9 Tips for Judging the Merit of LED Screens
9 Tips for Judging the Merit of LED Screens
In order to quickly determine the quality of LED display good or bad, from the point of view of all parties synthesized LED display the following 9 important items. The first 8 items apply to general LED display, the 9th item for small pitch LED display.
For outdoor LED display according to the use of the environment, the maximum brightness will have different requirements, because in the environment of strong light occasions, it is required to led display brightness to be higher, in order to allow the masses to see clearly the content displayed on the screen. In general, the display sits south to north on the maximum brightness requirements of some low, as long as to reach 4000CD/m2 can meet the requirements, while sitting north to south of the display requires the whole screen brightness can reach 7000CD/m2, towards the east and west and south of the requirements are the same, because there will be a part of the time the sun will be directly irradiated to the LED display. Theoretically, the brightness requirement is greater than 5500CD square meter brightness is enough.
High refresh can improve the brightness of the display and color fidelity. With a digital camera can be detected, if it is a high refresh, the picture taken by the camera is very clear, no snowflake points and scan lines. This indicator is especially important when renting screens and televising.
First: the whole screen hits white, the screen should be pure white, without any other miscellaneous colors. If you think there is a little reddish or bluish, it proves that the display materials and process quality control and other problems. After a long time of use, it will become more and more serious.
Second: playing red, green, blue monochrome, the center wavelength of the color is usually what we say is blue and red and green, if a little deeper or lighter colors, proving that the wavelength is off. If a certain color is inconsistent, proved to be too large wave difference, high-quality display in the range of the center wavelength, blue and green wave difference control in 3nm, red wave difference is less than 5nm.
For outdoor LED advertising display generally use elliptic light-emitting tube or patch light-emitting tube, elliptic light-emitting tube has a small angle, brightness and high characteristics, and patch light-emitting tube of the vertical angle of view to be much larger than the elliptic tube, but its brightness to be smaller than the elliptic light-emitting tube, from the user's point of view, should be based on the LED display of the audience surface and the surrounding light environment to select a different angle of view of the light-emitting tube.
For indoor LED display because of its low brightness requirements, the audience is generally wider, so the SMD tube is the best choice. It should be noted that, now part of the market light-emitting tube manufacturers to reduce costs, confuse the user, the brightness of the light-emitting tube to do a relatively high, and the angle of view than the conventional light-emitting tube to do a small angle of view, which will lead to the front of the LED display screen look at the brightness is very high, but the side of the larger angle to watch the image appears to see the situation.
Small size LED chip in order to improve the brightness, usually using a small angle package. Large size does not need small angle package, because it does not need so high brightness. Therefore, large angle (110) high brightness and low current is the best.
1, the material requirements: PCB board thickness, generally use 1.6mm thickness; Material: FR-4 glass fiber board, some manufacturers may use FR-2 paper substrate in order to reduce costs; copper foil thickness: the thickness of the copper foil on the PCB board heat dissipation and the stability of the line has a role that can not be ignored, the normal thickness of the copper foil is 35um (1Oz), while some manufacturers will use 18um (0.5Oz) thickness of copper foil to substandard; then as a consumer how to identify it? You can take an empty PCB through the weight to distinguish, under normal circumstances, the heavier the better.
2, a few key points in terms of design: connectors, connectors are modules and modules between the connectors, the market is now used more than the main two kinds, one is the bullhorn, a row of pins. The advantage of the bullhorn is that through the two card position can be stuck in the row of wires, is not easy to appear due to the failure caused by the problem of connectors; about the choice of electrolytic capacitors and tantalum capacitors, for the requirement of long life of the occasion, tantalum capacitors is undoubtedly the first choice for the requirement of the occasion of the low cost of electrolytic capacitors is the preferred choice.
Method is very simple: look at the number of power supply behind the box, multiplied by the maximum power of each power supply, according to the size of the box can calculate the maximum power consumption of the square meter, the general use of power supply there are two kinds of power supply, 200W and 300W power supply.
Low brightness and high gray will be one of the key factors to distinguish the quality of small pitch LED display products. For small spacing products, the LED display will no longer be compared to who has high brightness, but rather compared to who has low brightness. Than whose display can do to reduce the brightness at the same time without loss of gray scale and picture quality. That is to say, only to achieve a low brightness and high gray small spacing led display is in line with user requirements, with competitive strength of the good products.
The human eye in the indoor dark environment, close distance, long time to watch the high brightness of the small spacing LED display, LED unique high brightness will often make people feel blinding, and even cause eye pain, tearing and vision reduction. Therefore, LED display brightness is too high, will bring visual fatigue to the user of indoor applications, and even serious may cause irreparable damage to the human eye! It can be said that small pitch LED display brightness is absolutely not the higher the better, it must be brought down. A large number of tests show that the brightness of the LED display is controlled in the range of 100 cd/O-300 cd/O this brightness range, the human eye is more comfortable.
But not directly adjust the brightness of the display can solve this problem. Because, the conventional LED display has the characteristics of low brightness and low gray, that is to say, the brightness of the display will be reduced at the same time accompanied by the loss of gray scale of the screen.
