JP2002050856A - Membrane circuit, its manufacturing method and mounting land forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane circuit, its manufacturing method and a mounting land forming method capable of preventing deterioration of insulation of an electrode and short-circuiting due to bleeding of a conductive adhesive. SOLUTION: An insulation film 1 is worked into a desired shape to print a wiring circuit 3 and electrodes 4a and 4b. The electrodes 4a and 4b are disposed at a prescribed interval. Next, a resist layer 2 being an insulation protecting layer is formed. The layer 2 has opening parts 2a and 2b so as to expose the parts of the electrodes 4a and 4b, and has isolated pattern parts 2c and 2d covering about half the respective tip sides of the electrodes 4a and 4b in these parts 2a and 2b. Grooves 6a and 6b are formed by the layer 2 and the parts 2c and 2d formed at the parts 2a and 2b. Next, the conductive adhesive 5 is printed, etc., so as to extend to the rear end parts of the electrodes 4a and 4b and the parts 2c and 2d to form mounting land parts 7a and 7b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane circuit used for a notebook personal computer, a mobile phone, and the like.
In particular, the present invention relates to a membrane circuit that prevents a printed circuit from being short-circuited due to crushing of a conductive adhesive or a conductive adhesive film at the time of component mounting, a method of manufacturing the same, and a method of forming a mounting land.

[0002]

2. Description of the Related Art Conventionally, when components such as a light emitting diode (LED), a quad flat package (QFP), and various connectors are mounted on a printed circuit composed of a polyethylene terephthalate (PET) substrate, instead of solder or the like. Conductive adhesive or anisotropic conductive material (ACF, ACP
Etc.) and mechanical pressure welding are used. That is, first,
Printing is performed on the printed circuit using a metal plate such as a conductive adhesive to form a mounting land portion. Next, components such as LEDs are installed on the formed mounting lands, and mounted on a printed circuit by a method such as mechanical crimping. After mounting by mechanical pressure bonding, the conductive adhesive is dried and cured (cured) in, for example, a hot-air drying furnace or the like, and a necessary portion is coated with a sealing resin. After that, the applied sealing resin is cured to complete the mounting of the component. In addition, the reason why the mounting land portion made of the conductive adhesive is formed on the printed circuit is to ensure the electrical conduction between the electrode of the component and the printed circuit, and after the conductive adhesive is cured, The reason why the sealing resin is applied is to sufficiently obtain the fixing force (mechanical strength) of the mounted component.

[0003]

However, in the mounting method as described above, for example, when the LED or the like is temporarily mounted using a conductive adhesive and then cured, the conductive adhesive formed with a printing metal plate is used. Between the mounting lands made of the agent, a circuit short-circuit or a phenomenon of a decrease in the insulation property that does not reach the circuit short-circuit may be observed. The decrease in the insulating property is considered to be caused by the spread of the conductive adhesive due to the collapse, and the main cause is attributed to the characteristics of the conductive adhesive itself.

For example, the most widely used conductive adhesives at present are epoxy-based or urethane-based non-solvent-based conductive adhesives (easier to mix resins) than solvent-based conductive adhesives. For paste stability, the solvent is 0.1%.
It may be contained in an amount of about 0.5 to 0.2 wt%. Among these non-solvent-based conductive adhesives, epoxy resin-based non-solvent-based conductive adhesives are most often used from the viewpoints of excellent adhesion strength and printing / workability.
In general, the epoxy resin-based solventless conductive adhesive (initial viscosity: 1000 to 2000 Pa · s) is used to extend the working life (pot life) when printing and to improve printability (so-called so-called “pot life”). To prevent liquid dripping)
A liquid epoxy component is used.

[0005] However, when a liquid epoxy component is used, a component having a low molecular weight (low molecular component) of the solventless conductive adhesive may precipitate on the surface of the adhesive and flow out when cured. Occasionally, a so-called bleeding phenomenon occurs in which the conductive particles (Ag filler) in the conductive adhesive also flow out together. The bleeding phenomenon frequently occurs when an LED, a C / R chip, or the like is mounted, and is caused by a capillary phenomenon in a gap between a mounting surface of a mounting component and an upper surface of a substrate. Hereinafter, the bleeding phenomenon will be described with reference to the drawings. FIG. 19 is a diagram illustrating a side surface including an upper surface and a partial cross section of the LED mounting unit 90. As shown in FIG.
The LED 91 is an Ag printed circuit 99 printed on the board 94.
Is mounted on the mounting land 98 formed on the electrode 92 of FIG. After that, the LED mounting portion 90 becomes the sealing resin 93
Is sealed and fixed. At this time, a broken line and FIG.
As shown by arrows in FIG. 5, the conductive adhesive forming the mounting land portion 98 may cause a bleeding phenomenon during curing after provisional mounting, and may flow out.

