Multifunctional CIS Collimator Using Doped Silicon IR Filtering
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Solution Overview
Problem
Contact image sensors (CIS) face challenges in filtering ambient infrared noise effectively due to the use of thick glass filters, resulting in bulky and costly assemblies.
Innovation Solution
A method is developed to integrate a filter function into a collimator structure for CIS, using a thinned silicon substrate with high impurity doping to align incident light and filter ambient noise, allowing for a compact and cost-effective design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a thick glass filter is used to filter ambient infrared noise, then the filtering effectiveness is improved, but the assembly becomes bulky and costly
Solution Approach 1:
The patent merges the collimator and infrared filter into a single integrated component. The collimator is constructed with a light-absorbing material that inherently blocks infrared wavelengths, eliminating the need for a separate thick glass filter. This integration reduces the overall assembly volume while maintaining effective infrared noise filtering.
Solution Approach 2:
The collimator is designed to perform multiple functions simultaneously: it collimates the optical signal and filters ambient infrared noise. By using a light-absorbing material with specific properties, the single component achieves both functions that previously required separate elements, thereby reducing assembly bulk.
2Object-affected harmful factors
If a thick glass filter is used to filter ambient infrared noise, then the filtering effectiveness is improved, but the cost increases
Solution Approach 1:
The patent combines the collimator and infrared filter functions into one component, eliminating the need to manufacture and assemble a separate thick glass filter. This integration reduces part count, simplifies the manufacturing process, and lowers overall cost while maintaining infrared filtering effectiveness.
Solution Approach 2:
The integrated collimator-filter structure uses cost-effective light-absorbing materials that can be manufactured through standard semiconductor fabrication processes, replacing expensive thick glass filters. The design prioritizes cost-effective manufacturing without sacrificing filtering performance.
3Object-affected harmful factors
If a thick glass filter is used, then infrared noise filtering is improved, but the assembly complexity increases
Solution Approach 1:
The patent integrates the infrared filtering function directly into the collimator structure, reducing the number of discrete components from two (collimator + filter) to one. This integration simplifies the assembly process, reduces alignment requirements, and lowers overall device complexity while maintaining effective infrared noise filtering.
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 collimator structure effectively filters ambient infrared noise while maintaining a compact design, reducing the need for thick glass and lowering costs, enabling the use of CIS in space-limited applications.
Implementation Method 1
the substrate has a bulk impurity doping concentration equal to or greater than 1×10^19 per cubic centimeter (cm^-3) and a first thickness, and wherein the bulk impurity doping concentration and the first thickness of the substrate are configured so as to allow the optical collimator to filter light in a range of wavelengths
Data Source
AI summary
Disclosed is a method to fabricate a multifunctional collimator structure In one embodiment, an optical collimator, includes: a dielectric layer; a substrate; and a plurality of via holes, wherein the dielectric layer is formed over the substrate, wherein the plurality of via holes are configured as an array along a lateral direction of a first surface of the dielectric layer, wherein each of the plurality of via holes extends through the dielectric layer and the substrate from the first surface of the dielectric layer to a second surface of the substrate in a vertical direction, wherein the substrate has a bulk impurity doping concentration equal to or greater than 1×1019 per cubic centimeter (cm−3) and a first thickness, and wherein the bulk impurity doping concentration and the first thickness of the substrate are configured so as to allow the optical collimator to filter light in a range of wavelengths.