Solid-State Imaging Device Temperature Control
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Solution Overview
Problem
Image sensors using materials with lower band gap energy than silicon, such as InGaAs, exhibit higher sensitivity to temperature variations, leading to increased dark current and degraded image quality as temperature increases, necessitating effective temperature control mechanisms.
Innovation Solution
A solid-state imaging device with a photoelectric conversion unit using a material with lower band gap energy than silicon, coupled with a circuit substrate incorporating a thermometer circuit and temperature control signal generation circuit to monitor and control temperature, utilizing a Peltier element for temperature regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a photoelectric conversion film using material with lower band gap energy than silicon (such as InGaAs) is used, then sensitivity to long wavelength light (infrared light) is improved, but dark current increases with temperature and image quality degrades
Solution Approach 1:
The patent applies parameter changes by implementing active temperature control through a Peltier element to maintain the photoelectric conversion unit at a constant optimal temperature. This compensates for the inherent temperature sensitivity of low band gap materials, preventing dark current increase while preserving infrared sensitivity. The thermometer circuit continuously monitors temperature to enable dynamic adjustment of cooling power.
2Reliability
If temperature control circuits are integrated into the circuit substrate, then temperature control capability is improved, but device complexity increases
Solution Approach 1:
The patent merges the thermometer circuit and temperature control signal generation circuit directly into the circuit substrate that processes pixel signals. This integration consolidates multiple functions (signal processing, temperature sensing, and control) onto a single substrate, reducing the need for separate components and interconnections. The merged design simplifies the overall device architecture while maintaining reliable temperature control capability.
3Adaptability or versatility
If multiple circuits are integrated on the circuit substrate, then functionality is improved, but manufacturing precision requirements increase
Solution Approach 1:
The circuit substrate is designed with multi-functionality, serving simultaneously as the pixel signal processing platform and the temperature control system base. The thermometer circuit and temperature control signal generation circuit share the same substrate infrastructure (power supply, signal lines, mounting structures) with the pixel processing circuits. This universal design reduces manufacturing precision requirements by reusing existing fabrication processes and structural elements across multiple functions.
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
Accurately measures and controls the temperature of the image sensor, reducing dark current noise and maintaining image quality by integrating the thermometer circuit and Peltier element within the device, enhancing robustness and yield while minimizing terminal count.
Implementation Method 1
utilizing a Peltier element for temperature regulation
Implementation Method 2
a photoelectric conversion unit that is configured by using a material with lower band gap energy than silicon
Data Source
AI summary
The present disclosure relates to a solid-state imaging device, a package, and an imaging system capable of curbing degradation of image quality.A solid-state imaging device according to an aspect of the present technology includes: a photoelectric conversion unit that is configured by using a material with lower band gap energy than silicon; and a circuit substrate that is joined to the photoelectric conversion unit, in which the circuit substrate includes a pixel signal generation circuit that generates a pixel signal of a voltage value in accordance with a charge generated by the photoelectric conversion unit, a thermometer circuit that detects a temperature of the circuit substrate, and a temperature control signal generation circuit that acquires temperature information indicating the temperature detected by the thermometer circuit and generates a temperature control signal on the basis of the acquired temperature information.