Leading smartphone wars patent analyst Florian Mueller wrote late last year about Apple's so called 'pinch to zoom' patent, which has been tentatively rejected in the first round of a re-examination process. The patent in question, US7844915, has a listed priority date of January 2007. In his blog, Mueller writes:

• Apple itself declared it the commercially most valuable one of the three multitouch software patents-in-suit, demanding a per-unit royalty for future (post-judgment) use of $3.10 while the other two software patents-in-suit are each valued at $2.02 per unit. 

• The prior art references underlying the (rejection on grounds of lack of novelty) is U.S. Patent No, 7,724,242 on a "touch driven method and apparatus to integrate and display multiple image layers forming alternate depictions of same subject matter". It doesn't specifically claim the pinch-to-zoom gesture as far as I can see, but it doesn't have to do that in order to serve as prior art, given that the '915 patent is only about one part (though an essential one) of the internal steps required to make pinch-to-zoom work. The other two prior art references (over the combination of which the '915 patent is deemed obvious) are the publication of a Japanese patent application (Japanese Pub. No. 2000-163031A, "Nomura") and this 1991 paper, entitled "The Automatic Recognition of Gestures" and authored by Dean Harris Rubine (Carnegie Mellon University).

US 7724242, by the way, discloses a pinch to zoom function for a touch sensitive display, whether  using a projector to display an image on the touch sensitive surface as shown in the figure below, or shown using 'thin profile display technologies...such as LCDs....'

But has all the prior art been found? This could be a good test for our new patent searching engine AmberScope.

This time of the year precludes a very elaborate analysis, but we can report from a preliminary evaluation using AmberScope, that the USPTO should add the following patents to the review process:

1) US8086971 Apparatus, Methods and computer program products providing finger-based and hand-based gesture commands for portable electronic device applications to Nokia, which discloses a pinch to zoom gesture (see Figure 8D, discussed in paragraph 46), and has a filing date of June 2006.

2) US2006/026521 Gestures for touch sensitive input devices to Apple, which extensively discloses a pinch to zoom function, and which has a priority date of July 2004.

Unlike the US 7724242 patent discussed by Mueller, both of these other prior art patents disclose touch sensitive displays for pinch to zoom.

In fact, the US patent office is aware of the Nokia patent (it is listed here), but I could find no reference to the 2006 Apple patent application as being listed prior art to the granted Apple "pinch to zoom" patent.