JP7274377B2 - multilayer circuit board - Google Patents

Description

The present invention relates to a multilayer circuit board used for music players, home electric appliances, air conditioners, portable equipment, computer equipment, information communication equipment, equipment mounted on automobiles, and the like.

Capacitive sensors, which are multi-layered circuit boards that contribute to design and operability, are used in car navigation systems. a transparent base layer 1, a conductive X circuit pattern layer 3 laminated on this base layer 1, an insulating layer 4 laminated on this conductive X circuit pattern layer 3, and a conductive Y laminated on this insulating layer 4 A circuit pattern layer 7 is provided in a laminated structure, and three-dimensionally formed according to the shape and configuration of the car navigation system (see Patent Documents 1, 2, 3, 4, and 5).

The conductive X circuit pattern layer 3 and the conductive Y circuit pattern layer 7 are printed with a silver ink or the like to a thickness of about 5 μm to 15 μm, respectively, and part of thin conductive lines and the like overlap with the insulating layer 4 interposed therebetween. Both are connected to a capacitance detection circuit (not shown). In addition, in order to ensure reliable insulation, the insulating layer 4 consists of a first insulating layer 5 laminated on the conductive X circuit pattern layer 3, and a first insulating layer 5 and a conductive Y circuit pattern layer 7. It is divided into a second insulating layer 6 interposed therebetween, and the first and second insulating layers 5 and 6 are imparted with light transmittance, respectively.

When such a capacitance sensor is manufactured in a manufacturing process, it is transferred from the manufacturing process to an inspection process. In this inspection process, it is visually inspected and sorted into non-defective products and defective products, and then the non-defective products are shipped. be.

JP-A-60-120594 Japanese Patent No. 6360793 JP-A-06-350210 Japanese Patent Application Laid-Open No. 2017-215960 JP 2017-157184 A

The capacitance sensor, which is a conventional multi-layered circuit board, is constructed as described above. There is a problem that the pattern layer 3 and the conductive Y circuit pattern layer 7 are hardly shaded, and it is difficult to accurately distinguish between the conductive X circuit pattern layer 3 and the conductive Y circuit pattern layer 7 .

For example, when the insulating layer 4 is translucent and colorless, when the capacitance sensor is optically inspected from the back side, the conductive X circuit pattern layer 3 is located on the back side of the insulating layer 4, so the conductive layer 4 is located on the back side. Even if the X-circuit pattern layer 3 can be roughly grasped, it is not always easy to clearly grasp the conductive Y-circuit pattern layer 7 (see FIG. 6). Conversely, when the capacitive sensor is optically inspected from its surface, the conductive Y circuit pattern layer 7 is located closer to the surface than the insulating layer 4, so it is almost impossible to identify the conductive Y circuit pattern layer 7. Even if possible, it is difficult to identify the conductive X-circuit pattern layer 3 (see FIG. 7). Furthermore, it is extremely difficult to determine the positions of the conductive X circuit pattern layer 3 and the conductive Y circuit pattern layer 7 in the XY direction with high accuracy.

The present invention has been devised in view of the above, and it is possible to easily determine the relative positional relationship between the first and second conductive circuit pattern layers, and when inspecting from both sides, the first and second conductive circuit pattern layers can be easily determined. SUMMARY OF THE INVENTION It is an object of the present invention to provide a multilayer circuit board in which conductive circuit pattern layers can be easily identified.

In order to solve the above problems in the present invention, a first conductive circuit pattern layer, a light-transmitting insulating layer laminated on the first conductive circuit pattern layer, and a second conductive circuit pattern layer laminated on the insulating layer part of the first and second conductive circuit pattern layers overlap through an insulating layer, the insulating layer is colored for inspection, and the insulating layer is transparent to all light rays It is characterized by having a rate of 86% or less and a haze value of 9% or more .

In addition, it is preferable to include a flexible light-transmitting base layer and a light-transmitting lamination insulating layer interposed between the base layer and the first conductive circuit pattern layer.
It can also include a light transmissive insulating protective layer laminated on the second conductive circuit pattern layer.

