A thin film ferroelectric varactor device comprising a substrate layer, a ferroelectric layer structure and an electrode structure is presented. The ferroelectric layer structure comprises a number of ferroelectric layers and a number of intermediate buffer layers arranged in an alternating manner. At least a first and a second layer of the ferroelectric layers have different Curie temperatures, i.e. the dielectric constant of the first ferroelectric layer has a maximum at a temperature which is different from the temperature at which the dielectric constant of the second ferroelectric layer has a maximum.

The present invention relates to the field of electrically tunable devices e.g. for microwave (radio frequency) circuits. Particularly it relates to a thin film ferroelectric varactor device, use of such a device in microwave (or millimeter wave) circuits and to a method of producing such a device.
Various tunable devices for use in microwave and millimeter wave devices have been proposed in the past. A varactor is a variable capacitance device in which the capacitance depends on a voltage applied thereto. Varactors are known to be used in RF tuning applications among others due to the fact that the capacitance variations of the varactor caused by an applied voltage has corresponding effects on frequency tuning.
Varactors based on semiconductors are known. However, such devices are disadvantageous in many aspects. They suffer e.g. from a low tunability (low dynamic range) at microwave frequencies, i.e. above 10-20 GHz, and the microwave losses are also high. Due to the inherent properties of semiconductor materials such varactors are susceptible to overheating and burnout if forward biased or reverse biased with an excessive applied voltage. Semicondutor PN junction devices have a depletion region which is subjected to high electric field stress, and as a consequence thereof, such devices may break down as the applied voltage is varied. Still further, semiconductor materials have dielectric constants between about 10-15, i.e. low dielectric constants which limits the capacitance and this is very disadvantageous for a plurality of applications.
Microelectromechanical varactors are also known. As opposed to semiconductor varactors they have a high dynamic range, or a high tunability and low microwave losses but the tuning speed is limited to tens of microseconds. In addition thereto they are sensitive to mechanical vibrations, they have a short lifetime and they are also not reliable.
Varactors based on ferroelectric materials or non-linear dielectrics are also known, e.g. from U.S. Pat. No. 5,472,935. The main disadvantage of the varactors disclosed in the above mentioned document, as well as other tunable microwave devices based on (bulk) ferroelectrics, is that the parameters are extremely temperature dependent which is related to the inherent temperature dependence of the ferroelectric materials. This is illustrated in FIG. 1A, FIG. 1B which show the extreme temperature dependence close to the maximum of the dielectric constant of typcial ferroelectric materials, Barium Titanate (BaTiO3, BTO) and Strontium Titanate (SrTiO3, STO). The dependence of the dielectric constant on an applied electrical DC field (the tunability) is also stronger close to the maximum of the dielectric constant whereas away from the maximum of the dielectric constant, the tunability is low. STO for example is not tunable at room temperature at a reasonably low applied electric field (E less than 100 kV/cm). This means that capacitors based on STO are not tunable at about room temperature (i.e. they are actually no varactors). This means that a high temperature stability only can be achieved in combination with a low tunability.
In addition thereto a transition layer is formed in the surface of the ferroelectric material at the interface between the electrodes of metal, e.g. gold, and the ferroelectric material in the varactor. The internal electric field of this layer will reduce the dielectric constant of the ferroelectric material and as a consequence thereof it also reduces the sensitivity to the applied external DC fields. In other words, the tunability of the varactor is reduced.
Ferroelectric varactors based on bulk material suffer among others from the drawback that the thickness of such devices limits the total capacitive effect.
It has been found advantageous to use thin ferroelectric films for the production of tunable capacitors since the dielectric constant of the ferroelectric films is tunable by variation of a voltage applied to the film. At high frequencies such films intrinsically show comparatively low losses.
U.S. Pat, No. 5,640,042 shows a simple ferroelectric varactor comprising a plurality of thin film layers. A carrier substrate layer is provided on which a metallic conductive layer is deposited. The thin film ferroelectric is in turn deposited on the metallic conductive layer and a plurality of longitudinally spaced metallic conductive means are disposed on the thin film ferroelectric. The carrier substrate layer, the metallic conductive layer and the thin film ferroelectric layer may have matching lattices to form a matched crystal structure. However, even if higher capacitance values than for example in semiconductor varactors can be obtained resulting in a higher tunability, such devices do not work satisfactorily for a plurality of implementations, e.g. because the temperature stability is not good enough and the extent to which such a device can be tuned is not sufficient.
What is needed is therefore an improved varactor device. More particularly a varactor device is needed which has a high dynamic range (a large range of tunability) and at the same time shows a high temperature independence, i.e. which shows a high degree of temperature stability. Particularly a ferroelectric varactor device is needed which is reliable, has a long lifetime and which do not suffer from mechanical stresses or vibrations or similar. Still further a varactor device is needed for which the tuning speed is high. The tuning speed can be defined as dC/dt, i.e. the time (t) derivative of the capacitance (C) and shows how fast the capacitance can be tuned. Further a ferroelectric varactor device is needed which is easy to fabricate and which moreover is not expensive to fabricate. Further yet a varactor device is needed which is suitable for a large number of applications, particularly for microwave or millimeter wave applications or even more particularly for microwave radio frequency applications. Particularly a varactor device is needed which has a high tunability (high dynamic range) and which is temperature independent in a given temperature interval.
A method of producing such a varactor device, fulfilling one or more of the above mentioned objects, is also needed which method particularly is easy to implement. A method of operating a tunable ferroelectric varactor device as referred to above is also needed.
Therefore a thin film ferroelectric varactor device comprising a substrate layer, a ferroelectric layer structure and an electrode structure is provided wherein the ferroelectric layer structure comprises a number of ferroelectric layers and a number of intermediate buffer layers arranged in an alternating manner. At least a first and a second of said ferroelectric layers, between which an intermediate buffer layer, which may be dielectric, is arranged, have different Curie temperatures. The Curie temperature is specifically defined as a temperature characterizing the temperature dependence of the dielectric constant. Specifically it is the temperature for which the dielectric constant has a maximum. According to the invention, different Curie temperatures for the respective ferroelectric layers is provided through giving ferroelectric layers a different chemical composition, or by chemically isolating the ferroelectric layers from one another, such that different Curie temperatures are provided. The content of at least one element of the elemental composition of the respective layer is different in the at least two layers. (Specially the content of an element may be zero in one of the layers.)
Advantageously at least some of the layers of the varactor device have lattice matched crystal structures. Even more particularly all layers, i.e. the layers of the ferroelectric layer structure, the electrode structure and the substrate layer, have lattice matched crystal structures.
In a preferred implementation the layers, particularly the intermediate buffer layers and the ferroelectric layers and the substrate layer comprise single crystalline films (epitaxial films).
In a preferred implementation the ferroelectric layers comprise a ceramic material. Particularly at least one element or component of the ceramic material is provided in a different fraction for a number of the layers or particularly for all layers, such that at least adjacent ferroelectric layers, wherein adjacent is taken to mean that ferroelectric layers between which an intermediate buffer layer, particularly a dielectric buffer layer, is provided, contain different fractions of said element(s).
In an advantageous implementation the ceramic materials comprise perovskite oxides or solid solutions thereof, ABCO3, wherein A for example is one of Ba, Na; B is anyone of e.g. Sr, Kr; C is is one of Tc, Nb etc. In a particular implementation the ferroelectric layers comprise BaxSr1-xTiO3. At least for the above mentioned first and second layers the Barium (Ba) content is different, thus for a first and a second layer the elemental composition is Bax1Sr1-x1TiO3 and Bax2Sr1-x2TiO3 respectively resulting in different Curie temperatures. Of course there may be more than two layers having different xi values or specifically different Barium-content. Particularly is for each ferroelectric layer i, 0xe2x89xa6xixe2x89xa61.
In an alternative implementation the at least two layers comprise NaxiK1-xiNbO3 wherein xi is different for, at least two xe2x80x9cadjacentxe2x80x9d ferroelectric layers. In a particularly advantageous implementation the intermediate buffer layers comprise dielectric films. The dielectric films between different ferroelectric layers may have the same elemental composition or different elemental compositions.
In a particular implementation, at least one of the dielectric films has an elemental composition of MgO, LaAlO3, CeO2 or a material with similar properties. If the ferroelectric structure is such that there are more than one intermediate buffer layer, e.g. if there are more than two ferroelectric layers requiring an intermediate buffer layer between them, or, if an intermediate layer also is provided between a ferroelectric layer and the substrate layer, each dielectric buffer layer may be of the same elemental composition but it does not have to. In a particularly advantageous implementation at least one of the dielectric intermediate buffer layers has an elemental composition of WO3.
According to different implementations one dielectric layer has an elemental composition of WO3 whereas one or more other layers comprise MgO or similar; alternatively all of the layers comprise WO3. In still another implementation, at least one of the intermediate buffer layers comprises a multilayer structure comprising a number of sublayers, with at least one sublayer with an elemental composition of MgO or similar, as referred to above, and at least one sublayer with an elemental composition of WO3. The substrate layer may have an elemental composition of MgO, LaAlO3 or a material with similar properties whereas the electrode structure may comprise longitudinally arranged electrodes defining a gap between them. The electrodes may for example comprise gold (Au), copper (Cu), silver (Ag) or similar but they may also comprise superconductors or particularly high temperature superconductors, of YBCO (YBaCuO) or TBCCO (TlBaCaCuO).
In a preferred implementation the ferroelectric layers have a thickness smaller than, or equal to, 1 xcexcm. The intermediate buffer layers, which particularly are dielectric, may have a thickness of 100 nm or less. They may be also be somewhat thicker in case they consist of a combination of WO3 and MgO (also than they may however be as thin as referred to above) or similar, or if they comprise a multilayer structure. In another implementation, the ferroelectric layer structure comprises a ferroelectric nanostructure with ultra thin ferroelectric layers having a thickness substantially smaller than or equal to 100 nm. A buffer layer may be provided adjacent to the electrode structure, i.e. between the electrodes and a ferroelectric layer or an intermediate buffer layer (a dielectric layer). Such buffer layer may for example consist of thin metallic Mg films.
The ferroelectric device may particularly comprise a ferroelectric layer structure comprising three or more ferroelectric layers wherein between each pair of ferroelectric layers a preferably dielectric, intermediate buffer layer is provided. An intermediate buffer layer may also be provided between the substrate layer and the ferroelectric layer to be deposited on the substrate layer.
Particularly the temperature dependence of the capacitance of the varactor can be controlled by selection of the Curie temperatures/the xi values in the elemental compositions of the respective ferroelectric layers, i.e. the content of at least one element of the elemental composition.
A thin film ferroelectric varactor device comprising a substrate layer, a ferroelectric layer structure and an electrode structure is provided in which the ferroelectric layer structure comprises a number of ferroelectric layers and a number of intermediate buffer layers, which preferably are dielectric, wherein the ferroelectric layers and the dielectric layers are arranged in an alternating manner such that ferroelectric layers between which an intermediate buffer layer is provided, are chemically separated from each other. At least some of the ferroelectric layers have a different elemental composition. Particularly the ferroelectric layers comprise ceramic materials, such as perovskite oxides or solid solutions of the type AxiB1-xiCO3 wherein xi is different for at least some subsequent ferroelectric layers between which an intermediate buffer layer is provided. Particularly, for each layer i, 0xe2x89xa6xixe2x89xa61. Particularly the ferroelectric layers i, wherein i, . . . , N; N being the number of ferroelectric layers of the structure, comprise Baxi Sri-xi TiO3 or Naxi K1-xi NbO3. Particularly all layers of the varactor device have matching crystal structures and the Curie temperatures of the respective ferroelectric layers are different, wherein the respective Curie temperatures are given by the selection of each xi, and the selection is done so as to assure that the maximum values of the dielectric constants of the respective layers are different. Particularly the temperature dependence of the capacitance of the varactor can be controlled. Particularly the Ba-content/the Na-content is different for each respective layer (having as a consequence that also the Sr/K content is different).
According to the invention the varactor devices as discussed above may with advantage be used in microwave (radio frequency) circuits, such as tunable resonators, filters, phase shifters, delay lines, mixers, harmonic generators or similar.
A method of producing a thin film ferroelectric varactor device comprising a substrate layer structure, a ferroelectric layer structure and an electrode structure is also given which includes the steps of; providing a ferroelectric layer structure on the substrate layer structure, including the steps of; providing an intermediate, preferably dielectric, buffer layer between each of a number of ferroelectric layers; for at least two ferroelectric layers (i;i+1), selecting different contents (xi,x(i+1)) of a first component of the elemental compositions of the layers; selecting the contents (xi,x(i+1)) such that the dielectric constants of different layers will have different Curie temperatures. The varactor may then be operated between the Curie emperatures of the two ferroelectric layers.

Electrically tunable device and a method relating thereto


Methods are disclosed using Trospium Chloride, an antimuscarinic smooth muscle relaxant, for the treatment of urinary incontinence, and other disorders, while avoiding the concomitant liability of adverse side effects associated with other antimuscarinic drugs.

Trospium has been shown to reduce bladder hyperactivity in patients suffering from urinary incontinence and exerts spasmolytic effects on the bladder by inhibiting the effects of acetylcholine on smooth muscle. Trospium has selectivity for muscarinic receptors over nicotinic receptors and as a result, no blocking effects are observed at skeletal neuromuscular junctions. Active metabolites of trospium exert antimuscarinic activities that may account for part of the therapeutic activity of trospium.
In particular, compounds within the class of antimuscarinic drugs for urinary incontinence, including terodiline, tolterodine and oxybutynin, cause severe cardiac electrophysiological side effects. These adverse side effects are associated with prolonged QT interval and include but are not limited to ventricular fibrillation and cardiac arrhythmias, such as torsades de pointes. This is the same type of potentially lethal cardiac side effects that led to the withdrawal of several medications from the market; examples of drugs that have been withdrawn of that reason are the antihistamine drug terfenadine, the antihistamine drug astemizole, the prokinetic drug cisapride and the incontinence drug terodiline that is mentioned above.
No known reference teaches or enables the methods of the present invention comprising administering trospium to a human while avoiding said adverse cardiac side effects; nor do the published references alone or in combination suggest these methods.

Methods for treating urinary incontinence and other disorders using trospium


Provided is an arthritis treatment method and an arthritis treatment system which can be effective for the short-term attainment of a pain relief effect. An arthritis treatment method includes an instrument introducing step of causing at least one instrument having a tubular shape to communicate with a lesion area in which crystal-induced arthritis occurs, and a treatment step of removing a causative agent of the crystal-induced arthritis from the lesion area by perfusion and discharge of a lavage fluid through the instrument.

In recent years, gout, which is a typical example of crystal-induced arthritis, has been increasing year by year, and even the number of conscious patients has reached the level of one million.
Gout is developed by causative agents, such as uric acid crystals depositing in the joint and chemical substances released by phagocytosis by white blood cells or the like of those crystals, and causes severe pain, swelling, or fever.
Treatment for gout typically includes the administration of a drug, but the perfusion of a drug into a lesion area as in a treatment for cancer discussed in, for example, the treatment described in Japanese Patent Application No. JP-T-2009-529992, the entire contents of which are hereby incorporated herein by reference for all that it teaches and for all purposes, has not been established.

Methods and system for treating arthritis


A mixing vessel (10) for containing a liquid, comprises a chamber having a lower chamber portion and an upper chamber portion wider than the lower portion, gas inlet means (14) for supplying gas to the lower portion and means for redirecting rising gas (24), such that, in use, rising gas in the form of bubbles, initially rises substantially vertically and is redirected in a substantially horizontal direction by the means for redirecting rising gas.

Many academic and industrial processes utilise cell culture to generate cells or in the production of biomaterials or compounds of interest.
In other processes, such as ultra filtration or the mixing of biological solutions or the dissolution of solids into aqueous solutions, it is necessary to provide fast, effective and yet gentle mixing of the liquid medium.
In cell culture, an aliquot of cells is placed in a vessel of some description, provided with the nutrients required for the growth of the cells, and is either supplied with oxygen or grown anaerobically in the absence of oxygen. After a period of time to allow production and growth of new cells, the cultured cells are typically removed from a vessel and harvested or separated from the medium.
In processes upstream and/or downstream from the culture process, it is often important to mix cells, media or other materials, to prevent them from settling in a storage tank or from forming precipitates. In these instances, it is essential to keep the medium contained within the vessel from settling and so it is advantageous for the medium in the vessel to be kept in constant motion.
Since the first use of aerobic cell culture systems, there have been a series of physical constraints that workers in the field have attempted to address. One of the primary constraints is how to achieve good aeration of the culture without incurring (excessive) damage to the cells being grown and at the same time to achieve a homogenous suspension, or mixing, of cells and to avoid the formation of unstirred areas or "dead spots".
One arrangement widely used in cell culture employs sparging air in the bottom of a vessel so as to cause recirculation of the culture medium. This further improves aeration without the need for physical agitation and has the added benefit of mixing the cell culture without the need for expensive stirring, rolling or rocking devices. The type of culture system that uses an internal air-powered aeration system is often described as a pressure-cycle fermenter or airlift fermenter.
In a pressure-cycle fermenter, the aerated stream of gas and solution that results from sparging the vessel at its base, has a lower density than that of the undisturbed solution and therefore rises. This stream is often referred to as the "riser". The solution that is drawn in to take its place forms a stream, often referred to the "downcomer". Circulation within the cell culture can therefore be achieved simply by aerating the culture as described in GB2002417A, U.S. Pat. No. 5,660,977 and GB1383432A.
However this method often suffers from having regions of 'dead zones' in which the culture media is not effectively mixed. To overcome this problem, many inventions have sought to separate the riser and the downcomer through the use of a physical barrier. GB2002417A, U.S. Pat. No. 5,660,977 and GB1383432A describe a variety of configurations in which this is achieved. Generally, the riser is directed to the surface of the culture solution through a tube that is arranged vertically and runs from the bottom, up to just below the surface of the culture medium. The riser moves upwards, and is replaced by the downcomer which circulates the solution. In other arrangements, the downcomer can be an external tube.
Other arrangements, such as that disclosed in U.S. Pat. No. 4,649,117, do not require the use of a separation device to divide the riser and the downcomer. In this arrangement, the upper surface of the culture medium is considerably wider than at the base, which contains the sparger. While this will generate the required riser and downcomer, it can be observed in such systems that there are often areas of the culture that are mixed less well than others to give "dead spots" or "flat spots". To compensate for this, the operator will often increase the aeration rate to achieve better mixing. This is a disadvantage because increased sparging will also give rise to the requirement for more gas, which increases process cost, and greater foaming. Foaming must be controlled, as for certain mammalian cell culture systems, there is a direct correlation between increased sparge rate and increased cell mortality. This trend can be entirely eliminated by contolling foaming through the addition of antifoaming agents. One skilled in the art will recognize that a better solution to this problem is to keep foaming to a minimum so as to reduce the cost of the antifoam addition or the possible interference of the antifoam reagents in downstream processes.
JP61202680A teaches that cells attached to a carrier (generally a bead with an activated surface to which cells adhere) can be kept in suspension in a chamber that is separated from the media feed and mixing apparatus by a porous plate that allows the passage of media and gas but does not allow the carriers, with their adherent cells, from passing through the porous separator plate. This is an advantage because the beads are kept separate from the stirring means, which tend to fragment the beads and therefore loose their ability to bind cells when damaged. However, the porous plate cannot separate cells that are grown in free suspension, which would therefore pass through the porous plate. Therefore JP61202680A is limited in the type of cells which can be successfully grown, and prevent it from being applied in the growth of cells such as insect cells, yeast and bacteria, all of which are grown in suspension and not on surfaces.
The costs of assembling and maintaining such fermentation and cell culture systems in a production environment has always been high and steps have therefore been taken to develop disposable systems made from low-cost plastics. EP 0 343 885 discloses a system that utilises the pressure-cycle principle in a plastics bag, in which the riser and downcomer are separated by an intervening plastics sheet, to promote the pressure-cycle effect. The plastics vessel is sparged using a tube inserted from the top of the plastics vessel and the air is dispersed into small air bubbles through the use of a metallic frit assembly. While the use of a separating sheet may in theory provide better circulation due to the pressure-cycle process, overall, it reduces the amount of mixing that takes place and inevitably causes "dead zones" as mentioned above. A very similar arrangement of a reusable plastics bag with a downward-pointing sparging pipe was described in US 2002/0110915 A1 in which no separator was employed.
Many of the commercially available cell culture systems have relied on the use of some form of impeller, under which the aerating gas is delivered into the cell culture. The speed at which the impeller is rotated, its shape and surface area all have the potential to improve the rate of oxygen transfer. A good summary of the art of impeller design can be found in U.S. Pat. No. 6,250,797. One of the major disadvantages of agitation with impeller blades of any shape is that they cause shear stress and often lead to excessive foaming of the cell culture. Considerable heat can also be generated which must be removed, further increasing costs for production. These issues are to be avoided with non-bacterial cells as this results in lower biomass production and poor cell viability.
Other methods of improving oxygen transfer rates without inducing shear stress as a result of deploying impellers have been developed. For example, flexible plastics bags provide a number of opportunities for alternative means of gentle agitation. Bags can be manipulated through the use of external pressure applied mechanically (U.S. Pat. No. 3,819,158), by moving liquid from one bag chamber to another (EP 972 506 A), from rocking the bag back-and-forth (U.S. Pat. No. 6,190,913) or by moving one portion of the bag using mechanical means with pneumatic collars or cuffs (US 2005/0063250 A). In these cases, it is still often necessary to enrich the airflow into the air space above the culture in order to achieve sufficient rates of oxygen transfer and such systems are only used to grow cells with a low requirement for oxygen.
These issues are not confined to cell culture, but also apply in the preparation of solutions and solids that are used in bio production of all types, or in the isolation of the bio product from the cell culture medium. The use of a disposable modules in such operations significantly reduces the cost of cleaning and revalidation of the plant's components compared with modules made from glass and stainless steel. However, the provision of effective mixing has remained a major challenge for many of the reasons already discussed. Agitation must be achieved either by recirculating a liquid at great velocity, which itself causes problems, or through the inclusion of a disposable propeller driven directly through a sealed bearing system (which must be disposable) or through the use of a magnetically coupled and disposable propeller. Both generate heat, excessive shear forces and are expensive.

