Patent claim charts

Patent claim chart, with one row not matching
Patent claim chart, with one row not matching

Think that someone is infringing on your patent?  Worried you are infringing, or want to show a patent reads on prior art?  Analyze with patent claim charts.

The basic idea behind a patent claim chart is to first break a given patent claim down into a series of smaller sections, and then to determine if each smaller section matches a corresponding aspect of a target of interest. This target may be a potentially infringing product or service, another patent, or even a public domain product or service (to try to show that a patent may be invalid).

Patent claim charts usually follow a row and column table format.  One column contains various sections from a claim of interest, spread out over a number of rows.  Another column contains various aspects of a target of interest, also spread out over a number of rows.  Rows containing sections from the claim column are compared with rows containing aspects from the target column.

If it can be shown that every row from the claim column exactly matches up to one or more rows from the target column, then this suggests that claim does describe the target. Note, however, that although every claim row must match with a target row, there is usually no reverse requirement that every target row match-up with a claim row.

It sounds simple, but the devil is in the details.  Since patent claim charts are often part of an adversarial process (e.g. litigation), each side may feel under pressure to “slant” their claim charts in a way that favors their particular position.

Claim charts can be slanted in many ways.  One of the most common ways is to write the chart in a way that skips over important details, often by not breaking the claim down into small enough sections.

Some of the comparisons may not be accurate.  Also, remember that individual claim terms can sometimes be misleading because they may have been defined in the text of the patent application (or during prosecution), in a somewhat unexpected way.

So read and write claim charts with caution and skepticism.  Don’t use sloppy claim charts to initiate any legal action.  Of course, don’t blindly accept claim charts from others without doing your own independent analysis.

Medical device patents

Medical device patents
Medical device patents

Why are medical device patents important? New medical devices are both expensive and risky to produce. Without patent protection, few new medical devices would ever reach the market.

The number of filed and granted medical device patents has substantially increased over the last few years, with certain US states (California, Minnesota, and Massachusetts) leading the way.  Certain countries, in particular, Japan and Germany, are also heavily active in this area.

Write carefully: In contrast to some high tech areas, such as computers and software, which often rely on a larger number of lower impact patents, the medical device industry tends to rely on a smaller number of higher impact patents.  What this means is that any given medical device patent is more likely than average to be subjected to a high level of competitor scrutiny.  Remember also that in the medical device field, both the patent office and the courts may view the “person having ordinary skill in the art” (PHOSITA) as being highly skilled, such as a PhD or MD. Thus care should be given to write accordingly. It is helpful to include a lot of detail and discuss alternative approaches. Research and disclose prior art, and of course try to write claims in a manner that distinguishes over prior art.

Remember Europe: Medical devices are an international market, and often due to slower FDA review times, US firms first introduce new products in Europe.  Many US medical device patent applications end up being filed as international patent applications in Europe.  Thus European patent rules are often important.

Although there are a few glaring exceptions, US medical device patent eligibility rules generally tend to be expansive. The USPTO typically reviews these patents in its 3700’s art unit.  In recent years, this art unit has continued to grant medical device patents according to its historical percentages.

European patent eligibility rules are also generally quite permissive with regard to “gadgets” and in-vitro devices, as well as technical aspects of in-vivo devices.  However, Europe (See G-II 4.2.1) doesn’t allow “methods of treatment of the [living] human or animal body by surgery or therapy and diagnostic methods practiced on [usually interpreted as “in”] the human or animal body “ (the US has a similar carve-out for medical procedures). Fortunately, the Europeans tend to read this exclusion narrowly, so this isn’t actually quite as restrictive as it sounds.

However, from a claim writing perspective, be careful of method claims with limitations that read on the patient’s body.  Try to focus more on the details of how the gadget (device) itself works.  Watch out for methods that remove a tissue, treat it, and then return it to the body, as these could run into trouble.