From Lighting Design to Lighting Distribution
How does road lighting reflect the design of light distribution, or what kind of light distribution do you need to get better lighting effects? First of all, the lighting design and the light distribution design have always complemented each other.
Lighting design: divided into functional (quantitative) design and artistic (quality) design. Functional lighting design is to determine the lighting level and lighting standards according to the function and activity requirements of the place (illuminance, brightness, glare limit level, color temperature and display Colorimetric) which is used for data processing calculation. On this basis, the lighting design also needs quality design, which can become a catalyst for the atmosphere, can enhance the layering of the decoration, and can be designed according to the response function of the human eye to the illumination. The light environment of the human eye.
Glare: refers to the unsuitable range of brightness in the field of view, extreme brightness contrast in space or time, and even visual phenomena that cause discomfort or reduce visibility. In plain language, it is glare. Glare can cause discomfort, and it can seriously damage the vision. If the driver of the car suffer glare on the road, it is easy to cause a car accident.
Glare is caused by the excessive brightness of a lamp or luminaire directly entering the field of view. The severity of the glare effect depends on the brightness and size of the source, the position of the source within the field of view, the observer's line of sight, the level of illumination, and the reflectance of the room surface. And many other factors, among which the brightness of the light source is the major factor.
Illuminance: If a surface illuminated by light, the luminous flux per unit area is the illuminance of the surface.
Brightness: The ratio of the light intensity in this direction to the area of the light source that the human eye "sees" is defined by the eye as the brightness of the light source unit.
That is to say, the brightness evaluation of road lighting is based on the viewpoint of driving dynamics, and the illuminance is based on a static value.
Background: There is a lack of technical indicators for evaluating the performance of light distribution in the industry. The requirements of optical engineers in the industry for road lighting can only meet the illumination, brightness and glare specified in the Urban Road Lighting Design Standard CJJ 45-2006. The technical parameters are not enough for what kind of light distribution is more suitable for road lighting.
Moreover, this criterion is mainly the norm that road lighting design follows, and the constraints on the design of road lighting design are limited, and the standard is mainly based on the traditional light source, and the binding force of the LED street lighting is relatively low. This is also a headache for companies in the industry and bidding units. In order to promote the standardization of standards, we also need the joint efforts of all of us in the LED lighting industry.
Based on this background, many of our operators can not tell a difference from illuminance and brightness. If you really can't understand it, remember one thing: illuminance is an objective quantity, and brightness is subjective, related to the position of the human eye, this subjective Quantity is the key factor in our direct perception of lighting effects.
Conclusion:
(1) When designing the light distribution of LED lamps, pay attention to brightness, and properly take into account the illumination, so that the road lighting design effect is better, and it is more in line with the road safety and comfort conditions;
(2) If you can only choose the same as the road lighting evaluation index, then choose the brightness;
(3) For those light distributions with uneven illumination and brightness, the illumination and the coefficient method cannot be used to determine the illumination.