JPH0766891B2 - Rotary transformer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a rotary transformer used for a rotary magnetic head device such as a video tape recorder or a digital audio tape recorder.

SUMMARY OF THE INVENTION The present invention relates to a rotary transformer in which the coil ratios of the coil conductors of the rotor portion and the stator portion are different from each other, and the coil conductors are formed to have substantially equal facing widths by a photolithography technique. It aims to improve productivity and productivity.

[Conventional technology]

The rotary transformer is widely used, for example, in a rotary magnetic head device of a video tape recorder as a connecting means for transmitting a signal obtained by the rotary magnetic head provided on the rotary side to a circuit on the fixed side.

This rotary transformer is, for example, as shown in FIG.
The rotor portion (101) is provided on the rotating side and the stator portion (102) is provided on the stationary side, and the rotor portion and the stator portion are arranged to face each other with a minute gap. The rotor portion (101) and the stator portion (102) are each formed of a substantially disk-shaped magnetic core (103),
Winding grooves (103a), (104) provided on the opposing surface side of (104)
Concentric coil conductors (105) and (106) are wound around a). Then, for example, the rotary magnetic head connected to the rotor part (101) and the reproducing circuit connected to the stator part (102) are converted into a magnetic signal and coupled in a non-contact state (so-called electromagnetic coupling). It is configured to be.

[Problems to be solved by the invention]

By the way, the number of turns of the coil conductors (105) and (106) may be different between the rotor part (101) and the stator part (102).

That is, for example, in the rotary transformer shown in FIG. 5, the winding ratio of the coil conductors (105) and (106) is (2:
5) and the opposing widths W ₁ , W _{2 of} the coil conductors (105), (106)
Has a different structure. Therefore, a space portion remains in the winding groove (103a) on the rotor portion (101) side, and as a result, the magnetic field generated from the coil conductor wire (106) of the stator portion (102) is transmitted to the opposing coil conductor wire (105). When
So-called leakage magnetic flux increases, and good electromagnetic coupling cannot be achieved.

Therefore, it has been proposed in view of such conventional circumstances, and to provide a rotary transformer which has the same width of the coil conductor facing the rotor portion and the stator portion, shows excellent electromagnetic coupling characteristics, and is excellent in productivity. To aim.

[Means for solving problems]

In order to achieve the above-mentioned object, the rotary transformer of the present invention is a rotary transformer in which a rotor portion and a stator portion on a disk are arranged to face each other with a predetermined gap, and the rotor portion and the stator portion have opposite surfaces. Coil conductors with different numbers of turns formed by photolithography are transferred so that they are arranged in a single layer on one plane,
In addition, the coil conductors having different numbers of windings have substantially equal facing widths.

[Action]

The basic idea of the present invention is to make the opposing widths of coil conductors having different numbers of turns substantially equal to each other.

Here, for example, as shown in FIG. 6 (A) and FIG. 6 (B), the diameter of the coil conductor (105) on the rotor portion (101) side is increased, or a wire having a square cross section is used. Another possible method is to improve the wire rod so that the facing widths W ₁ and W ₂ are substantially the same as each other to eliminate the above-mentioned drawbacks.

However, as shown in FIG. 6 (A), the coil conductor (10
When the wire diameter of 5) is increased, there is a limit to the groove depth of the winding groove (103a), so the coil conductor (105) projects from the facing surface (103b) of the magnetic core (103). It is difficult to put it into practical use.

Further, as shown in FIG. 6 (B), by using a wire material having a rectangular cross section for the coil conductor (105), the opposing widths W ₁ and W ₂ can be made equal without setting the groove depth h large. However, the wire rod processing and winding work are complicated and are not practical.

In the present invention, since each coil conductor of the rotor part and the stator part is formed into a thin film structure by the photolithography technique, even if the winding ratio of each coil conductor is different, the mask pattern can be changed appropriately to easily and highly accurately It can be made equal to the conductor facing width.

〔Example〕

An embodiment of a rotary transformer to which the present invention is applied will be described below with reference to the drawings.

As shown in FIG. 1, the rotary transformer of this embodiment has a spiral coil conductor (3) on a magnetic core (2), (12) made of a non-magnetic material such as Ni-Zn ferrite or Mn-Zn ferrite. ), (13) and a rotor part (1) and a stator part (11) are arranged with a minute gap so that the coil conductors (3), (13) face each other. The holes (5) and (15) formed in the central portions of the magnetic cores (2) and (12) are engaging holes for the rotating shaft and the like.

Here, the coil conductors (3) and (13) are formed by winding grooves (4) and (14) formed in the magnetic cores (2) and (12) by cutting.
Inside, it has a thin film structure formed by using fine processing technology such as photolithography technology.
It is firmly fixed in (16).

In addition, the opposing surfaces (3a) of the coil conductors (3) and (13),
(13a) is the facing surface (2a) of the magnetic cores (2), (12),
Since it is substantially flush with (12a), the gap between the rotor part (1) and the stator part (11) can be set minutely.

