Prosecution Related Issues
Prosecution History Estoppel

Patent Infringement

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Background of the Invention

This section should include a statement of the field of endeavor to which the invention pertains. This section may also include a paraphrasing of the applicable US patent Classification Definitions or the subject matter of the claimed invention. In the past, this part of this section may have been titled "Field of Invention" or "Technical Field."

This section should also contain a description of information known to you, including references to specific documents, which are related to your invention. It should contain, if applicable, references to specific problems involved in the prior art (or state of technology) which your invention is drawn toward. In the past, this section may have been titled "Description of the Related Art" or "Description of Prior Art."

Brief Summary of the Invention

This section should present the substance or general idea of the claimed invention in summarized form. The summary may point out the advantages of the invention and how it solves previously existing problems, preferably those problems identified in the BACKGROUND OF THE INVENTION. A statement of the object of the invention may also be included.

Brief Description of the Several Views of the Drawing

Where there are drawings, you must include a listing of all figures by number (e.g., Figure 1A) and with corresponding statements explaining what each figure depicts.

Detailed Description of the Invention

In this section, the invention must be explained along with the process of making and using the invention in full, clear, concise, and exact terms. This section should distinguish the invention from other inventions and from what is old and describe completely the process, machine, manufacture, composition of matter, or improvement invented. In the case of an improvement, the description should be confined to the specific improvement and to the parts that necessarily cooperate with it or which are necessary to completely understand the invention.

It is required that the description be sufficient so that any person of ordinary skill in the pertinent art, science, or area could make and use the invention without extensive experimentation. The best mode contemplated by you of carrying out your invention must be set forth in the description. Each element in the drawings should be mentioned in the description. This section has often, in the past, been titled "Description of the Preferred Embodiment."

Claim or Claims

The claim or claims must particularly point out and distinctly claim the subject matter which you regard as the invention. The claims define the scope of the protection of the patent. Whether a patent will be granted is determined, in large measure, by the choice of wording of the claims.

A nonprovisional application for a utility patent must contain at least one claim. The claim or claims section must begin on a separate sheet. If there are several claims, they shall be numbered consecutively in Arabic numerals, with the least restrictive claim presented as claim number 1.

The claims section must begin with a statement such as "What I claim as my invention is: . . ." or "I (We) claim: . . ." followed by the recitation of the particular matter which you regard as your invention.

One or more claims may be presented in dependent form, referring back to and further limiting another claim or claims in the same application. All dependent claims should be grouped together with the claim or claims to which they refer to the extent practicable. Any dependent claim that refers to more than one other claim ("a multiple dependent claim") shall refer to such other claims in the alternative only. Each claim should be a single sentence, and where a claim sets forth a number of elements or steps, each element or step of the claim should be separated by a line indentation.

The fee required to be submitted with a nonprovisional utility patent application is, in part, determined by the number of claims, independent claims, and dependent claims.

Each element in an independent claim (i.e., a claim that does not refer to another claim) does not have to be novel, but at least one claim element (i.e., clause or limitation), must be novel. Generally, claim limitations that are not novel should be included if it is technically accurate and necessary to carry out the required function/structure of at least the most basic application of the invention. Novelty is evaluated by considering all limitations within a given claim together. It is common to name elements/functions in a claim that are not novel, but are necessary to describe how the novel aspects of your invention cooperate with the known elements.

Each element in a dependent claim (i.e., a claim that does refer to another claim) does not have to be novel, and should be included if it is technically accurate and a commercially viable function/structure/instance that is either novel or, if not novel, that a competitor might carry out in combination with the root claims. Novelty is evaluated by evaluation of the independent claim limitations together with the dependent claim limitations.

Abstract of the Disclosure

The purpose of the abstract is to enable the USPTO and the public to determine quickly the nature of the technical disclosures of your invention. The abstract points out what is new in the art to which your invention pertains. It should be in narrative form and generally limited to a single paragraph, and it must begin on a separate page. An abstract should not be longer than 150 words.

