LED Lighting: Technology and Perception

517 Pages·2014·9.85 MB·English

by  T.Q. Khan, P. Bodrogi, Q.T. Vinh, H. Winkler

Edited by
Tran Quoc Khanh, Peter Bodrogi,
Quang Trinh Vinh, and HolgerWinkler
LED Lighting
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Edited by
Tran Quoc Khanh, Peter Bodrogi, Quang Trinh Vinh, and
Holger Winkler
LED Lighting
Technology and Perception
Editors All books published by Wiley-VCH are
carefully produced. Nevertheless, authors,
editors, and publisher do not warrant the
Prof. Tran Quoc Khanh
information contained in these books,
Technische Universität Darmstadt
including this book, to be free of errors.
Laboratory of Lighting Technology
Readers are advised to keep in mind that
Darmstadt, Germany
statements, data, illustrations, procedural
details or other items may inadvertently
Dr. Peter Bodrogi
be inaccurate.
Technische Universität Darmstadt
Laboratory of Lighting Technology
Darmstadt, Germany Library of Congress Card No.: applied for
Dr. Quang Trinh Vinh British Library Cataloguing-in-Publication
Technische Universität Darmstadt Data
Laboratory of Lighting Technology A catalogue record for this book is
Darmstadt, Germany available from the British Library.
Dr. Holger Winkler Bibliographic information published by the
Merck KGaA Deutsche Nationalbibliothek
Darmstadt, Germany Te Deutsche Nationalbibliothek
lists this publication in the Deutsche
Nationalbibliografie; detailed
bibliographic data are available on the
Internet at <http://dnb.d-nb.de>.
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V
Foreword
Te lighting industry has been going through a revolution with the phasing out
of the tungsten source and the advance of LED technology. Te latter is well
known for its greater energy efficiency, longer life, and its ability to provide
a more adjustable spectral power distribution, illuminance, and beam shape.
Tese features lead to large changes in lighting applications: LED is now not just
meeting the basic need of illumination, but also moving into the improvement
of work performance, the provision of optimum atmosphere environment, and
the achievement of better health and wellbeing. However, its characteristic of
providing intensive illuminance in small fields leads to some large performance
discrepancies when compared with conventional light sources such as fluorescent
and tungsten. Many of the earlier quality measures cannot be applied to LED
sources and for this reason new standards and guidelines have recently been
developed. So far, there has been no good textbook in illumination engineering
to focus mainly on LED technologies.
Te book covers a comprehensive range of topics on LEDs from the fundamen-
tal sciences of vision, radiometry and photometry, colorimetry, and the circadian
rhythm; followed by the manufacturing techniques of radiation generation and
packaging, the design, and modeling of light sources; then lighting quality mea-
sures under photopic andmesopic regions; and finally, the optimization and char-
acterization of indoor and outdoor lighting.
A reader who is unfamiliar with color science should have no problem to go
through the book, as it gives sufficient background information. Tus the book
will be suitable for beginners as well as for more experienced readers. A number
of topics are focused on the development of new standards by the International
Commission on Illumination (CIE), which is based on recent results of LED light-
ing research and applications. Te book can be considered as the most compre-
