A display device comprising: a display; a first sensor configured to sense movement; a second sensor configured to sense illuminance; and a processor operatively connected with the display, the first sensor, and the second sensor, an input interface configured to receive a user input, wherein the processor is configured to: operate in one of a first mode and a second mode, the first mode being a mode in which a dynamic image is displayed in the display, and the second mode being a mode in which a static image is displayed in the display or the display is turned off depending on whether a movement of a user is sensed by the first sensor, wherein the first sensor is an image sensor, in response to a first user input received through the input interface in the first mode, operate in the second mode; and in response to a second user input received through the input interface in the first mode, turn off the display, the first sensor, and the second sensor, set a first critical time period after a transition to the second mode from the first mode, for sensing the movement, the first critical time period being set based on the illuminance, such that in response to a lower illuminance the first critical time period is increased, and in response to a higher illuminance the first critical time period is decreased, and in response to a movement of a user being sensed by the first sensor, in the second mode within the first critical time period, control the display to display the static image. a display; a first sensor configured to sense movement; a second sensor configured to sense illuminance; and a processor operatively connected with the display, the first sensor, and the second sensor, an input interface configured to receive a user input, wherein the processor is configured to: operate in one of a first mode and a second mode, the first mode being a mode in which a dynamic image is displayed in the display, and the second mode being a mode in which a static image is displayed in the display or the display is turned off depending on whether a movement of a user is sensed by the first sensor, wherein the first sensor is an image sensor, in response to a first user input received through the input interface in the first mode, operate in the second mode; and in response to a second user input received through the input interface in the first mode, turn off the display, the first sensor, and the second sensor, set a first critical time period after a transition to the second mode from the first mode, for sensing the movement, the first critical time period being set based on the illuminance, such that in response to a lower illuminance the first critical time period is increased, and in response to a higher illuminance the first critical time period is decreased, and in response to a movement of a user being sensed by the first sensor, in the second mode within the first critical time period, control the display to display the static image. set a first critical time period after a transition to the second mode from the first mode, for sensing the movement, the first critical time period being set based on the illuminance, such that in response to a lower illuminance the first critical time period is increased, and in response to a higher illuminance the first critical time period is decreased, and in response to a movement of a user being sensed by the first sensor, in the second mode within the first critical time period, control the display to display the static image.