Patent Law You Can Use: Reading a Patent
- By Howard M. Eisenberg
- Sep 01, 2003
A patent is a complex document made up of several parts, including a specification that describes the invention and how to make and use it, claims that specify what is protected by the patent and drawings if needed to understand the invention. Each patent has a cover sheet that contains important information about the patent. Information on the cover sheet is of interest to many different individuals, including the patentee, potential licensees, competitors, attorneys and judges.
For those unfamiliar with patents, the cover sheet may seem difficult to understand or even incomprehensible. Even for those who have worked with patents, the significance of some of the items on the cover sheet is not always fully understood.
Each item on the cover sheet has next to it a number inside a bracket, for example  next to the filing date. By international agreement, these numbers are used by all countries on their patent cover sheets to inform the reader what the individual items of information signify. For example, a person who cannot read Japanese would have a very difficult time determining which of the several dates found on a Japanese patent cover page refers to the filing date of the application. The bracketed number  next to a date indicates that this date is the filing date. This system ensures that certain information about the patent will be available to everyone, even without the ability to read the language of the patent.
Some items, such as the Title, Inventor and Patent Number, are found on the cover sheet of all U.S. patents. Other items, such as Assignee, Foreign Application Priority Data or Attorney, may be absent if they are not pertinent to the particular patent.
The most prominent portion of the cover sheet is the section at the top of the page containing information found on all U.S. patents. The first line on the left side contains the words "United States Patent," followed by . Under this is the last name of the first named inventor of the patented invention. In the upper right corner, there is a bar code that contains information about the patent number.
Below the bar code is  Patent Number. The number for a utility patent has seven digits, for example 5,478,814. A design patent number has six digits preceded by a capital "D," such as D123,456. A reissue patent (a patent that has been corrected by the issuance of a new patent) has a five-digit number with the letters "RE," such as RE.12,345. The patent number may have additional letters before or after the numbers, depending on when the patent issued. For utility patents issued after Jan. 2, 2001, patent numbers are followed by either "B1" or "B2."
B1 indicates that the patent was not published during the application process. B2 indicates that the patent was previously published when the patent was an application. The letter "E" appears following a reissue patent number for reissue patents after Jan. 2, 2001. The letter "S" follows design patents issued after Jan. 2, 2001. A re-examination certificate (a patent that had been reexamined because of newly discovered prior art) before Jan. 2, 2001 has a seven-digit number preceded by "B1" (or "B2" or "B3," to designate if this was the first, second or third reexamination), for example B1 5,123,456. Reexamination certificates issued after Jan. 2, 2001 omit the "B1" following the number. Instead, these more recent reexamination certificates have a "C1," "C2" or "C3" before the patent number to indicate the first, second, or third reexamination.
Below the Patent Number is  Date of Patent. This is the date that the patent issued and the date from which the patent is in force until it expires. Before June 8, 1995, all patents expired 17 years from the issue date, assuming that periodic patent maintenance fees were paid. Since then, determining the expiration date of a patent has become more complex. The filing date of the application and the existence of any parent applications now must be considered in order to determine when a patent will expire. In addition, an asterisk (*) sometimes appears before the issue date. This indicates that the term of the patent has been shortened and that the patent will expire on a date that cannot be determined solely by information found on the cover sheet of this patent.
Below the thin black line that separates the previously mentioned information from the rest of the cover sheet, the information is arranged in two columns, which are arranged as newspaper-type columns. The first item is  TITLE OF THE INVENTION, a name selected by the patentee to describe the invention.
Following this is  Inventors. The names and hometowns of all inventors of the patented invention are listed. In the United States, patent applications are filed in the name of the inventors. In other countries, the owner of an invention may file a patent application in his or her own name even if he or she is not the inventor.
Next is  Assignee. This is the name of the person or entity to which the ownership of the invention has been assigned, most commonly the company that employs the inventor. In order to have an assignee listed on a patent cover page, the assignment from the inventor to the assignee must be recorded with the Patent Office. If the patent has not been assigned or if the assignment has not been recorded, the Assignee field will be absent.
