A combination walking stick and blind which includes a bi-support blind characterized by a pair of longitudinally half-round, elongated supports pivotally joined at one end, with the flat sides of the supports positioned in facing relationship and the supports fitted with camouflage netting or fabric designed to deploy when the bottoms of the supports are extended in pivoted relationship, and wrapped around the supports when and the supports are aligned, to define a walking stick. In another embodiment three supports define a tri-support blind, which supports may be configured as one-third-round supports that nest when joined together to define a walking stick. Camouflage netting or fabric is attached to the supports by means of looped securing straps. In another aspect of the tri-support blind, the supports may be characterized by two longitudinally half-round supports and one support having a rectangular cross-section, that longitudinally nest to define a walking stick having an ellipitical cross-section when the camouflage netting or fabric is wrapped on the composite supports. In another embodiment, four such supports define a quad-support blind, two of which supports include longitudinally half-round, elongated supports and the other two supports having a rectangular cross-section. The supports may be nested together and the camouflage netting or fabric wrapped around the supports to define a walking stick. Finally, the four supports may include longitudinally quarter-round supports which nest to define a walking stick having a circular cross-section.

1. Field of the Invention
This invention relates to hiking and hunting and more particularly, to a combination walking stick and blind which is typically characterized by a bi-support blind, a tri-support blind and a quad-support blind. In a preferred embodiment, the bi-support blind is characterized by a pair of longitudinally half-round, elongated supports pivoted at a grip end and fitted with a shaped, flexible camouflage netting or fabric panel having a desired camouflage pattern, such as the "TREBARK".TM. or "REAL TREE".TM. camouflage pattern, in non-exclusive particular and a securing strap extending from the bottom netting margin of the camouflage netting or fabric panel. Accordingly, the bi-support blind can be deployed by extending the non-pivoted, ground-engaging, tapered ends of the half-round supports outwardly to stretch the camouflage netting or fabric panel in a triangular configuration and the sharpened points of the half-round supports may be forced into the ground to provide the desired camouflage. The half-round supports can be re-pivoted into alignment along the flat edges thereof and the camouflage netting or fabric panel wrapped around the composite support and secured by the securing strap, to facilitate use of the bi-support blind as a walking stick.
In another preferred embodiment of the invention, a tri-support blind is provided wherein three elongated supports having essentially triangular-shaped cross-sections which nest or fit together longitudinally to define a composite support having a circular cross-section, are provided and a camouflage netting or fabric panel is secured to each of the supports by means of elastic support mount loops, straps or ties to facilitate slidable adjustment of the camouflage netting or fabric panel with respect to the respective supports. Alternatively, the supports can be characterized by two longitudinally half-round elongated members, with an elongated support having a rectangular cross-section sandwiched between the half-round members to enhance the rigidity of the composite support in walking stick configuration. Loop-pile securing straps are attached to one of the segments of the camouflage netting or panel for securing the camouflage netting or fabric panel in wrapped configuration around the nested supports.
In yet another preferred embodiment of the invention, a quad-support blind is provided, with four elongated supports which may, in one aspect, be characterized by a longitudinal quarter-round configuration in which the supports nest together to define a round composite walking stick, with a length of camouflage netting or fabric panel connected to the supports. Alternatively, the four elongated supports may be characterized by a pair of half-round members and a pair of elongated members having rectangular cross-sections arranged between the half-round supports, either longitudinally or laterally, to define a generally elliptically-shaped walking stick. As in the case of the tri-support blind, the camouflage netting or fabric panel in the quad-support blind may be attached to the respective elongated supports by means of elastic support mount loops, straps or ties to facilitate slidably positioning the camouflage netting or fabric panel on the respective supports. Deployment of both the tri-support blind and the quad-support blind includes spacing the respective supports to stretch the camouflage netting or fabric panel between the supports and driving the sharpened ground-engaging ends of the supports into the ground in a desired configuration. The supports and camouflage netting are deployed into walking stick configuration by initially joining the supports into the longitudinally nested composite configuration described above, wrapping the camouflage netting around the composite supports and securing the netting in position by means of loop-pile securing straps.
One of the problems associated with hunting various types of game, including deer, elk, turkey and the like, is that of concealment, particularly under circumstances where there is little or no natural cover in the hunting area. Typical hunting stands and blinds include platforms mounted in trees, triangular-shaped, portable tripod stands having a rotatable, saddle-type seat at the top and large, cumbersome, portable stands constructed of plywood or cardboard, which are difficult to transport, deploy and use effectively. Furthermore, since wild game typically have very sharp eyesight and are sensitive to even small movements, the use of camouflage clothing alone is sometimes insufficient to facilitate close approach by the game. Moreover, a close approach by wildlife to the hunter is particularly necessary during bow and arrow hunting and in the case of wildlife observation and photography, additional cover, whether natural or artificial, is usually necessary to faciliate a sufficiently close approach by wild animals and birds.
2. Description of the Prior Art
Various types of collapsible shelters, blinds and other structures are known in the art. U.S. Pat. No. 1,415,482, dated May 9, 1922, to R. T. Reed, details a "Collapsible Tent" which is constructed somewhat like a teepee, with a frame of flexible fabric covering the frame, wherein the frame is secured at the top to facilitate folding of the frame inwardly and wrapping of the fabric around the frame when the frame is in folded configuration. A "Collapsible Sportman's Hut and Duck Blind" is detailed in U.S. Pat. No. 2,783,766, dated Mar. 5, 1957, to C. A. Kohlbeck. The device is also shaped generally in the configuration of a teepee, with multiple supports attached to the top by means of a rope and fitted with a flexible fabric outer covering. The entire structure can be folded inwardly and carried to various locations when moved. A "Convertible Windbreak" is detailed in U.S. Pat. No. 3,537,688, to B. Stein. The windbreak includes a rectangular strip of fabric having grommets at the corners and along the top and bottom edges thereof and multiple, elongated stakes fitted with hooks for engaging the grommets and deploying the windbreak in position to block the wind. U.S. Pat. No. 3,642,318, dated Feb. 15, 1972, to Ralph L. Avant, details a "Hunter's Blind". The blind includes a collapsible structure having hinged elements that are covered with a flexible material which may include a camouflage pattern. The device also includes an adjustable seat. U.S. Pat. No. 3,799,608, dated Mar. 26, 1974, to Frank D. Smutny, details a "Portable Blind" having a collapsible frame with a folding seat. The lower portion of the frame is covered with a camouflage material, while the upper part of the frame is covered with a net-like material that permits the hunter to see outside the blind. The lower camouflage material includes a pair of front flap members having registering grommets and the net-like material includes a movable top portion having an elastic band for moving the top portion from a closed position to an open position and allowing the hunter to stand up in the blind for shooting purposes. An arcuate hook element is mounted on the lower forward end of the top portion of the net-like material and is extended through the registering grommets for selectively maintaining the blind in a closed position. U.S. Pat. No. 3,902,264, dated Sep. 2, 1975, to Theodore N. Radig, details a "Blind For Hunters and the Like". The blind is portable and includes a frame structure having a ground-engaging, portable base. A collapsible shroud is carried by the frame to present a concealment cover and the frame structure includes multiple shroud-supporting elements, of which at least two define a forward pair of elements hinged for movement about the vertical axis. A shiftable positioner mechanism is carried by the frame structure for positioning and releasably holding the forward elements in the first relative disposition presenting the cover and includes means for causing the two forward elements to swing to a second relative disposition partially collapsing the cover, to present an opening and affording an unobstructed forward field of view. A "Wind Shelter" is detailed in U.S. Pat. No. 4,685,484, dated Aug. 11, 1987, to Ted C. Moneta. The wind shelter includes an arm mechanism which urges arm segments interconnecting adjacent posts into a horizontal aligned and opposing position when the wind shelter is in use. The arm mechanism also urges the arm segments toward a position in which they are contiguous along their lengths when the wind shelter is collapsed, for transportation. The fabric of the wind shelter has parallel pockets for receiving posts and an upper flap portion for removably attaching the fabric to the post. U.S. Pat. No. 4,860,777, dated Aug. 29, 1989, to Anthony Orlando, details a "Combination Beach Blanket and Wind Protector Device". The device includes a flexible mat that is movable from a rolled-up, closed, carried configuration to a flat, open configuration wherein the mat is disposed in a substantially horizontal position on a selected ground site. Side and head panels are joined to the mat along fold lines and multiple openings are located in the mat in spaced relationship with respect to the side and head panels. Multiple posts are provided, each of which extends through an opening in the mat for penetration into the ground and fixing the mat in the flat, open position thereon. A first fastening element is joined to the side and head panels and a second fastening element is secured to the post, such that the first and second fastening elements cooperate for mounting the side and head panels on the post, thus locating the side and head panels in an upright position for sheltering an occupant who is lying on the mat. A "Beach Wind-Shielding and Signaling Device" is detailed in U.S. Pat. No. 4,966,181, dated Oct. 30, 1990, to Michael Liberman, et al. The device includes a rectangular fabric article vertically supported on poles on a beach, so that users on the leeward side are shielded from the wind. The device has a color indicia or the like imprinted on the windward side to serve as a location-indicating visual signal. U.S. Pat. No. 5,010,909, dated Apr. 30, 1991, to Thomas J. Cleveland, details a "Knock-Down Deer Blind". The device includes a three-dimensional, rectangular frame provided with an upstanding, flexible sleeve which engages the frame. The lower end of the sleeve may be opened and closed for ingress and egress to the blind and the upper and lower ends of the sleeve include upwardly-directed marginal flaps extending over and under, respectively, the upper and lower ends of the frame. The sleeve is constructed of a material which may have a camouflage design on its outer surface and which is preferably substantially air-impervious. A "Portable Blind" is detailed in U.S. Pat. No. 5,062,234, dated Nov. 5, 1991, to Richard T. Green. The blind includes a length of camouflage material provided with a desired camouflage pattern, which material is stretched between multiple supports embedded in the ground to define discreet panels and conceal a hunter or observer. A camouflage material can be fitted with a drawstring around the top edge thereof and is characterized by cloth or netting. In a most preferred embodiment the elongated supports include a bottom member, a receptacle fitted to the top end of the bottom member for receiving the bottom end of a corresponding top member and an elastic band connecting the bottom end of the top member to the top end of the bottom member. Alternatively, the bottom member may be telescoped into the top member to disassemble the blind and extended from the bottom member to deploy the blind.
It is an object of this invention to provide a portable, lightweight blind which may be carried or used as a walking stick when in non-deployed configuration and operates to facilitate adequate camouflage when in deployed configuration.
Another object of this invention is to provide a portable combination walking stick and blind which is characterized by two or more elongated, longitudinally-nesting supports fitted with a camouflage panel or netting for nesting as a composite to define a walking stick and deployment to stretch the camouflage panel or netting between the supports when used as a blind to conceal a hunter or observer.
Yet another object of this invention is to provide a new and improved bi-support blind characterized by a pair of elongated, longitudinally half-round supports having sharpened ends and pivotally attached at the opposite grip ends from the sharpened ends, with a camouflage netting or fabric panel deployed on the supports such that the supports may be pivotally aligned along facing flat edges and the camouflage netting or fabric panel wrapped around the supports to define a composite support walking stick, and deployed by pivoting the supports to extend the sharpened ends away from each other and stretch the camouflage netting or fabric panel between the supports for use as a blind to conceal the hunter or observer.
Still another object of this invention is to provide a tri-support blind which is characterized by three elongated supports that may have pointed ends and substantially triangular cross-sectional configurations to define a longitudinally nested, composite walking stick configuration, with a camouflage netting or fabric panel connecting the supports, such that supports may be nested together and the camouflage netting wrapped around the supports and secured in place to define a walking stick and the supports may be alternatively deployed in spaced relationship with respect to each other by driving the pointed ends in the ground and stretching the camouflage netting or panels between the supports to define a blind for concealing the hunter or observer. Alternatively, two of the supports may be characterized by half-round supports, with the third support having a rectangular cross-sectional configuration, such that the third support is nested between the flat sides of the first two supports when the supports are deployed in composite walking stick configuration.
A still further object of the invention is to provide a quad-support blind characterized by four pointed, elongated supports, two of which may be half-round in longitudinal configuration and the other two having rectangular cross-sectional configurations, with a camouflage netting or fabric panel attached to the supports. Accordingly, the supports can be longitudinally nested together, with the two supports having a rectangular cross-sectional configuration nested either laterally or longitudinally between the flat sides of the two half-round supports, to generally define an elliptical shaped composite walking stick, with the camouflage netting or fabric panel wrapped around the walking stick and secured in place. The supports can correspondingly be deployed to define a hunter's or observer's blind by extending the supports in spaced relationship with respect to each other and driving the sharp ends thereof into the ground in a desired configuration to stretch the camouflage netting or fabric panels between the supports.
These and other objects of the invention are provided in new and improved portable combination walking sticks and blinds which are characterized by two or more elongated supports of desired matching and nesting cross-sectional configuration to facilitate longitudinal nesting or fitting together to define a walking stick having connecting camouflage netting or fabric. The camouflage netting or fabric may be wrapped around the composite supports when the supports are nested in walking stick configuration or extended between the supports when the supports are driven into the ground to define the blind.


