阅读说明：本技术 电子装置 (Electronic device ) 是由 朱伟正 刘佳秤 姜明甫 于 2020-03-17 设计创作，主要内容包括：本发明公开了一种电子装置,其包括一挠性电路结构,该挠性电路结构包括：一挠性基材,具有一表面,且该表面上设置有多个接垫；以及一绝缘体,设置于该挠性基材上,且设置于该多个接垫中的两个相邻接垫之间。(The invention discloses an electronic device, which comprises a flexible circuit structure, wherein the flexible circuit structure comprises: a flexible substrate having a surface, and a plurality of pads disposed on the surface; and an insulator disposed on the flexible substrate and between two adjacent pads of the plurality of pads.)

1. An electronic device, comprising:

a flexible circuit structure comprising:

a flexible substrate having a surface, and a plurality of pads disposed on the surface; and

an insulator disposed on the flexible substrate and between two adjacent pads of the plurality of pads.

2. The electronic device of claim 1, wherein the insulator comprises an insulating layer disposed between the two adjacent pads.

3. The electronic device of claim 2, wherein the pads each include a contact surface and two side surfaces, the contact surface is disposed between the two side surfaces and connected to the two side surfaces, and the insulating layer is disposed on at least one of the two side surfaces of the pads.

4. The electronic device of claim 2, wherein the insulating layer further comprises an insulating post.

5. The electronic device of claim 4, wherein the insulating pillar has a fourth maximum height along a normal direction of the flexible substrate, one of the pads has a second maximum height along the normal direction of the flexible substrate, and the fourth maximum height is less than or equal to the second maximum height.

6. The electronic device of claim 4, wherein the insulating pillar has a fourth maximum height along a normal direction of the flexible substrate, one of the pads has a second maximum height along the normal direction of the flexible substrate, and the fourth maximum height is greater than the second maximum height.

7. The electronic device of claim 1, wherein the insulator has a maximum height in a normal direction of the flexible substrate, one of the pads has a maximum height in the normal direction of the flexible substrate, and the maximum height of the insulator is less than or equal to the maximum height of the one of the pads.

8. The electronic device of claim 1, wherein the insulator has a maximum height in a normal direction of the flexible substrate, one of the pads has a maximum height in the normal direction of the flexible substrate, and the maximum height of the insulator is greater than the maximum height of the one of the pads.

9. The electronic device of claim 8, further comprising a conductive paste disposed between the flexible circuit structure and a substrate, the conductive paste including a plurality of conductive particles having an average particle size, wherein the maximum height of the insulator is less than a sum of the maximum height and the average particle size of one of the pads.

10. The electronic device of claim 9, wherein the maximum height of the insulator is less than or equal to the sum of the maximum height of one of the pads and 30% -70% of the average grain size.

Technical Field

The present invention relates to an electronic device, and more particularly, to an electronic device having a flexible circuit structure.

Background

With the trend of electronic products continuously moving toward narrow frames, it is beneficial to use a Flexible Printed Circuit (FPC) to connect electronic components. For example, the ability to provide a larger display area is one of the key factors influencing the purchase desire of consumers, and the new generation of display devices can successfully realize the borderless design, i.e., the FPC is used to electrically connect the peripheral driver chips, so that the driver chips originally disposed on the periphery of the display panel can be disposed on the back side of the display panel, thereby maximizing the display area of the display panel.

However, the adhesion between the polyimide film and the metal pad (pad) of the FPC and the adhesive material is not good, and thus the peeling problem often occurs. Therefore, it is desirable to provide an electronic device to improve or eliminate the above problems.

Disclosure of Invention

The invention provides an electronic device which is characterized by comprising a flexible circuit structure, wherein the flexible circuit structure comprises a flexible substrate and an insulator, the flexible substrate is provided with a surface, a plurality of connecting pads are arranged on the surface, and the insulator is arranged on the flexible substrate and is arranged between two adjacent connecting pads in the connecting pads.

Other novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.

