Technical problems in the development of high-pixel camera modules

The electronic camera function is becoming the most important differentiating sign of major flagship smartphones, and even its limelight has a tendency to surpass the main chip platform of mobile phones. Mainstream flagship smartphones have adopted 13M pixel images, 5P, and even 6P lenses, and even the latest technologies such as closed-loop motor autofocus and optical image stabilization. By the end of this year, some manufacturers may launch 16M pixel mobile phones, and Chinese manufacturers can already provide the supply of these high-end camera modules, and the Chinese camera module industry has entered the world's first echelon.

　　 However, in recent years, with the huge market demand, the camera module industry has also expanded rapidly. The number of manufacturers has reached hundreds, and there are also dozens of large-scale companies. Can the future market still accommodate so many manufacturers? If these manufacturers fail to keep up with technological upgrading and economies of scale in the future, they will likely be eliminated soon. Let us first take a look at the main technical difficulties of 13M and the upcoming 16/20M camera module.

　　 The main technical difficulty of the 16/20M camera module

　　The technical leader of Sunny Optical, a leading camera module manufacturer in China, said that the main difficulties include the following:

　　* The production of components has become more difficult: the larger the aperture makes it difficult to improve the production yield of the lens. For example, the FNO1.8 lens, the most powerful manufacturer now has a yield rate of 20%. At the same time, the pixels are increased to 16M or even 20M, and 5P lenses will be difficult to meet the resolution requirements, which requires 6P and above lenses. The increase in the number of lenses is definitely a challenge for the assembly of the lens factory;

　　* Increased difficulty in supply chain resource integration: component technology is difficult, so there are few resource manufacturers that can produce high-pixel components. Who can integrate resources will dominate the market;

* Module assembly becomes more difficult: the higher the pixel, the higher the requirement for uniformity and consistency of the resolution, and the higher the requirements for the production line, especially the title (tilt) control in the module production process becomes a module The key to good team performance.

"To sum up, I believe that in the future, we must gain a firm foothold and develop in the module industry. It is not a question of who has the more money to invest in the COB production line. This is a matter of the first 5 years, but now it depends on which module If the factory has strong packaging capabilities and assembly testing capabilities, whoever can develop better in this industry." He believes.

　　 The technical director of Truly, another major camera module manufacturer in China, explained in detail the challenges facing the camera module industry in the future from another angle.

He explained that if it is only a simple pixel improvement, the technical threshold is mainly process improvement and quality control, including stain control, optical center alignment, tilt control, image color and function consistency correction, and image quality uniformity control. . However, if it is a closed-loop motor autofocus or optical image stabilization product, almost the entire production process of the camera module needs to be upgraded and modified, and the accuracy of the production line, the cleanliness of the production plant, and the design precision requirements will be more stringent. Generally speaking, the higher the pixels, the more difficult it is to manufacture the camera module. At present, a few camera module factories in China have experience in mass production of 113M, and the transition from 8M to 13M may involve strengthening production management. However, a large proportion of products with 13M or higher currently require closed-loop motor autofocus products and optical image stabilization products. The introduction and digestion of new processes and technologies is the biggest challenge. "At present, Truly has successfully mass-produced closed-loop motor autofocus products and optical image stabilization products, and is a leading enterprise in China," he said proudly.

　　 In addition to the challenges of these new technologies, camera module manufacturers are also facing another new issue: the tracking and development of some revolutionary and innovative camera technologies.

　　 The commercial prospects of revolutionary technologies such as array cameras

This year, some innovative and revolutionary camera technologies have been introduced to the public, such as array cameras, MEMS cameras, OIS and light field cameras. Some domestic module manufacturers are also tracking or developing this technology. What everyone is more worried about is these emerging technologies. Will new camera technology replace traditional camera technology? When will it be replaced?

　　 In this regard, the technical person in charge of Sunny Optical analyzed several revolutionary camera technologies that are currently popular. He pointed out that the array camera is still in the stage of industrial integration, and it is estimated that there is still a way to go before it is finally commercialized. It will be very good to be able to get up in the second half of next year; MEMS camera is a good thing, and it must be excellent in terms of size and power consumption. In the current VCM program. However, the problem of this solution is that the supply chain is single, which is not good for the development of the industry. For details, see the comparison below; the light field camera is similar to the array camera, but I personally think that it is unlikely to be applied to mobile phones. OIS optical image stabilization technology will be a mainstream technology next year, and it should become the preferred configuration solution for flagship phones of first- and second-tier customers. At the same time, he specifically mentioned that some 3D camera/optical zoom solutions are under study, and they may appear individually in the market next year, but they will not be mainstream.