For some customers, such as small advertising screen, small meeting display screen, customers will still struggle to choose between LCD and LED display. In the following article, we will explain the difference between LCD and LED in detail, so that customers will not have to worry about choosing a small screen.
1.What is LCD?
Liquid Crystal Display (LCD) is short for Liquid Crystal Display (LCD). There are mainly TFT, UFB, TFD, STN and other types. Its structure includes plastic sphere, glass sphere, frame adhesive, glass substrate, upper polarized plate, directional layer, liquid crystal, conductive ITO pattern, conduction point, IPO electrode and lower polarized plate.
1.1 Basic Structure of LCD
Take Colliers Hi-Tech LCD advertising machine as an example, it uses the most well-known TFT-LCD is a thin film transistor LCD display.Its basic structure is placed in the middle of the two pieces of parallel glass liquid crystal box, the substrate glass set on thin film transistor (TFT), on the base plate glass on set color filter, signal and the voltage change on the thin film transistor to control the rotation direction of the liquid crystal molecules, so as to achieve control of each pixel display emergent polarized light or not and to achieve.
1.2 TFT structure
The principle of liquid crystal display is that liquid crystal under the action of different voltage will show different optical properties. Liquid crystal display is composed of many liquid crystals arranged in an array, in a monochrome LCD screen, a liquid crystal is a pixel (the smallest unit that can be displayed on a computer screen), and in a color LCD screen, each pixel is composed of red, green and blue liquid crystals.
At the same time, it can be considered that there is an 8-bit register behind each liquid crystal, and the value of the register determines the brightness of each of the three liquid crystal cells. However, the value of the register does not directly drive the brightness of the three liquid crystal cells, but is accessed through a “palette”.
It is not practical to equip each pixel with a physical register. In fact, only one line of registers is provided. These registers are connected to each line of pixel in turn and loaded into the contents of the line.
2.What is LED?
LEDs stands for light emitting diodes. To put it simply, LCD and LED are two different display technologies. LCD is a display made up of liquid crystals, while LED is a display made up of light-emitting diodes.
We will not explain the principle and composition of LED here.
3.The difference between LCD and LED
1. The power consumption ratio of the LED display to the LCD display is about 1:10, So the LED display is more energy-efficient.
The LCD display composed of liquid crystals, which are a substance between solid and liquid.As the LCD display cannot emit light by itself, and it can only be illuminated with the help of an additional light source.
The LCD display has a backlight layer and a liquid crystal layer, and then the thickness of LCD display will be thicker than the LED display.
Moreover,the principle of the LCD display brightness, they are realized by the brightness of the backlight tube behind the panel. Therefore, the lamp tube needs to be designed more so that the light will be uniform. But the more lamps are used, the more increasing power consumption.
The LED display composed of light-emitting diodes,which are self-luminous and each pixel can project light of the three primary colors of red, green and blue, so the display effect is more vivid and full.
Since the LED lamp is very sensitive to the passage of current, a very small current can make it emit light, and it has a long life. It flickers for a long time without damage.
Each LED pixel works independently, and then light up some LED pixels individually, so the power consumption of the LED display will be lower than the LCD display.
2. LED provides a view of 160 ° wide.
The size of the viewing angle directly determines the number of the screen audience，so the larger the better.The size of the viewing angle is mainly determined by the packaging method of the core.
The viewing angle is the angle between the two viewing directions and the normal direction of the same plane when the brightness of the viewing direction drops to 1 / 2 of the normal brightness of the LED display screen.
It is divided into horizontal and vertical angle of view, which is also called half power angle.The angle of view can be measured with professional instruments.
3. LED display can display all kinds of text, numbers, color images and animation information, and can play TV, video, VCD, DVD and other color video signals.
Therefore, it is widely used in stadiums, airports, stations, banks, hospitals, public squares, commercial places, residential communities and so on. The LED display includes synchronous display and asynchronous display.
The asynchronous display is graphic LED display. It can display text, graphics, pictures and other information.The graphic LED display can be displayed offline.
The synchronous display is video LED display. It can display all kinds of information in real time and synchronously, such as two-dimensional or three-dimensional animation, video, TV, video disk, live scene and so on.
4. LED has a higher refresh rate and better performance in video.
LED and LCD have different light emitting principles. The pixels of LCD can be regarded as separate switches. Since the liquid crystal itself does not emit light, the LCD screen needs another backlight source. Only perform a refresh operation to display a stable image. The LCD screen refreshes the image at a constant frequency. A lower refresh rate, not less than 24Hz, can ensure the smoothness of the image.
LED is Light Emitting Diode, no need background light source, and each pixel is a light-emitting point; LED dot matrix and PC panel are composed of red, blue, white, and green to display text and pictures, animation, video, content display screen.
It uses low-voltage scanning drive, it has: high brightness, miniaturization, long life, low operating voltage, low power consumption, stable performance and impact resistance.
LED has a higher refresh rate. On the other hand, because there is no backlight, it is better in black display. The display screen is bright in color and strong in three-dimensionality. It is as static as an oil painting and as moving as a movie.
5. The reaction speed of each unit element of the LED display is 1000 times faster than the LCD liquid crystal screen.
According to the use environment, LED display screen is divided into indoor display screen and outdoor display screen.
The brightness of the indoor LED display is generally between 600~1000nits. The outdoor LED display has a high brightness, around 4500~7000nits. Even under strong sunlight, the content played on the LED display can be seen clearly.
The brightness of LCD liquid crystal screen is far lower than the LED display, even the brightness of the LCD liquid crystal screen used in the high-end market can only reach 700nits.
In addition, because of the high waterproof performance, the strong anti-ultraviolet material and the protection level above IP65, the outdoor LED display can be used in various harsh natural environments such as high temperature, heavy rain, typhoon, thunder and lightning, and low temperature.
Even in a low temperature of minus 40 degrees, the LED display can still operate stably. it is obvious that the application environment of LED display screens is far wider than the LCD liquid crystal screen.
6. The LED display can be a seamless whole screen, while the LCD screen needs to be spliced and has large gaps
LED display in the indoor small screen, many customers will choose LCD screen splicing to save costs.But the brightness of LCD can not be very high, the most important thing is that it can not be as free and seamless as LED.
In conclusion, the difference between LCD and LED are varies from the displaying performance, parameters, structures, functions and so on. For more professional technical articles about LED, welcome turn to our LED Display FAQ!