By Martinne Geller and Ben Hirschler

LONDON (Reuters) - Electronic cigarette makers are racing to design and buy variations of a technology that has lit a billion-dollar boom, created a new vocabulary, and prompted a backlash from health officials worried about the impact of the new smokeless devices.

Research by Thomson Reuters shows that China - with over 300 million smokers - is the front runner in the manufacture and development of so-called e-cigarette technology, while new versions being patented include a "pay as you go" computer-assisted device and others that can deliver caffeine instead.

In 2005 just eight e-cigarette inventions were described in published patents. By 2012 the figure had jumped to 220 and by last year there were over 500 inventions, according to an analysis by the IP & Science business of Thomson Reuters. So far this year the total has reached 650. (A single invention may be covered by several patents.)

The original technology, involving battery-powered heating systems that vaporize nicotine-laced liquid, is credited to Hon Lik, a Chinese medical researcher with a 20-a-day habit, in 2003.

His invention has since become so popular that the market is now estimated to be worth $3.5 billion. Both big tobacco firms and small entrepreneurs are falling over themselves to find new ways to "vape" - a verb suddenly so mainstream the Oxford English Dictionary named it 2014's Word of the Year.

Imperial Tobacco last year snapped up the patents owned by the company Hon co-founded in a deal worth $75 million, and is suing rivals for a range of alleged patent infringements.

Part of the rush to create new devices can be explained by the prospect of stiffer regulation on existing ones after the World Health Organization said it wanted to see this, along with bans on indoor use, advertising and sales to minors.

While proponents see e-cigarettes as important tools for harm reduction, critics fear the devices may instead fuel a new wave of nicotine addiction and cite a lack of long-term scientific evidence to support their safety.



Of more than 2,000 e-cigarette inventions tracked by Thomson Reuters, 64 percent originate in China, where over half of men smoke. In second place is the United States, with 14 percent, followed by South Korea with 9 percent.

Some patented suggestions target smokers looking to regulate their nicotine intake and their spending. While offerings already on the market include thousands of e-liquid flavors from menthol to marshmallow, and even a smartphone app to show how much you are using, new patents go a step further.

Tobacco giant Philip Morris International describes an e-cigarette that would allow users to "pay as you go" by buying a certain number of doses via computer application connected to their e-cigarette. Customers could also program the device to shut off after a certain number of puffs per use to help limit intake.

Other smaller players aim to deliver doses of caffeine and other additives instead of nicotine.

A unit of mCig Inc sells VitaCigs containing vitamins and supplements such as valerian and collagen, while a company called Energy Shisha sells a caffeinated vaping stick. Patents filed by others, including Fuma International, mention tetrahydrocannabinol (THC), the active chemical in cannabis.

In general, e-cigarette patents relate to systems for heating and vaporizing liquids, as well as for charging the electronic systems, whether in a "cigalike" device or a larger "tank" system, which doesn't resemble a cigarette but gives a better "vaping" experience.

China's domination of the market reflects not only its huge number of smokers but also a wider drive by the Chinese government to forge a knowledge economy. By maximizing patents it hopes to replace the ubiquitous "Made in China" label by "Designed in China."

Since 2011, China has been the world's top patent filer for all inventions, according to the World Intellectual Property Office. Its scientists and companies now lay claim to intellectual property rights on everything from telecoms to medicine.

"Patenting globally is rising significantly year on year, driven by Chinese patenting generally," said Bob Stembridge, senior patent analyst at Thomson Reuters IP & Science.

"But I would say the e-cigarette field is growing faster than the general trend, and the bias toward China is greater than in global patenting."


(Editing by Sophie Walker)