Optical Waveguide Height Optimization for Phase Difference Pixels
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Solution Overview
Problem
In solid-state imaging devices with phase difference AF, the optical properties of standard pixels are compromised due to the presence of light shielding films, leading to reduced light sensitivity and pupil separation performance when incident light comes from oblique directions.
Innovation Solution
The implementation of a solid-state imaging device with standard and phase difference pixels, where the standard pixel includes a first optical waveguide guiding incident light to a light receiving region, and the phase difference pixel includes a second optical waveguide and a first light shielding film on the upper layer side, with the upper ends of both waveguides at different heights, optimizing lens shapes and light shielding film placement to maintain optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the focal position of the on-chip lens is adjusted to the height of the light shielding film in the phase difference pixel, then the pupil separation performance is improved, but the optical properties of the standard pixel are degraded
Solution Approach 1:
The patent applies local quality by providing different optical waveguide structures to different pixel types. Standard pixels are equipped with optical waveguides optimized for light collection and sensitivity, while phase difference pixels have optical waveguides configured for pupil separation. This localized optimization allows each pixel type to have its own optimal optical properties without compromising the other.
Solution Approach 2:
The patent segments the optical waveguide structure into pixel-specific configurations. Rather than using a uniform waveguide design across all pixels, the optical waveguides are segmented and tailored to the specific functional requirements of standard pixels versus phase difference pixels, enabling independent optimization of each pixel type's optical characteristics.
2Illumination intensity
If optical waveguides are provided below the light shielding film, then light sensitivity of standard pixels is improved, but components that cannot be gathered may leak out when incident light from oblique directions increases
Solution Approach 1:
The patent applies parameter changes by adjusting the optical waveguide parameters (such as depth, width, refractive index profile, and configuration) to optimize light collection efficiency. By carefully controlling these parameters, the optical waveguides can effectively gather light from oblique directions while preventing light leakage, thus improving light sensitivity without compromising light gathering efficiency.
3Ease of manufacture
If the upper ends of optical waveguides in standard and phase difference pixels are at the same height, then manufacturing is simplified, but optical performance of both pixel types cannot be simultaneously optimized
Solution Approach 1:
The patent implements local quality by allowing the upper ends of optical waveguides to be at different heights depending on the pixel type. Standard pixels and phase difference pixels can have waveguides terminated at different elevations, enabling each pixel type to achieve its optimal optical performance while the manufacturing process remains feasible through localized structural variations.
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 optimizes the optical properties of both standard and phase difference pixels, enhancing light sensitivity and pupil separation performance while preventing light leakage from oblique directions.
Implementation Method 1
a first optical waveguide that guides incident light to a light receiving region
Data Source
AI summary
An imaging apparatus, for example, a solid-state imaging device, includes a phase difference pixel, and an electronic apparatus that optimizes the optical properties (pupil separation performance) of the phase difference pixel, and the optical properties (light sensitivity) of a standard pixel. The solid-state imaging device includes a standard pixel and a phase difference pixel. The standard pixel includes a first optical waveguide that guides incident light to a light receiving region. The phase difference pixel includes a second optical waveguide that guides incident light to the light receiving region, and a first light shielding film provided on the upper layer side of the second optical waveguide. The upper end of the first optical waveguide of the standard pixel and the upper end of the second optical waveguide of the phase difference pixel are located at different heights.