Three new light emitting diode (LED) patent infringement suits were filed last month, all in the Eastern District of Texas in Marshall.

In the first case, Japanese LED maker Nichia Corporation (Nichia) has accused Chinese solar products company Jiawei North America Inc. (Jiawei) of infringing four patents relating to LED technology.

According to Nichia’s bare bones complaint (nichia_complaint.pdf), Jiawei is infringing U.S. Patent Nos. 5,998,925 (‘925 Patent), 7,026,756 (‘756 Patent), 7,531,960 (‘960 Patent) and 6,870,191 (‘191 Patent).  The ‘925, ‘756 and ‘960 Patents are members of the same patent family.

The three related patents describe a light emitting diode (100) that minimizes deterioration in emission light intensity by including a phosphor in the coating resin (101) that covers the light emitting component (102).  The ‘756 Patent claims a garnet fluorescent material activated with cerium as the phosphor.

According to the ‘756 Patent, incorporating a phosphor in the LED reduces deterioration:

the phosphor used in the light emitting device has excellent resistance against light so that the fluorescent properties thereof experience less change even when used over an extended period of time while being exposed to light of high intensity.  This makes it possible to reduce the degradation of characteristics during long period of use and reduce deterioration due to light of high intensity emitted by the light emitting component . . . to provide a light emitting device which experiences less color shift and less luminance decrease.

In two lawsuits filed the same day, Light Transformation Technologies LLC (LTT), exclusive licensee of U.S. Patent No. 6,543,911 (‘911 Patent), has accused a host of lighting and electronics companies of infringing the ‘911 Patent.

One complaint (ltt_complaint1.pdf) lists 15 defendants including LEDdynamics, Philips, Osram Sylvania and Volkswagen.  The other complaint (ltt_complaint2.pdf) names Alliance Electronics and several others. 

The accused products include lenses, optics, lighting products and automobile lights that either allegedly infringe the ‘911 Patent or are designed for use with allegedly infringing products. 

The ‘911 Patent is entitled “Highly efficient luminaire having optical transformer providing precalculated angular intensity distribution and method therefore.”  The central innovation of the ‘911 Patent is an integrated omnidirectional light transformer (100) that includes an optical window (110) and a support (120).   

The light transformer (100) may have an aspherical reflective surface (130) and be incorporated into lighting assembly or luminaire (300) along with a light source (310), a shell (320), a connector (330) and a printed circuit board (340).  The light source (310), which may be an LED, emits light rays (350, 352) that are reflected in accordance with the curvature of the reflective surface (130). 

According to the ‘911 Patent, this design results in luminaire (300) having a luminous intensity higher at lower angles, and all light emitted by the light source will be directed in a predetermined pattern. 

In particular, the luminaire 300 can redirect the light so that illuminance at a long range distance (i.e. at the lower observation angles) will be equal to illuminance at a short range distance (i.e. at the higher observation angles).  Therefore, as a driver in a car approaches the luminaire 300, the driver can perceive light of equal intensity at long distances and at short distances from the luminaire 300.

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