Optical Probe Using Digital Mirror Device for Shape Measurement
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Solution Overview
Problem
Conventional non-contact optical probes face challenges in accurately measuring objects with mirror planes or corners due to multiple reflections, which can result in false shape measurements, and require complex moving mechanisms that are difficult to maintain.
Innovation Solution
A non-contact optical probe that uses a laser light source, collimator lens, and a light shape changing section to convert laser light into linear light, which is then controlled by a controller to irradiate an object sequentially from one end to the other, using a Digital Mirror Device (DMD) or liquid crystal shutter array to reflect selected parts of the linear light, eliminating the need for moving mechanisms and allowing easy recognition of virtual images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a moving mechanism (galvanometer mirror or polygon mirror) is used to scan laser light across the work surface, then the measurement can be performed in sequence, but the device complexity increases and maintenance becomes difficult
Solution Approach 1:
The patent replaces the mechanical scanning system (galvanometer mirror or polygon mirror) with a stationary optical system. The beam expander is fixed without any moving parts, and the linear laser light is generated optically rather than through mechanical scanning. This substitution eliminates the need for complex moving mechanisms while maintaining the ability to measure the work surface, thereby resolving the contradiction between measurement capability and device complexity.
2Productivity
If linear laser light is constantly thrown at the work surface, then the form can be obtained at one time, but real and virtual images cannot be distinguished due to multiple reflections
Solution Approach 1:
The patent employs periodic action by sequentially turning on and off specific micromirrors in the DMD device. Instead of constantly illuminating the entire work surface, the system activates individual micromirrors in sequence to scan the linear laser light across the work surface. This periodic activation allows the system to maintain high measurement efficiency while enabling distinction between real and virtual images through sequential detection, thereby resolving the contradiction between productivity and measurement precision.
3Measurement precision
If a beam expander with moving parts is used to generate linear laser light, then the measurement can be performed, but the maintenance becomes troublesome compared to a stationary system
Solution Approach 1:
The patent replaces the mechanical beam expander system with a stationary optical system incorporating a DMD device. The beam expander is configured without moving parts, and the linear laser light generation is achieved through fixed optical components combined with electronic control of the DMD micromirrors. This replacement eliminates mechanical wear and maintenance requirements while preserving the measurement capability, thereby resolving the contradiction between measurement precision and ease of repair.
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 accurate measurement of object shapes without moving mechanisms, simplifies maintenance, and effectively distinguishes between real and virtual images formed by multiple reflections.
Implementation Method 1
a collimator lens 102 that converts laser light emitted from a laser light source 101 into parallel light
Implementation Method 2
a beam expander 103 that allows laser light to change shape into light L1 that is linear in shape
Implementation Method 3
using a Digital Mirror Device (DMD) or liquid crystal shutter array to reflect selected parts of the linear light
Implementation Method 4
detect light reflected from the surface of the work, and obtain position coordinates of the respective spots of the work
Data Source
AI summary
An optical probe includes a laser light source that emits laser light, a collimator lens that converts the laser light into parallel light, a light shape changing section that converts the parallel light into linear laser light, an irradiating section to irradiate an object with a selected part of the linear laser light, an image pickup section that picks up an image of the object based on the laser light reflected from the object, and a controller that controls irradiation of the linear laser light. The linear laser light is composed of a plurality of parts including one end part and the other end part; and the irradiating section irradiates the object with the parts of the linear laser light sequentially from the one end part to the other end part.