KR102562977B1 - Electro-optical Panel - Google Patents

Abstract

An object of the present invention is to provide a flexible electro-optical panel that is easily restored to its original planar state even when left in a deformed state for a long time or repeatedly deformed.
An electro-optical panel according to the present invention is a flexible electro-optical panel comprising an electro-optical element that emits light or controls the transmission of light, and two films formed of a polymer material, wherein the two films have an in-plane anisotropy of elastic modulus , and the direction having the maximum modulus of elasticity of each film is different for the thickness direction of the electro-optical panel.

Description

Electro-optical panel {Electro-optical panel}

The present invention relates to an electro-optical panel including a display panel and a lighting panel.

Electro-optical panels such as OLED (organic light-emitting diode) display panels, OLED lighting panels, cholesteric liquid crystal display panels, PDLC (polymer dispersed liquid crystal) display panels, and electrophoretic display panels are electro-optical elements (e.g., light emitting element and liquid crystal element), and has a plurality of layers (for example, Patent Document 1). In the present specification, the term 'electro-optical element' includes a light emitting element (eg OLED element) emitting light by electrical action and a light control element (eg liquid crystal element) controlling transmission of light by electric action. And, 'electro-optical panel' refers to a panel having such an electro-optical element.

In recent years, flexible panels and lighting panels have been developed, and these flexible electro-optic panels have a plurality of laminated films, and at least some of the films are formed from a polymer material (eg, resin).

Patent Document 1: Japanese Patent Laid-Open No. 2015-152922

Flexible electro-optical panels include a bendable panel that can be bent, a rollable panel that can be rounded, and a foldable panel that can be folded. They are maintained in a deformed state for a long time, that is, when left unattended or repeatedly deformed, deformation (ie, curl or bending) remains, and it is difficult to return to the original planar state even if they are tried to redeploy to a flat state.

Accordingly, an object of the present invention is to provide a flexible electro-optical panel that is easily restored to its original planar state even when left in a deformed state for a long time or repeatedly deformed.

In order to solve the above problems and achieve the object, an electro-optical panel according to the present invention is a flexible electro-optical panel comprising an electro-optical element that emits light or controls the transmission of light and two films formed of a polymer material. The panel is characterized in that the two films have in-plane anisotropy of elastic modulus, and the directions having the maximum elastic modulus of each film are different in the thickness direction of the electro-optical panel.

In addition, in one embodiment of the present invention, it is characterized in that the directions having the maximum modulus of elasticity of the two films are 90 degrees different from each other.

Further, in one embodiment of the present invention, the electro-optical panel is rectangular, and the direction of the maximum modulus of elasticity of the two films coincides with the direction of the side of the electro-optical panel.

In one embodiment of the present invention, the two films are disposed on both sides of the electro-optical element.

Also, in one embodiment of the present invention, the two films are characterized in that they are uniaxially stretched films, biaxially stretched films or cast films.

Further, in one embodiment of the present invention, the above two films are characterized in that they are disposed on the light emitting side.

In one embodiment of the present invention, the two films are cast films.

Further, in one embodiment of the present invention, a pressure-sensitive adhesive is further disposed between the two films.

Further, the electro-optical panel according to the present invention is a flexible electro-optical panel equipped with an electro-optical element that emits light or controls the transmission of light, and a film formed of a polymer material, wherein the film has an in-plane anisotropy of elastic modulus It is characterized in that it has two different layers, and the direction having the maximum modulus of elasticity of each layer is different from each other with respect to the thickness direction of the electro-optical panel.

Further, in one embodiment of the present invention, it is characterized in that the directions having the maximum modulus of elasticity of the two layers are 90 degrees different from each other.

Further, in one embodiment of the present invention, the electro-optical panel is rectangular, and the direction of the maximum modulus of elasticity of the two layers coincides with the direction of the side of the electro-optical panel.

Further, in one embodiment of the present invention, the film is characterized in that it is disposed on the light emitting side.

In one embodiment of the present invention, the film is a cast film.

In one embodiment of the present invention, a layer having an in-plane anisotropy of elastic modulus different from that of the above two layers is further included between the above two layers.

According to the present invention, since the two films constituting the electro-optical panel are disposed in different directions having the maximum in-plane modulus of elasticity, or two layers having the maximum in-plane modulus of elasticity in different directions are formed. Therefore, even if the electro-optical panel is deformed in a plurality of directions and stored for a long time, or the electro-optical panel is repeatedly deformed in a plurality of directions, the force to return the film to its original shape acts and deforms (ie, curls or warps). Since this does not remain, it has the effect of being able to return to the original planar state by redeployment in a planar state.

1 is a schematic cross-sectional view of an OLED display panel according to a first embodiment.
Fig. 2 is a diagram showing the direction of the maximum in-plane modulus of elasticity of the front film and the back film in the OLED display panel.
3 is a perspective view in which the OLED display panel is disassembled for each component.
FIG. 4 is a side view schematically illustrating a state in which the OLED display panel of FIG. 1 is rounded.
FIG. 5 is a side view schematically illustrating a bent state of the OLED display panel of FIG. 1 .
6 is a side view schematically illustrating a state when a general OLED display panel is to be re-deployed into a flat state after being maintained in a deformed state for a long time.
Fig. 7 is a side view of the OLED display panel showing the experimental method according to the first embodiment.
8 is a diagram explaining a method for measuring the amount of residual strain in the above experiment.
Fig. 9 is a side view of the OLED display panel showing another experimental method according to the first embodiment.
Fig. 10 is a table showing details of samples used in this experiment.
Fig. 11 is a cross-sectional view schematically showing the structure of a sample used in this experiment.
Fig. 12 is a cross-sectional view schematically showing the structure of a sample used in this experiment.
13 is a graph showing the experimental results of FIGS. 7 and 9 .
14 is a schematic cross-sectional view of an OLED display panel according to a second embodiment.
15 is a diagram showing the direction of the maximum in-plane modulus of elasticity of the front film in the OLED display panel.
16 is a perspective view in which the OLED display panel is disassembled for each component.
17 is a schematic cross-sectional view of an OLED display panel according to a third embodiment.
18 is a diagram showing the direction of the maximum in-plane modulus of elasticity of the front film in the OLED display panel.
19 is a schematic cross-sectional view of an OLED display panel according to a first modified example.
20 is a schematic cross-sectional view of an OLED display panel according to a second modified example.
21 is a schematic cross-sectional view of an OLED display panel according to a second modified example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, with reference to the drawings, a mode for implementing the electro-optical panel according to the present invention will be described based on the drawings.

