JPS60135843A - Method and apparatus for surface identification - Google Patents

Abstract

PURPOSE:To identify the surface and back instantaneously without damaging a tape or the like by irradiating a specified light on two surfaces of a tape or the like to compare the reflectance of reflected light from one surface with that of reflected light from the other surface. CONSTITUTION:Infrared rays from infrared ray sources 12 and 14 are irradiated on one surface 10a and the other surface 10b of a tape 10 through waveguides 16 and 18 respectively while light choppers 20 and 22 are energized to interrupt the infrared rays at a specified frequency. These rays are reflected on the surfaces 10a and 10b of the tape 10 according to respective optical characteristics at a different reflectance and introduced into detectors 24 and 26 through waveguides 28 and 30 and filters 32 and 34. As a result, the detectors 24 and 26 generate detection signals corresponding to the characteristics of the respective surfaces 10a and 10b while increasing or decreasing at a specified frequency. These signals are compared with a comparator circuit 36 and the results of the comparison indicates which is the magnetic film surface or the base surface on a display 38.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an identification method and apparatus for distinguishing between the front and back of a plate-like object, such as a magnetic tape, which is difficult to distinguish visually, and more particularly, The present invention relates to an identification method and device for optically distinguishing between the front and back surfaces of an object.

For example, magnetic tapes housed in cassettes are widely used to easily record various types of information. In this case, the magnetic film surface of the magnetic tape must be exposed to the outside in order to input and output information by bringing the magnetic film surface into direct contact with the magnetic head. Therefore, when loading magnetic tape into a cassette! This is a synthetic tree on the magnetic film surface and the opposite side!
It is necessary to clearly distinguish the u--space plane. Such identification has been simply performed with the naked eye.

Incidentally, in recent years, a method of mirror-finishing the magnetic film surface has been adopted in order to further increase the recording density of the magnetic tape and to improve the contact between the magnetic tape and the head for reliable information input and output. This mirror finish made it difficult to distinguish the synthetic resin base surface and the magnetic film surface with the naked eye.

Therefore, methods using magnetic heads, mechanical peeling methods, dissolution methods using chemicals, etc. are currently used to identify the front and back sides of such magnetic tapes. Among these methods, methods using magnetic heads are This method compares the recording and reproducing characteristics of both sides of a magnetic tape to identify the front and back sides.However, in the second method, the tape surface must be brought into contact with the head during identification, which may sometimes damage the tape surface. On the other hand, in the mechanical peeling method, the tape surface is scraped with a blade such as a razor, and in the case of a magnetic film surface, the magnetic 5 film is easily peeled off. The front and back sides are identified by taking advantage of the fact that peeling does not occur.Also, there are chemical melting methods in which a chemical such as J cyclohexanone is brought into contact with the tape surface and the front and back sides are identified by the state of dissolution.However, these methods Peeling and dissolving methods are destructive identification methods that damage the tape surface, and tape splice editing etc. damage the tape itself, which stores the necessary information, making it difficult to use for measurement. □.

Therefore, as a result of intensive study and trial production, the inventors of the present invention found that, for example, in infrared light with a wavelength of about 3 to 30 microns, there is a clear difference in the reflectance between the magnetic film surface of the tape and the island-opposite surface. It was discovered that by electrically extracting this difference in reflectance, it was possible to easily identify the front and back sides of the magnetic tape.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a non-contact identification method and device that instantly identifies the front and back sides of a tape or the like without damaging the tape.

In order to achieve this object, the method according to the present invention irradiates a predetermined light onto an object to be identified that has at least two surfaces having different light reflectances, detects the reflected light from the object to be identified, and detects the reflected light from the object to be identified. the reflectance of the reflected light from one surface of the object to be identified;
The present invention is characterized in that the surface of the object to be identified is determined by comparing the reflectance of light reflected from the other surface.