Drawings

FIG. 1 is a top view of an electronic device according to an embodiment of the invention;

FIG. 2 is a partial cross-sectional view of an electronic device according to an embodiment of the invention;

FIG. 3 is a partial cross-sectional view of an electronic device according to an embodiment of the invention;

FIG. 4 is a partial cross-sectional view of an electronic device according to an embodiment of the invention;

FIG. 5 is a partial cross-sectional view of an electronic device according to an embodiment of the invention;

FIG. 6 is a partial cross-sectional view of an electronic device according to an embodiment of the invention;

fig. 7 is a partial cross-sectional view of an electronic device according to an embodiment of the invention.

Description of the symbols:

10 flexible circuit structure

11 Flexible base Material

110 surface

111 first pad

1111 contact surface

1112 side face

1113 side surface

121 insulating layer

122 insulating layer

123 insulating column

124 insulating column

125 insulating layer

126 insulating column

127 insulating layer

128 insulating column

20 base plate

21 display area

22 non-display area

221 second pad

30 circuit board

40 conductive adhesive

41 colloid

42 conductive particles

H1 first maximum height

H2 second maximum height

H3 third maximum height

H4 fourth maximum height

N normal direction

Average particle diameter of Ro

Rd pressing particle size

Detailed Description

The following embodiments are provided to clearly demonstrate the above and other technical matters, features and/or effects of the present invention when read in conjunction with the accompanying drawings. Through the description of the specific embodiments, people will further understand the technical means and effects adopted by the invention to achieve the above-mentioned purposes. Further, since the present disclosure should be readily understood and implemented by those skilled in the art, all equivalent substitutions or modifications which do not depart from the concept of the present invention are intended to be included in the claims.

It should be noted that, unless otherwise specified herein, the use of the singular reference of "a" or "an" element is not intended to refer to only a single such element, but rather to one or more such elements.

Moreover, ordinal numbers such as "first" or "second" in the specification and claims are used merely to describe a claimed element, and do not represent or imply any order of ordinal numbers for the claimed element, and not between a claimed element and another claimed element or step of a manufacturing method. The use of ordinals is merely to distinguish one request element having a particular name from another request element having the same name.

In addition, in the specification and claims, for example, a component may be disposed on another component, or the like, may mean not only that the component directly contacts the other component, but also that the component indirectly contacts the other component.

Furthermore, the terms such as "adjacent" in the description and in the claims are used for describing mutual proximity and do not necessarily indicate mutual contact.

In addition, the term "connected" in the specification and claims may mean not only directly connected to another element but also indirectly connected to another element or electrically connected to another element.

Furthermore, the technical features of different embodiments disclosed in the invention can be combined to form another embodiment.

In addition, the electronic device disclosed in the present invention may include a display device, an antenna device, a sensing device, a touch electronic device (touch display), a curved electronic device (curved display), or a non-rectangular electronic device (free shape display), but is not limited thereto. The electronic device can be a bendable or flexible electronic device. The electronic device may include, for example, a liquid crystal (liquid crystal), a light emitting diode (led), a fluorescent light (fluorescence), a phosphorescent light (phor), other suitable display media, or a combination thereof, but is not limited thereto. The light emitting diode may include, for example, an Organic Light Emitting Diode (OLED), a submillimeter light emitting diode (mini LED), a micro LED, a quantum dot light emitting diode (QD, which may be, for example, a QLED, a QDLED), other suitable materials, or any combination thereof, but is not limited thereto. The display device may include, for example, a tiled display device, but is not so limited. The antenna device may be, for example, a liquid crystal antenna, but is not limited thereto. The antenna device may, for example, include a tiled antenna device, but is not so limited. It should be noted that the electronic device can be any permutation and combination of the foregoing, but not limited thereto. In addition, the exterior of the electronic device may be rectangular, circular, polygonal, a shape with curved edges, or other suitable shapes. The electronic device may have a driving system, a control system, a light source system, a shelf system, and other peripheral systems to support the display device, the antenna device, or the splicing device. The present invention will be described below with reference to the display device as an electronic device, but the present invention is not limited thereto.

Fig. 1 is a top view of an electronic device according to an embodiment of the invention. As shown in fig. 1, the electronic device of the present embodiment includes: the flexible circuit structure 10 has a signal transmission function, and is connected to the substrate 20 and the circuit board 30 respectively, and transmits signals (such as gate signals or source signals) between the substrate 20 and the circuit board 30. However, the present invention is not limited thereto. The following description will be made in detail by taking the connection structure of the flexible circuit structure 10 and the substrate 20 as an example.

