Introduction of natural light and LED backlight technology for LCD TV

LCD TV how to send natural light

In September 07, TCL launched a natural light LCD TV technology, compared with the traditional LCD TV, fundamentally solve the problem of high energy consumption of flat-panel TV, significantly enhance quality basis, can make over 50% reduction in energy consumption of LCD tv.

According to experts, the current flat-panel TVs per hour power consumption is about 300 watts, assuming that every family to watch TV for about 5 hours a day, the TV is a day of electricity consumption of 1.500 kwh / hour (KWH). A TV consumes 547.5 kwh of electricity at least 365 days a year. And the use of TCL natural light technology, if half of the savings calculated, a TV 365 days a year can save electricity by 273.7 degrees. On this basis, if in accordance with the China Chamber of Commerce predicted by the end of 2007 China's urban residents will be 15 million units of flat-panel TVs to calculate the total annual electricity consumption will reach 4 billion 100 million degrees.

The traditional LCD TV light is linearly polarized, we see it with the naked eye in the nature of natural light are very different, people watching for a long time will cause discomfort; and the vibration direction of circularly polarized light propagation in plane is rotating, it is most close to natural light. Because of this, TCL developed a circularly polarized LCD TV technology, this technology significantly reduces the human long time watch LCD TV after the visual fatigue, previously, TCL commissioned the national flat panel display shows that the test engineering technology research center and a domestic famous University Eye Center, long time to watch TV after ordinary LCD blink frequency is more obvious than watch the former high, but no obvious differences were observed before and after long time watching circularly polarized LCD TV blink frequency. It is proved that circularly polarized light can play a significant role in reducing visual fatigue.

LED backlight technology to make LCD TV longer

With the life and production technology requirements of higher LED backlight gradually introduced into the field of television, television manufacturers have begun to vigorously develop this technology. In this regard, as early as in 2006, many manufacturers began to show its external development of large size LED backlight LCD tv. 2007, Samsung, SONY, Hisense and other TV manufacturers began to launch a large size of the LED backlight LCD tv.

In depth understanding of LED backlight technology, we need to first understand the current backlight technology problems. We know that a liquid crystal is a substance that is found between a liquid and a crystal. The wonderful thing about liquid crystal is that it can change its molecular arrangement by the current, and it can control the amount of light passing through the liquid crystal. But the LCD itself does not emit light, so all of the LCD backlight. At present, LCD backlight is almost CCFL (Cold Cathode Fluorescent Lamps, cold cathode fluorescent lamp).

Because the cold cathode fluorescent lamp is not a plane light source, in order to realize the uniform luminance output of the backlight, the LCD backlight module is also equipped with a plurality of auxiliary devices, such as a diffuser, a light guide plate, a reflecting plate, etc.. Even so, it is still very difficult to obtain a uniform luminance output, such as CRT. Most of the LCD in the display of all white or black screen, the screen edge and center brightness difference is very obvious.

In addition to the complexity of the structure, the brightness of the output uniformity is poor, the use of CCFL as a backlight LCD there is a headache problem - short service life. Most of the CCFL backlight in 2 ~ 3 years after the brightness was significantly decreased (life of 15000 hours to 25000 hours), many LCD (especially the LCD screen of notebook computer) in a few years after the screen will appear yellow, dark phenomenon, this is the use of CCFL attenuation defects for a shorter period the.

In fact, LED (Light Emitting Diode, a light emitting diode) is not cutting-edge technology products, it can be seen everywhere in our daily life: roadside billboards, colorful lights, household appliances colors of mobile phone button backlighting, automotive headlamps etc., using LED as light source.

The core part of LED is composed of P type semiconductor wafer and N type semiconductor, a special conductive layer on the P type semiconductor and N type semiconductor pn junction interface will, it is often said that (PN Junction Transistors). Can the PN junction diffusion on the majority carrier of P type semiconductor and N type semiconductor in the resistance, when applying positive voltage on the PN junction, the current from the anode to the cathode of LED, and the PN in minority carrier and majority carrier compound, the excess energy will be transformed into light and released. LED is based on the principle of electro-optic conversion. According to the different physical properties of semiconductor materials, LED can emit different wavelengths and different colors of light from ultraviolet to infrared.

LED device widely used as indicator lamp

Using LED cross sectional diagram of 1.5mm indicator

Schematic diagram of LED unit construction

What are the benefits of LED as a LCD backlight? First, the volume of the LED backlight will be further reduced by LCD. LED backlight is composed of a large number of grid shaped semiconductor, each lattice has a LED semiconductor, so that the backlight on the successful implementation of the LED light source. The flat light source not only has excellent brightness uniformity, but also does not need a complex optical path design, so that the thickness of the LCD can be made thinner, but also has a higher reliability and stability. The thinner LCD panel means the laptop has better mobility. For example, SONY recently launched VAIO TX pen