- LED lighting project The LED display the cooling problem analysis
why can be widely used in LED display, my conclusion is the following:
1, extensibility: LCD screen do, the more the higher the production line equipment. And the increase of LED display size, it is very simple, the same as the building blocks. The resolution also convenient according to user needs to complete.
2, full color, light bulbs, neon lights, etc are monochrome, finished combination of RGB trichromatic leds.
3, high reliability, LED is a solid lighting, high reliability, unlike the neon tube, bulb requirements such as the vacuum tube.
4, long life: LED chip theory taking can reach 100000 hours, good practice in more than 30000 hours.
5, environment friendly: LED itself is energy-saving pollution-free products.
the LED is now the biggest problem is that the cooling, LED display is the same. LED display is a big power consumption, proper part of the energy wasted on a fever. Heat leads to the following questions:
1, the wavelength drift: wavelength drift will let color correction present problems, LED at low temperature and high temperature, wavelength drift is larger. Based on the test data, the temperature of every change once, wavelength change 0. 2 - 0. 3nm。
2, output brightness down: each Celsius temperature change leads to a change in output 1% brightness, affected by the most obvious during the red light. From - 180% brightness, 40 degrees to 120 degrees of brightness is less than 50%, that is, the brightness of the red light by nearly two-thirds. Relatively, blue light and green light brightness temperature influence was not so strong, especially the blue light. At higher temperatures would present a problem, the brightness of the different colors of leds announced it is not the same.
3, temperature lead to the LED life spans shorter: on the basis of one of America's laboratory data, junction temperature rising from 63 c to 74 c, the LED life spans decreased from 36000 hours to 16000 hours.
4 result in higher system capital, excessive heat components.
5, laying waste to energy, improve the use of capital.
so heat from where come of? From the power supply to the LED lights, to the LED driver, and then to the adjustable resistance, heat part includes LED lights, LED driver, LED cable. Let's in 5 v power supply, for example:
power supply voltage: 5 v,;
领导:领导G / B Vfwd = 3。 2 v, the LED R Vfwd = 2 v
1, LED power by about 20%, LED fever accounted for 50% of the total heat
2, controller and connecting accounted for 5% of the total calorific value
3, drive pressure drop: 1. 8V( G/B) or 3V( R) The pressure drop, fever accounted for more than 45% of the total heat drive part.
leds heating demand increase LED luminous power, controller and the connecting line of fever is less, little room for improvement. Drive part of heating room for improvement is very big, also let's wait for the improved part. Expansion has LED chip leading enterprise to progress, inventories rising and falling prices