Frequently Asked Questions
What are LEDs ?
LEDs are light emitting diodes. These are electronic components that convert electrical energy directly to light through the movement of electrons within the material of the diode. LEDs are important because due to their efficiency and low energy, they are beginning to replace most conventional light sources.
How is light produced in an LED?
Light emitting diodes produce light by the movement of electrons between the two terminals of diode, which occur by a process called electroluminescence. When a light emitting diode is electrically connected, electrons start moving at the junction of the N-type and P-type semiconductors within the diode.
When there is a jump over of electrons at the p-n junction, the electron loses a portion of its energy. In regular diodes this energy loss is in the form of heat. However, in LEDs the specific type of N and P conductors produce photons (light) instead of heat. The amount of energy lost defines the color of light produced.
Why are LEDs considered green technology?
LEDs are more efficient than most other light sources, so they usually consume less energy for a given task or at a spesific light output.
Also, they do not contain hazardous materials such as toxic mercury. Moreover, LEDs have a longer lifespan and hence reduce the frequency of disposal of lamps.
How can we identify the quality of LED displays
The degree of brightness brings people a direct sense. Once we see the LED display, we can sense it. Do not consider that the higher the brightness, the better the showing effect. The showing effect depends on the using environment and viewing distance. For indoor displays, it is usually about 1000nit. For outdoor ones, it is usually larger than 6000nit. For semi-outdoor ones, it is usually between 2500nit and 5000nit. High resolution ones require even lower brightness, usually about 100nit to 300nit. In a word, the most suitable brightness is the one that not only makes audiences see images clearly in different environments but also does not hurt their eyes while watching for a long time.
When the image colors are not the same as or different with those of the real materials, the picture will lose its fidelity. This is related to the color temperature of white balance. If people watch LED displays directly, the suitable color temperature of white balance is between 6500K to 8000K. If the LED displays are transmitted by TV stations, the color temperature needs to be adjusted to about 5500K. In this way, the pictures on LED displays will be real after transmitted by video cameras.
As for the display equipments, the larger the viewing angle, the better the showing effect, and of course the larger the viewing scope. The viewing angles can be divided into the horizontal one and the vertical one. Up to now, for indoor full-color LED displays, the horizontal one and the vertical one can be larger than 140° and 100° respectively. For outdoor full-color LED displays, the horizontal one and the vertical one can be larger than 100° and 90° respectively. On the basis of seeing pictures clearly and completely within the scope of viewing angle, colors can not be different while watching from different viewing angles. This is mainly related to the arrangement of the RGB chips during the encapsulation of LED lamps.
When the sense of layers on the screen is not good and there is the phenomenon of losing pixels compared with materials, this means that the gray level is low and the screen can not show the materials clearly in a real way. The professional testing way is to use gray scale strips, through which people can see the gray level clearly. Up to now, enterprises can realize 16bit gray scale. In the future, it will reach 18bit.
If flicker appears when people watch LED displays and if dark lines appear when we use cameras to make a shot, it means the refresh rate is low. The refresh rate larger than 300Hz will not influence people’s viewing effect. However, if the showing effect is good while using cameras or video cameras, the refresh rate will be above 2000Hz.
When we watch pictures on LED displays, sometimes we will feel they are a little bit white and gray, like gauze covering on them. This means their contrast is low. Usually, the contrast can not be lower than 1000:1. The contrast is mainly related to the encapsulation of LED lamps and the design of module masks. The contrast of LED lamps on black holders is much higher than that of LED lamps with white holders.
The appearance of spots and mosaic on LED displays mainly related to the brightness and color uniformity of LED lamps. We can check the brightness and color uniformity of LED displays by testing their RGB and white colors.
LED vs.LCD: What's the Best Option for Your Video Wall ?
There are a variety of display options for video walls today. The two most common are LED displays and commercial LCD panels.
Where can you actually use and LED Display? They’re ideal for large outdoor displays where brightness is important but image quality and resolution isn’t as important (due to viewing distance). However… For indoor video walls or for video walls where resolution and visual performance are important, Large Format Displays (LFDs) are required.
Commercial large format displays with zero bezel, narrow bezel or ultra narrow bezel are the preferred option for video walls. These can be LCD or LED (typically OLED or MicroLED).
Here is the deal. LED based commercial displays tend to offer high resolution and better brightness and a wider range of colors and typically have slimmer bezels. However they are also very significantly more expensive than backlit LCD displays.
As a result, large format LCD commercial displays continue to be the preferred option for most video wall systems today. 55″ is one of the most common sizes but 60″ and even 70″ displays are available as well.
Can I make a video wall with TV's?
Consumer TV’s have a few potential problems worth understanding: They have wider bezels than commercial displays and they also tend to have a thicker bottom bezel. Why does this matter? Well, this creates the risk of an uneven bezel line where the lines created by the bottom of the displays are thicker than the vertical lines between panels.
Here is how to avoid this:
One way is to flip the top row of displays so they are upside down and the thicker bezel is on the top of the video wall.
But there is a catch. This will not work when using three rows or more as the middle row obviously cannot be flipped. With all that said, the main reason to make a video wall with TV’s is because they are certainly significantly less expensive than commercial displays. If budget is a constraint for your video wall project, TV’s are a great alternative for your deployment.