A die-cut permanent marking article for use with an elongate object, consisting of a strip of low molecular weight heat-sensitive, transparent polymeric film having an upper and a lower surface, at least a portion of the lower surface being capable of self-adherence, at least a portion of the upper surface being imprintable, the polymeric film being fusible by the application of heat, but remaining transparent even after application of heat such that any marking placed on any portion of the article remains readable even if covered by one or more overwrapping portions of the strip.

1. Field of the Invention
The present invention relates to identification of elongate objects using indicia wherein a mark is both rendered permanent and protected using an optically clear means of attachment.
2. Description of the Related Art
It is frequently necessary to identify components in electrical assemblies, particularly where a multiplicity of wires and/or cables need to be identified. Various marking systems for wire cables and the like are known in the art.
Wires and cables have been identified by impressing characters into the insulation surrounding the wire. This has the disadvantage of possible damage to the insulation. Early attempts to create permanent marking assemblies employed plastic tubes which slip over the cable. These may be loose or may use heat-shrink technology as disclosed in U.S. Pat. No. 3,894,731. However, these assemblies require application during installation, since they must be slipped onto or over an unterminated wire. This limits any marking of already installed cable, or redesignation.
Later, heat-shrink sleeves were formed as wrap-around versions, which employed strips of heat-shrink film. It is necessary to secure the final "wrap" to prevent the formation of a free end. This is known in the industry as flagging. However, both tubular and wrap-around shrink sleeves employ radial shrinkage. The identification is usually printed or typed onto the article, and rendered permanent by a heat treatment. This is referred to as "permatization", and may be accomplished by heating in an oven or subjecting to infrared radiation. This is expensive, and may not be effective for elongate articles which are dark in color.
U.S. Pat. No. 4,569,759, (Brewers) discloses an adhesive tape construction used for identification markers to be applied to wire cables or switch structures. A pressure-sensitive adhesive layer is applied to the lower surface of a transparent substrate, which has an opaque ink-receptive area. The tape is cut into individual strips which are adhesively attached side-by-side on a release carrier material. The information is inscribed on the ink-receptive area. The marker strip is then removed from the release liner by peeling back the tape, and applied by attaching the head section to the wire and wrapping it upon itself so that the width dimension of the tape becomes the length of the marker. Multiple layers of strips may be arranged upon one another.
U.S. Pat. No. 4,465,717, (Crofts et al.) discloses a means for marking elongate objects in which a carrier supports a strip of marking material consisting of a heat-shrink film coated with a heat-reactive adhesive. Two stripes of pressure-sensitive adhesive are applied to the heat-reactive adhesive. The identification is then applied to the strip on the surface opposite to that holding the adhesive. The marker is imprinted and applied temporarily via the pressure-sensitive adhesive. Permanent attachment is achieved by applying heat which activates the heat-reactive adhesive and shrinks the sleeve.
U.S. Pat. No. 4,246,709, (Selleslags) discloses a holder for an identification sheet which comprises two transparent films bonded by their side edges. When heated, the composite curls relative to a single axis. For use, the identification is added as a sheet between the two films. The composite is then applied and heated, whereupon it curls around the wire until it conforms. A hot-melt adhesive may be used to attach the identification permanently to the wire.
U.S. Pat. No. 4,868,023, (Ryan et al) discloses indicia which are applied to a polyolefin surface using a pigmented ink, which cures at elevated temperatures to provide a permanent mark.
It has now been discovered that a marking article may be formed via wrap-around techniques to provide either a temporary or a permanent marker. This marker is flag-free and has permanent readability due to protection afforded by an optically clear wrap of the article.
Further, because the polymeric film used in the article is dimensionally stable, the imprinted area does not suffer from distortion of the markings thereon.

Minnesota Mining and Manufacturing Company


An image forming apparatus includes an image carrier removably installed in the apparatus to carry an image; a transfer member contacting with the image carrier to transfer the image onto the transfer member or a recording medium; a contact and separation mechanism causing the transfer member to contact with or separate from the image carrier; and a removable unit removably installed in the apparatus from the same direction as an installation direction of the image carrier to be disposed proximal of the image carrier and the transfer member in the installation direction, and at least partially overlapping the image carrier and the transfer member as viewed in the installation direction. The removable unit interferes with the contact and separation mechanism and is prevented from being installed in the apparatus, when the transfer member is separated from the image carrier by the contact and separation mechanism.

1. Field of the Invention
The present invention relates to an image forming apparatus, such as a copier, a printer, a facsimile machine, or a multifunction machine combining several of the functions of these apparatuses, particularly to an image forming apparatus including an image carrier removably installed therein.
2. Description of the Related Art
In an image forming apparatus such as a copier or a printer, in some cases an image carrier such as a photoconductor drum is removably (i.e., replaceably) installed in the body of the image forming apparatus. The image carrier such as a photoconductor drum may be a component of a process cartridge such that, when the process cartridge in the body of the image forming apparatus is replaced with a new process cartridge, the image carrier is also replaced with a new image carrier.
Further, the image forming apparatus may be configured such that a transfer member of a transfer device is contactable with and separable from the image carrier, and that the transfer member is brought into contact with the image carrier in a normal image forming operation and is separated from the image carrier in, for example, replacement of the image carrier. In this type of image forming apparatus, the image carrier is replaced when the transfer member is separated therefrom. This configuration therefore reduces the possibility of the image carrier and the transfer member interfering with each other and damaging respective surfaces thereof in replacement work.
According to this configuration, however, an operator may mistakenly operate the image forming apparatus with the transfer member separated from the image carrier after the completion of the replacement work of the image carrier. In such a case, the image forming apparatus may fail to form a normal image, or may fail to normally feed a recording medium.

