In one aspect, a pitch bearing for coupling a rotor blade to a hub of a wind turbine may include an outer race defining a first outer raceway wall. The first outer raceway wall may define a center of curvature. The pitch bearing may also include an inner race defining a first inner raceway wall. The first inner raceway wall may define a center of curvature. In addition, the pitch bearing may include a plurality of roller elements disposed between the first inner and outer raceway walls. Each roller element may define a geometric center. Moreover, the center of curvature for each of the raceway walls may be offset from the geometric center of each roller element.

Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy from wind using known airfoil principles and transmit the kinetic energy through rotational energy to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
To ensure that wind power remains a viable energy source, efforts have been made to increase energy outputs by modifying the size and capacity of wind turbines. One such modification has been to increase the length of the rotor blades. However, as is generally understood, the loading on a rotor blade is a function of blade length, along with wind speed and turbine operating states. Thus, longer rotor blades may be subject to increased loading, particularly when a wind turbine is operating in high-speed wind conditions.
During the operation of a wind turbine, the loads acting on a rotor blade are transmitted through the blade and into the blade root. Thereafter, the loads are transmitted through a pitch bearing disposed at the interface between the rotor blade and the wind turbine hub. Typically, conventional pitch bearings include two rows of balls concentrically disposed within separate raceways defined between inner and outer races, with each ball being configured to contact its corresponding raceway at four separate contact points. Under ideal loading conditions, the loads transmitted through the pitch bearing are distributed evenly over all of the balls. However, due to dynamic loading on the pitch bearing and the difference in stiffness between the hub and the rotor blade, only a small percentage of the balls actually end-up carrying the loads during operation of the wind turbine. As a result, the stresses within such load-carrying balls tend to exceed the design tolerances for the pitch bearing, leading to damage and potential failure of the pitch bearing. Moreover, under dynamic loads, the balls of conventional pitch bearings tend to run up and over the edges of the raceways, resulting in the balls having reduced contact areas with the raceways. This leads to an additional increase in the stresses within the balls, thereby further increasing the potential for damage to the pitch bearing components. Similar issues are also present in conventional yaw bearings for wind turbines.
Accordingly, an improved bearing configuration that addresses one or more of issues described above would be welcomed in the technology.


An underwater local area network for oceanographic observation and data acquisition includes a network node for telemetering data to a final destination and a plurality of sensors each of the sensors having an acoustic modem to transmit information to the network node.

As is known in the art a local area network is a communications network that interconnects of a variety of data communicating devices generally within a physically limited area. Points in a network where communication service is provided, used or where communication channels are interconnected are generally referred to as network nodes or simply nodes. Connected to each of the nodes are devices, generally referred to as stations, which wish to receive and transmit data. The network nodes may be connected using so-called internodal links. Thus, the stations may receive and transmit data via the network nodes and internodal links.
The internodal links between such nodes may be provided as so called point-to-point, multi-point or store-and-forward links. A point-to-point link is a transmission facility that connects only two nodes. A point-to-point transmission facility allows many nodes to communicate with a common node through non-interfering channels. One problem in some point-to-point systems however is that such systems have an internodal acoustic telemetry channel which is a broadcast channel to which all stations coupled to the network have access. This requires a careful orchestration of data packet transmission activity to minimize interference between two packet streams routed through common nodes. Thus, interference from non-neighboring nodes may result.
The so-called multi-point or multi-drop facilities provides service to many nodes that share access to the same transmission facility.
In so called store-and-forward systems, a message from one station is received at a computer acting as a switch and is stored there. After the computer has determined a destination address and an available communication circuit, the message is forwarded to the destination. This method may also be referred to as message switching. In some applications the length of the transmissions handled is limited by breaking up long messages into packets and thus is generally referred to as packet switching.
As is also known, local area networks generally have a set of rules for communicating between nodes generally referred to as a network protocol. In formulating the protocols, the network nodes are generally assumed to have an infinite energy supply and the protocols fail to minimize the number of retransmissions which occur in the network. Furthermore, the round trip propagation time between nodes is generally not a concern in such local area networks. Thus, network protocols are generally formulated to maximize network throughput and minimize expected delay.
In some applications however it may be desirable to have packet transmissions which are power efficient and which minimize the number of retransmissions in a network. This is particularly true in those applications where the network nodes may be provided having non-replaceable non-rechargeable power supplies.


A cover for a shaft having a grip on one end is provided. The cover may include a cap having a base and a protrusion that extends from the base. The cover may further include a sleeve for covering at least a portion of the grip that extends from the cap. The sleeve may have a first end seated against the cap and a second free end. A cover for insertion into a shaft is also provided. Such a cover may include a cap insertable into an end of the shaft and a sleeve that extends from the cap. The sleeve may have a first end attached to the cap and a second free end. A combination of the shaft and the cover is also provided.

The present invention relates to systems and methods for covering grips of shafts, handles and the like, and in particular to extendable and retractable covers for grips used on such shafts, handles and the like that may be exposed to moisture.
Golfers around the world, particularly those in wetter climates such as those found in the United Kingdom or the northwestern part of the United States, often play the already challenging sport of golf in the rain, sometimes from the start to the finish of a round. Players of other sports, such as tennis, hockey, and lacrosse, also often deal with inclement weather or with other sources of moisture that cause the grip on the shaft of their respective main pieces of equipment, i.e., tennis rackets, hockey sticks, and lacrosse sticks, to become slippery.
Golf clubs have a shaft at a proximal end thereof that is grasped by a golfer and a clubhead at a distal end thereof that is used to strike a golf ball. It used to be common for grips to be composed of leather strips wrapped around a proximal end of a shaft nearest the golfer. More common today is the use of grips made of natural or synthetic rubber, or other synthetic or composite materials that are often secured to the shaft by an adhesive, for example. Moreover, grips today have varying degrees of softness or firmness depending on the preferences of the golfer. The choice of grip however can have an impact on a golfer's performance. Softer grips often have poorer performance when wetted, which generally occurs during a rain storm or as a golfer's hands become sweaty during a round, for example. A golfer's clubs can be exposed to wet or moist conditions during use, even when in a golfer's bag during a round as various clubs are interchanged, as well as when placed in storage.
A few designs for covering golf club grips have been devised over the past few decades to help keep the grips dry. However, there exists a need for a cover that is adaptable to the grips of golf clubs or shafts on other sports equipment generally used by respective players of those sports today, that maintains engagement with such grips even while the golf club or other equipment is in use, and that allows the user to quickly cover and uncover the grips during use thereof.


A silver-colored pigment is provided having a nonmetallic platelet-shaped substrate and at least one ilmenite-containing coating, wherein the nonmetallic platelet-shaped substrate is a nonmetallic platelet-shaped synthetic substrate and the amount of iron compounds, calculated as elemental iron, in the pigment is less than 5.0 % by weight, based on the total weight of the pigment. Processes for preparing the pigment also are provided.

1. Field of the Invention
The present invention relates to silver-colored pigments comprising nonmetallic platelet-shaped synthetic substrates and at least one ilmenite-containing coating with an amount of iron compounds, calculated as elemental iron, in the pigment of less than 5% by weight, based on the total weight of the pigment, a process for the preparation thereof as well as the use thereof. The invention further relates to an object which is provided with the silver-colored pigments according to the invention as well as a preparation which comprises the latter.
2. Description of Related Art
WO 2004/099319 A2 describes interference pigments with a high covering power, high luster and color change at varying viewing angles, comprising a platelet-shaped substrate and at least one FeTiO3-containing layer. The proportion of FeTiO3 in the layer is 8 to 100% by weight, based on the total weight of the layer. These interference pigments are prepared by the simultaneous deposition of titanium(IV) oxide hydrate and iron(III) oxide hydrate on the substrate surface and subsequent thermal treatment under reducing conditions. A homogeneous distribution of ilmenite inside the coating is thus to be guaranteed.
WO 97/43348 A1 describes unsupported single or multi-coat pearlescent pigments consisting of iron titanate and possibly titanium oxide and/or iron oxide. To prepare these pearlescent pigments, titanium dioxide platelets obtained via a belt process are coated, without intermediate drying, with iron oxide in a wet process, and the resulting pigments are dried and calcined in an oxidizing or reducing gas atmosphere. The pearlescent pigments obtained have a high color strength and exhibit for example a color flop from red to gold or from gold to red. It is also possible to obtain blue-black lustrous pigments.
EP 0 246 523 A2 relates to colored pearlescent pigments, which are for example black-gold, black-red, black-green or dark blue, based on a platelet-shaped substrate which is provided with a compact coating containing iron(II) oxide. The layer containing iron(II) oxide can have a different composition here depending on the preparation process and the substrate used. This invention is aimed at pigments with a high conductivity, which manifests itself in a good shielding from electromagnetic interference fields.
Furthermore, these pigments can be easily aligned in magnetic fields because of their magnetizability.
Commercial ilmenite-coated pearlescent pigments based on natural mica are characterized by R. Maisch in the article, New effect pigments from grey to black, Progress in Organic Coatings, 22 (1993) 261-272.
The use of ilmenite-containing interference pigments, which can be black for example and exhibit strong interference colors at the specular angle, to produce forgeryproof documents and packaging is known from EP 0 681 009 B1.
Many everyday fields can no longer be imagined without silver hues, silver vehicles lend distinction to the streetscape and a silver coloring or varnish gives everyday objects like coffee machines, television sets or packaging a high-class appearance. Metallic effect pigments, in particular aluminum effect pigments, critically determine the silver hue. Regulatory limitations, such as e.g. in the color cosmetics sector, can however limit the field of use of metallic effect pigments. If electromagnetic shielding has a role to play, such as for example in the case of cellular phones, metallic effect pigments are often dispensed with in the varnish, although e.g. aluminum effect pigments, contrary to widespread opinion, are not electrically conductive. If the metallic effect and the visual impression of an aluminum effect pigment are to be preserved in an application, a simple substitution by a silver-colored pearlescent pigment is not possible. Commercial silver-colored pearlescent pigments for example generally do not possess the neutral silver hue that is characteristic of aluminum effect pigments. There is a need, therefore, for pigments that in terms of the optical properties such as, for example, silver hue, opacity, metallic gloss or light/dark flop, come close to metallic effect pigments, yet contain no metal and can thus contribute to the field of use of metallic effect pigments.
The problem on which the present invention was based was that of providing highly lustrous silver-colored pigments which in terms of their visual impression have properties that are characteristic of metallic effect pigments. The silver-colored pigments are not to differ, or to differ only insignificantly, from commercial aluminum effect pigments in their appearance. At the same time, the silver-colored pigments are to be characterized by a high chemicals stability and temperature resistance. The problem on which the invention is based is further that of providing a process for preparing these silver-colored pigments.

