Film circuit board

Abstract

A thin film circuit board comprises a first substrate, a second substrate, a spacing layer and a conductive adhesive. The first substrate comprises a plurality of first butt joint circuits and at least one first transmission circuit. The first transmission circuit is connected to one of the plurality of first docking circuits. The second substrate includes a plurality of second docking circuits respectively corresponding to the plurality of first docking circuits. The spacer layer is disposed between the first substrate and the second substrate. The spacing layer comprises a butt joint opening and at least one first stress weakening part. One end of the first stress weakening part is connected to the butt joint opening, and the first stress weakening part corresponds to the first transmission circuit. The conductive adhesive is arranged in the butt joint opening and is in contact with the first butt joint circuit and the second butt joint circuit.

Description

Technical Field

[0001] The invention relates to a thin film circuit board. Background Art

[0002] With the advancement of technology, most electronic products are developing towards the design concept of light, thin, short and small. For example, keyboards have also changed from the early large-scale structure to thin keyboards. Thin keyboards usually use multi-layer film circuit boards.

[0003] Figure 1A It is a partial top view of a conventional thin film circuit board. Figure 1B for Figure 1A The cross-sectional view of the thin film circuit board shown in FIG. Figure 1C For hot pressing head Figure 1B For the schematic diagram of the film circuit board lamination shown in Figure 1A , Figure 1B and Figure 1C As shown. The multi-layer film circuit board 9 includes an upper film 91, a middle spacer 92 and a lower film 93 stacked in sequence. Among them, the upper film 91 has an upper circuit 911, and the lower film 93 has a lower circuit 931. The upper circuit 911 and the lower circuit 931 have overlapping and docking parts. The middle spacer 92 has a docking hole 921, and the docking part of the upper circuit 911 and the lower circuit 931 is located in the docking hole 921. In addition, a conductive glue 94 is also provided between the docking parts, and the docking part of the upper circuit 911 and the lower circuit 931 can be pressed by a hot pressing head 8, as shown in FIG. Figure 1B shown.

[0004] Since the current trend of electronic products is miniaturization, the range of the docking hole 921 that can be formed by the middle partition 92 is very small. Taking a thin keyboard as an example, the middle partition 92 must also leave a structural hole for the hook of the bottom plate to pass through, thereby compressing the area where the docking hole 921 can be formed. However, if the area of ​​the docking hole 921 is small, the extended part of the upper circuit 911 or the lower circuit 931 (i.e., the non-docked part) may be broken by the downward pressure of the thermal press head 8 and the shear force between the middle partition 92 (such as Figure 1C If the upper circuit 911 or the lower circuit 931 is broken, the entire thin film circuit board 9 cannot be used, which means that the production yield rate will be reduced, and there is a need for improvement. Summary of the invention

[0005] In view of the above problems, the main purpose of the present invention is to provide a thin film circuit board, which solves the problem that the circuit of the conventional thin film circuit board is easily broken due to pressing through the design of the stress weakening part.

[0006] To achieve the above-mentioned purpose, the present invention provides a thin film circuit board, which includes a first substrate, a second substrate, a spacer layer and a conductive glue. The first substrate includes a plurality of first docking circuits and at least one first transmission circuit. The first transmission circuit is connected to one of the plurality of first docking circuits. The second substrate includes a plurality of second docking circuits, which correspond to the plurality of first docking circuits respectively. The spacer layer is arranged between the first substrate and the second substrate. The spacer layer includes a docking opening and at least one first stress weakening portion. One end of the first stress weakening portion is connected to the docking opening, and the first stress weakening portion corresponds to the first transmission circuit. The conductive glue is arranged in the docking opening and contacts the first docking circuit and the second docking circuit respectively.

[0007] According to an embodiment of the present invention, the thin film circuit board further comprises a pressing reference area, which is distributed in the butting opening and has an area greater than an area of ​​a surface of the conductive adhesive.

[0008] According to an embodiment of the present invention, one end of the pressing reference area is projected onto a bottom surface of the first transmission circuit as a first projection point, and a bottom inner wall of the first stress weakening portion is projected onto a top surface of the first transmission circuit as a second projection point. The slope of the line between the first projection point and the second projection point is less than or equal to 0.0245.

