Projection Displays Second Edition

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

3 Projection Displays

4 Wiley-SID Series in Display Technology Series Editor: Anthony C. Lowe Consultant Editor: Michael A. Kriss Display Systems: Design and Applications Lindsay W. MacDonald and Anthony C. Lowe (Eds) Electronic Display Measurement: Concepts, Techniques, and Instrumentation Peter A. Keller Projection Displays Edward H. Stupp and Matthew S. Brennesholtz Liquid Crystal Displays: Addressing Schemes and Electro-Optical Effects Ernst Lueder Reflective Liquid Crystal Displays Shin-Tson Wu and Deng-Ke Yang Colour Engineering: Achieving Device Independent Colour Phil Green and Lindsay MacDonald (Eds) Display Interfaces: Fundamentals and Standards Robert L. Myers Digital Image Display: Algorithms and Implementation Gheorghe Berbecel Flexible Flat Panel Displays Gregory Crawford (Ed.) Polarization Engineering for LCD Projection Michael G. Robinson, Jianmin Chen, and Gary D. Sharp Fundamentals of Liquid Crystal Devices Deng-Ke Yang and Shin-Tson Wu Introduction to Microdisplays David Armitage, Ian Underwood, and Shin-Tson Wu Mobile Displays: Technology and Applications Achintya K. Bhowmik, Zili Li, and Philip Bos (Eds) Photoalignment of Liquid Crystalline Materials: Physics and Applications Vladimir G. Chigrinov, Vladimir M. Kozenkov and Hoi-Sing Kwok Projection Displays, Second Edition Matthew S. Brennesholtz and Edward H. Stupp Published in Association with the Society for Information Display SOCIETY FOR INFORMATION DISPLAY

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

6 This edition first published John Wiley & Sons Ltd Registered office John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at The right of the author to be identified as the author of this work has been asserted in accordance with the Copyright, Designs and Patents Act All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought. Library of Congress Cataloging-in-Publication Data Brennesholtz, Matthew S. Projection displays / by Matthew S. Brennesholtz, Edward H. Stupp. 2nd ed. p. cm. (Wiley series in display technology) Includes bibliographical references and index. ISBN (cloth) 1. Information display systems. 2. Liquid crystal displays. 3. Projectors. I. Stupp, Edward H. II. Title. III. Title: Projection displays. TK7882.I6P dc A catalogue record for this book is available from the British Library. ISBN Set in 9/11pt Times by Integra Software Services Pvt. Ltd, Pondicherry, India Printed and bound in Great Britain by Antony Rowe Ltd, Chippenham, Wiltshire, UK

7 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 Projection 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

8 vi CONTENTS Effects of leakage Charging currents Technologies α-si TFTs Poly-Si TFTs Crystalline silicon active matrices Active matrices based on two terminal devices 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 53 5 Micro-electromechanical Devices DMD Device Operation Gray Scale Contrast and DLP Pixel Design Linear MEMS Arrays Grating Light Valve GEMS System MEMS Scanning Mirrors 66 6 Filters, Integrators and Polarization Components Factors affecting Projector Optical Performance Component Efficiency 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 Integrators Lenslet Integrators Rod Integrators Integrators for Projectors with Laser or LED Illumination Other Integrator Types Light Guides 104

9 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 RPTV systems 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 Choice of Laser Wavelengths Laser Designs Suitable for Projection Applications 183

