A solid state image pickup device includes light-receiving circuitry having a plurality of light-receiving cells arranged in a matrix. Apparatus is provided for reading and storing electrical signals output by the light-receiving circuitry, and includes (1) a first memory for reading bright signals out of the light-receiving cells arranged in a row for storing the bright signals for a horizontal scanning period, (2) a second memory for reading dark signals out of the light-receiving cells arranged in the row for storing the dark signal for the horizontal scanning period, and (3) a readout circuit for reading the bright and dark signals stored in the first and second memories simultaneously. A removing circuit is provided for removing fixed pattern noise by simultaneously processing the bright and dark current signals read out from the first and second memories. Preferably, this removing circuit comprises a differential amplifier. Also, the light receiving cells and the reading and storing apparatus are preferably provided on a single semiconductor substrate.

1. Field of the Invention
The present invention relates to a solid state image pickup apparatus and, more particularly, to a solid state image pickup apparatus having a plurality of photoelectric transducer elements each having a capacitor electrode on a control electrode region of a corresponding semiconductor transistor.
The present invention also relates to a solid state image pickup apparatus for selectively reading out a plurality of sensor signals and, more particularly, to a solid state image pickup apparatus capable of eliminating unnecessary components such as variations in dark signals and drive noise.
2. Related Background Art
A TV or SV camera with an image sensor such as a CCD or MOS sensor has an aperture mechanism. Photoelectric transducer apparatuses each having a TV or SV camera with an automatic aperture mechanism are described in Japanese Patent Disclosure (Kokai) Nos. 12759/1985 to 12765/1985.
This photoelectric transducer apparatus includes a photosensor having a plurality of sensor cells each having a capacitor formed on a control electrode of a corresponding semiconductor transistor.
In the conventional photoelectric transducer apparatus described above, noise is often mixed an output signal read out from the photosensor cells due to variations in dark voltage generated in the cells within an arbitrary store time.
An output signal corresponding to the dark current component generated within the photosensor cell is prestored as reference optical information in an external memory in a conventional apparatus. A reference output signal derived from the reference optical information and an output signal from the actual optical information read out from the photosensor cell are compared with each other, and the output signal of the actual optical information is corrected, thereby eliminating the noise component caused by the dark voltage.
In the conventional photoelectric transducer apparatus described above, in order to constitute a photoelectric transducer system, the resultant system is undesirably complicated since a separate external circuit including a noise removal memory is required.
When a conventional photoelectric transducer apparatus is applied to a video camera or the like, the following problem occurs. When photoelectric transducer cells are arranged in a two-dimensional matrix and scanned in the vertical and horizontal directions, holes are stored in the base of each photoelectric transducer cell in a store mode upon reception of strong light. The base potential is forward-biased with respect to the emitter potential. The potential of a vertical line connected to the emitter electrode of each photoelectric transducer cell receiving strong light is increased to cause a blooming phenomenon. In order to prevent this, it Is proposed that the vertical lines are grounded for a period excluding the readout operation, thereby refreshing the charge overflowing onto the vertical line. However, the vertical line can be grounded for only the horizontal blanking period, i.e., about 10 .mu.s. Therefore, the charge overflowing onto the vertical line during the horizontal scanning period still causes the blooming phenomenon.
In the readout mode, when imade signals are sequentially output by horizontal scanning after they are stored in a vertical line, a dummy signal is generated during the storage of the signal in the vertical line. In other words, a smear phenomenon occurs.
In addition, the period for performing the refresh operation in the conventional apparatus is about 10 .mu.s in the horizontal blanking period. The refresh time is short and result in incomplete refreshing and hence an after image phenomenon.
Furthermore, assume that when the conventional photoelectric transducer apparatus is used as a single-plate type solid-state imaging device in a color television video camera, color filters are deposited or adhered onto the pixels. If an alignment scheme such as a Bayer alignment is used to form vertical lines in units of colors, i.e., R, G, and B, at least two vertical lines are required for the pixels of each column. In this case, since the vertical line portion does not serve as the photosensitive portion, the light-receiving area is reduced by the two vertical lines for each column. In other words, the opening of the aperture is undesirably reduced.
In a conventional photosensitive transducer apparatus, negative and positive voltages are required to bias an output amplifier, and the constitution is thus complicated. It is difficult to read out the signal component without degrading the frequency characteristics.
FIG. 15A is a schematic circuit diagram of a conventional solid-state image pickup apparatus.
Referring to FIG. 15A, signals from sensors S1 to Sn are respectively amplified by amplifiers A1 and An, and transistors T1 to Tn are sequentially turned on. A dot sequential output appears on an output line 101A. The dot sequential signal is amplified by a buffer amplifier 102A, and the resultant signal appears as an output signal Vout.
In the conventional image pickup apparatus described above, variations in input/output characteristics of the amplifiers A1 to An are included in the sensor signals as the dot sequential output appearing on the output line 101A. As a result, steady pattern noise undesirably occurs.