The substrate 20 may be used for a display device, an antenna device, a sensing device or a splicing device, and an active device, which may include a transistor, may be disposed on the substrate 20. The substrate 20 includes a flexible substrate or a non-flexible substrate, and the material thereof may include, for example, glass, quartz, a wafer, a sapphire substrate, Polycarbonate (PC), Polyimide (PI), polypropylene (PP), polyethylene terephthalate (PET), other suitable materials, or a combination thereof. However, the present invention is not limited thereto.

In the present embodiment, the substrate 20 includes a display region 21 and a non-display region 22, the non-display region 22 is disposed beside the display region 21, and the non-display region 22 is electrically connected to the flexible circuit structure 10. Fig. 2 is a partial cross-sectional view taken along line a-a' in fig. 1, and as shown in fig. 2, the flexible circuit structure 10 includes a flexible substrate 11 and an insulator (an insulating layer 121 in fig. 2), wherein the flexible substrate 11 has a surface 110, and a plurality of first pads 111 are disposed on the surface 110; the insulator is disposed on the flexible substrate 11 and between two adjacent first pads 111 of the plurality of first pads 111.

The material of the flexible substrate 11 may include, for example, Polyimide (PI), Polycarbonate (PC), polypropylene (PP), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), acryl, other suitable materials, or a combination thereof. However, the present invention is not limited thereto.

The flexible circuit structure 10 can be formed on a flexible substrate 11 by a process including, for example, a printing process or a Chemical Vapor Deposition (CVD), lithography, etching, etc. However, the present invention is not limited thereto. In addition, the first pad 111 is a conductive material, and may include a metal material (e.g., Au, Cu, Ni, Ag, Ti, Cr, Mo, or a1), an alloy material, a conductive metal oxide, other suitable materials, or a combination thereof. However, the present invention is not limited thereto.

The flexible substrate 11 of the flexible circuit structure 10 may have active devices (e.g., driver chips) or passive devices (e.g., resistors, capacitors, or inductors) disposed thereon. In some embodiments, a driving chip may be disposed on the flexible substrate 11 of the flexible circuit structure 10, the driving chip electrically connects the circuit board 30 and the first pads 111, and the first pads 111 are electrically connected to the conductive traces of the substrate 20, so that the driving chip can receive signals from the circuit board 30 and then transmit the signals to the substrate 20 through the first pads 111. However, the present invention is not limited thereto.

The insulator material may comprise non-conductive material, for example, the insulator may comprise a polymer material, a silicon oxynitride, other suitable materials, or combinations thereof. For example, the polymer material may include Polyimide (PI), Polyethylene (PE), polyethylene terephthalate (pet)_te_rPET), Polyamide (Polyamide), other suitable materials, or combinations of the above; the silicon oxide compound may comprise silicon dioxide; the silicon nitrogen compound may comprise Si₃N₄(ii) a The silicon oxynitride may contain Si₂N₂And O. In this embodiment, the material of the insulator is Si₃N₄. However, the present invention is not limited thereto.

The insulator may be in the shape of a layer, a column, a cone, or other suitable shape or combination of shapes. In some embodiments, the insulator may be disposed on the surface 110 between any two adjacent first pads 111 or between any two adjacent first pads 111. In some embodiments, the insulator may be disposed on the surface 110 between two adjacent first pads 111 or between two adjacent first pads 111 at intervals. In the present embodiment, the insulator includes an insulating layer 121, and the insulating layer 121 is disposed on the surface 110 between two adjacent first pads 111. However, the present invention is not limited thereto.

