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FAQ



1) What are the definitions of  LED, pixel, and pitch?
A light-emitting diode (LED) is a semiconductor device. You can see it as an electronic device that permits current to flow in one direction. And it illuminates when electricity passes through it.
 
A pixel is a point of light and the smallest element of an LED display. An LED display is manufactured by an array of pixels. Pixels are capable to present letters, graphics, animations and videos.
 
Pitch is a terminology to determine the resolution of the LED display. In LED displays, pitch refers to the distance between the centers of two adjacent pixels, and expresses in millimeters. The smaller the pitch size, the higher picture resolution will be represented because of more pixels per area. On the contrary, the bigger pitch size, because of less pixels, will represent lower picture resolution.
 
2)What is virtual pixel, real pixel for the LED screen?
Real LED pixel is the physical LED pixel; virtual LED pixel is theoretically 4 times higher than real LED pixel. Actually, the real effect of the virtual pixel is not really 4 times better. It is only a much better, but not really can be 4 times better. When you LED display system is more than 640*480pixels, actually you don’t need to use virtual pixel if you plan to use the whole LED display for one advertising contents, but if you plan to divide a big LED screen into small sections for many advertising contents, the virtual pixel is still very necessary and useful for you to achieve much better effect.
 
3)How to measure brightness for the LED video display?
Nit is a unit to measure luminance over a square meter. It is also well-known as meter-lamberts.
NIT = meter-lamberts = candela per square meter (cd/m2)
Why does brightness matter?
At night, generally speaking, LED displays are always readable and working fine.
 
4)What is best viewing distance? How to calculate the best viewing distance of the LED display?
Best viewing distance refers to the distance between the LED Display and its viewers, where the people can see a whole and clear picture of the image on the LED display.
There’s 2 ways to calculate the best viewing distance: one is by the pixel pitch, one is by the diagonal.
 
5)What's the environmental brightness requirements to the LED display ?
Common brightness requirements as below:
(1) Indoor: >800CD/M2
(2) Semi-indoor: >2000CD/M2
(3) Outdoor (locate south, face north) >4000CD/M2
(4) Outdoor (locate north, face south) >8000CD/M2
 
6)What is sender card, receiver card & hub card of the LED display system?
Sender card, receiver card & hub card is the LED panel screen’s control system. Sender card is installed in the controlling PC, is the data sending equipment; receiver card is installed in each cabinet, is the data receiving equipment; hub card is installed together with each receiver card, is the data distribution equipment.
All the above composed the main necessary parts of the control system.
 
7)Introduction of IP and way of testing
Instruction of IP (Conform EN60529/IEC529)
Instruction of protection Level (according to EN60529/IEC529)
Protection level IP54, IP is the mark, number 5 is the first marking number, 4 is the second marking number, the first marking number means the contact protection level, the second mark number means the water proof level, contact protection and anti external force (first number) water-proof level (second number).
First number protection area
Second number protection area
Name description:
1. no protection
2. protect from 50mm diameter and big thing. Diameter is 50mm. No damage from the vertical dropping water
3. protect from 12.5mm diameter and big external thing. Diameter is 12.5mm. No damage from the dropping water for an angle of 15 degree. No damage from the vertical dropping water.
4. protect from 2.55mm diameter and big external thing. Diameter is 2.5mm. No damage from the dropping water with angle 60 degree.
5. Protect from 1.0mm diameter and big external thing. Diameter is 1.0mm. No damage from the dropping water with any angle
6. Anti dust, impossible complete anti dust. But there is no damage to the equipment.
7. Anti dust, with an air compress of 20mpa, no dust can enter the cabinet. Water pull from every angle can not cause any damage.
8. No enter of the detector into the cabinet. Short time water proof when drank in the water.
9. protect long time water drank. Water drank under certain condition. The volume should not exceed a certain quantity which can cause damage.
Technique article:
Water proof test
1. Area
Water proof test should include the second digit from 1 to 8, which protection level is IP x 1 to IP x 8.
2. Experiment content for protection of different level.
(1) IPX1
Method: vertical water dropping experiment.
Experiment equipment: water dropping experiment equipment and its experiment method. Please refer to 2.11.
Sample mounting: put it on the normal position on the rotating sample position (1r/min). The distance between the water dropping place and the sample top should not exceed 200mm.
Experiment condition: dropping volume is 0.5 mm/minute
Lasting time: 10minutes
(2) IPX2
Method: 15degree water dropping experiment
Experiment equipment: water dropping experiment equipment and its experiment method. Please refer to 2.11.
Sample mounting: put one side of a cabinet to be 15 degree vertically. The distance between the water dropping position and sample top should not exceed 200mm. Change one side after finished one side. Totally 4 times.
Test condition: water drop 0.5mm/min
Test time: 4 x 2.5minutes (total 10 minutes)
(3) IPX3
Method: water sprinting experiment
a. Throwing water sprinting experiment.
Test equipment: throwing water spraying experiment equipment (please refer to chapter 2.14 for the drawing and method) Sample mounting: choose tube with proper diameter. Put the sample on radius of the mounting place. Make sure the distance between the sample and the spray head not exceed 200mm. No rotation.
Test condition: over flow rate: each output 0.07L/min. when spray water, from the middle point, with an angle of 60degree. The sample was mounted on the middle of the circle.
Constant water sprinting for 10 minutes
b. Sprinting water experiment
Equipment: manual water sprinting equipment, please refer to the chapter 2.14 in this book.
Sample mounting: the horizontal distance between the top and the hand is 300mm to 500mm.
Experiment condition: must install a board with a balance for weighing, water flow is 10L/minutes
Experiment time: calculated according to the area of the cabinet shell. 1min per sqm (not include the installation area.
(4) IPX4
Method: water pulling test
Thriving water pulling test
Equipment and sample position: same as the 3 above
Experiment condition: same as the condition of 3 IPX3.
The spring area is with a 90 degree angle, then spring to the ample which is mounting in the middle of the circle.
Experiment time: same as the number 3 and a of IPX 3 (10minutes)
(5) IPX5
Method: water spring experiment
Experiment Equipment: diameter of spring tube is 6.3 mm, refer to 2.14 in this book
Experiment condition: distance from the sample to the tube is 2.5-3m the water flow is 12.5L/minute
Experiment time: according to the area of the cabinet shell. 1 min/sqm (not include the installation area) at least 3 min.
(6) IPX6
Method: high intensity water springing experiment
Experiment Equipment: diameter of water tube is 12.5mm, refer to the 2.14 chapter
Experiment: distance from the sample to the tube is 2.5-3m the water flow is 100L/minute
(7) IPX7
Method: short time water drank experiment
Experiment equipment, condition: water tank, distance from the bottom of sample to the surface of the water should be 1m at least.
Experiment time: 30min
(8) IPX8
Method: constant water drank experiment
Experiment equipment, condition and time: negotiable by both sides. Higher demand than IPX7
 
8)How to make a good choice between the flight case and wooden case?
Flight case is usually used for the rental LED display, which makes the transportation more convenient and protect the LED display better.
Wooden case is only for one time using transportation, such as the fixed installation LED display, wooden case is the best way for packing since the low cost and at the same time it can also ensure the safety of the LED display.
If your LED display screen system is for the rental use, please choose the flight case,flight cases are easy to transport.