A strong patent is more than just a strong invention.  Improperly prepared and prosecuted, a wonderful invention could result in a week or even useless patent.  As a patent is a “deal” bargained for between the patent owner and the government, a strong patent is a superb bargain for the patent owner, while a weak patent is a lousy bargain for the patent owner.

A strong patent makes it hard for the competitor to get over or design around the invented technology without licensing the patent, while a weak patent leaves doors open for others to copy the technology without infringing.  In a worst case, a weak patent may essentially do nothing but teaching others how to copy the technology without infringing.

It must be made clear that a premise for a strong patent is firstly a strong invention.  This article therefore describes the quality of a patent in a relative sense only.  No one can craft a strong patent out of a weak invention.  It is rightly so, for otherwise the patent law may be unjust to the public.  As a Chinese saying goes, a skilled wife can’t make a bread without flour.  In our “land and fence” analogy, one may build a quality fence for anything but the the resultant protection can be of no meaning without a good piece of land to be protected in the first place.

A good piece of land is characterized not only by the size of the land but also the location of the land.  By the same token, a strong invention is characterized by both the scope of the invention and the strategic position of the invention on the technical map of making a product.

But a strong invention does not necessarily result in a strong patent.  In the land-and-fence analogy, a good piece of land may end up with little protection if the fence does not measure up to it.

Sometimes a patent owner might follow a rationale like this to justify using patent services of lesser quality and lower costs: Sure it would be nice to be able to protect everything, but it may be a good cheap option to get just a part of the “land” protected; it’s not everything, but at least it’s a good piece of that.  This is a false rationale.  This is where our “land and fence” analogy lacks and needs to be modified.  In all practical sense, the patent “fence” is really not to protect the land itself but to protect a “treasure” hidden either in the land or in a land on another side of the territory.  This is because, as far as a patent right is concerned, it is really not a right for the patent owner to enjoy the land itself, but instead a right to exclude others from passing through the land.

Speaking in commercial terms, the “treasure” is an inventive product.  For this reason, a partial fence or broken fence is often no fence at all because although it may protect part of the land, it leaves open a certain route for an intruder (that is, a competitor) to access the “treasure,” which is the only thing that really matters in the end.  For the intruder, it matters relatively little what particular route is available as long as it provides him an access to the treasure.  For the landowner, once the treasure becomes accessible to others, the protection loses its meaning even though he still possesses a part of the land.

The difference between a strong patent and a weak patent is therefore far more critical than a proportional and quantitative difference.  When a patent becomes the subject of an infringement lawsuit, the difference between a good patent and a not-so-good patent is whether the patent owner takes all or loses all.  It is a peculiar nature of patent lawsuits that the outcome of the entire case, no matter how much money is at stake, is typically determined on certain nuances in the patent description and the claim language.  The alleged infringer either infringes or not, and accordingly the patent owner is either awarded all the damages or nothing.  The jury or judge is not going to award 90% of the damages to the patent owner on a basis that the patent claim is 90% infringed by the alleged infringer’s product, and so on.