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Preserving Your Patent Rights

Below are several articles to familiarize MIT inventors with and answer the most common questions about the patent process.

Protecting Your Ability to Get a Patent: What Counts as a Bar to Patenting

The Patent Process: Claiming your invention

Controlling Patent Costs

Patent Application Checklist

Protecting Your Ability to Get a Patent: What Counts as a Bar to Patenting

1. What are the rules if I want only a U.S. patent?

The U.S. patent law system is among the most lenient in the world with regards to prior disclosure of your invention. It allows you to publish your invention or offer it for sale prior to filing a patent application, provided that you file your patent application within one year of the publication or offer for sale. If you wait longer than one year, your patent rights are forfeited. The one-year period is a "grace period."

2. What if I also want patent coverage in Europe and other countries?

Most countries are stricter than the U.S. They require that a "priority patent application" be filed before the first public written or oral disclosure.

3. Do I have to file in all the countries before I disclose the invention publicly?

No. You only have to file a patent application in one country before you make the public disclosure. You then have another 12 months after that "priority filing" to file in all the other countries (or regional territories) in which you want patent protection. (Usually, the first filing for Americans is in the U.S., but any of about 130 other countries could do.)

4. What type of medium counts as a public disclosure that bars a patent?

"Public disclosure" is not confined to publications in books and technical journals. Poster sessions, slides, lectures, seminars which are open to the public, letters, even conversations can count as a bar to patentability--depending on the country.

In particular:

  1. Any written or oral disclosure, even to a single person, counts as a "public disclosure" in most countries--unless the recipient agrees that the information was conveyed in confidence. Disclosures to employees are not considered to be "public disclosures."
  2. In the U.S., the "public disclosure" must be a "publication"--that is, in writing. However, do note that slides at meetings and poster sessions are "publications"--as is private correspondence, advertisements, etc.
  3. An "offer for sale" counts as a bar to patenting (after the one year "grace period") in the U.S. Showing your product at a trade show may very well count as such.

5. What content counts as public disclosure?

Simply announcing that you have made an invention is not a "public disclosure" of the invention. In order to act as a patent bar, the disclosure must be "enabling"--that is, it must teach someone "of ordinary skill in the art" how to actually duplicate the invention.

An offer for sale, even if it does not teach someone how to make the invention, is a bar to patentability (after the grace period) in the U.S., but is not a bar in Europe if it does not "enable".

6. What if I want to discuss my invention with others, outside my institution, before I have filed a patent application?

You should have the person (or company) sign a confidentiality agreement, agreeing to keep your invention in confidence, before you have the discussion.

7. Is there any forgiveness if I accidentally make a public disclosure?

In the U.S., as stated above, you have a one year grace period after the publication in which to file the patent.

In Europe, a public disclosure is an absolute bar to patentability.

Japan gives a six month grace period for filing a patent if the public disclosure was a presentation at a scientific meeting.

Check with a patent attorney before despairing or deciding not to try for a patent. Your "public disclosure" may not have been enabling, or there may be some residual valuable, patentable information that you did not disclose.

The Patent Process: Claiming your invention


A patent application cannot, and should not, be written without your contribution as the inventor. The patent attorney needs your assistance in understanding the essence of your invention and in finding the words to describe it. The perfect patent claims the essence of your invention, no more, and no less.

The purpose of this memo is to suggest ways in which you, the inventor, can help the patent attorney find the words to describe this essential idea. Following are a number of examples, some purely imaginary and others that have arisen over the years at MIT, that illustrate various patenting situations.

What are claims?

Claims in a patent can be understood as a written boundary describing exactly what part of the practical arts the holder of the patent has the right to forbid others from practicing (see previous memo on the definition of a patent). A helpful analogy might be to imagine the claims as a real estate map, delineating proprietary rights; or as verbal Venn Diagrams.

After completing your literature search, you should have a good idea of what you can't claim, because it has already been published by others. How do you figure out what you can claim?

Example A
If you have a patent on a three legged chair, you have the right to forbid others from making, using or selling all such chairs, whether they have improvements, such as backrests or coats of paint, or not.

Example B
If you have a patent on all anti-fuse structures which consist of a sandwich of layers of metal, insulator, and metal, such that a voltage through the two metal layers will break down the insulator and create a permanent current path, then you have the right to forbid others from making any such device, regardless of the specific types of metal, or insulator, of the specific thicknesses of layers called out in subsequent improvement patents.

These subsequent patents may have extremely important practical innovations in them, and it might be necessary to practice the particular "recipe" they describe in order to mass produce practical and robust anti-fuses, but the first case would dominate, and a person would require a license from the "broad," or, in legal terms, "dominant," patent holder in order to practice the practical improvements. Happily, though, it works both ways, and the holder of the dominant patent also needs a license from the holder of the "improvement" patents in order to practice those improvements.

What can't be claimed?

You can't claim what others have already published, either in patent or scientific article form, or a design for an object which has been available for sale (hence the importance of a literature search). You also can't claim what you have absolutely no idea how to make. You can't claim anti-gravity paint, or perpetual motion machines for example.

