1. LCD 与 OLED
If you want to explore the pros and cons of the two, you must first know that the two are different products, and they are different in the principle of light emission.
LCD, the full name of Thin Film Transistor Liquid Crystal Displayer (Thin Film Transistor Liquid Crystal Displayer), generally referred to as LCD (Liquid Crystal Display), it dominates the time before the appearance of OLED for nearly 20 years.
The luminescence of LCD mainly relies on its backlight layer, which does not have luminescence characteristics. The backlight has only white, so it is necessary to add a layer of color filter to project the three primary colors.
At the same time, in order to control the ratio of red, green and blue, it is necessary to add a liquid crystal layer for adjusting the voltage between the backlight layer and the color light sheet.
Let’s look at OLED screens. OLED is called Organic Light-Emitting Diode. Unlike LCD, OLED uses self-luminous technology, that is, when electricity flows through, countless small light bulbs can emit light. (The three sub-pixels of red, green and blue form one pixel).
2. The difference between LCD and OLED
2.1 Color display
As mentioned above, LCD has a liquid crystal layer, and this liquid crystal layer cannot be completely closed, so when the LCD displays black, the liquid crystal layer still has light through, so when the LCD displays black, various colors are mixed. The class is gray.
The OLED screen is a more pure black because the pixels are self-luminous. When displaying black, the pixels are powered off.
The same is true for color display, the color of OLED screen will be more pure and bright, and LCD due to the existence of the filter layer, the color saturation is naturally not as good as OLED.
2.2 Thickness
The OLED screen does not need a backlight layer and a liquid crystal layer, so it can be made thinner than an LCD screen, and it can be bent. It is reflected in the mobile phone that the frame and chin can be made narrower.
The popular COP and COF packages in the past two years are also the case, including waterfall screens and curved screens launched by various companies that rely on the flexible characteristics of OLED screens.
2.3 Strobe
Previously, OLED screens have always used PWM dimming, that is, the brightness of the screen is changed by alternating the on and off of the screen. Since the light and dark alternate fast enough, beyond the human eye's perception range, when the brightness is high, the human eye can't detect it, and the strobe can only be seen under the camera lens. However, when the brightness is low, the stroboscopic will be more obvious, and the more sensitive people will feel the eye discomfort caused by the stroboscopic. Fortunately, since last year, the Android camp has popularized DC dimming, that is, through software algorithms, changing the power of the panel circuit to change the brightness of the screen, which greatly reduces the OLED screen flicker problem, even like Redmi Introduced the hardware DC dimming and integrated the self-developed algorithm into the screen driver IC.
2.4 Burn screen
If the stroboscopic OLED screen has almost been overcome, then "burning screen" is another flaw that OLED is difficult to solve.
"Screen burn" is also called "after-image", the root cause of which is the different life cycles of light-emitting components. The lifespan of the red, green and blue sub-pixels in an OLED panel are not consistent, and the wavelengths and required currents of the three sub-pixels are also different. Therefore, when displaying fixed content for a long time, the blue pixel ages faster than the other two pixels, resulting in color Offset, it is easy to leave "pixel afterimage".
2.5 Power consumption
In terms of power consumption, the OLED screen is lower than the LCD screen, because the pixels of the OLED screen work independently, and the LCD screen is fully backlit, so the OLED screen is more energy-saving and environmentally friendly than the LCD screen.
2.6 Pixel arrangement
In the LCD screen, the standard RGB pixel arrangement is adopted, and the three pixels of red, green and blue are closely adjacent, so when the content is displayed, the accuracy is accurate and the edges are clear.
In an OLED screen, because the lifespan of the three sub-pixels is inconsistent, they cannot be made into the same size. Generally, the area of the blue and red sub-pixels is increased, thereby increasing the lifespan of the blue and red pixels.
But this also causes the overall pixel density to be inferior to LCD screens, and the effective sub-pixels are reduced by about one-third.
In other words, the same resolution is 1080p, which can be seen as a real 1080p on the LCD screen, while on the Samsung OLED screen, the actual pixels may only be 80% of 1080p. In domestic screens that use other arrangements Above, this number is lower.
It can be seen that even if the OLED screen is about to replace the LCD screen today, it still has many imperfections. The LCD screen is also slightly behind in many aspects, and the two are destined to be good and bad.
Therefore, in the future, there will be new screen technology to replace these two.
3. Mini LED
Mini LED refers to a diode whose size is less than 0.2 mm. This means that compared with LCD, mini LED panel lights will use more LEDs, which can bring good wide color gamut performance, high contrast, high dynamic range and local dimming function, and the service life will be longer than that of OLED screens. long.
4. Micro LED
If mini LED is a continuous upgrade of LCD (because they are all backlight technology); then Micro LED is a continuous upgrade of OLED, because Micro LED is also a self-luminous technology.
Micro LED can make the LED unit smaller than 100μm, much smaller than OLED and mini-LED. And it uses inorganic gallium nitride material, which has a longer lifespan and no burn-in problem.
In theory, its brightness is 30 times higher than that of an OLED screen, and its response speed, resolution, and color saturation have been greatly improved, and its power consumption is also lower than the existing screen.
5. Development route
CRT -> LCD -> OLED -> Mini LED -> Micro LED