A room-temperature-curable silicone elastomer composition that is highly workable prior to its cure and that cures to give a silicone elastomer having a desirable stiffness is made from a silanol-terminated polydiorganosiloxane, a dialkoxysiloxane of the formula ##STR1## where R.sup.1 represents monovalent hydrocarbon groups and R.sup.2 represents monovalent hydrocarbon groups having 1 to 8 carbon atoms, a tri- or tetra-alkoxysilane, and a curing catalyst.

1. Technical Field
The present invention relates to a composition that cures at room temperature to give silicone elastomer. More specifically, the present invention relates to a composition that cures at room temperature to give silicone elastomer whose postcure physical properties can be varied over a broad range.
2. Prior Art and Problems Therein
Compositions that cure at room temperature to give silicone elastomer are already known and have already entered into use in a wide range of industrial sectors. The mechanisms underlying their room-temperature cure include the hydrosilylation reaction, ultraviolet-based curing, and curing based on the condensation reaction between the silanol group and silicon-bonded functional groups. Among these, silicone elastomer compositions that cure by a condensation reaction mechanism offer the following features ready development of adhesiveness at room temperature, resistance to cure inhibition by contaminants that might be present in the curing environment, brief cure time obtained by simply mixing the base and catalyst, long-term storage stability as the single-package composition, and development of cure by simply standing in the atmosphere. As a result of these features, such silicone elastomer compositions have entered into broad use as adhesives, coatings, and sealants.
However, a problem associated with these particular compositions is that limitations are imposed on their post-cure mechanical properties as a result of the requirement that they exhibit pre-cure workability, i.e., in mixing, placement, and finishing by manual procedures. In specific terms, because the molecular weight of the polydiorganosiloxane main component must be held below a certain level in order to facilitate workability, it becomes essentially impossible to reduce the elastomer's postcure stiffness (as represented by such properties as the Durometer hardness and modulus) below a certain level.
The simplest method for solving this problem consists of the addition of unreactive polydiorganosiloxane. The problem with this method is that the unreactive polydiorganosiloxane additive bleeds onto the surface after curing and impairs the adhesiveness.
A fundamental strategy for solving this problem consists of the use of both polyfunctional crosslinker and difunctional chain extender. The polydiorganosiloxane then undergoes both crosslinking and chain extension during the crosslinking reaction and the post-cure crosslink density is thereby reduced.
The following two methods have been proposed within the sphere of this fundamental strategy:
(1) the addition of siloxane bearing two N,N-dialkylaminoxy groups in each molecule and siloxane bearing at least three N,N-dialkylaminoxy groups in each molecule, and PA0 (2) the addition of silane bearing two N-alkylacetamido groups in each molecule and either silane bearing at least three N-alkylacetamido groups in each molecule or siloxane bearing at least three N,N-dialkylaminoxy groups in each molecule.
Nevertheless, these methods still suffer from problems.
In the case of the first method, the use of the N,N-dialkylaminoxy group results in the generation of N,N-dialkylhydroxylamine by-product by the curing reaction. This creates the problem of an unpleasant hydroxylamine odor. In addition, as a result of the strong basicity of hydroxylamines, even a slight elevation in ambient temperature results in the critical problem of cure inhibition due to polydiorganosiloxane scission. Finally, this method is economically disadvantageous because N,N-dialkylaminoxy-containing siloxane is expensive.
In the case of the second method, the use of the N-alkylacetamido group again creates an odor problem due to the N-alkylacetamide produced as by-product during cure. Another drawback to the use of the N-alkylacetamido group is the occurrence of substitution reactions to give, e.g., the alkoxy group, when an active hydrogen-containing compound, e.g., alcohol, is present in the ambient. This also causes cure inhibition. Finally, this method is also rendered economically disadvantageous by the expense of N-alkylacetamido-containing silane.
It has otherwise been proposed that chain extension and crosslinking be conducted using functional groups that are already in wide application and that do not cause secondary reactions. This approach avoids the use of special, expensive functional groups as are used in the two methods discussed above. Japanese Patent Application Laid Open [Kokai or Unexamined] Number Sho 63-83167 [83,167/1988], assigned to Toray Silicone KK, proposes a method that uses, for example, RNHCH.sub.2 MeSi(OMe).sub.2, as chain extender. However, this method cannot be applied at a practical level because it is extremely difficult to economically synthesize this chain extender and because it is difficult to strike a stable balance with the crosslinker.

Modulus controllable room-temperature-curable silicone elastomer composition


Fully defined media that support pluripotent cell viability, proliferation, cloning, and derivation, as well as methods and compositions including these media are described. Methods for deriving iPS cells from adult individuals under defined, xeno-free conditions are also described.

Pluripotent cells, such as embryonic stem (ES) cells and induced pluripotent stem (iPS) cells, have the potential to differentiate into cells of all three primary germ layers (Thomson, et al., Science 282, 1145-1147 (1998)). The remarkable developmental potential of pluripotent cells has proven useful for basic research and clinical application. Many basic methods for human pluripotent cell culture, such as growth media, plate coating, and other conditions, have been developed and refined (Ludwig et al., Nat. Biotechnol 24, 185-187 (2006); Ludwig et al., Nat. Methods 3, 637-646 (2006)). For example, while human ES cells were initially cultured in fetal bovine serum (FBS)-containing media on murine embryonic fibroblast (MEF) feeder cells, fully defined media as well as defined protein matrices are now available (Ludwig et al., Nat. Biotechnol 24, 185-187 (2006)).
Over the past ten years, pluripotent cell culture methods have evolved considerably. Several growth media were developed that provide basic nutrients and growth factors for survival and expansion of pluripotent cells and directly determine how cells grow and differentiate. TeSR™ was one of the first defined media that supports pluripotent cell maintenance in an undifferentiated state in the absence of feeder cells or conditioned medium through multiple culture passages (Ludwig et al., Nat. Methods 3, 637-646 (2006); U.S. Pat. No. 7,449,334, each of which is incorporated herein by reference as if set forth in its entirety). TeSR™ contains 18 components in addition to the basal medium DMEM/F12 that itself has 52 components (Table 1).
The variety of different growth media available for pluripotent cell culture contributes to inconsistencies in research findings. The media that are presently used for pluripotent cell derivation and growth, including fully defined media, contain components that can influence pluripotent cells in various ways. Prior to the invention described herein, it was not known how each media component, alone or in combination with other components, affects various pluripotent cell functions such as viability, pluripotency, or differentiation in cell culture.
For example, albumin, the most abundant protein component present in most media, is a lipid carrier and, as such, can affect differentiation or maintenance of pluripotency via its associated lipids. The qualities of albumin and of its associated lipids determine whether it can be used for human pluripotent cell culture. However, albumin quality varies greatly depending on its source, even when produced from a recombinant genetic material, contributing to variations between experiments conducted under otherwise equivalent conditions. Also, while cloned human serum albumin is available, it is seldom used for routine experimentation due to its comparatively high cost.
Efforts to eliminate albumin from the medium have proved unsuccessful. Omission of albumin, or any other growth factor present in TeSR, led to a dramatic decline in human ESC culture performance, such as decreased cell viability, proliferation, and pluripotency (Ludwig et al., Nat. Biotechnol 24, 185-187 (2006)).
To fully exploit the potential of pluripotent cells for drug discovery, testing, and transplantation therapy, derivation and growth of these cells under fully-defined and, ideally, xeno-free, conditions is desirable. There is, thus an unmet need in the art for media free of components that introduce inconsistencies to maintain control over pluripotent cell culture conditions. Specifically, there is a need in the art for pluripotent cell culture media containing only those components that support pluripotent cell functions important for a specific culture objective.

This patent is subject to a terminal disclaimer.

Simplified basic media for human pluripotent cell culture


Various technologies described herein pertain to disambiguation of a mention of an ambiguous entity in a document. A set of candidate entities can be retrieved from an entity knowledge base based upon the mention of the ambiguous entity, where each of the candidate entities has a respective entity feature representation. Moreover, a document feature representation can be generated based upon features of the document and the respective entity feature representations of the candidate entities. A processor can be caused to select a subset of features from the document feature representation based upon a measure of how discriminative the features from the document feature representation are for disambiguating the mention of the ambiguous entity. A disambiguated result for the mention of the ambiguous entity can be determined based upon the subset of the features. The disambiguated result can be an unknown entity or one of the candidate entities.

With the large (and ever-growing) amount of information available on the World Wide Web, it can be desirable to assign deep structure and understanding to otherwise unstructured documents (e.g., textual documents) by determining content of the documents based on existing knowledge bases. For instance, given a document and an entity knowledge base, it can be desired to determine which entity in the entity knowledge base is mentioned in the document, or alternatively indicate that no entity from the entity knowledge base is mentioned in the document. However, in a web-scale entity knowledge base, it is highly likely that different entities may share a common name. Thus, different entities may have the same surface form (e.g., mention), which can lead to an inherent ambiguity when attempting to resolve a mention of an ambiguous entity to a matching entry in the entity knowledge base. By way of illustration, the entity knowledge base can include more than one "Joe Smith" (e.g., a doctor, a football player, etc.); following this illustration, a mention of "Joe Smith" in a document can be ambiguous since such mention may refer to "Joe Smith" the doctor, "Joe Smith" the football player, etc. from the entity knowledge base or an unknown "Joe Smith" outside of the entity knowledge base.
To resolve a mention of an entity in a document using an entity knowledge base, conventional approaches commonly extract features from the document and compare those features to feature representations of the entities in the entity knowledge base. Traditional approaches for entity disambiguation oftentimes employ a type of similarity measure that evaluates a distance between a context of a mention in a document and a context of an entity in an entity knowledge base. Examples of conventional similarity measures include cosine (with term frequency-inverse document frequency (TF-IDF)), Kullback-Leibler (KL) divergence (with a language model), and Jaccard. Other conventional approaches have explored the co-occurrence of multiple entities and perform joint recognition.
However, conventional entity disambiguation approaches can be problematic. For instance, various conventional approaches can build feature vectors out of the mention and the candidate entities, and perform similarity comparisons among feature vectors. Yet, some features can be missing, and features from different facets of the entity can be missing for different occurrences of the mention. Accordingly, a fixed weight for each dimension of the feature vector can be learned, while many of the features can be language components such as "the", "and", "a", "an", etc., which may not be discriminative for entity disambiguation. According to another example, for many conventional approaches, the features are designed and engineered for a particular entity knowledge base. Accordingly, such approaches can lack scalability and extensibility when applied to different domains where the entity knowledge bases therein have different schema.