Furthermore, the device of the present invention includes a light source that irradiates a predetermined light onto the surface of the object to be identified, which includes two surfaces having different reflectances;
a detector that detects reflected light of the predetermined light from the surface of the object to be identified and generates a signal corresponding to the intensity of the reflected light;
A first signal corresponding to the reflected light intensity of the reflected light from one of the two surfaces is compared with a second signal corresponding to the reflected light intensity of the reflected light from the other of the two surfaces. Accordingly, one of the two surfaces can be identified.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the method of the present invention in relation to an apparatus for carrying out the method will be described in detail with reference to the accompanying drawings.

First, FIG. 1 shows, as an example, reflectance curves of the magnetic film surface and synthetic resin base surface of a magnetic tape with respect to infrared light irradiation.

In this case, curve A shows the reflection spectrum of the magnetic surface of the metal tape, curve B shows the reflection spectrum of the magnetic surface of the iron oxide tape, and curve C shows the reflection spectrum of the base surface of the tape. As can be seen from FIG. 1, the reflectance of the magnetic surface is clearly higher than that of the hexagonal surface in the infrared rays of wavelengths 3 to 30 microns.

This is due to the infrared absorption and multiple reflection effects of the polyester film that constitutes the base surface of the tape.

In another example, the magnitude relationship of the infrared reflectance between the base surface and the magnetic surface may be opposite to the example shown in Figure 1, but in any case, there is a clear difference in the reflectance between the front and back surfaces. There is.

Therefore, one embodiment of the present invention is shown in FIG. 2 based on the above experimental results. In the figure, reference numeral 10 indicates a magnetic tape, and a first infrared light source 12 and a second infrared light source 14 are provided on both sides of the magnetic tape 10. These first infrared light source 12 and second infrared light source 14 are equipped with, for example, nichrome wire heaters 12a and 14a, and are capable of emitting infrared light from respective openings 12b and 14b. Light transmission optical waveguides 16.1 are provided between the first infrared light source 12 and one surface 10a of the tape 10 and between the second infrared light source 14 and the other surface 10b of the tape 10, respectively.
8 are arranged. It is preferable that these waveguides 16 and 18 be constructed of, for example, a hollow metal pipe or a dielectric optical fiber for infrared light.

Furthermore, optical choppers 20.22 are inserted between the waveguides 16.18 and the light sources 12.14, respectively. Next, the first infrared photodetector 24 is applied to one side 10a of the tape 10.
A first light-receiving waveguide 28 is provided between this one surface 10a and the first infrared photodetector 24. Similarly, a second infrared light detector 26 is disposed on the other surface 10b of the tape 10, and a second light receiving detector is disposed between the other surface 10b and the second infrared light detector 26. A waveguide 30 is interposed. Further, spectral filters 32, 34 are inserted between the waveguides 28, 30 and the infrared photodetectors 24, 26, respectively. These light-receiving waveguides 28.30 are also constructed of hollow metal pipes, etc., similarly to the light-transmitting waveguides 16.18. Said detector 24.2
6 is constituted by, for example, a pyroelectric detector. in this case,
The output sides of the detectors 24 and 26 are electrically connected to a comparison circuit 36, and the output side of the comparison circuit 36 is connected to a display 38.

Next, an example of a specific configuration of the comparison circuit 36 shown in FIG. 2 will be described with reference to FIG. The output sides of the first detector 24 and the second detector 26 are each provided with a band filter 40.4.
2 to the peak hold circuit 44.46.

The output sides of these peak hold circuits 44 and 46 are connected to the input side of a comparator 48, and the output side of this comparator 48 is connected to the display 38.

Next, the operation of the apparatus shown in FIG. 2 will be explained.

First, the infrared light source 12.14 is activated, and infrared light is emitted from the openings 12b and 14b through the waveguides 16.18, respectively, onto one side 10a and the other side 10b of the tape surface 10. . At the same time, the optical chopper 20.22 is activated to cut off the infrared light from the infrared light source 12.14 at a predetermined frequency, for example 20H2. The infrared light irradiated on the surfaces 10a and 10b of the tape 10 and intermittent at a predetermined frequency is applied to the surfaces 10a and 10b.
, 10b are reflected with different reflectances according to their respective optical properties. That is, as shown in FIG. 1, since the magnetic film surface and the base surface of the tape 10 have different infrared light reflectances, the surfaces 10a and 10b reflect different amounts of infrared light.

