Microlens Array with Varying Diameters for Image Sensor Quantum Efficiency
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Solution Overview
Problem
Existing image sensors, particularly those using backside illumination technology, have limitations in achieving high-quality image signals, as they do not effectively optimize light transmission across different microlenses, affecting image quality.
Innovation Solution
The image sensor incorporates a microlens array with first and second microlenses of varying diameters, where the first microlenses have larger diameters than the second microlenses, enhancing light transmission and quantum efficiency, particularly for green light, by strategically arranging them on the sensing layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform microlenses are used across the sensing layer, then manufacturing is simplified, but light transmission efficiency and quantum efficiency are insufficient
Solution Approach 1:
The patent applies local quality by varying microlens diameters based on their position in the array. Microlenses at different locations (edge vs center) have different diameters to compensate for non-uniform light distribution across the sensing layer, thereby optimizing quantum efficiency locally while maintaining a systematic manufacturing approach
2Reliability
If larger microlenses are used, then light transmission and quantum efficiency improve, but the complexity of the microlens array design increases
Solution Approach 1:
The patent changes the diameter parameter of microlenses systematically across the array. By varying this single geometric parameter based on position, the patent optimizes light transmission and quantum efficiency without introducing complex structural changes, maintaining manufacturing feasibility while improving performance
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 improves the quantum efficiency and image quality by increasing the amount of light passing through the first microlenses, specifically benefiting the green color channel, thereby enhancing the overall image generated by the sensor.
Implementation Method 1
since the diameter of the first microlens is greater than the diameter of the second microlenses, the quantity of light passing through the first microlens is greater than the quantity of light passing through the second microlens
Implementation Method 2
The first microlens is disposed on the sensing layer. The second microlenses are disposed on the sensing layer adjacent to the first microlens
Data Source
AI summary
An image sensor includes a sensing layer, a first microlens, and a number of second microlenses. The first microlens is disposed on the sensing layer. The second microlenses are disposed on the sensing layer adjacent to the first microlens. The diameter of the first microlens is greater than the diameter of each of the second microlenses.