Mixing Function and Apparatus Elements in a Patent Claim Creates Invalid Claim

The Court of Appeals for the Federal Circuit affirmed a summary judgment for invalidity due to indefiniteness under Section 112 ¶ 2 because patentee’s apparatus claim included a method step. Rembrandt Data Tech. LP v. AOL, LLC, Case No. 2010-1002 (Fed. Cir. April 18, 2011) (available here).

Patentee Rembrandt’s apparatus claim covered a data transmitting device or modem using a data processing algorithm but the apparatus claim ended with an element “transmitting the trellis encoded frames” which did not include the Section 112 ¶ 6 prefatory “means for” language. Rembrandt argued that the court should amend or construe the “transmitting” claim limitation to be a “transmitter section for” which, if approved, would bring the claim limitation within the scope of the statutory “means plus function” provisions of 35 U.S.C. § 112 ¶ 6. The Federal Circuit, in affirming the trial court’s finding of invalidity due to claim indefiniteness under § 112, rejected Rembrandt’s claim revision argument and “held that ‘reciting both an apparatus and a method of using that apparatus renders a claim indefinite under Section 112, paragraph 2.’” Rembrandt, slip opn. pg. 15, citing IPXL Holdings, L.L.C. v. Amazon.com, Inc., 430 F.3d 1377, 1384 (Fed. Cir. 2005) and Ex parte Lyell, 17 U.S.P.Q.2d 1548 (B.P.A.I. 1990).

The Patent Statute permits a patentee to use “functional method” language in an apparatus or system claim to cover structural items performing the function if those items are adequately described in the patent specification. “An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.” 35 U.S.C. § 112 ¶ 6.

In general, Rembrandt’s claim covered a modem. A modem is “a communications device that enables a computer to transmit information over a standard telephone line.” The ’236 patent, entitled “Fractional Rate Modem with Trellis,” describes a modem utilizing both the “fractional rate encoding” technique for more rapidly transferring data and the “trellis encoding” technique for reducing errors in data transmission. (patent available here).

The Court’s attention was directed to claim 3. The first four elements of claim 3 of the ’236 patent recite apparatus elements: buffer means, fractional encoding means, second buffer means, and trellis encoding means. The final element is a method: “transmitting the trellis encoded frames.” Claim 3 of the ’236 patent reads:

3. A data transmitting device for transmitting signals corresponding to an incoming stream of bits, comprising: first buffer means for partitioning said stream into frames of unequal number of bits and for separating the bits of each frame into a first group and a second group of bits; fractional encoding means for receiving the first group of bits of each frame and performing fractional encoding to generate a group of fractionally encoded bits; second buffer means for combining said second group of bits with said group of fractionally encoded bits to form frames of equal number of bits; trellis encoding means for trellis encoding the frames from said second buffer means; and transmitting the trellis encoded frames.

’236 patent col.6 ll.1-24, (emphasis added).

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