Cree Inc. of Durham, N.C., and Seoul Semiconductor Co. Ltd. in South Korea have signed two agreements that will increase cooperation. According to a five-year supply contract, Seoul Semiconductor will purchase at least $40 million of Cree’s LED products during the first five quarters of the arrangement. Purchasing commitments for the remainder of the contract will be negotiated annually. The situation will continue until June 2011, at which point it may be extended.In addition, the companies have cross-licensed certain patent rights relating to white LED technologies and have agreed to cooperate in defending these rights.