58
Intended Learning Outcomes for This Topic
2
➌ Enumerate properties of human color vision relevant to embedded systems
By the end of this topic, you should be able to:
➋ Propose design changes to OLED displays to improve their energy efficiency
➍ Explain the difference between spectral colors and perceived colors
➊ Enumerate the properties of traditional LCDs and OLED displays
➎ Recall existing theories of how wavelengths lead to perceived colors in humans
Properties of Displays
Human Vision and
Color Perception
58
Displays: 25%–50% of Power Dissipation in Mobile Devices
4
/
(%)
Data in chart taken from Android power profiles
[SMR2016a] P. Stanley-Marbell, V. Estellers, and M. Rinard "Crayon: Saving Power through Shape and Color Approximation on Next-Generation Displays", ACM EuroSys 2016.
58
Display Structure Variants
5
Illustration source: Qualcomm, Inc.
Competitive Display Technology.
58
OLED Displays are Structurally Simpler than LCD Displays
6
[TDK’08] “High-Luminance/Long Lifetime Organic EL Display”, TDK Corporation, 2008
[Qualcomm’12] Qualcomm, Inc. “Competitive Display Technology”, 2012
Cathode
Typically metal (e.g., Al)
Light-emitting polymer
Anode
Typically Indium Tin Oxide (ITO)
Glass→
LCD Panel Structure
OLED Panel Structure
Organic Light Emitting Diode (OLED) Panels:
Power dissipation differs in R/G/B sub-pixels
Liquid Crystal Display (LCD) Panels:
Power dissipation dominated by backlight
58
OLED Pixel Chemistry: Light-Emitting Polymers
7
[OSRAM’07] H. Antoniadis, OSRAM Opto Semiconductors, “Overview of OLED Display Technology”, 2007
Poly(p-phenylene vinylene)
Poly(p-phenylene)
Polythiophene
or Cyano-Polyphenylene vinylene
[OSRAM’07]