A liquid crystal display device comprising a liquid crystal panel in which liquid crystals having negative dielectric anisotropy are interposed between upper substrate and lower substrate that have been vertically oriented on the surface, the orientation of the liquid crystals being almost vertical with no applied voltage, almost horizontal when a predetermined voltage is applied, and tilted when a smaller voltage than the predetermined voltage is applied; a first polarizer and a second polarizer disposed on both sides of the liquid crystal panel such that the absorption axes of the polarizers are perpendicular to each other; a first retardation film disposed between the liquid crystal panel and the first polarizer; and a second retardation film disposed between the liquid crystal panel and the second polarizer, wherein the polarizer comprises a polarizing film and a pair of protective films having the polarizing film in between, and wherein at least one of the protective films is a cellulose acylate film satisfying:0≦Re(630)≦10 and |Rth(630)|≦25.

Because of the toughness and flame retardancy, cellulose acylate films have been traditionally used for photographic supports and various optical materials. Particularly, in recent years, cellulose acylate films are frequently used as optical transparent films for liquid crystal display devices. Cellulose acylate films exhibit high optical transparency and high optical isotropy and thus, are excellent as the optical materials for devices dealing with polarization, such as liquid crystal display devices. Therefore, cellulose acylate films have been used heretofore as polarizer protective films, or as supports for optical compensatory films whereby display viewed from a tilted direction can be improved (viewing angle compensation).
A polarizer, which is one of the elements constituting a liquid crystal display device, is constructed by bonding a polarizer protective film to at least one side of a polarizer. A polarizer in general can be obtained by staining a stretched polyvinyl alcohol (PVA) film with iodine or a dichromatic dye.
In many cases, as the polarizer protective film, cellulose acylate films, in particular, triacetyl cellulose films, which can be directly bonded to PVA are used. Such a polarizer protective film should be excellent in optical isotropy, and the characteristics of a polarizer greatly depend on the optical characteristics of the polarizer protective film.
Recent liquid crystal display devices are more strongly demanded for improvements in viewing angle characteristics. Thus, optical transparent films such as polarizer protective films or retardation films (also called optical compensatory films) are required to be more optically isotropic. For an optical film to be optically isotropic, it is important that the retardation value of the film, which is represented by the product of the birefringence and thickness of the film, is small. Especially, in order to improve the display viewed from a tilted direction, it is necessary to reduce the retardation in the front direction (Re) as well as the retardation in the thickness direction (Rth). More specifically, it is needed that upon evaluation of the optical properties of an optical transparent film, Re measured at the film front is small, and Re does not change even though the measurement angle is varied.
To the present, there have been cellulose acylate films having reduced front Re values, but it has been difficult to produce cellulose acylate films having little change of Re with the angle, that is, having small Rth. Thus, there have been suggested optical transparent films having reduced angle change for Re by using polycarbonate films or thermoplastic cycloolefin films instead of cellulose acylate films (for example, JP-A Nos. 2001-318233 and 2002-328233, products available as ZEONOR (Zeon Corp. in Japan), ARTON (JSR Corp.), etc.). However, when used as polarizer protective films, these optical transparent films have a problem in bonding to PVA because the films are hydrophobic. There is another problem that the overall in-plane optical properties of the films are non-uniform.
As a solution to these problems, there has been a strong demand for a further improved cellulose acylate film, which attains excellent suitability for bonding to PVA by lowering the optical anisotropy. More specifically, the solution is an optically isotropic optical transparent film obtained by lowering the frontal Re of the cellulose acylate film to almost zero, and reducing the change in retardation angle, that is, lowering the Rth to almost zero.
In the production of a cellulose acylate film, generally a compound called a plasticizer is added to improve the film-forming performance. Known examples of the plasticizer include phosphoric acid triesters such as triphenyl phosphate and biphenyldiphenyl phosphate, and phthalic acid esters (See, for example, Lecture on Plastic Materials, Vol. 17, Nikkan Kogyo Shinbun, Ltd., "Cellulose Resins", p. 121 (1970)). It is known that some of these plasticizers have an effect of lowering the optical anisotropy of cellulose acylate films, and for example, specific fatty acid esters are known (See, for example, JP-A No. 2001-247717). However, it cannot be said that the effect of lowering the optical anisotropy of cellulose acylate films using these conventionally known compounds is sufficient.
Furthermore, recent liquid crystal display devices are also increasingly demanded to have improved display colors. Therefore, optical transparent films such as polarizer protective films or supports for optical compensatory film are required to have smaller Re or Rth in the visible light region with the wavelength ranging from 400 to 800 nm, as well as smaller changes in Re or Rth dependent on the wavelength, that is, smaller chromatic dispersion.
In general, a liquid crystal display device (LCD) comprises a liquid crystal cell and polarizers. The polarizer comprises protective films and a polarizing film, and is obtained by staining a polarizing film made of a polyvinyl alcohol film with iodine, stretching the polarizing film, and laminating protective films on both sides of the polarizing film. In a transmissive liquid crystal display device, this polarizer is mounted on both sides of the liquid crystal cell, and one or more of optical compensatory sheets may be also disposed. In a reflective liquid crystal display device, a reflective plate, a liquid crystal cell, one or more optical compensatory sheets and a polarizer are disposed in the same order. The liquid crystal cell comprises liquid crystalline molecules, two sheets of substrates to enclose the molecules in between, and an electrode layer to apply voltage to the liquid crystalline molecules. The liquid crystal cell performs ON/OFF display on the basis of the difference in the orientation state of the liquid crystalline molecules, and there have been suggested display modes such as TN (twisted nematic), IPS (in-plane switching), OCB (optically compensatory bend), VA (vertically aligned) and ECB (electrically controlled birefringence), that are applicable both to the transmissive and reflective types.
Among these LCDs, for the uses where high display quality is needed, a 90° twisted nematic liquid crystal display device (hereinafter, referred to as TN mode) which employs nematic liquid crystal molecules having positive dielectric anisotropy and is operated by a thin film transistor, is mainly used. However, the TN mode shows such viewing angle characteristics that although the devices have excellent display characteristics when viewed from the front, their display characteristics deteriorate when viewed from a tilted direction, in a manner such that the contrast is reduced, or there occurs tone reversal in which brightness is reversed in gray-scale display, or the like. Thus, improvements in these characteristics are highly demanded.
In recent years, as a form of LCD having improvements in such viewing angle characteristics, there has been suggested a vertically aligned nematic liquid crystal display device (hereinafter, referred to as VA mode), in which nematic liquid crystal molecules having negative dielectric anisotropy are employed such that the longer axes of the liquid crystal molecules are approximately aligned in a vertical direction on the substrate, without any voltage applied, and these liquid crystal molecules are operated by a thin film transistor (See JP-A No. 11-258605) This VA mode shows excellent display characteristics at a level equivalent to the TN mode when viewed from the front, and also exhibits expanded viewing angle characteristics due to the application of a retardation film for viewing angle compensation.
It is also known that in the VA mode, even expanded viewing angle characteristics can be realized by using a uniaxially oriented retardation film having positive refractive index anisotropy and a negative uniaxial retardation film having the optical axis in a direction perpendicular to the film plane (See JP-A No. 11-258605).
However, in such a VA mode liquid crystal display device, if the optical anisotropy of the transparent protective film (also accomplishing the role as a support) holding the retardation films and the polarizers is not designed to have an appropriate value, satisfactory viewing angle characteristics cannot be obtained. Furthermore, when the PVA film constituting the polarizer contracts under the effect of heat and humidity, stress is exerted on the transparent protective film holding the polarizer, whereby a change occurs in the optical anisotropy of the protective film itself. Thus, there have been failures, in particular, deteriorating the display quality of so-called corner spots, which is light leakage at four corners of the screen.
Thus, a first object of the present invention is to provide a liquid crystal display device having excellent display characteristics and viewing angle characteristics.
In addition, it is also known for the VA mode that characteristics of wider viewing angle can be obtained by using two sheets of negative uniaxial retardation films having the optical axes in a direction perpendicular to the film plane, above and below the liquid crystal cell, and that characteristics of expanded viewing angle can be realized by using uniaxially oriented retardation films having positive refractive index anisotropy and having an in-plane retardation value of 50 nm in this LCD (See SID 97 DIGEST pp. 845-848).
However, use of two sheets of retardation films (See SID 97 DIGEST pp. 845-848) is associated with an increase in the production costs, and has problems that bonding of a plurality of films causes lowering in the process yield, use of a plurality of films causes increased thickness, and it is disadvantages for the thickness reduction of the display device. Furthermore, use of an adhesive layer for laminating stretched films causes contraction of the adhesive layer under changes in temperature and humidity, and thereby defects of delamination or warpage of films may occur. As methods for improving these problems, there are disclosed a method of reducing the number of retardation films (See JP-A No. 11-95208) and a method of using a cholesteric liquid crystal layer (See JP-A Nos. 2003-15134 and 11-95208). However, even these methods necessitate bonding of a plurality of films, and thus are unsatisfactory from the viewpoints of thickness reduction and production costs reduction. Moreover, there have been problems that light leakage in a tilted direction of the polarizer during dark state is not completely suppressed in the visible light region, and the viewing angle is not sufficiently expanded. A more important point is that, complete compensation of light leakage is difficult for the entire range of wavelength of the visible light with respect to the incident light in a tilted direction of the polarizer during dark state, and accordingly there is a problem that azimuthal direction-dependence of color shift occurs. There is also suggested a method of preventing light leakage by controlling chromatic dispersion of the retardation film (See JP-A No. 2002-221622), but there are problems that the difference between chromatic dispersion of the in-plane retardation and chromatic dispersion of the retardation in the thickness direction is not taken into account, and the effect of inhibiting light leakage is insufficient. Furthermore, the effect of changing the birefringence of the liquid crystal layer is not sufficiently considered, and a sufficient effect cannot be obtained, depending on the birefringence value of the liquid crystal layer.
Therefore, a second object of the invention is to provide a liquid crystal display device, particularly a VA mode liquid crystal display device, having high contrast due to accurate optical compensation of the liquid crystal cell. In particular, it is an object of the invention to provide a liquid crystal display device, particularly a VA mode liquid crystal display device, having reduced light leakage in a tilted direction during dark state and thus having improved viewing angle contrast.
Further, for example, Japanese Patent No. 2587398 describes a technique of expanding the viewing angle by applying an optical compensatory sheet, which is produced as discotic liquid crystals are applied on a triacetyl cellulose film, aligned and fixed, to a TN mode liquid crystal cell. However, with regard to liquid crystal display devices to be used for television sets, which are assumed to be viewed from various angles through large screens, it is difficult to require viewing angle dependence therefrom, and it is impossible to satisfy the requirement even with the method described above. Therefore, liquid crystal display devices that are different from the TN mode, such as IPS (In-Plane Switching) mode, OCB (Optically Compensatory Bend) mode and VA (Vertically Aligned) mode, are being investigated. Particularly, the VA mode is attracting interest as a liquid crystal display device for TV, since it has high contrast and a relatively high process yield in the production of large size screens.
As an optical compensatory sheet for the VA mode, there are known a compensatory sheet having a film (plate A) having an in-plane optical axis as an optically positive single axis and a film (plate C) having an optical axis in the normal direction of the film as an optically negative single axis, and a compensatory sheet which can realize viewing angle expansion by using an optically biaxial film (See JP-A Nos. 11-258605 and 11-133413). However, these literatures do not mention about improvements in color shift when the viewing angle is tilted from the front during dark state. In such optical compensatory sheet for the VA mode, the color shift in the case of tilting the viewing angle from the front during dark state can be improved by taking the chromatic dispersion of Re(λ) as a reciprocal chromatic dispersion (Re(λ) in the shorter wavelength side is smaller than Re(λ) in the longer wavelength side), and taking the chromatic dispersion of Rth(λ) as a chromatic dispersion proper (Reλ in the shorter wavelength side is larger than Re(λ) in the longer wavelength side), and an optically biaxial film having such chromatic dispersion characteristics is disclosed (WO 2004/068226 A1).
As a specific embodiment of the optical compensatory sheet for the VA mode, JP-A No. 11-95208 discloses an optical compensatory sheet in which a vertically uniaxially stretched film of a norbornene polymer (trade name: ARTON) and a film in which a layer containing an organic viscous composite (trade name: Lucentite STN, Lucentite SPN) in a hydrophobic resin (trade name: Denkabutyral #3000-K) is formed on a triacetyl cellulose film (trade name: FUJITACK SH-80). However, the Re(λ) chromatic dispersion of the vertically uniaxially stretched film of ARTON is not dependent on the wavelength while being uniform, and the Rth(λ) chromatic dispersion of the triacetyl cellulose film is a reciprocal wavelength distribution. Thus, from the viewpoint of improving the color shift in the case of tilting the viewing angle from the front during dark state, the performance is unsatisfactory. Furthermore, the optically anisotropic layer containing the organic viscous complex in the hydrophobic resin is less durable and soft, and thus the processability of the layer is not good.
As a specific embodiment of the optical compensatory sheet for the VA mode, JP-A No. 2002-311243 describes an optical compensatory sheet prepared from an optically anisotropic layer comprising rod-shaped nematic liquid crystals on triacetyl cellulose (trade name: FUJITACK T-50 SH) and another optically anisotropic layer comprising cholesteric liquid crystals; an optical compensatory sheet prepared from an optically anisotropic layer consisting of a polyimide layer on the triacetyl cellulose and another rod-shaped nematic liquid crystal layer; and a polarizer including an optical compensatory layer, having either of the above-described optical compensatory sheets laminated on a polarizer which employs triacetyl cellulose as a protective film. Even for any one of these two polarizers including optical compensatory sheet, the Re(λ) chromatic dispersion of the optically anisotropic layer comprising rod-shaped nematic liquid crystals is chromatic dispersion proper, and the Rth(λ) chromatic dispersion of the triacetyl cellulose film is reciprocal chromatic dispersion. Thus, from the viewpoints of improving the color shift in the case of tilting the viewing angle from the front during dark state, the performance is unsatisfactory.
Thus, a third object of the invention is to provide an optical compensatory sheet in which ideal chromatic dispersion characteristics capable of improving the color shift in the case of tilting the viewing angle from the front during dark state of a liquid crystal display device, are realized by lamination of a plurality of retardation films; a polarizer employing the optical compensatory sheet as protective films; and a liquid crystal display device employing the polarizer.