Furthermore, in the present embodiment, the coil conductors (3),
The number of windings in (13) depends on the rotor (1) and stator (1
1) (2 turns on the rotor (1) side and 5 turns on the stator (11) side in this example), but the opposing widths W _R and W _S of these coil conductors (3) and (13) are substantially equal. That is, the patterning width C of the coil conductor (3)
_R is set to be larger than the patterning width C _S of the coil conductor (13). This coil shape can be easily obtained by appropriately changing the mask pattern when patterning the coil conductors (3) and (13).

Therefore, even if the number of windings of the coil conductors (3) and (13) is different between the rotor part (1) and the stator part (11), the opposing widths are equal, and the rotor part (1) and Since the gap between the stator portions (11) can be made minute, a rotary transformer having a small leakage magnetic flux and excellent electromagnetic conversion characteristics can be provided.

According to experiments by the present inventors, the rotary transformer of this embodiment (FIG. 1) is the conventional rotary transformer (FIG. 5).
It was confirmed that the electromagnetic coupling coefficient K was improved by about 3 to 10% as compared with the above. The electromagnetic coupling coefficient K is generally used as a standard for indicating the degree of electromagnetic engagement between the rotor portion and the stator portion, and is represented by the following equation (K = 1 for complete coupling).

(However, in the formula, L _R represents the inductance of the rotor unit side when the stator unit side is open, and L _S represents the inductance of the rotor unit side when the stator unit side is short-circuited.) In this embodiment, since the coil conductors (3) and (13) are formed by the photolithography technique and the opposing widths of the coil conductors are made equal to each other, it is possible to provide a rotary transformer having a small magnetic flux leakage and an excellent electromagnetic coupling characteristic.

Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment and can be applied to rotary transformers of various structures without departing from the spirit of the present invention.

For example, the present invention is also applicable to a rotary transformer corresponding to a multi-channel rotary magnetic head in which a plurality of concentric coil conductors are formed in a magnetic core, a rotary transformer in which a plurality of coil conductors are formed through insulating films, and the like. To be done.

Next, in order to make the structure of the rotary transformer of the above embodiment clearer, its manufacturing method will be described with reference to the drawings.

In order to create the stator portion that constitutes the above-mentioned rotary transformer, as shown in FIG. 2 (A), first, as shown in FIG. 2 (A), a base (21 ) Is laminated on a metal foil (22) made of a conductive metal material such as copper, and then,
A photoresist (23) made of a positive resist (for example, product name OFPR manufactured by Tokyo Ohka Co., Ltd.) corresponding to a desired coil pattern is formed on the surface of the metal foil (22). Here, the base body (1) is a dummy member for transferring the coil conductor to the magnetic core, and is a non-component of the rotary transformer.

Next, as shown in FIG. 2B, etching is performed using the photoresist (23) as a mask to form a coil conductor (24) corresponding to the pattern of the photoresist (23). In this case, the winding width (opposing width) W _S of the coil conductor (24) is the groove width S _{S of} the winding groove (25a) cut and formed in the magnetic core (25) shown in FIG. 2 (C). It is formed to be smaller than As described above, the coil conductor (24) having 5 turns is formed.

As described above, in the present embodiment, since the coil conductor (24) is formed by using the photolithography technique, the coil conductor (24) is patterned with high precision, so that the characteristic variation of the coil conductor (24). Is also advantageous in terms of downsizing and mass production of the rotary transformer.

Then, as shown in FIG. 2C, a magnetic core (2) made of a soft magnetic material such as Ni-Zn ferrite and having a winding groove (25a) corresponding to the patterning of the coil conductor (24).
5) is prepared, an adhesive (26) is formed in the groove (25a) by coating or the like, and then bonded and integrated with the base body (21). As a result, the coil conductor (24) is fixed to the magnetic core (25). The adhesive (26) is applied to the magnetic core (21).
When using a material with a relatively low electric resistance such as Mn-Zn ferrite, use an insulating adhesive.

Finally, as shown in FIG. 2 (D), the coil conductor (24) is transferred to the magnetic core (25) by dissolving and removing the base body (21) using a solvent such as methylene chloride. A stator part (20) having a different structure is obtained.

On the other hand, as shown in FIGS. 3 (A) and 3 (B), the rotor part constituting the above-mentioned rotary transformer is formed by using the same transfer technique as the above-mentioned method of forming the stator part (20). To do. In FIGS. 3A to 3D, the same members as those shown in FIGS. 2A to 2D are designated by the same reference numerals.

In forming the stator part (30), the difference from the stator part (20) is that the coil conductor (27) has a two-turn winding structure and the coil conductor facing width W _R becomes equal to the facing width W _S at the same time. That is, the photoresist (26) is patterned. That is, in the step of forming the photoresist (26) shown in FIG. 3 (A), the groove width S _R of the winding groove (25) of the magnetic core (25) [in this embodiment, the groove on the side of the stator portion (20)] The width is approximately the same as the width S _S ], and the photoresist (26) is formed so as to have the same winding width W _S of the coil conductor (24) on the stator part (20) side, and the metal foil (22) is similarly formed. Is patterned to form a coil conductor (27) shown in FIG. 3 (B).