FIG. 15B shows a schematic arrangement of another conventional photoelectric transducer apparatus.
Referring to FIG. 15B, signals read out from photosensors S1 to Sn are temporarily stored in storage capacitors C1 to Cn. Transistors T1 to Tn are sequentially turned on at timings of a scanning circuit SH, and the readout signals sequentially appear on an output line 101A and are output to an external device through an amplifier 102A.
In the above photoelectric transducer apparatus, however, unnecessary components such as dark signals and drive noise of the photosensors are undesirably included.
Drive noise is defined as noise generated when a photosensor is driven to read out a signal. The drive noise components are noise caused by manufacturing variations such as element shapes and smear caused by element isolation and depending on radiation amounts.
The dark signal is defined as a dark current of a photosensor and greatly depends on accumulation time and temperature of the photosensor.
This drive noise will be described in detail. Variations in drive capacity of a drive element for driving a photoelectric transducer element and variations in capacity of a photoelectric transducer element cause variations in a leakage component of drive pulses. These variation components as an information signal are superposed on a necessary photoelectric transducer signal and are read out. The cause of generation of drive noise will be described below.
FIG. 15C is a schematic view of a photoelectric transducer element described in Japanese Patent Laid-Open Gazette No. 12764/1985, FIG. 15D is a timing chart of drive pulses for driving the photoelectric transducer element shown in FIG. 15C, and FIG. 15E is a chart showing the base potential of the photoelectric transducer element.
Referring to FIG. 15C, the photoelectric transducer element includes a base accumulation type bipolar transistor B, a drive capacitor Cox for reverse-or forward-biasing the transistor B in response to a drive pulse .phi.r, and a refresh transistor Qr. The transistor B has junction capacitances Cbc and Cbe. It should be noted that Cox, Cbc, and Cbe are referred to as capacitances or capacitors hereinafter, as needed. The capacitances Cox, Cbc, and Cbe are added to obtain a charge storage capacitance Ctot.
The operation of the photoelectric transducer element will be described below.
Assume that the initial value of a base potential VB is given as V0. When the drive pulse .phi.r is set at a potential V.phi.r at time t1, a voltage Va is applied to the base of the transistor B through the drive capacitor Cox. In this case, the voltage Va can be represented as follows: ##EQU1##
When the drive pulse .phi.rh is set at a high potential at time t2, a transistor Qr is turned on.
When the transistor B is forward-biased, the base potential VB is abruptly decreased. A time interval TC between time t2 and time t3 is a so-called refresh time interval.
The drive pulse .phi.r is set at zero at time t3, and a voltage -Va is added to the base voltage VB, so that the base voltage VB is set at V2. This reverse-biased state is the accumulation state.
The above description was confined to one photoelectric transducer element. However, a line or area sensor has a large number of photoelectric transducer elements. The capacitances of the capacitors Cox, Cbc, and Cbe between a large number of photoelectric transducer elements vary by a few fractions of 1%. For example, if the following conditions are given: EQU Cox=Cbc=Cbe.perspectiveto.0.014 pF, and V.phi.r=5 V
and the capacitance variation is 0.2%, then a variation .DELTA.Va in capacitance division voltage Va is about 3 mV.
The variation .DELTA.Va can be reduced by refreshing. However, when the refresh mode is changed to an accumulation operation mode (time t3), the variation occurs again to produce .DELTA.Vb. The variation .DELTA.Vb does not satisfy the relation .DELTA.Vb=-66 Va, and the correlation cannot be established therebetween according to test results.
The above fact is assumed to be derived from different bias voltage dependencies of Cbc and Cbe.
In the next read cycle, when the transistor B is forward-biased, the variation in base potential thereof is approximated as follows: EQU .DELTA.V.sup.2 .perspectiveto..DELTA.Va.sup.2 +.DELTA.Vb.sup.2 +2K.DELTA.Va.DELTA.b (2)
for K equal to -1 or more. As a result, the variation .DELTA.V becomes steady drive noise of about 4 to 5 mV.
The variation in leakage component of such a drive pulse (to be referred to as drive noise hereinafter) is eliminated according to the following conventional technique. That is, the above drive noise is stored in a memory means and is read out and subtracted from the signal read out from the sensor to obtain a true information signal.
The conventional drive noise correction technique described above causes a bulky, expensive photoelectric transducer element which does not have any industrial advantage.
In particular, in case the numbers of elements arranged in the horizontal direction and vertical direction are five hundred respectively, an area sensor requires 250,000 photoelectric elements arranged in a matrix form. In addition, when the resolution of the sensor is also taken into consideration, a memory of several megabits is required.
The unnecessary signals such as drive noise and a dark signal pose serious problems when an image of a dark object is to be picked up, i.e., image pickup at a low intensity. In the low-intensity image pickup mode, an information signal level is low and accordingly the S/N ratio is degraded. As a result, image quality is degraded. In order to improve image quality, the unnecessary signals must be reduced.
As described above, however, the dark signal primarily depends on temperature and charge accumulation time, although the drive noise rarely depends thereon. If these unnecessary signals are to be eliminated, the dark signal must be separated from the drive noise and a correction coefficient must be determined, thus requiring a large-capacity memory. As a result, signal processing is complicated and expensive, and an image pickup apparatus is undesirably bulky.


