1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a transflective type LCD device.
2. Discussion of the Related Art
Demands for various display devices have increased with development of information society. Accordingly, many efforts have been made to research and develop various flat display devices, such as liquid crystal display (LCD), plasma display panel (PDP), electroluminescent display (ELD), and vacuum fluorescent display (VFD). Some species of flat display devices have already been used as displays in various types of equipment.
Among the various flat display devices, liquid crystal display (LCD) devices have been most widely used due to the advantageous characteristics of thin profile, light weight, and low power consumption. Typically, a LCD device is provided as a substitute for a Cathode Ray Tube (CRT). In addition to mobile type LCD devices, such as a display for a notebook computer, LCD devices have been developed for computer monitors and televisions to receive and display broadcasting signals.
Despite various technical developments in the LCD technology for applications in different fields, research in enhancing the picture quality of the LCD device has been, in some respects, lacking as compared to other features and advantages of the LCD device. In order to use the LCD devices in various fields as a general display, LCD devices should have a high quality picture, such as high resolution and high luminance with a large-sized screen, while still maintaining a light weight, thin profile, and low power consumption.
Generally, the LCD device includes an LCD panel for displaying an image and a driver for supplying driving signals to the LCD panel. In addition, the LCD panel includes first and second substrates bonded to each other. A liquid crystal layer is formed in a cell gap between the first and second substrates. The first substrate (often referred to as a TFT array substrate) includes a plurality of gate lines arranged along a first direction at fixed intervals, a plurality of data lines arranged along a second direction perpendicular to the first direction at fixed intervals, a plurality of pixel electrodes arranged in a matrix-type configuration within pixel regions defined by crossings of the gate and data lines, and a plurality of thin film transistors enabled according to signals supplied to the gate lines for transmitting signals from the data lines to the pixel electrodes. Also, the second substrate (often referred to as a color filter array substrate) includes a black matrix layer that prevents light from portions of the first substrate except at the pixel regions, an R/G/B color filter layer for displaying various colors, and a common electrode for producing the image.
The LCD device does not emit light in and of itself. Thus, the LCD device requires an additional light source for emitting light. Especially, in the case of a transmitting type LCD device, it is necessary to provide an additional light source for emitting and guiding light at the rear of the LCD panel. However, the backlight is maintained in the turned-on state during driving the LCD device, thereby increasing power consumption of the LCD device.