Electronic component

Abstract

To prevent damage to a connected board.SOLUTION: An electronic component 100 includes a connected substrate 1 and a flexible printed wiring board 3. The connected substrate 1 includes a first base sheet 11, an electric circuit 13 formed on the first base sheet 11, a first terminal forming portion E1 formed on at least one end of the first base sheet, and a plurality of first terminals 15 formed on the first terminal forming end E1 and connected to the electric circuit 13. The flexible printed wiring board 3 includes a second base sheet 31, a second terminal forming portion E2 formed on at least one end of the second base sheet, and a plurality of second terminals 33 formed on the second terminal forming end E2 and connected to the first terminals 15. A wide portion 31a extending in the X direction in which the plurality of second terminals 33 are arranged is formed in the second terminal forming end E2. Dummy terminals 39, 39' are formed on at least one of the wide portion 31a and a portion of the first base sheet 11 facing the wide portion 31a.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electronic component including a substrate to be connected provided with a predetermined electric circuit and a flexible printed wiring board connected to the substrate to be connected.

Background Art

[0002] Conventionally, an electronic component including a substrate to be connected formed with a predetermined electric circuit such as a touch sensor and a flexible printed wiring board for connecting the electric circuit to an external device is known (see, for example, Patent Document 1).

[0003] In the above electronic component, a first terminal connected to the predetermined electric circuit is formed at an end of the substrate to be connected, and a second terminal electrically connected to the first terminal is formed at an end of the flexible printed wiring board. Then, the end of the flexible printed wiring board where the second terminal is formed is fixed to the end of the substrate to be connected where the first terminal is formed by a fixing member such as an anisotropic conductive member.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above electronic component, for example, when the flexible printed wiring board is deformed such as being lifted in a direction perpendicular to the substrate to be connected, the substrate to be connected may be damaged. In particular, among the ends of the substrate to be connected where the flexible printed wiring board is fixed, a portion close to the end of the flexible printed wiring board may be damaged.

[0006] An object of the present invention is to prevent damage to a substrate to be connected in an electronic component including a substrate to be connected provided with a predetermined electric circuit and a flexible printed wiring board connected to the substrate to be connected.

Means for Solving the Problem

[0007] Hereinafter, a plurality of aspects will be described as means for solving the problem. These aspects can be arbitrarily combined as necessary. An electronic component according to a first aspect includes a substrate to be connected and a flexible printed wiring board. The substrate to be connected has a first base sheet, a predetermined electric circuit formed on the first base sheet, a first terminal forming end portion provided at at least one end of the first base sheet, and a plurality of first terminals formed on the first terminal forming end portion and connected to the electric circuit. The flexible printed wiring board has a second base sheet, a second terminal forming end portion provided at at least one end of the second base sheet, and a plurality of second terminals formed on the second terminal forming end portion and connected to the first terminals of the substrate to be connected by a fixing member.

[0008] In the electronic component according to the first aspect, a wide portion extending in a first direction, which is a direction in which the plurality of second terminals are arranged, is formed at the second terminal forming end portion. Further, dummy terminals are formed on at least one of the wide portion and a portion of the first base sheet facing the wide portion.

[0009] In the electronic component according to the first aspect, a wide portion extending in a first direction, which is a direction in which the plurality of second terminals are arranged, is provided at the second terminal forming end portion of the second base sheet of the flexible printed wiring board, that is, at a connection portion between the second base sheet and the first base sheet. By providing the wide portion, when the second base sheet is deformed, the stress acting on the first base sheet due to this deformation is dispersed, and the concentration of stress at a specific location of the first base sheet is suppressed. As a result, it is possible to suppress damage to the substrate to be connected due to deformation of the flexible printed wiring board.

[0010] In addition, dummy terminals are formed on at least one of the wide portion and the portion of the first base sheet facing the wide portion. By providing dummy terminals in the wide portion and the portion corresponding to the wide portion in the first base sheet, when the first base sheet and the second base sheet are fixed by a fixing member, the fixing member is more likely to be filled in the wide portion without gaps. As a result, it becomes difficult to form a space such as a bubble in the fixing member between the wide portion and the first base sheet, so that the wide portion and the first base sheet can be fixed more firmly.

[0011] In the electronic component according to the second aspect, the length of the wide portion in the first direction may be 1 time or more the length of the wide portion in the second direction perpendicular to the first direction. Thereby, when the second base sheet is deformed, the stress acting on the first base sheet can be more effectively dispersed.

[0012] In the electronic component according to the third aspect, the first terminal forming end portion of the first base sheet and the second terminal forming end portion of the second base sheet may be arranged parallel to each other. In this case, the end portion of the wide portion in the second direction perpendicular to the first direction may protrude from the end portion of the first base sheet. Thereby, it is possible to further suppress stress concentration at a specific location of the first base sheet.

[0013] In the electronic component according to the fourth aspect, the wide portion may not be provided with a wiring pattern for connecting the dummy terminal and a predetermined device. Thereby, since the length of the wide portion in the second direction can be reduced, the ability to disperse the stress acting on the substrate to be connected by the wide portion can be improved.

