Wireless power supply patent Japan dominates in smart phones and cars

The contactless power supply technology, that is, the wireless power supply technology, as the name suggests, is a technology that does not require a plug to be in contact with the socket and that does not require a wire (wireless) to transmit power. The principle has long been known and has been applied to various commodities.

As early as the end of the 20th century, many products used non-contact power supply technology, and research aimed at increasing capacity has been ongoing. In 2007, the Massachusetts Institute of Technology (MIT) research team successfully used magnetic resonance to achieve high-power, high-efficiency contactless power with a maximum transmission distance of several meters. As soon as the news came out, the society’s attention to non-contact power supply surged, and research and development also became active.

In the "2014 Patent Application Technology Trend Survey", the Japan Patent Office investigated the patent application trends of non-contact power supply related technologies and identified some cases (summary of the investigation report in PDF format). Here's a look at the main content of the survey.

Figure 1 is a technical overview of the survey. In order to summarize the patent documents, the survey is divided into "technical problems" such as "power supply method" such as magnetic field coupling method and electric field coupling method, "application technology" such as vehicles and mobile products, failure measures, and countermeasures against small foreign object invasion. , "sub-structure technology" and "control technology" several major categories, and then subdivided the technical categories.



Figure 1: Technical Overview (click to enlarge)

The number of patent applications according to the nationality of the applicant: the number reflects the impact of MIT

The number of patent applications related to contactless power supply technology was 799 in 2006, which has soared since 2007 and has increased to 3,905 in 2011 (about 5 times in 2006). As mentioned earlier, this may be the impact of MIT's 2007 research report on magnetic contactless contactless power supply. After the results of the MIT release, the number of applications from Japanese and US companies began to increase, and the number of applications from European and Korean companies followed closely (Figure 2).




Figure 2: Number of applications and the number of applications according to the applicant's nationality (applicable: Japan, the United States, Europe, China and South Korea, application year (priority claim year): 2000-2012)
Note: All data may not be covered after 2011 due to delays in database entry, time differences between PCT applications being transferred to countries, etc.
According to the applicant's nationality statistics, Japan has technical advantages in the field of smart phones and automobiles.

The main uses for contactless power supply are mobile products such as smartphones and vehicles such as pure electric vehicles (EVs). Let's look at the number of patent applications for which these applications are based on the applicant's statistics.

The number of applications for contactless power supply for mobile products such as smartphones is 114 pieces (Second) of Seiko Epson, 93 (3rd) by Sony, 82 (4th) by Panasonic, and 104 (2nd) by Samsung Electronics. LG Electronics has 63 (5th), and Japanese and Korean home appliance manufacturers have a large number of applications (Table 1). Seiko Epson applied for a large number of patents between 2007 and 2009, but has since decreased.


Table 1: Top 10 applications for technology categories (mobile phones and smartphones) by applicants (applicable areas: Japan, USA, Europe, China and Korea, application year (priority claim year): 1995-2012)


On the other hand, the number of applications for contactless power supply for vehicles such as EVs is 503 Toyota (1st), Nissan 124 (4th), Toyota Automatic Weaving Machine 175 (2nd), Sumitomo Denso 115 (5th place), Japanese automakers and auto parts manufacturers have a large number of applications (Table 2).


Table 2: Top 10 technical applications (EV/PHEV) according to the applicant's statistics (applicable places: Japan, the United States, Europe, China and South Korea, application year (priority claim year): 1995-2012)



Patents that use weak electric waves in the air continue to increase

In addition to mobile products and vehicles, the number of patent applications in other fields has also increased. That is to use the weak electric waves in the air to supply power.

In recent years, there have been more and more sensors installed in an environment in which humans are difficult to access and in an environment with heavy maintenance burden, and it is very difficult to replace the batteries. If you can convert the energy around the sensor into electrical energy and store it, you don't need to replace the battery. This kind of technology is called energy harvesting, and it is expected to create a huge market after being fully put into practical use. Related to this technology, the number of patent applications for generating electricity using weak electric waves in space is 70 (41%) for US companies and 26 (15%) for Japanese companies. Although the number is small, it is slowly increasing (Figure 3). .




