Original article here: https://gori.me/iphone/iphone-news/161745
(Translated using google translate)
TDK's TMR Sensor is the Secret to iPhone Cameras, Tim Cook Praises About Japanese Technology
TDK reveals thirty years of technology accumulation and manufacturing process that competitors cannot imitate at the first release of Apple Yokohama Technology Center
Apple CEO Tim Cook visited the Apple Yokohama Technology Center (YTC) in Tsunashima, Yokohama, during his visit to Japan. This is the first time that the facility has been opened to the public, and the reality of a state-of-the-art research and development center with about 6,000 square meters of lab space and a clean room has been revealed.
On the same day, YTC presented four of Apple's leading companies—TDK, AGC, Kyocera, and Sony Semiconductor Solutions— that support Apple’s innovation. Tim Cook told reporters, “Apple will never be happy with the situation. Continue to ask for something better. The same goes for Japanese companies. We will never be satisfied and will continue to develop with the aim of always further advancement,” he said, emphasizing the importance of collaborative relationships with Japanese companies.
The partnership between TDK and Apple began before the first iPod and has been in a long-term relationship for more than three decades. Today, almost all Apple products use TDK technology, and contribute to a wide range of fields, including batteries, pass filters, inductors, microphones, and various sensors.
It’s worth noting that TDK uses 100% renewable energy in all of its products it manufactures for Apple products. In the background of the beautiful photo shoot of the iPhone, which is usually used casually, and the ultra-compact part called the TMR sensor developed by TDK functions as a technology that all iPhone users benefit from.
TMR sensor stands for “Tunnel Magnetoresistance Sensor” and is an ultra-small sensor that detects changes in magnetic fields with extremely high sensitivity. It is so small that it contains fifty thousand wine glasses in a glass of wine, and it is a size that is almost invisible to the naked eye.
The principle of operation of this sensor applies quantum mechanical phenomena. To put it simply, it is a structure in which an ultra-thin insulator is sandwiched between two magnetic materials , and the electrical resistance changes dramatically due to changes in the external magnetic field. Compared to conventional Hall elements, the TMR sensor has reached about a hundred times the sensitivity of the TMR sensor, and it is characterized by extremely clear reactions such as "zero or one".
The experience of automatically focusing on the moment you launch the camera app on your iPhone and point the lens at the subject will be "natural" that many users feel on a daily basis. However, in this background, the TMR sensor accurately grasps the position of the lens in a thousandth of a second.
The specific mechanisms are as follows. When the lens moves back and forth, a small magnet moves with the lens. The TMR sensor detects the distance change with this magnet as a change in the magnetic field as a change in the magnetic field, and instantly grasps where the lens is now. The camera system makes appropriate focus adjustments by "detecting the position" rather than measuring the distance.
The TMR sensor, which was first used for autofocus applications on the iPhone X, has also been applied to the sensor shift image stabilization (OIS) from the iPhone 12 series. The minute movement due to the camera shake is also instantly detected, and the sensor itself is operated to correct it.
The latest iPhone 17 series also uses TMR sensors for the center stage function of the front camera, which detects the fine movement of the lens in real time with a sensitivity of 100 times more than general hall elements.
An easy example of an easy-to-understand TMR sensor is the joystick of the game controller. In the conventional joystick, a mechanical part called a "potension meter" is used, and the angle is detected by physical contact.
On the other hand, joysticks using TMR sensors operate non-contact , which greatly improves response speed and accuracy. In addition, since there is no mechanical wear, it also realizes durability that does not deteriorate in accuracy even if it is used for a long time.
The structure of the TMR sensor itself can be understood by the competitors when it is disassembled. However, it is very difficult to actually produce an equivalent product. The reason is TDK’s proprietary manufacturing process technology.
Semiconductor-based equipment is used for manufacturing, but it is not the equipment itself that is important. Combining multiple specialized technologies such as TMR deposition, magnetic material plating, and dry etching, the process of creating a unique layered structure that detects the magnetic field from which direction it detects the magnetic field from and which direction does it not perceives it is at the core.
Modern smartphones are becoming thinner, and many magnets are used inside. There may be concerns about whether the delicate TMR sensor will work properly in this environment.
TDK cooperates closely from the customer's design stage to propose optimal sensor placement and design . The influence of the magnetic field is rapidly weakened by simply securing 1cm of physical distance, so the interference problem can be solved with proper design. He visits Cupertino fourteen times a year, and his close work with Apple’s camera team is proof of that.
TDK has leveraged ninety years of expertise in magnetic materials to establish this process technology. The TMR sensors manufactured at the Asama Techno Plant in Japan also have a sustainable manufacturing system using 100% renewable energy.
The background of each photo that iPhone users casually take is the result of such a long-term accumulation of Japanese precision technology and technology. TMR sensors are by no means a prominent component, but they will continue to evolve as an important technology that supports the modern smartphone experience.
