Wan Hui Da has made great efforts to defend the "Actifry" patent of SEB SA against many invalidation requests. In a decision dated September 2015, the Patent Reexamination Board (PRB) qualifies the invention as a "breakthrough technology", and maintains the validity of the patent. According to publicly available records, this is the first time that the PRB specifically bases its decision on such concept of “breakthrough” in a patent invalidity proceeding.

Case Brief

In 2005, SEB SA filed in China an invention patent CN200580018875.3 for a “fryer that can automatically coat the food with oil”. The patent was granted in 2009. The patented product was named “Actifry”. It heats the food by hot air flow and at the same time uses a paddle to mix the oil with the food, in particular potato chips, and the rotation of the paddle can make the food receive the heat evenly. The patentee created a term “dry fryer” to describe the technology. Compared with prior arts, this fryer saves a lot of oil (it can fry one pot of potato chips with only one spoon of oil), and works very efficiently. The patented fryer became a great success in the world market, with accumulated sales amounting to over seven million units.

Since 2009, quite a few Chinese competitors have been trying to use this patent. When SEB SA filed lawsuits against them, they filed invalidation requests, all together six times by 2015. The PRB heard the last three invalidation requests in one hearing in March 2015. In the invalidation requests, the applicants cited 13 existing technologies, mostly from 1960s to early 1990s. Those technologies were about heating with air flow. They were also about various ways of mixing the food with oil, such as using a rotating basket with the bottom immersed in oil, spraying fine drops of oil on the food, or coating the food with oil before the heating. However, none of the cited prior arts disclosed any device that can mix the food with oil and at the same time turn the food evenly in the heating process. The petitioners of invalidation also alleged that using a paddle to mix the food with oil was an obvious solution (common knowledge).

In the response, SEB SA argued that “dry frying” is a revolutionary technical solution compared with prior arts. The technical effect was not achieved by simply combining the current prior arts as alleged by the petitioners. SEB SA argued that, in evaluating the inventiveness of the patent, one should not look for prior arts relating to each technical feature mechanically, but should fully comprehend the prior technologies and the patent’s technical solution/contribution to the prior arts as a whole. In the subject case, the “dry frying” technology was a breakthrough in comparison with prior cooking methods. The direct hot air flow impact on the food could quickly dry outer layer of the food, while the mixing device could coat the food with a thin layer of oil and turn the food for constant and even heating. It achieved the effect of traditional immersing frying, but saving a great deal of oil and causing little pollution. It solved a long time problem in the industry. The popularity of the patented products and the numerous infringements of this technology proved the value and inventiveness of this patent.

In September 2015, the PRB held that the subject patent was a "breakthrough technology" in comparison with prior arts, and maintained the validity of the patent.

WAN HUI DA represented the patentee in these proceedings.


Article 22 of China’s Patent Law defines “inventiveness” as that, compared with existing technologies, the invention shall have “prominent and substantial features” and constitute a “remarkable advancement”. Section 1 of Chapter 4, Part Two of the Patent Examination Guideline categorizes six kinds of patents. The first one is the breakthrough patent, which refers to a brand new technical solution that has no precedent in technical history and opens a new era in technology development. This kind of patent has the highest inventiveness. The Guideline lists some examples such as radar, laser, radio, and so on.

In this invalidation case, SEB SA argued on the method for evaluating the inventiveness, the long felt need and the commercial success, and convinced the PRB that the patent is a breakthrough technology. Such recognition no doubt enhances the protection of the patent in its enforcement proceedings.