Immersion Lens Detector Pixels for High-NA Photon Collection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electromagnetic radiation detectors face challenges in reducing shot noise from dark current, which degrades the signal-to-noise ratio, particularly when trying to minimize the detector pixel area to decrease dark current, as this also reduces the number of photons that can be collected.
Innovation Solution
The integration of an immersion lens directly bonded to the detector pixel without adhesives, eliminating air and adhesive-related issues, allows for increased numerical aperture and improved signal-to-noise ratio by focusing photons onto a smaller collection area while maintaining the benefits of separate manufacturing for the lens and detector pixel stack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the detector pixel area is minimized to decrease dark current, then the shot noise from dark current is reduced, but the number of photons that can be collected is also reduced
Solution Approach 1:
The patent merges the lens and detector pixel into a single integrated structure where the lens is formed as part of the detector pixel stack. This integration allows the lens to be positioned extremely close to the absorber with no air gaps, maximizing the numerical aperture and photon collection efficiency while maintaining a small pixel area to keep dark current low.
Solution Approach 2:
The patent extends the optical collection in the angular dimension by achieving a numerical aperture greater than 1.0 through the integrated lens structure. This dimensional approach to light collection allows capturing photons from a wider range of incident angles without increasing the pixel footprint, thus resolving the contradiction between small area and high photon collection.
2Ease of manufacture
If adhesive is used to bond the lens to the detector pixel, then the lens can be attached to the detector pixel, but the adhesive thickness limits the numerical aperture and introduces air gaps
Solution Approach 1:
The lens and detector pixel are merged into a single monolithic structure formed through epitaxial growth. This eliminates the need for adhesive bonding entirely, removing the limiting factor of adhesive thickness and enabling a numerical aperture greater than 1.0 without air gaps between the lens and absorber.
Solution Approach 2:
The patent uses epitaxial layers as an intermediary medium to integrate the lens and detector pixel. These layers serve as both the structural foundation for the lens and the active detection region, providing a seamless transition between optical and detection functions without requiring external adhesives.
3Ease of manufacture
If the lens is formed separately and bonded to the detector pixel stack, then the lens and detector can be manufactured independently, but the bonding process introduces complexity and potential misalignment
Solution Approach 1:
The lens and detector pixel are formed together in a single epitaxial growth process, eliminating the separate bonding step and associated alignment complexities. The integrated structure is manufactured as one unified component, simplifying the overall manufacturing process while maintaining the ability to independently design lens and detector parameters.
Solution Approach 2:
While integrated, the structure maintains functional segmentation with distinct lens and absorber regions formed through controlled epitaxial growth. This allows independent optimization of each component's properties during the growth process without requiring physical separation or bonding steps.
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 approach enhances the signal-to-noise ratio by increasing the range of position and incident angle pairs that can be collected, reducing the impact of buffer layers, and allowing for higher numerical aperture without the limitations of current adhesive thickness, thereby improving the detection efficiency of electromagnetic radiation.
Implementation Method 1
An immersion lens may be directly bonded to a layer of material forming part of the electromagnetic radiation detector
Implementation Method 2
allows for increased numerical aperture and improved signal-to-noise ratio by focusing photons onto a smaller collection area
Implementation Method 3
The set of epitaxial layers may define an electromagnetic radiation absorber
Data Source
AI summary
An electromagnetic radiation detector pixel includes a set of epitaxial layers and a lens. The set of epitaxial layers defines an electromagnetic radiation absorber. The lens is directly bonded to the set of epitaxial layers.