A fresh donor tissue valve isolation annulus size comprising a handle and trigger or crank knob manipulated by the user moves a movable probe into proximity with a stationary probe so that the probes can be inserted into the tissue valve lumen. The user releases the trigger or crank, and a biasing mechanism urges the movable probe away from the stationary probe until the resistance presented by the valve annulus equals the biasing force. A gage coupled to the movable probe displays a measure of the valve annulus diameter as a function of the distance that the movable probe moves away from the stationary probe until restrained from further movement by the fresh tissue valve annulus.

Implantable heart valve prostheses have been used to replace various diseased or damaged native or natural aortic valves, mitral (bicuspic) valves, pulmonic valves and tricuspid valves of the heart. Prosthetic heart valves can be used to replace any of these naturally occurring valves, although repair or replacement of the aortic or mitral valves is most common because they reside in the left heart chambers responsible for maintaining cardiac output of oxygenated blood. The aortic and mitral valves are most frequently replaced due to heart disease, congenital defects or injury. The mitral valve controls the flow of blood between the left atrium and the left ventricle and the aortic valve controls the blood flow from the left ventricle into the aorta. Generally, the known heart valve prostheses are either bioprostheses or mechanical heart valve prostheses.
Modern mechanical heart valve prostheses are typically formed of an annular valve seat in a relatively rigid valve body and one or more occluding disk or pair of leaflets that is movable between a closed, seated position in the annular valve seat and an open position in a prescribed range of motion. Such mechanical heart valves are formed of blood compatible, non-thrombogenic materials, typically currently comprising pyrolytic carbon and titanium. Hinge mechanisms and/or pivoting guides entrap and prescribe the range of motion of the disk or leaflets between open and closed positions. Exemplary bi-leaflet mechanical heart valves are disclosed in commonly assigned U.S. Pat. Nos. 4,935,030 and 6,139,575 and in U.S. Pat. Nos. 6,176,877 and 6,217,611.
The bioprostheses or "tissue valves" or "xenografts" (hereafter "tissue valves") are generally made of suitable donor heart valves harvested from an animal and treated with a preservative and fabricated as described further herein. The most widely used tissue valves include some form of stationary metal or plastic frame or synthetic support, referred to as a "stent", although so-called "stentless" tissue valves are available. The most common tissue valves are constructed using an intact, multi-leaflet, harvested donor tissue valve, or using separate leaflets cut from bovine (cow) pericardium, for example. The most common intact donor tissue valve used for stented and stentless valves is the porcine (pig) aortic valve, although valves from other animals (e.g., equine or marsupial donors) have been used. The present invention is not limited to the preparation of porcine valves, though existing tissue valves on the market are nearly exclusively made from porcine valves, and thus the description herein will focus on such tissue valves.
Exemplary tissue valves formed of swine valve leaflets mounted to struts of a stent are those disclosed in U.S. Pat. Nos. 4,680,031, 4,892,541, and 5,032,128 as well as the MEDTRONIC® Hancock II® and Mosaic® stented tissue valves. Some prosthetic tissue valves are formed from treated integral swine valve leaflets and valve annulus structure, e.g., the MEDTRONIC® Freestyle® stentless aortic root bioprostheses.
Mechanical and tissue valves have advantages and disadvantages. By their very nature, mechanical heart valves have metal or plastic surfaces exposed to the blood flow, which remain thrombogenic even long time after their implantation by major surgery. The opening and closing of mechanical heart valve occluders can damage blood elements and trigger a coagulant cascade. Blood flow disturbances in certain mechanical valves are also believed to aggravate blood coagulation. Therefore, patients having such mechanical heart valves can avoid potentially life threatening embolus formation only by taking anti-thrombogenic or anti-coagulant medication on a regular basis. Porcine tissue valves include three cusps or leaflets of a heart valve excised from pigs and preserved by treatment with glutaraldehyde. The preserved porcine tissue is thrombogenic, and therefore, the human patient takes anti-thrombogenic or anti-coagulant medication at least a period of time after the surgical implantation of a tissue valve. Valve leaflet opening and closing characteristics and blood flow past open tissue leaflets of tissue valves can be superior to those afforded by mechanical valves. However, tissue leaflets can become calcified over time distorting the leaflet shape and ultimately leading to failure of the tissue leaflets to fully close or open. Proposals have been advanced to form mechanical heart valve prostheses from flexible, anti-thrombogenic, polymeric sheets or fabrics that are resistant to calcification mounted to stents to function like stented tissue valves also been proposed as exemplified by U.S. Pat. No. 5,562,729. However, calcification and tear issues of polymeric materials remain to be solved before a polymeric valve can be realized.
Such mechanical valves and tissue valves are intended to be sutured to peripheral tissue of a natural heart valve orifice (the "valvar rim") after surgical removal of damaged or diseased natural valve structure from the patient's heart. Modern prosthetic heart valves are typically supplied with a sewing or suturing ring surrounding the valve body or stent that is to be sutured by the surgeon to the valvar rim. Suturing rings typically comprise a fabric strip made of synthetic fiber that is biologically inert and does not deteriorate over time in the body, such as polytetrafluoroethylene (e.g., "Teflon PTFE") or polyester (e.g., "Dacron"), that is woven having interstices permeable to tissue ingrowth. The valve body or stent is typically circular or ring shaped having an outer surface or sidewall shaped to fit with an inner sidewall of the suturing ring. In some cases, the suturing ring fabric is shaped to extend outward to provide a flattened collar or skirt that can be applied against and sutured to the valvar rim, as shown for example in U.S. Pat. No. 3,997,923.
To assure a proper fit, the patient's tissue annulus must be "sized" to indicate the size of the mechanical valve or tissue valve to be implanted in the valvar rim. In particular, proper fit of the annular valve body within the tissue annulus of the excised native valve is required. Typically, a set of sizers is supplied by the prosthetic heart valve manufacturer corresponding to the different sizes of available prosthetic heart valves. The surgeon inserts the sizers through the prepared annulus defined by the valvar rim to determine which corresponding prosthetic heart valve will best fit the valvar rim. The surgeon usually must attempt to size the annulus several times with one or more sizers of different diameters until the best fit is recognized.
Conventional sizers for measuring the human valve annulus typically comprise a series of incrementally sized cylindrical elements marked with the corresponding outside diameter in mm. Most sizer sets include cylindrical elements that range from a low of 19 mm to a high of 33 mm, in 2 mm increments, and a common handle for manipulating the sizers. Some sizers for measuring the human valve annulus are shaped, or include flanges or other stepped features to also provide a measurement of the aortic root adjacent to the annulus. The aortic root is that part of the valve anatomy between the annulus and the convex sinuses of the ascending aorta, and has a generally scalloped appearance with the valve leaflets being attached along alternating arcuate cusps and upstanding commissures around its border. In any event, the primary measurement derived from conventional surgical sizers is the annulus diameter determined by finding which sizer fits properly in the annulus based on tactile feedback.
A different approach to sizing the prepared valvar rim annulus is set forth in U.S. Pat. No. 6,110,200. The '200 patent discloses a single sizing apparatus that can be adjusted through a range of diameters to measure an anatomical tissue annulus. The apparatus includes an elongated support member having a proximal end and a distal end. An operator actuated movable member is joined to the proximal end of the elongated support member while an adjustable member is joined to the distal end of the elongated support member. The adjustable member has a reference axis and an outer curved surface selectively positionable in response to the operator actuated member. In particular, the outer curved surface can be selectively positioned between an inner position proximate the reference axis and an outer position spaced apart from the reference axis.
In one embodiment, a fluid passageway extends from the proximal end to the distal end an elongated support member, and an operator actuated movable member is joined to the proximal end of the elongated support member for providing fluid through the passageway to the distal end. An expandable, balloon-like member mounted to the distal end of the elongated support member receives the fluid. The expandable member having a reference axis and a substantially continuous outer curved surface disposed about the reference axis and selectively positionable in response to fluid provided by the operator actuated movable member between an inner position proximate the reference axis and an outer position spaced apart from the reference axis.
Preferably, an indicator is mounted to the elongated support member for determining a dimension of the outer curved surface. The indicator includes indicia representative of selected radial distances of the outer curved surface from the reference axis. A detent mechanism rotates with the shaft and selectively engages releasable stop surfaces on the indicator. The stop surfaces correspond to the various indicia on the indicator. The stop surfaces hold the shaft in each of the selected angular positions, which in turn, maintains the outer curved surface at each selected radial distance from the reference axis.
Thus, it is necessary to manufacture and distribute prosthetic heart valves in a variety of sizes to fit the sized annulus of a prepared valvar rim. The tissue valve manufacturer must have a supply of fresh donor heart valves from animals from which the range of tissue valves are fabricated. A typical prosthetic valve fabrication process for manufacturing porcine tissue valves in a variety of sizes is described in U.S. Pat. No. 6,458,155, for example.
As set forth in the '155 patent, fresh porcine hearts are first harvested in a certified slaughterhouse, weighed, and sorted into various valve size ranges by either estimating the annulus by eye, based on the flattened aortic width, or by estimating valve orifice size from heart weight. Of course, this correlation is a very rough estimate, with actual valve annulus sizes differing quite a bit within similarly sized porcine hearts. The aortic valve and surrounding tissue including a section of the pulmonary artery (hereinafter termed the "aortic valve isolation") is then severed from the porcine heart.
A batch of aortic valve isolations are packed in ice and shipped from the slaughterhouse to the prosthetic valve manufacturing facility. At the manufacturing facility, the aortic valve isolation is further sorted by valve size by technicians trained to estimate such valve size using their fingers. That is, the orifice diameter of the aortic valve annulus is estimated by insertion of one or more fingers through the inflow end of the aortic valve isolation. Because of the rough nature of the heart weight to valve size estimation, a large proportion of valves are rejected at this stage, resulting in wasted inventory and shipping costs.
The accepted aortic valve isolations are then trimmed and chemically fixed to render the donor tissue valves biologically inert for implantation in human patients. The trimming procedure typically involves cutting away the pulmonary artery and surrounding muscle tissue from the inflow end of the aortic valve isolation. The remaining donor tissue valve is generally tubular having a small amount of tissue on the inflow side of the annulus and the internal leaflets enclosed and protected by the tubular ascending aorta.
Chemical fixation may be accomplished using a variety of techniques and chemicals, though the most common procedure used involves supporting the tubular tissue valve element on at least the ascending aorta or outflow portion with a fixation insert, immersing the assembly in a bath of fixing solution (e.g., glutaraldehyde), and either flowing fixing solution through the tissue valve element or maintaining a predetermined pressure differential across the leaflets during the fixation process. See, for example, U.S. Pat. No. 4,372,743, which describes maintaining a low pressure differential across the leaflets of between 1-4 mm Hg.
The use of fixation inserts is also quite effective in shaping the tissue valve during the fixation process. For example, U.S. Pat. No. 5,197,979 describes inserts having three outwardly convex regions for shaping the tissue valve sinuses. More recently, U.S. Pat. No. 6,001,126 discloses inserts having a plurality of pinholes in the two convex regions corresponding to the coronary sinuses that enable coronary artery shaping plugs or mandrels to be mounted thereon. Whichever type of insert is used, the ultimate size of the fixed tissue valve is influenced, at least in the sinus regions, by the insert. Preferably, the relative size of the annulus and sinus regions is identical to the human aortic tissue valve being replaced. It is therefore very important to begin with a donor tissue valve having an accurately sized annulus.
The fixation process causes some shrinkage in the donor tissue valve. Therefore, the sizing of the annulus of the fresh donor tissue valve provides only an estimate of the annulus size of the fixed tissue valve. The amount of shrinkage depends on the chemicals used, the duration of fixation, the pressure differentials maintained within the tissue valve annulus during fixing, the temperature during fixing, and other less significant factors. Because of these variables, the annulus of fixed porcine aortic tissue valves are sized once again using a caliper and/or a sizing stent to sort the tissue valves into mounting sizes.
It is thus apparent that an accurate and reliable means for estimating, from the fresh donor tissue valve, the annulus size of a fixed xenograft tissue valve annulus is needed to increase tissue valve yield and quality, and reduce expense.
The above-referenced '155 patent discloses an apparatus for sizing fresh donor heart tissue valves that have a lumen and an inwardly directed tissue valve annulus within the lumen. The apparatus includes a sizing member having an axially extending, preferably conical, sizing portion with a forward end adapted to insert within the lumen of the donor heart tissue valve. The sizing portion increases in size along an axis from the forward end such that a region on the exterior thereof eventually contacts the tissue valve annulus upon continued insertion of the sizing portion within the lumen. A measuring bracket connects to the sizing member and has a scale portion spaced from and generally aligned with the sizing portion, the scale portion providing markings indicating the annulus size of the donor heart tissue valve relative to the position of the donor heart tissue valve on the sizing portion. The measuring bracket may include a mounting portion generally perpendicular to the scale portion and including a through hole into which the sizing portion fits. The markings are desirably supplemented with numerical indicators of tissue valve size, either in terms of tissue valve diameter in millimeters or as non-dimensional numbers in conjunction with a separate chart to correlate the numerical indicators with tissue valve size. The markings may be calibrated for fresh donor tissue valves from a particular geographic supply source.
The method of use of the sizing member disclosed in the above-referenced '155 patent includes inserting the forward end of the sizing portion into the donor heart tissue valve lumen, and halting the insertion at a predetermined resistance to further insertion. After halting further insertion of the sizing portion into the lumen, the tissue valve annulus size is determined based on the distance that the sizing portion has been inserted. In a preferred embodiment, the sizer further includes a measuring bracket connected thereto having a scale portion spaced from and generally aligned with the sizing portion. The tissue valve size is determined by observing the position of the donor heart tissue valve with respect to the scale portion of the measuring bracket.
A number of problems can arise in using the sizing member of the '155 patent. The user must select the tissue valve isolation and insert the tip of the conical sizing member into the valve lumen, pushed the tissue valve isolation over the conical surface as far as the valve annulus will go, to read the indicia on the surface, and to then pull the tissue valve isolation back off the conical sizing member. In doing so, care must be taken to avoid stretching the tissue valve annulus unduly. It is necessary for the user to keep the conical surface clean so that the conical sizing member can be easily inserted into the tissue valve lumen to the correct extent and then be easily removed from the tissue valve lumen. The estimation of the tissue valve lumen size is somewhat subjective for these reasons and because the tissue valve isolation covers the indicia on the conical surface at the tissue valve lumen.
It would also be difficult to use the conical probe within the lumens of harvested donor tissue valve isolations that include a long, curved aortic root as is used in preparation of certain tissue valve prostheses.