[0014] In the electronic component according to the fifth aspect, the second base sheet may have a plurality of terminal forming end portions. In this case, the wide portion may be provided only at the outermost portion of the plurality of terminal forming end portions in the first direction of the second base sheet. Thereby, since the number of wide portions formed can be reduced, the cost of the electronic component due to an increase in the area of the second base sheet can be reduced.

[0015] In the electronic component according to the sixth aspect, the dummy terminals may be arranged close to both ends in the second direction perpendicular to the first direction of the wide portion. Thereby, since the length of the wide portion in the second direction can be reduced, the ability to disperse the stress acting on the connection target substrate due to the wide portion can be improved.

[0016] In the electronic component according to the seventh aspect, a plurality of dummy terminals may be provided side by side in the first direction. In this case, the arrangement interval in the first direction of the plurality of dummy terminals may be the same as the arrangement interval in the first direction of the plurality of second terminals. Thereby, since the fixing states by the fixing member can be made the same between the forming portions of the plurality of second terminals and the forming portions of the plurality of dummy terminals, the connection target substrate and the flexible printed wiring board can be fixed uniformly.

[0017] In the electronic component according to the eighth aspect, an R cut may be formed in the connection portion with the second base sheet in the wide portion. In this case, the dimension (radius of curvature of R) of the R cut may be in the range of 0.1 mm to 1.5 mm, and most preferably in the range of 0.3 mm to 1.0 mm. Thereby, since large C cuts and R cuts are not formed at the boundary portion between the wide portion and the second base sheet, the length of the wide portion in the second direction can be reduced, and the ability to disperse the stress acting on the connection target substrate due to the wide portion can be improved.

Effects of the Invention

[0018] By providing a wide portion at the second terminal forming end of the second base sheet of the flexible printed wiring board, when the second base sheet of the flexible printed wiring board is deformed, it is possible to suppress the generation of a large stress on the first base sheet of the connection target substrate. As a result, breakage of the connection target substrate can be suppressed.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5A

Figure 5B

Figure 5C

Figure 6A

Figure 6B

Embodiments for Carrying Out the Invention

[0020] 1. First Embodiment Hereinafter, the electronic component 100 of the present embodiment will be described with reference to FIGS. 1 to 4. FIG. 1 is a perspective view of the electronic component 100. FIG. 2 is a cross-sectional view when the end of the electronic component 100 is cut in the X direction. FIG. 3A is a cross-sectional view when the first and second terminal portions of the electronic component 100 are cut in the Y direction. FIG. 3B is a cross-sectional view when the wide portion and dummy terminal portion of the electronic component 100 are cut in the Y direction. FIG. 4 is an enlarged plan view near the terminal forming end of the electronic component 100. In the following description, the width direction of the electronic component 100 is defined as the X direction, the length direction is defined as the Y direction, and the thickness direction is defined as the Z direction. The electronic component 100 includes a substrate to be connected 1 and a flexible printed wiring board 3.

[0021] The substrate to be connected 1 is a flexible substrate on which a predetermined electric circuit is formed. The substrate to be connected 1 has a first base sheet 11, an electric circuit 13, and a plurality of first terminals 15. The first base sheet 11 is a plate-like member formed of a flexible material (for example, a resin material or a plastic material). The first base sheet 11 is, for example, a plate-like member formed of cycloolefin polymer (COP). The thickness of the first base sheet 11 can be, for example, about 100 μm.

[0022] The electric circuit 13 is a circuit that realizes a predetermined function. The electric circuit 13 is formed on the first base sheet 11. The electric circuit 13 is, for example, a touch sensor that detects the contact of a contact member such as a finger on the surface. The electric circuit 13 is, for example, a capacitive touch sensor, a resistive film touch sensor, or the like. The electronic component 100 including the electric circuit 13 that is a touch sensor is incorporated into, for example, a smartphone, a mobile computer, a game machine, or a touch screen.

[0023] The plurality of first terminals 15 are formed side by side in the X direction, which is the direction in which the plurality of first terminals 15 are arranged, at an end portion in the Y direction (length direction) on the first base sheet 11 (referred to as the first terminal forming end portion E1). The number of formed first terminals 15 can be appropriately determined according to the type of the electric circuit 13 and the like. The first terminal 15 is connected to the electric circuit 13 by a first wiring pattern 17. The first terminal 15 is electrically connected to the second terminal 33 of the flexible printed wiring board 3. That is, the first terminal 15 is a terminal for electrically connecting the electric circuit 13 to a predetermined device (for example, an external device provided separately from the substrate to be connected 1 and the flexible printed wiring board 3, an electric circuit (for example, a control circuit) formed on the second base sheet 31 of the flexible printed wiring board 3, etc.) via the flexible printed wiring board 3. The first terminal 15 and the first wiring pattern 17 are formed of a conductive material such as copper (Cu), silver (Ag), gold (Au), or aluminum (Al). The thickness of the first terminal 15 is, for example, about several hundred nm.

