JPS606026B2 - Recording medium drive control device - Google Patents

Description

Detailed Description of the Invention The present invention relates to a drive control device for a recording medium such as a magnetic tape, and more specifically, it displaces a member by electromagnetic force generated in an electromagnetic coil, and drives the recording medium based on this displacement operation. This is a drive control device for a recording medium, which is designed to simplify the configuration of the device, and aims to provide this type of device at low cost, small and lightweight.

2. Description of the Related Art It is widely practiced to utilize electromagnetic force by a solenoid to control the drive of a recording medium such as a magnetic tape. Conventional solenoids generally consist of a coil to generate supermagnetic force, a yoke placed around the coil to increase magnetic flux density, and a movable iron core to obtain mechanical output. The solenoid constructed in this way was attached to a predetermined position of the device, and the drive of the recording medium was controlled by the displacement of the movable iron core. However, the solenoid yoke occupies a space larger than the outer diameter of the coil, which has the disadvantage of making the solenoid large and hindering miniaturization of the device.Also, because the yoke has a large weight, multiple If the device utilizes only one solenoid, the device becomes very heavy, and there is also the problem that it is impossible to reduce the weight. In order to solve the drawbacks of such a secondary structure, the present invention employs a device board made of a magnetic material, and makes this device board function as a magnetic path configuration means for an electromagnetic coil.
This makes it possible to reduce the size and weight of the entire device, and one embodiment based on the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of the device, and one part of the device board is the device board, and this board 10 is made of a magnetic material such as soft iron.

One end of the magnetic tape 12 is wound around a supply reel 14, and comes into contact with a tape guide 16, an erasing head 18, a tape guide 20, and a recording/reproducing head 22, which are fixed to a substrate, respectively, and then passes through a tape drive capstan 24. It is wound around a take-up reel 26. The pinch roller 28 is rotatably supported by a shaft 32 that stands on one end of a pinch roller lever 30. A shaft 34 mounted on the substrate 10 rotatably supports a pinch roller lever 30 and a crimping bar 36 located below the pinch roller lever 30, and engages a protrusion 36a formed at one end of the crimping lever 36 with the pinch roller lever 30. One end 3 of the loaf lever 30
A torsion spring 38 is applied between the protrusion 36a and the protrusion 30a, and is normally biased so that the protrusion 36a supports the one end 30a. A tension spring 42 is stretched between the pin 40 planted on the substrate 10' and the crimping bar 36, and urges the crimping bar 36 counterclockwise so that it is always separated from the magnetic tape 10 by a mechanism to be described later. The pinch roller 28 is positioned at the position shown in FIG. 18
A switch cam 44, which has stepped portions 44a and 44b at 0 degrees opposite positions, is integrally fixed to a cam shaft 46, and a switch lever 48 that runs along its outer periphery is attached to a lever 50 that is erected on a base plate 10'. Rotatably supported, one end 48a
is applied to the actuator 52a of the normally open type microswitch 52 and says, ``From now on, it will receive a counterclockwise force.

The reel reels 14 and 26 are configured to be rotatably supported and driven by a reel stand to be described later, and a sub-board 54 shown by a broken line is arranged below the board 10. FIG. 2 shows an operation control mechanism arranged on the back side of the substrate 10.

A triangular cam 56 having a maximum radius portion 56a and a maximum radius portion 56b is integrally fixed to a cam koji 46 which is rotatably supported on the substrate 10 by a bearing (not shown). The cam follower 58, the play rack 60, the fast-forward rack 62, the rewind rack 64, the record rack 66, and the rods 68, 70, 72, and 74 are moved in the directions shown by arrows 76 and 78, respectively, with respect to the board 10 by mechanisms not shown. freely supported. The cam follower 58 has flat parts 58a and 58bb that support the triangular cam 56.
A square hole including a square hole is formed, and rack portions 58c, 58d, 58e, and 58f are formed on the end side surface, and a protrusion 58g is further formed. Differential rod 68, 70
, 72 and 74, respectively.
Pinions 88, 90, 92 and 94 are rotatably supported by pinions 4 and 86, and these pinions are meshed and engaged with rack portions 58c, 58d, 58e and 58f of the cam follower 58, respectively. play rack 60,
Rack portions 60a, 62a, 6 are provided on each side of the fast forward rack 62, rewind rack 64, and record rack 66.
4a and 66a are formed whose rack portions are adjacently engaged with pinions 88, 90, 92 and 94, respectively. The play rack 60 has holes 61 (first
A pin 60b is provided which engages with the protrusion 36b of the crimp lever 36 through the crimping lever 36 (see figure) and rotates the crimp lever 36 against the spring 42.
At the tip of the rewinding rack 64, pin protrusions 62b and 64b are formed that protrude toward the back side of the figure. Displacement levers 96, 989 100 and 102 made of soft iron
are rotatably supported by shafts 104, 106, 108 and 110 made of magnetic material such as soft iron, which are respectively raised from a substrate 101, and have stepped portions 96a, 98a, 100a and 102 at one end. Tension springs 112 and 116, each having one end fixed to the substrate 10 side, are stretched over the other ends of the displacement levers 96 and 102.
A tension spring 114 is mounted between the other ends of the displacement levers 96 and 100 in a counterclockwise direction.
Displacement levers 98 and 102 are biased to rotate clockwise. Stoppers 118 and 120 fixed to the substrate 101
, 122 and 124 are the displacement levers 96, 98, 1
00, 102, and also prevents the displacement levers 96, 9 from rotating.
8, 100 and 102 are adapted to support each other.

Magnetic cores 126, 128, 13 machined from soft iron face each of the displacement levers 96, 98, 100, and 102.
0 and 132 are fixed in pairs to the substrate 1 by means not shown. Electromagnetic coils 134, 136, 138 and 1 are attached to each core so as to surround these magnetic cores.
40 is installed. One of the two lead wires of each of these electromagnetic coils is commonly connected to the terminal 14.
2, and the remaining one each is connected to terminals 144 and 146.
, 148 and 150, respectively. The leaf switch 152 is fixed to the substrate 1 so as to be operated by the protrusion 58g of the cam follower 58, and the flat part 58aa of the cam follower 58 is connected to the maximum radius part 5 of the triangular cam 56.
6a so that its contacts close in the illustrated position. A gear 154 coaxial with the camshaft 46
is fixed integrally with the triangular cam 56. Substrate 10'
The fixed stoppers 156, 158, 160 and 162 are positioned so that the ends of the above-mentioned differential rods 68, 70, 72 and 74 can abut, respectively, while the above-mentioned stoppers 118, 120, 122 and 124 are arranged such that one ends of the racks 60, 62, 64 and 66 mentioned above can abut on each other. The arrangement of these stoppers is determined as follows. In other words, the triangular cam 56
The maximum radius portion 56a is the cam fo. Flat part 58a of A 58
When the displacement levers 96, 98, 100 and 102 are magnetically attracted and rotated by the opposing magnetic cores 126, 128, 130 and 132 in the position of the triangular cam 56 facing the Each step 96
differential rods 68, 70, 72 and 74 and racks 60, 62, 64 and 66 such that a, 98a, 100a and 102a can engage respective steps 68a, 70a, 72a and 74a of the differential rods. It is established to regulate relative positions. The above-mentioned magnetic attraction force is generated by energizing the electromagnetic coils 134, 136, 138 and 14. The mechanism of generating this attraction force will be described later. FIG. 3 shows a plan view of the reel stand drive mechanism and the triangular cam drive mechanism.

