Active OIS Alignment via 45-Degree Light Reflection

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Solution Overview

Problem

Conventional alignment apparatuses are unsuitable for folded camera modules with complex optical paths and optical image stabilizer (OIS) systems, leading to potential yield loss due to initial tilting errors between the OIS module and the image sensor, which cannot be fully compensated by the limited tilting correction motor travel range.

Innovation Solution

A method involving the use of active alignment systems combined with detection or inspection devices to align lens elements, specifically moving the first lens module relative to the image sensor until the reflective surface forms a 45-degree inclination angle with incident light, ensuring normal projection onto the image sensor plane, and using holders capable of six degrees of freedom adjustments to correct tilting errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional alignment apparatus is used for folded camera modules, then the alignment process becomes unsuitable for complex optical paths, but using active alignment with additional detection devices increases measurement precision and manufacturing precision

Engineering Contradiction:

Improvealignment precision of OIS moduleVSAvoidcomplexity of alignment system

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

A light beam serving as an intermediary reference is introduced to establish a precise alignment reference for the OIS module. The light beam reflects off the OIS lens element and prism, enabling indirect measurement of alignment status without requiring direct contact or complex mechanical interfaces between the alignment apparatus and the optical components

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces conventional mechanical alignment methods with an optical-based active alignment system. Instead of using mechanical fixtures and direct physical contact for alignment, the system uses light beams, reflective surfaces, and optical detection to achieve precise alignment of the OIS module with the image sensor

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If passive bonding process is used without prior alignment, then the assembly process is simpler, but the initial tilting error exceeds compensation capability

Engineering Contradiction:

Improvesimplicity of assembly processVSAvoidalignment accuracy of OIS lens element

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent performs preliminary active alignment of the OIS module with the image sensor before the final bonding process. The alignment apparatus adjusts the OIS module to the correct position and orientation while it is still movable, ensuring that when bonding occurs, the components are already precisely aligned. This preliminary action prevents the need for complex post-bonding adjustments

Inventive Principle:

Principle #10Preliminary action

3Volume of moving object

If limited tilting correction motor travel range is used, then the device structure is more compact, but it cannot fully compensate for large initial tilting errors

Engineering Contradiction:

Improvecompactness of OIS moduleVSAvoidcompensation capability for alignment errors

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The alignment apparatus performs preliminary alignment of the OIS module to minimize initial tilting errors before bonding. By ensuring the OIS module is pre-aligned to within a small error margin, the limited travel range of the tilting correction motor becomes sufficient to compensate for the reduced initial errors, maintaining reliability while preserving compactness

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 method enhances production yield by accurately aligning the OIS module with the image sensor, ensuring correct viewing direction and image quality, even with initial tilting errors, by utilizing active alignment and additional inspection tools to compensate for mechanical limitations.

Implementation Method 1

receiving an incident light along a first optical path with a reflective surface of the first lens element and projecting the incident light along a second optical path perpendicular to the first optical path

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS11283978B1Aligning lens elements in a lens module relative to an image sensor

Publication Date: 2022.03.22 ASMPT SINGAPORE PTE LTD

AI summary

Before fixing first and second lens modules to an image sensor to form an assembled camera module, the first lens module is held while electrical signals are provided to a first lens element comprised in the first lens module to drive the first lens element to move. An incident light is received along a first optical path and a reflective surface of the first lens element projects the incident light along a second optical path perpendicular to the first optical path such that the incident light is projected through the second lens module along the second optical path onto the image sensor. The first lens module and first lens element are moved relative to the image sensor until the reflective surface forms an inclination angle of 45 degrees with respect to the incident light, so that the incident light is projected normally onto an image plane of the image sensor.