Light-Receiving Section Voltage Control for Stray Light Interference

Solution Overview

Problem

Current distance measurement devices face challenges in achieving accurate distance measurement, particularly due to issues like scattered stray light from soiled optical windows, which can lead to detection errors, especially when measuring targets at short distances.

Innovation Solution

The implementation of a distance measurement device that applies a standby voltage to the light-receiving section during a predetermined non-operating period after the light-emitting section operates, preventing avalanche phenomena caused by scattered stray light and ensuring accurate distance calculation by switching to an operating voltage only when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the light-receiving section operates continuously to detect reflected light, then detection capability is maintained, but false detection occurs due to scattered stray light from soiled optical windows

Engineering Contradiction:

Improvedetection accuracyVSAvoidscattered stray light interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The control section applies a standby voltage to the light-receiving section before the light-emitting section operates, preparing it in advance. This preliminary action ensures that when the light pulse is emitted, the light-receiving section is already in a state ready to detect reflected light accurately, while maintaining low sensitivity during the emission phase to avoid detecting scattered stray light from soiled optical windows.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The light-receiving section operates in periodic cycles: applying standby voltage before light emission, switching to operating voltage after light emission, and returning to standby voltage before the next emission. This periodic switching between voltage states allows the system to maintain detection capability while periodically avoiding interference from scattered stray light during each light emission cycle.

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If the operating voltage is applied continuously to the light-receiving section, then detection sensitivity is maximized, but measurement accuracy deteriorates due to avalanche phenomena from scattered light

Engineering Contradiction:

Improvedistance measurement accuracyVSAvoidavalanche phenomena from scattered light

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The control section applies a standby voltage to the light-receiving section before the light-emitting section operates, preparing it in advance. This preliminary action ensures that when the light pulse is emitted, the light-receiving section is already in a state ready to detect reflected light accurately, while maintaining low sensitivity during the emission phase to avoid detecting scattered stray light from soiled optical windows.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The light-receiving section operates in periodic cycles: applying standby voltage before light emission, switching to operating voltage after light emission, and returning to standby voltage before the next emission. This periodic switching between voltage states allows the system to maintain detection capability while periodically avoiding interference from scattered stray light during each light emission cycle.

Inventive Principle:

Principle #19Periodic action

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 enhances the accuracy of distance measurement by preventing false signals from scattered stray light and ensuring proper detection of reflected pulsed light, even at short distances, thereby reducing measurement errors.

Implementation Method 1

a light-emitting section that emits pulsed light toward a measurement target and a light-receiving section that receives reflected pulsed light from the measurement target

Methodology Applied

Scientific EffectLight emission and detection: Light

Implementation Method 2

scattered stray light from soiled optical windows, which can lead to detection errors

Methodology Applied

Scientific EffectAvalanche photodetection: Avalanche Breakdown

Data Source

PatentUS11397250B2Distance measurement device and distance measurement method

Publication Date: 2022.07.26 SONY GROUP CORP

AI summary

Disclosed is a distance measurement device including a control section. The control section executes control so that an operating voltage for operating a light-receiving section is applied to the light-receiving section at a second time point. The second time point is later than a first time point by a predetermined time. The first time point is a time point at which a light-emitting section operates.