Candidate answers responsive to a user query are analyzed using a natural language engine to determine appropriate answers from an electronic database. The system and methods are useful for Internet based search engines, as well as distributed speech recognition systems such as a client-server system. The latter are typically implemented on an intranet or over the Internet based on user queries at his/her computer, a PDA, or a workstation using a speech input interface.

The INTERNET, and in particular, the World-Wide Web (WWW, is growing in popularity and usage for both commercial and recreational purposes, and this trend is expected to continue. This phenomenon is being driven, in part, by the increasing and widespread use of personal computer systems and the availability of low cost INTERNET access.
The emergence of inexpensive INTERNET access devices and high speed access techniques such as ADSL, cable modems, satellite modems, and the like, are expected to further accelerate the mass usage of the WWW.
Accordingly, it is expected that the number of entities offering services, products, etc., over the WWW will increase dramatically over the coming years. Until now, however, the INTERNET "experience" for users has been limited mostly to non-voice based input/output devices, such as keyboards, intelligent electronic pads, mice, trackballs, printers, monitors, etc. This presents somewhat of a bottleneck for interacting over the WWW for a variety of reasons.
First, there is the issue of familiarity. Many kinds of applications lend themselves much more naturally and fluently to a voice-based environment. For instance, most people shopping for audio recordings are very comfortable with asking a live sales clerk in a record store for information on titles by a particular author, where they can be found in the store, etc. While it is often possible to browse and search on one's own to locate items of interest, it is usually easier and more efficient to get some form of human assistance first, and, with few exceptions, this request for assistance is presented in the form of a oral query. In addition, many persons cannot or will not, because of physical or psychological barriers, use any of the aforementioned conventional I/O devices. For example, many older persons cannot easily read the text presented on WWW pages, or understand the layout/hierarchy of menus, or manipulate a mouse to make finely coordinated movements to indicate their selections. Many others are intimidated by the look and complexity of computer systems, WWW pages, etc., and therefore do not attempt to use online services for this reason as well.
Thus, applications which can mimic normal human interactions are likely to be preferred by potential on-line shoppers and persons looking for information over the WWW. It is also expected that the use of voice-based systems will increase the universe of persons willing to engage in e-commerce, e-learning, etc. To date, however, there are very few systems, if any, which permit this type of interaction, and, if they do, it is very limited. For example, various commercial programs sold by IBM (VIAVOICE™) and Kurzweil (DRAGON™) permit some user control of the interface (opening, closing files) and searching (by using previously trained URLs) but they do not present a flexible solution that can be used by a number of users across multiple cultures and without time consuming voice training. Typical prior efforts to implement voice based functionality in an INTERNET context can be seen in U.S. Pat. No. 5,819,220 incorporated by reference herein.
Another issue presented by the lack of voice-based systems is efficiency. Many companies are now offering technical support over the INTERNET, and some even offer live operator assistance for such queries. While this is very advantageous (for the reasons mentioned above) it is also extremely costly and inefficient, because a real person must be employed to handle such queries. This presents a practical limit that results in long wait times for responses or high labor overheads. An example of this approach can be seen U.S. Pat. No. 5,802,526 also incorporated by reference herein. In general, a service presented over the WWW is far more desirable if it is "scalable," or, in other words, able to handle an increasing amount of user traffic with little if any perceived delay or troubles by a prospective user.
In a similar context, while remote learning has become an increasingly popular option for many students, it is practically impossible for an instructor to be able to field questions from more than one person at a time. Even then, such interaction usually takes place for only a limited period of time because of other instructor time constraints. To date, however, there is no practical way for students to continue a human-like question and answer type dialog after the learning session is over, or without the presence of the instructor to personally address such queries.
Conversely, another aspect of emulating a human-like dialog involves the use of oral feedback. In other words, many persons prefer to receive answers and information in audible form. While a form of this functionality is used by some websites to communicate information to visitors, it is not performed in a real-time, interactive question-answer dialog fashion so its effectiveness and usefulness is limited.
Yet another area that could benefit from speech-based interaction involves so-called "search" engines used by INTERNET users to locate information of interest at web sites, such as the those available at YAHOO®.com, METACRAWLER®.com, EXCITE®.com, etc. These tools permit the user to form a search query using either combinations of keywords or metacategories to search through a web page database containing text indices associated with one or more distinct web pages. After processing the user's request, therefore, the search engine returns a number of hits which correspond, generally, to URL pointers and text excerpts from the web pages that represent the closest match made by such search engine for the particular user query based on the search processing logic used by search engine. The structure and operation of such prior art search engines, including the mechanism by which they build the web page database, and parse the search query, are well known in the art. To date, applicant is unaware of any such search engine that can easily and reliably search and retrieve information based on speech input from a user.
There are a number of reasons why the above environments (e-commerce, e-support, remote learning, INTERNET searching, etc.) do not utilize speech-based interfaces, despite the many benefits that would otherwise flow from such capability. First, there is obviously a requirement that the output of the speech recognizer be as accurate as possible. One of the more reliable approaches to speech recognition used at this time is based on the Hidden Markov Model (HMM)—a model used to mathematically describe any time series. A conventional usage of this technique is disclosed, for example, in U.S. Pat. No. 4,587,670 incorporated by reference herein. Because speech is considered to have an underlying sequence of one or more symbols, the HMM models corresponding to each symbol are trained on vectors from the speech waveforms. The Hidden Markov Model is a finite set of states, each of which is associated with a (generally multi-dimensional) probability distribution. Transitions among the states are governed by a set of probabilities called transition probabilities. In a particular state an outcome or observation can be generated, according to the associated probability distribution. This finite state machine changes state once every time unit, and each time t such that a state j is entered, a spectral parameter vector Ot is generated with probability density Bj(Ot). It is only the outcome, not the state visible to an external observer and therefore states are "hidden" to the outside; hence the name Hidden Markov Model. The basic theory of HMMs was published in a series of classic papers by Baum and his colleagues in the late 1960's and early 1970's. HMMs were first used in speech applications by Baker at Carnegie Mellon, by Jelenik and colleagues at IBM in the late 1970's and by Steve Young and colleagues at Cambridge University, UK in the 1990's. Some typical papers and texts are as follows:
1. L. E. Baum, T. Petrie, "Statistical inference for probabilistic functions for finite state Markov chains", Ann. Math. Stat., 37: 1554-1563, 1966
2. L. E. Baum, "An inequality and associated maximation technique in statistical estimation for probabilistic functions of Markov processes", Inequalities 3: 1-8, 1972
3. J. H. Baker, "The dragon system—An Overview", IEEE Trans. on ASSP Proc., ASSP-23(1): 24-29, February 1975
4. F. Jeninek et al, "Continuous Speech Recognition: Statistical methods" in Handbook of Statistics, II, P. R. Kristnaiad, Ed. Amsterdam, The Netherlands, North-Holland, 1982
5. L. R. Bahl, F. Jeninek, R. L. Mercer, "A maximum likelihood approach to continuous speech recognition", IEEE Trans. Pattern Anal. Mach. Intell., PAMI-5: 179-190, 1983
6. J. D. Ferguson, "Hidden Markov Analysis: An Introduction", in Hidden Markov Models for Speech, Institute of Defense Analyses, Princeton, N.J. 1980.
7. H. R. Rabiner and B. H. Juang, "Fundamentals of Speech Recognition", Prentice Hall, 1993.
8. H. R. Rabiner, "Digital Processing of Speech Signals", Prentice Hall, 1978.
More recently research has progressed in extending HMM and combining HMMs with neural networks to speech recognition applications at various laboratories. The following is a representative paper:
9. Nelson Morgan, Herve Bourlard, Steve Renals, Michael Cohen and Horacio Franco (1993), Hybrid Neural Network/Hidden Markov Model Systems for Continuous Speech Recognition. Journal of Pattern Recognition and Artificial Intelligence, Vol. 7, No. 4 pp. 899-916. Also in I. Guyon and P. Wang editors, Advances in Pattern Recognition Systems using Neural Networks, Vol. 7 of a Series in Machine Perception and Artificial Intelligence. World Scientific, February 1994.
All of the above are hereby incorporated by reference. While the HMM-based speech recognition yields very good results, contemporary variations of this technique cannot guarantee a word accuracy requirement of 100% exactly and consistently, as will be required for WWW applications for all possible all user and environment conditions. Thus, although speech recognition technology has been available for several years, and has improved significantly, the technical requirements have placed severe restrictions on the specifications for the speech recognition accuracy that is required for an application that combines speech recognition and natural language processing to work satisfactorily.
In contrast to word recognition, Natural language processing (NLP) is concerned with the parsing, understanding and indexing of transcribed utterances and larger linguistic units. Because spontaneous speech contains many surface phenomena such as disfluencies,—hesitations, repairs and restarts, discourse markers such as 'well' and other elements which cannot be handled by the typical speech recognizer, it is the problem and the source of the large gap that separates speech recognition and natural language processing technologies. Except for silence between utterances, another problem is the absence of any marked punctuation available for segmenting the speech input into meaningful units such as utterances. For optimal NLP performance, these types of phenomena should be annotated at its input. However, most continuous speech recognition systems produce only a raw sequence of words. Examples of conventional systems using NLP are shown in U.S. Pat. Nos. 4,991,094, 5,068,789, 5,146,405 and 5,680,628, all of which are incorporated by reference herein.
Second, most of the very reliable voice recognition systems are speaker-dependent, requiring that the interface be "trained" with the user's voice, which takes a lot of time, and is thus very undesirable from the perspective of a WWW environment, where a user may interact only a few times with a particular website. Furthermore, speaker-dependent systems usually require a large user dictionary (one for each unique user) which reduces the speed of recognition. This makes it much harder to implement a real-time dialog interface with satisfactory response capability (i.e., something that mirrors normal conversation—on the order of 3-5 seconds is probably ideal). At present, the typical shrink-wrapped speech recognition application software include offerings from IBM (VIAVOICE™) and Dragon Systems (DRAGON™). While most of these applications are adequate for dictation and other transcribing applications, they are woefully inadequate for applications such as NLQS where the word error rate must be close to 0%. In addition these offerings require long training times and are typically are non client-server configurations. Other types of trained systems are discussed in U.S. Pat. No. 5,231,670 assigned to Kurzweil, and which is also incorporated by reference herein.
