What exactly is going on with the "pot" that burns the screen?
In the first half of the year, the most important case of OLED TV screen burn-in was mainly this: an OLED TV used at Incheon Airport in South Korea had a screen burn-in due to long-term display of flight information. As a result, the supplier replaced it with an LCD TV. This OLED product is new in 2018 and was installed at the beginning of the year. Due to the long-term display of flight information, although the page is frequently switched, the top navigation bar remains basically unchanged, resulting in a relatively obvious white horizontal line running through it. ——Big Screen Jun thinks that this "OLED to LCD" is very embarrassing. But it may not be the supplier’s idea, it may be the “user’s” request.
Regarding this case, Dapingjun came to an interesting conclusion: the scene was not an OLED TV, but the screen burnout was a product. It would be obviously unfair if OLED technology takes the blame. This case seems more like the extreme manifestation of "individual product differences" caused by insufficient technological maturity and stability.
What exactly is screen burn? Actually there are two reasons!
As for the problem of screen burn-in, the earliest attention was paid to plasma TV technology. However, previous CRT TVs would actually burn the screen - but without a second product option, the market could only pretend that there was no such problem. In this regard, Big Screen Jun feels that plasma PDP TVs and OLED TVs are a bit "untimely". They have caught up with the competition in liquid crystal technology, so "burn or not" has become a competitive force and has attracted widespread attention.
The current explanation for screen burn on the Internet is basically the result of "uneven aging" of pixels: that is, when displaying some pictures, especially when displaying still pictures for a long time, some pixels are highlighted, some pixels have low brightness, or are even turned off. This creates a line or "station logo" imprint.
In this regard, Big Screen Jun noticed that some netizens have raised questions: Since it is "uneven pixel aging", the burn-in mark should be "darkening in color and brightness". Why do many on-site photos of screen burn-in show that "the burn-in area becomes brighter instead"? The knowledge here is that there are actually two reasons for screen burn-in, three major types. Regarding this, please listen to Mr. Daping’s detailed explanation:
The first cause of screen burn-in is "aging of luminescent materials," such as phosphors or ultraviolet excitation devices in plasma TVs, and OLED materials in OLED TVs. The general reaction to the aging of this part is that when the screen displays the picture, the brightness of the corresponding part is insufficient.
The second reason for screen burn-in is "aging of the drive structure." Both plasma TVs and OLED TVs have a "pixel self-illuminating" structure. This causes the pixels to continuously consume power - what is often referred to as "current drive" in the industry. Relatively speaking, the screen pixels of LCD TVs are just light valve switches. The working method of "using voltage to drive the crystal rotation angle position" consumes very little energy - the power consumption of LCD TVs is mainly reflected in the backlight, which is what the industry calls "voltage drive".
As a driving device, does its working state remain unchanged throughout its life? The answer is of course no. In particular, current-driven components have relatively high work performance, which can easily lead to device aging or even failure. On large LED display screens and self-illuminating display products, isn't it easy to see driver-damaging faults such as local "bright lines and dark lines"? The aging or reduced stability of this kind of driving device can often lead to the phenomenon of screen burn-in and high-brightness marks.
Therefore, Big Screen Master would like to point out that the so-called "uneven aging" of screen burn-in actually includes two situations: uneven aging of the driver and uneven aging of the illuminator - these are the two causes of the screen burn-in phenomenon. And sometimes, some screen burn-in phenomena are mixed with the above two reasons, which becomes the third mixed type of screen burn-in.
Of course, for users, no matter what the cause of your screen burn is, the result is the same. However, for manufacturers, different causes of screen burn-in mean different response strategies.
How to solve the screen burn problem, there are many tricks
When it comes to the problem of screen burn-in in TVs and other display devices, you can often see manufacturers saying "it is solved through software algorithms." In other words, software algorithms have become the most frequently seen “screen-burning nemesis”. But are software algorithms really so important?