Objects, advantages and novel features of the present invention will become more apparent from the following detailed description in conjunction with the drawings. In different figures, the same reference numbers are used to show the same or functionally similar elements. It should be understood that the drawings are schematic and are not to scale.

<First Embodiment>

The first embodiment will be described with reference to the drawings. 1 is a schematic cross-sectional view of an OLED display panel 1 according to a first embodiment. The OLED display panel 1 is a top emission type that emits light generated in the OLED layer 13 toward the opposite side of the flexible substrate 10 (ie, upward in the drawing). Arrows in the drawing indicate the emission direction of light.

As shown in FIG. 1 , the OLED display panel 1 has a flexible substrate (flexible film) 10 and a barrier layer (barrier film) 11 formed thereon. The flexible substrate 10 is formed from a polymer material, for example polyimide. The barrier layer 11 is formed from a polymer material or an inorganic material. In this embodiment, the OLED display panel 1 is rectangular.

On the barrier layer 11, a thin film transistor (TFT) layer 12, an OLED layer 13, and a color filter layer 14 are formed. Although not shown in detail, the TFT layer 12 has a number of TFT layers and an interlayer insulating film covering the TFTs. The OLED layer 13 has layers such as an anode, a cathode, and a light emitting layer. The color filter layer 14 has not only color filters, but also an interlayer insulating film and wiring connecting the electrodes of the TFT and OLED layer 13 through the interlayer insulating film. For the color filter layer 14, an RGB type or RGBW type is used.

The TFT layer 12, the OLED layer 13, and the color filter layer 14 are covered with a passivation layer 15. The passivation layer 15 is formed of, for example, SiO ₂ . Furthermore, the passivation layer 15 is covered with the capsule encapsulation body 16 . The capsule encapsulation body 16 is made of, for example, an epoxy resin. The passivation layer 15 and the encapsulation body 16 cover and protect the TFT layer 12, the OLED layer 13, and the color filter layer 14.

On the capsule encapsulation body 16, a circular polarizing plate 17 is formed. The circular polarizing plate 17 reduces external light reflection. The circularly polarizing plate 17 is composed of a retardation film and a polarizing film disposed on the light emitting side (above the retardation film) of the retardation film. The circularly polarizing plate 17 is a stretched film formed from a polymer material. Even when the circular polarizing plate 17 is attached to the capsule encapsulation body 16 through an adhesive (not shown), the covalent bonding action between the material of the circular polarizing plate 17 and the capsule encapsulating body 16 or the covalent bond and intermolecular force may be directly bonded by the cooperative action of As the adhesive, a pressure sensitive adhesive (PSA) is used, for example.

Further, the retardation film and the polarizing film may be bonded via an adhesive or may be directly bonded by a covalent bonding action between the retardation film material and the polarizing film material or a cooperative action of covalent bonding and intermolecular forces. As the adhesive, a pressure-sensitive adhesive is used, for example.

A touch panel 18 is formed on the circular polarizing plate 17 . The touch panel 18 is attached to the circular polarizing plate 17 through, for example, an adhesive (not shown). As the adhesive, a pressure-sensitive adhesive is used, for example. In addition, when the touch panel function is unnecessary for the OLED display panel 1, the touch panel 18 is not required.

A front film 20 is bonded to the touch panel 18 via an adhesive layer 19 .

As the adhesive layer 19, a pressure sensitive adhesive is used. However, excluding the adhesive layer 19, the front film 20 is applied to the touch panel 18, the covalent bonding action of the front film 20 material and the touch panel 18 material, or the cooperative action of the covalent bonding and intermolecular forces. may be directly joined by

The front film 20 improves the strength of the OLED display panel 1 . The front film 20 is formed from a polymer material such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate) or PI (polyimide). In addition, the structure of the front film 20 will be described in detail later.

A hard coat 21 is formed on the front film 20 . The hard coat 21 is provided to suppress surface defects. The hard coat 21 is made of, for example, an acrylic resin.

In addition, a backing film 23 is bonded under the flexible substrate 10 via an adhesive layer 22 .

As the adhesive layer 22, a pressure sensitive adhesive is used. However, excluding the adhesive layer 22, the backing film 23 to the flexible substrate 10, the covalent bonding action of the backing film 23 material and the flexible substrate 10 material or the cooperative action of covalent bonding and intermolecular forces may be directly joined by

The backing film 23 improves the strength of the OLED display panel 1 . The backing film 23 is formed from a polymer material such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate) or PI (polyimide). Excluding the adhesive layer 22, the backing film 23 is attached to the flexible substrate 10 by the covalent bonding action of the backing film 23 material and the flexible substrate 10 material or the cooperative action of covalent bonding and intermolecular forces. You can connect directly.

