Foldable Display Force Sensor Afterimage Compensation
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Solution Overview
Problem
Display devices with force sensors experience malfunctions due to afterimages caused by changes in the folding state, particularly in the folding area, leading to inaccurate touch force detection.
Innovation Solution
A display device with a force sensor system that includes touch cells and a touch driver to control threshold voltages based on the intensity of base forces, maintaining a constant reference force difference to prevent afterimages and ensure accurate touch force detection during state changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the display device is folded and unfolded, then the display device is portable and flexible, but afterimages are generated in the folding area causing malfunction of the force sensor
Solution Approach 1:
The touch driver detects base force in advance after folding/unfolding and adjusts the threshold voltage before normal touch detection resumes. This preliminary adjustment removes afterimages and prevents malfunction, ensuring accurate force sensing is restored before the device returns to normal operation.
Solution Approach 2:
The patent dynamically changes the threshold voltage parameter of the force sensor based on the detected base force intensity. By adjusting this electrical parameter in response to folding state changes, the system compensates for afterimage effects and maintains reliable touch detection across different device configurations.
2Measurement precision
If the threshold voltage is adjusted to remove afterimages, then the force sensor accuracy is improved, but the device complexity increases due to additional control mechanisms
Solution Approach 1:
The touch driver performs multiple functions: it detects base force, determines folding state changes, adjusts threshold voltage to remove afterimages, and enables normal touch detection. By consolidating these functions into a single controller, the patent improves measurement precision without proportionally increasing device complexity.
Solution Approach 2:
The system continuously monitors base force and uses this feedback to dynamically adjust the threshold voltage. This closed-loop control ensures accurate touch detection while maintaining relatively simple hardware by using software-based control logic in the touch driver to manage the adjustment process.
Data Source
AI summary
A display device is provided. The display device includes: a display panel including a first area, a second area, and a folding area between the first area and the second area, and a force sensor at one surface of the display panel. The force sensor includes a plurality of first touch cells overlapping the first area or the second area, a plurality of second touch cells overlapping the folding area, and a touch driver which controls a threshold voltage of the plurality of second touch cells on the basis of an intensity of a base force of the plurality of second touch cells.