A wet electrophotographic printer includes a developing chamber communicating with an inlet of a first nip between a developing roller and a deposit roller to supply a liquid developer into the first nip therebetween, a developer storing chamber communicating with an inlet of a second nip between the developing roller and a metering roller to withdraw the liquid developer of a low density generated at the second nip during a development, and preventing the liquid developer of the low density from being supplied to the first nip, and a developer supply unit disposed below a partition to supply the liquid developer from the developer storing chamber into the developing chamber. The liquid developer of the low density generated at the second nip is not directly supplied to the first nip, but is supplied after being withdrawn to the developer storing chamber and mixed therein.

1. Field of the Invention
The present invention relates to a wet electrophotographic printer using a high density liquid developer, and more particularly, to a wet electrophotographic printer having a developing unit constructed so that an inlet of a nip between a developing roller and a metering roller communicates with a developer storing chamber to uniformly supply an appropriate high density liquid developer on a photosensitive body such as a photosensitive drum forming a visible developer image during a development.
2. Description of the Related Art
In general, an electrophotographic printer obtains a desired image by forming an electrostatic latent image on a photosensitive medium or photosensitive body such as a photosensitive belt or a photosensitive drum, developing the electrostatic latent image by using developers having predetermined colors, and transferring the developed electrostatic latent image to a paper. Electrophotographic printers are divided into wet type and dry type electrophotographic printers according to kinds of developers used therewith. The wet electrophotographic printer uses a liquid developer obtained by mixing a volatile liquid carrier with a powder type toner.
Since the wet electrophotographic printer using the liquid developer uses toner particles having a grain size less than about 0.5 to 5 μm, a higher quality image is obtainable for the wet electrophotographic printer than that of the dry electrophotographic printer using only the powder type toner in the development of the electrostatic latent image, and further, the wet electrophotographic printer prevents damage due to harmful toner dust. Therefore, the wet electrophotographic printer has gradually become popular to use.
However, the wet electrophotographic printer generally obtains an appropriate image density by using a low density liquid developer, which is below 3% solid. Accordingly, a complicated developer delivery system to sufficiently supply the liquid developer to developing regions of developing units and to collect the liquid developer is required to obtain the appropriate image density, thereby increasing a size of the developing unit and complicating the wet electrophotographic printer.
Further, an apparatus to control a density of the liquid developer is necessary to obtain the appropriate image density when replenishing the liquid developer due to variations of toner grains after the development.
Thus, the developer delivery system needs to be removed or to be simplified so as to prevent the wet electrophotographic printer from being oversized or being complicated. Accordingly, the wet electrophotographic printer using a high density liquid developer, which is over 3% solid, has been popularly used rather than a low density liquid developer, which is less than 3% solid.
FIG. 1 is a schematic view illustrating a general wet electrophotographic printer 1 using a high density liquid developer.
The wet electrophotographic printer 1 includes a photosensitive body 9 such as an organic photoconductive (OPC) drum, a laser scanning unit 11, a charging roller 12, a developing unit 13, a transfer belt 10 moving in a form of a caterpillar, primary and secondary rollers 21 and 22 rotating the transfer belt 10 in the form of the caterpillar, a first transfer roller 8 transferring a developer image to the transfer belt 10, a second transfer roller 23 transferring the developer image to a paper P, a fixing roller 25 fixing the developer image, and a cleaning blade 51 removing a residual developer image remaining on the transfer belt 10. The above-described elements of the wet electrophotographic printer sequentially perform an image formation process including a charging operation, an exposure operation, a development operation, a transfer operation and a fixation operation by mutual operations, to form a desired image on the paper P.
For color printing, the wet electrophotographic printer 1 includes four laser scanning units 11, and four developing units 13 each individually containing a high density liquid developer 48, each of which is of 3 to 40% solid and is of a different color, namely, the four individual high density liquid developers being, respectively, black, yellow, cyan and magenta in a color thereof.
Each of the developing units 13 includes a developing chamber 6 storing the high density liquid developer 48, a developing roller 7 positioned below the photosensitive body 9, a deposit roller 14 installed below the developing roller 7 to transmit an electric charge to the liquid developer 48 to form a charged developer layer on the developing roller 7, a metering roller 15 transmitting a predetermined voltage to the charged developer layer formed on the developing roller 7 by the deposit roller 14 to transfer a large volume of toner to the developing roller 7, and restricting the charged developer layer to have a predetermined amount or density (% solid) of the toner to supply into a nip between the developing roller 7 and the photosensitive body 9, and a cleaning roller 16 cleaning the developing roller 7.
The deposit roller 14 and the metering roller 15 serve to supply the predetermined toner amount or density of the charged developer layer into the nip between the developing roller 7 and the photosensitive body 9, regardless of the amount or the density of the solid, which is in a range of about 3 to 40% solid of the liquid developer 48.
To supply the liquid developer 48 to the developing chamber 6, disposed below each of the developing units 13 is a developer supply unit 28, 30.
Each of the developer supply units 28, 30 comprises a developer cartridge 28 connected to an inlet and an outlet formed, respectively, at a bottom and a side of the developing chamber 6 through connecting tubes 29 and serving as a developer storing chamber, and a pump 30 installed in each of the connecting tubes 29 positioned between the developer cartridge 28 and the inlet of the developing chamber 6.
Each of the developer cartridges 28 is coupled to a respective connecting tube 29 by a coupler (not shown) to facilitate during and exchange of the cartridge an attachment and a detachment thereof.
Operation of the wet electrophotographic printer 1 will now be explained.
According to a print command, an electric charge layer, namely an electrostatic latent image corresponding to an image to be printed is formed on the photosensitive body 9 by the charging roller 12 and the laser scanning unit 11 and then, a developer layer having a predetermined amount of toner formed on the developer roller 7 from the liquid developer 48 of the developing chamber 6 by the deposit roller 14 and the metering roller 15 is transferred to the electrostatic latent image, thereby forming a developer image.
Further, the liquid developer 48 is formed as a charged developer layer on the developing roller 7 due to an electric charge from the deposit roller 14, and formed as the developer layer having the predetermined amount of toner on the developing roller 7 by a predetermined voltage from the metering roller 15.
Further, the pump 30 supplies the liquid developer 48 into the developing chamber 6 from the developer cartridge 28 so that the developing chamber 6 overflows with the liquid developer 48 and the liquid developer 48, which is above a predetermined level, is withdrawn into the connecting tube 29 connected to the outlet of the developing chamber 6.
Accordingly, the liquid developer 48 is always maintained at the predetermined level in the developing chamber 6.
Thus, the developer image formed on the photosensitive body 9 by the developing unit 13 is transferred from the photosensitive body 9 to the transfer belt 10 by a voltage and a pressure of the first transfer roller 8 positioned inside the transfer belt 10. Since the transfer belt 10 rotates by the primary and secondary rollers 21 and 22, the image transferred to the transfer belt 10 is moved to the second transfer roller 23 and is subsequently transferred to the paper P by a voltage and a pressure of the second transfer roller 23.
The developer image transferred to the paper P is fixed to the paper P by the fixing roller 25 and a fixing backup roller 26, thereby forming the desired image.
After the developer image is transferred from the transfer belt 10 to the paper P, the transfer belt 10 continuously rotates by the primary and secondary rollers 21 and 22 and moves to the cleaning blade 51 installed to contact an image formation surface of the transfer belt 10 at a side of the primary roller 21. Further, remnants of the developer not transferred to the paper P (generally 90 to 98% of the developer is transferred to the paper P) are removed from the image formation surface of the transfer belt 10 by the cleaning blade 51 for succeeding image printing, and are collected in a used developer storing unit 52.
The transfer belt 10, from which the remnants of the developer are removed, repeats the aforementioned procedure to perform a subsequent electrostatic latent image formation and a subsequent development through the photosensitive body 9, the laser scanning unit 11 and the developing unit 13.
However, in the conventional wet electrophotographic printer 1, since the developer cartridge 28 of the developer supply unit 28, 30 is connected to the developing chamber 6 through the connecting tubes 29 to supply the liquid developer 48 thereto, the connecting tubes 29 may be clogged if the liquid developer 48 dries in the connecting tubes 29 and adheres thereto.
When the connecting tubes 29 are clogged as described above, the supply of the liquid developer 48 to the developing unit 13 is inefficient, thereby a quality of the developer image deteriorates. At worst, the developing unit 13 directly connected to the connecting tubes 29 is impossible to operate. In this case, all component parts including the developing unit 13 should be replaced by new component parts.
Further, to stably withdraw the liquid developer 48 overflowing from the developing chamber 6 into the developer cartridge 28 through the connecting tubes 29, the developer supply unit 28, 30 should be designed so that a free fall distance of the liquid developer 48 is maintained above a given range.
Further, since the developer cartridge 28 is attached and detached to the connecting tubes 29 by the coupler, exchanging of the developer cartridge 28 is troublesome, and if careless, the liquid developer 48 can flow out from the developer cartridge 28.
Since the pump 30 is relatively high-priced and used to supply the liquid developer 48 to the developing chamber 6, the manufacturing cost is increased.
Since each of the component parts, such as the developer cartridge 28, the developing unit 13 and the photosensitive body 9, which are disposed adjacent to each other, is constructed to be separately replaced, it is troublesome that the component parts are separately assembled and disassembled when problems related with the assembly as a whole occurs or that the component parts having almost identical life span are simultaneously replaced occurs.
To improve these problems, a wet electrophotographic printer 1′ having a single body developing unit 13′ in which a developing chamber and a developer cartridge are horizontally disposed and unified in a body so that a pump to supply a liquid developer is not required and replacement of individual component parts is not necessary as shown in FIG. 2.
In the wet electrophotographic printer 1′, a transfer belt 10′ is vertically disposed by primary and secondary rollers 21′ and 22′ installed in a longitudinally spaced-apart relation with each other to facilitate a disposal of remnants of developer remaining on the transfer belt 10′ after transferring a developer image to paper P and to prevent the remnants of the developer from moving to opposite ends of the primary roller 21′ and thereby contaminating the primary roller 21′, the transfer belt 10′ and other components of the wet electrophotographic printer 1′.
The wet electrophotographic printer 1′ includes a first transfer roller 8′ transferring a developer image to the transfer belt 10′, a second transfer roller 23′ transferring the developer image to a paper P, a fixing roller 25′ fixing the developer image, and a cleaning blade 51′ removing a residual developer image remaining on the transfer belt 10′. Further, remnants of the developer not transferred to the paper P are removed from the image formation surface of the transfer belt 10′ by the cleaning blade 51′ for succeeding image printing, and are collected in a used developer storing unit 52′.
The developer image transferred to the paper P is fixed to the paper P by the fixing roller 25′ and a fixing backup roller 26′, thereby forming the desired image.
To form a developer image of four colors, namely black, yellow, cyan and magenta, four image forming parts are installed at a side of the transfer belt 10′. Each of the image forming parts comprises a laser scanning unit 11′ horizontally disposed at a side of a photosensitive body 9′ to form an electrostatic latent image corresponding to an image to be printed according to an image signal, and the single body developing unit 13′ horizontally disposed below the photosensitive body 9′ to transfer a liquid developer 48′ to the electrostatic latent image formed on the photosensitive body 9′ to form the developer image.
As shown in FIG. 3, disposed about the photosensitive body 9′ are a discharging lamp 17, a corona charger 18, and a photosensitive body cleaner 19 having a cleaning blade 20 to clean the used remnants of the developer remaining on the photosensitive body 9′ after transferring the developer image from the photosensitive body 9′ to the transfer belt 10′, and a used developer reservoir 23.
The single body developing unit 13′ horizontally disposed below the photosensitive body 9′ comprises a developing chamber 6′ having a developing roller 7′, a deposit roller 14′, a metering roller 15′, and a cleaning roller 16′ installed therein; a developer storing chamber 28′ formed to horizontally extend and serving as a developer cartridge storing the liquid developer 48′; and a sponge roller 32 disposed to contact with a lower portion of partition 31 to divide the developing chamber 6′ and the developer storing chamber 28′ and to supply the liquid developer 48′ from the developer storing chamber 28′ to the developing chamber 6′.
When the sponge roller 32 rotates and is in compressive contact with the lower portion of the partition 31, the liquid developer 48′ absorbed by the sponge roller 32 in the developer storing chamber 28′ is moved into the developing chamber 6′, and then is discharged into the developing chamber 6′, so that the liquid developer 48′ is supplied from the developer storing chamber 28′ to the developing chamber 6′.
Thus, when the liquid developer 48′ is excessively supplied into the developing chamber 6′ by a rotation of the sponge roller 32, the liquid developer 48′ overflows a top end portion of the partition 31 and is withdrawn back into the developer storing chamber 28′.
In the wet electrophotographic printer 1′, since the single body developing unit 13′ has a structure in which the developing chamber 6′ and the developer storing chamber 28′ are unified in a body thereof, component parts are not separately assembled and disassembled in a replacement thereof, compared with the conventional wet electrophotographic printer 1. However, the wet electrophotographic printer 1′ presents a problem that the liquid developer 48′ having a high density stagnates in the developer storing chamber 28′ to form sediments of the toner contained therein on a bottom of the developer storing chamber 28′, since the developer storing chamber 28′ is formed to be horizontally and widely extended.
When the toner precipitates on the bottom of the developer storing chamber 28′, the density of the liquid developer 48′, which is formed as the charged developer layer on the developing roller 7′ due to an electric charge from the deposit roller 14′ in a vicinity of the deposit roller 14′ after moving from the developer storing chamber 28′ to the developing chamber 6′, is uneven according to a degree of precipitation of the toner, thereby a quality of the developer image formed during a development varies.
Therefore, to prevent the precipitation problem, an agitator needs to agitate the liquid developer 48′ in the developer storing chamber 28′, thereby manufacturing costs are increased.
Since the developer storing chamber 28′ is constructed to be horizontally and widely extended, a developer level of the liquid developer 48′ in the developer storing chamber 28′ may be lower than a top height of the sponge roller 32 even though the liquid developer 48′ is only slightly consumed.
In this case, when rotated, the sponge roller 32 absorbs air in the developer storing chamber 28′ and moves the absorbed air into the developing chamber 6′. Accordingly, when the sponge roller 32 is in compressive contact with the lower portion of the partition 31, the air absorbed by the sponge roller 32 in the developer storing chamber 28′ is discharged as air bubbles into the developing chamber 6′.
Thus, when the air bubbles form in the developing chamber 6′, the charged developer layer, which forms on the developing roller 7′ by the electric charge from the deposit roller 14′ in the vicinity of the deposit roller 14′, is uneven due to the air bubbles, thereby the quality of the developer image formed during the development varies.
Also, in the conventional wet electrophotographic printer 1′, since the metering roller 15′ is disposed in the developing chamber 6′, the liquid developer having a low density generated when the liquid developer 48′ is formed as the predetermined toner amount of developer layer on the developing roller 7 by a compression of the metering roller 15, may flow down from the metering roller 15 and may be directly supplied to the deposit roller 14′.
Thus, when the liquid developer of the low density is supplied to the deposit roller 14′, the density of the charged developer layer, which forms on the developing roller 7′ by the electric charge from the deposit roller 14′, is lower, thereby resulting in a problem that a density of the developed image is lower.


