Patent ID: 7978465

Claim:
A display device unit, comprising a display device that is provided with a first internal circuit and configured to operate by itself, and a plurality of function expanding modules, each of which comprises a second internal circuit for outputting a function expanding signal required for expanding an input operation function with respect to said display device by a user, and an operation key for the user to input operations, wherein: said display device and said plurality of function expanding modules respectively comprise an expanding connector for electrically connecting said respective first and second internal circuits by being mechanically connected to each other, under a state where each of said function expanding modules is stacked at a rear part of said display device, said display device is configured to operate by itself without said modules being stacked, said input operation function of said display device is configured to be expanded by outputting said function expanding signal to said display device from said function expanding modules when said display device and respective internal circuits of each of said function expanding modules are connected through both of said expanding connectors under a state where said modules are loaded by being stacked, and the operation key is electrically connected to the second internal circuit and the second internal circuit is configured to output the function expanding signal to the display device for operating the display device according to the input by the user to the operation key.