Whether the research and development of new light sources and the design of lighting engineering are successful, the key is whether the amount of illumination, spectrum, light distribution and lighting time meet the needs of people. Lighting research and practice in the past century has mainly focused on visual requirements. It has acquired a large amount of necessary knowledge in these aspects, and has developed lighting standards and corresponding light sources that meet the visual needs. But the latest research shows that the visual requirements for lighting are only one aspect, and it is very different from the circadian lighting requirements.
1 Background Circadian Rhythm The core of photobiology is the biological clock, which regulates the rhythm of daily life, such as sleeping at night and activities during the day. The circadian clock resides in the anterior bundle of the human brain and has a periodicity of 24.5 h (not 24 h). Under normal circumstances, the circadian clock is mainly adjusted by the stimulation of light. Every morning, the light adjusts the sleep-awake cycle to coincide with the day-night cycle. In complete darkness, or for blind people, the sleep-wake cycle may be different from the night-day cycle. Seasonal changes, intercontinental travel, and day and night shifts all affect the biological clock, because the light signal is out of sync with the sleep-wake cycle.
Intense light exposure can alleviate winter depression in high-drop areas, an example of circadian rhythm photobiology. In North America and North America, there is almost no sunshine in winter, and the Lewy team first found that exposure to strong light every morning and evening can alleviate depression, and more studies have shown that intense light is indeed effective. Today, light has been recognized as a treatment.
Studies by Lack and colleagues have shown that at certain critical moments of circadian rhythms, light can add sleep time and quality. VanSomeren et al. found that glare during the day and darkness during the night improved Alzheimer's symptoms. Usually this type of patient sleeps briefly and is irregular, day or night. This glare-black night treatment is a boon to both patients and caregivers.
The Badia Study Group, the Boyce Study Group, and the Figueio Study Group all showed that illuminating at night can improve nighttime work efficiency and improve subjective euphoria and activity. Public attention, sense of accomplishment, mental state, and activity are all complex concepts based on neuropsychological interactions. Therefore, experiments on the relationship between nighttime illumination and human response are extremely difficult, complex, and variable. However, this conclusion is consistent: light plays an important role in people's behavior and sense of well-being.
Over the past 20 years, these studies have confirmed that circadian rhythm photobiology research is an important area of ​​scientific research and has been gradually recognized by the public.
However, unlike vision, we have a clear understanding of visual physiology, and knowledge of circadian rhythm photobiology is still very limited.
We only know that light must enter the eye to effectively align the circadian clock, but we don't know exactly which biosensors play an important role. We track the cross nucleus from the eye to the anterior bundle, the ganglion, and the pineal gland. We believe that pineal voxels are the main hormones that signal the circadian rhythm. They are secreted by the pineal gland and closely regulated by the circadian clock, allowing people to exhibit circadian rhythms. Usually during the day, the secretion of pineal voxel is suppressed, and the person is in a state of waking; on the contrary, in the dark, the pineal voxel is secreted in a large amount, and the person is in a state of sleep. * Sleep quality 0 is also a question that many people are very concerned about. ftbigt Recently, one person suggested that the retina can also synthesize the pineal gland, but it is a 20-disc room. Outside the illuminance is far from the artificial toe Deng loses 1 about the norther who has r touch %r æ‹„p will not be aware of the use of bookmark5 in winter. However, we are not sure how pineal voxels synchronize or activate different circadian rhythm patterns. Some people think that the interruption of circadian rhythm produced by pineal voxels may be related to certain cancers.
The lack of these basic scientific knowledge will definitely affect the development of lighting sources and lighting technology. Therefore, the establishment of a lighting science and practice framework based on circadian rhythm photobiology will have a certain effect on the future development of lighting technology.
2 Light quantity, spectrum, spatial distribution, illumination time and duration For many years, it is generally believed that natural light must be better than "artificial" light. However, the results of visual research do not support this view: natural light and electric light cause the same visual stimuli. But although visual experts believe that natural light is the same as electric light, most people think that natural light is better.
The performance of the illumination light can be expressed in several main parameters: the amount of light (intensity), the spectrum, the spatial distribution, the moment of illumination, and the duration of the illumination. They have an effect on the circadian rhythm and also affect each other.
Before discussing these parameters in turn, let's briefly explain that natural light is better than artificial light in terms of its effect on circadian rhythms. This article is only the starting point for this research, and more research is needed in the future.
Light volume: The outdoor daylight intensity is high enough to regulate the cycle of the circadian clock and the pineal gland, while the indoor illumination intensity is usually too weak.
Spectral: The pineal voxel cycle is mainly regulated by the short-wave portion of visible light, and the spectrum of sunlight in this part is strong.
Light spatial distribution: Some people think that the circadian rhythm-adjusted photosensitizers appear to be evenly and randomly distributed on the retina, but some studies suggest that they are more sensitive in the lower half of the retina. Because the sun comes from the sky, it mainly shines in the lower half of the retina.
Illumination moment: The morning light synchronizes the circadian clock with the day and night cycle.