The insulating layer includes a first insulating layer laminated on the first conductive circuit pattern layer and a second insulating layer interposed between the first insulating layer and the second conductive circuit pattern layer. and to impart light transmittance to these first and second insulating layers, and at least the first insulating layer of the first and second insulating layers can be colored for inspection.

Here, a part of the first and second conductive circuit pattern layers in the scope of claims includes at least a part, a half, and a major part of the overlap. Also, the coloring for inspection may be various colored (eg, green, red, etc.) or may be non-colored (eg, cloudy white) as long as it facilitates visual recognition. The total light transmittance of the insulating layer is preferably 86% or less, preferably 85% or less, more preferably 80% or less. Further, the multi-layer circuit board according to the present invention may be the capacitance sensor itself, or may be a versatile printed wiring board or the like, and it does not matter whether or not it can be formed three-dimensionally based on bending or the like.

According to the present invention, since the insulating layer that serves as the background of the first and second conductive circuit pattern layers is colored, there is no difference in brightness or saturation between the first and second conductive circuit pattern layers and the insulating layer. becomes larger, and it is possible to accurately distinguish between the first conductive circuit pattern layer and the second conductive circuit pattern layer.

According to the present invention, since the insulating layer is colored for inspection, the relative positional relationship between the first and second conductive circuit pattern layers can be easily determined. There is an effect that the first and second conductive circuit pattern layers can be easily identified. In addition, since the insulating layer has a total light transmittance of 86% or less and a haze value of 9% or more, it is possible to suppress the light transmittance of the insulating layer and prevent the overheating of the first and second conductive circuit pattern layers. The wrapped part can be grasped visually.

According to the second aspect of the invention, since the base layer has flexibility, three-dimensional formation of the multilayer circuit board is facilitated. In addition, since the laminated insulating layer is interposed between the base layer and the first conductive circuit pattern layer, the insulation between them is ensured regardless of the thickness of the base layer and the first conductive circuit pattern layer. be able to.
According to the third aspect of the invention, it is possible to cover and protect the second conductive circuit pattern layer from external dust and the like while ensuring the visibility of the second conductive circuit pattern layer from the insulating protective layer side. .

According to the fourth aspect of the invention, the insulating layer is not of a single layer structure but of a laminated structure consisting of the first and second insulating layers. It becomes possible to form freely and easily. Moreover, it is possible to prevent insufficient insulation between the first and second conductive circuit pattern layers.

BRIEF DESCRIPTION OF THE DRAWINGS It is cross-sectional explanatory drawing which shows typically the embodiment of the multilayer circuit board which concerns on this invention. FIG. 4 is a plan explanatory view when the capacitive sensor according to the present invention is optically inspected from the back side; FIG. 4 is a plan explanatory view when the capacitive sensor according to the present invention is optically inspected from the surface side; It is a cross-sectional explanatory view showing a conventional capacitive sensor. FIG. 10 is an explanatory plan view showing a conductive X-circuit pattern layer and a conductive Y-circuit pattern layer from which a part such as the central portion of a conventional capacitance sensor is omitted; FIG. 11 is a plan explanatory view when a conventional capacitive sensor is optically inspected from the back side; FIG. 10 is a plan explanatory view when a conventional capacitive sensor is optically inspected from the surface side;

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a conductive X-circuit pattern layer 3 laminated on the laminated insulating layer 2, and a light-transmitting insulating layer laminated on the conductive X-circuit pattern layer 3. 4, a conductive Y circuit pattern layer 7 laminated on the insulating layer 4, and a transparent insulating protective layer 8 laminated on the conductive Y circuit pattern layer 7 in a multi-layer structure, and the conductive X circuit pattern The layer 3 and the conductive Y circuit pattern layer 7 are partly overlapped with an insulating layer 4 interposed between them to form a three-dimensional capacitive sensor, and the insulating layer 4 is colored for inspection.

