Electronic component

Abstract

[Problem] To prevent the breakage of a connection-receiving board. [Solution] An electronic component 100 comprises a connection-receiving board 1 and a flexible printed wiring board 3. The connection-receiving board 1 has a first base sheet 11, an electric circuit 13 which is formed in the first base sheet 11, a first terminal formation part E1 which is formed at least at one end of the first base sheet, and a plurality of first terminals 15 which are formed in the first terminal formation end part E1 and are connected to the electric circuit 13. The flexible printed wiring board 3 has a second base sheet 31, a second terminal formation part E2 which is formed at least at one end of the second base sheet, and a plurality of second terminals 33 which are formed in the second terminal formation end part E2 and are connected to the first terminals 15. In the second terminal formation end part E2, a wide part 31a that extends in the X direction, which is the direction in which the plurality of second terminals 33 are arranged, is formed. Dummy terminals 39, 39' are formed in at least one of the wide part 31a and a part of the first base sheet 11 that faces the wide part 31a.

Description

Electronic Components

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

[0002] Conventionally, electronic components have been known that include a connected substrate on which a predetermined electrical circuit such as a touch sensor is formed, and a flexible printed wiring board for connecting this electrical circuit to an external device (see, for example, Patent Document 1).

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

[0004] JP 2008-98548 A

[0005] In the above electronic component, for example, when the flexible printed wiring board is deformed by being lifted in a direction perpendicular to the connected substrate, the connected substrate may be damaged, particularly at the end of the connected substrate to which the flexible printed wiring board is fixed, near the end of the flexible printed wiring board.

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

[0007] Several aspects are described below as means for solving the problems. These aspects can be combined as needed. 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 provided on at least one end of the first base sheet, and a plurality of first terminals formed on the first terminal-forming end and connected to the electric circuit. The flexible printed wiring board has a second base sheet, a second terminal-forming end provided on at least one end of the second base sheet, and a plurality of second terminals formed on the second terminal-forming end and connected to the first terminals of the substrate to be connected by fixing members.

[0008] In the electronic component according to the first aspect, the second terminal forming end portion has a wide portion extending in a first direction in which the second terminals are arranged, and a dummy terminal is 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 is provided at the second terminal forming end of the second base sheet of the flexible printed wiring board, i.e., at the connection portion between the second base sheet and the first base sheet, extending in a first direction, which is the direction in which the plurality of second terminals are arranged. By providing the wide portion, when the second base sheet deforms, the stress acting on the first base sheet due to this deformation is dispersed, and stress concentration at a specific location on the first base sheet is suppressed. As a result, damage to the connected substrate due to deformation of the flexible printed wiring board can be suppressed.

[0010] Furthermore, 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 on 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 with a fixing member, the fixing member is more likely to fill the wide portion without gaps. As a result, air bubbles and other voids are less likely to form in the fixing member between the wide portion and the first base sheet, and 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 at least one time the length of the wide portion in a second direction perpendicular to the first direction, thereby enabling better distribution of stress acting on the first base sheet when the second base sheet deforms.

[0012] In the electronic component according to the third aspect, the first terminal-forming end of the first base sheet and the second terminal-forming end of the second base sheet may be arranged parallel to each other. In this case, the end of the wide portion in a second direction perpendicular to the first direction may extend beyond the end of the first base sheet. This further prevents stress from concentrating at a specific location on the first base sheet.

[0013] In the electronic component according to the fourth aspect, the wide portion does not need to be provided with a wiring pattern for connecting the dummy terminal and a predetermined device, which allows the length of the wide portion in the second direction to be reduced, thereby improving the ability of the wide portion to distribute stress acting on the connected board.

[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 portions may be provided only at the outermost portions of the plurality of terminal forming end portions in the first direction of the second base sheet. This reduces the number of wide portions formed, thereby reducing the cost of the electronic component due to the increased area of ​​the second base sheet.

[0015] In the electronic component according to the sixth aspect, the dummy terminals may be disposed adjacent to both ends of the wide portion in a second direction perpendicular to the first direction, thereby reducing the length of the wide portion in the second direction and improving the ability of the wide portion to distribute stress acting on the connected board.

[0016] In the electronic component according to the seventh aspect, the dummy terminals may be arranged in a plurality of rows in the first direction. In this case, the spacing between the dummy terminals in the first direction may be the same as the spacing between the second terminals in the first direction. This allows the fixed state by the fixing member to be the same between the portion where the second terminals are formed and the portion where the dummy terminals are formed, thereby enabling the connected substrate and the flexible printed wiring board to be fixed uniformly.

