Convex Screen Optical Filter for Accurate Smoke Detector Testing
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Solution Overview
Problem
Existing optical filters for smoke detectors have a flat surface facing the light transmitter, causing direct light reflection that interferes with the testing accuracy and reliability of infrared beam smoke detectors.
Innovation Solution
An optical filter with a screen composed of wires, where at least one side facing the light transmitter is convex, scattering light reflections to prevent interference with the light receiver, and optionally supported by a frame or handle for ease of use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat optical filter is used to block light, then the light transmission is simple and the structure is simple, but direct light reflection occurs that interferes with testing accuracy
Solution Approach 1:
The patent applies curvature to the optical filter surface by adding convex protrusions or making the entire surface convex. This curved surface scatters direct reflected light away from the light receiver, preventing interference with the testing process while maintaining manufacturing feasibility through molding or coating techniques.
2Device complexity
If a flat optical filter is used, then the device structure is simple, but light reflection interferes with the light receiver
Solution Approach 1:
The convex surface design transforms the flat reflective surface into a curved one that scatters reflected light in multiple directions. This eliminates the harmful direct reflection path to the light receiver while adding only minimal structural complexity through surface profiling.
Solution Approach 2:
The optical filter introduces asymmetric convex protrusions or uneven surface features that disrupt the symmetric reflection path. This asymmetric geometry ensures that reflected light is scattered away from the light receiver position, which is located at a specific angle relative to the incident light.
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
The convex design of the optical filter ensures accurate testing of smoke detectors by eliminating direct light reflections, enhancing test reliability and ensuring proper functionality assessment.
Implementation Method 1
the screen has a first side and a second side opposite to each other; wherein, during testing, the optical filter is arranged in both the light path from the light transmitter to the light reflector and the light path from the light reflector to the light receiver, where at least the side of the wires of the screen facing the light transmitter of the smoke detector is convex so as to attenuate or eliminate light directly reflected back to the light receiver by the optical filter
Data Source
AI summary
The present application provides an optical filter, and a test assembly and method for a smoke detector. The optical filter comprises: a support; and a screen supported by the support, wherein the screen is composed of wires and mesh holes are defined between the wires, and the screen has a first side and a second side opposite to each other; wherein, the smoke detector comprises a light transmitter and a light receiver arranged in vicinity and an light reflector arranged opposite to the light transmitter and the light receiver, such that light emitted by the light transmitter is reflected to the light receiver via the light reflector; and wherein, during testing, the optical filter is arranged in both the light path from the light transmitter to the light reflector and the light path from the light reflector to the light receiver.