In addition to Sony, Samsung, Omnivision (hereinafter referred to as OV), Canon and other manufacturers actually produce CMOS, of course, not limited to the smartphone field. In recent years, mergers and acquisitions among CMOS manufacturers have brought about subtle changes in the market structure.

At the end of October 2015, Toshiba confirmed to sell its image sensor (CMOS) business to Sony, and reorganized its loss making semiconductor business. At the beginning of December of the same year, Sony announced the purchase price of 19 billion yen, including Toshiba semiconductor manufacturing plant and wafer production line, and 1100 employees were joined by Sony. Before that, Sony CMOS had accounted for more than 30% of the global image sensor market share. Japan Softbank acquired ARM this year. I believe many readers know about it, but they did not know that as early as 15 years ago, the Chinese investment consortium (composed of three companies) also achieved success and successfully acquired the American OV. On Semiconductor, another of the top ten manufacturers in CMOS market share, acquired Fairchild.

According to the list of the top ten global CMOS market shares published by foreign media in the early years, in addition to the above manufacturers, there are actually Panasonic, SK Hynix, Gekewei and STMicroelectronics.

Omnivision

The OV sensor was originally used for the position of the iPhone main camera. Since the iPhone 4S was changed to Sony, the OV position was adjusted to the front camera. Subsequently, the mobile phone industry also gradually formed the mode of front OV+rear Sony. Later, with the rise of Samsung and other manufacturers, OV market share gradually declined.

Everyone is familiar with Sony's stack structure, but not many readers know about the PureCel-S technology similar to OV. After years of accumulation, some OV sensors also have similar Sony CMOS technology, phase focusing, hardware HDR, not to mention the skill of stacking pixels. I still remember that before Sony launched the 23 million pixel sensor on the mobile phone, OV already had a 24 million pixel sensor. I believe that everyone will remember the Jinli E8 main camera. Next, we will review some classic OV sensors.

At the beginning of HTC One (M8), the CMOS supplier adopting UltraPixel technology was replaced with OV, and at the same time, the OV's 2 million pixel auxiliary lens was introduced, which was only responsible for recording the depth of field information. In the same year, HTC Butterfly 2 and HTC One M8 Eye replaced the UltraPixel technology CMOS with IMX214, and the OV status was once again shaken by Sony.  

One of the CMOS chips with UltraPixel technology is OV468x, with a unit pixel size of 2 μ m. Of course, the first manufacturer to use this technology was STMicroelectronics. Later, HTC replaced the supplier with OV for various reasons. The UltraPixel at that time was not like the 12 million pixel CMOS chip on the HTC 10 today. The resolution of only 4 million pixels could not withstand amplification. On the other hand, it did not support 4K video recording.

From the above table, we can see that many OV sensors actually support the output of RAW photos. The key is the mobile phone manufacturer's product positioning and the SoC platform computing capability. If only an entry-level mobile phone or only a Snapdragon 200 processor is equipped, it is obviously unnecessary to develop a corresponding interface in the system to process RAW photos.

Finally, let's focus on the Glory 6 Plus, an early dual camera phone, which uses two OV8865 sensors. Although the unit pixel size is only 1.4 μ m. However, Huawei claims that it is technically equivalent to implementing 1.98 μ M unit pixel size. Theoretically, it can receive more light, making the performance more brilliant in weak light. On the other hand, Huawei claims that it can achieve faster HDR synthesis speed through two sensors and ISP. Triangle focusing enables the Glory 6 Plus to achieve 0.1s fast focusing. In addition, EDoF technology is also realized, which can break through the limitation of fixed aperture of smart phone lens, extend the depth of field of the overall picture to infinity, and reduce the phenomenon of virtual local area of the picture caused by large aperture of smart phones. Glory 6 Plus can also achieve a long exposure for one camera, and a short exposure for 1/15s for the other camera. Photos can be synthesized through a combination of long and short exposures. As for analytical power, two cameras can compose a 13 million pixel photo.

Then let's look at the OV sensors of more than 10 million levels. From the above parameters, the author speculates that the second generation of HTC 10 sensors using UltraPixel technology is actually OV12890. Although HTC has not announced the source of the sensor, many parameters are very consistent. Sony also has an IMX378 corresponding to it, and the unit pixel size of both sensors has reached 1.55 μ m. It is among the best in this indicator of smart phones.

Similar to Sony IMX series sensors, OV will also show that the sensor supports 4K video recording, but for some reasons, mobile phone manufacturers limit a model to only support 1080P video recording, such as Moto X, OPPO N3 and Jinli E7.

