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How to (Not) Prove Infringement of a Means-Plus-Function Patent Claim: SPEX Technologies, Inc. v. Apricorn

A patent plaintiff saw its jury trial victory vacated when the court granted a defense motion for judgment as a matter of law under FRCP 50(b), finding that the plaintiff had not proved that the accused products had structure corresponding to claimed means.  SPEX Technologies, Inc. v. Apricorn, No. CV 16-07349 JVS (AGRx) (C.D. Cal. Aug. 10, 2020).

The jury found infringement of claims 11 and 12 of U.S. Patent No. 6,088,802. Those claims recite:

11. A peripheral device, comprising:

security means for enabling one or more security operations to be performed on data;

target means for enabling a defined interaction with a host computing device;

means for enabling communication between the security means and the target means;

means for enabling communication with a host computing device; and

means for mediating communication of data between the host computing device and the target means so that the communicated data must first pass through the security means.

12. A peripheral device as in claim 11, wherein the target means comprises means for non-volatilely storing data.

During claim construction, the court had found that an “interface control device 910” disclosed in the ’802 patent specification was the structure corresponding to the recited “means for mediating communication.” The defendant had argued that this claim term was indefinite.

The patent specification included the following:

The interface control device 910 includes sets of configuration registers 911. The data stored in the configuration registers 911 establish operating characteristics of the interface control device: in particular, the content of the configuration registers enables the interface control device to present to the host computing device a desired identification of the peripheral device, and determines whether data passing through the peripheral device must be subjected to security operations.

Based on the emphasized language, the claim construction order found that “significant additional details” about how the interface control device 910 interacted with other structures were provided to a person skilled in the art. Accordingly, the claim construction order stated that the defendant had failed to prove” by clear and convincing evidence that the structure of the interface control device [910] is inadequately disclosed by the patent specification.”

Following trial, however, the court agreed with the defendant’s argument that the plaintiff had not proven “that the ‘means for mediating’ limitation is met by the accused products” because the defendant’s products do not use the described configuration registers. The plaintiff’s technical expert made one short statement on direct examination at trial that the accused products “need to be configured, so there’s always configuration information that they can be programmed with.” The court explained that:

testifying that the accused devices perform the function of “be[ing] configured” is not the same as saying the accused devices have an equivalent structure to the configuration registers disclosed in Interface Control Device 910.

The court further agreed that “the record does not support a new trial.” The plaintiff had argued that it had provided further evidence relating to configuration registers. But this evidence was presented out of context, and at best, the plaintiff pointed to pretrial deposition testimony that configuration registers were “inside the chip[s] . . . everywhere.”

Lessons for Practice

It seems basic, but remember how means-plus-function claims work. The scope of your claim is the structure of what is disclosed in the specification. So when you’re drafting a means-plus-function claim you’re drafting to capture infringers who have the structure disclosed in your specification. When you are enforcing a means-plus-function claim, you need to prove that the accused product has that structure.