Methods and apparatus for sizing fresh donor heart valves


A method and apparatus is presented. The apparatus comprises a parts library, a database, and a parts management system. The parts library is configured to store a plurality of part definition files. The database is configured to store entries identifying a printing of parts using the plurality of part definition files. The parts management system is configured to receive a request for a part definition file in the parts library, identify the part definition file in the plurality of part definition files in the parts library, receive an indication of a printing of a part using the part definition file, and store an entry identifying the printing of the part using the part definition file in the database.

1. Field
The present disclosure relates generally to the manufacture of parts. More particularly, the present disclosure relates to the three dimensional printing of parts. Yet more particularly, the present disclosure relates to a method and apparatus for authorizing the three dimensional printing of parts.
2. Background
Modern aircraft contain a plurality of different parts. Aircraft manufacturers have each part design certified under airworthiness standards and other requirements of the Federal Aviation Administration (FAA). A certification for a part is specific to that part's specifications such as dimensions, shape, and material specifications.
During the lifetime of an aircraft, parts may be replaced. In order to meet demand for replacement parts, aircraft manufacturers may keep an inventory of parts on hand. A client may request parts from the aircraft manufacturer when a replacement part is desired. However, receiving requested parts from the aircraft manufacturer may take an undesirable amount of time for a client. Some clients may keep an inventory of parts on hand to avoid waiting an undesirable amount of time. However, storing an inventory of extra parts either at an aircraft manufacturer or at a client may use an undesirable amount of resources.
Three dimensional printing is a process of making a solid object of virtually any shape from a part definition file. Three dimensional printing is an additive process where successive layers of material are laid down. Three dimensional printing may be performed with a variety of different materials such as polymers, plasters, metals, and metal alloys. Three dimensional printing may allow on-demand manufacture of desired parts.
Therefore, it would be desirable to have a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues.


The present invention provides a power generation device for exercise equipment including a fixing seat, a swinging seat and a power generating component. The joint and positioning end of the swinging seat has a hinge connection part to be connected with the fixing seat, and the power generating component is configured on a preset position on the swinging seat. A magnetic lifting component is configured to cause magnetic repelling between the swinging end of the swinging seat and the fixing seat, so that the swinging end of the swinging seat can be elastically lifted. The driven part of the power generating component will constantly maintain tight contact with the flywheel of exercise equipment. The magnetic lifting component can exert a magnetic repulsing function without elastic fatigue and solid abrasion.

1. Field of the Invention
The present invention relates generally to a power generation device for exercise equipment, and more particularly to an innovative device with a magnetic support component to cause magnetic repellence between the swinging seat and the fixing seat for a supporting effect in a stepper exercise machine.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
In prior art power generation devices for exercise equipment, a driven wheel is configured to contact a flywheel, which is driven by friction. However, in the prior art, after a certain exposure to friction between the driven wheel and the flywheel, the surface of the driven wheel will be inevitably worn out, and the outer diameter will be reduced. Consequently, the flywheel can no longer be driven by the driven wheel, and the power generating function will disappear.
In consideration of the above problem, the industry has developed an improvement that can maintain constant tight contact between the driven wheel and the flywheel of the exercise equipment through the pull or push of a spring component. However, in actual usage of such prior art structures, it is still found that the spring component, no matter its action is pull or push, will quickly lose its elasticity due to tiredness after repeatedly squeezing or traction, and consequently affecting the support effect of the driven wheel. Hence, there is a problem of insufficient durability and a short life span.
Thus, to overcome the aforementioned problems of the prior art, it would be an advancement in the art to provide an improved structure that can significantly improve efficacy.
Therefore, the inventor has provided the present invention of practicability after deliberate design and evaluation based on years of experience in the production, development and design of related products.

Power generation device for exercise equipment


An add/drop multiplex includes a matrix switch, the drop side of which is connected via buses to respective time slot assignment function circuits which are interconnected by at least one bus capable of transferring traffic between the add and the drop functions of the multiplex.

1. Field of the Invention
This invention relates to an improvement in add-drop multiplexes, known also as add-drop multiplexer, also known in Europe as drop-and-insert multiplexes. Such multiplexes are a particular form of combined multiplexer/demultiplexer for digital signals, optimised for the low cost insertion or extraction of a proportion of the "through" traffic capacity of the multiplex.
2. Description of the Related Art
A digital multiplex combines multiple digital signals streams into a composite stream of digits, each of the digits in the original streams conventionally being allocated to a unique timeslot in the frame structure of the composite stream. Following recognition of the inserted frame start signal at the demultiplexer, the demultiplexer separates the multiple signals so as to restore them to their original form.
In a terminal digital multiplex, all of the capacity of the composite stream is accessible in the form of multiple individual streams; by contrast, in an add-drop multiplex this is commonly not the case, and there are other differences which are outlined below.
It is gradually becoming a common feature of add-drop multiplexes that they incorporate a matrix switch. This switch has the ability to control the routing of traffic in small increments, each of which is a small fraction of the total traffic passing through the multiplex.
Where this fraction is particularly small, the switch has a correspondingly high complexity, because of the large number of such increments to be manipulated, and this invention relates to a proposed simplification of the switch.

