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GoodWill - Campbell, CA
in Permanent Charity Donation Locations
A Goodwill store in Campbell, CA.
posted by: saopaulo1
location: California
date approved: 12/27/2012
last visited: never
Goodwill Air Base Blvd Thrift Store - Montgomery, AL
This Goodwill Retail Store and Donation Center is located on Air Base Boulevard in Montgomery, Alabama.
posted by: xptwo
location: Alabama
date approved: 12/20/2012
Big Brothers Big Sisters of West Island/Grands Freres Grandes Soeurs de l'Ouest De L'Ile at Dorval, Quebec
in Big Brothers Big Sisters
The office of Big Brothers Big Sisters of West Island is located in Dorval, Quebec, a suburb of the Island of Montreal.
posted by: Bird is the Word
location: Quebec, Canada
date approved: 12/19/2012
last visited: 8/16/2014
Midlothian Family YMCA - Midlothian, VA
in YMCA / YWCA
This YMCA is located in southern Midlothian.
posted by: bluesnote
location: Virginia
date approved: 12/17/2012
last visited: 12/17/2012
American Red Cross Carriage Place Donor Center - Columbus, Ohio
in Blood Donation Centers
4820 Sawmill Road
Columbus, OH 43235
posted by: DougandSandra
location: Ohio
Ronald McDonald House - Brookline, MA
in Ronald McDonald Houses
The Ronald McDonald House in Brookline is near the Longwood Medical Center, which has many hospitals in one area, including Children's Hospital.
posted by: NorStar
location: Massachusetts
date approved: 12/16/2012
Salvation Army Family Services - Trail, British Columbia
in Salvation Army Locations
Salvation Army Family Services is located at 730 Rossland Avenue, in the Gulch.
posted by: BK-Hunters
location: British Columbia, Canada
date approved: 12/7/2012
last visited: 1/30/2014
Lowell Animal Shelter - Lowell AR
in Humane Societies and Rescues
This animal shelter is located in the City Complex in Lowell, Arkansas.
posted by: Where's George
location: Arkansas
YMCA - Stillwater, OK
The local "Y" in Stillwater, OK. Old building in need of repairs but still used. One picture is taken from the east, looking at the main entrance. The picture of the sign is taken from the south, looking past the end of the pool from the parking lot.
posted by: sshelle
location: Oklahoma
date approved: 12/3/2012
last visited: 12/3/2012
Frederick County Habitat Restore
The local affiliate established a thrift store in the former auto dealer showroom and garage in 2011.
posted by: vhasler
location: Maryland
date approved: 11/28/2012
last visited: 3/16/2013
S.P.C.A - Trail, British Columbia
The Trail and Region Animal Care Facility - S.P.C.A is located at 7700 Highway 3B. There is a large sign on the highway pointing the way to the facility.
date approved: 11/27/2012
last visited: 2/2/2014
YWCA of Westmoreland County - Greensburg, Pennsylvania
The YWCA of Westmoreland County is located at 424 North Main Street in Greensburg City, Westmoreland County, Pennsylvania
posted by: outdoorboy34
location: Pennsylvania
date approved: 11/23/2012
American Red Cross Greater Rochester (NY) Chapter
The blood donation center in this waymark occupies a wing of the Red Cross Building on the corner of Prince Street and College Street, Rochester, NY 14607
posted by: sagefemme
location: New York
date approved: 11/20/2012
Salvation Army Building (1930-1968) - Salem, Oregon
Historic location of the Salvation Army in downtown Salem
posted by: ddtfamily
location: Oregon
date approved: 11/13/2012
last visited: 2/17/2013
The Salvation Army Community Center - Sunnyvale, CA
This community center serves Sunnyvale and Mountain View.
date approved: 10/26/2012
Services animaliers de la Rive-Sud, Longueuil, Qc
Les Services Animaliers de la Rive-Sud est un Organisme à But Non Lucratif qui a pour mission de fournir soins et pension temporaires aux animaux de compagnie perdus, abandonnés, blessés, errants, en détresse ou saisis.
posted by: gemeloj
date approved: 10/22/2012
last visited: 10/25/2014
Salvation Army Flea Market - Lahti, Finland
Salvation Army Flea Market @ Liipola, Lahti
posted by: Jabozozo
location: Finland
date approved: 10/17/2012
last visited: 10/22/2012
Salvation Army Thrift Store – Trail, British Columbia
This Salvation Army Thrift Store is located at 1297 Cedar Avenue.
last visited: 2/4/2014
Mission Ministries Box - Hayward, CA
A box for Mission Ministries in Hayward, CA.
date approved: 10/11/2012
Blutspendedienst Harburg / Hamburg, Germany
Die Harburger Filiale des Blutspendedienst Hamburgs
posted by: Astartus
location: Hamburg, Germany
last visited: 7/20/2015
Big Brothers Big Sisters of Lane County - Eugene, Oregon
The mission of Big Brothers Big Sisters of Lane County (BBBS) is to connect youth to their community through mentors who inspire and motivate youth and families toward personal growth, healthy relationships, and meaningful opportunities.
posted by: DougK
date approved: 10/6/2012
last visited: 9/1/2014
Blood Donation Center Lahti
Blood Donation Center Lahti.
posted by: marcius
date approved: 10/4/2012
last visited: 6/14/2014
YMCA - Salem, Oregon
The YMCA building in Salem, Oregon
date approved: 9/30/2012
YMCA -- Garland TX
The YMCA of Metropolitan Dallas has a branch in Garland, on North Garland Ave near Buckingham Road.
posted by: Benchmark Blasterz
location: Texas
date approved: 9/26/2012
last visited: 9/1/2012
YMCA / YWCA - Gamla Stan, Stockholm, Sweden
This building houses both YMCA and YWCA, located on Skeppsbron, along the waterfront of Gamla Stan, in Stockholm, Sweden.
posted by: Chasing Blue Sky
location: Stockholm, Sweden
date approved: 9/22/2012
last visited: 4/19/2013
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text:
Just a quick note to let everyone know that our new benchmarking script now supports OSX 10.6 on Intel hardware. That means you can run one simple command and get all of the sequential and random INSERT and SELECT performance statistics about your database performance. As usual the script is open source and released under the new BSD license. Give is a try by downloading now! See the download page for more details.
Posts Tagged hardware
You can download the first release of the benchmarking script here: http://code.google.com/p/dbbenchmark/
Please read the README file or consult the Support page before running the benchmarks.
Welcome to DBbenchmarks.com, a publicly accessible database that tracks anonymously submitted data about MySQL server performance. You can use this site to see research the performance of certain types of hardware when running MySQL. Our open-source benchmarking script is free to own and use, we only ask that you allow the script to connect to this database and submit the results. All results and data collected is anonymous and viewable on this site. We only track performance data from MySQL – you can see the list on the About page.
Check out the database of benchmarks here: [link]

subset: commoncrawl


text:
Tom Ford
Black Orchid Eau De Parfum 50ml
Product Actions
TOM FORD BLACK ORCHID is a luxurious scent. While sultry woods and rich fruit accords help to bring out the skin's natural perfume, the jet-black, art-deco inspired bottle adds to the fragrances overall glamour.
1.7 oz/50mlStyle # 173575000
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If you prefer email, we can be reached anytime at firstname.lastname@example.com.
Our Shipping & Returns Policy can be viewed here.


text:
Rising tuition costs at two-year colleges are outpacing increases in household incomes across the country, making it difficult for students to get bachelor's degrees, according to a report released today.
The contrast is especially stark in Virginia, according to the report from the National Center for Public Policy and Higher Education. From 1999 to 2009, median household income, adjusted for inflation, rose 6 percent statewide while tuition at public two-year colleges increased 94.4 percent.
Over the same time, tuition at four-year state institutions rose more than 60 percent, the report says.
Nationwide, the affected students - more likely to be minorities, from low-income backgrounds and the first in their families to attend college - are 15 percent less likely to finish a bachelor's degree, the report found.


text:
Are you looking for a job that you will love and feel good about? At SEIA, our staff arrives to the office every morning knowing that their work improves our country's energy independence and helps to revitalize our economy through the creation of thousands of U.S. jobs.
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text:
So this site I've never heard of interviewed Greg "Ghostcrawler" Street, the guy who nerfed your Starsurge and stole your children. Here's what's up for the next patch:
Patch 4.2, y'all
This edit will also create new pages on Giant Bomb for:Beware, you are proposing to add brand new pages to the wiki along with your edits. Make sure this is what you intended. This will likely increase the time it takes for your changes to go live.
Comment and Save
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text:
Notts chief executive Jim Rodwell blasts referee over call off
Posted: December 22, 2012|
NOTTS County chief executive Jim Rodwell has blasted the decision to call off the Magpies' league game against Leyton Orient at Meadow Lane today.
Rodwell was furious with referee Jeremy Simpson, who held two pitch inspections, at midday and 1pm, before calling the game off.
The pitch was perfectly playable and Rodwell said: "I am astonished at the decision of today's match referee to call the game off.
"In all my years in football I have never been more surprised at a decision.
"It quite simply beggars belief that a professional match official could come to this conclusion.
"Both managers and both sets of players wanted to play the game and were more than happy with the condition of the pitch.
"It appears that the only person in the stadium who thought that the game was a danger to the players was the referee."


text:
|I'm much colder than I appear
|Adam pensively reflecting on life
Last weekend we also went to Tattooed Moose for the first time. I've heard way too many good things about Mike's Duck Club that I couldn't wait any longer. Seriously, this sandwich lives up to the hype. Husk introduced me to the wonders of duck confit, but they now have a serious rival with the duck club. I forgot to take a picture of my meal, but here's on courtesy of Food GPS.
The Duck Club comes loaded with duck confit, apple smoked bacon, smoked cheddar, garlic alioli, lettuce, tomato, and red onion on Sweet Hawaiian bread. It is incredible. I really appreciated the bread; it was toasted but never had any problems with scratching the roof of your mouth. Clearly, this meal may be a baby heart attack, but life is all about balance, right? I'll just juice my breakfast the next time I do this.
