A projection display device comprising three projection lenses arranged in a row in a side by side relationship and having respective optical axes extending toward a screen, and three liquid crystal display panels forming images of red, green and blue color lights, the liquid crystal display panels and the projection lenses being arranged to form sets individually. A mirror is arranged between the display element and the projection lens of at least one of the sets. Accordingly, one of the display elements is arranged so as to face in a first direction and the adjacent display element so as to face in a second direction. It is thus possible to reduce the distance between the adjacent projection lenses even if the size of the liquid crystal display panels is enlarged.

1. Field of the Invention
The present invention relates to a projection display device used in an image processing field, and more specifically, the present invention relates to a projection display device in which images of red, green and blue color lights formed by display elements such as liquid crystal panels are projected onto a screen by projection lenses and these images are superposed on the screen.
2. Description of the Related Art
In a prior art projection display device for obtaining a large color display, three cathode lay tubes (CRT) and three projection lenses are used to project images of red, green and blue color lights onto a screen so as to superpose these images on the screen. However, the projection display device using cathode lay tubes is very large in size, and it is not actually used.
Recently, projection display devices using liquid crystal panels have been proposed. For example, Japanese Unexamined Patent Publication (Kokai) No. 2-253292 and No. 3-44623 disclose a projection display device comprising a source of light, dichroic mirrors for separating the light from the source into blue, green and red color light, three liquid crystal panels forming images of red, green and blue color lights, respectively, a color mixing optical element(s) such as a dichroic mirror or a dichroic prism for fixing the images formed by the liquid crystal panels, and a projection lens for projecting the mixed images to a screen.
Also, there is another known projection display device disclosed, for example, on pages 201 to 203 of the publication entitled "Color Liquid Crystal Display", published in 1990 in Japan. This projection display device comprises a source of light, dichroic mirrors for separating the light from the source into red, green and blue, three liquid crystal panels forming images of blue, green and red color light, respectively, and three projection lenses arranged in association with the liquid crystal panel to form sets individually. The images of red, green and blue color lights are projected onto a screen by projection lenses and these images are superposed on the screen. This projection display device has a more compact optical system than that of the above described projection display device including the color mixing optical element, and the device as a whole should be made small. Accordingly, in order to obtain a compact device, it is desirable to arrange the device so that three liquid crystal panels and three projection lenses are used for projecting the images of blue, green and red color light onto the screen so as to superpose the images on the screen. Also, in this publication, mirrors are arranged between the liquid crystal panels and the projection lenses, respectively, so that all the liquid crystal panels are arranged in a common vertical plane and the projection lenses are arranged in a horizontal plane.
In the arrangement using three liquid crystal panels and three projection lenses, three projection lenses are arranged in a row in a side by side relationship on a line extending horizontally and parallel to the screen with respective optical axes extending parallel to each other toward the screen. Accordingly, the axis of the central projection lens is directed to the center of the screen, and the axes of the outer projection lenses are directed to positions slightly shifted from the center of the screen. If the axes of all the projection lenses are directed to the center of the screen, the optical axes of the outer projection lenses are inclined relative to the screen, so that the image projected from the outer projection lens is distorted to a trapezoidal shape and does not coincide with the images projected from the remaining projection lenses. Accordingly, the resultant image may be distorted.
To superpose the images on the screen, the centers of the images projected from all of the projection lenses must coincide with the center of the screen. To this end, the axes of the outer liquid crystal panels are preferably arranged at positions slightly shifted from the axes of the associated outer projection lenses, respectively, so that a light obliquely incident on the center of the outer liquid crystal panel and passing through the center of the projection lens reaches the center of the screen. Hereinafter, this is referred to an offset of axis. If the amount of the offset of axis becomes large, a problem occurs in that uneven color distribution and color shift tend to increase because of an unbalanced mixing of red, green and blue color lights and a directional distribution of light intensity occurring on the screen.
Concurring recent requirements for a high definition display (an increase in the number of pixel elements), the size of liquid crystal panels are increasing. In the case where all of the liquid crystal display panels are arranged on a common vertical plane (and all of the liquid crystal display panels face the screen), the distance between the centers of the adjacent liquid crystal display panels is the width of one liquid crystal display panel plus a space between the adjacent liquid crystal display panels. The distance between the centers of the adjacent liquid crystal display panels is smallest when the adjacent liquid crystal display panel are brought into contact. In the prior art, the liquid crystal display panels are substantially coaxially arranged with the projection lenses, respectively, and the distance between the centers of the adjacent projection lenses substantially equals the distance between the centers of the adjacent liquid crystal display panels. When the mirrors are arranged in the prior art, as described in the above referenced publication, the distance between the centers of the adjacent projection lenses substantially equals the distance between the centers of the adjacent liquid crystal display panels, because all of the liquid crystal panels are arranged on a common plane and all of the projection lenses are also arranged on a common plane.
Therefore, the distance between the centers of adjacent projection lenses becomes larger with an increase in the size of the liquid crystal panels. When the distance between the centers of the central projection lens and the outer projection lens becomes larger, the inclination of the line passing through the center of the outer projection lens and the center of the screen becomes larger and the amount of the offset of axis also becomes larger. If the amount of the offset of axis becomes larger, problems arise in that the resolution and brightness of the image at the peripheral region thereof are reduced, the viewing angle dependency of the liquid crystal increases, and the contrast is reduced. For this reason, there are severe requirements for the projection lenses. Also, a problem arises in that uneven color distribution and the color shift become larger since a convergent angle becomes larger.
It is preferable to constitute the screen from a plate having lenticules on opposite surfaces thereof in order to prevent uneven color distribution and color shift. While the screen made by the plate having lenticules on opposite surfaces thereof is effective for preventing uneven color distribution and color shift, resolution of the display is relatively low because it is difficult to manufacture very thin plate having lenticules on opposite surfaces thereof with an accurate pitch. It is preferable to constitute the screen from a plate having a lenticule on one surface thereof and a light diffusion plate in order to improve the resolution of the display, but it is difficult to reduce the uneven color distribution and the color shift when the distance between adjacent projection lenses is relatively large.

Liquid crystal projection display device with mirror


A plant material is preserved by immersing a cross sectional surface of a severed stem, stalk, trunk or vine of a plant material into a preservative solution. The preservative solution can include a suitable dye. The plant material remains intertwined with its trellis, lattice or similar support during a preservation process. Alternatively, the plant material remains in a natural configuration during the preservation process. Also alternatively, the plant material also remains in a natural orientation during the preservation process. The cut stem, stalk, trunk or vine can be immersed in a container of preservative solution, at or near the time the stem, stalk, trunk or vine is severed. The cut stem stalk, trunk or vine of the plant can also be tied to a container of preservative solution. A rain shroud can also be placed over the container of preservative solution that contains the severed stem, stalk, trunk or vine of the severed plant, to protect the preservative solution during the preservation process. The rain shroud prevents the dilution of the preservative and the dyes by rain and the fouling of the solution by dust and debris. The preserved plant material can be a vine, including leaves, stalk, stem, flowers, cones, seeds and/or fruit. A preserved plant material can also be a hop plant, or portions of a hop plant, of the genus and species Humulus lupulus.

The preservation and dying of plant material is a well known process. Because simply drying plant material leaves it brittle and easily destroyed, a preservation process is often used to render the plant more durable for use in decorative arrangements. Often, dyes are also added to enhance or replace the natural color of the plant material for aesthetic reasons.
One known method for preserving plant material involves the use of the plant's own water and nutrient transport system, the xylem. The xylem transports water and dissolved minerals throughout the plant while it is growing, and for a time after the plant is severed from its root system. Once a plant has been severed from its root system, a preservative solution can be introduced by simply exposing the cut xylem to a preservative solution. The preservation solution then replaces the fluids which were supplied to the xylem by the root system. The preservative solution can contain a variety of components selected to preserve the plant's tissues. This known preservation method results in the systemic replacement of the plant material's natural internal fluids with a preservative solution. The preservative solution can also include the coloring of the plant material by adding a dye to the preservative solution.
Several problems arise when preserving plant material using this known method. The plants which are to be preserved and/or dyed must be harvested and transported to a processing location, often resulting in damage to the stem, trunk, stalk or vine of the plant. Moving a plant, especially a vine plant, causes trauma to that plant. Moving a plant can change the configuration of the plant. A plant's configuration is the spatial relationship between its individual branches and vines. Changing the configuration of the plant results in the crimping, kinking or damage to plant tissues. This damage impedes the uptake of preservatives and/or dye solutions.
"Uptake" is a term referring to the infusion of a preservative solution into a plant. "Uptake" is a relative term, without specific units of measure. A plant "uptakes" a solution, meaning the plant pulls the solution from a container into the tissues of the plant.
The orientation of each part of a plant, including leaves and flowers, is naturally controlled by the plant in response to its environment. This environment includes neighboring plants and leaves, sun and shade. Changing the orientation of the plant causes trauma to the plant, and significantly reduces the xylem's efficiency in transporting fluid through the plant.
At a minimum, the careful transport of larger plants to a processing facility for treatment is awkward and time consuming. Transport also results in trauma to the plant due to the change in orientation of the plant which slows the uptake of preservative solution. More importantly, transport results in changes in the plant's configuration which impedes the uptake of preservative solution.
Prior methods fail to address the support of the plant material to be preserved to maintain the configuration and orientation of the plant to facilitate the preservation process. The U.S. Pat. No. 4,828,890 to Tiedeman et al., teaches only the preservation of self supporting plants and shrubs, such as palms and baby's breath. For the varieties listed in Tiedeman et al. '890, the support of the plant material is not critical to the preservation process. A method is needed that enables the preservation of larger vines, trees and shrubs that require support to facilitate and enhance the preservation process.
There are situations where damage to the plants' internal structures impedes the uptake of preservative solutions. One method currently used in those situations has been to apply these solutions directly to the plant tissues. This requires large quantities of solution sufficient enough to totally immerse the plant or plant segments, resulting in added expense and waste. Another current method has been to cut the plant material into segments, or only preserve smaller cuttings, flowers or branches.
These methods increase the number of sites for absorbing the preservative solution, and minimize the distance preserving and coloring solutions must travel through tissues. However, larger displays of preserved plants require intact and entire plants. These prior methods cannot supply plant material for this demand. These prior methods also use more labor to accomplish this unsatisfactory result.
The preservation of hop plants presents particular challenges due to the unwieldy size and shape of the plant. The hop plant, Humulus lupulus, grows on a network of trellises, lattice works, poles, strings and wires which are employed for support. Hop plants typically attain heights of eighteen to twenty feet. The vertically winding stems of hop plants are generally referred to as bines in the hop growing industry. The predominantly horizontal branches from the main bines are referred to as laterals. The female hop cone is at present commercially desirable solely for its lupulin and essential oils, which are used as a flavoring in beer. Hops, an integral ingredient in beer, provide flavor and act as a bacteriostat. Bacteriostats inhibit the growth of undesirable bacteria and mold. Hop plants and have not been preserved for ornamental purposes.
From the foregoing, it can be seen that a need exists for a method that preserves plant material without first injuring the plant material during harvest and transport of the plant material to a processing location.
A related need exists for a method that includes the introduction of a preservative solution into a plant, severed from its root system, performed in a manner that maximizes the uptake of the preservative solution.
A related need exists for a preserved hop plant.
A need also exists for a dye to be added to the preservative solution for the preservation and dyeing of the hop plants and plant material.

