Color in Electronic Display Systems: Advantages of Multi-primary Displays

255 Pages·2019·5.56 MB·English

by  Michael E. Miller

Series in Display Science and Technology
Michael E. Miller
Color in Electronic
Display Systems
Advantages of Multi-primary Displays
Series in Display Science and Technology
Series editors
Karlheinz Blankenbach, FH für Gestaltung, Technik, Hochschule Pforzheim,
Pforzheim, Germany
Fang-Chen Luo, Hsinchu Science Park, AU Optronics, Hsinchu, Taiwan
Barry Blundell, Waiheke Island, New Zealand
Robert Earl Patterson, Human Analyst Augmentation Branch, Air Force Research
Laboratory, Wright-Patterson AFB, OH, USA
Jin-Seong Park, Division of Materials Science and Engineering, Hanyang
University, Seoul, Korea (Republic of)
The Series in Display Science and Technology provides a forum for research
monographsandprofessionaltitlesinthedisplaysarea,coveringsubjectsincluding
the following:
(cid:129) optics, vision, color science and human factors relevant to display performance
(cid:129) electronic imaging, image storage and manipulation
(cid:129) display driving and power systems
(cid:129) display materials and processing (substrates, TFTs, transparent conductors)
(cid:129) flexible, bendable, foldable and rollable displays
(cid:129) LCDs (fundamentals, materials, devices, fabrication)
(cid:129) emissive displays including OLEDs
(cid:129) low power and reflective displays (e-paper)
(cid:129) 3D display technologies
(cid:129) mobile displays, projection displays and headworn technologies
(cid:129) display metrology, standards, characterisation
(cid:129) display interaction, touchscreens and haptics
(cid:129) energy usage, recycling and green issues
More information about this series at http://www.springer.com/series/15379
Michael E. Miller
Color in Electronic Display
Systems
Advantages of Multi-primary Displays
123
Michael E. Miller
Systems Engineering andManagement
AirForce Institute of Technology
Dayton,OH, USA
ISSN 2509-5900 ISSN 2509-5919 (electronic)
Series in DisplayScience andTechnology
ISBN978-3-030-02833-6 ISBN978-3-030-02834-3 (eBook)
https://doi.org/10.1007/978-3-030-02834-3
LibraryofCongressControlNumber:2018959273
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I dedicate this book to my advisors, mentors
and family without whose encouragement I
would not have gained the experience and
knowledge to develop this manuscript.
I would especially like to thank Dr. Helmut
Zwahlen who began calling me Dr. Miller
many years before I earned the title. His
encouragement and work ethic changed my
life. I would also like to thank my former
colleagues at Eastman Kodak Company.
Without their openness to new ideas and their
desire to see OLED change the world, I
would not have been able to explore this
technology. I would especially like to thank
my family for their encouragement and
patience. Without the support of my wife
Karen, son Nathan, and loving parents, none
of this work would have been possible.
Finally, I would like to thank the late Dr. Lou
Silverstein whose work motivated my interest
in this field and whose mentorship and
friendship have been missed since his
untimely passing.
Preface
Colorispartofoureverydayexperienceinbothournaturalandourvirtualworlds.
Color affects our mood, alertness level, and our ability to recognize and identify
objects.Wefrequentlydiscusscolorbymakingstatementssuchas“thecarisblue.”
However,colorisaperception,notanactualcharacteristicofanobject;therefore,it
is more accurate to say “I perceive the car to be blue.” This subtle difference is
important as we think about and discuss color. Color in the natural world is
influencedbythecharacteristicsofanobject,thelightintheenvironmentinwhich
the object is viewed and our own perceptual abilities. Due to its complexity and
importance, color has been studied as a science since the nineteenth century and
several texts describing color science and its application have been written since.
Thebodyofcolorscienceinfluencestheproductionofdyesandpigmentswhich
form the paints and colorants in the products we purchase; the design of lights we
use to illuminate our homes and businesses; the cameras we use to capture natural
images; the encoding, transmission, and decoding schemes we use to store and
transmit images; and display devices we use to view images. In our virtual world,
eachoftheseelementsinfluencesthecolorweperceivefromanelectronicdisplay.
However, the influence of each of these elements in the color system has received
limited attention from display designers.
Inthemiddleofthe1980s,asanundergraduatestudent,Iwasfortunateenough
to read a paper by the late Dr. Lou Silverstein. Dr. Silverstein described the
potentialutilityofincludingapixelhavingayellowcolorfiltertoaugmentthered,
green,andbluefilteredpixelsinaliquidcrystaldisplay,commonlyreferredtoasa
LCD. Reading this first paper on multi-primary display technology, I came to the
realizationthatIneededtounderstandcolorscienceinmuchgreaterdetailifIwas
going to contribute significantly to visual display design.
IbeganmycareerworkingforInternationalBusinessMachine’svisualproducts
division in the late 1980s and early 1990s. I then completed my Ph.D. at Virginia
TechintheVisualDisplayslaboratoryundertheguidanceofDr.HarrySnyderand
Dr. Robert Beaton.
vii
viii Preface
At the Society for Information Display meeting in the spring of 1995, a former
Virginia Tech colleague, in a hushed conversation, pulled what appeared to be a
microscope slide from his jacket. He proceeded to attach the slide to a 9V battery.
Instantly, the slide lit up to show the word “Kodak” in great, green, glowing,
organiclight-emittingdiode(OLED)letters.IjoinedKodakthatfallhopingtowork
on this technology, but, fortuitously, spent several years supporting digital camera
