A brief introduction of Liquid Lenses and their applications

1. Soheila Hesaraki

2. Out Line
Types of liquid lens
 History of liquid lens used Electro
wetting effect
 The basic idea (Electro wetting
mechanism)
 Components
 Advantages and drawbacks
 Application
 References


3. Types Of Liquid Lens

Fluid membrane interaction

Dielectrophoretic effect

Thermal effect

Electro wetting effect

4. History
17th
century
1936
• Stephen Gray, an English scientist made microscopes by creating waterdrop lenses. He kept the drops from moving around by placing them in holes
drilled in a plate
• Froumkine, experimenting with the use of electric fields to change the
shape of a water drop sitting on a metal surface
• Gorman and his colleagues at Harvard University made the first variablefocus lens, by replacing the metal plate with a transparent conducting plate
1995
2000
• Bruno Berge and Jerome Peseux improved on Gorman's design by covering
•
the transparent electrode with an insulating film, and adding the means for
centering the drop

5. Electro Wetting

With the applied potential, the contact
angle of the conductive liquid was
changed, which was referenced as electro
wetting.

6. Electro Wetting

7. Electro Wetting

8. Liquid Lens structure
The lens has a
simple
structure:
two liquids,of
equal density,
sandwiched
between two
windows in a
conical vessel

9. Traditional way to perform
the Auto Focus function
Mechanism : Moving mechanically the
lens
module to adjust the focal length
Drawbacks:
- Necessity of bulky and fragile motors
- Friction of small parts leading to
damage and malfunction after a few
hundreds of thousands of actuations
- Noise and high power consumption
while moving the mass of the lens
module

10. Advantages
1. No moving parts
2. High Speed : 2/100th of a second
3. Low power consumption: <1 mW (~15 mW with
driver)
4. Silence
5. High shock resistance : thanks to the simple
mechanical structure and iso-density
6. A large focal length range

11. Advantages
7. Small size (Up to 85% smaller than standard
camera lenses) Useful in applications which
need size and weight savings like mobile
phones
8. It has got a wide operating temperature
range i.e. -50 c to 180 c
9. The cost of manufacturing is very less.
10. The curvature and the focal length of the
liquid lens can be switched from concave to
convex.

12. Drawbacks
1. it should not be subjected to
temperature beyond the specified range
or else water will freeze inside it and
this may damage our system. It can be
improved by adding antifreeze like
ethylene glycol
2. Size limitation
(gravity effect and aberration problem
caused by a non-uniform lens Shape)

13. Application
-Barcode readers
- Medical imaging
- Endoscopes
- webcams
- Ophthalmology equipment
- hidden security cameras
- DVD recorders
- Zoom Lens
- - Tumor detection

14. Future Applications
-
A key component of a future implantable
artificial eye

15. Thanks for your attention !


16. References
1.
2.
3.
4.
5.
6.
“ Jihwan Park,” A Liquid Lens Based On Electro
Wetting”, Louisiana State University. Masters
Thesis, August 2007
http://www.varioptic.com
“ SCOBIE, FRASER,CHARLES,” Adaptive Optical
Devises in Vision Science”, Department of Physics
University of Durham. PHD Thesis, September 2012
Liquid Optics Product catalog
“B. Berge,” Liquid Lens Technology: Principle Of
Electro Wetting Based Lenses And Applications To
Imaging,” IEEE Transactions, 2005
http://www.nature.com/naturephotonics