Image forming apparatus having transfer belt contact and separating mechanism interfering with removable unit


An apparatus for controlling temperature of a process chamber which includes a plurality of heating elements mounted juxtaposed to a cylindrical chamber sidewall of the process chamber for heating the chamber, and a plurality of thermal sensors with one mounted juxtaposed to each of the plurality of heating elements such that the temperature of the chamber cavity can be more uniformly controlled. The method may be carried out by first forming a substantially air-tight chamber cavity by a cylindrical chamber sidewall, a top enclosure and a bottom enclosure, and then positioning a plurality of heating elements juxtaposed to and surrounds the cylindrical chamber sidewall and then mounting a plurality of thermal sensors to the plurality of heating elements with one sensor juxtaposed to each heating element, and then controlling the temperature of the process chamber by inputting signals from the plurality of thermal sensors into a controller and then outputting signals to the plurality of heating elements.

In the continuing miniaturization of semiconductor devices, one of the keys to shrinking device geometries is the ability to construct very dense contact or interconnect structures such as that used in a multi-level metallization schemes. The critical processing step involves etching the contacts and interconnects to a dimension as small as 0.35 .mu.m or even 0.25 .mu.m in diameter in applications for a 64 or 256 megabit DRAMs or other high-density logic devices. To fully implement the process, high selectivity of oxide to the underlying polysilicon or silicide is a key requirement. A high-density plasma etch process utilizing fluorine chemistry is ideal for the high selectivity etch process. A suitable equipment to be used for the process is supplied by the Applied Materials, Inc. of Santa Clara, Calif. Under the tradename of Centura Omega.TM. dielectric etch system. For instance, an oxide etch process can be performed in such an equipment by etching 8,000 .ANG. to 12,000 .ANG. of doped oxide down to a nitride layer. The etch step uses a well-characterized C.sub.2 F.sub.6 or C.sub.3 F.sub.8 chemistry to etch the oxide and stopping at the nitride layer. In order to avoid or to minimize a polymer film deposition during the etch process, a high density plasma source powered by a 2 MHZ RF signal is used. The source generates an ion density of about 1.times.10.sup.12 cm.sup.-3. Free fluorine atoms are removed or scavenged from the reaction chamber through the use of a heated silicon top plate.
Referring initially to FIG. 1, a cross-sectional view is shown of a typical plasma etch reactor equipped with a silicon ceiling as a scavenging surface. The silicon ceiling is a source of silicon atoms which scavenge fluorine out of the plasma to thereby provide a desired carbon-to-fluorine ratio forming a carbon-rich polymer impervious to the fluorine in the plasma over the non-oxide (i.e., polysilicon or silicon nitride) film. In a typical etching process, a reactant gas such as C.sub.2 F.sub.6 is excited sufficiently to generate a plasma inside the reactor chamber and to produce ions and free radicals of F and CF.sub.3. The F radicals etch any silicon dioxide film on the wafer, while carbon and fluorine atoms or ions in the plasma combine on the wafer surface to form a polymer.
The polymer disassociates when formed on silicon dioxide surfaces due to the effect of oxygen freed from the silicon dioxide film during the etch process, and due to the effect of fluorine in the plasma. However, when polymer is formed on non-oxide film (i.e., polysilicon or silicon nitride), the polymer accumulates due to the lack of oxygen in the underlying non-oxide film. This formation inhibits etching of the underlying non-oxide film and thereby provides a pronounced etch selectivity of the oxide film over the non-oxide film. The selectivity is of great importance when etching vias through a silicon dioxide layer overlying a non-oxide layer which is not to be etched. The selectively is limited if the polymer formed over the polysilicon layer contains more than 40% fluorine by weight, because such polymers are susceptible to being attacked by fluorine in the plasma, and therefore provide only limited protection to the underlying polysilicon layer.
FIG. 1 shows an inductively coupled plasma etch reactor of the type generally used. The reactor includes a vacuum chamber 10 enclosed by a cylindrical quartz sidewall 12 and a bottom 14 including a cathode assembly on which a silicon wafer 16 is held by a retractable annular holder 18 on a pedestal 19. The ceiling 20 is made of crystalline silicon and heated by an overlying heating element 22 connected to a temperature controller (not shown). A cylindrical aluminum top wall 24 rests on the quartz sidewall 12 and supports an overlying cooling element 26 in which coolant is circulated through water jacket 28 as shown in FIG. 2. This arrangement cools the quartz sidewall 12 through the aluminum cylindrical top wall 24.
A helical cylindrical antenna coil 30 is wrapped around the cylindrical quartz sidewall 12 and is connected to an RF energy source 32 to inductively couple energy to the plasma in the chamber 10. A ceramic cylindrical cover 34 made of materials such as Al.sub.2 O.sub.3 or Si.sub.2 N.sub.4 surrounds the antenna coil 30.
A gate valve-vacuum pump assembly 36 draws gas from the chamber 10 through an opening in the chamber body 38 to maintain a vacuum in the chamber 10 through an opening in the chamber body 38 to maintain a vacuum in the chamber 10 determined by a pressure control device 40. A gas feed 42 feeds reactant gases such as C.sub.2 F.sub.6 into the chamber 10.
In order to maintain the temperature of the interior surface of the quartz sidewall 12 well above 170.degree. C. a single heating element (not shown) rests in the interior of the ceramic cover 34 near the bottom of the quartz sidewall 12 and is connected to an electrical source (not shown). The temperature of the heating element is monitored by a thermal sensor 28 which feeds a signal to a controller (not shown).
The temperature of the silicon ceiling 20 determines the rate at which silicon atoms scavenge the plasma within the chamber 10 and therefore affects the carbon-to-flourine plasma ratio providing a polymer carbon content greater than 60% by weight. Such temperature control of the ceiling 20 is provided by a controller governing the ceiling heat source in accordance with a signal received from a thermocouple 44 attached to the silicon ceiling 20. Heat conduction to the silicon ceiling 20 is set by a suitable air gap between the heater 22 and the ceiling 20.
During an etching process, the RF power source 32 used is in the range of 2,000-3,000 watts at about 2 MHz. The bias RF power source 46 connected to the pedestal 19 is in the range of 500-1500 watts at 1.8 MHZ depending on the size of the wafer 16. The silicon ceiling temperature is in the range of 200.degree.-300.degree. C., and is normally set at approximately 260.degree. C. The quartz sidewall interior surface temperature is in the range of between 170.degree. C. and 230.degree. C, and is normally set at 220.degree. C. The C.sub.2 F.sub.6 gas flow rate is between 20-50 standard cubic centimeters per minute and the chamber pressure is between 1-10 millitorr.
In a typical etching process for oxide films, a high density, low pressure plasma is used. The chemistry involved is the dissociation of C.sub.2 F.sub.6 into components of CF.sub.2 F and C. The CF.sub.2 is the active etching component of the gas, while F and C forms a fluorocarbon polymer that deposits on any surface that is relatively cool (i.e., at a temperature of 100.degree. C. or below).
A cross-sectional view of the quartz sidewall 12 which contains the chamber cavity 10 for a conventional plasma etch chamber is shown in FIG. 2. A heating element 50 is contained in the interior of a ceramic cover (not shown) in-between the quartz sidewall 12 and the helical cylindrical antenna 30. In a conventional etcher, or for most other semiconductor process chambers, a single heating element 50 is utilized with its temperature monitored by a single thermal sensor 28. In the chamber cavity 10, processing difficulties frequently occur due to a poor temperature uniformity achieved across the chamber cavity. For instance, during a plasma etching process, where the quartz sidewall 12 is maintained at a temperature well above 170.degree. C. and normally at a temperature of about 220.degree. C. a temperature variation as high as 30.degree. C. within the chamber cavity 10 is observed. This creates a serious problem in a plasma etching process resulting in a large variance in the etch rates at different locations in the cavity. A semiconductor substrate that has a non-uniform top layer is frequently obtained after the etching process. The conventional heating method of utilizing a single heating element monitored by a single thermal sensor is therefore inadequate for achieving a uniform process environment during a semiconductor process, regardless an etching, a deposition or any other process.
It is therefore an object of the present invention to provide an apparatus for controlling temperature of a process chamber in semiconductor processing that does not have the drawbacks or shortcomings of the conventional apparatus.
It is another object of the present invention to provide a process chamber for a semiconductor substrate that contains a cylindrical chamber sidewall which is heated by a plurality of heating elements.
It is a further object of the present invention to provide a process chamber for a semiconductor substrate that is equipped with a cylindrical chamber sidewall heated by at least two heating elements and monitored by at least two thermal sensors.
It is another further object of the present invention to provide a process chamber for a semiconductor substrate that is equipped with a cylindrical chamber sidewall fabricated in quartz and heated by a plurality of heating elements.
It is still another object of the present invention to provide a process chamber for a semiconductor substrate that is equipped with a cylindrical shaped quartz sidewall heated by a plurality of heating elements and energized by a helical cylindrical antenna coil.
It is yet another object of the present invention to provide a method for controlling temperature of a process chamber including the step of mounting a plurality of heating elements juxtaposed to and surround a cylindrical chamber sidewall.
It is still another further object of the present invention to provide a method for controlling temperature of a process chamber including the steps of positioning a plurality of heating elements juxtaposed to and surround a cylindrical chamber sidewall, and mounting a plurality of thermal sensors to the plurality of heating elements with one thermal sensor juxtaposed to each heating element.
It is yet another further object of the present invention to provide a plasma etch chamber which includes a cylindrical chamber sidewall, a plurality of heating elements mounted juxtaposed to the sidewall, a plurality of thermal sensors with one mounted to each of the plurality of heating elements, and a temperature controller for controlling temperature of the chamber cavity.

