Difference
In short, LEDs, LCD screens use backlights to illuminate their pixels, while OLED pixels are actually self-illuminating. You may have heard that OLED pixels are called “self-illumination” and LCD technology is “transmissive”.
The light emitted by the OLED display can be controlled pixel by pixel. LED liquid crystal displays cannot achieve this flexibility, but they also have disadvantages, which Topfoison will introduce below.
In lower cost TV and LCD phones, LED liquid crystal displays tend to use “edge lighting” where the LEDs are actually located on the side of the display rather than on the back. Then, the light from these LEDs is emitted through the matrix, and we see different pixels such as red, green, and blue.
Brightness
LED, LCD screen is brighter than OLED. This is a big problem in the TV industry, especially for smart phones that are often used outdoors, in bright sunlight.
Brightness is usually measured in terms of “nits” and is roughly the brightness of a candle per square meter. The typical peak brightness of the iPhone X with OLED is 625 nits, while the LG G7 with LCD can achieve a peak brightness of 1000 nits. For TVs, the brightness is even higher: Samsung’s OLED TVs can achieve brightness of more than 2000 nits.
Brightness is important when watching video content in ambient light or sunlight, as well as for high dynamic range video. This performance is more suitable for TV, but as mobile phone manufacturers increasingly boast of video performance, brightness is also important in this market. The higher the brightness level, the greater the visual impact, but only half the HDR.
Contrast
If you place the LCD screen in a dark room, you may notice that some parts of the solid black image are not actually black, as the backlight (or edge lighting) can still be seen.
Being able to see unwanted backlights can affect the contrast of the TV, which is also the difference between its brightest highlights and the darkest shadows. As a user, you may often see the contrast described in the product specifications, especially for TVs and monitors. This contrast is to show you how bright the white color of the monitor is compared to its black color. A decent LCD screen may have a contrast ratio of 1000:1, which means that white is a thousand times brighter than black.
The contrast of the OLED display is much higher. When the OLED screen turns black, its pixels do not produce any light. This means that you get unlimited contrast, although its appearance looks great depending on the brightness of the LED when it is lit.
Perspective
OLED panels have excellent viewing angles, mainly because the technology is very thin and the pixels are very close to the surface. This means you can walk around the OLED TV or stand in different parts of the living room and see the screen clearly. For mobile phones, the angle of view is very important, because the phone will not be completely parallel to the face when in use.
The viewing angle in the LCD is usually poor, but this varies greatly depending on the display technology used. There are currently many different types of LCD panels on the market.
Perhaps the most basic is the twisted nematic (TN). This technology is commonly used in low-end computer displays, inexpensive laptops, and some very low-cost phones. Its perspective is usually poor. If you’ve ever noticed that the computer screen looks like a shadow from some angle, then it’s probably a twisted nematic panel.
Fortunately, many LCD devices currently use the IPS panel. IPS (Plane Conversion) is currently the king of crystal panels and generally provides better color performance and a significantly improved viewing angle. IPS is used in most smartphones and tablets, a large number of computer monitors and televisions. It is worth noting that IPS and LED LCD are not mutually exclusive, just another solution.
Color
The latest LCD screens produce fantastic natural colors. However, like the perspective, it depends on the specific technology used.
The IPS and VA (Vertical Alignment) screens provide excellent color accuracy when properly calibrated, while TN screens often don’t look so good.
The color of OLEDs does not have this problem, but early OLED TVs and mobile phones have problems in controlling color and fidelity. Today, the situation has improved, such as the Panasonic FZ952 series of OLED TVs even for Hollywood color grading studios.
The problem with OLEDs is their amount of color. That is, a bright scene may have an impact on the ability of the OLED panel to maintain color saturation.