Another significant problem faced in a distributed voice-based system is a lack of uniformity/control in the speech recognition process. In a typical stand-alone implementation of a speech recognition system, the entire SR engine runs on a single client. A well-known system of this type is depicted in U.S. Pat. No. 4,991,217 incorporated by reference herein. These clients can take numerous forms (desktop PC, laptop PC, PDA, etc.) having varying speech signal processing and communications capability. Thus, from the server side perspective, it is not easy to assure uniform treatment of all users accessing a voice-enabled web page, since such users may have significantly disparate word recognition and error rate performances. While a prior art reference to Gould et al.—U.S. Pat. No. 5,915,236—discusses generally the notion of tailoring a recognition process to a set of available computational resources, it does not address or attempt to solve the issue of how to optimize resources in a distributed environment such as a client-senTer model. Again, to enable such voice-based technologies on a wide-spread scale it is far more preferable to have a system that harmonizes and accounts for discrepancies in individual systems so that even the thinnest client is supportable, and so that all users are able to interact in a satisfactory manner with the remote server running the e-commerce, e-support and/or remote learning application.
Two references that refer to a distributed approach for speech recognition include U.S. Pat. Nos. 5,956,683 and 5,960,399 incorporated by reference herein. In the first of these, U.S. Pat. No. 5,956,683—Distributed Voice Recognition System (assigned to Qualcomm) an implementation of a distributed voice recognition system between a telephony-based handset and a remote station is described. In this implementation, all of the word recognition operations seem to take place at the handset. This is done since the patent describes the benefits that result from locating of the system for acoustic feature extraction at the portable or cellular phone in order to limit degradation of the acoustic features due to quantization distortion resulting from the narrow bandwidth telephony channel. This reference therefore does not address the issue of how to ensure adequate performance for a very thin client platform. Moreover, it is difficult to determine, how, if at all, the system can perform real-time word recognition, and there is no meaningful description of how to integrate the system with a natural language processor.
The second of these references—U.S. Pat. No. 5,960,399—Client/Server Speech Processor/Recognizer (assigned to GTE) describes the implementation of a HMM-based distributed speech recognition system. This reference is not instructive in many respects, however, including how to optimize acoustic feature extraction for a variety of client platforms, such as by performing a partial word recognition process where appropriate. Most importantly, there is only a description of a primitive server-based recognizer that only recognizes the user's speech and simply returns certain keywords such as the user's name and travel destination to fill out a dedicated form on the user's machine. Also, the streaming of the acoustic parameters does not appear to be implemented in real-time as it can only take place after silence is detected. Finally, while the reference mentions the possible use of natural language processing (column 9) there is no explanation of how such function might be implemented in a real-time fashion to provide an interactive feel for the user.
Companies such as Nuance Communications and Speech Works which up till now are the leading vendors that supply speech and natural language processing products to the airlines and travel reservations market, rely mainly on statistical and shallow semantics to understand the meaning of what the users says. Their successful strategy is based on the fact that this shallow semantic analysis will work quite well in the specific markets they target. Also to their advantage, these markets require only a limited amount to language understanding.
For future and broader applications such as customer relationship management or intelligent tutoring systems, a much deeper understanding of language is required. This understanding will come from the application of deep semantic analysis. Research using deep semantic techniques is today a very active field at such centers as Xerox Palo Alto Research Center (PARC), IBM, Microsoft and at universities such as Univ. of Pittsburg [Litman, 2002], Memphis [Graesser, 2000], Harvard [Grosz, 1993] and many others.
In a typical language understanding system there is typically a parser that precedes the semantic unit. Although the parser can build a hierarchical structure that spans a single sentence, parsers are seldom used to build up the hierarchical structure of the utterances or text that spans multiple sentences. The syntactic markings that guide parsing inside a sentence is either weak or absent in a typical discourse. So for a dialog-based system that expects to have smooth conversational features, the emphasis of the semantic decoder is not only on building deeper meaning structures from the shallow analyses constructed by the parser, but also on integrating the meanings of the multiple sentences that constitute the dialog.
Up till now there are two major research paths taken in deep semantic understanding of language: informational and intentional. In the informational approach, the focus is on the meaning that comes from the semantic relationships between the utterance-level propositions (e.g. effect, cause, condition) whereas with the intentional approach, the focus is on recognizing the intentions of the speaker (e.g. inform, request, propose).
Work following the informational approach focuses on the question of how the correct inferences are drawn during comprehension given the input utterances and background knowledge. The earliest work tried to draw all possible inferences [Reiger, 1974; Schank, 1975; Sperber & Wilson, 1986] and in response to the problem of combinatorial explosion in doing so, later work examined ways to constrain the reasoning [DeJong, 1977; Schank et al., 1980; Hobbs, 1980]. In parallel with this work, the notions of conversational implicatures (Grice, 1989) and accomodation [Lewis, 1979] were introduced. Both are related to inferences that are needed to make a discourse coherent or acceptable. These parallel lines of research converged into abductive approaches to discourse interpretation [e.g., Appelt & Pollack,1990; Charniak, 1986; Hobbs et al., 1993; McRoy & Hirst, 1991; Lascarides & Asher, 1991; Lascarides & Oberlander, 1992; Rayner & Alshawi, 1992]. The informational approach is central to work in text interpretation.
The intentional approach draws from work on the relationship between utterances and their meaning [Grice, 1969] and work on speech act theory [Searle, 1969] and generally employs artificial intelligence planning tools. The early work considered only individual plans [e.g., Power, 1974; Perrault & Allen, 1980; Hobbs & Evans, 1980; Grosz & Sidner, 1986; Pollack, 1986] whereas now there is progress on modeling collaborative plans with joint intentions [Grosz & Kraus, 1993; Lochbaum, 1994]. It is now accepted that the intentional approach is more appropriate for conversational dialog-based systems since the collaborative aspect of the dialog has to be captured and retained.
Present research using deep semantic techniques may employ a semantic interpreter which uses prepositions as its input propositions extracted by semantic concept detectors of a grammar-based sentence understanding unit. It then combines these propositions from multiple utterances to form larger units of meaning and must do this relative to the context in which the language was used.
In conversational dialog applications such as an intelligent tutoring system (ITS), where there is a need for a deep understanding of the semantics of language, hybrid techniques are used. These hybrid techniques combine statistical methods (e.g., Latent Semantic Analysis) for comparing student inputs with expected inputs to determine whether a question was answered correctly or not [e.g., Graesser et al., 1999] and the extraction of thematic roles based on the FrameNet [Baker, et al, 1998] from a student input [Gildea & Jurafsky, 2001].
The aforementioned cited articles include:                Appelt, D. & Pollack, M. (1990). Weighted abduction for plan ascription. Menlo Park, Calif.: SR1 International. Technical Note 491.        Baker, Collin F., Fillmore, Charles J., and Lowe, John B. (1998): The Berkeley FrameNet project. In Prceedings of the COLING-ACL, Montreal, Canada.        Charniak, E. (1993). Statistical Language Analysis. Cambridge: Cambridge University Press.        Daniel Gildea and Daniel Jurafsky. 2002. Automatic Labeling of Semantic Roles. Computational Linguistics 28:3, 245-288.        Dejong, G. (1977). Skimming newspaper stories by computer. New Haven, Conn.: Department of Computer Science, Yale University. Research Report 104.        FrameNet: Theory and Practice. Christopher R. Johnson et al, http://www.icsi.berkeley.edu/˜framenet/book/book.html        Graesser, A. C., Wiemer-Hastings, P., Wiemer-Hastings, K., Harter, D., Person, N., and the TRG (in press). Using latent semantic analysis to evaluate the contributions of students in AutoTutor. Interactive Learning Environments.        Graesser, A., Wiemer-Hastings, K., Wiemer-Hastings, P., Kreuz, R., & the Tutoring Research Group (2000). AutoTutor: A simulation of a human tutor, Journal of Cognitive Systems Research, 1,35-51.        Grice, H. P. (1969). Utterer's meaning and intentions. Philosophical Review, 68(2):147-177.        Grice, H. P. (1989). Studies in the Ways of Words. Cambridge, Mass.: Harvard University Press.        Grosz, B. & Kraus, S. (1993). Collaborative plans for group activities. In Proceedings of the Thirteenth International Joint Conference on Artificial Intelligence (IJCAI '93), Chambery, France (vol. 1, pp. 367-373).        Grosz, B. J. & Sidner, C. L. (1986). Attentions, intentions and the structure of discourse. Computational Linguistics, 12, 175-204.        Hobbs, J. & Evans, D. (1980). Conversation as planned behavior. Cognitive Science 4(4), 349-377.        Hobbs, J. & Evans, D. (1980). Conversation as planned behavior. Cognitive Science 4(4), 349-377.        Hobbs, J., Stickel, M., Appelt, D., & Martin, P. (1993). Interpretation as abduction. Artificial Intelligence 63(1-2), 69-142.        Lascarides, A. & Asher, N. (1991). Discourse relations and defeasible knowledge. In Proceedings of the 29th Annual Meeting of the Association for Computational Linguistics (ACL '91), Berkeley, Calif. (pp. 55-62).        Lascarides, A. & Oberlander, J. (1992). Temporal coherence and defeasible knowledge. Theoretical Linguistics, 19.        Lewis, D. (1979). Scorekeeping in a language game. Journal of Philosophical Logic 6, 339-359.        Litman, D. J., Pan, Shimei, Designing and evaluating an adaptive spoken dialogue system, User Modeling and User Adapted Interaction, 12, 2002.        Lochbaum, K. (1994). Using Collaborative Plans to Model the Intentional Structure of Discourse. PhD thesis, Harvard University.        McRoy, S. & Hirst, G. (1991). An abductive account of repair in conversation. AAAI Fall Symposium on Discourse Structure in Natural Language Understanding and Generation, Asilomar, Calif. (pp. 52-57).        Perrault, C. & Allen, J. (1980). A plan-based analysis of indirect speech acts. American Journal of Computational Linguistics, 6(3-4), 167-182.        Pollack, M. (1986). A model of plan inference that distinguishes between the beliefs of actors and observers. In Proceedings of 24th Annual Meeting of the Association for Computational Linguistics, New York (pp. 207-214).        Power, R. (1974). A Computer Model of Conversation. PhD. thesis, University of Edinburgh, Scotland.        Rayner, M. & Alshawi, H. (1992). Deriving database queries from logical forms by abductive definition expansion. In Proceedings of the Third Conference of Applied Natural Language Processing, Trento, Italy (pp. 1-8).        Reiger, C. (1974). Conceptual Memory: A Theory and Computer Program for Processing the Meaning Content of Natural Language Utterances. Stanford, Calif.: Stanford Artificial Intelligence Laboratory. Memo AIM-233.        Schank, R. (1975). Conceptual Information Processing. New York: Elsevier.        Schank, R., Lebowitz, M., & Birnbaum, L. (1980). An integrated understander. American journal of Computational Linguistics, 6(1).        Searle, J. (1969). Speech Acts: An Essay in the Philosophy of Language. Cambridge: Cambridge University Press.        Sperber, D. & Wilson, D. (1986). Relevance: Communication and Cognition. Cambridge, Mass.: Harvard University Press.
The above are also incorporated by reference herein.

