How to Build a Better Mousetrap Using Patent Searching for Better, Faster, and Cheaper Engineering Research and Product Development

Transcription

1 How to Build a Better Mousetrap Using Patent Searching for Better, Faster, and Cheaper Engineering Research and Product Development Craig A. Fieschko, Patent Attorney DeWitt Ross & Stevens S.C. Telephone: (608) cf@dewittross.com IMPORTANT NOTE: The information in this brochure is prepared for general informational purposes only and is not intended to constitute professional legal advice regarding your particular situation. Only an attorney can evaluate your situation and give you appropriate legal advice specific to your case. The information in this brochure is distributed "as is," with no guarantees regarding its accuracy, completeness and timeliness; therefore, neither the author nor DeWitt Ross & Stevens S.C. assumes any responsibility for any error, omission, or inaccuracy. Do not rely on any of this information before confirming it , Craig A. Fieschko, Esq. This document may only be reproduced in its entirety. Questions? Suggestions on how this paper could be improved? Please contact the author using the information above.

2 TABLE OF CONTENTS Use of This Paper...1 A. Introduction: What Are Patents (and What Can They Do For Me)?... 1 B. The USPTO Search Engines (and How to Get There)... 1 B.1 How to Access the USPTO Patent Search Engine... 1 B.2 How to Access the USPTO Patent Application Search Engine... 1 B.3 Other Ways to Access the USPTO Search Engines... 2 C. Limitations of the USPTO Search Engines... 2 D. Submitting a Search Query to the USPTO Search Engines... 4 E. Obtaining the Full Text and/or Image of a Selected Document... 4 F. Generating Search Queries: Overview... 5 F.1 Details on Logical (Boolean) Search Query Expressions... 6 F.2 Details on String Grouping (Phrase Searching) in Search Queries... 6 F.3 Details on Right Truncation ($ Wildcard) in Search Queries... 7 F.4 Details on Date Range Searching in Search Queries... 8 F.5 Details on Fielded Searching in Search Queries... 8 G. Getting Better Search Results (and Getting Them Faster)... 9 G.1 Better Search Results B In General... 9 G.1.a Searching in Technological Fields Versus Bibliographic Fields... 9 G.1.b Limitations of Abstract (ABST) and Title (TTL) Searching... 9 G.1.c Searching in the U.S. Classification (CCL) and International Classification (ICL) Fields G.2 The Best Search? G.2.a Rudimentary Search G.2.a.(1) Find "Starting Patents" G.2.a.(2) Find "Upstream Patents" G.2.a.(3) Find "Downstream Patents" G.2.b Follow-Up Search G.2.b.(1) Extended Rudimentary Search G.2.b.(2) Classification Search G.2.b.(3) Pending Patent Applications G.2.b.(4) Outside Search G.2.b.(5) Patent Search Engines of Foreign Patent Offices APPENDIX...16

3 Page 1 Use of This Paper The body of this paper (prior to the Appendix) discusses patent searching techniques. By using the Table of Contents, you should be able to skip to any portions of the body that are of immediate interest. The Appendix to this paper is then provided as a guide to the commands used by the United States Patent and Trademark Office (USPTO) search engines so that you can pull the Appendix off and use it when you're in front of a computer. A. Introduction: What Are Patents (and What Can They Do For Me)? A patent is often described as a government-granted monopoly provided to the inventor of a new and useful machine, process, or other invention in return for the inventor's complete disclosure of how to make and use the invention in a patent application. The inventor receives the patent monopoly B which is limited in time (generally to years) B in return for the disclosure, with the disclosure allowing the public to exploit the invention when the patent expires. Patents are therefore intended to build a library of knowledge for use in later technological innovation. The foundation of this library appears to be solidly built, since over nine million United States patents have been granted since the early 1800's in virtually every field of technology. Therefore, if you're interested in technological problem-solving and inventing, patents allow you to see how others have addressed problems that are the same or similar to the ones you're facing, and learn from their solutions. By using patents to determine the state of the art in your field, you can avoid "reinventing the wheel." However, this leads to another problem: with millions of patents to choose from, how do we find the ones that are relevant to the problems we want to solve? B. The USPTO Search Engines (and How to Get There) B.1 How to Access the USPTO Patent Search Engine The United States Patent and Trademark Office (USPTO), the division of the U.S. Department of Commerce entrusted with administration of the U.S. patent system, has provided an invaluable resource on the World Wide Web in the form of its USPTO Patent Search Engine. The USPTO Patent Search Engine allows full-text searching of most United States patents issued in approximately the last thirty years, and it also allows limited searching of older patents. As of November 2012, an address allowing direct access to the USPTO Patent Search Engine is B.2 How to Access the USPTO Patent Application Search Engine The United States Patent and Trademark Office (USPTO) also publishes some (but not all) pending patent applications B yet-to-be-issued patents B typically around 18 months after their earliest effective filing date. The full texts of published patent applications are also searchable, and these can effectively provide a preview of future patents (though it should be kept in mind

