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US-12628275-B2 - Board assembly, board, and electronic device

US12628275B2US 12628275 B2US12628275 B2US 12628275B2US-12628275-B2

Abstract

Provided is a board assembly including a first board including a first signal line group including signal lines extended in a first direction and lined up in a direction orthogonal to the first direction, and a second board including a second signal line group including signal lines extended in a second direction and lined up in a direction orthogonal to the second direction. The first board and the second board are fixed such that the signal lines included in the first signal line group and the second signal line group are connected in line, and the second board includes an additional signal line separated from the second signal line group in a thickness direction of the second board and extended across a second connection terminal group including a plurality of connection terminals connected to the second signal line group or the first signal line group.

Inventors

  • Haruhiko HISANO
  • Jun Kadowaki

Assignees

  • WACOM CO., LTD.

Dates

Publication Date
20260512
Application Date
20230828

Claims (11)

  1. 1 . A board assembly comprising: a first board including a first signal line group including a plurality of signal lines formed by a first conductive layer and extended in a first direction and lined up in a second direction orthogonal to the first direction; and a second board including a second signal line group formed by a second conductive layer and including a plurality of signal lines extended in the first direction and lined up in the second direction orthogonal to the first direction, wherein the first board and the second board are fixed such that the signal lines included in the first signal line group and the second signal line group are connected in line, and wherein the second board includes a first additional signal line separated from the second signal line group in a thickness direction of the second board and extended across the second signal line group at a crimp section at which the first board and the second board are crimped together and the first conductive layer and the second conductive layer are electrically connected.
  2. 2 . The board assembly according to claim 1 , wherein: the first board includes an additional signal line separated from the first signal line group in a thickness direction of the first board and extended across a first connection terminal group including a plurality of connection terminals connected to the first signal line group or the second signal line group.
  3. 3 . The board assembly according to claim 1 , further comprising: an anisotropic conductive film containing a thermosetting resin between the first board and the second board, wherein the first board and the second board are fixed by being heated and pressed at the crimp section, and wherein the crimp section includes the anisotropic conductive film.
  4. 4 . The board assembly according to claim 3 , wherein: the second board includes a second additional signal line separated from the second signal line group in the thickness direction of the second board and extended across at the crimp section at which the first board and the second board are crimped together and the first conductive layer and the second conductive layer are electrically connected, and the first additional signal line is spaced apart from the second additional signal line.
  5. 5 . The board assembly according to claim 3 , wherein: the second board includes at least one additional signal line at a position including the crimp section.
  6. 6 . The board assembly according to claim 3 , wherein: the second board includes at least two additional signal lines across the crimp section along the second direction.
  7. 7 . The board assembly according to claim 1 , wherein: the second signal line group is provided on a first main surface of the second board, and the first additional signal line is provided on a second main surface of the second board.
  8. 8 . The board assembly according to claim 1 , wherein: the second signal line group and the first additional signal line are provided on a first main surface of the second board.
  9. 9 . The board assembly according to claim 1 , wherein: the first board is a detection board including a touch sensor, the second board is a flexible board with flexibility, and the touch sensor is connected to an integrated circuit that, in operation, controls the touch sensor through the first signal line group and the second signal line group.
  10. 10 . The board assembly according to claim 9 , wherein the integrated circuit is provided on the flexible board.
  11. 11 . An electronic device comprising: a board assembly including: a first board including a first signal line group formed by a first conductive layer and including a plurality of signal lines extended in a first direction and lined up in a second direction orthogonal to the first direction, and a second board including a second signal line group formed by a second conductive layer and including a plurality of signal lines extended in the first direction and lined up in the second direction orthogonal to the first direction, wherein the first board and the second board are fixed such that the signal lines included in the first signal line group and the second signal line group are connected in line, and wherein the second board includes an additional signal line separated from the second signal line group in a thickness direction of the second board and extended across a crimp section at which the first board and the second board are crimped together and the first conductive layer and the second conductive layer are electrically connected.

Description

BACKGROUND Technical Field The present disclosure relates to a board assembly, a board, and an electronic device. Description of the Related Art Conventionally, there is known a technique of inspecting whether signal lines installed on an electronic circuit board are disconnected. For example, an inspection method related to a touch sensor of capacitance type including a plurality of line electrodes arranged in a two-dimensional grid is disclosed in Japanese Patent Laid-Open No. 2019-145066. A crimping process using, for example, an anisotropic conductive film (ACF) is used to connect boards in some cases. The crimping process has an advantage that the height and the pitch can be more easily reduced than in the connection using soldering or connector. However, the pressure fitting work increases the probability of poor connection or disconnection. BRIEF SUMMARY The present disclosure has been made in view of the problem, and an object of the present disclosure is to provide a board assembly, a board, and an electronic device that can inspect the connection state of boards with a simpler wiring structure. A first aspect of the present disclosure provides a board assembly including a first board including a first signal line group including a plurality of signal lines extended in a first direction and lined up in a direction orthogonal to the first direction, and a second board including a second signal line group including a plurality of signal lines extended in a second direction and lined up in a direction orthogonal to the second direction. The first board and the second board are fixed such that the signal lines included in the first signal line group and the second signal line group are connected in line, and the second board includes an additional signal line separated from the second signal line group in a thickness direction of the second board and extended across a second connection terminal group including a plurality of connection terminals connected to the second signal line group or the first signal line group. A second aspect of the present disclosure provides a board including a base, a signal line group on a first main surface of the base and including a plurality of lined up signal lines or a connection terminal group provided on the first main surface of the base and including a plurality of lined up connection terminals, and one or more additional signal lines provided on a second main surface of the base and extended across the signal line group or the connection terminal group. A third aspect of the present disclosure provides an electronic device including the board assembly according to the first aspect of the present disclosure or the board according to the second aspect of the present disclosure. According to the present disclosure, the connection state of the boards can be inspected with a simpler wiring structure. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 is an exploded perspective view of an electronic device provided with a sensor board group as a board assembly in a first embodiment of the present disclosure; FIG. 2 is a partial plan view of the sensor board group illustrated in FIG. 1; FIG. 3 is a cross-sectional view along a line A-A illustrated in FIG. 2; FIG. 4 depicts an example of a determination method of the connection state in the sensor board group of FIGS. 2 and 3; FIG. 5 is a cross-sectional view of a sensor board group in a first modification of the first embodiment; FIG. 6 is a partial plan view of a sensor board group in a second modification of the first embodiment; FIG. 7 is a plan view of a display board in a second embodiment of the present disclosure; FIG. 8 is a partial plan view of a sensor board group as a board assembly in a third embodiment of the present disclosure; and FIG. 9 depicts an example of a determination method of the connection state in the sensor board group of FIG. 8. DETAILED DESCRIPTION Embodiments of the present disclosure will now be described with reference to the attached drawings. To facilitate the understanding of the description, the same reference signs are provided as much as possible to the same constituent elements in the drawings, and the description thereof will not be repeated. Note that the present disclosure is not limited to the following first to third embodiments and modifications, and it is obvious that the present disclosure can be freely changed without departing from the scope of the disclosure. In addition, configurations may be arbitrarily combined as long as there is no technical contradiction. First Embodiment A board assembly and an electronic device in a first embodiment of the present disclosure will be described with reference to FIGS. 1 to 4. Overall Configuration FIG. 1 is an exploded perspective view of an electronic device 10 provided with a sensor board group 18 as a board assembly in the first embodiment of the present disclosure. The electronic device 10 may be various types of dev