LED backlight display briefly explain why LED will save power

The monitor spent the period when the liquid crystal replaced the flat screen, but the liquid crystal of that period, whether it is the size, power consumption, in fact, not so good, an ordinary 15-inch LCD, power consumption is as high as 30W, although compared to the time of the flat Still low. However, new LED liquid crystals now use more energy-efficient LEDs and are more energy-efficient. Power consumption continues to drop 50% or so, and the LCD can be made thinner. However, what is his working principle?

Display devices, like humans, are undergoing evolution, from convex to flat, to CCFLs to large-size LEDs. Almost as Moore's law, a cycle of innovation will usher in double the performance, 19-inch LED power consumption has dropped to 15W, and the 15-inch flat contrast is simply a world of difference.

The current LED, due to the impact of power consumption, even 26, 27-inch large-size display, can still achieve about 30W power consumption, and this power consumption on the CCFL lamp, it is estimated that already broken hundred (eight tubes), so many lamp life is also a problem, but what is the difference between the two? To understand this difference from the beginning of the principle, in fact, the lamp used in our monitor is close to the principle of the lamp in general households.

CCFL, full name Cold Cathode Fluorescent Lamp cold cathode fluorescent lamp. In a glass tube, an inert gas Ne+Ar gas mixture is sealed, which contains a trace amount of mercury vapor (a few mg), and a fluorescent body is coated on the inner wall of the glass. A high-voltage high-frequency electric field is applied between the two electrodes. The mercury vapor is then When the electric field is excited, an energy-reducing luminescence effect is generated, ultraviolet light having a wavelength of 253.7 nm is emitted, and phosphor atoms of the inner wall are excited by ultraviolet rays to increase their energy levels, and visible light is emitted when the atoms return to the original low energy level. Wavelength is determined by the characteristics of the phosphor material). Due to lower manufacturing costs, high power, high brightness, low energy consumption and other advantages. However, the inert gas is stored for a certain period of time, so after a long period of use, the lamp will yellow or even burn.

However, many things are relative. After the LED came out, all the advantages of CCFL have become shortcomings. Lifespan, performance, and energy consumption have all been exceeded by LEDs. The only advantage is the brightness and cost. From the beginning of 2009 to the current 12 years, LED machine cost and CCFL have been almost (on the LCD) and CCFL lamp, the cost is even lower to the level of one yuan. However, why does LED have such an advantage?

One end of the LED lamp wafer is attached to a support, one end is a negative electrode, and the other end is connected to the positive electrode of the power supply, so that the entire wafer is encapsulated by the epoxy resin. The semiconductor wafer consists of two parts, one is a P-type semiconductor, in which holes are dominant, and the other end is an N-type semiconductor, which is mainly electrons. When the two semiconductors are connected, a PN junction is formed between them. When the current is applied to the wafer through the wire, the electrons are pushed to the P area. In the P area, the electrons recombine with the holes, and then they emit energy in the form of photons. This is the principle of LED light emission. The wavelength of light, which is the color of light, is determined by the material that forms the PN junction.

Without the use of inert gas protection, the service life of the LED is up to 100,000 hours, and there will be no yellowing due to inert gas changes such as CCF1. Due to the boost principle, its voltage efficiency has been improved. In general, LED performance is as high as 90%, which is much higher than that of 40% of CCFL. Therefore, a smaller volume and more energy-saving title are obtained. Similarly, no The need for inert gas protection also increases its useful life.

Summary: The display has experienced two revolutions in recent years. The first time it replaced the LCD with a flat panel, the power consumption has dropped by about 50%, and the second time it occurred on the LED instead of the CCFL. The lower power consumption has led to a large area of ​​LCDs. G2631, even if the area reaches 26 inches, but the power consumption can be controlled at around 30W, but also has a more powerful life and relatively similar costs.