Infrared Imaging Device Voltage Drop Compensation
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Solution Overview
Problem
In thermal infrared solid-state imaging devices, the voltage drop in drive lines leads to offset distribution and temperature drift, which complicates the detection of infrared signals, especially as the number of pixels increases, making it difficult to maintain frame rate and precision.
Innovation Solution
The device incorporates a differential integrating circuit and a bias line with a voltage drop similar to the drive line, along with a reference signal output circuit using dummy pixels without thermally insulating or infrared-absorbing structures, to correct voltage drops and temperature drift by generating a bias voltage that compensates for these issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels is increased to achieve mega-pixel structure, then the imaging resolution is improved, but the voltage drop in drive lines increases causing offset distribution and temperature drift
Solution Approach 1:
The pixel array is divided into multiple blocks, with each block independently driven by its own drive line. This segmentation reduces the length of individual drive lines, thereby minimizing voltage drop and offset distribution while maintaining high-resolution mega-pixel structure
Solution Approach 2:
Dummy pixels are introduced as intermediary elements to measure and compensate for voltage drops and temperature drifts in drive lines. These dummy pixels serve as reference points that enable real-time correction of voltage instability without affecting the actual imaging pixels
2Measurement precision
If the thermally insulating structure is added to pixels to improve infrared detection, then the infrared signal detection is improved, but the device temperature drift affects measurement precision
Solution Approach 1:
Dummy pixels without thermally insulating structures are used as intermediaries to measure device temperature drift. By comparing the output of dummy pixels (which experience only temperature drift) with actual pixels, the system can separate and compensate for temperature effects from infrared signal effects
Solution Approach 2:
The system dynamically adjusts the bias voltage applied to pixels based on temperature measurements from dummy pixels. By changing the bias voltage parameter in response to temperature drift, the system maintains measurement precision despite temperature variations
3Measurement precision
If the amplifier gain is increased to amplify the small infrared response signal, then the signal detection sensitivity is improved, but the amplifier becomes saturated by voltage drop distribution
Solution Approach 1:
The system performs preliminary measurement of voltage drops using dummy pixels before amplification. By measuring the offset voltage in advance and subtracting it from the pixel output, the system eliminates the harmful voltage drop component before it can cause amplifier saturation, enabling safe amplification of the infrared signal
Solution Approach 2:
The harmful voltage drop component is extracted and separated from the pixel output signal through differential measurement with dummy pixels. By taking out this unwanted offset component, the system allows the amplifier to work only with the useful infrared signal, preventing saturation
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 configuration reduces voltage drop in the drive line and suppresses temperature drift, allowing for stable and precise infrared signal detection even in mega-pixel structures, while maintaining or improving frame rate and reducing the operating speed of the horizontal scanning circuit.
Implementation Method 1
a diode having one or more infrared ray absorbing structures 1106
Implementation Method 2
thermal infrared solid-state imaging device for detecting a temperature change generated by an incident infrared ray
Implementation Method 3
The diode includes a thermally insulating structure and/or an infrared ray absorbing structure
Data Source
AI summary
A thermal infrared solid-state imaging device includes a horizontal scanning circuit for scanning a pixel area horizontally to read an infrared image, and vertical scanning circuits provided at both ends of the pixel area. The vertical scanning circuits drive a drive line by applying a driving voltage at both ends of the drive line (in two-end driving). Further a bias voltage is applied at the end of the pixel area to a bias line connected to differential integrating circuits.