[0017] In the electronic component according to the eighth aspect, the wide portion may have an R-cut formed at the connection portion with the second base sheet. In this case, the dimension of the R-cut (the radius of curvature of the R) may be within a range of 0.1 mm to 1.5 mm, and most preferably within a range of 0.3 mm to 1.0 mm. This prevents a large C-cut or R-cut from being formed at the boundary portion between the wide portion and the second base sheet, thereby reducing the length of the wide portion in the second direction and improving the ability of the wide portion to distribute stress acting on the connected board.

[0018] By providing a wide portion at the second terminal forming end of the second base sheet of the flexible printed wiring board, it is possible to prevent large stress from being generated in the first base sheet of the connected substrate when the second base sheet of the flexible printed wiring board is deformed, thereby preventing damage to the connected substrate.

[0019] 1 is a perspective view of an electronic component; 2 is a cross-sectional view of an end of the electronic component cut in the X direction; 3 is a cross-sectional view of a first terminal and a second terminal portion of the electronic component cut in the Y direction; 4 is a cross-sectional view of a wide portion and a dummy terminal portion of the electronic component cut in the Y direction; 5 is an enlarged plan view of the vicinity of a terminal-forming end portion of the electronic component; 6 is a view (part 1) showing another example of an electronic component; 7 is a view (part 2) showing another example of an electronic component; 8 is a view (part 3) showing another example of an electronic component; 9 is a cross-sectional view of an end of yet another example of an electronic component cut in the X direction; 10 is a cross-sectional view of a first terminal and a second terminal portion of yet another example of an electronic component cut in the Y direction.

[0020] 1. First Embodiment An electronic component 100 according to this embodiment will now 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 of an end of the electronic component 100 cut in the X direction. FIG. 3A is a cross-sectional view of the first and second terminal portions of the electronic component 100 cut in the Y direction. FIG. 3B is a cross-sectional view of the wide portion and dummy terminal portions of the electronic component 100 cut in the Y direction. FIG. 4 is an enlarged plan view of the vicinity of the terminal-forming end portion 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 connected substrate 1 and a flexible printed wiring board 3.

[0021] The connected substrate 1 is a flexible substrate on which a predetermined electric circuit is formed. The connected substrate 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 made of a flexible material (e.g., a resin material or a plastic material). The first base sheet 11 is a plate-like member made of, for example, 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 contact of a contact member, such as a finger, on the surface. The electric circuit 13 is, for example, a capacitive touch sensor or a resistive touch sensor. 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 console, or a touch screen.

[0023] The first terminals 15 are arranged in the X direction, which is the direction in which the first terminals 15 are arranged, at an end (referred to as a first-terminal-forming end E1) in the Y direction (length direction) on the first base sheet 11. The number of first terminals 15 can be determined appropriately depending on the type of electric circuit 13, etc. The first terminals 15 are connected to the electric circuit 13 via the first wiring pattern 17. The first terminals 15 are electrically connected to the second terminals 33 of the flexible printed wiring board 3. That is, the first terminals 15 are terminals for electrically connecting the electric circuit 13 to a predetermined device (e.g., an external device provided separately from the connected substrate 1 and the flexible printed wiring board 3, an electric circuit (e.g., 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 terminals 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 nanometers.

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

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

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

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

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

[0029] The second terminal 33 is connected to a predetermined device via the second wiring pattern 35. The predetermined device is, for example, an external device provided separately from the connected substrate 1 and the flexible printed wiring board 3, and / or an electrical circuit (e.g., a control circuit that controls the electrical circuit 13 of the connected substrate 1) formed on the second base sheet 31 of the flexible printed wiring board 3. The second terminal 33 is electrically connected to the first terminal 15 of the connected substrate 1. That is, the second terminal 33 is a terminal for electrically connecting the electrical circuit 13 of the connected substrate 1 to the 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). The thickness of the second terminal 33 is, for example, approximately several tens of μm (e.g., approximately 10 μm to 30 μm).

[0030] 3A , the second wiring pattern 35 is protected by a 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, or the like.