[0009] According to an embodiment of the present invention, a distance from an end of the pressing reference area facing the first stress weakening portion to an inner wall of a bottom side of the first stress weakening portion is greater than or equal to 1.25 mm.

[0010] According to an embodiment of the present invention, the first stress weakening portion is an opening extending outward from one end of the docking opening.

[0011] According to an embodiment of the present invention, the first stress weakening portion accommodates a portion of the pressed conductive adhesive.

[0012] According to an embodiment of the present invention, the first substrate includes a plurality of first transmission circuits, and the spacer layer includes a plurality of first stress weakening portions, each of which corresponds to each first transmission circuit.

[0013] According to an embodiment of the present invention, the first substrate includes a plurality of first transmission circuits, and the first stress weakening portion corresponds to the first transmission circuits.

[0014] According to an embodiment of the present invention, the first substrate further includes at least one second stress weakening portion, which is close to an end of the plurality of first connecting circuits opposite to the first transmission circuit.

[0015] According to an embodiment of the present invention, the second stress weakening portion is an open structure, so that an end of the first connecting circuit adjacent to the second stress weakening portion forms a free end structure.

[0016] According to an embodiment of the present invention, the second substrate further includes at least one third stress weakening portion, which is adjacent to one end of the second docking circuit and corresponds to a portion of the first transmission circuit.

[0017] As described above, the thin film circuit board according to the present invention includes a first substrate, a second substrate, a spacer layer and a conductive adhesive. The spacer layer is arranged between the first substrate and the second substrate. The conductive adhesive is arranged in the docking opening of the spacer layer and contacts the first docking circuit of the first substrate and the second docking circuit of the second substrate respectively. The deformation amount of the first substrate and its first transmission circuit is increased by the structure that the spacer layer has a first stress weakening portion, the first substrate has a second stress weakening portion, or the second substrate has a third stress weakening portion. Therefore, when the hot pressing head presses down the first substrate, the deformation amount of the first transmission circuit is increased by the structure of the aforementioned (first, second or third) stress weakening portion, thereby making the pressure on the first transmission circuit more uniform, so as to achieve the effect of preventing the first transmission circuit from breaking during the pressing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1A It is a partial top view of a conventional thin film circuit board;

[0019] Figure 1B for Figure 1A The schematic cross-sectional view of the thin film circuit board shown at line AA;

[0020] Figure 1C For hot pressing head Figure 1B The schematic diagram of the thin film circuit board being pressed together is shown;

[0021] Figure 2 A partial top view of a thin film circuit board according to a first embodiment of the present invention;

[0022] Figure 3 for Figure 2 A three-dimensional schematic diagram of a thin film circuit board and a thermal pressing head is shown;

[0023] Figure 4 for Figure 3 The exploded diagram of the thin film circuit board and the thermal pressing head shown;

[0024] Figure 5A for Figure 2 The schematic cross-sectional view of the thin film circuit board shown at line BB;

[0025] Figure 5B For hot pressing head Figure 5A The schematic diagram of the film circuit board lamination shown;

[0026] Figure 6 for Figure 5B An enlarged schematic diagram of region C is shown;

[0027] Figure 7 A partial top view of a thin film circuit board according to a second embodiment of the present invention;

[0028] Figure 8 A partial top view of a thin film circuit board according to a third embodiment of the present invention;

[0029] Fig. 9A is a cross-sectional schematic diagram of a thin film circuit board according to a fourth embodiment of the present invention;

[0030] Fig. 9B For hot pressing head Fig. 9A The schematic diagram of the film circuit board lamination shown;

[0031] Fig.10 FIG. 4 is a cross-sectional schematic diagram of a thin film circuit board according to a fifth embodiment of the present invention.

