Solid State Imaging Device Pixel Segmentation
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Solution Overview
Problem
Uncooled infrared solid state imaging devices face challenges in reducing noise equivalent temperature difference (NETD), which affects their sensitivity and ability to accurately detect temperature information, especially in environments with noise sources.
Innovation Solution
The implementation of a solid state imaging device configuration that includes infrared detection pixels and non-sensitive pixels, along with a differential amplifier, where the non-sensitive pixels have a recess structure to minimize heat transfer, allowing for improved temperature resolution by enhancing the sensitivity of the thermoelectric conversion units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If uncooled infrared solid state imaging device uses thermoelectric conversion means to convert temperature change into electric signal, then the device can detect infrared light without cooling mechanism, but the noise equivalent temperature difference (NETD) increases reducing detection sensitivity
Solution Approach 1:
The imaging device is segmented into multiple independent pixel units, each with its own thermoelectric conversion means (p-n junction). This segmentation allows each pixel to independently convert temperature changes into voltage signals, enabling the device to achieve good temperature resolution without requiring a complex cooling mechanism. The segmentation of the pixel array into many small independent detection elements is key to resolving the contradiction between uncooled operation and measurement precision.
2Area of stationary object
If a large number of infrared detection pixels are arranged in matrix configuration and connected to common interconnection, then the device can image entire scenes, but the circuit complexity increases
Solution Approach 1:
Multiple pixels in the matrix configuration share common interconnections (row and column lines) to reduce the total number of connections. The p-n junctions serve dual purposes: as detection elements and as row selection switches. This merging of functions and sharing of interconnections significantly reduces circuit complexity while maintaining the ability to image entire scenes through the matrix array.
Solution Approach 2:
The p-n junction structure is designed to perform multiple functions: it acts as both the thermoelectric conversion element for detecting temperature changes and as the row selection switch for addressing specific pixels. This multi-functionality reduces the need for separate components, thereby simplifying the overall circuit configuration while maintaining full matrix imaging capability.
3Device complexity
If p-n junction is used as thermoelectric conversion means to utilize rectifying properties for row selection, then the pixel configuration can be simplified, but the temperature resolution and detection sensitivity are affected
Solution Approach 1:
The operating parameters of the p-n junction are optimized to balance its dual functions. By carefully controlling the forward current through each pixel and adjusting the bias conditions, the device achieves adequate temperature resolution while maintaining the simplicity of the p-n junction-based pixel configuration. The parameter optimization allows the same simple structure to serve both as detector and selector.
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 improves the detection sensitivity and reduces noise, enabling more accurate temperature measurement and imaging, particularly in noisy environments, while maintaining a simplified circuit configuration and downsized device.
Implementation Method 1
converts incident infrared light with wavelengths around 10 μm into heat using an absorption structure, then uses some kind of thermoelectric conversion means to convert the temperature change of a thermo-sensitive unit caused by this weak heat into an electric signal
Implementation Method 2
converts incident infrared light with wavelengths around 10 μm into heat using an absorption structure
Implementation Method 3
there is a solid state imaging device using a p-n junction of silicon in which a constant forward current is given to convert a temperature change into a voltage change
Data Source
AI summary
According to one embodiment, a solid state imaging device includes an infrared detection pixel configured to change an output potential by receiving infrared light, a non-sensitive pixel, a row select line, and a differential amplifier. An amount of change in an output potential when the non-sensitive pixel receives infrared light is smaller than an amount of change in an output potential when the infrared detection pixel receives the infrared light. The row select line is configured to apply a drive potential to both the infrared detection pixel and the non-sensitive pixel. The differential amplifier includes one input terminal to which an output potential of the infrared detection pixel is inputted and another input terminal to which an output potential of the non-sensitive pixel is inputted.