The supply reel stand 164 and the take-up reel stand 166 integrally have reel brackets 164a and 166a, respectively.
The rollers are supported rotatably on roller shafts 168 and 170, respectively. Fast forward arm 172 and rewind arm 1
74 is rotatably supported around a common shaft 176 mounted on the sub-board 54, and shafts 178 and 180 are mounted at each end. The desk feed idler 182 has a rubber-lined small-diameter step 182a and is rotatably supported on a shaft 1781, and the rewind idler 184 has a rubber-lined small-diameter step 184a and is rotatably supported on a shaft 180'. ing. The desk feed lever 18-6 and the rewind lever 188 are rotatably supported by shafts 190 and 192, respectively, which are mounted on the sub-board 54. Fast forward lever 18
A pin protrusion 186a is formed at one end of the 6, a cam surface 186b is formed at the other end, and a tension spring 196 is stretched between the remaining end and a pin 194 that stands horizontally on the sub-board 54. This fast-forwarding lever 186 is biased to rotate counterclockwise. A pin protrusion 188a is formed at one end of the rewinding lever 188, a cam surface 188b is formed at the other end, and a tension 1 imitation 200 is formed between the remaining end and a pin 198 that stands on the sub-board 54. As a result, the rewind lever 188 is urged to rotate clockwise. On the other hand, a tension spring 202 is stretched between the pin protrusion 186a and the fast-forwarding arm 172.
A tension spring 204 is also stretched between the pin protrusion 188a and the rewinding arm 174. The pin protrusion 62b of the fast forward rack 62 and the pin protrusion 64b of the rewind rack 64 in the state shown in FIG. 2 are shown in broken lines in FIG. The cam surface 186b comes into contact with the pin protrusion 62b, and the fast forward rack 62 is stopped at a position where it is in pressure contact with the stopper 120. Similarly, the rewind lever 188 receives the biasing force of the spring 200 so that the cam surface 188b comes into contact with the pin projection 62b. The rewinding rack 64 is stopped at a position where it comes into contact with the protrusion 64b and presses the rewinding rack 64 against the stopper 122.

In this state, the fast feed arm 172 receives the biasing force of the spring 202 and comes into contact with the pin protrusion 186a, and the small diameter stepped portion 182a of the fast feed idler 182 is stopped at a position away from the take-up reel stand 166. Also rewind arm 1
74 comes into contact with the pin protrusion 188a under the biasing force of the spring 204, and the small diameter stepped portion 184a of the rewinding idler 184 is stopped at a position away from the supply V-supply reel stand 164.
Next, the winding lever 206 is moved to the shaft 2 mounted on the sub-board 54.
08, and a pin 212 is hammered into one end of the pin 212 so that it can come into contact with one end 30a of the pinch roller lever 30 through a long six 210 formed on the base plate 10 (not shown). .

Further, a shaft 214 is mounted on the other end of the winding lever 206, and a relatively rotatable rubber idler 216 and a winding pulley 218 are respectively rotatably supported using this shaft 214 as a common cocoon. Note that the rubber idler 216 and the take-up pulley 218 are configured to rotate relative to each other through a predetermined friction torque using a well-known method (not shown). A tension spring 222 is tensioned between the winding bar 206 and a pin 220 that is erected on the sub-board 54, and one end 30a of the pinch roller lever 30 shown by a two-dot chain line and the pin 212 are supported. Move the take-up lever 206 to the position where
is rotated and energized counterclockwise. Tape drive motor 2
24 is fixed to the back surface of the sub-board 54, and a motor pulley 226 is fixed to an output shaft 224a protruding from the surface of this sub-board.

The tape drive capstan 24 is rotatably supported by a radial bearing (not shown) fixed to the substrate 10 (not shown) and a thrust bearing (not shown) fixed to the sub-board 54. A flywheel 228 is integrally fixed concentrically. Belt 230 is motor pulley 2
26 to the take-up pulley 218, the rapid feed idler 182,
It is stretched so as to return to the motor pulley 226 via the unwinding idler 184 and the flywheel 228. Next, the triangular cam drive mechanism will be explained.

The pulley 25 is concentrically integrated with the small gear 252 and is rotatably supported by a shaft 254 that stands on the sub-board 54. The large gear 256 and the small gear 258 are concentrically integrated, and the small gear 258 meshes with the gear 154 described in FIG.
A shaft 260 is also rotatably supported on the sub-board 54 so as to mesh with the shaft 260 . The cam drive motor 262 is fixed to the back surface of the sub-board 54, and a motor pulley 264 is fixed to an output shaft 262a protruding from the surface of this sub-board. The belt 266 connects this motor pulley 264 and the pulley 2
It is strung up between 50 and 50 meters. Here, tape drive motor 2
The relationship between the rotation of the cam drive motor 24 and the cam drive motor 262 and the displacement of each member will be briefly explained.