When the LED 91 is removed from the LED mounting portion 90 in which the bleeding phenomenon has occurred, as shown in FIG. 20, the conductive adhesive forming the mounting land portion 98 on the electrode 92 of the Ag printed circuit 99 causes the bleeding phenomenon. You can see how it changed. For example, as shown in FIG. 9A, when the conductive adhesive forming the mounting land portion 98 is printed on the electrode 92, the thickness of the conductive adhesive in the mounting direction is set to about 40 to 50 μm. In the case, the contour part 95 on which the LED 91 of the mounting land part 98 was mounted is used.
It can be seen that a small-scale bleeding phenomenon occurs at the position where the electrodes 92 face each other, and a bleeding region 96 is formed. Such a bleeding phenomenon does not lead to a short circuit, but has a problem that the insulating property between the electrodes 92 is significantly reduced.

Further, as shown in FIG. 1B, when the film thickness in the mounting direction of the conductive adhesive is set to about 65 to 90 μm, a large scale is formed at a position where the electrodes 92 of the contour 95 face each other. It can be seen that a bleeding phenomenon occurred, and the bleeding region 96 and the conduction path 97 due to the Ag filler flow were formed. In this bleeding phenomenon,
Since the electrodes 92 are electrically conducted through the Ag filler forming the conduction path 97, there is a problem that a circuit short-circuit occurs surely.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a membrane circuit, a method of manufacturing the same, and a method of forming a mounting land capable of preventing a reduction in electrode insulation performance and a short circuit due to bleeding of a conductive adhesive. The aim is to provide a method.

[0009]

According to the first and second membrane circuits of the present invention, a set of mounting lands is patterned on a substrate at a predetermined interval, and these patterns are formed on the set of mounting lands. A membrane circuit for mounting a mounting component with a conductive adhesive so as to straddle the mounting land, wherein at least two grooves for stopping the flow of the conductive adhesive are provided between the mounting land and the mounting land forming the set. It is characterized by being formed.

A resist layer having a predetermined thickness is formed on the substrate, the set of mounting lands is formed on the resist layer, and a groove between the mounting lands forming the set is formed by the resist. Preferably, the grooves are engraved in the layer.

The groove has a depth of 25 to 40 μm and a width of 5 μm.
It is desirable that the thickness be 15 μm.

Preferably, the groove between the mounting lands forming the set is a groove formed on the substrate between the mounting lands forming the set.

The groove is preferably formed by irradiating the substrate with a laser beam.

The groove preferably has a depth of 20 to 50 μm.
m, the width is 0.1 to 0.2 mm.

[0015] A third membrane circuit according to the present invention comprises:
A membrane circuit in which a plurality of mounting lands are arranged and formed on a substrate, and a mounting circuit is mounted on the mounting lands by using a conductive adhesive, wherein a flow of the conductive adhesive is stopped between the plurality of mounting lands. Characterized in that at least two grooves are formed.

A fourth membrane circuit according to the present invention comprises:
A set of mounting lands is patterned at predetermined intervals on a substrate, and a membrane circuit for mounting a mounting component by a conductive adhesive so as to straddle these mounting lands over the set of mounting lands, Each of the mounting lands forming a set is characterized in that the mounting lands are separated in a direction orthogonal to the facing direction of the mounting lands.

In the method of manufacturing a membrane circuit according to the present invention, a step of patterning a set of electrodes made of a conductive paste at predetermined intervals on a substrate, and the step of patterning the electrodes forming the set by the step. A resist layer is formed on the substrate, openings are respectively formed in the resist layer so that the electrodes of the set are exposed, and the resist layer covering each tip side of the electrodes of the set is formed in the opening. Forming an isolated pattern portion consisting of: a step of forming at least two grooves engraved in the resist layer between the electrode and the electrode forming the set, and including the isolated pattern portion formed by this step. Forming a set of mounting lands by applying a conductive adhesive to form a predetermined pattern on each electrode of the set; and forming the mounting lands by this step. Characterized by comprising a step of mounting the mounting component so as to extend over these mounting lands on the lands set.

