Nobel Prize in Physics laureate Shuji Nakamura, who was lauded by The Royal Swedish Academy of Sciences as the Edison of 21^st Century, recently noted laser diodes would eventually replace LEDs in lighting applications within the next decade at a fair in China last month, reported China’s LED Patent Alliance (LPA).

Nakamura made the remarks during a press conference at the 2016 China (Chengdu) Global Innovation and Entrepreneurship Fair that took place on June 25, 2016.

His comments sparked heated debate in online forums that lasers lighting efficiency were 1,000 times more effective than LEDs, capable of increasing the illumination distance, which greatly improves its safety, and minimalizes light source size making it more compact.

This has made laser a super popular product, and news that laser diodes would replace LEDs in 10 years quickly spread on China’s online social media platform Weixin. Let us forget for one second, whether Nakamura’s claim that laser diodes can magically replace LED lighting within a short time frame. His assessment that “laser diodes are 1,000 times more efficient than LEDs” is definitely impossible. This is because for lasers to be 1,000 times more efficient than LEDs, the LED luminaires efficiency would have to be lower than 0.1%. In the lighting industry, there is a theoretical parameter called maximum spectrum luminous efficacy, which is represented as K_m and equates to a maximum efficiency of 683 lm/w. This is the limit of visible range of electricity converted into light. So what does this mean? For 1W of electricity to be converted into visible light, it cannot be greater than 683 lm. If laser has an efficiency 1,000 times larger than LEDs, it would indicate LEDs efficiency is lower than 0.683 lm/w.

Taking a closer look at the differences between LED lighting and laser diode powered lighting, there are few differences between LED and lasers excitation sources. The only difference is in a YAG laser, where an additional stimulated emission is included, and LEDs add a phosphor conversion process after light emission. Visually, lasers deliver excellent monochrome performance, while LEDs have a wider light spectrum that is suited for displays and lighting. However, LEDs cannot catch up with lasers in terms of brightness. This is because lasers are very strong directional light sources, they are basically linear light sources. If lasers are not processed, it will be much brighter than LEDs. Lasers visual effects as a RGB light source is still immature, and in an experimental phase.

Then there is the question of what are lasers? Does China have laser patents?

1)    What is laser?

The different types of laser lights include IR lasers and visible lasers.

IR lasers usually place semiconductor materials in the electron hole and use electron recombination process, as excited electrons drop from the stimulated energy levels, it releases photons which emits light. The photons in the resonant cavity than produce resonating photons that are than spread and formed into laser light that can be applied in night vision, surveillance cameras, and other night time cameras.

In theory, visible lasers can be white lasers based on blue lasers that are excited by electricity to emit light, and once it passes a phosphor coatings it is converted into white light. For instance, BMW’s concept car in 2011 showcased a laser headlight. Another combination would be red, green and blue lasers that are mixed to produce white light, or real color lighting (for example QingDao ZongKe SPEC-TECH’s laser lights.)

Are there any laser patents?

The answer is affirmative. German manufacturer Siemens AG started deploying its laser patent strategy as early as 1970s, and acquired patents for its “Laser Lighting System” in Germany, U.S., Netherlands, UK and other countries. Its U.S. patent is US3688281A.

Image US3688281A. (Image Courtesy of USTPO)

This is a method and device for retrieving information from a matrix of holograms arranged in columns and rows, but it was never applied in laser lighting R&D. Laser R&D has been ongoing throughout history, but has been rather unknown. There are even people that claim laser concept emerged much earlier than LED lighting, but this cannot be proven.

Let’s take a look of China’s laser lighting patent deployment.

China’s laser patent deployment started much slower, this is mainly because China’s traditional lighting industries and government policies. China’s first laser patent application was filed in 1985 by Jinhua Tian, the patent was named “Ultra-highly efficient laser light” and was given the patent number CN85102745. However, the patent review committee revoked the patent application for violating physics “the law of conservation of energy”. In 1993, Shanghai Institute of Optics and Fine Mechanics (SIOM) applied for a patent for “manufacturing a semiconductor laser lighting and system”, which has a patent number of CN1100187A.

4 CN1100187 patent.

Starting from 2006, more Chinese inventors and enterprises started to deploy their laser lighting patent strategies, even though the volume of patents remain low (see figure 5). Primary patents in the field are still G02B27/09 and G03B15/05, which are optical components, system, devices, cameras, or electronic flash equipment that are integrated with electronic flash components in laser applications. The remaining patents are mainly focused on optic recording, laser etching, telescopes and other fields. This is because there are a lot of research in the laser lighting industry, but it was only in the last few years that laser lighting patents started to increase, so manufacturers that are interested in the field can spend time evaluating whether they want to invest in the field.

Number of completed laser patent applications. (Image courtesy of LED Patent Alliance)

Type of laser patent applications. (Image courtesy of LED Patent Alliance)

Public patent application trends from 1999 to 2016. (Image courtesy of LED Patent Alliance)

In the next 10 years, whether laser lighting can replace LEDs cannot be accurately predicted. However, as laser lights becomes smaller, more compact, and has a further projection distance, it might replace LED lights in certain applications, such as automotive headlights and display technologies. However, in the general lighting sector, innovative centers and intellectual property engineers are still skeptical about LED lights replacing lasers. Yet, the industry knows for sure that innovative concepts might need to undergo developments in the next 10 years to 30 years before it becomes a big trend in the industry. Hence, these technologies are worth following.