Display apparatus
A display apparatus includes a display panel. A cover window covers the display panel. A first film is arranged over the cover window. The first film has a first rate of change of a storage modulus at frequencies due to external impacts that are below a reference frequency and a second rate of change of the storage modulus at frequencies due to external impacts that are above the reference frequency.
1. A display apparatus comprising:
a display panel;
a cover window covering the display panel; and
a first film arranged over the cover window, the first film having a first rate of change of a storage modulus at frequencies due to external impacts that are below a reference frequency and a second rate of change of the storage modulus at frequencies due to external impacts that are above the reference frequency, wherein the first rate of change is different from the second rate of change.
2. The display apparatus of claim 1 , wherein the reference frequency is about 1 Hz.
3. The display apparatus of claim 1 , wherein the first rate of change is less than the second rate of change.
4. The display apparatus of claim 1 , wherein a tensile modulus of the first film is in a range of about 4 GPa to about 11 GPa at 25° C.
5. The display apparatus of claim 1 , wherein the first film is arranged on a first side of the cover window, and the display panel is arranged on a second side of the cover window that is opposite to the first side of the cover window.
6. The display apparatus of claim 1 , wherein a light transmittance of the first film is at least about 90%.
7. The display apparatus of claim 1 , wherein:
the display panel includes a first folding axis and a second folding axis arranged in a first direction, the first folding axis extends parallel to the second folding axis; and
the display panel is configured to be in-folded around the first folding axis and the second folding axis.
8. The display apparatus of claim 1 , further comprising a second film arranged between the display panel and the cover window, the second film is configured to absorb impacts.
9. The display apparatus of claim 8 , wherein at least one of the first film and the second film is coated on the cover window.
10. The display apparatus of claim 8 , wherein the second film includes an elastomer.
11. The display apparatus of claim 8 , wherein a thickness of the second film is in a range of about 50 μm to about 75 μm.
12. The display apparatus of claim 8 , wherein an elastic modulus of the second film at 85° C. is in a range of about 100 MPa to about 600 MPa.
13. The display apparatus of claim 8 , wherein an elastic modulus of the second film at 25° C. is in a range of about 600 MPa to about 1000 MPa.
14. The display apparatus of claim 8 , wherein an elastic modulus of the second film at −20° C. is in a range of about 1000 MPa to about 1500 MPa.
15. The display apparatus of claim 8 , wherein:
the second film includes a plurality of layers; and
an elastic modulus of a first layer that is immediately adjacent to the cover window has a largest elastic modulus among the plurality of layers.
16. The display apparatus of claim 15 , wherein:
the second film includes a first layer adjacent to the cover window and a second layer adjacent to the display panel; and
a thickness of the first layer is less than a thickness of the second layer.
17. The display apparatus of claim 8 , wherein:
the display panel includes a first folding axis and a second folding axis arranged in a first direction, the first folding axis extends parallel to the second folding axis; and
the display panel is configured to be in-folded around the first folding axis and the second folding axis.
18. A display apparatus comprising:
a display panel;
a cover window covering the display panel; and
a second film arranged between the display panel and the cover window, the second film is configured to absorb impacts, wherein the second film includes a plurality of lavers and an elastic modulus of a first layer that is immediately adjacent to the cover window has a largest elastic modulus among the plurality of layers,
wherein the display panel, the cover window, and the second film are configured to be in-folded around a first folding axis and a second folding axis arranged in a first direction, the first folding axis extends parallel to the second folding axis.
19. The display apparatus of claim 18 , wherein an elastic modulus of the second film at 85° C. is in a range of about 100 MPa to about 600 MPa.
20. The display apparatus of claim 18 , wherein an elastic modulus of the second film at 25° C. is in a range of about 600 MPa to about 1000 MPa.
21. The display apparatus of claim 18 , wherein an elastic modulus of the second film at −20° C. is in a range of about 1000 MPa to about 1500 MPa.
22. The display apparatus of claim 18 , wherein:
the plurality of layers includes a second layer; and
a thickness of the first layer is less than a thickness of the second layer.