A brief introduction to OLED and LCD displays

dandan chu
2 min readDec 7, 2022

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LCD (Liquid Crystal Display) displays through the movement of liquid crystal molecules and backlighting, while OLED (Organic Light Emitting Diode) emits light once it is powered on.

So the main difference between them is that LCD displays need a backlight to illuminate the screen, while OLED displays can generate light by themselves.

Basic composition of LCD and OLED
Compared with LCD displays, OLED does not require external light, so it can reduce the number of CCFL backlight modules, as well as TFT glass, C/F glass and a set of substrates. Due to these characteristics, the structure of the OLED display is simpler, lighter, and power-saving.

OLED and LCD displays

In the era of full screens, OLED displays are more popular. And this is also related to fingerprint recognition technology. Because this technology needs to see through the display, the thinner the display, the better. That’s why OLED displays are favored. All in all, OLED displays are better for smartphones.

The structural difference between LCD and OLED
However, not all OLED displays are perfect. LCD display has 3 panel types: TN panel, VA panel, IPS panel. There are also 2 types of OLED displays: AM active and PM passive. Although AMOLED plays a leading role in the market, the display effect of AMOLED still varies from manufacturer to manufacturer.

Why AMOLED have different display effects?

P-array of AMOLED: When it comes to the shortcomings of AMOLED, the first thing people think of is the P-array, that is, the Pentile array. Samsung is the first company to mass-produce OLED panels and use P-array. The Galaxy S4 first used a P-array called Diamond Pixel, which took a different path from the standard RGB arrangement.

RGB type and P array
Simply put, the RGB type arranges the sub-pixels of the three primary colors of red, green, and blue evenly, and the RGB sub-pixels are not evenly arranged in the P array, but share pixels, so the actual pixel density of the P array is higher than that of the RGB Low. This has led to the fact that even at the same resolution, the P-array OLED display is not as clear as RGB, so it is often called “big fruit color-changing screen”.

To sum up, do you have a preliminary understanding of LCD and OLED displays?

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