Variable-Focal-Length Phased Metalens for Camera Lens Centration
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Solution Overview
Problem
Camera assemblies face challenges in achieving consistent MTF performance due to variations in lens focus caused by subtle assembly conditions, leading to high scrap rates and increased production costs from failed end-of-line tests.
Innovation Solution
Utilize a variable focal length phased metalens during the camera modular alignment and test process to measure and align lens centration vectors with the image sensor boresight, improving MTF performance by compensating for defocusing effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional lens alignment methods are used, then the alignment process is simple, but the MTF performance becomes inconsistent due to assembly variations
Solution Approach 1:
The patent introduces a simulated lens assembly as an intermediary component between the test lens and the image sensor. This simulated assembly includes virtual lens elements and optical paths that replicate the actual lens behavior without requiring physical lens components. The intermediary allows for precise measurement of optical characteristics and alignment parameters while eliminating the complexity of working with actual lenses during alignment procedures.
Solution Approach 2:
The patent creates a digital copy or simulation of the lens optical system. By modeling the lens assembly virtually, the system can measure and analyze optical characteristics without physically manipulating the actual lens components. This copying approach enables repeated measurements and alignments using the same virtual model, ensuring consistency while simplifying the physical alignment process.
2Manufacturing precision
If lenses are tested after assembly, then assembly variations are detected, but production time increases due to rework
Solution Approach 1:
The patent performs alignment measurements and optimizations before the final assembly step. By using the simulated lens assembly to pre-determine optimal alignment parameters, the system can prepare alignment instructions in advance. This preliminary action allows the actual lens assembly to be performed more quickly and accurately, reducing the need for rework and increasing production throughput while maintaining high precision.
Solution Approach 2:
The patent implements a feedback mechanism where optical characteristics measured during the simulated alignment process are used to adjust and optimize the actual lens assembly parameters. The system continuously compares measured performance against target specifications and automatically adjusts alignment parameters, providing real-time feedback that ensures precision without requiring time-consuming rework cycles.
3Measurement precision
If multiple alignment checks are performed, then lens centration is improved, but the test process becomes more time-consuming
Solution Approach 1:
The patent uses a simulated lens assembly that can be measured multiple times without physical constraints. The virtual model allows for rapid iterative measurements of optical characteristics and alignment parameters. By copying the lens behavior in a digital environment, the system can perform numerous alignment checks and optimizations in the time it would take for a single physical measurement, dramatically reducing test time while maintaining high measurement precision.
Solution Approach 2:
The patent implements periodic or iterative measurement cycles using the simulated lens assembly. Instead of performing all alignment checks sequentially in a time-consuming manner, the system uses the virtual model to rapidly cycle through multiple measurement and optimization iterations. This periodic action in the simulation space translates to faster overall alignment process completion while achieving the same level of precision.
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
Enhances MTF performance by precisely aligning lens centration vectors, reducing scrap rates and ensuring consistent camera assembly quality, thereby improving production output and reducing waste.
Implementation Method 1
variable focal length phased metalens
Implementation Method 2
lens elements of each of the rings is configured to provide a different focus capability
Data Source
AI summary
Described is camera focusing including lens centration estimation using variable focal length phased metalenses. Camera modular alignment and test (CMAT) equipment checks the modular transfer function (MTF) performance of lenses and an image sensor. The CMAT equipment positions a variable focal length phased metalens between the lenses and the image sensor. The metalens includes multiple segments that provide a variable focus depending on distance and angle from boresight of the image sensor. By measuring optical characteristics of the lenses at two opposing segments of the metalens, defocusing effects and a lens centration tilt vector can be computed. Repositioning the lenses to align the centration tilt vector with the boresight of the image sensor improves the MTF performance. A final camera assembly with lenses in precise alignment with the image sensor can be produced, which may improve production output by increasing pass rate at an end of line tester.