Optical Angle Detection for Reflecting Mirror Shape Measurement

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Solution Overview

Problem

Conventional non-contact optical probes face challenges in accurately measuring the rotation angle of a reflecting mirror for high-accuracy shape measurement, as rotary encoders add load and size constraints to the motor, making high-speed scanning difficult and the apparatus larger.

Innovation Solution

An illumination apparatus that divides light into two portions, where one portion is used to calculate the reflection angle of a reflecting mirror with a calculator, eliminating the need for a rotary encoder and allowing for a smaller, more accurate measurement system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a rotary encoder is attached to the motor to detect the rotation angle of the reflecting mirror, then the measurement precision is improved, but the device complexity and size increase

Engineering Contradiction:

Improverotation angle detection accuracyVSAvoidsystem structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical rotary encoder system with an optical-based angle calculation system. Instead of mechanically detecting the rotation angle through a rotary encoder, the system uses optical signals and mathematical calculations to determine the mirror's reflection angle, thereby eliminating the mechanical detection components and reducing device complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary calculation system that uses optical signals as mediators. Rather than directly measuring the rotation angle with a rotary encoder, the system uses optical paths and signal processing as intermediaries to indirectly calculate the angle, simplifying the overall system structure

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a rotary encoder is attached to the motor to detect the rotation angle, then the measurement precision is improved, but the motor size and apparatus size increase

Engineering Contradiction:

Improverotation angle detection accuracyVSAvoidmotor and apparatus size

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent eliminates the need for a rotary encoder by substituting mechanical angle detection with an optical calculation system. This removal of mechanical detection components directly reduces the motor size and overall apparatus volume while maintaining measurement precision through mathematical angle calculation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If a rotary encoder is attached to the motor to detect the rotation angle, then the measurement precision is improved, but the motor load increases making high-speed scanning difficult

Engineering Contradiction:

Improverotation angle detection accuracyVSAvoidmotor load

Core Design Contradiction:

Measurement precisionVSForce

Solution Approach 1:

The patent replaces the mechanical coupling between the motor and angle detection system with an optical signal-based system. By eliminating the rotary encoder's mechanical connection to the motor, the motor no longer bears the additional load of driving the encoder, enabling high-speed scanning operations

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

Enables high-accuracy calculation of the reflection angle of the mirror, facilitating precise shape measurement without the need for a rotary encoder, resulting in a smaller and more efficient measurement apparatus.

Implementation Method 1

The optical system divides the light from the light source into the first divided light and a second divided light

Methodology Applied

Scientific EffectLight division:

Implementation Method 2

the reflecting mirror includes a first reflecting portion and a second reflecting portion, and is capable, while changing a reflection angle, of reflecting and directing at an object a first divided light

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 3

The calculator is capable of calculating the reflection angle of the reflecting mirror by receiving the second divided light reflected by the second reflecting portion

Methodology Applied

Scientific EffectOptical angle measurement:

Data Source

PatentUS9500474B2Illumination apparatus, illumination method, measuring apparatus, and measuring method

Publication Date: 2016.11.22 MITUTOYO CORP

AI summary

An illumination apparatus according to the present invention includes a light source, a reflecting mirror, an optical system, and a calculator. The reflecting mirror includes a first reflector and a second reflector, and is capable, while changing a reflection angle, of reflecting and directing at an object a first divided light, the first divided light being a portion of light from the light source emitted at the first reflector. The optical system divides the light from the light source into the first divided light and a second divided light, and guides the second divided light to the second reflector. The calculator is capable of calculating the reflection angle of the reflecting mirror by receiving the second divided light reflected by the second reflector.