JPH0280905A - Height measuring method - Google Patents

Abstract

PURPOSE:To rapidly measure a height with high accuracy by performing the scanning of laser beam in an X-axis direction and calculating the position of an inflection point on a scanning line from the quantity of reflected beam and subsequently performing the scanning in a Y-axis direction to calculate the position of an apex to measure a height. CONSTITUTION:The quantity of reflected beam and a height signal are detected while a Y-stage 5 is moved around the apex of an object 3 to be measured at a constant speed by a control means 9. The center position 17 between a position 15 where the quantity 10 of reflected beam exceeds a judge level TH and a position 16 where said quantity 10 is short of said level TH is judged at an inflection point by a judge means 12 and set to the Y-coordinates of an apex position 2. Next, the stage 5 is moved so that an initial position comes to the Y-coordinates of the position 2 by the means 9, and the quantity of reflected beam and the height signal are detected while an X-stage 6 is moved. The center position 19 is judged from the quantity 10 of reflected beam in the same way. Since this position 19 is the apex position of the object 3, the height signal of this position becomes that of the apex position. Therefore, scanning is respectively once performed in the X- and Y-axis directions to make it possible to rapidly measure a height with high accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of measuring the height of an object to be measured using a light beam, particularly when the object to be measured is not precisely positioned. The present invention relates to a method for measuring the height of the apex position.

[Conventional technology]

Conventionally, various methods are known for measuring the height of an object in a non-contact manner using a light beam. Among them, when the precise positioning of the object to be measured is not performed, that is, when the apex of the object to be measured is not at a predetermined position, the method described in Japanese Patent Application Laid-open No. 196608-1983 is known as a method for determining the height of the object. It is being This method uses x, y, and z as three-dimensional orthogonal coordinates, scans the Y coordinate with a light beam in coarse steps, detects the vicinity of the inflection point using a predetermined inspection method, and then scans the vicinity of the inflection point with Y/ ! The IHI is scanned in finer steps, then the X coordinate is scanned in one step, and these steps are repeated.

[Problem to be solved by the invention]

The above conventional technology does not take measurement time into consideration, and when the apex of the object to be measured is not at a predetermined position, it is necessary to scan the entire area around the apex of the object to find the apex position, resulting in high accuracy. However, there was a problem that it was not suitable for high-speed measurement.

An object of the present invention is to provide a method for quickly and accurately measuring the height of an object to be measured even when the apex of the object is not at a predetermined position.

[Means to solve the problem]

The above purpose is to irradiate a spherical object to be measured with a light beam from diagonally above, scan the light beam relative to the object to be measured, and detect the reflected light with a position detection element. In a method of measuring the height of a light beam irradiation position of an object and measuring the height of the vertex of the object to be measured, relative scanning of the light beam is performed in the X-axis direction of the coordinate axes of the object to be measured.

The position of the inflection point on the scanning line is determined from the amount of reflected light of the light beam, and then relative scanning of the light beam is performed in the Y-axis direction including the inflection point, and the position of the apex is determined from the amount of reflected light of the light beam. This is achieved by a height measuring method characterized in that the height of the object to be measured at the position of the vertex is determined from the reflected light.

[Effect]

In the present invention, the relative scanning of the light beam only needs to be done once in each of the X-axis direction and the Y-axis direction.

The apex position and height of a spherical object to be measured whose position has not been precisely determined can be quickly and accurately determined.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

FIG. 2 is a configuration diagram showing the configuration of a height measuring device for carrying out the present invention. A plurality of hemispherical objects 3 to be measured are mounted close to each other on a base 4.

The detector 7 is a detection head portion of a conventional height measuring instrument, and has a light source that emits a light beam in an oblique direction and a position detection element for reflected light. The distance between the object to be measured and the detector is measured using the principle of trigonometry. A reflected light amount 10 and a height signal 11 are sent from the measuring device main body 8 to a control means 9 having a memory 13 and a determining means 12. The base 4 is movable in the X direction and the Y direction by an X stage 6 and a Y stage 5.

FIG. 1 is an explanatory diagram illustrating the principle of the measuring method of the present invention. Further, FIGS. 3 and 4 are diagrams showing the relationship between the light beam scanning position in the Y direction and the X direction, the amount of reflected light, and the height of the object at the light beam irradiation position, respectively, due to stage movement.

Hereinafter, a case will be described in which the heights of the vertices of - number of objects to be measured 3 are measured. As shown in Fig. 1, the object to be measured 3
Detecting the amount of reflected light and the height signal while moving the Y stage 5 at a constant speed by the control means 9 so that the light beam scans around the apex position 2 according to the Y direction scanning position 1a,
The amount of reflected light lO and the height signal 11 shown in FIG. 3 are detected. The determination means 12 determines the determination level 1 with the amount of reflected light 10.
Center position 17 between position 15 beyond 4 and position 16 cut
is determined to be an inflection point. This position becomes the Y coordinate of vertex position 2.

Next, the control means 9 moves the Y stage 5 so that the initial position is on the Y coordinate, and moves the X stage 6 at a constant speed so that the light beam scans according to the X direction scanning position 1b, and the amount of reflected light is and height signals are detected, and the results shown in FIG. 4 are obtained.

For the amount of reflected light 10, the center position 19 is determined in the same manner as described above. Since this center position 19 is the apex position 2 of the object to be measured 3, the height signal at this position becomes the height of the desired apex position.

The stage scanning speed in the X direction and Y direction is determined in relation to the sampling pitch. Furthermore, even if the object to be measured 3 is different and its surface has a different reflectance, this can be handled by changing the determination level 14.

FIG. 5 is a diagram showing the scanning order of the X stage 6 and the Y stage 5 when measuring the height of each vertex of a plurality of spherical objects to be measured 3 arranged in three columns and three rows.

The procedure is to scan the Y stage 5 once for each column to obtain the coordinates of the apex in the Y direction of each spherical object 3 using the method described above, and to store these coordinates in the memory 13 in the control means 9. The X stage 6 is continuously scanned row by row, and the amount of reflected light 10 and the height signal 11 are sampled. On this occasion,
In front of each spherical object to be measured 3, the Y stage 5 is corrected and moved to the respective Y-direction apex coordinate positions previously stored in the memory 13.

Since this correction movement does not involve sampling of the amount of reflected light and the height signal, it is not necessary to move at a constant speed, and it can be easily realized. Using the method described above, the height of each vertex is determined from the amount of reflected light and the height signal of each sampled object to be measured. This arithmetic processing can also be performed in real time every time the scanning of each object to be measured is completed.

In the above-described embodiment, the Y-direction scan was performed first and the X-direction scan was performed next, but this is due to the measurement accuracy described below. That is, the spot diameter of the light beam emitted by the detector 7 has a finite size of 1, for example, several tens of digits, and the height of the light receiving element for the 5 light beams is determined based on the position of the center of gravity of the beam.

Therefore, the height can be stably detected before and after the apex position 2 of the spherical object 3 by scanning in the Y direction perpendicular to the plane including the incident and reflected directions of the light beam, as shown in Fig. 3. Compared to
As shown in the figure, a height signal offset before and after the vertex position is output.

In other words, the final apex position measurement accuracy will be improved if the X stage scanning is performed later in order to make it less susceptible to the influence of the resolution of correction movement and positioning accuracy.

According to the embodiment described above, two sampling scans are required to measure the apex positions and heights of - number of objects to be measured, and the apex positions and heights of a plurality of spherical objects to be measured are measured. In this case, since continuous sampling scanning can be performed in units of rows or columns, the acceleration/deceleration time of the stage can be omitted, and the apex position and height can be quickly measured. As the number of objects to be measured increases, the efficiency will further improve.

〔Effect of the invention〕

According to the present invention, the relative scanning of the light beam is performed twice in total, once in the X-axis direction and once in the Y-axis direction.

Since the apex position of the object to be measured, which has not been precisely positioned, can be determined, the height can be quickly measured.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram illustrating the principle of the measurement method of the present invention,
Fig. 2 is a block diagram showing the structure of an embodiment of a height measuring device for carrying out the present invention, and Figs. 3 and 4 show the light beam scanning position in the Y direction and the X direction by stage movement, respectively. FIG. 5 is a diagram showing the relationship between the amount of reflected light and the height of the object at the light beam irradiation position, and is an explanatory diagram of stage scanning. 1a...Y direction scanning position 1b...X direction scanning position 2...Vertex position 3...Object to be measured 4.
...Base 5...Y Stage 6...X
Stage 7...Detector 8...Measuring instrument body
9...Control means 10...Reflected light amount
11... Height signal 12... Judgment means 13
...Memory 14...Judgment level 15.16
...Position 17.19...Central position attorney Junnosuke Nakamura Figure 5

Claims (1)

[Claims] 1. A light beam is irradiated onto a spherical object to be measured from diagonally above, the light beam is scanned relative to the object to be measured, and the reflected light is detected by a position detection element to detect the object to be measured. In a method of measuring the height of a light beam irradiation position and measuring the height of a vertex of an object to be measured, the relative scanning of the light beam is performed in the X-axis direction of the coordinate axis of the object to be measured,
The position of the inflection point on the scanning line is determined from the amount of reflected light of the light beam, and then relative scanning of the light beam is performed in the Y-axis direction including the inflection point, and the position of the apex is determined from the amount of reflected light of the light beam. , and the height of the object to be measured at the position of the vertex is determined from the reflected light.