4 Page 2 that not all pending patent applications will actually proceed to issuance as patents). Since patent applications typically undergo revisions before being issued as patents, the published patent applications can also illustrate Aprior drafts@ of already-issued patents. As of November 2012, an address allowing direct access to the USPTO Patent Application Search Engine is B.3 Other Ways to Access the USPTO Search Engines The United States Patent and Trademark Office (USPTO) has been known to occasionally change the foregoing addresses for the Patent Search Engine and Patent Application Search Engine as service capacity is increased. If the foregoing addresses don't work, a web search for PatFT, the nickname for the Patent Full-Text Database, or for AppFT, the nickname for the Patent Application Full-Text Database, will typically lead you to the desired Search Engine. This paper then provides a guide for use of the Advanced Search option available in these Search Engines. C. Limitations of the USPTO Search Engines While the USPTO Search Engines are an excellent resource, it is important to note that they are subject to limitations. The most commonly encountered problems are: Only Patents Dating from 1976 Onward are Fully Searchable. The USPTO Patent Search Engine only allows full-text searching of U.S. patents dating from 1976 onward (at the earliest). Earlier patents can be accessed by patent numbers and patent classes (discussed at Sections 5 and 11 of the Appendix), but not by a text search of their contents. While pre-1976 patents may seem dated B they are over a third of a century old, and expired B they can contain "forgotten technology" and other valuable information, and can still be highly relevant to research, development, and patentability. Not All Patent Applications Are Available. The USPTO Patent Application Search Engine only allows full-text searching of published U.S. patent applications from 2001 onward (at the earliest). Since an applicant can opt out of publication of its application if it asserts that no corresponding patents will be sought outside of the United States, not all patent applications are published. Thus, one can't expect the USPTO Patent Application Search Engine to include all Aforthcoming patents.@ Data Errors Can Limit Results. The USPTO Search Engines may have missing documents, or missing or "distorted" portions of documents. A common problem is misspellings and typographical errors: patents or applications may fail to turn up in a search because the search terms used in a query don t match the misspelled terms contained within the USPTO database.

5 Page 3 Nonuniform Terminology and ALegalese@ May Compound Search Difficulties. Searches for some inventions B particularly mechanical and electrical inventions B can be difficult because many components can be given a wide variety of different names. Unless all potential names are searched, relevant inventions can be missed. The problem is compounded by a policy of the USPTO that each patentee "may be his/her own lexicographer": in other words, inventions and their components can be given any name whatsoever so long as it is not absurd or confusing. To illustrate, if one is searching for the term "screw", it would also be wise to search for the terms Abolt@ and Afastener@ B and to be truly complete, to also search for Aconnector,@ Aaffixment member,@ Aconnection pin,@ Afastening means,@ etc. All of these terms can be (and have been) used in place of "screw." If the circumstances call for a higher degree of accuracy and completeness in the search results B for example, if you're about to embark on an expensive program of research and development B you may want to contact a patent attorney to discuss advanced search tools and techniques. It can be expensive to commission a professional patent search, and/or to gain access to advanced patent databases, but in some cases the results can justify the cost. It s important to note that this paper focuses on patent searching for technical reasons B for problem-solving and innovation. If you're searching for patents owing to legal considerations B for example, to determine whether an invention is patentable, or whether it infringes a prior patent B you really should get the assistance of a patent attorney. If you don t fully understand what the law regards as important to patentability or infringement, you may not be looking in the right places. As an old saying goes, anyone who serves as his own attorney has a fool for a client. Nonetheless, this leads to an important point regarding patentability searches, whether they re performed by you or your attorney: they re never guaranteed, since the search performed by the USPTO when it examines your patent application will always be better than yours. When you apply for a patent, you re legally obligated to provide the USPTO with all known relevant search results. Thus, even if your invention seems to meet the key requirements for patentability after an exhaustive search your invention seems new and unobvious keep in mind that you ll have to provide your search results to the USPTO, which will then search even further. The USPTO s search will therefore by necessity go beyond your search, and may squelch patentability though your search results seemed positive.

6 Page 4 D. Submitting a Search Query to the USPTO Search Engines The basic steps for submitting a search query are simple. Once you access either of the USPTO Patent Search Engine or the Patent Application Search Engine: 1. Select a year or range of years to search from the "Select Years" drop-down menu situated below the "Query" text entry box. As of 2012, the Patent Application Search Engine only allows searching in a single range (from 2001 to present), but the Patent Search Engine allows a variety of year ranges (and full-text searching is only allowed on patents dating from 1976 onward). Don't forget to select the date range you want, or you may not get the desired search results. 2. Type your search query into the "Query" text entry box. Section F of this paper will discuss how to construct appropriate search queries. 3. Hit the "Search" button. Once a search query has been entered, the search results and a "hit list" of up to the 50 most recent documents (patents or applications) answering the search query will be displayed, listing their patent numbers or published application numbers, and their titles. The documents are arranged in ascending age order (i.e., newer documents are listed first). Hitting the "Next 50 Hits" button will take you to the next 50 documents. Alternatively, you can enter a hit number in the box next to the "Jump To" button and hit the button to skip to another list of 50 documents containing that hit number. For example, with a long search results list, entering "251" in the "Jump To" box yields faster results than hitting the "Next 50 Hits" button 5 times. E. Obtaining the Full Text and/or Image of a Selected Document By clicking on the document number or title of a selected document, you can access the Full Text of the document. You can also get an Image Copy of the actual document (with drawings, etc.), by hitting the "Images" button near the top of the page to display printable images of the document, so long as you have the appropriate plug-in for your browser. Several free plug-ins are listed at Unfortunately, as of December 2012, all free plug-ins only print out free patent copies from the USPTO website one page at a time (you have to view each page to print it), which can be inconvenient. Other sites, readily findable by searching "free full patent pdf" or the like (or by accessing the Google Patents feature of the Google search engine), allow downloads of complete patents in PDF format upon entering their patent numbers.

