Fingerprint Sensor Wedge Configuration for Thin Device Reliability
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Solution Overview
Problem
In miniaturized mobile devices with thinner display panels, the reduced distance between the fingerprint sensor and the user's finger makes it difficult to configure a large enough area for fingerprint acquisition, and the narrow space for dustproof members complicates the prevention of foreign substances from entering the sensor, potentially affecting other components like the battery.
Innovation Solution
The electronic device incorporates a frame structure that forms part of the front, rear, and side surfaces, including a recess for components, with a dustproof member strategically positioned between the frame and display to prevent foreign substances from entering the fingerprint sensor, while also addressing diffuse reflection issues from other components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the display panel is made thinner to achieve miniaturization, then the overall device size is reduced, but the distance between the fingerprint sensor and the user's finger becomes too short, making it difficult to configure a large enough area for fingerprint acquisition
Solution Approach 1:
The patent introduces a wedge-shaped air gap that tilts the fingerprint sensor relative to the display panel, creating a three-dimensional angular relationship. This dimensional change allows the sensor to capture fingerprints across a larger effective area despite the thin display thickness, as the angled configuration expands the sensing zone horizontally while maintaining vertical compactness.
Solution Approach 2:
The patent modifies the geometric parameters of the assembly by creating a non-uniform air gap with specific wedge angles (e.g., 5-15 degrees). By controlling the thickness gradient of the adhesive layer and the positioning of the fingerprint sensor at an angle, the effective sensing area is increased without increasing the overall device thickness, thus resolving the contradiction between miniaturization and fingerprint acquisition area.
2Reliability
If the bracket is processed extensively to create space for the dustproof member, then foreign substances can be prevented from entering the fingerprint sensor, but perforations may be formed due to machining errors and the bracket thickness is reduced to the breaking point
Solution Approach 1:
The patent introduces a separate dustproof member (such as a gasket or sealing ring) that acts as an intermediary element between the bracket and the fingerprint sensor. This dustproof member is positioned in the air gap to block foreign substances from entering the sensor, while the bracket itself requires minimal processing, thereby maintaining its structural strength and avoiding perforations from excessive machining.
Solution Approach 2:
The dustproof function is segmented from the bracket structure into a separate, dedicated dustproof member. This segmentation allows the bracket to maintain its original thickness and strength without being extensively processed, while the dustproof member specifically addresses the contamination prevention requirement. The dustproof member can be a separate ring, gasket, or barrier element positioned in the air gap.
3Reliability
If a dustproof member is mounted between the FPCB and the bracket, then foreign substances are prevented from entering the fingerprint sensor, but the narrow space complicates the configuration and may not effectively prevent substances from affecting other components like the battery
Solution Approach 1:
The dustproof member is designed with multi-functionality: it not only prevents foreign substances from entering the fingerprint sensor but also serves as a structural spacer to maintain the wedge-shaped air gap, provides thermal insulation, and blocks contaminants from reaching other components mounted in the bracket such as the battery. This universal approach simplifies the overall assembly by consolidating multiple protective functions into a single element.
Data Source
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AI summary
An electronic device includes: a housing including a window facing in a first direction and a rear plate facing in a second direction; a display including a first layer disposed on the window, a second layer disposed on the first layer and having a first opening, and a conductive layer disposed on the second layer and having a second opening corresponding to the first opening; an FPCB disposed on the display and having a third opening corresponding to the second opening; a frame structure disposed between the FPCB and the rear plate and having a fourth opening corresponding to the third opening; a fingerprint sensor having at least a portion inserted into the fourth opening and facing in the first direction; and a dustproof member disposed between the display and the frame structure within a region formed by the third opening.