A method and system for managing multiple displays, including receiving a first indication to allow movement of an object between a first display and a second display, allowing movement of the object between the first display and the second display in view of the first indication, receiving a second indication to prevent movement of the object between the first display to the second display, and preventing movement of the object between the first display and the second display in view of the second indication.

On many computing platforms, the operating system allows for the use of multiple displays. A desktop is shown on the multiple displays, where the desktop is a graphical user interface with icons and menus that allows access to files and programs for a particular computer system. In addition, executing programs are placed in windows (i.e., application windows) that are also displayed and managed on the desktop. Objects, such as a cursor, windows, and icons, can be moved between the displays.
When objects can be moved between displays, interaction issues can be encountered at the window boundaries, which can be characterized by Fitts's Law. According to Fitts's Law, targets placed along an edge or corner of a screen shown on a display are ergonomically easier for users to access. On a single display system, the screen area 'stops' at all edges, so, rather than finely targeting a cursor to a specific pixel region of the display, the user can bounce the cursor against a 'wall' where the cursor will automatically stop. The edge is effectively a backstop. Targets, such as scroll bars, are often placed along the edge of an application window that could coincide with a screen edge to take advantage of this effect. However, in a multiple display system, the 'wall' may not be present on the edge of the screen where the cursor can be moved from the current display to another display. Therefore, the cursor continues to move onto the other display unless the user finely targets the target.
In an example of a display system with a left display and a right display, a cursor located on the left display is typically moved to the right display through the right edge of the left display. If a web browser application window with a scroll at the right edge of the window is maximized in the left display, then a user must finely target the scroll bar with a pointer or cursor. If the user attempts to merely bounce the cursor off the right edge of the display, the cursor will move onto the right display. At a minimum, this effect can be frustrating for a user. However, depending on the applications in use, undesired movement of the cursor onto a different screen can lead to disastrous results.


A large diameter rope having improved fatigue life on a sheave, pulley, or drum is disclosed. This rope includes a blend of HMPE filaments and liquid crystal polymer filaments selected from the group of lyotropic polymer filaments and thermotropic polymer filaments. The rope may be constructed as a braided rope, a wire-lay rope, or a parallel core rope.

