The patent profile of green LED light bulbs: Cases in the US, Japan, Taiwan and China

There is an increasing demand for LED (light-emitting diode) bulbs, and technological development has become extremely significant, especially pertaining to patents. In this article, relevant LED bulb patents from the database of the United States Patent and Trademark Office (USPTO) from 1976 to 2014 have been examined and analysed. The applied patent indicator tools include patent analysis, technology life-cycle analysis, R&D ability analysis and patent classification analysis. The analysis was completed at the national, company and technology levels. At the national level, the US has the best performance. At the company level, the Switch Bulb Company, Inc. has obtained the most number of patents. According to the technological field of US Patent Classification, green LED light bulb patents mainly focus on D26/2, 362/249.n and 313/46 - especially D26/2. American companies in general have maximum success in patenting green LED light bulbs, but the Hon Hai Group, Taiwan is the only company covering these three technology fields. We demonstrate the development trend and operation of green LED light bulbs from different aspects to show that the technology gap is an important reference for other relevant LED bulb companies that plan to develop new technologies and increase their competitiveness in the future.