LEDdynamics Wins Summary Judgment in LED Tube Patent Suit


Altair Engineering, Inc. (Altair) is a Michigan-based product design and development company and the owner of U.S. Patent No. 7,049,761 (‘761 patent), entitled “Light tube and power supply circuit.”

The ‘761 patent is directed to a light tube for a fluorescent light fixure having a plurality of light emitting diodes (LEDs) within the bulb. 

Light tube (20) is illuminated by LEDs (22) packaged inside the tube.  The light tube (20) includes a cylindrically shaped bulb portion (24) having a pair of end caps (26, 28) at opposite ends of the bulb portion.


The LEDs are mounted on a circuit board (30).  The circuit board (30) and LEDs (22) are enclosed by the bulb portion (24) and the end caps (26, 28).

In 2007, Altair sued LEDdynamics, Inc. (LEDdynamics) in federal court in Detroit alleging that the Vermont LED maker’s Ever LED TR Tube Replacement (“TR device”) infringed the ‘761 patent.

Last month Judge George Caram Steeh granted LEDdynamics’ motion for partial summary judgment that the TR device does not literally infringe claims 3, 4, 16 and 17 of the ‘761 patent (altair_order.pdf).

As in most patent infringement suits, claim construction (where the court provides a legal interpretation of the relevant terms of the patent claims) was dispositive.  Independent claim 3 of the ‘761 patent recites “a plurality of closely-spaced light emitting diodes” inside the bulb portion of the light tube.

During the claim construction phase of the case, the court had intepreted the term “closely spaced” to mean:

not spaced-apart, such that adjacent LEDs are sufficiently close that another LED cannot fit in the space therebetween

A crucial piece of evidence in the case was a photograph showing that the accused TR device contains one-watt LEDs, each about a quarter of an inch wide, spaced 1.25 inches apart (i.e., enough space for another LED to fit in between).

Accordingly, the court found that LEDdynamics did not infringe the asserted claims of the ‘761 patent because in the TR device “it is clear that another LED may fit between adjacent LEDs.”

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Eric Lane

Eric Lane, the founder and principal of Green Patent Law, is an intellectual property lawyer and registered U.S. patent attorney in New York and is a member of the bar in New York and California. Eric has more than two decades of experience working with wind, solar PV, CSP, biofuels, and geothermal, energy storage technologies, carbon capture and sequestration, medical devices, data communications, mechanical, chemical, internet and software.