Means-Plus-Function: The Achilles’ Heel

| May 9, 2012

Noah Systems, Inc. v. Intuit, Inc.

April 9, 2012

Panel: Rader, O’Malley and Reyna. Opinion by Judge O’Malley


This decision illustrates that a patent could become invalidated even after surviving challenges of reexamination, which strengthen the presumption of validity, when a challenger discovers the Achilles’ Heel of a means-plus-function claim element resulting in a summary judgment of invalidity by the CAFC.   Noah appeals the granting, by the United States District Court for the Western District of Pennsylvania (DC), of Intuit’s Motion for Summary Judgment of Invalidity of USP 5,875,435 (the ‘435 patent) based on indefiniteness for a means-plus-function claim element without the DC hearing evidence of how one of skill in the art would view the specification.  The CAFC affirms by finding that the specification discloses no algorithm when the specification discloses an algorithm that only accomplishes one of two identifiable functions performed by the means-plus-function limitation.


Claim language

The ‘435 patent discloses an automated financial accounting system that allows an entity to connect to computers of other entities so that financial accounting information can be transmitted between them. Claim 12 at issue, recites:

means for (1) providing access to said file of said financial accounting computer for said first entity and/or agents of said first entity (2) so that said first entity and/or said agent can perform one or more activities selected from the group consisting of entering, deleting, reviewing, adjusting and processing said data inputs.

District Court

Both parties agreed that this feature of claim 12 is a means-plus-function limitation performed by a processor and that the language recited after the “means for” phrase constitutes the function.  Therefore, the specification of the ‘435 patent must contain an algorithm to perform the function.  However, the parties disagree as to what structure was disclosed in the specification to perform this function.  Intuit argued that the structure was indefinite because the specification disclosed no algorithm by which the computer was programmed to perform the claim function.  Noah argued that expert evidence regarding how one skilled in the art would view the specification needs to be considered before a conclusion on indefiniteness can be made.

A special master for the DC found that the specification disclosed no algorithm and therefore no structure, and concluded that the DC was not compelled to consider expert testimony, since it is only necessary to consider what one of ordinary skill in the art would readily understand from the specification when the sufficiency of the disclosed algorithm is at issue.  The DC adopted the finding of the special master and granted Summary Judgment of Invalidity.  

CAFC case law

In cases such as this one, involving a special purpose computer-implemented means-plus-function limitation, “this court has consistently required that the structure disclosed in the specification be more than simply a general purpose computer or microprocessor.”

In a means-plus-function claim “in which the disclosed structure is a computer, or microprocessor, programmed to carry out an algorithm, the disclosed structure is not the general purpose computer, but rather the special purpose computer programmed to perform the disclosed algorithm.”

Currently, CAFC case law regarding special purpose computer-implemented means-plus-functions claims is divided into two distinct groups: first, cases in which the specification discloses no algorithm; and second, cases in which the specification does disclose an algorithm but a defendant contends that disclosure is inadequate.

This distinction is important because the CAFC has clarified that, while “[i]t is certainly true that the sufficiency of the disclosure of algorithm structure must be judged in light of what one of ordinary skill in the art would understand the disclosure to impart,” in a situation in which the specification discloses no algorithm, “[t]hat principle … has no application…”.

CAFC analysis

The CAFC finds that there are two functions recited (1) providing access to the file (unlocking file function); and (2) once access is provided, enabling the performance of delineated operations on the file.

For the first function, the CAFC finds that the DC was incorrect, since an algorithm is provided in Fig. 1, col. 4, lines.47-56, and col. 6, lines 15-36 of the ‘435 patent for the first function, and this disclosure is sufficient to clearly link this structure with the “means” limitation.

Col. 4, lines 47-56 recites:

Next, line 27 leads to box 32 where passcodes are issued to approved interactive account user(s) and agent(s). Agents can include accountants, brokers or other financial advisors. The account user(s) can include the first entity as well as authorized users of the first entity, such as the controller or bookkeeper of a business. This access to the master ledger and subsidiary ledgers allows the agents to perform activities selected from the group consisting of entering, deleting, reviewing, adjusting and processing data inputs in the master ledger and subsidiary ledgers.

For the second function, the CAFC agrees with the DC that no algorithm is provided in the specification that enables the first entity and/or the agent perform one or more of the activities selected from the group consisting of entering, deleting, reviewing, adjusting and processing the data inputs.  Specifically, the CAFC focuses on box 44 in Fig. 1 and its corresponding disclosure in col. 6, lines 16-21, but finds this disclosure only concerns accessing the file (unlocking file function) and does not provide an algorithm for “enabling the performance” function.   Instead, this disclosure merely restates the function recited in claim 12.  Col. 6, lines 16-21 recites:

Line 41 then leads to box 44 where the access to the data inputs in the master ledger is set forth. This access can be provided to interactive users and agents of the first entity. At this box 44, change orders, recording instruction adjustments, manual transactions and the like can be entered by the agents or the interactive users.

Figure 1:

The CAFC reasons that while the specification discloses unlocking a file on a computer, the specification does not disclose a program for the computer to read and perform operations on the file.  The CAFC analogizes the present situation to a password protect Microsoft Word document.  “If the computer does not have a word processing program, the user cannot edit the file, even if he has the password to open it.”

The CAFC also finds that the specification, in col. 3, lines 26-32, makes it clear that some type of accounting software is required for the patented system to operate.   Specifically, col. 3, lines 26-32 recites:

It will be appreciated, however, that the central or host computer can be the individual entity’s personal automatic computing device (such as a personal computer or a telephone computing device) which can receive the data inputs and, in the case of a personal computer, for example, process the data inputs by using off-the-shelf accounting software. Therefore, even though the specification set forth herein will focus on a central or host computer, it will be appreciated that the above mentioned alternatives of a personal or telephone computer are contemplated by the invention.  (Emphasis added.)

The CAFC concludes that while the specification discloses that off-the-shelf accounting software can be used by the personal computer to process the data, the specification is silent as to how the central or host computer is to be programmed to allow processing of the data.  In other words, since no algorithm is provided for the central or host computer the specification fails to disclose any structure corresponding to the means-plus-function limitation; and therefore the means-plus-function limitation is a purely functional limitation.

The CAFC then finds that when the specification discloses an algorithm for less than all of the recited functions in the means-plus-function limitation, the disclosures must be analyzed as no algorithm being disclosed.

Prosecution Tip

Avoid using only means-plus-function limitations when the disclosed structure is a computer, or microprocessor, which performs the recited function.  Instead, a suite of different types of claims should be used.

Full Opinion

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