First of all, Dapingjun believes that the most fundamental way to solve the problem of screen burn-in should rely on "good basic product quality." For example, regarding the phosphor issue of plasma TVs, the lifespan and stability of organic phosphors and inorganic phosphors are obviously different. Regarding the illuminant materials of OLED TVs, different materials and different process technologies will also lead to differences in "lifetime" and "stability" - try to develop OLED materials with higher lifespan and stability. This is the fundamental solution to the problem of "uneven aging of the illuminator".
At the same time, in the selection of driving devices and technologies, high stability and redundancy are the basic principles. For example, if a single OLED pixel is required to be brighter, it is necessary to provide a better "electron mobility" indicator for the load capacity of the driving circuit of this pixel. This indicator is also the core performance difference between metal oxide TFT and amorphous silicon TFT. That is, continuously improving the load-bearing capacity of the driving part is one of the fundamentals to prevent "non-uniform aging and screen burn-in".
The above two aspects, for OLED display technology, are mainly reflected in the "maturity and experience of the industrial chain system". That is to say, as the research and development of OLED products continues to deepen, it is foreseeable that the technical level of OLED materials, necessary driving components and materials, and processes will continue to be improved and improved.
Secondly, Daping Junjun certainly believes that "software algorithm" is very important - but it does not refer to the software algorithm that "dithers the position of the screen" and "reduces the aging of the station logo", but refers to the software algorithm of "device life management".
Once OLED materials and driving devices have high lifespan and performance redundancy, the "local accumulated work intensity value" can be known through software, and the performance redundancy can be used to achieve "performance compensation after uneven aging" through software algorithms. ——This software algorithm is more similar to "working condition management of each pixel". It is a technology that actively overcomes the impact of screen burn-in, and its effect is naturally very significant.
However, Dapingjun would like to explain in particular: the effectiveness of the software algorithm must be based on the high redundancy of the performance of the "materials and devices" themselves. Without advancements in materials, processes and other technologies, “who can software algorithms count against?” The progress of OLED TV "materials and devices" is a "key sign" of industry maturity.
In other words, Big Screen Master believes that the so-called screen burn-in problem of OLED TVs is more a product of the insufficient accumulation of technology, materials and experience in the early stages of the industry. With the advancement of technology and the improvement of maturity, its display effect will inevitably be better - even, this rule has also appeared in the history of "LCD" TVs!
Some dirty facts: Who said LCD TVs don’t burn the screen?
Criticisms of screen burn-in on OLED TVs are mainly directed at LCD TVs that do not have screen burn-in. However, big-screen fans would like to point out that LCD TVs are not inherently free of screen burn-in.
On the one hand, LCD TVs will also have point defects, linear picture defects, and flaky picture defects. Because, during the application process, although the liquid crystal is driven by voltage, it is difficult to ensure that the driving structure will not experience "aging and performance loss" beyond the normal range, resulting in major failures on the display screen.
On the other hand, LCD TV imaging relies on a backlight system. In early cold cathode backlight systems, problems such as "local lamp aging and brightness attenuation" may occur, resulting in horizontal uneven brightness on the display screen. Later LCD TVs used a large number of LED light sources, and the many lamp beads used in the LED light sources were difficult to ensure that the aging curve was completely consistent, or that individual lamp beads would not fail. Once the above problems occur, LCD TVs will suffer from patchy uneven brightness problems.
For LED-backlit LCD TVs, how to solve the above "non-uniform aging" problem? The answer is to use redundant performance and lifespan design, relying on software algorithms to adjust the status of different LED lamp beads, to achieve a relatively consistent backlight effect - this is "the same idea" as the technology to prevent the screen burn-in effect on OLED TVs.
In other words, today’s so-called myth that LCD TVs do not burn out the screen is not “inevitable”, but is based on the high maturity of LCD technology. It is the development history of LCD TVs for more than 20 years that has given LCD technology the almost excessive performance and stability it has today. Comparatively speaking, OLED TV is still in its infancy, and its development and maturity still need time to accumulate. Dapingjun likes this sentence very much, "Don't bully young people into poverty." Because teenagers are the future. Although LCD is beautiful and even perfect, after all, it belongs to yesterday and today's era, while OLED TV belongs to tomorrow and the next era.
ANNA