<Structure of front film and back film>

Next, the structures of the front film 20 and the back film 23 will be described. FIG. 2 is a diagram showing the direction of the maximum in-plane modulus of elasticity of the front film 20 and the back film 23 in the OLED display panel 1 . Here, the modulus of elasticity is a physical property value representing the difficulty of deformation, and is a general term for proportional constants between stress and strain in elastic deformation. Therefore, the direction of the maximum in-plane elastic modulus means the direction in which deformation is most difficult among the in-plane directions of the front film 20 and the back film 23 .

In the OLED display panel 1 of the present application, films having in-plane anisotropy of elastic modulus are used for the front film 20 and the back film 23 . Since in-plane anisotropy of elastic modulus occurs when the polymer chains are oriented to a certain extent, as a film having in-plane anisotropy of elastic modulus, for example, a uniaxially stretched film, a biaxially stretched film, and a cast film can be used. Further, the PET film, PEN film and PI film can be produced by a stretched film method and a cast method.

In the figure, the maximum elastic modulus of the front film 20 increased in the direction of the arrow, that is, in a direction parallel to the figure. On the other hand, the maximum elastic modulus of the rear film 23 increased in the direction of the arrow, that is, in the direction orthogonal to the drawing. Therefore, the direction having the maximum in-plane modulus of elasticity of the front film 20 and the direction having the maximum in-plane modulus of elasticity of the backing film 23 are 90 degrees different.

3 is a perspective view in which the OLED display panel 1 is disassembled for each component. The direction having the maximum in-plane modulus of elasticity of the front film 20 is in the X direction (long side direction), and the direction having the maximum in-plane modulus of elasticity of the back film 23 is in the Y direction (short side direction), and is 90 degrees different from each other. The reason why the direction having the maximum in-plane modulus of elasticity of the front film 20 and the direction having the maximum in-plane modulus of elasticity of the back film 23 are arranged 90 degrees apart, as in the OLED display panel 1 of the present application, will be explained.

4 is a side view schematically showing the OLED display panel 1 in a rounded state, and FIG. 5 is a side view schematically showing the OLED display panel 1 in a bent state. Flexible electro-optical panels include a bendable panel that can be bent, a rollable panel that can be rounded, and a foldable panel that can be folded. The OLED display panel 1 may be any of a bendable panel, a rollable panel, and a foldable panel. In either case, when the OLED display panel is kept in a deformed state for a long time or repeatedly deformed, deformation (ie, curl or warp) remains, and it is difficult to return to the original planar state even when trying to unfold it again.

4 and 5, it is assumed that the front film 20 is turned inside, that is, the case where the light emitting side of the electro-optic panel is bent or rounded is turned inside, but the back film 23 is turned inside , that is, the case where the light emitting side of the electro-optical panel is turned to the outside and bent or rounded is the same.

FIG. 6 is a side view schematically showing a state when an ordinary OLED display panel 24 is maintained in a deformed state for a long time and then re-deployed to a flat state. The left side of FIG. 6 shows the state of the OLED display panel 24 after long-term deformation by bending or rounding in the long side direction, and the right side of FIG. 6 shows the OLED display panel 24 after long-term deformation by bending or rounding in the short side direction. The state of (24) is shown. In either case, the original planar state does not completely return, and deformation (ie, curl or warp) remains.

In contrast, even if the OLED display panel 1 of the present application is deformed or repeatedly deformed for a long time by bending or rounding at an angle with respect to the long side direction (short side direction), the direction having the maximum in-plane modulus of elasticity of the front film 20 and , Since the direction having the maximum in-plane modulus of elasticity of the backing film 23 is disposed differently by 90 degrees, the force to return to the original shape of the front film 20 and the backing film 23 acts, and deformation (ie, curl or bending) ) does not remain and can return to the original planar state by redeployment to a planar state.

Furthermore, even if the OLED display panel 1 of the present application is deformed or repeatedly deformed for a long time by bending or rounding it in the long side direction, since the direction having the maximum in-plane elastic modulus of the front film 20 is in the long side direction, the front film 20 When the force to return to its original shape acts and deformation (ie, curl or bending) does not remain, and it is redeployed to a flat state, it can return to its original planar state.

Similarly, even if the OLED display panel 1 of the present application is deformed or repeatedly deformed by bending or rounding it in the direction of the short side, since the direction having the maximum in-plane elastic modulus of the backing film 23 is in the direction of the short side, the backing film 23 When a force to return to the original shape is applied and deformation (ie, curl or bending) does not remain, and it is redeployed to a flat state, it can return to the original flat state.

Several experiments were conducted to confirm the above effect. Fig. 7 is a side view of the OLED display panel showing the experimental method according to the first embodiment. In one experimental method, as shown in FIG. 7, a sample 27 in a bent state is sandwiched between two parallel glass plates 25 and 26 spaced apart by 4 mm, and then held at a temperature of 60° C. for 24 hours. neglected Then, deformation remained in the sample 27. Fig. 8 is a diagram explaining a method for measuring the amount of residual strain in the above experiment. The length (or width, L ₁ ) of the sample 27 in the deformed state was shorter than the length (or width, L) of the sample 27 in the initial planar state. And the residual strain (R) was calculated according to Equation (1).

R = (L - L ₁ ) / L ------------ (1)

Fig. 9 is a side view of the OLED display panel showing another experimental method according to the first embodiment. In another experiment, as shown in Fig. 9, a sample 27 was wound around a rigid cylinder 28 having a diameter of 60 mm and left at a temperature of 60 DEG C for 24 hours. Again, deformation remained in sample 27. The residual strain (R) was calculated according to equation (1).

Fig. 10 is a table showing details of samples 27 (A and B) used in this experiment. Fig. 11 is a cross-sectional view schematically showing the structure of a sample (A) used in this experiment. Fig. 12 is a cross-sectional view schematically showing the structure of a sample (B) used in this experiment. As shown in the figure, both samples A and B have a three-layer structure in which two PET composition films 29 and 30 are bonded together with a pressure-sensitive adhesive 31. The size of samples (A and B) is 10 cm x 10 cm.

