The widely used lateral electric field effect display technology (English: In-Plane-Switching Liquid Crystal, abbreviation: English: In-Plane Switching, abbreviation: IPS) is an LCD developed by Hitachi in 1996 Wide viewing angle technology is widely used in the manufacture of LCD TVs and tablet computers. It can effectively improve the chromatic aberration and other problems that occur on TN screens when the viewing angle is poor.
In the late 1980s and early 1990s, TN panel technology was the only viable active matrix LCD technology, and early panel technologies faced challenges Issues with grayscale inversion and high response time. With the development of new technologies in the mid-1990s - the arrival of classic IPS panel technology and VA panel technology, it became possible to solve these shortcomings and be applied to the manufacturing of large-screen panels.
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History
The imaging method patented in 1974 had little success because the inventor was unable to produce a finished product that was superior to TN panel LCDs. micro. Therefore, Guenter Baur and others submitted better technical details in Germany, and obtained patents in the United States and other countries on January 9, 1990. The Fraunhofer-Gesellschaft (see note), where the inventors of this technology work, awarded these patents in Freiburg to the Merck Group of Darmstadt, Germany (a company specializing in the pharmaceutical industry... You Can you believe it? ).
Note: Fraunhofer-Gesellschaft zur F?rderung der angewandten Forschung e. V.) is the largest applied scientific research institution in Germany and Europe. It was founded in On March 26, 1949, it was named after the German scientist, inventor and entrepreneur Joseph Fraunhofer. The Fraunhofer Association has more than 80 research institutes with a research funding of 1 billion euros, and is headquartered in Munich.
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Fraunhofer Society for the Promotion of Applied Research
Shortly thereafter, the Japanese company Hitachi improved the technology and applied for a patent. The leader in this field is Katsumi Kondo, who was working at Hitachi Research Center in 1992. Hitachi engineers worked out various practical details of IPS technology to interconnect arrays of thin-film transistors into a matrix, avoiding undesirable spurious domains between pixels. Hitachi also further improved the acceptability of viewing angles by optimizing the shape of the electrodes. NEC and Hitachi therefore became the earliest manufacturers of this technology.
IPS screen: technical details
IPS technology changes the arrangement of liquid crystal molecular particles and adopts horizontal conversion technology, which speeds up the deflection of liquid crystal molecules while also ensuring The clarity of the picture when shaking is eliminated, which eliminates the blurring and watermark diffusion phenomena that occur when traditional LCD screens receive external pressure and shake. Since the liquid crystal molecules rotate in the plane, the viewing angle performance of the IPS screen is also good, and the viewing angle can be close to 180 degrees in all four axes.
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There are many types of IPS when broken down. Looking at the dense classification...I feel so tired
Of course, IPS is actually this type of screen It is a general term, but if it is broken down, there are many categories.
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Both IPS panels and TN panels use TN liquid crystals. The different characteristics of the two are that the electric fields they apply to the liquid crystal molecules are different: parallel to the TN panel up and down. The way of configuring two conductive plates is different. The electrodes and liquid crystal of IPS liquid crystal are on the same plane (that is, the electric field is parallel to the liquid crystal plane). In the open circuit state, light cannot pass through. When the loop is connected, the liquid crystal molecules twist the light and birefringence occurs and passes through the liquid crystal. flat. Since the electrode and the liquid crystal are on the same plane, there is no directionality, so a viewing angle of 178 degrees up, down, left, and right can be obtained.
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The imaging principle is: linear polarizing filters P and A are in the same direction.
In order to achieve a 90-degree twisted nematic structure of the liquid crystal layer between the two glass plates without applying an external electric field (off state), the inner surface of the glass plate is treated to align at right angles to the liquid crystal molecules. This molecular structure is actually the same as TN LCD. However, the arrangement of electrodes E1 and E2 in IPS technology is different from that in TN technology - because they are on the same plane and on a single glass plate, the electric field they generate is basically the same as this The glass plates are parallel, and the liquid crystal layer is only a few microns thick, so very small compared to the distance between the electrodes.
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The contextual illustration is here~
And because the liquid crystal molecules have positive dielectric anisotropy, and their long axes are parallel to the external Electric field, so in the off state (like on the left above), the incident light L1 will be linearly polarized by the polarizer P. The twisted nematic liquid crystal layer will rotate the polarization axis of the passing light by 90 degrees. Therefore, under ideal circumstances, no light will pass through the polarizer A. In the turned-on state, because a sufficient voltage is applied between the electrodes and a corresponding electric field E is generated, the liquid crystal molecules will be rearranged, just like the one on the right side of the picture above, so that the light L2 can Passed through polarizer A.