TWI897032B - Variable resistor and method for manufacturing the same - Google Patents

Abstract

Issue: A variable resistor is provided that can suppress degradation of a comb-tooth pattern. Solution: A variable resistor 1A comprises: a substrate 11; a plurality of comb-tooth patterns 45a-45j extending with spaces between them while supporting the substrate 11; and a first resist layer 20 disposed on the substrate 11 to fill the spaces between the comb-tooth patterns 45a-45j. The comb-tooth patterns 45a-45j have an upper surface 46 on the opposite side of the substrate 11; the upper surface 46 is exposed from the first resist layer 20.

Description

Variable resistor and method for manufacturing the same

The present invention relates to a variable resistor and a method for manufacturing the variable resistor.

The variable resistor disclosed in Patent Document 1 comprises: an impedance element disposed on the upper surface of a lower film substrate; a plurality of comb-teeth patterns interconnecting the impedance element and spaced apart from each other; and a connector element disposed on the lower surface of an upper film substrate. By pressing a slider, the upper film substrate and the connector element are bent downward, bringing the connector element into contact with the comb-teeth pattern (see, for example, Patent Document 1 (paragraph [0090], Figures 8-12)). Subsequently, by pressing and sliding the upper film substrate with the slider, the comb-teeth pattern electrically connected to the connector element sequentially changes, thereby varying the resistance length (resistance value) of the impedance element (see, for example, Patent Document 1 (paragraph [0092], Figure 9)).

[Prior Technical Literature]

[Patent Literature]

[Patent Document 1] International Publication No. 2021/205899

In the aforementioned prior art, due to the space between the tooth patterns, if the slider is pressed against the upper film substrate while sliding, the connector that enters this space may contact the tooth pattern from the sides. Consequently, repeated sliding can cause the connector to repeatedly contact the tooth pattern laterally, potentially chipping the tooth pattern or causing it to fall and peel from the lower film substrate due to lateral forces. This situation poses a problem of deteriorating the tooth pattern due to repeated sliding.

The problem to be solved by the present invention is to provide a variable resistor that can suppress the degradation of the comb pattern and a method for manufacturing the variable resistor.

[1] Aspect 1 of the present invention provides a variable resistor comprising: a first substrate; a plurality of comb-tooth patterns supporting the first substrate and extending with spaces therebetween; and an insulator disposed on the first substrate so as to fill the spaces between the comb-tooth patterns; wherein the comb-tooth pattern has a front end face on the opposite side of the first substrate; and the front end face is exposed from the insulator.

[2] Aspect 2 of the present invention may be the following variable resistor: in the variable resistor of aspect 1, the insulator has a first main surface on the opposite side of the first substrate; and the height of the front end surface from the first substrate is substantially the same as the height of the first main surface from the first substrate.

[3] Aspect 3 of the present invention may be the following variable resistor: in the variable resistor of aspect 1 or aspect 2, the insulator has a first main surface opposite to the first substrate; the first main surface extends substantially parallel to the first substrate.

[4] Aspect 4 of the present invention may be the following variable resistor: In any of the variable resistors in aspects 1 to 3, the insulator includes: a first intervening portion located between the comb-tooth patterns; and a second intervening portion located between the first substrate and the comb-tooth pattern.

[5] Aspect 5 of the present invention may be the following variable resistor: in any of aspects 1 to 4, the insulator has a first principal surface opposite to the first substrate; the variable resistor includes a resistor; the plurality of comb-tooth patterns include a plurality of first comb-tooth patterns connected to the resistor; the first comb-tooth pattern includes: a first portion whose front end face is exposed from the insulator; and a second portion integrally formed with the first portion and connected to the resistor; the second portion is thinner than the first portion in a first direction perpendicular to the first principal surface.

[6] Aspect 6 of the present invention may be the following variable resistor: In any of the variable resistors in aspects 1 to 5, the variable resistor comprises: an impedance body disposed on the first substrate; a first wiring pattern disposed on the first substrate and connected to the impedance body; a spacer having an opening; a second substrate laminated on the first substrate via the spacer; a connector disposed on the second substrate within the opening and connected to the second substrate by pressing a slider from the outside of the second substrate; The first and second wiring patterns are electrically connected to the impedance body; the second wiring pattern is disposed on the second substrate and connected to the connector, or is disposed on the first substrate and electrically connected to the connector by pressing the slider; wherein, in a top view, the connector has a non-overlapping region that does not overlap with the impedance body; in a top view, the non-overlapping region includes a sliding region in which the slider can slide; the front end surface is the surface of the comb pattern facing the connector; and the resistance value between the first and second wiring patterns can be changed in response to the position of the slider.

[7] Aspect 7 of the present invention may be the following variable resistor: in the variable resistor of aspect 6, the second wiring pattern is disposed on the second substrate and connected to the connector; the plurality of comb-tooth patterns include a plurality of first comb-tooth patterns connected to the resistor; in a plan view, the first comb-tooth pattern overlaps the sliding region; and the connector contacts the first comb-tooth pattern by pressing the slider from the outer side of the second substrate.

[8] Aspect 8 of the present invention may be the following variable resistor: in the variable resistor of aspect 6, the second wiring pattern is disposed on the first substrate; the plurality of comb-tooth patterns include a plurality of first comb-tooth patterns connected to the resistor; in a plan view, the first comb-tooth pattern and the second wiring pattern overlap with the sliding area; and the connector contacts the first comb-tooth pattern and the second wiring pattern by pressing the slider from the outer side of the second substrate.

[9] Aspect 9 of the present invention may be the following variable resistor: in the variable resistor of aspect 6, the second wiring pattern is disposed on the first substrate; the plurality of comb-tooth patterns include: a plurality of first comb-tooth patterns connected to the resistor; and a plurality of second comb-tooth patterns connected to the second wiring pattern; in a plan view, the first and second comb-tooth patterns overlap with the sliding region; the first comb-tooth pattern and the second comb-tooth pattern are arranged in the sliding region along the extending direction of the connector; and the connector is brought into contact with the first and second comb-tooth patterns by pressing the slider from the first substrate.

[10] Aspect 10 of the present invention may be the following variable resistor: in any of aspects 6 to 9, the variable resistor is disposed on the first substrate and further comprises a third wiring pattern connected to the resistor; the plurality of comb-tooth patterns include a third comb-tooth pattern connected to the first wiring pattern; and a fourth comb-tooth pattern connected to the third wiring pattern; and in a plan view, the third and fourth comb-tooth patterns overlap with the sliding region.

[11] Aspect 11 of the present invention is a method for manufacturing a variable resistor, which is the method for manufacturing a variable resistor according to any one of aspects 1 to 10, and comprises: a first step of preparing a support having a release-treated surface; a second step of forming the comb-tooth pattern on the release-treated surface of the support; a third step of forming the insulator on the release-treated surface to embed the comb-tooth pattern; and a fourth step of transferring the comb-tooth pattern and the insulator from the support to the first substrate.

In the present invention, by embedding an insulator in the spaces between the comb-tooth patterns and leaving the front end of the comb-tooth pattern opposite to the first substrate exposed from the insulator, deterioration of the comb-tooth pattern can be suppressed.

1A~1C: Variable resistor

10A~10C: Bottom film substrate

11: Base Material

11a: Above

12: Above

20: First resist layer

21: Thinning area

21a: Above

22: Protrusion

22a: Above

23: First clip miscellaneous part

23a: First exposed portion

23b, 23c: First and second non-exposed portions

24: Second fold

25: Third fold

31: Wiring diagram

35: Wiring diagram

40: Impedance

45,45a~45j: Comb pattern

46: Above

47: Below

48a: Second exposed portion

48b, 48c: Third and fourth non-exposed areas

50: Second resist layer

50a: Above

51: Opening

60A, 60B: Upper side membrane substrate

61: Base material

62: Below

63: Above

70: Wiring diagram

71: Second body part

711: Parallel Department

72: Second protective layer

75,75a~75i: Comb pattern

76: Second front end face

80: Connector

80a,80b: Margin

81: First Body Section

82: First protective layer

90: spacer

91: Opening

100: Slide

110: Pressing part

200: Release film

201: Membrane

202: Exfoliation layer

NA: Non-overlapping fields

SA: Sliding Area

H ₁ ,H ₂ ,H ₃ : Height

T ₁ , T ₂ , T ₃ , T ₄ , T ₅ , T ₆ : Thickness

Figure 1 is a top view of a variable resistor according to the first embodiment of the present invention.

