Smoke Detector Optical Cap for Direct Light Blocking
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Solution Overview
Problem
Existing smoke detectors face challenges in effectively blocking direct line of sight between light emitters and receivers, leading to saturation and inaccurate readings due to ambient and nuisance light, which requires significant physical space and cumbersome manufacturing and calibration.
Innovation Solution
A cap with an enclosure of predefined profile is fitted over the light emitter and receiver, featuring a strip that blocks direct line of sight while allowing light reflection from smoke and a predefined clean air signal, made of flexible or infrared light-absorbing material, and optionally includes a coupling element for secure fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing chamber designs block nuisance light, then light saturation is reduced, but physical space required increases and manufacturing complexity increases
Solution Approach 1:
The invention divides the light-blocking function into a separate removable cap component rather than integrating it into the chamber structure. This segmentation allows the cap to be manufactured independently with precise optical blocking features (strip of predefined width) while keeping the main chamber design simple and straightforward to manufacture.
Solution Approach 2:
The cap acts as an intermediary component between the light emitter and light receiver, providing the light-blocking function without requiring modifications to the chamber structure. This intermediary approach simplifies manufacturing by decoupling the light-blocking requirement from the chamber fabrication process.
2Measurement precision
If direct line of sight is blocked between light emitter and receiver, then baseline light is reduced, but physical space and manufacturing steps increase
Solution Approach 1:
The light-blocking function is segmented into a separate cap component that can be manufactured independently using simple processes. The cap's strip of predefined width is designed to block direct line of sight when fitted over the lens, achieving baseline light control without complex integrated chamber designs.
Solution Approach 2:
Instead of blocking light through complex chamber geometry, the invention uses a simple cap that fits over the lens assembly. This inverted approach places the blocking element at the optical interface rather than trying to achieve blocking through chamber shape, significantly simplifying manufacturing.
3Measurement precision
If light receiver is highly sensitive to detect smoke, then detection capability improves, but susceptibility to ambient and nuisance light increases
Solution Approach 1:
The cap serves as an intermediary optical element that selectively blocks harmful direct light from reaching the sensitive receiver while allowing scattered smoke light to pass. The strip of predefined width is positioned to interrupt direct line of sight between emitter and receiver, protecting the sensitive detector from saturation by ambient and nuisance light.
Solution Approach 2:
The cap provides localized light-blocking properties at the critical interface where direct light would enter the receiver. The strip of predefined width is strategically positioned to block only the direct light path while leaving other areas open to allow scattered smoke light to reach the sensitive receiver, thus protecting against harmful light without compromising detection sensitivity.
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 solution reduces material and manufacturing costs, enhances smoke detection accuracy, and increases chamber space for smoke entry, making the detector compact, efficient, and cost-effective.
Implementation Method 1
The strip upon fitting of the cap over any of the light emitter and the light receiver, blocks a direct line of sight between the light emitter and the light receiver
Implementation Method 2
The smoke detector detects the presence and amount of smoke in the chamber when light (photons) emitted by the light emitter is scattered by the smoke particles and the scattered photons are sensed by the light receiver
Implementation Method 3
Light emitter(s), such as Light Emitting Diodes (LEDs)
Implementation Method 4
light receiver(s), such as a Photo Diodes (PDs)
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A cap for a light emitter and/or light receiver of a smoke detector for eliminating a direct line of sight between the light emitter and the light receiver is disclosed. The cap comprises an enclosure of a predefined profile having a predetermined open area at a predetermined position on the enclosure, which is adapted to be removably fitted over one or more of the light emitter and/or the light receiver. The cap upon fitting over any of the light emitter and the light receiver, the cap blocks a direct line of sight between the light emitter and the light receiver and allows the light receiver to receive only the light being reflected by smoke and a predefined amount of clean air signal present within the smoke detector.