JP2011146421A - Terminal connection structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a terminal connection structure that improves reliability of electric connection. <P>SOLUTION: The terminal connection structure includes a flexible printed wiring board 10 having a plurality of first connection terminals 12, 13 provided to a first insulating substrate 11, a ridged printed wiring board 20 having a plurality of second connection terminals 22, 23, opposed to the plurality of first connection terminals 12, 13, provided to a second insulating substrate 21, and an anisotropic conductive film 30 laminated between the flexible printed wiring board 10 and ridged wiring board 20 and electrically connecting the plurality of first connection terminals 12, 13 and the plurality of second connection terminals 22, 23 to each other, the first insulating substrate 11 being curved convexly toward the second insulating substrate 21 between the plurality of first connection terminals 12, 13. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a terminal connection structure using an anisotropic conductive film.

  There is known an ACF (anisotropic conductive film) bonding structure in which an anisotropic conductive film is laminated between an electronic component and a substrate, and the electrode of the electronic component and the electrode of the substrate are electrically bonded (for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-16949

  In the above ACF bonding structure, if the electrodes of the electronic component and the substrate are thick, the anisotropic conductive film needs to be thick. However, at present, there is a technical limit to forming an anisotropic conductive film with a thickness greater than a predetermined thickness. For this reason, in the ACF bonding structure described above, if the electrodes of the electronic component and the substrate are thick, the anisotropic conductive film cannot be sufficiently interposed between the electronic component and the substrate, and a void is formed between the electronic component and the substrate. As a result, there is a problem that reliability of electrical connection may be lowered.

  The problem to be solved by the present invention is to provide a terminal connection structure that improves the reliability of electrical connection.

  The terminal connection structure according to the present invention includes a flexible printed wiring board in which a plurality of first connection terminals are provided on a first insulating substrate, and a plurality of second connections respectively facing the plurality of first connection terminals. A rigid printed wiring board provided with a connection terminal on a second insulating substrate, and is laminated between the flexible printed wiring board and the rigid printed wiring board, and a plurality of the first connection terminals and a plurality of the second connections. An anisotropic conductive film that electrically connects the terminals to each other, and the first insulating substrate faces the second insulating substrate between the plurality of first connection terminals. It is characterized by being curved in a convex shape.

  The terminal connection structure according to the present invention includes a flexible printed wiring board in which a plurality of first connection terminals are provided on a first insulating substrate, and a plurality of second connections respectively facing the plurality of first connection terminals. An electronic component having a connection terminal provided on a terminal forming surface, and the flexible printed wiring board and the electronic component are stacked, and the plurality of first connection terminals and the plurality of second connection terminals are electrically connected to each other. An anisotropic conductive film connected to the first insulating substrate, wherein the first insulating substrate is curved in a convex shape toward the terminal formation surface between the plurality of first connection terminals. It is characterized by.

  The terminal connection structure according to the present invention includes a first flexible printed wiring board in which a plurality of first connection terminals are provided on a first insulating substrate, and a plurality of first connection terminals facing each of the plurality of first connection terminals. A second flexible printed wiring board provided on a second insulating substrate, a second connecting terminal is laminated between the first flexible printed wiring board and the second flexible printed wiring board; An anisotropic conductive film that electrically connects each of the first connection terminals and the plurality of second connection terminals, and the first insulating substrate is between the plurality of first connection terminals. And the second insulating substrate is curved in a convex shape.

  In the above invention, the second insulating substrate may be curved in a convex shape toward the first insulating substrate between the plurality of second connection terminals.

  In the above invention, the following expression (1) may be satisfied.

但し、上記（１）式において、Ｌは湾曲した前記第１の絶縁性基板から前記第２の絶縁性基板又は前記端子形成面までの最短距離であり、Ｈ_１は前記第１の接続端子の厚さであり、Ｈ_２は前記第２の接続端子の厚さである。

However, in the above formula (1), L is the shortest distance from the curved first insulating substrate to the second insulating substrate or the terminal forming surface, and H ₁ is the first connecting terminal. is the thickness, H ₂ is the thickness of the second connection terminal.

  According to the present invention, the first insulating substrate is curved in a convex shape toward the second insulating substrate or the terminal forming surface between the plurality of first connection terminals. Connection reliability can be improved.