Bus bypassing matrix switch in add-drop multiplexer


A control device includes: an acquisition portion that acquires, from an information processing apparatus, pairing information corresponding to at least one of electronic devices among a plurality of pieces of pairing information corresponding to the respective electronic devices, the pairing information being used in order that the electronic devices connected to each other via a wireless network perform pairing; and an output portion that outputs the pairing information corresponding to the at least one of the electronic devices to the at least one of the electronic devices by using a non-contact system different from the wireless network.

Electronic devices which are connected to each other by a wireless network, such as a wireless LAN (Local Area Network) and ZigBee, are used. Since the electronic devices can transmit and receive data via the wireless network, cables for transmitting and receiving the data are not needed. Movement of the electronic devices is easy. In order to connect the electronic devices to the wireless network, pairing, such as sharing of a secret key for encryption and/or setting of addresses, is performed between the electronic devices. For the pairing, pairing information including addresses is delivered between the electronic devices. Performing delivery of the pairing information between the electronic devices through a remote control is known. Infrared data communication is used for transmission and reception of the pairing information between the remote control and the electronic device (e.g. see Japanese National Publication of International Patent Application No. 2006-526933 and Japanese Laid-open Patent Publication No. 2004-200887).


An exposure device that sequentially projects and repeatedly transfers a predetermined pattern formed on a reticule onto wafers via an optical projection system, the exposure device including a movement unit that positions a current shot region on a wafer in the focal position of the optical projection system, a detection unit that detects tilting on an exposure surface of the current shot region with respect to an image plane of the optical projection system, and a plurality of first piezoelectric elements that correct the tilting on the current shot region with respect to the optical axis, based upon the detection results of the detection unit, so that the exposure surface of the current shot region will substantially match the image plane.

1. Field of the Invention
The present invention relates to an exposure device and an exposure method.
2. Background Information
A stepper is employed as an exposure device, and serves to form circuit patterns on a semiconductor substrate (such as a silicon wafer and the like) in semiconductor devices, liquid crystal display devices, and the like. The stepper is a device that exposes a plurality of circuit patterns onto a substrate by projecting and repeatedly transferring a reduced version of a circuit pattern formed on a reticule onto the substrate via an optical projection system.
FIG. 9A is a schematic diagram of a conventional stepper used with silicon wafers, and FIG. 9B is an enlarged view of a support portion included in the stepper shown in FIG. 9A. The stepper shown in FIGS. 9A and 9B includes a condenser lens 2 that restricts the light from a light source 1, a reticule 3, an optical projection system 4, a position adjustment unit 5, and a wafer holder 12. A wafer 15 is mounted on the wafer holder 12. The light source 1, the condenser lens 2, the reticule 3, and the optical projection system 4 are sequentially disposed along an optical axis 17 of the light source 1 and perpendicular therewith. The reticule 3 includes a circuit pattern that will be formed on the wafer 15, and receives light from the condenser lens 2. The light that passes through the circuit pattern is projected at a reduced size onto the wafer 15 by means of the optical projection system 4, and is imaged onto the current shot region on the wafer 15.
The position adjustment unit 5 includes an X stage 6, a Y stage 7, a Z stage 8, a θ stage 9, and a leveling stage 10 that are disposed along the optical axis of the optical projections system 4, moves the wafer 15 by means of a motor drive, and positions the current shot region on the wafer 15 in the focal position of the optical projection system 4. Here, the X stage 6 moves the wafer 15 along the X axis of FIG. 9A that is in a plane perpendicular to the optical axis 17, the Y stage 7 moves the wafer 15 along the Y axis of FIG. 9A that is perpendicular to the optical axis 17 and the X axis, the Z stage 8 moves the wafer 15 along the Z axis of FIG. 9A that is parallel to the optical axis 17, and the θ stage 9 rotates the wafer 15 in a plane perpendicular to the optical axis 17. In addition, the leveling stage 10 includes three support portions 11a, 11b, and 11c. The lengths of the support portions 11a–11c are adjusted by means of the motor drive, and, as shown in FIGS. 10 and 11, thereby allow correction of any distortion of the subject image in the image plane (i.e., distortion of the circuit pattern) caused by warping/uneven surfaces located on the surface of the wafer 15 and/or any aberration or distortion in the condenser lens 2 or the lenses inside the optical projection system 4.
FIGS. 10A and 10B illustrate the operation of the leveling stage 10 and the support portions 11 in response to a warp/uneven surface located on the wafer 15. In FIG. 10A, the image plane A from the optical projection system 4 and the exposure surface of the wafer 15 do not match because there is a warp/uneven surfaces located on the wafer 15. Accordingly, as shown in FIG. 10B, the lengths of the support portions 11a–11c on the leveling stage 10 are adjusted to tilt the wafer holder 12 and the wafer 15 so that the image plane A and the exposure surface of the wafer 15 will match.
In addition, FIGS. 11A and 11B illustrate the operation of the leveling stage 10 and the support portions 111 in response to distortion of the subject image in the image plane A caused by an aberration or distortion in one or more of the lenses of the stepper. In FIG. 11A, the image plane A and the exposure surface of the wafer 15 do not match, thereby producing a distortion in the subject image on the exposure surface. Accordingly, as shown in FIG. 11B, the lengths of the support portions 11a–11c on the leveling stage 10 are adjusted to tilt the wafer holder 12 and the wafer 15 so that the image plane A and the exposure surface of the wafer 15 will match.
However, with the stepper disclosed in FIGS. 9A and 9B, the speed at which the lengths of the support portions 11a–11c on the leveling stage 10 are adjusted by the motor drive is slow. Thus, it will take time to correct any distortion of the subject image in the image plane caused by warping/uneven surfaces located on the wafer 15 and/or aberration or distortion in one or more of the lenses, and thus the time needed for the entire exposure process will increase. In addition, electric power consumption costs will increase because the support portions 11a–11c are operated by the motor drive.
Furthermore, it is difficult to perform localized corrections because tilting on the wafer 15 is corrected by adjusting the tilt of the wafer holder 12 by means of the support portions 11a–11c. In addition, even if warping/uneven surfaces located on the wafer 15 and/or aberration or distortion in the lenses is localized, the operational range of the support portions 11a–11c will increase because it will be necessary to adjust the tilting on the entire wafer 15 by means of the support portions 11a–11c. Thus, there will be a large amount of waste with respect to the amount of time the support portions 11a–11c are driven and the amount of electric power consumed therefor. Furthermore, warping/uneven surfaces on the wafer 15 caused by the presence of a foreign substance between the wafer holder 12 and the rear surface of the wafer 15 cannot be corrected by adjusting the tilt of the wafer holder 12.
In view of the above, there exists a need for an exposure device and an exposure method which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.


In a fuel cell power generation system for use with a fuel gas which is prepared by desulfurizing a raw fuel material such as naphtha, LPG, town gas, or the like and then, processing it by steam reforming reaction and thus, consists mainly of hydrogen or a process of producing the fuel gas, the desulfurization of the raw fuel material is implemented using a copper/zinc desulfurizing agent. As a result of the desulfurization, the raw fuel material is desulfurized at a higher level and the deterioration of a steam reforming catalyst employed is prevented. Accordingly, steady long-run operation of the fuel cell will be ensured. Also, upon the steam reforming reaction, the S/C (the mole number of steam per one mole of carbon in a raw fuel material) is reduced and thus, the concentration of hydrogen in the fuel gas will be increased providing an improvement in the efficiency of power generation.

