Assessment the Visual Clarity of the Projector in Classroom and Innovative Asymmetric Distribution LED Tube Applications

Abstract

The paper aims to explore the relationship between the vertical plane luminance on projection screens and human visual clarity in the classroom or meeting room. While controlling the lighting environment conditions of the classroom to create different luminous distributions and luminance on the projection screen, a survey is conducted to understand students’ visual experience about screen clarity during the field experiment. The luminance of each picture on the projection screen is measured under the specified lighting conditions of luminaires in the classroom, and the relationship is formulated between the average luminance on the projection screen and the visual satisfaction based on clarity of experience. This will be useful for further studying the acceptable threshold of luminance distribution in the classroom to provide a better visual clarity and lighting quality of projection screens while teaching. In this study, the measurement and performance evaluation on a projection screen were carried out at a classroom in the National Taiwan University of Science and Technology (NTUST). By using an image luminance meter and analyzing the research results, we propose an improvement strategy for asymmetric luminous distribution design of LED light tube and light switch control mechanism of luminaires to resolve the inadequate luminance of the vertical projection screen area to improve the lighting quality and visual clarity of the projection screen while teaching with the least cost.

Permissible viewing times of educational projector and TV

“…To understand the effects of viewing displays or projections on eyes, Kim et al had investigated the suitable luminance range for subjects to read on LCD display under several conditions of ambient lighting through a psychophysical experiment [ 39 ]. Liu et al had discussed the effect of the vertical plane luminance on projection screens and human visual clarity in the classroom to understand the visual satisfaction of students upon viewing the projection [ 40 ]. Nevertheless, little is known regarding the potential threats of those displays on eyes.…”