Abrasive sheet materials, abrasive sheet materials with island distributions of abrasive particles, processes for manufacture of abrasive sheet materials with minimized abrasive content, processes for attaching abrasive particles exclusively on the top surface of raised islands in monolayers, and processes for attaching raised island foundation structures to inexpensive flexible backing sheets are described. The process for manufacturing the abrasive sheeting provides an economical method for providing improved quality abrasive sheeting, while also allowing for greater control over the shape and distribution of abrasive islands on the sheet than is available from present processes of manufacture.

1. Field of the Invention
The present invention relates to abrasive media and processes for manufacturing the abrasive media. The media are thin flexible abrasive sheeting used for lapping, polishing, it finishing or smoothing of workpiece surfaces. In particular, the present invention relates to such media used as removable or replaceable abrasive sheeting that are able to operate at high surface speeds, particularly media having an annular distribution of abrasive particles bonded in monolayers to the top surfaces of raised island shapes which are repeated in patterned arrays. Forming raised islands integrally attached to inexpensive backing sheets, precisely leveling the height of each island, resin coating the islands and applying abrasive particles to the resin economically creates an abrasive article which will grind a workpiece precisely flat and also generate a smooth workpiece surface. Coolant water freely passing through flow channels formed by the valley passageways between the raised islands flushes out grinding swarf and also minimizes hydroplaning of the workpiece.
2. Background of the Invention
High speed lapping and grinding using fixed abrasive on sheet disks for both rough grinding and smooth polishing is now a practical reality. Most performance issues relate to four primary concerns, 1) hydroplaning caused by water lubricant and 2) a free exit path for grinding debris swarf away from the contact area between the abrasive and the lapped article, 3) the utilization of all the abrasive particles attached to a sheet and 4) variations during abrading use created by thickness variations of abrasive disks along their tangential surfaces. Unique answers for all four problems of hydroplaning, debris path, use of particles and thickness variations have been defined and numerous solutions have been created.
This invention references commonly assigned U.S. Pat. Nos. 5,910,041; 5,967,882; 5,993,298; 6,048,254; 6,102,777; 6,120,352 and 6,149,506 and all contents of which are incorporated herein by reference.
The most serious problem remaining in the commercial use of high speed lapping and polishing processes is the availability of high quality abrasive article sheets that have certain important characteristics. The present invention describes sheets that can rapidly advance the use of high speed lapping by providing abrasive sheets that meet the needs of the technology. The sheets should be of a sufficient dimension (e.g., at least a 6 inch (15.3 cm) diameter, at least a 12 inch (30.5 cm) diameter, or at least an 18 inch (45.7 cm) or larger diameter, and have islands comprising abrasive particles (preferably secured to a substrate and preferably arranged in an annular band). The islands have an uppermost abrasive surface that is extremely flat and of uniform thickness. Conventional flat surface grinding or lapping platens are set up to use the full surface area of a circular shaped flat flexible sheet of abrasive. However, the abrasive contact surface speed of the rotating disk varies from a maximum speed at the outer radius to essentially mathematical zero at the innermost center at the disk (where the radius is zero). The grinding material removal rate is roughly proportional to the surface speed of the moving abrasive, so that most of the grinding or lapping action, and the most efficient grinding or lapping action occurs at the outer portion of a rotating disk. Not only is the inside portion of the abrasive disk not used to remove workpiece surface material, but also this portion of the abrasive is not worn down by the workpiece, resulting in a shallow, cone shape of the abrasive disk surface. This uneven wear continues with usage of the disk, with the cone angle progressively increasing to a sharper angle. This cone angle is translated to the surface of the workpiece that is intended for rigid axis lapping of a workpiece and prevents precision flatness grinding of the workpiece, transferring uneven surface contour to the workpiece surface. An effective answer to this uneven wear is to create an abrasive disk with a narrow annular band of abrasive material (at the outer edges of the annulus), allowing the abrasive to wear down more evenly across the full surface of the abrasive disk (which is essentially the annulus, not a continuous circular surface) as the disk is used. This type of media is not available commercially and probably would not be with present production methods. This is because the continuous method of manufacturing abrasive disks cannot technically or economically produce the necessary annular configuration.
Presently, an important method of manufacturing circular abrasive sheets is to coat a continuous web backing with diamond particles to form a coated sheet material and then to punch out round disks from the coated sheet material. Effectively, most of the expensive inner surface area of these disks is wasted. If a conventional coated disk is used with a platen having an outer raised annular ring, then all of the abrasive coated area located at a radius inside the ring is not used as it does not contact the workpiece surface.
Furthermore, it is not practical to punch out radial rings from a coated web sheet for a number of reasons. First, there is not necessarily a ready market for the smaller disk that remains left over from the center punch-out for the annular ring. Also, there is a large waste of coated web material left over between the circular disks that are cut out, even with proficient xe2x80x9cnestingxe2x80x9d of the circular rings. In addition, the extra flexible center-less annular abrasive ring not having backing on the inner radius when made of thin 0.005 inch (0.127 mm) thick polyester web has limited structural body strength for handling and mounting. The center-less ring cannot be practically used on a platen without creating many problems, including the problem that water and grinding swarf tend to collect under the inside radial edge of the loose annular ring sheet. Furthermore, round or bar raised-abrasive islands having a thin top coating of expensive diamond particles are needed to compensate for hydroplaning affects at high surface speed lapping. The only island type of abrasive media now available which can reduce hydroplaning is a diamond particle metal plated Flexible Diamond Products abrasive sheet supplied by the 3M Company (Minnesota Mining and Manufacturing Co.). However, due to the manufacturing process of this product, the product is commercially limited by at least two counts. First, each disk has large variations in flatness, or thickness, and, due to its unique construction, cannot be made flat enough to use effectively at high speeds where the unevenness is accentuated by the speed. Second, the Flexible Diamond Product abrasive sheet is constructed from plated diamonds, which have been unable to produce a smooth polished finish.
Another widely used product from 3M Company is the pyramid shaped Trizact abrasive, which helps with hydroplaning effects. However, it is only practical for this product to be created with inexpensive abrasive media such as aluminum oxide, which tends to wear fast and unevenly across its surface. Again, this is a continuous web type of product, which does to have the capability of having or maintaining precise abrasive thickness control.
Two common types of abrasive articles that have been utilized in polishing operations include bonded abrasives and coated abrasives. Bonded abrasives are formed by bonding abrasive particles together, typically by a molding process, to form a rigid abrasive article. Coated abrasives have a plurality of abrasive particles bonded to a backing by means of one or more binders Coated abrasives utilized in polishing processes are typically in the form of endless belts, tapes, or rolls which are provided in the form of a cassette. Examples of commercially available polishing products include xe2x80x9cIMPERIALxe2x80x9d Microfinishing Film (hereinafter IMFF) and xe2x80x9cIMPERIALxe2x80x9d Diamond Lapping Film (hereinafter IDLF), both of which are commercially available from Minnesota Mining and Manufacturing Company, St. Paul, Minn.
Structured abrasive articles have been developed for common abrasive applications. U.S. Pat. No. 5,152,917 (Pieper, et al.) discloses a structured abrasive article containing precisely shaped abrasive composites. These abrasive composites comprise a plurality of abrasive grains and a binder. U.S. Pat. No. 5,107,626 (Mucci) discloses a method of introducing a pattern into a surface of a workpiece using a structured abrasive article.
A new class of large diameter precise thickness disks that have an annular ring of raised islands coated with a thin coat of diamond abrasive particles is required for high speed lapping which requires a completely different manufacturing technique than has been employed in the past by the abrasives industry. The new batch type of processing required to produce these disks must be practical and cost effective. Eventually, this batch process of manufacturing a disk as a separate item should be converted partially or wholly into a continuous process when product sales volume demand warrants the investment in process equipment and converting technology.
The primary competitor for the sheet fixed abrasive polishing technology is slurry lapping, which is necessarily very slow, even though it has been progressively up-dated. Slurry lapping produces a flatter surface on a workpiece at the present time than can be accomplished by high speed lapping, which has limited the sale of the high-speed lapper machines. Other traditional grinding wheel machines can produce about the same flatness accuracy as the present configuration lapper but can not produce the associated smooth polish that typical workpiece parts require. Accurate flat and smooth surfaces are used on work piece component parts to prevent lubricating or other pressurized fluid leakage at the contact surface where these parts are mated stationary with other parts or where these parts are joined to dynamically rotate against each other.
High speed lapping uses expensive thin flexible abrasive coated disks that must be very precise in thickness and must also be attached to a platen that is very flat and stable. As the platen rotates very fast, this speed tends to xe2x80x9clevelxe2x80x9d the abrasive as it is presented to the workpiece surface. At high speeds only the high spots of the abrasive contact the workpiece, the remainder of the disk abrasive is not used until the high spots wear down. Thus, it is necessary for the total system to be precisely aligned and constructed of precision components to initialize the grinding. Furthermore, the wear of the abrasive must proceed uniformly across both the surface of the sheet and the surface of each island to maintain the required flatness of both the effective abrasive surface and correspondingly, the workpiece surface. These issues have all been addressed in the latest configuration of a lapper machine along with the process techniques employed in operating it. To generate even wear with rotating abrasive disks, an annular raised abrasive is used as taught in U.S. Pat. Nos. 5,910,041; 5,967,882; 5,993,298; 6,048,254; 6,102,777; 6,120,352 and 6,149,506. However, the desired large disks are not available, as the size of commercially available abrasive disks is presently limited to about 12 inches (30.48 cm) diameter. This severely limits the width of the annular ring without the resultant much slower surface grinding speed at the inside diameter of the ring. This slower speed also results in reduced material removal from the portion of the workpiece at this inside radial location. Furthermore, as the inside radial section of the abrasive disk wears slowly, the outside diameter portion progressively wears down faster which results in an uneven surface on the annular ring. Having larger nominal diameter abrasive disks with fairly narrow annular bands will inherently take care of most of these problems.
The typical workpieces that are lapped initially are not flat and have rough surfaces. Most potential customers seem to want both very flat (within 2 light bands) and smooth polished surfaces.
A preferred abrasive flat lapping process is now done in two separate steps. First, the parts are ground flat using a rigid spindle running at full 3,000 RPM speed, a very small contact force of 1 to 2 lbs. (0.454 to 0.908 kg) and typically, 3M""s 12 inch (305 mm) diameter metal plated diamond abrasive. Water flows between the round islands of abrasive, reducing hydroplaning. Hydroplaning typically produces a cone shaped ground surface. Second, parts are polished using a spherical action workpiece holder, with low to moderate contact forces of 2 to 15 lbs. (0.908 to 6.81 kg), and uses a smooth coated abrasive disk operating at lower speeds of about 1,000 RPM or less to prevent hydroplaning. At this time, no xe2x80x9cisland typexe2x80x9d of coated abrasive is available for polishing in combination with an effective polishing method.
