LCD and LED dismantling comparison test: where is the price difference

- Apr 10, 2018-

                   

Our PChome computer house has launched applicative comparison testing between LCD and LED technology products (gap comparison at a glance between LCD and LED contrast applications). After reading this article's comparative test, users also learned about LCD and LED now. From the obvious difference in the use of experience, whether it is a static picture but a movie game entertainment, the LED backlighting display's strong color reproduction capabilities and color transitions completely put the traditional CCFL backlight display underfoot. Today, the author will continue to use the two products sent by HKC to conduct dismantling tests and compare the internal materials of the products.




HKC sent two products are LED backlit display T9811L and CCFL backlit LCD S988A, the size is currently the mainstream of 19 inches, the screen ratio is also recognized by the public 16:10, and the price difference of as much as 199 yuan, HKC T9811L is 899 yuan, S988A is 700 yuan. The difference of nearly two hundred yuan may make a friend who doesn't catch a cold on the monitor choose the “enough to use” LCD. However, in fact, this is true? We then look at the following dismantling comparisons.


Comparison of LCD and LED backlight control & signal processing circuits


Relative to the first-line foreign brands of products, the domestic display materials generally poor, in order to save costs, some low-end products can only see a PCB board signal processing circuit and backlight control circuit together. Such products cannot be guaranteed in terms of performance or lifetime.


The dismantling process of the display is troublesome. Many screws also need to remember their respective positions when they are dismantled, and also cause damage to the mold. After we first open the back cover, we look at the overall difference.

Backlight circuit comparison




After reading the above picture, I believe that readers will immediately understand why the LED is thinner. The use of LED backlight technology makes the LCD monitor no longer need to do so much for the backlight control circuit. The smaller and thinner LED backlight control PCB version is directly attached between the back cover and the LCD panel. Looking back at the LCD backlight control circuit, the large regulators and capacitors doubled the volume of the PCB board.




HKC S988A display adopts REALTEK single chip scheme RTD2270, mainly supports 1680*1050 and 1920*1200 resolution, including MCU. The chip is mainly for small screens. The T9811L monitor uses a Raychem RTD2120L single-chip control program, from the performance is not much difference, the size of the PCB version is not much difference, but the RTD2120L cost-effective, this is the HKC T9811L display cost-effective reason one.


LCD and LED panel drive circuit chip comparison


The panel drive control circuit plays a crucial role in the arrangement of the night view molecules in the liquid crystal panel. The integration degree and technology maturity of the drive chip directly affect the final display effect of the liquid crystal display.




After dismantling, we can see that the MST7336C in the MStar series chip is used by the HKC T9811L. This chip has a simpler principle, so its integration and technical implementation are easier and the cost is further controlled. The S988A chose the NQVATEK 0836 chip solution of the previous generation. Although the technology is more mature but the integration is not high, it is not cost-effective.


LCD vs. LED Diffuser & Backlight


At present, most liquid crystal displays use two luminescent tubes or two sets of LED backlight modules. This requires a diffuser to evenly light these light sources on the liquid crystal panel. Therefore, whether the diffuser is sufficient to determine the brightness of the surface of the liquid crystal display is uniform. .




After dismantling, we found that traditional LCDs only use two diffusion sheets, while the T9811L uses three-layer diffusion sheets. The natural brightness uniformity of LED screens is obvious.


Core differences


In the recent PC OEM's in-depth analysis of the LED display technology, we mentioned that the current LED display is not a true LED display. The difference from the traditional LCD is that the backlight source is different. Let's take a look at the famous LED backlight display together. What is the difference between CCFL monitors?




From the above comparison picture, we can see that the HKC T9811L display only uses the above LED backlight module, and the LED devices are arranged on the top of the screen very evenly. The S988A uses the traditional two cold light tubes, so that the energy-saving effect of LED backlight display is naturally powerful.