Solid-State Imaging Pixel Phase Detection Waveguide
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Solution Overview
Problem
Existing solid-state imaging apparatuses face challenges in fabrication ease and distance measuring accuracy, particularly due to the need for separate manufacturing processes for distance measuring and imaging pixels, and the reduction in pixel size leading to smaller photoelectric conversion areas and decreased signal amounts, as well as light interference from various angles.
Innovation Solution
A solid-state imaging apparatus with a phase difference detection pixel that includes a photoelectric conversion section, a waveguide, and a light-shielding section formed near the waveguide opening to shield incident light, which may also feature an on-chip lens and a light-shielding wall to prevent light leakage, improving light guidance and retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sub-waveguides are provided for each photoelectric conversion section to improve light guidance, then distance measuring accuracy is improved, but device complexity increases and fabrication becomes more difficult
Solution Approach 1:
The patent merges the light guidance function for multiple photoelectric conversion sections into a single waveguide structure instead of providing separate sub-waveguides for each section. This unified waveguide design simplifies the overall structure and reduces fabrication complexity while still achieving effective light guidance to all photoelectric conversion sections.
Solution Approach 2:
The single waveguide structure serves multiple functions by guiding light to all photoelectric conversion sections simultaneously. This multi-functional design eliminates the need for dedicated sub-waveguides for each section, reducing device complexity while maintaining distance measuring accuracy.
2Productivity
If pixel size is reduced to increase the number of pixels, then imaging resolution is improved, but photoelectric conversion area decreases and signal amount reduces
Solution Approach 1:
The patent combines multiple photoelectric conversion sections within a single pixel structure, allowing the pixel to function as both an imaging pixel and a distance measuring pixel. This merging enables the system to maintain adequate signal amounts for distance measurement while increasing the overall number of pixels through pixel size reduction.
Solution Approach 2:
The pixel is designed to serve dual functions: imaging and distance measurement. By making the pixel multi-functional, the system can reduce pixel size to increase pixel density while still maintaining the photoelectric conversion area necessary for accurate distance measurement through the integrated multiple photoelectric conversion sections.
3Measurement precision
If light-shielding film is provided above photoelectric conversion section to block stray light, then distance measuring accuracy is improved, but light from various angles is mixed and accuracy decreases
Solution Approach 1:
The patent extracts the light-shielding function from a film structure and implements it through wall structures (light-shielding walls) positioned around the waveguide and photoelectric conversion sections. This extraction allows for more selective and effective light blocking that prevents stray light interference while maintaining the ability to detect light from specific angles for accurate distance measurement.
Solution Approach 2:
The light-shielding walls act as intermediary structures that selectively block harmful stray light while allowing useful light to reach the photoelectric conversion sections through the waveguide. These walls mediate between the incoming light and the photoelectric conversion sections, filtering out interference from various angles while preserving the measurement signal.
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 simplifies the manufacturing process, enhances distance measuring accuracy by optimizing light guidance and retention, and prevents light interference, thereby improving the overall performance of the solid-state imaging apparatus.
Implementation Method 1
a photoelectric conversion section that is formed on a semiconductor substrate and configured to photoelectrically convert incident light
Implementation Method 2
a waveguide configured to guide the incident light to the photoelectric conversion section
Data Source
AI summary
A solid-state imaging apparatus includes a phase difference detection pixel including a photoelectric conversion section that is formed on a semiconductor substrate and configured to photoelectrically convert incident light, a waveguide configured to guide the incident light to the photoelectric conversion section, and a light-shielding section that is formed in vicinity of an opening of the waveguide and configured to shield a part of the incident light that enters the waveguide.