Figure 2 is a cross-sectional view taken along line II-II in Figure 1.

Figure 3 is a cross-sectional view taken along line III-III in Figure 1.

Figure 4 is a cross-sectional view taken along line IV-IV in Figure 1.

Figure 5 is a cross-sectional view along line V-V in Figure 1.

Figure 6 is a top view of the lower film substrate of the variable resistor according to the first embodiment of the present invention.

Figure 7 is a bottom view showing the spacer and upper film substrate of the variable resistor according to the first embodiment of the present invention.

Figures 8(A) to 8(D) are cross-sectional views illustrating an example of a method for manufacturing a variable resistor according to the first embodiment of the present invention.

Figures 9(A) to 9(D) are cross-sectional views illustrating an example of a method for manufacturing a variable resistor according to the first embodiment of the present invention.

Figure 10 is a top view of a variable resistor according to a second embodiment of the present invention.

Figure 11 is a cross-sectional view taken along line XI-XI in Figure 10.

Figure 12 is a top view of the lower film substrate of the variable resistor according to the second embodiment of the present invention.

Figure 13 is a bottom view showing the spacer and upper film substrate of the variable resistor according to the second embodiment of the present invention.

Figure 14 is a top view of a variable resistor according to a third embodiment of the present invention.

Figure 15 is a cross-sectional view taken along line XV-XV in Figure 14.

Figure 16 is a top view of the lower film substrate of the variable resistor according to the third embodiment of the present invention.

[Form used to implement the invention]

The following describes the implementation of the present invention based on the drawings.

<<First Implementation Form>>

Figure 1 is a top view of a variable resistor 1A according to the first embodiment; Figure 2 is a cross-sectional view taken along line II-II in Figure 1; Figure 3 is a cross-sectional view taken along line III-III in Figure 1; Figure 4 is a cross-sectional view taken along line IV-IV in Figure 1; and Figure 5 is a cross-sectional view taken along line V-V in Figure 1. Furthermore, Figure 6 is a top view of the lower film substrate 10A of the variable resistor 1A according to the first embodiment; and Figure 7 is a bottom view of the spacer 90 and upper film substrate 60A of the variable resistor 1A according to the first embodiment.

As shown in Figures 1 to 7 , the variable resistor 1A of this embodiment comprises a lower film substrate 10A (see Figures 2 to 6 ), an upper film substrate 60A (see Figures 2 to 5 and 7 ), a spacer 90 , and a slider 100 .

The lower film substrate 10A includes an impedance element 40, a plurality of (10 in this example) comb-tooth patterns 45a through 45j, and wiring patterns 31 and 35. In this embodiment, the plurality of comb-tooth patterns 45a through 45j may be collectively referred to as "comb-tooth pattern 45."

Meanwhile, the upper film substrate 60A includes a connector 80 electrically connected to the resistor 40 and the wiring pattern 70. These film substrates 10A and 60A are stacked with spacers 90 interposed therebetween, ensuring a gap between them. The slider 100 is configured to slide while pressing against the upper film substrate 60A within the sliding area SA (see Figure 1). The pressing action of the slider 100 electrically connects the resistor 40 and the wiring pattern 70 via the connector 80 and the comb pattern 45.

In this variable resistor 1A, the comb pattern 45 of the contact connector 80 is sequentially changed by sliding the slider 100 while pressing the upper film substrate 60A. This changes the electrical connection position between the connector 80 and the resistor 40, thereby varying the resistance length (resistance value) of the resistor 40. Examples of applications for this variable resistor 1A include variable resistance elements, position sensors, switches, and encoders. The applications of the variable resistor 1A of this embodiment are not limited to those described above.

The following is a detailed description of the structure of the variable resistor 1A of this embodiment.

As shown in Figure 6, lower film substrate 10A is a wiring board comprising the following components: base material 11, first resist layer 20, wiring patterns 31 and 35, resistor 40, comb pattern 45, and second resist layer 50. Furthermore, the substrate 11 of the present embodiment is equivalent to an example of the "first substrate" of the present invention, the first resist layer 20 of the present embodiment is equivalent to an example of the "insulator" of the present invention, the comb patterns 45a~45j of the present embodiment are equivalent to an example of the "comb pattern", the comb pattern 45a of the present embodiment is equivalent to an example of the "third comb pattern" of the present invention, the comb patterns 45b~45i of the present embodiment are equivalent to an example of the "first comb pattern", and the comb pattern 45j of the present embodiment is equivalent to an example of the "fourth comb pattern" of the present invention. Furthermore, the wiring pattern 31 of this embodiment corresponds to an example of the "first wiring pattern" of the present invention, and the wiring pattern 35 of this embodiment corresponds to an example of the "third wiring pattern" of the present invention.

Substrate 11 is a film-like member made of a flexible and electrically insulating material. Examples of materials constituting substrate 11 include resin materials, more specifically polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). More specifically, an adhesive tape having an adhesive layer can be used as substrate 11, applied to one main surface of the PET film. Alternatively, hot melt adhesive can be used in place of the adhesive layer. Furthermore, substrate 11 does not necessarily have to be flexible.

The first resist layer 20 is provided on the upper surface 12 of the substrate 11. This first resist layer 20 is formed by curing (hardening) an electrically insulating resist material. Specific examples of this resist material include resin materials such as epoxy resin, urethane resin, polyester resin, and acrylic resin.

As shown in Figures 2 and 6, the first resist layer 20 has a thinned portion 21 and a protruding portion 22. As shown in Figure 6, the thinned portion 21 surrounds the protruding portion 22 and is thinner than the protruding portion 22.

In a top view (a top view when viewing the variable resistor 1A from above or below (in the direction normal to the main surface of the variable resistor 1A (the Z direction in the figure))), the thinned portion 21 overlaps with the second resistor layer 50 and does not protrude from the second resistor layer 50. Furthermore, as shown in Figure 3, the thinned portion 21 is not directly covered by the second resistor layer 50 but has portions indirectly covered by the second resistor layer 50 via the wiring patterns 31 and 35, the resistor 40, and the comb pattern 45.

On the other hand, as shown in Figures 2 and 6 , the protrusion 22 of this embodiment is surrounded by the thinned portion 21. This protrusion 22 does not overlap with the second resist layer 50 in a top view and is exposed from the second resist layer 50. As shown in Figure 2 , the protrusion 22 is thicker than the thinned portion 21, and the upper surface 22a of the protrusion 22 protrudes upward (in the +Z direction in the figure) relative to the upper surface 21a of the thinned portion 21. Therefore, the protrusion 22 is embedded in the opening 51 of the second resist layer 50. Furthermore, the upper surface 22a of the protrusion 22 of this embodiment corresponds to an example of the "first principal surface" of the present invention.

The top surface 22a of the protrusion 22 is substantially parallel to the top surface 12 of the substrate 11. Furthermore, the height _H1 from the substrate 11 to the top surface 22a is substantially the same as the height H2 from the substrate 11 to the top surface _50a of the second resist layer 50 ( _H1 = _H2 ), making the top surfaces 22a and 50a substantially parallel.

Furthermore, as shown in Figures 2, 3, and 6, a comb-tooth pattern 45 is embedded from the thinned portion 21 of the first resist layer 20 across the protruding portion 22. Surrounding the comb-tooth pattern 45, the first resist layer 20 further includes a plurality of (nine in this example) first intercalating portions 23, a plurality of (ten in this example) second intercalating portions 24, and a plurality of (two in this example) third intercalating portions 25. As shown in Figure 2, in the first resist layer 20 of this embodiment, the plurality of first intercalating portions 23 and the plurality of second intercalating portions 24 are alternately arranged along the X-direction between the third intercalating portions 25. Furthermore, the number of the first and second clamping portions 23 and 24 is not particularly limited and can vary depending on the number of the comb tooth patterns 45.

As shown in Figure 6, the first interposing portion 23 is located between the tooth patterns 45 to fill the spaces between them. The first interposing portion 23 extends from the thinned portion 21 of the first resist layer 20 across the protruding portion 22 and along the extension direction of the tooth pattern 45 (the Y direction in the figure).