In the method for forming a mounting land of a membrane circuit according to the present invention, a pattern of a set of electrodes made of a conductive paste at predetermined intervals is formed on a substrate, and the electrodes forming the set are patterned on the substrate. A resist layer is formed on the resist layer, and openings are formed in the resist layer so that the electrodes forming the set are exposed, and the isolated resist layer covering the front ends of the electrodes forming the set is formed in the openings. A pattern portion is formed, and a conductive adhesive is applied so as to form a predetermined pattern on each of the electrodes including the formed isolated pattern portion, thereby forming a set of mounting lands.

According to the first to third membrane circuits of the present invention, a set of mounting lands patterned on the substrate at predetermined intervals or a mounting land of a plurality of mounting lands arranged in an array. Since at least two grooves for stopping the flow of the conductive adhesive are formed between
When mounting components are mounted on these mounting lands with a conductive adhesive, even if conductive particles flow out (hereinafter referred to as "bleeding") due to the outflow of low molecular components of the conductive adhesive due to capillary action, Electrical conduction between the mounting lands can be prevented. Therefore, it is possible to prevent a short circuit of the membrane circuit and a decrease in insulation performance around the mounting land.

According to the fourth membrane circuit of the present invention, each of the mounting lands of the set of mounting lands patterned on the substrate at predetermined intervals is separated in a direction orthogonal to the opposing direction of both mounting lands. When mounting a mounted component with a conductive adhesive over the set of mounting lands, the amount of conductive adhesive crushed by the mounted components on the mounting land Can be reduced, the amount of conductive particles of the conductive adhesive flowing out by bleeding can be reduced, and electrical conduction between the mounting lands can be prevented. Therefore, it is possible to prevent a short circuit of the membrane circuit and a decrease in insulation performance around the mounting land.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart showing a manufacturing process of a membrane circuit according to a first embodiment of the present invention, FIG. 2 is a partial cross-sectional view of the manufactured membrane circuit, and FIG. 3 is a schematic top view of the manufactured membrane circuit. Figure,
FIG. 4 is a partial cross-sectional view when components are mounted on the membrane circuit of FIG. First, a sheet or the like constituting an insulating film 1 serving as a base of a membrane circuit made of polyethylene terephthalate (PET) or the like is processed into a desired shape (S1). Next, a wiring circuit 3 made of Ag or the like for forming a membrane circuit on the upper surface of the insulating film 1 and the electrodes 4a, 4
b is printed by a method such as screen printing (S2).
The electrodes 4a and 4b are arranged at predetermined intervals according to the electrode terminals of the mounted components mounted so as to straddle them.

Next, on the insulating film 1 on which the wiring circuit 3 and the electrodes 4a and 4b are formed, a resist layer 2 as an insulating protection layer is formed with a thickness of about 20 to 40 μm (S3).
As shown in FIG. 3, the resist layer 2 has openings 2a and 2b so that the electrodes 4a and 4b are exposed, and the front ends of the electrodes 4a and 4b are inserted into the openings 2a and 2b. It has isolated pattern portions 2c and 2d that cover about half. The isolated pattern portions 2c and 2d have trapezoidal planar shapes whose short sides are the distal ends, and the openings 2a and 2b have isolated planar portions 2a and 2b whose planar shapes are distal ends of the electrodes 4a and 4b.
Along the outer diameters of c and 2d, the rear end side has a shape with a predetermined curvature and a large gap surrounding the isolated pattern portions 2c and 2d. As a result, a groove 6 having a predetermined width, for example, about 5 to 15 μm, is provided between the openings 2a, 2b on the tip side of the electrodes 4a, 4b and the isolated pattern sections 2c, 2d.
a, 6b are formed. Such fine grooves 6a, 6b
In order to form the resist layer 2, it is desirable to use a so-called insulating protective material having a high thixotropy (less dripping or spreading) and form the resist layer 2 by a method such as screen printing.

