A gas turbine engine has, in flow series, a compressor section, a combustor, and a turbine section. The gas turbine engine further has a system (i) for cooling the turbine section and (ii) for providing tip clearance control between turbine blades of the turbine section and a plurality of circumferentially distributed segments which form an annular shroud surrounding the outer tips of the turbine blades. The system includes a turbine section cooling sub-system which diverts a first cooling air flow received from the compressor section to a heat exchanger and then to the turbine section to cool components thereof. The first cooling air flow by-passes the combustor and is cooled in the heat exchanger. The turbine section cooling subsystem has a first valve arrangement which regulates the first cooling air flow. The system further includes a tip clearance control sub-system which supplies a second cooling air flow to an engine case to which the segments are mounted. The second cooling air flow regulates thermal expansion of the case and thereby controls the clearance between the segments and the outer tips. The tip clearance control sub-system has a second valve arrangement which regulates the second cooling air flow. The system further includes a closed-loop controller which issues first and second demand signals to respectively the first and the second valve arrangements. Each of the first and second demand signals are determined on the basis of: (i) a value of the first demand signal at a previous time step, and a measurement or estimate of turbine section component temperature, and (ii) a value of the second demand signal at a previous time step, and a measurement or estimate of tip clearance.

With reference to FIG. 1, a ducted fan gas turbine engine generally indicated at 10 has a principal and rotational axis X-X. The engine comprises, in axial flow series, an air intake 11, a propulsive fan 12, an intermediate pressure compressor 13, a high-pressure compressor 14, combustion equipment 15, a high-pressure turbine 16, and intermediate pressure turbine 17, a low-pressure turbine 18 and a core engine exhaust nozzle 19. A nacelle 21 generally surrounds the engine 10 and defines the intake 11, a bypass duct 22 and a bypass exhaust nozzle 23.
The gas turbine engine 10 works in a conventional manner so that air entering the intake 11 is accelerated by the fan 12 to produce two air flows: a first air flow A into the intermediate pressure compressor 13 and a second air flow B which passes through the bypass duct 22 to provide propulsive thrust. The intermediate pressure compressor 13 compresses the air flow A directed into it before delivering that air to the high pressure compressor 14 where further compression takes place.
The compressed air exhausted from the high-pressure compressor 14 is directed into the combustion equipment 15 where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby drive the high, intermediate and low-pressure turbines 16, 17, 18 before being exhausted through the nozzle 19 to provide additional propulsive thrust. The high, intermediate and low-pressure turbines respectively drive the high and intermediate pressure compressors 14, 13 and the fan 12 by suitable interconnecting shafts.
The high pressure turbine components of an aero gas turbine engine are located in the hottest part of the engine. At around 1600° C., the temperature of the gas stream is greater than the melting temperature of the nickel-based alloys from which the high pressure turbine nozzle guide vanes and rotor blades are typically cast.
It is usual, therefore, to cool nozzle guide vanes and rotor blades internally using cooling air taken from the exit of the high pressure compressor. The cooling air, which bypasses the combustor, may nonetheless be at a temperature of over 700° C. on exit from the compressor section. However, the cooling air, even if returned into the flow path of the turbine downstream of the combustor, does not return a full measure of work to the operation of the turbine. Thus, the greater the amount of cooling air that is extracted, the greater the associated loss in engine efficiency.
One method of reducing the cooling air requirement is to cool the cooling air before it enters the high pressure turbine components. This can be achieved by putting the cooling air in heat exchange relationship with a cooler fluid. For example, many aero gas turbine engines have a bypass air stream which can serve as the cooler fluid. In conventional arrangements, a portion of that air stream is diverted at an offtake into a duct in which the heat exchanger is located. The diverted portion of air, after having passed over the heat exchanger, is then returned to the main bypass air stream.
U.S. Pat. No. 4,254,618 proposes bleeding cooling air from the compressor discharge of a turbofan engine, and routing the cooling air to a heat exchanger located in a diffuser section of the fan duct. The cooled cooling air is then routed through compressor rear frame struts to an expander nozzle and thence to the turbine.
Efficient operation of rotors is also promoted by reducing the leakage of working fluid between the engine casing and the tips of the rotor blades. For example, engine-casing cooling systems allow the clearance between a turbine stage casing and the rotor blade tips of the stage to be adjusted so that tip clearance, and hence tip leakage, can be reduced.
In large civil aero engines, engine casing cooling air is typically taken from the fan stream or from an early compressor stage. It is then fed to a manifold which encircles the engine at or near the plane of the target turbine stage. On exit from the manifold, the air impinges on the outside of the turbine stage casing, causing it to contract and reduce the rotor blade tip clearance.
U.S. Pat. No. 5,048,288 proposes a turbine tip clearance control arrangement in which the outer air seal of a gas turbine engine is continuously cooled by compressor discharge air and by a by-pass line which can be throttled or shut off.
U.S. Pat. No. 6,487,491 proposes closed-loop tip clearance control, in which case the tip clearance of the engine is monitored during flight, including take off and landing, and adjusted by controlling air flow adjacent the engine casing in response to thermal growth.
US 2008/0112798 proposes a gas turbine engine having a heat exchanger used for cooling pressurized air bled from the compressor. A distribution network joins the heat exchanger to the turbine for selectively channelling air from the heat exchanger below the blades and above the shroud for controlling blade tip clearance.

Gas turbine engine having a multi-variable closed loop controller for regulating tip clearance


A smoke detector apparatus that provides a generally continuous supply of electrical power to a smoke detector unit. The apparatus provides flexibility in locating the detector unit while still generally maintaining uninterrupted access to electrical power. In various forms, the apparatus allows for mounting of a smoke detector unit remote from an electrical wall outlet. Generally uninterrupted power from the electrical system of a home or building to the smoke detector unit may be provided by way of an integral mounting plate, blocking member, and/or outlet covers.