Posterior probability pursuit for entity disambiguation


A machine for analyzing and displaying the concentration of a pressurized gas flowing through a delivery line in relationship to a reference gas. The machine includes a thermal conductivity detector which is connected to a microprocessor and a visual display. The microprocessor allows the machine operator to select any of a number of references and sample gas combinations for analysis.

Gas analyzers are useful machines for measuring the content of gas mixtures, particularly, the gas industry and in industrial uses of various gas mixtures. Previous gas analyzers include those which utilize infrared radiation, chemical cells, and thermal conductivity sensors. The content of a given gas can be computed by comparing its known properties against the readout displayed by the analyzer.
Prior art gas analyzers required frequent calibration and could not be readily adapted to measure varying mixtures of sample and reference gases. Particularly, analyzers which measured content based on thermal conductivity required that the user change the analyzer current, mix a number of known samples to determine the analyzer output at each mixture, calculate the analysis curve and enter the data, and finally to recalibrate the gas range with a known accurate gas sample. This procedure sometimes takes a full working day for an instrument technician to accomplish. Often, the prior machines were returned to the factory for recalibration at the customer's expense.


A hot fill container of the type that is used package fruit juices and other beverages includes a vacuum panel configuration that provides optimal volumetric efficiency, material usage and container strength and is particularly suited for use with smaller containers. The vacuum panel configuration includes a plurality of cageless vacuum panels that are separated by longitudinally extending outwardly projecting creases that are defined in a sidewall of the container. This arrangement maximizes the effective surface area of the vacuum panels relative to the external surface area of the container. Each of the longitudinally extending outwardly projecting creases has a curved outer surface that is convex when viewed in longitudinal cross-section. The cageless vacuum panels are constructed and arranged to be convexly curved when a pressure within the container is equal to an external pressure, but become concavely curved when a predetermined partial vacuum condition exists within said container.

1. Field of the Invention
This invention relates generally to the field of packaging, and more specifically to the field of hot fill type containers.
2. Description of the Related Technology
Hot fill containers are designed to be used with the conventional hot fill process, in which a liquid product such as fruit juice is introduced into the container while warm or hot, as appropriate, for sanitary packaging of the product.
After filling, such containers undergo significant volumetric shrinkage as a result of the cooling of the product within the sealed container. Hot fill type containers accordingly must be designed to have the capability of accommodating such shrinkage. Typically this has been done by incorporating one or more concave vacuum panels into the side wall of the container that are designed to flex inwardly as the volume of the product within the container decreases as a result of cooling.
Conventional vacuum panels are ordinarily framed or caged within the sidewall of the container by the presence of inwardly extending panel portions that are located near the periphery of the vacuum panel. Most of the volumetric contraction capability of the vacuum panel is accomplished by flexure of an interior portion of the vacuum panel that is framed or caged by the inwardly extending panel portions. Unfortunately, the contraction capability of vacuum panels in smaller containers has been limited to less than what is desired in many cases because the maximum surface area of the interior portions of the vacuum panels is limited by framing of the vacuum panel.
Hot fill containers must be designed to be strong enough in the areas outside of the vacuum panel regions so that the deformation that occurs as a result of the volumetric shrinkage of a product within the container is substantially limited to the portions of the container that are designed specifically to accommodate such shrinkage. In addition, since filled containers are often stacked on top of one another for transportation and distribution, the sidewall of such containers must be designed to have sufficient column strength in order to endure a predetermined minimum vertical load. It is important that such column strength not be degraded as the shape of the container changes as result of volumetric shrinkage within the container. To that end, conventional designs for hot fill containers typically included a plurality of vertically extending non-recessed sidewall portions serving as posts between the vacuum panel areas in order to impart additional column strength.
Most hot fill type containers are fabricated from polyethylene terephthalate, which is otherwise known as PET. PET possesses excellent characteristics for such containers, but PET resin is relatively expensive. Accordingly, a PET container design that reduces the amount of material that is used without sacrificing performance will provide a significant competitive advantage within the packaging industry. The presence of numerous surface features such as deeply recessed vacuum panels requiring extensive framing on conventional container designs has inhibited lightweighting of the container to some extent.
A need has existed for an improved hot fill container design provides optimal volumetric efficiency, material usage and container strength and that is particularly suited for use with smaller containers.

Hot fill container having improved vacuum panel configuration


The present invention addresses the problem of providing a small-sized, low-cost medical optical imaging device capable of irradiating even a deep portion of a dental root canal. Provided is a medical optical imaging device (4) that is provided with an illumination unit (6) for emitting illumination light to a subject, an imaging section (7) for imaging the subject, and a controller (8) for controlling at least the imaging section (7). The imaging section (7) is provided with an imaging lens system (71) and an imaging element (72) for receiving an optical image created by the imaging lens system (71). When viewed from the subject side, the illumination unit (6) is disposed in front of the imaging lens system (71) and overlapping the imaging lens system (71).

Therapeutic procedures including surgeries or dental examinations using a dental examination system generally employ a microscope, an imaging device, and an illumination device for precise treatments and diagnoses.
Examples known as a dental examination system including an imaging device and an illumination device are an oral cavity observation apparatus for treatment and a dental treatment device described in Patent Literature 1 and a dental optical imaging device described in Patent Literature 2.
The oral cavity observation apparatus for treatment according to Patent Literature 1 employs coaxial illumination using the same axis to irradiate an observation site in an oral cavity with light emitted from a light source (11) and to capture images thereof, and a half mirror (10) is used for irradiation of the observation site.
In the dental optical imaging device according to Patent Literature 2, LED illumination devices (35, 36), as a target for above-described comparison, are arranged around the lens diagonally to an optical axis AX of an extraoral camera.


Various systems and methods for error reduction in a digital information system are disclosed herein. As one example, a digital storage system is provided that includes a soft output Viterbi algorithm channel detector operable to receive an encoded data set, and to provide a hard and a soft output representing the encoded data set. The hard and the soft output from the soft output Viterbi algorithm channel detector are provided to a single parity row decoder that provides another hard output that is an error reduced representation of the encoded data set. The encoded data set is additionally provided from the buffer to another channel detector via a delay element. The hard output from the single parity row decoder and the time shifted encoded data set are provided to coincident with each other to another channel detector.