With the accumulation of CMOS experience, some sensors of OV also began to support phase focusing and hardware HDR technology, such as OV21840 and OV23850. The latter has achieved 24 million pixels resolution earlier than Sony, and 120 million pixels can be achieved on the Jinli E8 through super pixel technology.

Samsung

Before the Samsung Galaxy S5, Samsung sensors basically only appeared in entry-level thousand yuan machines, and there was no ISOCELL technology. Samsung Galaxy S5 has become famous for its ISOCELL pixel structure. The principle is to reduce pixel crosstalk by forming a physical barrier between adjacent pixels, which will be described in detail below. In recent years, Samsung has adopted the principle of mixed supply for the main camera CMOS of its flagship machine. Sony IMX series and Samsung ISOCELL sensors are used for different versions of mobile phones in different regions. After increasing popularity, Samsung sensors with ISOCELL pixel structure are gradually promoted to more domestic manufacturers. Some models of Nubia, 360, Xiaomi, OPPO and other manufacturers also began to try this sensor. DTI image quality enhancement technology on some Sony CMOS devices. Through technical interpretation, we know that its principle is similar to ISOCELL pixel structure.

From the table above, we can see that Samsung, OV and Sony CMOS are not only competing in the field of main cameras, but also in front cameras. On the other hand, in the past two years, many thousand yuan main cameras have adopted Samsung sensors, such as the Red Rice Note 2, which was known as the new national product movement. Of course, not all Samsung sensors use ISOCELL pixel structure, such as S5K3L2.

The classic ISOCELL sensors listed above in recent years are all 10 million level sensors, which are divided into 12 million pixels, 13 million pixels and 16 million pixels.

12 megapixel : In fact, the Samsung Galaxy S7/S7 edge is not the first ISOCELL sensor with 12 million pixels. It has been 12 million pixels since the Samsung Galaxy Alpha. Of course, the specifications of these two sensors are not the same. The ISOCELL sensors on Samsung flagship computers before the Samsung Galaxy S7/S7 edge are basically 16:9 native frame size, and this wide viewing angle design was not abandoned until this year's generation of 12 million pixel sensors. 16: The advantage of 9 native frames is that you can get 16:9 viewfinder when you turn on full pixels. In contrast, if CMOS with 4:3 frame design wants to obtain 16:9 frame view, the obtained photos cannot be turned on to full pixels. For example, 13 million pixel photos can be obtained when 4:3 frame view is taken, and only less than 13 million pixel photos can be obtained when 16:9 frame view is taken. After several years of development, Samsung has not only been able to realize phase focusing technology on its own sensors, but also introduced dual pixel focusing technology of SLR cameras on the latest generation of ISOCELL sensors. 4K video recording and hardware HDR technology are also easy.

13 million pixels : Although many manufacturers have not indicated which ISOCELL sensor is used, the S5K3M2 can basically be locked in terms of specifications and parameters. The model and specification of nubia My Prague is very consistent with that of S5K3M2. It is not ruled out that the same sensor has different names. As for the 1.34 adopted by the two models of Lenovo's ZUK Z2 series μ The m unit pixel size sensor is estimated to be from another model. Similar to Sony and OV sensors, Samsung's ISOCELL sensors sold to other manufacturers will be weakened in function, for example, they do not support 4K video recording and hardware HDR.

16 million pixels : The unit pixel size of S5K3P3 on the full Netcom version of Hongmi Note 3 is only 1 μ m. As the main lightweight model, it does not protrude from the body in appearance. The structure of the remaining two S5K2P8 and S5K2P2 is very similar. The biggest difference is that the latter supports phase focusing technology, and has used many Samsung flagship computers, until the Samsung Galaxy S7/S7 edge began to step down. It is estimated that 360 and Jinli mobile phones also use this sensor, but the hardware HDR function is castrated, and the frame of view is not 16:9 when full pixel is turned on.

Finally, let's talk about which technologies are included in ISOCELL pixel structure. It is roughly divided into F-DTI, VTG, Smart WDR intelligent wide dynamic technology and RWB imaging technology. F-DTI is the basic function of ISOCELL pixel structure, which can reduce the crosstalk between pixels as described above. In contrast, VTG technology is often ignored. In short, it can change the position of the photodiode from lying flat in the pixel unit to standing up. This brings two benefits. First, it can make full use of the incident light to reduce the side effect of the F-DTI structure weakening the light. Second, it can improve the space utilization of the photosensitive elements, so that mobile phone manufacturers can further improve the pixel.

