Non-visual Biological Effects Research Articles

Aydınlatma alternatiflerinin insan odaklı aydınlatma açısından değerlendirilmesi: Büro örneği

In addition to its visual effects, light also has non-visual biological and behavioural effects. Nowadays, human centric lighting that takes into account the visual and non-visual effects of light has gained in importance. However, in this context there is no consensus on the appropriate illuminance and colour temperature of light according to the function. In this study, four static and one dynamic lighting scenarios were designed in a mock-up room in order to investigate the lighting conditions applicable to offices. These scenarios with different illuminances and colour temperatures were compared through surveys and lighting calculations. The research was planned for two separate conditions; long-term and short-term study. Each lighting scenario was applied for two weeks in the long-term study and twenty minutes in the short-term study. In addition to the emotional states of the participants, the lighting conditions were also questioned from various aspects with the questionnaire. Statistical evaluation of the survey data was conducted for both studies and the results supported each other. Cool light colour and high illuminance ensured that the subjects felt more energetic, alert and rested. On the other hand, neutral coloured light was preferred the most in both studies. Among the illuminance alternatives, 500 lx was assessed as low and 1500 lx as high. The most preferred lighting scenario was the option where 1250 lx illumination is provided with neutral coloured light. With the results obtained in this research, data for determining the optimum conditions for integrative lighting are presented.

The Effect of Blue Light Source in a Lighting Installations on Human Circadian Rhythms

This article describes effect of the blue light on a human health. This effect is emmiting by electrical devices and has a negative impact on person, even if it does not fall into your eyes. This work consists on comparison study of blue radiation spectrum and impact on human organism. It helps to define permissible level of energy dependence on light radiation. The conception of biological impact connected with melanopsin, which one has rods and cones. For humans, nonvisual biological effects, which can be parameterized by the circadian action factor (CAF), are important for their health and work performance. When we spend a lot of time in front of screens of devices, we are receiving radiation of blue light. The article analyses questions associated with biological exposure to radiation from some light emitting diode and lamp light sources with various radiation spectrum (correlated colour temperature Tcc). The biological exposure concept is connected with melanopsyn containing receptors on the eye retina, signals from which arrive to epiphysis and control concentration of the hormone melatonin in the blood. Circadian rhythms are seen at every level of biology, from single cells to complex behaviors. The timing of every biological function in mammals is governed by the master clock in the suprachiasmatic nuclei (SCN), which has an intrinsic period of slightly longer than 24 hours. The light/dark pattern incident on the retina synchronizes the SCN to the 24-hour local time, coordinating and enabling diverse biological functions to occur at the correct time of day and night for optimum species survival. A wide range of modern maladies, from sleep disorders to cancer, has been linked to light-induced circadian disruption. Light has, however, been defined only in terms of the human visual system, not the circadian system. Light source and systems development should consider the needs of both the visual and non-visual systems. Certain signals are fulfil function of controlling the concentration chromatophorotropic hormone within blood. As a basis for calculation were included photochemical and electrical processes in amphiblestrodes, physiological human parameters, as well as coefficient of circadian efficiency, coefficient of growth-inhibitory activity of melatonin and biological equivalent. The optical information is essential for physiological systems of humans, because it not only provides the visual information but also affects their physical, physiological, and psychological behaviors, in which researchers call the latter “non-visual biological effects of light”. In the evolution of lives on earth, the sun and its spectrum, and the alternation of day and night play an important role in the adaptation of human to the natural environment. As receptors of light, human eyes are deeply influenced by standard light, to which the structure and function of human eyes are developed more accustomed during the long-term daily work.