- Maximum brightness
For outdoor LED display according to the use of the environment, the maximum brightness will have different requirements, because in the environment of strong light occasions, it is required to led display brightness to be higher, in order to allow the masses to see clearly the content displayed on the screen. In general, the display sits south to north on the maximum brightness requirements of some low, as long as to reach 4000CD/m2 can meet the requirements, while sitting north to south of the display requires the whole screen brightness can reach 7000CD/m2, towards the east and west and south of the requirements are the same, because there will be a part of the time the sun will be directly irradiated to the LED display. Theoretically, the brightness requirement is greater than 5500CD square meter brightness is enough.
- Color temperature
- Refresh rate
High refresh can improve the brightness of the display and color fidelity. With a digital camera can be detected, if it is a high refresh, the picture taken by the camera is very clear, no snowflake points and scan lines. This indicator is especially important when renting screens and televising.
- Wavelength
First: the whole screen hits white, the screen should be pure white, without any other miscellaneous colors. If you think there is a little reddish or bluish, it proves that the display materials and process quality control and other problems. After a long time of use, it will become more and more serious.
Second: playing red, green, blue monochrome, the center wavelength of the color is usually what we say is blue and red and green, if a little deeper or lighter colors, proving that the wavelength is off. If a certain color is inconsistent, proved to be too large wave difference, high-quality display in the range of the center wavelength, blue and green wave difference control in 3nm, red wave difference is less than 5nm.
- Viewing angle of light-emitting diode
For outdoor LED advertising display generally use elliptic light-emitting tube or patch light-emitting tube, elliptic light-emitting tube has a small angle, brightness and high characteristics, and patch light-emitting tube of the vertical angle of view to be much larger than the elliptic tube, but its brightness to be smaller than the elliptic light-emitting tube, from the user's point of view, should be based on the LED display of the audience surface and the surrounding light environment to select a different angle of view of the light-emitting tube.
For indoor LED display because of its low brightness requirements, the audience is generally wider, so the SMD tube is the best choice. It should be noted that, now part of the market light-emitting tube manufacturers to reduce costs, confuse the user, the brightness of the light-emitting tube to do a relatively high, and the angle of view than the conventional light-emitting tube to do a small angle of view, which will lead to the front of the LED display screen look at the brightness is very high, but the side of the larger angle to watch the image appears to see the situation.
Small size LED chip in order to improve the brightness, usually using a small angle package. Large size does not need small angle package, because it does not need so high brightness. Therefore, large angle (110) high brightness and low current is the best.
- Circuit design part
1, the material requirements: PCB board thickness, generally use 1.6mm thickness; Material: FR-4 glass fiber board, some manufacturers may use FR-2 paper substrate in order to reduce costs; copper foil thickness: the thickness of the copper foil on the PCB board heat dissipation and the stability of the line has a role that can not be ignored, the normal thickness of the copper foil is 35um (1Oz), while some manufacturers will use 18um (0.5Oz) thickness of copper foil to substandard; then as a consumer how to identify it? You can take an empty PCB through the weight to distinguish, under normal circumstances, the heavier the better.
2, a few key points in terms of design: connectors, connectors are modules and modules between the connectors, the market is now used more than the main two kinds, one is the bullhorn, a row of pins. The advantage of the bullhorn is that through the two card position can be stuck in the row of wires, is not easy to appear due to the failure caused by the problem of connectors; about the choice of electrolytic capacitors and tantalum capacitors, for the requirement of long life of the occasion, tantalum capacitors is undoubtedly the first choice for the requirement of the occasion of the low cost of electrolytic capacitors is the preferred choice.
- Automated production equipment
- Average power consumption
Method is very simple: look at the number of power supply behind the box, multiplied by the maximum power of each power supply, according to the size of the box can calculate the maximum power consumption of the square meter, the general use of power supply there are two kinds of power supply, 200W and 300W power supply.
- Indoor small pitch: low brightness and high gray
Low brightness and high gray will be one of the key factors to distinguish the quality of small pitch LED display products. For small spacing products, the LED display will no longer be compared to who has high brightness, but rather compared to who has low brightness. Than whose display can do to reduce the brightness at the same time without loss of gray scale and picture quality. That is to say, only to achieve a low brightness and high gray small spacing led display is in line with user requirements, with competitive strength of the good products.
The human eye in the indoor dark environment, close distance, long time to watch the high brightness of the small spacing LED display, LED unique high brightness will often make people feel blinding, and even cause eye pain, tearing and vision reduction. Therefore, LED display brightness is too high, will bring visual fatigue to the user of indoor applications, and even serious may cause irreparable damage to the human eye! It can be said that small pitch LED display brightness is absolutely not the higher the better, it must be brought down. A large number of tests show that the brightness of the LED display is controlled in the range of 100 cd/O-300 cd/O this brightness range, the human eye is more comfortable.
But not directly adjust the brightness of the display can solve this problem. Because, the conventional LED display has the characteristics of low brightness and low gray, that is to say, the brightness of the display will be reduced at the same time accompanied by the loss of gray scale of the screen.