Transparent Capacitive Sensor for Display Cover Glass
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Solution Overview
Problem
Modern display screens face challenges in integrating biometric skin contact sensors without compromising the display's functionality or image quality, as existing solutions often require opaque components that obstruct light output from active regions.
Innovation Solution
A capacitive biometric skin contact sensor is designed to be integrated into a cover glass for display screens, featuring a substrate with gate drive channels, read-out channels, and sensor pixels with transparent capacitive sensing electrodes, allowing the sensor to overlay inactive regions and transmit biometric data while enabling light output from active regions to pass through.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an opaque biometric sensor is integrated into the display, then biometric sensing capability is achieved, but light output from active regions is blocked and image quality deteriorates
Solution Approach 1:
The sensor is designed with spatially varying optical properties: transparent regions are positioned over inactive regions to allow light transmission, while opaque regions are positioned over active regions to enable biometric sensing. This local differentiation resolves the contradiction by allowing the sensor to perform both functions in different locations.
Solution Approach 2:
The sensor is divided into multiple discrete regions with different optical characteristics - transparent portions and opaque portions - that can be selectively positioned over inactive and active regions respectively. This segmentation allows the sensor array to simultaneously maintain display quality and provide biometric sensing capability.
2Illumination intensity
If a transparent protective layer is made thinner to maximise image quality, then light transmission and visual quality improve, but protection for display components is reduced
Solution Approach 1:
The protective layer is constructed as a composite structure incorporating both transparent protective material and integrated sensor elements. This composite design allows the layer to maintain adequate thickness for protection while incorporating transparent regions that preserve light transmission and display quality.
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
The solution enables biometric data collection while maintaining the display's functionality and image quality, as the transparent components of the sensor allow light to pass through active regions, ensuring minimal impact on the visual quality of the display.
Implementation Method 1
each sensor pixel comprises a thin film transistor and an at least partially transparent capacitive sensing electrode coupled to the thin film transistor
Data Source
AI summary
An aspect of the disclosure provides a cover glass configured to overlie a display screen of a user equipment, UE, device, the cover glass comprising: a substrate arranged to overlie a said display screen for protecting said display screen, wherein the substrate has a display-facing surface and a user-facing surface; and a capacitive biometric skin contact sensor coupled to the substrate and configured to resolve the contours of skin proximal to the sensor, the sensor comprising: a plurality of gate drive channels; a plurality of read-out channels; a sensor array of sensor pixels, wherein each sensor pixel comprises a thin film transistor and an at least partially transparent capacitive sensing electrode coupled to the thin film transistor, and wherein each of the sensor pixels is coupled to both: (i) a gate drive channel to receive a scanning signal; and (ii) a read-out channel to provide a read-out signal; and conversion circuitry configured to process read-out signals received from sensor pixels to obtain biometric skin contact data therefrom; wherein the cover glass is arranged to couple to said UE device to enable transmission of biometric skin contact data from the conversion circuitry to a processor of said UE device.