Microsoft's complaint against Barnes & Noble's Android-based Nook devices has been narrowed down to just three patents, with the US International Trade Commission having to decide whether Nook devices infringe on several patented methods of interacting with and downloading electronic documents. Barnes & Noble is also asking the ITC to declare the patents invalid because they cover obvious and trivial functionality.

Microsoft's ITC complaint, which was filed in March 2011 and targets Foxconn and Inventec in addition to Barnes & Noble, cited five patents. One 1994 patent related to "new varieties of child window controls [that] are provided as system resources that application programs may exploit," and a 1997 patent related to how browsers load and display content in portable computers with limited display areas have since been dropped from the case.

An ITC staff attorney revealed Monday that he is recommending a ruling stating that Barnes & Noble did not infringe the three remaining Microsoft patents, but a final decision is not scheduled to be revealed until April 27. The ruling will be an important one in Microsoft's quest to extract money from every Android hardware vendor. Samsung, HTC, Acer, LG, and others have signed patent licensing agreements with Microsoft. Amazon—which uses Android for its Kindle Fire tablet but not for the Kindle e-readers—signed a patent agreement with Microsoft in February 2010 which includes a license to one of the patents being asserted by Microsoft against Barnes & Noble.

Other than Barnes & Noble, the lone major device maker refusing to join what Microsoft calls its "Android licensing program" is Motorola Mobility, which holds 17,000 patents of its own and is in the process of being acquired by Google.

Barnes & Noble has accused Microsoft of demanding excessively high licensing fees. While the bookseller lost a "patent misuse" claim it filed against Microsoft, it can still win the day by either proving the patents were wrongly issued or that Nook devices do not infringe them. Microsoft's complaint centers on the Nook and Nook Color, and seeks to block imports of the devices into the United States.

With that in mind, let's take a look at the three remaining patents Microsoft is asserting in its claim against Barnes & Noble. One discusses a method of letting users annotate read-only documents, another describes a method for highlighting and selecting elements of electronic documents, and a third covers a method for browsers to quickly download documents from a remote computer network. Barnes & Noble has called all the patented features "insubstantial and trivial."

Patent #6,957,233: Making annotations in read-only documents

This patent, filed in December 1999 and issued in October 2005, is the one already licensed to Amazon for use in its Kindle e-readers. Long before there were Kindles and Nooks, Microsoft's patent filing observed that an inability to annotate read-only documents could hamper the electronic publishing industry. The patented Microsoft technology solves the problem with "A system and method for capturing annotations for a non-modifiable document. Once it is determined that an annotation is to be created, the system determines the file position of the selected object. The file position of the selected object is stored along with the created annotation in another file or a non-read only portion of a file storing the document. Using the file position, the annotation may be properly identified with the selected object without modifying the non-modifiable document."

In its March complaint against Barnes & Noble, Microsoft says it uses this patented technology in Windows Phone 7, and provided screenshots demonstrating how the Nook Color's system for annotating electronic books allegedly violates the patent. The Nook Color lets users select text from read-only portions of a document and add notes to the selected text, while storing the position of the annotation and the annotation itself "separately from the non-modifiable portion of the file," and then making the annotations available to the user in a secondary display area. This technology is a patent violation, according to Microsoft.

While not all of the ITC case documents have been made public, Barnes & Noble's defense can be gleaned from an April 25, 2011 filing from a corresponding case in US District Court in Seattle. "The Nook and Nook Color do not infringe any valid claim of the [five patents cited by Microsoft]," Barnes & Noble stated, "and none of these trivial features serve as a basis for customer demand for these products. The subject matter embraced by the... patents was not new and would have been highly obvious at the time those patents were filed."

With respect to the patent on annotations in read-only documents, Barnes & Noble says it was improperly issued because Microsoft failed to disclose prior art from a European patent to the US patent office. "In implementing the concept of annotating non-modifiable documents, Microsoft did not have to devise any unique solutions, but merely applied well known techniques to the problem created by the advent of electronic publishing," Barnes & Noble wrote. "This was nothing more than the utilization of common sense solutions to a problem, and there is nothing patentable about the concepts allegedly covered by this patent."