When the flexible substrate 11 is laid flat, the flexible substrate 11 extends substantially along a first direction, a normal direction N of the flexible substrate 11 is substantially perpendicular to the first direction, and an included angle between the first direction and the normal direction N is between 80 ° and 100 °. The insulating layer 121 has a first maximum height H1 in the normal direction N of the flexible substrate 11, and the first pads 111 have a second maximum height H2 in the normal direction N of the flexible substrate 11, wherein the first maximum height H1 may be less than or equal to the second maximum height H2. In the present embodiment, the first maximum height H1 is less than the second maximum height H2, but the present invention is not limited thereto. The first maximum height H1 may be, for example, between 0.1 μm and 10 μm, between 0.1 μm and 6 μm, between 0.1 μm and 3 μm, or between 0.1 μm and 2 μm. The smaller the first maximum height H1, the better the flexibility of the flex circuit structure is maintained. The second maximum height H2 may be, for example, between 0.6 μm and 12 μm, between 0.6 μm and 10 μm, between 0.6 μm and 8 μm, between 0.6 μm and 5 μm, between 0.6 μm and 3 μm, or between 0.6 μm and 2 μm. However, the present invention is not limited thereto.

In some embodiments, the electronic device includes a conductive adhesive 40 between the flexible circuit structure 10 and the substrate 20, the flexible circuit structure 10 is electrically connected to the substrate 20 through the conductive adhesive 40, and the insulating layer 121 is located between the flexible substrate 11 and the conductive adhesive 40. The conductive paste 40 may include a colloid 41 and a plurality of conductive particles 42 dispersed in the colloid 41, wherein the colloid 41 may include a resin adhesive, such as epoxy resin or polyimide, which is moisture-proof, heat-resistant, and has a function of adhesion and insulation; the conductive particles 42 may include gold spherical particles, such as gold spherical particles having a plastic sphere at the center and sequentially coated with a nickel layer and a gold layer on the surface of the plastic sphere. The Conductive paste 40 may include an Anisotropic Conductive paste (ACF) or an Anisotropic Conductive Film (ACF). However, the present invention is not limited thereto.

In some embodiments, the flexible circuit structure 10 has no pixel unit, and thus has no display function, and the display area 21 of the substrate 20 may include a plurality of thin film transistors and a plurality of pixel units for displaying images. In some embodiments, the non-display region 22 of the substrate 20 may have a plurality of second pads 221, and the second pads 221 may be electrically connected to the thin film transistors or the pixel units, respectively. In addition, the second pad 221 may be a conductive material, for example, including a metal material (e.g., Au, Cu, Ni, Ag, Ti, Cr, Mo, or Al), an alloy material, a conductive metal oxide (e.g., ITO, IZO, ITZO, IGZO, or AZO), other suitable materials, or a combination thereof. In addition, the thickness of the second pad 221 may be between 0.2 μm and 1.4 μm, between 0.2 μm and 1.2 μm, between 0.2 μm and 1 μm, between 0.2 μm and 0.8 μm, between 0.2 μm and 0.4 μm, but the invention is not limited thereto.

In some embodiments, the conductive adhesive 40 may be disposed on the flexible substrate 11 of the flexible circuit structure 10, for example, the conductive adhesive 40 is disposed on the first pads 111 and the insulating layer 121, the substrate 20 is aligned and disposed on the conductive adhesive 40, and then the flexible circuit structure 10 and the substrate 20 are pressed together, so that the flexible circuit structure 10 and the substrate 20 are fixed to each other, the conductive particles 42 in the conductive adhesive 40 can electrically connect the first pads 111 and the second pads 221, so that signals can be transmitted to the substrate 20 and input to the plurality of pixel units. However, the present invention is not limited thereto.

In the embodiment, the adhesion strength of the conductive adhesive 40 to the insulating layer 121 is better than the adhesion strength of the conductive adhesive 40 to the flexible substrate 11, so that the adhesion force between the flexible circuit structure 10 and the conductive adhesive 40 is improved, and the flexible circuit structure 10 and the substrate 20 can be connected through the conductive adhesive 40, thereby enhancing the adhesion strength between the flexible circuit structure 10 and the substrate 20, and improving the product reliability of the electronic device.

Fig. 3 is a partial cross-sectional view of an electronic device according to another embodiment of the invention. The electronic device of the present embodiment is similar to that disclosed in fig. 2, except for the following differences.

