A new dithering algorithm for higher image quality of liquid crystal displays

To increase the bit-depth of a liquid crystal display (LCD) and to improve the color shift, a novel dithering algorithm is presented. The concept of a conventional dithering algorithm is shown and its limitation is discussed. The proposed dithering algorithm comprises two steps: a data expansion and a three-bit reduction over eight frames. Three-bit reduction scheme over eight frames is proposed for the first time. This work shows that the color performance of LCD panels can be controlled by how to expand RGB data. Experimental results show that the proposed method can achieve full colors, i.e. 16,777,216 colors whereas the conventional one can support only 16,194,277 colors on LCD panel with only six-bit drivers. The color shift, represented by ¿u'v', of a twisted nematic (TN) panel adopting the proposed method becomes 0.015, which satisfy the regulation (¿u'v' < 0.02) on the color grayscale linearity.