Apparatus and method for controlling temperature of a chamber

Taiwan Semiconductor Manufacturing Co., Ltd


A package for mounting a light emitting element includes: a first lead electrode having, in a plan view, a first region, a second region surrounding a periphery of the first region having a width of 110 μm or more and a thickness greater than that of the first region, and a third region partially surrounding a periphery of the second region and having a thickness smaller than that of the second region; a second lead electrode spaced apart from the first lead electrode; and a resin molded body fixing a portion of each of the first and second lead electrodes. A portion of each of the first and second lead electrodes and a portion of the resin molded body exposed therebetween form a bottom surface of a recess.

1. Technical Field
The present disclosure relates to a package, a light emitting device, and methods of manufacturing the package and the light emitting device.
2. Description of the Related Art
Various types of light emitting devices using a light emitting element and methods of manufacturing the same have been developed. For example, JP 2014-29995 A discloses a light emitting device having a linear protrusion at a lead frame, and a method of manufacturing the light emitting device. Also for example, JP 2004-274027 A and JP 2005-353914 A each disclose a light emitting device in which a portion of a lead frame forming a bottom surface of a recess is recessed to place a light emitting element therein, and a method of manufacturing the light emitting device.
Meanwhile, a method of manufacturing a light emitting diode (hereinafter referred to as an "LED") includes molding a package, and an LED is manufactured through the molding step. In manufacturing an LED, transfer molding has been typically employed, in which a lead frame is set in a mold and liquid resin is injected. However, with such a method of manufacturing an LED, the resin flows into a gap between the lead frame and the mold, which may result in the generation of resin burrs. Such resin burrs may cause a bonding failure of LED elements and/or wires, so the burrs must be removed. Accordingly, in conventional manufacturing of an LED, the molding is always followed by removing burrs.
In such a method of manufacturing an LED, examples of ways to prevent generation of resin burrsinclude optimizing conditions in the molding, increasing the pressing force of the mold, reducing the number of LEDs molded with a single lead frame, increasing the viscosity of resin to reduce flowability or the like.
Further, JP2014-29995 A discloses that, in a lead frame provided with a plating layer on its surface, burrs can be reduced by allowing the plating layer to rise and protrude at the border of a portion where a metal portion is desired to be exposed (a LED mounting portion, a wire bonding portion).
The mold disclosed in JP 2014-29995 A is provided with a projection having a shape corresponding to a recess of a package. Accordingly, the mold has the following structure. When the lead frame is clamped, the projection of the mold abuts and is pressed against a linear protrusion formed by plating raised at the boundary of the LED mounting portion or the like. Thus, entry of resin which will become burrs is prevented.
However, in the method of manufacturing disclosed in JP 2014-29995 A, the width of the linear protrusion is small, so that formation of the protrusion on the lead frame is difficult.
In the light emitting device and the method of manufacturing the same disclosed in JP 2004-274027 A and JP 2005-353914 A, in order to facilitate control of the directivity of light and to improve the light-extracting efficiency, a portion of the lead frame forming the bottom surface of the recess is further recessed. Thus, neither of these disclosures discloses preventing the generation of burrs. Accordingly, the methods disclosed in JP 2004-274027 A and JP 2005-353914 A are insufficient to prevent generation of burrs.

Light emitting device package having lead electrode with varying thickness


A stabilizer composition for use in halogen-containing polymers comprising hydrotalcite and a molecular-sieve zeolite comprising a Group IA or IIA alumino-silicate.

1. Field of the Invention
The present invention relates to stabilizer compositions for halogen containing polymers, particularly polymers of vinyl chloride, and to polymeric formulations containing such compositions.
2. Background of the Invention
Halogen-containing polymers, more general by vinyl chloride polymers (PVC), are commonly used for wire insulation and cable jacketing purposes, particularly for use in office buildings and the like. In order to impart thermal stability to PVC insulation and/or cable jacketing, various thermal stabilizers are incorporated. In particular, lead salts have been used as thermal stabilizers in such PVC formulations. Along with providing heat stability, lead based stabilizers generally impart good electrical insulating properties to the polymeric formulation.
Because of increasing health and environmental concerns, attempts have been made to replace the lead based thermal stabilizers in PVC and other halogen-containing polymeric compositions. For example, a common PVC heat stabilizer comprises a mixture of antimony and tin salts. While these stabilizers are preferable to lead based stabilizers from a health and environmental viewpoint, they generally do not provide the electrical insulating properties which can be achieved using lead based thermal stabilizers.
Ideally, a thermal stabilizer for halogen-containing polymeric composition would contain no heavy metal salts, e.g. lead salts, but would impart thermal stability and electrical insulating properties equivalent or superior to those achieved with lead salts.

Stabilizer compositions for halogen-containing polymers and polymer compositions containing same


Methods and apparatus, including computer program products, implement techniques for representing control functions in a user application. A group of control palettes is provided in an application window of the user application. A user input associates the group of control palettes with a location within a region extending along one or more borders of a user interface. A stashed palette group is generated in response to the user input. The stashed palette group has an active state and an inactive state. The active state includes an expanded view that includes a representation of control data and/or control functions of one or more of the control palettes, arranged in a floating, non-modal window that covers a portion of the user interface in an area proximate to the location. The inactive state includes a collapsed view of the group arranged along the border in an area proximate to the location.

The present invention relates to presenting computer program application controls in a user interface.
Many conventional computer program applications provide for user interaction through a graphical user interface. To make the application's controls easily accessible to users, such applications typically provide a number of different user interface elements, such as toolbars, pull-down menus, dialog boxes, and floating palettes, with which the user can invoke commands, retrieve operations, and the like.
Toolbars typically feature an arrangement of interactive buttons that can be selected to invoke particular operations, and are typically arranged along an edge of an application window of the user interface. Pull-down menus are typically lists of commands that can be hidden and activated or pulled down with a pointing or cursor control device, such as a mouse or trackball, or a keyboard command. These single-word commands take up very little of the screen because the pull-down menu, in its collapsed state, has a very compact form, such as a single command word. Dialog boxes are interface elements that are typically composed of rectangular regions that appear outside of the document window. Dialog boxes are typically "modal" elements, which means that while a dialog box is active, action within the document is usually halted while the user is requested to select one or more of a number of options identified within the dialog box. The dialog box is then dismissed and disappears, and the document is updated based upon the selection that the user made from the dialog box.
By contrast, a floating palette (or simply a "palette" or "control palette") is a window that is subsidiary to the main application window and contains commands or tools that are used in an interactive fashion. For the purposes of this specification, a floating palette is a window that "floats" above any open document window, meaning that it remains "on top" of the document window, even when the palette is not the current focus. It should be noted that a palette is considered to be "on top" of an underlying document window if it appears directly over all or a portion of the underlying document window, or, if it does not appear over any portion of the document window (for example, if it appears to the side of a document window), if it would appear on top of the document window if either the palette or document window were moved so that the two overlap. As opposed to dialog boxes, floating palettes are "non-modal". This means that, unlike in modal elements, actions occurring within the document are not halted while the palettes are accessed by the user. Accordingly, floating palettes are most useful for holding tools and commands that a user needs to access interactively at the same time with the document itself.
Conventional applications often provide for a number of different control palettes, and often palettes provide the most convenient, or even the only, way to access some control features of the application. Palettes can sometimes be grouped or docked to provide for convenient access to functions that are frequently used together, such as in a workflow. Leaving multiple palettes or palette groups open on the desktop can consume valuable screen real estate, which can result in obscuring portions of a document being manipulated in the application. To avoid this, users can close any palettes or groups that are not being actively used, but to reopen those palettes or groups can require the user to invoke a sometimes complicated series of keystrokes, mouse movements or commands to reopen and reactivate the palettes if their functionality is later desired.


A driving device includes an electro-mechanical transducer having first and second end portions opposite to each other in an expansion/contraction direction, a stationary member coupled to the first end portion of the electro-mechanical transducer, a vibration friction portion coupled to the second end portion of the electro-mechanical transducer, and a rod-shaped moving portion frictionally coupled to the vibration friction portion, whereby moving the moving portion in the expansion/contraction direction of the electro-mechanical transducer. The vibration friction portion is made of a material having a vibration transfer rate of 4900 meters/second or more. The moving portion is made of a material which has a vibration transfer rate of 4900 meters/second or more and which is different from that of the vibration friction portion.