In this embodiment, the first pads 111 respectively have a contact surface 1111 and two side surfaces 1112 and 1113, the contact surface 1111 is opposite to the surface 110, and the contact surface 1111 is disposed between the two side surfaces 1112 and 1113 and connected to the two side surfaces 1112 and 1113. In the embodiment, the insulator includes an insulating layer 122, and the insulating layer 122 is disposed on the surface 110 between two adjacent first pads 111 and on the two side surfaces 1112 and 1113 of the first pads 111. In some embodiments, the insulating layer 122 may be disposed on a portion of the surface 110 between two adjacent first pads 111 and extend onto a portion of one or both of the two side surfaces 1112 and 1113 of the first pads 111. In some embodiments, the insulating layer 122 may be disposed on a portion of the surface of one or both of the two side surfaces 1112 and 1113 of the first pad 111.

The insulating layer 122 has a first maximum height H1 in the normal direction N of the flexible substrate 11, and the first pads 111 have a second maximum height H2 in the normal direction N of the flexible substrate 11, wherein the first maximum height H1 may be less than or equal to the second maximum height H2. The same or similar elements in fig. 3 and fig. 2 will be assigned the same or similar reference numerals and their detailed descriptions will be omitted. In the present embodiment, the conductive paste 40 may be disposed on the first pads 111 and the insulating layer 122 of the flexible circuit structure 10, and the conductive paste 40 is disposed between the flexible circuit structure 10 and the substrate 20, wherein the colloid 41 in the conductive paste 40 may respectively adhere to the insulating layer 122 on the surface 110 and the substrate 20, and the conductive particles 42 in the conductive paste 40 may electrically connect the first pads 111 and the second pads 221.

In the embodiment, since the adhesion strength of the conductive adhesive 40 to the insulating layer 122 is better than the adhesion strength of the conductive adhesive 40 to the flexible substrate 11, the flexible circuit structure 10 and the substrate 20 can be connected by the conductive adhesive 40, so as to improve the adhesion force between the flexible circuit structure 10 and the conductive adhesive 40, and further enhance the adhesion strength between the flexible circuit structure 10 and the substrate 20, in addition, the distance between the pads is smaller and smaller due to the density of the high-resolution pads being denser, in this design, the insulating layer 122 extends from the surface of the flexible substrate 11 to the side surfaces 1112 and 1113 of the first pads, so as to avoid the problem of short circuit caused by too small distance between two adjacent first pads 111 or too high density of the conductive particles 42, thereby improving the product reliability of the electronic device.

Fig. 4 is a partial cross-sectional view of an electronic device according to another embodiment of the invention. The electronic device of the present embodiment is similar to that disclosed in fig. 2, except for the following differences.

In the present embodiment, the insulator includes an insulating pillar 123, the insulating pillar 123 is disposed on the surface 110 of the flexible substrate 11 and disposed between two adjacent first pads 111, and the conductive paste 40 is disposed on the surface 110, the insulating pillar 123 and the first pads 111, and the conductive paste 40 is disposed between the flexible circuit structure 10 and the substrate 20, wherein the colloid 41 in the conductive paste 40 can respectively adhere to the surface 110, the insulating pillar 123 and the substrate 20, and the conductive particles 42 in the conductive paste 40 can electrically connect the first pads 111 and the second pads 221. In the embodiment, the insulating pillar 123 may further separate the conductive particles 42 between the first pads 111 to prevent a short circuit between the first pads 111. In the normal direction N of the flexible substrate 11, the insulating pillar 123 has a third maximum height H3, and the third maximum height H3 may be less than or equal to the second maximum height H2 of the first pad 111. However, the present invention is not limited thereto.

In the embodiment, the insulating pillar 123 can increase the contact area between the conductive paste 40 and the flexible circuit structure 10, and the adhesion strength of the conductive paste 40 to the insulating pillar 123 is better than the adhesion strength of the conductive paste 40 to the flexible substrate 11, so as to improve the adhesion of the conductive paste 40 to the flexible circuit structure 10, thereby improving the product reliability of the electronic device.

Fig. 5 is a partial cross-sectional view of an electronic device according to another embodiment of the invention. The electronic device of the present embodiment is similar to that disclosed in fig. 4, except for the following differences.

