Optical Ranging Sensor Attenuation Wall for Noise Reduction
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Solution Overview
Problem
Optical noise from ambient light sources affects the accuracy and consistency of optical ranging sensors, leading to reduced signal-to-noise ratio and increased manufacturing complexity and cost.
Innovation Solution
A housing cap with an attenuation wall is introduced between the optical radiation source and the reference sensor, creating an attenuation gap to block ambient light while allowing optical radiation to pass, eliminating the need for additional filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ambient light is allowed to enter the optical sensor through the transmission opening, then the sensor can operate in various lighting conditions, but optical noise increases leading to inaccurate readings
Solution Approach 1:
The housing cap is segmented into multiple functional regions: a transmission opening for ambient light, a receiver opening for reflected light, and an attenuation wall with attenuation gap to block stray light. This segmentation allows different optical paths to be controlled independently, enabling the sensor to operate in various lighting conditions while maintaining reading accuracy by preventing optical noise from entering the reference sensor.
2Measurement precision
If optical filters are added to block ambient light from the reference sensor, then optical noise is reduced, but device complexity and manufacturing cost increase
Solution Approach 1:
An attenuation wall is introduced as an intermediary structure between the transmission opening and the reference sensor. This wall includes an attenuation gap that selectively blocks ambient light from reaching the reference sensor while allowing the optical radiation from the source to pass through. This geometric solution replaces complex optical filters, reducing device complexity and manufacturing cost while maintaining improved signal-to-noise ratio.
3Object-affected harmful factors
If the attenuation wall is positioned closer to the optical radiation source, then more ambient light is blocked, but the attenuation gap must be larger allowing more optical radiation loss
Solution Approach 1:
The attenuation wall parameters (position, height, and attenuation gap size) are optimized to achieve the desired balance. By adjusting these geometric parameters, the design blocks sufficient ambient light from reaching the reference sensor while maintaining adequate transmission of optical radiation through the attenuation gap, minimizing energy loss.
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
Improves accuracy and reliability of optical ranging sensors by reducing optical noise, simplifying manufacturing, and lowering costs by eliminating the need for optical filters.
Implementation Method 1
an attenuation wall positioned between the optical radiation source and the reference sensor, defining an attenuation gap through which the portion of the ranging optical radiation passes
Data Source
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AI summary
A housing cap for an optical ranging sensor and an electronic system for transmitting and receiving optical radiation while minimizing optical noise, such as ambient light, received at the reference sensor of the optical ranging sensor are provided. An example housing cap for an optical ranging sensor may include a barrier wall defining a transmission cavity and a receiving cavity. The transmission cavity including an optical radiation source positioned to direct ranging optical radiation through a transmission opening toward a target object, a reference sensor positioned to receive a portion of the ranging optical radiation, and an attenuation wall positioned between the optical radiation source and the reference sensor, defining an attenuation gap through which the portion of the ranging optical radiation passes. The receiving cavity including an optical radiation receiver positioned to receive ranging optical radiation reflected off the target object through a receiver opening.