Patent ID: 7804495

Claim:
A user interface system for controlling an electronic device in any of a plurality of pieces of predetermined control content on the basis of an input operation of the user, comprising: an operating device having an operation screen for accepting an input operation of the user by a touch; a position detecting device which detects a user touch position in the operation screen; a position change detecting device which detects a change in the touch position in the case where the user changes the touch position while maintaining the touch state with the operating device; and a control device which determines the control content on the basis of the touch position in the operation screen and, when the touch position changes, controls the electronic device with the control content on the basis of a control amount according to an amount of the change in the touch position, wherein in the case where the control amount is a function of the present value of the control content, the control device changes the control amount according to the change amount in such a way that a shape of graph indicative of the function becomes to a smoothly-staircase-like, and monotonously increased shape in the case where the present value is indicated by a horizontal axis, and the control amount is indicated by a vertical axis.