On the other hand, I did get a picture of Adam's meal. He is ridiculous. He ordered the Lucky Sub #1, which is BBQ braised pork belly, house made kimchi, tomatoes, cucumbers, crispy onions, cilantro, and sweet red chili sauce. Unfortunately, Adam missed that the sandwich also included wasabi mayonnaise. Now both of us can't do wasabi. I love, love, love spicy food - but I hate wasabi. It's something about the taste. I find it unbearable. As does Adam. Whenever we order sushi we have to sometimes avoid pieces that the wasabi may have touched. You may call us babies, but I just can't stand the stuff.
So when Adam discovered his lovely sandwich was covered in wasabi, this is what happened:
I went to dinner with a 5-year-old. Apologies Tattooed Moose, he loved the rest of the sandwich.
Side note: Eat the fries! They're fried in duck fat! If you cannot tell, I can't get enough of duck. ;)
Tonight I'm off to Coast for restaurant week with my roommates! Have y'all been to any special restaurants this week?


text:
Neighbors and colleagues remembered Hoffman as a "neighborhood guy" and "sweet dad."
Katherine Adams, 48, disappeared earlier in July, police said.
A Bank Street Citi Bike Share outpost will endanger residents of a nearby building, the suit says.
The action star grew up in the West Village artists' complex on Bethune Street.
The beloved mural at the Waverly Inn has been restored after a June 25 fire.
The West Village restaurant remained closed Tuesday as workers hauled out scorched debris.
A fire broke out Monday in the basement of the Bank Street building housing the Waverly Inn.
The Department of Sanitation is making changes to recycling pick-up days in parts of the West Village, Greenwich Village and NoHo.
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A system and method for the detection and three dimensional imaging of absorption and scattering properties of a medium such as human tissue is described. According to one embodiment of the invention, the system directs optical energy toward a turbid medium from at least one source and detects optical energy emerging from the turbid medium at a plurality of locations using at least one detector. The optical energy emerging from the medium and entering the detector originates from the source is scattered by the medium. The system then generates an image representing interior structure of the turbid medium based on the detected optical energy emerging from the medium. Generating the image includes a time-series analysis.
1. A system for use in tomographic imaging of a scattering medium, comprising:
a plurality of energy sources, each energy source emitting a respective signal for imaging the scattering medium;
wherein the plurality of energy sources emit their respective signals sequentially and the respective signals are scattered by the scattering medium and emerge from the scattering medium; and
a plurality of detectors for detecting the respective signals that emerge from the scattering medium for use in measuring dynamic properties of the scattering medium in a time series of images using optical tomography.
2. The system of
an imaging head on which the energy sources and the detectors are arranged;
wherein the energy sources and the detectors are arranged in a plurality of linear arrays to enable reconstruction of a corresponding plurality of 2-D images of the scattering medium.
3. The system of
4. The system of
5. The system of clam 1, wherein the energy sources include at least one of a non-laser optical source LED, high-pressure incandescent lamp, laser diode, solid state laser, titanium-sapphire laser, ruby laser, dye laser, electromagnetic source acoustic energy source, acoustic energy produced by optical energy, optical energy, and combinations thereof.
6. The system of
7. The system of
8. The system of
9. The system of
10. A system for use in optical tomographic imaging of a scattering medium comprising:
at least one energy transmissive fiber bundle coupled to at least one energy source;
the at least one energy transmissive fiber bundle emitting energy from the at least one energy source, and detecting the energy after it is scattered by the scattering medium;
an imaging head for holding the at least one energy transmissive fiber bundle; and
a detection system for collecting data regarding the optical dynamic properties of the scattering medium from the detected energy;
wherein the imaging head undergoes uniform expansion and contraction to accommodate different size scattering mediums.
11. The system of
12. The system of
13. The system of
14. A method of imaging a scattering medium using optical tomographic imaging, comprising:
(a) exposing the scattering medium to energy from a plurality of energy sources that sequentially emit the energy; and
(b) detecting the energy, via a plurality of detectors, after the energy has been scattered by the scattering medium for use in measuring dynamic properties of the scattering medium in a time series of images using optical tomography.
15. The method of
16. The system of
17. The system of
18. The system of
19. An imaging head, comprising:
a pad;
a plurality of source means for delivering optical energy to a medium; and
a plurality of detector means for detecting optical energy emerging from the medium; wherein:
the source means and detector means are attached to the pad in a plurality of rows and columns wherein the plurality of source means are arranged to form at least two unique imaging planes, an imaging plane being between defined by a plane substantially perpendicular to the pad and passing through at least two source means and one detector means; and
the source means and detector means are arranged in first and second patterns in alternating rows, the first pattern comprising one source means followed by three detector means followed by one source means followed by three detector means, and the second pattern comprising a shifted version of the first pattern.
20. The imaging head of
21. The imaging head of
22. The imaging head of
23. The imaging head of
24. The imaging head of
25. The imaging head of
26. The system of
27. The system of
28. The detection system of
29. The detection system of
30. The system of
31. The method of
32. The method of
33. The method of
34. The system of
35. The system of
36. The system of
37. The system of
38. The system of
39. The system of
40. The system of
41. The system of
42. The system of
43. The system of
44. The system of
45. The system of
46. The system of
47. The method of
48. The method of
49. The method of
50. The method of
51. The system of
an imaging head on which the energy sources and the detectors are arranged;
wherein the energy sources and the detectors are arranged in a plurality of linear arrays to enable reconstruction of a 3-D image of the scattering medium.
This application claims the benefit under 35 U.S.C. Ï 120 of prior U.S. Provisional Patent Application Serial Nos. 60/153,926 filed Sep. 14, 1999, entitled DYNAMIC TOMOGRAPHY IN A SCATTERING MEDIUM and 60/154,099 filed Sep. 15, 1999, entitled DYNAMIC TOMOGRAPHY IN A SCATTERING MEDIUM.
This application is related to copending application Ser. No. PCT/US00/25136 filed on the same date as this application, entitled "METHOD AND SYSTEM FOR IMAGING THE DYNAMICS OF SCATTERING MEDIUM" by inventor R. Barbour is hereby incorporated by reference (hereinafter the "Barbour 4147PC2 application"). The counterpart U.S. patent application is app. Ser. No. 10/088,190, filed Mar. 14, 2002.
This application is related to copending application Ser. No. PCT/US00/25157 filed on the same date as this application, entitled "METHOD AND SYSTEM FOR ENHANCED IMAGING OF A SCATTERING MEDIUM" by inventors R. Barbour and Y. Pei and is hereby incorporated by reference (hereinafter the "Barbour 4149PC1 application"). The counterpart U.S. patent application is app. Ser. No. 10/088,185, filed Mar. 14, 2002.
This application is also related to copending application Ser. No. PCT/US00/2515, filed on the same date as this application, entitled "IMAGING OF SCATTERING MEDIA USING RELATIVE DETECTOR VALUES" by inventor R. Barbour and is hereby incorporated by reference (hereinafter the "Barbour 4149PC2 application"). The counterpart U.S. patent application is app. Ser. No. 10/088,192, filed Mar. 14 2002.
This invention was made with U.S. Government support under contract number CA-RO166184-02A, awarded by the National Cancer institute. The U.S. Government has certain rights in the invention.
The invention relates to a system and method for tomographic imaging of dynamic properties of a scattering medium, which may have special application to medical imaging, and in particular to systems and methods for tomographic imaging using near infrared energy to image time variations in the optical properties of tissue.
Contrary to imaging methods relying on the use of ionizing radiation and/or toxic/radioactive contrast agents, near infra-red (NIR)-imaging methods bear no known risk of causing harm to the patient. The dose of optical intensity used remains far below the threshold of thermal damage and is therefore safe. In the regime of wavelength/intensity/power used, there are no effects on patient tissue that accumulate with increasing NIR dose due to over-all irradiation time.
The general technology involved in optical tomography is developed and understood, so that, compared to other cross-sectional imaging techniques such as MRI, X-ray CT, and the like, only moderate costs and relatively small-sized devices are required. Optical tomography especially gains from the development of small, economical, yet powerful semiconductor lasers (laser diodes) and the availability of highly integrated, economical off-the-shelf data processing electronics suitable for the application. Moreover, the availability of powerful yet inexpensive computers contributes to the attractiveness of optical tomography since a significant computational effort may be necessary for both image reconstruction and data analysis.
Optical tomography yields insights into anatomy and physiology that are unavailable from other imaging methods, since the underlying biochemical activities of physiological processes almost always leads to changes in tissue optical properties. For example, imaging blood content and oxygenation is of interest. Blood shows prominent absorption spectra in the NIR region and vascular dynamics and blood oxygenation play a major role in physiology/pathology.
However, cross-sectional or volumetric imaging of dynamic features in large tissue structures is not extractable with current optical imaging methods. At present, whereas a variety of methods involving imaging and non-imaging modalities are available for assessing specific features of the vasculature, none of these assess dynamic properties based on measures of hemoglobin states. For instance, detailed images of the vascular architecture involving larger vessels (>1 mm dia.) can be provided using x-ray enhanced contrast imaging or MR angiography. These methods however are insensitive to hemoglobin states and only indirectly provide measures of altered blood flow. The latter is well accomplished, in the case of larger vessels, using Doppler ultrasound, and for near-surface microvessels by laser Doppler measurements, but each is insensitive to variations in tissue blood volume or blood oxygenation. Ultrasound measurements are also limited by their ability to penetrate bone. Other methods are available, (e.g., pulse volume recording, magnetic resonance (MR) BOLD method, radioscintigraphic methods), and each is able to sample, either directly or indirectly, only a portion of the indicated desired measures.
