What is LED TV Backlights?

LED-backlit LCD television is a liquid crystal display television that uses light-emitting diodes (LEDs) as backlight sources. Some TV manufacturers, such as Samsung, Panasonic, Toshiba, Philips, LG, and Sony, call it LED TV (LED TV), but this does not refer to TVs that use light-emitting diodes as image display. Similarly, LED-backlit liquid crystal displays are referred to as LED Monitor.

With the increasingly fierce competition in the LED TV market and the gradual maturity of LED applications, various TV manufacturers have been actively introducing LED-backlit LCD TVs in an attempt to win the top spot when household TVs are changing.

Types of Light Emitting Diode Backlight Technology

LED backlight technology can be divided into direct back-lit or full LED array back-lit, DLED and edge LED back-lit, ELED, and the LEDs used in the direct type are divided into white LEDs and red and green LEDs. , two blue light-emitting diodes.

Direct type LED backlight technology

The direct-type LED backlight technology is to arrange a plurality of LEDs in an array, put them behind the diffuser and LCD, and directly illuminate the LCD. In this way, the direct type can quickly fine-tune the brightness of the light-emitting diodes according to the luminosity changes of different parts of the screen, greatly improving the dynamic contrast to the level of plasma displays. The disadvantage is that a large number of light-emitting diodes need to be used, which consumes electricity, is thick and has a high price.

Direct LED backlights use white light-emitting diodes and also use red, green, and blue three-color light-emitting diodes (RGB LEDs). Using RGB LEDs can have a wider light spectrum, that is, a wider color gamut.

Side-Illuminated LED Backlight Technology

The side-illuminated LED backlight technology is to place white light-emitting diodes on the four sides of the LCD. There is a reflector of a similar size to the LCD behind the LCD. The LEDs are illuminated from the gap between the LCD and the reflector. The pattern can reflect the light from the LED to the back of the LCD after 90° reflection. These reflectors are fine enough to evenly distribute the light from the LEDs to the back of the LCD without the need for a diffuser.

Compared with RGB LEDs, white light-emitting diodes consume more power. In addition to the loss of reflectors and the LED irradiation angle, the original power consumption of side-illuminated LEDs will be higher, but because there are no diffusers, the loss of diffusers is eliminated. The power consumption of the side-illuminated LED backlight can be achieved at the same level as the direct-illuminated type.

The side-illuminated type can be made thinner and lighter than the direct type, but the color gamut and contrast are not as good as the direct type.

In the past, side-illuminated LED backlights could not quickly adjust the brightness according to the brightness changes in different parts of the screen.

Differences between LED backlights and CCFL backlights

In the past, the light source of the thin film transistor liquid crystal display used a cold cathode fluorescent lamp as the backlight source. The difference between the two lies in:

· Light-emitting diodes can change the intensity of light very quickly, so the backlight brightness can be adjusted locally according to the brightness requirements of the local image, so dark images can be darker, and the dynamic contrast can be much higher than CCFLs. Especially the direct type LED backlight, the improvement of dynamic contrast ratio is more obvious.
· The direct-lit LED backlight using independent three-primary LEDs has a wider color gamut than CCFLs.
· The use of an LED backlight can reduce the thickness, volume, and weight of the TV, and the edge LED can reach less than 1cm.
· The LED backlight itself saves power compared to CCFLs at low and medium luminosity. With the addition of dynamically dimming the LEDs according to the surface image, the LED backlight can save up to 20-50% of power consumption.
· The lifespan of LED backlights is much longer than that of CCFLs.
· LED backlight is more environmentally friendly than cold cathode fluorescent lamps. Light-emitting diode backlights are lighter in weight and consume less fuel in transit. LEDs are more environmentally friendly when disposing of them than CCFLs, which contain trace amounts of mercury. The longer lifespan also reduces waste generation.
· The production cost of LED backlights is high.