Variable resistor and method for manufacturing variable resistor

Abstract

In the present invention, a variable resistor 1A comprises a base material 11, a plurality of comb teeth patterns 45a–45j that are supported by the base material 11 and extend with gaps therebetween, and a first resist layer 20 that is positioned on the base material 11 so as to fill in the spaces between the comb teeth patterns 45a–45j. The comb teeth patterns 45a–45j have upper surfaces 46 on the opposite side from the base material 11, the upper surfaces 46 being exposed from the first resist layer 20.

Description

Variable resistor and method for manufacturing the same

[0001] The present invention relates to a variable resistor and a method for manufacturing the same. For designated countries where incorporation by reference of literature is permitted, the content of Japanese Patent Application No. 2022-211822 filed in Japan on December 28, 2022 is incorporated by reference into this specification and made a part of the description of this specification.

[0002] The variable resistor disclosed in Patent Document 1 includes a resistor disposed on the upper surface of a lower membrane substrate, a plurality of comb-tooth patterns connected to the resistor and arranged at intervals from one another, and a connector disposed on the lower surface of the upper membrane substrate, and when the upper membrane substrate and the connector are bent downward by the pressure of the slider, the connector comes into contact with the comb-tooth patterns (see, for example, Patent Document 1 (paragraph

[0090] , Figures 8 to 12)). When the slider slides while pressing against the upper membrane substrate, the comb-tooth patterns electrically connected to the connectors change sequentially, and the resistance length (resistance value) of the resistor changes (see, for example, Patent Document 1 (paragraph

[0092] , Figure 9)).

[0003] International Publication No. 2021 / 205899

[0004] In the above-described conventional technology, because there are spaces between the comb tooth patterns, when the slider slides while pressing against the upper membrane substrate, the connectors that enter the spaces come into contact with the comb tooth patterns from the sides. Therefore, repeated sliding can cause the comb tooth patterns to be scraped off due to repeated lateral contact of the connectors with the comb tooth patterns, or the lateral force can cause the comb tooth patterns to fall over and peel off from the lower membrane substrate. In such cases, repeated sliding can cause the comb tooth patterns to deteriorate.

[0005] An object of the present invention is to provide a variable resistor that can suppress deterioration of the comb-tooth pattern, and a method for manufacturing the variable resistor.

[0006] [1] Aspect 1 of the present invention comprises a first substrate, a plurality of comb-tooth patterns supported by the first substrate and extending at intervals from one another, and an insulator disposed on the first substrate so as to fill spaces between the comb-tooth patterns, wherein the comb-tooth patterns have a tip surface opposite the first substrate, and the tip surface is a variable resistor exposed from the insulator.

[0007] [2] A second aspect of the present invention may be a variable resistor according to the first aspect, wherein the insulator has a first main surface opposite to the first substrate, and the height of the tip end surface from the first substrate is substantially the same as the height of the first main surface from the first substrate.

[0008] [3] A third aspect of the present invention may be a variable resistor according to the first or second aspect, wherein the insulator has a first main surface opposite to the first substrate, and the first main surface extends substantially parallel to the first substrate.

[0009] [4] A fourth aspect of the present invention may be a variable resistor according to any one of the first to third aspects, wherein 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.

[0010] [5] Aspect 5 of the present invention may be a variable resistor according to any one of Aspects 1 to 4, wherein the insulator has a first main 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 patterns including a first portion whose tip surface is exposed from the insulator and a second portion formed integrally with the first portion and connected to the resistor, and the thickness of the second portion in a first direction perpendicular to the first main surface may be thinner than the thickness of the first portion.

[0011] [6] Aspect 6 of the present invention is the variable resistor of any one of Aspects 1 to 5, wherein the variable resistor comprises: a resistor disposed on the first substrate; a first wiring pattern disposed on the first substrate and connected to the resistor; a spacer having an opening; a second substrate laminated on the first substrate via the spacer; a connector disposed on the second substrate to be located within the opening and electrically connected to the resistor when a slider is pressed from outside the second substrate; and a 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 when the slider is pressed, wherein the connector has a non-overlapping region that does not overlap with the resistor in a planar view; a sliding region in which the slider can slide is included in the non-overlapping region in a planar view; and the tip surface is a surface of the comb-tooth pattern that faces the connector; and a resistance value between the first wiring pattern and the second wiring pattern changes depending on the position of the slider.

[0012] [7] A seventh aspect of the present invention may be a variable resistor according to the sixth aspect, 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 patterns overlap the sliding region in a plan view, and the connector comes into contact with the first comb-tooth patterns when the slider is pressed from outside the second substrate.

[0013] [8] Aspect 8 of the present invention may be a variable resistor according to aspect 6, 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, the first comb-tooth patterns and the second wiring pattern overlap with the sliding region in a planar view, and the connector contacts the first comb-tooth patterns and the second wiring pattern when the slider is pressed from outside the second substrate.

[0014] [9] A ninth aspect of the present invention may be a variable resistor according to the sixth aspect, 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, the first and second comb-tooth patterns overlap with the sliding region in a planar view, the first comb-tooth patterns and the second comb-tooth patterns are alternately arranged in the sliding region along the extension direction of the connector, and the connector comes into contact with the first and second comb-tooth patterns by the pressure of the slider from the first substrate.

[0015]

[10] Aspect 10 of the present invention is a variable resistor according to any one of aspects 6 to 9, wherein the variable resistor further comprises a third wiring pattern disposed on the first substrate and connected to the resistor, the plurality of comb tooth patterns including a third comb tooth pattern connected to the first wiring pattern and a fourth comb tooth pattern connected to the third wiring pattern, and the third and fourth comb tooth patterns may overlap the sliding region in a planar view.

[0016]

[11] Aspect 11 of the present invention is a method for manufacturing a variable resistor according to any one of Aspects 1 to 10, comprising: 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 so as to fill the spaces between the comb-tooth patterns; and a fourth step of transferring the comb-tooth pattern and the insulator from the support to the first substrate.

[0017] In the present invention, deterioration of the comb tooth pattern can be suppressed by filling the spaces between the comb tooth patterns with an insulator and exposing the tip surface of the comb tooth pattern opposite the first substrate from the insulator.

[0018] FIG. 1 is a plan view showing a variable resistor according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1. FIG. 5 is a cross-sectional view taken along line VV in FIG. 1. FIG. 6 is a plan view showing a lower membrane substrate of a variable resistor according to a first embodiment of the present invention. FIG. 7 is a bottom view showing a spacer and an upper membrane substrate of a variable resistor according to a first embodiment of the present invention. FIGS. 8A to 8D are cross-sectional views showing an example of a manufacturing method for a variable resistor according to a first embodiment of the present invention. FIGS. 9A to 9D are cross-sectional views showing an example of a manufacturing method for a variable resistor according to a first embodiment of the present invention. FIG. 10 is a plan view showing a variable resistor according to a second embodiment of the present invention. FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 10. FIG. 12 is a plan view showing a lower membrane substrate of a variable resistor according to a second embodiment of the present invention. FIG. 13 is a bottom view showing a spacer and an upper membrane substrate of a variable resistor according to a second embodiment of the present invention. Fig. 14 is a plan view showing a variable resistor according to a third embodiment of the present invention. Fig. 15 is a cross-sectional view taken along line XV-XV in Fig. 14. Fig. 16 is a plan view showing a lower membrane substrate of the variable resistor according to the third embodiment of the present invention.

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0020] <<First Embodiment>> Fig. 1 is a plan view showing a variable resistor 1A in the first embodiment, Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1, Fig. 3 is a cross-sectional view taken along line III-III in Fig. 1, Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 1, and Fig. 5 is a cross-sectional view taken along line VV in Fig. 1. Also, Fig. 6 is a plan view showing a lower membrane substrate 10A of the variable resistor 1A in the first embodiment, and Fig. 7 is a bottom view showing a spacer 90 and an upper membrane substrate 60A of the variable resistor 1A in the first embodiment.

[0021] As shown in Figures 1 to 7, the variable resistor 1A in this embodiment comprises a lower membrane substrate 10A (see Figures 2 to 6), an upper membrane substrate 60A (see Figures 2 to 5 and Figure 7), a spacer 90, and a slider 100.