The invention relates to smoke detector units and, more particularly, to apparatus securely connecting detector units to electrical systems in a home or building.
The risk and extent of property loss, personal injury, and death from fire and smoke can be minimized when smoke detectors are properly employed to provide warning during the initial stages of a fire. Laws in many jurisdictions require that smoke and/or heat detectors be provided in public and commercial buildings and private homes. This has led to the development of a wide variety of commercially available smoke detectors, some of which are battery operated and some of which are connected to the electrical system of a home or building by a permanent wiring connection or by reception of the male plugs on their power cords in female wall outlets.
A permanent wiring connection is preferable, but costly and difficult to install after construction of a home or building. A drawback of using a permanent wiring connection is the necessity that the smoke detector be connected at the location of the permanent wiring connection. This may result in the smoke detector being mounted in an inaccessible or non-ideal location. Smoke detectors that plug into a female wall outlet are susceptible to inadvertent removal from the female wall outlet. There may be excess length of power cord between the smoke detector and the female wall outlet. The excess length may be pulled, such as by a vacuum cleaner or a foot of person, thus pulling the male plugs from the female wall outlet and disconnecting the power supply to the smoke detector. The male plugs may also be removed from the female wall outlet for access to the female wall outlet by a user. This presents the risk that the user will inadvertently forget to reinsert the male plugs into the smoke detector, thus rendering the smoke detector inoperable.
Fire safety experts often recommend that smoke alarm detectors be placed on or near the ceiling of a room and preferably near the center. A problem with ceiling mounted detectors powered by batteries, rechargeable or otherwise, is that they are difficult to reach and deactivate in the event that the alarm is inadvertently triggered by a condition which is not dangerous. For example, ordinary cigarette and cooking smoke have the capability to trigger a smoke alarm, as does steam from a kitchen or a shower, and a triggered alarm will normally remain operative until the alarm triggering condition dissipates or someone deactivates the device. Furthermore, fire safety experts recommend that ceiling mounted detectors powered by rechargeable batteries be tested at least every six months to ensure that the batteries are still operational, and nonrechargeable batteries must be replaced fairly often.
Testing, recharging, and replacing batteries in a smoke alarm is often accomplished by pushing a button or other activating switch on the body of the detector. It can be difficult or impossible, however, particularly for elderly or infirmed persons, to reach ceiling mounted detectors or wall-mounted detectors at higher altitudes for these purposes.
Residential home owners who live in locations where construction codes do not require hard-wired smoke detectors or live in structures built prior to existing code requirements also may need smoke alarm detectors that are not powered exclusively by batteries. For example, a residential home owner may prefer the safety and convenience of having a hard-wired type smoke detector instead of having the inconsistent reliability of battery powered smoke detectors.
Prior smoke detectors have attempted to address the various problems facing battery powered smoke detectors. One such device is disclosed in U.S. Pat. No. 5,432,500, which discloses a smoke detector that is threaded into a light fixture, using the wiring thereto as its power source. While the disclosed detector does not depend upon batteries for operation, the detector may be inadvertently turned off by the light switch which controls the ceiling light fixture.
Despite the existing laws and building codes pertaining to smoke detectors, it is estimated that at least one-third of all battery powered smoke detectors are inoperable at a given point in time due to depleted or absent batteries. However, as many existing dwellings were not built to allow for hard-wired AC detectors and have no immediate means by which to utilize the more reliable AC models, they have been forced to rely on battery powered units.
In accordance with the present invention, an apparatus that provides uninterrupted power to a smoke detector unit from a home""s or building""s electrical system is provided. Unlike smoke detectors that are hard-wired to electrical systems, the present apparatus provides a home owner or building occupant significant flexibility in term of where to locate the detector unit while still securing uninterrupted access to the power provided by the electrical system of the home or building.
In a preferred form, the apparatus includes a power supply line of adjustable length with an integral outlet cover plate and male plug blades at one end. In this manner, one can remove the existing cover plate, insert the male plug blades into the wall outlet, and fasten the integral cover plate to the wall or ceiling to prevent accidental disconnections of the power supply line from the electrical system of the home or building. Another form of the apparatus allows a user to use the female socket of a standard lamp to provide uninterrupted power from the electrical system to the smoke detector unit via a blocking member of the smoke detector unit that covers the lamp switch in the on position, and an outlet cover that maintains the lamp cord plugged into the wall outlet. In yet another form of the apparatus, one can use the apparatus with the wiring of a light fixture. Either a protective sheath can be provided on the smoke detector unit for covering a switch, e.g., a pull chain, at the light fixture, or a wall switch faceplate can be used for covering a standard wall switch. In this form where the blocking member is the wall switch faceplate, the smoke detector unit can include a socket connected to internal power circuitry, and the wall switch faceplate can include a radio transmitter with a switch for sending a radio signal to receiving circuitry that provides power through the internal power circuitry to a female lightbulb socket formed in the smoke detector unit.
As is apparent, the present apparatus allows considerable latitude in determining the location of the smoke detector unit rather than having the location preset as dictated by a permanent wiring connection, placed by a home builder or the like, while still securing access to uninterrupted power from the electrical system of a home or building unlike prior plug in types using only power cords. In various forms, the apparatus allows the user to change the length of the power supply line to allow the unit to be mounted at various locations without excess length of the power supply line exposed for accidental contact by a vacuum cleaner or a person""s foot. The locations can be remote from the wall outlet, or next to any lamp in the home or building, or using the wiring for any light fixture in the home or building. In each of the above-described forms, substantially uninterrupted power from the electrical system of the home or business to the smoke detector unit is maintained by way of an integral mounting plate or a blocking member and/or outlet covers.
In a preferred form of the invention the smoke detector apparatus includes a small, portable smoke detector unit that is capable of installation in the home or building. The smoke detector unit has a smoke detecting mechanism therein. The smoke detecting mechanism may comprise ionization type detection and/or photoelectric detection. An audible alarm is provided for sounding when the smoke detection mechanism detects dangerous amounts of smoke in the home or building. The smoke detector unit contains electrical circuitry for receiving power to operate the smoke detecting mechanism and the audible alarm.
A power supply line is provided to connect the smoke detecting unit to the electrical system of the home or building. A first end of the power supply line has a mounting plate intergrally formed as by molding thereon. The mounting plate is in the form of an outlet cover plate including openings for allowing male plug blades to be inserted into the standard female electric socket of the wall outlet of the electrical system of the home or building. The first end may also have a standard female electrical socket formed thereon. A second end of the power supply line is electrically connected to the smoke detector unit to provide power to the electrical circuitry of the smoke detector unit. The power supply line may be cut to tailor its length so that it extends between the mounting plate and the smoke detector unit wherever the smoke detector unit is mounted in the home or building. The mounting plate replaces the existing cover plate of the wall outlet and is fastened to the wall so that male plug blades carried thereby and electrically connected to the power supply line are secured in the female electric socket.
The smoke detector unit may have a xe2x80x9cquick connectxe2x80x9d feature for electrically connecting the power supply line with the electrical circuitry of the smoke detector unit. The xe2x80x9cquick connectxe2x80x9d feature may include push down tabs that make electrical contact with the power supply line.
A conduit is also provided for attaching a portion of the power supply line between the ends of the power supply line to a wall or other surface of the home or building. The conduit can be cut to the necessary length to cover the portion of the power supply line. The conduit may be attached to the wall using an adhesive backing on the conduit. The conduit may be formed of extruded plastic and may be generally U-shaped in cross section for receiving the portion of the power supply line therein.
The mounting plate is adapted for fitting over a standard wall outlet electrically connected to the electrical system in a home or building. The mounting plate may be formed in a decorative shape, such as a fire truck or a cartoon character for use in a child""s bedroom. The wall outlet may have one or more electric sockets. An existing outlet cover in a home or building may be removed and replaced with the mounting plate. The interior of the mounting plate has male plug blades electrically connected to the first end of the power supply line for insertion into the electric socket of the wall outlet to supply power from the electrical system to the electrical circuitry of the smoke detector unit. Fastening the mounting plate to the wall outlet provides a secure connection between the electrical system of the home or building and the smoke detector unit. When the mounting plate is fastened to the wall outlet the power supply line resists accidental removal from the electric socket. For example, accidentally pulling the power supply line, such as by engaging it with a vacuum cleaner during ordinary cleaning or inadvertently tripping over it with a person""s foot, will not interrupt the power supply to the smoke detector unit.
The mounting plate may have an opening for access to an electric socket of the wall outlet not occupied by the plug blades. This allows users to use available electric sockets on the wall outlet for other uses while still maintaining the power supply line in connection with the electrical power system of the home or business. The mounting plate can also include a retractable cover to block access an open electric sockets on the wall outlet. This is particularly useful in homes or buildings where small children may be present to prevent electrocution. The retractable cover may have slots for insertion of the male end of an electric cord. The retractable cover may have an integral spring system to force the slots out of alignment with corresponding slots of the electric socket. A user could insert the male end of an electric cord into the slots of the retractable cover and rotate the retractable cover back into alignment with the corresponding slots of the electric socket.
In one form, the smoke detector unit has a non-standard female power outlet formed thereon. The non-standard female power outlet provides electrical power between the electrical circuitry of the smoke detector unit and an accessory. The accessory is designed with a non-standard male plug for insertion into the non-standard female power outlet of the smoke detector unit.
The accessory may have a light for indicating that power is being supplied to the accessory and thus the smoke detector unit.
The accessory may comprise a battery for providing back-up power supply to the electrical circuitry of the smoke detector unit. In the event that the electrical system of the home or building does not supply power to the wall outlet the battery will supply power to electrical circuitry of the smoke detector unit. The accessory may have a battery charger for maintaining the battery at full strength with power from the electrical system of the home or building. The accessory may also have a clock for displaying the time. The clock also provides a visible indication that the smoke detector unit is receiving power from either the battery or the electrical system of the home or building. A light may also be provided on the accessory for indicating when the battery is supplying power to the smoke detector unit and the electrical system of the home or building is not operational.
Other accessories may also be provided for attachment to the smoke detector unit. For example, the accessory may comprise a carbon monoxide detector for alerting when dangerous levels of carbon monoxide gas are present in the home or building. The accessory may alternatively comprise a nightlight for providing illumination. Multiple accessories may be attached to each other using non-standard female power outlets similar to that of the smoke detector unit formed on each accessory. The accessory comprising the nightlight does not have such a power outlet so that it may be used on the end of another accessory or the smoke detector unit without the danger that a small child may be electrocuted by contact with the power outlet.
In another form of the invention, an apparatus is provided including a small, portable smoke detector unit with electrical circuitry therein electrically connected to an intermediate conductive member for supplying power from the electrical system. The intermediate conductive member may include a standard lightbulb socket, such as on a lamp or a ceiling fixture. The intermediate conductive member may also include electrical power leads. The smoke detector unit may have a xe2x80x9cquick connectxe2x80x9d feature formed for receiving the power leads. The xe2x80x9cquick connectxe2x80x9d feature may comprise push down tabs that make electrical contact with the power leads.
Power from the electrical system of the home or building to the intermediate conductive member may be controlled by a switch operable by a user between on and off states thereof. In one form the smoke detector unit has male socket threads formed thereon for insertion into the standard lightbulb socket to provide an electrical connection between the standard lightbulb socket and the male socket threads when the switch is in the on state. The smoke detector has a blocking member integral therewith for preventing access to the switch and preventing the accidental operation of the switch by a user from the on to the off state.
A standard female lightbulb socket may be formed in the smoke detector unit for receiving the lightbulb. The socket is electrically connected to the internal power circuitry of the smoke detector unit. The electrical circuitry constantly supplies power to the smoke detecting mechanism and the audible alarm mechanism of the smoke detector unit. The internal power circuitry electrically connects the electrical circuitry and the female lightbulb socket. The internal power circuitry may be switched on and off so that power may be supplied to the female lightbulb socket such that the lightbulb in the female lightbulb socket may be turned on or off without turning off the power from the electrical system of the home to the electrical circuitry of the smoke detector unit. The smoke detector unit may have a hoop integral therewith, the hoop being adapted for attachment of a lampshade to cover the lightbulb inserted in the female lightbulb socket formed in the smoke detector unit.
For a switch mounted to a lightbulb socket on a standard ceiling fixture or on a lamp, the blocking member of the smoke detector may comprise a protective sheath that surrounds the switch to cover the switch in the on state and to prevent access thereto. For a switch mounting to a wall, such as a standard ceiling light switch, the blocking member may comprise a switch plate cover. The switch plate cover may have a recess therein to cover the switch in the on state and to prevent access thereto.
A fixture switch operatively associated with a radio signal transmitter may be provided. For example, the switch plate cover may have the fixture switch formed thereon. The fixture switch may comprise a push button or a replica of a standard toggle found on most wall switches. The transmitter may signal a receiver in the smoke detector unit upon operation of the fixture switch to operate the internal power circuitry of the smoke detector unit to provide power from the electrical circuitry of the smoke detector unit to the socket of the smoke detector unit. Such a fixture switch allows for the activation of a lightbulb in the smoke detector unit without adding any additional electrical wiring to the electrical system of a home of building while maintaining uniterrupted power from the electrical system to the smoke detector unit.


