Vertical Color Sensor Stacking to Reduce Spectral Overlap
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Solution Overview
Problem
Conventional color sensors, such as Bayer and Foveon sensors, face challenges in miniaturization due to the need for multiple detectors and significant spectral overlaps in photoresponse, leading to reduced accuracy in color recognition.
Innovation Solution
A vertical color sensing element is developed using van der Waal semiconductors (vdW-Ss) with layered sensing materials like CIS, InSe, and GaS, stacked vertically to sense red, green, and blue light, respectively, with transparent insulating layers to avoid spectral overlaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional color sensors use multiple detectors arranged in lateral arrays (Bayer or Foveon structures), then color detection capability is achieved, but device volume increases and miniaturization becomes difficult
Solution Approach 1:
The patent transitions from lateral arrangement of detectors to vertical stacking of sensing layers. Multiple color sensing channels (R, G, B) are arranged in the vertical dimension rather than lateral space, enabling compact device volume while maintaining color detection capability through wavelength-dependent absorption characteristics of different semiconductor materials
Solution Approach 2:
The device segments the color sensing function into distinct vertical layers, each dedicated to detecting a specific color wavelength range. The R-sensing channel layer, G-sensing channel layer, and B-sensing channel layer are separated by transparent insulating layers, allowing independent optimization of each channel's sensitivity while maintaining compact overall structure
2Measurement precision
If conventional sensors use multiple detectors with significant spectral overlaps, then color sensing is enabled, but measurement accuracy deteriorates due to spectral confusion
Solution Approach 1:
Each sensing layer is designed with specific local optical properties - the R-sensing channel layer has high absorption for red light, the G-sensing channel layer for green light, and the B-sensing channel layer for blue light. This local optimization of spectral response characteristics minimizes spectral overlap and confusion while maintaining simple device structure
Solution Approach 2:
Transparent insulating layers are introduced as intermediary elements between adjacent sensing channels. These layers provide optical isolation to reduce crosstalk while maintaining electrical connectivity, thereby improving color sensing accuracy without significantly increasing device 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 achieves high accuracy in color sensing with a compact device volume, enabling scalable integration for miniature image capture devices and cameras suitable for micro-robotics applications.
Implementation Method 1
a R-sensing channel layer comprising a first sensing material... a G-sensing channel layer comprising a second sensing material... a B-sensing channel layer comprising a third sensing material
Implementation Method 2
a first transparent insulating layer disposed on a side of the R-sensing channel layer... a second transparent insulating layer disposed on a side of the G-sensing channel layer
Implementation Method 3
The first and second thicknesses can be based upon focal lengths of R-light, G-light and B-light entering the vertical color sensing device
Data Source
AI summary
Various examples are provided related to color and optical sensing with vertically stacked sensors. In one example, a vertical color sensing element includes a R-sensing channel layer including a first sensing material, G-sensing channel layer including a second sensing material, and a B-sensing channel layer including a third sensing material. First and second transparent insulating layer having first and second thicknesses are between the R and G sensing channel layers and the G and B sensing channel layers, respectively. The first and second thicknesses can be based upon focal lengths of R-light, G-light and B-light entering the vertical color sensing device. In another example, a vertical optical sensor can include a first sensing channel layer including a first sensing material, a transparent insulating layer, and a second sensing channel layer including a second sensing material. The first sensing material can be vdW-S and the second sensing material can be different.