Creating a “Super Pixel”: Samsung Claims Industry’s Smallest Mobile Image Sensor
Last week, Samsung released their newest mobile image sensor which they claim is the industry’s smallest pixel size. What are the implications of this shrinking?
The world of smartphones is constantly in flux with newer and newer technology, with one of the largest focuses from generation to generation on improving camera quality. As a result, a central selling point of new smartphones is often a new and improved camera, which means that there has been heavy demand on the hardware side to improve this technology continually.
Smartphones have greatly impacted the world camera market. Image [modified] used courtesy of Statista and CIPA
To this end, Samsung has been one of the major players in mobile imaging. Especially considering last week, Samsung made headlines announcing its newest mobile imaging sensor, which claims to have the industry's smallest pixel size.
This article will discuss the new product, why Samsung wants to go smaller, and what the implications of this shrinking are.
The Samsung ISOCELL JN1
According to Samsung, its newest mobile image sensor, the ISOCELL JN1, is a novel advancement in the industry, mainly because of its size.
The ISOCELL JN1. Image used courtesy of Samsung
Specifically, the JN1 comes in at a tiny 0.64µm pixel size, meaning that with its 1/2.76 inch optical format, the sensor can achieve an effective resolution of 50 MP. The sensor can achieve normal frame rates up to 10 fps and a video frame rate of 30 fps at 12.5 MP resolution at this resolution.
From a hardware perspective, this sensor also features a 10-bit accurate ADC and a sensor analog gain of 16x.
According to Samsung, achieving such a tiny pixel size has allowed ISOCELL JN1 to be its most versatile image sensor yet. Through ecosystem partners, Samsung has shown that the new sensor can be used in various imaging applications, including front-facing, ultra-wide, telephoto, and standard wide camera configurations.
On top of this, Samsung claims that, since the sensor is so small, it could reduce camera module height by 10%, which helps reduce the camera's bulge in a smartphone, allowing for a slimmer and sleeker design.
In theory, this smaller sensor sounds optimal; however, there are always drawbacks and challenges. What exactly are the challenges of shrinking mobile image sensors to this size?
Challenges with Going Smaller
While decreasing pixel size has allowed for a more versatile camera, many familiar with the field know that decreasing image sensor pixel size often decreases performance.
The jargon can get confusing across the industry, but concerning image sensors, a pixel is a photoreceptor area that collects light (as focused by the camera) lens. The photoreceptor converts the light into an electric signal which the system can then interpret as an image.
Naturally, a larger photoreceptor can capture more light and thus better interpret the received image. On the flip side of this, making image sensor pixels smaller means less light can be captured by each photoreceptor, significantly decreasing the signal-to-noise ratio, making for lower resolution images.
Despite this challenge, there is a possible solution in pixel binning.
One way that many image sensors, including the new ISOCELL JN1, address this size/resolution tradeoff is through pixel binning.
An example of pixel binning which increases the signal-to-noise ratio. Image used courtesy of Abramowitz et al
To oversimplify, pixel binning is the process of combining multiple adjacent CMOS image sensor pixels (photoreceptors) into one "super-pixel."
This super-pixel effectively increases the pixel's area, allowing the camera to achieve a higher signal-to-noise ratio.
This technique becomes particularly useful in low-light environments, where the signal-to-noise ratio is inherently decreased. As for the ISOCELL JN1, it uses four-to-one pixel binning, where four adjacent 0.64µm pixels combine to form a 1.28µm pixel––quadrupling light sensitivity.
Samsung's ISOCELL JN1 seems to have the potential to be an advantageous image sensor in a wide variety of applications, yet it will depend on how its performance plays out. However, with each new generation of smartphones demanding better and better cameras, it's likely to see the ISOCELL JN1 on the market soon.
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