Evaluation of light-emitting diodes for signage applications (original) (raw)
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Evaluation of Visual Performance Using LED Signboards under Different Ambient Conditions
Procedia Engineering, 2012
This research aimed to study how to make the light emitting diode (LED) signboards be more legible under high illuminative conditions and to avoid the observers feeling dazzling glare under low illuminative conditions. This research firstly studied the literatures to explore the drivers' visual ergonomic as well as the optical properties of LED, and investigated the relatively existing norms for engineering vehicle LED signboards. Three variables were set in this study: three kinds of ambient condition, four kinds of luminance contrast and two kinds of character form. In the first phase of the experiment, subjects observed LED signboards in both near and distant locations and filled out the SWN scale (Subjective Well-being under Neuroleptics), and in the second phase, subjects were then asked to moved forward and recorded their perceptions of comfort and glare to distance range. The findings demonstrated that, there was no variation in subjective evaluation to display signs with no backgrounds either in the near or distant locations, while to display signs with backgrounds, the subjects perceptions were the farther the distance, the clearer the legibility; higher ambient illumination could effectively reduce observers' glare perception to LED signboards; signboards with backgrounds at the luminance contrast of 3:1 (L max = 3100, L min = 1033 cd / ㎡) showed the lowest uncomfortable and glare level to observers. The two forms of character showed no significant variation in affecting observers in terms of the comfort and glare perception.
Luminance Requirements for Lighted Signage
Light-emitting diode (LED) technology is presently targeted to displace traditional light sources in backlighted signage. The literature shows that brightness and contrast are perhaps the two most important elements of a sign that determine its attention-getting capabilities and its legibility. Presently, there are no luminance standards for signage, and the practice of developing brighter signs to compete with signs in adjacent businesses is becoming more commonplace. Sign luminances in such cases may far exceed what people usually need for identifying and reading a sign. Furthermore, the practice of higher sign luminance than needed has many negative consequences, including higher energy use and light pollution.
Brief Communication: Impact of Sign Panel Luminance on Visual Comfort
Interdisciplinary Journal of Signage and Wayfinding
Signs should produce useful visual information to road and sidewalk users without creating undue glare or visual distraction. In order to assist in navigation and wayfinding, signs must be sufficiently conspicuous. For this reason their brightnesses are often higher than the surrounding visual environment. However, if the brightness becomes too high, the sign risks contributing to visual discomfort. Several published recommendations for limiting sign brightness include limits on the maximum illuminance from the sign (in lux). There is evidence, however, that the maximum luminance of a light source can also influence visual comfort. To investigate the potential role of maximum luminance, a pilot study was carried out to assess visual responses to sign panels producing the same illuminance but differing in luminance.
Journal of the Society for Information Display, 2017
This study investigated drivers' visual perception of information displayed in LED traffic signs under different levels of environmental luminance. Concerning the information displayed, the environmental luminance comprised four luminance contrasts, two arrow types, and three environmental luminances, which were used to identify the visibility of traffic signs at the reading distance. Regarding visible distance, visibility involved reading starting and end points, extent of glare, comfortable distance, and glare distance. According to the study results obtained by using a highly reliable glare assessment method and studying the LED traffic signs, the lower the luminance contrast of traffic signs was the higher glare the participants perceived. A luminance contrast of 6200:2066 cd/m 2 provided the farthest comfortable and glare distances, enabling drivers to notice the signs comparatively earlier and have sufficient time to react accordingly. Overall, arrow type "<<<" outperformed "←" because the former was easier for drivers to read and created less glare. Regarding environmental luminance, traffic signs displayed in high and medium luminance environments (i.e., extremely sunny and cloudy days, respectively) each featured their own advantage, whereas those displayed in low luminance environments (nights) have to be further improved.
