Electronic device

An electronic device includes a flexible circuit structure. The flexible circuit structure includes a flexible substrate and an insulator. The flexible substrate has a surface on which a plurality of pads are disposed. The insulator is disposed on the flexible substrate and is disposed between two adjacent pads of the plurality of pads.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefits of the Chinese Patent Application Serial Number 202010185773.7, filed on Mar. 17, 2020, the subject matter of which is incorporated herein by reference.

BACKGROUND

1. Field of the Disclosure

The present disclosure relates to an electronic device. More specifically, the present disclosure relates to an electronic device with a flexible circuit structure.

2. Description of Related Art

With the development of electronic products toward narrow borders, it is advantageous in using flexible printed circuit (FPC) boards to connect electronic components. For example, the ability to provide a larger display area is one of the key factors that affect consumers' purchase intentions. The reason why the display devices of a new generation can successfully achieve a borderless design is to use FPC to electrically connect the peripheral driver chips, so that the driver chips that are originally arranged on the periphery of the display panel can thus be arranged on the back side of the display panel, so as to maximize the display area of the display panel.

However, due to the poor adhesion between the polyimide film of the FPC and the metal pads and the adhesive, it is likely to encounter the peeling problems. Therefore, it is desired to provide an electronic device to improve or eliminate the aforementioned problems.

SUMMARY

The present disclosure provides an electronic device characterized by including a flexible circuit structure. The flexible circuit structure includes a flexible substrate and an insulator, wherein the flexible substrate has a surface on which a plurality of pads are disposed, and the insulator is arranged on the flexible substrate and between two adjacent pads of the plurality of pads.

DETAILED DESCRIPTION OF EMBODIMENT

The implementation of the present disclosure is illustrated by specific embodiments to enable persons skilled in the art to easily understand the other advantages and effects of the present disclosure by referring to the disclosure contained therein. The present disclosure is implemented or applied by other different, specific embodiments. Various modifications and changes can be made in accordance with different viewpoints and applications to details disclosed herein without departing from the spirit of the present disclosure.

It should be noted that, in the present specification, when a component is described to comprise an element, it means that the component may comprise one or more of the elements, and it does not mean that the component has only one of the element, except otherwise specified.

Ordinal numbers, such as “first” and “second”, used herein are intended to distinguish components rather than disclose explicitly or implicitly that names of the components bear the wording of the ordinal numbers. The ordinal numbers do not imply what order a component and another component are in terms of space, time or steps of a manufacturing method. The ordinal numbers are only intended to distinguish a component with a name from another component with the same name.

In addition, the term “on” used herein may refer to two components in direct contact with each other or refer to two components not in direct contact with each other.

In addition, the term “adjacent” used herein may refer to describe mutual proximity and does not necessarily mean mutual contact.

In addition, the term “connect” is intended not only directly connect with other element, but also intended indirectly connect and electrically connect with other element.

In addition, the technical features of the different embodiments disclosed in the present disclosure can be combined to form another embodiment.

In addition, the electronic device disclosed in the present disclosure may include a display device, an antenna device, a sensing device, a touch display device, a curved display device, or a free shape display device, but is not limited thereto. The electronic device may be a bendable or flexible electronic device. The electronic device may include, for example, liquid crystal, light emitting diode, fluorescence, phosphor, 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 sub-millimeter light emitting diode (mini LED), a micro light emitting diode (micro LED) or a quantum dot (QD) light emitting diode (for example, QLED, QDLED) or other suitable materials or a combination thereof, but is not limited thereto. The display device may include, for example, a tiled display device, but is not limited thereto. The antenna device may be, for example, a liquid crystal antenna, but is not limited thereto. The antenna device may include, for example, a tiled antenna device, but is not limited thereto. It should be noted that the electronic device may be a combination of the foregoing, but is not limited thereto. In addition, the appearance of the electronic device may be rectangular, circular, polygonal, a shape with curved edges, or other suitable shapes. The electronic device may have peripheral systems such as a driving system, a control system, a light source system, a shelf system, etc., to support a display device, an antenna device, or a tiled device. Hereinafter, the display device will be used as an electronic device for illustrative purpose only, but the disclosure is not limited thereto.