Generally, use of the metal plated diamond island style abrasive disks to remove material is considered to be xe2x80x9cgrinding,xe2x80x9d as the surface finish is not smooth to the high standards of polishing. Use of the coated abrasives creates very smooth surfaces and is considered to be xe2x80x9clappingxe2x80x9d. The plated diamond disks tend to be very durable and may last a long time during use. The coated diamond and other abrasive particle disks are much more fragile and are consumed much more rapidly.
With respect to performance, with rigid flat grinding, 2 light bands of flatness are obtained which is not sufficiently flat for many applications. Polishing results in acceptable smoothness, but typically creates new problems with flatness because of hydroplaning. Flatness defects created in the polishing step include both cone shapes and saddle shapes.
It is important that super abrasives such as diamond (or other materials having minimal mohs hardness values within at least 20%, or at least 10% of the hardness of diamonds) be used at a minimum surface speed of 5,000 SFPM (surface feet per minute) or 1,524 meter per minute to achieve fast material removal.
The high surface speed of the plated abrasive island articles creates extraordinary high rates of material removal of very hard materials and this perhaps can be increased even further with higher speeds. This is the primary reason for the interest of the high speed grinding and lapping.
Hydroplaning of parts using fine small particle coated abrasive will always be a problem at very high speeds until an abrasive article disk is available which has xe2x80x9cislandsxe2x80x9d of abrasive which allows excess water to pass around the island edges. A recent new commercial form of abrasive disks that has the abrasive formed into small pyramids of abrasive is available and it initially works well from a hydroplaning standpoint when the pyramids are fresh and not too worn down. However, this Trizact(copyright) brand disk sold by 3M is created only with relatively soft aluminum oxide and tends to wear out fast. It is not logical that the manufacturer would use longer wearing diamond particles in these pyramid shapes, as each disk would consume so much diamond that the costs would be too high.
A number of inventions are beginning to be considered to address the desirability of using, abrasive islands to achieve acceptable lapper workpiece flatness but they have fundamental problems. In one example, island-like foundations, which are constructed of large diameter agglomerates comprising both abrasive particles and erodible filler materials, are used, but these large agglomerates tend to wear away at the abrasive article surface unevenly. In another example, abrasive articles with patterns of shallow sinusoidal shaped rounded island-like foundation ridge shapes, the ridges formed of filler materials, with abrasive particles coated conformally to both the peaks and valleys alike is described: the shallow ridge valleys are not necessarily oriented to provide radial direction water conduits on a circular disk for flushing grinding debris away from the work piece surface even prior to wear down of the ridges; and a substantial portion of the abrasive particles residing on the ridge valley floors remain unused as it is not practical to wear away the full height of the rounded erodible ridges to contact these lower elevation particles.
The preferred shape of a raised island abrasive article is rotational round disk with an outer annular ring of raised abrasive islands which can be manufactured in batches but the same raised island flexible backing material can be manufactured in continuous web form to create a linear article such as a rectangular sheet or a endless belt.
U.S. Pat. No. 5,611,825 (Engen) describes resin adhesive binder systems which can be used for bonding abrasive particles to web backing material, particularly urea-aldehyde binders. There is no reference made to forming or abrasive coating abrasive islands. He describes the use of make, size and super size coatings, different backing materials, the use of methyl ethyl keytone and other solvents. Loose abrasive particles are either adhered to uncured make coat binders which have been coated on a backing or abrasive particles are dispersed in a 70 percent solids resin binder and this abrasive composite is bonded to the backing. Backing materials include very flat and smooth polyester film for common use in fine grade abrasives which allow all the particles to be in one plane. Primer coatings are used on the smooth backing films to increase adhesion
U.S. Pat. No. 5,820,450 (Calhoun) and U.S. Pat. No. 5,437,754 (Calhoun) discloses the use of individual spaced truncated cones and rectangular agglomerate blocks attached to 50 micrometer (0.00196 inch) thick polyethylene terephthalate (PET) with an 18 micrometer (0.0007 inch) thick ethylene acrylic acid copolymer (EAA) surface primer coating using toluene to solvent viscosity-thin a abrasive slurry binder where the agglomerates are spaced with gaps on the backing by use of a embossed carrier web having spaced receptacles filled with the abrasive slurry mixture. U.S. Pat. No. 6,228,133 (Thurber, et al.) describes the application of silane coupling agent to abrasive particles which increases the adhesion of the particle to the binder and priming the backing surface for increased adhesion of the binder by corona discharge, ultraviolet light exposure, electron beam exposure, flame discharge and scuffing; abrasive particles are applied by electrostatic coating.
U.S. Pat. No. 4,311,489 (Kressner) discloses the use of irregular surface agglomerates of abrasive particles and a binder where the agglomerate binder is weaker than the agglomerate make coat binder to permit gradual wearing down of the agglomerate.
U.S. Pat. No. 5,219,462 (Bruxvoort, et al.) discloses the use of dot patterned recesses or through-holes in a backing sheet which are filled with a slurry of fine abrasive particles having an expanding agent which expands the slurry to rise above each recessed hole. The passageways between the raised abrasive composite dots can pass water and slurry until the dots arc worn down. A disadvantage with this type of abrasive article is that all of the abrasive particles contained in the recess hole at a location below the exposed surface of the backing sheet is lost for abrading use. The importance of the control of height of the top of the dot is recognized in the disclosure in that a flat mold surface can be pressed against the non-hardened abrasive dots but no description is presented concerning the importance and accuracy of controlling the dot heights.
U.S. Pat. No. 794,495 (Gorton) discloses dots of abrasive on round disks formed by depositing abrasive particles on adhesive binder wetted dot areas printed on the backing, primarily to aid the free passage of grinding debris away from the workpiece surface. These dot areas are not elevated as raised island shapes from the surface of the backing.
U.S. Pat. No. 1,657,784 (Bergstrom) discloses a variety of abrasive particle primitive shaped areas with space gaps between the abrasive areas to provide a passageway for grinding swarf.
U.S. Pat. No. 3,246,430 (Hurst), U.S. Pat. No. 2,838,890 (McIntyre) and U.S. Pat. No. 2,907,146 (Dyar) disclose the effect of an uneven abrasive surface on a workpiece article and various techniques to create separated areas of abrasives.
U.S. Pat. No. 5,549,961 (Haas, et al.) discloses abrasive particle composite agglomerates in the shape of pyramids, truncated pyramids, and beads which are mixed in a slurry having ultrasonic energy used to lower the slurry viscosity and vacuum to minimize air bubbles. Abrasive composites are forced with abrasive article surface densities of 700 to 7,500 mold cavities per square centimeter. A typical truncated pyramid has a height of 3.15 mils (80 micrometer), a base of 7.0 mils (178 micrometer) and a top of 2 mils (51 micrometer) and is continuously abutted with adjacent pyramids to form a flat continuous sheet of abrasive. When a xe2x80x9cdaisyxe2x80x9d form shape is cut out from a sheet, the daisy is flooded with water or water with additives including water soluble oils, emulsified oils, wetting agents which suggest low speed operation. Clay additives were used to improve the control of erodibility of the abrasive composite. Surface coatings including halide salts, metal oxides and silica were applied to the abrasive particles to increase adhesion.
U.S. Pat. No. 6,231,629 (Christianson, et al.) discloses a slurry of abrasive particles mixed in a binder to form truncated pyramids and rounded dome shapes on a backing. Fluids including water, an organic lubricant, a detergent, a coolant or combinations thereof results in a finer finish on glass. Fluid flow in valleys between the pyramid tops tends to produce a better cut rate and increased flatness during glass polishing. Abrasive diamond particles either have a blocky shape or a needle like shape and may contain a surface coating of nickel, aluminum, copper, silica or an organic coating.
U.S. Pat. Nos. 6,080,215 (Stubbs, et al.) and 6,277,160 (Stubbs, et al.) discloses side-by-side coatings of different size abrasive particles by use of abrasive coating slurries where the abrasive particles are surface coated with materials including coupling agents, halide salts, metal oxides including silica, refractory metal nitrides and carbides. Fillers including amorphous silica and silica clay are used in abrasive slurries which contain methyl ethyl keytone, MEK, and toluene, TOL in various mixture ratios. Drying patterns which can be seen visually and are referred to as Bernard cells alter the nature of the abrasive coating and their existence depends on airflow and heating conditions during thermal cure of the slurry binder. Polishing liquids used include lubricants, oils, emulsified organic compounds, cutting fluids and soaps.
U.S. Pat. No. 6,217,413 (Christianson) discloses use of phenolic or other resins where abrasive agglomerates are drop coated preferably into a monolayer of abrasive agglomerates and leveling and truing which levels or evens out the abrading surface is performed on the abrasive article resulting in tighter tolerance during abrading.
U.S. Pat. No. 5,910,471 (Christianson, et al.) discloses that the valleys between the raised adjacent abrasive composite truncated pyramids provide a means to allow fluid medium to flow freely between the abrasive composites contributes to better cut rates and increased flatness of the abraded workpiece surface.
U.S. Pat. No. 5,232,470 (Wiand) discloses raised molded protrusions of circular shapes composed of abrasive particles mixed in a thermoplastic binder attached to a circular sheet of backing.
U.S. Pat. No. 4,930,266 (Calhoun, et al.) discloses the application of spherical abrasive composite agglomerates made up of fine abrasive particles in a binder in controlled dot patterns where preferably one abrasive agglomerate is deposited per target dot by use of a commercially available printing plate. Small dots of silicone rubber are created by exposing light through a half-tone screen to a photosensitive silicone rubber material coated on an aluminum sheet and the unexposed rubber is brushed off leaving small islands of silicone rubber on the aluminum. The printing plate is moved through a mechanical vibrated fluidized bed of abrasive agglomerates which are attracted to and weakly bound to the silicone rubber islands only. The plate is brought into nip-roll pressure contact with a web backing which is uniformly coated by a binder resin which was softened into a tacky state by heat thereby transferring each abrasive agglomerate particle to the web backing. Additional heat is applied to melt the binder adhesive forming a meniscus around each particle, which increases the bond strength between the particle and the backing. The resulting abrasive has dots of abrasive particles on the backing but they are only raised away from the backing surface by the diameter of the abrasive agglomerates. Each abrasive agglomerate typically ranges in size from 25 to 100 micrometers and contains 4 micrometer abrasive particles.
U.S. Pat. No. 3,916,584 (Howard, et al.) and U.S. Pat. No. 4,112,631 (Howard) discloses the encapsulation of 15 micrometer and smaller diamond and other abrasive particles in spherical erodible composites as he discloses that large particles can be coated on abrasive articles or used in slurries without the need for encapsulation.