[0024] On the side where the flexible printed wiring board 3 of the substrate to be connected 1 is fixed, a cover member 5 is fixed so as to cover the substrate to be connected 1. In the electronic component 100, the flexible printed wiring board 3 is disposed between the substrate to be connected 1 and the cover member 5. The cover member 5 is fixed to the substrate to be connected 1 by a transparent adhesive portion 51. The cover member 5 is, for example, a glass cover panel, a polycarbonate cover panel, or a thin display (e.g., a liquid crystal display, an organic EL display).

[0025] In the above-described electronic component 100, the first terminal forming end portion E1 of the first base sheet 11 (i.e., the forming portion of the first terminal 15) deforms accordingly when the flexible printed wiring board 3 (second base sheet 31) deforms.

[0026] The flexible printed wiring board 3 realizes an electrical connection between the electrical circuit 13 of the substrate to be connected 1 and a predetermined device. The flexible printed wiring board 3 includes a second base sheet 31 and a plurality of second terminals 33.

[0027] The second base sheet 31 is a plate-like member formed of a flexible material (e.g., a resin material, a plastic material). The second base sheet 31 can be formed of, for example, polyimide (PI). In addition to polyimide (PI), the second base sheet 31 can also be formed of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyetherimide (PEI), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), unsaturated polyethylene, or the like. Further, the second base sheet 31 may be a composite of a resin and an inorganic material, and can be configured using, for example, glass epoxy. The thickness of the second base sheet 31 can be, for example, about several tens of μm (50 μm to 60 μm).

[0028] A plurality of second terminals 33 are arranged in the X direction (width direction), which is the direction in which the plurality of second terminals 33 are arranged, so as to correspond to the plurality of first terminals 15 of the substrate to be connected 1 at the end in the Y direction (length direction) on the second base sheet 31 (referred to as the second terminal forming end E2). The number of formed second terminals 33 can be the same as the number of formed first terminals 15. The number of formed second terminals 33 may be different from the number of first terminals 15.

[0029] The second terminal 33 is connected to a predetermined device by the second wiring pattern 35. The predetermined device is, for example, an external device provided separately from the substrate to be connected 1 and the flexible printed wiring board 3, and / or an electric circuit formed on the second base sheet 31 of the flexible printed wiring board 3 (for example, a control circuit for controlling the electric circuit 13 of the substrate to be connected 1). The second terminal 33 is electrically connected to the first terminal 15 of the substrate to be connected 1. That is, the second terminal 33 is a terminal for electrically connecting the electric circuit 13 of the substrate to be connected 1 and the above-mentioned predetermined device. The second terminal 33 and the second wiring pattern 35 are formed of a conductive material such as copper (Cu), silver (Ag), gold (Au), or aluminum (Al), for example. The thickness of the second terminal 33 is, for example, about several tens of μm (for example, about 10 μm to 30 μm).

[0030] As shown in FIG. 3A, the second wiring pattern 35 is protected by the protective layer 37. The protective layer 37 can be formed of, for example, polyimide (PI). In addition to polyimide (PI), the protective layer 37 can also be formed of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyetherimide (PEI), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), unsaturated polyethylene, epoxy resin, acrylic resin, etc.

[0031] The second terminal 33 of the flexible printed wiring board 3 is electrically connected to the first terminal 15 of the substrate to be connected 1 by a conductive fixing member 7. That is, the second terminal forming end portion E2 where the second terminal 33 of the flexible printed wiring board 3 is formed is fixed by the fixing member 7 to the first terminal forming end portion E1 where the first terminal 15 of the first base sheet 11 of the substrate to be connected 1 is formed. That is, the first base sheet 11 and the second base sheet 31 are fixed and connected to each other at the Y-direction ends of these substrates.

[0032] The fixing member 7 for electrically connecting the first terminal 15 and the second terminal 33 is, for example, an anisotropic conductive member. The anisotropic conductive member is, for example, an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP). The anisotropic conductive film (ACF) is a film in which fine conductive particles are dispersed in a film-like binder resin, and is a film for imparting conductivity only in the thickness direction of the film. The anisotropic conductive paste (ACP) is a member in which fine conductive particles are dispersed in a fluid binder resin, and imparts conductivity only between terminals (that is, between the first terminal 15 and the second terminal 33) that are pressure-bonded with the anisotropic conductive paste interposed therebetween. The above binder resin is, for example, an epoxy resin or an acrylic resin. Further, the conductive particles include, for example, particles of metal, metal alloy, metal oxide, carbon and graphite, and those in which insulating particles are coated with metal. Examples of the metal used for the conductive particles include nickel, iron, copper, aluminum, tin, lead, chromium, cobalt, silver, and gold.

[0033] When the above-described anisotropic conductive member is used as the fixing member 7, the anisotropic conductive member is compressed (crimped) while being sandwiched between the first base sheet 11 and the second base sheet 31. As a result, the anisotropic conductive member enters the space between the plurality of second terminals 33, and the anisotropic conductive member is filled between the first base sheet 11 and the second base sheet 31 without any gaps. As a result, it becomes difficult to form a space such as a bubble in the fixing member 7 between the first base sheet 11 and the second base sheet 31, so that the first base sheet 11 and the second base sheet 31 can be fixed more firmly.

