1. Liquid Crystal DisplaysBy
Farrell Rogers
Materials Research Science and Engineering Center
(MRSEC)
Interdisciplinary Education Group (IEG)
University of Wisconsin
Madison, Wisconsin
RET Program
Summer 2006

2. NanoScience
Nanoscience involves the study and creation of materials, devices, and systems through the manipulation of individual atoms and molecules.
Describes research where the characteristic dimension of 1 or more plane is less than about 100 nanometers(.1 micron).
Manufactured products are made from atoms. The properties of those products depend on how those atoms are arranged.
If we rearrange the atoms in….
coal we get diamonds or graphite.
sand (adding a few other trace elements) we get computer chips.
dirt, water and air we can make potatoes.
Unlike their larger or “macro” counterparts, nanoparticles often display unique properties that may be of use for various applications(Rattner & Rattner, 2003).

3. States of Matter Solid Liquid crystal Liquid Gas
“fourth state of matter”
Liquid
Gas
Images: MacDonald, R. “Liquid Crystals - Fascinating State of Matter or "Soft is beautiful". Accessed

4. What is a Liquid Crystal?
Liquid Crystal – a stable phase of matter characterized by anisotropic properties without the existence of a 3-dimensional crystal lattice – generally lying between the solid and isotropic (“liquid”) phase.
Discuss

5. Isotropic vs. Anisotropic Liquids and gases
(uniform properties in all directions).
vs. Anisotropic
Do not follow patterns, Some phases are combined and orientation is NOT the only way to characterize
Liquid Crystals
have orientational order

6. Liquid Crystal Phases There are 2 basic phases Nematic & Smectic
Anisotrpic substances
may go through one or several
Liquid Crystal Phases
Do not follow patterns, Some phases are combined and orientation is NOT the only way to characterize
Images from Sheffield Hallum University, United Kingdom, 2006

7. Liquid Crystal Model

8. Phase Transitions Discuss
Molecular Expressions, NHMFL-FSU( accessed, 2006.)

9. Project Goals
My Curriculum Research Project focused on Liquid Crystal
Explaining Liquid Crystals
Explaining Polarization
Adapting the LCD Watch Dissection for my students
Designing a middle grade activity to create a simple LCD Panel

10. Activity #1 Introducing Liquid Crystals
After reading a brief history and description of Liquid Crystals, students will answer some questions and use drawings to compare the 4 states of matter.
I designed a questionaire for this activity.

11. Activity #1 Comparing Liquid Crystals
Part II: Visualizing Liquid Crystals
1-In the box below draw how the molecules of each of the following phases might be arranged if you could see them.
Solid Phase LC Phase Liquid Gas

12. Activity #2 Part 1: Polarized Light
This activity involved having kids explore the properties of light using 2 polarized lenses. They will compare light from an CRT TV, LCD Screen and from an incandescent bulb.

13. Activity #1 Pics

14. Activity #2 Part 2: “To Twist or Not to Twist, a Play of Polarization”
This is a student run Demo where different kids play different roles to demonstrate the parts of a Liquid Crystal Display.
Image: How Stuff Works, 2006

15. Activity #3 Adapting the LCD Watch Dissection
MRSEC/IEG already has an excellent lab for this at
The only thing I would add would be testing to see if Dry Ice was cold enough to solidify the LC and prevent the LCD Panel from Functioning.
(Maybe Next Year? Please :o)

16. Activity #4 Making a Liquid Crystal Display
Everything seems easier once you figure it out.
I had a few obstacles such as…
Which LC, How much LC, How thick the spacers should be, How much voltage, Do I need an orientational polymer, How do I apply the chemicals, etc.

17. Materials 5CB Liquid Crystal ITO Conducting Glass slides
Polyvinyl Alcohol
Polarized Lenses
Capillary tube Pipettes
Binder Clamps
9V Battery
Glass Petri dishes
Hot Plate
Alligator clamps
Copper wire
Saran Wrap
Cotton Cloth
Tweezers
Q-tips
eyedropper

18. LCD Alignment
Natural state
Sharp Technologies, Inc
When coming into contact with a finely grooved surface (alignment layer), LC molecules line up parallel along groove due to their rod-like shape. Coating ITO glass with a layer of PVA and rubbing repeatedly creates these grooves.

