Polarization-Based Optical Path Switching for Miniaturized Distance Measurement

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Solution Overview

Problem

Existing distance measuring devices face limitations in miniaturization, particularly when measuring narrow portions, due to the need to move mirrors within a housing, which restricts their ability to accurately measure shapes in confined spaces.

Innovation Solution

A distance measuring device incorporating a light emitting unit, a polarization state control unit, and an optical path switching element that selectively emits measurement light in multiple directions, allowing for precise distance measurement and shape analysis without the need for mirror movement, thereby enabling miniaturization of the measuring unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a mirror is moved within a housing portion to change the direction of irradiation, then the traveling direction of measurement light can be changed to a predetermined direction, but the housing portion cannot be miniaturized

Engineering Contradiction:

Improvetraveling direction controlVSAvoidhousing portion size

Core Design Contradiction:

Length of moving objectVSVolume of moving object

Solution Approach 1:

The patent replaces the mechanical mirror movement system with a polarization-based optical path switching system. The polarization state control unit modifies the polarization of measurement light, and the optical path switching element directs the light in different directions based on polarization state, eliminating the need for mechanical mirror movement and enabling miniaturization of the housing portion.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the parameter of light polarization to control the traveling direction. By adjusting the polarization state of measurement light through the polarization state control unit, the system achieves direction control without mechanical movement. This parameter-based control allows for a compact housing portion while maintaining the ability to change irradiation directions.

Inventive Principle:

Principle #35Parameter changes

2Volume of moving object

If the housing portion is miniaturized to enable measurement of narrow portions, then the measuring device can access confined spaces, but the ability to change irradiation direction is limited

Engineering Contradiction:

Improvehousing portion sizeVSAvoidirradiation direction control

Core Design Contradiction:

Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent replaces mechanical mirror rotation with polarization-based optical path switching. The optical path switching element, controlled by the polarization state control unit, can direct measurement light in multiple directions (including 90 degrees and other predetermined directions) without requiring a large housing portion. This enables the miniaturized device to maintain versatile irradiation direction control for measuring narrow portions and complex shapes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If a mirror is rotated about a shaft to change light direction, then the traveling direction can be changed to 90 degrees or other predetermined directions, but the measurement unit cannot be miniaturized

Engineering Contradiction:

Improvelight direction switchingVSAvoidmeasurement unit size

Core Design Contradiction:

Ease of operationVSVolume of moving object

Solution Approach 1:

The patent eliminates the mechanical shaft and mirror rotation system by using polarization state control. The polarization state control unit adjusts the polarization of light, and the optical path switching element automatically directs the light in the desired direction based on the polarization state. This non-mechanical approach enables easy light direction switching while achieving miniaturization of the measurement unit.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 allows for efficient miniaturization of the measuring unit, enhancing its ability to measure narrow portions and complex shapes while maintaining accurate distance and shape measurement capabilities.

Implementation Method 1

a polarization state control unit that controls polarization of the measurement light output from the light emitting unit

Methodology Applied

Scientific EffectPolarization: Polarisation

Implementation Method 2

the optical path switching element receives reflected light with respect to an object of the measurement light emitted from the optical path switching element

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS10900773B2Distance measuring device and three-dimensional shape measuring apparatus

Publication Date: 2021.01.26 HITACHI LTD

AI summary

An object is to provide a technology capable of realizing miniaturizing of a measurement unit in a distance measuring device. The distance measuring device including a light emitting unit that outputs measurement light, a polarization state control unit that controls polarization of the measurement light output from the light emitting unit, and an optical path switching element that selectively emits the measurement light controlled by the polarization state control unit, in which the polarization state control unit controls the polarization so as to emit the measurement light in a plurality of directions from the optical path switching element, and the optical path switching element receives reflected light with respect to an object of the measurement light emitted from the optical path switching element, the reflected light being used to measure a distance to the object.