Thus, there is a need for a system and method of data collection providing cross-sectional or volumetric imaging of dynamic features in large tissue structures
The present invention provides a system and method for generating an image of dynamic properties in a scattering medium. The system includes an energy source, such as a NIR emitting source, and a detection system to measure received energy. In an exemplary embodiment, the detection system has at least one photo-detector such as a photodiode, a means for rapid adjustment of signal gain, and a device for retaining a measured response in order to investigate the dynamic variations in the optical properties of tissues. Depending on the implementation, the detection system further may also include at least one means for separating a plurality of signals from the photo-receiver when multiple energy sources are used simultaneously. This simultaneous use of multiple energy sources allows the use of different wavelengths and/or different source locations at the same time.
In one implementation using optical tomographic imaging, a specimen is exposed to NIR light emitted from at least one laser diode. Furthermore an imaging head may be utilized that contains means for positioning at least one source location and / or at least one detector location with respect to the medium. The energy detector may use an energy collecting element, such as an optical fiber to transmit the received energy. The energy detector is responsive to the energy or light emerging from the specimen. In accordance with the invention, the signal from the detector is selectively enhanced in gain to increase the dynamic measurement range. The method may further include separating via at least one lock-in amplifier a plurality of signals generated by multiple energy sources. In addition, the method allows simultaneous measurements of signals produced by the NIR light by means of a sample-and-hold circuit when more than one detector fiber is used.
For a better understanding of the invention, together with the various features and advantages thereof, reference should be made to the following detailed description of the preferred embodiments and to the accompanying drawings wherein:
FIG. 1 is a block diagram of one embodiment of a system according to the invention,
FIG. 2 is a block diagram illustrating one implementation of the system in FIG. 1;
FIG. 3 is a perspective view of a servo-motor apparatus useful in this invention to illuminate a number of fiber bundles with a single energy source;
FIG. 4 is a schematic illustration of the disposition for examining human tissue such as a human breast;
FIG. 5 is a schematic illustration of a planar imaging head useful in one embodiment of the invention;
FIG. 6 is one embodiment for the source detector arrangement on the imaging head shown in FIG. 5;
FIG. 7 is an illustration of a spherical imaging head useful in practicing the invention;
FIG. 8 is a block diagram of a detector channel useful in practicing the invention;
FIG. 9 is a graphical representation of one implementation of a timing scheme used in the system of FIG. 1;
FIG. 10 is a diagram illustrating the sequence of certain events in a multiple channel embodiment of the invention,
FIG. 11 is a schematic illustration of the physical arrangement of multiple detector channels used in a preferred embodiment of the invention;
FIG. 12 is a circuit diagram of one detector channel used in FIG. 11; and
FIG. 13 is a circuit diagram of one implementation of the lock-in module used in FIG. 12.
The objective of the invention is to provide a system and method capable to extract dynamics in properties of a scattering medium. The use of the invention's system and method has several applications including, but not limited to, medical imaging applications. Although the methods described herein focus on tomographic imaging the dynamic properties of hemoglobin states and tissue using optical tomography, with an imaging source generating multiple wavelengths in the NIR region, it is appreciated that the invention is applicable to any medium that is able to scatter the propagating energy from any energy source, including external energy sources such as those sources located outside the medium and/or internal sources such as those energy sources located inside the medium. For example, other media includes, but are not limited to, medium from mammals, botanical life, aquatic life, or invertebrates; oceans or water masses; foggy or gaseous-atmospheres; earth strata; industrial materials; man-made or naturally occurring chemicals and the like. Energy sources include, but are not limited to, non-laser optical sources like LED and high-pressure incandescent lamps and lasers sources such as laser diodes, solid state lasers such as titanium-sapphire laser and ruby laser, dye laser and other electromagnetic sources, acoustic energy, acoustic energy produced by optical energy, optical energy, and any combinations thereof
Similarly the means to detect the signal produced by the energy source is not limited to photodiode implementation discussed in one of the preferred embodiments further described herein. Other detectors can be used with the principles of the present invention for the purpose of tomographic imaging the dynamic properties of a medium. Such detectors include for example, but are not limited to, photo-diodes, PIN diodes (PIN), Avalanche Photodiodes (APD), charge couple device (CCD), charge inductive device (CID), photo-multiplier tubes (PMT), multi-channel plate (MCP),acoustic transducers and the like.
The present invention builds upon previous disclosures in U.S. Pat. Nos. 5,137,355 ("the '355 patent") entitled "Method of Imaging a Random Medium" ("the '355 patent") and U.S. Pat. No. 6,081,322 ("the '322 patent") entitled "NIR Clinical Opti-Scan System", the disclosures of both the '355 and '322 patents are incorporated herein by reference. Disclosed in these patents is an approach to optical tomography, and the instrumentation required to accomplish the tomography. The modifications in the present invention provide fast data acquisition, and new imaging head designs. Fast data acquisition allows accurate sampling of dynamic features. The modification in the imaging head allows accommodation of different size targets (e.g., breast); the stabilization of the target against motion artifacts; conforming the target to a simple well-defined geometry; and knowledge of source and detector positioning on or about the target. All of the enumerated features listed above for the imaging head is crucial for accurate image reconstruction.
Additionally, the present invention uses detector circuitry that allows quick adaptation of the measurement range to the signal strength thereby increasing the over-all dynamic range. "Dynamic range" for the purposes of this description means the ratio between the highest and lowest detectable signal. This makes the circuitry suitable for use with source-detector distances that can vary significantly during the data collection, thereby allowing fast data acquisition over wide viewing angles. For instance, we are aware that dynamic features of dense scattering media may be extractable from measurements using a single source and single detector at a fixed distance between each other. Depending on the implementation, such an arrangement could be made using a detector of relatively small dynamic range. Although we are aware of the possible usefulness of such a measurement, our invention allows the measurement of dynamics in optical properties of dense scattering media using source-detector pairs over a wide range of distances (e.g., greater than or about 5 cm). Such fall tomographic measurements allow for improved accuracy in image reconstruction.
Depending upon the implementation, it is within the scope of the present invention to include those embodiments using a restricted source detector distance and therefore not requiring fast gain adjustment. For example, in one embodiment, the system of the present invention can also be operated using detector channels of low-dynamic range (e.g., 1:10.00) when detector fibers of a fixed distance from the source are being used for the measurement (e.g., the detector opposite the source).
The data collection scheme of the present invention disclosed herein provides time-series of raw data sets that provide useful information about dynamic properties of the scattering medium without any further image reconstruction. For example, by displaying the raw data in a color mapping format, features can be extracted by sole visual inspection. In addition to that, analysis algorithms of various types such as, but not limited to, linear and non-linear time-series analysis or pattern recognition methods can be applied to the series of raw data. The advantage of using these analytical methods is the improved capability to reveal dynamic signatures in the signals.
In another implementation, image reconstruction methods may be applied to the sets of raw data thereby providing time series of cross-sectional images of the scattering medium. For these implementations, analysis methods of various types such as, but not limited to, linear and non-linear time-series analysis, filtering, or pattern recognition methods can be applied. The advantage of using such analysis is the improved extraction of dynamic features and cross-sectional view, thereby increasing diagnostic sensitivity and specificity. These methods are explained in detail in the '355 and '322 patents, which were previously described and incorporated in as reference.
The invention reveals measurements of real-time spatiotemporal dynamics. Depending on the implementation, an image of dynamic optical properties of scattering medium such as, but not limited to, the vasculature of the human body in a cross-sectional view is provided. The technology employs low cost, compact instrumentation that uses non-damaging near infrared optical sources and features several alternate imaging heads to permit investigation of a broad range of anatomical sites.
In another implementation, the principles of the present invention can be used in conjunction with contrast agents such as absorbing and fluorescent agents. In another variant, the present invention allows tie cross-sectional measurements of changes in optical properties due to variations in temperature. The advantage of this variant is seen, but not restricted to, the use of monitoring cryosurgery.
A system using the modified instrumentation and described methods of the instant invention is capable of producing cross-sectional images of real-time events associated with vascular reactivity in a variety of tissue structures (e.g., limbs, breast, head and neck). Such measurements permit an in-depth analysis of local hemodynamic states that can be influenced by a variety of physiological manipulations, pharmacological agents or pathological conditions. Measurable physiological parameters include identification of local dynamic variations in tissue blood volume, blood oxygenation, estimates of flow rates, and tissue oxygen consumption. It is specifically noted that measurements of several locations on the same medium can be taken. For example, measurements may be taken of the leg and arm areas of a patient at the same time. Correlation of data between the different locations is available using the methods described herein.
The invention also provides both linear and non-linear time series analysis to reveal site specific functionality of the various components of the vascular tree. Thus the response characteristics of the major veins, arteries and structures associated with the microcirculation can be evaluated in response to a range of stimuli.
Fast data collection methods are particularly helpful because there are many disease states with specific influences on the spatial-dynamic properties of vascular responses. Accordingly, it is understood that significantly greater contrast mechanisms are definable, with much greater diagnostic sensitivity. This is accomplished by collecting and evaluating data in the time domain. These results are not available by performing static imaging studies.
The importance of dynamic properties follows directly from an understanding of the well known physiological reactivity of the vascular system. Control of the peripheral vasculature is mediated by neural, humoral and metabolic factors. Neural control is principally through autonomic activity. The details of these properties are well known to many, and can be found in any one of several medical physiology texts. Loss of autonomic control occurs in a variety of disease processes, especially in diabetes. Invariably, this loss of control will adversely influence local perfusion states. The current invention has the capacity to directly evaluate the concept known as vascular sufficiency. This tern takes into account the fact that, among its many roles, the vasculature is uniquely responsible for the delivery of essential nutrients to tissue, in particular, oxygen, and for the removal of metabolic waste products. Imbalances between supply and demand lead to relative hypoxic states, which often are clinically significant.
FIG. 1 illustrates one embodiment of the invention. Shown is a system 100 comprising medium 102. The medium can be any medium in which the propagation of the used source energy is strongly affected by scattering.