The present invention is related to systems and methods for detecting and decoding digital information. More particularly, the present invention relates to systems and methods for detecting and correcting errors associated with an information transfer.
Digital communication systems (e.g., sets of wireless communication devices) and digital storage systems-(e.g., hard disk drives) provide for transfer of different types of information. For example, in the case of communication systems, digital information is transferred substantially in real time from one communication device to another. In contrast, digital information transfer involving digital storage systems typically involves a non-real time transfer of digital information that was previously stored to a storage device. While there are fundamental differences between the aforementioned information transfer approaches, the general goal of both approaches is to transfer information as accurately as possible in the presence of impairments such as noise and inter-symbol interference (ISI).
The goal of increasing the accuracy of information transfer has fueled development of progressively more complex information transfer approaches that include increasingly elaborate error correcting schemes (ECSs). As an example, a state of the art information transfer approach may include a substantial number of parity bits built into the information being transferred. These parity bits introduce redundancy into the signal prior to transmission, and are subsequently used to decode the encoded information. FIG. 1 depicts an exemplary state of the art transfer system tailored for a digital storage system. It should be noted that a typical state of the art system tailored for a digital communication system would typically include the same level of complexity or possibly greater.
Turning to FIG. 1, a block diagram is provided for a known digital storage system 1 that utilizes an elaborate row and column parity approach for error detection and correction. Digital storage system 1 includes an encoder 2 that encodes information bits by interleaving parity bits throughout the original information. Encoder 2 is typically a two-dimensional product code (TPC) encoder. After the original information is encoded, it is provided to recording channel 3 that typically includes various physical and electrical components, such as a read/write head, a read/write head armature, a recording media, a pre-amplifier, or other related circuitry or components.
The encoded information is passed from recording channel 3 to a soft output Viterbi algorithm (SOVA) channel detector 4. SOVA channel detector 4 processes the received encoded information using a bit detection algorithm. The output of SOVA channel 4 includes a combination of hard decisions and reliability estimates (i.e., respective estimates as to the reliability of the respective hard decisions). Both the soft and hard outputs of SOVA channel detector 4 are provided to a decoder 5 that is responsible for de-interleaving the parity bits and decoding the recovered information bits using the parity bits.
Operation of digital storage system 1 is exemplified where original information (e.g., uk=010110) is to be stored in recording channel 3. This original information is represented by Table 1 below.
TABLE 1Original Information (uk)011100The original information, uk, is provided to encoder 2 that encodes the information. Where it is assumed that encoder 2 is a two-dimensional product (TPC) encoder, a parity bit is added to each row and to each column of table 1 to produce an even parity code (i.e., each column and each row contains an even number of 1's). Thus, the original information represented by a 3×2 table is formed into encoded information, ck, that is formed in a 4×3 table. The parity laden 4×3 table is represented as table 2 below.
TABLE 2Original Information Interleaved with Parity (ck)011110000101
For simplicity, the example assumes that each column of table 2 corresponds to a single parity codeword. However, in a typical implementation, this would not be the case as the parity bits would be pseudo-randomly interleaved throughout the original information bits, rather than being placed at the end of each column and row. Thus, a typical implementation would be much more complex.
In this example, the resulting codeword, ck=010111001001, is recorded by recording channel 3. When retrieved from recording channel 3, a signal xk provided from recording channel 3 may be corrupted by noise, nk, resulting in a corrupted signal yk. The noise, nk, may be, for example, additive Gaussian noise. SOVA channel detector 4 receives the corrupted signal, yk, and produces hard decisions and corresponding soft reliability estimates. Decoder 5 receives the output of SOVA channel detector 4 and decodes the output to recover the original information using the interleaved parity information.
In some embodiments, the parity bits may be used in an iterative decoder and detection approach to increase accuracy of the recovered information. An exemplary system 60 using such an iterative decoder and detection approach to increase the accuracy of the recovered information is shown in FIG. 2. A first SOVA channel detector 61 processes information from the read channel, and provides a combination of hard and soft outputs representing the original information and interleaved parity bits. This combination of hard and soft outputs are provided to a first stage decoder 62. First stage decoder 62 includes a row detector 63 and a column detector 64, and a row decoder 66 and a column decoder 67. In addition, first stage decoder 62 includes a delay element 65, and a collection of summers 68, 69 and 71.
The encoded bits are stored in the read channel (not shown) in a table comprising rows and columns such as Table 2 above. Row decoder 63 receives the hard and soft detector outputs from SOVA channel detector 61, and uses the hard and soft detector outputs to decode the rows. Similarly, column decoder 64 receives the hard and soft detector outputs from SOVA channel detector 61, and uses the hard and soft detector outputs to decode the columns. Row decoder 63 and column decoder 64 generate outputs that are combined by summers 68 and 69 with the outputs of SOVA channel detector 61 delayed by delay element 65. The combination of the outputs of SOVA channel detector 61 and column decoder 64 are provided to another row decoder 66. Likewise, the combination of the outputs of SOVA channel detector 61 and row decoder 63 are provided to another column decoder 67. The data provided to row decoder 66 and column decoder 67 is used to decode the respective rows and columns. In particular, row decoder 66 uses information generated by column decoder 64 to further decode the rows, and column decoder 67 uses information generated by row decoder 63 to further decode the rows. This type of iteration in the decoder requires both column and row decoders because each uses information from the other to make decoding decisions.
In addition, there is an iteration between the detector and decoder processes. As shown in FIG. 2, the outputs of the row decoder 66 and column decoder 67 are combined by summer 71 and provided to another SOVA channel detector 72 and to a delay element 73. SOVA channel detector 72 also receives the same input that was provided to SOVA channel detector 61 after passing through delay element 75. SOVA channel detector 72 generates soft and hard outputs that are combined by a summer 74 with the combined outputs of the row decoder 66 and column decoder 67 as delayed by delay element 73. This information is then provided to another channel decoder 76.
Channel decoder 76 provides the same processing implemented by channel decoder 62, thus providing the iterative approach to decoding. Channel decoder 76 includes components 83-91 that correspond to similar components 63-71, respectively. In addition, channel decoder 76 includes a delay element 92 that provides a time delay that is equal to the time delay provided by a delay element 85. The outputs of row decoder 86 and column decoder 87 of channel decoder 76 are combined by a summer 91 with the delayed input to channel decoder 76. The result is the recovered original information bits after a double pass iteration that typically provides for greater error protection.
As will be appreciated from the preceding discussion, while system 60 intuitively provides a reduction in errors, system 60 requires a substantial amount of circuitry. In particular, implementing system 60 involves duplicating detection and decoding logic, and memory. Consequently, system 60 consumes a relatively large amount of area on a semiconductor die, and is also relatively inefficient in terms of power consumption. In addition, all of the iterative processing takes a relatively large amount of time to be performed, which decreases the overall speed of the system. Further, the approach of system 60 may not provide sufficient error reduction even where the increased costs of space and power are sustainable.
Hence, for at least the aforementioned reasons, there exists a need in the art for advanced systems and methods for error reduction.

Systems and methods for error reduction associated with information transfer


A data transmission circuit includes a control signal generation circuit, a write state machine, a conversion circuit, a read state machine, and a selection circuit. The control signal generation circuit receives a strobe signal and a clock signal in response to an enable signal, generates a write control signal that is activated in response to a rising edge of the strobe signal, and generates a read control signal that is activated in response to a first rising or falling edge of the clock signal after the write control signal is activated. The write state machine is activated in response to the write control signal, changes its internal state in synchronization with the strobe signal, and sequentially outputs input control signals in response to the changed internal state. The conversion circuit converts serial data to parallel data in response to the input control signal sequentially output from the write state machine and latches the parallel data. The read state machine is activated in response to the read control signal, changes its internal state in synchronization with the clock signal, and sequentially outputs output control signals in response to the changed internal state. The selection circuit outputs the parallel data latched in the conversion circuit in the same order that the serial data is sequentially input to the conversion circuit in response to the output control signals sequentially output from the read state machine.

1. Field of the Invention
The present invention relates to a data transmission circuit of a semiconductor device, and more particularly, the present invention relates to a control signal generation circuit which generates control signals used for data write and/or read operations, a data transmission circuit containing the control signal generation circuit, and a method of transmitting data.
A claim of priority under 35 U.S.C. §119 is made to Korean Patent Application No. 2003-639, filed 6 Jan. 2003, the contents of which are hereby incorporated by reference in its entirety as if fully set forth therein.
2. Description of the Related Art
When a semiconductor system receives input data from an external source, it is typically supplied with a strobe signal indicative of a start of the data and a sampling time. If a time gap exists between the strobe signal and a clock signal with which the semiconductor system operates, a receiving circuit is needed to compensate for the time gap so as to securely receive the externally supplied input data. This time gap can occur between semiconductor systems which operate with the same clock signal and semiconductor systems which operate with different clock signals.
Also, even though they are synchronized with the same clock signal, a time gap also occurs between the strobe signal and the data as a result of delays in data paths, packages or sockets. Thus, a compensation circuit is needed to prevent the time gap from causing the semiconductor system to operate abnormally. The compensation circuit samples externally supplied input data in synchronization with the strobe signal and increases a bit time of the sampled data using a parallel latch or a flip-flop. Thereafter, the compensation circuit samples the sampled data again using an internal clock signal and outputs re-sampled data. Here, the bit time amounts to half of one period of the internal clock signal.
While the compensation circuit can maintain the sample time and hold time by increasing the bit time of the sampled data, a latency is introduced when data is sampled. That is, the compensation circuit creates an undesired latency between data input and output, which in turn increases a data access time of the semiconductor system.

Control signal generation circuit and data transmission circuit having the same


A method and system for fault indication on a substrate. A method of the present invention includes the following steps. It is determined whether data includes at least one suspicious bit. A pattern generator is controlled with the data. A beam of radiation is patterned using the pattern generator. Features are projected by the patterned beam of radiation onto a target portion of a substrate. One or more markers are projected by the patterned beam of radiation onto the substrate indicating the target portions that correspond with the at least one suspicious bit.

1. Field of the Invention
The present invention is directed to a light patterning device and a method of using the same.
2. Background Art
A patterning device is used to pattern incoming light. A static patterning device can include reticles or masks. A dynamic patterning device can include an array of individually controllable elements that generate a pattern through receipt of analog or digital signals. The analog or digital signals are transmitted through a data path. The algorithm used to control the dynamic patterning device, so that its individually controllable elements are in a proper state to form a desired pattern, is called a rasterization algorithm or optical rasterization algorithm. Example environments for use of the patterning device can be, but are not limited to, a lithographic apparatus, a projector, a projection display apparatus, or the like.
Large amounts of data are manipulated by and transported through the data path to control the array of individually controllable elements of a dynamic patterning device, which makes it probable that bit errors will result somewhere in the data path. These bit errors could lead to errors in the patterns exposed by the patterned light.
Therefore, what is needed is a method and system for detecting if a bit error exists in the data path. If a bit error is detected, it should be determined whether the bit error has led to an error in an exposed pattern.

System and method for fault indication on a substrate in maskless applications


The present invention relates to the identification of a genomic integration site for heterologous polynucleotides in Chinese Hamster Ovary (CHO) cells resulting in high RNA and/or protein production. More specifically it relates to CHO cells comprising at least one heterologous polynucleotide stably integrated into the S100A gene cluster of the CHO genome and to methods for the production of said CHO cells. Further, the invention relates to a method for the production of a protein of interest using said CHO cell and to the use of said CHO cell for producing a protein of interest at high yield. Integration within these specific target regions leads to reliable, stable and high yielding production of an RNA and/or protein of interest, encoded by the heterologous polynucleotide.

