxy terminated polyethylenes, polyolefin waxes, including polyethylenes and polypropylenes, polymethylmethacrylate, zinc stearate, chromium oxide, aluminum oxide, titanium oxide, stearic acid, and polyvinylidene fluorides.
The amount of external additives is measured in terms of percentage by weight of the toner composition, and the additives themselves are not included when calculating the percentage composition of the toner. For example, a toner composition containing a resin, a colorant, and an external additive may comprise 80 percent by weight resin and 20 percent by weight colorant. The amount of external additive present is reported in terms of its percent by weight of the combined resin and colorant. The combination of smaller toner particle sizes required by some newer color toners and the increased size and coverage of additive particles for such color toners increases the need for high intensity blending.
The above additives are typically added to the pulverized toner particles in a high speed blender such as a Henschel Blender FM-10, 75 or 600 blender. The high intensity blending serves to break additive agglomerates into the appropriate nanometer size, evenly distribute the smallest possible additive particles within the toner batch, and attach the smaller additive particles to toner particles. Each of these processes occurs concurrently within the blender. Additive particles become attached to the surface of the pulverized toner particles during collisions between particles and between particles and the blending tool as it rotates. It is believed that such attachment between toner particles and surface additives occurs due to both mechanical impaction and electrostatic attractions. The amount of such attachments is proportional to the intensity level of blending which, in turn, is a function of both the speed and shape of the blending tool. The amount of time used for the blending process plus the intensity determines how much energy is applied during the blending process. For an efficient blending tool that avoids snow plowing and excessive vortices and low density regions, "intensity" can be effectively measured by reference to the power consumed by the blending motor per unit mass of blended toner (typically expressed as Watts/lb). Using a standard Henschel Blender tool to manufacture conventional toners, the blending times typically range from one (1) minute to twenty (20) minutes per typical batch of 1–500 kilograms. For certain more recent toners such as toners for Xerox Docucenter 265 and related multifunctional printers, blending speed and times are increased in order to assure that multiple layers of surface additives become attached to the toner particles. Additionally, for those toners that require a greater proportion of additive particles in excess of 25 nanometers, more blending speed and time is required to force the larger additives into the base resin particles.
The process of manufacturing toners is completed by a screening process to remove toner agglomerates and other large debris. Such screening operation may typically be performed using a Sweco Turbo screen set to 37 to 105 micron openings.
The above description of a process to manufacture an electrophotographic toner may be varied depending upon the requirements of particular toners. In particular, for full process color printing, colorants typically comprise yellow, cyan, magenta, and black colorants added to separate dispersions for each color toner. Colored toner typically comprises much smaller particle size than black toner, in the order of 4–10 microns. The smaller particle size makes the manufacturing of the toner more difficult with regard to material handling, classification and blending.
The above described process for making electrophotographic toners is well known in the art. More information concerning methods and apparatus for manufacture of toner are available in the following U.S. patents, each of the disclosures of which are incorporated herein: U.S. Pat. No. 4,338,380 issued to Erickson, et al; U.S. Pat. No. 4,298,672 issued to Chin; U.S. Pat. No. 3,944,493 issued to Jadwin; U.S. Pat. No. 4,007,293 issued to Mincer, et al; U.S. Pat. No. 4,054,465 issued to Ziobrowski; U.S. Pat. No. 4,079,014 issued to Burness, et al; U.S. Pat. No. 4,394,430 issued to Jadwin, et al; U.S. Pat. No. 4,433,040 issued to Niimura, et al; U.S. Pat. No. 4,845,003 issued to Kiriu, et al; U.S. Pat. No. 4,894,308 issued to Mahabadi et al.; U.S. Pat. No. 4,937,157 issued to Haack, et al; U.S. Pat. No. 4,937,439 issued to Chang et al.; U.S. Pat. No. 5,370,962 issued to Anderson, et al; U.S. Pat. No. 5,624,079 issued to Higuchi et al.; U.S. Pat. No. 5,716,751 issued to Bertrand et al.; U.S. Pat. No. 5,763,132 issued to Ott et al.; U.S. Pat. No. 5,874,034 issued to Proper et al.; and U.S. Pat. No. 5,998,079 issued to Tompson et al.
In addition to the above conventional process for manufacturing toners, other methods for making toners may also be used. In particular, emulsion/aggregation/coalescence processes (the "EA process") for the preparation of toners are illustrated in a number of Xerox Corporation patents, the disclosures of each of which are totally incorporated herein by reference, such as U.S. Pat. Nos. 5,290,654, 5,278,020, 5,308,734, 5,370,963, 5,344,738, 5,403,693, 5,418,108, 5,364,729, and 5,346,797; and also of interest may be U.S. Pat. Nos. 5,348,832; 5,405,728; 5,366,841; 5,496,676; 5,527,658; 5,585,215; 5,650,255; 5,650,256; 5,501,935; 5,723,253; 5,744,520; 5,763,133; 5,766,818; 5,747,215; 5,827,633; 5,853,944; 5,804,349; 5,840,462; 5,869,215; 5,863,698; 5,902,710; 5,910,387; 5,916,725; 5,919,595; 5,925,488, and 5,977,210. The appropriate components and processes of the above Xerox Corporation patents can be selected for the processes of the present invention in embodiments thereof. In both the above described conventional process and in processes such as the EA process, surface additive particles are added using high intensity blending processes.
High speed blending of dry, dispersed, or slurried particles is a common operation in the preparation of many industrial products. Examples of products commonly made using such high-speed blending operations include, without limitation, paint and colorant dispersions, pigments, varnishes, inks, pharmaceuticals, cosmetics, adhesives, food, food colorants, flavorings, beverages, rubber, and many plastic products. In some industrial operations, the impacts created during such high-speed blending are used both to uniformly mix the blend media and, additionally, to cause attachment of additive chemicals to the surface of particles (including resin molecules or conglomerates of resins and particles) in order to impart additional chemical, mechanical, and/or electrostatic properties. Such attachment between particles is typically caused by both mechanical impaction and electrostatic bonding between additives and particles as a result of the extreme pressures created by particle/additive impacts within the blender device. Among the products wherein attachments between particles and/or resins and additive particles are important during at least one stage of manufacture are paint dispersions, inks, pigments, rubber, and certain plastics.
High intensity blending typically occurs in a blending machine, and the blending intensity is greatly influenced by the shape and speed of the blending tool used in the blending process. A typical blending machine and blending tool of the prior art is exemplified in FIGS. 1 and 2. FIG. 1 is a schematic elevational view of a blending machine 2. Blending machine 2 comprises a vessel 10 into which materials to be mixed and blended are added before or during the blending process. Housing base 12 supports the weight of vessel 10 and its contents. Motor 13 is located within housing base 12 such that its drive shaft 14 extends vertically through an aperture in housing 12. Shaft 14 also extends into vessel 10 through sealed aperture 15 located at the bottom of vessel 10. Upon rotation, shaft 14 has an axis of rotation that generally is orthogonal to the bottom of vessel 10. Shaft 14 is fitted with a locking fixture 17 at its end, and blending tool 16 is rigidly attached to shaft 14 by locking fixture 17. Before blending is commenced, lid 18 is lowered and fastened onto vessel 10 to prevent spillage. For high intensity blending, the speed of the rotating tool at its outside edge generally exceeds 50 ft./second. The higher the speed, the more intense, and tool speeds in excess of 90 ft./second, or 120 ft./second are common.
Various shapes and thicknesses of blending tools are possible. Various configurations are shown in the brochures and catalogues offered by manufacturer's of high-speed blending equipment such as Henschel, Littleford Day Inc., and other vendors. The tool shown in FIG. 1 is based upon a tool for high intensity blending produced by Littleford Day, Inc. and is discussed in more detail in relation to FIG. 3 discussed below. Among the reasons for different configurations of blending tools are (i) different viscosities often require differently shaped tools to efficiently utilize the power and torque of the blending motor; and (ii) different blending applications require different intensities of blending. For instance, some food processing applications may require a very fine distribution of small solid particles such as colorants and flavorings within a liquid medium. As another example, the processing of snow cones requires rapid and very high intensity blending designed to shatter ice cubes into small particles which are then mixed within the blender with flavored syrups to form a slurry.
As discussed more fully below, the shape of blending tool 16 greatly affects the intensity of blending. One type of tool design attempts to achieve high intensity blending by enlarging collision surfaces, thereby increasing the number of collisions per unit of time, or intensity. One problem with this type of tool is that particles tend to become stuck to the front part of the tool, thereby decreasing efficiency and rendering some particles un-mixed. An example of an improved tool using an enlarged collision surface that attempts to overcome this "snow-plowing" effect is disclosed in U.S. Pat. No. 6,523,996 entitled "BLENDING TOOL WITH AN ENLARGED COLLISION SURFACE FOR INCREASED BLEND INTENSITY AND METHOD OF BLENDING TONERS," hereby incorporated by reference. Even when overcoming the "snow-plow" effect, a second limitation of prior art tools with enlarged collision surfaces is that particles in the blender tend to swirl in the direction and nearly at the speed of the moving tool. Thus, the impact speed between the tool and a statistical average of particles moving within vessel 10 is less than the speed of the tool itself since the particles generally are moving the same direction as the tool.
Another type of a blending tool that is more typically used for blending toners and additives is shown in FIG. 2 as tool 26. As shown, tool 26 comprises 3 wing shaped blades, each arranged orthoganally to the blade immediately above and/or below it. Tool 26 as shown has blades 27, 28, and 29. Blade 27, the bottom blade, is generally called "the scraper" and serves to lift particles from the bottom and provide initial motion to the particles. Blade 28, the middle blade, is called "the fluidizing tool" and serves to provide additional mechanical energy to the mixture. Blade 29, the top blade, is called the "horn tool" and is usually bent upward at an angle. The high speed distal tips proximal the wall of the blending vessel are primarily responsible for additive dispersion and inducing/providing impact/shear energy to attach the additive particles to the toner. Since tool 26 is designed such that each of its separate blades are relatively thin and therefore flow through the toner and additive mixture without accretion of particles on the leading edges, measure of the power consumed by the blending motor is a good indicator of the intensity of blending that occurs during use of the tool. This power consumption is measured as the specific power of a tool, defined as follows:
      Specific                          Power    =                              Load                                                              Power                -                  No                                                              Load                                                              Power                            Batch                                                  Weight                        [              Watt                          /                                  lb          .                    ]      The Specific Power of tool 26 is shown in FIG. 8 in relation to different speeds of rotation. The significance of the data shown in FIGS. 9 and 10 is discussed below when describing advantages of an embodiment of the present invention. It should be noted, however, that tool 26 also embodies the limitation described above wherein the actual collision energy between particles is usually less than the speed of the tool itself since each of blades 27, 28, an 29 have the effect of swirling particles within the blending vessel in the direction of tool rotation.
Some tools of the prior art are designed to achieve blend intensity through creation of vortices and shear forces. One such tool is sold by Littleford Day Inc. for use in its blenders and appears in cross-section as tool 16 in FIG. 1. As shown in perspective view in FIG. 3, the Littleford tool 16 has center shank 20 with a central bushing fixture 17A for engagement with locking fixture 17 at the end of shaft 14 (both fixture 17 and shaft 14 are shown in FIG. 1). Bushing fixture 17A includes a notch conforming to a male locking key feature on locking fixture 17 (from FIG. 1). Arrow 21 shows the direction in which tool 16 rotates upon shaft 14. A second scraper blade 16A may be mounted below tool 16 onto shaft 14 as shown in FIG. 3. In the configuration shown, the Littleford scraper blade 16A comprises a shank mounted orthogonally to center shank 20 that emerges from underneath shank 20 in an essentially horizontal manner and then dips downward near its end region. The end region of blade 16A is shaped into a flat club shape with a leading edge near the bottom of the blending vessel (not shown) and the trailing edge sloping slightly upward to impart lift to particles scraped from the bottom of the vessel. The leading edge of the club shape runs from an outside corner nearest the blending vessel wall inwardly towards the general direction of shaft 14. The scraper blades are shorter than shank 20, and the combination of this shorter length plus the shape of the leading edge indicates that the function of the Littleford scraper blade is to lift particles in the middle of the blending vessel upward from the bottom of the vessel.
In contrast to the tool shown in FIG. 2, tool 16 comprises vertical risers 19A and 19B that are fixed to the end of center shank 20 at its point of greatest velocity during rotation around central bushing 17A. These vertical risers 19A and 19B are angled, or canted, in relation to the axis of center shank 20 at an angle of 17 degrees. In this manner, the leading edges 21A and 21B of risers 19A and 19B are proximate the wall of blending vessel 10 (from FIG. 1) while the trailing edges 22A and 22B are further removed from vessel wall 10. Applicant believes that tool 16 operates by creating shear forces between particles caught in the space created between the outside surface of risers 19A and 19B and the wall of vessel 10. Since trailing edges 22B and 22A are further removed from the wall, a vortex is created in this space. It is believed that particles trapped in these vortices follow the tool at or nearly at the speed of leading edges 19A and 19B. In contrast, particles that have slipped through gap between leading edge 19A and 19B and the wall of vessel 10 remain nearly stationary. When particles swept along within the vortices behind leading edges 19A and 19B impact the nearly stationary particles along the vessel wall, then the speed of collision is at or nearly at the speed of the leading edges of the tool. Applicant has not found literature that describes the above effects. Instead, the above analysis results from Applicants' own investigation of blending tools.
An improvement upon the Littleford tool shown in FIGS. 1 and 3 is disclosed in U.S. Pat. No. 6,752,561, issued Jun. 22, 2004 to Kumar et al, which is hereby incorporated herein in its entirety. The tool of the '561 patent is shown in FIG. 4 and comprises a shank having a riser member at each end, such risers being angled to the axis of the shank between 10 and 16 degrees and having a height dimension greater that 20 percent of the diagonal dimension of the shank.
Although the tool shown in FIG. 4 has proven to achieve the specific power and blend intensity described in the '561, several problems have arisen. Specifically, experience has shown that the tool in FIG. 4 is prone to a static toner accumulation proximate to the rear of the inside edge of each riser. Toner that aggregates in such accumulation does not get blended adequately. A certain amount of such inadequately blended toner typically becomes loose during or after the blending operation, thereby resulting in a portion of a toner batch having inadequate additive coverage or adhesion. Without sufficient additive adhesion and coverage, the affected toner particles are likely to perform poorly during imaging operations. Accordingly, it would be very desirable to design a blending tool that creates substantially the same specific power and blending intensity as the tool described in the '561 patent but which incurs little or no static toner accumulation.
A second problem with the tool disclosed in the '561 patent is that the intense centrifugal forces imposed on the tool tends to bend the shank downward and, separately, the risers outward. Together, these deflections can cause structural failure of the tool. The bending is sufficient to permanently deform the risers outward from the intended vertical angle to the shank. Even without structural failure of the tool, such deflections can cause the tool to touch the blend chamber wall at high rotation speeds. The root cause of the deflections is the extreme bending moments of the tool at high rotation speeds that cause local stress levels to exceed the yield stress of the material. Although the tool can be reinforced with more material to inhibit deflection, such reinforcement increases tool mass, thereby decreasing blending efficiency while modestly increasing the amount of toner accumulation on the riser inside edge.
A third problem resulting from use of the tool of the '561 patent is that temperatures within the blending vessel may become undesirably high. When blending toners with the '561 tool, temperatures of 130 F are common. Such temperatures are uncomfortably close to the transition temperature of toner resins and, accordingly, risk melting and fusing of toner particles within the blending vessel.
As described above, the process of blending plays an increasingly important role in the manufacture of electrophotographic and similar toners. It would be advantageous if a blending tool design and blending method were found that achieves at least the same specific power and blending intensity as the tool of the '561 patent while minimizing static powder accumulation and outward deflection of the tool risers while maintaining temperatures within the blending vessel well below transition temperatures of typical toner resins.

