JPH0299803A - Measuring apparatus for floating amount of transparent film - Google Patents

Abstract

PURPOSE:To make it possible to measure the amount of float excellently without being affected by vibration by a method wherein a laser light is made to fall obliquely on the surface of a transparent film, a light reflected on the surface of the film and a light reflected on the surface of a support are made incident simultaneously and a distance between them is detected. CONSTITUTION:When a laser light 4 is made to fall on a transparent film 2, a part of the light is reflected as a reflected light 4a on a surface 2a, while the light transmitted through the film 2 is reflected on a support surface 1a and projected as a reflected light 4b. A light-detecting means (incorporated in a TV camera) 5 detects the lights 4a and 4b separately and measures a distance l1 between them. Prior to this operation, a distance l0 between reflected lights 4a' and 4b' is measured likewise with respect to a transparent film 2' which is made of the same material and has the same thickness as the film 2 and whose amount of float is zero, and it is stored in a memory 10. An arithmetic unit 6 calculates the amount x1 of float of the film 2 from an equation x1=(l1-l0)/(2x1sin theta) (theta is an incident angle of the light 4) by using the distances l0 and l1. With the angle theta (the distance l0) set at a prescribed value, the amount x1 of float can be measured only by determining the distance l1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a transparent film disposed on an opaque support surface.
The present invention relates to a device for measuring a flying height from a support surface, and particularly relates to a flying height measuring device that can accurately determine a flying height without being affected by vibrations or the like.

(Prior Art) When conveying a film made of polyester or the like along a conveyance line, it may be necessary to measure the flying height of the film from the surface of a support. Furthermore, when the film is transported while being floated by air, it is especially necessary to measure the flying height.

The flying height of the film is determined by first making a laser beam enter a predetermined position on the conveyance path from an oblique direction and reflecting it on the film support surface of the support body, and then making the reflected light enter a displacement detector and directing it to the incident position. based on the reference position of the support surface, and then, when the film passes the predetermined position, the laser beam is irradiated again to cause the reflected light on the film surface to enter the displacement detector, It is determined by detecting the film surface position based on the incident position and further subtracting the predetermined film thickness from the difference between the detected film surface position and the reference position.

(Problem to be Solved by the Invention) However, when the film is opaque, most of the laser light incident on the film is reflected on the film surface, so the measurement is performed well. When the film is opaque, when the laser beam is incident on the film, the amount of light that passes through the film and is reflected on the support surface is greater than the amount of light that is reflected on the film surface. Since the displacement detector described above detects only the incident position of the strongest light, it becomes difficult to measure the flying height using the above method.

Furthermore, - lastly, the above method has the disadvantage that when measuring the position of the film surface, if the position of the support body or the displacement detector changes due to vibration etc., it becomes impossible to accurately measure the flying height. was.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a flying height measuring device that can satisfactorily measure the flying height of a transparent film from a supporting surface without being affected by vibrations, etc. The purpose is to

(Means and Effects for Solving the Problems) The flying height measuring device for a transparent film of the present invention includes a laser light source that makes a laser beam incident on the transparent film from a direction non-perpendicular to the film surface; A first reflected light reflected on the film surface and a second reflected light of the laser light that is transmitted through the transparent film and reflected on the support surface are incident simultaneously to detect the distance of the re-reflected light. a detection means, a memory for storing the distance detected by the light detection means on the transparent film whose flying height is determined in advance or the transparent film at a position desired to be the reference flying height as a standard value; The present invention is characterized by comprising a calculation unit that calculates the flying height of each transparent film based on the reference value and the distance detected by the light detection means for each transparent film.

According to the present invention, by using the light detection means that simultaneously detects the first reflected light on the transparent film and the second reflected light on the support surface and measures the distance between them, Even if the first reflected light is weaker than the second reflected light, the re-reflected light can be detected favorably and the flying height of the transparent film can be determined based on the detected value. Furthermore, since the re-reflected light is simultaneously detected by the light detection means, even if the positions of the support surface and the light detection means change due to vibrations, etc., the relative positional relationship between the support surface and the transparent film will be maintained. can be measured correctly.

