Tuesday, November 17, 2009

Careful when using OR in a claim to modes

The Ex parte Nguyen decision which I discussed earlier (here) had an interesting footnote about the use of "or." The claim limitation at issue was "a single button for controlling said means for operating to allow a said user to select write mode or said pan mode." Other limitations described the two modes.

The concept of modes and mode selection is common in the kinds of applications I draft and prosecute. Modes are almost always mutually exclusive, so the system is in one of the supported modes at a time. Therefore, using "or" when describing mode behavior seems natural to me, and I would interpret the above limitation as a button that selects between the two modes.

The Board's footnote in Nguyen suggests that the Board would interpret this limitation differently:
We note that the "single button" of claim 1 also reads on a button that merely selects either a write mode or pan mode, i.e., not necessarily both.
I read this as "a button that selects write mode reads on the claimed button; a button that selects pan mode reads on this button; the button doesn't have to toggle between the two." Whereas my interpretation of the claimed button does require the button to toggle between the two.

This is the first Board decision I recall that suggested this interpretation, but I've definitely run across Examiners who treat the phrase "X or Y" as permission to find only one of them in the reference. You can try to convince the Examiner (or the Board) that "or" doesn't always have such a narrow meaning, but I think this claim language might work better: "a single button for controlling said means for operating to allow a said user to select BETWEEN said write mode AND said pan mode."

One weakness I can see with my proposed claim language is this: what if there modes other than write and pan? Will the accused infringer attempt to argue that your claim requires switching between exactly these two modes?


  1. I suspect that the Board interpretation may have been made in the context of the "on-screen icon" under debate. While two different icons can be used to select the two modes (write and pan), obviously, a single icon cannot be used as a multi-mode switch i.e. greater than two modes. (If used for selection between ONLY two modes the "inactivated" state of the icon will correspond to one of the two modes.)
    Of course, the bad news is that some Examiners reading the Board decision will be tempted to generally treat other OR conditional statements in this "devious" manner.
    On the other hand, if the invention is truly directed at a "manually actuated button" the claim wording may be changed to indicate that the write mode is selected by placing the button in a first state/position, and the pan mode is selected by placing the button in a second state/position (thereby tying both selections (via the state/position wording), to one single button). Incidentally, the wording would not preclude the button from being used to select additional modes.

  2. reading your posts enlighten me a lot on patent practices. I have bookmarked your blog.

    I have a suggestion to reword the claim in addressing the "weakness" you pointed out:

    ............ BETWEEN MODES THAT INCLUDE said write mode AND said pan mode."

    since "include" is not exhaustive. just my two cents

  3. @Draco: Thanks for commenting. Yes, I agree your rewording addresses the weakness in my original.

  4. the other way the above can be written is this:

    "select between at least one of a write mode and the pan mode"

    This helps not putting a restriction on just two modes as you mentioned in the draft. What do you think?

  5. >"select between at least one of a write mode
    >and the pan mode"

    You've moved from the plain English way of expressing alternatives (OR) to the tortured claim way of expressign alternatives (AT LEAST ONE OF ... AND).

    I don't think that change helps.

    But you're also reword to say "select BETWEEN". That makes the difference. The first commenter (Draco) made the same suggestion.