LED Lighting - Technology and Perception

Prof. Tran Quoc Khanh is University Professor and Head of the Laboratory of Lighting Technology at the Technische Universitat Darmstadt in Darmstadt, Germany. He graduated in Optical Technologies from the Technische Universitat Ilmenau. He obtained his PhD degree in Lighting Engineering from the same University. He obtained his Degree of Lecture Qualification (Habilitation) from the same University for his thesis in Colorimetry and Color Image Processing. He gathered industrial experience as a project manager by ARRI CineTechnik in Munchen (Germany). He has been the organizer of the well-known series of international symposia for automotive lighting (ISAL) in Darmstadt and a member of several Technical Committees of the International Commission of Illumination (CIE). Dr. Peter Bodrogi is Senior Research Fellow at the Laboratory of Lighting Technology of the Technische Universitat Darmstadt in Darmstadt, Germany. He graduated in Physics from the Lorand Eotvos University of Budapest (Hungary). He obtained his PhD degree in Information Technology from the University of Pannonia in Veszprem, Hungary. He obtained his Degree of Lecture Qualification (Habilitation) from the Technische Universitat Darmstadt in 2010 for his thesis on the optimization of modern visual technologies. He co-authored numerous scientific publications and invented patents about color vision and self-luminous display technology. He has been member of several Technical Committees of the International Commission of Illumination (CIE). Chapter authors: Andreas Groh, Stefan Bruckner, Quang Trinh Vinh and Dmitrij Polin, Laboratory of Lighting Technology of Darmstadt Technical University, Germany. Dr. Holger Winkler, Merck KGaA in Darmstadt, Germany. Dr. Holger Sprute, Lead Engineer Licht & Sicht, Bertrandt AG in Darmstadt, Germany.

Foreword V Table of the Coauthors XIX Preface XXI 1 Introduction 1 Peter Bodrogi and Tran Quoc Khanh 2 The Human Visual System and Its Modeling for Lighting Engineering 7 Peter Bodrogi and Tran Quoc Khanh 2.1 Visual System Basics 7 2.2 Radiometry and Photometry 16 2.3 Colorimetry and Color Science 22 2.4 LED Specific Spectral and Colorimetric Quantities 41 2.5 Circadian Effect of Electromagnetic Radiation 44 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 3.3 Color Semiconductor LEDs 67 3.4 Phosphor Systems and White Phosphor-Converted LEDs 72 3.5 Green and Red Phosphor-Converted LEDs 109 3.6 Optimization of LED Chip-Packaging Technology 118 4 Measurement and Modeling of the LED Light Source 133 Quang Trinh Vinh, Tran Quoc Khanh, Hristo Ganev, and MaxWagner 4.1 LED Radiometry, Photometry, and Colorimetry 133 4.2 Thermal and Electric Behavior of Color Semiconductor LEDs 143 4.3 Thermal and Electric Behavior of White Phosphor-Converted LEDs 149 4.4 Consequences for LED Selection Under Real Operation Conditions 157 4.5 LED Electrical Model 160 4.6 LED Spectral Model 167 4.7 Thermal Relationships and Thermal LED Models 181 4.8 Measurement Methods to Determine theThermal Characteristics of LED Devices 190 4.9 Thermal and Optical Behavior of Blue LEDs, Silicon Systems, and Phosphor Systems 197 4.10 Aging Behavior of High-Power LED Components 201 4.11 Lifetime Extrapolation 214 4.12 LED Dimming Behavior 222 5 Photopic Perceptual Aspects of LED Lighting 233 Peter Bodrogi, Tran Quoc Khanh, and Dmitrij Polin 5.1 Introduction to the Different Aspects of Light and Color Quality 233 5.2 Color Rendering Indices: CRI, CRI2012 242 5.3 Semantic Interpretation of Color Differences and Color Rendering Indices 253 5.4 Object Specific Color Rendering Indices of CurrentWhite LED Light Sources 261 5.5 Color Preference Assessment: Comparisons Between CRI, CRI2012, and CQS 273 5.6 Brightness, Chromatic Lightness, and Color Rendering of White LEDs 285 5.7 White Point Characteristics of LED Lighting 292 5.8 Chromaticity Binning of White LEDs 298 5.9 Visual Experiments (Real Field Tests) on the Color Quality of White LEDs 309 5.10 Circadian Stimulus, Color Temperature, and Color Rendering of White LEDs 315 5.11 Flicker and Stroboscopic Perception of White LEDs under Photopic Conditions 321 6 Mesopic Perceptual Aspects of LED Lighting 337 Tran Quoc Khanh, Peter Bodrogi, Stefan Bruckner, Nils Haferkemper, and Christoph Schiller 6.1 Foundations and Models of Mesopic Brightness and Visual Performance 337 6.2 Mesopic Brightness under LED Based and Conventional Automotive Front Lighting Light Sources 347 6.3 Mesopic Visual Performance under LED Lighting Conditions 353 6.4 Visual Acuity in the Mesopic Range with Conventional Light Sources and White LEDs 357 6.5 Detection and Conspicuity of Road Markings in the Mesopic Range 362 6.6 Glare under Mesopic Conditions 368 6.7 Bead String Artifact of PWMControlled LED Rear Lights at Different Frequencies 388 6.8 Summarizing Remarks to Chapter 6 394 7 Optimization and Characterization of LED Luminaires for Indoor Lighting 399 Quang Trinh Vinh and Tran Quoc Khanh 7.1 Indoor Lighting Application Fields and Requirements 399 7.2 Basic Aspects of LED-Indoor Luminaire Design 403 7.3 Selection Criteria for LED Components and Units 409 7.4 Application Fields with Higher Color and Lighting Requirements 414 7.5 Principles of LED Radiation Generation with Higher Color Quality and One Correlated Color Temperature 421 7.6 Optimization and Stabilization of Hybrid LED Luminaires with High Color Rendering Index and Variable Correlated Colo