[0034] Also, the conductive particles contained in the anisotropic conductive member between the first terminal 15 and the second terminal 33 electrically connect the first terminal 15 and the second terminal 33. On the other hand, in a location where the first terminal 15 and the second terminal 33 do not exist, the anisotropic conductive member is solidified with the conductive particles dispersed, so that a path through which current flows is not formed by the conductive particles. That is, a location where the first terminal 15 and the second terminal 33 do not exist is substantially an insulator.

[0035] In the electronic component 100, when the second base sheet 31 of the flexible printed wiring board 3 is deformed, stress acts on the first base sheet 11 of the substrate 1 to be connected due to this deformation. In particular, stress concentrates on the portion of the first terminal forming end portion E1 of the first base sheet 11 that contacts the end portion in the X direction (width direction) of the second base sheet 31.

[0036] In particular, when the first base sheet 11 is weaker in strength than the second base sheet 31, for example, when the first base sheet 11 is formed of cycloolefin polymer (COP) and the second base sheet 31 is formed of polyimide (PI), due to the stress acting on the first base sheet 11 due to the deformation of the second base sheet 31, the first base sheet 11 may be damaged starting from the portion of the first terminal forming end portion E1 of the first base sheet 11 that contacts the end portion of the second base sheet 31.

[0037] Therefore, in the electronic component 100, a wide portion 31a extending in the X direction (width direction), which is the direction in which a plurality of second terminals 33 are arranged from the end portion, is provided at the end portion in the X direction (width direction) of the second terminal forming end portion E2 of the second base sheet 31, and the wide portion 31a is fixed to the first terminal forming end portion E1 of the first base sheet 11 by a fixing member 7.

[0038] By providing a wide portion 31a extending in the X direction, which is the direction in which a plurality of second terminals 33 are arranged, at the end portion of the second terminal forming end portion E2 of the second base sheet 31, that is, at the connection portion between the second base sheet 31 and the first base sheet 11, when the second base sheet 31 of the flexible printed wiring board 3 is deformed, the stress acting on the first base sheet 11 of the connected substrate 1 due to this deformation is dispersed, and the concentration of stress at a predetermined location of the first base sheet 11 (for example, the portion in contact with the end portion of the second base sheet 31) is suppressed. As a result, it is possible to prevent the first base sheet 11 of the connected substrate 1 from being damaged due to the deformation of the flexible printed wiring board 3.

[0039] The ability of the wide portion 31a to disperse the stress acting on the first base sheet 11 is greater as the width (length d1 in the Y direction) of the wide portion 31a is smaller. That is, it is preferable that the length d1 in the Y direction of the wide portion 31a is small. The length d1 of the wide portion 31a can be, for example, several millimeters (for example, about 2 to 3 mm).

[0040] As shown in FIG. 3B, in order to reduce the length d1 in the Y direction of the wide portion 31a, the wide portion 31a is not provided with a wiring pattern for connecting a dummy terminal 39, which will be described later, to a predetermined device. In this way, by making the width (length d1 in the Y direction) of the wide portion 31a as small as possible, the ability to disperse the stress acting on the first base sheet 11 of the connected substrate 1 can be improved, so that damage to the connected substrate 1 can be suppressed.

[0041] Also, it has been found that the ability of the wide portion 31a to disperse the stress acting on the first base sheet 11 is greater as the length (length d2 in the X direction) of the wide portion 31a is longer. That is, it is preferable that the length d2 of the wide portion 31a is large.

[0042] To verify this, when the flexible printed wiring board 3 pulled up the first base sheet 11, the tensile strength that the first base sheet 11 could withstand was examined by changing the length d2 of the wide portion 31a. As a result, when the length (the length d2 in the X direction) of the wide portion 31a was made approximately the same as the width (the length d1 in the Y direction) of the wide portion 31a (that is, d2 / d1≈1), the first base sheet 11 had resistance to a tensile force about twice the tensile force at which the first base sheet was damaged when the wide portion 31a was not provided (that is, d2 = 0). Further, when the length of the wide portion 31a was made approximately twice the width of the wide portion 31a (that is, d2 / d1≈2), the first base sheet 11 had resistance to a tensile force about three times the tensile force at which the first base sheet was damaged when the wide portion 31a was not provided.

[0043] Thus, by setting the length d2 in the X direction of the wide portion 31a to be 1 time or more the length d1 in the Y direction of the wide portion 31a, when the second base sheet 31 of the flexible printed wiring board 3 is deformed, the stress acting on the first base sheet 11 of the substrate 1 to be connected can be more effectively dispersed.

[0044] As shown in FIGS. 3B and 4, the second terminal forming end E2 of the second base sheet 31 of the flexible printed wiring board 3 and the first terminal forming end E1 of the first base sheet 11 of the substrate 1 to be connected are arranged parallel to each other. In this case, one of the ends in the Y direction of the wide portion 31a protrudes from the end in the Y direction of the first base sheet 11 (that is, the first terminal forming end E1). Thereby, stress concentration at the portion where the first base sheet 11 contacts the end of the second base sheet 31 can be further suppressed.

