JPS63255807A - Composite thin film magnetic head - Google Patents

Abstract

PURPOSE:To attain the recording and reproducing of an information signal except an image signal by forming the gap part of a magnetic head at the position away from the central line of a magnetic head in a track width direction. CONSTITUTION:The head is equipped with magnetic heads 10 and 20 for an image signal and a magnetic head 20 for a sound signal which forms the azimuth of an angle theta with the magnetic heads 10 and 20 for the image signal and adjoins with the magnetic heads 10 and 20 for the image signal in a track width Tw direction. Magnetic heads 10, 20 and 30 are thin film magnetic heads and respective heads slide and connect insulating layer gap parts 13a, 23a and 33a sandwiched by upper part magnetic layers 11, 21 and 31 and lower part magnetic layers 12, 22 and 32 to a flexible magnetic recording disk. Here the gap part 33a is formed at the position away from the central line of the magnetic head 30 for the sound signal in a track width direction. Thus, with a satisfactory head touch, the image signal and the sound signal can be recorded and reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic head for recording and reproducing signals on a rotating flexible magnetic recording disk, and more particularly, the present invention relates to a magnetic head for recording and reproducing signals on a rotating flexible magnetic recording disk. The present invention relates to a composite magnetic head capable of recording and reproducing information signals other than image signals such as music.

(Prior art) A magnetic recording/reproducing device using a flexible magnetic recording disk as a recording medium rotates a flexible magnetic recording disk on which image signals have been recorded in advance, and then freezes the image signals recorded thereon. Still image playback devices that reproduce images on display devices such as television receivers, and convert images of objects obtained through a lens into electrical signals and record them on flexible magnetic recording disks to receive still images on television. So-called electronic still camera devices, etc., which reproduce images on display devices such as cameras, have been developed.

In these magnetic recording devices and reproducing devices, the image signal is recorded for one field per round of the annular track. This method of reproducing one still image using one field of image signals is called field recording and reproduction. Furthermore, a method in which one field of the same frame is recorded on two annular tracks, one frame is composed of image signals from the two annular tracks, and one still image is reproduced is called frame recording and playback. . That is, frame recording and reproduction requires twice as many annular tracks as field recording and reproduction, and the number of still images that can be recorded on a flexible magnetic recording disk is halved. Also, these circular tracks usually have 40
They are formed in a concentric ring shape with a gap (guard band) on the order of μm.

(Problems to be Solved by the Invention) By the way, when displaying still images on a television receiver or the like, there is a strong demand for simultaneously outputting audio, music, etc. corresponding to the image signal.

In response to the above request, information signals other than image signals such as audio are temporally compressed and recorded on a part of the annular track conventionally used for image signals, and the information signals are compressed in time and recorded. A method has been proposed in which the audio signal is expanded and played back, but such a method not only causes the inconvenience that the number of tracks for image signals decreases by the number of tracks allocated for recording information signals, but also However, a means for determining whether the signal recorded on the track is an image signal or another information signal such as audio is required, making the apparatus complicated and expensive.

In addition, in order to prevent the number of tracks for image signals from decreasing, information signals are recorded in gaps separating each annular track, so-called guard bands, and the information signals and image signals are recorded so as to be azimuthal to each other. A recording method has been proposed in Japanese Patent Laid-Open No. 153803/1983. However, since the magnetic head for image signals and the magnetic head for information signals are usually provided independently, it is difficult to ensure good helad touch of these magnetic heads at the same time in extremely close positions as described above. It is extremely difficult to track each magnetic head with high precision, and a complicated mechanism is required to perform tracking of each magnetic head with high precision. This results in a complicated device, resulting in an increase in size and cost. In addition, when magnetic heads are provided for image signals and information signals, the positions of both magnetic heads must be precisely adjusted, so the relative position of each head differs slightly depending on the device, and if one device is used for recording. magnetic disk,
When playing back to the other device, so-called tracking is difficult, resulting in problems such as a drop in playback output and S/N ratio, and it also becomes difficult to replace each head, resulting in virtually no compatibility. There are also serious problems.

Therefore, Japanese Patent Laid-Open No. 61-129701 discloses a device that uses a magnetic head that integrates a magnetic head for image signals and a magnetic head for information signals to record information signals on the guard band of an annular track for image signals. has been disclosed. However, the above-mentioned magnetic head has serious drawbacks as described below when used in actual use.

