KR102047226B1

KR102047226B1 - Cover window for display device

Info

Publication number: KR102047226B1
Application number: KR1020130008572A
Authority: KR
Inventors: 박혜란; 최원진
Original assignee: 엘지디스플레이 주식회사
Priority date: 2013-01-25
Filing date: 2013-01-25
Publication date: 2019-11-21
Also published as: KR20140095773A

Abstract

The present invention is a base film; A high hardness layer formed on the base film and made of any one of a hexagonal siloxane resin or a urethane resin; A cover window formed under the base film and including an elastic layer including any one of a hexagonal siloxane resin or a urethane resin and any one of polyethylene glycol diacrylate and ethoxylated bisphenol diacrylate. To provide.

Description

Cover window for display device

The present invention relates to a cover window for a display device, and more particularly to a cover window for a display device having excellent hardness and impact resistance characteristics.

In recent years, as the society enters the information age, the display field for processing and displaying a large amount of information has been rapidly developed. In recent years, as a flat panel display device having excellent performance of thinning, light weight, and low power consumption, Flat panel displays, such as liquid crystal displays, are replacing conventional cathode ray tubes (CRTs).

In particular, recently, a touch type display device in which a user operates by touching a panel has been in the spotlight.

For example, a touch type display device may be classified into a resistive film type, a capacitive type, and the like. A common feature of all touch type display devices is that a user directly touches the outermost surface of the display device. Accordingly, the cover window constituting the outermost surface layer of the touch type display device is required to have high hardness.

The conventional cover window has a structure in which a hard coating layer made of acrylate is laminated on a base film made of polyethylene terephthalate (PET). That is, since PET has a soft characteristic, by forming a hard coating layer having a high hardness on top of it, the hardness characteristic is improved.

However, such cover windows are not good in impact resistance characteristics, so the problem that cracks occur in the cover windows due to external impacts frequently occurs.

The present invention is intended to solve the problem of lowering the impact resistance of the cover window used in the display device.

In order to solve the above problems, the base film; A high hardness layer formed on the base film and made of any one of a hexagonal siloxane resin or a urethane resin; A cover window formed under the base film and including an elastic layer including any one of a hexagonal siloxane resin or a urethane resin and any one of polyethylene glycol diacrylate and ethoxylated bisphenol diacrylate. To provide.

In the cover window for a display device of the present invention, any one of the hexagonal siloxane resin or the urethane resin has a weight ratio (wt%) of 10 to 30, and the polyethylene glycol diacrylate or the ethoxylated bisphenol di Any one of the acrylates is characterized by having a weight ratio of 70 ~ 90.

In the cover window for a display device of the present invention, the high hardness layer has a first thickness, and the elastic layer has a second thickness larger than the first thickness.

In the cover window for a display device of the present invention, the first thickness is 70 to 80 µm, and the second thickness is 90 to 100 µm.

In the cover window for a display device of the present invention, the hexagonal siloxane resin is represented by the following formula, and R ¹ is an epoxy acrylate.

In the cover window for a display device of the present invention, the urethane acrylate resin is represented by the following formula, R is characterized in that the urethane.

In the cover window for a display device of the present invention, the polyethylene glycol diacrylate is represented by the following formula, and n is a positive integer.

In the cover window for a display device of the present invention, the ethoxylated bisphenol diacrylate is represented by the following formula, and n is a positive integer.

In the cover window for a display device of the present invention, the base film is made of any one of polyethylene terephthalate (PET), polycarbonate (PC), and polymethylmetacrylate (PMMA), a bilayer structure of PC / PMMA, or PMMA / PC / PMMA. It is characterized in that the triple layer structure.

The cover window of the present invention is formed on top of the base film and has a high hardness layer having excellent hardness characteristics and an elastic layer formed under the base film and having excellent elasticity, thereby having excellent hardness characteristics and impact resistance characteristics.

Therefore, it is possible to prevent both scratch generation due to external contact and crack generation due to external impact.

1 is a schematic exploded perspective view of a display device including a cover window according to an exemplary embodiment of the present invention.
2 is a cross-sectional view of a cover window for a display device according to an exemplary embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

1 is a schematic exploded perspective view of a display device including a cover window according to an exemplary embodiment of the present invention.

As shown in FIG. 1, the display device includes a display device 100, a back cover 200 for accommodating the display device 100 under the display device 100, and a display device 100 of the display device 100. And a cover window 300 covering the front surface.

The display device 100 may be a liquid crystal display device, an organic light emitting display device, or the like.

For example, when the display device 100 is a liquid crystal display device, the display device 100 may include a display panel 110, a main frame 140 covering side surfaces of the display panel 110, and the display. The bottom frame 150 may cover the rear surface of the panel 110 and may be coupled to the main frame 140.