In heavy lifting or mooring applications, such as marine, oceanographic, offshore oil and gas, seismic, and industrial applications, a standard rope is made from high modulus polyethylene (HMPE) filaments, such as those commercially available under the name of SPECTRA® from Honeywell Performance Fibers of Colonial Heights, Va. and DYNEEMA® from DSM NV of Heerlen, The Netherlands and Toyobo Company Ltd. of Osaka, Japan. These ropes are made into braided ropes or twisted ropes. For example, see U.S. Pat. Nos. 5,901,632 and 5,931,076. Therein is disclosed a braided rope construction in which filaments are twisted to form a twisted yarn, the twisted yarns are braided to form a braided strand, and the braided strands are then braided to form the braided rope.
The type of damage that leads to failure in these ropes is highly dependent on the service conditions, the construction of the rope, but most importantly the type of fibers used to manufacture the rope. When large diameter, high load-capacity ropes are pulled over a drum, pulley, or sheave, as occurs during heavy lifting, e.g. in lowering and raising packages from the seabed, two damage mechanisms are generally observed.
The first damage mechanism is frictional heat generated within the rope. This heat may be caused by the individual elements of the rope abrading one another; as well as, the rope rubbing against the drum, pulley, or sheave. This generated heat can be great enough to cause a catastrophic failure of the rope. This problem is particularly evident when the fiber material loses a substantial amount of strength (or becomes susceptible to creep rupture), when heated above ambient temperature. For example, HMPE fibers exhibit this type of failure; HMPE fibers, however, exhibit the least amount of fiber-to-fiber abrasion.
The second damage mechanism observed during over-sheave cycling of ropes is self-abrasion or fiber-to-fiber abrasion (i.e., rope fibers rubbing against one another). This type of damage is most often observed in ropes made from liquid crystal polymer (LCP) fibers. For example, aramids are known to be a poor material for general rope use because of self-abrasion; aramid fibers, however, are not generally susceptible to creep rupture.
In the studies leading to the instant invention, it was discovered that the primary occurrence of damaging abrasion was at the intersection between the subropes (or strands). Only, a little damage was observed within the subropes. Accordingly, a way to reduce the abrasion between the subropes was investigated.
In the prior art, jacketing the subropes is a known method for reducing abrasion between the subropes. Jacketing refers to the placement of a sleeve material (e.g., woven or braided fabric) over the subrope, so that the jacket is sacrificed to save the subrope. These jackets, however, add to the overall diameter, weight and cost of the rope without any appreciable increase in the rope's strength. The larger size is obviously undesirable because it would require larger drums, pulleys, or sheaves to handle the jacketed rope. In addition, rope jackets make visual inspection of the rope core fibers problematic because the jacket hides the core fibers. Therefore, while this solution was viable, it was considered unsatisfactory.
Accordingly, there is a need for a new rope solution, one without a jacket on the subropes that could be used in heavy lifting or mooring applications and have a reduced risk of failure. This rope solution would have to be resistant to creep rupture (unlike a rope made entirely from HMPE) and also resistant to self-abrasion (unlike a rope made entirely from LCP).
Small diameter rope (i.e., diameters less than or equal to 1.5 inches or 34 mm) made of blends of HMPE filaments and liquid crystal polymer filaments selected from the group of lyotropic and thermotropic polymer filaments are known. New England Ropes of Fall River, Mass. offers a high performance double braided rope (STA-SET T-900), consisting of blended SPECTRA® filaments and TECHNORA® filaments core within a braided polyester jacket, having a diameters up to 1.5 inches (34 mm). Sampson Rope Technologies of Ferndale, Wash. offers two yacht racing ropes: VALIDATOR SK, a double braid construction having a blended, urethane coated core of VECTRAN® filaments and DYNEEMA® filaments within a braided polyester jacket in diameters up to 0.75 inches (17 mm); and LIGHTNING ROPE, a twelve-strand single braid construction having a urethane coating and made from blended DYNEEMA® filaments and VECTRAN® filaments in diameters up to 0.625 inches (16 mm). Gottifredi Maffioli S.p.A. of Novara, Italy offers high performance halyards (DZ) of a double braid construction having a composite braid made of ZYLON® filaments and DYNEEMA® filaments within a jacket in diameters up to 22 mm.
In these small diameter ropes, the reason for blending HMPE and LCP fibers is to reduce creep elongation, and not to improve high-temperature fatigue life. For example, the yachting ropes cited above are used in halyards where dimensional stability (low to no creep) is critical for consistent sail positioning. HMPE ropes are more commonly used in small sailing ropes, however for the halyard application the creep of 100% HMPE fiber is considered prohibitive. Blending HMPE with LCP fibers greatly reduces the creep elongation in the product. Reduction of creep elongation in the core of these core/jacket products also prevents the core from bunching after elongating relative to the jacket. Blending the low-creep LCP fibers with the low-cost HMPE fibers also reduces the manufacturing cost of these products.
Moreover, all of those small diameter blended rope designs would have severe limitations if scaled to larger sizes. All are constructed with braided or extruded outer jackets. Although adequate in sizes ≦1.5 inches diameter, jacketed designs are less able to shed the tremendous amounts of heat that can be generated in larger ropes subjected to rapid bend cycling as over sheaves. Furthermore, jacketed designs limit the ability of the owner to assess damage done from heating or internal abrasion.
Finally, several of the prior art designs utilize parallel fiber, yarn, or strand as the core strength member. Designs that use parallel yarns or strands in the core are also subject to tensile overloads in the outer strands and compression kinking in the inner strands when subjected to bending over small radii sheaves and drums. This problem becomes more pronounced as rope size increases.


An n.sup.- -type InP buffer layer is formed on an n-type InP substrate. An n.sup.- -type InGaAs light absorbing layer is formed on the n.sup.- -type InP buffer layer. An n.sup.- -type InP cap layer is formed on the n.sup.- -type InGaAs light absorbing layer. A p-type InP region is formed in the InP cap layer. A layered electrode having a contact with the p-type InP region comprises a first layer made of an Au layer, a second layer made of a Ti layer or the like, a third layer made of a Pt layer or the like, and a fourth layer made of an Au layer. The first layer made of Au has a thickness of 1 to 500 nm. This structure improves an ohmic ability and a peel strength at a contact portion where an electrode is connected, and simplifies manufacturing steps.

1. Field of the Invention
The present invention relates to an electrode structure which improves an ohmic characteristic and a peel strength of a contact portion between a semiconductor and a metal electrode and which simplifies processing of the contact portion.
2. Description of the Related Art
Conventionally, a semiconductor device using III-V group compounds, such as a transistor, a diode, or the like, has a metal electrode for connecting the device to external electric circuits.
Electrode structures for the metal electrode stated above are divided broadly into two types, i.e., an alloy type and a non-alloy type. At first, an electrode structure of a semiconductor light receiving device used for optical communication will be explained below. There has been a rapid increase in demand for a semiconductor light receiving device in recent years.
FIG. 1 is a cross-sectional view showing an example of an InP/InGaAs-front-illuminated type semiconductor light receiving device (i.e., a photo diode).
The structure of this light receiving device will be explained as follows.
An n-type InP buffer layer 2 is formed on an n.sup.- -type InP substrate 1. An n.sup.- -type InGaAs light absorbing layer 3 is formed on the n.sup.- -type InP buffer layer 2. An n.sup.- -type InP cap layer 4 is formed on the n.sup.- -type InGaAs light absorbing layer 3.
A p-type impurity region 5 has a bottom portion positioned in the InGaAs light absorbing layer 3. The impurity region 5 is formed, for example, by selectively diffusing Zn (zinc) as p-type impurities into the InP cap layer 4.
In a light receiving device having the structure stated above, a so-called non-alloy type electrode is formed on a surface of the p-type impurity region. The non-alloy type electrode has a layered structure made of a Ti (titanium) layer 22, a Pt (platinum) layer 23, and an Au (gold) layer 24. The Ti layer 22 has a contact with p-type impurity region 5. Since the Ti 22 does not substantially react with InP contained in the p-type impurity region 5 to make an alloy, the non-alloy electrode stated above is formed.
A so-called alloy type electrode is formed on an InP substrate 1. The alloy type electrode has a layered structure made of an AuGe layer 25, Ni (nickel) layer 26, and an Au layer 27. The AuGe layer 25 has a contact with the InP substrate 1. The AuGe layer 25 reacts with InP of the InP substrate 1 to make an alloy, through a thermal treatment, and thus, an alloy type electrode which achieves an ohmic contact is formed.
In a non-alloy type electrode having a contact with the p-type impurity region 5, Ti layer 22 serves as a wiring layer for a mount or a wire-bonding, and a Pt layer 23 serves as a barrier 22 for preventing interactive diffusion between the Ti layer 22 and the Au layer 24.
The light receiving device stated above is mounted on a ceramic carrier, for example, by means of AuSn soldering, with the surface of the Au layer 27 being interposed as a connection surface. A wire of an AU line is bonded to the Au layer 24. A connection is thus obtained between the above light receiving device and external electric circuits.
However, the above light receiving device has defects as follows.
In a non-alloy type electrode having a contact with the p-type impurity region 5, a Schottky-barrier is easily formed on an interface between the Ti 22 layer and the p-type impurity region 5. As a result, a problem arises in that the Ti layer 22 and the p-type impurity region 5 cannot achieve a sufficient ohmic contact with each other, and the contact therebetween incurs a high resistance.
In addition, the Ti layer 22 which serves as a contact metal does not form an alloy together with InP contained in the p-type impurity region 5, but simply has a contact with the p-type impurity region 5. A peel strength is therefore insufficient between the Ti layer 22 and the p-type impurity region 5, so that the entire layered electrode consisting of layers 22 to 24 is easily peeled off from the light receiving device when an Au wire is bonded onto the Au layer 24. Consequently, the above light receiving device has a problem that the manufacturing yield and the reliability are low.
Meanwhile, as a conventional electrode structure, well-known is one in which an electrode having a contact with the p-type impurity region 5 is of an alloy type electrode in place of a non-alloy type electrode.
This alloy type electrode has, for example, a layered structure made of Au, AuZn, and Au or made of Au, AuCr, and Au, and Au has a contact with an InP cap layer 4. Since Au reacts with InP contained in the p-type impurity region 5 to form an alloy, through a heat treatment, so that an alloy type electrode is formed which can realize an ohmic contact.
Also, this alloy type electrode is characterized in that dopants, such as Zn, Cr, and the like, are introduced into an interface between the electrode and a semiconductor to achieve an ohmic contact which reduces a contact resistance between the electrode and the semiconductor.
However, Au tends to significantly react with InP to form an alloy layer having a high resistance. Therefore, there may be a case that impurities of Zn, Cr, and the likes do not effectively serve as dopants to lower the contact resistance, if a large amount of Au which is a main component of the contact metal reacts with InP to form an alloy.
A reaction of a large amount of Au with InP, as stated above, proceeds as time elapses. Therefore, there is a problem that, if an alloy type electrode is adopted in a planar type device whose electrode and p-n junction are close to each other, as shown in FIG. 1, the p-n junction is destroyed as the alloy-formation proceeds between Au and InP, and the reliability of the device is significantly degraded.
Further, in case of a conventional electrode structure, a p-type electrode (Au/AuZn/Au, Au/AuCr/Au, or the like) having a contact with a p-type impurity layer 5 and an n-type electrode (Au/AuGe/Au or the like) having a contact with an InP substrate 1 must be formed independently from each other.
Recently, developments have been made to a light receiving device of a structure in which a p-type electrode and an n-type electrode are formed on one common surface of a semiconductor substrate. In this kind of light receiving device, there is a problem that the process for forming electrodes is complicated and as a result manufacturing costs are increased, if the p-type and n-type electrodes have different structures.