[0032]

Explanation of symbols

[0033] Thin film circuit board 1, 1a, 1b, 1c, 1d, 9

[0034] First substrate 10, 10c

[0035] First docking circuit 11, 11c

[0036] First transmission circuit 12, 12c

[0037] The first projection point 121

[0038] The second projection point 122

[0039] Second stress weakening portion 13c

[0040] Second substrates 20, 20d

[0041] Second docking circuit 21, 21d

[0042] The second transmission circuit 22

[0043] The third stress weakening portion 23d

[0044] Spacer layers 30, 30a, 30b

[0045] Docking openings 31, 31a, 31b

[0046] First stress weakening portions 32, 32a, 32b

[0047] Bottom inner wall 321

[0048] Conductive adhesive 40, 94

[0049] Thermal head 8

[0050] Upper film 91

[0051] Upper circuit 911

[0052] Middle partition 92

[0053] Docking hole 921

[0054] Lower film 93

[0055] Lower circuit 931

[0056] AA Line

[0057] BBB line

[0058] Length L1, L2, L3

[0059] Slope m

[0060] Pressing reference area R DETAILED DESCRIPTION

[0061] In order to better understand the technical content of the present invention, preferred specific embodiments are described below.

[0062] Figure 2 is a partial top view of a thin film circuit board according to a first embodiment of the present invention, Figure 3 for Figure 2 The three-dimensional schematic diagram of the thin film circuit board and a thermal pressing head is shown. Figure 4 for Figure 3 Please refer to the exploded diagram of the film circuit board and the thermal press head shown in Figure 2 , Figure 3 and Figure 4 The thin film circuit board 1 of this embodiment is a thin film circuit board (or thin film switch circuit board) with a three-layer structure, which includes a first substrate 10, a second substrate 20, a spacer layer 30 and a conductive adhesive 40. The first substrate 10 is a thin film circuit board for the hot pressing head 8 to press. Figure 4 For example, the three-layer structure of the thin film circuit board 1 is a first substrate 10, a spacer layer 30, and a second substrate 20 from top to bottom. In other words, the first substrate 10 of this embodiment is an upper thin film circuit board, and the second substrate 20 corresponds to the lower thin film circuit board. In other embodiments, the first substrate 10 and the second substrate 20 can also be configured in the opposite manner. It should also be noted that since the first substrate 10, the second substrate 20 and the spacer layer 30 are a stacked three-layer structure, Figure 2 Marked in the same place.

[0063] The surfaces corresponding to the first substrate 10 and the second substrate 20 respectively have conductive circuits (for example, circuits configured with silver paste lines). In the present embodiment, the overlapping and dockable parts are referred to as docking circuits, and the other extended circuit traces are referred to as transmission circuits. Specifically, the first substrate 10 of the present embodiment includes a plurality of first docking circuits 11 and at least one first transmission circuit 12. In the present embodiment, the first substrate 10 includes a plurality of first transmission circuits 12, each of which is connected to one of the first docking circuits 11. That is, part of the first docking circuits 11 extends outward with the first transmission circuit 12. Correspondingly, the second substrate 20 includes a plurality of second docking circuits 21, which respectively correspond to the plurality of first docking circuits 11. Furthermore, the second substrate 20 may also include a plurality of second transmission circuits 22, which are respectively connected to one of the second docking circuits 21. It should be noted that the first docking circuit 11 and the first transmission circuit 12 are located on the lower surface of the first substrate 10 to correspond to the second substrate 20. In order to clearly indicate the first docking circuit 11, the first transmission circuit 12 and other components located below the first substrate 10, Figure 2 , Figure 3 and Figure 4 The first substrate 10 is indicated by a dotted line. In addition, since the first docking circuit 11 and the second docking circuit 21 overlap each other, Figure 2 Marked in the same place.

[0064] The spacer layer 30 is disposed between the first substrate 10 and the second substrate 20. The spacer layer 30 includes a docking opening 31. The first docking circuit 11 and the second docking circuit 21 are located in the docking opening 31 to correspond to each other. Figure 3 and Figure 4 As shown, a conductive adhesive 40 is disposed between the first docking circuit 11 and the second docking circuit 21. In other words, the conductive adhesive 40 is also disposed in the docking opening 31 and is in contact with the first docking circuit 11 and the second docking circuit 21, respectively. The conductive adhesive 40 of this embodiment may be an anisotropic conductive film (ACF).