The tape drive motor 224 constantly rotates counterclockwise when the device power switch (not shown) is turned on,
0 in the direction of arrow 268, the tape drive capstan 24 and rewind idler 184 are rotated counterclockwise, and the fast forward idler 182 and take-up pulley 218 are rotated clockwise.The cam drive motor 262 drives the magnetic tape. It is activated by an operation control circuit (not shown) linked to a switch (not shown) to select the state and rotates counterclockwise.
The belt 266 is driven in the direction of the arrow 270 to rotationally drive the gear 254 in the direction of the rebound indicator. Therefore, the switch cam 44 in FIG. 1 and the triangular cam 56 in FIG. 2 are decelerated and rotationally driven in the counterclockwise direction. The device has the above configuration, and its operation will be explained next.

FIG. 4 shows a plan view of the apparatus in a magnetic tape reproducing state.

When the regeneration state is selected, the drive control circuit (not shown) described above energizes terminals 142 and 144 and cam drive motor 262 of FIG. 3. Therefore, the displacement lever 96
is attracted to the magnetic core 126 and rotates clockwise with respect to the ratchet 104, so that its stepped portion 96a can be mated with the stepped portion 68a of the differential rod 68, and at the same time, the triangular cam 56 and the switch cam 4
4 starts rotating counterclockwise. However, at this point, the stoppers 118 and 15 explained in FIG.
6 position is set. When the triangular cam 56 rotates, the movement of the differential rod 68 in the direction of the arrow 300 is restricted based on the engagement of the step portion 68a, so the pinion 88 rotates around the shaft 80 and the rack portion 58c of the cam follower is rotated. The displacement in the direction of arrow 300 is converted into a displacement of the rack portion 60a of the play rack 60, and the play rack 60 is driven in the direction of arrow 302. On the other hand, in parallel with this operation, the switch lever 48 moves the rigid part 44a (the first
(shown in the figure), turn it clockwise to bring the actuator 52a of the microswitch 52 to the state shown by the two-dot chain line, and turn this switch ON. Interlockingly, the leaf switch 152 is turned off.Furthermore, the triangular cam 56 rotates and the tip of the switch lever 48 falls into the step 44b of the switch cam 44, so that the actuator 52a of the microswitch 52 moves to the solid line in the figure. The leaf switch 152 returns to the position indicated by , and the switch returns to the OFF state.
When the microswitch 52 shifts from ON to OFF in the F state, it is determined that the operation for the regeneration operation has been completed, and the power to the cam drive motor 262 is cut off. When this operation is completed, the triangular cam 56 stops at a position rotated 180 degrees from the position shown in FIG. 2, and the cam follower 68 stops at a position moved in the direction of arrow 300. As the play rack 60 moves, the pin 60b presses the bar 36 and rotates clockwise against the spring 42.
The protrusion 36a is the one end 30 of the pinch roller lever 30.
By separating from a, the elasticity of the spring 38 causes a pinch load.
Lay lever 30 clockwise and pinch roller 28
is pressed against the capstan 24 with the tape 12 in between.
As the pinch roller lever 30 rotates in the clockwise direction, the pin 212 that was in contact with the one end 30a of the pinch roller lever 30 becomes movable. The rubber idler 216 is brought into rolling contact with the take-up reel stand I66.Therefore, the magnetic tape 12 is driven at a constant speed in the direction of arrow 303 by the capstan 24 and the pinch roller 28, which are rotated by the tape drive motor 224. Then, it is wound onto the take-up reel with a constant torque based on the friction torque between the take-up pulley 218 and the rubber idler 216. As the magnetic tape 12 runs, the head 22 (
(shown in FIG. 1) can reproduce the signal from the magnetic tape and cooperate with a reproduction circuit (not shown) to obtain a reproduction signal. Play rack 6 when transitioning to the playback state described above
The operation of racks other than 0 will be noted below.

As explained in FIG. 3, the fast feed rack 62 receives the biasing force of the spring 196 from the fast feed lever 186. Therefore, due to the movement of the cam follower 58, the differential rod 70 is not regulated by the displacement member 98, so it is moved in the same direction as the cam follower 58, and brought to the position shown in FIG. It remains at the position shown in Figure 2 and is not moved at all. This operation is similar to the rewinding rack 64 in FIG. 2, and the rewinding rack 64 is not displaced either.

As will be described later, the record rack 66 is also subjected to an urging force in the direction of arrow 300 in FIG. 4, so it is not displaced in the same way. As is clear from this explanation, it can be understood that racks corresponding to electromagnetic coils that are not energized with respect to the electromagnetic coils 134, 136, 138, and 140 in FIG. 2 are not displaced. The electromagnetic attractive force generated upon energization will be explained with reference to FIG. When the electromagnetic coil 134 is energized, lines of magnetic force are generated in the magnetic loop 700 shown by broken lines.

