Liquid crystal display with switchable viewing angle and method of viewing angle control

An LCD (liquid crystal display) with a switchable viewing angle, comprising:

• a first substrate being provided with a first electrode and a first alignment film thereon;
• a second substrate being provided with a second electrode, a third electrode and a second alignment film thereon, wherein one of the second electrode and the third electrode is a common electrode, and the other one of the second electrode and the third electrode is a pixel electrode;
• and
• a liquid crystal layer being disposed between the first alignment film and the second alignment film, the liquid crystal layer comprising a plurality of liquid crystal molecules, wherein the liquid crystal molecules are negative liquid crystal molecules, all of the liquid crystal molecules in the liquid crystal layer are tilted at the same pretilt angle relative to the alignment films, the pretilt angle is in the range of 30°˜70°;
• and a printed circuit board for providing a bias voltage to the first electrode;
• wherein when no bias voltage is applied to the first electrode, the LCD is displayed with a narrow viewing angle;
• and when a bias voltage is applied to the first electrode to generate a vertical electric field between the first substrate and the second substrate, the LCD is displayed with a wide viewing angle;
• wherein when the LCD is displayed with a wide viewing angle, the bias voltage applied to the first electrode is in the range of 4V to 8V.