Taiwan IP Court invalidates basic patent for white LED

Nichia’s invention patent TW156177 relates to a light-emitting diode (LED) comprising a light-emitting component and a phosphor capable of absorbing some of the light emitted, as well as producing light of a different wavelength. It is characterised by the fact that:

  • the light-emitting component is made of a nitride compound semiconductor, which has only one main peak wavelength ranging between 400 and 530nm;
  • the phosphor is made of yttrium aluminium garnet (YAG); and
  • the light produced by the light-emitting component and that produced by the phosphor are different.

This is known as the ‘YAG' patent and is one of the fundamental patents for white LEDs.

Everlight Electronics Co, Ltd filed an invalidation action at the Taiwanese Intellectual Property Office (TIPO) against Nichia’s YAG patent, citing issues relating to:

  • novelty, based on the disclosure of a brochure published in 1995; and
  • inventive step, based on the combination of prior art (including JPH 5-152609, JP 49-1221 and EP 0209942).  

The TIPO accepted the evidence (including the brochure) and found the YAG patent invalid. Nichia appealed before the Ministry of Economic Affairs (MOEA). The MOEA deemed the brochure inadmissible, but agreed that the combination of the prior art demonstrated a lack of inventive step and therefore dismissed the appeal. Nichia then appealed to Taiwan’s IP Court, which also dismissed Nichia’s appeal due to a lack of inventive step. 

The IP Court reasoned that the document provided by Everlight could not be classified as a brochure as it was only one page of a two-sided printed document and no subsequent pages were found. Further, Everlight could not prove the publication date of the brochure, as it was not signed by the writer or publisher. Therefore, the IP Court deemed the brochure inadmissible as evidence. 

On the issue of inventive step, the Taiwan Patent Act stipulates that a patent must not be granted if a person ordinarily skilled in the relevant art can easily make the invention based on prior art. However, there has been an ongoing debate regarding the method of evaluating a skilled person’s motivation to combine two or more pieces of prior art. In this case, the IP Court reasoned that the items presented as evidence were alike in respect of the technical problem to be solved, the functions and the technical effects, and those items of evidence were considered probative (as they were similar, close and relevant to each other). Further, the IP Court suggested that it was foreseeable that skilled persons could combine the phosphor made of YAG (known as yellow phosphor) with the nitride light-emitting semiconductor compound (known as the blue chip) to obtain a white LED, in response to the high market demand for such products. Therefore, the IP Court concluded that the evidence submitted by Everlight could allow a person with the relevant skills to recreate the YAG patent invention. 

The IP Court allowed Everlight to submit new evidence to strengthen its case, based primarily on Article 33 of the Intellectual Property Case Adjudication Act. A grant to submit new evidence, submitted by either the invalidating party or the participant, can also increase the efficiency of resolving disputes and avoid repeated filings for invalidation actions.

Related cases
The German Federal Patent Court invalidated European Patent 936682, which corresponds to Nichia’s Taiwan Invention Patent TW156177. However, the German Federal Supreme Court reversed the decision and held that the patent was valid. Further, the US Court of Appeals for the Federal Court invalidated Nichia’s US Patent 5,998,925, which corresponds to Nichia’s Taiwan invention patent.

In the present Taiwanese case, Nichia has appealed the IP Court decision to Taiwan’s Supreme Administrative Court.

This is an Insight article, written by a selected partner as part of IAM's co-published content. Read more on Insight

Unlock unlimited access to all IAM content