Occasionally, there will next be a [*] Notice. If an asterisk appears before the Date of Patent, this indicates that the patent will expire before its natural expiration date.
The next item is  Appl. No. This is the serial number assigned by the Patent Office to the application that was eventually issued as this patent. Patent application numbers are eight-digit numbers beginning with 08 or 09, followed by a slash, and then six numbers, for example 08/034,151. On the patent cover sheet, the two digits to the left of the slash are omitted. If the first digits to the right of the slash are zero, they are also omitted. Therefore, the application number 08/034,151 appears on the cover sheet as 34,151.
Following this is  Filed. This is the date that the application was filed in the U.S. Patent Office. This date is used to determine the expiration and priority dates of the patent, unless the patent is related to a previously filed parent application. Generally, for applications filed after June 8, 1995, the patent will expire 20 years from the filing date. For applications filed before June 8, 1995, and still pending on that date, the patent expires either 17 years from the issue date or 20 years from the filing date, whichever is later.
The next section on the cover page is Related U.S. Application Data. There is  a short paragraph that lists the parent applications of the patent and the outcomes of those applications in this section.
As an alternative to filing a patent directly in the U.S. Patent Office, an applicant may file an international patent application in accordance with the Patent Cooperation Treaty (PCT). After a processing period in the PCT receiving office that may last for up to 30 months, the patent application then enters into the national phase in the U.S. Patent Office, hopefully to issue eventually as a U.S. patent. The patent cover page, in this case, will not list the U.S. Filing date and Related U.S. Application Data. Instead, there will be data concerning the PCT application. The cover sheet will list the filing date of the PCT application , the PCT application number , the date the PCT application was entered into the U.S. Patent Office and became a prior art reference that could be applied against other U.S. patent applications, the date the PCT application was published, and the publication number .
If the application was filed in a foreign country prior to the filing date in the U.S. Patent Office or in the PCT, the cover page will list  Foreign Application Priority Data, showing the date filed, the country in which it was filed and the application number in that country.
The next three items are  Int. Cl.,  U.S. Cl. and  Field of Search. These are the International and U.S. classifications that are related to the field of the invention and the fields that the Examiner searched in examining the patent application. Information regarding the classification system can be found in the Manual of Classification, a publication of the U.S. Patent Office. The classification information is useful when searching for relevant prior art, such as when trying to invalidate a patent or to help in drafting a patent application in a field similar to this patent (www.uspto.gov is an online patent information tool that is available to the public).
The next item is  References Cited. This is a listing of all of the publications that were considered by the Examiner in deciding whether to grant the patent. First are U.S. Patents, for which the patent number, issue date, inventor and U.S. classification are listed. Next are Foreign Patent Documents, which may include patents and published patent applications. Finally, Other Publications, typically scientific articles, are listed. The listing of cited references is very important because there is a strong legal presumption that the patent cannot be invalidated based upon what is disclosed in the cited references.
Next, the Patent Examiners are listed, followed by the name of the patent attorney and/or the patent law firm that prosecuted the application.
The next item is  Abstract. This is a short description of the invention and is similar to the abstract of a scientific article. It permits searching of the subject matter of the patent.
Following the Abstract is a single line that indicates the number of claims in the patent and how many Drawing Sheets it contains.
The final item on the cover page is a Figure of the patent as representative of the invention. This Figure is also published in the Official Gazette (OG), a weekly government publication that provides information concerning patents and the U.S. Patent Office.
The Description and the Claims
A patent is made up of several parts, including a description that includes the drawings and the specification and a series of claims after the specification. The specification describes the invention and how to make and use it. Drawings are included if necessary to understand the invention. The claims specify what the actual invention is, that is, what is protected by the patent.
When reviewing a patent for any reason, non-patent professionals tend to jump immediately to the claims. The claims are thought to be the most important part of the patent. In certain circumstances, this is true. However in many, if not most, cases, it is the description of the invention that is of paramount importance.
