Backlight unit and 2D/3D switchable image display device employing the backlight unit

A 2D/3D switchable image display device comprising:

• an image panel;
• a backlight unit arranged at the rear side of the image panel, the backlight unit comprising:
• a plurality of segment light sources for a left eye vision range which emit a light for a left eye vision range, and a corresponding plurality of optical sheets for the left eye vision range;
• and
• a plurality of segment light sources for a right eye vision range emitting a light for a right eye vision range, and a corresponding plurality of optical sheets for the right eye vision range;
• and
• light shield film which is arranged between each of the plurality of optical sheets for the left eye vision range and a respective one of the plurality of optical sheets for the right eye vision range, such that light passing through the plurality of optical sheets for the left eye vision range is prevented from mixing with light passing through the plurality of optical sheets for the right eye vision range,
• wherein the segment light sources for the left eye vision range and the segment light sources for the right eye vision range are alternately arranged to form a surface light source;
• and
• a lenticular lens sheet arranged between the image panel and the backlight unit,
• wherein the lenticular lens sheet comprises a plurality of semi-cylindrical lenses which extend lengthwise in a vertical direction, and
• the light for the left eye vision range and the light for the right eye vision range proceed toward the left eye vision range and the right eye vision range, respectively, and
• wherein in a 3D mode, the image panel alternately displays an image for the left eye vision range and an image for the right eye vision range, the segment light sources for the left eye vision range are driven in synchronism with the image for the left eye vision range, and the segment light sources for the right eye vision range are driven in synchronism with the image for the right eye vision range, and
• wherein in a 2D mode, the image panel displays a 2D image, and the segment light sources for the left eye vision range and the segment light sources for the right eye vision range are driven in synchronism with the 2D image.