Fingerprint Sensor Input Filtering for Accidental Touch Rejection
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Solution Overview
Problem
Fingerprint sensors in portable terminals often detect unintended finger movements, leading to erroneous operations due to their placement on the rear surface and inability to differentiate between intentional and unintentional contacts, resulting in unwanted cursor movements and operation recognition.
Innovation Solution
A portable terminal with a fingerprint sensor that recognizes finger contact and movement, and a conversion unit that converts these into input events, ignoring movements and placements within predetermined time thresholds (e.g., 80 ms) to prevent erroneous recognition, thereby distinguishing between intentional and unintentional actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the fingerprint sensor detects all finger movements, then operation input functionality is enhanced, but erroneous operations occur due to unintentional contacts
Solution Approach 1:
The patent changes the temporal parameter by introducing a time threshold (e.g., 80ms) to differentiate between intentional and unintentional finger movements. This parameter-based differentiation allows the system to accept valid operations while rejecting erroneous ones, resolving the contradiction between enhanced functionality and operational accuracy
2Device complexity
If the fingerprint sensor is placed on the rear surface, then device integration is improved, but unintentional finger contacts increase
Solution Approach 1:
The patent applies temporal parameter analysis (time threshold) to distinguish intentional from unintentional contacts. This allows the rear-placed sensor to maintain its integration advantages while filtering out erroneous inputs caused by accidental touches during device handling
3Speed
If the fingerprint sensor detects rapid movements, then response speed is improved, but false detection of unintentional operations increases
Solution Approach 1:
The patent introduces a time threshold parameter that acts as a filter for detection precision. By setting this threshold (e.g., 80ms), the system maintains high response speed for legitimate operations while automatically filtering out rapid, unintentional movements that fall below the threshold, thus resolving the contradiction between speed and precision
Data Source
AI summary
A portable terminal includes a finger sensor that recognizes, in response to contact of a finger, the contact and a movement of the finger; and a conversion unit that converts the movement of the finger recognized by the finger sensor into an input event corresponding to an operation instruction to an application running on the portable terminal. If a period of time from recognition of release of the finger from the finger sensor to recognition of placement of the finger on the finger sensor is less than a predetermined amount of time corresponding to physical limitations of a human, the conversion unit does not convert to the input event the recognition of placement of the finger, and recognition of a movement of the finger until recognition of release of the finger after the recognition of placement of the finger.