KR102688950B1 - Polyimide based film with improved filler dispersibiltiy and display apparatus comprising the same - Google Patents

Abstract

The present invention provides a polyimide-based film comprising a polyimide-based matrix and a filler dispersed in the polyimide-based matrix, and having a true density ratio (DR) to the density gradient pipe density of 1.10 or less, and such polyimide-based film A display device including a film is provided.

Description

Polyimide-based film with excellent filler dispersibility and display device containing the same {POLYIMIDE BASED FILM WITH IMPROVED FILLER DISPERSIBILTIY AND DISPLAY APPARATUS COMPRISING THE SAME}

The present invention relates to a polyimide-based film having excellent filler dispersibility and a display device containing the same.

Polyimide (PI)-based resins have excellent insolubility, chemical resistance, heat resistance, radiation resistance, and low-temperature characteristics, and are used as automobile materials, aircraft materials, spacecraft materials, insulating coatings, insulating films, and protective films.

Recently, as display devices have become thinner, lighter, and more flexible, the use of polyimide-based films instead of glass as cover windows of display devices has been considered. In order for a polyimide-based film to be used as a cover window of a display device, the polyimide-based film needs to have mechanical properties such as excellent hardness, wear resistance, and flexibility, and optical properties such as excellent visibility and light transmittance. In order to provide desired physical properties, fillers are sometimes added to polyimide-based films.

One embodiment of the present invention seeks to provide a polyimide-based film in which fillers are uniformly dispersed within the polyimide-based resin.

One embodiment of the present invention seeks to provide a polyimide-based film having a true density ratio (Density Ratio, DR) to the density of the density gradient pipe of 1.10 or less.

One embodiment of the present invention seeks to provide a polyimide-based film having a particle volume concentration (PVC) of 5 to 38%.

One embodiment of the present invention includes a polyimide-based matrix and a filler dispersed in the polyimide-based matrix, and has a true density ratio (Density Ratio, DR) to the density gradient pipe density of 1.10 or less. A polyimide-based film is provided.

The true density ratio (DR) to the density gradient pipe density is calculated using Equation 1 below.

<Equation 1>

Density Ratio (DR) = true density / density gradient pipe density

The polyimide-based film may have a particle volume concentration (PVC) of 5 to 38%.

The particle volume concentration (PVC) is calculated using Equation 2 below.

<Equation 2>

PVC(%) = [V ₁ / (V ₁ + V ₂ )]*100

In Equation 2, V ₁ is the volume of the filler, and V ₂ is the volume of the matrix.

The filler may include silica (SiO ₂ ).

At least a portion of the silica (SiO ₂ ) may be surface treated with an organic compound having an alkoxy group.

The average particle diameter of the filler may be 5 to 50 nm.

The content of the filler may be 5 to 50% by weight based on the total weight of the polyimide-based film.

The polyimide-based film may have a Young's Modulus of 5.0 GPa or more.

The polyimide-based film may have an elongation of 15% or more.

The polyimide-based film may have an indentation hardness of 45 or more.

The polyimide-based film may have a yellowness of 3 or less.

The polyimide-based film may have a haze of 1% or less.

The polyimide-based film may have a light transmittance of 85% or more.

Another embodiment of the present invention provides a display device including a display panel and the polyimide-based film disposed on the display panel.

According to one embodiment of the present invention, a polyimide-based film with excellent filler dispersibility can be produced.

Generally, when filler is dispersed in a polyimide-based film, the haze of the polyimide-based film may decrease, but according to one embodiment of the present invention, the filler dispersibility in the polyimide-based film is excellent, so that the haze of the polyimide-based film is 1.10 or less. It can have a true density ratio (DR) to the density gradient pipe density. As a result, the polyimide-based film of the present invention can have excellent optical properties and excellent mechanical properties.

The polyimide-based film according to an embodiment of the present invention has excellent optical and mechanical properties, and when used as a cover window of a display device, it can effectively protect the display surface of the display device.

