TFT Sensor Array for Accurate Temperature and Light Detection
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Solution Overview
Problem
Existing display devices face challenges in accurately measuring temperature and ambient light due to variations in threshold voltage during mass production, affecting the accuracy of temperature detection and backlight dimming control.
Innovation Solution
The solution involves connecting two TFT elements in series, where one TFT element is for temperature detection and the other for ambient light detection, allowing for the accurate measurement of the threshold voltage, enabling precise temperature and ambient light sensing without additional sensors, and using integrated digital conversion circuits to reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed control voltage is used based on typical threshold voltage, then the device complexity is reduced, but the temperature measurement accuracy deteriorates due to threshold voltage variation during mass production
Solution Approach 1:
The patent applies preliminary action by measuring and storing the threshold voltage of each TFT element during the manufacturing process. This pre-measured threshold voltage is then used to calculate and set the control voltage specifically for that element, ensuring accurate temperature measurement without requiring complex real-time adjustments during operation.
Solution Approach 2:
The patent changes the control voltage parameter based on the measured threshold voltage of each TFT element. By adjusting the control voltage to be three times the measured threshold voltage (rather than using a fixed typical value), the system compensates for manufacturing variations and achieves accurate temperature measurement across all produced devices.
2Measurement precision
If separate sensors are provided for temperature and ambient light detection, then the measurement precision is improved, but the device complexity and cost increase
Solution Approach 1:
The patent makes the TFT element universal by enabling it to perform multiple functions: temperature detection, ambient light detection, and threshold voltage measurement. By controlling which parameter is measured through the same TFT element, the system eliminates the need for separate dedicated sensors, reducing device complexity and cost while maintaining measurement precision.
Solution Approach 2:
The patent merges the functions of temperature sensing, ambient light sensing, and threshold voltage measurement into a single TFT element. This consolidation allows one component to replace what would traditionally require multiple separate sensors and measurement circuits, simplifying the overall device architecture.
3Measurement precision
If additional sensors are added for accurate temperature and ambient light detection, then the measurement precision is improved, but the manufacturing cost increases
Solution Approach 1:
The patent applies self-service by using the TFT element's own electrical characteristics (threshold voltage, drain current) to perform sensing functions. The TFT element measures its own threshold voltage during manufacturing, and this self-measured value is used to configure accurate temperature and ambient light detection, eliminating the need for additional expensive sensing components.
Solution Approach 2:
The patent uses the electrical characteristics of the TFT element itself as the sensing mechanism, rather than copying or adding separate physical sensors. By measuring parameters like drain current and threshold voltage that are inherent to the TFT's operation, the system achieves sensing functionality without requiring additional hardware copies of sensing elements.
Data Source
AI summary
A TFT element for ambient light detection and a TFT element for temperature detection are connected in series. In a first period, a first switch element is off, and a second switch element is at a hi side, so that a threshold voltage of the TFT element for temperature detection is detected. In a second period, a first switch element is on, and a second switch element is at a low side, so that temperature is detected. In a third period, a first switch element is on, and a second switch element is at a hi side, so that ambient light is detected. An input voltage and a control voltage to each of the TFT elements are set by a voltage controller provided in a drive circuit based on the threshold voltage.