Researchers Create Lens to Turn Smartphone into Microscope

a) Changing the temperature of the preheated surface modifies the shape of a cured lens. b) The inkjet print head printing droplet lenses on a heated surface, and c) The lens can be attached to a smartphone for microscopy applications.

Lens Could Give Schools, Clinics Low-Cost Alternative to Conventional Equipment

Researchers at the University of Houston have created an optical lens that can be placed on an inexpensive smartphone to amplify images by a magnitude of 120, all for just 3 cents a lens.

Wei-Chuan Shih, assistant professor of electrical and computer engineering at UH, said the lens can work as a microscope, and the cost and ease of using it – it attaches directly to a smartphone camera lens, without the use of any additional device – make it ideal for use with younger students in the classroom.

It also could have clinical applications, allowing small or isolated clinics to share images with specialists located elsewhere, he said.

In a paper published in the Journal of Biomedical Optics, Shih and three graduate students describe how they produced the lenses and examine the image quality. Yu-Lung Sung, a doctoral candidate, served as first author; others involved in the study include Jenn Jeang, who will start graduate school at Liberty University in Virginia this fall, and Chia-Hsiung Lee, a former graduate student at UH now working in the technology industry in Taiwan.

The lens is made of polydimethylsiloxane (PDMS), a polymer with the consistency of honey, dropped precisely on a preheated surface to cure. Lens curvature – and therefore, magnification – depends on how long and at what temperature the PDMS is heated, Sung said.

The resulting lenses are flexible, similar to a soft contact lens, although they are thicker and slightly smaller.

“Our lens can transform a smartphone camera into a microscope by simply attaching the lens without any supporting attachments or mechanism,” the researchers wrote. “The strong, yet non-permanent adhesion between PDMS and glass allows the lens to be easily detached after use. An imaging resolution of 1 (micrometer) with an optical magnification of 120X has been achieved.”

Conventional lenses are produced by mechanical polishing or injection molding of materials such as glass or plastics. Liquid lenses are available, too, but those that aren’t cured require special housing to remain stable. Other types of liquid lenses require an additional device to adhere to the smartphone.

This lens attaches directly to the phone’s camera lens and remains attached, Sung said; it is reusable.

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