Stereoscopic image display device and driving method for the same

A stereoscopic image display device comprising:

• a display panel configured to display an image;
• a switchable panel located on the display panel and having a plurality of switchable regions, the switchable panel being configured to convert the image into a 3D image;
• a voltage applying unit configured to apply voltage to the switchable panel in such a way as to divide each switchable region into a barrier region and a transmitting region;
• and
• a controller configured to control the voltage applying unit in such a way as to adjust a position of the barrier region and a width of the barrier region within each switchable region,
• wherein in case that the viewer has not changed position for more than a period of critical time, the ratio of the transmitting region to each switchable region is reduced.