A flex circuit for a tape drive includes an elongated flexible printed circuit substrate carrying a pattern of electrical circuit interconnections and divided into a read channel portion for direct connection to multiple read and write heads of a tape head array and carrying a plurality of read channel preamplifiers connected to receive and amplify read signals from a plurality of read heads; a write channel portion including an external connection region for enabling signal and power connections to be made with a host circuit module, the write channel portion including a plurality of write channel drivers; and, a dynamic flexing portion separating and interconnecting the read channel portion and the write channel portion, the dynamic flexing portion adjusting in contour as positional adjustments are made to the head array by a head positioning mechanism. As a related aspect, the flex circuit is secured to a head mounting plate which secures the tape head array, thereby forming a stand-alone multi-track tape head module.

Tape recording and reproducing systems for use as computer data storage devices are required to provide increasingly high data transfer rates and to perform a read verification upon all data being written to tape. Streaming tape drives are so named because multiple blocks of user data are typically written to tape in a single streaming operation, rather than as a series of start-stop operations. Digital linear tape drives are an improved species of streaming tape drives.
In order to increase data density in streaming tape drive systems, track widths are decreasing, while data transfer rates are increasing. It is practical to provide e.g. approximately 128 linear data tracks within a one-half inch wide tape with current technology. One way to increase track densities is to employ azimuth recording techniques in which the tape head structure is canted at a particular offset angle relative to longitude and direction of travel of the tape. At the same time, the digital linear tape drive should be backwardly compatible with tapes which may have been recorded with conventional longitudinal recording techniques. Azimuth recording technology, together with a continuing requirement for backward compatibility, has resulted in tape head structures which include a higher number of write elements, and has required a more complex head positioning mechanism which provides both transverse (up and down) as well as azimuth angle positioning of the tape head structure.
With a relatively high number of narrow-width data tracks, great care must be taken in accurately positioning the tape head structure and in providing efficient electronics for amplifying signals read back by read elements from the tape, and for driving write head elements with signals to be written to the tape. Also, interconnecting read and write data signals between a tape head array and associated electronics poses several concerns. These concerns include susceptibility to electrical noise and crosstalk between channels, parasitic capacitance and inductance, mechanical forces unwantedly applied to the head positioning mechanism, cabling and manufacturing costs, head maintenance and upgrades, and availability of circuit board space.
Flex circuits have been used in the mass storage art to provide flexible electrical connections to magnetic recording/playback heads. Flex circuits have been frequently employed in hard disk drives to provide flexible circuit connections, as well as a mounting substrate for carrying discrete and integrated electronics circuitry in order to position playback preamplifier circuitry close to the read head elements in order to improve signal to noise ratios. One example of a flex circuit for a hard disk drive employing a rotary voice coil head positioner is given in U.S. Pat. No. 5,055,969 to Putnam, entitled: "Servo/Data Actuator Arm Flexible Circuit", the disclosure being incorporated herein by reference.
Flexible substrates providing flexible circuit paths have also been proposed for use with tape recording systems. Examples include U.S. Pat. No. 5,134,252 to Himeno et al., entitled: "Signal Line", and U.S. Pat. No. 5,051,366 to Anderson et al, entitled: Electrical Connector". The Himeno et al. patent describes a flexible circuit carrying magnetically shielded signal paths between a rotary head drum of a digital audio tape recorder and external read preamplifier/write driver circuitry. The Anderson et al. patent describes a connector mechanism for interconnecting flexible circuits of a tape head module to flexible circuits extending from separate read and write circuit cards of e.g. an IBM 3490 Tape Drive. While these patents suggest the use of flexible circuits within tape drives, they do not overcome or suggest any solutions to a number of serious problems confronting streaming tape drives for azimuth as well as longitudinal recording, achieved with a multi-dimension positionable head structure.

Multi-channel magnetic tape head module including flex circuit


A method and system are provided for calculating the total service capacity for multimedia traffic under aggregate traffic conditions within a shared transmission medium, such as an ATM network. A total number of different types of telecommunication traffic is specified by the network operator or network designer. Each different type of network telecommunication traffic is referred to as a service. Next, each week is partitioned into several busy periods. This partitioning is provided by the network operator and may include multiple days, for example: Monday-Friday; and, Saturday-Sunday. Thereafter, for each busy day described above, the day is further partitioned into several busy periods, each period discernible from a previous period by the level of activity expected within the network at that time. For example, 8:00 a.m.-5:00 p.m.; and, 5:00 p.m.-7:00 a.m. Once again, this information is provided by the network operator or network designer. Thereafter, for each busy period identified and for each service a specification of the length of that period, a probability that a user will access the service during that busy period, a percentage of all subscribers who subscribe to and use that particular service and the average session duration are specified. These values may be obtained from measurements, research literature or from standards bodies. The simultaneous capacity for each busy period for each service is then calculated. These inputs may then be utilized to calculate the total service capacity for the network. That is, the maximum number of users which can subscribe to each service within the network.

1. Technical Field
The present invention relates to improvements in network design and in particular to improved methods and systems for capacity calculation in a shared transmission medium network. Still more particularly, the present invention relates to a method and system for service capacity calculation for multimedia services under aggregate traffic conditions in a network having identifiable busy periods.
2. Description of the Related Art
No where has the explosion of modern technology been more evident than in the field of communication. The number and type of communication services has been rapidly expanding, including so-called "multimedia" services such as video teleconferencing, video/movies on demand and the like.
The intermixing of these multimedia services with traditional data and voice communications within a shared transmission medium has presented various design problems. For example, consider a system which receives packetized telecommunication traffic from n multimedia services which are queued either in one central queue or in multiple distributed queues wherein one queue is associated with each service. Thus, if more than n subscribers to the services are utilizing the network at any given time, the received packets which are not processed by the system are queued. During heavy use periods, as the number of users increase, and these queues become quite large, certain packets may be discarded based upon a priority scheme and delay will increase and quality of service will suffer.
Consequently, those skilled in the art will appreciate that one design requirement for a viable multimedia network requires that a limit exits for the number of users simultaneously connected to the network so that customer expectations and network efficiency will not suffer.
One common technique utilized in the past to satisfy customer expectations is to ensure that the quality of service parameter values for the multimedia services are not exceeded. In view of the fact that a modern network may include multiple diverse multimedia services having variable quality of service values, this has been very difficult to accomplish.
In the past, attempts at statistically modeling aggregate traffic which originates from homogenous services with similar traffic types and similar characteristics have been proposed. For example, the Poisson Process is widely utilized to model aggregate traffic from voice sources. Similarly, the discreet Auto Regressive Process has been utilized to model aggregate traffic from video-teleconferencing sources. A Markov Modulated Poisson Process is often utilized to model aggregate traffic from data sources. These techniques typically require complex mathematical expressions which are not explicit and which require time-consuming numerical methods to solve.
Service capacity is defined as the maximum number of users that the system can support so that the values of the quality of service parameters are not violated. Thus, while the simultaneous capacity of a multimedia network, i.e. the maximum number of users or subscribers which can simultaneously access individual services within that network so that the values of the quality of service parameters are not violated, can be determined by various techniques, these techniques result in an underestimate of the total service capacity of the network since maximum simultaneous capacity will not be attained constantly. One difficulty utilizing the prior art techniques for extending simultaneous capacity to service capacity is the problem that there may be several busy periods within each day and that there can be several busy days within each week. Thus, techniques for calculating simultaneous capacity for multimedia service within a network have not been generally successful in the calculation of service capacity for a network.
Thus, those skilled in the art will appreciate that a method and system for accurately and efficiently calculating total service capacity of multimedia services under aggregate traffic conditions would greatly enhance the efficiency of network design and the level of customer satisfaction.

Method and system for service capacity calculation for multimedia services under aggregate traffic conditions


A novel composite belt for an desinewing apparatus that uses a belt in combination with a perforated drum. The three layer composite has a monofilament woven polyester carcass between layers of USDA food approved urethane strengthened by adding 10% by weight of ultra high molecular weight polyethylene. The life expectancy of the invention is expected to double that of currently available belts used in such machinery.

1. Field of the Invention
The invention relates to belts for machinery useful for desinewing food products such as meat, poultry and fish.
2. Description of the Related Art
The food processing industry must deal with the problem of separating meat from bones as efficiently as possible. Obtaining meat from the desinewing process that is still raw is far more valuable than obtaining the meat cooked. Raw meat has a substantially higher binding capacity than does cooked meat. Food processors define binding capacity as the ability of meat to form a stable mixture with added fat, water and salt.
Numerous ways have been developed to accomplish the desinewing process with the meat being maintained in the raw state until it is processed at a later stage. U.S. Pat. No. 3,594,190, issued to Eslinger et al. on Jul. 20, 1971, which claims tumbling the meat laden with bones in a drum with a salt brine mixture to remove the bones from the meat. This reference includes a comprehensive yet concise review of the primary techniques for recovering meat from bones.
One class of mechanical devices uses a belt driven mechanism. Representative of this type is U.S. Pat. No. 3,142,860, issued to Churchill on Aug. 4, 1964, which discloses a belt having yieldable frusto-conical projections that engage a platen having frusto-conical projections. When the food to be processed is passed between the belt and platen, the projections tend to shred and remove the meat from the bones.
One widely used mechanical method is the use of a rotating perforated drum and belt apparatus such as manufactured by BAADER food processing machinery. This method of mechanical separation permits a wide range of applications from beef legs to fish. The food to be processed is drawn between the perforated drum and the squeezing belt. The food is subjected to increasing pressure causing the meat to be move into the perforated drum. The hard material such as bones and other sinew are discarded. The recovered desinewed meat is discharged from the drum via an endless screw arrangement.
The advantages of this system are many. The meat is neither ground nor crushed, nor exposed to any thermal load. By selecting different drum sizes, belt sizes and mechanical or hydraulic power appropriately, this type of machine is highly versatile.
The prime difficulty with this type of machine is the belt. The belt serves as the mechanical carrier of the food to be processed to the drum. The belt also provides the pressure which keeps the food product in contact with the rotating drum as the soft material is scraped off, leaving the bone and sinew behind. A typical belt is rubber covered having internal support plies which are also rubber covered and fabric based. The life expectancy of this type of belt is quite short, making frequent replacement necessary.


