Optical Sensor Dual-Gap Bonding for Stable Axis Alignment
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Solution Overview
Problem
Existing optical sensors face challenges in accurately adjusting the optical axis of the lens module due to variations in adhesive gap sizes and potential exposure of uncured adhesive to UV light, leading to reduced fixing strength and positional deviation.
Innovation Solution
The use of ultraviolet and heat-curable adhesive is applied in both the projector and receiver units, with a main gap and a wider sub-gap design, allowing precuring of the adhesive in the sub-gap before full curing to ensure accurate optical axis alignment and fixing strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single gap is used for adhesive application, then the manufacturing process is simple, but the adhesive may be exposed to UV light causing reduced fixing strength
Solution Approach 1:
The gap between the light source module and lens module is divided into two distinct regions: a first gap and a second gap. The adhesive is applied to both gaps, with the second gap positioned such that it prevents UV light from reaching the adhesive in the first gap. This segmentation allows the adhesive to be protected from UV exposure while maintaining a straightforward manufacturing process.
2Manufacturing precision
If the adhesive gap is made wider to ensure complete filling, then the adhesive spans both bonding surfaces reliably, but the positional precision of optical axis alignment decreases
Solution Approach 1:
Different regions of the gap are assigned different functions: the first gap is optimized for precise optical axis alignment with smaller dimensions, while the second gap is designed to be wider to ensure complete adhesive filling and protect the adhesive from UV light. This local differentiation allows each region to optimize for its specific purpose without compromising the other.
3Productivity
If UV curable adhesive is used for quick curing, then the manufacturing cycle is shortened, but the adhesive may cure prematurely or be affected by UV exposure causing positional deviation
Solution Approach 1:
The adhesive is applied in a state where it can be cured by UV light, but the curing process is controlled to occur only after the optical components are properly positioned. The second gap is designed to shield the adhesive in the first gap from UV light during assembly, preventing premature curing. The adhesive is then cured in a controlled manner after positioning is complete, ensuring both quick curing and positional stability.
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 ensures precise optical axis adjustment and robust fixing strength by precuring the adhesive in the sub-gap, minimizing positional deviation and enhancing the stability of the optical sensor components.
Implementation Method 1
The projector adhesive may be ultraviolet and heat curable and may be interposed between a projector bonding surface of the projector light source module and a projector bonding surface of the projector lens module
Implementation Method 2
The projector adhesive may be ultraviolet and heat curable
Data Source
AI summary
An optical sensor includes: a projector light source module, a projector lens module and a projector adhesive that is ultraviolet and heat curable and is interposed between a projector bonding surface of the projector light source module and a projector bonding surface of the projector lens module which are opposed to each other in a light projecting direction of a projection beam generated from the projector light source module. The projector bonding surfaces of the projector light source module and the projector lens module form therebetween: a projector main gap that is filled with the projector adhesive; and a projector sub-gap that has a width larger than a width of the projector main gap in the light projecting direction and opens toward a radially outer side around the projected light optical axis. The projector adhesive is filled continuously from the projector main gap to the projector sub-gap.