Sony is Working on a Sensor with an Integrated Polarizing Filter
A polarizing filter is placed in front of the camera lens in photography in order to darken skies, manage reflections, or suppress glare from the surface of lakes or the sea. Basically polarizing filters used as a tool to reduce glare, minimize reflections. In addition it also improve the color of the sky in photographs by absorbing certain wavelengths of light before they hit the film inside the camera.
There have been several attempts to add polarizers directly inside the camera to reduce the need for fragile external components. But this would make a complicated design product and have limited capabilities.
Meanwhile a leading camera company Sony announced that they are working on a backside-illuminated CMOS sensor which is integrated with polarizing filter. Normally in every prototype polarizing filter is placed in front of the lens. But new Sony’s prototype sensor uses a metal grid atop the sensor’s photo-diodes that acts as a polarizer. This helps to reduce unwanted glare and reflection in image.
Well, they achieved this by angling the metal grid into 4 distinct polarization directions, those are 0, 45, 90 and 135 degrees. By this setup each polarizers used selectively and they can block out only certain light.
In addition sensor is also capable of capture photos with minimal “ghosting”. (This phenomenon occurs when the polarizer acts as a mirror and reflects its own image onto the sensor). To avoid this, company used an anti-reflection layer above the gridded polarizers.
So the bottom line is that, this new design company is now able to construct a smaller and affordable polarization sensors. We will soon see this implementation in upcoming Sony camera.