The base layer 1 is made of a predetermined resin film and is formed in a planar rectangular shape, convex shape, or the like. The resin film of the base layer 1 is not particularly limited, but examples thereof include polyester, polypropylene, polyethylene, polyethylene terephthalate, polycarbonate, polyamide, phenol resin, and acrylic resin films. Among these, an inexpensive, substantially colorless and transparent polyethylene terephthalate resin film, which is excellent in heat resistance, dimensional stability and insulation, is most suitable. The thickness of the base layer 1 is preferably 25 μm or more and 75 μm or less, preferably 40 μm or more and 60 μm or less, and more preferably about 50 μm, from the viewpoint of workability, handleability, and the like.

The laminated insulating layer 2 is formed into a substantially colorless and transparent thin film by printing a predetermined insulating resin on the surface of the base layer 1 by screen printing or the like and curing the resin. The insulating resin for the laminated insulating layer 2 is not particularly limited, but may be an ultraviolet curable insulating resin, a thermosetting insulating resin, a visible light curable insulating resin, an electron beam curable insulating resin, or a thermosetting insulating resin. and insulating resins. Among these resins, an ultraviolet curable insulating resin, more specifically an ultraviolet curable acrylic insulating resin, is most suitable because it has a small heat shrinkage when cured and contributes to energy saving. The thickness of the laminated insulating layer 2 is preferably 10 μm or more and 20 μm or less, preferably 12 μm or more and 18 μm or less, more preferably about 15 μm, in consideration of insulation properties, manufacturing cost, and the like.

The conductive X circuit pattern layer 3 is formed by printing a predetermined conductive material on the surface of the laminated insulating layer 2 by screen printing or the like, and drying and curing the printed material. The conductive material for the conductive X circuit pattern layer 3 is not particularly limited, but thermosetting resin-based silver ink, silver paste, etc., which are excellent in resistance stability and bendability, are suitable. The thickness of the conductive X circuit pattern layer 3 is preferably 5 μm to 15 μm, preferably 7 μm to 13 μm, more preferably 10 μm to 12 μm, from the viewpoint of thinning the multilayer circuit board.

The conductive X-circuit pattern layer 3 includes, for example, a plurality of X-direction detection electrodes arranged in the X-direction of the base layer 1 to detect capacitance, and a plurality of conductive lines connected to the plurality of X-direction detection electrodes. and A portion of the plurality of conductive lines overlaps the conductive Y circuit pattern layer 7 with the insulating layer 4 interposed therebetween. Each conductive line is printed as an elongated filament with a width of, for example, 0.05 mm, and extends from the end of the X-direction detection electrode to the peripheral edge of the base layer 1, and the free end is connected to a capacitance detection circuit (not shown). electrically connected.

The insulating layer 4 is laminated between the first insulating layer 5 laminated on the surface of the conductive X circuit pattern layer 3 and the conductive Y circuit pattern layer 7 interposed between the surface of the first insulating layer 5 and the conductive Y circuit pattern layer 7. and a second insulating layer 6 having a two-layer structure, and these first and second insulating layers 5 and 6 are imparted with light transmittance, in other words, transparency. The insulating layer 4 is formed by stacking two thick layers in order to ensure insulation between the conductive X circuit pattern layer 3 and the conductive Y circuit pattern layer 7 .

The first insulating layer 5 is formed into a transparent thin film by printing a predetermined insulating resin on the surface of the conductive circuit pattern layer by screen printing or the like and curing the resin. The insulating resin of the first insulating layer 5 is not particularly limited, but is an ultraviolet curable insulating resin, a thermosetting insulating resin, a visible light curable insulating resin, an electron beam A curable insulating resin and the like can be mentioned. Among these, an ultraviolet curable insulating resin, more specifically an ultraviolet curable acrylic insulating resin, is preferable because it has a small heat shrinkage when cured and contributes to energy conservation. The thickness of the first insulating layer 5 is preferably 10 μm or more and 20 μm or less, preferably 12 μm or more and 18 μm or less, more preferably about 15 μm, from the viewpoint of ensuring insulation and reducing manufacturing costs.