This patent is subject to a terminal disclaimer.

Highly lustrous silver-colored pigments with high opacity and metallic appearance, process for the preparation thereof and use of same


The invention relates to a method for producing an ice projectile. The method comprises the steps of: —providing a quantity of water; providing a quantity of alcohol corresponding to at least 5 wt.-% of the quantity of water; mixing the quantity of water with the quantity of alcohol; transferring the mixture to means for cooling and solidifying the mixture to form a piece of ice; cooling the mixture in the cooling and solidifying means to a mixture-solidification temperature in order to produce at least one piece of ice; and launching the or each piece of ice at a target using launching means.

In the field of aeronautics, it is necessary to test the resistance of some structures to hailstones. This is for example the case of aircraft windscreens or jet engine blades.
Currently, there are four major methods used to make a projectile simulating a hailstone.
A first method allows making a hailstone close to what nature makes. According to this method, the projectile is made by successive solidifications of supercooled suspended water droplets. Another known method is the manufacture of a hailstone by continuous solidification of water vapor around a cold finger. These two methods allow obtaining mechanical properties close to those of the natural hailstone, but are very long and complex to implement.
Another method consists in placing water, where possible distilled or demineralized water, in a freezer type cooling enclosure. The mold in which the water is placed confers a first preform of the final shape, and a machining or a final polishing perfects the shape. This ice projectile, homogeneous in its composition, has significantly more degraded mechanical properties (worse mechanical strength) than those of the natural hailstone.
Finally, it is known to add a cotton ball, or more generally fibers, to water, where possible distilled or demineralized. This method is the subject of a standard «ASTM F320: Standard Test Method for Hail Impact Resistance of Aerospace Transparent Enclosures». As for the aforementioned ice projectile made of only water, the whole is placed in a cooling enclosure and the shape is given by the mold, then a mechanical or manual finish is carried out. This ice projectile, heterogeneous in its composition, has significantly better mechanical properties (better mechanical strength) than those of the natural hailstone.
The drawback of the first two techniques is the complexity and the very long duration of manufacture of the ice projectile. The drawback of the third technique is the use of a projectile which is less resistant than the natural hailstone, and therefore the making of a less destructive test than with a real hailstone and consequently, the underestimate of the impact of a real hailstone. Conversely, the drawback of the fourth one is to lead to a test which overestimates the impact of a real hailstone. In addition, this fourth technique, by the heterogeneous nature of the projectile, can induce a considerable dispersion between two tests for small-sized projectiles. Generally, in order to supervise the actual effects of hail, the third and fourth techniques are used together, which amounts to doubling the number of tests.

Method for manufacturing an ice projectile

COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES


A tire pressure monitoring system (12) for an automotive vehicle (10) has a receiver circuit (28). The vehicle (12) has a plurality of wheels (14A-14D). A plurality of antennas (31A-31D) are adjacent to one of the wheels (14A-14D). The plurality of antennas receive RF signals from a pressure sensor (16A). An adder circuit (30) is coupled to the receiver circuit and the plurality of antennas. The adder circuit receives the RF signals and adds them together to form a sum signal. The sum signal is coupled to the receiver circuit.

The National Highway Traffic Safety Administration is requiring a phase in of tire pressure monitoring systems in vehicles. Various types of pressure sensing systems for monitoring the pressure within the tires of an automotive vehicle have been proposed. Such systems generate a pressure signal using an electromagnetic (EM) signal which is transmitted to a receiver. The pressure signal corresponds to the pressure within the tire. When the tire pressure drops below a predetermined pressure, an indicator is used to signal the vehicle operator of the low pressure. Many vehicles require different tire pressures in the front of the vehicle and the rear of the vehicle. Therefore, it is important to know the relative position of the pressure sensor and thus the tires relative to the vehicle.
Proposed tire pressure monitoring systems use RF signals between a receiver and the pressure sensors. RF reception between the tire pressure monitoring sensors in each wheel and the tire pressure monitoring receiver is not always sufficient. RF reception between the tire pressure monitoring sensors and the receiver is not fully predictable during the design process of the vehicle. Robust designs require extensive in-vehicle testing of representative vehicles to establish the receiver location within or outside of the vehicle. Various impediments to the RF signals include the sheet metal, wiring variations, powertrain, and wheel configurations. Such designs are typically not available until late in the product development cycle. Using a conventional receiver located within or outside the vehicle and the various pressure monitoring systems may therefore be inhibited.
It would therefore be desirable to provide a system that prevents attenuation of the RF pressure sensor signal so that reliable pressure monitoring may be performed.

Method and apparatus for receiving signals from a sensor into a tire pressure monitoring system


A simple, compact, hands free device that allows a single operator to vertically lift and hold construction panels to a desired height for securing to a wall surface. Downward foot pressure on one end of a slotted lever arm causes a panel lifting surface on the other end of the lever arm to rise. This lever arm is supported by a base support which also supports a locking arm. Once the desired height is reached, the device locks the panel into position. The operator is then free to move about, adjust, and finally secure the panel. Once the panel is secured, the locking arm is released by simple forward pressure. With the aid of a foot strap, the device can then be transported to the next panel ready for lifting. This device eliminates the use of hands, bending, or stooping during the process of lifting construction panels.

Not applicable
This invention was not conceived or produced with the aid of any federally sponsored research or development.
1. Field of Invention
This invention relates to a panel lifting device, specifically a simple, inexpensive, hands free device designed to vertically lift and hold construction panels in place for adjusting and securing.
2. Description of Prior Art
Originally devices used for lifting construction panels have included such things as a simple block and pry bar or automobile leaf spring that the installer must stand on. The disadvantage of these devices is that they do not hold a panel in place for securing. Also, the operator must pry and hold with hand or foot at the same time they are adjusting and finally securing the panel. This can cause injury to the operator due to imprecise nature of the devices and imprecision of placement of the panel.
A door transporting and mounting machine in U.S. Pat. No. 4,820,151 to Shern, Mar. 7, 1989 will lift and place a panel against a wall but will not allow for placing the panel laterally flush against an adjacent panel. One disadvantage is that the panel must first be lifted into the device. It also lacks simplicity, low cost of construction and purchase, relative ease of operation, and hands free operation.
A ceiling panel lifting device in U.S. Pat. No. 3,828,942 to Young, Aug. 13, 1974 can be used to lift and hold panels in a vertical position but lacks simplicity, low cost of construction and purchase, relative ease of operation, and hands free operation. Also, the panel itself must initially be hoisted into the device prior to lifting.
Other devices including but not limited to:
(a) U.S. Pat. No. 5,732,527 to Schneider, Mar. 31, 1998
(b) U.S. Pat. No. 4,027,802 to Reynolds, Jun. 7, 1977
(c) U.S. Pat. No. 2,969,220 to Spencer, Jan. 24, 1961
all function only to lift and hold panels against a horizontal ceiling and are not suitable for use in vertically lifting and holding a panel against a vertical wall.
In accordance with the present invention, a compact panel lifter vertically lifts and holds building panels from bottom edge of panel on floor position to bottom edge of panel at a desired height relative to the floor comprising a lever arm, tab, lifting surface, and locking mechanism supported by a self contained support body allowing for hands free foot operated lifting and locking in position of construction panels as well as hands free foot operated lock release of the device with automatic return of the device to the ready position and foot facilitated hands free transfer of the device to subsequent panels.
Accordingly, besides the objects and advantages of a compact panel lift device described in my above patent, several objects and advantages of the present invention are:
1. Simple, hands free operation promoting hand safety.
2. Low cost of construction and purchase.
3. Ergonomic transfer of the unit to subsequent panels thus eliminating stooping, bending or squatting with resultant promotion of healthy back hygiene.
4. Locking of the unit into the lifted installation position for adjusting and securing of a panel.
5. No arc of travel when raising a panel thus reducing the risk of the panel falling off a lift structure or the panel pulling away from the wall.


A system includes a database with a plurality of records, each record including a plurality of data fields. The system receives input from an end user. The end user input is received via an end user interface, and the end user input includes a subset of the plurality of data fields. The system queries the database using the subset of data fields, and data is retrieved from the database using the subset of data fields. The data retrieved from the database substantially include only data fields that are the data fields supplied by the end user. In an embodiment, the retrieved data do not include data fields that are not part of the data fields supplied by the end user.

