Back Plate Film
The present application relates to a back plate film. The present application provides a back plate film for an under-display camera in which a front camera of a mobile phone can capture a subject without image distortion. The back plate film of the present application can be usefully used in, for example, an OLED panel.
1 . A back plate film comprising:
a retardation base material layer; and
a first pressure-sensitive adhesive layer formed on one side of the retardation base material layer, wherein
an absolute value of an in-plane retardation (R0) value calculated by Equation 1 below of the retardation base material layer is 100 nm or less, and an absolute value of a thickness direction retardation (Rth) value calculated by Equation 2 below is 100 nm or less:
R
0
=
(
nx
-
ny
)
×
d
[
Equation
1
]
Rth
=
[
(
nx
+
ny
)
/
2
-
nz
]
×
d
[
Equation
2
]
wherein, nx, ny, and nz are the refractive indices of the retardation base material layer in the x-axis direction, y-axis direction, and z-axis direction for light with a wavelength of 550 nm, respectively, and d is the thickness (nm) of the retardation base material layer.
2 . The back plate film according to claim 1 , wherein the absolute value of the in-plane retardation (R0) value of the retardation base material layer is 0.1 nm or more.
3 . The back plate film according to claim 1 , wherein the absolute value of the thickness direction retardation (Rth) value of the retardation base material layer is 0.1 nm or more.
4 . The back plate film according to claim 1 , wherein the retardation base material layer has a thickness in a range of 20 μm to 200 μm.
5 . The back plate film according to claim 1 , comprising an antistatic layer formed on a side of the retardation base material layer on which the first pressure-sensitive adhesive layer is not formed, wherein the antistatic layer has a sheet resistance in a range of 10 4 Ω/square to 10 11 Ω/square.
6 . The back plate film according to claim 1 , wherein the first pressure-sensitive adhesive layer comprises an acrylic resin and a curing agent, and has a thickness in a range of 20 μm to 200 μm.
7 . The back plate film according to claim 1 , wherein the first pressure-sensitive adhesive layer has a pressure-sensitive adhesive force to glass at a peel rate of 0.3 mpm in a range of 1000 gf/in to 4000 gf/in.
8 . The back plate film according to claim 1 , further comprising a protective film present on the retardation base material layer side.
9 . The back plate film according to claim 8 , wherein the protective film comprises a first base material film and a second pressure-sensitive adhesive layer formed on one side of the first base material film, the first base material film has a thickness in a range of 20 μm to 200 μm, and the second pressure-sensitive adhesive layer has a thickness in a range of 10 μm to 200 μm.
10 . The back plate film according to claim 9 , wherein the first base material film is a PET (polyethylene terephthalate) film.
11 . The back plate film according to claim 9 , further comprising an antistatic layer formed on one side of at least one of the first base material film and the second pressure-sensitive adhesive layer, wherein the antistatic layer has a sheet resistance of 10 4 Ω/square to 10 11 Ω/square.
12 . The back plate film according to claim 8 , further comprising a release film present on the first pressure-sensitive adhesive layer side.
13 . The back plate film according to claim 12 , wherein the release film comprises a second base material film and a silicone layer formed on one side of the second base material film.
14 . The back plate film according to claim 13 , wherein the second base material film is a PET (polyethylene terephthalate) film.
15 . The back plate film according to claim 13 , comprising an antistatic layer formed on one or both sides of the second base material film, wherein the antistatic layer has a sheet resistance in a range of 10 4 Ω/square to 10 11 Ω/square.
16 . An organic light emitting display comprising the back plate film of claim 1 and an OLED (organic light emitting diode) panel.
17 . The organic light emitting display according to claim 16 , wherein the first pressure-sensitive adhesive layer of the back plate film is in contact with the OLED panel.
18 . A mobile phone sequentially comprising a cover window, a polarizing plate, a touch sensor, an OLED (organic light emitting diode) panel, the back plate film of claim 1 , and a camera.
19 . The mobile phone according to claim 18 , wherein no front camera region is punched on the OLED panel.