Image Sensor Module Autofocus Spacer Mechanism

Solution Overview

Problem

High-quality compact cameras, especially those with autofocus, face challenges in active alignment due to slow and costly voice coil motor (VCM) adjustments, which are required for precise lens positioning relative to the image sensor, often resulting in tilt issues and increased z height.

Innovation Solution

The image sensor module incorporates a spacer system with an actuator to adjust the optical sub-assembly within the lens barrel housing, allowing for precise positioning and reducing tilt, while maintaining a small form factor, using electromagnetic or MEMS actuators and spacers that are directly attached to the image sensor or housing to facilitate autofocus control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If VCM is used for active alignment to compensate for tilt, then alignment precision is improved, but manufacturing time and cost increase

Engineering Contradiction:

Improvealignment precisionVSAvoidmanufacturing time

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The spacer is designed with pre-determined thickness and is attached to the lens barrel sub-assembly before active alignment. This preliminary positioning action establishes a fixed reference distance between the lens barrel and image sensor, eliminating the need for time-consuming VCM-based distance adjustment during active alignment.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The spacer acts as an intermediary component between the lens barrel sub-assembly and the image sensor. It provides a fixed mechanical reference that mediates the positioning relationship, allowing tilt compensation without requiring the VCM to adjust both distance and orientation simultaneously.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If VCM is used for active alignment to compensate for tilt, then alignment precision is improved, but manufacturing cost increases

Engineering Contradiction:

Improvealignment precisionVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The spacer is designed with pre-determined thickness and is attached to the lens barrel sub-assembly before active alignment. This preliminary positioning action establishes a fixed reference distance between the lens barrel and image sensor, eliminating the need for time-consuming VCM-based distance adjustment during active alignment.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The spacer acts as an intermediary component between the lens barrel sub-assembly and the image sensor. It provides a fixed mechanical reference that mediates the positioning relationship, allowing tilt compensation without requiring the VCM to adjust both distance and orientation simultaneously.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If traditional autofocus positioning is used, then focusing control is achieved, but z height increases

Engineering Contradiction:

Improveautofocus controlVSAvoidz height

Core Design Contradiction:

Ease of operationVSLength of stationary object

Solution Approach 1:

The optical sub-assembly is nested inside the lens barrel housing, which itself is positioned relative to the image sensor using the spacer. This nested arrangement allows the optical components to be compactly organized within the constrained z-space defined by the spacer thickness.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The spacer establishes the final z-height position of the lens barrel sub-assembly relative to the image sensor before the optical sub-assembly is installed. This preliminary positioning constrains the overall z-height while still allowing the actuator to provide the necessary travel range for autofocus operation.

Inventive Principle:

Principle #10Preliminary action

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 solution enables ultra-precise and stable autofocus control, reducing tilt and z height, thereby improving focusing and image stabilization in compact camera modules, while maintaining a small footprint and reducing manufacturing costs.

Implementation Method 1

an actuator operable to adjust a position of the optical sub-assembly inside the lens barrel housing

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

a voice coil motor (VCM) is provided to facilitate the autofocus control

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentUS10890733B2Image sensor module with auto focus control

Publication Date: 2021.01.12 AMS OSRAM ASIA PACIFIC PTE LTD

AI summary

The present disclosure describes image sensor modules that can include auto focus control. The modules also include features that can help reduce or eliminate tilt of the module's optical sub-assembly with respect to the plane of the image sensor. In some instances, the modules include features to facilitate highly precise positioning of the optical sub-assembly, and also can result in modules having a very small z height.