Traditional end user database reporting methods read a great deal of detailed information and then display only a portion of that detailed information (i.e., the fields in the report output and not all the data read from the database) at a high level of detail (i.e., a great deal of data records without aggregation). This is the case even though oftentimes an end user is interested in an aggregated view (e.g., totals grouped by specific dimensions). This traditional approach consumes a lot of resources. For example, many irrelevant details are read from the database, a vast amount of resources is allocated for many rows and many columns, and there are long response times. That is, a good amount of time is spent in the database reading irrelevant information, which is not displayed. And even if only the fields to be displayed are read from the database, oftentimes the structure used for working with the information read from the database is made up of all the data fields of a record, the reading of which results in an unnecessary allocation of memory.

Layout-driven data selection and reporting


Pixels on the edge (A, B, C, D; E, F, G, H; I) of previously predicted neighboring picture blocks (A′, B′) are used for directional prediction of a picture block (C′). Depending on the prediction direction, the pixels used for prediction are prefiltered along an edge of the actual picture block to be predicted (C′) in order to suppress prediction artifacts.

The present invention is directed to a method for directional prediction of a picture block composed of pixels, in particular for the intra prediction of picture blocks greater than 4×4 pixels in size.
It is made known in reference [1], http://standard.pictel.com/ftp/video-site/0109 San/, in particular on pages 9 through 11, that video coding standard H.26L entails carrying out intra prediction on 4×4 pixel blocks or 16×16 pixel blocks. "Intra prediction" means that only that information about an actual picture that was previously transmitted is used to generate a prediction signal (e.g., the first picture in a video sequence is always "intra" coded). According to [1], six modes are available for 4×4 prediction. These modes differ in terms of the direction from which prediction takes place. In this process, the pixels on the edge of previously predicted (coded) neighboring picture blocks are used for prediction.

Method for conducting a directed prediction of an image block


A single track vehicle having a foot pedal lever activated side wheel extension/retraction mechanism is fitted with a hydraulic system for responding to excessive feedback force imparted to the driver's leg via the foot pedal. The system includes a normally open needle valve installed mechanically in line with a linear actuator to sense the magnitude of the feedback force to the driver's feet. If the feedback force exceeds the amount the driver can counter comfortably, the needle valve is closed as a result of the opposing force vectors between the loaded side wheel and the driver's feet. The system further includes an inertially activated hydraulic valve installed on the vehicle frame. In the event of a head-on crash, the valve closes, freezing a gas strut and thereby holding the foot pedal lever in the aft position, preventing injury to the driver.

The subject invention relates to single track vehicles and, more particularly, to apparatus for limiting the amount of feedback force which can be exerted on the driver by a foot pedal extension/retraction system and for responding to vehicle deceleration to halt forward movement of the foot pedal which might injure the driver.
An improved single track vehicle is taught in my U.S. Pat. Nos. 5,257,671 and 5,628,379. During five years of development work on improvements in single track vehicle design, a number of problems have persisted related to control of the extendable/retractable side wheel system. Such a system may employ a foot pedal lever controlled side wheel extension mechanism, as well as a side wheel retraction mechanism employing a spring or a spring like mechanism, such as a gas strut. In the side wheel retraction mode, the gas strut pushes the foot pedal aft as the gas strut extends. To extend the side wheels, the foot pedal lever is driven forward with the feet pressing against the foot rests of the foot pedal lever, overcoming the force exerted by the gas strut.
One of the problems with such prior systems occurs when the side wheels transfer a force to the driver's feet which is so great that the driver cannot counteract it with his legs. This situation typically occurs when the vehicle is improperly driven in the held-up by side wheel mode, such as turning a corner with the vehicle leaning to the outside of the corner rather than the inside of the corner. Even with the best driver, when starting out on a sloped roadbed and turning in the up-slope direction, such tuning may be unavoidable.
Another problem occurs in the event of a sudden stop of the vehicle, as may be experienced in a head-on crash. In such case, inertia may cause the foot pedal lever to be driven forward and into the driver's legs causing serious injury. My prior designs addressed this problem by use of a hook or latch mechanism to hold the foot pedal lever, and hence the side wheels, in the retracted position. Such a latch mechanism is shown in FIG. 29 and requires driver activation of the foot pedal lever to release the lever from its latched position. This latch mechanism has the disadvantage that it only works if the foot pedal lever is in the fill aft position. In addition, the operation of the mechanical system is not seamless and requires more leg travel to activate, which detracts from the available leg travel for lowering the side wheels.

Single-track vehicle with foot pedal feedback and inertial force limiters


The apparatus includes two permeators mounted in series, namely a simple permeator with an inlet and two outlets, and a reflux permeator. The production gas results from the combination of the two permeated products. Application to the production of impure hydrogen.

(a) Field of the Invention
The present invention relates to a process and an apparatus for the production of an impure light gas by permeation, starting from a gaseous mixture. It is particularly applicable to the production of impure hydrogen starting from a mixture consisting essentially of hydrogen, nitrogen and hydrocarbons.
(b) Description of Prior Art
In some industrial applications, hydrogen is needed, which has a low purity, lower than that which may be obtained with simple permeators, i.e. having an inlet and two active outlets, namely a high pressure inlet, a high pressure outlet and a low pressure outlet.
To increase the hydrogen extraction yield while lowering its purity, it has been proposed to bypass a portion of the supply flow or "feed". It has also been proposed, for the same purpose, to use reflux permeators, instead of simple permeators, in which a portion of the residual gas is returned in the low pressure space in order to lower the partial pressure of hydrogen therein. These expedients enable to effectively increase the yield of extraction of hydrogen or, for a given yield, to decrease the investment, i.e. essentially the required surface of the permeation membrane.
The invention aims at increasing much more importantly the increase of extraction yield or of the investment.

L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude


The present invention relates generally to production methods, enzymes and recombinant yeast strains for the biosynthesis of clinically important prenylated polyketides of the cannabinoid family. Using readily available starting materials, heterologous enzymes are used to direct cannabinoid biosynthesis in yeast.

Cannabis sativa varieties have been cultivated and utilized extensively throughout the world for a number of applications. Stems, branches, and leaves are used in fibers and fiber-based products; sprouts and seeds as food; seeds for inexpensive oils; flowers for aromatic, recreational, ritual and medicinal purposes; and flowers and roots for nutritional and additional medicinal and pharmaceutical applications. Indeed, many controlled clinical studies and anecdotal or open-label studies in humans have been documented that demonstrate beneficial effects of both plant extracts and purified C. sativa plant compounds in many human medical conditions. Beneficial activities of the cannabinoid family of compounds described from human studies range from neurological to mood/behavior disorders, and to gastrointestinal disorders as well as sleeping, appetite and fatigue problems. Other uses or potential uses include the treatment of various microbial and viral infections and the treatment of a number of cancers. Thus, as a direct result of this burgeoning list of human therapeutic indications, there currently exists an unfulfilled need for the production of pharmaceutical grade cannabinoids using sustainable, modern biopharmaceutical preparation methods.
Currently, the cannabinoids are isolated primarily via the cultivation of large acreages of cannabis or hemp plants in agricultural operations throughout the world, with a lower, albeit clinically important level of production methodologies that involve synthetic chemical processes. The former techniques are costly, utilize large quantities of natural resources, such as arable land and water and invariably lead to final pharmaceutical products that contain additional active cannabinoids that contaminate the desired active drug substances. This can lead to an inconsistency in the activities of the desired pure compounds leading to spurious activities in both clinical trial situations and in marketed products. Furthermore, the contamination of natural plant-derived cannabinoid preparations by toxic metals and pesticides is a problem that currently is in need of a solution. Also, because of the complex stereochemistry of many of the cannabinoids, chemical synthesis is a difficult, expensive and low-yielding process. Furthermore, the synthetic chemical production of a number of cannabinoids has been reported to produce less pharmacologically active molecules than those extracted from the C. sativa plant.
Synthetic biology, however, whereby products of interest are biosynthesized using isolated genetic pathways in engineered microorganisms, offers potential solutions to the large-scale commercial manufacture issues of many naturally occurring compounds.
The first chemical building blocks of the cannabinoid molecules and their analogs are polyketides that are derived in nature from a type III polyketide synthase (PKS). For a detailed description of PKSs in C. sativa, see Flores Sanchez, I. J., 2008, Doctoral thesis, Leiden University and Sanchez and Verpoorte, Phytochem Rev (2008) 7:615-639.
Polyketides generally are synthesized by condensation of two-carbon units in a manner analogous to fatty acid synthesis. In general, the synthesis involves a starter unit and extender units; these starter units are derived from, for example, acylthioesters, typically acetyl-, coumaroyl-, propionyl-, malonyl- or methylmalonyl-coenzyme-A (CoA) thioesters. The first enzymatic step in the biosynthesis of the more prevalent cannabinoids, however, is the formation of olivetolic acid by a type III PKS enzyme that catalyzes the condensation of hexanoyl-CoA with three molecules of malonyl-CoA to form a tetraketide that is then cyclized and aromatized by a separate gene-encoded cyclase enzyme. The major cannabinoids, including 49-tetrahydrocannabinolic acid and cannabidiolic acid, are thus formed from the initiating precursor hexanoyl-CoA, a medium chain fatty acyl-CoA. Other, less prevalent cannabinoids with variant side-chains are formed from aliphatic-CoAs of different lengths (e.g., Δ9-tetrahydrocannabivarinic acid is formed from an n-butanoyl-CoA starter unit). Several additional and related analogs are found in nature, and others have been chemically synthesized.
Type I and many type III iterative PKSs are enzymes with sites that are used repeatedly to reach the final polyketide product, with certain type III PKSs, including OA synthase, also requiring the action of a cyclase enzyme to catalyze effecting the final steps, namely cyclization, dehydration and aromatization of the linear tetraketide precursor.
The next steps in the natural biosynthetic pathway to the major cannabinoids involve prenylation of olivetolic acid or an olivetolic acid analog (e.g., a 2-alkyl-4,6-dihydroxybenzoic acid), wherein a 10-carbon geranyl-diphosphate is condensed by the prenylase geranyl-diphosphate:olivetolate geranyl transferase (GOT) (Fellermeier and Zenk, 1998) to yield cannabigerolic acid (CBGA); which is further oxido-cyclized, for example, into CBDA, 49-THCA and CBCA (Morimoto et al., 1999) by the enzymes cannabidiolic acid synthase (Taura et al., 2007), Δ9-tetrahydrocannabinolic acid synthase (Sirikantaramas et al., 2004) and cannabichromenic acid synthase (Morimoto et al., 1998), respectively.

