Home » knowledge » LCD Panel

LCD Panel

The LCD Panel is the material that determines the brightness, Contrast, color, and viewing angle of the LCD. The price trend of the LCD Panel directly affects the price of the LCD. The quality of the LCD panel and the quality of the technology are related to the overall performance of the LCD.

Whether the LCD panel can achieve the 16.7M color of true color display, its meaning refers to the ability to physically display 256 levels of gray in the three color channels of R.G.B (red, green and blue). Many factors such as output, pros and cons, and market environment are all related to the quality, price and market trend of the LCD display itself, because about 80% of the cost of an LCD display is concentrated on the panel.

Type introduction
The quality of a Liquid Crystal display must first look at its panel, because the quality of the panel directly affects the viewing effect of the picture, and the LCD TV panel accounts for more than half of the overall cost, which is the main factor affecting the cost of the LCD TV, so To choose a good LCD monitor, you must first choose its panel. The LCD panel can determine the brightness, Contrast, color, viewing angle and other very important parameters of the LCD to a large extent. The development of LCD panels is fast. From the three generations in the previous years, it quickly developed to the fourth and fifth generations, and then skipped the sixth generation to reach the seventh generation, and the updated eighth-generation panel is also being planned. The manufacturers of LCD panels are mainly Samsung, LG-Philips, IVT, AUO, BOE, and Huaxing Optoelectronics. Due to the differences in the technical level of each company, the LCD panels produced are roughly divided into several different types. Common ones are TN panels, VA panels such as MVA and PVA, IPS panels and CPA panels.
TN panel
The full name of TN is Twisted Nematic (twisted nematic) panel. The low production cost makes TN the most widely used entry-level Liquid Crystal panel, and it is widely used in mainstream low-end liquid crystal displays on the market. Most of the TN panels we see are modified TN+film. Film is the compensation film, which is used to make up for the lack of viewing angle of the TN panel. The viewing angle of the improved TN panel reaches 160°. Of course, this is the manufacturer’s contrast The limit value measured in the case of 10:1, in fact, the image has been distorted or even color cast when the contrast drops to 100:1.
As a 6Bit panel, the TN panel can only display 64 colors of red, green, and blue, and the maximum actual color is only 262,144. Through the “dithering” technology, it can obtain more than 16 million colors. It can only display 0 to The three primary colors of 252 grayscale, so the final color display information is 16.2 M colors, instead of the true color 16.7M colors we usually call; it is more difficult to improve the contrast of the TN panel, and the problem directly exposed is the color Thin, poor reduction ability, and unnatural transition.
The advantages of TN panels are that due to the small number of output gray levels, the rapid deflection of liquid crystal molecules, and the easy improvement of response time, TN panels are basically used in liquid crystal products below 8ms on the market. In addition, Samsung has also developed a B-TN (Best-TN) panel, which is actually an improved type of TN panel, mainly in order to balance the contradiction of high-speed response of TN panels that must sacrifice image quality. At the same time, the contrast ratio can reach 700:1, which is close to MVA or early PVA panels. Many panel manufacturers in Taiwan produce TN panels. TN panels are soft screens. A similar water pattern will appear when you lightly swipe with your hands. In addition, look at the screen carefully. It looks like this:
VA panel
VA panel is a panel type with more high-end LCD applications and belongs to a wide viewing angle panel. Compared with TN panels, 8bit panels can provide 16.7M colors and large viewing angles are the capital of this type of panel positioning high-end, but the price is relatively more expensive than TN panels. VA panels can be further divided into MVA panels LED by Fujitsu and PVA panels developed by Samsung. The latter is the inheritance and improvement of the former. The front side (front view) of the VA panel has the highest contrast, but the uniformity of the screen is not good enough, and color drift often occurs. Sharp text is its killer feature, and the black and white contrast is quite high.
Fujitsu’s MVA technology (Multi-domain Vertical Alignment, multi-quadrant vertical alignment technology) can be said to be the earliest wide viewing angle LCD panel technology. This type of panel can provide a larger viewing angle, usually up to 170°. Through technology authorization, panel companies such as Chi Mei Electronics (Qingjing Optoelectronics) and AU Optronics in Taiwan Province of my country have adopted this panel technology. The improved P-MVA panel has a viewing angle of 178° close to the horizontal, and the gray-scale response time can reach 8ms or less

Samsung Samsung Electronics’ PVA (Patterned Vertical Alignment) technology also belongs to the category of VA technology, and it is the successor and developer of MVA technology. Its comprehensive quality has surpassed the latter in an all-round way, and the improved S-PVA can go hand-in-hand with P-MVA, obtaining extremely wide viewing angles and faster and faster response times. PVA uses transparent ITO electrodes to replace the protrusions of the liquid crystal layer in the MVA. The transparent electrodes can obtain a better aperture ratio and minimize the waste of the Backlight. This mode greatly reduces the possibility of “bright spots” on LCD panels, and its status in the LCD TV era is equivalent to the “long tube” in the CRT TV era. Samsung’s PVA mode wide-view technology is widely adopted by Japanese and American manufacturers due to its strong production capacity and stable quality control system. PVA technology is widely used in mid-to-high-end LCD monitors or LCD TVs. VA panels are also soft screens. A similar water pattern will appear when you lightly swipe with your hand. If you look closely at the screen, it looks like this: IPS panel, LCD panel, LCD panel

IPS (In-Plane Switching, plane switching) technology is a liquid crystal panel technology introduced by Hitachi in 2001, commonly known as “Super TFT“. The IPS camp, LED by Hitachi, has gathered a number of manufacturers such as LG-Philips, HannStar, IDTech (a joint venture between Chi Mei Electronics and IBM of Japan), but there are not many models that can be seen in the market. The biggest feature of the IPS panel is that its two electrodes are on the same surface, unlike other liquid crystal mode electrodes, which are arranged on the upper and lower sides in a three-dimensional arrangement. Since the electrodes are on the same plane, the liquid crystal molecules are always parallel to the screen regardless of the state, which will reduce the aperture ratio and reduce the light transmittance. Therefore, the application of IPS to LCD TVs will require more backlights. In addition, there is a S-IPS panel that is an improved type of IPS
The advantages of IPS panels are high viewing angle, fast response speed, accurate color reproduction, and low price. However, the disadvantage is that the light leakage problem is more serious, and the black purity is not enough, which is slightly worse than PVA. Therefore, it is necessary to rely on the compensation of the optical film to achieve a better black. IPS panels are mainly produced by LG-Philips. Compared with other types of panels, the screen of IPS panel is more “hard”, and water pattern deformation is not easy to appear with a light stroke of the hand, so it is also known as a hard screen. When you look at the screen carefully, if you see fish-scale pixels facing left, plus a hard screen, then you can be sure that it is an IPS panel.