As with the first insulating layer 5, the second insulating layer 6 is formed by printing a predetermined insulating resin on the surface of the first insulating layer 5 by screen printing or the like, and hardening it into a substantially colorless and transparent thin film. It is formed. As with the first insulating layer 5, the insulating resin of the second insulating layer 6 may be an ultraviolet curable insulating resin, a thermosetting insulating resin, a visible light curable insulating resin, or an electron beam curable resin. A mold insulating resin or the like is selected.

Among these resins, UV-curing insulating resins, more specifically UV-curing acrylic insulating resins, are most suitable because of their small heat shrinkage during curing and excellent energy saving properties. As with the first insulating layer 5, the thickness of the second insulating layer 6 is optimally 10 μm or more and 20 μm or less, preferably 12 μm or more and 18 μm or less, more preferably about 15 μm.

As with the conductive X circuit pattern layer 3, the conductive Y circuit pattern layer 7 is formed by printing a predetermined conductive material on the surface of the second insulating layer 6 by screen printing or the like and drying and curing. The conductive material of the conductive Y circuit pattern layer 7 is not particularly limited, but a thermosetting resin-based silver ink, silver paste, or the like, which is excellent in resistance stability and bendability, is employed. The thickness of the conductive Y circuit pattern layer 7 is preferably 5 μm to 15 μm, preferably 7 μm to 13 μm, more preferably 10 μm to 12 μm, from the viewpoint of thinning the multilayer circuit board.

The conductive Y-circuit pattern layer 7 includes, for example, a plurality of Y-direction detection electrodes arranged in the Y-direction of the base layer 1 to detect capacitance, and a plurality of conductive lines connected to the plurality of Y-direction detection electrodes. and Some of the plurality of conductive lines overlap the conductive lines of the conductive X circuit pattern layer 3 and the like with the insulating layer 4 interposed therebetween. Each conductive line is printed as an elongated filament with a width of 0.05 mm, for example, and extends from the end of the Y-direction detection electrode to the peripheral edge of the base layer 1, and the free end is connected to a capacitance detection circuit (not shown). electrically connected.

The insulating protective layer 8 is a substantially colorless transparent film that covers and protects the conductive Y circuit pattern layer 7 by printing a predetermined insulating resin on the surface of the conductive Y circuit pattern layer 7 by screen printing or the like and curing the resin. It is formed. The insulating resin for the insulating protective layer 8 is not particularly limited, but may be ultraviolet curable insulating resin, thermosetting insulating resin, visible light curable insulating resin, electron beam curable insulating resin. of insulating resin, etc.

Among these, an ultraviolet curable insulating resin, more specifically an ultraviolet curable acrylic insulating resin, is preferable because it has a small heat shrinkage when cured and is excellent in energy saving. The thickness of the insulating protective layer 8 is not particularly limited, but from the viewpoint of covering and protecting the conductive Y circuit pattern layer 7, it is 10 μm or more and 20 μm or less, preferably 12 μm or more and 18 μm or less, more preferably about 15 μm. good.

Now, the insulating layer 4 is interposed between the conductive X circuit pattern layer 3 and the conductive Y circuit pattern layer 7, and since it may become a background during inspection, the first insulating layer 5 is colored for inspection. Due to the improvement in brightness difference associated with this coloring, it becomes possible to distinguish the conductive X circuit pattern layer 3, the conductive Y circuit pattern layer 7, and their overlapping portions.

In order to color the first insulating layer 5 , a chromatic colorant is added to the insulating resin of the first insulating layer 5 . This coloring agent enhances the visibility of, for example, the conductive X-circuit pattern layer 3 and the conductive Y-circuit pattern layer 7, and various easily available greens (bamboo green, blue green, dark green, chrome green, Tokiwa color, etc.), It is red, pink, or the like, and is added in an amount of about 1 to 3 parts by mass with respect to 90 to 70 parts by mass of the insulating resin of the first insulating layer 5 .

Such a first insulating layer 5 has a total light transmittance of 86% or less in order to visually grasp the conductive X circuit pattern layer 3, the conductive Y circuit pattern layer 7, and the overlapped part thereof. , and the haze value is set to 9% or more. The total light transmittance (TT) of the first insulating layer 5 is 86% or less, specifically 80% or more and 86% or less, preferably 81% or more and 86% or less, more preferably 82%. % or more and 85.70% or less is good. This is because when the total light transmittance of the first insulating layer 5 is 87% or more, the transparency of the first insulating layer 5 is increased more than necessary, and the distinguishability and visibility are deteriorated. The total light transmittance of this first insulating layer 5 is measured based on ISO 13468-1 and JIS K 7361.