This patent is subject to a terminal disclaimer.


An electronic device including a wireless communication processor configured to wirelessly communicate with at least one other electronic device; a display; and a controller configured to execute a web application of a web browser installed on the electronic device, display an execution screen of the web application on the display, extract a web code of the web application associated with the execution screen, and transmit the extracted web code to the at least one other electronic device through the wireless communication unit such that screen information related to the execution screen is displayed on a display of the at least one other electronic device using the web code without executing a corresponding web application on the at least one other electronic device.

Electronic devices are devices which are portable and have at least one of voice and telephone call functions, information input and/or output functions, a data storage function and the like. As it becomes multifunctional, the mobile terminal can be allowed to capture still images or moving images, play music or video files, play games, receive broadcast and the like, so as to be implemented as an integrated multimedia player.
Many efforts are undergoing to support and enhance various functions as such multimedia player in view of hardware or software improvements. For example, a user interface environment is provided in order for users to easily and conveniently retrieve or select functions.
With the increase in the functions of the electronic devices, the electronic devices are capable of extending functions through communication with other electronic devices.

Electronic device and communication system having the same


A vehicle traveling control apparatus includes a setter, a detector, and a determiner. The setter sets a lane-change route through which an own vehicle change lanes from a current target route to an adjacent lane. The detector detects a road surface pattern by irregularities on a road to which a lane change is to be made. The determiner determines whether the own vehicle interferes with the road surface pattern, and instructs correction of the set lane-change route based on a result of the determination. When there is not the interference, the determiner permits the lane change through the lane-change route. When there is the interference, the determiner instructs the setter to correct the lane-change route. The determiner permits the lane change through the corrected lane-change route when there is not the interference on the corrected lane-change route, and prohibits or cancels the lane change when there is still the interference.

The technology relates to a vehicle traveling control apparatus that controls traveling of an own vehicle.
In vehicles such as automobiles, traveling controls such as a lane-keeping control and a follow-up traveling control have been known. The lane-keeping control recognizes a traveling environment around an own vehicle and allows for keeping of a traveling position of the own vehicle at a middle position of a lane. The follow-up traveling control also recognizes the traveling environment and allows for traveling while following a preceding vehicle ahead of the own vehicle. The recognition of the traveling environment of the own vehicle may be performed with, for example, a camera and a radar unit each mounted on the own vehicle.
In such a vehicle traveling control, a technique has been proposed that assists or automatically performs movement of the own vehicle to an adjacent lane by changing a traveling route of the own vehicle. The assistance or the automatic performance of the movement of the own vehicle to the adjacent lane is to be made at a time when the own vehicle overtakes a preceding vehicle traveling at a speed lower than that of the own vehicle, or at a time when a driver operates a direction indicator, or a winker, with an intention of changing lanes.
For example, Japanese Unexamined Patent Application Publication No. 2009-294943 discloses a technique of assisting the lane change. The disclosed technique of assisting the lane change is performed by: determining a vehicle traveling circumstance of a target lane into which the own vehicle is to proceed; determining whether there is any other vehicle that may possibly proceed into the target lane from a position other than the traveling lane along which the own vehicle travels; and setting guide information based on the vehicle in the target lane and the vehicle at a position other than the target lane.


A UV curable ink-jet recording apparatus includes: a recording medium transporting unit; an ink-jet head; and a UV irradiating unit, wherein the apparatus includes a light capturing portion between the UV irradiating unit and the ink-jet head, at least a part of the light capturing portion as seen in a longitudinal section taken vertically along a direction of transporting the recording medium has an opened wedge shape having no base side and comprising: a side vertical to the recording medium; and an oblique side which is in contact with a top of the vertical side, and which extends obliquely downward, the vertical side is located on the side of the ink-jet head, and the oblique side downward extends from the top toward the UV irradiating unit.

An ink-jet apparatus in which an ink that can be cured by an active energy ray such as a UV ray (ultraviolet ray) or an electron beam is ejected onto a recording medium with using an ink-jet head, and the ink is cured by active-ray irradiation to form an image has features such as that it is environmentally friendly, and that it can obtain a high-resolution image which can be recorded at a high speed on various recording media, and which hardly bleeds. Particularly, development of an apparatus which uses a UV curable ink is advancing from the viewpoints of easy handling of a light source, compactness, and the like. By taking the advantage of the high-speed fixing property, a so-called single-pass ink-jet apparatus has been proposed in which a web-like recording medium that can be transported at a high speed is used, a head having a width that allows recording to be performed over the whole width of the recording medium is placed so as to be opposed to the recording medium in a state where the head is fixed, and recording is completed simply by causing the recording medium to pass under the head one time. In the case where color printing is performed by using such a single-pass ink-jet apparatus, stationary heads the number of which is equal to that of colors are arranged in the direction of transporting the recording medium. In order to prevent different colors from being mixed with each other in this case, an apparatus in which light irradiating means is placed downstream of each of the heads of the respective colors is disclosed (see JP-A-2004-314586).
On the other hand, in an apparatus having a high productivity, when a web-like recording medium is transported at a high speed, transport wobbling of a base member occurs, and the image quality is reduced. Therefore, an image forming portion must be shortened, and the ink-jet head and the UV irradiating unit are placed in proximity to each other. In this case, there is a possibility that a UV ray which is emitted from the light source, or that which is emitted from the light source and reflected from the surface of the recording medium enters a nozzle face, and inks on the nozzle face and in the vicinities of ejection ports react with UV light to be thickened or cured, thereby causing nozzle clogging or an ejection failure. In order to reduce the quantity of a UV ray entering a nozzle face, an apparatus in which a light trap for capturing a UV ray is disposed between a recording head and a UV irradiating unit is disclosed (see JP-A-2004-167717).
The light trap disclosed in JP-A-2004-167917 is employed in an apparatus of the carriage type. FIG. 5 shows an ink-jet apparatus in which this concept is applied to the single-pass ink-jet system, and which is a premise of the invention. Although the invention will be described with respect to an example of a single-pass ink-jet apparatus, the invention is not restricted to this.
In FIG. 5, 40 denotes the single-pass ink-jet apparatus. In the single-pass ink-jet apparatus 40, the recording medium S is taken out from a recording medium roll 41 which is wound in a roll. First, during when the recording medium S is transported under a full-line ink-jet head 43Y for Y (yellow) color in which many ink-jet nozzles are arranged in the width direction of the recording medium S, a Y-color ink is ejected onto the recording medium S no as to form a desired image. Immediately after the ejection, the recording medium S is passed under a UV irradiation lamp 44. During the passage, the Y-color ink which is a UV curable ink, and which is ejected onto the recording medium S is exposed to UV light to be subjected to semi-curing.
Next, during when the recording medium S is transported under a full-line ink-jet head 43M for M (magenta) color in which many ink-jet nozzles are arranged in the width direction of the recording medium S, an M-color UV curable ink is ejected onto the recording medium S so as to form a desired image. Immediately after the ejection, the recording medium S is passed under a similar UV irradiation lamp 44. During the passage, the M-color ink which is ejected onto the recording medium S is exposed to UV light to be subjected to semi-curing.
Then, during when the recording medium S is transported under a full-line ink-jet head 43C for C (cyan) color in which many ink-jet nozzles are arranged in the width direction of the recording medium S, a C-color UV curable ink is ejected onto the recording medium S so as to form a desired image. Immediately after the ejection, the recording medium S is passed under a similar UV irradiation lamp 44. During the passage, the C-color ink which is ejected onto the recording medium S is exposed to UV light to be subjected to semi-curing.
Finally, during when the recording medium S is transported under a full-line ink-jet head 43B for B (black) color in which many ink-jet nozzles are arranged in the width direction (the direction perpendicular to the plane of the figure) of the recording medium S, a B-color UV curable ink is ejected onto the recording medium S so as to form a desired image. Immediately after the ejection, the recording medium S is passed under a metal halide lamp 45 which is higher in light intensity than the above UV irradiation lamps 44. During the passage, the four-color inks are exposed to UV light to be fixed, thereby completing recording using the four-color inks.
For the purpose of improving the productivity, enhancements of the sensitivity of an ink and the energy or a UV irradiation tamp are attempted.
On the other hand, on the lower face of each of the ink-jet heads 43, the ink is easily cured by leakage light from the UV irradiation lamps 44. In order to allow the ink-jet head 43 to stably perform the ink jet ejection for a long term, in the apparatus of FIG. 5, a light capturing portion 47 is interposed between the ink-jet head 43 and the UV irradiation lamp 44, so that leakage light from the UV irradiation lamp 44 does not reach the ink-jet head 43.