Can I only patent something that I have actually built?

No, you don't have to have built it. The patent office says that you have to do at least a "constructive reduction to practice". A patent application constitutes a "constructive reduction to practice" provided that, in the application, you show that by the generally accepted laws of nature, your invention should work in theory, even if you have not yet built it. Incidentally, idea patents alone (no experimental reduction to practice) tend not to be very commercially valuable, and in general, our office discourages them. Preferably, you, the inventor, have done an experiment to demonstrate feasibility.

Commercial Uses of Patents

First, recall that the right to forbid others from practicing something can attract investment to forward-looking commercial ideas (such as superconducting wire), which might not otherwise have been attracted. This is so because investors are more willing to put large sums of money into uncertain ventures if they know that, should they in fact succeed in working out all the technical bugs, they will have some period of time during which they will have a monopoly, and can keep their competitors from copying their design.

Therefore, sophisticated investors and potential licensees will calibrate as accurately as they can the position of your invention relative to the prior art. Does it dominate most of the inventions in the field, or are there some basic patents which dominate your invention?

Investors and licensees, like good engineers, also search for alternate ways to accomplish what your invention accomplishes. How is your invention better, not just different from the prior art? Please contrast and compare your invention with the prior art for your attorney, who will use this material for the section of the patent entitled "background of the invention".

Finally, investors and potential licensees may try to imagine methods for "engineering" around your invention. Can they practice your invention without, technically, infringing the claims of the patent?

Therefore, in order to increase the commercial value of their patents, MIT inventors need to help us identify the prior art, explain the relevance of this art to their patent attorneys, and explain the essence of their invention to the attorneys so that it is virtually impossible to engineer around their invention without infringing the claims.

Specific Hints for Inventors on How to Broaden Claims

  1. Is anything in the patent unnecessarily specific?

    Example A
    A particular material (like GaAs) is called out, where such a material is unnecessary. Could the invention be practiced just as well with any III-V material, with any direct bandgap semiconductor? Is it an electronic invention, where the optoelectronic properties are irrelevant? Alternately, if it is an invention that specifically requires the presence of arsenic, then maybe it has to be written to any III-V compound containing arsenic.

    Example B
    A particular dimension is called out. Does the layer really have to be 100nm thick? Is that an essential feature of the invention? Could it be between a range of values, say 75nm-150nm? Does it have to be an integral multiple of 100nm? Does it have to be an integral multiple of a wavelength of light times the refractive index of the layer in question? Is the actual dimension actually irrelevant?

    Example C
    A particular means is given for creating something, but the means that is used is irrelevant.

    • Do you specifically need an MBE machine to make the multi-quantum well laser that is at the heart of the invention? Could it be done with MOCVD, by LPE? If it really doesn't matter, don't specify the means at all, at least not in the broadest claims.
    • Do you specifically need to make a certain structure by etching (subtractive means), or could it just as well have been built up by deposition (additive means)? If it doesn't matter, don't specify.

    Example D
    A particular property is specified, but it is unnecessarily, or incorrectly specific.

    • "Hydroscopic" replaced by the broader "electrostatically repulsive".
    • "Transparent", replaced by the more correct and also flexible "Transparent to the lasing wavelength".

  2. By focusing on specific examples, have you neglected to express the true essential idea? By going through the check-list of the previous examples, you hope to have arrived at the most abstract, algorithmic, yet still correct formulation of your invention.

    Example A
    The essence of the invention was an electronic energy level filter for selecting beams of electrons within a narrow energy bandwidth. It was important to specify the energy structure of the materials used to make the filter, and the algorithm used to specify how many layers of what types of material were needed to produce the desired filtering effect. Calling out specific materials and specific layer thicknesses would have been unnecessarily limiting.

    Example B
    The essence of the invention is a means for independently engineering both the gain profile and the numerical aperture of a lasing medium by distributing a gain medium in a (non-lasing, and transparent to the lasing wavelength) medium of preselected refractive index. Calling our particular wavelengths and particular numerical apertures would have been unnecessarily limiting.

Help the Attorneys Write Good Dependent Claims Too

In the dependent claims, it is completely appropriate to call out the specific material, dimensions, designs, and tools you used to reduce your invention to practice. Good dependent claims make the patent easier to understand, easier to enforce, and easier to license.


  • Limit the scope of your patent by thorough and determined literature searches. Anticipate the references that savvy investors and potential licensees will probably find, thus saving time and money.
  • Broaden the scope of your patent by testing your ability to formulate the most general, yet still correct algorithm which explains the essence of your idea.
  • Clarify your patent by giving specific examples to the attorney for the dependent claims.
  • Do all this, and you will have the clearest, most commercial valuable patents possible.


Controlling Patent Costs by Kirk Teska


The following article on "Controlling Patent Costs" was written by Kirk Teska. Kirk is adjunct law professor at Suffolk University Law School, and is the managing partner of Iandiorio Teska & Coleman, an intellectual property law firm in Waltham, Massachusetts.