This invention relates to a driving device (a linear actuator) and, in; particular, to a driving device where an electro-mechanical transducer such a piezoelectric element is used as a driving source of the driving device (the linear actuator).
Previously, linear actuators (driving devices) using electro-mechanical transducers such as piezoelectric elements, electrostrictive elements, magnetostrictive elements, or the like are used as auto-focus actuators or zoom actuators for use in cameras.
By way of illustration, Japanese Patent No. 2633066 (JP-B 2633066) (which will be also called a first patent document), which corresponds to U.S. Pat. No. 5,225,941, discloses a driving device comprising a driving rod frictionally engaged with a lens barrel, a piezoelectric element disposed in contact with the driving rod, and a leaf spring for bringing the driving rod into frictional engagement with the lens barrel. That is, the driving rod is bonded to an end of the piezoelectric element in an expansion direction. The lens barrel is movably supported to the driving rod. The leaf spring produces friction between the driving rod and the lens barrel. In the driving device disclosed in JP-B 2633066, a voltage is applied to the piezoelectric element so as to make a speed of expansion of the piezoelectric element different from a speed of contraction thereof.
In addition, Japanese Patent No. 3218851 (JP-B 3218851) (which will be also called a second patent document), which corresponds to U.S. Pat. No. 5,589,723, discloses a driving apparatus comprising a piezoelectric element, a driving member (a driving shaft), coupled to the piezoelectric element, for extending in an expansion direction of the piezoelectric element, and a driven member (a moving member, a lens barrel) having a friction member frictionally coupled to the driving member (the driving shaft). The driving apparatus in JP-B 3218851 drives the lens barrel by devising a driving signal applied to the piezoelectric element. Japanese Patent No. 3180557 (JP-B 3180557) (which will be also called a third patent document), which corresponds also to U.S. Pat. No. 5,589,723, discloses a driving apparatus including the friction member composed of a metal and the driving member made of a fiber-reinforced resin composite.
Japanese Unexamined Patent Application Publication No. 2006-54979 (JP-A 2006-54979) (which will be also called a fourth patent document) discloses an actuator which is capable of moving a driven member with stability and with precision. The actuator disclosed in JP-A 2006-54979 comprises a first piezoelectric element, a diving member mounted to the first piezoelectric element, a driven member which is frictionally coupled to the driving member and which extends in a driving direction, and a second piezoelectric element for engaging the driving member with the driven member and for releasing a friction engagement between the driving member and the driven member. Specifically, the actuator disclosed in JP-A 2006-54979 comprises a pair of first piezoelectric elements for driving, a second piezoelectric element for engagement, a pair of driving members, and a pressure spring. The pair of first piezoelectric elements and the pair of driving members are disposed at both sides with the driven member sandwiched between them. The pair of driving members have a distance which is expanded or narrowed by the second piezoelectric element. By the second piezoelectric element, the friction engagement between the pair of the driving members and the driven member is ensured or released.
Japanese Unexamined Patent Application Publication No. H9-191665 (JP-A 9-191665) (which will be also called a fifth patent document), which corresponds to U.S. Pat. No. 5,890,391, discloses a linear drive mechanism using an electromechanical conversion element which is insensitive to elastic deformation of a constituent member. The linear driving mechanism disclosed in JP-A 9-191665 comprises the electromechanical conversion element, a working member which is fixedly connected to the electromechanical conversion element and which displaces with the electromechanical conversion element, a driving member frictionally coupled to the working member, a driven member coupled to the driving member, and a driving pulse generating arrangement for causing expansion/contraction displacement to the electromechanical conversion element.
Japanese Unexamined Patent Application Publication No. 2006-5998 (JP-A 2006-5998) (which will be also called a sixth patent document) discloses a liner actuator in which optimum surface roughness is specifically defined in a contact state of a frictionally coupled portion between a transfer member (a vibration friction portion) for transferring vibration of a piezoelectric element and a moving member (a moving portion) which is frictionally coupled to the transfer member (the vibration friction portion). In JP-A 2006-5998, a rod made of carbon is used as the transfer member and a combination of a metal slider and a cap which sandwich the rod is used as the moving member.
Japanese Unexamined Patent Application Publication No. H10-337057 (JP-A 10-337057) (which will be also called a seventh patent document), which corresponds to U.S. Pat. No. 6,188,161, discloses a driving apparatus capable of high speed driving in a high frequency range. In the driving apparatus disclosed in JP-A 10-337057, a movable member is movably supported by a fixed shaft (a driving shaft). Aligned in the direction of the fixed shaft, a piezoelectric element has one expansion end which is connected to one end of the movable member. The piezoelectric element has another expansion end which is connected to a driving friction member. The driving friction member comprises a main body that is connected to the piezoelectric element and a pair of semi-cylindrical protrusions that protrude toward the fixed shaft from a side of the main body. The pair of protrusions elastically grasp the fixed shaft from both above and below, and are in friction contact with the fixed shaft. The driving friction member is made lightweight, highly elastic, highly movable and very hard by using an aluminum alloy treated with anode oxide coating. JP-A 10-337057 neither discloses nor teaches a material of the fixed shaft (the driving shaft).
Japanese Unexamined Patent Application Publication No. H7-49442 (JP-A 7-49442) (which will be also called an eighth patent document) discloses a driving device comprising a driving member vibrating in an axial direction and a driven member making friction contact with the driving member. In the driving device disclosed in JP-A 7-49442, the driving member and the driven member are formed from frictional anisotropic materials in which the frictional coefficient between the driving member and the driven member is differed in positive and reversed vibrating direction of the driving member.
Furthermore, Japanese Patent No. 3171000 (JP-B 3171000) (which will be also called a ninth patent document), which corresponds also to U.S. Pat. No. 5,589,723, discloses a driving apparatus which is capable of realizing high speed movement. The driving apparatus disclosed in JP-B 3171000 comprises a support member (a stationary member), an electro-mechanical transducer, a driving member (a vibration friction portion), a barrel (a moving member), and a friction adding member (a plate spring). The electro-mechanical transducer has an end in an expansion/contraction direction that is fixed to the stationary member. The electro-mechanical transducer is applied with a voltage so that the electro-mechanical transducer expands and contracts at different speeds on expanding and on contracting, respectively. The driving member (the vibration friction portion) is connected to another end of the electro-mechanical transducer and is supported so as to move in the expansion/contraction direction of the electro-mechanical transducer. The moving member is frictionally engaged with the driving member and is supported so as to move in the expansion/contraction direction of the electro-mechanical transducer. The friction adding member provides a friction force between the driving member and the moving member. The driving member and the moving member are set to generate sliding therebetween even when the electro-mechanical transducer is expanded and contacted. However, JP-B 3171000 neither discloses nor teaches specific materials of the driving member (the vibration friction member) and the moving member.
There are problems in the above-mentioned first through forth patent documents as follows.
In the driving device disclosed in the first patent document, inasmuch as the lens holder (the driven member, the moving portion) is movably supported to the guide bar (the driving member, the vibration friction portion) bonded to the piezoelectric element, the guide bar (the driving member, the vibration friction portion) has a length longer than that of the lens holder (the driven member, the moving portion) and the guide bar (the driving member, the vibration portion) is easy to produce an inclination caused by a reciprocating motion. In addition, the longer a moving distance of the lens holder (the driven member, the moving portion), the longer the guide bar (the driving member, the vibration friction member) and it results in easily producing an unnecessary vibration mode. Furthermore, inasmuch as the friction engagement portion lies on an extension of a coupling portion between the piezoelectric element and the guide bar (the driving member, the vibration friction member), it counts against a reduction in profile thereof.
In also the driving apparatus disclosed in the second patent document, inasmuch as the driving shaft (the driving member, the vibration friction portion) extends in an expansion/contraction direction of the electro-mechanical transducer, the driving shaft (the driving member, the vibration friction portion) has a length longer than that of the a zoom lens barrel (the driven member, the moving portion) and the driving shaft (the driving member, the vibration friction portion) is easy to produce an inclination caused by a reciprocating motion. In addition, the longer a moving distance of the zoom lens barrel (the driven member, the moving portion), the longer the driving shaft (the driving member, the vibration friction portion) and it results in easily producing an unnecessary vibration mode. Furthermore, inasmuch as the friction engagement portion lies on an extension of a coupling portion between the electro-mechanical transducer and the driving shaft (the driving member, the vibration friction member), it counts against a reduction in profile thereof. In addition, inasmuch as the driving apparatus has structure where the zoom lens barrel (the driven member, the moving portion) is cantilevered by the driving shaft (the driving member, the vibration friction portion), it is impossible to mechanically move a large weight object such as the lens.
The third patent document may just disclose the driving apparatus where the driving shaft (the driving member, the vibration friction portion) is made of the fiber-reinforced resin composite and has a basic structure which is similar to that illustrated in the second patent document. It has therefore disadvantage which is similar to that of the second patent document.
Although the driving member (the vibration friction portion) has a length which is shorter than that of the driven member (the moving portion) in the actuator disclosed in the fourth patent document, the actuator disclosed in the fourth patent document is disadvantageous in that it is complicated in structure and it is impossible to reduce a size thereof because it comprises a plurality of piezoelectric elements.
On the other hand, the fifth patent document discloses the linear drive mechanism where the moving member (the moving portion) has a rod shape and the working member (a vibration friction portion) has a complicated shape. Incidentally, in order to improve moving efficiency of the moving portion due to vibration displacements of the vibration friction portion that are generated by the electro-mechanical transducer, it is necessary to adjust a coefficient of kinetic friction and a coefficient of static friction between the vibration friction portion and the moving portion to optimum values or conditions. For this purpose, it is necessary to select suitable materials for the vibration friction portion and the moving portion. However, the fifth patent document neither discloses nor teaches the materials of the vibration friction portion and the moving portion.
The sixth patent document defines the surface roughness of the vibration friction portion and the moving portion which are frictionally coupled to each other. However, in the manner which is described above, in order to improve the moving efficiency of the moving portion due to vibration displacements of the vibration friction portion generated by the electro-mechanical transducer, it is necessary to adjust the coefficient of kinetic friction and the coefficient of static friction between the vibration friction portion and the moving portion to optimum values or conditions. The coefficient of kinetic friction and the coefficient of static friction have values which change dependent not only on the surface roughness of the vibration friction portion and the moving portion but also on the hardness and density of materials of both.
Although the seventh patent document may describe the material of the driving friction member, but the seventh patent document neither discloses nor teaches the material of the fixed shaft (the driving shaft). The eighth patent document merely discloses the driving device comprising the driving member and the driven member which are formed from frictional anisotropic materials. The ninth patent document neither discloses nor teaches specific materials of the driving member (the vibration friction member) and the moving member.
At any rate, although it is necessary for the driving device to transfer vibrations generated by the electro-mechanical transducer to the vibration friction portion with a high degree of efficiency, any of the first through the neigh patent documents neither discloses nor teaches the materials of the vibration friction portion and the moving portion which are suitable to realize this.

