The TN type LCD display panel has been widely used, especially in industries such as clocks, electronic clocks, calculators, and automotive instruments. The focus of this article is to explain what TN panel means, the structure and working principle of TN type LCD display screen, hoping to be helpful to everyone.
1, What does TN panel mean
TN panel is a commonly used liquid crystal panel, TN (Twisted Ne * * tic) twisted nematic liquid crystal, whose liquid crystal molecules can undergo 90 ° torsion at both ends of the panel with and without voltage. The liquid crystal display screen manufactured using TN liquid crystal is called TN type liquid crystal screen. In fact, TN type LCD screens can be divided into static or passive drives, mainly used for displaying characters and simple images on TN type pen segment, character and dot matrix LCD screens, as well as TN-TFT display screens driven by active matrix drive (TFT thin film field-effect transistor), which are commonly referred to as ordinary TFT LCD screens. Generally speaking, unless otherwise specified, TN type LCD screens refer to pen segment, character, and dot matrix LCD screens that use static or passive driving. These types of LCD screens are mostly black and white display screens.
2, Structure of TN type LCD display screen
At present, commonly used display devices such as calculators, digital instruments, and electronic clocks are all TN type devices.
Stack two pieces of glass with transparent electrodes on top and bottom, spaced about 10mm apart, and seal them together with epoxy resin. The sealing frame has an injection port, through which the liquid crystal material is injected into the liquid crystal box in a vacuum environment. Then, seal the injection port with resin, and attach a polarizing film with polarization directions perpendicular to each other on the upper and lower surfaces. Add a reflective plate at the bottom, Even if the LCD display device is made.
In the TN display screen, a directional film (coordination film) is also coated on the inner surface of the glass, and directional treatment is carried out. The liquid crystal molecules are arranged parallel to the glass surface in the box. Due to the orientation of the inner surface oriented layers of the upper and lower glass sheets being perpendicular to each other, liquid crystal molecules are twisted 90 ° between the two glass sheets, which is the origin of the name twisted nematic liquid crystal display device.
3, What is the working principle of TN type LCD display screen
The grooves on the two polarizing planes are perpendicular to each other (intersecting at 90 °), which means that if molecules on one plane are arranged in a north-south direction, then molecules on the other plane are arranged in an east-west direction. Molecules located between the two planes are forced into a 90 ° twisted state. Due to the propagation of light along the direction of molecular arrangement, light is also twisted 90 ° when passing through the liquid crystal.
In the absence of an electric field, the incident light passes through the polarizing film and passes through the liquid crystal layer. The polarizing light is rotated 90 ° by the molecular twisted arrangement of the liquid crystal layer. When leaving the liquid crystal layer, its polarization direction is exactly the same as the direction of the other polarizing plate, so light can pass smoothly. In this case, the liquid crystal cell is quite transparent, and we can see the electrodes of the reflecting plate.
When liquid
