1. Chap.8 Plastic Optical Devices Manufacturing
Precision Manufacturing and Inspection of Optical Components
Chap.8 Plastic Optical Devices Manufacturing
Speaker: Ching-Yao Huang(黃靖堯)
Advisor: Prof. Yi-Pai Huang(黃乙白教授)
Prof. Chung-Hao Tien(田仲豪教授)
Institute of Electro-Optical Engineering,
National Chiao Tung University, Hsinchu, Taiwan
Jan

2. Outline Injection Molding - Micro Injection Molding
- Introduction
- Micro Injection Molding
- Micro Injection-compression Molding
- Optical Plastic Material
Hot Embossing Molding
- Manufacturing Parameter
- Different ways to Micro Hot embossing Molding
Conclusions

3. Injection Molding Disadvantages: Because of pressure, T, density
Sink mark
Shrinkage
Residual stress
Warpage
filling stage
packing stage
cooling stage

4. Micro Injection Molding
Definition:
The products weight unit uses mg.
Size unit uses μm.
4 types:
Weight
Size 1 mg x 2 μm 3 4
microstructure μm

5. Micro Injection-compression Molding
Add compression mold process base on normal micro injection molding.
Advantages:
Reduce ejection pressure
Reduce residual stress
Reduce molecular orientation
Overcome sink mark and warpage
Increase size precision

6. Micro injection molding Micro injection-compression molding
Comparison
Micro injection molding
Micro injection-compression molding
Molding focus
Filling stage
Post-filling stage
Open mold temperature
Lower than Tg
Lower than Tg and heat balance
Thick product injection
Easy
Hard
Thin product injection
MICM solves the problem of molecular orientation
and residual stress, but also creates the difficulty
in controlling manufacturing.

7. Optical Plastic Material
Material in common use:
Polymethyl methacrylate(PMMA), Polycarbonate(PC), Polystyrene(PS)

8. Optical Plastic Material
PMMA
Good
Bad
Penetrability
Water absorption higher
Weathering quality
UV resistibility
Molding Temperature lower PC
Heat-resistant
Molding temperature higher
Chemical resistant
Molding stress relief
Impact resistant PS
Penetrability
Brittleness
Chip
Electric insulation

9. Outline Injection Molding - Micro Injection Molding
- Introduction
- Micro Injection Molding
- Micro Injection-compression Molding
- Optical Plastic Material
Hot Embossing Molding
- Manufacturing Parameter
- Different ways from Micro Hot embossing Molding
Conclusions

10. Micro Hot Embossing Molding
If pattern’s drawing temperature is high, the product ’s
surface will be coarseness.

11. Manufacturing Parameter
To emboss high-aspect-ratio structures, in addition the following process and material properties have to be taken into account:
Sidewall roughness of the embossing master:<10nm
Sidewall angle : about 90degree.
The chemical interface between master and substrate:
add release agents.
Temperature coefficients : To avoid the creation of additional forces due to the larger shrinkage.
Hot embossing as a method for the fabrication of polymer high aspect ratio structures
Sensors and Actuators A: Physical Volume 83, Issues 1-3, 22 May 2000, Pages , Holger Becker1, , and Ulf Heim

12. Nanoimprint lithography
Electron beam, RIE
mold
RIE
Evaporation metal, acetone
Si substrate
<100nm

13. Soft lithography
Soft lithography uses elastomeric imprint mode to transfer patterns to substrate.
Electron beam
, metal, glass
mold
elastomeric liquid polymer
elastomeric mold

14. Soft lithography 1. micro-contact printing, μCP
Self-assembled monolayer, SAM

15. Soft lithography
2. Replica molding, REM
(PU)

16. Soft lithography
3.Microtransfer molding, μTM

17. Soft lithography
4.Micromolding in capillaries, MIMIC

18. 5. solvent-assisted micromolding, SAMIM
SOFT LITHOGRAPHY
Younan Xia and George M. Whitesides
Department of Chemistry and Chemical Biology, Harvard University, Cambridge,
Annu. Rev. Mater. Sci :153–84
5. solvent-assisted micromolding, SAMIM

19. Step and Flash Imprint lithography
The process doesn’t need large pressure in RT, and
is adoptable for flipping focus disposition because
mold is transparent.

20. Outline Injection Molding - Micro Injection Molding
- Introduction
- Micro Injection Molding
- Micro Injection-compression Molding
- Optical Plastic Material
Hot Embossing Molding
- Manufacturing Parameter
- Different ways to Micro Hot embossing Molding
Conclusions

21. Conclusions The methods of optical plastic devices manufacturing
- micro injection molding
- micro hot embossing molding
The material is suitable or not depend on your purpose.
Manufacturing parameter should be carefully considered.

22. Thanks for your kind attention

23. PDMS(聚二甲基矽氧烷)
Polydimethylsiloxane (PDMS) is the most widely used
silicon-based organic polymer, and is particularly
known for its unusual rheological (or flow) properties.
Its applications range from contact lenses and
medical devices to elastomers, caulking, lubricating
oils and heat resistant tiles.
PDMS is optically clear, and is generally considered
to be inert, non-toxic and non-flammable. It has been
assigned CAS number , and is occasionally
called dimethicone. It is one of several types of silicone
oil (polymerized siloxane).
PDMS
Provides a surface that has a low interfacial free energy
and good chemical stability.
It is durable.
The interfacial property can be changed readily either by
modifying polymers or by treating the surface with plasma,
followed by the formation of SAMs.

25. Glass Transition Temperature
In the study of polymers and their applications, it is important to understand the concept of the glass transition temperature, Tg. As the temperature of a polymer drops below Tg, it behaves in an increasingly brittle manner. As the temperature rises above the Tg, the polymer becomes more rubber-like。

27. Abbe number
In physics and optics, the Abbe number, also known as the V-number or constringence of a transparent material, is a measure of the material's dispersion
The Abbe number V of a material is defined as
where nD, nF and nC are the refractive indices of the material at the wavelengths of the Fraunhofer D-, F- and C- spectral lines (589.2 nm, nm and nm respectively). Low dispersion materials have high values of V.

28. RIE
Reactive ion etching (RIE) is an etching technology used in microfabrication. It uses chemically reactive plasma to remove material deposited on wafers. The plasma is generated under low pressure (vacuum) by an electromagnetic field. High-energy ions from the plasma attack the wafer surface and react with it.

30. SAM SAMs exhibit many attractive characteristics:
ease of preparation, good stability
under ambient laboratory conditions, relatively low densities of defects in the final structures.
Amenability to application in controlling interfacial
(physical, chemical, electrochemical, and biochemical) properties.