The invention provides a drainage bag (e.g. an ostomy bag or the like) for receiving bodily waste, the drainage bag comprising a water-impermeable outer bag; a water-impermeable inner bag enclosed therein; and an orifice to enable bodily waste to be received by the inner bag; the outer and inner bags being detachably secured together in the region of the orifice. The outer and inner bags are preferably detachably secured together by means of frangible or peelable connection or linkage therebetween.

This invention relates to ostomy bags and like drainage bags, and in particular to bags for which the contents can be disposed of more readily and hygienically by flushing down a W.C.
Ostomy bags for receiving bodily waste from colostomy or ileostomy patients are well known and a major problem with such bags is that it can be difficult to dispose of the used bag in a convenient and hygienic manner.
Often, the contents of used bags are removed by cutting an edge of the bag and depositing the contents into a W.C. for flushing away, leaving the soiled bag for separate disposal, e.g. by incineration or by wrapping and placing in a waste bin. Disposal of a used bag and its contents in this way is clearly unhygienic and unpleasant for the user and, in recognition of this problem, various proposals have been made for ostomy bags which can be flushed down a W.C.:- see for example GB-A-2083762, EP-A-0388924, GB-A-2227668, and GB-A-2193925.
However the ostomy bags currently available suffer from certain drawbacks. Firstly, due to the buoyancy and relative bulk of the bags, it is often difficult to flush them down the W.C. Secondly, in order to ensure that the bag is sufficiently strong and waterproof to withstand the rigours of use, materials have been used which do not decompose readily, if at all, in the sewerage system, thereby giving rise to a pollution problem.


A method of manufacturing a rubber mixture includes the step of mixing at a first temperature in a batchwise operation a base mixture of rubber and non-reactive additives in a ram mixer. In a subsequent step the base mixture is removed from the ram mixer and formed to a strand. The strand is cooled to a temperature at which the strand is still warm. The warm strand is then fed to a ramless mixer and reactive additives are added. In a batchwise operation the base mixture and the reactive additives are mixed at a second temperature that is lower than the first temperature in order to form a finished rubber mixture. Preferably, cooling and feeding of the strand are performed simultaneously.

The present invention relates to a method for manufacturing rubber mixtures in which in a first step in a ram mixer a base mixture is produced from rubber and non-reactive additives in a batchwise manner and in which in a second step the base mixture, without being stored intermediately, is finished in a ramless mixer in a batchwise manner by adding reactive additives at a reduced temperature.
In the known methods of the aforementioned kind the cooling within the ramless mixer is in general sufficient to cool the base mixture below the scorch time limit and furthermore to mix homogeneously the reactive additives within the working cycle time. The working cycle of the base mixer, on the one hand, and of the finishing mixture, on the other hand, are to be adjusted relative to one another.
With especially large mixing units and/or for very viscous or rapidly curing mixtures, for example, adhesive mixtures for metals, the difficulty may result that the cooling and finishing mixing in comparison to the mixing of the base mixture requires more time. Under these conditions an economical operation of a batch-type operation is no longer possible.
These disadvantages are to be eliminated with the present invention. Accordingly, the present invention has the object to provide a method that ensures an adaptation of the working cycle during base mixing and finishing-mixing even when the aforementioned special conditions are present.

Method and apparatus for manufacturing rubber mixtures


The invention relates to synthetic liver-specific promoters and expression constructs for producing polypeptides and functional nucleic acids in the liver of a subject. The invention further relates to Factor VIII proteins containing modifications in the amino acid sequence of the Factor VIII protein, as well as nucleic acid constructs encoding the Factor VIII proteins and methods of using these compositions to treat a bleeding disorder.

Factor VIII (FVIII) plays a critical role in the coagulation cascade by accelerating the conversion of factor X to factor Xa. Deficiency in FVIII activity is responsible for the bleeding disorder hemophilia A. The current treatment for hemophilia A is intravenous infusion of plasma-derived or recombinant FVIII protein. Despite this treatment being effective in controlling bleeding episodes, the requirement for frequent infusion, owing to the short half-life of FVIII (8-12 hours), makes it inherently costly. Gene therapy has emerged as an attractive strategy for the eventual cure of this disease. However, the progress in delivering FVIII gene using one of the most promising viral vectors, adeno-associated virus (AAV), has lagged behind the progress in delivering coagulation factor IX because of the large size of the FVIII coding sequence approaching the packaging capacity of AAV.
The present invention overcomes shortcomings in the art by providing a short synthetic liver-specific promoter and expression construct suitable for use in AAV vectors. The invention further provides FVIII proteins comprising additional glycosylation sites with amino acid sequence modifications and methods of their use in treating bleeding disorders.

Optimized human clotting factor VIII gene expression cassettes and their use

The University of North Carolina at Chapel Hill


A clutch assembly, including: a secondary piston assembly; a primary piston including a portion located radially outward of the secondary piston assembly; a first chamber at least partially formed by a first side of the primary piston; a second chamber at least partially formed by the secondary piston assembly and a second side of the primary piston; and a check valve connecting the first and second chambers. For a first force applied by fluid in the first chamber: the primary piston remains axially stationary; the fluid flows from the first chamber into the second chamber; and the secondary piston assembly displaces in a first axial direction to contact a clutch pack. For an increase of the first force to a second force: fluid flow between the first and second chambers is blocked by the check valve; and the primary piston and the secondary piston assembly displace in the first axial direction to close the clutch pack.

It is known to use a hydraulic piston to close a clutch pack in a clutch for an automatic transmission. It is desirable to minimize the time required to close such a clutch by reducing the travel needed for the piston to engage and compress the clutch pack. The travel can be reduced by minimizing spacing between clutch plates in the clutch pack. However, minimizing the spacing increases the viscous drag between the clutch plates, which increases losses for the transmission and increases fuel consumption for a vehicle using the transmission. Also, the greater the travel required for the piston, the greater the amount of fluid needed to displace the piston. Increasing the amount of fluid needed increases the work required of a pump for the fluid, further increases losses in the transmission.
U.S. Pat. No. 6,162,147 describes a single piston for a clutch assembly with two pressure chambers for displacing the piston. One of the chambers is pressurized more quickly than the other chamber. U.S. Pat. No. 3,915,274 describes a dual piston arrangement for a clutch assembly with dual pressure chambers and a common fluid input line. The two chambers are independently connected to the input line. That is, there is no direct flow of fluid between the two chambers. An outer piston is initially displaced by an increase in pressure in one chamber to contact move the inner piston into contact with a clutch pack. The movement of the inner piston due to contact with the outer piston increases a volume of the other chamber and pressure is increased in the other chamber in a timed relation to the pressure increase in the outer chamber. As pressure in the other chamber increases, the inner piston displaces independently of the outer piston to close the clutch pack.

Two stage piston for faster clutch apply


A toy launcher apparatus of a soft foam dart where the dart is loaded onto a spike in a firing chamber by a pusher panel that presses against the nose of the dart. The apparatus includes a dart magazine with a feed mechanism. The pusher panel is followed by a barrier sleeve that prevents the next uppermost dart in the magazine, which is being biased upward by the feed mechanism, from causing either the uppermost dart or the second uppermost dart to distort and cause a jam. The barrier sleeve also prevents the magazine from being loaded through a top opening until the uppermost dart in the firing chamber is launched. Near the end of a cocking cycle, the pusher panel, which is connected to a cam follower tab that engages a cam member, moves away from a launch path of the dart in the firing chamber.

