Open AccessPassive anti-sunlight glare traffic signs with non-axisymmetric freeform lens design
Author(s) -
ShihHsin Ma,
Ting-Jou Ding,
Tsung-Xian Lee,
Yuxiang Lin,
Chen Yy
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.440609
Subject(s) - sunlight , visibility , sign (mathematics) , optics , computer science , glare , lens (geology) , traffic sign , stray light , pixel , rotational symmetry , physics , mathematics , materials science , mathematical analysis , layer (electronics) , mechanics , composite material
This paper proposes a passive optical brightening element design, a non-axisymmetric freeform lens (NAFL), arranged and assembled on a traditional traffic sign. NAFL is the first optical design which can effectively solve the traffic problem that direct sunlight affects the driver's inability to look directly at the traffic sign. The NAFL can converge the sunlight behind the traffic sign and diverge forward to 150 meters away. In this way, the NAFL array combinations on the traffic sign can directly rely on sunlight as image information pixels. According to the simulation, the optical efficiency of the NAFL can be as high as 81.5%. Besides, the angular tolerance is also analyzed to evaluate the working hours of the NAFL. Finally, we made the prototype and proved that such passive brightening components could effectively improve the traffic sign's visibility in harsh sunlight.