An integrated circuit has a circuit for adjusting the time period of an output signal. The adjustment can compensate for semiconductor processing variations varying from wafer to wafer. The circuit adjusts the delay generated by an adjustable delay line, and adjusts the occurrence in time of the trailing edge of the output signal. A value which corresponds with a suitable delay to be generated by the adjustable delay line is stored in nonvolatile storage on the integrated circuit.

1. Field of the Invention
The present invention relates to clocked integrated circuits generally, and more particularly to integrated circuits with adjustable delay lines to support timing requirements.
2. Background
A variety of integrated circuits with different mission functions have high clock rates and as a result have precise timing requirements. For example, in some memory devices, the time between applying a read signal in one clock cycle, and sampling in another clock cycle, the data output in response to the read signal must be precisely controlled. However, producing signals with precise delays across a product line is a nontrivial problem due to semiconductor process variations that occur from one wafer to another wafer, from one integrated circuit to another integrated circuit on the same wafer, and even across different portions of the same integrated circuit.
A common approach to addressing process variations is to employ a design methodology with a "worst case" modeling approach. Such an approach consistently underestimates circuit performance, and results in expensive over-design. A needed approach is to make integrated circuits that satisfy demanding timing requirements without unnecessary and expensive over-design.


An implantable cardiac stimulation device monitors the progression and/or regression of heart disease. The device comprises a sensing circuit that senses activity of a heart and provides an electrogram for each one of a plurality of cardiac cycles, an averaging circuit that averages a number of the plurality of electrograms at spaced apart intervals to provide averaged trend electrograms, and a data generator that provides a metric reflective of progression or regression of heart failure responsive to a difference between a current averaged trend electrogram and a previous averaged trend electrogram.

Implantable cardiac devices are well known in the art. They may take the form of implantable defibrillators or cardioverters which treat accelerated rhythms of the heart such as fibrillation or implantable pacemakers which maintain the heart rate above a prescribed limit, such as, for example, to treat a bradycardia. Implantable cardiac devices are also known which incorporate both a pacemaker and a defibrillator.
A pacemaker may be considered to be comprised of two major components. One component is a pulse generator which generates the pacing stimulation pulses and includes the electronic circuitry and the power cell or battery. The other component is the lead, or leads, having electrodes which electrically couple the pacemaker to the heart. A lead may provide both unipolar and bipolar pacing and/or sensing electrode configurations. In the unipolar configuration, the pacing stimulation pulses are applied or intrinsic responses are sensed between a single electrode carried by the lead, in electrical contact with the desired heart chamber, and the pulse generator case. The electrode serves as the cathode (negative pole) and the case serves as the anode (positive pole). In the bipolar configuration, the pacing stimulation pulses are applied or intrinsic responses are sensed between a pair of closely spaced electrodes carried by the lead, in electrical contact with the desired heart chamber, with the most proximal electrode serving as the anode and the most distal electrode serving as the cathode.
Pacemakers deliver pacing pulses to the heart to induce a depolarization and a mechanical contraction of that chamber when the patient's own intrinsic rhythm fails. To this end, pacemakers include sensing circuits that sense cardiac activity for the detection of intrinsic cardiac events such as intrinsic atrial events (P waves) and intrinsic ventricular events (R waves). By monitoring such P waves and/or R waves, the pacemaker circuits are able to determine the intrinsic rhythm of the heart and provide stimulation pacing pulses that force atrial and/or ventricular depolarizations at appropriate times in the cardiac cycle when required to help stabilize the electrical rhythm of the heart.
Pacemakers are described as single-chamber or dual-chamber systems. A single-chamber system stimulates and senses in one chamber of the heart (atrium or ventricle). A dual-chamber system stimulates and/or senses in both chambers of the heart (atrium and ventricle). Dual-chamber systems may typically be programmed to operate in either a dual-chamber mode or a single-chamber mode.
Recently, there has been the introduction of pacing systems that stimulate in corresponding chambers of the heart as, for example, the right ventricle (RV) and left ventricle (LV). These are termed biventricular stimulation devices.
Biventricular pacing has been shown to coordinate contractions of the left and right ventricles, reduce the amount of blood flow that leaks through the mitral valve, and decreases the motion of the septal wall that separates the chambers of the heart. Such motion can affect the quantity of blood that the ventricle can pump out in a single beat.
Biventricular pacing has been found to be particularly advantageous in patient's suffering from congestive heart failure (CHF) because of the improved ability of the left ventricle to fully pump blood from the heart. As a result, patients are able to tolerate greater exertion, have a longer life span, and experience a higher quality of life.
Congestive heart failure (CHF) is a debilitating, end-stage disease in which abnormal function of the heart leads to inadequate blood flow to fulfill the needs of the body's tissues. Typically, the heart loses propulsive power because the cardiac muscle loses capacity to stretch and contract. Often, the ventricles do not adequately fill with blood between heartbeats and the valves regulating blood flow may become leaky, allowing regurgitation or backflow of blood. The impairment of arterial circulation deprives vital organs of oxygen and nutrients. Fatigue, weakness, and inability to carry out daily tasks may result.
Not all CHF patients suffer debilitating symptoms immediately. Some may live actively for years. Yet, with few exceptions, the disease is relentlessly progressive.
As CHF progresses, it tends to become increasingly difficult to manage. Even the compensatory responses it triggers in the body may themselves eventually complicate the clinical prognosis. For example, when the heart attempts to compensate for reduced cardiac output, it adds muscle causing the ventricles to grow in volume in an attempt to pump more blood with each heartbeat. This places a still higher demand on the heart's oxygen supply. If the oxygen supply falls short of the growing demand, as it often does, further injury to the heart may result. The additional muscle mass may also stiffen the heart walls to hamper rather than assist in providing cardiac output.
Current standard treatment for heart failure is typically centered around medical treatment using ACE inhibitors, diuretics, and digitalis. It has also been demonstrated that aerobic exercise may improve exercise tolerance, improve quality of life, and decrease symptoms. Only an option in 1 out of 200 cases, heart transplantation is also available. Other cardiac surgery is also indicated for only a small percentage of patients with particular etiologies. Although advances in pharmacological therapy have significantly improved the survival rate and quality of life of patients, patients who are refractory to drug therapy, have a poor prognosis and limited exercise tolerance.
Cardiac pacing is now considered a primary treatment for patients with drug-refractory CHF. By tracking the progression or regression of the heart disease more closely, stimulation therapy could be managed more effectively. Hence, it would be advantageous if the implanted cardiac stimulation device were able to aid in the tracking of the progression or regression of the heart disease.
One method of tracking a patient's CHF condition relies upon electrogram (EGM) morphology. Unfortunately, this has required the implanted device to locally store one averaged EGM periodically and then turn computations based on the averaged EGM's over to an external programmer. This not only requires excessive memory space within the device, but also time and device battery energy loss to support the data transfer from the device to the programmer. Hence, it would be desirable if the implantable device could monitor the progression and/or regression of heart disease without requiring excessive memory space or consuming excessive time and battery power. The present invention addresses these and other issues.

Implantable cardiac stimulation device that monitors progression and regression of heart disease responsive to differences in averaged electrograms and method


A process is described for preparing a compound of the formula or the S-enantiomer thereof,. wherein:. R is alkyl, aryl, cycloalkyl, aralkyl, or cycloalkylalkyl, PA1 R.sup.1 is halogen; PA1 R.sup.2 is halogen, alkyl, cycloalkyl, aryl or ##STR1## wherein the process comprises treating the associated racemic alcohol with an acylating. agent ##STR2## (wherein L is a leaving group) and an enzyme or microorganism capable of enantioselective acylation. This process may also be used to isolate the unreacted R- or S-alcohol. The acylated product may be enantioselectively hydrolyzed with a lipase or lipase-supplying microorganism to the S- or R-alcohol. Compounds prepared by this invention are useful antipsychotic agents or useful intermediates therefor.

