Design method for conductive films

Abstract

To enable the arrangement design of conductive particles for a conductive film that is easily adaptable for connection to a mini-LED or a micro-LED substrate to be effortlessly carried out.SOLUTION: Provided is a method for designing the arrangement of conductive particles P in a conductive film when connecting a terminal in length of L1 and in width of L2 using the conductive film where the conductive particles P are held in an insulating resin layer. First, it is assumed that the conductive particles P are arranged at lattice points of a rectangular or an orthorhombic lattice, and the lattice axis is orthogonal to the longitudinal or the lateral direction of the conductive film. Then, the number density, etc., of the conductive particles P in the conductive film are set, and then, from lattice points that are at the distance of terminal length L1 or less from one lattice point A, a lattice point B is selected, where the angle that a line linking said lattice point and the lattice point A forms with the lateral direction of the film is smallest, and a rotation angle α of the lattice is found, where the lattice point A and the lattice point B overlap in the lateral direction of the film when the lattice is rotated around the lattice point A, with the inclination angle of the lattice axis of the conductive film determined by the angle α.SELECTED DRAWING: Figure 3B

Claims

1. A method for designing the arrangement of conductive particles in a conductive film, in which conductive particles of a predetermined particle size are held in an insulating resin layer when connecting terminals with terminal length L1 and terminal width L2 (where L1 ≥ L2), in a plan view, First, the arrangement of conductive particles is assumed to be at the grid points of a rectangular or rhombic grid, and to have grid axes perpendicular to the longitudinal or transverse direction of the conductive film (hereinafter also referred to as the longitudinal or transverse direction of the film). Then, the number density of conductive particles in the conductive film, the pitch d1 of the conductive particles on the grid axis in the longitudinal direction of the film corresponding to the number density, and the pitch d2 of the conductive particles on the grid axis in the transverse direction of the film (d2 = a * d1, where a is a coefficient) are set. Next, among the grid points that are at a distance of terminal length L1 or less from one grid point A, a grid point B is selected in which the line connecting that grid point and grid point A makes the smallest angle with the film's short-side direction. The grid is then rotated around grid point A to determine the rotation angle α of the grid where grid points A and B overlap in the film's short-side direction, and this angle α is used to determine the inclination angle of the grid axis of the conductive film.

2. The design method according to claim 1, wherein the grid is a square grid.

3. When the terminal length L1 and terminal width L2 are 7 to 1000 μm, the number density of conductive particles is 500 particles / mm². 2 ~1500000 pieces / mm 2 The design method according to claim 1 or 2, wherein the setting is within the range.

4. The design method according to any one of claims 1 to 3, wherein the particle size of the conductive particles is 1.0 to 30 μm.

5. A design method according to any one of claims 1 to 4, wherein the grid axes are inclined at an angle α with respect to the short direction of the film, and when adjacent axes are designated as the first array axis and the second array axis, the angle α is determined such that conductive particles on the first array axis and conductive particles on the second array axis do not overlap in the longitudinal direction of the film.

6. d1・cosα≦L2 or d²・sinα≦L1 A design method according to any one of claims 1 to 5, wherein the pitches d1 and d2 of conductive particles are determined such that the following conditions are met.

7. A method for manufacturing a transfer mold used to transfer conductive particles onto an insulating resin layer in a predetermined arrangement pattern, comprising the step of processing a metal plate into recesses or protrusions with a predetermined arrangement pattern designed by the method described in any one of claims 1 to 6.

8. The method according to claim 7, wherein the metal plate is processed by cutting.

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