[0022] The lower membrane substrate 10A has a resistor 40, a plurality of (ten in this example) comb-tooth patterns 45a to 45j, and wiring patterns 31 and 35. In this embodiment, the plurality of comb-tooth patterns 45a to 45j may be collectively referred to as "comb-tooth patterns 45."

[0023] On the other hand, the upper membrane substrate 60A has a connector 80 that electrically connects the resistor 40 and the wiring pattern 70. These membrane substrates 10A, 60A are stacked via a spacer 90, which ensures a gap between the membrane substrates 10A, 60A. The slider 100 is configured to slide on the upper membrane substrate 60A while pressing against it in the sliding area SA (see FIG. 1 ). The pressure of the slider 100 electrically connects the resistor 40 and the wiring pattern 70 via the connector 80 and the comb-tooth pattern 45.

[0024] In this variable resistor 1A, the slider 100 slides while pressing against the upper membrane substrate 60A, thereby sequentially changing the comb-tooth pattern 45 with which the connector 80 comes into contact. This changes the electrical connection position between the connector 80 and the resistor 40, making it possible to change the resistance length (resistance value) of the resistor 40. Examples of uses of this variable resistor 1A include variable resistance elements, position sensors, switches, and encoders. Note that the uses of the variable resistor 1A of this embodiment are not particularly limited to those described above.

[0025] The configuration of the variable resistor 1A of this embodiment will be described in detail below.

[0026] As shown in FIG. 6, the lower membrane substrate 10A is a wiring board including a substrate 11, a first resist layer 20, wiring patterns 31 and 35, a resistor 40, a comb-tooth pattern 45, and a second resist layer 50. The substrate 11 in this embodiment corresponds to an example of the "first substrate" in the present invention, the first resist layer 20 in this embodiment corresponds to an example of the "insulator" in the present invention, the comb-tooth patterns 45a to 45j in this embodiment correspond to an example of the "comb-tooth pattern," the comb-tooth pattern 45a in this embodiment corresponds to an example of the "third comb-tooth pattern" in the present invention, the comb-tooth patterns 45b to 45i in this embodiment correspond to an example of the "first comb-tooth pattern," and the comb-tooth pattern 45j in this embodiment corresponds to an example of the "fourth comb-tooth pattern" in the present invention. The wiring pattern 31 in this embodiment corresponds to an example of the "first wiring pattern" in the present invention, and the wiring pattern 35 in this embodiment corresponds to an example of the "third wiring pattern" in the present invention.

[0027] The substrate 11 is a film-like member made of a flexible and electrically insulating material. Examples of materials that make up the substrate 11 include resin materials, and more specifically, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). More specifically, an adhesive tape having an adhesive layer on one main surface of a PET film can be used as the substrate 11. Alternatively, a hot melt adhesive or the like can be used instead of the adhesive layer. The substrate 11 does not have to be flexible.

[0028] The first resist layer 20 is provided on the upper surface 12 of the substrate 11. The first resist layer 20 is formed by solidifying (curing) an electrically insulating resist material. Specific examples of the resist material include resin materials such as epoxy resin, urethane resin, polyester resin, and acrylic resin.

[0029] 2 and 6, the first resist layer 20 has a thin portion 21 and a protruding portion 22. As shown in Fig. 6, the thin portion 21 surrounds the protruding portion 22 and is relatively thin compared to the protruding portion 22.

[0030] The thin portion 21 overlaps the second resist layer 50 in a plan view (plan view when the variable resistor 1A is viewed from above or below (in the normal direction to the main surface of the variable resistor 1A (Z direction in the figure))) and is not exposed from the second resist layer 50. Also, as shown in FIG. 3 , the thin portion 21 is not directly covered by the second resist layer 50, but has portions that are indirectly covered by the second resist layer 50 via the wiring patterns 31, 35, the resistor 40, and the comb-tooth pattern 45.

[0031] 2 and 6, the protruding portion 22 in this embodiment is surrounded by the thin portion 21. This protruding portion 22 does not overlap with the second resist layer 50 in a plan view and is exposed from the second resist layer 50. As shown in FIG. 2, the thickness of the protruding portion 22 is relatively thicker than the thickness of the thin portion 21, and the upper surface 22a of the protruding portion 22 protrudes upward (in the +Z direction in the figure) from the upper surface 21a of the thin portion 21. As a result, the protruding portion 22 fills the opening 51 of the second resist layer 50. The upper surface 22a of the protruding portion 22 in this embodiment corresponds to an example of the "first main surface" in the present invention.

[0032] The upper surface 22a of the protrusion 22 is substantially parallel to the upper surface 12 of the substrate 11. The height H of the upper surface 22a from the substrate 11 １ is the height H of the upper surface 50a of the second resist layer 50 from the substrate 11 ２ is substantially the same as (H １ = H ２ ), the upper surfaces 22a and 50a are substantially flush with each other.

[0033] 2, 3, and 6, a comb-tooth pattern 45 is embedded in the first resist layer 20, extending from the thin portion 21 to the protruding portion 22. The first resist layer 20 further includes a plurality of (nine in this example) first intervening portions 23, a plurality of (ten in this example) second intervening portions 24, and a plurality of (two in this example) third intervening portions 25 around the comb-tooth pattern 45. As shown in FIG. 2, in the first resist layer 20 of this embodiment, a plurality of first intervening portions 23 and a plurality of second intervening portions 24 are alternately arranged along the X direction between the third intervening portions 25. The number of first and second intervening portions 23, 24 is not particularly limited and varies depending on the number of comb-tooth patterns 45.

[0034] 6, the first intervening portion 23 is located between the comb-tooth patterns 45 so as to fill the space between the comb-tooth patterns 45. The first intervening portion 23 extends from the thin portion 21 of the first resist layer 20 to the protruding portion 22 along the extending direction of the comb-tooth patterns 45 (the Y direction in the figure).

[0035] 5, the first interposed 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 and the first and second non-exposed portions 23b, 23c are integrally formed with each other.

[0036] The first exposed portion 23a constitutes a part of the protruding portion 22, and is exposed from the second resist layer 50. The upper surface 22a of the protruding portion 22 in the first exposed portion 23a is substantially flush with the upper surface 50a of the second resist layer 50. The surface roughness Ra of the upper surface 22a of the protruding portion 22 in the first exposed portion 23a can be, for example, 0.01 μm to 0.1 μm.

[0037] The first and second unexposed portions 23b, 23c constitute part of the thin portion 21. The first unexposed portion 23b is located between the first exposed portion 23a and the resistor 40. The upper surface 21a of the thin portion 21 in the first unexposed portion 23b is covered with the second resist layer 50. Therefore, the first unexposed portion 23b is interposed between the second resist layer 50 and the substrate 11.

[0038] The second unexposed portion 23c is connected to the first unexposed portion 23b. The upper surface 21a of the thin portion 21 in the second unexposed portion 23c is covered with the resistor 40. Therefore, the second unexposed portion 23c is interposed between the resistor 40 and the substrate 11.

[0039] In this embodiment, the thickness T of the first exposed portion 23a １ is the thickness T of the first non-exposed portion 23b ２ and the thickness T ２ is the thickness T of the second non-exposed portion 23c ３ It is thicker than １ >T ２ >T ３ ). Therefore, in the first interposed portion 23 of this embodiment, a step is formed between the first exposed portion 23a and the first unexposed portion 23b, and a step is also formed between the first unexposed portion 23b and the second unexposed portion 23c. Therefore, the thickness of the first interposed portion 23 gradually decreases toward the end of the comb-tooth pattern 45 on the resistor 40 side (toward the -Y direction in the figure). Note that the thickness in this embodiment refers to the thickness in a direction perpendicular to the upper surface 12 of the substrate 11 (the Z direction in the figure), and the Z direction in this embodiment corresponds to an example of the "first direction" in the present invention.

[0040] 2 and 3 , the second interposition portion 24 is located between the lower surface 47 of the comb-tooth pattern 45 and the upper surface 12 of the substrate 11. The second interposition portion 24 in this embodiment is located between the two first interposition portions 23, 23, and has a rectangular parallelepiped shape with the same width as the comb-tooth pattern 45.

[0041] In this way, by positioning the second intervening portion 24 between the comb-tooth pattern 45 and the substrate 11, the adhesive strength of the comb-tooth pattern 45 to the substrate 11 can be improved, thereby suppressing deterioration of the comb-tooth pattern 45. Furthermore, the second intervening portion 24 can also suppress the intrusion of water vapor and the like from the substrate 11 side, thereby suppressing deterioration of the comb-tooth pattern 45.

[0042] 2, the third intervening portion 25 is located between the second resist layer 50 and the comb tooth patterns 45a, 45j. The third intervening portion 25 also constitutes part of the protruding portion 22 and is exposed from the second resist layer 50. The upper surface of this third intervening portion 25 is included in the upper surface 22a of the protruding portion 22 and is substantially flush with the upper surface 50a of the second resist layer 50. The surface roughness Ra of the upper surface 22a of the protruding portion 22 in the third intervening portion 25 can be, for example, 0.01 μm to 0.1 μm.

[0043] As shown in FIG. 3 , the wiring patterns 31 and 35 are provided on the thin portion 21 of the first resist layer 20. The wiring patterns 31 and 35 are formed by solidifying (curing) a conductive paste. The conductive paste is composed of conductive particles and a binder resin mixed with water or a solvent and various additives. The conductive paste that constitutes the wiring patterns 31 and 35 is a low-resistance conductive paste having a relatively small electrical resistance value. Note that the method for forming the wiring patterns 31 and 35 is not particularly limited to the above.

[0044] Specific examples of conductive particles include silver, copper, nickel, tin, bismuth, zinc, indium, palladium, and alloys thereof. Specific examples of binder resins include acrylic resin, polyester resin, epoxy resin, vinyl resin, urethane resin, phenolic resin, polyimide resin, silicone resin, and fluororesin. Examples of solvents contained in the conductive paste include α-terpineol, butyl carbitol acetate, butyl carbitol, 1-decanol, butyl cellosolve, diethylene glycol monoethyl ether acetate, and tetradecane.

[0045] Although not particularly limited, in this embodiment, a silver paste containing silver as the main component of conductive particles or a copper paste containing copper as the main component of conductive particles is used as the low-resistance conductive paste. Metal salts may be used as the conductive particles contained in the conductive paste. Examples of metal salts include salts of the metals described above. The binder resin may be omitted from the conductive paste. Instead of the conductive paste, a conductive ink may be used.

[0046] 6, the wiring patterns 31 and 35 in this embodiment are connected to both ends of the resistor 40. The wiring patterns 31 and 35 in this embodiment extend in the X direction in the drawing, which is substantially parallel to the resistor 40, but are not limited to this and may extend in a direction other than the X direction, such as the Y direction.

[0047] 3 and 6, the resistor 40 is provided between the wiring patterns 31 and 35 and extends in the X direction in the drawings. Similar to the wiring patterns 31 and 35, the resistor 40 is also formed by hardening a conductive paste.

[0048] The conductive paste constituting this resistor 40 is a high-resistivity conductive paste having a higher electrical resistance value than the above-described low-resistivity conductive paste. The conductive paste constituting this resistor 40 contains conductive particles having a higher electrical resistivity than the conductive particles in the conductive paste constituting the above-described wiring patterns 31 and 35. That is, the resistor 40 is made of a material having a higher electrical resistivity than the material constituting the wiring patterns 31 and 35, and the resistance value of the resistor 40 is sufficiently higher than the resistance value of the wiring patterns 31 and 35 to the extent that the resistance value of the wiring patterns 31 and 35 can be ignored. Specifically, the resistance value of the resistor 40 is 10 times or more the resistance value of the wiring patterns 31 and 35, preferably 100 times or more the resistance value of the wiring patterns 31 and 35. Furthermore, the electrical resistivity of the material constituting the resistor 40 is 10 times or more the electrical resistivity of the material constituting the wiring patterns 31 and 35, preferably 100 times or more the electrical resistivity of the material constituting the wiring patterns 31 and 35.

[0049] 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.

[0050] As described above, the resistor 40 covers the end of one wiring pattern 31 and also covers the end of the other wiring pattern 35. The wiring patterns 31 and 35 are connected to each other by the resistor 40. Although not shown in the figure, the one wiring pattern 31 is connected to a power supply, while the other wiring pattern 35 is connected to ground.

[0051] Like the wiring patterns 31 and 35, the comb-tooth patterns 45a to 45j are formed by hardening a low-resistance conductive paste. That is, each of the comb-tooth patterns 45a to 45j is made of a material having a lower electrical resistivity than the material constituting the resistor 40, and the resistance of the resistor 40 is sufficiently higher than the resistance of each of the comb-tooth patterns 45a to 45j to the extent that the resistance of each of the comb-tooth patterns 45a to 45j can be ignored. Specifically, the resistance of the resistor 40 is 10 times or more, preferably 100 times or more, of the resistance of the comb-tooth patterns 45a to 45j. Furthermore, the electrical resistivity of the material constituting the resistor 40 is 10 times or more, preferably 100 times or more, of the electrical resistivity of the material constituting the comb-tooth patterns 45a to 45j.

[0052] 6, the comb-tooth pattern 45a on the left side of the drawing branches off from the wiring pattern 31 and protrudes in the Y direction. That is, this comb-tooth pattern 45a is connected to the wiring pattern 31 and extends below the sliding area SA (see FIG. 1). Similarly, the comb-tooth pattern 45j on the right side of the drawing branches off from the wiring pattern 35 and protrudes in the Y direction. That is, this comb-tooth pattern 45j is connected to the wiring pattern 35 and extends below the sliding area SA (see FIG. 1).

[0053] In contrast, as shown in FIG. 3, the eight comb tooth patterns 45b to 45i located between the comb tooth patterns 45a and 45j at both ends are electrically connected to the resistor 40 by having their ends embedded in the resistor 40. As shown in FIG. 6, these comb tooth patterns 45b to 45i protrude from the resistor 40 in the +Y direction. That is, the comb tooth patterns 45b to 45i are connected to the resistor 40 and extend below the sliding area SA (see FIG. 1). The comb tooth patterns 45a and 45j at both ends may be embedded in the resistor 40, similar to the comb tooth patterns 45b to 45i, rather than branching off from the wiring patterns 31 and 35.

[0054] Each of the comb tooth patterns 45a to 45j extends along the Y direction in the figure, and the planar shape of the comb tooth patterns 45a to 45j is linear. The multiple comb tooth patterns 45a to 45j are arranged substantially parallel to one another. The multiple comb tooth patterns 45a to 45j are also arranged at substantially equal intervals. The number of comb tooth patterns 45 is not limited to the above. Incidentally, as will be described later, the greater the number of comb tooth patterns 45, the higher the output resolution of the variable resistor 1A. As long as intervals are maintained between the comb tooth patterns 45a to 45j, the intervals between the comb tooth patterns 45a to 45j are not limited to being equal.

[0055] 4, the comb tooth patterns 45b to 45i include a second exposed portion 48a, a third unexposed portion 48b, and a fourth unexposed portion 48c. The second exposed portion 48a and the third and fourth unexposed portions 48b, 48c are integrally formed with each other. The second exposed portion 48a in this embodiment corresponds to an example of the "first portion" in the present invention, and the fourth unexposed portion 48c in this embodiment corresponds to an example of the "second portion" in the present invention.

[0056] The second exposed portion 48a is located between the first intervening portions 23. In this second exposed portion 48a, the upper surfaces 46 of the comb tooth patterns 45b to 45i are exposed from the first intervening portions 23 of the first resist layer 20. In addition, this upper surface 46 is not covered by the second resist layer 50. Note that the upper surface 46 in this embodiment corresponds to an example of the "tip surface" in the present invention.

[0057] In this embodiment, the height H of the upper surface 46 from the substrate 11 ３ is the height H of the upper surfaces 22a and 50a. １ , H ２ is substantially the same as (H １ = H ２ = H ３ In other words, the upper surfaces 46, 22a, and 50a are substantially flush with each other. The surface roughness Ra of the upper surface 46 of the comb-tooth patterns 45b to 45i in the second exposed portion 48a can be set to, for example, 0.01 μm to 0.1 μm.

[0058] 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.

[0059] The third unexposed portion 48b is located between the second exposed portion 48a and the resistor 40. The upper surface 46 of the third unexposed portion 48b is covered with the second resist layer 50. Therefore, the third unexposed portion 48b is interposed between the second resist layer 50 and the second interposed portion 24 of the first resist layer 20.

[0060] The fourth unexposed portion 48c is located between the third unexposed portion 48b and the resistor 40. The upper surface 46 of the fourth unexposed portion 48c is covered by the resistor 40. Therefore, the fourth unexposed portion 48c is interposed between the resistor 40 and the second interposed portion 24 of the first resist layer 20.

[0061] In this embodiment, the thickness T of the second exposed portion 48a ４ is the thickness T of the third non-exposed portion 48b ５ and the thickness T ５is the thickness T of the fourth non-exposed portion 48c ６ It is thicker than ４ >T ５ >T ６ ). Therefore, in the comb-tooth patterns 45b to 45i of this embodiment, a step is formed between the second exposed portion 48a and the third unexposed portion 48b, and a step is also formed between the third unexposed portion 48b and the fourth unexposed portion 48c. Therefore, the thickness of the comb-tooth patterns 45b to 45i becomes thinner in stages in the -Y direction in the figure.

[0062] On the other hand, the cross-sectional shapes of comb tooth patterns 45a and 45j located at the left and right ends of comb tooth pattern 45 are slightly different from the cross-sectional shapes of comb tooth patterns 45b to 45i. Although not particularly shown, since resistor 40 is not interposed between comb tooth patterns 45a and 45j and second resist layer 50, comb tooth patterns 45a and 45j do not have fourth unexposed portion 48c, and third unexposed portion 48b extends from second exposed portion 48a to wiring patterns 31 and 35.

[0063] The second resist layer 50 is formed by solidifying (curing) a resist material, similar to the first resist layer 20. Examples of this resist material include resin materials such as epoxy resin, urethane resin, polyester resin, and acrylic resin.

[0064] 2 to 4, the second resist layer 50 covers the thin portion 21 of the first resist layer 20, the wiring patterns 31 and 35, the resistor 40, and the third unexposed portion 48b of the comb-tooth pattern 45. The second resist layer 50 has an opening 51, which surrounds the periphery of the protruding portion 22 of the first resist layer 20.

[0065] 7, the upper membrane substrate 60A is a wiring board including a substrate 61, a wiring pattern 70, and a connector 80. The substrate 61 in this embodiment corresponds to an example of a "second substrate" in the present invention, and the wiring pattern 70 in this embodiment corresponds to an example of a "second wiring pattern" in the present invention.

[0066] Like the substrate 11 described above, the substrate 61 is a film-like member made of a flexible and electrically insulating material. Examples of materials that can be used for the substrate 11 include resin materials, and more specifically, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). The material that can be used for the substrate 61 is not particularly limited to the above. The substrate 61 may be made of a plate material made of a conductive material such as a metal material. In this case, the substrate 61 may also function as the connector 80. The substrate 61 may also function as the wiring pattern 70. Even when the substrate 61 is made of a conductive plate material, the connector 80 and the wiring pattern 70 may be formed on the substrate 61 separately from the substrate 61.

[0067] The wiring pattern 70 is formed by printing a low-resistivity conductive paste on the lower surface 62 of the substrate 61 and then curing it. That is, the wiring pattern 70 is made of a material having an electrical resistivity lower than that of the material constituting the resistor 40, and the resistance value of the resistor 40 is sufficiently higher than that of the wiring pattern 70 to the extent that the resistance value of the wiring pattern 70 can be ignored. Specifically, the resistance value of the resistor 40 is 10 times or more, preferably 100 times or more, the resistance value of the wiring pattern 70. Furthermore, the electrical resistivity of the material constituting the resistor 40 is 10 times or more, preferably 100 times or more, the electrical resistivity of the material constituting the wiring pattern 70. Note that the method for forming the wiring pattern 70 is not particularly limited to the above.

[0068] A connector 80 is directly connected to the wiring pattern 70. The connector 80 includes a first main body 81 and a first protective layer 82. Note that the connector 80 does not necessarily have to include the first protective layer 82.

[0069] The first body portion 81 is provided on the lower surface 62 of the substrate 61. Like the wiring patterns 31 and 35 described above, the first body portion 81 is formed by printing and curing a low-resistance conductive paste. That is, the first body portion 81 is made of a material having a lower electrical resistivity than the material constituting the resistor 40, and the resistance value of the resistor 40 is sufficiently higher than the resistance value of the first body portion 81 to the extent that the resistance value of the first body portion 81 can be ignored. Specifically, the resistance value of the resistor 40 is 10 times or more, preferably 100 times or more, the resistance value of the first body portion 81. Furthermore, the electrical resistivity of the material constituting the resistor 40 is 10 times or more, preferably 100 times or more, the electrical resistivity of the material constituting the first body portion 81.

[0070] On the other hand, the first protective layer 82 is a layer that protects the first main body portion 81, and is formed by printing and curing a high-resistance conductive paste. The first protective layer 82 is provided on the lower surface 62 of the substrate 61 so as to cover the entire first main body portion 81.

[0071] As shown in FIG. 1, the connector 80 is provided on the lower surface 62 of the base material 61 so as to partially overlap the comb-tooth pattern 45 of the lower membrane substrate 10A in plan view.

[0072] The spacer 90 is a film-like member made of a flexible and electrically insulating material, similar to the above-described base materials 11 and 61. Examples of materials that can be used to make the spacer 90 include resin materials, and more specifically, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN).

[0073] As shown in FIGS. 1 to 5 and 7 , the spacer 90 has an opening 91 with a rectangular planar shape. The opening 91 is larger than the connector 80 and is large enough to accommodate the connector 80. In this embodiment, the opening 91 is large enough to accommodate not only the connector 80 but also the comb-tooth pattern 45. The opening 91 is formed in the spacer 90 so as to accommodate the connector 80 and the comb-tooth pattern 45 when the membrane substrates 10A, 60A are stacked with the spacer 90 interposed therebetween. It is sufficient that at least a portion of the connector 80 is located within the opening 91 of the spacer 90, and a portion of the connector 80 may extend outside the opening 91 and be interposed between the spacer 90 and the substrate 61.

[0074] As described above, the membrane substrates 10A, 60A are stacked via the spacer 90. At this time, as shown in Figures 2 to 5, the membrane substrates 10A, 60A are stacked so that the lower surface 62 of the base material 61 of the upper membrane substrate 60A faces the upper surface 12 of the base material 11 of the lower membrane substrate 10A. Furthermore, the base material 11 of the lower membrane substrate 10A and the spacer 90 are bonded to each other via an adhesive layer (not shown), and the spacer 90 and the base material 61 of the upper membrane substrate 60A are also bonded to each other via an adhesive layer (not shown).

[0075] 1, the connector 80 and the comb-tooth pattern 45 are contained within the opening 91 in plan view. Furthermore, as shown in Fig. 4, the connector 80 and the comb-tooth pattern 45 face each other in cross section. In this embodiment, as shown in Fig. 1, the connector 80 has a non-overlapping region NA in which it does not overlap with the resistor 40 in plan view.

[0076] 2, 4, and 5, a spacer 90 ensures a gap between the connector 80 and the comb-tooth pattern 45. As will be described later, the base material 11 of the upper membrane substrate 60A is deformed by the pressure of the slider 100, and this deformation brings the connector 80 and the comb-tooth pattern 45 into contact with each other, thereby electrically connecting them.

[0077] In this embodiment, the thickness of the spacer 90 is set so that the connector 80 does not come into contact with the comb-tooth pattern 45 when not pressed, but is not limited to this. The thickness of the spacer 90 may also be set so that the connector 80 is always in contact with the comb-tooth pattern 45.

[0078] In this invention, the term "electrically connected" between the connector and the resistor means that the resistance between the connector and the comb-tooth pattern is below a predetermined threshold value, and does not include the state in which the connector and the comb-tooth pattern are simply in contact when not pressed, as described above.

