CN105826353A - Chip on film and display device - Google Patents

Abstract

The present invention provides a chip-on-chip film, which includes a flexible circuit board, and the flexible circuit board includes a conductive layer, and the conductive layer includes a first bonding area located at a first end of the conductive layer and a first bonding area located at a second end of the conductive layer. Two binding areas, the first binding area is used for binding the display substrate, the second binding area is used for binding the printed circuit board, the first binding area and the second binding area are respectively located on two opposite surfaces of the conductive layer. Correspondingly, the present invention also provides a display device. The invention can reduce the overall thickness of the display device and prevent chips on the chip-on-chip film from being squeezed.

Description

Chip-on-chip film and display device

technical field

The invention relates to the field of display technology, in particular to a chip-on-chip film and a display device.

Background technique

The chip-on-chip technology (ChipOnFlex, or, ChipOnFilm, COF) is a technology of bonding the pads on the driver chip and the pins on the flexible circuit board by thermal compression. FIG. 1 is a schematic structural view of a chip-on-chip film in the prior art. A flexible circuit board 20 includes a base 21, a metal layer 22, and a paint film 23. The paint film 23 exposes both ends of the metal layer 22, and the exposed two parts are respectively connected to the display substrate. 30 is bound to the printed circuit board 40, as shown in FIG. After the side of the display substrate 30 away from the light emitting direction is bent, as shown in FIG. 3 , the following problems are likely to be caused: the driver chip 10 on the flexible circuit board 20 is exposed to the outside and is easily squeezed, which causes the frame of the display device The width increases; the component 41 on the printed circuit board 40 and the binding area of the printed circuit board 40 are located on different sides, and when the printed circuit board 40 and the flexible circuit board 20 are bound, the component 41 is easily crushed; in addition, the flexible circuit board After 20 is bent, the printed circuit board 40 is located above the flexible circuit board 20 , so that when the bending degree of the flexible circuit board 20 is constant, the overall thickness of the display device is relatively large.

Contents of the invention

The object of the present invention is to provide a chip-on-chip film and a display device, so that the thickness of the display device using the chip-on-chip film can be reduced.

In order to achieve the above object, the present invention provides a chip-on-film, which includes a flexible circuit board, the flexible circuit board includes a conductive layer, and the conductive layer includes a first bonding area at the first end of the conductive layer and a first binding area at the first end of the conductive layer. The second binding area at the second end of the layer, the first binding area is used for binding the display substrate, the second binding area is used for binding the printed circuit board, the first binding area and the first binding area The two binding regions are respectively located on two opposite surfaces of the conductive layer.

Preferably, the flexible circuit board further includes a base and an insulating layer, the base, the conductive layer, and the insulating layer are sequentially stacked along the thickness direction of the base, and the first end of the conductive layer exceeds the The base, the second end of the conductive layer is beyond the insulating layer, the surface of the portion of the conductive layer that is beyond the base and away from the insulating layer is formed as the first binding region, and the conductive layer The surface of the portion beyond the insulating layer that is away from the substrate is formed as the second binding region.

Preferably, the COF further includes a driver chip fixed on the conductive layer, the conductive layer includes two conductive parts arranged at intervals, the first binding area and the second binding area are respectively Formed on the two conductive parts, the input end and the output end of the driving chip are respectively connected to the two conductive parts, the driving chip and the insulating layer are located on the same side of the conductive layer, the An opening corresponding to the driving chip is disposed on the insulating layer, and the driving chip is disposed in the opening.

Preferably, the end surface of the first end of the conductive layer is flush with the end surface of the insulating layer, and the end surface of the second end of the conductive layer is flush with the end surface of the base.

Preferably, the material forming the insulating layer and the material forming the substrate are each independently selected from any one of polyphenylene sulfide, polyphenylene ester, polybenzimidazole, and polyphenylene diphenylsiloxane.

Preferably, the insulating layer is formed of the same material as the substrate.

Correspondingly, the present invention also provides a display device, including a display substrate, a printed circuit board, and the above-mentioned chip-on-chip film provided by the present invention, the display substrate includes a display area and a lead area located around the display area, and the flexible The first binding area of the circuit board is bound to the lead area of the display substrate, the second binding area of the flexible circuit board is bound to the printed circuit board, and the printed circuit board is fixedly arranged on the display substrate. The side of the substrate away from the light emitting direction.

Preferably, the display substrate includes a base substrate and a plurality of bottom-emission organic light emitting diodes disposed on the base substrate, and the display device further includes an encapsulation layer disposed opposite to the display substrate.