A method and system for dynamic language modeling of a document are described. In one embodiment, a number of local probabilities of a current document are computed and a vector representation of the current document in a latent semantic analysis (LSA) space is determined. In addition, a number of global probabilities based upon the vector representation of the current document in an LSA space is computed. Further, the local probabilities and the global probabilities are combined to produce the language modeling.

In general, speech recognition is the process of converting acoustic signal into a linguistic message. In certain applications, for example where a speech recognition processor serves as a user interface to a database query system, the resulting message may need to contain enough information to reliably communicate a speaker's goal in accessing the database. However, in an application such as automated dictation or computer data entry, it may be necessary that the resulting message represents a verbatim transcription of a sequence of spoken words. In either case, an accurate statistical, or stochastic, language model is desirable for successful recognition.
Stochastic language modeling places such a role in large vocabulary speech recognition in which it is typically used to constrain the acoustic analysis, guide the search through various (partial) text hypothesis, and/or contribute to the determination of the final transcription. Statistical language models using both syntactic and semantic information have been developed. This approach embeds latent semantic analysis (LSA), which is used to capture meaningful word associations in the available context of a document, into standard n-gram paradigm, which relies on the probability of occurrence in the language of all possible strings of N words.
This new class of language models, referred to as (multi-span) hybrid N-gram plus LSA models have shown a substantial reduction in perplexity. In addition, multi-span models have also been shown to significantly reduce word error rate. However, their overall performance tends to be sensitive to a number of factors. One such factor is the training data used to derive the statistical parameters, in particular those associated with the LSA component. This problem is common in statistical language modeling and can be solved by careful matching or training and test conditions. In addition, a dynamic selection of the LSA context scope during recognition affects the overall effectiveness of the hybrid models.

This patent is subject to a terminal disclaimer.

Method for dynamic context scope selection in hybrid N-GRAM+LSA language modeling


A thermoplastic composition based on a polyolefin and a vinyl aromatic polymer, having an improved combination of physical, mechanical and thermal properties, comprising:. from 40 to 80% by weight of a vinyl aromatic polymer (A) containing, as an elastomeric component, from 0.5 to 5% by weight of a vinyl aromatic monomer - conjugated diene linear block polymer and from 5 to 15% of a diene rubber, from 5 to 50% by weight of a polyolefin (B) and from 10 to 50% by weight of an olefinic elastomer (C) containing, grafted thereon, a vinyl aromatic polymer, wherein the molar ratio between the vinyl aromatic polymer and the olefinic elastomer in the grafted phrase is greater than 0.8, the sum of components (A), (B) and (C) being equal to 100%.

1. Field of the Invention
The present invention relates to thermoplastic compositions based on a polyolefin and a vinyl aromatic polymer. More particularly, the present invention relates to thermoplastic compositions based on a polyolefin and a vinyl aromatic polymer endowed with an optimal combination of properties, including thermoformability, moldability, thermal resistance, modulus, resilience, resistance to naturally-occurring organic substances which tend to accelerate the degradation of some polymers, etc.
2. Description of the Background
Such particular combination of properties makes the compositions of the present invention particularly suitable for the production of shaped articles by any forming technique known for the thermoplastic resins, such as thermoforming, injection molding, forging, rotational molding and the like.
As is known, vinyl aromatic polymers are thermoplastic resins suitable for being transformed, under heating, into shaped articles by injection or extrusion molding. Said vinyl aromatic polymers have a fair tenacity, but they are not suitable for use in applications where a high tenacity associated with good chemical resistance is required.
A way to improve this deficiency in properties is to provide blends with other polymers which do not lack these properties to obtain a material exhibiting the desired combination of properties. However, this approach has only been successful in a few cases; generally, in fact, the blending results in the combination of the worst characteristics of each component, the overall result being a material of such poor properties as not to be of any practical or commercial value.
The reasons for this drawback are the fact that not all polymers are compatible with each other and, therefore, do not perfectly adhere. As a result, interfaces are formed among the components of the blend which represent weakness and breaking points.
More particularly, mixtures based on polystyrene, or generally on a vinyl aromatic polymer or copolymer, either as such or made impact resistant by grafting it onto a rubber, and onto a polyolefin, give rise to blends endowed with heterogeneous structure and mechanical weakness, due to the incompatibility between these two types of polymers.
Many attempts to solve the incompatibility problem have been made by using defined amounts of the two resins and by making use of a so-called compatibilizing agent.
Thus, for example, U.S. Pat. Nos. 4,386,187 and 4,386,188 describe the use of a styrene-butadiene-styrene block copolymer as compatibilizing agent between the polyolefins and a vinyl aromatic polymer.
Published European Patent Application 60, 524 and Japanese Patent Publication (Kokai) 49-28637/1974 describe the use of styrene-butadiene block copolymers to compatibilize blends of a polyolefin with a high impact polystyrene or styrenic resins.
Published European Patent Application 291,352 discloses polymeric compositions comprising a polyolefin and a vinyl aromatic polymer containing, as elastomeric component, small quantities of a vinyl aromatic monomer-conjugated diene linear block polymer, wherein, as a compatibilizing agent, a vinyl aromatic monomer-conjugated diene star-block polymer is used.
In English Patent 1, 363, 466 and in U.S. Pat. No. 4,020,025, hydrogenated styrene-butadiene di-block copolymers are proposed as compatibilizing agents for polyolefin/styrenic polymer blends.
In the published European Patent Application 60525 and U.S. Pat. No. 4,188,432, a hydrogenated styrene-butadiene-styrene block copolymer, i.e. a styrene-ethylene-butylene-styrene copolymer, is blended with styrenic and olefinic polymers.
In general, however, these approaches have not been industrially successful since the resulting blends, even if they are homogeneous, do not exhibit a satisfactory property combination or have other undesirable properties.
Laid-open European Patent Application 195,829 describes the use of an alpha-olefin copolymer grafted vinyl aromatic polymer, as a compatibilizing agent in the polyolefine-vinyl aromatic polymer blends.
The polymeric compositions disclosed in this European Patent Application comprise: at least 20% by weight (preferably between 20 and 90%) of a polyolefin; at least 5% by weight (preferably between 5 and 75%) of a vinyl aromatic polymer and from 2 to 15% by weight of the alpha-olefin copolymer grafted onto a vinyl aromatic polymer.
Also the compositions so obtained, however, do not exhibit a satisfactory combination of properties for all the uses they are intended for. In particular, an acceptable value of resilience (IZOD) may be obtained by using an excess of polyolefin; this increase, however, occurs to the detriment of the modulus property. By increasing, on the contrary, the amount of the vinyl aromatic polymer, the modulus of the composition increases but to the detriment of the resilience thereof which assumes values of poor use interest.

Thermoplastic compositions based on a polyolefine and a vinyl aromaticpolymer


Semiconductor devices and fabrication methods are provided, in which metal transistor gates are provided for MOS transistors. A rare earth-rare earth alloy incorporated metal nitride layer is formed above a gate dielectric. This process provides adjustment of the gate electrode work function, thereby tuning the threshold voltage of the resulting NMOS transistors.

