LCD Backlights (Wiley Series in Display Technology)

✍ Scribed by Shunsuke Kobayashi, Shigeo Mikoshiba, Sungkyoo Lim

• Publisher: Wiley
• Year: 2009
• Tongue: English
• Leaves: 292
• Series: Wiley Series in Display Technology
• Category: Library

✦ Synopsis

Research and development on liquid crystal display (LCD) backlight technologies are becoming increasingly important due to the fast growth of the LCD business. Backlight technologies contribute to functional improvements of LCDs in terms of wide colour reproduction, uniformity improvements of luminance and colour temperature, high luminance, long life, less power consumption, thinner backlight unit, as well as cost. As LCD panel technology progresses, the lighting technology that provides the illumination for the panel must similarly evolve.
LCD Backlights is written by a global panel of leading researchers and practitioners in this field from both academia and industry.  The first part of LCD Backlights details the variety of applications of backlights including those in LCD-TV, PC monitors and mobile devices. The second part is a full examination of the different light sources that are used including the latest technological trends in amongst others, cold cathode fluorescent lamps (CCFLs), mercury-free fluorescent lamps and light emitting diodes (LEDs). The final part of the book analyses the optical component of backlights such as diffusers and brightness enhancement films.
Key features:
Provides a comprehensive analysis of the latest status of LCD backlight research and development.
Discusses the design considerations and technical requirements for the multiple applications of LCD backlights.
Considers techniques used for power saving and picture quality improvement.
Examines the requirements for backlight units used for TVs, PC monitors and mobile phones.
LCD Backlights is of significant interest to practising electronics and display engineers as well as scientists working on the development of liquid crystal displays. This book is also of value to graduate students and researchers involved in display technologies.

