Table of Contents:

Introduction to the online version


Preface to the printed version

Copyright Overview

Software Copyright

Digital Copyright

Patent Overview

- History

- Why Patents?

- What Can Be Patented

- Getting A Utility Patent

- Novelty

- Anticipation And Obviousness

- Nature Of A Patent

- Infringement

Software Patents

Full treatise table of contents

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Chapter 4: An Overview of Patents

IV. Getting A Utility Patent

Unlike copyright or trade secrets, patent protection exists only after the filing of an application, its examination to determine compliance with the statutory requirements, and the issuance of a patent. Section 111 requires that the patent application consist of three parts – a specification, drawings (unless there is no meaningful drawing possible for the invention, which is unlikely in most cases), and an oath by the applicant stating that he believes that he is “the original and first inventor” of the invention. {FN20: 35 U.S.C. §111}

Although a written application must be submitted, it is generally not necessary to submit a working model. At one time, the submission of a model was required, but space considerations and the desirability of publishing the granted patents led to the dropping of the model requirement. Now, about the only time a model is required is when there is some question whether the invention will actually work, such as when it appears to be a perpetual motion machine. As stated in Section 114:

   The Commissioner may require the applicant to furnish a model of convenient size to exhibit advantageously the several parts of his invention.

   When the invention relates to a composition of matter, the Commissioner may require the applicant to furnish specimens or ingredients for the purpose of inspection or experiment. {FN21: 35 U.S.C. §114}

In fact, it is not even necessary to have a working model for the invention if the invention can be described in the application in such full and complete terms that somebody skilled in the art of the invention can make and use it from the application description. While this is seldom the case for a mechanical or chemical invention, for software-based inventions it is often possible to determine that the invention will function properly and describe it in detail without doing a complete implementation of the software. This is referred to as a “constructive reduction to practice,” as opposed to the “actual reduction to practice” that occurs when a prototype of the invention is constructed and tested to determine that it works as intended.

Section 112, first and second paragraphs, states the requirements for the specification:

   The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.

   The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. {FN22: 35 U.S.C. §112}

IV.A. The Description

The first paragraph is the description requirement. The description of the invention teaches how to make and use it and includes a brief abstract of the invention. The bargain in the granting of the patent is that the public receive a complete description of how to make and use the invention, so they can practice the invention without undo experimentation after the patent expires, or can understand it so they can develop improvements. The description must detail the best way that the inventor knows at the time of the application for making and using the invention (often called the “best mode” or “preferred embodiment” of the invention).

Sometimes an applicant includes only a description of the preferred embodiment in the specification, perhaps believing that other ways of practicing the invention are inferior and that their description should be unnecessary as long as the best mode has been described. This can cause a problem if the patent is litigated, because the court may see the patent covering only the single embodiment that was described, rather than a more general invention. To avoid this, an applicant should indicate alternative embodiments for components of the invention, even if these embodiments are not as good as the primary one being described.

Because patents are often the first description of a new technology, and there may not be accepted terms for key aspects of an invention, an applicant is allowed to use his or her own terms for aspects of the invention as long as they are defined in the specification. This is often stated as “A patentee can act as his own lexicographer.” These definitions should be clearly stated, especially if the term has a generally-accepted meaning that differs from the usage in the patent.

It is important that the same name be used for something throughout the patent, and particularly in both the description and the claims. This is not the place for using synonyms or shortened descriptions, lest there be confusion about the meaning of a term in the claims when they are being interpreted in litigation. If you call something a “left-handed framus” in the claims, make sure that wherever it is mentioned in the description it is also called a “left-handed framus,” not just a framus or a similar term like a “sinister framus,” even though most people in the art of the invention use the terms interchangeably.

IV.B. Claims

The claims define those aspects of the invention that are protected by the patent. It is not possible to determine what is protected by the patent from the title, abstract, or description. You must read the claims. But to properly interpret the claims, you must read them in light of the description and any statements made during the prosecution or examination of the patent application.

Almost without exception, a claim starts with a “preamble” that introduces the nature of the claimed invention and its environment, a “transitional term,” and one or more or “limitations” or “claim elements.” A claim is always in a form that completes a sentence starting with “I claim” or “We claim” or “What is claimed is” or some similar phrase. It is never proper for a claim to be more than one sentence.

