Rollable Display Pinion Rotation Sensing With Hall Sensor Feedback
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Solution Overview
Problem
Existing electronic devices with flexible displays face challenges in accurately detecting the movement and rotation of the display area, which is crucial for changing the display size and user experience, due to interference from surrounding signals.
Innovation Solution
The electronic device incorporates a rack gear, pinion gear, actuator, magnet, and hall sensor to detect the rotation angle of the pinion gear, using magnetic force changes to identify the movement and direction of the flexible display, thereby enhancing the detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a flexible display is used to enlarge the display area, then the display size can be increased, but the detection accuracy of display movement is reduced due to signal interference
Solution Approach 1:
A magnet is attached to the shaft and a hall sensor is used to detect magnetic field changes, serving as an intermediary detection mechanism that is not affected by the electromagnetic interference from the flexible display's driving signals, thereby resolving the signal interference problem while maintaining detection accuracy
Solution Approach 2:
The patent replaces optical or electrical detection methods with a magnetic field-based detection system using a hall sensor and magnet, which is immune to the electromagnetic interference generated by the flexible display's driving circuits, thus solving the measurement precision problem
2Measurement precision
If the hall sensor is positioned close to the pinion gear for accurate detection, then detection accuracy improves, but the internal space of the device increases
Solution Approach 1:
The hall sensor is positioned in a direction perpendicular to the shaft rather than radially close to the pinion gear, changing the spatial dimension of detection. This allows accurate detection of magnetic field changes caused by shaft rotation while maintaining a compact internal space configuration
3Measurement precision
If the magnet is positioned close to the pinion gear for better magnetic coupling, then detection sensitivity improves, but the mounting complexity increases
Solution Approach 1:
The magnet on the shaft serves multiple functions: it generates the magnetic field for detection, indicates shaft rotation position, and can be integrated with the existing shaft structure. This multi-functionality improves detection sensitivity while avoiding additional mounting complexity
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 solution allows for precise identification of the flexible display's movement, improving the display area's size adjustment and user environment, while optimizing internal space usage by fixing the magnet and hall sensor at designated positions.
Implementation Method 1
a hall sensor spaced apart from the pinion gear in a direction perpendicular to the shaft, and configured to detect a magnetic force transmitted from the magnet through the shaft and the pinion gear
Data Source
AI summary
An electronic device includes a first housing, a second housing slidably coupled to the first housing, a rollable display configured to be enlarged or reduced based on a movement of the second housing, a rack gear disposed on the second housing, a pinion gear driven in engagement with the rack gear and including a plurality of teeth, an actuator configured to rotate the pinion gear and coupled with the pinion gear by a shaft, a first magnet surrounding at least part of the shaft, and spaced apart from the pinion gear along the shaft, and a hall sensor spaced apart from the pinion gear in direction perpendicular to the shaft, and a processor, wherein the processor is configured to obtain data related to a change in the magnetic force using the hall sensor and identify a rotating angle of the pinion gear based on the data related to a change in the magnetic force.