In the embodiment, the insulator includes an insulating pillar 124, the insulating pillar 124 is disposed on the surface 110 of the flexible substrate 11 and between two adjacent first pads 111, in the normal direction N of the flexible substrate 11, the insulating pillar 124 has a third maximum height H3, the third maximum height H3 is greater than the second maximum height H2 of the first pads 111, the flexible substrate 11 and the conductive paste 40 are peeled off due to a rebound force generated when the flexible substrate 11 is seriously depressed and deformed, and the insulating pillar 124 can provide a supporting force in the process of laminating the flexible substrate 11 and the substrate 20, so as to prevent the flexible substrate 11 from being depressed and deformed or the conductive particles 42 from being excessively deformed.

In addition, in the embodiment, the conductive particles 42 in the conductive paste 40 have an average particle size Ro before being bonded, and the third maximum height H3 is smaller than the sum of the second maximum height H2 and the average particle size Ro, so as to prevent the insulating pillars 124 from interfering with the bonding of the flexible substrate 11 and the substrate 20. In the process of laminating the flexible substrate 11 and the substrate 20, the deformation amount of the conductive particles 42 between the first pad 111 and the second pad 221 is 30% to 70%, that is, the lamination particle diameter Rd of the conductive particles 42 after being laminated is 30% to 70% of the average particle diameter Ro, in some embodiments, the deformation amount of the conductive particles 42 between the first pad 111 and the second pad 221 may be 30% to 70%, 30% to 60%, or 30% to 50%, and if the conductive particles 42 are excessively laminated, the conductive particles 42 may be damaged, so the deformation amount of the conductive particles 42 is not preferably too large. Thus, third maximum height H3 may be between the sum of second maximum height H2 and second maximum height H2 and 30% -70% of average particle size Ro. In this embodiment, the average particle size Ro may be between 0.3 μm and 7 μm, between 0.3 μm and 5 μm, between 0.3 μm and 4 μm, between 0.3 μm and 3 μm, or between 0.3 μm and 2 μm. However, the present invention is not limited thereto.

In the embodiment, the insulating pillar 124 not only provides a supporting force during the pressing process to prevent the flexible substrate 11 from being deformed due to sinking or the conductive particles 42 from being excessively deformed, but also increases the contact area between the conductive adhesive 40 and the flexible circuit structure 10, and the adhesion strength of the conductive adhesive 40 to the insulating pillar 124 is better than the adhesion strength of the conductive adhesive 40 to the flexible substrate 11, so that the adhesion of the conductive adhesive 40 to the flexible circuit structure 10 can be improved, thereby improving the product reliability of the electronic device.

Fig. 6 is a partial cross-sectional view of an electronic device according to another embodiment of the invention. The electronic device of the present embodiment is similar to that disclosed in fig. 2 or fig. 5, except for the following differences.