[0045] Furthermore, as shown in FIG. 4, a small R cut is formed at the connection portion of the wide portion 31a with the second base sheet 31. The dimension of this R cut (the radius of curvature of R) may be, for example, within the range of 0.1 mm to 1.5 mm, and most preferably within the range of 0.3 mm to 1.0 mm. Thereby, large "R cuts" or "C cuts" are not formed at the boundary portion B between the base of the wide portion 31a and the end of the second base sheet 31. In this way, by reducing the "R" provided at the boundary portion B, it is possible to suppress the concentration of stress on the first base sheet 11.

[0046] In the electronic component 100, a plurality of dummy terminals 39 are formed side by side in the X direction in the wide portion 31a of the second base sheet 31. The number of dummy terminals 39 formed can be any number. The dummy terminals 39 are formed of the same material as the second terminals 33, for example, a conductive material such as copper (Cu), silver (Ag), gold (Au), or aluminum (Al). In addition, the dummy terminals 39 can also be composed of a material different from that of the second terminals 33. Note that the "dummy" of the dummy terminals 39 means that it is not used for the purpose of electrically connecting between the electric circuit 13 of the connected substrate 1 and a predetermined device (that is, an external device, an electric circuit formed on the second base sheet 31, etc.). That is, the dummy terminals 39 are not provided with a second wiring pattern 35 for connecting to a predetermined device. For this reason, the wide portion 31a is not provided with a second wiring pattern 35 for connecting the dummy terminals 39 and the predetermined device.

[0047] Also, as shown in FIGS. 3B and 4, the dummy terminals 39 are arranged close to both ends in the Y direction of the wide portion 31a. That is, both ends of the dummy terminals 39 in the Y direction are close to both ends of the wide portion 31a in the Y direction. More specifically, the length of the dummy terminals 39 in the Y direction is close to the length d1 of the wide portion 31a in the Y direction.

[0048] In this way, by not providing the second wiring pattern 35 in the wide portion 31a and arranging the dummy terminals 39 close to both ends in the Y direction of the wide portion 31a, the length d1 in the Y direction of the wide portion 31a can be reduced, so that the ability to disperse the stress acting on the substrate 1 to be connected by the wide portion 31a can be further improved.

[0049] The thickness of the dummy terminal 39 is, for example, about several tens of μm (for example, about 10 μm to 30 μm), and it is preferably larger than 0.5 times the distance between the first base sheet 11 and the second base sheet 31 (wide portion 31a). More preferably, the thickness of the dummy terminal 39 can be about 0.6 to 0.8 times the distance between the first base sheet 11 and the second base sheet 31. For example, when the distance between the first base sheet 11 and the second base sheet 31 is 25 μm, the thickness of the dummy terminal 39 can be 15 μm to 20 μm.

[0050] As described above, by providing a plurality of dummy terminals 39 in the wide portion 31a, when the first base sheet 11 and the second base sheet 31 are fixed by the fixing member 7, the fixing member 7 enters the space between the plurality of dummy terminals 39, and the fixing member 7 is filled between the first base sheet 11 and the wide portion 31a without a gap. As a result, it becomes difficult to form a space such as a bubble in the fixing member 7 between the wide portion 31a and the first base sheet 11, so that the wide portion 31a and the first base sheet 11 can be fixed more firmly.

[0051] It is preferable that the shape and thickness of the dummy terminal 39 are the same as those of the second terminal 33. By making the shape and thickness of the dummy terminal 39 the same as those of the second terminal 33, when the first base sheet 11 and the second base sheet 31 are crimped, the filling state of the fixing member 7 can be made the same in the formation portion of the dummy terminal 39 (wide portion 31a) and the formation portion of the second terminal 33, so that it becomes difficult to form a space such as a bubble in the fixing member 7 of these portions. As a result, the first base sheet 11 and the second base sheet 31 (wide portion 31a) can be fixed more firmly.

[0052] Furthermore, it is preferable that the arrangement intervals in the X direction of the plurality of dummy terminals 39 are the same as the arrangement intervals in the X direction of the plurality of second terminals 33. That is, it is preferable to make the distance between adjacent dummy terminals 39 the same as the distance between adjacent second terminals 33. Also, the arrangement interval between the second terminal 33 provided at the end in the X direction of the second terminal forming end portion E2 and the dummy terminal 39 adjacent to the second terminal 33 is preferably the same as the arrangement interval in the X direction of the plurality of second terminals 33. Thereby, since the fixing states by the fixing member 7 can be made the same between the forming portions of the plurality of second terminals 33 in the second base sheet 31 and the forming portions of the plurality of dummy terminals 39 in the wide portion 31a, the substrate to be connected 1 and the flexible printed wiring board 3 can be fixed uniformly.

