In mobile phones, TVs and other products, the key to technology level and price differentiation is the display screen or display panel. Any changes in resolution, supplier, etc., brightness, color gamut, etc., may be critical. cost.
In these years, the two hottest words in the panel field are OLED and HDR (high dynamic range). If two technical points are combined in one product, the high-end identity will be on the paper.
However, PCwolrd, HOP, etc. recently pointed out that OLED panels that support HDR technology, especially TVs, may have a much longer lifetime attenuation.
Here, some basic knowledge is first laid out. First, an obvious feature of the output HDR display is rich detail. The OLED has a natural advantage over the LCD panel in black (which can be completely non-illuminated) due to its self-illuminating characteristics. Supporting HDR also means that the peak brightness of the OLED panel needs to reach a relatively high level.
Second, several key variables that affect OLED lifetime include current magnitude, operating temperature, and brightness. According to a lighting technology document from the US Department of Energy (DOE) in 2016, an OLED panel with a peak brightness of 8300 nits has a working life of 40,000 hours at 25% brightness (2075 nits), but only 10,000 at 100% brightness. Hours, this reflects a linear relationship.
Based on this, let's discuss how HDR-enabled OLED panels (assuming they are always in a cool, current-normal condition) will change in life.
PCworld has tested Sony's 65-inch A1E OLED TV (31999 yuan), and the peak brightness under the standard dynamic range (SDR) is only 170 nits. However, when playing HDR video, the brightest area even has a 700 nit pole. The value is 4.1 times earlier.
However, the conclusion of the DOE can not be directly applied here, because playing HDR is a dynamic process, the picture is not real-time uniform and the brightness is always in dynamic change. It may be assumed that the 700 nits brightness will occupy 5% of the total duration, and the HDR content will be evenly presented. After conversion, the 100,000-hour OLED panel of Sony will lose 20% of the theoretical life due to playing only HDR video.
The above is only a theoretical deduction. For OLED TVs, with the attenuation of sub-pixels and substrates, in fact, in order to maintain the same brightness in the middle and late stages, the current of the excitation light is increased, and naturally the heat is increased. .
At present, the only manufacturer that manufactures large-size OLED TV panels is LG, but the OLED panels of LG's TV panels and mobile phones are not the same. The former does not have pure red, green and blue sub-pixels, but the white pixels are added with filters. The disadvantage of this approach is that it reduces the brightness, so LG fills up the white pixels to brighten, which in turn causes desaturation.
For OLED panels, only LG has publicly promised 100,000 hours of life in 2016 (ie 10 hours a day, at least 10 years +), but this is sacrificed at 50% brightness.
Although this article talks about a lot of HDR's detrimental side effects on OLED lifetime, for most consumers, there is no need to worry, because it may be difficult to meet. However, if you are driving TV 24 hours a day or 7x24 hours for other purposes, be careful, traditional LCD TVs may be more suitable.