Optical Aerosol Transport Sensor

Aerosol-jet printing (AJP) is an important emerging additive manufacturing (AM) technology for constructing electronic devices and systems, such as circuit boards. But there are key challenges: resolution and feature density limitations; lower yield predictability; reliability; and device performance. This technology provides controls for stabilizing or manipulating the AJP outcomes in real time. The invention provides a method to infer physical properties of aerosolized ink before it has been deposited on a target substrate. Properties include aerosol refractive index and particle distribution parameters including number density and diameter distribution.

Description

AJP is a direct-write additive electronics manufacturing process with high resolution and the ability to print on 3D surfaces, but is limited in yield and has high costs. Its low predictability in an open-loop process produces high variation and low yield. This technology enables closed-loop processing, where controls can be updated in real time. This technology utilizes a low-cost optical spectrometer to monitor the properties of the aerosol stream that deposits the ink. This provides information on stream density, droplet distribution, and material properties of the stream. These properties determine how much material is being deposited using an aerosol, as well as the kinetics of material deposition which determine factors including line and edge definition. Typical printing in this realm requires manual oversight, but this technology will enable real time controls, eliminating that need, and allow for extended printing runs without interruption. Using LEDs and photodiodes, the invention relies on measuring the pattern of light scattering at only a few wavelengths, but at numerous scattering angles. This enables the inference of the aerosol’s optical properties and droplet distribution, from scattering measurements.

Benefits

• First of its kind to monitor with sensitivity to aerosol droplet distribution 
• Less costly
• Provides multiple scattering angles
• Enables real time control
• Can run for extended periods continuously 
• Reduces need for manual oversight
• Increases reliability and yield
• Provides knowledge of variables determining line morphology

Applications and Industries

• Printing for additive manufacturing
• Consumer electronics
• Antennas for wireless devices

Contact

To learn more about this technology, email partnerships@ornl.gov or call 865-574-1051.