Patents are an important part of an intellectual property strategy. This post discusses the process of obtaining and defending a patent.There are other posts that discuss strategic uses of patents.

see: Intellectual Property Patent Strategy

This discussion of patents is based on U.S. law, which is similar in many respects to patent law in other countries. This is also meant as an overview to guide strategic thinking about patents. Consult a patent attorney for details.

A patent is the right to exclude others from using your ideas in exchange for public disclosure of those ideas. This right of exclusion is limited to 20 years after the filing for the patent. For a patent to be valid, it must be original and non-obvious. These two criteria are important and are the basis for obtaining and defending a patent. The original requirement is so that patents protect inventors. What society wants is to reward the creation of new knowledge. The invention must not only be original but non-obvious. The test is “obvious to someone reasonably skilled in the art.” For example, if you have a new web technology it must be non-obvious to other web programmers at the time you filed for the patent. The fact that it was non-obvious to web users does not matter because they are not skilled in the art of web programming. The time of filing also matters. If all web programmers understand your approach today, that does not matter. It is only obvious if most web programmers understood your approach at the time you filed for the patent.

Patenting process

This is somewhat of a simplification, but there are generally four steps to the patent process.

  • Provisional application (optional)
  • Full application
  • Granting the patent
  • Enforcement


Figure 1 – Patent process

Your optional provisional filing will describe certain parts of your invention. The provisional filing does not restrict your full patent filing but it does establish a filing date. Anything in your full filing what does not appear in your provisional filing will have the date of the full filing, not the date of the provisional. Your full filing will contain claims of what you actually claim to have invented. It is these claims that define your intellectual property. Some time later after several rounds between your lawyers and the patent office, your patent is granted (or rejected). At some point in the future when someone uses your technology, you have a case for infringement of your patent. This is where you attempt to enforce your claims for economic advantage. This is also where your patent really gets tested.

Provisional application

A provisional application is optional, but it does provide you with some opportunities. A provisional application is much less formal than a full patent application. This is generally a document that describes all of your ideas. The purpose of the provisional is to set an official date for the start of your patent protection. Any ideas that you set out in a provisional application are considered yours as of the date of filing. For that date to be good you need to file a full application within one year. If you fail to file within one year, you do not lose your right to file because a provisional application is not a public disclosure. All you lose is the filing date of your provisional application. The filing date is important when later enforcing your patent.

A big advantage of a provisional application is that the costs are relatively low. It only needs a relatively brief look by a patent attorney to make certain that your coverage is good and your terms well defined.

There are two big reasons for filing a provisional application. The first is to establish an earlier filing date for your claims. In the U.S. and most jurisdictions, the patent goes to the first one to file on an invention, not the first one to have invented the ideas. This makes your filing date very important. Anything after the filing date is an infringement of your patent.

The second reason for filing a provisional application is to have a year of coverage without much cost. This allows you to more freely discuss your technology without losing your patent rights. You have a year to shop the ideas around before you commit to the costs of a full patent filing. If you discuss your ideas publicly, be careful to get your full filing done before the year expires. If you do not, then your own public discussion of the ideas may make your patent invalid.

If you do not discuss your work publicly, you can file a new provisional at a later date and capture a later filing data. You can also file many provisionals. What matters ultimately is the full patent application. The purpose of provisional disclosures is the legally establish a filing date.

Full patent application

Of most interest in the software world are utility patents. There are also design patents that are used much less often and plant patents which we never use. The full patent application is the definition of what you invented. You have three tasks in preparing this application. The first is to clearly describe what you invented and how your invention works.  The second is to clearly define what you claim to invented and any terms in those claims. The third is to identify prior work that may relate to your claims.

You should never file a full patent application without the help of a patent attorney. The use of words is critical and you need someone trained to phrase things correctly. However, you also need to invest the time to learn from your patent attorney and watch carefully what is said in the application. Remember the attorney knows the law but you know your invention. It takes both minds to make a good patent. This also the point where patenting costs go from mere hundreds of dollars to thousands.

A patent has two basic parts: 1) the specification where you disclose your invention, define your terms and address any prior work, 2) the claims where you define your invention.


An important reason for granting you a patent is to induce you to disclose your ideas and techniques so that others can learn from them. You do not need to disclose all possible ways to practice your patent. You probably do not know all possible ways. You must disclose the best way that you currently know. Keeping your best stuff secret is heavily frowned upon when defending your patent. The disclosure goes in the specification portion of your patent application.


