Talking about the Influence of Blue Light Illumination on Long-term Visual Work
Fudan University Institute of Electric Light Sources, Shanghai
Abstract: This paper analyzes the characteristics of long-term visual operations, and analyzes the effects of appropriate blue light illumination on improving lighting efficiency and reducing operator fatigue in low illumination environments from the perspective of visual effects and biological effects of illumination. For lighting in areas such as hospitals and military operating rooms, it is advisable to use blue light sources or higher color temperature light sources.
Keywords: visual work, blue light, biological effect, work efficiency, safety
1. Long-term visual work features
At night, when most people start to rest, the night shift workers in many factories continue their work. They want to ensure the normal operation of the assembly line that works day and night to complete the assembly and installation of parts to ensure the production of the products. Factory.
Not only factories with flow operations, but also many large industrial operating areas such as nuclear power plants, coal mines, automobile factory workshops, as well as night-time cockpits for aircraft and automobiles, military-controlled operating rooms, hospital operating rooms and inspection rooms, the operating objectives remain clearly visible. It has an important impact on the operator's accurate and fast operation. On the other hand, long-time visual operators are prone to fatigue, and the decline in productivity due to fatigue has not caused people's attention, and major accidents caused by misoperation caused by fatigue have forced people to The issue is of particular concern. The Three Mile Island nuclear accident occurred at four in the morning, and the Chernobyl nuclear leak occurred at 1:32 am, when the night shift workers were just tired and began to doze off.
Not only at night, many visual operations are indoor operations, even in the daytime, artificial lighting is required, and the lighting effect cannot be completely comparable to natural lighting. If the lighting level is not enough, the visual characteristics are insufficient to cause an increase in the operational error rate or speed. Reduced; even with higher illumination to ensure better visual characteristics, the operator is more prone to fatigue in artificial lighting environments after prolonged operation. The consequences of such fatigue for operators who sit in front of precision instrument panels or military bases for long periods of time are unimaginable.
Therefore, for a long-term visual work environment, in order to ensure efficient and safe operation, good illumination is required to ensure the operator's visual characteristics; and a work environment that can appropriately alleviate the operator's fatigue level should be ensured. The former is well known to us, and the lighting should meet certain standards to meet the visual effects of people. Then the latter, in addition to improving the other hardware conditions of the working environment, what can lighting do to ease the operator's fatigue? The results of research in recent years show that the illumination is closely related to melatonin secreted by the pineal gland in the human body. It controls the biological clock of the human eye, and proper illumination can alleviate human fatigue. Therefore, for the lighting design of long-term visual working environment, not only its visual efficiency but also its biological effects should be considered (van Bommel, 2003 [4]).
1. Visual effects and biological effects of illumination
Within a long period of time, it is believed that there are two kinds of photoreceptors on the retina of the human eye, namely a cone and a rod. The cone is divided into a red cone, a green cone and a blue cone according to its sensitivity to different wavelengths. The cone system has low sensitivity to light, starts to function at sufficient brightness, plays a leading role in bright vision, and can accurately distinguish the fine structure and contour of the object with high spatial resolution. The rod system is highly sensitive to light and dominates in low light. It cannot distinguish colors, and the object has only a rough outline and poor accuracy (Shou Tiande, 2001 [5]). The different properties of the cone system and the rod system allow the human eye to have different visual characteristics at different levels of illumination. Since the combined sensitivity of the three cones is maximized at a wavelength of around 555 nm, the rod has the greatest sensitivity to stimuli with a wavelength of around 507 nm. When the brightness is lowered, the sensitivity curve of the human eye to the spectrum moves toward the short-wave direction, which is the famous Purkinje shift. Figure 1 shows the spectral light efficiency curve of the human eye at different brightness levels (Sagawa, 1989 [2]).