High intensity blending tool with optimized risers for decreased toner agglomeration


An improved drive arrangement for a starter motor includes a rubber cushion between a drive plate and a pinion gear. The rubber cushion has seals at inner and outer locations which seal against the drive plate. In this way, the area between the drive plate and the rubber cushion is sealed to prevent contaminants from reaching the area and harming the connection between the drive plate and cushion.

This application relates to an improved seal for a connection between a driver plate and its associated rubber cushion in a starter motor drive assembly.
In the prior art, start motors are utilized to initiate turning a vehicle engine. An electric motor drives a pinion, which engages a ring gear. Upon rotation of the ring gear, the engine is turned to begin operation of the engine. At the same time, other components act to start the engine to be self-running.
In one known type of starter motor, the pinion gear is associated with the electric motor and is brought selectively into contact with the starter motor ring gear upon start-up of the electric motor. The electric motor has a drive shaft which rotates a drive plate spaced on an opposed side of the pinion from the side gear. A rubber cushion is positioned to connect the drive plate to the pinion. The drive plate is mounted on threads on the drive shaft. Upon start-up of the electric motor, the pinion is rotated. The pinion, rubber cushion and drive plate all move on the threads on the shaft such that the pinion engages the ring gear. Once the pinion engages the ring gear, the drive plate continues to move on the threads, and compresses the rubber cushion between the drive plate and the pinion. As the rubber cushion becomes compressed, the amount of torque transmitted from the shaft to the pinion increases due to the drive plate approaching the pinion, and the drive plate beginning to transmit a portion of the torque.
The above-described general operation for a starter motor is known in the art, and has achieved wide success. However, there are challenges with this design. The interface between the drive shaft and the drive plate, and in particular, the threaded connections, are greased. If there is too much grease placed at the interface, the grease will sometimes migrate into the area between the drive plate and the rubber cushion. This is undesirable, and can affect the connection between the drive plate and the rubber cushion. Moreover, the contaminants, such as water, oil, dust, etc., can move into the area between the drive plate and the rubber cushion. This is undesirable.