development and digital image processing for photofinishing before having the
opportunitytojoin theOLED effort inthespringof2002. Bytheendof2002,we
were constructing OLED prototypes with filtered red, green, and blue pixels
together with unfiltered white pixels, building upon the knowledge amassed since
reading the paper by Dr. Silverstein. This technology was transferred from Kodak
toLG Display in2009 andhassince beencommercializedinLG’sRGBWOLED
televisions.
Duringthisjourney,Icametounderstandthatmanyoftheassumptionswemade
about color in display devices were predicated upon assumptions about the per-
formanceof camerasor other image capture devices, as well as assumptionsabout
human perception. Further, the design of cameras was based upon assumptions
about the objects that were captured and the lighting of the environment in which
these objects lie, as well as assumptions about human perception. This led to the
realization that to understand color and the design of image capture, transmission,
and display devices really requires much more of a systems view of color.
AsIhavecometounderstandtheseassumptionsandsomecommonfallacies,it
has become evident that to significantly improve these systems, we need a deeper
understanding of not only a part of the system, but the entire system. This under-
standing is particularly important at the current time when technologies employed
across many portions of this system are undergoing rapid evolution. For example,
light-emitting diode (LED) technology is replacing traditional lighting systems.
Highdynamicrange,lightfield,andrangecapturesystemsarereplacingtraditional
imagecapturesystems.Finally,theintroductionofbothorganicandinorganicLED
displaytechnologies,ofteninvirtualoraugmentedrealitysystems,isreplacingand
augmenting traditional liquid crystal displays. Additionally, displays are being
manufactured with higher resolution, making multi-primary displays feasible and
desirable. Unfortunately, few texts have attempted to capture the system interac-
tions that allow a practitioner in one field to understand the interdependencies
of their technology with other technologies in the system.
Not only is technology undergoing rapid evolution but our needs for color are
alsochanging.Asithasnotbeenpossibletorepresentcolorreliablyinmostofour
day-to-day systems, we have settled with the ability to render color to form
“natural-looking” or “preferred” images. However, as we move toward virtual
commerce, telemedicine, and other applications where the quality of color ren-
dering might influence the success or failure of a virtual retailer or a life-altering
medical diagnosis, the need to improve the exactness of color rendering becomes
critical to product success.
Preface ix
Thegoalofthisbookisnottomakeyouacolorscientist.Instead,mygoalisto
introduce you to the intricacies of typical imaging pathways which influence dis-
play design and the perception of the users of a display. This understanding is
particularly important to develop an appreciation for and an understanding of
displayshavingmorethanthreecolorsoflight-emittingelements,displayswerefer
to as multi-primary displays. We will, therefore, look at some of the attributes of
each element in the system before discussing displays. We will then review the
technology to enable color in traditional three-primary (RGB) liquid crystal and
OLEDdisplays.Thisdiscussionwillleadustoexploreadvantagesofmulti-primary
systems. Finally, we will summarize by revisiting the effects of this system on the
future of virtual and augmented reality displays. I hope you enjoy this foray into
color within the digital imaging system as much as I have enjoyed gathering the
knowledge necessary to develop this text.
Dayton, USA Michael E. Miller
Contents
1 Color from a Systems Point of View . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Natural Color Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Digital Color Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Three Dimensions of Color . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4 Color in Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.5 Perceiving the Importance of Color . . . . . . . . . . . . . . . . . . . . 9
1.6 Summary and Questions for Reflection . . . . . . . . . . . . . . . . . . 10
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2 Human Perception of Color . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.1 Structure of the Eye . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2 Sensors of the Eye . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.3 Processing in the Eye . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.4 Processing Beyond the Eye . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.5 Defining Luminance and Contrast . . . . . . . . . . . . . . . . . . . . . . 21
2.6 Defining Chromaticity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2.6.1 Tri-stimulus Values . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2.6.2 Chromaticity Coordinates and Diagram . . . . . . . . . . . 27
2.7 Uniform Color Spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.7.1 CIE 1976 Uniform Chromaticity Diagrams . . . . . . . . . 29
2.7.2 1976 CIE L*u*v* Uniform Color Space . . . . . . . . . . . 31
2.7.3 1976 L*a*b* Uniform Color Space . . . . . . . . . . . . . . 32
2.8 General Color Rendering Index . . . . . . . . . . . . . . . . . . . . . . . 32
2.9 Defining Human Needs for Color . . . . . . . . . . . . . . . . . . . . . . 33
2.10 Summary and Questions to Consider . . . . . . . . . . . . . . . . . . . 35
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
3 Scenes and Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.1 Measurement of Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.1.1 Luminance Measurement . . . . . . . . . . . . . . . . . . . . . . 39
xi