Single Embodiment Of Claim Element Fails To Describe Element Generically

Patentlyo007LizardTech v. Earth Resource Mapping (Fed. Cir. 2005).

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.


  • I see this as a quite odd decision.  First, although claim 21 arguably covers either “seamless DWT” or  “non-seamless DWT,” such a result is explicitly claimed.  The CAFC did not point to any element of claim 21 that was not sufficiently described.  Rather, the court found the claim invalid because an an embodiment arguably covered by the claim (seamless DWT) was not sufficiently described. 
  • A fellow patent attorney and Patently-O reader e-mailed this morning with a different take:

Section 112 requires that the patentee have both possession of the invention and an enabling disclosure. In this case, the Court found that because the patentee had only described (and apart from claim 21) claimed the one embodiment that required “maintaining updating sums of DWT coefficients” this shows that the method including this element was really the scope of what the patentee considered their invention. That is, the patentee didn’t think they had invented a more generic way of creating a seamless DWT that did not include that element.

The Court went on to say that any such generic method is also not enabled — first because it is not described in the specification and second because it is not within the ability of one of ordinary skill to practice without undue experimentation. As the Court noted, both these requirements usually rise or fall together. The last paragraph of the opinion makes clear, however, that even assuming that patentee had possession of this invention (by virtue of claim 21 being part of the original application) the claim is still not enabled. That is, even if one of ordinary skill in the art read claim 21 and recognized that it covered a generic method of creating a seamless DWT, that person still would not have been able to come up with the generic method (i.e., one not using the updating sums element) without undue experimentation. Therefore, the claim doesn’t satisfy the requirements of 112.

Thus, after this case (and as was the case, no pun intended, before LizardTech) one is free to describe one or more embodiments in the application and draft claims that cover other broader embodiments that are not described in the application. Those broader claims will be valid provided that the patentee had possession of those broader embodiments and the broader embodiments are enabled. Presumably they would be enabled because, even though not described in the application, they would still be within the ability of one of ordinary skill in the art to practice without undue experimentation.

  • The lesson for prosecutors is that broad claims will generally require multiple embodiments of each element. Specifically, if you claim A+B+C+D, do not expect that you can claim A+B+C without adequately disclosing that D is not necessary or that D can take alternative forms.
  • Philip Mann of IP Litigation Law Blog was counsel for LizardTech.


2 thoughts on “Single Embodiment Of Claim Element Fails To Describe Element Generically

  1. 2

    District Court Deemed LizardTech’s DWT Patent Invalid

    Patently-O: In an interesting case, LizardTechs patent on Discreet Cosine Transform has been deemed invalid. Reason: Single Embodiment Of Claim Element Fails To Describe Element Generically

  2. 1

    Patently-O: Patent Law Blog: Single Embodiment Of Claim Element Fails To Describe Element Generically

    Link: Patently-O: Patent Law Blog: Single Embodiment Of Claim Element Fails To Describe Element Generically. Excellent material.

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