A special word that is commonly used in claims is “said.” Proper claim drafting requires that each aspect of a claim, such as a part of the claimed device, must be clearly recited before it can be used in a following claim limitation. For example, you must recite “a pencil comprising an eraser at one end” before you can talk about “the pencil’s eraser.” After introducing “an eraser,” you refer to it as “the eraser” or, more traditionally, “said eraser.” If there are two different erasers that are aspects of the claim, then you must always make it clear which one you are discussing, by using language such as “said eraser at said large end of said pencil,” if you have previously indicated that the pencil has a large end, or “said second eraser,” if you have designated each eraser by an ordinal.

Another special word in a claim is “plurality.” It means two or more and is used when it is necessary to differentiate the invention in the claim from prior art that has only a single instance of something. For example, if you claim “a plurality of computer processors,” the claim will cover systems with two or more processors, but not those with a single processor. One could achieve the same coverage by claiming a system with “two computer processors,” since a system with three or more processors clearly contains a system with two processors, but it is possible that the claim could be misconstrued in litigation as covering only two-processor systems, so “a plurality” or “at least two” is a better choice.

IV.B.1. When a Claim “Reads On” Something

The most important concept in understanding a claim is whether the claim “reads on” something. A claim reads on a physical object or a process when all the elements of the claim are components of that object or process. A claim also reads on a description of an object or process when all elements of the claim are described in the publication. (For simplicity, we’ll talk about a claim reading on a thing, where the thing can be a physical object, process, or description of an object or process, as appropriate.) Because the presence of an element in a claim limits the scope of that claim to things having that element as a component, claim elements are often also called “claim limitations.”

If a thing has components in addition to those of the claim limitations, it is necessary to consider the transitional term to determine if the claim reads on the thing. The most common transition term, “comprising,” means that the claim reads on the thing if all the elements of the claim are components of the thing, regardless of what other components may be present in the thing. (Sometimes “including” or “having” is used instead of “comprising.”) That means that the claim limitation “comprising A, B, and C” reads on every thing that has A, B, and C, even if the thing also has D through Z. A claim to a new type of screw using “comprising” as its transition term would read on a complete automobile if that screw were present anywhere as part of the car.

If a claim contains elements A and B, that claim does not read on a thing with just an A, an A combined with anything that is not a B, just a B, or a B combined with anything that is not an A. In other words, when the transition term “comprising” is used, a claim reads on any thing whose components are a superset (or are identical) to the elements of the claim.

One has to be careful when using the conjunction “or” with two claim elements. If a claim were written as “comprising A, B, and C or D” it would read on either a thing with A, B, and C or a thing with A, B, or D. That would make the claim invalid if there were something with A, B, or C in the prior art even if something with A, B, or D was novel. And unless there is a strong relationship between C and D, the patent office frowns on such claims.

Similarly, a claim like “A, B, but not C” might raise questions if C were not something that is a part of A and B, so that its exclusion (presumably because the only prior art with A and B also always includes C). The claim must still distinctly describe what is claimed, not what is not claimed.

There are two more restrictive transitional terms. The claim “consists of A and B” reads on things that have only A and B as their components, and absolutely nothing else. The claim “consisting essentially of A and B” reads on things that have A, B, and some other inconsequential components, such as noncritical impurities in a composition of matter. Because transition terms severely limit the scope of their claims, they are uncommon except in chemical claims where it is necessary to limit the claim to a particular compound.

It is important that you fully understand the concept of a claim reading on something. It is perhaps the most important concept in all of patent law. As we will see, a claim must not read on the prior art or that claim is invalid. And if a claim reads on something that is not prior art, that something infringes the patent.

IV.B.2. The Steps of a Method

It is not necessary to include every step of the method in the claims, since claims are not a description of how to implement the method. But the claims should include all the steps necessary to describe the claimed method.

Generally, there is no requirement that the steps of the claimed method be executed in the order specified in the claim for infringement to occur. All that is required is that, at some time, the infringing act must perform every step in the claim. However, where an order is specified, either explicitly (by using a connective like “and then” between two steps) or implicitly (as when one step requires information produced by another step), then those steps must be executed in the specified order. Similarly, if there is no particular ordering of the steps of a method desired, saying “comprising the following steps, in any order,” rather than simply “comprising,” will make that intention clear.

