This is the black technology, let you know about Samsung ISOCELL sensor technology

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At the 2017 Mobile World Congress Shanghai MWCS exhibition, Samsung's ISOCELL image sensor department announced four new technology sub-brands, including ISOCELL Bright, ISOCELL Fast, ISOCELL Slim and ISOCELL Dual. Each technology sub-brand targets a specific market, and ISOCELL Dual undoubtedly hints at the dual-camera configuration of this year's Galaxy Note 8.

However, how much do you know about Samsung's ISOCELL image sensor? Let's take a look at it through Samsung's introduction.

What is Samsung ISOCELL?

Samsung's own image sensor brand is named ISOCELL, but this is a technical name, because Samsung first released ISOCELL technology in 2013, claiming that this technology has revolutionized the structure of traditional CMOS image sensors, allowing all pixels to gather more light, and is a new technology that breaks through performance bottlenecks.

ISOCELL is mainly derived from "isolate" and "cell". From a technical perspective, it is to form an absolute physical insulator between the pixels in the image sensor to effectively prevent the light signal entering the pixel from leaking out. In addition, because of the existence of the barrier, the crosstalk between the light signals entering the pixel is also greatly reduced, thereby improving the image clarity and color performance, and achieving excellent image quality even with smaller pixels.

Those who are familiar with traditional back-illuminated (BSI) CMOS should know that this technology is to turn the chip around so that light enters the photodiode first, thereby increasing the light sensitivity and significantly improving the shooting effect under low-light conditions. However, after receiving a large amount of light and color, the back-illuminated technology is prone to mixing and affecting each other between two adjacent pixels. The ISOCELL technology overcomes the shortcomings of the back-illuminated technology and solves the problem of light signals affecting each other by forming a physical barrier between pixels.

Samsung's first smartphone to use ISOCELL technology sensors was the Galaxy S5 flagship. At the time, Samsung made a diagram similar to the one above to explain ISOCELL technology. It is easy to understand from the diagram. The back-illuminated CMOS on the left, the light signals received through the lens are prone to cascade and cause mutual interference, while the image sensor on the right using ISOCELL technology has a physical barrier set up, so the light signal will not run into other pixel blocks.

Samsung said that ISOCELL technology reduces interference by more than 30% compared to traditional back-illuminated technology, improves color reproduction, and also increases the light-receiving area by 30%, allowing for colorful photos to be taken even in dark environments with insufficient light.

What are the characteristics of ISOCELL: bright, fast, thin and dual?

-ISOCELL Dual

With the development of smartphone cameras, especially in terms of technology and pixels, dual-core has become more and more popular under innovative technology, and a large number of manufacturers have begun to use two cameras to form a dual-camera system. ISOCELL Dual uses the currently very popular combination of color lens and black and white lens, in which the RGB color sensor is responsible for basic functions, and the BW black and white sensor is mainly used to collect light.

Normally, traditional single-sensor cameras are prone to high-noise photos in low-light environments. However, according to Samsung, ISOCELL Dual technology can first help "take bright and colorful photos in low-light environments" because black and white sensors can better perceive light and dark details, and combined with pictures taken with color sensors, photos with more colors can be obtained, making the pictures more vivid.

The ISOCELL Dual technology demonstrated by Samsung uses two 13-megapixel sensors, both of which support Samsung autofocus technology. At the same time, the pixel size is 1.12 µm, which is much smaller than the 1.4 µm on the Galaxy S8. After all, dual-camera compromises are necessary. At the same time, it is equipped with an f/2.0 aperture lens, and the amount of light entering is also less than the S8 flagship. Therefore, many people wonder if the Note 8 has such a configuration, it can only improve night shooting. However, Samsung said that this is not a solid-state dual-camera combination. In fact, its own technology can mix sensors with various combinations, and it is not necessarily a display configuration.

Because there are many combinations, Samsung said that ISOCELL Dual technology can also provide "optical zoom" function. By matching a 1 to 2 times wide-angle lens and a telephoto lens, and then synthesizing the two photos through a special algorithm, you can get the effect of optical zoom. Another feature provided by Dual technology is the "selective focus" function, which uses a color sensor and a sensor that adjusts the depth of field to obtain photos with depth of field information. This is what we often say, take a photo first, and then choose the object we want to focus on after taking the photo.

