Fractal Optical Surface for Infrared Light Diffusion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical devices, such as pixels and optical diffusers, suffer from low quantum efficiency and inadequate light diffusion, particularly for infrared light at wavelengths like 940 nm.
Innovation Solution
Incorporating a fractal structure on the light-facing face of the optical device, devoid of rotational symmetry, with recesses penetrating only a portion of the layer thickness, enhances light diffusion and increases quantum efficiency by maximizing optical path and reducing reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional structures are used on the light-facing face, then the device is simpler to manufacture, but quantum efficiency is low and light diffusion is inadequate
Solution Approach 1:
The light-facing face is segmented into multiple recesses of varying depths arranged in a fractal pattern, creating numerous light-trapping pathways that increase optical path length and quantum efficiency while maintaining a manufacturable structure through systematic segmentation
Solution Approach 2:
The invention transitions from conventional two-dimensional surface structures to a three-dimensional fractal architecture with recesses at multiple depth levels, creating a multi-scale structure that enhances light diffusion and absorption without proportionally increasing manufacturing complexity
2Reliability
If the layer is made thicker to increase optical path, then quantum efficiency improves, but light diffusion capability deteriorates
Solution Approach 1:
The thick layer is segmented into multiple recesses of different depths, creating numerous interfaces that scatter and diffuse light throughout the volume, thereby maintaining light diffusion capability while achieving increased optical path length for improved quantum efficiency
Solution Approach 2:
The fractal structure implements a nested arrangement where smaller recesses are positioned within and between larger recesses, creating a hierarchical multi-scale structure that maximizes light diffusion throughout the layer thickness while maintaining structural integrity
3Adaptability or versatility
If conventional diffusers are used, then manufacturing is simpler, but light diffusion and emission quality are insufficient
Solution Approach 1:
The diffuser surface is segmented into a fractal pattern of recesses that systematically distribute light across multiple scales, achieving superior diffusion quality through a structured approach that can be manufactured using standardized fabrication processes
Solution Approach 2:
The invention optimizes specific parameters including recess depth ratios, spacing, and fractal iteration levels to achieve optimal light diffusion while maintaining compatibility with conventional semiconductor manufacturing processes, balancing performance with manufacturability
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 fractal structure improves quantum efficiency and light diffusion, increasing the amount of light absorbed by the photosensitive area while minimizing reflections and cross-talk between pixels.
Implementation Method 1
structures modifying the direction of propagation of the light, which makes it possible to increase the optical path of the light in the photodiode
Implementation Method 2
the fractal structure comprising recesses penetrating the layer through only a portion of a thickness of the layer
Implementation Method 3
increase the optical path of the light in the photodiode, and thus the quantum efficiency of the pixel
Data Source
AI summary
An optical device includes a layer having a face configured to be traversed by light at an operating wavelength. The face of the layer includes a fractal structure lacking rotational symmetry such as a fractal structure that corresponds to a fractal expressed in an L-system. The fractal structure is formed by recesses that penetrate into the layer from the face. The recesses have a depth which is less that a thickness of the layer.