If only one embodiment of the claimed invention is described, or if all the embodiments show particular steps always being performed in a certain order, there is the possibility that the claim may be construed as requiring that particular order. If other orders are possible, examples should be briefly mentioned in the description.

IV.B.3. The Preamble

There has been a great deal of debate on whether the preamble of a claim adds limitations to a claim or simply provides the background for the claim. Does the claim “a widget, comprising A, B, and C” read on a non-widget that nevertheless has A, B, and C? It depends on whether the preamble is necessary to give meaning to the claim, and whether it was treated as a limitation during the examination of the patent application.

The best thing to do when writing a claim is to include in a preamble only what is necessary to provide an antecedent basis for a term used later in the claim, but which is not a part of the invention as being formally claimed. For example, if you are claiming a computer method for manipulating a data structure on a disk, you can introduce the disk in the preamble (“a method operating on a disk”) so that you can use it later when describing a step of the method (“storing information on said disk”).

Many claim drafters include in the preamble a short description of the purpose of the invention (“a method for secure communications”) or the name of what is being patented (“a widget”). This is not a good idea, since it might be read as a limitation. Instead, just say “a method” or “an article of manufacture” or some similar phrase that cannot possibly be interpreted as a limitation.

IV.B.4. Dependent and Independent Claims

There are two types of claims – independent claims and dependent claims. These are described in the third and fourth paragraphs of Section 112:

   A claim may be written in independent or, if the nature of the case admits, in dependent or multiple dependent form.

   Subject to the following paragraph, a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers. {FN23: 35 U.S.C. §112}

A dependent claim can be recognized because it starts with something like “a widget as in claim 1, further comprising D.” If claim 1 were for “a widget, comprising A, B, and C,” then that dependent claim would be identical to an independent claim reading “a widget, comprising A, B, C, and D.” (Think of a dependent claim as a macro, which replaces the introductory phrase with all the text of the claim on which it depends.)

The Patent Office likes dependent claims because they do not have to be separately examined for validity if the claim on which they are based is valid. That is because they always contain more limitations than their parent claim and can’t read on prior art if their parent claim doesn’t. (In the example above, if the prior art does not have widgets with A, B, and C, it certainly doesn’t have widgets with A, B, C, and D.) All the examiner needs to do is make sure they are in the proper form. Because of this, the Patent Office charges considerably less for examining a dependent claim.

Dependent claims provide a fallback position in case a claim is later found invalid by a court. For example, consider the independent and dependent claims above. If the independent claim reads on prior art, but the dependent claim doesn’t, then the dependent claim survives and is treated as if it were written in full independent form. (It doesn’t depend on the parent claim for its validity, just for the limitation to be included.)

Sometimes claim drafters will use dependent claims to indicate particular species of a general term. For example, if the parent claim has as an element “a computer network,” then a dependent claim may state “where said computer network is an Ethernet” and another dependent claim may state “where said computer network is a token ring.” Such dependent claims are often worthless as a backup position, however, if it would be obvious how to take a prior art teaching showing one species and implement the other species. For example, if a patent had claims like those described in this paragraph and prior art was discovered showing a token ring network (along with all the other elements of the claim), then the parent claim for a network in general, and the dependent claim for a token ring network, would both be invalid. But so would the dependent claim of an Ethernet, if it were obvious how to apply the teaching of a token ring network to an Ethernet.

A multiple dependent claim is something like “a widget as in claim 5 or claim 10, further comprising X.” Because of the difficulty in checking that a multiple dependent claim, the Patent Office charges a surcharge for examining such a claim. For that reason, they are not commonly used. The fifth paragraph of Section 112 describes the special rules for multiple dependent claims.

IV.B.5. Other Claim Forms

It is generally improper to have a claim limitation that states alternatives. An exception to this is a “Markush claim,” named after the applicant who first received approval to use such a claim. A Markush claim contains a limitation like “an R, wherein R is selected from the group consisting of A, B, C, and D” or similar language. There must be some property that unites the alternatives in a Markush claim. Not surprisingly, this type of claim is used primarily in chemical patents, where the alternatives are chemical elements or compounds that share a necessary property, such as being metals or rare earths.