U.S. Pat. No. 6,186,866 (Gagliardi) discloses the use of protrusions having a variety of peak-and-valley shapes comprised of an erodible grinding aid where the protrusion shapes are surface coated with an adhesive resin and abrasive particles are drop coated or electrostatically coated onto the resin forming a layer of abrasive particles conformably coated over both the peaks and valleys. There are apparent disadvantages of this product. Only a very few abrasive particles reside on the upper most portions of the protrusion shaped peaks and this small fraction of the total number of particles coated on the surface will quickly be worn down or knocked off the peaks by abrading action due to their inherently weak resin support at the curved peak apex. As the abrading action continues with the wearing down of the erodible protrusions, more abrasive particles are available for abrading contact with a workpiece article but the advantage of the valleys used to channel coolant fluids and swarf has now diminished. The abrasive particles are very weakly attached to the sloping sidewalls of the protrusions due to the simple geometric vulnerability of bonding a separate particle to a protrusion wall side. Adhesive binder that does not naturally flow and surround the particle to generate substantial strength to resist abrading contact forces which will tend to leverage the particle and break it away from the wall. Much of the valuable superabrasive particles located in the valley areas are not utilized with this technique of particle surface conformal coating of peaks and valleys.
U.S. Pat. No. 5,190,568 (Tselesin) discloses a variety of sinusoidal and other shaped peak and valley shaped carriers that are surface coated with diamond particles to provide a passageway for the removal of grinding debris. The problems inherent with this technique include the change in localized grinding pressure, in newtons per square centimeter, when a work piece first contacts only a few abrasive particles located at the top of the peaks as compared to a greatly reduced pressure when the peaks are worn down and substantially more abrasive particle surface area is in contact with the workpiece. The inherent bonding weakness of abrasive particles attached to the sloping sidewalls is discussed and the intention for some of the lower abrasive particles located away from the peaks being used to structurally support the naturally weakly bonded upper particles. The material used to form the peaks is weaker or more erodible than the abrasive particles, which allows the erodible peaks to wear down, expose, and bring the work piece into contact with new abrasive particles. Uneven wear-down of the abrasive article will reduce its capability to produce precise flat surfaces on the work piece. Abrasive articles with these patters of shallow sinusoidal shaped rounded island-like foundation ridge shapes where the ridges are formed of filler materials, with abrasive particles coated conformably to both the ridge peaks and valleys alike is described. However, the shallow ridge valleys are not necessarily oriented to provide radial direction water conduits for flushing grinding debris away from the work piece surface on a circular disk article even prior to wear down of the ridges. Also, a substantial portion of the abrasive particles residing on the ridge valley floors remain unused as it is not practical to wear away the full height of the rounded ridges to contact these lower elevation particles.
U.S. Pat. No. 5,496,386 (Broberg, et al.) discloses the coating of a mixture of diluent particles and shaped abrasive particles on a make coat of resin where the function of the diluent particles is to provide structural support for the shaped abrasive particles.
U.S. Pat. Nos. 4,256,467 (Gorsuch) and 5,318,604 (Gorsuch. et al.) discloses abrasive articles where the coating of fibrous cloth at island areas built up in raised height by electroplating areas of the cloth positioned in contact with electrically insulated metal having arrays of exposed circular electrically conducting island forming areas. Abrasive particles contained in the electroplating bath are introduced to fall on the upper portion of the plated metal islands during the process of attaching them to the fiber islands. However, the particles do not lie in a common plane at a flat surface of the raised islands. Instead, the particles are attached at many different elevations within the island areas. This out of flatness occurs because the individual fibers of the cloth which support the build-up of plated metal to create raised island structures is not flat at the upper surface of the progressively built-up plated island due to the fibers being woven together to form the cloth material. The different height locations of the particles prevent the generation of precision smooth surfaces during the abrading action but the abrasive island articles are effective in producing flat work pieces. Another disadvantage of this product is that the plated cloth material must be stripped from the electrically conductive metal base and attached as a laminate with adhesive to a backing substrate to form an abrasive article. This laminated abrasive article structure does not have the precise thickness control due to thickness variations in both the island plated cloth material and the laminating adhesive film for effective utilization of the diamond abrasive particles for high speed lapping.
Lapper Process and Apparatus
Lapping or grinding with abrasives fixed to a flexible sheet is performed at high surface speeds of 3,000, 5,000 or 10,000 or more surface feet per minute (913, 1524, or 3,048 meters per minute), requiring the use of water-like lubricants to cool the workpiece and to carry away grinding swarf. A workpiece can be held rigidly or flexibly by a rotating spindle platen to effect grinding contact with a rotating abrasive platen, but the platen must be maintained precisely perpendicular to the abrasive surface to obtain a workpiece surface flat within about 2 lightbands. The aggressive cutting action of plated diamond island style flexible sheets requires the grinding contact perpendicular force to be near zero pounds at the start and end of the grinding procedure and to be controlled within plus or minus 0.5 pounds (227 grams) with a typical nominal force of 2.0 lbs. (0.908 kg) for an annular ring shaped workpiece having approximately 3.0 square inches (58.1 square cm) of surface area. Hydroplaning of the workpiece on the water lubricated abrasive is minimized when using abrasive covered raised island sheets, but is severe for uniformly coated abrasive disks generally used for smooth polishing or lapping. Hydroplaning causes cone shaped ground workpiece surfaces, even with raised platen annular rings. The abrasive platen must be ground very flat and the abrasive disk sheet must be precise in thickness to be used effectively at high speeds.
Abrasive disks of large 18 inch (0.457 m), 24 inch (0.609 m), 36 inch (0.914), 48 inch (1.22 m) or even 60 inch (2.3 m) diameter having an outer annular band of raised islands which have a thin precise coating of diamond particles can be produced effectively with very precise thickness control. Raised island foundation bases can be deposited on a backing by a variety of means on a variety of commonly available thin flexible plastic or metal backing materials. These island foundation base plateau surfaces are machined or ground after attachment to the backing to establish a precisely controlled thickness relative to the bottom surface of the disk backing material. It is not critical that the thickness of the backing be accurately controlled as with traditional precision backing for lapping abrasive articles as the islands are machined to a uniform height after they are deposited on the backing. Loose diamonds or other abrasive particles, including composite structured agglomerates, can be metal plated or organic resin binder coated as a single mono layer on top of the top flat surface of the islands. Abrasive particles can be attached to or drop coated or electrostatic coated onto a wet organic resin island surface coating. Abrasive particle slurry binders can be coated onto the island surfaces. Resin coatings are based on organic resins including phenolics and epoxies which have been used traditionally in the abrasive industry for many years. A make binder resin coating (is a batch coating for applying resin) can be applied to an island foundation top surface, abrasive particle powder applied, a partial or full resin cure effected, a resin size coat applied and then a full resin cure effected by heat or other energy sources. These disks principally would be produced by a batch process, but a more traditional continuous web process can also employ the same basic process technology of creating abrasive particle coated raised islands in array patterns where this abrasive web material can be converted to form annular disks or rectangular sheets or continuous belts or other abrasive articles such as daisy wheels. A wide range of abrasive articles can be produced with fine abrasive particle disk sheets or belts can be used for lapping and coarse particle disks can be used for grinding. All the abrasive articles can be used at high surface speeds, which fully utilize the increased abrading material removal rates which occur at high speeds, particularly with diamond particles.
A number of techniques are described to establish a uniform thickness of a make coat of binder to the top surface of island foundations which have been previously ground to a very precise height as measured from the bottom side of a backing material. One method to produce this make coat is to first spin coat a layer of binder resin onto a flexible sheet of backing and then to press this binder wetted coating onto the top surface of an annular array of raised islands attached to a round backing. Approximately one half (e.g., between 20% and 75%, or more) of the spin-coated binder is transfer coated to the island top surfaces when the spin-coated transfer sheet is separated from the island sheet. Abrasive particles can be drop coated onto the binder-wetted surface of the islands and then the binder can be partially or fully cured. Make coats of resin may be wet through the full thickness of the resin coat or only the surface of a partially cured resin may be given a wet surface condition by the application of heat or by other means prior to the application of abrasive particles. Subsequently, other size coats of binders can be applied to the island sheet, optionally coating either the island tops only, or covering both the island tops and the island valleys. Make coatings can be applied optionally by various printing techniques directly on the surface of the island both for the make coat, the size coat and other coatings. A variety of techniques are described which control the application of the abrasive particles to achieve a uniform density of particles on the surface of the islands where there is no more than 65 percent of a given island area surface covered by abrasive particles. Further, the resultant layer of particles is controlled to minimize the occurrence of more than a single (mono) layer of particles on an island surface. The resultant sheet or disk form of abrasive article has a single layer of abrasive particles bonded to island surfaces where the variation of height (measured from the backside of the abrasive particle backing) of adjacent particles on islands is typically less than one half the average diameter of the particle. One objective in the use of a single layer of abrasive particles is to utilize a high fraction of the expensive particles particularly the two superabrasives diamond and cubic boron nitride (CBN). Another objective is to minimize the dimensional change in the flatness of the abrasive article due to wear-down. A preferred abrasive particle size is 30 microns (micrometers) which is slightly more than 0.001 inch (25.4 microns). When the abrasive is fully worn away, the abrasive surface of the islands has therefore only changed by approximately 0.001 inch or 25.4 microns which is a very small change in height or flatness compared to other lapping abrasive articles in common commercial use at the present. A number of the present commercial articles are coated with fused spheres, pyramids and other agglomerate shapes which have nominal effective diameters of two to ten times or more, of the basic abrasive particles contained in the erodible agglomerate carrier shapes. These large agglomerates tend to wear unevenly from the contact with workpiece articles due both to the contact size of the workpiece typically being smaller than the abrasive article surface, and also, due to the increased wear-down at the outer diameter of an circular abrasive disk article and decreased wear-down at the slower surface speed movement at the inside diameter. When the agglomerate wears down unevenly on a portion of its surface, this uneven abrasive surface is now an presented to a new (sequential operation) work piece article which reduces the capability of the lapping process to quickly and economically effect the creation of a flat surface on the workpiece. The workpiece may be smoothly polished due to the characteristics of the fine abrasive particles imbedded in the erodible agglomerates, but the workpiece surface will tend not to be flat.
It is preferred that a single or monolayer of individual abrasive particles, such as natural or man-made diamond particles, be coated on abrasive island tops but a single or mono layer of erodible agglomerates made up of smaller abrasive particles can be used on top of the abrasive islands. In this work, each of the island foundations are high enough from the surface of the abrasive article backing that cooling water and generated grinding swarf can freely travel down the valleys between the island tops. The radial flow of water and debris swarf is created by the centrifugal forces generated by rotation of the abrasive sheet so the spent water exits the active grinding surface area of the disk while fresh clean water is supplied continuously over the whole time of the grinding event.

