Technology

Talk about “high brightness” and “high energy saving” of LED display screen

On how to save energy for LED display, more and more people in the industry have been aware of it from the aspects of highlighting LED lights, driving IC, switching power supply, product power design, intelligent energy saving system design and structural energy saving design. Indeed, how to find the best balance point in these areas can achieve the best LED display energy saving effect.

But I do not know when, do not know what is the reason, perhaps in some manufacturers intentionally or unintentionally, the concept of high energy saving is quietly “high brightness” blurred or even replaced: under the same cost, the higher the brightness of the display, the more “energy saving”, the more value! And gradually become their superior value for money feedback advantage.

In fact, in order to achieve the goal of good energy saving, excessive pursuit of high brightness is contrary to energy conservation. Next, we will analyze the potential relationship between “high brightness” and “high energy saving”.

At present, the most popular 12000cd/m2 high brightness LED lamps in China are large size LED chips. This large size LED chip is widely adopted by most LED display manufacturers as the mainstream of the market. There is no core technology to speak of. As we all know, the brightness of the LED screen is directly proportional to the driving current of the LED lamp. The brightness of 12000cd/m2 is nothing more than increasing the driving current of LED lamps. However, the physical characteristics of LED lamps will be inevitable: high brightness LED lamps will inevitably be accompanied by high attenuation and low stability. High attenuation is not conducive to the long term use of LED display, but also a congenital defect of excessive pursuit of high brightness, and this innate defect will damage the life and picture effect of the LED display in an instant and multiplier effect.

Taking the high brightness PH16mm display as an example, the technical parameters of this high brightness LED lamp show that the brightness of 12000cd/m2 will be seriously attenuated to 8000cd/m2 within 1.5-2 years, and its annual attenuation rate is over 20%. And some irresponsible vendors in the promotion of the announcement of 2 years after the brightness is still more than 10000cd/m2, and consumers bought this screen, 2 years later, even if the attenuation is very fast, but the contract has been completed, the complaint is no door. In fact, consumers can use a very simple way to verify the effect of a few of these high brightness displays that have been running for more than 2 years and used more than 12 hours a day. More seriously, the high working current has not changed after the brightness of the luminance has fallen from 12000cd/m2 to 8000cd/m2, which will increase the speed of its brightness attenuation more, and cause the later attenuation to speed up several times and become a high attenuation display. It also exists in the vicious circle of luminance attenuation, which can not satisfy the requirement of long term use.

In order to avoid light pollution and meet the requirements of environmental regulations, the brightness standards used for LED display are different. As we all know, reducing the brightness will more or less lose the grayscale, the greater the brightness adjustment, the greater the grayscale loss. Therefore, for example, the initial brightness value of the LED screen is set to 12000cd/m2, when the night is lowered to 800cd/m2 brightness, or the gray level is greatly lost, the quality of the night is very poor; or the brightness can not be adjusted to the standard requirements for night use, and the severe light pollution is formed.

As a result, the high value of high brightness in the market is not a technology lead for LED display technology, but a high current and high brightness that has been sacrificed for the life of the display screen. On the contrary, it is hard to avoid being overlooked and awkward.

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