Display Sensor Circuit Switching for Biometric and Touch Recognition
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Solution Overview
Problem
Existing display devices struggle to efficiently integrate biometric information recognition and touch recognition functionalities without increasing complexity or thickness.
Innovation Solution
A display device incorporating a sensor with a sensing element and a sensor driving circuit, utilizing a switching circuit and driving circuit to output sensor scan signals with adjustable frequencies and modes for biometric and touch detection, allowing simultaneous biometric and touch recognition without a separate input sensing layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate input sensing layer is added for touch recognition, then touch recognition capability is improved, but device thickness and structural complexity increase
Solution Approach 1:
The patent combines biometric information recognition and touch recognition functionalities into a single sensor layer. The sensor layer includes sensing elements that can detect both biometric information (through capacitance changes) and touch inputs (through voltage changes), eliminating the need for separate sensing layers and reducing overall device complexity while maintaining both functionalities
Solution Approach 2:
The sensor layer is designed with multi-functional sensing elements that can perform both biometric information recognition and touch recognition. The sensing elements respond to different types of inputs (biometric vs. touch) by producing distinguishable signal characteristics, allowing a single component to serve multiple purposes without requiring additional specialized layers
2Length of stationary object
If biometric information recognition and touch recognition are integrated in a single sensor layer, then device thickness is reduced, but detection precision for both functions may deteriorate
Solution Approach 1:
The patent applies different driving frequencies to different detection modes within the same sensor layer. Biometric information recognition uses a first driving frequency while touch recognition uses a second driving frequency. This frequency differentiation allows the sensing elements to distinguish between the two types of inputs locally in the frequency domain, maintaining high detection precision for both functions despite using the same physical sensing elements
Solution Approach 2:
The sensor driver dynamically switches between different driving frequencies based on the detection mode. The system can transition between biometric information recognition mode and touch recognition mode by changing the driving frequency, allowing the same hardware to optimize its performance for the current task while maintaining thin device structure
3Measurement precision
If different driving frequencies are used for biometric and touch detection, then detection accuracy is improved, but circuit complexity increases
Solution Approach 1:
The sensor driver automatically selects and switches between different driving frequencies based on the current detection mode without requiring complex external control circuits. The system self-manages the frequency switching by monitoring the detection mode state, reducing the need for additional control logic and simplifying the overall circuit architecture while maintaining the ability to use different frequencies for different detection modes
Data Source
AI summary
A display device includes: a pixel including a light emitting element; a sensor including a sensing element and a sensor driving circuit; and a sensor driver to output a sensor scan signal to the sensor driving circuit. The sensor driver includes: a switching circuit connected between a first input terminal for receiving a first clock signal of a first operating frequency and a first clock node, and to output a first filtering clock signal of a second operating frequency to the first clock node in response to a first enable signal; and a driving circuit to output the sensor scan signal in response to the first filtering clock signal of the first clock node.