Corning Cable Systems: When Backgrounds Backfire

Corning Cable Systems: When Backgrounds Backfire

This recent case of Corning Cable Systems LLC v. Canada (Attorney General) 2019 FC 1065 relates to whether information included in the Background section of a patent application can be cited in an obviousness objection as evidence of  what was the common general knowledge (CGK).

The two patent applications at issue relate to the use of Local Convergence Points (LCPs) which are adapted to distribute a signal supplied by a network service provider to units with multiple dwellings. An LCP is a housing or “box” containing a splitter module and optical fibers. The LCP receives a cable supplied by an internet service provider as an input and splits and distributes that cable to several units in a condominium, office building, hotel (and any other collection of subscriber locations that are in relatively close proximity to one another) to provide each dwelling with internet access.

Both proposed inventions employ “bend performance optical fibers,” which can be bent to a smaller radius than traditional fibers without incurring a marked loss in signal quality. Use of bend performance optical fibers, which are smaller in size, enables use of a smaller splitter module and allows the LCP to distribute a greater number of fibers and thus reach more subscribers. The independent claims in both applications listed specific dimensions, either to limit the size of the box or the density of the splitters.

Both applications were rejected by the Commissioner of Patents on the grounds of obviousness, in part because of an admission in the Background sections of both patent applications that “a need exists for LCPs that are cost-effective, are relatively small in size, and may be installed and maintained by relatively unskilled technicians”. The patent examiner took this admission to mean that this drive towards smaller sizes was common general knowledge at the time the invention was made. This meant that applying the “bend performance optical fibers” to satisfy this need was considered by the Commissioner to be an obvious development.

A key question in this case was therefore whether the Commissioner was right to interpret information in the Background section of the application as common general knowledge.

The Judge found that it was reasonable for the Commissioner to conclude that the problems identified in the applications are common general knowledge (CGK) of the person skilled in the art in part because:

  • CGK is a subset of the prior art, it must be discerned through a common sense approach; and
  • Since the background of a patent application may bind an applicant as prior art, it is reasonable for the Commissioner to consider general or broadly worded assertions of conventional practice to be binding as CGK (citing Newco Tank Corp v Canada (Attorney General), 2014 FC 287, confirmed on appeal).

This decision leaves ample room for discretion as to whether an admission in the background is necessarily considered common general knowledge. For example, the Judge took pains to note that it would not always be appropriate for the Commissioner to find that information presented in the specifications of a patent application is the common general knowledge of a person skilled in the art. In this case, it may well be argued that a drive towards smaller signal boxes, such as Local Convergence Points, would always be a general aim of the industry.

Nevertheless, this case serves as a reminder that, when drafting a patent application, it is important to ensure that the Background is limited to what is already publicly available information, and that any contribution, including the recognition of the problem to be solved, is included elsewhere (e.g. the Detailed Description or Summary sections).

Patent applications are an unusual genre of literature whose primary function is to facilitate the granting of a patent. It can be tempting for an inventor or patent agent to include, after listing the prior art and associated limitations, information showing what problem needs to be solved. Although this may seem like a good place for this information in order to help the document flow, it should be resisted because it may, as in this case, hinder the grant of a patent.

For more information, please contact William Murphy.


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