Image Sensor Shielding Layer and Color Filter Structure for Light Absorption
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Solution Overview
Problem
Image sensors struggle to reduce external light reflection, making them visible and affecting their appearance and functionality, especially in applications like fingerprint sensing systems where a dark appearance is desired.
Innovation Solution
Incorporating a shielding layer and a color filter structure with multiple layers of different colors, where each layer defines openings of varying sizes, to absorb a wide range of wavelength bands and minimize external light reflection, while ensuring that only vertical components of incident light reach the photoelectric element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shielding layer and color filter structure are added to reduce light reflection, then the image sensor appears dark and light reflection is reduced, but the device complexity increases
Solution Approach 1:
The patent implements a nested structure where the color filter structure is positioned over the shielding layer, with multiple color filter layers (first, second, and third color filter layers) nested within each other. Each layer defines openings that are vertically aligned, creating a nested configuration that maximizes light absorption while maintaining a compact form factor. This nested arrangement allows the structure to appear dark from the front while keeping the overall device complexity manageable through systematic layering.
Solution Approach 2:
The patent addresses light reflection by transitioning from a two-dimensional surface treatment to a three-dimensional multi-layered structure. The shielding layer and color filter structure extend vertically above the photoelectric element, creating depth in the Z-dimension. This dimensional transition allows the structure to absorb light from multiple angles and wavelength bands, effectively reducing reflection while the vertical stacking maintains a space-efficient design.
2Loss of energy
If multiple color filter layers with different colors are used to absorb wide wavelength bands, then light absorption is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent divides the light absorption function into multiple segments by implementing separate color filter layers, each responsible for absorbing specific wavelength bands. The first color filter layer absorbs certain wavelengths, the second color filter layer absorbs different wavelengths, and the third color filter layer absorbs remaining wavelengths. This segmentation of the absorption function across multiple specialized layers improves overall light absorption efficiency while allowing each layer to be manufactured using standardized processes.
Solution Approach 2:
The patent employs composite material structures by combining multiple color filter layers with different optical properties. Each color filter layer is composed of materials designed to absorb specific wavelength ranges, and their combination creates a composite structure with broad-spectrum absorption capabilities. This composite approach enables efficient light absorption across wide wavelength bands while leveraging established manufacturing techniques for each individual layer.
3Loss of energy
If openings of varying sizes are defined in each color filter layer, then light absorption efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent implements local quality variations by defining openings of different sizes in different color filter layers. The first color filter layer has openings of a first size, the second color filter layer has openings of a second size, and the third color filter layer has openings of a third size. Each opening size is optimized for its specific layer's absorption function, creating local quality variations that enhance overall light absorption efficiency while allowing standardized manufacturing processes for each layer.
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 effectively makes the image sensor appear dark from the outside, reducing visible light reflection and enhancing its functionality by absorbing most incident light, thereby improving its performance in applications like fingerprint sensing.
Implementation Method 1
absorb a wide range of wavelength bands and minimize external light reflection
Implementation Method 2
The photodiode may convert incident light into an electrical signal
Data Source
AI summary
An electronic device may include a photoelectric element, a shielding layer on the photoelectric element, and a color filter structure on the shielding layer. The shielding layer may define a first opening over the photoelectric element. The color filter structure may define a second opening over the photoelectric element and the first opening. The color filter structure may appear dark from a view facing the color filter structure.