Next, a conductive adhesive 5 is printed so as to extend over the rear ends of the electrodes 4a and 4b exposed to the openings 2a and 2b of the resist layer 2 and the isolated pattern portions 2c and 2d.
The mounting lands 7a and 7b are formed (S4). afterwards,
As shown in FIG. 4, the LED 8 of the mounted component is connected to the electrodes 4a, 4a.
b on the mounting lands 7a and 7b so as to straddle
The LED 8 is mounted on the electrodes 4a and 4b by a mounting device (not shown) such as a mounter (S5). At this time, LED
8 and the conductive adhesive 5 sandwiched between the resist layer 2
It is crushed and spreads out in a plane. Then, L
The conductive adhesive 5 printed in step S4 including the portion sandwiched between the ED 8 and the resist layer 2 is cured (dried and cured) (S6), and the LED 8 and the electrodes 4a and 4b are connected to the conductive adhesive 5 Fully electrically connected via Lastly, a sealing resin (not shown) is applied around the mounting portion of the LED 8 (S9), and the applied sealing resin is dried and cured (cured).
As a result, a membrane circuit is manufactured.

According to the membrane circuit of this embodiment, the resist pattern 2 formed between the electrodes 4a and 4b and the isolated pattern portions 2c and 2d formed in the openings 2a and 2b in step S3 of the manufacturing process are used. Grooves 6a and 6b are formed. For this reason, when the conductive adhesive 5 is cured in step S6, bleeding of the low-molecular component of the conductive adhesive 5 occurs, and even if the conductive particles flow out together, the low-molecular component that has flowed out due to the bleeding. And the conductive particles flow to the bottoms of the grooves 6a and 6b as indicated by arrows in FIG. The conductive particles flowing into the grooves 6a and 6b are
Until overcoming the resist layer 2 between a and 6b
There is no direct connection. Thereby, the electrodes 4a, 4b
Are not electrically conducted, so that a short circuit of the membrane circuit due to bleeding can be prevented. Even if bleeding occurs, the low molecular components and conductive particles of the conductive adhesive 5 can flow out of the mounting lands 7a and 7b only onto the insulating film 1 on which the resist layer 2 is not formed. Therefore, it does not flow out in an unlimited range, and it is possible to suppress a decrease in insulation performance around the electrodes 4a and 4b. The low molecular components and the conductive particles that have entered the grooves 6a and 6b are separated from the isolated pattern portion 2 along the inner walls of the openings 2a and 2b.
It is guided to the rear side of c and 2d.

Next, a second embodiment of the present invention will be described. FIG. 5 is a flowchart showing a process of manufacturing a membrane circuit according to a second embodiment of the present invention, FIG. 6 is a partial cross-sectional view of the manufactured membrane circuit, and FIG. FIG. 8 is a cross-sectional view showing how bleeding of the conductive adhesive occurs, and FIG. 8 is a partial cross-sectional view when components are mounted on the membrane circuit of FIG. First, a sheet or the like constituting the insulating film 10 made of PET or the like is processed into a desired shape (S10). Next, the wiring circuit 12 made of Ag or the like and the first electrode 13a,
13b is printed by a method such as screen printing (S1).
1). As in the case of the above-described manufacturing process step S2,
The electrodes 13a and 13b are arranged at predetermined intervals in accordance with the electrode terminals of the mounted components mounted so as to straddle them.

Next, the wiring circuit 12 and the electrodes 13a, 13
A resist layer 11 is formed on the insulating film 10 on which the b is formed with a thickness of about 20 to 40 μm as in step S3 (S12). Since the formed resist layer 11 has the same configuration as the above-described resist layer 2, the description is omitted here. By the processing in step S12, the same grooves 15a, 15b as the grooves 6a, 6b as described above.
b is formed.

Next, the openings 11a, 1a of the resist layer 11 are formed.
The second electrodes 16a and 16b are formed by screen printing or the like so as to extend over the rear ends of the first electrodes 13a and 13b exposed to 1b and the isolated pattern portions 11c and 11d (S13). Then, the conductive adhesive 14 is printed so as to extend over the tip portions of the formed second electrodes 16a and 16b and the isolated pattern portions 11c and 11d to form the mounting lands 17a and 17b (S14). . After that, as shown in FIG.
It is mounted on the mounting lands 17a and 17b so as to straddle the wiring 13b and mounted by a mounting device or the like (S15). At this time, the conductive adhesive 14 sandwiched between the LED 18 and the resist layer 11 is crushed and spreads two-dimensionally. In the subsequent step, the conductive adhesive 14 printed in step S14 is cured (S16), and the LED 18 and the first electrode 13 are cured.
a and 13b are electrically connected. Finally, a sealing resin is applied (S17), and the applied sealing resin is cured (S18) to complete the membrane circuit.