Method for preservation of hop plants and hop plant material


An irrigation/aspiration needle has a rigid needle body over which an elastomeric sleeve is fitted. The elastomeric sleeve terminates in a smooth, relatively soft, rounded tip through which a passageway extends, communicating with a passageway in the sleeve which, in turn, communicates with passageways in the needle body and needle mount, forming a liquid flow path through the needle. The softness of the elastomeric sleeve and, particularly, the sleeve tip protects delicate eye tissue when the needle is used for aspiration from or irrigation of the eye during surgery.

The lens of a human eye is held within a capsular bag positioned behind the iris in the anterior chamber of the eye. When the lens becomes damaged or diseased a common surgical technique is to remove the lens and replace it with an artificial intraocular lens (IOL). Removal of the lens is commonly carried out by phacoemulsification, that is, using a needle to which vibrational electrical energy is transmitted by a phacoemulsification hand piece.
During phacoemulsification, the lens is broken into fragments and the fragments are emulsified and then removed from the capsular bag by aspirating the fragments through a cannula formed as part of the phacoemulsification needle. After the lens has been removed, the capsular bag must be cleaned in order to prepare it for the insertion of an IOL. In particular, epithelial and cortical tissue fragments must be removed from the floor and perimeter of the capsular bag.
Complete removal of the cortex is important for several reasons. If the cortex is not completely removed it may cause post-operative inflammation and an increase in intraocular pressure. Incomplete removal of the cortex may also cause decentration or tilting of the IOL which, in turn, would cause a postoperative refractive error or induced astigmatism. This is especially important if the IOL is a multi-focal type. Incomplete removal of the cortex may also result in the formation of another cataract which would impair vision.
The present invention has a relatively soft exterior cover which terminates in a substantially spherical tip larger in diameter than the needle. The ball-like, or rounded shape of the tip presents a softer surface with no angles to lessen the possibility of injury to the cortex. The tip can be used to polish the anterior capsule to remove fine cortical residue as well as any remaining viscoelastic material present after implanting the lens. To aspirate the viscoelastic material, the tip is introduced beneath the IOL accomplishing aspiration without stressing the capsular bag or the ciliary zonules.
It is common to use an I/A needle which is straight along its entire length in order to effect removal of the tissue fragments. This requires movement of the needle across the floor and around the periphery of the capsular bag, a range of motion to which the straight needle is not particularly well-suited. The prior art demonstrates attempts to solve this problem by using curved or curvable needles which attempt to improve maneuverability within the eye during surgery.
It is also known to provide straight needles with round or rounded tips formed from hard, metallic material, and to place the aspiration port at an angle to the needle's central passage to provide increased maneuverability.
It is also known to use a thermoplastic or compliant insert with a metallic needle and to have the insert terminate in a ball-like or bulbous shape with an aspiration port formed therethrough. Placement of the insert on the interior of the needle reduces the cross-sectional area available for flow at the working end of the needle. The aspiration port can be angled with respect to the central needle passage by forming the metallic needle with a beveled end and inserting a compliant sleeve in the needle opening at the bevel. This arrangement leaves bare the edges surrounding the needle opening, creating possible snagging or abrasive surfaces.
U.S. Pat. No. 6,491,670 (Toth et al) teaches and describes the miniaturized surgical instruments especially useful for the opthalmologic surgical procedures and methods of making the same. Toth et al discloses an aspiration needle having an outer, rigid lumen within which a soft or "compliant" insert is placed. The insert terminates in a tip having a generally bulbous shape and through which a passage is formed that communicates with the interior passage in the hollow cannula.
U.S. Pat. No. 5,527,273 (Manna et al) teaches and describes an ultrasonic lipectomy probe and method for manufacture having a rigid shank terminating in an enlarged tip. The shank has a hollow internal passage and the tip has at least one inlet port that communicates with the internal passage of the shank. Certain of the tips have inlet ports formed at an angle to the shank passage.
U.S. Pat. No. 3,808,093 (Abraham) teaches and describes a surgical tool having an ultrasonically vibrating solid needle terminating in a curvilinear needle tip. The needle is not hollow and does not either aspirate or irrigate.
U.S. Pat. No. 4,767,404 (Renton) teaches and describes a surgical suction device having a perforated sleeve. The device includes a hollow needle terminating in a tip that has multiple vacuum ports formed therethrough, communicating with the hollow interior of the needle.
U.S. Pat. No. 5,180,363 (Idemoto et al) teaches and describes an operation device having a hollow, ultrasonically vibrated needle terminating at a tip with the tip having ports that communicate to the interior passage of the needle. Once such tip is formed in a ball-like shape and has a number of ports formed through the surface of the ball or through the surface of the tip to allow irrigating fluid or cooling fluid to pass therethrough.
U.S. Pat. No. 5,653,724 (Imonti) teaches and describes an angled phacoemulsifier tip consisting of a rigid phacoemulsification needle having a distal end which is angled with respect to the main needle body. The tip is beveled but not shaped.
U.S. Pat. No. 5,741,226 (Strukel et al) teaches and describes a phacoemulsification handpiece, sleeve and tip having a rigid ultrasonically vibrated needle terminating in a tip which has a single aspiration port formed therethrough. The tip is disclosed with various shapes including hemispherical and substantially spherical configurations.
U.S. Pat. No. 5,755,700 (Kritzinger et al) teaches and describes a corneal irrigation cannula and method of using. The cannula terminates in a tip which is larger than the diameter of the cannula and which is flattened and has multiple irrigation ports.
U.S. Pat. No. 5,993,409 (Maaskamp) teaches and describes a needle for surgical use. The needle is a phacoemulsification needle which is hollow and has a distal portion which is angled with respect to the needle body.
U.S. Pat. No. 6,126,629 (Perkins) teaches and describes a multiple port phaco needle having a hollow needle body terminating in a generally hemispherical tip and with multiple aspiration ports.
U.S. Pat. No. 6,159,175 (Strukel) teaches and describes a phaco emulsification handpiece sleeve and tip and which discloses one tip configuration which is generally hemispherical in shape and has an aspiration port formed therethrough.
U.S. Pat. No. 6,299,591 (Banko) teaches and describes a phacoemulsification handpiece and sleeve and tip which discloses a needle tip having a generally hemispherical shape and including an aspiration port.
U.S. Pat. No. 6,533,750 (Sutton et al) teaches and describes a conically shaped phaco tip. A phacoemulsification needle formed from a rigid material has a portion proximate the end of the needle that is angled with respect to the main needle body and which includes an aspiration port.
U.S. Pat. No. 7,037,296 (Kadziauskis) teaches and describes a curved multi-purpose phacoemulsification needle featuring a straight phacoemulsification needle having a rounded tip with a flat surface through which an aspiration port is formed at an angle to the axis of the needle. In one variation, the distal end of the needle is curved with respect to the main needle body.
U.S. Pat. No. 6,958,056 (Kadziauskis et al) teaches and describes teaches and describes a curved multi-purpose phacoemulsification needle featuring a straight phacoemulsification needle having a rounded tip with a flat surface through which an aspiration port is formed at an angle to the axis of the needle.
U.S. Pat. D556,322 (Akahoshi) teaches and describes a tip of a phacoemulsification needle. The tip is formed in a generally spherical shape and has a plurality of ports formed therethrough.
International Publication WO 00/74615 (Maaskamp) teaches and describes a phacoemulsification needle having a rigid hollow needle body through which multiple ports are formed proximate the tip which has a port formed therethrough.
European Patent Application EP 1,707,166 (Ghamnoun) teaches and describes an irrigation tip used with a surgical hand piece. The tip has a portion of which is curved at a single bend.
I have determined that using an outer sleeve or cover made from thermoplastic material over a metallic hollow needle results in an I/A instrument that presents a smooth tip surface for polishing the cortex and also allows the tip to have a port formed therethrough which communicates with the hollow passageway in the metallic needle via a tip passageway. The tip port can be placed at any desired location on the tip and the tip passageway is then extended to meet the needle passageway at an angle.
I have also determined that needles so designed can have straight or curved configurations to allow for selectable maneuverability in use.
While the following describes a preferred embodiment or embodiments of the present invention, it is to be understood that this description is made by way of example only and is not intended to limit the scope of the present invention. It is expected that alterations and further modifications, as well as other and further applications of the principles of the present invention will occur to others skilled in the art to which the invention relates and, while differing from the foregoing, remain within the spirit and scope of the invention as herein described and claimed. Where means-plus-function clauses are used in the claims such language is intended to cover the structures described herein as performing the recited functions and not only structural equivalents but equivalent structures as well. For the purposes of the present disclosure, two structures that perform the same function within an environment described above may be equivalent structures.

