Design and Testing of a Micro-thermal Sensor Probe for Nondestructive Detection of Defects on a Flat Surface

Abstract

This paper presents a design and testing of a micro-thermal sensor probe for realizing the proposed concept of non-contact surface defect detection, in which a change in heat flow across the gap between the tip of the micro-thermal sensor probe and a target surface is utilized to recognize the existences of surface defects. In the proposed concept of surface defect detection, the probe tip, where the micro-thermal sensor is embedded, is required to be placed as close as possible to the target surface for highly sensitive surface defect detection. For the purpose, an optical tilt detection assembly based on the laser autocollimation is designed to detect relative tilt of the micro-thermal sensor with respect to a target surface. A sensor probe assembly, in which the fabricated micro-thermal sensor is embedded to the tip of a hollow-shaped piezoelectric actuator by using a homemade sensor mount, is also designed in such a way that the sensor element will face to a target surface. A prototype micro-thermal sensor probe is constructed by integrating the optical tilt detection assembly and the sensor probe assembly, and some experiments have been carried out to verify the basic performances of the prototype micro-thermal sensor probe.

State of the Art in Defect Detection Based on Machine Vision

“…In the era of Industry 4.0, in order to make the machine more intelligent, comprehensive sensing detection technology should be further studied [277]. Visual inspection can be combined with micro-thermal sensors [278], ultrasonic guided waves [279], eddy current detection [280], laser scanning thermography [281], etc., to achieve a full range of inspection and evaluation of objects.…”

Phase Compensation of the Non-Uniformity of the Liquid Crystal on Silicon Spatial Light Modulator at Pixel Level

“…The development of Micro-nano manufacturing techniques [ 1 , 2 , 3 ] brings great improvements to the spatial light modulator (SLM) and makes it possible to be employed in the advanced optical applications. The active research fields of SLM include adaptive optics [ 4 ], optical vortex [ 5 ], diffractive optical elements (DOEs) [ 6 , 7 ] and holographic displays [ 8 ].…”