Reading Circuit Compensation for LTPS Touch Panel TFT Threshold Variations
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Solution Overview
Problem
Conventional touch panel sensors using low temperature poly-si (LTPS) technique have sensitivity issues due to varying threshold voltages of thin film transistors (TFTs) at different positions, leading to inconsistent light intensity readings.
Innovation Solution
A reading circuit comprising a detection module, a first transistor, and a compensation module, where the detection module detects light intensity and the compensation module adjusts the threshold voltage of the transistor to ensure consistent readings across different TFTs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TFTs are used to read detection results from sensors, then the sensitivity is improved, but the threshold voltage varies at different positions leading to inconsistent readings
Solution Approach 1:
The patent introduces a compensation transistor with adjustable threshold voltage parameters to counterbalance the threshold voltage variations of reading TFTs. By changing the electrical parameters (threshold voltage) of the compensation transistor, the system achieves consistent light intensity readings across different sensor positions despite TFT manufacturing variations.
Solution Approach 2:
The compensation transistor acts as an intermediary element between the sensor and the output circuit. It mediates the signal by compensating for threshold voltage variations, ensuring that the final reading reflects the actual light intensity rather than TFT manufacturing variations.
2Area of stationary object
If touch panels are used as input devices, then usable space is increased, but manufacturing precision of TFTs varies leading to threshold voltage inconsistencies
Solution Approach 1:
The compensation transistor's threshold voltage parameter is specifically adjusted to compensate for manufacturing variations. This parameter change approach allows the system to maintain consistent performance across the large area of the touch panel despite variations in TFT manufacturing precision.
Solution Approach 2:
The compensation transistor is designed and configured in advance to counteract expected threshold voltage variations. This preliminary compensation action ensures that reading consistency is maintained across the entire touch panel area before actual operation begins.
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 solution enables accurate and consistent light intensity readings across TFTs with varying threshold voltages, enhancing the reliability of touch panel systems in electronic devices.
Implementation Method 1
The detection module detects a light
Data Source
AI summary
A reading circuit including a detection module, a first transistor, and a compensation module is disclosed. The detection module detects a light. The first transistor transforms the detection result for generating a current signal. The compensation module compensates a threshold voltage of the first transistor.