Cost-effective optical manipulation platform suitable for mass production of electronic and light-based devices
An international team of researchers has developed a new light-based manipulation method that could one day be used to mass produce electronic components for smartphones, computers and other devices. A cheaper and faster way to produce these components could make it less expensive to connect everyday objects -- from clothing to household appliances -- to the internet, advancing the concept known as the Internet of Things. The micromanipulation technique might also be used to create a safer and faster-charging replacement for mobile device batteries.
Optical traps, which use light to hold and move small objects in liquid, are a promising non-contact method for assembling electronic and optical devices. However, when using these traps for manufacturing applications, the liquid must be removed, a process that tends to displace any pattern or structure that has been formed using an optical trap.
In The Optical Society (OSA) journal Optics Express, researchers in Steven Neale's Micromanipulation Research Group, University of Glasgow, Scotland, detail their method for using an advanced optical trapping approach known as optoelectronic tweezers to assemble electrical contacts. Thanks to an innovative freeze-drying method developed by Shuailong Zhang, a member of Neale's research group, the liquid could be removed without disturbing the assembled components.
"The forces formed by these optoelectronic tweezers have been compared to Star-Trek like tractor beams that can move objects through a medium with nothing touching them," said Neale. "This conjures up images of assembly lines with no robotic arms. Instead, discrete components assemble themselves almost magically as they are guided by the patterns of light."
The researchers demonstrated the technique by assembling a pattern of tiny solder beads with an optoelectronic trap, removing the liquid, and then heating the pattern to fuse the beads together, forming electrical connections. They used the solder beads to demonstrate that in the future, these microparticles could be assembled and fused to create electrical connections.
"Optoelectronic tweezers are cost-effective and allow parallel micromanipulation of particles," said Zhang, who is now at the University of Toronto in Canada. "In principle, we can move 10,000 beads at the same time. Combining this with our freeze-drying approach creates a very inexpensive platform that is suitable for use in mass production."
Improved electronics manufacturing
The new technique could offer an alternative way to make the circuit boards that connect the components found in most of today's electronics. These types of devices are currently made using automated machines that pick up tiny parts, place them onto the circuit board and solder them into place. This process requires an expensive motorized stage to position the board and a costly high-precision robotic arm to pick up and place the tiny parts onto the device. The cost of these micromanipulation systems continues to rise as the shrinking size of electronics increases precision requirements.
"The optoelectronic tweezers and freeze-drying technique can be used to not only assemble solder beads, but also to assemble a broad range of objects such as semiconductor nanowires, carbon nanotubes, microlasers and microLEDs," said Zhang. "Eventually, we want to use this tool to assemble electronic components such as capacitors and resistors as well as photonic devices, such as lasers and LEDs, together in a device or system."
Trapping particles with optoelectronic manipulation
The researchers used optoelectronic tweezers because this optical manipulation approach can form thousands of traps at once, offering the potential of massively parallel assembly. The tweezers are formed using a layer of silicon that changes its electrical conductivity when exposed to light. In the areas exposed to points of light, a non-uniform electric field forms that interacts with particles or beads in a liquid layer on top of the silicon, allowing the particles to be precisely moved by moving the point of light. Creating patterns of light points allows multiple particles to be moved simultaneously.
"Using our method, we can move solder beads measuring from the nanometer range up to about 150 microns," said Zhang. "We have been able to move objects that are over 150 microns, but it's more challenging because as the size of the object increases, the frictional force also increases."
After using the optoelectronic tweezers to assemble a pattern of 40-micron-diameter, commercially available solder beads, the researchers froze the liquid in the optoelectronic tweezer device and then reduced the surrounding pressure to allow the frozen liquid to turn from a solid directly into a gas. This freeze-drying approach allowed the assembled solder beads to remain fixed in place after the liquid was removed. The researchers say it can be used to remove liquid used with any type of optical trap, or even traps formed with acoustic waves.
In addition to assembling the solder beads into different lines, the researchers also demonstrated parallel assembly of several beads and used the beads to form electrical connections. The solder beads exhibit a strong dielectric force, which means they can be moved accurately and fast, allowing very efficient assembly of structures.
The researchers are now working to turn their laboratory-based system into one that would combine the optoelectronic tweezer and freeze-drying process in a single unit. They are also developing a software interface to control the generation of a light pattern based on the number of particles that needed to be trapped.
"We are now using a computer to generate the light pattern to move the beads, but we are working on an app that would allow a tablet or smart phone to be used instead," said Zhang. "This could allow someone to sit away from the system and use their finger to control the movements of the particles, for example."
Neale recently received funding to continue this line of research by using the new optical micromanipulation approach to create high energy density capacitors to replace batteries in mobile devices.
Paper: S. Zhang, Y. Liu, Y. Qian, W. Li, J. Juvert, P. Tian, J.-C. Navarro, A.W. Clark, E. Gu, M.D. Dawson, J.M. Cooper, S.L. Neale, "Manufacturing with light - micro-assembly of opto-electronic microstructures," Opt. Express, Volume 25, Issue 23, 28838-28850 (2017). DOI: 10.1364/OE.25.028838.
About Optics Express
Optics Express reports on new developments in all fields of optical science and technology every two weeks. The journal provides rapid publication of original, peer-reviewed papers. It is published by The Optical Society and edited by Andrew M. Weiner of Purdue University. Optics Express is an open-access journal and is available at no cost to readers online at: OSA Publishing.
About The Optical Society
Founded in 1916, The Optical Society (OSA) is the leading professional organization for scientists, engineers, students and business leaders who fuel discoveries, shape real-life applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership initiatives, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of optics and photonics experts. For more information, visit osa.org.
Joshua Miller | EurekAlert!
A 'virtual wall' that improves wireless security and performance
08.11.2017 | Dartmouth College
Quantum computing on the move
06.11.2017 | Johannes Gutenberg-Universität Mainz
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
The Fraunhofer Institute for Laser Technology ILT and Rapid Shape GmbH are working together to further develop resin-based 3D printing. The new “TwoCure” process requires no support structures and is significantly more efficient and productive than conventional 3D printing techniques for plastic components. Experts from Fraunhofer ILT will be presenting the state-funded joint development that makes use of the interaction of light and cold in forming the components at formnext 2017 from November 14 to 17 in Frankfurt am Main.
Much like stereolithography, one of the best-known processes for printing 3D plastic components works using photolithographic light exposure that causes liquid...
A team of researchers led by Prof. Wolfram Pernice from the Institute of Physics at Münster University has developed a miniature abacus on a microchip which calculates using light signals. With it they are paving the way to the development of new types of computer in which, as in the human brain, the computing and storage functions are combined in one element.
Researchers at the universities of Münster, Exeter and Oxford have developed a miniature “abacus” which can be used for calculating with light signals. With it...
30.10.2017 | Event News
23.10.2017 | Event News
17.10.2017 | Event News
08.11.2017 | Awards Funding
08.11.2017 | Earth Sciences
08.11.2017 | Information Technology