According to the membrane circuit of this embodiment, the resist layer 11 and the openings 11a and 11b formed between the first electrodes 13a and 13b and the second electrodes 16a and 16b in the step S12 of the manufacturing process are used. Grooves 15a and 15b are formed by the formed isolated pattern portions 11c and 11d. For this reason, in step S16, the conductive adhesive 1
Even when bleeding of the low molecular components of the conductive adhesive 14 containing the conductive particles occurs when curing 4, these flow into the grooves 15 a and 15 b as shown by arrows in FIG. 8. Therefore, the first and second electrodes 13a, 13b, 16
Since a and 16b are not electrically conducted, short circuit of the membrane circuit can be prevented. Even if bleeding occurs, bleeding of the conductive adhesive 14 from the mounting lands 17a and 17b occurs only on the insulating film 1 on which the resist layer 11 is not formed, so that the range of bleeding is limited. And the first and second electrodes 13a, 13a
It is possible to prevent the insulation performance from decreasing around the b, 16a, and 16b.

For example, as shown in FIG. 7, in a commonly used printing process of the conductive adhesive 84, the insulating film 80 is used.
After the Ag wiring circuit 82 and the electrodes 83a and 83b are formed thereon, a printing metal plate 19, which is a stainless steel plate having a thickness of 0.07 to 0.1 mm, is covered as a mask, and for example, the applied conductive adhesive 84 is applied. Printing is performed by squeegee 20 in the direction indicated by the arrow. At this time, if there is a deformed portion 19a in the printing metal plate 19, the conductive adhesive 84
May bleed in the direction of the arrow, resulting in a short circuit. For example, in step S13,
The second electrodes 16a and 16b are connected to the isolated pattern portions 11c and 11d after the formation of the resist layer 11 and the first electrodes 13a and 13b.
b, the mounting land portion 17 made of the conductive adhesive 14 in step S14.
a, 17b is formed in the substantially isolated pattern portion 11
Only the process of forming the mounting lands 17a and 17b on c and 11d is sufficient, and it is possible to form (fine) mounting lands having high printing resolution.

Next, a third embodiment of the present invention will be described. FIG. 9 is a flowchart showing a manufacturing process of the membrane circuit according to the third embodiment of the present invention, and FIG.
FIG. 11 is a schematic cross-sectional view taken along the line AA ′ of FIG. 10, FIG. 12 is a perspective view showing a part of a manufacturing process of the membrane circuit, and FIG. 13 is a membrane diagram of FIG. FIG. 3 is a partial cross-sectional view when components are mounted on a circuit. First, as in the first and second embodiments described above, P
A sheet or the like constituting the insulating film 21 such as ET is processed into a desired shape (S20). Next, a wiring circuit 23 made of Ag or the like and electrodes 24a, 24
b is printed by a method such as screen printing (S2
1). After the electrodes 24a and 24b are formed, for example, FIG.
As shown in FIG. 5, a pair of electrodes 24a and 24b formed in step S21 is formed by using a laser irradiation device (not shown) for irradiating a CO ₂ laser from a laser irradiator tip 26.
Wavy grooves 27a and 27b are engraved and formed in the insulating film 21 therebetween (S22). As shown in FIG. 10, the fan-shaped liquid reservoirs 27c and 27d formed at one end in the longitudinal direction of the grooves 27a and 27b cause a large amount of low molecular components of the conductive adhesive 22 to flow out due to bleeding. And
This is provided to store the gas when it flows into the grooves 27a and 27b. When the grooves 27a and 27b are formed, the insulating film 2 between the electrodes 24a and 24b may be used.
The portion formed in 1 may be formed linearly, but based on the research results of the present inventor, forming it in a wavy shape can effectively reduce the bleeding force of the conductive adhesive 22. Since it is possible to construct a more reliable short-circuit prevention structure, the wavy grooves 27a and 27b
Has been adopted. Note that the depth of the grooves 27a and 27b is desirably about 20 to 50 μm. This is because if the depth is as large as this, the low molecular component of the bleeding conductive adhesive can be sufficiently stored.

