Brightness, also known as luminance, refers to how bright a light or an object looks to human eyes, that is, the level of “light”. When the surfaces of any two objects look equally bright, we can say that they have the same brightness. Since there are many factors affect brightness, it is not easy to measure. These include a smooth surface tending to look brighter than a rough surface in the same environment, so illumination is generally used as the basis for comparison. Illuminance refers to how much light (luminous flux) is received in a certain area. Simply speaking, it means “the brightness of the brightened place.” The unit for measuring illuminance is “Lux”. The higher the value, the brighter it is, and lower values indicate darker.
The level of illuminance has a huge impact on the reading situation. Research by the National Taiwan University of Science and Technology indicates that whether it is a hard copy or electronic ink, the eyes can recognize the text of the book more quickly and accurately in an environment with higher illuminance level. At the same time, smaller text font requires a higher level of illuminance. The level of illuminance has a more significant impact on the efficiency of reading when the text font is smaller.
When using consumer electronic products such as computers, tablets, mobile phones, etc., which have bright screens, if the ambient illumination is too low and has great contrast with the illuminance of the screen, it will easily cause glare. Although the study has not proven that glare will cause long-term damage to the eyes, it still makes the eyes tired and uncomfortable, and reduces efficiency at work indirectly. Therefore, use of consumer electronic products in an environment with insufficient illumination should be avoided.