[0053] In addition, in the present embodiment, dummy terminals 39' are also provided in a portion of the first base sheet 11 that faces the wide portion 31a so as to correspond to the plurality of dummy terminals 39. In this case, it is preferable that the thickness of the dummy terminals 39' formed on the first base sheet 11 is the same as the thickness of the first terminals 15 formed at the first terminal forming end portion E1 of the first base sheet 11. The thickness of the dummy terminals 39' can be, for example, about several hundred nm. These dummy terminals 39' may be omitted. That is, the dummy terminals 39 may be provided only in the wide portion 31a of the second base sheet 31.

[0054] Conversely, dummy terminals 39' may be provided only at the portion facing the wide portion 31a of the first base sheet 11, and dummy terminals may not be provided on the wide portion 31a of the second base sheet 31. In this case, the thickness of the dummy terminals 39' formed on the first base sheet 11 can be, for example, about several tens of μm (for example, about 10 μm to 30 μm). Also, it is preferable that the thickness of the dummy terminals 39' is greater than 0.5 times the distance between the first base sheet 11 and the second base sheet 31 (wide portion 31a). More preferably, the thickness of the dummy terminals 39' can be about 0.6 to 0.8 times the distance between the first base sheet 11 and the second base sheet 31. For example, when the distance between the first base sheet 11 and the second base sheet 31 is 25 μm, the thickness of the dummy terminals 39' can be set to 15 μm to 20 μm.

[0055] When providing the dummy terminals 39' only at the portion facing the wide portion 31a of the first base sheet 11, it is preferable to make the shape and thickness of the dummy terminals 39' the same as those of the first terminals 15. When providing the dummy terminals 39' only at the portion facing the wide portion 31a of the first base sheet 11, it is preferable to make the thickness of the first terminals 15 approximately the same as that of the dummy terminals 39' (for example, about 10 μm to 30 μm, more preferably, 15 μm to 20 μm).

[0056] When providing the dummy terminals 39' only at the portion facing the wide portion 31a of the first base sheet 11, the thickness of the second terminals 33 provided on the second base sheet 31 where no dummy terminals are provided is preferably set to be less than or equal to half of the thickness of the normal second terminals 33.

[0057] Furthermore, dummy terminals 39 and 39' are provided on both the wide portion 31a of the second base sheet 31 and the portion of the first base sheet 11 facing the wide portion 31a. However, the thickness of the dummy terminal 39' provided on the first base sheet 11 may be made larger than that of the dummy terminal 39 provided on the wide portion 31a. In this case, the thickness of the dummy terminal 39' formed on the first base sheet 11 can be, for example, about several tens of μm (for example, about 10 μm to 30 μm). Also, it is preferable that the thickness of the dummy terminal 39' is larger than 0.5 times the distance between the first base sheet 11 and the second base sheet 31 (wide portion 31a). More preferably, the thickness of the dummy terminal 39' can be about 0.6 to 0.8 times the distance between the first base sheet 11 and the second base sheet 31. On the other hand, the thickness of the dummy terminal 39 provided on the wide portion 31a can be, for example, about several hundreds of nm.

[0058] Also, in the above case, it is preferable that the thickness of the first terminal 15 provided on the first base sheet 11 is the same as the thickness of the dummy terminal 39', and the thickness of the second terminal 33 provided on the second base sheet 31 is the same as the thickness of the dummy terminal 39. For example, the thickness of the first terminal 15 can be about several tens of μm (for example, about 10 μm to 30 μm), and the thickness of the second terminal 33 can be about several hundreds of nm.

[0059] 2. Other Embodiments Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention. In particular, the plurality of embodiments and modifications described in this specification can be arbitrarily combined as needed. (A) In the above first embodiment, the flexible printed wiring board 3 was fixed to the lower side of the substrate 1 to be connected. However, it is not limited to this, and the flexible printed wiring board 3 may be fixed to the upper side of the substrate 1 to be connected. Also in this case, the technology described above can be applied.

[0060] (B) In the above-described first embodiment, only one second terminal forming end portion E2 was provided on the second base sheet 31 of the flexible printed wiring board 3. However, the present invention is not limited to this, and the second base sheet 31 may have a plurality of second terminal forming end portions E2. For example, as shown in FIG. 5A, the second base sheet 31 may have two second terminal forming end portions E2. In this case, one second terminal forming end portion E2 may be fixed to the upper surface of the first base sheet 11 of the substrate 1 to be connected, and the other second terminal forming end portion E2 may be fixed to the lower surface of the first base sheet 11.

[0061] Further, as shown in FIG. 5A, the wide portions 31a are provided only at the outermost portions in the X direction of each second terminal forming end portion E2, rather than at both ends in the X direction. Thereby, since the number of wide portions 31a formed can be minimized, the manufacturing cost of the electronic component 100 (second base sheet 31) can be reduced.

[0062] Furthermore, as shown in FIGS. 5B and 5C, two or more second terminal forming end portions E2 may be provided on the second base sheet 31 of the flexible printed wiring board 3. In the example shown in FIG. 5B, three second terminal forming end portions E2 are provided on the second base sheet 31. In the example shown in FIG. 5C, four second terminal forming end portions E2 are provided on the second base sheet 31.

