Dual LED Optical Interrupter Cost Reduction
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Solution Overview
Problem
Optical interruption sensors, or photo-interrupters, face high costs due to the use of light emitting diodes (LEDs) and phototransistors, limiting their application in various products.
Innovation Solution
The use of two identical light emitting diodes as both the transmitter and receiver, along with integrated circuitry for biasing and detection, reduces costs and simplifies manufacturing by allowing flexible adjustment of switching thresholds and operation across different voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light emitting diode and phototransistor pair is used in the optical interruption sensor, then the sensor can detect light blockage effectively, but the cost of the sensor increases
Solution Approach 1:
The patent replaces the expensive phototransistor with a light emitting diode, using a cheaper component (LED) to perform the detection function. This substitution directly reduces component cost while maintaining the optical interruption detection capability, as the LED can function as both transmitter and receiver when appropriately configured
Solution Approach 2:
The patent makes the light emitting diode perform multiple functions: it serves as both the light transmitter and the light receiver (photodetector). By configuring the LED to operate in both emission and detection modes, the system eliminates the need for separate phototransistor components, reducing part count and manufacturing cost while maintaining detection reliability
2Reliability
If different types of light emitting diodes are used for transmitter and receiver, then optimal performance can be achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent uses identical or similar light emitting diodes for both transmission and reception functions. This homogeneity in component selection simplifies the bill of materials, reduces manufacturing complexity, and enables economies of scale in procurement and assembly, while the LEDs are configured to perform different roles (transmitter vs. detector) based on their orientation and circuit connection
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 approach results in a low-cost, efficient, and versatile optical-interrupter capable of detecting light blockages with improved conversion efficiencies and reduced assembly complexity, enabling wider product integration.
Implementation Method 1
The solid-state light transmitter and solid-state light receiver are both light emitting diodes
Implementation Method 2
a detector circuit providing an electrical output (typically a binary signal) indicating whether the light beam is blocked or unblocked based on a pre-established threshold applied to an electrical signal from the light receiver
Data Source
AI summary
An optical-interrupter provides a mechanically integrated electric light source and electric light sensor positioned across a gap to transmit a light beam across the gap that may be interrupted with an opaque vane. The optical-interrupter uses conventional LEDs for both the light source and a light receiver. An integrated circuit comparator may be used to provide an adjustable threshold for the determination of whether the light beam is blocked.