Customizable Spacer Optical Modules for Focal Length and Tilt Adjustment
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Solution Overview
Problem
Manufacturing irregularities in optical modules for array cameras, such as variations in focal lengths and thermal expansion, lead to inferior image quality, while adhesive issues cause tilt and potential contamination of image sensors.
Innovation Solution
The use of customized spacers with varying heights and edge features to adjust focal lengths, combined with a single transparent cover and protective hood, helps stabilize the optical channels and prevent adhesive migration, along with wafer-level fabrication for multiple module production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is used to attach the optical assembly to the substrate, then the optical components are secured in place, but the adhesive may migrate to the active portion of the image sensor, rendering the module unusable
Solution Approach 1:
The optical assembly is divided into separate components: the lens stack, the transparent cover, and the spacer. This segmentation allows the adhesive to be applied only to the spacer's adhesion edge, which is positioned away from the active sensor area, thus securing the assembly without risking adhesive migration to the image sensor.
Solution Approach 2:
The spacer acts as an intermediary component between the optical assembly and the substrate. It provides a dedicated adhesion edge for adhesive attachment while maintaining a physical barrier that prevents adhesive from reaching the active portion of the image sensor.
2Stability of the object's composition
If adhesive is applied to attach the optical assembly, then the components are fixed, but uneven adhesive distribution causes tilt in the optical assembly, reducing image quality
Solution Approach 1:
The optical assembly is segmented into the lens stack, transparent cover, and spacer components. This allows the adhesive to be applied only to the spacer's adhesion edge, which is designed to distribute adhesive evenly. The segmentation isolates the adhesive application area from the optical path, preventing tilt caused by uneven adhesive distribution.
Solution Approach 2:
The spacer is designed with a specific adhesion edge that has localized adhesive application properties. This edge is positioned and shaped to ensure even adhesive distribution, while the rest of the spacer maintains its structural function. The local quality of the adhesion edge ensures stable attachment without causing optical assembly tilt.
3Stability of the object's composition
If a single transparent cover is used over all optical channels, then thermal expansion is reduced and structural stability is improved, but the overall device height increases
Solution Approach 1:
The optical module is segmented into functional layers: the lens stack, the transparent cover, and the spacer with adhesion edge. This segmentation allows the single transparent cover to provide thermal stability across all optical channels while the spacer's adhesion edge design minimizes the overall height by optimizing the attachment geometry.
4Manufacturing precision
If the spacer has customized heights for different optical channels, then focal length variations are corrected, but the manufacturing complexity increases
Solution Approach 1:
The spacer is designed with local quality variations: customized heights at different optical channel locations and a specific adhesion edge configuration. This allows precise focal length correction for each channel while maintaining a relatively simple overall spacer structure that can be manufactured using standard techniques.
Solution Approach 2:
The spacer's physical parameters (height, adhesion edge position) are optimized to correct focal length variations. By adjusting these parameters during design, the spacer compensates for manufacturing deviations in the optical channels while remaining manufacturable.
Data Source
AI summary
An optical module comprising: a plurality of active optoelectronic components each one mounted on a respective printed circuit board (PCB), wherein each active optoelectronic component is associated with a respective different optical channel; a plurality of optical assemblies, each one is substantially aligned over a different respective optical channel; and a spacer separating the active optoelectronic components and PCBs from the optical assemblies, wherein the optical assemblies are attached by adhesive directly to an optical assembly-side surface of the spacer. A first active optoelectronic component is separated, by the spacer, from a first optical assembly by a first distance and a second active optoelectronic component is separated, by the spacer, from a second optical assembly by a different second distance. Also contemplated is a method for fabricating an optical module that comprises: modifying a height of one or more extensions on a spacer to adjust for at least one of a focal length or tilt of at least one optical channel.