The production of NH3, Urea, UAN, and DAP, starting from inherently intermittent renewable energy, such as photovoltaic and wind power, is made economical by use of molten salt thermal energy storage (ESS) and water electrolyzer (WE) concentrated oxygen. The process inputs and equipment apply air; hydrogen-containing fuel, such as biomass; WE (concentrated O2 and H2 producing); thermal ESS equipped with a turbine and generator to steady the electricity input to the WE; and an ammonia plant. The thermal ESS enables minimally sized process equipment including, the WE, the air separation unit and less hydrogen storage. The concentrated oxygen from the water electrolyzer uniquely enables high-temperature thermal ESS input, water and CO2 collection and other fertilizer products, including Urea, UAN and DAP. DAP production is facilitated by using WE high-purity O2 oxidation and ammonium nitrate is similarly facilitated by anhydrous NH3 oxidation.

The best placement of photovoltaic power modules is often in locations that are inland that may have various ammonia producing restrictions, such as, process water may be costly or scarce, natural gas and naphtha may not be available, and ambient temperature may be high (35 to 50° C.).
Ammonia price premiums, between coastal and inland due to over-ground transport cost are significant, for example, USA Midwest 405 USD/MT NH3 (due to over-ground transport costs) compared with US Gulf Coast prices of 250 USD. The shipment cost of ammonia does not necessarily decrease with ammonia prices, so that during low ammonia price market times, the shipment costs becomes a greater percentage of the overall cost burden.
A second degree of restriction is, if photovoltaic (PV) and/or wind power is used to make ammonia they are intermittent power sources (short-term dependent supply) as are most renewables. When wind is the primary source, often ambient temperature is not an issue, so solar power combined with wind may provide more stability, but the intermittent nature of wind power is restrictive for use in producing chemical products.
Recently an analysis done by the Kenyan government and a Japanese multinational looked into installing a local fertilizer plant in Kenya was put on hold, because it was decided that it did not make economic sense due to Kenya's lack of the raw materials to make ammonia.
Production of CO2-negative-or-neutral ammonia would empower African economies that lack natural gas and petroleum and have fragile water supplies.