As shown in Figure 5, the first intervening portion 23 includes a first exposed portion 23a, a first non-exposed portion 23b, and a second non-exposed portion 23c. The first exposed portion 23a, the first non-exposed portion 23b, and the second non-exposed portion 23c are integrally formed.

The first exposed portion 23a constitutes a portion of the protrusion 22 and is exposed from the second resist layer 50. The upper surface 22a of the protrusion 22 of the first exposed portion 23a substantially forms a surface with the upper surface 50a of the second resist layer 50. Furthermore, the surface roughness Ra of the upper surface 22a of the protrusion 22 of the first exposed portion 23a can be, for example, 0.01 μm to 0.1 μm.

The first and second non-exposed portions 23b and 23c constitute a portion of the thinned portion 21. The first non-exposed portion 23b is located between the first exposed portion 23a and the resistor 40. The upper surface 21a of the thinned portion 21 of the first non-exposed portion 23b is covered by the second resist layer 50. Therefore, the first non-exposed portion 23b is sandwiched between the second resist layer 50 and the substrate 11.

The second non-exposed portion 23c is connected to the first non-exposed portion 23b. The upper surface 21a of the thinned portion 21 of the second non-exposed portion 23c is covered by the resistor 40. Therefore, the second non-exposed portion 23c is sandwiched between the resistor 40 and the substrate 11.

Furthermore, in this embodiment, the thickness _T1 of the first exposed portion 23a is greater than the thickness _T2 of the first non-exposed portion 23b. Meanwhile, the thickness _T2 of the first non-exposed portion 23b is greater than the thickness _T3 of the second non-exposed portion 23c ( _T1 > _T2 > _T3 ). Therefore, in the first interposed portion 23 of this embodiment, a step is formed between the first exposed portion 23a and the first non-exposed portion 23b, as well as between the first non-exposed portion 23b and the second non-exposed portion 23c. Consequently, the thickness of the first interposed portion 23 gradually decreases as it approaches the end of the comb-tooth pattern 45 on the resistor 40 side (in the -Y direction in the figure). Furthermore, the thickness of this embodiment is the thickness in the vertical direction (Z direction in the figure) relative to the upper surface 12 of the substrate 11. The Z direction of this embodiment is an example of the "first direction" of the present invention.

As shown in Figures 2 and 3, the second interposing portion 24 is located between the lower surface 47 of the tooth pattern 45 and the upper surface 12 of the substrate 11. In this embodiment, the second interposing portion 24 is located between the two first interposing portions 23, 23 and has a rectangular shape with the same width as the tooth pattern 45.

Positioning the second intervening portion 24 between the tooth pattern 45 and the substrate 11 in this manner enhances the bonding strength of the tooth pattern 45 to the substrate 11, thereby suppressing degradation of the tooth pattern 45. Furthermore, the second intervening portion 24 prevents the intrusion of water vapor and other substances from the substrate 11 side, thereby suppressing degradation of the tooth pattern 45.

As shown in Figure 2, the third interposing portion 25 is located between the second resist layer 50 and the comb patterns 45a and 45j. The third interposing portion 25 also constitutes a portion of the protrusion 22 and is exposed from the second resist layer 50. The top surface of the third interposing portion 25 is included in the top surface 22a of the protrusion 22, and thus forms a substantial surface with the top surface 50a of the second resist layer 50. Furthermore, the surface roughness Ra of the top surface 22a of the protrusion 22 of the third interposing portion 25 can be, for example, 0.01 μm to 0.1 μm.

As shown in Figure 3, wiring patterns 31 and 35 are provided on thinned portion 21 of first resist layer 20. Wiring patterns 31 and 35 are formed by curing (hardening) a conductive adhesive. The conductive adhesive is formed by mixing conductive particles, a binder resin, water or a solvent, and various additives. The conductive adhesive forming these wiring patterns 31 and 35 is a low-resistance conductive adhesive with a relatively low resistance value. The method for forming wiring patterns 31 and 35 is not particularly limited to the method described above.

Specific examples of conductive particles include silver, copper, nickel, tin, bismuth, zinc, indium, palladium, and alloys thereof. Specific examples of binder resins include acrylic resins, polyester resins, epoxy resins, vinyl resins, urethane resins, phenolic resins, polyimide resins, silicone resins, and fluororesins. Furthermore, examples of solvents included in the conductive adhesive include α-terpineol, butyl carbitol acetate, butyl carbitol, 1-decanol, butyl cellosolve, diethylene glycol monoethyl ether acetate, and tetradecane.

Although not particularly limited, in this embodiment, a silver paste containing silver as the main component of the conductive particles, or a copper paste containing copper as the main component of the conductive particles, is used as the low-resistance conductive paste. Furthermore, the conductive particles contained in the conductive paste may be metal salts. Examples of the metal salts include salts of the aforementioned metals. Furthermore, the binder resin may be omitted from the conductive paste. Furthermore, conductive ink may be used in place of the conductive paste.

As shown in Figure 6, the wiring patterns 31 and 35 of this embodiment are connected to both ends of the resistor 40. Although the wiring patterns 31 and 35 of this embodiment extend in the X direction of the figure, which is roughly parallel to the resistor 40, this is not limited to this and may also extend in directions other than the X direction, such as the Y direction.

As shown in Figures 3 and 6, the resistor 40 is located between the wiring patterns 31 and 35 and extends along the X direction in the figures. Like the wiring patterns 31 and 35, the resistor 40 is formed by curing a conductive adhesive.

The conductive paste comprising this resistor 40 is a high-resistance conductive paste having a higher resistance than the aforementioned low-resistance conductive paste. The conductive paste comprising this resistor 40 contains conductive particles having a higher resistivity than the conductive particles comprising the conductive paste comprising the wiring patterns 31 and 35. In other words, resistor 40 is made of a material having a higher resistivity than the material comprising the wiring patterns 31 and 35, and the resistance of resistor 40 is sufficiently higher than the resistance of the wiring patterns 31 and 35 to the extent that the resistance of the wiring patterns 31 and 35 is negligible. Specifically, the resistance of resistor 40 is at least 10 times the resistance of wiring patterns 31 and 35, and preferably at least 100 times the resistance of wiring patterns 31 and 35. Furthermore, the resistivity of the material constituting resistor 40 is at least 10 times the resistivity of the material constituting wiring patterns 31 and 35, and preferably at least 100 times the resistivity of the material constituting wiring patterns 31 and 35.

A specific example of such a high-resistance conductive paste is carbon paste. Specific examples of the conductive particles contained in the conductive paste constituting resistor 40 include carbon-based materials such as graphite, carbon black (furnace black, acetylene black, Ketjen black), carbon nanotubes, and carbon nanofibers.

As mentioned above, while covering the end of wiring pattern 31 on one side of the resistor 40, it also covers the end of wiring pattern 35 on the other side. Through this resistor 40, wiring patterns 31 and 35 are connected to each other. Although not specifically shown, while wiring pattern 31 on one side is connected to the power supply, wiring pattern 35 on the other side is connected to ground.

Like wiring patterns 31 and 35, comb patterns 45a-45j are formed by curing a low-resistance conductive adhesive. Specifically, each comb pattern 45a-45j is made of a material with a lower resistivity than the material forming resistor 40. The resistance of resistor 40 is sufficiently higher than that of each comb pattern 45a-45j to the extent that the resistance of each comb pattern 45a-45j is negligible. Specifically, the resistance of resistor 40 is at least 10 times, and preferably at least 100 times, the resistance of comb patterns 45a-45j. Furthermore, the resistivity of the material constituting the resistor 40 is at least 10 times, and preferably at least 100 times, the resistivity of the material constituting the comb patterns 45a to 45j.

As shown in Figure 6, the comb pattern 45a on the left side of the figure branches off from the wiring pattern 31 and protrudes in the Y direction in the figure. In other words, this comb pattern 45a is connected to the wiring pattern 31 and extends below the sliding area SA (see Figure 1). Similarly, the comb pattern 45j on the right side of the figure branches off from the wiring pattern 35 and protrudes in the Y direction in the figure. In other words, this comb pattern 45j is connected to the wiring pattern 35 and extends below the sliding area SA (see Figure 1).

In contrast, as shown in Figure 3 , the eight tooth patterns 45b through 45i located between the two end tooth patterns 45a and 45j are electrically connected to the resistor 40 by having their ends embedded in the resistor 40. Furthermore, as shown in Figure 6 , these tooth patterns 45b through 45i extend and protrude from the resistor 40 in the +Y direction. In other words, these tooth patterns 45b through 45i are connected to the resistor 40 and extend below the sliding area SA (see Figure 1 ). Furthermore, the tooth patterns 45a and 45j at the two ends can be embedded in the resistor 40 similarly to the tooth patterns 45b through 45i, rather than branching from the wiring patterns 31 and 35.

Each of the comb patterns 45a-45j extends along the Y direction in the figure, forming a linear planar shape. These multiple comb patterns 45a-45j are arranged substantially in parallel. Furthermore, these multiple comb patterns 45a-45j are arranged at substantially equal intervals. Furthermore, the number of comb patterns 45 is not particularly limited to the number described above. Incidentally, as will be described later, a greater number of comb patterns 45 increases the resolution of the output of the variable resistor 1A. Furthermore, as long as the spacing between the comb patterns 45a-45j can be ensured, the spacing between the comb patterns 45a-45j is not limited to equal intervals.

As shown in Figure 4, the comb patterns 45b-45i include a second exposed portion 48a, a third non-exposed portion 48b, and a fourth non-exposed portion 48c. The second exposed portion 48a is integrally formed with the third and fourth non-exposed portions 48b and 48c. The second exposed portion 48a of this embodiment corresponds to an example of the "first portion" of the present invention, while the fourth non-exposed portion 48c of this embodiment corresponds to an example of the "second portion" of the present invention.

The second exposed portion 48a is located between the first intervening portions 23. In this second exposed portion 48a, the upper surface 46 of the comb-tooth patterns 45b-45i is exposed from the first intervening portion 23 of the first resist layer 20. Furthermore, this upper surface 46 is not covered by the second resist layer 50. Furthermore, the upper surface 46 in this embodiment is an example of a "front end surface" in the present invention.

Furthermore, in this embodiment, the height H ₃ from the substrate 11 to the upper surface 46 is substantially the same as the heights H ₁ and H ₂ of the upper surfaces 22 a and 50 a described above ( H ₁ = H ₂ = H ₃ ). In other words, the upper surfaces 46 , 22 a , and 50 a are substantially one surface. Furthermore, the surface roughness Ra of the upper surface 46 of the comb-tooth patterns 45 b - 45 i of the second exposed portion 48 a can be, for example, 0.01 μm to 0.1 μm.

Furthermore, in this embodiment, the upper surface 46 is substantially parallel to the upper surface 12 of the substrate 11. Therefore, the upper surface 46 is also substantially parallel to the upper surface 22a and the upper surface 50a.

The third non-exposed portion 48b is located between the second exposed portion 48a and the resistor 40. The upper surface 46 of the third non-exposed portion 48b is covered by the second resist layer 50. Therefore, the third non-exposed portion 48b is sandwiched between the second resist layer 50 and the second intervening portion 24 of the first resist layer 20.

The fourth non-exposed portion 48c is located between the third non-exposed portion 48b and the resistor 40. The upper surface 46 of the fourth non-exposed portion 48c is covered by the resistor 40. Therefore, the fourth non-exposed portion 48c is sandwiched between the resistor 40 and the second sandwiching portion 24 of the first resist layer 20.

Furthermore, in this embodiment, the thickness _T4 of the second exposed portion 48a is greater than the thickness _T5 of the third non-exposed portion 48b, while the thickness T5 of the third non-exposed portion 48b is also greater than the thickness _T6 of the fourth non-exposed portion 48c ( _T4 > _T5 > _T6 ). Therefore, in the comb-tooth patterns 45b-45i of this embodiment, a step is formed between the second exposed portion 48a and the third non-exposed portion 48b, as well as between the third non-exposed portion 48b and the fourth non-exposed portion 48c. Consequently, the thickness of the comb-tooth patterns 45b-45i gradually decreases in thickness as viewed in the -Y direction in the figure.

Meanwhile, the cross-sectional shapes of tooth patterns 45a and 45j, located at the left and right ends of tooth pattern 45, differ slightly from those of tooth patterns 45b through 45i. Although not specifically illustrated, because the resistor 40 is sandwiched between tooth patterns 45a and 45j and the second resist layer 50, the tooth patterns 45a and 45j lack fourth non-exposed portions 48c. Instead, third non-exposed portions 48b extend from the second exposed portions 48a to the wiring patterns 31 and 35.

The second resist layer 50, like the first resist layer 20, is formed by curing (hardening) a resist material. Examples of this resist material include epoxy resins, urethane resins, polyester resins, and acrylic resins.

As shown in Figures 2-4 , the second resist layer 50 covers the thinned portion 21 of the first resist layer 20, the wiring patterns 31 and 35, the resistor 40, and the third non-exposed portion 48b of the comb pattern 45. The second resist layer 50 has an opening 51 and surrounds the protruding portion 22 of the first resist layer 20.

As shown in Figure 7, the upper film substrate 60A is a wiring board comprising a base material 61, a wiring pattern 70, and a connector 80. The base material 61 of this embodiment corresponds to an example of the "second base material" of the present invention, and the wiring pattern 70 of this embodiment corresponds to an example of the "second wiring pattern" of the present invention.

Substrate 61, like substrate 11, is a film-like member made of a flexible and electrically insulating material. Examples of materials constituting substrate 11 include resins, and more specifically, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). Furthermore, the materials constituting substrate 61 are not limited to those listed above. Substrate 61 may also be made of a plate material made of a conductive material such as metal. In this case, substrate 61 can also function as connector 80. Furthermore, substrate 61 can also function as wiring pattern 70. Furthermore, even when substrate 61 is made of a conductive plate material, connector 80 and wiring pattern 70 may be formed on substrate 61 separately from the substrate.

Wiring pattern 70 is formed by printing a low-resistance conductive paste onto lower surface 62 of substrate 61 and curing it. Specifically, wiring pattern 70 is made of a material having a lower resistivity than the material constituting resistor 40. The resistance of resistor 40 is sufficiently higher than that of wiring pattern 70 to the extent that the resistance of wiring pattern 70 is negligible. Specifically, the resistance of resistor 40 is at least 10 times, and preferably at least 100 times, the resistance of wiring pattern 70. Furthermore, the resistivity of the material constituting resistor 40 is at least 10 times, and preferably at least 100 times, the resistivity of the material constituting wiring pattern 70. Furthermore, the method for forming the wiring pattern is not limited to the above.

The connector 80 is directly connected to the wiring pattern 70. The connector 80 includes a first body portion 81 and a first protective layer 82. Furthermore, the connector 80 may not include the first protective layer 82.

The first body 81 is provided on the lower surface 62 of the substrate 61. Similar to the wiring patterns 31 and 35 described above, this first body 81 is formed by printing and curing a low-resistance conductive paste. Specifically, the first body 81 is made of a material having a lower resistivity than the material constituting the resistor 40. The resistance of the resistor 40 is sufficiently higher than that of the first body 81 to the extent that the resistance of the first body 81 is negligible. Specifically, the resistance of the resistor 40 is at least 10 times, and preferably at least 100 times, the resistance of the first body 81. Furthermore, the resistivity of the material constituting the resistor 40 is at least 10 times, and preferably at least 100 times, the resistivity of the material constituting the first body 81.

On the other hand, the first protective layer 82 protects the first main body 81 and is formed by printing and curing a high-resistance conductive adhesive. This first protective layer 82 is provided on the lower surface 62 of the substrate 61 to cover the entire first main body 81.

As shown in FIG1 , this connector 80 is provided on the lower surface 62 of the substrate 61 so as to partially overlap with the comb pattern 45 of the lower film substrate 10A in a plan view.

Like the aforementioned substrates 11 and 61, spacer 90 is a film-like member made of a flexible and electrically insulating material. Examples of materials for spacer 90 include resins, and more specifically, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN).

As shown in Figures 1 to 5 and 7, the spacer 90 has a rectangular opening 91. This opening 91 is larger than the connector 80 and is large enough to contain it. In this embodiment, the opening 91 is not limited to a size sufficient to contain not only the connector 80 but also the tooth pattern 45. When the film substrates 10A and 60A are laminated with the spacer 90 interposed therebetween, the opening 91 is formed in the spacer 90 to contain both the connector 80 and the tooth pattern 45. Furthermore, at least a portion of the connector 80 is sufficient within the opening 91 of the spacer 90; a portion of the connector 80 may extend outside the opening 91 and become sandwiched between the spacer 90 and the substrate 61.

As described above, the film substrates 10A and 60A are laminated with spacers 90 interposed therebetween. As shown in Figures 2 to 5 , the film substrates 10A and 60A are laminated so that the lower surface 62 of the base 61 of the upper film substrate 60A faces the upper surface 12 of the base 11 of the lower film substrate 10A. Furthermore, while the base 11 of the lower film substrate 10A and the spacers 90 are bonded together via a bonding layer (not shown), the spacers 90 and the base 61 of the upper film substrate 60A are also bonded together via a bonding layer (not shown).

Next, as shown in Figure 1, in a top view, the connector 80 and the comb pattern 45 are contained within the opening 91. Furthermore, as shown in Figure 4, in a cross-sectional view, the connector 80 and the comb pattern 45 face each other. In this embodiment, as shown in Figure 1, in a top view, the connector 80 has a non-overlapping area NA that does not overlap with the resistor 40.

As shown in Figures 2, 4, and 5, spacers 90 ensure a gap between connector 80 and comb-tooth pattern 45. As will be described later, pressing slider 100 deforms base 11 of upper film substrate 60A, and this deformation brings connector 80 into contact with comb-tooth pattern 45, creating an electrical connection.

Furthermore, in this embodiment, the thickness of the spacer 90 is set so that the connector 80 and the comb pattern 45 do not contact each other when not pressed, but this is not particularly limited to this. The thickness of the spacer 90 can also be set so that the connector 80 and the comb pattern 45 are in normal contact.

Furthermore, the "electrical connection" between the connector and the resistor in the present invention refers to a state in which the resistance between the connector and the comb pattern is below a predetermined threshold. Therefore, it does not include the state described above where the connector and the comb pattern are simply in contact when not pressed.

The slider 100 has a semi-cylindrical pressing portion 110 at its tip and is made of, for example, a metal material. The structure of the slider 100 is not limited to the above, as long as it can slide while pressing the upper surface 63 of the base 61 of the upper film substrate 60A. Furthermore, in this embodiment, since the slider 100 presses the upper surface 63 of the base 61 of the upper film substrate 60A, the slider 100 may be made of an electrically insulating material such as a resin. Furthermore, as described later, the operator's finger may be used in place of the slider 100.

This slider 100 is kept movable in a frame (not shown) that houses the variable resistor 1A. Then, by applying a predetermined pressure to the pressing portion 110, the upper surface 63 of the base material 61 of the upper film substrate 60A is pressed, and the slider 100 can move back and forth along the X direction in the figure (the extension direction (long side direction) of the connector 80) while maintaining this pressure to a certain extent. In this embodiment, as shown in FIG1 , the sliding area SA in which this slider 100 can slide is included in the non-overlapping area NA of the connector 80 in a top view and does not overlap with the resistor 40. Then, the entire area of the connector 80 becomes the non-overlapping area NA. The slider 100 can move back and forth along the X direction in the figure in this sliding area SA. The sliding area SA of this embodiment is equivalent to an example of the "sliding area" of the present invention.

As shown in Figure 2, pressing slider 100 causes base 61 of upper film substrate 60A to bend downward, bringing comb-tooth pattern 45 into contact with connector 80. Consequently, connector 80 electrically connects resistor 40 to wiring pattern 70. Specifically, in the state shown in Figure 2, comb-tooth pattern 45f among comb-tooth patterns 45a-45j is electrically connected to connector 80.

Furthermore, by pressing the slider 100, the number of comb patterns 45a-45j connected to the connecting body 80 at the same time can also be multiple.

Next, in this embodiment, by sliding the slider 100 while pressing the upper film substrate 60A, the comb pattern 45 connected by the connector 80 changes sequentially, thereby making the resistance length (resistance value) of the resistor 40 variable.

For example, in the state shown in Figure 2 , as described above, tooth pattern 45f is connected via connector 80 . From this state, as slider 100 slides in the +X direction in the figure, the tooth pattern 45 connected via connector 80 changes: tooth pattern 45f → tooth pattern 45g → tooth pattern 45h → tooth pattern 45i → tooth pattern 45j.

In response to this, the wiring pattern 70 connected to the connector 80 detects the voltage (detection voltage) corresponding to the comb pattern 45 connected via the connector 80. In other words, the resistance between the wiring patterns 31 and 70 changes depending on the pressed position of the slider 100. As the slider 100 slides in the +X direction in the figure, the resistance between the wiring patterns 31 and 70 gradually increases as the slider 100 slides. Connecting the wiring patterns 31 and 70 of this variable resistor 1A to a multimeter or other device will output the potential difference between the power supply voltage and the detection voltage of the wiring pattern 70.

On the other hand, as shown in Figure 2, when slider 100 slides in the -X direction, the combination of comb patterns connected by connector 80 changes as slider 100 slides: comb pattern 45f → comb pattern 45e → comb pattern 45d → comb pattern 45c → comb pattern 45b → comb pattern 45a. In this case, the resistance between wiring patterns 31 and 70 gradually decreases as slider 100 slides.

For example, when the comb pattern 45a on the left end of Figure 2 is electrically connected to the wiring pattern 70 via the connector 80, the wiring pattern 70 will detect a voltage that is substantially equal to the power supply voltage. A multimeter or the like will output the potential difference between the power supply voltage and the voltage detected by the wiring pattern 70 (e.g., 0 [V]).

In contrast, when the comb pattern 45f in the middle is electrically connected to the wiring pattern 70 via the connector 80, the wiring pattern 70 will detect a voltage approximately half the power supply voltage, and a multimeter or the like will output the potential difference between the power supply voltage and the voltage detected by the wiring pattern 70 (e.g., 2.5V).

Furthermore, when the comb pattern 45j on the right end of Figure 2 is electrically connected to the wiring pattern 70 via connector 80, the wiring pattern 70 will detect a voltage that is approximately the same as the ground potential. A multimeter or the like will output the potential difference between the power supply voltage and the voltage detected by the wiring pattern 70 (e.g., 5 [V]).

In this manner, in this embodiment, the resistance between wiring patterns 31 and 70 changes according to the comb pattern 45 connected by connector 80, resulting in a step-like output from variable resistor 1A. Consequently, increasing the number of comb patterns 45 results in a narrower pitch, thereby improving the resolution of the output from variable resistor 1A.

As described above, in this embodiment, the first intervening portion 23 of the first resist layer 20 is embedded in the spaces between the tooth patterns 45a-45j, thereby reducing contact with the side surfaces of the tooth patterns 45a-45j of the connector 80. This prevents the tooth patterns 45a-45j from being worn away, or from being toppled and separated from the underlying film substrate by lateral forces, thereby suppressing degradation of the tooth patterns 45a-45j.

Furthermore, since the comb patterns 45a and 45j located at the left and right ends of the comb pattern 45 are protected by the first and third clamping portions 23 and 25, degradation of the comb patterns 45a and 45j can be suppressed.

Furthermore, in the aforementioned prior art, there are differences in the amount of deflection of the upper film substrate and connector when the connector contacts the top surface of the comb pattern, and when the connector enters the space between the comb patterns. Consequently, the slider can move vertically regardless of the sliding direction, potentially causing unstable electrical contact between the connector and the comb pattern. This degrades the detection accuracy of the variable resistor (for example, the linear accuracy of the variable resistor's output value relative to the slider's position).

In contrast, in this embodiment, when the slider 100 moves to a position corresponding to the space between the tooth patterns 45, movement of the connector 80 downward (in the -Z direction in the figure) within the space between the tooth patterns 45 is reduced by the first and third clamping portions 23 and 25. This suppresses downward movement of the slider 100, thereby minimizing degradation in the detection accuracy of the variable resistor.

Furthermore, in this embodiment, since the height _H3 of the upper surface 46 of the comb pattern 45 is substantially the same as the height _H2 of the upper surfaces 22a of the first and third sandwiching portions 23 and 25, the slider 100 can be made almost unable to slide in the vertical direction, thereby suppressing the deterioration of the detection accuracy of the variable resistor.