Composite irrigation/aspiration needle with ball tip


A biplate assembly may include a biplate, a negative electrode and a positive electrode. A method for manufacturing the biplate assembly may involve selecting the size of the biplate and arranging the positive electrode, which is formed by a compressed first powder, to a first side of the biplate. The first powder contains positive active material. The method may also involve arranging the negative electrode, which is formed by a compressed second powder, to a carrier arranged within the biplate assembly. The second powder contains negative active material. The carrier may be a side opposite to the first side of the biplate. The biplate assembly may be implemented in a bipolar battery.

Bipolar batteries have been used to improve battery energy storage capacity on a weight and volume basis, to reduce packing weight and volume, to provide stable battery performance and low internal resistance.
A bipolar battery construction comprises an electrically conductive bipolar layer, a so called biplate, that serves as electrical interconnection between adjacent cells in the battery as well as a partition between the cells. In order for the bipolar construction to be successfully utilized, the biplate must be sufficiently conductive to transmit current from cell to cell, chemically stable in the cell's environment, capable of making and maintaining good contact to the electrodes and capable of being electrically insulated and sealable around the boundaries of the cell so as to contain electrolyte in the cell.
These requirements are more difficult to achieve in rechargeable batteries due to the charging potential that can accelerate corrosion of the biplate and in alkaline batteries due to the creep nature of electrolyte. Achieving the proper combination of these characteristics has proven very difficult. For maintenance-free operation it is desirable to operate rechargeable batteries in a sealed configuration. However, sealed bipolar designs typically utilize flat electrodes and stacked-cell constructions that are structurally poor for containment of gases present and generated during cell operation. In a sealed construction, gases generated during charging then need to be chemically recombined within the cell for stable operation. The pressure containment requirement creates additional challenges on designing a stable bipolar configuration.
In a bipolar battery there is, as mentioned above, a need for electrodes that should be in good contact with the biplate. Presently, the negative and positive electrode being in contact with the biplate are manufactured separately and treated in such a way to improve contact with the biplate when attached to it. Such treatments are disclosed in U.S. Pat. No. 5,611,823, by Klein, where the electrodes are manufactured from electrochemically active material prepared by coating non- to low-conductive particles of a metal hydroxide or metal oxide powder with nickel using a electroless nickel coating process.
Other treatments to manufacture individual robust, positive and negative electrodes is to utilize a current collecting grid for the dual purpose of supporting the electrochemically active materials, and conducting the electric current from the electrode via the conductive grid.
Pressed powder has previously been used when manufacturing separate electrodes. An article, Ni-MH Battery Electrodes Made by a Dry Powder Process was published in the Journal of the Electrochemical Society, Vol. 142, Number 12, December 1995 ("the ECS article"), and is hereby incorporated by reference. Relevant disclosure from the ECS article is bodily incorporated below in paragraphs [0008-20] and in FIGS. 8-27.
The high specific capacity of the Ni-MH battery and the rapidly increasing demand for secondary batteries have led to a rapid increase in the production of Ni-MH batteries. In Japan, the output has doubled each year. For 1994, it reached 206 million cells. In the future, the Ni-MH battery may also be an alternative for electric and hybrid vehicles. For a continuing growth of the Ni-MH market share it is, however, important to reduce the cost of the batteries.
The relative simplicity of the electrode reactions in the Ni-MH battery can help to develop attractive and low-cost batteries. Both electrode reactions according to Equations 1-3, infra, are solid-state intercalation reaction of hydrogen. When the cell is charged, hydrogen is transferred from the Ni(OH)2, which forms NiOOH, to make a water molecule at the electrode surface with an OH− ion from the electrolyte. At the metal hydride (MH) electrode another water molecule is decomposed and a hydrogen atom is intercalated and stored in the MH electrode. When the cell is discharged, the procedure is reversed. In contrast to the Ni—Cd and lead-acid batteries, no water is produced or consumed in the overall cell reactions, and the amount of the electrolyte is thus constant and it participates only as an ionic charge carrier. The metal hydride is further a good electronic conductor both in its charged and discharged state. The main problem is the positive electrode where Ni(OH)2 is an insulator in the discharge state of the electrode. A substantial part of the work presented by the authors of the ECS article, Ye et al. (collectively "the researchers") was, therefore, aimed at improving the conductivity properties of this electrode. Both electrodes were, however, made by cold-pressing dry electrode powder onto an endless metal net, which was a method developed by Svenska Ackumulator AB Jungner in Sweden, in the beginning of 1970s, for the mass production of low cost Ni—Cd consumer batteries. In the present project the same roller pressing equipment was used to produce electrodes for the researchers' Ni-MH test cells. In the beginning of the 1970s, as much as 46 weight percent (w/o) carbonyl nickel powder had to be added to the positive electrode as a binder as well as to enhance the conductivity, in order to obtain good utilization of the nickel hydroxide and an acceptable rate capability for the produced batteries, which increased cost and weight. But now, due to improved nickel hydroxide and carbonyl nickel qualities and the positive influence of Co addition on the performance of the nickel hydroxide, the researchers thought it would be possible to produce commercial batteries by this method, with a performance that can be compared to that of batteries made by Ni foam/felt methods. Furthermore, this dry powder method is more environmentally acceptable than Ni-sinter technologies because it includes no wet chemical steps and reduces spillage and disposal of by-products.Positive:Ni(OH)2+OH−NiOOH+H2O+e−(Eo≈+0.490 V)  [1]Negative:M+H2O+e−MH+OH−(Eo≈−0.828 V)  [2]Total:Ni(OH)2+MNiOOH+MH(Eo≈1.318 V)  [3]
An electrode manufacturing method, originally developed for the production of low cost Ni—Cd cell, has been modified to produce electrodes for Ni-MH cell (sub-C size) in the range 1.5-2.5 Ah. The earlier process reported in U.S. Pat. No. 3,640,772 was dependent on a special treatment of the active material with a polymer dissolved in a solvent. In this treatment, a slurry was made with the active materials and the wet additives after which the solvent was evaporated and the polymer-treated active material formed a solid which was ground into a suitable particle size. In the process described in this paper there is no need for this treatment of the active material. The high-density nickel hydroxide powder and the mischmetal hydrogen storage alloy powder, mixed with certain amount of fine nickel and cobalt metal powder, are directly fed to both sides of a continuous net of woven pure nickel wire at ambient temperature and compacted in an air atmosphere to make electrodes in the form of "endless" bands. No sintering step is needed. The roller pressing equipment is schematically shown in FIG. 8. Finally the bands are cut into suitable electrode lengths. The electrical leads are connected by spot welding and the electrodes are directly coiled together with a separator and inserted into battery cans with a sealing lid for the subsequent evaluation.
The battery characteristics were examined with a PC-controlled multichannel battery charge/discharge system which allows each charge/discharge cycle to be recorded with a 10 mV measuring step and stored on the hard disk of a computer. Time and voltage could both be controlled, and the current could be varied from 10 mA to 20 A. The non-ambient temperature performance of some batteries was measured at the Electrolux Battery Center in Stockholm, Sweden.
The active materials used in this test, i.e., hydrogen storage alloy MmNi3.6Co0.7Al0.35Mn0.35 (Mm; 50-60 w/o La, 30-40 w/o Ce, and about 10 w/o Nd and Pr) and nickel hydroxide (containing 2-4 w/o Co and 3-6 w/o Zn), were generously supplied by Gesellschaft fur Elektrometallurgi in Nürnberg, Germany, and Tanaka Chemical Corporation in Fukui, Japan, respectively. Carbonyl nickel powder (Inco 255, 210) and cobalt powder (MHO extra fine) were used as binders and as conducting additives in both electrodes. The MH electrode composition was fixed at 85 w/o AB5 alloy, 10 w/o Ni, and 5 w/o Co. The carbonyl nickel content in the positive electrode was varied from 46 to 15 w/o, and the effect of cobalt addition was investigated up to 7 w/o. The effects of two kinds of electrolyte were tested, 6 M KOH+1 M LiOH and 10 M KOH which was used in Ni—Cd cells in 1970s. A polyamide nonwoven cloth with thickness 100 μm (FT2119) in two layers was used as separator.