FIG. 1is a schematic view of an electronic device according to an embodiment of the present disclosure. As shown inFIG. 1, the electronic device of this embodiment includes: a flexible circuit structure10, a substrate20, and a circuit board30. The flexible circuit structure10has a signal transmission function, and can be connected to the substrate20and the circuit board30, respectively, for transmitting signals between the substrate20and the circuit board30(for example, gate signals or source signals). However, the present disclosure is not limited to this. The connection structure between the flexible circuit structure10and the substrate20will be described in detail below as an example.

The substrate20can be used for a display device, an antenna device, a sensing device or a tiled device. The substrate20may be provided with an active component, and the active component may include a transistor. The substrate20may be a flexible substrate or a non-flexible substrate, and the material of the substrate20may include, for example, glass, quartz, wafer, sapphire substrate, polycarbonate (PC), polyimide (PI), polypropylene (PP), polyethylene terephthalate (PET), other suitable materials, or a combination thereof. However, the present disclosure is not limited to this.

In this embodiment, the substrate20includes a display area21and a non-display area22. The non-display area22is disposed beside the display area21, and the non-display area22is electrically connected to the flexible circuit structure10.FIG. 2is a partial cross-sectional view taking along the line A-A′ inFIG. 1. As shown inFIG. 2, the flexible circuit structure10includes a flexible substrate11and an insulator, which is an insulating layer121inFIG. 2. The flexible substrate11has a surface110on which a plurality of first pads111are disposed. The insulator is disposed on the flexible substrate11, and is disposed between two adjacent first pads111of the plurality of first pads111.

The material of the flexible substrate11may include, for example, polyimide (PI), polycarbonate (PC), polypropylene (PP), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), acrylic, other suitable materials, or a combination thereof. However, the present disclosure is not limited to this.

The flexible circuit structure10may have a circuit fabricated on the flexible substrate11, and the fabricating process may include, for example, a printing process, a chemical vapor deposition (CVD) process, a lithography process, an etching process, and so on. However, the present disclosure is not limited to this. In addition, the first pad111is a conductive material, which may include, for example, a metal material, such as Au, Cu, Ni, Ag, Ti, Cr, Mo or Al, an alloy material, a conductive metal oxide, other suitable materials, or a combination thereof. However, the present disclosure is not limited to this.

On the flexible substrate11of the flexible circuit structure10, there may be provided active components such as driving chips, or passive components such as resistors, capacitors or inductors. In some embodiments, the flexible substrate11of the flexible circuit structure10may be provided with a driving chip. The driving chip is electrically connected to the circuit board30and the first pads111, and the first pads111are electrically connected to the conductive circuit of the substrate20, so that the driving chip is capable of receiving the signals from the circuit board30and then transmitting the signals to the substrate20through the first pads111. However, the present disclosure is not limited to this.

The material of the insulator may include non-conductive materials. For example, the insulator may include a polymer material, a silicon oxide compound, a silicon nitride compound, a silicon nitride oxide compound, other suitable materials, or a combination thereof. For example, the polymer material may include polyimide (PI), polyethylene (PE), polyethylene terephthalate (PET), polyamide, other suitable materials, or a combination thereof. The silicon oxide compound may include silicon dioxide. The silicon nitride compound may contain Si3N4. The silicon nitride oxide compound may contain Si2N2O. In this embodiment, the material of the insulator is Si3N4. However, the present disclosure is not limited to this.

The shape of the insulator may be a layered shape, columnar shape, tapered shape, or other suitable shapes, or a combination thereof. In some embodiments, the insulator may be disposed between any two adjacent first pads111or on the surface110between any two adjacent first pads111. In some embodiments, the insulator may be disposed at intervals between two adjacent first pads111or on the surface110between two adjacent first pads111. In this embodiment, the insulator includes an insulating layer121, and the insulating layer121is disposed on the surface110between two adjacent first pads111. However, the present disclosure is not limited to this.

