Projection Displays Second Edition

Transcription

1 Projection Displays Second Edition by Matthew S. Brennesholtz Insight Media, USA Edward H. Stupp Stupp Associates, USA WILEY A John Wiley and Sons, Ltd, Publication

2 Contents Foreword Preface to the Second Edition About the Authors xiii xv xix 1 Introduction Overview of Projection Displays Book Organization What is not Covered 4 2 Markets and Applications Overview Microdisplays, Light Valves and Light Amplifiers Emissive Systems Laser-based Projection Technology Applications and Performance Requirements Differentiators among Projectors Requisite Luminance Levels Flux requirement for presentation and auditorium applications Resolution Electronic Cinema 15 3 Emissive Image Sources Projection CRTs Luminous Output of Proj ection CRTs Phosphors Resolution of Projection CRTs Spot Size of Beam Light Collection/Curvature Field-emission Devices 26 4 Liquid Crystal Light Valves and Microdisplays Active Matrices Operation of Active-matrix Circuits 31

3 vi CONTENTS Effects of leakage Charging currents Technologies ce-si TFTs Poly-Si TFTs Crystalline silicon active matrices Active matrices based on two terminal devices 4.2 Liquid Crystal Effects Liquid Crystal Cells Nematic Cells Parallel aligned layer cells Twisted nematic cells Polymer-dispersed Liquid Crystal (PDLC) Other Liquid Crystal Effects Liquid Crystal Effects for Reflective Microdisplays Liquid Crystal Inversion Micro-electromechanical Devices 5.1 DMD Device Operation Grayscale Contrast and DLP Pixel Design 5.2 Linear MEMS Arrays Grating Light Valve GEMS System 5.3 MEMS Scanning Mirrors Filters, Integrators and Polarization Components 6.1 Factors affecting Projector Optical Performance 6.2 Component Efficiency 6.3 Spectral Filters Fresnel Reflection at Optical Surfaces Dichroic Filters Dichroic filters at non-normal incidence Dichroic filters in polarized light Dichroic filters in the imaging path Anti-reflection coatings Absorptive Filters Electrically Tunable Color Filters Mirrors Total Internal Reflection TIR prisms for angular separation Filters for UV Control Filters for IR Control Indium-Tin Oxide and Other Transparent Electrodes 6.4 Integrators Lenslet Integrators Rod Integrators Integrators for Projectors with Laser or LED Illumination Other Integrator Types Light Guides

4 CONTENTS vii 6.5 Polarization Components Absorptive Polarizers Reflective Polarizer Technology Brewster angle reflection 109 (a) Brewster plate 109 (b) MacNeille polarizing prisms Birefringent multilayer reflective polarizer Bertrand-Feussner prism Wire grid polarizers Other reflective polarizers Polarization Conversion Systems Polarization recycling Polarizing Beam Splitters in the Imaging Path Compensation Films Projection Lenses and Screens Projection Lenses Three-lens Projectors Single-lens Projectors Zoom Lenses, Focal Length and Throw Ratio Projection Lens Offset Matching the Projection Lens to the Illumination Optical Path Projection Screens Projection Screen Gain Multiple Projectors and Screen Gain Rear Projection Screens Fresnel lens Fresnel lenses for thin RPTVsystems Rear projection CRT screens 152 (a) Double lenticular screens 152 (b) TIR screens Microdisplay and light-valve rear-projection systems Front Projection Screens Light rejecting front projection screens Speckle in Projected Images Speckle in Rear Projection Systems Speckle with Laser Illumination Light Sources for Light-valve and Microdisplay Projection Systems Lamp Parameters Types of Projection Lamps Xenon Lamps Metal-halide Types The UHP Lamp Temporal properties of UHP lamps Tungsten-halogen Lamps Electrodeless Lamps Lasers as Projection Light Sources Л Choice of Laser Wavelengths Laser Designs Suitable for Projection Applications 183