System and method for natural language processing of query answers


A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

Memory devices are used to store information in digital form in computers and in many other types of devices in use today. Conventional memory devices may be classed as being volatile or nonvolatile. In a volatile memory device, logic state information can be stored only as long as electrical power is supplied to the volatile memory device, and is erased once the electrical power is turned off. In a nonvolatile memory device, the logic state information can be retained for months or years after the electrical power has been turned off.
The present invention is of a microelectromechanical memory apparatus that allows logic state information to be sequentially entered therein, and subsequently read out in the same sequence in which the information was entered into the device. Thus, the microelectromechanical memory apparatus of the present invention can be referred to as a first-in-first-out (FIFO) memory, or as a micromechanical memory, or simply as a mechanical memory. The mechanical memory of the present invention in different embodiments can be formed as a volatile memory or as a nonvolatile memory.


The subject invention relates to compositions comprising an enzyme mixture which comprises a first enzyme and a second enzyme, where the first enzyme comprises a DNA polymerization activity and the second enzyme comprises an 5′-3′ exonuclease activity and a reduced DNA polymerization activity. The invention also relates to the above compositions in kit format and methods for high fidelity DNA synthesis using the subject compositions of the invention.

DNA polymerases catalyze the synthesis of DNA and can be found in all cells as well as being encoded in numerous viruses. Although all DNA polymerases possess 5′-3′ DNA polymerization activity, DNA polymerases differ from one another in numerous other properties. For example, some enzymatic activities that are possessed by some DNA polymerases, but absent in other DNA polymerases include: double stranded DNA 5′-3′ exonuclease activity, single-stranded DNA 3′-5′ exonuclease activity, double-stranded 3′-5′ DNA exonuclease activity, RNase H activity, reverse transcriptase activity, and the like. Additionally, different DNA polymerases may have different optimal pH and temperature ranges for activity. Furthermore, DNA polymerases may differ in the rate in which they catalyze DNA synthesis.
Purified DNA polymerases have numerous uses in vitro. A detailed description of DNA polymerases, including methods for their isolation, can be found among other places, in DNA Replication 2nd edition, by Kornberg and Baker, W. H. Freeman & Company, New York, N.Y. 1991. In vitro uses of DNA polymerases include, for example, the labeling and synthesis of hybridization probes, DNA sequencing, and DNA amplification. A DNA amplification method employing DNA polymerases that has been particularly useful is the polymerase chain reaction (PCR) technique which employs the use of a thermostable DNA polymerase.
The first thermostable DNA polymerase that is widely used for DNA amplification is Taq DNA polymerase isolated from the thermostable, aerobic bacterium Thermus aquaticus. Taq DNA polymerase's enzymatic activity at high temperatures allows for primer extension and sequencing of polynucleotide templates with complex secondary structures (i.e., by PCR amplification). However, Taq DNA polymerase has significant error rate when incorporating nucleotides due to the lack of 3′-5′ exonuclease activity (i.e., proofreading activity), and therefore may not be suitable if the amplified sequence is to be used in further gene structural/functional studies or cloning.
In the last 10 years, numerous studies have quantified the error rate of thermostable DNA polymerases, and several enzymes have been found to copy DNA more accurately than Taq DNA polymerase (referred to as high fidelity DNA polymerases). U.S. Patent describing DNA polymerases include U.S. Pat. Nos. 4,492,130; 4,946,786; 5,210,036; 5,420,029; 5,489,523; 5,506,137; 5,545,552; 5,618,711; 5,624,833; 6,238,905; 6,100,078; 6,077,664; 5,968,799; 5,948,663; 5,885,713; 5,834,285; 5,756,334; 5,747,298; 5,744,312; 5,624,833; 5,602,011; 5,556,772.
High fidelity polymerases alone should definitely increase fidelity rates but usually do not amplify long fragments as efficient as a DNA polymerase lacking a 3′-5′ exonuclease activity (e.g., Taq DNA polymerase). Enzyme mixtures that combine a standard polymerase with a small amount of proofreading polymerase may provide a balance between fidelity and yield. A study published in 1994 illustrated that the use of a high level of a DNA polymerase lacking 3′-5′ exonuclease activity (an exo− DNA polymerase, Klentaq-1) with a very low level of a thermostable DNA polymerase exhibiting 3′-5′ exonuclease activity (an exo+ DNA polymerase such as Pfu, Vent, or Deep Vent) generated products with increased base-pair fidelity with a maximum yield of 35 kb DNA from 1 ng of lambda DNA template (Barnes, Proceedings of the National Academy of Sciences, 91:2216-20, 1994). Similarly, U.S. Pat. Nos. 5,436,149 and 6,008,025 disclosed methods for improving DNA amplification fidelity using a DNA polymerase composition comprising a first enzyme substantially lacking 3′-5′ exonuclease activity and a second enzyme comprising 3′-5′ exonuclease activity. In mixtures such as these, the exo+ enzyme acts to correct polymerization errors produced by the exo− DNA polymerase.
The problem inherited in the above composition comprising the mix of two DNA polymerase is that the high polymerization activity resulted from combining the two DNA polymerases may inhibit the efficiency and therefore the yield of the amplification reaction. It is also known that the amplification fidelity may also be affected by high DNA polymerase concentration (see for example, Mattila et al., 1991, Polynucleotides Research, 19:4967-73).
There is therefore a need in the art for new methods and compositions which improve polymerization fidelity and reduce the side effects resulted from having high polymerization activity in the reaction.

This patent is subject to a terminal disclaimer.

High fidelity DNA polymerase compositions and uses thereof


A process for producing an electrically conductive organic polymer, which comprises subjecting an organic polymer having an imino-p-phenylene structural unit represented by the following formula ##STR1## as the main repeating unit to a doping treatment with a solution having dissolved therein a quinone series oxidizing agent together with a protonic acid.