[0079] The slider 100 is a member having a semi-cylindrical pressing portion 110 at its tip, and is made of, for example, a metal material. The configuration of the slider 100 is not particularly limited to the above, as long as it is configured to slide while pressing against the top surface 63 of the base material 61 of the upper membrane substrate 60A. In this embodiment, the object that the slider 100 presses against is the top surface 63 of the base material 61 of the upper membrane substrate 60A, so the slider 100 may be made of an electrically insulating material such as a resin material. As will be described later, the slider 100 may be replaced with an operator's finger.

[0080] The slider 100 is movably held in a housing (not shown) or the like that houses the variable resistor 1A. The slider 100 is capable of reciprocating along the X direction in the figure (the extension direction (longitudinal direction) of the connector 80) while maintaining a constant pressure with the pressing portion 110 pressed against the upper surface 63 of the base material 61 of the upper membrane substrate 60A with a predetermined pressing force. In this embodiment, as shown in FIG. 1 , the sliding area SA on which the slider 100 can slide is included in the non-overlapping area NA of the connector 80 in a plan view and does not overlap with the resistor 40. The entire area of ​​the connector 80 constitutes the non-overlapping area NA. The slider 100 is capable of reciprocating along the X direction in the figure within the sliding area SA. The sliding area SA in this embodiment corresponds to an example of a "sliding area" in the present invention.

[0081] 2, when the slider 100 is pressed, the base material 61 of the upper membrane substrate 60A bends downward, and the connector 80 comes into contact with the comb-tooth pattern 45. This electrically connects the resistor 40 and the wiring pattern 70 via the connector 80. Specifically, in the state shown in FIG. 2, the comb-tooth pattern 45f among the comb-tooth patterns 45a to 45j is electrically connected to the connector 80.

[0082] The number of comb-tooth patterns 45a to 45j that are simultaneously connected to the connector 80 by the pressure of the slider 100 may be plural.

[0083] In this embodiment, as the slider 100 slides while pressing against the upper membrane substrate 60A, the comb tooth patterns 45 connected by the connectors 80 change sequentially, and the resistance length (resistance value) of the resistor 40 changes.

[0084] 2, as described above, the comb-tooth pattern 45f is connected via the connector 80. As the slider 100 slides in the +X direction in the figure from this state, the comb-tooth patterns 45 connected via the connector 80 change in the following order: comb-tooth pattern 45f → comb-tooth pattern 45g → comb-tooth pattern 45h → comb-tooth pattern 45i → comb-tooth pattern 45j.

[0085] Accordingly, the wiring pattern 70 connected to the connector 80 detects a voltage (detection voltage) corresponding to the comb-tooth pattern 45 connected via the connector 80. That is, the resistance value between the wiring patterns 31 and 70 changes depending on the pressing position of the slider 100. When the slider 100 slides in the +X direction in the figure, the resistance value between the wiring patterns 31 and 70 gradually increases as the slider 100 slides. A multimeter or the like is connected to the wiring patterns 31 and 70 of this variable resistor 1A, and the multimeter or the like outputs the potential difference between the power supply voltage and the detection voltage of the wiring pattern 70.

[0086] 2, when the slider 100 slides in the −X direction in the figure, the combination of the comb-tooth patterns connected via the connector 80 changes as the slider 100 slides, from comb-tooth pattern 45f to comb-tooth pattern 45e to comb-tooth pattern 45d to comb-tooth pattern 45c to comb-tooth pattern 45b to comb-tooth pattern 45a. In this case, the resistance value between the wiring patterns 31 and 70 gradually decreases as the slider 100 slides.

[0087] For example, when the comb tooth pattern 45a at the left end in FIG. 2 is electrically connected to the wiring pattern 70 via the connector 80, a voltage of approximately the same potential as the power supply voltage is detected in the wiring pattern 70, and the multimeter or the like outputs the potential difference (e.g., 0 [V]) between the power supply voltage and the detected voltage of the wiring pattern 70.

[0088] In contrast, when the approximately intermediate comb tooth pattern 45f is electrically connected to the wiring pattern 70 via the connector 80, the wiring pattern 70 detects a voltage that is approximately half the potential of the power supply voltage, and the multimeter or the like outputs the potential difference between the power supply voltage and the detected voltage of the wiring pattern 70 (e.g., 2.5 V).

[0089] Furthermore, when the comb tooth pattern 45j at the right end in Figure 2 is electrically connected to the wiring pattern 70 via the connector 80, the wiring pattern 70 detects a voltage that is approximately the same potential as the ground, and the multimeter or the like outputs the potential difference (e.g., 5 [V]) between the power supply voltage and the detected voltage of the wiring pattern 70.

[0090] In this manner, in this embodiment, the output of the variable resistor 1A is stepped because the resistance value between the wiring patterns 31 and 70 changes depending on the comb-tooth pattern 45 connected via the connector 80. Therefore, the more the number of comb-tooth patterns 45 is increased and the narrower the pitch of the comb-tooth patterns 45 is, the higher the resolution of the output of the variable resistor 1A can be.

[0091] As described above, in this embodiment, the first intervening portions 23 of the first resist layer 20 fill the spaces between the comb-tooth patterns 45a to 45j, thereby reducing contact of the connector 80 with the side surfaces of the comb-tooth patterns 45a to 45j. This prevents the comb-tooth patterns 45a to 45j from being scraped off or from falling over due to a lateral force and peeling off from the lower membrane substrate, thereby preventing deterioration of the comb-tooth patterns 45a to 45j.

[0092] In addition, the comb tooth patterns 45a and 45j located at the left and right ends of the comb tooth pattern 45 can be protected not only by the first interposition portion 23 but also by the third interposition portion 25, thereby making it possible to suppress deterioration of the comb tooth patterns 45a and 45j.

[0093] Furthermore, in the above-described conventional technology, the amount of deflection of the upper membrane substrate and the connecting body when the connecting body is in contact with the upper surface of the comb-tooth pattern differs from the amount of deflection of the upper membrane substrate and the connecting body when the connecting body is inserted into the space between the comb-tooth patterns. This causes the slider to move not only in the sliding direction but also in the vertical direction, which can cause unstable electrical contact between the connecting body and the comb-tooth pattern. In such cases, the detection accuracy of the variable resistor (e.g., the linearity accuracy of the variable resistor's output value relative to the slider position) can be degraded.

[0094] In contrast to this, in this embodiment, when the slider 100 moves to a position corresponding to the space between the comb-tooth patterns 45, the downward movement of the connector 80 in the space between the comb-tooth patterns 45 (the −Z direction in the figure) can be reduced by the first interposition portion 23 and the third interposition portion 25, so that the downward movement of the slider 100 can be suppressed, and deterioration of the detection accuracy of the variable resistor can be suppressed.

[0095] In this embodiment, the height H of the upper surface 46 of the comb-tooth pattern 45 ３ and the height H of the upper surface 22a at the first and third intervening portions 23 and 25. ２Since these are substantially the same, the slider 100 can slide with almost no vertical movement, and deterioration of the detection accuracy of the variable resistor can be suppressed.

[0096] Furthermore, in this embodiment, the upper surface 46 of the comb-tooth pattern 45 and the upper surfaces 22 a of the first and third intervening portions 23, 25 are substantially parallel to each other, so that the slider 100 can slide with almost no movement in the vertical direction, thereby preventing deterioration in the detection accuracy of the variable resistor.

[0097] Next, a manufacturing method of the variable resistor 1A according to the first embodiment will be described with reference to the drawings. FIGS. 8A to 9D are cross-sectional views showing an example of a manufacturing method of the variable resistor 1A according to the first embodiment. The upper views of FIGS. 8A to 8D are cross-sectional views corresponding to the cross section taken along line II-II in FIG. 1, and the lower views of FIGS. 8A to 8D are cross-sectional views corresponding to the cross section taken along line III-III in FIG. 1. Similarly, the upper views of FIGS. 9A to 9D are cross-sectional views corresponding to the cross section taken along line II-II in FIG. 1, and the lower views of FIGS. 9A to 9D are cross-sectional views corresponding to the cross section taken along line III-III in FIG.

[0098] First, as shown in FIG. 8A , a release film 200 is prepared. The release film 200 in this embodiment includes a film 201 and a release layer 202 provided on one main surface of the film 201. The film 201 is made of a resin material. An example of this resin material is PET. The release layer 202 is formed by applying a release agent to the film 201. Examples of this release agent include a silicone-based release agent and a fluorine-based release agent. The release film 200 in this embodiment corresponds to an example of the "support" in the present invention, and the release layer 202 in this embodiment corresponds to an example of the "release-treated surface" in the present invention.

