'Smart glass' micro-iris for smartphone cameras

June 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: QUT researcher eyes off a biometric future

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

Related Stories

QUT researcher eyes off a biometric future

December 4, 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 ...

Micro cameras flex their way into the future of imaging

September 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.

NASA's IRIS spots its largest solar flare

February 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 that stream out ...

Recommended for you

Quantum matter stuck in unrest

July 31, 2015

Using ultracold atoms trapped in light crystals, scientists from the MPQ, LMU, and the Weizmann Institute observe a novel state of matter that never thermalizes.

New blow for 'supersymmetry' physics theory

July 27, 2015

In a new blow for the futuristic "supersymmetry" theory of the universe's basic anatomy, experts reported fresh evidence Monday of subatomic activity consistent with the mainstream Standard Model of particle physics.

Rogue wave theory to save ships

July 29, 2015

Physicists have found an explanation for rogue waves in the ocean and hope their theory will lead to devices to warn ships and save lives.

Researchers build bacteria's photosynthetic engine

July 29, 2015

Nearly all life on Earth depends on photosynthesis, the conversion of light energy into chemical energy. Oxygen-producing plants and cyanobacteria perfected this process 2.7 billion years ago. But the first photosynthetic ...

0 comments

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.