A novel fabrication method for the mold insert of microlens arrays by hot embossing molding

2006 ◽  
Vol 46 (12) ◽  
pp. 1797-1803 ◽  
Author(s):  
Y. K. Shen
Keyword(s):  
Mold Insert ◽  
Hot Embossing ◽  
Fabrication Method ◽  
Microlens Arrays

Microlens Fabrication by the Modified LIGA Process and Hot Embossing Process

2002 ◽  
Author(s):  
Sung-Keun Lee ◽  
Hyun Sup Lee ◽  
Seung S. Lee ◽  
Tai Hun Kwon
Keyword(s):  
Molecular Weight ◽  
Surface Tension ◽  
Thermal Treatment ◽  
Mold Insert ◽  
Hot Embossing ◽  
X Rays ◽  
Fabrication Technology ◽  
Microlens Arrays ◽  
Good Surface ◽  
Good Surface Roughness

Microlens and microlens arrays is realized using a novel fabrication technology based on the exposure of a resist, usually PMMA, to deep X-rays and subsequent thermal treatment. The fabrication technology is very simple and produces microlenses and microlens arrays with good surface roughness (less than 1 nm). The molecular weight and glass transition temperature of PMMA is reduced when it is irradiated with deep X-rays. The microlenses were produced through the effects of volume change, surface tension, and reflow during thermal treatment of irradiated PMMA. Microlenses were produced with diameters ranging from 30 to 1500 μm. Moreover, fabrication of the microlens through the hot embossing process is studied based upon a microlens mold insert fabricated by the modified LIGA process. A hot embossing machine is designed and manufactured. The hot embossing process follows steps of heating a mold to desired temperature, embossing a mold insert on substrate, cooling the mold to deembossing temperature, and deembossing.

Novel fabrication method of microlens arrays with High OLED outcoupling efficiency

2016 ◽  
Vol 77 ◽  
pp. 104-110 ◽  
Author(s):  
Hyun Soo Kim ◽  
Seong Il Moon ◽  
Dong Eui Hwang ◽  
Ki Won Jeong ◽  
Chang Kyo Kim ◽  
...  
Keyword(s):  
Fabrication Method ◽  
Microlens Arrays

Design of Precision Hot Embossing Machine for Micro-Patterning on PMMA

2021 ◽  
Author(s):  
Sridhar P ◽  
Supreet Singh Bahga ◽  
Jitendra P. Khatait
Keyword(s):  
Substrate Surface ◽  
Mold Insert ◽  
Cost Effective ◽  
Hot Embossing ◽  
Pmma Substrate ◽  
Kinematic Coupling ◽  
Heating And Cooling ◽  
Micro Patterning ◽  
Micro Channels ◽  
Set Up

Abstract A microfluidic chip requires micro-channels to be created on a substrate. This paper focuses on the design and development of a precision hot embossing machine for replication of microstructures on a PMMA substrate. Kinematic coupling using three spherical balls in radial v-grooves is used to achieve precise positioning of the mold insert with the base. Flexure based parallel guidance mechanism is used for one DOF motion required for the embossing process. The mechanism allows the motion of the mold normal to the substrate surface. Flexure based kinematic coupling with the thermal center is designed to mitigate thermal stress build-up during heating and cooling of the mold insert. An Arduino-based micro-controller is developed to control the temperature profile during the process. A prototype is fabricated and experiments are performed with an aluminium mold insert on a PMMA substrate. The result shows the feasibility of the concept and the set-up can be used to develop a cost-effective precision hot embossing machine for creating micro-patterns for microfluidic applications.

Study on Micro Fabrication of Mold Insert for Microlens Arrays by Micro Dispensing

2007 ◽  
Vol 364-366 ◽  
pp. 48-52
Author(s):  
Yung Kang Shen ◽  
Yi Lin ◽  
Dong Yea Sheu ◽  
Ming Der Ger ◽  
Yi Han Hu ◽  
...  
Keyword(s):  
Focal Length ◽  
Surface Profile ◽  
Mold Insert ◽  
Microlens Array ◽  
Hot Embossing ◽  
Silver Layer ◽  
Processing Temperature ◽  
Master Mold ◽  
Processing Parameter ◽  
Halogen Light

This work used micro dispensing technology to fabricate the master of microlens array, then uses electroforming technology to replication the Ni mold insert of microlens array and finally used micro hot embossing to replicate the plastic microlens array. This work used the Si10 resin by AutoStrade Company for dispensing material. The resin material was exposed to 80W halogen light. The resin will be hardened and become convex by surface tension effect on exposition. It can be used as the master of microlens array. This work sputtered a silver layer of 150 nm thick on the master for conducting electricity layer. The electroforming technology replicateed on the Ni mold insert from the master of microlens array. Finally, the micro hot embossing technology was used to replicate the molded microlens array. The molding experiment used PMMA and PC optical film. The experiment studied the influence of processing parameters of hot embossing by processing temperature, embossing pressure, embossing time and de-molding temperature. This work used the Taguchi’s Method to search the best processing parameter for molded microlens array. This work used the microscope, surface profiler and SEM to measure the surface profile of master, mold insert and molded microlens array. This work also used AFM to measure the surface roughness of master, mold insert and molded microlens array. In addition, this work measured the optical strength and the focal length to discuss optical characteristics of molded microlens array.

Cavity Filling Analysis for the Fabrication of an Alignment Structure in Micro Hot Embossing

2012 ◽  
Author(s):  
J. A. Gomez ◽  
T. G. Conner ◽  
I.-H. Song ◽  
D.-H. Chun ◽  
Y.-J. Kim ◽  
...  
Keyword(s):  
Flow Behavior ◽  
Mold Insert ◽  
Hot Embossing ◽  
Polymer Flow ◽  
Finite Element Software ◽  
Complete Filling ◽  
Alignment Structure ◽  
Filling Analysis ◽  
Cavity Filling ◽  
Deform 2D

The flow behavior of polymers was analyzed using a commercial finite element software, DEFORM-2D, for the replication of microstructures. An alignment structure for microassembly, a hemisphere-tipped post, was modeled to demonstrate the polymer flow in hot embossing. The mold filling with polymer was evaluated by the heights of molded posts. The results of simulation showed better replication fidelity of the post with the increase of the molding temperature and displacement of the mold insert. The complete filling of a mold cavity was achieved at the molding temperatures of 112.5, 125, 137.5, and 150°C when the displacements were 1.5, 2.0 and 2.5 mm. The model can be used to design the process parameters for the reliable replication of microstructures.

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