Recombinant production systems for prenylated polyketides of the cannabinoid family


The invention relates to an apparatus for generating a plurality of charged particle beamlets, comprising a charged particle source for generating a diverging charged particle beam, a converging means for refracting said diverging charged particle beam and a lens array comprising a plurality of lenses, wherein said lens array is located between said charged particle source and said converging means.

The present invention relates to an apparatus for generating a plurality of charged particle beamlets. Charged particle beams are used in a variety of systems, like lithography and microscopy systems. Some of these systems use a single source generating one beam which is subsequently split into a plurality of beamlets. The charged particle source used in these systems emits a charged particle beam with a defined opening angle, i.e. a diverging beam. The diverging beam often needs to be collimated, i.e. transformed into a parallel beam. In most applications a lens or lens assembly is used to refract the diverging beam emitted.
However, the change of angle of a charged particle beamlet is not exactly defined due to so-called chromatic aberrations. As a result the spot size of the beamlets on the target to be exposed or imaged also increases.
In GB2340991 and in U.S. Pat. No. 5,834,783, U.S. Pat. No. 5,905,267, U.S. Pat. No. 5,981,954, U.S. Pat. No. 6,124,599, U.S. Pat. No. 6,137,113, U.S. Pat. No. 6,166,387, U.S. Pat. No. 6,274,877, and the Journal of Vacuum Science and Technology B18 (6) pp. 3061-3066, charged particle beam lithography systems are disclosed, comprising a lens assembly for refraction of a diverging beam into a parallel beam. After refraction, the beam is split up into a plurality of beamlets using an aperture array. In these lithography systems an image of the apertures is projected on the surface to be exposed. To decrease the spot size, the image is reduced by a factor 200. The aberrations are dominated by the aberrations of the last lens in the system and not by the aberrations of the collimation assembly. However, these aberrations will affect the performance of the system.
The lens assembly in such systems has a chromatic aberration Δβ=C•ΔE/E•β, wherein β is the angle of an incoming ray with respect to the normal of the lens assembly and E the energy of the incoming charged particles. If Δβ is comparable to the intrinsic angle in the beam, it contributes to the size of the spots, which are formed on an object, e.g. a wafer with resist, to be processed.

Apparatus for generating a plurality of beamlets

Abstract: In this way, it is possible to reduce aberrations of the converging means.


A method for estimating an atmospheric condition existing between a portion of the Earth's surface and an airborne mobile platform travelling over the portion of the Earth's surface. The method may involve emitting a radar signal beam toward the Earth's surface from the mobile platform and receiving back at least a portion of the radar signal beam reflected from the Earth's surface. The time of flight information of the radar signal beam is analyzed as a function of elevation angle to determine a specific time of flight value associated with a specific elevation angle of the radar signal beam. The specific time of flight value is used to determine a refractivity of the atmosphere through which the radar signal beam and the reflected radar signal has passed. The refractivity is used to determine the atmospheric condition.

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Various systems have been used over the years to help measure atmospheric conditions with the goal of predicting weather conditions. One such method is the use of radiosondes, also known as weather balloons. These devices measure temperature humidity and other variables from the ground up to fairly high altitude. Another approach has been to drop parachute the equivalent of radiosondes from in-flight aircraft. Still another approach has involved Global Positioning System (GPS) occultation measurements from low orbiting satellites, such as the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) constellation of six satellites. Yet another approach has been to use GPS or IRIDIUM (c) occultation measurements taken from in-flight aircraft. IRIDIUM refers to the Iridium Satellite LLC of Bethesda Md.
The above approaches have met with varying degrees of success. For example, radiosonde measurements are effective but their use is limited to industrialized countries over land. The infrastructure to routinely launch and monitor them is lacking in many nations, and particularly over seas and oceans, which cover a substantial portion of the Earth's surface. Dropping small parachute packages from airborne aircraft is technically effective, but is costly over time and in some situations may raise environmental issues.
GPS occultation with satellites makes effective measurements only at fairly high altitudes. The GPS signal is typically too week to effectively traverse the lower atmosphere with sufficient signal quality to allow an occultation measurement. In addition, the spatial and temporal coverage of low Earth orbit (LEO) satellite constellations is too sparse to allow comprehensive coverage.
GPS or Iridium occultation measurements from aircraft provide better coverage than measurements from satellites. Measurements also reach somewhat lower altitudes because the signal does not need to traverse the entire atmosphere twice. However, there is the cost of installing additional antennas and occultation receivers on the aircraft, which in some cases may add significantly to the cost of implementing such a system. Reflected signal occultation is technically better than standard occultation. The reflected signal, especially using Iridium satellites, reaches all the way to the surface, allowing a full profile of the atmosphere to be measured. However, as with standard occultation, this method requires adding special antennas and receivers to the aircraft, and therefore may increase the cost of implementing such a system.

System and method using airborne radar occultation for measuring atmospheric properties


An abrading tool includes a base member having a support portion defining a first level, and a plurality of integral raised islands extending upwardly above the first level. The base member may be formed of metal or a non-conductive material. The islands are spaced apart from one another. Each island includes a respective tip portion. The distance between adjacent islands may be greater than the width of a single island. An abrasive composite material, including a carrier material and particles of an abrasive material, is affixed to the tip portions of at least some of the islands. The abrasive material may be applied by electroplating, electro-less plating, brazing or another method. The abrasive material is applied only to the tip portion of the islands, such that the first level of the support portion is substantially free of the abrasive material. Methods of making the abrading tool are also described.

1. Field of the Invention
The present invention relates to abrading tools and to methods of making such abrading tools. More particularly, the present invention relates to an abrading tool including a base member including a main sheet having a plurality of raised islands thereon, the islands being spaced apart from one another and having a composite abrasive material attached to respective tip portions thereof, and also to a method of making such a tool. The main sheet may be flat, or alternatively, the main sheet may be configured in a three-dimensional shape.
2. Description of the Background Art
A number of different tools and materials are known for use in abrading wood, metals, plastics, concrete, and other materials. Many hand tools as well as power tools are available for use in grinding, sanding or filing.
However, a problem exists with some of the known tools in that where a large, substantially continuous abrading area of the tool surface contacts the workpiece being treated, friction between the tool and the workpiece may create some resistance therebetween, and may also generate heat. Also, finely divided particulate or powdered waste material (referred to herein as swarf), which has been removed from the workpiece during abrading, may have a tendency to accumulate and to clog up the working surface of a conventional tool, such as sandpaper or the like.
Some efforts have been made to provide tool surfaces having open pathways provided on grinding or sanding surfaces thereof, to permit swarf to flow away from such surfaces.
Although the known abrading tools have some utility for their intended purposes, a need still exists in the art for improved, durable and cost-effective abrading tools and materials.
Accordingly, it is an object of the present invention to provide improved abrading tools, and methods of making such abrading tools.

Abrading tools and methods of making same


A display apparatus includes a display and a display filter, wherein the display filter includes a base film, a plurality of reflective elements, and a plurality of light absorbing elements, wherein each of the light absorbing elements corresponds to a reflective element.

1. Field of the Invention
Embodiments of the present invention relate to a filter and a display apparatus having the filter. More particularly, embodiments of the present invention relate to a filter that may increase bright room contrast by increasing transmittance of light emitted from inside the display apparatus and blocking light incident from outside the display apparatus, and a display apparatus having the filter.
2. Description of the Related Art
A display apparatus may include a filter in order to effect changes in various display characteristics, such as reducing reflections, etc., and to protect the display against damage. However, such a display apparatus may exhibit double reflections due to refraction caused by a material difference between a front of the display and the filter. Also, a tempered glass filter may be used to protect the display apparatus, but such a filter may need to have a thickness of 3 mm or more to resist external impact, which increases the weight and cost of the display apparatus. Furthermore, a tempered glass filter may have a complicated structure including various filters having various functions. Therefore, the process of manufacturing the tempered glass filter may be complicated and costly.

Filter and display apparatus having the same


An optoelectronic device includes a silicon substrate, with a silicon waveguide layer disposed over the silicon substrate and including an optical waveguide. One or more through-silicon vias (TSVs) extend through the silicon substrate and contact the silicon waveguide layer. A III-V base layer is disposed over the silicon waveguide layer, and an optical amplifier is disposed on the III-V base layer and optically coupled to the optical waveguide.

