Cheating your money + ruining your eyes! Whoever buys a wide color gamut TV will regret it

In our lives, color can be said to be the most emotional factor that can arouse people's emotional fluctuations. People will have emotional fluctuations when seeing different colors. However, in addition to the colors we see in our daily lives, most of the rest of the time we get color information on TV. Television has always played an extremely important role in the long history of human beings. From the earliest black and white TVs to large color TVs, the television industry has also undergone fundamental changes after being impacted by colors, and the entire picture output has become vivid.

Is high color gamut just a gimmick?

However, with the continuous upgrading of display technology, TVs are no longer satisfied with simply presenting colors, but are more pursuing the accuracy and richness of colors. Since the end of 2014, high color gamut TVs have relied on new backlight technology assisted by quantum dot materials to allow TV color gamut coverage to reach a higher standard. Therefore, in recent years, high color gamut TVs have become the focus of TV manufacturers' publicity, and even use high color gamut as a gimmick to increase TV prices and attract consumers to buy. So, can expensive TVs that only pursue high color gamut really bring us a more amazing visual experience?
Colors can cause fluctuations in people's emotions

The common understanding of color gamut by ordinary consumers is that the higher the color gamut, the better the color presentation. In fact, this understanding is rather one-sided. Color gamut refers to the range of the number of colors that a display device can express, that is, the range of colors that various screen display devices, printers or printing devices can express. The colors of the visible spectrum in nature constitute the largest color gamut space, but for such a large number of colors, a more intuitive form of expression is needed. Therefore, the CIE International Illumination Association has developed a CIE-xy chromaticity diagram for intuitively expressing color gamut.

CIE chromaticity diagram (the middle triangle is the NTSC color gamut)

In the CIE-xy chromaticity diagram, the color gamut range that various real-world devices can display can be represented by a triangular area formed by connecting three RGB points. The larger the area of ​​the triangle, the larger the color gamut range of the display device. However, this range is too large for display technology, and the colors we display on the screen are much smaller than this. So in 1953, the National Television Standards Association (NTSC) of the United States formulated the NTSC color gamut standard based on the CIE chromaticity diagram, planned a 100% color gamut space, and quantified the size of the color gamut by percentage.

The emergence of quantum dot technology has further improved the color gamut coverage of TVs

In the early days, the color gamut coverage of LCD TVs could only reach 40% to 50% of the NTSC standard. After that, the color gamut coverage of TVs continued to rise. Currently, even the most mainstream LCD TVs can reach about 72% NTSC coverage. In recent years, with the continuous development of wide color gamut technology and quantum dot technology, the NTSC color gamut coverage of TVs has basically reached more than 90%, and some can even reach about 140%. However, is such a high color gamut coverage really as good as the manufacturers claim?

Currently, there are two main types of televisions on the market, namely the common LCD and OLED. Quantum dot televisions are still LCD in nature, because they do not get rid of backlight control. The display principle of OLED is self-luminescence, and after being electrically excited, it can directly display very pure red, green and blue primary colors, so the color gamut coverage can easily achieve a high level. At present, OLED TVs basically have white pixels (WRGB) added to reduce the high color purity of RGB OLED.

Currently, large-size OLEDs have added white pixels

The most effective way to improve the color gamut of LCD is to start with the backlight and improve the purity of the backlight, especially the red, green and blue bands. Currently, the most mainstream method for LCD is to change the type of LED phosphor. The latest inorganic phosphor can make the white light emitted by LED have higher purity in the red, green and blue color bands, and can greatly improve the brightness. High color gamut TVs using the new generation of inorganic phosphors generally have NTSC color gamut values ​​of more than 90%, and both color purity and energy efficiency have been significantly improved.

