Image Sensor Light Distributing Element for Pixel Convergence
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Solution Overview
Problem
Image sensors face challenges in improving performance due to reduced light sensitivity and difficulty in converging incident light onto smaller sensing pixels, especially as the number of pixels increases and pixel size decreases.
Innovation Solution
The implementation of a plurality of sensing pixels with micro-lenses and first light distributing elements, comprising refractive index patterns, which converge incident light effectively onto the sensing pixels through refractive index differences and strategic positioning, enhancing light sensitivity and image sensor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of sensing pixels is increased and the size of each sensing pixel is reduced, then the resolution of the image sensor is improved, but the incident light cannot be easily converged to the corresponding sensing pixel
Solution Approach 1:
The light distributing element is divided into multiple regions, with each region corresponding to a specific sensing pixel. Each region contains refractive index patterns that independently guide light to its designated pixel, enabling effective light convergence even as pixel size decreases and pixel count increases.
Solution Approach 2:
Different regions of the light distributing element have different refractive index patterns tailored to their corresponding sensing pixels. The refractive index varies locally to optimize light convergence for each specific pixel location, maintaining effective light guidance across the entire sensor array despite varying pixel dimensions.
2Ease of manufacture
If a metal circuit layer is disposed above the sensing pixels to enable electrical connections, then the electrical connectivity is improved, but the light sensitivity of the image sensor is reduced due to blocking
Solution Approach 1:
The light distributing element is positioned in a third dimension above the sensing pixels and metal circuit layer. By operating in this additional spatial dimension, the element can guide light around the metal circuit layer obstacles and deliver it to the sensing pixels without being blocked by the planar metal connections.
Solution Approach 2:
The light distributing element acts as an intermediary optical component between the incident light and the sensing pixels. It mediates the light path by refracting and directing light through regions above the metal circuit layer, allowing light to reach the pixels without passing through the blocking metal structures.
3Reliability
If conventional light guides are used to converge light onto sensing pixels, then light distribution can be achieved, but the manufacturing process becomes complex and costs increase
Solution Approach 1:
The light distributing element integrates multiple functions into a single component: light guidance, refractive index modulation, and pixel-specific light distribution. By combining these functions that would traditionally require separate components, the manufacturing process is simplified while maintaining effective light convergence capability.
Solution Approach 2:
The invention utilizes variations in refractive index as a controllable parameter to achieve light convergence and distribution. By modifying the refractive index pattern within the light distributing element, complex light guidance functions are achieved through material property changes rather than complex geometric structures, reducing manufacturing complexity.
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 effectively converges incident light onto the sensing pixels, improving image sensor performance and sensitivity, while simplifying the manufacturing process and reducing costs compared to conventional light guides.
Implementation Method 1
Each of the first light distributing elements includes a first refractive index pattern and a second refractive index pattern surrounding the first refractive index pattern. The refractive index of the first refractive index pattern is larger than the refractive index of the second refractive index pattern.
Data Source
AI summary
An image sensor including a plurality of sensing pixels, a plurality of micro-lenses disposed on the sensing pixels and a plurality of first light distributing elements disposed between the sensing pixels and the micro-lenses is provided. Each of the first light distributing elements includes a first refractive index pattern and a second refractive index pattern surrounding the first refractive index pattern. The refractive index of the first refractive index pattern is larger than the refractive index of the second refractive index pattern.