5 CONTENTS Laser architectures Laser wavelength generation Laser Safety 8.4 Light Emitting Diodes as Projection Light Sources Performance Improvements in LEDs for Projection Color with LEDs Thermal Issues with LEDs LED Drive Issues 8.5 Efficacy and Lumen Output 8.6 Spectral Characteristics of Lamps Lamp Spectral Emission Lines 8.7 Light Distribution from a HID Lamp 8.8 Lamp Life Lamp Servicing Failure Mechanisms Measurement of lamp life 8.9 Reflectors and Other Collection Systems Reflectors with Conic Sections Compound Reflectors Constant Magnification Reflectors Refractive Collection Systems Collection Systems for LEDs 8.10 Lamp В allasts and Ignitors Scanned Projection Systems 9.1 CRT Projectors Three-lens CRT Projectors One-lens CRT Projectors Convergence of CRT Projection Systems Lumen Output of CRT Projectors 9.2 Scanned Laser Projectors Raster Scan Patterns Laser Projectors with Two-axis Scanning Laser Projectors with a Single Scanning Axis Microdisplay System Architectures 10.1 Microdisplay Systems 10.2 Three-panel Systems with Transmissive Microdisplays Three-panel Equal Path Unequal Path Systems 10.3 Three-panel LCoS Projector Architectures Three Polarizing Beamsplitters with a Dichroic Combiner Four-cube LCoS Architectures Four-panel, high contrast LCoS architecture Three-panel, Three-lens Projectors 10.4 Single-panel Projectors Sub-pixelated Projectors Microfilter projector Angular color separation projectors Resolution of sub-pixelated projectors

6 CONTENTS ix Color-field Sequential Systems Addressing color-field sequential systems Color wheel and related systems Three-light-source field sequential systems Address-and-flash systems Rotating drum systems Scrolling color systems Two-panel Systems Schlieren Optics-based Projectors Dark Field and Bright Field Systems Schlieren Light-valve Systems Stereoscopic 3D Projectors Separation by Polarization Stereoscopic 3D with Color Separation Eye-sequential 3D Systems with Active Glasses Modeling Lumen Output Simplified Model Light Collection and Etendue Definition of Etendue Etendue at aflat surface Etendue Limited Systems Lumen vs Etendue Function Etendue conserving transformations Shape conversion Usable etendue Limitations of lumen vs etendue model Integrators and Lumen Throughput Overfill Losses Integrator Etendue and Collection Efficiency Microdisplay and Light-valve Properties Panel Transmission Modulation Efficiency Duty Cycle Full Colorimetric Model of the Projector White Light Throughput prior to Color Correction Color Correction to the desired White Point Single-panel Color Sequential Projectors Colorimetric and Throughput Issues with Projectors with more than Three Primary Colors Color Separation Efficiency Problems with Lumen Throughput Calculations Lumen Output Variation in Production Projector Lumen Throughput Throughput of a Simple Transmissive Projector Throughput in a Three-panel Projector Throughput Estimate using the Full Colorimetric Model Characteristics and Characterization Characteristics of the Human Visual System Spatial Characteristics of the Image 313

7 x CONTENTS Pixel Count Modulation Transfer Function MTF of raster-scanned displays MTF of sampled systems MTFs of other elements Convergence MTF of projection screens MTF of electronic images vsfilm Image Quality Metrics 13.3 Luminance, Contrast and Color Luminance and Brightness Measurement of luminance ANSI lumens Center weighted lumens Luminance patch tests Contrast Colorimetry The specification of color The gamut of real colors White point of displays Color gamuts of displays Expanded color gamuts and displays with more than three primary colors Measurement of the Luminance and Color of Projection Systems Display Gamma and Gray Scale 13.4 Image Content-dependent Adaptive Processes 14 Image Artifacts 14.1 Spatial Artifacts Moire: Alias and Beat Frequencies Origins of Moire Screen Door Effect or Pixelation Depixelation 14.2 Temporal Artifacts Flicker Image Smear, Judder and Motion Blur Artifacts in Color-field Sequential Systems Color breakup due to motion in the image Color breakup due to saccadic motion of the eye Appendix 1 Radiometry and Photometry Appendix 2 Colorimetry A2.1 Introduction A2.2 CIE Color Matching Functions A2.3 Calculation of Color A2.4 Color Temperature A2.5 The Chromaticity Diagram A2.6 Color-luminance Difference Formulas A2.7 Measurement of Color A2.8 Tabulated CIE Photopic Color Matching Functions

8 CONTENTS xi Appendix 3 Lumen vs Etendue Parametric Model 383 A3.1 Introduction 383 A3.2 Definition of Etendue 384 A3.3 Etendue at a Flat Surface 385 A3.4 Etendue of a Cylindrical Surface 385 A3.5 Lamp/Reflector Model 386 A3.6 Comparison of Measured Data to the Model 389 Appendix 4 Glossary 393 Index 425