Scientists have known for centuries that sound waves make ripples in the water. They have also known that shining light through a lens can focus it. But it wasn’t until Princeton engineering professor Craig B. Arnold came along that these two fundamental properties of nature were put together by an invention that has found uses in machine vision, advanced imaging for medicine, self-driving cars, and other areas of technology.
Arnold’s invention has only recently hit the marketplace, but its roots go back to when he was a graduate student at Harvard, working on a project in which he was using sound waves to change the shape of a liquid in an attempt to bend a laser beam. After years of experimentation he realized that this technique could be used to create a lens that could be re-focused in less than a millisecond.
Think of the way the human eye focuses its lens: muscles attached to the lens expand and contract, changing its shape and therefore changing its focus. Transparent liquid can also act as a lens, and sound waves can be used to change its shape. By doing this you can change the shape of a liquid lens just as quickly as you can change the sound going into it, which is nearly instantly. “It took a few years to figure out how to make this work in a way that produced a nice, simple lens like your eye,” Arnold says. “Once we did it became clear how we could use it.”
Arnold’s invention is an example of successful technology commercialization: a product that came out of lab science, proved valuable to industry, and was made into a commercial product. On Wednesday, March 14, Princeton’s Keller Center will hold its 13th annual Innovation Forum, a competition in which researchers pitch their own creations to a panel of judges that includes experienced venture capitalists. The event will take place from 2:30 to 6:15 p.m. at the Carl Fields Center. Arnold will be the keynote speaker.
Arnold grew up in Long Island, where his father was a truck driver who founded AD Richards, a company that rents out shipping containers. He went to Haverford College before getting his doctorate in physics at Harvard and doing post-doctorate work at the Naval Research Labs in Washington.
It took years for the insights that Arnold developed during his education to come together and pay off in his idea for rapid optics. But when it did Arnold knew he had a potentially money-making invention on his hands. He also knew his limitations. He had spent his whole career in school and had no handle on the business world. So he teamed up with a partner who was an expert where he had little knowledge.
“The team is so critically important,” Arnold says. “You could have the best tech in the world, and it will get nowhere if you don’t have the right group of people to bring it to the forefront. Unfortunately, scientists think they can do everything, but they can’t. And businesspeople think they can violate all laws of physics whenever you need to, and you can’t.”
Arnold’s partner, Christian Theriault, was no slouch when it came to technical details either. He had both undergraduate and graduate degrees in engineering from Princeton, and had spent two-and-a-half years in business and corporate development at a healthcare startup. “He helped teach me as much about business as much as I taught him about optics and optical technology,” Arnold says. “It was a really great learning experience.”
Together the pair founded TAG Optics on Harrison Street in Princeton to manufacture their lenses, which have unique capabilities. While conventional lenses can only focus on objects at a certain distance, TAG’s lenses, which have no moving parts, can change their focus thousands of times per second, allowing imaging with much greater depth of field.
For example, a beverage bottle factory might have a camera-assisted inspection system to look at bottles for flaws. Typical cameras would have to either focus on the neck of the bottle, or the bottom, or pause to switch back and forth between the two. TAG’s cameras could look at both at once.
In 2016 Mitutoyo Corporation, based in Kawasaki, Japan, bought TAG Optics — a successful exit for the founders.
The Innovation Forum will feature a host of promising-seeming inventions. Most likely, some will succeed, and some will be forgotten. The difference between the two may well be in how savvy the inventors are in promoting their products.
“Whenever I hear about the latest-and-greatest whatever, I think, ‘I wish I had thought of that,’” Arnold says. “But so much hard work goes into it from the press release to actually making money off of the technology. That stuff is not so sexy. It’s sleepless nights and ‘how do we fix this one little problem’ and ‘how do we get this piece of paper on the right person’s desk.’ That’s not exciting stuff.”