Duration of light: Nighttime light stops the secretion of pineal voxels, but will recover after the light stops.
2.1 Light quantity (strength) The main difference between artificial lighting and daylight is that the general daylight is much stronger. The work surface illumination of offices, schools, homes and factories is generally no more than 1000 lx (about 200 lx on the cornea). Generally, indoor lighting is only 1/31/5 of the above. Conversely, outdoor sunlight is at least 200010000lx, even in cloudy weather, it is above 2000lx. In good weather, the illumination near the indoor window can reach light.
Indicates the inhibition of illuminance on visual function and pineal voxels. The curve RVP on the left side of the figure is a relative visual function, obtained by experiments such as Rea. It indicates the visual function on the central fossa of the retina, ie the response speed and accuracy of the visual signal. It shows that even in the moonlight (light is weak), reading the black printed text on the white paper, the visual function remains good. Under office lighting conditions (typically 500k), the vision system processes the visual signal to near the maximum. If you only consider the visual function, it seems that there is no need to further increase the illumination.
The middle right curve is the inhibition of pineal voxel secretion, which was measured by McIntyre et al. under different illumination at night. These results are consistent with the results of other studies. They asked the subjects to observe a light box illuminated with a full-spectrum fluorescent lamp for one hour and then measure the pineal voxel content in the body. Change the illuminance in the light box to get the curve in the middle right. As mentioned earlier, it is assumed here that pineal voxel is the most important hormone for characterizing the biological clock, and its content in the human body indicates the sensitivity of the circadian rhythm photobiosystem.
It means that irradiation with 500 lx for one hour is not enough to fully stimulate the circadian system. Although this illuminance is enough for visual function. When the light is weak, increasing the irradiation time can also inhibit the secretion of pineal voxels, but it is not enough to provide good stimulation to adjust the biological clock. This result seems to indicate that the current indoor lighting standard is not enough to adjust the biological clock. People must have enough light in the morning to maintain the need to adjust the circadian rhythm. In the winter, this is a problem for people living in the north. They are still very dark when they get up. The general illumination in the workplace is only 500lx. When they go home, they are already dark. This research suggests that for a period of time, people must have more light than the visual needs.
2.2 Spectral Natural light has a different spectrum than most electric lights. The design of illumination sources for indoor lighting is mainly concerned with the efficiency of converting large amounts of electrical energy into visible light energy. But for light bulb manufacturers and lighting designers, visible light is defined by the visual light efficiency function V(in). It is the visual light efficiency function V(K). This function actually reflects only the spectral sensitivity of a small part of photoreceptor cells (cone cells, about 1% 2%) in the human eye. Experiments have shown that these photoreceptors play an important role in observing the details and color of objects. But they do not play an important role in the biological effects of circadian rhythm. Although it is unclear which photoreceptor cells are converted into circadian rhythm biological effects, studies have shown that the light efficiency of circadian rhythm system and the visual light efficiency V(K) and the dark vision light efficiency V(K) are Different, for the light efficiency of the system.
Spectral effects are still important to designers.
Table 1 Bright light efficiency function V (A) and biological clock light efficiency function Bright light efficiency V (K) light efficiency ratio 3 (1) 0K rare earth fluorescent lamp 4100K rare earth fluorescent lamp 7500K rare earth fluorescent lamp sodium sodium lamp high pressure sodium lamp incandescent red LED (yellow LED ( For the green LED (white LED (460nm + phosphor), 1 increase the light compliance of the electric light source, it will be more than 1 with t electricity, so Wish! In the research of 昼 rhythm adjustment in day and night time, / research method is very The large slave can calculate the "circadian rhythm photobiology lumens" produced by a given light source. Table 1 shows the ratio of the two lumens of several light sources.
This ratio can be used to estimate the luminous flux expressed by the apparent light efficiency to evaluate the error that may occur when the circadian rhythm photobioeffect is used. For example, with daylighting and incandescent lighting, respectively, if their luminous flux is the same (the luminous flux is defined by the visual efficiency), then daylight is more efficient than incandescent lighting from the biological effects of circadian rhythm: 2.78/1.25 = 2.22 times. For ordinary white light sources, the error is generally not more than 200%. Generally, the difference between the amount of light (light intensity or illuminance) of daylight and electric light source can reach several orders of magnitude (10000%), so the error caused by the spectrum does not seem to be very important. . However, from the practical point of view, for example, in order to achieve the effect of suppressing the secretion of pineal voxel by 50%, a fluorescent lamp of 3000 K needs to have an illumination of 500 lx on the eye (about 2500 lx on the working surface) for one hour. For 7500K fluorescent lamps, you only need 300lx illumination on your eyes (about 1500lx on the work surface). Therefore, the correct choice of light source can greatly improve the adjustment of the circadian clock.
