Generally, TFT-LCD consists of upper substrate module, lower substrate module, liquid crystal, driving circuit unit, backlight module and other accessories. The lower substrate module mainly consists of lower glass substrate and TFT array. The upper substrate module consists of upper glass substrate, polarization plate and film structure covered with upper glass substrate. The liquid crystal is filled in the gap formed by upper and lower substrate.
On the inner side of the lower glass substrate, there are a series of conductive glass microplates corresponding to the pixels of the display, TFT semiconductor switching devices and vertical and horizontal lines connecting semiconductor switching devices, which are formed by microelectronics manufacturing processes such as photolithography and etching.
On the inner side of the upper glass substrate, there is a transparent conductive glass plate, which is generally made of Indium Tin Oxide (ITO) material. As a common electrode, it forms a series of electric fields with many conductive microplates on the lower substrate.
If LCD is color, there are three primary color (red, green, blue) filter units and black dots between the common conductive plate and the glass substrate. The function of black dots is to prevent light from leaking from the gap between the pixels. It is made of opaque materials. Because of its matrix distribution, it is called black dot matrix.