Fuel cells have been known as systems for converting chemical energy derived from raw fuel materials directly to electrical energy. A typical fuel cell consists mainly of a pair of opposing porous electrodes--a fuel electrode and an oxidant electrode--separated by an electrolyte layer holding an electrolyte, in which electricity is generated between the two electrodes by an electrochemical reaction triggered when a fuel, e.g. hydrogen, is directly fed to the back of the fuel electrode and an oxidant, e.g. air, is fed to the back of the oxidant electrode. In operation, amounts of electrical energy are produced at a high conversion rate while both the fuel and the oxidant are supplied continuously. Besides, because of their favorable characteristics to energy saving and environmental conservation, the fuel cells have been studied for practical use.
In such a fuel cell, the fuel (an anode active substance) for feeding to the fuel electrode is commonly hydrogen which is supplied in the form of a fuel gas, containing hydrogen as a primary component, converted by steam reforming reaction from a raw fuel material such as methane, ethane, propane, butane, natural gas, naphtha, kerosine, gas oil, liquefied petroleum gas (LPG), town gas, etc.
It is understood that a sulfur component in the raw fuel material poisons a steam reforming catalyst (e.g. Ru catalyst or Ni catalyst). If the raw fuel material contains, for example, 0.1 ppm of sulfur, about 90% of the surface of a Ru or Ni catalyst will be covered with sulfur in a short time thus losing catalytic activity. Hence, the raw fuel material is initially desulfurized prior to steam reforming process.
Accordingly, a conventional fuel cell power generation system comprises: a desulfurizing unit for desulfurizing a raw fuel material; a fuel reforming section for converting the desulfurized raw fuel material by steam reforming into a fuel gas containing a primary component of hydrogen which is in turn fed to the fuel electrode of a fuel cell; an oxidant feeding section for feeding an amount of oxygen (air) to the oxidant electrode of the fuel cell; and a fuel cell unit for generating electricity by an electrochemical reaction between hydrogen from the fuel gas and oxygen. The desulfurization of a raw fuel material prior to steam reforming process is commonly carried out by hydrogenating desulfurization in which organic sulfur in the raw fuel material is decomposed by hydrogenolysis, for example, at 350.degree. to 400.degree. C. in the presence of Ni-Mo or Co-Mo catalyst and then, resultant H.sub.2 S is removed by adsorption on ZnO at 350.degree. to 400.degree. C.
FIG. 1 is a system diagram showing an outline of substantial arrangement of a typical fuel cell power generation system (PC18) which contains a desulfurizing unit for performing the hydrogenating desulfurization and a steam reforming unit. As shown, a raw fuel material 1 is mixed with a fuel gas, which contains hydrogen as a primary component, introduced from a carbon monoxide shift converter 5, described later, and fed to a hydrogenating desulfurization reactor 2a. The hydrogenating desulfurization reactor 2a contains, from entrance, a hydrogenation layer filled with e.g. Ni-Mo or Co-Mo catalyst and an adsorption layer filled with an adsorption desulfurizing agent such as ZnO. The raw fuel material 1 mixed with a portion of the fuel gas derived from the carbon monoxide shift converter 5 is heated up to 350.degree. to 400.degree. C. by a heater (not shown) and then, hydrogenated at the hydrogenation layer so that a sulfur component of the raw fuel material is converted into H.sub.2 S, which is in turn adsorbed into the adsorption layer, for desulfurization of the same. The desulfurized raw fuel material 1 is mixed with steam in a mixer 3 and transferred to a steam reformer 4 where it is converted by steam reforming reaction into a fuel gas containing hydrogen as a primary component. The resultant fuel gas is then transferred to the carbon monoxide shift converter 5, filled with shift catalyst, where carbon monoxide is converted into hydrogen and carbon dioxide: this procedure is needed for preventing poisoning by carbon monoxide upon the catalyst (e.g. platinum catalyst) of a fuel electrode 7 and also, enhancing efficiency in the conversion to hydrogen. Most of the fuel gas from the carbon monoxide shift converter 5 is supplied as a fuel to the fuel electrode 7 in a phosphoric acid electrolyte fuel cell unit 6 while a small portion of the same is returned to the hydrogenating desulfurization reactor 2a. Hydrogen in the fuel gas introduced into the fuel electrode unit 6 then reacts in electrochemical process with oxygen in the air 9 which is supplied by a compressor 8 into an oxidant electrode 10. As a result of the reaction, a portion of the fuel gas is consumed while a by-product of water is created, and electrical energy is produced which is almost equivalent to a current provided to an electric load 19.
The fuel gas discharged from the fuel electrode 7 is transferred to a burner 11 in the steam reformer 4 where it is mixed with a portion of the air 9 supplied from the compressor 8 and burned for heating the steam reformer 4. A resultant exhaust gas containing steam is transferred from the burner 11 via a heat exchanger 12 to a condenser 13 where it is separated into water and gas. The separated gas is discharged. The condensed water is added to a water supply line 14 which is fed water via a water supply pump 15 and a cooling water pump 16 to the fuel cell unit 6 for cooling purpose. The cooling water is circulated from the fuel cell 6 via a heat exchanger 17 to a gas/water separator 18 for separation into steam and water. The separated water is then returned across the cooling water pump 16 to the fuel cell unit 6 for recirculation and the separated steam is transferred to the mixer 3, where it is mixed with the raw fuel material 1, and then, fed to the steam reformer 4 for use in the steam reforming reaction.
The aforementioned prior art fuel cell power generation system has however some disadvantages to be overcome. At the hydrogenating desulfurization step for desulfurizing the raw fuel material, if organic sulfur contained in the raw fuel material is excessive in amount or hard to be decomposed, e.g. thiophene, it will be slipped off without being decomposed and fail to be adsorbed by ZnO thus passing away. This phenomenon is also unavoidable when the raw fuel material is a gaseous fuel such as a town gas which contains an odorant of hardly decomposable, non-adsorbable organic sulfur such as dimethylsulfide. The hydrogenating desulfurization catalyst is tended to provide catalytic activity at a temperature of more than 350.degree. C. and will hardly react in response to a change in the fuel cell load. Also, the catalyst requires an extra heating device and a flow controller for activation with no warming-up period thus will rarely be reduced in the size.
During the adsorption desulfurization, chemical equilibrium is involved as expressed by: EQU ZnO+H.sub.2 S.revreaction.ZnS+H.sub.2 O EQU ZnO+COS.revreaction.ZnS+CO.sub.2.
Hence, the amount of H.sub.2 S and COS remains not less than a certain value. Particularly, this will be emphasized while H.sub.2 O and CO.sub.2 are present. Also, if the desulfurizing section in the entire system is unstable during startup and/or shutdown procedures, sulfur may escape from the adsorption desulfurization catalyst thus increasing the concentration of sulfur in the raw fuel material. For preventive purpose, the desulfurization of the prior art is executed in which the raw fuel material contains surfur in the level of several ppm to 0.1 ppm after refinement. Accordingly, poisoning of the steam reforming catalyst can not be fully suppressed and constant long-run operation of fuel cell will be hardly ensured.
In the prior art fuel cell power generation system, the fuel gas fed to the fuel electrode consists mainly of: hydrogen, a reaction product generated by steam reforming reaction; carbon dioxide generated by carbon monoxide shift reaction; and surplus steam which remains unused during the steam reforming reaction. When a partial pressure of hydrogen in the fuel gas is increased, the efficiency of power generation in the fuel cell becomes improved. It is however difficult to reduce the amount of carbon dioxide in the fuel gas which is released by the carbon monoxide shift reaction. Hence, the task of increasing the hydrogen partial pressure and improving the power generation efficiency in the fuel cell is embodied by decreasing S/C (mole numbers of steam per carbon mole in hydrocarbon in the raw fuel material) during the steam reforming reaction and also, the surplus amount of steam. However, when the S/C is reduced, the concentration of carbon monoxide, a product of steam reforming reaction, in the fuel gas increases even after shift reaction in the carbon monooxide shift converter. The carbon monoxide s now going to poison the catalyst of the fuel electrode in the fuel cell, particularly a platinum catalyst which is commonly employed in a phosphoric acid electrolyte fuel cell operable at a lower temperature, which is in turn deteriorated in properties. In other words, using a fuel gas containing a high concentration of carbon monoxide causes a decrease in the power generation efficiency of a fuel cell.
As described above, the steam reforming catalyst is poisoned by sulfur in the raw fuel material and its catalytic activity is declined, whereby deposition of carbon onto the catalyst surface will be stimulated. For prevention of this action, the S/C is increased in the prior art. If the S/C is decreased, the catalyst activity declines and carbon will be deposited on the catalyst surface causing increase of differential pressure and simultaneously, the raw fuel material itself will be fed to the fuel cell while being incompletely decomposed, preventing the fuel cell to perform a long-run operation without difficulties. Also, the catalyst installed in the steam reformer has to be increased in amount for compensation of a loss caused by the sulfur poisoning of catalyst. As the result, the steam reformer remains not decreased in the size and the overall size of the fuel cell can hardly be minimized.
As understood, although lower S/C in the fuel cell power generation intends to increases the hydrogen partial pressure in the fuel gas, it is difficult to reduce the S/C because the aforementioned drawbacks ar no more negligible. For example, the S/C cannot be less than 3.5 when Ni catalyst is applied as the steam reforming catalyst nor below 2.5 when Ru catalyst, which provides a higher catalytic activity, is applied. The S/C is commonly adjusted for steam reforming reaction to more than 3 with the Ru catalyst and 4 with the Ni catalyst. Thus, the amount of steam in the fuel gas will be increased preventing rise in the partial pressure of hydrogen.
The present invention is directed, for the purpose of elimination of the foregoing disadvantages attribute to the prior art, to an improved fuel cell power generation system in which a raw fuel material is desulfurized at a high enough degree to prevent the deterioration of steam reforming catalyst even if the S/C is low so that steady long-run operation can be ensured and a process of producing a fuel gas which is high in the partial pressure of hydrogen.


Quasi-achromatic multi-element lens(es) which are precisely mounted with respect to one another in a tubular mounting fixture, and the application thereof in focusing, (and optionally re-colliminating), a spectroscopic electromagnetic beam into a very small, chromatically relatively undispersed, area spot on a material system.

