Illuminance and Starting Distance of the Far Field of LED-Array Luminaire Operated at Short Working Distance
A luminaire with a light-emitting diode (LED) array can provide hotspot illumination in a short range. Therefore, a design of a luminaire with the largest central illuminance (LCI) and a high uniformity is warranted. In this paper, we present a study of illuminance variation with respect to the dist...
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doaj-5cce472742c64e189aeee95c37095dd82020-11-25T02:34:28ZengMDPI AGCrystals2073-43522020-05-011036036010.3390/cryst10050360Illuminance and Starting Distance of the Far Field of LED-Array Luminaire Operated at Short Working DistanceChing-Cherng Sun0Yi-Syuan Lin1Tsung-Hsun Yang2Shih-Kang Lin3Xuan-Hao Lee4Chi-Shou Wu5Yeh-Wei Yu6Department of Optics and Photonics, National Central University, Zhong-Li 32001, TaiwanDepartment of Optics and Photonics, National Central University, Zhong-Li 32001, TaiwanDepartment of Optics and Photonics, National Central University, Zhong-Li 32001, TaiwanDepartment of Optics and Photonics, National Central University, Zhong-Li 32001, TaiwanDepartment of Optics and Photonics, National Central University, Zhong-Li 32001, TaiwanDepartment of Optics and Photonics, National Central University, Zhong-Li 32001, TaiwanDepartment of Optics and Photonics, National Central University, Zhong-Li 32001, TaiwanA luminaire with a light-emitting diode (LED) array can provide hotspot illumination in a short range. Therefore, a design of a luminaire with the largest central illuminance (LCI) and a high uniformity is warranted. In this paper, we present a study of illuminance variation with respect to the distance of an illumination target of a luminaire with LED array. The emission property of the luminous intensity is characterized by the cosine power law or the divergent angle of full width at half maximum (FWHM). A real LED module is designed to create the simulation for different luminaire types. The occurrence of the LCI and the far-field region are observed. Our results demonstrate that the LCI distance remains shorter than the starting distance of the far field (SDFF). To simplify the simulation, we propose the replacement of the real LED module with a point or flat-extended source. Such light sources must be equipped with the specific cosine power factor corresponding to the divergent angle of the FWHM of the LED module. These light sources are acceptable for describing illumination characteristics, including the SDFF. Our results may facilitate the design of LED-array luminaires operated at short working distances, such as reading lighting or illumination in microscopes.https://www.mdpi.com/2073-4352/10/5/360LED arrayoptical designshort working distancefar field |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Ching-Cherng Sun Yi-Syuan Lin Tsung-Hsun Yang Shih-Kang Lin Xuan-Hao Lee Chi-Shou Wu Yeh-Wei Yu |
spellingShingle |
Ching-Cherng Sun Yi-Syuan Lin Tsung-Hsun Yang Shih-Kang Lin Xuan-Hao Lee Chi-Shou Wu Yeh-Wei Yu Illuminance and Starting Distance of the Far Field of LED-Array Luminaire Operated at Short Working Distance Crystals LED array optical design short working distance far field |
author_facet |
Ching-Cherng Sun Yi-Syuan Lin Tsung-Hsun Yang Shih-Kang Lin Xuan-Hao Lee Chi-Shou Wu Yeh-Wei Yu |
author_sort |
Ching-Cherng Sun |
title |
Illuminance and Starting Distance of the Far Field of LED-Array Luminaire Operated at Short Working Distance |
title_short |
Illuminance and Starting Distance of the Far Field of LED-Array Luminaire Operated at Short Working Distance |
title_full |
Illuminance and Starting Distance of the Far Field of LED-Array Luminaire Operated at Short Working Distance |
title_fullStr |
Illuminance and Starting Distance of the Far Field of LED-Array Luminaire Operated at Short Working Distance |
title_full_unstemmed |
Illuminance and Starting Distance of the Far Field of LED-Array Luminaire Operated at Short Working Distance |
title_sort |
illuminance and starting distance of the far field of led-array luminaire operated at short working distance |
publisher |
MDPI AG |
series |
Crystals |
issn |
2073-4352 |
publishDate |
2020-05-01 |
description |
A luminaire with a light-emitting diode (LED) array can provide hotspot illumination in a short range. Therefore, a design of a luminaire with the largest central illuminance (LCI) and a high uniformity is warranted. In this paper, we present a study of illuminance variation with respect to the distance of an illumination target of a luminaire with LED array. The emission property of the luminous intensity is characterized by the cosine power law or the divergent angle of full width at half maximum (FWHM). A real LED module is designed to create the simulation for different luminaire types. The occurrence of the LCI and the far-field region are observed. Our results demonstrate that the LCI distance remains shorter than the starting distance of the far field (SDFF). To simplify the simulation, we propose the replacement of the real LED module with a point or flat-extended source. Such light sources must be equipped with the specific cosine power factor corresponding to the divergent angle of the FWHM of the LED module. These light sources are acceptable for describing illumination characteristics, including the SDFF. Our results may facilitate the design of LED-array luminaires operated at short working distances, such as reading lighting or illumination in microscopes. |
topic |
LED array optical design short working distance far field |
url |
https://www.mdpi.com/2073-4352/10/5/360 |
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