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

[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 that imparts 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 is a member that imparts conductivity only between the terminals that are crimped together with the anisotropic conductive paste sandwiched therebetween (i.e., between the first terminal 15 and the second terminal 33). The binder resin is, for example, an epoxy resin or an acrylic resin. The conductive particles include, for example, metal, metal alloy, metal oxide, carbon, and graphite particles, as well as insulating particles coated with a metal. Metals used for the conductive particles include, for example, 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 sandwiched between the first base sheet 11 and the second base sheet 31 and then compressed (press-bonded) between the first base sheet 11 and the second base sheet 31. This allows the anisotropic conductive member to fill the spaces between the multiple second terminals 33, filling the space between the first base sheet 11 and the second base sheet 31 without leaving any gaps. As a result, spaces such as air bubbles are less likely to form within the fixing member 7 between the first base sheet 11 and the second base sheet 31, allowing the first base sheet 11 and the second base sheet 31 to be fixed more firmly.

[0034] Furthermore, the first terminal 15 and the second terminal 33 are electrically connected by the conductive particles contained in the anisotropic conductive material between the first terminal 15 and the second terminal 33. On the other hand, in areas where the first terminal 15 and the second terminal 33 are not present, the anisotropic conductive material is solidified with the conductive particles dispersed, so that the conductive particles do not form a path for current to flow. In other words, the areas where the first terminal 15 and the second terminal 33 are not present are essentially insulators.

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

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

[0037] Therefore, in the electronic component 100, a wide portion 31a is provided at the X-direction (width direction) end of the second terminal forming end E2 of the second base sheet 31, extending from the end in the X-direction, which is the direction in which the multiple second terminals 33 are arranged, and the wide portion 31a is fixed to the first terminal forming end 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 the plurality of second terminals 33 are arranged, at the end of the second terminal forming end E2 of the second base sheet 31, i.e., 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 deforms, the stress acting on the first base sheet 11 of the connected substrate 1 due to this deformation is dispersed, and stress concentration at a predetermined location of the first base sheet 11 (for example, a portion in contact with the end of the second base sheet 31) is suppressed. As a result, damage to the first base sheet 11 of the connected substrate 1 due to deformation of the flexible printed wiring board 3 can be suppressed.

[0039] The smaller the width (length d1 in the Y direction) of the wide portion 31a, the greater the ability of the wide portion 31a to disperse the stress acting on the first base sheet 11. In other words, 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 (e.g., about 2 to 3 mm).

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

[0041] It has also been found that the ability of the wide portion 31a to disperse the stress acting on the first base sheet 11 increases as the length of the wide portion 31a (length d2 in the X direction) increases. In other words, it is preferable that the length d2 of the wide portion 31a is large.

[0042] To demonstrate this, we varied the length d2 of the wide portion 31a to determine the degree of tensile force that the flexible printed wiring board 3 could withstand when pulling and lifting the first base sheet 11. As a result, when the length (length d2 in the X direction) of the wide portion 31a was set to be approximately the same as the width (length d1 in the Y direction) of the wide portion 31a (i.e., d2 / d1≈1), the first base sheet 11 was able to withstand a tensile force approximately twice as strong as the tensile force that broke the first base sheet when the wide portion 31a was not provided (i.e., d2 = 0). Furthermore, when the length of the wide portion 31a was set to be approximately twice the width of the wide portion 31a (i.e., d2 / d1≈2), the first base sheet 11 was able to withstand a tensile force approximately three times stronger than the tensile force that broke the first base sheet when the wide portion 31a was not provided.

[0043] In this way, by making the X-direction length d2 of the wide portion 31a at least one time the Y-direction length d1 of the wide portion 31a, the stress acting on the first base sheet 11 of the connected substrate 1 can be more effectively distributed when the second base sheet 31 of the flexible printed wiring board 3 is deformed.

[0044] 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 connected substrate 1 are arranged parallel to each other. In this case, one of the Y-direction ends of the wide portion 31a protrudes from the Y-direction end of the first base sheet 11 (i.e., the first terminal forming end E1). This further prevents stress from concentrating in the portion of the first base sheet 11 that contacts the end of the second base sheet 31.

[0045] Furthermore, as shown in Figure 4, the wide portion 31a has a small R-cut formed at the connection with the second base sheet 31. The dimension of this R-cut (the radius of curvature of R) may be, for example, within a range of 0.1 mm to 1.5 mm, and is most preferably within a range of 0.3 mm to 1.0 mm. This prevents a large "R-cut" or "C-cut" from being formed at the boundary portion B between the base of the wide portion 31a and the end of the second base sheet 31. By reducing the "R" at the boundary portion B in this way, stress concentration on the first base sheet 11 can be suppressed.

