First , the application of backlight module has the advantage of saving electricity
LED is applied to the backlight module as a light source, replacing the traditional cold cathode fluorescent lamp (CCFL), which not only has the advantages of light and power saving, small size, long life, low voltage and fast start-up, but also has the concept of environmental protection. For the notebook computer, depending on the size and size of the processor, the power consumption of the LCD panel is about one-third of the total. Due to the low power consumption of the LED, the current use of the LED backlight NB can be extended by more than 1.5 hours. The thickness of the light guide plate with LED can be reduced from 2mm to 0.6mm (13.3å‹ product), the thickness of the screen can be reduced, and the weight of the whole machine will be reduced. Currently, each CCFL contains about 2mg of mercury, using LED as the LED. Light sources can reduce the use of mercury. If you use RGB three colors to mix white light, you can provide better color saturation, and the color of the TV screen will be more vivid. The LED can be dynamically controlled in the area, and is extinguished in a black area in some areas to improve the contrast between light and dark, and at the same time save power. LEDs react quickly, using RGB tri-color LEDs with fast-reacting liquid crystals, and color Sequential can be used to omit the use of color filters.
LED luminous efficiency is only 20 ~ 40lm / W, not as good as CCLM's 80lm / W, while the cost is too high will be the biggest weakness of LED backlight module. A CCFL and a high-brightness LED are priced at around $1.50, but the number of LEDs used far exceeds that of the CCFL. In addition, LED heat dissipation is not good, and the large-size TV needs to be added with a heat-dissipating substrate, which will be another expense. The decay speed of each LED color is different, and the long-term use will have the problem of uneven color.
LCD upstream and downstream manufacturers have invested in LED factories, the main purpose is not to obtain LED production capacity but to consider technology. Technically, the LED package form, the wavelength of light, and the angle of light output all affect the backlight module. The panel manufacturer and the backlight module factory need to cooperate with LED manufacturers with close relationship to provide special specifications for various experiments and reliability tests. In addition, the panel factory and the backlight module factory have faced the shortage of CCFL. Mastering the material source has become an important issue for the panel factory and the backlight module factory. Investing in the LED factory to prevent the shortage of LED after heavy use, rather than focusing on short-term benefits.
Second, the impact and observation focus
Compared with CCFL, the use of LED as a backlight has the advantages of lightness, environmental protection, power saving, etc., but the cost is the biggest disadvantage. It is expected that the proportion of LED backlight used in notebook computers in 2007 will be less than 8%. In the competitive demand of other application fields, LEDs must be screened. How to replace the LEDs that do not meet the requirements of the backlight module will be the most important problem to be solved; at the same time, the TFT-LCD factory and the backlight module want to lower the price to reduce the cost, and the LED In the case of better gross margins for other applications, it is also crucial to be able to supply large quantities.
In 2006, notebook computer manufacturers only introduced 11.3" and 12.1" LED-backlit notebook computers. Due to the small number of notebook computers under 12.1 inches, LED backlights were regarded as high-end models, and the number of requirements was limited. At the beginning, Apple, Asus, DELL and other calculator manufacturers will gradually launch 13.3 inches, and even larger 15.4 inches using LEDs as backlight products, but still positioned as high-end models, and do not intend to ship in large quantities. If the calculator manufacturer has not changed the positioning of the products using the LED backlight module, it will not help the LED industry.
As for environmental protection, the European Union (European Union) implemented the Restriction of Hazardous Substances in Electrical and Electronic Equipment in July 2006. Although mercury is a regulated project, it is now subject to exclusion clauses. At present, CCFL can still continue to use, and the exclusion clause is not abolished, and it is impossible to forcibly exclude the use of CCFL.
In the field of LCD TVs, the cost of LED backlight modules is currently too high, almost three times that of CCFL backlight modules of the same size, and LCD TVs using LED backlights are more than 30% of the price of the same size models. The CCFL factory also has a wide color gamut fluorescent tube (Wide Color Gamut-CCFL), NTSC can reach more than 92%, and currently the TV signal is only NTSC 82%, the effect of high color saturation is still limited, so SONY, Samsung are The LED backlight module LCD TV has been introduced, but the sales are not good, and the index of the declared technology is more than the actual profit.
At present, LEDs will still be used for small and medium sizes below 10 inches. Notebook computers still need to wait for the calculator manufacturers to introduce mid-range products using LED backlight modules. The market can expand, as for TV, there are still costs, technologies, etc. The problem needs to be resolved. I am afraid that it will be based on high-end products and even technical strength in 2~3 years.
Source: Taiwan Industrial Technology Research Institute