Cell phones, cars and many other devices have separate cameras and sensors
for day and night vision, but that need could go away thanks to University
of Dayton researchers who developed a single device that can switch between
day and night vision applications.
The journal Optics Express published the researchers' tunable filter work
last month.
UD electro-optics graduate student Remona Heenkenda designed and fabricated
the optical filter under the guidance of UD electro-optics professor Andrew
Sarangan and computer engineering professor Keigo Hirakawa.
Sarangan and Hirakawa said it ultimately would be up to manufacturers to
implement these sensors and cameras into their devices, but they see a
valuable practical application in reducing the number of cameras and sensors
in smartphones and cars, which could reduce cost and increase night safety.
In the optical filter Heenkenda developed, a new material known as phase
change material switches the camera between day and night operation. This
optical filter can be switched on and off using very small heat pulses,
according to Sarangan. The same type of materials also are used to store
data in some computer chips, Sarangan added.
"At night, we want the camera to see better by allowing near infrared light.
During the day, near infrared makes colors funky, so we want to block it
from the camera," Hirakawa said. "So we need to filter out near infrared
only during the day. Our switchable filter uses phase changes to block or
pass near infrared light to the camera." Optimization, he added, would be
automated switching based on the filter recognizing night by clock or the
amount of light.
"Cars are going to be sensors on wheels. It's headed that way," Hirakawa
said. "If you can recycle technology to do two things, and you can save a
nickel or dime per 100 million parts, you can save $10 million. If you can
cut costs and redundancies in your camera or your devices, then it can
potentially be very, very helpful. In automotive, this will be something in
all cars, not just luxury cars, because the savings makes it accessible for
everyone."
As a doctoral student working with Sarangan, Heenkenda also presented at the
Institute of Electrical and Electronics Engineers Photonics conference in
2021. She said she is thankful for the opportunities she gets as a student
at UD.
"There are only a handful of electro-optics and photonics graduate programs
in the country and University of Dayton is one of them with access to
cutting-edge research facilities such as nanofabrication laboratories,"
Heenkenda said. "We are privileged to work with distinguished professors
doing research with industry, thereby consistently staying up-to-date with
the latest research trends. These collaborations open many opportunities for
students to gain invaluable experience preparing them for the future."
Reference:
Remona Heenkenda et al, Tunable optical filter using phase change materials
for smart IR night vision applications, Optics Express (2021).
DOI: 10.1364/OE.440299