7 Page 5 F. Generating Search Queries: Overview Search queries in the USPTO Search Engines make use of the following features: Case-Insensitive. The USPTO Search Engines don t discriminate between upper- and lower-case letters. Searching for any of "MOSFET", "Mosfet" and "mosfet" will produce the same results. Fielded Searching (also see Section F.5 of this paper for more details). The USPTO Search Engines use "fielded" searching, wherein the data contained in each document is catalogued by its field: the patent or application title, the date of the application=s filing, the date of the patent's issuance, the specification (i.e., the body of the document), etc. For example, if you're searching for a particular patent number or inventor name, you can enter a field code for the "Patent Number" or "Inventor Name" fields (i.e., you can enter field codes "PN/" or "IN/") prior to the patent number or inventor name you're searching. If you type in the search terms of interest without specifying a field in which to search for them, the search engine will locate documents having the specified search terms anywhere in the document. The various field codes and their meanings are discussed in the Appendix of this paper. Use of field codes is discussed at greater length in Section F.5 of this paper. Logical (Boolean) Expressions (also see Section F.1 of this paper for more details). The USPTO Search Engines require use of one of the Boolean expressions OR, AND, and ANDNOT between any two separate search terms. Boolean expressions can be grouped/nested, such as X AND (Y OR Z). String Grouping/Phrase Searching (also see Section F.2 of this paper for more details). Quotation marks can be used to search for phrases (strings of search terms). For example, a query of "load cell" will find patents containing the words "load" and "cell" situated adjacent to each other, in that order. Truncation/Wildcards (also see Section F.3 of this paper for more details). The USPTO Search Engines allow some degree of usage of truncation, also known as wildcards, to accommodate for varying forms of the same search term. The wildcard for right truncation is $ (e.g., "rivet$" for rivets, riveting, riveter, etc.). Left truncation (e.g., "$chip" for microchip, biochip, nanochip, etc.) is not allowed. Date Range Searching (also see Section F.4 of this paper for more details). The USPTO Search Engines will allow specified ranges of numerical data to be searched by use of the A->@ operator, but only where the numerical data is date data. In other words, specified date ranges within the Patent Issue Date (ISD), Patent Application Filing Date (APD), and Patent Application Publication Date (PD) fields (see Sections of the Appendix) may be searched.

8 Page 6 Stopwords. The USPTO Search Engines exclude stopwords from their searches: terms that are so common in everyday language and in patent texts that they have no practical use as search terms (e.g., "the", "in", "when", etc.). Stopwords in the search query are simply ignored. Overcoming Errors. If a complex fielded search results in a message that a processing error occurred, it may help if the search query is re-run without field codes (so that the entire patent text is searched). While this sometimes cures the processing error, it unfortunately broadens the search and can lead to a greater number of irrelevant results. F.1 Details on Logical (Boolean) Search Query Expressions The USPTO Search Engines allow the use of the Boolean operators OR, AND, and ANDNOT between search terms. Parentheses can also be used to further clarify a search query. In the absence of parentheses, all Boolean operators associate from left to right. Example 1: tennis AND (racquet OR racket) This query returns a list of documents which contain both (1) the term "tennis" and (2) either of the terms "racquet" or "racket" somewhere in the document. Example 2: television OR (cathode AND tube) This query returns a list of documents which contain either (1) the word "television" or (2) both of the words "cathode" and "tube". Example 3: needle ANDNOT ((record AND player) OR sewing) This query returns a list of documents which contain the word "needle", but does not contain any references to (1) "sewing", or (2) both of the words "record" and "player". Example 4: AN/United AND (TTL/solder OR TTL/braze) or AN/United AND TTL/(solder OR braze) As this example demonstrates, you can mix field searching (as discussed in Section F.5 of this paper) with Boolean searching. This query returns a list of documents which contain "United" in the Assignee Name (AN) field (as discussed at Section 18 of the Appendix), and the word "solder" or "braze" in the Document Title (TTL) field (as discussed at Section 3 of the Appendix). Note that field names are associative; using the search statement TTL/(solder OR braze) is the same as (TTL/solder OR TTL/braze). F.2 Details on String Grouping (Phrase Searching) in Search Queries A group of words enclosed in quotation marks (") will be treated as a single search term. This allows you to search for a multi-word phrase rather than having to enter each word as a separate search term. As an example, Ageneral electric@ can be used instead of general AND electric.

