Display device including adhesive film with conductive ball
A display device includes a display panel including a first signal pad and a second signal pad, a circuit board overlapped with the first and second signal pads, and an adhesive film overlapped with the first and second signal pads and disposed between the circuit board and the display panel. The adhesive film includes a base resin and a plurality of conductive balls dispersed in the base resin. The circuit board includes a first driving pad and a second driving pad. The first and second driving pads protrude toward the adhesive film and are arranged in a first direction. The first and second driving pads overlap with the first and second signal pads, respectively. The display device may be configured to satisfy the inequality: T ≥ G + B × S W + S .
1. A display device, comprising:
a display panel including a display region and a non-display region and including a first signal pad, an insulating layer and a second signal pad, wherein the first signal pad, the insulating layer, and the second signal pad are arranged in a first direction in the non-display region;
a circuit board disposed on the display panel and overlapped with the first and second signal pads in a thickness direction; and
an adhesive film disposed between the circuit board and the display panel and overlapped with the first and second signal pads,
wherein the adhesive film comprises a base resin and a plurality of conductive balls dispersed in the base resin,
the circuit board comprises a first driving pad and a second driving pad, the first and second driving pads protruding toward the adhesive film and arranged in the first direction,
the first driving pad and the second driving pad overlap with the first signal pad and the second signal pad, respectively,
the adhesive film comprises a first region overlapped with the first driving pad, a second region overlapped with the second driving pad, and a third region defined as a region between the first region and the second region,
a height of a bottom surface of the first region and a height of a bottom surface of the third region in the thickness direction are the same,
the plurality of conductive balls comprises a first conductive ball disposed in the first region, a second conductive ball disposed in the second region, and a third conductive ball disposed in the third region,
a diameter of the third conductive ball in the thickness direction is substantially a same as a thickness of the adhesive film T,
the display device satisfies a following formula 1:
T
≥
G
+
B
×
S
W
+
S
,
[
Formula
1
]
where B is a thickness of the first driving pad in the thickness direction,
T is the thickness of the adhesive film before bonding the circuit board to the display panel,
G is a distance between the first signal pad and the first driving pad,
S is a distance between the first driving pad and the second driving pad, and
W is a width of the first driving pad in the first direction, and
G is greater than B.
2. The display device of claim 1 , wherein the base resin is disposed between the first driving pad and the second driving pad.
3. The display device of claim 1 , wherein
the first to third conductive balls have a same volume.
4. The display device of claim 3 , wherein the display panel is parallel to a plane defined by the first direction and a second direction crossing the first direction,
each of lengths of the first and second conductive balls in a third direction perpendicular to the plane is equal to the distance G, and
the third direction is the thickness direction.
5. The display device of claim 3 , wherein a diameter of the third conductive ball in the thickness direction is greater than the distance G.
6. The display device of claim 3 , wherein the thickness B is smaller than a diameter of the third conductive ball in the thickness direction.
7. The display device of claim 3 , wherein the first conductive ball is in direct contact with both of the first signal pad and the first driving pad, and
the second conductive ball is in direct contact with both of the second signal pad and the second driving pad.
8. The display device of claim 3 , wherein a change in diameter of the plurality of conductive balls is defined as (a diameter of the third conductive ball in the thickness direction−a diameter of the first conductive ball in the thickness direction)/the diameter of the third conductive ball×100 (percentages: %), and
the change in diameter of the plurality of conductive balls is less than or equal to about 25%.
9. The display device of claim 1 , wherein the plurality of conductive balls is arranged in the first direction.
10. The display device of claim 1 , wherein the display panel includes a first pixel and a second pixel, which overlap with the display region, and
each of the first and second signal pads transmits an electrical signal to each of the first and second pixels.
11. The display device of claim 1 , wherein the circuit board is a driving chip.
12. The display device of claim 1 , wherein the circuit board is a flexible circuit board.
13. The display device of claim 1 , wherein the first signal pad and the second signal pad have a same shape, and
the first driving pad and the second driving pad have a same shape.
14. The display device of claim 1 , wherein the base resin comprises a heat-curing resin or a photo-curing resin.
15. The display device of claim 1 , wherein the plurality of conductive balls comprises at least one of metals, metal oxides, or metal nitrides.
16. The display device of claim 1 , wherein the plurality of conductive balls is arranged to form a single layer.
17. A display device, comprising:
a display panel including a display region and a non-display region and including a first signal pad, an insulating layer, and a second signal pad, wherein the first signal pad, the insulating layer, and the second signal pad are arranged in a first direction in the non-display region;
a circuit board disposed on the display panel and overlapped with the first and second signal pads in a thickness direction; and
an adhesive film disposed between the circuit board and the display panel and overlapped with the first and second signal pads,
wherein the adhesive film comprises a base resin and a plurality of conductive balls dispersed in the base resin,
the circuit board comprises a first driving pad and a second driving pad, the first and second driving pads protruding toward the adhesive film and arranged in the first direction,
the first driving pad and the second driving pad overlap with the first signal pad and the second signal pad, respectively,
the adhesive film comprises:
a first region overlapped with the first driving pad;
a second region overlapped with the second driving pad; and
a third region defined between the first region and the second region,
a height of a bottom surface of the first region and a height of a bottom surface of the third region in the thickness direction are the same,
the base resin is disposed between the first driving pad and the second driving pad,
a diameter of the conductive balls disposed in the third region is substantially a same as a thickness of the adhesive film before bonding the circuit board to the display panel, and
a distance between the first signal pad and the first driving pad is greater than a thickness of the first driving pad in the thickness direction.
18. The display device of claim 17 , wherein the plurality of conductive balls is arranged to form a single layer.
19. The display device of claim 17 , wherein each of the plurality of conductive balls disposed in the first region is in direct contact with each of the first signal pad and the first driving pad.