Mitsubishi Chemical Corporation (MCC; Head office: Chiyoda-ku, Tokyo, President: Hiroaki Ishizuka), National Institute for Materials Science (NIMS; Location: Tsukuba-shi, Ibaraki Prefecture; President: Sukekatsu Ushioda), Nichia Corporation (Nichia; Head office: Anan-shi, Tokushima; President: Eiji Ogawa), and Citizen Electronics Co., Ltd. (Citizen; Head office: Fujiyoshida-shi, Yamanashi Prefecture; President: Yoshihiro Goda) have announced that MCC and Nichia have concluded a cross-licensing agreement for patents of nitride-type red phosphor (Note 1), which is widely used in white light-emitting diodes (LEDs).
The conventional white LED using a yellow phosphor has been available over the years, but its white light had less of a reddish component than natural light. The nitride-type red phosphor, called CASN or SCASN phosphor (or 1113 phosphor), adds this reddish component, which could not otherwise be achieved, to white LEDs. This creates a white light that is closer to natural light. The white LEDs containing this red phosphor are also used in various lighting applications and in backlighting for LCD panels.
In 2010, MCC and Nichia reached a basic agreement on cross-licensing of the red phosphor patents each company owns. Since then, both companies continued detailed discussions with NIMS, and all parties have now reached an accord on the final content of the agreement.
The patents targeted by the cross-licensing in the agreement include Nichias patents and MCC and NIMSs patents, as described at the end (Note 2). In addition, the companies announced that MCC, NIMS, Nichia, and Citizen have reached an agreement to share the U.S. patent (No. 8409470), which is one of the basic patents that MCC and NIMS currently co-own.
The companies expect the conclusion of the cross-licensing agreement and shared U.S. patent to further stabilize their patent rights related to the red phosphor, and enhance the business base of MCC and Nichia.
MCC, NIMS, Nichia, and Citizen will continue their initiatives to expand the white LED market using the red phosphor.
A phosphor with a basic composition of (Sr, Ca) AlSiN3: Eu, etc. It is a red phosphor, which is most broadly used for white LEDs thanks to its high brightness and reliability. This phosphor is generally called CASN or SCASN phosphor, or 1113 phosphor.
A typical example of patents targeted by the cross-licensing agreement
• Patents owned by MCC, NIMS
JP3837588, US8409470, KR10-0816693, CNZL200480040967.7, TWI317755, JP4234161, JP4070219, US8148887, KR10-1204413, CNZL200580005112.5, TWI-278128, etc.
• Patents owned by Nichia
JP4414821, JP4415065, JP4422653, JP4511849, JP4511885, US7273568, US7432647, US7476337, US7476338, EP1568753, EP1630219, etc.
*These patents are co-owned by Nichia and Dowa Electronics Materials Co., Ltd. at the present time, but the ownership will be changed to Nichia and Citizen after conclusion of this cross-licensing agreement.
Mitsubishi Chemical Holdings Corporation
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