The first insulating layer 5 has a haze (HAZE) value of 9% or more, specifically 10% or more and 93% or less, preferably 12% or more and 93% or less, more preferably 15% or more and 92%. 90% or less is good. This is because when the haze value of the first insulating layer 5 is less than 9%, the transparency of the first insulating layer 5 is excessively increased, resulting in deterioration of distinguishability and visibility. The haze value of the first insulating layer 5 is measured according to JIS K7136 and JIS K7361.

In the above configuration, when the multilayer circuit board is manufactured into a bendable capacitance sensor in the manufacturing process, it is transferred from the manufacturing process to an inspection process, and visually inspected in this inspection process to sort out good products and defective products. After that, good products are shipped.

During this inspection, the conductive X circuit pattern layer 3 is inspected not from both the front and back sides of the multilayer circuit board, but from the base layer 1 side on the back side. When inspected from the base layer 1 side, the first insulating layer 5 in the background of the conductive X circuit pattern layer 3 is colored, and the lightness difference between the conductive X circuit pattern layer 3 and the first insulating layer 5 Since the chroma difference is large, the conductive X circuit pattern layer 3 can be clearly identified visually (see FIG. 2). Therefore, even if a fine conductive line overlapping the conductive Y circuit pattern layer 7 of the conductive X circuit pattern layer 3 is disconnected, the disconnection of this conductive line can be reliably found.

In the inspection, the conductive Y circuit pattern layer 7 is inspected not from both the front and back sides of the multilayer circuit board, but from the insulation protection layer 8 side on the surface. When inspected from the insulating protective layer 8 side, the first insulating layer 5 behind the conductive Y circuit pattern layer 7 is colored, and the lightness difference between the conductive Y circuit pattern layer 7 and the first insulating layer 5 is Since the color saturation difference is increased, the conductive Y circuit pattern layer 7 can be clearly identified visually (see FIG. 3). Therefore, even if a fine conductive line overlapping the conductive X circuit pattern layer 3 of the conductive Y circuit pattern layer 7 is broken, it is possible to reliably find the broken line.

According to the above configuration, since the first insulating layer 5 serving as the background of the conductive X circuit pattern layer 3 and the conductive Y circuit pattern layer 7 is colored, the conductive X circuit pattern layer 3 and the conductive Y circuit pattern are colored. It is possible to accurately distinguish whether it is layer 7 or not. In addition, even if there is a defect in the overlapping part of the conductive X circuit pattern layer 3 and the conductive Y circuit pattern layer 7, the defect can be detected only from one of the front and back sides of the multilayer circuit board when inspecting the multilayer circuit board. can be detected optically with certainty. Further, the positions of the conductive X circuit pattern layer 3 and the conductive Y circuit pattern layer 7 in the XY direction can be determined with high accuracy.

In addition, it is possible to effectively prevent troubles in identifying repaired parts and difficulty in sorting defective multilayer circuit boards from non-defective ones. For example, when a fine conductive line overlapping the conductive Y circuit pattern layer 7 of the conductive X circuit pattern layer 3 is broken, the broken conductive line of the conductive X circuit pattern layer 3 is replaced with the conductive Y It is possible to identify the conductive line of the circuit pattern layer 7 without mistaking it, specify the repaired portion as the laminated insulating layer 2, and quickly repair it. Also, if the first insulating layer 5 is green instead of yellow or the like, it is possible to prevent glare from interfering with the inspection. Furthermore, it is possible to save the trouble of changing the design so that the conductive X circuit pattern layer 3 and the conductive Y circuit pattern layer 7 do not overlap.

