Reader Xiong Bin: Dear Scientist, hello! There is a saying circulating online that using LCD screens on mobile communication devices is more eye-friendly than using OLED screens. Is this statement true?
Lu Canzhong: The claim that LCD screens are more eye-friendly than OLED screens is likely based on the issue of flicker. LCDs display images by illuminating the liquid crystal layer through a backlight layer, typically using direct current dimming (DC dimming) to adjust brightness by controlling current or voltage. Since the backlight remains continuously on, flicker does not occur, resulting in relatively less eye strain.
In contrast, each pixel in an OLED screen emits light from organic materials without the need for a backlight. However, changes in current or voltage can cause chromatic shifts in the pixels, which means OLED screens typically cannot use DC dimming and instead rely on pulse-width modulation (PWM) dimming technology, which simulates brightness changes by rapidly switching pixels on and off. This dimming method can lead to flicker, which, although difficult to perceive with the naked eye, can cause eye fatigue and headaches through continuous perception by the nervous system.
Regarding the reduction of harmful blue light radiation, OLED screens have certain advantages. The backlight layer of LCD screens contains a higher proportion of short-wavelength blue light (415-455 nanometers) and cannot independently adjust the brightness of individual pixels, leading to stronger harmful blue light radiation. In contrast, OLED screens have relatively longer blue light wavelengths and a lower proportion of harmful blue light, and their self-emitting characteristics allow for a reduction in total blue light by controlling pixel brightness. For example, when displaying dark images, non-emitting areas do not produce blue light, resulting in overall lower blue light intensity.
Therefore, the impact of LCD and OLED screens on the eyes has its pros and cons, and it cannot be simply stated which type of screen is absolutely more friendly. It is necessary to judge and choose based on the usage scenario and personal needs. LCDs perform better in avoiding flicker, so if one is sensitive to flicker or needs to read for extended periods (especially at night), it is advisable to choose electronic products with LCD screens.
On the other hand, OLED screens have advantages in blue light control. If display quality and reducing blue light hazards are priorities, OLED screens should be chosen, especially those with high-frequency PWM or quasi-DC dimming technology, which can somewhat alleviate flicker.
It is important to emphasize that regardless of the type of display, prolonged use will impose a certain burden on the eyes. The impact of screens on the eyes is not merely a comparison of technical parameters; the usage scenario and personal eye habits are key variables. Paying attention to controlling time and maintaining eye hygiene may be even more critical.
With superior display performance such as flexible form, high contrast, fast response, and wide viewing angles, OLED has replaced LCD as the most mainstream display technology for smartphones, becoming the primary medium for daily visual information exchange. With further advancements in OLED technology (such as reduced blue light pixel power consumption and improved material stability), OLED is expected to achieve a more eye-friendly and healthier visual experience through technological innovation while maintaining its display advantages in the future.
Source: “Learning Power” Learning Platform, China Science Daily
