Optical Module Substrate Thickness Adjustment for Focal Length Correction

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Solution Overview

Problem

Manufacturing irregularities in optical devices, such as variations in focal lengths of lens elements, lead to inferior image quality due to misalignment of focal planes with image sensor planes.

Innovation Solution

The method involves fabricating optical devices by mounting singulated lens systems over a substrate, adjusting the substrate thickness through micro-machining or adding layers to correct focal length variations, and subsequently separating the substrate into optical modules, allowing for pre-testing of lens stacks before final assembly to ensure compliance with specified requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If wafer-scale manufacturing is used to produce multiple lens elements, then productivity increases, but manufacturing precision deteriorates due to focal length variations

Engineering Contradiction:

ImproveproductivityVSAvoidfocal length precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by varying the substrate thickness at different locations to compensate for focal length variations. Specifically, the substrate is made thinner in regions where lens elements have longer focal lengths and thicker in regions where lens elements have shorter focal lengths, thereby equalizing the effective focal lengths of all lens elements across the wafer while maintaining high productivity through wafer-scale manufacturing

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameter of substrate thickness to correct focal length variations. By controlling the substrate thickness distribution across the wafer, the patent compensates for manufacturing variations in lens elements, achieving consistent effective focal lengths without sacrificing the productivity benefits of wafer-scale manufacturing

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If substrate thickness is adjusted to correct focal length variations, then manufacturing precision improves, but device complexity increases

Engineering Contradiction:

Improvefocal length precisionVSAvoidsubstrate structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the focal length correction function into the substrate itself by varying its thickness, rather than adding separate correction elements or mechanisms. This integration approach corrects focal length variations while avoiding additional device complexity, as the substrate simultaneously serves as both the mounting platform and the focal length adjustment mechanism

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10373996B2Optical modules including focal length adjustment and fabrication of the optical modules

Publication Date: 2019.08.06 AMS OSRAM ASIA PACIFIC PTE LTD

AI summary

Fabricating optical devices can include mounting a plurality of singulated lens systems over a substrate, adjusting a thickness of the substrate below at least some of the lens systems to provide respective focal length corrections for the lens systems, and subsequently separating the substrate into a plurality of optical modules, each of which includes one of the lens systems mounted over a portion of the substrate. Adjusting a thickness of the substrate can include, for example, micro-machining the substrate to form respective holes below at least some of the lens systems or adding one or more layers below at least some of the lens systems so as to correct for variations in the focal lengths of the lens systems.