A method for manufacturing a magnetic disk substrate includes a step of polishing a glass-ceramic having a crystal phase consisting of crystal grains having an average diameter of less than 3 .mu.m with a polishing material having a grain diameter smaller than the diameter of the crystal grain. In one aspect of the invention, the glass-ceramic includes lithium disilicate (Li.sub.2 O--2SiO.sub.2) and alpha-quartz (alpha-SiO.sub.2) as predominant crystal phases and grown crystal grains of the alpha-quartz each have a globular grain structure consisting of aggregated particles and have a diameter within a range of 0.3 .mu.m-3.0 .mu.m.

This invention relates to a method for manufacturing a magnetic disk substrate made of glass-ceramic having an improved surface characteristic after polishing.
There is an increasing demand for a magnetic disk as an external storage medium of an office computer and a personal computer and various developments have been made for improving characteristics of a magnetic disk. A substrate for a magnetic disk is generally required to have the following characteristics:
(1) In the CSS (contact-start-stop) characteristic (hereinafter referred to as "CSS characteristic") of a magnetic disk, if the disk has a smooth surface having surface roughness (Ra) below 15.ANG., sticking between the head and the disk occurs due to increase in contact resistance caused by high rotation of the disk and, for this reason, the surface roughness (Ra) should be larger than 15.ANG.. Further, if the surface of the disk is a rough one having the surface roughness (Ra) exceeding 50.ANG., damage of the head or the disk tends to take place and, for this reason, the surface roughness (Ra) should not exceed 50.ANG..
(2) There is tendency to reducing glide height (i.e., interval between the head and surface of the disk) for improving recording density of the magnetic disk and, for this reason, the surface of the disk should be flat and smooth to such extent that a desired glide height can be achieved.
(3) The magnetic disk substrate should be free from crystal anisotropy and other defects and should have fine and uniform texture.
(4) The substrate should have mechanical strength and hardness which are sufficient for standing high speed rotation of the disk and contact with the head.
(5) The substrate should not include Na.sub.2 O ingredient in its material because if the substrate includes the Na.sub.2 O ingredient, a Na ion is diffused in the substrate during a film forming process with resulting deterioration in the characteristics of the substrate.
(6) The substrate should have chemical durability for resisting rinsing and etching with various chemicals.
An aluminum alloy has generally been used as a magnetic disk substrate in the past. The aluminum alloy however tends to develop undesirable projections or spot-like projections and depressions on the surface of the surface of the substrate during a polishing process due to various defects existing inherently in the material with resulting deficiency in its flatness and surface roughness. The aluminum alloy therefore cannot satisfy the current demand for high density recording required for coping with increase in the amount of information.
Known also in the art are various types of magnetic disk substrates made of a chemically reinforced glass which have been developed for eliminating the above described disadvantages of the magnetic disk substrate made of aluminum alloy. These magnetic disk substrates made of a chemically reinforced glass however have the following disadvantages:
(1) Since polishing of the substrate is made after the chemical reinforcing processing, the reinforced layer tends to become instable as the thickness of the magnetic disk is decreased.
(2) The substrate must be subjected to a mechanical or chemical texturing in order to improve the contact-start-stop characteristic and this requirement makes it difficult to manufacture magnetic disks in a large scale and at a low cost.
(3) Since the substrate includes Na.sub.2 O as an essential ingredient, the film forming characteristic is deteriorated and, as a result, a surface coating process becomes necessary. Further, for eliminating the requirement for the texturing for improving the contact-start-stop characteristic in the chemically reinforced glass or glass-ceramics, a process has recently been developed for making the surface of the substrate rough. This process however is also insufficient for producing magnetic disks in a large scale and at a low cost.
Some glass-ceramics are known as materials satisfying some of the above described requirements. For example, Japanese Patent Applcation Laid-open No. Sho 60-229234 discloses a SiO.sub.2 --Al.sub.2 O.sub.3 --Li.sub.2 O system glass-ceramic which includes alpha-quartz solid solution or beta-spodumene solid-solution as a main crystal phase and consists of crystal grains having a diameter of about 0.1-1.0 .mu.m. Japanese Patent Application Laid-open No. Sho 62-72547 discloses a SiO.sub.2 --Li.sub.2 O system glass-ceramic which includes, as main crystal phases, granular lithium disilicate having a grain diameter of about 0.3-1.5 .mu.m and granular lithium metasilicate having a grain diameter of about 0.3-0.5 m. U.S. Pat. No. 3,231,456 discloses a Sio.sub.2 --Li.sub.2 O--P.sub.2 O.sub.5 --MgO system glass-ceramic added with CuO and SnO ingredients which includes lithium disilicate and as a main crystal phase and alpha-quartz as a subsidiary crystal phase.
U.S. Pat. No. 3,977,857 discloses a SiO.sub.2 --Li.sub.2 O--MgO--P.sub.2 O.sub.5 --(Na.sub.2 O+K.sub.2 O) system glass-ceramic which is suitable as a material which adheres directly to a metal material. The U.S. Patent describes that the main crystal phase of this glass-ceramic is Li.sub.2 O.multidot.2SiO.sub.2.
Japanese Patent Application Laid-open No. Sho 63-210039 discloses a SiO.sub.2 --Li.sub.2 O--MgO--P.sub.2 O.sub.5 system glass-ceramic which is suitable for use as a magnetic disk substrate. This publication describes that the main crystal phases of this glass-ceramic are Li.sub.2 O.multidot.2SiO.sub.2 and alpha-cristobalite.
In the prior art Li.sub.2 O--SiO.sub.2 system glass-ceramics (Japanese Patent Application Laid-open No. Sho 62-72547, U.S. Pat. No. 3,232,456, U.S. Pat. No. 3,977,857 and Japanese Patent Application Laid-open No. Sho 63-210039, crystal phases grown are Li.sub.2 O.multidot.2SiO.sub.2 as a main crystal phase and a small amount of SiO.sub.2 ( alpha-cristobalite or alpha-quartz). In these prior art glass-ceramics, it is the Li.sub.2 O.multidot.2SiO.sub.2 crystal phase as the main crystal phase and not the alpha-quartz or alpha-cristobalite crystal phase that performs a principal function. These prior art glass-ceramics cannot provide, as a surface characteristic existing inherently in the glass-ceramics after polishing, the surface roughness of 15.ANG.-50.ANG. which is necessary for the CSS characteristic of a magnetic disk. For this reason, for improving the CSS characteristic required for a magnetic disk substrate, some texturing processing is required after the polishing process for making the surface of the glass-ceramic rough. This prevents a large scale production of a magnetic disk having the above described characteristics at a low cost.
For overcoming the above described disadvantages of the prior art magnetic disk substrates, the assignee of the present invention has found, as a result of studies and experiments made for the purpose of eliminating the above described disadvantages of the prior art magnetic disk substrates and providing a magnetic disk substrate made of a glass-ceramic which has an excellent surface characteristic after polishing by controlling the crystal structure and crystal grains of crystal grown in the glass-ceramic, and providing also a method for manufacturing the magnetic disk substrate, that a glass-ceramic obtained by subjecting a SiO.sub.2 --Li.sub.2 O--P.sub.2 O.sub.5 system glass including MgO as an essential ingredient to a heat treatment under a strictly limited temperature range has a microstructure in which alpha-quartz (alpha-SiO.sub.2) in the form of aggregated globular particles is randomly grown in a uniform crystal phase of lithium disilicate(Li.sub.2 O.multidot.2SiO.sub.2) and that, since this microstructure consists of the lithium disilicate phase which is mechanically and chemically instable and the alpha-quartz phase which is mechanically and chemically stable, projections and depressions are produced on the surface of the glass-ceramic substrate after polishing owing to mechanical and chemical actions produced by lapping and polishing processes, and that a magnetic disk substrate having an excellent surface characteristic after polishing can be obtained by controlling the diameter of the aggregated particles of alpha-quartz.
This magnetic disk substrate is one described in the specification of U.S. patent application Ser. No. 08/307,889 filed on Sep. 16, 1994 which is made of a glass-ceramic having lithium disilicate (Li.sub.2 O.multidot.2SiO.sub.2) and alpha-quartz (alpha-SiO.sub.2) as predominant crystal phases, in which grown crystal grains of alpha-quartz (alpha-SiO.sub.2) have a globular grain structure each consisting of aggregated particles, the globular grain have a diameter within a range of 0.3 .mu.m-3.0 .mu.m, and the surface roughness (Ra) of the surface the substrate after polishing is within a range of 15.ANG.-50.ANG.. The glass-ceramic substrate can be obtained by subjecting to a heat treatment a base glass consisting in weight percent of 65-83% SiO.sub.2, 8-13% Li.sub.2 O, 0-7% K.sub.2 O, 0.5-5% MgO+ZnO+PbO in which 0.5-5% MgO, 0-5% ZnO, 0-5% PbO, 1-4% P.sub.2 O.sub.5, 0-7% Al.sub.2 O.sub.3 and 0-2% As.sub.2 O.sub.3 +Sb.sub.2 O.sub.3.
In the CSS characteristic of a magnetic disk, the surface roughness (Ra) of the disk should be within the range of 15.ANG.-50.ANG. and the above described glass-ceramic developed by the assignee of the present invention can achieve this surface roughness of 15.ANG.-50.ANG. without the necessity for a mechanical or chemical texturing. However, decrease in the glide height necessary for increasing recording density of a magnetic disk cannot be automatically achieved by achieving the surface roughness of 15.ANG.-50.ANG..
The glide height is determined on the basis of surface roughness (Ra) and surface waviness (Wa) of the magnetic disk substrate. The glide height is lower as a value of each characteristic (Ra or Wa) is smaller. As an index indicating a limit value of glide height, GABP (glide avalanche break point, its unit being "microinch" (.mu.")) is currently employed. GABP presently required for a magnetic disk substrate is in the order between 1.0 .mu." to 1.5 .mu." but a smaller glide height will be required as a demand for a high density recording becomes stronger.
Polishing of glass-ceramics has been generally carried out by using a polishing material such as cerium oxide having a grain diameter of 1 .mu.m to 2 .mu.m which is generally used for polishing optical glasses. In the case of the above described glass-ceramic developed by the assignee of the present invention, however, glide height of GABP exceeding 0.8 .mu." only can be achieved by this conventional polishing method, though the surface roughness within the range of 15.ANG.-50.ANG. can be achieved. Thus, it has been found that it is difficult to achieve a glide height of GABP 0.8 .mu." or below by the conventional method and therefore the conventional polishing method cannot cope with the future requirement for a reduced glide height.
The invention has been made to overcome the above described problem arising in achieving by polishing of a glass-ceramic a very small glide height required for achieving a high density recording.
It is, therefore, an object of the present invention to provide a method for manufacturing a magnetic disk substrate made of glass-ceramic which can satisfy the requirement for reduction in the glide height which will occur in future.

