The Position Of Image Sensor In The Optical Industry

By Author: Alan
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The optical camera module is mainly composed of an image sensor, a lens, a voice coil motor, and an infrared cut-off filter. Among them, the image sensor is the core component, accounting for more than 50% of the cost of the entire camera module. The rise and fall of the optical industry is the rise and fall of image sensors.

In 2000, the first mobile phone Sharp J-SH04 with a camera came out, followed by the first Motorola C975 with a front camera; the LG P925 was released in February 2011, the world’s first dual-camera support mobile phone. In 2018, Huawei P20 opened the era of dual rear cameras. In 2019, Huawei P30 used rear four cameras. The 20-year-old P40 Pro upgraded the rear cameras to 5, further accelerating the process of multi-camera.

It is not accidental that the mobile phone camera is developing in the direction of multi-camera, it has its inherent logic. Due to size limitations, a single camera in a mobile phone will inevitably not be able to compete with professional photography equipment. After the introduction of multi-camera, each camera division of labor and cooperation, with the cooperation ...
... of algorithm software, has the advantages of main camera + wide-angle + telephoto + blur, and has become the main configuration of Android phones. With different lens combinations, the multi-camera module has the advantages of optical zoom, background blur, and low-light shooting, which greatly improves the shooting effect.

In 2019, the total number of global smartphone cameras reached 4.4 billion, with an average of 3.21 cameras per mobile phone. The penetration rate of the three-camera market has increased rapidly. At present, Samsung has the highest penetration rate of mobile phones with three cameras and above, reaching 27%, while Huawei ranks second with 23%. The increase in the number of mobile phone cameras has gradually promoted the improvement of 3D imaging quality such as “wide-angle”, “telephoto”, “macro” and “blur”, and at the same time promoted the steady growth of the market size of camera vision solutions.

In addition to multi-shots, high-resolution optical lenses are still the general trend. As one of the most concerned parameters of consumers, pixels have rapidly developed from the 110 megapixels at the beginning of mobile phones equipped with cameras to multi-megapixel cameras to become the mainstream. In December 2018, Huawei released the Nova 4, the first 48-megapixel main camera phone. By 19, 40/48MP cameras had become the mainstream in the mobile phone market. Xiaomi's CC9 pro released in November 19 is equipped with a 100-megapixel rear main camera for the first time, opening the 108MP post-camera era.

In the past, mobile phone lenses used pure plastic lenses. With the upgrade of lenses driven by pixel enhancement, the number of plastic lenses used in cameras continued to increase. At this stage, mobile phone lenses have been upgraded from 5, 6 to 7 and 8 lenses. The increase in the number of lenses will undoubtedly increase the thickness of the whole machine. With the upgrade of the pixels of the mobile phone camera, the aperture becomes larger, and the plastic lens is imaging There are bottlenecks in optical performance such as sharpness and distortion. After 6 lenses in mobile phone lenses, the glass-plastic hybrid lens solution began to appear. One glass lens plus five plastic lenses or two glass lenses plus three plastic lenses can achieve the function of seven lenses.

The glass-plastic hybrid lens has many advantages and may become the mainstream lens solution in the future. The current production processes of glass lenses mainly include molded glass, WLO and WLG. Among them, molded glass has achieved mass production due to its mature technology and low cost. The glass-plastic hybrid lens replaces some plastic lenses with glass lenses. Compared with plastic lenses, glass lenses have higher light transmittance and greater brightness, which can improve the image quality, reduce the number of lenses and reduce the thickness of the lens. Since LG adopted a glass-plastic hybrid lens in 2017, the glass lens processing technology has gradually matured and the cost has been reduced, and it has now begun to be applied on a large scale in mobile phone terminals.

The lens has been upgraded and diversified, and large apertures and ultra-wide angles have also become new trends. The aperture is a device used to control the amount of light passing through the lens and entering the photosensitive surface of the body. Generally speaking, the size of the aperture is determined by the lens aperture and focal length. After the light passes through the lens, it irradiates the CMOS sensor through the aperture.

The large aperture can achieve the background blur, and at the same time increase the shutter speed to effectively stabilize the image to capture the dynamic picture. The larger the aperture of the lens, the more light enters through this aperture per unit time, the richer the information obtained by the photosensitive element, and the better the effect of the final photo. The larger the aperture will cause the chromatic aberration and dispersion of the light to increase during the refraction process, and higher requirements are placed on the lens manufacturer's optical design ability (correction of aberration) and assembly and debugging ability (to ensure the accuracy of coaxial assembly).

When many manufacturers promote the camera performance of a mobile phone, they often emphasize its camera pixels, aperture and other parameters. For example, the iPhone 12 Pro will be equipped with an F/1.6 large aperture camera.

The ultra-wide-angle lens has a wide field of view, and unlike fisheye lenses that has strong distortion, it is a lens that eliminates the distortion very well. The ultra-wide-angle lens has the characteristics of a strong sense of spatial depth of the shooting picture, a long depth of field, and a wide range of shooting scenes. The difficulty of designing a wide-angle lens is that the edge of the picture will be distorted by the refraction of the lens. Therefore, a more sophisticated lens combination is required to optimize the optical design, use high-quality optical lenses, and process the lens imaging effect through post-processing algorithms to achieve a better wide-angle Effect.

SLR cameras can achieve zooming through lenses with different focal lengths, but mobile phone cameras cannot change lenses. The penetration of multiple shots gives mobile phones the ability to shoot at multiple focal lengths. The telephoto lens can present the distant scene more realistically without loss of image quality.

Related article:https://www.utmel.com/blog/categories/sensors/image-sensor-how-do-ccd-and-cmos-sensors-work