How LED backlit displays work

LED backlit displays are now popular in every aspect of our lives, from TVs, computer monitors to mobile phone screens, and they are almost everywhere. But have you ever been curious about how this "LED backlight" makes the screen light up? Today, we will use the most easy-to-understand way to reveal the working principle of LED backlit displays. Provide you with a guide to the application of LED display in the mall.

The "heart" of LED backlit display: LED light beads

First of all, we have to know that the LED backlit display itself does not "glow". It is a "passive" display technology, that is, it requires an external light source to illuminate it. This external light source is what we call LED (light emitting diode) lamp beads. Let you understand how LED light beads work.

Imagine your monitor is like a translucent painting, which has no color and no light. In order to see the content of this painting, we need to shoot a beam of light behind it. LED backlight is this illuminated "flashlight".

How LED backlight works: from "light" to "image"

So, how do these LED light beads turn light into the image we see? This involves several key components working together:

LED light bead array: As the name suggests, these are small LED bulbs densely arranged behind the display. The light they emit is white. Here are 3 LED light bead specifications.

Important source: The original LED backlighting technology mostly used side-in (Edge-lit), that is, LED light beads are located at the edge of the display, and the light is evenly guided to the center of the screen through the light guide plate. Now the higher-end display adopts direct-lit type, and LED light beads are directly distributed evenly behind the screen, which can achieve more finer regional light control and improve contrast. Here is an analysis of LED backlight display technology.

Light Guide Plate (LightGuidePlate-LGP): If it is a side-in LED backlight, the light will first enter a transparent light guide. The light guide plate acts like a "light pipe", which can evenly spread the light on the side to the entire screen area, ensuring the consistent brightness of the picture.

Diffusing film and prism film: Even with a light guide plate, the light may still be not uniform enough or the brightness is not high enough. At this time, the diffusion film and the prism film come in handy. The diffusion film can further soften the light and eliminate possible bright spots or dark areas. The prism film can focus light and improve the overall brightness of the screen.

Liquid CrystalLayer: This is the "soul" of LED backlit displays. The liquid crystal itself does not emit light, but it has a very magical characteristic - under the control of voltage, it can change the arrangement direction of its own molecules, thereby controlling whether the light passes or not and the deflection angle of the light.

Important source: The discovery and application of LCD technology is an important milestone in the development of modern display technology. You can think of liquid crystal molecules as countless tiny "blinds", which can be opened, closed or half open through voltage control, thus determining how much backlight can pass through them.

Color Filter: When the backlight passes through the liquid crystal layer, it also needs to pass through the color filter. Each pixel point consists of three subpixels: red (R), green (G), and blue (B). The color filter is responsible for "dyeing" the penetrating white light, so that each sub-pixel will present the corresponding color.

Polarizer: There is a polarizer in front and behind the liquid crystal layer. The function of a polarizer is to filter out light in a specific direction. By changing the polarization direction of light and combining with a polarizer, the liquid crystal layer can achieve precise control of the amount of light throughput.

To summarize this process:

LED lamp beads emit white light → The light becomes uniform and bright through the light guide plate, diffusion film, and prism film → The white light penetrates the liquid crystal layer (the liquid crystal molecules control the amount of light through the electrical signal) → It is "dyeed" through the color filter → Finally, it forms the colorful image we see.

Advantages of LED backlit displays

The reason why LED backlight can replace traditional CCFL (cold cathode fluorescent lamp) backlight has the following significant advantages:

Thinner: LED light beads are small in size, making the display thinner and lighter.

More power saving: LEDs have high luminous efficiency and lower energy consumption, which is in line with the trend of modern green and environmental protection.

Higher brightness and better contrast: LEDs can provide higher brightness, and the direct-down LED backlight can also achieve regional light control (Local Dimming), making the dark part darker and the brighter part brighter, thereby greatly improving the picture contrast.

Longer lifespan: LED beads generally have longer lifespan than CCFL lamps.

Environmental protection: It does not contain harmful substances such as mercury.

I hope that through this article, you will have a clearer understanding of the working principle of LED backlit displays. Next time you see a bright display screen, you might as well think about these LED light beads and precision LCD technology that work silently behind it. They have jointly created the wonderful world in front of us.

Thank you for watching. I hope we can solve your problems. Sostron is a professional LED display manufacturer. We provide all kinds of displays, display leasing and display solutions around the world. If you want to know: Shopping mall LED screen installation plan: Create brand scenario. Please click read.

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