Liquid crystal display device, optical compensatory sheet, and polarizer and liquid crystal display device employing the same


Pixel electrodes and a common electrode are formed on a first panel. A wall is formed on the first panel. The wall includes a large insulating wall that is made of an insulating material and projects toward a second panel, and a wall electrode part that covers a side wall of the large insulating wall and functions as the pixel electrode or the common electrode. The wall includes a side surface on which an alignment film that defines an alignment of liquid crystal molecules of a liquid crystal layer is formed. The side wall of the wall is inclined with respect to a direction perpendicular to the first panel and the second panel. With this configuration, in a liquid crystal display device having the wall electrode, light leakage at the time of displaying a black image can be reduced.

1. Field of the Invention
The present invention relates to a liquid crystal display device of an IPS (in-plan switching) system.
2. Description of the Related Art
For example, As shown in JPH06-214244 A, there are liquid crystal display devices of the IPS system where a wall-shaped insulating part is formed in a boundary between two adjacent pixels and an electrode (hereinafter referred to as "wall electrode") is formed on each side surface of the wall-shaped insulating part (hereinafter, a portion including the wall-shaped insulating part and the wall electrodes is called "wall"). Each of the pixels includes two opposed wall electrodes. In an example, one wall electrode functions as a pixel electrode, and the other wall electrode functions as a common electrode. When a voltage corresponding to a gradation value of each pixel is applied to the pixel electrode, a horizontal electric field is developed between the pixel electrode and the common electrode. Liquid crystal molecules rotate due to the electric field, and thus a light of a backlight unit is allowed to transmit through a liquid crystal layer.


An illumination device adapted for attachment to a surface of a rotatable wheel comprises a rigid body having a substantially flat surface to which is attached an adhesive material effective to adhere the illumination device to a desired position on the wheel surface. The illumination device also comprises a light source, a power source, such as one or more batteries, and an electrical circuit that includes a switch for closing the circuit to result in production of light by the light source. The switch may be a motion-activated switch, a simple on-off switch, or other suitable types. In embodiments disclosed, a cavity in the rigid body holds the batteries, and a lamp cover houses the light source (and selected elements of the electrical circuit).

The lighting of the rotating wheels of automobiles and other moving vehicles utilizes a range of devices and strategies, to achieve various types of illumination of those wheels for safety and/or for decorative purposes.
For example, U.S. Pat. No. 5,558,426, issued Sep. 24, 1996 to Dennis and Henry Cabanatan, discloses a set of automobile wheel lights that cast light to the wheels and are mounted on the automobile frame near each respective wheel. U.S. Pat. No. 6,176,603, issued Jan. 23, 2001 to Lester Spicer, discloses a wheeling light system that is mounted behind a wheel and casts light through openings in and/or around the wheel. U.S. Pat. No. 6,612,726, issued Sep. 2, 2003 to Cary Gloodt and James Hutchison, also discloses lighting an automobile system from behind the wheel, in which the wheel covering is at least partly transparent. In the disclosures of these three patents, the power source is located in the automobile body, and not in the rotating wheel.
Other attempts to light rotating wheels provide the lighting devices on the wheel. For example, U.S. Pat. No. 4,763,230, issued Aug. 9, 1988 to Cummings and Rose, disclose a string of lights, and a source of electrical power, connected to each other and attached to spokes of a bicycle wheel. U.S. Pat. No. 6,220,733, issued Apr. 24, 2001 to Gordon, provides a vehicle wheel in which at least one light source and at least one reflective body are arranged. In one disclosed embodiment, a number of light-emitting diodes (LEDs) are mounted proximate to the center of a wheel, and are powered by batteries mounted in the inner hub of the wheel. Reflective bodies aligned to receive light from the LEDs are arranged variously, including by replacing spokes of a wheel with suitably sized and shaped reflective bodies. U.S. Pat. No. 5,530,630, issued Jun. 25, 1996 to Williams, describes a complex assembly for attaching to a wheel, so that lights rotate with the wheel, and are powered, via a commutator, from a power source in the vehicle itself. Also, U.S. Design Pat. No. 332,441, issued Jan. 12, 1993 to Douglas, discloses an ornamental design comprising lights arranged in a circle on an automobile wheel. This patent does not disclose any means of attachment nor powering.
Also, U.S. Pat. No. 5,876,108, issued to Lu Chien on Mar. 2, 1999 teaches a lighting arrangement comprised of a flexible super thin lighting element disposed on a disc-shaped main body arranged to rotate, and a power source and related circuitry. U.S. Pat. No. 6,386,731, issued May 14, 2002 to Cheng, teaches a disc-shaped light, for placement on a rotating wheel, that is powered by a generator disposed in an apparatus in the center of the rotating wheel. U.S. Pat. No. 6,776,458, issued Aug. 17, 2004 to Wang, teaches a plurality of lighting emitting members that are affixed to a wheel cover specifically designed to receive those lighting emitting members. Each light emitting member comprises a light emitting element that is disposed to emit light outward from a point below a plane of the surface of the wheel cover. This appears to result in light being transmitted outwardly from points of the wheel cover, rather than broadcast across a portion of the surface of the wheel cover.
Also, patents have issued that regard a lighting device for a rotating vehicle wheel that is attached to the valve stem of the tire of the wheel. For example, U.S. Pat. No. 6,467,939 issued Oct. 22, 2002 to Deutsch et al., U.S. Pat. No. 6,742,913 issued Jun. 1, 2004 to Deutsch, and U.S. Pat. No. issued Jun. 3, 2003 to Wen Huang. These patents describe devices that are threaded or otherwise attached to the valve stem, and that have a light source that is spaced apart from the surface of the respective wheel or wheel cover so that the main effect of the lighting would appear to create a circular trail of light from the light source during rotation, rather than a substantially reflective effect upon the surface of the respective wheel or wheel cover.
Other references that refer to various aspects of the technologies utilized in lighting and power sources include U.S. Pat. Nos. 5,624,175, 5,497,302, and 6,789,928. These patents as well as all references, patents, patent applications, patent publications, technical publications, scientific publications, and other references referenced herein are hereby incorporated by reference in this application in order to more fully describe the state of the art to which the present invention pertains, and the basic operational variations of various lighting circuits.

