Several interesting patents from Microsoft were discovered in the USPTO directory, mainly involving a Surface laptop with a trackpad that doubles as a speaker. The product described in the Surface Laptop's trackpad patent is very unique compared to devices currently on the market. For example, Apple's MacBook has a haptic engine (TapticEngine) for tactile feedback, but it cannot double as a speaker. The ASUS ScreenPad has an interface to adjust the volume, but it cannot play sound.
Microsoft's idea is to turn a regular trackpad into a speaker, allowing for an impressive audio experience on a Surface laptop running Windows 11.
The patent application is titled "HAPTICTRACKPADLOUDSPEAKER" and is about a Surface Laptop that introduces a speaker based on a tactile trackpad. The patent was announced by UPSTO on November 14, 2024, and submitted by Microsoft on May 12, 2023.
Surface laptop with trackpad that doubles as speaker
According to my analysis, the Surface Laptop's trackpad doubles as a speaker. At the same time, it's a regular touch-sensitive trackpad for controlling Windows 11 and even generating tactile feedback. Tactile feedback refers to the vibration or click that occurs when a button is pressed on a glass panel.
So how does it work? According to the patent filing, the trackpad is made of glass and supports tactile touch motors. We then installed elastomeric spacers under the PCB, which act like springs and allow the trackpad to vibrate in the Z direction (vertical direction) and down.
Uniquely, Microsoft's patented haptic motor can handle both the low-frequency vibrations of tactile feedback (less than 400Hz) and the high-frequency vibrations of audio playback (400Hz to 10,000Hz).
The patented Surface Laptop's trackpad area doubles as a speaker diaphragm. The speaker diaphragm is the part of the speaker that produces sound through vibration. It moves up and down, creating a sound you can hear.
As a result, the trackpad is capable of handling light to medium levels of music, such as playing songs and handling notifications or audio cues, just like a regular speaker. I also noticed that the audio frequencies range from 400Hz to 10kHz, covering most of the range required for music, speech, and Windows 11 operating system sounds.
When reading the patent, it's not hard to notice that Microsoft has designed two modes for the trackpad-based speaker.
The first mode is called piston mode and is used for low frequency sounds such as speech or bass. Then there's distributed mode (which produces sounds above 3kHz), and the Surface Laptop should be able to handle higher frequency sounds.
The patent explains that a spring-mass system, tuned spacers, and a flexible surround allow the trackpad to transition smoothly between the two modes. As a result, the system "optimizes resonance for haptic feedback frequencies below 400Hz" and is capable of "outputting audio from 400Hz to 10kHz."
It’s also worth noting that Surface Laptop does not abandon traditional audio or speaker systems, but instead uses trackpad-based speakers. The device is likely to come with a multi-channel audio system, and the sound coming from the trackpad area will improve the overall music experience.
This is just a patent application at the moment, so it may or may not come to fruition, like most other ideas. According to ZacBowden, Microsoft is currently busy preparing Surface products with Intel Lunar Lake. New innovations or unique hardware may not appear anytime soon.