Apple has been granted a patent (number US 11886253 B1) for “Magnetic Field Adjustments To A Magnetic Latch For Producing Accurate Kinematics In A Computing Device” with the goal of making its Mac laptops and iPads are as light and comfortable to use as possible.
Kinematics is a subfield of physics, developed in classical mechanics, that describes the motion of points, bodies, and systems of bodies without considering the forces that cause them to move
Alternative methods of accessing the internet and performing computing-related work tasks are becoming common, e.g., using tablets or standing workstations. Few studies examine postural differences while using these alternative methods.
About the patent
In the patent Apple notes that millions of laptop computers are manufactured and sold every year throughout the world. The clamshell design that separates the base portion of the laptop computer and the display portion is widely recognized and provides an effective mechanism to protect the display surface when the laptop computer is placed in a closed configuration for transport or storage.
The display portion is typically attached to the base portion by means of a hinge or hinges. The opposite edge of the display portion commonly includes some kind of retaining mechanism to ensure that the display portion and base portion do not open inadvertently.
Some modern retaining mechanisms that have replaced many mechanical latching mechanisms use magnetic fields to retain the laptop computer in a closed configuration. For example, a magnetic element in the display portion of the laptop computer is attracted to a magnetic element in the base portion of the laptop computer. The attractive force between the corresponding magnetic elements opposes the inadvertent opening of the laptop computer.
Apple says that the appearance of the laptop computer may meet a specific design goal because the structural components of the magnetic retaining mechanism aren’t visible to a user of the laptop computer. This can improve the user experience (UX) related to a computing device compared to a similar device with a visible mechanical latching mechanism.
However, sometimes such mechanisms result in a heavy laptop. Such a device may also be tricky to open if the magnetic field is too strong. Apple says that “what is needed is a technique for calibrating magnetic elements to improve the tolerances related to kinematic forces experienced by a user of the computing device.”
Summary of the patent
Here’s Apple’s abstract of the patent: “his application relates to improving kinematics in a computing device such as a laptop computer. A magnetic latch mechanism includes a magnetic array and an attractor plate. The magnetic array is secured in a top portion of the laptop computer and the attractor plate is secured in a base portion of the laptop computer. An attractive force of the magnetic latch mechanism is calibrated by selectively demagnetizing a portion of one or more magnetic elements in the magnetic array to reduce the attractive force proximate a target force.
“The calibration technique can include exciting a demagnetizing element, such as a pair of conductive coils, with a short, high frequency demagnetization pulse to create a demagnetized zone within the magnetic array that is completely demagnetized, irrespective of unit to unit variations of magnetic properties in the initially magnetized magnetic array. This technique ensures an accurate kinematic user experience.”