Next, at step S22, the grooves 27a, 27b
Is formed, the conductive adhesive 22 is applied to the electrodes 24a and 24a.
b at a predetermined position on the mounting lands 28a, 28
b is formed (S23). Thereafter, the mounted component is placed on the mounting lands 28a and 28b formed in step S23, mounted by a mounting device (S24), and includes a portion sandwiched between the mounted component and the electrodes 24a and 24b. The conductive adhesive 22 printed in step S23 is cured (S23).
25) Then, a sealing resin is further applied (S26), and the applied sealing resin is cured (S27) to complete the membrane circuit.

According to the membrane circuit of this embodiment, the electrodes 24 are formed by laser processing in step S22 of the manufacturing process.
a, 24b in the insulating film 21 between the wavy grooves 27a, 2b.
7b is engraved. Therefore, when the conductive adhesive 22 is cured in step S25, bleeding as described above occurs, and even if the low-molecular component and the conductive particles flow out,
As shown by arrows in FIG. 13, these low molecular components and conductive particles flow to the bottoms of the grooves 27a and 27b. Grooves 27a, 2
Since the conductive particles flowing into the inside 7b are not directly connected until they get over the insulating film 21a between the grooves 27a and 27b, the electrodes 24a and 24b do not conduct electrically. Therefore, short circuit of the membrane circuit due to bleeding can be prevented. In addition, even if bleeding occurs, the low molecular components and the conductive particles of the conductive adhesive 22 flow into the grooves 27a and 27b, and even if the amount of the flowing is large, a liquid reservoir formed by being connected to the grooves 27a and 27b. The electrodes 24a, 24 are stored in the portions 27c, 27d.
It is possible to suppress a decrease in the electrical insulation performance around b. In addition, a groove is formed by laser processing in this way,
The idea of preventing a short circuit or the like due to bleeding can be used even in the case shown in FIG. That is, for example, a plurality of adjacent electrodes 85a to 85c
The mounting component 87 is placed on the upper surface via conductive adhesives 88a to 88c.
When the connection terminals 86a to 86c are mounted, the substrate 1 around the electrodes 85a to 85c (in particular, between adjacent electrodes)
By forming the groove 89 on the surface of the metal layer 00, it is possible to suppress a short circuit and a decrease in electrical insulation performance.

Next, a mounting land portion according to an embodiment of the present invention will be described. FIG. 15 is a schematic diagram showing a conventional mounting land portion, FIGS. 16 and 17 are schematic diagrams showing a mounting land portion according to an embodiment of the present invention, and FIG. 18 is another mounting land portion of the present invention. FIG. FIG.
As shown in (a), the conventional mounting lands 30a, 30
“b” is formed by applying a conductive adhesive 32 to predetermined positions on the pair of electrodes 31a and 31b, for example.
The shape of the mounting lands 30a and 30b is
a and 31b are formed in a predetermined solid pattern in a direction orthogonal to the facing direction. When the mounting lands 30a and 30b having such a shape are formed, as shown in FIG.
In this case, the mounting lands 30a and 30b are significantly crushed, and the conductive adhesive 3 that has flowed out due to the occurrence of bleeding.
In many cases, the conductive path 34 is formed by the second conductive particles, which indicates that a short circuit is likely to occur. On the other hand, FIG.
As shown in FIG. 6 (a), the inventor of the present invention forms a plurality of mounting lands 40a to 40d on the respective electrodes 41a and 41b without using the conventional mounting lands 30a and 30b. The land part was constructed and the device was designed to mount the mounted components. That is, the pair of electrodes 41a and 41b
That is, the mounting lands 40a to 40d of the pattern separated in the direction orthogonal to the facing direction are formed. These mounting lands 40a to 40d are formed by separating the conductive adhesive 42 in a direction orthogonal to the opposing direction on the electrodes 41a and 41b and applying a pattern to the conductive land 42a in a circular shape.
It is formed so as to remove as much as possible the portion crushed by the mounted components from the conventional mounting lands 30a and 30b (indicated by broken lines). For this reason, as shown in FIG. 3B, even in the mounting portion 43 after mounting the mounting components, for example, a remarkable crush as seen in the conventional mounting lands 30a and 30b occurs on the mounting lands 40a to 40d. Even if bleeding occurs, the amount of the low-molecular component and the conductive particles of the conductive adhesive 42 which flowed out becomes much smaller even if bleeding occurs. Therefore, it is difficult for a conductive path to be formed between the electrodes 41a and 41b. A mounting land in which a short circuit hardly occurs can be realized. In addition, since a plurality of mounting lands 40a to 40d are formed on the respective electrodes 41a and 41b, electrical continuity with the mounted components can be sufficiently ensured similarly to the conventional mounting lands 30a and 30b, which is extremely practical. It can be said that it is a target.

