# US 12,604,426 B2 · Cover plate and display device

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- Number: US 12,604,426 B2
- Document ID: US12604426B2
- Status: Granted
- Kind: B2
- Application number: 17/908,644
- Filed: 2021-11-03
- Published: 2024-06-13
- Granted: 2026-04-14
- Earliest claimed: 2021-03-05
- Assignees: Chengdu Boe Optoelectronics Technology Co., Ltd.; Boe Technology Group Co., Ltd.
- Applicants: Chengdu BOE Optoelectronics Technology Co., Ltd.; BOE Technology Group Co., Ltd.
- Inventors: Shaokui Liu; Zhihui Wang; Danping Shen; Wei Zeng; Qiang Tang
- Web page: https://patentgrep.com/patent/US12604426B2

## CPC

- H05K 5/03: Covers
- B32B 7/022: Mechanical properties
- B32B 7/12: using interposed adhesives or interposed materials with bonding properties
- B32B 27/08: of synthetic resin
- B32B 27/281: {comprising polyimides}
- B32B 27/36: comprising polyesters
- B32B 27/40: comprising polyurethanes
- B32B 2255/10: on synthetic resin layer or on natural or synthetic rubber layer
- B32B 2255/26: Polymeric coating
- B32B 2274/00: Thermoplastic elastomer material
- B32B 2307/51: Elastic
- B32B 2307/54: Yield strength; Tensile strength
- B32B 2307/584: Scratch resistance
- B32B 2307/7376: Thickness
- B32B 2457/20: Displays, e.g. liquid crystal displays, plasma displays
- Y02E 10/549: Organic PV cells
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Provided is a cover plate. The cover plate includes a substrate, a first buffer layer and a second buffer layer. The substrate includes a first surface and a second surface, and the first surface faces a flexible display panel. The first buffer layer is laminated on the first surface, and an elastic modulus of the first buffer layer ranges from 10 MPa to 2 GPa. The second buffer layer is laminated on the second surface, and an elastic modulus of the second buffer layer ranges from 60 MPa to 7 GPa.

## Claims

### Claim 1

A cover plate, wherein the cover plate is applicable to a flexible display panel, the cover plate comprising:
a substrate comprising a first surface and a second surface opposite to each other, the first surface facing the flexible display panel;
a first buffer layer laminated on the first surface; and
a second buffer layer laminated on the second surface
wherein the cover plate further comprises:
a first elastic layer laminated on a side of the second buffer layer away from the substrate;
a first support layer laminated on a side of the first elastic layer away from the substrate;
a protective layer laminated on the side of the second buffer layer away from the substrate, wherein the protective layer is an outermost layer among all layers on the side of the second buffer layer away from the substrate; and
a first adhesive layer adhered between the protective layer and a layer adjacent to the protective layer,
wherein the protective layer comprises:
a second support layer laminated on a side of the first adhesive layer away from the substrate; and
a scratch-resistant layer laminated on a side of the second support layer away from the substrate,
wherein when temperature ranges from 15° C. to 35° C., a viscosity of the first adhesive layer is greater than 700 gf/inch, a creep coefficient of first adhesive layer is greater than 300%, and a restitution coefficient of the first adhesive layer is greater than 80%; and
when the temperature is less than −50° C., the viscosity of the first adhesive layer is less than 30 gf/inch, wherein the first adhesive layer is a pressure-sensitive adhesive layer.

### Claim 2 (depends on 1)

The cover plate according to claim 1, wherein
the first buffer layer is any one of a flexible polyurethane (PU) layer, a polyimide (PI) layer, and a polymethyl methacrylate (PMMA) layer, or the first buffer layer is formed by laminating at least two of the flexible PU layer, the PI layer and the PMMA layer; and
the second buffer layer is any one of the flexible PU layer, the PI layer and the PMMA layer, or the second buffer layer is formed by laminating at least two of the flexible PU layer, the PI layer and the PMMA layer.