Method for manufacturing a magnetic disk substrate


Managing network event information from a plurality of network appliances is disclosed. Each network appliance provides a network service and each has a version of a common database. Managing includes detecting network event information at a first network appliance, updating a version of the common database on the first network appliance with the network event information, and propagating the network event information to other versions of the database on other network appliances.

In a database grid, various events may be logged in order to better manage the system. For example, the system may be configured to log an event if a particular device in the network is overheating. When an event occurs on a node, an SNMP trap is typically sent from the node to an SNMP management node. The SNMP manager can then determine that an event has occurred. Centralized event management, in which only the management node has knowledge of events on other nodes, introduces delay and inefficiency in the system. In addition, having a single management node creates a single point of failure in the system. An improved method of event management is needed.


A new method for the detection and correction of environmentally induced functional interrupts (or “hangs”) induced in computers or microprocessors caused by external sources of single event upsets (SEU) which propagate into the internal control functions, or circuits, of the microprocessor. This method is named Hardened Core (or H-Core) and is based upon the addition of an environmentally hardened circuit added into the computer system and connected to the microprocessor to provide monitoring and interrupt or reset to the microprocessor when a functional interrupt occurs. The Hardened Core method can be combined with another method for the detection and correction of single bit errors or faults induced in a computer or microprocessor caused by external sources SEUs. This method is named Time-Triple Modular Redundancy (TTMR) and is based upon the idea that very long instruction word (VLIW) style microprocessors provide externally controllable parallel computing elements which can be used to combine time redundant and spatially redundant fault error detection and correction techniques. This method is completed in a single microprocessor, which substitute for the traditional multi-processor redundancy techniques, such as Triple Modular Redundancy (TMR).

During use, microprocessors may be exposed to external conditions which may cause internal data bits within or being processed by the microprocessor to change. Commonly, these events are classified as single event upsets (SEU). Conditions giving rise to SEU may include ambient radiation (including protons, x-rays, neutrons, cosmic rays, electrons, alpha particles, etc.), electrical noise (including voltage spikes, electromagnetic interference, wireless high frequency signals, etc.), and/or improper sequencing of electronic signals or other similar events. The effects of SEU conditions can include the processing of incorrect data or the microprocessor may temporarily or permanent hang, which may be reference to as single event functional interrupt (SEFI), for a temporary or permanent condition.
A number of solutions to avoid or correct for these events have been developed, and include modifying the manufacturing process for the microprocessor. For example, microprocessor may utilize temporal redundancy or spatial redundancy in an effort to mitigate the likelihood of SEUs. While these systems have proven somewhat effective in reducing or avoiding SEU and SEFI events, several shortcomings have been identified. For example, using spatial redundancy in a triple modular redundant design allows three microprocessors to operate in parallel to detect and correct for single event upsets and functional interrupts, but require two additional microprocessors and support circuits (e.g. memory) causing additional power and synchronization problems. Another solution is to manufacture the microprocessor integrated circuits (IC) on radiation tolerant processes, which historically lag commercial devices by two to three generations. More specifically, today's radiation-tolerant IC production processes produce devices utilizing 0.35 micrometer geometries while non-radiation tolerant devices typically utilize 0.13 micro-meter geometry. The effect of the larger geometry is much slower performance and higher power consumption for the microprocessor.
In light of the foregoing, there is an ongoing need for high performance, low power consumption radiation tolerant systems and devices, that mitigate the problem of single event functional interrupt (SEFI), also known as environmental induced hangs.

Functional interrupt mitigation for fault tolerant computer


A fishing lure is generally provided that incorporates a hook stabilizing device that substantially holds the hook in place and hinder the hook from rotating while the lure is being fished. The hook stabilizing device is configured to accept the connection a fishing line to a hook, such as a crimp connection to an eyelet of a hook. Free rotation of the hook may be allowed after a fish is hooked when the connection of the line to the hook is removed from the hook stabilizing device while fighting the hooked fish.

Sport fishing is enjoyed around the world. From fresh water to salt water, a wide variety of fish species exist. Fishermen employ a variety of equipment and tackle depending upon the water being fished, the time of day, the species of fish sought, personal choice, and many other factors. A fishing lure, sometimes referred to as an artificial lure, is frequently a part of such equipment and tackle.
Fishing lures are typically designed and decorated with the goal of replicating or mimicking the movement and appearance of a food source for the particular fish being sought. For example, such lure may take on the shape of a minnow, tadpole, frog, mouse, insect, salamander, another fish, or such other food source. The fisherman's hope is that by having a lure closely resembling or acting like a source of food, fish will be enticed into biting the lure.
In an effort to make the lure aesthetically realistic, a designer can use materials pigmented with the desired colors. For example, colored plastics or rubber may be used. In addition, a designer can paint or stain the external surface of the lure to achieve the desired color and marking characteristics. Decorative features such as scales, eyes, and fins may be painted onto the surface or otherwise added to the lure.
Lures can also be designed with features that make the lure realistic in a functional manner. Fins, diving planes, spinners, rattles and the like may be added in order to make the lure move and sound like a food source. Some lures may be specifically designed to operate on the water surface while others may function only when below.
Typically, fishing lures are designed to incorporate at least one hook somewhere within or attached to the fishing lure. In some lures, it may be desired that the hook not rotate or move freely with respect to the lure so as to prevent the hook from excessive movement that may discourage a targeted fish from striking the lure. Also, by preventing the hook from rotating freely with respect to the lure body, the hook can stay in the desired position and angle to better ensure that a striking fish will be hooked. Furthermore, in embodiments where the leader line is connected directly to the hook, preventing the hook from rotating will prevent build up of unwanted twist in the leader line and the fishing line. However, controlling the movement of the hook relative to the lure is difficult, especially when the hook is attached to a fishing line that extends through the lure body and out the back or bottom of the body. Typically, the lure does not prevent the hook from rotating or moving freely with respect to the lure body.
Also, it may be desired to have the lure body move away from the hook, up the fishing line toward the fisherman, while fighting a hooked fish. This movement allows the hook to rotate freely with the hooked fish's movement, while preventing the lure body from dislodging the hook out of the fish's mouth.
As such, a need exists for a device that prevents the hook from rotating freely with respect to the lure while being fished, but still enables the hook to rotate freely when fighting a hooked fish.

