Metal Mesh Light Pipe for Stacked Image Sensor Spectral Response
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image sensors, such as FSI and BSI sensors, have limited spectral responses, with BSI sensors performing better for visible light but poorly for near-infrared (NIR) or infrared (IR) light due to their thinner structure, while FSI sensors are better at detecting IR but at the expense of visible light performance.
Innovation Solution
A stacked image sensor configuration with a metal mesh light pipe is introduced, where a first sensor portion functions like an FSI to detect IR/NIR light and a second sensor portion functions like a BSI to detect visible light, using optical filters and aligned photodetectors to enhance light capture from the same source, and a combined metal-interconnect layer forms a light pipe to guide light between the sensor portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single sensor structure is used, then device complexity is reduced, but spectral response capability deteriorates
Solution Approach 1:
The image sensor is divided into two separate sensor portions: a first sensor portion optimized for detecting near-infrared and infrared light, and a second sensor portion optimized for detecting visible light. Each sensor portion has its own photodetectors and metal-interconnect layers configured for its specific wavelength range, allowing both detection functions to operate at optimal performance simultaneously.
Solution Approach 2:
The patent transitions from a single-layer sensor architecture to a stacked three-dimensional architecture where sensor portions are arranged in vertical layers. This enables light to be detected at different depths and wavelengths simultaneously, with the first sensor portion detecting longer wavelengths (NIR/IR) and the second sensor portion detecting shorter wavelengths (visible), effectively adding a spectral dimension to the detection capability.
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 enables superior detection of both visible and NIR/IR light, improving image quality by capturing more light without noise, especially in low-light conditions, and allows for the generation of digital images with better representation of both day and night vision.
Implementation Method 1
a combined metal-interconnect layer forms a light pipe to guide light between the sensor portions
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
Various embodiments are directed to a light pipe. The light pipe may include a channel within a substrate of an image sensor. The channel may be formed by a plurality of layers. The plurality of layers may include a first layer and a second layer. The second layer may be spaced apart from the first layer along an axis of the channel.