Photonic integrated circuits (PICs) integrate multiple optical and optoelectronic functions in a single device, fabricated on a semiconductor substrate. These functions include both passive routing elements, such as waveguides, splitters, couplers and resonators; and active elements, such as tuners, modulators and detectors, as well as lasers. Some PICs incorporating lasers that are currently known in the art are fully implemented on a III-V substrate, resulting in low-yield and high cost. Other PICs are made on silicon substrates using CMOS-compatible processes and are then integrated with a separately-fabricated laser (III-V) and other components, usually on an optical interposer. This latter approach allows utilization of the large-scale production, low cost and high yield that Si-photonics inherit from CMOS processing, but suffers from difficult, costly assembly based on "pick and place" tools.
Recently, a number of foundries have developed the capability of integrating III-V laser dies on SOI (silicon on insulator) wafers, together with silicon-based waveguides and other optical and electro-optical components. One of the techniques that has been developed for this purpose is hybrid integration, in which an unprocessed III-V wafer is bonded to a silicon wafer that has been patterned with optical waveguides. Multiple III-V hybrid lasers are then fabricated simultaneously across the wafer by epitaxial deposition on the III-V wafer and standard fabrication techniques. Because the silicon waveguides are patterned before laser fabrication, the lasers are precisely aligned with the waveguides, without requiring fine alignment between the unpatterned III-V wafer and the patterned silicon wafer.

High-power hybrid silicon-photonics laser


An epidural or anesthesia needle assembly having a "wing" selectively attachable to the needle hub is disclosed. The "wing" is made of a sturdy but resilient material. The "wing" has a tang for placing in a corresponding slot in the needle hub to ensure the correct orientation of the "wing" with the bevel tip of the cannula. In addition, the tang allows the "wing" to be pushed along the elongated axis of the cannula with improved efficiency so that the "wing" does not become inadvertently detached from the needle hub. In the preferred embodiment, the "wing" includes a protective sheath mount enclosure shaped in contour to the protective sheath mount located at the most distal end of the needle hub. The protective sheath mount enclosure forms a lock around the protective sheath mount. The contour shape of the protective sheath mount enclosure encloses the protective sheath mount so that as the "wing" is moved either proximally or distally, the resilient material of the "wing" around the protective sheath mount enclosure moves into locking contact with the protective sheath mount.

1. Field of the Invention
This invention relates to needle assemblies and more specifically to assemblies, such as epidural and anesthesia needle assemblies, that require finger sensitivity and finger control in placement of the cannula in a patient's body.
2. Description of Related Art
Many needle assemblies are known for placing cannulae in the body. In some cases, an incision is cut into the body and a cannula placed therethrough. In others, a cannula is inserted directly into the body. Thereafter, a catheter is placed through the cannula into the body. In many cases it is desirable to use finger control to insert and position the cannula in the body. Often it is desirable to have a great amount of finger sensitivity when placing the cannula in the body to precisely position the cannula. In addition, it is often desirable to have means to readily move the cannula into and out of the body along the elongated axis of the needle assembly.
To satisfy these requirements, needle assemblies having finger manipulation members or "wings" that extend away from the elongated axis of the needle assembly at approximately right angles have been developed. In one method of use, these "wings" allow the physician to grasp the needle assembly with two fingers on the "wing" while placing the thumb on the proximal or non-patient contacting end of the needle assembly. The needle assembly is held by the proximal force put on the wing by the physician's fingers counter balanced by the distal force put on the proximal end of the needle assembly. In this way, distal directed pressure can be applied to the needle assembly by the thumb to push the cannula into the body or the cannula may be moved proximally out of the patient's body by the proximal movement of fingers pulling on the "wings". In addition, the "wings" allow the physician to turn the needle assembly around its elongated axis by rotating his wrist in order to more precisely position the cannula and its typically beveled distal end.
In another method of use, the physician grasps the "wings" with both hands by holding each "wing" between the corresponding thumb and index finger of each hand. In this method, one hand holds the "wing" extending from one side of the needle assembly while the other hand holds the "wing" extending from the other side of the needle assembly. The physician may then either push or pull on the "wings" thereby moving the cannula into or out of the patient's body, respectively. In this method of use, the physician may turn the needle assembly, and consequently the cannula, around its elongated axis by raising or lowering one "wing" relative to the other.
A standard epidural needle assembly is shown in FIG. 1 generally labeled 2. The needle assembly 2 includes a cannula assembly 4 comprising an elongated hollow cannula 6 attached to a needle hub 8. The patient contacting or distal end 10 of cannula 6 typically has a bevel to produce a sharpened end. The needle hub 8, located at proximal end 12 of cannula assembly 4, is finger manipulated by the physician so that cannula 6 may be inserted into the patient's body. A bore 14 extends through needle hub 8 from the proximal end 12 of cannula assembly 4 to the inner bore of cannula 6. A slot 46 extends into needle hub 8 from its proximal end 12. Slot 46 is located along the outer surface of needle hub 8 parallel to bore 14.
Needle assembly 2 also includes a stylet assembly 16. Stylet assembly 16 includes a stylet 18 and a stylet hub 24. Stylet 18 is typically a solid metal rod. The distal end 20 of stylet 18 generally has a bevel corresponding in angle to the angle of the bevel of the distal end 10 of cannula 6.
Stylet hub 24 is located at the proximal end 22 of stylet assembly 16. Stylet hub 24 includes a tang 26 directed toward the distal end 20 of stylet assembly 16. In operation, as will be explained hereafter, when stylet 18 is placed through bore 14 into cannula 6 so that the distal end 20 of stylet 18 is aligned with the distal end 10 of cannula 8, tang 26 will intermesh with slot 46 in needle hub 8 to precisely orient the beveled distal end 20 of stylet 18 with the beveled distal end 10 of cannula 6.
When stylet 18 is fully inserted into cannula 6 and the beveled distal end 20 of stylet 18 and the beveled distal end 10 of cannula 6 are aligned by tang 26 intermeshing with slot 46, a flat surface is presented across the beveled distal ends 10,20 of cannula 6 and stylet 18, respectively. This provides a substantially closed surface at the distal end 10 of cannula 6 to prevent coring of the patient while inserting the cannula 6 into the patient.
Stylet hub 24 also includes a thumb piece 28 located on the proximal end 22 of stylet assembly 16. Thumb piece 28 allows the physician to move stylet assembly 16 distally by pushing on thumb piece 28 with the physician's thumb.
A protective sheath 30, typically comprising a rigid cylindrical plastic tube, is provided to encase cannula 6 when not in use and prevent inadvertent contact with the sharp beveled distal end 10. Protective sheath 30 has a proximal end 32 that contacts a protective sheath mount 36 located at the distal end of needle hub 8. When protective sheath 30 is in position over cannula 6 so that the proximal end 32 is in contact with protective sheath mount 36, protective sheath 30 is sufficiently long so that the distal end 34 of protective sheath 30 extends beyond the distal end 10 of cannula 6. In this way, persons and objects are protected from unwanted contact with the sharp distal end 10 of cannula 6 by the covering of the rigid protective sheath 30. Protective sheath 30 is removed prior to the physician inserting cannula 6 into the patient's body.
Many epidural or anesthesia needle systems 2 have a wing 38 mounted on needle hub 8. Typically, wing 38 is a thin, substantially planar device that extends away from the main axis of needle hub 8 at substantially a right angle near the distal end of needle hub 8.
Many epidural or anesthesia needle assemblies 2 attach wings 38 to needle hub 8 permanently; in the case of metal needle assemblies 2, the wings 38 are soldered to the needle assembly 2. However, it is often desirable to be able to selectively remove wing 38. Therefore, wings 38 that may be removed from needle hub 8 are known.
One typical way to attach wing 38 to needle hub 8 is to form a slot in needle hub 8, substantially aligned with the plane of wing 38. A corresponding tab is formed on wing 38 to slide into and be constrained by the slot. However, a problem with this system for attaching wing 38 to needle hub 8 is that either proximal or distal pressure on wing 38 by the physician causes wing 38 to deform. As a result of wing 38 deforming, the tabs on wing 38 move out of constraining contact with the slot in needle hub 8, thereby detaching wing 38 from needle hub 8. Besides creating an annoying condition for the doctor, the condition is also potentially unsafe because the physician has temporarily lost control of the cannula 6 in the patient's body. Therefore it is highly desirable to provide an epidural or anesthesia needle assembly 2 with detachable wings 38 where the wings 38 may be securely fastened to the needle hub 8, yet easily removed if desired.
As stated, a problem with some prior art epidural needle assemblies 2 having wings 38 is that the wings 38 are integrally connected to the cannula. Consequently, in applications where it is desired that the epidural needle assemblies 2 be used without wings 38, a separate version of the epidural needle assembly 2 must be produced; one having and one not having wings 38. This leads to production duplication and inventory and storage problems. As a result, it is desirable to make an epidural needle assembly that may or may not be used with "wings" as desired.


A core bar for a rubber crawler includes: right and left wing parts; an engaging part for connecting the wing parts; right and left protrusions to guide a rolling wheel; and right and left outside rails that are formed on outer sides of the right and left protrusions, respectively, and have overhanging parts extending in the widthwise direction of the wing part. The overhanging part is formed on an edge portion thereof with a surface that slants downward from a top surface of the outside rail.