Hook stabilizing device for a fishing lure


A hybrid drive device has an internal combustion engine, a clutch transmission which has at least one free partial transmission and a partial transmission connected to an electric machine with in each case a clutch, and at least one electric machine. In order to start the internal combustion engine, pulse energy is provided from an inertia of the clutch associated with the free partial transmission and/or a rotation in the free partial transmission.

The invention relates to a method for operating a hybrid drive apparatus of a motor vehicle, to a hybrid drive apparatus, and to a motor vehicle.
In the case of hybrid vehicles, the internal combustion engine can be started via crank starting, an electric machine providing a positive torque via a clutch, which positive torque acts on the internal combustion engine or the crankshaft. It is also possible to start the internal combustion engine by means of a pinion starter. While the internal combustion engine is being brought to a connector rotational speed, a load request of a driver of the hybrid vehicle cannot be implemented sufficiently by the electric machine, for example. This can lead to a situation which is unacceptable for the driver. Moreover, a start of this type of the internal combustion engine requires a large amount of energy which has to be provided by the electric motor of the hybrid vehicle.
It is an object of the present invention to shorten the time duration until the beginning of a power transmission of the internal combustion engine, and to reduce the requirement of electric energy for the additional starting.
In the case of current hybridized double clutch transmissions, with a connection of the electric machine to a component transmission, problems can arise for rapid starting of a switched-off internal combustion engine when exiting from phases with a switched-off internal combustion engine. In the case of the change, in particular, from electric driving, that is to say merely by way of the drive of an electric machine, into hybrid driving, in which the vehicle drive takes place both via the electric machine and via the internal combustion engine, it can take a certain amount of time until the internal combustion engine has the required connector rotational speed. These are typically hybrid vehicles, in the case of which applications are operated in the low voltage range, that is to say below 60 V, or else in the case of hybrid vehicles with high voltage applications, that is to say greater than or equal to 60 V.
Starting of the internal combustion engine is triggered by way of a load request at the accelerator, a request when the brake pedal is released, or as a result of the general operating strategy. Here, operating strategies up to now use a suitable starting system, according to which the internal combustion engine is started, proceeding from the rotational speed 0, by means of crank starting or else via a pinion starter of the internal combustion engine. Subsequently, by way of combustion of fuel, the internal combustion engine is brought to a connector rotational speed for output, and is only then coupled to the drive train and can contribute to the acceleration of the vehicle.
A time period often occurs here, which time period can lead to functional deficits and unacceptable vehicle reactions with regard to the driver requests without a sufficient implementation of the load request of the driver and a high consumption of electric energy for bridging purposes until the internal combustion engine takes over the load.
According to the invention, the object is achieved by way of a method for operating a hybrid drive apparatus of a motor vehicle. The hybrid drive apparatus comprises an internal combustion engine, a clutch transmission, having at least one free component transmission and one electric component transmission with in each case one clutch, and at least one electric machine. The electric machine is arranged on at least one component transmission, at least one other component transmission acting without a connection of the electric machine. The method comprises the following steps: opening of the at least two clutches for switching off the internal combustion engine; driving or recuperation of the motor vehicle via the electric component transmission. Receiving of an additional starting request for the internal combustion engine. Closing of the clutch which is assigned to the free component transmission for starting of the internal combustion engine, pulse energy from an inertia of the clutch which is assigned to the free component transmission and/or a rotation in the component transmission being provided for starting of the internal combustion engine.
The free component transmission does not have a connection to the electric machine. The electric component transmission has a connection to the electric machine. The two component transmissions have in each case one clutch to the internal combustion engine, or the two component transmissions are assigned in each case one clutch to the internal combustion engine.
In some exemplary embodiments of the invention, the hybrid drive arrangement corresponds to what is known as a P2 arrangement on one of the two component transmissions of a double clutch transmission topology. The clutch transmission is configured with multiple gears and such that it can be shifted in an automated manner. The clutch transmission can have a plurality of component transmissions. At least one of the component transmissions has a connection to an electric machine and is called an electric component transmission. At least one other component transmission does not have a connection to the electric machine and is called a "free component transmission". The two component transmissions can be coupled to the internal combustion engine via in each case one clutch which is assigned to the component transmission. Here, the clutches of the component transmissions can be actuated independently of one another.
In some exemplary embodiments, the starting point of the method is the entry of the motor vehicle into a phase of driving with a switched-off internal combustion engine. Here, the at least two clutches of the at least two component transmissions (electric component transmission and free component transmission) are open, in order for it to be possible for the internal combustion engine to be switched off to a rotational speed which equals zero or approximately equals zero. During this, the drive of the motor vehicle can be brought about via that component transmission which has a connection to the electric machine. The vehicle is either driven in a purely electric manner, or is in a recuperation phase.
If a control unit of the hybrid drive apparatus then receives an additional starting request for the internal combustion engine, the free component transmission which does not have a connection to the electric machine is opened toward the output by way of disengagement of the gear (disengagement of the shifting element), and the clutch to the internal combustion engine is closed, as a result of which the internal combustion engine is started. Here, starting of the internal combustion engine takes place using pulse energy in a pulse starting method. The required energy is provided from the inertia of the masses of the free component transmission and the associated clutch, and possibly present further rotating inertias (torsional non-uniformity dampers). The rotational energy which is present in the free component transmission is used for pulse starting.
In order for it to be possible for the pulse energy to be utilized without having a reaction on the output, a shifting element which forms the gear can be opened in the free component transmission before pulse starting. This can take place by way of opening of the shifting element in the free component transmission in order to decouple with respect to the output. The opening of the shifting element can take place before the closing of the clutch which is assigned to the free component transmission.
In other words, a method or an operating strategy for a pulse starting method for the internal combustion engine starting of a hybrid vehicle is specified, for the exit from phases of the engine-off recuperation and the electric driving. In particular, the pulse starting method is used in the case of motor vehicles having a hybrid drive apparatus with a double clutch transmission.
The measures according to the invention indicate a method which is distinguished by the fact that the time duration until the beginning of the power transmission of the internal combustion engine is substantially shortened. It is made possible as a result that, in particular in the case of transmission topologies on a double clutch basis, the starting request is met more rapidly and the use of electric energy for the vehicle propulsion is restricted. Moreover, the driving comfort also increases. The customary starting systems for the internal combustion engine, such as crank starting or pinion starting, can be dispensed with or, if desired, are used as an additional starting system.
In one development, the method comprises the setting of the free component transmission to at least one gear below the gear of its electric component transmission. The setting of the free component transmission can be set in a manner which is dependent on a possibly present driver request to one gear below the electric component transmission. The component transmission (free component transmission) which is not used for driving purposes and has a connection to the output forms at least one gear below the gear in the electric component transmission by way of closing of shifting elements. The aim here is to elevate the secondary side of the clutch (which belongs to the free component transmission) to a higher rotational speed level than that of the clutch which belongs to the electric component transmission. As a result, a provision of pulse energy from the inertia of the clutch and the rotation in the free component transmission is provided, which lies at a higher level than in the electric component transmission.
In one development of the method, the setting of the gear takes place continuously. In order to provide the necessary pulse starting energy for the internal combustion engine, in each case at least one gear below the electric component transmission is set continuously in the free component transmission parallel to the above-described shifting strategy (gear in the free component transmission at least one gear below the gear in the electric component transmission) during the recuperation or the electric driving by means of the drive via the electric machine.
It is provided in one development of the method that a rotational speed difference which is provided in the free component transmission is sufficient for starting of the internal combustion engine by means of pulse energy. By way of setting of the gear in the free component transmission, which can take place continuously, it is ensured that a rotational speed difference of this type prevails in the free component transmission, from which rotational speed difference the starting of the internal combustion engine in accordance with the pulse starting method can take place at any time by way of closing of the associated clutch of the free component transmission.
In one development, the method comprises accelerating of the internal combustion engine to a rotational speed which is equal to a compression ignition rotational speed. When the additional starting request is received, the free component transmission is first of all interrupted toward the output by way of opening of a gear-forming shifting element, and subsequently the associated clutch for starting the internal combustion engine is closed. In some exemplary embodiments, the internal combustion engine is accelerated to a rotational speed which is necessary for compression ignition on the basis of the pulse energy. Subsequently, independent running up of the internal combustion engine to a synchronous rotational speed of the electric component transmission takes place.
It is provided in one development of the method that the clutch of the electric component transmission is closed if the rotational speed of the internal combustion engine is equal to a synchronous rotational speed. When the synchronous rotational speed is reached, the clutch of the electric component transmission is closed, and the propulsion of the motor vehicle can be ensured via the internal combustion engine.
In one development, the method comprises accelerating of the internal combustion engine to a rotational speed which is above a target rotational speed for connecting to the electric component transmission. When the additional starting request is received, the free component transmission is interrupted toward the output by way of opening of the gear-forming shifting element, and subsequently the associated clutch for starting the internal combustion engine is closed. In some exemplary embodiments, the pulse starting is configured in such a way that the rotational speed which is set between the connected internal combustion engine and the free component transmission is set above the target rotational speed for the connection to the electric component transmission.
One development of the method does not rule out a connection of the internal combustion engine to the free component transmission. This can be dependent on the operating strategy, however.
An optimally set pulse energy leads to pulse starting with the idling rotational speed of the internal combustion engine being reached.
It is provided in one development of the method that the driving via the electric component transmission comprises propulsion of the motor vehicle and/or recuperation of brake energy. Here, the phases of recuperation and propulsion by way of the electric machine take place via the electric component transmission.
The result of said operating strategy for the method according to the invention and the hybrid drive apparatus is the more rapid connection of the internal combustion engine to the output for a rapid implementation of driver requests and/or operationally strategic necessities. At the same time, the recuperation potentials can be increased, which recuperation potentials occur when the drag torque of the coupled internal combustion engine does not have to be overcome in brake recuperation phases.
Furthermore, a hybrid drive apparatus according to the invention of a motor vehicle is specified. The hybrid drive apparatus comprises an internal combustion engine, a clutch transmission, having at least one free component transmission and one electric component transmission with in each case one clutch, and an electric machine which is arranged on the electric component transmission. Pulse energy from the inertia of the clutch which is assigned to the free component transmission and/or rotation in the component transmission is provided for starting of the internal combustion engine.
Furthermore, a motor vehicle according to the invention, in particular a passenger motor vehicle, is specified for the application of the method, the motor vehicle having a hybrid drive apparatus which comprises an internal combustion engine, a clutch transmission and an electric machine.
Specific embodiments of the invention will now be described with reference to the appended drawings. This invention can be configured in many different forms, however, and should not be interpreted as being limited to the embodiments which are shown here; rather, said embodiments are provided, in order that this disclosure is thorough and complete, and they completely cover the scope of protection of the invention for a person skilled in the art. The terminology which is used in the detailed description of the embodiments which are shown in the appended drawings is not intended to be restrictive for the invention. Identical designations refer to identical elements in the drawings.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.