hensive and an up-to-date textbook available, which will inject new knowledge for
both color engineers and academic researchers.
My congratulations go to the authors for the great efforts in compiling this
text. Tey include a large number of examples of their research results, and have
demonstrated that the research and teaching go hand in hand.
VI Foreword
I am strongly recommending this textbook as a valuable research and develop-
ment tool.
Ronnier Luo
Professor of Zhejiang University (China),
Leeds University (UK),
National Taiwan University of Science and Technology (ROC),
Director CIE Division 1
VII
Contents
Foreword V
Table of the Coauthors XIX
Preface XXI
1 Introduction 1
Peter Bodrogi and Tran Quoc Khanh
Reference 5
2 The Human Visual System and Its Modeling for Lighting
Engineering 7
Peter Bodrogi and Tran Quoc Khanh
2.1 Visual System Basics 7
2.1.1 TeWay of Visual Information 7
2.1.2 Perception 8
2.1.3 Structure of the Human Eye 8
2.1.4 Te Pupil 9
2.1.5 Accommodation 10
2.1.6 Te Retina 10
2.1.7 Cone Mosaic and Spectral Sensitivities 12
2.1.8 Receptive Fields and Spatial Vision 14
2.2 Radiometry and Photometry 16
2.2.1 Radiant Power (Radiant Flux) and Luminous Flux 18
2.2.2 Irradiance and Illuminance 19
2.2.3 Radiant Intensity and Luminous Intensity 19
2.2.4 Radiance and Luminance 20
2.2.5 Degrees of Efficiency for Electric Light Sources 21
2.3 Colorimetry and Color Science 22
2.3.1 Color Matching Functions and Tristimulus Values 24
2.3.2 Color Appearance, Chromatic Adaptation, Color Spaces, and Color
Appearance Models 27
2.3.2.1 Perceived Attributes of Color Perception 27
2.3.2.2 Chromatic Adaptation 27
VIII Contents
2.3.2.3 CIELAB Color Space 29
2.3.2.4 Te CIECAM02 Color Appearance Model 31
2.3.3 Modeling of Color Difference Perception 36
2.3.3.1 MacAdam Ellipses 36
′ ′
2.3.3.2 u , v Chromaticity Diagram 36
2.3.3.3 CIELAB Color Difference 37
2.3.3.4 CAM02-UCS Uniform Color Space and Color Difference 38
2.3.4 Blackbody Radiators and Phases of Daylight in the x, y Chromaticity
Diagram 39
2.4 LED Specific Spectral and Colorimetric Quantities 41
2.4.1 Peak Wavelength (λ ) 41
P
2.4.2 Spectral Bandwidth at Half Intensity Level (Δλ ) 42
0.5
2.4.3 Centroid Wavelength (λ ) 43
C
2.4.4 Colorimetric Quantities Derived from the Spectral Radiance
Distribution of the LED Light Source 43
2.4.4.1 Dominant Wavelength (λ ) 43
D
2.4.4.2 Colorimetric Purity (p ) 43
C
2.5 Circadian Effect of Electromagnetic Radiation 44
2.5.1 Te Human Circadian Clock 44
References 47
3 LED Components – Principles of Radiation Generation and
Packaging 49
HolgerWinkler, Quang Trinh Vinh, Tran Quoc Khanh, Andreas Benker,
Charlotte Bois, Ralf Petry, and Aleksander Zych
3.1 Introduction to LED Technology 49
3.2 Basic Knowledge on Color Semiconductor LEDs 50
3.2.1 Injection Luminescence 50
3.2.2 Homo-Junction, Hetero-Junction, and QuantumWell 52
3.2.2.1 Homo-Junction 52
3.2.2.2 Hetero-Junction 53
3.2.2.3 QuantumWell 54
3.2.3 Recombination 56
3.2.3.1 Direct and Indirect Recombination 56
3.2.3.2 Radiative and Nonradiative Recombinations andTeir Simple
Teoretical Quantification 57
3.2.4 Efficiency 60
3.2.4.1 Internal Quantum Efficiency (𝜂 ) 60
i
3.2.4.2 Injection Efficiency (𝜂 ) 60
inj
3.2.4.3 Light Extraction Efficiency (𝜂 ) 60
extraction
3.2.4.4 External Quantum Efficiency (𝜂 ) 62
ext
3.2.4.5 Radiant Efficiency (𝜂 , See Section 2.2.5, Eq. (2.13)) 62
e
3.2.4.6 Luminous Efficacy (𝜂 ) 62
v
3.2.5 Semiconductor Material Systems – Efficiency, Possibilities, and
Limits 63