Return to claim (idea)
From a [lawyer]'s perspective, the "claims" are the most important component of a [patent]. A [scientist] or [inventor] will be more interested in the [description] that follows the claims, since it actually shows what the invention is and how it works. The claims, which more closely resemble [gobbledygook] to the average person, are what define the scope of the patent—which devices its [monopoly] will cover, and which devices will be unprotected. [Infringement] cases always revolve around the claims, not the description, although the description can help to clarify the meaning of the claims.
Here are the first seven claims in U.S. Patent No. 6,972,748, awarded to [Microsoft] a couple of days ago.
The first claim is an "[independent claim]," so called because it doesn't refer to any other claims. The next six claims are all "[dependent claim]s." Claim 2 is dependent upon claim 1: if claim 1 is invalidated, claim 2 falls as well. Since 3 is dependent on 2, 3 would also be invalidated. And, by [domino effect], the whole patent would be lost.
Note that all of the claims above are for [method]s. Microsoft couldn't patent the actual device in claim 1: it's a [joystick], and they didn't invent the joystick. What they're patenting is a use for the joystick. A claim can also cover an actual device, like this claim from U.S. Patent No. 4,239,129 ():
1. A [toy] comprising an elongated [housing] having a [chamber] therein for a [liquid], a [pump] including a [piston] having an exposed [rod] end extending rearwardly of said toy facilitating [manual operation] for building up an appreciable amount of [pressure] in said chamber for ejecting a stream of liquid therefrom an appreciable distance substantially forwardly of said toy, and means for controlling the [ejection].
It's a [water pistol]!
The precise wording of the claim is very important. The holder of the water pistol patent, for instance, tried to sue [Larami], claiming that their [Super Soaker] line was infringing the patent. The [district court] dismissed the suit because the Super Soakers had chambers outside the housing, thus making them fall outside the scope of the claim. See Larami v. Amron, 27 U.S.P.Q.2d 1280 (E.D. Pa. 1993).
Many other claims follow a "[means plus function]" structure, where they vaguely decribe a "means" for achieving some "function." For examples, see the [means plus function] node.