The camera on the first iPhone in 2007 was only 2 megapixels. And it only had a rear camera; there wasn’t even a selfie shooter up front. Today, you can find multiple cameras on the front and back of phones – some with sensors up to 108 megapixels, such as the largest camera on Samsung’s Galaxy S21 Ultra.
But while the sensor size and number of megapixels of smartphone cameras have increased significantly over the past decade – not to mention improvements in computer photography software – the lenses that help take photos remain fundamentally unchanged.
A new company called Metalenz, coming out of secret mode today, wants to disrupt smartphone cameras with a single flat lens system that uses a technology called optical metasurface. A camera built around this new lens technology can deliver an image of the same if not better quality than traditional lenses, collecting more light for brighter photos and even enabling new forms of sensing in phones, while taking up less space take.
A flat lens
How does it work? Well, first of all, it is important to understand how telephone lenses work today. The imaging system on the back of your smartphone may have different 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 above iPhone 12 Pro uses seven lens elements. A design with many lenses like the iPhone is better than a single lens setup; as light passes through each successive lens, the image gains sharpness and brightness.
Julian Knight
“Optics currently mostly consist of between four and seven lens elements in smartphones,” says Oliver Schindelbeck, innovation manager at optics manufacturer Zeiss, which is known for its high-quality lenses. “If you have a single lens element, you will only have abnormalities such as distortion or scattering in the image through physics.”
More lenses allow manufacturers to compensate for irregularities such as chromatic aberration (when colors appear on the edge of an image) and lens distortion (when straight lines appear curved on a photo). However, stacking more lens elements on top of each other requires more vertical space within the camera module. This is one of the many reasons why the camera on smartphones has “gotten 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 are larger image sensors and more cameras with zoom lenses that require extra space.
Phone manufacturers like Apple have increased the number of lens elements over time, and although some, such as Samsung, are now folding optics to create ‘periscope’ lenses for greater zoom features, companies have generally stuck to the proven stacked lens element. system.
“The optics have become more sophisticated, you have added more lens elements, you have created strong aspherical elements to achieve the necessary space reduction, but there has been no revolution in the last ten years in this area,” says Schindelbeck.
Introduction of Metalenz
This is where Metalenz comes in. Instead of using plastic and glass lens elements over an image sensor, Metalenz 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 are a thousandth the width of a human hair. These nanostructures bend light rays in a way that corrects many of the shortcomings of single-lens camera systems.
The core technology was formed through a decade of research when co-founder and CEO, Robert Devlin, presented his Ph.D. at Harvard University with renowned physicist and co-founder of Metalenz, Federico Capasso. The company was spun out of the research group in 2017.
Light passes through these patterned nanostructures, resembling millions of circles of different diameters at the microscopic level. “In the way that a curved lens accelerates and decelerates the light to bend it, each of them can do the same thing, so we can bend and shape the light by just changing the diameters of these circles,” says Devlin. .
Julian Knight
The resulting image quality is just as sharp as you would get from a multilens system, and the nanostructures do the job of reducing or eliminating many of the image-degrading aberrations that traditional cameras use. And the design not only saves space. Devlin says a Metalenz camera can deliver more light to the image sensor, enabling brighter and sharper images than traditional lens elements get.
Another benefit? The company has formed partnerships with two semiconductor conductors (which can currently supply one million Metalenz ‘chips’ per day), which means that the optics are manufactured in the same foundries that manufacture consumer and industrial devices – an important step in the supply chain simplify.
New forms of intuition
Metalenz will start mass production by the end of the year. Its first application is to serve as the lens system of a 3D sensor in a smartphone. (The company did not give the name of the telephone manufacturer.)
Devlin says current 3D sensors, like Apple’s TrueDepth camera for Face ID, actively illuminate a scene with lasers to scan faces, but it could be a drain on a phone’s battery life. Since Metalenz can bring more light into the image sensor, he claims it can help save power.
Other good news? If it’s a 3D sensor on the front of a phone for face verification, Devlin says the Metalenz system can eliminate the need for a bulky camera notch on the screen, like those in current iPhones. The amount of space saved by abandoning traditional lens elements will enable more phone makers to place sensors and cameras under the glass window of a device, something we will see more of this year.
Devlin says the applications for Metalenz extend beyond smartphones. The technology can be used in everything from healthcare instruments to augmented and virtual reality cameras, to the cameras in cars.
Take spectroscopy as an example. A spectrometer is used to fine-tune different wavelengths of light, and is commonly used in medical tests to identify specific molecules in the blood. Since with met-surfaces you can ‘collapse a tabletop optics into a single surface’, Devlin claims that with Metalenz you can turn the right sensors in a smartphone to do the same kind of work.
“You can actually look at the chemical signature of fruit with a spectrometer and see if it’s ripe,” says Devlin. “It’s actually no longer just an image; you get access to all sorts of different forms of meaning and sight and interaction with the world, and get a whole new set of information in the phone.”
This story originally appeared on wired.com.