Semiconductor device having layered electrode


A database system that has a plurality of nodes determines whether each node has a first version of database software. A broadcast message is sent from a first node of the database system to other nodes of the database system. In response to the broadcast message, at least each of at least some of the other nodes starts a software module to perform a task with respect to the database software executable in each node.

A database system stores collections of logically related data. One common type of database system is the relational database management system (RDBMS), which stores data in tables (or relations) that are arranged as rows and columns. To access data in a database system, requests according to a standard database query language are submitted to the database system to retrieve, update, or to delete data, as well as to manipulate various objects in the database system, including tables, definitions of tables, and so forth.
In certain applications, such as data warehousing applications, large amounts of data are stored in a database system. To provide rapid access of data contained in the database system, some database systems are implemented as parallel database systems. An example of a parallel database system is the TERADATA® database system from NCR Corporation. Some parallel database systems include a plurality of nodes, with each node having one or multiple processors. The nodes of the parallel database system are coupled by a network to enable intercommunication among the nodes. Tables are distributed across the nodes such that different portions of each table can be accessed concurrently in response to queries submitted by users.
An issue associated with a parallel database system having multiple nodes is that different versions of software may be stored on different nodes. Database administrators are continually updating database software to improve performance of database systems. To ensure that each of the nodes of a parallel database system is running the same version of software, a reconciliation procedure is usually performed to check the version of database software running on each node.
To perform the reconciliation of software versions running on the nodes of a parallel database system, inter-node communications are usually performed. Conventionally, in a reconciliation procedure, inter-node communications use point-to-point connections (e.g., TCP/IP or Transmission Control Protocol/Internet Protocol connections) between any two nodes. If a parallel database system has a large number of nodes (e.g., hundreds or thousands of nodes), the point-to-point connections that have to be established between nodes in a conventional parallel database system can take up a large amount of time. Thus, the reconciliation procedure, which is usually performed at system restart, can take a relatively long period of time to run.

Starting database software in response to a broadcast message


The device comprises a tubular housing with two jackets and a container filled with the liquid component of a drug. Within the inner jacket of the housing, close to the closed end thereof, is a chamber containing the powdered components of a drug. A needle for piercing the stopper which closes the container enables the interior of the container to be put in communication with the chamber so as to allow the liquid component to flow out and consequently mix with the powdered component. The subsequent advance of the container into the housing, with the consequent penetration of the piston into the container, causes the further flow of the liquid component into the chamber carrying the drug solution to the exterior of the device generally like a syringe. Its use as a supplier of infusions is also foreseen.

The present invention relates to devices for the administration of drugs.
More particularly, the present invention constitutes an improvement in the solution described in the prior Italian Industrial utility model application 15156-B/89 and the corresponding DE-U-9 003 505.
The application in question relates to a device for the administration of drugs, particularly liquids, comprising a double-walled housing which is open at one end and closed at the other by an end wall, in which a needle is fixed and extends substantially the entire length of the housing. The inner jacket of the housing is threaded at least at its open end so as to receive a threaded spigot of a piston applied in the form of a stopper to the open end of a cylindrical container housing the liquid to be administered. The piston has an axial bore closed by a diaphragm which can be pierced by the needle when the spigot of the piston is screwed into the inner jacket. By forming the cylindrical container axially into the said housing it is possible to supply the said liquid product. The entirety is generally like a syringe; it is also possible to envisage the use of this same structure as a device for supplying infusions.
The present invention attempts principly to improve on this prior solution so as to extend its use to the supply of drugs constituted by a liquid and a powder which must be dissolved in the liquid before use. At present the usual method used with drugs of this type provides for a liquid to be drawn up from a phial into a syringe and then for the liquid to be injected into another phial containing the powdered drug and then--after the drug has dissolved--for the solution to be taken up again in a syringe before the injection proper can be effected: a sequence of operations which is rather complicated and must be carried out with extreme care.
According to the present invention, the object is achieved by means of a device for the administration of drugs having the characteristics claimed specifically in the claims which follow.

Device for the administration of drugs, particularly two-component drugs


A test circuit board adapted to be used on memory slot is provided. Each memory slot of a board to be tested is connected to one test circuit board. A plurality of the test circuit boards form an in-series connection therebetween. A test access port (TAP) controller is connected electrically to the board to be tested and one of the test circuit boards so that the memory slots, which are connected to the test circuit boards, may be tested at the same time.

Technical Field
The present invention relates to a circuit board, and particularly to a circuit board adapted to be used on memory slot where a first joint test activity group (JTAG) connection interface and a second JTAG connection interface are provided to form an in-series connection between test circuit boards.
Related Art
For the currently available the test technologies regarding a memory slot in a board to be tested, only a single test circuit board is tested in most cases, and only a single memory slot may be tested. In this case, the issue of absence of a test signal coverage is generally arisen, lending to an unfavorable effect on the test in a production process.
In view of the above, it may be known that there has long been existed in the prior art of the absence of the test signal coverage on the memory slot in the board to be tested. Therefore, there is quite a need to set forth an improvement means to settle down this problem.

Test circuit board adapted to be used on memory slot

INVENTEC (PUDONG) TECHNOLOGY CORPORATION


A radiator is arranged behind an engine, a selective catalytic reduction apparatus, and a connecting pipe. A partition wall partitions first and second accommodation spaces. The engine, the selective catalytic reduction apparatus, and the connecting pipe are arranged in the first space. The radiator is arranged in the second space. A reducing agent tank is arranged behind the partition wall. A reducing ejection apparatus attached to the pipe ejects reducing agent into the pipe. A reducing agent hose connects the tank and the apparatus. The hose has a boundary portion positioned at a boundary between the first and second spaces. A height position of the boundary portion is between top and bottom sections of the connecting pipe. The boundary portion and the reducing agent ejection apparatus are arranged on a left or right side of a center line extending in a front and back direction of the partition wall.