Chinese hamster ovary (CHO) cells are the most popular host cells for the recombinant production of therapeutic proteins. Classical cell line development procedures rely on the random integration (RI) of expression vectors followed by selection and screening of subclones for optimal productivity behavior. Random integration is associated with a large heterogeneity in the resulting cell population, owing to unpredictable chromosomal positioning effects, variable copy numbers and stability issues. High producer cells account for only a small proportion of the randomly transfected cells and tend to be outgrown by low producer cells. Hence, a large number of clones need to be screened in order to identify and isolate one individual clone suitable for sustained biopharmaceutical protein production and fermentation process development.
Positional effects on the expression of heterologous genes can result from, e.g., chromatin structure, genomic imprinting or the presence of transcriptional regulator elements, such as genomic enhancer elements, silencer elements or promoter elements in the vicinity of the integration site (C. Wilson et al. Annu. Rev. Cell Biol. 1990, 6, 679-714). Many of these elements within the genome are not known or characterized, and the potential of a genomic locus in a cell line development process therefore hard to predict.
By replacing classical random integration with targeted integration (TI) of the protein expression vector into one or more pre-determined genomic locus/loci, these disadvantages can be overcome. Targeted integration makes the cell line development process much more predictable as all subclones will have identical genomic set ups negating the need for extensive screening procedures.
The challenge for a cell line development process that relies on targeted integration lies in the identification of a suitable genomic locus, often called a "hot spot". The ideal site(s) will support sufficient levels of protein expression from single or low copy numbers, exhibit long term stable expression levels without excessive down-regulation, be amplifiable using metabolic selection markers such as DHFR or GS in conjunction with MTX or MSX, and will be located so that integration of transgenes does not negatively impact cell growth or protein product profiles.
The S100A6 gene is part of the S100A gene cluster encoding a group of known calcium-binding proteins, e.g. S100A1, S100A13, S100A14, S100A16, S100A3, S100A2, S100A4, S100A5 and S100A6. The cluster comprises a "side cluster" including the S100A1, S100A13, S100A14 and S100A16 genes and a "main cluster", which includes the S100A3, S100A4, S100A5 and S100A6 genes.
In the present invention, it is shown that the stable integration of heterologous polynucleotides within the S100A gene cluster of the CHO cell genome increases the production of a heterologous gene product. Specifically, stable integration within the upstream and downstream regions flanking the S100A3/A4/A5/A6 main gene cluster, enables a predictable, high level and stable production of a heterologous gene product, including recombinant proteins, such as antibodies and fusion proteins, or regulatory RNAs, such as shRNAs or miRNAs.


A tensioning assembly 10 for a cable bolt 11 comprises a clamping device (14, 16) adapted for fastening to the bolt and an outer member 18 adapted for interacting with the clamping device. The outer member 18 is able to undergo relative movement to the clamping device in the direction of the bolt's axis, and under such movement, the clamping device is caused to fasten to the bolt. Furthermore, the outer member is adapted for interacting with the bolt 11 whereby, during such relative movement, twisting of the bolt 11 with respect to the outer member 18 is restrained.

Roof and wall support is vital in mining and tunnelling operations. Mine and tunnel walls and roofs consist of rock strata, which must be reinforced to reduce the possibility of collapse. Rock bolts, such as rigid shaft rock bolts and flexible cable bolts, are widely used for consolidating the rock strata.
In strata support systems, a bore is drilled into the rock by a drill rod, which is removed and a rock bolt is then installed in the drilled hole and secured in place, either mechanically or by using a resin or cement based grout. The rock bolt is tensioned which allows consolidation of the adjacent strata by placing that strata in compression.
To allow the rock bolt to be tensioned, an inserted end of the bolt may be anchored mechanically to the rock formation by engagement of an expansion assembly on the end of bolt with the rock formation. Alternatively, the bolt maybe adhesively bonded to the rock formation with a resin bonding material inserted into the bore hole. Alternatively, a combination of mechanical anchoring and resin bonding can be employed by using both an expansion assembly and resin bonding material.
When resin bonding material is used, it penetrates the surrounding rock formation to adhesively unite the rock strata and to hold firmly the rock bolt within the bore hole. Resin is typically inserted into the bore hole in the form of a two component plastic cartridge having one component containing a curable resin composition and another component containing a curing agent (catalyst). The two component resin cartridge is inserted into the blind end of the bore hole and the mine rock bolt is then inserted into the bore hole such that the end of the mine rock bolt ruptures the two component resin cartridge. With rotation of the mine rock bolt about its longitudinal axis, the compartments within the resin cartridge are shredded and the components are mixed. The resin mixture fills the annular area between the bore hole wall and the shaft of the mine rock bolt. The mixed resin cures and binds the mine rock bolt to the surrounding rock.
Tension assemblies have been proposed to provide tension along cable bolts, for example, which in turn provides a compressive force on the substrate surrounding the anchored bolt, usually a mine shaft roof substrate. Such tension assemblies often involve hydraulic means for installation and require the installer to lift the means above chest height to be placed on the cable end exposed from the bore hole. This can lead to safety issues, depending on the mine shaft roof height.
In one such assembly, with the resin cured about the cable portion in the bore hole, a nut is placed onto a thread cut into a portion of the outer wires of the cable bolt remaining outside the bore hole. The nut is then rotated on the cable bolt toward and to abut the substrate about the bore hole either directly or through a bearer plate disposed on the shaft between the substrate and the nut. Rotation of the nut is continued for a predetermined number of turns to provide tension along the cable. This method has been found to be unreliable in practice, with failures occurring between the nut and cable.
In another assembly, a threaded rod is coupled onto a distal end of the cable using an external coupling. The coupling is disposed within the bore and the threaded rod is arranged to project from the bore. A plate is then disposed on the rod and a nut threadably engaged with the rod to capture the plate. The nut is rotated on the rod such that the plate is forced onto the substrate about the bore hole. This assembly requires a portion of the bore hole, adjacent the bore hole opening, to be widened to accommodate the external coupling. This is disadvantageous in that it requires two drilling events when forming the bore hole. Alternatively, if the bore hole is drilled to have one diameter large enough to accommodate the fitting, a larger space is created between the bore hole wall and the cable bolt, requiring more resin to fix the cable bolt in the bore. This has been shown to reduce bond strength between the cable, resin and bore hole wall.
In a further assembly, a clamping device is mounted onto a distal end of the cable bolt outside the bore. An outer barrel is then located over to engage with the clamping device, whereby the barrel can be moved axially with respect to the cable bolt along the clamping device. This movement can cause a plate that is disposed on the rod to be forced by the outer barrel onto the substrate about the bore hole.
Such known assemblies do not, however, prevent the cable bolt from twisting during tensioning. After a time, the cable bolt can twist back whereby bolt tension is progressively lost.
A reference herein to prior art is not an admission that the prior art forms part of the common general knowledge of a person of ordinary skill in the art in Australia or elsewhere.


From a synthesis gas mainly consisting of hydrogen and carbon oxides an acetic acid product consisting of acetic acid, acetic anhydride and/or methyl acetate is prepared by reactions known per se in a technically simple reaction sequence and a high conversion degree when the reactions are combined such that in a first step at a pressure of 5-200 bar and a temperature of 150.degree.-400.degree. C. the synthesis gas is converted in the gas phase in a first reactor to methanol, of which at least a substantial proportion is converted to dimethyl ether in the same reactor in the presence of one or more catalysts which together catalyze the reactions EQU CO+2H.sub.2 .revreaction.CH.sub.3 OH (1) EQU 2 CH.sub.3 OH.revreaction.CH.sub.3 OCH.sub.3 +H.sub.2 O (2). and EQU CO+H.sub.2 O.revreaction.CO.sub.2 +H.sub.2 (3). and then passing the entire effluent from the first reactor to a second reactor in which methanol and dimethyl ether at a pressure of 1-800 bar and a temperature of 100.degree.-500.degree. C. are carbonylated to the desired product in the presence of one or more catalysts which together catalyze the reactions EQU CH.sub.3 OH+CO.fwdarw.CH.sub.3 COOH (4) EQU CH.sub.3 OCH.sub.3 +CO.fwdarw.CH.sub.3 COOCH.sub.3, (5). and optionally EQU CH.sub.3 OCH.sub.3 +2CO.fwdarw.(CH.sub.3 CO).sub.2 O (6). and EQU CH.sub.3 COOCH.sub.3 +CO.fwdarw.(CH.sub.3 CO).sub.2 O (7). and possibly even the hydrolysis EQU CH.sub.3 COOCH.sub.3 +H.sub.2 O.revreaction.CH.sub.3 COOH+CH.sub.3 OH(8).

