The lateral field existing in the ON state of a liquid crystal display (LCD) can result in an undesired reverse tilt domain in each pixel, thereby leading to poor contrast ratio of the display. As pixel size becomes smaller to meet the requirements of a high-information-content display, the problem becomes worse. In this paper, we present experimental results and theoretical analysis of the lateral field effect in the twisted nematic (TN) cell, which is most commonly used in the thin-film-transistor liquid crystal displays (TFT/LCD). The effects of various cell parameters, such as pretilt angle, bus-line-to-pixel spacing, and cell gap thickness, on the pixel reverse tilt domain and on the corresponding optical performance have been studied in detail. The results are useful for TFT/LCD design and cell fabrication.