When flatten the flexible substrate11, the flexible substrate11extends substantially along the first direction. The normal direction N of the flexible substrate11is substantially perpendicular to the first direction. The angle between the first direction and the normal direction N is between 80 degrees and 100 degrees. The insulating layer121has a first maximum height H1in the normal direction N of the flexible substrate11, and each of the plurality of first pads111has a second maximum height H2in the normal direction N of the flexible substrate11respectively, wherein the first maximum height H1may be less than or equal to the second maximum height H2. In this embodiment, the first maximum height H1is less than the second maximum height H2, but the present disclosure is not limited thereto. The first maximum height H1may 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. As the first maximum height H1is getting less and less, it is easier to maintain the flexibility of the flexible circuit structure. The second maximum height H2may 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 to 2 μm. However, the present disclosure is not limited to this.

In some embodiment, the insulating layer has a first maximum height in a normal direction of the flexible substrate, and one of the plurality of pads has a second maximum height in the normal direction of the flexible substrate, where the first maximum height is less than or equal to the second maximum height.

In some embodiments, the electronic device includes a conductive adhesive40between the flexible circuit structure10and the substrate20. The flexible circuit structure10and the substrate20are electrically connected through the conductive adhesive40, wherein the insulating layer121is disposed between the flexible substrate11and the conductive adhesive40. The conductive adhesive40may include a binder41and a plurality of conductive particles42dispersed in the binder41, wherein the binder41may include a resin adhesive with moisture-proof, heat-resistant, adhesion and insulating functions, such as epoxy resin or polyimide, etc. The conductive particles42may include gold ball particles, such as gold ball particles with a plastic sphere in the center and a nickel layer and a gold layer sequentially coated on the surface of the plastic sphere. The conductive adhesive40may include an anisotropic conductive adhesive or an anisotropic conductive film (ACF). However, the present disclosure is not limited to this.

In some embodiments, the flexible circuit structure10does not have a pixel unit and therefore does not have a display function, while the display area21of the substrate20may include a plurality of thin film transistors and a plurality of pixel units to display images. In some embodiments, the non-display area22of the substrate20may have a plurality of second pads221, and the second pads221may be respectively electrically connected to the thin film transistors or the pixel units. In addition, the second pad221may be a conductive material, for example, including metal materials (such as Au, Cu, Ni, Ag, Ti, Cr, Mo or Al), alloy materials, conductive metal oxides (such as ITO, IZO, ITZO, IGZO or AZO), other suitable materials, or a combination thereof. In addition, the thickness of the second pad221may 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, or between 0.2 μm and 0.4 μm. However, the present disclosure is not limited to this.

In some embodiments, the conductive adhesive40may be placed on the flexible substrate11of the flexible circuit structure10. For example, the conductive adhesive40is placed on the first pad111and the insulating layer121. Then, the substrate20is aligned and placed on the conductive adhesive40, and subsequently the flexible circuit structure10and the substrate20are pressed together so that the flexible circuit structure10and the substrate20are fixed to each other. As a result, the conductive particles42in the conductive adhesive40can be electrically connected to the first pad111and the second pad221, so that signals can be transmitted to the substrate20and inputted to the plurality of pixel units. However, the present disclosure is not limited to this.

In this embodiment, the adhering strength of the conductive adhesive40to the insulating layer121is better than the adhering strength of the conductive adhesive40to the flexible substrate11, so that the adhesion between the flexible circuit structure10and the conductive adhesive40can be improved. In addition, the flexible circuit structure10and the substrate20can be connected through the conductive adhesive40, so as to enhance the adhering strength between the flexible circuit structure10and the substrate20, thereby improving the product reliability of the electronic device.

