Image Sensor Aperture Layout for Uniform Pixel Light Distribution
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Solution Overview
Problem
Solid-state image sensors with small pixels face challenges such as reduced sensitivity and uneven light distribution due to smaller light-receiving areas and light scattering into isolation structures, affecting image quality.
Innovation Solution
The design incorporates a semiconductor substrate with photoelectric conversion elements and a modulation layer featuring different aperture ratios in various pixel regions, utilizing a light-adjusting structure like micro-lenses and a grid structure to optimize light allocation and prevent light concentration into isolation structures, thereby improving image signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pixel size is reduced to increase resolution, then the number of pixels increases, but the light-receiving area decreases causing lower sensitivity
Solution Approach 1:
The patent applies local quality by differentiating aperture ratios across different pixel regions. Specifically, pixels are divided into first pixel regions with a first aperture ratio and second pixel regions with a second aperture ratio that is larger than the first. This allows each region to be optimized for its specific function: higher resolution in certain areas while maintaining sufficient light reception in others, thereby resolving the contradiction between small pixel size and light-receiving area.
2Illumination intensity
If a single micro-lens is used to increase light collection, then quantum efficiency increases, but light distribution becomes uneven across pixels
Solution Approach 1:
The patent applies segmentation by dividing the pixel array into multiple pixel regions, each with its own aperture ratio characteristics. Instead of using a single micro-lens for the entire array, the system segments the light collection function across different regions with differentiated aperture ratios. This segmentation allows each region to receive appropriate light intensity while maintaining overall uniformity across the sensor array.
3Ease of manufacture
If light is concentrated into isolation structures, then manufacturing becomes simpler, but light scattering increases reducing image quality
Solution Approach 1:
The patent applies parameter changes by modifying the aperture ratio parameter across different pixel regions. By adjusting the aperture ratio as a key parameter, the system optimizes light distribution to prevent light concentration into isolation structures. The differentiated aperture ratios ensure that light is directed appropriately toward photoelectric conversion elements while minimizing scattering into isolation structures, thus improving image quality without complicating manufacturing.
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 approach enhances pixel uniformity and image quality by optimizing light distribution across the sensor, preventing light scattering and ensuring more uniform light intensity across the photoelectric conversion elements.
Implementation Method 1
The solid-state image sensor includes a light-adjusting structure disposed on the modulation layer and corresponding to the N×N pixel array
Implementation Method 2
Signal electric charges may be generated according to the amount of light received in the light-sensing portion (e.g., photoelectric conversion element) of the solid-state image sensor
Data Source
AI summary
A solid-state image sensor is provided. The solid-state image sensor includes a semiconductor substrate having photoelectric conversion elements. The photoelectric conversion elements form an N×N pixel array, where N is a positive integer larger than or equal to 3. The solid-state image sensor also includes a modulation layer disposed above the photoelectric conversion elements. The solid-state image sensor further includes a light-adjusting structure disposed on the modulation layer and corresponding to the N×N pixel array. The N×N pixel array includes a first pixel region having at least one first pixel. The N×N pixel array also includes a second pixel region adjacent to the first pixel region in a first direction and in a second direction different from the first direction and having second pixels. The aperture ratio of the first pixel and the aperture ratio of the second pixel are different.