It is well-known to convert a synthesis gas mixture as mentioned catalytically into methanol according to the reaction EQU CO+2 H.sub.2 .revreaction.CH.sub.3 OH (1)
Examples of suitable methanol synthesis catalysts are oxides of zinc and chromium; oxides of zinc, copper and chromium; and oxides of zinc, copper and aluminum; as well as zinc-copper-chromium-lanthanum oxides. Under typical conditions of reaction these catalysts will also catalyze the water gas reaction (shift reaction) EQU CO+H.sub.2 O.revreaction.CO.sub.2 +H.sub.2 (3)
In conventional methanol synthesis, which typically takes place at 220.degree.-400.degree. C. and 10-500 kg/cm.sup.2, the degree of conversion per passage is usually low because of an unfavorable equilibrium of methanol formation in reaction (1),and for this reason high ratios of recycling are needed, usually from 4:1 to 10:1. In order to improve the equilibrium it has been proposed (in connection with the conversion of synthesis gas into petrol (gasoline)) in U.S. Pat. specification No. 3,894,102 to combine the methanol synthesis with the catalytical conversion of a substantial proportion of the methanol formed into dimethyl ether according to the methanol dehydration reaction EQU 2 CH.sub.3 OH.revreaction.CH.sub.3 OCH.sub.3 +H.sub.2 O (2)
Many materials are known to catalyze this reaction, notably the so called acidic dehydration catalysts as for instance .gamma.-alumina (which is employed according to the above patent specification), silica, silica-alumina and crystalline aluminosilicates such as zeolites.
Reactions (1) to (3) are normally carried out heterogenically in gas phase over a solid, optionally supported catalyst.
It is well-known to carbonylate alkanols and ethers catalytically into carboxylic acids containing one carbon atom more than the starting material, and esters or anhydrides thereof, specifically to carbonylate methanol and dimethyl ether to form acetic acid, its anhydride or methyl acetate according to the reactions EQU CH.sub.3 OH+CO.fwdarw.CH.sub.3 COOH (4) EQU CH.sub.3 OCH.sub.3 +2CO+H.sub.2 O.fwdarw.2CH.sub.3 COOH (4a) EQU CH.sub.3 OCH.sub.3 +CO.fwdarw.CH.sub.3 COOCH.sub.3 (5) EQU CH.sub.3 OCH.sub.3 +2CO.fwdarw.(CH.sub.3 CO).sub.2 O (6)
and EQU CH.sub.3 COOCH.sub.3 +CO.fwdarw.(CH.sub.3 CO).sub.2 O (7)
These reactions have been carried out in liquid phase and in gas phase over a solid catalyst bed, and various catalysts have been proposed, especially noble metal catalysts. A few publications on these reactions are mentioned in the following.
In U.S. Pat. specification No. 3,689,533 there is mentioned a number of drawbacks in older carbonylation reactions (4) and (5), notably a low degree of conversion and many by-products, in part difficult to remove. To overcome these drawbacks this patent proposes to react methanol and dimethyl ether with carbon monoxide in gas phase at a temperature of 50.degree.-500.degree. C. and a CO partial pressure of 0.07 to 1050 kg/cm.sup.2 abs., preferably 0.7-50 kg/cm.sup.2 abs., in the presence of a supported rhodium catalyst promoted with iodine, bromine or compounds thereof. It appears from the specification that CO is added in a pure form but in certain cases steam may be present.
The slightly elder British patent specification No. 1,233,121 enumerates the same drawbacks in known carbonylation reaction as the above US patent specification and proposes a similar reaction as that, but conducted in liquid phase (homogenous catalysis), viz. the carbonylation of an alkyl compound containing n carbon atoms (n being an integer 6-20) in the form of an alcohol, a halide, an ester or an ether by the reaction at a temperature of at least 50.degree. C. with carbon monoxide in the presence of a catalyst of rhodium or a rhodium compound and a promoter selected amongst bromine, iodine and compounds thereof. In Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, vol. A1, page 47, VCH Verlagsgesellschaft, Weinheim, it is stated that this process, which is known as the Monsanto process when the alkyl compound is methanol and which has gained industrial spreading, leads to the carbonylation of methanol into acetic acid in a yield of 99%, calculated from methanol, and 90%, calculated from CO. Important by-products are stated to be hydrogen and carbon dioxide formed via the water gas shift reaction (3), which is known to be catalyzed by rhodium under homogenous process conditions (Ullmann, l.c. p. 49 and J. Am. Chem. Soc. 99, 2791, 1977), accompanied by a significant loss of valuable CO. In this process methanol is also added in pure form. The methanol process suffers, as mentioned, from unfavorable equilibria, which apart from a high reaction pressure call for cooling of the entire process stream, condensation of methanol and recycling of remaining large amounts of unconverted synthesis gas.
It is moreover known from U.S. Pat. specification No. 4,356,320 to conduct the carbonylation by the aid of a base metal catalyst, viz. a nickel catalyst in the presence of an organophosphorus(III) compound and using an iodide. Even in this case CO and methanol are added in pure form.
It is characteristic for the carbonylation processes mentioned that the carbonylation reaction is of the order zero with respect to carbon monoxide as well as methanol and dimethyl ether (Ullmann, l.c. page 48). As moreover the reactions (4)-(7) have equilibrium almost completely in favor of the products, one is free to choose space velocity, pressure and temperature in a way so as to obtain close to complete conversion of the reactants in one single passage through the reactor.
From German patent specification No. 26 10 036 there is known a process for preparing symmetric or unsymmetric carboxylic anhydrides of the formula (RCO).sub.2 O, wherein R denotes C.sub.1-4 alkyl and hence specifically acetic anhydride, from the corresponding alkyl alkanoates or alkyl ethers, i.e. specifically according to reactions (6) and (7), under substantially anhydrous conditions in the presence of noble metal catalysts of group VIII of the Periodical Table of Elements, and a complex promoter containing at least an organonitrogen or organophosphorus compound where N and P are trivalent, together with a metal belonging to groups IVa, Va or VIa of the Periodical Table of Elements; the reaction takes place at a CO partial pressure of 0.07-678 bar and a temperature of 25.degree.-350.degree. C. The specification mentions that carbonylation at low pressures earlier had only resulted in acetic acid, whereas carbonylation in acetic anhydride only could be carried out a very elevated pressures, a disadvantage which is told to have been remedied by using the abovementioned catalyst system. The reaction is normally carried out at moderately elevated pressure, e.g. 1-69 and preferably 2-14 bar, and the reaction time is in the range of 0.1-20 hours dependent of the temperature and pressure. It is advantageously conducted in liquid phase (homogeneously) with a solvent or diluent present. As noble metal catalyst there is preferably employed a rhodium compound.
German published patent specification No. 34 40 646 describes the preparation of monocarboxylic anhydrides (RCO).sub.2 O by the reaction of the corresponding alkyl alkanoates or alkyl ethers in gas phase by gas phase catalysis with a supported catalyst with an organosilicon compound having alkoxy or halogen groups as well as organo-nitrogen, organophosphorus, organoarsenic, organosulphur, mercapto or thioether groups as a polyfunctional attachment agent between the support at one hand and a noble metal compound of group VIII in the Periodical Table of Elements at the other hand. The specification says that there is obtained an improved catalyst activity and selectivity compared to the use of supports impregnated with catalyst solutions.
The fundamental reactions in the conversion according to the invention thus are well-known per se but it has not been suggested to combine them in one reaction sequence as here proposed. However, it has now been surprisingly found that there is obtained a technically simple reaction sequence by such a combination, and a very high degree of conversion already after one passage based on the synthesis gas, by such a combination. Under certain circumstances there is obtained practically full conversion of synthesis gas to acetic acid by one passage only.
As explained, in the known processes for carbonylation of methanol and dimethyl ether to acetic acid and methyl acetate or the anhydride, the needful carbon monoxide has been added as such. In practice carbon monoxide is normally obtained by various reactions which involve the reforming of methane or higher hydrocarbons. In the synthesis gas thereby formed, CO is present along with H.sub.2 and CO.sub.2 which accordingly must be separated, e.g. by an expensive cryogenic separation, in order to provide the feed gas needed. It is a particular advantage in the present process that one avoids this separation, avoids a separate preparation of methanol or dimethyl ether (or mixtures thereof), and in a coherent reaction sequence by a suitable control of the reactions and recycling streams can obtain a high conversion in just one passage of a synthesis gas as stated into acetic acid, methyl acetate, acetic anhydride or mixtures thereof.

Process for preparing acetic acid, methyl acetate, acetic anhydride or mixtures thereof


An interface circuit for a capacitive sensor capable of outputting a detection signal with high stability and reliability while suppressing to a minimum the influence of offset and temperature dependency onto the output signal. In a differential capacitance type sensor having a common electrode connected to the ground potential, an electric discharge redistributing method and impedance conversion technique are adopted for obtaining an output voltage which is in proportion to the inter-electrode relative displacement. A switching mechanism is provided for mitigating an offset voltage component contained in the output due to an input offset voltage of the operational amplifier. Further, the sensitivity of the capacitive sensor is increased with the temperature-dependent drift of the sensor output being suppressed by providing additionally a power source change-over switches for allowing the voltages sampled in response to predetermined clocks to be differentially amplified.