That is, the magnetic head has a structure in which one magnetic head for audio signals is held between a pair of magnetic heads for image signals, and both sides of the magnetic pole of the magnetic head for audio signals are the magnetic poles of the magnetic head for image signals. are close to each other on the sides and over a large area. In a magnetic head with such a structure, the magnetic coupling between adjacent magnetic heads is strong, and each signal magnetic flux leaks to the adjacent magnetic head, resulting in significant so-called crosstalk that causes noise, and the reproduced image becomes large. Problems arise in that disturbances and noise occur. Therefore, the integrated magnetic head described above is completely unsuitable for practical use, and a magnetic head that can successfully record and reproduce both image signals and information signals on a flexible magnetic recording disk has not yet been developed. is the current situation.

In view of the above problems, the present invention enables highly accurate tracking without increasing the size of the device.
We developed a magnetic head that has good head touch, avoids problems such as crosstalk, and can record and reproduce both image signals and information signals on the same disk without reducing the number of tracks for image signals. The purpose is to provide

(Means for Solving the Problem) In recent years, magnetic heads for high-density recording are constructed by laminating upper and lower magnetic layers, a conductive layer, and an insulating layer on a substrate using thin films, and a part of the conductive layer is A thin-film magnetic head has been developed in which the front surface of a gap portion sandwiched between upper and lower magnetic layers is brought into sliding contact with a recording medium. As a result of intensive research in order to achieve the above-mentioned purpose, the present applicant has developed both an image signal magnetic head and an information signal magnetic head of the @89 type, and has integrated these magnetic heads into a composite thin film magnetic head. The inventors have found that it is possible to obtain a magnetic head that satisfies all of the above objectives.

Based on the above findings, the composite thin-film magnetic head of the present invention, which was derived as a result of further research into the specific structure, etc., is the i'N! The first feature is that a first magnetic head and a second magnetic head, which are I magnetic heads, are integrally provided, and the re-magnetic heads are provided azimuthally and substantially adjacent to each other in the track width direction. A second feature is that the gap portion of the first magnetic head is formed at a position offset from the center line of the head in the track width direction of the magnetic head.

Of course, the present composite thin-film magnetic head can be used as a magnetic head for information signals by using the first magnetic head and a magnetic head for image signals, but it can also be used as a re-magnetic head for image signals. It may be used for signals, or it may be used with a remagnetic head for information signals. Further, the present composite thin film magnetic head may be a two-track magnetic head that records and reproduces image signals in the field and records and reproduces information signals such as audio on tracks adjacent to the inner or outer circumference of the image signal track. A three-track magnetic head records and reproduces the image signal in frames using two tracks, and records and reproduces the information signal in a track sandwiched between these tracks, or records and reproduces the image signal in frames,
It may be any four-track magnetic head that records and reproduces information signals on a track sandwiched between two image recording signal tracks and on a track adjacent to the inner or outer circumference of the two tracks. Furthermore, the first magnetic head and the second magnetic head are substantially adjacent in the track width direction, which means that the gap portion on the sliding surface that defines the track width is adjacent to each other on the disk to form a track. This means that the remagnetic head is disposed in a direction perpendicular to the width direction of the track. Further, the remagnetic head may be arranged so that tracks formed adjacent to each other on the disk overlap with each other, or there is a slight gap between them. Furthermore, in the remagnetic head, portions of the conductive layer and the like that are away from the sliding surface may partially overlap each other.

Furthermore, in the present invention, the first magnetic head and the second magnetic head refer to the minimum necessary magnetic head element parts for magnetic recording and reproduction, that is, the upper and lower magnetic layers, the conductor layer, and the upper and lower magnetic layers that overlap each other. It consists of an insulating layer etc. in between, and does not include a substrate or a protective plate, etc.
The gap portion of the first magnetic head is formed at a position offset from the center line of the magnetic head. Here, the center line of the magnetic head is the line shown by a two-dot chain line in FIG. 5, which will be described later. It is a line.