1. Field of Invention
The present invention relates to a work vehicle.
2. Background Information
In recent years, the mounting of an exhaust processing apparatus for processing exhaust onto a work vehicle has become desirable. The exhaust processing apparatus is connected to an engine through a connecting pipe in order to process the exhaust from the engine. A selective catalytic reduction apparatus may be used as the exhaust processing apparatus. The selective catalytic reduction apparatus reduces the nitrogen oxide (NOx) in the exhaust.
The selective catalytic reduction apparatus processes the exhaust using a reducing agent such as aqueous urea. As a result, it is necessary to arrange a reducing agent tank which retains the reducing agent in the work vehicle. However, there is a possibility that the reducing agent may freeze in a low temperature environment. Accordingly, it is desirable for the reducing agent tank to be arranged to be kept at a temperature where freezing does not occur. For example, in the hydraulic excavator according to Japan Patent Laid-open Patent Publication No. 2009-184558, a reducing agent tank is arranged inside a counterweight which is arranged in the rear section of the vehicle.


A method of charging a floating gate in a nonvolatile memory cell comprises bringing a substrate channel within the memory cell to a first voltage, bringing a control gate to a programming voltage, and floating the substrate channel voltage while the control gate is at the programming voltage. Memory devices include state machines or controllers operable to perform the described method, and operation of such a state machine, memory device, and information handling system are described.

A variety of computer systems and electronic devices use memory that is not volatile, or does not lose its content when power is disconnected. These nonvolatile memories can be reprogrammed, read, and erased electronically, and are particularly well suited to storing information such as music in digital audio players, pictures in digital cameras, and configuration data in cellular telephones. Such memory is commonly known as flash memory, named in part because a flash operation is used to erase the content of a block of data before it is reprogrammed, and is packaged for consumer use in products such as CompactFlash memory cards, USB flash memory drives, and other such devices.
Flash memory comprises a number of cells, each of which typically stores a single binary digit or bit of information. A typical flash memory or nonvolatile memory cell comprises a field effect transistor having an electrically isolated floating gate that controls electrical conduction between source and drain regions of the memory cell. Data is represented by a charge stored on the floating gate, and the resulting conductivity observed between the source and drain regions.
The floating gate resides in an insulating material between a second gate known as a control gate and the channel region of the memory cell. Electrons stored on the floating gate insulated from the control gate and the drain and source by an insulating oxide layer partially cancel out or modify an electric field provided via a voltage signal applied the control gate, resulting in a change in the effective threshold voltage (Vt) of the memory cell. When the memory cell is read by placing a specified voltage on the control gate, the electrical impedance between the source and drain of the device will either allow or not allow current to flow, depending on the presence of a charge on the floating gate and the effective Vt or threshold voltage of the memory cell. The presence or absence of current above a threshold level is sensed, and used to determine the state of the memory cell, resulting in a one or zero value being read.
Memory cells are typically arranged in a two-dimensional array of rows and columns, where the rows are coupled via a wordline conductor and the columns are coupled via a bitline conductor. The wordline and bitline conductors are used during data read and write functions to either select certain wordlines for reading or to select words and bits for writing.
The memory cells themselves are further subject to the resistance and capacitance of the bitlines and wordlines coupled to the memory cell for proper operation and communication with a memory controller. Device features, such as variation in the oxide layer thickness between the floating gate and the conduction region between the source and drain can also cause variation in the threshold voltage and other operating parameters of such a flash memory cell. Also, close physical proximity of memory cells in the memory array can result in coupling between floating gates, further influencing the operation of the memory cells.
For these and other reasons, there is a need for methods and devices to operate and program nonvolatile memory devices.

This patent is subject to a terminal disclaimer.


A method of electrically interconnecting conductors, such as electrical components to a printed circuit board. A plurality of first and second conductors are provided which are discrete and at least one of which is made of soft magnetic material that can be temporarily magnetized. The plurality of first conductors are arranged in a predetermined arrangement on a surface of a substrate. An adhesive layer comprised of a mixture is disposed on the surface of the substrate and over the plurality of first conductors. The mixture is comprised of an adhesive and a predetermined concentration of conductive metal particles made of soft magnetic materials that can be temporarily magnetized. The adhesive has a predetermined viscosity which allows the conductive metal particles to be suspended within the adhesive. The mixture is substantially insulating at the predetermined concentration of conductive metal particles. The plurality of second conductors are arranged above the adhesive layer in vertical alignment with the individual conductors of the plurality of first conductors. The adhesive layer is heated to reduce the viscosity of the mixture. A magnetic field is applied such that the conductive metal particles within the heated adhesive mixture are gathered by the magnetic field to produce a higher concentration of conductive metal particles between the aligned individual conductors of the plurality of first and the second conductors, and provide electrical interconnection therebetween, and to produce a lower concentration of conductive metal particles in adjacent areas of the layer; and hardening the adhesive layer.

The present invention relates to a method of interconnecting conductors, and more specifically, to a method utilized for electrically interconnecting an electrical component, such as an IC package, having a plurality of conducting terminals to a printed circuit board (PCB).
A conventional method for interconnecting an IC package to a PCB is to use soldering techniques. Since the pins of the IC package are arranged with very close spacings, 30 mil in general, precise dot deposition is required to place solder only upon the pins and not therebetween. Furthermore, soldering techniques require temperatures high enough to melt the solder so that both the IC package and the printed circuit board must be able to withstand such high temperatures.
A number of methods therefore have been proposed to eliminate the use of solders in electrically interconnecting IC packages to PCBs. A U.S. Pat. No. 4,820,376 issued to Lambert et al, discloses the use of a conductive polymer interconnect material (CPI) having a plurality of chains of electrically conducting particles. A sheet made of the CPI material can be disposed onto the surface of a PCB. When the disposed sheet is pressed by the pins of an IC package, the conducting particle chains therewithin electrically connect the pins to the PCB. Since the conducting particles chains are randomly distributed and are also fixed within the CPI material, they can not be moved so as to be gathered at specific positions.
In U.S. Pat. Nos. 4,667,401, 4,720,740, and 4,868,637 issued to Clements et al; there are disclosed the use of an adhesive of dielectric polymeric resin having a viscosity in the range of 10,000 cps to 40,000 cps and 20 wt % to 25 wt % conductive metal particles. The adhesive is coated uniformly onto the surface of a PCB and afterwards an IC package is pressed onto the coated layer so that portions of the adhesives that are distributed on the conductive strips of the PCB are pressed by the pins of the IC package. The pressed portions are thereby reduced in volume such that the concentrations of conductive metal particles at these points are increased to 45-50 percent by weight. In accordance with a TABLE 1 given in the specification of U.S. Pat. No. 4,667,401, the resistance value of an adhesive having 20 wt % to 25 wt % conductive metal particles is greater than 10.sup.14 .OMEGA. and that of adhesive having 45 wt % to 50 wt % conductive metal particles is less than 1.OMEGA.. As a result, although the pins of the IC package are submerged into a same layer of adhesive, electrical connections are established between the pins of the IC package and the conducting strips of the PCB and while there are still excellent insulations among the pins of the IC package.
The method according to the patents of Clements et al; however, suffers from high failure rate of electrical connections since the establishment of an electrical connection requires that the concentration of conductive metal particles exceed a threshold value (somewhere between 40 wt % and 45 wt %), the denser the better. To concentrate the conductive metal particles merely by pressing the adhesive is somewhat a rough method that can not guarantee high successful rates of electrical connections.
Jin et al, in their U.S. Pat. No. 4,737,112 disclose an electrical interconnection which is established by means of an anisotropically conductive, composite layer medium comprising electrically conductive particles in a nonconductive matrix material. Magnetic field is applied to align the conductive particles to form electrically conducting chains.
Hutcheson in his U.S. Pat. No. 4,170,677 dislcoses a method of making electrical connections between large-scale integrated circuit boards or the like using a plastic adhesive charged with conductive particles. The method includes the steps of: coating the board with a conductive-whisker charged plastic adhesive, placing another board on the adhesive coating; applying an aligning field to make the conductive whisker align perpendicular to the boards, and hardening the adhesive while the field is applied. However, as can be seen from FIG. 2 of Hutcheson's patent, applying magnetic field can only make the conductive whiskers align perpendicular to the boards, but not gather. Therefore, the method of Hutcheson is the same as that of Jin et al; and can not guarantee high successful rates of electrical connections.

Method of electrically interconnecting conductors

Industrial Technology Research Institute


A device for securing a graft in a bone tunnel includes an anchoring member having a graft supporting surface. The anchoring member is configured to be positioned within the bone tunnel distal of an interference member with the graft retained by the graft supporting surface and extending proximally from the anchoring member. The anchoring member has an engaging surface for engaging a distal end of the interference member to limit movement of the graft relative to the interference member.