Field effect transistors (FETs) are widely used in the electronics industry for switching, amplification, filtering, and other tasks related to both analog and digital electrical signals. Most common among these are metal-oxide-semiconductor field-effect transistors (MOSFETs), wherein a gate electrode is energized to create an electric field in a channel region of a semiconductor body, by which electrons are allowed to travel through the channel between a source region and a drain region of the semiconductor body. The source and drain regions are typically formed by adding dopants to targeted regions on either side of the channel. A gate dielectric or gate oxide is formed over the channel, and a gate electrode or gate contact is formed over the gate dielectric. The gate dielectric and gate electrode layers are then patterned to form a gate structure overlying the channel region of the substrate.
In operation of the resulting MOS transistor, the threshold voltage (Vt) is the gate voltage value required to render the channel conductive by formation of an inversion layer at the surface of the semiconductor channel. Complimentary MOS (CMOS) devices have become widely used in the semiconductor industry, wherein both n-channel and p-channel (NMOS and PMOS) transistors are used to fabricate logic and other circuitry. For enhancement-mode (e.g., normally off) devices the threshold voltage Vt is positive for NMOS and negative for PMOS transistors. The threshold voltage is dependent upon the flat-band voltage, where the flat-band voltage depends on the work function difference between the gate and the substrate materials, as well as on surface charge.
The work function of a material is a measure of the energy required to move an electron in the material outside of a material atom from the Fermi level, and is usually expressed in electron volts (eV). For CMOS products, it is desirable to provide predictable, repeatable, and stable threshold voltages (Vt) for the NMOS and PMOS transistors. To establish Vt values, the work functions of the PMOS and NMOS gate contact and the corresponding channel materials are independently tuned or adjusted through gate and channel engineering, respectively.
Gate stack engineering is employed to adjust the work function of the gate contact materials, where different gate work function values are set for PMOS and NMOS gates. The need to independently adjust PMOS and NMOS gate work functions has made poly-silicon attractive for use as a gate contact material in CMOS processes, since the work function of poly-silicon can be easily raised or lowered by doping the poly-silicon with p-type or n-type impurities, respectively. The PMOS poly-silicon gates are typically incorporated with p-type impurities and NMOS gate poly-silicon is incorporated with n-type dopants, typically during implantation of the respective source/drain regions following gate patterning. In this way, the final gate work functions are typically near the Si conduction band edge for NMOS and near the valence band edge for PMOS. The provision of dopants into the poly-silicon also has the benefit of increasing the conductivity of the gate electrode. Poly-silicon has thus far been widely used in the fabrication of CMOS devices, wherein the gate engineering provides a desired gate electrode conductivity (e.g., sheet resistance value) by conventional tuning (e.g., implants), and the threshold voltage fine tuning is achieved by tailoring the channel doping level through the Vt adjust implants.
FIG. 1 illustrates a conventional CMOS fabrication process 10 beginning at 12, in which front end processing is performed at 14, including well formation and isolation processing. At 16 and 18, channel engineering is performed (e.g., Vt adjust, punch-thru, and channel stop implants) for PMOS and NMOS regions, respectively. A thin gate dielectric and an overlying poly-silicon layer are formed at 20 and 22, respectively, and the poly-silicon is patterned at 24 to form gate structures for the prospective NMOS and PMOS transistors. The gate structures are then encapsulated at 26, typically through oxidation, and highly-doped drain (HDD) implants are performed at 28 to provide p-type dopants to prospective source/drains of the PMOS regions and n-type dopants to source/drains of the NMOS regions, using the patterned gate structures and isolation structures as an implantation mask. Sidewall spacers are then formed at 30 along the lateral sidewalls of the gate structures.
At 32, the PMOS source/drain regions and the PMOS poly-silicon gate structures are implanted with p-type dopants to further define the PMOS source/drains, and to render the PMOS gates conductive. Similarly, the NMOS source/drain regions and the NMOS poly-silicon gate structures are implanted at 34 with n-type dopants, further defining the NMOS source/drains and rendering the NMOS gates conductive. Thereafter, the source/drains and gates are silicided at 36 and back end processing (e.g., interconnect metalization, etc.) is performed at 38, before the process 10 ends at 40. In the conventional process 10, the channel engineering implants at 16 and 18 shift the Vt of the PMOS and NMOS channel regions, respectively, to compensate for the changes in the PMOS and NMOS poly-silicon gate work functions resulting from the source/drain implants at 32 and 34, respectively. In this manner, the desired work function difference between the gates and channels may be achieved for the resulting PMOS and NMOS transistors, and hence the desired threshold voltages.
The gate dielectric or gate oxide between the channel and the gate electrode is an insulator material, typically SiO2 or other dielectric, that operates to prevent current from flowing from the gate electrode into the channel when a voltage is applied to the gate electrode. The gate dielectric also allows an applied gate voltage to establish an electric field in the channel region in a controllable manner. Continuing trends in semiconductor product manufacturing include reduction in electrical device feature sizes (scaling), as well as improvements in device performance in terms of device switching speed and power consumption. MOS transistor performance may be improved by reducing the distance between the source and the drain regions under the gate electrode of the device, known as the gate or channel length, and by reducing the thickness of the layer of gate dielectric that is formed over the semiconductor surface.
However, there are electrical and physical limitations on the extent to which SiO2 gate dielectrics can be made thinner. These include gate leakage currents tunneling through the thin gate oxide, limitations on the ability to form very thin oxide films with uniform thickness, and the inability of very thin SiO2 gate dielectric layers to prevent dopant diffusion from the gate poly-silicon into the underlying channel. Accordingly, recent scaling efforts have focused on high dielectric constant (high-k) materials having dielectric constants greater than that of SiO2, which can be formed in a thicker layer than scaled SiO2, and yet which produce equivalent field effect performance. A physically thicker high-k dielectric layer can thus be formed to avoid or mitigate tunneling leakage currents, while still achieving the required electrical performance equivalent (e.g., capacitance value) to a thinner SiO2.
Thus, while poly-silicon gate electrodes have previously offered flexibility in providing dual work functions at the band edges for CMOS processes, the future viability of conventional poly-silicon gate technology is lessened as scaling efforts continue. Accordingly, attention has recently been directed again to the possibility of using metal gate electrodes in CMOS products.
It has also been proposed to utilize high-k dielectric materials in combination with a rare earth metal and mid-gap metal nitride to lower the work function of NMOS metal gates. The rare earth metal is provided in a relatively high concentration, up to around 8 atomic percent, in the mid-gap nitride metal. These proposals, however, result in degradation of electron mobility due to the rare earth metal diffusion into the gate dielectric/silicon substrate interface.
There remains a need for dual or differentiated work function capability (e.g., for PMOS and NMOS transistors) in CMOS processes. In this regard, metal work functions are not shifted as easily by the same amounts as was the case for poly-silicon. Accordingly, there is a need for improved CMOS transistor metal gate designs and fabrication techniques by which the benefits of scaling can be achieved while reducing or eliminating the degradation of electron mobility.

Formation of metal gate electrode using rare earth alloy incorporated into mid gap metal


A magnetic head having a recording and/or reproducing magnetic gap and an erasing magnetic gap for writing and/or reading informational signals on and/or from a flexible disk is disclosed. A magnetic circuit comprises a front core having center cores and side cores and a rear core. The front core is sandwiched between a pair of sliders for assuring contact with the flexible disk. At least one of the sliders is provided with core reinforcing portions in positions corresponding to the cores and the side cores of the front core. The core reinforcing portions are in contact with the center cores and the side cores for reinforcing these cores.

The present invention relates to a magnetic head which is preferred for recording and/or reproducing informational signals on and/or from a floppy disk.
A magnetic head for recording and/or reproducing informational signals on and/or from a floppy disk having a magnetic head element sandwiched between a pair of sliders in which a magnetic circuit comprises a front core 51 which is formed with a recording and reproducing magnetic gap G.sub.1 and an erasing magnetic gap G.sub.2, a rear core 52 which is substantially E-shaped in plan and is magnetically coupled with the front core 51 to form a closed magnetic path and a pair of coil bobbins on which driving coils 53 and 54 are wound has heretofore been proposed (see FIG. 8).
In this prior art magnetic head, the front core 51 comprises a pair of bar-like center cores 59 and 60 which are integrally bonded together and a pair of L-shaped side cores 61 and 62 which sandwich the pair of center cores 59 and 60 therebetween so that a recording and reproducing magnetic gap G.sub.1 and an erasing magnetic gap G.sub.2 are formed between the center cores and the side cores. The rear core 52 is formed into a shape corresponding to that of the front core 51 and comprises center legs 63 and 64 and side legs 65 and 66 in such positions they face to the center cores 59 and 60 and the side cores 61 and 62 of the front core 51, respectively. The front and rear cores 51 and 52 have the facing side cores 61 and 62 and the side legs 65 and 66 which are inserted into the coil bobbins 55 and 56 in such a manner that they are stepwise overlapped and magnetically and mechanically coupled together by a simultaneously inserted leaf spring and the like.
The center cores 59 and 60 and the side cores 61 and 62 of the front core 51 are as very thin as about 0.3 mm in thickness to achieve miniaturization of the floppy disk. Accordingly, the center cores 59 and 60 and the side cores 61 and 62 may be easily damaged when they are installed on the coil bobbins 55 and 56 or secured to the rear core 52.
Since the mechanical strength of the side cores 61 and 62 is low, contact of the side cores 61 and 62 with the rear core 52 is not stable and a space may be easily formed in the bonding interface therebetween. Stabilization of the electromagnetic conversion characteristics can not be achieved with this prior art magnetic head. Further, since the sliders 57 and 58 which are provided for assuring the characteristics of the contact of the front core 51 with the floppy disk should be provided with escapements 67 and 68 for the coil bobbins 53 and 54, respectively, the bonding sides 57a and 58a for supporting the front core 51 becomes so small that a bonding strength sufficient to secure the front core 51 can not be assured. This may cause cracking in the bonding portion between the front core 51 and the sliders 57 and 58 when a groove is formed on the sliders 57 and 58 after assembly of the head components.


An image forming apparatus such as a copier or a printer for forming an image of a document on a recording paper. The image forming apparatus includes a paper feed tray for holding the recording paper; a conveyance unit for conveying the recording paper from the paper feed tray; a image forming section for forming a toner image of the document onto the recording paper; a fixing unit for fixing the toner image on the recording paper; a detector for detecting a paper jam between the units, and for generating a detection signal; a locking member with a solenoid for locking one of the units in another; a controller for controlling the locking member according to the detection signal so that both of the units are resisted from being removed separately when the paper jam occurs between the units.

