Nano a Nano: Rivals Spar Over Quantum Dot Patents


Nanosys is a Palo Alto nanotechnology company specializing in high performance inorganic nanostructures, including quantum dots.  Quantum dots are nano-scale semiconductors that emit near-monochromatic light when subjected to light or electrical stimulation. 

Among the many applications of quantum dots are diode lasers, LEDs and solar cells, and Nanosys recently announced a new photovoltaics division called QD Soleil to focus on the solar field.

Nanosys is the exclusive licensee of several patents owned by the Massachusetts Institute of Technology relating to quantum dot technology.  These include U.S. Patent Nos. 6,861,155 (‘155 patent), 6,322,901 (‘901 patent), 7,125,605 (‘605 patent, 6,821,337 (‘337 patent) and 7,138,098 (‘098 patent).

Last month, Nanosys sued its Manchester, U.K. rival, Nanoco Technologies (Nanoco), and Nanoco’s U.S. distributor, Sigma-Aldrich (Sigma), alleging that their quantum dot technology sold under the brand name Lumidots infringes these patents (nanosys_complaint.pdf).

The asserted patents include two patent families: the ‘155, ‘901 and ‘605 patents are entitled “Highly luminescent color selective nanocrystalline materials” and are directed to nanocrystal particles having a semiconductor core and a semiconductor coating that emit light in a narrow spectral range.  The core consists of cadmium sulfur, cadmium selenium or cadmium tellurium, and the coating is zinc sulfur or zinc selenium.

The ‘337 and ‘098 patents, entitled”Preparation of nanocrystallites,” are directed to nanocrystallite manufacturing methods.  The ‘337 patent describes the method as follows:

The method includes contacting a metal, M, or an M-containing salt, and a reducing agent to form an M-containing precursor, M being Cd, Zn, Mg, Hg, Al, GA, In or Tl.  The M-containing precursor is contacted with an X-donor, X being O, S, Se, Te, N, P, As, or Sb.  The mixture is then heated in the presence of an amine to form the nanocrystallite.

The lawsuit was filed in the U.S. District Court for the Western District of Wisconsin, and Nanosys is requesting compensatory damages and a permanent injunction against Nanoco and Sigma.

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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.