LCD TVs improve backlight purity by adding phosphors

Quantum dots are currently the most ideal material for improving color gamut. Their luminous purity is higher than both organic molecules and inorganic phosphors. In addition, their stability is comparable to that of inorganic phosphors, but their processing performance is the same as that of organic molecules. Therefore, quantum dots can be said to have taken into account the advantages of both organic and inorganic substances. Quantum dot TVs use pure blue light sources to excite quantum dot crystals on the film, thereby releasing pure red and green light, which are then projected onto the imaging system together with the remaining pure blue light. The light provided is extremely pure, far exceeding the luminescence principle of LED phosphors.

Quantum dots are currently the most ideal luminescent material

In addition to improving the purity of the backlight, the color gamut of a TV can also be improved by increasing the number of primary colors. That is, the filter structure on the LCD panel is changed from the original three colors to four colors, five colors or even more. By increasing the number of primary colors and increasing the combination of colors, more colors can be displayed. However, this technology requires major changes in the panel and color adjustment system, and the technical difficulty and cost are high, so it has not been widely used.

In fact, high color gamut TV can also be called wide color gamut TV. It is defined for the color gamut range of mainstream flat-panel TVs, but there is no strict definition standard. However, as far as current TVs are concerned, a TV with a color gamut coverage of more than 90% of NTSC can be called a high color gamut TV. In fact, the emergence of high color gamut means that the TV can display richer colors, and the vividness of the picture has been significantly improved. Due to the increase in the number of colors, the color transition in the picture appears more natural, effectively avoiding distortion and color blocks. More types of colors make the layering of the picture clearer, thereby showing more details and a more realistic effect.

High color gamut TV makes the color transition of the picture more natural

At the same time, the red, green, blue and other colors displayed by high color gamut TVs will be purer, more vivid, and closer to the real colors of nature. In fact, from the CIE chromaticity diagram, we can see that the red, green, and blue reference colors are distributed on the periphery of the color gamut space, so only when the color gamut range is large enough can it contain purer colors. Ordinary TVs are basically unable to achieve the most realistic restoration of pure colors, while high color gamut TVs can display purer colors.

The red, green, and blue reference colors are all distributed on the periphery of the color gamut space.

Although high color gamut TVs have many advantages, they also bring more problems. As the number of colors increases, the picture becomes more vivid, but the displayed colors are not necessarily accurate. While increasing the number of colors, high color gamut TVs also bring a greater burden to color control. If the color control is not accurate enough, the displayed picture will still be distorted and far from the real color. Increasing the color gamut is certainly a good thing, but color control should be taken into account so that the rich colors can play a real effect.

The prerequisite for improving the color gamut is to have precise control over the color, otherwise it will be counterproductive.

As the largest technology media in China, Zhongguancun Online has tested many TV products. From the TV products I have tested, the higher the color gamut coverage does not mean the stronger the color performance. In the actual test process, many TVs have NTSC color gamut values ​​of more than 100%, or even more than 110%. However, through static and dynamic test observations, it is found that the color accuracy of some products does not meet expectations, and even produces color cast or too bright, which looks very unnatural.

This is why the overall color gamut coverage of mobile phone screens is currently showing a downward trend, because it is difficult to accurately control overly rich colors, and things will turn against each other when they reach their extremes. Therefore, high color gamut TVs also depend on the manufacturer's ability to adjust colors, and their color performance cannot be judged only by color gamut coverage. In the actual testing process, the color gamut coverage of top TV products under joint venture brands is basically maintained between 85% and 95%, and the color adjustment is very accurate. If you are a user who pursues color to the extreme, the high-end products under joint venture brands are still very trustworthy.

As a winner of Toutiao's Qingyun Plan and Baijiahao's Bai+ Plan, the 2019 Baidu Digital Author of the Year, the Baijiahao's Most Popular Author in the Technology Field, the 2019 Sogou Technology and Culture Author, and the 2021 Baijiahao Quarterly Influential Creator, he has won many awards, including the 2013 Sohu Best Industry Media Person, the 2015 China New Media Entrepreneurship Competition Beijing Third Place, the 2015 Guangmang Experience Award, the 2015 China New Media Entrepreneurship Competition Finals Third Place, and the 2018 Baidu Dynamic Annual Powerful Celebrity.