Patent claims - when less is definitely more.

Claims are the most important part of a patent. Normally, most of a patent will be taken up with describing what the invention does and how it works. The claims on the other hand set out the legal boundaries on that invention and define what the owner of the patent can or cannot prevent a competitor from copying or otherwise using.

There is an inherent contradiction in any patent claim. On the one hand, they do need to clearly define the invention so that anyone reading the patent can understand what it is that the patent owner is trying to prevent them from doing. On the other hand, they are normally as general and all encompassing as possible. I think Vroomfondel the philosopher (with apologies to Douglas Adams) summed it up best when he demanded "rigidly defined areas of doubt and uncertainty."

With that in mind, it isn't really surprising that the language used to write patent claims can get a bit contrived. To use a slightly facetious example, imagine two claims for a chair. (If you're a patent attorney, please also gloss over the less than rigorous drafting. Thanks.)

a)   A wooden chair consisting of an upholstered seat, four supporting legs fixed to the underside of the seat and a back support extending generally upwardly from the seat.

or

b)  An article of furniture comprising a seat and at least one supporting leg attached thereto.

Claim a) is pretty restrictive or narrow. With a bit of imagination, it is describing a fairly conventional style of chair. The image that comes to my mind is a kitchen or dining room chair but with a bit of effort (and a generous definition of 'supporting leg'), I can just about stretch that image to include an armchair. However, claim a) will only prevent rival chair makers from making or selling a limited range of chairs. Any competitor that sells a four legged stool (no back support) won't be particularly concerned by this patent . Similarly, competitors selling plastic or metal chairs (not made of wood) have nothing to fear.

Claim b) on the other hand is very general or broad claim. Almost any chair, and many other bits of furniture, will include a seat and one (probably more) legs . Metal, wood, plastic, cardboard - it doesn't matter. The claim doesn't specify a particular material so all materials are covered by the claim. Similarly the claim doesn't specify an exact number of legs. Competitors making three legged milking stools, one legged shooting sticks, or 22-legged designer chairs will all be blocked by the patent.

 Less is more.

- Richard.