The amazing feat of vision first appeared on Earth more than 500 million years ago. Over time, most animals, including humans, developed two eyes along with a supporting function known as binocular disparity – the ability to measure distance using these two eyes.
This same concept has been replicated in smartphone cameras to help them focus on an image through a technology called phase detection auto focus (PDAF).
SK hynix, though, recently unveiled a new technology called the All 4-Coupled (A4C) image sensor that provides a giant leap forward in camera sensor technology, much better than conventional PDAF. In this recent EE Times column [LINK], Tae-hyun (Ted) Kim, head of the CIS ISP at SK hynix, explains how A4C technology works and the benefits it delivers.
Similar to today’s Quad sensors, A4C uses a photodiode to convert light into an electric current and color filters to selectively absorb certain light wavelengths. Unlike Quad sensors, however, the A4C structure has one micro lens on each group of four-color filters of the same color pixels.
Using this unique structure, a subject is determined to be in focus if the different rays of light from the subject converge to one focal point. In other words, the intensity value is the same for the four pixels under one micro lens.
This unique structure and supporting SK hynix technology promises to dramatically improve smartphone cameras with faster and more accurate focus of images. The images captured also have higher-resolution, providing more detail for computer vision applications.
For more on this important technology, click on this link to read the column — SK hynix’s Next-Generation CMOS Image Sensor: All 4-Coupled (A4C) Sensor [LINK]
