Stacked Image Sensor Layout for Visible and Infrared Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image sensors that simultaneously detect visible and infrared light face challenges in maintaining resolution and separating drive circuits due to differences in pixel size and voltage requirements, particularly when using vertically stacked structures with avalanche multiplication light-emitting diodes.
Innovation Solution
An image sensor design featuring a light receiving unit with a long wavelength sensor array and a short wavelength sensor array separated by an insulator layer, where the insulator reflects short wavelength light and allows long wavelength light to transmit, along with an optical filter to further separate wavelength bands, enabling efficient drive circuit separation and reduced mixed color.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If vertically stacked structure with APD is used to simultaneously detect visible and infrared light, then both wavelength bands can be detected, but high voltage must be applied to the APD creating mixed drive voltage regions which complicates circuit design
Solution Approach 1:
The sensor is divided into two separate sensor arrays: a first sensor array for visible light detection and a second sensor array for infrared light detection. Each array has its own dedicated drive circuit, eliminating the need for mixed high-voltage and low-voltage drive regions in a single array. This segmentation allows each circuit to be optimized for its specific voltage requirements without design complications.
2Adaptability or versatility
If vertically stacked structure is used to simultaneously detect visible and infrared light, then both wavelength bands can be detected, but pixel size differs between visible light pixel and infrared light pixel making structure design difficult
Solution Approach 1:
The sensor array is segmented into two independent arrays with different pixel sizes optimized for their respective wavelength bands. The first sensor array uses pixel size optimized for visible light while the second sensor array uses pixel size optimized for infrared light. This segmentation allows each array to have its own optimal pixel dimensions without compromising the other.
Solution Approach 2:
The patent transitions from a single-plane horizontal array to a vertically stacked multi-layer structure. The first and second sensor arrays are arranged in different vertical layers, allowing each array to maintain its optimal pixel size independently while still achieving simultaneous detection of both wavelength bands through the stacked configuration.
3Adaptability or versatility
If horizontal array structure with replaced Bayer pixels is used, then infrared light can be detected, but resolution is degraded due to replacement of visible light pixels
Solution Approach 1:
Instead of replacing pixels in a single horizontal plane, the patent stacks sensor arrays in the vertical dimension. The first sensor array for visible light and the second sensor array for infrared light are positioned in different vertical layers, allowing both arrays to maintain their full pixel counts and resolution without sacrificing visible light pixels for infrared detection.
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 design reduces resolution degradation and mixed color issues while allowing for improved separation of drive circuits, enabling accurate simultaneous detection of visible and infrared light without the need for high voltage application.
Implementation Method 1
an insulator layer that is positioned on the long wavelength sensor array, and reflects light of a short wavelength side among the light of the predetermined wavelength band, and allows the light of the long wavelength side to transmit through the insulator layer
Implementation Method 2
a first substrate including a first set of photoelectric conversion units; a second substrate including a second set of photoelectric conversion units
Data Source
AI summary
There is provided an imaging device, an electronic apparatus including an imaging device, and an automotive vehicle including an electronic apparatus including an imaging device, including: a first substrate including a first set of photoelectric conversion units; a second substrate including a second set of photoelectric conversion units; and an insulating layer between the first substrate and the second substrate; where the insulating layer has a capability to reflect a first wavelength range of light and transmit a second wavelength range of light that is longer than the first wavelength range of light.