CCFL, WLED, RGB LED three backlight advantages and disadvantages

- Feb 18, 2019 -

At present, CCFL, WLED and RGB LEDs are still the three main backlight modes of liquid crystal displays. You can understand these backlight knowledge before purchasing LCD monitors. Since the backlight devices are all inside the display, ordinary consumers cannot directly view them, like WLED. And RGB LED backlit display, the business is said to be the LED screen, in fact, the concept of stealing, the real LED screen should be like the design of the billboard on the Grand Plaza (as shown below), the manufacturers that can miniaturize it at present One, so in the LCD market, you can only find another way, OLED may be a good choice.


The real LED screen should look like this:


led


First, CCFL backlight screen advantages and disadvantages


CCFL's full name is Cold Cathode Fluorescent Lamp, which is filled with inert gas (including some mercury vapor). It has a phosphor layer on the inner wall. It looks like a fluorescent tube. It looks like a neon in the city. The structure installed in the LCD display is as shown below (Note: the actual placement position and direction may be different, including the following LED placement positions are also available in several ways): Before the CCFL, most of the use of EEFL backlight technology backlight, CCFL backlight technology and the following WLEDs are currently very mature technologies, and RGB LEDs are still not too mature. To be exact, the design requirements are higher, so many third-rate manufacturers have difficulty designing good quality RGB LEDs. Backlit display.


CCFL backlight screen advantages:


Low cost, simple manufacturing process and mature technology.


CCFL backlight screen disadvantages:


Short life (fast aging), low luminous efficiency (power consumption), low brightness uniformity, low color purity, poor color gradation, environmental protection, large volume, high driving voltage, and low impact resistance (see the big bulb in the picture) I know that I am definitely not resistant to falling.)

alight led



Second, WLED backlight screen advantages and disadvantages


WLED is called White Light Emitting Diode. White LED is an alternative to CCFL backlight. There is not much improvement in technology. When the display backlight is changed to LED, it will save power (about 20% less than CCFL). The characteristics of the battery), long life and impact resistance, the structure of the backlight module is as follows:


1. Side WLED backlight: The side backlight needs to use the light guide plate (glue) to evenly distribute the LED light to the display screen area, so the concept of light leakage is also generated. When the quality of the light guide film (plate) is not good or the structural layer When there is a problem with the adhesion between the two, the light leakage will be very noticeable.


2, the bottom WLED backlight:

ac cob



The evenly distributed LED module at the bottom is also a design method. The design looks like the process is more complicated than the first one. The entire backlight board needs to consider the soldering and wiring problems. The view of the sky is stable when the device is too dispersed. Sexuality definitely has a negative impact. If the RGB LED is sure to cause a delay in the response of the RGB LED.


WLED backlight screen advantages:


Low driving voltage, long life, small size, light weight, good color gradation, more uniform brightness, more environmental protection and impact resistance.


WLED backlight screen disadvantages:


Brightness and contrast are relative (RGB LED) low.



dc cob

Third, RGB LED backlight screen advantages and disadvantages


Although RGB LEDs look similar to WLEDs, they are more demanding in design. RGB LEDs are still the preferred backlight type for some high-end LCD monitors, so the price is also a matter of course. RGB LEDs use three-tone tones and produce white backlights. In engineering, it is necessary to take into account the color shift caused by voltage and current changes, and also need to consider the problem of complete failure or partial failure of RBG LED, etc. Compared with WLED, its production cost is high and complicated ( The cottage is not counted).


RGB LED backlight screen advantages:


Small size, light weight, higher efficiency, better lumen maintenance, better brightness and contrast.


RGB LED backlight screen disadvantages:


High manufacturing cost, color dispersion, color shift, etc. are problems that cannot be avoided by using RGB LEDs. No matter how the technology develops, the whites of RGB and the white of WLEDs will always be different. In addition, RGB LED backlights also encounter response time issues.