Preferably, the encapsulation layer is conductive, and a low-level input terminal is provided on the printed circuit board, and the low-level input terminal is electrically connected to the encapsulation layer.

Preferably, conductive glue is provided between the printed circuit board and the encapsulation layer to electrically connect the low-level input terminal on the printed circuit board to the encapsulation layer.

In the present invention, since the first binding area and the second binding area are respectively located on two opposite surfaces of the conductive layer, the unbent flexible circuit board is connected to the display substrate and the printed circuit board respectively. After binding, the display substrate is located below the conductive layer, and the printed circuit board is located above the conductive layer. For bottom-emission organic light-emitting display devices, after the flexible circuit board is bent toward the backlight side of the display substrate, the second binding area faces the display substrate. substrate, so that the printed circuit board is located between the second bonding area and the display substrate. Therefore, when the flexible circuit board in the present invention is bent to the same extent as the flexible circuit board in the prior art, the present invention can enable the application The thickness of the display device of the flexible circuit board is thinner; and, since the components on the printed circuit board and the bonding area of the printed circuit board are located on the same side of the printed circuit board, when the printed circuit board and the flexible circuit board are bonded and connected, The phenomenon that parts on the printed circuit board are crushed can be reduced, and the yield rate of products is improved.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, together with the following specific embodiments, are used to explain the present invention, but do not constitute a limitation to the present invention. In the attached picture:

FIG. 1 is a schematic structural view of a chip-on-chip film in the prior art;

Fig. 2 is a schematic diagram of binding of an unbent chip-on-chip film to a display substrate and a printed circuit board in the prior art;

Fig. 3 is a schematic diagram of the state after the chip-on-chip film in Fig. 2 is bent;

4 is a schematic structural view of a chip-on-film provided in an embodiment of the present invention;

Fig. 5 is a schematic diagram of binding an unbent chip-on-chip film with a display substrate and a printed circuit board in an embodiment of the present invention;

Fig. 6 is a schematic diagram of the state after the COF in Fig. 5 is bent;

FIG. 7 is a schematic structural diagram of a display device provided in an embodiment of the present invention.

Wherein, reference signs are: 10, chip; 20, flexible circuit board in the prior art; 21, substrate in the prior art; 22, metal layer; 23, paint film; 30, display substrate; 31, substrate Substrate; 32. Bottom emission type organic light emitting diode; 40. Printed circuit board; 41. Components of printed circuit board; 50. Packaging layer; 60. Flexible circuit board in the present invention; 61. Substrate in the present invention; 62. Conductive layer; 621, first binding area; 622, second binding area; 62a, conductive part; 63, insulating layer; 70, conductive glue; 80, adhesive glue.

detailed description

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

As one aspect of the present invention, a chip-on-film is provided. As shown in FIG. 4 and FIG. The first bonding region 621 at the first end of the layer 62 and the second bonding region 622 at the second end 62 of the conductive layer, the first bonding region 621 is used for bonding (bonding) the display substrate 30, the second bonding region The region 622 is used for bonding the printed circuit board 40 , and the first bonding region 621 and the second bonding region 622 are respectively located on two opposite surfaces of the conductive layer 62 .

In the present invention, since the first bonding region 621 and the second bonding region 622 are respectively located on two opposite surfaces of the conductive layer 62, the unbent flexible circuit board 60 is connected to the display substrate 30 and the printed circuit board respectively. After the boards 40 are bound, the display substrate 30 is located below the conductive layer 62, and the printed circuit board 40 is located above the conductive layer 62. For a bottom-emission organic light-emitting display device, after the flexible circuit board 60 is bent toward the backlight side of the display substrate, The second binding area 622 faces the display substrate 30, so that the printed circuit board 40 is located between the second binding area 622 and the display substrate 30. Therefore, when the flexible circuit board 60 in the present invention and the flexible circuit board 60 in the prior art When the bending degree of the circuit board 20 is the same, the present invention can make the thickness of the display device using the flexible circuit board 20 thinner; 40 on the same side, when the printed circuit board 40 and the flexible circuit board 60 are bound and connected, the phenomenon of parts 41 being crushed on the printed circuit board 40 can be reduced, and the yield rate of the product is improved; in addition, when flip chip When the driving chip 10 and the second binding region 622 of the thin film are located on the same side of the conductive layer 62, after the flexible circuit board 60 is bent, the driving chip 10 is located inside the flexible circuit board 60, thereby preventing the driving chip 10 from being squeezed , and there is no need to reserve space for the driver chip 10 at the frame position of the display device, which facilitates the realization of a narrow frame.

