What is the difference between IPS type and TN type

- Oct 28, 2020-

IPS technology is a display technology successfully developed by Hitachi, Japan in 1996. It is an LCD wide viewing angle technology, which is widely used in LCD-TV manufacturing, which can effectively improve the color difference that appears on TN screens when the viewing angle is poor. And other issues. Display principle


Both IPS type and TN type use nematic liquid crystals. The difference between the two is that the electric field applied to the liquid crystal molecules is different:

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The TN type electrode is on the two substrates, the direction of the applied electric field is perpendicular to the substrate, and the liquid crystal molecules move in parallel and perpendicular to the substrate; the IPS type applies the electric field method horizontally, so the liquid crystal molecules are parallel to the substrate During torsional movement, the liquid crystal molecules without an electric field are aligned in parallel to the substrate (homogeneous), and the upper and lower polarizers are arranged in a 90-degree cross and always remain vertical. The polarization axis of the bottom polarizer is the same as the image of the liquid crystal molecules. The incident light travels through the parallel arrangement of the liquid crystal layer and travels in a straight line without changing the direction of travel. The emitted light cannot pass through the upper polarizer, so it presents a opaque black state, and an electric field is applied. Later, the liquid crystal molecules will be twisted, causing birefringence in the liquid crystal layer, which will change the direction of the incident light, passing through the upper polarizer, and presenting a light-transmitting state. When the liquid crystal molecules cross the substrate and make a torsional movement, and no electric field is applied, when the liquid crystal molecules are arranged at less than the inclination angle, the viewing angle of the black state is increased, resulting in a wider viewing angle of the brightness ratio.


Once the transistor on the display is burned and becomes a dead spot, the dead spot of the general display will become a bright spot, but the IPS display will become a black spot with no light. The hard panel is very suitable as a touch screen. Excellent color performance and viewing angle.


However, a better display comes at a price. The price of IPS technology is a slower response rate, about 50 milliseconds. In addition, displays using IPS technology are also very expensive. Therefore, after IPS was launched in 1996, new developments continued:


In 1998, Hitachi introduced S-IPS (Super-IPS). In addition to the original technology of IPS, the response rate was also improved. In 2002, Hitachi launched AS-IPS again, which greatly improved the light-to-dark ratio.


Power consumption is higher than normal screens. Although the viewing angle has been increased to 170 degrees, other properties have not been improved at all, so it is not worth the money. Compared with the VA series panels, the contrast ratio is poor, the performance is not good in black and dark colors, and it is easy to have light leakage. The reaction speed is slow, and it is easy to have afterimages.