At the end of every patent is a list of claims. This is where you clearly define exactly what you claim to have invented. There are independent claims (they stand on their own) and dependent claims (extensions of other claims in the same patent). A claim is a legal definition of an invention. The claims are what will be contested when you file an infringement case.

In the claims you will use a variety of terms to specify what you invented. Much of a patent case will revolve around what these terms really mean. In seeking a definition, the court will first look at your specification. If no definition is found there, they will look at other books or publications that existed at the time of filing. You do not want the court or your opponents to make the choice of what your words mean. Define every important term somewhere in the specification. Even if your definition is unique, for the purpose of this patent, the definition is whatever the specification says it is. Take control of your terms and provide clear definitions. Do not leave it to the court to figure out what you meant. You will need to work with your attorney on this because they generally do not understand your technology.

prior work

One of the ways to contest a patent is to show that it is not original because some piece of work, prior to your filing, already contains your invention. A good defense against this is to discuss in your specification, all of the prior work that you think might relate. If you provide clear arguments as to why such work does not render your patent invalid and the patent examiner accepts those arguments, it is very difficult for your opponent to use that prior work against you later.

Granting of a patent

Filing for a patent is not the same as having a patent granted. The patent examiner assigned to your patent will attempt to find legal reasons to reject your patent. They are not being mean, it is their job. The address this problem on a claim by claim basis. For each claim they take it apart into the elements that make up the claim. What they will try to do is find a single piece of work that contains every element of a claim. For an independent claim those elements are in the claim itself. For a dependent claim the elements are all of those in the claim and all of those in the claim it is dependent upon. For example if claim 5 has elements U, V and W and is dependent upon claim 2, which has elements A, B and C then the elements of claim 5 are A, B, C, U, V and W.

If the patent examiner cannot find a single piece of work that has all the elements of the claim, then they will try to find multiple pieces of work that together have all of the elements. The examiner then must show that the combination of these is obvious. The examiner may also assert that a piece of work has element U or V simply because the same words are used. Patent examiners are not experts in your field. The patent examiner will issue an “office action” that usually rejects all of your claims and provides reasons. You and your patent attorney prepare a response that politely shows why the patent examiner was wrong. This process can iterate several times with you rewording claims, making arguments and generally trying to work things out with the examiner. Do not enter this process without an experienced attorney. They have been through this many times, frequently with this particular patent examiner. You need a lawyer’s help here, which will cost more money.

Finally you have overcome all of the objections of the patent examiner and your patent is granted. This is a good step, but not the final one. The examiner’s efforts to find ways to declare your patent invalid are limited. They look a lot at prior patents, but not so much at the published papers or books in your field. The real test comes when you make a claim that someone has infringed your patent.


You now have a patent and a filing date. You are watching for other people’s work that occurred after your filing data that matches every element of at least one of your claims. If that is true then they have infringed your patent and you have the right to sue for damages. You may not want to sue for damages (which can be expensive). Rather you want to enter negotiations that will provide you with an economic advantage.

see: Patent Strategy

In an infringement case you will try to prove that your opponent has practiced all of the elements of at least one of your claims. Your case is much stronger if there are multiples of your claims that have been infringed. Your opponent will try to bend the terms of your claims so that they do not match their work. If they argue successfully then there is no infringement. All they need to do is show that one of the elements of a claim is not practiced by their work. This would show that they do not infringe upon that claim.


Figure 2 – Invalidity

As shown in figure 2 your opponent will attempt to find other work that occurred before your filing date that practiced all of the elements of your claim. If they find such prior art, then your claim is invalid and your infringement case evaporates. This is why you need to pay attention to other people’s prior work when making an application. Sometimes they will not be able to find a single piece of work that covers all of the elements but will find several and claim that the combination is obvious. That is a weaker case to make but if argued well may persuade the court. Expensive expert witnesses will be hired on both sides the support or refute the obviousness argument.MultipleClaims

Figure 3 – Multiple claims

Figure 3 shows why you want multiple claims and dependent claims in your patent. In figure three you have one overarching independent claims. There are three claims dependent on the independent claim and then two of those have further dependent claims. Your opponent has found a piece of prior art that renders your independent claim and one of your dependent claims invalid (shown in yellow). You still have four claims (shown in blue) that are intact and your opponent is still infringing. The range of coverage of your patent is not as wide as you would have liked, but it is still intact and offering you economic advantage.

This discussion has focused on the patenting process. Also of interest is the way in which patents can be used strategically to secure your technical advantage.

see: Patent Strategy