An Ultra-thin Light-field Camera
The Korea Advanced Institute of Science and Technology announced on Feb. 4 that its research team led by bio and brain engineering professor Jeong Ki-hun has developed an ultra-thin light-field camera capable of providing a high-resolution image by using a nano-metallic light absorbing layer.
A light-field camera can be defined as a combination between a microlens and an objective lens. It is characterized by obtaining the direction as well as the space of light. It is also called a 4D camera because it contains 2D light angle information in 2D pixel information.
In the camera developed by the team, the light absorbing layer of nano thickness is inserted between microlens arrays to result in contrast and resolution enhancement. The layer is a metal-dielectric-metal thin film with a thickness of 200 nm and the team reduced the gap between the objective lens and the microlens to make the camera extremely thin.
In the light absorption structure, the chromium metal has a low level of dispersibility along with excellent optical characteristics, the glass layer has a high level of transmittance, and the two are laminated to be capable of completely absorbing visible light, removing optical crosstalk and making it easier to obtain a high-contrast and high-resolution 3D image.
The team placed the microlens in the opposite direction to the image sensor to minimize the thickness of the camera and reduced the distance between the objective lens and the microlens to as small as 2.1 mm. The thickness of the camera as a whole is 5.1 mm, thinner than any other existing light-field cameras. The technique is expected to be applicable to medical imaging, biometrics, mobile cameras, VR and AR cameras, and so on.