Archive for June, 2008

Epistar Takes a License from LED Professor

June 3rd, 2008

Retired Columbia University professor and LED innovator Gertrude Neumark Rothschild has reached her fourth settlement of patent infringement claims, this time with Epistar (the other licensees are Toyoda Gosei, Osram and Philips Lumileds, which I wrote about in a previous post).  She had accused the Taiwanese technology company of infringing two of her patents, U.S. Patent Nos. 4,904,618 and 5,252,499.

The patents relate to methods of doping semiconductors, which means adding impurities to increase the number of free charge carriers.  Rothschild’s patented process made high spectral range LEDs, such as blue and green, commercially feasible.  Under the terms of the agreement, Rothschild granted Epistar a worldwide license to use the technology in the patents.

This agreement was not the result of litigation and was announced by Rothschild’s counsel.  But other litigation over these patents continues, with a suit pending in federal district court in New York against semiconductor maker Cree Inc. and an International Trade Commission (ITC) investigation into possible infringement by more than 25 companies, including Sony, Toshiba, Motorola and Samsung. (see my previous post the ITC case)

The Hymotion High Mileage Prius Plug-In Conversion Module

June 1st, 2008


Battery maker A123 Systems (A123) just started selling its L5 Hymotion Plug-in Conversion Modules, which can transform the Toyota Prius into a plug-in vehicle capable of getting up to 100 mpg for the first 30-40 miles of driving.  The L5’s high energy capacity lithium ion batteries supplement the vehicle’s battery and allow the Prius to use its electric drive more often and for longer distances.  More frequent periods of all electric driving translate into better fuel efficiency. (read the Ecogeek piece and green tech gazette article on the L5)

A123 calls the Hymotion technology Nanophosphate, which means the batteries use lithium iron phosphate as cathode material.  Several of A123’s patents and applications cover lithium iron phosphate batteries, including U.S. Patent No. 7,348,101, U.S. Patent No. 7,261,979 and U.S. Application Pub. No. 2007/0166617. 

A123’s patented battery technology reduces the amount of time necessary for charging and loses relatively little capacity and power over numerous charge/discharge cycles, an important advantage for applications that need high power for long periods of time, such as motor vehicles.  Specifically, one problem with rechargeable batteries is that relatively high charge rates (i.e., less than half an hour) typically cause growth in impedance (resistance and voltage drop). 

Impedance can lead to lithium plating, a film formation on the surface of the negative electrode materials which consumes some of the active lithium from the battery and results in a loss of capacity.  The materials used by A123, including lithium iron phosphate, achieve low impedance growth.  The resulting batteries don’t have the problem of lithium plating and therefore maintain higher power capacities over time, enabling the highly efficient Prius to be even more efficient.