Design of asymmetric freeform lens for low glared LED street light with total internal reflection

Lai, Min-Feng; Chen, Yi-Chian; Anh, Nguyen Doan Quoc; Chen, Tsai-Yu; Ma, Hsin-Yi; Lee, Hsiao-Yi

doi:10.1364/oe.24.001409

Cited by 13 publications

(5 citation statements)

References 12 publications

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“…However, like other light sources, LEDs alone cannot provide the necessary intensity distribution in all applications. Therefore, LED lights tend to be furnished with secondary lenses to tailor their light to meet the standards for lighting applications [9,10], such as road lighting.…”

Section: Introductionmentioning

confidence: 99%

Design and Prototyping of Efficient LED Counter Beam Light with Free-Formed Surface for Meeting International Tunnel Lighting Standards

Liao¹,

Chen²,

et al. 2021

Energies

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An LED Counter Beam Light (CBL) with a free surface secondary lens is proposed to enhance the safety and efficiency of tunnels. The secondary lens was designed and produced to be mounted on a 50 W white-light LED array to generate the targeted counter beam pattern, in order to meet the standards for enhanced tunnel road lighting of the CIE (Commission Internationale de l’Eclairage)—CIE 88:2004—in a trial tunnel lighting scheme. Through the simulation of a road tunnel in Northern Taiwan using the LiteStar four-dimensional software, it was shown that the proposed LED light can serve as a qualifying CBL to generate an average road tunnel surface luminance (Lav) of 182.76 cd/m2, which is better than the 138 cd/m2 that commercial High-Pressure Sodium (HPS) tunnel lights can provide and the 181 cd/m2 minimum stipulated in the CIE 88:2004 regulations. The results also show that the proposed LED light accomplishes a contrast revealing coefficient qc of 1.03, which is above the minimum regulatory level of 0.6 for a qualified CBL, as well as a luminance uniformity Uo of 0.89 (regulatory minimum, 0.4), longitudinal luminance uniformity UL of 0.99 (regulatory minimum, 0.6), and glare factor TI (threshold increment) of 7.24% (regulatory minimum, 15%). In order to test the feasibility of the LED CBL for future commercialization, the proposed LED CBL was prototyped and measured; the results demonstrate that an average road surface luminance (Lav) of 184.5 cd/m2, intensity of the luminance uniformity Uo of 0.7, intensity of the longitudinal luminance uniformity UL of 0.94, glare factor of 7.04%, and contrast revealing coefficient qc of 1.38 can be achieved, which are all above the levels required by the CIE 88:2004 regulations.

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Section: Introductionmentioning

confidence: 99%

Design and Prototyping of Efficient LED Counter Beam Light with Free-Formed Surface for Meeting International Tunnel Lighting Standards

Liao¹,

Chen²,

et al. 2021

Energies

Self Cite

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“…Freeform lenses have shown the difference in luminosity intensity distribution in comparison with the single typical LED, hence, the study of freeform optics has been developed for various needs on every scale. For open space lighting, like street lighting, an asymmetric freeform lens for low glared LED street light with total internal reflection [21] and microlens arrays can help in achieving the desired illuminance on the road [22]. On the microscopic scale, LED arrays have also been exploited in the study of phototherapy and many medical purposes [23,24].…”

Section: Introductionmentioning

confidence: 99%

A Simple Designed Lens for Human Centric Lighting Using LEDs

Giang

Tien

et al. 2020

Applied Sciences

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Light is generally important for human beings. Visible light supports vision and can modify circadian rhythm, and together with invisible light at longer or shorter wavelength can also make either a direct or indirect impact on human biological and mental health. For medical applications, several studies have shown success in using light to fasten the skin regeneration in burns and to cure diseases such as newborn jaundice. In daily life, an appropriate amount and time exposure to certain types of light can result in rising of alertness and mood improvement, which leads to noticeable growth in one’s productivity. Therefore, human centric lighting can modify lighting factors to make the best of the natural characteristics of light. The seek an ideal indoor lighting system is widely carried out not only by scientists but also by architects. A qualified luminaire is considered by many factors, including luminous productivity, visual comfort and expenses; meanwhile, the idealization of illuminance is also constructed in many ways, such as widening the lamp’s surface area, changing of luminaire’s positions and applying different methods to illuminate a surface. Approaching these problems, our idea is to study the uplighting method and freeform optics using low-cost acrylic lenses. By changing lens shape and optimizing the factors which affect the illuminance such as the irradiation angle and the distance between the luminaire and the reflection surfaces, we find the most effective lens and its peaks due to each factors using the ray-tracing simulation to obtain results concerning high uniformity of illumination.

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“…Illumination is the deliberate use of light emitted from a source (or multiple sources) to achieve a practical or aesthetic effect, such as indoor lighting, outdoor lighting, automotive lighting, etc . In practical applications, it may require different distributions of light to achieve different lighting effects.…”

Section: Introductionmentioning

confidence: 99%

Design of Freeform Illumination Optics

Feng

Zheng

et al. 2018

Laser & Photonics Reviews

127

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Freeform optics constitutes a new technology that is currently driving substantial changes in illumination design. It liberates designers and engineers from restrictions of optical surface geometry, enabling them to achieve compact, lightweight, and efficient illumination systems with excellent optical performance. Freeform optics is currently used widely for both fundamental research and practical applications. This Review focuses on the design of freeform illumination optics, which is a key factor in advancing the development of illumination engineering. The design methods of freeform illumination optics can be divided into two groups: zero‐étendue algorithms based on ideal source assumption and design algorithms for extended light sources. The zero‐étendue algorithms include ray mapping method, Monge–Ampère equation method, and supporting quadric method. The algorithms for extended sources include illumination optimization, feedback design, and simultaneous multiple surfaces method. The characteristics and limitations of these design methods are illustrated and a summary of these methods with future outlooks is also given.

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Design of asymmetric freeform lens for low glared LED street light with total internal reflection

Cited by 13 publications

References 12 publications

Design and Prototyping of Efficient LED Counter Beam Light with Free-Formed Surface for Meeting International Tunnel Lighting Standards

Design and Prototyping of Efficient LED Counter Beam Light with Free-Formed Surface for Meeting International Tunnel Lighting Standards

A Simple Designed Lens for Human Centric Lighting Using LEDs

Design of Freeform Illumination Optics

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