Solid-State Imaging Device Scatterer for Crosstalk Reduction
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Solution Overview
Problem
Solid-state imaging devices with distance measuring pixels face sensitivity degradation due to electron diffusion in element isolation regions, leading to reduced image quality and accuracy in distance measurement.
Innovation Solution
Incorporating a scatterer with a refractive index lower than the surrounding material within the pupil dividing portion above the element isolation region, which scatters light and enhances sensitivity by distributing it more efficiently to photoelectric conversion regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an element isolation region is arranged between photoelectric conversion regions to suppress crosstalk, then crosstalk is suppressed, but sensitivity degrades due to electron diffusion and light loss
Solution Approach 1:
A scatterer is introduced as an intermediary component between the pupil dividing portion and the element isolation region. This scatterer redirects light that would otherwise be lost in the element isolation region, mediating between the need for isolation and the need for sensitivity by redirecting stray light to useful photoelectric conversion regions
Solution Approach 2:
The element isolation region, which normally causes light loss and sensitivity degradation, is transformed into a beneficial structure. By placing a scatterer above it, the region that previously represented a harm (light loss) is converted into a benefit through scattered light redirection to photoelectric conversion regions, improving overall sensitivity
2Measurement precision
If light fluxes from different pupil regions are guided to different photoelectric conversion regions for distance measurement, then distance measurement accuracy is improved, but sensitivity degrades due to light loss in element isolation regions
Solution Approach 1:
The scatterer acts as an intermediary that recovers light energy lost in the element isolation region and redirects it to photoelectric conversion regions, reducing overall light loss while preserving the pupil-dividing distance measurement functionality
Solution Approach 2:
The refractive index parameter of the scatterer material is specifically chosen to be lower than the surrounding pupil dividing portion material. This parameter change creates the optical conditions necessary for effective light scattering and redirection, transforming the optical path to reduce energy loss
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
The solution effectively suppresses sensitivity degradation and enhances image quality while maintaining high accuracy in distance measurement by optimizing light distribution and reducing optical loss.
Implementation Method 1
a scatterer is provided within the pupil dividing portion and above the element isolation region
Implementation Method 2
the scatterer is formed from a material of a refractive index smaller than a refractive index of a material of the portion the pupil dividing portion peripheral to the scatterer
Data Source
AI summary
A solid-state imaging device includes a plurality of pixels, wherein one or more of the plurality of pixels have a pupil dividing portion and a light receiving portion, the light receiving portion includes a plurality of photoelectric conversion regions, an element isolation region is provided between adjacent ones of the plurality of photoelectric conversion regions, and wherein a scatterer is provided within the pupil dividing portion and above the element isolation region, and the scatterer is formed from a material of a refractive index smaller than a refractive index of a material of the pupil dividing portion peripheral to the scatterer.