Reining in Patent Costs: Communicating with Your Patent Attorney


Be clear and complete. The less legwork you leave for your attorney, the lower the fee to your company.

If you hold a patent for something that everybody wants, you can make a fortune. And when you’re rich and your patent expires, society in general can benefit from what you invented.

Of course, life doesn’t often work like that. The inventions covered by some patents have no takers. They can be overshadowed by something that is perceived to be better or is more widely advertised. So there’s a risk involved in applying for a patent, because, as savvy readers know, patents are expensive.

According a 2007 survey, the average cost for a utility patent application in the United States is around $12,000. By the time the patent is granted, the total cost could easily exceed $20,000.

There is really no such thing as a poor man’s patent. In the United States, there is a provisional patent application, which may cost a fraction of a regular utility patent application, but that’s a false economy.

Indeed, it’s an extra expense: whatever the provisional application costs, it’s an added cost, since a provisional does no good unless a utility patent application is prepared and filed within a year of the provisional.

But there are ways to lower the cost a patent attorney charges for drafting an application by reducing billable hours. In my experience, the more information that I do not have to chase down and the more concretely the invention is described, the less time that I will need to draft a given patent application.

As for basic patent application drafting information, provide any information that the attorney will need in order to set the deadline for filing the application. Has the invention been described in a published paper or embodied in a product sold or offered for sale? Are any of these events planned in the near future? If so, tell the attorney.

List the names, residential addresses, and citizenship of all the likely inventors. List and provide a copy of all relevant prior papers and patents you know about that are related to the invention. Many companies use “invention disclosure” forms for these purposes.

Also, manage your patent program. You can bet a patent attorney will charge a lot more for a patent application that must be filed in one week versus a patent application that does not have to be filed until next month.

How about if the inventors write a rough draft patent application to be later polished by the patent attorney? It rarely helps me to start with such a rough draft of a patent application written by an engineer.

Patent attorneys think in terms of problem/solution statements. If you invented the basic paper clip, I might describe its advantages like this: the problem with staples, which punch holes in the attached pages and which are difficult to quickly remove, is solved by a bent wire which keeps the pages together via a spring force action. Engineers, in contrast, typically begin by describing dimensions, tensile strengths, materials, and the like.

The more concretely the true invention is described, the better, since inventions rarely have anything to do with dimensions, tensile strength, materials, resistance and capacitance values, or other details.

Do include with the invention disclosure form drawings of the invention from a highly conceptual level (in a product or system, where does the invention lie?) and then down to the nitty gritty details. Study the patents of others to learn what goes into them and how they are formatted.

Armed with the basic information and a concrete description of the invention, the patent attorney is ready to meet with one or more of the actual inventors. To ensure that you receive a quality first draft of the patent application, make sure that the patent attorney completely understands the true invention and its value proposition, that you understand what the patent application will cover, and that your understandings are the same as the patent attorney’s.

Any disconnect between you and the patent attorney will only lead to rewrites which increase the cost. One worst case scenario is when you think the invention is X and the patent attorney procures you a patent covering invention Y. The probability of a disconnect is increased when the face to face meeting is forgone.

After the first draft of the application is received, have everyone review one copy. If the attorney has to incorporate changes from three different inventors and one project manager via four separate versions of the application lying on her desk, that will take extra time and result in a higher cost. The goal is to edit a first draft, incorporate the inventor’s comments, and file the edited application with the Patent Office. As you become more and more patent savvy, you will enable the patent attorney to work faster and eliminate multiple drafts of an application.

So, why not just do most of the work for the attorney and write a rough draft of the application yourself? Because patent attorneys write patent claims first. The rest of the patent application is based on the claims for a variety of legal reasons. So, drafting a patent application without writing the claims first just doesn’t make sense and results in the attorney having to rewrite your initial write-up anyway.

That being said, you can draft short descriptions of why the invention is advantageous and what you know about prior versions of the same thing as well as the problems associated with them. If the patent attorney then asks you to describe in writing a specific alloy, drive train, circuit, or the characteristics of a device, do comply so that the attorney can cut and paste your write-up into his.

Finally, if the patent attorney is willing, ask for a discount for multiple applications and/or fixed cost applications. The overall cost may not be that much lower, but at least you will know the cost ahead of time and can budget your patenting efforts accordingly.

Patent Application Checklist

• List all known “prior art” (anything that predates the    invention).

• Discuss the shortcomings associated with the prior art.

• Discuss how the invention is different from the prior art.

• Tell exactly what it is that makes the invention different.

• List the advantages of the invention. Think about how the    marketing department will tout a product including the    invention.

• Take the time to write a short value proposition. Sleep on it    and edit it. Have all the inventors agree on the wording.

• Describe any sales or prior uses of the invention and any    papers or other publications describing the invention.

• List all the likely inventors. Include their names, residential    addresses, and citizenship.

• CAD or detailed engineering drawings are not required.    Sketches are usually OK.

• Are there any pending patent applications or issued patents    related to the invention? If so, list them.