Stacked Image Sensor Wavelength Segmentation for Color Distortion
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Solution Overview
Problem
Image sensors with a stacking structure face distortion in color signals due to structural issues, leading to deteriorated color reproduction characteristics.
Innovation Solution
The image sensor incorporates a first light detecting device for shorter wavelengths, a second light detecting device for longer wavelengths, and a third light detecting device for wavelengths between, with specific maximum transmission and absorption wavelengths, integrated in a semiconductor substrate, and includes color filters and light-absorption layers to optimize light transmission and absorption characteristics for the stacking structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If an image sensor with a stacking structure is used to reduce size, then the image sensor size is reduced, but color signal distortion occurs and color reproduction characteristics deteriorate
Solution Approach 1:
The image sensor divides the light detection function into multiple stacked devices, each responsible for different wavelength regions. The first light detecting device handles blue light (shorter wavelengths), the second handles red light (longer wavelengths), and the third handles green light (intermediate wavelengths). This segmentation allows each device to be optimized for its specific wavelength range, reducing color signal distortion while maintaining compact size.
Solution Approach 2:
Each light detecting device in the stack is designed with specific local characteristics: the first device has optimized sensitivity for blue wavelengths, the second for red wavelengths, and the third for green wavelengths. This local quality optimization ensures that each component contributes effectively to its designated color channel, preventing cross-contamination and improving overall color reproduction accuracy in the stacked configuration.
2Volume of moving object
If multiple light detecting devices are stacked to reduce size, then the image sensor becomes more compact, but structural problems cause color signal distortion
Solution Approach 1:
The third light detecting device, positioned between the first and second devices in the stack, acts as an intermediary that selectively detects green light wavelengths. This intermediate device prevents direct interference between the blue-sensitive first device and the red-sensitive second device, thereby reducing color signal distortion caused by the stacking structure while maintaining the compact form factor.
3Manufacturing precision
If color filters with specific wavelength ranges are used in stacked devices, then color reproduction is improved, but the device complexity increases
Solution Approach 1:
Each light detecting device in the stack is designed to perform multiple functions: it serves as both a light detection element and a wavelength-selective filter for its designated region. The first device detects blue light and simultaneously blocks longer wavelengths, the second detects red light and blocks shorter wavelengths, and the third detects green light and blocks both shorter and longer wavelengths. This multi-functionality reduces the need for additional separate filtering components, thereby managing device complexity while improving color reproduction.
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 or prevents color signal distortion, enhancing color reproduction characteristics and enabling a compact, downsized image sensor design.
Implementation Method 1
a first color filter overlapping the first photo-sensing device and having a maximum transmission wavelength of less than about 440 nm
Implementation Method 2
a second color filter overlapping the second photo-sensing device and having a maximum transmission wavelength greater than about 630 nm
Implementation Method 3
a second light-absorption layer between the third electrode and the fourth electrode and configured to selectively absorb the first visible light and having a maximum absorption wavelength less than about 440 nm
Implementation Method 4
a third light-absorption layer between the fifth electrode and the sixth electrode and configured to selectively absorb the second visible light
Data Source
AI summary
An image sensor includes a first light detecting device configured to selectively sense or absorb first visible light, a second light detecting device configured to selectively sense or absorb second visible light having a longer wavelength region than the first visible light, and a third light detecting device on the first light detecting device and the second light detecting device. The first light detecting device has one of a maximum transmission wavelength and a maximum absorption wavelength less than about 440 nm, the second light detecting device has one of a maximum transmission wavelength and a maximum absorption wavelength greater than about 630 nm, and the third light detecting device is configured to selectively sense or absorb third visible light having a wavelength region between the first visible light and the second visible light.