Display apparatus and control method thereof

A display system comprising:

• a display apparatus comprising:
• a wireless power receiver configured to wirelessly receive power from an external power source;
• a display comprising a display panel configured to display an image based on a received image signal, and a backlight configured to emit light toward the display panel;
• a first communication circuitry configured to communicate with the external power source;
• a sensor configured to detect a distance between the display apparatus and a user;
• and
• a first controller configured to:
• control the backlight to emit the light based on the received power, and
• transmit information on the detected distance to the external power source if it is determined that the user is within a predetermined critical distance from the display apparatus, and
• the external power source comprising:
• a wireless power transmitter configured to wirelessly transmit the power to the display apparatus,
• a second communication circuitry configured to communicate with the display apparatus, and
• a second controller configured to, in response to receiving the information on the detected distance from the display apparatus, adjust a level of the power to correspond to the detected distance, and control the wireless power transmitter to transmit the power having the adjusted level to the display apparatus,
• wherein the first controller is further configured to control the backlight to emit the light based on the received power having the adjusted level for reducing power consumption.