Furthermore, in this embodiment, because the upper surface 46 of the comb pattern 45 is substantially parallel to the upper surfaces 22a of the first and third sandwiching portions 23 and 25, the slider 100 is virtually unable to move vertically and slide, thereby suppressing degradation of the variable resistor's detection accuracy.

Next, the manufacturing method of the variable resistor 1A according to the first embodiment will be described with reference to the figures. Figures 8(A) to 9(D) are cross-sectional views illustrating an example of the manufacturing method of the variable resistor 1A according to the first embodiment. The upper figures of Figures 8(A) to 8(D) correspond to the cross-sectional views taken along line II-II in Figure 1, and the lower figures of Figures 8(A) to 8(D) correspond to the cross-sectional views taken along line III-III in Figure 1. Similarly, the upper figures of Figures 9(A) to 9(D) correspond to the cross-sectional views taken along line II-II in Figure 1, and the lower figures of Figures 9(A) to 9(D) correspond to the cross-sectional views taken along line III-III in Figure 1.

First, as shown in Figure 8(A), a release film 200 is prepared. The release film 200 of this embodiment comprises a film 201 and a release layer 202 disposed on one main surface of the film 201. The film 201 is made of a resin material. Examples of this resin material include PET. The release layer 202 is formed by applying a release agent to the film 201. Examples of this release agent include silicone-based release agents and fluorine-based release agents. The release film 200 of this embodiment serves as an example of the "support" of the present invention, and the release layer 202 of this embodiment serves as an example of the "release treatment surface" of the present invention.

By printing a resist material onto the release layer 202 of the release film 200 and curing (hardening) the material, a second resist layer 50 is formed. At this point, as shown in the upper image of FIG8(A), the area where the opening 51 is to be formed is not coated with the resist material. Thus, a second resist layer 50 having the opening 51 is formed.

Furthermore, the resist material can be printed using either contact coating or non-contact coating. Specific examples of contact coating include screen printing, gravure printing, lithographic printing, gravure offset printing, and elastic printing. On the other hand, specific examples of non-contact coating include inkjet printing, spray coating, dispense coating, and jet dispense coating. The heat source for curing the resist material is not particularly limited, but examples thereof include electric furnaces, infrared furnaces, far infrared (IR) furnaces, near infrared (NIR) furnaces, and laser irradiation devices. Heat treatment may also be performed using a combination of these.

Next, as shown in the lower diagram of Figure 8(B), a high-resistance conductive paste is printed on the second resist layer 50 and cured (hardened) to form the resistor 40. The high-resistance conductive paste described above can be used. While not particularly limited, the printing and curing methods for the high-resistance conductive paste are similar to those used for the second resist layer 50 described above.

Next, as shown in Figure 8(C), a low-resistance conductive paste is printed from inside opening 51 across resistor 40 and cured (hardened) to form a comb pattern 45. The low-resistance conductive paste described above can be used. While not particularly limited, the printing and curing methods for the low-resistance conductive paste are similar to those used for the second resist layer 50 described above.

Next, as shown in Figure 8(D), a low-resistance conductive paste is printed on both ends of resistor 40 to form wiring patterns 31 and 35. The low-resistance conductive paste described above can be used. While not particularly limited, the printing and curing methods for the low-resistance conductive paste are similar to those used for the second resist layer 50 described above.

Furthermore, the order of forming the comb pattern 45 in FIG8(C) and the order of forming the wiring patterns 31 and 35 in FIG8(D) may be reversed. Alternatively, both steps may be performed in the same step.

Next, as shown in Figure 9(A), a resist material is printed on release film 200 and cured (hardened) to form first resist layer 20, covering wiring patterns 31 and 35, resistor 40, comb pattern 45, and second resist layer 50. The resist material can be the same as that used to form second resist layer 50. The printing and curing methods for the resist material are not particularly limited, but can be the same as those used to form second resist layer 50.

At this point, the resist material is filled into the spaces between the tooth patterns 45 and between the second resist layer 50 and the tooth pattern 45 and then cured. This forms the first intervening portion 23 embedded in the spaces between the tooth patterns 45 and the third intervening portion 25 embedded in the spaces between the second resist layer 50 and the tooth pattern 45. Furthermore, the resist material is printed to cover the tooth pattern 45 and cured, forming the second intervening portion 24.

Next, as shown in Figure 9(B), substrate 11 is attached to first resist layer 20. As described above, substrate 11 can be made of, for example, an adhesive tape having an adhesive layer (not shown), and substrate 11 is attached to first resist layer 20 via this adhesive layer.

Next, as shown in Figure 9(C), the release film 200 is peeled off. This completes the lower film substrate 10A described above. Specifically, the method for manufacturing the variable resistor 1A of this embodiment forms the first and second resistor layers 20, 50, wiring patterns 31, 35, resistor 40, and comb pattern 45 on the release film 200, then transfers them to the substrate 11 to produce the lower film substrate 10A.

When the lower film substrate 10A is manufactured in this manner, the comb pattern 45 and the first resist layer 20 are directly formed on the release film 200 and then transferred. This allows the upper surface 46 of the comb pattern 45 to be easily exposed through the protrusion 22 of the first resist layer 20, which embeds the comb pattern 45. For example, if the first resist layer is formed after forming the comb pattern on the substrate, there is a high probability that the resist material will inadvertently adhere to the upper surface of the comb pattern, making it difficult to expose the upper surface of the comb pattern.

Furthermore, the upper surface 46 of the tooth pattern 45, the upper surface 22a of the protrusion 22 of the first resist layer 20 in which the tooth pattern 45 is embedded, and the upper surface 50a of the second resist layer 50 are formed on the same main surface of the release film 200. This allows the upper surfaces 46, 22a, and 50a to be easily formed on the same surface.

Furthermore, since the surface shape of the highly smooth release film 200 can be transferred to the upper surfaces 46, 22a, and 50a, the upper surfaces 46, 22a, and 50a can be formed smoothly. For example, the surface roughness Ra of the upper surfaces 46, 22a, and 50a can be made between 0.01 μm and 0.1 μm.

Next, as shown in FIG9(D), the upper film substrate 60A is attached to the lower film substrate 10A via spacers 90. Furthermore, the wiring pattern 70 and connectors 80 of the lower film substrate 10A are formed by printing on the lower surface 62 of the substrate 61 as described above. As described above, the variable resistor 1A is manufactured.

Furthermore, although this embodiment forms the first resist layer 20, wiring patterns 31, 35, resistor 40, comb pattern 45, and second resist layer 50 of the lower film substrate 10A on the release film 200 and then transfers them, this is not limiting. Alternatively, the first resist layer 20 and comb pattern 45 may be formed on the release film 200 and then transferred to the substrate 11, followed by forming the wiring patterns 31, 35, resistor 40, and second resist layer 50 on the substrate 11.

<<Second Implementation Form>>

Figure 10 is a top view of a variable resistor 1B according to the second embodiment, and Figure 11 is a cross-sectional view taken along line XI-XI in Figure 10 . Figure 12 is a top view of the lower film substrate 10B of the variable resistor 1B according to the second embodiment. Figure 13 is a bottom view of the spacer 90 and upper film substrate 60B of the variable resistor 1B according to the second embodiment.

As shown in Figures 10 to 13 , the variable resistor 1B of this embodiment differs from the variable resistor 1A of the first embodiment in that the wiring pattern 70 is formed on the lower film substrate 10B rather than the upper film substrate 60B. However, the remaining configuration is the same as that of the first embodiment. The following description will focus solely on the differences between the variable resistor 1B of the second embodiment and the first embodiment. Components identical to those of the first embodiment are designated by the same reference numerals, and their description will be omitted.

As shown in FIG11 , the wiring pattern 70 of this embodiment is formed on the substrate 11 via the first resist layer 20 . This wiring pattern 70 includes a second main portion 71 and a second protective layer 72 .

The second main portion 71, similar to the wiring patterns 31 and 35 described above, is formed by printing and curing a low-resistance conductive adhesive. More specifically, in the step shown in Figure 8(C), the second main portion 71 can be formed by printing and curing a low-resistance conductive adhesive on the second protective layer 72 formed inside the opening 51 of the second resist layer 50.

The second body 71 is made of a material having a lower resistivity than the material forming the resistor 40. The resistance of the resistor 40 is sufficiently higher than that of the second body 71 to the extent that the resistance of the second body 71 is negligible. Specifically, the resistance of the resistor 40 is at least 10 times, and preferably at least 100 times, the resistance of the second body 71. Furthermore, the resistivity of the material forming the resistor 40 is at least 10 times, and preferably at least 100 times, the resistivity of the material forming the second body 71.

As shown in Figure 12, the second body portion 71 extends along the X direction in the figure. The end of the second body portion 71 has a parallel portion 711 extending substantially parallel to the resistor 40. The planar shape of the second body portion 71 is not particularly limited to that described above.

The second protective layer 72 of the wiring pattern 70 covers the parallel portion 711 of the second main body 71. This second protective layer 72 protects the parallel portion 711 of the second main body 71 and is formed by printing and curing a high-resistance conductive glue having a higher resistance than the low-resistance conductive glue described above. For example, this second protective layer 72 can be formed by printing and curing a high-resistance conductive glue inside the opening 51 of the second resist layer 50 in the step shown in FIG8(B).

As a specific example of such a high-resistance conductive paste, carbon glue can be exemplified, though not particularly limited. The second protective layer 72 has a length approximately equal to the length of the resistor 40 along the X direction in the figure, and the resistor 40 and the comb pattern 45 are arranged with a predetermined spacing. In other words, the second protective layer 72 of the wiring pattern 70 is arranged substantially parallel to the resistor 40 and also substantially parallel to the arrangement direction of the comb pattern 45. Furthermore, the wiring pattern 70 does not necessarily need to have the second protective layer 72.

On the other hand, as shown in Figures 10, 11, and 13, the connector 80 of this embodiment is not connected to the wiring pattern 70 as in the first embodiment. In this embodiment, the connector 80 has a wider rectangular planar shape than the connector 80 of the first embodiment. Furthermore, in a top view, the connector 80 is positioned on the lower surface 62 of the substrate 61 so that the edge 80a on one side of the connector 80 (the edge on the -Y side along the X direction in the figure) overlaps with the comb pattern 45, while the edge 80b on the other side of the connector 80 (the edge on the +Y side along the X direction in the figure) overlaps with the wiring pattern 70.

As shown in Figure 11, the variable resistor 1B of this embodiment is bent beneath the base 61 of the upper film substrate 60B by pressing the slider 100. The connector 80 and the comb pattern 45 each contact the wiring pattern 70, electrically connecting the connector 80 to the resistor 40 and the wiring pattern 70. Subsequently, by sliding the slider 100 in the X direction while pressing the upper film substrate 60B, the connection position between the connector 80 and the resistor 40 is changed, thereby making the resistor 40's resistance length (resistance value) variable.

Specifically, as described above, a power supply voltage (e.g., 5V) is applied to the wiring pattern 31 on one side connected to the resistor 40, while the wiring pattern 35 on the other side connected to the resistor 40 is grounded. Furthermore, when the slider 100 is pressed, the wiring pattern 70 is electrically connected to the resistor 40 via the connector 80. This wiring pattern 70 is electrically connected to the resistor 40 at any position in the X direction in the figure. Therefore, the wiring pattern 70 detects a voltage (detection voltage) depending on the position of the slider 100. In other words, in this embodiment, the resistance between the wiring patterns 31 and 70 varies depending on the position of the slider 100. Next, a multimeter (not shown) or the like is connected to the wiring patterns 31 and 70 of the variable resistor 1B, and outputs the potential difference between the power supply voltage and the detection voltage of the wiring pattern 70.

For example, when the slider 100 within the sliding area SA is located at the left end in Figure 10 , since the connection position of the connector 80 of the resistor 40 is also at the left end, the wiring pattern 70 will detect a voltage that is almost the same as the power supply voltage. The multimeter will output the potential difference between the power supply voltage and the voltage detected by the wiring pattern 70 (e.g., 0 [V]).

In contrast, as shown in Figure 10 , when the slider 100 is located approximately in the center of the sliding area SA, the connection position of the connector 80 of the resistor 40 is also approximately in the center. Therefore, the wiring pattern 70 detects a voltage approximately half the power supply voltage. A multimeter or the like outputs the potential difference between the power supply voltage and the voltage detected by the wiring pattern 70 (e.g., 2.5 V).

Furthermore, when the slider 100 is located at the right end of the diagram within the sliding area SA, since the connection position of the connector 80 of the resistor 40 is also at the right end, the wiring pattern 70 will detect a voltage that is almost the same as the ground. A multimeter or the like will output the potential difference between the power supply voltage and the voltage detected by the wiring pattern 70 (e.g., 5 V).

In this second embodiment, the first intervening portion 23 is embedded in the space between the comb-tooth patterns 45. Similar to the first embodiment, this can suppress degradation of the comb-tooth pattern 45 while also reducing the deterioration of the detection accuracy of the variable resistor 1B.

<<Third Implementation Form>>

Figure 14 is a top view of a variable resistor 1C according to the third embodiment, and Figure 15 is a cross-sectional view taken along line XV-XV in Figure 14 . Figure 16 is a top view of the lower film substrate 10C of the variable resistor 1C according to the third embodiment.

The variable resistor 1C of this embodiment, as shown in Figures 14 to 16, has the following differences compared to the variable resistor 1B of the second embodiment: (1) the lower film substrate 10C has comb patterns 75a to 75i and (2) the connector 80 does not overlap with the wiring pattern 70. Other than this, the structure is the same as the second embodiment. The following will only describe the differences between the variable resistor 1C of the third embodiment and the second embodiment, and the same symbols are added to the same structure as the second embodiment and omitted. Furthermore, in this embodiment, a plurality of comb patterns 75a to 75i are sometimes collectively referred to as the comb pattern 75.

Comb pattern 75, like comb pattern 45, is formed by printing and curing a low-resistance conductive paste. As shown in Figure 14, comb pattern 75 of this embodiment is positioned between resistor 40 and wiring pattern 70. Furthermore, comb pattern 75 of this embodiment is an example of the "second comb pattern" of the present invention.

As shown in Figure 16 , each of the comb-tooth patterns 75a-75i has a linear planar shape, diverging from the second main portion 71 of the wiring pattern 70 and extending in the Y direction in the figure. Furthermore, the comb-tooth patterns 75a-75i protrude from the wiring pattern 70 toward the resistor 40. In other words, the comb-tooth patterns 75a-75i, while connected to the wiring pattern 70, extend below the sliding area SA. Furthermore, these multiple comb-tooth patterns 75a-75i are arranged in parallel at substantially equal intervals.

As shown in Figure 14 , all tooth patterns 45a-45j and 75a-75i face the connector 80 via the opening 91 of the spacer 90 and overlap with the sliding area SA of the slider 100 in a plan view. Furthermore, as shown in Figures 14-16 , the tooth patterns 45a-45j and the tooth patterns 75a-75i are arranged along the X direction in the figures in a plan view and are substantially evenly spaced.

Furthermore, the number of comb patterns 45 and 75 is not particularly limited to that described above. Furthermore, the arrangement of the comb patterns 45 and 75 is also not particularly limited to that described above. Incidentally, as will be described later, a greater number of comb patterns 45 and 75 can improve the resolution of the output of the variable resistor 1C. Furthermore, as long as the spacing between the comb patterns 45 and 75 can be ensured, the spacing between the comb patterns 45 and 75 is not limited to equal spacing.

The first intervening portion 23 of the first resist layer 20 of this embodiment includes a portion embedded in the spaces between the tooth patterns 45, a portion embedded in the spaces between the tooth patterns 75, and a portion embedded in the spaces between the tooth patterns 45 and 75. These portions are interconnected. Therefore, the planar shape of the first intervening portion 23 is a serpentine shape extending in the X-direction.

Furthermore, the third interposing portion 25 is embedded in the space between the second resist layer 50 and the tooth patterns 45a and 45j, and further embedded in the space between the second resist layer 50 and the tooth patterns 75a and 75i. Therefore, the planar shape of the third interposing portion 25 is L-shaped.

As shown in Figures 14 and 15 , the pressing action of slider 100 causes base 61 of upper film substrate 60B to bend downward, allowing connectors 80 to contact adjacent tooth patterns 45 and 75. Consequently, connectors 80 electrically connect resistor 40 and wiring pattern 70. Specifically, in the state shown in Figure 15 , tooth pattern 45f among tooth patterns 45a-45j and tooth pattern 75e among tooth patterns 75a-75i are electrically connected via connector 80.