Figure 3: Technology category (medium class: using weak air waves in the air) The number of applications and the number of applications according to the nationality of the applicant (applicable: Japan, the United States, Europe, China and South Korea, the application year (priority claim) Year) 2000~2012)
Note: All data may not be covered after 2011 due to delays in database entry, time differences between PCT applications being transferred to countries, etc.
According to the statistics of the subject, Japanese companies are proud

There are three important issues in the non-contact power supply technology, namely, "measures between foreign bodies entering and receiving power receiving units", "measures against leakage of electromagnetic fields", and "measures for dislocation of power transmission and reception units". In these respects, Japanese companies have applied for a large number of patents (Figures 4-6).




Figure 4: Technical categories (medium: foreign body intrusion countermeasures) The number of applications and the number of applications according to the nationality of the applicant (applicable: Japan, the United States, Europe, China and South Korea, the application year (priority claim year) 2000- 2012)
Note: All data may not be covered after 2011 due to delays in database entry, time differences between PCT applications being transferred to countries, etc.


Figure 5: Technical categories (medium category: leakage electromagnetic field countermeasures) The number of applications and the number of applications according to the nationality of the applicant (applicable: Japan, the United States, Europe, China and South Korea, the application year (priority claim year) 2000 ~ 2012)
Note: All data may not be covered after 2011 due to delays in database entry, time differences between PCT applications being transferred to countries, etc.


Figure 6: Technical categories (medium class: Dispatch for power transmission and reception) The number of applications and the number of applications according to the applicant's nationality (applicable: Japan, the United States, Europe, China and South Korea, the application year (priority claim year) 2000 to 2012)
Note: All data may not be covered after 2011 due to delays in database entry, time differences between PCT applications being transferred to countries, etc.
Japanese companies are also outstanding in terms of local construction of mobile products.

Not only the technology for solving the problem of non-contact power supply, Japanese companies have applied for many patents in the local construction of mobile products. Many of them are technologies such as "improved coils or cores" and "improving the arrangement of multiple components" (Fig. 7).



Figure 7: Number of applications for mobile products (medium class: power-receiving equipment) according to applicant's nationality - sub-structure technology statistics (application year (priority claim year): 1995-2012) (click to enlarge)
Microwave patent, half of Japanese applicants

The microwave method is a power supply method for contactless power supply. Among the technologies related to microwave-based contactless power supply, Japanese applicants have the largest number of applications (Fig. 8).




Figure 8: Technical category (major category: microwave method) The number of applications and the number of applications according to the nationality of the applicant (applicable: Japan, the United States, Europe, China and South Korea, the application year (priority claim year) 2000 to 2012 year)
Note: All data may not be covered after 2011 due to delays in database entry, time differences between PCT applications being transferred to countries, etc.
Japanese companies should aim at the direction and exert their own advantages.

For the non-contact power supply technology for mobile products, Japanese home appliance manufacturers have applied for a number of patents, and it is important to continue to maintain a leading edge in the future. There is a strong demand for small and lightweight mobile products, and the use of contactless power supply technology requires compact installation of multiple components that make up the wireless power receiving unit, such as coils, cores, shields, and control circuits.

The Japanese company's technology has advantages in improving the coils and cores of mobile products and improving the configuration of multiple components. However, component chips are easily copied and need to be guarded against technical outflows. In order to ensure the benefits of non-contact power supply technology for mobile products, Japanese companies should promote the modularization of the power-receiving department to prevent imitation. On the other hand, it must implement an intellectual property strategy that uses patent and technical experience according to local conditions. Measures.

Japanese automakers are actively developing contactless power supplies for vehicles such as EVs. There are many opportunities for the vehicle to be charged outdoors in the parking lot. In order to ensure convenience and safety, countermeasures against foreign matter such as rain, mud, and metal sheets between the vehicle and the power supply equipment, countermeasures against leakage of electromagnetic fields, and dislocation of the power supply equipment and the parking position should be dealt with. Countermeasures and so on are particularly important. Japanese companies have also applied for many patents to solve these problems, and they have technical advantages. In the future, we should give full play to the advantages and further promote the development of technologies related to non-contact power supply for vehicles.

In the field of radio wave-based energy harvesting, microwave-based contactless power supply technology is a popular candidate. For this technology, Japanese applications have the most patents, and it can be speculated that Japan has potential technical strength in radio wave-based energy harvesting. In order to apply strong technical strength to energy harvesting based on radio waves, Japanese companies should strive to promote research and development.