In this case, although not shown, the display panel 110 may include a first substrate on which a thin film transistor, a pixel electrode, a common electrode, and the like are formed, a second substrate facing the first substrate, and a color filter and the like; The liquid crystal layer may be interposed between the first substrate and the second substrate.

In addition, a backlight unit that provides light to the “display panel 110” is positioned between the display panel 110 and the “bottom” frame 150.

The cover window 300 covers the entire surface of the display device 100 and is exposed to the outside, thereby making a user's touch and applying an external impact.

At this time, the cover window 300 of the present invention is formed on the upper surface of the base film of the hexagonal siloxane resin or urethane acrylate resin to have a high hardness characteristics, the hexagonal agent to have excellent elasticity on the lower surface of the base film The lower layer which consists of either siloxane resin or urethane acrylate resin, and any of polyethyleneglycol diacrylate or ethoxylated bisphenol diacrylate is formed, and has the outstanding hardness characteristic and impact resistance.

That is, referring to FIG. 2, which is a cross-sectional view of a cover window for a display device according to an exemplary embodiment of the present invention, the cover window 300 includes a base film 310 and a high hardness layer stacked on the base film 310. 320 and an elastic layer 330 stacked below the base film 310.

The base film 310 may have a single layer structure of any one of polyethylene terephthalate (PET), polycarbonate (PC), and polymethylmetacrylate (PMMA), a double layer structure of PC / PMMA, or a triple layer structure of PMMA / PC / PMMA. .

In addition, the high hardness layer 320 may be made of a hexahedral siloxane resin represented by the following formula (1) or a urethane acrylate resin represented by the following formula (2).

Formula 1

In Formula 1, R ¹ may be an epoxy acrylate.

Formula 2

In Formula 2, R may be urethane.

The elastic layer 330 may be represented by any one of a hexagonal siloxane resin represented by Chemical Formula 1 or a urethane acrylate resin represented by Chemical Formula 2 and a polyethylene glycol diacrylate represented by Chemical Formula 3, or Chemical Formula 4 It consists of any one of the ethoxylated (ethoxylated) bisphenol diacrylate.

Formula 3

Formula 4

In Formulas 3 and 4, n is a positive integer.

In FIG. 2, the high hardness layer 320 is made of a hexagonal siloxane resin, and the elastic layer 330 is made of polyethylene glycol diacrylate in a state bonded to the hexagonal siloxane resin.

As described above, a high hardness layer 320 made of a hexagonal siloxane resin or a urethane acrylate resin is formed on the upper portion thereof, and either one of the hexagonal siloxane resin or the urethane acrylate resin is formed on the lower portion thereof and polyethylene glycol diacrylate resin. The cover window 300 including the base film 310 on which the elastic layer 330 including any one of ethoxylated bisphenol diacrylate is formed is contacted by the high hardness layer 320. It is possible to prevent the occurrence of scratches and the like, the external impact is absorbed by the elastic layer 330 to prevent the crack generated in the high hardness layer (320).

On the other hand, the high hardness layer 320 changes the hardness characteristics according to the thickness. The hardness characteristics, impact resistance and crack resistance of the high hardness layer 320 made of a hexagonal siloxane resin were measured according to the thicknesses, and are shown in Table 1 below. Hardness characteristics were tested by a pencil test, impact resistance was measured using a steel ball of 28g, crack resistance was measured by a bending test.

Thickness [㎛] Hardness Impact resistance Crack resistance 15 2H 10 cm breakage 2Φ OK 30 2 ~ 3H 15 cm breakage 3Φ OK 45 3 ~ 4H 18cm breakage 3Φ OK 60 5H 25 cm broken 3Φ OK 75 8 ~ 9H 30 cm breakage 4Φ OK 90 9H 30 cm breakage 5Φ OK 100 9H 30 cm breakage 5Φ OK

As can be seen in Table 1, the high hardness layer 320 has a high hardness and impact resistance at a thickness of 75㎛ or more and has excellent crack resistance at a thickness of 75㎛ or less. Therefore, the thickness of the high hardness layer 320 is preferably 70 ~ 80㎛.

On the other hand, the elastic layer 330 should have a certain level of hardness and high impact resistance. To this end, while varying the composition ratio of the material constituting the elastic layer 330, the hardness characteristics, impact resistance and crack resistance were measured and shown in Table 2. A is a hexagonal siloxane resin of Formula 1, and B is a polyethylene glycol diacrylate of Formula 3. Hardness characteristics, impact resistance and crack resistance were measured in the same manner as in Table 1.