For the two PET composition films 29 and 30, A4300 manufactured by TOYOBO CO., LTD. was used. This film is a stretched film composed only of a PET composition, and has a thickness of 50 μm. A PET composition is a composition containing polyethylene terephthalate as a main component and other additives.

In Sample A, the directions having the maximum in-plane modulus of elasticity of the two PET composition films 29 and 30 are orthogonal, that is, 90 degrees different. On the other hand, in sample B, the directions having the maximum in-plane modulus of elasticity of the two PET composition films 29 and 30 are parallel, that is, the same.

Here, the direction measurement of the maximum in-plane elastic modulus was performed as follows. For the in-plane modulus of elasticity of the film, a tensile test was performed based on the method described in ASTM-D-822, and the tensile modulus was determined. In order to investigate the direction of the maximum elastic modulus of the film, the MD direction of the film (the resin flow direction of the film formation line) is set at an angle of 0 degrees, and the clockwise angles of 0 degrees, 30 degrees, 60 degrees, 90 degrees, 120 degrees, and 150 degrees are , the films were cut into elongated shapes, respectively, so as to coincide with the direction of the long side. A tensile test was performed in the direction of the long side, and the tensile elastic modulus was calculated for each angle to determine the direction in which the maximum elastic modulus was obtained.

As a result of measuring the tensile elastic modulus at each angle, the direction of the maximum elastic modulus was 4.9 GPa at 60 degrees. Also, the direction of the minimum elastic modulus was 4.3 GPa at 150 degrees. It was found that the direction of the maximum elastic modulus does not necessarily coincide with the MD direction or the TD direction perpendicular to the MD direction. Based on the measurement results, the two PET composition films were properly oriented and bonded with a pressure-sensitive adhesive, and then cut into 10 cm x 10 cm size. In addition, the angle interval is not limited to 30 degrees, and the direction of the maximum elastic modulus can be obtained more accurately by using a smaller angular interval, such as 5 degrees or 10 degrees, or by using the least square method.

As the pressure-sensitive adhesive 31, DIC Corporation's DAITAC ZB7011W-2 (film thickness: 25 μm) was used, but other commercial products may be used.

13 is a table showing the experimental results of FIGS. 7 and 9 . In the figure, a portion having a radius of curvature of 2 mm shows the experimental results of FIG. 7 , and a portion having a radius of curvature of 30 mm shows the experimental results of FIG. 9 .

Note that the bending direction in the x direction indicates that samples A and B were bent in the x direction. Therefore, sample A shows that it was bent in the same direction as the direction of the maximum modulus of elasticity of the PET composition film 29 and in a direction orthogonal to the direction of the maximum modulus of elasticity of the PET composition film 30 . In addition, sample B shows that it is bent in the same direction as the direction of the maximum elastic modulus of the PET composition film 29 and the direction of the maximum elastic modulus of the PET composition film 30 . In this experiment, samples A and B were bent with the PET composition film 29 on the inside and the PET composition film 30 on the outside.

In addition, that the bending direction is the y-direction indicates that samples A and B were bent in the y-direction. Therefore, sample A shows that it was bent in the direction orthogonal to the direction of the maximum modulus of elasticity of the PET composition film 29 and also in the same direction as the direction of the maximum modulus of elasticity of the PET composition film 30 . Sample B is bent in a direction orthogonal to the direction of the maximum modulus of elasticity of the PET composition film 29 and the direction of the maximum modulus of elasticity of the PET composition film 30 . In this experiment, samples A and B were bent with the PET composition film 29 on the inside and the PET composition film 30 on the outside.

As is clear from Fig. 13, the average value of the residual strain (R) when sample A is bent in the x direction and when bent in the y direction is the residual strain (R) when sample B is bent in the x direction and in the y direction. ) was smaller than the average value of

The modulus of elasticity is an index indicating the difficulty of deformation, and when there is an anisotropy of the modulus of elasticity in the film plane, the direction in which the modulus of elasticity is the highest is the most difficult to deform with respect to stress. In sample A, the direction of the maximum elastic modulus of either the inner film or the outer film is the same for the bending direction x and the bending direction y. On the other hand, in the sample B, in the bending direction x, the direction of the maximum elastic modulus of both the inner film and the outer film is the same and is the most difficult to deform. However, in the bending direction y, the direction of the lowest elastic modulus of both the inner film and the outer film is the same and is most easily deformed.

From this experiment, it was found that sample A was preferred when bending in multiple directions. Like the sample used in this experiment, when the OLED display panel has a square shape, it is difficult to distinguish between the x direction and the y direction, so it is difficult to always bend it only in the x direction or only in the y direction. In this case, it was found that the composition of sample A was particularly good.

In this embodiment, the direction having the maximum in-plane modulus of elasticity of the front film 20 is in the long side direction, and the direction having the maximum in-plane modulus of elasticity of the backing film 23 is in the direction of the short side, but the maximum in-plane modulus of elasticity of the front film 20 is in the direction of the short side. It is in this short side direction, and the maximum in-plane elastic modulus of the backing film 23 may exist in the long side direction.

Further, in the present embodiment, the direction having the maximum in-plane modulus of elasticity of the front film 20 is in the long side direction, and the direction having the maximum in-plane modulus of elasticity of the back film 23 is in the direction of the short side and is 90 degrees different from each other, but 90 degrees different from each other. The direction having the maximum in-plane modulus of elasticity of the front surface film 20 and the direction having the maximum in-plane modulus of elasticity of the backing film 23 do not have to coincide with the direction of the long side and the direction of the short side of the OLED display panel 1 .