Driving device capable of transferring vibrations generated by an electro-mechanical transducer to a vibration friction portion with a high degree of efficiency


A driving module for a liquid crystal display device with a dual-gate structure includes a data line signal processing unit, for generating a plurality of data driving signals, and a control unit, for shifting a common voltage and the plurality of data driving signals by a specific period relative to a horizontal synchronization signal. The common voltage is an AC common voltage.

1. Field of the Invention
The present invention relates to a driving module, driving method, and liquid crystal display (LCD) device, and more particularly, to driving module, driving method, and liquid crystal display (LCD) device capable of achieving a dot inversion driving effect without changing the conventional structure and line inversion operations via shifting source voltages and a common voltage by half a horizontal synchronization signal cycle.
2. Description of the Prior Art
An LCD device utilizes a source driver and a gate driver to drive pixels on a panel to display images. Since the cost of a source driver is higher than that of a gate driver and the amount of circuitry of source driver is greater than that of a gate driver (under the situation of 480×272 pixels, since each pixel includes a red subpixel, a green subpixel, and a blue subpixel, circuitry of the source driver corresponding to 1440 data lines and circuitry of the gate driver corresponding to 272 scan lines are required), a dual gate structure is thus developed in order to reduce the amount of source drivers. In short, for the same amount of pixels, the dual gate structure has half as many data lines, and twice as many scan lines, in order to reduce the cost.
In order to avoid repeatedly driving liquid crystal molecules with voltages having the same polarity (positive or negative), thereby reducing polarization or refraction properties of the liquid crystal molecules that will deteriorate image quality, the liquid crystal molecules need to be alternately driven by positive and negative voltages, e.g. line inversion. In other words, an LCD device includes a glass substrate with a common voltage and another glass substrate with a driving circuit and liquid crystal molecules in between, and thus when the LCD device is driven in line inversion by an alternating common voltage (between −5V and 5V for low voltage driving), the alternating common voltage and a source voltage are applied to subpixels to generate a voltage difference, i.e. the source voltage minus the common voltage, to alternately drive the liquid crystal molecules with positive and negative voltage.
Please refer to FIG. 1, which is a schematic diagram of an LCD device 10 with a dual-gate structure according to the prior art. For clear illustration, the LCD device 10 only includes a source driver 100, a gate driver 102, a timing controller 104, data lines S1-Sm, scan lines G1-Gn and a pixel matrix Mat. The timing controller 104 utilizes a horizontal synchronization signal Hsync and an output enable signal Ena to control the source driver 100 and the gate driver 102, respectively, to generate data driving signals Sig_S1-Sig_Sm and gate driving signals Sig_G1-Sig_Gn, so as to charge the pixel matrix Mat. In the pixel matrix Mat, which is a dual-gate structure, each pixel includes a red subpixel RS, a green subpixel GS and a blue subpixel BS, and each subpixel includes a transistor and a capacitor, which are denoted by blocks for simplicity. In the view of columns, subpixels of every two subpixel columns are controlled by a same data line. For example, the red subpixel column RS1˜RSn and the green subpixel column GS1˜GSn are controlled by the data line S1, the blue subpixel column BS1˜BSn and the red subpixel column RS1′˜RSn′ are controlled by the data line S2, and the green subpixel column GS1′˜GSn′ and the blue subpixel column BS1′˜BSn′ are controlled by the data line S3, and so on. In the view of rows, subpixels of each row are controlled by two adjacent scan lines. For example, in a row Row_1, the red pixel RS1, the blue pixel BS1 and the green pixel GS1′ are controlled by the scan line G1, and the green pixel GS1, the red pixel RS1′ and the blue pixel BS1′ are controlled by the scan line G2. Other rows Row_2, Row_3 . . . Row_n are arranged in the same way.
Please refer to FIG. 2A to FIG. 2C. FIG. 2A is a schematic diagram of driving the pixel matrix Mat of FIG. 1 in line inversion with an alternating common voltage, and FIG. 2B and FIG. 2C are schematic diagrams of polarities of subpixels of the pixel matrix Mat of FIG. 2A in frames Fn, Fn+1, respectively. The following description utilizes FIG. 2A to illustrate operations of the red subpixel column RS1˜RSn and the green subpixel column GS1˜GSn corresponding to the data line S1. In detail, in a horizontal synchronization signal cycle Line2, the scan lines G1, G2 are sequentially turned on in periods Tgo, Tge, respectively, such that a source voltage Vs corresponding to the data driving signal Sig_S1 can be applied to the subpixels RS1, GS1 corresponding to the scan lines G1, G2 in periods Tso, Tse, respectively, wherein the periods Tso, Tse are half the horizontal synchronization signal cycle Line2. Since level changes of the source voltage Vs and a common voltage Vcom are synchronized with the horizontal synchronization signal Hsync, polarities of a voltage difference of the source voltage Vs minus the common voltage Vcom for charging the subpixels RS1, GS1 are positive in a frame Fn, and negative in a frame Fn+1. Similarly, in a horizontal synchronization signal cycle Line3, the subpixels RS2, GS2 corresponding to the scan lines G3, G4 are charged with negative polarities in the frame Fn, and are charged with positive polarities in the frame Fn+1. By the same token, polarities of other subpixels of the red subpixel column RS1˜RSn and the green subpixel column GS1˜GSn and polarities of subpixels of subpixel columns corresponding to other data lines can be derived. In such a situation, as shown in FIG. 2B and FIG. 2C, polarities of subpixels in a same row and alternating rows are the same, e.g. the row Row_1 and the row Row_3, the row Row_2 and the row Row_4, and so on, which achieves the effect of line inversion.
However, when driving the dual-gate structure in line inversion, the polarities of subpixels in the alternating rows are the same, which causes lateral crosstalk between subpixels. For example, when an image is meant to show black in the center area and grey in other areas, the left and right parts relative to the center area are lighter due to the lateral crosstalk between subpixels. Thus, there is a need for improvement.

Driving method, driving module and liquid crystal display device for achieving dot inversion


Embodiments of the present invention are directed to a method and apparatus for safety protection control of temporary roof support. In one embodiment, a temporary roof support has a load sensing member. In another embodiment, a beam structure of temporary roof support is supported by a load sensing pin. Strain gages are installed within the pin to measure the load placed upon the pin. An unusually high load being sensed by the pin indicates that the roof has fractured and the temporary roof support is supporting loose rock. In one embodiment, when an unusually high load is measured at the pin, the temporary roof support controls at the front of the machine are disabled. A second set of remotely located temporary roof support controls remain operative. In one embodiment, the second set of controls is located at the rear of the machine.

1. Field of the Invention
The present invention relates to the field of load-bearing hydraulics, and in particular to a method and apparatus for safety protection control of temporary roof support.
2. Background Art
In mining operations, roof fall situations are of pressing concern. Safety precautions are taken to prevent personnel being injured by roof falls, including adding support structures to the roof bolter equipment. However, prior art methods of adding structural support remain dangerous for those installing the support. This problem can be better understood with a review of temporary roof supports.
Temporary Roof Supports
A temporary roof support is used to support the roof of an excavated location during installation of permanent roof support (e.g., operation of roof bolters). In one common arrangement, a dual boom roof bolter has two operators and two sets of controls for installing roof bolts. Typically, each operator is responsible for bolting one half of an entry way. Frequently, one operator also has controls on the boom to lower and raise a temporary roof support as well as to move the machine at a reduced rate of speed. Such controls are used in repositioning the machine after each row of bolts across an entry is installed.
However, under certain roof conditions, the roof may fracture while temporary roof support is supporting the roof. An operator may or may not be aware that such a fracture has occurred. During typical operation of roof bolters, the roof bolts are installed at approximately four foot intervals. Thus a large amount of rock may be broken loose between installed roof bolts and be supported solely by the temporary roof support.
Loose rock causes at least three potential hazards. First, the controls of the temporary roof support are located near the front of the roof bolter. Thus, an operator is exposed to falling rock when the temporary roof support is released. Second, a temporary roof support is supported by hydraulic cylinders with load holding valves. The speed of the decent of the temporary roof support is dependent only upon the load applied and the restrictions in the hydraulic circuit. Thus, the temporary roof support may descend at a rate that is hazardous to the operator, even though the loose rock is not free-falling. Additionally, the strain on the hydraulic circuit resulting from the rapid decent may cause damage to the temporary roof support.

Method and apparatus for safety protection of temporary roof support


This invention describes an improved lubricating system for polyvinylchloride and other plastic. In particular the present invention describes compositions having excellent metal release properties for the plastics industry.