Composition ratio (wt%) Hardness Impact resistance Crack resistance A B 100 0 9H 30 cm breakage 4Φ OK 80 20 5H 40 cm broken 3 ~ 4Φ OK 60 40 4H 70 cm breakage 3Φ OK 40 60 2H 80cm striker 2 ~ 3Φ OK 20 80 HB-H 100 cm OK 1Φ OK 0 100 4B or less 100 cm OK 1Φ OK

As can be seen in Table 2, when the elastic layer 330 contains 20wt% of hexagonal siloxane resin and 80wt% of polyethylene glycol diacrylate, it has relatively low strength but high impact resistance and crack resistance by elasticity. You will have a last name. Therefore, the elastic layer 330 is any one of about 10 to 30wt% of hexagonal siloxane resin or urethane acrylate resin and any one of 70 to 90wt% of polyethylene glycol diacrylate or ethoxylated bisphenol diacrylate. It is preferable to comprise a.

Meanwhile, the cover window 300 is affected by the thicknesses of the high hardness layer 320 and the elastic layer 330 formed on the base film 310. When the thickness of the high hardness layer 320 is about 75 μm through the experiments of Table 1, the elastic layer 330 composed of 20 wt% hexagonal siloxane resin and 80 wt% polyethylene glycol diacrylate is exhibited. Hardness, impact resistance, crack resistance, and warpage characteristics were measured while changing the thickness of) and are shown in Table 3. The bending characteristics of the cover window are required to be within ± 3 mm.

Hard Hardness Layer Lower layer [㎛] Hardness Impact resistance Crack resistance Flexural characteristics 75 25 3 ~ 4H 50 cm breakage 3Φ OK -10.0mm 75 50 4H 65 cm stroke 2 ~ 3Φ OK -3.5mm 75 75 5 ~ 6H 70 cm stroke 2Φ OK -0.8mm 75 100 7 ~ 8H 85 cm stroke 2Φ OK -0.3mm

As shown in Table 3, as the thickness increases, the hardness properties, impact resistance, crack resistance and warpage characteristics are improved. However, when the elastic layer is composed of 20 wt% hexagonal siloxane resin and 80 wt% polyethylene glycol diacrylate, since the viscosity is low, it is preferable to form the elastic layer 330 having a thickness uniformity of 100 μm by the coating process. Very difficult.

Therefore, the thickness of the elastic layer 330 is preferably about 90 ~ 100㎛, considering the thickness of the cover window 300 and the characteristics of the high hardness layer 320 and the elastic layer 330, the high hardness layer ( The first thickness (t1 of FIG. 2) of 320 is preferably smaller than the second thickness (t2 of FIG. 2) of the elastic layer 330.

The cover window for a display device of the present invention is formed on a base film, a high hardness layer formed on the base film and made of a hexagonal siloxane resin or a urethane acrylate resin, and formed on a lower part of the base film and formed on a hexagonal siloxane resin or a urethane acrylate resin. By including the elastic layer which consists of either and polyethyleneglycol diacrylate or any of ethoxylated bisphenol diacrylate, it has the outstanding hardness characteristic and impact resistance. Therefore, damage to the cover window due to external contact and external impact can be prevented.

In addition, in consideration of the characteristics and the thickness of the cover window, the high hardness layer preferably has a thickness of about 70 ~ 80㎛, the elastic layer preferably has a thickness of about 90 ~ 100㎛.

In addition, the elastic layer comprises any one of about 10 to 30wt% of hexagonal siloxane resin or urethane resin, and 70 to 90wt% of polyethylene glycol diacrylate or ethoxylated bisphenol diacrylate. , Has excellent elasticity.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art various modifications and changes to the present invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

300: cover window 310: base film
320: high hardness layer 330: elastic layer

Claims

A base film;
A high hardness layer formed on an upper surface of the base film and made of a first material which is a hexagonal siloxane resin;
A cover window formed on an underside of the base film and comprising an elastic layer comprising the first material and a second material of any one of polyethylene glycol diacrylate and ethoxylated bisphenol diacrylate.

The method of claim 1,
In the elastic layer, the first material has a weight ratio (wt%) of 10 to 30, the second material has a weight ratio of 70 to 90, the cover window for a display device.

The method of claim 2,
The high hardness layer has a first thickness, and the elastic layer has a second thickness greater than the first thickness cover window for a display device.

The method of claim 3, wherein
The first thickness is 70 ~ 80㎛, the second thickness is 90 ~ 100㎛ Cover window for a display device.

The method of claim 1,
The hexagonal-sided siloxane resin is to be represented by the formula, R ¹ is the cover window for a display device, characterized in that an epoxy acrylate.

delete

The method of claim 1,
The polyethylene glycol diacrylate is represented by the following formula, wherein n is a positive integer cover window for a display device.

The method of claim 1,
The ethoxylated bisphenol diacrylate is represented by the following formula, and n is a positive integer cover window for a display device.

The method of claim 1,
The base film is a cover window for a display device, characterized in that the single layer structure consisting of any one of polyethylene terephthalate (PET), polycarbonate (PC), polymethylmethacrylate (PMMA).

A display element;
A back cover positioned under the display element and accommodating the display element;
The cover window of any one of claims 1 to 5 and 7 to 9 covering the entire surface of the display device.
Display device comprising a.