Durably affixable light devices for rotating wheels

Abstract: The invention also is directed to forming a lighting pattern on a wheel by positioning such illumination devices on selected positions on the wheel, and activating them to create a desired lighting pattern.


A system for protecting a building or piece of equipment against the forces generated by an earthquake is characterized by one or more approximately horizontal interfaces having sliding means associated therewith which permit relative horizontal multi-directional sliding movement between the superstructure and the supporting substructure. Calibrated control means such as low-friction sliding means and/or adjustable friction clamps may be utilized to adjust the threshold horizontal force required to cause such relative movement. Biasing means such as spring members may be utilized to urge the superstructure towards its pre-earthquake alignment relative to the substructure. Other advantages are provided by substrate grid means that permits the ready adjustment of the friction force exerted by the low-friction sliding means, and by the concave configuration of the sliding interfaces. A method of installing such a system is disclosed.

This invention relates to an improved system for protecting a building, a piece of equipment, or a similar superstructure against damage or collapse due to predicted maximum earthquake vibrations. The invention provides stable and controllable performance during an earthquake, with minimum spatial requirements and minimal costs, and is useful both in the construction of new buildings or equipment installations, and when retrofitting existing structures or equipment installations to enhance their earthquake resistance.
Earthquakes present a major public safety hazard. Building occupants and persons on the streets adjacent buildings and other structures are in peril during an earthquake. In addition, earthquakes create a major economic liability for building owners and communities that depend on the continuity of building usage.
Thus, buildings and equipment, as well as people in and around such buildings and equipment, need protection against the effects of structurally damaging forces generated by the random ground movements of earthquakes. My above-identified previous patents disclose various apparatus for providing such protection. The instant invention provides an improved system for such protection, by enhancing stability and controllability as well as minimizing spatial interferences and costs.
Among other things, my U.S. Pat. No. 3,638,377 explains the bases and method for limiting the horizontal transfer of inertial forces between a superstructure and its substructure, and for calculating an anticipated horizontal displacement of that superstructure with respect to its supporting substructure. As set forth below, after that displacement has been calculated, it may be utilized to determine the dimensions required in the aforementioned minimum spatial interference. As further explained below, that calculated displacement is directly related to the "predetermined distance" discussed hereinbelow.

Earthquaker protection system and method of installing same


The present invention comprises an implementation of a variable data TPI hard drive system. In one embodiment, the system is implemented by configuring a group of servo tracks in a radial direction for a hard drive media. The group is comprised of an integral number of servo tracks that is constant throughout the drive device. The number of data tracks in a group is also an integer but will vary for each surface according to the head used for R/W operations for each media surface. Group boundaries coincide with media surface R/W zone boundaries. The groups are accessed in hard drives having multiple surfaces in a serpentine manner. Data tracks per group are reduced from what is achievable to produce desired target capacities.

With the advances in disk drive technology, the geometry of magnetic recording heads and corresponding data track pitch is continually becoming smaller. As the heads become smaller, the acceptable range of a head's writer width that can be used for a hard disk media surface with a static data track per inch (TPI) format becomes smaller as well. Thus, controlling the writer width to within a percentage tolerance becomes increasingly more difficult. As illustrated in FIG. 1a, a distribution 100 of typically available head writer width versus the probability of the available heads being acceptable for use in a hard drive is illustrated in FIG. 1a. As head writer widths vary from 0 to W, the probability ρ that a head will be acceptable within a hard drive attains a maximum probability P at head width wp. Usable heads have a width within a range of α, which contains the width having the highest probability. As illustrated in FIG. 1a, a range α of acceptable writer widths in a hard drive with a constant track per inch format exists around wp. Typically, the range a of acceptable writer widths is small, thereby limiting the number of manufactured heads that can be used in modern hard drives.
A hard drive system 150 in accordance with one embodiment of the prior art is shown in FIG. 1b. Hard drive system 150 includes a hard drive 121 with parts including a disk controller 118, microprocessor 120, servo controller 110, read/write channel 114, a preamp 116, voice coil motor 108, spindle motor 104, actuator 106, head 105 and disks 102. Hard drive 121 may send and receive information with host(s) 122. In a standard data write operation, data write information is received from host 122 by the disk controller 118. The data to be written is sent by the disk controller to read/write channel 114 and data write instructions are sent to microprocessor 120. The microprocessor sends a signal to the servo controller. The servo controller then sends signals to the voice coil motor 108 to position actuator 106 to the data track and sector of disk 102 to which the data is to be written. Once the data track and sector are selected and the head is aligned with the desired data track, a signal from the servo controller to the read/write channel, in one embodiment, enables a data write operation through the preamp 116 to the disk 102. Throughout write operations and similarly executed read operations, the spacing between data tracks is uniform.
Variable data TPI hard drive systems where data and servo TPI are chosen arbitrarily have been slow to evolve because they involve complicated software and mathematical processes. For this reason, variable data TPI methods are not very well developed in the electronic storage device industry. What is needed is a variable data TPI system and method that overcomes the limitations and disadvantages of the prior art.

This patent is subject to a terminal disclaimer.

Constrained implementation of variable data TPI

Matsushita Electric Industrial Co., Ltd.


The object of the present invention is to provide an electromagnetic vibrating pump which can enhance dust collecting function, reduce the number of times of maintenance working and improve the rate of operation. The present invention is an electromagnetic vibrating pump, having a suction orifice sucking air and vent orifices venting said air in an internal cyclone chamber and equipped with a centrifugal dust collector having a cyclone generating portion at which a generating portion for generating cyclone action to the atmosphere which was sucked in the cyclone chamber through said suction orifice is provided.

As an electromagnetic vibrating pump for sucking and discharging a fluid utilizing the vibration of a vibrator which is equipped with a permanent magnet based on magnetic interaction of an electromagnet and the permanent magnet, there has been conventionally a pump described in FIG. 21 (for example, Japanese Unexamined Patent Publication No. 270556/1996).
The pump is a diaphragm pump and composed of an electromagnet which is arranged facing a frame in a pump frame body 200, a vibrator equipped with a permanent magnet, a diaphragm linked with both ends of the vibrator and pump casing portions which are respectively fixed at both end sides of the above-mentioned frame. Further, the upper portion of the above-mentioned pump frame body 200 is provided with a dust collecting portion 201 for removing such as sand dust and dust in the air and for sucking air. As shown in FIG. 22, the dust collecting portion 201 is composed of a filter 203 which is made of a non-woven cloth of a synthetic fiber and provided in turn in a nearly square or nearly circular dust collecting chamber 202 which is formed in the pump frame body 200, two divisional filter packings 204 and a filter cover 205. Further, a sucking orifice for sucking air is provided at the bottom portion of the above-mentioned dust collecting chamber 202 and an intake 206 of air of the atmosphere is formed between the two divisional filter packings 204 covered with the filter cover 205.
In such arrangement, after air of the atmosphere is sucked from the intake 206, dust is collected with the filter 203, and then the air flows in the pump chamber of the above-mentioned pump casing portions. However, fine dust and fine sand dust which pass the filter 203 cannot be completely removed. Accordingly, there has been a problem that fine sands which pass the filter enter into a gap between a diaphragm being used for a pump and a metal fitting retaining the diaphragm, and the diaphragm is damaged during operation and its life time is shortened. Further, there has been a problem that the number of times of maintenance working for exchanging the diaphragm is increased and the rate of operation of the pump is lowered.


A single layer, lightweight protective garment prepared from a fabric made of woven polytetrafluoroethylene staple fiber yam, the fabric having an outer surface composed fluoropolymer staple fibers.

Protective or hazardous duty garments are widely used in various industries to protect the wearer from hazardous conditions, such as heat, smoke, cold, sharp objects, chemicals, liquids, fumes and the like. For example, foundry workers and others who work with molten metal require garments which protect not only from the high temperatures encountered in their work areas but also from occasional splashes of molten metal, particularly high-melting metals such as aluminum and iron. In such instances, if the molten metal adheres to the garment, a great deal of heat is transferred through the garment to the wearer unless the fabric comprising the garment is so thick as to be excessively cumbersome and uncomfortable to wear.
One example of a protective garment for foundry workers is disclosed in U.S. Pat. No. 4,569,088 to Frankenburg et al. which describes a garment prepared from a composite fabric comprised of an outer layer including a needled batt of polytetrafluoroethylene fibers attached throughout its interface by needling with an inner layer of infusible textile fibers selected from the group consisting of poly(m-phenylene isophthalamide) fibers, poly(p-phenylene terephthalamide) fibers and blends thereof. The outer surface is provided to protect the inner durable fabric layer and to provide a surface upon which molten metal splash will not adhere.