[0063] In these cases, the second terminal forming end portion E2 existing at the outermost portion in the X direction may be fixed to the upper surface of the first base sheet 11 of the substrate 1 to be connected, and the second terminal forming end portion E2 existing at the central portion may be fixed to the lower surface of the first base sheet 11. Conversely, the second terminal forming end portion E2 existing at the outermost portion in the X direction may be fixed to the lower surface of the first base sheet 11 of the substrate 1 to be connected, and the second terminal forming end portion E2 existing at the central portion may be fixed to the upper surface of the first base sheet 11.

[0064] Further, as shown in FIGS. 5B and 5C, instead of providing the wide portions 31a at both ends in the X direction of each of two or more second terminal forming ends E2, the wide portion 31a may be provided only at the outermost end in the X direction of the second terminal forming end E2 existing at the outermost part in the X direction among the plurality of second terminal forming ends E2. Thereby, since the number of formed wide portions 31a can be minimized, the manufacturing cost of the electronic component 100 due to the increase in the area of the second base sheet 31 can be reduced. FIGS. 5A to 5C are views showing other examples of the electronic component 100.

[0065] (C) In the above-described first embodiment, as shown in FIGS. 2 to 3B, the transparent adhesive portion 51 was provided only on a part of the first base sheet 11 in the Y direction. Specifically, the transparent adhesive portion 51 was provided at one end in the Y direction of the first base sheet 11, but not provided at the first terminal forming end E1. However, it is not limited to this. As shown in FIGS. 6A and 6B, the transparent adhesive portion 51 may be provided on the entire first base sheet 11. FIG. 6A is a cross-sectional view when an end portion of the electronic component 100 of still another example is cut in the X direction. FIG. 6B is a cross-sectional view when the first terminal and the second terminal portions of the electronic component 100 of still another example are cut in the Y direction.

[0066] Even when the transparent adhesive portion 51 is provided on the entire first base sheet 11 as described above, when the flexible printed wiring board 3 is deformed (for example, by a strong force), peeling may occur at the interface between the transparent adhesive portion 51 and the second base sheet 31 or at the interface between the transparent adhesive portion 51 and the cover member 5. When such peeling occurs, the connected substrate 1 may be damaged when the flexible printed wiring board 3 is deformed.

[0067] In this case, similar to the above-described first embodiment, by providing the wide portion 31a at the end in the X direction of the second base sheet 31, the stress acting on the first base sheet 11 of the connected substrate 1 due to the deformation of the flexible printed wiring board 3 can be dispersed, so that damage to the connected substrate 1 can be suppressed.

[0068] (D) The dimensions and / or shape of each part in the electronic component 100 can be appropriately adjusted according to the size, shape, etc. of the product in which the electronic component 100 is incorporated.

[0069] 3. Supplementary Note The above-described embodiments can also be described as follows. (1) An electronic component (for example, the electronic component 100) includes a substrate to be connected (for example, the substrate to be connected 1) and a flexible printed wiring board (for example, the flexible printed wiring board 3). The substrate to be connected has a first base sheet (for example, the first base sheet 11), a predetermined electric circuit (for example, the electric circuit 13) formed on the first base sheet, a first terminal forming end portion (for example, the first terminal forming end portion E1) formed at at least one end of the first base sheet, and a plurality of first terminals (for example, the first terminals 15) formed on the first terminal forming end portion and connected to the electric circuit. The flexible printed wiring board has a second base sheet (for example, the second base sheet 31), a second terminal forming end portion (for example, the second terminal forming end portion E2) formed at at least one end of the second base sheet, and a plurality of second terminals (for example, the second terminals 33) formed on the second terminal forming end portion and connected to the first terminals of the substrate to be connected by a fixing member (for example, the fixing member 7).

[0070] In the above-described electronic component, a wide portion (for example, the wide portion 31a) extending in a first direction (for example, the X direction), which is the direction in which the plurality of second terminals are arranged, is formed at the second terminal forming end portion. Further, dummy terminals (for example, the dummy terminals 39, 39') are formed on at least one of the wide portion and the portion of the first base sheet facing the wide portion.

[0071] In the above-described electronic component, a wide portion extending in a first direction, which is the direction in which a plurality of second terminals are arranged, is provided at the second terminal forming end portion of the second base sheet of the flexible printed wiring board, that is, at the connection portion between the second base sheet and the first base sheet. By providing the wide portion, when the second base sheet is deformed, the stress acting on the first base sheet due to this deformation is dispersed, and the concentration of stress at a specific location of the first base sheet is suppressed. As a result, it is possible to prevent the connected substrate from being damaged due to the deformation of the flexible printed wiring board.

[0072] Also, dummy terminals are formed on at least one of the wide portion and the portion of the first base sheet facing the wide portion. By providing dummy terminals at the wide portion and the portion of the first base sheet corresponding to the wide portion, when the first base sheet and the second base sheet are fixed by a fixing member, the fixing member is more likely to be filled in the wide portion without gaps. As a result, it is less likely to form a space such as a bubble in the fixing member between the wide portion and the first base sheet, so the wide portion and the first base sheet can be fixed more firmly.