From a source module 101 energy is directed to the medium 102 from which the exiting energy is measured by means of detector 106, further discussed below. As previously discussed, there is a variety of sources, media, and detectors that may be used with the principles of the present invention. The following is a discussion of a sampling of such elements with the intention to describe how the invention is realized. In no way are these examples meant, nor do they intend to limit the invention to these implementations. A variation of elements as described herein may also utilize the principles of the present invention.
In one implementation, measurements of dynamics in the optical properties of the medium is accomplished by using optical source energy and performing rapid detection of the acoustic energy created by absorption processes in the medium. This can be implemented using both pulsed and harmonic modulated light sources, the latter allowing for lock-in detection. Detectors can be, but are not limited to, piezo-electric transducers such as PZT crystals or PVDF foils.
In another variant, a timing and control facility 104 is used to coordinate source and detector operation. This coordination is further described below. A device 116 provides acquisition and storage of the data measured by the detector 106. Depending on the implementation, control and timing of the system's components is provided by a computer, which includes a central processor unit (CPU), volatile and non-volatile memory, data input and output ports, data and program code storage on fixed and removable media and the like. Each main component is described in greater detail below.
FIG. 2 illustrates another implementation of a preferred embodiment of the present invention. Shown is a system and method that incorporates at least one wavelength measurement. Depending upon the implementation, this measurement is accomplished by alternately coupling light from diode lasers into transmitting fibers arranged in a circular geometry.
Referring again to FIG. 2, a system 200 includes an energy source, which in this implementation includes one or more laser 101. A reference detector 202 is used to monitor the actual output power of laser 101 and is coupled to a data acquisition unit 116. Such laser may be a laser diode in the NIR region. The laser is intensity modulated by a modulation means 203 for providing means of separation of background energy sources such as daylight. The modulation signal is also sent to a phase shifter 204 whose purpose is described further below. The light energy generated by the laser 101 is directed into an optical de-multiplexing device 300 further discussed in detail below. Using a rotating mirror 305, the light is directed into one of several optical source fiber bundles 306 that are used to deliver the optical energy to the medium 102. To provide good optical contact and measurement fidelity, one of several possible imaging heads 206 as described further below is used. A motor controller 201 is coupled to the de-multiplexing device 300 for controlling the motion of the rotating mirror 305. The motor controller 201 is also in communication with a timing control 104 for controlling the timing of the motion of mirror 305.
The measuring head 206 comprises the common end of a bifurcated optical fiber bundle, whose split ends are formed by the source fiber bundle 306 and detector fiber bundle 207. Source fiber bundle 306 and detector fiber bundle 207 form a bulls eye geometry at the common end with the source fiber bundle in the center. In other embodiments, source and detector bundles are arranged differently at the common end (e.g., reversed geometry or arbitrary arrangement of the bundle filaments). The common end of a bifurcated optical fiber bundle, preferably comes in contact with the medium, however, this embodiment is not limited to contact with the medium. For example, the common ends may simply be disposed about the medium. The signal is transmitted from the detector fiber bundle 207 to a detector unit 106 that comprises at least one detector channel 205 further described herein. The detector channel 205 is coupled to the data acquisition unit 116 and the timing control unit 104. Depending on the implementation, a phase shifter 204 may or may not be used, and is coupled to the detector unit 106 for the purposes of providing a reference signal for the purposes of filtering the signal received from bundle 207.
Depending on the implementation, illustrated in FIG. 3 is a device for the measurement of the dynamic properties of a scattering medium. This measurement is performed by sequentially reflecting light 302 off of a rotatable front surface mirror 306, mounted at a 45 degree angle to the incident source, into source fibers 306 arranged in a circular geometry about the rotating optic. The rotation is done by a motor 308 with a shaft 307 to which the mirror is attached. This embodiment has an advantage of enabling fast switching among the transmitting fibers. In particular, it provides the ability to introduce beam shaping optics between the reflective mirror and transmitting fibers thereby allowing fine adjustment of the illumination area available for coupling into the fibers. This is useful because it allows independent adjustment of the rotation speed of the reflective optic (i.e., switching speed), and the illumination time allowed for each transmitting fiber bundle. Thus, a range of illumination frequencies can be employed while allowing fine adjustment of the illumination time at each source position to permit collection of data having a suitable signal-to-noise ratio.
Light from laser 101 is transmitted to unit 300 by means of transmitting optics 303 including, but not limited to, fiber optics and free propagating beams. Further beam shaping optics 301 may be used to optimize in coupling efficiency into the transmitting fibers. Units 303 and 301 are under mechanical fine adjustment in their position with respect to the mirror 309.
Motor 308 is operated under control of motion control 201 to allow for precise positioning and timing. By this means, it is possible to operate the motor under complex motion protocols such as in a start-stop fashion where the motor stops at a desired location thereby allowing the stable coupling of light into a transmitting fiber bundle. After the measurement at this source location is performed, the motor moves on to the next transmitting fiber. Motion control is in two-way communication with the timing control 104 thereby allowing precise timing of this procedure. Motion control allows the assignment of relative and/or absolute mirror positions allowing for precise alignment of the mirror with respect to the physical location of the fiber bundle. The mirror 306 is surrounded by a cylindrical shroud 309 in order to shield off stray light to prevent cross-talk. The shroud comprises an aperture 310 through which the light beam 302 passes toward the transmitting fiber. It is recognized and incorporated herein other schemes which may be used,(e.g., use of a fiber-optic switching device) to sequentially couple light into the transmitting fibers.
In an equivalent embodiment, fast switching of source positions is accomplished by using a number of light sources, each coupled into one of the transmitting fibers 306 which can be turned on and of each independently by electronic means.
The device employs the servo-motor control system 308 in FIG. 3 with beam steering optics, described above, to sequentially direct optical energy emerging from the source optics onto about 1 mm diameter optical fiber bundles 306, which are mounted in a circular array in the multiplexing input coupler 300. The transmitting optical fiber bundles 306, which are typically 2-3 meters in length are arranged in the form of an umbilical and terminate in the imaging head 206.
Depending on the implementation, the apparatus of the present invention required for time-series imaging, employs the value of using a geometrically adaptive measurement head or imaging head. The imaging head of the present invention provides features that include, but are not limited to, 1) accommodating different size targets (e.g., breast); 2) stabilizing the target against motion artifacts; 3) conforming the target to well-defined geometry; and 4) to provide exact knowledge of locations for sources and detectors. Stability and a known geometry both contribute to the use of efficient numerical analysis schemes.
There are several different embodiments of the imaging head for data collection that may utilize the principles of the present invention. For example the use of an iris imaging head previously disclosed in the '322 and '355 patents , which are incorporated by reference in this disclosure, may be used with the principles of the present invention.
Described below are two exemplary imaging heads with the understanding that the invention may or may not use any type of imaging head, and if an imaging head is used, it would provide the features previously described.
As illustrated in FIG. 4, the iris unit can be employed as a parallel array of irises 402, 404, 406 enabling volume imaging studies. FIG. 4 illustrates how this can be configured for studying a medium 410, in this example a human breast, using an imaging head 408. As described previously, the medium used in the present invention can be any medium, which allows scattering of energy.
In one implementation, the imaging head illustrated in FIG. 5 is a flexible pad configuration. This planar imaging unit functions as a deformable array and is well suited to investigate body structures too large to permit transmission measurements (e.g., head and neck, torso, and the like). Using this type of imaging head, optical measurements are made in a back-reflection mode. Optical fiber bundles 502 originating from the optical multiplexing input coupler 112 (described elsewhere) terminate at the deformable array or flexible pad 500. The pad can be made of any flexible material such as black rubber or the like. The optical fiber bundles may be bifurcated and have ends 504 that both transmit and receive light. More than one pad may or may not be used, although an additional pad is not necessary for the purpose of the present invention, or for measurement application to other portions of the medium or to the same medium. For example, in the case of a breast exam, both pads maybe applied to the same breast having one pad above and one pad below the breast. In addition, one pad maybe applied to the right breast by having the pad deformed around the breast. Similarly, the other pad may be applied to the left breast. This configuration would allow both breasts to be examined at the same time. In addition, information may be correlation between the data collected from the two different members of the body. Again, the invention can be applied to other media and is not limited to portions of the human body. Thus, correlation between different media may be collected using this technique.
As further shown in FIG. 5, the additional pad would have similar functions as the pad previously described and would have optical fiber bundles 503, flexible pad 505, and bifurcated optical fiber bundle ends 501 similar to the previous pad described. The array itself can be deformed to conform to the surface of a curved medium to be imaged (e.g. portion of the torso). The deformable array optical energy source and receiver design includes, depending on the implementation, a 7æ9 array (63 total bundles) of optical fiber bundles as illustrated in FIG. 6. In one variant, each bundle is typically 3 mm in diameter. Depending on the implementation, eighteen (18) of the sixty-three (63) fiber bundles may be arranged in an array to serve as both optical energy sources or energy transmitters, and receivers to sequentially deliver light to a designated target and receive emerging optical energy. In this implementation, the remaining forty-five (45) fiber bundles act only as receivers of the emerging optical energy.
The geometry of the illumination array is not arbitrary. The design shown in FIG. 6 as an exemplary illustration has been configured, as have other implementations, to minimize the subsequent numerical effort required for data analysis while maximizing the source-density covered by the array. The fiber bundles are arranged in an alternating pattern as described by FIG. 6 and shown here with the symbols "X" and "0". In one implementation, a pattern of 00X000X00, X000X000X can be used on the imaging head. 'X' denotes a source/receiver fiber bundle, and '0' is a receiver only. FIG. 6 indicates 2D imaging planes formed by multiple source/detector positions along a line that can be used with this particular pattern. The labels refer to the numbers of sources/detectors found along those lines of optical fiber ends on the pad using the following nomenclature: "S" followed by a number indicates the number of source positions along that line; "D" followed by a number indicates the number of detection points along that line. For instance; "S3-D3" indicates an imaging plane formed by three source positions and three detection points. Basically, the design allows for the independent solution of two dimensional (2-D) image recovery problems from an eighteen (18) point source measurement. As a result, a composite three dimensional (3-D) image can be computed from superposition of the array of 2-D images oriented perpendicular to the target surface. Another advantage of this geometry is that it readily permits the use of parallel computational strategies without having to consider the entire volume under examination.
