3D inkjet printing of optical elements

Highly individualized micro- and macro-optical components and systems

Additively manufactured micro- and macro-optics and optical systems open up new possibilities in development processes such as rapid prototyping or in the production of individualized small series. With 3D inkjet printing of optical elements, Fraunhofer IOF is developing solutions for the optics production of the future. The additive process not only enables the cost-effective production of individualized optical components. The compatibility of the process with numerous functional materials also opens up new possibilities in the production of highly integrated optical systems.

At Fraunhofer IOF, the entire process chain is investigated and developed, from the pre-treatment of the substrates and the development of the printing process, to the targeted post-treatment of the printed structures. Our many years of experience lead to a targeted parameter optimization of the entire printing process.

Our range of services

We realize tailor-made solutions for our customers with the development of single processes and process chains in the field of 3D printing of optical systems. Our range of services includes the selection of suitable materials and the development of inks, the development of targeted substrate preparation processes, the development of printing processes for the various materials and inks, as well as the targeted post-treatment of printed structures. In addition, extensive optical, electrical, and mechanical characterization of the printed structures is carried out at the customer's request.

Your advantages of working with us

 

We develop highly customized feature integrations on a variety of materials using inkjet printing technology.

The combination of our experience and passion for challenging technological boundaries enables us to develop exceptional, customized multilayer and multi-material functionalities on a variety of substrates.

Inkjet-printed microlens arrays.
© Fraunhofer IOF
Inkjet-printed microlens arrays.
Printed freeform optics for light field shaping.
© Fraunhofer IOF
Printed freeform optics for light field shaping.
Printed optical components can be equipped with different functionalities. Here: optical component with integrated LED.
© Fraunhofer IOF
Printed optical components can be equipped with different functionalities. Here: optical component with integrated LED.

Our range of printable materials

 

  • ORMOCER® - Organic/inorganic hybrid polymers
    • High thermal / mechanical / chemical stability
  • Acrylates
    • Tailored refractive index
  • Silver / Gold / Graphite
    • Optical mirrors
    • Wiring / electrodes
  • Various functional polymers
    • Light filters, baffles, absorbers

The advantages of our 3D printing technology at a glance

 

  • Cost-effective material application
  • Digital printing technology
    • Material savings
    • Easy design changes
    • Capability of rapid prototyping
  • Mask-free, contactless deposition
  • Deposition at normal atmosphere
  • Processing at room temperature
  • Compatible with substrates of glass, polymers, and paper

Technical equipment in the field of 3D inkjet printing

 

  • For cleaning and activation of various substrates (glass, plastics, metal, ceramics, paper) we have a wet chemical cleaning line and plasma ovens.
  • For printing, we use commercial inkjet printers in desktop format.
  • The use of laminar flow box modules enables almost particle-free printing results.
  • Inks that require an inert atmosphere are printed in a nitrogen atmosphere with the exclusion of oxygen and water.
  • The use of different industrial print heads from renowned manufacturers enables us to use a wide range of inks in a large viscosity range.
  • Heatable substrate tables lead to an optimized printing result. UV lamps with different wavelengths allow curing of UV-crosslinking materials.
  • For post-treatment we use heating and plasma ovens as well as vacuum chambers to achieve the desired properties.

Our research strength

 

Articles of the annual report

The articles in the annual report show, among other things, the research strength of our experts at Fraunhofer IOF. Every year, selected research results from the previous year (archive annual reports) are published in the annual report. You can find the articles on the developments of inkjet printing from the past years in the following list:

 

Excellent scientific publications

A large number of scientific results are published by our researchers in scientific journals. A list of scientific papers on 3D inkjet printing can be found below:

Selection of scientific publications

Markets and applications for 3D printed optical elements

3D inkjet printing of optical elements is interesting for many applications and especially for the production of small series and individualized products. At Fraunhofer IOF, applications are already being developed in the fields of medical technology, life sciences and the automotive industry. Inkjet printing enables flexible solutions for the challenges of our customers.

In various projects, tailor-made micro- and macro-optical components and systems for use as illumination and imaging optics have been realized at Fraunhofer IOF. The fully 3D inkjet printed functionalities include:

  • LED lightguides
  • Optical waveguides
  • Freeform refractive optics for illumination
  • Microlens arrays

In addition to the applications mentioned above, Fraunhofer IOF is also working on 3D printing of eyeglasses (more info below).

Optical components (e.g., freeforms, lenses) produced by 3D inkjet printing for various applications.
© Fraunhofer IOF
Optical components (e.g., freeforms, lenses) produced by 3D inkjet printing for various applications.

Everything important at a glance

 

Find the important information summarized in our handy data sheet on the subject of 3D-printed optics.

More questions?

 

Please ask us. We are happy to help you.

If you have any questions about collaborating with Fraunhofer IOF, you can find more information by clicking on the following link:

 

Have we sparked your interest?

 

Please contact us.

We develop customized solutions for photonic problems from industry and science.

Further information

 

A selection of scientific results in the field of 3D inkjet printing

Eyeglasses inkjet printed at Fraunhofer IOF.
© Fraunhofer IOF
Eyeglasses inkjet printed at Fraunhofer IOF.