Furthermore, even if the direction having the maximum in-plane modulus of elasticity of the front film 20 and the direction having the maximum in-plane modulus of elasticity of the back film 23 do not differ by up to 90 degrees, the same effect can be obtained even if they differ by an angle smaller than 90 degrees, for example, 30 degrees. have

According to the first embodiment, since the front film and the back film constituting the OLED display panel are disposed in different directions having the maximum in-plane elastic modulus, even if the OLED display panel is deformed in a plurality of directions and stored for a long time, or the OLED display panel Even if it is repeatedly deformed in multiple directions, the force to return to the original shape of the front film or the back film acts, and no deformation (ie, curl or warp) remains. .

<Second Embodiment>

Next, a second embodiment of the electro-optical panel according to the present invention will be described. In the second embodiment to be described below, the same reference numerals are assigned to components common to those of the first embodiment, and descriptions thereof are omitted. In the first embodiment, the direction having the maximum in-plane modulus of elasticity in the front film and the direction having the maximum in-plane modulus of elasticity in the back film are arranged differently, but in the second embodiment, the front film has a two-layer structure , and the directions having the maximum in-plane modulus of elasticity in the front film are arranged differently.

14 is a cross-sectional view schematically showing an OLED display panel 41 according to the second embodiment. As shown in FIG. 14, the OLED display panel 41 includes a flexible substrate (flexible film 10), a barrier layer (barrier film 11), a TFT layer 12, an OLED layer 13, and a color filter layer 14. , Passivation layer 15, capsule encapsulation 16, circular polarizing plate 17, touch panel 18, adhesive layer 19, front film 42, adhesive layer 43, front film 44, A hard coat 21, an adhesive layer 22, and a backing film 45 are provided. In this embodiment, the OLED display panel 41 is rectangular.

The OLED display panel 41 has a flexible substrate (flexible film) 10 and a barrier layer (barrier film) 11 formed thereon. On the barrier layer 11, a thin film transistor (TFT) layer 12, an OLED layer 13, and a color filter layer 14 are formed. The TFT layer 12, the OLED layer 13, and the color filter layer 14 are covered with a passivation layer 15. Furthermore, the passivation layer 15 is covered with the capsule sealing body 16 . On the capsule encapsulation body 16, a circular polarizing plate 17 is formed. A touch panel 18 is formed on the circular polarizing plate 17 .

A front film 42 is bonded to the touch panel 18 via an adhesive layer 19 . Furthermore, a front film 44 is attached to the front film 42 via an adhesive layer 43 .

The front films 42 and 44 improve the strength of the OLED display panel 41 . The front films 42 and 44 are formed from a high molecular material such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate) or PI (polyimide). As the adhesive layer 43, a pressure sensitive adhesive is used. In addition, the structures of the front films 42 and 44 will be described in detail later.

A hard coat 21 is formed on the front film 44 . In addition, a back film 45 is attached to the bottom of the flexible substrate 10 via an adhesive layer 22 .

The back film 45 improves the strength of the OLED display panel 41 . The back film 45 is formed from a high molecular material such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate) or PI (polyimide). Excluding the adhesive layer 22, the backing film 45 is applied to the flexible substrate 10 by the covalent bonding action of the backing film 45 material and the flexible substrate 10 material or the cooperative action of covalent bonding and intermolecular forces. You can connect directly.

In the backing film 45, unlike the backing film 23 described in the first embodiment, it is not necessary to consider the direction of the maximum in-plane elastic modulus.

<Structure of front film>

Next, the structures of the front films 42 and 44 will be described. 15 is a diagram showing the direction of the maximum in-plane modulus of elasticity of the front films 42 and 44 in the OLED display panel 41 .

In the OLED display panel 41 of the present application, films having in-plane anisotropy of elastic modulus are used for the front films 42 and 44 . As the film having in-plane anisotropy of elastic modulus, for example, a uniaxially stretched film, a biaxially stretched film, and a cast film can be used. Further, the PET film, PEN film and PI film can be produced by a stretched film method and a cast method.

In the drawing, the maximum elastic modulus of the front film 42 is increased in the direction of the arrow, that is, in the direction orthogonal to the drawing. On the other hand, the maximum elastic modulus of the front film 44 increased in the direction of the arrow, that is, in the direction parallel to the drawing. Therefore, the direction having the maximum in-plane modulus of elasticity of the front film 42 and the direction having the maximum in-plane modulus of elasticity of the front film 44 are 90 degrees different.

16 is a perspective view in which the OLED display panel 41 is disassembled for each component. The direction having the maximum in-plane modulus of elasticity of the front film 42 is in the Y direction (short side direction), and the direction having the maximum in-plane modulus of elasticity of the front film 44 is in the X direction (long side direction), 90 degrees apart from each other.

In the OLED display panel 1 according to the first embodiment, the direction having the maximum in-plane modulus of elasticity of the front film 20 and the direction having the maximum in-plane modulus of elasticity of the back film 23 are disposed 90 degrees apart. In contrast, in the OLED display panel 41 according to the present embodiment, the direction having the maximum in-plane modulus of elasticity of the front film 42 and the direction having the maximum in-plane modulus of elasticity of the front film 44 are disposed 90 degrees apart. In this case, even if the OLED display panel 41 of the present application is deformed or repeatedly deformed by bending or rounding at an angle with respect to the long side direction (short side direction) for a long time, the direction having the maximum in-plane elastic modulus of the front film 42 and , Since the direction having the maximum in-plane modulus of elasticity of the front film 44 is disposed differently by 90 degrees, the force to return to the original shape of the front film 42 and the front film 44 acts, and deformation (ie, curl or Warpage) does not remain, and it can return to its original planar state when it is re-developed to a flat state.

