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Liquid Crystals. A Unique State of Matter. Prepared By: Joseph A. Castellano, Ph.D., RESEED Silicon Valley, 2008. Solid or Crystal State. Liquid Crystal State. Liquid Crystal Ordering. Attractive Forces Hold Molecules in Line. Single Molecules. - PowerPoint PPT Presentation
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Liquid CrystalsLiquid CrystalsA Unique State of MatterA Unique State of Matter
Prepared By: Joseph A. Castellano, Ph.D., RESEED Silicon Valley, 2008Prepared By: Joseph A. Castellano, Ph.D., RESEED Silicon Valley, 2008
Solid or Crystal StateSolid or Crystal State
Liquid Crystal StateLiquid Crystal State
Liquid Crystal OrderingLiquid Crystal Ordering
SingleMolecules
Attractive Forces Hold Molecules in Line
Each line of molecules can slide past each other
Normal Liquid StateNormal Liquid State
Solid Liquid Crystal Liquid
Heat Heat
Cool Cool
Changes from One State to AnotherChanges from One State to Another
A Completely Reversible Physical ChangeA Completely Reversible Physical Change
Liquid Crystal MoleculeLiquid Crystal Molecule
Licristal K-18 made by E. Merck, Darmstadt, Germany
Liquid Crystals under a MicroscopeLiquid Crystals under a Microscope
Scanning Tunneling MicroscopeScanning Tunneling Microscopephoto of a liquid crystal mixturephoto of a liquid crystal mixture
100 x 100 Angstrom Units100 x 100 Angstrom Units
Molecular model of the mixtureMolecular model of the mixture
Source: Frommer, J., Liquid Crystals Today, 3 (2) 1993;Photos taken at IBM Almaden Research Center
Observing the Liquid Crystal StateObserving the Liquid Crystal State
Heat Heat
CoolCool
Solid(Crystals)
LiquidCrystal
(Opaque)
ClearLiquid
A Completely Reversible Physical ChangeA Completely Reversible Physical Change
Phase Change DiagramPhase Change DiagramFor K-18 Liquid CrystalFor K-18 Liquid Crystal
Drop of Liquid Crystal on GlassDrop of Liquid Crystal on Glass
Thin Layer of Liquid Crystal inThin Layer of Liquid Crystal in““Nematic” (Thread-like) PhaseNematic” (Thread-like) Phase
Motion of Liquid Crystals inMotion of Liquid Crystals inElectric FieldsElectric Fields
Liquid Crystals UsesLiquid Crystals Uses
• Displays for Electronic ProductsDisplays for Electronic Products- ComputersComputers- TelevisionTelevision- Cell PhonesCell Phones- iPODsiPODs- Clocks and watchesClocks and watches- Instrument gaugesInstrument gauges- Thermometers Thermometers
• Temperature SensorsTemperature Sensors• Biological ResearchBiological Research• Chemical Structure AnalysisChemical Structure Analysis
Liquid Crystals Displays (LCDs)Liquid Crystals Displays (LCDs)
• Why Liquid Crystals?Why Liquid Crystals?- Very Low Power ConsumptionVery Low Power Consumption- Low Voltage OperationLow Voltage Operation- Very Thin DisplayVery Thin Display- Compatible with Digital ElectronicsCompatible with Digital Electronics- Can be made in many different sizesCan be made in many different sizes
First Liquid Crystal DisplayFirst Liquid Crystal Display
1967 – RCA Laboratories1967 – RCA Laboratories
First Watches to use LCDsFirst Watches to use LCDs
19701970 19721972
First LCD Computer DisplaysFirst LCD Computer Displays
8 x 3-inch8 x 3-inchScreensScreens
19831983
First LCD Color TelevisionFirst LCD Color Television
2-inch diagonal screen -19832-inch diagonal screen -1983
Simple Version of Liquid CrystalSimple Version of Liquid CrystalTV Display AssemblyTV Display Assembly
Cross-section of One Picture ElementCross-section of One Picture ElementIn Color Liquid Crystal TV DisplayIn Color Liquid Crystal TV Display
Increasing Screen Size of LCD TelevisionsIncreasing Screen Size of LCD Televisions
Increasing Screen Size of LCD TelevisionsIncreasing Screen Size of LCD Televisions
45-inch screen45-inch screenSharp - 2000Sharp - 2000
52-inch screen52-inch screenLG.Philips - 2003LG.Philips - 2003
Increasing Screen Size of LCD TelevisionsIncreasing Screen Size of LCD Televisions
82-inch screen82-inch screenSamsung – 2005Samsung – 2005
Increasing Screen Size of LCD TelevisionsIncreasing Screen Size of LCD Televisions
100-inch screen100-inch screenLG.Philips – 2006LG.Philips – 2006