(Function) According to the composite thin film magnetic head configured as described above, the first
By making the first magnetic head and the second magnetic head each a thin film magnetic head, when integrating both heads, it is easy to arrange both heads at positions adjacent to each other in the track width direction in an azimuthal manner. A composite head with such a structure can significantly reduce crosstalk between heads. Further, by integrating both heads, tracking can be performed with high precision without requiring a complicated mechanism for both heads. Further, since it is relatively easy to set the relative position of the gap between both heads and the azimuth angle with high precision, compatibility can be ensured by 1q.

In addition, in order for both the first magnetic head and the second magnetic head to obtain good head touch with respect to the magnetic recording disk in the composite thin-film magnetic head having the above structure, it is necessary to
The gap portion of the first magnetic head and the gap portion of the second magnetic head are not only substantially adjacent to each other in the track width direction;
It is also necessary to avoid a large separation in the direction perpendicular to the track width. In other words, if the gap between the two magnetic heads is far apart, a stable head touch cannot be obtained, such as impact noise caused by both heads individually contacting the magnetic disk. Normally, a thin film magnetic head has a magnetic layer and a conductive layer behind the gap portion that protrude symmetrically in the track width direction with respect to the gap portion, and the first magnetic head and the first magnetic layer are arranged so as not to damage these layers. If the two magnetic heads are arranged in a relative azimuth, the gap portion of the first magnetic head and the gap portion of the second magnetic head will be far apart in the direction perpendicular to the track width. On the other hand, in the composite thin film magnetic head of the present invention, since the gap portion of the first magnetic head is formed offset from the center line in the track width direction of the magnetic head, a part of one magnetic head is formed at the gap portion. The amount of protrusion from the magnetic head toward the other magnetic head can be reduced, and it is possible to prevent the gap between the two heads from becoming too far apart in the direction perpendicular to the track width.

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

FIG. 1 is a front view showing a sliding surface of a composite film magnetic head according to an embodiment of the present invention.

This composite thin film magnetic head 50 includes two image signal magnetic heads 10 and 20, and two image signal magnetic heads 10 and 20.
The audio signal magnetic head 30 has an azimuth of 0.20 and an angle θ and is adjacent to the image signal magnetic head 10.20 in the track width 7w direction of the image signal magnetic head 10.20. The above three magnetic heads 10.
As will be described in detail later, 20 and 30 are thin film magnetic heads each formed of a thin film, each of which is an insulating layer sandwiched between an upper magnetic layer 11, 21, 31 and a lower magnetic layer 12, 22, 32. Certain gap portions 13a, 2
Recording and reproduction of image or audio signals is performed by bringing 3a and 33a into sliding contact with a flexible magnetic recording disk.

This composite thin film magnetic head 50 has a 3-track composite thin film 11! that records and reproduces image signals in frames. ! The magnetic head is a flexible magnetic recording disk 6 as shown in FIG.
0, image signals are recorded on two image signal tracks 61 and 62 of one field each by the two image signal magnetic heads 10 and 20 of the present magnetic head 50,
Between these two image signals, an audio signal track 63 is formed by the audio signal magnetic head 30 in a portion that was conventionally a guard band. Therefore, according to this composite thin film magnetic head 50, audio signals can be recorded and reproduced without reducing the number of tracks for image signals. Figure 3 below.

The details of the structure of the composite thin film magnetic head 50 will be explained based on its manufacturing process with reference to FIGS. 4 and 5.

When manufacturing the composite one-film magnetic head 50, first, as shown in FIG. 3(a), a two-track image signal magnetic head 10, 20 is formed from a thin film by a conventionally known method. 4, which is a cross-sectional view taken along line A-A in FIG. 3(a).
The method for forming the image signal magnetic head 20 will be explained with reference to the drawings. First, the lower magnetic layer 22 is formed on a substrate 24 made of magnetic ferrite by sputtering sendust alloy.

