Federal Circuit Upholds Validity of Philips Patent on Dimmable LEDs

  • The Patent Trial and Appeal Board recently decided that a Philips patent on dimmable LED technology is valid despite a challenge from a competitor. That decision was later affirmed by the U.S. Court of Appeals for the Federal Circuit.
  • The patent at issue has been well-litigated, with Philips asserting the patent against numerous competitors in federal courts and at the U.S. International Trade Commission.

A patent directed to dimmable LED technology was upheld as valid in an appeal to the U.S. Court of Appeals for the Federal Circuit. The patent is owned by Philips Lighting North America Corporation, a subsidiary of Dutch consumer product giant Koninklijke Philips N.V. The Federal Circuit’s decision marks the unsuccessful conclusion of a challenge to the patent’s validity brought by a competitor of Philips Lighting called Wangs Alliance Corporation, which does business under the name WAC Lighting.

Philips Lighting has used the patent – U.S. Patent No. 7,038,399 – over the past several years to sue at least six competitors for patent infringement. Last fall, Philips Lighting also brought a case at the U.S. International Trade Commission seeking to prevent at least ten other competitors from importing allegedly infringing LED products into the United States.

The application that led to the patent was filed in 2003. The application explains that the lighting industry was having trouble making increasingly-popular LED lighting products compatible with existing dimmer switches. This trouble was caused by the fact that LED lights typically use direct current (DC) power, whereas dimming switches for conventional lighting use alternating current (AC) power. AC dimmers operate by modifying the waveform of the alternating current and thus reducing average voltage applied to the light. Since LED lights need a steady power input (i.e. there is no “waveform”), the existing dimmers did not function properly if an LED light was used in a conventional system.

Philips Lighting claimed to have solved this problem by adding circuitry to an LED light that would convert the modified AC waveform into an adjusted, steady power input. This solution would allow an LED light to have its intensity adjusted through the use of a conventional AC dimmer. The U.S. Patent and Trademark Office reviewed the Philips Lighting application and agreed that the invention was new and non-obvious when compared to existing technology. As a result, the ‘399 Patent issued in 2006.

The dispute with WAC began in May 2014, when Philips Lighting brought a complaint in federal court in Massachusetts alleging that WAC’s products sold under the LEDme®, dwelLED™, and InvisiLED® brand names infringe the ‘399 Patent. Those products include a wide range of LED lights, including those for ceiling, recessed, track, spotlight, vanity, and outdoor mounting. In the complaint, Philips Lighting requested that the court enjoin WAC from further infringement and award monetary damages.

After being sued for patent infringement, WAC challenged the validity of the ‘399 Patent at the Patent Trial and Appeal Board. If a party can prove in court or at the Board that a patent is either not new or is an obvious improvement to existing technology, the patent can be canceled as invalid and the related lawsuit would likely be dismissed. WAC argued at the Board that the invention of the ‘399 Patent was obvious. As evidence, WAC submitted two documents as evidence of the state of technology at the time the ‘399 Patent was filed in 2003: a document called “Hochstein” that describes the control system for an LED traffic light, and a document called “Bogdan” that describes a dimmer switch for use with fluorescent and halogen lights. WAC argued that combining Hochstein and Bogdan would reveal the invention of the ‘399 Patent, and thus the ‘399 Patent was invalid as obvious.

Responding to WAC’s accusations of obviousness, Philips Lighting used a common tactic on the part of a patent owner by providing a highly-technical argument that Hochstein and Bogdan could not be combined. At a high level, the Philips Lighting argument noted that it would not make sense to combine the AC-power dimmer switch of Bogdan (designed for fluorescent and halogen lights) with the DC-power traffic light of Hochstein (designed with LED lights).

The Board agreed with Philips Lighting, and decided that the ‘399 Patent was valid even when considering Hochstein and Bogdan. WAC then appealed that decision to the Federal Circuit. (That’s right, the same parties have now litigated the ‘399 Patent in three different forums: the federal district court, the Board, and the Federal Circuit).

A panel of three appellate judges at the Federal Circuit received briefing and oral arguments on the question of whether it would make sense to combine Hochstein and Bogdan. After hearing all the evidence from both parties, the panel issued a one-sentence decision that affirmed the Board’s decision and thus affirmed the validity of the ‘399 Patent.

Although WAC has the option of appealing the Federal Circuit’s decision to the Supreme Court, the case will likely head back to the federal court in Massachusetts. Once there, Philips Lighting and WAC will likely attempt to settle the case or proceed to trial on the question of whether WAC’s products infringe the ‘399 Patent.




Note: The Federal Circuit decision also upheld the validity of Philips Lighting’s U.S. Patent No. 7,352,138. The case is Wangs Alliance Corporation d/b/a WAC Lighting Co. v. Philips Lighting North America Corporation, Case No. 17-1531 (Fed. Cir. Mar. 14, 2018).

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