Non-circular Microlens Array for Solid-state Image Sensor Light Collection
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Solution Overview
Problem
Existing solid-state image sensors with rotation-symmetric microlenses arrayed equidistant from the central portion experience reduced light collection efficiency due to increased gaps between microlenses compared to circular microlenses.
Innovation Solution
A solid-state image sensor with a microlens array where microlenses are arranged in rows and columns, with first and second microlenses having non-circular bottom shapes, where the width of the second microlens in a specific direction is larger than the first microlens, improving light collection efficiency by optimizing microlens positioning on a virtual circle centered at the array's center.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If rotation-symmetric microlenses are arrayed equidistant from the central portion, then the microlenses have uniform shape and position, but the gaps between microlenses increase and light collection efficiency decreases
Solution Approach 1:
The patent applies asymmetry by changing the microlens shape from rotation-symmetric to non-circular (e.g., teardrop-shaped) with different widths in different directions. The microlens has a first width in a first direction and a second width in a second direction, where the widths are different. This asymmetric design allows the microlens to fit more efficiently in the array, reducing gaps between adjacent microlenses while maintaining uniform positioning, thereby improving light collection efficiency without sacrificing manufacturing precision
2Ease of manufacture
If circular microlenses are used, then the shape is simple and manufacturing is easier, but gaps between microlenses increase reducing light collection efficiency
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the microlens from a circular shape (equal widths in all directions) to a non-circular shape with different width parameters in different directions. Specifically, the microlens has a first width in a first direction and a second width in a second direction, where these width parameters are different. This parameter modification reduces the gaps between microlenses in the array, improving light collection efficiency while the overall simple geometric form maintains ease of manufacture
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
Enhances light collection efficiency by strategically positioning microlenses with non-circular shapes, reducing gaps and improving light ray collection to photoelectric converters, outperforming rotation-symmetric microlens arrangements.
Implementation Method 1
Each pixel includes a microlens
Implementation Method 2
photoelectric converter configured to convert incident light into an electrical signal
Data Source
AI summary
An image sensor includes microlens array having microlenses arranged to constitute rows and columns. When first axis parallel to the rows and passing through array center of the microlens array, and second axis parallel to the columns and passing through the array center are defined, microlens positioned on virtual circle having the array center as center includes first microlens positioned on the first or second axis, and second microlens positioned on neither the first axis nor the second axis. The first and second microlens have non-circular bottom shape, and width of the second microlens in second direction passing through the second microlens and the array center is larger than width of the first microlens in first direction passing through the first microlens and the array center.