Laurence Kim
Laurence Kim
Wireless Power Marketing Intern
Published: January 23, 2022

It comes as no surprise that Virtual Reality and Augmented Reality technology have been booming in recent years and the market is projected to grow at more than 40% annually through 2030. Current options for smart glasses include audio glasses, social glasses, AR glasses, and XR glasses. Implementation to date has been bounded by a controlled environment due to technological and mechanical limitations. Renesas aims to develop technology that enables smart glasses to evolve into an everyday product.

To that end, the wireless power team at Renesas has engineered a wireless charging design into a pair of audio glasses to showcase as a benchmark for future smart glasses. The greatest advantage of implementing a wireless power design into smart glasses is removing any charging ports/pins that would otherwise make the product susceptible to common dust and water damage. In order for the smart glasses to be scaled into the general population, they need to first become lifestyle-friendly and this reference design implementation is a step in the right direction.

Off-the-shelf smart glasses with wireless charging addition

Figure 1. Off-the-shelf smart glasses with wireless charging addition

Here is a brief insight into the process of creating the prototype. First, the P9222-R receiver was implemented into the side of the smart glasses frame where the battery and existing chips are located. The connections from the receiver were appropriately wired across the frame so that it was connected to the receiver coil that was sanded into the nosepad. Afterwards, we tinkered around with a prototype stand that would be simple to place on a nightstand for charging that is both functional and design forward. A Tx coil is connected to a P9235A-RB transmitter on the nose bridge where the nosepad would be resting when put on the stand. We used a 3D printer to create a hollow platform for the nose stand that discretely hides the Tx chip as shown below.

Charging stand prototype

Figure 2. Charging stand prototype

There were a handful of hurdles that we encountered during the prototype process. This left a couple nuances regarding the design approach for consideration in future prototypes. As most wireless products implement a flat coil with a much larger surface area, they have leniency in contact positioning. However, the small form factor of the rod coil in our prototype’s Rx and Tx requires precise alignment between the coils. It would be ideal for future models to include magnetic positioning to ensure alignment of the contact points. The product path for this concept going forward includes a portable charging case and a 3D printed stand to conceal the coil inside.

The final version of the prototype ready for demonstration at CES 2022

Figure 3. The final version of the prototype ready for demonstration at CES 2022

Visit the Wireless Power landing page for more information on our wireless power products including technical documentation and reference designs.

Resource for AR/VR growth statistic can be found at:

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