[0073] (2) In the electronic component of (1) above, the length in the first direction of the wide portion (for example, length d2) may be 1 time or more the length in a second direction (for example, Y direction) perpendicular to the first direction of the wide portion (for example, length d1). Thereby, when the second base sheet is deformed, the stress acting on the first base sheet can be more effectively dispersed.

[0074] (3) In the electronic component of (1) or (2) above, the first terminal forming end portion of the first base sheet and the second terminal forming end portion of the second base sheet may be arranged parallel to each other. In this case, the end portion in the second direction perpendicular to the first direction of the wide portion may protrude from the end portion of the first base sheet. Thereby, the concentration of stress at a specific location of the first base sheet can be further suppressed.

[0075] (4) In any of the electronic components (1) to (3) above, a wiring pattern for connecting a dummy terminal and a predetermined device may not be provided in the wide portion. As a result, the length of the wide portion in the second direction can be reduced, so that the ability to disperse the stress acting on the substrate to be connected by the wide portion can be improved.

[0076] (5) In any of the electronic components (1) to (4) above, the second base sheet may have a plurality of terminal forming ends. In this case, the wide portion may be provided only at the outermost portion in the width direction of the second base sheet among the plurality of terminal forming ends. Thereby, since the number of wide portions formed can be reduced, the cost of the electronic component due to the increase in the area of the second base sheet can be reduced.

[0077] (6) In any of the electronic components (1) to (5) above, the dummy terminals may be arranged close to both ends in the second direction perpendicular to the first direction of the wide portion. As a result, the length of the wide portion in the second direction can be reduced, so that the ability to disperse the stress acting on the substrate to be connected by the wide portion can be improved.

[0078] (7) In any of the electronic components (1) to (6) above, a plurality of dummy terminals may be provided side by side in the first direction. In this case, the arrangement interval in the first direction of the plurality of dummy terminals may be the same as the arrangement interval in the first direction of the plurality of second terminals. Thereby, since the fixing states of the fixing member at the forming portions of the plurality of second terminals and the forming portions of the plurality of dummy terminals can be made the same, the substrate to be connected and the flexible printed wiring board can be fixed uniformly.

[0079] (8) In any of the electronic components (1) to (7) above, an R cut may be formed at the connection portion of the wide portion with the second base sheet. In this case, the dimension (curvature radius of R) of the R cut may be within the range of 0.1 mm to 1.5 mm, and the range of 0.3 mm to 1.0 mm is most preferable. Thereby, since large C cuts and R cuts are not formed at the boundary portion between the wide portion and the second base sheet, stress concentration at the contact portion of the first base sheet with the boundary portion can be suppressed.

Description of Symbols

[0080] 100: Electronic component 1: Substrate to be connected 11: First base sheet 13: Electric circuit 15: First terminal 3: Flexible printed wiring board 31: Second base sheet 31a: Wide portion 33: Second terminal 35: Second wiring pattern 39, 39’: Dummy terminals 7: Fixing member E1: First terminal forming end E2: Second terminal forming end

Claims

1. A connected substrate having a first base sheet, a predetermined electric circuit formed on the first base sheet, a first terminal forming end portion formed at at least one end of the first base sheet, and a plurality of first terminals formed on the first terminal forming end portion and connected to the electric circuit; A flexible printed wiring board having a second base sheet, a second terminal forming end portion formed at at least one end of the second base sheet, and a plurality of second terminals formed on the second terminal forming end portion and connected to the first terminals of the connected substrate by fixing members; Comprising: A wide portion extending in a first direction, which is a direction in which the plurality of second terminals are arranged, is formed at the second terminal forming end portion; An electronic component in which dummy terminals are formed on at least one of the wide portion and a portion of the first base sheet facing the wide portion.

2. The electronic component according to claim 1, wherein a length of the wide portion in the first direction is 1 time or more of a length of the wide portion in a second direction perpendicular to the first direction.

3. The first terminal forming end portion and the second terminal forming end portion are arranged parallel to each other; The electronic component according to claim 1 or 2, wherein an end portion of the wide portion in a second direction perpendicular to the first direction protrudes from an end portion of the first base sheet.

4. The electronic component according to claim 1 or 2, wherein a wiring pattern for connecting the dummy terminal and a predetermined device is not provided in the wide portion.

5. The second base sheet has a plurality of the terminal forming end portions; The electronic component according to claim 1 or 2, wherein the wide portion is provided only at an outermost portion of the second base sheet in the first direction among the plurality of terminal forming end portions.

6. The electronic component according to claim 1 or 2, wherein the dummy terminals are arranged close to both end portions of the wide portion in a second direction perpendicular to the first direction.

7. A plurality of the dummy terminals are provided side by side in the first direction; The electronic component according to claim 1 or 2, wherein an arrangement interval of the plurality of dummy terminals in the first direction is the same as an arrangement interval of the plurality of second terminals in the first direction.

8. An R cut is formed at a connection portion of the wide portion with the second base sheet; The electronic component according to claim 1 or 2, wherein a dimension of the R cut is in a range of 0.1 mm to 1.5 mm.

Images