KR20230038802A - Image display device and manufacturing method thereof - Google Patents

Abstract

The organic EL display device 1 of the present invention includes a window member 2, an impact absorbing member 3, an organic EL panel member 4, and a protective member 5 in this order on the rear side. The shock absorbing member 3 has a total light transmittance of 60% or more, a ball impact absorption per unit thickness of 0.27%/μm or more, and a pen impact absorption rate per unit thickness of 0.10%/μm or more.

Description

Image display device and manufacturing method thereof

The present invention relates to an image display device and a manufacturing method thereof.

Conventionally, it is known that an image display device includes an image display member. Such an image display device is required to have high optical reliability.

Further, an image display device including an impact absorbing film capable of suppressing damage to the surface of an image display member even when an impact is applied to the image display device is being studied.

For example, an impact absorbing film having a support layer and an adhesive layer in order in the thickness direction has been proposed (see, for example, Patent Document 1 below). The shock absorption film described in the comparative example of Patent Document 1 discloses a configuration in which the support layer is a thick PET film.

Japanese Unexamined Patent Publication No. 2020-060689

However, the impact absorption film described in Patent Literature 1 has a problem that the impact absorption per unit thickness is insufficient. In this case, although the thickness can be reduced, the shock absorption property is not excellent, or the shock absorption property is excellent but the thickness is increased.

In particular, the shock absorbing film is required to have durability against various impacts such as a ball impact and a pen impact.

The present invention provides an image display device with excellent optical reliability and excellent durability against various impacts and a manufacturing method thereof.

The present invention (1) is an image display device comprising a window member, a shock absorbing member, a panel member, and a protective member in order on one side in the thickness direction, wherein the shock absorbing member has a total light transmittance of 60% or more, and the weight Per unit thickness of the shock absorbing member divided by the thickness of the shock absorbing member, the ball shock absorption rate of the shock absorbing member obtained by dropping a stainless steel ball of 10 g and having a diameter of 13 mm from a height of 20 cm onto the shock absorbing member The ball shock absorption rate is 0.27%/μm or more, and the pen shock absorption rate of the shock absorbing member obtained by dropping a ballpoint pen having a weight of 7 g and a ball diameter of 0.7 mm at the tip from a height of 20 cm to the shock absorbing member is defined as the shock absorption rate of the ball pen. A pen impact absorption rate per unit thickness of the shock absorbing member, divided by the thickness of the member, is 0.10%/μm or more.

In this image display device, the shock absorbing member has a total light transmittance of 60% or more. Therefore, the image display device has high optical reliability.

Further, in this image display device, the ball impact absorption per unit thickness of the shock absorbing member is 0.27%/μm or more, and the pen impact absorption rate per unit thickness of the shock absorbing member is 0.10%/μm or more. Therefore, the image display device is excellent in durability against impact with a ball and impact with a pen. Therefore, the image display device has excellent durability against various impacts.

In a test in which the image display device is bent so that the window member faces outward, the present invention (2) shows that the panel is bent 200,000 times so that the distance between the two outward facing surfaces of the window member is 8 mm. The image display device according to (1), wherein the member is not damaged.

In this image display device, the panel member is not damaged even when the image display device is bent 200,000 times in the above bending test. Therefore, the image display device is excellent in bending resistance.

In the present invention (3), the image described in (1) or (2), wherein the shock absorbing member includes a first adhesive layer, a base material, and a second adhesive layer in order toward one side in the thickness direction. Include a display device.

The present invention (4) includes the image display device according to (3), wherein the first adhesive layer is in contact with the window member, and the second adhesive layer is in contact with the panel member.

In this image display device, the first adhesive layer adheres to the window member. A second adhesive layer adheres to the panel member. Therefore, the window member adheres to the panel member via the impact absorbing member. And since the impact absorbing member provided with the base material, and the first adhesive layer and the second adhesive layer interposed therebetween adheres to the window member and the panel member, the bending resistance is further excellent.

In the present invention (5), the shear storage modulus (G ') at 25 ° C. of the second adhesive layer is equal to or higher than the shear storage modulus (G ') at 25 ° C. of the first adhesive layer, (3 ) or the image display device described in (4).

In the present invention (6), the image display device according to any one of (3) to (5), wherein the first adhesive layer has a shear storage modulus (G') at 25°C of 0.01 MPa or more and 0.05 MPa or less. includes

In the present invention (7), the image display device according to any one of (3) to (6), wherein the second adhesive layer has a shear storage modulus (G') at 25°C of 0.10 MPa or more and 0.15 MPa or less. includes

In the present invention (8), the value obtained by subtracting the shear storage modulus (G') at 25°C of the first adhesive layer from the shear storage modulus (G') at 25°C of the second adhesive layer is 0.06 MPa. The above image display device according to any one of (3) to (7) is included.

The present invention (9) includes the image display device according to any one of (3) to (8), wherein the above description is singular.

In addition, in this image display device, since the substrate is single, the configuration is simple.

The present invention (10) includes the image display device according to any one of (3) to (8), further comprising a plurality of substrates and an intermediate adhesive layer disposed between the plurality of substrates.

In this image display device, there are a plurality of substrates. In addition, the image display device further includes an intermediate adhesive layer disposed between the plurality of substrates. Therefore, it is easy to design various shock absorbing performance according to use and purpose.

In the present invention (11), the shear storage modulus (G′) of the middle adhesive layer at 25° C. is greater than or equal to the shear storage modulus (G′) of the first adhesive layer at 25° C., and that of the second adhesive layer The image display device according to (10), wherein the shear storage modulus (G') or less at 25°C is included.

In the present invention (12), the shear storage modulus (G′) at 25° C. of the middle adhesive layer is higher than the shear storage modulus (G′) at 25° C. of the first adhesive layer, and the 25° C. It includes the image display device according to (10) or (11), which is lower than the shear storage modulus (G') at °C.

In the present invention (13), the image display device according to any one of (10) to (12), wherein the intermediate adhesive layer has a shear storage modulus (G') at 25°C of more than 0.05 MPa and less than or equal to 0.15 MPa. include

In the present invention (14), the substrate includes a first substrate in contact with the first adhesive layer and a second substrate in contact with the second adhesive layer, the first substrate is thinner than the second substrate, The image display device according to any one of (10) to (13) is included.

In the present invention (15), the substrate includes a first substrate in contact with the first adhesive layer and a second substrate in contact with the second adhesive layer, the first substrate is thicker than the second substrate, The image display device according to any one of (10) to (13) is included.

The present invention (16) includes the image display device according to any one of (3) to (15), wherein the ratio of the thickness of the base material to the thickness of the shock absorbing member is 0.20 or more and 0.35 or less.

The present invention (17) includes the image display device according to any one of (3) to (16), wherein the material of the above description is a cycloolefin resin and/or a polyester resin.

The present invention (18) includes the image display device described in (17), wherein the olefin resin is a cycloolefin resin.

The present invention (19) includes the image display device described in (17), wherein the polyester resin is polyethylene terephthalate.

The present invention (20) is a method for manufacturing an image display device comprising a window member, a first adhesive layer, a base material, a second adhesive layer, a panel member, and a protective member in order on one side in the thickness direction, A first step of starting a trial product, a second step of evaluating the trial product, a third step of determining manufacturing conditions based on the evaluation, and a fourth step of manufacturing a product based on the manufacturing conditions The second step includes a fifth step of producing a first sample and a second sample from the prototype, and a sixth step of dropping a ball on the first sample and dropping a ballpoint pen on the second sample. and a seventh step of determining whether or not there is damage to the first sample and the second sample after the sixth step, and in the third step, if the trial product is evaluated as having damage to the first sample, , When the manufacturing condition is changed so that the total thickness of the first adhesive layer and the second adhesive layer is thicker, and the prototype is evaluated as having damage to the second sample, the thickness of the substrate is made thicker It includes a manufacturing method of an image display device, which is changed to do so.

According to this manufacturing method, since the manufacturing conditions are determined by evaluating the prototype, the yield can be improved.

The image display device of the present invention has excellent optical reliability and excellent durability against various impacts.

The production method of the present invention can improve yield.

1 is a cross-sectional view of an organic EL display device as a first embodiment of an image display member of the present invention.
2A and 2B illustrate the ball drop test. Fig. 2a calculates the impact of the laminated body of the window member and the impact absorbing member. Figure 2b obtains the impact load of only the window member.
3A and 3B illustrate the pen drop test. Fig. 3a calculates the impact load of the laminate of the window member and the shock absorbing member. 3B calculates the impact load of only the window member.
4A and 4B illustrate bending of the organic EL display device. 4A is an organic EL display device before bending. 4B is an organic EL display device after bending.
5 is a process chart of a manufacturing method of an organic EL display device.
6 is a process chart of a second process.
7 is a ball drop test for the first sample.
8 is a pen drop test for the second sample.
9 is an organic EL display device according to a second embodiment.
10 is an organic EL display device of a modification of the second embodiment.
11 is an organic EL display device of a modified example.
12 is a graph showing the shear storage modulus (G′) of the first adhesive layer and the second adhesive layer of Examples 1 to 6;

[First Embodiment]

An organic electroluminescent display device as a first embodiment of the image display member of the present invention will be described with reference to FIG. 1 . Hereafter, the organic electroluminescent display device is simply abbreviated as 'organic EL display device'. In FIG. 1 , in the organic EL display device 1, the front side is the user's viewing side, and is the other side in the thickness direction. The back side is the side opposite to the front side, and is an example of one side in the thickness direction.

As shown in Fig. 1, the organic EL display device 1 extends in the plane direction. The face direction is orthogonal to the front and back directions. The organic EL display device 1 has, for example, a flat plate shape. The organic EL display device 1 has a front surface 21 and a rear surface 22 . Both the front surface 21 and the back surface 22 are flat. The surface 21 is a surface that can be visually recognized by the user. The organic EL display device 1 is bendable about the middle portion 24, for example. The middle part 24 is located between the two sides 23 . The two sides 23 oppose each other at intervals in the plane direction.

The organic EL display device 1 includes a window member 2, an impact absorbing member 3, an organic EL panel member 4, and a protective member 5 in order toward the rear side. On the other hand, in this embodiment, the organic EL display device 1 is not provided with a polarizer. A polarizer is normally disposed between the window member 2 and the organic EL panel member 4 . The organic EL display device 1 of the first embodiment includes an impact absorbing member 3 instead of a polarizer. The organic EL display device 1 preferably includes only a window member 2, an impact absorbing member 3, an organic EL panel member 4, and a protective member 5.

The window member 2 forms the surface 21 in the organic EL display device 1 . The window member 2 extends in the plane direction. The window member 2 is provided with, for example, a hard coat layer 6 (see phantom line) and a window film 7 in order toward the rear side. Alternatively, the window member 2 includes only the window film 7 .

If the material of the window film 7 is resin, it is preferable that the hard coat layer 6 is provided to the window member 2. The hard coat layer 6 is a protective member that suppresses damage caused by rubbing on the surface 21 of the organic EL display device 1 . The hard coat layer 6 includes, for example, a cured product of a curable composition or a molded product of a thermoplastic composition. The thickness of the hard coat layer 6 is, for example, 5 μm or more, preferably 7 μm or more, and, for example, 30 μm or less. The hard coat layer 6 is described in Unexamined-Japanese-Patent No. 2020-064236, for example. On the other hand, when the material of the window film 7 is glass, the hard coat layer 6 is not provided on the window member 2 .