The present invention relates to a jam clearance and unit pullout means effectively used when a jam that occurs, for example, between a paper conveyance unit and a paper feed tray unit provided in an image forming apparatus such as a copier and an image scanner.
In general, an electrophotographic image forming apparatus such as a copier and an image scanner comprises: a platen on which a document is set; an optical scanning system including a document illuminating lamp and a reflecting mirror, which are reciprocated under the platen, and also including a projection lens and a reflecting mirror, which are fixed; a rotational photoreceptor drum that is charged to a predetermined potential by a charging electrode; a developing unit that develops an electrostatic latent image formed on the photoreceptor drum, with toner; a transfer electrode that transfers the formed toner image onto a recording paper, which is a transfer sheet, conveyed toward the photoreceptor drum; a separation electrode; a discharge electrode; a fixing unit to fix the toner image transferred onto the recording paper surface; and a cleaning unit to remove residual toner and dust on the photoreceptor drum surface.
Predetermined toner images are successively recorded on the recording papers intermittently conveyed in a predetermined conveyance passage.
In the apparatus described above, the paper feed conveyance unit, fixing unit including a paper discharge roller and a plurality of paper feed tray units are constructed so that they can be respectively pulled out from the image forming apparatus. For example, when a paper jam occurs in the paper feed conveyance unit, the unit is pulled out for jam clearance, that is, the jammed recording paper is removed.
However, for example, in the case where a conveyed recording paper is jammed between the paper feed conveyance unit and the paper feed tray unit, the jammed recording paper is damaged when one of the units is carelessly pulled out. To remove the damaged recording paper from one of the units costs much labor. When the jam clearance operation is not performed completely, the successive recording papers are also jammed.
In the case where the image forming apparatus is constructed so that each unit can be pulled out, the following problems may be encountered: In the case where a plurality of units are carelessly pulled out at the same time, the balance of the apparatus is lost so that the apparatus falls down. Further, when the apparatus is designed, dead spaces are unnecessarily formed, so that the apparatus can not be made compact. Even when the units are overlapped so as to make the apparatus compact, there is a possibility that the photoreceptor drum or another unit is damaged when each unit is not pulled out in a predetermined order.
The present invention is to overcome the above disadvantages. It is an object of the present invention to provide an image forming apparatus characterized in that: even when a recording paper is jammed between two units, it can be easily, positively and quickly removed without being damaged; and when the units are pulled out for jam clearance, there is no possibility that the balance of the apparatus is lost, and that the units are pulled out in wrong order thereby affecting other units.

Image forming apparatus provided with unit locking means


A Giant Magneto-Resistive (GMR) sensor (900) having Current Perpendicular to Plane (CPP) structure provides an extended first pinned layer (914) as compared to second pinned layer (912) and free layer (910). Increased magnetoresistance changes, increased pinning strength, increased thermal stability, and decreased susceptibility to Electro-Static Discharge (ESD) events is realized by maintaining equivalent current densities through free layer (910) and second pinned layer (912), while decreasing the relative current density through first pinned layer (914).

1. Field of the Invention
This invention relates in general to spin valve heads for magnetic storage systems, and more particularly to a method and apparatus for an extended self-pinned layer for a Current Perpendicular to Plane (CPP) head.
2. Description of Related Art
Magnetic recording is a key and invaluable segment of the information-processing industry. While the basic principles are one hundred years old for early tape devices, and over forty years old for magnetic hard disk drives, an influx of technical innovations continues to extend the storage capacity and performance of magnetic recording products. For hard disk drives, the areal density or density of written data bits on the magnetic medium has increased by a factor of more than two million since the first disk drive was applied to data storage. Since 1991, areal density has grown by a 60% compound growth rate, which is based on corresponding improvements in heads, media, drive electronics, and mechanics.
Magnetic recording heads have been considered the most significant factor in areal-density growth. The ability of the magnetic recording heads to both write and subsequently read magnetically recorded data from the medium at data densities well into the Gigabits per Square Inch (Gbits/in2) range gives hard disk drives the power to remain the dominant storage device for many years to come.
Important components of computing platforms are mass storage devices including magnetic disk and magnetic tape drives, where magnetic tape drives are popular, for example, in data backup applications. The magnetic disk drive includes a rotating magnetic disk, write and read heads that are suspended by a suspension arm above the rotating magnetic disk and an actuator that swings the suspension arm to place the read and write heads over selected circular tracks on the rotating disk. The read and write heads are directly mounted on a slider that has an Air-Bearing Surface (ABS) between the slider and the rotating disk. The suspension arm biases the slider into contact with the surface of the magnetic disk when the magnetic disk is not rotating. However, when the magnetic disk rotates, air is swirled by the rotating disk adjacent to the ABS causing the slider to ride on a cushion of air just above the surface of the rotating magnetic disk. The write and read heads are employed for writing magnetic data to and reading magnetic data from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a computer program to implement the write and read functions.
A magnetoresistive (MR) sensor detects magnetic field signals through the resistance changes of a sensing element as a function of the strength and direction of magnetic flux being sensed by the sensing element. Conventional MR sensors, such as those used as MR read heads for reading data in magnetic recording disk and tape drives, operate on the basis of the anisotropic magnetoresistive (AMR) effect of the bulk magnetic material, which is typically a perm-alloy. A component of the read element resistance varies as the square of the cosine of the angle between the magnetization direction in the read element and the direction of sense current through the read element. Recorded data can be read from a magnetic medium, such as the magnetic disk in a magnetic disk drive, because the external magnetic field from the recorded magnetic medium (the signal field) causes a change in the direction of magnetization in the read element, which in turn causes a change in resistance of the read element and a corresponding change in the sensed current or voltage.
In the past several years, prospects of increased storage capacity have been made possible by the discovery and development of sensors based on the giant magnetoresistance (GMR) effect, also known as the spin-valve effect. In the spin valve sensor, the GMR effect varies as the cosine of the angle between the magnetization of the pinned layer and the magnetization of the free layer. Recorded data can be read from a magnetic medium because the external magnetic field from the recorded magnetic medium, or signal field, causes a change in the direction of magnetization of the free layer, which in turn causes a change in the resistance of the spin valve sensor and a corresponding change in the sensed current or voltage.
Magnetic sensors utilizing the GMR effect are found in mass storage devices such as, for example, magnetic disk and tape drives and are frequently referred to as spin-valve sensors. The spin-valve sensors being divided into two main categories, the Anti-FerroMagnetically (AFM) pinned spin valve and the self-pinned spin valve. An AFM pinned spin valve comprises a sandwiched structure consisting of two ferromagnetic layers separated by a thin non-ferromagnetic layer. One of the ferromagnetic layers is called the pinned layer because it is magnetically pinned or oriented in a fixed and unchanging direction by an adjacent AFM layer, commonly referred to as the pinning layer, which pins the magnetic orientation of the pinned layer through anti-ferromagnetic exchange coupling. The other ferromagnetic layer is called the free or sensing layer because the magnetization is allowed to rotate in response to the presence of external magnetic fields.
In the self-pinned spin valve, the magnetic moment of the pinned layer is pinned in the fabrication process, i.e.—the magnetic moment is set by the specific thickness and composition of the film. The self-pinned layer may be formed of a single layer of a single material or may be a composite layer structure of multiple materials. It is noteworthy that a self-pinned spin valve requires no additional external layers applied adjacent thereto to maintain a desired magnetic orientation and, therefore, is considered to be an improvement over the anti-ferromagnetically pinned spin valve.
Recent hard disk drive designs have utilized the Current In-Plane (CIP) head, where the sense current travels between the magnetic shields parallel to the sensor plate. Such a design yields optimism to suffice up to areal densities close to 100 Gbits/in2, however, research efforts continue to find even better read heads so that areal densities may be boosted into the many hundreds of Gbits/in2 range.
One such discovery is the Current Perpendicular to Plane (CPP) head, whereby the sense current travels from one magnetic shield to the other, perpendicular to the sensor plate. The CPP head provides an advantage over the CIP head because as the sensor size becomes smaller, the output voltage of a CPP head becomes larger, thus providing an output voltage that is inversely proportional to the square root of the sensor area.
One of the candidates for realizing high sensitivity using the CPP structure is the Tunnel-Magneto-Resistive (TMR) head. In a TMR head, the magnitude of the tunneling current, in the gap between two ferromagnetic metals, is dependent upon the electron's spin directions or polarizations. The TMR head, however, has several disadvantages including a large resistance due to the barrier layer, which limits the operating frequency and makes the Johnson and Shot noise high. A breakthrough in fabrication technology is thus required to lower the resistance of the barrier layer before the TMR head becomes a viable CPP option.
Another candidate for the CPP structure uses a multilayer GMR structure that exhibits a large output signal, but has other problems such as the generation of hysteresis and the magnetic domains of their read elements are difficult to control. Moreover, if in-gap type read heads are used for high-density recording, the sensor films must be thinner than the read gap.
Other candidates for the CPP structure use a Spin Valve (SV) arrangement for ultra-high density recording. However, the MR ratio of a CPP element having a conventional SV is a very low percentage and its output voltage, which is related to the resistance change, is too low.
It can be seen therefore, that there is a need for an improved CPP head structure utilizing the SV that exhibits an increased magnetoresistance change, while maintaining control of its magnetic domain.

Apparatus for extended self-pinned layer for a current perpendicular to plane head

Hitachi Global Storage Technologies Netherlands B.V.


An ultraviolet optical device includes optical parts on which an ultraviolet ray is irradiated. Some or all of the optical parts are arranged in an envelope having a gas inlet port and a gas output port. In the envelope (9), a dry gas having an amount of moisture (as volume fraction) of 5,000 [ppm] or less and led from the gas inlet port (10) is sprayed on an optical part in which at least a deterioration in optical characteristics is especially a problem, so that an improvement in the secular change of the optical part can be achieved.

