Researchers have developed an inkjet printing technique that can be used to print optical components such as waveguides. Because the printing approach can also fabricate electronics and microfluidics, it could advance a variety of devices such as optical sensors used for health monitoring and lab-on-a-chip devices that integrate and automate multiple laboratory functions onto a small circuit, or chip.
“Inkjet printing is a very attractive method for fabricating optical components because the positions and sizes of features can easily be modified and there is virtually no material waste,” said FabianLütolf, a member of the research team led by Rolando Ferrini at CSEM in Switzerland. “However, the surface tension of the inks makes it difficult to print lines with a specific height, which is necessary to create a waveguide.”
Inkjet printing is an additive manufacturing technique that uses tiny nozzles like the ones found in desktop inkjet printers to deposit a computer-generated pattern of drops (the “ink”) onto a substrate to build a structure. The researchers discovered that depositing the ink in two steps, rather than the traditional single step, enabled printing of lines with a specific height and with much smoother features than would otherwise be possible. The printed structures are considered to have 2.5 dimensions because although they are not flat, their complexity is limited compared to structures created with traditional 3D printing.
In The Optical Society (OSA) journal Optics Express, the researchers show that their technique can be used to print 2.5D optical waveguides and tapers made of acrylic polymer. The printing concept can also be used with other materials such as metallic inks to make electronics or sucrose mixtures for biodegradable applications.
Lütolf points out that although printing of electronics is already used commercially, printing microfluidics is more challenging and prone to the same problems as waveguides. “The fact that our approach could allow components with multiple functionalities to be fabricated with a single printer paves the way toward additive manufacturing of entire integrated circuits on chips,” said Lütolf. “This means that optical components could be added to flexible hybrid electronics and that optoelectronic components such as light sources or detectors could be integrated into printed optical circuits.”
Turning a problem into a solution
Because of surface tension, inks deposited on a substrate tend to bulge or split. Depositing the ink in two steps allowed the researchers to turn the surface tension of the liquid into an advantage. After depositing a series of droplets, the ink printed in the second step seeks to minimize its surface energy by self-aligning between the droplets from the first print. Unlike previous inkjet printing approaches, the researchers did not have to pre-pattern the substrate, which increases the available design space and simplifies fabrication.
To carry out the new technique, a series of droplets called pinning caps are first printed. These spherical caps pin liquid bridges formed by the ink from the second print, forming a configuration that immobilizes the ink and prevents the formation of bulges in the printed line. In addition to making straight lines between two dots, the technique can be used to connect three or more junctions to make corners or sharp edges.
The new technique offers several advantages over classical photolithography, which is typically used to make tiny components on chips. “Inkjet printing doesn’t require a physical mask like photolithography and it is easier to connect components,” said Lütolf. “Also, if you just want to quickly test an idea or vary a parameter, additive manufacturing methods such as inkjet printing only require adaption of the digital design.”
To evaluate the new printing method, the researchers created a polymer waveguide that was 120 microns wide and 31 microns tall with a taper that allowed light from an external laser source to enter the waveguide. They measured the optical loss within the waveguide to be 0.19 dB/cm, only an order of magnitude higher than state of the art waveguides created using photolithography.
“In the paper, we report the first inkjet-printed waveguides with loss characterization,” said Lütolf. “For the applications we envision, the waveguides would carry light for short distances, and not across entire networks. The current level of losses can be tolerated for such applications.”
According to the researchers, the smallest possible waveguides consists of a single droplet of ink, the size of which is limited by the nozzle of the inkjet printer. For the printer used in the study, the narrowest waveguides would be in the 40-micron range with a height of around 10 micrometers. Typical industrial inkjet printers also have similar limits.
“With our current combination of materials and hardware, it’s not possible to make waveguides below 10 micrometers, as typically required for single mode operation. But we are close,” said Lütolf. “There is, however, no fundamental physical limit that would prevent us from printing single mode waveguides.”
He adds that several groups have demonstrated printing capabilities in the submicron range with techniques such as electrohydrodynamic printing (E-jet). It should be possible to combine such instruments with the new inkjet printing technique to create single mode waveguides.
The researchers are now working to optimize the printing method and the ink to further lower the amount of light lost by the waveguide. They are also working to make the inkjet process more applicable for large-scale fabrication and, eventually, commercial implementation.
The Latest on: Additive manufacturing
via Google News
The Latest on: Additive manufacturing
- Stratasys Direct Manufacturing Adds VELO3D’s Sapphire 3D Printer to Its Metals Portfolio on April 17, 2019 at 11:46 pm
In order to help companies tackle more difficult projects with metal 3D printing, Stratasys Direct Manufacturing (SDM), a Stratasys subsidiary and one of North America’s largest additive and ... […]
- Manufacturing Market Trends April 2019, Issue 1 on April 17, 2019 at 4:18 pm
Additive Manufacturing. Additive manufacturing, the process of building three-dimensional structures by adding layers of material through digital design, is no longer just wishful thinking; the number ... […]
- Introducing serial additive manufacturing into the automotive industry on April 17, 2019 at 1:43 pm
The BMW Group has launched what promises to be a landmark project for the introduction of serial additive manufacturing into the automotive industry. Named the “Industrialization and Digitization of ... […]
- Why the Executive Perspective Is Essential for Adopting Additive Manufacturing on April 17, 2019 at 5:05 am
We report often about additive manufacturing and its opportunities for processors in the market. While AM continues to evolve into production, there is much to consider beyond manufacturing parts. ... […]
- When Additive Manufacturing Goes Beyond "Manufacturing" on April 17, 2019 at 2:03 am
Additive manufacturing (AM) is sometimes discussed in contrast to “subtractive manufacturing,” but that’s not entirely accurate. Thinking in terms of additive versus subtractive sets up an unhelpful ... […]
- Innovations in Additive Manufacturing and Robots, 2019 Study - ResearchAndMarkets.com on April 16, 2019 at 7:41 am
DUBLIN--(BUSINESS WIRE)--The "Innovations in Additive Manufacturing and Robots" report has been added to ResearchAndMarkets.com's offering. This Advanced Manufacturing Technology TechVision ... […]
- New Metal Additive Manufacturing Technology Coming to the Aerospace Market on April 16, 2019 at 3:16 am
Advanced manufacturing (AM) is becoming increasingly important in the highly competitive aerospace market—and two leaders in the AM field, 3M and GF Machining Solutions, have developed a new ... […]
- CRP: producing excellence with additive manufacturing technology and high-performance materials on April 16, 2019 at 2:29 am
Since the mid-90’s, CRP Technology (headquartered in Modena, Italy) has been changing the rules of manufacturing. Most in the manufacturing Industry may have only discovered the world of ... […]
- Collins Eyes 20 Additive Manufacturing Parts This Year on April 12, 2019 at 11:30 am
ATLANTA--Collins Aerospace is taking the next step with its aerospace additive manufacturing activity, with aspirations to develop 20 production-ready metal parts in 2019, says Paula Hay, the ... […]
via Bing News