Produced by LESLYE DAVIS, CHARLES DUHIGG, AMY SCHOENFELD and XAQUÍN G.V.

During a patent lawsuit, judges and juries sometimes turn to a patent’s path through the U.S. Patent and Trademark Office to be sure that it was new, useful and not obvious at the time it was invented. A look at the history of three Apple patents involved in recent lawsuits shows some of the challenges faced by the patent office.

Patent #8,046,721 Slide to Unlock Unlocking a device by performing gestures on an unlock image. Patent History Pre-existing Patents The patent office used these patents to reject Apple's application, but ultimately decided that these did not cover "continuously moving a [single] unlock image along a predefined path." Nokia #7,453,443 Detects "touches on predetermined contact areas on the touch screen in a given order" to unlock the screen. Nokia #7,627,904 Objects are selected on a display to unlock a device. A signal is given to the user, such as light or sound. Asulab #7,286,063 A code is entered on a screen by touching a number and moving the finger over the glass to another number.

Patent #7,469,381 Rubber-banding List scrolling and document translation, scaling, and rotation on a touch-screen display. Patent History Pre-existing Patents This patent was not rejected, but an analysis of granted patents by M-CAM, a patent advisory firm, shows that some similar pre-existing patents could have been considered by the patent office. Microsoft #6,141,018 Offers "sophisticated animation" for scrolling text or images on the Web, such as bounce scrolling. Philips #7,152,210 User browses images by scrolling; speed of scroll varies with input and can shift to simulate inertia and friction. Hewlett-Packard #7,193,616 Allows handwriting on a page larger than the device; screen pans down one line when line’s end is reached.