EDTx Hands Down Indefiniteness Ruling in Semcon v. TCT Mobile

The Eastern District of Texas recently issued a claim construction ruling with a couple interesting rulings on indefiniteness in the case of Semcon IP v. Louis Vuitton and TCT Mobile (April 29, 2020).

TCT Mobile is a mobile communication company whose brands include Alcatel, Blackberry, and TCL Communications. Semcon IP is a patent assertion entity whose patents cover “fundamental technology for adjusting the processor clock and voltage to save power based on the operating characteristics of the processor.” The patents include Nos. 7,100,061; 7,596,708; 8,566,627; and 8,806,247, all part of the same family. Semcon sued TCT Mobile, along with fashion brand Louis Vuitton, for infringement as part of an assertion campaign against multiple companies in the Eastern District of Texas.

While the court construed twelve terms in its 64-page ruling, the most interesting rulings were on indefiniteness of two terms appearing in dependent claims of the asserted patents. The court found “sleep state” definite but “said change in operating conditions” indefinite.

The basis for questioning the term “sleep state” is that the term only appears unqualified in the claims, not the description. Instead, the description only discusses a “deep sleep state.” Semcon contended that the deep sleep state discussed in the description is one example of a sleep state, and that the term “sleep state” is well understood, as evidenced by other examples of sleep states from technical data sheets for processors. TCT provided expert testimony and pointed to the court’s earlier claim construction ruling in Semcon’s case against Huawei, in which the court stated that “sleep state” and “deep sleep state” are not synonymous. The court found the expert testimony conclusory and unhelpful, and agreed with Semcon. Understanding a deep sleep state as an example of a sleep state does not require that they be synonymous.

Semcon did not fare as well with the term “said change in operating conditions,” which the court found indefinite. The disagreement here was over antecedent basis. The chain of dependency for the claim including the term does not recite the words “a change in operating conditions” but does recite “a change in frequency of said first clock signal,” “adjust said first clock signal by a first value,” “adjust said clock signal by a second value,” and “change said first value to a third value and to change said second value to a fourth value.” Semcon pointed to these terms as providing an antecedent basis. The court disagreed. “It is not clear whether the change in operating conditions refers to the generic change in frequency of the first clock signal in the PLL circuitry, the first-value adjustment to the first clock signal, the second-value adjustment to the second clock signal, the change in frequency to provide the processor frequency (due to the first-value adjustment), or the change in frequency to provide the component frequency (due to the second-value adjustment). Perhaps the change in operating conditions refers to all of these or some subset of these?” Thus, the term was indefinite.

Lessons for Practice

These two rulings show the importance of supporting the exact words used in the claims. If a term requires antecedent basis—i.e., begins with “said” or “the”—then the words should track the words of that antecedent basis to best avoid controversy. (You should use “the,” not “said,” to make the patent at least a little closer to how a normal human being talks.) Beyond that, every term in the claims should be supported verbatim in the description. While Semcon won that fight, the fight could have been avoided altogether if Semcon had used “sleep state” in the description. This advice suggests not just double-checking that the claims are supported in the description, but also writing the description such that it could support additional claims. This case featured four patents, three of which were continuations, meaning that their claims were not drafted until well after the description was written.