1. Field of the Invention
The present invention relates to a core bar for a rubber crawler and a rubber crawler used for a farm machine, a construction machine and the like and, to be more specific, to an outside rail type rubber crawler.
2. Description of the Related Art
In Japanese Examined Utility Model Publication No. HEI 7-17658, there is proposed a core bar for a rubber crawler having a pair of angular protruding parts (protrusions for preventing the coming-off of a rolling wheel) formed on both sides of an engaging part at the center between right and left wing parts, on outer side of each of the angular parts described above is formed a shoulder part (outside rail) elevated with respect to the wing parts of the core bar, wherein the respective shoulder parts are formed with overhanging parts that overhang in the front-rear direction (in the widthwise direction of the wing part), and wherein the top surfaces of the respective shoulder parts are slanted upward from the center to the end portions of the front and rear overhanging parts; and a crawler in which the core bars for a rubber crawler are embedded in a rubber crawler body with the top surfaces (rail surfaces) of the shoulder parts described above exposed on the inner circumferential surface of the rubber crawler so that the top surfaces of the shoulder parts form a rolling wheel track against which the outside collars of an outside collar type rolling wheel are abutted.
According to the related art described above, when the overhanging part is sunk, it is brought closer to an adjacent shoulder part (outside rail) in the circumferential direction (in the lengthwise direction) of the crawler to narrow the distance between the core bars, so that the rolling wheel track is made nearly continuous in the circumferential direction, thereby reducing vibrations as much as possible.
However, since the sinking of the overhanging part increases the height difference between the adjacent overhanging parts in the circumferential direction of the crawler and, when the rolling wheel is transferred to the next overhanging part, the rolling wheel collides with the next overhanging part causing noises and vibrations.
In particular, in a truck loader, a vibration roller, a bulldozer or the like, which mostly runs at comparatively high speeds, the collision of the rolling wheel with the overhanging parts tends to cause large noises and damages the overhanging part or the rolling wheel.

Core bar for rubber crawler and rubber crawler


The present application discloses a method and apparatus for making a low cost and highly efficient hollow waveguide for transmitting electromagnetic radiation. The waveguide is made from a solid substrate monolithic hollow tube with a reflectivity enhancing dielectric film formed directly over the inner surface. The film can be formed by native chemical reactions, with the material of the monolithic, hollow tube. The present application also discloses a method of polishing and cleaning the inner surface of the hollow tube.. One of the problems identified with the hollow metallic waveguide has been the poor surface finish on the inner wall of the hollow tube which results from the processes used to fabricate the metallic tube into final form. The coated reflectivity enhancing dielectric films more or less duplicate the surface roughness in the as formed tube thus seriously affecting the performance of the waveguide especially at the shorter wavelengths. The interior surface of the as received metal tubes can be significantly improved by chemically polishing and cleaning the tube and thereby improving the transmission characteristic of the wave guides for both infrared and visible wavelengths.

CO.sub.2 lasers are now being extensively used in medical, industrial and military applications, and a variety of optical fibers and hollow flexible waveguides have been proposed as the transmission medium for these applications. However, only hollow waveguides have proven to be economically and commercially possible for transmitting a relatively high flux of CO.sub.2 laser energy.
Although dielectric-coated hollow waveguides for transmitting electromagnetic waves have been studied since the 1950's, the fabrication method for dielectric coated hollow flexible waveguides at infrared CO.sub.2 laser wavelengths was not reported until 1983. (M. Miyagi, et al., entitled "Fabrication of Germanium-coated Nickel Hollow Waveguides for Infrared Transmission", Appl. Phys. Lett., Vol. 43, No. 5, Sep. 1, 1983.) Since then, various versions of that waveguide have been suggested and made by other groups.
Hollow waveguides are now used more often to transmit laser light in medical and industrial applications. In particular, the transmission of laser light at very different wavelengths (10.6 .mu.m and 0.6328 .mu.m) is ideally suited for hollow waveguides. Rigid hollow waveguides made of hollow alumina ceramic tubes encased in a stainless steel jacket have been used extensively to transmit a CO.sub.2 laser light in rigid endoscopic applications. (See U.S. Pat. No. 4,917,083, Apr. 17, 1990). These waveguides, however are limited in both length and power handling and can readily overheat or melt when the laser light is not properly launched into the waveguide. Also, ceramic tubes are not flexible due to their inherent lack of ductility, precluding their use in flexible waveguides.
Some types of known hollow metallic waveguides are not flexible enough and tend to overheat, limiting the maximum input power. Another plastic type of flexible hollow waveguide has a larger inside diameter and a lower power transmission efficiency.
The following U.S. Pat. Nos. disclose hollow waveguides and lightpipes for lasers: 4,652,083 to Laakmann on Mar. 24, 1987 for "Hollow Waveguide", 4,688,892 to Laakmann on Aug. 25, 1987 for "Hollow Waveguide Having Disparate Dielectric overcoating", 4,688,893 to Laakmann on Aug. 25, 1987 for "Hollow Waveguide Having Plural Layer Dielectric", 4,805,987 to Laakmann on Feb. 21, 1989 for "Hollow Waveguide Using A Low Refractive Index Inner Layer", 4,913,505 to Levy on Apr. 3, 1990, "Hollow Lightpipe and Method for Its Manufacture", 4,930 863 to Croitoriu et al. on Jun. 5, 1990 for "Hollow Fiber Waveguide And Method of Making Same", and 4,917,083 to Harrington et al. on Apr. 17, 1990 for "Delivery Arrangement for A Laser Medical System". These patents are hereby incorporated by reference.

Monolithic hollow waveguide and method and apparatus for making the same


Infrastructure equipment for transmitting data to and receiving data from a mobile device on a communications network is described. The infrastructure equipment comprising: transmitter circuitry configured to transmit the data to the mobile device; and controller circuitry configured to control the transmitter circuitry to transmit a first position reference signal in a first subframe and a second position reference signal in a second subframe, wherein the second position reference signal is a time adjusted version of the first position reference signal, the amount of time adjustment being determined by the sample time at which the mobile device samples the position reference signal.