The advantage of this geometry is that each reconstruction data set is derived from a single linear array of source-detector fibers, thereby enabling solution of a 2-D problem without imposing undue physical approximations. The number of source-detector fibers belonging to an array can be varied. Scan speeds attainable with the 2-D array illustrated in FIG. 6 are the same as for other imaging heads with 2-D arrays since the scan speed depends only on the properties of the input coupler. Thus, faster scan speed are available for the creation of a 3-D image.
In another implementation, illustrated in FIG. 7, is an imaging head based on a "Hoberman" sphere geometry. In a Hoberman structure, the geometry is based on the intersection of a cube and an octahedron, which makes a folding polyhedron called a trapezoidal icosatetrahedron. This structure has been modified and implemented in a form of an imaging head of a hemispherical geometry. For many purposes of the instant invention, it is appropriate to use design features of smoothly varying surfaces based on the Hoberman concept of expanding structures. Depending on the implementation, other polygonal or spherical-type shapes may also be used with the principles of the present invention for other imaging head designs. Adjustment of the device in FIG. 7 causes uniform expansion or contraction, thereby always preserving a hemispherical geometry. Imaging head 700 illustrates one example of modification to the "Hoberman" geometry. A receptacle for the fiber bundles 701 is disposed about imaging head 700. Target volume 702 is where the medium would enter the imaging head in this implementation. This geometry is well suited for the investigation of certain tissues such as the female breast or the head. Depending on the implementation, attachment of optical fibers to the vertices of the hemisphere allows for up a seventeen (17) source by seventeen (17) detector measurement. The folding structure can be extended to accommodate a more "tear drop" or "bullet" shape of the target medium by attaching additional circular iris-like structures on top that expand and contract with the hemisphere. FIG. 7 shows the combination of the hemisphere with one top iris comprising receptacles for 8 additional fiber bundles leading to an overall number of 25 source by 25 detector positions at the main vertices for this configuration. More than one iris can be attached to the top of the hemisphere. The diameter of the additional top irises may or may not differ from the hemisphere diameter. The detectors or energy receivers may be disposed about the imaging head and the detectors are located on the inner aspect of the expanding imaging head. Additional fiber bundles can be attached to the interlocking joints, permitting up to a 49 source by 49 detector measurement for the hemisphere only and up to 16 source/detector positions per added iris.
Depending on the implementation, light collected from the target medium is measured by using any of a number of optical detection schemes. One embodiment uses a fiber-taper, which is bonded to a charged coupled detector (CCD) array. The front end of the fiber taper serves to receive light exiting from the collection fibers. These fibers are preferably optical fibers, but can be any means that allows the transmission and reception of signals. The back end of the fiber taper is bonded to a 2-D charge-coupled-detector (CCD) array. In practice, use of this approach generally will require an additional signal attenuation module.
An alternate detection scheme employs an array of discrete photo detectors, one for each fiber bundle. This unit can be operated in a phase lock mode thereby allowing for improved rejection of ambient light signals and the discrimination of multiple simultaneously operated energy sources.
In another embodiment, in order to fulfill the demands posed by the desired physiological studies on the instrument, the following features characterize the detector system: scalable multi-channel design (up to 32 detector channels per unit); high detection sensitivity (below 10 pW); large dynamic range (1:106 minimum); multi-wavelength operation; ambient light immunity; and fast data acquisition (order of 100 Hz all-channel simultaneous capture rate).
To achieve this, the detector system uses photodiodes and a signal recovering technique involving electronic gain switching and phase sensitive detection (lock-in amplification) for each detector fiber (in the following referred to as detection or detector channels) to ensure a large dynamic range at the desired data acquisition rate. The phase sensitive signal recovery scheme not only suppresses electronic noise to a desired level but also eliminates disturbances given by background light and allows simultaneous use of more than one energy source. Separation of signals from simultaneously operating sources can be achieved, as long as the different signals are encoded in sufficiently separated modulation frequencies. Since noise reduction techniques are based on the reduction of detection bandwidth, the system is designed to maintain the desired rate of measurements. In order to achieve a timing scheme that allows simultaneous readout of the channels, a sample-and-hold circuit (S/H) is used for each detection channel output. The analog signals provided by the detector channels are sampled, digitized and stored using the data acquisition system 116. One aspect is the flexibility and scalability of the detection instrument. Not only are the detector channels organized in single, identical modules, but also the phase detection stages, each containing two lock-in amplifiers, are added as cards. In this way, an existing setup can easily be upgraded in either the number of detector channels and/or the number of wavelengths used (up to four) by cloning parts of the existing hardware.
FIG. 8 shows the block diagram of one implementation of a detector channel. In this implementation, two energy sources are used. After detecting the light at the optical input 801 by a photo detector 802 the signal is fed to a transimpedance amplifier 803. The transimpedance value of 803 is externally settable by means of digital signals 813 (PTA=Programmable Transimpedance Amplifier). This allows the adaptation to various signal levels thereby increasing the dynamic range of the detector channel. The signal is subsequently amplified by a Programmable Gain Amplifier (PGA} whose gain can be set externally by means of digital signals 814. This allows for additional gain for the lowest signal levels (e. g., in one implementation pW-nW) thereby increasing the dynamic range of the detector channel.
In one embodiment, at least one energy source is used and the signal is sent to at least one of lock-in amplifiers (LIA) 805, 809. Each lock-in amplifier comprises an input 808,812 for the reference signal generated by phase shifter 204 from FIG. 2. After lock-in detection, the demodulated signal is appropriately boosted in gain by means of a programmable gain amplifier (PGA) 806, 810 in order to maximize noise immunity during further signal transmission and to improve digital resolution when being digitized. The gain of PGA 806, 810 is set by digital signals 815.
At each output, a sample-and-hold circuit (S/H) 807, 811 is used for freezing the signal under digital timing by means of signal 816 for purposes described herein.
In one embodiment, the signal 815 is sent to PGA 806,810 in parallel. In one embodiment, the signal 816 is sent to 807,811 in parallel.
As previously illustrated in FIG. 1, the analog signal provided by each of the channel outputs is sampled by a data acquisition system 116. In one embodiment, PC extension boards might be used for this purpose. PC extension boards also provide the digital outputs that control the timing of functions such as gain settings and sample-and-hold.
As previously noted, timing is crucial in order to provide the desired image capture rate and to avoid false readings due to detector-to-detector time skew. FIG. 9 shows one improvement of the invention over other timing schemes. With systems not comprising fast adaptable gain settings (such as some CCD based systems), a schedule according to 905 has to be implemented. The implementation in FIG. 9 illustrates one use of a silicon photo-diode in process 904, which can be replaced by various detectors previously mentioned. A time series of data is acquired for a fixed source position. After finishing this task, the source is moved 902 with respect to the target 901 and another series of data is collected. Measurements are performed in this fashion for all source positions. Every image 903 of the resulting time series of reconstructed images is reconstructed from data sets merged together from the data for each source position. This schedule does not allow real-time capture of all physiologic processes in the medium and therefore only applies to certain modes of investigation. Although we are aware of the use of such schemes, e.g., when monitoring responses on repeatable maneuvers, the timing scheme for the invention very much improves on this situation.
Because the invention allows for fast source switching and large dynamic range and high data acquisition rates, a schedule indicated by 904 is performed. Here, the source position is switched fast compared to the dynamic features of interest and instantaneous multi-channel detection is performed at each source position. Images 903 are then reconstructed from data sets, which represent an instant state of the dynamic properties of the medium. Only one time series of full data sets (i. e., all source positions and all detector positions) is being recorded. Real time measurement of fast dynamics (e. g., faster than I Hz) of the medium is provided by the invention.
FIG. 10 shows one embodiment of a detailed schedule and sequence of the system tasks 1001 involved in collecting data at a source position and the proceeding of this process in time 1002. Task 1003 is the setting of the optical de-multiplexer to a destined source position and setting the detectors to the appropriate gain- settings. The source position is illuminated for a period of time 1004, during which the lock-in amplifiers settle 1005. After the time it takes the S/H to sample the signal 1006, the signal is held for a period of time 1007, during which all channels are read out by the data acquisition. It is worthwhile noticing that during reading out the S/H, other tasks, like moving the optical source, setting the detector gains for the new source position, and settling of the lock-in, are being scheduled. This increases greatly the achievable data acquisition rate of the instrument.
This concept of a modular system is further illustrated in FIG. 11. Up to thirty-two (32) detector modules 1100 (each with 2 lock-in modules each for two modulation frequencies) are arranged using an enclosure 1102. The cabinet also can carry up to two phase shifting modules 1104, 1106, each containing two digital phase shifter under computer control. The ability to adjust the reference phase with respect to the signal becomes necessary since unavoidable phase shifts in the signal may lead to non-optimum lock-in detection or can even result in a vanishing output signal. Organization of data, power supply and signal lines is provided by means of two back planes 1108, 1110
Depending on the implementation, the detector system design illustrated in FIG. 8 allows one cabinet to operate at a capacity of 32 detectors with four different sources requiring 128 analog to digital circuit (ADC)-board input channels. The upper 1108 and the lower 1110 back plane are of identical layout and have to be linked in order to provide the appropriate distribution of supply-, control- and signal voltages. This is achieved using a 6U-module fitting both planes from the backside, that provides the necessary electric linking paths, and interfaces for control- and signal lines.