Garment prepared from fluoropolymer staple yarn


An active matrix substrate includes a plurality of pixels arranged in a matrix, a plurality of capacitor lines (11b) extending in one of directions in which the pixels are aligned and in parallel to each other, a plurality of TFTs (5), one for each of the pixels, a protective film (16a) covering the TFTs (5), a plurality of pixel electrodes (18a) arranged in a matrix on the protective film (16a) and connected to the respective corresponding TFTs (5), and a plurality of auxiliary capacitors (6), one for each of the pixels. Each of the auxiliary capacitors (6) includes the corresponding capacitor line (11b), the corresponding pixel electrode (18a), and the protective film (16a) between the corresponding capacitor line (11b) and the corresponding pixel electrode (18a).

A liquid crystal display panel includes, for example, an active matrix substrate, a counter substrate facing the active matrix substrate, and a liquid crystal layer provided between the substrates. On the active matrix substrate, a thin film transistor (hereinafter referred to as a "TFT") is provided for each pixel, which is the smallest unit of an image, and an auxiliary capacitor is provided in parallel to the liquid crystal capacitor of each pixel in order to stably hold electric charge stored in the liquid crystal layer (i.e., the liquid crystal capacitor) of the pixel.
For example, Patent Document 1 describes a TFT panel in which a TFT, a pixel electrode, and an auxiliary capacitor electrode are provided in the vicinity of each of intersections between scan signal lines and data signal lines arranged in a matrix. In the TFT panel, a gate insulating film is provided between the scan signal line and the data signal line and between the auxiliary capacitor electrode and the data signal line, and a dielectric strength improvement insulating film which is provided between the data signal line and the auxiliary capacitor electrode does not protrude outside the auxiliary capacitor electrode, whereby a step which would otherwise be caused by an end portion of the auxiliary capacitor electrode is not formed on the dielectric strength improvement insulating film, and therefore, a break is unlikely to occur in the data signal line on the dielectric strength improvement insulating film.

Active matrix substrate and liquid crystal display panel including the same, and method for manufacturing active matrix substrate with gate insulating film not provided where auxiliary capacitor is provided


A method for measuring cross-relation rates in high-resolution nuclear magnetic resonance (NMR) spectroscopy in which in a homogeneous static magnetic field B.sub.0 in a direction of a z-axis which causes alignment of longitudinal components I.sub.Z.sup.A, I.sub.Z.sup.X of magnetization vectors I.sup.A, I.sup.X of nuclei A, X during a time interval .tau..sub.m a sample substance, preferably dissolved in liquid, with nuclei A and X having different chemical shifts .OMEGA..sub.A and .OMEGA..sub.X is irradiated with a radio-frequency (rf) field and afterwards by action of a suitable rf-pulse sequence the longitudinal magnetization is transferred into a transverse magnetization creating a rf-signal received by a detector, is characterized in that the rf field is composed by at least two weak, selective component fields, the frequencies of these fields being chosen such that the magnetization vectors I.sup.A and I.sup.X are made to nutate in synchronous fashion, the remaining spins of the sample substance substantially being unaffected by this process.

The present invention relates to a method for measuring cross-relation rates in high-resolution nuclear magnetic resonance (NMR) spectroscopy in which in a homogeneous static magnetic field B.sub.0 in direction of a z-axis which causes alignment of longitudinal components I.sub.Z.sup.A, I.sub.Z.sup.X of magnetization vectors I.sup.A, I.sup.X of nuclei A, X during a time interval .tau..sub.m a sample substance, preferably dissolved in liquid, with nuclei A and X having different chemical shifts .OMEGA..sub.A and .OMEGA..sub.X is irradiated with a radio-frequency (rf) field and afterwards by action of a suitable rf-pulse sequence the longitudinal magnetization is transferred into a transverse magnetization creating a rf-signal received by a detector.
Such a method is known from the textbook by D. Neuhaus and M. P. Williamson, The Nuclear Overhauser Effect in Structural and Conformational Analysis, Verlag Chemie, 1989.
Ever since Solomon's celebrated work it has been obvious that the measurement of cross-relaxation rates may provide a unique approach to the determination of internuclear distances in solution. Cross-relaxation, also referred to as the Overhauser effect, leads to a partial exchange of longitudinal magnetization components I.sub.Z.sup.A and I.sub.Z.sup.X. The rate of this process is in principle proportional to the inverse sixth power of the internuclear distance r.sub.AX. However, the trouble with cross-relaxation phenomena is that they are easily perturbed by the presence of further spins. For example, if there is a third spin M such that r.sub.AM and r.sub.MX are both smaller than r.sub.AX, the conversion of I.sub.Z.sup.A into I.sub.Z.sup.X via I.sub.Z.sup.M will be much faster than the direct exchange of I.sub.Z.sup.A and I.sub.Z.sup.X, so that the measurement of the distance r.sub.AX becomes unreliable. Only in isolated spinpairs can one hope to measure distances with reasonable accuracy. In larger spin systems, the initial rate approximation is often invoked to justify the use of the two-spin approximation. Although this approximation is certainly acceptable for dominant interactions, it cannot be applied to weaker long-range Overhauser effects that tend to be overshadowed by stronger interactions.
Therefore, it is an object of the present invention to circumvent the fundamental difficulties described above and to present a method for measuring cross-relaxation rates which can still be used in those cases where the normal nuclear Overhauser effect in the laboratory-frame is perturbed by the presence of further spins.
This object is achieved by the present invention in that the rf field is composed by at least two weak, selective component fields, the frequencies of these fields being chosen such that the magnetization vectors I.sup.A and I.sub.X are made to nutate in synchronous fashion, the remaining spins of the sample substance substantially being unaffected by this process.
The nuclei are irradiated simultaneously with the sidebands of an usually amplitude-modulated rf field, so that their magnetization vectors are synchronously forced into a nutation movement. While the magnetization of the two selected nuclei A and X in a molecule are being stirred in this manner, cross-relation between the nuclear spins can occur in a manner that closely resembles the exchange in the laboratory-frame described by Solomon's equations. Suitably prepared initial conditions lead to simple exponential decays. The cross-relaxation rates may then be derived from the difference of the decay rates. Internuclear distances between selected nuclei may then be derived from these cross-relaxation rates, and this even in cases where normal Overhauser effects are perturbed by the presence of further spins.
The simplest realization of the method according to the present invention assuming that there is no weak coupling J.sub.AX between the spins of the nuclei A and X is that the amplitudes and the frequencies of the component fields are chosen such that together they form an amplitude-modulated rf field in direction of a y-axis orthogonal to the z-axis with a carrier frequency .omega..sub.rf =1/2 (.OMEGA..sub.A +.OMEGA..sub.X) and two sideband frequencies .omega..sub.rf +.omega..sub.a and .omega..sub.rf -.omega..sub.a, .omega..sub.a meaning .omega..sub.a =1/2 (.OMEGA..sub.A -.OMEGA..sub.X).
In particular, a mere sinusoidal amplitude modulation may be chosen such that the field amplitude of the composed rf field follows the function 2.gamma.hd 1B.sub.1 cos.OMEGA..sub.a t, .gamma..sub.1 B.sub.1 2.pi. meaning the amplitude of the two sidebands.
In systems with scalar couplings of the spins of the nuclei A and X to other nuclei (eg. M, k) the sideband amplitudes .gamma..sub.1 B.sub.1 /2.pi. are chosen sufficient to stir the spins of the nuclei A and X with the same nutation frequency, but to be weak enough so that the spins of all neighboring other nuclei are not affected, in particular 10 Hz.ltoreq..gamma..sub.1 B.sub.1 /2.pi..ltoreq.100 Hz, preferably .gamma..sub.1 B.sub.1 /2.pi..apprxeq.50 Hz.
If the time interval .tau..sub.m is chosen to be an integer multiple of the duration of a modulation cycle 2 .pi./.gamma..sub.1 B.sub.1, the magnetization of the nuclei A and X lies completely along the z-direction at the end of the irradiation with the composed rf field.
In a further embodiment of the method according to the present invention a composed rf field which is modulated both in amplitude and phase is irradiated. When doing so the phases of the component fields are spaced from each other by 90.degree. and their amplitudes and frequencies are chosen such that together they yield a phase-modulated rf field orthogonal to the z-axis with a carrier frequency .omega..sub.rf =1/2 (.OMEGA..sub.A +.OMEGA..sub.X) and two sideband frequencies .omega..sub.rf +.omega..sub.a and .omega..sub.rf -.omega..sub.a.
In a preferred embodiment the field amplitude of a component field follows the function .gamma..sub.1 B.sub.1 .multidot.cos.omega..sub.a t and the field amplitude of a component partial field follows the function .gamma..sub.2 B.sub.2 .multidot.cos.omega..sub.a t.multidot.cos.gamma..sub.1 B.sub.1 T. This a kind of spin-lock of the magnetization vectors I.sup.A and I.sup.X.
In order to obtain an optimal observable signal the spin-lock pulse has to be interrupted after an integer number of spin cycles of the duration 2.pi./.gamma..sub.2 B.sub.2, which can be achieved by choosing the time interval .tau..sub.m to be an integer multiple of a cycle duration 2.pi./.gamma..sub.2 B.sub.2.
With the rf field, which is modulated both in amplitude and phase in the case of scalar couplings to spins of neighboring other nuclei the field amplitude of the component fields should also be weak enough so that the spins of neighboring other nuclei are not affected, just as with the above mentioned embodiment of a mere amplitude-modulated rf field. On the other hand, the rf amplitude should be sufficient to lock the resonances of the spins of the nuclei A and X. Therefore, in a preferred embodiment, the extreme amplitudes .gamma..sub.1 B.sub.1 /2.pi. and .gamma..sub.2 B.sub.2 /2.pi. are chosen so that 10 Hz.ltoreq..gamma..sub.1 B.sub.1 /2.pi..ltoreq.100 Hz, preferably .gamma..sub.1 B.sub.1 /2.pi..apprxeq.50 Hz, and .gamma..sub.1 B.sub.1 /.gamma..sub.2 B.sub.2 .gtoreq.1, particularly .gamma..sub.1 B.sub.1 /.gamma..sub.2 B.sub.2 .apprxeq.10.
In an especially preferred embodiment the phases of all component fields are switched through 180.degree. at least once during the time interval .tau..sub.m. Thus the negative effect of an inhomogeneous broadening of the induced nutation frequencies due to non-ideal homogeneous rf fields can be minimized, which results in a refocussing of inhomogeneous dephasing.
For reasons of symmetry it is advisable to switch the phases during a time interval .tau..sub.m at an odd number and to choose the time duration .tau..sub.180 of the irradiation of the rf field with a phase switched through 180.degree. to be equal to the time duration .tau..sub.0 of the irradiation of the rf field with a phase switched through 0.degree..
In order to avoid destructive interferences, the time durations of the single intervals with switched phase are preferably chosen to be equal and an odd multiple of .tau./.omega..sub.a.
With embodiments of the present invention, the sample substance prior to irradiation of the composed rf field can be irradiated with a suitably shaped selective rf pulse sequence causing an inversion of the spin polarization of the nuclei X in relation to the nuclei A, in order to set up the defined initial condition of an anti-symmetric state=I.sub.Z.sup.A -I.sub.Z.sup.X with antiparallel spins of the nuclei A and X.
Such a selective rf pulse sequence may consist of a G.sup.3 -Gaussian cascade, as it is described in an article by L. Emsley and G. Bodenhausen in Chem. Phys. Lett. 165, 469 (1990).
Improved characteristic may be obtained with band-selective "uniform response pure phase" pulses, which are proposed by H. Geen, S. Wimperis and R. Freemann in J. Magn. Reson. 85, 620 (1989).
However, selective inversion of the spin polarization can never be perfectly realized in practice. The really-achievable antisymmetric initial state with anti-parallel spins will thus always differ from the ideal eigenstate of the system, leading to a more or less bi-exponential decay of the spins. In contrast thereto, the symmetric eigenstate .SIGMA.=I.sub.Z.sup.A +I.sub.Z.sup.X with parallel spins of the nuclei A and X always shows mono-exponential decay. With other embodiments of the present invention the symmetry is restored in that prior to irradiation of the composed rf field the sample substance is irradiated with a rf pulse sequence which excites transverse magnetization of the nuclei A and X.
Preferably the rf pulse sequence is modulated in amplitude by sin.omega..sub.a t or cos.omega..sub.a t. Thus phase-correct transverse magnetization is excited via well-defined narrow band widths.
In doing so, the 270.degree. Gaussian pulse described in an article by L. Emsley and G. Bodenhausen in J. Magn. Reson. 82, 211 (1989) may be applied as rf pulse sequences.
In case that the experimental conditions are not quite ideal the defined initial states with transverse magnetization may also be achieved in that G.sup.4 Gaussian pulse cascades are chosen as selective rf pulse sequences which are also described in the above cited article by L. Emsley and G. Bodenhausen in Chem. Phys. Lett. 165, 469 (1990).
If scalar coupling occurs between the spins of the nuclei A and X, i.e. if the scalar coupling constant J.sub.AX .noteq.0, there will be a coherent exchange of magnetization between the nuclei A and X. This will not affect the measuring results if the system at the beginning of the time interval .tau..sub.m is in a symmetric phase-equal magnetization state .SIGMA.=I.sub.Z.sup.A +I.sub.Z.sup.X, .SIGMA.'=I.sub.X.sup.A +I.sub.X.sup.X or .SIGMA."=I.sub.Y.sup.A +I.sub.Y.sup.X.
In contrast, in case of an initial state with opposite phases the observables are modulated by the scalar coupling. This modulation can simplest be separated from the slow incoherent spin exchange by Fourier transformation with respect to .tau..sub.m.
In practice it may prove simpler in consequent measurings to increment the respective time interval .tau..sub.m in integer multiples of the period of oscillation caused by the scalar coupling between the spins of the nuclei A and X.
In order to transfer the longitudinal magnetization of the nuclei A and X at the end of the irradiation with the composed rf field into an observable transverse magnetization, there are several possibilities:
In an embodiment a 270.degree. Gaussian pulse with the frequency of one of the two chemical shifts .OMEGA..sub.A or .OMEGA..sub.X is irradiated as read pulse immediately after irradiation with the composed rf field.
In a further embodiment a 270.degree. Gaussian pulse which is modulated in amplitude by the function cos.omega..sub.a t is irradiated as read pulse immediately after irradiation with the composed rf field. Thus the two nuclear resonance frequencies are simultaneously "hit".
Finally, in a further embodiment of the present invention a non-selective .pi./2 pulse may also be irradiated.
In a preferred embodiment the phase of the read pulses is alternated and combined with it the measuring signal in the detector is alternatingly added or subtracted in order to make sure that really only the remaining z-magnetization and not other transverse components are measured.
The invention will be described and explained hereafter in more detail with reference to the embodiments illustrated in the drawing. The features that can be derived from the description and the drawing may be used in other embodiments of the invention each individually or in any combination thereof.