In general, an electrically conductive organic polymer called polyaniline is a polymer having a quinonediimine structural unit represented by the following formula as the main repeating unit ##STR2## and which contains a dopant (U.S. Pat. No. 4,615,829). In more detail, the electrically conductive organic polymer is a quinonediimine.phenylenediamine type polyaniline having a quinonediimine structural unit and a phenylenediamine structural unit represented by the following formula as the main repeating units ##STR3## and which is doped with a protonic acid.
It is generally said that protonation of nitrogen atom in the quinonediimine structural unit in such a polyaniline is indispensable to exhibit the electrical conductivity.
In the above formula, m and n show molar fractions of the quinonediimine structural unit and the phenylenediamine structural unit," respectively, in the repeating unit, provided that 0<m<1, 0<n <1, and m+n=1.
A film comprising the electrically conductive polyaniline can be obtained by dissolving a solvent-soluble quinonediimine-phenylenediamine type polyaniline in a proper solvent, casting the solution followed by drying to form a film, and subjecting the film to a doping treatment (protonic acid doping) by immersing the film in an aqueous solution of a protonic acid as described in, e.g., JP-A-3-28229 (corresponding to U.S. patent application Ser. No. 07/413,502) (the term "JP-A" as used herein means an "unexamined published Japanese patent application").
Further, JP-A-3-52929 describes that an electrically conductive polyaniline film is obtained by dissolving an imino-p-phenylene type polyaniline having an imino-p-phenylene structural unit shown by the formula ##STR4## as the main repeating unit in a solvent, adding thereto a proper oxidizing agent, and casting the mixture to form the film. According to this process, the imino-p-phenylene type polyaniline is oxidized and converted into a quinonediimine-phenylenediamine type polyaniline. In this case, the polyaniline is also doped with the anion of the oxidizing agent. Since doping in this case is accompanied by an oxidation reaction, the doping is usually called oxidation doping.
As described above, in order that a polyaniline has an electrical conductivity, it is necessary that the polyaniline has both the quinonediimine structure and the phenylenediamine structure in the molecule and also it is necessary that the nitrogen in the quinonediimine structure is protonated (doped). However, hitherto, for doping with the protonic acid as above, a long time is usually required. The doping time differs according to the kind of the protonic acid used and the properties of the polyaniline film, such as the film thickness, porosity, etc., and in the polyaniline film having a thickness of about 20 .mu.m, for imparting an electrical conductivity of at least 1 S/cm, it is required to immerse the film in an aqueous hydrochloric acid solution for several hours. When p-toluenesulfonic acid is used as the acid, several days are sometimes required. Requirement of such a long time for doping is disadvantageous for the industrial production of an electrically conductive polyaniline film.
On the other hand, it is described in JP-A-60-133027 and Faraday Discuss. Chem Soc., 88, 317(1989) that a quinonediimine-phenylenediamine type polyaniline can be obtained by subjecting the powder of an imino-p-phenylene type polyaniline to an oxidation doping treatment with an acetonitrile solution of ferric chloride or with hydrogen peroxide and a solution of an inorganic acid such as hydrochloric acid, sulfuric acid, phosphoric acid, etc.
Accordingly, oxidation doping can be also carried out by a process of first forming an imino-p-phenylene type polyaniline film by casting an imino-p-phenylene type polyaniline solution and then immersing the film in an aqueous solution of an oxidizing agent such as ferric chloride, etc., in place of the above-described process of forming the film after adding the oxidizing agent to the polyaniline solution. The oxidation doping is different from protonic acid doping in the point that an oxidation reaction is accompanied
In general, oxidation doping has an advantage that the required time may be short as compared with protonic acid doping but on the other hand, since, for example, when an oxidizing agent such as ferric chloride is used, hydrogen chloride is a dopant and when a combination of hydrogen peroxide and methanesulfonic acid is used, methanesulfonic acid is a dopant, there is a problem in the stability of the electrical conductivity after doping the polyaniline film. Further, when hydrogen peroxide is used as an oxidizing agent, there is the problem in that the mechanical strength of the polyaniline film is decreased by the doping treatment.

Process for producing electrically conductive organic polymer


A digital sound broadcasting receiver and method receives a radio wave from a digital sound broadcasting station, demodulates the radio wave into baseband signals at a tuner, subjects the signals to demodulation, performs error detection and error correction at signal processors to obtain digital data, and inputs the digital data into an audio circuit to obtain audio or data output. A CRC error rate detector 13 for a fast information channel (FIC) for APC pseudo lock releasing action on demodulating the signals is arranged to determine, based on the possibility of an error rate of an error-detecting code (CRC) of the FIC, whether an APC pseudo lock state occurs, and to control releasing action for the APC pseudo lock state.

Field of the Invention
The present invention relates to a digital sound broadcasting receiver which corresponds to an orthogonal frequency division multiplex modulation (hereinbelow, referred to as "OFDM") digital broadcasting system with respective carriers phase modulated wherein a synchronizing signal, which have a predetermined modulation, is transmitted in a frame.

Digital sound broadcasting receiver and automatic phase controlling method therefor


One or more systems, devices, and/or methods for generating a map including path side data include storing path side data referenced to three-dimensional geographic coordinates. The path side data may be optical data or optical data modified based on one or more panoramic images. The path side data is combined with map data received from a map database. The map data includes nodes and segments. A processor rotates the path side data based on one of the segments. The rotation may be about the segment or about a featured identified in the optical data. The path side data overlaid on the map data is outputted to a display, a file, or another device.

The present invention relates to maps and navigation and, more particularly, to method(s) and system(s) for overlay path side imagery on a map.
Conventional map applications include graphical representations of roads as well as icons corresponding to points of interest. The map applications may calculate and display a route from an origin point to a destination point. The route may be selectable between driving, walking, public transportation, and biking.
Some map applications illustrate a view from the perspective of a roadway through the manipulation of image bubbles. Image bubbles are panoramic images collected with respect to a single perspective. The image bubbles may extend nearly 360 degrees along one or more axes. Zooming and panning within an image bubble provides a view from a particular viewpoint. To view another perspective, a typical street level viewing application must be switched to the next image bubble. That is, in order to view the scene along the side of the street, a user must select a direction to move to the next image bubble and wait for the next image bubble to load, which may also require a panning operation.


The present invention relates to biocatalysts that are cells, optimally of the Crabtree-negative phenotype, comprising expression vectors encoding genes heterologous to the cell that enable increased production of organic products. More specifically, the invention relates to genetically modified Candida cells, methods for making the Candida cells, and their use in production of organic products, particularly lactic acid.

The use of microorganisms for synthesizing industrially important organic products is well known. Biosynthetic approaches for producing organic products can be extremely efficient when compared to large-scale chemical synthesis. Advantages a biosynthetic approach may have over a chemical synthetic approach for manufacturing an organic product include more rapid and more efficient product yield, isomeric purity, and reduced cost (see Thomas et al., 2002, Trends Biotechnol. 20: 238–42).
Lactic acid has wide industrial applicability, including uses in chemical processing and synthesis, cosmetics, pharmaceuticals, plastics, and food production. Lactic acid is a relatively simple organic molecule, and can be produced either by chemical synthesis or by fermentation in microorganisms (biosynthesis). As genetic manipulation of microorganisms has become more advanced, fermentation processes for lactic acid production have become commercially preferred over chemical synthesis. One reason for this preference is that using genetically modified microorganisms enables production of optically pure (i.e., either the L(+) or D(−) isomer) product. Such methods obviate the need for separating racemic product mixtures, thereby reducing cost.
Nevertheless, the use of microorganisms for producing organic products has certain limitations. For example, bacteria can produce large quantities of organic products under fermentation conditions, but the accumulation of organic products within the bacteria itself and in the growth medium can inhibit proliferation of the bacteria, or cause cell death. Even when more robust organisms are engineered and used for production, such as the acidophilic yeast Saccharomyces cerevisiae, organic products can lead to cell growth suppression, reducing overall yield of organic product. Thus, there remains a need in the art for robust microorganisms that are amenable to genetic manipulation, for use in bioreactors and with other biosynthetic methods for producing industrially important organic products.

Methods and materials for the production of organic products in cells of


A medical electrical lead having an elongated conductor including one or more wires made of a modified MP35N alloy. The modified MP35N alloy is formed from a melt composition modified to reduce an amount of titanium-based inclusion forming elements.

Early cardiac pacemaker conductors were composed of numerous fine, stranded stainless steel wires. Marked improvement in both fracture rate and flexibility resulted when stainless steel conductors were wound into small coils with a hollow core. The hollow core of the coils also improved implantation since a stylet could be passed through the core during implantation to stiffen the lead. Corrosion resistance was significantly increased when stainless steel was replaced with more corrosion-resistant platinum iridium and nickel alloys such as Co—Ni—Cr—Mo alloy, available commercially as MP35N®, from Standard Pressed Steel Co., Jenkinstown, Pa. Highly specialized conductors were formed from such alloys such as multifilar coiled conductors and drawn, brazed strand wire. The use of multiple filars avoids the loss of electrical continuity in the event that one filar breaks. Drawn, brazed strand wire provides a low electrical resistance in a wire with high fatigue strength. Multifilar coils can also be used in side-by side or coaxial arrangements with insulation separating the conductors to provide individual conductors for the transmission of separate signals or stimulation pulses.
One limitation of commercially available alloys suitable for medical lead conductors, such as MP35N or Co—Cr—Ni—Fe—Mo—Mn alloy (known as Elgiloy®, from Elgiloy, Ltd.), is that foreign inclusions of nitride, oxide and/or carbide bodies present in the alloy negatively influence the metal fatigue life. Inclusions differ in mechanical and physical properties from the bulk alloy matrix. Titanium (Ti) is deliberately added to the MP35N alloy melt and is a significant carbide/nitride former. The inventors of the present invention have found titanium-nitride inclusions at or near fracture initiation sites of MP35N alloy wires that were rotary beam fatigue tested. Specifically, relatively hard, cubic titanium-carbide and titanium-nitride inclusions in excess of one micron in cross-section located within approximately three microns of the wire surface have been found to promote fatigue crack initiation in cold drawn wires having diameters between approximately 0.005 and approximately 0.010 inches in diameter.
The formation of oxide, carbide and nitride inclusions is related to melt practices employed in producing an alloy and casting it into ingot forms. Elgiloy develops oxide-based inclusions during vacuum induction melting and secondary melting during electro-slag refining, which occur under ambient atmospheric conditions allowing light metal oxides to reach equilibrium conditions. Sub- to multi-micron diameter oxide inclusions result. Formation of titanium-based inclusions in MP35N is a process not fully understood but is expected to be related to pressure, temperature, elemental concentrations, and other equilibrium-driving factors present during alloy melt practices.
As patient indications for cardiac pacing expands, new pacing systems are being developed, such as multi-chamber or biventricular pacing systems, that require the use of relatively small diameter leads. These systems can use multiple leads, and multiple electrodes may be carried on a single lead requiring multiple conductors. In order to implant multiple leads through a venous access point, or advance a single lead through a narrow, tortuous pathway such as the cardiac veins, very small diameter leads are desired. Leads are presently being manufactured having a diameter on the order of 2 to 4 French. In order to manufacture such small diameter leads, conductor wires must be drawn very fine, on the order of 0.001 inch or less. As conductor diameter is reduced, the impact of inclusions on fracture resistance becomes greater. It is desirable, therefore, to provide a corrosive-resistant conductor having low electrical resistance that has improved fatigue resistance due minimization of the number and/or size of foreign inclusions.