The present application claims priority to Japanese Application No. P11-161253 filed Jun. 8, 1999 and Japanese Application No. P11-161252 filed Jun. 8, 1999, which applications are incorporated herein by reference to the extent permitted by law.
1. Field of the Invention
The present invention relates to an ultraviolet optical device, e.g., an ultraviolet ray generation device, or an ultraviolet optical device such as an exposure device using an ultraviolet ray.
2. Description of the Prior Art
Conventionally, an ultraviolet ray having a wavelength of 400 nm or less is irradiated on an optical part in the atmosphere. Moisture and oil from the atmosphere that are on the surface of the optical part react, and reactants, peripheral particles, and the like adhere to the surface of the optical part. As a result, the optical characteristics of the optical part are inconveniently deteriorated.
Particularly, in waveform conversion (M. Oka and S. Kubota, JJAP. Vol. 31 (1992) pp 513 or M. Oka et. al., of Conference on Laser and Electro-Optics (OSA, Washington D.C., 1992) or the like of an external resonator type, a small deterioration in performance of a mirror or a nonlinear optical element arranged in a resonator considerably reduces a harmonic output which is generated.
For example, an ultraviolet optical device of an external resonator type, which converts, e.g., a fundamental wave having a wavelength of 532 nm into an ultraviolet ray having a wavelength of 266 nm in a resonator, has first to fourth mirrors 1 to 4 constituting an external resonator as shown in FIG. 20. The first to third mirrors 1 to 3 are constituted by high-reflectance mirrors each having a reflectance of, e.g., 99.95% or more with respect to the wavelength of 532 nm of the fundamental wave, and the fourth mirror 4 is constituted by a mirror having a reflectance of, e.g., 99% or more with respect to the wavelength of 532 nm.
Between the first and fourth mirrors 1 and 4, a nonlinear optical element 5, e.g., barium borate xcex2-BaB2O4 (to be referred to as BBO hereinafter) is arranged. Both the end faces, i.e., a light-incidence end face 5a and a light-emission end face 5b of the nonlinear optical element 5 are polished into mirror planes, respectively, to form low-reflectance films each having a reflectance of 0.1% or less with respect to the wavelength of 532 nm of the fundamental wave.
With this configuration, incident light 6, i.e., a fundamental wave having the wavelength of 532 nm and reaching through the fourth mirror 4, is amplified among the first to fourth mirrors 1 to 4, and an ultraviolet ray having a wavelength of 266 nm of the second harmonic wave of the fundamental wave is led by the nonlinear optical element 5 from the light-emission end face 5b. An ultraviolet ray obtained by waveform conversion as described above is output as emission light 7 through the first mirror having a transmittance which is high with respect to the wavelength of the ultraviolet ray.
In the external resonator, the third mirror 3 is arranged in an actuator (not shown) constituted by, e.g., a so-called VCM (Voice Coil Motor), and the position of the third mirror 3 is adjusted.
When the wavelength conversion is performed in the atmosphere, the optical characteristics of the mirrors constituting the external resonator deteriorate. More specifically, an optical loss caused by enlargement of scattering increases. In particular, on the light emission end face side of the nonlinear optical element, which receives large quantity of ultraviolet light, i.e., light having a short wavelength of 400 nm or less, an optical loss on the first mirror 1 in FIG. 20 considerably increases.
This optical loss and an output Pxcfx89 obtained by amplifying the fundamental wave having a wavelength of 532 nm in the external resonator are expressed by the following equation (11):
Pxcfx89=(xcex4cav2+4xcex3SHPixe2x88x92xcex4cav)/2xcex3SHxe2x80x83xe2x80x83(11)
where, xcex4cav is an optical loss at a wavelength of 532 nm in the external resonator, Pxcfx89 is an output of an amplified fundamental wave, Pi is an output of an incident fundamental wave on to the nonlinear optical element 5, and xcex3SH is a constant which is called a nonlinear conversion factor determined on the basis of the crystal length of the nonlinear optical element 5, the wave length of the fundamental wave, the spot size of the incident fundamental wave, and a focusing parameter.
According to equation (11), it is understood that, when the optical loss xcex4cav increases, the output Pxcfx89 of the fundamental wave decreases.
On the other hand, the relationship between the output Pxcfx89 of the fundamental wave and an output P2xcfx89 of a second harmonic wave can be expressed by the following equation (12):
P2xcfx89=xcex3SHPxcfx892xe2x80x83xe2x80x83(12)
According to equation (12), it is understood that, when the output Pxcfx89 of the fundamental wave decreases, the output P2xcfx89 of the second harmonic wave also decreases.
Actually, with the configuration in FIG. 20, when a secular change in output was measured, where ultraviolet light was generated in the atmosphere in a clean room (volume fraction of moisture amount of about 8,000 [ppm]), the results shown in FIG. 18 were obtained.
As is apparent from the results, an ultraviolet output becomes half about 47 hours after in the atmosphere having the moisture amount, after which ultraviolet light cannot be stably obtained.
However, in an ultraviolet generation device used as a light source of, e.g., an exposure device in photolithographic techniques for making a semiconductor device or other various devices or the like, it is desirable to have stability for about 200 hours, and desirable to have at least the half-value period of the output for 200 hours or longer.
The present invention makes it possible to obtain an ultraviolet optical device having an optical part which is subjected to ultraviolet irradiation according to the above-described object.
The present invention makes it possible to obtain an ultraviolet optical device comprising an optical part on which an ultraviolet ray is irradiated, which meets the above-described object.
The present invention is an ultraviolet optical device comprising optical parts on which an ultraviolet ray is irradiated, wherein some or all of the optical parts are arranged in an envelope having a gas inlet port and a gas output port, and a dry gas led from the gas inlet port is sprayed on an optical part, which has a problem of deterioration in its optical characteristics.
The ultraviolet optical device according to the present invention is an ultraviolet optical device, having a nonlinear optical element in a resonator, for generating an ultraviolet ray, wherein the relationship between time T [time] at which an ultraviolet output is x [%] with respect to an initial output and a volume fraction Rw [ppm] of moisture of an arrangement portion of all or some of the optical parts on which the ultraviolet ray is irradiated is expressed by the following expression:
Txe2x89xa7(5xc3x97104xcex3SH0.5PUVxe2x88x920.5 exp(xe2x88x920.00081381xc2x7Rw))xc3x97(xe2x88x92Pi+PUV+xxe2x88x920.5(Pixe2x88x92PUV/2))xe2x80x83xe2x80x83(1)
where, Pi, PUV, and xcex3SH are constants,
Pi is an output [W] of an incident fundamental wave onto the nonlinear optical element,
PUVis an ultraviolet output [W] on an emission end face of the nonlinear optical element, and
xcex3SH is a nonlinear conversion factor [Wxe2x88x921]).
In addition, the ultraviolet optical device according to the present invention is an ultraviolet optical device, having a nonlinear optical element in a resonator, for generating an ultraviolet ray, wherein the relationship between an increase in in-resonator loss xcex94xcex4/xcex94T [%/hour] per unit time and a volume fraction Rw [ppm] of moisture of an arrangement portion of all or some of the optical parts on which the ultraviolet ray is irradiated is expressed by the following expression:
xcex94xcex4/xcex94Txe2x89xa62xc3x9710xe2x88x925 exp(xe2x88x920.00081381xc2x7Rw)xe2x80x83xe2x80x83(3).
As described above, according to the present invention, it is confirmed that the deterioration in optical characteristics of an optical part on which an ultraviolet ray is irradiated can be considerably reduced by actively spraying the dry gas.
In each of the devices according to the present invention, an amount of moisture in the arrangement portion of the optical part on which the ultraviolet ray is irradiated is selected to reduce an ultraviolet output, i.e., to set the life time of the optical part.

Ultraviolet optical device having an optical part with a gas sprayed thereon


A liquid crystal display device includes: a first substrate; a second substrate which is placed nearer to a viewer than the first substrate, and which faces a viewer side of the first substrate; a liquid crystal sandwiched between the first substrate and the second substrate; an upper polarization plate which is placed nearer to the viewer than the second substrate, and which faces a viewer side of the second substrate; and a transparent resin plate which is placed nearer to the viewer than the upper polarization plate, and which is attached to a viewer side of the upper polarization plate with one of an adhesive material and a bonding material, the transparent resin plate includes a transparent oxide film on a face that faces the upper polarization plate, and the transparent resin plate is in close contact with the adhesive material or the bonding material through the transparent oxide film.

1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly, to a technique effectively applied to a liquid crystal display device that is used as a display of a portable electronic device.
2. Description of the Related Art
Liquid crystal display devices are one of devices that have conventionally been used as a display of a portable electronic device such as a cellular phone and a personal digital assistant (PDA).
Liquid crystal display devices are display devices that have a liquid crystal display panel in which a liquid crystal is sealed between a first substrate and a second substrate. The components of the liquid crystal display panel are arranged such that the liquid crystal and the second substrate are nearer to a viewer (person viewing the display panel) than the first substrate.
In a general liquid crystal display device, the first substrate is an insulating substrate, for example, a glass substrate. Scanning signal lines, video signal lines, TFT elements, pixel electrodes, an orientation film, and others are formed on a surface of the first substrate, which is why the first substrate is often called a TFT substrate. The second substrate is an insulating substrate, for example, a glass substrate, and is often called an opposite substrate. Formed on a surface of the second substrate are a light-shielding layer, which divides a display area into pixels, a color filter, an orientation film, and others. Opposite electrodes, which are provided to drive the liquid crystal together with the pixel electrodes, are formed on the opposite substrate side in some cases, and on the TFT substrate side in other cases.
Recent portable electronic devices are ever becoming thinner and lighter, prompting liquid crystal display devices (liquid crystal display panels) and other displays for portable electronic devices to be thinner. One way to obtain a thinner liquid crystal display panel is to reduce the thickness of the insulating substrate (glass substrate) in one or both of the TFT substrate and the opposite substrate.
Another way to obtain a thinner liquid crystal display panel has lately been proposed in which one or both of the TFT substrate and the opposite substrate employ plastic substrates (resin substrates) as insulting substrates instead of glass substrates (see, for example, JP 08-006039 A).
Conventionally, a liquid crystal display device used in a cellular phone or other portable electronic devices is often built inside a casing (exterior parts) of the portable electronic device which has an opening in a portion corresponding to a display area of the liquid crystal display panel. The opening in the casing is, in most cases, covered with a protective cover made of acrylic resin or the like in order to protect the liquid crystal display panel. This structure is beginning to make further thickness reduction of the display part of a cellular phone difficult, and has problems such as lowered visibility of displayed video or images due to a layer of air between the liquid crystal display panel and the protective cover.
A solution for making it possible to further reduce the thickness of a liquid crystal display device for cellular phones and the like while preventing the visibility of displayed images or the like from dropping has been proposed in which a resin plate functioning as the protective cover is attached to a face of the liquid crystal display panel that faces the viewer. The resin plate is attached to the liquid crystal display panel, by attaching the resin plate to a polarization plate that is nearer to the viewer than the opposite substrate (second substrate) with, for example, an adhesive or bonding material so that the resin plate and the polarization plate are in close contact with each other.
Attaching the resin plate to the polarization plate with an adhesive or bonding material has a problem in that, if the adhesive or bonding material is the same acrylic resin-based adhesive or bonding material that is used to attach an upper polarization plate to an insulating substrate (glass substrate) constituting the opposite substrate, the adhesion of the adhesive or bonding material to the resin plate is weak and the resin plate becomes easily detached.


