Optoelectronic Sensor Back-Side Reference Receiver
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Solution Overview
Problem
Optical sensors face challenges in achieving error-free operation due to light interference between reference and measurement channels, particularly at short times of flight for detecting objects with small spacing, where traditional separation methods are inefficient and costly, and existing packages are limited in their ability to separate the channels effectively.
Innovation Solution
An optoelectronic sensor design where the semiconductor component is arranged on a circuit board with the reference light receiver illuminated by transmitted light through the side of the component, using optical elements to direct light to the reference receiver while preventing interference with the measurement receiver, allowing for improved optical separation between the channels without the need for separate chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the semiconductor component is made small to reduce construction space and costs, then the two optical surfaces or channels are disposed close to one another, but it becomes difficult or impossible to apply a barrier between the two channels
Solution Approach 1:
The patent transitions from attempting to separate channels in the planar dimension (which becomes impossible as component size decreases) to utilizing the depth dimension by illuminating the reference light receiver through the substrate from the circuit board side. This vertical separation approach allows optical channel isolation without requiring lateral barriers, thereby resolving the contradiction between small component size and barrier applicability
Solution Approach 2:
The patent extracts the reference light receiver from the conventional front-side illumination arrangement and positions it on the back side of the substrate, illuminated through the substrate from the circuit board side. This extraction allows the reference channel to be optically isolated from the measurement channel without requiring additional barrier structures, enabling small component size while maintaining manufacturability
2Reliability
If traditional packages with separate chambers are used for measurement and reference channels, then optical separation is achieved, but device complexity and construction space increase
Solution Approach 1:
The patent merges the measurement channel and reference channel into a single integrated semiconductor component structure, with both receivers arranged on the same substrate. The optical separation is achieved through selective illumination paths rather than physical chamber separation, thereby reducing device complexity while maintaining reliable optical isolation between channels
Solution Approach 2:
The substrate serves multiple functions: it acts as the mounting platform for both the measurement and reference light receivers, provides the illumination path for the reference channel, and enables electrical connections through the circuit board. This multi-functionality eliminates the need for separate chambers and reduces overall device complexity while maintaining optical separation
3Device complexity
If the reference light receiver is illuminated from the front side like the measurement channel, then both receivers are in the same chamber, but interference light affects the measurement channel and short time of flight measurements are not possible
Solution Approach 1:
The patent changes the illumination dimension for the reference light receiver from front-side (same plane as measurement channel) to back-side illumination through the substrate. This dimensional change creates separate optical paths for reference and measurement channels, eliminating cross-talk and enabling accurate short time of flight measurements while maintaining a simple single-chamber structure
Solution Approach 2:
The substrate acts as an intermediary element that guides the reference light from the circuit board side to the reference light receiver. This intermediary path isolates the reference channel optically from the measurement channel, preventing interference light from affecting the measurement receiver while allowing both channels to coexist in the same physical package
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 design enhances the accuracy of distance measurements by providing an independent optical reference signal that is less affected by aging and temperature influences, enabling precise time of flight measurements and reducing construction costs by eliminating the need for additional chambers.
Implementation Method 1
the semiconductor component is light transmitting to a limited extent such that some of the transmitted light can pass through the semiconductor component and is incident on the reactive surface of the reference light receiver
Implementation Method 2
one or more optical elements conducts some of the transmitted light to a reference light receiver
Implementation Method 3
The direction of the portion of the transmitted light that is incident on the reference light receiver is directed here such that only the reference light receiver is impinged and not the measurement light receiver
Implementation Method 4
a measurement light receiver for generating a received signal from transmitted light reflected by objects in the monitored zone
Implementation Method 5
the control and evaluation unit is configured to determine an object distance from a time of flight between the transmission of the transmitted light and the reception of the reflected transmitted light
Data Source
AI summary
An optoelectronic sensor for the detection of objects in a monitored zone having a light transmitter for transmitting transmitted light, having a measurement light receiver for generating a received signal from transmitted light reflected by objects in the monitored zone, having a control and evaluation unit for determining information on objects in the monitored zone using the received signal, and having one or more optical elements that are arranged in the optical path of the transmitted light of the light transmitter such that some of the transmitted light moves into the monitored zone as detection light, wherein the optical element conducts some of the transmitted light to a reference light receiver, wherein the measurement light receiver and the reference light receiver are arranged on a semiconductor component, with the semiconductor component being arranged on a circuit board, and with the measurement light receiver only being illuminated by the portion of the transmitted light through the side of the semiconductor component facing the circuit board.