Pulsed Light Detector Array Signal Synthesis for Noise Reduction

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Solution Overview

Problem

Existing devices for detecting pulsed light emitted and reflected from objects suffer from inaccuracies, particularly under sunlight conditions, due to high noise levels and reduced signal-to-noise ratios.

Innovation Solution

The use of a light-receiving element array with multiple small sub-light receiving areas synthesizes current signals to reduce random noise and enhance the signal-to-noise ratio, while a high-pass filter eliminates the DC component, allowing for accurate detection of pulsed light even in adverse weather conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single light receiving element is used to detect pulsed light, then the device structure is simple, but the detection accuracy is low due to high noise levels and reduced signal-to-noise ratio

Engineering Contradiction:
Improvedetection accuracyVSAvoiddevice structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The light receiving element is divided into multiple sub-light receiving areas (first sub-light receiving area, second sub-light receiving area, etc.). Each sub-area independently detects light signals and generates current signals. This segmentation allows the system to process multiple signals simultaneously, improving signal-to-noise ratio through signal synthesis while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If multiple sub-light receiving areas are used to synthesize current signals, then the signal-to-noise ratio is enhanced, but the device complexity increases

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoiddevice structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The current signals from multiple sub-light receiving areas are synthesized (combined) to produce an output signal. This merging process enhances the signal-to-noise ratio by accumulating useful signal components while averaging out random noise. The synthesis is achieved through electrical connection of the sub-elements, providing a straightforward implementation that balances performance improvement with structural simplicity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

A high-pass filter is introduced to extract the pulsed light signal component from the synthesized current signal by removing the DC component. This extraction process isolates the useful AC signal (pulsed light detection) from the unwanted DC offset, further improving detection accuracy without significantly increasing device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If the DC component is not removed from the detected signal, then the detection process is simpler, but the accuracy of pulsed light detection is reduced due to noise interference

Engineering Contradiction:
Improvedetection accuracyVSAvoidsignal processing
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The high-pass filter is specifically designed to extract and remove the DC component from the synthesized current signal. By taking out the unwanted DC offset, the filter preserves the AC signal components that contain the pulsed light information while eliminating a major source of noise and interference, thereby improving detection accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The high-pass filter acts as an intermediary element between the signal synthesis stage and the final detection stage. It mediates the signal by selectively passing AC components (pulsed light signals) while blocking DC components, thus preparing the signal for accurate detection without requiring complex processing in subsequent stages.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 improves the accuracy of pulsed light detection and extends the detection range, enabling reliable object recognition and distance measurement, even in environments with sunlight and adverse weather.

Implementation Method 1

a plurality of light receiving elements 1 to receive the pulsed light; current signals output from the plurality of light receiving elements 1 are synthesized

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3128346B1Pulsed light detector, object detector, sensor, movable device, and pulsed light detecting method
Publication Date: 2019.07.03 RICOH CO LTD
  • EP3128346B1 patent drawingFigure 1
  • EP3128346B1 patent drawingFigure 2A~2C
  • EP3128346B1 patent drawingFigure 3

AI summary

A pulsed light detector (150) to detect pulsed light projected onto and reflected from an object includes a light-receiving element array (10). The light-receiving element array (10) includes a plurality of light receiving elements (1) with output terminals (3) connected to each other to receive the pulsed light.