Display device with image shift

A display device, comprising:

• a controller to receive original image data and output a display image signal;
• and
• a display panel to receive the display image signal and display a display image corresponding to the display image signal,
• wherein:
• the controller includes:
• an image shift controller to generate shifted image data by modulating the original image data to shift the display image sequentially along a preset shift path on the display panel;
• and
• a memory to store a shift path value indicating a distance by which the display image has been shifted on the preset shift path, the shift path value to be stored in the memory when the display device is powered on and to be retained in the memory when the display device is powered off;
• and
• the image shift controller generates the display image signal by processing the shifted image data, and when the display device is powered on after being powered off, the image shift controller generates shifted image data corresponding to a shift path value for a start location on the preset shift path, and then generates shifted image data corresponding to the shift path value stored in the memory,
• wherein the image shift controller includes an image smoother configured to modulate the shifted image data by increasing or decreasing gray values of pixels such that a difference in the gray values of the pixels between successive frames does not exceed a predetermined threshold value, and
• wherein, for each pixel whose gray value in the shifted image data for a current frame differs from the corresponding pixel in the shifted image data for a previous frame by more than the predetermined threshold value, the image smoother is configured to increase or decrease the gray value of that pixel by only one gray value per frame.