According to the arrangement of liquid crystal molecules, what are the common types of liquid crysta

According to the arrangement of liquid crystal molecules, common liquid crystal displays are divided into: tn-lcd, stn-lcd, dstn-lcd with narrow viewing angle; IPS, VA, FFS, etc. with wide viewing angles. We often ask how big is the dot distance of the LCD monitor, but most people don't know how this value is obtained, now let's understand how it is obtained.

For example, the viewing area of a 14-inch LCD is 1024 768, then the dot pitch is equal to: the visible width of horizontal pixels (or the viewing height of vertical pixels), that is, or. The radiation of liquid crystal monitors is much lower than that of CRT monitors (just low, not completely devoid of radiation, electronic products are more or less radiated), which is a boon for people who work in front of a computer all day.

The maximum brightness of a liquid crystal display is usually determined by a cold cathode ray tube (backlight), and the brightness value is generally between 200 and 250 cd m2. Technically, high brightness can be achieved, but this does not mean that the higher the brightness value, the better, because too high brightness of the display may cause eye injury. LCD is a substance between solid and liquid states, and it cannot emit light on its own, requiring the help of an additional light source.

Therefore, the number of lamps is related to the brightness of the liquid crystal display. The earliest LCD display only had two tubes, and until now, the lowest of the popular type is four lights, and the high-end is six lights. The four-lamp design is divided into three placement forms:

One is that there is a lamp tube on each of the four sides, but the disadvantage is that there will be a black shadow in the middle, and the solution is to arrange the four lamps from top to bottom, and the last one is the "U" shaped placement form, which is actually two lamps produced by two lamps in disguise. The six-lamp design actually uses three lamps, and the manufacturer bends the three lamps into a "U" shape and then places them in parallel to achieve the effect of six lamps.

1. CRT, cathode ray tube display. The cathode ray tube is mainly composed of five parts: an electron gun, a deflection coil, a shadow mask, a phosphor layer and a glass shell.

CRT flat screen display has the advantages of large viewing angle, no dead pixels, high color reproduction, uniform chromaticity, adjustable multi-resolution mode, and extremely short response time.

2. LCD, liquid crystal display. The working principle is that there are many liquid crystal particles inside the display, they are regularly arranged into a certain shape, and the color of each side of them is different. It can be restored to any other color, and when the display receives the display data from the computer, it will control each liquid crystal particle to rotate to a different color surface to combine into different colors and images.

3. LED, LED side display. It is a display screen that controls the display of semiconductor light-emitting diodes and is used to display various information such as text, graphics, images, animations, video signals, etc.

D, 3D display. The "parallax fence" is used to make each eye receive different images to create a three-dimensional effect. The flat-panel display provides two sets of images with different phases to form a three-dimensional image.

5. PDP, plasma display. The imaging principle is that the imaging principle of plasma display technology is to arrange thousands of small sealed low-pressure gas chambers on the display screen, and make it emit ultraviolet light invisible to the naked eye through current operation and excitation, and then the ultraviolet light hits the red, green and blue phosphors on the glass behind it to emit visible light that can be seen by the naked eye, so as to imaging.

The LCD panel is mainly composed of the following eight parts:

1. Backlight (or backlight module):

Since liquid crystal molecules cannot emit light on their own, if you want to appear in a picture, the liquid crystal screen needs a special light source to provide light, and then the liquid crystal molecules are deflected to produce different colors. The role of the backlight is to provide light energy.

2. Two polarizers on the upper and lower layers:

The role of a polarizer is to allow light to pass through in one direction.

3. Two glass substrates on the upper and lower floors:

The glass substrate is not just two pieces of glass, it has a groove structure on the inside and adheres to a alignment film, which allows the liquid crystal molecules to be neatly arranged along the groove. On both sides of the upper and lower layers of glass, TFT thin-film transistors and color filters are attached.

4. ITO transparent conductive layer:

Its role is to provide conductive pathways, which are divided into pixel electrodes (P-class) and common electrodes (M-class).

5. Thin-film transistor (what we often call TFT):

Often said TFT-LCD, it actually refers to this thin film transistor, its role is similar to a switch, TFT can control the signal voltage on the IC control circuit, and transport it to the liquid crystal molecule, determine the angle of deflection of the liquid crystal molecule, so it is a very important component.

6. Liquid crystal molecular layer:

It is the most important element to change the polarization state of light, and its alignment and polarization state are determined by the combination of electricity and elastic forces.

7. Color filter:

The light deflected by the liquid crystal molecules can only display different gray scales, but cannot provide the three primary colors of red, green and blue (RGB), while the color filter is composed of three kinds of RGB filters, and each color and brightness are adjusted by mixing the three. Each pixel in the LCD panel is composed of three dots: red, green, and blue, and each color dot has a different grayscale variation.

8. a frame glue; It is to make the upper and lower layers of glass substrates in the LCD panel firmly glued together, and the entire internal system is "isolated" from the external connection to prevent dust from entering and affecting the color effect.

1. Classification according to the geometry of liquid crystal molecules:

It can be divided into rod-shaped molecules, saucer-shaped molecules, strip-shaped molecules, etc., in addition to bowl-shaped molecules, dovetail molecules, etc.

2. Classification according to the size of liquid crystal molecules

It can be divided into small molecule liquid crystal (small molecular weight, mainly used in liquid crystal display), polymer liquid crystal (large molecular weight, mainly used in high-strength materials).

3. Classification according to the way liquid crystal states are formed:

It can be divided into thermogenic liquid crystals, lysotropic liquid crystals, and amphoteric liquid crystals.

Thermally induced liquid crystals: This kind of liquid crystals exist in a certain temperature range, and the thermally induced liquid crystals that exist stably at temperatures above the melting point of compounds are called interchangeable liquid crystals; In some cases, the liquid crystal state only exists stably at a temperature below the melting point, and the liquid crystal state can only be obtained as the temperature decreases, and this type of thermally induced liquid crystal is called a single variable liquid crystal.

Lysotropic liquid crystals: These liquid crystals are formed by the action of polar (amphiphilic) compounds and certain solvents (such as water), which are present in certain regions and vary with concentration and temperature.

Amphoteric liquid crystals: under certain conditions, lysotropic and thermoevogenic liquid crystals can be formed, such as alkali metal salts of some long-chain fatty acids.

1.Cellulose liquid crystal 2Chitin liquid crystal 3Ferroelectric liquid crystal 4Disc liquid crystal 5Halogenated liquid crystals.

There is a misunderstanding among ordinary consumers about hard screens, thinking that hard screens are adding a layer of hard protective film to the LCD panel. In fact, the real hard screen refers to the way the liquid crystal molecules are arranged differently from the VA soft screen. The reporter learned through the home appliance industry association that the IPS hard screen mainly has significant advantages in dynamic clarity, color reproduction effect, viewing angle, etc.

Widely used, it is also the most inexpensive, it is TN, and some of the better ones are IPS and MVA wide viewing angle panels, TN is cheap, but the viewing angle range is small, and the color performance is not good enough; The latter two outperform the former in all aspects, but are high.

The LCD screen is composed of the following parts: