TW202437819A - Circuit board structure - Google Patents

Abstract

A circuit board structure includes a first rigid board, a second rigid board and a first flexible plate. The first rigid board includes a first glass substrate and a first conductive wire, and the second rigid board includes a second glass substrate and a second conductive wire. The first flexible board is connected to the first rigid board and the second rigid board, and the first flexible board includes the first flexible glass substrate and the first connecting wire. The first glass substrate, the second glass substrate and the first flexible glass substrate are integrally formed. The first conductive wire, the second conductive wire and the first connecting wire are electrically connected with each other. When the first flexible board is bent, the radius of curvature of the first flexible board is 0.5 mm to 5 mm.

Description

Circuit board structure

The present invention relates to a circuit board structure, and more particularly to a rigid-flexible circuit board having a glass substrate.

A rigid-flex circuit board is a circuit board structure that includes a flexible circuit board and a rigid circuit board that are connected to each other. It has both the flexibility of a flexible circuit board and the hardness of a rigid circuit board.

A conventional rigid-flex circuit board includes a rigid substrate and a flexible substrate connected to each other, wherein the material of the rigid substrate may be epoxy resin combined with glass fiber, and the material of the flexible substrate may be polyimide (PI), modified polyimide (MPI) or liquid crystal polymer (LCP). In order to electrically connect the lines of the rigid substrate and the flexible substrate, a hot bar welding method is generally used to weld the conductive pads of the rigid substrate to the conductive pads of the flexible substrate; or an anisotropic conductive film (ACF) is used to bond the rigid substrate and the flexible substrate, so that the conductive pads of the rigid substrate can be electrically connected to the corresponding conductive pads of the flexible substrate.

However, since the bonding process of the rigid board substrate and the flexible board substrate involves the alignment of the welding area and hot pressing bonding, and the rigid board substrate and the flexible board substrate are usually opaque or only slightly translucent, the process steps are complicated and the process cost is high, and poor welding (for example, alignment deviation or poor adhesion between substrates) is prone to occur.

Therefore, it is necessary to provide an improved circuit board structure to overcome the technical problems faced by the prior art.

In view of this, the present invention provides a circuit board structure that overcomes the technical problems faced by the prior art.

According to an embodiment of the present invention, a circuit board structure is provided, including a first rigid board, a second rigid board and a first bendable board. The first rigid board includes a first glass substrate and a first conductive line, and the second rigid board includes a second glass substrate and a second conductive line. The first bendable board is connected to the first rigid board and the second rigid board, and the first bendable board includes a first bendable glass substrate and a first connecting line. The first glass substrate, the second glass substrate and the first bendable glass substrate are an integrally formed structure. The first conductive line, the second conductive line and the first connecting line are electrically connected to each other. When the first bendable board is bent, the radius of curvature of the first bendable board is 0.5 mm to 5 mm.

According to another embodiment of the present invention, a circuit board structure is provided, including a first rigid board, a second rigid board, a bendable board, an electronic component and an adhesive layer. The first rigid board includes a first glass substrate and a first conductive line, the first conductive line is arranged on the surface of the first glass substrate, the first glass substrate includes a conductive through hole, and the conductive through hole is electrically connected to the first conductive line. The second rigid board includes a second glass substrate and a second conductive line, the second conductive line is arranged on the surface of the second glass substrate. The bendable board is connected to the first rigid board and the second rigid board, the bendable board includes a bendable glass substrate and a connecting line, the connecting line is arranged on the surface of the bendable glass substrate, and the curvature radius of the first bendable board is 0.5 mm to 5 mm. The electronic component is arranged between the first rigid board and the second rigid board, and is welded to the first conductive line or the second conductive line. The adhesive layer is disposed between the first rigid board and the second rigid board to fix the first rigid board to the second rigid board. The first glass substrate, the second glass substrate and the bendable glass substrate are an integrally formed structure, and the first conductive line, the second conductive line and the connecting line are electrically connected to each other.