9 Page 7 You can't truncate within a phrase (use wildcards within a phrase) that is enclosed in quotation marks. For example, attempting to search for any assignee (owner) named AGeneral Electric,@ AGeneral Electrics,@ AGeneral Electrical,@ etc. by using the query AN/"general electric$" will result in an error. A query such as AN/general AND AN electric$ would be needed instead. Example 1: "bowling balls" Searching this phrase returns a list of documents which have the phrase "bowling balls" anywhere within the indexed text. Example 2: AN/"General Electric" or AN/"general electric" This query returns documents having the phrase "General Electric" within the Assignee Name (AN) field (as discussed at Section 18 of the Appendix). F.3 Details on Right Truncation ($ Wildcard) in Search Queries The USPTO Search Engines support right truncation in queries. This allows you to use a wildcard (more specifically, the $ wildcard) on the right side of a string of characters to retrieve words that begin with this string. A truncated string must be at least 3 characters in length if a field is specified for the string. As an example, a search of patent titles using the Document Title (TTL) field could use ATTL/bio$@, but not ATTL/bi$@. If no field is specified for the string, the string must be at least 4 characters in length to utilize truncation. Also, recall that an unfielded search will search every word in every document in the year(s) you specify. Since use of truncation effectively expands a search, an unfielded search (which is broader than a fielded search) can sometimes result in a very large number of hits if truncation is used. Truncation can't be used in strings enclosed in quotation marks. For example, using the query AN/"general electric$" to search for any assignee (owner) named AGeneral Electric,@ AGeneral Electrics,@ AGeneral Electrical,@ etc. will result in an error. A query such as AN/general AND AN electric$ would be needed instead. Left truncation isn't allowed. "spectroscope," etc. Thus, you can't use "$scope" to locate "microscope," Example: elec$ This query would return a large number of hits, since it would retrieve patents that contain the words "electricity", "electric", Aelection,@ Aelective,@ etc. Hits could be reduced by truncating a longer string; for example, if you're only interested in patents dealing with electronics, electron$ would eliminate "electricity" and other non-"electron-" terms.

10 Page 8 F.4 Details on Date Range Searching in Search Queries If you're searching date-related fields (e.g., Patent Issue Date, Patent Application Filing Date, Patent Application Publication Date), you can specify a range of dates you're interested in searching, rather than specifying precise dates (which might overly limit your search). This feature is only available in date fields, such as Patent Issue Date, Patent Application Filing Date, and Patent Application Publication Date. Ranges are searched by using the A->@ operator between two dates. The specified dates must be properly formatted for the search to work. See the entries on Patent Issue Date (ISD) at Section 14 of the Appendix, Patent Application Filing Date (APD) at Section 15 of the Appendix, and Publication Date (PD) at Section 16 of the Appendix for details. Example: ISD/11/1/1997->5/12/1998 This query would return patents issued any day on or after November 1, 1997, and on or before May 12, F.5 Details on Fielded Searching in Search Queries Within the USPTO Search Engines, documents are divided into many fields, such as inventor name, patent number, patent specification, etc. By narrowing your search so that a document is only counted as a "hit" if the term you're searching occurs in the field you specified, you can greatly decrease the number of irrelevant documents returned. To narrow your search to hits occurring within a particular field, precede your search term with the proper field code, followed by a forward slash (/). Details on the field codes are given in the Appendix. Always remember that if you don t specify search fields (field codes), the entire texts of the documents in the chosen USPTO Search Engine database will be searched. Example 1: IN/Dobbs or IN/dobbs Entering this query in the USPTO Patent Search Engine or USPTO Patent Application Search Engine will search for the word "Dobbs" within the Inventor Name (IN) field of all documents in the chosen database (see the discussion of the IN field at Section 23 of the Appendix). Occurrences of the search term anywhere else in the database will be ignored. Example 2: CCL/270/31 This query will return a list of documents within United States Patent Classification 270/31 (see the discussion of the CCL field at Section 5 of the Appendix). Example 3: AN/United AND (TTL/solder OR TTL/braze) or AN/United AND TTL/(solder OR braze)