### Claim 3 (depends on 1)

The cover plate according to claim 1, wherein in a direction perpendicular to the first surface, a thickness of the first buffer layer ranges from 5 μm to 40 μm, and a thickness of the second buffer layer ranges from 5 μm to 40 μm.

### Claim 4 (depends on 1)

The cover plate according to claim 1, wherein the first elastic layer is a thermoplastic polyurethane (TPU) layer.

### Claim 5 (depends on 1)

The cover plate according to claim 1, wherein the first support layer is a polyethylene terephthalate (PET) layer.

### Claim 6

A display device, comprising a cover plate and a flexible display panel laminated in sequence, wherein the cover plate is applicable to the flexible display panel, and comprises:
a substrate comprising a first surface and a second surface opposite to each other, the first surface facing the flexible display panel;
a first buffer layer laminated on the first surface; and
a second buffer layer laminated on the second surface,
wherein the cover plate further comprises:
a first elastic layer laminated on a side of the second buffer layer away from the substrate,
wherein the cover plate further comprises:
a first elastic layer laminated on a side of the second buffer layer away from the substrate;
a first support layer laminated on a side of the first elastic layer away from the substrate;
a protective layer laminated on the side of the second buffer layer away from the substrate, wherein the protective layer is an outermost layer among all layers on the side of the second buffer layer away from the substrate; and
a first adhesive layer adhered between the protective layer and a layer adjacent to the protective layer,
wherein the protective layer comprises:
a second support layer laminated on a side of the first adhesive layer away from the substrate; and
a scratch-resistant layer laminated on a side of the second support layer away from the substrate,
wherein when temperature ranges from 15° C. to 35° C., a viscosity of the first adhesive layer is greater than 700 gf/inch, a creep coefficient of first adhesive layer is greater than 300%, and a restitution coefficient of the first adhesive layer is greater than 80%; and
when the temperature is less than −50° C., the viscosity of the first adhesive layer is less than 30 gf/inch, wherein the first adhesive layer is a pressure-sensitive adhesive layer.

### Claim 7 (depends on 6)

The display device according to claim 6, further comprising:
a second elastic layer laminated on a side of the flexible display panel away from the cover plate, wherein a tensile strength of the second elastic layer ranges from 5 MPa to 10 MPa.

### Claim 8 (depends on 7)

The display device according to claim 7, wherein
the second elastic layer is any one of a thermoplastic polyurethane (TPU) elastomer rubber layer, a foam layer, a polyethylene terephthalate (PET) layer, a polyimide (PI) layer, and an optically clear adhesive (OCA) layer; or
the second elastic layer is formed by laminating at least two of the (TPU) elastomer rubber layer, the foam layer, the (PET) layer, the PI layer, and the OCA layer.

### Claim 9 (depends on 6)

The display device according to claim 6, wherein along a first direction, a length of the cover plate is greater than a length of the flexible display panel, the first direction being perpendicular to an extension direction of a bending line when the display device is bent, and the first direction being parallel to the first surface.

### Claim 10 (depends on 6)

The display device according to claim 6, wherein
the first buffer layer is any one of a flexible polyurethane (PU) layer, a polyimide (PI) layer, and a polymethyl methacrylate (PMMA) layer, or the first buffer layer is formed by laminating at least two of the flexible PU layer, the PI layer and the PMMA layer; and
the second buffer layer is any one of the flexible PU layer, the PI layer and the PMMA layer, or the second buffer layer is formed by laminating at least two of the flexible PU layer, the PI layer and the PMMA layer.

### Claim 11 (depends on 6)

The display device according to claim 6, wherein in a direction perpendicular to the first surface, a thickness of the first buffer layer ranges from 5 μm to 40 μm, and a thickness of the second buffer layer ranges from 5 μm to 40 μm.

### Claim 12 (depends on 6)

The display device according to claim 6, wherein the first elastic layer is a thermoplastic polyurethane (TPU) layer.

### Claim 13 (depends on 6)

The display device according to claim 6, wherein the first support layer is a polyethylene terephthalate (PET) layer.