In order to enable a person skilled in the art to further understand the present invention, several preferred embodiments of the present invention are listed below, and the attached drawings are used to explain in detail the composition and intended effects of the present invention. Furthermore, a person skilled in the art to which the present invention belongs can also refer to the following embodiments and replace, reorganize, and mix the features of several different embodiments to complete other embodiments without departing from the spirit of the present invention.

Please refer to FIG. 1, which is a three-dimensional schematic diagram of a circuit board structure of an embodiment of the present invention. As shown in FIG. 1, the circuit board structure 10 is a rigid-flexible circuit board, including a first rigid board 12, a first bendable board 14, a second rigid board 16, and a second bendable board 18. The first rigid board 12, the first bendable board 14, the second rigid board 16, and the second bendable board 18 are connected to each other and include an integrally formed glass substrate 110, such as a first glass substrate 120, a second glass substrate 140, a third glass substrate 160, and a fourth glass substrate 180. The thickness of the first glass substrate 120, the second glass substrate 140, the third glass substrate 160 and the fourth glass substrate 180 is less than 200 μm, for example, 100 μm to 200 μm, and the thickness of the second glass substrate 140 and the fourth glass substrate 180 may be less than the thickness of the first glass substrate 120 and the third glass substrate 160. The glass substrate 110 is a light-transmitting material that can at least allow light with a wavelength of 350 nm to 800 nm to pass through, that is, the ratio of the light intensity of the transmitted light passing through the glass substrate 110 to the incident light incident on the glass substrate 110 is greater than 80%, or 100%.

The first bendable plate 14 and the second bendable plate 18 include a plurality of etched areas 148, 188 for increasing the flexibility of the first bendable plate 14 and the second bendable plate 18. According to different requirements, the etched areas 148, 188 may be recessed portions or through holes. The top view profile of the etched areas 148, 188 may be a circular or elliptical geometric shape including curves, rather than a polygon or other geometric shape with obvious angles. Therefore, when the first bendable plate 14 and the second bendable plate 18 are bent, stress concentration on specific edges of the etched areas 148, 188 can be avoided, thereby increasing the flexibility of the first bendable plate 14 and the second bendable plate 18. According to an embodiment of the present invention, when the first bendable plate 14 or the second bendable plate 18 is bent, the radius of curvature of the first bendable plate 14 or the second bendable plate 18 is 0.5 mm to 5 mm.

The two opposite surfaces of the glass substrate 110, the first surface 110-1 and the second surface 110-2, can be respectively provided with circuit structures so that electronic signals can be transmitted from one area to another area. For example, an electronic signal can be generated by an electronic component disposed on the first rigid board 12 and transmitted to another electronic component disposed on the second rigid board 16 through the first bendable board 14.

According to an embodiment of the present invention, the first rigid board 12 includes a circuit structure composed of a first conductive line 122 and a conductive pad 124. The circuit structure can be formed by etching a metal layer, such as a copper foil layer, disposed on the glass substrate 110 to form a circuit structure with a specific design layout. Similarly, the second rigid board 16 includes a circuit structure composed of a second conductive line 162 and a conductive pad 164. The circuit structure of the first rigid board 12 and the second rigid board 16 is not limited to being formed only on the first surface 110-1 of the glass substrate 110, and can also be formed on the second surface 110-2 of the glass substrate 110, wherein the circuit structure formed on the first surface 110-1 can be referred to as a front-side circuit structure, and the circuit structure formed on the second surface 110-2 can be referred to as a back-side circuit structure. Since the first rigid board 12 and the second rigid board 16 also include a plurality of conductive vias 128, the front-side circuit structure can be electrically connected to the back-side circuit structure through the conductive vias 128.