10 viii CONTENTS Laser architectures Laser wavelength generation Laser Safety Light Emitting Diodes as Projection Light Sources Performance Improvements in LEDs for Projection Color with LEDs Thermal Issues with LEDs LED Drive Issues Efficacy and Lumen Output Spectral Characteristics of Lamps Lamp Spectral Emission Lines Light Distribution from a HID Lamp Lamp Life Lamp Servicing Failure Mechanisms Measurement of lamp life Reflectors and Other Collection Systems Reflectors with Conic Sections Compound Reflectors Constant Magnification Reflectors Refractive Collection Systems Collection Systems for LEDs Lamp Ballasts and Ignitors Scanned Projection Systems CRT Projectors Three-lens CRT Projectors One-lens CRT Projectors Convergence of CRT Projection Systems Lumen Output of CRT Projectors Scanned Laser Projectors Raster Scan Patterns Laser Projectors with Two-axis Scanning Laser Projectors with a Single Scanning Axis Microdisplay System Architectures Microdisplay Systems Three-panel Systems with Transmissive Microdisplays Three-panel Equal Path Unequal Path Systems 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 Single-panel Projectors Sub-pixelated Projectors Microfilter projector Angular color separation projectors Resolution of sub-pixelated projectors 246

11 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 Étendue Definition of Étendue Étendue at a flat surface Étendue Limited Systems Lumen vs Étendue Function Étendue conserving transformations Shape conversion Usable étendue Limitations of lumen vs étendue model Integrators and Lumen Throughput Overfill Losses Integrator Étendue 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

12 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 vs film Image Quality Metrics 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 Image Content-dependent Adaptive Processes Image Artifacts Spatial Artifacts Moiré: Alias and Beat Frequencies Origins of Moiré Screen Door Effect or Pixelation Depixelation 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 361 Appendix 1 Radiometry and Photometry 365 Appendix 2 Colorimetry 371 A2.1 Introduction 371 A2.2 CIE Color Matching Functions 372 A2.3 Calculation of Color 373 A2.4 Color Temperature 375 A2.5 The Chromaticity Diagram 375 A2.6 Color-luminance Difference Formulas 375 A2.7 Measurement of Color 377 A2.8 Tabulated CIE Photopic Color Matching Functions 380

13 CONTENTS xi Appendix 3 Lumen vs Etendue Parametric Model 383 A3.1 Introduction 383 A3.2 Definition of Étendue 384 A3.3 Étendue at a Flat Surface 385 A3.4 Étendue 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

15 Foreword When the first edition of this book was published, it was the third volume in this series. Now, nine years later, it is the first to appear as a second edition in a series which its publication will increase to fifteen works. Much has changed in the intervening years. In my foreword to the first edition, I wrote Projection displays have existed since before the invention of the cinema, but it is comparatively recently that there has been rapid development of electronically addressed projection display technologies and literally an explosion in their successful commercialisation. Well, that last statement was true at the time, but what no-one foresaw was that one of those explosive successes, rear projection TV, would implode as rapidly as it had exploded. Other changes over almost a decade are that new UHP, LED, laser and other light sources have become or are becoming available some of them at commercial prices. The spectral properties of new light sources have enabled colour gamuts to be increased to much wider values than ever before possible. Liquid crystal on silicon displays and projection screen designs have been developed extensively. Following a successful resolution of the content security issue, electronic cinema technology is finally being rolled out at a significant and increasing rate. This edition contains substantial revisions and additions to reflect technological progress made and the increased maturity of the topic. Those sections covering light sources for projection displays, liquid crystal on silicon, display colour gamuts, electronic cinema and projection screen design having received the greatest amount of revision. It retains the format of the first edition, apart from the fact that it is not now divided into sections. The book is structured in a way which makes it easy to read straight through or as a source of information into which the reader may selectively dip. Chapter 1 describes the structure. Chapter 2 is an overview of markets and applications which will help those not familiar with the subject to place it in context and perspective. Chapters 3 to 9 cover technical aspects of all the components of projection displays. Chapters 10 to 14 deal with the systems aspects of architecture and performance, display characterisation and artefacts. Four appendices cover the basics of radiometry and photometry, colorimetry, étendue and a glossary. In its first edition, this book proved to be an invaluable source of information for scientists, engineers and technicians working in the field of projection display technology and projection display product

Projection Displays Second Edition

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 Contents Foreword Preface to the Second