Similarly, even if the OLED display panel 41 of the present application is deformed or repeatedly deformed by bending or rounding it in the direction of the short side, since the direction having the maximum in-plane modulus of elasticity of the front film 42 is in the direction of the short side, the front film 42 When a force to return to the original shape is applied and deformation (ie, curl or bending) does not remain, and it is redeployed to a flat state, it can return to the original flat state.

Similarly, even if the OLED display panel 41 of the present application is bent or rounded in the long side direction and deformed or repeatedly deformed for a long time, since the direction having the maximum in-plane elastic modulus of the front film 44 is in the long side direction, the front film 44 When the force to return to its original shape acts and deformation (ie, curl or bending) does not remain, and it is redeployed to a flat state, it can return to its original planar state.

Furthermore, in the OLED display panel 1 according to the first embodiment, it was necessary to consider the direction of the maximum in-plane modulus of elasticity of the back film 23, but in the OLED display panel 41 according to the second embodiment, the back film 45 ) need not consider the direction of the maximum in-plane modulus. Therefore, in actual manufacturing, since the front film 42 and the front film 44 may be manufactured and used by bonding them together with an adhesive, manufacturing of the OLED display panel becomes easy.

In this embodiment, the direction having the maximum in-plane modulus of elasticity of the front film 42 is in the short side direction, and the direction having the maximum in-plane modulus of elasticity of the front film 44 is in the direction of the long side, but the maximum in-plane modulus of elasticity of the front film 42 is in the direction of the long side. In this long side direction, the maximum in-plane elastic modulus of the front film 44 may be in the short side direction.

In addition, in the present embodiment, the direction having the maximum in-plane modulus of elasticity of the front film 42 is in the short side direction, and the direction having the maximum in-plane modulus of elasticity of the front film 44 is in the direction of the long side, which is 90 degrees different from each other, but the front film ( 42) and the direction having the maximum in-plane modulus of elasticity of the front film 44 do not have to coincide with the direction of the short side and the direction of the long side of the OLED display panel 41.

Furthermore, even if the direction having the maximum in-plane modulus of elasticity of the front film 42 and the direction having the maximum in-plane modulus of elasticity of the front film 44 do not differ by up to 90 degrees, the same effect can be obtained even if they differ by an angle smaller than 90 degrees, for example, by 30 degrees. have

According to the second embodiment, since the two front films constituting the OLED display panel are disposed in different directions having the maximum in-plane modulus of elasticity, even if the OLED display panel is deformed in a plurality of directions and stored for a long time, or the OLED display panel is stored in a plurality of directions, Even if it is repeatedly deformed in the direction, since the force to return to the original shape of the two front films acts and no deformation (ie, curl or warp) remains, it can return to the original planar state when redeployed to a flat state.

<Third Embodiment>

Next, a third embodiment of the electro-optical panel according to the present invention will be described. In the third embodiment to be described below, the same reference numerals are assigned to components common to those of the second embodiment, and description thereof is omitted. In the second embodiment, the front film having a two-layer structure is bonded together with an adhesive, but in the third embodiment, the front film having a two-layer structure is directly laminated.

Fig. 17 is a cross-sectional view schematically showing an OLED display panel 51 according to the third embodiment. As shown in FIG. 17, the OLED display panel 51 includes a flexible substrate (flexible film 10), a barrier layer (barrier film 11), a TFT layer 12, an OLED layer 13, and a color filter layer 14. , passivation layer 15, capsule encapsulation 16, circular polarizing plate 17, touch panel 18, adhesive layer 19, front film 52, hard coat 21, adhesive layer 22, and A back film 45 is provided. In this embodiment, the OLED display panel 51 is rectangular. Also, the long side of the OLED display panel 51 corresponds to the left-right direction in the drawing, and the short side of the OLED display panel 51 corresponds to the direction orthogonal to the drawing.

The OLED display panel 51 has a flexible substrate (flexible film) 10 and a barrier layer (barrier film) 11 formed thereon. On the barrier layer 11, a thin film transistor (TFT) layer 12, an OLED layer 13, and a color filter layer 14 are formed. The TFT layer 12, the OLED layer 13, and the color filter layer 14 are covered with a passivation layer 15. Furthermore, the passivation layer 15 is covered with the capsule sealing body 16 . On the capsule encapsulation body 16, a circular polarizing plate 17 is formed. A touch panel 18 is formed on the circular polarizing plate 17 .

A front film 52 is bonded to the touch panel 18 via an adhesive layer 19 . The front film 52 improves the strength of the OLED display panel 51 . The front film 52 has a first layer 53 and a second layer 54 . The front film 52 is formed from a high molecular material such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate) or PI (polyimide). As the adhesive layer 43, a pressure sensitive adhesive is used. In addition, the structure of the front film 52 will be described in detail later.

A hard coat 21 is formed on the front film 52 . In addition, a back film 45 is attached to the bottom of the flexible substrate 10 via an adhesive layer 22 . The back film 45 improves the strength of the OLED display panel 51 .

<Structure of front film>

Next, the structure of the front film 52 is explained. 18 is a diagram showing the direction of the maximum in-plane modulus of elasticity of the front film 52 in the OLED display panel 51 . As described above, the front film 52 has a first layer 53 and a second layer 54. The first layer 53 and the second layer 54 have different directions of in-plane anisotropy of elastic modulus.

In the figure, the maximum modulus of elasticity of the first layer 53 is increased in the direction of the arrow, that is, in the direction orthogonal to the figure. On the other hand, the maximum elastic modulus of the second layer 54 increased in the direction of the arrow, that is, in the direction parallel to the drawing. Therefore, the direction in which the first layer 53 has the maximum in-plane modulus of elasticity and the direction in which the second layer 54 has the maximum in-plane modulus of elasticity differ by 90 degrees.