Pulse start method for an internal combustion engine of a hybrid vehicle

Bayerische Motoren Werke Aktiengesellschaft


A method of managing additional filters in a navigation system fitted to a vehicle, the system acting, during a journey of the vehicle, to deliver at least one position of the vehicle by using a main filter for merging data coming from a constellation of visible satellites present above a vehicle horizon, each additional filter excluding data coming from one of the satellites in order to obtain a corrected position in the event of failure of the excluded satellite. The steps including from a position of the vehicle, determining a theoretical constellation of satellites present above the horizon; and for each satellite present in the theoretical constellation, creating and maintaining an additional filter excluding that satellite.

During a flight of the aircraft, such a navigation system serves to calculate successive positions of the aircraft by making use of a main filter for merging data coming from a constellation of visible satellites that are present above a horizon of the aircraft, and possibly also data coming from an inertial navigation unit or the like on board the aircraft. It is recalled that the horizon is the line separating that which is masked from the aircraft by the curvature of the earth from that which is not masked thereby. With the GPS system, some maximum number of satellites can be present above the horizon of an aircraft (i.e. there will be some maximum number of satellites that are not masked from the aircraft by the curvature of the earth), and this number is about ten. However, it is not unusual for geographical relief or a portion of the aircraft to mask one or more of the satellites. Nevertheless, the navigation system remains operational providing it has data available from at least four satellites making up the constellation of visible satellites. The navigation system is found to be particularly accurate when the satellites are operating correctly, however its performance falls off quickly as soon as one of the satellites presents a failure that affects the validity of the data it transmits.
To remedy that problem, the navigation system also calculates corrected positions from additional filters, each of which excludes data coming from one of the satellites. When failure of one of the satellites is detected, the additional filter that excludes that particular satellite becomes the main filter, and the other additional filters are initialized from the new main filter.
The creation of additional filters is triggered by detecting a new satellite. Thus, as soon as the data coming from a satellite reaches the navigation system, an additional filter excluding that satellite is created and the satellite is incorporated in the existing additional filters. When the navigation system no longer detects data coming from that satellite, the corresponding additional filter is deleted. Unfortunately, when satellites are masked by geographical relief or by a portion of the aircraft, the data transmitted by the masked satellites no longer reach the navigation system, thereby causing the corresponding filters to be deleted, which filters will be recreated when the satellites are no longer masked and data from them again reaches the navigation system. Managing additional filters is particularly burdensome and constitutes a major computation load for the navigation system.

Method of managing additional filters in a satellite navigaiton system


A process for biologically producing an .alpha.-hydroxyamide or an .alpha.-hydroxy acid represented by formula (III) ##STR1## wherein R represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group or a substituted or unsubstituted and saturated or unsaturated heterocyclic group; and X represents an amido group or a carboxyl group, comprising reacting an .alpha.-hydroxynitrile represented by formula (I): ##STR2## wherein R is as defined above, or a mixture of an aldehyde represented by formula (II): EQU R--CHO (II). wherein R is as defined above, and hydrogen cyanide with a microorganism capable of producing such an amide or acid from the corresponding .alpha.-hydroxynitrile is disclosed, in which the reaction system contains a sulfite ion, a disulfite ion or a dithionite ion. The enzymatic activity of the microorganism lasts for an extended period of time.

Known biological processes for producing an .alpha.-hydroxyamide include a process comprising reacting lactonitrile, hydroxyacetonitrile, .alpha.-hydroxymethylthiobutyronitrile etc. with a microorganism belonging to the genus Bacillus, Bacteridium, Micrococcus or Brevibacterium to obtain a corresponding amide as disclosed in JP-B-62-21519 (corresponding to U.S. Pat. No. 4,001,081) (the term "JP-B" as used herein means an "examined published Japanese patent application"). It is also reported in Grant, D. J. W., Antonie van Leeuwenhoek; J. Microbiol. Serol. Vol. 39, p. 273 (1973) that hydrolysis of lactonitrile by the action of a microorganism belonging to the genus Corynebacterium to produce lactic acid involves accumulation of lactamide as an intermediate.
Known biological processes for producing an .alpha.-hydroxy acid include a process for obtaining glycolic acid, lactic acid, .alpha.-hydroxyisobutyric acid etc. from the corresponding .alpha.-hydroxynitrile by the action of a microorganism of the genus Corynebacterium (see JP-A-61-56086, the term "JP-A" as used herein means an "unexamined published Japanese patent application"), a process for obtaining lactic acid, glycolic acid etc. from the corresponding .alpha.-hydroxynitrile by using a microorganism of the genus Bacillus, Bacteridium, Micrococcus or Brevibacterium (see JP-B-58-15120, corresponding to U.S. Pat. No. 3,940,316), a process for obtaining lactic acid, .alpha.-hydroxyisobutyric acid, mandelic acid, .alpha.-hydroxybutyric acid, .alpha.-hydroxyvaleric acid, .alpha.-hydroxy-.alpha.-phenylpropionic acid, .alpha.-hydroxy-.alpha.-(p-isobutylphenyl)propionic acid etc. from the corresponding .alpha.-hydroxynitrile by using a microorganism of the genus Pseudomonas, Arthrobacter, Aspergillus, Penicillium, Cochliobolus or Fusarium (see JP-A-63-222696) and a process for obtaining .alpha.-hydroxy-.beta.,.beta.-dimethyl-.gamma.-butyrolactone from the corresponding .alpha.-hydroxynitrile by using a microorganism of the genus Arthrobacter. Aspergillus, Bacillus, Bacteridium, Brevibacterium, Cochliobolus, Corynebacterium. Micrococcus, Nocardia. Penicillium, Pseudomonas or Fusarium (see JP-A-64-10996).
It is known, however, that an .alpha.-hydroxynitrile is, more or less, partially dissociated into the corresponding aldehyde and hydrogen cyanide in a polar solvent as taught in V. Okano et al., J. Am. Chem. Soc., Vol. 98, p. 4201 (1976). Since an aldehyde generally is bound to proteins to deactivate enzymes as described in G. E. Means et al. (ed.), Chemical Modification of Proteins, p. 125, Holden-Day (1971), enzymatic hydration or hydrolysis of an .alpha.-hydroxynitrile is accompanied with the problem that the enzyme is deactivated in a short time. It therefore has been difficult to obtain an .alpha.-hydroxyamide or an .alpha.-hydroxy acid in high concentration with high productivity.