Specifically, as shown in FIG. 4 , the flexible circuit board 60 also includes a base 61 and an insulating layer 63. The base 61, the conductive layer 62, and the insulating layer 63 are stacked sequentially along the thickness direction of the base 61. The first end of the conductive layer 62 extends beyond the The base 61, the second end of the conductive layer 62 exceeds the insulating layer 63, and the surface of the portion of the conductive layer 62 that is beyond the base 61 away from the insulating layer 63 is formed as a first binding region 621, and the portion of the conductive layer 62 that exceeds the insulating layer 63 The surface facing away from the substrate 61 is formed as the second binding region 622 .

It should be understood that the substrate 61 , the insulating layer 62 and the conductive layer 63 in the present invention are all flexible and bendable, so that the flexible circuit board 60 can be bent as a whole, and the substrate 61 and the insulating layer 63 are in insulated contact with the conductive layer 62 . The present invention does not limit the material of the conductive layer 60 as long as it can conduct electricity and make the conductive layer 60 bendable. In order to make the conductive layer 60 have good conductivity and bendability, the material of the conductive layer 60 may include copper.

Further, as shown in FIG. 4 , the COF also includes a driver chip 10 fixed on the conductive layer 62, the conductive layer 62 includes two conductive parts 62a arranged at intervals, the first bonding area 621 and the second bonding area The fixed area 622 is respectively formed on the two conductive parts 622, the input end and the output end of the driver chip 10 are respectively connected with the two conductive parts 622, the driver chip 10 and the insulating layer 63 are located on the same side of the conductive layer 62, and the insulating layer 63 An opening corresponding to the driving chip 10 is provided, and the driving chip 10 is disposed in the opening. Therefore, when the flexible circuit board 60 is respectively bound to the printed circuit board 40 and the display substrate 30, as shown in FIG. As for the device, when the flexible circuit board 60 is placed on the side of the display substrate 30 away from the light emitting direction, as shown in FIG. 6 , the driver chip 10 is located inside the bent flexible circuit board 60 to prevent the driver chip 10 from being squeezed.

Further, the end surface of the first end of the conductive layer 62 is flush with the end surface of the insulating layer 63 , and the end surface of the second end of the conductive layer 62 is flush with the end surface of the base 61 .

When the flexible circuit board 60 is bound to the printed circuit board 40 and the display substrate 30 respectively, it can be bound by hot pressing process, so that when the flexible circuit board 60 is hot pressed from both sides of the flexible circuit board 60 Plates 60 are capable of withstanding higher temperatures and pressures. Preferably, the material forming the insulating layer 63 and the material forming the base 61 are independently selected from polyphenylene sulfide, polyphenylene ester, polybenzimidazole, polyphenylene diphenylene, and polyphenylene sulfide. Any of the base siloxanes.

Further, the insulating layer 63 is made of the same material as the substrate 61 , so as to facilitate the fabrication of the flexible circuit board 60 .

As another aspect of the present invention, a display device is provided. As shown in FIG. 7 , the display device includes a display substrate 30, a printed circuit board 40 and the above-mentioned chip-on-film, and the display substrate 30 includes a display area and is located on the display. The lead area around the area, the first binding area 621 of the flexible circuit board 60 is bound to the lead area of the display substrate 30, the second binding area 621 of the flexible circuit board 60 is bound to the printed circuit board 40, and the printed circuit board 40 It is fixedly arranged on the side of the display substrate 30 away from the light emitting direction.

It can be seen that after the flexible circuit board 60 is bent, the second binding area 621 faces the backlight surface of the display substrate, so that the printed circuit board 40 is located inside the flexible circuit board 60 , reducing the overall thickness of the display device. Moreover, since the components 41 of the printed circuit board 40 and the binding area of the printed circuit board 40 are located on the same surface of the printed circuit board 40, the same binding can be used regardless of whether it is a liquid crystal display device or an organic light-emitting display device. The device binds the printed circuit board 40 and the flexible wiring board 60 .

