Direct-Hybridized Optical Filter Assembly for Precise Sensor Alignment
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Solution Overview
Problem
Existing methods for mounting optical filters in optical sensors are either costly, prone to alignment variations, and introduce structural elements that affect optical performance or require lengthy curing times with adhesives that can distort and attenuate light.
Innovation Solution
A direct hybridization method using Indium strips and spheres to mount a planar spectral filter with similar dimensions to the detector layer, eliminating the need for intermediate structures and ensuring precise alignment without adhesive interference in the optical path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive is used to mount the filter, then the filter can be mounted to the detector layer, but the adhesive introduces structural elements that distort and attenuate light in the optical path
Solution Approach 1:
The patent removes the adhesive layer from the optical path by directly bonding the filter to the detector layer through the mount structure. This extraction eliminates the harmful adhesive-induced light distortion and attenuation while maintaining the filter's functional mounting to the detector assembly.
Solution Approach 2:
The patent introduces a mount structure as an intermediary component between the filter and detector layer. This mount structure provides mechanical support and alignment without introducing optical interference, serving as a non-optical mediator that resolves the conflict between secure mounting and optical clarity.
2Ease of manufacture
If adhesive is used to mount the filter, then the filter can be secured to the detector layer, but the adhesive requires lengthy curing times
Solution Approach 1:
The patent replaces the chemical bonding mechanism (adhesive curing) with a mechanical bonding system (direct hybridization through the mount structure). This substitution eliminates the lengthy curing time requirement while maintaining secure filter mounting, as mechanical bonding provides immediate structural integrity.
3Manufacturing precision
If a mounting structure is introduced to align the filter, then alignment precision can be improved, but the structure may introduce elements into the optical path or contaminate the active area
Solution Approach 1:
The patent applies local quality by positioning the mount structure exclusively at the periphery of the detector layer, away from the optically active area. This localized placement provides precise alignment functionality while ensuring that no structural elements obstruct or contaminate the optical path over the active detection region.
Solution Approach 2:
The patent resolves the alignment-contamination conflict by moving the mounting structure to a different spatial dimension - the peripheral region rather than the central optical path. This dimensional relocation allows the mount to perform its alignment function without interfering with light transmission over the active area.
4Reliability
If expensive equipment and processes are used for hybridization, then reliable metal interconnects can be formed, but the assembly cost increases
Solution Approach 1:
The patent applies universality by using the same direct hybridization process and mount structure for both electrical interconnection and optical filter mounting. This multi-functional approach consolidates what would otherwise require separate expensive processes, achieving reliable connections while reducing overall assembly complexity and cost.
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 reduces assembly costs, improves optical performance by eliminating adhesive-induced distortions, and enhances thermal stability by allowing the filter to be closely coupled with the detector layer, minimizing thermal mass and maintaining precise alignment.
Implementation Method 1
a detector layer configured to detect incident light in an optically active area by converting photons to electrical charge
Implementation Method 2
pressing the detector layer onto the ROIC to 'cold fuse' the bumps to form a metal interconnect
Data Source
AI summary
An optical sensor and filter assembly is provided and includes an optical sensor, a filter and a mounting structure. The optical sensor includes a detector layer having first and second opposed faces and a read-out integrated circuit (ROIC) to which the first face of the detector layer is hybridized. The filter permits passage of one or more wavelength bands of interest of incident light toward the optical sensor and the mounting structure directly hybridizes the filter to the second face of the detector layer.