An electronic device including a thermosetting bonding sheet may include: a base substrate including a base substrate body and a plurality of base pads disposed on the base substrate body, a connection substrate including a connection substrate body facing the base substrate body, a plurality of connection pads disposed on the connection substrate body and including a pad hole, and a plurality of connection lines disposed on the connection substrate body and connected to the plurality of connection pads, a solder, at least a portion of which is inserted into the pad hole, disposed on the base pad and configured to electrically connect the base pad to the connection pad, and a thermosetting bonding sheet provided between the base substrate body and the connection substrate body, bonded to the base substrate body and the connection substrate body, and enclosing the solder

A first flexible electronic circuit includes a non-conductive substrate and a conductive trace layer, including a bonding pad, on a surface of the non-conductive substrate. A second flexible electronic circuit likewise includes a substrate and a conductive trace layer, including a bonding pad, on a surface of the non-conductive substrate. The second flexible electronic circuit also includes a conductive interface layer on an opposite surface of the non-conductive substrate to the bonding pad. A plurality of vias, filled with conductive material, extend through the substrate of the second flexible electronic circuit and couple the conductive interface layer to the bonding pad. The bonding pads are brought in contact with each other, and energy (e.g., ultrasonic energy or thermal energy) is applied to the conductive interface layer until the bonding pads are bonded (e.g., ultrasonically welded or soldered) to each other.

A metal foil layer includes a metal foil layer upper main surface, a metal foil layer lower main surface with a surface roughness greater than that of the metal foil layer upper main surface, and a metal foil layer side surface that is a surface of the metal foil layer excluding the metal foil layer upper main surface and the metal foil layer lower main surface. The metal foil layer upper main surface is in contact with an upper resin layer. The metal foil layer lower main surface is in contact with a lower resin layer. A portion of a lower main surface of the upper resin layer and a portion of an upper main surface of the lower resin layer are in contact with each other to define a layer interface. In a cross section of the metal foil layer, the metal foil layer side surface includes an outer point and an inner point where the upper resin layer is in contact with the side surface, and the inner point is below the outer point and inward of the outer point.

A display device includes a display panel, a first circuit board, a control unit disposed on the first circuit board, a second circuit board, and a coupling film which electrically couples the control unit and the second circuit board to each other. The coupling film includes a first coupling part including a first region attached to the first circuit board, and a second region overlapping the display panel when viewed in a thickness direction of the display panel, a second coupling part including a third region attached to the second circuit board, and a fourth region overlapping the display panel when viewed in the thickness direction of the display panel, and a third coupling part coupled to each of the second region and the fourth region to electrically couple the first coupling part and the second coupling part to each other.

A disk device includes a magnetic disk, a magnetic head, a flexible printed circuit board, an electronic component, and a wall. The flexible printed circuit board is electrically connected to the magnetic head. The electronic component is mounted on the flexible printed circuit board. The wall has rigidity higher than the flexible printed circuit board and is attached to the flexible printed circuit board. The flexible printed circuit board with a first through hole includes a first surface facing the electronic component with a gap, and a second surface opposite the first surface and facing the wall, the first through hole being open to the first surface and the second surface to communicate with the gap. The wall is provided with a second through hole penetrating the wall to communicate with the first through hole.

Devices including a substrate and a plurality of coil portions disposed on the substrate. The plurality of coil portions electrically coupled to form a coil structure.

A detection device includes a sensor substrate provided with a plurality of photosensors, a control board provided with a control circuit configured to control the photosensors, and a flexible printed circuit board provided with wiring configured to electrically couple the sensor substrate to the control board. The flexible printed circuit board is provided with a plurality of cutting indication lines for changing a length between the sensor substrate and the flexible printed circuit board.

A circuit member joint structure includes a first circuit member including a first main surface on which a first mounting electrode is provided, a second circuit member including a second main surface on which a second mounting electrode is provided, a conductive joining material with which the first mounting electrode and the second mounting electrode are joined to each other, and an insulating joining material with which an end portion of the first circuit member and an end portion of the second circuit member are joined to each other. The first circuit member includes a first recess on the first main surface and spaced away from the first mounting electrode, and at least a portion of the insulating joining material is disposed in the first recess.

A printed circuit board includes a first transmission line provided on an insulating base, a first ground conductor, a notch portion that exposes a part of the first ground conductor, a conductor provided in the notch portion and electrically connected to the first ground conductor, and a first electrode exposed on a main surface of the insulating base facing a flexible board and electrically connected to the first transmission line. The flexible board includes a second transmission line provided on an insulating sheet, a second ground conductor, a second electrode exposed on a main surface of the insulating sheet facing the printed circuit board and connected to the second transmission line, and a third electrode exposed on the main surface of the insulating sheet and connected to the second ground conductor. The conductor and the third electrode are connected by solder.

A display device includes a display panel including a plurality of display pads at least some of which at least a portion extend in a first direction and are arranged in a second direction intersecting the first direction, and a flexible circuit board including circuit pads, at least some of which at are electrically connected to the display pads, and circuit lines connected to the circuit pads. The circuit pads include at least one dummy pad, and the circuit lines include a dummy circuit line, of which at least a portion of is connected to the at least one dummy pad. The dummy circuit line includes a first portion connected to the at least one dummy pad and a second portion spaced apart from the first portion by a gap.