Probe Tip Optical Path Switching to Suppress Stray Light

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Solution Overview

Problem

Existing distance measuring devices suffer from stray light in the probe tip end section, leading to erroneous measurements and reduced accuracy due to reflections inside the probe tip end.

Innovation Solution

The device incorporates a probe tip end section with an optical path switching element that switches the measurement light's direction based on polarization, and an absorbing wall opposite to the optical path switching element to reduce stray light, using materials like neutral density filters or coatings to absorb light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the optical path switching element is used to switch the irradiation direction of measurement light, then measurement in lateral direction and depth direction can be performed, but stray light is generated by reflecting inside the tip end of the probe causing erroneous measurement

Engineering Contradiction:

Improvemeasurement capability in lateral and depth directionsVSAvoiddistance measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent extracts and removes the harmful stray light reflections from the measurement path by introducing an absorbing wall that selectively absorbs reflected light at specific locations within the probe tip end section, thereby eliminating the harmful factor while preserving the useful measurement function

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The absorbing wall acts as an intermediary element between the optical path switching element and the target object, intercepting and absorbing stray light reflections before they can interfere with the measurement, thus mediating between the conflicting requirements of optical path switching and measurement precision

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 configuration enhances measurement accuracy by minimizing stray light, preventing erroneous detections and improving the precision of distance measurements.

Implementation Method 1

a rotation mechanism that rotates the probe tip end section, the probe tip end section including an optical path switching element, the optical path switching element switching a direction of emitting the measurement light to the outside of the probe tip end section on the basis of the polarization of the measurement light

Methodology Applied

Scientific EffectPolarization: Polarisation

Implementation Method 2

a material of at least a part of the probe tip end section provided at a position opposite to the fifth surface absorbs the measurement light

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS20260036416A1Distance Measuring Device and Distance Measuring Method

Publication Date: 2026.02.05 HITACHI HIGH TECH CORP

AI summary

A distance measuring device measures a distance to a target object with high accuracy by reducing stray light in a probe tip end section.In the distance measuring device, the probe tip end section has an optical path switching element that switches an optical path of measurement light incident from the optical element, at a tip end of the probe tip end section. A material of at least a part of the probe tip end section provided at a position opposite to a fifth surface absorbs the measurement light.