Thermoelectric Pixel for Thermal Reset in CMOS Image Sensors

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Solution Overview

Problem

Conventional CMOS image sensors face challenges in efficiently performing thermal and electrical reset operations, particularly in adapting to temperature changes, which affects their performance and reliability.

Innovation Solution

The integration of a thermoelectric element with a Peltier-junction, comprising an n-type and p-type semiconductor element, allows for thermoelectric cooling and photoelectric conversion, enabling concurrent thermal and electrical reset operations by supplying distinct voltages to these elements during reset and photoelectric conversion processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional CMOS image sensors are used without integrated thermoelectric elements, then the device structure remains simple and manufacturing is easier, but the ability to perform thermal reset and adapt to temperature changes is insufficient

Engineering Contradiction:

Improvetemperature adaptation capabilityVSAvoidpixel structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the thermoelectric cooling function with the photoelectric conversion function by integrating a thermoelectric element (comprising n-type and p-type semiconductor elements) directly into the pixel structure. This allows the same pixel structure to perform both thermal reset through Peltier effect and photoelectric conversion, thereby improving temperature adaptation capability without proportionally increasing device complexity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The thermoelectric element integrated in the pixel serves multiple functions: it performs thermal reset through thermoelectric cooling during the reset period, and performs photoelectric conversion during the integration period. This multi-functionality allows a single component to address both temperature adaptation and image sensing requirements, improving versatility while managing structural complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of operation

If separate voltage supply paths are used for reset and photoelectric conversion operations, then operational control is improved, but circuit complexity increases

Engineering Contradiction:

Improveoperational control precisionVSAvoidvoltage supply circuit complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The voltage supply circuit is segmented into distinct paths: a first voltage supply path provides a first voltage to the n-type semiconductor element during reset operation, while a second voltage supply path provides an operation voltage to the p-type semiconductor element during photoelectric conversion. This segmentation enables precise operational control by independently managing voltages for different operational modes, while the modular path structure helps manage circuit complexity through organized functionality

Inventive Principle:

Principle #1Segmentation

3Reliability

If thermoelectric cooling is performed during reset operation, then thermal reset efficiency is improved, but energy consumption increases

Engineering Contradiction:

Improvethermal reset efficiencyVSAvoidpower consumption during reset

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The thermoelectric cooling is performed periodically during the reset period rather than continuously. The first voltage is supplied to the n-type semiconductor element specifically during the reset period to perform thermal reset, and then the operation switches to photoelectric conversion during the integration period. This periodic activation of the cooling function improves thermal reset efficiency while managing energy consumption by limiting cooling operation to only when necessary

Inventive Principle:

Principle #19Periodic action

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 approach enhances the CMOS image sensor's ability to adapt to temperature changes, improving reset efficiency and overall performance by allowing simultaneous thermoelectric and electrical reset operations, thereby improving image sensing capabilities.

Implementation Method 1

The Peltier-cooling may include Peltier-cooling the pixel using a Peltier-element having a Peltier-junction

Methodology Applied

Scientific EffectPeltier effect: Peltier Effect

Implementation Method 2

performing a photo-electric conversion operation using the thermoelectric element

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS9294702B2Image sensors for performing thermal reset, methods thereof, and devices including the same

Publication Date: 2016.03.22 SAMSUNG ELECTRONICS CO LTD

AI summary

A method of operating an image sensor includes: thermoelectrically cooling a pixel using a thermoelectric element having a thermoelectric-junction integrated to the pixel; and performing a photoelectric conversion operation using the thermoelectric element. An image sensor includes a pixel and a readout circuit. The pixel includes a thermoelectric element having a thermoelectric-junction, and the readout circuit is configured to control the pixel such that the thermoelectric element performs a thermoelectric-cooling operation and a photoelectric conversion operation.