[0065] Furthermore, the spacer layer 30 also includes at least one first stress weakening portion 32. One end of the first stress weakening portion 32 is connected to the docking opening 31, and the first stress weakening portion 32 corresponds to the first transmission circuit 12. Specifically, the first stress weakening portion 32 may be, for example but not limited to, a thinned groove or a hollowed-out opening, which provides a deformation space for the first substrate 10 when it is pressed. The first stress weakening portion 32 of the present embodiment is a hollowed-out opening design. Furthermore, the position of the first stress weakening portion 32 corresponds to the first transmission circuit 12. Specifically, the first transmission circuit 12 is hollowed out to form the first stress weakening portion 32 corresponding to the position of the spacer layer 30, and one end of the first stress weakening portion 32 is connected to the docking opening 31, so that the docking opening 31 and the first stress weakening portion 32 form an opening that is interconnected. In other words, the first stress weakening portion 32 is an opening that extends outward from one end of the docking opening 31. In the present embodiment, one first stress weakening portion 32 may correspond to multiple first transmission circuits 12. As Figure 2 and Figure 3 As shown, one first stress weakening portion 32 may correspond to two or three adjacent first transmission circuits 12 .

[0066] Figure 5A for Figure 2 The cross-sectional view of the thin film circuit board shown at line BB is shown in FIG. Figure 5B For hot pressing head Figure 5A For the schematic diagram of the film circuit board lamination shown in Figure 2 , Figure 3 , Figure 5A and Figure 5B When the thin film circuit board 1 is manufactured, the hot pressing head 8 is used to correspond to the position of the conductive adhesive 40 (also the position of the docking opening 31), so that the conductive adhesive 40 is heated and adheres the first substrate 10 and the second substrate 20, and the first docking circuit 11 and the second docking circuit 21 are electrically connected. For clear explanation, a virtual pressing reference area R is defined on the thin film circuit board 1, as shown in FIG. Figure 2 As shown. That is, the lamination reference area R is an area located on the first substrate 10 or the second substrate 20 for lamination by the hot pressing head 8. The lamination reference area R is distributed in the docking opening 31, and the area of ​​the lamination reference area R is larger than the area of ​​a surface of the conductive adhesive 40. Specifically, the area of ​​the lamination reference area R is smaller than the area of ​​the docking opening 31, so that the lamination reference area R can be distributed in the docking opening 31. Moreover, the area of ​​the lamination reference area R is larger than the area of ​​the surface of the conductive adhesive 40 facing the first substrate 10 or the second substrate 20, so that the lamination reference area R can completely cover the range of the conductive adhesive 40.

[0067] When the first substrate 10 and the second substrate 20 are pressed together, the thermal pressing head 8 is aligned with the pressing reference area R, and the thermal pressing head 8 is pressed downward from the upper surface of the first substrate 10. Figure 5B shown. Figure 6 for Figure 5B For an enlarged schematic diagram of area C shown, please refer to Figure 2 and Figure 6 Compared with the prior art, the first stress weakening portion 32 can increase the space between the second docking circuit 21, the inner wall of the spacer layer 30 and the first transmission circuit 12. Therefore, when the hot pressing head 8 presses down the first substrate 10, the first transmission circuit 12 can be deformed downward, so that the pressure on the first transmission circuit 12 is more uniform, so as to improve the problem of the first transmission circuit 12 being broken during the pressing process.

[0068] by Figure 1A and Figure 1B For example, the distance from one end of the conductive adhesive 94 of the conventional thin film circuit board 9 to the inner wall of the docking hole 921 is the length L1. In other words, the length L1 is the sum of the distance from the conductive adhesive 94 to the thermal press head 8 and the distance from the thermal press head 8 to the inner wall of the docking hole 921. Corresponding to the thin film circuit board 1 of this embodiment, the distance from one end of the edge of the conductive adhesive 40 facing the first stress weakening portion 32 to the inner wall of the docking opening 31 is also approximately the length L1, as shown in FIG. Figure 2 and Figure 5A As shown. That is, the length L1 is the sum of the distance from the conductive adhesive 40 to the hot pressing head 8 and the distance from the hot pressing head 8 to the inner wall of the docking opening 31. The spacer layer 30 of this embodiment also has a first stress weakening portion 32 connected to the docking opening 31, which can increase the distance from the docking opening 31 to a bottom inner wall 321 of the first stress weakening portion 32, which is referred to as the length L2. It should be noted that the bottom inner wall 321 refers to the inner wall of the first stress weakening portion 32 on the side opposite to the docking opening 31.