[0046] In the electronic component 100, a plurality of dummy terminals 39 are formed in the wide portion 31a of the second base sheet 31, aligned in the X direction. The number of dummy terminals 39 can be any number. The dummy terminals 39 are formed of the same material as the second terminals 33, such as a conductive material such as copper (Cu), silver (Ag), gold (Au), or aluminum (Al). Alternatively, the dummy terminals 39 can be formed of a material different from that of the second terminals 33. The "dummy" in the dummy terminals 39 means that they are not used to electrically connect the electrical circuit 13 of the connected substrate 1 to a predetermined device (i.e., an external device, an electrical circuit formed on the second base sheet 31, etc.). In other words, the dummy terminals 39 do not have a second wiring pattern 35 for connecting to the predetermined device. Therefore, the wide portion 31a does not have a second wiring pattern 35 for connecting the dummy terminals 39 to the predetermined device.

[0047] 3B and 4, the dummy terminals 39 are disposed close to both ends of the wide portion 31a in the Y direction. 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. In other words, 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 by arranging the dummy terminal 39 close to both ends of the wide portion 31a in the Y direction, the length d1 in the Y direction of the wide portion 31a can be reduced, thereby further improving the ability of the wide portion 31a to distribute the stress acting on the connected substrate 1.

[0049] The thickness of the dummy terminals 39 is, for example, about several tens of μm (e.g., about 10 μm to 30 μm), and is preferably greater than 0.5 times the distance between the first base sheet 11 and the second base sheet 31 (wide portion 31 a). 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 15 μm to 20 μm.

[0050] As described above, by providing a plurality of dummy terminals 39 on the wide portion 31a, when the first base sheet 11 and the second base sheet 31 are fixed together with the fixing member 7, the fixing member 7 enters into the spaces between the plurality of dummy terminals 39, filling the space between the first base sheet 11 and the wide portion 31a without leaving any gaps. As a result, spaces such as air bubbles are less likely to form within the fixing member 7 between the wide portion 31a and the first base sheet 11, and the wide portion 31a and the first base sheet 11 can be fixed together more firmly.

[0051] The shape and thickness of the dummy terminals 39 are preferably the same as those of the second terminals 33. By making the shape and thickness of the dummy terminals 39 the same as those of the second terminals 33, when the first base sheet 11 and the second base sheet 31 are crimped together, the filling state of the fixing member 7 can be the same in the portions where the dummy terminals 39 are formed (wide portions 31 a) and the portions where the second terminals 33 are formed, making it less likely that air bubbles or other voids will form within the fixing member 7 in these portions. As a result, the first base sheet 11 and the second base sheet 31 (wide portions 31 a) can be more firmly fixed together.

[0052] Furthermore, the arrangement interval between the plurality of dummy terminals 39 in the X direction is preferably the same as the arrangement interval between the plurality of second terminals 33 in the X direction. That is, the distance between adjacent dummy terminals 39 is preferably the same as the distance between adjacent second terminals 33. Also, the arrangement interval between a second terminal 33 provided at an end of the second terminal forming end E2 in the X direction and a dummy terminal 39 adjacent to that second terminal 33 is preferably the same as the arrangement interval between the plurality of second terminals 33 in the X direction. This allows the fixed state by the fixing member 7 to be the same between the portion of the second base sheet 31 where the plurality of second terminals 33 are formed and the portion of the wide portion 31 a where the plurality of dummy terminals 39 are formed, thereby enabling the connected substrate 1 and the flexible printed wiring board 3 to be fixed uniformly.

[0053] In this embodiment, dummy terminals 39' are also provided in a portion of the first base sheet 11 facing the wide portion 31a, corresponding to the plurality of dummy terminals 39. In this case, the thickness of the dummy terminals 39' formed on the first base sheet 11 is preferably the same as the thickness of the first terminals 15 formed on the first terminal forming end portion E1 of the first base sheet 11. The thickness of the dummy terminals 39' can be, for example, approximately several hundred nanometers. This dummy terminal 39' may be omitted. In other words, the dummy terminals 39 may be provided only on the wide portion 31a of the second base sheet 31.