Antipsychotic agents are described in U.S. Pat. Nos. 4,605,655 and 4,994,460, issued Aug. 12, 1986 and Feb. 19, 1991, respectively. Of these agents, a compound identified as BMY 14,802 having the structure ##STR3## is preferred. The R(+) isomer of BMY 14,802 and the other compounds disclosed in these patents are more active. No enzymatic or microbial preparations of these compounds is known, and chemical selective preparation is difficult. A need exists, therefore, for an enantioselective preparation of these compounds in high yield and high stereoisomeric purity.

Enantioselective preparation of halophenyl alcohols and acylates


A composite scanning tunneling microscope comprises a first objective optical system for collimating an optical flux from a sample, a second objective optical system for condensing the optical flux thus collimated, and a transparent member disposed between the first and the second objective optical systems. A through hole is perforated along an optical axis in the center of the first objective optical system. A tube scanner member has a probe for detecting a tunnel current disposed at one end thereof. The tube scanner member passes through the hole of the first objective optical system without a contact therewith. The other end of the tube scanner member is fixed to the transparent member. The tube scanner member fixed to the transparent member is separate from and independent of an optical microscope, so that a tunnel current may stably be detected without influences on the probe from vibrations of the optical microscope.

1. Field of the Invention
The present invention relates to a scanning tunneling microscope. More particularly, the present invention relates to a composite scanning tunneling microscope, in which a tunneling microscope is combined with an optical microscope.
2. Related Background Art
A conventional example of composite tunneling microscope is disclosed in Japanese Patent Application Laid-open No. 2-16403. This example is briefly explained in the following.
As shown in FIG. 6, a tunneling microscope as disclosed in the above Laid-open Patent has a probe 2 for tunnel current detection unitedly fixed on an objective lens 1, which detects a very weak electric current from the probe 2 through a conductive layer 3.
Further, the above Laid-open Patent describes another tunneling microscope as shown in FIG. 7, in which a glass plate 5, which does not affect an optical image, is disposed between an objective lens 1 and a sample 4 and in which a probe 6 is attached to the glass plate 5. In this example, the glass plate 5 is fixed to a lens barrel supporting the objective lens 1 or to a housing of the microscope.
Since the probe is unitedly incorporated into the optical microscope in the above conventional composite tunneling microscopes, vibrations of the optical microscope are readily transmitted to the probe of the tunneling microscope, which results in inability to obtain a high resolving power of atomic level based on detection of tunnel current.
The incorporation of the probe with the objective lens is not easy in position adjustment to set the probe at a position where the tip of probe is located in a depth of focus of the optical microscope, which leads to difficulties in exchange of probe.


A printed circuit board includes a first semiconductor package on a first surface layer of a printed wiring board and a second semiconductor package on a second surface layer where a bus signal is transmitted from the first to the second semiconductor package. A first bus wiring path from a signal terminal on an inner circumference side of the first semiconductor package via a via hole and the second surface layer to a signal terminal on an outer circumference side of the second semiconductor package and a second bus wiring path from a signal terminal on an outer circumference side of the first semiconductor package via the second surface layer and a via hole to a signal terminal on an inner circumference side of the second semiconductor package are provided, thus securing a return current path for a signal current and realizing a high density wiring while suppressing radiation noise.

1. Field of the Invention
The present invention relates to a bus wiring formed on a printed circuit board.
2. Description of the Related Art
A higher speed in operations and a higher density of wirings are demanded for a printed circuit board along with sophistication of electronics devices in recent years. For that reason, a bus wiring is frequently used in which plural signal lines through which a signal can be transmitted at a high speed are arranged in parallel. In a case where the signals are transmitted by using the bus wiring from a transmission-side semiconductor package to a reception-side semiconductor package, lengths of respective wirings are set to be equal to each other. If a large difference exists in the lengths of the respective wirings, an operational timing of the reception-side semiconductor package is deviated, and noise is increased because of a difference in the timing at which the signals are reflected at connection points of the respective wirings.
In a case where the transmission-side semiconductor package is mounted on one of surfaces of a multi-layered printed wiring board and the reception-side semiconductor package is mounted on the other surface, the bus wiring is arranged by using via holes. A ground layer or a power supply layer is generally formed on an inter layer of the multi-layered printed wiring board, and the ground layer or the power supply layer serves as a return path for the signal flowing through the signal wiring such as the bus wiring.
The via holes are prepared also in the ground layer or the power supply layer in the case of the above-described multi-layered printed wiring board. To design the printed wiring board at a high density in recent years, the bus wirings are arranged to be adjacent to each other as much as possible. For that reasons, the via holes are also arranged to be adjacent to each other. However, if the via holes prepared in the ground layer or the power supply layer are continuously arranged, the return path for the signal is divided by the via holes. Thus, radiation noise is increased.
Japanese Patent Laid-Open No. 8-340161 discloses a configuration in which the via holes are prepared in a diagonal manner, or a wider interval is designed every two or four via holes in a case where the bus wirings are formed on the multi-layered printed wiring board. The return path is secured by preparing the via holes in the above-described manner.
In recent years, a semiconductor package of a ball grid array (BGA) type is used instead of a semiconductor package of the QFP type disclosed in Japanese Patent Laid-Open No. 8-340161. Accordingly, the following configuration with regard to electrode terminals connected to the bus wirings is more frequently used. That is, the bus wirings are connected to not only the electrode terminals arranged on an outermost circumference of the semiconductor package but also the electrode terminals arranged on an inner circumference of the semiconductor package. It is therefore difficult to arrange the bus wirings at equal distances.
When the number of bus wirings is increased in the case of the multi-layered printed wiring board, the number of the via holes prepared in the ground layer or the power supply layer of the signal wirings is increased, and it is difficult to secure the return path for the signal. As described in Japanese Patent Laid-Open No. 8-340161, even when the via holes are prepared in a diagonal manner, the area for preparing the via holes is enlarged, and a degree of freedom for the board design is largely impaired. That is, if the via holes are prepared in a diagonal manner, the area for mounting electronic components such as bypass capacitors is limited, and the area for forming the other signal wirings is also limited.


A liquid crystal display device provided with an insulating substrate, a thin film transistor formed on the insulating substrate, and a pixel electrode and a storage capacitor electrically connected to the thin film transistor, includes a first conductive layer formed on the insulating substrate; a first insulating layer formed on the first conductive layer and having an opening for exposing a part of the first conductive layer; a second conductive layer formed on the first conductive layer at least within the opening; a second insulating layer for covering the second conductive layer; and a third conductive layer for covering the second insulating layer at least within the opening, and the storage capacitor is formed from a stacked layer structure including the second conductive layer, the second insulating layer and the third conductive layer.