1. Field of the Invention
The present invention generally relates to a capacitance detecting circuit for detecting capacitance of a capacitive sensor which is employed for measuring pressure, acceleration, angular velocity or the like. More particularly, the invention is directed to an interface circuit connected to a capacitive sensor including first and second capacitors at least one of which has variable capacitance, wherein a common terminal of the first and second capacitors is connected to ground potential or a constant potential level.
2. Description of Related Art
A capacitive sensor for detecting a pressure of a fluid or acceleration and/or angular velocity of a moving object, can be manufactured by semiconductor micromachining techniques and can output an electric signal representing the fluid pressure, the acceleration, the angular velocity, etc. by detecting change or variation in the capacitance. The capacitive sensor as well as the capacitance detecting circuit therefor can provide advantages in that they can be manufactured in a miniaturized structure on a mass-production scale with high accuracy and enhanced reliability.
For having better understanding of the invention, description will be made in some detail of the technical background thereof by reference to FIG. 6 which shows in a sectional view a typical capacitive acceleration sensor which can be manufactured, for example, through a semiconductor micromachining process. Referring to the figure, the capacitive acceleration sensor includes an inertial mass member 1 supported on an anchor portion 2 by means of a cantilever 3, stationary electrodes 4 and 5 formed on a supporting member 6 so as to be positioned above and below the inertial mass member 1, respectively. The inertial mass member 1 and the stationary electrodes 4 and 5 cooperate to constitute capacitors 7 and 8, respectively, as shown in an equivalent circuit diagram of FIG. 7. The first and second capacitors 7 and 8 have respective capacitances C1 and C2 and constitute cooperatively a capacitive acceleration sensor device or element 9.
Operation of the capacitive acceleration sensor will be described. It is assumed that an inertial force due to acceleration acts on the inertial mass member 1 in the X-direction. Then, the inertial mass member 1 is caused to displace over a distance u in the X-direction in dependence on the magnitude of the acceleration. As a result of the displacement u of the inertial mass member 1, the capacitance between the inertial mass member 1 and the stationary electrode 5 increases (i.e., C+.DELTA.C, where .DELTA.C represents increment of the capacitance) while the capacitance between the inertial mass member 1 and the other stationary electrode 4 decreases (i.e., C-.DELTA.C).
As a method of converting the change in the capacitance corresponding to the displacement of the inertial mass member 1 into a voltage signal, there may be mentioned, by way of example, a switched capacitor circuit technique disclosed in Rudlf et al's "A BASIC FOR HIGH-RESOLUTION CAPACITIVE MICROACCELEROMETERS, SENSOR & ACTUATOR", A21-A23 (1990), pp. 278-281.
FIG. 8 is a circuit diagram showing a conventional or hitherto known conversion circuit for converting change of capacitance of a capacitive sensor into an electric signal, and FIG. 9 is a timing chart for illustrating operation of switches incorporated in the circuit shown in FIG. 8
Referring to FIG. 8, a capacitive sensor element 9 is implemented in a structure similar to that shown in FIG. 7 and includes the first and second capacitors 7 and 8, wherein the junction or common terminal thereof (i.e., connection node between one ends of the capacitors 7 and 8) is connected to an inversion input terminal of a first stage operational amplifier A1 incorporated in an impedance conversion circuit 10, while the other end of the first capacitor 7 is coupled to a source voltage Vs by way of a switch SW1 and additionally connected to a non-inversion input terminal of the first stage operational amplifier A1 by way of a switch SW2. On the other hand, the other end of the second capacitor 8 is connected to the ground potential (Gnd) via a switch SW4 and additionally to a conductor or wire interconnecting the switch SW2 and the non-inversion input terminal of the first stage operational amplifier A1 by way of a switch SW3. The impedance conversion circuit 10 includes a second stage operational amplifier A2 in addition to the first stage operational amplifier A1, wherein the inversion input terminal of the first stage operational amplifier A1 is connected to the common terminal of the first and second capacitors 7 and 8. The output of the first stage operational amplifier A1 is fed back to the inversion input terminal of the first amplifier A1 via a feedback capacitor 11 across which a switch SW5 is connected in parallel. The non-inversion input terminal of the first stage operational amplifier A1 is connected to a reference voltage source Vr via a holding capacitor 14. The inversion input terminal of the second stage operational amplifier A2 is connected to the output terminal of the first stage operational amplifier A1 by way of a switch SW6 and a fourth capacitor 12, while the non-inversion input terminal of the second stage operational amplifier A2 is connected to the reference voltage Vr and additionally to the fourth capacitor 12 via a switch SW7 The output of the second stage operational amplifier A2 is fed back to the inversion input terminal thereof by way of a fifth capacitor 13 and additionally to the non-inversion input terminal of the first stage operational amplifier A1 via a switch SW8.
The switches SW1, SW4 and SW6 are closed in response to a first timing clock signal .phi.1 illustrated in FIG. 9, while the switches SW2, SW3, SW5, SW7 and SW8 are closed in response to a second clock timing signal .phi.2 also illustrated in FIG. 9.
When the switches SW1 and SW4 are closed or turned on in response to the first clock timing signal .phi.1, the source voltage Vs is applied to the one terminal of the first capacitor 7 constituting a part of the capacitive sensor element 9 by way of the closed switch SW1, and the other terminal of the second capacitor 8 is coupled to the ground potential by way of the closed switch SW4. At that time point, when the junction electrode (common terminal) of the first and second capacitors 7 and 8 is not connected to the inversion input terminal of the first stage operational amplifier A1, electric charge is stored in the first and second capacitors 7 and 8, respectively, in a quantity equal to each other as a result of which there makes appearance at the common terminal of the first and second capacitors 7 and 8 a voltage Vm which can be expressed as follows: ##EQU1## where S represents a sensor sensitivity which can be expressed by EQU S=(C1-C2)/(C1+C2)
For the convenience of discussion, it is assumed that the capacitances C1 and C2 can be expressed as follows: EQU C1=Co/(1-X) EQU C2=Co/(1+X)
where X represents a relative displacement relative to the initial distance between the inertial mass member 1 and the stationary electrodes 4 and 5 (hereinafter also referred to also as the inter-electrode relative displacement), respectively. Thus, the following relation applies valid. EQU S=X
In other words, the sensitivity S of the capacitive sensor element 9 corresponds to or depends on the inter-electrode relative displacement X.
In designing the interface circuit for the capacitive sensor or sensor element 9 it is preferred to extract the voltage signal given by the above-mentioned expression (1) with low impedance to thereby generate an output voltage representing proportionally the interelectrode relative displacement X. However, because the capacitive sensor element 9 is constituted by the capacitors having the capacitances ordinarily on the order of several pico-farads (pF) to several ten pico-farads (pF) and exhibits extremely high output impedance, impedance conversion is performed by using the succeeding impedance conversion circuit 10. Basically, the impedance conversion circuit 10 is so designed as to determine the non-inversion input voltage for the first stage operational amplifier A1 so that the electric charge can be stored in the first and second capacitors 7 and 8, respectively, in an equal quantity.
The conventional conversion circuit described above suffers drawback that the input offset voltage Vos1 of the first stage operational amplifier A1 makes appearance at the output terminal after having been amplified, as can be seen from the expression (2) mentioned below. The capacitance C3 of the third feedback capacitor 11 can not be decreased excessively in order to ensure the stability of the first stage operational amplifier A1. As the sum (C1+C2) of the capacitances C1 and C2 of the first and second capacitors 7 and 8 is selected smaller when compared with the capacitance C3 of the third capacitor 11, the offset voltage Vos1 appearing at the output is amplified by a factor corresponding to the ratio between the sum capacitance (C1+C2) and the capacitance C3. EQU Vout={C1/(C1+C2)}.multidot.Vs+{C3/(C1+C2)-1}.multidot.Vos1 (2)
As a result of this, the temperature dependency of the input offset voltage Vos1 becomes more remarkable, incurring degradation of the temperature characteristic of the output of the sensor to a disadvantage.
Furthermore, in the case where the common terminal 3 of the differential capacitance type sensor element 9 is connected to the ground potential or a fixed potential level, as shown in FIG. 7, the circuit shown in FIG. 8 can not be used as it is, giving rise to a problem.
Besides, because the output of the sensor is amplified in a succeeding operational amplifier with a view enhancing the sensitivity of the sensor, the drift component ascribable to the temperature characteristic of the capacitive sensor element 9 is amplified, incurring noticeable noise in the sensor output signal and thus degrading the reliability of the sensor output signal.
Moreover, because the common terminal 3 of the capacitive sensor element 9 at which the voltage Vm given by the expression (1) makes appearance in dependence on the displacement of the inertial mass member 1 is in the floating state, difficulty will be encountered in the attempt for providing additionally an actuating electrode in opposition to the terminal 3 for thereby actuating the inertial mass member 1 by making use of an electrostatic force acting between the electrodes when a driving voltage Va is applied to the actuating electrode for the purpose of diagnosing the sensor operation. In that case, the effective interelectrode voltage is no more than a difference (Va-Vm) between the voltages Va and Vm. Consequently, sufficiently high actuating voltage can not be made use of, which in turn means that the result of the diagnosis is poor in the reliability, giving rise to a problem.


A disc device includes the following: a traverse base 5 that can be moved between a recording/reproducing position and a standby position, on which an optical pickup 2 and a turntable 1 are mounted; a front cover 3 including a disc carrying surface 3a that carries a disc 4 and an aperture 3b that is formed in the disc carrying surface 3a and allows the turntable 1 to pass through when the traverse base 5 is moved between the recording/reproducing position and the standby position; and centering members 8 for holding and shifting the disc 4 to a position where the center of the disc 4 is aligned with the center of the turntable 1. The loading of a disc can be performed in an easy and highly flexible manner.

In recent years, a DVD recorder capable of recording/reproducing information signals with respect to a DVD has begun to be available rapidly. For more widespread use of the DVD recorder in the future, it has been required to develop a disc device that is usable by anyone and aims for high usability such as universal design. To improve the usability of the disc device, a configuration that can facilitate the loading of a disc in the disc device has been proposed.
A conventional disc device generally employs a "tray system" that allows a tray for carrying a disc to slide in and out. In the disc device using the tray system, a disc is placed on the tray that is drawn out of the device, and then the tray is inserted into the device, thereby loading the disc in the disc device.
A conventional disc device will be described below.
The conventional disc device is known, e.g., from Patent Document 1. In the disc device of Patent Document 1, an opening through which a tray slides in and out is formed in a front panel of the disc device. A disc is placed on the tray that is projected from the opening, and then the disc together with the tray is inserted into a predetermined position (where the disc is attached to or detached from a turntable) inside the disc device.
After the insertion of the disc placed on the tray into the device, the disc is attached on the turntable and rotated at the predetermined rate while being sandwiched between the turntable and a clamper. Information signals are recorded/reproduced with respect to the rotating disc.
For reproduction, e.g., a pickup for reading signals is moved to a track position of an information layer of the disc where the information signals are recorded. Subsequently, the pickup irradiates the information layer with a light beam and detects the light beam reflected from the disc, so that the information signals can be reproduced.
Patent Document 1: JP 4(1992)-67712A

Disc device with particular loading mechanism


A reduced keypad entry method and apparatus provides a method and apparatus for entry of words using a small number of keypresses on a reduced keypad (210) having multiple symbols associated with at least one key. The method and apparatus uses validity rules (242) to rearrange the order of presentation of the multiple alphabet symbols associated with a single key on the keypad (210), automatically eliminates the presentation of invalid alphabet symbols, and allows the entry of additional information such as a tone markers. Additionally, the method and apparatus uses a dictionary (244) to convert phonetic syllables into Chinese characters.

