Friday, August 29, 2008

Patent Watch

Sun shines on recent solar cell patents and applications

The current (pun intended) problem with solar power is price and efficiency. The holy grail of the photovoltaic industry is solar cells priced at about $1 per watt and efficiencies of 30 percent or greater are desired. To date, these milestones have yet to be reached, but many companies and inventors are avidly working on new solar cell designs. Let’s take a look this month at solar energy patents naming New England inventors.

• Solar cell concentrators are used to focus sunlight on the photovoltaic cell to improve efficiency. Borrowing from LED fabrication techniques, Roger Welser of Providence, R.I.; Paul DeLuca, also of Providence, and William Roberts of North Attleboro are seeking a patent (No. U.S. 2008/0121269 published May 29, 2008) for a micro-concentrator lens made of epoxy encapsulating a solar cell chip. Fabrication costs are reportedly low. Also, when a solar cell chip is embedded in an epoxy lens with a higher index of refraction than air, a 50 percent reduction in semiconductor material can be achieved with a minimal loss in the field of view.

• Solar air-conditioning systems in general are not new but most use photo-electric collectors which are expensive and inefficient. James Boule of Mendon, Vt., invented a new solar air conditioning system using a less expensive and more efficient solar absorption coil. Boule’s pending patent application, No. U.S. 2008/0047285, was published Feb. 28.

• Most solar cells use silicon. Hollis, N.H., resident Eitan Zeira of Konarka Technologies Inc. in Lowell devised a polymer-based solar cell with a photovoltaic active layer described in pending patent application No. U.S. 2008/0011352 published Jan. 17. The active layer includes an “electrical tree” for transporting the free electrons, resulting in a more efficient solar cell.

• Konarka also won patent No. 7,329,709 on Feb. 12 for photovoltaic devices using fullerene compositions for the photoactive layer between the two electrodes of the photovoltaic. The inventors are Russell Gaudiana of Merrimack, N.H.; Savvas Hadjikyriacou of Tyngsborough; David Waller of Lexington; and Zhengguo Zhu of Chelmsford.

• The University of Massachusetts and the U.S. Army joined forces in producing patent No. 7,323,635 (Jan. 29) for flexible sheets of dye-sensitized solar cells manufacturable by roll-by-roll or sheet-by-sheet processes to be used in canopies for defense, commercial, residential, and agricultural applications. A conducting molecular cross-linking agent forms oxide bridges to semiconductor particles of the photovoltaic cell. The team of inventors includes Kethinni Chittibabu of Nashua, N.H.; Jin-An He of Lowell; Lynne Samuelson of Marlborough; Lian Li of Chelmsford; Sukant Tripathy (late of Acton); Jayant Kumar of Westford; and Srinivasan Balasubramanian of Woburn.

• Stephen Carlson of Cambridge is involved with organic photovoltaic cells and is seeking a patent via published patent application No. U.S. 2008/00115833 (published May 22) for an organic cell able to convert infrared as well as visible light into electricity. A polymeric organic radical cation compound is used in the infrared absorbing layer of the cell. Optodot Corp., located in Allston, is the assignee.

• Solasta Inc. in Newton is seeking a patent for photovoltaic materials including semiconductor nanocrystals with a band gap significantly smaller than the peak solar radiation energy to exhibit a multiple exciton effect in response to irradiation by solar radiation. Krzysztof Kempa of Billerica, Michael Naughton of Norwood, and Zhifeng Ren of Newton are listed in published patent application No. U.S. 2008/0178924 published July 31.

• Not all solar cell patents are high tech. Patent No. 7,350,692 (April 1) claims novelty in a mailbox with an LED interior light switched on when the mailbox door is opened and powered by a battery charged by a solar panel on the top of the mailbox. The lead inventor is Glen Bushee of Duxbury.

Kirk Teska is an adjunct law professor at Suffolk University Law School, and is the managing partner of Iandiorio, Teska & Coleman, an intellectual property law firm in Waltham. His book “Patent Savvy for Managers” is available online and in most major bookstores. He can be reached at kirk@iandorio.com.