JP-7856599-B2 - Shielded printed circuit board

Inventors

• 山内 志朗
• 田島 宏
• 春名 裕介
• 香月 貴彦

Assignees

• タツタ電線株式会社

Dates

Publication Date

20260511

Application Date

20230315

Priority Date

20181211

Claims (12)

1. A printed circuit board comprising a base film, a printed circuit formed on the base film, and a coverlay covering the printed circuit, A first insulating layer is arranged to cover one side of the printed circuit board, It has a second insulating layer that is arranged to cover the other side of the printed circuit board, A portion of the first insulating layer forms an extended portion of the first insulating layer located outside the edge of the printed circuit board. A portion of the second insulating layer forms an extended portion of the second insulating layer located outside the edge of the printed circuit board. The first insulating layer extension end and the second insulating layer extension end face each other, The space between the first insulating layer and one surface of the printed circuit board, the space between the second insulating layer and the other surface of the printed circuit board, and the region where the extension end of the first insulating layer and the extension end of the second insulating layer face each other are filled without gaps with a conductive resin composition. A shielded printed circuit board characterized in that the thickness of the conductive resin composition filled between the first insulating layer and the second insulating layer in the region where the extension end of the first insulating layer and the extension end of the second insulating layer face each other is 1/30 to 9/10 times the thickness of the printed circuit board.
2. The shielded printed circuit board according to claim 1, wherein a first shielding layer is formed between the first insulating layer and the conductive resin composition.
3. The shielded printed circuit board according to claim 2, wherein the first shielding layer is made of metal.
4. The shielded printed circuit board according to claim 2, wherein the first shield layer comprises a conductive resin composition for the first shield layer.
5. A shielded printed circuit board according to any one of claims 1 to 4, wherein a second shielding layer is formed between the second insulating layer and the conductive resin composition.
6. The shielded printed circuit board according to claim 5, wherein the second shielding layer is made of metal.
7. The shielded printed circuit board according to claim 5, wherein the second shield layer comprises a conductive resin composition for the second shield layer.
8. The shielded printed circuit board according to any one of claims 1 to 7, wherein the conductive resin composition is an isotropic conductive resin composition.
9. The conductive resin composition comprises conductive particles and a resin. The shielded printed circuit board according to any one of claims 1 to 8, wherein the weight percentage of the conductive particles is 3 to 90% by weight.
10. The printed circuit of the printed wiring board includes a ground circuit, and a portion of the ground circuit is exposed to the outside. The shielded printed circuit board according to any one of claims 1 to 9, wherein the ground circuit and the conductive resin composition are electrically connected.
11. The shielded printed circuit board according to any one of claims 1 to 10, wherein the first insulating layer is at least one selected from polyimide resin, polyamideimide resin, polyamide resin, polyetherimide resin, polyesterimide resin, polyethernitrile resin, polyethersulfone resin, polyphenylene sulfide resin, polyethylene terephthalate resin, polypropylene resin, crosslinked polyethylene resin, polyester resin, polybenzimidazole resin, polyimide resin, polyimideamide resin, polyetherimide resin, and polyphenylene sulfide resin.
12. The shielded printed circuit board according to any one of claims 1 to 11, wherein the second insulating layer is at least one selected from polyimide resin, polyamideimide resin, polyamide resin, polyetherimide resin, polyesterimide resin, polyethernitrile resin, polyethersulfone resin, polyphenylene sulfide resin, polyethylene terephthalate resin, polypropylene resin, crosslinked polyethylene resin, polyester resin, polybenzimidazole resin, polyimide resin, polyimideamide resin, polyetherimide resin, and polyphenylene sulfide resin .

Description

This invention relates to a shielded printed circuit board. Flexible printed circuit boards (PCBs) are widely used in electronic devices such as mobile phones, video cameras, and laptop computers, where miniaturization and increased functionality are rapidly progressing, to integrate circuits into complex mechanisms. Furthermore, their excellent flexibility allows them to be used for connecting movable parts, such as printer heads, to control units. Electromagnetic shielding is essential in these electronic devices, and flexible printed circuit boards used within these devices are increasingly being shielded (hereinafter also referred to as "shielded PCBs"). Examples of shielded printed circuit boards include those comprising a printed circuit board in which printed circuits and coverlays are sequentially arranged on a base film, and an electromagnetic wave shielding film consisting of an adhesive layer, a shielding layer laminated on the adhesive layer, and an insulating layer laminated on the shielding layer. An electromagnetic shielding film is laminated onto a printed circuit board such that the adhesive layer is in contact with the printed circuit board, and a shielded printed circuit board is obtained when the adhesive layer is bonded to the printed circuit board. Furthermore, Patent Document 1 discloses a shielded printed circuit board in which shielding layers are formed on both sides of the printed circuit board, and a method for manufacturing the same. Japanese Patent Application Publication No. 8-125380 Figure 1 is a schematic process diagram showing an example of the printed circuit board preparation step in the method for manufacturing a shielded printed circuit board according to the first embodiment of the present invention.Figure 2 is a schematic process diagram showing an example of the first electromagnetic wave shielding film preparation step in the method for manufacturing a shielded printed circuit board according to the first embodiment of the present invention.Figure 3 is a schematic process diagram showing an example of the second electromagnetic wave shielding film preparation step in the method for manufacturing a shielded printed circuit board according to the first embodiment of the present invention.Figure 4 is a schematic process diagram showing an example of the first electromagnetic wave shielding film arrangement step in the method for manufacturing a shielded printed circuit board according to the first embodiment of the present invention.Figure 5 is a schematic process diagram showing an example of the second electromagnetic wave shielding film placement step in the method for manufacturing a shielded printed circuit board according to the first embodiment of the present invention.Figure 6 is a schematic process diagram showing an example of the overlapping process in the manufacturing method of a shielded printed circuit board according to the first embodiment of the present invention.Figure 7 is a schematic process diagram showing an example of a preliminary pressing step in the manufacturing method of a shielded printed circuit board according to the first embodiment of the present invention.Figure 8 is a schematic process diagram showing an example of the protective film peeling step in the method for manufacturing a shielded printed circuit board according to the first embodiment of the present invention.Figure 9A is a schematic process diagram showing an example of the main pressing step in the method for manufacturing a shielded printed circuit board according to the first embodiment of the present invention.Figure 9B is a schematic process diagram showing an example of the main pressing step in the method for manufacturing a shielded printed circuit board according to the first embodiment of the present invention.Figure 10 is a schematic process diagram showing an example of the printed circuit board preparation step in the method for manufacturing a shielded printed circuit board according to the second embodiment of the present invention.Figure 11 is a schematic process diagram showing an example of the first electromagnetic wave shielding film preparation step in a method for manufacturing a shielded printed circuit board according to a second embodiment of the present invention.Figure 12 is a schematic process diagram showing an example of the second electromagnetic wave shielding film preparation step in the method for manufacturing a shielded printed circuit board according to the second embodiment of the present invention.Figure 13 is a schematic process diagram showing an example of the first electromagnetic wave shielding film arrangement step in a method for manufacturing a shielded printed circuit board according to a second embodiment of the present invention.Figure 14 is a schematic process diagram showing an example of the second electromagnetic wave shielding film arrangement step in the method for manufacturing a shielded printed circuit board accor