The Data Compression News Blog

Patently-O: On summary judgment, the district court deemed LizardTech’s patent invalid for failing to meet the written description requirement of 35 USC 112 para 1. The asserted patents were related to the use of discrete wavelet transform (DWT) to compress digital images.

The specification provides an example method for creating a seamless DWT including the step of “maintain[ing] updated sums” — that procedure is the focus of claim 1. Claim 21, however, is a broader claim that lacks the “maintains updated sums” limitation. The specification did not explicitly describe a method that did not include that limitation. (Although claim 21 was included in the original disclosure)

On appeal, the CAFC paid lip service to the rule that a claim will not be invalidated under Section 112 for only disclosing a single embodiment. However, the court went on to determine that claim 21 was directed at “all seamless DWT’s” — a coverage not adequately supported by the single embodiment.

After reading the patent, a person of skill in the art would not understand how to make a seamless DWT generically and would not understand LizardTech to have invented a method for making a seamless DWT, except by “maintaining updating sums of DWT coefficients.”

[A] patentee cannot always satisfy the requirements of section 112, in supporting expansive claim language, merely by clearly describing one embodiment of the thing claimed.

As noted by David Long, this case is a “must read for those addressing written description (or enablement) issues.

There is alot more information available at original source including links to complete patent, complete case history and some very interesting comments.