FIG. 12 shows the schematic of one implementation of a channel module. In this implementation, a silicon photodiode 1206 is used as the photo-detector. A Programmable Transimpedance Amplifier (PTA) 1201 is formed by an operational amplifier 1204, resistors 1201 and 1202 and an electronic switch 1205, the latter of which is realized using a miniature relay. Other forms of electronic switches such as analog switches might be used. Relay 1205 is used to connect or disconnect 1203 from the circuit thereby changing the transimpedance value of 1201. A high-pass filter (R2, C5) is used to AC-couple the subsequent programmable gain instrumentation amplifier IC2 (Burr Brown PGA202) in order to remove DC offset. The board-to-board connectors for the two lock-in-modules are labeled as "slot A" 1210 and "slot B" 1212. The main connector to the backplane is a 96-pole DIN plug 1220.
FIG. 13, illustrates the electric circuit of the lock in modules 1210, 1212. The signal is subdivided and passed to two identical lock-in-amplifiers, each of which gets one particular reference signal according to the sources used in the experiment. The signal is first buffered IC1, IC7 (AD LF 111) and then demodulated using an AD630 double-balanced mixer IC2, IC8.
In order to remove undesired AC components, the demodulated signal passes through an active 4-pole Bessel-type filter IC3, IC4, IC9, IC10 (Burr Brown UAF42). A Bessel-type filter has been chosen in order to provide fastest settling of the lock-in amplifier for a given bandwidth. Since a Bessel-filter shows only slow stopband-transition, a 4-pole filter is being used to guarantee sufficient suppression of cross talk between signals generated by different sources (i.e. of different modulation frequency). The filter has its 3 dB point at 140 Hz, resulting in 6 ms settling time for a step response (<1% deviation of actual value). The isolation of frequencies separated by 1 kHz is 54 dB. The filters are followed by a programmable gain amplifier IC5, IC 11, whose general function has been described above. The last stage is formed by a sample-and-hold chip (S/H) IC6, IC12 (National LF398).
In another implementation, the phase sensitive detection can be achieved with digital methods using digital signal processing (DSP) components and algorithms. The advantage of using DSP with the principles of the present invention is improved electronic performance and enhanced system flexibility.
In another implementation, an analog-to-digital converter is used for each detector channel thereby improving noise immunity of the signals.
Although illustrative embodiments have been described herein in detail, those skilled in the art will appreciate that variations may be made without departing from the spirit and scope of this invention. Moreover, unless otherwise specifically stated, the terms and expressions used herein are terms of description and not terms of limitation, and are not intended to exclude any equivalents of the system and methods set forth in the following claims.
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text:
Who buried dead dog on Robinswood Hill?
Posted: March 22, 2014|
A dead dog has been found half-buried at Robinswood Hill Country Park in Gloucester.
Dog walker June Koppe made the gruesome find and fears it could have been the victim of a fighting ring.
She got in touch with the Citizen in a bid to try and shed some light on the animal's fate.
June said: "I am a frequent dog walker on Robinswood Hill which is usually a pleasurable experience.
"However a few days ago whilst up there I noticed that my youngest dog had run off the main path and was sniffing and picking at what looked liked some sacking.
"I went to see what was so interesting to him to find a half buried, in sacking, dead dog. The look on the dog's face was pretty gruesome as his eyes were staring and teeth bared which indicated to me that the dog had not had a peaceful death.
"At first I thought maybe someone had buried their beloved pet there although I did find this to be a very strange thing to do. Anyway I then carried on with my walk, found the rangers and reported my find to them.
"They also thought it strange as they said the scattering of pet's ashes is a common occurrence but they have never come across anyone actually burying a dog up there.
"Once I arrived home I did report this to the Police on the 101 number and also e-mailed the rangers to find out what had happened once they had found the dog.
"The head ranger replied and said that they had in been in contact with Environmental Health who told them to bury the dog which they did. At this point I was concerned as had hoped someone would have had a look at the dog to see if it had any injuries or was micro-chipped as I was beginning to wonder whether this poor dog had been used in dog fighting or something equally horrific and could possibly be someone's stolen pet.
"I also then remembered about a week ago whilst on the hill my dog came out from behind a tree with what I thought was the leg of a rabbit in his mouth which he then dropped but am now wondering whether it was a rabbit or not."
June said she wondered if the dog's death was linked to fighting.
Do you have any information? Contact the Citizen on 01452 698821 or police on 101.


text:
Search the collections
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Negative - Sea Lake, Victoria, 1920 Reg. No: MM 002181
- Description Of Content:
- Best Street in Sea Lake with motor cars and pedestrians. There is a silo and a water tank in the background. There are light poles on the left and telephones on the right.
- Acquisition Information:
- Copied from Mr William (Bill) Boyd, 1985
- Acknowledgement:
- The Biggest Family Album of Australia, Museum Victoria
More information
|Tagged with:
|motor cars, telegraph infrastructure, telegraph poles, water tanks, water towers
|Themes this item is part of:
|Images & Image Making Collection, Information & Communication Collection, Transport Collection, Bill Boyd Photographic Collection, The Biggest Family Album in Australia Collection
|Primary Classification:
|Secondary Classification:
|Tertiary Classification:
|Negative: Black & White; 35 mm
|Place & Date Depicted:
|Sea Lake, Mallee, Victoria, Australia, 1920
|Mr William (Bill) Boyd, 1920
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text:
Today's Haaretz Magazine profile of Palestinian filmmaker Rima Essa and her new documentary on a Palestinian child with leukemia raises important questions. Essa (and presumably her film) complains mainly about Israel. But she also has harsh words for Palestinian hospitals.
"'At [Israeli hospital] Hadassah Ein Karem the oncology ward looks very nice and well kept; there's a playroom and toys and someone who devotes their time to the sick children. … At the hospitals in the territories you don't find conditions like that. At [West Bank hospital] Al-Hussein, I saw a nicely painted playroom with Lego and puzzles, but it was open only two hours a day because there was no budget and no volunteers.
'The people who live in the territories don't have the same kind of awareness. Maybe because they themselves live in difficult conditions; maybe it's a cultural thing. I saw Ahlam's mother pleading with neighbors and people from the area to donate blood for her daughter. There's no awareness in our society about things like donating blood, or organ donations'. …
[Essa] documented Al-Hussein's use of drugs from Israel that were past their expiration date. In one of the film's toughest scenes, the medical staff knows that two injections of a certain drug are needed, but the department only has enough for one. The staff decides to divide the one dose they have between Ahlam and another little girl. …"
Clearly, the Palestinian Authority can't fund its hospitals as Israel does (though it could stop buying expired drugs): It's a young, struggling state-in-the-making, while Israel is a 62-year-old, comparatively wealthy state. But Israel had relatively good hospitals even when it, too, was a young, struggling state-to-be, thanks to the generosity of overseas Jews, who built, equipped, and staffed them. Hadassah Hospital, for instance, was founded by the American Hadassah organization, which built six hospitals in Israel before the state's establishment. Even today, donations from overseas Jews contribute greatly to Israel's cutting-edge medicine.
Like the Jews, Palestinians have a large Diaspora. Also like the Jews, parts of that Diaspora are well-educated and well-off, with estimated assets of $40-80 billion.
But there the similarity ends — because overseas Palestinians evidently have no interest in doing for the PA what overseas Jews did for pre-state Israel. If they did, their hospitals wouldn't look as Essa described.
Moreover, Israel is the world's only Jewish state. But there are 22 Arab states and 56 Muslim states, many of them among the richest in the world. Had they any interest in helping their Palestinian brethren, they could easily build hospitals rivaling anything in Israel. But they don't.
Finally, there are the international-aid organizations that claim to care so deeply about the Palestinians, like Turkey's IHH, which sponsored May's flotilla to Gaza. But it turns out most of the medicines they donate are expired and must be tossed: According to Gaza's Health Ministry, only 30 percent of donated medical aid is actually usable.
With friends like these, Palestinians don't need enemies. But that's precisely why, 17 years after the PA's establishment, they still need Israel so much.