Information Disclosure Statement

The USPTO requires the filing of an Information Disclosure Statement (IDS) with copies of all relevant publications (patents or otherwise) known to the inventor. The IDS is usually filed after receiving the official filing receipt from the USPTO, about three months after filing the application. Attorneys generally charge an IDS preparation fee, and there might be additional fees from document suppliers, if you cannot supply a copy of a reference and your practitioner needs to procure it elsewhere. It is usually recommended that you provide your practitioner with copies of all publications you know about before they file your application (ideally, before the first draft is prepared). Note that if you become aware of any references which are relevant to patentability during the pendency of the patent, for example if a foreign patent office cites patents against a foreign counterpart of the US application, a Supplemental IDS should be filed with the references.

Prosecution Related Issues

There are many actions that occur during the prosecution of a patent application that can significantly affect the resulting patent after being granted. Many of these issues show up during patent infringement litigation in the courts. What follows, is a highlight of some of these pertinent issues.

A skilled patent drafter should attempt to foresee the limiting potential of a claim limitation. Sometimes subtlety of language or complexity of the technology, or any subsequent change in the state of the art, such as later-developed technology, may, however, obfuscated the significance of this limitation at the time of its incorporation into the claim. There is an opportunity to broaden patent protection by seeking claims with fewer structural encumbrances or method steps. If the claims are drawn too narrow, then patent scope may not be recovered by what is known as the doctrine of equivalents. The patentee has an opportunity to negotiate broader claims up to two years after patent issuance, where afterwards, it is the patentee who must bear the cost of its failure to seek protection for any foreseeable alteration of its claimed structures or steps.

The claims define the scope of protection for a patent afforded to the actual inventor. Patent law requires the applicant to swear, or affirm, that he believes himself to be the true inventor of the art, machine, or improvement, for which he asks for a patent; and further that he shall deliver a written description of his invention, in such full, clear, and exact terms, that any person, acquainted with the art, may know how to construct and use the same. The reason for this is to guard the public against unintentional infringements of the patent, and to enable the public to make an improvement that does not infringe your patent. When an accused device possess every limitation of a claim in your patent, then that device or process has comitted literal infringement of your patent. However, the language in the patent claims may not capture every nuance of the invention or describe with complete precision the range of its novelty. If patents were always interpreted by their literal terms, their value would be greatly diminished. Unimportant and insubstantial substitutes for certain elements could defeat the patent, and its value to inventors could be destroyed by simple acts of copying. For this reason, the clearest rule of patent interpretation, literalism, may conserve judicial resources but is not necessarily the most efficient rule. The scope of a patent is not limited to its literal terms but instead embraces all equivalents to the claims described. In this way, a balance between the two competing policies behind the enforcement of patent rights: (1) to protect the inventor’s right to exclude others who might steal the product of his work by making equivalent modifications, and (2) to provide clear notice to the public of the invention’s boundaries.

In generic terms: in determining the patentably of your your invention, the Patent Office must consider utility, novelty, obviousness, and so called "secondary considerations." Generally, if your product or process does something useful that a "close" one does not, then your product would logically be novel. You must then question if the additional features or functions that you are claiming as novel would have been obvious to do for an average person skilled in the field of your invention. If the novelty is clearly not obvious to an average skilled artisan, then your invention would very likely be patentable, all other things being equal. If your invention's novelty is questionably obvious, then the fallback argument, although some what weaker, is to set forth any secondary consideration that relate to the commercial viability of your product over the others in question. For the more complicated case where your invention is questionably obvious, read on...

Patent law is designed to serve the small inventor as well as the giant research organization. One fact to keep in mind is that most, if not all, inventions are combinations and mostly of old elements. Therefore an examiner may often find every element of a claimed invention in the prior art. If identification of each claimed element in the prior art were sufficient to reject patentability of your invention, then very few patents would ever issue. Patent examiners are not allowed to reject patents solely by finding your claimed elements in the prior art. If that were allowed it would permit an examiner to use the claimed invention itself as a blueprint for piecing together elements in the prior art to defeat the patentability of patents. The courts have said such an approach would be an illogical and inappropriate process by which to determine patentability.

You should also be aware that it is not a requirement of patentability that an inventor correctly set forth, or even know, how or why the invention works.

Generally, the claimed invention must be considered as a whole, and the question is whether there is something in the prior art as a whole to suggest the desirability, and thus the obviousness, of making the combination. When determining the patentability of a claimed invention which combines two known elements, the question is whether there is something in the prior art as a whole to suggest the desirability, and thus the obviousness, of making the combination.