The present invention relates to a liquid crystal display device and a fabrication method for the liquid crystal display device, and more particularly, it relates to an active matrix type liquid crystal display device including thin film transistors and a fabrication method for the same.
Recently, an active matrix type liquid crystal display device is widely used as a display device for a personal computer, a thin television set, a display for a video imaging device or a digital camera, or the like. An equivalent circuit of one pixel of an active matrix type liquid crystal display device including a thin film transistor as an active element (hereinafter referred to as the xe2x80x9cTFT type liquid crystal display devicexe2x80x9d) is shown in FIG. 6. An area where pixels (pixel regions) are arranged in the form of a matrix corresponds to a display region.
In the TFT type liquid crystal display device, each pixel includes a thin film transistor (hereinafter referred to as the xe2x80x9cTFTxe2x80x9d), and a liquid crystal capacitor CLC and a storage capacitor CS connected to the drain D of the TFT. The liquid crystal capacitor CLC and the storage capacitor CS are together designated as a pixel capacitor Cpix. To the gate G of the TFT, a gate line (scanning line) is connected, and to the source S thereof, a source line (signal line) is connected. During a period when a scan signal is applied to the gate G (i.e., during one scan period), a signal voltage applied from the source line to the source S of the TFT is applied to a drain side electrode of the liquid crystal capacitor CLC (hereinafter referred to as the xe2x80x9cpixel electrodexe2x80x9d) and a drain side electrode of the storage capacitor CS (hereinafter referred to as the xe2x80x9cstorage capacitor electrodexe2x80x9d). On the other hand, to another electrode of the liquid crystal capacitor CLC (hereinafter referred to as the xe2x80x9ccounter electrodexe2x80x9d) and another electrode of the storage capacitor CS (hereinafter referred to as the xe2x80x9cstorage capacitor counter electrodexe2x80x9d), a predetermined counter voltage (common voltage) is applied through a counter electrode or storage capacitor counter electrode line (common line) COM. The storage capacitor counter electrode line COM formed on a TFT substrate is electrically connected to a counter electrode formed on a counter substrate. A net voltage applied to the liquid crystal capacitor CLC corresponds to a difference between the signal voltage and the counter voltage. The alignment of liquid crystal is changed in accordance with this voltage, so as to obtain a display state corresponding to the signal voltage.
In a period when a scan signal is not applied to the gate G (namely, when a TFT connected to another gate line is selected), the liquid crystal capacitor CLC and the storage capacitor CS are electrically insulated from the source line by the TFT. Until the TFT of interest is selected next, the liquid crystal capacitor CLC and the storage capacitor CS keep the predetermined display state by keeping the previously applied voltage. When the voltage holding property of the TFT and the pixel capacitor Cpix is low during this period, the display quality is degraded.
In order to attain a desired voltage holding property, a storage capacitor CS having a comparatively large capacitance value is sometimes required. When the areas of the storage capacitor electrode and the storage capacitor counter electrode are increased in order to increase the capacity of the storage capacitor CS, the aperture ratio can be degraded in a transmission type liquid crystal display device because these electrodes are generally formed from opaque materials.
Japanese Laid-Open Patent Publication No. 5-61071 discloses a TFT type liquid crystal display device using a storage capacitor having large capacity in a pixel. FIGS. 7A through 7C are cross-sectional views for showing procedures for forming a TFT and the storage capacitor of the liquid crystal display device described in this publication.
According to the publication, a groove (trench) 122 is formed in the surface of an insulating substrate 121 on which a TFT is to be formed, and the storage capacitor (capacity component) is formed in this groove 122. Furthermore, the storage capacitor is formed from a first electrode 123 formed integrally with a semiconductor layer of the TFT in the same procedure, a second electrode 126a formed from the same material as a gate electrode of the TFT and insulating films 124a and 125a formed from the same material as a gate insulating layer of the TFT. Thus, the structure and the fabrication process are simplified.
The TFT substrate including the TFT and the storage capacitor part shown in FIGS. 7A through 7C are fabricated as follows:
(1) A groove 122 is formed in the surface of a quartz substrate 121 through wet etching using a mixture of HF and NH4F (1:6) as an etchant.
(2) A first polysilicon layer 123 with a thickness of 80 nm is formed by the low pressure CVD. Silicon is implanted into the first polysilicon layer 123 twice at energy of 30 keV and dose of 1xc3x971015/cm2 and at energy of 50 keV and dose of 1xc3x971015/cm2, respectively. The resultant is subjected to solid phase annealing, and part of the first polysilicon layer 123 is removed by etching.
(3) The first polysilicon layer 123 is thermally oxidized at 1000xc2x0 C., thereby forming a SiO2 film 124 with a thickness of 50 nm in the surface thereof. A part of the first polysilicon layer 123 not oxidized is ultimately formed into a first electrode of the storage capacitor and the semiconductor layer (the source, the channel and the drain) of the TFT.
(4) With an area of the SiO2 film 124 where the TFT is to be formed protected by a resist layer, arsenic ions (As+) are implanted at energy of 30 kev and dose of 5xc3x971015/cm2 into the part of the first polysilicon layer 123 to be formed into the first electrode of the storage capacitor.
(5) After removing the resist layer, a SiN film 125 with a thickness of 30 nm is formed by the low pressure CVD so as to cover the SiO2 film 124.
(6) A second polysilicon layer 126 with a thickness of 350 nm is formed on the entire surface of the substrate by the low pressure CVD, and the resistance is reduced by PSG.
(7) The second polysilicon layer 126 and the SiN film 125 are patterned by using a gas including CF4 and O2 (95:5), thereby forming a gate electrode 126b of the TFT, a second electrode 126a of the storage capacitor, a SiN gate insulating layer 125b and a storage capacitor SiN film 125a. Then, arsenic ions are implanted through the SiO2 film 124 into the first polysilicon layer 123 included in the TFT at energy of 160 keV and dose of 1xc3x971015/cm2, thereby forming an LDD (lightly doped drain).
(8) A resist is formed so as to cover the second electrode 126b, and arsenic ions are implanted at energy of 140 keV and dose of 2xc3x971015/cm2, thereby forming an n-channel. After removing the resist, another resist is formed on the entire surface, and boron ions (B+) are implanted at energy of 30 keV and dose of 2xc3x971015/cm2, thereby forming a p-channel.
(9) After removing the resist, an interlayer insulating film 131 of phosphorus silica glass (PSG) is formed by the low pressure CVD.
(10) A first contact hole 132 is formed in the interlayer insulating film 131 and the SiO2 film 124 by the wet etching using the mixture of HF and NH4F.
(11) An ITO (indium tin oxide) film 129 with a thickness of 140 nm is formed by sputtering at 400xc2x0 C. The ITO film 129 is wet etched by using an etchant including HCl, H2O and HNO3 (300:300:50), thereby patterning the ITO film 129. Then, by using a resist as a mask, a second contact hole 134 is formed in the ITO film 129 by the wet etching using the mixture of HF and NH4F.
(12) An AlSi layer with a thickness of 600 nm is deposited by sputtering on the entire surface, and the AlSi layer is patterned into an electrode 130 by the wet etching using a mixture of H3PO4 and H2O (2:10). Then, a passivation film 133 of SiN with a thickness of400 nm is formed by the atmospheric pressure CVD. The passivation film 133 is patterned by the plasma etching using a gas including CF4 and O2 (95:5).
The capacitance value of the storage capacitor of the liquid crystal display device disclosed in the above-described publication depends upon the dimension of the opening of the groove, the depth of the groove, the kind (dielectric constant) of material used for forming a dielectric layer and the thickness of the dielectric layer. The most significant factor in forming the storage capacitor having a desired capacitance value in this conventional technique is control of the depth of the groove. Since the groove is formed by etching the surface of the substrate made from a single material, the depth of the groove is controlled by adjusting the etch time. Even when the etch time is accurately adjusted, however, the depth of the groove may be varied if the etching rate is varied. Variation in the capacitance value of the storage capacitor degrades the display quality of the liquid crystal display device.
When the capacitance value is small, the storage capacitor can store small charge. Therefore, the storage capacitor is largely affected by a leakage current flowing through the TFT and hence cannot keep the predetermined voltage. On the contrary, when the capacitance value of the storage capacitor is large, the storage capacitor cannot be sufficiently charged, and hence, the predetermined voltage cannot be applied to the ends of the storage capacitor and the liquid crystal capacitor.
The present invention was devised to overcome the aforementioned conventional problems, and a main object is providing a liquid crystal display device and a fabrication method for the same in which the capacitance value of a storage capacitor is minimally varied so as to attain high display quality.
The liquid crystal display device of this invention including an insulating substrate, a thin film transistor formed on the insulating substrate, and a pixel electrode and a storage capacitor electrically connected to the thin film transistor, includes a first conductive layer formed on the insulating substrate; a first insulating layer formed on the first conductive layer and having an opening for exposing a part of the first conductive layer; a second conductive layer formed on the first conductive layer at least within the opening; a second insulating layer for covering the second conductive layer; and a third conductive layer for covering the second insulating layer at least within the opening, wherein the storage capacitor is formed from a stacked layer structure including the second conductive layer, the second insulating layer and the third conductive layer. Thus, the aforementioned object is achieved.
In the liquid crystal display device, the second conductive layer can be in contact with the first conductive layer within the opening.
The liquid crystal display device may further include a third insulating layer formed between the first conductive layer and the second conductive layer, and the first conductive layer and the second conductive layer can be electrically insulated from each other.
In the liquid crystal display device, the first conductive layer and the third conductive layer may be electrically connected to each other, and the storage capacitor can be formed from a stacked layer structure including the first conductive layer, the third insulating layer and the second conductive layer, and another stacked layer structure including the second conductive layer, the second insulating layer and the third conductive layer.
In the liquid crystal display device, the first conductive layer and the third conductive layer are preferably mutually connected within a contact hole formed in the first insulating layer in a position outside of a display region.
The liquid crystal display device may further include a shielding layer formed over at least a channel of the thin film transistor, and the shielding layer and the first conductive layer may be formed from the same film and electrically insulated from each other.
In the liquid crystal display device, a gate insulating layer of the thin film transistor is preferably formed from a film the same as a film used for forming the second insulating layer.
In the liquid crystal display device, a channel, a source and a drain of the thin film transistor are preferably formed in a film the same as a film used for forming the second conductive layer.
In the liquid crystal display device, a gate electrode of the thin film transistor is preferably formed from a film the same as a film used for forming the third conductive layer.
The method of this invention of fabricating a liquid crystal display device including an insulating substrate, a thin film transistor formed on the insulating substrate, and a pixel electrode and a storage capacitor electrically connected to the thin film transistor, includes the steps of forming a first conductive layer on the insulating substrate; forming a first insulating layer on the first conductive layer; forming an opening for exposing a part of the first conductive layer in the first insulating layer by etching the first insulating layer with the first conductive layer used as an etch-stop layer; forming a second conductive layer on the first conductive layer at least within the opening; forming a second insulating layer for covering the second conductive layer; and forming a third conductive layer for covering the second insulating layer at least with in the opening, wherein the storage capacitor is formed from a stacked layer structure including the second conductive layer, the second insulating layer and the third conductive layer. Thus, the aforementioned object is achieved.
The method of fabricating a liquid crystal display device may further include the steps of forming, between the first conductive layer and the second conductive layer, a third insulating layer for electrically insulating the first conductive layer and the second conductive layer from each other; and electrically connecting the first conductive layer and the third conductive layer to each other, and the storage capacitor can be formed from a stacked layer structure including the first conductive layer, the third insulating layer and the second conductive layer, and a stacked layer structure including the second conductive layer, the second insulating layer and the third conductive layer.
Thus, the present invention can realize a storage capacitor having a large capacitance value with occupying a small area in which variation in the capacitance value is greatly reduced. As a result, the invention provides a liquid crystal display device having a high aperture ratio (namely, high brightness) and high picture quality.
Also, since the liquid crystal display device of this invention has a simple structure, the fabrication procedures can be simplified, so that a liquid crystal display device having high picture quality can be fabricated at low cost and high yield. The liquid crystal display device of this invention is suitably applied to a comparatively compact and highly refined liquid crystal display device using polysilicon as a semiconductor layer of a TFT.