2.3 Differences in spatial distribution, especially the study of optical spatial distribution. Although the method used was different, the results of inhibiting the secretion of pineal voxels were basically the same after conversion to the brightness of the eye. This indicates that the brightness on the eye is a key factor in determining the circadian rhythm, which was confirmed by Adler's research. He placed the light box on the line of sight, or 6 with the line of sight (the angle, when the illumination of the vertical line of sight is the same, the inhibition of pineal voxel secretion is the same in both cases. Of course, the circadian light reception is not completely ruled out now. There is less unevenness in the distribution of the device in the eye, and it has been reported that the role of the lower half of the retina may be greater.
2.4 The moment of illumination may affect the biological clock, making the phase of the biological clock early or delayed, related to the moment when the light occurs, see. When the intense light exposure occurs before the lowest temperature of the human body (the lowest temperature usually occurs in the middle of the night), the phase of the biological clock is delayed. If the light occurs after the lowest temperature, the clock phase will advance. The phase shift is related to the amount of illumination, and the phase shift is greatest when illumination occurs near the lowest point of body temperature. However, in order to achieve phase shifting, the amount of light must be controlled throughout the 24 hours. Multiple glare exposures can have the opposite effect on the circadian clock, or a complementary effect.
2.5 Illumination duration 2.5.1 Strong pineal voxel secretion inhibition Light can directly affect the regulation of pineal voxels. For several rodents, 5s of intense light pulse irradiation can cause inhibition of pineal voxel secretion.
It was found that the decrease of pineal voxels in the blood was measured about 2 minutes after 5 s intense light pulse irradiation. For humans, the earliest experiments found that after a strong light pulse, at least 10 minutes, the amount of pineal voxel in the blood will decrease. At 15 minutes after the nighttime intense light pulse is extinguished, the amount of pineal voxel in the blood will increase. Of course, due to the large blood sampling interval in the experiment, it is impossible to accurately say whether the response time is slower than the response speed of the mouse.
MeIntyre's research shows that the brighter the light pulse, the faster the inhibition of pineal voxel. It is the relationship between the level of pinealin inhibition and the illuminance on the eye and the illumination time. It can be seen from the figure that when the illuminance on the eye is greater than 1000 lx, 25% of the pineal voxel inhibition takes only 20 min; and when the illuminance drops to 500 lx, it takes exactly one hour. At the same time, it was found that no matter how strong the illumination, 50% of the pineal voxel inhibition should be irradiated for at least 30 minutes; if the illumination is less than 200lx, the inhibition of pineal voxel in the blood can hardly occur regardless of the irradiation time.
2.5.2 Phase Displacement According to the phase shift of the circadian rhythm, the latest data reported that the phase shift produced by glare illumination (eye illumination 9500k) 6.5h is the same as the phase shift of 6 hours at the same illumination for 15 minutes. This data indicates that the same phase shift can be produced under lower pineal voxel inhibition conditions. In the first case, the average pineal voxel is reduced by about 90%, while the second case is only reduced by about 20%. This phenomenon indicates that the same phase shift can be obtained with less pineal voxel inhibition. Some people think that maintaining a certain pineal voxel in the human body is beneficial to the long-term health of the human body. If this is true, then the above-mentioned intermittent glare pulse illumination can be used to adjust the biological clock.
3 Conclusions The data and research results reported in this paper allow us to start a new lighting framework based on the human biological clock. Although we use natural light as a starting point to study the effect of light on the biological clock, in the future we must study the relationship between artificial electrical lighting and the biological clock. Specifically, the lighting design must consider both the photo-biological clock effect and the visual need to optimize the lighting technology, including light intensity, spectrum, spatial distribution, light 10 or the ship can be affected by the sigh of at least a few minutes. UblJ proposed Preliminary framework. This framework should be useful, but because our effects on the photobiology clock are not yet clear, this framework can only be preliminary.
Table 2 for the day and night shift staff lighting frame lighting parameters visual paradise day shift work night shift work according to the monthly parameters of the scope of view (biological clock requirements) (biological clock requirements) low high and high light work eyes - stealing eyes at 10 (1) lx eyes at 1000Lx 100k spectral clear-field short-wave short-wavelength spectral light spatial distribution important irrelevant irrelevant illumination time according to demand early morning periodic illumination duration 12h15min pulse several times the following important issues have yet to be solved by lighting designers: the amount of light on the day and night time rhythm system What is the impact, is the quality of sleep, keeping the rhythm of the clock, observation, comfort, or working time, is daylighting the most practical, providing the illumination needed for the biological clock in the workplace, and whether the daylighting is restricted, It is best to use a full-spectrum light source containing enough short-wave visible light to illuminate. In addition to the bright-light efficiency V(K), whether the biological clock light efficiency function should be introduced as the illumination standard, vertical illumination or vertical brightness seems to reflect more on the retina of the eye. Illuminance, whether these two quantities are specified in the lighting standard In the morning, whether it is beneficial to stimulate the daytime to improve work efficiency, improve sleep at night, the clock is related to the time and duration of the illumination, and whether the lighting control should also be used as the lighting standard. There is no doubt that to answer the above questions, lighting engineering, The cooperation of experts in all aspects of lighting psychology and physiology. Research in this area has had a profound impact on the public, and they will certainly propose new lighting systems that take into account photobiological effects.
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