Integrated Plastic Lens Holder for Optical Module Alignment
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Solution Overview
Problem
Existing optical modules for optical fiber communication face inefficiencies in the aligning operation during assembly, making the process cumbersome and prone to errors due to the separation of optical components, which complicates the alignment of optical axes.
Innovation Solution
An optical module design featuring a holder with an integrated aspherical lens and cylindrical portion, where the lens has a smoothly curved surface projecting towards the photoelectric transfer element package, allowing for optical coupling without the need for separate alignment of optical axes, and using a plastic holder with a metal cap to maintain focal point coincidence despite temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the photoelectric transfer element package, spherical lens and optical fiber of the ferrule are separated, then each component can be manufactured independently with standard processes, but the aligning operation becomes complex and operation efficiency decreases
Solution Approach 1:
The lens and holder are integrated into a single molded structure, eliminating the need for separate alignment of the lens with the holder. The lens is directly formed within the holder body during the molding process, so that the lens position and orientation are automatically determined by the mold geometry, eliminating complex alignment operations while maintaining independent manufacturability of the integrated assembly
2Device complexity
If the lens and holder are made of plastic and integrated, then the number of parts is reduced and assembly is simplified, but temperature variations may cause focal point displacement affecting optical coupling
Solution Approach 1:
The holder structure incorporates a specifically designed lens mounting portion with controlled thermal expansion characteristics. The geometry of the mounting portion (including its length and cross-sectional dimensions) is optimized so that the thermal expansion of the plastic holder compensates for the thermal changes in the lens focal length, maintaining focal point coincidence across temperature variations
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 design simplifies the assembly process, enhances optical coupling efficiency, reduces the number of parts, and maintains focal point alignment across temperature variations, improving productivity and optical communication efficiency.
Implementation Method 1
a lens, arranged between the optical fiber mounting hole and cylindrical portion of the holder, for causing the ferrule to be optically coupled with the photoelectric transfer element package
Implementation Method 2
the lens having a smoothly curved surface which projects toward the photoelectric transfer element package
Implementation Method 3
the variation (ΔL) of an axial length (L) from the vertex of the lens to the open end face of the cylindrical portion in accordance with temperature change
Data Source
AI summary
An optical module capable of preventing the efficiency of optical coupling from deteriorating even if temperature varies. The optical module 1 has a holder 2 and an aspherical lens 11, which are formed of a plastic so as to be integrated with each other. The holder 2 has a cylindrical portion 8 which engages a photoelectric transfer element package 3. The photoelectric transfer element package 3 has a flange portion 15 which butts the open end face 16 of the cylindrical portion 8. The flange portion 15 is bonded to the open end face 16 of the cylindrical portion 16, and a gap is formed between the outer peripheral surface 18 of the cap 12 of the photoelectric transfer element package 3 and the inner peripheral surface of the cylindrical portion 8.