[0069] In other words, the distance from the end of the conductive adhesive 40 facing the first stress weakening portion 32 to the bottom inner wall 321 of the first stress weakening portion 32 is the sum of the lengths L1 and L2. Since the first stress weakening portion 32 corresponds to the first transmission circuit 12, when the first substrate 10 is pressed together, the slope of the first transmission circuit 12 from the press-fitting position with the second docking circuit 21 to the spacer layer 30 is relatively gentle (e.g. Figure 6 On the contrary, the slope of the conventional upper circuit 911 from the crimping point with the lower circuit 931 to the middle spacer 92 is steeper (as shown in FIG. Figure 1C The first transmission circuit 12 with a smaller slope can reduce the probability of wire breakage due to the shear force generated by the interaction between the hot pressing head 8 and the spacer layer 30 during pressing.

[0070] like Figure 6As shown, in this embodiment, the position where one edge of the thermal pressing head 8 is projected to the bottom surface of the first transmission circuit 12 is defined as a first projection point 121. It should be noted that, since the pressing reference area R is the area for the thermal pressing head 8 to press, the edge of the thermal pressing head 8 projected to the first transmission circuit 12 is substantially equivalent to one end of the pressing reference area R facing the first stress weakening portion 32. In addition, the position where the bottom inner wall 321 of the first stress weakening portion 32 is projected to the top surface of the first transmission circuit 12 is defined as a second projection point 122. In this embodiment, the slope m of the line between the first projection point 121 and the second projection point 122 is less than or equal to 0.0245.

[0071] Specifically, in this embodiment, the distance from the edge of the thermal pressing head 8 (i.e., the end of the pressing reference area R facing the first stress weakening portion 32) to the bottom inner wall 321 of the first stress weakening portion 32 is defined as the length L3. The length L3 may be greater than or equal to 1.25 millimeters (mm). Through the above-mentioned restriction, the slope m of the line between the first projection point 121 and the second projection point 122 may be less than or equal to 0.0245, thereby preventing the first transmission circuit 12 from being broken due to the shear force generated by the interaction between the thermal pressing head 8 and the spacer layer 30.

[0072] In addition, the conductive adhesive 40 of this embodiment is an anisotropic conductive film (ACF) having a certain thickness. When the conductive adhesive 40 is pressed by the hot pressing head 8, it will overflow to the surroundings. However, if the conductive adhesive 40 overflows to the range outside the docking opening 31, it may cause the film circuit board 1 to be abnormal and need to be discarded. In this embodiment, the first stress weakening portion 32 is connected to the docking opening 31, so that the first stress weakening portion 32 can also be used to accommodate a portion of the pressed conductive adhesive 40. That is, the first stress weakening portion 32 can also accommodate the overflow of the conductive adhesive 40.

[0073] Figure 7 FIG. 1 is a partial top view of a thin film circuit board according to a second embodiment of the present invention. Figure 7 As shown. The difference between the thin film circuit board 1a of this embodiment and the previous embodiment lies in the spacer layer 30a. Therefore, the structure and connection relationship of other components such as the first substrate 10, the second substrate 20 and the conductive adhesive 40 can refer to the previous embodiment, and the component symbols are used. Similarly, since the first substrate 10, the second substrate 20 and the spacer layer 30a are a stacked three-layer structure, they are marked at the same place. In addition, since the first docking circuit 11 and the second docking circuit 21 overlap each other, they are also marked at the same place.

[0074] The spacer layer 30a of this embodiment also includes a docking opening 31a and a plurality of first stress weakening portions 32a, and one end of the first stress weakening portion 32a is connected to the docking opening 31a. The difference from the previous embodiment is that each first stress weakening portion 32a of this embodiment corresponds to each first transmission circuit 12. In other words, one first stress weakening portion 32a of this embodiment can correspond to one first transmission circuit 12, so that the distribution area of ​​the first stress weakening portion 32a can be further reduced compared to the first embodiment, which is beneficial for application in a thin film circuit board 1a with densely distributed circuits.