Renewable energy produced ammonia, apparatus, method and materials


Systems, apparatuses and methods for erasing hard drives. A system, which can be configured as a stand alone and portable apparatus, includes a control device configured to support an erase module. The erase module is configured to erase a hard drive such that data erased from the hard drive is forensically unrecoverable. The system further includes a user interface and at least one drive bay configured to provide communication between a hard drive and the control device.

The present invention relates to computer and data security, particularly to an apparatus and method for erasing data contained upon magnetic data storage media.
Computer and data security are important concerns for individuals, businesses and governments. Particularly, secure techniques for erasing or otherwise disposing of electronically stored data are growing concerns. U.S. Patent Application Publication No. 2004/0252628, which is commonly assigned to Ensconce Data Technology, Inc. and is incorporated herein by reference, describes the developing importance of secure data destruction for individuals, businesses and governments. Legislation has also pushed the importance of data security to the forefront. To comply with federal regulations, companies now need to completely and reliably eliminate all sensitive data on hard disk drives prior to disposing of or reusing the drive. Specifically provisions of the Financial Services Modernization Act (2003)(Gramm-Leach-Bliley), the Fair and Accurate Credit Transaction Act of 2003 (FACT Act), the Corporate and Criminal Fraud Accountability Act of 2002 (Sarbanes-Oxley), and the Health Insurance Portability and Accountability Act (HIPPA) all contain data security requirements. The regulations under these acts set requirements for securely handling sensitive data.
In response to the increasing need for computer and data security, techniques for erasing or destroying electronically stored data have been developed. One such development is data eraser software, which is intended to make deleted files unrecoverable as well as eliminate the extraneous data that is created and stored by many applications, especially those involving the Internet. Such software is run on the computer containing the hard drive that stores the information to be deleted. The software causes an over-write of certain data on the hard drive. However, the computer's BIOS and/or components of the hard drive itself may interfere with the software, preventing complete erasure of data on the hard drive. For example, the BIOS of the computer and/or hard drive components may prevent data on certain areas of the hard drive from being erased. Therefore, the data is not securely erased or destroyed and can often be recovered by known forensic data recovery techniques.
Accordingly, what is needed is an apparatus and method for erasing data contained on a storage medium, such as a hard drive, such that it is unrecoverable by known forensic data recovery techniques.


A casino game having a horse-racing theme. The casino game encompasses several playable races. A horseshoe playing surface is provided, which has a plurality of horse positions and a betting area inscribed thereon.

The competitive racing of horses is one of humankind's most ancient sports, having its origins among the prehistoric nomadic tribesmen of Central Asia who first domesticated the horse some 6,000 years ago. For thousands of years, horse racing flourished as the sport of kings and nobility.
Horse racing is the second most widely attended U.S. spectator sport, after baseball. Horse racing is also a major professional sport in Canada, Great Britain, Ireland, Western Europe, the Middle East, Australia, New Zealand, South Africa, and South America.
By the time humans began to keep written records, horse racing was an organized sport in all major civilizations from Central Asia to the Mediterranean. Both chariot and mounted horse racing were events in the ancient Greek Olympics, and the sport was popular in the Roman Empire.
Horse racing began to become a professional sport during the reign of Queen Anne in the early 18th century, when match racing gave way to races involving several horses on which spectators wagered. Racecourses were built all over England, offering increasingly large purses to attract the best horses. These purses in turn made breeding and owning horses for racing profitable.
British settlers brought horses and horse racing to the New World, with the first racetrack laid out on Long Island in the 17th century. Gambling on racehorses grew significantly over time. By 1890, more than 300 tracks were operating across the United States. Thoroughbred tracks now exist in half of the states in the United States. Public interest in the sport focuses primarily on major thoroughbred races such as the American Triple Crown and the Breeder's Cup races, which offer purses of up to $1,000,000.
Wagering on the outcome of horse races helps explain why horse racing has survived as a major professional sport. A major reason for the popularity of horse racing is the provision generally made for betting or wagering on the outcome of such races.
At racetracks, bettors may wager on a horse to win (finish first), place (finish first or second), or show (finish first, second, or third). Other popular wagers are the daily double (picking the winners of two consecutive races), exactas (picking the first and second horses in order), quinellas (picking the first and second horses in either order), and the pick six (picking the winners of six consecutive races). As horse racing and wagering on such races have become more popular, various refinements of the rules of betting (exactas, trifectas, odds, etc.) have evolved.
It is only logical that major gambling establishments, such as casinos, would have a connection to horse racing. In fact, many casinos are associated with racetracks. Thus, there is a great following in the casino industry of placing bets on horses.


