JPS6017043B2 - How to measure the distance between two parallel planes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an article having two spaced parallel planes facing each other. The present invention relates to a method for measuring the distance between two parallel planes suitable for measuring and inspecting.

2. Description of the Related Art Conventionally, the method shown in FIGS. 1 and 2 is known as a method for optically measuring the distance between two articles.

In the method shown in FIG. 1, parallel laser light is projected as measurement light 3 between articles 1 and 2, and the amount of light 4 passing therethrough is detected by a sensor made of a photoelectric converter or the like. This is a method of knowing the interval W by utilizing the fact that the light output converted into the electric signal corresponds to the interval W. Further, in the method shown in FIG. 2, the measurement light 3 is scanned light consisting of narrow parallel laser light, and is moved in parallel in the direction of the arrow 5 to scan between the articles 1 and 2. In this method, the interval W is determined by receiving the passing light 4 that has passed between the 2 and 2 with a sensor provided at the rear, and the time of receiving the light for each scan is proportional to the interval W. The above-mentioned method allows particularly highly accurate measurement when a laser beam is used as the measurement light 3. However, when these methods are used to measure the distance between two parallel planes, various problems arise.

This will be explained using an example of the manufacturing process of an electron gun for a cathode ray tube. FIG. 3 shows the main parts of the electron gun 11.
A plurality of plate-shaped grids 12, . . . are provided in parallel and spaced apart from each other, and it is strictly measured whether the interval W is maintained at a predetermined value. If the optical method described above is applied to this measurement, the grids 12, 12 must be placed exactly parallel to the measurement light 3. That is, in FIG. 4, when measuring the distance W between two opposing parallel surfaces 13 and 14 of a pair of parallel grids 12 and 12 by the method shown in FIG. If the measurement is made in a tilted state, then W', which is smaller than W, will be obtained instead of W. Therefore, in the case of an electron gun that does not have a flat reference surface, it is fixed at a predetermined position during measurement, which reduces work efficiency.
Moreover, because it is difficult to ensure accuracy, the current situation is that we generally rely on thickness gauges, which have poor accuracy and efficiency.
Moreover, there were other inconveniences such as accidents that caused damage to the grid. The present invention has been made in view of the above-mentioned circumstances, and the object to be measured is rotated so that the two parallel surfaces of the object pass through a predetermined position parallel to the measurement light, and the passing light is received by a photoelectric converter. This is a method for measuring the distance between two parallel planes in which the maximum value on that side is detected and the distance is determined, and the accuracy is high even if the two parallel planes to be measured are installed obliquely to the measurement light. This allows measurements to be taken without compromising performance, significantly improving work efficiency.

The details of the present invention will be explained below with reference to Examples.

The apparatus shown in FIG. 5 was used in the first embodiment, and is an improved version of the measuring method shown in FIG. 1, in which the electron gun 11 of a cathode ray tube is measured. The laser beam as the measurement light 3 sent out from the laser oscillation device 21 is
The diameter is enlarged by the collimator lens body 22, and the beam is projected between the two planes 13 and 14 with the diameter being slightly larger than the distance W between the two planes 13 and 14 measured by the electron gun 11. The electron gun 11 is detachably fixed to a measuring body 23, and this measuring body 23 is rotatably supported by a pin 24. The outer end surface 25 having an arc concentric with the pin 24 is in contact with the hard moat roller 27 of the motor 26, and the measurement object 23 is moved left and right at an angle of 8 through the foundation lacquer roller 27 by the forward and reverse rotation of the motor 26. Rotate for a while. In the middle of this rotation, at a certain moment the two parallel surfaces 13 and 14
becomes parallel to and passes through a predetermined position. These two parallel planes 13
, 14, the amount of light of the laser beam 3 passing therebetween becomes maximum at a position where the two planes 13 and 14 are parallel to the laser beam 3, that is, at a predetermined position, and becomes smaller both before and after that. A sensor 30 as a photoelectric converter is provided behind the measuring body 23, and all of the passing light 4 of the laser beam 3 is incident on the sensor 3. The sensor 3 outputs an output that changes according to the amount of incident light, which is input to the sensor 3 and the sensor 3, which converts the electric signal into an interval W and displays it.

Next, a second embodiment will be described with reference to FIG.

