LCD Liquid crystal display covers five film types.

1,TN film type LCD LCD screen

Segment code LCD screen, is a LCD display mode, LCD screen has two modes of pen break and dot-matrix, segment code is also called pen break a number is displayed by 8 words, an 8 word is composed of 7 pen segments, can display 0~9 numbers such as calculator, clock, display content are digital.

The process of segmental-code LCD screen is much simpler than that of dot matrix, of course, it can only display relatively simple content. The Chinese characters and graphics of segmental-code LCD screen can only be displayed in a fixed pattern. The numbers can be changed, and all the displays of dot matrix can be changed at will.

2.HTN film LCD LCD screen

Definition: highly twisted nematic type; Feature contrast is high, power consumption is low, drive voltage is low.

Nematic liquid crystal molecules are sandwiched between two transparent glasses. Between the two layers of glass, the orientation of the liquid crystal molecules is deflected by 110 to 130 degrees. The characteristic of this type of LCD is that the dynamic driving performance is not good, but the viewing Angle is wider than the TN type.

3.STN film LCD LCD screen

STN(Super Twisted Nematic) is an electric field that changes the arrangement of liquid crystal molecules twisted above 180 degrees to change the optical rotation state. The applied electric field changes the electric field through the way of successive scanning. In the process of the electric field repeatedly changing the voltage, the recovery process of each point is slow, so that the afterglow is generated. It has the advantage of low power consumption, which has the biggest advantage of saving electricity.

The display principle of color STN is to add a color filter on the traditional monochrome STN LCD, and divide each pixel in the monochrome display matrix into three sub-pixels, respectively through the color filter to display the three primary colors of red, green and blue, then the color picture can be displayed. Different from TFT, STN belongs to Passive LCD, with a maximum display capacity of 65536 types

Color.

It is mainly divided into ordinary STN, FSTN, CSTN and DSTN.

Ordinary STN is the liquid crystal rotating in the LCD screen 180~270 degrees, the LCD screen is pasted above and below the ordinary polarizer, because of the reason of dispersion, the LCD screen background color will show a certain color, common yellow green or blue, that is usually called yellow green mold or blue mold.

FSTN(Film+STN), in order to improve the background color problem of ordinary STN, a layer of compensation film is added to the polarizer, which can eliminate the dispersion and achieve black and white display.

CSTN(ColorSTN), color STN, on the basis of FSTN technology, add a layer of RGB color film, color display, generally a higher number of driving channels.

DSTN(DoubleSTN), double layer STN, one of the driving layer, the other layer for compensation layer, belongs to STN black and white technology, compared with FSTN, the contrast is higher, and can be self-compensation with the temperature dispersion, to achieve a wide temperature range of high contrast.

The display principle of STN type is similar to TN, but the difference is that the liquid crystal molecule of TN torsional nematic field effect rotates the incident light by 90 degrees, while STN supertorsional nematic field effect rotates the incident light by 180~270 degrees. It should be noted here that the pure TN LCD itself only has two situations of light and dark (or black and white), and there is no way to achieve color change. However, if a colorfilter is added to the traditional monochrome STN LCD, and any pixel of the monochrome display matrix is divided into three sub-pixels, and the three primary colors of red, green and blue are displayed through the colorfilter respectively, and then the ratio of the three primary colors is adjusted. You can also display colors in full color mode. In addition, the TN typeLCD display if the larger the screen, its screen contrast will appear poor, but by STN improved technology, it can make up for the lack of contrast.

4.SFTN film LCD LCD screen

5.CSTN film LCD LCD screen

Color display for mobile devices

On the surface, STNLCD only increases the distortion Angle of liquid crystal molecules, but in fact, it is far from so, because the increased distortion Angle makes another characteristic of liquid crystal appear, which is the birefringence I mentioned before. The outside light that strikes the upper plate becomes a beam of linearly polarized light, but the linearly polarized light no longer merely distorts its direction as it passes through the liquid crystal molecular layer. Instead, it splits into two beams -- ordinary light and unusual light -- which interfere with each other on their way out. Thus, STNLCD always presents a certain background color (such as green and blue) when it is not powered up. Therefore, we can see that the display principle of STNLCD is fundamentally different from TNLCD. It uses the birefringence of liquid crystal. People in order to eliminate STNLCD background color to think of a lot of ways, the simplest is to use a exactly the same, but the opposite direction of the two STNLCD box together, so that the interference of two beams of light and compensation each other back, so as to achieve black and white display, this is DSTN(DoubleSTN), but the cost of DSTN is high, The idea was to use a layer of iodine molecules to simulate a liquid crystal cell, so that a thin film (phase phase difference plate) instead of a liquid crystal cell, to achieve a black and white display, called FSTN(FilmSTN). So far, I can say that all black and white phone screens are FSTNS. STNLCD is characterized by wide viewing Angle and large capacity display. Its disadvantage is slow response speed, because the contrast of STN is much lower than that of TN due to the existence of multiplex drive.

The color of STNLCD is what we call CSTN(ColorSTN). It's basically an FSTN screen with a color film. Use RGB three pixels to form a display pixel. The basic display principle of CSTN is exactly the same as that of STN, so it also inherits all the advantages and disadvantages of STNLCD. The slow response is its fatal injury. UFBLCD, which is used in some current Samsung phones, is still a CSTN, but with a slight increase in the full screen transmittal and then interpolation to 65K color, it is still a normal CSTN, UFB, which is just a Samsung concept. Many color phones currently on the market are CSTNS, with only a few high-end color screensTETLCD is for mobile phones. Like G88N8 and T108.