The ISOCELL model on the full Netcom version of Hongmi Note 3 also supports Smart WDR intelligent wide dynamic technology and RWB imaging technology. The former is similar to Sony's SME HDR function, that is, it provides hardware HDR when recording video. The latter mainly functions like the RGBW structure on IMX278. The RGB W structure can change the structure of the color filter on the top of the sensor's internal photosensitive element, add a colorless filter area on the basis of the RGB three primary colors, and capture only the light intensity but not the light color. RWB imaging technology is more extreme, abandoning the traditional filter design, changing the arrangement order of each pixel in the sensor, replacing green pixels with white pixels, so that more light passes through the sensor filter, making the picture brighter.

Toshiba and Panasonic

Before the acquisition of Toshiba's CMOS department by Sony, there were many achievements. In fact, Nokia's two epoch-making CMOS were actually made by Toshiba. The 20 million pixel sensor of HTC One M9 and HTC One M9+comes from Toshiba T4KA7. The overall quality is not too high compared with Sony's models of the same level, but the pixel value is there after all.

Panasonic's CMOS market share is estimated to mainly come from the digital camera field. What we can recall in the smartphone field in recent years is that the CMOS independently developed by Panasonic is estimated to be only the 1-inch big guy on the Panasonic Lumix CM1.

Canon, SK Hynix and STC

Canon is self-sufficient in the field of digital cameras, customizing flagship CMOS for its own products, but it has little success in mobile phone sensors, so most of the CMOS market share benefits from the field of digital cameras. Inter bee 2014 once again demonstrated 120 million pixel top CMOS, which can be used in civil, traditional industry, aerospace and other fields. In 15 years, a 250 million pixel APS-H frame CMOS with a resolution of up to 1958 * 12600 was released, which set the world record for sensors of the same size at that time and can be used in Canon EOS-1D series SLR cameras. The Canon EOS-1D X Mark II launched this year uses the newly developed 2020 megapixel CMOS and dual DIGIC 6+image sensors, and again introduces the Dual Pixel CMOS AF (full pixel dual core CMOS AF) technology.

SK Hynix has been very famous in the semiconductor field, but it has not been a long time to set foot in CMOS, mainly with 8 million pixel sensors or less. According to the parameters of some sensor models launched in the past few years, the hard indicators are not very strong, and the main reason is to seize the market at low prices.

STMicroelectronics customized a unit pixel size of up to 2 for the New HTC One μ Although the m-sensor has only 4 million pixels, it has higher resolution and brightness than those smart phones with more than 8 million pixels at that time when it is combined with the optical anti shake lens group and F2.0 large aperture. However, due to the immature technology at that time, HTC One (M8) changed the supplier to OV in the second year, and introduced the depth of field lens, but removed the optical anti shake lens set. In addition, STC is not very influential in the CMOS world.

summary

Today's Sony sensors have a stronger sense of presence than Sony phones. Although Sony IMX series sensors have shaken the position of CMOS in the main camera position compared with Samsung, OV and other manufacturers, they can still defend the throne on the whole. This year, for example, HTC and Yijia mobile phone flagship have abandoned Toshiba and OV sensors and returned to Dafa. On the other hand, Samsung ISOCELL sensors are gradually invading the market shares of Sony and OV in the past.

Sony's mobile phone has not been able to adjust the IMX series sensors as well as some of its friends. In contrast, Samsung has the ability to adjust the imaging effects of the ISOCELL and IMX series sensors to be very similar for the same flagship machine supplied with hybrid CMOS. Samsung is more like a biological mother than Sony in imaging algorithm optimization, which can be seen from the era of Samsung Galaxy S4. DTI image quality enhancement technology on Sony CMOS is also suspected of copying ISOCELL pixel structure. Sony is no longer the all-around leading manufacturer in CMOS technology in the past. In addition to the suspected reference to ISOCELL design, Samsung has also introduced the dual pixel dual core focusing and phase focusing technology into smartphones first.

It is worth mentioning that without the competition between these manufacturers and Sony in the CMOS market share, it is estimated that the cost of today's image sensors will not be reduced. In addition, in the event of emergencies such as earthquakes and floods, not only the price of smart phones, including cameras and digital cameras, will fluctuate. We still remember the price increases in the past few years, and OV, Samsung and other manufacturers can share certain risks.

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