[0075] Figure 8 FIG. 1 is a partial top view of a thin film circuit board according to a third embodiment of the present invention. Figure 8 As shown. The difference between the thin film circuit board 1b of this embodiment and the previous embodiment is also the spacer layer 30b. Therefore, the structure and connection relationship of other components such as the first substrate 10, the second substrate 20 and the conductive adhesive 40 can refer to the previous embodiment, and the component symbols are used. Similarly, the first substrate 10, the second substrate 20 and the spacer layer 30b are marked at the same place, and the first docking circuit 11 and the second docking circuit 21 are also marked at the same place.

[0076] The spacer layer 30b of this embodiment also includes a docking opening 31b and a plurality of first stress weakening portions 32b, and one end of the first stress weakening portion 32b is connected to the docking opening 31b. The difference from the previous embodiment is that the number of the first stress weakening portions 32b is two, and they are located on two opposite sides of the docking opening 31b, so as to correspond to the plurality of first transmission circuits 12 located on the two opposite sides. The distribution area of ​​the first stress weakening portions 32b of this embodiment is larger than that of the thin film circuit boards 1 and 1a of the first and second embodiments, and has a better effect of accommodating overflowing conductive adhesive 40.

[0077] Fig. 9A is a cross-sectional schematic diagram of a thin film circuit board according to a fourth embodiment of the present invention, Fig. 9B For hot pressing head Fig. 9A For the schematic diagram of the film circuit board lamination shown in Fig. 9A and Fig. 9BAs shown. The difference between the thin film circuit board 1c of this embodiment and the first embodiment lies in the first substrate 10c. Therefore, the structures and connection relationships of other components such as the second substrate 20, the spacer layer 30 and the conductive adhesive 40 can refer to the first embodiment, and the component symbols are used. In this embodiment, the first substrate 10c includes a first docking circuit 11c, a first transmission circuit 12c and at least one second stress weakening portion 13c. Among them, the structures of the first docking circuit 11c and the first transmission circuit 12c can refer to the first docking circuit 11 and the first transmission circuit 12 of the first embodiment, and no further description is given here. The second stress weakening portion 13c is close to the end of the first docking circuit 11c opposite to the first transmission circuit 12c. In other words, one end of the first docking circuit 11c is connected to the first transmission circuit 12c, and the other end is close to the second stress weakening portion 13c. The second stress weakening portion 13c of this embodiment is also a hollowed-out opening structure, so that the end of the first docking circuit 11c opposite to the first transmission circuit 12c forms a swingable free end structure. In other words, an end of the first connecting circuit 11 c adjacent to the second stress weakening portion 13 c forms a free end structure.

[0078] When the hot pressing head 8 presses down the first substrate 10c, in addition to the first stress weakening portion 32, the structure of the free end formed by the second stress weakening portion 13c can also provide the first substrate 10c with a larger deformation amount. Therefore, the second stress weakening portion 13c can also reduce the probability of the first transmission circuit 12c being broken due to the shear force generated by the interaction between the hot pressing head 8 and the spacer layer 30 during the pressing. In short, the structure of the second stress weakening portion 13c can prevent the first transmission circuit 12c from being broken due to the shear force. In other embodiments, the second stress weakening portion 13c can also be a thinned groove, which can also provide the first substrate 10c with a larger deformation amount to prevent the first transmission circuit 12c from being broken.

[0079] Fig.10 FIG. 5 is a cross-sectional view of a thin film circuit board according to a fifth embodiment of the present invention. Fig.10As shown. The difference between the thin film circuit board 1d of this embodiment and the first embodiment lies in the second substrate 20d. Therefore, the structure and connection relationship of other components such as the first substrate 10, the spacer layer 30 and the conductive adhesive 40 can refer to the first embodiment, and the component symbols are used. In this embodiment, the second substrate 20d also includes at least one third stress weakening portion 23d, corresponding to part of the first transmission circuit 12. Specifically, the third stress weakening portion 23d is adjacent to one end of the second docking circuit 21d, and the upper side of the third stress weakening portion 23d corresponds to part of the first transmission circuit 12 and part of the spacer layer 30. The third stress weakening portion 23d of this embodiment can also be a hollowed opening or a thinned groove to reduce the thickness here, thereby providing a larger deformation amount. When the hot pressing head 8 presses down the first substrate 10, the portion of the bottom inner wall 321 of the spacer layer 30 close to the first stress weakening portion 32 can move in the direction of the third stress weakening portion 23d, that is, move downward again, so as to avoid the first transmission circuit 12 above from breaking. Therefore, the structure of the third stress weakening portion 23 d can also prevent the first transmission circuit 12 from being broken due to the shear force.