To prevent the use of hindsight based on the invention (i.e., viewing the prior-art in terms of what your invention or the art after your filing date teaches) to defeat patentability of the invention, courts require the examiner to show a motivation to combine the references that create the case of obviousness. In other words, the examiner must show reasons that the skilled artisan, confronted with the same problems as the inventor and with no knowledge of the claimed invention, would select the elements from the cited prior art references for combination in the manner claimed.

Courts have identified three possible sources for a motivation to combine references: the nature of the problem to be solved, the teachings of the prior art, and the knowledge of persons of ordinary skill in the art. It is not allowed for the examiner to just rely on the high level of skill in the art to overcome the differences between the claimed invention and the selected elements in the references, and provide the necessary motivation.

Instead, the examiner, if rejecting your claim based on obviousness, must explain what specific understanding or technological principle within the knowledge of one of ordinary skill in the art would have suggested the combination. Otherwise, if a rote piecing together of prior-art elements could suffice to supply a motivation to combine, the more sophisticated scientific fields would rarely, if ever, experience a patentable technical advance. That is, for example, in complex scientific fields, the examiner could routinely identify the prior art elements in an application, invoke the lofty level of skill, and rest its case for rejection. To counter this potential weakness in the obviousness construct, the suggestion to combine requirement stands as a critical safeguard against hindsight analysis and rote application of the legal test for obviousness.

Obviousness is ultimately a question of law that rests on underlying factual inquiries including: (1) the scope and content of the prior art; (2) the level of ordinary skill in the art; (3) the differences between the claimed invention and the prior art; and (4) objective considerations of nonobviousness. Objective considerations such as failure by others to solve the problem and copying may often be the strongest evidence of nonobviousness.

This objective evidence of nonobviousness includes so-called "secondary considerations" such as copying, long felt but unsolved need, failure of others, commercial success, unexpected results created by the claimed invention, unexpected properties of the claimed invention, licenses showing industry respect for the invention, and skepticism of skilled artisans before the invention

The so-called "secondary considerations" provide evidence of how the patented device is viewed by the interested public: not the inventor, but persons concerned with the product in the objective arena of the marketplace.

Prosecution History Estoppels

Traditionally, the doctrine of prosecution history estoppels has been defined as an equitable tool for determining the scope of patent claims. The doctrine bars the patentee from construing its claims in a way that would resurrect subject matter previously surrendered during prosecution of the patent application, and thus prevents a patentee from enforcing its claims against otherwise legally equivalent structures if those structures were excluded by claim limitations added to avoid prior art. The traditional view that depending upon the nature and purpose of an amendment, the doctrine may have a limiting effect within a spectrum ranging from great to small to zero was recently changed by the federal circuit. Accordingly, all amendments made for the purpose of patentability are now deemed to have the effect of depriving the inventor of a claim interpretation that includes equivalent structures.

Generally, an amendment that narrows the scope of a claim for any reason related to the statutory requirements of a patent will give rise to prosecution history estoppel with respect to the amended claim element. That is, while the patentee has the right to appeal, his decision to forgo an appeal and submit an amended claim is taken as a concession that the invention as patented does not reach as far as the original claim. That is, where the original application once embraced the purported equivalent but the patentee narrowed his claims to obtain the patent or to protect its validity, the patentee cannot assert that he lacked the words to describe the subject matter in question. The doctrine of equivalents is premised on language's inability to capture the innovation, but a prior application describing the precise element at issue undercuts that premise. In that instance the prosecution history has established that the inventor turned his attention to the subject matter in question, knew the words for both the broader and narrower claim, and affirmatively chose the latter.

Estoppel general arises when an amendment is made to secure the patent and the amendment narrows the patent's scope. If a §112 amendment is truly cosmetic, then it would not narrow the patent's scope or raise an estoppel. On the other hand, if a §112 amendment is necessary and narrows the patent's scope -- even if only for the purpose of better description - estoppel may apply. A patentee who narrows a claim as a condition for obtaining a patent disavows his claim to the broader subject matter, whether the amendment was made to avoid the prior art or to comply with §112. The courts regard the patentee as having conceded an inability to claim the broader subject matter or at least as having abandoned his right to appeal a rejection. In either case estoppel may apply, especially when the patentee is unable to explain the reason for amendment, estoppel not only applies but also bars the application of the doctrine of equivalents as to that element. Case law makes clear that the patentee should bear the burden of showing that the amendment does not surrender the particular equivalent in question, and that the patentee, as the author of the claim language, may be expected to draft claims encompassing readily known equivalents. Hence, a patentee's decision to narrow his claims through amendment may be presumed to be a general disclaimer of the territory between the original claim and the amended claim.