Liquid crystal display device with capacitor in contact hole, and fabrication method for the same


A multiple array memory device formed on a single IC chip performing transfers of a series of data between the device and its interface at high speed. The device includes a memory having a plurality of groups of memory arrays. In a read operation, the device internally reads data from sequential locations starting at any desired address and extending across the memory arrays into a latch. As the data are output to the interface from the latch, sequential data from an adjacent group of array in the memory are internally read into the latch. Thus, a series of data can be output to the interface at high speed. The write operation is performed in a similar manner.

The invention relates generally to memory devices, more particularly, to a multiple array memory device for high speed data access.
Many attempts have been made to maximize the speed of memory devices beyond the basic memory technology. Conventionally, high speed access is achieved by operating on an internal memory word within the device that is several times, typically two or four times, the external word width at the interface of the device. Therefore, when a memory read is requested, the device reads not only the requested data but also additional data that are not yet requested and holds those additional data in a buffer making them available for reduced time access if they are subsequently requested. The same technique is implemented for a write cycle in that when a memory write is requested, the device holds the write data in a buffer until several other data words have been written into the buffer. The device then updates the memory cells with the write data.
There are several disadvantages to the conventional device. First, the high speed access is limited to the internal word width. That is, if the internal word width is four times the external word width, the high speed access mode is valid for a maximum of four external words. Secondly, this type of device naturally creates address boundaries. That is, the high speed access mode is valid only for four external words that align with the larger internal words. Moreover, to efficiently use the high speed access mode, the starting and ending addresses of external words must be aligned with the address of the internal word. Such alignment requires additional internal circuitry to count addresses and/or roll the addresses over to the least significant address in the internal word when the most significant address in the internal word is reached.
Early memory systems used cabinet technology in which several cabinets each containing a section of memory are connected. In operation, data could be input into or output from one cabinet while other cabinets were being accessed. Thus, access time could be reduced. However, this arrangement was too bulky and impractical. Additionally, such an arrangement was a distinct memory system composed of many devices of singular architecture forming a different overall architecture and not a single memory architecture nor a single chip architecture.
A high speed memory device of single architecture that allows faster access of data than the process technology inherently permits without the disadvantages described above is thus needed.

Multiple array memory device with staggered read/write for high speed data access


In each of two video appliances mutually connected by means of a transmission line, video, voice and other signals are converted to digital signals, subjected to time-division multiplexing and time-base compressing operations to generate a transmission signal having a repetition of signal presence and absence periods, and then the transmission signal is transmitted to the transmission line. While the transmission signal of the signal absence period is transmitted from one of the video appliances to the transmission line, the transmission signal of the signal presence period is transmitted from the other video appliance to the transmission line; whereas, while the transmission signal of the signal presence period is transmitted from one video appliance to the transmission line, the transmission signal of the signal absence period is transmitted from the other video appliance to the transmission line. In each of the video appliances, there is stopped at least one of the operation of a reception circuit of the video appliance during transmission of the transmission signal of the signal presence period from a transmission circuit to the transmission line and the operation of the transmission circuit of the video appliance during reception of the transmission signal of the signal presence period transmitted from the reception circuit through the transmission line.

The present invention relates to a system for transmitting video, voice and control signals on a multiplex bi-directional transmission basis in both directions at the same time between two video appliances, e.g., between a television camera (which will be referred merely as the camera, hereinafter) and a unit for controlling the camera, i.e., camera control unit (CCU) (which unit will be referred merely as the CCU, hereinafter).
When it is desired to connect the camera to the CCU to attain multiplex bi-directional transmission of video, voice and control signals therebetween for example, it has been conventionally well known to use a triplex coaxial cable (which will be referred to as the cable, hereinafter) called TRIAX cable to transmit these signals on a frequency division multiplex communication basis. An example of the above system is shown in FIG. 1, in which 3 sorts of video signals R, G and B and 4 sorts of voice signals A1, A2, A3 and A4 generated at a camera 100 are transmitted from the camera 100 to a CCU 200, while a monitoring video signal M generated at the CCU 200, a voice signal A5, a control signal D for controlling the operation of the camera 100 and so on are transmitted from the CCU 200 to the camera 100.
In order to transmit a plurality of signals in two ways through a single transmission line or cable 7, different frequency bands are assigned respectively exclusively to these signals so that the carriers of the signals having the different frequency bands are subjected to amplitude modification (AM), as shown in FIG. 2. This results in that, due to the provision of a filter in the camera 100 or CCU 200, these signals appearing on the cable 7 at the same time can be separated from each other on the side of the camera 100 or CCU 200 without interfering with each other at their all components.

Digital video signal multiplex transmission system


A method for determining degrees of freedom of an object, and in particular, to a device for determining up to six degrees of freedom of a head mount display and a handle. A first camera is attached to a head mount display and senses an optically modulated target. The first camera's video output signal is processed with a digital computer to determine the position and orientation of the head mount display. A second camera is attached to a head mount display and senses an optically modulated target attached to a handle. The second camera's video output signal is processed with a digital computer to determine the position and orientation of the handle.

Many virtual reality applications and computer games include means for inputting positional information to the computer. As virtual reality and computer games become more sophisticated, the need for a computer input peripheral operating in three dimensions increases. Applications include computer aided design, computer simulations, virtual reality, games, and the like. In three dimensions, an object's location and orientation is completely specified by six parameters (known as degrees of freedom, or sometimes degrees of motion). Three of the parameters relate to the translational position of the object relative to an origin (and are normally called X, Y, and Z) while the other three relate to the orientation of the object relative to reference direction vectors and/or the object itself (and are often called yaw, pitch, and roll). Devices which convey this information to a computer are known as trackers (or position trackers). In virtual reality applications, a tracker is typically attached to a head mount display (HMD) to allow the computer to track the position of the user's head in space. This positional information is used to update the computer generated scene presented to the user in the HMD. Another tracking device is incorporated in or attached to a handle or pistol grip. The computer uses position information from the handle tracking device for uses including tracking the position of a virtual "gun" for video games and for manipulation of virtual objects.
While a variety of equipment to convey three dimensional degrees of freedom to a computer are known, each has serious drawbacks which are addressed by the present invention.
A mechanical device for determining six degrees of freedom is described in U.S. Pat. No. 5,230,623. This device, and similar devices, consists of a complex series of articulated arms, where the position of the object (in this case a pointer) is calculated by analyzing the position of each of the joints connecting the arms. This type of system is cumbersome to operate because of the severe restriction in movements (due to the so-called gimbal-lock phenomenon) and range, which is limited by the length of the arms. Very high accuracy is required on the measurement of each joint's angle, as any errors are greatly magnified by the length of the arms. Additionally, flexure or play in the arms or joints contributes to inaccuracy. Another disadvantage is that the pointer is mechanically connected to an arm, and can not fly freely through space.
Another known method of computing three dimensional degrees of freedom uses accelerometers and rate sensors placed orthogonally in a hand held device such as those described in U.S. Pat. Nos. 5,181,181, and 5,128,671. These devices only provide relative, not absolute, position information, and as such must be recalibrated to a known location with each use. Additionally, these devices use a twice integrated function of the accelerometer output to determine position, which is extremely sensitive to an output offset error from the accelerometer. Position error due to sensor offset is proportional to the square of the operating time.
Electromagnetic devices typically use a series of three source coils (one for each axis) generating a magnetic field using time or frequency division multiplexing. A corresponding set of three detector coils move relative to the source coils. The output from these coils is analyzed by computer to provide position and orientation information. These systems are subject to electrical and magnetic interference, and interference from nearby ferrous metal bodies. They also have severe limitations on range, position, and orientation accuracy.