Biological process for producing .alpha.-hydroxyamide or .alpha.-hydroxy acid


A frame holder for a stereotactic frame holds the stereotactic frame in proper alignment with the head coil of an imaging unit so the reference markers on the stereotactic frame are properly aligned with the axis of the head coil. The frame holder has a base member that receives the base ring of the stereotactic frame so the frame holder and the stereotactic frame are locked together with proper alignment of the reference markers. A top member is spaced from the base member, and has a support block to carry the weight of the stereotactic frame. Posts fix the top member to the base member. The base and top member are sized and shaped to be snugly, slidably received within the opening in the head coil.

1. Field of the Invention
This invention relates generally to stereotactic frames for use in stereotactic surgery, and is more particularly concerned with a frame holder for positioning a stereotactic frame with respect to an imaging system.
2. Description of the Prior Art
Stereotactic surgery requires that a particular point, for example in the head, be located by coordinates in three dimensional space. Currently, this is accomplished through the use of a stereotactic frame which has a coordinate system in conjunction therewith. With the patient in the stereotactic frame, images are made of the patient, using computer aided tomography (CAT), magnetic resonance imaging (MRI) or some comparable imaging system. The reference marks specifying the coordinate system of the stereotactic frame are visible on the images permitting calculation of coordinates of a chosen point.
Those skilled in the art will understand that the stereotactic frame defines a volume of three dimensional space, thereby allowing a positional description of any point in that defined volume to be made via the specified coordinate system. As a result, the surgeon must rely on the coordinate system to compute the precise location intended for surgery. It will therefore be understood that the attitude of the stereotactic frame with respect to the imaging device is important. A misalignment between the stereotactic frame and the imaging device will cause the coordinate reference markers on the stereotactic frame to be misaligned in the images. The mathematics of calculating the coordinates of a given point in the space defined by the stereotactic frame are significantly more complex without proper alignment of the stereotactic frame and the imaging system.
In making images of a patient's head using MRI, the head is placed within a "head coil" which is a transceiver for the radio-frequency (RF) signals of interest. The head coil defines a central opening for receiving the patient's head, and for receiving the head with a stereotactic frame thereon for stereotactic surgery. It is here that alignment is important. The stereotactic frame is preferably precisely aligned with the head coil in order to facilitate coordinate calculation.
The usual efforts at aligning a stereotactic frame with the head coil comprise attempting to prop up various portions of the frame with towels or the like. It will be understood that the material used must be carefully selected. Metals will redirect, or shield, the signals of interest, and numerous other materials will produce signals of their own. Ferrous metals cannot safely be placed in the room holding the MRI scanner due to the strength of the corresponding magnetic field and the risk of resulting movement. Thus, towels are commonly used in attempts to hold the frame in place. Since towels are deformable, they must be packed carefully. Even so, the frame frequently moves with respect to the head coil after imaging has begun. A shift in the frame may render calculation more difficult if the shift is before the actual scan, or may require a new scan if the shift is during the scan.


A memory controller performs a reference read on a plurality of memory cells using reference read voltages, generates a histogram indicating the number of memory cells in different threshold voltage bins based on results of the reference read, estimates actual read voltages based on the histogram and a first estimation function, and reads data using the actual read voltages. When reading of the data with the actual read voltages estimated using the first estimation function fails, the memory controller estimates actual read voltages using a second estimation function different from the first estimation function and reads the data with the actual read voltages estimated using the second estimation function.

There is known a memory system including a non-volatile memory cell. In a read operation in this memory system, based on a comparison between a threshold voltage of the memory cell and a read voltage, data stored in the memory cell is determined.
There are various factors that cause changes in memory cell threshold voltage. The memory system is configured to be capable of changing the read voltage so that correct data can be read from the memory cell even when the threshold voltage of the memory cell changes.


A plurality of detection units are connected respectively in parallel with a plurality of battery cells connected in series. The detection units each include an inductor and a zener diode connected in series. A battery checker includes a plurality of detection inductors and a single voltmeter that form a closed circuit. A plurality of detection inductors are arranged so that they are magnetically coupled respectively with the inductors of the plurality of detection units. Each zener diode is connected with the polarity to be reverse biased by the output voltage of the battery cell. Respective breakdown voltages of the zener diodes are set higher than the output voltage of each battery cell in normal use and different in a stepwise manner from each other.

Whether or not a secondary battery is degraded is commonly determined based on the output voltage of the secondary battery. For example, Japanese Patent Publication No. 1-33787 (PTL 1) discloses that an abnormal state of a battery system is detected based on the battery voltage when the engine is started. Specifically, when the engine is started at a low engine temperature and accordingly the battery voltage decreases, degradation of the performance of the battery is detected. As seen from the above, the battery is commonly inspected based on the output voltage.

Secondary battery, inspection apparatus and inspection method for secondary battery, and battery inspection system


It is intended, in the mobile information terminal, to achieve compactization, cost reduction and reduction in the burden of information processing, while taking the enciphering process for the information into consideration.

1. Field of the Invention
The present invention relates to an information communication apparatus having cipher processing function, a method, an information communication system and a memory medium therefor.
2. Related Background Art
The information communication apparatus, represented by mobile communication terminal, has shown remarkable progress in compactization, higher performance and higher speed in information processing, and there are already commercialized mobile communication terminals that are comparable in performance to the desk-top computers. Because of such tendency, the mobile communication terminals are rapidly becoming popular in the business field, in enabling rapid information exchange by wireless communication even when one is not in the office. In such form of communication, the leak of secrecy is always a major concern. Therefore the corporations engaged in the development of the information communication apparatus are actively the development of cipher process technology of the transmitted information.
On the other hand, the amount of the processed information is rapidly growing, such as taking, fetching and transmitting the digital image in the communication function, and the performance required for the information signal processing unit will become even larger, as the moving image will also be processed in the future. Furthermore, the mobile communication terminal integrating the digital camera for image fetching has been recently commercialized and the mobile communication terminal including the digital video camera will also appear in the near future.
However, because of such advancement in the performance of the mobile information terminal, it is increasingly becoming difficult to achieve compactization important for mobility, in comparison with the conventional products provided solely with the communication function of the information editing function. In order to additionally include the cipher process in the above-described situation, it is important not only to increase the information processing speed but also to reduce the dimension of the entire information communication apparatus including the cipher processing device.
As explained in the foregoing, the current issues associated with the information communication apparatus are the cost increase resulting from the increase in the performance, the enormous increase in the amount of information to be handled, including images, and the difficulty in compactization particularly in the mobile terminal or the like.
Also the apparatus capable of cipher process is recently attracting attention, and various communication apparatus with the enciphering means are expected to be commercialized in the future. On the other hand, in the home use, the level of secrecy of the information to be handled is relatively low, so that the enciphering process may not be essential. However, if the enciphered information is always transmitted, the receiving side has to be equipped with the deciphering device for reading the enciphered information. As a result, the increase in the dimension of the apparatus, in the cost and in the burden for the information processing is unavoidable in the transmitting side and in the receiving side.

Information communication apparatus and method, information communication system, and memory medium

Abstract: The cipher signal process unit for enciphering the transmission information and the cipher process selection unit for selecting whether or not to use the cipher signal process unit are provided to select whether or not to execute the enciphering of the transmission information, according to the necessity in executing the communication of information, thereby dispensing the enciphering process as far as possible and alleviating the burden of the process involved in the enciphering. Also by executing the enciphering or not respectively in case the deciphering is possible or not in the information receiving side, the cipher process means may be dispensed with in the information communication apparatus of the receiving side, whereby the apparatus of the receiving side can be made less expensive and smaller.


A compact adjustment knob for an optical, mechanical, or electronic device includes a spindle supported on the device for rotation about an axis to control a setting of the device, and a releasable automatically locking lock mechanism supported on the spindle for rotation therewith. The lock mechanism includes at least one manually depressible button accessible on an outer surface of the adjustment knob and connected to an actuator shaft that extends inwardly through a drive hole in an outer side wall of the spindle so that a force manually applied to the button is transmitted by the actuator shaft to drive the lock mechanism and rotate the spindle. The lock mechanism may include a lock sleeve that is biased to a normally locked position and driven along the axis by the actuator shaft when the button is depressed.