During the work for the ECS article, the researchers came to the conclusion that the positive Ni(OH)2 electrode is in many aspects the weak partner in the Ni-MH battery couple. And because the battery must be Ni-electrode limited in order to enable proper recombination reactions, the researchers put much emphasis on the optimization of this electrode. To improve the electronic conductivity, carbonyl nickel was added to the Ni(OH)2 so that the fine nickel particles form a dendritic structure when pressed together with the Ni(OH)2. Cobalt was also added to improve charge efficiency and utilization. FIG. 9 shows the importance of Co addition and the influence of two different nickel powder qualities (Inco 210 and 255) on the Ni(OH)2 utilization. The utilization of the NiOOHNi(OH)2 reaction refers to a theoretical value of 289 mAh/g of Ni(OH)2 after subtracting the weight of the coprecipitated Zn(OH)2. This Zn(OH)2 addition (amounting to 3.5 w/o) is made by the producer of our starting material in order to suppress a formation of γ-NiOOH which causes electrode swelling and a dry out of the separator upon cycling. The Co additive is further especially important when the amount of conducting Ni powder is reduced. In FIG. 9, the researchers also found that finer grain size Ni (Inco 210) is more effective for increasing the utilization. With this type of powder-pressed electrode the researchers were able to reach a specific capacity of 550 mAh/cm3 at a 0.2 C discharge rate. This is close to what can be obtained with Ni-foam/felt technology. FIG. 10 shows the charge and discharge voltage of an initially optimized battery at a 0.1 C rate. It can be seen that the capacity of the battery is close to 2.4 Ah (i.e., 180 Wh/dm3, 56 Wh/kg) and almost the same as the present commercial cells. This fairly good value can be understood after seeing FIG. 11, where the volume ratio of active material in the three electrode types is compared. The amount of active material in the powder pressed electrode is only about 5 volume percent (v/o) lower than in the foam/felt electrodes leading to comparable total capacities for cells using these two electrode types.
The loss of cycle life is usually caused by a loss of the electrolyte, resulting in a dry out of the cells. A primary cause for electrolyte dry out, which is common for both Ni-MH and Ni—Cd cells, is the incorporation of water molecules in the nickel hydroxide, leading to a swelling of the electrode and a removal of the electrolyte from the separator. Also the corrosion of the metal hydride consumes the electrolyte as well as poor recombination reactions which cause excessive cell pressures and a venting of the cells through the safety valve. In the final stage of the life-span of a hydride battery, both of the latter processes usually occur; this is the reason for the fairly rapid decay of the hydride battery capacity when the battery nears the end of its life expectancy. A typical hydride battery initially has a fairly stable capacity over several hundreds of cycles but eventually reaches a sudden reduction, compared to the Ni—Cd battery where the capacity reduction sets in earlier but is more gradual.
To emulate a suitable starved electrolyte, the researchers varied the amount of electrolyte added and recorded its influence on the internal pressure and internal resistance, as seen in FIGS. 12 and 13. The pressure was measured by removing the safety valve and connecting the cell to an external pressure gauge. With decreasing amounts of electrolyte, the internal pressure decreased as shown in FIG. 12, while the internal resistance increased as shown in FIG. 13, indicating an optimized amount of electrolyte of about 6 g. To prevent the pressure rise during overcharge, an excess of the metal hydride to the nickel electrode (CMH/CNi=1.3) is also needed. This facilitates the recombination reaction of oxygen as well as suppressing a side reaction evolving hydrogen gas at the negative electrode, as can be seen in FIG. 14.
At the beginning, the cycle life was tested by using the IEC standard for Ni—Cd batteries, which means that the cells were charged at the 0.25 C rate for 3 h and 10 min and discharged at the 0.25 C rate for 2 h and 20 min as shown in FIG. 15 (A 1 C rate would correspond to a current that would charge the cell to its nominal capacity during 1 h). The researchers thought, however, that some of the capacity drop is due to an extensive overcharge caused in this IEC standard. The very good charge efficiency of the hydride batteries makes the rather extensive overcharging used for Ni—Cd cells unnecessary. The charge and discharge efficiency for the cells is shown in FIG. 16. Up to about 2.16 Ah of charge input or about 90% of the full 2.4 Ah charging capacity, the charge efficiency is very close to 100%. This is a very important advantage when making large cells, as the amount of dissipated heat that has to be removed can be kept very low, if the cells are not overcharged. This also means that the IEC standard for cycling Ni—Cd cells is not suitable, as it will overcharge the batteries for almost an hour during each cycle. By increasing the discharge time to 2 h and 50 min we could notably reduce the loss of cyclic capacity by removing charge from the cells and thus reducing the amount of overcharge in the subsequent cycle as shown in FIG. 17.
The cobalt addition to the positive electrode, especially at low carbonyl nickel content, was found to be beneficial for the cycle life. As seen in FIG. 15, a 35 w/o addition of carbonyl nickel gives a fairly high utilization, but a very poor cycle life. If 5 w/o of the nickel is replaced by cobalt, the utilization is further increased and the cycle life is dramatically improved. The formation of conducting CoOOH became more important for increasing the charging and discharging efficiencies of the Ni(OH), when the carbonyl nickel content was decreased. Furthermore, the Co addition to the positive electrode influences not only this electrode directly, but also indirectly the negative hydride electrode. FIG. 18 compares the remaining capacity in two sealed cells that have been cycled 350 times at a 0.5 C rate, charging for 2 h and a 0.5 C rate, discharging for 1.6 h. After cycling, the cells were opened and refilled with electrolyte and the discharge curves of both electrodes were measured against an Hg/HgO reference electrode. Initially both cell No. 319 and No. 338 had the same negative overcapacity. After the cycling the negative overcapacity of the cell No. 319 using a Co-free nickel electrode has been lost. In the end, the No. 319 cell became hydride electrode limited. This is the reason that batteries using cobalt-free nickel electrodes quickly lost their capacity as seen in FIGS. 15 and 19. The researchers attributed this corrosion to a poorer charge efficiency of the Co-free Ni electrode, as seen in FIG. 16, causing an evolution of oxygen, which has a detrimental effect on the hydride electrode when it is not fully charged. This is also indicated by the different activation processes for the two kinds of batteries using Co-added and Co-free nickel electrodes. In FIG. 20, the first charge/discharge curves of two different batteries are shown. The form of the charge curves are quite different. The first step of about 1 V in curve b (Co-added nickel electrode) is attributed to the reaction Co(OH)2CoOOH and MMH. At this voltage, almost no oxygen evolution is expected and the hydrogen storage alloy is prevented from oxidization. When the cell is more fully charged, the evolved oxygen can be recombined with the hydrogen in the metal hydride, thus preventing the negative electrode from corroding. But when no Co has been added to the positive electrode, the charge voltage, even at the beginning, is higher (1.4 V) as shown in curve a. At this voltage, oxygen can be evolved at the Ni-electrode and react with the hydrogen storage alloy in the MH-electrode.
The temperature performance was measured at the Electrolux RI Battery Centre in Stockholm, Sweden. FIGS. 21-23 show the discharge curves of the batteries at different temperatures. The cells were charged at room temperature at the 0.2 C rate and rested for at least 2 h, during which time the discharge temperature was established. Cell No. 961 (FIG. 15) had a 10 M KOH electrolyte. Cell No. 359 (FIG. 21) and No. 966 (FIG. 23) had a (6 M KOH+1 M LiOH) electrolyte; cell No. 359 had been through a test with 250 full charge and discharge cycles at a 0.5 C rate before this temperature experiment was done. Comparing the discharge voltage in FIGS. 21 and 23, it is interesting to note that no significant increase in the internal resistance could be observed as a result of these initial 250 cycles. The temperature dependence of the discharge capacity as shown in FIG. 24 was found to be rather flat between −18 and 40° C., except for battery No. 961 with a 10 M KOH electrolyte, where the increased internal resistance at low temperature significantly reduced the capacity at −18° C.
FIG. 25 shows the charge retention at 20° C. The charge retention of the battery was measured as follows. The battery was charged at a 0.1 C rate for 15 h; the charged battery was kept at room temperature for the number of days plotted in the FIG. 25, after which the battery was discharged at a 0.2 C rate to 1 V. The self-discharge rate of the batteries was not large, and we think it can be further improved by replacing the polyamide separator with sulfonated-polypropylene separator.
Two electrolytes, 6 M KOH+1 M LiOH and 10 M KOH which was used in Ni—Cd cells in the 1970s were tested. The 10 M KOH gave a little higher initial capacity as shown in FIG. 26, but also a lower discharge voltage (FIGS. 22 and 26) and a higher internal resistance as shown in FIG. 27. The low temperature performance of the battery with a 10 M KOH electrolyte was very poor as shown in FIGS. 22 and 24.

