I previously wrote about the patents for saleÂ as a resultÂ of the bankruptcy of Massachusetts PV company Evergreen Solar.
ThoseÂ patents include U.S. Patents Nos. 6,814,802, 7,022,180Â and 7,507,291, each entitled “Method and apparatus for growing multiple crystalline ribbons from a single crucible” (collectively “Ribbon Patents”).
The Ribbon Patents cover Evergreen’s core innovation, a PV manufacturing process known as String Ribbon technology.
In a fascinating development, the U.S. Department of Energy (DOE) wrote a letter to Evergreen demanding that it assign title to the Ribbon Patents to DOE (DOE_Letter):
The Department of Energy (“DOE”) hereby demands that Evergreen Solar Inc. assign title to DOE for the following invention: method and apparatus for growing multiple crystalline ribbons from a single crucible (“the Gemini Method”), including U.S. Patent Nos. 6,814,802; 7,022,180; and 7,507,291 and all other pending U.S. or foreign patent applications and patents that relate or claim priority to any of the foregoing U.S. patents.
The DOE concurrently filed a motion in the Evergreen bankruptcy proceeding to get the court’s permission toÂ obtain title to the Ribbon PatentsÂ (DOE_Motion).
According to the DOE letter and motion papers, the research and development that led to the String Ribbon technology was fundedÂ at least in part byÂ DOE.Â The letter states:
We believe the Gemini Method is a “subject invention” as defined by the Bayh-Dole Act and NREL subcontract ZDO-2-30628 . . . to which Evergreen Solar Inc. was a party.
The motion states that the federally funded research led to the String Ribbon process:
Under the Funding Agreement, Evergreen conducted the Gemini project to develop a method to generate two String Ribbons of silicon simultaneously out of [a] single crucible of molten silicon rather than just one String Ribbon at a time.
Under the Bayh-Dole Act, which governs rights in government-funded technology (see my post on Bayh-DoleÂ here), EvergreenÂ had to disclose to DOE any inventions developed with the federal funding and provide notice to DOE that it elected to retain title to the inventions.Â
According to DOE, EvergreenÂ failed to do so for the String Ribbon technology, so DOE can take ownerhsip of the Ribbon Patents.
The invention of the Ribbon PatentsÂ enables continuous and concurrent growth of multiple semiconductor ribbons from a single crucible.
Figure 2A, for example, shows a continuous two-ribbon dual growth system (20) including a crucible (21) having a melt (22) of silicon and two pairs of strings (25a, 25b) extending through the crucible.Â
Each of the pairs of string (25a, 25b) has a fixed distance between the strings.Â Two crystalline ribbons (27a, 27b)Â of silicon are drawn from the melt (22) as the cooler liquid silicon crystallizes at the tops of the menisci (29a, 29b).Â
The pairs of strings (25a, 25b) pass through holes in the bottom of the crucible and become incorporated in and define the edge boundaries of the crystalline ribbons (27a, 27b).
According to the Ribbon Patents, the disclosed methods and apparatus allow for a substantially better rate of production and efficiency and reduce capital, material, and labor costs.Â
According to some news reports, Chinese solar manufacturers have shown considerable interest in the auction of Evergreen’s assets.Â Apparently, DOE wants to block sale of the String Ribbon technology to foreign companies.
Indeed, DOE’s motion papers argue the court should allow it to maintain its rights in the Ribbon PatentsÂ to “preventÂ foreign entities from gaining control over federally-funded technology and competing with American industry unfairly.”