“Recently, the smartphone camera “Allegro” became popular on Weibo. Whether a mobile phone can “play Allegro” has nothing to do with the quality of the mobile phone. The “Allegro sound” is the sound of the optical image stabilization structure leaving a gap, and most mobile phones with optical image stabilization can hear the “Allegro sound”, but the mobile phone “Allegro sound” is small and cannot hear the “Allegro sound”. It means that the phone does not have optical image stabilization. If you can hear the “Allegro sound”, it means that the optical image stabilization is actually inside the phone.
Recently, the smartphone camera “Allegro” became popular on Weibo. Whether a mobile phone can “play Allegro” has nothing to do with the quality of the mobile phone. The “Allegro sound” is the sound of the optical image stabilization structure leaving a gap, and most mobile phones with optical image stabilization can hear the “Allegro sound”, but the mobile phone “Allegro sound” is small and cannot hear the “Allegro sound”. It means that the phone does not have optical image stabilization. If you can hear the “Allegro sound”, it means that the optical image stabilization is actually inside the phone.
The reason for the matter is that a certain flagship mobile phone will make a “da da da” sound after shaking the phone, and this sound is nicknamed “Allegro sound” by peers. The “Allegro sound” here is actually the shaking sound of the lens anti-shake module. So why does the lens anti-shake sound appear? What are the types of lens anti-shake? Today we will explore this issue.
01 Why do I need anti-shake when taking photos with my mobile phone?
As we all know, when we use mobile phones to take pictures, the mobile phones will be displaced. In order to prevent the photos from being “fuzzy”, the anti-shake mechanism in the imaging system will intervene during the shooting. At present, the anti-shake mechanisms in mobile phones are mainly divided into two categories: optical anti-shake and (OIS) Electronic anti-shake (EIS).
Optical image stabilization (OIS)
The abbreviation OIS for optical image stabilization is the abbreviation for Optical image stabilization. The realization principle of this kind of anti-shake is to realize the effect of correcting the picture through the floating of the lens. The realization principle is to use the gyroscope inside the mobile phone to detect the movement, and to compensate the lens movement in time through the recognition of the processor, so as to effectively overcome the blurring of the shooting picture caused by external force.
Principle of optical image stabilization
In actual use, the mobile phone’s optical image stabilization has a better anti-shake experience in low-light environments, zooming and shooting in sports. But for mobile phones, simply having optical image stabilization is not completely capable of taking good photos, and the role of electronic image stabilization in shooting is also very important.
Electronic image stabilization (EIS)
Electronic image stabilization is precisely a software image stabilization technology, which is mainly designed to compensate for the shooting process through software design. When the shooting image is “fuzzy”, the electronic anti-shake algorithm will compensate for the blurred part.
Judging from the actual working principle of optical image stabilization and electronic image stabilization, the role of optical image stabilization will be greater. In addition, from the actual disassembly, the sensor integration of mobile phones is getting higher and higher, and optical image stabilization is from the lens. Anti-shake + sensor anti-shake is developed into integrated anti-shake, and the anti-shake mechanism is directly integrated into lens + sensor integrated anti-shake, which improves the anti-shake performance and reduces the difficulty of mass production. The sound produced by mobile phone shaking mainly comes from optical image stabilization.
02 The current mainstream optical image stabilization solution
There are currently three mainstream OIS optical image stabilization solutions on the market: suspension wire structure image stabilization, ball structure image stabilization, and memory metal optical image stabilization.
Suspended wire structure anti-shake
Suspended wire structure anti-shake is the most widely used optical anti-shake technology in mobile phones. The specific principle is that the lens assembly is fixed on a plane stabilization frame suspended by an electromagnetic field through 4 suspension wires of equal length. From the front, the sensor looks like the sensor is hung by the suspension wire. The suspension wire can be energized under the force of the magnetic field. Moving in any direction (moving direction and distance are generally calculated by mobile phone chips, gyroscopes, etc.), the displacement of the suspended wire structure is generally controlled within plus or minus 100 microns.
The principle of suspension wire structure is the same as that of SLR camera optical image stabilization, but the volume of the mobile phone camera is much smaller than that of the camera. The length of the suspension wire is shorter. The suspension wire structure can easily realize the movement of X axis and Y axis, but the Z axis movement (the lens moves back and forth) ) Requires the AF focus motor to move accordingly to compensate. The overall flexibility is insufficient, and the volume is difficult to control. In addition, magnetic accessories may also affect the suspension-type anti-shake.
Ball structure anti-shake
The anti-shake of the ball structure can be said to be developed for the shortcomings of the anti-shake structure of the suspension wire. The anti-shake of the ball structure removes the suspension wire structure and replaces it with a two-layer ball slide structure on the X axis and the Y axis, which solves the traditional The suspension wire structure anti-shake for Z-axis anti-shake is a problem that requires the participation of the focus motor. The working principle of the ball structure anti-shake is that the ball drives the entire lens module for anti-shake, and the distance between the Z-axis direction and the image sensor does not change during the working process.
Compared with the anti-shake of the suspension wire structure, the technical advantages of the anti-shake of the ball structure are embodied in: it can make a larger compensation angle; the displacement control is more accurate, the sensitivity is higher, and the stability is stronger; the power consumption is lower; the reliability Stronger: The slide rail structure has strong controllability, less wear, greater component strength, and lower failure rate; at the same time, the thickness of the camera is easier to control. At present, most high-end mobile phones use this kind of anti-shake structure.
Memory metal optical image stabilization
Memory metal optical image stabilization structure diagram
Memory metal optical image stabilization, as the name suggests, is an optical image stabilization method that controls the movement of the lens by adjusting the temperature of the memory metal. This technology is first launched on the P30 Pro. If the P30 Pro super-large main camera sensor uses traditional optical image stabilization technology, the volume of the sensor cannot be controlled, and the sensor’s sensitivity to the optical image stabilization feedback will also be reduced, and the metal image stabilization memory is also memorized. Another benefit of anti-shake is that the overall weight of the sensor is effectively controlled.
Traditional suspension wire anti-shake movement (picture left, picture) and memory metal anti-shake movement (picture right)
The memory metal optical image stabilization process rotates the entire lens module instead of only the lens during the anti-shake process. When the entire module is in anti-shake movement, the positions of the lens and the photosensitive chip remain relatively consistent. This brings the advantage of The image quality did not change much during the anti-shake process, and the image quality at the edge of the picture did not significantly decrease.
The reason why memory metal anti-shake can quickly achieve accurate anti-shake is that the deformation force of memory metal is a hundred or even a thousand times higher than that of ordinary suspension wire anti-shake. It is worth noting that the drive motor of the memory metal anti-shake is a metal wire with a very small diameter. Today, as mobile phone sensors are getting larger and larger, the memory metal anti-shake is more and more adapted to the development trend of smart phones.