Patent ID: 7834843

Claim:
A display system, comprising: a writing device configured to transmit an electromagnetic wave including an image information and a power to operate a display device, the writing device including: a first antenna unit configured to transmit the electromagnetic wave, the first antenna unit being wound in a loop a plurality of times; a third antenna unit configured to receive the electromagnetic wave, and configured to produce a third signal; an equivalent load unit configured to detect a second power based on the third signal, and configured to output a fourth signal; a controlling unit configured to execute power transmission adjustment of the electromagnetic wave according to the fourth signal; and the equivalent load unit including: an equivalent load circuit configured to consume a third power based on the third signal; and a detector configured to detect the second power based on the third power, and configured to output the fourth signal, and the display device configured to receive the electromagnetic wave and to display an image related to the image information, the display device including: a second antenna unit configured to receive the electromagnetic wave transmitted from the first antenna unit by mutual induction, the second antenna unit being wound in a loop a plurality of times; and a power extraction unit configured to extract a power from the electromagnetic wave.