Phase Difference Pixel Lens With Tapered Light Condensing Layers
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Solution Overview
Problem
Existing phase difference detection pixels in image sensors suffer from a decrease in external signal input due to light blocking structures, leading to performance deterioration, especially in low illumination environments and at the edges of pixel arrays, which delays focus calculation and reduces productivity.
Innovation Solution
The use of a pixel lens with multiple light condensing layers, where upper layers have shorter widths than lower layers, and sidewalls are aligned, allowing for efficient light guidance into the photoelectric conversion layer without a shading mask, enhancing signal strength and light receiving area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light blocking structure is used in phase difference detection pixels, then phase difference detection capability is improved, but external signal input is decreased
Solution Approach 1:
The invention removes the light blocking structure (shading mask) from the pixel configuration. Instead of using a blocking structure to achieve phase difference detection, the patent extracts this component entirely and replaces it with a lensless pixel design that achieves phase difference detection through optical path differences in the microlens array configuration, thereby maintaining detection capability while eliminating signal loss.
Solution Approach 2:
The invention inverts the conventional approach by not blocking light to create phase difference, but rather allowing light to pass through while creating phase difference through the microlens optical paths. Instead of using a shading mask to block certain light paths, the patent uses the natural optical paths through different microlenses to create the necessary phase difference for depth detection.
2Measurement precision
If a light blocking structure is used in phase difference detection pixels, then phase difference detection is enabled, but image sensor performance is deteriorated
Solution Approach 1:
The invention extracts and removes the light blocking structure that was causing performance deterioration. By eliminating the shading mask, the patent prevents signal loss and maintains photoelectric conversion efficiency, thereby improving overall image sensor reliability while preserving phase difference detection functionality through alternative optical path design.
3Extent of automation
If a light blocking structure is used in phase difference detection pixels, then auto-focusing capability is achieved, but productivity is reduced
Solution Approach 1:
The invention removes the light blocking structure that was causing signal loss and delayed focus calculation. By eliminating the shading mask, the patent increases the amount of light reaching the photoelectric conversion layer, which improves signal strength and enables faster focus calculation, thereby enhancing productivity while maintaining auto-focusing 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 prevents signal strength decrease and improves image sensor performance by maximizing light reception and reducing the need for shading masks, enabling effective auto-focusing and three-dimensional image capture in various lighting conditions.
Implementation Method 1
a pixel lens, including a plurality of light condensing layers, formed over the photoelectric conversion layer
Data Source
AI summary
An image sensor includes: a photoelectric conversion layer; and a pixel lens, including a plurality of light condensing layers, formed over the photoelectric conversion layer, wherein upper layers of the plurality of light condensing layers have shorter widths than lower layers of the plurality of light condensing layers, wherein the light condensing layers of the pixel lens have their sidewalls of one side aligned with each other.