Vertically Overlapping Image Sensor Pixels for Multi-Wavelength Detection
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Solution Overview
Problem
Current image sensors lack the ability to efficiently integrate multiple functions into a single device, leading to increased size and reduced sensitivity within a unit area, as they are designed for specific wavelengths and functionalities, limiting their versatility and performance in various applications.
Innovation Solution
The integration of multiple sensor pixels with different signal generation circuits and photoelectric converters on a single substrate, where each pixel is optimized for specific wavelengths, allowing for the simultaneous detection of different types of information, such as depth and iris recognition, within a compact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple separate image sensors are used for different functions, then each sensor can be optimized for its specific function, but the overall device size increases and sensitivity per unit area decreases
Solution Approach 1:
The patent combines multiple image sensors with different functions (e.g., visible light sensor, near-infrared sensor, depth sensor) into a single integrated sensor module. This merging approach allows the device to maintain functional optimization for each sensor type while reducing the overall device size and increasing sensitivity per unit area, directly resolving the technical contradiction between functional specialization and compact integration.
Solution Approach 2:
The integrated sensor module is designed to perform multiple functions simultaneously through a universal platform that accommodates different sensor types. Each sensor within the module maintains its specialized functionality while the overall module achieves multi-functionality, allowing the system to capture various types of information (visible light, infrared, depth) without requiring separate dedicated devices.
2Reliability
If multiple separate image sensors are used for different functions, then each sensor can be optimized for its specific function, but the sensitivity within a unit area is reduced
Solution Approach 1:
By merging multiple sensors into a single integrated module with shared support structures and circuitry, the patent achieves higher sensitivity per unit area. The compact integration allows more sensor elements to be packed into a smaller area, increasing the density of photoelectric converters and improving overall sensitivity while maintaining the functional optimization of each sensor type.
Solution Approach 2:
The patent employs a nested structure where multiple sensor layers are stacked vertically or arranged in overlapping configurations. This nesting approach allows sensors to be positioned in three-dimensional space, maximizing the use of available area and improving sensitivity per unit area while maintaining functional optimization for each sensor layer.
3Measurement precision
If a single image sensor is designed for a specific wavelength, then it can achieve high sensitivity for that wavelength, but it cannot detect other wavelengths or perform multiple functions
Solution Approach 1:
The integrated sensor module is designed as a universal platform that incorporates multiple sensors capable of detecting different wavelengths (visible light, near-infrared, etc.). Each sensor within the module maintains its wavelength-specific sensitivity through specialized photoelectric converters, while the overall module achieves multi-functionality by simultaneously performing multiple detection tasks across different spectral ranges.
Solution Approach 2:
Different regions of the sensor module are optimized for specific wavelength ranges through localized photoelectric converter designs. Each sensor area has tailored properties (e.g., bandgap energy, absorption characteristics) matched to its intended wavelength range, allowing high wavelength-specific sensitivity while the entire module provides versatile multi-wavelength detection capabilities.
4Measurement precision
If multiple sensor functions are integrated into one image sensor, then sensitivity within a unit area is improved, but the device complexity increases
Solution Approach 1:
The patent uses a nested architectural approach where multiple sensor layers and support structures are organized in a hierarchical manner. This nesting reduces integration complexity by providing a systematic framework for combining multiple functions, allowing sensors to be stacked or arranged in predefined configurations with shared infrastructure, thereby improving sensitivity per unit area without proportionally increasing complexity.
Solution Approach 2:
The integrated sensor module is divided into distinct functional segments or layers, each responsible for specific detection tasks. This segmentation allows independent optimization and testing of each component, reducing overall integration complexity while maintaining high sensitivity through the coordinated operation of multiple specialized segments within a unified module.
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 sensitivity and functionality of image sensors by allowing them to capture multiple types of information within a smaller area, improving their integration and reducing waste space, thereby enabling more efficient use of pixel space and enhanced performance in multi-functional applications.
Implementation Method 1
a first photoelectric converter connected to the first signal generation circuit and configured to generate first information from a first signal obtained from light having a first wavelength
Implementation Method 2
a second photoelectric converter connected to the second signal generation circuit and vertically overlapping the first photoelectric converter and configured to generate second information different from the first information from a second signal obtained from light having a second wavelength
Implementation Method 3
a dual band pass filter configured to selectively pass light having a first wavelength and light having a second wavelength selected from a near-infrared range among light reflected from the target object
Implementation Method 4
the second photodiode is configured to absorb a selected light from among the light having a first wavelength and the light having a second wavelength and pass an unselected light from among the light having a first wavelength and the light having a second wavelength
Data Source
AI summary
An image sensor includes a first sensor pixel and a second sensor pixel that vertically overlap each other. The first sensor pixel includes a first signal generation circuit, and a first photoelectric converter that is connected to the first signal generation circuit and configured to generate first information from light having a first wavelength. The second sensor pixel includes a second signal generation circuit, and a second photoelectric converter that is connected to the second signal generation circuit and configured to generate second information from light having a second wavelength. A first horizontal surface area of the first photoelectric converter is different from a second horizontal surface area of the second photoelectric converter. An image sensor module includes the image sensor, a light source configured to emit light to a target object, and a dual band pass filter configured to selectively pass light reflected from the target object.