The life of a downstream part disposed in a hot gas stream having a cooling medium injected into the stream through multiple orifices in a first upstream part is enhanced by changing the location, configuration or direction of flow of the cooling medium through the orifices. This change alters the temperature distribution of the flow field, affecting the second downstream part thereby enhancing its life. Properties of the cooling medium may also be changed, i.e., temperature and/or mass flow, to alter the temperature distribution of the flow field affecting the second downstream part to enhance its part life.

The present invention relates to a method for enhancing the life of a downstream part disposed in a gas stream into which a cooling medium is injected through orifices of a first part upstream of the second downstream part.
The life of parts exposed in a hot gas stream is very sensitive to the flow field temperature profile boundary conditions. For example, the life of turbine buckets mounted on a turbine wheel is a function of not only the average temperature to which the buckets are exposed but to the temperature distribution of the gas stream seen by the buckets. As will be appreciated, a hot gas stream of combustion products flows through nozzles and then the buckets of the various stages of a turbine. Typically, the hot gases of combustion ate cooled by a cooling medium ejected into the hot gas stream through multiple orifices in the nozzle vanes. The orifices may be located along the leading edges, as well as the suction and pressure sides of the nozzle stator vanes, and conventionally are interspersed between the hub and tip portions of the nozzle vanes.
Flowing cooling air through orifices such as in nozzle stator vanes is a conventional method used to control the metal temperature and life of the part containing the orifices. That is, designers of parts exposed to extreme conditions such as the high temperatures of the hot gas path in a gas turbine normally control local part life by providing orifices in that part and flowing a cooling medium through the orifices and about the part. The life of parts downstream from the part containing the cooling medium orifices is typically not considered in efforts to cool the upstream part.
In accordance with a preferred embodiment of the present invention, the life of a downstream part exposed in a hot gas stream is in part controlled by changing the location, configuration or direction of the flow of the cooling medium through the orifices, or by changing the properties of the cooling medium, such as mass flow and coolant temperature, to alter the temperature distribution of the flow field affecting the downstream part to enhance its part life. For example, the cooling medium ejected through orifices in an upstream part creates a flow field with a particular temperature distribution surrounding the downstream part. The downstream part life is affected by the resulting temperature field. Consequently, by locating, configuring or directing the flow of the cooling medium through the orifices, the temperature distribution of the flow field affecting the second part can be favorably altered to increase its part life. That is, the temperature distribution affecting the life of the downstream part is enhanced by appropriate design of the upstream injection characteristics of the cooling medium into the gas stream.
More particularly, in the case of a stage of a turbine where the nozzle vanes have orifices for flowing cooling medium into the hot gas stream, the location, configuration and/or direction of the orifices are changed to provide a desired temperature distribution of the flow field downstream in which the second part is situate to enhance the part life. For example, leading edge orifices of the nozzle vane can be directed generally radially outwardly whereby the temperature profile distribution of the gas flow seen by the downstream buckets is lower at the bucket tip than at the bucket hub. With orifices directed generally radially inwardly, the converse is true, i.e., the downstream temperature profile becomes hub strong. The effect is more pronounced because the primary stream flow has low momentum in the area of cool air injection. As a consequence, the downstream parts, e.g., buckets, are exposed to a temperature profile distribution amenable to enhanced part life. Many other useful applications will occur to those of skill in this art, including sizing end wall purges for leakages to manipulate the temperature seen by downstream parts.
As a further example of controlling the life of a downstream part exposed in a hot gas stream, the properties of the cooling medium such as mass flow and coolant temperature can be changed. Rather than change the location, configuration or direction of the flow through orifices, the flow through the orifices can be changed to alter the downstream part life. Temperature flow through the upstream orifices can be changed, for example, by supplying the cooling medium from a different stage of the compressor. The life of the downstream part may thus be enhanced, while maintaining adequate cooling of the upstream part. Mass flow through the upstream orifices likewise can be changed, with similar results.
In a preferred embodiment according to the present invention, there is provided in a method of enhancing the life of a second downstream part exposed in a gas stream having a cooling medium injected therein through multiple orifices in a first part upstream of the second downstream part, comprising the steps of (a) ascertaining a temperature distribution of a flow field of the gas stream affecting the part life of the second part and (b) changing the location, configuration or direction of flow of the cooling medium through the orifices to alter the ascertained temperature distribution of the flow field affecting the second part thereby to enhance the life of the second part.
In a further preferred embodiment according to the present invention, there is provided a method of enhancing the life of a second downstream part exposed in a gas stream having a cooling medium injected therein through multiple orifices in a first part upstream of the second downstream part, comprising the steps of (a). ascertaining a temperature distribution of a flow field of the gas stream affecting the part life of the second part and (b) changing a flow characteristic of the cooling medium including, by altering one of the temperature and mass flow of the cooling medium through the orifices to alter the ascertained temperature distribution of the flow field affecting the second part thereby to enhance the life of the second part.