When the window member 2 includes the hard coat layer 6, the window film 7 is disposed on the back surface of the hard coat layer 6. Specifically, the window film 7 is in contact with the entire back surface of the hard coat layer 6 . When the window member 2 does not have the hard coat layer 6, the window film 7 forms the surface 21 of the organic EL display device 1. As a material of the window film 7, resin and glass are mentioned, for example. Examples of the resin include polyimide resins, acrylic resins, and polycarbonate resins. The thickness of the window film 7 is, for example, 1 μm or more and, for example, 100 μm or less. A commercial item can be used for the window film 7. As a commercial item, "CPI" (made by KOLON) and G-LEAF (made by Nippon Electric Glass Co., Ltd.) are mentioned, for example. The window film 7 is described in Unexamined-Japanese-Patent No. 2020-064236, for example.

The total light transmittance of the window member 2 is, for example, 80% or more, preferably 85% or more. The upper limit of the total light transmittance of the window member 2 is not particularly limited. The upper limit of the total light transmittance of the window member 2 is, for example, 100%. The total light transmittance of the window member 2 is measured based on JIS K 7375-2008. The total light transmittance of the other members thereafter is also measured in the same manner as above.

The shock absorbing member 3 extends in the plane direction. The shock absorbing member 3 is disposed on the rear surface of the window member 2 . Specifically, the shock absorbing member 3 is in contact with the entire back surface of the window member 2 . The impact absorbing member 3 is disposed at the same position as the polarizer of the conventional organic EL display device. The shock absorbing member 3 includes a first adhesive layer 8, a substrate 9, and a second adhesive layer 10 in this order toward the rear side. In the first embodiment, the shock absorbing member 3 preferably includes only the first adhesive layer 8, the substrate 9, and the second adhesive layer 10.

The first adhesive layer 8 extends in the plane direction. In the first embodiment, the first adhesive layer 8 is singular. The first adhesive layer 8 forms the surface of the shock absorbing member 3 . The first adhesive layer 8 is disposed on the back surface of the window film 7 . Specifically, the first adhesive layer 8 is in contact with the entire back surface of the window film 7 . Details of the material and physical properties of the first adhesive layer 8 will be described later.

The substrate 9 extends in the plane direction. In the first embodiment, the substrate 9 is singular. The substrate 9 has a sheet shape. The substrate 9 is disposed on the back side of the first adhesive layer 8 . Specifically, the substrate 9 is in contact with the entire back surface of the first adhesive layer 8 . Details of the material and physical properties of the substrate 9 will be described later.

The second adhesive layer 10 extends in the plane direction. The second adhesive layer 10 is singular. The second adhesive layer 10 forms the back surface of the shock absorbing member 3 . The second adhesive layer 10 is disposed on the back surface of the substrate 9 . Specifically, the second adhesive layer 10 is in contact with the entire back surface of the substrate 9 . Details of the material and physical properties of the second adhesive layer 10 will be described later.

The thickness of the shock absorbing member 3 is not particularly limited. The thickness of the impact absorbing member 3 is, for example, 40 μm or more, preferably 70 μm or more, and, for example, 200 μm or less, preferably 150 μm or less, and more preferably 100 μm or less. When the thickness of the shock absorbing member 3 is equal to or less than the above upper limit, it is easy to increase the pen shock absorption rate per unit thickness.

This shock absorbing member 3 has a total light transmittance of 60% or more, a ball impact absorption per unit thickness of 0.27%/μm or more, and a pen impact absorption rate per unit thickness of 0.10%/μm or more.

If the total light transmittance of the shock absorbing member 3 is less than 60%, the visibility is reduced. The total light transmittance of the shock absorbing member 3 is preferably 65% or more, more preferably 70% or more, still more preferably 80% or more, particularly preferably 85% or more, and most preferably 90% or more. The upper limit of the total light transmittance of the shock absorbing member 3 is not particularly limited. The upper limit of the total light transmittance of the shock absorbing member 3 is, for example, 100% or 99%. In addition, if the total light transmittance of the laminate of the window member 2 and the shock absorbing member 3 is 60% or more, it can be said that the total light transmittance of the window member 2 is 60% or more. Other lower limit values can also be defined in the same way as when the lower limit value is 60%.

The ball impact absorption rate per unit thickness of the shock absorbing member 3 is 0.27%/μm or more.

In contrast, if the ball impact absorption per unit thickness of the shock absorbing member 3 is less than 0.27%/μm, the impact resistance to balls per unit thickness is low. Therefore, an efficient impact absorption effect on the ball 90 (see Fig. 7) cannot be obtained. The ball impact absorption per unit thickness of the shock absorbing member 3 is preferably 0.30%/μm or more, more preferably 0.32%/μm or more, still more preferably 0.34%/μm or more.

The ball impact absorption rate per unit thickness of the shock absorbing member 3 is a value obtained by dividing the ball impact absorption rate of the shock absorbing member 3 by the thickness of the shock absorbing member 3 . As shown in Fig. 2A, the ball shock absorption rate of the shock absorbing member 3 can be obtained by dropping a stainless steel ball 90 having a weight of 10 g and a diameter of 13 mm from a height of 20 cm onto the shock absorbing member 3.

The ball shock absorption rate of the shock absorbing member 3 is not particularly limited. The ball impact absorption rate of the shock absorbing member 3 is, for example, 20% or more, preferably 25% or more, more preferably 30% or more, still more preferably 40% or more, and particularly preferably 50% or more. The upper limit of the ball shock absorption rate of the shock absorbing member 3 is not particularly limited. The upper limit of the ball shock absorption rate of the shock absorbing member 3 is, for example, 90% or 85%.

The pen shock absorption rate per unit thickness of the shock absorbing member 3 is 0.10%/μm or more.

In contrast, when the pen impact absorption per unit thickness of the shock absorbing member 3 is less than 0.10%/μm, the impact resistance to the pen per unit thickness is low. Therefore, an efficient impact absorption effect for the pen (see Fig. 8) cannot be obtained. The pen impact absorption rate per unit thickness of the shock absorbing member 3 is preferably 0.11%/μm or more, more preferably 0.12%/μm or more, still more preferably 0.13%/μm or more, and furthermore 0.14%/μm or more. , 0.15%/μm or more, 0.17%/μm or more, 0.19%/μm or more, 0.20%/μm or more, 0.22%/μm or more are suitable.

The pen shock absorption rate per unit thickness of the shock absorbing member 3 is the value obtained by dividing the pen shock absorption rate of the shock absorbing member 3 by the thickness of the shock absorbing member 3. As shown in Fig. 3A, the pen shock absorption rate of the shock absorbing member 3 is such that a pen 95 having a weight of 7 g and a ball 96 at the tip having a diameter of 0.7 mm is placed on the shock absorbing member 3 from a height of 20 cm. You can save it by dropping it.

The pen shock absorption rate of the shock absorbing member 3 is not particularly limited. The pen shock absorption rate of the shock absorbing member 3 is, for example, 5% or more, preferably 6% or more, more preferably 7% or more, still more preferably 8% or more, particularly preferably 9% or more, and further , 10% or more, 11% or more, 15% or more, 20% or more, 25% or more, 30% or more are suitable. The upper limit of the pen shock absorption rate of the shock absorbing member 3 is not particularly limited. The upper limit of the pen shock absorption rate of the shock absorbing member 3 is, for example, 85% or 80%.

The organic EL panel member 4 shown in FIG. 1 is an example of a panel member. The organic EL panel member 4 extends in the plane direction. The organic EL panel member 4 is disposed on the back side of the shock absorbing member 3 . The organic EL panel member 4 is in contact with the entire back surface of the shock absorbing member 3 . Specifically, the organic EL panel member 4 is in contact with the second adhesive layer 10 . The organic EL panel member 4 includes a thin film encapsulation layer 11 and a panel body 12 .

The thin film encapsulation layer 11 is called TFE (Thin Film Encapsulation). The thin film encapsulation layer 11 extends in the plane direction. The thin film encapsulation layer 11 forms the surface of the organic EL panel member 4 . The thin film encapsulation layer 11 is disposed on the back surface of the second adhesive layer 10 . Specifically, the thin film encapsulation layer 11 is in contact with the entire back surface of the second adhesive layer 10 . The thin film encapsulation layer 11 has high hardness and low toughness. The material of the thin film encapsulation layer 11 is not particularly limited. Specifically, as a material of the thin film sealing layer 11, an inorganic compound and resin are mentioned, for example.

As an inorganic compound, silicon nitride, silicon oxynitride, carbon nitride, and aluminum oxide are mentioned, for example.

The panel body 12 extends in the plane direction. The surface of the panel body 12 is coated with the thin film encapsulation layer 11 . The panel body 12 forms the back side of the organic EL panel member 4 . Although not shown, the panel main body 12 includes a substrate, two electrodes, and an organic EL layer interposed between the two electrodes.

The thickness of the organic EL panel member 4 is, for example, 40 μm or less, preferably 30 μm or less, more preferably 20 μm or less, and, for example, 10 μm or more.

The protective member 5 extends in the plane direction. The protective member 5 is disposed on the back surface of the organic EL panel member 4 . Specifically, the protection member 5 is in contact with the entire back surface of the organic EL panel member 4 . The protective member 5 protects the organic EL panel member 4 from the rear side. The protective member 5 forms the back surface 22 of the organic EL display device 1 . The protection member 5 is provided with the front side adhesive layer 13 and the protection base material 14 in order toward the back side. In addition, the protective member 5 may be provided with the back side adhesive layer 15 and the metal plate 16 in this order, as shown by a virtual line, for example on the back side of the protective base material 14. In this case, the protective member 5 includes a front side adhesive layer 13, a protective substrate 14, a back side adhesive layer 15, and a metal plate 16 in this order facing the rear side.

The surface adhesive layer 13 is disposed on the back surface of the panel body 12 . Specifically, the surface adhesive layer 13 is in contact with the entire back surface of the panel body 12 . In addition, the surface adhesive layer 13 forms the surface of the protection member 5 . The material of the surface adhesive layer 13 is not particularly limited. The front side adhesive layer 13 may contain the same material as the first adhesive layer 8 described later. The thickness of the surface adhesive layer 13 is, for example, 1 μm or more, preferably 5 μm or more, and, for example, 50 μm or less, preferably 40 μm or less.

The protective substrate 14 is disposed on the back surface of the front side adhesive layer 13 . Specifically, the protective substrate 14 is in contact with the entire back surface of the protective substrate 14 . The material of the protective substrate 14 is not particularly limited. The protective substrate 14 may contain the same material as the substrate 9 . The thickness of the protective substrate 14 is, for example, 5 μm or more, preferably 10 μm or more, and, for example, 250 μm or less, preferably 100 μm or less.

When the protection member 5 includes the adhesive back layer 15 and the metal plate 16, the adhesive back layer 15 is disposed on the back surface of the protective substrate 14. Specifically, the adhesive backing layer 15 is in contact with the entire back surface of the protective substrate 14 . The back side adhesive layer 15 may contain the same material as the first adhesive layer 8 described later. The thickness of the back-side adhesive layer 15 is, for example, 10 μm or more, preferably 30 μm or more, and, for example, 100 μm or less, preferably 50 μm or less.