This example is an improvement on the measuring method shown in FIG. The laser beam as the measuring beam 3 sent out from the laser oscillation device 21 enters the focusing lens 35, is reflected by the vibrating mirror 37 whose rotation center 36 is placed at the focal position, and is reflected at the rotation center 36. It enters a focused scanning lens 38. This laser beam 3 is turned into a thin laser beam parallel to the optical axis of the scanning lens 38 by the scanning lens 38.
Due to the rotation of 37, the laser beam 3 changes to the laser beam 3 shown by the solid line.
While reciprocating in the direction of the arrow 5 between the position 3a of the laser beam 3 and the position 3b of the laser beam 3 shown by the broken line, the laser beam 3 enters the electron gun 11 to be measured placed at the rear. Note that the scanner 40 is composed of the Chikuto lens 35, the vibrating mirror 37, and the scanning lens 38. The electron gun 11 is detachably fixed to the measuring body 23 as in the first embodiment. Note that the measurement object 23
Since the configuration is similar to that of the first embodiment, detailed explanation will be omitted. FIG. 6 shows the moment when the two planes 13 and 14 are at a position parallel to the optical axis of the scanning lens 38, that is, at a predetermined position. The laser beam 3 scans between the two planes 13 and 14 by the rotation of the vibrating mirror 37.
The passing light 4 that has passed between the planes 13 and 14 enters a sensor 40' which is a photoelectric converter placed at the rear, and outputs an electrical signal only while the passing light 4 is incident on the sensor 40'.
While the vibrating mirror 37 is vibrating, that is, while the laser beam 3 is scanning, the measurement object 23 is rotated within an angle range of 8 by the pulse motor 26, so that the two planes 13 and 14 are With respect to the direction, the position is either an oblique position as shown in FIG. 4, or a predetermined position completely parallel to the direction shown in FIG. During this period, scanning is performed at high speed, so if the two planes 1, 3, and 14 are aligned as shown in FIG. 401 is sent to the connected signal processing device 41, and when the two planes 13 and 14 are exactly parallel to the direction of the scanning laser beam 3, it scans the interval W, and the signal is sent from the sensor 40 to the signal processing device for a corresponding period of time. The output is sent to 41. In this way, the length of the signal sending time for each forward or backward movement is determined by the scanning laser beam 3.
It is maximum when the direction of and the two planes are parallel. The signal processing bag counterfeit 41 detects the maximum light reception time value from among the plurality of signals sent within a certain period of time, and sends this to the display device 42.
Here, this value is converted into an interval W and displayed. As described in detail above, the method for measuring the distance between two parallel planes of the present invention involves projecting measurement light parallel to these planes between two parallel planes that are spaced apart from each other, and photoelectrically converting the passing light that has passed between the two planes. When measuring the distance between two planes by detecting with a converter, the two parallel planes are configured to rotate while passing through a predetermined position where they become parallel to the measurement light. The measured values obtained during the measurement always include the measured value at a predetermined position, so it is only necessary to detect this, so the two planes can be fixed near the predetermined position during measurement, and the fixing is easy. Furthermore, in combination with processing the distance using an electrical signal using a photoelectric converter, it is possible to measure with high efficiency while maintaining accuracy.

In the embodiment, a laser beam was used as the measurement light, but the measurement light is not limited to this, and any parallel light may be used.

Also, the items to be measured are not limited to electron guns.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams of subordinate examples, FIG. 3 is an explanatory perspective view showing the main parts of the article measured in each embodiment of the present invention, and FIG. 4 is an explanatory diagram of measurement error in the conventional example. , FIG. 5 is an explanatory diagram of the configuration of an apparatus for carrying out the first embodiment of the present invention,
FIG. 6 is an explanatory diagram of the configuration of an apparatus for carrying out the second embodiment of the present invention. 3, 3'... Measuring light, laser light, 13, 14...
...2 planes, 30, 40...photoelectric conversion body. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. Measurement light parallel to the two planes is projected between two parallel planes that are spaced apart from each other, and the measurement light that has passed between the two planes is detected by a photoelectric converter to measure the distance between the two planes. A method for measuring a distance between two parallel planes, characterized in that measurement is carried out while subjecting the two planes to rotation passing through a predetermined position where the two planes are parallel to the measurement light.