Light Guide Portion Refractive Index Distribution for Image Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing photoelectric conversion apparatuses face challenges in accurately distributing light to multiple photodiodes, leading to reduced sensitivity and inefficient light transfer due to uniform refractive indices in light guide portions.
Innovation Solution
Incorporating a light guide portion with a refractive index distribution, featuring a high refractive index part and a low refractive index part, surrounded by an insulation film, to guide light more accurately to photoelectric conversion portions, enhancing sensitivity and transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform refractive index is used in the light guide portion, then the structure is simple and easy to manufacture, but light distribution accuracy and sensitivity are reduced
Solution Approach 1:
The light guide portion is divided into regions with different refractive indices: a first light guide region with refractive index n1 and a second light guide region with refractive index n2 (where n1 > n2). This local differentiation allows precise control of light distribution to respective photoelectric conversion portions while maintaining manufacturing feasibility through selective material deposition or doping processes.
Solution Approach 2:
The refractive index parameter is changed spatially within the light guide portion to optimize light distribution. By setting different refractive indices in different regions, the patent achieves improved light transfer efficiency and sensitivity without requiring complete structural redesign, thus resolving the contradiction between manufacturing simplicity and optical performance.
2Measurement precision
If clearances are provided in the interlayer film around photodiodes, then light distribution between photodiodes can be controlled, but sensitivity is lowered and light transfer efficiency is reduced
Solution Approach 1:
Instead of using physical clearances in the interlayer film, the patent changes the refractive index parameter within the light guide portion itself. The first and second light guide regions have different refractive indices that naturally guide light to the appropriate photoelectric conversion portions, eliminating the need for clearance structures and thereby maintaining high light transfer efficiency while achieving precise light distribution control.
Solution Approach 2:
The mechanical clearance structure in the interlayer film is replaced by an optical field-based solution using refractive index differentiation. This substitution eliminates the need for physical separations that cause light loss, while achieving the same light distribution control function through optical parameter optimization.
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 refractive index distribution in the light guide portion improves light distribution accuracy and sensitivity by concentrating light near high refractive index areas, effectively addressing the limitations of uniform refractive index designs.
Implementation Method 1
the light guide portion includes: a high refractive index part having a refractive index higher than a refractive index of the insulation layer; and a low refractive index part having a refractive index higher than the refractive index of the insulation layer and lower than the refractive index of the high refractive index part
Data Source
AI summary
A photoelectric conversion apparatus including a light-receiving element, including: a plurality of photoelectric conversion portions; a separating portion located between the plurality of photoelectric conversion portions; and a light guide portion surrounded by an insulation film including at least one insulation layer and provided so as to extend over the plurality of photoelectric conversion portions, and the light guide portion includes: a high refractive index part having a refractive index higher than a refractive index of the insulation layer; and a low refractive index part having a refractive index higher than the refractive index of the insulation layer and lower than the refractive index of the high refractive index part, and the high refractive index part is located on each of the plurality of photoelectric conversion portions and the low refractive index part is located on the separating portion.