The first bendable plate 14 includes a circuit structure composed of a first connection line 142 and a conductive pad 144. The circuit structure can be formed by etching a metal layer, such as a copper layer, disposed on the glass substrate 110 to form a circuit structure with a specific layout design. Similarly, the second bendable plate 18 includes a circuit structure composed of a second connection line 182 and a conductive pad 184. The circuit structure of the first connecting circuit 142 and the second connecting circuit 182 is not limited to being formed only on the first surface 110-1 of the glass substrate 110, and can also be formed on the second surface 110-2 of the glass substrate 110, wherein the circuit structure formed on the first surface 110-1 can be referred to as a front-side circuit structure, and the circuit structure formed on the second surface 110-2 can be referred to as a back-side circuit structure (not shown).

Depending on different requirements, the circuit structure of the circuit board structure 10 can have a variety of design layouts. According to an embodiment of the present invention, a conductive pad 124 located on the front side circuit structure of the first rigid board 12 is electrically connected to the first conductive line 122-1, and is sequentially electrically connected to the first connection line 142-1 of the first bendable board 14, the second conductive line 162-1 of the second rigid board 16, and the conductive through hole 168 of the second rigid board 16, and is further electrically connected to the back side circuit structure.

According to an embodiment of the present invention, a conductive pad 124 located on the front side circuit structure of the first rigid board 12 is sequentially electrically connected to the first conductive circuit 122-2, the conductive through hole 128 of the first rigid board 12, and further electrically connected to the back side circuit structure.

According to an embodiment of the present invention, a conductive pad 124 located on the front side circuit structure of the first rigid board 12 is sequentially electrically connected to the first conductive circuit 122-2, the conductive through hole 128 of the first rigid board 12, and further electrically connected to the back side circuit structure.

According to an embodiment of the present invention, a conductive pad 124 located at the front side circuit structure of the first rigid board 12 is sequentially electrically connected to the first conductive circuit 122-3, and sequentially electrically connected to the first connecting circuit 142-2 of the first bendable board 14, the second conductive circuit 162-3 of the second rigid board 16, and the second connecting circuit 182-1 of the second bendable board 18.

According to an embodiment of the present invention, a certain conductive via 128 located in the front-side circuit structure of the first rigid board 12 is electrically connected to another conductive via 128 through the first conductive line 122-4, and further electrically connected to the back-side circuit structure.

According to one embodiment of the present invention, a conductive pad 124 located on the front side circuit structure of the first rigid board 12 is electrically connected to the first conductive circuit 122-5, the first connecting circuit 142-3 of the first bendable board 14, the second conductive circuit 162-4 of the second rigid board 16, the second connecting circuit 182-2 of the second bendable board 18 in sequence, and finally electrically connected to the conductive pad 184 of the second bendable board 18.

According to one embodiment of the present invention, a conductive pad 124 located on the front side circuit structure of the first rigid board 12 is electrically connected to the first conductive circuit 122-6 and the conductive through hole 128 of the first rigid board 12 in sequence, and is electrically connected to the conductive through hole 168 and the second conductive circuit 162-5 of the second rigid board 16 via the back side circuit structure (not shown), and finally is electrically connected to the conductive pad 164 of the second rigid board 16.

According to an embodiment of the present invention, a conductive pad 124 of the front circuit structure of the first rigid board 12 is electrically connected to a conductive pad 144 of the first bendable board 14 via a first conductive circuit 122 - 7 .

According to an embodiment of the present invention, the conductive pads 164 of the front-side circuit structure of the second rigid board 16 are electrically connected to each other through the second conductive circuit 162-2, and further electrically connected to the conductive through-hole 168 of the second rigid board 16, and further electrically connected to the back-side circuit structure.

The present invention uses an integrally formed glass substrate 110 to manufacture interconnected hard and soft boards (such as the aforementioned bendable board), which not only avoids the complicated and costly welding process, but also avoids the problem of misalignment between substrates or poor adhesion between substrates. In addition, since the glass substrate 110 is light-transmissive, even if the bendable board needs to be welded to other substrates, it is easy to align the positions of the substrates without misalignment.

