Interpreting and Defining the Words in a Patent. Episode 83

The Importance of Claims in a Patent

I’ve talked before about claims in a patent. The claims define what your invention is. For example, you might claim a machine having parts A, B, and C, and then go on to define what A, B, and C are.

For an avocado 3-in-1 splitter, pitter, and slicer, those parts could be:

• The splitting blade that cuts the avocado into two halves.

• The pitter that removes the pit.

• The multi-blade loop for slicing.

For someone to infringe, their product must have all three of these elements. I’m simplifying this invention, but my point is to remind you why claims are important. In this episode, I’ll talk about how words in a patent are defined and interpreted, and why this matters.

The Power of Word Definitions in Patents

Let’s say your claim states that part A has a blade. Now, someone designs a similar avocado 3-in-1 device, but instead of using what we traditionally consider a blade, they use a dull, thick, flat-edge piece.

It might not work as well as a sharp blade, but they did this to avoid infringing your patent. If you sue them for infringement, they might argue:

“Your patent requires a blade. What we have is not a sharp edge; it’s a long piece of plastic with a dull, thick edge. Therefore, we are not infringing your patent.”

So how do we determine whether they are infringing? It all depends on how a judge defines the word blade.

Different Approaches to Defining Patent Terms

There are several approaches a court might take to define a term like blade:

1. Dictionary Definition: The judge could look up the word blade in a dictionary and compare that definition to the accused product.

2. Patent-Specific Definition: The judge could examine how blade is defined in your patent. Does your patent state that a blade must have a sharp edge? Or does it define a blade as any long member capable of piercing and splitting an avocado?

3. Industry Experts: The court could bring in experts from the blade industry to testify on what a blade means in their field.

   
   

These approaches might lead to conflicting interpretations. So, which one is correct?

The Phillips v. AWH Case and Patent Term Interpretation

The Phillips v. AWH case (2005) clarified how courts should determine the meaning of words in a patent. The case involved the term steel baffles and whether baffles could be angled or had to be positioned at 90 degrees. The details of that case aren’t important here, but the decision established a hierarchy of sources for defining patent terms.

Hierarchy of Sources for Defining Patent Terms

The first sources to examine are intrinsic sources, which include:

1. The Patent Document Itself: The ordinary meaning of the word in the context of the patent document is the first place to look.

   • If the inventor explicitly defines the term in the patent, that definition controls.

   • Example: If the patent states, “A blade is defined as a long member with an extremely sharp edge,” then that’s how it must be interpreted.

   • Conversely, if it states, “A blade is defined as a long member that may have either a sharp edge or a dull, flat edge suitable for splitting an avocado,” then that broader definition applies.

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2. Patent Prosecution History: This includes any discussions or arguments made during the patent examination process. If, during prosecution, you told the examiner, “Our blade must have a sharp edge,” then that definition applies, even if your claims don’t explicitly state it. However, prosecution history is considered less authoritative than the patent document itself.

Only if the meaning of a term is still unclear after examining intrinsic sources can extrinsic sources be used. These include:

• Scholarly journals

• Expert testimony

• Dictionaries

  
  

However, courts should only rely on extrinsic sources if intrinsic sources fail to provide clarity.

Markman Hearings: Determining Definitions in Court

If you sue someone for patent infringement and there is a dispute over the meaning of a word in your claims, there is a preliminary step before the actual trial begins. This step is called a Markman hearing.

A Markman hearing is where the judge determines the meanings of disputed words before the trial proceeds. Once these definitions are set, the trial moves forward with those interpretations in place.

Strategies for Drafting Patent Applications

To avoid disputes over word meanings, it’s best to be clear in your application:

• Define key terms in your patent document.

• If necessary, expand definitions to cover multiple interpretations.

• Avoid overly broad or ambiguous language that could weaken enforcement.

  
  

That said, some ambiguity can be strategic. A broader definition may allow you to cover more potential infringers. However, it can also lead to legal disputes. Defining terms carefully is an important strategy when drafting a patent application.

Conclusion

That’s the basics of how words are interpreted and defined in a patent. Courts follow a hierarchy of sources, starting with the patent document itself before looking at prosecution history or outside evidence.

I’m Adam Diament, and until next time, keep on inventing!