|Questions and Answers for basic LED screen displays and Signs.|
What’s the factors that effect screen size allowed by the user’s field ?
(1) the connection of effective viewing distance and practical field size?
(2) pixel size and resolution
(3)area estimation based on cell
(4)screen mechanical installation and maintenance operation space
(5)infection of screen obliquity to distance
What’s the displaying effects clients needed ?
(1)characters display: depends on its character size and resolution needs
(2)common video display: 320×240 dot matrix
(3)digital standard DVD display: ≥640×480 dot matrix
(4) full computer video ≥800×600 dot matrix
What’s the environmental brightness requirements to the display ?
Common brightness requirements as below:
(1) indoor: >800CD/M2
(3)outdoor (locate south ,face north) >4000CD/M2
(4)outdoor (locate north ,face south) >8000CD/M2
What’s the brightness requirements of RGB in the white color configuration?
Red, Green, Blue contributes differently in white color quality, the root reason is due to human eyes’ retina. feels different to light that has different wavelength. We got below proportions after mass experiments and inspections for your references:??
Brightness proportion of simple RGB: 3:6:1
Brightness proportion of exact RGB: 3.0:5.9:1.1
Why high level full color display should use pure green tube?
In practical production of LED display, should choose tricolor that has high lighting efficiency and vivid pictures.?
LED lamp, in order to make the area of color triangle as close as possible to color curve in tongue shape in chroma chart in order to meet abundant colors and emit enough brightness, the finial curve in tongue shape is 515nm wavelength light, so, high level LED display choose pure green LED lamp whose wavelength close to 515nm. For example, ?to choose LED lamp which has wavelength 520nm?525nm or 530nm
How to calculate brightness of each lamp under the conditions of definite brightness and pixel density ?
The calculating methods as below: ( for example: 2R,1G, 1B)
Red LED lamp brightness: brightness (CD)/M2÷dots/M2×0.3÷2
Green LED lamp brightness: brightness (CD)/M2÷dots/M2×0.6
Blue LED lamp brightness: brightness (CD)/M2÷dots/M2×0.1
For example: 2500dots/sqm, 2R1G1B, brightness requirement 5000 CD/M2, so:
Red LED lamp brightness: 5000÷2500×0.3÷2=0.3
Green LED lamp brightness: 5000÷2500×0.6÷2=1.2
Blue LED lamp brightness: 5000÷2500×0.1=0.2
Brightness per pixel: 0.3×2+1.2+0.2=2.0 CD
why we choose DVI display connector standard ?
(1)The DVI display connector meets the computer international standard
(2)no need to open cabinet, you can install easily
(3)high memory, display good quality dynamic pictures
(4)strong compatible ability of software and hardware
(5)support all operation system and application software, display neatly and conveniently
(6)Volume-produce, low cost, convenient maintenance
Whether we can use a notebook to control the display or not, why ?
Can’t . the display card of a notebook is inside, can’t realize connection with control system. Now, there is a type of notebook with DVI connector, it can realize notebook control.
What’s the differences between using NICHIA tubes and chinese tubes for full color LED display except prices ?
(1)chips: NICHIA produces chips itself, chinese tubes use USA or Taiwan chips usually.
(2)packaging: NICHIA does packaging itself, there is no manufacturer in China; there are more packaging factory for Chinese tubes?
(3)consistency: difference of chip wavelength is less in the same lot of NICHIA tubes, good consistency; worse consistency in Chinese tubes.
(4)life time: longer life time for NICHIA tubes, serious attenuation for Chinese tubes
What’s the differences between indoor module full color screen and SMD full color screen ?
(1) lighting part: normally, the display module is olivine color for module full color screen, more expensive for pure green module; normally, use pure green chips for SMD full color screen.
(2)display effect : pixels in module full color screen looks wider, lower brightness, easy to cause mosaic phenomenon; better consistency and higher brightness for SMD full color screen.
(3)maintenance: not easy maintenance for module full color, higher cost of replacement of whole module; easy maintenance for SMD full color, cell lamp can be maintained and replaced
Can SMD LED be used in outdoor screen ? Why ?
Can’t . requirements for installation structure of outdoor screen is strict, SMD LED can not adapt to outdoor scurviness environment
High requirements for outdoor screen brightness, at present, SMD LED can’t reach the brightness requirements of outdoor screen
Why the lead time of outdoor screen is longer ?
(1)materials purchase: the purchase term of LED lamps is longer, special imported chips, the lead time takes 4-6 weeks
(2)complicated producing technics : need PCB design, cover making, glue filling, white balance adjust, etc
(3)strict structure requirements: design for cabinet, need to consider windproof, rainproof, lightningproof , etc.