1 is a schematic diagram of a polyimide-based film according to an embodiment of the present invention.
Figure 2 shows the difference in pores inside the film according to the true density ratio (DR) to the density gradient tube density of the film.
Figure 3 shows the difference in pores inside the film depending on the particle volume concentration (PVC) of the film.
Figure 4 is a schematic diagram explaining the dispersion state of filler in a polyimide-based film according to an embodiment of the present invention.
Figure 5 is a cross-sectional view of a portion of a display device according to another embodiment of the present invention.
Figure 6 is an enlarged cross-sectional view of portion "P" in Figure 5.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. However, the embodiments described below are provided for illustrative purposes only to facilitate a clear understanding of the present invention, and do not limit the scope of the present invention.

The shape, size, ratio, angle, number, etc. shown in the drawings for explaining embodiments of the present invention are illustrative, and the present invention is not limited to the matters shown in the drawings. Like components may be referred to by the same reference numerals throughout the specification. In describing the present invention, if it is determined that a detailed description of related known technology may unnecessarily obscure the gist of the present invention, the detailed description is omitted.

When 'includes', 'has', 'consists of', etc. mentioned in this specification are used, other parts may be added unless the expression 'only' is used. If a component is expressed in the singular, the plural is included unless specifically stated. In addition, when interpreting components, it is interpreted to include the margin of error even if there is no separate explicit description.

In the case of a description of a positional relationship, for example, if the positional relationship of two parts is described as 'on top', 'on the top', 'on the bottom', 'next to', etc., 'immediately' Alternatively, one or more other parts may be placed between the two parts, unless the expression 'directly' is used.

Spatially relative terms such as “below, beneath,” “lower,” “above,” and “upper” refer to one element or component as shown in the drawing. It can be used to easily describe the correlation with other elements or components. Spatially relative terms should be understood as terms that include different directions of the element during use or operation in addition to the direction shown in the drawings. For example, if an element shown in the drawings is turned over, an element described as “below” or “beneath” another element may be placed “above” the other element. Accordingly, the illustrative term “down” may include both downward and upward directions. Likewise, the illustrative terms “up” or “on” can include both up and down directions.

In the case of a description of a temporal relationship, for example, if a temporal relationship is described as 'after', 'successfully after', 'after', 'before', etc., 'immediately' or 'directly' Unless the expression is used, non-continuous cases may also be included.

Although first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are merely used to distinguish one component from another. Accordingly, the first component mentioned below may also be the second component within the technical spirit of the present invention.

The term “at least one” should be understood to include all possible combinations from one or more related items. For example, “at least one of the first, second, and third items” means each of the first, second, or third items, as well as two of the first, second, and third items. It can mean a combination of all items that can be presented from more than one.

Each feature of the various embodiments of the present invention can be combined or combined with each other, partially or entirely, and various technical interconnections and operations are possible, and each embodiment may be implemented independently of each other or may be implemented together in a related relationship. It may be possible.

Figure 1 is a schematic diagram of a polyimide-based film 100 according to an embodiment of the present invention.

As shown in FIG. 1, the polyimide-based film 100 according to an embodiment of the invention includes a polyimide-based matrix 110 and a filler 120 dispersed in the polyimide-based matrix.

In the polyimide-based film 100 according to an embodiment of the present invention, the true density ratio (DR) of the film 100 to the density-gradient tube density is 1.10. It is as follows.

The true density ratio (Density Ratio, DR) of the film 100 to the density of the density gradient pipe is calculated using Equation 1 below.

<Equation 1>

Density Ratio (DR) = true density / density gradient pipe density

True density refers to solid density and refers to the density of only the part that is completely filled with material, excluding the voids between particles. According to one embodiment of the present invention, the true density is the density of only the portion filled with the polyimide-based matrix 110 and the filler 120 excluding the voids.

The true density may vary depending on the size of the measurement film 100 specimen during measurement. Therefore, according to an embodiment of the present invention, the true density of the film 100 can be obtained through powder analysis.

Specifically, a film 100 specimen ^{( 10} Fill the freeze grinder (Japan Analytical Industry, JFC-300) with more than 2/3 of liquid nitrogen, combine the sample holder containing the cut specimen with the freeze grinder, and then close the chamber. Using a freeze grinder, grind the specimen for more than 15 minutes pre-cool / 15 minutes run. The true density of the pulverized film (100) specimen was measured seven times using Micromeritics' AccuPyc 1340 Pycnometer equipment (using helium gas). Excluding the highest and lowest values among the measured true density values of the film 100, the average of the remaining true density values is the true density of the film 100 in the present invention.

