'Smart glass' micro-iris for smartphone cameras

Jun 18, 2014

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 , 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, June 19, in the 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 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 apertures in smartphones.

"Many of the proposed devices require the motion of a strong absorbing material to block the path of light. Electrochromic , 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."

Explore further: A first for NASA's IRIS: Observing a gigantic eruption of solar material

More information: 'Integrated electrochromic iris device for low power and space-limited applications' DOI: 10.1088/2040-8978/16/7/075301. http://iopscience.iop.org/2040-8986/16/7/075301/article

add to favorites email to friend print save as pdf

Related Stories

QUT researcher eyes off a biometric future

Dec 04, 2007

It is not science fiction to think that our eyes could very soon be the key to unlocking our homes, accessing our bank accounts and logging on to our computers, according to Queensland University of Technology researcher ...

NASA's IRIS spots its largest solar flare

Feb 21, 2014

(Phys.org) —On Jan. 28, 2014, NASA's Interface Region Imaging Spectrograph, or IRIS, witnessed its strongest solar flare since it launched in the summer of 2013. Solar flares are bursts of x-rays and light ...

Micro cameras flex their way into the future of imaging

Sep 20, 2013

Imagine sticking a thin sheet of microscopic cameras to the surface of a car to provide a rear-view image, or wrapping that sheet around a pole to provide 360-degree surveillance of an intersection under construction.

Recommended for you

NIST 'combs' the atmosphere to measure greenhouse gases

Oct 29, 2014

By remotely "combing" the atmosphere with a custom laser-based instrument, researchers from the National Institute of Standards and Technology (NIST), in collaboration with researchers from the National Oceanic ...

Supersonic laser-propelled rockets

Oct 29, 2014

Scientists and science fiction writers alike have dreamt of aircrafts that are propelled by beams of light rather than conventional fuels. Now, a new method for improving the thrust generated by such laser-propulsion ...

Subwavelength optical fibers to diffuse light

Oct 27, 2014

Researchers at the Femto-ST Institute, working in collaboration with colleagues from the Charles Fabry Laboratory (CNRS/Institut d'Optique Graduate School), have just discovered a new type of light diffusion ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.