LED backlight technology classification and comparison

At present, there are three main ways to apply LED backlight technology in the field of LCD TV : direct-type three-primary color RGB- LED light source, direct-type white LED light source and side-type white LED light source. Direct-type RGB-LED light source technology is absolutely the first in comprehensive display advantages, but the price cost is also the highest, and it is not likely to be popularized in the market. LED TVs currently sold on the market generally use direct-type white LED light sources and side-type white LED light sources. Samsung and SONY use side-type white LED technology, while Sharp and Hisense use direct-type white LED technology.

Direct-down type: Emphasis on excellent image quality

Companies that use direct-down LED technology believe that the advantages of direct-down LED technology in picture control are better than those of side-entry LED technology, and that the prices of side-entry LED TVs are inflated. "Compared with the two methods, the 'direct-down' method has a more perfect performance in picture quality." Taking a 55-inch LED TV as an example, the direct-down product evenly distributes more than 3,000 LED lights behind the panel , so that the backlight can be evenly transmitted to the entire screen, and the picture details are more delicate and realistic. The side-entry type, on the other hand, installs more than 400 LED lights on the border of the panel, so that the light source shines from the side. Although this can minimize the thickness, it is easy to reduce the picture brightness in the form of an "X" (that is, the surroundings are brighter than the center) because the number of LED lights is reduced by nearly 7 times.

In addition, direct-type LED TVs also divide the LED backlight into several cells. When displaying black, the light of the corresponding LED area is directly turned off to show a very perfect black. Therefore, companies that use direct-type LED technology believe that direct-type LED backlight can present images more accurately and show excellent color and light-dark contrast effects.

Side-entry type: ultra-thin and energy-saving

"Compared with direct-lit backlight technology, edge-lit backlight technology requires higher overall system design and integration capabilities of the enterprise. In addition, from the perspective of manufacturing cost, the use of edge-lit white LED technology must consider the need to make the entire machine (host power supply , circuit, screen power supply and heat dissipation, etc.) lighter and thinner, which often results in increased costs in many aspects. Therefore, its overall machine cost is higher than that of direct-lit white LED products." Samsung TV technicians gave this explanation for the inflated prices.

The thinner size has become the biggest highlight of edge-type LED TVs. According to the reporter, the thinnest edge-type LED TV on the market is only 2.99cm thick, while the thinnest direct-type LED TV is 5.5cm thick.

Is "thinness" important? Home appliances Industry experts said that consumers care more about the "thinness" of electronic products, because this is an obvious improvement in product quality, and it is the ultimate intuitive embodiment of a brand and enterprise's R&D capabilities and manufacturing technology. Every inch reduction in the product's appearance means an improvement in technology. In addition, edge-type LED TVs are relatively more energy-efficient. Taking a 52-inch LED TV as an example, the power consumption of edge-type LEDs is only 186.5W, while the power consumption of direct-type LEDs is as high as 304W.

Not much difference overall

Whether the direct-down type or the side-entry type is better seems to be an unanswered question.

An LED technology test conducted by the National Radio and Television Product Quality Supervision and Inspection Center gave an interesting answer. "We conducted a comprehensive test and comparison of the brightness, chromaticity parameters and other technical indicators of the same brand of edge-type LED TVs and direct-type LED TVs. From the results, the three parameter indicators of direct-type and edge-type LED TVs are slightly different in terms of picture color performance, brightness uniformity and contrast , but the overall difference is not large." Dr. Wen Na from the whole machine testing room of the National Radio and Television Product Quality Supervision and Inspection Center said.

Regarding the development of LED backlight technology, some industry insiders believe that there is still a long way to go. After all, consumers have just come into contact with the new word "LED" and have not yet understood its true meaning and advantages. "Since the second half of this year, many manufacturers have launched their own brand of LED TVs. LED is the future development direction and will have a bright future. As a consumer, you should calmly treat various comments, not follow the trend, and make your purchase after you have made an accurate decision and have a thorough understanding of the product before purchasing. You will never suffer a loss."

A brief comparison of the advantages and disadvantages of the two technical methods

Advantages Disadvantages

Direct-down type The image quality is more perfect, and the thickness is difficult to be ultra-thin

Side-entry type Ultra-thin thickness, energy-saving The screen brightness decreases in an "X" shape