Our Green Off-Patent Report provides selected highlights of green patents which have completed their 20-year terms and recently expired or will complete their terms and expire within the next week or so (assuming the patentee paid all requisite maintenance fees; U.S. patents require payment of fees 3 1/2, 7 1/2, and 11 1/2 years after issuance to stay in force).
Many of the green technologies in use today are off-patent, i.e., the patents covering the technologies have run their 20-year term and expired.Â
Knowing which technologies are off-patent is important because those technologies are in the public domain and can be exploited by anyone. It’s also interesting because it provides a window into what was cutting edge technology twenty years ago.
The green off-patent searching is performed by Cleantech PatentEdgeâ„¢.
U.S. Patent No. 5,411,767, entitled “Method for producing interconnector for solid electrolyte type fuel cell” and directed to a method for producing interconnectors for electrically connecting unit cells of a solid electrolyte type fuel cell wherein an interconnector material such as a perovskite complexed oxide is thermally sprayed onto the surface of an electrode of a solid electrolyte type fuel cell by a plasma thermal spraying process. Filed September 8, 1992; issued May 2, 1995; expired September 8, 2012.
U.S. Patent No. 5,406,154, entitled “Power unit for motor vehicles” and directed to a power unit for a motor vehicle having an electric motor including a heat sink detachably connected to a motor case, switching elements for switching an electric current to be supplied to the electric motor, a cover member for the switching elements, and resin to fix the heat sink to motor case. Filed September 2, 1992; issued April 11, 1995; expired September 2, 2012.
U.S. Patent No. 5,388,025, entitled “Rechargeable electrical energy storage device having organometallic electrodes” and directed to a rechargeable electrical energy storage device comprising an electrochemical cell having two electrodes constructed of a similar organometallic compound whereby the electrodes are electrically connected by an ion carrying electrolyte and physically separated by a barrier that will pass the ions but not electrons. Filed September 1, 1992; issued February 7, 1995; expired September 1, 2012.
U.S. Patent No. 5,355,747, entitled “Flywheel assembly” and directed to a flywheel assembly comprising a first flywheel connectable to an engine, a second flywheel, and an inter-flywheel viscous damping mechanism providing viscous damping of flywheel torsional vibrations. Filed September 1, 1992; issued October 18, 1994; expired September 1, 2012.
U.S. Patent No. 5,340,665, entitled “Creep resistant, metal-coated LiFeO2 anodes for molten carbonated fuel cells” and directed to a porous, creep-resistant, metal-coated, LiFeO2 ceramic electrode for fuel cells useful for molten carbonate fuel cells and solid oxide fuel cells. Filed September 3, 1992; issued August 23, 1994; expired September 3, 2012.
U.S. Patent No. 5,334,259, entitled “Amorphous silicon solar cell and method of manufacture” and directed to a method of amorphous silicon solar cell manufacturing comprising forming thin films of a transparent electrode material, amorphous silicon, and a backside electrode on a transparent substrate, using an alkali resistant metal for the backside electrode, and employing wet-etching to open holes that penetrate through the backside electrode and amorphous silicon layers. Filed September 10, 1992; issued August 2, 1994; expired September 10, 2012.
U.S. Patent No. 5,327,991, entitled “Exhaust gas purifying method and apparatus for a hybrid car” and directed to an exhaust gas purifying apparatus for a hybrid car wherein the internal-combustion engine is equipped with a catalyst installed in an exhaust pipe for purifying exhaust gas and a heater for heating the catalyst under the control of the controller to enhance its catalytic action. Filed September 2, 1992; issued July 12, 1994; expired September 2, 2012.
U.S. Patent No. 5,316,592, entitled “Solar cell roofing assembly” and directed to a solar roofing assembly comprising a roofing membrane, a plurality of insulation blocks disposed as a continuous layer on top of the roofing membrane, and a plurality of photovoltaic modules directly on top of the insulation blocks, whereby the photovoltaic modules serve as ballast for the insulation and membrane layers. Filed August 31, 1992; issued May 31, 1994; expired August 31, 2012.
U.S. Patent No. 5,314,072, entitled “Sorting plastic bottles for recycling” and directed to an apparatus and method for sorting plastic bottles for recycling by parameters such as whether the bottle is clear, colored, contains chlorine, and has a small or large diameter. Filed September 2, 1992; issued May 24, 1994; expired September 2, 2012.
U.S. Patent No. 5,300,373, entitled “Electrochemical cell stack and method of making an electrochemical cell stack” and directed to an electrochemical cell stack made from a continuous laminate web fan-folded into a stack and including an electrode layer, an electrolyte layer, and a plurality of discrete opposite polarity electrode segments connected by current collector strips.  Filed September 11, 1992; issued April 5, 1994; expired September 11, 2012.Â
U.S. Patent No. 5,296,045, entitled “Composite back reflector for photovoltaic device” and directed to a photovoltaice device having a composite back reflector on a substrate, the reflector including an electrically conducting, texturizing layer disposed on the substrate, a light reflecting layer conformally disposed on the texturizing layer, and photovoltaic material disposed on the composite back reflector. Filed September 4, 1992; issued March 22, 1994; expired September 4, 2012.