Next, SiO2, which is an insulating material, and Cu, which is a coil material, are appropriately formed on this lower magnetic layer 22 by a known method, and etched by etching or the like to form an insulating layer 23 and a two-layer coil as shown in the figure. A conductor 25 is formed. Next, on top of these W4 layers, Sendust alloy is further deposited by sputtering or the like in the same way as the lower magnetic layer 22, to form the upper magnetic layer 21. Furthermore, a protective layer 26 is formed above this by SiO2 sputtering. This protective layer 26 is polished and planarized to the position shown by the dashed line in FIG. Note that the portion of the insulating layer 23 sandwiched between the upper magnetic layer 21 and the lower magnetic layer 22 becomes the gap portion 23a. The other image signal magnetic head 10 has the lower magnetic layer 2 on the same substrate as the image signal magnetic head 20.
After the lower magnetic layer 12 is formed integrally with the lower magnetic layer 2, it is formed in exactly the same process. Note that in this embodiment, the coil conductors 15. of the two image signal magnetic heads 10 and 20.
25 is a gap portion 13a in the track width direction as shown by the broken line in FIG.

It is formed to protrude to both sides of 23a by an approximately equal amount.

On the other hand, the audio signal magnetic head 30 is as shown in FIG. 3(b).
As shown in FIG. 2, the image signal magnetic head 10.20 is formed on a substrate 34 separate from the substrate 24 by the same procedure as the image signal magnetic head 10.20 described above, but the shape and arrangement of each layer are the same as the image signal magnetic head 10.20. 20, the gap portion 33a is formed at a position offset from the center line of the audio signal magnetic head 30 in the track width direction. The details of the structure of this audio signal magnetic head 30 are shown in FIG. 5, which is a schematic plan view of the head.

FIG. 5 shows only the coil conductors 35A and 35B of the upper magnetic layer 31, the lower magnetic layer 32, and the second layer provided on the substrate. The audio signal magnetic head 30 includes an upper magnetic layer 3
1. A portion of the lower magnetic layer 32 overlapping the upper magnetic layer 31, the coil conductors 35A, 3581, and the upper and lower magnetic layers 31
．． An insulating layer provided between 32 (not shown in FIG. 5)
The length in the track width direction is defined by the coil conductors 35A and 35B. Further, the position of the gap portion 33a is defined by the position of the portion near the sliding surface of the upper magnetic layer 11131 (the upper end in the figure). In this embodiment, the upper magnetic layer 31 is formed biased toward one end (right side in the figure) of the audio signal magnetic head in the track width direction 7w, and the coil conductors 35A and 35B are formed at the other end (in the figure) in the track width direction. It protrudes only on the left side). As shown in FIG. 3(b), such an audio signal magnetic head 30 is constructed by laminating a protective layer 36 on top and flattening it, and then applying an adhesive 37 such as low-melting point glass on the protective layer 26. A protective plate 38 made of non-magnetic ferrite is adhered to form a magnetic head block 39 for audio signals.

This block 39 is then cut diagonally with respect to the substrate 34 at a position indicated by a chain line in the figure to form a bonding surface 39a. Note that the angle θ between the bonding surface 39a and the substrate 34 determines the relative azimuth angle between the information signal magnetic head 30 and the image signal magnetic head. After the audio signal magnetic head block 39 is further cut as required, its joint surface 39a is attached to the two-track image signal magnetic head 10, as shown in FIG.
．． 20 and is bonded with an adhesive 40 such as low melting point glass. The composite thin film magnetic head 50 thus obtained is completed by subjecting the sliding surface to processing as required.

By the way, in the composite thin film magnetic head 50 completed in this way, in order for both the two image signal magnetic heads 10 and 20 and the audio signal magnetic head 30 to obtain good head contact with the magnetic recording disk. In order to achieve this, it is necessary to bring the gap between the audio signal magnetic head and the image signal magnetic head close to each other in the direction perpendicular to the track width direction (the L direction in FIG. 3(C)). The position of the audio signal magnetic head 30 in the above direction changes depending on the cutting position when creating the cut surface 39a. Therefore, in FIG. 3(b), when the audio signal magnetic head 30 is integrated, the cutting position shown by the dashed line (l is away from the gap part 33a as shown by the broken line). It is arranged at a position further away from the image signal magnetic heads 10 and 20 in the L direction.In the audio signal magnetic head 30 of this embodiment, as described above, the gap portion 33a is located at a position further away from the head in the track width direction. Since it is formed at a position offset from the center line, the gap portion 33a
Even if the area near the coil is cut, the coil conductor etc. will not be cut.

