Low Coherent Light Probe for Narrow Hole Measurement
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Solution Overview
Problem
Conventional surface state meters with contacting probes face difficulties in measuring the inner surface shape of holes with narrow entries that widen further in, as small probes cannot contact the inner surface at deeper points, making accurate measurement challenging.
Innovation Solution
An inner surface measuring apparatus utilizing low coherent light, a straight rod-shaped probe, and a rotation mechanism to accurately measure the inner surface shape by interfering low coherent lights and optionally incorporating illumination and fluorescent substances for enhanced imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a small contacting probe is used to pass through the narrow entry of the hole, then the probe can enter the hole, but it cannot make contact with the inner surface at the deeper end where the hole widens
Solution Approach 1:
The patent replaces the mechanical contacting probe system with an optical measurement system. A light source emits light that passes through a narrow probe, reflects off the inner surface of the hole, and returns through the probe to a detector. This optical system eliminates the need for a long mechanical probe while enabling measurement of deep, widening holes.
Solution Approach 2:
The patent introduces light as an intermediary medium to transfer measurement information. Instead of directly contacting the inner surface with a probe, light serves as the mediator that carries information about the inner surface shape from the measurement location back to the detector through the probe.
2Device complexity
If a contacting probe is used to measure surface shape, then the measurement method is simple, but it cannot accurately measure inner surfaces of holes with varying diameters
Solution Approach 1:
The patent replaces the simple mechanical probe system with an optical measurement system that uses light propagation through a narrow probe. This substitution maintains relative simplicity while dramatically improving adaptability to various hole geometries, including those with varying diameters and widening profiles.
Solution Approach 2:
The optical measurement system serves multiple functions: it can measure inner surfaces of holes with different geometries (narrow entries, widening profiles, constant diameters), eliminate the need for probe length calculations, and provide accurate measurements without mechanical contact. This multi-functionality resolves the contradiction between simplicity and adaptability.
3Illumination intensity
If light is used to illuminate the measurement object, then imaging is enhanced, but flare occurs in the captured images
Solution Approach 1:
The patent introduces a fluorescent substance as an intermediary between the light source and the measurement object. The fluorescent substance absorbs light at one wavelength and emits light at a different wavelength, serving as a wavelength-converting mediator that enables effective illumination while preventing flare in the captured images.
Solution Approach 2:
The patent changes the wavelength parameter of the illumination light by using a fluorescent substance that converts light from one wavelength to another. This wavelength transformation allows the use of bright illumination while avoiding the flare problem that occurs when direct light enters the detector, as the emitted fluorescent light has different optical properties.
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 highly accurate measurement of inner surface shapes, particularly in holes with narrow entries that widen, by using low coherent light interference and providing clear images, reducing flare and improving measurement precision.
Implementation Method 1
a low coherent light source that outputs low coherent light; a low coherent light dividing section that divides one portion of the low coherent light outputted from the low coherent light source in to two; a light path length adjusting section that adjusts a light path length of one of the low coherent lights divided by the low coherent light dividing section; a straight rod shaped probe that irradiates the other of the low coherent lights divided by the low coherent light dividing section from a front end section onto a measurement object arranged in a direction intersecting with the lengthwise direction of the probe
Implementation Method 2
on the front end of the probe there may be provided a fluorescent substance that generates visible light when excited by the excitation light
Data Source
AI summary
The inner surface shape of a hole, in particular, the inner surface shape of a hole the entry of which is narrow and which becomes wider further in from the entry, can be measured at a high level of accuracy. An inner surface measuring apparatus is provided which comprises: a low coherent light source that outputs low coherent light in to two; a low coherent light dividing section that divides one portion of the low coherent light; a light path length adjusting section that adjusts a light path length of one of the low coherent lights divided by the low coherent light dividing section; a straight rod shaped probe that irradiates the other of the low coherent lights divided by the low coherent light dividing section from a front end section onto a measurement object arranged in a direction intersecting with the lengthwise direction of the probe; a low coherent light multiplexing section that multiplexes a low coherent light that returns having been reflected on the measurement object with the one low coherent light whose light path length has been adjusted by the light path length adjusting section; a light detector that detects the multiplexed low coherent light; and a rotation mechanism that relatively rotates the probe and the measurement object about an axis along the lengthwise direction of the probe.