Furthermore, the direction having the maximum in-plane modulus of elasticity of the first layer 53 is in the short side direction, and the direction of having the maximum in-plane modulus of elasticity of the second layer 54 is in the direction of the long side, 90 degrees apart from each other.

A film having two layers in different directions with in-plane anisotropy of elastic modulus can be produced by a casting method. For example, it can manufacture by manufacturing a 1st layer by the casting method, and laminate|stacking the 2nd layer which changed the casting direction on the 1st layer. Therefore, as the front film 52, a cast film can be used. In addition, PET film, PEN film, and PI film can be manufactured by a casting method.

In the OLED display panel 41 according to the second embodiment, the direction having the maximum in-plane modulus of elasticity of the front film 42 and the direction having the maximum in-plane modulus of elasticity of the front film 44 are disposed 90 degrees apart. In contrast, in the OLED display panel 51 according to the present embodiment, the direction having the maximum in-plane elastic modulus of the first layer 53 of the front film 52 and the second layer 54 of the front film 52 The directions having the maximum in-plane modulus of elasticity are arranged 90 degrees apart. In this case, even if the OLED display panel 51 of the present application is deformed or repeatedly deformed by bending or rounding at an angle with respect to the long side direction (short side direction) for a long time, the direction having the maximum in-plane elastic modulus of the first layer 53 Since the direction having the maximum in-plane modulus of elasticity of the second layer 54 and the second layer 54 are disposed 90 degrees apart, a force to return the first layer 53 and the second layer 54 to their original shapes acts, and deformation ( That is, curl or warping) does not remain, and it can return to its original planar state when it is re-developed in a flat state.

Similarly, even if the OLED display panel 51 of the present application is deformed or repeatedly deformed by bending or rounding it in the direction of the short side, since the direction having the maximum in-plane modulus of elasticity of the first layer 53 is in the direction of the short side, the first layer 53 ), the force to return to its original shape acts, and deformation (that is, curl or bending) does not remain, and it can return to its original planar state when it is redeployed to a flat state.

Similarly, even if the OLED display panel 51 of the present application is bent or rounded in the long side direction and deformed or repeatedly deformed for a long time, since the direction having the maximum in-plane elastic modulus of the second layer 54 is in the long side direction, the second layer ( 54), deformation (that is, curl or bending) does not remain due to the action of a force to return to the original shape, and it can return to its original planar state when it is re-exploited to a flat state.

Furthermore, in the OLED display panel 41 according to the second embodiment, an adhesive layer 43 for adhering the front film 42 and the front film 44 was required, but the OLED display panel 51 according to the third embodiment In , an adhesive layer is unnecessary. Therefore, it is possible to eliminate the deformation factor of the OLED display panel due to the deformation of the adhesive layer, and at the same time, the OLED display panel can be made as thin as the thickness of the adhesive layer.

In this embodiment, the direction having the maximum in-plane elastic modulus of the first layer 53 is in the short side direction, and the direction having the maximum in-plane elastic modulus of the second layer 54 is in the long side direction. The maximum in-plane modulus of elasticity may be in the long-side direction, and the maximum in-plane modulus of elasticity of the second layer 54 may be in the short-side direction.

Further, in the present embodiment, the direction having the maximum in-plane modulus of elasticity of the first layer 53 is in the short side direction, and the direction having the maximum in-plane modulus of elasticity of the second layer 54 is in the direction of the long side, which are 90 degrees apart from each other, but The direction of the first layer 53 having the maximum in-plane modulus of elasticity and the direction of the second layer 54 having the maximum in-plane modulus of elasticity do not have to coincide with the direction of the short side and the direction of the long side of the OLED display panel 51 .

Furthermore, even if the direction having the maximum in-plane modulus of elasticity of the first layer 53 and the direction having the maximum in-plane modulus of elasticity of the second layer 54 do not differ by up to 90 degrees from each other, the same angle is smaller than 90 degrees, for example, even if they differ by 30 degrees. have an effect

In this embodiment, the front film 52 has a first layer 53 and a second layer 54, and the elastic modulus of the first layer 53 and the second layer 54 has an in-plane anisotropy in the direction. this is different However, even if the front film 52 is composed of one layer and the direction in which the in-plane anisotropy of the elastic modulus is different on the front side and the back side, the same effect is obtained. For example, a resin containing cholesteric liquid crystal can be produced by a casting method. In this case, since the alignment direction of the cholesteric liquid crystal rotates in a ra-line shape in the thickness direction of the film, if an appropriate film thickness and ra-line pitch are selected, the orientation direction of the cholesteric liquid crystal is different between the film surface side and the back side. , films with different in-plane anisotropy of elastic modulus can be prepared.

According to the third embodiment, since one front film constituting the OLED display panel has two layers with different directions having the maximum in-plane modulus of elasticity, even if the OLED display panel is deformed in a plurality of directions and stored for a long time, or OLED display Even if the panel is repeatedly deformed in multiple directions, the force to return to the original shape of the front film acts and no deformation (ie, curl or warp) remains.

Although the preferred embodiment of the present invention has been described in detail above, various modifications and equivalent embodiments are possible in the future for those skilled in the art.

<Modification 1>

The OLED display panels according to the first to third embodiments are of a top emission type that emits light generated in the OLED layer toward the opposite side of the flexible substrate. However, the OLED display panel may be of a bottom emission type in which light generated in the OLED layer is emitted toward the flexible substrate side.

19 is a schematic cross-sectional view of an OLED display panel 61 according to a first modified example. The OLED display panel 61 is a bottom emission type that emits light generated in the OLED layer 13 toward the flexible substrate 10 side (ie, downward in the drawing).