Study on the Influence of LED Spectrum on the Visual and Nonvisual Effects in the Interior Zone of Tunnels

Judicious use of lamps is of profound significance to improve the internal traffic safety of tunnels. This study evaluated the biological effects of spectrum on human visual and nonvisual under mesopic vision category. According to the difference of human eyes’ response to the visual and nonvisual biological effects of different wavelengths of light radiation, a method of applying the mesopic visual spectral luminous efficiency curve to the assessment of nonvisual biological effects and blue light hazards is proposed. The results show that, in theory, under mesopic vision category, the spectrum with high correlation color temperature (CCT) and high color rendering index (CRI) has higher blue light content Z-value and has greater impact on human nonvisual effects and blue light radiation damage, but it can also provide higher human perception luminance. The visual effect detection experiment of driving in the interior zones of the tunnel is simulated in the laboratory, and the critical flicker frequency and reaction time are taken as physiological indexes. The results show that the spectrum with high CCT and high CRI corresponds to lower critical flicker frequency drop value and faster reaction time, which has a positive effect on improving driving safety. Therefore, this paper suggests that the LED with high CCT and high CRI (CCT = 6500 K, CRI2012 = 95) should be used in the interior zones of the tunnel with relatively short lighting section, and the CCT and CRI should be appropriately reduced in other road environments with long lighting section to reduce the impact of spectrum on nonvisual photobiology, so as to improve road traffic safety.

Phosphor-free, color-mixed, and efficient illuminant: Multi-chip packaged LEDs for optimizing blue light hazard and non-visual biological effects

Currently many evaluation models on the photobiological effects (PBE) of light sources do not consider the influence of age and luminance on the pupil diameter, which affects the light radiation intensity on the human retina. In this study, the pupil diameter is taken into consideration when evaluating the PBE of several light sources. Moreover, the correction factor M is proposed. The blue light hazard (BLH) efficacy and the circadian rhythm (CR) effects of the daylight at dusk, together with three indoor light sources with a correlated color temperature (CCT) of about 3000 K were evaluated by using a corrected evaluation model. The results show that an incandescent lamp is more photobiologically friendly for humans, despite being inefficient. Based on high wall-plug efficiency (WPE) GaN-based yellow (565 nm, 24.3%@20 A/cm2) and green (522 nm, 41.3%@20 A/cm2) LEDs on silicon substrate, incandescent-like spectrum and phosphor-free color-mixed white LEDs (CM-LEDs) with a general color rendering index (CRI) of 94, a CCT of 2866 K, and an efficiency of 131 lm/W were manufactured by mixing blue, cyan, green, yellow and red LEDs. The PBE evaluation results of such CM-LEDs are superior to those of an incandescent lamp. Moreover, blue light free and candlelight-toned LEDs with an efficiency of 120.3 lm/W, a general CRI of 84, a special CRI R9 of 93.3, and a CCT of 1810 K were fabricated by mixing yellow and red LEDs (R&Y-mixed LEDs). The R&Y-mixed LEDs show no blue light weighted quantities and have a weaker influence on the CR shift. They are photobiologically friendly for humans and suitable for nocturnal indoor and outdoor lighting environments.

DIRECTIONS FOR IMPROVEMENT OF STANDARDS ON LED TECHNIQUE AND LIGHTING WITH ITS USE

One of the main tasks of high-quality lighting is to provide comfortable visual work and adequate perception of illuminated objects by obtaining light with a wide range of correlated color temperatures with high color rendering quality. The paper analyzes the shortcomings of national regulatory documents on establishing tolerances for the color of lamps and fixtures using LEDs and evaluating their quality in color reproduction. Instead of using Mac Adam ellipses on the SIE 1931 (x, y) color chart for establishing the color requirements it is recommended to use circles on the 1976 SIE (u ', v'), and evaluate the color rendering quality using the CRI method, additionally apply the CQS and TM 30-18 methods. Due to the fact that the spatial color of LED luminaires can be inhomogeneous, it is recommended to indicate both the average color and color in a certain direction, as well as an indicator of the color heterogeneity. The necessity of developing standards for protection against unwanted non-visual biological effects, as well as other negative effects of artificial light, in particular, excessive brightness, pulsation of the light flux, photobiological hazards, etc., is substantiated. Considering the importance of the influence of light pulsation on the quality of lighting, before the development of CIE or IEC standards, it is recommended that national standards for LED lamps and luminaires include the requirements for description of pulsation parameters and measurement methods in accordance with the recommendations of IEEE 1789-2015 standard, which is the most advanced today. For the design of ergonomic lighting, it is proposed to provide information on lamps and luminaires related to their maximum brightness. When developing new criteria for lighting, taking into account the visual impact, it is already possible to use the knowledge accumulated by this time, in particular, for creation of biologically active and biologically dimmed light by changing the spectral composition of radiation and illumination. Proposals related to the limits of the correlated colour temperature, brightness, level of pulsation for lighting of children and educational institutions, residential premises and the like are also considered. Recommendations on the development of new national standards of Ukraine harmonized with international ones are also provided. Keywords: сolor rendering index, percent flicker, correlated colour temperature, illumination, photobiological safety