There is described an optical radiation sensor device for detecting radiation in a radiation field. The device comprises a sensor element capable of detecting and responding to incident radiation from the radiation field and a radiation window interposed between the sensor element and the radiation field. The radiation window comprises a non-circular (preferably square) shaped radiation transparent opening. The optical radiation sensor device can be used in a so-called dynamic manner while mitigating or obviating the detection errors resulting from the use of a circular-shaped attenuating aperture and/or angular (even minor) misalignment of the sensor device with respect to the array of radiation sources when multiple such circular-shaped attenuating apertures are used.

1. Field of the Invention
Generally, the present invention relates to an optical radiation sensor system.
2. Description of the Prior Art
Optical radiation sensors are known and find widespread use in a number of applications. One of the principal applications of optical radiation sensors is in the field of ultraviolet radiation fluid disinfection systems.
It is known that the irradiation of water with ultraviolet light will disinfect the water by inactivation of microorganisms in the water, provided the irradiance and exposure duration are above a minimum "dose" level (often measured in units of microwatt seconds per square centimetre). Ultraviolet water disinfection units such as those commercially available from Trojan Technologies Inc. under the tradenames Trojan UV Max™ and Trojan UV Swift™, employ this principle to disinfect water for human consumption. Generally, water to be disinfected passes through a pressurized stainless steel cylinder which is flooded with ultraviolet radiation. Large scale municipal waste water treatment equipment such as that commercially available from Trojan Technologies Inc. under the trade-names UV3000™ and UV4000™, employ the same principle to disinfect waste water. Generally, the practical applications of these treatment systems relates to submersion of a treatment module or system in an open channel wherein the wastewater is exposed to radiation as it flows past the lamps. For further discussion of fluid disinfection systems employing ultraviolet radiation, see any one of the following:                U.S. Pat. No. 4,482,809,        U.S. Pat. No. 4,872,980,        U.S. Pat. No. 5,006,244,        U.S. Pat. No. 5,418,370,        U.S. Pat. No. 5,471,063,        U.S. Pat. No. 5,504,335,        U.S. Pat. No. 5,539,210, and        U.S. Pat. No. 5,590,390 (Re.36,896).
In many applications, it is desirable to monitor the level of ultraviolet radiation present within the water under treatment. In this way, it is possible to assess, on a continuous or semi-continuous basis, the level of ultraviolet radiation, and thus the overall effectiveness and efficiency of the disinfection or treatment process. The information so-obtained may be used to control lamp output to a desired level and/or determined when it would be desirable to clean the exterior of the protective sleeves typically used to contain the radiation lamp(s).
It is known in the art to monitor the ultraviolet radiation level by deploying one or more sensor devices near the operating lamps in specific locations and orientations which are remote from the operating lamps. These sensor devices may be photodiodes, photoresistors or other devices that respond to the impingement of the particular radiation wavelength or range of radiation wavelengths of interest by producing a repeatable signal level (e.g., in volts or amperes) on output leads.
Conventional optical radiation sensors, by design or orientation, normally sense the output of only one lamp, typically one lamp which is adjacent to the sensor. If it is desirable to sense the radiation output of a number of lamps, it is possible to use an optical radiation sensor for each lamp. A problem with this approach is that the use of multiple sensors introduces uncertainties since there can be no assurance that the sensors are identical in their response. Specifically, vagaries in sensor materials can lead to vagaries in the signals which are sent by the sensors leading to a potential for false information being conveyed to the user of the system.
U.S. Pat. No. 6,512,234 [Sasges et al. (Sasges)] teaches an optical radiation sensor system which allows determination of lamp output information for a single lamp in an array of lamps. An advantage of the Sasges system is that a single sensor device can be moved with respect to the radiation field to allow determination of the dose delivered to the fluid (i.e., in place of the multiple sensors conventionally required as discussed above). More specifically, the optical radiation sensor taught by Sasges allows for on-line determination of ultraviolet (UV) transmittance of the fluid being treated in a UV radiation lamp array.
While optical radiation sensor taught by Sasges is a significant advance in the art, there is room for improvement. Specifically, the field of view of conventional sensor devices (e.g., photodiodes, photoresistors, etc.) is relatively large thereby making it possible for the sensor device to detect in a simultaneous manner the output of more than one lamp. This can be problematic if the object is to determine lamp output information for a single radiation source (e.g., elongate lamp) in an array of radiation sources (e.g., elongate lamps).
One solution to this problem is to restrict the field of view of the sensor device so that the sensor device can "see" only one lamp at any particular point in time. Restricting the field of view of the sensor device to one particular lamp can be accomplished by interposing an appropriately sized circular-shaped aperture between the sensor device and the array of radiation sources (e.g., elongate lamps). As will be described in more detail below, interposition of a circular-shaped attenuating aperture between a sensor device and an array of radiation sources (e.g., elongate lamps) can create a further problem. Specifically, as the particular radiation source (e.g., elongate lamp) and circular-shaped attenuating aperture are moved with respect to one another (typically, the latter will be moved with respect to the former), the area of the lamp "seen" by the sensor device changes. This change in area results in unwanted changes to the radiation intensity detected by the sensor device.
Further, restriction of the field of view of the sensor device so that the sensor device can only "see" one particular radiation source (e.g., elongate lamp) may be accomplished by interposing multiple decreasingly-sized, circular-shaped attenuating apertures between the sensor device and the array of radiation sources (e.g., elongate lamps). The use of such multiple apertures in this manner can result in the intensity of the radiation detected by the sensor device varying sharply as a function of the angular position of the sensor. In the result, any angular (even minor) misalignment of the sensor device with respect to the array of radiation sources will result in an unwanted significant change in detected intensity.
These problems can cause significant errors in detection of radiation intensity from the array of lamps, thereby undermining the reliability of the radiation sensor system.
Accordingly, it would be desirable to have a radiation sensor system which could be used in a dynamic application such as the Sasges sensor system referred to above while obviating or mitigating the detection errors referred to above resulting from the use of a circular-shaped attenuating aperture and/or angular (even minor) misalignment of the sensor device with respect to the array of radiation sources when multiple such circular-shaped attenuating apertures are utilized.

Optical radiation sensor system having a radiation window with a non-circular opening


A clutch device for a magnetic recording/reproducing apparatus for transmitting power for a tape conveying regardless of the quantity of tape wound around a reel, including a rotating  central shaft installed on a main chassis, a drive pulley connected to the rotating  central shaft, and having a cylindrical pulley holder portion, said drive pulley being rotated by receiving power from a driving source, an up/down gear having a cylindrical gear holder unit with the outer diameter thereof being smaller than the inner diameter of the pulley holder portion and ascendable/descendable along the rotatable  central shaft, and a clutch spring placed between the inner surface of the pulley holder portion and the outer surface of the gear holder unit for selectively transmitting power with a certain torque from the driving pulley to the up/down gear in accordance with the rotational direction of the driving pulley.