After that, the rotor part (30) shown in FIG. 3 (D) is obtained through the same steps as the stator part (20).

Finally, the stator part (20) and the rotor part (30) created as described above are arranged at a minute interval so that the coil conductors (24) and (27) face each other, and the rotary transformer shown in FIG. Complete.

The thickness of each coil conductor (24), (27) can be controlled by appropriately changing the thickness of the metal foil (22) used.

In this way, since each coil conductor (24), (27) is formed by the photolithography technique, it is necessary to change the wire diameter as in the past or to use a complicated process such as using a square wire. Instead, it can be easily formed by appropriately changing the mask patterns of the photoresists (23) and (26).
Therefore, coil conductors (24) and (27) having different winding ratios and having the same facing width can be easily and highly accurately created. At the same time, since the obtained coil conductors (24) and (27) have uniform characteristics, good electromagnetic characteristics can be obtained. Also, the wafer (base)
Since a plurality of coil conductors can be collectively formed on the upper surface, productivity and mass productivity are significantly improved.

As described above, a rotary transformer is produced in which the winding ratios of the coil conductors of the rotor portion and the stator portion are different, and the winding ratios of the coil conductors of both are substantially equal, but this manufacturing method is limited to the above-mentioned embodiment. is not.

For example, as shown in FIGS. 4 (A) and 4 (B),
The coil conductor may be formed by a thin film forming technique. That is, first, as shown in FIG. 4A, a photoresist (42) having a desired pattern is directly formed on one plane (41a) of a conductive substrate (41) made of a conductive metal material such as Al. At the same time, a photoresist (43) is formed on the entire back surface (41b) of the base body (41). Here, the conductive substrate (4
1) is a non-component of the rotary transformer.

Next, as shown in FIG. 4 (B), using the photoresists (42) and (43) as masks, a conductive metal such as Cu is directly deposited on the base body (41) by electroplating means. Adhere to form the coil conductor (44). A vacuum thin film forming technique such as a sputtering method may be used as a means for depositing the conductive metal.

Next, after removing the photoresists (42) and (43), the coil conductor may be transferred to the magnetic core using the above-mentioned transfer technique to form the rotor part and the stator part.

Further, in the above-mentioned embodiments, the negative resist or Al was used as the substrate (1), but the material of the substrate (21) is not limited to this, and a resin such as a polyimide resin, a cyclized rubber resist or the like is also used. It is possible.

Specific examples of the polyimide-based resin include Hitachi Chemical Co., Ltd., trade name PIQ, Toray Co., trade name Semiconfine, and the like. To remove the resin, for example, a wet using a hydrazine-based etching agent is used. An etching method or a decomposition ashing method using oxygen plasma may be used.

Examples of the cyclized rubber type photoresist include OMR-83 manufactured by Tokyo Ohka Co., Ltd. As a method for removing the photoresist, a phenol type resist stripping agent or a stripping agent containing a halogenated hydrocarbon as a main component is used. The wet etching method described above, or the decomposition and removal method using oxygen plasma may be used.

〔The invention's effect〕

As is clear from the above description, in the rotary transformer of the present invention, even if the winding ratios of the coil conductors of the rotor portion and the stator portion are different, the opposing widths of both coil conductors can be easily and accurately made equal. be able to. Therefore, the leakage magnetic flux between the rotor portion and the stator portion is reduced, and good electromagnetic coupling characteristics can be obtained.

Further, since the coil conductor is formed by the photolithography technique, the productivity of the rotary transformer is improved, and the miniaturization and mass production are possible.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the rotary transformer of the present invention. FIG. 2 is a cross-sectional view of an essential part showing a method of manufacturing a stator part constituting the rotary transformer shown in FIG. 1 according to the steps, and FIG. 2 (A) shows a photoresist forming step.
FIG. 2 (B) shows a coil conductor forming process, and FIG. 2 (C).
Shows the integration step, and FIG. 2 (D) shows the substrate removal step. FIG. 3 is a cross-sectional view of an essential part showing a method of manufacturing a rotor portion constituting the rotary transformer shown in FIG. 1 according to the steps, and FIG. 3 (A) shows a photoresist forming step. ) Shows a coil conductor forming step, FIG. 3 (C) shows an integration step, and FIG. 3 (D) shows a substrate removing step. 4 (A) and 4 (B) are cross-sectional views of essential parts showing another example of the method for manufacturing a rotary transformer of the present invention. FIG. 5 is a cross-sectional view of an essential part showing a conventional rotary transformer, and FIGS. 6 (A) and 6 (B) are cross-sectional views of an essential part showing a rotor part of another example of the conventional rotary transformer. . 1 …… Rotor part 11 …… Stator part 2,12 …… Magnetic core 3,13 …… Coil conductor

Claims (1)

[Claims] 1. A rotary transformer in which a disk-shaped rotor portion and a stator portion are arranged to face each other with a predetermined gap, and a number of windings formed by photolithography is provided on the facing surfaces of the rotor portion and the stator portion. A rotary transformer, wherein different coil conductors are transferred so as to be arranged in a single layer in a plane, and the coil conductors having different numbers of windings have substantially equal facing widths.