Medical electrical lead conductor formed from modified MP35N alloy


A blade cleaning jig includes a cleaning portion and a gripping portion. The cleaning portion includes a support body of stainless steel or the like and polishing tape provided on the upper face of this support body, and moreover a cushioning material is inserted between the support body and the polishing tape. A protective member for preventing damage to the surface of a developer roller is attached to the entire lower face of the support body. This protective member is attached bent at a circumferential end portion such that the protective member covers from the lower face of the support body via a circumferential edge portion to an upper face circumferential edge portion.

This application claims priority under 35 U.S.C. §119(a) on Japanese Patent Application No. 2005-330659 filed in Japan on Nov. 15, 2005, the entire contents of which are hereby incorporated by reference.
The present technology relates to a blade cleaning jig that is applied in an image forming apparatus such as a copier, printer, or facsimile machine that forms an image by electrophotography. More specifically, the present technology relates to a blade cleaning jig that is effective for removal of toner that is affixed to a toner layer control blade, in a development apparatus in which a non-magnetic one-component developer is used.
In general, in a non-magnetic one-component developing method, regardless of whether the toner is magnetic or non-magnetic, a thin layer of one-component toner that has been charged is formed on a developer support, and with rotation of a developer roller, this thin layer is conveyed to a developing position that faces a photosensitive drum on which a latent image has been formed, and thus the latent image on the photosensitive drum is developed. In this case, the question of how to stably form a thin toner layer with uniform layer thickness and uniform charging on the developer roller is important for obtaining a good image.
In general, charging of the toner layer on this developer roller and thin layer formation are performed by a toner layer control blade that has been pressed against the developer roller with a predetermined pressure. In this toner layer charging and thin layer formation, there are cases in which toner becomes firmly adhered to the toner layer control blade due to use for a long period, so a good toner layer cannot be formed, which leads to image degradation. That is, the toner layer control blade continues to make contact with the developer roller with a predetermined pressure, and due to environmental factors or the like such as frictional heat, that pressure, or internal temperature of the apparatus, in the region where the toner layer control blade makes contact with the developer roller and the vicinity thereof, toner adheres (affixes) to the blade surface.
This affixed material, at first, is only slightly present like a thin film that has been spread on the surface, in an amount that is not particularly a problem even for image formation, but it grows with accumulated usage, and eventually has an adverse effect on images.
That is, the chargeability of the toner is worsened by the toner layer control blade due to the affixed material, and the affixed material plugs a toner inflow port between the developer roller and the toner layer control blade, or alternatively forms mechanically uneven portions in the surface that makes contact with the developer roller, leading to a decrease in toner layer thickness locally or as a whole, or local slippage (an increase in layer thickness), and it becomes impossible to form a uniform toner layer. As a result, a decrease in the density in the image, partial white streaks, or partial black streaks (in the case of a monochrome image) and the like occur.
Accordingly, in order to address these problems, development apparatuses have been proposed that clean toner affixed material on the toner layer control blade (for example, see JP S57-93370A).
The development apparatus disclosed in JP S57-93370A has a configuration in which a slidable cleaning member is provided between the developer roller and the toner layer control blade, and affixed toner is removed by sliding this cleaning member. That is, the cleaning member is configured with a thin plate member, where the front end of the cleaning member is extended to the top of the toner layer control blade, and at the rear end of the cleaning member, a tab is installed with the rear end extended outside from a groove provided in a developer container side wall. Also, the cleaning member is slidably supported and guided in the widthwise direction of the developer roller by copper wiring that has been stretched in the developer container in the center portion of the cleaning member. When foreign matter has become lodged between the toner layer control blade and the developer roller, by grasping the tab and sliding the cleaning member in the widthwise direction of the developer roller, the foreign matter is removed by the end of the cleaning member.
With the development apparatus disclosed in above JP S57-93370A, it is necessary to insure space to dispose the cleaning member inside the developer container. Also, because it is necessary to adopt a slidable structure for the cleaning member by stretching copper wiring in the development container or the like, there are the problems that the number of components increases, and the structure of the development apparatus becomes more complicated. Further, because the cleaning member is separately installed in the development apparatus, there is the problem that it cannot be applied in an existing development apparatus that does not have such a cleaning member.


Provided is a method for transmitting channel state information (CSI) by a terminal in a wireless communication system. The method sets a group including a plurality of cells, receives parameters for CSI transmission timings for the plurality of cells, and determines the CSI transmission timings for the plurality of cells on the basis of the parameters. The CSI transmission timings for at least two cells from among the plurality of cells are aligned to be the same.

Field of the Invention
The present invention relates to wireless communication and, more particularly, to an apparatus and method for transmitting channel state information in a wireless communication system.
Related Art
One of the most important requirements of a next-generation wireless communication system is to be capable of supporting a high data transfer rate. To this end, various techniques, such as Multiple Input Multiple Output (MIMO), Cooperative Multiple Point (CoMP) transmission, and a relay, are being researched, but the most basic and stable solution is to increase a bandwidth.
Frequency resources are now in the saturation state, and various techniques are partially being used in a wide range of frequency bands. For this reason, as a scheme for securing a wide bandwidth in order to satisfy a need for a higher data transfer rate, a Carrier Aggregation (CA), that is, a concept in which each of scattered bands is designed to satisfy a basic requirement in which each band can operate as an independent system and a number of bands are aggregated into a single system, is being introduced. In this case, a band or carrier that is capable of independently operating is defined as a Component Carrier (CC).
In a recent communication standard, for example, in a standard, such as 3rd Generation Partnership Project (3GPP) Long Term Evolution-Advanced (LTE-A) or 802.16m, to extent a bandwidth up to a 20 MHz or more is being taken into consideration. In this case, a wideband is supported by aggregating one or more CCs. For example, if a single CC corresponds to a bandwidth of 5 MHz, a maximum bandwidth of 20 MHz is supported by aggregating 4 carriers. A system supporting a CA as described above is called a CA system.
Meanwhile, a wireless communication system controls a Modulation and Coding Scheme (MCS) and transmission power depending on a given channel using link adaptation in order to utilize a given channel capacity to a maximum degree. In order for a base station to perform such link adaptation, a terminal needs to feed channel state information back.
In accordance with a conventional technology, when a collision in which pieces of periodic channel state information about a plurality of carriers are configured in a CA system so that they are transmitted in a specific subframe at the same time is generated, only the periodic channel state information of a single carrier that is determined according to priority is transmitted.
If pieces of periodic channel state information about a plurality of carriers collide against each other in the same subframe, all the pieces of periodic channel state information may need to be transmitted. In such a case, there is a problem in that the transmission time point of periodic channel state information about each of the carriers will be configured using what scheme.

Method and apparatus for transmitting channel state information in wireless communication system


A microwave applicator chamber to effectively sterilize animal waste having a series of rotating chamber sectors carrying the waste under a source of intense radio frequency energy. The animal waste emerges free of pathogens and odor causing bacteria, ready for incorporation into plant fertilizers.

