Lenses That Move Sideways Could Improve Smartphone Snaps

 

Startup DynaOptics uses lenses that move from side to side, rather than forward and backward, for a high-quality optical zoom in smartphones.

• By Rachel Metz on October 3, 2014

Why It Matters

Many of us use a smartphone instead of a point-and-shoot camera, but a good optical zoom feature is still missing.

The CEO of DynaOptics, Li Han Chan, holds the development kit.

To pack a camera-quality optical zoom into a smartphone that’s still slender enough to fit into the pocket of some skinny jeans, a startup is building lenses that magnify by moving from side to side, rather than forward and backward.

Due in part to space constraints, most smartphone cameras rely on digital zoom, which uses software to simply blow up whatever the lens is focused on. This technique can result in pixilated photos. Optical zoom, in contrast, increases the distance between the lens and the image sensor, magnifying the details of the photo subject in a way that renders a clearer close-up.

DynaOptics says its optical zoom feature could be added to smartphone cameras without making handsets overly bulky. It uses a kind of progressive lens similar to what you see in bifocals, and moves them in an overlapping fashion from side to side to change zoom.

CEO and cofounder Li Han Chan says the company aims to have samples of its lenses ready for testing early next year. Assuming the tests go well, she says, phones featuring the lenses could be available by the end of 2015 or in early 2016. The components will cost several dollars apiece, Chan adds.

Many people have replaced point-and-shoot cameras with smartphones, but optical zoom is among the few key features that haven’t yet migrated over. “If you believe the vision that nobody’s ever going to have to carry two devices around again, that’s natural,” Chan says.

Chan showed me a DynaOptics lens in the palm of her hand. It’s a tiny rectangle of plastic that, unlike a regular curved lens, is part concave, part convex. Several of these lenses (Chan wouldn’t say how many) are packed within the company’s latest lens module prototype: a small black square about the size and thickness of a couple of stacked Scrabble tiles with an aperture on one side. This lens module, which also contains a simple electric motor, was connected to a box containing an image sensor, which was itself tethered to a laptop running the DynaOptics software.

The whole contraption faced a sort of checkerboard held up on its side. When Chan pressed a button on a connected remote control, the lenses moved sideways to overlap in predetermined positions, and a fuzzy, darkened image of the checkerboard shown on the laptop display immediately enlarged.

For now, the DyanOptics lens prototypes can magnify objects up to three times larger than they really are. Chan says the company expects to magnify objects up to five or six times—any higher might require the lens module to be larger.

The image quality, as I could see, still needs a lot of work; Chan freely admitted it’s “not that great yet.” DynaOptics needs to fine tune the lenses to improve it, she says.

Allen Yi, a professor at Ohio State University who has studied the kind of lenses used by DynaOptics, can see the appeal of optical zoom on a smartphone camera. and suspects others would, too. But he’s not sure how easy it will be for DynaOptics to create a reliable, robust lens system within the confines of a smartphone. “Whether they can actually get everything in a compact form and still work to the performance you need, I’m not really sure,” he says.

Chan is already thinking beyond the smartphone. She believes the technology could find a home in the cameras strapped to drones or robots. “We started with the mobile phone because that was the most applicable area for this technology, but there are cameras everywhere,” she says.

'Smart glass' micro-iris for smartphone cameras

 

June 18, 2014

Institute of Physics

A small, low-powered camera component made from a 'smart glass' material has been created by a group of researchers in Germany with the hope of inspiring the next generation of smartphone cameras. The micro-iris is an electro-chemical equivalent to the bulky, mechanical blades that are usually found in cameras and has very low power consumption, making it an ideal component for a wide-range of camera-integrated consumer devices.

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The micro-iris is an electro-chemical equivalent to the bulky, mechanical blades that are usually found in cameras and has very low power consumption, making it an ideal component for a wide-range of camera-integrated consumer devices.

The device and the first results of its performance have been presented in a study published today, 19 June, in IOP Publishing's Journal of Optics.

In the human eye, the iris controls the diameter of the pupil and subsequently the amount of light that reaches the retina. The purpose of an iris, or aperture stop, in a camera is exactly the same; it controls the amount of light that reaches a camera's sensors, which affects the overall focus of the image.

Traditionally, cameras have contained a set of overlapping blades that are mechanically moved to change the size of the hole -- or aperture -- through which light enters. However, with the rising popularity of small, compact and lightweight consumer devices that are integrated with cameras, it has been almost impossible to miniaturise these mechanical systems.

The researchers, from the University of Kaiserslautern, have proposed an alternative method using an electrochromic material. This material, which is often referred to as "smart glass," transforms from a transparent material into an opaque material when a small electrical voltage is applied to it.

In their study, the researchers fabricated a micro-iris using two glass substrates sandwiched together, and with each one carrying a thin film of electrochromic material, called PEDOT, on an underlying transparent electrode.

The micro-iris was 55 µm thick and could be switched into an opaque state using a current of 20 µA with a voltage of 1.5 V.

The micro-iris exhibited a memory effect and did not require a continuous current to maintain the opaque state, so its power consumption remained very small.

In addition to testing the intensity of light that passed through the micro-iris, as well as the amount of time it took to switch between different states, the researchers also examined the depth of focus that the micro-iris was able to impart in comparison to a traditional blade-based iris.

Lead author of the research Tobias Deutschmann said: "There is currently no technological solution available that meets all the demands of integrated iris apertures in smartphones.

"Many of the proposed devices require the motion of a strong absorbing material to block the path of light. Electrochromic materials, as used in this study, remain stationary whilst they change their absorption, so there is no need for any actuation. This allows for much smaller casings to fit around the devices and thus enables the integration into tiny camera systems”.

"We will now further investigate the potential of optimized electrochromic materials, with a particular focus on improving the optical contrast and, in particular, the control of the depth of focus -- this is the decisive hardware parameter which determines the success of next-generation models in the smart phone business."