The "background" description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art or may not form part of the state of the art at the time of filing, are neither expressly or impliedly admitted as prior art or state of the art against the present invention.
Mobile (or wireless) telecommunication systems, such as those based on the Third Generation Project Partnership (3GPP) defined Universal Mobile Telecommunication System (UMTS) and Long Term Evolution (LTE) architecture, are able to support more sophisticated services than simple voice and messaging services offered by previous generations of mobile telecommunication systems. For example, with the improved radio interface and enhanced data rates provided by LTE systems, a user is able to enjoy high data rate applications such as video streaming and video conferencing on mobile communications devices that would previously only have been available via a fixed line data connection.
The demand to deploy fourth generation networks is therefore strong and the coverage area of these networks, i.e. geographic locations where access to the networks is possible, is increasing rapidly and expected to continue to increase. However, although the coverage and capacity of fourth generation networks is expected to significantly exceed those of previous generations of communications networks, there are still limitations on network capacity and the geographical areas that can be served by such networks. These limitations may, for example, be particularly relevant in situations in which networks are experiencing high load and high-data rate communications between communications devices, or when communications between communications devices are required but the communications devices may not be within the coverage area of a network.
The anticipated widespread deployment of third and fourth generation networks has led to the parallel development of a number of new infrastructure architectures involving a variety of classes of devices, of wireless access point units and of applications which may require different data rates, coverage areas or transmission powers. Although there are applications which require high data rates to support their operation, there are some applications in which high data rates are not required. Indeed there are some applications which are expected to be provided by more simple, less complicated communications devices such as those supporting machine type communications (MTC). Such devices are also expected to be low power devices having applications which tend to be low-throughput and high-latency, and may include a relatively inexpensive low complexity transmitter and receiver. Such devices may also be deployed in locations in which radio communications conditions can make transmission and reception of signals more difficult. MTC applications are typified by semi-autonomous or autonomous wireless communication devices (i.e. MTC devices) communicating small amounts of data on a relatively infrequent basis. Examples include so-called smart meters which, for example, are located in a customer's house and periodically transmit information back to a central MTC server data relating to the customers consumption of a utility such as gas, water, electricity and so on. Other examples may include relay nodes which provide assistance to local terminals communicating with a base station.
3GPP has completed two Rel-13 Work Items on Internet of Things (IoT) namely, eMTC (Enhanced Machine Type Communications) and NB-IoT (Narrowband Internet of Things). These Work Items aimed at creating low cost devices that are power efficient and can operate in extended coverage e.g. such as inside basements.
In Rel-14, 3GPP agreed to enhance these types of IoT devices thereby introducing two Work Items namely, Rel-14 eNB-IoT (enhanced NB-IoT) [1] and Rel-14 fe-MTC (Further Enhanced MTC) [2]. One of the common objectives in these two WIs is positioning, which allows IoT devices to be tracked.
One of the positioning techniques considered for IoT (i.e. eNB-IoT and fe-MTC) is Observed Time Difference Of Arrival (OTDOA), where the User Equipment (UE), which may be an IoT device, an MTC device, or any kind of terminal device, measures the Reference Signal Time Difference (RSTD), i.e. the observed time difference between a target enhanced Node B (eNB) and a reference eNB. This is illustrated in FIG. 1. The UE 100 measures RSTD for two or more eNBs (i.e. involving 3 or more eNBs since one of them is the reference eNB) and sends these measurements to a Location Server 110 which is part of the core network. So, in the context of FIG. 1, the reference eNB is eNB1 105A, and the two or more eNBs are eNB2 105B and eNB3 105C. The Location Server 110 calculates the UE 100 position based on these RSTD measurements using the known location of the eNBs involved. That is, the Location Server performs a triangulation (involving at least 3 eNBs) to determine the UE location as shown in FIG. 1.
The accuracy of the UE 100 position is dependent upon the accuracy of the measured RSTD. For example, in FIG. 1, the time of arrival from eNB1 has an accuracy of ΔT1, the time of arrival of eNB2 has an accuracy of ΔT2 and the time of arrival for eNB3 has an accuracy of ΔT3. The accuracy of the time of arrival measurement is dependent upon the quality of the measured Reference Signal and the bandwidth of the Reference Signal.
The time of arrival can be estimated using a known signal, i.e. Reference Signals such as Cell-Specific Reference Signals (CRS), Primary Synchronisation Signals (PSS) or Secondary Synchronisation Signals (SSS). However, these reference signals (more generally "RS") experience inter-cell interferences and hence in LTE Rel-9, Positioning Reference Signals (PRS) were introduced.
FIG. 2 shows the RE (Resource Element) location of a set of PRS for an eNB within a Physical Resource Block (PRB) and the location occupied is dependent upon the eNB's Cell ID. Up to 6 different sets of PRS locations with different frequency shifts can be transmitted, hence up to 6 different eNBs can be measured at a time (assuming one eNB per frequency shift). It should be noted that the eNBs sharing the same frequency shift would have different sequences to distinguish among themselves. The PRS is transmitted over NPRS={1, 2, 4, 6} consecutive subframes with a period of TPRS={160, 320, 640, 1280} subframes. The NPRS consecutive subframes of PRS transmission is known as the Positioning Occasion. An example of the Positioning Occasion and the period TPRS are shown in FIG. 3, where the Positioning Occasion has length NPRS=4 subframes and occupies subframe 1, 2, 3 & 4.
NB-IoT and eMTC devices are low complexity devices. One route to achieving low complexity is to operate with a narrow bandwidth and a low sampling rate. However, the low sampling rate reduces the accuracy with which the position of a UE can be determined. The relationship between distance error, εd, and time error, εT, for a position derived from an RSTD measurement is (where 'c' is the speed of light):εd=c×εT
For a sampled signal, the time error is related to the sampling time. eMTC is a 1.4 MHz bandwidth system and a UE typically uses a sampling rate of 1.92 MHz (sample time=0.52 μs). NB-IoT is a 180 kHz bandwidth system with a typical sampling rate of 320 kHz. Hence the position inaccuracy of these systems, due to the sampling rate, are:eMTC: εd=156 mNB-IoT: εT=937 m
There are several possible implementations for deriving an RSTD measurement from a received signal, including correlation based techniques and techniques that create a time-domain channel impulse response.
FIG. 4 shows an example architecture 400 of a UE that creates a time domain channel impulse response in order to derive RSTD measurements. Based on the channel impulse response produced by the IFFT functions, the UE can estimate the arrival times, TeNB1, TeNB2, . . . TeNB6 of the signals from each eNB in the positioning set. RSTD measurements may then be derived based on these arrival time estimates.
In the example architecture 400 of FIG. 4, the PRS is received by antenna 405. The received signal is fed into a Radio Frequency Front End module 410. This amplifies, filters, downconverts and samples the received signal as would be appreciated by the skilled person. The sampled signal is fed into a Fast Fourier Transform (FFT) module 415. This produces a frequency domain representation of the received waveform from which the PRS signal can be extracted, as would be appreciated by a skilled person. The PRS signal from the output of the FFT module 415 is fed to an array of channel estimator modules (420A . . . 420N). In this discussion of the known system, there are six channel estimator modules in the array (one for each of the six eNBs whose PRS can be measured). Of course, any number is envisaged.
Referring back to FIG. 4, the output of each of the channel estimator modules 420A . . . 420N is fed into an Inverse Fast Fourier Transform (IFFT) module 425A . . . 425N. Each of these IFFT modules produces a channel impulse response for that particular eNB in the time domain. An example output of one of the IFFT modules 425A is shown in FIG. 5 as will be explained later. These channel impulse responses are provided to an RSTD calculation module 430 which calculates the RSTD for each eNB using a known technique and sends these calculations to the Positioning Server which determine the position of the UE.
In the architecture of FIG. 4, the UE produces channel impulse responses of the form shown in FIG. 5. The accuracy with which the channel impulse response can be resolved in the time domain is shown to be a function of the sampling rate of the system. For low sample rate systems, such as eMTC and NB-IoT, the accuracy of the determined channel impulse responses is compromised compared to systems operating at higher sample rates. This is primarily because by sampling at a low rate, the UE is more likely to miss the peak amplitude of the channel impulse response and it is the peak amplitude which is one mechanism to identify the distance to the eNB sending the PRS. Of course, and as would be appreciated, there are other methods of determining the distance to the eNB such as determining the time location of the first path in the channel impulse response that is greater than a threshold.
This is shown diagrammatically in FIG. 5, where a UE with a basic sample time Ts is shown in graph 1, a UE with a sample time of 2Ts is shown in graph 2 and a UE with a sample time of Ts/2 is shown in graph 3.
However, it is undesirable to increase the sample rate within the UE (especially eMTC and NB-IoT type devices) because this increases the battery consumption and the complexity of the device. Therefore, it is desirable to improve the accuracy of positioning for eMTC and NB-IoT, without increasing device complexity (i.e. without increasing the sampling rate of the device).
It is an aim of the present disclosure to address this issue.

Methods and apparatuses for communicating position reference signals


A method is disclosed, comprising dividing an outgoing message into a plurality of shards, and generating an error correction code corresponding to the outgoing message. The method may also include transmitting a first shard and a second shard of the plurality of shards to a core network via a radio access network (RAN). The first shard and the second shard are encrypted and the second shard is transmitted after a configurable time interval after transmitting the first shard.

International Mobile Subscriber Identity (IMSI) catchers, also known as cell-site simulators, pose a privacy threat to mobile phone users because they trick mobile phones within a certain radius into connecting to the IMSI catcher instead of an actual cellular tower. The IMSI catcher provides valuable assistance to law enforcement agencies for various public safety objectives, for example, a fugitive apprehension effort, a complex narcotics investigation, or to locate or rescue a kidnapped child. Thus, IMSI catchers can provide a public benefit when used for legal ends. But, when an IMSI catcher is available to hackers, the IMSI catcher may be used to steal valuable information of mobile phone users within a certain radius of the stingray tower. The mobile phone user may perform transactions requiring privacy and security while being connected to the IMSI catcher, resulting in the IMSI catcher storing private and sensitive information from the transactions. The hackers may then misuse the stolen information for malicious purposes.
In the drawings, like reference numbers generally indicate identical or similar elements. Additionally, generally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears.

Multi cell phone tower information transfer security


A fabrication method which can improve electrical properties, shorten processing time, and reduce the thickness of a chip package by achieving an ultra-thin fine circuit pattern. The method for fabricating a printed circuit board includes: providing an insulating material; forming in the insulating material at least one via-hole for interlayer electrical connection; ion beam treating the surface of the insulating material having the via-hole formed therein; forming a copper seed layer on the surface-treated insulating material using a vacuum deposition process; and plating a copper pattern on the copper seed layer to form a circuit pattern.

1. Field
The present invention relates to a printed circuit board and a fabrication method thereof, which can improve electrical properties, shorten processing time, and reduce the thickness of a chip package by achieving an ultra-thin fine circuit pattern.
2. Description of the Related Art
As semiconductor chip manufacturing technology has advanced, the development of technology for the fabrication of package boards on which semiconductor chips are mounted has been actively conducted.
Specifically, after the middle of the 1990s, ball grid arrays (BGAs), which adopt a wire bonding process to connect ICs with boards, were commonly used. However, due to an increase in the number of I/O pins of semiconductor ICs, these methods have a limitation in that it is impossible to mount high-speed, high-performance ICs having small sizes.
Thus, technology of using flip chip interconnects to electrically connect ICs with boards was recently developed. Package products mounted on boards using the flip chip interconnect technology are collectively called "FCIP" (Flip Chip in Package).
It is known that, in the case of substrates for such FCIP, the formation of high-density multilayer circuits having a circuit line width of less than 35 μm/35 μm is required. Methods for forming such HDI (high-density interconnection) may include laser build-up welding.
In this method, BT, FR-4 or other resins are impregnated into woven glass fabric to make a core. On both sides of such a core, a copper foil is laminated to a thickness of 18-35 μm to form an inner layer circuit, and then a subtractive process or a semi-additive process is performed to fabricate a printed circuit board.
The method for forming build-up patterns on a board having an inner layer circuit pattern formed thereon is shown in FIGS. 1A to 1F.
FIGS. 1A to 1F are process cross-sectional views illustrating the prior method for fabricating a printed circuit board.
As shown in FIG. 1A, an inner layer circuit pattern 12 is first formed on both sides of a core 10 using a general process.
In this respect, the core 10 is made of a copper-clad laminate (CCL), and as the insulating material of CCL, FR-4 or epoxy resin, impregnated into woven glass fabric, is mainly used.
After the inner layer circuit pattern 12 is formed, as shown in FIG. 1B, an ink-type thermosetting resin 14 is applied on the core board having the inner layer circuit pattern 12 formed thereon, or a dry film-type resin is attached to the core board. Then, the applied or attached resin is cured.
Then, as shown in FIG. 1C, a given location of the board structure is irradiated with a laser beam to form a via-hole 18.
After the via-hole 18 is formed, as shown in FIG. 1D, the surface of the board having the via-hole 18 formed therein is roughened and subjected to CZ treatment. Then, a copper seed layer 20 is formed on the surface of the board using an electroless copper plating process. In this respect, the copper seed layer 20 is formed after a Ni—Cr tie-layer (not shown) is formed.
After the copper seed layer 20 is formed, a dry film 22 is attached on the copper seed layer 20, and then, as shown in FIG. 1E, the portion where a circuit pattern is to be formed is exposed through a conventional photo-etching process comprising exposure and development.
Then, a conductive layer 24 is formed using a copper electroplating process, followed by removal of the dry film 22. After the dry film 22 is removed, the portion of the copper seed layer 20 on which the conductive layer 24 was not formed is removed using a flash etching process, thus forming an outer layer circuit pattern 26 as shown in FIG. 1F.
After the outer layer circuit pattern 26 is formed, in order to form a multi-layer printed circuit board, an adhesive layer and an insulating layer are sequentially formed on the outer layer circuit pattern 26 and are pressed with a press.
Then, after the outermost layer circuit pattern is formed in the outermost layer, the outermost layer circuit pattern, which is connected to an external terminal, is exposed through a solder resist opening process, and a gold plating layer is formed on the exposed outermost layer circuit pattern.
However, this prior printed circuit board has problems in that, because FR-4 or epoxy-based insulating material having a high dielectric constant (higher than 4.5), a high loss coefficient (higher than 0.05), and a high propagation delay time (higher than 180 ps/in), is used, not only is a large amount of heat generated, but also the electrical properties are reduced, due to the reduction of signal transmission speed and the loss of the transmitted signal. Also, there is a problem in that, because CCL having resin impregnated into woven glass fabric is used in the core, the thickness of the package is increased.
Moreover, the method of fabricating the printed circuit board using sputter Flexible Copper Clad Laminate (FCCL) according to the prior art has a problem in that, because the copper seed layer is formed after the formation of the Ni—Cr tie-layer, a process of depositing the tie-layer and a process of etching the tie-layer are required, and thus a long processing time is needed.
Furthermore, the method for fabricating the printed circuit board according to the prior art has problems in that, because the insulating layer is deposited on the inner layer circuit pattern 12 using an epoxy or acryl-based adhesive layer in order to fabricate a multilayer printed circuit board, not only are a process time and process cost for forming the adhesive layer increased, but also the excellent electrical properties of the insulating layer are reduced due to the adhesive layer, and the thickness of the chip package is increased.
In addition, the method for fabricating the printed circuit board according to the prior art has a problem in that a large amount of waste, such as wastewater and contaminants, are generated in the pretreatment process, such as CZ treatment or desmearing treatment, and the wet process such as electroless copper plating for forming the copper seed layer, thus causing environmental contamination.

