A Study on Energy Saving and Light Pollution of LED Advertising Signs

Lighting advertising signs not only play an important role in outdoor lighting environment in Taiwan, but also become the main factor of energy consumption in urban areas at night. Light-emitting diode (LED) has been gradually used in advertising signs due to its advantages. However, in order to be conspicuous and legible in the daytime, signs that are excessively bright may result in considerable light pollution and energy waste at nighttime. Therefore, this research aims to measure the luminance of LED signs and traditional internally lighted signs, and analyze the light trespass from each signage. Based on the research results, the energy consumption from a LED full color screen is 12 times more than a traditional internally lighted sign per day. Statistically, all kinds of LED signs are much higher than traditional internally lighted signs in the percentage of excessive brightness and average luminance value. As for the light trespass, since the vertical illuminance on facade facing the signs increases with the increase of the sign area or the decrease of the distance between the sign and the facade, the vertical illuminance on facade facing the signs would exceed the limit of CIE even if the luminance of the signs achieves the standard of CIE in terms of the general conditions in Taiwan. This happens to LED full color screens in particular and thus results in considerable obtrusive light. To sum up, in order to reduce unnecessary energy consumption and improve the nighttime lighting quality for outdoor environment, this research recommends the luminance limitation for light dimming of LED advertising signs should refer to the zoning, time period, and sign area.

Factors of Creativity

The dictionary defines a factor as “something that actively contributes to the production of a result.” A number of factors may be attributed to the creative process and its final product. These factors are purpose, diversity, relationships, imagery, and externalization. The ingredients of creativity seem to be the same for diverse domains, from the arts to the sciences and social studies. The factors of creativity are depicted in Figure 4.1. These parameters refer to the purpose of the project, plus four others identified by diversity, relationships, imagery, and externalization. The second and third factors define the structure of the problem and its solution, while the last two relate to representation issues for generating the solution and expressing it in some form. The creative factors are listed in Table 4.1, along with their defining characteristics and prescriptive implications. The operational implications are described for both the human problem solver, as well as for the computer system that might be developed to assist in this task. For example, imagery relates to the development of ideas through sensory mechanisms, whether in actuality or in conception. The prescriptive implication is to generate a series of images in various formats, whether pictorial, auditory, or tactile. Of these, the most powerful vehicle is the visual image which can simultaneously represent numerous objects and their relationships. The operational implication for a computer-based system is a rich store of icons or pictorial images that may be depicted on color screens using versatile graphic techniques. The problem to be resolved defines the purpose of the creative process. The factor of purpose involves the distillation of a problem into its essential elements. This involves the identification of critical attributes and the elimination of extraneous features. For millennia people had yearned to fly. The existence of birds was proof that flight was possible. Man’s straightforward approach to achieving flight was to imitate aviary shapes and motions, especially wings and their flapping. But birds have functional requirements other than airborne motion, such as feeding, fleeing, and reproduction. It was not until the peripheral activities such as wing-flapping were ignored, that man could design a machine allowing him to attain active flight.