FIG. 3is a partial cross-sectional view of an electronic device according to another embodiment of the present disclosure. The electronic device of this embodiment is similar to that disclosed inFIG. 2except for the following differences.

In this embodiment, each of the plurality of first pads111has a contact surface1111and two side surfaces1112,1113, and the contact surface1111is opposite to the surface110. The contact surface1111is provided between the two side surfaces1112,1113, and is connected to the two side surfaces1112,1113. In this embodiment, the insulator includes an insulating layer122, and the insulating layer122is disposed on the surface110between two adjacent first pads111and on the two side surfaces1112,1113of the first pad111. In some embodiments, the insulating layer122may be disposed on a partial surface of the surface110between two adjacent first pads111, and extend to a partial surface of one or both of the two side surfaces1112,1113of the first pad111. In some embodiments, the insulating layer122may be disposed on a partial surface of one or both of the two side surfaces1112,1113of the first pad111.

The insulating layer122has a first maximum height H1in the normal direction N of the flexible substrate11, and each of the plurality of first pads111has a second maximum height H2in the normal direction N of the flexible substrate11respectively, wherein the first maximum height H1may be less than or equal to the second maximum height H2.

In some embodiments, the insulating layer has a first maximum height in a normal direction of the flexible substrate, and one of the plurality of pads has a second maximum height in the normal direction of the flexible substrate, where the first maximum height is less than or equal to the second maximum height.

The same or similar components inFIG. 3andFIG. 2will be given the same or similar reference numerals, and the description for those components will be omitted. In this embodiment, the conductive adhesive40may be disposed on the first pad111and the insulating layer122of the flexible circuit structure10, and the conductive adhesive40is disposed between the flexible circuit structure10and the substrate20, wherein the binder41of the conductive adhesive40may be adhered to the insulating layer122on the surface110and the substrate20, respectively, and the conductive particles42in the conductive adhesive40may be electrically connected to the first pad111and the second pad221.

In this embodiment, since the adhering strength of the conductive adhesive40to the insulating layer122is better than the adhering strength of the conductive adhesive40to the flexible substrate11, the flexible circuit structure10and the substrate20can be connected through the conductive adhesive40to improve the adhesion between the flexible circuit structure10and the conductive adhesive40, thereby further enhancing the adhering strength between the flexible circuit structure10and the substrate20. In addition, due to the density of the high-resolution pads being getting higher and higher, the distance between the pads becomes less. In the design of the present disclosure, the insulating layer122extends from the surface of the flexible substrate11to the side surfaces1112,1113of the first pad so as to avoid the short circuit problem caused by the distance between two adjacent first pads111being too small or the density of the conductive particles42being too high, thereby improving the product reliability of the electronic device.

FIG. 4is a partial cross-sectional view of an electronic device according to another embodiment of the present disclosure. The electronic device of this embodiment is similar to that disclosed inFIG. 2except for the following differences.

In this embodiment, the insulator includes an insulating column123. The insulating column123is disposed on the surface110of the flexible substrate11, and is disposed between two adjacent first pads111. The conductive adhesive40is disposed on the surface110, the insulating column123, and the first pad111, and the conductive adhesive40is disposed between the flexible circuit structure10and the substrate20, wherein the binder41in the conductive adhesive40can be adhered to the surface110, the insulating column123and the substrate20, respectively, and the conductive particles42in the conductive adhesive40can electrically connect the first pad111and the second pad221. In this embodiment, the insulating column123can also separate the conductive particles42between the first pads111to avoid a short circuit between the first pads111. In the normal direction N of the flexible substrate11, the insulating column123has a third maximum height H3, and the third maximum height H3may be less than or equal to the second maximum height H2of the first pad111. However, the present disclosure is not limited to this.

In this embodiment, the insulating column123can increase the contact area of the conductive adhesive40and the flexible circuit structure10, and the adhering strength of the conductive adhesive40to the insulating column123is better than the adhering strength of the conductive adhesive40to the flexible substrate11, so as to improve the adhesion of the conductive adhesive40to the flexible circuit structure10, thereby enhancing the product reliability of the electronic device.