The metal plate 16 extends in the plane direction. The metal plate 16 forms the back surface 22 of the organic EL display device 1 . The metal plate 16 is disposed on the back side of the adhesive backing layer 15 . Specifically, the metal plate 16 is in contact with the entire back surface of the adhesive backing layer 15 . As a material of the metal plate 16, metal is mentioned, for example. Examples of the metal include aluminum, titanium, steel, 42 alloy, stainless steel, and magnesium alloy. As the metal, stainless steel is preferably used. The thickness of the metal plate 16 is, for example, 5 μm or more, preferably 10 μm or more, more preferably 70 μm or more, and, for example, 200 μm or less.

The thickness of the protection member 5 is, for example, 20 μm or more, preferably 25 μm or more, and, for example, 1,000 μm or less, preferably 500 μm or less.

As shown in Figs. 4A and 4B, in a test in which the organic EL display device 1 is bent so that the window member 2 faces outward, the distance between the aforementioned surfaces 21 of the window member 2 is 8 mm. Even if it is bent 200,000 times so as to be, the organic EL panel member 4 is preferably not damaged.

If the organic EL panel member 4 is not damaged by the above number of bendings, the organic EL display device 1 can suppress breakage of the thin film encapsulation layer 11 after bending.

Preferably, in a test in which the organic EL display device 1 is bent so that the window member 2 faces outward, even if the window member 2 is bent 200,000 times so that the gap between the surface 21 is 6 mm, Panel members are not damaged. Therefore, this organic EL display device 1 can suppress breakage of the thin film encapsulation layer 11 after bending.

[Details of shock absorbing member 3]

The modulus of elasticity, material and thickness of the shock absorbing member 3 will be described below.

[modulus of elasticity]

The shear storage modulus (G') of each of the second adhesive layer 10 and the first adhesive layer 8 is not particularly limited. The shear storage modulus (G') of the second adhesive layer 10 at 25°C is preferably equal to or higher than the shear storage modulus (G') of the first adhesive layer 8 at 25°C. The shear storage modulus (G') of the second adhesive layer 10 at 25°C is more preferably higher than the shear storage modulus (G') of the first adhesive layer 8 at 25°C. The shear storage modulus (G') of each of the first adhesive layer 8 and the second adhesive layer 10 is measured using a viscoelasticity measuring device. The heating rate was 5°C/min and the frequency was 1 Hz. Details are described in later examples. In addition, when the shear storage modulus (G') of the second adhesive layer 10 is the same as the shear storage modulus (G') of the first adhesive layer 8, the examples are plotted on the thick line shown in FIG. 12 . When the shear storage modulus (G') of the second adhesive layer 10 is higher than the shear storage modulus (G') of the first adhesive layer 8, the embodiment is plotted in the area above the left slant from the thick line shown in FIG. 12 .

If the shear storage modulus (G') of the second adhesive layer 10 and the first adhesive layer 8, respectively, satisfies the above preferred relationship, the organic EL display device 1 has a ball per unit thickness The impact resistance is further excellent, and the impact resistance to the pen per unit thickness is further superior. Furthermore, the organic EL display device 1 is further excellent in bending resistance.

More specifically, the value obtained by subtracting the shear storage modulus (G′) at 25° C. of the first adhesive layer 8 from the shear storage modulus (G′) at 25° C. of the second adhesive layer 10 is, For example, it is 0.03 MPa or more, Preferably it is 0.06 MPa or more. The upper limit of the above value is not limited. The upper limit of the above value is, for example, 0.15 MPa. When the above value is equal to or greater than the above lower limit, the organic EL display device 1 is further excellent in ball impact resistance per unit thickness. In addition, the region where the above value is 0.06 MPa or more includes an area above the thin solid line shown in FIG. 12 and above the left slant of the solid line.

The shear storage modulus (G') of the first adhesive layer 8 at 25°C is, for example, 0.15 MPa or less, preferably 0.10 MPa or less, and more preferably 0.05 MPa or less. The lower limit of the shear storage modulus (G′) of the first adhesive layer 8 at 25° C. is not limited. The lower limit of the shear storage modulus (G') of the first adhesive layer 8 at 25°C is, for example, 0.01 MPa. When the shear storage modulus (G′) of the first adhesive layer 8 is equal to or less than the above upper limit, the organic EL display device 1 has excellent ball impact resistance per unit thickness and pen resistance per unit thickness. Excellent impact resistance. In addition, the organic EL display device 1 is excellent in bending resistance. When the shear storage elastic modulus (G') of the first adhesive layer 8 is equal to or greater than the lower limit described above, the shock absorbing member 3 can be reliably shaped.

The shear storage modulus (G') of the second adhesive layer 10 at 25°C is, for example, 0.05 MPa or more, preferably 0.10 MPa or more. The upper limit of the shear storage modulus (G') of the second adhesive layer 10 at 25°C is not limited. The upper limit of the shear storage modulus (G′) of the second adhesive layer 10 at 25° C. is 0.15 MPa. When the shear storage modulus (G′) of the second adhesive layer 10 is equal to or greater than the above lower limit, the organic EL display device 1 has excellent impact resistance per unit thickness and excellent impact resistance to a pen per unit thickness. do. In addition, the organic EL display device 1 is excellent in bending resistance. When the shear storage elastic modulus (G') of the second adhesive layer 10 is equal to or less than the above upper limit, the shock absorbing member 3 can sufficiently absorb an external force.

The total light transmittance of each of the first adhesive layer 8 and the second adhesive layer 10 is, for example, 80% or more, preferably 85% or more. The upper limit of the total light transmittance of each of the first adhesive layer 8 and the second adhesive layer 10 is not particularly limited. The upper limit of the total light transmittance of each of the first adhesive layer 8 and the second adhesive layer 10 is, for example, 100%.

The tensile modulus (E) of the substrate 9 at 25°C is, for example, 0.1 GPa or more, preferably 1 GPa or more, and more preferably 2 GPa or more. When the tensile elastic modulus (E) of the base material 9 is equal to or greater than the above lower limit, the ball impact resistance per unit thickness of the organic EL display device 1 and the impact resistance per unit thickness per unit thickness of the organic EL display device 1 are excellent. In addition, the organic EL display device 1 is excellent in bending resistance.

The tensile modulus E of the substrate 9 is, for example, 15 GPa or less, preferably 5 GPa or less, and more preferably 1 GPa or less. When the tensile modulus E of the substrate 9 is equal to or less than the above upper limit, the ball impact resistance per unit thickness is excellent.

The tensile modulus (E) of the substrate 9 is measured using a tensile tester. Details of the measurement of the tensile modulus E of the substrate 9 will be described in later examples.

The total light transmittance of the substrate 9 is, for example, 80% or more, preferably 85% or more. The upper limit of the total light transmittance of the substrate 9 is, for example, 100%.

[ingredient]

The first adhesive layer 8 and the second adhesive layer 10 include materials capable of satisfying the above physical properties. Examples of the material include acrylic adhesives, rubber adhesives, vinylalkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, fluorine adhesives, epoxy adhesives, and polyether adhesives. Preferably, an acrylic adhesive is used.

As an acrylic adhesive, the crosslinked body of an acrylic base polymer is mentioned, for example. An acrylic base polymer can be obtained by polymerizing monomer components. The monomer component contains, for example, a (meth)acrylate having an alkyl moiety of 1 to 24 carbon atoms as a main component. (Meth)acrylate means methacrylate and/or acrylate.

The definition and usage of the above (meth)acrylate are as follows. The alkyl moiety has a linear or branched chain. Examples of the (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl ( Meth)acrylate, pentyl(meth)acrylate, isopentyl(meth)acrylate, hexyl(meth)acrylate, isohexyl(meth)acrylate, isoheptyl(meth)acrylate, 2-ethylhexyl(meth)acrylate Acrylate, Octyl(meth)acrylate, Isooctyl(meth)acrylate, Nonyl(meth)acrylate, Isononyl(meth)acrylate, Decyl(meth)acrylate, Isodecyl(meth)acrylate, Dodecyl (meth)acrylate, tridecyl(meth)acrylate, tetradecyl(meth)acrylate, hexadecyl(meth)acrylate, octadecyl(meth)acrylate, icosyl(meth)acrylate, docosyl(meth)acrylate ) acrylate, and tetracosyl (meth)acrylate. Preferably, from the viewpoint of preparing the relatively hard second adhesive layer 10, (meth)acrylates having an alkyl moiety of 1 to 4 carbon atoms are used.

Preferably, from the viewpoint of preparing the relatively soft first adhesive layer 8, (meth)acrylates having an alkyl moiety of 6 to 24 carbon atoms are used. The proportion of (meth)acrylate in the monomer component is, for example, 80% by mass or more, preferably 90% by mass or more, and, for example, 100% by mass or less, preferably 99.5% by mass or less.

The monomer component also contains a functional group-containing (meth)acrylate as an optional component. Examples of functional group-containing (meth)acrylates include hydroxyl group-containing (meth)acrylates and amide group-containing (meth)acrylates. Examples of the hydroxyl group-containing (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Examples of the amide group-containing (meth)acrylate include (meth)acrylamide and dimethyl (meth)acrylamide. In addition, the amide group-containing (meth)acrylate may include an amide group-containing (meth)acrylate in the molecule. Examples of (meth)acrylates containing an amide group in the molecule include N-vinyl-2-pyrrolidone. The proportion of the functional group-containing (meth)acrylate in the monomer component is, for example, 1% by mass or more, preferably 5% by mass or more, and, for example, 25% by mass or less, preferably 20% by mass or less.

The monomer component can be polymerized, for example in the presence of a chain transfer agent. As a chain transfer agent, a thiol compound is mentioned, for example. Examples of the thiol compound include α-thioglycerol. The mass ratio of the chain transfer agent is, for example, 1 part by mass or more and, for example, 10 parts by mass or less with respect to 100 parts by mass of the monomer component.

A crosslinked product can be obtained by mixing a crosslinking agent with an acrylic base polymer and reacting the crosslinking agent. Examples of the crosslinking agent include isocyanate crosslinking agents, silane coupling agents, peroxides, and (meth)acrylates having a plurality of (meth)acryloyl groups. Examples of the isocyanate crosslinking agent include a modified trimethylolpropane of xylylene diisocyanate and a modified trimethylolpropane of tolylene diisocyanate. As a silane coupling agent, the silane coupling agent containing an epoxy group is mentioned, for example. Examples of the epoxy group-containing silane coupling agent include 3-glycidoxypropyltrimethoxysilane. Examples of peroxides include organic peroxides. As an organic peroxide, benzoyl peroxide is mentioned, for example. Examples of the (meth)acrylate having a plurality of (meth)acryloyl groups include hexanediol (meth)acrylate. These may be used alone or in combination. The mass ratio of the crosslinking agent is, for example, 0.1 parts by mass or more, and, for example, 2 parts by mass or less, based on 100 parts by mass of the acrylic base polymer.

Along with the formulation of the crosslinking agent, additives may be added to the acrylic base polymer. An oligomer is mentioned as an additive. As an oligomer, a (meth)acrylic oligomer is mentioned, for example. The weight average molecular weight of the (meth)acrylic oligomer is, for example, 1,000 or more, preferably 2,000 or more, and, for example, 30,000 or less, preferably 10,000 or less. The weight average molecular weight of the (meth)acrylic oligomer is based on standard polystyrene conversion by GPC. A (meth)acrylic oligomer can be obtained by polymerizing a monomer component. The monomer component includes the above-described (meth)acrylate having an alkyl moiety of 1 to 24 carbon atoms and an alicyclic (meth)acrylate having an alicyclic alkyl (cycloaliphatic alkyl) moiety of 1 to 24 carbon atoms. Examples of the alicyclic alkyl moiety include monocyclic and polycyclic. Examples of monocyclic alicyclic (meth)acrylates include cycloalkyl (meth)acrylates. Examples of the cycloalkyl (meth)acrylate include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, and cyclooctyl (meth)acrylate. Examples of polycyclic alicyclic (meth)acrylates include isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and tricyclopentanyl (meth)acrylate. The proportion of (meth)acrylate in the monomer component is, for example, 10% by mass or more, preferably 20% by mass or more, and, for example, 70% by mass or less, preferably 45% by mass or less. The proportion of the alicyclic (meth)acrylate in the monomer component is, for example, 30% by mass or more, preferably 55% by mass or more, and, for example, 90% by mass or less, preferably 80% by mass or less.