For example, a so-called 1608 size (horizontal 1.
60, 0.80 mm in height), the mounting lands 40 a to
40d may be formed. In order to mount the mounting component 51 of a so-called 1005 size (horizontal 1.00, vertical 0.50 mm), each mounting land 50 having dimensions as shown in FIG.
a to 50d may be formed. 17 and 18
The dimensions shown in FIG. 3 are merely a guide that, when the mounting lands are formed in accordance with such dimensions, a short circuit between the electrodes forming the set can be easily prevented. Also, the mounting lands 40a to 40d shown in FIG. 17 may be formed in a circular shape, or the mounting lands 50a to 50d shown in FIG.
Each corner of 50d is formed with a bend of about R0.1 mm because the resolution (precision) of printing at the time of forming the mounting land can be improved. In this embodiment, a conductive adhesive is used as a material for forming the mounting land. However, for example, cream solder can be used. When cream solder is used, if the mounting lands are formed as shown in FIGS. 17 and 18, the total amount of cream solder applied (total printing amount) can be suppressed, and the so-called chip standing phenomenon can be suppressed. It is possible.

As described above, according to the present embodiment, a plurality of mounting lands are formed on the electrodes in a shape in which the conductive adhesive in the mounted and crushed portion, which is the conventional mounting land portion, is almost removed. Therefore, the outflow of the low molecular components and the conductive particles due to the bleeding of the conductive adhesive when the mounted component is actually mounted can be largely suppressed. As a result, even if bleeding occurs, the low-molecular components and the conductive particles flowing out between the mounting lands (for example, 50a and 50b) on the same electrode may be connected. In addition, since a bleeding low molecular component or the like does not reach between adjacent electrodes, a circuit short circuit does not occur. Therefore, it is possible to prevent a short circuit of the membrane circuit and to suppress a decrease in insulation performance around the electrodes.

[0036]

As described above, according to the first to third membrane circuits of the present invention, a set of mounting lands patterned on a substrate at predetermined intervals or a plurality of lands formed in an array is formed. Since at least two grooves for stopping the flow of the conductive adhesive are formed between the mounting lands of the mounting lands and the mounting lands, when mounting components are mounted on these mounting lands by the conductive adhesive, Bleeding of low molecular components of the conductive adhesive by capillary action occurs,
Even if the conductive particles flow out, it is possible to prevent the electrical connection between the mounting lands, and it is possible to prevent a short circuit of the membrane circuit and a decrease in insulation performance around the mounting lands. .

According to the fourth membrane circuit of the present invention, each of the mounting lands of the set of mounting lands patterned on the substrate at predetermined intervals is separated in the direction orthogonal to the facing direction of both mounting lands. When mounting a mounted component with a conductive adhesive over the set of mounting lands, the amount of conductive adhesive crushed by the mounted components on the mounting land Can be reduced, the amount of the conductive particles of the conductive adhesive flowing out due to bleeding can be reduced, and the mounting lands can be prevented from being electrically connected to each other. There is an effect that it is possible to prevent a decrease in insulation performance around the mounting land.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a manufacturing process of a membrane circuit according to one embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of the manufactured membrane circuit.

FIG. 3 is a schematic top view of the manufactured membrane circuit.

FIG. 4 is a partial cross-sectional view when components are mounted on the manufactured membrane circuit.

FIG. 5 is a flowchart showing a manufacturing process of a membrane circuit according to a second embodiment of the present invention.

FIG. 6 is a partial cross-sectional view of the manufactured membrane circuit.

FIG. 7 is a cross-sectional view showing the appearance of bleeding of a conductive adhesive due to deformation of a printing metal plate.

FIG. 8 is a partial cross-sectional view when parts are mounted on the manufactured membrane circuit.

FIG. 9 is a flowchart showing a manufacturing process of a membrane circuit according to a third embodiment of the present invention.