11 Page 9 As this example demonstrates, you can mix field searching with Boolean searching (as discussed in Section F.1 of this paper). This query would return a list of documents which contain "United" in the Assignee Name (AN) field (as discussed at Section 18 of the Appendix), and the word "solder" or "braze" in the Document Title (TTL) field (as discussed at Section 3 of the Appendix). Note that field names are associative; using the search statement TTL/(solder OR braze) is the same as (TTL/solder OR TTL/braze). G. Getting Better Search Results (and Getting Them Faster) G.1 Better Search Results B In General Following are some general tips on obtaining better search results. G.1.a Searching in Technological Fields Versus Bibliographic Fields As noted in the Appendix, certain fields can be regarded as technological fields: they relate more to the technology of the invention than the history of its patent or application. These are the best fields to search when you're looking for details about a particular technology regardless of who developed it, when it was developed, who owns it, etc. The remaining fields can be regarded as bibliographic fields: they relate more to the history of the patent than the technology of the invention. These fields are good to search if you know something about the history of the patent B for example, its inventor(s), the name of the patent owner/assignee, when the patent might have issued, or other facts of this nature. G.1.b Limitations of Abstract (ABST) and Title (TTL) Searching Limiting a search to the Abstract (ABST) and/or Title (TTL) fields of patents or applications (discussed in Sections 2 and 3 of the Appendix) will often result in incomplete search results. These fields may be useful to start a search, but it is best to extend the search to the Specification (SPEC) field B i.e., to the body of the documents B for complete search results. Searching only abstracts and/or titles can miss important documents because abstracts and titles are inherently short in length, and are often vaguely worded, which can make it difficult to specify the full range of Abuzzwords@ necessary to locate all relevant documents. Also, it=s an unfortunate fact that abstracts are often drafted rapidly and with minimal attention when a patent application is prepared. As a result, there are many abstracts and titles which don t fully represent the contents of their patents, and an abstract and/or title search should never be regarded as complete and accurate. A Specification (SPEC) search (discussed in Section 1 of the Appendix), which extends to the detailed body of the patent or application, is far more complete. Nevertheless, if your search strategy results in a very large number of hits B which may occur after using a default (unfielded) search, or if you search in the Specification (SPEC) field for common terms B it may be preferable to begin your search by limiting it to the Document Title (TTL) or Document Abstract (ABST) fields.

12 Page 10 G.1.c Searching in the U.S. Classification (CCL) and International Classification (ICL) Fields During the examination of a patent application, the USPTO will assign the application (and its later-issued patent) U.S. Classification and International Classification codes B codes which are supposed to identify the specific field(s) of technology to which the document relates. In essence, the U.S. Classification and International Classification codes are like ADewey decimal numbers@ relating to technology. As a result, searching for technology in the U.S. Classification (CCL) field, and to some degree the International Classification (ICL) field (discussed in Sections 5 and 6 of the Appendix), will often yield the best search results. Unfortunately, classification searches can be the most difficult to perform because it usually takes significant experience with the U.S. and International Classification systems before one can quickly and accurately locate the proper classifications relating to a technology in question. Section G.2 of this paper discusses a strategy that can greatly simplify classification searching, but if you wish to bypass the simplified method, following is a Abrute force@ method of using the U.S. Classification system. The object of a classification search is to use the USPTO Manual of U.S. Patent Classification to identify the patent classes and subclasses which are most relevant to your technology of interest, and then use the U.S. Classification (CCL) field and/or the International Classification (ICL) field to obtain patents in these classes and subclasses for further review. The USPTO Manual of U.S. Patent Classification, which indexes the U.S. classification numbers to their relevant field of technology, is available as of November 2012 on the World Wide Web at: If this link is out of date, go to the USPTO home page ( and try searching for "classification.@ A good way to start is to search the Manual=s Index (usually labeled AIndex to Classification@) for terms describing your technology of interest B its components/structure, function/use, and end effect. This search will return classes and subclasses of potential interest. You can then enter these classes/subclasses in the Class Definition (a general description of the technologies in each class and subclass), and/or in the Class Schedule (a more specific description of the technology), to see if the identified classes/subclasses appear to be truly relevant. Pay particular attention to cross-references to other classes of potential search interest in the Class Definition, and also to surrounding subclasses in the Class Schedule, since some of these may be more relevant to your technology. Always keep in mind that many technologies can fall into multiple classes and subclasses.

13 Page 11 Once you=ve identified your classes/subclasses of particular interest, you can then restrict your search to the U.S. Classification (CCL) field (discussed in Section 5 of the Appendix). You can obtain and review all patents in a class/subclass of interest by simply entering ACCL/[class/subclass of interest]@ (taking care to select the proper range of dates for searching), or you can couple searching in the U.S. Classification (CCL) field with other fields of interest (e.g.,accl/702/98 AND SPEC/gage@). If you wish, you can also (or alternatively) search the International Classification (ICL) field, which contains the technology classification(s) specified by the World Intellectual Property Organization (WIPO). The International Classification system is separate from (but generally parallel to) the U.S. Classification system, though some International classes/subclasses may be broader than (or narrower than) corresponding U.S. classes/subclasses. Therefore, searching a particular International class/subclass may return more (or fewer) search results than searching an (allegedly) parallel U.S. class/subclass. The Classification Concordance, which lists the International Classification(s) that the USPTO regards as corresponding to each U.S. Classification, is available as of November 2004 on the World Wide Web at: Concordance: (enter the U.S. Classification and request AUS-to-IPC Concordance@) If this link is out of date, go to the USPTO home page ( look for the ASite Index@ link (generally near the top of the page), and look under "classification.@ Again, classification searching can be time-consuming and frustrating unless you=re highly familiar with the USPTO Manual of U.S. Patent Classification. Thus, you may prefer to use the search strategy noted in Section G.2 of this paper to identify any classes/subclasses of interest. Also note that classification searching alone will not always yield the best search results. Technically, the classification assigned to a patent or application is supposed to focus on the matter of the document's claims the numbered sections at the end of the document that define the specific matter covered (or intended to be covered) by patent rights. (Claims are discussed further at Section 4 of the Appendix.) Since claims often cover only specific features of an invention, the class(es) assigned to a document may not relate to invention features of interest which are described in the document, but which aren't claimed. Also, owing to the difficulties involved with accurately assigning classes/subclasses to a patent or application, many documents are not optimally classified. Thus, it is recommended that classification searching always be coupled with other search strategies discussed in this paper.