[0054] Conversely, the dummy terminals 39' may be provided only in the portions of the first base sheet 11 facing the wide portion 31a, and no dummy terminals may be provided in 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 may be, for example, several tens of micrometers (e.g., approximately 10 μm to 30 μm). The thickness of the dummy terminals 39' is preferably 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' may be approximately 0.6 to 0.8 times the distance between the first base sheet 11 and the second base sheet 31. For example, if the distance between the first base sheet 11 and the second base sheet 31 is 25 μm, the thickness of the dummy terminals 39' may be 15 μm to 20 μm.

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

[0056] When the dummy terminal 39' is provided only in the portion opposite the wide portion 31a of the first base sheet 11, it is preferable that the thickness of the second terminal 33 provided on the second base sheet 31 on which the dummy terminal is not provided be less than half the thickness of the normal second terminal 33.

[0057] Furthermore, dummy terminals 39, 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. The thickness of the dummy terminals 39' provided on the first base sheet 11 may be greater than the thickness of the dummy terminals 39 provided on the wide portion 31a. In this case, the thickness of the dummy terminals 39' formed on the first base sheet 11 may be, for example, several tens of μm (e.g., approximately 10 μm to 30 μm). The thickness of the dummy terminals 39' is preferably 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' may be approximately 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 set to, for example, about several hundred nanometers.

[0058] In the above case, it is preferable that the thickness of the first terminals 15 provided on the first base sheet 11 is the same as the thickness of the dummy terminals 39′, and that the thickness of the second terminals 33 provided on the second base sheet 31 is the same as the thickness of the dummy terminals 39. For example, the thickness of the first terminals 15 can be set to about several tens of μm (e.g., about 10 μm to 30 μm), and the thickness of the second terminals 33 can be set to about several hundred 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 spirit of the invention. In particular, the multiple embodiments and modifications described in this specification can be arbitrarily combined as needed. (A) In the first embodiment described above, the flexible printed wiring board 3 was fixed to the underside of the connected substrate 1. However, this is not limited to this, and the flexible printed wiring board 3 may also be fixed to the upper side of the connected substrate 1. In this case, the technology described above can also be applied.

[0060] (B) In the first embodiment described above, only one second terminal-forming end portion E2 was provided on the second base sheet 31 of the flexible printed wiring board 3. However, this is not limited to this, and the second base sheet 31 may have multiple 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 connected substrate 1, and the other second terminal-forming end portion E2 may be fixed to the lower surface of the first base sheet 11.

[0061] 5A , wide portions 31 a 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 of each second terminal-forming end portion E2, which minimizes the number of wide portions 31 a formed, thereby reducing the manufacturing cost of electronic component 100 (second base sheet 31).

[0062] 5B and 5C, two or more second terminal forming ends 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 ends E2 are provided on the second base sheet 31. In the example shown in Fig. 5C, four second terminal forming ends E2 are provided on the second base sheet 31.

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

[0064] 5B and 5C, instead of providing wide portions 31a at both X-direction ends of two or more second terminal-forming end portions E2, wide portions 31a may be provided only at the outermost X-direction end portions of the second terminal-forming end portions E2 that are located at the outermost X-direction ends of the multiple second terminal-forming end portions E2. This minimizes the number of wide portions 31a formed, thereby reducing the manufacturing cost of electronic component 100 due to the increased area of ​​second base sheet 31. FIGS. 5A to 5C are diagrams showing other examples of electronic component 100.

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

[0066] Even when the transparent adhesive portion 51 is provided over 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. If such peeling occurs, there is a possibility that the connected substrate 1 may be damaged when the flexible printed wiring board 3 is deformed.

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

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

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

[0070] In the electronic component, the second terminal forming end portion has a wide portion (e.g., wide portion 31a) extending in a first direction (e.g., X direction) in which the plurality of second terminals are arranged. Also, dummy terminals (e.g., dummy terminals 39, 39′) are formed on at least one of the wide portion and a portion of the first base sheet facing the wide portion.

[0071] In the electronic component, a wide portion extending in a first direction, which is the direction in which the plurality of second terminals are arranged, is provided at the second terminal forming end of the second base sheet of the flexible printed wiring board, i.e., the connection portion between the second base sheet and the first base sheet. By providing the wide portion, when the second base sheet deforms, the stress acting on the first base sheet due to this deformation is dispersed, and stress concentration at a specific location on the first base sheet is suppressed. As a result, damage to the connected substrate due to deformation of the flexible printed wiring board can be suppressed.