The practice of ellipsometry is well established as a non-destructive approach to determining characteristics of material systems, and can be applied in real time process control. The topic is generally well described in a number of publication, one such publication being a review paper by Collins, titled "Automatic Rotating Element Ellipsometers: Calibration, Operation and Real-Time Applications", Rev. Sci. Instrum, 61(8) (1990).
In general, modern practice of ellipsometry typically involves causing a spectroscopic beam of electromagnetic radiation, in an imposed, known, state of polarization, to interact with a material system at one or more angle(s) of incidence with respect to a normal to a surface thereof, in a plane of incidence. (Note, a plane of incidence contains both a normal to a surface of an investigated material system and the locus of said beam of electromagnetic radiation). Changes in the polarization state of said beam of electromagnetic radiation which occur as a result of said interaction with said material system are indicative of the structure and composition of said material system. The practice of ellipsometry utilizes said changes in polarization state by proposing a mathematical model of the ellipsometer system and the material system investigated by use thereof, obtaining experimental data by application of the ellipsometer system, and applying square error reducing mathematical regression, (typically), to the end that parameters in the mathematical model which characterize the material system are evaluated so that the obtained experimental data, and values calculated by use of the mathematical model have a "best match" relationship.
A typical goal in ellipsometry is to obtain, for each wavelength in, and angle of incidence of said beam of electromagnetic radiation caused to interact with a material system, material system characterizing PSI and DELTA values, (where PSI is related to a change in a ratio of magnitudes of orthogonal components rp/rs in said beam of electromagnetic radiation, and wherein DELTA is related to a phase shift entered between said orthogonal components rp and rs, caused by interaction with said material system. Said PSI and DELTA are defined by:ρ=rp/rs=Tan(Ψ)exp(iΔ).
As alluded to, the practice of ellipsometry requires that a mathematical model be derived and provided for a material system and for the ellipsometer system being applied. In that light it must be appreciated that an ellipsometer system which is applied to investigate a material system is, generally, sequentially comprised of:                a. a Source of a beam electromagnetic radiation;        b. a Polarizer element;        c. optionally a compensator element;        d. (additional element(s) such as lens(es), beam directing means, and/or windows such as in vacuum chambers);        e. a material system;        f. (additional element(s) such as lens(es), beam directing means, and/or windows such as in vacuum chambers);        g. optionally a compensator element;        h. an Analyzer element; and        i. a Detector System.Each of said components b.–i. must be accurately represented by a mathematical model of the ellipsometer system along with a vector which represents a beam of electromagnetic radiation provided from said source of a beam electromagnetic radiation, Identified in a. above). (Note that elements (a–d) can be referred to a Polarization State Generator (PSG), and elements (f–i) as a Polarization State Detector (PSD)).
Various ellipsometer configurations provide that a Polarizer, Analyzer and/or Compensator(s) can be rotated during data acquisition, and are describe variously as Rotating Polarizer (RPE), Rotating Analyzer (RAE) and Rotating Compensator (RCE) Ellipsometer Systems.
Where an ellipsometer system is applied to investigate a small region of a material system present, it must be appreciated that the beam of electromagnetic radiation can be convergently entered thereto through an input lens, and, optionally, exit via a re-collimating output lens. It is also possible to have only a collimating lens after the sample. In effect this adds said input, and/or output lens(es) as elements in the ellipsometer system as "additional elements", (eg. identified in d. and f. above), which additional elements must be accounted for in the mathematical model. If this is not done, material system representing parameters determined by application of the ellipsometer system and mathematical regression, will have the effects of said input, (and output), lenses at least partially correlated thereinto, much as if the input and, (output lenses), were integrally a part of the material system.
It is emphasized that where two sequentially adjacent elements in an ellipsometer system are held in a static position with respect to one another while experimental ellipsometric data is acquired, said two sequentially adjacent elements generally appear to be a single element. Hence, a beam directing element adjacent to a lens can appear indistinguishable from said lens as regards the overall effect of said combination of elements. In that light it is to be understood that present input and output lenses are normally structurally fixedly positioned and are not rotatable with respect to a material system present in use, thus preventing breaking correlation between parameters in equations for sequentially adjacent input and output lenses and an investigated material system by an element rotation technique. While correlation of parameters in mathematical equations which describe the effects of groupings of elements, (such as a compensator and an optional element(s)), can be tolerable, correlation between parameters in the mathematical model of an investigated material system and other elements in the ellipsometer system must be broken to allow obtaining accurate material system representing PSI and DELTA values, emphasis added. That is to say that correlation between parameters in equations in a mathematical model which describe the effects of a stationary compensator and a sequentially next located lens element, (eg. correllation between effects of elements c. and d. or between f. and g. identified above), in a beam of electromagnetic radiation might be tolerated to the extent that said correlation does not influence determination of material system describing PSI and DELTA values, but the correlation between parameters in equations which describe the effects of ellipsometer system components (eg. a., b., c., d., f., g., h. and i.), and equations which describe the effects of a present material system (eg. element e. above), absolutely must be broken to allow the ellipsometer system to provide accurate PSI and DELTA values for said material system. Application of ellipsometry to investigation of a material system present can then present a challenge to users of ellipsometer systems in the form of providing a mathematical model for each of an input and output lens, and providing a method by which the effects of said input and output lenses can be separated from the effects of an investigated material system.
One typical approach to overcoming the identified problem, where space considerations are not critical, and where ellipsometer system configuration can be easily modified, is to obtain multiple data sets with an ellipsometer system configured differently during at least two different data set acquisitions. For instance, a data set can be obtained with a material system present and in which a beam of electromagnetic radiation is caused to interact with said material system, and another data set can be obtained with the ellipsometer system configured in a straight-through configuration, where a beam of electromagnetic radiation is caused to pass straight through an ellipsometer system without interacting with a material system. Simultaneous mathematical regression utilizing multiple data sets can allow evaluation of material system characterizing PSI and DELTA values over a range of wavelengths, uncorrelated with present birefringent retardation effects of present input and output lenses. The problem with this approach is that where ellipsometer systems are fit to vacuum chambers for instance, ellipsometer reconfiguration so as to allow acquisition of such multiple data sets can be extremely difficult, if not impossible to carry out.
Another rather obvious solution to the identified problem is to provide input, and output, lenses which are absolutely birefringence-free, and transparent at all electromagnetic beam wavelengths utilized. That is, provide input, and output, lenses which do not attenuate the magnitude of rp or rs orthogonal components, (or at least do not change their ratio, rp/rs), and which also do not enter phase shift between rp or rs orthogonal components when said beam of electromagnetic radiation is caused to pass therethrough. While control of the effect of a lens on a ratio, (rp/rs), of electromagnetic beam orthogonal components can often rather successfully be accomplished by causing a beam of electromagnetic radiation to approach a surface of a lens along essential a normal to a surface thereof, this is not the case regarding phase shift entered between rp and rs orthogonal components of a said beam of electromagnetic radiation caused to pass therethrough. That is, input, and output, lenses can demonstrate "birefringence", in that the rp orthogonal component is "retarded" by a different amount than is the rs orthogonal component when said beam of electromagnetic radiation is caused to pass therethrough. To complicate matters, this "birefringent" effect also varies with wavelength and with stresses which can develop in a lens during use because of temperature and physical changes etc.
As described in Parent application Ser. No. 09/162,217, (which is incorporated herein by reference), controlling stress related change is presently achieved with varying degrees of success, where for instance, windows in a vacuum chamber are subject. Windows provided by BOMCO Inc. are produced with the goal of eliminating birefringence, and are mounted in vacuum chambers using copper gasket seals which help to minimize uneven application of stresses and developed strains thereacross. While some success is achieved via this approach, the BOMCO windows are not "perfect" and do demonstrate some remaining birefringence properties, which can vary in unpredictable ways over a period of usage. In addition, BOMCO windows are expensive, costing on the order of $1000.00 each), and are large in size thereby making adaptation thereof to use in a vacuum chamber difficult at times, particularly in retro-fit scenarios. And, there have been cases where BOMCO windows have broken in use. This is highly undesirable as vacuum chambers are often times caused to contain highly toxic and hazardous materials during, for instance, etching and/or deposition steps required in the fabrication of semiconductor devices. Where vacuum chamber windows are the subject, an alternative to use of the BOMCO windows is to simply use standard vacuum chamber windows, which, while significantly less expensive, demonstrate order of magnitude larger birefringence effects. (Note, BOMCO windows provide birefringent effects on the order of approximately six-tenths (0.6) to two-tenths (0.2) degrees over a range of wavelengths of from four-hundred (400) to seven-hundred-fifty (750) nanometers, whereas standard vacuum windows demonstrate birefringent effects on the order of six (6.0) to three (3.0) degrees over the same range of wavelengths). (Note, birefringent retardation typically follows an approximate inverse wavelength, (eg. 1/wavelength), relationship). However, where standard vacuum chamber windows are utilized, compensation of their effects is required. Similar concerns apply where input and output lenses, and associated ellipsometrically indistinguishable ellipsometer system components are concerned.
A need is thus identified for a method of practicing ellipsometry which enables the breaking of correlation between parameters in equations which describe retardance entered to orthogonal components of a beam of electromagnetic radiation caused to interact with a material system, and parameters in equations which describe birefringent effects on said orthogonal components in said beam of electromagnetic radiation caused by input and output windows of a vacuum chamber, and/or by input and output lenses and/or by electromagnetic beam directing means etc.
Various researchers have previously noted the identified problem, where vacuum chamber windows are the topic, and proposed various first order mathematical model equation correction techniques as solution, which approaches have met with various degrees of success where vacuum chamber input and output windows demonstrate on the order of a maximum of two (2) degrees of birefringence. This, however, leaves the problem unsolved where birefringence approaches six (6.0) degrees, as commonly occurs in standard vacuum chamber windows, and can also occur in lens systems, particularly at wavelengths of four-hundred (400) nanometers and below. Thus is identified a problem to which the present invention calibration methodology applies.
Patents and/or Published Applications which describe the use of multiple element lenses in Ellipsometer and the like systems include:
Applications of Danner et al.:
                EP1 172 642 A2;        JAPAN 2002 2098591 A        U.S. 2002/0024669;Applications:        WO 91/14157;        WO 92/12404 by Rudolf Corp.;        WO 96/18205;        WO 99/02950;Patents:        U.S. Pat. No. 4,671,657 to Calvani et al.;        U.S. Pat. No. 5,166,752 to Spanier et al.;        U.S. Pat. No. 5,349,497 to Morris;        U.S. Pat. No. 5,877,859;        U.S. Pat. No. 5,963,327 to He et al.;        U.S. Pat. No. 5,978,087 to Patterson et al.        Japanese Application H6 (1994)-22332.
Other patents of which the Inventor is aware include those to Woollam et al, U.S. Pat. No. 5,373,359, patent to Johs et al. U.S. Pat. No. 5,666,201 and patent to Green et al., U.S. Pat. No. 5,521,706, and patent to Johs et al., U.S. Pat. No. 5,504,582 are disclosed for general information as they pertain to ellipsometer systems.