Method for enhancing part life in a gas stream


A multi-user interactive web server and a communication method between users using the same are provided. The web server for providing predetermined information to users connected through a network includes a network connection manager for providing web information thereof to the connected users and a multi-user manager having a function of exchanging user information between users connected to the network connection manager. According to the present invention, it is possible to exchange information between the users connected to the same web server as well as to use the web information, using the multi-user interactive web server including a server having a function of providing the web information and a server having a function of performing communication between the connected users, and the communication method between users using the same.

1. Field of the Invention
The present invention relates to a multi-user interactive web server and a communication method between users. Specifically, this invention relates to: a multi-user interactive web server that provides information to a user, while also allowing communication between users; and a communication method between users.
2. Description of the Related Art
In general, users connect to a web server through a network using web browsers. Presently, a user can only download information provided by the connected web server. The web server does not provide a means of exchanging information between users connected to a web server.
FIG. 1 shows a conventional way of requesting and transferring information between a user and a web server. A user 100 is connected to a web server 120 through a network 110. The user connects using the user""s web browser and receives desired information from the web server 120.
The conventional web server 120 merely provides information contained in web pages or a related service to the user 100, as shown in FIG. 1. It is not possible for the user 100 to obtain information based on other user""s experience, such as the most useful information in the searched web page, from the other users connected to the same web server 120. Similarly, the user cannot provide such information to the other users because the conventional web server 120 does not provide a way of exchanging information between users connected to the web server.
To solve the above problem(s), it is an objective of the present invention to provide a multi-user interactive web server that allows users to exchange information between users as well as provide web-based information to a user.
It is another objective of the present invention to provide a communication method using such a web server.
Accordingly, to achieve the first objective, there is provided a multi-user interactive web server for providing information to users connected through a network, comprising a network connection manager for providing web information thereof to the connected users; and a multi-user manager for exchanging user information between users connected to the network connection manager.
The multi-user manager preferably comprises a user manager for storing user identification information transferred by the users; and a message processor for processing messages, wherein when a user sends a message having the user identification information of other users to whom said message is to be transferred, the message is transferred to said other users based on the user identification information stored in the user manager.
The network connection manager preferably provides a port number to a user so that the user is connected to the multi-user manager.
To achieve the second objective, there is provided a method for exchanging information between users connected to a web server, the method comprising providing web information and allowing a user to exchange user messages on receiving a request for connection; receiving and storing identification information from said user and other users; and checking for identification information of a subset of said other users and transferring user messages on receiving said user messages. The first step preferably comprises the steps of indicating port number of a predetermined web server, said web server being capable of managing user-to-user communication, the port number being used for transmitting messages between all the users connected to the web server; and transmitting the port number and opening a channel with the web server.
Preferably, when a user terminates connection with the web server, the web server erases user identification information thereof stored in the second step.
Preferably, if a user message contains user identification information of a subset of other users then the message is transferred only to the subset of users and if the user message does not contain any user identification information of other users the message is broadcast to all other users.
Preferably along with a transferred user message a program is provided to process the message. Further improvements include the program being in the Java programming language.