text:
Gran Turismo 5
Minimal Car Buying Guide by blowseph
Version: 1.4 | Updated: 02/20/11 | Printable Version
============================================================================== ------------------------------- GRAN TURISMO 5 ------------------------------- ----------- CLEARING ALL ASPEC & BSPEC RACES WITH MINIMAL CAR BUYS ----------- ---------------------------- WRITTEN BY: BLOWSEPH ---------------------------- ============================================================================== With all of the races in this game and all of the different restrictions those races have, sometimes it can be hard to know what car to use on what race or where to get a car to use on a certain race. This guide is intended to provide you with a "map" to get you through all of GT5's Aspec and Bspec races while buying as few cars as possible, and to help you find a car to use any given race if you're stumped about what to do next. ------------------------------------------------------------------------------ A FEW NOTES: If you level up and a new race opens up to you that you do not have a car for, that doesn't mean you have to go and buy a car to do that race right then and there. If you skip over the races you do not have cars for, somewhere down the road you will almost always come across a new prize car that you can use in the races you have skipped over. The cars I have listed to use are only suggestions. At times there may be different cars you come across that you could use other than what I have noted, which is OK. There's more than one way to get from point A to point B. Before starting the races, go do the license tests. These will not only give you some much needed exp/levels right off the start, but will also give you a few nice prize cars to use before you've even done any races. For some people license tests are hard, and getting anything more than a bronze may be out of the question. For this reason, I have not included any prize cars awarded by license tests over what you can get at the bronze level. Some of these cars require tuning (in some cases extensively) to be able to win. But they can still win. You will at some point find that there are no more open races at your level that you have a car for. You will need to re-visit races you've already won to gain more exp and level up to open new events and gain new prize cars. ------------------------------------------------------------------------------ To do ALL the Aspec & Bspec races, you only NEED to buy 4 (or possibly 5) cars 1 - Any Mini Cooper (do not buy the Mini Cooper 1.3i '98, you win it later) 2 - Any Ferrari (do not buy the F40 or the California, you win them later) 3 - Lamborghini Gallardo 4 - Formula GT 5 - Any NASCAR** (unless you can gold all three of the NASCAR special events) ------------------------------------------------------------------------------ The following chart will be laid out in this format: EVENT - CAR TO USE (WHERE TO WIN CAR) Races you will have to buy a car for will be preceded by ** ------------------------------------------------------------------------------ ----------BEGINNER------------------------------------------------------------ ------------------------------------------------------------------------------ Sunday Cup - Any car - pretty much any starter car you pick will win this FF Challenge - Nissan MM-R cup car (A license bronze) World Compact Cup - DN-X Concept '02 (IC license bronze) Light Weight K Cup - Honda Z Act '70 (Aspec japanese classic) Japanese Classic - Dome DOME-ZERO Concept '78 (Aspec supercar nostalgia) Vitz Race - Yaris or Vitz (Aspec/Bspec sunday cup) European Classic - Autobianchi A112 Abarth '79 (Bspec world compact cup) World Classic Car - Alfa Romeo Giulia Sprint GTA '65 (Aspec italian cup) FR Challenge - Mazda Eunos J-Limited (NA) '91 (IB license test bronze) ------------------------------------------------------------------------------ ----------AMATEUR------------------------------------------------------------- ------------------------------------------------------------------------------ Clubman Cup - Any car European Hot Hatch - Hommell Berlinette '99 (Aspec world compact car) NR-A Roadster Cup - Mazda Eunos J-Limited (NA) '91 (IB license test bronze) Sport Truck Race - Dodge RAM (IA license test bronze) Japanese 90's - Mazda Eunos J-Limited (NA) '91 (IB license test bronze) French cup- Bugatti Veyron 16.4 '09 (Aspec gran turismo world championship) Italian cup- Maserati GranTurismo S '08 (Aspec supercar festival) Classic Muscle Car Championship - car from bronzing all NASCAR special events Supercar Nostalgia - Lamborghini Countach '74 (Bspec Lamborghini Cup) ------------------------------------------------------------------------------ ----------PROFESSIONAL-------------------------------------------------------- ------------------------------------------------------------------------------ **Mini Challenge - Buy any Mini Cooper except for Mini Cooper 1.3i '98 Muscle Car Champ. - Buick Special '62 (Aspec classic muscle car championship) Super Car Festival - Mazda Furai (Bspec NR-A roadster cup) Lupo Cup - Lupo cup car (Aspec or Bspec european hot hatch championship) Sports Car Cup 80's Festival - Honda Civic Si Race '87 (Aspec clubman cup) **Lamborghini Exclusive - Buy a Gallardo (need for 1-make Gallardo race later) British Lightweights (Aspec) - Marcos Mini GT '70 (Bspec mini challenge) British Lightweights (Bspec) - Triumph Spitfire (Aspec british lightweights) **La Festa Cavallino - Buy any Ferrari except F40 or California Gran Turismo World Championship - Mazda Furai (Bspec NR-A roadster cup) ------------------------------------------------------------------------------ ----------EXPERT-------------------------------------------------------------- ------------------------------------------------------------------------------ Tuning Car Grand Prix - Mazda Furai (Bspec NR-A roadster cup) Schwarzwald League A - Lupo cup car (Aspec or Bspec european hot hatch champ.) MR Sports Cup - Pagani Zonda R (Bspec gran turismo world championship) Historic Racing Car Cup - Toyota 7 Race Car (Bspec like the wind) Race of Turbo Sports - Mazda Furai (Bspec NR-A roadster cup) Gallardo Trophy - use the Gallardo you bought for the Lamborghini race Japan Championship - MINOLTA Toyota 88C-V (Aspec like the wind) Gran Turismo All Stars - MINOLTA Toyota 88C-V (Aspec like the wind) Polyphony Digital Cup - MINOLTA Toyota 88C-V (Aspec like the wind) ------------------------------------------------------------------------------ ----------EXTREME------------------------------------------------------------- ------------------------------------------------------------------------------ Schwarzwald League B - Opel Speedster/Turbo (Bspec/Aspec schwarzwald League A) Like The Wind (Aspec) - Pagani Zonda R (Bspec gran turismo world championship) Like The Wind (Bspec) - MINOLTA Toyota 88C-V (Aspec like the wind) **NASCAR Series - Get gold on all NASCAR special events, or buy a NASCAR European Championship - Pagani Zonda R (Bspec gran turismo world championship) German Touring Car - Audi R8 or Lexus IS F(Aspec/Bspec nurburgring 4h endur.) Super GT - MINOLTA Toyota 88C-V (Aspec like the wind) American Championship - Cobra 427 '66 (Bspec classic muscle car championship) **Formula GT - Buy a Formula GT Dream Car Championship - MINOLTA Toyota 88C-V (Aspec like the wind) ------------------------------------------------------------------------------ ----------ENDURANCE----------------------------------------------------------- ------------------------------------------------------------------------------ Grand Valley 300km - Any car Roadster 4 hours - Mazda Eunos J-Limited (NA) '91 (IB license test bronze) Laguna Seca 200 miles - Any car Indianapolis 500 miles - Any car Suzuka 1000km - Any car Nurburgring 4h - Any car Tsukuba 9h - Any car Le Mans 24h - Any car Nurburgring 24h - Any car ------------------------------------------------------------------------------ Resources used: http://www.mygranturismo.net/carlist.php http://www.mygranturismo.net/eventlist.php If you see any problems or anything, you can add me on PSN (JohnSmallberries) and send me a message to let me know. ------------------------------------------------------------------------------ Have run racing!


text:
In a test system, a silicon interconnect is provided that can accommodate a packaged part, such as a Land Grid Array (LGA) package. The interconnect can be made by etching a silicon substrate to form projections therefrom; forming an insulation or passivation layer through deposition or growth; depositing a seed layer over the insulation layer; depositing a metal layer over the seed layer; and etching contact members from the seed and metal layers using a single mask step. In a preferred embodiment, the metal layer is coated with another metal layer that matches the metal of the packaged part's electrical communication nodes. In one embodiment, the contact surfaces of the silicon contact are plated in gold and are planar. Included within the scope of the current invention are at least one method of testing an LGA package and at least one method of allowing electrical communication with a packaged part.
1. A test system comprising:
a carrier electrically configured to hold at least one die, said at least one die having at least one bond pad thereon having a non-metal silicide metal surface;
a test head configured to electrically communicate with said carrier;
an interconnect mounted to one of said carrier and said test head, said interconnect having at least one projection for contacting said non-metal silicide metal surface of said at least one bond pad of said at least one die, said at least one projection having a metal surface comprising a same non-metal silicide metal as said non-metal silicide metal surface of said at least one bond pad of said at least one die; and
testing equipment coupled to said test head.
2. The test system in
3. The test system in
4. The test system in
5. The test system in
6. A test assembly, comprising:
a socket;
a packaged part within said socket, wherein said packaged part has at least one packaged part electrical contact with a surface made of a non-metal silicide metal; and
a silicon insert within said socket, said silicon insert having at least one insert electrical contact touching one of said at least one packaged part electrical contact, said at least one insert electrical contact having a surface made of the same non-metal silicide metal of said surface of said at least one packaged part electrical contact of said packaged part.
7. The test assembly in
8. The test assembly in
9. The test assembly in
10. The test assembly in
11. The test assembly in
This application is a divisional of application Ser. No. 09/387,987, filed Sep. 1, 1999, now U.S. Pat. No. 6,556,030, issued Apr. 29, 2003.
1. Technical Field
The present invention relates generally to a device and method for providing electrical communication with a packaged integrated circuit device. More specifically, the present invention concerns a silicon interconnect and a method for fabricating a silicon interconnect for a Land Grid Array package.
2. State of the Art
In testing a semiconductor die, it is often useful to establish an electrical connection between the test equipment and the circuitry of a die. Testing may be performed on an unpackaged die that has been singulated from a semiconductor wafer, on a section of dice that is still part of the wafer, or on all of the dice on a wafer. In order to test a singular die, a partial wafer, or a full wafer, it may be beneficial to house the die structure in a temporary package such as a socket. The socket is configured to attach to a board which, in turn, is coupled to the test circuitry. One way to establish electrical communication between the die's bond pads and the socket is through the use of an interconnect. The interconnect is often made of silicon or some other etchable material, which may be coated with a conductive material to aid in electrical communication. The use of etchable materials such as silicon allows for the use of semiconductor fabrication techniques to form electrical contact members from a silicon substrate. Such techniques enable formation of electrical contact members at a pitch matching that of the die's bond pads. Silicon interconnects accommodate dice in other ways as well. For example, it is noteworthy that a die's bond pads are often made of aluminum. Given the temperatures associated with certain tests, it is important that the outermost coating of the interconnect be of some material other than aluminum; otherwise, the interconnect will permanently weld to the die during testing. Thus, it is taught in the art to coat a silicon interconnect with a material that is different from the material it will temporarily contact. Moreover, aluminum oxidizes relatively easily and, as a result, a die's aluminum bond pads are often covered with a thin film of nonconductive aluminum oxide. An interconnect must penetrate this oxide to reach the conductive aluminum of the bond pad in order to establish good electrical contact. To achieve this, it is taught to include fabrication steps that provide penetrating elements, such as blades, on the top of each interconnect contact. Steps that provide such elements are addressed in more detail in U.S. Pat. Nos. 5,326,428 and 5,419,807. These elements, while considered to be an improvement over flat contacts to a die's bond pads (see, for example, U.S. Pat. No. 5,607,818), necessarily cause damage to the bond pads and may shorten their useful life. Moreover, there is a risk that the elements will break off of the interconnect's contact.
These fabrication steps result in an interconnect that is configured to be inserted into the socket, receive a die's bond pads therein, and connect them to electrical terminals of the socket. Given the material of the interconnect and its placement in the package, such an interconnect is often referred to as a "silicon insert." The die is placed in the socket so that the die's bond pads are aligned with the interconnect's contact members; the socket is attached to the board; the board is coupled to the test circuitry; and testing commences.
