Smoothness:
LED display‘s smoothness is between ±1mm which guarantee normal display. Partly bulge and concave will cause the blind spot for the viewing angle.

Brightness and viewing angle:
indoor full color brightness is between 800-2000cd/m2, while outdoor full color brightness is between 5000-7500cd/m2. so that display can operate normally, otherwise images will not be displayed clearly for too bright or too dark. The brightness is decided by LED chips size. Viewing angle size decided the number of audiences, the size of the viewing angle is decided by the chips encapsulation.

White balance:
White balance is one of the most important index. Chromatology proved that when red green and blue rate is 1:4.6:0.16, the pure white will be shown. If there is a little deviation of reality rate the white balance will also show deviation. Pay attention to whether there is a white-blue or white-yellow-green phenomenon.

Color blocks and color difference:
The color blocks means there is clear color difference between adjacent module, which is mainly cause the bad control system, low grey level and low scanning frequency.

Color reducibility:
The color reducibility  means display of color reducibility which require the display color and play source color keep highly consistent which can guarantee the reality of image.

Whether there is mosaic or dead center phenomenon:
Mosaic means display’s color variegation on unit module, which display always bright or dark on small square, i.e. Module necrosis. It mainly because the bad quality of connectors. Dead centre means a single dot always bright or dark which decided by the chip’s quality.

Static screen is corresponding to the scan screen. Static screen is the LED display in the display text, images, video, LED lights on display is lighted at the same time; it is not like the scan screen to use the person eye‘s temporary characteristics,Scan screen instead of using the human eye as the visual characteristics of temporary stay, to light each line of Led screen separately.

As we all know, led display is drived by room ratio, the brightness is related to the light time. So, if the same brightness of Led, the brightness of static screen is more than scan screen. Therefore, a static screen is used for high-brightness  and outdoor display, and scan screen commonly use for scanning screen which do not need the high brightness to save the driver cost.

However, with the LED materials technology is developed continuesly, brightness of LED is improved continuously. In order to save the cost, outdoor display also use scan driver. Of course, the high request for the control and driver when use scan driver for outdoor led display, also request the very high performance chips.

1. Frame Refresh Frequency
The time of picture being displayed in Led display screen gets updated in unit interval. Usually it is 25Hz, 30Hz, 50Hz, 60Hz and so on. The frame frequency is higher, the continuity of the changed frame is better.

2. Refresh Frequency
The time of picture shown in Led display screen gets repeated in each second. Usually it is 60Hz, 120Hz and 240Hz. The refresh frequency is higher; the image on Led display screen is more stable.

3. Viewing Angle
Viewing angle is the maximum angle at which a Led display can be viewed with acceptable visual performance. It includes horizontal and vertical view angles.
When the viewers move to the left side or the right side of the Led display panel, they will see the Led display brightness gets decreased; when the brightness is decreased to the half of the maximum, the viewer’s current position angle plus that in the opposite direction is called Horizontal viewing angle; vertical viewing angle can be measured in the same way.

4. Optimum viewing distance
The optimum viewing distance is a distance where user can see all the content of the Led display screen completely, no color cast, at that place the image is clearest for viewer. The optimum viewing distance = pixel pitch / (0.3~0.8), this is an approx. range. For example, Led display P16mm, the best viewing distance is 20~54 meters.

5. Flatness
The surface of Led display panel is not flat per the criterion that will cause the Led display image distortion. The quality of Led display surface roughness is determined mainly by the production process.

Outdoor LED display, which is made by high brightness LED lamps, also like indoor LED display, can display whatever the format text, graphic, animation, real-time information and anything that can be showed on the computer monitor. The pitch size can be even from 3.91mm, 4.81mm, 5mm, 6mm, 8mm 10mm, 12mm, 16mm, 20mm, 25mm, 31.25mm, etc.

The outdoor LED display function is same as indoor LED display, only the application place is different, one is for indoor which intensity will be lower, and not waterproof, one is for outdoor which intensity will be higher and waterproof.

There are many advantages, such as high bright, long life, work statable, use in wide range, etc., and installed widely in the market, hotel, stadium, airport, transport station, in-tunnel, stock exchange, school etc, to show the notice, advertisement, news, weather and something special information from customer.

We have the easy-use software for the LED display board, which is of windows interface, to edit the display mode of image, video and information at your will. And control the display board freely. At the same time, the brightness of the display board can be controlled by software according to the lighting of site.

In addition, we supply the function of GPRS (Introduction later). Every customer can update the information by the computer which is connected internet.

In one word, the LED display board is the combination of advanced system and modern display. More and more customer will use by its function and convenient control.

Indoor LED display board, which is made by high bright SMD LED or dot matrix LED module, can display whatever the formatted text, graphic, animation, real-time information and anything that can be showed on the computer monitor. This new modern information display product is gathered with the technology of micro-electron, photoelectron, computer, and information disposal. The pitch size can be 2.5mm, 2.9mm, 3mm, 3.91mm, 4mm, 4.81mm, 5mm, 6mm, 7.62mm, 8mm, 10mm,, etc..

The fine pitch LED display, also called UHD (Ultra High Definition) LED Display, is also indoor LED display. With the development of LED technology and active market requirement, fine pitch LED display is getting more used, especialy for high-end video application. Pitches can be pitch 1.2mm, 1.875mm, 1.9mm, 2.0mm, etc.

We usually see the ‘IP rating‘ of Ingress Protection in the LED display product specs, generally it defines the protection degree that LED display products should meet for outdoor or long time use.

LED screens must be able to work 24 hours a day and 7 days a week and withstand extremely bad weather. For manufacturers it is required that the LED screens meet the criterion for outdoor LED screens IP65, and for indoor LED screens IP20. So what do these criterions mean? And what does IP65 and IP20 stand for?

The IP code (or International Protection Rating, sometimes also interpreted as Ingress Protection Rating) consists of the letters IP followed by two digits and an optional letter.

As defined in international standard IEC 60529, it classifies the degrees of protection provided against the intrusion of solid objects (including body parts like hands and fingers), dust, accidental contact, and water in electrical enclosures of the LED display screens. The standard aims to provide users more detailed information than vague marketing terms such as waterproof.

Let‘s take some examples for detailed explanations:

Front Outdoor LED Screens: IP67

The first digit indicates the protection against dust. And "6" means Dust Tight, which means no ingress of dust and complete protection against contact. The second digit indicates the protection against liquids. And "7" means ingress of water in harmful quantity shall not be possible when the enclosure is immersed in water under defined conditions of pressure and time (up to 1 m of submersion).

Back Outdoor LED Screens: IP55

The 2 digits indicate the same parameter with above. But the letters are different. And the first "5" means Dust Protected: Ingress of dust is not entirely prevented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment; complete protection against contact. The second "5" means: Water projected by a nozzle against enclosure from any direction shall have no harmful effects.