This patent is subject to a terminal disclaimer.

Method for manufacturing a biplate assembly, a biplate assembly and a bipolar battery


The present invention relates to a detection device and a method for detecting a presence of an object in a surveillance area. The device comprises at least one infrared radiation sensing element each adapted for generating a sensor signal related to a quantity of infrared radiation received from within the surveillance area by the infrared radiation sensing element, a processing unit and an output means for outputting a determined presence of the object and/or a property derived therefrom. The processing unit is adapted for: obtaining the at least one sensor signal; generating at least one contrast value by comparing the at least one sensor signal to at least one reference value; determining the presence of the object by evaluating a condition on said at least one contrast value; and adjusting the at least one reference value such that negative feedback is applied to the at least one contrast value.

Presence or occupancy detection is used in systems that automatically take action when an object of interest, e.g. a person, is present in a region of interest, e.g. a surveillance area. For example, a door, e.g. a sliding door, may be automatically opened when people are standing in front of it, lights may be switched on when a person enters a room or is in the vicinity of the lights, lights may be switched off when no-one is in a room, or an alarm may be triggered when an intrusion is detected.
Several methods of presence detection are known in the art. For example, pressure sensitive sensors or inductive loops may be integrated in a floor in order to detect the presence of persons or vehicles. For heat generating objects, e.g. particularly for persons and/or animals such as pets, detection may involve sensors for detecting infrared radiation emitted by these objects. Infrared detection may be carried out using compact and affordable technology, and has the advantage over other techniques, such as visual image recognition, acoustic sensing or ultrasonic detection, that warm-blooded living beings, such as humans, emit thermal radiation having a characteristic spectral distribution, e.g. a peak around 9.5 μm for humans, and having considerable power, e.g. around 100 W for humans. Since infrared radiation is emitted by these warm-blooded living beings, detection does not require external lighting. Furthermore, many materials which are opaque or only allow limited transmission of light in the visual spectrum are transparent for infrared radiation.
As an example, in state of the art devices for presence or occupancy detection, passive infrared (PIR) sensors are commonly used to detect moving heat generating objects in a surveillance area. Such a PIR sensor transforms infrared energy, e.g. heat radiation, into an electrical signal, e.g. a voltage. The term passive in this instance means that the PIR sensor does not emit an infrared beam but merely passively accepts incoming infrared radiation. PIR sensors for detecting persons may have a wavelength sensitivity peak tuned to around 10 μm, e.g. close to the 9.5 μm, the peak wavelength of infrared radiation emitted by humans. Such a PIR sensor device for occupancy detection is disclosed in U.S. Pat. No. 4,318,089. In this document, a prior art PIR sensor device for presence detection may comprise a pair of spaced apart infrared radiation sensing elements in an enclosure, such as a three-pin metal header package for semiconductor devices, e.g. a TO-5 package. The enclosure may further feature a transparent window in order to limit the radiation transmitted through the window into the enclosure to a suitable wavelength range, e.g. between 5 μm and 15 μm or between 7 μm and 14 μm. Such a transparent window may for example be manufactured from an appropriate material such as germanium, silicon or polyethylene.
In a typical prior art PIR sensor device, the pair of infrared radiation sensing elements may be pyroelectric elements, connected in a voltage bucking configuration, for example connected in anti-phase series, e.g. by an electrically connected pair of matched poles of both elements. Pyroelectric elements have a differential response; a temperature change induces a temporary voltage change over the element which will dissipate due to leakage current at constant temperature. However, a differential readout arrangement over two elements may additionally cancel out signals caused by vibration, ambient temperature changes or field-wide illumination, e.g. by sunlight. The enclosure comprising the pyroelectric elements may further comprise a sensitive field-effect transistor (FET) in order to read out the voltage over the pair of sensitive elements. The two sensitive elements in anti-phase series may for example be grounded on one terminal, and on the other terminal be connected to the gate of the FET and connected to a pull-down resistor.
The prior art sensor devices further typically comprise a focusing element such as a Fresnel lens or a multi-faceted parabolic mirror, in order to project infrared radiation emitted by an object that generates heat, e.g. a person, onto the sensing elements. This focusing element is designed such that radiation emitted by a heat-generating object moving across the surveillance area, e.g. crossing the field of view of the detection device, is projected onto the sensing elements in an alternating manner, i.e. the element on which this radiation is concentrated switches repeatedly. Thus, an alternating current is generated on the output of the FET, which may be further amplified.
The advantage of coupling the elements in a voltage bucking configuration, e.g. in anti-phase series, is that the sensor device becomes insensitive to the environment temperature. However, as the sensing elements never exhibit quite the same characteristics, offsets may arise which have to be filtered out of the system by creating a floating reference level based on an averaging low-pass filter.
In a digital embodiment of this prior art device, further filtering may condition the signal, e.g. to reduce aliasing, before sampling it with an analog-to-digital converter (ADC), usually at a low sampling rate, for example less than 10 Hz, e.g. 5 Hz. The sampling rate is typically quite low due to a low signal-to-noise ratio (SNR), e.g. a SNR of about 2. In the digital domain, the peaks of the filtered signal may be detected, which will trigger an event for a preset duration if it reached a certain level, for example a peak may trigger the switching on of a light or the opening of a door and the restarting of a timer which will switch off the light or close the door after a preset delay, which is usually user-controllable.
Similar analog circuits are known in the art which implement the same or a similar function. In both analog and digital devices, the timer delay and the sensitivity of the device may be controlled by altering a setting.
However, such PIR-based detection method may have disadvantages caused by the inherent differentiating behavior of the design. Such devices only get triggered when moving objects are detected in the surveillance area. For example, when persons stay longer motionless than a timer in a PIR-based sensor device for light switching allows, they might be surprised by the switching off of the light.
In U.S. Pat. No. 4,849,737, another PIR-based detector is disclosed. This prior art sensor is adapted for mechanically scanning a space, e.g. by arranging the PIR-based detector on a rotating disc. Thus, a person which stays substantially motionless with respect to his surroundings can be observed by this prior art PIR-based detector because the motion of the sensor establishes a relative movement between the person and the detector. However, the detection efficiency of such PIR-based sensors may still depend on the relative speed of the detector and the person being detected.
Furthermore, PIR devices as known in the art often require a complex design, e.g. carefully designed Fresnel lenses, to be able to provide an indication of direction of movement of a detected object, e.g. direction of walking of a person. Automatic sliding doors that use PIR sensors to detect persons are therefore typically not arranged at the side-walls of hallways because of the many false alarms that may be triggered by people just passing by.
Furthermore, designing a PIR-based device that is capable of providing an indication of the number of detected objects in a surveillance area, e.g. how many persons are present in a scene, poses further complications. A rudimentary indication of the number of persons present, e.g. distinguishing between a single or multiple persons, would for example be useful in efficient person specific life-style monitoring devices, e.g. for monitoring applications in elderly care in situations where more elderly share the same living spaces.

Infrared presence detector for detecting a presence of an object in a surveillance area

VLAAMSE INSTELLING VOOR TECHNOLOGISCH ONDERZOEK NV (VITO NV)


Multiple fiber channel (FC) storage area networks (SANs) are interconnected over wide-area networks (WANs) to form a long-distance (e.g., greater than about 10 km) distributed storage area network (DSAN) that includes FC to Internet Protocol (IP) over WAN (e.g., SONET or gigabit Ethernet (GE)) gateways that interwork the FC buffer-to-buffer and IP/WAN flow-control mechanisms appropriate to either the SONET or GE link layers using an additive increase, multiplicative decrease (AIMD) congestion avoidance algorithm. The gateways effectively spoof the FC buffer-to-buffer credit mechanism on the FC-interface side of the gateway, while using an IP Internet control message protocol (ICMP) quench mechanism on all WAN links and additionally the IEEE 802.3 pause packet flow control mechanism on gigabit Ethernet (GE) WAN links in combination, in both cases, with a rate-throttling mechanism at the FC<->IP converter.

1. Field of the Invention
The present invention relates to storage area networks and, more specifically, to distribution of storage elements across a wide area network.
2. Description of the Related Art
Recently, the growth in demand for networked storage has exploded. Enterprise applications such as data warehousing, email, and remote backup create hundreds of terabytes of data per day. Storage Area Networks (SANs) and Network Attached Storage (NAS) have become the de-facto technologies for storing, organizing, and distributing the massive amount of data being generated by these applications.
Until recently, storage area networks (SANs) were typically limited to a single site or to operations over a short distance or over low-bandwidth bridges. As the demand for networked storage continues to grow, so does the demand for connecting these "localized islands" of storage over local-area networks (LANs), metropolitan-area networks (MANs), and wide-area networks (WANs).
Traditionally, the need to connect SANs over long distances was driven by applications such as archiving and disaster recovery. Additionally, new time-sensitive applications such as remote web mirroring for real-time transactions, data replication, and streaming services are increasing the demand for high-performance SAN extension solutions.
Connecting SANs over short distances is a relatively straightforward task. Fiber channel (FC), the dominant protocol for SAN connectivity, provides the ability to connect SANs at distances up to 10 km.
An in-development alternative to FC is iSCSI. iSCSI (internet small computer systems interface), a new IP-based storage protocol that will be used in Ethernet-based SANs, is essentially SCSI over transmission control protocol (TCP) over Internet protocol (IP).
The fiber channel family of standards (developed by the American National Standards Institute (ANSI)) defines a high-speed communications interface for the transfer of large amounts of data between a variety of hardware systems such as personal computers, workstations, mainframes, supercomputers, and storage devices that have FC interfaces. Use of FC is proliferating in client/server applications that demand high-bandwidth and low-latency I/O such as mass storage, medical and scientific imaging, multimedia communication, transaction processing, distributed computing, and distributed database processing. More information about fiber channel can be obtained from the National Committee on Information Technology Standards (NCITS) T11 standards organization that regulates FC standards, specifically "Fiber Channel—Physical and Signaling Interface, FC-PH," draft proposed standard, ver. 4.3, ANSI, 1994 (herein "the FC-PH standard"), incorporated herein by reference in its entirety.
Regardless of the technology (FC or iSCSI), performance is affected by many factors such as the distance between the data centers, the transport protocols (e.g., synchronous optical network (SONET), asynchronous transfer mode (ATM), and IP) and the reliability of the transport medium.
Many techniques have been developed to transport FC data through existing data and telecommunications networks. Boxes and systems are beginning to emerge that provide basic extensions of the physical links of FC. These basic-extension systems "stretch" the wire but often don't address system-level issues of FC performance (e.g., end-to-end flow control). Existing extension gateways can tunnel FC data over other transport protocols but only between a few sites. Fiber channel provides an inherently reliable method of transporting data. SCSI (which may ride on FC) presumes that data is delivered in order and reliably. To carry FC outside a data center, an extension system should maintain the same levels of performance and reliability regardless of the distances involved. Efforts focusing on solutions to FC long distance transport are documented by IETF draft standards in the areas of FC-over-IP (FCIP), specifically Rajgopal, M., "Fibre Channel Over TCP/IP (FCIP)", Internet Draft, IPS Working Group, IETF, version 12, Aug. 2002 (herein "the FCIP draft proposal"), incorporated herein by reference in its entirety.
By its nature, IP is unreliable. Mechanisms exist to signal congestion conditions in IP networks but they are generally associated with the dropping of packets. One such mechanism is the ICMP quench message discussed in Postel, J., "Internet Control Message Protocol (ICMP)," Network Working Group, RFC 792, IETF, Sep. '81 (herein "RFC 792"), incorporated herein by reference in its entirety. Layering transmission control protocol (TCP) over IP corrects for errors in packet ordering and packet loss but does so with the insertion of considerable delay and with reduced bandwidth associated with the retransmission and window control mechanisms used in TCP. These mechanisms and their impact on performance for large data transfers over long distances are discussed in more detail in Semke, M., Mahdava, and Ott, "The Macroscopic Behavior of the TCP Congestion Avoidance Algorithm," Computer Communication Review, a publication of the ACM SIGCOMM, vol. 27, number 3, 1997 (herein "Semke '97"), incorporated herein by reference in its entirety.
As enterprise storage needs continue to grow, solutions are needed that can extend the reliable, high-performance characteristics of FC to SAN fabrics of thousands of kilometers, thereby unifying enterprise SAN islands into large geographically dispersed SAN systems.