By amending the application, the inventor is deemed to concede that the patent does not extend as far as the original claim. It does not follow, however, that the amended claim becomes so perfect in its description that no one could devise an equivalent. After amendment, as before, language remains an imperfect fit for invention. The narrowing amendment may demonstrate what the claim is not; but it may still fail to capture precisely what the claim is. Case law makes clear, however, that there is no reason why a narrowing amendment should be deemed to relinquish equivalents unforeseeable at the time of the amendment and beyond a fair interpretation of what was surrendered. Nor is there any call to foreclose claims of equivalence for aspects of the invention that have only a peripheral relation to the reason the amendment was submitted, or if there was some other reason suggesting that the patentee could not reasonably be expected to have described the insubstantial substitute in question. In such cases the patentee can overcome the presumption that prosecution history estoppel bars a finding of equivalence.

Canceling claims and replacing with narrower versions may create estoppel as well. For example, consider the case where certain rejected claims were never amended, but instead canceled and replaced with claims containing a more narrow scope, which are later issued with a patent. In this example, the courts will not discern any legally significant difference between canceling a claim having a broad limitation and replacing it with a claim having a narrower limitation, and amending a claim to narrow a limitation, since to do so "would place form over substance and would undermine the rules governing prosecution history estoppel laid out in Festo by allowing patent applicants simply to cancel and replace claims for reasons of patentability rather than to amend them". Thus, canceling and replacing claims is considered analogous to amending them.

The presumption prosecution history estoppel is not just a complete bar by another name. Rather, it reflects the fact that the interpretation of the patent must begin with its literal claims, and the prosecution history is relevant to construing those claims. When the patentee has chosen to narrow a claim, courts may presume the amended text was composed with awareness of this rule and that the territory surrendered is not an equivalent of the territory claimed. In those instances, however, the patentee still might rebut the presumption that estoppel bars a claim of equivalence. The patentee must show that at the time of the amendment one skilled in the art could not reasonably be expected to have drafted a claim that would have literally encompassed the alleged equivalent.

The courts reason that explicit arguments made during prosecution to overcome prior art can lead to narrow claim interpretations makes sense, because the public has a right to rely on such definitive statements made during prosecution as public notice, which is regarded as an important function of the patent prosecution process. By distinguishing the claimed invention over the prior art, an applicant is explicitly indicating what the claims do not cover. Therefore, a patentee, after relinquishing subject matter to distinguish a prior art reference asserted by the PTO during prosecution, cannot during subsequent litigation escape reliance by the defendant upon this unambiguous surrender of subject matter. Accordingly, claims may not be construed one way in order to obtain their allowance and in a different way against accused infringers.

For information on infringement of a patent, click on one of the following topics:

nonprovisional, utility patent information

Parts of a nonprovisional, Utility Patent Specification

Background of the Invention
Brief Summary of the Invention
Brief Description of the Several Views of the Drawing
Detailed Description of the Invention
Claim or Claims
Abstract of the Disclosure
Information Disclosure Statement

Prosecution Related Issues
Prosecution History Estoppel

Patent Infringement

Document Maintenance

nonprovisional, utility patent information

Parts of a nonprovisional, Utility Patent Specification

Background of the Invention Brief Summary of the Invention Brief Description of the Several Views of the Drawing Detailed Description of the Invention Claim or Claims Abstract of the Disclosure Information Disclosure Statement

Prosecution Related Issues Prosecution History Estoppel

Patent Infringement

Document Maintenance

Background of the Invention
Brief Summary of the Invention
Brief Description of the Several Views of the Drawing
Detailed Description of the Invention
Claim or Claims
Abstract of the Disclosure
Information Disclosure Statement

Prosecution Related Issues
Prosecution History Estoppel