14 Page 12 G.2 The Best Search? Following is a search strategy which often yields the best results when you're searching for a particular technology. Of course, since the best search strategy for any search will depend on the particular details of that search, you may want to modify the following strategy in accordance with the considerations noted in Section G.1 of this paper. G.2.a Rudimentary Search The first step is to perform a rudimentary search which locates one or more patents which have strong relevance to your technology of interest. You can then expand on the rudimentary search using the methods described in Section G.2.b of this paper. Often, a good rudimentary search can be performed using the following steps. G.2.a.(1) Find "Starting Patents". In the USPTO Patent Search Engine (rather than in the Patent Application Search Engine) which, again, is found at as of November perform a general technological search to find a few "starting patents" which are representative of the results you're looking for. At this point, you're not looking to find all the best patents B you just want to find a few. In general, it helps to start by searching in the Specification (SPEC) field. If you get too many hits, try searching in the Document Abstract (ABST) and/or Document Title (TTL) fields. As discussed at Sections 2 and 3 of the Appendix, beware of relying solely on searches of the Document Abstract (ABST) and/or Document Title (TTL). Once you have a few starting patents, save copies. G.2.a.(2) Find "Upstream Patents". From the text of the starting patents, take note of their Cited U.S. References (REF). These are listed on the front page of the printed patent, or if your browser is displaying a text-only version of a patent, the Cited U.S. References (REF) should be listed on one of the first few pages under the heading "References Cited". The Cited U.S. References (REF) are the patents that were regarded by the USPTO as being technologically relevant to the starting patents. Therefore, the patents listed as Cited U.S. References (REF) for the starting patents might be regarded as upstream patents: they came prior to the starting patents, and are (supposedly) in the same technological field. Note that not all upstream patents may be relevant to what you're looking for. Some of them may have been cited by the USPTO because they were relevant to only some subcomponent or small feature of the starting patent in which they are cited. If any upstream patents are relevant to what you're looking for, save copies. G.2.a.(3) Find "Downstream Patents". We now want to look for patents which are downstream from the starting patents and the upstream patents: patents which are later than the starting and upstream patents, and are (supposedly) in the same technological field. This can be done in one of the following ways:

15 Page 13 If your browser is displaying the full-text version of any starting or upstream patent, look for and click on the "Referenced By" link (which, if present, is set forth a page or two into the patent text adjacent to the "References Cited" heading). This is usually the easiest way to access downstream patents. Downstream patents can also be found by searching for the patent numbers of the starting and upstream patents in the Cited U.S. References (REF) field. For example, if you have U.S. Patent 6,526,939 and U.S. Patent 6,668,789 as your starting and upstream patents, entering REF/6,526,939 AND REF/6,668,789 or REF/ AND REF/ will yield a list of the downstream patents (if any). Either of these steps will find all downstream patents: patents later than the starting (or upstream) patent which list the starting (or upstream) patent as a Cited U.S. Reference (REF). Be aware that some patents, particularly recent ones, may not yet have any downstream patents. Also, as with upstream patents, some of the downstream patents may not be very relevant to what you're looking for, because the downstream patents may have cited the prior patents for some minor point rather than for your topic of interest. If any downstream patents are relevant to what you're looking for, save copies. G.2.b Follow-Up Search By obtaining the relevant starting patents, upstream patents, and downstream patents, you should have a good rudimentary search. Note that you have effectively searched the "family tree" for the starting patents: you looked at the prior patents that were regarded as being relevant to the starting patents, and then looked at the later patents that regarded the prior patents as being relevant. Following are steps you can take to make the search results more robust. G.2.b.(1) Extended Rudimentary Search. You can further expand the results of the rudimentary search by going further downstream (i.e., go downstream from the downstream patents) or upstream (i.e., go upstream from the upstream patents), thereby extending the aforementioned "family tree." G.2.b.(2) Classification Search. This step can help to find patents that are technologically relevant, but which for some reason were not cited as (and did not cite to) relevant prior patents B in other words, patents which were for some reason omitted from the aforementioned "family tree." Here, we want to find the patent classifications of the starting patents, upstream patents, and downstream patents, and then search for other patents having the same classification. (Note that patent classifications are discussed in Sections 5 and 6 of the Appendix.)