[0099] A resist material is printed on the release layer 202 of this release film 200 and solidified (cured) to form the second resist layer 50. At this time, as shown in the upper diagram of Figure 8 (A), the resist material is not applied to the area where the opening 51 is to be formed. In this way, the second resist layer 50 having the opening 51 can be formed.

[0100] The resist material may be printed using either a contact coating method or a non-contact coating method. Specific examples of contact coating methods include screen printing, gravure printing, offset printing, gravure offset printing, and flexographic printing. Specific examples of non-contact coating methods include inkjet printing, spray coating, dispense coating, and jet dispensing. The heat source for curing the resist material is not particularly limited, and examples include an electric heating oven, an infrared oven, a far-infrared oven (IR), a near-infrared oven (NIR), and a laser irradiation device, and a combination of these may also be used for heat treatment.

[0101] Next, as shown in the lower diagram of FIG. 8B , a high-resistance conductive paste is printed on the second resist layer 50 and solidified (cured), thereby forming the resistor 40. The conductive paste described above can be used as the high-resistance conductive paste. Methods for printing and solidifying the high-resistance conductive paste are not particularly limited, but examples include the same methods as those for printing and solidifying the second resist layer 50 described above.

[0102] 8C , a low-resistance conductive paste is printed from the inside of the opening 51 over the resistor 40 and then solidified (cured), thereby forming the comb-tooth pattern 45. The above-described conductive paste can be used as the low-resistance conductive paste. Methods for printing and solidifying the low-resistance conductive paste are not particularly limited, but examples thereof include the same methods as those for printing and solidifying the second resist layer 50 described above.

[0103] 8(D), a low-resistance conductive paste is printed on both ends of the resistor 40 to form wiring patterns 31 and 35. The above-described conductive paste can be used as the low-resistance conductive paste. The printing method and solidification method for the low-resistance conductive paste are not particularly limited, but examples thereof include the same methods as those for printing and solidification of the second resist layer 50 described above.

[0104] The order of the step of forming the comb-tooth pattern 45 in Fig. 8C and the step of forming the wiring patterns 31 and 35 in Fig. 8D may be reversed, or both steps may be performed in the same step.

[0105] 9A , a resist material is printed on the release film 200 so as to cover the wiring patterns 31 and 35, the resistor 40, the comb tooth pattern 45, and the second resist layer 50, and then solidified (cured), thereby forming the first resist layer 20. Examples of the resist material include the same resist material as that constituting the second resist layer 50 described above. Methods for printing and solidifying the resist material are not particularly limited, but examples include the same methods as those for printing and solidifying the second resist layer 50 described above.

[0106] At this time, the resist material is solidified while filling the spaces between the comb tooth patterns 45 and the spaces between the second resist layer 50 and the comb tooth pattern 45, thereby forming first intervening portions 23 that fill the spaces between the comb tooth patterns 45 and third intervening portions 25 that fill the spaces between the second resist layer 50 and the comb tooth pattern 45. Furthermore, the resist material is printed so as to cover the comb tooth pattern 45 and solidified, thereby forming the above-mentioned second intervening portions 24.

[0107] 9(B), the substrate 11 is attached to the first resist layer 20. As described above, for example, an adhesive tape having an adhesive layer (not shown) can be used as the substrate 11, and the substrate 11 is attached to the first resist layer 20 via the adhesive layer.

[0108] 9(C), the release film 200 is peeled off. In this manner, the above-described lower membrane substrate 10A is completed. That is, in the manufacturing method of the variable resistor 1A in this embodiment, the first and second resist layers 20, 50, the wiring patterns 31, 35, the resistor 40, and the comb-tooth pattern 45 are formed on the release film 200 and then transferred to the base material 11, thereby manufacturing the lower membrane substrate 10A.

[0109] With the lower membrane substrate 10A fabricated in this manner, the comb tooth pattern 45 and the first resist layer 20 are formed and transferred directly onto the release film 200, so that the upper surface 46 of the comb tooth pattern 45 can be easily exposed from the protruding portion 22 of the first resist layer 20 in which the comb tooth pattern 45 is embedded. For example, if an attempt is made to form the comb tooth pattern on the base material and then form the first resist layer, it is highly likely that the resist material will adhere to the upper surface of the comb tooth pattern, making it difficult to expose the upper surface of the comb tooth pattern.

[0110] Furthermore, since the upper surface 46 of the comb tooth pattern 45, the upper surface 22a of the protrusion 22 of the first resist layer 20 in which this comb 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, the upper surfaces 46, 22a, 50a can be easily formed flush.

[0111] Furthermore, since the surface shape of the highly smooth release film 200 can be transferred to the upper surfaces 46, 22a, 50a, the upper surfaces 46, 22a, 50a can be formed to be smooth. For example, the surface roughness Ra of the upper surfaces 46, 22a, 50a can be set to 0.01 μm to 0.1 μm.

[0112] 9(D), the upper membrane substrate 60A is attached to the lower membrane substrate 10A via the spacer 90. The wiring pattern 70 and connectors 80 of the lower membrane substrate 10A are formed by printing on the lower surface 62 of the base material 61, as described above. In this manner, the variable resistor 1A is manufactured.

[0113] In this embodiment, the first resist layer 20, the wiring patterns 31 and 35, the resistor 40, the comb-tooth pattern 45, and the second resist layer 50 of the lower membrane substrate 10A are formed on the release film 200 and transferred, but this is not limiting. At least the first resist layer 20 and the comb-tooth pattern 45 may be formed on the release film 200 and transferred onto the base material 11, and then the wiring patterns 31 and 35, the resistor 40, and the second resist layer 50 may be formed on the base material 11.

[0114] <<Second Embodiment>> Fig. 10 is a plan view showing a variable resistor 1B according to a second embodiment, and Fig. 11 is a cross-sectional view taken along line XI-XI in Fig. 10. Fig. 12 is a plan view showing a lower membrane substrate 10B of the variable resistor 1B according to the second embodiment. Fig. 13 is a bottom view showing a spacer 90 and an upper membrane substrate 60B of the variable resistor 1B according to the second embodiment.

[0115] 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 membrane substrate 10B rather than the upper membrane substrate 60B. However, the other configurations are the same as those of the first embodiment. Below, only the differences between the variable resistor 1B of the second embodiment and the first embodiment will be described, and the same components as those of the first embodiment will be assigned the same reference numerals and will not be described again.

[0116] 11 , the wiring pattern 70 of this embodiment is formed on a substrate 11 via a first resist layer 20. The wiring pattern 70 includes a second main body portion 71 and a second protective layer 72.

[0117] The second main body portion 71 is formed by printing and solidifying (curing) a low-resistance conductive paste, similar to the above-described wiring patterns 31 and 35. More specifically, the second main body portion 71 can be formed by printing and curing a low-resistance conductive paste on the second protective layer 72 formed inside the opening 51 of the second resist layer 50 in the step shown in FIG.

[0118] The second body portion 71 is made of a material having a lower electrical resistivity than the material making up the resistor 40, and the resistance value of the resistor 40 is sufficiently higher than the resistance value of the second body portion 71 to the extent that the resistance value of the second body portion 71 can be ignored. Specifically, the resistance value of the resistor 40 is 10 times or more, preferably 100 times or more, the resistance value of the second body portion 71. Furthermore, the electrical resistivity of the material making up the resistor 40 is 10 times or more, preferably 100 times or more, the electrical resistivity of the material making up the second body portion 71.

[0119] 12, the second main body portion 71 extends along the X direction in the figure. The second main body portion 71 has, at its end, a parallel portion 711 that extends substantially parallel to the resistor 40. The planar shape of the second main body portion 71 is not particularly limited to the above.

[0120] The second protective layer 72 of the wiring pattern 70 covers the parallel portion 711 of the second main body portion 71. This second protective layer 72 is a layer that protects the parallel portion 711 of the second main body portion 71, and is formed by printing and curing a high-resistance conductive paste that has a higher electrical resistance value than the above-mentioned low-resistance conductive paste. For example, this second protective layer 72 can be formed by printing and curing a high-resistance conductive paste inside the opening 51 of the second resist layer 50 in the process shown in FIG. 8B .