Additional Patents of which the Inventor is aware include U.S. Pat. Nos. 5,757,494 and 5,956,145 to Green et al., in which are taught a method for extending the range of Rotating Analyzer/Polarizer ellipsometer systems to allow measurement of DELTA'S near zero (0.0) and one-hundred-eighty (180) degrees, and the extension of modulator element ellipsometers to PSI'S of forty-five (45) degrees. Said patents describes the presence of a variable, transmissive, bi-refringent component which is added, and the application thereof during data acquisition to enable the identified capability.
A patent to Thompson et al. U.S. Pat. No. 5,706,212 teaches a mathematical regression based double fourier series ellipsometer calibration procedure for application, primarily, in calibrating ellipsometers system utilized in infrared wavelength range. Birefringent window-like compensators are described as present in the system thereof, and discussion of correlation of retardations entered by sequentially adjacent elements which do not rotate with respect to one another during data acquisition is described therein.
A patent to Woollam et al, U.S. Pat. No. 5,582,646 is disclosed as it describes obtaining ellipsometic data through windows in a vacuum chamber, utilizing other than a Brewster Angle of Incidence.
Patent to Woollam et al, U.S. Pat. No. 5,373,359, patent to Johs et al. U.S. Pat. No. 5,666,201 and patent to Green et al., U.S. Pat. No. 5,521,706, and patent to Johs et al., U.S. Pat. No. 5,504,582 are disclosed for general information as they pertain to Rotating Analyzer ellipsometer systems. The 359 Patent describes a Rotating Analyzer Ellipsometer (RAE) which can comprise a Collimating Lens prior to the Sample being investigated, but has no Lens after said Sample. While not specifically disclosing a focusing lens before the Sample and no collimating lens thereafter, said 359 Patent does obviate the use of a lens before a sample in an ellipsometer, with no lens after said sample being present.
Patents identified in a Search specifically focused on the use of lenses, preferrably achromatic, in ellipsometry and related systems are:                U.S. Pat. Nos. 5,877,859 and 5,798,837 to Aspnes et al.;        U.S. Pat. No. 5,333,052 to Finarov;        U.S. Pat. No. 5,608,526 to Piwonka-Corle et al.;        U.S. Pat. No. 5,793,480 to Lacy et al.;        U.S. Pat. Nos. 4,636,075 and 4,893,932 to Knollenberg; and        U.S. Pat. No. 4,668,860 to Anthon.
The most relevant patent found is U.S. Pat. No. 5,917,594 to Norton. However, the system disclosed therein utilizes a spherical mirror to focus an electromagnetic beam onto the surface of a sample in the form of a small spot. Said system further develops both reflection and transmission signals via application of reflective means and of reflection and transmission detectors. The somewhat relevant aspect of the 594 Patent system is that a positive lens and a negative meniscus lens are combined and placed into the pathway of the electromagnetic beam prior to its reflection from a focusing spherical mirror. The purpose of doing so is to make the optical system, as a whole, essentially achromatic in the visible wavelength range, and even into the ultraviolet wavelength range. It is further stated that the power of the combined positive lens and negative meniscus lens is preferrably zero. It is noted that, as described elsewhere in this Specification, said 594 Patent lens structure, positioning in the 594 Patent system, and purpose thereof are quite distinct from the present invention lens structure and application to focus a beam of electromagnetic radiation. In particular, note that the 594 Patent lens is not applied to directly focus and/or recollimate a beam of electromagnetic radiation onto a sample system, as do the lenses in the present invention. And, while the present invention could utilize a meniscus lens in an embodiment thereof, the 594 Patent specifically requires and employs a negative meniscus lens to correct for spherical aberations caused by off-axis reflection from a spherical mirror, in combination with a positive lens to correct for achromatic aberation introduced by said negative meniscus lens. Further, the present invention system does not require reflection means be present in the path of an electromagnetic beam after its passage through the focusing lens thereof and prior to interacting with a sample system, as does the system in the 594 patent wherein a focusing spherical mirror is functionally required.
A patent to He et al., U.S. Pat. No. 5,963,327 is disclosed as it describes an ellipsometer system which enables providing a polarized beam of electromagnetic radiation at an oblique angle-of-incidence to a sample system in a small spot area.
A patent to Johs et al., U.S. Pat. No. 5,872,630 is disclosed as it describes an ellipsometer system in which an analyzer and polarizer are maintained in a fixed in position during data acquisition, while a compensator is caused to continuously rotate.
Patent to Dill et al., U.S. Pat. No. 4,953,232 is disclosed as it describes a rotating compensator ellipsometer system.
Patents co-owned with this application, which patents Claim various Compensator Designs recited in Claims herein, and which patents are incorporated hereinto by reference are:                U.S. Pat. No. 5,946,098 to Johs et al.;        U.S. Pat. No. 5,963,325 to Johs et al.;        U.S. Pat. No. 6,084,674 to Johs et al.;        U.S. Pat. No. 6,084,675 to Herzinger et al.;        U.S. Pat. No. 6,100,981 to Johs et al.;        U.S. Pat. No. 6,118,537 to Johs et al.;        U.S. Pat. No. 6,141,102 to Johs et al.Patents cited in examination of said patents included U.S. Pat. No. 4,556,292 to Mathyssek et al. and U.S. Pat. No. 5,475,525 to Tournois et al.
A patent to Bjork et al., U.S. Pat. No. 4,647,207 is disclosed as it describes an ellipsometer system which has provision for sequentially positioning a plurality of reflective polarization state modifiers in a beam of electromagnetic radiation. While said 207 Patent mentions investigating a sample system in a transmission mode, no mention or suggestion is found for utilizing a plurality of transmitting polarization state modifiers, emphasis added. Patent Nos. 4,210,401; 4,332,476 and 4,355,903 are also identified as being cited in the 207 Patent. It is noted that systems as disclosed in these patents, (particularly in the 476 Patent), which utilize reflection from an element to modify a polarization state can, that if such an element is an essential duplicate of an investigated sample and is rotated ninety degrees therefrom, then the effect of the polarization state modifying element on the electromagnetic beam effect is extinguished by the sample.
Patents to Rosencwaig et al., U.S. Pat. Nos. 4,750,822 and 5,595,406 are also identified as they describe systems which impinge electromagnetic beams onto sample systems at oblique angles of incidence. The 406 Patent provides for use of multiple wavelengths and multiple angles of incidence. For similar reasons patent U.S. Pat. No. 5,042,951 to Gold et al. is also disclosed.
A patent to Osterberg, U.S. Pat. No. 2,700,918 describes a microscope with variable means for increasing the visibility of optical images, partially comprised of discrete bi-refringent plates which can be positioned in the pathway between an eyepiece and an observed object. Other patents identified in a Search which identified said 918 Patent are U.S. Pat. No. 3,183,763 to Koester; U.S. Pat. No. 4,105,338 to Kuroha; U.S. Pat. No. 3,992,104 to Watanabe and a Russian Patent, No. SU 1518728. Said other patents are not believed to be particularly relevant, however.
A patent, U.S. Pat. No. 5,329,357 to Bernoux et al. is also identified as it Claims use of fiber optics to carry electromagnetic radiation to and from an ellipsometer system which has at least one polarizer or analyzer which rotates during data acquisition. It is noted that if both the polarizer and analyzer are stationary during data acquisition that this patent is not controlling where electromagnetic radiation carrying fiber optics are present.
A patent to Chen et al., U.S. Pat. No. 5,581,350, is disclosed as it describes a method for regression calibration of ellipsometers which is very much similar to that disclosed earlier in an article by Johs.
Patent to Wang. et al., U.S. Pat. No. 6,587,282 is disclosed as it describes a three lens system with specific curvature and spacings associated with each of the lenses.
Patent to Uhrich et al., U.S. Pat. No. 6,829,049 is disclosed as it describes a broadband ellipsometer with all refractive optical system for focusing a probe beam onto a sample.
As present invention preferred practice is to utilize a spectroscopic source of electromagnetic radiation with a relatively flat spectrum over a large range of wavelengths U.S. Pat. No. 6,628,917 to Johs is disclosed. Patents relevant thereto include U.S. Pat. No. 5,179,462 to Kageyama et al. is identified as it provides a sequence of three electromagnetic beam combining dichroic mirrors in an arrangement which produces an output beam of electromagnetic radiation that contains wavelengths from each of four sources of electromagnetic radiation. Each electromagnetic beam combining dichroic mirror is arranged so as to transmit a first input beam of electromagnetic radiation, comprising at least a first wavelength content, therethrough so that it exits a second side of said electromagnetic beam combining dichroic mirror, and to reflect a second beam of electromagnetic radiation, comprising an additional wavelength content, from said second side of said electromagnetic beam combining dichroic mirror in a manner that a single output beam of electromagnetic radiation is formed which contains the wavelength content of both sources of electromagnetic radiation. The sources of electromagnetic radiation are described as lasers in said 462 Patent. Another patent, U.S. Pat. No. 5,296,958 to Roddy et al., describes a similar system which utilizes Thompson Prisms to similarly combine electromagnetic beams for laser source. U.S. Pat. Nos. 4,982,206 and 5,113,279 to Kessler et al. and Hanamoto et al. respectively, describe similar electromagnetic electromagnetic beam combination systems in laser printer and laser beam scanning systems respectively. Another patent, U.S. Pat. No. 3,947,688 to Massey, describes a method of generating tuneable coherent ultraviolet light, comprising use of an electromagnetic electromagnetic beam combining system. A patent to Miller et al., U.S. Pat. No. 5,155,623, describes a system for combining information beams in which a mirror comprising alternating regions of transparent and reflecting regions is utilized to combine transmitted and reflected beams of electromagnetic radiation into a single output beam. A patent to Wright, U.S. Pat. No. 5,002,371 is also mentioned as describing a beam splitter system which operates to separate "P" and "S" orthogonal components in a beam of polarized electromagnetic radiation.
Various papers were also identified as possibly pertinent, and are:
A paper by Johs, titled "Regression Calibration Method for Rotating Element Ellipsometers", Thin Solid Films, 234 (1993) is also disclosed as it describes a mathematical regression based approach to calibrating ellipsometer systems.
A paper by Nijs & Silfhout, titled "systematic and Ramdom Errors in Rotating-Analyzer Ellipsometry", J. Opt. Soc. Am. A., Vol. 5, No. 6, (June 1988), describes a first order mathematical correction factor approach to accounting for window effects in Rotating Analyzer ellipsometers.
A paper by Kleim et al, titled "Systematic Errors in Rotating-Compensator ellipsometry", J. Opt. Soc. Am., Vol 11, No. 9, (setp. 1994) describes first order corrections for imperfections in windows and compensators in Rotating Compensator ellipsometers.
Other papers of interest in the area by Azzam & Bashara include one titled "Unified Analysis of Ellipsometry Errors Due to Imperfect Components Cell-Window Birefringence, and Incorrect Azimuth Angles", J. of the Opt. Soc. Am., Vol 61, No. 5, (May 1971); and one titled "Analysis of Systematic Errors in Rotating-Analyzer Ellipsometers", J. of the Opt. Soc. Am., Vol. 64, No. 11, (November 1974).
Another paper by Straaher et al, titled "The Influence of Cell Window Imperfections on the Calibration and Measured Data of Two Types of Rotating Analyzer Ellipsometers", Surface Sci., North Holland, 96, (1980), describes a graphical method for determining a plane of incidence in the presence of windows with small retardation.
A paper by Jones titled "A New Calculus For The Treatment Of Optical Systems", J.O.S.A., Vol. 31, (July 1941), is also identified as it describes the characterizing of multiple lens elements which separately demonstrate birefringence, as a single lens, (which can demonstrate reduced birefringence).
A paper by Zapien et al., titled: "Real-Time Spectroscopic Ellipsometry from 1.5 to 6.5 eV", Thin Solid Films 364, (2000), shos lenses on both sides of a sample.
A paper by Li titled: "Flying Height Measurementon Al203 Film of a Magnetic Slider", J. or Tribiology, (October 1997) describes a 17 micron spot size achieved by a focusing lens.
A paper by Ghazzawi et al., titled: "Spectroellipsometry Characterization of Directly Bonded Silicon-On-Insulator Structures, Thin Solid Films 233 (1993).
Finally, a paper which is co-authored by inventors herein is titled "In Situ Multi-Wavelength Ellipsometric Control of Thickness and Composition of Bragg Reflector Structures", by Herzinger, Johs, Reich, Carpenter & Van Hove, Mat. Res. Soc. Symp. Proc., Vol. 406, (1996) is also disclosed.
Even in view of relevant prior art, there remains need for ellipsometer systems which comprise input, and optionally output, lenses that allow focusing spectroscopic electromagnetic beams as small spots on material substrates. Further, in view of the inability of first order corrections to break birefringence based correlation between input and/or output lenses and a material system, there remains need for a second order mathematical model equation correction technique which enables breaking correlation between a material system characterizing DELTA and in-plane retardance entered to a beam of electromagnetic radiation by input and output lenses through which said beam of electromagnetic radiation is caused to pass. This is particularly true where lens birefringent retardance exceeds a few degrees. In addition, need remains for a lens system, and the method of its construction, which enables very precise lens characteristics realization
The present invention provides a system with the identified attributes.

