Automated Camera Module Focusing via Defocus Metric Iteration

Solution Overview

Problem

Automated focusing of camera modules in compact electronic devices is inefficient, leading to increased production time and costs, particularly during the end-of-line assembly process, where achieving precise focusing quality is challenging due to the complexity of adjusting lens assemblies relative to imaging devices.

Innovation Solution

The implementation of a method that uses a test chart with reference markings to quantify focusing quality through a defocus metric, allowing iterative adjustments of the lens assembly's position until a satisfactory focus is achieved, utilizing a control unit and positioning mechanism to accurately align the lens assembly with the imaging device, enabling rapid and precise focusing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If automated focusing is implemented during end-of-line assembly, then focusing quality can be achieved, but production time and costs increase due to the complexity of adjusting lens assemblies

Engineering Contradiction:

Improvefocusing qualityVSAvoidproduction time

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The lens assembly is pre-positioned at a nominal focal length distance from the imaging device before final assembly. This preliminary positioning allows the majority of focusing adjustment to be done in advance, reducing the complexity and time required for automated focusing during end-of-line assembly.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex mechanical adjustment systems with a simplified positioning mechanism that uses a nominal focal length reference. Instead of implementing sophisticated automated focusing systems during assembly, the invention uses a predetermined mechanical position that achieves satisfactory focusing quality without requiring complex control systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If lens assembly position is adjusted during assembly, then focusing quality improves, but the complexity of the assembly process increases

Engineering Contradiction:

Improvefocusing qualityVSAvoidassembly process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The lens assembly is pre-positioned at a nominal focal length distance from the imaging device before final assembly. This preliminary positioning allows the majority of focusing adjustment to be done in advance, reducing the complexity and time required for automated focusing during end-of-line assembly.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses a nominal focal length as a reference parameter to simplify the focusing process. By establishing a predetermined distance based on the nominal focal length, the complex task of achieving precise focus is converted into a simpler positioning task with a clear target parameter, reducing assembly process complexity.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If lens assembly movement range is minimized, then optical center performance improves, but focusing adjustment capability is reduced

Engineering Contradiction:

Improveoptical center performanceVSAvoidfocusing adjustment capability

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The lens assembly is pre-positioned at a nominal focal length distance from the imaging device before final assembly. This preliminary positioning allows the majority of focusing adjustment to be done in advance, reducing the complexity and time required for automated focusing during end-of-line assembly.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses a nominal focal length as a reference model or copy of the ideal focus position. By replicating this predetermined position during assembly, the system achieves consistent optical center performance while minimizing the need for extensive movement ranges, as the reference position guides the final placement.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS9516302B1Automated focusing of a camera module in production

Publication Date: 2016.12.06 AMAZON TECH INC

AI summary

Embodiments of the disclosure permit automated focusing of a camera module during assembly. The camera module can include an imaging device and a lens assembly that is movably mounted to a housing of the camera module. In certain embodiments, the automated focusing can include iteratively imaging a fixed set of reference markings, and successively quantifying the focusing quality of the camera module based at least on a defocus metric defined as a difference between a current spacing and a calibrated spacing among two of the imaged reference markings. The magnitude and sign of the defocus metric can guide, respectively, a magnitude and direction of the movement of the lens assembly relative to the imaging device. After successive adjustments yield a desired focusing quality of the camera module, the lens assembly can be locked in position and can be further processed according to a suitable camera module integration flow.