Measurement of cross-relaxation rates between selected pairs of nuclei


A device for calibrating a gas meter, in which gas to be analyzed is introduced into a measuring chamber by a delivery device via a delivery line. A storage tank is provided containing a calibrating substance, which tank is connected to the measuring chamber via a feed line. The storage tank is designed as a tank through which the gas to be analyzed can flow and has a gas inlet. A flow divider is provided in the course of the delivery line. A partial flow of the gas to be analyzed is sent by the flow divider to the gas inlet via a section of the feed line. The gas meter is an electrochemical measuring cell determining a measured concentration value of the calibrating substance in the gas to be analyzed in the measuring chamber. An infrared meter is provided, which evaluates the gas to be analyzed in the measuring chamber and generates a reference measured concentration value for the measured concentration value determined with the electrochemical measuring cell.

A device for calibrating a gas meter, in which gas to be analyzed is pumped by means of a delivery device from a gas inlet to a gas outlet of a measuring chamber, has been known from DE 35 21 535. To generate a calibrating gas mixture, a defined amount of liquid calibrating substance is delivered with a metering pump from a storage tank into the measuring chamber. The calibrating substance evaporates there and mixes with a purge gas present in the measuring chamber to form a calibrating gas of a predetermined composition. The mixing of the calibrating substance is facilitated by a heater located in the measuring chamber and the convection caused by it within the measuring chamber.
The drawback of the prior-art device is that an expensive pump is needed for the accurate metering of the calibrating substance in order to set a defined percentage of the calibrating substance in the gas to be analyzed. In addition, stable temperature conditions must prevail in the measuring chamber, which cannot be ensured without difficulties in the case of portable meters, which must be small and compact.
A process for determining certain characteristics of a substance that can be caused to engage in electrochemical reactions in a gas sample was disclosed in DE 43 44 196. It was found that the sensor current curves of the electrochemical gas-measuring cell have different rates of reaction for different alcohols. Thus, the rate of reaction for methanol in the measuring cell is only one fifth that for ethanol. Identification of the substance present is possible based on the different rates of reaction.


A packet feeder system having a track extending between a packet feeder and the packet receiving end of a magazine includes a discharge end of the track that is adjustably positionable relative to the receiving end of the magazine. Appropriate sensors are provided for detecting the position of the uppermost packet within the magazine relative to the discharge end of the track and a suitable control unit is responsive to the sensing device for controlling the adjustable position of the discharge end of the track. In addition, the track is provided with sequenced gating for controlling movement of the packets along the track. The gating includes a plurality of barriers spaced along the length of the track by a distance slightly greater than the length of the packets. The control unit is effective to sequentially move the barriers into and out of a packet restraining position in a sequence whereby adjacent barriers are prevented from being out of their restraining positions simultaneously.

The packet feeder system of the present invention relates primarily to a system wherein the packets are fed to the magazine by gravity using a track oriented at an appropriate angle for conveying the packets from a feeder source to the uppermost end of the magazine. Frequently, systems of this type use a vibratory bowl feeder as the source of randomly accumulated packets for delivery to the magazine. The vibratory feeder has the capacity to receive and store the packets and, as a consequence of vibration, to move or drive the packets up a delivery path along the inside wall of the bowl. As the packets climb the path, typically they are oriented end to end, single file. Misoriented packets tend to fall back into the bowl. As the packets approach the exit of the bowl, the geometry of the path, guide rails or other devices can be employed to restrict excessively bunched packets, causing them also to fall back into the bowl so that, at the output of the bowl, the packets preferably move in a single file oriented end to end. The packets exit the bowl and drop onto the surface of a gravity feed track that is inclined downwardly so that the packets slide away from the bowl, generally at a rate faster than that at which they are fed from the bowl. This increased rate tends to separate the packets from one another during delivery to the magazine.
As the packets exit the gravity track, the leading end of the packet lands on top of the uppermost or last packet to enter the magazine. This, of course, stops the forward motion of the packet and the tail or trailing end of the packet falls onto the uppermost packet stacked in the magazine. If the packet entering the magazine falls slightly short, it glances off the top of the uppermost packet and strikes the far wall of the magazine which typically is perpendicular to the path of travel along the gravity track. The packet thus entering the magazine strikes the wall directly or after glancing off the top uppermost packet in the stack and lands in an appropriately ordered and oriented position within the magazine.
Under certain circumstances, the removal of the lowermost packets from the bottom of the magazine may exceed the rate at which the packets are delivered to the uppermost portion of the magazine, thus providing a significant gap between the uppermost packet in the magazine and the packet being delivered by the gravity track. This excess room may provide a sufficient distance so the trailing edge of the packet entering the magazine rapidly falls into the magazine as the leading edge thereof strikes the far wall of the magazine. This can cause significant misorientation of the delivered packet since the packet is free to flip and loose proper orientation before landing on top of the stack within the magazine.
It has also been found that as the packets are delivered from the feeder to the gravity track some packets are stacked one on top of another in either a fully overlapping or partially overlapping (shingled) array. Where the packets are fully overlapping, they act as a unit during their travel along the track and entry into the magazine and no significant misorientation is experienced. However, if the packets are shingled, the result is a significant misorientation within the magazine. Bridges form and prevent the packets from falling neatly into the pile, or the trailing edge of the leading packet is pushed up and over by the second packet rather than being allowed to fall down neatly into the stack within the magazine. As mentioned, when the leading edge of the packet impacts on the far wall of the magazine, the trailing edge of the packet tends to fall downwardly and glances off the top of the uppermost packet in the stack. If the leading edge of the partially overlapping trailing packet is below the trailing edge of the leading packet, the sudden downward motion of the first packet can force the leading edge of the second packet down also so that the second packet actually flips over and proper stacking is completely disrupted.