Flow control between fiber channel and wide area networks


Embodiments of the present disclosure provide a display panel, a method for manufacturing the same, and a display device, relating to the field of display technology. The display panel includes a first substrate, a second substrate, a liquid crystal layer disposed between the first substrate and the second substrate, and a light splitting structure disposed on a side of the first substrate facing away from the liquid crystal layer. The light splitting structure is configured to perform spectroscopic processing on light incident on the light splitting structure to obtain light of at least one color, and project the light of the at least one color onto a pixel of a corresponding color in the display panel.

The liquid crystal display is a typical flat panel display device. The liquid crystal display includes a liquid crystal display panel and a backlight disposed on the back of the liquid crystal display panel. The light emitted by the backlight passes through the liquid crystal display panel to realize image display.
In the related art, as shown in FIG. 1, the liquid crystal display device includes a liquid crystal display panel and a backlight source 100. The liquid crystal display panel comprises a thin film transistor (TFT) substrate 001, a color filter (CF) substrate (i.e., a color film substrate) 002, a liquid crystal layer 003 and a sealant 004 disposed between the TFT substrate 001 and the CF substrate 002, an upper polarizer 005 disposed on a side of the color filter substrate 002 facing away from the liquid crystal layer 003, and a lower polarizer 006 disposed on a side of the TFT substrate 001 facing away from the liquid crystal layer 003. When the liquid crystal display is in operation, the light emitted by the backlight source 100 passes through the lower polarizer 006, the TFT substrate 001, the liquid crystal layer 003, the CF substrate 002, and the upper polarizer 005 in order, and finally enters the human eye. The lower polarizer 006 is used to polarize the light. The lower polarizer 006 and the upper polarizer 005 are arranged so that the light emitted by the backlight source 100 with a specific polarization direction can pass through. The CF substrate 002 is used to filter light. The display panel includes a plurality of pixel units. Each pixel unit can include three pixels, each of which emits light of one color under the illumination of the backlight source.
However, the use of the CF substrate results in loss of light energy, so the light transmittance of the display panel is low, and the display effect of the display panel is relatively poor.

Display panel, manufacturing method thereof, and display device


Matrix-filled liquid radiation curable resin compositions for additive fabrication are described and claimed. Such resins include a cationically polymerizable component that is an aliphatic epoxide, a multifunctional (meth)acrylate component, a cationic photoinitiator, a free-radical photo initiator, and a matrix of inorganic fillers, wherein the matrix further constitutes prescribed ratios of at least one microparticle constituent and at least one nanoparticle constituent. Also described and claimed is a process for using the matrix-filled liquid radiation curable resins for additive fabrication to create three dimensional parts, and the three-dimensional parts made from the liquid radiation curable resins for additive fabrication.

Additive fabrication processes for producing three dimensional objects are well known. Additive fabrication processes utilize computer-aided design (CAD) data of an object to build three-dimensional parts. These three-dimensional parts may be formed from liquid resins, powders, or other materials.
A non-limiting example of an additive fabrication process is stereolithography (SL). Stereolithography is a well-known process for rapidly producing models, prototypes, patterns, and production parts in certain applications. SL uses CAD data of an object wherein the data is transformed into thin cross-sections of a three-dimensional object. The data is loaded into a computer which controls a laser that traces a pattern of a cross section through a liquid radiation curable resin composition contained in a vat, solidifying a thin layer of the resin corresponding to the cross section. The solidified layer is recoated with resin and the laser traces another cross section to harden another layer of resin on top of the previous layer. The process is repeated layer by layer until the three-dimensional object is completed. When initially formed, the three-dimensional object is, in general, not fully cured, and is called a "green model." Although not required, the green model may be subjected to post-curing to enhance the mechanical properties of the finished part. An example of an SL process is described in U.S. Pat. No. 4,575,330, which is hereby incorporated by reference.
There are several types of lasers used in stereo lithography, traditionally ranging from 193 nm to 355 nm in wavelength, although other wavelength variants exist. The use of gas lasers to cure liquid radiation curable resin compositions is well known. The delivery of laser energy in a stereolithography system can be Continuous Wave (CW) or Q-switched pulses. CW lasers provide continuous laser energy and can be used in a high speed scanning process. However, their output power is limited which reduces the amount of curing that occurs during object creation. As a result the finished object will need additional post process curing. In addition, excess heat could be generated at the point of irradiation which may be detrimental to the resin. Further, the use of a laser requires scanning point by point on the resin which can be time-consuming.
Other methods of additive fabrication utilize lamps or light emitting diodes (LEDs). LEDs are semiconductor devices which utilize the phenomenon of electroluminescence to generate light. At present, LED UV light sources currently emit light at wavelengths between 300 and 475 nm, with 365 nm, 390 nm, 395 nm, 405 nm, and 415 nm being common peak spectral outputs. See textbook, "Light-Emitting Diodes" by E. Fred Schubert, 2nd Edition, © E. Fred Schubert 2006, published by Cambridge University Press, for a more in-depth discussion of LED UV light sources.
Many additive fabrication applications require a freshly-cured part, aka the "green model" to possess high mechanical strength (modulus of elasticity, fracture strength). This property, often referred to as "green strength," constitutes an important property of the green model and is determined essentially by the nature of the liquid radiation curable resin composition employed in combination with the type of apparatus used and degree of exposure provided during part fabrication. Other important properties of a stereolithographic resin composition include a high sensitivity for the radiation employed in the course of curing and a minimum amount of curl or shrinkage deformation, permitting high shape definition of the green model. Of course, not only the green model but also the final cured article should have sufficiently optimized mechanical properties.
For select additive fabrication applications in the aerospace or automotive industries, for example, three-dimensional solid parts are subjected to the high force loads of a wind tunnel, or the extreme temperatures of a location proximate to heat-generating componentry. In such applications, designers and engineers require a three-dimensional solid part created via additive fabrication to maintain its structural integrity and minimize deflection. Thus three-dimensional parts made from photopolymerizable compositions must possess ceramic-like material properties, such as high strength, stiffness, and heat resistance.
"Filled" liquid radiation curable resins have long been used in the field in an attempt to meet these specialized application design criteria. That is, high amounts of inorganic filler, such as silica (SiO2) have been imparted into traditional "unfilled" liquid radiation curable resins due to the filler's positive impact on the strength and stiffness of the three-dimensional object produced therefrom. Such filled liquid radiation curable compositions are known in the art of additive fabrication, and are disclosed in, e.g., U.S. Pat. No. 5,972,563 (Issued Oct. 26, 1999), U.S. Pat. No. 5,989,475 (Issued Nov. 23, 1999), U.S. Pat. No. 6,287,745 (Issued Sep. 11, 2001), U.S. Pat. No. 6,742,456 (Issued Jun. 1, 2004), U.S. Pat. Pub. No. 20020045126, U.S. Pat. Pub. No. 20040077745, and U.S. Pat. Pub. No. 20050101684, all of which are hereby incorporated by reference. While the aforementioned patents disclose fundamental filled liquid radiation curable compositions, none discuss or teach compositions sufficiently and simultaneously overcoming the several drawbacks typically associated with their use.
Thus, highly filled compositions present several challenges to the formulator of liquid radiation curable resins for additive fabrication. Heretofore no filled liquid radiation curable composition for additive fabrication existed that could both yield three-dimensional parts possessing excellent mechanical properties, yet simultaneously avoid: (1) a high initial viscosity, (2) a poor viscosity stability, and (3) a tendency to phase separate, resulting in phenomena known as either "soft pack" or "hard pack."