[0080] In summary, the thin film circuit board according to the present invention includes a first substrate, a second substrate, a spacer layer and a conductive adhesive. The spacer layer is arranged between the first substrate and the second substrate. The conductive adhesive is arranged in the docking opening of the spacer layer and contacts the first docking circuit of the first substrate and the second docking circuit of the second substrate respectively. The spacer layer has a first stress weakening portion to increase the deformation of the first substrate and its first transmission circuit. Therefore, when the hot pressing head presses down the first substrate, the structure of the aforementioned (first, second or third) stress weakening portion is used to increase the deformation of the first transmission circuit, thereby making the pressure on the first transmission circuit more uniform, so as to achieve the effect of preventing the first transmission circuit from breaking during the pressing process.

[0081] It should be noted that the above embodiments are provided for the purpose of illustration, and the scope of rights claimed by the present invention should be based on the claims, rather than being limited to the above embodiments.

Claims

1. A thin film circuit board, characterized in that: include: A first substrate, comprising a plurality of first connecting circuits and at least one first transmission circuit, wherein the first transmission circuit is connected to one of the plurality of first connecting circuits; a second substrate, comprising a plurality of second docking circuits, respectively corresponding to the plurality of first docking circuits; a spacer layer disposed between the first substrate and the second substrate, the spacer layer comprising a butt joint opening and at least one first stress weakening portion, one end of the first stress weakening portion being connected to the butt joint opening, and the first stress weakening portion corresponding to the first transmission circuit; as well as A conductive adhesive is disposed in the butt joint opening and is in contact with the first butt joint circuit and the second butt joint circuit respectively.

2. The thin film circuit board according to claim 1, wherein: Also includes: A pressing reference area is distributed in the butting opening, and the area of ​​the pressing reference area is larger than the area of ​​a surface of the conductive adhesive.

3. The thin film circuit board according to claim 2, characterized in that: One end of the pressing reference area is projected onto a bottom surface of the first transmission circuit as a first projection point, and a bottom inner wall of the first stress weakening portion is projected onto a top surface of the first transmission circuit as a second projection point. The slope of the line between the first projection point and the second projection point is less than or equal to 0.0245.

4. The thin film circuit board according to claim 2, wherein: A distance from an end of the pressing reference area facing the first stress weakening portion to an inner wall of a bottom side of the first stress weakening portion is greater than or equal to 1.25 mm.

5. The thin film circuit board according to claim 1, wherein: The first stress weakening portion is an opening extending outward from one end of the butt opening.

6. The thin film circuit board according to claim 1, wherein: The first stress weakening portion accommodates a portion of the pressed conductive adhesive.

7. The thin film circuit board according to claim 1, wherein: The first substrate includes a plurality of the first transmission circuits, the spacing layer includes a plurality of the first stress weakening portions, and each of the first stress weakening portions corresponds to each of the first transmission circuits.

8. The thin film circuit board according to claim 1, wherein: The first substrate includes a plurality of the first transmission circuits, and the first stress weakening portion corresponds to the first transmission circuits.

9. The thin film circuit board according to claim 1, wherein: The first substrate further includes at least one second stress weakening portion, which is close to an end of the plurality of first connecting circuits opposite to the first transmission circuit.

10. The thin film circuit board according to claim 9, wherein: The second stress weakening portion is an open structure, so that one end of the plurality of first connecting circuits adjacent to the second stress weakening portion forms a free end structure.

11. The thin film circuit board according to claim 1, wherein: The second substrate further includes at least one third stress weakening portion, which is adjacent to one end of the second docking circuit and corresponds to a portion of the first transmission circuit.

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