OLED screen we have basically seen, cell phones and TV screen applications more, compared to traditional LCD LCD screen, OLED screen has a wide color gamut, pure color, excellent black control, ultra-high contrast, very low response time and other advantages, is the best display screen type (Micro-LED has not been commercialized).
But OLED screen is not perfect, due to material relations, W (white) R (red) G (green) B (blue) four-color pixel life will be over time the brightness decay.
The pixel composition of an OLED TV
Note: Although the OLED TV pixel dots are composed of four colors, the four colors will not be lit at the same time, but at most three at the same time, from left to right in the figure are blue, white, red and green.
When a certain area of the screen for a long time (hundreds of hours) display a fixed picture, the brightness of the pixels in this area will decay faster than other places, resulting in a dark spot on the screen can not be recovered, which is often referred to as the OLED screen burn phenomenon.
The following chart is a well-known TV evaluation agency RTINGS to do up to two years of OLED TV burn-in test, the four corners of the logo light 20 hours a day, seven days a week, has lasted 122 weeks, is a very harsh aging test. As you can see, the white letter “R” for example, due to tens of thousands of hours of lighting, the “R” letter in the area of the pixel dots have been aging, the brightness has become lower, in the gray solid color chart shows a clear black mark.
In fact, at the sixth week (900 hours), the screen was already showing “burn-in” that could not be recovered.
Note that the model used for the RTINGS test is a 2017 product,.
See here, the reader is not thinking how OLED TV so brittle, it does not feel like using a long time?
In fact, the aging test method used by RTINGS is far from our actual daily use, we do not use OLED TVs to such an extreme, so RTINGS also conducted a closer to the real use of the environment of the aging test:.
Using six LG OLED C7 TVs, respectively play 200 nits / maximum brightness CNN news programs, soccer programs, live NBC programs, FIFA 18 games, Call of Duty games six screen, the following is 102 weeks (more than 9,000 hours of power on time) after the results
Test results from RTINGS
From the graph, we can find that if you watch live TV programs for a long time, the subtitle area, the station logo area, and the character area on the screen such as long-term highlighting areas have more serious screen burning.
Test results from RTINGS
As for games, soccer, movies, TV shows and the like, the aging rate of each pixel is relatively average due to fast screen switching and unfixed images, so even with tens of thousands of hours of use, the screen burning situation is still relatively mild.
By 2020, as technology advances, the organic materials used in OLED TVs are getting longer and longer, and LGD and other OEMs already have a lot of technical means to help users avoid screen burn-in situations.
OLED TVs may have pixel decay asynchrony problems include temporary image retention and burn-in, both of which can occur on any display device, strictly speaking. Image Retention means a mark that will be visible for a short period of time, but will gradually heal itself after shutdown and displaying the transformed content. Screen burn-in, on the other hand, leaves a permanent and indelible mark. Displaying high-brightness still images for a long time is the main cause of the problem. Preventive measures are mainly the following, although different brands of OLED TVs are called by different names, but the role is the same.
Pixel shift (Pixle Shift).
OLED screen will let the screen as a whole pixel shift one or two pixels to avoid the screen in the fixed image (such as the station logo, blood stripes, etc.) caused by the screen burning screen situation, this function is mandatory.
Logo Luminance Adjustment (Logo Luminance Adjustment).
Station logo and watermark often appear in TV programs and sports programs, when the TV detects the presence of Logo, avoid image residue by reducing the brightness of this area.
Pixel Refresher: Pixel Refresher.
There are two modes, manual and automatic. Taking LG’s OLED TV as an example, after a cumulative use of 4 hours, there will be a refreshing process of about 7-10 minutes to eliminate the image residue when the TV is turned off. If users find that there are marks that cannot be automatically eliminated, they can use manual pixel refresh, which takes longer and clears more thoroughly, but is not recommended for frequent use.
Automatic Brightness Limiting (ABL).
Full name AUTOMATIC BACKLIGHT LIMITER, translated as “automatic brightness limit” may be more appropriate, as HDR video content more and more, OLED TV display higher peak brightness is gradually increasing, ABL in the detection of high brightness continues for a period of time, will gradually reduce the brightness, which can avoid organic materials in the higher temperature work, delaying the appearance of image residue.
In terms of the current OLED technology in 2020, the use of new materials to improve the life of the pixel point, coupled with a variety of technical means of prevention, OLED TV life has been greatly improved, under normal conditions of use (try to ensure that the TV will not appear for a long time stationary image elements, such as extremely frequent viewing of live TV stations), combined with the results of rtings test (more than 9000 hours of power on), with an average of four hours of use per day, OLED TV can be at least 6, 7 years without burning screen, which is almost the same as the life of the LCD TV.
Of course I’m not saying that OLED TV can only use 9000 hours, after all, this test RTINGS is still continuing to do, I think 15000 hours is not a problem.
Some additional content.
Current OLED TV screens are almost all from LGD.
Almost all current OLED TVs use DC dimming (no screen flash).
OLED screens have near-perfect DCI-P3 color gamut coverage.
W (white) R (red) G (green) B (blue) four-color pixel life is not the same, luminous efficiency is not the same, so in order to ensure the effect of the picture, the four-color pixel luminous area is not the same, blue pixel efficiency is the lowest life span is the shortest, so the area is larger, red in the middle, green and vice versa. However, in the RTINGS test, the red sub-pixel degraded the fastest, followed by the blue, and then the green.
Finally, hats off to RTINGS for doing such an expensive test and bringing an important shopping reference for consumers, which has been topped up for RTINGS. Their website is http://www.rtings.com