Infrared light reflected by surfaces 10a and 10b of tape 10 and intermittent at a predetermined period is introduced into detector 24.26 via waveguide 28.3O and filter 32.34, respectively.

In this case, if the filters 32 and 34 are configured to have band transmission characteristics that match the absorption spectrum range of the base surface, one surface 10a that passes through the filters 32 and 34,
That is, the difference in the amount of light reflected from the magnetic surface and the other surface 10b, that is, the base surface, can be made more noticeable.

In this way, two reflected infrared lights having a significant difference in light intensity due to the difference in the characteristics of the surfaces 10aS10b are introduced into the detectors 24 and 26, respectively, intermittently at a predetermined frequency. As a result, detectors 24, 26 are detected on surfaces 10a, 1, respectively.
A detection signal corresponding to the characteristics of 0b and increasing/decreasing at a predetermined frequency is generated. These signals are each passed through a bandpass filter 4O1
42, the components of the predetermined frequency are extracted, and other components are removed. Therefore, the peak hold circuits 44 and 46 into which the outputs of these bandpass filters 40 and 42 are introduced hold the peak values of the outputs and output the held values to the comparator 48.

The comparator 48 compares the pinic output values of the peak hold circuits 44 and 46, and the output of the peak hold circuit 44 connected to the first detector 24 is the output of the peak hold circuit 46 connected to the second detector 26. A logical value of 0.1 is output depending on whether the value is larger or smaller. The display 38 displays one side 10a according to the output of the comparator 48.
and the other surface lOb is the magnetic film surface and which is the base surface is displayed. That is, when the output of the comparator 48 is 1, it indicates that one surface 10a is the magnetic film surface, and when the output is 0, it indicates that the one surface 10a is the base surface.

FIG. 4 is an explanatory diagram showing an outline of another embodiment according to the present invention. In this embodiment, the same reference numerals as in the previous embodiment indicate the same components.

The infrared light source 12 includes a nichrome wire heater 12a, and irradiates infrared light onto one surface 10a of the tape 10 through an opening 12b. Detector 24 detects this reflected light and generates a signal corresponding to its intensity. The comparison circuit 36 is connected to the detector 24
The value of the signal corresponding to the intensity of the reflected light from one surface is held.

At this point, the tape 10 is turned over, and the other side 10b of the tape is irradiated with infrared light in the same manner as described above. Detector 24 therefore generates a signal corresponding to the intensity of the reflected light from the other facing surface. The comparison circuit 36 compares the already held value of the signal corresponding to the intensity of the reflected light from the one surface with the signal corresponding to the intensity of the reflected light from the other surface 10b, and outputs the result to the display 38. . Display 38 displays this result. "FIG. 5 is an explanatory diagram showing an outline of another embodiment of the present invention.

In this embodiment, an infrared light source 12 is disposed on the side of one surface 10g of the magnetic tape 10. The infrared light source 12 includes, for example, a nichrome wire heater 12a;
A concave mirror 50 is provided opposite b. This concave mirror 50
An optical chopper 20 is inserted into the optical path connecting the tape 10 and one surface 10a of the tape 10. Furthermore, one side 1 of the tape 10
A second concave mirror 52 is disposed facing the optical path of the reflected light from Oa, and the optical filter 32 is inserted into the optical path of the reflected light. An infrared light detector 2 is located at the condensing point of the second concave mirror 52.
4 is provided, the output side of which is connected to the comparator circuit 36,
Further, the output side of the comparison circuit 36 is connected to a display 38.

Therefore, FIG. 6 shows a specific configuration of the comparison circuit 36 of FIG. 5. The output side of the detector 24 is connected to a switch circuit 60 via a bandpass filter 54, a full-wave rectifier circuit 56, and an integrator circuit 58.
is connected to. The switch circuit has two output ends, each of which is connected to a first peak hold circuit 62 and a second peak hold circuit 64. The outputs of these peak hold circuits 62 and 64 are input to a comparator 66. The output side of this comparator 66 is connected to the display 3B.

