Stacked Visible-SWIR Image Sensor Layout Without Resolution Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image sensor arrangements that aim to detect both visible and infrared light suffer from reduced spatial resolution and quantum efficiency due to the integration of NIR pixels, which affect color reconstruction and image perception.
Innovation Solution
The implementation of a dual-layer image sensor arrangement where one layer is spectral responsive to visible light and the other to short-wavelength infrared (SWIR) light, with SWIR pixels not affecting the visible light sensor, allowing for separate and efficient detection of both wavelength ranges without compromising image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional NIR pixels are arranged in the same silicon substrate by sacrificing subpixels, then the sensor can detect both visible and NIR light, but spatial resolution and image perception in the visible domain deteriorate
Solution Approach 1:
The patent transitions from a two-dimensional planar pixel arrangement to a three-dimensional stacked architecture with multiple sensor layers separated in the vertical dimension. This allows NIR and visible light pixels to coexist without spatial overlap, maintaining full spatial resolution in both wavelength domains while enabling dual-band detection capability.
Solution Approach 2:
The pixel array is segmented into separate sensor layers, with each layer dedicated to a specific wavelength range (NIR or visible). This segmentation eliminates the need to sacrifice subpixels within a single layer, as each layer operates independently with its own complete pixel array, preserving spatial resolution while achieving wavelength-specific detection.
2Adaptability or versatility
If a multi-storied photodiode structure with two substrates is used to capture visible and NIR light simultaneously, then both wavelength ranges can be detected, but quantum efficiency for NIR light deteriorates due to blocking and scattering effects
Solution Approach 1:
The patent extracts the NIR detection function into a separate dedicated sensor layer with specialized photodiodes optimized for NIR wavelengths. This extraction eliminates the blocking and scattering effects caused by visible light optical elements (lenses, filters, wiring) that are present in the multi-storied structure, thereby achieving high quantum efficiency for NIR detection while maintaining dual-band capability.
Solution Approach 2:
The patent introduces an intermediate optical structure (including transparent substrates and optimized light paths) between the NIR pixels and the incoming radiation. This intermediary minimizes blocking and scattering effects, allowing NIR light to reach the photodiodes with high transmission efficiency while still enabling integration with visible light detection components.
3Adaptability or versatility
If additional wiring layers and substrates are added to support dual-band detection, then both visible and NIR light can be detected, but device complexity increases
Solution Approach 1:
The patent implements a common readout circuit layer that serves both NIR and visible light pixels, enabling a single circuit structure to handle signals from multiple sensor layers. This universal readout approach reduces the need for separate dedicated circuits for each wavelength band, thereby reducing overall device complexity while maintaining full spectral responsiveness.
Solution Approach 2:
The patent merges the readout functions of NIR and visible light pixels into a shared readout circuit layer. By combining these functions, the patent reduces the total number of independent circuit blocks and interconnect layers required, simplifying the overall device architecture while preserving the ability to detect both wavelength ranges with high performance.
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 maintains high spatial resolution and quantum efficiency for both visible and SWIR light detection, eliminating the need for color correction and ensuring improved image perception without trade-offs in image quality.
Implementation Method 1
each pixel of the first group comprising a photodiode configured to detect electromagnetic radiation in a first wavelength range
Data Source
AI summary
An image sensor arrangement includes a first sensor layer having a first group of pixels. Each pixel of the first group includes a photodiode configured to detect electromagnetic radiation in a first wavelength range. The image sensor arrangement also includes a second sensor layer having a second group of pixels. Each pixel of the second group includes a photodiode configured to detect electromagnetic radiation in a second wavelength range. The image sensory arrangement further includes a readout layer having a readout circuit configured to read out electrical signals from the pixels of the first and the second group. The second sensor layer is arranged between the first sensor layer and the readout layer. The second wavelength range is outside a wavelength range detectable by the first sensor layer. The first sensor layer is attached to the second sensor layer by hybrid bonding.