This invention relates to a graft anchor for securing a graft in a bone tunnel.
A torn ligament is a common injury. One way to treat the injury is to replace the ligament with a soft tissue or synthetic graft, formed from a ligament or tendon tissue or synthetic material. A surgeon drills a tunnel in the bone, and positions one end of the graft in the tunnel. An interference screw is positioned in the tunnel adjacent the graft to urge the graft against the wall of the tunnel.
According to one aspect of the invention, a device for securing a graft in a bone tunnel includes an anchoring member having a graft supporting surface. The anchoring member is configured to be positioned within the bone tunnel distal of an interference member with the graft retained by the graft supporting surface and extending proximally from the anchoring member. The anchoring member has an engaging surface for engaging a distal end of the interference member to limit movement of the graft relative to the interference member.
Embodiments of this aspect of the invention may include one or more of the following features.
The engaging surface is an end face of the anchoring member. The end face has a coupling member configured to interface with the interference member. The coupling member is a protruding nib sized to fit within an opening in an end of the interference member. The nib is located in a center portion of the anchoring member. Alternatively, the nib is located off-center of the anchoring member.
The graft supporting surface is constructed to receive a graft looped around the anchoring member, and is formed by an exterior surface of the anchoring member. The anchoring member is a generally planar structure including four sides, a top face, and a bottom face forming the engaging surface. The graft supporting surface includes at least one of the four sides and the top face. The top face is indented. The four sides are flat.
The graft supporting surface includes a first indented surface defined by a first side of the anchoring member, a second indented surface defined by a second opposing side of the anchoring member, a third indented surface defined by a third side of the anchoring member, and a fourth indented surface defined by a fourth side of the anchoring member. Alternatively, the third and fourth sides of the anchoring member are not part of the graft supporting surface, and are convex surfaces.
The anchoring member defines a bore for receiving a guide wire. The bore is located in the center of the anchoring member. Alternatively, the bore is located off-center. The nib is located circumferentially about the bore.
In another aspect, an anchoring member for securing a graft in a bone tunnel includes a generally planar structure having a first side, an opposing second side, a distal end, and a proximal end face. The first side defining a first indentation for receiving the graft and the second side defines a second indentation for receiving the graft. The end face includes a protruding nib configured to fit within an opening in an end of an interference member. The structure defines a bore for receiving a guide wire. The anchoring member is configured to be positioned within the bone tunnel distal of an interference member with the protruding nib interfacing with the interference member and with the graft looped around the distal end of the structure and retained in the first and second indentations. The anchoring member limits movement of the graft relative to the interference member.
According to another aspect, the invention features a method for securing a graft in a bone tunnel. The method includes providing an anchoring member having a graft supporting surface; looping the graft over the anchoring member so that the graft is retained by the graft supporting surface; inserting the anchoring member and graft into the bone tunnel; and inserting an interference member into the bone tunnel adjacent the graft and proximal of the anchoring member so that the anchoring member engages a distal end of the interference member to limit movement of the graft relative to the interference member.
Embodiments of this aspect of the invention may include one or more of the following features.
The anchoring member is loaded onto a guide wire. Inserting the anchoring member includes inserting the anchoring member and graft into the bone tunnel with the guide wire. The anchoring member is loaded onto a distal end of the guide wire such that the anchoring member abuts a ledge defined by the guide wire. The ledge limits proximal movement of the anchoring member relative to the guide wire.
Inserting the interference member, e.g., an interference screw, into the bone tunnel includes distally advancing the interference member over a guide wire, and abutting the distal end of the interference member against an end face of the anchoring member. The end face includes a protruding nib and an end of the interference member is placed over the nib.
According to another aspect of the invention, a device for securing a graft in a bone tunnel includes an anchoring member, an interference member, and a guide wire. The anchoring member has a graft supporting surface. The anchoring member is configured to be positioned within the bone tunnel with the graft retained by the graft supporting surface and extending proximally from the anchoring member. The anchoring member defines a first bore of a first diameter. The interference member defines a second bore of a second diameter larger than the first diameter. The guide wire has a first region and a second region of a different diameter than the first region. The first and second regions of the guide wire define a shelf therebetween. The diameter of the second region of the guide wire is larger than the diameter of the first bore. The first region is insertable into the first bore with the shelf abutting the anchoring member and the interference member is insertable over the guide wire to abut the anchoring member.
Embodiments of this aspect of the invention may include a guide wire having locating mark for indicating the position of the interference member within the bone tunnel.
According to another aspect of the invention, a device for securing a graft in a bone tunnel includes an anchoring member and a guide wire. The anchoring member has a graft supporting surface. The anchoring member is configured to be positioned within the bone tunnel with the graft retained by the graft supporting surface and extending proximally from the anchoring member. The anchoring member defines a bore. The guide wire includes a first region and a second region of a different diameter than the first region. The first and second regions of the guide wire define a shelf therebetween. The diameter of the second region is larger than a diameter of the bore. The first region is insertable into the bore with the shelf abutting the anchoring member.
Among other advantages, the invention is easy to use and provides a reliable way of avoiding the graft from slipping between the interference screw and the side of the bone hole. As a result, the invention helps assure that the graft will remain securely in place even when tension is applied to it. Because the graft is directly retained by the graft supporting surface of the anchoring member, there is no need to take more elaborate measures (such as attempting to retain the graft with suture) to help prevent the graft from slipping. Furthermore, the surgeon can properly position the interference member in the bone relative to the anchoring member by simply using markings on the guide wire.


A solar liquid heater employing a solar absorber flat plate collector combined in a self-contained unit with an integral liquid storage tank insulated to prevent reversible heat flow and embodying an air flow path over the top of the collector, around the liquid storage tank, across the bottom of the collector and again back across the top of the collector in a closed loop path.

In recent years, the rapid expansion of the world's population coupled with the accelerated technological development of large sectors of the world has produced a dramatic increase in the demand for energy in all forms including fuels and electricity for heating, lighting, transportation and manufacturing processes. The construction of hydroelectric facilities and the development of fossil fuel resources has continued at a rapid rate, but it becomes increasingly evident for a number of reasons that these efforts are inadequate to keep pace with the demands of the growing population.
Flat plate solar collectors with air and/or fluid flow grooves and tubes have been known with one known flat plate collector being described in the World Book Encyclopedia, (copyrighted 1963 ). This encyclopedia describes the flat plate collector as being made of metal and glass with one or more layers of glass laid over a blackened metal plate. Air spaces are provided between the layers of glass. Air or water passes through tubes under the metal plate to remove the collected thermal energy. The layers of glass in cooperation with the blackened metal plate acts as a heat trap, letting in the sun's rays but keeping most of the heat from escaping again.
A major disadvantage of the known flat plate collectors is that they need auxiliary apparatus to function as a system, i.e., they are not self contained. To be self contained and function as a system, the flat collector must embody an integral liquid storage reservoir embodied in an effective insulated enclosure and it must be kept insulated and isolated from any opportunity to radiate heat to the atmosphere or associated lower temperature bodies.
Even though the known flat plate collectors are efficient in collecting solar energy and are very simple and inexpensive to construct, they have not been developed to their full potential.


A check of the observance of prescribed transmission bit rates in an ATM switching equipment occurs using counter devices (RAM1, ALU) working according to the "leaky bucket" principle. These are individually allocated to virtual connections via the switching equipment (VA). The momentary counter readings of these counter devices are respectively decremented by a variable count value only upon arrival of a message cell of the respective virtual connection. This variable count value is proportional to the time difference between the arrival time of the respective message cell and the arrival time of the message cell of the same virtual connection that immediately preceded it. The transmission bit rates determined for the virtual connections are thereby allocated to defined bit rates classes. On the basis of this allocation, an individual proportionality factor that is utilized for the duration of the existence of the respective virtual connection for the calculation of the variable count value is calculated for each of the virtual connections on the basis of this allocation.

The present invention is directed to a method and circuit arrangement for checking the observance of prescribed transmission bit rates of the individual virtual connections for asynchronous transmission of message cells of fixed length during the course of virtual connections in a switching equipment.
Such a method, also referred to as a "leaky bucket" method is disclosed by European Patent 0 381 275. This publication only teaches that a constant value that, for example, corresponds to a power of two is used as a proportionality factor in the formation of the variable count value for the decrementation of the momentary counter readings of the individual counter devices. However, what is not taught is how such a proportionality factor is to be in fact defined for the individual, virtual connections.

Method and arrangement for checking the observance of prescribed transmission bit rates in an ATM switching equipment


Embedded DRAM cells within an ASIC having a pass transistor with a gate oxide having a thickness equal to the thickness of the gate oxide of the logic core. This allows the embedded DRAM cell to be activated by signals having voltage levels equal to the voltage levels created by the logic core. If the gate oxide has a thickness that is equal to the gate oxide thickness of the peripheral circuits, a signal provided by the word line voltage generator has voltage levels equal to those provided by peripheral circuits, and signal provided by the bit line voltage generator has voltage levels equal to those provided by logic circuits within the logic core. If the gate oxide has a thickness that is equal to the thickness of the gate oxide of the logic circuits, a signal provided by the word line voltage generator has voltage levels equal to those provided by the logic circuits, and the bit line voltage generator has voltage levels equal to those provided by the logic circuits.

