Touchscreen Photoconductivity for Biometric Sensing
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Solution Overview
Problem
Current touchscreens cannot detect reflected light or sense changes in reflected light, necessitating additional hardware and modifications, which increase the bill of materials and complexity.
Innovation Solution
Incorporating a photoconductive material, such as graphene, into the touchscreen's drive lines and sense lines, allowing light reflected from a user's finger to generate a photocurrent that can be analyzed for biometric data, such as photoplethysmogram (PPG) signals, without requiring separate biometric sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional hardware and modifications are added to enable reflected light detection, then biometric sensing capability is improved, but device complexity and bill of materials increase
Solution Approach 1:
The patent combines the touchscreen functionality with biometric sensing by integrating a photoconductive layer into the existing touchscreen structure. The drive lines and sense lines of the touchscreen are utilized to detect reflected light, merging two functions (touch input and biometric sensing) into a single integrated system, thereby avoiding additional hardware while enabling photoplethysmogram detection
Solution Approach 2:
The touchscreen system is designed to serve multiple functions: it acts as both a touch input device and a biometric sensor. The same touchscreen infrastructure (drive lines, sense lines, and photoconductive material) is used for both touch detection and reflected light sensing, making the system universal and eliminating the need for separate dedicated biometric sensing hardware
2Reliability
If additional hardware and modifications are added to enable reflected light detection, then biometric sensing capability is improved, but bill of materials increases
Solution Approach 1:
The patent combines the touchscreen functionality with biometric sensing by integrating a photoconductive layer into the existing touchscreen structure. The drive lines and sense lines of the touchscreen are utilized to detect reflected light, merging two functions (touch input and biometric sensing) into a single integrated system, thereby avoiding additional hardware while enabling photoplethysmogram detection
Solution Approach 2:
The existing touchscreen infrastructure serves dual purposes: it performs its primary touch detection function while simultaneously serving as the sensing mechanism for biometric data collection. The photoconductive layer converts reflected light into electrical signals that are processed by the existing touchscreen controller, making the system self-sufficient and eliminating the need for separate biometric sensing components
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 the collection of biometric data, including heart rate and other physiological parameters, directly through the touchscreen, reducing the need for additional hardware and simplifying the integration of biometric sensing into existing touchscreen devices.
Implementation Method 1
Incorporating a photoconductive material, such as graphene, into the touchscreen's drive lines and sense lines, allowing light reflected from a user's finger to generate a photocurrent
Data Source
AI summary
Particular embodiments described herein provide for an apparatus to determine biometric data of a user including: a processing circuit configured to: generate a control signal relating to a control value for controlling a wavelength of emitted light of a light source; receive biometric input data based on reflected light from the skin of the user caused by the light of the wavelength emitted by the light source; and determine biometric data of the user based on the biometric input data; and an output interface configured to provide the biometric data of the user.