FIG. 2 is a schematic cross-sectional view of an embodiment of the present invention along the section line A-A'. As shown in FIG. 2, the thicknesses of the first hard plate 12, the first bendable plate 14, and the second hard plate 16 are substantially the same, and the etched portion 148 in the first bendable plate 14 is a through hole 149 that penetrates the glass substrate 110. The through hole 149 may be formed by wet etching, laser etching, or laser etching combined with wet etching, but is not limited thereto.

FIG. 3 is a schematic cross-sectional view of an embodiment of the present invention along the section line B-B'. As shown in FIG. 3, the conductive via 128 in the first rigid board 12 penetrates the glass substrate 110, and the conductive via 128 electrically connects the front-side circuit structure 121 to the back-side circuit structure 123. Compared with the resin substrate, the glass substrate 110 has higher surface flatness, heat resistance and thermal conductivity, so the size and spacing of the circuit structure and the conductive via disposed on the glass substrate 110 can be easily miniaturized. According to an embodiment of the present invention, the circuit board structure 10 can be used as a carrier substrate of a Micro LED and as a component of a Micro LED display by adjusting the sizes and spacings of the front-side wiring structure 121, the back-side wiring structure 123, and the conductive vias 128.

Figure 4 is a schematic cross-sectional view of an embodiment of the present invention along the section line C-C’. As shown in Figure 4, the conductive pads 124 and 127 on the two opposite surfaces 110-1 and 110-2 of the first hard board 12 can be electrically connected to the corresponding electronic components 204-1 and 204-2, respectively. The types of the electronic components 204-1 and the electronic components 204-2 can be the same or different, depending on actual needs. The middle layer 202 between the electronic components 204-1, 204-2 and the corresponding conductive pads 124 and 127 can be a conductive metal or anisotropic conductive glue, so that electrical connections are generated between the electronic components 204-1, 204-2 and the conductive pads 124 and 127.

According to different embodiments of the present invention, the etched portion 148, 188 of the first bendable plate 14 or the second bendable plate 18 is not limited to the through hole 149 shown in FIG. 2, but may also be a recessed portion 147 as shown in FIG. 5 or FIG. 6.

As shown in FIG. 5 , the etched portion 148 in the first bendable plate 14 does not penetrate the glass substrate 110 , and thus takes the form of a recessed portion 147 .

As shown in FIG. 6 , similar to FIG. 5 , the etched portion 148 in the first bendable plate 14 also presents the shape of the recessed portion 147. However, the thickest thickness of the glass substrate 140 of the first bendable plate 14 is less than the thickness of the first hard plate 12 and the second hard plate 16. According to one embodiment, in order to form the structure shown in FIG. 6 , before forming the recessed portion 147, the overall thickness of the first bendable plate 14 may be thinned, and then further etching may be performed to form the recessed portion 147 in the first bendable plate 14.

According to different embodiments of the present invention, the contour and arrangement layout of the etched portion 148, 188 of the first bendable plate 14 or the second bendable plate 18 are not limited to the contour and arrangement layout shown in FIG. 1, but may also be the contour and arrangement layout shown in FIG. 7 or FIG. 8.

As shown in FIG. 7 , each etched portion 148 in the first bendable plate 14 is still elliptical, however, the long axis direction of each etched portion 148 shown in FIG. 7 is perpendicular to the long axis direction of each etched portion 148 shown in FIG. 1 . According to different needs, the long axis direction of each etched portion 148 can be adjusted arbitrarily, and is not limited to the embodiment disclosed in the present invention.

As shown in FIG. 8 , each etched portion 148 in the first bendable plate 14 is still elliptical, however, the first bendable plate 14 includes one row but multiple columns of etched portions 148, rather than multiple rows and multiple columns of etched portions 148. In addition, the long axis direction of each etched portion 148 shown in FIG. 8 is perpendicular to the long axis direction of each etched portion 148 shown in FIG. 1 . According to different needs, the long axis direction of each etched portion 148 can be adjusted arbitrarily, and is not limited to the embodiment disclosed in the present invention.

