Video display device and cooperative control method in video display device

A cooperative control method in a video display device capable of connecting an external device and a smart phone, the smart phone including a display remotely operating the external device, the method comprising:

• detecting a connection of the external device;
• generating, by using detection of the connection of the external device as a trigger, a start signal for initiating an application software on the smart phone, wherein the application software displays, on the display of the smart phone, an operation screen for accepting an operation instruction to the external device;
• transmitting the start signal to the smart phone;
• and
• transmitting the operation instruction to the external device, the operation instruction being accepted by the smart phone through the application software.

A cooperative control method in a device cooperation system comprising an external device, a video display device, and a smart phone, the smart phone accepting operation from a user, the cooperative control method comprising:

• by the video display device, detecting a connection of the external device, and transmitting, to the smart phone, a start signal which is generated by using detection of the external device as a trigger, wherein the start signal initiates an application software on the smart phone, wherein the application software displays, on a display of the smart phone, an operation screen for accepting an operation instruction to the external device;
• by the smart phone, displaying the operation screen of the application software on the display of the smart phone when receiving the start signal;
• by the smart phone, transmitting the operation instruction accepted through the operation screen to the video display device;
• by the video display device, transmitting the operation instruction obtained from the smart phone to the external device;
• and
• by the external device, transmitting video data held by the external device to the video display device according to the operation instruction.