1. Field of the Invention
The present invention relates to a magnetic recording/reproducing apparatus, and in particular to a clutch device for a magnetic recording/reproducing apparatus which is capable of transmitting power for regularly conveying a tape, regardless of the quantity of the tape, wound around a reel.
2. Description of the Prior Art
FIG. 1 illustrates a tape path conveying structure of a general magnetic recording/reproducing apparatus.
As shown in FIG. 1, a supplying reel driving body 1 and a winding reel driving body 21 are installed to drive a supplying reel (not shown) and a winding reel (not shown) of a tape cassette (not shown) at one side of a main chassis (C).
A plurality of posts and guide rollers are provided on the main chassis (C) to guide the path of a tape (T) released from a tape cassette.
A tension post 3 for controlling the tensile force of the travelling tape (T) is installed on a tension arm 4.
The tension arm 4 is rotated at a predetermined angle according to the tension of the tape (T) on the main chassis (C) centering around a shaft pin 2, on which the tension arm 4 is elastically supported by a spring 5.
The tape (T) having passed the tension post 3 is guided by a guide post 6 and transmitted to a full width erasing head 7.
The full width erasing head 7 removes, in advance, a signal which has been recorded on the tape in a recording mode.
An inertia roller is installed at a position past the full width erasing head 7 to guide the path of the tape (T).
Next, the tape (T) is guided by guide posts 10 and 11 of the supplying and winding side which are moved along loading paths formed at both sides of a rotational head drum 9.
The guide posts 10 and 11 draw the tape (T) from the inside of the tape cassette, a position indicated by a dotted line as shown in FIG. 1, so as to be wound and traveled.
A supplying slant post 12 and a winding slant post 13 are provided next to the guide posts 10 and 11 and in the direction of the rotational head drum 9, so as to guide the conveyance of the tape (T).
The guide posts 10 and 11 and the slant posts 12 and 13 are installed on respective supplying and winding slant bases 14 and 15 and moved along the loading path.
As shown in FIG. 1, the rotational head drum 9, on which the tape (T) is wound and conveyed, is provided with a rotational head (not shown) for reading a signal recorded on the tape (T) or for recording a signal.
The tape (T) passes the rotational head drum 9 and the slant post 13 and the guide post 11 of the winding side and then passes the audio control head 16. The audio control head 16 deletes, records and reproduces an audio signal, and records and reproduces a control signal.
A guide post 17 is provided on the main chassis (C), adjacent to the audio control head 16 for controlling the traveling height of the tape (T).
A capstan shaft 18 for providing a traveling force to the tape (T) is installed at a position past the guide post 17. The capstan shaft 18 is an output shaft of a capstan motor (not shown) installed at the opposite face of the main chassis (C), and the traveling direction of the tape (T) is determined by the rotational direction of the capstan motor.
A pinch, roller 19 is selectively installed to tightly engage the capstan shaft 18 to provide a force for pulling the tape (T).
A winding post 20 is provided adjacent to the location of the pinch roller 19 and the capstan shaft 18. A winding arm (not shown) is installed and moved at the winding post 20.
Between the supplying reel driving body 1 and the winding reel driving body 21, a clutch assembly 22 is installed to drive the supply reel or the winding reel at a certain torque, regardless of the amount of tape (T) wound on the supplying reel or the winding reel, upon receipt of a driving force received from the capstan motor.
An idler gear 24 is installed at a front end of an idler arm 25 which is coaxially installed with the clutch assembly 22. The idler gear 24 is adopted to selectively engage either the supply reel driving body 1 or the winding reel driving body 21 for transferring a driving force thereto upon receipt of the driving force from the clutch assembly 22.
A tension brake 27 is wound on the supplying reel driving body 1 with both of its ends fixed to the tension arm 4. The tension brake 27 controls the rotational speed of the supplying reel driving body 1 according to the operation of the tension arm 4, thereby controlling the tension in the tape (T).
The construction of the clutch assembly 22 will be described in detail with reference to accompanying FIGS. 2 and 3.
As depicted in FIGS. 2 and 3, a central shaft 30 is installed on the main chassis C. A driving pulley 32d is installed so as to rotate centering around the central shaft 30. A belt 31 which receives power from the capstan motor is wound around the driving pulley 32d for transferring the rotational force of the capstan motor. A cylindrical clutch holder 34 is installed on the driving pulley 32.
A an up/down gear 36 is installed on the central shaft 30 on the same axis as the driving pulley 32d. The up/down gear 36 transmits the power from the capstan motor by selectively engaging the idler gear 24. Clutch springs 18, 18′ are installed to the up/down gear 36. The clutch springs 18, 18′ are wound around the outer circumferential surface of the cylindrical clutch holder 34. Herein, the lower spring 18 and the upper spring 18′ are wound in the opposite directions.
According to the rotational direction of the driving pulley 32d, for example, when the lower spring 18 is locked and the upper spring 18′ rubs against the surface of the clutch holder 34, a slip occurs. Accordingly, the movement of the tape (T) can be performed with a regular torque regardless of the quantity of the tape (T) wound around the reel.
In the meantime, a first gear portion 37 and a second gear portion 37′ are formed on the up/down gear 36, the first and the second gear portions 37, 37′ reducing and transmitting power by respectively and selectively engaging with gear portions of the idler gear 24.
The idler gear 24 is rotatably installed on the front end portion of the idler arm 25, centering around the central shaft 30, each gear portion (not shown) selectively engaging the first and the second gear portions 37, 37′ of the up/down gear 36. The idler gear 24 transmits the power of the capstan motor to the supplying reel and the winding reel by selectively engaging with the supply reel body 1 and the winding reel body 21.
However, the above-mentioned conventional magnetic recording/reproducing apparatus has the following problems.
The clutch springs 18, 18′ are selectively used for conveying the tape (T) with a regular tension, regardless of the quantity of tape (T) wound around the supply reel and the winding reel in accordance with a traveling direction of the tape (T).
In this use of clutch springs 18, 18′, production costs are increased due to the large amount of construction parts. In addition, the operation efficiency of the assembly process is reduced.

Clutch device for magnetic recording/reproducing apparatus


An enhanced police Doppler direction sensing radar detects possibly dangerous traffic conditions during certain vehicle maneuvers such as U-turns and returns to travel after roadside stops. By monitoring a host or primary vehicle speed, speed transitions, transmission state (e.g. gear selection), and the closing vehicle position, range and speed, a number of selectable conditions are detected, resulting in an alert indication to a primary vehicle operator. User preferences and thresholds allow the traffic alert function to be customized according to a primary vehicle operator's desire to suppress alerts in situations which the user does not deem dangerous. The traffic alert function may be automatically triggered under certain detected conditions, or manually initiated when the primary vehicle operator intends to make a driving maneuver.

1. Field of the Invention
This invention pertains to technologies for alerting a vehicle operator potentially hazardous traffic conditions prior to or during certain common driving maneuvers, such as interception U-turns, and pulling into moving traffic from a roadside.
2. Description of the Related Art
There are many types of vehicles which, during the routine course of their operation, are exposed to hazardous traffic conditions. Police cruisers and highway patrol vehicles often must re-enter moving traffic from a roadway shoulder after detaining another vehicle, or when intercepting a vehicle for speeding or another violation. Law enforcement vehicles operating on divided highways and boulevards often make U-turns to intercept a vehicle traveling in the opposing lanes, or to respond to a dispatch call.
However, law enforcement vehicles are by no means the only type of vehicle which routinely must operate in hazardous traffic conditions. For example, another emergency vehicle such as an ambulance or fire truck may also have to return to the roadway from a stopped position on the shoulder (e.g. after completing a call to an injury, wreck, or fire), or may have to make a U-turn to respond to a fire call or medical emergency.
Non-emergency vehicles also may have to make similar maneuvers, such as a construction or street maintenance vehicle, or a utility vehicle (e.g. telephone, electrical, water, sewage or natural gas service truck or van, or school bus). When completing a job or when attempting to arrive at a place for a job near or on a roadway, these types of non-emergency vehicles may be exposed to the same traffic hazards as a police vehicle, ambulance, or fire truck.
Therefore, the following description of certain hazardous situations applies equally well to all of these types of vehicles, and not just to police and highway patrol vehicles. For the remainder of this disclosure, we utilize the term "primary vehicle" to refer to any vehicle which is subjected to a potentially hazardous traffic condition, such as a police or trooper vehicle, or alternatively another emergency or non-emergency vehicle as previously described. Additionally, we employ the term "secondary vehicle" as a vehicle which may be involved in a particular scenario, the position and condition of which the operator of the primary vehicle is aware, such as a vehicle a patrolman has detained alongside a road, or a vehicle which an ambulance or fire truck is servicing. Further, we will refer to other vehicles which pose a potential danger to the primary vehicle as a "closing vehicle", such as a vehicle which is moving in a lane of traffic in which the primary vehicle is entering, and especially of which the operator of the primary vehicle may not be aware.
Police cruisers and highway patrol vehicles are generally supplied with several types of equipment, including an enhanced engine, suspension, and braking systems, as well as voice and data communication equipment. Such vehicles are also equipped with a variety of rotating beacons, strobe lights, and LED warning indicators, which, when used separately or in conjunction with a siren, can provide warning to other motorists of the patrol vehicle's status and position. Many law enforcement vehicles are also equipped with radar guns which can determine the speed of a target vehicle in traffic, mainly for the purposes of enforcing roadway speed limits. While these types of devices are useful in many applications of law enforcement, they provide inadequate safety to the officers operating the patrol vehicle in certain scenarios.
For example, in one common law enforcement scenario (10) as shown in FIG. 1, a trooper vehicle T is traveling in a first direction at an initial position (14) on a lane (12) of a divided highway, wherein the divided highway also has a median (13) and an opposing traffic lane (11).
Initially, the trooper may be measuring the speeds of vehicles in the opposing traffic lane (11), using a police radar unit, such as determining the speed of vehicle A in an initial position (15) in front of the trooper vehicle T in its initial position (14). At this point, the police radar unit has a line-of-sight (17) from the trooper vehicle T to the vehicle A.
When the trooper decides to intercept vehicle A, he must make a U-turn maneuver (18) through the median (13), falling into a pursuit position (14′) traveling in the opposing lane (11) behind vehicle A, which has now moved to position A (15′).
However, if another vehicle B is also traveling (16) in the opposing lane (11) at the time of the trooper's U-turn maneuver (18), there may be a danger of a collision with the trooper's vehicle. Vehicle B may not be initially visible when the trooper turns due to poor roadway lighting, inclement weather, or another visual impediment. As the trooper must slow his speed during the U-turn, and regain highway speed following the U-turn, vehicle B may be closing on the trooper vehicle at a considerably faster speed. If the trooper is operating the emergency lights (e.g. strobes, beacons, etc.) or the siren, the operator of vehicle B may be alerted to the danger of collision with the trooper, but the trooper is provided no warning of the potential collision.
In this particular scenario, the trooper vehicle T represents a primary vehicle, the intercepted vehicle A represents a secondary vehicle, and the vehicle B with which a collision danger exists is the closing vehicle. In alternate versions of this scenario, the primary vehicle may be a fire truck, ambulance, utility van, school bus or maintenance truck. Even though there may not be an intercepted vehicle in such a variation of this scenario, there certainly can be a closing vehicle which presents a collision danger when the primary vehicle is making a U-turn.
In another common law enforcement scenario (20) as illustrated by FIG. 2, a trooper vehicle T (24) is initially stopped (24) alongside (21) a roadway (22), sometimes with a detained vehicle A, which is also stopped (25). Alternatively, the trooper vehicle T may not be accompanied by a detained vehicle A, such as the case when a trooper is "speed trapping" or investigating a situation to the side of the road.
As the trooper's transaction with the detained vehicle is completed, or when the trooper decides to return to patrol, he executes a driving maneuver (23) to return to the roadway (22) by pulling into the closest lane of traffic, such as by driving into position (24′). However, there may be another vehicle B traveling (26) in this same lane, approaching the trooper's position (24′). As the trooper is in transition from being stopped to achieving highway speed, the speed difference between the other-vehicle B and the trooper's vehicle T may be great, thereby increasing the danger of a collision. As with the previously described scenario, the trooper's vehicle's emergency lights, if engaged, may provide some warning to the operator of the other vehicle B, but do not warn the trooper of the impending danger.
In this second scenario, the trooper vehicle T again represents a primary vehicle, the detained vehicle, if any, represents a secondary vehicle, and the vehicle with which a collision potential exists represents the closing vehicle. In other scenarios such as this, a fire truck, ambulance, utility van, or maintenance truck may represent the primary vehicle.
Therefore, there is a need in the art for a system and method which provides detection of such possibly dangerous traffic conditions, and which provides an alerting function to a vehicle operator.


