Basic knowledge of LCD display

1.Liquid Crystal Display (LCD)

The objective of light, thin, short, and tiny is now being pursued by scientific and technical information goods, and display devices with a long history as computer peripherals are of course no exception. Traditional display technologies, such as CRT image tube displays and LED display panels, are all prone to issues like excessive size or high power consumption, which cannot match the expectations of users in reality. The advancement of liquid crystal display technology perfectly fits the direction that information goods are currently taking. Users may take advantage of the ideal visual environment whether it has a right-angle display, low power consumption, compact size, or no radiation.

2.The invention of liquid crystal

We must begin with the definition of "liquid crystal" in order to understand the history of liquid crystal displays. Frederick Friedrich Reinitzer, an Austrian botanist, made a unique discovery in 1888. He took a substance known as spirotoluate from plants, and when heating studies were being conducted for this substance, he unintentionally discovered that this substance has two melting points at various temperatures. Similar to the colloidal solution of soapy water, it exists in a condition halfway between the liquid and solid states that we are familiar with, but only within a narrow temperature range. Liquid Crystal, which refers to liquid crystal material, was afterwards given to the state. Although the liquid crystal was first developed in 1888, it wasn't until 80 years later that it became truly useful for everyday items.

Engineers found that liquid crystal molecules would be changed by voltage, altering their chemical arrangement and reflecting incoming light. This discovery was made in 1968 at the Shanov R&D Center of the RCA Corporation (the company that invented radio and television) in the United States. the occurrence. This idea was used by RCA to create the first liquid crystal display screen in history. Since then, digital camera displays, calculators, electronic watches, mobile phone screens, devices used in hospitals (due to radiation metering issues), and other common electronic items have all included liquid crystal display technology.

Interestingly, liquid crystals were discovered before vacuum tubes or cathode ray tubes, although nothing was known about this phenomena at the time. Joe Castellano, a scientist, didn't release his first book until 1962, but he had already written several others. Although these two technologies, like the picture tube, were developed by the RCA corporation in the United States, Sony and Sharp, respectively, took them further in Japan.

3.Understanding of LCD basics

Liquid crystal displays are passive displays; they can only make use of ambient light as they are unable to produce their own light. The energy needed to show patterns or letters is quite low.

LCD has improved as a display technology precisely because of its low power consumption and compactness. An organic compound with both liquid and solid qualities serves as the basis for liquid crystal displays. In the liquid crystal cell, its rod-like structure is typically placed in parallel, but an electric field can vary the direction in which it is structured.

When a voltage is applied to the electrodes, the LCD is in the "ON" state and the direction of the long axis of the liquid crystal molecules is in the "OFF" state for positive TN-LCDs. When no voltage is applied to the electrodes, the LCD is in the "OFF" state and light can pass through the LCD to be in a white state. The LCD is in a dark condition when the direction of the electric field is aligned with that of the light, which is unable to travel through it. Different patterns may be shown by providing a voltage to the electrodes in specific locations.

Because the liquid crystal's twist angle is greater in STN-LCD displays, the contrast ratio is higher and the viewing angle is broader. Based on the birefringence principle, STN-LCD displays are produced. The typeface is blue, which turns into a yellow-green mode, and the dominant color is often yellow-green. The basic color will become gray and mold into a gray color when a violet polarizer is used. The basic color will almost become white when used with a polarizer and compensating film. At this point, STN transforms into FSTN, a black-and-white mode. The impact will be greater if the polarizer of the first three modes is rotated by 90 degrees to form a blue mode.

4.Types of LCD monitors

A sort of flat-panel display is a liquid crystal display, sometimes called an LCD (Liquid Crystal Display) in English. It may be split into three categories, including static drive (Static), simple matrix drive (Simple Matrix), and active matrix drive (Active Matrix), based on the driving mode. These include twisted nematic (Twisted Nematic; TN), super twisted nematic (Super Twisted Nematic; STN), and other passive matrix-driven liquid crystal displays. Active matrix type can be roughly divided into two categories: thin film transistor type (Thin Film Transistor; TFT), and two-terminal diode type (Metal/Insulator/Metal; MIM).

Due to variations in the liquid crystal molecules' twisting principles, TN, STN, and TFT type liquid crystal displays have different viewing angles, colors, contrasts, and animation display quality. The active matrix driving technology is primarily based on the thin film transistor type (TFT), which is mostly utilized in laptop computers, animation, and image processing goods, in terms of the breadth and level of application of the present liquid crystal display technology. Twisted nematic (TN) and super twisted nematic (STN), which are now dominant in the pure matrix drive technology, are mostly used in word processors and consumer goods. TFT liquid crystal displays among them have relatively high capital expenditure and technical needs, whereas TN and STN have comparatively low technical and financial requirements.