Rotatable adjustment knobs or control knobs are commonly utilized to adjust settings of optical, mechanical, and electrical devices. Riflescopes and similar weapon aiming devices commonly include a pair of orthogonally mounted rotatable adjustment knobs, also known as turret knobs or simply turrets, which are used for adjusting elevation and windage settings affecting the respective vertical and horizontal aim of the riflescope, and thus of the weapon to which the riflescope is attached. Rotating adjustment knobs are also commonly used on riflescopes and other optical devices for adjusting focus, reticle illumination intensity, display settings, display illumination, and other settings of the device. Rotating adjustment knobs are also used on various other optical, electronic, and mechanical devices, such as spotting scopes, binoculars, microscopes, stereos and radios, appliances, automobile controls, and measurement instruments, for example.
In some applications, it is advantageous for an adjustment knob to automatically lock in place to prevent inadvertent adjustment. U.S. Pat. No. 8,006,429, issued Aug. 30, 2011, describes various locking turret knobs for riflescopes, some of which are normally locked, but may be unlocked by applying a releasing force to the knob or a component thereof, then rotating the knob to make an adjustment. In some embodiments described in the '429 patent, when the manual force is removed a spring or other biasing device of the knob automatically returns the locking mechanism to its normally locked state, preventing inadvertent rotation of the adjustment knob, for example during transit or other handling.
Patent Application Publication No. US 2011/0100152 A1 describes an auto-locking adjustment mechanism including a pair of buttons on opposite sides that are manually depressed with a pinching action to release the locking mechanism and allow the knob to be rotated for adjustment of a setting of a riflescope or other device. When force is released from the buttons, the device automatically locks. Hence, the adjustment mechanism is sometimes referred to as a pinch-and-turn adjustment knob or a pinch/turn knob. The buttons are carried by a knob body that is installed over and frictionally secured to a threaded spindle of the device by a pair of set screws. The knob carries an indicator ring marked to provide a visual indication of the rotational position of the knob relative to the riflescope. The zero position of the knob can be adjusted relative to the spindle by loosening the set screws, rotating the knob until a zero marking on the indicator ring is aligned as desired relative to the riflescope main tube, then re-tightening the set screws. Each of the buttons carries an actuator shaft that extends radially through a bore in the side of the knob body and operatively engages a linkage within the mechanism that is driven in an axial direction when the buttons are depressed to release the locking mechanism, allowing the knob body and spindle to be rotated together to drive a threaded adjustment screw plunger or another type of adjustment device.
The present inventor has recognized a need for an improved auto-locking pinch/turn adjustment knob.

Low profile auto-locking pinch/turn adjustment knob


In a method of manufacturing a semiconductor device, laminate structures with a first insulating film as a top film are formed on a semiconductor region having a first conductive type. One of the laminate structures is a gate electrode structure including a second insulating film as a gate insulating film formed on the semiconductor region, a conductive layer as a gate electrode formed on the gate insulating film, and the first insulating film formed on the gate electrode. Next, side wall insulating films are formed on side walls of the gate electrode structure and laminate structures adjacent to the gate electrode structure. Ion implantation of impurity of a second conductive type different from the first conductive type is executed using the side wall insulating films in a self-alignment manner to produce the source/drain regions for a metal-oxide-semiconductor (MOS) transistor. Contacts are formed for source/drain regions formed between the gate electrode structure and the adjacent laminate structures, using the side walls in a self-alignment manner.

1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for manufacturing a semiconductor device with contacts formed in self-alignment manner.
2. Description of Related Art
A semiconductor integrated circuit formed on a semiconductor substrate such as a silicon substrate has been developed to be integrated with higher density. In a static random access memory (SRAM) as one of such integrated circuits, the memory capacity is increased from 4 Mbits to 16 Mbits and from 16 Mbits to a further more bits. In addition to the high density integration, high speed operation and low power consumption are required in the SRAM. In a large scale integrated circuit inclusive of not only the SRAM but also the dynamic random access memory (DRAM), many semiconductor elements need to be formed on a chip. The chip size needs to be reduced as small as possible from the viewpoints of the device cost and the product yield.
In the SRAM which has a complicated memory cell structure and needs fine processing, the chip size depends on the size of a memory cell. Therefore, in order to reduce the chip size, it is necessary to reduce the size of the memory cell. Specifically, it is very important to reduce the margin of a contact hole for a semiconductor circuit pattern in the memory cell, because many patterns such as diffusion layer patterns of transistors, gate electrode patterns, power supply line patterns and element isolation insulating film patterns, are formed in the memory cell and there are many contacts between these patterns. For this reason, it is desirable to form the contact holes in the semiconductor circuit pattern in self-alignment manner.
FIG. 1 is a plane pattern diagram of a conventional SRAM memory cell. This memory cell of a CMOS type is composed of 6 MOS transistors. FIGS. 2A to 2F are cross sectional views cut along a line A-A' of the SRAM memory cell shown in FIG. 1 in the manufacturing processes.
Referring to FIG. 1, active regions 102-1, 102-2, 103-1 and 103-2 surrounded by an element isolation insulating film 101-1 are formed on a P-type semiconductor (silicon) substrate or P-type well. Then, a gate electrode 104-1 for a drive MOS transistor and a gate electrode 104-2 for a load MOS transistor are provided and a word line 105-1 functioning as a gate electrode for a transfer MOS transistor is provided. N-type diffusion layers are formed as source/drain regions of the drive MOS transistor and load transfer MOS transistor by performing ion implantation of arsenic atoms as impurity into regions of the silicon active regions 102-1 and 102-2 where the above gate electrodes are not formed. Boron atoms as impurity are introduced by ion implantation into regions of the silicon active regions 103-1 and 103-2 where the gate electrodes are not formed, such that P-type diffusion layers are formed as the source/drain regions of the load MOS transistor. Thereafter, an interlayer insulating film is formed to cover the entire surface. Contact holes 106-1 and 106-2 for connecting to the ground potential are formed to pass through the interlayer insulating film. Source regions of the drive MOS transistors are connected to the ground potential wiring patterns (not shown) via the contact holes 106-1 and 106-2. Contact holes 108-1 and 108-2 for connecting to power supply potential pattern are formed and the power is supplied to the load MOS transistors via the contact holes 108-1 and 108-2. Subsequently, contact holes 107-1, 107-2, 109-1 and 109-2 are formed and contacts 107-1 and 109-1 are connected by a pattern (not shown). As a result, the drain region of the drive MOS transistor, the load/drive gate electrode 104-2 and the drain region of the load MOS transistor are electrically connected. Similarly, a pattern (not shown) is formed between the connection contact holes 107-2 and 109-2. As a result, the drain region of the load MOS transistor, the load/drive gate electrode 104-1 and the drain region of the drive MOS transistor are electrically connected. Further, contact holes 110-1 and 110-2 for bit lines are formed.
In this manner, at least 10 contact holes are required in the conventional CMOS type static memory cell as shown in FIG. 1. The connection contact hole 107-1 is formed over the drain region of the drive MOS transistor formed in the silicon active region 102-1 and the gate electrode 104-2. Similarly, the connection contact hole 109-2 is formed over the drain region of the load MOS transistor formed in the silicon active region 103-2 and the gate electrode 104-1.
Next, a method of forming the contact holes will be described with reference to FIGS. 2A to 2F. Referring to FIG. 2A, an element isolation insulating film 202 is selectively formed on the surface of a silicon substrate 201. Subsequently, a gate insulating film 203 is formed for the load MOS transistors. Then, polyside film 204 is deposited and the first resist mask 205 is formed. Next, the polyside film 204 is etched by a dry etching method using the first resist mask 205. Thus, load/drive gate electrodes 206 and 206a are formed as shown in FIG. 2B.
Next, a silicon oxide film is deposited on the entire surface and then anisotropic etching is executed wholly by a dry etching method. As a result, side wall insulating films 207 are formed on the side wall of the load/driving gate electrodes 206 and 206a, as shown in FIG. 2C. Subsequently, P-type diffusion layers 208 are formed through ion implantation of boron and heat treatment. The P-type diffusion layers 208 function as the source/drain regions of the load MOS transistor.
Next, as shown in FIG. 2D, an interlayer insulating film 209 is formed. Then, the second resist mask 210 is formed. The interlayer insulating film 209 is etched by a dry etching method using the second resist mask 210 to form contact holes. A contact hole overhanging the load/drive gate electrode 206a and the diffusion layers 208 is also formed. This contact hole corresponds to the connection contact hole 109-2 in FIG. 1.
Next, as shown in FIG. 2E, a metal thin film 211 is formed and the third resist mask 212 is formed. The metal thin film 211 is etched by a dry etching method using the third resist mask 212. As a result, connection pattern 108-2, 109-2, 109-1 and 108-1 are formed as shown in FIG. 2F.
In the conventional method of forming the contacts, as described above, it is difficult to form the side wall insulating films on the side walls of the gate electrode of the MOS transistor and to form the contact holes on the source/drain regions of gate electrode of the MOS transistor. For this reason, in a case of high density SRAM in which many contact holes are to be formed, it is difficult to reduce the size of a memory cell.

Semiconductor device with contacts formed in self-alignment