Capacitive Skin Contact Sensor With Color-Filtered Pixel Array
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Solution Overview
Problem
Optical biometric sensors require a transparent region for imaging, limiting device design and appearance, and capacitive sensors lack color filtering capabilities, restricting design flexibility.
Innovation Solution
A capacitive biometric sensor with a color filter layer and optically reflective elements, allowing for non-transparent appearance while maintaining skin contact sensing functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent region is included for optical imaging, then optical biometric sensing is enabled, but device design freedom and appearance are limited
Solution Approach 1:
The patent replaces the optical imaging system with a capacitive sensing system. Instead of using optical sensors that require transparent regions to capture images of the skin, the invention uses capacitive sensor pixels that detect skin contact through electrical field interactions. This substitution eliminates the need for transparent regions while maintaining biometric authentication capability, thereby freeing device design from the constraint of incorporating transparent areas.
Solution Approach 2:
The patent introduces color filter layers on the sensor pixels to enable customizable appearance. By adding red, green, or blue color filters to the capacitive sensor pixels, the device can display colored patterns or images on the sensor surface. This allows the sensor to have a non-transparent, colored appearance that matches various device aesthetics while still functioning as a capacitive biometric sensor, thus enhancing design freedom.
2Reliability
If capacitive sensor pixels are used without color filtering, then skin contact sensing is achieved, but design flexibility and appearance customization are restricted
Solution Approach 1:
The patent applies color filter layers to the capacitive sensor pixels to enable appearance customization. Each sensor pixel can be equipped with different color filters (red, green, blue) or no filter at all, allowing the sensor surface to display various colors and patterns. This maintains the skin contact sensing functionality while enabling the device to match different aesthetic requirements, thereby enhancing design flexibility.
Solution Approach 2:
The patent applies color filtering at the pixel level, allowing different portions of the sensor surface to have different color properties. By segmenting the sensor array into individual pixels that can independently have color filters applied, the system achieves granular control over appearance while maintaining uniform capacitive sensing functionality across the entire sensor surface.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables greater design freedom for electronic devices by providing capacitive biometric skin contact sensing with customizable colors and reflective properties, enhancing user interaction without compromising functionality.
Implementation Method 1
each sensor pixel is formed of a plurality of layers including an optical colour filter layer arranged to filter one or more colours of light
Implementation Method 2
the sensor may comprise at least one optically reflective component configured to reflect light back towards the user (and through the colour filter)
Data Source
AI summary
Disclosed herein is a skin contact sensor comprising a sensor array of sensor pixels, wherein: each sensor pixel comprises at least one thin film transistor, TFT, and a sensing electrode; a top surface of the sensor array provides a contact surface for contacting by an object to be sensed; and each sensor pixel is formed of a plurality of layers including an optical colour filter layer arranged to filter one or more colours of light.