Touch Display Driving Circuit for Expanded Force Sensing Range
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Solution Overview
Problem
Conventional touch force sensing methods in display devices are inadequate for accurately categorizing the magnitude of touch force and processing user input based on the categorized force, as they fail to effectively sense touch force beyond a saturated capacitance state and do not expand the sensing range of touch force detection.
Innovation Solution
A touch display device with a plurality of first electrodes and a second electrode, where a driving circuit applies signals to both sets of electrodes and senses capacitance changes to detect touch force, using a reference value to differentiate between gap and contact area changes to sense touch force even after capacitance becomes saturated, thereby expanding the sensing range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional touch force sensing method is used, then touch force can be sensed within limited range, but sensing range becomes saturated and cannot detect further touch force magnitude changes
Solution Approach 1:
The patent divides the touch force sensing process into two distinct stages: gap sensing (measuring changes in distance between electrodes) and contact area sensing (measuring changes in electrode contact area). This segmentation allows the system to use different sensing mechanisms for different touch force magnitudes, preventing saturation and expanding the overall sensing range.
Solution Approach 2:
The patent transitions from one-dimensional gap sensing to two-dimensional sensing by incorporating contact area measurement. When the gap between electrodes becomes saturated, the system activates contact area sensing as an additional dimension, allowing continuous touch force detection beyond the original saturation point.
2Measurement precision
If only gap change sensing is used, then touch force can be detected initially, but sensing value becomes saturated and cannot categorize different touch force magnitudes
Solution Approach 1:
The patent introduces a reference value as an intermediary threshold that mediates between gap sensing and contact area sensing. When the sensed capacitance exceeds this reference value, the system switches from gap sensing to contact area sensing, ensuring continuous and accurate touch force detection without information loss.
Solution Approach 2:
The system continuously monitors the sensed capacitance value and uses feedback to determine whether to use gap sensing or contact area sensing. When the capacitance exceeds the reference value, the feedback mechanism triggers a switch to contact area sensing, maintaining accurate touch force categorization across all magnitude ranges.
3Device complexity
If conventional single-electrode sensing is used, then device structure remains simple, but cannot distinguish between gap changes and contact area changes
Solution Approach 1:
The patent segments the electrode system into first electrodes (on the display panel) and a second electrode (spaced apart), allowing independent sensing of gap changes and contact area changes. This segmentation enables the system to distinguish between the two types of capacitance changes while maintaining a relatively simple overall structure.
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
Enables accurate sensing and processing of touch force across a broader range, allowing for varied user inputs by distinguishing between capacitance changes due to gap and contact area changes, even after capacitance saturation, enhancing user input processing capabilities.
Implementation Method 1
sense at least one of a first capacitance between an object that comes into contact with the display panel and the first electrodes and second capacitance between the first electrodes and the second electrode
Data Source
AI summary
Disclosed are a driving circuit, a touch display device, and a method of driving the same. The touch display device for sensing a user's touch force may sense a capacitance change due to a change in a contact area on a display panel after a section in which a sensing value of a touch force based on a change in capacitance between first electrodes and a second electrode becomes a saturated state, thereby sensing the user's touch force even in a section where the change in the capacitance between the first electrodes and the second electrode is small. Accordingly, it is possible to expand a range in which a user's touch force can be sensed and acquire data on a user's touch force linearly indicated in the expanded range, so that touch force leveling becomes easy and various inputs based on the touch force can be processed.