Image Sensor Temperature Compensation Circuit
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Solution Overview
Problem
Image sensors, particularly complementary metal-oxide-semiconductor (CIS) image sensors, face challenges in reducing thermal noise and maintaining image quality as temperature increases, which current noise reduction methods, such as image signal processors, are insufficient to address effectively.
Innovation Solution
Incorporating a temperature sensor to sense the temperature of the image sensor and adjust the voltage level of control signals, allowing the pixel drive circuit to operate in different voltage levels based on the sensed temperature, thereby reducing thermal noise impact on image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the image sensor operates at higher temperature to improve performance, then processing speed and sensitivity are enhanced, but thermal noise increases causing deterioration of image quality
Solution Approach 1:
The patent implements dynamic adjustment of control signal voltage levels based on real-time temperature sensing. The pixel drive circuit switches between different voltage levels (first voltage level at higher temperature, second voltage level at lower temperature) to adapt to temperature changes, thereby maintaining optimal performance while minimizing thermal noise impact.
Solution Approach 2:
The patent changes the voltage level parameter of control signals in response to temperature variations. By sensing temperature and selecting appropriate voltage levels from multiple available levels, the system adjusts electrical parameters to counteract thermal noise effects and maintain image quality across different operating temperatures.
2Object-affected harmful factors
If multiple voltage levels are implemented for control signals to reduce thermal noise, then image quality is improved, but device complexity increases
Solution Approach 1:
The pixel drive circuit is designed to handle multiple voltage levels using the same basic circuit structure. The circuit can operate with different voltage levels depending on temperature conditions, making it multi-functional without requiring separate dedicated circuits for each voltage level, thus limiting the increase in device complexity.
3Object-affected harmful factors
If temperature sensing and dynamic voltage adjustment are implemented, then image quality under varying temperature conditions is improved, but power consumption increases
Solution Approach 1:
The temperature sensing and voltage level adjustment operate periodically rather than continuously. The system senses temperature and adjusts voltage levels at appropriate intervals, reducing unnecessary power consumption while still maintaining image quality stability under varying temperature conditions.
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 effectively prevents deterioration of image quality due to thermal noise by adjusting voltage levels of control signals in response to temperature changes, especially in high-temperature and low-luminance conditions, enhancing noise characteristics and maintaining image quality.
Implementation Method 1
a temperature sensor configured to sense temperature from the image sensor
Data Source
AI summary
A method for driving an image sensor includes the steps of: sensing temperature from the image sensor; selecting a voltage level of a control signal in accordance with the sensed temperature; and detecting an image in response to the control signal having the selected voltage level. An image sensor comprises a temperature sensor configured to sense a temperature of the image sensor and a pixel array configured to detect an image in response to a control signal, wherein the control signal varies in voltage level as a function of the sensed temperature.