A cervical extraction collar is constructed so that it does not require taking off of a helmet in the event of a sports injury on the field. A main portion of the collar serves to lock a helmet and shoulder pads together, such as the helmet and shoulder pads of a football player or hockey player. A substance is contained within the main portion of the collar to rigidify the collar, and can be initially drawn away from the main portion into tails extending from the collar. After the main portion is placed between the back of the helmet and the shoulder pads, the substance in the tails can then be reinserted into the main portion to expand and brace the main portion against the back of the helmet on one side, and against the shoulder pads of the player on the other side, thereby providing a cervical support without requiring removal of the helmet to attend to the injury. The materials making up the collar are preferably all transparent to x-rays.

The present invention relates to cervical spinal immobilization device and, more particularly, to a device particularly adapted for use with participants in contact sports wearing impact protective helmets for protecting the head and skull area from impact injuries, and wearing other padding such as shoulder pads.
It has long been known in contact sports, especially football, that impacts are dangerous to the participants. Thus, it has been common to provide various protective equipments for football players and the like, including padding, and especially including impact protective helmets to protect the head and skull area from impact injuries. In addition, due to the often traumatic body collisions occurring in such sports, it has also been common to provide additional protective equipments such as padding for the shoulder area extending around and behind the neck in close proximity to the helmets which are used. This is typical, for example, in football, hockey, lacrosse and the like sports.
While such helmets and shoulder pads have been significant in reducing direct impact injuries from blows to the head, the current style of rigid helmet with face guard has introduced an increased risk of paralyzing injury. This is because the rigid helmet and rigid face guard, combined with the shoulder pads, are braced to prevent direct impact injury to the face area and head, and result in the transfer of all forces to the head as a body. The head and skull being encased within a padded helmet is securely gripped by the helmet and any force applied to the helmet moves the entire head and is concentrated in the cervical region of the spine. This has resulted in an increasing incidence of broken necks and cervical region injuries.
In treating such an injury it becomes important to support and stabilize the cervical region in order to reduce the severity of the injury and minimize the danger of paralysis. Moreover, because of such frequent injury, new standards have been established, in the emergency medical care field, for the proper handling of trauma patients in order to improve the patient's chances for recovery. Such proper handling requires immediate attention to the patient in the injury situation, and thereafter, immediate transport to a medical facility for treatment. Immediate treatment includes completely immobilizing the injury before movement, and stabilizing and holding the injured area in an immobilized manner during transport to the medical facility for treatment.
Several cervical and spinal immobilization devices have been developed. Generally these devices comprise short or long spine boards which are used in association with other devices such as cervical collars, body harnesses or straps. One example of a prior art cervical collar is an inflatable neck and head support for use by wearer. This prior art device is a generally rectangular body of flexible gas impervious material with two side panels that is sealed around its entire periphery to form a closed chamber. A valve is mounted in the body to inflate and deflate the chamber. Fasteners are mounted on spaced portions of the body to allow, upon inflation of the chamber, the forming of an annular shape and retaining the annular shape. A modification of this support includes a thin layer of closed cell foam adhered to a wall of the closed chamber to provide a degree of rigidity to the head support.
A more complex device of the prior art is a cervical support for use in immobilizing victims of spinal injuries. The cervical support includes a cervical splint dimensioned to extend from the top of the head to about mid-back of an adult victim, and is shaped to follow the outline of the victim's head and shoulders. The support includes head and chest straps for securing the victim to the splint. The head straps wrap about the forehead and the chin of the victim, and the chest straps extend over the shoulder and under the opposite arm in criss-cross fashion across the chest.
Another more complex type prior art device is a cervical spine immobilization device made up of a corrugated plastic board member. The device includes a reinforcement panel at a critical central zone. Various portions of the device are held together in their secured locations by straps and belts such as those made of nylon webbing attached to the device.
In the area of sports injuries, particularly where the injured person is wearing a sports helmet, one prior art device, which is used to attempt to prevent injury, provides for a flexible support brace which transfers excessive back motion of a sports helmet through a flexible interlinked brace. The brace floats freely between two spaced circumferential spans on the helmet during normal play, but engages with the helmet and collapses to a braced configuration if the helmet is excessively pulled back or pushed forward. In the braced configuration, helmet loads are transferred to the shoulder pads of the player directly, thus transferring excessive head loads into the chest area of the player where they can be more safely absorbed. This device, while taking advantage of the use of the helmet as part of the support structure, is not used to immobilize the cervical region of a person that has been injured, but is instead used to attempt to avoid injuries by transferring the forces applied to the helmet in the event of impact.
In accordance with the device and method of the invention, the complications of the prior art are avoided and a simple device is provided which serves to immobilize a cervical region of a person who has been injured, while wearing a helmet and shoulder pads, without the necessity of removing the helmet, or require any movement of the injured person prior to complete immobilization, which would risk additional injury to the cervical region.

Cervical extraction collar and method of immobilizing a cervical injury


A circuit for measuring respiratory waveform with impedance method and a method and device for resisting electrical fast transient interference are provided, and wherein an output from the peak detector circuit and a reference signal are input to two input terminals of the comparator circuit, an output terminal of the comparator circuit is connected to a control terminal of the electronic switch, and one terminal of the electronic switch is connected to an output terminal of the signal amplifier circuit and the other to an input terminal of the demodulator/amplifier circuit. If a level of the output signal of the peak detector circuit is greater than the level of the reference signal, the electronic switch is switched off in response to an inversion of the output of the comparator circuit so that the interference is isolated from the next stage circuit. The present invention is prone to be implemented with significant effect.

A circuit for measuring respiratory waveform with impedance method is a small signal detection circuit, which is widely applied to patient monitor. Human thorax has certain basic impedance itself, and the impedance values may be slightly changed in a range from 0.1 ohm to several ohms under the frequency range from about 0.1 Hz to 2 Hz with the variation of thorax volume caused by respiratory exercises. In a method for measuring respiration with impedance methods, a stimulating signal, of which frequency is from 20 kHz to 100 kHz, is applied to a human body through electro cardiac leads, then said signal is modulated with the variation of thorax volume and the envelope of the modulated wave is deemed as a respiratory waveform. Such detection method by means of modulation can eliminate the influences resulting from contact impedance of electrodes, low frequency drift of circuits and low frequency noise.
The EFT interference (i.e., electrical fast transient interference) in power supply is caused by switching inductive loads in power grid. In different circumstances, the amplitude of the EFT interference may be up to 500-4000V with its rise time of nanosecond order, wherein a single pulse may typically persist for several ten nanoseconds, and there are generally several ten pulses with the persistence time ranging from nought point several milliseconds to several milliseconds per burst. EFT interfering signal tends to be overlapped with stimulating signal for respiratory detection through distributed capacitance due to the characteristic of high frequency and high voltage. The EFT interfering signal is returned to the ground via distributed capacitance, human body and electro cardiac leads so that the modulation circuit at the preceding stage of respiratory detection circuit may be directly affected.
Since the basic impedance of respiration generally ranges around 200-2000Ω and there is 100Ω of current-limiting resistance for defibrillation in some electro cardiac cables, the basic impedance may be up to around 4000Ω and the variable resistance lower to around 0.2Ω. Therefore, the amplification factor of measurement circuit is highly required, even up to several ten thousands times, and the occurrence of the slight interference at the preceding stage can bring great effect on respiratory signal. High frequency interference pulses such as EFT, etc. may interfere with the respiratory detection circuit with space coupling or inside the patient monitor, and impose a transient high voltage shock upon the circuit, instead of stable existence all the time, so that it is difficult to eliminate these pulses from respiratory detection signal by means of low-pass filtering. A fundamental solution is to switch off the current loop of interfering signal. For example, by means of adjusting the mechanical structure of the entire machine, the distributed capacitance between power supply of patient monitor and floating circuit is reduced so far as possible. In practice, the power line is set to keep a certain distance as long as possible from the electro cardiac leads so as to reduce the direct coupling, etc.
Below are two methods used for suppressing EFT interference in prior art.
I. The interference may be suppressed by increasing signal-to-noise ratio by means of raising the amplitude of stimulating signal and reducing the amplification factor of the output from the modulation circuit. The effect of such method is limited due to the following two aspects, one is that the amplitude of stimulating signal can not be increased unlimitedly because of the restrictions of power range of the amplifier circuit and safe current via human body, and the other is that the amplification factor at subsequent stage can not be lowered too much in order to ensure the detecting sensibility of respiratory waveform.
II. The performance of resisting EFT interference may be improved by increasing the degree of impedance match at the input sides of leads (such as RA, RLL) for collecting respiratory signal, because if the impedances at the input sides of the leads do not match, a common mode signal which is the EFT interfering signal coupling to the leads will be converted to a differential mode signal along with the result of the occurrence of interference. However, such method requires high precisions of elements and PCB wiring, so it is hard to obtain desired effect in practice.
Thus, from the above description, it can be concluded that the prior art is disadvantageous in limited effect of resisting EFT interference and high demand on circuit design.