Therefore, the audio signal magnetic head 30 of this embodiment can be closely integrated with the image signal magnetic head in the direction perpendicular to the track width direction of the image signal magnetic head. Note that the sliding surface 50a of the composite thin-film magnetic head 50 is processed to have a spherical surface shape as necessary. Whether or not it should be arranged varies depending on the radius of curvature R of the sliding surface. Generally, the smaller R is, the more it is necessary to place the audio signal magnetic head close to each other, so the gap portion of the audio signal magnetic head may be formed to be largely biased from the center line of the head toward the end.

As an example, an image signal magnetic head 10 shown in FIG.
20 track width TW and audio signal magnetic head 30
The track widths Tw J of both are 60 μm, the thickness of each gap portion 13a, 23a, 33a is 0.3 μm, and the interval between the gap portions 13a, 23a of the two image signal magnetic heads is 40 μm. hand,
The azimuth angle θ is 45", and the curvature of the sliding surface processed into a spherical shape is R-17, and the radius on the sliding surface is 10".
Using a composite thin-film magnetic head in which each magnetic head is integrated so that the gap portions of all the magnetic heads are within a 0 μm circle, image signals and 10 A second audio signal was recorded and played back. FIG. 6 is a block diagram showing a circuit for recording and reproducing image signals and audio signals using the composite thin film magnetic head 50.

The still image color signal obtained from the imaging system 70 is modulated and added by FM modulators 71A and 71B, and then
The image signals are recorded on the magnetic recording disk 60 through the gate 72 by the image signal magnetic heads 10 and 20 in the three-track composite thin film magnetic head 50. On the other hand, the audio signal obtained from the microphone 80 is amplified by the amplifier 81 and then compressed to 1/60 seconds by the time axis compression circuit 82, and this compressed audio signal is sent to the composite thin film magnetic The audio signal magnetic head 30 in the head 50 records the audio signal on the aforementioned audio signal track of the magnetic recording disk 60. When reproducing an audio signal, the audio signal recorded on the magnetic recording disk 60 is also detected by the information signal magnetic head 30, is amplified by an amplifier 84, is FM demodulated by an FM demodulator 85, and is time-sampled. The axis expansion circuit 86 restores the original 10 second audio signal. This restored audio signal passes through an amplifier 87 and is output as an audio signal. The image signal recorded on the magnetic recording disk 60 is also detected by the image signal magnetic heads 10 and 20, and is displayed as a still image on a display device such as a television receiver by a well-known reproduction system (not shown). . During playback of this still image, interference from the audio signal, or crosstalk, was -44 dB, and no screen disturbance was observed. Conversely, no noise from the image signal was observed during audio playback. Furthermore, no impact noise was generated and good head touch was ensured for each magnetic head.

As described above, according to the composite thin film magnetic head of the present invention, both the magnetic head for image signals and the magnetic head for audio signals can be
By using the WIl* magnetic head, both magnetic heads can be easily formed integrally so that they are adjacent to each other in the track width direction and are azimuthal to each other. Therefore, each magnetic head can perform highly accurate tracking and can prevent crosstalk from increasing. Furthermore, since the gap portion of the audio signal magnetic head is formed at a position offset from the center line in the track width direction, the audio signal magnetic head can be placed close to the image signal magnetic head, and all The magnetic head can stably obtain good head touch.

Although the above description has been made using a three-track composite 7II film magnetic head as an example, the composite thin-film magnetic head of the present invention has three tracks adjacent to each other at an azimuth angle, as shown in FIG. 7(a). 2, which has one track of magnetic head 110 for image signals and one track of magnetic head 130 for audio signals;
It may be a composite thin film magnetic head of a track, or a seventh
As shown in Figure (b), a four-track magnetic head having two tracks of image signal magnetic heads 210 and 220 and two tracks of audio signal magnetic heads 230 and 240 may be used. In the case of an rB4-track composite thin-film magnetic head, it is possible to record audio for twice the time or to perform stereo recording compared to a 2-track or 3-track composite thin-film magnetic head. Also, each AL that makes up this composite agIta head! l! I
f! The specific materials of each layer of the magnetic head are not limited to those shown in the above embodiments, and the structure may also be such that each magnetic head has a single conductor layer or each substrate is made of a ferromagnetic material. Various changes are possible, such as giving it a function as a lower magnetic layer. In addition, the shape of the conductor layer (coil conductor) and magnetic layer of the audio signal magnetic head and the position of the gap are within the range that allows the audio signal magnetic head to be placed at a desired position close to the image signal magnetic head. It may be set arbitrarily as long as at least the gap portion is offset from the center line of the magnetic head in the track width direction. Furthermore, the gaps of both the image signal magnetic head and the audio signal magnetic head may be formed at positions offset from their respective center lines. Further, in each of the above embodiments, the case where the information signal other than the image signal is an audio signal has been explained as an example, but it goes without saying that the information signal is not limited to an audio signal, but may be music or other various information signals. stomach. In general, the head on one track is not limited to being used for image signals and the head on the other track is used for information signals, but the head on either track may be used for image signals, and the head on either track may be used for image signals. It goes without saying that both may be used for information signals other than image signals.