1. Field of the Invention
This invention relates to integrated circuits containing logic circuits and embedded Dynamic Random Access Memory (DRAM). More particularly, this invention relates structures of pass transistors within the embedded DRAM such that the processing of the pass transistor is equivalent to that of transistors that form the logic core.
2. Description of the Related Art
Application Specific Integrated Circuits (ASIC) contain sections of circuitry that implement digital logic, provide peripheral circuits to interface to system function, memory, and analog functions. As DRAM has been embedded into an ASIC, the process for constructing the ASIC has become more complex.
Refer now to FIGS. 1a, 1b, and 1c for discussion of the structure of an ASIC containing a logic core and an embedded DRAM array. FIG. 1b illustrates an embedded DRAM cell. The embedded DRAM cell has a pass transistor Mp 105 and a cell capacitor Cc 102. The first plate of the cell capacitor Cc 102 is connected to the drain of the pass transistor Mp 105. The second plate of the cell capacitor is generally connected to the substrate biasing voltage source Vss. The second plate of the cell capacitor may alternatively be connected to a biasing voltage source that is one half the voltage level of the power supply voltage source VDD.
The source of the pass transistor Mp 105 is connected to a bit line voltage generator VBIT. The bit line voltage generator VBIT generates signals that have the appropriate voltage levels that are used to charge or discharge the cell capacitor Cc 102. Generally the voltage level of the power supply voltage source VDD is used to represent a logical 1 and the ground reference level represents a logical 0.
The gate of the pass transistor Mp 105 is connected to the word line voltage generator VWORD. The word line voltage generator VWORD activates the pass transistor Mp 105 when brought to a voltage level greater than the threshold voltage level Vt of the pass transistor Mp 105. If bit line voltage generator VBIT and thus the source of the pass transistor Mp 105 is at the voltage level of the power supply voltage source VDD, the word line voltage generator has to have a voltage level that is from 1.5-2 times the voltage level of the power supply voltage source.
A basic logic circuit is shown in FIG. 1c. The N-channel MOS transistor M1110 and the P-channel MOS transistor M2115 are configured as a CMOS inverter. By appropriate placement of additional N-channel and P-channel MOS transistors within the circuit, more complex logic functions can be created. Further, the inverter can be constructed as a driver or receiver within peripheral circuits of the logic core by appropriate design of the transistor parameters and geometry.
The structure of a DRAM cell is shown in FIG. 1a. The pass transistor Mp 105 is formed on the semiconductor substrate 100 by first implanting an N-type material to a lightly doped concentration into the surface of the substrate 100 to form a deep N-well 125. A P-type material is then implanted into the surface of the semiconductor substrate 100 within the area of the deep N-well 125 to form the P-well 130. The N-type material is then diffused to highly doped concentration into the P-well 130 to form the source 135 and drain 140 of the pass transistor Mp 105.
The cell capacitor Cc 120 is then formed by techniques known in the art, such as stacked capacitor or trench capacitor formation.
The transistors M1115 and M2110 of the logic circuit are formed concurrently with the pass transistor Mp 105. The N-type material is implanted to the lightly doped concentration to form the N-well 175. The N-type material is implanted to a highly doped concentration to form the source 155 and drain 160 of the N-channel transistor 110.
The P-type material is implanted to a highly doped concentration into the surface of the semiconductor substrate 100 to form the source 180 and the drain 185 of the P-channel MOS transistor 115.
A thin gate oxide is formed on the surface of the semiconductor substrate 100 in the areas 165 and 190 above the channel region between the source 155 and the drain 160 of the N-channel transistor 110, and the source 180 and the drain 185 of the P-channel transistor 115.
Since the voltage level of the word line voltage generator VWORD is as much as twice the voltage level of the power supply voltage source VDD, the gate oxide 145 above the channel between the source 135 and the drain 140 of the pass transistor Mp 105 is deposited as a thick gate oxide to prevent excess stress within the thick gate oxide 145. Having multiple thicknesses of the gate oxides 145, 165 and 190 complicates the fabrication process of an ASIC that includes embedded DRAM thus increasing cost. Further, having multiple steps of gate oxide formation causes a higher defect density with the gate oxide.
Typically, the thick oxide is formed to a thickness of from approximately 70 xc3x85 to approximately 150 xc3x85, while the thin oxide has a thickness of from approximately 30 xc3x85 to approximately 70 xc3x85 for the logic circuit and the peripheral circuits. Generally the peripheral circuits have a higher operating voltage, and therefore require the thickness of the thin oxide and the thick oxide to be thicker than that of the logic circuit.
U.S. Pat. No. 5,668,035 (Fang et al.) discusses a method for fabricating an ASIC with an embedded memory array and a logic core. The method is described for forming a thin gate oxide for the logic core, while providing a thicker oxide for the memory cells having a boosted word line architecture. The method avoids applying photoresist directly to the gate oxide, and thereby prevents contamination. A first gate oxide is formed on the device areas on the substrate. A first polysilicon layer is deposited and patterned leaving portions over the memory cell areas. The first gate oxide is removed over the logic core areas, and is replaced by a thinner second gate oxide. A second polysilicon layer is deposited and patterned to remain over the logic core areas. The first and second polysilicon layers, having essentially equal thickness, are coated with an insulating layer. The FET gate electrodes for both the logic and memory cell areas are simultaneously patterned from the first and second polysilicon layers to complete the DRAM structure up to and including the gate electrodes.
U.S. Pat. No. 5,702,988 (Liang) describes a method of forming semiconductor logic devices and memory devices on a single semiconductor substrate. The memory devices that may be formed include nonvolatile memory, DRAM and/or SRAM. The method begins by forming triple-well structure of N-well regions, P-well regions, and P-well in N-well regions on a semiconductor substrate. Field isolation regions are then formed. A cell is formed for each memory device in the memory regions. A channel implant is performed in the substrate for each of the logic and memory devices. A gate and gate oxide is formed individually for each of the logic and memory devices. LDD (Lightly Doped Drain) active regions and heavily doped source/drain regions are formed adjacent to each gate. Additional memory structures are formed, such as a DRAM capacitor. An interlevel dielectric and contact openings therein are formed. One or more metal layers are subsequently deposited over the interlevel dielectric layer and in the openings to make contact to the contact regions.
U.S. Pat. No. 5,712,201 (Lee et al.) teaches a semiconductor fabrication process in which both DRAM and logic device structures are integrated on a single silicon chip. The process features combining process steps for both device types, while using only a single level of polysilicon for both a high capacity DRAM cell, as well as for a CMOS logic core. The high capacity DRAM cell is composed of an overlying polysilicon storage gate structure, a thin dielectric layer, and an underlying doped semiconductor region.
U.S. Pat. No. 5,547,893 (Sung) describes a method for simultaneously fabricating memory cells, CMOS devices, and bipolar devices on a semiconductor substrate using a minimum additional number of process steps and process complexity. The method of Sung simultaneously fabricates a CMOS DRAM and a vertical bipolar transistor with a low collector resistance and a N+ polysilicon emitter without using an epitaxy layer.
U.S. Pat. No. 5,600,598 (Skaveland et al.) teaches an embedded DRAM within an ASIC process. Skaveland et al. has a structure for storage of charge that avoids charge leakage from the storage capacitor to the substrate, and eliminates the requirement for a continuous voltage VBB. The DRAM charge storage structure is comprised of a p-channel access FET in an nxe2x88x92 doped well of a pxe2x88x92 doped substrate, a pxe2x88x92 channel charge storage capacitor, conductive apparatus connecting a plate of the capacitor to a drain of the FET, and apparatus for applying a word line voltage to a gate of the FET.
Skaveland et al. further teaches a DRAM charge storage structure that is comprised of a charge storage capacitor structure connected between a high voltage source V and a source-drain circuit of a storage cell access FET, the gate of the storage cell access FET being connected to a word line. The cell access FET is comprised of first and second p doped regions separated by a channel and contained in an nxe2x88x92 doped region of a pxe2x88x92 doped substrate. The capacitor is comprised of an FET having a gate conductive region insulated from and disposed above the intrinsic nxe2x88x92 doped channel region. The gate conductive region of the capacitor is connected to the second p doped region of the FET spaced from the conductive region. A third p doped region is contained in the nxe2x88x92 doped channel region adjacent the edge of the conductive region. An n doped region is contained in the n doped region spaced from the third p-doped region. A high voltage Vpp is applied to the n doped region and to the third p doped region. The bit line is connected to the first p doped region. Voltage is applied from the word line to a gate of the cell access FET that is boosted from the word line voltage Vdd.
U.S. Pat. No. 5,214,603 (Dhong et al.) teaches a folded bit line DRAM cell that includes a trench capacitor and a planar-configured access transistor. The access transistor is stacked over the capacitor and has a first terminal connected to the capacitor. Dhong et al. further describes a folded bit line DRAM cell that includes a vertically oriented access transistor having one terminal formed on the upper extent of a contact to the trench capacitor, to provide optimum electrical connection to between the access transistor and the contact of the trench capacitor.
U.S. Pat. No. 5,436,477 (Hashizume et al.) describes a DRAM memory cell where the transfer gate transistors are formed on a main surface of a semiconductor substrate. The transfer gate transistors have impurity regions for serving as source/drain regions. A first interlayer insulating film having a substantially flat upper surface is formed to cover the transfer gate transistors. The first interlayer insulating film is provided with contact holes reaching the impurity regions. Plugs are formed in the contact holes. Capacitors are only formed on the flat upper surface of the first interlayer insulating film. Lower electrodes of the capacitors and the plugs are electrically connected with each other through barrier layers.
U.S. Pat. No. 5,606,189 (Adan) describes a floating electrode capacitor (FEC) DRAM that occupies a small area on the substrate and which nevertheless has a great capacitance. Adan provides a dynamic RAM comprising (a) a pair of MOS transistors formed side by side on a substrate, (b) a trench formed in the substrate between Source/Drain active regions A and B adjacent to each other at one end of each of the MOS transistors, and (c) a stack capacitor comprising a first electrode layer connected to the impurity region A, capacitor insulating layer and a second electrode layer connected to the impurity region B the layers being formed one over another and embedded in the trench in the order mentioned.
An object of this invention is to provide an array of embedded DRAM cells within an ASIC having a pass transistor with a gate oxide having a thickness equal to the thickness of the gate oxide of the logic core.
Further, it is an object of this invention to provide an embedded DRAM cell in an array embedded within an ASIC that is activated by signals having voltage levels equal to the voltage levels created by the logic core.
To accomplish these and other objects an embedded DRAM cell is comprised of a cell capacitor to retain digital data as electrical charge and a pass transistor. The cell capacitor has a first plate connected to a biasing power supply voltage source. The pass transistors has a drain connected to a second plate of the cell capacitor, a source connected to bit line voltage generator, a gate connected to a word line generator, and a gate oxide. The gate oxide separates the gate from a channel region that separates the drain from the source. The gate oxide has a thickness that is equal to a thickness of gate oxide of either the peripheral circuits or the logic circuits of the logic core of the application specific integrated circuit.
If the gate oxide has a thickness that is equal to the gate oxide thickness of the peripheral circuits of the logic core, a signal provided by the word line voltage generator has voltage levels equal to voltage levels of signal provided by peripheral circuits within the logic core. A signal provided by the bit line voltage generator has voltage levels equal to voltage levels of signals provided by logic circuits within the logic core. The thickness of the gate oxide for the peripheral circuits and thus the gate oxide of the pass transistor is from approximately 30 xc3x85 thick to approximately 70 xc3x85 thick.
The signals of the word line voltage generator have a high level of from approximately 3.1 volts to approximately 5.5 volts. The signals of the bit line voltage generator have a high level of from approximately 2.3 volts to approximately 2.6 volts.
However, if the gate oxide has a thickness that is equal to the thickness of the gate oxide of the logic circuits, a signal provided by the word line voltage generator has voltage levels equal to voltage levels of signals provided by the logic circuits within the logic core. The signal provided by the bit line voltage generator has voltage levels equal to voltage levels of signals provided by the logic circuits within the logic core. The thickness of the gate oxide for the logic circuits and thus the gate oxide of the pass transistor is from approximately 30 xc3x85 thick to approximately 70 xc3x85 thick.
The signals of the word line voltage generator have a high level of from approximately 1.5 volts to approximately 3.3 volts. The signals of the bit line voltage generator have a high level of from approximately 1.5 volts. to approximately 3.3 volts.