16 Page 14 If you're looking at images of a printed patent, its U.S. Classification (CCL) is listed on the front page under "U.S. Cl." and its International Classification (ICL) is listed under "Int. Cl." If your browser is displaying the full-text version of a patent, look for the "Current U.S. Class" and "Current International Class" headings. Note that if you're looking at images of a printed patent, the class(es) listed thereon may be obsolete owing to updates in the classification system. Thus, it can be useful to access the full-text version of the patent on the USPTO Patent Search Engine to verify the current class(es). Once you've compiled a list of the patent classifications from your starting patents, upstream patents, and downstream patents, you can then run a search query in the U.S. Classification (CCL) field, and/or in the International Classification (ICL) field, for other patents having the same classes. For example, entering ACCL/270/31" will return a list of all patents in class 270, subclass 31 in the date range that you selected. If your collection of the starting patents, upstream patents, and downstream patents repeatedly list a certain few patent classes under U.S. Classification (CCL) and/or the International Classification (ICL), these patent classes are probably more relevant to what you're looking for than patent classes that are listed less frequently. G.2.b.(3) Pending Patent Applications. You can then locate documents which are even further Adownstream@ from the patents you=ve located by using the USPTO Patent Application Search Engine to search pending U.S. patent applications: documents which may issue as patents, provided the United States Patent and Trademark Office (USPTO) finds them suitable for patenting. Again, as of November 2012, the USPTO Patent Application Search Engine can be found at The following characteristics of the USPTO Patent Application Search Engine are useful to remember when searching patent applications. G.2.b.(3)(a) Different Fields and/or Treatment of Fields. While the USPTO Patent Application Search Engine can be searched using generally the same fields and strategies as those usable in the USPTO Patent Search Engine, it does not use all of the same fields as the USPTO Patent Search Engine, and some of the fields that it does share with the USPTO Patent Search Engine are treated differently. Differences are discussed in the Appendix. G.2.b.(3)(b) Not All Patent Applications are Available. An applicant can request that its application not be Apublished@ (i.e., made publicly available before issuance as a patent), in which case the application will not be available in the USPTO Patent Application Search Engine. Otherwise, the database of the USPTO Patent Application Search Engine generally only includes patent applications having an effective filing date which is at least 18 months old, unless the applicant requested that the USPTOApublish@ (make available) the application earlier.

17 Page 15 G.2.b.(3)(c) Overlap With the USPTO Patent Search Engine. Since the USPTO Patent Application Search Engine database generally only includes applications that have an effective filing date which is at least 18 months old, at least some of the applications that are returned as search results may have already issued as patents. In other words, while searching the USPTO Patent Application Search Engine may yield some pending patent applications that have not yet issued as patents (or which did not or may not issue as patents), it may also yield patent applications which are redundant with the results yielded by searching the USPTO Patent Search Engine (in that you can find the issued patent as well as its patent application). G.2.b.(3)(d) Application Contents May Change. Patent applications are often modified after they re filed, so the contents of any application you see may not accurately reflect the contents of any patent to issue from the application. In other words, when you view a patent application, you re viewing a Awork in progress." In particular, the application's claims and patent classes (discussed at Sections 4 and 5 of the Appendix) often change before a patent application issues as a patent. G.2.b.(4) Outside Search. You can also take note of the Cited Foreign References (FREF) and Other References (OREF) cited by the U.S. Patent and Trademark Office (USPTO) in the starting, upstream, and downstream patents, and obtain copies from a library, or from an online source (see Section G.2.b.(5) below). These fields are discussed in Sections 8 and 9 of the Appendix. G.2.b.(5) Patent Search Engines of Foreign Patent Offices. The USPTO Search Engines only allow searching of U.S. patents and patent applications. Some foreign patent offices have search engines available on the World Wide Web for searching non-u.s. patents. Of these, the best known are the "Espacenet" search engine of the European Patent Office, available (as of November 2012) at and the search engine of the World Intellectual Property Organization (WIPO), available (as of November 2012) at WIPO administers the Patent Cooperation Treaty (PCT) system of PCT Patent Applications (sometimes referred to as "International Patent Applications"), discussed at Section 33 of the Appendix.

18 Page 16 APPENDIX Searchable Data Fields in the USPTO Search Engines A summary of field codes and their meanings is provided below, with a detailed explanation of each field code then being set forth at the indicated page. Field codes designated with *PAT* are only usable in the USPTO Patent Search Engine to search issued patents. Field codes designated with *APP* are only usable in the USPTO Patent Application Search Engine to search patent applications. Technological Fields 1. Description/Specification (SPEC)... Page Document Abstract (ABST)... Page Document Title (TTL)... Page Patent Claim(s) (ACLM)... Page U.S. Classification (CCL)... Page International Classification (ICL)... Page Cited U.S. References *PAT* (REF)... Page Cited Foreign References *PAT* (FREF)... Page Other Cited References *PAT* (OREF)... Page 21 Bibliographic Fields 10. Application/Patent Type *PAT* (APT)... Page Patent Number *PAT* (PN)... Page Document (Application Publication) Number *APP* (DN)... Page Patent Application Serial Number (APN)... Page Patent Issue Date *PAT* (ISD)... Page Patent Application Filing Date (APD)... Page Patent Application Publication Date *APP* (PD)... Page Document Kind *APP* (KD)... Page Assignee (Owner) Name (AN)... Page Assignee (Owner) City (AC)... Page Assignee (Owner) State (AS)... Page Assignee (Owner) Country (ACN)... Page Government Interest (GOVT)... Page Inventor Name (IN)... Page Inventor City (IC)... Page Inventor State (IS)... Page Inventor Country (ICN)... Page Primary USPTO Examiner *PAT* (EXP)... Page Assistant USPTO Examiner *PAT* (EXA)... Page Legal Representative *PAT* (LREP)... Page Related U.S. Application (RLAP)... Page 30