When an inventor reviews a draft patent application, the description, not the claims, should be the focal point of the review. The description cannot be amended to include new matter after an application is filed. The claims can be amended after filing, but only to the extent that they claim what is described in the specification or shown in the drawings.
The description is also an important part of a patent when trying to determine if an invention is patentable in view of an existing patent, which is in studying a patent for its prior art disclosure. If an invention is described in a printed publication, such as a patent, more than one year before a patent application is filed for the invention, the invention will not be patentable. In reviewing a patent for its prior art effect, the specification and drawings should be the primary focus of study, not the claims.
The claims are analyzed to determine the scope of protection of a patent. This is important when deciding if your product infringes a competitors product or if the competitors product infringes your patent. The claims are also useful in figuring out how to "design around" a patent so that you do not infringe upon an existing patent. In the infringement analysis, the specification may also be reviewed, but it is primarily used to define any terms in the claims that may be unclear.
* A. Drawings.
The description contains two parts, a specification that describes the invention and the drawings. Because the drawings are part of the description, claims may be based on what is shown in the drawings, even if not described in the specification. Drawings are not always included as a part of the application. They are only used if necessary to understand the invention.
In patents claiming a mechanical apparatus, drawings are almost always present. The drawings show the various parts of the invention, each of which is assigned a reference number that is defined in the specification.
In biotechnology or pharmaceutical patents, drawings are not always present. For example, in a patent that claims a combination of ingredients used to make a pharmaceutical preparation and a method of making and using the combination of ingredients, a drawing would not be included because it is not necessary to understand the patent.
Drawings that may be encountered in biotechnology and pharmaceutical patents include gene or amino acid sequences, schematics of plasmids or recombination schemes, electrophoresis gels, and chemical formulas. Unlike mechanical drawings, the elements of these types of figures may lack identifying numerals.
* B. Specification.
The specification is the heart of the patent. It is the part of a patent that describes what the invention is, how to make it and how to use it. The specification also discusses the prior art and how the invention overcomes the problems that were unsolved before the invention. The specification contains the following parts.
1. Title. The title in the specification is the same as what is on the patent cover page.
2. Statement of Patent History. The first line of the patent discloses the existence of any prior applications that the present patent is based upon, and the fate of those applications, whether they were abandoned or eventually issued as patents.
3. Statement that the U.S. government has rights in the invention, if applicable. This occurs typically when the patented invention is a result of federally sponsored research.
4. Reference to a Sequence Listing, a table or a computer program listing appendix submitted on a compact disc and an incorporation by reference of the material on the compact disc, if applicable. This occurs when a computer program that is longer than 10 pages is part of the patent. Programs of this length are not printed with the patent but are available on microfiche.
5. Field of the Invention. This is a brief paragraph, typically one to two sentences long, describing the field to which the invention pertains.
6. Background of the Invention. In this section, the patent describes the problems that have not been solved by the prior art and that are solved by the patented invention. Prior art documents, such as patents or scientific articles, are discussed to show how previous efforts have failed to provide an answer to problems that are addressed in this patent.
7. Summary of the Invention. This section briefly summarizes the invention. It describes the invention in broad terms and how it overcomes the disadvantages of the prior art.
8. Brief Description of the Drawings. The figures are briefly described in broad terms, typically in one sentence, such as "Figure 1 shows a side view of the apparatus of the invention" or "Figure 2 shows the nucleotide sequence of gene X." The figures are described in greater detail in the next section of the patent.
9. Detailed Description of the Invention. This longest section of the patent describes the invention in detail. It describes each of the features of the invention and how to practice the invention (that is, how to make the invention), and how to use it. It also discloses what is known as the "best mode," which is the best way conceived by the inventor to practice the invention.
The detailed description of most patent applications in the biology and chemistry fields contains several examples. The examples describe in great detail how a biological or chemical invention is made. In a patent claiming a recombinant protein, there may be examples describing the growing of suitable microorganisms to be transformed, plasmid construction, isolation of DNA, transfection of the microorganisms, expression of the protein and isolation of the expressed protein.
