Double-Lens Structure for Solid-State Image Sensor Light Condensing
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Solution Overview
Problem
Solid-state imaging sensors suffer from reduced sensitivity due to lost light, as a significant amount of incident radiation is not directed onto the photo-sensors, limiting their efficiency.
Innovation Solution
A double-lens structure is introduced as a microlens array over the solid-state image sensor, comprising a color filter layer with a first refractive index and a micro-lens material layer with a second refractive index, designed to enhance light condensing efficiency by forming specific convex or concave profile surfaces, depending on the refractive index difference, to accurately focus incident light onto photoelectric conversion elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single microlens structure is used, then the device complexity is low, but the light condensing efficiency is insufficient causing light loss
Solution Approach 1:
The microlens array is segmented into two distinct lens structures: a first microlens formed from the color filter layer and a second microlens formed from the micro-lens material layer. This segmentation allows each lens to be optimized for specific optical functions, improving overall light condensing efficiency while managing complexity through modular fabrication processes
Solution Approach 2:
The double-lens structure employs composite materials with different refractive indices: the color filter layer material and the micro-lens material layer material. This composite approach enables superior optical performance by combining materials with complementary properties, achieving enhanced light condensing efficiency that cannot be obtained with a single material
2Productivity
If a double-lens structure is introduced, then the condensing efficiency is improved, but the manufacturing process complexity increases
Solution Approach 1:
The color filter layer is formed first and patterned into the first microlens structure before the micro-lens material layer is deposited and patterned into the second microlens structure. This preliminary action sequence allows each lens structure to be independently optimized and fabricated using standard photolithography and etching processes, making the complex double-lens structure manufacturable
Solution Approach 2:
The first microlens structure formed from the color filter layer serves as a substrate for the second microlens structure formed from the micro-lens material layer. This nesting arrangement allows the double-lens structure to be built incrementally, with each layer being fabricated and then serving as the base for the next layer, simplifying the overall manufacturing process
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 double-lens structure significantly improves the condensing efficiency of the microlens array, thereby enhancing the sensitivity of solid-state image sensors compared to single-lens structures, effectively addressing the issue of lost light and improving image capture capabilities.
Implementation Method 1
A double-lens structure is disposed over a solid-state image sensor and used as a microlens array for the solid-state image sensor. The double-lens structure includes a first lens structure formed of a color filter layer having a first refractive index and a second lens structure formed of a micro-lens material layer having a second refractive index. An incident light enters the second lens structure and then passes through the first lens structure.
Data Source
AI summary
A double-lens structure and a method for fabricating the same are provided. The double-lens structure includes a first lens structure formed of a color filter layer having a first refractive index and a second lens structure formed of a micro-lens material layer having a second refractive index and disposed on the first lens structure. The first refractive index of the color filter layer is different from the second refractive index of the micro-lens material layer. An incident light enters the second lens structure and then passes through the first lens structure. Further, a method for fabricating the double-lens structure is also provided.