The way of city lighting is various. There are two main categories: direct illumination and indirect illumination. The direct lighting is divided into street lighting, contour lighting, point light source lighting, and so on, indirect lighting can be divided into pan lighting, interior lighting, rear projection lighting and other forms of lighting. The following is a brief analysis of the main lighting methods in accordance with the classification.
1 direct lighting
Direct lighting refers to the light emitted by the light source directly into the eyes of the observer or directly illuminate the way the object is illuminated. Direct lighting has outstanding advantages:
C (direct lighting) lighting installation is relatively simple, easy construction. However, this kind of lighting has some disadvantages. A this type of lighting can be directly visible, the impact of lighting and daytime architectural landscape.
B light of this kind of lighting directly into the human eye, in the case of high luminous intensity of the light source, prone to glare, the formation of light pollution, this situation often occurs when the street lamp is not reasonable.
C) direct lighting can not be fully reflected in building materials, lighting strong will cover building material for many outstanding architectural style and material characteristics of the building, the lighting is not desirable; of course, on the other hand, there are many major defects in the building surface of the building, the lighting can be to beautify the modification of certain.
According to the definition of direct lighting and the current people's engineering practice, direct lighting mainly includes street lighting, contour lighting, point light source and surface light source lighting. Below, we make a brief analysis of the characteristics of these lighting methods:
A lighting lighting lighting in the city is currently the most popular and the most important form of lighting. The reasonable setting of street lamp is directly related to the pedestrian traffic, personal safety, social order and so on. Statistical data show. There is no serious shortage of street lights or street lights in urban roads, which are often the areas with high crime rate. In this way, all countries in the world regard the setting of street lamp as an important index to evaluate a city's economy and civilization. With the continuous development of the domestic economy, the domestic small and medium-sized cities have the "no street lights, lights do not light" as a key task to grasp, and has achieved good social and economic benefits. However, there are many problems in the development of urban road lighting, as well as planning management and technology:
A) due to the lack of strong technical support, set the lights completely rely on the experience and the lack of the necessary illumination calculation, resulting in road illumination is too high or too low, when the surface illumination is too high, on the one hand, the formation of light pollution is serious, affecting the driver, on the other hand also caused a great waste of energy.
B) due to improper selection of lamps and the lamp post design is unreasonable, cause lamp side light leakage increases greatly, have a strong glare on pedestrians and vehicles.
When the enclosed street lamp is set on both sides of the highway, because of the high speed, the lamp bar blocks people's sight, which affects people's view of the scenery outside the window of the car. D, due to the lack of the necessary illumination calculation, resulting in uneven illumination of the road surface, increasing the driver's fatigue, affecting traffic safety.
Most of these problems can be solved by means of strengthening the technical force and making reasonable planning and design.
B contour lighting contour lighting is a very rapid development of lighting. With the continuous appearance and improvement of the new linear light source (such as cold tube, side emitting optical fiber, LED neon lamp, etc.), contour lighting becomes more and more colorful. Outline lighting has some outstanding advantages:
At the same time, there are some obvious shortcomings of contour lighting:
B this kind of lighting is difficult to represent the surface of the building material.
C point light source illumination
The point light source referred to here refers to a kind of light source which is similar to the incandescent lamp. Incandescent lamps, LED lamps and other lighting effects can be called a single point light source lighting. Surface light source illumination is a kind of special combination lighting method of point light source illumination. The surface light source is usually formed by a dense combination of a point source or a line source. In addition to the advantages of direct lighting, the two types of lighting, there are some prominent features:
A) combination of various forms. Point (plane) lighting can not only form in building surface (surface) light source array, but also different patterns according to the needs of users to form a variety of different colors, and to facilitate the use of computer control transform all kinds of tricks, performance is very rich.
B (point) (surface) light source lighting can be used in a variety of occasions. These two kinds of lighting can be flexibly applied in all kinds of construction conditions. With the continuous development of science and technology, there has been a new surface light source which can be easily pasted on the surface of glass curtain wall. Glass curtain wall lighting decorative lighting will be a big step forward.
C (point) (surface) lighting costs are easy to control. Under normal conditions, point (surface) light source in the form of array lighting. According to the budget, flexible adjustment of the array spacing to meet the needs of users.
D (point) (surface) light source is usually installed on the exterior walls of buildings. Under the condition of proper control of the brightness of the light source, the two forms of illumination can avoid the disturbance of the normal life of the residents.
On the other hand, these two lighting methods also have the disadvantages of direct lighting, in the brightness of the lamp power control is not exactly the time, prone to glare, affecting the lives of residents.
2 indirect lighting
Indirect lighting is relative to the general name of a kind of direct lighting lighting way, generally refers to the light emitted by the lamp is not directly into the eye, but the first lighting form through other medium was observed. Indirect lighting has some outstanding advantages over direct lighting:
B light emitted by the media in the same time, with a large number of media information, so that the characteristics of the media have been fully demonstrated. When the light emitted by the lamp is passing through the medium, the intensity and the direction of the light can be effectively regulated, so that the glare can be conveniently controlled, and the light pollution can be avoided to the greatest extent.
On the other hand, indirect lighting also has some obvious disadvantages:
A) because the light ray emitted by the lighting medium attenuation, compared with direct lighting, to achieve the same brightness under the condition of indirect lighting requirements consumed more energy, energy utilization efficiency is lower than the direct lighting.
B) for poor media, indirect lighting effect is poor.
According to the definition of indirect lighting and the engineering practice of the people, indirect lighting mainly includes the methods of flood light, inner light transmission and rear projection illumination. Here we have a simple analysis of these lighting methods:
Flood light is generally used to cast lights and other lighting lamps to light the building, green space, tree surface. There are many forms of floodlight, and with the continuous enrichment and development of lighting engineering practice. For example, in the decorative lighting of the bridge, now has developed a floodlight screen form. The lighting can be realized by the combination of a fluorescent lamp, a cold polar tube and a reflecting plate. Floodlight has many outstanding advantages:
A) can fully express the surface material of the building. Flood lighting can not only surface material of all construction of perfect reproduction, and can control the color, color and surface texture of the building cast light angle re shape, achieve the perfect artistic effect. B can easily control the direction of projection and the angle of light, easy to control glare, prevent light pollution.
E (Pan) can be more free to control the ratio of light and shadow, can fully express the space elements of the building.
As a result of the above advantages, the International Commission on illumination (CIE) in the international community to promote the art of flood lighting. And also the preparation of reflective lighting guidance documents. However, flood lighting also has many disadvantages which are hard to overcome:
A, for the construction of the glass curtain wall structure, floodlight is almost powerless. This is due to a low rate of light reflective glass, most easily through the glass into the room, the indoor life form interference; on the other hand, reflective glass of light is directed, not a diffuse light, which is projected onto the glass curtain wall light from a specific direction reflected off the air.
B when the light is not reasonable installation, flood light easily destroy the daytime landscape. Shanghai, the Bund, the night is very charming, but in the daytime but in the beautiful building on the wall to see a black lights, the scenery is quite unsightly.
C) for tall buildings, lighting to light power, increase the electricity costs; on the other hand, light source life decreased sharply with the increase of power source, resulting in the replacement of high maintenance costs.
E) in the pan