Pixel Sensing Circuit With Light-Shielded Temperature Compensation
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Solution Overview
Problem
Current displays with fingerprint identification functions face accuracy issues due to environmental temperature affecting photo-sensing signals, as existing temperature-sensing components cannot be illuminated, preventing their use as photo-sensing components.
Innovation Solution
A sensing circuit incorporating a photo-sensing component, a transistor, and a temperature-sensing component with a channel structure, gates, and a light-shielding structure, allowing the semiconductor device to operate as either a temperature-sensing or switch component based on control signals, enabling separate photo-sensing and temperature-sensing functionalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature-sensing component is added to correct photo-sensing signals according to temperature, then the accuracy of fingerprint imaging is improved, but the device complexity increases and the photo-sensing component cannot be used for temperature sensing
Solution Approach 1:
The patent makes the photo-sensing component multi-functional by enabling it to perform both photo-sensing and temperature-sensing functions. The same photo-sensing component is used for both detecting light signals from fingerprint images and sensing temperature, eliminating the need for a separate temperature-sensing component and reducing device complexity while maintaining measurement precision
2Device complexity
If the photo-sensing component is used for temperature sensing, then the device complexity is reduced, but light interference affects the temperature sensing accuracy
Solution Approach 1:
The patent segments the operation into distinct time periods: a first time period for photo-sensing where light is detected, and a second time period for temperature-sensing where light is blocked. This temporal segmentation allows the same component to perform both functions without interference, as the component senses temperature during the period when no light is present
Solution Approach 2:
The patent implements periodic switching between photo-sensing mode and temperature-sensing mode. The control circuit periodically activates the photo-sensing component for light detection, then switches it to temperature-sensing mode, creating a rhythmic operation pattern that prevents light interference during temperature measurement while maintaining both functionalities
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
This solution effectively isolates temperature-sensing from light interference, allowing for accurate fingerprint imaging by adjusting photo-sensing signals based on environmental temperature, thereby enhancing the accuracy of fingerprint identification.
Implementation Method 1
The light-shielding structure is arranged above the first gate and is configured to shield the light coming from above the temperature-sensing component
Implementation Method 2
The photo-sensing component is configured to receive a light and transmit a first current according to an intensity of the light
Implementation Method 3
The channel structure is configured to transmit the second current
Data Source
AI summary
The present disclosure provides a sensing circuit, including a photo-sensing component, a first transistor, and a temperature-sensing component. The photo-sensing component is configured to receive a light and transmit a first current according to an intensity of the light. A gate terminal of the first transistor is configured to receive a first control circuit. The photo-sensing component and the first transistor are coupled in series between first and second nodes. The temperature-sensing component is coupled between the first and second nodes and is configured to generate a second current according to a temperature. The temperature-sensing component includes a channel structure, a first gate, a second gate, and a light-shielding structure. The channel structure is configured to transmit the second current.