Proximity Sensor Cup Design for Cross Talk Reduction
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Solution Overview
Problem
Transmitter/receiver type proximity sensors face accuracy issues due to 'cross talk' caused by electromagnetic radiation being transmitted directly to the receiver without reflection off a target object, resulting in internal reflection and refraction within the sensor itself.
Innovation Solution
The design incorporates a compact printed circuit board with reflector cups and a radiation attenuating layer to minimize cross talk, featuring a small size and reduced process steps for production, with a transmitter and receiver mounted in separate cups and covered by encapsulants to ensure radiation is focused and only reflected radiation reaches the receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a transmitter and receiver are positioned adjacent to each other in a compact configuration, then the sensor size is reduced, but cross talk between transmitter and receiver increases
Solution Approach 1:
A reflector cup positioned between the transmitter and receiver acts as an intermediary structure to block and redirect electromagnetic radiation. The cup prevents direct radiation paths from transmitter to receiver while allowing reflected radiation from target objects to reach the receiver, thereby eliminating cross talk in compact configurations.
Solution Approach 2:
The interior surface of the reflector cup is made selectively reflective to electromagnetic radiation in the operating wavelength range. This localized reflective property directs radiation away from the receiver when no target object is present, while still allowing the receiver to detect reflected radiation from actual target objects.
2Reliability
If internal reflection and refraction are minimized through structural design, then cross talk is reduced, but device complexity increases
Solution Approach 1:
The reflector cup is integrated directly into the housing structure of the proximity sensor, merging the radiation-blocking function with the structural framework. This eliminates the need for separate internal shielding components while achieving the same cross talk reduction effect.
Solution Approach 2:
The reflector cup serves multiple functions simultaneously: it acts as a structural support element, a radiation blocking barrier, and a radiation directing component. This multi-functionality reduces the need for additional dedicated cross talk suppression components.
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 configuration significantly reduces cross talk, enhancing the accuracy of the proximity sensor by ensuring only reflected radiation is detected, while also reducing production costs and complexity.
Implementation Method 1
a transmitter which transmits electromagnetic radiation of a predetermined wavelength range
Implementation Method 2
IR radiation which strikes a nearby object and is reflected by the object back towards the transmitter and receiver
Implementation Method 3
a receiver which is adapted to receive electromagnetic radiation in the predetermined wavelength range and generate a signal indicative of the amount of such electromagnetic radiation that is received
Data Source
AI summary
A proximity sensor includes a printed circuit board (PCB); a first cup and a second cup embedded in the PCB; an electromagnetic radiation transmitter operably mounted in the first cup; and an electromagnetic radiation receiver operably mounted in the second cup.