This patent is subject to a terminal disclaimer.

Broadband ellipsometer or polarimeter system including at least one multiple element lens


An objective is to provide a compact self-ballasted fluorescent lamp which can reduce occurrence of a short circuit without protecting lead wires extending from each end portion of a spiral arc tube. To achieve the objective, a pair of connection pins is provided on a circuit board of the compact self-ballasted fluorescent lamp, near a periphery of the circuit board so as to oppose another pair of connection pins formed near the periphery. In this way, the pairs of connection pins can be respectively provided directly above the end portions of the spiral arc tube. Thus, lead wires extending from each of the end portions can be connected to a corresponding one of the pairs of connection pins with a relatively short distance. This prevents the lead wires from being in contact with the circuit board, thereby reducing occurrence of a short circuit.

In recent years, compact self-ballasted fluorescent lamps are increasingly used as an alternative for incandescent lamps, which require high power consumption. A compact self-ballasted fluorescent lamp has the same cap as an incandescent lamp and has a fluorescent lamp as a light emitting unit.
The compact self-ballasted fluorescent lamp includes, for example, an arc tube which is formed by spirally winding a glass tube except for end portions, where the end portions are vertically straight (i.e. leg portions), a holder to which the end portions of the arc tube are attached, a drive circuit unit that is attached to the holder and used for driving the arc tube, and a case that houses the drive circuit unit. In addition, two lead wires extend from each of the end portions of the arc tube which are attached to the holder, and are connected to the drive circuit unit. The lead wires are electrically conductive so as to supply power with a filament.
The drive circuit unit is generally formed in such a manner that a capacitor and a transistor are mounted on a printed circuit board. Furthermore, connection pins are provided on the circuit board, so as to connect the lead wires extending from each end portion of the arc tube to the drive circuit unit. The arc tube and the drive circuit unit are electrically connected to each other by winding the lead wires around the connection pins. Alternatively, the connection pins may be formed by wire-like components which are easily bent. In this case, the arc tube and the drive circuit unit are electrically connected to each other in such a manner that the lead wires and the connection pins are twisted together and then soldered. It should be noted here that all of the connection pins are gathered together in an area, for example, aligned in line, on the circuit board in order to achieve smaller circuit and board sizes.
In an attempt to increase an amount of light emission, a new arc tube has recently been developed for self-ballasted fluorescent lamps. In detail, each end portion of the new arc tube is spirally wound in a spiral direction of the arc tube, unlike the above-described conventional arc tube which has end portions which are vertically straight with respect to the holder. The new arc tube is hereinafter referred to as a spiral arc tube.
When comparing this new spiral arc tube with the conventional arc tube, the new spiral arc tube has approximately four spirals, while the conventional arc tube only has approximately three spirals. Thus, the new spiral arc tube has a larger light emission area. As a result, the new spiral arc tube achieves a larger amount of light emission than the conventional arc tube having the leg portions.
In the spiral arc tube, end portions, from each of which two lead wires extend, are positioned so as to oppose each other when seen from above. As describe above, however, the connection pins are gathered together in an area on the circuit board. Accordingly, lead wires extending from at least one of the end portions of the spiral arc tube need to be bent towards the connection pins, in order to be connected to the connection pins on the circuit board. In other words, one of the end portions of the spiral arc tube is more distant from the connection pins than the other end portion is. This poses the following problem specific to the spiral arc tube in which the end portions are spirally wound in the spiral direction. That is, the lead wires extending from one of the end portions which is positioned more distant from the connection pins need to be bent to be connected to the connection pins.
Despite their weakness, lead wires may be bent many times during a manufacturing process of the spiral arc tube. Accordingly, the lead wires tend to break due to a load of the bending. In addition, since the lead wires need to be long enough to be bent, the lead wires tend to easily contact with each other or with other constituents provided on the circuit board. This means that the new spiral arc tube has a high risk that the lead wires short-circuit. To prevent such a short circuit, the lead wires may be covered with an insulative material. However, this is not desirable since the number of constituents and the number of steps in the manufacturing process increase.
When a main light emitting portion of the spiral arc tube is faced downwards, the two lead wires extending from each end portion of the spiral arc tube are pulled up substantially vertically (in a direction along a spiral axis of the spiral arc tube), to be connected to the circuit board which is positioned directly above the spiral arc tube. Here, more short circuits occur between the lead wires, and between the lead wires and the circuit board in the new spiral arc tube than in the conventional arc tube having the leg portions. The reason for this is explained in the following.
In the conventional arc tube having the leg portions, the two lead wires extend from each vertically straight end portion. When such two lead wires are vertically pulled up towards the circuit board, an interval can be horizontally secured between the two lead wires. Thus, the lead wires do not overlap each other, and a short circuit is therefore less likely to occur. In the new spiral arc tube, on the other hand, each end portion is spirally wound in the spiral direction. Here, the two lead wires extending from each end portion are arranged vertically (in a direction along the height of the spiral arc tube, which is the same direction as the direction along the spiral axis of the spiral arc tube). In this case, when the two lead wires are pulled up substantially vertically to be connected to the circuit board, the lead wires are highly likely to overlap each other. Thus, a short circuit tends to occur between the lead wires. To prevent such a short circuit, the lead wires may be covered with an insulative material. However, this is not desirable since the number of constituents and the number of steps in the manufacturing process increase.
Here, the lead wires are fixed to each end portion of the spiral arc tube by pinching. Specifically speaking, each end portion of the spiral arc tube is melted and then pressed, so as to seal and fix the lead wires. However, this pinching method poses the following problem.
When the lead wires are wound around the connection pins provided on the circuit board to establish electrical connection, the lead wires may be strained. If such is the case, the lead wires may break or sealing portions of the spiral arc tube formed by pinching may break due to a tension produced in the lead wires. These breakages are more likely to happen when the connection pins are formed by wire-like components which are easily bent. This is because, in this case, the connection pins and the lead wires are twisted together using a pair of tweezers or the like, and a higher tension tends to be produced in the lead wires.

Compact self-ballasted fluorescent lamp having a circuit board with connection members

Matsushita Electric Industrial Co., Ltd.