Furthermore, by pressing the slider 100, the connector 80 can simultaneously connect to multiple comb patterns 45a-45j. Similarly, by pressing the slider 100, the connector 80 can simultaneously connect to multiple comb patterns 75a-75i.

Next, in this embodiment, by pressing and sliding the upper film substrate 60B with the slider 100, the combination of the comb patterns 45 and 75 connected by the connector 80 is sequentially changed, thereby making the resistance length (resistance value) of the resistor 40 variable.

For example, in the state shown in Figure 15 , as described above, comb patterns 75e and 45f are connected by connector 80. From this state, as slider 100 slides in the +X direction in the figure, the combination of comb patterns connected by connector 80 changes to: comb patterns 75e, 45f → comb patterns 45f, 75f → comb patterns 75f, 45g → comb patterns 45g, 75g → comb patterns 75g, 45h → ‧‧‧ → comb patterns 45i, 75i → comb patterns 75i, 45j.

In conjunction with this, wiring pattern 70, which connects comb patterns 75a-75i, detects a voltage (detection voltage) corresponding to the combination of comb patterns 45 and 75 connected via connector 80. In other words, this embodiment also changes the resistance between wiring patterns 31 and 70 in response to the pressed position of slider 100. When slider 100 slides in the +X direction in the figure, the resistance between wiring patterns 31 and 70 gradually increases as slider 100 slides. If wiring patterns 31 and 70 of this variable resistor 1C are connected to a multimeter, the multimeter outputs the potential difference between the power supply voltage and the detection voltage of wiring pattern 70.

On the other hand, when slider 100 is slid in the -X direction in the figure from the state shown in Figure 15, as slider 100 slides, the combination of comb patterns connected by connector 80 changes as slider 100 slides: comb pattern 45f, 75e → comb pattern 75e, 45e → comb pattern 45e, 75d → comb pattern 75d, 45d → comb pattern 45d, 75c → ‧‧‧ → comb pattern 45b, 75a → comb pattern 75a, 45a. In this case, the resistance between wiring patterns 31 and 70 gradually decreases as slider 100 slides.

In this third embodiment, since the first intervening portion 23 is also embedded in the space between the comb-tooth patterns 45 and 75, similar to the first embodiment, degradation of the comb-tooth patterns 45 and 75 can be suppressed while also reducing the deterioration of the detection accuracy of the variable resistor 1C.

Furthermore, the embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit the present invention to the embodiments described above. Therefore, the elements disclosed in the embodiments described above are intended to encompass all design modifications, equivalents, and the like within the technical field to which the present invention pertains.

For example, in the first to third embodiments, the comb pattern 45 is formed on the lower film substrate 10A, but it can also be formed on the upper film substrate 60A pressed by the slider 100.

Furthermore, in the first through third embodiments, the variable resistors 1A-1C are operated using the slider 100 provided within the variable resistors 1A-1C. However, this is not a limitation. For example, the variable resistors may be operated using the operator's finger in place of the slider 100.

Furthermore, in the above embodiment, while wiring pattern 31 is connected to the power supply and wiring pattern 35 is also grounded, and the resistance values of variable resistors 1A-1C are detected by obtaining a detection voltage from wiring pattern 70, the circuit configuration for detecting the resistance values of the variable resistors is not particularly limited to this.

For example, wiring pattern 35 may not be provided, and the power supply may be connected to wiring patterns 31 and 70. In this case, the resistance value between wiring patterns 31 and 70 can also be changed according to the pressed position of slider 100.

1A: Variable resistor 10A: Lower film substrate 11: Substrate 12: Top surface 20: First resist layer 21: Thinned portion 21a: Top surface 22: Protrusion 22a: Top surface 23: First interlayer 24: Second interlayer 25: Third interlayer 45a-45j: Comb pattern 46: Top surface 47: Bottom surface 50: Second resist layer 50a: Top surface 51: Opening 60A: Upper film substrate 61: Substrate 62: Bottom surface 63: Top surface 80: Connector 81: First body 82: First protective layer 90: Spacer 91: Opening 100: Slider 110: Pressing portion SA: Sliding area _H1 , _H2 , _H3 : Height

Claims (10)

A variable resistor comprises: a first substrate; a plurality of comb teeth patterns supporting the first substrate and extending with spaces therebetween; and an insulator disposed on the first substrate to fill the spaces between the comb teeth patterns; the comb teeth patterns having front faces on the side opposite to the first substrate; the front faces being exposed from the insulator; the insulator comprising: a first intervening portion positioned between the comb teeth patterns; and a second intervening portion positioned between the first substrate and the comb teeth pattern. The variable resistor of claim 1, wherein: the insulator has a first main surface on the opposite side of the first substrate; the height of the front end surface relative to the first substrate is substantially the same as the height of the first main surface relative to the first substrate. The variable resistor of claim 1, wherein: the insulator has a first principal surface opposite to the first substrate; the first principal surface extends substantially parallel to the first substrate. The variable resistor as claimed in claim 1, wherein: the insulator has a first principal surface opposite to the first substrate; the variable resistor includes an impedance element; the plurality of comb-tooth patterns include a plurality of first comb-tooth patterns connected to the impedance element; the first comb-tooth pattern includes: a first portion whose front end face is exposed from the insulator; and a second portion integrally formed with the first portion and connected to the impedance element; the second portion is thinner than the first portion in a first direction perpendicular to the first principal surface. The variable resistor as recited in claim 1, comprising: an impedance element disposed on the first substrate; a first wiring pattern disposed on the first substrate and connected to the impedance element; a spacer having an opening; a second substrate laminated on the first substrate via the spacer; a connector disposed on the second substrate within the opening and electrically connected to the impedance element by pressing a slider from the outside of the second substrate; the second wiring pattern disposed on the second substrate and connected to the connector, or disposed on the first substrate and electrically connected to the connector by pressing the slider; wherein, in a top view, the connector has a non-overlapping region that does not overlap with the impedance element; In a top view, the non-overlapping area includes a sliding area in which the slider can slide. The front end surface is the surface of the comb pattern facing the connector. The resistance between the first wiring pattern and the second wiring pattern can be varied in response to the position of the slider. The variable resistor as recited in claim 5, wherein: the second wiring pattern is disposed on the second substrate and connected to the connector; the plurality of comb-tooth patterns include a plurality of first comb-tooth patterns connected to the resistor; the first comb-tooth pattern overlaps the sliding region in a top view; the connector contacts the first comb-tooth pattern by pressing the slider from an outer side of the second substrate. The variable resistor as recited in claim 5, wherein: the second wiring pattern is disposed on the first substrate; the plurality of comb-tooth patterns include a plurality of first comb-tooth patterns connected to the resistor; in a top view, the first comb-tooth pattern and the second wiring pattern overlap the sliding region; the connector contacts the first comb-tooth pattern and the second wiring pattern by pressing the slider from an outer side of the second substrate. The variable resistor as recited in claim 5, wherein: the second wiring pattern is disposed on the first substrate; the plurality of comb-tooth patterns include: a plurality of first comb-tooth patterns connected to the resistor; and a plurality of second comb-tooth patterns connected to the second wiring pattern; in a top view, the first and second comb-tooth patterns overlap with the sliding region; the first comb-tooth pattern and the second comb-tooth pattern are arranged relative to each other in the sliding region along an extending direction of the connector; the connector contacts the first and second comb-tooth patterns by pressing the slider from the first substrate. The variable resistor as recited in claim 5, wherein: the variable resistor is disposed on the first substrate and further comprises a third wiring pattern connected to the resistor; the plurality of comb-tooth patterns include: a third comb-tooth pattern connected to the first wiring pattern; and a fourth comb-tooth pattern connected to the third wiring pattern; in a top view, the third and fourth comb-tooth patterns overlap with the sliding region. A method for manufacturing a variable resistor according to any one of claims 1 to 9 comprises: Step 1: Preparing a support having a release-treated surface; Step 2: Forming the comb-tooth pattern on the release-treated surface of the support; Step 3: Forming the insulator on the release-treated surface to fill the gaps between the comb-tooth pattern; and Step 4: Transferring the comb-tooth pattern and the insulator from the support to the first substrate.