Raised island abrasive and process of manufacture


A method of and apparatus for migrating data between storage devices for reducing power consumption. Unlike prior techniques for conserving power by spinning down a magnetic disk (e.g., in a laptop computer), the present invention migrates data based on the assumption that the disk is maintained spinning (e.g., in a server). Accordingly, the incremental power consumed by maintaining data on the disk is nominal in comparison to the amount of power required to store the data in volatile memory (e.g., RAM). Data placement is largely based on the goal of minimizing power consumption during periods when the data is not being accessed. Further, unlike conventional techniques in which data is removed from RAM only when a better candidate is available to replace the data, the present invention may move data from RAM regardless of whether replacement data is available. This is avoids consumption of power to maintain data in RAM that is idle. Thus, under certain conditions, the inventive technique for data migration in a computer system reduces power consumption in comparison to conventional algorithms.

The present invention relates to the field of data storage for computer systems. More particularly, the present invention relates to the field of migrating data between storage devices in a computer system so as to conserve resources, such as power.
Computer systems typically include both random access memory (RAM) and magnetic disk memory. Each of these memory devices has its advantages and disadvantages. For example, RAM is generally more expensive than disk memory, but also has lower read and write latencies.
Conventional methods for moving data between RAM and disk memory devices in a computer system take into account some these relative strengths. More particularly, a conventional method moves blocks of data between RAM and disk memory based solely on a single parameter, a re-use xe2x80x9cvalue,xe2x80x9d for each block of data. Typically, the reuse value for a particular block of data is computed based on historical use of the block; those blocks that require more frequent access have higher reuse values. The reuse value for each block is compared to that of other data blocks. Those blocks that require more frequent access are placed in RAM while the remaining blocks are stored in disk memory. When the reuse value for a block in disk memory exceeds that of a block in RAM, the block from disk memory replaces the block in RAM. This method, however, does not take power consumption into consideration. Nor does this technique take into account the amount of time an unused block remains in RAM; rather, unused blocks remain in RAM based solely on how quickly an alternative block is available to replace it.
For battery-powered systems, such as laptop computers, it is generally desired to minimize power consumption so as to maximize usage between battery recharges. A feature of magnetic disk storage that is conventionally exploited in battery-powered systems is placement of the disk into standby mode to reduce power consumption. Typically, a disk in standby mode is xe2x80x9cspun-downxe2x80x9d to conserve power which would otherwise be used to keep the disk spinning. When the disk needs to be read from or written to, it is necessary to then xe2x80x9cspin-upxe2x80x9d the disk. In order to amortize the amount of power required to spin-up the disk, the disk must have been maintained in the standby mode for at least a certain amount of time. In their paper entitled, xe2x80x9cAdaptive Disk Spin-down Policies for Mobile Computers,xe2x80x9d Second USENIX Symposium on Mobile and Location-Independent Computing, Ann Arbor, Mich. pp. 121-137 (April 1995), F. Douglis, P. Krishnan and B. Bershad describe a system in which algorithms attempt to maintain the disk in standby mode as much as possible while minimizing the frequency of spinning up the disk. This power-saving technique is limited, however, by the ability to amortize the power required to spin-up the disk.
In their paper entitled, xe2x80x9cEnergy-aware adaptation for mobile applications,xe2x80x9d ACM 1-58113-140-2/99/0012 (1999), J. Flinn and M. Satyanarayanan, discuss the use of application software that can dynamically modify its behavior to conserve energy in a mobile computer. This technique has a drawback in that power savings are generally achieved at the cost of fidelity, such as in display of graphics.
Another technique for conserving power in mobile computers involves the use of power management features of certain DRAM devices. In their paper entitled, xe2x80x9cPower Aware Page Allocation,xe2x80x9d Proceedings of the Ninth International Conference in Architectural Support for Programming Languages and Operating Systems (November 2000), A. Lebeck, X. Fan, H. Zeng and C. Ellis consider page allocation policies to complement the ability of the memory devices to adjust power modes. This technique has a drawback in that it requires specially-designed DRAM devices.
Yet another paper, xe2x80x9cStorage Alternatives for Mobile Computers,xe2x80x9d F. Douglis, R. Cxc3xa1ceres, F. Kaashoek, K. Li, B. Marsh and J. Tauber, Proceedings of the 1st USENIX Symposium on Operating Systems Design and Implementation, (OSDI ""94) Monterey, Calif., pages 25-37 (November 1994), discusses data storage for mobile computers. The authors investigate use of magnetic hard disks, flash memory disk emulators and flash memory cards for mobile computers. Flash memory is considered for replacing or augmenting disk memory, but no policies are suggested that would conserve power during periods in which data is idle.
Therefore, what is needed is a technique for migrating data between storage devices that does not suffer from the aforementioned drawbacks. More particularly, what is needed is such a technique in which power consumption is minimized. It is to these ends that the present invention is directed.
The invention is a technique for migrating data between storage devices for reducing power consumption. Unlike prior techniques for conserving power by spinning down a magnetic disk, the present invention migrates data based on the assumption that the disk is maintained spinning (e.g., in a server). Accordingly, the incremental power consumed by maintaining data on the disk is nominal in comparison to the amount of power required to store the data in volatile memory (e.g., RAM). Data placement is largely based on the goal of minimizing power consumption during periods when the data is not being accessed. Further, unlike conventional techniques in which data is removed from RAM only when a better candidate is available to replace the data, the present invention may move data from RAM regardless of whether replacement data is available. This is avoids consumption of power to maintain data in RAM that is idle. Thus, under certain conditions, the inventive technique for data migration in a computer system reduces power consumption in comparison to conventional algorithms.
In accordance with an aspect of the invention, data is migrated between storage devices in a computer system having a first memory device and a second memory device. The first memory device may require more power to maintain a data block valid than the second memory device. The data block is moved from the first memory device to the second memory device when an anticipated amount of time before a next access to the data block exceeds a predetermined threshold.
The data may be moved from the first memory device regardless of whether a replacement data block is available. The first memory device may include random access memory (RAM) while the second memory device may include a magnetic disk or flash memory. The magnetic disk may be maintained in its spinning condition. The first memory device may require repeated refreshing while the second memory device may not.
In accordance with another aspect of the invention, the first memory device, the second memory device and a third memory device are included in the computer system. A data block is moved from the first memory device to the second memory device in response to an anticipated time until a next access to the data block for reading or writing. Alternately, the data block is moved from the first memory device to the third memory device in response to an anticipated time until a next read access to the data block being different from an anticipated time until a next write access to the data block.
More particularly, the data block may be moved from the first memory device to the second memory device when the anticipated amount of time before a next read access to the data block exceeds a first predetermined threshold and an anticipated amount of time before the next write access to the data block exceeds a second predetermined threshold. Further, the data block may be moved from the first memory device to the third memory device when the anticipated amount of time before the next read access to the data block does not exceed the first predetermined threshold and the anticipated amount of time before the next write operation exceeds the second predetermined threshold.
The third memory device may include flash memory. Thus, the third memory device may have a write latency that is significantly higher than its read latency.
In accordance with yet another aspect of the invention, a data block is assigned to the first memory device of the computer system. An anticipated amount of time before a next write access to the data block is computed. The data block is removed from the first memory device when the anticipated amount of time until the next write access to the data block exceeds a first threshold. An anticipated amount of time before a next read access to the data block is computed. The data block is inserted into the second memory device when the anticipated time until the next read access to the data block exceeds a second threshold. Otherwise, the data block is inserted into the third memory device.

