The camera of the first iPhone in 2007 was only 2 megapixels. And it only had a rear camera; there was not even a selfie shooter facing forward. Today, you’ll find several cameras on the front and back of phones – some with sensors up to 108 megapixels, like the largest camera on the Samsung Galaxy S21 Ultra.
But while the sensor size and megapixel count of smartphone cameras have increased considerably over the past decade – not to mention improvements in computer photography software – the lenses that help you capture photos remain essentially unchanged.
A new company called Metalenz, which emerges from the stealth mode today, is trying to dismantle smartphone cameras with a single flat lens system that uses a technology called optical meta-surface. A camera built around this new lens technology can produce an image of it, if not better, quality than traditional lenses, collect more light for brighter pictures and may even allow new ways of detection on phones, taking up less space.
A flat lens
How it works? Well, first it is important to understand how the phone’s camera lenses work today. The imaging system on the back of your smartphone can have multiple cameras – the latest iPhone 12 Pro has three cameras on the back – but each camera has multiple 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 multi-lens design like that of the iPhone is superior to a single lens configuration; as the light passes through each successive lens, the image gains clarity and clarity.
Julian Knight
“Optics generally on smartphones today consist of four to seven lens elements,” says Oliver Schindelbeck, innovation manager at optics manufacturer Zeiss, which is known for its high-quality lenses. “If you have a single lens element, just for physics, you will have aberrations like distortion or dispersion in the image.”
More lenses allow manufacturers to compensate for irregularities such as chromatic aberration (when colors appear at the edges of an image) and lens distortion (when straight lines appear curved in a photo). However, stacking multiple lens elements on top of each other requires more vertical space within the camera module. It is one of the many reasons why the “impact” of the camera on smartphones has grown more and more over the years.
“The more lens elements you want to include in a camera, the more space it needs,” says Schindelbeck. Other reasons for the size of the relief include larger image sensors and more cameras with zoom lenses, which need extra space.
Phone makers like Apple have increased the number of lens elements over time, and while some, like Samsung, are now doubling the optics to create “periscope” lenses for greater zoom capabilities, companies have generally kept to themselves the stacked lens element proven system.
“Optics just got more sophisticated, you added more lens elements, you created strong aspherical elements to achieve the necessary space reduction, but there has been no revolution in the last 10 years in this field,” says Schindelbeck.
Introducing Metalenz
This is where Metalenz comes in. Instead of using plastic and glass lens elements stacked on top of an image sensor, Metalenz’s design uses a single lens built on a glass wafer size from 1×1 to 3×3 mm. Look closely at the microscope and you will see nanostructures measuring 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 was working on his doctorate. at Harvard University with the acclaimed physicist and Metalenz co-founder Federico Capasso. The company was split off from the research group in 2017.
The light passes through these standardized nanostructures, which look like millions of circles with different diameters at the microscopic level. “Just as a curved lens speeds up and slows down the light to bend it, each one allows us to do the same thing, so we can bend and shape the light just by changing the diameters of these circles,” says Devlin.
Julian Knight
The resulting image quality is as clear as you would get from a multi-level system, and nanostructures do the job of reducing or eliminating many of the degrading image aberrations common to traditional cameras. And the design doesn’t just save space. Devlin says that a Metalenz camera can provide more light back to the image sensor, allowing for brighter and sharper images than you would get with traditional lens elements.
Another benefit? The company has formed partnerships with two semiconductor leaders (which currently can produce one million Metalenz “chips” per day), which means that the optics are made in the same foundries that manufacture consumer and industrial devices – an important step in simplifying the supply chain.
New ways of detection
Metalenz will enter mass production at the end of the year. Your first application will be to serve as a 3D sensor lens system on a smartphone. (The company did not provide the phone manufacturer’s name.)
Devlin says current 3D sensors, like Apple’s TrueDepth camera for facial identification, actively illuminate a scene with lasers to scan faces, but that can drain the phone’s battery. Since Metalenz can bring more light to the image sensor, he says it can help conserve energy.
Other good news? If it’s a 3D sensor on the front of a phone for facial authentication, Devlin says the Metalenz system can eliminate the need for a bulky camera notch projecting on the screen, like that of today’s iPhones. The amount of space saved by the abandonment of traditional lens elements will allow more phone manufacturers to place sensors and cameras under a device’s glass screen, something we will see more of this year.
Devlin says that Metalenz’s applications go beyond smartphones. The technology can be used in everything from health instruments to virtual and augmented reality cameras to car cameras.
Take spectroscopy as an example. A spectrometer is used to accurately detect different wavelengths of light and is commonly used in medical trials to identify specific molecules in the blood. As the meta-surfaces allow you to collect “an optical table on a single surface”, Devlin says that you can place the right sensors on a smartphone with Metalenz to do the same type of work.
“You can actually look at the chemical signature of the fruit with a spectrometer and tell if it is ripe,” says Devlin. “In fact, it is no longer just an image, you are really accessing all kinds of different forms of meaning, and seeing and interacting with the world, getting a new set of information on your cell phone.”
This story originally appeared on wired.com.