IP Law Daily PTAB properly rejected disputed claims of Cree patent on light-emission device
Monday, March 21, 2016

PTAB properly rejected disputed claims of Cree patent on light-emission device

By Mark Engstrom, J.D.

The Patent Trial and Appeal Board did not err in finding that six claims of a Cree Inc. patent on a light-emission device were obvious over a combination of prior art references, the U.S. Court of Appeals for the Federal Circuit has ruled (In re Cree, Inc., March 21, 2016, Bryson, W.). The decision of the Board was therefore affirmed.

Re-examination. In an ex parte reexamination of U.S. Patent No. 6,600,175, titled “Solid State White Light Emitter and Display Using Same,” a patent examiner rejected as obvious six patent claims that were added during the reexamination proceedings. According to the examiner, the patent was obvious under multiple combinations of prior art references, including the combination of U.S. Patent No. 3,691,482 (Pinnow), U.S. Patent No. 3,819,974 (Stevenson), and U.S. Patent No. 5,578,839 (Nakamura). The Board upheld the examiner’s rejection based on that and other combinations.

TTAB decision. According to the Board, Cree’s invention was nothing more than a “new application” of the high-power, high-brightness blue LED that was developed by Dr. Shuji Nakamura in 1993. The Board found that the new application was predictable in view of the state of the art in LEDs, the market demand for white-light devices, the finite number of identified means to convert light from LEDs into white light, and the advantages of using the down-conversion process.

Challenged claims. The claims at issue on appeal were directed to the production of white light by down-converting blue light from light-emitting diodes (LEDs). In one embodiment, a blue LED that was commercially available from Nichia Chemical was combined with three commercially available phosphors—a blue phosphor, a green-yellow phosphor, and a red phosphor—to produce light that was perceived as white.

“Known” in the prior art. On appeal, Cree argued that the Board had erred by assuming that it was “known” in the prior art how to make white light from a monochromatic LED through the down-conversion process. According to the court, Cree inferred that the Board’s use of the word “known” showed that the Board had erroneously concluded that a single prior-art reference disclosed the down-conversion from a blue LED light to a white light. The court, however, did not read the Board’s use of the word “known” in that way.

In context, the court explained, the Board did not use the word “known” to mean “disclosed in a single reference.” Instead, the Board’s statement that down-conversion was a “known” approach for creating white light from an LED was best understood to mean that persons of skill in the art were aware that down-conversion could be used to make white light out of blue light, regardless of the source of the light.

The Board found that the Pinnow reference taught a down-conversion process for creating white light that would work with blue light of any source, including the blue LEDs that were disclosed in Nakamura. In the court’s view, that conclusion was entirely reasonable in light of Pinnow. Therefore, the Board was correct when it said that it was “known” that white light could be created from LEDs using down-conversion, because Pinnow taught a down-conversion process that was understood to be equally applicable when it was used with an LED light source, as with the laser source that was specifically used in Pinnow.

Expert declarations. Cree argued that the Board concluded that down-conversion was “known” in the prior art because the Board had misread the declarations of Cree’s experts: Drs. Stringfellow, Redwing, and Wetzel. The court agreed with the Board that Cree’s experts had testified that down-conversion from a blue LED to white light was a known, albeit disfavored, process before high-intensity blue LEDs, such as those that were developed by Dr. Nakamura, became available.

Dr. Wetzel stated that the process of down-conversion was a “discredited” solution to the problem of generating white light from LEDs because energy and brightness were lost during the down-conversion process. Dr. Wetzel thus acknowledged that the down-conversion of LED light was “at least known” to those in the art, the court observed, in an admission that contradicted Cree’s argument that generating white light from blue LEDs was unknown.

Dr. Redwing stated in her declaration that the down-conversion of LED light “was known and had been used in very select and rare occasions.” She added, however, that down-conversion was not a practical source of white light because white-light applications required a significant amount of power and brightness, and “[l]ow illumination, as might be the case for an indicator light or a calculator, would clearly be insufficient for white light in th[o]se applications.” In the court’s view, Dr. Redwing’s discussion of the competing technologies clearly revealed that the process of down-conversion was a known method of creating white light prior to Cree’s patent.