A Study of Vision Ergonomic of LED Display Signs on Different Environment Illuminance
Lecture Notes in Computer Science, 2011
The LED (light emitting diode, also referred to as LED) have already been used widely. However, despite the high visibility of LED with high brightness performance, it also leads to a glare problem, which generates a direct security issue in applying to traffics. Therefore, this research aimed to study how to make the LED display sign be more legible under high illuminative environments and to avoid the observers feeling dazzling glare under low illuminative environments. This research firstly studied the literatures to explore the drivers' visual ergonomic as well as the optical properties of LED, and investigated the relatively existing norms for engineering vehicle LED display signs. Three variables were set in this study: three kinds of ambient illumination, four kinds of luminance contrast and two kinds of character form. In the first phase of the experiment, subjects observed LED display signs in both near and distant locations and filled out the SWN scale (Subjective Well-being under Neuroleptics), and in the second phase, subjects were then asked to moved forward and recorded their perceptions of comfort and glare to distance range. The findings demonstrated that, there was no variation in subjective evaluation to display signs with no backgrounds either in the near or distant locations, while to display signs with backgrounds, the subjects perceptions were the farther the distance, the clearer the legibility; higher ambient illumination could effectively reduce observers' glare perception to LED display signs; display signs with backgrounds at the luminance contrast of 3:1 (L max = 3100, L min = 1033 cd / ㎡) showed the lowest uncomfortable and glare level to observers. The two forms of character showed no significant variation in affecting observers in terms of the comfort and glare perception.
Factors Affecting Sign Visibility, Conspicuity, and Legibility: Review and Annotated Bibliography
Interdisciplinary Journal of Signage and Wayfinding
This paper summarizes published research studies, technical reports and codes and standards related to the visibility (i.e., conspicuity and legibility) of signage. In the summary that follows, publications are grouped and discussed according to several different topics. First, the typographic and symbolic characteristics of signs and the information they carry are described (e.g., letter size, font selection, etc.); second, photometric, colorimetric and temporal properties of signs as they affect visibility; finally, environmental considerations (e.g., daytime versus nighttime viewing, whether a sign is located in a rural or urban area, etc.) as they influence sign design are reviewed. Annotated summaries of each publication in the literature review are included at the end of this paper.
Research on Color Luminance Ratio Design of Architectural Accessible Signs
Proceedings of the 2017 2nd International Conference on Civil, Transportation and Environmental Engineering (ICCTE 2017), 2017
Luminance ratio or contrast is a key indicator for accessible signs' color design. Existing researches had different results due to inadequate consideration of influencing factors. This project designed a subjective evaluation experiment within normal illumination environment, the minimum luminance ratio to identify an architectural accessible sign was statistically analyzed under different hue scheme, sight distance and visual acuity.
Lecture Notes in Computer Science, 2013
In this study, conspicuity and readability of the text on light-emitting diode (LED) information boards were evaluated by psychological experiments, and the influences of color combinations of text / background, luminance, and shadow were evaluated quantitatively. In recent years, LED boards have been able to display full-color images, and they have many functions to highlight text. Therefore, it is assumed that the LED board ability to function may be reduced depending on the way it is used. We investigated the relationship of color combinations of text and background, luminance, and shadow to conspicuity and readability to evaluate ease and efficiency of information communication via the LED board. We found that (1) the size of the area with high luminance affected conspicuity, (2) the difference of luminance of the part adjacent to the text/background affected readability, and (3) shadow affected both conspicuity and readability. Furthermore, trade-off between them was confirmed.
1987
The study objective was to identify a sign-lighting system that has a lower electric power cost and reduced maintenance requirements and that provides adequately for the motorists' needs in terms of legibility and illumination level. Twenty-five candidate lighting systems were identified through a review of technical data and specifications for lamps and fixtures by an independent lighting expert. Photometric tests and computer analyses of sign illumination levels reduced the number of candidates to 10 alternative systems, which were then field tested. Each alternative lighting system was field tested for 10 to 14 months. Sign luminance was measured with a telephotometer. Power consumption was monitored. Maintenance requirements and lamp life were noted. A human factors study determined legibility distance and rated viewing comfort, lighting uniformity, and color rendition. An economic analysis was performed in which the initial cost of acquiring and installing the lighting syst...