A portable hand-held communication device, such as a cellular telephone, typically has less than fifteen keys available for data entry of information for short messaging and address book features. FIG. 1 shows a prior art reduced keypad 100 for an electronic device. The prior art reduced keypad shown is a standard telephone keypad having ten number keys 110-119, a star (*) key 121, and a pound (#) key 122. For English and many other alphabet languages, the numeric keypad of the telephone is overlaid with an alphabet keypad where three or more letters of the alphabet are associated with each number key. For example, the five (5) key 115 is associated with the letters j-k-l. In some reduced keypad electronic devices, upon entering an alphabet entry mode, a user employs multiple key presses to enter letters to make words and names for use by features such short messaging and address book.
For example, once in alphabet entry mode, a user can employ one keypress to select the first letter associated with a depressed key, two keypresses of the same key to select the second letter associated with the key, three keypresses of the same key to select the third letter associated with the key, and so on. Letters are separated using a confirm key, such as the pound (#) key 122.
Chinese and other character-based languages such as Japanese kanji, however, do not have a manageable number of alphabet letters that can be overlaid onto a numeric keypad. For example, Chinese does not use an alphabet and instead has about 5000 to 7000 commonly-used characters. Advantageously, many phonetic systems have been developed to standardize the pronunciation of, for example, Mandarin Chinese. Several of these phonetic systems use the roman alphabet as phonetic symbols, such as the Wade-Giles and the pinyin systems for Mandarin Chinese, and other phonetic systems use a unique phonetic symbol set, such as the zhuyin system for Mandarin Chinese which has a 37-symbol phonetic alphabet. Cantonese Chinese also has a phonetic system using the roman alphabet.
Although there are over 5000 commonly-used Chinese characters, there are only approximately 400 basic phonetic syllables in Mandarin Chinese speech. Thus, the same Mandarin Chinese phonetic syllable is used by many different Chinese characters. An extreme example is the Mandarin Chinese pinyin word "yi"; this phonetic syllable represents over 100 different Chinese characters, each with a different meaning.
Additionally, Mandarin Chinese uses four standard tones to differentiate meanings. Thus, the same phonetic syllable, when pronounced using a different tone, has a different meaning. Using the phonetic word "yi" as an example, at least 20 characters use the first tone, at least 31 characters use the second tone, at least 16 characters use the third tone, and at least 63 characters use the fourth tone.
Although there exist various methods of entering Chinese characters into a computer system using a full-sized keyboard having keys corresponding to all of the phonetic symbols of one of the various phonetic systems and the four tones, there is a need for a reduced keypad entry method for characters for use in a portable hand-held device such as a cellular telephone.

Reduced keypad entry apparatus and method


A pin support structure comprising a first foil having opening and a second foil having openings. The first foil is secured to a foil support frame and the second foil is secured to a foil support frame. The foils are maintained in spaced apart relationship by a separation frame. The holes of the foil are in registration with the holes of the foil. The holes in the foils are formed by electro-chemical etching. A pin has a base end and a support end.

1. Field of the Invention
A pin support fixture for supporting the side of a pc board which side has electronic components thereon.
2. Discussion of the Relevant Art
In pc board assembly, electronic components are mounted on both sides of the board. When components are mounted on a first side, side 1, the other side, side 2, is simply supported on a planar surface. To mount components on side 2 the card is inverted. Side 1 with the components can be supported on a mirror image molded surface but usually a table or fixture having pins extending upwardly therefrom supports the board. The pins contact the side 1 where there are no components (otherwise referred to as a 'bare board' location). The positioning of the pins is generally through a 'blind' selection process. Pins are randomly inserted and if they contact the side 1 after being inserted a known distance from the plate to the surface of the side 1 they are secured. Most methods require machined metal tables and the total pin support fixture is generally about twenty (20) pounds.

Fine resolution pin support fixture with light weight design


The present invention is a system for controlling exclusive access by control programs (30) to system resources (52). A system in accordance with the invention includes a plurality of addressable locations (12, 14, 16, 18, 20 and 22) in the system; a communication system (24) connecting the addressable locations which transmits communications between the addressable locations; a plurality of machines (26), the machines being located at at least one of the addressable locations; a plurality of control programs which use resources including a plurality of machine control programs, each machine control program controlling at least one machine; and a plurality of resource managers (32), the resource managers being located at a plurality of the addressable locations, each resource manager communicating over the communication system with at least one other resource manager, and the plurality of resource managers arbitrating which control program of the plurality of control programs is given exclusive use of at least one resource during execution of the control program.

1. Field of the Invention
The present invention relates to systems which control machines or processes to share common resources and more particularly, to a system which controls machines or processes so one machine or process control program at a time is given exclusive use of at least one resource.
2. Description of the Prior Art
FIG. 1 shows the prior art interlock mechanism used in traditional robotic and other machine control applications. Two robots, A and B, for example, are interconnected not directly, but via a programmable logic controller (PLC). The actual interlock logic is inside the PLC, and the two robots use discrete I/O to communicate with the PLC.
When Robot A wishes to acquire the protected resource (in this example, the resource is a shared workspace), it sets Request A true. Robot B does the same. However, the PLC only permits one grant line to go true. One robot can proceed while the other waits for its grant to go true. In this way, there is presumably no collision between the two robots.
However, this mechanism has several drawbacks in actual practice:                1) PLC scan time causes timing problems.—When either side uses a resource, then its request line is cleared (OUT Request X=FALSE) at the end of the program section, the Grant line for that robot does not immediately go false. It will go false after the next PLC logic scan. If the same program loops back to retake the resource before the grant line goes false, the program will continue thinking the resource is available. After the scan delay, the PLC will grant control to the opposite side, and both sides will assume the resource simultaneously. If that resource is a shared workspace for example, the two robots will collide in that workspace. This problem is typically solved with delays built into the robot programs, making them inefficient.        2) Request and Wait are not atomic—The real problem in item 1 above is that with simple I/O communication with the PLC, the request operation and the wait for operation are not atomic (indivisible). In fact the wait for may return as a result of a previous request, not for the current request. The concept of a mutex (mutual exclusion) object is well known in computer science and well known in computer programming. Using such a mechanism, a program typically requests a resource, and the arbitrator for the mutex does not return from the request until the resource is available. By using a function call to both request the resource and return ownership of the resource, these operations are indivisible from the program's point of view. In this case the PLC does implement a proper mutex. However, the two robot controllers communicate with the PLC via simple I/O bits, and the atomic nature of the mutex operations is destroyed.        3) Only two programs can share a resource.—The interlock technique described here and commonly used in the industry only permits two programs to share the resource. If more than two programs need to share the resource, then more complicated PLC logic must be used for that special case.        4) Deadlock detection—When multiple programs share multiple resources, it is possible for two or more programs to end up in deadlock, with each program owning a resource while needing one owned by another. The PLC I/O interlock technique typically used in industry provides no way to detect this deadlock situation and considerable debugging time is often needed to find the problem.        5) Deadlock prevention—There are well known techniques from computer science for both detecting and helping to prevent deadlocks. However, the PLC I/O interlock technique has no way to implement these techniques. Computer operating systems provide various mutex mechanisms for multiple programs running on a single computer. In multi-processor systems, the operating system for the multi-processor system provides some mutex mechanism for sharing resources between programs on the system. However, there is no existing system that provides for a reliable interlock mechanism that solves all the above listed problems for control programs running on separate controllers connected only by a standard communications network and with potentially disparate operating systems on the separate controllers.
U.S. Pat. No. 6,212,444 entitled "Method of avoiding interference of industrial robot" discloses a distance based method of avoiding the collision of a robot with another robot or cooperating apparatus. Each robot or device senses its own entrance into a commonly defined geometric region either by command or by interpolation along a path. When entering a region, each robot or apparatus sends a signal to prevent the other from entering, by causing it to stop and wait.
The method of U.S. Pat. No. 6,212,444 has disadvantages, some common to the prior art of FIG. 1 discussed above:                1) The signals sent between the robot and cooperating apparatus do not implement a mutually exclusive interlock. Though a collision is avoided, a potential deadlock is not. This type of deadlock is possible because there is no arbitrator to assign ownership of the shared resource. Thus, each apparatus can be stopped by the other, and each will wait forever for the other to proceed.        2) The method is based only on distance of the machines. The method cannot be used for arbitrary resource sharing.        3) There is no deadlock detection or prevention mechanism.

System controlling exclusive access by control programs to system resources


A multi-chip semiconductor package and a fabrication method thereof are provided. At least one first chip is mounted on and electrically connected to an upper surface of a substrate via solder bumps. A preformed package structure having a second chip and a first encapsulation body is mounted on the upper surface of the substrate, wherein outer leads of the preformed package structure are exposed from the first encapsulation body and electrically connected to the upper surface of the substrate. The first encapsulation body, outer leads and substrate form a space where the first chip is received, and a gap is present between the first chip and the first encapsulation body. A second encapsulation body is formed on the upper surface of the substrate to encapsulate the first chip, solder bumps and preformed package structure. A plurality of solder balls are implanted on the lower surface of the substrate.