Method and apparatus for determining position and orientation


A refrigeration apparatus containing a thermostat, adapted for use in a food storage compartment potentially containing a flammable gas, includes a thermostat and an enclosure forming a chamber configured to house the thermostat. The enclosure has two umbrella-type check valves configured to permit gas to pass into the chamber or out of the chamber when a predetermined pressure differential exists between the chamber and the food storage compartment. The enclosure forms a seal with the thermostat so that gas only passes through the check valves.

Thermostats typically used in refrigerators have electrical contacts that "make" and "break" contact to complete an electrical circuit to energize the refrigerator compressor motor or power relay. There may be a small arc or spark produced by the thermostat contacts by this process. This is not a problem in refrigerators that use FREON or other non-explosive refrigeration gasses. However, some countries are presently moving in a direction to use propane, butane, or other hydrocarbon-based gas in lieu of FREON for a variety of reasons.
One such reason to eliminate the use of FREON gas is that FREON gas is a chloroflurocarbon-type gas (CFCs) and is known to be detrimental to the environment. Public pressure and governmental regulations have been increasing the demand on industry to use "environmentally-friendly" products. As a consequence, refrigeration appliances have been developed in which the refrigerant fluid is made up of gases or a mixture of gases that do not significantly impact the environment adversely. However, such relatively environmentally friendly gases, such as propane and butane, have the undesirable characteristic of being flammable.
In refrigeration systems using such combustible gases, some of the gas could be present in the closed food storage compartment where the thermostat assembly is located. This may pose a risk of explosion if the gas is ignited. Depending upon the propane or butane to oxygen ratio, a spark produced within the thermostat could cause ignition of the gases within the refrigeration compartment. Such a situation is dangerous and unacceptable. Additionally, various safety specifications, such as IEC 79-15, dictate that certain precautions must be taken and that certain design criteria must be followed when explosive gasses may be present.
In specifying temperature settings for vapor operated refrigeration thermostats, it is known to include a standard barometric pressure at which the specified temperatures apply. When performing actual temperature setting measurements, the actual barometric pressure is also measured, and the temperature settings are corrected to the specified standard barometric pressure.
When the thermostat mechanism is placed inside a sealed enclosure, measurement of the pressure inside the sealed enclosure is no longer possible. Thus, measurement of the setting temperatures now vary as a result of variation in atmospheric pressure at the time that the enclosure was sealed, and also vary as a result of measuring the temperature settings of the thermostat having a body temperature different than the body temperature at the time of sealing. The result is an apparent increase in setting temperature variation and different mean setting temperatures. This causes temperature setting measurement correlation problems between the thermostat manufacturer and the customer which incorporates the thermostat into a refrigeration unit.

Refrigeration thermostat with controlled pressure equalization


A method and system for distributing a fluid onto a selected surface having a sprinkler system with a sprinkler head; pumps and piping for distributing the fluid through the sprinkler system; where the sprinkler system has a first and second aperture and where the dispensing fluid for winter application includes calcium acetate or potassium acetate.

Many homeowners and businesses have sprinkler systems for irrigating lawns, vegetation, plants, vegetables and the like. Many of these irrigation systems comprise of a sprinkler system which is located underground having a plurality of sprinkler heads that pop up under the pressure of water applied by a pumping system. These sprinkler system and others have controllers which in many cases comprise of programmable units or computers to apply water on a desired area or surface at a selected interval. In other cases, sensors are utilized to monitor environmental conditions and activate the sprinkler systems at a selected interval under selected conditions.
Furthermore, there have been a variety of de-icing systems that have heretofore been designed in order to attempt to clear selected surfaces from the accumulation of snow or ice. Such systems are utilized so as to minimize human effort which may in certain circumstances lead to health conditions due to the age of the individual trying to clear the snow or ice. In other cases the de-icing systems are relied upon to quickly respond to conditions such as clearing of paths, driveways, sidewalks, parking lots, airplane runways, bridges, or the like.
For example, U.S. Published Application US2006/0204647 A1 describes a system and method to deice or remove snow or ice accumulated on a surface which comprises a weather sensor, control means, a compressor containing a de-icing agent, a heater to heat the agent, a second de-icing agent stored in a second storage tank to communicate with a compressor, and means for distributing the de-icing agent through one or more zones, each zone including a sprinkler head and piping. When air temperature is below freezing and humidity exceeds 99% a control means causes a de-icing agent to be heated and the heated agent distributed through a zone. The second agent is distributed through the zone, and then the pressurized gas purges the zone of residual agents.
Moreoever, U.S. Pat. No. 7,588,195 illustrates a de-icing apparatus which may include a reservoir containing a de-icing agent, a distribution network, and at least a first nozzle for de-icing a surface, such as a sidewalk. In one embodiment at least one or more of the reservoir or distribution network is located underground and at least one or more of the reservoir, distribution network, and nozzle is operatively fixed with respect to the associated surface. The apparatus may further be provided with pumping means for pumping the de-icing agent through the apparatus.
U.S. Pat. No. 7,658,333 relates to an irrigation system comprising sprinkler heads with an electronically configurable spray pattern, moisture sensors and a controller. Based on input signals from the moisture sensors, the controller dynamically configures the spray pattern of the sprinkler head to allow more water to fall on areas that need to be watered and less water to fall on areas that do not require additional water.
Furthermore, U.S. Pat. No. 4,676,918 relates to an antifreeze composition and preparation for making surfaces free of snow and ice comprising an amount of 20-90% by weight of a waste concentrate of alcohol distilling industry, having a dry substance content of 200-750 g/kg in admixture with 20-80% by weight of water and optionally with additives.
It is an object of this invention to provide an improved de-icing system and method and sprinkler heads then compared with the prior art. It is also an object of this invention to provide a system and method having a dual summer and winter operation as required during selected time intervals.
There is a need to reduce manual labour, snow blowers, tractors, trucks, ploughs, shovels and brooms and other equipment commonly used in the removal of ice and snow from residential and pubic sidewalks, roads, highways, driveways, parking lots, shopping, centres, bridges, airport runways and flat roofs. There is a need to reduce the need for hoses, portable water sprinklers and carrying utensils in relation to fertilizing and watering plants and lawns. It is an object of the invention to reduce injuries, heart attacks, back pain, damage to roads and property and CO2 emissions.
It is an aspect of this invention to provide a method of distributing a fluid onto a selected surface comprising: a sprinkler system having a sprinkler head, a network of pipes and pumps for distributing the fluid through the sprinkler system; a sprinkler head having a first and second aperture. The first aperture comprises a mist aperture and the second aperture comprises a directional spray aperture. In one embodiment, the distributed fluid comprises calcium acetate or potassium acetate to be applied to a first surface comprising a driveway, asphalt, sidewalk, parking lot, plane runway, bridge, or the like. The de-icing fluid is directed and distributed to the first selected surface for a selected time interval.
In another embodiment, the distributed fluid comprises liquid fertilizing agent which is distributed onto a second selected surface such as a garden, lawn or the like.
It is another aspect of this invention to provide a system for distributing a de-icing fluid onto a first selected surface comprising: a sprinkler system having a plurality of sprinkler heads, a network of underground pipes and pumps for distributing the fluid through the sprinkler system; the de-icing fluid comprising potassium acetate or calcium magnesium acetate. In one embodiment, the system includes a controller for controlling the distribution of the de-icing fluid at a selected time interval. In another embodiment, the controller comprises a digital programmer and the system includes sensors for sensing environmental conditions and varying the distribution of de-icing fluid at each of the plurality of sprinkler heads to provide a desired distribution.
In another embodiment, the system is operable to convert to apply a summer nutrient fluid comprising of nitrogen, potassium and phosphorous to a second selected surface.
Yet another aspect of this invention comprises a process for melting and reducing the accumulation of snow and ice on a first selected surface which comprises a digital controlled winter weather outdoor sprinkler system using a fluid comprising of potassium acetate and calcium magnesium acetate under pressure, which process can be converted to apply a summer nutrient solution comprising of nitrogen and potassium and phosphorous to lawns, gardens, plants and the like.
These and other objects and features of the invention shall now be described in relation to the following drawings.


A lithographic apparatus having an illumination system for providing a projection beam of radiation; an article support member for supporting an article to be placed in a beam path of the projection beam of radiation on the article support; and a clamp for providing a clamping pressure for clamping the article against the article support during projection. The article support member includes a section that is trimmed for locally adjusting a clamping pressure.