The glass transition temperature of the oligomer is, for example, 20°C or higher, preferably 50°C or higher, more preferably 80°C or higher, and, for example, 150°C or lower. The glass transition temperature of an oligomer is calculated by the Fox equation.

The mass ratio of the oligomer is, for example, 0.01 part by mass or more, and, for example, 1 part by mass or less, with respect to 100 parts by mass of the acrylic base polymer.

The material of the substrate 9 includes a material that can satisfy the above physical properties. As a material of the base material 9, resin is mentioned, for example. Resin may be used alone or in combination. Examples of the resin include olefin resins, polyester resins, acrylic resins, polycarbonate resins, polyethersulfone resins, polyarylate resins, melamine resins, polyamide resins, polyimide resins, cellulose resins, and polystyrene resins. . As the resin, olefin resins, polyester resins, acrylic resins, polycarbonate resins, polyethersulfone resins, polyarylate resins, melamine resins, cellulose resins, and polystyrene resins are preferably used. As the resin, olefin resins and polyester resins are more preferably used.

As the olefin resin, for example, polyethylene, polypropylene and cycloolefin polymer (COP) can be mentioned. As an olefin resin, COP is mentioned preferably. COP is a polymer of monomeric components comprising cycloolefins. As a cycloolefin, norbornene is mentioned, for example.

Examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. Polyester resins include, for example, soft polyester resins (transparent soft polyester resins). As the polyester resin, PET is preferably used.

As a material of the base material 9, COP is mentioned especially preferably. COP can increase pen impact absorption per unit thickness compared to PET.

A commercial item can be used for the base material 9. Commercially available products include, for example, the Lumirror series (substrate made from PET, manufactured by Toray), Zeonoa series (substrate made from COP, manufactured by Zeon, Japan), and OKY series (substrate made of transparent soft polyester resin, manufactured by Bell Polyester Products, Inc.) ) can be heard.

[thickness]

The respective thicknesses of the first adhesive layer 8, the substrate 9, and the second adhesive layer 10 are not particularly limited.

The thickness of each of the first adhesive layer 8 and the second adhesive layer 10 is, for example, 1 μm or more, preferably 5 μm or more, and, for example, 50 μm or less, preferably 40 μm or less. The second adhesive layer 10 may have the same thickness as the first adhesive layer 8 or may have a different thickness from the first adhesive layer 8 .

The thickness of the substrate 9 is, for example, 5 μm or more, preferably 10 μm or more, and, for example, 100 μm or less, preferably 75 μm or less, more preferably 50 μm or less, still more preferably less than 50 μm. , particularly preferably 45 μm or less, most preferably 30 μm or less.

The ratio of the thickness of the substrate 9 to the thickness of the shock absorbing member 3 is, for example, 0.10 or more, preferably 0.20 or more, and also, for example, 0.70 or less, preferably 0.60 or less, more preferably 0.40 or less; More preferably, it is 0.35 or less. When the ratio of the thickness of the substrate 9 is equal to or greater than the lower limit described above, the bending resistance is excellent. When the ratio of the thickness of the substrate 9 is equal to or less than the above upper limit, the pen impact absorption per unit thickness is high.

[Production of organic EL display device 1]

The organic EL display device 1 can be obtained by laminating a window member 2, an impact absorbing member 3, an organic EL panel member 4, and a protective member 5.

Although not shown, the shock absorbing member 3 is prepared as a shock absorbing member with a release sheet. An impact absorbing member with a release sheet includes an impact absorbing member 3 and a release sheet laminated on the front and back surfaces thereof. The shock absorbing member 3 is prepared by peeling the release sheet of the shock absorbing member with the release sheet from the shock absorbing member 3 .

In addition, another manufacturing method for manufacturing the organic EL display device 1 using the prototype 40 will be described with reference to FIGS. 5 and 6 . As shown in FIG. 5, this method includes a first step S1, a second step S2, a third step S3, and a fourth step S4 in this order.

In the first step (S1), a trial product is started. For example, a plurality of prototypes 40 are started. Each of the plurality of prototypes 40 has, for example, the same configuration, the same thickness, and the same physical properties as each other. The plurality of prototypes 40 include, for example, a first sample 61 and a second sample 62 , and further include a third sample 63 . Prototype 40 is also a similar sample. The prototype 40 has the same structure as the organic EL display device 1 described above except for the following points. In the organic EL panel member 4 of the prototype 40, the ITO layer 35 is provided instead of the thin film encapsulation layer 11. The ITO layer 35 is configured to evaluate damage due to strain that may be imparted to the thin film encapsulation layer 11 . The ITO layer 35 includes a composite oxide of indium oxide and tin oxide (ITO). The thickness of the ITO layer 35 is, for example, 100 nm or less, preferably 70 nm or less, more preferably 50 nm or less, and, for example, 20 nm or more. By changing the thickness of the ITO layer 35, cracking against deformation can be controlled. The organic EL panel member 4 including the ITO layer 35 and the panel body 12 is a dummy panel member 44 .

In the prototype 40, for example, the first adhesive layer 8 and the second adhesive layer 10 each have the same shear storage modulus (G') at 25°C.

In the second step (S2), the prototype 40 is evaluated. 2nd process S2 is provided with 5th process S5, 6th process S6, and 7th process S7, as shown in FIG.

In the 5th process (S5), the 1st sample 61 and the 2nd sample 62 are selected from the prototype 40. The first sample 61 and the second sample 62 have the same configuration, the same thickness, and the same physical properties. Alternatively, the third sample 63 may be subjected to a bending test described later.

In the sixth step S6, a ball drop test (see Fig. 7) and a pen drop test (see Fig. 8) are performed.

As shown in FIG. 7 , in the ball drop test, the ball 90 is dropped onto the first sample 61 . The weight of the ball 90 in the ball drop test is, for example, 1 g or more, preferably 2 g or more, and, for example, 100 g or less, preferably 50 g or less. The diameter of the ball 90 in the ball drop test is, for example, 1 mm or more, preferably 2 mm or more, and, for example, 100 mm or less, preferably 50 mm or less. The material of the ball is not limited, and is, for example, metal. The drop height of the ball 90 in the ball drop test is, for example, 2 cm or more, preferably 5 cm or more, and, for example, 200 cm or less, preferably 100 cm or less.

As shown in FIG. 8 , in the pen drop test, a pen (ballpoint pen) 95 is dropped onto the second sample 62 . The pen 95 has a ball 96 at its tip.

The weight of the pen 95 in the pen drop test is, for example, 0.5 g or more, preferably 1 g or more, and, for example, 50 g or less, preferably 30 g or less. The diameter of the ball 96 in the pen drop test is, for example, 0.01 mm or more, preferably 0.1 mm or more, and, for example, 5 mm or less, preferably 1 mm or less. The drop height in the pen drop test is, for example, 2 cm or more, preferably 5 cm or more, and, for example, 200 cm or less, preferably 100 cm or less.

In the seventh step (S7), it is determined whether or not there is damage to the first sample 61 and the second sample 62.

Then, in the third step, when the prototype 40 is evaluated as having damage to the first sample 61, the total thickness of the first adhesive layer 8 and the second adhesive layer 10 is made thicker, It is determined by changing the manufacturing conditions. Moreover, in the 3rd process, when the trial product 40 is evaluated that the 2nd sample 62 has damage, it determines by changing manufacturing conditions so that the thickness of the base material 9 may be made thicker.

In the fourth step (S4), the organic EL display device 1 is manufactured based on the above manufacturing conditions.

In this way, the organic EL display device 1 is manufactured as a product.

In addition, in the seventh step (S7), when it is determined that neither of the first sample 61 and the second sample 62 is damaged, the above-described third step (S3) is skipped, that is, the manufacturing conditions are changed. Without change, the organic EL display device 1 is manufactured as a product.

[Use of organic EL display device 1]

As shown in Fig. 4A, when the user visually recognizes the entire surface 21 of the organic EL display device 1, the organic EL display device 1 is open. At this time, the surface 21 is a flat surface. The organic EL display device 1 includes an intermediate portion 24 , a first portion 17 , and a second portion 18 . The middle part 24 is located in the middle of the two sides 23. The two sides 23 include a first side 23A and a second side 23B. The first portion 17 is a region including the first side 23A. The second portion 18 is a region including the second side 23B.

As shown in FIG. 4B , the organic EL display device 1 may be bent with the middle portion 24 as the center. That is, there are cases where the organic EL display device 1 is bent and used. In this case, the intermediate portion 24 forms a corrugation. The surface 21 of the first part 17 and the surface 21 of the second part 18 face outward from each other. In this case, the back surface 22 of the first part 17 and the back surface 22 of the second part 18 are closely opposed to each other.

[Operations and effects of the first embodiment]

And, in this organic EL display device 1, the impact absorbing member 3 has a total light transmittance of 60% or more. Specifically, the total light transmittance of the impact absorbing member 3 provided in the organic EL display device 1 as a substitute for the polarizer is high. Therefore, the organic EL display device 1 has high optical reliability. In particular, since the organic EL display device 1 of the first embodiment does not include a polarizer, optical reliability is particularly high.

Further, in this organic EL display device 1, the shock absorbing member 3 has a ball impact absorption per unit thickness of 0.27%/μm or more, and a pen impact absorption rate per unit thickness of 0.10%/μm or more. Therefore, the organic EL display device 1 has excellent durability against impact with a ball and impact with a pen. Therefore, the organic EL display device 1 has excellent durability against various impacts.

Further, in a test in which the organic EL display device 1 is bent so that the window member 2 faces outward, even if the window member 2 is bent 200,000 times so that the distance between the two surfaces 21 is 8 mm, , the organic EL panel member 4 is not damaged. Therefore, the organic EL display device 1 is excellent in bending resistance.

In addition, in this organic EL display device 1, the first adhesive layer 8 adheres to the window member 2. The second adhesive layer 10 adheres to the organic EL panel member 4 . Therefore, the window member 2 adheres to the organic EL panel member 4 via the impact absorbing member 3 . Then, the shock absorbing member 3 provided with the base material 9 and the first adhesive layer 8 and the second adhesive layer 10 interposed therebetween is composed of a window member 2 and an organic EL panel member 4 ), the bending resistance is further excellent.

In addition, in this organic EL display device 1, the shear storage modulus (G') at 25°C of the second adhesive layer 10 is the shear storage modulus (G') at 25°C of the first adhesive layer 8. '), the organic EL display device 1 is excellent in impact resistance per unit thickness to a ball and impact resistance per unit thickness to a pen. Further, this organic EL display device 1 is excellent in bending resistance.

In particular, in this organic EL display device 1, the shear storage modulus (G') at 25°C of the second adhesive layer 10 is the shear storage modulus (G') at 25°C of the first adhesive layer 8. '), the organic EL display device 1 has further excellent ball impact resistance per unit thickness, and further excellent pen impact resistance per unit thickness.

