New technology makes 3D microscopes easier to use, less expensive to manufacture

Traditional, large depth-of-field 3D microscopes are used across academia and industry, with applications ranging from the life sciences to quality control processes used in semiconductor manufacturing. Song Zhang, professor in Purdue's School of Mechanical Engineering, said they are too slow to capture 3D images and too expensive to build due to the requirement of a high-precision translation stage.

"Such drawbacks in a microscope slow the measurement process, making it difficult to use for applications that require high speeds, such as in situ quality control," Zhang said.

Research about the Purdue 3D microscope and its innovations has been published in the peer-reviewed Optics Letters and the August 2023 and March 2024 issues of the peer-reviewed Optics and Lasers in Engineering. The National Science Foundation awarded a grant to conduct the research.

The Purdue innovation

Zhang said the Purdue 3D microscope automatically completes three steps: focusing in on an object, determining the optimal capture process and creating a high-quality 3D image for the end user.

"In contrast, a traditional microscope requires users to carefully follow instructions provided by the manufacturer to perform a high-quality capture," Zhang said.

Zhang and his colleagues use an electronically tunable lens, or ETL, that changes the focal plane of the imaging system without moving parts. He said using the lens makes the 3D microscope easier to use and less expensive to build.

"Our suite of patents covers methods on how to calibrate the ETL, how to create all-in-focus 3D images quickly and how to speed up the data acquisition process by leveraging the ETL hardware information," Zhang said. "The end result is the same as a traditional microscope: 3D surface images of a scene. Ours is different because of its high speed and relatively low cost."

The next developmental steps

Zhang and his team have developed algorithms and created a prototype system in their lab. They are looking to translate their research into a commercial product.

"This will require an industrial partner," Zhang said. "We are certainly interested in helping this process, including sharing our know-how and research results to make the transition smooth."

Zhang disclosed the innovations to the Purdue Innovates Office of Technology Commercialization, which has applied for and received patents to protect the multiple pieces of intellectual property.