Technique for migrating data between storage devices for reduced power consumption

Hewlett-Packard Development Company, L.P.


A digital imaging system uses a high density, high speed analog/multi-level memory to temporarily store image data at high rates for extended periods of time. A portion of the stored data is transmitted for image processing and compression. When image processing and compression on the data are completed, another portion of the stored data is transmitted for processing. As a result, high speed image capture for extended periods is possible because the processing speed of the image processing and compression no longer limit the time required between high speed bursts or the length of a high speed burst.

1. Field of the Invention
This invention relates to digital image signal processing and, in particular, to digital imaging structures and processes using an analog buffer memory.
2. Description of Related Art
Digital image processing can be used to convert an optical image to electronic image data, which is then converted to digital data for display or storage on a recording medium, such as a memory card. The stored digital data can later be retrieved to reproduce the image on a display device, such as a computer monitor, or on a hard copy medium, such as a color printer or photographic film.
FIG. 1 is a block diagram of a digital image processing system, in particular, a digital still camera (DSC) 100. DSC 100 includes an image sensor 110, such as a CMOS sensor or a charge-coupled device (CCD), pre-processing circuitry 115, an analog-to-digital (A/D) converter 120, an image processor and compressor 130, a digital memory device 140, read and interface circuitry 150, a liquid crystal display (LCD) 155, and external digital displays, such as a color LCD (not shown) or an external digital memory card 160. Generally, the image of an object is electrically processed by image sensor 110, which converts reflected light from the object into electrical signals, such as voltages.
The analog-to-digital (A/D) converter 120 then samples the analog signal and converts the signal into digital data. Some advantages of digitized information include processing flexibility and higher signal to noise ratio during transmission to reduce error rates and improve picture quality. However, digital data can require very large memory storage capacities and transmission bandwidths.
For example, typical VGA images have a spatial resolution of approximately 307K pixels/frame (i.e., 480 rows with 640 samples or pixels per row). In a digital image, the image is captured, processed, stored, and transmitted as an array of numerical values. The image is divided up into squares in a grid, with each square in the grid referred to as a pixel or sample. The intensity of the image at each pixel is translated into a numerical value which is stored in the array. If the pixel has one of the primary colors (i.e., R, G, B) to be sampled with 8 bits resolution, then there are approximately 2.5 Mbits of data per frame (307K*8), which requires approximately 307 Kbytes of memory storage capacity to store the sampled image. Furthermore, if a digital still camera (DSC) is required to capture 1 frame/sec, a data transmission rate or bandwidth of approximately 2.5 Mbits/sec is needed for a color image. Depending on the number of pixels per frame and the image processing and compression circuits, the memory storage and bandwidth requirements can be much higher than 307 Kbytes and 2.5 Mbits/sec, respectively.
In particular, it may be desirable for digital still cameras to capture images at a high rate, i.e., in "burst mode", for situations where frames are shot in rapid succession, such as during sporting events. For example, if a burst mode requires that 5 frames/sec be captured for high quality images of 2.0 Mbits/frame, then a minimum transmission rate or bandwidth of approximately 80 Mbits/sec or 80 MHz is needed. Further, if this burst mode is sustained for 5 seconds, then the storage capacity of the memory would need to be approximately 400 Mbits. Such large memories and bandwidths are either impractical or may require high capacity memory devices and very high speed circuit elements with parallel processing which can make the digital processing system complicated and very costly. Such a system can also require large amounts of power and board space.
Thus, the large memory storage and channel capacity requirements for digital image transmission and storage make it desirable to reduce the amount of digital data from A/D converter 120. By reducing the amount of data, the transmission bandwidth and/or the memory storage requirements are reduced. A well-known technique is to utilize image processing and compression circuits 130 to reduce the amount of digital data while storing enough data in memory to maintain a desired quality or resolution of the image. Image processing and compression circuits 130 can use common techniques, such as JPEG or run-length coding, to take advantage of the fact that certain pixel values tend to be highly redundant, such as with neighboring individual pixels or neighboring frames. Image processing and compression techniques, e.g., having compression ratios ranging from 4:1 to 20:1, can significantly reduce the number of bits required to represent images by removing these redundancies while still maintaining an acceptable quality of the reconstructed image.
After image processing and compression, the reduced digital data can be stored in a digital memory device 140, such as a memory card having a Flash EEPROM. Read and interface circuits 150 then access the desired image data from the memory device 140 and transmit the data to desired digital destinations, such as an LCD display 155, an external memory card 160, or a hard disk drive (HDD) in a PC (not shown). For example, with a digital still camera, elements 110 to 155 are typically embedded within the body of the digital camera so that digital memory 160 can be a memory card which is removable from the camera and available for subsequent processing of the stored image data. Data in the removed memory card can also be downloaded to a PC HDD or a kiosk for printing, used for later retrieval, or transmission through the Internet.
Thus, with image compression, smaller memories and lower transmission rates are possible. However, image processing and compression also require substantial amounts of time for performing complex and lengthy computations, which can adversely increase the minimum time delay between successive picture frames and/or burst rates. A high burst rate, which allows pictures to be taken in rapid succession, is an important consideration for high-speed professional and high-end, as well as typical, consumer cameras. At present, the duration that a digital camera can sustain for a high burst rate capture is very limited, e.g., typically two seconds or more between successive frames, due to the time required for image processing and compression. Furthermore, cameras capable of high speed image capture are typically high-end professional cameras with electronic drives and a large amount of memory, which can be large and expensive and make such systems undesirable for the typical consumer market.
Accordingly, a simple, low-cost and high quality digital imaging system for high speed image capture is desired which overcomes the problems discussed above with the conventional systems.

Analog buffer memory for high-speed digital image capture


The present invention is directed to nucleic acid sequences for constitutive triple response mutants and corresponding amino acid sequences. Several ctr mutations are included within the scope of the present invention. The nucleic acid sequences set forth in SEQUENCE ID NUMBERS 1, and 3-6 as well as amino acid sequences set forth in SEQUENCE ID NUMBERS 1 and 2 are particular embodiments of the present invention.