Further, in this organic EL display device 1, if the shear storage modulus (G') at 25°C of the first adhesive layer 8 is 0.01 MPa or more, the shock absorbing member 3 can be reliably shaped. . When the shear storage modulus (G') at 25°C of the first adhesive layer 8 is 0.05 MPa or less, the organic EL display device 1 has excellent ball impact resistance per unit thickness.

In this organic EL display device 1, when the shear storage modulus (G') at 25°C of the second adhesive layer 10 is 0.10 MPa or more, the organic EL display device 1 has excellent bending resistance. When the shear storage elastic modulus (G') at 25°C of the second adhesive layer 10 is 0.15 MPa or less, the shock absorbing member 3 can sufficiently absorb an external force.

Further, in this organic EL display device 1, from the shear storage modulus (G') at 25°C of the second adhesive layer 10, the shear storage modulus (G') of the first adhesive layer 8 at 25°C (G ') is 0.06 MPa or more, the organic EL display device 1 is excellent in impact resistance per unit thickness to a ball and impact resistance per unit thickness to a pen. In addition, this organic EL display device 1 is also excellent in both bending resistance.

Further, in this organic EL display device 1, since the substrate 9 is single, the configuration is simple.

In addition, in this organic EL display device 1, when the ratio of the thickness of the base material 9 to the thickness of the shock absorbing member 3 is 0.20 or more, the pen has excellent impact resistance per unit thickness. When the ratio of the thickness of the base material 9 to the thickness of the shock absorbing member 3 is 0.35 or less, the ball impact absorption per unit thickness is high.

In addition, in this organic EL display device 1, when the material of the substrate 9 is an olefin resin and/or a polyester resin, the ball impact absorption rate per unit thickness and the pen impact absorption rate per unit thickness can be increased.

When the organic EL display device 1 is manufactured by the manufacturing method including the first step (S1) to the third step (S3) described above, the prototype 40 is evaluated and the manufacturing conditions are determined. can improve

[Second Embodiment]

In the following second embodiment, the same reference numerals are assigned to members and steps similar to those of the first embodiment described above, and detailed descriptions thereof are omitted. In addition, 2nd Embodiment can exhibit the same effect as 1st Embodiment other than what is mentioned specially.

As shown in FIG. 9, in 2nd Embodiment, the base material 9 is multiple. Specifically, the substrate 9 includes a first substrate 25 and a second substrate 26 . In addition, the shock absorbing member 3 further includes an intermediate adhesive layer 19 .

The first substrate 25 contacts the first adhesive layer 8 . The first substrate 25 is disposed on the back surface of the first adhesive layer 8 . The first substrate 25 does not contact the second adhesive layer 10 .

The second substrate 26 is disposed on the back side of the first substrate 25 at intervals. The second substrate 26 contacts the second adhesive layer 10 . The second substrate 26 is disposed on the surface of the second adhesive layer 10 . The second substrate 26 does not contact the first adhesive layer 8 .

The intermediate adhesive layer 19 is single in the second embodiment. The intermediate adhesive layer 19 is interposed between the first substrate 25 and the second substrate 26 . The middle adhesive layer 19 is in contact with the first substrate 25 and the second substrate 26 . Specifically, the middle adhesive layer 19 is in contact with the back surface of the first base material 25 and the surface of the second base material 26 .

This shock absorbing member 3 includes the first adhesive layer 8, the first substrate 25, the middle adhesive layer 19, the second substrate 26, and the second adhesive layer 10 on the opposite side. Equipped in order towards In the second embodiment, the shock absorbing member 3 preferably includes a first adhesive layer 8, a first substrate 25, an intermediate adhesive layer 19, a second substrate 26, and a second substrate 26. 2 It is provided with only the adhesive layer (10).

[Details of Intermediate Adhesive Layer 19]

The shear storage modulus (G') at 25°C of the middle adhesive layer 19 is not particularly limited. Preferably, the shear storage modulus (G′) of the middle adhesive layer 19 at 25° C. is equal to or greater than the shear storage modulus (G′) of the first adhesive layer 8 at 25° C., and the second adhesive layer ( 10) is less than the shear storage modulus (G') at 25°C.

The shear storage modulus (G') of the intermediate adhesive layer 19 is equal to or greater than the shear storage modulus (G') of the first adhesive layer 8, and the shear storage modulus (G') of the second adhesive layer 10 at 25°C ') or less, it can be seen that the organic EL display device 1 has excellent ball and pen impact resistance per unit thickness.

More preferably, the shear storage modulus (G') of the middle adhesive layer (19) at 25°C is higher than the shear storage modulus (G') of the first adhesive layer (8) at 25°C, and the second adhesive layer (19) has a shear storage modulus (G') at 25°C. lower than the shear storage modulus (G′) at 25° C. of layer 10. In this case, it is possible to more reliably achieve both high impact resistance per unit thickness of the ball and high bending resistance.

The shear storage modulus (G') of the middle adhesive layer 19 at 25°C is, for example, 0.01 MPa or more, preferably 0.05 MPa or more, more preferably more than 0.05 MPa, and, for example, 0.15 MPa or less, preferably is 0.10 MPa or less.

When the shear storage modulus (G') of the intermediate adhesive layer 19 exceeds the lower limit and is lower than the upper limit, the ball impact resistance per unit thickness and bending resistance are further excellent.

The thickness of the intermediate adhesive layer 19 is, for example, 1 μm or more, preferably 10 μm or more, and, for example, 40 μm or less, preferably 30 μm or less.

[Details of First Base 25 and Second Base 26]

The ratio of the total thickness of the first substrate 25 and the second substrate 26 to the thickness of the shock absorbing member 3 is the thickness of the substrate 9 to the thickness of the shock absorbing member 3 described above. Same with the ratio.

The thickness of the first substrate 25 is, for example, 1 μm or more, preferably 3 μm or more, and, for example, 50 μm or less, preferably 20 μm or less.

The thickness of the second substrate 26 is, for example, 5 or more, preferably 15 μm or more, and, for example, 100 μm or less, preferably 50 μm or less.

The first substrate 25 is thicker or thinner than the second substrate 26, for example. The first substrate 25 may have the same thickness as the second substrate 26 . Preferably, the first substrate 25 is thinner than the second substrate 26 .

When the first substrate 25 is thinner than the second substrate 26, the impact resistance per unit thickness to the ball is even more excellent.

The ratio of the thickness of the first substrate 25 to the thickness of the second substrate 26 is preferably 0.9 or less, preferably 0.7 or less. The lower limit of the ratio of the thickness of the first substrate 25 to the thickness of the second substrate 26 is, for example, 0.1 or, for example, 0.2.

On the other hand, when the first substrate 25 is thicker than the second substrate 26, the impact resistance per unit thickness to the pen is even more excellent.

The ratio of the thickness of the first substrate 25 to the thickness of the second substrate 26 is preferably 1.1 or more, preferably 1.4 or more. In addition, the upper limit of the ratio of the thickness of the 1st base material 25 with respect to the thickness of the 2nd base material 26 is 10, for example, and 5, for example.

The tensile elastic modulus (E) at 25°C of each of the first substrate 25 and the second substrate 26 is the same as the tensile elastic modulus (E) at 25°C of the substrate 9 of the first embodiment.

[Operations and effects of the second embodiment]

In this organic EL display device 1, the substrate 9 is plural. In addition, the organic EL display device 1 further includes an intermediate adhesive layer 19 disposed between the plurality of substrates 9 . Therefore, it is easy to design various shock absorbing performance according to use and purpose.

Further, in the organic EL display device 1, the shear storage modulus (G') of the intermediate adhesive layer 19 is equal to or greater than the shear storage modulus (G') of the first adhesive layer 8, and the second adhesive layer ( When the shear storage modulus (G') at 25°C or less of 10) is reached, the organic EL display device 1 has excellent ball impact resistance per unit thickness and bending resistance.

In addition, in this organic EL display device 1, the shear storage modulus (G') at 25°C of the middle adhesive layer 19 is equal to the shear storage modulus (G') at 25°C of the first adhesive layer 8. ) and is lower than the shear storage modulus (G′) at 25° C. of the second adhesive layer 10, the organic EL display device 1 has high impact resistance per unit thickness for a ball and high bending resistance. definitely compatible.

Specifically, in this organic EL display device 1, when the shear storage modulus (G') at 25°C of the middle adhesive layer 19 is more than 0.05 MPa and less than or equal to 0.15 MPa, the ball has high impact resistance per unit thickness. performance, high impact resistance per unit thickness for the pen, and high bending resistance can be achieved simultaneously.

Further, in this organic EL display device 1, when the first base material 25 is thinner than the second base material 26, it is possible to reliably achieve both high impact resistance per unit thickness for the ball and high bending resistance. .

On the other hand, in this organic EL display device 1, when the first substrate 25 is thicker than the second substrate 26, high impact resistance per unit thickness with respect to the pen is excellent.

[Modification of the second embodiment]

In the following modifications, the same reference numerals are attached to members and steps similar to those of the above-described second embodiment, and detailed descriptions thereof are omitted. In addition, the modified example can exhibit the same effect as that of the second embodiment other than those described above. In addition, 2nd Embodiment and its modified example can be combined suitably.

In this modified example, as shown in Fig. 10, the number of intermediate adhesive layers 19 is plural. Specifically, the intermediate adhesive layer 19 includes a first intermediate adhesive layer 27 and a second intermediate adhesive layer 28 . Substrate 9 further includes a third substrate 29 .

The first intermediate adhesive layer 27 contacts the first substrate 25 . However, the first intermediate adhesive layer 27 does not contact the second substrate 26 . The first intermediate adhesive layer 27 is disposed on the back surface of the first base material 25 .

The second intermediate adhesive layer 28 contacts the second substrate 26 . However, the second intermediate adhesive layer 28 does not contact the first substrate 25 . The second intermediate adhesive layer 28 is disposed on the surface of the second substrate 26 .

The third substrate 29 is disposed between the first intermediate adhesive layer 27 and the second intermediate adhesive layer 28 . The third substrate 29 is in contact with the back surface of the first intermediate adhesive layer 27 and the surface of the second intermediate adhesive layer 28 .

The shock absorbing member 3 includes a first adhesive layer 8, a first substrate 25, a first intermediate adhesive layer 27, a third substrate 29, and a second intermediate adhesive layer 28. ), the second substrate 26, and the second adhesive layer 10 are sequentially provided toward the rear side. In this modification, the shock absorbing member 3 preferably includes the first substrate 25, the first intermediate adhesive layer 27, the third substrate 29, and the second intermediate adhesive layer 28. , the second substrate 26 and the second adhesive layer 10 only.

The ratio of the total thickness of the first substrate 25, the second substrate 26, and the third substrate 29 to the thickness of the shock absorbing member 3 is It is the same as the ratio of the thickness of the base material 9.

The shear storage elastic moduli (G') at 25°C of the first intermediate adhesive layer 27 and the second intermediate adhesive layer 28 are the shear storage moduli at 25°C of the intermediate adhesive layer 19 of the second embodiment. It is the same as the elastic modulus (G').

In the first embodiment, as shown in Fig. 1, a shock absorbing member 3 composed of three layers is disclosed. In the second embodiment, as shown in Fig. 9, a shock absorbing member 3 composed of five layers is disclosed. As a modified example of the second embodiment, as shown in Fig. 10, a shock absorbing member 3 composed of seven layers is disclosed. Although not shown, the shock absorbing member 3 may consist of [2n+1 layers]. In a variant, n is a positive number of 4 or greater. In a modified example, the shock absorbing member 3 is made of [n+1] layer adhesive layer and [n] layer base material.

