Cree and Boston University Settle LED Patent Suits with Bridgelux

January 28th, 2009 by Eric Lane Leave a reply »

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A patent dispute that had been raging in three jurisdictions came to an end last month, when Durham, North Carolina LED maker Cree and Boston University (BU) settled with Sunnvale, California based LED solutions provider Bridgelux.

The lawsuits started in 2006, when Cree and BU sued Bridgelux, alleging infringement of patents relating to LED technology.  The patents included U.S. Patent No. 6,657,236 (’236 patent), owned by Cree, and U.S. Patent no. 5,686,738 (’738 patent), owned by BU and licensed by Cree.

The ’236 patent is directed to LEDs having light extraction structures, which boost efficiency by reflecting, refracting or scattering light so that more light escapes the LED. 

The ’738 patent relates to a method of preparing highly insulating gallium nitride (GaN) monocrystalline films in a molecular beam epitaxial growth chamber using a process called epitaxy (depositing a monocrystalline film on a monocrystalline substrate).  GaN is important because it can emit light that is on the edge of the UV-visible region.

Cree and BU asserted the ’236 and ’738 patents along with a few other patents in courts in Winston-Salem, North Carolina, Lufkin, Texas and San Francisco, California.  Bridgelux accused Cree of infringing one of its patents – U.S. Patent No. 6,869,812, directed to an LED chip with a transparent substrate and an elongated aspect ratio – but by and large Cree was on the offensive in these cases.  The North Carolina case was dismissed in 2007 on jurisdictional grounds.

One interesting thing about this dispute is that Cree handily won the claim construction phase of the California case (claim construction is where the court interprets the legal scope of the patent terms; this step is crucial to infringement cases and can lead to settlement if one party does well).

In claim construction, the patentee generally argues for broad interpretations to sweep more accused devices into the purview of the asserted patents, while the accused infringer asserts narrow constructions to avoid infringement liability.  In the California claim construction order (nd_cal_claims_order.pdf), the court adopted Cree’s broader constructions of almost all of the disputed claim terms.

For instance, the parties disputed whether the term “adjacent” in the ’236 patent claims means the structures are near each other (Cree’s position) or must be in direct physical contact with each other (Bridgelux’s position).  The court held the term means near each other because the patent allows for two “adjacent” layers to sometimes be separated by an intermediate layer.

In addition, the term “layer” was construed to mean “a defined thickness that is part of a material” (Cree’s position) instead of Bridgelux’s narrower interpretation of it as “a film made of a specific composition of chemical elements and a specific doping concentration.” 

Even the term “on” was decided in Cree’s favor to mean “positioned indirectly or directly above” instead of “positioned in direct contact with” as Bridgelux proposed. 

Bridgelux has taken a license to the patents at issue, and the parties have entered into a supply agreement so Cree will become a significant supplier to Bridgelux.

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