Outdoor advertising, also known as outdoor advertising, has become more and more popular with its unique intuitiveness and durability, and has been rapidly developed. However, due to the lack of unified planning and lighting standards for outdoor advertising, it is not only chaotic, but also glare and light pollution. In order for outdoor advertising to play a role in guiding consumption, activating the economy, creating an atmosphere and beautifying the city, it is necessary to conduct outdoor advertising lighting standards research.
2 Ambient brightness measurement Outdoor advertising lighting or the sky as the background, or the construction (structure), green, mountain, etc. as the background. Therefore, in order to reasonably determine the outdoor advertising lighting standards, it is necessary to first measure the sky brightness and the surface brightness of the ground objects, especially the building 2.1 measuring method using floodlighting. Since the ambient brightness of different areas is different, it is necessary to test differently. The brightness of the outdoor environment in the area at night. According to actual measurements, the environmental brightness of important transportation hubs and commercial center areas is much higher than that of industrial areas, residential office areas and park green areas; and even in the same area, different outdoor lighting conditions and different illuminations The light reflection on the surface and the difference in the brightness of the outdoor environment are also large. In addition, the brightness of the outdoor environment also changes with time, and the lighting rate of the holiday night lighting is much larger than usual, so the ambient brightness of the holidays is also larger than usual.
For outdoor advertising that needs to be overlooked, it is also necessary to consider that outdoor advertising lighting is affected by the atmospheric attenuation of light. Therefore, the weather that often occurs in the area should be selected for night outdoor ambient brightness test. And when testing the outdoor ambient brightness at night, you must choose a representative time and place.
When conducting the ambient brightness test, you should pay attention to the reasonable choice of the field of view of the brightness meter. Generally speaking, it should be based on the brightness of the large surface of the measured object. Small, relative position, surface optical properties of the object to be measured, and brightness uniformity, etc., select 0.2* or 2* field of view for brightness measurement. That is, in the region where the viewing probability is the greatest, the observer should use 0.21 field of view angle to measure the brightness when the observer is far away from the measured object; otherwise, the brightness is measured by the field of view angle.
When measuring the brightness of the sky, the observer is on the road next to the high-rise building, especially when the building is illuminated by the night scene, which not only makes the measured sky brightness inaccurate, but also makes the measurement with 0.2* or 21 field of view. The brightness of the sky varies greatly, or the observer will stand in the vicinity of the street light pole to measure the above situation. Therefore, the measurement of the sky brightness should also pay attention to the influence of the position of the observer. In order to make the measured sky brightness value more reflect the objective actual situation, the sky brightness should be measured on the city's commanding heights (such as the top of the urban high-rise building) around the unobstructed influence.
Under the above test conditions, on the evening of February 24, 2002, the brightness of the facades of the buildings in the representative commercial districts of Chongqing and the streets of residential and office areas were tested. The test results are shown in Table 1. Shown.
It can be seen from Table 1 that due to the fact that in the night lighting planning, the building (structure) of the building on both sides of the street in the night of Chongqing is measured at the brightness of the building (cfm2). The ambient brightness is classified into the residential area and the office wall. Floodlighting is only near street lighting. There is no outdoor lighting. Table 2 Chongqing City Holiday Night Ambient Ambient Test Average Test Object Test Situation Background Brightness (cd/m2) Remarks Sky Downtown Commercial Street 0. 42 Jiefang Tablet Area No Street Light Alley District Commercial Street 0.10 Shapingba Chongqing Grand Hotel on the top of the street wall with floodlights 28 is a bright background. Only street lighting 9 is the background brightness. There is no outdoor lighting near the general situation. 3 is a dark background. Table 3 Lighting effects and ambient brightness and According to the maximum brightness ratio of the object, the lighting effect and the environment are slightly emphasized. Emphasis is placed on emphasizing the maximum brightness ratio 1: the ring; the brightness of the environment and the maximum brightness of the object being illuminated. The ratio is 1fcl. If blishftr is the same, the dJ degree gkt is I40cd/m2; ht is like a dark background! The brightness level of the Liangye District is different from the brightness level of the residential and office areas. The standard value of the floodlighting brightness of the building (structure) is larger than the latter; however, there is no near the facade of the building (structure). When outdoor lighting is used, the difference between the two is not too significant.
