Ultra-compact High-resolution Image Sensor
Samsung Electronics unveiled two ultra-compact high-resolution image sensors using advanced technologies such as dual pixels and tetracells on October 11. They are expected to be selected by various manufacturers as well as be loaded into the next Galaxy smartphone series.
Isocell is Samsung's image sensor brand. An image sensor is a semiconductor that stores and transmits image signals and allows the user to view pictures with display devices by converting light from the camera lens into electrical digital signals. Isocell is classified into four sub-brands such as Fast, Slim, Bright and Dual.
The two new image sensor products introduced by Samsung Electronics are characterized by high image quality and the use of small areas at the same time. Higher smartphone cameras’ picture quality becomes, the wider areas image sensors need. But space limits of image sensors are getting worse as display areas are widened by bezelless designs.
Samsung Electronics explained that its 12-megapixel Isocell Fast 2L9 and 2,400-megapixel Isocell Slim 2X7 image sensor met such needs of the market.
The Isocell Fast 2L9 employs dual pixel technology that provides a fast and accurate auto focus. A dual pixel can focus by integrating two photodiodes in one pixel and detecting a phase difference by comparing two photodiodes contained in one pixel and adjusting the distance so that the distance between the two photodiodes match. Samsung Electronics secured its size competitiveness by pruning the pixel size from 1.4㎛ to 1.28㎛ using fine processing technology.
By using the phase difference between two photodiodes integrated in a dual pixel, the sensor can distinguish a subject and its background and therefore, can implement an out-focus function with one image sensor.
The Isocell Slim 2X7 uses tetracell technology, which automatically adjusts the number of pixels according to shooting environments, making it possible to shoot images with the brightness of 600 megapixels in dark places and 2,400 megapixels in bright places.
A tetracell image sensor can apply one color filter to four pixels to achieve brighter images in the dark. This is Samsung’s sensor technology that applies a relocation algorithm to provide more detailed images in bright places. This ultra-small pixel image sensor breaks down the barrier of a 1.0-μm pixel and reduces pixels down to 0.9 μm.
It has been difficult for ultra-small image sensors with reduced pixel sizes to reproduce accurate colors due to interferences between adjacent pixels, but the Isocell Slim 2X7 adopts the DTI method that forms a physical wall between pixels. By blocking inter-pixel interferences and broadening lighted areas, the Isocell Slim 2X7 improves color reproducibility, while minimizing noises that affects image quality through chip design technology.