According to an embodiment of the present invention, the first bendable plate 14 can be bent, and the first hard plate 12 can be fixed to the second hard plate 16 using an adhesive layer to form a structure similar to that shown in FIG. 9 .

As shown in FIG. 9 , the circuit board structure 20 is similar to the circuit board structure 10 shown in FIG. 1 , with the main difference being that the first rigid board 12 in the circuit board structure 20 is fixed to the second rigid board 16 by the adhesive layer 208 and the radius of curvature r of the first bendable board 14 is 0.5 mm to 5 mm. The adhesive layer 208 does not necessarily fill all the space between the first rigid board 12 and the second rigid board 16, but may leave a cavity 212 adjacent to the first bendable board 14. The electronic component 204 is disposed between the first rigid board 12 and the second rigid board 16 and is covered by the adhesive layer 208. The electronic component 204 can transmit or receive electrical signals through the circuit structure 210, wherein the circuit structure is similar to the circuit structure described in the embodiment of FIG. 1, and will not be described in detail here. According to an embodiment of the present invention, the adhesive layer 208 can be an optical clear adhesive (OCA), so that light can penetrate the adhesive layer 208. It should be noted that the number of hard boards, the number of bending boards, the position and number of electronic components 204, and the configuration and number of layers of the circuit structure 210 of the circuit board structure 20 shown in FIG. 9 are only examples, which can be adjusted according to actual needs. The above is only a preferred embodiment of the present invention, and all equal changes and modifications made according to the scope of the patent application of the present invention should be covered by the present invention.

10, 20: Circuit board structure 12: First rigid board 14: First bendable board 16: Second rigid board 18: Second bendable board 110: Glass substrate 110-1: First surface 110-2: Second surface 120: First glass substrate 121: Front circuit structure 122: First conductive circuit 122-1~122-7: First conductive circuit 123: Back circuit structure 124: Conductive pad 127: Conductive pad 128: Conductive through hole 140: Second glass substrate 142: First connecting circuit 142-2-1~142-4: First connecting circuit 144: Conductive pad 147: Recessed portion 148: Etching area 149: Through hole 160: Third glass substrate 162: Second conductive line 162-1~162-5: Second conductive line 164: Conductive pad 180: Fourth glass substrate 182: Second connecting line 182-1~182-2: Second connecting line 184: Conductive pad 188: Etching area 202: Intermediate layer 204: Electronic component 204-1, 204-2: Electronic component 208: Adhesive layer 212: Cavity r: Radius of curvature

FIG. 1 is a three-dimensional schematic diagram of a circuit board structure of an embodiment of the present invention. FIG. 2 is a cross-sectional schematic diagram of an embodiment of the present invention along the section line A-A’ of FIG. 1. FIG. 3 is a cross-sectional schematic diagram of an embodiment of the present invention along the section line B-B’ of FIG. 1. FIG. 4 is a cross-sectional schematic diagram of an embodiment of the present invention along the section line C-C’ of FIG. 1. FIG. 5 is a cross-sectional schematic diagram of a circuit board structure of another embodiment of the present invention. FIG. 6 is a cross-sectional schematic diagram of a circuit board structure of another embodiment of the present invention. FIG. 7 is a top view schematic diagram of a circuit board structure of another embodiment of the present invention. FIG. 8 is a top view schematic diagram of a circuit board structure of another embodiment of the present invention. FIG. 9 is a cross-sectional schematic diagram of a circuit board structure of another embodiment of the present invention.