In addition, although the flexible base layer 1 is shown in the above-described embodiment, the base layer 1 is not limited to this, and a hard base layer 1 having no flexibility may be used. Moreover, although the single-layer laminated insulating layer 2 is shown in the above-described embodiment, the laminated insulating layer 2 may be formed of transparent first and second transparent laminated insulating layers. Moreover, although the insulating layer 4 is formed of the first and second insulating layers 5 and 6, it may be a colored single-layer insulating layer 4 or a colored three-layer insulating layer 4. FIG.

Alternatively, the conductive Y circuit pattern layer 7 may be laminated on the laminated insulating layer 2 and the conductive X circuit pattern layer 4 may be laminated on the insulating layer 4 . Furthermore, although the transparent insulating protective layer 8 is printed on the surface of the conductive Y circuit pattern layer 7 in the above embodiment, the present invention is not limited to this. For example, on the surface of the conductive Y circuit pattern layer 7, a light-transmissive resin sheet, resin film, or the like can be laminated and adhered as the insulating protective layer 8. FIG.

Examples of multilayer circuit boards according to the present invention will be described below together with comparative examples.
[Example 1]
First, in order to manufacture a multi-layered circuit board for a capacitance sensor, a transparent polyethylene terephthalate resin film having a thickness of 75 μm with excellent heat resistance was prepared as a base layer, and an ultraviolet curable film was applied to the surface of the polyethylene terephthalate resin film. By screen-printing an acrylic insulating resin and curing it by irradiating it with ultraviolet rays, a laminated insulating layer having a thickness of 15 μm was formed transparently.

After laminating the laminated insulating layers in this way, a thermosetting resin-based silver ink is screen-printed on the surface of the laminated insulating layers, dried and cured to form a conductive X circuit pattern layer with a thickness of 8 μm shown in FIG. formed. At this time, the plurality of conductive lines of the conductive X circuit pattern layer were arranged at a pitch of 0.1 mm. A disconnection for testing was formed in a part of the plurality of conductive lines. Also, the width of each conductive line was set to 0.05 mm.

Next, a UV curable acrylic insulating resin is screen-printed on the surface of the conductive X circuit pattern layer, and cured by irradiating with UV rays to laminate a first insulating layer having a thickness of 15 μm having light transmittance. formed. 30 parts by mass of a green colorant [manufactured by Fujikura Kasei Co., Ltd.: product name SN-8400G], which is an insulating paste, was added to the acrylic insulating resin. After the first insulating layer is laminated in this way, an ultraviolet-curing acrylic insulating resin is screen-printed on the surface of the first insulating layer, and cured by irradiating ultraviolet rays to obtain a light-transmitting second insulating layer. was laminated to a thickness of 15 μm.

Next, a thermosetting resin-based silver ink was screen-printed on the surface of the second insulating layer, dried and cured to form a conductive Y circuit pattern layer having a thickness of 8 μm as shown in FIG. At this time, the plurality of conductive lines of the conductive Y circuit pattern layer were arranged at a pitch of 0.1 mm. A portion of the plurality of conductive lines overlapped a break in the conductive line of the conductive X circuit pattern layer. Also, the width of each conductive line was adjusted to 0.05 mm.

After the conductive Y circuit pattern layer is formed, an ultraviolet curable acrylic insulating resin is screen-printed on the surface of the conductive Y circuit pattern layer, and then cured by irradiating with ultraviolet rays to provide an insulation having light transmittance. A protective layer was laminated to a thickness of 15 μm. A multi-layered circuit board for a capacitance sensor was obtained by stacking the insulating protective layers.

After obtaining the multilayer circuit board, the multilayer circuit board was inspected from both the front and back surfaces, and Table 1 shows whether or not the disconnection of the conductive line of the conductive X circuit pattern layer can be visually recognized. Also, the total light transmittance and haze value of the first insulating layer were measured and summarized in Table 1. The total light transmittance of the first insulating layer was measured according to ISO 13468-1 and JIS K 7361 using a spectroscopic haze meter [manufactured by Nippon Denshoku Co., Ltd.: product name SH7000 (PC specification)]. The haze value of the first insulating layer was measured according to JIS K 7361 with a spectroscopic haze meter [manufactured by Nippon Denshoku Co., Ltd.: product name SH7000 (PC specification)].

