The camera on the first iPhone way back in 2007 was only 2 megapixels. And it only had a rear camera; it was not even a front-facing selfie shooter. Today, you can find several cameras on the front and back of phones – some of them with sensors as large as 1
But while the sensor size and number of megapixels on smartphone cameras have increased significantly over the past decade – not to mention improvements in computational photography software – the lenses that help capture images remain fundamentally unchanged.
A new company called Metalenz, emerging from hidden mode today, wants to disrupt smartphone cameras with a simple, flat lens system that uses a technology called optical meta-surfaces. A camera built around this new lens technology can produce an image of the same if not better quality than traditional lenses, collect more light for brighter images, and can even enable new forms of sensing in phones, while taking up less space.
A flat lens
How does it work? First, it is important to understand how telephone lenses work today. The imaging system on the back of your smartphone may have multiple cameras – the latest iPhone 12 Pro has three cameras on the back – but each camera has several lenses or lens elements stacked on top of each other. The main camera sensor on the aforementioned iPhone 12 Pro uses seven lens elements. A design with many lenses like the iPhone is better than a simple lens setup; when light passes through each successive lens, the image gains sharpness and clarity.
“Optics in smartphones today typically consist of between four and seven lens elements,” says Oliver Schindelbeck, head of innovation at optics manufacturer Zeiss, which is known for its high-quality lenses. “If you have a single lens element, you will only have deviations from physics such as distortion or scattering in the image.”
Multiple lenses allow manufacturers to compensate for irregularities such as chromatic aberration (when colors appear at the edge of an image) and lens distortion (when straight lines appear curved in an image). However, stacking several lens elements on top of each other requires more vertical space inside the camera module. This is one of the many reasons why the camera “bumps” on smartphones has become bigger and bigger over the years.
“The more lens elements you want to pack in a camera, the more space it needs,” says Schindelbeck. Other reasons for the size of the bump include larger image sensors and multiple cameras with zoom lenses, which need extra space.
Phone manufacturers like Apple have increased the number of lens elements over time, and while some, like Samsung, are now folding optics to create “periscope” lenses for larger zoom features, companies have generally stuck to the tried and true stacked lens element. system.
“The optics became more sophisticated, you added more lens elements, you created strong aspherical elements to achieve the necessary reduction in space, but there has been no revolution in the last 10 years in this field,” says Schindelbeck.
We present Metalenz
This is where Metalenz comes in. Instead of using plastic and glass lens elements stacked over an image sensor, Metalenz design uses a single lens built on a glass plate that is between 1×1 and 3×3 millimeters in size. Look very closely under a microscope, and you will see nanostructures that measure a thousandth of the width of a human hair. These nanostructures bend light rays in a way that corrects for many of the shortcomings of single-lens systems.
The core technology was formed through a decade of research when co-founder and CEO Robert Devlin worked on his doctorate. at Harvard University with renowned physicist and Metalenz co-founder Federico Capasso. The company was spun out of the research group in 2017.
Light passes through these patterned nanostructures, which look like millions of circles of different diameters at the microscopic level. “Much like the way a curved lens speeds up and lowers light to bend it, each of these enables us to do the same thing, so that we can bend and shape light just by changing the diameters of these circles,” he says. Devlin.
The resulting image quality is as sharp as that of a multilens system, and the nanostructures do the job of reducing or eliminating many of the degrading deviations common to traditional cameras. And the design not only saves space. Devlin says that a Metalenz camera can deliver more light to the image sensor, resulting in brighter and sharper images than what you get with traditional lens elements.
Another benefit? The company has formed a partnership with two semiconductors (which can currently produce one million Metalenz “chips” a day), which means that the optics are made in the same foundries that produce consumer and industrial units – an important step in simplifying the supply chain.
New forms of sensing
Metalenz will go into mass production towards the end of the year. The first application will be to act as the lens system of a 3D sensor in a smartphone. (The company did not state the name of the telephone manufacturer.)
Devlin says that current 3D sensors, such as Apple’s TrueDepth camera for Face ID, actively illuminate a scene with lasers to scan faces, but this can be a drain on battery life. Since Metalenz can provide more light to the image sensor, he claims that it can help save energy.
Other good news? If there’s a 3D sensor on the front of a face recognition phone, Devlin says the Metalenz system can eliminate the need for a bulky camera notch entering the screen, like that of today’s iPhones. The amount of space saved by leaving traditional lens elements will allow more phone manufacturers to put sensors and cameras under a device’s glass display, something we’ll see more of this year.
Devlin says that the applications for Metalenz extend beyond smartphones. The technology can be used in everything from health instruments to magnified and virtual reality cameras, to the cameras in cars.
Take spectroscopy as an example. A spectrometer is used to detect different wavelengths of light, and it is often used in medical analyzes to identify specific molecules in the blood. Because metasurfaces allow you to collapse “a tabletop with optics into a single surface”, Devlin claims that you can throw the right sensors in a smartphone with Metalenz to do the same type of work.
“You can actually look at the chemical signature of fruit with a spectrometer and tell if it’s ripe,” says Devlin. “It’s not really just a picture anymore, you actually get access to all sorts of different kinds of sense, and see and interact with the world and get a whole new set of information for your mobile phone.”
This story originally appeared on wired.com.