Salt Grain-Sized Cameras Can Travel Inside Body

Alyssa Danigelis

THE GIST

German engineers have created the smallest microcameras of their kind.

The new inexpensive disposable cameras can be produced 25,000 at a time.

The microcamera's applications include medical and automotive imaging.

A new camera is as small as a coarse grain of salt -- the tiniest of its kind. This microcamera could go far: traveling deep into the human body to reveal hidden nooks and crannies. And it could be used in cars to keep drivers safe.

"I have it here on the desk," said Michael Töpper, project manager at the Fraunhofer Institute for Reliability and Microintegration in Berlin, the large German R&D facility that worked on the device. "If you look at the camera, it's hard to believe that this is working."

Fraunhofer developed the camera with the specialized image sensor company Awaiba, which sought to improve miniaturized cameras for medical applications. Current microcameras require individual, manual manufacturing techniques that have kept costs high. Töpper and his colleagues developed a method to assemble the cameras on a single wafer using specialized polymers to bond the parts.

"The last step is then dicing the image sensor into individual camera chips," he said.

Each of the three sides of the camera measures a mere 1 millimeter. One wafer can be used to assemble 25,000 lenses on 25,000 cameras. The resulting resolution for each of the miniature cameras is in the range of 25,000 pixels. While that's not high enough for a professional photographer, it is high for medical applications, Töpper said..

More efficient manufacturing means lower costs, and the microcameras themselves are disposable. Töpper points to a process for sterilizing reusable endoscopic cameras, saying that usually involves lots of chemicals. Although the new microcameras are not recyclable, he says that they are primarily made from silicon and glass. "There are no hazardous materials."

In medicine, gastroenterologists regularly use small cameras to check patients. Colon cancer is the second leading cause of cancer death, resulting in 150,000 cases every year, according to Dr. Gregory Cooper, a Case Western Reserve University professor of medicine and oncology, and gastroenterologist at University Hospitals Case Medical Center.

"Most colon cancers are thought to be preventable if the patient has a colonoscopy," he said.

Screening for polyps and colorectal cancer can involve a fairly invasive double-balloon endoscope requiring sedation, or a large swallowable "pill cam" that sometimes moves through a 25-foot small bowel too fast to capture all the information.

Dr. Cooper said he thinks the Fraunhofer microcamera technology looks interesting, although he notes that a scope used with the disposable camera would still need sterilization.

"If it can get around some of the current limitations of endoscopy, i.e. the sedation and the need to sterilize things, the limited visualization of the small bowel -- I think it has promise," he said.

At the moment Awaiba is testing the devices, and plans to put the microcameras into production within the next two years, Töpper said. Beyond medicine, the cameras could serve a useful purpose in the automotive industry. Installing them in cars might make camera-assisted parking more ubiquitous, and they could also help monitor drivers who risk falling asleep at the wheel.

"If you think about very, very small cameras, you will find dozens of applications," Töpper said. "Just think about the camera in the phone: 10 years ago everybody was laughing. 'Who needs a camera in a phone?'"

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