Backside Illumination Pixel Inner Lens Dielectric Barrier
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Solution Overview
Problem
Back-side illumination solid-state imaging apparatuses suffer from image quality deterioration due to multiple reflections of light entering the photoelectric conversion portion, primarily caused by the proximity of the metal light-shielding member to the inner lenses and the substrate, which is exacerbated by the smaller distance between the metal light-shielding member and the substrate in this structure compared to front-side illumination systems.
Innovation Solution
The solution involves a solid-state imaging apparatus with a substrate having photoelectric conversion portions and a light-shielding member, where the openings in the light-shielding member are strategically positioned to separate adjacent inner lenses with a dielectric member of different refractive indices, reducing multiple reflections by preventing light from entering the photoelectric conversion portion through the light-shielding member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the inner lenses are maximized in width to improve light sensitivity, then light sensitivity is improved, but multiple reflection increases causing image quality deterioration
Solution Approach 1:
A dielectric member is introduced as an intermediary substance between adjacent inner lenses. This dielectric member has a refractive index different from that of the inner lenses, creating an optical barrier that prevents light from reflecting between adjacent lenses. This allows the inner lenses to be maximized in width for improved light sensitivity while eliminating the harmful multiple reflection effect.
Solution Approach 2:
The refractive index parameter is changed by introducing a dielectric member with a different refractive index between adjacent inner lenses. This parameter change creates an optical discontinuity that prevents light reflection, thereby resolving the contradiction between maximizing lens width for sensitivity and preventing multiple reflection for image quality.
2Device complexity
If the distance between the light-shielding member and the substrate is reduced to improve integration, then device integration is improved, but susceptibility to multiple reflection increases
Solution Approach 1:
The dielectric member serves as an intermediary optical barrier between the inner lenses and the light-shielding member. By placing this substance with different refractive index in the gap between components, the patent prevents multiple reflection while maintaining the compact integrated structure, thus resolving the contradiction between device integration and multiple reflection susceptibility.
3Object-affected harmful factors
If openings in the light-shielding member are positioned to separate adjacent inner lenses, then multiple reflection is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The dielectric member is designed to automatically fill the gap between adjacent inner lenses through self-alignment during the manufacturing process. This self-service approach allows the openings in the light-shielding member to be positioned for optimal multiple reflection prevention while reducing the stringency of manufacturing precision requirements, as the dielectric member compensates for minor positioning 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 effectively reduces the amount of light entering the photoelectric conversion portion due to multiple reflections, thereby improving the image quality of the back-side illumination solid-state imaging apparatus by maximizing the width of the inner lenses and minimizing light leakage.
Implementation Method 1
a lens in the first pixel and the lens in the second pixel are separated from each other through a dielectric member with a refractive index different from that of the lens in the first pixel and that of the lens in the second pixel
Data Source
AI summary
A back-side illumination solid-state imaging apparatus, comprising a light-shielding member including a plurality of openings, and a plurality of pixels corresponding to the plurality of openings, wherein each pixel includes a photoelectric conversion portion, a microlens and an inner lens, the inner lens of a first pixel of an Mth row×an Nth column and the inner lens of a second pixel of an (M+1)th row×an (N+1)th column are separated from each other through a dielectric member, and the dielectric member contacts with part of the light-shielding member between a first opening corresponding to the first pixel and a second opening corresponding to the second pixel.