[0121] Specific examples of such high-resistivity conductive paste include, but are not limited to, carbon paste. The second protective layer 72 has a length approximately the same as the length of the resistor 40 in the X direction in the figure, and is disposed at a predetermined distance from the resistor 40 and the comb-tooth pattern 45. In other words, the second protective layer 72 of the wiring pattern 70 is disposed substantially parallel to the resistor 40 and also substantially parallel to the arrangement direction of the comb-tooth pattern 45. The wiring pattern 70 does not necessarily have to include the second protective layer 72.

[0122] 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 rectangular planar shape that is wider than the connector 80 of the first embodiment. In plan view, the connector 80 is provided on the lower surface 62 of the substrate 61 so that one edge 80 a of the connector 80 (the edge on the −Y side along the X direction in the figure) overlaps with the comb-tooth pattern 45, and the other edge 80 b of the connector 80 (the edge on the +Y side along the X direction in the figure) overlaps with the wiring pattern 70.

[0123] 11 , in the variable resistor 1B of this embodiment, when the slider 100 is pressed, the base material 61 of the upper membrane substrate 60B bends downward, and the connector 80 comes into contact with the comb-tooth pattern 45 and the wiring pattern 70, respectively, thereby electrically connecting the resistor 40 and the wiring pattern 70 via the connector 80. Then, when the slider 100 slides in the X direction while pressing against the upper membrane substrate 60B, the connection position between the connector 80 and the resistor 40 changes, and the resistance length (resistance value) of the resistor 40 changes.

[0124] Specifically, as described above, a power supply voltage (e.g., 5 V) is applied to one of the wiring patterns 31 connected to the resistor 40, while the other wiring pattern 35 connected to the resistor 40 is grounded. Furthermore, the wiring pattern 70 is constantly electrically connected to the resistor 40 via the connector 80 when the slider 100 is pressed, and the 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) that corresponds to the pressing position of the slider 100. That is, in this embodiment, the resistance value between the wiring patterns 31 and 70 changes depending on the pressing position of the slider 100. 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 detected voltage of the wiring pattern 70.

[0125] For example, when the slider 100 is located at the left end in the sliding area SA in FIG. 10, the connection position of the connector 80 of the resistor 40 is also located at the left end, so that the wiring pattern 70 detects a voltage with approximately the same potential as the power supply voltage, and a multimeter or the like outputs the potential difference (e.g., 0 [V]) between the power supply voltage and the detected voltage of the wiring pattern 70.

[0126] In contrast, as shown in FIG. 10 , when the slider 100 is positioned approximately in the center within the sliding area SA, the connection position of the connector 80 of the resistor 40 is also approximately in the center, so that the wiring pattern 70 detects a voltage that is approximately half the potential of the power supply voltage, and a multimeter or the like outputs the potential difference (e.g., 2.5 V) between the power supply voltage and the detected voltage of the wiring pattern 70.

[0127] Furthermore, when the slider 100 is located at the right end in the sliding area SA in FIG. 10, the connection position of the connector 80 of the resistor 40 is also located at the right end, so that the wiring pattern 70 detects a voltage at approximately the same potential as the ground, and a potential difference (e.g., 5 V) between the power supply voltage and the detected voltage of the wiring pattern 70 is output by a multimeter or the like.

[0128] In this second embodiment, the first intervening portion 23 fills the space between the comb tooth patterns 45, so that deterioration of the comb tooth patterns 45 can be suppressed as in the first embodiment, and deterioration of the detection accuracy of the variable resistor 1B can also be suppressed.

[0129] <<Third Embodiment>> Fig. 14 is a plan view showing a variable resistor 1C according to a third embodiment, and Fig. 15 is a cross-sectional view taken along line XV-XV in Fig. 14. Fig. 16 is a plan view showing a lower membrane substrate 10C of the variable resistor 1C according to the third embodiment.

[0130] As shown in Figures 14 to 16, the variable resistor 1C of this embodiment differs from the variable resistor 1B of the second embodiment in that (1) the lower membrane substrate 10C is provided with comb-tooth patterns 75a to 75i, and (2) the connector 80 does not overlap with the wiring pattern 70; however, the other configurations are the same as those of the second embodiment. Below, only the differences between the variable resistor 1C of the third embodiment and the second embodiment will be described, and the same components as those of the second embodiment will be assigned the same reference numerals and will not be described again. In this embodiment, the multiple comb-tooth patterns 75a to 75i may be collectively referred to as comb-tooth pattern 75.

[0131] The comb-tooth pattern 75 is formed by printing and hardening a low-resistance conductive paste, similar to the comb-tooth pattern 45. As shown in Fig. 14, the comb-tooth pattern 75 in this embodiment is provided between the resistor 40 and the wiring pattern 70. The comb-tooth pattern 75 in this embodiment corresponds to an example of the "second comb-tooth pattern" in the present invention.

[0132] 16, each of the comb-tooth patterns 75a to 75i has a linear planar shape, branches off from the second main body portion 71 of the wiring pattern 70, and extends along the Y direction in the figure. The comb-tooth patterns 75a to 75i protrude from the wiring pattern 70 toward the resistor 40. That is, the comb-tooth patterns 75a to 75i are connected to the wiring pattern 70 and extend below the sliding area SA. The multiple comb-tooth patterns 75a to 75i are arranged in parallel at substantially equal intervals.

[0133] 14, all of the comb-tooth patterns 45a to 45j and 75a to 75i face the connector 80 via the openings 91 of the spacer 90, and overlap with the sliding area SA of the slider 100 in a plan view. Also, as shown in FIGS. 14 to 16, the comb-tooth patterns 45a to 45j and the comb-tooth patterns 75a to 75i are arranged alternately and at substantially equal intervals along the X direction in a plan view.

[0134] The number of the comb tooth patterns 45, 75 is not particularly limited to the above. Furthermore, the arrangement of the comb tooth patterns 45, 75 is also not particularly limited to the above. Incidentally, as will be described later, the greater the number of the comb tooth patterns 45, 75, the higher the resolution of the output of the variable resistor 1C. Furthermore, as long as a gap is secured between the comb tooth patterns 45, 75, the gap between the comb tooth patterns 45, 75 is not limited to being equal.

[0135] In this embodiment, the first intervening portion 23 of the first resist layer 20 includes a portion filling the space between the comb tooth patterns 45, a portion filling the space between the comb tooth patterns 75, and a portion filling the space between the comb tooth patterns 45 and 75, and these portions are interconnected. Therefore, the planar shape of the first intervening portion 23 is a serpentine shape extending in the X direction.

[0136] Furthermore, the third intervening portion 25 has a portion filling the space between the second resist layer 50 and the comb-tooth patterns 45 a, 45 j, as well as a portion filling the space between the second resist layer 50 and the comb-tooth patterns 75 a, 75 i. Therefore, the planar shape of the third intervening portion 25 is L-shaped.

[0137] 14 and 15, when the slider 100 is pressed, the base material 61 of the upper membrane substrate 60B bends downward, and the connectors 80 come into contact with the adjacent comb-tooth patterns 45, 75. This electrically connects the resistor 40 and the wiring pattern 70 via the connectors 80. Specifically, in the state shown in FIG. 15, comb-tooth pattern 45f among comb-tooth patterns 45a to 45j and comb-tooth pattern 75e among comb-tooth patterns 75a to 75i are electrically connected via the connectors 80.

[0138] Note that there may be a plurality of comb-tooth patterns 45a to 45j that are simultaneously connected to the connecting body 80 by pressing the slider 100. Similarly, there may be a plurality of comb-tooth patterns 75a to 75j that are simultaneously connected to the connecting body 80 by pressing the slider 100.

[0139] In this embodiment, as the slider 100 slides while pressing against the upper membrane substrate 60B, the combination of the comb tooth patterns 45, 75 connected by the connector 80 changes sequentially, thereby varying the resistance length (resistance value) of the resistor 40.