That is, the magnetic core 126, this magnetic core 126, and the displacement lever 9
6, this displacement lever 96, and the shaft 1
04, the substrate 10, and the coil holding plate 702 made of soft iron.
A magnetic loop (not shown in FIG. 2) is formed therethrough. Since the magnetic resistance of the air gap portion of this magnetic loop is reduced by the displacement lever 96 rotating in the direction of the magnetic core 126, a magnetic attraction force is generated there. As mentioned earlier, the board 10, the displacement lever 96 "Mari 104"
The magnetic cores 126 and 126 are made of solid iron, and the substrate 10 in particular has a large cross-sectional area and effectively generates the above-mentioned attractive force. The attraction force generation mechanism is the electromagnetic coils 136 and 13 during fast forwarding, rewinding, and recording operations, which will be described later.
The same applies when power is applied to 8,140, so the explanation will be omitted later.

Next, the operation when switching from the above-mentioned reproduction state to the stop state will be explained. When the stop state is selected from the play state,
The above-mentioned operation control circuit energizes the cam drive motor 262 again to rotationally drive the triangular cam 56 in FIG. The reverse operation is performed, and the pinch roller 28 and rubber tire 216 return from the state shown in FIG. 4 to the state shown in FIG. 3 or 2. Meanwhile, the switch cam 44 also returns to the state shown in FIG. When the microswitch 52 rotates 180 degrees counterclockwise from the position shown in FIG. 1 and reaches the position shown in FIG.
F, and the leaf switch 152 has turned OF before this.
The state changes from F to ON. In the operation control circuit, when the leaf switch 152 is in the ON state, the microswitch 52 is in the OFF state.
By shifting from N to OFF, it is determined that the stopping operation is complete, and the energization to the cam drive motor 262 is cut off, and at the same time, the energization to the electromagnetic coil 134 is cut off. When this stopping operation is completed, the triangular cam 56 and other members such as the rack have returned to the positions shown in FIG. 2. FIG. 5 shows a plan view of the apparatus in a fast-forwarding state of the magnetic tape.

When the fast forward state is selected from the stop state, the electromagnetic coil 13
6 is energized, and the cam drive motor 262 is also energized. Therefore, the displacement lever 98 is attracted to the magnetic core 128,
The stepped portion 98a can engage with the stepped portion 70a of the differential rod 70, and at the same time, the triangular cam 56 and the switch cam 4
4 begins to rotate counterclockwise, and as the cam follower 58 moves in the direction of arrow 78, the hishiki rod 70 similarly moves in the direction of arrow 78.
However, as described above, the displacement lever 98 stops the fast-feeding rack 62, so the pinion 901 moves the fast-feeding rack 62 in the direction of the arrow 400 and brings it to the position shown in FIG. In parallel with this operation, the microswitch 52 is turned on by the switch cam 44 and the leaf switch 152 is turned off by the cam follower 58 in the same way as at the start of the above-described regeneration operation. During the movement of the rapid feed rack 62, the pin protrusion 62b is pressed against the table feed lever 1.
86 and rotates the fast-forwarding lever 186 clockwise about the shaft 190, thereby causing the spring 2
02, the rapid feed arm 172 is similarly rotated clockwise, so that the small step portion 182 of the table feed idler 182
a is brought into contact with the winding reel table 166, and then the fast-forwarding lever 186 is rotated clockwise to release the pin protrusion 18.
6a separates from the fast-forward arm 172 and moves to the fast-forward idler 1.
82 is pressed against the winding roll stand 166 by the elastic force of the spring 202. Therefore, the take-up reel table 166 is rotated counterclockwise by the fast-forward idler 182 rotated from the tape drive motor 224 to drive the take-up reel 26.
The magnetic tape 12 is run in the direction of an arrow 402 at a faster speed than during reproduction.

In the fast-forwarding state, the microswitch 52 returns to OFF due to the rotation of the triangular cam 56, and the operation control circuit moves the microswitch 52 from ON to OFFN with the leaf switch 152 in the OFF state. It is determined that the operation is completed, and the cam drive motor 26
2, the triangular cam 66 is rotated 180 degrees from the position shown in FIG. 2, and the cam follower 58 is moved in the direction of arrow 400 and stopped at the same position as in the above-mentioned regeneration operation state. .

