A light-mixing module consisting of a compound parabolic concentrator (CPC) and a light-mixing tube is proposed herein to realize a uniform and efficient solar-lighting system. In this lighting system, the sunlight collected into a fiber and then guided to an indoor destination is the principal light source, while an auxiliary light source including multiple red, green, blue, and white (RGBW) light-emitting diodes (LEDs) is controlled by an auto-compensating module. To mix the principal and the auxiliary sources and to realize the uniform illumination, the light-mixing tube was coated with BaSO4 and optimized as a cylindrical tube. The design of the light-mixing tube is described and discussed in this article. According to the simulated results, the uniformity and the optical efficiency of the designed light-mixing tube are 82.9% and 85.7%, respectively, while from the experimental results, the uniformity of 85.9% and the optical efficiency of 83.3% have been obtained. In terms of the common indoor-lighting standards and the specifications of commercial components used in lighting systems, the proposed light-mixing module has demonstrated the high uniformity and acceptable optical efficiency. Additionally, since the main components of the light-mixing module can be designed as plastic optics, a cost-effective light-mixing module and a profitable lighting system can be realized. Thus, the performance and the price of the proposed light-mixing module fit the demands of the illumination market, while the proposed system shows the potential for indoor solar-lighting applications.

References

References
1.
Boscarino
,
G.
, and
Moallem
,
M.
,
2016
, “
Daylighting Control and Simulation for LED-Based Energy-Efficient Lighting Systems
,”
IEEE Trans. Ind. Inf.
,
12
(
1
), pp.
301
309
.
2.
Yoo
,
S.
,
Kim
,
J.
,
Jang
,
C. Y.
, and
Jeong
,
H.
,
2014
,”
A Sensor-Less LED Dimming System Based on Daylight Harvesting With BIPV Systems
,”
Opt. Express
,
22
(S1), pp.
A132
A143
.
3.
Tsuei
,
C. H.
,
Sun
,
W. S.
, and
Kuo
,
C. C.
,
2010
, “
Hybrid Sunlight/LED Illumination and Renewable Solar Energy Saving Concepts for Indoor Lighting
,”
Opt. Express
,
18
( S4), pp.
A640
A653
.
4.
Ge
,
A.
,
Cai
,
J.
,
Li
,
L.
,
Wang
,
W.
, and
Qiu
,
P.
,
2012
, “
Panel-Integration of Natural Light and the Related System of Light Guiding and Illumination
,”
Opt. Lett.
,
37
(
17
), pp.
3666
3668
.
5.
Ullah
,
I.
, and
Shin
,
S.
,
2014
, “
Highly Concentrated Optical Fiber-Based Daylighting Systems for Multi-Floor Office Buildings
,”
Energy Build.
,
72
, pp.
246
261
.
6.
Tsuei
,
C. H.
, and
Sun
,
W. S.
,
2011
, “
Momentary Adjusting Methods for Simulating the Color Temperature, Hues and Brightness of Daylight Illumination With RGB LEDs for Indoor Lighting
,”
Opt. Express
,
19
(S4), pp.
A908
A913
.
7.
Vu
,
N. H.
, and
Shi
,
S.
,
2016
, “
Optical Fiber Daylighting System Combined With LED Lighting and CPV Based on Stepped Thickness Waveguide for Indoor Lighting
,”
J. Opt. Soc. Korea
,
20
(
4
), pp.
488
499
.
8.
Ullah
,
I.
, and
Shi
,
S.
,
2012
, “
Development of Optical Fiber-Based Daylighting System With Uniform Illumination
,”
J. Opt. Soc. Korea
,
16
(
3
), pp.
247
255
.
9.
Hsu
,
W. F.
,
Hsu
,
Y. C.
, and
Shen
,
Y. T.
,
2013
, “
Orthogonal Incidence Method for Efficient Sunlight Collection From Asymmetric Light Couplers in Tree-Structured Light Guiding Systems
,”
Appl. Opt.
,
52
(
25
), pp.
6332
6343
.
10.
Zhu
,
Z. M.
,
Jin
,
X. L.
,
Yang
,
H.
, and
Zhong
,
L. S.
,
2014
, “
Design of Diffuse Reflection Freeform Surface for Uniform Illumination
,”
J. Disp. Technol.
,
10
(
1
), pp.
7
12
.
11.
Wei
,
A. C.
,
Lo
,
S. C.
,
Hung
,
P. F.
,
Lee
,
J. Y.
,
Yeh
,
H. Y.
,
Huang
,
H. C.
, and
Li
,
C. M.
,
2016
, “
Compound Parabolic Concentrator Design for Red, Green, Blue, and White LED Light Mixing
,”
Jpn. J. Appl. Phys.
,
55
, p.
08RF02
.
12.
Sun
,
C. C.
,
Moreno
,
I.
,
Lo
,
Y. C.
,
Chiu
,
B. C.
, and
Chien
,
W. T.
,
2012
, “
Collimating Lamp With Well Color Mixing of Red/Green/Blue LEDs
,”
Opt. Express
,
20
(S1), pp.
A75
A84
.
13.
Zumtobel Group,
2017
,
The Lighting Handbook
,
Zumtobel Group
,
Dornbirn, Austria
, Chap. 2.
14.
Dilaura
,
D. L.
,
Houser
,
K. W.
,
Mistrick
,
R. G.
, and
Steffy
,
G. R.
,
2011
,
The Lighting Handbook: Reference and Application
,
Illuminating Engineering Society of North America
,
New York
, Chap. 2.
15.
Song
,
S.
,
Sun
,
Y.
,
Lin
,
Y.
, and
You
,
B.
,
2013
, “
A Facile Fabrication of Light Diffusing Film With LDP/Polyacrylates Composites Coating for Anti-Glare LED Application
,”
Appl. Surf. Sci.
,
273
, pp.
652
660
.
16.
Guo
,
S.
,
Zhou
,
S.
,
Li
,
H.
, and
You
,
B.
,
2015
, “
Light Diffusing Films Fabricated by Strawberry-Like PMMA/SiO2 Composite Microspheres for LED Application
,”
J. Colloid Interface Sci.
,
448
, pp.
123
129
.
17.
Entire Technology,
2010
, “
Diffuser Plate
,” Entire Technology Co., Ltd., Taoyuan, Taiwan, accessed Apr. 5, 2017, http://www.entire.com.tw/english/product1.htm
18.
Taiwan Kangde Xin Composite Material Co,
2017
, “
Diffusion Film
,” Taiwan Kangde Xin Composite Material Co., Ltd., Zhubei, Taiwan, accessed Apr. 5, 2017, http://www.kdxtw.com/products/diffusion-sheet/
19.
ROCOES Electro-optics,
2017
, “
Diffusers (Frost)
,” ROCOES Electro-optics Co., Ltd., Taichung, Taiwan, accessed Apr. 5, 2017, http://rocoes.com.tw/2008e/slight/diffuser.htm
20.
Yongtek,
2017
, “
Pyramid (Prism) Diffuser Sheet
,” Yongtek Co., Ltd., Taoyuan, Taiwan, accessed Apr. 5, 2017, http://www.yongtek.com/diffuser-plate-1p.html
You do not currently have access to this content.