White LED patent status
The five major companies Nichia, Osram, Toyoda Gosei, Cree, and Lumileds almost control the entire white LED industry. The patents are dense here, which can be said to be a minefield, which makes other businesses who want to enter this field worried and discouraged. Despite this, many companies Still strive to gain a foothold in this field. With the wide and rapid application of white light LEDs, as well as the heavy investment of major companies in this field, legal affairs such as patent infringement and cross-licensing continue to occur.
Since September 2005, the relationship between licensing and patent disputes (main intellectual property relations) in the white LED field
After a long period of patent disputes, the five major companies have chosen the "mutual (cross) authorization" method to settle conflicts and disputes between them (as shown above). In this way, the LED industry is quiet. But for other businesses in this field or who want to enter this field, life seems to be even more difficult.
The scope of authorization covers all aspects of fixed light-emitting transistor technology, but the most important and meaningful technology in this field is the technology that uses phosphors to convert blue and ultraviolet light into white light. In this way, major companies no longer have to argue with each other over the validity of their own various patents, but instead focus on whether anyone has infringed their patents and license their own technologies to other inferior ones. company.
What's bad is that these agreements don't help much to clarify IP locations, determine which patents are valid, and which have priority, etc. Reading the patent documents will reveal that there are a series of patent documents that duplicate or even conflict with the US patents. At present, laws and regulations concerning infringement have been gradually promulgated. Although some of the appeals have infringements, other people have rejected such appeals. So far, the real laws and regulations on the validity of patents are still very limited.
In many practical cases, the subject of patent protection is not very clear. At that time, there was not even a really effective patent protecting the light-emitting principle of white LEDs. The 1970 U.S. patent protecting the use of screens to convert colors is no exception. In 1991, Nichia applied for a patent in the U.S. that used phosphors to convert blue LEDs into white light, but was rejected in the U.S. As for the reason for the rejection, I don’t know if it is because the US Patent Office has already accepted patents of the same nature.
Comparing many patents, it is not difficult to see that their protection focuses on the use of phosphors (before the cross agreement was signed, Nichia appealed to Osram for infringement of a Japanese patent and was rejected. The reason for the rejection was that Osram did not use garnet phosphorescence. body). Therefore, subsequent patents began to expand the scope of protection, so that the content of protection became more and more extensive but at the same time it became less and less clear.
White LED U.S. Patent Status
If Nichia first commercialized white LEDs in 1996, then the history of white LEDs can be said to be very complicated. In the United States, the patent status is roughly as follows:
Bell Laboratories uses single or multiple phosphors for the luminescence of the phosphor screen, which is protected by a US patent (3,691,482) and also establishes the principle of light wavelength conversion. The patent acceptance time was January 17, 1970.
Nichia applied for a Japanese patent on November 25, 1991 for the method "phosphor is used in resin and used for molding". The technology was published on June 18, 1993, but the application was filed in June 1998. It was rejected on the 23rd and on December 2, 1999, Nichia withdrew the application.
Cree has the ownership of a patent 6,600,175 (this patent was originally granted to AMTI), the acceptance date is March 26, 1996, and the grant date is July 29, 2003. The patent claims to protect a "device that produces white light from a single LED through a down-converted phosphor", and the patent attempts to protect all related technologies and processes. However, the patent mentions only the excitation of phosphors by light sources other than white light, and does not seem to cover the excitation of yellow phosphors by ordinary blue LEDs. Nichia mentions the excitation of yellow phosphors by blue LEDs in the patent, but it does not It discusses it, nor does it discuss garnet-based phosphor technology.
Osram's patent 6,245,259 was accepted in the United States on August 29, 2000, and the grant date was June 12, 2001, but before that, on June 26, 1997, he had obtained international patent protection. Since then, there has been a patent overlap problem. The original patent described blue, green and ultraviolet LEDs and phosphors doped with cerium, terbium or thiogarnet. This is not mentioned in the previous Nichia white LED and Nichia Japanese patent applications. The focus of this technical protection seems to be on the phosphor size specification (the size should be below 5 microns).
· HP (Agilent) patent 5,847,507 was accepted on July 14, 1997, the date of authorization is December 8, 1998. The description of this patent relates to the existing Nichia products and the focus of protection is on the principle (method) of the phosphor's light emission, which covers a wide range of phosphors of various styles.
· The first Nichia patent 5,998,925 for white LED applications was granted in the United States on December 7, 1999, and its acceptance date was July 29, 1997. It was integrated into subsequent Nichia patents 6,069,440 and 6,614,179. As expected, this patent relates to garnet-based GaN LED phosphors-describing Nichia commercial white LEDs. Although Nichia's US patent disclosure involves their earlier patents, this is also a powerful irony to the statement that "the first commercial white LED supplier has the latest priority date".
· Toyoda Gosei has a patent of 6,809,347 to protect the use of europium-doped alkaline earth orthosilicate phosphors in conjunction with blue or ultraviolet LEDs. This patent has a priority date of December 28, 2000, and the date of authorization is October 26, 2004. It seems to focus on a special phosphor design with a clear outline. It does not take the same measures as other patents. The word is vague, and its protection content is clear and clear.
Phosphor
The biggest difference from many patents is that phosphors can be selected freely. The main phosphors are as follows:
Yttrium aluminum garnet (YAG) doped with cerium, this compound material is in an excited state under the irradiation of 460 nanometer light waves, and can emit a wide range of 550 nanometer light waves;
Terbium aluminum garnet (TAG) authorized by Osram to a few manufacturers;
Phosphors composed of sulfides, such as strontium thiosate doped with europium, this compound material is excited under the irradiation of 460 nanometer light waves and can emit green light with a wavelength of 550 nanometers; or Strontium sulfide with europium element can produce red light under this condition;
The use of silicate-based phosphors has been patented by Toyoda Gosei, Tridonic and Intematix;
Whether organic phosphors or dyes (powders) and fluorescent color rendering include the first and second practices, there is no clear information yet;
Nanoparticle phosphors are the most used method in other patents, but this method (process) is not mentioned in the above articles