FIG. 1 is a cross-sectional view showing a terminal connection structure of a printed wiring board according to the first embodiment of the present invention. FIG. 2 is a front view showing an outline of the loop stiffness test. FIG. 3 is a cross-sectional view showing a modified example of the terminal connection structure of the printed wiring board according to the first embodiment of the present invention. FIG. 4: is sectional drawing which shows the manufacturing method of the printed wiring board in 1st Embodiment of this invention (the 1). FIG. 5: is sectional drawing which shows the manufacturing method of the printed wiring board in 1st Embodiment of this invention (the 2). FIG. 6 is a cross-sectional view showing a terminal connection structure of a printed wiring board according to the second embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< first embodiment >>
FIG. 1 is a cross-sectional view showing a terminal connection structure of a printed wiring board according to the present embodiment, FIG. 2 is a front view showing an outline of a loop stiffness test, and FIG. It is sectional drawing shown.

  The terminal connection structure in the present embodiment is a structure that electrically connects between connection terminals 12 and 13 (described later) and connection terminals 22 and 23 (described later) in the printed wiring board 1.

  As shown in FIG. 1, the printed wiring board 1 includes a first flexible printed wiring board (FPC) 10, a rigid printed wiring board 20, an anisotropic conductive film 30, and the like. It is equipped with.

  As shown in FIG. 1, the first flexible printed wiring board 10 includes a first insulating substrate 11 and first and second connection terminals 12 and 13.

  The first insulating substrate 11 is made of a flexible material such as polyimide or polyethylene terephthalate. In addition, as a material used for the 1st insulating board | substrate 11, it is preferable that it is 50 N (25 mm conversion value) or less in a loop stiffness test (JPCA-TM02-2009).

  As a specific test method of the loop stiffness test, as shown in FIG. 2, the both ends 11a and 11b of the first insulating substrate 11 are gripped by the handles 41, and the handles 11a and 11b are brought close to each other. 41 is slid to curve the central portion 11c of the first insulating substrate 11 in a convex shape. In this state, the central portion 11c of the first insulating substrate 11 is pressed by the load cell 42, and the repulsive force from the first insulating substrate 11 is measured.

  As shown in FIG. 1, the first insulating substrate 11 is formed on a second insulating substrate 21 of a rigid printed wiring board 20 described later between first and second connection terminals 12 and 13 described later. It curves in a convex shape.

  As shown in FIG. 1, the first and second connection terminals 11 and 12 are terminals for inputting / outputting electric signals to / from the rigid printed wiring board 20 (described later). Among these, the first connection terminal 12 is electrically connected to a third connection terminal 22 (described later) of the rigid printed wiring board 20, and the second connection terminal 13 is a fourth connection terminal of the rigid printed wiring board 20. 23 (described later).

As shown in FIG. 1, the first and second connection terminals 12 and 13 are provided on the lower surface of the first insulating substrate 11, and the first connection terminal 12 is arranged on the left side in the drawing, Two connection terminals 13 are arranged on the right side in the figure. The second connecting terminal 13 has a first connection terminal 12 first gap _{S 1} apart.

The thickness of the first and second connection terminals 12 and 13, as shown in FIG. 1, are both the first thickness H _1. Such first and second connection terminals 12 and 13 are made of a conductive material such as copper, silver, or solder.

  As shown in FIG. 1, the rigid printed wiring board 20 includes a second insulating substrate 21 and third and fourth connection terminals 22 and 23.

  The second insulating substrate 21 is made of a hard material such as glass epoxy resin, and has a flat plate shape.

As shown in FIG. 1, the third and fourth connection terminals 22 and 23 are terminals for inputting / outputting electrical signals to / from the first flexible printed wiring board 10. The third and fourth connection terminals 22, 23 are provided on the upper surface of the second insulating substrate 21, and on the left side in the drawing so that the third connection terminal 22 faces the first connection terminal 12. The fourth connection terminal 23 is arranged on the right side in the figure so as to face the second connection terminal 13. The fourth connection terminal 23, the third is from the connecting terminal 22 second intervals _{S 2} apart. The second interval S ₂ is substantially the same as the first interval S ₁ between the first and second connection terminals 12 and 13 (S ₁ ≈S ₂ ).

The thickness of the third and fourth connection terminals 22 and 23, as shown in FIG. 1, are both the second thickness H _2. The third and fourth connection terminals 22 and 23 are made of a conductive material such as copper, silver, or solder.

