Electrowetting display apparatus having low power consumption and method of driving the same

An electrowetting display apparatus comprising:

• an electrowetting pixel configured to display an image, the electrowetting pixel including a polar liquid and a nonpolar liquid arranged between a common electrode and a pixel electrode;
• and
• a driving circuit including a memory circuit configured to store an image to be displayed by the electrowetting pixel, a transistor including a gate connected to a reset line, a source connected to the pixel electrode and a drain connected to the common electrode such that the same voltage is temporarily applied to the pixel electrode and the common electrode when the transistor is on, the driving circuit configured to,
• control operations of the electrowetting pixel,
• periodically reset the electrowetting pixel during a frame period by temporarily applying the same voltage to the pixel electrode and the common electrode while the electrowetting pixel is displaying an image of a frame and not to reset the electrowetting pixel between frames, and
• provide an image stored in the memory circuit to the electrowetting pixel after the electrowetting pixel cell resets, wherein
• the electrowetting pixel includes,
• a rear substrate and a front substrate disposed facing each other,
• the pixel electrode disposed on a top surface of the rear substrate,
• a hydrophobic insulating film disposed on the pixel electrode,
• the nonpolar liquid disposed on the hydrophobic insulating film,
• the common electrode disposed on a lower surface of the front substrate, and
• the polar liquid filling a vacant space between the front substrate and the rear substrate.

A method of driving an electrowetting display apparatus, the electrowetting device including an electrowetting pixel, the electrowetting pixel including a polar liquid and a nonpolar liquid arranged between a common electrode and a pixel electrode, the method comprising:

• displaying an image by applying a fixed voltage to the common electrode of the electrowetting pixel and applying a variable voltage to the pixel electrode of the electrowetting pixel according to an image signal;
• storing the image signal in a memory circuit included in a driving circuit of the electrowetting pixel;
• periodically resetting, by the driving circuit, the electrowetting pixel during a frame period by temporarily applying the same voltage to the pixel electrode and the common electrode while the electrowetting pixel is displaying an image of a frame;
• and
• providing the image signal stored in the memory circuit to the electrowetting pixel after the electrowetting pixel resets, wherein
• the electrowetting pixel is not reset between frames, and
• the driving circuit includes,
• a first transistor including a drain connected to a data line and a gate connected to a gate line;
• a second transistor including a gate connected to a source of the first transistor and a source connected to the pixel electrode of the electrowetting pixel;
• a capacitor having a first end and a second end, the first end connected to the first transistor and the second transistor and the second end connected to ground;
• a third transistor including a gate connected to a reset line, a source connected to the pixel electrode and a drain connected to the common electrode;
• and
• a fourth transistor including a source connected to a drain of the second transistor such that the fourth transistor is connected to the second transistor in series.