A patent is a government grant that gives an inventor a monopoly on the patented technology. For 20 years after the inventor applies for a patent, no one else can make, use, sell, offer for sale or import a product that uses the invention protected by the patent's claims. The inventor can sue for patent infringement if she finds someone using her patented technology. In a patent infringement lawsuit, the inventor must prepare a patent claim chart that describes how the accused product infringes the patent.
Locate the claims in the patent at issue. The claims establish precisely what the patent protects. Claims are easy to find in a patent. Look for the language that says "what is claimed is ..." The claims are located in the numbered paragraphs immediately following that phrase.
Create a table two columns wide and several rows deep. Break the claim language from the patent into phrases, and type one phrase in each cell going down the first column. As an example, for US Patent no. 6,263,732, a patent for a special kind of measuring cup, the patent claims: "A measuring device, comprising: a bottom wall and a generally vertical and encircling side wall having a lower edge and an upper edge." In a claim chart for this patent, you would write in column 1, row 1 the phrase "a measuring device, comprising." In row 2, write the phrase "a bottom wall." In row 3, write "and a generally vertical and encircling side wall." In row 4, write "having a lower edge." In row 5, write "and an upper edge."
Examine the product that is accused of patent infringement. In this example, the accused product would be a measuring cup that contains the technology claimed in the patent.
Write a description in column 2 that summarizes how the accused product copies the claim in the cell on the left. Returning to the example, where the claim language is "a measuring device," the claim chart in column 2, row 1 would describe how the accused device contains markings used for the purpose of measuring the volume of the contents of the device. Column 2, row 2, would describe how the accused device has a bottom wall, like the bottom wall claimed in the patent.
Compare every element of every claim to the accused product and describe how the product infringes every element until you have covered all of the claims in the patent.