Even when this fast-forwarding operation is performed, the racks other than the fast-forwarding rack 62 are not displaced on the same principle of operation as described in the explanation of the reproduction operation above. The stopping of the fast-forward state is the opposite of the fast-forwarding operation, and this can be understood from the explanation of the above-mentioned stopping action of the playback state.

Next, FIG. 6 shows a plan view of the apparatus in a state in which the magnetic tape is rewound.

When the rewinding state is selected from the stopped state, the electromagnetic coil 138 is energized in this case, the differential rack 72 is locked, and the cam follower 58 The rewinding rack 64 is moved by this movement. This causes the pin protrusion 64b to move to the rewind lever 188.
is driven in the counterclockwise direction, and the small concave stepped portion 184a of the rewind idler 184 is brought into rolling contact with the supply reel stand 164. Therefore, the supply reel stand 164 and the supply reel 14 are rotated clockwise, and the magnetic tape 12 is driven in the direction of arrow 600. The transition from the rewind state to the stop is similar to the stop operation from the previous playback state or the stop operation from the fast forward state. Note that the record rack 66 shown in FIG.
A recording/reproduction changeover switch (not shown) is connected to , and an energizing force in the direction of arrow 78 is applied from this switch.

This recording/playback changeover switch moves the record rack 66 in the direction of arrow 76 to switch the circuitry of the device from the playback state to the recording state, as in a general device.
Further, since the drive of the record rack 66 can be easily understood from the drive operations of the racks for playback, table forwarding, and rewinding described above, a detailed explanation will be omitted. It should also be noted that the procedure for simultaneously driving the record rack 66 and the play rack 60 to bring them into a so-called recording state is also performed by the above-mentioned operation control circuit. The above-mentioned reproduction state selection, fast forwarding state selection, rewinding state selection, recording state selection, and stop state selection can be easily performed by operating a switch or the like that energizes an electromagnetic coil or the like.

As is clear from the above description, the recording medium drive control device of the present invention uses a device board made of a magnetic material as a means for configuring a power path for an electromagnetic coil, and uses the electromagnetic force generated through the device board by the action of the electromagnetic coil. By configuring the displacement means to control the drive of the recording medium by displacing the displacement means, it is possible to effectively generate electromagnetic force even if the yoke used in conventional solenoids is removed. This provides the advantageous effect of being able to provide a small and lightweight device at low cost.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the top surface of the device board of an apparatus according to an embodiment of the present invention, Fig. 2 is a plan view of the operation control mechanism arranged on the back side of the board, and Fig. 3 is a reel stand drive mechanism and triangular cam drive mechanism. 4 is a plan view of the device in the playback state, FIG. 5 is a plan view of the device in the table feed state, FIG. 6 is a plan view of the device in the rewind state, and FIG. It is a perspective view of a coil part. 10...Substrate, 12...Magnetic tape, 14...
...Supply V supply reel, 24...Cab stan, 26...
... Winding roll ~ 28 ... Pinch roller, 44 ... Switch cam, 52 ... Micro switch, 54 ... Sub board,
56...Triangular cam, 58...Cam follower, 60...Play rack, 62...Fast forward rack,
64...Rewind rack, 66...'Record rack 68, 70, 72, 74...Differential rod,
88,90,92,94"""Pinion, 96,98,
100, 102...displacement lever, 134, I36,
138, 140... Electromagnetic coil, 152..."
Leaf switch, 164... Supply reel stand, 166
...Rewinding wheel table 182...Fast forward idler,
184...Aidora returns, 216...
・Gomaidra, 224...Tape drive motor, 2
30. ...Belt, 262...Cam drive motor,
266...belt, 700...magnetic loop. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. An electromagnetic coil means, a displacement means arranged to be displaced based on the electromagnetic force generated by the electromagnetic coil means,
comprising a control means for controlling the drive of the recording medium based on the displacement operation of the displacement means, and a device substrate made of a magnetic material,
A drive control device for a recording medium, characterized in that the device substrate serves as magnetic path forming means for an electromagnetic coil together with a displacement means.