Patent #6,891,551: Highlighting and selecting elements of electronic documents

This patent, which Microsoft filed in January 2001, covers "A computer system and method for highlighting and selecting elements of electronic documents.... In one embodiment, a selection area identifies an initial selection of data, and one or more selection handles appear on the selection area to allow dynamic resizing of the selection area to select a larger or smaller portion of data or number of items."

While the previous patent we discussed talks about methods for annotating documents, this one covers the process of highlighting the text onto which readers would add highlights and notes. By allowing users to select text, and then increase or decrease the amount of text selected by dragging "graphical selection handles" in the form of two vertical bars positioned at the beginning and end of the selection area, Barnes & Noble violates the patent, Microsoft says. The patent covers both touch-sensitive displays and other types of inputs, like a mouse or trackball, and references Microsoft's implementation of the technology in Windows-based tablet PCs.

Barnes & Noble, however, states that "the simple act of using handles for their very purpose—changing the size of selections—was neither novel nor non-obvious" at the time the patent was issued. Further, Barnes & Noble denies that Nook devices include handles with the functionality described in the patent itself.

Patent #5,778,372: Quickly downloading documents from a browser

Filed in 1996 when the Internet was a much different beast than it is today, this patent covers browser technology that allows faster viewing of downloaded documents by displaying viewable portions of the document before the download is completed. "For enhancing responsiveness, the browser initially displays an electronic document without a background image so that the electronic document is initially displayed more quickly," the patent sates. "The browser also prioritizes downloading of embedded images of the document by their incorporation in the currently visible portion of the electronic document. Further, the browser dynamically creates additional connections for retrieving resources incorporated into the electronic document from the remote computer network."

In its complaint, Microsoft notes that Nook devices have a pre-installed Web browser, which "draws an initial display" of a webpage without a background image before issuing a second request for the image. "After the background image is received from the remote server, the webpage is redrawn by superimposing the webpage contents over the background image," Microsoft states. Although this seems like a rather basic capability; the browser's act of making a separate request to retrieve the background image and its ability to display the page in a basic form before receiving the image is the key in Microsoft's infringement claim.

Barnes & Noble denies that Nook devices infringe the patent, and seems to indicate that removing similar functionality from modern devices wouldn't harm the user experience. "The patent refers to perception of slow displays involving background images that existed with typical Internet connections and processors at the time of filing (i.e. 1996)," Barnes & Noble states. The patent "describes displaying text and then redisplaying the text again after the background image loads. While this duplicative display may have had some use in the 1990s, it has no value for the connectivity and processors of today used by the Nook and Nook Color devices."

Can Barnes & Noble prove the patents are invalid?

While Barnes & Noble denies violating Microsoft's intellectual property, the company's main argument seems to be that the "the patents themselves are invalid," IP attorney Patrick Patras of Hinshaw & Culbertson LLP in Chicago, who has represented Hitachi and others in patent lawsuits, tells Ars.

Patents carry a presumption of validity making them difficult to overturn. But there are factors seemingly going in Barnes & Noble's favor. The ITC staff attorney's recommendation that Barnes & Noble get a favorable ruling is not binding, but it is a good sign, Patras said.

"The staff attorney is really acting as an independent third party in the litigation whose job is to protect the public interest," Patras said. "The fact you've got this independent third party who is sophisticated in patent matters, who has apparently reached the conclusion that Barnes & Noble should win, I think that speaks volumes."

Further, Barnes & Noble's argument that the patents themselves are invalid is likely to get a better hearing in front of an ITC administrative law judge than in front of a jury, Patras believes. "Invalidity must be proven by clear and convincing evidence, which typically is said to be pretty difficult to do," he said. "I suspect it's more difficult to persuade a jury to find a patent invalid than it would be to persuade an administrative law judge to find a patent invalid."

While the Barnes & Noble case is being decided long after most Android-using device makers settled with Microsoft, a decision in Barnes & Noble's favor could make it harder for Microsoft to obtain licensing fees from other vendors going forward. Microsoft is, presumably, putting some of its best patents forward in the case. This case may not be representative of all other Android litigations, because many patents are specific to smartphones, but a ruling that the patents are invalid would be a blow for Microsoft nonetheless.

"I think other parties that were approached by Microsoft would probably feel a little bit more confident in standing up to Microsoft in fighting for a better deal," if Barnes & Noble were to win, Patras said. "If they're found to be invalid or not infringed by Android, in a sense Microsoft then is going to have to rely on what they themselves view as less good patents."