Ethylene is one of five well-established plant hormones. It mediates a diverse array of plant responses including fruit ripening, leaf abscission and flower senescence.
The pathway for ethylene biosynthesis has been established (FIG. 1). Methionine is converted to ethylene with S-adenylmethionine (SAM) and 1-aminocyclopropane-1-carboxylic acid (ACC) as intermediates. The production of ACC from SAM is catalyzed by the enzyme ACC synthase. Physiological analysis has suggested that this is the key regulatory step in the pathway. This enzyme has been cloned from several sources (Sato and Theologis, 1989; Van Der Straeten et al., 1990; Nakajima et al., 1990). The conversion of ACC to ethylene is catalyzed by ethylene forming enzyme (EFE), which has been recently cloned (Spanu et al., 1991). Aminoethoxy-vinylglycine (AVG) and .alpha.-aminoisobutyric acid (AIB) have been shown to inhibit ACC synthase and EFE respectively. Ethylene binding is inhibited non-competitively by silver, and competitively by several compounds, the most effective of which is trans-cyclooctane.
Etiolated dicotyledonous seedlings are normally highly elongated and display an apical arch-shaped structure at the terminal part of the shoot axis; the apical hook. The effect of ethylene on dark grown seedlings, the triple response, was first described in peas by Neljubow in 1901. In Arabidopsis, a typical triple response consists of a shortening and radial swelling of the hypocotyl, an inhibition of root elongation and an exaggeration of the curvature of the apical hook (FIG. 2A). Etiolated morphology is dramatically altered by stress conditions which induce ethylene production the ethylene-induced "triple response" may provide the seedling with additional strength required for penetration of compact soils, see Harpham, N. V. J. et al., Annals of Bot., 68:55 (1991). Ethylene may also be important for other stress responses. ACC synthase gene expression and ethylene production is induced by many types of biological and physical stress, such as wounding and pathogen infection, see Boller, T., in The Plant Hormone Ethylene, A. K. Mattoo and J. C. Suttle eds., 293-314 (1991), CRC Press, Inc. Boca Raton and Yu, Y. et al., Plant Phys., 63:589- 590 (1979).
A collection of mutants affected in this response has been isolated. One class, the ein mutants (ethylene insensitive), are completely insensitive to ethylene. A second class of mutants are affected in only subset of the seeding responses. The hls1 mutant (hookless) completely lacks an apical hook either in the presence or absence of ethylene.
Constitutive hormone response mutants have been useful in elucidating mechanisms that underlie other hormone-mediated responses (e.g. yeast mating factor, Blinder et al., 1989).
Despite the information known about ethylene biosynthesis, how plants perceive and transduce hormone signals is almost completely unknown. While many of the components found in animal signal transduction chains have been found in plants, including kinases, and G proteins, no definitive correlation of these signal transducers with any hormone signal has been established. Elucidation of the complex role of these signal molecules would be greatly aided by the isolation of gene mutations which are affected in different steps in the signal transduction pathway.
The present invention addresses these important needs. A novel Arabidopsis thaliana mutant has been identified that constitutively exhibits seedling and adult ethylene responses in the absence of the hormone. The constitutive triple response (ctr) mutants display the "ethylene" phenotypes even in the presence of inhibitors of ethylene biosynthesis or receptor binding. ctr1 has a dramatically altered adult morphology that can be phenocopied in wild-type plants by growth in 1 ppm ethylene. Seedling and adult ctr1 plants show high-level constitutive expression of mRNAs for all known ethylene-transduction of the ethylene signal. Genetic, molecular and biochemical characterization of the CTR1 gene and protein product is set forth in the present invention. Genetic characterization of the interactions among modulatory components of the ethylene action pathway will provide insight into how plant hormones function. Thus, the quality, quantity and longevity of food, such as fruits and vegetables, and other plant products such as flowers, will be improved for market in both developed and undeveloped countries.

Constitutive triple response gene and mutations

The Trustees of the University of Pennsylvania


A motor vehicle has an imaging device for generating an image of a radiation pattern on the terrain surrounding the motor vehicle. A detecting device is provided for the multiple sequential detection of images of the radiation patterns that are influenced by the terrain. A processor device is also provided. The processing device is designed such that an obstacle in the terrain is detected based on the difference between directly or indirectly sequentially detected images of the radiation pattern.

