Pixel Temperature Sensor Circuit Using TFT Off-Current Difference
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Solution Overview
Problem
Micro-LED displays face challenges in thermal management due to high brightness, leading to potential damage from accumulated heat, and existing temperature monitoring methods are costly and complex, limiting peak brightness and display performance.
Innovation Solution
A temperature sensor circuit using low-temperature polycrystalline oxide (LTPO) thin film transistors measures temperature changes within pixels by monitoring off-current differences between p-type LTPS and n-type oxide semiconductor transistors, without additional components, and integrates a gate driver for real-time monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If dynamic temperature monitoring is implemented to achieve best performance without thermal damage, then display performance and brightness are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The temperature sensor circuit is merged with the pixel circuit by sharing common electrodes (source/drain electrodes of the first TFT serve as source/drain electrodes of the second TFT). This integration eliminates the need for separate temperature sensing components, reducing device complexity while enabling dynamic temperature monitoring to maintain peak brightness without thermal damage.
Solution Approach 2:
The first thin film transistor serves dual functions: as a switching transistor for pixel operation and as a temperature sensing element. By utilizing the off-current characteristics of this transistor, the circuit achieves both pixel control and temperature monitoring capabilities, thereby improving display performance without adding dedicated temperature sensing components.
2Measurement precision
If additional sensing components or materials are added to the pixel circuit, then temperature measurement precision is improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The pixel circuit components serve dual purposes: the first thin film transistor functions as both a switching element for pixel operation and as a temperature sensor. The off-current characteristics of this existing transistor are utilized for temperature sensing, eliminating the need for additional sensing components or specialized materials, thereby maintaining measurement precision while reducing manufacturing cost and process complexity.
3Reliability
If a fixed current limit is set to prevent overheating, then reliability is improved, but peak brightness capability deteriorates
Solution Approach 1:
The temperature sensor circuit enables dynamic monitoring of pixel temperature through real-time measurement of off-current characteristics. This dynamic temperature information allows the display system to adjust operating parameters adaptively, preventing overheating while maintaining high peak brightness when thermal conditions permit, thereby resolving the contradiction between reliability and brightness capability.
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 real-time temperature monitoring, enhancing display performance by preventing overheating and reducing manufacturing costs through simplified processes, while maintaining high sensitivity and accuracy across a wide temperature range.
Implementation Method 1
the present disclosure relates to technology for monitoring temperature change inside a pixel of a high-brightness active matrix micro-LED display by using the off-current characteristics of thin film transistors constituting a temperature sensor circuit according to temperature change
Data Source
AI summary
The present disclosure relates to a temperature sensor circuit for measuring temperature change inside a pixel of a high-brightness active matrix micro-light-emitting diode (micro-LED) display, and a display apparatus including the temperature sensor circuit. The temperature sensor circuit according to one embodiment of the present disclosure includes a first thin film transistor, a second thin film transistor interconnected with the first thin film transistor, and a temperature measurement unit for measuring temperature based on an output voltage according to difference in off current between the first thin film transistor and the second thin film transistor.