Preliminary analysis of domestic patents related to photonic crystal light-emitting diodes (LED)

[Source: "High-tech LED - Technology and Applications" June issue]

The existing high-power LEDs generally have the problem that the light extraction efficiency is not high enough, so the application range thereof is limited. How to further improve the light extraction efficiency of LED chips and devices has been one of the hot spots in technology research and development in this field. At present, the ways to improve the efficiency of light extraction mainly include surface roughening, pattern substrate, metal reflection, photonic crystal, vertical and flip chip, and the like. Among them, photonic crystal technology was first proposed by E. Yablonovitch and others in the late 1980s, and was quickly applied to light-emitting diodes to form photonic crystal LEDs (PC-LEDs). In view of PC-LED's unparalleled superiority of traditional LEDs, researchers at home and abroad have conducted active research and achieved considerable results, which has made the technology topic a relatively densely distributed patent in the LED field. One of the areas.

The author would like to make a rough statistics on domestic PC-LED related patents, and will make a preliminary analysis of relevant statistical results in this paper, in order to help domestic LED lighting and display related practitioners, as follows:

Referring to Figure 1, as of May 2012, a total of 119 patent applications related to LED photonic crystal technology were retrieved from the patent database published by the State Intellectual Property Office of China, including 109 invention patent applications and 10 utility model patent applications. Moreover, referring to FIG. 2, by analyzing the legal status of the 109 invention patent applications, it can be seen that only 12% of the patent applications rejected and dismissed are rejected, and another 3% of the patent applications are terminated after authorization. . Therefore, the number of patent applications related to this technical topic is small, but the quality is high, which can explain to some extent that the research related to the technical topic is still at a preliminary stage of development. Moreover, from 2001 to 2011, the number of patent applications related to the technology topic in each year has generally shown a continuous growth trend (see Figure 3), and the number of patent applicants has also increased in each year, which is further It shows that the technical theme is still in the new technology category.

Figure 1 Number and type of domestic PC-LED patents

Figure 2 Analysis of the legal status of domestic PC-LED invention patents

Figure 3 Domestic PC-LED patent annual application trend

For more information, please refer to the June issue of "High-tech LED-Technology and Applications" magazine.