The invention relates to a motor vehicle. From U.S. Pat. No. 6,285,778, a detector for the motor vehicle environment is known by which a two-dimensional matrix pattern, particularly a dot matrix, is projected into an area to be observed, and the corresponding light pattern is photographed. A comparison between the photographed light pattern and a stored reference pattern, which corresponds to the light pattern on a flat road, forms the basis of the recognition of obstacles.
This solution has several disadvantages. In order to generate a two-dimensional light pattern that is used for the detection of obstacles in a certain area, it must be radiated onto the entire surface to be sensed. A relatively high luminous power is required for this purpose. Small obstacles between the dots of the light pattern may remain undetected. The assignment of the detected position of the dots to the desired positions is problematic in the case of larger obstacles. In addition, the comparison between the photographed surface-covering two-dimensional light pattern and the stored two-dimensional reference pattern for the detection of obstacles is computationally intensive. An unambiguous assignment of the individual dots in the photographed light pattern to their corresponding desired positions is not always possible. When the patterns of two adjacent vehicles with the same system overlap, the light patterns of one vehicle may overlap those of the other vehicle. No meaningful possibility is indicated to integrate the system in the motor vehicle.
It is therefore an object of the invention to provide a technical teaching for recognizing obstacles in the environment of a vehicle that can be implemented in an economical fashion.
This object is achieved in accordance with the invention. Advantageous further developments of the invention are described herein.
A motor vehicle according to the invention includes (a) an imaging device for generating an image of a radiation pattern in the environment of the motor vehicle, (b) a detecting device for the multiple, sequential detection of images of the radiation pattern influenced by the environment, and (c) a processor device which is arranged such that, based on the difference between directly or indirectly sequentially detected images of the radiation pattern, an obstacle or a turn in the road is detected in the environment.
As a result of the fact that obstacle recognition is based on a difference between successively detected images of the radiation pattern, the obstacle recognition can easily be implemented. A reference pattern that was stored beforehand during manufacturing is not absolutely necessary but may nevertheless be provided for additional purposes. The invention can thereby be put into practice in an economical fashion. As a result, the reliability of obstacle detection can also be improved.
In this case, the imaging device may include an electromagnetic radiation source, such as a laser, for in particular visible radiation or infrared radiation and/or a suitable imaging lens system, for example, a cylindrical lens, for generating a continuous line as a radiation pattern.
The radiation pattern is preferably further developed in an essentially stripe-shaped fashion, for example, as a curved line or as a boundary consisting of several segments. According to a preferred further development, the imaging device is arranged such that the image of the radiation pattern forms an essentially closed ring around the motor vehicle. As an alternative to the above, the radiation pattern surrounds the motor vehicle partially.
As a result, an image of the radiation pattern can be generated repeatedly in a reliable manner with low hardware expenditures and power expenditures. The detection of images of the radiation pattern, and of differences between images and thus of obstacles, can be reliably carried out at low computing expenditures.
It is advantageously provided that the detecting device, which detects the image of, for example, the lines in the environment of the vehicle, is synchronized with the corresponding radiation source. A power-saving pulsed operation is thereby made possible.
The detecting device may, for example, be a digital camera adapted to the wavelength of the imaging device, particularly its radiation source. There may, for example, be between 10 milliseconds and 3 seconds between directly sequential detections of the image of the radiation pattern. The in-between time may depend on the current vehicle speed, for example, such that, in each case, with a movement of the motor vehicle by 0.1 meters, the detection of an image of the radiation pattern is triggered automatically.
When the radiation pattern is recognized by the processor device, the segmentation in the sense of the image processing is preferably carried out by use of the special characteristics of the radiation pattern, such as the luminosity, the wavelength and/or the line width.
An electronic obstacle map is advantageously prepared by use of the obtained information. This electronic obstacle map can be changed to a form that can easily be interpreted by the driver of the vehicle and can be displayed, for example, on the vehicle video screen or a heads-up display. Based on the detection of an obstacle, a visual or acoustic warning signal can be emitted.
It is preferably provided that, on the basis of the curvature of the radiation pattern at the obstacles, not only their distance and the direction relative to the coordinate system of the motor vehicle are determined but, by means of a comparison of several chronologically successive detections, their relative speeds with respect to the vehicle coordinates are also computed.
The speed of the obstacles relative to the road can advantageously be computed from the relative speed of the obstacles in the coordinates of the vehicle and from the knowledge of the vehicle speed relative to the road. In this manner, a motor vehicle can differentiate between static obstacles, such as road boundaries, and the mobile obstacles, for example, a pedestrian who wants to cross the road in front of the vehicle. This differentiation is of essential significance when designing algorithms, for example, for avoiding collisions, for the protection of pedestrians, and/or for pre-crash algorithms.
The vehicle dynamics of the motor vehicle can preferably be influenced by the obtained information concerning the environment of the motor vehicle. This may be further developed as an automatic braking in front of obstacles if these are situated in the precalculated trajectory of the vehicle, and/or as an evasion with respect to recognized obstacles.
Particularly preferably, the imaging device includes an infrared laser beam device, which is further developed with a special lens system which optically transforms the laser beam such that, from its installed position in the motor vehicle, aimed at a straight road that is free of obstacles, the laser beam generates a straight or curved line. A curved cylindrical lens can, for example, be used as the optical device.
As an alternative to the above, a laser beam can be caused to carry out a rapid movement by way of a rotating mirror or, for example, by way of an optical element moved by a piezoelectric transducer, so that the one-dimensional laser beam generates a two-dimensional figure in the environment of a motor vehicle.
The imaging device is preferably set up such that, when it is assumed that an environment does not change relative to the motor vehicle, the image of the radiation pattern rests in the coordinate system of the vehicle or is moved along with the motor vehicle. In contrast to the known LIDAR technology, no precise controlled deflection of the beam in two directions is therefore required for the obstacle recognition. The radiation pattern moves together with the vehicle. The points-in-time for the detection of the current image of the radiation pattern can be automatically computed from the movement of the vehicle, which is detected, for example, by way of wheel sensors. As a result, it is also not absolutely necessary to expose the vehicle environment in a surface-covering manner to a dot matrix radiation and to sense it. The required information concerning the position, the size and, if required, the inherent speed of the motor vehicle can be obtained by means of the inherent speed of the vehicle or a rotation of the door during the opening as soon as these are impacted by the radiation pattern.
The recognition of an obstacle is preferably based on the comparison of the displacement of the image of the radiation pattern and the displacement of other textures and/or edges in the image of the environment detected by the detecting device. It is preferably provided that the presence of obstacles can be assumed if a clearly deviating displacement or curvature of the image of the radiation pattern relative to the edges extracted from the detected image of the environment takes place at certain points of the detected image.
The imaging device and the detecting devices are preferably arranged at a distance from one another. Only in this case can the change of the shape of the image of the radiation pattern be detected due to obstacles. In particular, the imaging device and the detecting device are arranged above one another and, in the vertical direction, are arranged at a mutual distance of, for example, 10 cm.
Preferably in the case of a locked vehicle, a threat of theft or vandalism can be assumed based on the difference between indirectly or directly sequentially (chronologically successively) detected images of the radiation pattern, and a corresponding warning signal is generated, which can be emitted, for example, visually and/or acoustically directly at the motor vehicle or is emitted after a message transmission from the vehicle to a remote unit, for example by way of a mobile radio system at the remote unit.
As a result of a relatively low power consumption of the device in comparison to the systems that require a clearly stronger illumination of the environment, the system can operate particularly in a pulsed operation as a replacement or support of an antitheft warning system.
By means of the detected change of the image of the radiation pattern, such as a line, from one pulse timing to the next, preferably not only the violation of a safety zone is determined but an object classification is also carried out. For example, the approach of a pedestrian can be automatically differentiated from the approach of another motor vehicle because these approaches result in different curvatures of the safety ring. Such a further development has an advantage in comparison to a conventional antitheft warning system which cannot carry out a classification of the objects.
A preferred further development provides that a radiation pattern assigned to the motor vehicle or originating from the motor vehicle or the pertaining imaging device is recognized or can be separated from the radiation pattern of another vehicle in that the detected image corresponds to the generated image with respect to its shape, particularly with respect to its curvature (convex or concave).
A clear differentiability of the image of the radiation pattern of the own vehicle from the perspective of its detecting device from the image of the radiation pattern of another vehicle with the same system offers a significant advantage with respect to the known state of the art.
Advantageously, the imaging device, particularly for the sections of the environment situated laterally with respect to the vehicle, can be cost-effectively and functionally built into a door handle, for example, together with the front end area lighting unit of the vehicle. The detecting device, particularly for the sections of the environment situated laterally with respect to the vehicle, can preferably be built into a lateral mirror of the motor vehicle. For the detection and further processing of the image of the radiation pattern, an existing top view camera system can be used or can be built in together with the latter. The top view camera preferably is a system for displaying to the driver a geometrically transformed camera image of sections of the environment situated laterally with respect to the vehicle. The imaging device for the forward area of the vehicle is preferably cost-effectively and functionally built into a decorative element, for example, a manufacturer's emblem. In this case, the radiation pattern can be deflected, for example, by way of a mirror and/or prism which, in particular, can be hinged.
The deflection of the radiation pattern in a mirror is very advantageous, particularly with respect to better meeting the safety standard for the use of the laser technique in the motor vehicle. As a result, the exit lens system of the laser can be built into the interior of the vehicle in a manner not accessible from the outside. It is therefore not possible to look directly into the exit lens system which, in the case of a relatively high emitted power, could result in possible damage to the retina. The radiation reflected in a deflecting mirror, which according to the invention is emitted, for example, as a line into the environment of the vehicle, is even largely harmless when looking directly into the mirror because, at a certain distance from the lens system, the radiant power is already relatively widely fanned out and can generate a much lower luminous power per unit of surface, for example, on the retina.
Advantageously, a further development of a forward-directed camera system of the vehicle, such as a lane departure warning system, can be used in a cost-effective and functional manner as the detecting device for an area situated in front of the vehicle. The detecting device is preferably constructed in a cost-effective and functional manner as a further development of a backup camera for areas situated behind the vehicle. Since the above-mentioned camera systems already have high-power image processing units, the invention or its further developments can be implemented at low expenditures.
Particularly when the imaging device and/or the detecting device is integrated in a side mirror of the motor vehicle, it is preferably provided that, based on the difference between sequentially detected images of the radiation pattern, an obstacle is detected which hinders the opening of a vehicle door.
Particularly preferably, it is provided that the time between the sequential generation of images of the radiation pattern and/or the successive detections of images of the radiation pattern influenced by the environment depends on the vehicle movement, for example, such that repeatedly, after a movement of the vehicle by a predefined distance of, for example, 10 to 50 centimeters, a generating of an image and/or a detecting of an image is triggered. The measuring of the predefined distance can be carried out, for example, by use of wheel sensors present in the vehicle. Additionally, the distance between two neighboring detections of the environment can be made dependent on the current speed range of the vehicle. As a result, parking and maneuvering with high demands on the precision of the obstacle detection and a detection of the environment, for example, for pre-crash applications for the higher speed range, can be supported by higher demands on the real-time cap ability.
Preferably, based on sequentially detected images of the radiation pattern, the time between the sequential detection of the images and the vehicle speed, information concerning the vehicle environment, particularly concerning the presence, the size, the shape and the relative speed of the obstacles in the environment of the vehicle, is obtained, which can be further processed as the basis of the triggering of automatic warning functions and/or the intervention in the dynamics of a vehicle.
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.

Bayerische Motoren Werke Aktiengesellschaft


Wellness footwear that promotes proper gait and strong feet is provided. The footwear can include a sole. The footwear can also include a securing upper arranged with the sole and configured to securely hold a foot of a user on a footbed so as to substantially prevent lateral movement of the foot with respect to the footbed and allow one or more of a big toe and remaining toes of the user to be at least partially uncovered and exposed. A toe aligner structure can be arranged between the securing upper and the sole and configured to extend between the big toe and remaining toes of the user so as to direct a force against the big toe in a direction away from the remaining toes during standing, walking, running, swimming, and other movements when muscles of the foot are in use.

Modern footwear often has toe boxes that are too narrow for the toes of a wearer to spread out and work as nature intended. Such footwear can confine the foot thereby deforming and misaligning the foot and toes over time. In particular, the toes can be forced to angle into each other, causing the big toe to point inward towards the remaining toes rather than fanning out to stabilize the body when in a standing position or in motion. This phenomenon can be observed by referring to FIGS. 1A and 1B which compare a healthy aligned foot with a misaligned foot, respectively. The misaligned foot is characterized in FIG. 1B as having a relatively large hallux valgus angle, HV.
Modern footwear has been shown to cause or worsen foot ailments such as, but not limited to, bunions, plantar fasciitis, hallus valgus, heel spurs, bone spurs, corns, tailors bunions, hammer toes, nueromas, and collapsed arches. Ailments of the foot often correspond to upper body ailments such as, for example, skeletal and muscular misalignment in ankles, knees, hips, back, and neck.
In a healthy foot, the toes move and spread out to help balance the body and distribute pressure on the foot. This enables the arch, tendons, bones and muscles of the foot to work in conjunction to support the body. It is the big toe that acts as a counterbalance to the remaining toes and the heel. The big toe, remaining toes, and heel operate to anchor the arch of the foot to support the body. As in any structure that forms an arch, such as a bridge for example, the arch can support tremendous amounts of weight from above. But if pressure is applied from beneath the curve of the arch, the arch is easily weakened and can collapse. This concept also applies to an arch of the foot and it is why that for so many people the use of an arch support can actually weaken the strength of the foot.
In addition to anchoring the arch, the position of the big toe is crucial during toe-off at the end of the natural gait cycle when walking or running. The big toe supports the weight of the body when pushing off at the end of a stride. If the big toe is not properly aligned, the first metatarsal joint bears the weight of the body and over time the foot goes out of alignment. The misalignment is shown in FIG. 1B where the big toe, first metatarsal joint, and heel are not arranged in a straight line. This misalignment prevents the big toe from acting as the counterbalance to the remaining toes and the heel. This can result in the formation of a bunion, plantar fasciitis, collapsed arches, hammertoes, and other ailments.
Accordingly, there exists a need for footwear that can realign a foot by moving the toes and foot into their healthiest position in order to counteract the damage that modern footwear can cause. Such footwear can be beneficial for the foot when standing, walking, running, swimming, and during other activities where the muscles of the foot are in use.


A pliable electrophoretic display device having a deformation-resistant memory characteristic is provided by covering a plurality of partitioning walls defining display sections containing a dispersion liquid with electrophoretic particle dispersed therein with an expandable ceiling sheet. Such a ceiling sheet is formed by applying a hardenable precursor liquid, which is immiscible with the dispersion liquid, over the partitioning walls containing the dispersion liquid and hardening the precursor liquid in situ by exposure to light, heat or by drying.