The first long-felt problem with filled liquid radiation curable resin compositions for additive fabrication is that as the amount of filler increases, the viscosity of the resin also usually increases, resulting in decreased workability and processing speed. Highly viscous resins particularly retard the processing speed in vat-based additive fabrication systems such as stereolithography. Existing resins are sufficiently flow-resistant such that they will not readily form a smooth layer of liquid photo curable resin over the just formed solid layer to ensure accurate cure by actinic radiation. Consequently, a recoating operation has traditionally been used to simultaneously place and mechanically smooth a fresh layer of resin over a previously cured layer prior to exposure with actinic radiation. In one non-limiting example, this recoating operation has traditionally been performed by means of a "recoating blade." A recoating blade design is discussed in, for example, Chapman et al., U.S. Pat. No. 5,626,919, assigned to DSM IP Assets, B.V.
Even with a recoating operation, however, low viscosity remains an important characteristic of the resin. The filled liquid radiation curable resin composition's viscosity affects the time it takes to equilibrate as a smooth, even surface after the recoating step. Consequently, a programmed "dwell time" has been traditionally used between the end of the recoating operation and the beginning of the exposure of the next layer of resin to appropriate imaging radiation. Both the recoating operation and the dwell time dramatically increase the process time of a typical vat-based additive fabrication process.
Additionally, the viscosity of the liquid radiation curable resin also affects the time and difficulty associated with preparing a recently-cured part for post processing operations. In a vat-based additive fabrication process, upon build completion of a three-dimensional solid part, the solidified portions are removed from the liquid uncured resin. A highly viscous resin will be more difficult to separate from the cured part, wherein a resin of substantially low viscosity will be removed without significant effort. Thus, low viscosity resins reduce the time required to clean a part in order to prepare it for post processing operations.
Second, while the importance of filled liquid radiation curable compositions for additive fabrication with a sufficiently low initial viscosity is significant, it is equally as important to conduct additive fabrication processes with a resin having sufficient viscosity stability over time. Filled liquid radiation curable resins for additive fabrication possess a well-known amplified tendency to increase in viscosity over time than versus traditional unfilled resins. This exacerbates the aforementioned problems associated with the high initial viscosities of filled compositions, resulting in increasingly less efficient, more costly additive fabrication processes over time.
Additionally, highly filled compositions are usually not as thermal- or photo-stable as non-filled liquid radiation curable resins for additive fabrication. Photo stability is the ability of a liquid radiation curable resin to maintain its viscosity after exposure to ambient light and undesirable light scattering in additive fabrication machines. Thermal stability is the ability of a liquid radiation curable resin to maintain its viscosity after exposure to elevated temperatures, which are known to accelerate cationic polymerization. Because liquid radiation curable resins for additive fabrication include reactive species that are responsive to undesirable ambient light scattering that occurs as a result of contact with crystallized filled particles, partial uncontrolled polymerization occurs in the liquid radiation curable resin after it is exposed to light. This small amount of uncontrolled polymerization, over time, is accelerated if the resin is stored at elevated temperatures. These factors cause the viscosity of the liquid radiation curable resin to increase gradually—but significantly—over time. Thus achieving sufficient viscosity stability is particularly challenging in highly filled liquid radiation curable resins because of additional light scattering effects caused by the filler.
A third problem traditionally associated with filled liquid radiation curable compositions for additive fabrication is their tendency to phase separate in storage or a vat over time. This phase separation, whereby the inorganic filler loses its state of homogeneous suspension in the surrounding liquid radiation curable resin, results in a vat made up of a bifurcated composition: (1) a low-viscosity, largely unfilled top portion, and (2) a supersaturated, high-viscosity bottom portion. The resin in the top portion of a vat is not able to produce cured parts possessing sufficient strength and stiffness (because of a lack of filled component present in the composition), while the bottom portion is devoid of any suitability for additive fabrication at all (due to an excess of filled particles). Despite the historical inclusion of inorganic particles designed for anti-sedimentation, existing filled liquid radiation curable compositions for additive fabrication invariably eventually settle, either into a "soft pack" or a "hard pack." In the more benign settling phenomenon, a soft pack, the settled filler forms a waxy portion at the bottom of a storage container or vat. The settled filler is frequently surrounded by partially polymerized resin, resulting in the wax-like consistency. Although re-assimilation into the liquid radiation curable resin as a whole is possible, it requires frequent and often vigorous recirculation. This is a time- and energy-consuming maintenance process, and still does not obviate a resin's eventual viscosity increase, due to the rampant partial polymerization.
Still other filled liquid radiation curable compositions for additive fabrication settle into an undesirable "hard pack." Hard pack occurs whereby the inorganic filler settles to the bottom of a storage container or vat, forming a concrete-like piece or pieces. These pieces must be broken up by a drill or similar apparatus, and are typically unable to be re-assimilated into the liquid radiation curable resin as a whole. This shortens the shelf-life of such resins, or results in changing and inconsistent properties in the cured parts made therefrom, due to the changing amounts of filler component which are not re-miscible into the solution. Thus, it is especially desirable to formulate a liquid radiation curable resin composition for additive fabrication which, in addition to the other required performance characteristics mentioned above, possesses superior anti-sedimentation capabilities.
Various other patents or patent publications also describe using inorganic filled compositions comprising, inter alia, silica microparticles and/or nanoparticles, among them:
U.S. Pat. No. 6,013,714 (Haruta et al.), assigned to DSM IP Assets, B.V., which describes additive fabrication processes that utilizes filled resins to performing a combination of steps, including (1) applying a thin layer of resin on a supporting stage; (2) selectively irradiating the thin layer of resin as to cure a selected part of said resin; (3) applying a further thin layer of resin; and repeating steps (2) and (3) as to obtain a three dimensional shape of a plurality of cured layers, optionally combined with either one of the steps of washing and post-curing the three dimensional shape, as to obtain the mold, wherein the resin composition is formulated from constituents comprises at least one photoreaction monomer at least one photoinitiator at least one filler.
U.S. Pat. Pub. No. 20050040562 (Steinmann et al.), assigned to 3D Systems, Inc., which describes a process for forming a three-dimensional article by stereolithography, said process comprising the steps: 1) coating a thin layer of a liquid radiation-curable composition onto a surface of said composition including at least one filler comprising silica-type nano-particles suspended in the radiation-curable composition: 2) exposing said thin layer imagewise to actinic radiation to form an imaged cross-section, wherein the radiation is of sufficient intensity to cause substantial curing of the thin layer in the exposed areas; 3) coating a thin layer of the composition onto the previously exposed imaged cross-section; 4) exposing said thin layer from step (3) imagewise to actinic radiation to form an additional imaged cross-section, wherein the radiation is of sufficient intensity to cause substantial curing of the thin layer in the exposed areas and to cause adhesion to the previously exposed imaged cross-section; 5) repeating steps (3) and (4) a sufficient number of times in order to build up the three-dimensional article.
U.S. Pat. Pub. No. 20120251841 (Southwell et al.), assigned to DSM IP Assets B.V., which describes liquid radiation curable resins for additive fabrication comprising an R-substituted aromatic thioether triaryl sulfonium tetrakis(pentafluorophenyl)borate cationic photoinitiator and silica nanoparticles. Also disclosed is a process for using the liquid radiation curable resins for additive fabrication and three-dimensional articles made from the liquid radiation curable resins for additive fabrication.
From the foregoing, it is evident that no filled liquid radiation curable compositions for additive fabrication exist that are suitable for producing cured components having adequate application-specific heat resistance and structural rigidity, while simultaneously overcoming the long-felt but unsolved industry needs of providing the requisite low initial viscosity, high viscosity stability, and high phase-separation resistance.