FIG. 5is a partial cross-sectional view of an electronic device according to another embodiment of the present disclosure. The electronic device of this embodiment is similar to that disclosed inFIG. 4, except for the following differences.

In this embodiment, the insulator includes an insulating column124, and the insulating column124is disposed on the surface110of the flexible substrate11and is disposed between two adjacent first pads111. In the normal direction N of the flexible substrate11, the insulating column124has a third maximum height H3, and the third maximum height H3is greater than the second maximum height H2of the first pad111. When the flexible substrate11is subject to severe sinking and deformation, a rebounding force will be generated, resulting in that the flexible substrate11and the conductive adhesive40are peeled off. With the insulating column124, a supporting force can be provided during the process of pressing the flexible substrate11and the substrate20so as to prevent the flexible substrate11from sinking and deformation or to prevent the conductive particles42from being excessively deformed.

In addition, in this embodiment, the conductive particles42in the conductive adhesive40have an average particle diameter Ro before being pressed, and the third maximum height H3is less than the sum of the second maximum height H2and the average particle diameter Ro, so as to prevent the insulating column124from hindering the pressing of the flexible substrate11and the substrate20. In the process of pressing the flexible substrate11and the substrate20, the amount of deformation of the conductive particle42between the first pad111and the second pad221is 30%-70%, that is, after being pressed, the pressed particle diameter Rd of the conductive particle42is 30%-70% of the average particle diameter Ro. In some embodiments, the amount of deformation of the conductive particle42between the first pad111and the second pad221may be between 30%-70%, 30%-60% or 30%-50%. If the conductive particle42is excessively pressed, the conductive particle42will be damaged, and thus the amount of deformation of the conductive particle42should not be too large. Therefore, the third maximum height H3may be between the second maximum height H2and the sum of the second maximum height H2and 30%-70% of the average particle diameter Ro. In this embodiment, the average particle diameter Ro can 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 to 2 μm. However, the present disclosure is not limited to this.

In this embodiment, the insulating column124not only provides a supporting force during the pressing process to prevent the flexible substrate11from sinking and deformation or to prevent the conductive particles42from being excessively deformed, but also increases the contact area between the conductive adhesive40and the flexible circuit structure10. Furthermore, the adhering strength of the conductive adhesive40to the insulating column124is better than that of the conductive adhesive40to the flexible substrate11, which can improve the adhesion of the conductive adhesive40to the flexible circuit structure10, thereby enhancing the product reliability of the electronic device.

FIG. 6is a partial cross-sectional view of an electronic device according to another embodiment of the present disclosure. The electronic device of this embodiment is similar to that disclosed inFIG. 2orFIG. 5, except for the following differences.