Method of manufacturing printed circuit board


Water is stored in a metal can, and water vapor is supplied to a separator through an opening in a washer. The separator is an alkali metal salt in a sulfonated synthetic resin membrane, and KOH aqueous solution is used as the electrolyte, and the sensing electrode and the counter electrode are Pt—C, and solid proton conductive membranes are placed between the electrodes and the separator.

A gas sensor using solid proton conductive membrane is known (Documents 1 and 7). In this gas sensor, a proton conductive membrane is interposed between a pair of electrodes, and water vapor is fed from a water reservoir. After that, the present inventors considered the possibility of applying the structure of the gas sensor using a solid proton conductive membrane to a gas sensor using a liquid electrolyte.
In a gas sensor using a liquid electrolyte, the electrolyte is held in a separator, and the electrolyte is replenished from a reservoir of the electrolyte by means of a wick. As sulfuric acid is used as the electrolyte, a metal housing can not be used. Furthermore, in an atmosphere of high humidity, sulfuric acid will absorb moisture and may overflow from the reservoir.
Document 2 proposes a liquid electrochemical gas sensor using no wick. Here, sulfuric acid is stored in a water reservoir, and sulfuric acid is arranged to absorb moisture when the humidity is high and release moisture when the humidity is low, thus substantially maintaining the humidity at a constant level in the gas sensor. As a result, the electrolyte in the separator is prevented from drying. Document 3 proposes to set a deliquescent salt such as LiCl in a water reservoir so as to substantially keep the humidity at a constant level in the gas sensor. When sulfuric acid or a deliquescent salt is used, however, there is a possibility that in an atmosphere of high temperature and high humidity or the like the liquid electrolyte may overflow from the water reservoir.
Document 4 discloses a separator wherein colloidal silica and PTFE (polytetrafuluoloethylene) are carried on a paper-like glass filter. Here, it is understood that hydrophilic channels for maintaining the liquid electrolyte are provided by colloidal silica, and hydrophobic channels for diffusing gas are provided by PTFE.
Document 5 discloses an O2 sensor using a liquid electrolyte of KOH or H2SO4, and it is reported that the characteristics will drift when KOH is used.    Document 6 discloses a CO sensor using an MgSO4 aqueous solution.    Document 1: WO 02/097420A1    Document 2: WO 01/14864A1    Document 3: U.S. Pat. No. 5,958,200    Document 4: U.S. Pat. No. 4,587,003    Document 5: U.S. Pat. No. 5,240,893    Document 6: U.S. Pat. No. 5,302,274    Document 7: U.S. Pat. No. 6,200,443


The high intensity illuminator of the invention includes a mounting fixture, a receiving surface spaced from the mounting fixture, and a plurality of semiconductor illumination sources which are implemented, most preferably, by light emitting diodes or laser diodes. Each illumination source is operable for emitting an outwardly-diverging illumination cone along an axis of illumination of the source at a predetermined illumination wavelength. The plural illumination sources are mounted on the mounting fixture such that their illumination cones are overlappingly coincident on a selected portion of the receiving surface to provide at the receiving surface portion a highly uniform illumination of high intensity at the predetermined wavelength.

The need for high intensity, spatially uniform illumination sources is particularly acute in optical metrology instrumentation such, for example, as interferometric microscopes. In the past, sources of filtered and unfiltered white light and arc sources, gas lasers, laser diodes, and light emitting diodes (LED's)--each for the most part lifted, without significant modification or effective adaptation, from standard optical microscopes--have been employed. However, the acquisition of accurate measurement data using interferometric microscopes requires illuminator properties that notably differ from those suitable for standard optical microscopes.
For example, phase shifting interferometry instruments are routinely used in precision automated quality and process control applications in which data is repeatedly taken without direct operator intervention; the illumination source must accordingly be extremely rugged and long lived. Moreover, interferometric data is generally obtained using image sensors and, since the illumination wavelengths should be selected to conform to the spectral sensitivity and resolution requirements of the sensor, the ability of the human eye to image or view the illumination is generally irrelevant to wavelength selection.
Depending upon sensor type, interferometric illuminators may require shuttering during data readout and should therefore be 100 percent modulatable at relatively high speeds since, in typical applications, multiple frames of data are taken in synchronization with a reference surface phase shifter. In addition, the interference fringe contrast, rather than feature contrast, should be maximized and the fringes must have negligible contrast variation over the range of reference surface axial motion; accordingly, the temporal coherence length of the illumination should be long as compared to the reference surface axial motion.
Further requirements of interferometric microscope illumination are that its mean wavelength be precisely known, that its spectral properties and intensity not vary (i.e. high temporal uniformity) as data is being taken, that it be sufficiently intense as to reduce data acquisition time and, correspondingly, sensitivity to vibration, that its source not be a direct or indirect generator of measurement-disturbing vibrations, that it be spatially incoherent so as to reduce optical artifact sensitivity and speckle, and that it be sufficiently uniform as to provide a well understood spatial coherence function. It is also preferred that the illuminator provide ready access to a multiplicity of different wavelengths of light for extending the instrument's step measurement size.
All heretofore known and used illumination sources for optical metrology instrumentation fail to meet these multiple concurrent requirements. For example, filtered white light and arc sources satisfy the coherence requirements and are simple sources of multiple illumination wavelengths. However, they are short lived, are physically large with much associated optics, require mechanical shuttering and wavelength selection systems, and generate undue amounts of heat.
Gas laser sources satisfy the wavelength precision and stability requirements and are cooler and longer lived than incandescent sources. Moreover, unlike filtered white light or arc sources, the long temporal coherence properties of gas lasers permit their use with non-equal path (i.e. FIZEAU) type interferometers. On the other hand, they suffer from the need to reduce their spatial coherence, as by associated mechanical rotating diffuser disks which are both physically large and a potential source of vibration, they require mechanical shuttering systems, and they have no intrinsic wavelength selection capability. In addition, laser moding from thermally-induced cavity variations can be a major source of intensity fluctuations which are difficult to remove.
Laser diodes satisfy the wavelength precision requirement, are easily modulated, and are cooler in operation than arc, incandescent and gas laser sources and much longer lived. Moreover, the temporal coherence properties of index guided solid state lasers is comparable to gas lasers, and the intensity of laser diodes is sufficiently constant if their temperature is stabilized and optical feedback is provided. Although they have no intrinsic wavelength selection, the small size of laser diodes permits the use of multiple diodes for multiple wavelengths; however, the wavelengths vary from diode to diode and not all wavelengths, particularly short wavelengths, are available. Furthermore, laser diodes are high static sensitive and therefore require special handling precautions and circuitry and, as with gas lasers, they also suffer from laser moding and the need to break the spatial coherence as, for example, through the use of mechanical rotating diffuser disks.
Light emitting diode sources can potentially provide the advantage of long life, high speed modulation capability and low cost. Illuminators using LED's for standard microscopes, as for example described in U.S. Pat. No. 4,852,985, are not simultaneously of sufficient uniformity and intensity to provide a cost-effective source for automated precision optical metrology instrumentation. Imaging of a two-dimensional array of light emitting diodes onto a diffuse surface in an interferometric measurement apparatus requires high numerical aperture optics for good collection efficiency and results in a large, relatively expensive source with a sinusoidally-varying intensity distribution on the diffuser surface on which the semiconductors are imaged. Improvements to uniformity can be realized only at the cost of a thicker, more diffuse surface--which unavoidably and undesirably reduces illumination intensity. In addition, temporal intensity variations due to common mode electrical power fluctuations not visible to the eye can completely destroy interferometric data.
There is, accordingly, an unmet need for an illuminator that is especially well-suited for and concurrently satisfies the various requirements of automated precision optical metrology instrumentation, particularly for interferometric microscopes.