[Example 2]
Basically, a multi-layered circuit board for a capacitance sensor was manufactured in the same manner as in Example 1, but when the first insulating layer was laminated to a thickness of 15 μm, the acrylic insulating resin did not contain an insulating paste. 20 parts by mass of a green coloring agent [manufactured by Fujikura Kasei Co., Ltd.: product name SN-8400G] was added.

After manufacturing the multilayer circuit board, the multilayer circuit board was inspected from both sides, and Table 1 shows whether or not the disconnection of the conductive line of the conductive X circuit pattern layer can be visually recognized. Also, the total light transmittance and haze value of the first insulating layer were measured and summarized in Table 1.

[Example 3]
Basically, a multi-layered circuit board for a capacitance sensor was manufactured in the same manner as in Example 1, but when the first insulating layer was laminated to a thickness of 15 μm, the acrylic insulating resin did not contain an insulating paste. 10 parts by mass of a green coloring agent [manufactured by Fujikura Kasei Co., Ltd.: product name SN-8400G] was added.

After manufacturing the multilayer circuit board, the multilayer circuit board was inspected from both sides, and Table 1 shows whether or not the disconnection of the conductive line of the conductive X circuit pattern layer can be visually recognized. Also, the total light transmittance and haze value of the first insulating layer were measured and summarized in Table 1.

[Comparative example]
Basically, a multi-layer circuit board for a capacitance sensor was manufactured in the same manner as in Example 1, but when laminating the first insulating layer to a thickness of 15 μm, the green colorant was omitted without being added. and the first insulating layer was colorless and transparent.

After manufacturing the multilayer circuit board, the multilayer circuit board was inspected from both sides, and Table 1 shows whether or not the disconnection of the conductive line of the conductive X circuit pattern layer can be visually recognized. Also, the total light transmittance and haze value of the first insulating layer were measured and summarized in Table 1.

〔evaluation〕
In each example, since the total light transmittance was 86% or less and the haze value was 9% or more, it was possible to clearly distinguish between the conductive X circuit pattern layer and the conductive Y circuit pattern layer. Further, when the conductive X circuit pattern layer of the multilayer circuit board was inspected, it was possible to visually and clearly recognize the broken portion of the conductive line of the conductive X circuit pattern layer from the base layer side.
On the other hand, in the case of the comparative example, the total light transmittance was 88.16% and the haze value was 8.30%. I couldn't tell exactly what it was. In addition, it was not possible to visually recognize the broken portions of the conductive lines of the conductive X circuit pattern layer.

INDUSTRIAL APPLICABILITY The multilayer circuit board according to the present invention is used in the field of manufacturing capacitive sensors and printed wiring boards.

1 base layer 2 laminated insulating layer 3 conductive X circuit pattern layer (first conductive circuit pattern layer)
4 insulating layer 5 first insulating layer 6 second insulating layer 7 conductive Y circuit pattern layer (second conductive circuit pattern layer)
8 insulating protective layer

Claims (4)

comprising a first conductive circuit pattern layer, a light-transmitting insulating layer laminated on the first conductive circuit pattern layer, and a second conductive circuit pattern layer laminated on the insulating layer; Part of the second conductive circuit pattern layer overlaps through an insulating layer, the insulating layer is colored for inspection, the total light transmittance of this insulating layer is 86% or less, and the haze value is of 9% or more . 2. A multi-layer circuit according to claim 1, comprising a flexible light-transmitting base layer and a light-transmitting laminated insulating layer interposed between the base layer and the first conductive circuit pattern layer. substrate. 3. The multilayer circuit board according to claim 1, further comprising a light-transmissive insulating protective layer laminated on the second conductive circuit pattern layer. The insulating layer comprises a first insulating layer laminated on the first conductive circuit pattern layer and a second insulating layer interposed between the first insulating layer and the second conductive circuit pattern layer. Claims 1 and 2, wherein the first and second insulating layers are imparted with optical transparency, and at least the first insulating layer of the first and second insulating layers is colored for inspection. , or the multilayer circuit board according to 3.

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