Fingerprint-on-Display Thermal Pixels Using Oxide Semiconductor Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing biometric sensors, particularly fingerprint sensors, face limitations in accuracy due to the physical principles used for reading fingerprint patterns and are susceptible to environmental variables, leading to issues with spoofing and inconsistent performance.
Innovation Solution
The integration of a micro heater and a micro temperature sensor, utilizing an oxide semiconductor material, operates on an active thermal sensing principle with capacitive touch sensing elements, enhancing anti-spoofing performance by combining active and passive thermal sensing modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fingerprint sensing principles are used, then device complexity is reduced, but measurement precision and reliability deteriorate due to susceptibility to environmental variables and spoofing
Solution Approach 1:
The patent combines multiple sensing modalities (capacitive touch sensing, active thermal sensing, and passive thermal sensing) into a single integrated sensor device. The capacitive touch sensing elements and thermal sensing pixels are integrated in the same device, allowing simultaneous acquisition of multiple biometric parameters which significantly improves measurement precision and anti-spoofing capability while managing device complexity through unified design
Solution Approach 2:
The sensor device performs multiple functions: capacitive touch detection, active thermal sensing, and passive thermal sensing. This multi-functionality allows the single device to capture various biometric characteristics (electrical properties, active thermal response, passive thermal distribution) simultaneously, enhancing measurement precision without requiring separate dedicated sensors for each modality
2Reliability
If active thermal sensing is implemented, then anti-spoofing performance is improved, but use of energy increases due to heating requirements
Solution Approach 1:
The active thermal sensing operates using periodic pulsed heating rather than continuous heating. The micro heater applies thermal pulses at specific intervals, and the transient thermal response is measured during these periodic cycles. This periodic operation mode reduces average power consumption compared to continuous heating while maintaining effective anti-spoofing performance through transient thermal characterization
Solution Approach 2:
The heating is applied partially in time (pulsed rather than continuous) and selectively to specific regions. The micro heater applies thermal energy only when needed for active thermal sensing measurements, and the heating duration and intensity are optimized to achieve sufficient thermal contrast for spoofing detection while minimizing overall energy consumption
3Measurement precision
If high-resolution thermal sensing is achieved, then measurement precision is improved, but manufacturing precision requirements increase
Solution Approach 1:
The oxide semiconductor material inherently provides the temperature coefficient needed for thermal sensing functionality. The material's natural property of changing electrical characteristics with temperature is utilized directly, eliminating the need for additional temperature coefficient adjustment steps during manufacturing. This self-service approach to achieving temperature sensitivity simplifies the manufacturing process while maintaining high measurement precision
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 achieves a high-resolution biometric sensor with extremely low false rejection and acceptance rates, providing robust anti-spoofing capabilities and improved accuracy under varying environmental conditions.
Implementation Method 1
a low power heat pulse is applied
Implementation Method 2
The oxide semiconductor material may have a temperature coefficient in a suitable range, for example, from −2 mV/° C. and −200 mV/° C.
Implementation Method 3
capacitive touch sensing elements
Data Source
AI summary
A sensor, a device, a system, and a method, for biometric sensing, are provided. Such a device or system includes a micro heater and a micro temperature sensor for at least active thermal sensing, which may comprise an oxide semiconductor material. The micro heater and the micro temperature sensor may be separate or combined in one pixel. The present disclosure also provides an out-cell type or an in-cell type of biometric sensor on display device, for example, an out-cell type or an in-cell type fingerprint sensor on display (FoD) device. The pixels for active thermal sensing include an oxide semiconductor material. The methods of making and the methods of using the sensors, the devices, or the system are also provided.