Search

JP-7856111-B2 - Laminate for image display devices, image display device, and module

JP7856111B2JP 7856111 B2JP7856111 B2JP 7856111B2JP-7856111-B2

Inventors

  • 榊 真史
  • 木下 一樹
  • 飯村 慶太
  • 武 誠司
  • 川口 修司

Assignees

  • 大日本印刷株式会社

Dates

Publication Date
20260511
Application Date
20221004
Priority Date
20211004

Claims (20)

  1. A wiring substrate having a substrate including a first surface and a second surface located opposite to the first surface, and a mesh wiring layer disposed on the first surface of the substrate, A first adhesive layer located on the first surface side of the substrate, A second adhesive layer located on the second surface side of the substrate, The intermediate layer is located between the wiring board and the first adhesive layer and between the wiring board and the second adhesive layer, The substrate is transparent, A laminate for an image display device, wherein a portion of the substrate is disposed in a portion of the region between the first adhesive layer and the second adhesive layer.
  2. The laminate for an image display device according to claim 1, wherein the intermediate layer is located between the wiring substrate and the first adhesive layer, and also between the wiring substrate and the second adhesive layer.
  3. The laminate for an image display device according to claim 1, wherein the thickness of the intermediate layer is 1 μm or more and 50 μm or less.
  4. The laminate for an image display device according to claim 1, wherein the refractive index of the intermediate layer is 1.4 or more and 1.6 or less.
  5. The laminate for an image display device according to claim 1, wherein the difference between the refractive index of the intermediate layer and the refractive index of the first adhesive layer is 0.1 or less, the difference between the refractive index of the intermediate layer and the refractive index of the substrate is 0.1 or less, and the difference between the refractive index of the intermediate layer and the refractive index of the second adhesive layer is 0.1 or less.
  6. The laminate for an image display device according to claim 1, wherein the dielectric loss tangent of the substrate is 0.002 or less.
  7. The laminate for an image display device according to claim 1, wherein the relative permittivity of the substrate is 2 or more and 10 or less.
  8. The aforementioned wiring board has radio wave transmission and reception capabilities, as described in claim 1, for use as a laminate for an image display device.
  9. The laminate for an image display device according to claim 1, wherein the wiring board further comprises a power supply unit electrically connected to the mesh wiring layer, and the mesh wiring layer includes a transmission unit connected to the power supply unit and a transmitting/receiving unit connected to the transmission unit.
  10. A laminate for an image display device according to any one of claims 1 to 9, An image display device comprising a display device formed by stacking the aforementioned image display device laminates.
  11. A wiring substrate having a substrate including a first surface, a second surface located opposite the first surface, and a third surface located between the first surface and the second surface, and a mesh wiring layer disposed on the first surface of the substrate, A first adhesive layer located on the first surface side of the substrate, The substrate comprises a second adhesive layer located on the second surface side, The substrate is transparent, A portion of the substrate is placed in a portion of the region between the first adhesive layer and the second adhesive layer. The third surface of the substrate is covered by at least one of the first adhesive layer and the second adhesive layer. A laminate for an image display device, wherein the surface roughness Ra of the third surface is 0.005 μm or more and 0.5 μm or less.
  12. The laminate for an image display device according to claim 11, wherein the thickness of the substrate is 2 μm or more and 50 μm or less.
  13. The laminate for an image display device according to claim 11, wherein the thickness of the first adhesive layer is 1.5 times or more the thickness of the substrate and 300 μm or less.
  14. The laminate for an image display device according to claim 11, wherein the thickness of the second adhesive layer is 1.5 times or more the thickness of the substrate and 300 μm or less.
  15. The laminate for an image display device according to claim 11, wherein the first adhesive layer and the second adhesive layer each contain an acrylic resin.
  16. The laminate for an image display device according to claim 11, wherein a dummy wiring layer is provided around the mesh wiring layer, electrically independent of the mesh wiring layer.
  17. The laminate for an image display device according to claim 11, wherein the dielectric loss tangent of the substrate is 0.002 or less.
  18. The laminate for an image display device according to claim 11, wherein the relative permittivity of the substrate is 2 or more and 10 or less.
  19. The aforementioned wiring board has radio wave transmission and reception functions, as described in claim 11, for the laminated image display device.
  20. The laminate for an image display device according to claim 11, wherein the wiring board further comprises a power supply unit electrically connected to the mesh wiring layer, and the mesh wiring layer includes a transmission unit connected to the power supply unit and a transmitting/receiving unit connected to the transmission unit.

