The display principle of a thin film transistor liquid crystal display (TFT-LCD) is as follows. Thin film transistors (TFTs) are used to control arrangement of liquid crystal molecules between two glass substrates by producing and controlling voltage. The liquid crystal material is capable of generating gray scale due to its photoelectric property. With the aid of the color filter (CF), a full range of colors can be displayed.
The liquid crystal panel of a TFT-LCD mainly comprises an array substrate, a color filter substrate, and a liquid crystal layer disposed therebetween, wherein a spacer is provided to maintain a predetermined space, and a seal is applied to form a liquid crystal cell.
Wide application of TFT-LCD in mobile devices has created an increasingly high demand for much thinner and lighter LCD screen. However, bending tends to occur in a glass substrate by its own gravity, and the extent of its bending is inversely proportional to its own thickness. Therefore, the thinner the glass substrate is, the greater the bending amount will be. If excessive bending occurs, the glass substrate may be cracked or broken, and as a result, patterns on the glass substrate may be distorted accordingly. At present, in mainstream process for a TFT-LCD, glass substrates with a thickness of 0.5 mm˜1.0 mm are used to manufacture the array substrate and the color filter substrate, hence producing a liquid crystal cell with a thickness of 1.0-2.0 mm.
To facilitate the application of TFT-LCD in mobile devices, liquid crystal cell substrates manufactured by LCD factories usually need to be subjected to a thinning process, for example, through hydrofluoric acid etching or mechanical polishing, so as to reduce the cell thickness from 1.0˜2.0 mm to 0.5˜0.6 mm. However, cleanliness requirement in a thinning process is far less than in a LCD manufacturing process, thus resulting in some product appearance defects, such as, scratches, protrusions and stains. On the other hand, the thinning process also adds the cost for manufacturing a LCD. Besides, waste water from the thinning process may bring serious environmental pollution.