Grade A, A-, B, Used Panel Comparison

August 5, 2023

A Batch Of LCD Panels Has A "Grade"

Before making a decision to buy a LCD Display TV product for a B2B Purpose, it is a good idea to understand the most important part, the LCD Panel itself. No matter how a product sourcing manager tries to reduce the unit price of a TV by altering the material of the shell, speaker, mainboard, or even power cable, it would be useless because these parts only impact around 10% of the finalized unit price. On the other hand, the end users, who will use the product for various purposes in various scenarios, will rate display quality as the first factor.
As a result, having a good LCD Panel is the cornerstone of a TV product, and this is why Mianhong, a 12+ years ODM/OEM TV wholesale manufacturer, considers a “Grade A” Panel as the default for its customers.

The LCD Panel Manufacturing Process Is NOT PERFECT

Although there are many LCD Panel Suppliers/factories that have built up advanced production lines, the yield rate of an LCD TV can not reach 100%. It is common to find issues within a batch of LCD panels because the LCD itself is a complicated structure.

A unit of liquid crystal is too small to see by the eyes, so it is hard to perfectly 100% to make sure that each liquid crystal can work. If some liquid crystal molecules fail to work, those pixels will be “dead”.

				
					Response Time(ms):The time it takes for the liquid crystal molecules to twist or recover by applying a voltage within the liquid crystal molecules. The shorter the response time, the user will not have the feeling of tailing when watching dynamic

Defective Pixels

Liquid crystal defection is only one of the reasons why the LCD panel manufacturing process is imperfect. Other issues cause defective pixel dots, too.

Major Types of Defects: These defects will cause function failure, or reduce the product’s usability for its purpose. With major defects, the LCD panel itself can not be any grade since it is failing to display.
Verticle Line: An abnormal line appears in the vertical direction.
Horizontal Line: Abnormal line appears in the horizontal direction.
Crossline: Abnormal cross line appears in the display.
No Display: No signal outputs in the display, on the power-on test.
Irregular Display: Abnormal signal outputs in the display, on the power-on test.

Minor Types of Defects: The defect does not reduce the usability and function. Minor defects will downgrade the panel level from A to A-, as long as the defects meet the minimum number.
Dots Defect: Bright/Dark/Adjacent appear in the display. Points(sub-pixels) on the display are not working properly and usually result from contamination.
Scratch/Dent on Polarizer: Polarizer is damaged on the surface.
Foreign material: Foreign material in the display, sometimes it is visible dust.
Mura: Uniformility appears in the display.
Polarizer bubble: The Polarizer bubble appeared in the display.

Defining Grade A, Grade A-, Used Panel

Again, the LCD panel is not perfect, so the panel industry and manufacturers have defined the level of an LCD panel by counting its “defect dots.” Be aware that different manufacturers make their own standards. Mianhong lists the average level here, based on the suppliers and the internet. It may not be correct because it is the average. Mianhong hopes customers can clearly understand what these defective pixels are and that it is OK to accept that the LCD panel is imperfect. Different grades of panels result in price changes.

Grade	A	A-	B	Used
Bright Dot	<=0	<10	?	?
Dark Dot	<3	<10	?	?
Sum(Bright+Dark)	<5	<10	?	?

Remember: LCD Panel is Not Perfect.

It seems that Grade A+ is the best, as everything is perfect. However, Grade A+ is the most expensive, and it needs to be picked manually from a batch of Grade A panels. Some other factories may call A+ an A to trick customers or probably call S A, which sounds better to convince customers. A- panel may be a commercial choice because the end users cannot detect the defect dots if they are not too far away from the TVs. A- should not be your choice if you are a distributor and perfectionist.

Don't Be Tricked By Used Panel

Used Panel Scams happen every month. Used Panels are recycled from other old used TVs. The Used panels usually come with an extra low price, so some factories can use these used panels to trick customers into placing an order. The used LCD panel for a TV is like placing a simple bandage on a bleeding wound. It may work as expected at the beginning of usage, but it is hard to guarantee the quality after a few months. On the other hand, the used panel is not a “batch” because most of the used panels come from different sources. If you order a container of TVs produced by used panel, then this “batch” TVs get an uneven quality.

				
					For B2B Product Sourcing: If there is an extra low-price TV quotation, be aware of the used panel.

Conclusion

After reading this article, Mianhong ensures that you, with a product-sourcing intention, have a basic idea of a suitable LCD panel. Mianhong will always use the Grade A level panel as default because we want to provide the best display quality worldwide. Be aware of the spamming price that is made up of used(second-hand) panels.

For an A Grade, it it 100% sure that it has 0 bright dots, otherwise it can become A- Grade. For a B Grade, it must have one major type of defect.

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