I was deceived for 20 years! TV contrast is actually meaningless

Generally speaking, the contrast of a TV is a very important technical parameter. Most TV manufacturers will mark the contrast of their products when selling TVs, and consumers who are a little more knowledgeable will also use contrast as a core indicator when purchasing TVs. Unfortunately, contrast, the most core parameter, actually has no actual reference value in the entire TV market, and this parameter may even be removed in the future.

What is the definition of contrast?

Simply put, contrast refers to the measurement of different brightness levels between the brightest white and the darkest black in the light and dark areas of an image. The larger the difference range, the higher the contrast, and the smaller the difference range, the smaller the contrast value. Friends who have read ZOL TV reviews must know that when calculating contrast, we will play a pure white image and a pure black image on the TV in a dark room, measure the brightness separately, and finally use white brightness/black brightness to calculate the static contrast.

Usually the contrast ratio is calculated by white brightness/black brightness.

From a visual perspective, the greater the contrast, the clearer and more eye-catching the image will be, and the colors will be more vivid. On the contrary, the smaller the contrast, the grayer the image will be, and the color loss will be serious. In fact, the impact of contrast on dynamic video display is much greater than that on static. Since the light and dark transitions in dynamic images are very fast, the higher the contrast, the easier it is for the human eye to distinguish such a transition process.

The improvement in contrast will also bring richer colors

Although there are many ways to measure contrast, there is still no fair and effective standard to measure this data. Some manufacturers use the center brightness method to measure; some manufacturers divide the screen into nine points, then measure the brightness separately and finally get the average value. So strictly speaking, no product's contrast value is absolutely accurate, it is just for reference. With the birth of new technologies, contrast will no longer be used as a reference standard.

OLED? Sorry, infinite contrast

The most talked about topic in the industry is that OLED will replace LCD. Indeed, OLED (Organic Light-Emitting Diode) has many physical advantages that LCD cannot match. Self-luminescence, true color, zero delay, infinite contrast, extreme ultra-thinness, and flexible display are all features of OLED. Currently, both large-size TVs and small-size mobile phones are transforming to OLED technology.

OLED TVs have infinite contrast

Due to the self-luminous characteristics of OLED, when the screen is showing black, the pixels are completely non-luminous, and the black appears deeper. According to the contrast formula, white field brightness/black field brightness, the contrast of OLED screen can reach infinity. In the future, after OLED TVs are widely popularized, we will no longer see the screen parameter of contrast.

QLED will also be self-luminous in the future

Quantum dots are also an innovative display technology, but the current quantum dot technology is still developed on the basis of liquid crystal, and still needs the support of backlight, and remains at the stage of "photoluminescence". The ultimate goal of quantum dot development in the future is to achieve "electroluminescence", which is what we often call QLED. QLED technology, like OLED, can also achieve self-luminescence and infinite contrast.

The ultimate goal of QLED is also to achieve self-luminescence

OLED and QLED are basically the same in panel structure, except for the light-emitting materials (OLED is an organic light-emitting layer, QLED is a QD light-emitting layer). The rest is completely the same from cathode to packaging. Although QLED is still in the research and development stage, it is undeniable that QLED is the ultimate direction of quantum dots. This is why we said before that the contrast of TVs will no longer be a reference standard in the future. In addition to OLED and QLED, the contrast parameters of LCD TVs are also meaningless.

Dynamic contrast ratio is worthless

When we buy LCD TVs, we often see manufacturers claiming that the contrast ratio can reach hundreds of thousands to one, or even millions to one. This is usually the dynamic contrast ratio parameter. It should be noted that dynamic contrast ratio and true contrast ratio are two completely different concepts. The dynamic contrast ratio of the same LCD TV is generally 5 to 10 times the actual contrast ratio. Therefore, dynamic contrast ratio is just a means of manufacturer promotion and has no real practical significance.

Without dynamic contrast, light leakage on LCD TVs will be very serious

To effectively control the light leakage of TV, the easiest way is to add dynamic contrast. The principle of dynamic contrast is to control the backlight current. When presenting a bright picture, the backlight current will be increased to make the whole picture brighter. When presenting a darker picture, the backlight current will be reduced to reduce the brightness to a lower level, thereby obtaining a larger contrast value. At present, the dynamic contrast function of many TV products is turned on by default. Even if it is turned off, at least half of the effect will be retained, so in this case, it is impossible for us to get the true contrast value.

Dynamic area backlight adjustment affects contrast

Dynamic backlight technology is usually found on high-end TV products. Its principle is to divide the backlight of LCD TV into several areas and control them separately. Usually, high-end TVs will divide the backlight areas into six, nine or more. Here we have to mention Sony's dynamic backlight master technology, which can control each LED light source on and off separately. In theory, there are as many backlight zones as there are LED light sources. The complexity of the technology can be imagined.

Dynamic zone backlighting allows for different contrast values ​​on screen

The addition of dynamic backlight also makes contrast less and less meaningful, because the addition of this backlight technology will cause the entire screen to present different contrast values. Since the highest and lowest brightness of each backlight area is different, different contrast values ​​will appear in different areas of the screen, and there will be no unified highest and lowest brightness standards like dynamic contrast, so there is no way to talk about the real contrast value.

In conclusion:

This article analyzes from multiple angles that the parameter of contrast is no longer of great reference value. There is no absolutely reasonable value for the parameter of contrast, nor is there a set of standard testing methods. It is just a matter of seeing which manufacturer presents a more suitable contrast to please the user's eyes. It is completely meaningless to claim ultra-high dynamic contrast. At the same time, in the future TV market, we will no longer see the parameter standard of contrast.

Having been deceived for 20 years, will you still refer to this value when buying a TV in the future?

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.