Specifically, as shown in FIG. 7, the display substrate 30 is an organic light-emitting display substrate, which includes a base substrate 31 and a plurality of bottom-emission organic light-emitting diodes 32 disposed on the base substrate 31. The display device also includes a The display substrate 30 is disposed opposite to the encapsulation layer 50 , and an adhesive 80 may also be provided between the encapsulation layer 50 and the display substrate 30 . For the bottom emission type organic display device, the encapsulation layer 50 and the printed circuit board 40 are all located inside the bent flexible circuit board 60, therefore, the overall thickness of the encapsulation layer 50, the display substrate 30, the printed circuit board 40 and the chip-on-chip is Determined by the bending degree of the COF and the thickness of the base substrate 31 , the encapsulation layer 40 does not take up any extra thickness, so that the overall display device is thinner.

In order to reduce the static electricity generated on the encapsulation layer 50 , preferably, the encapsulation layer 50 is conductive, and the printed circuit board 40 is provided with a low-level input terminal, and the low-level input terminal is electrically connected to the encapsulation layer 50 . Therefore, when static electricity is generated on the encapsulation layer 50, the low-level input terminal can conduct away the static electricity, thereby improving the antistatic capability of the display device. Wherein, the encapsulation layer 50 may be a metal cover plate.

Specifically, as shown in FIG. 7 , a conductive glue 70 is disposed between the printed circuit board 40 and the encapsulation layer 50 to electrically connect the low-level input terminal on the printed circuit board 40 to the encapsulation layer 50 .

It can be understood that, the above embodiments are only exemplary embodiments adopted for illustrating the principle of the present invention, but the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims (10)

1. A chip-on-film, comprising a flexible circuit board, said flexible circuit board comprising a conductive layer, said conductive layer comprising a first binding region positioned at the first end of the conductive layer and a second bonding region positioned at the second end of the conductive layer Binding area, the first binding area is used for binding the display substrate, and the second binding area is used for binding the printed circuit board, characterized in that the first binding area and the second binding area The fixed regions are respectively located on two opposite surfaces of the conductive layer. 2. The chip-on-chip according to claim 1, wherein the flexible circuit board further comprises a substrate and an insulating layer, and the substrate, the conductive layer and the insulating layer are sequentially arranged along the thickness direction of the substrate stacked, the first end of the conductive layer is beyond the base, the second end of the conductive layer is beyond the insulating layer, and the surface of the part of the conductive layer that is beyond the base and away from the insulating layer is formed For the first binding region, the surface of the portion of the conductive layer that is beyond the insulating layer and away from the substrate is formed as the second binding region. 3. The chip-on-film according to claim 2, characterized in that, the chip-on-film also includes a driver chip fixed on the conductive layer, the conductive layer includes two conductive parts arranged at intervals, the The first binding area and the second binding area are respectively formed on the two conductive parts, the input end and the output end of the driving chip are respectively connected to the two conductive parts, and the driving chip and the two conductive parts are respectively connected. The insulating layer is located on the same side of the conductive layer, and an opening corresponding to the driving chip is arranged on the insulating layer, and the driving chip is arranged in the opening. 4. The chip-on-chip according to claim 2, wherein the end face of the first end of the conductive layer is flush with the end face of the insulating layer, and the end face of the second end of the conductive layer is flush with the end face of the insulating layer. end face of the base. 5. The chip-on-chip according to claim 2, wherein the material forming the insulating layer and the material forming the base are each independently selected from polyphenylene sulfide, polyphenylene ester, polybenzimidazole, Any one of polyphenylene diphenylsiloxanes. 6 . The chip on film according to claim 2 , wherein the insulating layer is formed of the same material as the substrate. 7. A display device, characterized in that it comprises a display substrate, a printed circuit board, and the chip-on-chip film according to any one of claims 1 to 6, the display substrate comprising a display area and a display area around the display area The lead area, the first binding area of the flexible circuit board is bound to the lead area of the display substrate, the second binding area of the flexible circuit board is bound to the printed circuit board, and the printed circuit board It is fixedly arranged on the side of the display substrate away from the light emitting direction. 8. The display device according to claim 7, wherein the display substrate comprises a base substrate and a plurality of bottom-emission organic light emitting diodes arranged on the base substrate, and the display device further comprises a The encapsulation layer opposite to the display substrate. 9. The display device according to claim 8, wherein the encapsulation layer can conduct electricity, the printed circuit board is provided with a low-level input terminal, and the low-level input terminal is electrically connected to the encapsulation layer. connect. 10. The display device according to claim 9, wherein a conductive glue is provided between the printed circuit board and the encapsulation layer, so as to connect the low-level input terminal on the printed circuit board to the encapsulation layer. electrical connection.