FIG. 10 is a schematic top view of the manufactured membrane circuit.

11 is a sectional view taken along the line AA ′ of FIG.

FIG. 12 is a perspective view showing a part of the manufacturing process of the membrane circuit.

FIG. 13 is a partial cross-sectional view when components are mounted on the manufactured membrane circuit.

FIG. 14 is a schematic view when components are mounted on another manufactured membrane circuit.

FIG. 15 is a schematic view showing a conventional mounting land portion.

FIG. 16 is a schematic view showing a mounting land according to an embodiment of the present invention.

FIG. 17 is a schematic diagram showing the mounting land portion.

FIG. 18 is a schematic diagram showing another mounting land portion.

FIG. 19 is a diagram illustrating a side surface including an upper surface and a partial cross section of the LED mounting unit.

FIG. 20 is a diagram illustrating a state where an LED is removed from an LED mounting unit.

[Explanation of symbols]

1, 10, 21: insulating film, 2, 11: resist layer, 3, 12, 23: wiring circuit, 4, 13, 16, 2
4, 41, 85 ... electrodes, 5, 14, 22, 32, 42,
88: conductive adhesive, 6, 15, 27 ... groove, 7, 17,
28, 30: mounting land, 8, 18: LED, 19 ...
Metal plate for printing, 26: tip of laser irradiator, 34: conduction path, 40, 50: mounting land.

Claims (10)

[Claims] 1. A membrane circuit in which a set of mounting lands is patterned on a substrate at predetermined intervals and a mounting component is mounted on the set of mounting lands by a conductive adhesive so as to straddle these mounting lands. A membrane circuit, wherein at least two grooves for stopping the flow of the conductive adhesive are formed between the mounting lands forming the pair. 2. A resist layer having a predetermined thickness is formed on the substrate, the set of mounting lands is formed on the resist layer, and a groove between the set of mounting lands is 2. The membrane circuit according to claim 1, wherein the groove is a groove carved in the resist layer. 3. The membrane circuit according to claim 2, wherein said groove has a depth of 25 to 40 μm and a width of 5 to 15 μm. 4. The groove between the pair of mounting lands and the mounting land is a groove formed on the substrate between the pair of mounting lands. 2. The membrane circuit according to 1. 5. The membrane circuit according to claim 4, wherein said groove is formed by irradiating said substrate with laser light. 6. The membrane circuit according to claim 4, wherein the groove has a depth of 20 to 50 μm and a width of 0.1 to 0.2 mm. 7. A membrane circuit in which a plurality of mounting lands are arranged and formed on a substrate, and a mounting component is mounted on the mounting lands by a conductive adhesive, wherein the conductive bonding is provided between the plurality of mounting lands. A membrane circuit having at least two grooves for stopping a flow of an agent. 8. A membrane circuit in which a set of mounting lands is patterned on a substrate at a predetermined interval, and a mounting component is mounted on the set of mounting lands with a conductive adhesive so as to straddle these mounting lands. A membrane circuit, wherein each of the mounting lands forming the set has a pattern separated in a direction orthogonal to a facing direction of both mounting lands. 9. A step of patterning a set of electrodes made of a conductive paste at predetermined intervals on a substrate, and forming a resist layer on the substrate on which the electrodes of the set are patterned by this step. Along with each other, an opening is formed so that the electrode of the set is exposed in the resist layer, and an isolated pattern portion of the resist layer is formed in the opening to cover each tip side of the electrode of the set. Forming at least two grooves engraved in the resist layer between the electrodes forming the set and the electrodes; and forming a predetermined pattern on each of the electrodes forming the set including the isolated pattern portion formed by this step. Forming a set of mounting lands by applying a conductive adhesive to form a pattern; and mounting these mounting lands on the set of mounting lands formed by this step. Mounting a mounting component so as to extend. 10. A pattern of a set of electrodes made of a conductive paste at a predetermined interval is formed on a substrate, and a resist layer is formed on the substrate on which the electrodes forming the set are patterned. An opening is formed so that the electrodes forming the set are exposed, and an isolated pattern portion made of the resist layer covering each tip side of the electrodes forming the set is formed in the opening, and the formed isolated pattern is formed. A method for forming mounting lands for a membrane circuit, comprising forming a set of mounting lands by applying a conductive adhesive to form a predetermined pattern on each of the electrodes including a pattern portion.