The ample production of beef, pork, chicken and dairy products in large scale, centralized animal production facilities to meet the growing demand for a high protein diet in our wealthy society have been accomplished with increasing economy. High quality meat and milk products are delivered to the grocer's shelves at bargain prices. Unfortunately, the byproduct of centralized animal husbandry are ever growing open pits or lagoons of untreated, semi-liquid animal wastes.
Recent concerns over the possibility of pathogens in these animal wastes leaking into lakes and rivers or entering the underground water supply have provoked civic actions. intestinal parasites, such as giardia and cryptosporidium and pathogenic viruses and bacteria, which can infect man, are capable of entering the watershed from theme animal waste ponds. If these plant nutrient containing byproducts enter our lakes and rivers, the normal ecology is overwhelmed by "blooms" of algae which use up all the dissolved oxygen, killing fish and other aquatic creatures. These animal manures, if properly treated and applied, become useful plant fertilizers and complete the nutrient cycle if returned to the land for crop production.
The present invention proposes to treat animal wastes with intense radio frequency energy to destroy all pathogens. Semi-liquid manures are pumped into a specialized multimode, resonant chamber with a series of moving partitions, each of which moves animal waste products in sectors into the path of the radio frequency energy for sterilization.
For portable, on-site treatment of existing animal waste lagoons, all necessary equipment is brought to the site and operated from a trailer mounted, self contained system. The complete system has a portable electricity generator, a portable radio frequency energy generator, semi-liquid animal waste handling pumps with flexible piping, the [RF] radio frequency energy applicator assembly and treated animal waste retaining and bagging equipment. Stationary and permanent installations can be added to the final stage, waste treatment procedures at existing dairies, farms and feedlots.
Exiting treated wastes can be mixed with moisture adsorbing materials and fortified with additional nutrients and trace minerals to produce rich fertilizer pellets. the pellets can be bagged for storage or shipped for immediate use.
Description of the Prior Art
Kishi (U.S. Pat. No. 5,152,074) proposes a drying apparatus having a casing provided with stirring blades and heating bodies therein (col. 1 lines 65-68) in which the raw sewage is stirred by the rotation of the stirring blades and heated by the heat generated by the heating bodies.
There are significant differences between Kishi and applicant. Although Kishi lists several continuing applications, those available to applicant at this writing all seem to be based upon the use of microwave or magnetic flux to heat ceramic or metallic balls 29, and to completely dry the raw sewage to a sterile ash for ease of disposal. Kishi describes a portable toilet. He claims a raw sewage drying apparatus comprising a casing, a rotating drive shaft unit having a plurality of blades for stirring the raw sewage, and bodies or ball elements capable of being heated by directing electromagnetic waves toward the casing. The ball elements are made from a radio frequency energy adsorbing material and transfer enough heat to the surrounding sewage to dry and pulverize to a powdery ash for vacuum collection in a dust collector. In applicant's invention the need for ball elements are unnecessary. The radio frequency energy heats the waste directly, because of the high dielectric absorption of the water contained within the waste. Applicant's rotating partition walls simply move accumulated waste in sectors under the radio frequency energy window for exposure to intense radio frequency energy.
The objectives of applicant are to directly heat the pathogens in the manure and to prepare a material to serve as a base for a fertilizer.
Simon (U.S. Pat. No. 3,997,388) claims a method and apparatus to dry manure with microwave radiation at the preferred frequency of 2450 Maz in combination with ultrasonic energy to accelerate evaporation and discourage matter from adhering to the surfaces.
Applicant relies upon slick vertical, polymer surfaces and wiping action to discourage adhesion of semi-liquid wastes. The ultrasonic energy introduced by Simon is unnecessary in the applicant's invention.

Radio frequency animal waste treatment apparatus


A television signal distribution network includes respective distributor cables for signals from respective satellite antennas, one of such cables also being coupled to a terrestrial signal source and serving as a dual distribution cable for both satellite and terrestrial signals. A switching unit permits each user terminal to be selectively connected to any of the distributor cables for reception of a selected satellite signal. The user terminals are also all coupled to the dual cable via a filter which only passes the terrestrial signal band, whereby the terrestrial signal is distributed to all terminals from only a single cable, independently of the setting of the switching unit. Another of the distributor cables also serves as a return cable for upstream signals from the user terminals. The return path includes a filter which only passes an upstream frequency band below that of the terrestrial and satellite signals.

1. Field of the Invention
The invention relates to a television signal cable distribution network comprising a plurality of distributor cables conveying a plurality of satellite signals which are possibly different from cable to cable, a service device for supplying signals to a user terminal, tapping units for tapping each cable for signals from such cable, and a switch for connection of the user terminal to a selected one of the tapping units.
The invention also relates to the aforesaid service device of such a television signal cable distribution network.
2. Description of the Related Art
A television signal cable distribution network of the type described in the opening paragraph is known from U.S. Pat. No. 5,382,971 issued Jan. 17, 1995 to the present inventor and assigned to the present assignee. In the network described in this document, the signals received from terrestrial stations are added in each cable to the signals received via satellite. This is an ingenious way of enabling each user to receive the terrestrial channels without being obliged to choose a particular cable from among the plurality of cables, but it has the drawback that the cables are heavily loaded, which reduces the possibilities of the system and, inter alia, increases intermodulation in amplifiers.

Television signal cable distribution installation


A semiconductor device has a SALICIDE structure with low leakage currents, while maintaining shallow source and drain regions. A method of manufacturing the semiconductor device includes forming source and drain regions in a first semiconductor layer, the source region and the drain region being separated from each other, forming a gate insulating film between the source region and the drain region on the first semiconductor layer, and forming a gate electrode on the gate insulating film. The method also includes forming a metal silicide layer showing a first compound phase on the source region, the drain region and the gate electrode, and forming a second semiconductor layer on the metal silicide layer showing the first compound phase where the second semiconductor layer is adapted to react with the metal silicide layer. The method further includes forming a metal silicide layer showing a second compound phase by causing the second semiconductor layer and the metal silicide layer showing the first compound phase to selectively react with each other.

1. Field of the Invention
This invention relates to a method of manufacturing a semiconductor device and also to a semiconductor device.
2. Description of the Related Art
The demand for miniaturization of individual semiconductor devices and large-scale integration of such devices has been and still is increasing to realize high-speed operation and also to attain versatile functionality of semiconductor circuits. However, for successful shrinkage of the device dimensions, various related difficulties are to be overcome. Such difficulties will be understood when considering miniaturization of a MOSFET which comprises an integral part of a semiconductor circuit.
For instance, with reduction of a channel length (i.e., length of the gate electrode) of the MOSFET, its threshold voltage decreases (i.e., short channel effect). If the threshold voltage decreases from an intended value, the MOSFET will operate in an unexpected way and may impair the entire function of the circuit. Moreover, the extent of the voltage drop depends sharply on the physical length of the gate electrode. It entails that, for fabrication of small dimension MOSFET's, a minor variation of the gate length originated from a process fluctuation of gate electrode formation will result in a large deviation of the threshold voltage. This short channel effect becomes especially problematic when a circuit requires a large number of MOSFET's with an identical function (such as dynamic random memories, DRAM). The strict requirements for the functional uniformity of the individual device can be satisfied only through an extremely tight quality control of the manufacturing processes, thus restricting the manufacturability of integrated circuits such as DRAMs.
The short channel effect is caused when distortion of electric field in the vicinity of the source and drain electrodes comes to influence the electric field around the center of the channel with the reduction of the channel length. The influence can be avoided by bringing the pn junction formed by the source and the drain closer to the semiconductor surface (i.e., by making the source and drain shallower). However, when the source and drain are simply made shallow, the electric resistance of the source and electrodes increases and obstructs high speed transmission of signals through the device.
To counter this problem, it is a common practice that upper portions of the source and drain regions are chemically combined with a metal to produce a compound (silicidation) which shows significantly lower resistivity than silicon. Metals that can be used for silicidation include Co, Ti and Ni, of which Co is most suitable. This is because it does not show any rise in the electric resistance when it is formed on thin lines (i.e., lack of narrow line effects) and is stable at high temperature. These preferable characteristics of the Co silicidation stand LSI fabrication in good stead.
However, during the silicidation reaction, metal atoms quickly diffuse into the silicon substrate and eventually penetrate the junctions forming the source and drain electrodes if the source and drain are made shallow. When the metal atoms migrate beyond the junctions of the source and drain, they generate leakage currents through the junctions. And source and drain electrodes stop functioning properly.
In fact, the metal atoms diffuse very quickly. In the case of Co, the Co atoms reach a depth of 150 nm even during the silicidation process at 800° C. for 30 seconds. FIG. 6 shows leakage levels of n+/p junctions with 35 nm-thick CoSi2 layer thereon as a function of the junction depth (the depth includes the 35 nm of the silicide layer thickness). For reference, leakage levels of silicide-less junctions are also plotted. From FIG. 6, a sizable increase of the leakage current is already evidenced at the depth of 150 nm from the surface, which is by far deeper than the bottom of the silicide film. The increase is due to a rapid migration of the Co atoms into the silicon substrate. In general, rapid diffusion of metal atoms proceeds inevitably along the interfaces between metal and silicon during the silicidation reaction. The metal atoms that have penetrated deep into the silicon substrate form generation-recombination centers in the band gap of silicon and mediate junction leakage currents. If such gap states are formed in the source/drain junctions, leak currents flow through the source/drain electrodes towards the silicon substrate. Then, the function of the MOSFET is impaired. When the MOSFET constitutes a part of a DRAM's memory cell, the data stored in the cell will be lost and the semiconductor circuit will no longer operate properly.
To alleviate this problem, a technique (known as elevated source/drain method) for selective formation of additional silicon layers on the source and drain regions are developed. With this technique, the surfaces of the semiconductor substrate, where the source and drain electrodes are to be formed, are raised above the original semiconductor surface (where the channel is formed). Then, over the additionally elevated surfaces, pn junction formation for the source and drain regions and the silicidation process are performed. The junctions formed in this way can be located at a shallow position relative to the original surface of the semiconductor substrate, while maintaining a deep position as viewed from the newly elevated surfaces of source and drain regions. Hence, a sufficient thickness of the source/drain electrodes can be secured.
Such a selective elevation of source and drain surfaces can be realized by using a technique known as selective epitaxial growth. However, for this technique to be successfully applied to actual device fabrication, the final position of the resulting pn junction of the source/drain regions needs to be precisely positioned at the original semiconductor surface (where the channel is formed) or be located slightly below it. This is because drivability of the MOSFET is remarkably reduced if the junction is located above the original surface (the channel interface), whereas a severe short channel effect appears if the junctions are located far below the original surface.
However, the epitaxial growth is very sensitive to the state of the substrate surface on which the selective silicon growth is to be achieved. For instance, the thickness of the silicon film grown on the substrate varies depending on the roughness or crystalline structure of the substrate surface. Also, the quality of the grown film (i.e., the presence/absence of the crystalline defects in the film) depends on the surface condition of the substrate. Thus, for example, incomplete removal of a native oxide on the substrate surface or residual process-damage incurred during gate electrode formation may well result in severe variation in the film thickness between individual devices for which elevation of source and drain regions is attempted.
If the thickness of the additionally formed silicon films is not uniform, it is very difficult to place pn junctions of source/drain regions near the original surface of the semiconductor substrate (where the channel is formed) in a controlled manner. Impurities for the source/drain formation are introduced through the surfaces of the additionally formed silicon films. Non-uniform thickness of the additionally formed silicon films makes the relative distances from their surfaces to the original semiconductor surface (i.e., channel surface) indefinite. Thus, the junctions cannot be accurately placed at the original semiconductor surface whose location is indefinite relative to the surfaces from where the impurities are introduced.
Likewise, if the quality of the grown silicon films differs from a device to a device, it becomes difficult to place the pn junctions precisely at the targeted position near the original semiconductor surface. This is because, the presence of crystal defects in the film (i.e., the film quality) greatly influences the speed of impurity diffusion in the film (e.g., transient enhanced diffusion). It entails that a predetermined thermal diffusion of the impurity for the junction formation could result in non-uniform junction depth due to unexpected impurity diffusion caused by the crystal defects in the film.
Similarly, the diffusion of metal atoms during silicidation is also subject to the quality of the grown silicon films. Thus, even when the source and drain regions are raised by the additional silicon films, if their thickness and quality are non-uniform, metal atoms can easily diffuse and penetrate the junctions at points where the film thickness is thin or the film quality is low. It follows that the non-uniformity of the film thickness and quality limits the effectiveness of the epitaxial growth to counter the leakage generation by the silicidation process.
Furthermore, the metal diffusion in a silicon crystal is very fast itself. Accordingly, in order to block the metal diffusion effectively, the additional silicon layer must be very thick (i.e., thicker than 150 nm). However, due to above-describe reasons, it is almost impossible to selectively and uniformly grow silicon layers as thick as 150 nm on the individual source and drain regions.
Moreover, the height of the source and drain regions, raised by 150 nm, almost equals the height of the gate electrodes. The lack of the height-difference makes it difficult to ensure electrical isolation between gate electrodes and source/drain regions when silicidation process is applied to these electrodes and regions simultaneously (SALICIDE (self-align-silicide) process).
In addition, a selectively grown silicon film tends to become thinner in a region adjacent to a gate electrode (which is an intrinsic characteristic of the epitaxial growth). Prior to the silicidation process, the shortest distance between a metal film deposited on the device surface and the source/drain junction is determined at this portion. Hence it is this thinner region that could eventually limit the film's ability to block the metal diffusion regardless of the thickness of the additional silicon films grown elsewhere.
As described above, in manufacturing of a small-dimension MOSFET device, a silicide layer must be formed on source and drain regions to secure low electrical resistance of the regions while keeping a shallow junction position of the source and drain regions. However, fast metal diffusion during the silicide reaction easily penetrates the shallow junctions and induces leakage. To counter the leakage generation, source and drain regions could be elevated by selective epitaxial growth. Even with this elevation, the fast metal diffusion requires that a silicon layer must be selectively grown to a thickness almost equal to the height of a gate electrode. Unfortunately, however, it is very difficult to form such a thick film having a uniform thickness and quality with this method.
Thus, it is the object of the present invention to provide a semiconductor device that has a SALICIDE structure with low leakage currents and a source/drain height lower than the gate electrode, while maintaining shallow source and drain regions, without the above identified problems of conventional methods. It is also the object of the present invention to provide a method of manufacturing such a semiconductor device.