19 Page Parent Case Information *PAT* (PARN)... Page Foreign Priority (PRIR)... Page PCT Information (PCT)... Page Reissue Data *PAT* (REIS)... Page Description/Specification (SPEC) The Description/Specification (SPEC) field finds patents or applications containing the term(s) specified in the SPEC field within the bodies of the documents. The body (the description or specification) contains a description of how to make and use the invention in question, given in such detail that anyone familiar with the state of the art should be able to make and use the invention, and will often include details on the background of the invention (prior inventions in the field, and the problems that the invention is supposed to address). Because this field is the most detailed one, it generally returns the best results when searching for details on a particular technology. SPEC/naphthoquinones finds patents or applications containing Anaphthoquinones@ in the body of the document. SPEC/electrophor$ AND TTL/@conductive polymers@ finds patents or applications containing Aelectrophoresis,@ Aelectrophoretic,@ etc. in the body of the document AND having Aconductive polymers@ in the title (see the description of the Document Title (TTL) field at Section 3 of this Appendix). 2. Document Abstract (ABST) The Document Abstract (ABST) field finds patents or applications containing the term(s) specified in the ABST field within the abstracts of the documents. The abstract contains a brief summary of the invention in question, and like the document title (TTL), it can contain many of the most relevant words of a patent. However, since abstracts are supposed to be short in length, and they are often not given significant attention when the patent application is drafted and processed, there are many abstracts which don t fully represent the contents of their patents. Thus, an abstract search should never be regarded as complete and accurate. A Description/Specification (SPEC) search (discussed at Section 1 of this Appendix) is far more complete. ABST/microencapsulated finds patents or applications containing Amicroencapsulated@ in the abstract of the document. ABST/@load cells@ AND TTL/fluid finds patents or applications containing Aload cells@ in the abstract of the document AND having Afluid@ in the title (see the description of the Document Title (TTL) field at Section 3 of this Appendix). 3. Document Title (TTL) The Document Title (TTL) field finds patents or applications containing the term(s) specified in the TTL field within the titles of the documents. A title search alone should never be regarded as complete and accurate, since documents dealing with very similar inventions can nevertheless have very different terms in their titles, and thus it is easy to miss relevant documents. A Description/Specification (SPEC) search (discussed at Section 1 of this Appendix) is far more complete.

20 Page 18 TTL/bulkhead finds patents or applications containing in the title of the document. TTL/recycl$ AND finds patents or applications containing etc. in the title of the document AND having Ahazardous in the abstract (see the description of the Document Abstract (ABST) field at Section 2 of this Appendix). 4. Patent Claim(s) (ACLM) The Patent Claims (ACLM) field finds patents or applications containing the term(s) specified in the ACLM field within the claims of the documents. The claims set forth a definition of the subject of the "patent monopoly" B that is, they define the invention(s) for which exclusive patent rights have been secured (or are being sought). The claims are supposed to encompass the portions of the invention that are new, unobvious, and useful, and thus they might seem to be an ideal area for searching. Unfortunately, this is often not the case; patent claims are intended for use more by attorneys and courts than by inventors or researchers, and thus they tend to contain "legalese," and are often broadly worded and lacking in technological detail. As a result, a search in the Patent Claims (ACLM) field is usually less useful than a search in the Description/Specification (SPEC) field and/or Document Abstract (ABST) field (discussed at Sections 1 and 2 of this Appendix). ACLM/naphthoquinones finds patents or applications containing Anaphthoquinones@ in the claims of the document. ACLM/mosfet$ AND SPEC/@harmonic wave@ finds patents or applications containing Amosfet@ or Amosfets@ in the claims of the document AND having Aharmonic wave@ in the body (see the description of the Description/Specification (SPEC) field at Section 1 of this Appendix). 5. U.S. Classification (CCL) The U.S. Classification (CCL) field finds patents or applications cross-referenced to the U.S. patent class(es) and subclass(es) specified in the CCL field (see the discussion in Section G.1.c of the accompanying paper). Patent classes/subclasses are alphanumeric codes used by the USPTO to signify that a document relates to a specific field of technology, and thus patent classes/subclasses are perhaps the best indicator of the invention's technological field. If you're searching for a specific class and subclass, you should phrase your query as class, forward slash, subclass (in class/subclass form) B for example, 2/5. Note that some subclasses can contain decimal and alphabetical modifiers (for example, 427/2.31 or 427/3A). CCL/2/5 finds patents or applications classified in U.S. patent class 2, subclass 5. NOTE: CAREFUL USE OF WILDCARDS. If you want to search class-wide (you don't want to limit to a particular subclass), use the $ wildcard. Example: a search for CCL/607$ will search across all subclasses in class 607. However, beware of the limitation (discussed in Section F.3 of the accompanying paper) that you can't use wildcards in strings that are (1) searched by field and (2) less than three characters long. Thus, you can't do a class-wide search in a two-digit class by use of wildcards (e.g., CCL/62$ will