Topics Important for the up-to-date Interior Lighting Professional

To avoid disappointments with LED lighting installations, detailed knowledge of the typical characteristics of the many different solid-state light sources is essential, while already long-available information on vision and colour seeing has to be combined with entirely new fundamental research on the relationship between lighting on the one hand and vision, performance, comfort, health and well-being on the other hand. Lighting has apart from visual effects also far-reaching non-visual biological effects. These effects influence the way our body “operates” and therefore, influence our health, well-being and alertness. Interior lighting installations today have to be designed so that they provide both suitable visual and non-visual biological effects, while adverse effects of lighting, like flicker, blue light hazard and disruption of the biological clock, are avoided. LEDs offer the possibility to use them not only for lighting but also for data transmission. The use of LED lighting as a means for data communication is referred to as “light beyond illumination”. Visible Light Communication (VLC), LiFi, and light itself used as sensor are part of this subject. The modern lighting professional has to get familiarised with these new technologies and applications. The author of this article published in 2019 the book “Interior Lighting, fundamentals, technology and application” with Springer [1]. It discusses in 500 pages all topics important for the up-to-date interior lighting professional. The present overview article is entirely based on this book and follows the same chapter structure. Each chapter also describes, as an example, one or two crucial aspects in more detail.

Spectral Optimization of Three-Primary LEDs by Considering the Circadian Action Factor

For humans, nonvisual biological effects, which can be parameterized by the circadian action factor (CAF), are important for their health and work performance. In this paper, an approach by adjusting electrical currents of three-primary light-emitting diodes (RGB-LEDs) to tune the CAF and color coordinates to be close to those of the standard light with various correlated color temperature (CCT) (2700 K-6500 K) has been reported. This approach is based on deriving an empirical formula between the optical power and the electrical current. In order to meet the requirement of both high color rendering index (CRI) and better CAF, we theoretically perform further spectral optimization on RGB-LEDs and have found that peak wavelengths of 466, 547, and 615 nm for the blue, green, and red color component, respectively, turn out to be the best peak wavelength combination for obtaining both high CRI and high luminous efficacy of radiation of RGB-LEDs, while the CAF, CCT, and color coordinates of RGB-LEDs approach those of the standard light.

Application-dependent spectrum optimization of four-package LEDs

This paper studies spectrum optimization of four-package LEDs to improve performance of light sources with respect to properties such as luminous efficacy and colour rendering as well as luminous efficacy of radiation under photopic and mesopic conditions and circadian efficacy of radiation for non-visual biological effects. For colour mixing of four-package LEDs, the proportion of each LED in the package follows a linear relationship as does luminous efficacy. For optimization of luminous efficacy of radiation and circadian efficacy of radiation, an inverse proportion function model is proposed. An example of spectrum optimization for a four-package LED shows that by using the proposed model, high performance can be achieved with different weighting coefficients for different applications.

低照度LED光下人眼瞳孔的非视觉生物效应

低照度LED光下人眼瞳孔的非视觉生物效应

低照度LED光下人眼瞳孔的非视觉生物效应

低照度LED光下人眼瞳孔的非视觉生物效应

Ambulant recording of light for vision and non-visual biological effects

Data on the exposure of the human eye to light are essential for investigation into the interaction of light with man. According to present knowledge, two different spectral sensitivities of the visible irradiance are relevant: (1) the spectral luminous efficiency function for vision and (2) the action spectrum for melatonin suppression, also used for other non-visual biological effects. We developed a device called LuxBlick to measure and record both quantities. It consists of two light sensors that are fixed on the wearer’s head, and a control unit and data recording mini-computer worn in a bag around the waist. Real-time data are accessible to those wearing the device. Suitable to be worn in everyday life, the parts at the head are of low mass at the head and inconspicuous.