Further, when the reference value is detected based on the transparent film whose flying height has been determined in advance, the flying height of each transparent film to be measured calculated in the calculation section is calculated from the support surface. If the reference value is detected based on the transparent film at the position where the reference flying height is desired, the flying height of each film calculated in the calculation unit is the absolute value of the flying height from the This is a relative value to the reference l increase amount. Therefore, if you want to find the absolute value of the flying height for each transparent film, you can use the former method, or if you want to find the deviation of each transparent film from the position you want to use as the reference flying height. You can use the latter method.

Note that the flying height of the transparent film can be determined by combining the first reflected light on the transparent film whose flying height is to be measured and the above-mentioned without using the previously determined flying height or reference flying position and the reference value. It is also possible to calculate based only on the distance of the second reflected light, but in that case,
Data such as the refraction angle of the laser beam within the transparent film, the thickness of the transparent film, the refractive index of the transparent film, and the refractive index of the outside of the film are required, making the calculation complicated. In contrast, in the present invention, the distance between the two reflected lights described above at a predetermined flying height is determined in advance as a reference value, and the calculation is performed using this reference value, making the calculation extremely easy. It can be made simple.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram of a flying height measuring device for a transparent film according to an embodiment of the present invention.

This measuring device measures the flying height from the support surface 1a of a transparent film 2 made of polyester or the like, which is placed on a metal support 1 whose support surface 1a is mirror-finished.

A laser light source 3 is disposed above the transparent film 2, and this laser light source 3 makes laser light 4 incident on the transparent film 2 from an oblique direction.

Further, on the optical path of the laser beam 4, an optical system 7 is arranged to focus the laser beam near the surface 2a of the transparent film 2. A portion of the laser beam 4 incident on the surface 2a of the transparent film 2 is reflected by the surface 2a to become first reflected light 4a, and the remaining light is transmitted through the transparent film 2.

Most of the transmitted light is reflected on the support surface la, and most of the reflected light passes through the transparent film 2 again and is emitted as second reflected light 4b. A light detection means 5 is provided at a position receiving the first and second reflected lights 4a and 4b.
are arranged, and the two incident reflected lights 4a, 4b
It is designed to measure the distance between. That is, the light detecting means 5 of this embodiment is equipped with, for example, a microscope lens or the like to obtain a sufficient magnification.
It has a built-in V left camera, which separates and detects the reflected lights 4a and 4b in the TV left camera output signal, and measures the distances 9 and 1 between both reflected lights 4a and 4b. The distance measured9. The information on s is input manually to the calculation unit 6, and the calculation unit 6 uses the distance 9Js to calculate the floating Jixl of the transparent film 2 as described later.

By the way, in this measuring device, prior to detecting the floating height mx1, a transparent film 2 whose flying height has been measured in advance is used.
'The first reflected light 421' and the second reflected light 4b at
'The distance force 1 [is determined. In this embodiment, the transparent film 2' is stopped on the support 1 and has a floating amount of zero.

It goes without saying that the transparent film 2' has the same abrasive quality and thickness as the transparent film 2 on which the normal flying height measurement is performed. The distance between the first reflected light 4a' and the second reflected light 4b' in the transparent film 2' whose flying height is zero is zero as shown in FIG. This distance is temporarily stored in the memo January 0 as a reference value 9Jo.

Regarding the detection of the flying height X1 of each transparent film based on the distance reference value Min0 stored in the memo January 0 and the distance 9Js detected for each transparent film 2, please refer to FIG. I will explain in detail.

As shown in FIG. 2, in the photodetecting means 5,
the two reflected lights 4a based on the TV left camera output;
4b, the center of gravity is calculated, and the distance f between the two points is determined by the positions of the two centers of gravity.
'l is required. The obtained value of the distance division 1 is sent to the calculation section 6.

On the other hand, this calculation unit 6 stores the distance between two points when the flying height is zero from the aforementioned reference value from the memory 10.