Toy launcher apparatus are well known. For example, U.S. Pat. No. 4,843,751 issued to Ferri in 1989 entitled "Toy Firearm Operated By Compress Air, With Magazine In An Element In The Guise Of A Trigger," purport to disclose a toy firearm operated by compressed air and a spring, and the firearm includes a retractable magazine. To cock the firearm a user pulls on a trigger 24/sliding element 16 against a spring 18 and a spring 7. A resilient rocker detent 32 engages a detent 12/rod 10 to displace the rod 10 and a piston 5, and to compress the spring 7. Toward the end of the cocking action the rear end of the detent 32 comes into contact with an inclined surface 14C of a slide housing 14 and the detent 32 is displaced (against a spring 34) until the detent 32 releases the detent 12. At this point the spring 7 propels the piston 5 forward and the compressed air fires the projectile P1.
Another example is U.S. Pat. No. 9,389,042 issued in 2016 to Clayton and entitled "Projectile Launcher." The Clayton patent purports to disclose a projectile launcher having a movable slide 12, which draws a plunger 21 rearwards by engagement of a slide flange 19 and a plunger flange 21a. As the plunger moves rearward a spring 24 is compressed and at an end of the slide movement a trigger latch 23c engages an opening 21c. In one variation, projectiles may be loaded from above the frame 111, FIG. 9.
The earlier patents disclose devices that are complicated and expensive, and neither of the two patents discloses an element pushing a projectile rearward into a barrel nor act as a barrier to prevent jamming from below and above.

Projectile launcher apparatus with magazine


A pressure actuated current interrupt device particularly useful for prismatic electrochemical cells has a cup-shaped member (12, 12', 12", 12'", 12.sup.IV, 12.sup.V, 12.sup.VI) mounted on the cover of the cell and arranged to protrude into the interior of the cell. The cup-shaped member can be formed either as a separate member or as a portion of a layer of a composite cover. The cup-shaped member has a side wall (12b) in which stress is created by pressure generated in the cell which acts on the generally flat end wall (12a) of the cup-shaped member. A selected amount of pressure causes the side wall to catastrophically collapse with the configuration of the cup-shaped member being inverted to permanently break the electric current path with a cover mounted terminal. A composite cover (8.sup.iv, 8.sup.v) includes a membrane layer in which the cup-shaped member is formed and which can also include a pressure vent (12g).

Electrochemical cells, especially high energy density cells such as those in which lithium is an active material, are subject to leakage or rupture as a result of various abusive treatment, which in turn, can cause damage to a device which is powered by the cell or to the surrounding environment. Such cells are sealed to prevent egress of electrolyte solvent and ingress of moisture from the exterior environment. When a cell is overcharged, self-heating occurs during the charging procedure. Examples of abusive treatment include charging at too rapid a rate, overcharging above a specified maximum voltage or discharging below a specified minimum cell voltage which can lead to an increase in temperature and/or pressure. In the case of cells utilizing lithium, should the temperature exceed a certain point an exothermic reaction begins which leads to overheating and causes a build-up in pressure which may result in expulsion of electrolyte from the cell.
It is known for commercially available cylindrical lithium ion electrochemical cells to incorporate a pressure driven current interrupt device to terminate current flow under adverse charge or discharge conditions. Typically, a thin metallic diaphragm, e.g., formed of aluminum, mounted in a header of the cell and exposed to pressure generated in the cell is attached to a pressure plate at the central axis, as by laser or ultrasonic welding, with an electrical insulator sandwiched therebetween. As pressure increases stress is created at the welded interface with the weld joint fracturing at a selected pressure range allowing the diaphragm to translate away from the plate to permanently open the electric circuit and terminate current flow. In some designs, the diaphragm is formed with a reduced thickness portion, e.g., a C-shaped groove extending along the peripheral edge of the diaphragm so that the diaphragm ruptures at a calibrated predetermined pressure to allow controlled venting of pressurized electrolyte. A current interrupt device of this type is shown in U.S. Pat. No. 5,691,073.
The above described end cap and current interrupt device assembly can be used conveniently in cylindrical electrochemical cells typically having diameters of 17 mm or more. However, as cell size is reduced the available membrane surface used to drive the pressure current interrupt device is reduced so that with prismatic cells having a thickness of only 10 mm, 8 mm or 6 mm, for example, the diameter of the working portion of the diaphragm is too small to provide sufficient translation to fracture the welded joint with the pressure plate so that a different operational mechanism is needed to provide the current interrupt function. As a result of the size limitations of such prismatic cells, the prevalent header related safety feature currently in commercial use is a pressure vent which allows controlled release of pressurized electrolyte in order to prevent cell explosion.

Current interrupt apparatus particularly adapted for use with prismatic electrochemical cells


A vehicle computer is programmed to: detect a portable computing device communicatively coupled to the vehicle computer. The vehicle computer is further programmed to control at least one vehicle operation based at least in part on the presence of the portable device, the at least one vehicle operation including at least one of control of steering, propulsion, and brakes.

Self-driving (also referred to as autonomous) vehicles can allow vehicle operators to focus attention on things other than vehicle operations. However, it is typically desirable for an operator of an autonomous vehicle to be able to resume control of some or all vehicle operations, e.g., steering, throttling, and/or braking control, upon short notice, e.g., in a matter of seconds or less. However, there is a risk that if the vehicle operator is engaged in a non-driving task, e.g., a movie, game, or video conference, the operator might intentionally or unintentionally ignore a takeover request issued by a vehicle computer.

Vehicle control based on connectivity of a portable device


The invention provides a design and an integrated circuit having a substantially uniform density and electrical characteristics between parts of the IC that are angled at 45 degrees relative to one another. In particular, the invention provides fill tiling patterns oriented substantially uniformly to electrical structures of either orthogonal or 45 degree angle orientation.

1. Technical Field
The present invention relates generally to fill tiling patterns for an integrated circuit.
2. Background Art
Current integrated circuit (IC) manufacturing techniques benefit from a uniform density of wiring or conductors within a layer. For example, uniform density is required to prevent different amounts of wear across a plane during chemical mechanical polishing. To provide uniform density, various techniques for filling of empty spaces have been developed. See, for example, U. S. Pat. Nos. 5,278,105 (Eden et al.), 5,341,310 (Gould et al.) or 5,923,563 (Lavin et al.).
One challenge in providing uniform density of wiring within a plane is addressing the effect of fill tiling patterns on the electrical properties, i.e., fill tiles acting as fringe capacitance, on an adjacent wire. In particular, fill tiles add complexity to the electrical analysis of the circuit because each shape represents a floating conductor coupled by capacitors to the wire. As a result, the fill tiles change the overall capacitance between the connected wires of the circuit, and modify the electrical analysis result. Conventionally, fill tile patterning is addressed by predicting the electrical impact of the fill tiles relative to all electrically significant shapes. By mathematically accounting for the impact of the fill tiles, new capacitances between the connected circuits can be established and then fitted to modified expressions. One conventional technique for predicting the impact of fill tiles is to assume a uniform fill tile environment around shapes based on the predicted behavior of the fill tile pattern creation program. This technique is used because it takes into account the fill tile pattern without increasing the amount of computational resources required to analyze the layout compared to actually adding the fill tiles to the layout.
This uniform fill tile pattern assumption, historically, yields acceptable results because of the orthogonal nature of the wiring and the use of square fill tiles. That is, most wiring has an orthogonal layout (i.e., wires meet at right angles) and the fill tiles are oriented parallel thereto. Advancements in processing technology, however, are now making mixed non-orthogonal and orthogonal wiring patterns possible. Unfortunately, the provision of mixed orthogonal and non-orthogonal wiring with orthogonal fill tile patterns makes the fill tile environment non-uniform relative to the wiring. Accordingly, consistent assumptions about the impact on electrical properties of the fill tile patterns are no longer possible. To illustrate, FIG. 1 shows an IC including orthogonal and non-orthogonal wiring and an orthogonal fill tiling pattern throughout. In this situation, one can assume for analysis a uniform environment across much of the IC because of the orthogonal nature of the wiring and fill tiles. However, because the distance of the tiling pattern from the non-orthogonal (diagonal) wire varies along the wire's length, a number of additional parameters for each non-orthogonal wire segment must be known in order to make valid assumptions. For example, the precise length, the corresponding periodicity and angle of the fill, and the impact on the electrical properties must be ascertained for each segment of non-orthogonal wire. Consideration of all of these parameters makes analysis of the impact of the orthogonal fill tiling on the adjacent non-orthogonal wiring impracticable.
In view of the foregoing, there is a need in the art for a method for providing a substantially uniform density and electrical characteristics for an integrated circuit having mixed orthogonal and non-orthogonal electrical structure.

International Business Machines Corporation


An aperture diaphragm, configured by a plurality of diaphragm blades which are formed with generally wedge-shaped notches for defining small diaphragm apertures, is provided with a supplemental diaphragm blade coupled to one of the diaphragm blades. The supplemental diaphragm blade has a supplemental notch which is similar in shape to but shallower than the generally wedge-shaped notch of the one of the diaphragm blades so as to block up the smallest diaphragm aperture defined by the generally wedge-shaped notches of the diaphragm blades.