As shown in Fig. 19, the LED display panel 61 has the following differences compared to the OLED display panel 1 according to the first embodiment, but has the maximum in-plane modulus of elasticity of the front film 20 in the direction Since the direction having the maximum in-plane modulus of elasticity of the backing film 23 is 90 degrees different from that of the backing film 23, the same effect as that of the OLED display panel 1 according to the first embodiment is obtained.

The circularly polarizing plate 17, the touch panel 18, the adhesive layer 19, the front film 20, and the hard coat 21 are disposed on the flexible substrate 10 side (ie, below in the drawing).

The adhesive layer 22 and the backing film 23 are disposed on the opposite side of the flexible substrate 10 (ie, upper side in the drawing).

A metal encapsulation layer 62 is disposed between the capsule encapsulation body 16 and the adhesive layer 22 .

In addition, in this modified example, the OLED display panel 1 according to the first embodiment, that is, the direction having the maximum in-plane modulus of elasticity in the front film 20 and the maximum in-plane modulus of elasticity in the back film 23 Although an example in which the OLED display panels arranged in different directions are transformed into a bottom emission type has been described, the case where the OLED display panels 41 and 51 according to the second and third embodiments are transformed into a bottom emission type is also the same.

<Modification 2>

In the OLED display panels according to the first to third embodiments, the color filter layer 14 is provided, but it may be omitted. 20 and 21 are cross-sectional views schematically showing OLED display panels 71 and 81 according to the second modified example. The OLED display panel 71 of FIG. 20 shows a case where the color filter layer 14 is removed from the OLED display panel 1 of FIG. The OLED display panel 81 in FIG. 21 shows a case where the color filter layer 14 is removed from the OLED display panel 61 in FIG. 19 . In any case, it has the same effect as the OLED display panel 1 according to the first embodiment.

Further, in this modification, the case where the color filter layer 14 is removed from the OLED display panel 1 according to the first embodiment and the case where the color filter layer 14 is removed from the OLED display panel 61 according to the first embodiment has been described, the case where the color filter layer 14 is removed from the OLED display panels 41 and 51 according to the second and third embodiments is also the same.

Although an OLED display panel has been described as an example as an embodiment, the present invention can also be applied to other electro-optical panels such as a cholesteric liquid crystal display panel, a PDLC display panel, an electrophoretic display panel, or a lighting panel.

Therefore, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the claims are also included in the present invention.

1, 24, 41, 51, 61, 71, 81: OLED display panel
10: flexible substrate (flexible film)
11: barrier layer (barrier film)
12: TFT layer
13: OLED layer
14: color filter layer
15: passivation layer
16: capsule encapsulation body
17: circular polarizer
18: touch panel
19, 22, 43: adhesive layer
20, 42, 44, 52: front film
21: hard court
23, 45: back film
25, 26: glass plate
27: sample
28: cylinder
29, 30: PET composition film
31: pressure sensitive adhesive
53: first layer
54: second layer
62: metal encapsulation layer

Claims (16)

A flexible electro-optical panel having an electro-optical element, which is an OLED element that emits light by electrical action or a liquid crystal element that controls the transmission of light by electric action, and first and second films formed from polymer materials, comprising:
The electro-optical element, the first film, and the second film are laminated;
A polarizing plate and a touch panel are sequentially stacked between the electro-optical element and the first film, and the touch panel is disposed between the polarizing plate and the first film;
The first and second films have in-plane anisotropy of elastic modulus, and a direction having the maximum elastic modulus of the first film and a direction having the maximum elastic modulus of the second film are different from each other.
According to claim 1,
An electro-optical panel in which directions having maximum elastic moduli of the first and second films are 90 degrees different from each other.
According to claim 2,
The electro-optical panel of claim 1 , wherein the electro-optical panel has a rectangular shape, and directions of maximum elastic moduli of the first and second films coincide with directions of sides of the electro-optical panel.
According to any one of claims 1 to 3,
The first and second films are disposed on both sides of the electro-optical element, the first film is disposed on a side that emits light, and the second film is disposed on a side that does not emit light. panel.
According to claim 4,
The first and second films are uniaxially stretched films, biaxially stretched films, or cast films.
According to any one of claims 1 to 3,
The first and second films are disposed on a light emitting side, and the second film is disposed between the touch panel and the first film.
According to claim 6,
The first and second films are cast films.
According to claim 6,
An electro-optical panel further comprising an adhesive disposed between the first and second films.
A flexible electro-optical panel comprising an electro-optical element, which is an OLED element that emits light by electrical action or a liquid crystal element that controls the transmission of light by electric action, and a film formed of a polymer material,
The electro-optical element and the film are laminated,
A polarizing plate and a touch panel are sequentially stacked between the electro-optical element and the film, and the touch panel is disposed between the polarizing plate and the film;
The electro-optical panel of claim 1 , wherein the film includes first and second layers having different in-plane anisotropy of elastic modulus, and a direction having a maximum elastic modulus of the first layer and a direction having a maximum elastic modulus of the second layer are different from each other.
According to claim 9,
An electro-optical panel in which directions having maximum elastic moduli of the first and second layers are 90 degrees different from each other.
According to claim 10,
The electro-optical panel of claim 1 , wherein the electro-optical panel has a rectangular shape, and directions of maximum elastic moduli of the first and second layers coincide with directions of sides of the electro-optical panel.
According to any one of claims 9 to 11,
The electro-optical panel wherein the film is disposed on a side that emits light.
According to any one of claims 9 to 11,
The electro-optical panel wherein the film is a cast film.
According to any one of claims 9 to 11,
The electro-optical panel further includes a third layer having an in-plane anisotropy of elastic modulus different from that of the first and second layers, between the first and second layers.
According to claim 1,
The electro-optical panel wherein the first and second films have a thickness of 50 μm.
According to claim 1,
The polarizing plate is an electro-optical panel that is a circular polarizing plate including a retardation film and a polarizing film.