Circuit for measuring breath waveform with impedance method and method and device for resisting interference of electrical fast transient

Shenzhen Mindray Bio-Medical Electronics Co., Ltd.


Both ends of a head substrate in a longitudinal direction warp in a direction away from a cross section of a print substrate (in the convex shape) when a sealing resin is cured. A central portion of the head substrate in a longitudinal direction warps in a direction away from the cross section of the print substrate (in the concave shape) when heating elements emit heat. A curing condition when curing the sealing resin is changed corresponding to the concave-shaped warpage occurring when the heating elements emit heat, such that the convex-shaped warpage of the head substrate occurring when the sealing resin is cured is offset by the concave-shaped warpage of the head substrate and thus the heating elements are arranged in a straight line when the heating elements emit heat at the time of printing.

A method of manufacturing a thermal head in the related art will now be described with reference to a thermal head disclosed in JP-A-05-069575, for example. As shown in FIG. 7, a plurality of heating elements 22 are arranged on a head substrate 21 in a longitudinal direction (a row direction of printing) of the head substrate 21.
A method of manufacturing the thermal head includes forming a plurality of heating elements 22 in the longitudinal direction by using a photolithographic technique. In this case, a central portion of the plurality of heating elements 22 is bent downward from both ends of the heating elements 22 by a warpage amount of 't'. The warpage amount of 't' corresponds to the warpage amount of a platen roller 23, which will be described later, occurring at the time of printing.
The head substrate 21 is provided on a head mounting member (not shown) made of, for example, aluminum having an excellent heat-radiating property.
The platen roller 23 presses an ink ribbon and record paper (not shown). As shown in FIG. 8, the platen roller 23 is provided on the heating elements 22 which are bent. The platen roller 23 includes a friction member 23a, such as a rubber cylinder, and a slender mandrel 23b, which is inserted into the center of rotation of the friction member 23a and is rotatably supported by a printer (not shown).
While the platen roller 23 presses the record paper and ink ribbon on the heating elements 22 at the time of printing, the central portion of the platen roller 23 rotating counterclockwise is bent to the direction of arrow C by friction between the record paper and the friction member 23a as shown in FIG. 8.
Since the thermal head in the related art includes the heating elements 22 of the head substrate 21 which are bent by a warpage amount of 't', the platen roller 23 may uniformly press the ink ribbon and record paper on the heating elements 22 by pressure even though the platen roller 23 is bent to the direction of arrow C at the time of printing.
However, since the thermal head in the related art includes a plurality of heating elements 22 which are bent by a warpage amount of 't', a curved line is printed along the heating elements 22 when the heating elements 22 emit heat at the same time. Accordingly, the heat emission of the heating elements 22 is controlled to correspond to the curve of the heating elements 22 by a driver IC (not shown) in order to print a straight line. However, it is very difficult to control the heat emission by means of the driver IC.
Further, when the head substrate 21 of the thermal head is narrow in width 'A', the head substrate 21 is partially thermally expanded by the heat of the heating elements 22 which occurs at the time of printing, such that the central portion of the head substrate 21 warps to the direction of arrow B (called 'banana warpage').
As a result, even though a plurality of heating elements 22 is bent by a warpage amount of 't' before emitting heat, the head substrate 21 may be bent to a direction opposite to that of the heating elements 22 when the heating elements 22 emit heat at the time of printing, and the platen roller 22 may not be uniformly pressured to the heating elements 22.


A free standing frame for suspending a seat therefrom and for relative back and forth swinging thereto, comprises a support base wherein a pair of rear legs are longer than a pair of front legs to provide stability, a pair of frame sections that are assembleable to form a banana or C-shaped frame centered above the rear legs and having an upper end for suspending a seat and a lower end, and means for connecting the lower end of the frame to the base and orienting the frame and the center of gravity relative to the rear legs.

1. Field of the Invention
The present invention pertains to a frame for suspending a seat or seating device therefrom. More particularly, the present invention pertains to a free standing frame for suspending a seat or the like therefrom. Even more particularly, the present invention pertains to a frame for above ground suspension of a chair or other seating device.
2. Description of Related Art
Heretofore, there have been provided frames for above ground suspension of seating devices such as canvas-backed or similar cloth-like chairs. Such devices, by suspending a seat along a vertical axis, provide the same type of relaxation mode as a hammock but in a much more compact area.
These frames have been substantially C-shaped, one-piece members having a ground-engaging base. However, one piece frames create difficulties in packaging and shipping. Previous attempts to make multi-component frames have not met with great success because of stability issues and the like.
The present invention, as is detailed hereinafter, overcomes these deficiencies in the prior art by providing a multi-component frame for suspending a seating device therefrom which is easily packaged for shipping and, concurrently, enables stability in use.


Briefly, in one embodiment, the invention is a method for eliminating common subexpressions in an initial SSA intermediate language representation of at least a portion of a computer program. The method includes (a) inserting a phi-node for an unambiguous definition used in an unambiguous subexpression reaching a join point in the initial intermediate language subsequent to the join point; (b) inserting a phi-node for the unambiguous common subexpression; (c) renaming the unambiguous definition and a subsequent use reached by the definition; and (d) renaming the unambiguous common subexpression.