Next, the operation of the apparatus shown in FIG. 5 will be explained.

The infrared light irradiated from the opening 12b of the light source 12 is efficiently focused by the concave mirror 50 and directed to one surface 10 of the tape 10.
irradiated to a. At that time, the optical chopper 20
Infrared light is transmitted from zero to one side of the tape 10 intermittently at a predetermined frequency. Therefore, one surface 10a of the tape 10 is irradiated with infrared light that is intermittent at a predetermined frequency. The irradiated infrared light is partially absorbed and partially reflected according to the optical characteristics of one surface 10a. That is, when one surface 10a is a magnetic film surface, the reflectance is relatively high,
On the other hand, in the case of a base surface, each infrared light is reflected with a relatively low reflectance. As a result, one side 10 of the tape 10
Infrared light having an intensity corresponding to the characteristic of a and intermittent at a predetermined frequency is reflected. This reflected light is efficiently collected by the second concave mirror 52 and introduced into the detector 24 . At this time, the filter 32 provided between the tape surface 10a and the concave mirror 52 absorbs light outside the absorption spectrum range of the base surface of the tape 10, thereby reducing the amount of reflected light due to the difference in optical characteristics of the tape surface 10a. Make the difference in strength more noticeable.

The detector 24 generates a signal that increases or decreases at a predetermined frequency in response to the intensity of the infrared light introduced by the concave mirror 52, and outputs it to the bandpass filter 54 in the comparison circuit 36. The bandpass filter 54 extracts the predetermined frequency component and removes noise components based on light other than the reflected light from one surface 10a of the infrared light from the light source 12. The full-wave rectifier 56 performs full-wave rectification on the frequency component output from the bandpass filter 54 and outputs it to the integrating circuit 58 . This integrating circuit 58 integrates the output of the full-wave rectifier circuit 56 over time and outputs the integrated value to the switch circuit 60. Switch circuit 60 transmits the output of predetermined time integration circuit 58 to first peak hold circuit 62 . Therefore, the first peak hold circuit 62 has the predetermined time and one side 1 of the full wave rectifier circuit 56 within the predetermined time.
A value corresponding to the product of the output based on 0a and the average value is held.

Next, the tape 10 is turned over, and the light source 1 is placed on the second side 10b.
Irradiate infrared light from 2. The operation in this case is also omitted because the steps up to the integrating circuit 58 are exactly the same as in the above case. Therefore, in this case, the output of the integrating circuit 58 corresponds to the optical characteristics of the other surface lOb, that is, the reflectance of infrared light. The switch circuit 64 transmits the output of the integrating circuit 58 to the second peak hold circuit 64 for a predetermined period of time. Therefore, the second peak hold circuit 64 holds a value corresponding to the product of the predetermined time and the average value of the output based on the other surface 10b of the full-wave rectifier circuit 56 within this predetermined time.

The comparator 66 compares the outputs of the first peak hold circuit 62 and the second peak hold circuit 64, and outputs a logical value l when the former is larger than the latter, and outputs a logical value O when the opposite is the case. . The display 38 indicates that one side 10a of the tape 10 is a magnetic surface when the output of the comparator 66 is 1, and conversely, when the output of the comparator 66 is 00.
Sometimes it is indicated that the other surface 10b is the base surface.

As described above, the present invention utilizes the difference in reflectance of infrared light to identify the front and back sides of the magnetic tape surface by comparing the difference in intensity of reflected light. Therefore, even if the front and back sides of the tape are difficult to see with the naked eye, it is possible to instantly identify them without contact. Furthermore, since it is possible to identify the front and back sides of the magnetic tape surface in real time, it is effective for online inspection on production lines and the like. Furthermore, the infrared light is modulated at a certain period, and the corresponding frequency component is extracted from the detection signal.
Further, by transmitting the reflected light through a filter whose absorption spectrum range and transmission range of the base surface are different from each other, excellent effects such as extremely reliable identification can be obtained.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments. Of course, various improvements and design changes can be made without departing from the gist of the present invention.