1. Field of this Invention
This invention relates to polyvinylchloride products and in particular, lubricants for polyvinyl chloride products.
Polyvinylchloride articles are useful for a number of purposes ranging from highly flexible inductile materials to those which are quite rigid. This invention is particularly concerned with the manufacture of rigid polyvinylchloride articles and particular to a novel lubricant system for rigid polyvinylchloride articles.
It is generally known that polyvinylchloride will adhere to the sides of the equipment in which it is processed. Typically, polyvinylchloride is mixed with other useful ingredients including lubricants and is masticated in an extruder. Twin screw extruders are often used with the pellets of polyvinylchloride being added together with the other ingredients at one end of the extruder. The extruder, by crushing and pushing the polyvinylchloride articles together, forms a liquid melt.
The molten-state polyvinylchloride is then pushed through the extruder and eventually extruded through a die. At any point in the processing where the polyvinylchloride contacts metal the possibility of adhesion occurs. In a free-flowing process the polyvinylchloride moves through the extruder and is easily extruded through the die. However, when the process is interrupted or the flow is stopped in the extruder the possibility occurs for the polyvinylchloride to adhere. Even without the adhesion in the extruder it is possible for the polyvinylchloride to resist flow through contact with the extruder walls.
The contact of the polyvinylchloride with the extruder walls requires greater physical energy to move the polyvinylchloride through the extruder. As the extruder is typically connected to a constant rpm motor the flow of polyvinylchloride should be smooth through the extruder. If the flow of the polyvinylchloride is restricted by adhesion to the walls of the extruder the motor may become overworked. At the very least, greater energy expenditures are observed when lubrication is not properly utilized to continue the flow of the polyvinylchloride through the extruder.
There are attendant difficulties in utilizing polyvinylchloride lubricants. These difficulties involve adverse consequences to the polyvinylchloride articles. The present invention exhibits both internal and external polyvinylchloride lubricating properties. An internal lubricant for polyvinylchloride is one which assists in the movement of the molecules of polyvinylchloride over one another to ensure that an even melt is achieved in the extruder. The adverse consequences which can result from utilizing an improper internal lubricant are primarily concerned with the heat distortion caused by the flexibility of the article which in turn is caused by the lubricant.
External lubricants are those which primarily contact the walls of the extruder and of the die. The purpose of the external lubricant is to facilitate the passage of the polyvinylchloride through the extruder. Ordinarily, the external lubricant is desired to be left on the walls of the extruder or the die and that the external lubricant migrate to the surface of the finished polyvinylchloride article. It is thus possible by correctly choosing an external lubricant to have one which may be cleaned from the finished article so that the article may be painted or otherwise treated.
A lubricant which shows both internal and external lubricating properties for polyvinylchloride is highly desirable as the overall level of additives in the polyvinylchloride may be reduced through the judicious selection of the proper lubricant. First, the cost of the lubricant system for the polyvinylchloride may be reduced and as the external lubricating agents tend to migrate from the polyvinylchloride it is possible to avoid having substantial quantities of internal lubricant remain in the finished polyvinylchloride article. The polyvinylchloride articles with which the invention is concerned are clear articles such as bottles, opaque sheets, and rigid profiles of polyvinylchloride.
2. Description of the Art
Wilson, in U.S. Pat. No. 3,981,838 issued Sep. 21, 1976 describes various tri-carboxylic compounds which may be esterified and utilized in processing plastics. Wilson states that acid numbers under 2.5 are arbitrarily viewed as essentially tri-esters. Wilson further continues to state that acid numbers greater than that would correspond to a decrease in external lubricity.
Worschech in U.S. Pat. 3,875,069 describes lubricants for thermoplastic materials which are (A) mixed esters of aliphatic polyols, dicarboxylic acids and long chained aliphatic monocarboxylic acids, and (B) esters of the group of dicarboxylic acids and long chained aliphatic monofunctional alcohols; esters of long chained aliphatic monofunctional alcohols and long chained aliphatic monocarboxylic acids; and complete or partial esters of aliphatic polyols and long chained aliphatic monocarboxylic acids in a ratio of (A) to (B) of 1:3 to 9:1. The highest acid number mentioned in the Worschech '069 patent is six with the recommendation that there are no free hydroxyl or acid groups in his lubricant molecule.
In U.S. Pat. No. 4,336,176 issued Jun. 22, 1982, to Lindner, there is disclosed manufacture of polyvinylchloride compounds utilizing an organo-tin compound and a partial ester having functionality as both an internal lubricant and a co-stabilizer for the plastic. U.S. Pat. No. 4,425,458 issued Jan. 10, 1984 to Lindner describes the use of polyguerbet alcohol esters as lubricants for polycarbonate. U.S. Pat. No. 4,487,874 issued Dec. 11, 1984 to Lindner discloses polycarbonate lubricants which were formed from the partial esterification of pentaerythritol.
U.S. Pat. No. 4,690,977 to Hosoi et al, issued on Sep. 1, 1987, describes vinylchloride polymers comprising a grafted polymer, a vinylchloride polymer, a rubber copolymer, and a lubrication system which includes a wax lubricant and epoxidized soybean oil. Hosoi et al makes similar disclosures in U.S. Pat. No. 4,645,795 issued Feb. 24, 1987.
Schofield et al in U.S. Pat. No. 4,797,440 issued Jan. 10, 1989 describes a thermoplastic polymeric organic medium in the presence of a lubricant and a processing additive containing a divalent aliphatic radical. The stabilization of polyvinylchloride is taught in U.S. Pat. No. 4,338,226 issued Jul. 6, 1982 to Worschech et al. The stabilization of the vinylchloride polymers is also taught by Crochemore et al in U.S. Pat. No. 4,102,839 issued Jan. 25, 1978. U.S. Pat. No. 3,951,883 issued Apr. 20, 1976 to Ruchlak et al discloses polyvinylchloride molding compositions.
Tenaka et al in U.S. Pat. No. 4,072,657 issued Feb. 7, 1978 discloses synthetic resins which include vinylchloride-vinylacetate copolymers. U.S. Pat. No. 4,392,581 issued Jul. 12, 1983 to Itsubo et al describes vinylchloride resin compositions. U.S. Pat. No. 3,578,621 issued May 11, 1971 to Stapfer describes stearamide waxes which may be utilized for plastic processing.
This invention deals with lubricant additive systems for polyvinylchloride resins which have superior properties with to metal release and having low gloss.
Throughout the specification and claims, percentages and ratios are by weight, temperatures are in degrees Celsius, and pressures are in KPa gauge unless otherwise indicated. To the extent that any of the references cited herein are applicable, they are hereby specifically incorporated by reference. Ranges and ratios given herein may be combined.

Polyvinylchloride processing and compositions using a polyol reacted with a monocarboxylic acid and a dicarboxylic acid


An endplate for an intervertebral prosthesis includes a generally planar base plate, a first elevated region, or dome, within the base plate periphery, and a second elevated region, or dome, within the boundary of the first elevated region. The antero-posterior and side-to-side (medial-lateral) dimensions of the first elevated region are made to be unequal in order to provide resistance to torsional stresses, and the laterally opposite sidewalls of the first elevated region are defined by arcs that terminate in sagittal planes of the endplate, and are symmetrical with respect to a coronal plane of the endplate. A bone rasp and a groove cutter for use in implanting the prosthesis are also provided.

1. Field of the Invention
This invention relates to prostheses for replacing a human intervertebral disc and instruments for implanting such a prosthesis, and more particularly to an endplate for such a prosthesis having a domed surface for contacting an adjacent vertebra in a human spinal motion segment.
2. Background Art
The human spinal column achieves its remarkable combination of strong support and appropriate flexibility by reason of its structure comprising bony vertebrae separated by intervertebral discs of softer and flexible tissue that allow limited motion between adjacent vertebrae in flexion-extension, lateral bending, and torsion. Each individual flexible element of the spine, comprising a pair of adjacent vertebrae separated by an intervertebral disc, constitutes a spinal motion segment. The proper function of such a spinal motion segment requires the intervertebral disc to provide proper separation between the vertebrae while allowing sufficient relative motion in the median, coronal and transverse anatomical planes of the body. While each intervertebral disc typically performs its function effectively without conscious awareness, the disc and surrounding tissues are provided with ample innervation that informs the individual of any damage and/or malfunction by providing a pain signal.
The spinal regions most susceptible to painful pathology of the intervertebral disc are the cervical and lumbar regions. Such painful pathology is typically the result of some traumatic injury or age-related changes in the structure and function of the intervertebral disc.
The most common pathologic condition causing chronic low back pain and neck pain is degenerative disc disease (DDD), which is typically the result of age-related changes in the tissues constituting the intervertebral disc, with accompanying abnormalities, e.g., deformation, in the functional structures of the disc. Under such conditions, even normal movement between the adjacent vertebrae can cause pain, which may become chronic and sufficiently severe to result in significant disability. When non-invasive treatment fails to relieve chronic disabling back pain caused by such disease, recourse is had to surgical intervention. For some time, palliative surgical procedures such as disc excision, decompression, and/or spinal fusion have been performed to relieve intractable pain of patients with degenerative disc disease. More recently, artificial intervertebral disc prostheses have been developed, which have made it possible to replace a degenerated disc with such a prosthesis to achieve pain relief and restore anatomical function.
A number of factors must be considered in the design of an intervertebral disc prosthesis if a successful outcome of disc arthroplasty is to be expected. The prosthesis design must provide for proper positioning, correct alignment, congruent contact surface area, and immediate post-operative prosthetic stability within the disc space. In particular, the conformation of the vertebra-contacting surface of the prosthesis at the vertebra-prosthesis interface is of significant importance, particularly for post-operative stability of the prosthesis in the intervertebral space. Experience has shown that the clinical results of intervertebral disc arthroplasty are closely correlated to the proper initial positioning of the disc prosthesis in the disc space and subsequent maintenance thereof. For instance, if an implanted disc prosthesis does not maintain a stable position within the intervertebral space, the patient may experience post-operative accelerated disc degeneration in adjacent spinal motion segments, as well as formation of osteophytic growths on the vertebrae.
Another possible post-operative complication is subsidence of the disc prosthesis into an adjacent vertebra. Such instability is related to at least three factors: contact area between the prosthesis and the adjacent vertebral body, bone mineral density in the contacting surface of the vertebral body, and applied load. In particular, the effective prosthesis-vertebra contact area is affected by the variable curvature and irregular surface profile of the adjacent vertebra, both of which vary significantly from patient to patient, e.g., in the lumbosacral spine which is the site of many intervertebral disc arthroplasties.
The great variety of designs that have been proposed for the bone-contacting surface of intervertebral disc prostheses can be taken as evidence that an ideal design has yet to be achieved. Examples of such prostheses have included those with relatively flat vertebra-contacting surfaces, those with domed profiles, or those incorporating other specially configured shapes such as corrugated or serrated surfaces or protruded platforms.
Besides the general shape of the bone contacting surface, known intervertebral disc prostheses have incorporated additional structures to enhance the security of fixation to the vertebral bone. Some designs have incorporated provisions for fixation using screws driven either into the anterior or lateral sides of the adjacent vertebrae or into the vertebral endplate itself. The bone-contacting surfaces of other prostheses have been provided with spikes, keels, serrations, or the like, in order to provide stable fixation of the prosthesis.
However, certain drawbacks have been observed with the previously known intervertebral disc prostheses. For example, flat prosthetic endplate designs present problems of incongruous fit between the prosthetic endplate and the concave end surface of the vertebral body. Such a mismatch between the shapes can result in post-operative instability of the prosthesis in the disc space, in particular, settling of the prosthesis into the adjacent vertebra (subsidence). Designs that attempt to compensate for this mismatch by providing additional structures such as keel, spikes, and the like incur problems due to the greater distraction between vertebrae required for their implantation. Designs that employ screws placed into the endplates of the vertebrae encounter difficulties in implantation because of the limited working space and the relatively thin bone structures of the vertebral endplates, which do not provide a strong substrate for screw fixation.
Some intervertebral prostheses have incorporated endplates having dome-shaped surfaces for contact with the adjacent vertebral bodies. Both spherical domes and ellipsoidal domes have been employed. Ellipsoidal domes better approximate the planform of a vertebral body, and, when seated in a corresponding ellipsoidal seat reamed in the endplate of the vertebral body, provide a measure of torsional stability. However, preparation of such an ellipsoidal seat and proper alignment with the vertebrae can present some surgical difficulties. Spherical domes, having a circular planform, are more easily fitted to a prepared seat, but, by themselves, tend to provide less torsional stability.
Accordingly, a need has continued to exist for an endplate design that can alleviate the problems experienced in implantation of known intervertebral disc prostheses.