This standard value is exempt.

and the distance reading outputted from the light detection means 5! The floating height mx1 is calculated using the above. That is, as shown in FIG.
When the incident angle of is θ, the flying height xl is A in FIG.
AA' -2 by the distance AA' between the two points indicated by A'
Since Xx1 tanθ, Qrl-9Jo -AA
'cos θ=2x1 sin θ holds true. Also, since the incident angle θ can be set to a constant value, the above levitation mXl is exempted! It can be found by and 0. In addition, in this embodiment, since the reference value of the flying height is zero, the flying height mx of the transparent film 2
1 is equal to the distance from the transparent film 2' at the reference position to the transparent film 2 to be measured, but if the reference flying height is not zero, it can be calculated using the above equation (1). The value obtained by adding the flying height of the transparent film as a reference to the flying height obtained is the flying height to be determined.

As described above, according to the present measurement method, the above-mentioned two reflected lights 4a and 4b are detected simultaneously and the distance between them is measured, so that the reflected light 4 on the film surface 2a is
Even if a is weaker than the reflected light 4b on the support surface Ia, the flying height xl can be detected satisfactorily based on the distance Lx between both reflected lights. In addition, since the distance flx corresponds to the relative position between the support 1 and the transparent film 2, even if the position of the support 1 changes from a predetermined position due to vibration or the like, it will not be affected by the change. The floating mx1 can be detected without being affected. Furthermore, in the apparatus of the present invention, the distance between the two reflected lights on the transparent film 2' whose flying height is determined in advance is stored in the memory as a reference value minus 0, and this reference value is used to Since the flying height of each transparent film 2 is calculated, the floating titxt can be measured by extremely simple calculations without using data such as the refractive index and thickness of the transparent film 2.

Note that the absolute value of the flying height of the transparent film 2' used as a reference does not necessarily have to be determined, but the two reflected lights on the transparent film 2' at a predetermined position where the reference flying height is desired to be determined. The distance is detected, and the value of this distance 9Jo and the above-mentioned distance in each transparent film 2 are calculated. By using the value of , it may be possible to detect how far each transparent film 2 is deviated up and down from the position where the reference flying height is desired.

Furthermore, the light detection means 5 does not necessarily have to be equipped with a TV camera, but may be equipped with a CCD or a one-dimensional light-receiving element array. Further, the two reflected lights 4a and 4b do not necessarily need to be made perpendicularly incident on the photodetecting means 5, and both reflected lights 4a and 4b may be made incident on the photodetecting means 5 from an oblique direction. In that case, the distance between the two reflected lights 4a and 4b may be calculated from the distance between the incident positions of the two reflected lights 4a and 4b on the light detection means 5.

(Effects of the Invention) As explained above, according to the method and apparatus for measuring the flying height of a transparent film of the present invention, the light reflected on the surface of the transparent film and the surface of the support is simultaneously detected by the photodetector, and both reflected light is detected simultaneously. The flying height of the transparent film can always be calculated accurately without being affected by vibrations, etc.
1 can be determined.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a flying height measurement device for a transparent film according to an embodiment of the present invention, and FIG. 2 is a block diagram for explaining the detection of the flying height based on the 411 constant of the distance between two reflected lights. . 1...Support body 1a...Support surface 2, 2
'...Transparent film 2a...Surface 3...Laser light source 4...Laser light 4a, 4a'...
First reflected light 4b, 4b'...Second reflected light 5...Light detection means 10...Memory 6...Arithmetic unit

Claims (1)

[Scope of Claim] A transparent film flying height measuring device for measuring the flying height of a transparent film disposed on a mirror-treated opaque support surface from the support surface, comprising: a laser light source that enters a laser beam from a direction non-perpendicular to the laser beam; a first reflected beam of the laser beam that is reflected on the film surface; and a first reflected beam of the laser beam that is transmitted through the transparent film and reflected on the support surface; a light detection means for detecting the distance between the two reflected lights by simultaneously making the second reflected light incident thereon; and the light detection means on the transparent film whose flying height is determined in advance or on the transparent film at a position where the reference flying height is desired. a memory for storing the distance detected by the means as a reference value, and calculating the flying height of each transparent film based on the reference value and the distance detected by the light detection means for each transparent film. What is claimed is: 1. A flying height measurement device for a transparent film, characterized in that it is equipped with a calculation section that performs the following steps.