Camera Module Sub-Lens Assembly Alignment

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Solution Overview

Problem

Current camera module manufacturing faces challenges in achieving high resolution and large aperture due to assembly deviations, refractive index changes, and limited precision control, leading to low yield and high failure rates, as existing active alignment processes are insufficient to compensate for aberrations affecting imaging quality.

Innovation Solution

A method for adjusting the relative position of sub-lens assemblies in multiple degrees of freedom, including translation, rotation, and angle adjustments, to improve the actual measured resolution and reduce image plane inclination, using non-active alignment techniques such as mechanical alignment, and bonding or welding processes to connect the assemblies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If active alignment process is used to compensate for photosensitive chip inclination, then module assembly yield improves, but resolution cannot reach specification due to optical system aberrations

Engineering Contradiction:
Improvemodule assembly yieldVSAvoidimaging resolution
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The optical system is divided into multiple independent lens assemblies (first lens assembly, second lens assembly, etc.), each with its own adjustable mounting structure. This segmentation allows independent adjustment of each lens assembly's position and angle, enabling precise compensation for optical aberrations while maintaining high assembly yield.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lens assemblies are mounted on adjustable structures that allow dynamic adjustment of position and orientation during assembly. The mounting structures include adjustable arms, clamps, and positioning mechanisms that enable real-time modification of lens assembly angles and positions to compensate for optical system aberrations and achieve specification-compliant resolution.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If dimensional tolerances of elements are controlled and lens turning is performed, then resolution increases, but manufacturing difficulty and cost increase significantly

Engineering Contradiction:
ImproveresolutionVSAvoidmanufacturing difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Instead of attempting to manufacture lens elements with extremely tight tolerances (1 μm eccentricity control), the invention inverts the approach by using adjustable mounting structures that allow post-assembly correction of alignment errors. This enables resolution improvement without requiring prohibitively difficult and expensive precision manufacturing processes.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention changes the approach from controlling manufacturing parameters (dimensional tolerances, lens turning) to adjusting operational parameters (mounting position, angle, and orientation during assembly). This allows resolution optimization through adjustable parameters rather than relying on difficult-to-control manufacturing parameters.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If multiple lens assemblies are used to achieve high resolution, then imaging quality improves, but assembly deviations accumulate and reduce yield

Engineering Contradiction:
Improveimaging qualityVSAvoidassembly yield
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

Each lens assembly is mounted on an adjustable structure that enables dynamic correction of assembly deviations. The adjustable mounting structures allow independent positioning and angular adjustment of each lens assembly, compensating for cumulative deviations and maintaining high imaging quality with improved assembly yield.

Inventive Principle:
Principle #15Dynamics

4Manufacturing precision

If feedback period is extended in assembly process, then more adjustments can be made, but process capability index (CPK) decreases and failure rate increases

Engineering Contradiction:
Improveadjustment capabilityVSAvoidprocess capability index
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The adjustable mounting structures are designed and prepared in advance, allowing quick adjustment of lens assemblies during the assembly process. This preliminary preparation of adjustment mechanisms enables rapid corrections without extending the feedback period, maintaining high process capability index while providing adequate adjustment capability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3684044B1Camera module and assembly method therefor
Publication Date: 2024.10.23 NINGBO SUNNY OPOTECH CO LTD
  • EP3684044B1 patent drawingFigure 1~2
  • EP3684044B1 patent drawingFigure 3~6
  • EP3684044B1 patent drawingFigure 7~8

AI summary

The present invention provides a method for assembling a camera module, including: preparing a first sub-lens assembly and a second sub-assembly, wherein the second sub-assembly includes a second sub-lens assembly and a photosensitive assembly fixed together; arranging the first sub-lens assembly on an optical axis of the second sub-lens assembly to form an optical system capable of imaging; adjusting a relative position of the first sub-lens assembly with respect to the second sub-lens assembly, so as to increase an actual measured resolution of imaging of the optical system, obtained by using the photosensitive element, to a first threshold, and decrease an actual measured image plane inclination obtained by using the photosensitive element to a second threshold; and connecting the first sub-lens assembly and the second sub-lens assembly. The present invention further provides a corresponding camera module. The present invention can improve the resolution of the camera module; can improve the capability of process index of mass production of the camera module; can reduce the overall costs of the optical imaging lens assembly and module; and can reduce the failure rate and the production costs, and improve the imaging quality.