Light Path Member Refractive Index Distribution for Photoelectric Sensitivity
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Solution Overview
Problem
In photoelectric conversion apparatuses, reducing the width of the light receiving surface to increase the number of conversion portions or reduce the apparatus size leads to deteriorated sensitivity due to inefficient use of incident light, necessitating improved light guiding mechanisms.
Innovation Solution
A light path member with a refractive index distribution, featuring a first high refractive index region and a second high refractive index region, is integrated into the photoelectric conversion element, surrounded by an insulator film, to enhance light guiding and reduce loss, with the refractive index of the second region being higher than the first and the insulator film, and varying thickness to optimize light propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the width of the light receiving surface is reduced to increase the number of photoelectric conversion portions or reduce the apparatus size, then the number of conversion portions increases or the apparatus size reduces, but the sensitivity of the photoelectric conversion portions deteriorates
Solution Approach 1:
The light path member is provided with a specific refractive index distribution where a first high refractive index region and a second high refractive index region are positioned at different locations. This local variation in refractive index optimizes light guidance differently in various regions, allowing efficient light collection even with a reduced light receiving surface width, thereby maintaining sensitivity while increasing the number of photoelectric conversion portions.
Solution Approach 2:
The patent changes the refractive index parameter of the light path member by creating regions with different refractive indices (first high refractive index region and second high refractive index region). This parameter variation enables better control of light propagation paths, improving light use efficiency and maintaining photoelectric conversion sensitivity despite the reduced light receiving surface width.
2Volume of moving object
If the width of the light receiving surface is reduced, then the apparatus size reduces, but the use efficiency of incident light deteriorates
Solution Approach 1:
By providing local quality variations in the form of specific refractive index regions within the light path member, the patent optimizes light guidance in different areas. This allows the apparatus to maintain compact size while efficiently guiding incident light to the photoelectric conversion portions, preventing light loss even with the reduced light receiving surface width.
Solution Approach 2:
The light path member has a lens-shaped configuration with curved surfaces that are convex toward the light receiving surface. This curvature helps to focus and guide incident light effectively through the compact structure, improving light use efficiency while maintaining a reduced apparatus size.
3Use of energy by moving object
If a light waveguide path is provided onto the light receiving surface to improve light use efficiency, then the use efficiency of incident light improves, but the device complexity increases
Solution Approach 1:
The patent merges the light guiding function directly into the light path member by providing a specific refractive index distribution within the member itself, rather than adding separate waveguide structures. This integration achieves improved light use efficiency while avoiding the complexity of multiple separate optical components.
Solution Approach 2:
Instead of adding complex waveguide structures, the patent achieves light guidance by changing the refractive index parameter within the light path member, creating first and second high refractive index regions. This parameter-based approach simplifies the device structure while maintaining effective light guidance and improved light use 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
This configuration improves the sensitivity and light use efficiency by effectively guiding incident light to the photoelectric conversion portion, reducing loss and enhancing F value linearity and sensitivity, especially for oblique incident light.
Implementation Method 1
the light path member including a first portion, and a second portion having the same stoichiometric composition as with the first portion, and also having a higher refractive index than the refractive index of the first portion
Data Source
AI summary
A member for light path to a photoelectric conversion portion includes a middle portion, and a peripheral portion having a refractive index different from the refractive index of the middle portion, and within some plane in parallel with the light receiving surface of a photoelectric conversion portion, and within other plane closer to the light receiving surface than the some plane in parallel with the light receiving surface, the peripheral portion is continuous with the middle portion and surrounds the middle portion, and also the refractive index of the peripheral portion is higher than the refractive index of an insulator film, and the thickness of the peripheral portion within the other plane is smaller than the thickness of the peripheral portion within the some plane.