EIZO

LED backlight causes eye fatigue?

Since the popularization of LED backlights, the number of people who report eye fatigue caused by flicker has increased. Some people perceive the high speed at which the LED backlight flashes as flicker. Of course, even those who cannot perceive flicker may also be affected by it without realizing it.

How does flicker work?

Dimming (brightness control), is separated into 2 categories: PWM (pulse-width modulation) and DC (direct current).

LED monitors often use PWM. The design is simple and easy to mass produce.

Does flicker really cause eye fatigue?

We conducted an experiment to find out how users felt about viewing variable light.

Source: Kitasato University (Japan), School of Allied Health Sciences (n=10)

Did you perceive flicker?

Did you feel eye fatigue?

Lastly, which was the easiest to view?

At EIZO…

We have developed a hybrid model that combines the pros of PWM and DC dimming.

A bright screen causes eye fatigue?

At first glance, a bright screen seems clear and easy to see. However, a screen that is too bright is a primary cause of eye fatigue. On the other hand, if a display is too dark it is too difficult to see and also adds to eyestrain. At EIZO, we tested the effects of our Auto EcoView, which automatically adjusts the screen's brightness to an appropriate level in response to ambient lighting.

Source: Kitasato University (Japan), School of Allied Health Sciences

Did you perceive flicker?

How was the level of fatigue and the readability?

At EIZO

Most of our general-purpose monitors come equipped with Auto EcoView, a brightness sensor. Auto EcoView ensures the screen is never too bright or too dark; it automatically adjusts the screen's brightness to the optimum level, alleviating eye fatigue caused by working at the computer for long hours.

Blue light causes eye fatigue?

How blue light influences eye fatigue is an increasingly popular topic. First we will show where blue light falls on the light spectrum.

Blue light is part of the visible spectrum and has a wavelength that is close to that of ultraviolet light.

99% of the ultraviolet rays that reach the Earth are UVA with a wavelength of 315 - 400nm. Although blue light is part of the visible spectrum, it still has an influence on eye fatigue. Since its wavelength puts it close to UVA, it is conceivable that it could cause strain on our eyes.

When comparing the relationship between LED and blue light, we have confirmed that LED backlights and CCFL backlights have about the same amount of blue light.

How to reduce blue light on an LCD monitor

Knowing that blue light influences eye fatigue, we tested how much we could decrease the amount of blue light by making adjustments to the monitor.

Lowering the color temperature

Lowering the color temperature causes light distribution to shift towards longer wavelengths (more reddish colors). When we change the initial color temperature of our monitors (6500 - 7000K) to 5000K...

Lower Color Temperature and Brightness

By lowering the brightness you can reduce overall energy usage. When we adjust the monitor's brightness down from the highest setting to an adequate value (approx. 20 cd/m², and the color temperature to 5000K...

At EIZO

We greatly adjusted the monitor's brightness and color temperature resulting in a reduction of the effects of blue light using various technologies. We were able to create a comfortable viewing environment with Auto EcoView automatic brightness adjustment and Paper mode, part of Fine Contrast presets.