The skill of the bad spot detection method of liquid crystal display

One, LCD panel is the largest cost

As we all know, the cost of the LCD panel itself is the most important part of the liquid crystal display. We take the market mainstream 19-inch widescreen LCD display For example, the latest updated international LCD supply price, 19-inch widescreen TN panel price of 122 U.S. dollars, relative to the 19-inch international LCD terminal price of 205 U.S. dollars, the calculation of the LCD panel accounted for the end price ratio reached nearly 60%.

According to the author understand that the liquid crystal display is not a lot of fakes, because the cost of the LCD panel is fixed, the profit of limited products is obviously not enough to make a lot of fakes appear. Secondly, the fake liquid crystal display is very easy to see, so the fakes are still very few. Most of the fakes on the market are mainly from refurbished products from second-hand markets. The main is the control Panel damaged products for maintenance, while the appearance of renovation. However, in any case refurbished, the bad spot problem in the second-hand display unless the whole panel is replaced, there is no way to remove the bad points.

Typical refurbished flat-panel display

Liquid crystal display itself is a relatively limited service life of products, the purchase of old liquid crystal is very harmful. Therefore, in the liquid crystal display, in fact, it is more important to learn to find out whether there are bright spots and bad spots on the display. The second is a simple flat-panel test.

Don't be a pit! What kinds of "bad" points will appear on the LCD screen

I believe everyone in the purchase of liquid crystal, will make a request to the merchant, is to buy a can "package point", even if a little money also at the expense. If you have a "bad spot" on your LCD screen, it feels like you have peas on your face. Although you know the LCD is a bit, but do you know what the point? Please keep looking down.

LCD panels are composed of a large number of pixel points, they can display black and white color and red, yellow, blue three primary colors. Then we can see the image displayed by the LCD panel by combining the pixel points with different colors. However, a few pixel points on the LCD panel do not produce color changes, regardless of what the LCD screen shows the image, these pixels will always show the same color. These faulty pixel points cannot be repaired and can only be solved by replacing the entire LCD panel.

LCD panel's bad point, bright spot, dark spot

And these fault pixels are usually divided into two categories, where the "dark point" is no matter how the screen image changes can not show the "black spots", and more annoying is the kind as long as the boot will always glow "bright spot."

2.1 Highlights: In the case of black screen, it presents R, G, b three pixel points.

2.2 Dark Dots: In the case of screen, there are not pure R, G, b three pixel color points.

The development of liquid crystal display technology is still unable to fundamentally overcome this shortcoming. Because the LCD panel is made up of two glass panels, the middle interlayer is a crystalline droplet of about 5 microns thick. These crystal droplets are evenly spaced and contained in tiny cells, each consisting of three cells forming a pixel on the screen.

Under the magnifying glass the pixel is square, and a pixel is a point of light. Each luminous point has a separate transistor to control the strength of its current, if the control of the point of the transistor is broken, it will cause the light point will always light or not light. This is the highlight or dark point mentioned above, collectively referred to as "bad point"!

2.3 Bad point: In the case of screen, the point of pure black or in the case of black screen is pure white. This point is always in the same position and always is a pure black or pure white point when switching to red, green, and blue color display modes. In this case, the point of R, G, b three pixel points have been damaged, so called the bad point.

Normally speaking, businessmen will say "no bright spot", if you have a LCD panel with two "dark spots", the business is basically not package. Therefore, if you want to buy the perfect screen, you have to buy before the purchase and the merchant said, you so-called "package point" meaning, is the package "dark point", "bright spot", "bad point" or full package. Normally, businessmen will only say that a single "package No bright spot" or "bag no bad point", we remember to do a good job in advance communication, lest the big Chinese New Year, hurt and good.

OK, here is a simple introduction to some of the rapid detection of liquid crystal display has no bad points, highlights and dark points of the method bar