-ISOCELL Bright

The ISOCELL Bright sensor technology specifically refers to the provision of bright and clear images with high color fidelity and ultra-low noise in low-light or dark environments with extremely low light. However, Samsung did not reveal too many details about the Bright sensor design, including specific specifications.

Normally, Samsung should use a slightly larger sensor design in Bright to ensure that more light can be captured. A single pixel may be 1.4 µm in size, which is basically the most suitable pixel size for smartphones, creating advantages from the basic specifications.

However, these are just one of the explanations. Looking back at Samsung's past explanations, it is not difficult to find that Samsung has actually mentioned in the introduction of Bright that they have used a technology called Tetracell, which uses 4 adjacent pixels to merge into 1 large pixel to generate 1 RGB color information. ISOCELL sensors can collect more and more accurate color information, enhance FWC (Full well capacity), thereby improving sensitivity and achieving noise reduction.

Samsung said that ISOCELL Bright technology can take brighter photos in low-light environments, and the improved FWC is up to 40% higher than that of image sensors composed of large pixels. At the same time, Tetracell technology can increase light sensitivity by 20%, ensuring that photos in low light are bright and clear.

-ISOCELL Fast

Samsung will definitely use PDAF phase detection focusing technology in its Fast Sensor technology, which is a method of focusing by calculating and detecting the phase difference of the subject being photographed, and will also add its proud Dual Pixel technology. Traditional PDAF focusing is equipped with about 5% of pixels for measuring phase difference, but Dual Pixel is that all pixels support phase difference measurement, providing faster focusing speed.

As for the technical principle, Samsung explained, "Generally speaking, there is an image diode in the pixel for gathering light, but in the Dual Pixel technology center, each pixel has two image diodes, and the phase difference is determined by comparing the light signals received by each of the two diodes to complete the focusing. Therefore, all pixels can be used for focusing and can also receive light source signals that form pictures. "

In short, ISOCELL Fast technology uses this Dual Pixel technology to provide faster and more accurate autofocus, allowing each pixel to be used to generate an image, and making smartphone photography more consistent with the fast-moving state of the subject, giving users a better shooting experience.

Samsung even proudly stated that its Dual Pixel technology is not only 4 times faster than traditional PDAF autofocus, but also supports autofocus even in a dark environment of only 1lux.

-ISOCELL Slim

Samsung knows that consumers don't like phones that look like cameras, and protruding cameras are not popular. Therefore, Samsung launched Slim technology to ensure that the camera has powerful photo-taking functions while maintaining a slim body. How did Samsung balance the slim body and high-pixel and large-volume sensor?

In order to achieve high pixels in a small-sized image sensor, the most direct approach given by Samsung is to reduce the size of each pixel, so as to ensure that the camera module is still powerful. In fact, it is still a familiar formula of ISOCELL technology. For example, in 2015, Samsung successfully developed a 16-megapixel image sensor composed of 1.0 µm pixels. Samsung reduced the size of the pixel to 1.0 µm, which is one millionth of a meter, so that 16 million 1/3.1-inch pixels can be stuffed into the sensor.

How thin is it? Samsung said that the camera module thickness of the traditional 1.12µm 16-megapixel sensor is 6mm, but with the same pixel sensor, Samsung can design a camera module with a thickness of less than 5mm, so the thickness of the smartphone body can also be designed to be thinner.

Many people may still not understand why a smaller single pixel size is needed. After all, the smaller the pixel, the less light it can absorb, which leads to lower photo quality, and interference is likely to occur between the light signals entering the RGB pixels. But as mentioned at the beginning, Samsung's own ISOCELL technology is able to set up an independent physical barrier between each pixel, isolating the pixels from each other to minimize interference and reduce light signal loss, so that high-quality photos can be taken with a reduced pixel size.

Summary: Brand remodeling is only for greater success

ISOCELL technology is not a new technology launched by Samsung. Now Samsung is just rebranding its own technology to ensure that each advantageous technology has its own brand name. This is not a bad thing, because a separate brand name can allow consumers or Samsung's sensor customers to deepen their understanding of ISOCELL technology, including the brand name, performance and characteristics of the corresponding technology, so as to meet their own needs.

You know, Sony's main Exmor RS/R sensor products are deeply rooted in the hearts of the people, and most of the users know the specific models, but Samsung ISOCELL is not the case. Therefore, Samsung's brand reshaping this time will be of great help to its sensor business to a certain extent.

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