Pixel Isolation Layout for Gr/Gb Signal Separation
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Solution Overview
Problem
Existing image sensing devices face challenges in minimizing optical loss and improving the signal difference between Gr and Gb pixels, leading to deterioration in image quality.
Innovation Solution
The implementation of a pixel array structure with specific isolation regions, including first, second, and third isolation regions, which are designed to scatter light in a direction orthogonal to the inner isolation regions, thereby minimizing optical loss and improving signal difference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional isolation regions are used in image sensing devices, then manufacturing is simpler, but optical loss increases and Gr/Gb signal difference deteriorates
Solution Approach 1:
The isolation region is divided into multiple segments: a first isolation region at the edge, a second isolation region extending inward, and a third isolation region crossing between inner isolation regions. This segmentation allows each part to perform specific functions in light scattering, reducing overall optical loss while maintaining manufacturability through modular structure design.
Solution Approach 2:
Different regions of the isolation structure are designed with different properties: the first isolation region is positioned at the edge for initial light scattering, the second isolation region extends toward the center for additional scattering control, and the third isolation region crosses between inner regions to optimize Gr/Gb signal differentiation. Each local region is optimized for its specific function to minimize overall optical loss.
2Measurement precision
If conventional isolation regions are used, then device structure is simpler, but Gr/Gb signal difference deteriorates
Solution Approach 1:
The isolation structure is segmented into first, second, and third isolation regions with distinct spatial arrangements. The third isolation region specifically crosses between the inner isolation regions of adjacent pixels, creating asymmetric light scattering patterns that enhance the Gr/Gb signal difference for improved measurement precision.
Solution Approach 2:
The third isolation region is positioned asymmetrically to cross between the inner isolation regions, creating different light scattering characteristics for Gr and B pixels. This asymmetric design exploits the directional scattering properties to maximize the signal difference between green and blue channels.
3Measurement precision
If light scattering is increased to improve signal difference, then optical loss increases
Solution Approach 1:
Light scattering is enhanced locally at specific isolation regions (particularly the third isolation region crossing between inner regions) to improve Gr/Gb signal difference, while other regions maintain optimized scattering properties to minimize overall optical loss. This localized enhancement achieves signal differentiation without proportionally increasing total light loss.
Solution Approach 2:
The patent converts the potentially harmful effect of light scattering (which typically causes optical loss) into a beneficial effect by strategically positioning the third isolation region to scatter light in directions that differentiate Gr and B signals while minimizing loss into non-sensitive regions. The scattering that would normally be waste is redirected to serve the signal differentiation function.
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 enhances the output signal difference between Gr and Gb pixels, achieving a value closer to 1 while minimizing optical loss, thereby improving image quality and reducing crosstalk.
Implementation Method 1
designed to scatter light in a direction orthogonal to the inner isolation regions, thereby minimizing optical loss and improving signal difference
Data Source
AI summary
In an embodiment, an image sensing device includes a pixel array including a plurality of unit pixels, wherein each of the unit pixels comprises a plurality of sub-pixels, wherein a first isolation region is formed in an edge region of the plurality of sub-pixels, wherein a second isolation region is formed from the first isolation region toward a central portion of each of the sub-pixels, wherein the second isolation region comprises: a first inner isolation region protruding from one region of the first isolation region toward the central portion of the sub-pixel; and a second inner isolation region aligned with the first inner isolation region and protruding from another region of the first isolation region toward the central portion of the sub-pixel, wherein a third isolation region is formed in a direction orthogonal to a direction in which the first inner isolation region and the second inner isolation region.