Variable Curvature Microlens Array for Solid-State Imaging
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Solution Overview
Problem
Existing optical element arrays, such as microlens arrays, have a low area occupancy ratio and limited light collection ability due to their teardrop form design, which results in inefficient light collection and shading issues in solid-state imaging devices.
Innovation Solution
The optical element array features a design with varying widths and curvature radii along its cross-sections, optimizing the arrangement of optical elements to maximize light collection while maintaining a high area occupancy ratio, with specific configurations that enhance light gathering efficiency and reduce shading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a teardrop form microlens is used, then light collection from diagonal direction is improved, but area occupancy ratio decreases
Solution Approach 1:
The microlens is divided into multiple regions (first region, second region, third region) with different width characteristics along the radial direction. The first region has a wider width to collect diagonal light, while the second region has a narrower width to fit more lenses in the array, resolving the contradiction between light collection and area occupancy.
Solution Approach 2:
Different regions of the microlens are designed with different local characteristics: the first region (closer to center) has larger width for light collection, while the second region (outer edge) has smaller width for compact arrangement. This local differentiation allows the lens to simultaneously achieve good light collection and high area occupancy ratio.
2Shape
If a teardrop form microlens with small radius of curvature is used, then compact shape is achieved, but light collection ability is limited
Solution Approach 1:
The microlens employs different curvature radii in different regions: the first region has a larger curvature radius to maintain light collection ability, while the third region has a smaller curvature radius to achieve compact shape. This local differentiation resolves the contradiction between compactness and light collection.
Solution Approach 2:
The lens is segmented into multiple regions with progressively different curvature characteristics. The first region maintains larger curvature for light collection, while outer regions use smaller curvature for compactness, allowing the overall lens to be both compact and effective at light collection.
3Ease of manufacture
If microlenses are arranged in a regular array, then manufacturing is simplified, but light collection efficiency decreases due to spacing requirements
Solution Approach 1:
The microlens design incorporates variable width and curvature characteristics that dynamically adapt to different radial positions in the array. This allows the lenses to be packed more efficiently in the array while maintaining optimal light collection properties at each position, improving both manufacturing ease and light collection efficiency.
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 design significantly improves the light collecting ratio and area occupancy ratio, allowing for more efficient light collection and reduced shading, compared to traditional teardrop-shaped microlens arrays, with an increased pixel sensitivity and improved image quality.
Implementation Method 1
a first curvature radius and a first height that is the highest point within a first cross section when the first cross section is taken along the second direction at the first position, and a second curvature radius larger than the first curvature radius and a second height lower than the first height
Data Source
AI summary
An optical element array includes a plurality of optical elements arranged along a first direction and a second direction. A first optical element is included at a position distanced from a center of the optical element array by a first distance. The first optical element has a first width, a first height, and a first curvature radius at the first position, and a second width, a second height, and a second curvature radius at a second position. The first width is wider than the second width, the first height is higher than the second height, and the first curvature radius is smaller than the second curvature radius. The first position and the second position are taken along a single direction.