10: Circuit board structure

12: The first hard board

14: The first bendable plate

16: Second hard board

18: Second bendable plate

110: Glass substrate

110-1: First surface

110-2: Second surface

120: First glass substrate

122: First conductive line

122-1~122-7: First conductive line

124: Conductive pad

128: Conductive vias

140: Second glass substrate

142: First connection line

142-2-1~142-4: First connection line

144: Conductive pad

148: Etching area

160: Third glass substrate

162: Second conductive line

162-1~162-5: Second conductive line

164: Conductive pad

180: Fourth glass substrate

182: Second connection line

182-1~182-2: Second connection line

184: Conductive pad

188: Etching area

Claims (10)

A circuit board structure includes: A first rigid board, including a first glass substrate and a first conductive line, wherein the first conductive line is arranged on the surface of the first glass substrate; A second rigid board, including a second glass substrate and a second conductive line, wherein the second conductive line is arranged on the surface of the second glass substrate; and A first bendable board, connected to the first rigid board and the second rigid board, wherein the first bendable board includes a first bendable glass substrate and a first connecting line, wherein the first connecting line is arranged on the surface of the first bendable glass substrate; wherein the first glass substrate, the second glass substrate and the first bendable glass substrate are an integrally formed structure, wherein the first conductive line, the second conductive line and the first connecting line are electrically connected to each other, Wherein, when the first bendable plate is bent, the radius of curvature of the first bendable plate is 0.5 mm to 5 mm. The circuit board structure as described in claim 1, wherein the thickness of the first glass substrate and the second glass substrate is 50 μm to 200 μm. A circuit board structure as described in claim 1, wherein the first glass substrate and the second glass substrate respectively include a plurality of conductive through holes. A circuit board structure as described in claim 1, wherein the first bendable plate includes a plurality of through holes, and the top view contour of each through hole includes a curve. The circuit board structure as described in claim 1 further comprises: At least one electronic component soldered to one of the first conductive line, the second conductive line and the first connecting line. A circuit board structure as described in claim 5, wherein the at least one electronic component is soldered to the first conductive line, and when the first bendable plate is bent, the at least one electronic component is located between the first glass substrate and the second glass substrate. A circuit board structure as described in claim 1, wherein the first rigid board further comprises a back-side conductive circuit disposed on the other surface of the first glass substrate and disposed opposite to the first conductive circuit, wherein the back-side conductive circuit is electrically connected to the first conductive circuit via the conductive through holes. The circuit board structure as described in claim 7 further comprises: A plurality of electronic components, respectively disposed on the surface and the other surface of the first glass substrate, and respectively soldered to the first conductive line and the back conductive line. The circuit board structure as described in claim 1 further comprises: A second bendable plate, comprising a second bendable glass substrate and a second connecting line, wherein the second connecting line is arranged on the surface of the second bendable glass substrate, and the second bendable plate and the first bendable plate are respectively located on different sides of the second glass substrate, wherein the second bendable glass substrate and the first glass substrate are an integrally formed structure, wherein when the second bendable plate is bent, the curvature radius of the second bendable plate is 0.5 mm to 5 mm. A circuit board structure, comprising: A first rigid board, comprising a first glass substrate and a first conductive line, the first conductive line is arranged on the surface of the first glass substrate, the first glass substrate comprises a plurality of conductive through holes, and the conductive through holes are electrically connected to the first conductive line; A second rigid board, comprising a second glass substrate and a second conductive line, the second conductive line is arranged on the surface of the second glass substrate; A bendable board, connected to the first rigid board and the second rigid board, the bendable board comprises a bendable glass substrate and a connecting line, the connecting line is arranged on the surface of the bendable glass substrate, and the curvature radius of the first bendable board is 0.5 mm to 5 mm; At least one electronic component, arranged between the first rigid board and the second rigid board, and soldered to the first conductive line or the second conductive line; and An adhesive layer is disposed between the first rigid board and the second rigid board to fix the first rigid board to the second rigid board, wherein the first glass substrate, the second glass substrate and the bendable glass substrate are an integrally formed structure, wherein the first conductive line, the second conductive line and the connecting line are electrically connected to each other.

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