With the continuous improvement of consumers' requirements for environmental protection, ultra-thin and high image quality, LED TV, with its absolute advantages in energy saving, environmental protection and color performance, has become a new trend in the development of flat panel in 2009. Today, 360 common sense network will introduce led in detail for you, so that you can be a smart consumer and save your right to know.
There are many kinds of LED. Not all led backlit TVs are perfect picture quality performance. According to color, LED light source is divided into monochrome, double primary color and three primary colors (true color). Of course, with the increase of the number of colors, the improvement of image quality and the performance of color gamut will be different, and the cost will be greater. This can also explain why they are all LED backlight products. Some products are easily 40000 or 50000, while others are only 10000 or 20000. Some manufacturers also use consumers' immature understanding of LED technology to publicize the selling points of their products. However, consumers' right to know has been violated.
LED display classification
First of all, let's take a look at what kinds of LED displays are divided into? What are their characteristics.
Divided into indoor, outdoor and semi outdoor according to the use environment
室内屏面积一般在十几平米以下 ,点密度较高，在非阳光直射或灯光照明环境使用，观看距离在几米以外，屏体不具备密封防水能力。室外屏面积一般从几平米到几十甚至上百平米，点密度较稀 (多为1000-4000点每平米),发光亮度在3000-6000cd/平米(朝向不同，亮度要求不同 )，可在阳光直射条件下使用，观看距离在几十米以外，屏体具有良好的防风抗雨及防雷能力。半室外屏介于室外及室内两者之间,具有较高的发光亮度,可在非阳光直射室外下使用，屏体有一定的密封，一般在屋檐下或橱窗内。
The indoor screen area is generally less than 10 square meters, with high point density. It is used in non direct sunlight or lighting environment. The viewing distance is several meters away, and the screen body does not have the ability of sealing and waterproof. The outdoor screen area generally ranges from a few square meters to dozens or even hundreds of square meters, the point density is relatively thin (mostly 1000-4000 points per square meter), the luminous brightness is 3000-6000 CD / square meters (different orientation, different brightness requirements), and it can be used under the condition of direct sunlight. The viewing distance is tens of meters away, and the screen body has good wind and rain resistance and lightning protection ability. Half of the outdoor screen is between the outdoor and indoor, with high luminous brightness, which can be used in the non direct sunlight outdoor. The screen body has a certain seal, generally under the eaves or in the window.
According to the color, it can be divided into single color, double base color and three base colors
Monochrome refers to the light-emitting material with only one color on the display screen, most of which are single red. It can also be used in some special occasions (such as funeral parlour).
The dual primary color screen is generally composed of red and yellow green luminescent materials.
三基色屏分为全彩色 (full color),由红色，黄绿色(波长570nm)，蓝色构成及真彩色(nature color),由红色，纯绿色(波长525nm),蓝色构成。而目前，索尼的X4500、夏普的XS1A、三星的9系列所采用的RGB—LED背光源就是属于三基色LED背光源。相比单色LED，RGB-LED通过红、绿、蓝三色LED背光灯扩大色域表现范围，同时将屏幕漏光控制在较低限度，提供丰富的黑色表现力，有效地降低能耗。
The three primary color screens are divided into full color, consisting of red, yellow green (wavelength 570nm), blue and natural color, red, pure green (wavelength 525nm), and blue. At present, the RGB LED backlight used by Sony's x4500, sharp's xs1a and Samsung's 9 series belongs to the three primary color LED backlight. Compared with monochromatic LED, rgb-led enlarges the color gamut performance range through red, green and blue LED backlights, and at the same time controls the screen light leakage at a lower limit, providing rich black performance and effectively reducing energy consumption.
Long life advantage of LED backlight
LED, after its birth in 1960s, has been recognized as the terminator of fluorescent tubes, light bulbs and other lighting equipment. LED lamp is also called led. Compared with other light sources, the power consumption of a single LED lamp is the smallest. From blue to red, there are many colors for LED lights, and one special color is white. We customize it as "cold white" and "warm white". In all kinds of colors, there is a problem of color deviation, among which blue and white are more obvious, especially white. Now led suppliers are unable to effectively control them.
LED light source is composed of many grid like semiconductors, each "lattice" has an LED semiconductor, so the LED backlight successfully realizes the planarization of the light source. The flat light source not only has excellent brightness uniformity, but also does not need complex optical path design, so that the thickness of LCD can be thinner, and also has higher reliability and stability.
Secondly, in terms of light-emitting life, LED backlight technology surpasses CCFL, which is the improvement of CCFL technology. The life span of common CCFL backlight is about 30000-40000 hours, and that of some top CCFL backlights (wcg-ccfl) is about 60000 hours. This life span can be maintained for several years even for frequent users. And the life of LED backlight is longer. At present, the life of white LED backlight has reached 100000 hours. Even if it is used continuously for 24 hours, its life can be enough for 5 years.
Outstanding energy conservation and environmental protection, real Green TV
An important factor in the rise of LED backlight and end illumination is the RoHS directive implemented by the European Union. The Directive provides for the elimination of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls and polybrominated diphenyl ethers in electronic devices sold in EU Member States as of July 1, 2006. Mercury is the main component of CCFL and other types of fluorescent lighting. LED lights don't use mercury at all.
In terms of power consumption, compared with ordinary CRT TV, flat panel TV consumes a lot of power, and many consumers are concerned about the energy consumption of TV. It is understood that 12 million flat-panel TVs sold in 2008, if each TV works 4 hours a day, it will consume 2.4 billion kilowatt hours of electricity every year, equivalent to the total annual power generation of several large thermal power plants.
The brightness of LED can be adjusted with the brightness of the screen, which can save more than 30% energy compared with LCD TV. In this way, when displaying the images of some dark scenes, you only need to adjust the local light of the necessary backlight area (the black or dark part on the screen), which can show you the high-quality image effect of natural contrast between light and dark.
Is led better than CCFL at present?
At present, although the traditional CCFL cold cathode fluorescent lamp consumes a large amount of electricity and has a general luminous quality, its luminous efficiency can reach 50-100 lumens / watt, while the luminous efficiency of white LED is only 20 LM / W or even lower at the beginning. However, the luminous efficiency of white LED is increased by 60% every year. So far, the luminous efficiency of white LED devices has exceeded 50lm / W and reached the practical level.
While rgb-led technology, although has many advantages, there are still some inevitable limitations. For example, due to the use of a large number of independent LED devices, the lattice arrangement is quite dense, not only it is difficult to ensure the consistency of each device, but also the heat dissipation is not ideal, and can not reach the ultra long life. Secondly, the luminous efficiency of rgb-led backlight source is slightly weaker. At present, it is generally around 50 lumens / W, and the highest is only 70 lumens / W. to achieve the same level of luminous brightness as ccfl100 lumens / W, it will inevitably lead to the increase of power consumption and heat generation. Secondly, although rgb-led color purity is high, but after long-term use of each LED color attenuation amplitude is not the same, which will also have a greater impact on the picture quality.