In the first embodiment, the shock absorbing member 3 contacts both the back surface of the window member 2 and the front surface of the organic EL panel member 4. However, the shock absorbing member 3 only needs to be disposed between the window member 2 and the organic EL panel member 4, and, for example, the organic EL panel member 4 is spaced apart from the rear surface of the shock absorbing member 3. ) may be spaced apart from the surface. In addition, the shock absorbing member 3 may be in contact with either of the above-described back surface and front surface, leaving a gap therebetween. Specifically, as shown in FIG. 11 , the shock absorbing member 3 is in contact with the rear surface of the window member 2 and is spaced apart from the organic EL panel member 4 . Specifically, the impact absorbing member 3 is disposed with the organic EL panel member 4, the polarizing film 50, and the adhesive layer 51 interposed therebetween.

The polarizing film 50 contacts the back surface of the second adhesive layer 10 . The polarizing film 50 includes a polarizer. As a polarizer, the film which carried out the dyeing process and the extending|stretching process of the hydrophilic film, the film which carried out the dehydration process of the hydrophilic film, and the film which carried out the dehydrochlorination process of the polyvinyl chloride film are mentioned, for example. As a hydrophilic film, a PVA film is mentioned, for example. The total light transmittance of the polarizer is, for example, 30% or more, preferably 35% or more, more preferably 40% or more, and, for example, 50% or less. The thickness of the polarizer is, for example, 1 μm or more, preferably 3 μm or more, and, for example, 15 μm or less, preferably 10 μm or less. A polarizer is described in Unexamined-Japanese-Patent No. 2020-149065 and Unexamined-Japanese-Patent No. 2019-218513. The polarizing film 50 is formed by laminating a protective film on the polarizer described above via an adhesive.

The adhesive layer 51 is interposed between the polarizing film 50 and the organic EL panel member 4 . The adhesive layer 51 contacts the back surface of the polarizing film 50 and the surface of the organic EL panel member 4 . The material, thickness, and physical properties of the adhesive layer 51 are the same as those of the first adhesive layer 8 or the second adhesive layer 10 .

In the organic EL display device 1 of the modified example of FIG. 11, a window member 2, an impact absorbing member 3, a polarizing film 50, an adhesive layer 51, and an organic EL panel member 4 and the protective member 5 are arranged in order toward the rear side.

Comparing the organic EL display device 1 of the first embodiment shown in FIG. 1 with the organic EL display device 1 of the modified example of FIG. 11, the organic EL display device 1 of the first embodiment has a polarizing film (50) and no adhesive layer (51). Therefore, the organic EL display device 1 of the first embodiment is excellent in optical reliability in that the polarizer in the polarizing film 50 has the aforementioned low total light transmittance.

[Example]

Examples and comparative examples are shown below, and the present invention is explained more specifically. In addition, the present invention is not limited to Examples and Comparative Examples at all. In addition, the specific numerical values such as the blending ratio (ratio), physical property value, and parameter used in the following description are the blending ratio (ratio), physical property value, It can be replaced with the upper limit (numerical value defined as 'below' or 'less than') or lower limit (numerical value defined as 'greater than' or 'exceeding') of the corresponding description, such as a parameter.

[Preparation of adhesive sheet]

PSA sheets A to D were prepared as follows.

[Adhesive Sheet A]

Lauryl acrylate (LA) 43 parts by mass, 2-ethylhexyl acrylate (2EHA) 44 parts by mass, 4-hydroxybutyl acrylate (4HBA) 6 parts by mass, N-vinyl-2-pyrrolidone (NVP) 7 parts by mass and 0.015 part by mass of "Irgacure 184" manufactured by BASF were blended, and polymerization was performed by irradiation with ultraviolet rays to obtain a base polymer composition (polymerization rate: about 10%).

Separately, 60 parts by mass of dicyclopentanyl methacrylate (DCPMA), 40 parts by mass of methyl methacrylate (MMA), 3.5 parts by mass of α-thioglycerol, and 100 parts by mass of toluene were mixed, and stirred at 70° C. for 1 hour in a nitrogen atmosphere. . Next, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) was added and reacted at 70°C for 2 hours, followed by heating to 80°C and reaction for 2 hours. Thereafter, the reaction solution was heated to 130°C, and toluene, chain transfer agent, and unreacted monomer were removed by drying to obtain a solid acrylic oligomer. The weight average molecular weight of the acrylic oligomer was 5100. The glass transition temperature (Tg) was 130°C.

After adding 0.07 parts by mass of 1,6-hexanedioldiacrylate (HDDA), 1 part by mass of an acrylic oligomer, and 0.3 parts by mass of a silane coupling agent ("KBM403" manufactured by Shin-Etsu Chemical) with respect to 100 parts by mass of the solid content of the base polymer composition, , These were mixed uniformly to prepare an adhesive composition.

An adhesive composition is applied to the surface of a release sheet containing a PET film (“Diafoil MRF75” manufactured by Mitsubishi Chemical), and then a release sheet containing another PET film (“Diafoil MRF75” manufactured by Mitsubishi Chemical) is applied to the coating film. conjoined. Thereafter, the coating film was irradiated with ultraviolet rays to prepare a pressure-sensitive adhesive sheet A having a thickness of 50 µm.

[Adhesive Sheet B]

99 parts by mass of butyl acrylate (BA) and 1 part by mass of 4-hydroxybutyl acrylate (HBA) were introduced into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet pipe, and a condenser. Thus, a monomer mixture was prepared.

Further, with respect to 100 parts by mass of the monomer mixture, 0.1 part by mass of 2,2'-azobisisobutyronitrile was introduced together with ethyl acetate, and after nitrogen gas was introduced and substituted with nitrogen gas while gently stirring, the temperature of the liquid in the flask was The polymerization reaction was carried out for 7 hours while maintaining at around 55°C. Thereafter, ethyl acetate was added to the obtained reaction solution to prepare a solution of an acrylic base polymer having a weight average molecular weight of 1,600,000 adjusted to a solid content concentration of 30%.

0.1 part by mass of an isocyanate-based crosslinking agent (trade name: Takenato D110N, trimethylolpropanxylylene diisocyanate, manufactured by Mitsui Chemicals, Inc.), benzoyl peroxide (trade name: Nyper BMT, Japan) with respect to 100 parts by mass of the solid content of the solution of the acrylic base polymer 0.3 parts by mass of oil and fat) and 0.08 parts by mass of a silane coupling agent (trade name: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) were blended to prepare an acrylic adhesive composition.

An acrylic PSA composition was uniformly coated on the surface of a release sheet made of PET film with a fountain coater and dried for 2 minutes in an air circulation type constant temperature oven at 155° C. to prepare PSA Sheet B having a thickness of 20 μm.

[Adhesive Sheet C]

99 parts by mass of butyl acrylate (BA) and 1 part by mass of 4-hydroxybutyl acrylate (HBA) were introduced into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet pipe, and a condenser.

Further, with respect to 100 parts by mass of the monomer mixture, 0.1 part by mass of 2,2'-azobisisobutyronitrile was introduced together with ethyl acetate, and after nitrogen gas was introduced and substituted with nitrogen gas while gently stirring, the temperature of the liquid in the flask was The polymerization reaction was carried out for 7 hours while maintaining at around 55°C. Thereafter, a mixed solvent of ethyl acetate and toluene (95/5 in mass ratio) was added to the obtained reaction solution to prepare an acrylic base polymer solution adjusted to a solid content concentration of 30%.

0.15 parts by mass of trimethylolpropane/tolylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name: Coronet L) and a silane coupling agent (trade name: KBM403, Shin-Etsu Chemical Industry Co., Ltd.) Preparation) 0.08 part by mass was blended to prepare an acrylic pressure-sensitive adhesive composition.

A pressure-sensitive adhesive sheet C having a thickness of 15 μm was prepared by uniformly coating the surface of a release sheet made of PET film with a fountain coater and drying for 2 minutes in an air circulation type constant temperature oven at 155° C.

[Adhesive Sheet D]

99 parts by mass of butyl acrylate (BA) and 1 part by mass of 4-hydroxybutyl acrylate (HBA) were introduced into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet pipe, and a condenser. Thus, a monomer mixture was prepared.

Further, with respect to 100 parts by mass of the monomer mixture, 0.1 part by mass of 2,2'-azobisisobutyronitrile was introduced together with ethyl acetate, and after nitrogen gas was introduced and substituted with nitrogen gas while gently stirring, the temperature of the liquid in the flask was The polymerization reaction was carried out for 7 hours while maintaining at around 55°C. Thereafter, ethyl acetate was added to the obtained reaction solution to prepare a solution of an acrylic base polymer having a weight average molecular weight of 1,600,000 adjusted to a solid content concentration of 30%.

0.1 part by mass of an isocyanate-based crosslinking agent (trade name: Takenato D110N, trimethylolpropanxylylene diisocyanate, manufactured by Mitsui Chemicals, Inc.), benzoyl peroxide (trade name: Nyper BMT, Japan) with respect to 100 parts by mass of the solid content of the solution of the acrylic base polymer 0.3 parts by mass of oil and fat) and 0.08 parts by mass of a silane coupling agent (trade name: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) were blended to prepare an acrylic adhesive composition.

An acrylic PSA composition was uniformly coated on the surface of a release sheet made of PET film with a fountain coater and dried in an air circulation constant temperature oven at 155° C. for 2 minutes to prepare PSA Sheet D with a thickness of 5 μm.

[Shear storage modulus (G') of adhesive sheet]

The shear storage modulus (G') at 25°C of each of PSA sheets A to C was measured.

Specifically, the release sheet was peeled off, externally processed into a disc shape, inserted into a parallel plate, and using the 'Advanced Rheometric Expansion System (ARES)' manufactured by Rheometric Scientific, the following conditions The shear storage modulus (G') of the pressure-sensitive adhesive sheet was determined by measuring the dynamic viscoelasticity of .

[Measuring conditions]

Mode: Torsion

Temperature: -40℃ to 150℃

Heating rate: 5°C/min

Frequency: 1Hz

[Preparation of substrate]

Substrates A to D were prepared as follows.

[Reference A]

A substrate containing COP (trade name 'Zeonoa', manufactured by Zeon Co., Ltd., Japan) was prepared as substrate A.

[Registration B]

A substrate made of PET (trade name 'Lumiror S10', manufactured by Toray) was prepared as substrate B.

[Registration C]

A substrate made of a transparent soft polyester resin (trade name 'OKY100', manufactured by Bell Polyester Products) was prepared as the substrate C.

[Registration D]

A substrate made of transparent polyimide (product name 'C_50', manufactured by KOLON) was prepared as substrate D.

[Tensile modulus of elasticity (E) of base material]

The tensile modulus (E) at 25° C. of each of substrates A to D was measured.

Each of the substrates A to D was externally processed into a rectangular shape with a width of 10 mm and a length of 100 mm. The substrate is installed in a tensile tester (manufactured by Shimadzu Corporation, product name 'Autograph AG-IS'), and strain and stress are measured when the substrate is stretched at 200 mm/min, and the strain is a curve in the range of 0.05% to 0.25%. From the slope of , the tensile modulus (E) of the substrate was calculated. The tensile elastic moduli (E) at 25°C of each of the substrates A to D were 3 GPa, 3.5 GPa, 0.13 GPa, and 7 GPa, respectively.

