A mobile terminal comprising: a wireless communication unit to provide wireless communication; a touch screen; and a controller to: deactivate the display screen, receive a first touch on the deactivated display screen, receive a second touch on the deactivated display screen while the first touch is maintained on the deactivated display screen, generate a first image based on the second touch, execute a memo function on the mobile terminal in which the second touch corresponds to input memo information, and maintain the execution of the memo function while the first touch is maintained on the deactivated display screen, wherein the controller further comprises means to: receive a new second touch on the deactivated display screen after a reference time elapses while the first touch input is being continuously maintained, generate a second image based on the new second touch, in response to the first touch being released: activate the deactivated display screen, and when a region where the new second touch is applied overlaps with a region where the second touch is applied, output the first image and the second image to different regions so that the first image and the second image are not output in an overlapped wherein the memo information includes an image corresponding to a trajectory of the second touch. a wireless communication unit to provide wireless communication; a touch screen; and a controller to: deactivate the display screen, receive a first touch on the deactivated display screen, receive a second touch on the deactivated display screen while the first touch is maintained on the deactivated display screen, generate a first image based on the second touch, execute a memo function on the mobile terminal in which the second touch corresponds to input memo information, and maintain the execution of the memo function while the first touch is maintained on the deactivated display screen, deactivate the display screen, receive a first touch on the deactivated display screen, receive a second touch on the deactivated display screen while the first touch is maintained on the deactivated display screen, generate a first image based on the second touch, execute a memo function on the mobile terminal in which the second touch corresponds to input memo information, and maintain the execution of the memo function while the first touch is maintained on the deactivated display screen, wherein the controller further comprises means to: receive a new second touch on the deactivated display screen after a reference time elapses while the first touch input is being continuously maintained, generate a second image based on the new second touch, in response to the first touch being released: activate the deactivated display screen, and when a region where the new second touch is applied overlaps with a region where the second touch is applied, output the first image and the second image to different regions so that the first image and the second image are not output in an overlapped wherein the memo information includes an image corresponding to a trajectory of the second touch. receive a new second touch on the deactivated display screen after a reference time elapses while the first touch input is being continuously maintained, generate a second image based on the new second touch, in response to the first touch being released: activate the deactivated display screen, and when a region where the new second touch is applied overlaps with a region where the second touch is applied, output the first image and the second image to different regions so that the first image and the second image are not output in an overlapped wherein the memo information includes an image corresponding to a trajectory of the second touch. activate the deactivated display screen, and when a region where the new second touch is applied overlaps with a region where the second touch is applied, output the first image and the second image to different regions so that the first image and the second image are not output in an overlapped wherein the memo information includes an image corresponding to a trajectory of the second touch.