✦ Table of Contents

Contents......Page 6
Series
Editor’s Foreword......Page 12
About
the Editors......Page 14
List
of Contributors......Page 16
Preface
......Page 18
Part
One—Backlights by Use......Page 20
1.1 Introduction......Page 22
1.2 Structure of LCD TV Backlights......Page 24
1.3.1 CCFL , EEFL , and HCFL......Page 25
1.3.2 FFL......Page 29
1.3.3 LED......Page 31
1.4.1 Luminance......Page 33
1.4.2 Color Reproducibility......Page 34
1.4.3 Correlated Color Temperature......Page 36
1.4.4 Thermal Management......Page 37
References......Page 38
2.1 Introduction......Page 40
2.2.1 Origin of Motion Blur......Page 41
2.2.2 Picture Quality Evaluation Methods of Moving Images: N BET and MPRT......Page 43
2.3 Methods of Reducing Motion Blur......Page 45
2.4 Backlight Blinking......Page 49
References......Page 51
3.1 Present Status......Page 52
3.2 Technological Impacts......Page 54
3.3.1 Video Input Processing......Page 55
3.3.3 Video Output and Driving of LED s......Page 56
3.3.5 Communication Control......Page 58
3.4 Details of a Six primary color Backlight Unit......Page 59
3.5 Signal Processing of Transforming from Three Primaries to Six Primaries......Page 61
3.6 Color Gamut of the Prototype Monitor......Page 62
3.8 Remaining Issues......Page 64
References......Page 65
4.1 Introduction......Page 68
4.2 Display Method of LCD and Power Reduction......Page 69
4.3 Principle of the Adaptive Dimming Technique......Page 70
4.4.1 A Use of Optical Isolator......Page 72
4.4.2 Comparison of 0 D , 1D and 2 D Dimming......Page 73
4.4.3 Choice of Block Size......Page 76
4.5 Other Features of the Adaptive Dimming Technique......Page 77
References......Page 78
5.1 Introduction......Page 80
5.3 Optical Systems for Backlights......Page 81
5.4 Light Sources for Backlights......Page 83
5.5.1 Lamp Ref ector......Page 84
5.5.2 Light guide Plate......Page 85
References......Page 90
6.1 Introduction......Page 92
6.2.1 Structure of a Backlight with Two Prism Sheets......Page 93
6.2.2 Principles of LED Backlights......Page 95
6.3.1 Light Guides......Page 99
6.3.2 Ref ector Sheets......Page 100
6.4 Various LED Backlight Conf gurations......Page 101
6.4.1 Reverse Prism Conf guration......Page 102
6.4.2 Point Light Source Conf guration......Page 103
References......Page 106
Part
Two—Light Source Devices......Page 108
7.2.1 Basic Structure......Page 110
7.2.2 Operating Principle......Page 111
7.3.1 Electrical Properties......Page 112
7.3.2 Optical Properties......Page 114
7.3.3 Lamp Life......Page 116
7.4.3 Higher Luminance......Page 118
7.4.4 Higher Luminous Eff cacy......Page 119
7.5 Conclusions......Page 120
8.2 Various Drive Schemes of CCFL Inverters......Page 122
8.3 Equivalent Circuit of CCFL s......Page 125
8.4 Inverter Circuits......Page 127
8.5 Driving of CCFL s with Inverters......Page 129
8.6 Lamp Current Balancers for Driving Multiple Lamps......Page 130
References......Page 134
9.1 HCFL Light Source as a Member of the Fluorescent Lamp Family......Page 135
9.2 Introduction of the Hot Cathode in Fluorescent Lamps......Page 137
9.3 Driving the HCFL......Page 138
9.4 Cathode Life Properties of HCFL......Page 140
9.6 Designing a Backlight with HCFL......Page 141
9.8 The Dimming Feature......Page 144
References......Page 146
10.1 Introduction......Page 148
10.2.1 Lamp Structure......Page 149
10.2.2 Discharge Characteristics......Page 150
10.2.3 Energy Balance of EEFL s......Page 153
10.2.4 Lifetime......Page 154
10.3.1 Power Consumption......Page 155
10.3.3 Pinhole Formation......Page 156
10.4.1 Driving of EEFL Backlights......Page 157
10.4.2 Luminance and Eff cacy......Page 158
10.4.4 Color Gamut......Page 160
10.5.1 Long EEFL s for Large LC TV s......Page 161
10.5.2 Noncircular Cross Section EEFL......Page 162
10.6 Conclusions......Page 163
References......Page 164
11.2 The History of FFL Development......Page 166
11.2.2 Generation 2 FFL s (Glass forming)......Page 168
11.2.4 Generation 4 FFL s (Tipless)......Page 169
11.3 Characteristics of FFL s......Page 170
11.3.3 The Fabrication Process......Page 171
11.4.1 High Luminous Eff ciency and Luminance......Page 173
11.4.2 Long Life......Page 174
References......Page 177
12.1 Introduction......Page 178
12.2.3 Microwave Discharge......Page 179
12.4 Features of Electrodeless Lamps......Page 181
12.5.2 Inner Coil Lamp......Page 182
12.5.3 Toroidal Winding Lamp......Page 185
12.7 Application to LCD Backlights......Page 186
12.8 Conclusions......Page 187
References......Page 188
13.1 Introduction......Page 190
13.3 Basic Characteristics of Xenon Discharge......Page 191
13.4.1 Cylindrical Discharge Type......Page 193
13.4.2 Micro discharge Type......Page 194
13.5.1 Flat Discharge......Page 195
13.5.2 Structure and Driving of Lamp......Page 196
13.5.3 Comparison of Hg and Xe Discharges......Page 197
References......Page 198
14.1 Introduction......Page 200
14.2 LED Device Principle......Page 201
14.2.2 Requirements for BLU Systems......Page 202
14.2.3 Two Generic Designs of LED Components......Page 203
14.2.5 Multiple Benef ts......Page 204
14.3.2 Example of an Indirect LED Backlighting for a 19 inch LCD Monitor......Page 205
14.3.3 The Results......Page 206
14.3.4 LED Backlighting of Notebook LCDs......Page 207
14.3.5 Case Study: Indirect LED Backlighting for a 15.4 inch Notebook Display......Page 208
14.3.6 Technology for Large screen TV Applications......Page 209
14.3.7 System Setup......Page 210
14.4 Conclusions......Page 212
References......Page 213
15.2 Structure of LED Backlight Units......Page 214
15.3.1 Light guide Type LED Backlight Unit......Page 215
15.3.2 Cavity type LED Backlight Unit......Page 216
15.3.3 Direct light Type LED Backlight Unit......Page 217
15.4.1 Luminance......Page 218
15.4.3 Emission Spectra......Page 219
15.4.7 Lifetime......Page 220
15.5.2 Improvement of Emission Characteristics under Low Ambient Temperature......Page 221
15.6.1 For Moving Images......Page 223
15.7 Conclusions......Page 224
16.1 Introduction......Page 226
16.2 White OLED with a Single layer Emission......Page 227
16.3 White OLED with Multi layer Emission......Page 229
16.5 Stacked WOLED Devices......Page 232
16.6.1 General Lighting......Page 233
16.7 Research and Development Status......Page 234
References......Page 237
17.1 Introduction......Page 238
17.2 Classif cation of Inorganic EL Devices......Page 239
17.3.1 Dispersion type EL s......Page 240
17.4 High luminance Inorganic EL Devices......Page 245
17.5 Practical Examples of Backlight Use......Page 246
References......Page 247
18.2 Field Electron Emitter......Page 248
18.4 Cathodoluminescent Phosphor......Page 250
18.5 Issues Relating to Practical Field Emission Backlights......Page 251
References......Page 252
Part
Three—Optical Components......Page 254
19.1 Introduction......Page 256
19.2.2 Injection Molding Materials......Page 257
19.3.1 Optical Transparency......Page 258
19.3.3 Refractive Index......Page 260
19.5 Applications to LCD Backlight Units......Page 261
19.5.1 Types of Backlight Units......Page 262
19.5.2 Operating Principle and Structure of an Edge light Type of Backlight Unit......Page 263
19.6.1 Requirements for Plate and Pellet Mold Materials......Page 265
19.6.3 Required Characteristics for Pellets......Page 266
19.7.1 Materials for Extrusion Molding......Page 267
19.8 Conclusions......Page 268
References......Page 269
20.1 Introduction......Page 270
20.2 PMMA Light Diffuser Plates......Page 271
20.3 MS and PS Light Diffuser Plates......Page 272
20.4 Trends in Light Diffuser Plates......Page 274
20.5 LED Light Sources and Diffusing Plates......Page 275
21.2 Fundamentals of Ref ection and Refraction......Page 276
21.3.2 Lens Films with Round tipped Lenses ( RBEF )......Page 278
21.3.5 Upward Direction Lens Films......Page 279
21.4 Lens Films (Downward Direction)......Page 280
21.5.1 Functions......Page 281
21.6 Resin type Specular Ref ection Films......Page 282
21.7.3 Monitors and TV s......Page 283
21.7.4 Combination Films......Page 284
21.8.3 Environmental Concerns......Page 285
References......Page 286
Index......Page 288