[Production of Similar Samples of Organic EL Display Device 1 Corresponding to First Embodiment]

Example 1

Each of the first adhesive layer 8 including the adhesive sheet A and the second adhesive layer 10 including the adhesive sheet C are applied to each of the front and back surfaces of the substrate 9 including the substrate A. placed. In this way, the shock absorbing member 3 was fabricated by sequentially including the first adhesive layer 8, the base material 9, and the second adhesive layer 10 in the thickness direction. That is, a shock absorbing member 3 composed of three layers was produced.

As shown in FIG. 1, after that, the window member 2, the impact absorbing member 3, the organic EL panel member 4, and the protective member 5 are laminated to form the organic EL display device 1. A similar sample was prepared. An ITO layer 35 was disposed on the surface of the organic EL panel member 4 as a substitute for the thin film encapsulation layer 11 . The thickness of the ITO layer 35 was 40 nm.

The window member 2 is a hard coat layer 6 having a thickness of 10 μm containing a cured body of the curable composition of Example 1 of Japanese Laid-Open Patent Publication No. 2020-064236 and 'CPI' (manufactured by KOLON). and a window film 7 having a thickness of 80 μm.

As the panel main body 12 in the dummy panel member 44, a polyimide board (trade name 'UPILEX', manufactured by Ube Kosan Co., Ltd.) having a thickness of 25 µm was prepared.

The protective member 5 is made of the same material as the adhesive sheet A, and includes a front side adhesive layer 13 having a thickness of 15 μm and a polyimide plate having a thickness of 50 μm (trade name “UPILEX” manufactured by Ube Kosan Co., Ltd.). The protective base material 14 was placed in order toward the back side.

Examples 2 to 10, Examples 27 to 29, Comparative Examples 1 to 5, Comparative Example 10, and Comparative Example 11

In the same manner as in Example 1, a prototype 40 (similar sample) of the organic EL display device 1 was manufactured. However, the first adhesive layer 8, the substrate 9 and/or the second adhesive layer 10 were changed as described in Tables 1 to 3 and Table 11.

[Production of Organic EL Display Device 1 Corresponding to Second Embodiment]

Examples 11 to 23

Processing was carried out in the same manner as in Embodiment 1 to prepare a prototype 40 (similar sample) of the organic EL display device 1. However, as shown in Fig. 9, a shock absorbing member 3 composed of five layers was used. In addition, each layer was changed as described in Tables 4 to 8. Specifically, the shock absorbing member 3 includes the first adhesive layer 8, the first substrate 25, the intermediate adhesive layer 19, the second substrate 26, and the second adhesive layer 10 in order. provide

[Production of Organic EL Display Device 1 Corresponding to Modification of Second Embodiment]

Examples 24 to 26

Processing was carried out in the same manner as in Example 1 to prepare a prototype 40 (similar sample) of the organic EL display device 1. However, as shown in Fig. 10, a shock absorbing member 3 composed of seven layers was used. In addition, each layer was changed as described in Table 9. Specifically, the shock absorbing member 3 includes the first adhesive layer 8, the first substrate 25, the first intermediate adhesive layer 27, the third substrate 29, and the second intermediate adhesive layer 28. and a second substrate 26 and a second adhesive layer 10 in order.

[Manufacture of organic EL display device 1 in which shock absorbing member 3 includes only adhesive layer 30]

Comparative Examples 6 to 9

Processing was carried out in the same manner as in Example 1 to prepare a prototype 40 (similar sample) of the organic EL display device 1. However, although not shown, a shock absorbing member 3 composed of one layer was used. The shock absorbing member 3 includes only the adhesive layer 30 . The adhesive layer 30 was changed as shown in Table 10.

[evaluation]

The following items were evaluated. Their results are shown in Tables 1 to 11.

[Ball shock absorption rate per unit thickness of shock absorbing member 3]

The shock absorbing member 3 in each Example and each Comparative Example was prepared. Subsequently, as shown in Fig. 2B, only the window member 2 was placed on the surface of the sensor (product name: 480C02) 92 manufactured by PCB Corporation installed on the surface of the stainless plate 91. In this case, the window film 7 was brought into contact with the surface of the sensor 92. A stainless steel ball weighing 10 g and having a diameter of 13 mm was dropped vertically from a height of 20 cm onto the surface of the hard coat layer 6 of the window member 2. The peak value SA1 of the impact load of only the window member 2 was measured with a hi-recorder (product name: MR8870) manufactured by Hioki Corporation connected to the sensor 92.

Next, as shown in FIG. 2A, instead of the window member 2, a laminated body of the window member 2 and the shock absorbing member 3 was placed on the surface of the sensor 92. The back surface of the shock absorbing member 3 was brought into contact with the surface of the sensor 92 . On the surface of the hard coat layer 6 of the window member 2, the above-described ball was dropped vertically from a height of 20 cm. The peak value (SB1) of the impact load of the laminate of the window member 2 and the impact absorbing member 3 was measured with the above-described high recorder.

The ball shock absorption rate of the shock absorbing member 3 was obtained using the following formula.

Ball shock absorption rate (%)={(SA1-SB1)/SA1}×100

Next, the ball impact absorption ratio was divided by the thickness of the impact absorbing member 3 to calculate the ball impact absorption ratio per unit thickness of the impact absorbing member 3.

[The pen shock absorption rate of the shock absorbing member 3 and the pen shock absorption rate per unit thickness in the shock absorbing member 3]

The shock absorbing member 3 in each Example and each Comparative Example was prepared. Subsequently, as shown in Fig. 3B, only the window member 2 was placed on the surface of the sensor (product name: 480C02) 92 manufactured by PCB Corporation installed on the surface of the stainless plate 91. In this case, the window film 7 was brought into contact with the surface of the sensor 92. A ballpoint pen (BK407 Black, an oil-based ballpoint pen manufactured by Pentel Corporation) having a weight of 7 g and a ball diameter of 0.7 mm was dropped vertically from a height of 20 cm onto the surface of the hard coat layer 6 of the window member 2. The peak value (SA2) of the impact load of only the window member 2 was measured with a hi-recorder (product name: MR8870) manufactured by Hioki Corporation connected to the sensor 92.

Next, as shown in FIG. 3A, instead of the window member 2, a laminated body of the window member 2 and the impact absorbing member 3 was placed on the surface of the sensor 92. The back surface of the shock absorbing member 3 was brought into contact with the surface of the sensor 92 . The pen described above was dropped vertically from a height of 20 cm onto the surface of the hard coat layer 6 of the window member 2. The peak value (SB2) of the impact load of the laminated body of the window member 2 and the shock absorbing member 3 was measured with the above-described high recorder.

The pen shock absorption rate of the shock absorbing member 3 was obtained using the following formula.

Pen shock absorption rate (%)={(SA2-SB2)/SA2}×100

Then, the pen shock absorption rate was divided by the thickness of the shock absorbing member 3 to calculate the pen shock absorption rate per unit thickness of the shock absorbing member 3.

[Bending test of organic EL display device 1]

(1) Bending test at a distance of 8 mm between surfaces 21

The organic EL display device 1 (similar sample) was externally processed to produce a third sample 63. As shown in Figs. 4A to 4B, a bending test was conducted in which bending and opening were repeated 200,000 times. Specifically, a durability tester (model number 'DMLHB-FS-C', manufactured by YUASA) was used. The distance between the two surfaces 21 facing the outside of the window member 2 was 8 mm.

The ratio of the resistance value of the ITO layer 35 after the bending test to the resistance value of the ITO layer 35 before the bending test was measured by a tester.

The change in the resistance value of the ITO layer 35 was evaluated as the presence or absence of damage to the thin film encapsulation layer 11 .

○: The ratio of the resistance value of the ITO layer 35 after the test to the resistance value of the ITO layer 35 after the test was less than 1.1 times before the test.

x: The ratio of the resistance value of the ITO layer 35 after the test to the resistance value of the ITO layer 35 after the test was 1.1 times or more before the test.

(2) Bending test at a distance of 6 mm between the surfaces 21

For the organic EL display device 1 rated as '○' in the above (1), a bending test similar to the above was performed so that the spacing was 6 mm.

[Total light transmittance of shock absorbing member 3]

A laminate of the shock absorbing member 3 and the window member 2 was prepared. The total light transmittance of the laminate was measured using a haze meter manufactured by Suga Test Instruments. The measurement was in accordance with JIS K7105.

From the above results, the total light transmittance of the shock absorbing member 3 was determined. If the total light transmittance of the laminate is 60% or more, it can be said that the total light transmittance of the shock absorbing member 3 is also 60% or more.

Some examples are listed in a plurality of tables for easy comparison. Example 1 was repeatedly described in Tables 1 and 2. Example 7 was described in duplicate in Table 2 and Table 11. Example 12 was described in duplicate in Tables 4 and 6. Example 13 was described in duplicate in Tables 4 and 7. Example 15 was repeatedly described in Tables 5 and 6. Example 16 was described in duplicate in Tables 5 and 7.

The shear storage modulus (G') of the first adhesive layer 8 and the shear storage modulus (G') of the second adhesive layer 10 of Examples 1 to 6 are shown in FIG. 12 .

[Verification of Examples and Comparative Examples]

As can be seen from Tables 3, 10, and 11, all of Comparative Examples 1 to 5, Comparative Example 7, Comparative Example 10, and Comparative Example 11 had a ball impact absorption per unit thickness of 0.27% / is less than μm. In Comparative Examples 1 to 5, Comparative Example 7, Comparative Example 10, and Comparative Example 11, the ball impact absorption per unit thickness was insufficient.

As can be seen from Table 10, all of Comparative Examples 6 to 9 had a pen impact absorption per unit thickness of less than 0.10%/μm. Comparative Examples 6 to 9 had insufficient pen impact absorption per unit thickness for the pen.

In Comparative Example 7, peeling occurred during bending. Comparative Example 7 has insufficient bending resistance.

On the other hand, as can be seen from Tables 1, 2, 4 to 9 and 11, Examples 1 to 29 all have ball impact absorption per unit thickness of 0.27% / μm or more, and unit thickness Per pen impact absorption is 0.10%/μm or more. Therefore, the organic EL display device 1 has excellent durability against impact with the ball 90 and impact with the pen 95 . Therefore, Examples 1 to 29 are excellent in durability against various impacts.

[Verification of each embodiment]

As can be seen from Table 1, in Examples 1 to 6, the substrate 9 is the same, but the shear storage modulus (G′) of the first adhesive layer 8 and/or the second adhesive layer 10 it fluctuates

Specifically, in Example 1, Example 2, and Example 3, the shear storage modulus (G') of the first adhesive layer 8 is 0.03 MPa, 0.08 MPa, and 0.12 MPa, respectively.

In Examples 1 to 3, the shear storage modulus (G') at 25°C of the second adhesive layer 10 is higher than the shear storage modulus (G') at 25°C of the first adhesive layer 8. High examples are Example 1 and Example 2. It can be seen that Examples 1 and 2 have excellent impact resistance per unit thickness for a ball and pen, compared to Example 3.

Among Examples 1 to 6, examples in which the shear storage modulus (G′) at 25° C. of the first adhesive layer 8 is 0.05 MPa or less are Examples 1, 4, and 5. . It can be seen that Example 1, Example 4, and Example 5 are superior to Example 2, Example 3, and Example 6 in impact resistance per unit thickness for the ball.