  The anisotropic conductive film 30 includes an adhesive layer 31 and conductive particles 32.

  The adhesive layer 31 is laminated between the first flexible printed wiring board 10 and the rigid printed wiring board 20 and adheres between the first insulating substrate 11 and the second insulating substrate 21. The adhesive layer 31 is made of a thermosetting adhesive such as an epoxy resin.

  The conductive particles 32 are a plurality of conductive particles dispersed in the adhesive layer 31. As shown in FIG. 1, the conductive particles 32 are sandwiched between the first and third connection terminals 12 and 22 to electrically connect the first and third connection terminals 12 and 22. In addition, the second and fourth connection terminals 13 and 23 are electrically connected between the second and fourth connection terminals 13 and 23. The conductive particles 32 are made of, for example, nickel, silver, copper, or a spherical resin particle whose surface is plated with metal.

The thickness of the anisotropic conductive film 30 before heat curing (including provisional curing) is determined by the dimensions (width, thickness H ₁ , H ₂ , spacing S ₁ , S of the connection terminals 12, 13, 22, 23. ₂ ) and has a tendency to depend on the thicknesses H ₁ and H ₂ in particular.

For example, the widths of the connection terminals 12, 13, 22, and 23 are all 100 μm, the first and second intervals S ₁ and S ₂ are both 100 μm, and the first and second thicknesses H ₁ and H ₂ are both the same. In an example in which the thickness is 40 μm, if the first insulating substrate 11 is in a flat state, the thickness of the anisotropic conductive film 30 before heat curing is preferably 60 μm or more.

  However, at present, it is technically difficult to form an anisotropic conductive film thick, and the upper limit of the thickness is 50 μm. For this reason, in the above example, an anisotropic conductive film having a sufficient thickness (60 μm or more) cannot be interposed between the first flexible printed wiring board and the rigid printed wiring board. For this reason, a void is generated between the first flexible printed wiring board and the rigid printed wiring board, and the void contracts or expands due to thermal shock, whereby the first and third connection terminals 12 and 22 (second and fourth connection terminals). Connection terminals 13 and 23) may approach or separate from each other, and the reliability of electrical connection of the printed wiring board (terminal connection structure) may deteriorate.

  On the other hand, in the printed wiring board 1 (terminal connection structure) in the present embodiment, as shown in FIG. 1, the first insulating substrate 11 of the first flexible printed wiring board 10 is the first and second. Between the connection terminals 12, 13, the rigid printed wiring board 20 is curved in a convex shape toward the second insulating substrate 21, and between the first flexible printed wiring board 10 and the rigid printed wiring board 20. The space formed in (the portion where the anisotropic conductive film 30 is interposed) is small. That is, the cross-sectional area A surrounded by the first and second insulating substrates 11 and 21 and the connection terminals 12, 13, 22, and 23 satisfies the following expression (2).

但し、上記（２）式において、Ｈ_１は第１及び第２の接続端子１２,１３の厚さであり、Ｈ_２は第３及び第４の接続端子２２,２３の厚さであり、Ｓ_１は第１及び第２の接続端子１２,１３間の間隔である。

However, in the above equation (2), H ₁ is the thickness of the first and second connection terminals 12 and 13, H ₂ is the thickness of the third and fourth connection terminals 22 and 23, and S Reference numeral ₁ denotes an interval between the first and second connection terminals 12 and 13.

  For this reason, even the thin anisotropic conductive film 30 can be sufficiently interposed between the first flexible printed wiring board 10 and the rigid printed wiring board 20. Thereby, generation | occurrence | production of the void between the 1st flexible printed wiring board 10 and the rigid printed wiring board 20 is suppressed, the tolerance with respect to the thermal shock of the printed wiring board 1 (terminal connection structure) improves, and the reliability of electrical connection Improves.

  For example, in the above example, an anisotropic conductive film having a thickness of 50 μm or less (for example, 45 μm) may be used by curving the first insulating substrate in a convex shape toward the second insulating substrate. The first flexible printed wiring board and the rigid printed wiring board can be electrically connected with excellent reliability.

  Moreover, in such a printed wiring board 1 (terminal connection structure), it is preferable to satisfy | fill following (1) Formula.