Multi-user interactive web server and communication method between users using the same


A multistage syringe includes a first barrel, a second barrel, a second barrel seal assembly, and a plunger assembly. The first barrel includes a first barrel channel and the second barrel includes a second barrel channel. The first barrel couples to the second barrel such that the first barrel channel aligns with the second barrel channel along a central axis. The plunger assembly includes a plunger coupled to a plunger handle. The plunger slidably couples with the first barrel channel along the central axis and the second barrel seal assembly slidably couples with the second barrel channel along the central axis. The plunger and the second barrel seal assembly cooperate to maintain a seal as the plunger transitions between a distal end of the multistage syringe and a proximal end of the multistage syringe.

Conventional syringes only allow for a single volume of fluid to be dispensed or aspirated for a linear travel distance of the plunger. If different volumes are required, multiple, independent syringes are needed. Accordingly, a need exists for alternative syringes which dispense or aspirate fluid in different stages of fluid volume for a linear travel distance of a plunger


The image sensing device provides a digital output for each pixel. As charge builds up in a pixel, the pixel output increases until it reaches a reference level. When the reference level is crossed the pixel is reset. This process is repeated several times in a given frame time cycle with the reference level steadily decreasing. The various reset times represent the light intensity on the pixel. For an image sensor array, the array is scanned multiple times during one image frame time cycle and the reference level is lowered each scan. This provides an image sensor that has built-in pixel non-uniformity suppression, digital output, and high sensitivity.

A typical image sensor senses light by converting impinging photons into electrons that are integrated (collected) in sensor pixels. After completion of integration cycle charge is converted into a voltage that is supplied to output terminals of the sensor. In CMOS image sensors the charge to voltage conversion is accomplished directly in the pixel itself and the analog pixel voltage is transferred to the output through various pixel addressing and scanning schemes. The pixels have incorporated in them a buffer amplifier, typically a source follower, which drives the sense lines that are connected to the pixels by suitable addressing transistors. The analog pixel signal can also be converted into a digital signal format on its way to the output. The digital signals are less susceptible to distortions, attenuation, and noise pickup and for this reason it is advantageous to make the conversion to digital format at the very beginning of the signal processing chain. Examples of sensors with signal conversion to digital format directly in the pixel itself can be found in U.S. Pat. No. 6,229,133 to Hynecek and in U.S. Pat. No. 5,461,425 to Fowler at al. However, this approach has also its own problems. The pixel with digital conversion incorporates many transistors and as a result has smaller aperture efficiency and sensitivity. Another problem is the A/D converter itself. The conversion typically relies on some reference voltage or a threshold to which the pixel output is compared. Since the pixel buffer amplifier has its own DC output offset level, that can vary from pixel to pixel, and the reference threshold of the A/D converter can also vary, the resulting digital output may be very non-uniform. This problem is tackled by using various analog readout schemes, such as the Correlated Double Sampling (CDS) that is applied before the A/D conversion. The CDS minimizes pixel non-uniformities by reading the pixel signal twice, once with charge and once without it. The difference is then free of the pixel DC level variations and the A/D conversion can take place. The CDS concept, however, does not eliminate non-uniformities in the column readout circuits even if the column readout is digital. The A/D converter threshold uniformity problems are minimized by using complicated self-calibrating and auto zeroing techniques as mentioned for example in the article: "A 1¼ inch 8.3 M Pixel Digital Output CMOS APS fro UDTV Applications" by: I. Takayanagi at al. published in: "Digest of Technical Papers 2003 IEEE International ISSCC Conference, pp. 216". Unfortunately such complicated systems can be used only in the array columns, since it would not be practical to integrate them into the pixels themselves. Such circuits also consume power and occupy a significant chip area thus contributing to increased cost of these sensors.
The sensor pixel non-uniformities, the column-to-column non-uniformities, and the A/D threshold variations thus represent persistent problem in CMOS image sensors that is not easily solved.

