A new Apple Patent filing reveals the use of a new Bimodal Reverse … – Patently Apple

It’s been rumored off and on again that Apple will someday provide reverse charging for an iPhone that could recharge accessories. An October 2020 (repeated again in 2021) MacRumors report pointed an FCC filing supporting such a feature. Then in February 2021, Mark Gurman claimed that wirelessly recharging accessories was unlikely in the near future.

Last Thursday, the US Patent & Trademark Office published a patent application from Apple that relates to a new wireless charging system using bimodal magnetic alignment components for alignment of devices. In the future, the back of a future iPhone could include this new wireless recharging system and enable  wirelessly recharge accessories such as AirPods and case, Apple Watch and more. Apple’s current wireless recharging on the back of an iPhone is limited to a large sized coil that can’t support charging smaller devices like an Apple Watch.

In Apple’s patent background they note that wireless charging technologies have been developed that exploit electromagnetic induction to charge portable electronic devices without the need for a charging cord. For example, some portable electronic devices can be recharged by merely resting the device on a charging surface of a wireless charger device. A transmitter coil disposed below the charging surface is driven with an alternating current that produces a time-varying magnetic flux that induces a current in a corresponding receiver coil in the portable electronic device.

The induced current can be used by the portable electronic device to charge its internal battery. Some portable electronic devices have been designed to not only receive power wirelessly but also to transmit power wirelessly to other portable electronic devices, such as accessory devices.

However, sometimes the alignment of the magnets can be impossible to set correctly. In a video from iDeviceHelp, we see how Apple’s wireless recharging works with a device like Apple’s MagSafe battery pack. However, when author tried to actually recharge AirPods in their case, it failed, even though the recharging light temporarily lit up. The author of the video surmised that it was likely only a software fix. Yet one of Apple’s latest patent applications published last Thursday makes it clear that it’s not as simple as a “software fix” but rather having to introduce a new kind of wireless recharging battery design using bimodal magnetic alignment components.

Bimodal Magnetic Alignment Components for Alignment of Devices

Apple further notes in their summary, that among other factors, the efficiency of wireless power transfer depends on the alignment between the transmitter and receiver coils. For instance, a transmitter coil and receiver coil may perform best when they are aligned coaxially. Where a portable electronic device has a flat surface with no guiding features, finding the proper alignment can be difficult.

Often, alignment is achieved by trial and error, with the user shifting the relative positions of the device and charger and observing the effect on charging performance.

Establishing optimal alignment in this manner can be time-consuming. Further, the absence of surface features can make it difficult to maintain optimal alignment. For example, if the portable electronic device and/or charger are jostled during charging, they may be shifted out of alignment. For these and other reasons, some electronic devices include annular magnetic alignment components (e.g., surrounding the inductive coils) that can attract and hold a pair of devices in a desired alignment. Such magnetic alignment systems can include two types of alignment components, referred to herein as “primary” and “secondary.” Each alignment component can include an annular (or ring-shaped) arrangement of magnets having a fixed arrangement of magnetic polarities such that alignment components of the two types attract each other.

For instance, a primary alignment component can have a quad-pole magnetic configuration in which the inner and outer annular regions have magnetic polarity oriented in opposing axial directions, while a secondary alignment component can have a dipole magnetic configuration with a radial magnetic orientation. When brought into proximity with each other, the primary and secondary alignment components can generate a mutually attractive magnetic force that can draw the alignment components (and the devices in which the alignment components are installed) into the desired alignment and/or resist dislodgement from the desired alignment.

In magnetic alignment systems of this kind, alignment components of like type (two primary alignment components or two secondary alignment components) magnetically repel each other. This can make it difficult to provide a “bimodal” device that can interchangeably attach to devices having either type of magnetic alignment component.

One option is to omit a magnetic alignment component from the bimodal device; however, a device without a magnetic alignment component cannot enjoy the advantages of magnetic alignment and attachment.

Another option is to provide two separate magnetic alignment components (one primary and one secondary), but this may also entail providing additional inductive coils and/or other electronic components, all of which can add to the size, weight, and manufacturing costs of the device.

Certain embodiments of the present invention relate to bimodal alignment components that can be included in a bimodal device. In a bimodal alignment component, the alignment magnets can be reoriented or shifted between a first attachment position in which magnetic orientation of the alignment magnets is complementary to a primary annular alignment component and a second attachment position in which magnetic orientation of the alignment magnets is complementary to a secondary annular alignment component. In this way, a device incorporating a bimodal alignment component can be interchangeably attached to other devices via either a primary annular alignment component or a secondary annular alignment component. 

Apple’s patent FIG. 4 below shows a simplified exploded view of a bimodal device; FIG. 7 shows a partial perspective view of a bimodal alignment component.


Apple’s patent FIGS. 22A and 22B above show simplified cross-section views of a bimodal alignment component in two different attachment positions.

This is a highly technical patent. For engineers and super geeks wanting to dive into the finer details, review Apple’s patent application number US 20220416590 A1.

Apple Inventors

  • Tim Rasmussen: Product Design Engineering Manager
  • Eric Jol: Senior Director, Product Design
  • Christopher Graham: Product Design Manager
  • Ruben Larsson: Product Design Manager
  • Eric Zhou: Product Design Engineer


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