但し、上記（１）式において、Ｌは湾曲した第１の絶縁性基板１１から第２の絶縁性基板２１までの最短距離であり（図１参照）、Ｈ_１は第１及び第２の接続端子１２,１３の厚さであり、Ｈ_２は第３及び第４の接続端子２２,２３の厚さである。

However, in the above formula (1), L is the shortest distance from the curved first insulating substrate 11 to the second insulating substrate 21 (see FIG. 1), and H ₁ is the first and second connections. The thickness of the terminals 12 and 13, and H ₂ is the thickness of the third and fourth connection terminals 22 and 23.

In particular, the first flexible printed wiring board 10 and the rigid printed wiring can be formed with a thinner anisotropic conductive film 30 by largely curving the first insulating substrate 11 and reducing L in the above equation (1). The reliability of the electrical connection between the plates 20 can be improved. Alternatively, the first flexible wiring board 10 in which the first thickness H ₁ of the first and second connection terminals 12, 13 is formed thick, and the second thickness of the third and fourth connection terminals 22, 23. is a rigid printed wiring board 20 which is formed thick H _2, it is possible to improve the reliability of the electrical connection between the.

  Moreover, since the usage-amount of the anisotropic conductive film 30 reduces in production of the printed wiring board 1, the cost of the printed wiring board 1 can be reduced.

  In the printed wiring board 1 according to the present embodiment, the first flexible printed wiring board 10 is connected to the rigid printed wiring board 20. However, instead of the rigid printed wiring board 20, a second flexible printed wiring board (not used) is used. The first flexible printed wiring board 10 may be connected to the figure. In this case, the second insulating substrate (not shown) is made of a flexible material such as polyimide or polyethylene terephthalate.

  Further, as shown in FIG. 3, the first flexible printed wiring board 10 may be connected to the electronic component 50 instead of the rigid printed wiring board 20. In this case, the third and fourth connection terminals 52 and 53 may be constituted by solder bumps provided on the terminal formation surface 51 of the electronic component 50.

  In this way, the first flexible printed wiring board 10 and the electronic component 50 are connected by connecting the first flexible printed wiring board 10 to the electronic component 50 in a state where the first insulating substrate 11 is curved. It is possible to suppress the generation of voids between them and improve the resistance to thermal shock and the reliability of electrical connection. Further, by suppressing the generation of voids in this way, the stress transmitted to the electronic component 50 along with the expansion or contraction of the void can be reduced, and the warpage of the electronic component 50 can be suppressed.

  Moreover, also when connecting the 1st flexible printed wiring board 10 to the electronic component 50 in this way, it is preferable to satisfy | fill following (1) Formula.

但し、上記（１）式において、Ｌは湾曲した第１の絶縁性基板１１から端子形成面５１までの最短距離であり（図３参照）、Ｈ_１は第１及び第２の接続端子１２,１３の厚さであり、Ｈ_２は第３及び第４の接続端子５２,５３の厚さである。

However, in the above formula (1), L is the shortest distance from the curved first insulating substrate 11 to the terminal forming surface 51 (see FIG. 3), and H ₁ is the first and second connection terminals 12, 13, and H ₂ is the thickness of the third and fourth connection terminals 52 and 53.

  In the present embodiment, the two connection terminals 12 and 13 are provided on the first flexible printed wiring board 10, and the two connection terminals 22 are also provided on the rigid printed wiring board 20 (second flexible printed wiring board or electronic component). , 23 (connection terminals 52, 53) are provided, but the number of connection terminals is not particularly limited as long as it is two or more. For example, three connection terminals may be provided on each of the first flexible printed wiring board and the rigid printed wiring board (second flexible printed wiring board or electronic component). Also in this case, the first insulating substrate of the first flexible printed wiring board is curved convexly toward the second insulating substrate or the terminal formation surface between the respective connection terminals.

  Next, the manufacturing method of the printed wiring board in this embodiment is demonstrated.

  4 and 5 are cross-sectional views showing a method for manufacturing a printed wiring board in the present embodiment.

  In the method for manufacturing the printed wiring board 1 in the present embodiment, the anisotropic conductive film 30 is first laminated on the rigid printed wiring board 20, as shown in FIG. Next, the anisotropic conductive film 30 is heated and pressurized to temporarily press the rigid printed wiring board 20 (the adhesive layer 31 of the anisotropic conductive film 30 is bonded to the rigid printed wiring board 20 without being completely cured). ). Such heating and pressurization can be performed by using, for example, an oven and a laminator. For example, when the adhesive layer 31 is made of an epoxy resin, the heating temperature is about 60 ° C. to 80 ° C. Yes, the pressure is about 1 MPa.