1. Field of the Invention
This invention relates to a diaphragm, and, more particularly, to an iris diaphragm for use with optical instruments, such as still cameras and video cameras, for controlling the amount of light.
2. Description of Related Art
Iris diaphragms for use with optical instruments, such as still cameras and video cameras, are often automatically controlled to regulate the amount of light. These diaphragms are divided into two types.
The first type of iris diaphragm has a plurality of sector-shaped diaphragm blades, to one of which a neutral density filter is secured. Although this type of iris diaphragm is adapted to close entirely, its aperture is prevented from excessively decreasing in size when it is automatically controlled. On the other hand, while the camera is not in use, the iris diaphragm is entirely closed to isolate internal elements of the camera from light.
Referring to FIG. 1, showing one of the conventional first type of iris diaphragms, sector-shaped diaphragm blades 10, 12 and 14 are partially lapped one over another so as to form a substantially circular opening, as a diaphragm aperture DP, with their inside edges. The blades are held between a stationary diaphragm ring (not shown) and a diaphragm adjusting ring 24 which are arranged coaxially and are enabled to make relative rotation. These diaphragm blades 10, 12 and 14 are, respectively, pivoted on pivot pins 10A, 12A and 14A secured to the stationary diaphragm ring. Each of the diaphragm blades 10, 12 and 14 is formed with a cam slot 10B, 12B or 14B, adjacent to its pivot pin 10A, 12A or 14A, which is directed approximately radially when the diaphragm blades 10, 12 and 14 are fully opened. The diaphragm adjusting ring 24 is provided with actuator pins 16, 18 and 20 at regular angular separations which are, respectively, received for sliding movement within the cam slots 10B, 12B and 14B of diaphragm blades 10, 12 and 14. Turning of diaphragm adjusting ring 24 causes the diaphragm blades 10, 12 and 14 to turn about pivot pins 10A, 12A or 14A to open and close the iris diaphragm. Diaphragm blade 10, which at the top, as viewed from the stationary diaphragm ring, is provided, at the middle of the inside edge, with a small piece of neutral density filter 22 adhered thereto so as to project within the opening defined by the diaphragm blades 10, 12 and 13.
Turning of the diaphragm adjusting ring 24 in the counterclockwise direction causes diaphragm blades 10, 12 and 14 to turn about pivot pins 10A, 12A and 14A, respectively, in the same direction so as to diminish the diaphragm aperture DP and finally close it entirely. On the other hand, when turning the diaphragm adjusting ring 24 in the clockwise direction, the diaphragm blades 10, 12 and 14 are forced to turn about pivot pins 10A, 12A and 14A, respectively so as to gradually open the diaphragm aperture DP.
If this iris diaphragm is automatically controlled responding to changes in the amount of light, because a distance L1 of a point of action from the pivot pin of diaphragm blade 10, 12, 14 is shorter than a distance L2 of a center of the blade from the pivot pin of diaphragm blade 10, 12, 14, operational plays between the actuator pins 16, 18 and 20 and the cam slots 10B, 12B and 14B of diaphragm blades 10, 12 and 14, respectively, are magnified. Accordingly, the iris diaphragm exhibits a diaphragm aperture of less accuracy. If high accuracy is a requirement, then a feedback control, which in turn will generally slow down a control of the aperture diaphragm, is necessary.
Referring to FIG. 2 showing another type of conventional iris diaphragm, a plurality of circular arcuate-shaped elongated diaphragm blades 30 are lapped one over another so as to form a substantially circular opening, as a diaphragm aperture, with their inside edges and held between stationary diaphragm rings 31. A diaphragm adjusting ring 32 with an adjusting projection 34 is arranged coaxially with and supported for rotation between the stationary diaphragm rings 31. These diaphragm blades 30 are, respectively, each pivoted at one end on pivot pins 30A secured to the stationary diaphragm ring 31 at regular angular intervals. Each of the diaphragm blades 30 is provided at the other end with a pin 30B. The diaphragm adjusting ring 32 is provided with actuator slots 32A at regular angular intervals. The pins 30B of diaphragm blades 30 are, respectively, received in the actuator slots 32A of diaphragm adjusting ring 32.
Turning of the diaphragm adjusting ring 32 in the counterclockwise direction causes diaphragm blades 30 to turn about pivot pins 30A in the same direction so as to open the diaphragm aperture DP. On the other hand, when turning the diaphragm adjusting ring 32 in the clockwise direction, the diaphragm blades 30 are forced to turn about pivot pins 30A so as to diminish the diaphragm aperture DP.
This type of iris diaphragm offers a decrease of operational play caused at a point of action, namely, between the actuator slot 32A and pin 30B, of the diaphragm blade 30. This is because a distance L3 between points of action of the pivot pin of a diaphragm blade 30 is longer than a distance L4 between center of blade 30 and the pivot pin 30A of a diaphragm blade 30. Consequently, the iris diaphragm offers an increase in accuracy of diaphragm aperture.
However, when the iris diaphragm is adjusted to smaller sizes of apertures, the diaphragm blades 30 interfere with one another, so as to render the iris diaphragm difficult to fully close as shown in FIG. 3. Further, it is difficult to attach a neutral density filter to one of the diaphragm blades 30.


Nerve entrapment such as Carpal Tunnel Syndrome is relieved by a surgical procedure for increasing the spatial diameter of the tunnel enclosing the nerve, which involves inserting a protected balloon catheter into the tunnel and serially inflating and deflating the catheter while moving it along the tunnel from one end to the other.