Semiconductor device including forming an amorphous silicon layer over and reacting with a silicide layer


An asynchronous transfer mode adaptation layer switching network has independent call routing and connection control for setting up connections across the system. A plurality of adaptation layer switches (ALS) coupled to the ATM network comprise a group adapted to function as an adaptation layer switching network whose fabric and control are distributed over the group. The network having means for determining its current system status whereby to set up multimedia calls across the network based on that status determination.

This invention relates to digital communications systems and in particular to systems embodying asynchronous transfer mode (ATM) technology. The invention further relates to the application of PNNI (Private Network Network Interface) signalling to control an ATM adaptation layer switching network.
The asynchronous transfer mode (ATM) technology is a flexible form of transmission which allows any type of service traffic, voice, video or data, to be multiplexed together on to a common means of transmission. In order for this to be realised, the service traffic must first be adapted typically into 53 byte cells comprising 5 byte headers and 48 byte payloads such that the original traffic can be reconstituted at the far end of an ATM network. This form of adaptation is performed in the ATM adaptation layer (AAL).
A recent development has been the introduction of the AAL-2 adaptation layer. This adaptation layer has been optimised to accommodate the demands of low bit-rate communications representing the increasing trend to greater voice compression. The adaptation layer is a multiplex of users in a single ATM connection where each user""s information is carried in short packets or minicells each with a header identifying the user channel and incorporating ancillary control information. This constitutes a dynamic trunk group of users in a single connection.
As telecommunications networks increase in complexity and carry increasing volumes of traffic, the current procedures for setting up connections between subscribers are limiting the performance of these networks. In particular, congestion may be caused by attempting to connect to a subscriber who is already busy, or by attempting to choose a route through an already congested part of the network. Thus equipment and resources can be wasted in attempts to set up calls which cannot be completed. A further problem is that of scalability. As the network expands to accommodate increased traffic and a larger number of subscribers, there is an increasing need to facilitate integration of new equipment into an existing network without simply increasing the congestion problem. Moreover, careful planning is required to ensure that calls can be routed through the network. This requires an ad-hoc distributed routing decision policy which limits the flexibility of the routing process as the call routing must be collocated with the switching node fabric.
The object of the invention is to minimise or to overcome these disadvantages.
A further object of the invention is to provide an improved method of operating a telecommunications network.
According to one aspect of the present invention there is provided a asynchronous transfer mode adaptation layer switching network having independent call routing and connection control for setting up connections across the system.
According to another aspect of the present invention there is provided a distributed telecommunications exchange system having means for determining at a call source the current status of the system whereby to effect routing of a multimedia call across the system.
According to another aspect of the invention there is provided a method of communicating resource availability to maintain performance of an asynchronous transfer mode adaptation layer switching network under overload conditions.
According to a further aspect of the invention there is provided a method of routing telecommunications traffic in a system including an asynchronous transfer mode (ATM) network having uncommitted bandwidth, and a plurality of adaptation layer switches (ALS) coupled to the ATM network, which adaptation layer switches comprise a group adapted to function as an adaptation layer switching network whose fabric and control are distributed over the group, the method including determining the current system status whereby to set up multimedia calls across the network based on that status determination.
We have found that adaptation layer switching can be incorporated into an ATM private network network interface (PNNI) reference architecture to provide a mini channel connectivity layer and a routing architecture for establishing connections in the adaptation layer.
The arrangement and method facilitates both scalability of the network and the separation of call routing and connection control. The advantage of this separation of the two functions can be exploited by making routing decisions at the outset. Dynamic trunking allows the routing decisions to be independent of the connection control. With fixed trunk networks, voice routes are made up of small trunk groups that pertain to physical links which may be diversely connected. The status of these connections will affect the final route available. Because the status is distributed, so must be the routing, and hence there can then be no separation.
The arrangement and method further facilitate the simplification of the PNNI model to reduce hierarchy, obviate crank back and alternate path routing, and simplify call admission policy on a service related basis.
PNNI may be applied to dynamic trunking in the adaptation layer using ATM connections to represent the physical bearer, but additionally the virtual connectivity allows dual homing, load-balancing, diverse routing and virtual connections may be re-established automatically over alternative physical paths to maintain connectivity. This enables the construction of an extremely robust network.
Reference is here directed to our co-pending application No. GB-9614138.7. This application describes a telecommunications system comprising an asynchronous transfer mode (ATM) network having uncommitted bandwidth, and a plurality of adaptive grooming routers (AGR) coupled to the network. The AGRs comprise a group adapted to function as a virtual transit exchange whose fabric and control are distributed over the group. The virtual transit exchange comprising the AGRs incorporates independent connection control and call routing functions and has means for determining the current system status whereby to set up narrow band connections across the ATM network based on that status determination.


An emanation device is described which comprises: a replaceable refill of liquid containing one or more active materials wherein the active material comprises at least one of: a fragrance; an insecticide; a fungicide; a pesticide; a sanitizing material; and/or a pharmaceutical; wherein the refill comprises a sealed reservoir containing said volatile liquid and a porous wick which extends from the interior of the reservoir to the exterior thereof; and wherein the device comprises: an air pump; a fluid conduit in fluid communication with the air pump such that, in use, air pumped by the pump will flow through the fluid conduit; a nozzle located at the end of the fluid conduit remote from the air pump; a ejector constriction provided in the fluid conduit adjacent or substantially adjacent the nozzle; a liquid conduit provided adjacent the ejector constriction and in fluid communication with the fluid conduit at one end thereof, and open at the other end to receive liquid therein; characterized in that the liquid conduit is located within the porous wick.