InkEye - 3D polymer printing of eyeglasses

Optical components are manufactured conventionally by milling, grinding, and polishing molded or replicated polymer- and glass preforms. For cost-effective production, such optics need to be fabricated with simple geometries in large lot sizes. However, in modern optics production, small lot sizes and even individual optics have become more and more important. This trend is established already in eyeglass manufacturing, where every glass is individualized to the person wearing it. With the inkjet printing of eyeglasses, an additive manufacturing strategy was developed at Fraunhofer IOF. Because of its digital character, this technique enables the cost-effective manufacturing of individualized freeform optics and even the deposition of further functional coatings. Within the “InkEye” project, the capabilities are demonstrated by fully inkjet printing eyeglasses with a scratch-resistant coating.

To manufacture the eyeglasses, a mixture of cross-linkable acrylates with low viscosity is deposited in a multilayer inkjet process. Each printed layer has to be UV-cured to crosslink the polymer ink and to guarantee the mechanical stability of the single layers. With each printing run, a 3 μm to 10 μm thick layer is applied. Thus, macroscopic optical components consist of many hundreds of layers. By tailoring the process management and the process parameters, the cross-linking reaction and thus the polymerization of the polymer can be controlled at the surface and interfaces. Therefore, highly precise and very homogeneous optics can be manufactured with inkjet printing.

As a final step, the scratch-resistant coating is printed onto the eyeglass. This increases abrasion resistance, which guarantees durability during mechanical cleaning. The dimensional accuracy of the surface achieved is in the range of PV < 150 nm with a surface roughness of < 3 nm RMS. The refractive index of the printed acrylate mixture was tailored to > 1.54 by achieving transmission of > 90 % of the resulting printed eyeglasses. In addition, the material has a glass transition temperature of > 80 °C. All these properties are essential requirements for the use of the material in eyeglass manufacturing.

The inkjet printing process developed enables the manufacturing of eyeglasses with high quality and properties comparable to modern requirements.

 

Authors: Falk Kemper, Erik Beckert, Maximilian Reif, Lisa Pohle, Thomas Schönfelder

Fig. 1: Integrated functionalities (LEDs, baffles, inkjet printed silver mirrors) in fully inkjet printed 3D-Ormocomp®-structures.
© Fraunhofer IOF
Fig. 1: Integrated functionalities (LEDs, baffles, inkjet printed silver mirrors) in fully inkjet printed 3D-Ormocomp®-structures.
Fig. 2: Fully inkjet printed optical components made of Ormocomp®.
© Fraunhofer IOF
Fig. 2: Fully inkjet printed optical components made of Ormocomp®.

3D-inkjet printing of optical components

Micro and macro optical components are conventionally manufactured using milling or molding techniques of polymers and glasses. The fabrication of medium and large lot sizes is very cost efficient with these techniques. However, for cost effective manufacturing of single individualized optics, they are not suitable. To overcome this issue, inkjet printing of Ormocers® is being introduced at Fraunhofer IOF. This digital manufacturing technique is very flexible, provides a high freedom of design, and thus enables the fabrication of such highly individualized three-dimensional micro- and macro optical components.

For fully inkjet printing 3D-optical components, Ormocomp®, a hybrid organic-inorganic polymer, is used. It combines beneficial properties of organic and inorganic materials. Its processability is comparable with conventional polymers. However, it has a higher chemical, mechanical, and thermal stability because of its inorganic components. In addition, it shows a very high optical transparency in the complete visible spectrum. Therefore, Ormocomp® is highly suitable for the manufacturing of robust 3D-optics.

The 3D-Ormocomp® components are manufactured using a commercial inkjet printer. The structures are sliced and printed layer-by-layer. Each printed layer of low viscous ink has to be UV-cured in order to crosslink the polymer ink and to guarantee mechanical stability of the single layers. With each printing run, a 3 μm to 10 μm thick layer is applied. Thus, macroscopic optical components consist of many thousands of layers.

By optimizing the resolution of the printed layers, the UV-curing conditions, and adapting the printed designs, high dimensional accuracies of the 3D-components could be achieved. The resulting surface roughness of macro optics is in the range of < 60 nm with a PV < 20 μm. With these parameters, the optics are suitable for the use in lighting applications. Figure 2 shows some examples of fully inkjet
printed 3D-optical components made of Ormocomp®. Because of the additive manufacturing approach, a further functionalization of the printed optics is possible. Figure 1 shows integrated LEDs with printed conductive tracks, integrated baffles and inkjet printed silver mirrors in fully inkjet printed three-dimensional optics.

The potential of the introduced technique lies in its use for rapid prototyping and the manufacturing of individualized components with very small lot sizes.

 

Authors: Falk Kemper, Maximilian Reif, Lisa Pohle, Thomas Schönfelder, Erik Beckert

Inkjet printing of functional materials

Using inkjet printing technology, we develop highly individual 2D structures on various materials at Fraunhofer IOF.

Inkjet printing of functional materials

Opto-mechatronical components and systems

Get an overview of the entire range of services offered by our scientific department “Opto-mechatronical Components and Systems” at Fraunhofer IOF.

Overview

Additive Manufacturing of metal optics

At Fraunhofer IOF, technologies are being developed for the additive manufacturing of high-performance metallic components using selective laser melting.

Additive Manufacturing of metal optics