JPS5917364B2 - Optical roughness measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical method for measuring the roughness of a surface using an optical fiber, and more particularly to an optical method for measuring the roughness in which the influence of the reflectance of the surface is removed. It is.

When light is shined onto the surface to be measured through an optical fiber, the amount of reflected light changes depending on the roughness of the surface to be measured, so the roughness of the surface can be determined by measuring the amount of light. Since the reflectance differs depending on the material used, the influence of this reflectance must be removed. The present invention aims to provide a method for measuring surface roughness by correcting the influence of reflectance using simple means.・The reflected light of the light projected onto the surface to be measured through the input fiber group, with the end face of the fiber facing the surface to be measured, and when this optical fiber is placed perpendicularly to the surface to be measured and when placed at an angle. is received by a photoelectric element through a group of light-receiving fibers,
This method is characterized in that the roughness is determined by removing the influence of the reflectance of the material forming the surface to be measured based on the difference in the characteristics of the photoelectric output in each case.

The method of the present invention will be described in detail with reference to the drawings.
As shown in the figure, first, an optical fiber 2 formed by bundling an incident fiber group 2a and a light receiving fiber group 2b is arranged perpendicularly (θ=0) to the surface to be measured 1, and its end surface is The light from the light source 3 facing the other end of the input fiber group 2a is projected onto the surface to be measured 1 through the input fiber group 2a, and the reflected light from the surface to be measured is transmitted through the light receiving fiber group 2b. When light is received by the photoelectric element 4,
As shown in the experimental example of FIG. 2a, it is possible to obtain a photoelectric output that changes depending on the roughness of the surface to be measured. Furthermore, as shown by the chain line in FIG. 1, when the optical fiber 2 is tilted at an appropriate angle θ with respect to the surface to be measured 1 and the reflected light from the surface to be measured is similarly received by the photoelectric element 4, As shown in FIG. 2, it is possible to obtain a photoelectric output that changes depending on the roughness of the surface to be measured.

Note that the horizontal axis in FIGS. 2a and 2b indicates the clearance between the end face of the optical fiber and the surface to be measured. As can be seen from these measurement results, optical
The photoelectric output when the optical fiber 2 is placed perpendicular to the surface to be measured 1 increases as the roughness of the surface to be measured increases, and when the optical fiber 2 is placed at an angle to the surface to be measured 1. On the other hand, the rougher the surface to be measured, the smaller the output, and both photoelectric outputs can be used to indicate the roughness of the surface to be measured. The roughness of the surface to be measured can be determined by taking the ratio of the two photoelectric outputs, which eliminates the influence of the reflectance of the material.

In other words, in Figure 3, the roughness is taken as the horizontal axis and the ratio of the two photoelectric outputs is calculated, and the ratio (Vθ=07Vθ=
Even for materials with different reflectances (SUS and S55C), the values of 15) are located on the same straight line, with the influence of reflectance eliminated. Therefore, by checking the characteristics of the measurement system in advance, it is possible to directly measure the reflectance-corrected roughness only from the surface to be measured. in this way,
According to the method of the present invention, in an optical roughness measurement method that does not contact the surface to be measured, the amount of incident reflected light can be calculated when the optical fiber is placed perpendicularly to the surface to be measured and when it is placed at an angle. By extremely simple measurement, the roughness of the surface to be measured can be determined by correcting the influence of the reflectance of the material.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the present invention, and FIGS. 2A, b, and 3 are diagrams showing experimental results. 1... Surface to be measured, 2... Optical.
Fiber, 2a... Input fiber group, 2b.
...Fiber group for light reception, 3...Light source, 4
・・・・・・Photoelectric element.

Claims (1)

[Claims] 1. When the end face of an optical fiber made by bundling a group of input fibers and a group of receiving fibers faces the surface to be measured, and when this optical fiber is arranged perpendicularly to the surface to be measured and when it is arranged at an angle. , the reflected light of the light projected onto the surface to be measured through the input fiber group to the projection side is received by the photoelectric element through the light receiving fiber group,
An optical roughness measuring method characterized in that the roughness is determined by removing the influence of the reflectance of the material forming the surface to be measured by taking the ratio of the photoelectric outputs in each case.