Liquids, an particularly volatile liquids, containing one or more active materials wherein the active material comprises at least one of: a fragrance; an insecticide; a fungicide; a pesticide; a sanitising material; and/or a pharmaceutical are delivered within the domestic environment via a variety of mechanisms. Devices are available with heaters disposed therein to increase the rate of emanation from a surface saturated with the liquid, such a surface could be a wick saturated with a fragranced liquid and the heater is located adjacent the wick surface and nearby a chimney to heat the liquid on the wick surface and cause it to more readily evaporate and disseminate into the surrounding environment through the chimney.
Alternatively such liquids can be loaded in an aerosol canister, the canister holds the liquid under pressure and when the canister valve is opened the liquid is forced out. The liquid is provided with a propellant which evaporates inside the canister to maintain an even pressure and, outside the canister, assist with the mechanical break up of the liquid by evaporating rapidly. Suitable propellants include volatile hydrocarbons such as propane, butane or isobutane.
Aerosols generally provide a satisfactory spray performance but since they require manual operation by a user, they are not considered to be particularly convenient for routine use. Automatic aerosol activation devices exist for operation with metered dose aerosols. These devices are operable to periodically actuate the aerosol to cause a dose of the liquid to be sprayed.
Whilst the automation of the device overcomes the problem of manual operation of a canister, the use of aerosols containing such propellants is becoming increasingly less desirable since these volatile hydrocarbons carry the disadvantage of being flammable, the rising cost of oil is rendering them increasingly expensive and they also carry the further disadvantage of being an atmospheric source of carbon which is deemed to not be environmentally sensitive.
In the field of air freshening it is generally preferred to use a fragranced liquid/air freshening liquids comprising several components. These components often possess different volatilities which can lead to emission problems. The effect of fractionation can be particularly pronounced for powered emanation devices using a heater to effect emanation such as a plug-in emanation device or the like.
In such device a build-up phenomenon can occur in which an accumulation of volatile liquid components with the lowest comparative volatilities can occur leading to an undesirable non-uniform emanation profile for the liquid. This phenomenon can produce an olfactory sensation wherein the fragrance character changes over the course of emanation of a quantity of the fragranced volatile liquid such that the 'high notes' of a fragrance are the first to be evaporated when the wicking material is first exposed to the fragranced liquid, and the 'low notes' are evaporated thereafter.
Accordingly, it is an object of the present invention to provide a device that is capable of addressing the abovementioned performance drawbacks and other drawbacks that will be appreciated by a person skilled in the art.

Devices and methods for improved delivery of volatile liquids


A golf swing practicing article which is shorter in overall length than an ordinary golf club and substantially symmetrical around a center axis of a shaft body includes a grip member disposed at first end section of the shaft body and a weight member at an opposite second shaft body end section, the weight member increasing the mass at the said second end section, the weight member occupying 40 to 60% of said overall length. The weight member can have a tapered portion and a receiving portion for reception and removal of weights so as to vary the weight of the weight section, the weights being cylindrical members of different sizes and such that certain of same fit inside others of the weights.

1. Field of the Invention
The present invention relates to a golf swing practicing article which is shorter in overall length than an ordinary golf club.
2. Description of the Prior Art
In golf, one of the very effective techniques for driving the ball accurately is to swing the club in the so-called level swing style, which means to swing the club in such a manner that the golf player's shoulders and waist turn in given planes which are substantially perpendicular to a given swing axis.
However, it is by no means easy for ordinary golfers to practice this level swing in the swing of the golf club. The reason is that since the golf club has a head at the distal end of its shaft, the center of gravity deviates from the center axis of the shaft and grip of the club, causing the golfer to be conscious of the head which strikes the ball, said head deviating from the center axis of the shaft and grip. Therefore, in a swing practice using an ordinary club, realization of the level swing cannot be said to be easy.
Various swing practicing articles have heretofore been invented which are shorter in overall length than ordinary clubs to make it possible to practice even in narrow spaces. In such swing practicing articles, the mass in the distal portion is made greater than the mass of the ordinary club head in order to make the sensational weight in swing closer to that associated with the ordinary club. Such measure, however, results in excessive mass being concentrated in the distal portion only to cause the danger of the swing sensation obtained deviating from the ordinary swing sensation. Further, in that case, the shape of the distal portion is enlarged almost necessarily in accordance with the mass and hence the golfer takes the distal portion as the head, excessively concentrating his sensation on the distal portion, obstructing realization of the level swing.

4-28-203, Terauchi 1-chome, Toyonaka-shi


A fireplace comprises a firebox having a top panel, bottom panel, rear panel and a flue. An outer casing is spaced from and surrounds the firebox. A combustion air feed passage for supplying combustion air to the firebox is provided. A heat exchanger, which is located downstream from the flue for receiving the combustion gases and for transmitting the heat from the combustion gases to air to be heated, is also provided. The fireplace includes a passage for conveying the combustion gases from the flue to a conduit in communication with a source external to the room in which the fireplace is situated for exhausting the combustion gases from the fireplace and a switch for selectively coupling the heat exchanger in series with the passage. The switch is operable between a first position which the flue gases pass through the heat exchanger before being vented to the outside and a second position which the flue gases pass through the passage, bypassing the heat exchanger, and are then vented to the outside. A second passage is provided between the outer casing and the firebox for circulation of air to be heated along with the heat exchanger.

Various types of fireplaces are known in the art. One traditional type of fireplace is a masonry fireplace which is built into a room of a house or other dwelling unit. Such a fireplace has a masonry firebox and a masonry chimney extending upwardly to vent above the roof of a house. While these fireplaces may be decorative, their heating efficiency is very low. Further, these fireplaces are necessarily fixed in place and require that a room be decorated around the location of the fireplace.
One way to solve this problem has been to use a zero clearance fireplace. Such fireplaces may be positioned at any desired location in a room. Various designs for such fireplaces have been developed. Some of these fireplaces are designed to be energy efficient, i.e. to transfer some of the heating value of the fuel consumed in the fireplace to the room in which the fireplace is situated.
Such fireplaces are also used for their decorative value. However, due to the heat generated by their use, high efficiency fireplaces may only be utilized in the winter when they are used for their supplemental heating value.


A multi-display device includes at least two flat display panels foldably joined to each other with a border defined therebetween, and a light compensating member for directing light radiated from the panels toward an imaginary plane, extending from a center line of the border of the flat display panels, at a predetermined angle so that the border can be visually compensated.

1. Field of the Invention
The present invention relates to a multi-display device having at least two flat display panels joined to one another and, more particularly, to a multi-display device having an improved display quality by visually compensating for a border defined between the joined flat display panels.
2. Description of the Related Art
A liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), and an electro luminescent display (EL) are well known exemplars of flat display devices.
In recent years, such flat display devices have been widely employed for a computer monitor and a wall-mounted television, as they are lightweight and thin in profile, in addition to being flat.
A common trend is to enlarge the size of the flat display to enhance use as a multi-media display. To enlarge a screen of a unit of display panel however, difficult and complicated technology is required; this increases manufacturing time and costs.
To solve the above problems, a foldable flat display device has been developed to reduce the size of the device.
As shown in FIG. 12, a conventional foldable flat display device is generally comprised of two display panels 2 and 4 pivotally joined to each other. However, in the conventional foldable flat display, because of a border 6 defined between adjacent sides of the panels 2 and 4, a user is able to see a clear separation between the panels 2 and 4.
That is, protecting films 10 are attached on the respective display panels 2 and 4. When considering that each of the protecting films 10 has a thickness of about 0.1 mm, a thickness of a sealant 8 is about 0.1 mm, and a gap G defined between adjacent sides of the panels 2 and 4 is about 0.1 mm, the whole width of the border 6 between actual display parts of the panels 2 and 4 becomes at least 0.5 mm. Therefore, the wide border 6 causes deterioration in the display quality of the device.
Therefore, the present invention has been made in an effort to solve the above described problems.
It is an objective of the present invention to provide a multi-display device having at least two display panels foldably joined to each other, in which a border defined between actual display screens of the display panels is visually compensated for so that the user cannot see any separation between the two panels, thereby improving display quality.
To achieve the above objective, the present invention provides a multi-display device comprising at least two flat display panels foldably joined to each other with a border defined therebetween, and light compensating means for directing light radiated from the panels toward an imaginary plane extending from a center line of the border of the flat display panels.
Each of the flat display panels is selected from the group of a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), and an electro luminescent display (EL).
The multi-display device may further comprise a protecting film attached on screen surfaces and adjacent side walls of the flat display panels.
According to a first embodiment of the present invention, the light compensating means comprises a plurality of inclined films disposed on the flat display panels and inclined toward the imaginary plane at a predetermined angle with respect to the screen surface of the flat display panels and a transparent member disposed between the inclined films.
The predetermined angle of the inclined films is gradually increased as the inclined films are distanced from the border. The inclined films are made of metal or resin, and the transparent member is made of resin.
According to a second embodiment of the present invention, the light compensating means comprises compensating lenses each disposed on the screen surfaces of the flat display panels such that each of the compensating lenses can cover the border and at least a row of pixels which is adjacent to the border.
A length L1 of a portion covered by the compensating lenses is set according to a following formula,
L1=L2/M
where L2 is a length of each pixel which is not covered by the compensating lenses and M is a magnifying force of the compensating lens.
The multi-display device may further comprise transparent layers deposited on a portion of the screen surfaces of the flat display panels, which is not covered by the compensating lenses.
In the above embodiments, the multi-display device may further comprise a diffuser disposed on the light compensating means.
Alternatively, one of adjacent walls of the flat display panels may be designed to be inclined at an angle of 1xc2x0-30xc2x0 with respect to a plane vertical to the screen surface.