  Next, the first connection terminal 12 and the third connection terminal 22 are aligned, the second connection terminal 13 and the fourth connection terminal 23 are aligned, and the anisotropic conductive film 30 is formed without heating. Temporarily press-bonded to the first flexible printed wiring board 10.

  Next, as shown in FIG. 5, the first flexible printed wiring board 10 is pressed while being heated by the crimping tool 62 through the buffer sheet 61, and the anisotropic conductive film 30 is finally crimped (the adhesive layer 31 is completely bonded). To cure.). For example, when the adhesive layer 31 is made of an epoxy resin, the heating temperature for the main pressure bonding is about 200 ° C., and the pressure is about 3 MPa to 5 MPa.

  During the main pressure bonding, the first and third connection terminals 12 and 22 are connected via the conductive particles 32 of the anisotropic conductive film 30, and the second and fourth connection terminals 13 and 23 are anisotropic. The conductive particles are connected via conductive particles 32 of the conductive film 30.

  Here, portions of the buffer sheet 61 corresponding to the first and second connection terminals 12 and 13 are sandwiched and compressed between the first flexible printed wiring board 10 and the crimping tool 62. On the other hand, the portion of the buffer sheet 61 corresponding to the area between the first and second connection terminals 12 and 13 (third and fourth connection terminals 22 and 23) is connected to the first insulating substrate 11 and anisotropic conductive material. Since it is only supported by the film 30, it tries to keep the original thickness without being compressed.

  As described above, the buffer sheet 61 is deformed following the arrangement of the first and second connection terminals 12 and 13 of the first flexible printed wiring board 10, thereby the first and second connection terminals 12 and 13. In the meantime, the first insulating substrate 11 is curved in a convex shape toward the second insulating substrate 21.

  When the adhesive layer 31 of the anisotropic conductive film 30 is cured in this state, the shape of the first insulating substrate 11 is maintained and the first and third connection terminals 12 and 22 are electrically connected. And the second and fourth connection terminals 13 and 23 are held in an electrically connected state.

  Here, examples of the material of the buffer sheet 61 described above include polytetrafluoroethylene (PTFE), silicone rubber, and the like. In addition, although the buffer sheet 61 before pressing in the present embodiment has a flat plate shape (not shown), a corresponding portion between the first and second connection terminals 12 and 13 is projected in advance. The shape may be different.

  The crimping tool 62 has a main body 62a and a convex 62b, and is made of, for example, stainless steel (SUS). The main body 62a has a plate shape, and abuts the first flexible printed wiring board 10 on the lower surface. The convex portion 62b is disposed on the upper surface of the main body portion 62a. A pressing force from a power source (not shown) and heat from a heater (not shown) are transmitted to the convex portion 62b.

  The first and second connection terminals 12 and 13 in the present embodiment correspond to an example of the first connection terminal of the present invention, and the third and fourth connection terminals 22, 23, 52, and 53 corresponds to an example of the second connection terminal of the present invention.

Next, a second embodiment will be described.

<< Second Embodiment >>
FIG. 6 is a cross-sectional view showing a terminal connection structure of a printed wiring board in the present embodiment.

  The printed wiring board (terminal connection structure) 1a in the present embodiment is different from the first embodiment in the configuration of the second flexible printed wiring board 70, but the other configurations are the same as those in the first embodiment. Only the differences from the first embodiment will be described below, and portions having the same configuration as in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

  As shown in FIG. 6, the second insulating substrate 71 of the second flexible printed wiring board 70 includes a second insulating substrate 71 between the third and fourth connection terminals 72 and 73. The first insulating substrate 11 is curved in a convex shape.

For this reason, in the printed wiring board 1a (terminal connection structure) in the present embodiment, a space (an anisotropic conductive film 30) formed between the first flexible printed wiring board 10 and the second flexible printed wiring board 70. Is further reduced, and the thinner anisotropic conductive film 30 improves the reliability of electrical connection between the first flexible printed wiring board 10 and the second flexible printed wiring board 70. be able to.

  Moreover, also in such a printed wiring board 1a (terminal connection structure), it is preferable to satisfy | fill following (1) Formula.

