Image Sensor Grid Structure for Phase Detection Crosstalk Control
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Solution Overview
Problem
Current image sensing devices face challenges in achieving high phase detection characteristics while maintaining low power consumption and miniaturization, particularly in applications requiring both image and phase information.
Innovation Solution
The implementation of an image sensing device with phase detection pixels, a grid structure comprising a metal layer and a low-refraction index layer, and color filters arranged to prevent crosstalk, allowing for improved phase detection and low-exposure pixel signal acquisition using a single exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a grid structure is added between color filters to reduce crosstalk and improve phase detection, then phase detection characteristics are improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The grid structure is segmented into multiple discrete grid lines positioned between color filters and between the first color filter and the second color filter. This segmentation allows each grid line to independently block stray light in specific directions, reducing crosstalk between adjacent pixels while maintaining phase detection capability. The segmented approach simplifies manufacturing compared to a continuous grid structure.
Solution Approach 2:
The grid structure acts as an intermediary element positioned between the color filters and the pixel array. It mediates the optical paths by blocking stray light that would otherwise cause crosstalk, while allowing the desired optical signals to pass through to the respective pixels. This intermediary structure enables improved phase detection without requiring fundamental changes to the pixel design.
2Measurement precision
If multiple color filters and grid structures are layered to improve phase detection and reduce crosstalk, then optical signal quality is improved, but light transmission efficiency decreases
Solution Approach 1:
The grid structure is designed with local quality variations where grid lines are positioned only in critical areas where stray light causes crosstalk. The grid lines have optimized dimensions and spacing to block only the harmful stray light paths while allowing the majority of useful light to reach the pixels. This localized approach maintains high light transmission efficiency while improving optical signal quality.
Solution Approach 2:
The grid structure parameters such as line width, spacing, and position are optimized to achieve the right balance between blocking stray light and transmitting useful light. By carefully controlling these parameters, the system achieves improved phase detection characteristics while minimizing the impact on light transmission efficiency.
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
Enhances phase detection capabilities and reduces power consumption by effectively filtering incident light and minimizing crosstalk between color filters, enabling efficient image capture with improved structural characteristics.
Implementation Method 1
a first grid disposed not only between the first color filters, but also between each of the first color filters and the second color filter; and a second grid disposed between the first color filter and the second color filter
Implementation Method 2
at least one phase detection pixel configured to perform conversion of incident light received through a second color filter; a plurality of color filters placed over the image pixel array... to filter incident light
Implementation Method 3
phase detection pixels configured to perform conversion of incident light received through a second color filter so as to generate a phase signal
Implementation Method 4
a plurality of image pixels configured to perform conversion of incident light received through at least one first color filter so as to generate image signals
Data Source
AI summary
An image sensing device includes a plurality of image pixels, phase detection pixels, a first grid structure, and a second grid structure. The image pixels perform conversion of incident light received through at least one first color filter so as to generate image signals indicative of a target object to be captured. The phase detection pixels perform conversion of incident light received through a second color filter so as to generate a phase signal for calculating a phase difference between images formed by the image signals. The first grid structure is disposed between any two of the first color filters and between any one of the first color filters and any one of the second color filters. The second grid structure is located adjacent to the first grid structure and disposed between any one of the first color filters and any one of the second color filter.