Optical Touch Display Panel Reset Voltage Control
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Solution Overview
Problem
The existing optical touch display panels suffer from false determination of touch events due to a low reset voltage level, leading to a low signal-to-noise ratio and increased probability of incorrect touch detection.
Innovation Solution
An optical touch display panel is designed with light-sensing touch units that include a light-sensing component, a storage capacitor, a signal reading component, and a charging component, where the charging component helps to elevate the reset voltage level of the storage capacitor, thereby increasing the voltage difference between dark and bright states, reducing false determinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the touch detection frequency is synchronized with the screen update frequency (frame rate), then the touch interface is synchronized with the display image, but the reset time for charging the storage capacitor is limited, resulting in a low reset voltage level and low signal-to-noise ratio
Solution Approach 1:
The patent applies preliminary action by performing the capacitor charging (reset) operation before the touch detection and display update processes. The charging component charges the storage capacitor to a predetermined voltage level in advance, ensuring that the capacitor is ready for accurate touch detection in the next frame without extending the overall frame time. This resolves the contradiction by preparing the system in advance rather than during the critical detection phase.
2Loss of time
If the reset voltage level of the storage capacitor is low, then the charging time can be shorter, but the voltage difference between dark and bright states becomes small, causing low signal-to-noise ratio and false touch detection
Solution Approach 1:
The charging component performs preliminary charging of the storage capacitor to a high reset voltage level before the touch detection phase. This ensures that when touch detection occurs, the capacitor has sufficient voltage headroom to produce a large voltage difference between dark and bright states, improving measurement precision without requiring extended charging time during the frame cycle.
Solution Approach 2:
The patent implements periodic charging action where the charging component periodically resets the storage capacitor voltage to a predetermined level at regular intervals (synchronized with frame rate). This periodic reset ensures consistent high voltage levels are maintained across frames, providing stable and accurate touch detection while keeping the overall time management within the frame rate constraints.
3Use of energy by moving object
If the voltage difference between dark state voltage and bright state voltage is small, then the power consumption can be reduced, but the signal-to-noise ratio becomes low, increasing the probability of false touch event determination
Solution Approach 1:
The charging component performs preliminary charging to establish a high reset voltage level before touch detection. This creates a large voltage difference between dark and bright states during the detection phase, improving signal-to-noise ratio and detection reliability. The power consumption is managed by confining the high-current charging operation to a brief preliminary phase rather than maintaining it continuously.
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
The enhanced reset voltage level effectively reduces the probability of false touch event detection by improving the signal-to-noise ratio, ensuring more accurate touch event detection.
Implementation Method 1
the light-sensing component 110 detects an environment light L and generates a light-sensing signal S1... when a finger 120 contacts or gets close to the light-sensing touch display panel 100 and blocks the environment light L being received by the light-sensing component 110, the light-sensing component 110 correspondingly generates a light-sensing signal S2... when a light pen 130 gets close to or contacts the light-sensing touch display panel 100, the light-sensing component 110, in addition to receiving the environment light L, also receives light emitted by the light pen 130
Data Source
AI summary
An optical touch display panel includes a plurality of light-sensing touch units and a position detecting circuit. Each light-sensing touch unit includes a light-sensing component, a storage capacitor, a signal reading component, and a charging component. The light-sensing component senses a light source to generate a sensing signal. The storage capacitor is connected electrically to the light-sensing component for storing the sensing signal. The signal reading component is connected electrically to the storage capacitor for reading a voltage of the storage capacitor to generate a reading signal. The charging signal is connected electrically to the storage capacitor for charging the storage capacitor to reset an electric charge record of the storage capacitor. The position detecting circuit is connected electrically to the light-sensing touch units for detecting a touch point on the optical touch display panel according to a reading signal output by each of the light-sensing touch units.