2.2 Data Processing The type 3 brightness meter tests the ambient brightness of the city during the holiday night in Chongqing, and measures the brightness of a certain place three times in succession, taking the average value as the brightness of the place; the test result of the environmental brightness of Chongqing After finishing, as shown in Table 2.
It can be seen from Table 2 that the brightness of the sky in different areas of the same city is quite different. The Jiefangbei area is the bustling central commercial area of ​​Chongqing, and the brightness above it is larger than the Shapingba commercial area far from the downtown area. About 3 times, that is, the light pollution of the sky is more serious.
It can be seen that when the scale of outdoor lighting is further expanded, the light pollution of the sky above the downtown area of ​​Chongqing will be more serious.
According to the research results of the relationship between the lighting effect and the maximum brightness ratio in foreign countries, if the illuminated object is integrated with the environment, then the lighting effect of the illuminated object needs to be slightly emphasized, and the maximum brightness ratio is 1:3; The illumination effect of the illuminated object is emphasized, the maximum brightness ratio is 1:5; if it is emphasized, the maximum brightness ratio between the ambient brightness and the illuminated object is 1:10. Lighting effect and ambient brightness and the illuminated object The relationship of the maximum brightness ratio is shown in Table 3. In order to separate the outdoor advertising lighting from the ambient brightness, a landscape element with good lighting effect is emphasized, and the ratio of the ambient brightness to the maximum brightness of the advertising screen is 1:10. It can be concluded from Table 2. When the observer is closer to the billboard, the brightness of the larger light box advertisement, the floodlight advertisement, and the logo illumination screen is: when the background is bright, the brightness is taken as 280 cd/m 2 ; when the background brightness is normal, the brightness is taken as 90cd/m2; when dark background, the brightness is taken as 30cd/m2. Because the value given in Table 2 is the average of the ambient brightness, taking into account the difference between the average and the maximum, and the future outdoor lighting scale of Shancheng Chongqing For development and environmental brightness, the above brightness values ​​should be adjusted accordingly. That is, when the viewing distance is relatively close, the brightness standard of the larger light box advertisement, the floodlight advertisement and the logo screen is: when the background is bright, the brightness L is 400 cd/m 2 ; when the background brightness L is 50 cd/m 2 , the specific value is as follows Table 4 shows.
The correction factor K2 should be determined by the measured value; in the case of no more reliable standard value, refer to the correction factor of the corresponding surface condition recommended by the International Commission on Illumination (CIE), as shown in Table 5.
Table 4: When the viewing distance is relatively close, the brightness of the larger light box advertisement, the floodlight advertisement and the logo screen standard background advertisement screen brightness (c4m2) application example bright 4 (1) important transportation hub place generally 140 commercial pedestrian street white veneer brick wall dark 50 general street building light reflection ratio <0. 3 on the solid wall surface 5 advertising screen surface pollution degree correction coefficient advertising screen average light anti-reflection (transparent) shot than the advertising screen cleaning situation classification clean dirty dirty very dirty 0.10 dark Surface material 1.522.5030. 4 medium color surface material 247060.7 light color surface material 3510 Germany a scholar to get the maximum brightness of the advertising screen is 500cd / m2 is more appropriate, the value of Table 4 is less than 500cd / m2, thus Table 4 The standard value of indoor and outdoor advertising lighting is more reasonable.
3 The use of brightness values ​​in outdoor advertising lighting makes the outdoor advertising lighting brightness level more in line with the local actual viewing situation, and also needs to correct the factors that affect the viewing in different situations.
3.1 Light source type correction When the warm color-based advertising screen is illuminated with warm light, and when the cold-colored advertising screen is illuminated with cool light, the light source type correction coefficient 1 is taken as 1; when the light source color and the advertising screen are the main When the hue is inconsistent, the light source type correction coefficient 1 can be about 1.3.
Of course, the light source type correction factor can also be determined by the measured value.
