If you’ve ever tried to take a picture in a dark restaurant, you know that it is difficult to get a clear, quality image. In the future, cameras might not struggle under these conditions thanks to a newly developed method for spherically curving the flat image sensors found in today’s digital cameras.
“Our approach to curving commercially available image sensors could make it possible to have a new class of camera that would be very small, but have image quality that would be comparable to image sensors found in much larger cameras,” said Brian Guenter, leader of the Microsoft Research team. “In addition to improving consumer cameras, curved sensors could be used to create better cameras for surveillance, head-mounted displays and advancements in autonomous vehicle navigation.
Most of today’s cameras use lenses made of multiple optical elements that correct for various optical errors, or aberrations, and that also manipulate the image so that it can be detected by a flat sensor. Using a curved, rather than flat, image sensor means the optical elements have to do less work to correct and flatten the image, making it possible to use fewer optical elements. This not only translates to smaller, faster and less expensive lenses but also makes it easier to improve other properties of the optical components.
“When using curved sensors, it is possible to correct aberrations in a much more efficient way, making it easier to create very wide angle lenses that produce sharp images across the entire field of view or to create fast lenses that produce better images in low light,” said Neel Joshi, a member of the research team. “It is also more straightforward to make cameras that exhibit uniform illumination across the entire image.”
In The Optical Society journal Optics Express, researchers from Microsoft Research and research-and-development laboratory HRL Laboratories LLC, report that their new method can create image sensors with three times more spherical curvature than reported previously. They have been able to incorporate one of the sensors into a prototype camera. Compared to today’s high-end commercial single-lens reflex camera (SLR) cameras, the camera with the new sensor produced higher resolution images across the entire field of view.
“Although the benefits of using curved sensors have been known for some time, our work now makes it practical to create cameras with curved sensors,” said Richard Stoakley, a member of the research team. “Adding spherical curvature to an off the shelf image sensor can be done for a reasonable cost and in a way that shows significant benefits.”
Creating the ideal camera
The new approach for creating curved sensors grew out of a question the researchers asked themselves about seven years ago: “What would an ideal camera be like?” They decided such a camera would take pictures under very low light, be very small, and produce extremely sharp pictures.
“At the time, it wasn’t possible to make a camera like that,” said Guenter. “We thought that if we could improve a camera’s optics by creating a faster lens, we could potentially use a smaller sensor while still gathering enough light to get a good picture. That motivated us to begin investigating curved sensors as a way to potentially achieve breakthrough performance.”
To make curved sensors, the researchers placed individual sensors cut from a thinned CMOS image-sensor wafer into custom-made molds and then used pneumatic pressure to push each sensor down into the mold. Other attempts at curving a sensor have typically involved gluing the edges down and trying to push on the center of the sensor. However, this creates points of high stress that cause the sensor to shatter before it reaches the target level of curvature.
The researchers coaxed significantly more curvature out of the sensors by letting them float freely during the bending process, which allowed stresses to dissipate gradually. They also used a specially shaped mold that very slowly builds stress around the chip’s edges as it is pressed into the mold. Microsoft contracted HRL Laboratories, which has semiconductor fabrication capabilities and equipment, to help solve some of the specific physics challenges involved in bending the sensors.
“This work involved extensive amounts of experimentation,” said Joshi. “Every single surface involved has to be carefully treated to exhibit the exact properties necessary for the sensor to end up with the right amount of stress without breaking.”
Tests showed that curving the sensors did not change any of their electrical or imaging characteristics. When used in a prototype camera with a specially designed f/1.2 lens, a curved sensor exhibited a resolution more than double that of a high-end SLR camera with a similar lens. Toward the edges of the image, the curved sensor was about five times sharper than the SLR camera.
Although most cameras exhibit decreased light detection around the corners of the imaging sensor, the researchers showed that the curved sensors lost almost no light. This was a significant improvement compared to the decrease of around 90 percent measured for the commercial SLR camera.
“We showed that you can take an off-the-shelf sensor, curve it and dramatically improve the performance of the optical system,” said Guenter. “This can be done with relatively low costs and effectively no downside.”
Curved sensors for mobile phones
Although the prototype camera reported in the paper is about the size of a small consumer camera, the researchers say that the lenses could be made small enough for mobile phones and tablets. It should also be possible to build machines that could mass produce these curved sensors, allowing the additional processing to be incorporated into existing sensor manufacturing in a way that would amortize well in volume production.