The present invention relates to an electrophoretic display device and a process for production thereof.
Along with development of data processing apparatus and devices in recent years, there is an increasing demand for so-called xe2x80x9cpaper-like displayxe2x80x9d which is rewritable electronic paper satisfying the convenience of paper medium and electronic medium function for a portable personal computer. A display device used for such a paper-like display should require a small power consumption, be thin and have a flexibility like paper durable against flexure. One sheet or plural sheets of such display devices are used as a paper-like display.
Display devices in compliance with such a demand have been a subject of extensive research and development. Among these, a liquid crystal display device wherein an alignment of liquid crystal molecules is electrically controlled to change optical characteristics has been extensively developed and commercialized as a display device satisfying the demand described above. However, such liquid crystal display devices are still accompanied with problems of visual load on human eyes, such as difficulty of recognizing characters on display depending on a viewing angle or due to reflection light, and flickering and low luminance of light source. Further, because of necessity of alignment control of liquid crystal molecules and accurate control of liquid crystal cell gap, it is difficult to also satisfy a flexibility of the device.
As a type of reflection display device capable of realizing a flexibility, there has been known an electrophoretic display device wherein colored charged particles are moved within an insulating liquid to effect a display (e.g., as disclosed in U.S. Pat. No. 3,668,106). FIGS. 4A and 4B are schematic sectional views for illustrating an organization and an operating principle of a representative one of such an electrophoretic display device.
Referring to FIGS. 4A and 4B, an electrophoretic display device includes an electrophoretic dispersion liquid comprising an insulating liquid (colored dispersion medium) 47 and colored charged particles (electrophoretic particles) 46 dispersed therein, and a pair of oppositely disposed pair of electrodes 42 and 43 sandwiching the electrophoretic dispersion liquid. By applying a voltage across the electrophoretic display device via the electrodes 42 and 43, the electrophoretic particles 46 are electrophoretically moved to and fixed on either one of the electrodes 42 and 43 which are biased to mutually opposite polarities to effect a display. The display is effected based on the color of the electrophoretic particles 46 and the dyed color of the colored dispersion medium 47. More specifically, in a state shown in FIG. 4A wherein the electrophoretic particles 46 are attached to a first electrode 42 closer to a viewer, the color of the particles 46 is displayed. On the other hand, in a state shown in FIG. 4B wherein the particles are moved and attached to a second electrode 43 more remote from the viewer, the color of the dispersion medium 47 is displayed.
The display device can be formed in a thin shape In principle and formed in a device retaining some degree of flexibility by using flexible materials for the substrates and other associated members including electrodes.
Further, a display picture retention characteristic (or a display memory characteristic) is provided by making the circuit open immediately after the voltage application to hold some charge at the electrodes exerting a Coulomb force for attracting or adsorbing the colored electrophoretic particles.
By suppressing the reduction in charges held by the electrodes, e.g., by disposing an insulating layer of an appropriately selected material, the electrophoretic particles can be retained on the electrodes for a relatively long period, so that it is possible to continually retain a display memory characteristic for long hours without supplying any external power.
An electrophoretic display deice operates at a relatively low current compared with other types of display devices, such as a liquid crystal device, in principle, and can further reduce the average power consumption in a case where a frequent rewriting of display is not required.
However, a conventional electrophoretic display device is accompanied with the following problems.
A first problem is encountered at the time of injecting the electrophoretic dispersion liquid between the substrates in the process for producing the electrophoretic display device. In an example of the production process, two substrates for constituting the electrophoretic device is applied to each other while leaving a port for injecting the electrophoretic dispersion liquid. Thereafter, the electrophoretic dispersion liquid is injected through the injection port, but the smooth injection thereof is obstructed by the presence of a spacer and partitioning walls for keeping the spacing between the substrates at a constant. Further, in the case of injecting the electrophoretic dispersion liquid from an edge of the device toward the edge on the opposite side, the dispersion medium can be easily transferred but the electrophoretic particles are liable to be caught at the spacer and partitioning walls, so that the electrophoretic particle concentration is liable to be high near the injection port and lowered at points leaving away from the injection port, thus adversely affecting the display uniformity.
In another example of the production process, a lower substrate is first provided with spacer and partitioning walls, an electrophoretic dispersion liquid is uniformly distributed thereover, and thereafter an upper substrate is bonded to the lower substrate to seal the periphery of the structure. According to this process, a uniform concentration of electrophoretic particles over the planar extension of the device can be realized, but a problem of entrainment of air bubbles is liable to occur at the time of bonding the upper substrate.
A second problem is encountered as a difficulty of realizing a device showing paper-like flexibility. This is because an electrophoretic. display device is composed of two substrates so that it is difficult to absorb a difference between an inner circumference and an outer circumference caused when the device is flexurally deformed even if the two substrates are composed of flexible materials. Thus, the flexured device is liable to result in a stiff touch.
A third problem is liable to be encountered when a flexible device is flexurally deformed. Thus, at the time of deformation, the insulating liquid therein is flowed to push the electrophoretic particles adsorbed by electrostatic interaction with the electrode retention charge, so that the display is liable to be deformed to remove the display memory characteristic.
A generic object of the present invention is to provide an electrophoretic display device and a process for production thereof having solved the above-mentioned problems of the prior art.
A more specific object of the present invention is to provide an electrophoretic display device having a flexibility susceptible of easily following flexural deformation.
Another object of the present invention is to provide an electrophoretic display device free from loss of display memory characteristic even when subjected to deformation.
A further object of the present invention is to provide a process for producing an electrophoretic display device allowing easy injection and sealing of an electrophoretic dispersion liquid.
According to the present invention, there is provided an electrophoretic display device for effecting a display by moving electrophoretic particles, comprising: a flexible support sheet, a plurality of partitioning walls formed on the support sheet, a ceiling sheet disposed over the partitioning walls and opposite to the support sheet so as to form a plurality of cells defined by the support sheet, the ceiling sheet and the partitioning walls, and a electrophoretic dispersion liquid filling the cells and comprising an insulating liquid and electrophoretic particles dispersed in the insulating liquid, wherein the ceiling sheet is flexible and also capable of expansion and contraction upon application of a planar stress.
According to another aspect of the present invention, there is provided a process for producing an electrophoretic display device for effecting a display by moving electrophoretic particles dispersed in an insulating liquid while changing a direction of electric field acting on the electrophoretic particles, comprising the steps of:
disposing a plurality of partitioning walls on a flexible support sheet to form a plurality of sections defined by the support sheet and the partitioning walls,
injecting an electrophoretic dispersion liquid comprising an insulating liquid and electrophoretic particles dispersed therein into the sections on the support sheet,
applying a hardenable liquid immiscible with the insulating liquid over the partitioning walls and the electrophoretic dispersion liquid therein, and
hardening the hardenable liquid to form a ceiling sheet thereby defining a plurality cells within which the electrophoretic dispersion liquid is sealed up.
Thus, by using a ceiling sheet capable of expansion and contraction upon application of a planar stress, i.e., a stress acting in a plane extension thereof, the electrophoretic display device of the present invention becomes easily pliable in response to flexural deformation. Further, a flexural deformations stress acting on the device can be absorbed by deformation of the ceiling sheet, so that the flow of the electrophoretic display device in the device is suppressed to provide the electrophoretic display device with a better display memory characteristic.
Further, according to the process of the present invention, it is possible to produce an electrophoretic display device, while easily achieving uniform distribution and sealing into respective display sections of the electrophoretic dispersion liquid.

Electrophoretic display device and process for production thereof


A system and method for coordinating advertisements on multiple playback devices during playback of heterogeneous content are provided. In general, a virtual group of playback devices or users of the playback devices is formed and managed by a virtual group (VG) control function. In operation, the VG control function operates to coordinate advertisement slots in heterogeneous content being played by the playback devices and provide targeted advertisements to the playback devices for insertion into the coordinated advertisement slots. The targeted advertisements may be, for example, targeted advertisements for each user or playback device, targeted advertisements for subsets of the users or playback devices in the virtual group, targeted advertisements for the virtual group, targeted complementary advertisements for subsets of users or playback devices in the virtual group, or targeted complementary advertisements for the virtual group.

There is an increasing trend to view video content on devices other than a television such a personal computer, an Apple iPod®, a Microsoft Zune™, a mobile phone, a Personal Digital Assistant (PDA), or the like. Unlike a television, these devices primarily have a one-to-one mapping with a user. As such, a first user may be watching video content on his device while a second user that is proximate to or otherwise associated with the first user may be watching different content on her device. For example, consider three users A, B, and C that are in close physical proximity such as in a living room of their home. User A is viewing previously downloaded or Video-on-Demand (VOD) content on a wireless handheld device, such as a Microsoft Zune™, Nintendo DS®, or other WiFi-capable playback handheld video device. User B is watching content on a High Definition Television (HDTV) device provided by an associated set-top box that functions as a Digital Video Recorder (DVR) and a digital signal decoder. User C is watching a downloaded video from a service such as Apple iTunes® on a personal computer. Alternatively, all three users may be viewing content provided by a single provider, such as a cable television provider, but may be still watching different, or heterogeneous, content. In such a system, it is desirable to coordinate targeted advertisements at multiple playback devices during playback of heterogeneous content.

Coordinating advertisements at multiple playback devices