1. Field of the Invention
The present invention relates to a lithographic apparatus, an article support member, and a method for manufacturing a device. More specifically, one embodiment of the invention relates to a lithographic apparatus having an illumination system for providing a projection beam of radiation; an article support member for supporting an article to be placed in a beam path of the projection beam of radiation on the article support; and a clamp for providing a clamping pressure for clamping the article against the article support during projection.
2. Description of the Related Art
A lithographic apparatus is a machine that applies a desired pattern onto a target portion of a substrate. Lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In that circumstance, a patterning device or patterning structure, such as a mask, may be used to generate a circuit pattern corresponding to an individual layer of the IC, and this pattern can be imaged onto a target portion (e.g. comprising part of, one or several dies) on a substrate (e.g. a silicon wafer) that has a layer of radiation-sensitive material (resist). In general, a single substrate will contain a network of adjacent target portions that are successively exposed. Known lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at one time, and so-called scanners, in which each target portion is irradiated by scanning the pattern through the projection beam in a given direction (the "scanning"-direction) while synchronously scanning the substrate parallel or anti-parallel to this direction.
Designing article supports such as wafer tables or reticle supports in a lithographic system is a necessary process. Conventionally, the article support is provided with protrusions that are arranged to improve the flatness of the substrate. European patent application EP0947884 describes a lithographic apparatus having a substrate holder wherein protrusions are arranged to improve the flatness of the substrate in a vacuum clamped wafer support table. These protrusions have a general diameter of 0.5 mm and are located generally at a distance of 3 mm away from each other and thereby form a bed of supporting members that support the substrate. For an electrostatic clamp, typically, the height of the protrusions lies in the range 1 μm–15 μm. For a vacuum clamp, these protrusions generally have a height of 100 μm. Due to the relative large spaces in between the protrusions, contaminations possibly present generally do not form an obstruction for the flatness of the substrate, since these will be lying in between the protrusions and will not lift the substrate locally.
In the context of this application, the said "article" may be any of the above mentioned terms wafer, reticle, mask, or substrate, more specifically terms such as a substrate to be processed in manufacturing devices employing lithographic projection techniques; or a lithographic projection mask or mask blank in a lithographic projection apparatus, a mask handling apparatus such as mask inspection or cleaning apparatus, or a mask manufacturing apparatus or any other article or optical element that is clamped in the light path of the radiation system.
From the above identified patent application it is known that the design of these protrusions requires careful choice of design parameters that are influential to the pressure applied to the wafer, and thus its vertical position and flatness. Other publications such as EP1241706 are related to an electrostatic wafer support table, wherein a substrate is electrostatically clamped to the wafer support table. Known electrostatic clamps are usually provided with an arrangement arranged to use a backfill gas, which is used to fill the spaces formed between the protrusions, a base plate that forms a ground layer for supporting the protrusions and the backside of a substrate clamped by the substrate holder. Such a backfill gas enhances the heat transfer capability from the substrate to the substrate holder. In order not to spill this backfill a wall may be present having a contour that generally follows the contour of the substrate and which provides, when the substrate contacts the substrate holder, a confining environment is provided that restricts gas-outflow. It was found that, also for electrostatic clamping configurations, especially for electrostatic clamping configurations where a hard rim is present for confining a backfill gas to the back of a substrate to be irradiated, the wafer tends to be supported unevenly, especially near the boundary of the protrusion configuration, due to the termination of support near the boundary edge. This may cause, depending on the degree of overhang, an upward lifting of the wafer or a downward "sagging" near the edges, which may result in unacceptable imaging quality. Hence, here, also the design parameters can change substantially the amount of levelness of an article to be supported by the article support.
However, design choices are limited by manufacturing tolerances. It has been found that manufacturing tolerances can be a problem to meet the specifications of particular article support designs, in particular relating to vacuum seal position, burl position and stiffness, and di-electricum thicknesses.

Lithographic apparatus, article support member, and method


The computer programmable system and program product include first program instructions for actively driving a first imbalance mass concentration rotor and a second imbalance mass concentration rotor at a vibration canceling rotation frequency while controlling the rotational position of the first imbalance mass concentration and the second imbalance mass concentration to produce a rotating net force vector to inhibit periodic vibrations. The program product includes second program instructions to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration during a starting stopping rotation speed less than the vibration canceling rotation frequency. The system includes a fault mode control protocol for controlling a rotation of the rotors during a sensed failure of the rotating assembly vibration control system.

Helicopter vibrations are particularly troublesome in that they can cause fatigue and wear on the equipment and occupants in the aircraft. In vehicles such as helicopters, vibrations are particularly problematic in that they can damage the actual structure and components that make up the vehicle in addition to the contents of the vehicle.
There is a need for a computer program system and computer instruction execution method of accurately and economically controlling rotating vehicle assembly vibrations. There is a need for a system and method of accurately controlling rotary wing vibrations in an efficient manner. There is a need for a method of controlling vibrations in a helicopter rotating hub assembly so that the vibrations are efficiently minimized. There is a need for a robust system of controlling vibrations with a vibration control system so that the vibrations are efficiently minimized. There is a need for a method/system for electronic control of problematic helicopter vibrations.

Computer system and program product for controlling vibrations


A method of grind hardening a workpiece is provided. The method may include securing the workpiece in a workpiece retainer and a grind tool in a tool retainer, rotating the grind tool in a first angular direction at a first angular speed, controlling the workpiece and tool retainers such that the grind tool engages the workpiece, and controlling the workpiece and tool retainers such that the grind tool is guided along a grinding track of the workpiece. The grind tool may engage and/or disengage the workpiece at portions of sacrificial material disposed thereon. Coolant and cleaning nozzles may be provided and controlled such that at least a portion of the coolant from the coolant nozzle is diverted to the cleaning nozzle in a manner which reduces heat dissipation, improves thermal efficiency of the grind hardening and reduces loading of the grind tool.

Technical Field
The present disclosure generally relates to computed numerically controlled machine tools, and more particularly, to methods and apparatus for performing grind hardening processes using computer controlled machine tools.
Description of the Related Art
Computed Numerically Controlled (CNC) machine tools are generally known for forming metal and wooden parts. Such machine tools include lathes, milling machines, grinding machines, and other tool types. More recently, machining centers have been developed, which provide a single machine having multiple tool types and capable of performing multiple different machining processes. Machining centers may generally include one or more tool retainers, such as spindle retainers and turret retainers holding one or more tools, and a workpiece retainer, such as a pair of chucks. The workpiece retainer may be stationary or move (in translation and/or rotation) while a tool is brought into contact with the workpiece, thereby removing material from the workpiece.
Often, a metal workpiece which has been soft-machined using such machine centers, must undergo a hardening process prior to a grinding or other finishing process. A hardening process typically involves heating, annealing and cooling the metal within a relatively short period of time. Conventional hardening processes use induction coils, gas burners, or the like, in order to heat the metal to temperatures above respective critical temperatures, and subsequently use cooling baths, or the like, to cool the metal to room temperature. The heating and cooling steps of such hardening processes, however, consume significant amounts of energy and resources. Furthermore, the added handling required to remove the soft-machined workpiece from the machine center, harden the workpiece, and reinstall the hardened workpiece back into the machine center for finishing consumes added time and excess labor.
More recent hardening procedures have combined the grinding and hardening processes into a single grind hardening process to overcome some of the drawbacks associated with more conventional hardening techniques. Specifically, the friction that is generated between the grind tool and the workpiece during the grinding process is used to heat the surfaces of the workpiece to temperatures sufficient for hardening. The relatively cooler core of the workpiece then serves as a heat sink which rapidly absorbs the heat from the surface layer to ultimately produce hardening results that are comparable to those of more conventional methods. Although such schemes may provide some improvements, due to the geometry of the grind wheel as well as the manner in which the grind wheel engages a workpiece, currently existing grind hardening processes are unable to provide uniform or adequately controlled hardened surfaces. Furthermore, existing schemes lack measures for monitoring a hardening process, and thus, are unable to more finely control the degree of hardness that is applied to a work surface. Currently existing schemes also use an excess of energy and resources in order to cool or clean the contact area between the grind tool and the workpiece during a grind hardening process.


A method of aligning microwires includes modifying the microwires so they are more responsive to a magnetic field. The method also includes using a magnetic field so as to magnetically align the microwires. The method can further include capturing the microwires in a solid support structure that retains the longitudinal alignment of the microwires when the magnetic field is not applied to the microwires.

Microwires are a class of long and narrow materials and can have lengths on the order of 100 microns and aspect ratios on the order of 10 . These microwires are employed in a variety of different applications such as solar cells and solar fuels generators. These applications use arrays of microwires where the microwires are longitudinally aligned. These arrays are generally fabricated growing using the Vapor-Liquid-Solid (VLS) method of Chemical Vapor Deposition (CVD). However, this method is expensive and cannot be efficiently scaled for use in large-scale production. As a result, there is a need for a method of generating structures having longitudinally aligned microwires.