[Brief explanation of drawings]

FIG. 1 is a curve showing the reflectance of the magnetic tape surface, that is, the reflected light spectrum. FIG. 2 is an explanatory diagram showing the outline of the configuration of an apparatus according to an embodiment of the present invention. FIG. 4 is an explanatory diagram showing the outline of the configuration of the device of another embodiment, FIG. 5 is an explanatory diagram showing the outline of the configuration of the device of still another embodiment, and FIG. 5 is a block diagram showing the electrical circuitry of the device of FIG. 5; FIG. 1O...Magnetic tape 12.14...Infrared light source 16.1
8... Optical waveguide 20.22... Optical chopper 24.26
・・Detector 28.3O・・Optical waveguide 32.34・・Spectral filter 36・・Comparison circuit 38・・Display device 40.42・・Band filter 44.46・・Peak hold circuit 48・・Comparator 50.52 ...Concave mirror 54...
Bandpass filter 56...Full wave rectifier 58...Integrator circuit
60... Switch circuit 62. 64... Peak hold circuit 66... Comparator patent applicant Ryowa Electronics Co., Ltd. Fig, 1 Fig, 2

Claims (1)

[Scope of Claims] (1) A predetermined light is irradiated onto an object to be identified that has at least two surfaces with different light reflectances, the reflected light from the object is detected, and one of the surfaces of the object to be identified is A surface identification method characterized in that the surface of the object to be identified is discriminated by comparing the reflectance of the reflected light from one surface with the reflectance of the reflected light from the other surface. (2. In the method described in claim 1, the predetermined light is an infrared light. a light source that irradiates light; and a detector that detects the reflected light of the predetermined light from the surface of the object to be identified and generates a signal corresponding to the intensity of the reflected light; By comparing a first signal corresponding to the reflected light intensity of the reflected light and a second signal corresponding to the reflected light intensity of the reflected light from the other surface of the two surfaces, one of the two surfaces is detected. A surface identification device configured to identify one side. (4) In the device according to claim 3, the light source is an infrared light source that generates infrared light. (5) In the device according to claim 4, a bandpass filter that transmits a spectral band in which the difference in infrared light reflectance between two surfaces of an object to be identified is significant is irradiated with infrared light. (6) In the device according to claim 4, the infrared light emitted by the infrared light source is guided to the surface of the object to be identified. A surface identification device comprising an optical waveguide and an optical waveguide that guides reflected light from the surface to a detector. (7) The device according to claim 4, further comprising: one of the two surfaces of the object to be identified, comprising means for increasing or decreasing the amount of light at a predetermined period, and a bandpass filter for extracting a frequency component of the predetermined period from a signal corresponding to the intensity of reflected light generated by the detector; one of the two surfaces by comparing the frequency component extracted from the signal based on the reflected light from the surface with the frequency component extracted from the signal based on the reflected light from the other surface of the two surfaces. (8) The device according to claim 7, further comprising: a rectifying circuit for rectifying the frequency component extracted by the bandpass filter; and integrating the output of the rectifying circuit. Equipped with an integrating circuit,
Comparing the output of the integrating circuit resulting from the reflected light from one of the two surfaces of the object to be identified with the output of the integrating circuit resulting from the reflected light from the other of the two surfaces. A surface identification device for identifying one side of the two surfaces from the other. (9) In the device according to any one of claims 4 to 8, a first infrared light source that irradiates infrared light onto one of two surfaces having different infrared light reflectance; , a second infrared light source that simultaneously irradiates infrared light onto the other side of the two surfaces, and a first signal that detects reflected light from the one surface and generates a first signal corresponding to the intensity of the reflected light. comparing the first and second signals with a second detector that detects reflected light from the other surface and generates a second signal corresponding to the intensity of the reflected light; A surface identification device comprising a comparison circuit.