After testing, the die may be removed from the socket. The interconnect may be removed as well, perhaps to be replaced by another interconnect having a different arrangement of contact members for another die. Dice that do not pass testing may be discarded, while those that do pass may undergo further processing, such as a burn-in process, and packaging.
Concerning the packaging of a die, there are varying degrees and types of packaging that a die may undergo. For example, a die may be configured as a "flip chip," wherein conductive material such as solder balls is attached directly to the bond pads or electrical traces formed in the surface of the die; the die is then "flipped," or mounted face down, so that the solder balls may connect with contact members of another device, such as a carrier substrate. Another example is a "chip scale package," which includes a die along with one or more minimal package elements, such as an encapsulating material in the form of a thin protective coating formed of glass or other materials. Such a coating may be bonded at least to the active surface of the die and edges thereof and sometimes to the sides and back side of the die as well. In addition, solder balls may be attached to electrical traces in the surface of the die or directly to the die's bond pads through openings in the encapsulating material in order to provide the aforementioned "flip chip" configuration. A Ball Grid Array (BGA) package serves as yet another example that involves even more packaging: the die is wire bonded to a substrate and encapsulated, and an array of solder balls on one side of the substrate is bonded to electrical traces leading through the substrate to the die. Alternatively, the package may comprise a Land Grid Array (LGA), which is similar to a BGA, except that flat contact pads—or lands—serve as external electrical communication nodes on the substrate instead of solder balls. Similarly, if an array of pins serves as the external electrical communication nodes for the package, such a package is known as a Pin Grid Array (PGA).
Other types of packages known in the art include dual in-line packages (DIP), wherein the leads extending from the package define two lines. Zigzag in-line packages (ZIP) have a line of leads, wherein every other lead extends into one of two planes (see U.S. Pat. No. 4,790,779). Leadless chip carrier (LCC) packages use sockets or conductive pads in place of leads and are configured to directly connect to a circuit board (see U.S. Pat. No. 5,375,320). Small outline packages (SOP) and thin small outline packages (TSOP) use a plastic ring around the package to contact the far end of the leads extending straight from two opposing edges of the package. The plastic ring can be removed after testing, and the leads may then be bent as needed. Quad flat pack (QFP) packages are similar to the SOPs in that a plastic ring surrounds the package and contacts the far end of the leads. In the QFP, however, the leads extend from four sides of the package (see also FIG. 6 of U.S. Pat. No. 5,903,443). Small outline j-bend (SOJ) packages use leads bent in a "j" shape, which allows for resiliency once the packages are attached to a circuit board.
As for testing these packaged dice, current methods of doing so also have problems. For example, testing LGA packages involves contacting the lands of the LGA with pins that have been stamped from a metal sheet. Each pin is placed within a hole that is one of an array of holes found within a plastic mold. This mold keeps an array of pins aligned with the package's array of lands. Test equipment may then access the lands through these pins. Unfortunately, there are several problems with using such pins. First, as the overall size of packages becomes smaller, the area of the lands decreases, as does the space between the lands. It is difficult for the stamped pins/plastic mold formation process to match the rate at which die packages are shrinking. In addition, using such pins often results in high inductance, thereby interfering with testing. Moreover, as with the silicon interconnects and the die bond pads, there exists the risk of a scrubbing action of the pins against the lands, which could damage both the pins and the lands.
Thus, there is a need in the art for improved testing structures and methods, including a need for improved temporary packaging for testing dice that have already undergone some degree of packaging. Included within this need is the desire to establish electrical communication between an interconnect and a related packaged die. Further, there is a more general need for improved electrical communication with a die, whether such communication is with a die as part of a permanently packaged part or a temporarily packaged part, or whether such communication is for test or non-test purposes.
Accordingly, the current invention provides an electrical connector and a method of forming it. Many exemplary embodiments of the current invention apply semiconductor fabrication techniques to an interconnect for a packaged part while reducing if not eliminating the problems attendant with prior silicon interconnects and prior interconnects for packaged parts. Such embodiments involve forming silicon interconnects having a contact surface that is complementary to the electrical contact surface of the packaged part to be tested. In some embodiments, such as those configured to contact LGA packages, the interconnect's contact surface is planar and parallel to the packaged part's contact surface. In more general embodiments, the interconnect's contacts are non-invasive or non-penetrating with respect to the electrical contacts of the packaged part. Some of these embodiments may be described as defining "male-female" configurations between the interconnect's contact surface and that of the packaged part.
An exemplary method of fabricating interconnects such as the ones described above involve defining a projection or protrusion from a substrate; providing a passivation/insulation layer over the substrate, including the projection; providing at least one seed layer over the passivation/insulation layer; providing at least one metal layer over the seed layer; and simultaneously patterning the metal layer and seed layer. In a preferred embodiment, the metal layer of the interconnect is the same metal as the packaged part's contact points.
A subsequent exemplary step within the scope of the current invention is illustrated in FIG. 2. That figure indicates that at least one seed layer 26 is deposited over the passivation/insulation layer 24. This seed layer 26 can be blanket deposited so that it conforms to the substrate 20 including its non-planar topography, thereby covering each projection 22, including the sidewalls and top thereof. This seed layer 26 provides nucleation sites for any subsequently deposited layer (in this exemplary embodiment, there will be a subsequently deposited metal layer). Moreover, this layer may also serve to help the subsequently deposited layer adhere to the in-process device as well as act as a barrier layer—preventing material from migrating from one side of the layer to the other. Exemplary materials for this seed layer 26 include tungsten, aluminum, copper, titanium nitride, and combinations thereof. General methods of depositing these seed layers are known in the art. For example, a tungsten layer may be sputtered onto the passivation/insulation layer 24 using a tungsten target and an argon source, and having a substrate temperature of about 250° C., an ambient temperature of about 200° C., and a low pressure, such as one ranging from 0.01 millitorr to 1×10−6 torr. Layers of the other materials may be sputtered under similar conditions with the appropriate target material. Sputtering titanium nitride may be accomplished using a titanium target and introducing nitrogen gas along with or after the argon source gas. As an exemplary range, this seed layer 26 can be 200 to 1000 angstroms thick.
As mentioned above and depicted in
A patterned mask layer is then provided over the metal layer 28. The metal layer 28 and seed layer 26 are etched according to the patterned mask, and the result appears in FIG. 4. Specifically, the contact members 30 are electrically isolated from one another. The etch also defines a conductive trace 32 and a connection pad 34 for at least one if not all of the contact members 30.
The conductive traces 32 and connection pads 34 are more easily distinguished in
One advantage of the method embodiment depicted in
Moreover, additional metal layers may be added without adding mask steps. Assuming that it is desirable to have a gold layer contact the packaged part being tested, it may not necessarily be desirable to have gold serving as the only layer over the seed layer. For instance, given the cost of gold, it may be preferable to deposit a different metal layer over the seed layer, wherein that layer serves as the main current-carrying layer, with a thinner plate of gold deposited thereover. In one such exemplary embodiment, the main current-carrying layer can be 500 angstroms to 4 microns thick, whereas the gold layer ranges from 200 angstroms to 1 micron in thickness. Further, a different metal layer may be able to adhere to the seed layer better than gold. Accordingly, embodiments having additional metal layers are exemplified in
Yet another exemplary embodiment appears in
Another mask-saving benefit of the exemplary embodiments discussed above is that additional masks are not used to form penetrating blades on the upper surfaces of the projections 22. In addition to allowing for a simpler fabrication process, these embodiments avoid the risk of a blade breaking off from one of the projections 22 in response to contact with the land of an LGA package. Moreover, these embodiments limit the damage done to the testing and tested devices more so than the bond-pad-penetrating blades of prior art silicon interconnects and the pins of prior packaged part testing equipment.
One skilled in the art can appreciate that, although specific embodiments of this invention have been described above for purposes of illustration, various modifications may be made without departing from the spirit and scope of the invention. For example, it is possible in one exemplary embodiment to retain the mask layer used to define the projections 22 seen in FIG. 1. That patterned layer, which can be Si3N4, can serve in whole or as part of the passivation/insulation layer 24. Retaining that layer saves the time and effort of removing that mask material and may quicken the process of providing a continuous passivation/insulation layer 24, if such continuity is desired. In addition, it is not required under the current invention to define the projections with an anisotropic etch; other exemplary embodiments include those wherein the projections result from an isotropic etch.
Moreover, the configuration of contact members may vary from the ones described above.
Furthermore, it is not necessary that the members have planar contact surfaces. Exemplary embodiments of the current invention also include those wherein the interconnect's contact members, while non-planar, nevertheless have portions that are configured to be parallel to corresponding portions of the packaged part's contact. An exemplary method embodiment capable of achieving such a configuration is illustrated beginning with FIG. 13A. That figure indicates that a mask 1700 is deposited over substrate 20 and patterned. A subsequent etch creates the recess 1702 seen in FIG. 13B.
Concerning the use of contact members, it should be noted that contact members such as the ones described above may be used in conjunction with packages other than an LGA package. For example, as shown in
Further, not only will the above-mentioned methods and devices work for silicon inserts and interconnects in general, but they have applications in other contexts as well. For example,
As an alternative to or in addition to the electrical connectors 1400 forming part of a test head, it may be desirable to include at least one electrical connector 1500 as part of a chip carrier 1506, as seen in FIG. 16. The chip carrier 1506 can be configured to allow electrical communication between each contact point of each socket 1504 to an electrical connector 1500. Once again, the electrical connectors 1500 can terminate with a material similar to the material to be contacted.
Yet another alternative embodiment appears in
Moreover, the methods and devices described above are not limited to testing circumstances; rather, they could also be used for interconnect devices in permanent or semipermanent packaging. Accordingly, the invention is not limited except as stated in the claims.
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