但し、上記（１）式において、Ｌは湾曲した第１の絶縁性基板１１から第２の絶縁性基板７１までの最短距離であり（図６参照）、Ｈ_１は第１及び第２の接続端子１２,１３の厚さであり、Ｈ_２は第３及び第４の接続端子７２,７３の厚さである。

However, in the above equation (1), L is the shortest distance from the curved first insulating substrate 11 to the second insulating substrate 71 (see FIG. 6), and H ₁ is the first and second connections. The thickness of the terminals 12 and 13, and H ₂ is the thickness of the third and fourth connection terminals 72 and 73.

In particular, the first and second insulating substrates 11 and 71 are largely curved to reduce L in the above formula (1), thereby further reducing the thickness of the first flexible printed wiring board with the thinner anisotropic conductive film 30. The reliability of the electrical connection between 10 and the second flexible printed wiring board 70 can be improved. Alternatively, the first flexible wiring board 10 in which the first thickness H ₁ of the first and second connection terminals 12, 13 is formed thick, and the second thickness of the third and fourth connection terminals 72, 73. is a second flexible printed circuit board 70 which is formed thick H _2, it is possible to improve the reliability of the electrical connection between the.

  Note that the second insulating substrate 71 is formed through the adhesive layer 31 by the force that the first insulating substrate 11 curved in a convex shape tries to restore in the main pressure bonding step. By being pulled toward, it curves in a convex shape.

  The first and second connection terminals 12 and 13 in this embodiment correspond to an example of the first connection terminal of the present invention, and the third and fourth connection terminals 72 and 73 in this embodiment are the present invention. This corresponds to an example of the second connection terminal.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1, 1a ... Printed wiring board 10 ... 1st flexible printed wiring board 11 ... 1st insulating board 12, 22 ... Connection terminal 20 ... Rigid printed wiring board 21 ... 2nd insulating board 22, 23 ... 3rd Connection terminal 30 ... Anisotropic conductive film 31 ... Adhesive layer 32 ... Conductive particle 50 ... Electronic component 51 ... Terminal forming surface 52, 53 ... Connection terminal 70 ... Second flexible printed wiring board 71 ... Second insulation Substrate 72, 73 ... connection terminal

Claims (5)

A flexible printed wiring board having a plurality of first connection terminals provided on a first insulating substrate;
A rigid printed wiring board in which a plurality of second connection terminals respectively facing the plurality of first connection terminals are provided on a second insulating substrate;
An anisotropic conductive film laminated between the flexible printed wiring board and the rigid printed wiring board and electrically connecting the plurality of first connection terminals and the plurality of second connection terminals, respectively,
The terminal connection structure, wherein the first insulating substrate is curved convexly toward the second insulating substrate between the plurality of first connection terminals. A flexible printed wiring board having a plurality of first connection terminals provided on a first insulating substrate;
An electronic component in which a plurality of second connection terminals respectively facing the plurality of first connection terminals are provided on a terminal formation surface;
An anisotropic conductive film laminated between the flexible printed wiring board and the electronic component, and electrically connecting the plurality of first connection terminals and the plurality of second connection terminals, respectively.
The terminal connection structure, wherein the first insulating substrate is curved in a convex shape toward the terminal formation surface between the plurality of first connection terminals. A first flexible printed wiring board having a plurality of first connection terminals provided on a first insulating substrate;
A second flexible printed wiring board in which a plurality of second connection terminals respectively facing the plurality of first connection terminals are provided on a second insulating substrate;
An anisotropic conductive film laminated between the first flexible printed wiring board and the second flexible printed wiring board and electrically connecting the plurality of first connection terminals and the plurality of second connection terminals respectively. And comprising
The terminal connection structure, wherein the first insulating substrate is curved convexly toward the second insulating substrate between the plurality of first connection terminals. The terminal connection structure according to claim 3,
The terminal connection structure, wherein the second insulating substrate is curved in a convex shape toward the first insulating substrate between the plurality of second connection terminals. The terminal connection structure according to any one of claims 1 to 4,
The terminal connection structure characterized by satisfy | filling following (1) Formula.

However, in the above formula (1), L is the shortest distance from the curved first insulating substrate to the second insulating substrate or the terminal forming surface, and H ₁ is the first connecting terminal. is the thickness, H ₂ is the thickness of the second connection terminal.

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