Image sensor with digital output and inherent pixel non-uniformity suppression


A semiconductor memory device has two complementary pairs of bit lines coupled to the same memory cells. According to a first aspect of the invention, the bit lines in one complementary pair cross over, so that each bit line in the first pair runs adjacent to one bit line in the second pair for one part of its length, and adjacent to the other bit line in the second pair for another part of its length. Coupling noise is thereby neutralized. Data-inverting circuitry is provided to compensate for the inversion of data that results from the cross-over of the bit lines. According to a second aspect of the invention, the two complementary pairs of bit lines are placed in separate interconnecting layers, to reduce coupling noise by reducing the capacitive coupling between the bit lines.

The present invention relates to a multi-port semiconductor memory device in which each memory cell is coupled to at least two complementary pairs of bit lines.
An example of this type of memory device is a multi-port static random-access memory (SRAM) in which each memory cell is coupled by transistors to a complementary pair of read bit lines, which supply data to an output port, and a complementary pair of write bit lines, which receive data from an input port. When data are written in a memory cell, the transistors coupling the memory cell to the write bit lines are switched on, and a write driver drives one of the write bit lines to the high level and the other write bit line to the low level. When data are read from a memory cell, the transistors coupling the corresponding memory cells to the read bit lines are switched on, thereby placing the two read bit lines at different electrical potentials, and the potential difference between the read bit lines is amplified by a sense amplifier.
The read and write bit lines are laid out so that each read bit line runs adjacent and parallel to one of the write bit lines for a considerable distance. Capacitive coupling between the adjacent bit lines creates a problem known as coupling noise. When the write driver alters the potential of a write bit line, the alteration is temporarily coupled onto the adjacent read bit line, possibly reversing the potential relationship between the two read bit lines. To avoid having this reversed potential relationship read out as incorrect data, operation of the sense amplifier must be delayed until sufficient time has elapsed for the correct potential relationship to be restored.
As memory integration densities rise, the spacing between the bit lines decreases and the problem of coupling noise becomes increasingly serious. In a typical multi-port SRAM with 0.35-.mu.m design rules, for example, the spacing between adjacent read and write bit lines is 0.5 .mu.m, and the capacitance between the bit lines is 0.1 pF, enough to require a significant delay of sense-amplification in order to ensure that correct data are read. The result is an undesirable data output delay.
The problem of coupling noise also appears in single-port dynamic random-access memory devices, in which the same bit lines are used for both read and write access. A known countermeasure to coupling noise in dynamic random-access memories is to have the two bit lines in each complementary pair cross over at one or more points. These cross-overs invert the data on the bit lines, but since the same bit lines are used for both reading and writing, the read and write data are inverted in the same way and no problem arises.
In a multi-port semiconductor memory, in which the same memory cells are accessed through different pairs of bit lines, the bit-line cross-over method of dealing with coupling noise cannot be employed without separate means of overcoming the problem of data inversion.

Multi-port semiconductor memory device with reduced coupling noise