JPH0121884B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of an optical fiber used to measure the condition of an object surface by a light reflection method using an optical fiber.

A measurement method using a light reflection method using an optical fiber is to irradiate the surface of the object to be measured with a measuring beam through a light emitting fiber, and then transmit the reflected light of the measuring beam from the surface of the object to a receiving fiber. Therefore, light is received, and the condition of the surface of the object to be measured is detected from changes in the amount of received light.

For example, when measuring the roughness of the cut surface of a workpiece during cutting, the proportion of reflected light detected through the receiving fiber changes depending on the slope angle distribution of the cutting surface, and the surface roughness depends on the slope angle distribution. Because of the correlation, roughness can be measured by the reflected light output.

Here, the reflected light output varies depending on the reflectance of the surface of the object to be measured, and the reflectance also varies depending on the material of the object to be measured. Therefore, in order to accurately measure surface roughness, it is necessary to remove the influence of the difference in reflectance by some method.

As a method for this purpose, the ratio of the output of the reflected light received by the receiving fiber at each position is generally calculated when the optical fiber is placed perpendicular to the surface to be measured and when it is placed at an angle. There is a method that removes the influence of the reflectance of the material.

However, in this method, the transmitting fiber and the receiving fiber are perpendicular to and inclined to the measurement surface, and the two emitted lights interfere with each other, making accurate measurement difficult. There is this inconvenience.

The present invention was made in order to eliminate such inconveniences, and it is an object of the present invention to provide an optical fiber that is small in size, can be accurately measured, and is convenient to handle.

This purpose consists of a light-emitting fiber arranged perpendicular to the surface of the object to be measured, a light-receiving fiber parallel to and adjacent to the light-emitting fiber, and a second light-receiving fiber having a certain angle with the light-emitting fiber. This is achieved by integrally providing the following.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing an embodiment of the optical fiber according to the present invention.

As shown in this figure, the optical fiber 1 according to the present invention includes a light emitting fiber 3 that emits a measuring light beam perpendicularly to the surface of an object to be measured 2, and a central axis of the received light beam. is parallel to the central axis of the emitted light beam of the light emitting fiber 3 and arranged adjacent to the light receiving fiber 4, and the central axis of the emitted light beam of the light emitting fiber 3 and the central axis of the received light beam. a second light-receiving fiber that intersects at an angle θ on the surface of the object to be measured 2;
are integrally provided. Reference numeral 6 in the figure is the light source 7
Reference numeral 8 indicates a light-receiving element for receiving light from the light-receiving fiber 4, and reference numeral 9 indicates a light-receiving element for the second light-receiving fiber.

Here, the angle θ is ideally between 15 degrees and 40 degrees. As shown in Figure 2, this is a reflection of an optical fiber whose central axes are parallel to each other, with respect to the angle ψ between the central axis of the light beam and a line perpendicular to the surface of the object to be measured. This is based on the results of experimentally determining the relationship with optical output.

In other words, Figure 2 shows the angle ψ on the horizontal axis, and the vertical axis shows the specific output at each ψ when the reflected light output when ψ = 0 is 1. It shows the actual measured value of the roughness (Rz) of the material. According to this, it was found that when the absolute value of ψ was between 15 degrees and 20 degrees, the output ratio of each sample was most sensitive to changes in surface roughness. Therefore, setting θ between 15 degrees and 40 degrees will give you the highest altitude.

As described above, the present invention includes a light projecting fiber for irradiating a measurement light beam onto the surface of an object to be measured, and a light receiving fiber for receiving reflected light of the measurement beam from the surface of the object to be measured. In an optical fiber for detecting the state of the surface of an object to be measured from changes in the amount of received light, the central axis of the received light beam of the light receiving fiber is defined as the central axis of the light emitted by the light emitting fiber. A second light-receiving fiber is provided integrally with the light-emitting fiber and the light-receiving fiber, and the central axis of the light-receiving light beam forms a certain angle with the center axis of the light-emitting fiber. This configuration has excellent effects in that the surface of the object to be measured can be accurately measured without the two light beams interfering with each other, and the compactness and integration make it convenient to handle.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of the optical fiber according to the present invention, and FIG. 2 is a graph showing the relationship between the inclination angle of the optical fiber with respect to a line perpendicular to the surface to be measured and the reflected light output. 1... Optical fiber, 2... Measured object, 3...
Light emitting fiber, 4...Light receiving fiber, 5
...Second light receiving fiber.

Claims (1)

[Scope of Claims] 1. A light projecting fiber for irradiating a measuring beam onto the surface of an object to be measured, and a light receiving fiber for receiving reflected light of the measuring beam from the surface of the object to be measured. In an optical fiber for detecting the surface condition of an object to be measured from changes in the amount of light received, the central axis of the received light beam of the light receiving fiber is defined as the central axis of the light emitted by the light emitting fiber. A second light-receiving fiber is provided integrally with the light-emitting fiber and the light-receiving fiber, and the center axis of the light-receiving light beam forms a certain angle with the center axis of the light-emitting fiber. optical fiber. 2. The optical fiber according to claim 1, wherein the angle between the central axis of the second light-receiving fiber and the central axis of the light-emitting fiber is 15 degrees to 40 degrees.