Intervertebral prosthesis endplate having double dome and surgical tools for implanting same


A magnetic bi-stable latch with an upper stator and a lower stator, a rotor between the upper stator and lower stator and adapted for rotation between a first latched position and a second latched position. Each of the stators is a magnetic assembly having at least two inner poles and two outer poles of magnetic material, and at least one stator further having a coil disposed in relation to the inner pole and the outer pole to form an electromagnet. The stators are positioned such that the outer poles of the upper stator align with the inner poles of the lower stator and the inner poles of the upper stator align with the outer poles of the lower stator. The rotor has permanent magnets mounted thereon such that in the first latched position the permanent magnets are aligned with poles of the upper and lower stators.

There are certain situations for which a bi-stable latch is particularly suited. For example there is a need for a device that could be used to hold a refrigerator door open or closed, or a deployable appendage deployed or stowed. Another use for the bi-stable latch of the present invention is to provide high speed switching for optical elements. Such a switching mechanism is provided in U.S. patent application Ser. No. 10/103,534 to David A. Osterberg, filed Mar. 20, 2002, and assigned to the assignee of the present invention. Various systems and devices such as, for example; optical test instruments and equipment, include one or more optical elements, which may be provided to implement, for example, optical filtering. In some of these systems, it may be desirable to simultaneously switch one or more optical elements into and out of an optical path. Preferably, this optical element switching operation is performed relatively rapidly.
In the past, rapid and simultaneous optical element switching has been accomplished using, for example, a wheel mechanism that is configured to rotate the optical elements into and out of the optical path. In one exemplary wheel mechanism embodiment, the optical elements are arranged around the perimeter of a wheel. As different optical elements are to be moved into and out of the optical axis, a motor or other driver rotates the wheel, stopping when the desired optical element is in the optical path.
Although wheel mechanisms generally operate safely, these mechanisms also suffer certain disadvantages. For example, the configuration of many of these wheel mechanisms provides for sequential, rather than random, access to the elements at the edges of the wheel. As a result, the amount of time and energy that may be used to switch one element into the optical path and another optical element out of the optical path can be undesirably high. This may be most pronounced when the wheel is used to move optical elements into and out of the optical paths that are located on opposite sides of the wheel.
Another drawback of some known wheel mechanisms is that rapid movement of the wheel can cause disturbances in the system. These disturbances can result in, for example, image blur. This can be a significant factor in applications that implement precise optical system control such as, for example, in satellite applications. To compensate for the disturbances a rapidly moving wheel may cause, some systems may implement long settling periods after wheel movement. Other systems may use complex force compensation and/or isolation mechanisms, which can increase the system complexity and, in some cases, simultaneously decrease system reliability. Moreover, some of these complex mechanisms may also dissipate significant power, which can negatively impact the thermal profile of the system.
Hence, there is a need for a switching mechanism that addresses one or more of the above-noted drawbacks. Namely, a switching mechanism that supplies relatively high-speed switching speeds, and/or that dissipates relatively low amounts of power, and/or does not cause significant system disturbances. The present invention addresses one or more of these needs. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.


In a disk storage device, a method and apparatus for correcting a "runout" error by adding to the servo control signal a sinusoidal signal of amplitude and phase derived to cancel the runout error.

Typically, in a disk storage device used in a data processing system, data is stored on a rotating disk in a set of concentric circular patterns termed "tracks". A read/write head or transducer is mounted on a carriage incorporated in a servo system that moves the head radially in a "seek" or "access" function in which the servo system moves a read/write head to a selected track from a previous track. When the head reaches the desired track, the servo system commences a "track following" function in which it accurately positions the head over the centerline of the selected track and maintains it in that position so that the head can record a series of data bits or, alternatively, retrieve a series of bits from the track as the disk rotates under the head. Large-capacity disk drives may incorporate a plurality of such disks mounted for rotation together on a single spindle.
It is common to have the head-positioning servo system sense the position of the read/write head by means of servo signals recorded in tracks on the disk pack and correct for a mispositioning of the head. The servo signals may be embedded in the data, for example, recorded in servo fields at the beginnings of the data track sectors. Alternatively, the servo signals may be recorded on a disk surface dedicated to servo signals.
Particularly where a disk is removable from the drive, there is the possibility that the center of the circular tracks on which data was previously recorded is not coincident with the center of the spindle, due to disk slip or spindle imbalances. This causes an error or disturbance, called a "runout," that is periodic at the frequency of the rotation of the disk.
Prior art methods applicable to correcting the runout error have included the sampling of errors at various points along a data track, storing those errors, and later recalling and applying them to the servo controller. U.S. Pat. No. 4,136,365 to Chick et al. for "Magnetic Disc Storage Devices Having Compensation for Dimensional Changes," describes such a system. U.S. Pat. No. 4,536,809, to Sidman for "Adaptive Misposition Correcting Method and Apparatus for Magnetic Disk Servo System," describes another such system, which dynamically derives and stores optimal correction signals.
The prior art approaches, however, require significant memory and computer overhead for the calculation and storage of correction signals.

Method and apparatus for runout correction due to disk slip or spindle imbalance


The invention relates to a control circuit for a synchronous machine (1) of a dental handpiece, comprising a voltage supply (2) and a clamping circuit (7) connected by switches (6). The invention also relates to a method for determining an angular position of a rotor of a synchronous machine (1), wherein a power supply is switched off for a total period of time (T2), a clamping circuit (7) is connected for a time interval (T1), whereupon an electromotive force is measured, and the angular position is determined from the electromotive force.

Synchronous motors are known as electrical drives, such as for dental handpieces, i.e., synchronous machines operated with a motor, in which a rotor in the stator runs in sync with a moved rotary field.
To control such a synchronous machine, it is further known to determine the position of the rotor relative to the rotating stator field during operation. It is known, for example, from DE 195 27 982 AI to provide sensors for this purpose.
A disadvantage is that such a sensor constitutes an additional expense, and that integrating a sensor—for example, in a dental handpiece—can be problematic, given the hygienic requirements.
Another option for determining the rotor position is to measure the electromotive force (EMF) induced by the rotor. For this purpose, the motor windings must be de-energized, however, which takes a certain amount of time, in which drive output is not available. To reduce this time, it is, for example, known to demagnetize, which, however, results in braking torque.
As a result, there is a continual alternation between drive torque and a lack of torque, or even braking torque. These continuous changes in torque can lead to undesirable vibrations and noises.
A method and a device for determining the angular position of the rotor by measuring EMF are described in EP 0 993 108 A2. The method is based upon determining the electromotive force (EMF) induced in a stator winding by the rotor, wherein the other stator windings are short-circuited, and a power shortage close to a suspected zero crossing is generated.
The disadvantage is the dependency of the measurement on the zero crossing of the stator current. If, however, measurement does not occur close to the current zero crossing, this would yield a much longer wait time with regard to demagnetization, depending upon the momentary current value in the winding.
The object of the present invention is to provide a circuit and a method that make it possible to determine the EMF at any time of operating a synchronous machine, and to demagnetize the motor windings as quickly as possible and keep the overall measuring time short.

Control circuit and control method for a synchronous machine