1. Field of the Invention
The invention relates to a computer implemented method for eliminating common subexpressions while constructing a static single assignment language representation of at least a portion of source code.
2. Related Applications
The invention disclosed and claimed herein is related to the following applications:
(1) my co-pending U.S. patent application Ser. No. 08/831,074, filed herewith, entitled "A Method for Constructing a Static Single Assignment Language Accommodating Arbitrarily Complex Symbolic Memory References" (Attorney Docket No. INPA:002.vertline.P3497); PA1 (2) my co-pending U.S. patent application Ser. No. 08/831,739, filed herewith, entitled "A Method of Using Static Single Assignment to Color Out Artificial Register Dependencies" (Attorney Docket No. INPA:019.vertline.P3941); PA1 (3) my co-pending U.S. patent application Ser. No. 08/829,847, filed herewith, entitled "A Method for Identifying Partial Redundancies in Existing Processor Architectures" (Attorney Docket No. INPA:014.vertline.P3936); PA1 (4) my co-pending U.S. patent application Ser. No. 08/829,933, filed herewith, entitled "A Method for Identifying Partial Redundancies in a New Processor Architecture" (Attorney Docket No. INPA:021.vertline.P4306); PA1 (5) my co-pending U.S. patent application Ser. No. 08/831,159, filed herewith, entitled "A Method for Determining the Set of Variables that May Be Ambiguously Defined at a Point in a Computer Program" (Attorney Docket No. INPA:015.vertline.P3947); PA1 (6) my co-pending U.S. patent application Ser. No. 08/829,980, filed herewith, entitled "A Method for Optimizing a Loop in a Computer Program by Removing Loop-Invariant Loads Outside of a Loop" (Attorney Docket No. INPA:017.vertline.P3939); PA1 x=6 PA1 x=x+5 PA1 x=7 PA1 x=x+8 PA1 t.sub.1 =6 PA1 t.sub.2 =t.sub.1 +5 PA1 t.sub.3 =7 PA1 t.sub.4 =t.sub.3 +8 PA1 a=x+y PA1 b=x+y+z
All these applications are hereby expressly incorporated herein by reference for all permissible purposes as if expressly set forth vebatim herein.
3. Description of the Related Art
Most computer programmers write computer programs in source code using high-level languages such as C, FORTRAN, or PASCAL. While programmers may easily understand such languages, modem computers are not able to directly read such languages. Thus, such computer programs must be translated into a language, known as machine language, that a computer can read and execute. One step in the translating process is performed by a compiler. A compiler translates a source code program into object code. Object code is a machine language description of a source code program. Object code produced by conventional compiling techniques may often be made to execute faster. This improvement is called optimization. Compilers that apply code-improving transformations are called optimizing compilers.
Some conventional optimizing compilers translate high-level computer programs into an intermediate language known as a Static Single Assignment (SSA) representation. This SSA intermediate language is used as a basis to perform certain optimizations. After these optimizations are performed, these conventional compilers translate the SSA intermediate language into optimized object code. A deeper explanation of SSA intermediate languages follows and employs the terminology set forth immediately below.
A statement in a computer program is said to "define" a variable if it assigns, or may assign, a value to that variable. For example, the statement "x=y+z" is said to "define" x. A statement that defines a variable contains a "definition" of that variable. In this context, there are two types of variable definitions: unambiguous definitions and ambiguous definitions which may also be called complex definitions. Ambiguous definitions may also be called complex definitions.
When a definition consistently defines a particular variable, the definition is said to be an "unambiguous definition" of that variable. For example, the statement, "x=y" always assigns the value of y to x. Such a statement always defines the variable x with the value of y. Thus, the statement "x=y" is an "unambiguous definition" of x. If all definitions of a variable within particular segment of code are unambiguous definitions, then the variable is known as an unambiguous variable.
Some definitions do not consistently define the same variable. These definitions may possibly define different variables at different times in a computer program. Thus, they are called "ambiguous definitions." There are many types of ambiguous definitions and the principle common denominator among the many types is that they are not unambiguous definitions. One type of "ambiguous definition" occurs where a pointer refers to a variable. For example, the statement "*p=y" may be a definition of x since it is possible that the pointer p points to x. Thus, the definition may ambiguously define any variable x if it is possible that p points to x. In other words, *p may define one of several variables depending on the value of p. Another type of ambiguous definition is a call of a procedure with a variable passed by reference. When a variable is passed by reference, the address of the variable is passed to the procedure. Passing a variable by reference to a procedure allows the procedure to modify the variable. Still another type of ambiguous definition is a procedure that may access a variable because that variable is within the scope of the procedure. A further type of ambiguous definition occurs when a variable is not within the scope of a procedure, but the variable has been identified with another variable that is passed as a parameter or is within the scope of the procedure. Ambiguous definitions are known by those skilled in the art.
When a statement in a computer program references a variable, the statement is said to "use" the variable. For example, the statement "x=y+z" refers to and is said to "use" y and z. Similarly, y and z (but not x) are "used" in the statement "x[y]=z." A statement that uses a variable contains a "use" of that variable.
A definition of a variable "reaches" a use of that variable if that definition is the last definition of that variable prior to the use. Consider the following straight-line C pseudo code:
The definition in the first statement "x=6" reaches the use in the second statement "x=x+5." Similarly, the definition in the third statement "x=7" reaches the use in the fourth statement "x=x+8." Note that the definition in the first statement does not reach the use of the fourth statement because x is redefined in the second and third statements.
In the above example, the definitions of x in the second and third statements are said to "kill" the definition of x in the first statement in that they nullify the effects of the definition in the first statement. Only unambiguous definitions of a variable can kill other definitions of the variable. Thus, a use can be reached by both an unambiguous definition and a subsequent ambiguous definition of the same variable.
A computer programmer may address a variable by specifying the variable's location in memory. This location is known as the variable's absolute address. This method of addressing is known as direct addressing. Direct addressing commonly occurs when a variable is specified by its name. For example, in the statement "y=x," both y and x are directly addressed.
A computer programmer may also address a variable by specifying an address that refers to a different address, which may specify yet another address. This method of addressing is known as indirect addressing. Common examples of indirect addressing include pointers, arrays and combinations of pointers and arrays. Examples of indirect addressing include a[i], *p, *(p+4), **p, a[b[i]], and *(*p+4). When a variable is indirectly addressed, at least one indirect memory reference is employed to determine the absolute address of the variable.
A variable may be classified based upon the number of indirect memory references employed to determine the absolute address of the variable. For example, as discussed above, y and x may be directly addressed. Thus, there are zero indirect memory references employed to determine the absolute address of both y and x. These variables will be referred to as rank-0 variables.
A variable employing a single indirect memory reference will be referred to as a rank-1 variable. Examples of rank-1 variables include single pointer references and single array references such as a[i], *p, and *(p+4). A variable that requires two indirect memory references will be referred to as a rank-2 variable. Rank-2 variables include double pointer references and double array references and the combination of a single pointer reference and a single array reference. Examples of rank-2 variables include **p, a[b[i]], and *(*p+4). A rank-n variable employs n indirect memory references to determine the absolute address of the variable.
A definition that defines a rank-n variable will be referred to as a rank-n definition. Similarly a use of a rank-n variable will be referred to as a rank-n use. For example, the definition of the array element b[a[i]] is a rank-0 use of the variable i, a rank-1 use of the array element a[i], and a rank-2 definition of the array element b[a[i]].
Returning to the discussion of SSA intermediate languages, when a computer program is conventionally translated into a SSA intermediate language, each variable definition is given a unique name. Further, all the uses reached by that definition are also renamed to match the variable's new name. For example, consider the straight-line C pseudo code discussed above. When this C pseudo code is translated into a SSA intermediate language, the result would be the following:
The symbols t.sub.1 through t.sub.4 represent compiler temporaries. Compiler temporaries are also known by those skilled in the art as temps. Unlike most variables, temps have only a single definition. Because a temp has only a single definition, it may not be defined by an ambiguous definition. Thus, temps are unaliasable scalars. Because temps are unaliasable scalars, an expression using t.sub.1 has a different symbolic meaning from the symbolic meaning of an otherwise identical expression using i. Every use of i cannot be considered equal because i represents an aliasable variable. However, every use of t.sub.1 can be considered equal. While a compiler may not be able to determine the value contained in a temp, every use of that temp will return the same unknown value. Therefore, temps dramatically simplify certain compiler techniques.
Unlike the above straight-line C pseudo code, programs typically also contain branch statements. A branch statement is a statement that selects one set of statements from a number of alternative sets of statements. For example, consider the following if-then-else statement: ##EQU1## The flow of control through this code segment during execution will branch depending on whether p is true or false and will unite again at the statement "x=z*x." The point where the flow of control branches is known as the branch point and the point where it unites is known as the "join points" or the "confluence point."
When this C pseudo code is translated into a SSA intermediate language, the result would be the following: ##EQU2## Depending on the value of p, either t.sub.1 will be defined as 4 or t.sub.2 will be defined as 6. In order to "join" these two definitions, a special definition called a phi-function is inserted at the point where the branches join. A phi-function, which is known in the art, is a function that makes explicit a confluence point for multiple definitions that reach a particular point in a computer program.
The above phi-function contains two operands. An operand is a quantity that enters into (or results from) an operation. The operands indicate which definitions reach the join point. In this example, both t.sub.1 and t.sub.2 reach the join point. Thus, both t.sub.1 and t.sub.2 are operands to the phi-function that defines t.sub.3. As shown above, subsequent uses of x in the original program would use t.sub.3 in the corresponding SSA intermediate language.
Conventional SSA intermediate languages accommodate only rank-0 variables. Ambiguous definitions and uses reached by ambiguous definitions cannot be renamed as temps. Phi-nodes also cannot be inserted in conventional SSA intermediate languages without temps. Therefore, phi-nodes cannot conventionally be inserted in the presence of ambiguity interjected by ambiguous definitions and their uses. Thus, rank-1 and rank-2 variables are not included in conventional SSA intermediate languages. Because such intermediate languages contain only a limited amount of symbolic information, only limited optimizations may be based on such languages. Thus, in order to perform significant optimizations, numerous ad hoc techniques are employed. These conventional techniques are inefficient, incomplete, not well defined, and complex.
One common type of optimization is known as common subexpression elimination ("CSE"). A common subexpression is a subexpression within an expression that was previously computed and whose variables have not changed since the previous computation. For instance, consider the following code segment:
The first statement, or expression, defines the variable a using the subexpression x+y. The second statement, or expression, defines the variable b using the subexpression x+y+z. Both the first and second expressions use the common subexpression x+y to define their respective variables. Each time the subexpression "x+y" is used, the values assigned the variables x and y must be loaded. Thus, if the subexpression can be eliminated by replacing it with a single variable, requiring only a single load, execution time can be reduced. The cumulative effect of eliminating numerous common subexpressions can sometimes significantly reduce execution time.
However, current CSE techniques are part of the ad hoc and inefficient optimization process set forth above. In some cases, the inefficiencies offset the benefits of performing CSE. Current techniques also are not applicable to ran -1 and higher variables. Thus, there is a need for a more efficient CSE technique and a CSE technique that can be applied to rank-1 and higher variables.

Method for performing common subexpression elimination on a rack-N static single assignment language


A grease interceptor and method of use thereof is provided for separating solids, fats, oils, and grease waste (“F.O.G.”), and other particulate matter. The grease interceptor receives waste water in a liquid storage area where solids in the waste water have residence time long enough to gravitationally separate towards the bottom of the liquid storage area and waste that is less dense than water floats to the top of the liquid storage area. A series of features including channels, interrupter plates, and walls can increase the residence time or otherwise improve the separation of waste from the water. In addition, embodiments of the grease interceptor can have tapered access holes that improve visual inspection of the liquid storage area of the grease interceptor.

Historically, interceptors or grease traps have been used in restaurants and other commercial facilities to limit the amount of grease and solid waste carried into sewer systems via waste water. Typical grease interceptors can be categorized as either passive grease interceptors or automatic grease interceptors. Passive grease interceptors require that waste be periodically emptied from the system to prevent waste build up inside a storage volume leading to the grease interceptor not performing as intended. Passive grease interceptors typically include a storage volume with an inlet that allows waste water to flow into the storage volume and an outlet that allows water to flow out of the storage volume. While the waste water is in the storage volume, less dense grease rises within the water to the uppermost level of the water while denser solids sink in the water and settle on the bottom of the storage volume for subsequent removal.
A significant problem with many grease interceptors is that incoming waste water may flush into and through the storage volume with such velocity that it disrupts the solids that have previously settled on the bottom of the storage volume, thereby reintroducing them into the body of water and potentially moving them further along the path of water flow and causing blockages within the storage volume. The incoming high velocity waste water flush and re-agitated solids may also disrupt the floating grease that has already been separated, causing it to potentially be reintroduced into the water flowing out of the storage volume and resulting in waste being expelled with the outflowing water instead of being detained within the storage volume as intended. This is especially true as the storage volume fills up with grease over time, causing the grease/water interface to occur closer to the grease trap bottom.
Another deficiency found in prior art grease interceptors is the inability to quickly and easily determine through visual inspection, the level or amount of the water or grease content within the interior of the storage volume. Prior art devices embody traditional vertical interior wall surfaces at manhole openings. This limits and impedes the angle of visual inspection, resulting in additional, often difficult effort on the part of an inspector to obtain an accurate assessment of the interior content levels.
Yet another deficiency of prior art grease interceptors is the inability to centralize the settlement of solids within the storage volume. As solids flow into the storage volume with the incoming waste water, the uninterrupted water flow creates currents within the storage volume that carry or distribute the solids into various corners or regions of the storage volume, thereby increasing the difficulty of cleaning out the solids from the bottom of the storage volume.
Therefore, there is a need for a grease interceptor that can minimize or prevent incoming high velocity water flows from disturbing either the already settled solids or the already separated grease, and thereby, minimize or prevent waste from leaving the storage volume with the outflowing water. There is also a need for a grease interceptor that can centrally locate the solids flowing into the storage volume when the solids are settled and remain undisturbed. In addition, there is a need for a new grease interceptor that embodies features allowing for increased visual inspection and thereby allowing for easier, faster, and more accurate visual assessment of the interior content levels. There is further a need for a more efficient, cost effective grease interceptor that allows the solids to settle in a centrally localized manner and thereby allows for an easier and faster cleanout of solids from the storage volume.

Grease interceptor and method of use thereof