In this embodiment, the insulator includes an insulating layer125similar to that shown inFIG. 2and an insulating column126similar to that shown inFIG. 5. The insulating layer125is disposed on all of the surface110between two adjacent first pads111. The insulating column126is disposed on the insulating layer125and between two adjacent first pads111. The conductive adhesive40is disposed on the insulating layer125, the insulating columns126, and the first pads111. The conductive adhesive40is disposed between the flexible circuit structure10and the substrate20, wherein the binder41in the conductive adhesive40can be adhered to the insulating layer125, the insulating column126and the substrate20, respectively, and the conductive particles42in the conductive adhesive40can electrically connect the first pad111and the second pad221. However, the present disclosure is not limited to this. In some embodiments, the insulating layer125and the insulating columns126can be manufactured in the same process. In some embodiments, the insulating layer125and the insulating columns126can be manufactured in different processes. The insulating layer125and the insulating column126can be made of the same material or different materials. For example, the insulating layer125may be made of an inorganic material, and the insulating column126may be made of an organic material, while they are manufactured in different processes. Alternatively the insulating layer125and the insulating column126are both made of organic materials, and they are manufactured in different processes or in the same process. In some embodiments, the insulating layer125and the insulating column126are made of the same material. However, the present disclosure is not limited to this. InFIG. 6, the elements that are the same as or similar to those in the aforementioned embodiments will have the same or similar reference numerals, and their description will be omitted. The insulating layer125may have a first maximum height H1, and the insulating column126may have a fourth maximum height H4, wherein the sum of the first maximum height H1and the fourth maximum height H4(that is, the maximum height of the insulator in the normal direction N of the flexible substrate11) is greater than the second maximum height H2of the first pad111. In addition, in this embodiment, before being pressed, the conductive particles42in the conductive adhesive40have an average particle size Ro, and the sum of the first maximum height H1and the fourth maximum height H4is less than the sum of the second maximum height H2and the average particle diameter Ro. In the process of pressing the flexible substrate11and the substrate20, the amount of deformation of the conductive particle42between the first pad111and the second pad221is 30%-70%, that is, after being pressed, the pressed particle diameter Rd of the conductive particle42is 30%-70% of the average particle diameter Ro. In some embodiments, the amount of deformation of the conductive particle42between the first pad111and the second pad221may be between 30%-70%, 30%-60%, or 30%-50%. If the conductive particles42are excessively pressed, the conductive particles42will be damaged, and thus the amount of deformation of the conductive particle42should not be too large. Therefore, the sum of the first maximum height H1and the fourth maximum height H4may be between the second maximum height H2and the sum of the second maximum height H2and 30%-70% of the average particle diameter Ro. However, the present disclosure is not limited to this.

It can be understood that this embodiment can achieve the effect ofFIG. 2orFIG. 5of the aforementioned embodiments, and thus a detailed description for the repeated portion is deemed unnecessary.

FIG. 7is a partial cross-sectional view of an electronic device according to another embodiment of the present disclosure. The electronic device of this embodiment is similar to that disclosed inFIG. 3orFIG. 5, except for the following differences.

In this embodiment, the insulator includes an insulating layer127similar to that shown inFIG. 3and an insulating column128similar to that shown inFIG. 5. The insulating layer127is disposed on all of the surface110between two adjacent first pads111and on the two side surfaces1112,1113of the first pad111. The insulating column128is arranged on the insulating layer127and between two adjacent first pads111. The conductive adhesive40is disposed on the insulating layer127, the insulating columns128and first pads111, and the conductive adhesive40is disposed between the flexible circuit structure10and the substrate20, wherein the binder41in the conductive adhesive40can be adhered to the insulating layer127, the insulating column128, and the substrate20, respectively, and the conductive particles42in the conductive adhesive40can be electrically connected to the first pad111and the second pad221. However, the present disclosure is not limited to this. In some embodiments, the insulating layer127and the insulating column128may be manufactured in the same process. In some embodiments, the insulating layer127and the insulating column128may be manufactured in different processes. The insulating layer127and the insulating column128may be made of the same material or different materials. For example, the insulating layer127may be made of an inorganic material, and the insulating column128may be made of an organic material, while they are manufactured in different processes. Alternatively, the insulating layer127and the insulating column128are both made of organic materials, and they are manufactured in different processes or the same process. In some embodiments, the insulating layer127and the insulating column128are made of the same material. However, the present disclosure is not limited to this. InFIG. 7, elements that are the same as or similar to those in the aforementioned embodiments will be given the same or similar reference numerals, and their description will be omitted.

It can be understood that this embodiment can achieve the effect ofFIG. 3orFIG. 5of the aforementioned embodiments, and thus a detailed description for the repeated portion is deemed unnecessary.

The aforementioned embodiments describe in detail the connection of the flexible circuit structure10to the substrate20and the circuit board30, but the present disclosure is not limited thereto. Any electronic component that transmits signals through the pads can be connected with the flexible circuit structure10of the present disclosure for signal transmission.

Although the present disclosure has been explained in relation to its embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the disclosure as hereinafter claimed.