19. LCD Orientation
Sharp Technologies, Inc
The molecules along the upper plate point in direction 'a' and those along the lower plate in direction 'b,' thus forcing the liquid crystals into a twisted structural arrangement./ (figure shows a 90-degree twist) (TN type liquid crystal)

20. Unique Properties of Liquid Crystals
The orientation of Liquid Crystals can be affected by…
Pressure
Temperature
Electrical Field
S. Palmer, LCTec Displays, Inc. 2005

21. LCD Preparation Removing the PVA at one edge Checking the ITO Glass
Rubbing the PVA to create an alignment layer
Placing the Saran Wrap Spacers
Applying the Liquid Crystal
Placing the Polarizers at 90°

22. The LCD Sandwich
Modified from S. Palmer, LCTec Displays, Inc. 2005

23. LCD Technology Electrical-field NOT Applied Light IS transmitted
IS Applied
Light NOT transmitted

24. LCD Results Electrical-field NOT Applied Light IS transmitted
Electrical-field IS Applied
Light NOT transmitted

25. LCD In Action
pics\LCD13.mov

26. LCD Applications
The Nematic phase is most commonly used in Liquid Crystal Displays (LCD)

27. Prior Knowledge and Timing
LC’s can be discussed during any of the
following units:
States of Matter/Phase Changes
Properties of Light
Electricity
Possibly make it a long term activity discussing what an LC is during Matter, then doing the Watch Dissection & LCD Fabrication during the other Units?

28. Standards Addressed Science Language Arts
Nature of Science
History of Science
Variables and Experimentation
Chemistry
Matter
Physical Science
Waves
Energy
Electricity
Technology & Society
Language Arts
Main Idea
Using Context Clues
These activities would be appropriate for Science students in grades 8-12.

29. References References:
1-Rudy, Lisa Jo. “Between the Boundaries of the Known The Molecular World between Solid and Liquid”. Copyright ©2004 University of Pennsylvania. School of Arts and Sciences Updated September 1, 2004.
Accesses
2-How Stuff Works. Building Your Own LCD. July 2006.
3- The University of Wisconsin. Materials Research Science and Engineering Center (MRSEC)-
Interdisciplinary Education Group (IEG)
Engineering Centers Building
4-Ratner, M. & Ratner, D. Nanotechnology, A Gentle Introduction to the Next Big Idea, Pearson Education, Inc.
5- Kent State University. Liquid Crystal Institute,
Accessed
6- Macdonald, R., “Liquid Crystals - Fascinating State of Matter or "Soft is beautiful". Optical Institute of the Technical University of Berlin   Straße des 17. Juni 135, Berlin, Germany
7-Touch Screen info
Accesses
8-Universität Hamburg Liquid Crystal Database
9-Waclawik, Eric R. “Liquid-Crystal Displays: Fabrication and Measurement of a Twisted Nemetic Liquid Crystal Cell”. Journal of Chem. Engineering 81, no. 6, (2004)
10-Ondris-Crawford, R., Crawford, G.P., and Doane, J.W. “Liquid-Crystals, Phases of the Future”. The Physics Teacher 30, Sept. (2004)
11-Sadlej-Sosnowska, Nina. “Imposed Orientation of Dye Molecules by Liquid Crystals and an Electric Field”. Journal of Chem. Ed. 57, no. 3 (1980)
12-Daigle, Stephen M.. “Investigating the Bistibility of 4’-octyl-4-Biphenylcarbonitrile”. Liquid Crystal Institute, Kent State University (July 2004).
Accesses
13- Sharp Technologies, Inc
1. The Principles of LCD Technology

30. Thank you
Wendy Crone, Ph.D.: MRSEC Director of Education, University of Wisconsin
Greta Zenner, Ph.D.: MRSEC Assistant Director of Education, University of Wisconsin
MRSEC-RET program
Dana Horoszewski , Ph.D.: IEG Mentor
Ken Gentry, Ph.D.: IEG Mentor
Dr. George Lisensky, Ph.D.: IEG Mentor, Professor of Chemistry, Beloit College
University of Wisconsin
NSF, Research Experiences for Teachers(RET Programs)
"We are grateful to the National Science Foundation through the Materials Research Science and Engineering Center (MRSEC) on Nanostructured Interfaces (DMR and DMR ) at the University of Wisconsin-Madison”