Murata Manufacturing Co Ltd and Nissha Printing Co Ltd collaboratively prototyped a wireless charger for mobile machines.
The power receiving unit of the charger is equipped with an incoming circuit that Murata developed for wireless charging based on the electric field coupling method. And a film (and electrodes) having an antenna function was developed by Nissha and integrated with the battery cover of a smartphone. The two companies have applied for a patent related to the case structure of and manufacturing method for the charger.
The thickness of the electrode is several micrometers, and that of the antenna film is 0.1 to 0.2mm. The case to house a mobile machine is as thin as 1.0 to 1.2mm including its protection film and resin part.
The film is flexible and can have transparency. Therefore, it is possible to add a wireless charging function to mobile machines without changing their appearances much.
With the prototyped case, 5 to 10W of electricity can be wirelessly transmitted. The power transmission efficiency of the charger was enhanced by using Nissha's technology that forms a shape and decorates the formed object at the same time and forming electrodes. The transmission efficiency of the wireless transmission part is 90% or higher.
Murata plans to exhibit and demonstrate the prototyped charger in its booth at CEATEC Japan 2011. If the charger is sold well to mobile machine makers, it will possibly be employed for products to be released in 2013.