The human eye can see is a very complex physiological process, the specific formation of the visual process includes: light → cornea → pupil → lens (refracted light) → vitreous (fixed eye) → retina (the formation of objects) → optic nerve (conduction visual information) → visual center of the brain (vision). Photoreceptors according to their shape can be divided into two categories, namely rod cells and cone cells, different light intensity, the role of these two types of cells is different. At ambient light levels greater than 3 cd / m2, cone-shaped cells acted predominantly, whereas at less than 0.00 lcd / m2 the predominantly rod-shaped cells produced visual effects.
In 2002, the United States Professor Berson and other experiments found that mammalian retina does exist on the third type of photoreceptor cells - retina special photosensitive ganglion cells. Light into the human eye after being photoreceptor cells receive such photobiological effects, from this level, the intensity of light can directly and indirectly affect the biological clock, a direct impact, including physiological wake-up when the transient changes in indirect effects refers to the rhythm Of the cyclical changes.
Karin C.H.J. Smolders' experiments on brightness and mental fatigue indicate that higher light intensity can produce better mental performance as a lighting source, and is more alert than low-light conditions. The experimental requirements were tested in two experimental conditions:
1, fatigue conditions
2, the general control conditions in its two intensity 200lx and 1000lx illumination conditions
Participants came to the laboratory four times in the same time period, morning (9:00 am, 10:20 am or 11:45 am), or afternoon (13:15 pm, 14:45 pm or 16:15 pm).
Each experiment consisted of seven minutes of baseline time, 29 minutes of mental fatigue vs. control manipulation, and 200lx and 1000lx illumination of the working surface at a color temperature of 4000K and then exposed to the experimental light Environment for 30 minutes.
The results showed that subjects with different mental conditions, high illumination conditions subjective and objective subjective alertness, sense of power and the degree of awakening have an impact. In a tired mental state (ie, fatigue), a bright lighting environment can reduce people's sleepiness and improve people's ability to self-discipline, improve alertness and vitality, and thus play a positive role in the performance of the task can also be weakened due to sleep Lack of subjective fatigue caused by. Optimization of lighting parameters is beneficial to the improvement of cognition and improve a more pleasant light environment.
Figure: 200lx illumination conditions, with the degree of exhaustion trapped test
Figure: 1000lx illumination conditions, with the degree of fatigue trapped test
Figure: 200lx illumination conditions, with the degree of vitality of the experiment
Figure: 1000lx illumination conditions, with the degree of vitality of the experiment
The article points out that if a person's feelings, performance and physiological effects of high illumination are dependent on the previous state of mind, the intensity of illumination is more significant and timely for those who are in a tired working state, and the rest for resting states The test effect is slow and not obvious. The experiment provides light environment is artificial light source, and there is no daylight component, and only two kinds of illumination setting conditions, daylight conditions include a very wide range of illumination, corresponding to a more complex alertness performance range.
In addition to the potential effects of light intensity on alertness and excitement, participants also considered the assessment of the light environment for the subject, as well as the effects of light intensity on mental status and lighting levels, as well as heart rate changes. Measurement of environmental space familiarity and personal character, lighting conditions and their emotional changes between the existence of a certain functional relationship. To be sure, a certain light range, a bright light environment can improve people 's alertness, reduce the task caused by lack of sleepiness or sleepiness.