Stacked 2D and Depth Sensor Alignment Through Optical Interconnects
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Solution Overview
Problem
Existing image acquisition devices face challenges in simultaneously acquiring high-quality 2D visible images and depth images due to misalignment issues and increased size and cost associated with using separate sensors, as well as integration complexities caused by differing pixel dimensions and supply voltages.
Innovation Solution
A device comprising a first sensor with 2D image pixels and an interconnect stack on a semiconductor substrate, alongside a second sensor with depth pixels on a separate substrate, where the depth pixels are positioned opposite regions within the interconnect stack, utilizing materials with specific optical properties to enhance alignment and reduce size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separate image sensors are used to capture 2D image and depth image, then both images can be acquired simultaneously, but misalignment between pixels of corresponding images occurs and device size and cost increase
Solution Approach 1:
The patent combines 2D image pixels and depth pixels into a single integrated sensor array where both types of pixels share the same physical substrate and optical path. This merging eliminates the misalignment issue between separate sensors while maintaining the ability to simultaneously capture both 2D and depth information from the same viewpoint.
Solution Approach 2:
The patent introduces a vertical stacking dimension by placing 2D image pixels and depth pixels at different depths within the same sensor array. The depth pixels are positioned beneath the 2D pixels, allowing both sensor types to coexist in the same spatial footprint while capturing information from identical optical paths.
2Productivity
If separate image sensors are used to capture 2D image and depth image, then both images can be acquired simultaneously, but device size and cost increase
Solution Approach 1:
The patent merges 2D image pixels and depth pixels into a single integrated sensor array, allowing both sensor types to share the same physical substrate and optical path. This consolidation reduces the overall device area compared to using separate sensors, while maintaining simultaneous acquisition capability.
Solution Approach 2:
The patent implements a nested structure where depth pixels are positioned beneath 2D image pixels within the same sensor array. This nested arrangement allows depth sensing functionality to be embedded within the 2D imaging structure, maximizing space utilization and minimizing device footprint.
3Measurement precision
If 2D image pixels and depth pixels are integrated in the same detector array, then alignment is improved and device size is reduced, but integration becomes complex due to different pixel dimensions and supply voltages
Solution Approach 1:
The patent applies local quality by providing different supply voltages to different regions of the sensor array. Specifically, 2D image pixels receive one voltage level while depth pixels receive another, allowing each pixel type to operate at its optimal voltage without interfering with the other. This regional differentiation simplifies the integration process despite the different requirements.
Solution Approach 2:
The patent segments the sensor array into distinct regions for 2D image pixels and depth pixels, with separate readout circuits and control logic for each type. This segmentation allows independent optimization and simplification of each subsystem while maintaining their integrated structure, reducing overall integration complexity.
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
The solution enables simultaneous acquisition of high-quality 2D and depth images with improved alignment and reduced device size and cost, while maintaining high resolution and efficiency.
Implementation Method 1
each region comprises a first portion extending into the interconnect stack from a first face of the interconnect stack facing the first substrate and a second portion extending from a second face of the interconnect stack facing the second substrate... the material of the regions having, over a working wavelength range of the second sensor, an optical index greater than or equal to that of the substrate material
Data Source
AI summary
A device for acquiring a 2D image and a depth image, including: a first sensor formed in and on a first semiconductor substrate and including regions of a material distinct from that of the substrate located in an interconnect stack in line with 2D image pixels of the first r sensor; and adjoining the first sensor, a second sensor formed in and on a second semiconductor substrate and including a plurality of depth pixels located opposite the regions of the first sensor, wherein each region includes a first portion having, in top view, a smaller surface area than that of a second portion, the material of the regions having an optical index greater than or equal to that of the material of the substrate.