Display quality dominant large size LED backlight gradual industrialization

At present, the cold cathode fluorescent lamp (CCFL), as the main backlight source of LCD TV, has some obvious disadvantages, such as low color gamut, mercury content, low luminous efficiency and so on. The LED (light-emitting diode) with its high color gamut, high luminous efficiency, fast response time, environmental protection and other characteristics, has an important impact on the LCD TV backlight field.

2004, SONY took the lead in the LED backlight technology products, introduced the use of LED backlight 23 inch LCD (LCD) display and a 40 inch, 46 inch LCD tv. Although these products are high power consumption, high calorific value and high prices, but the advantages of LED in the display quality has been fully reflected. SONY in the 2006 International Consumer Electronics Show CES on the public display of its 82 inch LCD TV prototype, using the backlight are LED rather than traditional CCFL. In 2007, SONY unveiled and launched a 70 inch LCD TV with LED backlight technology, Samsung also launched a global market for a 70 inch LED LCD tv.

In the country, in July 2008 Hisense independent research and development of 42 inch ultra-thin LCD TV TLM42T08GP LED market, becoming the world's third companies to achieve LED backlight TV batch.

LCD TV with LED as backlight source is gradually coming into people's sight, and it is gradually industrialized. As a new kind of backlight for LCD TV, LED has a promising future.

Straight down and side guide light currently has advantages

At present, the two mainstream LED backlight architecture is direct and side light guide. In addition, there is an attempt to combine the characteristics of the two types of hybrid, one side of the light guide small units into the entire backlight module, which has the characteristics of both direct and lateral light guide.

Comparison of three methods, we can find the direct type in energy saving, quality (by contrast, regional control, to achieve the scanning backlight) has obvious advantages and so on, but it is difficult to realize ultra-thin design; and the side of the light guide in the ultra-thin design is relatively easy to implement, but the quality and energy saving performance some poor; as for the mixed type, although the performance of energy saving, quality and direct type, but the solution structure, complex process and each unit between the luminance and color uniformity of the problem is a great challenge.

There is a point of view: the LED backlight on the side of the light guide will replace all the other ways to occupy the absolute dominant position, as it can be done very thin. This view is one-sided. LED backlight must be the development trend of energy saving, quality, aesthetics, environmental protection, unity, and not just frivolous. From the whole structure of industrial design to achieve differentiation requires a certain space to play, and the optimal heat dissipation and structural strength design requirements analysis, LED backlight TV machine is ideal in the thickness of 30 mm -40 mm. The straight down as long as the technology effectively overcome the contradiction between the distance between the light and ultra-thin design can achieve this thickness requirements.

Therefore, the analysis of direct type LED backlight light guide side, between the CCFL and the evolution of competition, we believe that the following will present trends: the first is the direct type to occupy the high-end LED, and the side of the light guide to occupy the low-end LED, then gradually replace the CCFL side of the light guide and direct type backlight, and gradually replace the side guide light.

LED backlight technology continues to move forward

With the continuous improvement of the technology and performance of LED devices, the research and development of LED backlight technology for TV applications at home and abroad has also been carried out in an all-round way.

LED work for low voltage devices, low voltage start; the working current of easy control, good operability; solid state light source, good shock resistance, long service life; a wide gamut of around 100%NTSC; do not contain mercury and other harmful substances in environmental protection; fast response, the response speed is far higher than the response speed of the liquid crystal molecules. Therefore, LED is an ideal light emitting device as a backlight. With the continuous development of LED technology, the luminous efficiency of LED will be further improved, and the problem of heat dissipation will be greatly improved.

LED backlight technology can be classified according to the classification, such as back light source optical architecture, LED backlight technology can be divided into direct type, side of the light guide (splicing) and mixed type; species by using LED chip to divide, and can be divided into monochrome (including blue chip + yellow phosphor powder, red green blue chip + dual color fluorescent powder), several two-color and three color; if considering the factors of the liquid crystal panel, the LCD panel can filter, sequential color superposition dimming method etc..

In addition, the dynamic control technology of the LED backlight, the same hardware architecture, because of its light modulation mechanism is completely different, the completion of the function and the realization of the effect is also different. If only from the LED backlight technology considerations, LED backlight technology can be completed by the general function can be divided into: to improve the dynamic contrast, reduce the phenomenon of the tail of the LCD display, energy saving, improve quality, etc.. So the design of a LED backlight LCD TV system should be LED backlight technology can complete the function and hardware architecture required (refer to the LED backlight driving array) into consideration, LED backlight arrangement, partition number, partition array can achieve great display effect and energy-saving performance impact on LED backlight LCD tv.

On the development trend of LED LCD TV, LED technology innovation is an important aspect of promoting its development, higher luminous efficiency, better heat dissipation of LED device development is the trend.

One of the keys to the development of LED LCD TV is the development of LED backlight control technology. The development goal of the LED backlight control function is becoming clearer