Examples typically describe what an inventor has actually done in making and using the invention. Additionally, examples known as "prophetic examples" may be included that describe what has been conceived in the mind of the inventor as being a part of the invention, but which has not yet been performed.
The last paragraph of the specification typically is a statement that the invention is not limited to what is described, but also includes undescribed equivalents of the invention that is recited in the claims.
10. Abstract of the invention. The Abstract is published on the cover page of the patent.
Because the claims define the invention that is protected by the patent, they are in some ways the most important features of the patent. They provide guidance to competitors in steering clear of the patent. They indicate the scope and bounds of the patent so that a court can determine if the patent is infringed. The claims follow a set format with an unusual grammatical style that is sometimes difficult for non-patent professionals to understand.
The first part of the claim is the "preamble," which states in general terms what the invention relates to. Examples of preambles are "A bicycle," "A nucleic acid," "A pharmaceutical composition," "A method for treating arthritis," and "A device for accelerating wound healing." Generally, the wording of the preamble does not affect the scope of the patent protection.
Following the preamble is a "connector," which is usually either "comprising," "consisting of" or "consisting essentially of." The choice of connector is very important and has a tremendous impact on the breadth of the patent.
The term "comprising" in a claim means that the patent will be infringed by an article, device or a process that contains all of the features of the claimed device as described in the claim, even if the potential infringer contains additional features. As an example, if a claim recites a table comprising four legs and a top, the patent will be infringed by a table having five legs, or having four legs, a top and a shelf below the tabletop.
The term "consisting of" in a claim means that the patent will be infringed by anything that contains all of the features of the claimed invention, but will not be infringed if it contains additional features. A patent for a table consisting of four legs and a table top would not be infringed by a table having five legs or having a shelf below the tabletop. Because the term "consisting of" significantly narrows a patent claim, patent attorneys generally avoid it unless it is felt to be necessary in order to avoid very close prior art.
The term "consisting essentially of" is seen occasionally in patent claims in the biological and chemical fields. It means that a patent claim will be infringed if a potential infringer contains all the features of the claimed invention plus additional features that do not substantially change the nature of the invention. In the case of a pharmaceutical composition, the presence of an additive that enhances the effect of the patented composition, such as by increasing its shelf life or its potency, will infringe the patent. On the other hand, the presence of an additional ingredient that changes the nature of the composition, for example that makes it unsuitable for use as an acne medication but makes it suitable for increasing cardiac output, would not infringe the patent.
Following the connector is the body of the patent, describing the elements of the invention and how they are interrelated. These may be a series of mechanical parts and how they are put together. They may be a series of steps in a process to make or to use something. In order to infringe the patent, a device, composition of matter or process must contain every one of the listed elements, or their equivalents.
Claims come in two types: independent and dependent. Independent claims are those that can exist by themselves and typically begin with the word "A," for example, "A nucleotide sequence, comprising ..." Dependent claims refer to a previous claim, which can be an independent claim or another dependent claim. They contain all the features of the claim or claims that they depend from, plus one or more additional features. An example of a dependent claim is "The nucleotide sequence of claim 1, which further comprises..."
Generally, when determining whether a patent might be infringed, the first step is to determine if the potentially infringing article or process literally includes each of the features recited in the independent claims. Initially, there is often little reason to examine the dependent claims because, if the independent claims are not infringed (assuming that they contain the connector "comprising"), the dependent claims also will not be infringed. If there is no literal infringement of the claims, it will usually be necessary to obtain and review the prosecution history of the patent as it was examined in the Patent Office, referred to as the "file wrapper," to determine if there is infringement based on equivalents of the elements of the claims.
Contact Howard M. Eisenberg at (503) 227-5631, fax (503) 228-4373 or e-mail email@example.com.
This article originally appeared in the September 2003 issue of Recharger.