[0140] 15 , as described above, the comb-tooth patterns 75e and 45f are connected via the connector 80. As the slider 100 slides in the +X direction in the figure from this state, the combination of comb-tooth patterns connected via the connector 80 changes as follows: comb-tooth patterns 75e and 45f → comb-tooth patterns 45f and 75f → comb-tooth patterns 75f and 45g → comb-tooth patterns 45g and 75g → comb-tooth patterns 75g and 45h → ... → comb-tooth patterns 45i and 75i → comb-tooth patterns 75i and 45j.

[0141] Accordingly, the wiring pattern 70 connected to the comb-tooth patterns 75a to 75i detects a voltage (detected voltage) corresponding to the combination of the comb-tooth patterns 45, 75 connected via the connector 80. That is, in this embodiment as well, the resistance value between the wiring patterns 31, 70 changes depending on the pressing position of the slider 100. When the slider 100 slides in the +X direction in the figure, the resistance value between the wiring patterns 31, 70 gradually increases as the slider 100 slides. A multimeter or the like is connected to the wiring patterns 31, 70 of this variable resistor 1C, and the multimeter or the like outputs the potential difference between the power supply voltage and the detected voltage of the wiring pattern 70.

[0142] 15, when the slider 100 slides in the −X direction in the figure, the combination of the comb-tooth patterns connected via the connector 80 changes as the slider 100 slides, from comb-tooth patterns 45f, 75e → comb-tooth patterns 75e, 45e → comb-tooth patterns 45e, 75d → comb-tooth patterns 75d, 45d → comb-tooth patterns 45d, 75c → ... → comb-tooth patterns 45b, 75a → comb-tooth patterns 75a, 45a. In this case, the resistance value between the wiring patterns 31 and 70 gradually decreases as the slider 100 slides.

[0143] In this third embodiment, the first intervening portion 23 fills the space between the comb tooth patterns 45, 75, so that deterioration of the comb tooth patterns 45, 75 can be suppressed as in the first embodiment, and deterioration of the detection accuracy of the variable resistor 1C can also be suppressed.

[0144] It should be noted that the above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, the elements disclosed in the above embodiments are intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0145] For example, in the first to third embodiments, the comb-tooth pattern 45 is formed on the lower membrane substrate 10 A, but it may be formed on the upper membrane substrate 60 A that is pressed by the slider 100 .

[0146] In the first to third embodiments, the variable resistors 1A to 1C are operated by the slider 100 provided in the variable resistors 1A to 1C themselves, but this is not limiting. For example, instead of the slider 100, the variable resistors may be operated by the operator's finger.

[0147] Furthermore, in the above-described embodiment, the resistance values ​​of the variable resistors 1A to 1C were detected by connecting the wiring pattern 31 to a power supply and the wiring pattern 35 to ground and acquiring the detected voltage of the wiring pattern 70, but the circuit configuration for detecting the resistance values ​​of the variable resistors is not particularly limited to this.

[0148] For example, the wiring pattern 35 may not be provided, and a power source may be connected to the wiring patterns 31 and 70. In this case as well, the resistance value between the wiring patterns 31 and 70 changes depending on the pressing position of the slider 100.

[0149] DESCRIPTION OF SYMBOLS 1A to 1C... variable resistor 10A to 10C... lower membrane substrate 11... base material 11a... upper surface 20... first resist layer 21... thin portion 21a... upper surface 22... protruding portion 22a... upper surface 23... first interposed portion 23a... first exposed portion 23b, 23c... first and second non-exposed portions 24... second interposed portion 25... third interposed portion 31... wiring pattern 35... wiring pattern 40... resistor 45, 45a to 45j... comb-tooth pattern 46... upper surface 47... lower surface 48a... second exposed portion 48b, 48c... third and fourth non-exposed portions 50... second resist layer 50a... upper surface 51... opening 60A, 60B... upper membrane substrate 61... base material 62...lower surface 63...upper surface 70...wiring pattern 71...second main body portion 711...parallel portion 72...second protective layer 75, 75a to 75i...comb-tooth pattern 76...second tip surface 80...connector 80a, 80b...edge portion 81...first main body portion 82...first protective layer 90...spacer 91...opening 100...slider 110...pressing portion 200...release film 201...film 202...release layer NA...non-overlapping area SA...sliding area

Claims

1. A first base material, a plurality of comb tooth patterns supported by the first base material and extending with a space therebetween, and an insulator disposed on the first base material so as to fill the space between the comb tooth patterns, wherein the comb tooth pattern has a tip surface on the side opposite to the first base material, and the tip surface is a variable resistor exposed from the insulator.

2. The variable resistor according to claim 1, wherein the insulator has a first main surface on the side opposite to the first base material, and the height of the tip surface from the first base material is substantially the same as the height of the first main surface from the first base material.

3. The variable resistor according to claim 1, wherein the insulator has a first main surface on the side opposite to the first base material, and the first main surface extends substantially parallel to the first base material.

4. The variable resistor according to claim 1, wherein the insulator includes a first intervening portion located between the comb tooth patterns, and a second intervening portion located between the first base material and the comb tooth patterns.

5. The variable resistor according to claim 1, wherein the insulator has a first main surface on the side opposite to the first base material, the variable resistor includes a resistor body, the plurality of comb tooth patterns include a plurality of first comb tooth patterns connected to the resistor body, the first comb tooth pattern includes a first portion whose tip surface is exposed from the insulator, and a second portion integrally formed with the first portion and connected to the resistor body, and in a first direction perpendicular to the first main surface, the thickness of the second portion is thinner than the thickness of the first portion.

6. The variable resistor according to claim 1, wherein the variable resistor includes a resistor body disposed on the first base material, a first wiring pattern disposed on the first base material and connected to the resistor body, a spacer having an opening, a second base material laminated on the first base material via the spacer, a connection body disposed on the second base material so as to be located within the opening and electrically connected to the resistor body by pressing of a slider from the outside of the second base material, and a second wiring pattern disposed on the second base material and connected to the connection body, or disposed on the first base material and electrically connected to the connection body by pressing of the slider. In a plan view, the connecting body has a non-overlapping region that does not overlap with the resistor body. In a plan view, the sliding region where the slider is slidable is included in the non-overlapping region. The front end face is the face facing the connecting body in the comb tooth pattern. A variable resistor in which the resistance value between the first wiring pattern and the second wiring pattern changes according to the position of the slider.

7. The variable resistor according to claim 6, wherein the second wiring pattern is disposed on the second base material and is connected to the connecting body. The plurality of comb tooth patterns includes a plurality of first comb tooth patterns connected to the resistor body. In a plan view, the first comb tooth pattern overlaps with the sliding region. The connecting body is a variable resistor that comes into contact with the first comb tooth pattern by pressing of the slider from the outside of the second base material.

8. The variable resistor according to claim 6, wherein the second wiring pattern is disposed on the first base material. The plurality of comb tooth patterns includes a plurality of first comb tooth patterns connected to the resistor body. In a plan view, the first comb tooth pattern and the second wiring pattern overlap with the sliding region. The connecting body is a variable resistor that comes into contact with the first comb tooth pattern and the second wiring pattern by pressing of the slider from the outside of the second base material.

9. The variable resistor according to claim 6, wherein the second wiring pattern is disposed on the first base material. The plurality of comb tooth patterns includes a plurality of first comb tooth patterns connected to the resistor body 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 alternately arranged along the extending direction of the connecting body in the sliding region. The connecting body is a variable resistor that comes into contact with the first and second comb tooth patterns by pressing of the slider from the outside of the second base material.

10. The variable resistor according to claim 6, wherein the variable resistor is disposed on the first base material and further includes a third wiring pattern connected to the resistor body. The plurality of comb tooth patterns includes a third comb tooth pattern connected to the first wiring pattern and a fourth comb pattern connected to the third wiring pattern; In a plan view, the third and fourth comb patterns are variable resistors overlapping the sliding region. **Claim 11** A method for manufacturing a variable resistor according to any one of claims 1 to 10, a first step of preparing a support having a release-treated surface; a second step of forming the comb pattern on the release-treated surface of the support; a third step of forming the insulator on the release-treated surface so as to fill between the comb patterns; a fourth step of transferring the comb pattern and the insulator from the support to the first base material. A method for manufacturing a variable resistor comprising the steps of.