Process technology architecture of embedded DRAM

Taiwan Semiconductor Manufacturing Company


A multi-garment, re-usable plastic hanger having a clip configuration wherein a recess is formed in a web connecting a first garment retaining clip and a second garment retaining clip to a longitudinally extending body of the hanger to provide spring action which accommodates the stress placed on the web without breaking.

Molded plastic garment hangers are widely used for the purpose of shipping and displaying garments. Garment hangers of that type may either be simply constructed as molded plastic structures incorporating a unitary or metal central hook adapted to be suspended from a suitable support, such as a garment rack or the like, or with a hanger body portion having arms extending in opposite directions from the base of the hook portion so as to facilitate a garment to be suspended therefrom. When needed for specific use, the opposite or distal ends of the body portion or arms may be members to enable the attachment of various kinds of garments thereto, such as underwear, slips, brassieres, swimwear, multiple garments, and the like.
A wide variety of such garment hangers are presently known. Typically, such garment hangers have a hook portion elevated above a horizontally-extending body portion, as shown in U.S. Pat. Nos. 4,828,155; 3,463,369; and U.S. Pat. No. Des. 246,817. In order to grasp a garment effectively, clips, grips, slots or hooks (collectively referred to herein as "clips") are placed at the ends of the body portion of the hanger. Such prior art hangers are exemplified by U.S. Pat. Nos. 4,623,079; 4,629,102; 4,892,237; 5,065,916; and 5,129,557.
U.S. Pat. Nos. 4,623,079 and 4,629,102 disclose a hanger having an elevated hook member, a hanger body having horizontally extending arms and, respectively, resilient grips and clips of a U-shaped configuration located at the end of each arm. The U-shaped configuration includes first and second members, which are connected to each other; the second member also being connected to the hanger body. The U-shaped garment engaging grip or clip has a double-flex mechanism to prevent breakage of the grip or clip when a garment is resiliently engaged.
U.S. Pat. No. 4,892,237 discloses a plastic garment hanger having a hook, a body bar extending longitudinally from said hook, said body bar terminating at each end in a pair of arms, one above and one below the body bar, which form garment receiving slots. A third arm creates a downwardly opening slot at the end of the body. The shape of the arms is such that the mouth or open end of the slot is narrower than the upper or inner end of each clip. Adjacent the blind end of the garment receiving slot, the slot is deepened to form a pocket which is recessed downwardly into the body. At the entrance of the pocket a tongue from the upper flange of the body bar is provided. The tongue divides the pocket. Additionally, a finger which extends upwardly and outwardly at an angle from the upper flange of the body bar is provided. The finger is spaced inwardly a short distance from the clip.
U.S. Pat. No. 5,065,916 discloses a plastic garment hanger having garment retaining clip ends formed with downwardly and outwardly included support elements from which upper and lower retaining elements extend in a "T" and are provided directly with the formations engaging the garments in respective channels. The channels are defined by surfaces having interdigitating arrays of teeth. The clip configuration is intended to overcome the deficiencies ordinarily associated with clips having flexible bent back fingers.
U.S. Pat. No. 5,129,557 discloses a plastic garment hanger having a hook, a body bar extending longitudinally from the hook and wing portions terminating each end of the body bar. Each wing portion defines a first channel extending upwardly. The body bar defines a second channel in intersecting relation with the first channel. The second channel is inclined at an acute angle with respect to the first channel. Positioned along the first channel are a series of generally semi-circular projections which function to impede the movement of the garment, i.e., panty, intended to be suspended therefrom.
U.S. Pat. No. 5,236,109 discloses a plastic, multi-garment hanger which includes a slot extending upwardly from the edge of the body member between a vertically oriented clip and a horizontally oriented clip. The slot provides for the displacement of a portion of the vertically oriented clip and/or the horizontally oriented clip thereby reducing the level of stress concentrated at the upper, inward edge of vertical oriented clips and the connecting portion of the horizontally oriented clips of typical multi-clip hangers. However, while the slot is taught to provide additional flexibility, applicant notes that the portions of the vertically oriented and horizontally oriented clips of U.S. Pat. No. 5,236,109 are necessarily thinner in construction which weakens such clips and reduces their strength.
Each of the above-described prior art hangers (with the exception of the hanger provided by U.S. Pat. No. 5,129,557) is provided with a clip arrangement for the retention of light-weight, two-piece garments, such as panties and brassieres. Each type of clip arrangement is provided with some level of flexibility necessary for the insertion of the garment in the clip.
The clip arrangement of the hanger disclosed in U.S. Pat. Nos. 4,623,079 and 4,629,102, described above, has generally a U-shaped configuration, the flexible free end of which can be deflected in two directions.
The clip arrangement of the hanger disclosed in U.S. Pat. No. 5,065,916, described above, has a T-shaped clip configuration to firmly engage garments. It will be appreciated that the channel of the vertical clip extends at its upper end into an inwardly extending lateral slot so that a bend is applied to the waistband which can be somewhat stretched to better secure the waistband.
The clip arrangement of the hanger disclosed in U.S. Pat. No. 4,892,237, described above, is designed so that the flexible arms forming the garment receiving channels provide a clamping zone to prevent the inadvertent release of the garment retained therein.
However, a combination of different types of clothing are not easily positioned on or removed from these hangers. Since many of the clip arrangements of the prior art hangers are not constructed to flex numerous times without breaking and provide sufficient resistance to deflection at the time the garments are suspended therefrom and/or are removed. Additionally, these hangers do not effectively clamp a combination of different types of clothing especially garments which have very thin straps and thick waistbands.