The researchers are now working to see if further improvements might produce sensors with even more curvature. They also want to experiment with curving sensors that operate in infrared wavelengths, which could be useful for telescopes, 3D spatial mapping, biometric authentication and various scientific applications. Although they caution that it is unlikely that commercial products featuring the curved sensors will be available soon, they are interested in working with other companies to further improve the sensors and to perform the strenuous robustness testing that would be needed to prepare for mass production.
“I think we have opened the door for an entirely new class of lenses,” said Stoakley. “I’m excited to see how our group and others use curved sensors to achieve even more improvements in camera quality through innovative lens design.”
The Latest on: Curved sensors
AOC Announces AGON AG322QC4 32-Inch Curved LCD with FreeSync 2 & DisplayHDR 400
on April 18, 2018 at 7:00 am
The curved 32-inch AGON AG322QC4 monitor has a QHD resolution as well as a 144 Hz refresh rate, which is in line with other gaming monitors these days. The monitor also carries DisplayHDR 400 certification, meaning it falls under the VESA's entry-level HDR ... […]
Benq goes FreeSync 2 with 32-inch EX3203R monitor
on April 18, 2018 at 5:52 am
It appears that the FreeSync 2 monitor market is finally heating up and Benq is among the first to join the new wave with its curved 32-inch EX3203R monitor which uses a 2560x1440 resolution VA panel with 144Hz refresh rate. The Benq EX3203R monitor is ... […]
Benq EX3203R 144Hz QHD gaming monitor launched
on April 18, 2018 at 4:01 am
... boxes for PC enthusiasts and gamers out there - or at least it plays a good game of monitor tech buzzword bingo. The new Benq EX3203R is, in brief, a 32-inch curved gaming monitor with a 144Hz refresh QHD panel, offering HDR visuals, FreeSync 2 ... […]
Dell Ultrathin S2419HM Monitor Review
on April 17, 2018 at 3:49 pm
The gaming-oriented Asus VG245H (252.6 nits) falls behind on brightness, while the wide-screen, curved Dell P3418HW monitor managed only 263.8 nits. The monitor boasts a peak brightness of 600 nits when displaying HDR content. Compared to other monitors we ... […]
AOC 40-inch 4K Monitor (C4008VU8) Review
on April 17, 2018 at 10:41 am
If you want something a little more reasonable, the wide-screened Dell P3418HW is good for office workers who can make do with 1080p resolution. And Acer Predator X34 gives you a great gaming monitor with 4K and a curved screen that won't bowl you over. […]
Elephone U Pro Review – Curved Edges are Not Enough
on April 17, 2018 at 6:24 am
The curved edges make it feel like a pebble designed to fit perfectly ... Join GizChina on Telegram The fingerprint sensor is unusually slow which is most likely a software issue. It takes over 1 second to unlock the phone when you position your finger ... […]
Amazon customers can get a great deal on a curved monitor from Samsung today
on April 11, 2018 at 9:51 am
The Insider Picks team writes about stuff we think you'll like. Business Insider has affiliate partnerships, so we get a share of the revenue from your purchase. I've been using one at home and work for years, and whether you opt to use the external ... […]
Immerse yourself in this massive 32-inch, curved Samsung monitor for just $190 today
on April 11, 2018 at 7:12 am
A gigantic, curved display can make your PC experience feel wonderfully immersive, regardless of whether you’re gaming or slinging spreadsheets around. Impressive monitors like that don’t come cheap, though—at least usually. Amazon’s featured deal ... […]
Samsung 49 inch QLED business monitor review: Multi-tasking single monitor setup
on April 9, 2018 at 7:21 am
However, if your single monitor is a Samsung C49HG90 49 inch curved widescreen, then a single monitor may just be perfect. I started using my laptop with an external display at the office a few years ago and then setup my home office with a laptop ... […]
An ultrawide monitor made me fitter, happier, and more productive
on April 8, 2018 at 6:39 pm
I walked into a friend's office and saw his Dell UltraSharp 38 curved monitor and knew I had to have it. With a 21:9 aspect ratio, the monitor looks comically misshapen when you take it out of the box, but when you're sitting in front of it, the subtle ... […]
via Google News and Bing News