How many display types of monochrome LCD?

- Sep 28, 2020-

LCD monochrome(black and white) screens generally use TN (Twist Nematic) twisted nematic liquid crystal. Its working principle: nematic liquid crystal is sandwiched between two pieces of glass. The surface of this glass is first coated with a transparent conductive film ITO (Indium Tin Oxide) For the purpose of electrodes, the orientation layer PI (polyimide) is coated on the glass with thin film electrodes to make the liquid crystals align in a specific direction parallel to the glass surface. The natural state of the liquid crystal has a 90-degree twist. The electric field can make the liquid crystal molecules rotate. The birefringence of the liquid crystal changes with the direction of the liquid crystal. As a result, the polarized light passes through the TN-type liquid crystal and the polarization direction rotates. As long as the appropriate thickness is selected so that the polarization direction of the polarized light is changed by just 90 degrees, two parallel polarizers can be used to make the light completely unable to pass. And a sufficiently large voltage can make the direction of the liquid crystal parallel to the direction of the electric field, so that the polarization direction of the light will not change, and the light can pass through the second polarizer.

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Thus, the brightness of the light can be controlled. Color liquid crystal displays generally use TFT (Thin Film Transistor) thin film transistor liquid crystal displays. The principle is to deposit a layer of silicon on a glass substrate and form a transistor array through printing photolithography and other processes. Pixels are equipped with a semiconductor switch, and its processing technology is similar to a large-scale integrated circuit. Then pour the liquid crystal between the two pieces of glass. Since each pixel can be directly controlled by dot pulses, each node is relatively independent and can be continuously controlled. This design not only improves the response speed of the display, but also At the same time, it can accurately control the display gray level, so the color of TFT liquid crystal is more realistic, which is called true color. TFT is divided into polycrystalline silicon, amorphous silicon and monocrystalline silicon. In March 2004, Samsung released a liquid crystal display device for mobile phones, called UFB (Ultra Fine & Bright) LCD, with ultra-thin, high-brightness specialty.


LCD black and white screens are classified according to product types: TN, HTN, STN, FSTN, DFSTN, VA... etc. LCD black and white screens are divided into reflective, semi-transmissive and full-transmissive types according to their display methods.


1. A reflective plate is added behind the bottom polarizer of the reflective LCD. It is generally used outdoors and in well-lit offices.


Transflective LCD is between the above two. The bottom polarizer can partially reflect light. Generally, it also has a backlight. When the light is good, the backlight can be turned off; when the light is poor, the backlight can be turned on. Use LCD .


2. The bottom polarizer of Transmissive LCD is a transmissive polarizer, which requires continuous use of the backlight, which is generally used in poor light environments.


LCD black and white screens are divided into positive (Positive) and negative (Negative) according to the display mode. Compared with LCD monitors, color LCD screens have more advantages in terms of brightness, power consumption, viewing angle and refresh rate. The power consumption ratio of LED to LCD is about 10:1, and the higher refresh rate makes LED have better performance in video, can provide a wide viewing angle of 160°, and can display a variety of text, numbers, and color images And animation information, can also broadcast TV, video, VCD, DVD and other color video signals, and multiple display screens can also be broadcast online. The reaction speed of a single element of an organic LED display is 1000 times that of an LCD liquid crystal screen. It can also be illuminated under strong light and can adapt to a low temperature of minus 40 degrees. Using LED technology, a thinner, brighter, and clearer display than LCD can be manufactured, which has a wide range of application prospects.


1. Positive LCD presents black characters on a white background, which is best displayed in reflective and transflective LCDs;


2. Negative LCD presents white characters on a black background. It is generally used for full-transparent LCD screens. With backlight, the fonts are clear and easy to read.