Force Sensor Vertical Stacking Under Display
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Solution Overview
Problem
The integration of a force sensor with a fingerprint sensor within a portable electronic device's display often results in diminished pressure sensing performance due to the disposition structure, where the force sensor is placed either outside or surrounding the fingerprint sensor area.
Innovation Solution
A modified disposition structure for the force sensor is implemented, where it is placed on a separate surface of the circuit board with a dielectric layer and a second electrode layer connected to the ground, allowing for efficient pressure sensing performance regardless of the fingerprint sensor's location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the force sensor is disposed at an outer portion of the fingerprint sensor or in a structure enclosing the periphery, then the fingerprint sensor can be integrated within the display, but the pressure sensing performance of the force sensor is diminished
Solution Approach 1:
The force sensor is moved from a planar arrangement (on the same surface as the fingerprint sensor) to a vertical arrangement (on the opposite surface of the circuit board). This dimensional transition allows both sensors to coexist without spatial interference, resolving the contradiction between integration and pressure sensing performance.
Solution Approach 2:
The sensing system is segmented into two separate surfaces: the fingerprint sensor on one surface of the circuit board and the force sensor on the opposite surface. This segmentation eliminates the spatial conflict between the two sensors while maintaining their individual functionality.
2Area of stationary object
If the force sensor is disposed in an area corresponding to the fingerprint sensor, then the pressure sensing area is maximized, but the fingerprint sensor operation is interfered with
Solution Approach 1:
The force sensor is positioned on the opposite surface of the circuit board relative to the fingerprint sensor, utilizing the third dimension (depth/vertical space) to allow both sensors to occupy the same projected area without interfering with each other's operation.
Solution Approach 2:
The force sensor structure is nested within the overall sensor assembly, with the first electrode layer positioned to face the fingerprint sensor through the circuit board, creating a layered configuration that maximizes space utilization.
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
This configuration maintains pressure sensing performance and provides effective pressure sensing functionality to the user by optimizing the force sensor's placement and structure within the electronic device.
Implementation Method 1
a force sensor formed on a second surface of the circuit board. The force sensor includes a first electrode layer facing the second surface, a dielectric layer disposed under the first electrode layer
Data Source
AI summary
An electronic device including a force sensor integrated with a display is provided. The electronic device includes a display; a biometric sensor disposed under the display; a circuit board including the biometric sensor on a first surface thereof; and a force sensor formed on a second surface of the circuit board. The force sensor comprises a first electrode layer facing the second surface; a dielectric layer disposed under the first electrode layer; and a second electrode layer disposed under the dielectric layer and connected to a ground of the electronic device.