Stabilized matrix-filled liquid radiation curable resin compositions for additive fabrication


This invention includes compositions of matter made up of a kandite clay which has been treated with large molecules containing multi-atom metallic or semi-metallic species and heated to produce pillars within the clay which are located generally between the clay's layers. The pillared kandite composition is useful as a catalyst support, sorbent, or ion exchanger.. The invention also includes a process for producing the pillared kandite composition comprises mixing the finely divided clay in an aqueous solution with the pillaring medium and heating the resulting composition at a temperature high enough to decompose the added compound.

The term "clay" as used in various areas of technology, is subject to wide variations in meaning. However, an inclusive definition normally would be a naturally occurring sedimentary material generally composed of hydrated silicates of aluminum, iron or magnesium and often containing hydrated alumina and iron impurities. The particles of a clay are typically of at least near-colloidal size in at least one dimension (platelets are typical) and commonly develop thixotropic flow properties when sufficiently pulverized and wetted.
The organization of clay types remained somewhat poor until the development of satisfactory x-ray techniques for studying the atomic structure of individual clays. A paper: Kaolin Materials, U.S. Geological Survey Professional Paper 165-E, C. S. Ross and P. F. Kerr, 1930, pp. 151 to 176, is widely recognized as the beginning of a systematic approach to clay mineralogy. The monograph "Crystal Structures of Clay Minerals and their x-ray Identification" edited by G W. Brindley and G. Brown for the Mineralogical Society, is the most convenient standard reference. More recent work has been reviewed in a Mineralogical Society of American Monograph (Reviews in Mineralogy, Vol. 16, "Hydrous Phyllosilicates, Ed. S. W. Bailey, (1988)).
Included in the classes of clay minerals are smectite clays and kandite clays, the latter synonymously called diazeolites, serpentines, septochlorites and a variety of other specific names, depending on composition and layer orientation.
Smectites generally layered clays represented by the general formula: EQU (Si.sub.8).sup.iv (Al.sub.4).sup.vi.sub.O20 (OH.sub.4)
where the IV designation indicates an ion coordinated to four other ions, and VI designates an ion coordinated to six other ions. The IV coordinated ion is commonly Si.sup.4+, Al.sup.3+, or Fe.sup.3+ but could also include several other four coordinated ions, e.g., P.sup.5+, B.sup.3+, Ge.sup.4+, Be.sup.2+, etc. The VI coordinated ion is typically Al.sup.3+ or Mg.sup.2+, but could also include many other possible hexacoordinate ions, e.g., Fe.sup.3+, Fe.sup.2+, Ni.sup.2+, Cl.sup.2+, Li.sup.+, etc. The charge deficiencies created by substitutions into these cation positions are balanced by one or more cations located between the structured platelets. Water may be occluded between the layers and either bonded to the structure itself or to the cations as a hydration shell. Commercially available clays typical of this class include natural and synthetic variants of montmorillonite, bentonite, hectorite and various mica or mixed mica-montmorillonite mixed phases, including synthetic varieties, the most common being materials such as SMM (synthetic mica-montmorillonite) originated by the Baroid Corp. The pillaring of said materials is well established and characterized (e.g., U.S. Pat. Nos. 4,176,090; 4,248,739; and 4,271,043) and the state of the art has recently been reviewed by Vaughan (Amer. Chem. Soc. Symp. Ser. #368, p. 308-323, (1988)), particularly as the basic concept has been applied to layer compounds other than clays.
Kandite clays, also often called "kaolinite" minerals, are made up of 1:1 layers of tetrahedrally oxygen coordinated silicon, bonded to layers of octahedrally bound cations. In kaolinite, dickite and nacrite all of the tetrahedral cations are Si.sup.4+ and all of the octahedral cations are Al.sup.3+ ( so called dioctahedral forms ). However, in the serpentinite varieties, major substitution of Al.sup.3+ and Fe.sup.3+ occurs for Si.sup.4+ in the tetrahedral layer and a range of di- and trivalent cations substitutes for Al.sup.3+ in the octahedral layer. The ion Mg.sup.2+ is typically substituted for Al.sup.3+, although any of the Fourth Period Transition elements, e.g., V, Cr, Mn, Fe, Co, Ni, Cu, Zn, may serve as substitutes. In some locations they may form major deposits, as in the case of garnierite, a major nickel ore. (Table 1 lists examples of various mineral kandites illustrating the multiplicity of chemical compositions. ) A main characteristic of the class is that each member generally has a 1:1 neutral layer. The ideal stoichiometry of the dioctahedral (kaolinite) and trioctahedral (chrysotile) end-members may be given respectively as: EQU Al.sub.2 Si.sub.2 O.sub.5 (OH).sub.4 EQU and EQU Mg.sub.3 Si.sub.2 O.sub.5 (OH).sub.4
TABLE 1 ______________________________________ EXAMPLES OF KANDITE MINERALS KAOLINS-SERPENTINES VI IV ______________________________________ Kaolin Al.sub.2 Si.sub.2 O.sub.5 (OH).sub.4 Halloysite Al.sub.2 Si.sub.2 O.sub.5 (OH).sub.4 Chrysotile Mg.sub.3 Si.sub.2 O.sub.5 (OH).sub.4 Garnierite Ni.sub.3 Si.sub.2 O.sub.5 (OH).sub.4 Amesite (Mg, Fe).sub.2 Al Si Al O.sub.5 (OH).sub.4 Cronstedtite (R.sub.3-x.sup.2+, Fe.sub.x.sup.2+) Si, Fe.sup.3+ O.sub.5 (OH).sub.4 Greenalite (Fe, Mg, Mn).sub.3 Si.sub.2 O.sub.5 (OH).sub.4 ______________________________________
Mixed layers are common, as they are in all clay mineral types. However, Kaolin is quite unique as a mineral in that it exists in very high purity deposits in many parts of the world. The deposits in the states of Georgia and North and South Carolinas are particularly famous; the single layer thickness of this repeating sheet is about 7.2 .ANG.. When layers of water separate the 1:1 sheets, the repeat sheet dimension expands to about 10.1 .ANG., as is seen in the halloysite variety of kaolinite. Halloysite in comparison is a relatively rare mineral in large deposits and rapidly irreversibly loses water on exposure to air. PG,7
Sorption of various organic molecules, such as glycerol, have been reported for kaolinite and the 2:1 smectite clays. Organic molecules do not as a rule produce permanent pillaring between the clay layers, but form intercalates which may exhibit molecular sieve properties in some cases, as described by R. M. Barrer (Clays and Clay Minerals, v. 37, p. 385-95 (1989)) and Theng ("Formation and Properties of Clay Polymer Complexes, Elsevier Press" (1979)), but readily lose such properties on heating to moderate temperatures. Similarly, intercalation of organic salts, e.g., potassium acetate, has been reported and are reviewed by MacEwan and Wilson (ibid, p. 236) and Barrer (Zeolites and Clay Minerals p. 407, 1978). Permanent pillaring has not been reported in 1:1 kandite materials hitherto, and is the principal focus of this invention.
Various non-kandite clays have been expanded to produce pillared materials. For instance, smectite-type clays treated with large cationic inorganic complexes result in large pore materials useful as sorbents and catalysts. See Vaughan et al, U.S. Pat. No. 4,176,090, issued Nov. 27, 1979 (hereinafter Vaughan '090); Vaughan et al, U.S. Pat. No. 4,248,739, issued February 3, 1981 (hereinafter Vaughan '739); and Vaughan et al, U.S. Pat. No. 4,271,043, issued Jun. 2, 1981 (hereinafter Vaughan '043).
Vaughan '090 is directed to the production of stable interlayered clay compositions which are prepared by reacting smectite-type clays with polymeric cationic hydroxy metal complexes of metals such as aluminum, zirconium, or titanium and mixtures of those. The resulting pillared smectites have pillars of about 6 to 16 .ANG. between the clay layers. The resulting internal interconnected micropore structure (within the layer) has a majority of pores which are less than 30 .ANG. in diameter. Vaughan '090 makes no mention of using kandite-type clays as starting material.
Vaughan '739 discloses a method for producing pillared interlayered smectite clays which is an improvement upon the method for producing pillared materials disclosed in Vaughan '090. The improvement is said to lie in the use of an interlayering compound which is a polymeric cationic hydroxy inorganic metal complex having an increased molecular weight in excess of about 2,000 to about 20,000. The resulting clay products have interlayer spacing of about 6 to 16 .ANG. and have 80% of their pores less than about 40 .ANG. in diameter. Again, Vaughan, '734 makes no suggestion of using kandite-type clays as starting material.
Vaughan '043 teaches a variation on the processes and products of Vaughan '090 and Vaughan '739 which entails treating the calcined products disclosed in those latter patents with a basic solution of a compound such as ammonia. The products treated in this manner are disclosed to have an enhanced ion exchange capacity. Vaughan '043 makes no suggestion of using a kandite-type clay as starting materials. A complete review of these patents has been published elsewhere (Catalysis Today, V. 2, p. 187-98, (1988)).
The disclosure in U.S. Pat. No. 4,060,480, to Reed et al, issued Nov. 29, 1977, suggests treating generally smectite-type materials with a aluminum compound, drying the product and calcining it to produce a clay having an expanded interlayer separation. Reed et al suggest that a gibbsite-like layer may be formed by such a treatment. No mention is made, however, of treating a kandite material in such a fashion.
Various modified hydrotalcite like materials (sheet structures related to clays) have also been subject to "pillaring" in various ways (U.S. Pat. No. 4,454,244). These materials are single sheet octahedral structures having a positive layer charge, and are therefore subject to pillaring reactions with anionic species ( e.g., U.S. Pat. No. 4,454,244).
Recently several new layer structures have been successfully pillared with a variety of anionic, cationic and neutral inorganic polymeric molecules. They include various clays such as rectorite (European Patent Appln. 197,012) and tetrasilicia mica (Japanese Patent 56-142982); sheet silicic acids (European Patent Appln. 222,597; Deng et al, Chemistry of Materials, v. 1, p. 640-50, (1989)) which comprise a very large group of material (see F. Liebau for a review of such materials in "Structural Chemistry of Silicates" (Springer-Verlag (1985)); and zirconium phosphates (European Patent Appln. 159,756).
Several recent reviews of pillaring in clays and related sheet structures (Pinnavia, Science, 220, p. 365, (1983); Vaughan, "Catalysis Today", vol. 2, page 187-198, 1988; Vaughan, in "Perspectives in Molecular Sieve Science" Ed W H Flank et al, ACS Symp. Ser. 368, p. 308-23 (1988)) do not report kandite pillaring. Based on the viewpoint that pillaring requires a charge deficiency on the layer, the kandites would not be expected to be suitable pillaring substrates, as they are not recognized as having layer charge, and therefore have no ion exchange capacity. Reactivity and exchange in these materials is generally related to `OH` groups at the edges of the crystals. I have discovered that these can indeed be pillared to form porous materials. The proposed structure is shown in FIG. 1, which compares a kandite with a hydrated kandite and a pillared interlayered kandite (PILK).

Pillared interlayered kandite clay compositions


A cash box proximity switch arrangement is provided for public telephones and is mounted in an upper portion of a lower housing of the telephone above the vault area. The switch is contained in a sealed housing which prevents contamination from dirt, moisture and the like. A magnet can be arranged so as to provide a bi-stable magnetic circuit between the floor of the lower phone housing and a cash box lid attached to a cash box which has been installed in the vault area of the telephone housing.

The present invention relates to a public or pay telephone magnetic cash box switch configured to be mounted in an upper portion of the lower phone housing directly above the phone's vault area.
Conventional cash box switch arrangements are designed to detect the presence of the cash box either through mechanical or optical methods. These switches generally require the removal of the vault door and cash box for installation. For example, the arrangement in FIG. 1 is placed in the bottom of the vault area and uses an L-shaped arm to open and close a switch where the L-shaped arm is acted upon by the cash box. Such arrangements are both relatively delicate and are also relatively difficult to install.
We have recognized that the conventional switches possess other substantial disadvantages, chief among them being cost, unreliability due to fragile moving parts, susceptibility to tampering and corrosion, and temperature sensitivity. In the case of optical switches, interface electronics and/or a special chassis are required. Moreover, optical switches are affected by the physical condition of the cash box lid resulting from corrosion, dust, dirt, airborne contaminants and the like.
It is an object of the present invention to provide a low-cost magnetic cash box proximity switch which greatly simplifies installation, i.e., a switch which does not physically contact the cash box and which does not require the removal of the vault door and the cash box.
It is yet a further object of the present invention to allow for the switch to be installed by technicians who would normally not have keys which provide access to the vault area and cash box.
It is a still further object of the present invention to provide a cash box switch which utilizes non-contact magnetic techniques rather than the more conventional mechanical and optical methods so as to provide a relatively uncomplicated, reliable configuration.
In addition to being easily installed and reliable, the switch according to the present invention has the advantage of being tamper-proof, sealed and eliminating a need for power consumption.
Other advantageous features of the switch according to the present invention include a completely passive system which does not require any interface electronics or a special chassis, elimination of all moving parts except for a magnet, a switch which is downwardly compatible in place of a mechanical cash box switch, and a switch which can be retrofitted for use in existing 1D-style phone housings but can also be adapted to fit in 2D-style panel phone housing.
The foregoing objects and advantages have been achieved by providing a public telephone cash box switch using a magnet which is mountable in the portion of the lower housing directly above the phone's vault area. That is, the magnetic switch utilizes a bi-stable magnetic circuit in which the lower pole of the magnet is attracted to the phone housing with no cash box present and to the cash box lid when the cash box is installed. Proximity sensing avoids physical contact between the switch arrangement and the cash box lid.
More specifically, in a currently preferred embodiment, the switch arrangement includes a cap and a lower body containing a vertically oriented sealed reed switch and corresponding magnet for effecting the electrical switching function in which the corresponding magnet has a vertical travel of 0.050 inch. The magnet can be a Neodymium rare earth permanent magnet grade such as 33H with the distance between the reed switch contacts and the magnet chosen to minimize hysteresis in the operation of the reed switch.
The switch housing can be molded from a plastic or other suitable non-ferrous material selected for minimum friction, temperature stability, and moisture and humidity resistance. The housing unit is configured to be sealed with a compressible molded elastomer gasket to prevent dirt and moisture intrusion. The unit can be assembled with one or more screws or snapped together with interference fit posts and bores.
A flex circuit can be utilized for mounting the reed switch and making the electric connection to the wires while positioning and precisely retaining the reed switch within the switch housing. The above-mentioned elastomer sealing gasket can also be used to apply pressure to the top formed lead of the reed switch to assure its proper location within the housing.

Magnetic pay telephone cash box proximity switch