Finally, Dr. Stringfellow’s testimony merely established that the use of down-conversion was not a preferred option for practical reasons. It did not show that down-conversion from LEDs was unknown (or that down-conversion could not have practical applications if a sufficiently powerful LED, such as the one that was invented by Dr. Nakamura, had been available).

Motivation to combine. Cree contended that neither the patent examiner nor the Board had proffered a rational motivation for combining the teachings of Pinnow, which disclosed the projection of a large, high-powered, gas laser beam through a modulator and a deflector and onto a phosphor screen to display a white image, with the teachings of Stevenson and Nakamura, which disclosed violet and blue LEDs.

Contrary to Cree’s contention, the Board provided a sufficient, non-hindsight reason to combine the references, according to the court. The Board found that a person of ordinary skill in the art would have realized that Nakamura (a brighter LED) was an upgrade over the LED of Stevenson, for use with down-conversion, and that the Nakamura LED would thus be suitable to produce white light based on the teachings of Pinnow. The availability of the high-powered Nakamura LED thus provided a motivation to combine Stevenson’s use of LEDs to create primary colors with Pinnow’s use of a short-wavelength light source to create white light.

Secondary evidence. Cree identified three categories of secondary evidence that the Board had, in Cree’s view, improperly discounted: (1) evidence of industry praise; (2) evidence of licensing; and (3) evidence of the commercial success of white LED products.

With respect to the evidence of industry praise, Cree identified two press releases from the Fraunhoffer Institute and argued that those documents supported an inference of non-obviousness. The press releases described the down-conversion of blue LED light to produce white light as a “breakthrough” and an “innovative idea,” the court observed, but the Board found that the documents were unpersuasive as secondary evidence because they praised the work of the Fraunhoffer Institute, not the work of the inventors of Cree’s patent. Self-serving statements from researchers about their own work did not have the same reliability as praise from others in the industry, the court observed.

For that reason, the court decided that the Board had permissibly concluded that the asserted press releases were unpersuasive as secondary evidence. In the court’s view, if the press releases showed anything, they showed that down-conversion was the “logical next step” after a high-power, high-intensity blue LED was developed by Dr. Nakamura.

With respect to the evidence of licensing, the court noted that affirmative evidence of a nexus to the patent was required when a license was proffered as evidence of commercial success. Although Cree submitted press releases to show that it had entered into multiple licensing transactions, it failed to show that the licenses were based on the merits of its patent, the court observed. In addition, the press releases showed that some of the licenses were broad cross-licenses or were intended to resolve litigation.

In light of the lack of specificity in the licensing evidence, the court decided that the Board had reasonably concluded that the asserted licenses were not shown to have a sufficient nexus to Cree’s patent to require a finding of non-obviousness.

With respect to the evidence of commercial success of white LED products, Cree proffered a declaration by Dr. Brandes, who proffered sales figures to show the market growth of white LEDs, and stated that, in his opinion, a nexus existed between the sales figures and the Cree patent. The Board found that Dr. Brandes’s declaration did not show a correlation between the claimed invention and the sales numbers. It also found that Dr. Brandes’s characterization of a nexus was “nothing more than an allegation or a conclusory statement.”

The court agreed with the Board that Dr. Brandes’s declaration merely repeated, in a conclusory fashion, that a nexus existed between the success of white LEDs and the claimed invention. Because the record was completely silent on whether the commercial success of white LEDs was caused by the subject matter of Cree’s patent, as distinct from the prior art, the court affirmed the Board’s conclusion that the evidence of commercial success did not outweigh the “strong prima facie showing of obviousness.”

Conclusion. In light of the foregoing facts and findings of record, the court upheld the Board’s decision to reject the disputed claims of Cree’s patent on a light-emission device.

The case is No. 2015-1365.

Attorneys: William F. Lee, Sydenham B. Alexander III, Peter M. Dichiara, Mark Christopher Fleming, Cynthia D. Vreeland, Brittany Blueitt Amadi, and Heather M. Petruzzi (Wilmer, Cutler, Pickering, Hale and Dorr, LLP) for Cree, Inc. Philip J. Warrick, Thomas W. Krause, Stacy Beth Margolies, and Robert J. McManus, U.S. Patent and Trademark Office, for USPTO Director Michelle K. Lee.

Companies: Cree, Inc.

MainStory: TopStory Patent FedCirNews

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