A planar waveguide and a process for making a planar waveguide is disclosed. The waveguide has a layer of dope host material formed on a substrate. The host material is a trivalent material such as a metal fluoride, wherein the metal is selected from the Group III B metals and the lanthanide series rare earth metals of the Mendeleevian Periodic Table. The dopant is a rare earth metal such as erbium. The waveguide has an emission spectrum with a bandwidth of about 60 nm for amplification of an optical signal at a wavelength of about 1.51 .mu.m to about 1.57 .mu.m. The waveguide is made by forming the layer of doped host material on a substrate. The film is formed by evaporating materials from two separate sources, one source for the dopant material and a separate source for the host material and forming a film of the evaporated materials on a substrate.

Considerable recent research has involved the development of optical amplifiers useful in optical communications. Typically, these amplifiers involve a waveguide formed in a glassy material (a material that has no long-range ordering and is characterized by an absence of Bragg peaks in X-ray diffraction and/or a glass transition observed in differential scanning calorimetry) with a rare earth dopant present in the waveguide core and with a region of lower refractive index surrounding the core. Generally, the glassy host material does not substantially affect the emission spectrum of the dopant, and the rare earth dopant material is chosen to have a spectral emission line corresponding to a wavelength at which optical communication is to be performed. For example, most long-haul optical communication is performed either at 1.3 .mu.m or 1.55 .mu.m. Optical devices that amplify signals at 1.3 .mu.m are described in U.S. Pat. No. 5,140,658 to Sunshine et al.
Optical amplifiers at 1.55 .mu.m have been demonstrated and are described in U.S. Pat. No. 5,119,460 to Bruce et al. These amplifiers involve a waveguide fiber having erbium, that emits at 1.52 to 1.56 .mu.m, present in the core at concentrations typically in the range 10 to 1000 parts per million. During operation of the amplifier, optical power at a wavelength 0.975 or 1.48 .mu.m is introduced into the waveguide core along with a signal at the 1.55 .mu.m wavelength. The optical power induces a transition in the erbium that populates a state, the .sup.4 I.sub.13/2 state, capable of stimulated emission around 1.55 .mu.m, and the signal induces this transition from the populated state. Thus, the output from the amplifier involves a signal at 1.55 .mu.m that has an intensity approaching that of the combined power and signal inputs. In his manner, an optical signal is amplified, in contrast to electrical amplification involving conversion of the optical signal to an electrical signal, followed by electrical amplification and another conversion back to an optical signal.
The concentration of the dopant affects the efficiency of the amplifier. Since the properties of the amplifier depend upon the absolute number of dopant atoms in the host material, the dopant concentration that is necessary for adequate performance depends upon the length of the device. For example, the dopant concentration in fiber amplifiers is much less than the dopant concentration in planar optical amplifiers, because fiber amplifiers are much longer than planar optical amplifiers. However, high dopant concentrations lead to concentration quenching of the luminescence from the dopant. If such quenching occurs, the amplifier gain is reduced and the amplifier performance is consequently degraded. Therefore, planar optical amplifiers that amplify signals at 1.55 .mu.m and that overcome the problems associated with high dopant concentration, and a process for making such planar optical waveguides, are sought.

Planar waveguide and a process for its fabrication


An operation of calibrating the object using a reference reader is performed, the calibration operation including an operation of placing the reference reader at various distances away from the object that correspond to various values of a parameter within the object that is representative of the intensity of the signal received by the object, and, for each distance, an operation of determining an internal phase-shift compensation in the object with respect to a nominal internal phase shift, making it possible to obtain a load modulation amplitude that is higher, in terms of absolute value, than a threshold, and an operation of storing a lookup table of the various values of the parameter and the corresponding internal phase-shift compensations.

Near-field communication, better known to those skilled in the art under the name NFC, is a wireless connectivity technology that allows communication over a short distance, for example 10 cm, between electronic devices, such as for example contactless chip cards or mobile telephones in card-emulation mode, and readers.
NFC technology is particularly suitable for connecting any type of user device and allows fast and easy communication.
A contactless object is an object that is capable of exchanging information via an antenna with another contactless object, for example a reader, in accordance with a contactless communication protocol.
An NFC object, which is a contactless object, is an object that is compatible with NFC technology.
NFC technology is an open technological platform that has been standardized in the ISO/IEC 18092 and ISO/IEC 21481 standards, but incorporates numerous standards that already exist, such as for example the Type A and Type B protocols defined in the ISO-14443 standard, which may be communication protocols able to be used in NFC technology.
Mention may also be made of the FeliCA protocol, also known as "NFC-F technology", which is standardized in the standard JIS.X.6319-4.
Besides its conventional telephonic function, a cellular mobile telephone may be used (if it is provided with specific means) to exchange information with another contactless device, for example a contactless reader, by using a contactless communication protocol that is usable in NFC technology.
This allows information to be exchanged between the contactless reader and secure elements located in the mobile telephone. Numerous applications are thus possible, such as mobile ticketing for public transport (the mobile telephone acting as a transport ticket) or mobile payment (the mobile telephone acting as a payment card).
During a transmission of information between a reader and an object in card- or ticket-emulation mode, the reader generates a magnetic field via its antenna, which is generally a sinusoidal wave at 13.56 MHz in the standards that are conventionally used. The strength of the magnetic field is between 0.5 and 7.5 amps/meter RMS (root mean square).
Two modes of operation are then possible, a passive mode or an active mode.
In the passive mode, only the reader generates the magnetic field and the object, in card- or ticket-emulation mode, is then passive and always acts as the target.
More specifically, the antenna of the object emulating the ticket or the card modulates the field generated by the reader.
This modulation is performed by modifying the load connected to the terminals of the antenna of the object.
By modifying the load at the terminals of the antenna of the object, the output impedance of the antenna of the reader changes due to the magnetic coupling between the two antennas. This results in a change in the amplitudes and/or the phases of the voltages and currents that are present in the antennas of the reader and of the object.
Thus, in this way, the information to be transmitted from the object to the reader is transmitted, by load modulation, to the antenna currents of the reader.
The load variation performed in the load modulation is reflected in an amplitude modulation and/or phase modulation of the signal (voltage or current) at the antenna of the reader. A copy of the antenna current is generated and injected into the reception chain of the reader, where this current is demodulated and processed to extract the transmitted information.
In the active mode of operation, the reader and the object in card-emulation mode both generate an electromagnetic field. Generally, this operating mode is used when the object is provided with its own power source, for example a battery, as is the case with a cellular mobile telephone, which is then in card-emulation mode.
Each of the NFC devices transmits data using a modulation scheme, typically an ASK (amplitude-shift-keying) amplitude-modulation scheme.
In this case too, the modulation is reflected by a load modification, and reference is then made to communication through active load modulation.
In comparison with a passive communication mode, greater operating distances are obtained, which may range as far as 20 cm depending on the protocol that is used.
Moreover, the use of active load modulation makes it possible to use small antennas.
However, this type of communication by active load modulation presents other problems.
It is desirable, when communicating by active load modulation, for the signal transmitted by the device in card-emulation mode to be in phase, or in phase opposition, with the signal received from the reader to have, at the reader and hence also at the device in card-emulation mode, a modulation amplitude that is as large as possible in terms of absolute value.
A phase adjustment is generally performed on the device in card-emulation mode during the development of the device in a known environment.
However, this restriction of obtaining a modulation amplitude that is as large as possible in terms of absolute value leads to interoperability problems with certain readers.
Specifically, contactless-reader infrastructure is not updated often, in particular in the transport sector, and the object in card-emulation mode must be able to operate with old readers of limited performance, such as those with only envelope-detection reception architecture, different from the architectures having two channels, I and Q, in phase quadrature.
Examples of such envelope-detector readers may implement the FeliCa protocol.
However, the inventors have observed that the distance between such envelope-detector readers and the object in card-emulation mode influences the coupling effect, in particular when this distance is small, for example smaller than 50 mm, which results in a mismatch in the reader-object system, and hence introduces a phase shift between the signal received by the reader and the signal transmitted by the object or vice versa.
There is therefore a need for this phase shift to be decreased as much as is possible or to be eliminated entirely.

Method for compensating for a phase shift between the signal emitted by an object and that received from a reader equipped with an envelope detector and corresponding object