Flexible cover window with improved strength
Disclosed is a glass-based flexible cover window with improved strength including a planar portion formed so as to correspond to a planar region of a flexible display and a folding portion formed so as to be connected to the planar portion, the folding portion being formed so as to correspond to a folding region of the flexible display, wherein the flexible cover window includes a glass substrate, an adhesive buffer layer formed on the glass substrate, a protective film layer formed on the adhesive buffer layer, and a hard coating layer formed on the protective film layer. The protective film layer is formed on the glass substrate, whereby strength and folding characteristics of the flexible cover window are improved, and inherent texture of glass is maintained while the overall thickness of the flexible cover window is reduced, and therefore aesthetics of the flexible cover window are improved.
1 . A glass-based flexible cover window with improved strength comprising a planar portion formed so as to correspond to a planar region of a flexible display and a folding portion formed so as to be connected to the planar portion, the folding portion being formed so as to correspond to a folding region of the flexible display, wherein the flexible cover window comprises:
a glass substrate;
an adhesive buffer layer formed on a front surface of the glass substrate, wherein the adhesive buffer layer is made of an optically clear resin (OCR) having a strength (storage modulus) greater than 0.01 GPa and less than or equal to 1 GPa, wherein the optically clear resin is selected from the group consisting of acrylic, epoxy, urethane, urethane acrylic composite, and a urethane composite;
a protective film layer formed on the adhesive buffer layer, wherein the protective film layer has a higher rigidity than the adhesive buffer layer, and a strength of the protective film layer is different from a strength of the adhesive buffer layer, and the protective film layer is made of any one of polypropylene (PP) and polyethylene naphthalate (PEN); and
a hard coating layer formed on the protective film layer,
wherein the protective film layer on which the hard coating layer is formed is laminated using the adhesive buffer layer on the front surface of the glass substrate, so that the hard coating layer, the protective film layer and the glass substrate form a lamination structure, and the adhesive buffer layer is a UV-hardened layer, and
wherein a thickness of the adhesive buffer layer is greater than a thickness of the hard coating layer, and the thickness of the hard coating layer is smaller than a thickness of the protective film layer.
2 . The flexible cover window according to claim 1 , wherein the protective film layer has a thickness of 5 to 100 μm.
3 . The flexible cover window according to claim 1 , wherein the adhesive buffer layer has a thickness of 1 to 75 μm.
4 . The flexible cover window according to claim 1 , further comprising a functional layer formed on the hard coating layer.
5 . The flexible cover window according to claim 1 , wherein the adhesive buffer layer is made of a material configured such that the adhesive buffer layer has an equal strength or different strengths at the planar portion and the folding portion.
6 . The flexible cover window according to claim 1 , wherein the glass substrate is integrally formed.
7 . The flexible cover window according to claim 6 , wherein the glass substrate is formed such that the folding portion is slimmer than the planar portion.
8 . The flexible cover window according to claim 1 , further comprising an adhesive layer formed on a back surface of the glass substrate and configured to be adhered to a flexible display panel of the flexible display.
9 . The flexible cover window according to claim 8 , wherein the adhesive layer is formed so as to have an optically clear adhesive (OCA) structure or an OCA/support film layer/OCA structure.
10 . The flexible cover window according to claim 9 , wherein the support film layer is made of at least one of polyethylene terephthalate (PET), polypropylene (PP), polyethylene naphthalate (PEN), and polycarbonate (PC).