3.2 Surface pollution degree The degree of pollution on the surface of the advertisement is related to the city where the advertisement is located and its location, as well as the local climatic conditions and the maintenance and maintenance of the advertisement screen. Another major factor that affects the visual effect in the advertisement illumination is The attenuation of light by the atmosphere, the influence of water vapor, dust and aerosol on the absorption and scattering of light in the near-atmosphere, so that the attenuation of light in the near-atmosphere occurs at different times, places, weather and seasons. Variety. Therefore, for advertising lighting, the viewing distance of the most common viewing position of the public and the weather with the highest probability of occurrence in the local area should be used as the basis for calculation. According to the study of the situation in Chongqing, when the viewing distance is greater than 200m and the meteorological condition is thin smoke, the attenuation effect of the near-surface atmosphere on light should be considered. The viewing distance correction coefficient K3 is a function of the transmittance TN of the near-atmosphere to light per 1 km and the distance rkm through which the light beam passes, and can be expressed by the following equation: the atmospheric transmittance range per 1 km corresponding to different meteorological conditions can be It is found in foreign materials, and the relationship between the attenuation coefficient of the atmosphere and the meteorological visual range can be listed as shown in Table 6.
Table 6: 1Km atmospheric transmittance range corresponding to different meteorological conditions. Meteorological conditions Good weather, thin smoke, moderate smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke, smoke When it is small, the brightness of the advertisement screen is also corrected by the size of the advertisement screen. According to foreign research results, the advertisement screen size correction coefficient K4 is shown in Table 7.
For the total correction factor, the use brightness of the advertisement illumination is the above expression, in order to ensure the viewing effect of the advertisement illumination during the maintenance period, the use brightness of the advertisement illumination must be equal to the product of the advertisement illumination brightness standard value and the total correction coefficient.
4 calculation method advertising screen brightness standard value L after the light source type, surface pollution degree, viewing distance and advertising screen size correction, it is also necessary to take into account the use of light with http:// lighting, That is, the average brightness value in the maintenance period and can be expressed by the following formula. In the design of advertising lighting, the ignition time is increased, the radiation output of the light source is continuously decreased, the damage rate of the lamp is increased, and the dust and dirt accumulated on the lamp are increased over time, and they all make the lamp light up. At the moment, the amount of light output continues to drop. Therefore, when calculating the illuminance, the influence of various maintenance factors should be considered, that is, the illuminance value is converted from the brightness and then the above-mentioned influencing factors are corrected.
4.1 Lumen maintenance coefficient of the light source Because the rated luminous flux given by the electric light source product is 100h, the lumen maintenance coefficient K5 of the light source for the relative light output of the rated luminous flux will continue to decrease as the lighting time is increased. The lumen maintenance factor of the source depends on the performance of the source itself, so the lumen maintenance coefficients of different sources vary with time.
4.2 Lamp integrity rate As the lamp ignition time increases, the number of complete sets of light sources and their accessories is decreasing, that is, the lamp integrity rate is decreasing. Because in the light box advertisement and the floodlight advertising lighting system, generally, a set of lamps is used for illumination, so the correction of the light integrity rate should be performed when performing the calculation of the advertisement illumination.
4.3 Maintenance status of lamps Due to the difference in the surrounding environment of the lamps, the maintenance factor K7 of the lamps should also be different. The lamp maintenance factor is different from the lumen maintenance factor and the lamp integrity rate of the light source. It is not only necessary to calculate the lamp ignition time, but also to calculate the non-ignition time of the lamp. For the light box lighting system, if the light box is sealed well and scrubbed twice a year, then the maintenance factor of the lamp is 0.7, otherwise it is less than 0.7; for the spotlight advertising, if the place is clean, the light is facing down and If the lamp is scrubbed twice a year, the maintenance factor of the lamp can be 0.6, otherwise it is less than 06. 4.4 The use factor of the spotlight For the advertising of the spotlight, the influence of the utilization factor of the spotlight should be considered, and the use of a spotlight The coefficient U is related to the efficiency of the luminaire, the size of the beam angle of the luminaire, the size of the surface to be illuminated, the relative position between them, and the like. CIE recommends U to take 0.3; but when it is necessary to accurately calculate the advertising lighting, it should be determined by regional luminous flux diagram method.
4.5 Advertising lighting calculation The illuminance calculation value of the light box advertising illumination is calculated by the following formula: The illuminance calculation value of the floodlight advertising lighting is calculated by the following formula: 5 Summary The outdoor advertising lighting brightness standard can be measured and analyzed according to the surrounding environment brightness, and considering The relationship between the lighting effect and the brightness ratio is determined. Reasonable advertising lighting brightness standards can play a role in limiting light pollution over the city, while also allowing outdoor advertising lighting to truly play the role of guiding consumption and beautifying the city.
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