Description

The embodiments of this disclosure relate to a laminate for an image display device, an image display device, and a module. Currently, mobile devices such as smartphones and tablets are becoming more sophisticated, smaller, thinner, and lighter. These mobile devices use multiple communication bands. Therefore, multiple antennas are required, corresponding to each communication band. For example, mobile devices are equipped with multiple antennas, such as antennas for telephone, Wi-Fi (Wireless Fidelity), 3G (Generation), 4G (Generation), LTE (Long Term Evolution), Bluetooth (registered trademark), and NFC (Near Field Communication). However, with the miniaturization of mobile devices, the space available for antenna installation is limited, and the freedom of antenna design is narrowing. Furthermore, because antennas are built into a limited space, radio wave sensitivity is not always satisfactory. Therefore, film antennas that can be mounted on the display area of mobile devices are being developed. This film antenna is a transparent antenna in which an antenna pattern is formed on a transparent substrate. The antenna pattern is formed by a mesh-like conductive mesh layer. It includes a conductive portion as the part where the opaque conductive layer is formed, and numerous openings as the non-formed portion. Japanese Patent Publication No. 2011-66610Patent No. 5636735 specificationPatent No. 5695947 specification This embodiment provides a laminate for an image display device, an image display device, and a module that make it difficult to visually detect the presence of a wiring board within the image display device. Furthermore, in conventional film antennas, the conductive mesh layer is often fixed to other layers by a transparent adhesive layer such as OCA (Optical Clear Adhesive). Because OCA is a flexible material, it is difficult to maintain horizontal alignment between the conductive mesh layer and the ground layer. In this case, it is difficult to sufficiently improve antenna characteristics. This embodiment provides a laminate for an image display device and an image display device that can improve antenna characteristics. A first aspect of the present disclosure is a laminate for an image display device, comprising: a substrate including a first surface and a second surface located opposite to the first surface; a mesh wiring layer disposed on the first surface of the substrate; a first adhesive layer located on the first surface side of the substrate; a second adhesive layer located on the second surface side of the substrate; and an intermediate layer located at least one of the spaces between the wiring substrate and the first adhesive layer and between the wiring substrate and the second adhesive layer, wherein the substrate is transparent, and a portion of the substrate is disposed in a portion of the space between the first adhesive layer and the second adhesive layer. A second aspect of the present disclosure is a laminate for an image display device according to the first aspect described above, wherein the intermediate layer is located between the wiring substrate and the first adhesive layer, and also between the wiring substrate and the second adhesive layer. A third aspect of this disclosure is a laminate for an image display device according to the first or second aspect described above, wherein the thickness of the intermediate layer may be 1 μm or more and 50 μm or less. A fourth aspect of this disclosure is a laminate for an image display device according to each of the first to third aspects described above, wherein the refractive index of the intermediate layer may be 1.40 or more and 1.60 or less. A fifth aspect of this disclosure is a laminate for an image display device according to each of the first to fourth aspects described above, wherein the difference between the refractive index of the intermediate layer and the refractive index of the first adhesive layer is 0.1 or less, the difference between the refractive index of the intermediate layer and the refractive index of the substrate is 0.1 or less, and the difference between the refractive index of the intermediate layer and the refractive index of the second adhesive layer may also be 0.1 or less. A sixth aspect of this disclosure is a laminate for an image display device according to each of the first to fifth aspects described above, wherein the dielectric loss tangent of the substrate may be 0.002 or less. A seventh aspect of this disclosure is a laminate for an image display device according to each of the first to sixth aspects described above, wherein the relative permittivity of the substrate may be 2 or more and 10 or less. An eighth aspect of this disclosure is a laminate for an image display device according to each of the first to seventh aspects described above, wherein the wiring board may have a radio wave transmission and reception function. A ninth aspect of the present disclosure is a laminate for an