[0072] Furthermore, 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 on 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 with a fixing member, the fixing member is more likely to fill the wide portion without gaps. As a result, air bubbles and other voids are less likely to form in the fixing member between the wide portion and the first base sheet, and the wide portion and the first base sheet can be fixed more firmly.

[0073] (2) In the electronic component of (1), the length of the wide portion in the first direction (e.g., length d2) may be equal to or greater than one time the length of the wide portion in a second direction (e.g., Y direction) perpendicular to the first direction (e.g., length d1). This allows for better distribution of stress acting on the first base sheet when the second base sheet is deformed.

[0074] (3) In the electronic component of (1) or (2), the first terminal-forming end of the first base sheet and the second terminal-forming end of the second base sheet may be arranged parallel to each other. In this case, the end of the wide portion in a second direction perpendicular to the first direction may extend beyond the end of the first base sheet. This further prevents stress from concentrating at a specific location on the first base sheet.

[0075] (4) In any of the electronic components described in (1) to (3), the wide portion may not be provided with a wiring pattern for connecting the dummy terminal to a predetermined device, thereby reducing the length of the wide portion in the second direction and improving the ability of the wide portion to distribute stress acting on the connected board.

[0076] (5) In any of the electronic components described in (1) to (4), the second base sheet may have a plurality of terminal-forming end portions. In this case, the wide portions may be provided only at the outermost portions of the plurality of terminal-forming end portions in the width direction of the second base sheet. This reduces the number of wide portions, thereby reducing the cost of the electronic component due to the increased area of ​​the second base sheet.

[0077] (6) In any of the electronic components described in (1) to (5), the dummy terminals may be disposed adjacent to both ends of the wide portion in a second direction perpendicular to the first direction, thereby reducing the length of the wide portion in the second direction and improving the ability of the wide portion to distribute stress acting on the connected board.

[0078] (7) In any of the electronic components described in (1) to (6), the dummy terminals may be arranged in a plurality of rows in a first direction. In this case, the spacing between the dummy terminals in the first direction may be the same as the spacing between the second terminals in the first direction. This allows the fixed state by the fixing member to be the same between the portion where the second terminals are formed and the portion where the dummy terminals are formed, thereby enabling the connected substrate and the flexible printed wiring board to be fixed uniformly.

[0079] (8) In any of the electronic components described in (1) to (7) above, the wide portion may have an R-cut at the connection with the second base sheet. In this case, the dimension of the R-cut (the radius of curvature of the R) may be within a range of 0.1 mm to 1.5 mm, and most preferably within a range of 0.3 mm to 1.0 mm. This prevents a large C-cut or R-cut from being formed at the boundary between the wide portion and the second base sheet, thereby suppressing stress concentration at the contact portion of the first base sheet with the boundary.

[0080] 100: Electronic component 1: Connected substrate 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 terminal 7: Fixing member E1: First terminal forming end E2: Second terminal forming end

Claims

1. An electronic component comprising: a first base sheet, a connected substrate having a predetermined electric circuit formed on the first base sheet, a first terminal forming end formed on at least one end of the first base sheet, and a plurality of first terminals formed on the first terminal forming end and connected to the electric circuit; and a flexible printed wiring board having a second base sheet, a second terminal forming end formed on at least one end of the second base sheet, and a plurality of second terminals formed on the second terminal forming end and connected to first terminals of the connected substrate by a fixing member, wherein the second terminal forming end has a wide portion formed therein extending in a first direction which is a direction in which the plurality of second terminals are arranged, and a dummy terminal is 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 the length of said wide portion in said first direction is at least one time the length of said wide portion in a second direction perpendicular to said first direction.

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

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

5. An electronic component as described in claim 1 or 2, wherein the second base sheet has a plurality of the terminal forming ends, and the wide portion is provided only at the outermost portion of the plurality of terminal forming ends in the first direction of the second base sheet.

6. The electronic component according to claim 1 or 2, wherein the dummy terminals are disposed adjacent to both ends of the wide portion in a second direction perpendicular to the first direction.

7. The electronic component according to claim 1 or 2, wherein the dummy terminals are arranged in a row in the first direction, and the spacing between the dummy terminals in the first direction is the same as the spacing between the second terminals in the first direction.

8. The electronic component according to claim 1 or 2, wherein an R-cut is formed in the connection portion between the wide portion and the second base sheet, and the dimension of the R-cut is within the range of 0.1 mm to 1.5 mm.

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