Another special claim form is the “Jepson claim,” where the preamble describes the old parts of the invention, and the limitations are drawn only to the improvement over the prior art. It is generally written like “a widget having A, B, and C, the improvement comprising D and E.” The Patent Office prefers all claims to be written in Jepson format, because it makes it clear what the applicant feels is novel about the invention, but it is seldom used in practice. That is because if A, B, and C of the example are not really in the prior art, they will still be treated as prior art because the claim stated that they were.

IV.B.6. Means Plus Function Elements

Sometimes there is not a collective term for describing a particular limitation. This is addressed by the sixth, and last, paragraph of Section 112:

   An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof. {FN24: 35 U.S.C. §112}

This was added to the patent laws to overturn a Supreme Court decision {FN25: Halliburton Oil Well Cementing v. Walker, 329 U.S. 1, 71 USPQ 175 (1946)} that said that elements couldn’t be described by the function they perform. Because such claim elements are generally written as “means for <some function>,” they are generally referred to as “means-plus-function” or “means-for” claim elements.

It is important to note that the sixth paragraph makes it clear that the claim element does not cover all ways of performing the function, but only those described in the specification and their equivalents. For example, if the limitation is “means for fastening A to B” and the specification discloses that it is important that the fastening occur when the side of B opposite A is inaccessible and discloses nails and screws, then a bolt-and-nut combination would not be a means for fastening A to B, but a contact adhesive might be if it performs the same function as a nail or a screw.

Many people mistakenly think that a means-for claim element is very broad, but that may not be the case. It may be, instead, very narrow, depending on what was disclosed in the specification. The specification, for example, may disclose only one structure for performing the function, in which case the claim element covers only that disclosed structure and its equivalents. More important, the specification may not disclose sufficient structure, in which case the claim is invalid because it does not provide a definite indication of what is being claimed.

Because the sixth paragraph talks about “an element in a claim for a combination,” it is improper to have a single-element claim with that element written in means-for form. Such a claim attempts to claim all ways of doing the specified operation, although it would be limited to the means described in the specification.

During claim interpretation during litigation of a patent, one of the jobs for the court will be to determine the structure that corresponds to the “means for” in a claim. Sometimes this is not easy, since the description of the means is spread throughout the description and is not clearly indicated. To aid the court (and to make sure its determination matches your intentions), clearly indicate in the description what you consider the means for performing a particular function, including any alternative means that you have briefly described.

During the examination of a patent application, the Patent Office used to consider the element as covering all reasonable means for performing the function rather than just those disclosed in the specification. This saved it from locating the descriptions in the specification, which could be a problem if it wasn’t clear where something was being described (for example, if it was described in multiple places). That practice came to an end when the Court of Appeals for the Federal Circuit made it clear, in In re Donaldson, {FN26: 16 F.3d 1189, 29 USPQ2d 1845 (Fed. Cir. 1994)} that the sixth paragraph’s requirement for the scope of the means-plus-function claim element had to be followed even during patent examination. There is still a tendency, however, for examiners to read the means-plus-function limitation as covering all reasonable means, but to limit its scope when the applicant points out that a particular implementation isn’t within the scope of the means-plus-function claim element. That way, the fact that the claim doesn’t cover that particular implementation is on the record and the applicant can’t later say that it is within the scope of the claim.

Means-plus-function claim elements are frequently used with claims for software-based inventions, since the claim covers the hardware that implements a particular function, whether it is special-purpose logic or a general-purpose digital computer programmed to perform the specified function. But again, it covers only the means described in the specification and their equivalents.

A less-clear concept also found in the sixth paragraph of Section 112 is that of a functional step, although such claim language is common in process patents and particularly in patents on software-based processes. There are few court decisions regarding “step-plus-function” claim elements; Judge Rader’s concurrence in Seal-Flex Inc. v. Athletic Track and Court Construction {FN27: 172 F.3d 836, 50 USPQ2d 1225 (Fed. Cir. 1999)} provides the best discussion. There, he draws the distinction between a claim element that recites an act, which would not be in step-plus-function form, and one that recited a function to be performed, which would be in step-plus-function form.

The distinction is subtle. An example of such a functional step limitation might be “computing a checksum for the packet,” which would cover the ways of computing a checksum for a packet detailed in the description and their equivalents. In contrast, the step “computing a checksum for the packet using a table-lookup technique” specifies the act to be performed and therefore isn’t in step-plus-function form.

Next section: Novelty

Copyright © 2002, Lee A. Hollaar. See information regarding permitted usage.