How to help client choose suitable display ?
(1)the needs of displaying content
(2)visible distance,, visual angle confirm
(3) requirements of cabinet resolution
(4)requirements of installation environment
What’s the normal length and width proportion of display?
Drawing screen: subject to displaying content
Video screen: normal 4:3 or approaching 4:3;perfect proportion 16:9
Controlled dots by a set of control system
Communication screen A card: single color, bicolor 1024×64
Communication screen B card:: single color: 896×512? bicolor: 896×256
DVI bicolor screen: 1280×768
DVI? full color screen: 1024×512
What factors should be taken into consideration of screen size design ?
-There is three important factors in designing screen size:
(1)? need of displaying content
(2) conditions of field and space
(3) unit template size (indoor display) or pixel size (outdoor display)
-Should increase drop press and startup facilities for 10KW aboved display
-Communication requirements: communication distance is defined by the length of communication line
-Install communication line should according to the length standard of used communication line suitable for the model of installed display.
The communication wires are not allowed to install in the same wire tube with the electronic wires.
Make sure that the LED display be placed flat, don’t lean to the back.
-Hanging installation must use the adjustable pole for up and down.
-Have to fix the hooking lock for fare the LED screen drop off from the wall before install it onto the wall.
-Standing installation must have the position stable screw.
What are the index on the power consume and the requirements for the power supply OF THE LED screen?
The power consume of the LED screen have the Average power consume and the Maximum power consume. We also called the Average power consume as the Working power consume, it’s the factual power consume when it’s operating normally. The Maximum power consume is the power consume when it’s starting or full lighting and the other extreme situations. The Maximum power consume is the necessary factor to consider when using the AC electricity power supply, the depth of the wire and the switch, too. Generally, the Average power consume is one out of three of the Maximum power consume.
The LED display screen is the big size precision equipment. To operate in security and stability, the AV 220V power supply input port of the LED display screen or the connected computers power supply input port need to connect with the ground.
Noted: computers’ power supply input port also must be connected with the body of the computer.
What are the installation requirements of the LED display screen?
Power supply: the power supply connector must be match for the size of the LED display screen.
220V electricity power supply, live wire, neutral/null wire and the earth wire.
380V electricity power supply, three live wires, neutral/null wire and the earth wire.
The intercept area of the live wire is the same as the null.
The LED display screen above 0.1 million KW must have the lower-voltage equipment.
Communication requirements: the communication distance is decided by the length of the communication wire.
The communication wire must be installed under the length standard of the communication wire of the corresponding LED display screen.
What are the considering factors of the Outdoor LED display screen?
Main questions of outdoor display as below:
(1)display installed in the outdoor, solarization and drench, blow and dust, bad working environment, electrical equipment being wringing and damp will cause short circuit, even fire, cause conk out, even fire, result in loss.
(2)the display may be attacked by the strong electromagnetism made by the thunder and lighting.
(3)The big change of the environment temperatures. The Operating LED display will emit a lot of heating, if the environment temperature is too high, the molectron of the LED screen maybe operating un-normally to damage for its bad giving heating out, finally the LED display system will not operate normally as usual.
(4)The display has a wide range of angle, long viewing distance, big change of the environment light, especially the direct to the sunshine.
With these special requirements, the outdoor LED displays needed:
(1) The parts connecting the body of the LED display with the building must be waterproof and anti-leaking strictly as the display. The display must have the measurements for water giving out. Once leaked, it will be given out smoothly.
(2) The lightning rod should be installed on the LED display or the building. The body and the frame of the display must to keep connecting with the earth, the resistor of the earth wire should under 3 Q , so as to the heavy current from lightning can be discharged in time.
(3) Install the ventilator equipment to lower the temperature, keep the inner cabinet temperature in the range of -10 ~ 40 centigrade degree. The back top of the display must install the rolling electronic fans to give the heating out.
(4) Choose the industrial using IC with the working temperature range of -10 ~ 40 centigrade degree for fear the LED display can not start in the low temperature of the winter.
(5) To be seen form a long distance in the high brightness environment, it must be using the extra high brightness LED lamps.
(6) Choosing the new large angle LED lamps as medium, the LED display will have a larger angle, vivid colors, consistent operation and a long life of more than 100 thousand hours. The medium has a popular package with the hat-edge and square shape in cylinder, sealed by Silicon glue, assembly without metal. Also the display has an unique exterior outface, solid and durable, has the characteristics of anti-dazzle, waterproof, impurity proof, protection from high temperature and short circuit.