In the present embodiment, the insulator includes an insulating layer 125 similar to that shown in fig. 2 and an insulating pillar 126 similar to that shown in fig. 5, wherein the insulating layer 125 is disposed on all surfaces of the surface 110 between two adjacent first pads 111, the insulating pillar 126 is disposed on the insulating layer 125 and between two adjacent first pads 111, the conductive paste 40 is disposed on the insulating layer 125, the insulating pillar 126, and the first pads 111, and the conductive paste 40 is disposed between the flexible circuit structure 10 and the substrate 20, wherein the glue 41 in the conductive paste 40 can respectively connect the insulating layer 125, the insulating pillar 126, and the substrate 20, and the conductive particles 42 in the conductive paste 40 can electrically connect the first pads 111 and the second pads 221. However, the present invention is not limited thereto. In some embodiments, the insulating layer 125 and the insulating pillar 126 may be fabricated in the same process, in some embodiments, the insulating layer 125 and the insulating pillar 126 may be fabricated in different processes, and the insulating layer 125 and the insulating pillar 126 may be made of the same material or different materials, for example, the insulating layer 125 may be an inorganic material, and the insulating pillar 126 may be an organic material, and are fabricated in different processes; alternatively, the insulating layer 125 and the insulating pillar 126 are made of organic materials and are fabricated by different processes or by the same process. In some embodiments, the insulating layer 125 and the insulating column 126 are the same material, and the insulating column 126 may be a protruding portion of the insulating layer 125. However, the present invention is not limited thereto. The same or similar elements in fig. 6 as those in the previous embodiment will be denoted by the same or similar reference numerals, and the detailed description thereof will be omitted. The insulating layer 125 may have a first maximum height H1, and the insulating pillar 126 may have a fourth maximum height H4, wherein the sum of the first maximum height H1 and the fourth maximum height H4 (i.e., the maximum height of the insulator in the normal direction N of the flexible substrate 11) is greater than the second maximum height H2 of the first pad 111. In addition, in the embodiment, the conductive particles 42 in the conductive paste 40 have an average particle size Ro before being pressed, and the sum of the first maximum height H1 and the fourth maximum height H4 is smaller than the sum of the second maximum height H2 and the average particle size Ro. In the process of bonding the flexible substrate 11 and the substrate 20, the deformation amount of the conductive particles 42 between the first pads 111 and the second pads 221 is 30% to 70%, that is, the bonding particle diameter Rd of the conductive particles 42 after being bonded is 30% to 70% of the average particle diameter Ro, and in some embodiments, the deformation amount of the conductive particles 42 between the first pads 111 and the second pads 221 may be 30% to 70%, 30% to 60%, or 30% to 50%. If the conductive particles 42 are pressed excessively, the conductive particles 42 are broken, and thus the deformation amount of the conductive particles 42 is not preferably too large. Thus, the sum of first maximum height H1 and fourth maximum height H4 may be between the sum of second maximum height H2 and second maximum height H2 and 30% -70% of average particle size Ro. However, the present invention is not limited thereto.

It can be understood that the present embodiment can achieve the effects of the foregoing embodiments shown in fig. 2 or fig. 5, and therefore, the repeated description is omitted.

Fig. 7 is a partial cross-sectional view of an electronic device according to another embodiment of the invention. The electronic device of the present embodiment is similar to that disclosed in fig. 3 or fig. 5, except for the following differences.

In the present embodiment, the insulator includes an insulating layer 127 similar to that shown in fig. 3 and an insulating pillar 128 similar to that shown in fig. 5, wherein the insulating layer 127 is disposed on all surfaces of the surface 110 between two adjacent first pads 111 and on the two side surfaces 1112 and 1113 of the first pads 111, the insulating pillar 128 is disposed on the insulating layer 127 and between two adjacent first pads 111, the conductive paste 40 is disposed on the insulating layer 127, the insulating pillar 128 and the first pads 111, and the conductive paste 40 is disposed between the flexible circuit structure 10 and the substrate 20, wherein the colloid 41 in the conductive paste 40 can respectively connect the insulating layer 127, the insulating pillar 128 and the substrate 20, and the conductive particles 42 in the conductive paste 40 can electrically connect the first pads 111 and the second pads 221. However, the present invention is not limited thereto. In some embodiments, the insulating layer 127 and the insulating pillar 128 may be fabricated in the same process, in some embodiments, the insulating layer 127 and the insulating pillar 128 may be fabricated in different processes, and the insulating layer 127 and the insulating pillar 128 may be made of the same material or different materials, for example, the insulating layer 127 may be an inorganic material, and the insulating pillar 128 may be an organic material, and are fabricated in different processes; alternatively, the insulating layer 127 and the insulating pillar 128 are made of organic materials, but are made by different processes or the same process. In some embodiments, the insulating layer 127 and the insulating column 128 are the same material, and the insulating column 128 can be considered a protruding portion of the insulating layer 127. However, the present invention is not limited thereto. The same or similar elements in fig. 7 as those in the previous embodiment will be denoted by the same or similar reference numerals, and the description thereof will be omitted.

It can be understood that the present embodiment can achieve the effects of the foregoing embodiments shown in fig. 3 or fig. 5, and therefore, the description of the repeated portions is omitted.

The above embodiments describe the connection manner between the flexible circuit structure 10 and the circuit board 20, but the invention is not limited thereto, and any electronic device that transmits signals through the pads can be connected to the flexible circuit structure 10 of the invention for signal transmission.

Although the present invention has been described in connection with the embodiments, it should be understood that many other possible modifications and variations may be made without departing from the spirit and scope of the invention as described in the claims.