Opportunity
The advancement of human-machine interaction, metaverse applications, and teleoperated robotics has created a pressing need for accurate and intuitive three-dimensional spatial perception. Conventional electronic skin technologies are predominantly limited to acquiring two-dimensional data through physical contact, which restricts their utility in dynamic, non-contact 3D environments. Existing solutions for 3D gesture recognition, such as those based on inertial sensors, strain gauges, ultrasound, or image analysis, often suffer from significant drawbacks. These include limited gesture recognition diversity, poor dynamic tracking capability, complex signal processing algorithms, bulky device form factors, high power consumption, and sensitivity to environmental changes. These limitations hinder seamless integration into everyday devices and applications, particularly where transparency, flexibility, and unobtrusive form factors are desired, such as on touchscreens, wearable devices, or robotic surfaces. There is a clear market and technological opportunity for a sensing solution that offers robust, real-time 3D spatial sensing in a compact, low-power, and environmentally adaptive package that can be invisibly integrated into various surfaces and systems.
Technology
This patent presents a transparent and flexible electronic skin with three-dimensional sensing capability, inspired by the active electrosensory system of Mormyroidea (weakly electric fish). The core innovation is a capacitive electric field sensor constructed from fully transparent and flexible materials. The device comprises a transparent flexible substrate (e.g., PDMS silicone), upon which a transmitter electrode and one or more receiver electrodes are patterned using a conductive transparent bio-gel. A dielectric layer separates these electrodes. A control circuit drives the transmitter electrode with a reference signal (e.g., a high-frequency square wave) to establish a quasi-static electrical near field around the sensor. When an object, such as a finger, enters this field, it distorts the field, altering the capacitive coupling. This distortion is detected as a change in the measurement signal at each receiver electrode. The control circuit processes these signals, using principles derived from a capacitive equivalent circuit model, to calculate the distance of the object from each receiver. By employing algorithms like least squares multilateration on data from multiple receiver electrodes (e.g., a central electrode surrounded by four peripheral ones), the system can reconstruct the object's precise three-dimensional coordinates and track its movement trajectory in space. The fabrication method utilizes molding and dispensing techniques with materials like PDMS and the specially formulated ionic bio-gel, enabling mass production via printing processes. A key technological feature is the use of the bio-gel for electrodes, which provides high stretchability and eliminates metal fatigue, combined with the transparent polymer matrix, resulting in a device that is not only functional but also highly integrable.
Advantages
- High Transparency and Flexibility: Exhibits over 80% light transmittance (410-1000 nm) and can be stretched up to 25% of its original length without significant performance degradation,
- enabling invisible integration on displays and curved surfaces.
- Robust 3D Sensing: Capable of accurate, non-contact 3D position and gesture tracking in air, with performance maintained even when the device is submerged underwater.
- Compact and Low-Power Design: Features a simple capacitive sensing principle, a streamlined control algorithm, and support for wireless (BLE) communication and charging, leading to a compact form factor and low power consumption.
- Excellent Durability: Withstands over 8000 cycles of folding and unfolding without performance loss, thanks to the fatigue-resistant conductive bio-gel electrodes.
- Manufacturing Scalability: The fabrication process based on molding and dispensing is compatible with printing technologies, facilitating low-cost mass production.
- Environmental Adaptability: Performance is less susceptible to changes in the working environment compared to optical or inertial systems, and it can leverage the human body as a ground reference for enhanced signal stability.
Applications
- Human-Machine Interaction (HMI): As a transparent overlay on touchscreens, monitors, or device surfaces for touchless 3D gesture control.
- Augmented/Virtual Reality (AR/VR) & Metaverse: For intuitive 3D manipulation and navigation in virtual spaces using hand and finger gestures.
- Wearable Electronics: Integrated into smart glasses, wristbands, or clothing for gesture-based control and spatial interaction.
- Robotics: Equipping robot arms or grippers with 3D proximity sensing for object detection, distance judgment, and delicate manipulation.
- Drones and Autonomous Vehicles: Providing obstacle detection and proximity sensing capabilities, even for thin objects like wires.
- Underwater Technology: Enabling gesture-based communication for divers in murky water and facilitating non-invasive monitoring of marine life behavior.
- 3D Modeling and Design: Serving as an input device for 3D computer-aided design (CAD) and digital sculpting applications.
