Optical Sensor Sealing Resin Prevents Adhesive Infiltration
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Solution Overview
Problem
Existing optical sensors face issues with adhesive infiltration into the optical path, which can block light and reduce detection accuracy, and insufficient adhesive application leading to loose fixation and oil leakage.
Innovation Solution
An optical sensor design that includes a light emitting element and a light receiving element with an optical path through an oil infiltrating space, where the substrate and associated components are sealed within an accommodation space by a sealing resin to prevent adhesive interference and ensure reliable support without blocking the optical path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an excessive amount of adhesive is applied to fix the gap forming member to the support member, then the fixation strength is improved, but the adhesive overflows into the first space or second space and blocks the optical path, deteriorating detection accuracy
Solution Approach 1:
A sealing member (resin or O-ring) is introduced as an intermediary between the adhesive and the optical path spaces. The sealing member is applied to the peripheral surface of the gap forming member, creating a barrier that prevents adhesive from overflowing into the first and second spaces while allowing the adhesive to adequately bond the gap forming member to the support member.
2Measurement precision
If an insufficient amount of adhesive is applied to fix the gap forming member to the support member, then the optical path remains clear, but the fixation strength becomes insufficient and lubricating oil leaks from between the gap forming member and support member
Solution Approach 1:
The sealing member acts as a mediator that decouples the relationship between adhesive quantity and adhesive overflow. This allows the adhesive amount to be optimized for strong fixation without the risk of overflowing into the optical path, as the sealing member contains any excess adhesive.
Solution Approach 2:
The sealing member can be implemented as a flexible O-ring or resin layer that conformally seals the peripheral surface of the gap forming member. This flexible sealing structure effectively prevents adhesive and lubricating oil from leaking into the optical path spaces while maintaining the integrity of the optical components.
3Object-affected harmful factors
If a groove is formed on the support member to prevent adhesive infiltration, then adhesive overflow is reduced, but the structural complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of forming a groove on the support member, the sealing member is applied locally to the peripheral surface of the gap forming member. This localized sealing approach achieves the same protective function without requiring complex groove structures, thereby simplifying the overall device design and reducing manufacturing complexity.
Data Source
AI summary
An optical sensor is provided, in which members forming an optical path can be reliably supported without blocking the optical path extending from a light source to a light receiver. An optical sensor includes a light source configured to emit light, and a light receiver configured to receive the light emitted from the light source. An optical path extending from the light source to the light receiver extends through an oil infiltrating space into which oil infiltrates. The optical sensor further includes: a substrate on which the light source is mounted; a substrate on which the light receiver is mounted; a fixing member including an accommodation space in which the substrates are accommodated; and a sealing resin contained in the accommodation space and sealing the substrate.