invention is directed to a surgical procedure for relieving nerve entrapment such as Carpal Tunnel Syndrome by increasing the spatial diameter of the tunnel enclosing the nerve.
Carpal Tunnel Syndrome is a common painful condition of the hand characterized by a decrease in median nerve sensibility with paresthesias of the fingers. It is the most common nerve entrapment syndrome of the upper extremity and results from compression of the median nerve in the carpal tunnel and provides nocturnal pain, clumsiness, and weakness of grasp or pinch.
The carpal canal is the area in the wrist and palm of the hand formed by the U-shaped cluster of bones of the carpus that forms the rigid hard floor and the two sides of the tunnel. Within the confines of this space are the median nerve, and the extrinsic flexor tendons of the thumb and fingers with their surrounding synovial membranes of the radial and ulna brusae. The roof of the tunnel is formed by the transverse carpal ligament on the palmar surface of the carpal bones. The ligament is attached medially to the pisiform and the hamulus of the hamate and laterally to the tuberosity of the scaphoid and the medial part of the palmar surface and ridge of the trapezium. The proximal border of the ligament is partially merged to the distal border of the palmar carpal ligament, but this is a more superficial structure and is separated from it by the ulnar artery and nerve. The transverse carpal ligament is attached to the palmar aponeurosis, which lies superficial, and contributes crossed oblique fibers to the deep surface of the aponeurosis. (Goss, Charles Mayo Ed.; Gray's Anatomy; Twenty-ninth American Edition, p 473.)
Any condition that diminishes the size of the carpal tunnel can precipatate the Carpal Tunnel Syndrome (Milford, Lee., Campbell's Operative Orthopaedics., 7th Ed: 459). Repetitive wrist and hand motions can cause thickening and hypertrophy of the transverse carpal ligament. Also, proliferation of synovium from normal wear and tear of daily activities can cause compression of the median nerve within the closed confines of the carpal tunnel. A previous fracture or dislocation of the wrist may cause bone to protrude with narrowing of the tunnel. Furthermore, systemic conditions such as pregnancy, obesity, diabetes, mellitus, thyroid dysfunction, or chronic renal failure can initiate the syndrome. Generally, the syndrome occurs most often in patients between the ages of 30 and 60 years and is five times more frequent in women than in men Milford, Lee., Campbell's Operative Orthopaedics., 7th Ed: 459). Clinical diagnosis is established by medical history, physical examination including the Phalen wrist flexion test Phelen, G. S.: The carpal tunnel syndrome: 17 years experience. J. Bone Joint Surgery., 48A:211-228, 1966) and Tinel's sign as well as the median nerve oompression test. Thenar atrophy to some degree may be evident with prolonged compression of the median nerve.
Carpal tunnel pressure measurements have been studied in symptomatic patients and such studies showed a marked increase in the mean pressure of the carpal tunnel from 32 mm with the wrist in neutral position to 99 mm with 90 degrees of flexion and 110 mm with the wrist in extension. Normal control measurements were 2.5 mm in neutral position, 31 mm in flexion, and 30 mm with wrist extension ( Gelberman, R. H., Hergenroeder, P. T., Hargens, A. R., Lundborg, G. N., and Akerson, W. H.: The carpal tunnel syndrome: as study of carpal tunnel pressures, J. Bone Joint Surg. 65-A:380, 1981).
Electromyelographic studies in classical carpal tunnel syndrome show a distal wrist latency in conduction velocity. Prolongation of the distal sensory latency above 3.5 Msec has been found to be present in 85 to 95 per cent of surgically confirmed cases (Heckler, F. R., Jabaley, M. D.: Evolving concepts of median nerve decompression in the carpal tunnel: Hand Clinics 2(4):723-726, 1986). Irreversible muscle damage is indicated by denervation potentials.
Historically, carpal tunnel syndrome has been treated nonsurgically by splinting of the affected hand and wrist, oral antiinflammatory medioation, and local steroid injection. If nonsurgical methods are unsuccessful surgical intervention is indicated.
Open surgical decompression of the carpal tunnel by division of the transverse carpal ligament was first described in 1930 by Learmonth. Open procedures generally entail a curved longitudinal incision ulnar to and parallel to the thenar crease. Taleisnik described an incision along the ulnar border of the ring finger axis (Taleisnik, J.: The palmar cutaneous branch of the median nerve and the approach to the carpal tunnel: An anatomical study; Bond Joint Surg, 55A: 1212, 1973). This incision may extended proximally to the wrist flexor crease. Angling the incision towards the ulnar aspect of the wrist helps to avoid cutting the palmar sensory cutaneous branch of the median nerve. This nerve is located in the interval between the palmaris longus and the flexor carpi radialis tendons. After division of the skin and subcutaneous tissue, the transverse carpal ligament is identified and divided along its ulnar border to avoid and to prevent injury to the median nerve or its recurrent branch.
Open surgical decompression of the median nerve is not without risks and complications (Kuschner, Stuart H, Brien, William W, et al.; Complications associated with carpal tunnel release; Orthopedic Review: April 1991; Vol XX; Number 4:346-351). Long term analysis of patients having surgical treatment for carpal tunnel syndrome have shown a failure rate as high as 19% (Kulick, Michael, I., D.D.S., M.D., et al.; Long-term analysis of patients having surgical treatment of carpal tunnel syndrome,; Jour of Hand Surg; 11A (1):59-66. 1986). A study noted in The Journal of the American Medical Association in April, 1991 found "the initial relief of open carpal tunnel surgery to be shadowed by significant scar pain and weakness in almost a third of subjects after 2 years." (Nancollas, Michael P.; Symptoms may return after carpal tunnel surgery; JAMA,; Vol 265, No 15, p 1922, April 17, 1991). Thirty percent of all patients in the study were rated with poor or fair result at an average of 5.5 years follow-up "57% of the patients in the study complained of return of some preoperative symptoms, most commonly pain, beginning an average of 2 years after surgery." (Nancollas, Michael P.; Symptoms may return after carpal tunnel surgery; JAMA,; Vol 265, No 15, p 1922, Apr. 17, 1991.) Complications include continued pain and or numbness, hypersensitive scar, loss of grip strength, joint stiffness, adherence of flexor tendons, neuroma, injury to the median nerve or its' motor branch or digital nerve injury, damage to the palmar cutaneous nerve, vascular injury, palmar hematoma, infection, and possible reflex sympathetic dystrophy.
A retrospective analysis of 40 cases of reoperation for carpal tunnel syndrome found adhesions and fibrosis around the median nerve in the carpal canal in 36 cases. (Wadstroem, J., Nigst, H.,; Reoperation for carpal tunnel syndrome: a retrospective analysis of 40 cases; Ann. Chir. Main; 5:54-58, 986.)
Hand weakness with loss of grip strength can also be a problem. Carpal tunnel release produces an average widening of the transverse carpal arch of 2.7 mm. There is a direct relationship between widening of the carpal canal and decreased grip strength. The average decrease in grip strength is 12%. (Gartsman, Gary, M., Kovach, John, C., et al.; Carpal arch alteration after carpal tunnel release; J. Hand Surg. (AM.) 11-A:372-374, May, 1986.) Computerized tomographic (CT) studies of the carpal tunnel after transsection of the transverse carpal igament have shown that if the flexor retinaculum is not intact, the flexor tendons will bowstring palmarly while the wrist and fingers are flexed together, causing weakness of grip. Some authors have recommended the use of a firm postoperative compression dressing immobilizing the wrist in slight dorsal extension for 3 weeks to prevent prolapse of the flexor tendons. (Jessurun, W, Hillen, B, et al.; Carpal tunnel release: Postoperative care: Handchirurgie 20:39-40, January, 1988.)
Because of the concern over widening of the carpal arch with subsequent decrease in grip strength, following standard carpal tunnel re1ease, Jakab and associates devised a technique employing reconstruction of the transverse carpal ligament. (Jakab, Emery, Ganos, Doreen, et al.; Carpal tunnel release: Postoperative care: Handchirurgie 20:39-40, January, 1988.) These authors stated that by reconstructing the transverse carpal ligament, the transverse carpal arch was stabilized affording protection to the median nerve and preventing potential bowstringing of the flexor tendons. By repairing the transverse carpal ligament the normal relationship of the carpal canal and its contents was restored and maintained.
Pre and post operative CT scanning of the wrist in carpal tunnel syndrome has been performed and has shown that postoperative decompression results in the regeneration of a much more flexible ligament, which allows the contents of the tunnel, to expand anteriorly. The divided transverse carpal ligament heals in a stretched or arched position allowing more room for the median nerve and flexor tendons. (Chaise, F., Roger, B.,; Pre-and post-operative CT scanning of the wrist in carpal tunnel syndrome; Rev Chir. Orthop.; 72:297-302' 1986.)
In recent years endoscopic techniques have been utilized to incise and divide the transverse carpal ligament, (Agee, John, M., et al.; Results of a study on the effectiveness of endoscopic release of the carpal tunnel; American Society for Surgery of the Hand, 45th annual meeting; Okutsu I, Ninomiya S, et al.; Endoscopic management of carpal tunnel syndrome; Arthroscopy: 7(1):11-18, 1989; Okutsu I, Ninomiya S, et al.; Measurement of pressure in the carpal canal before and after endoscopic management of carpal tunnel syndrome: J. Bone Joint Surg: 71A (5):679-683, 1989;Chow, J. D. : Endoscopic release of the carpal Iigament: A new technique for carpal tunnel syndrome: Arthroscopy: 5(1): 19-24, 1989.) Attempts have been made to decrease the size of the surgical incision with the benefit of decreasing postoperative morbidity because hand strength returns more quickIy and the hand is less tender. (Quote: John M. Agee, M.D.; Endoscopic carpal tunnel release gentler than open; Orthopedics Today: February, 1991; p.24) Refinements of endoscopic release of the carpal ligament have been evolving but complications with this procedure have been reported The complications include neuropraxia of the median and or ulnar nerve, digital nerve laceration, laceration of palmar vessels, laceration of flexor tendons, neuropraxia or laceration of the palmar cutaneous branch of the median nerve, palmar hematoma, adhesions of tendons, perineural fibrosis, bowstringing of flexor tendons with loss of grip strength, incomplete transaction of the carpal ligament with recurrence of symptoms and hypertrophic scar. (Resnick, Charles T., Miller, Brent, W.: Endoscopic carpal tunnel release using the subligamentous two-portal technique; Contemporary Orthopaedics, Vol: 22 (3), March, 1991:269-277.) A dual incision technique has been developed (Chow, James, C., Y.; Endoscopic release of the carpal ligament: A new technique for carpaI tunnel syndrome; Arthroscopy: 7(1): 19-24, 1989) with attempt to further increase the safety and efficacy of the endoscopic procedure but the potential complications of surgically transsecting the transverse carpal ligaments remain evident. A recent study was reported where endoscopic carpal tunnel release was practiced on 13 fresh-frozen cadaver hands by surgeons who had "extensive" clinical endoscopic carpal tunnel surgery experience at three Boston, Massachusetts teaching hospitals. Complete release of the transverse carpal ligament was achieved in only five of the cadaver hands. Endoscopically, the incomplete release of the ligment occurred distally, "where concern about the superficiaI palmar arch may have caused hesitation." It was found that the fat pad between the transacted edges of the transverse carpal ligament obscures the view through the endoscope and neurovascular structures may not be directly observed. (Schwartz, Jr., J. Tphomas; Symptoms may return after carpal tunnel surgery; JAMA,; Vol 265, No 15, p. 1925, Apr. 17, 1991) It was concluded that, "the recurrence rate in patients undergoing endoscopic carpal tunnel release must be scrutinized long term in light of the high incidence of incomplete sectioning of the ligament and the narrow margin of safety". (Schwartz, Jr., J. Thomas; Symptoms may return after carpal tunnel surgery; JAMA; Vol 265, No 15, p. 1925, Apr. 17, 1991).
Various patents disclose devices for inserting or placing catheters within chosen parts of the human body. U.S. Pat. No. 4,655,214 discIoses a soft inflatable introducer having a closed rounded distal tip sheath. After insertion and placement of the introducer with sheath adjacent to distal end of a catheter, the sheath is inflated and approximal end of the sheath is sealed to maintained it in expanded inflatable condition where catheter is being intubated. After the catheter has been intubated, a clamp of the sheath is opened to deflate the sheath into the introducer withdrawn. U.S. Pat. No. 4,645,491 discloses a catheter placement apparatus used in inserting a catheter to a preferred depth. The device is constructed of a surgical needle provided with a longitudinal window to which a catheter inserted in the needle can be viewed. The catheter has a colored patch of the same length as the window in the series of spaced visually distinct markings allowing the position of the catheter to be accurately located by lining the colored patch with the window and inserting the catheter until at least one mark appears in the window, to determine, the distance of the mark from the surface of the skin. U.S. Pat. No. 3,537,452 discloses a needle guard and beveled cutter for use with intravenous catheterization units. The device has a tubular body with a flat base and a longitudinally slotted top. The diameter of the tube is greater than the diameter of the needIe contained therein. U.S. Pat. No. 3,592,193 discloses a removable needle guide to be used with a flexible catheter tube in withdrawing or introducing fluids relative to a body. The needle guide has winged handles associated therewith which provides controlled insertion and removing from the body with subsequent attachment from a flexible catheter tube. U S. Pat. No. 5,011,478 discloses an introducer set including a sheath and dilator formed with a smooth external shape. The distal end of the sheath is embedded in the dilator and formed in angle oblique to the longitudinal access of the introducer set. U.S. Pat. No. 3,559,643 discloses a catheter placement unit for insertion of a catheter into a body lumen through an incised opening in the lumen wall. The unit includes a longitudinally slit sheath having a catheter therein and an advancer connected to one end of the catheter, initially and axial alignment with the sheath to close the end of the sheath.

Percutaneous carpal tunnel plasty method


The invention relates to a dual magnetoresistive head (DMR) having a narrow track-width, defined as equal to or less than 10 times the height of its MR elements, for use in reproducing signals having short wavelengths greater than 100 kiloflux changes per inch. The track width reduction to less than 10 times the MR element height introduces new parameters into the determination of the DMR signal response. In particular, the directional sense of the magnetization vectors along the longitudinal axes of the two MR elements join with the transverse bias field direction and the signal field direction in determining the head response; that is, the head's performance is now determined by its "three dimensional" characteristics, rather than the "two dimensional" characteristics as in the prior art. In the "symmetric" DMR, the longitudinal bias component in each of the DMR's magnetoresistive elements are parallel and oriented in the same direction, while in the "anti-symmetric" DMR the longitudinal bias components are parallel but are oriented in opposite directions. The symmetric DMR has an off- track response which allows it to possibly serve simultaneously as a tracking head as well as a data reproduce head, while the anti-symmetric DMR has a data signal output that can be more than twice that of the symmetric DMR.