Among Examples 1 to 6, examples in which the shear storage modulus (G′) at 25° C. of the second adhesive layer 10 is 0.10 MPa or more are Examples 1 to 3. It can be seen that Examples 1 to 3 are superior in bending resistance to Examples 4 to 6.

In Examples 1 to 6, from the shear storage modulus (G') of the second adhesive layer (10) at 25°C, the shear storage modulus (G') of the first adhesive layer (8) at 25°C (G'). ) is 0.06 MPa or more, Example 1. It can be seen that Example 1 can reliably achieve both high impact resistance per unit thickness for a ball and high impact resistance per unit thickness for a pen compared to Examples 2 to 6.

As can be seen from Table 2, among Examples 1 and 7 through 9, the ratio of the thickness of the base material 9 to the thickness of the shock absorbing member 3 is 0.20 or more and 0.35 or less. are Example 1 and Example 8. It can be seen that Examples 1 and 8 are superior to Example 7 in which the ratio exceeds 0.35, and the impact absorption per unit thickness for the ball is excellent. It can be seen that Examples 1 and 8 are superior in impact resistance per unit thickness to the pen, compared to Example 9 in which the ratio is less than 0.20. These tendencies are also the same in Examples 12, 13, and Examples 15 to 26 in which the base material 9 is plural.

That is, as can be seen from Table 6, Example 12, Example 15, and Example 18 having the above ratio of the thickness of the base material 9 have a unit thickness compared to Example 17 having the ratio exceeding 0.35. It turns out that per ball impact absorption rate is high.

As can be seen from Table 7, Example 13, Example 16 and Example 20 having the above ratio of the thickness of the substrate 9 are balls per unit thickness compared to Example 19 having the ratio exceeding 0.35. It can be seen that the shock absorption rate is high.

As can be seen from Table 8, Examples 21 and 22 having the above ratio of the thickness of the substrate 9 have higher ball impact absorption per unit thickness than Example 23 in which the ratio exceeds 0.35. can know that

Also, as can be seen from Table 9, Examples 24 and 25 having the above ratio of the thickness of the base material 9 have a ball impact absorption rate per unit thickness compared to Example 26 in which the ratio exceeds 0.35. It can be seen that this high

Also, as can be seen from Table 2, Example 1 and Example 10 differ only in the material of the substrate 9. It can be seen that Example 1 in which the material of the substrate 9 is COP has higher ball impact absorption per unit thickness than Example 10 in which the material of the substrate 9 is PET.

As can be seen from Table 11, Example 7, Example 29, and Comparative Example 11 differ only in the material of the substrate 9. Example 7 in which the material of the substrate 9 is COP and Example 29 in which the material of the substrate 9 is a polyester resin are compared to Comparative Example 11 in which the material of the substrate 9 is a polyimide resin, per unit thickness. It can be seen that the ball shock absorption rate is high.

Further, as can be seen from Table 4, in Examples 11 to 13, the shear storage modulus (G') at 25°C of the middle adhesive layer 19 was higher than that of the first adhesive layer 8 at 25°C. Example 11 is an example that is higher than the shear storage modulus (G′) at and lower than the shear storage modulus (G′) of the second adhesive layer 10 at 25° C. Example 11, compared to Examples 12 and 13, can achieve both high impact resistance and high bending resistance per unit thickness with respect to the ball.

Further, as can be seen from Table 5, in Examples 14 to 16, the shear storage modulus (G') at 25°C of the middle adhesive layer 19 was higher than that of the first adhesive layer 8 at 25°C. Example 14 is an example that is higher than the shear storage modulus (G′) at and lower than the shear storage modulus (G′) of the second adhesive layer 10 at 25° C. Example 14, compared to Examples 15 and 16, can achieve both high impact resistance per unit thickness for a ball and high bending resistance.

As can be seen from Table 4, among Examples 11 to 13, the examples in which the shear storage modulus (G′) at 25° C. of the middle adhesive layer 19 is more than 0.05 MPa and less than or equal to 0.15 MPa are examples. 11 and Example 13. Compared with Example 12, Examples 11 and 13 can achieve both high impact resistance per unit thickness for a ball, high impact resistance per unit thickness for a pen, and high bending resistance.

In addition, as can be seen from Table 5, among Examples 14 to 16, the shear storage modulus (G ') at 25 ° C. of the middle adhesive layer 19 is more than 0.05 MPa and less than 0.15 MPa Examples, Example 14 and Example 16. Compared with Example 15, Examples 14 and 16 can simultaneously achieve high impact resistance per unit thickness for a ball, high impact resistance per unit thickness for a pen, and high bending resistance.

As can be seen from Table 8, among Examples 21 and 22, Example 22 is an example in which the first substrate 25 is thicker than the second substrate 26. Example 22, compared to Example 21, can achieve both high impact resistance and high bending resistance per unit thickness with respect to the ball.

As can be seen from Table 8, among Examples 21 and 22, Example 21 is an example in which the first substrate 25 is thinner than the second substrate 26. It can be seen that Example 21 has a higher pen impact absorption per unit thickness than Example 22.

As can be seen from Table 9, among Examples 24 and 25, Example 25 is an example in which the first substrate 25 is thinner than the second substrate 26. Example 25, compared to Example 24, can achieve both high impact resistance and high bending resistance per unit thickness with respect to the ball.

As can be seen from Table 11, the tensile elastic moduli (E) of the substrates 9 of Example 7, Example 29, and Comparative Example 11 were 3 GPa, 0.13 GPa, and 7 GPa, respectively. The tensile elastic modulus (E) of the substrate 9 of Comparative Example 11 was excessively high at 7 GPa. Therefore, Example 1 and Example 29 are superior in ball impact absorption per unit thickness compared to Comparative Example 11.

In addition, the materials of the base material 9 of Example 1, Example 29, and Comparative Example 11 are COP, polyester resin, and polyimide resin, respectively. Example 1 in which the material of the substrate 9 is COP and Example 29 in which the material of the substrate 9 is a polyester resin are compared to Comparative Example 11 in which the material of the substrate 9 is a polyimide resin, per unit thickness. Excellent ball shock absorption.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

[Table 10]

[Table 11]

In addition, although the said invention was provided as embodiment of an illustration of this invention, this is only an illustration and should not be interpreted limitedly. Modifications of the present invention obvious to those skilled in the art are included in the following claims.

An image display member is used as an organic electroluminescent display device, for example.

1: organic EL display device
2: No window
3: shock absorbing member
4: organic EL panel member
5: protective member
8: first adhesive layer
9: registration
10: second adhesive layer
19: middle adhesive layer
21: surface
22: back side
25: first substrate
26: second substrate
29: third article
90: ball
95: pen
96: ball (tip end of pen)
S1: 1st process
S2: Second process
S3: 3rd process
S4: 4th process
S5: 5th process
S6: 6th process
S7: 7th process

Claims (20)

An image display device comprising a window member, a shock absorbing member, a panel member, and a protective member in order on one side in the thickness direction, comprising:
The shock absorbing member has a total light transmittance of 60% or more,
The unit thickness of the shock absorbing member obtained by dividing the ball shock absorption rate of the shock absorbing member obtained by dropping a stainless steel ball weighing 10 g and having a diameter of 13 mm from a height of 20 cm onto the shock absorbing member by the thickness of the shock absorbing member Per ball impact absorption is 0.27% / μm or more,
The unit of the shock absorbing member obtained by dividing the pen shock absorption rate of the shock absorbing member obtained by dropping a ballpoint pen having a weight of 7 g and a ball diameter of 0.7 mm at the tip from a height of 20 cm onto the shock absorbing member by the thickness of the shock absorbing member An image display device having a pen impact absorption rate per thickness of 0.10%/μm or more. According to claim 1,
In a test in which the image display device is bent so that the window member faces outward,
The image display device, wherein the panel member is not damaged even when the window member is bent 200,000 times so that the distance between the two surfaces facing outward is 8 mm. According to claim 1 or 2,
The image display device, wherein the shock absorbing member includes a first adhesive layer, a base material, and a second adhesive layer in order toward one side in the thickness direction. According to claim 3,
The first adhesive layer contacts the window member,
The second adhesive layer is in contact with the panel member, the image display device. According to claim 3 or 4,
The shear storage modulus (G') of the second adhesive layer at 25°C is equal to or higher than the shear storage modulus (G') of the first adhesive layer at 25°C. According to any one of claims 3 to 5,
The image display device, wherein the first adhesive layer has a shear storage modulus (G') at 25°C of 0.01 MPa or more and 0.05 MPa or less. According to any one of claims 3 to 6,
The image display device, wherein the second adhesive layer has a shear storage modulus (G') at 25°C of 0.10 MPa or more and 0.15 MPa or less. According to any one of claims 3 to 7,
The value obtained by subtracting the shear storage modulus (G') at 25°C of the first adhesive layer from the shear storage modulus (G') of the second adhesive layer at 25°C is 0.06 MPa or more. According to any one of claims 3 to 8,
The image display device in which the said description is singular. According to any one of claims 3 to 8,
The above description is plural,
An image display device further comprising an intermediate adhesive layer disposed between a plurality of the substrates. According to claim 10,
The shear storage modulus (G') of the middle adhesive layer at 25°C is equal to or greater than the shear storage modulus (G') of the first adhesive layer at 25°C, and the shear storage modulus of the second adhesive layer at 25°C. (G') or less, an image display device. According to claim 10 or 11,
The shear storage modulus (G′) of the middle adhesive layer at 25° C. is higher than the shear storage modulus (G′) of the first adhesive layer at 25° C., and the shear storage modulus of the second adhesive layer at 25° C. (G') Lower, image display device. According to any one of claims 10 to 12,
The shear storage modulus (G') at 25°C of the middle adhesive layer is greater than 0.05 MPa and less than or equal to 0.15 MPa. According to any one of claims 10 to 13,
The above description
A first substrate in contact with the first adhesive layer;
Including a second substrate in contact with the second adhesive layer,
The image display device in which the said 1st base material is thinner than the said 2nd base material. According to any one of claims 10 to 13,
The above description
A first substrate in contact with the first adhesive layer;
Including a second substrate in contact with the second adhesive layer,
The image display device in which the said 1st base material is thicker than the said 2nd base material. According to any one of claims 3 to 15,
The image display device, wherein the ratio of the thickness of the base material to the thickness of the shock absorbing member is 0.20 or more and 0.35 or less. According to any one of claims 3 to 16,
The image display device in which the material of the said base material is an olefin resin and/or a polyester resin. According to claim 17,
The image display device in which the said olefin resin is a cycloolefin resin. According to claim 17,
An image display device in which the polyester resin is polyethylene terephthalate. A method for manufacturing an image display device comprising a window member, a first adhesive layer, a base material, a second adhesive layer, a panel member, and a protective member in order on one side in the thickness direction,
A first step of starting a trial product;
A second step of evaluating the prototype;
A third step of determining manufacturing conditions based on the evaluation;
A fourth step of manufacturing a product based on the manufacturing conditions,
The second process,
A fifth step of producing a first sample and a second sample from the prototype;
A sixth step of dropping a ball on the first sample and dropping a ballpoint pen on the second sample;
After the sixth step, a seventh step of determining whether or not there is damage to the first sample and the second sample is provided,
In the third process, when the prototype is evaluated as having damage to the first sample, the manufacturing conditions are changed so that the total thickness of the first adhesive layer and the second adhesive layer is thicker, and the second The manufacturing method of the image display apparatus which changes the thickness of the said base material so that it may become thicker, when the prototype is evaluated that there is damage to a sample.

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