In accordance with electronic products being developed with compact size, light weight and high efficiency, semiconductor packages have been correspondingly reduced in profile and preferably incorporated with multiple chips to be suitable for use with the electronic products. Such structure with multiple semiconductor chips being mounted in a single package is customarily referred to as a multi-chip semiconductor package, wherein the multiple chips can be vertically stacked on a chip carrier (such as a substrate or lead frame) or individually attached to the substrate. The multi-chip package structure has a primary advantage for providing the semiconductor package with effectively enhanced or multiplied electrical and operational performances, making it suitably used in the highly efficient electronic product.
U.S. Pat. Nos. 5,696,031 and 5,973,403 have disclosed a multi-chip semiconductor package. Referring to FIG. 5, in this semiconductor package, a first chip 21 is mounted on a surface of a substrate 20 in a flip-chip manner that an active surface 210 of the first chip 21 faces downwards and is electrically connected to the substrate 20 via a plurality of solder bumps 22. Then, a second chip 23 is attached to a non-active surface 211 of the first chip 21 and is electrically connected to the substrate 20 via a plurality of bonding wires 24. An encapsulation body 25 is formed on the substrate 20 to encapsulate the first chip 21, second chip 23 and bonding wires 24. Finally, a plurality of solder balls 26 are implanted on an opposite surface of the substrate 20. This completes fabrication of the multi-chip semiconductor package. Since the wire-bonding process performed on the second chip 23 would generate shocks that may cause cracks of the solder bumps 22, an underfill process is carried out between the first chip 21 and the substrate 20 to fill an insulating material (such as a resin material, etc.) in gaps between the adjacent solder bumps 22, so as to enhance the mechanical strength of the solder bumps 22 and prevent them from cracks due to the shocks generated by the wire-bonding process.
However, during the underfill process for the above semiconductor package, the procedure of filling the insulating material may easily contaminate predetermined positions (such as bond fingers) on the substrate for connecting the bonding wires, and the bonding wires cannot be firmly bonded to the contaminated bond fingers, such that the yield of the wire-bonding process and the quality of electrical connection between the second chip and the substrate would be degraded, and the reliability of the entire semiconductor package is thus deteriorated. Moreover, for the second chip that is electrically connected to the substrate via the bonding wires, since the second chip is directly incorporated in the semiconductor package with the quality and yield of the second chip being unknown, a known good die (KGD) issue is produced. In other words, if the second chip not passing a burn-in test incurs quality defects, the entire package having such second chip would fail and the product yield is reduced.
U.S. Patent Publication No. 2004/0113275 has disclosed another multi-chip semiconductor package. As shown in FIG. 6, this semiconductor package allows a first chip 31 to be mounted on a surface of a substrate 30 in a flip-chip manner, wherein an active surface 310 of the first chip 31 faces downwards and is electrically connected to the substrate 30 via a plurality of solder bumps 32. An insulating material (such as a resin material, etc.) is filled in gaps between the adjacent solder bumps 32 using an underfill technique. Then, a land grid array (LGA) package structure 33 is attached to a non-active surface 311 of the first chip 31 in an inverted manner, and a substrate 330 of the LGA package structure 33 is electrically connected to the substrate 30 via a plurality of bonding wires 34. An encapsulation body 35 is formed on the substrate 30 to encapsulate the first chip 31, LGA package structure 33 and bonding wires 34. Finally, a plurality of solder balls 36 are implanted on an opposite surface of the substrate 30. This completes fabrication of the multi-chip semiconductor package.
Although the above fabrication method may solve the KGD problem, the multi-chip semiconductor package shown in FIG. 6 still have the similar drawback to that shown in FIG. 5. As the underfill process is required to fill the gaps between the adjacent solder bumps 32 with the insulating material so as to enhance the mechanical strength of the solder bumps 32 and prevent them from cracks due to shocks during the wire-bonding process, the procedure of filling the insulating material may easily contaminate predetermined positions (such as bond fingers) on the substrate 30 for connecting the bonding wires 34, and the bonding wires 34 cannot be firmly bonded to the contaminated bond fingers, thereby degrading the yield of the wire-bonding process and the quality of electrical connection between the LGA package structure 33 and the substrate 30, as well as deteriorating the reliability of the entire semiconductor package.
Therefore, the problem to be solved here is to provide a multi-chip semiconductor package, which can prevent predetermined positions for electrical connection on a substrate from contamination and eliminate a KGD issue so as to assure the reliability and yield of the semiconductor package.

Siliconware Precision Industries Co., Ltd.


There is provided an improved redundancy method for a communication network. The invention is based on the insight that a hitless failover can be performed by at the receiving node using a single common indexed play-out buffer in which a selective reconstruction of the transported data stream utilizing individual pieces, i.e. frames or packages, of a data stream received over multiple links is performed.

A standard approach to increase redundancy in a node to node communication for connections in a communication network, such as an Asynchronous Serial Interface (ASI) connection or an Ethernet connection, is to use duplicated transmission paths, channels or links, between the communicating nodes, which herein after is referred to as a 1+1 connection. Typically, a receiving node is arranged to receive replicas of a data stream, a stream of packets, from a transmitting node. The replicated data streams are transported via a main link and via a backup link to the receiving node. Note that a link may refer to a sequence of intermediate node to node communications. Based on the quality or status of the communication over the respective link, a select mechanism in the receiving node determines which one of the links should be selected as a main link from which an output data stream of the node is forwarded to another node or an application associated with the node. Thus, the general idea of such 1+1 connection is that if the main link suffers malfunction, a failover can be performed to the backup link. However, due to for instance different time delays for the communication over the main link and the backup link, if the main link suddenly malfunctions, hits in the form of data loss or duplicated data in the forwarded data stream are normally incurred at the failover.
Instead of switching the communication link as a whole at a malfunction, it has been shown that the selection of which replicated data to forward can be performed on basis of identifiers included in the respective packets of a data stream. European Patent Application Publ. No. EP 0854 610 A2 discloses a redundancy method for an Ethernet communication between a plurality of nodes which are connected to each other through a first and a second independent Ethernet communication line. Identical data packets, each to which a data identifier for identifying data contents has been added, are transferred from a transmitting node to a receiving node over both communication lines. At reception, data transferred over the first and the second link is temporarily stored in a respective buffer, and in the receiving node it is determined on basis of the data identifier, which data transferred over the two respective communication lines that has arrived first, and which is therefore accepted as first reception data for further use. This provides a redundancy method with minimized introduced delay for the respective data portions while maintaining redundancy in the connection.


This invention relates to a micromachined fluid ejector array having a fluid reservoir bounded at one side by an elastic membrane having scalable arrays of orifices arranged between concentric piezoelectric transducers, and at another side by a top cover supported by surrounding walls. By actuating neighboring concentric piezoelectric transducers, the scalable array of orifices arranged between the actuated neighboring concentric piezoelectric transducers deflect to eject fluid droplets. Also disclosed is a micromachined fluid ejector array having a fluid reservoir bounded at one side by an elastic membrane having scalable arrays of orifices arranged between concentric piezoelectric transducers, and at another side by a top cover supported by surrounding walls. A piezoelectric layer is bonded on top of the top cover. By actuating the piezoelectric layer bonded on top of the top cover, the scalable arrays of orifices arranged between the neighboring concentric piezoelectric transducers deflect in phase to eject fluid droplets.

Fluid droplet ejectors have been mostly associated with the printing business. Nozzles of various kinds have been reported in many publications and are commercially available. These nozzles are typically used to allow the formation and control of small ink droplets that result in high quality printing on demand.
Typically, an ink printhead has apertures or nozzles from which ink droplets are expelled onto a print medium, and the ink is routed internally through the printhead. Conventional methods of ejecting inks onto the print medium include piezoelectric transducers and bubbles formed by heat pulses to force fluid out of the nozzles. In situations where a printhead includes multiple nozzles, if one desires to selectively expel ink droplets from a specific nozzle and not the other nozzles, conventional solutions known in the art, isolate the nozzles from each other by long narrow passages that damp pressure surges in the ink fluid provided to the nozzles from a common source. Heaters can also be located at each nozzle, for the purpose of reducing ink viscosity at a specific nozzle. Thus, when a droplet is to be ejected from a specific nozzle, the heater at that nozzle is activated to heat ink at the nozzle so that when a pressure pulse is applied to the ink fluid, the ink viscosity at the nozzle is reduced enough so that a droplet of ink will be expelled from the nozzle, while the higher viscosity of the (colder) ink at the other nozzles remains high enough to prevent ejection of ink droplets from those other nozzles.
In U.S. Pat. No. 6,712,455, it is reported that a printhead includes a common ink chamber or reservoir bounded on one side by a membrane having nozzle apertures. The membrane forms a print face of the printhead. Piezoelectric elements (piezos) are located on the membrane near the nozzles. The piezos flex segments of the membrane surrounding the nozzles to eject ink droplets from the nozzle apertures. Ribs are also provided on the membrane and define boundaries of the membrane segments corresponding to the nozzles. The ribs can isolate each nozzle from the other nozzles, in two ways. First, the ribs act as stiffeners so that when piezos attached to one membrane segment flex that membrane segment, the other membrane segments are not significantly flexed. Second, when the ribs are provided on an interior surface of the membrane, they deflect the pressure pulse in the ink fluid from a flexing membrane segment, upwards, away from adjacent membrane segments/nozzles.
Micromachined droplet ejectors have also been reported in U.S. Pat. Nos. 6,445,109 and 6,474,786. This type of droplet ejectors include a cylindrical reservoir closed at one end with an elastic membrane including at least one aperture. A bulk actuator at the other end for actuating the fluid for ejection through the aperture. The ejector array is a micromachined two-dimensional array droplet ejector. The ejector includes a two-dimensional array of elastic membranes having orifices closing the ends of cylindrical fluid reservoirs. The fluid in the ejectors is bulk actuated to set up pressure waves in the fluid which cause fluid to form a meniscus at each orifice. Selective actuation of the membranes ejects droplets. In an alternative mode of operation, the bulk pressure wave has sufficient amplitude to eject droplets while the individual membranes are actuated to selectively prevent ejection of droplets.
These conventional and micromachined print heads or fluid ejectors suffer from various disadvantages. First, they usually require a large interconnected reservoir to store the ink or fluid. The fluid can only be ejected when this reservoir is fully filled, which usually results in large waste because these are considered dead volume. Second, the print head or ejector array has many long, narrow passages for transmitting ink to a particular nozzle. Third, many of these print heads and fluid ejectors address the need to selectively eject fluid from one particular nozzle. Because of manufacturing differences, however, these devices are not suitable to uniformly eject fluid in pico-liter quantities.
In biochemistry or related applications, there is a need for fluid ejectors that can control the fluid ejection at pico-liter level reliably. The fluid ejector is also required to have small dead volume so that there is least waste of biochemical reagents. In addition, it needs to eject fluid droplets uniformly across all orifices without satellite drops.