1. Field of the Invention
This invention relates to magnetic recording, and in particular to a dual magnetoresistive head (DMR) for reproducing short wavelength, very narrow trackwidth digital data.
2. Description Relative to the Prior Art
The trend in digital disk recording systems continues in the direction of higher areal recording densities. This trend provides increased efficiency in the use of the recording medium, and contributes to the overall compactness and reduction in size of current computers. At the present time, linear recording densities of 50 kilo flux changes per inch and track densities of 2500 tracks per inch result in readily available areal densities of 125 megabits per square inch.
An important component in attaining higher areal densities has been the MR reproduce head utilized in conjunction with a inductive record head. Both shielded and unshielded single element MR heads are known in the art, and each configuration has its advantages and its limitations. However, both configurations provide advantages which include independence of output level on head/media velocity and optimization of the write and read functions of the combined inductive write/ MR read transducer.
The dual MR head (DMR) having a pair of unshielded MR elements as disclosed in U.S. Pat. No. 5,084,794 provides the additional advantages of ease of head fabrication, excellent short wavelength response, a self biasing characteristic, and freedom from MR element shorting problems present in other biased MR head configurations. U.S. Pat. No. 5,084,794 is hereby incorporated by reference.
Referring to FIG. 1, a typical DMR 10 known in the prior art consists of two magnetically, electrically and geometrically matched MR elements 12,14. In this DMR embodiment, the MR elements 12,14 are separated over substantially their entire lengths by an electrically conductive spacer 16. A sense and biasing current 22 flowing to the head 10 via leads 24,26 divides between the two MR elements 12,14 into two equal currents 28,30 because the MR elements 12,14 are identical; a small portion of the current 22 flows in the spacer 16. The DMR 10 is shown in contact with a magnetic medium 11.
The thin film MR elements 12,14 are rectangular in shape. This configuration results in the shape anisotropy of the MR film being directed along the longitudinal axis of the film, which is also the direction of its unbiased magnetization. Static bias fields generated by the flow of sense current rotate the magnetization from this axial direction, and the signals from the magnetic medium further modulate the angular position of the magnetization, changing the film resistance. The currents 28,30 flowing in the same direction in the MR elements 12,14 generate magnetic fields that result in the mutual biasing of the MR elements 12,14 because each of the MR elements, as well as being a field detection element, acts as a soft adjacent biasing layer for the other. The bias field He at element 12 due to this self-biasing mechanism, is equal in magnitude and opposite in sign to the bias field -H.sub.B at the element 14. In biasing the MR elements 12,14 the magnetic field H.sub.B rotates the magnetization of the MR element 12 in one direction, and the field -H.sub.B rotates the magnetization of the MR element 14 in the opposite direction. It will be noted that the biasing fields H.sub.B and -H.sub.B due to the sense current have essentially no longitudinal components; they solely lie along the height directions of the MR element 12,14.
The MR and DMR heads of the prior art have usually been characterized by track widths equal to or greater than 10 times the MR element height. For example, in the above referenced patent the disclosed DMR has a track width of 50 microns and an MR element height of 5 microns. This large ratio of longitudinal extension to height in the heads of the prior art means that operation of the head is essentially "two dimensional" in nature. That is, characteristics of the head operation are determined in the plane perpendicular to that of the longitudinal axis of the MR element, and neither the head sensitivity nor the signal fields from the recorded medium vary appreciably in the longitudinal direction over the active area of the MR element.
For an understanding of the operation of the narrow track width DMR for use in short wavelength signal reproduction, it is advantageous to consider the general signal response mechanism of the MR elements. There are essentially two mechanisms for generation of the MR reproduce signal; 1) direct signal field coupling, and 2) surface-field coupling plus flux propagation. The former accounts for the circumstance when the average (that is, over the MR element active volume) magnetic field emanating from the recorded medium is sufficiently large to directly induce modulation of the MR element magnetization to be observable as magnetoresistive signal. At high ( or even at moderate) linear recording densities, the fields from the medium die off extremely rapidly over distances of the order of typical element heights, and the MR response is due predominately, if not exclusively, to the second mechanism. In this case, the fields from the medium, being essentially non-negligible only at the medium's surface, enter the MR element at the head/medium interface and this surface flux is then internally propagated up into and through the remainder of the MR element. It is this second mechanism which primarily determines the response of the DMR of the present invention to high recording density signals.

Dual magnetoresistive head for reproducing very narrow track width short wavelength data


A rotational coupling device having two flanges with normally coincident axes and centers on the axes, a constant length flexible wire joining the centers, a spring compressed between the flanges and coaxial with the wire and a bellows that is rigid in torsion fixed to the flanges.

The invention concerns a translation control device usable among other things for focusing an optical instrument on a spacecraft, for example, and more generally any highly accurate rotational coupling device.
Optical instruments on board satellites, such as telescopes, for example, in some cases include focusing mechanisms in order to improve the quality of the images received. The function of such mechanisms is to optimally position one or more lenses disposed in the optical field in order to focus the light beam correctly.
The lens is to this end moved in rectilinear displacement along the optical axis of the light beam by a motorized device in practice consisting of an electrical rotating stepper motor, the output shaft of which cooperates with a lead screw type translation control system.
The lens also cooperates with a pure translation guidance system along the optical axis. The system must be highly accurate as it must avoid any misalignment of the lens relative to the optical axis, as a result of rotation and/or transverse displacement.
The motorized device controlling the axial displacement of the lens must, on the one hand, guarantee the integrity of the guidance function so as to avoid compromising the optical performance of the mechanism since it must not result in any angular or transverse offset of the optical axis. On the other hand, the motorized device must provide an adequate motor drive margin without requiring excessive onboard power, as it must not generate disturbing resisting forces or torques.
The displacement control device must, therefore, enable application to the lensholder assembly of a force F parallel to the optical axis without generating any disturbing mechanical stresses, such as forces transverse to the optical axis, tilting moments, etc.
Disturbing mechanical stresses appear immediately when there is any misalignment, even less than one degree, between the motor axis and the axis of the lead screw device. Misalignment is difficult to prevent because of manufacturing tolerances, assembly defects, temperature variations that can cause differential thermal expansion, and so on.

Highly accurate rotational coupling device and translation control device comprising same, in particular for optical instruments

Aerospatiale Societe Nationale Industrielle


A method includes modulating a laser that is coupled to a fiber; modulating the laser with a member selected from the group consisting of low frequency thermal modulation or bias modulation to broaden a laser linewidth, increase an SBS threshold and reduce an IIN; and modulating the laser with a predistorting modulation selected from the group consisting of phase modulation or amplitude modulation, the predistorting modulation being of equal magnitude but opposite phase as that produced in at least one member selected from the group consisting of the laser or the fiber as a result of the low frequency thermal modulation or bias modulation. An apparatus includes a laser; and a fiber coupled to the laser, wherein the laser is i) modulated ii) modulated with a member selected from the group consisting of low frequency thermal modulation or bias modulation to broaden a laser linewidth, increase an SBS threshold and reduce an IIN and iii) modulated with a predistorting modulation selected from the group consisting of phase modulation or amplitude modulation, the predistorting modulation being of equal magnitude but opposite phase as that produced in at least one member selected from the group consisting of the laser or the fiber as a result of the low frequency thermal modulation or bias modulation.

Field of the Invention
Embodiments of the invention relate generally to the field of optical communications. More particularly, an embodiment of the invention relates to compensation of distortion from SBS/IIN suppression modulation.
Discussion of the Related Art
Directly modulated lasers are commonly used in hybrid fiber-coax systems to transmit RF signals over long distances using optical fibers. These lasers are usually single mode and operate at wavelengths near 1310 nm or 1550 nm. The advantage of 1310 nm is most installed fiber has zero dispersion around this wavelength. Zero dispersion is important because the wavelength of directly modulated lasers fluctuates or chirps with modulation. This can lead to non-linear transmission effects if fiber dispersion is not zero.
The advantage of 1550 nm is most installed fiber has minimum loss around this wavelength. So 1550 nm can be used to transmit signals over longer distances than 1310 nm. In addition, the non-zero dispersion that most installed fiber exhibits around 1550 nm helps mitigate four wave mixing effect, allowing 1550 nm to be more easily used for wavelength division multiplexing. However, the non-zero dispersion interacts with laser chirp to produce intermodulation distortion of the transmitted signal. One way to mitigate the effects of chirp-dispersion induced distortion is to reduce the chirp of the optical source. Directly modulated optical sources with low chirp include, but are not limited to, special low chirp DFB lasers as well as external cavity lasers.
Reducing chirp too much or under-modulating the laser can lead to an increase in noise and distortion from SBS and/or IIN effects. To help compensate for this, a low frequency SBS/IIN suppression modulation can be added to the laser. This can be in the form of a bias modulation and/or a thermal modulation. A thermal modulation is preferred because it will not decrease clipping margin. However, obtaining a fast thermal modulation can be difficult. Therefore, a low frequency bias modulation may be more practical. Fortunately, a low frequency bias modulation will produce a similar effect as thermal modulation. The chirp from low frequency modulation is typically dominated by thermal effects caused by junction heating and will provide a much larger increase in laser linewidth than can be achieved for the same modulation amplitude at RF frequencies. So a significant increase in linewidth can be obtained with only a small decrease in clipping margin.
Various predistortion schemes have been proposed to compensate for intermodulation distortion caused by chirp-dispersion interaction of the transmitted RF signal. These schemes all involve compensation of only intermodulation products of the RF signal to be transmitter i.e. distortion products of the RF signal mixing with itself. The purpose of this invention is to provide means compensate for intermodulation products of the RF signal mixed with a low frequency SBS/IIN suppression signal whether it be from thermal or bias modulation of the optical source.

Compensation of distortion from SBS/IIN suppression modulation