(Effects of the Invention) As described above in detail, according to the composite thin film magnetic head of the present invention, the first magnetic head for information signals and the second magnetic head for image signals are both formed by the thin film magnetic head. By forming and integrating with each other in azimuth,
Since no complicated mechanism is required for tracking,
Inconveniences such as an increase in the size and cost of the entire device do not occur. Further, since each head can be easily formed at a predetermined position and with a predetermined azimuth, compatibility is excellent. Furthermore, since both heads are azimuthally aligned, crosstalk can be sufficiently reduced, making it possible to use the conventional guard band between the image signal tracks as an information signal track. It becomes possible to record and reproduce information signals without reducing the number of tracks, and to reproduce images, sounds, etc. with extremely low noise.

In addition, in the present 5g5tn head, the gap portion of the first magnetic head is provided offset from the center line in the track width direction, so that when the two magnetic heads are relatively azimuthally adjacent to each other, Furthermore, both magnetic heads can be brought close to each other in the direction perpendicular to the track width direction, and good head touch can be ensured for both magnetic heads.

[Brief explanation of drawings]

Fig. 1 is a front view showing the sliding surface of a composite thin film magnetic head according to an example M of the present invention, Fig. 2 is a schematic plan view of a flexible magnetic recording disk, and Figs. 3 (a) and (b). , (c) is a perspective view illustrating the composite AMTO air head upper head shown in FIG. 1 based on its manufacturing process, FIG. A schematic plan view of a magnetic head for audio signals, FIG. 6 is a block diagram of a recording and reproducing circuit for image signals and audio signals, and FIGS. 7(a) and (b) are composite film magnetic heads according to other embodiments of the present invention. FIG. 3 is a front view showing the sliding surface of the head. 10, 20... Image signal magnetic head 11, 21.
31... Upper magnetic layer 12.22.
32 Lower part magnetic layer 13a, 23a
, 33a...Gap portion 30...Audio signal magnetic head 35Δ, 35B...Coil conductor 50...Composite thin film magnetic head 60...Flexible magnetic recording disk FIG. 2, FIG. 7 Figure 5 Figure 1, Display of the incident 1988 Patent Application No. 091.380 2, Invention title composite W1ml! Magnetic head 3, relationship with the person making the amendment case Patent applicant address 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture Name (
520) Fuji Photo Film Co., Ltd. Representative Minoru Onishi 4, Agent address 7th floor, Hauraiya Building, 5-2-1 Roppongi, Minato-ku, Tokyo Voluntary amendment 6, Subject of amendment "Detailed description of the invention" in the specification Column 7. Contents of the amendment 1) "Second" is inserted after "such" in the first line of page 10 of the specification. 2) In the fourth line of the same page, insert "of the second magnetic head" after "is a line". 3) Correct "return" to "knot" in lines 5 and 6 of the same page.

Claims (1)

[Claims] A first magnetic head for recording and reproducing a signal on an annular track on a magnetic recording disk, and a second magnetic head for recording and reproducing a signal other than the signal on an annular track adjacent to the annular track are integrally provided. , the first magnetic head and the second magnetic head each have upper and lower magnetic layers,
A thin film magnetic head in which an insulating layer and a conductive layer are formed of thin films, and the front surface of a gap portion sandwiched between the upper and lower magnetic layers slides into contact with the magnetic recording disk, and the heads are substantially adjacent to each other in the track width direction in an azimuthal manner. A composite thin-film magnetic head characterized in that the gap portion of the first magnetic head is formed at a position offset from the center line of the magnetic head in the track width direction.