Boundary layer control of a structural element in a fluid stream is achieved by the following operations:

The present invention relates in general to aerodynamic and thermal wall boundary layer control of aerodynamic airfoils, in particular to application of such to aircraft, turbo engines and automotive components, especially but not exclusively, to isolated airfoils or fuselage parts, wings, flaps and blades, casing, end walls and liners of turbo engines in order to increase the efficiency and to improve off design performance.
As well known, a boundary layer develops on a wall of a body as soon as it interacts with a flow stream. The aerodynamic performance (lift or loading and drag) and the thermal performance (heat exchange efficiency and working temperature of the component) on nominal and off design conditions depend on the properties and the structure of the boundary layer.
The purpose of boundary layer control, also known as BLC (Boundary Layer Control), is to affect the flow by influencing the structure of the boundary layer, in order to increase the efficiency, the loading and the stage pressure ratio of turbo engines and off design performance of isolated airfoils and bodies.
The main advantages of boundary layer control are:
to delay transition from a laminar to a turbulent boundary layer and thus reduce skin friction and heat transfer;
to prevent or delay boundary layer separation and thereby increase the allowable blade or airfoil loading and range of angles of attack;
to cancel or attenuate flow disturbances in transonic flows.
Such effects can be achieved either by suction of the boundary layer in the regions of interest, or by injection of a working fluid which in turn can be either the same as the main flow or a different one (binary boundary layer).
Boundary layer control by means of a suction method appears, in general, to be the more efficient, but the injection method would be necessary for its use in conjunction with air cooling of turbine blades.
Concerning aircraft or automotive applications, the suction area may be applied either at wing leading edges or at the forward edge of the trailing edge flaps.
Concerning turbo engines, as in the case of isolated airfoils, it is possible to increase the blade loading considerably by the use of boundary layer control. This increase is achieved by prevention or delay of flow separation and the resultant stalling of the blades, and the greatest gain can be obtained if the blades are specially designed for the use of the boundary layer control so as to maintain high loading over most of the blade section. By use of boundary layer control a higher blade loading can be obtained for a given inlet Mach number without exceeding a given Mach number on the blade. In fact the blade can be designed to have a uniformly high Mach number over a larger portion of the upper surface of the blade without flow separation. For the same reason, higher inlet Mach numbers can be used with a given loading without exceeding a given Mach number on the blade. The gain resulting from maintaining a high velocity over a larger portion of the upper surface may be materially reduced, however, by increased velocity over the lower surface as a result of the practical requirement of thicker blades for boundary layer control.
With a conventional blading, the maximum pressure ratio per stage in a multistage compressor is obtained by increasing the axial velocity component and maintaining an essentially symmetrical velocity diagram throughout in order to assure the maximum allowable Mach number on all blade elements. This increase in the axial velocity component can only be obtained by using a sufficiently large taper for the annular passage to more than compensate for the reduction in axial velocity due to the increase in density. The use of taper large enough to maintain constant relative Mach numbers, however, leads to very small passages in the later stages of high pressure-ratio compressors and to high exit velocities. The resultant narrow annular passage tends to produce low efficiencies in the later stages and the high exit velocities either produce large exit losses or require long diffusers. For these reasons, most commercial compressors use much less taper than required to produce constant Mach number and consequently obtain relatively low Mach numbers and pressure ratios in the later stages.
The drop-off in pressure ratio in the later stages due to this decrease in relative Mach number in the wider passage could be prevented, however, if the blade loading could be increased in these stages. Because of the lower Mach numbers, it should be possible to use considerably higher blade loading without obtaining eccessive local Mach numbers on the blades. With conventional blading, however the blade loading is limited by the early stalling of the blades.
The situation can be somewhat improved by the use of blades of high camber, but the gain is limited and the useful range of angles of attack may be reduced. Some further slight increase in pressure ratio can he obtained by the use of solidifies higher than conventional limits of about 1.2, but the gain is generally obtained with some drop in efficiency.
A definitely greater increase in loading and stage pressure ratio should be possible through the use of boundary-layer control on the rotor, stator blades and hub and tip endwalls. The results from isolated airfoils indicate that there should be no difficulty in doubling the loading obtainable without boundary-layer control with a corresponding increase in pressure ratio. The effect of boundary-layer control on the stage efficiency is less easy to evaluate than its effect on stage pressure ratio.
The profile drag-lift ratio should be decreased because of the large increase in lift coefficient possible without boundary-layer separation and because of the decreased profile drag resulting from reduced boundary-layer thickness behind the control slot or porous structure. In addition, some improvement in efficiency might be expected from the fact that, for a given drag-lift ratio, the velocity diagram theoretically most favorable to high profile efficiency (symmetrical diagram with axial velocity equal to one-half rotor-blade velocity), can be approached more closely throughout a multistage compressor when a high stage pressure ratio is obtained by use of boundary-layer control on both rotor and stator blades. The effect is generally obtained with conventional blades by varying the axial velocity to give a constant Mach number entering all blade rows.
The boundary-layer control when applied at critical points of the blades and the casing, allows for positively action on the secondary-flow losses leading to a consistent reduction of the overall losses of the stages.
In addition to the effect on internal aerodynamic efficiency, the power required for supplying the boundary-layer-control air must be considered in evaluating the over-all efficiency of the machine. Because of this pumping loss, it appears desirable to limit the boundary-layer control to the later stages where the largest gains are possible.
In relation to the turbine blade performance, the boundary layer control appears to have useful applications in conjunction with turbine blade cooling.
One of the most effective methods of cooling the trailing edge region of turbine blades is by ejecting cooling air at or near the trailing edge of the blade. This ejected air can be used at the same time as an effective method of boundary layer control for increasing the blade loading and thereby reducing the total blade area for a given power output. The reduction in blade surface may, in turn, be expected to reduce the amount of cooling required to maintain a given blade temperature.
A further application of the BLC has been made for turbines requiring very high specific work with limited rotor blade speed, where negative reaction may be required. The flow through the turbine rotor is then similar to that through a typical compressor rotor and, if the blade loading is to be high, boundary layer control may be required to prevent stalling of the blade. In this case, as in the more usual case, boundary layer control by injection can effectively be used in conjunction with blade cooling.
BLC may well be applied to advantage to fluid dynamic behaviour on the end walls and the casing of the turbo engine and could be successfully used when such an extracted working fluid is in turn routed to cooling systems.
The purpose of the present invention is to define a method of BLC capable of limiting the flow rate fraction used to obtain such an interaction with the wall boundary layer of the component at its maximum extent, while avoiding negative effects on the thermo-mechanical strength and other technological constraints.
According to the present invention, there is provided a method of boundary layer control of a structural element in a fluid stream which includes the following operations:
providing in such structural element at least one region equipped with a microporous structure by an electroforming technique;
having a fluid stream flow through the external surface of the at least one region, inwards or outwards with respect to the environment in which that element is placed.
The structural element is given an intrinsic BLC function by means of a structural porous matrix which carries out the suction or effusion of fluids. In general, this intrinsic function can be obtained by equipping the structural element (airfoil, wing, blade, casing, etc.) with a carrying structure or, alternately with a lining consisting of one or more inserts with micro-holes obtained by means of an electroforming technique.
In addition suction or injection by means of porous walls may be used in transonic flows for the purpose of canceling or attenuating flow disturbances that ordinarily reflect from solid boundaries. With a porous wall, a selected amount of suction can produce cancellation over a range of incident waves and Mach numbers which otherwise would result in reflections. Again, the use of porous material, for a given aerodynamic performance, allows one to limit appreciably the fluid mass flows being supplied.
In practice the invention makes available a BLC method for a structural element, for instance a wing airfoil, which makes use of a microporous structure that, because of the very high density of the micropores, determines a fluid dynamic behaviour of the material which is close to that of a transpiration (sweating) wall.
The fabrication procedure to be used is based on a controlled electrolytic deposition method and is considerably simpler than the traditional fabrication methods (melting, moulding, machine tool processing) for known perforated structures; from the technological point of view, moreover, it makes possible solutions that cannot be obtained by means of these state-of-the-art techniques, a case in point being the possibility of extracting air from the surface of a body in a continuous manner over an extended surface portion.
Even though other and less conventional fabrication techniques employed in this and related sectors for the production of perforated elements intended for boundary layer control functions, includingxe2x80x94among othersxe2x80x94the use of electrically welded or sintered grids or holed plates, make it possible to obtain better results in terms of thermal performance and enhanced resistance to oxidation and corrosion phenomena, they have brought to the fore problems deriving from the clogging of the holes associated with the use of dirty fuels or unfiltered working fluids. A not by any means negligible contribution to this clogging phenomenon is caused by the very rough surface of the perforated elements fabricated in such manner.
The present invention is deemed to be capable of appreciably increasing the performance limits typical of the aforesaid known solutions, first and foremost thanks to the extreme lightness that can be obtained due to the very high surface density of the microholes, secondly thanks to the surface roughness of the material, which micrometer measurements show to be greatly reduced, and finally because the fabrication technique allows for control of the sucked or withdrawn quantities of fluid by locally adjusting the permeability of the wall.
The permeability is a fabrication parameter which can be locally managed through the density of the holes, their diameter and the thickness of the wall. In the specific case of turbo engine blades, this effect may be obtained on either rotor blades or vanes and generally on platforms, end walls and casing.
Basically the principal advantages obtainable by means of the BLC method subject of the invention can be summarized as follows:
the use of a highly porous material leads to a considerable reduction in weight of the component which is employed, thereby reducing stresses;
the use of a highly porous material, as far as the boundary layer control is concerned leads to a considerable increase in the aerodynamic performance of the component;
in a multistage compressor, the number of stages necessary to obtain a given pressure ratio is considerably reduced, thereby dramatically reducing the weight and the length of travel through the machine;
the turbo engine or aircraft/automotive component made of electroformed porous material makes available self carrying structures equipped with the desired location, extent and permeability of effusing regions;
the provision of a porous wall, rather than slits, allow continuous suction or injection to be performed over a large part of the component, leading to a much more effective boundary layer control, and avoiding the jet effect of the usual perforated structures;
the permeability of the wall, required to obtain a desired suction or ejecting effect, can be adjusted according to the design tasks;
the air consumption becomes quite low, thus reducing the work of the supplying compressor;
component boundary layer control can be very readily obtained even in zones that have always been associated with difficulties of a technological nature during manufacture and machining;
in the case of injection, the surface and the body of the component are maintained below the limiting temperatures for viscous flow that lead to a drastic reduction of the strength and structural integrity characteristics;
in case of injection, the solid and liquid particulate matter present in the working fluid is deflected more efficaciously by the surface air film, thus forestalling such phenomena as erosion, deposition and sulphur attack on of the surface;
in the case of injection the surface temperature of the component is lowered below the threshold of hot corrosion and surface oxidation is controlled to within acceptable limits.

Boundary layer control of aerodynamic airfoils

Abstract: providing in such structural element at least one region equipped with micro porous structure by an electroforming technique;

Abstract: having a fluid stream flow through the external surface of the said at least one region, inwards or outwards with respect to the environment in which that element is placed.