Density-gradient tube density refers to the density measured using a density gradient tube. A density gradient tube is a method of measuring density, and is also called a density gradient tube.

According to one embodiment of the present invention, the density gradient tube density of the film 100 can be obtained using a density gradient tube according to the standard ASTM D1505.

Specifically, the density gradient tube is to create a gradient of density between the liquid with a large specific gravity in the lower part of the glass cylinder and the liquid with a smaller specific gravity in the upper part. When a piece of film (100) is placed in such a density gradient tube, the It hangs and stops at the same position as the density, and the density gradient tube density of the film (100) specimen can be known through the density gradient at that position. The density gradient of the density gradient pipe can be determined by inserting a glass spherical float whose specific gravity is known, by measuring the specific gravity of zinc chloride aqueous solutions of various concentrations in advance and fixing them in the density gradient pipe, or by using a method where the specific gravity of the density gradient pipe is different from each other. This can be determined through a colorimetric method using a dye that dissolves only in one of the other liquids.

Hereinafter, with reference to FIG. 2, the true density ratio (DR) to the density gradient pipe density of the film 100 will be described in detail. Figure 2 shows the difference in pores inside the film 100 according to the true density ratio (DR) to the density gradient tube density of the film 100.

The true density ratio (DR) to the density gradient tube density of the film 100 is the degree of pores (porosity, porosity) existing in the film 100 as the density gradient tube density and true density of the film 100. It is expressed using the ratio of . The true density is the density of the matrix 110 and the filler 120 excluding the voids in the film 100, and the density gradient pipe density is the density of the film 100 including the voids, and is the ratio of the true density and the density gradient pipe density. Through this, the porosity of the film 100 can be expressed.

As shown in FIG. 2, as the true density ratio (DR) of the film 100 to the density gradient pipe density increases, the voids of the film 100 increase, and conversely, the true density ratio (DR) to the density gradient pipe density increases. As DR) decreases, the voids of the film 100 decrease.

In general, when the film 100 includes the filler 120, differences in pores of the film 100 may occur depending on the degree of dispersion of the filler 120. If the dispersibility of the filler 120 is small and the fillers 120 are clustered together, the space between the fillers may not be sufficiently filled by the matrix 110, and voids may occur. On the other hand, when the filler 120 is well dispersed, the matrix 110 and the filler 120 are sufficiently well mixed, and the space between the fillers can be sufficiently filled with the matrix 110, thereby creating voids. decreases.

As the voids in the film 100 decrease, the tensile strength, Young's modulus, elongation, indentation hardness, and light transmittance of the film 100 increase, and the yellowness and haze decrease. Accordingly, the mechanical properties of the film 100, such as wear resistance and flexibility, and the optical properties, such as light transmittance and visibility, are improved.

According to one embodiment of the present invention, the true density ratio (DR) of the film 100 to the density of the density gradient pipe is 1.10 or less.

When the true density ratio (DR) to the density gradient pipe density is greater than 1.10, the filling effect of the filler 120 in the film 100 is reduced, thereby improving the hardness and Young's Modulus of the film 100. decreases. In addition, due to the increase in voids in the film 100 due to the agglomeration of the filler 120, a problem occurs in which the elongation and indentation hardness of the film 100 are reduced. Additionally, the haze of the film 100 increases due to the agglomeration of the filler 120.

In the polyimide-based film 100 according to an embodiment of the present invention, the particle volume concentration (PVC) of the film 100 is 5 to 38%.

The particle volume concentration (PVC) of the film 100 is calculated using Equation 2 below.

<Equation 2>

PVC(%) = [V ₁ / (V ₁ + V ₂ )]*100

In Equation 2, V ₁ is the volume of the filler, and V ₂ is the volume of the matrix.

Hereinafter, with reference to FIG. 3, particle volume concentration (PVC) will be described in detail. Figure 3 shows the difference in pores inside the film 100 according to the particle volume concentration (PVC) of the film 100.

Particle volume concentration (PVC) is expressed as a percentage (%) of the volume occupied by the filler 120 with respect to the total volume of the matrix 110 and the filler 120 in the film 100.

As shown in FIG. 3, when the particle volume concentration (PVC) of the film 100 decreases, the pores of the film 100 decrease, and when the particle volume concentration (PVC) increases, the pores of the film 100 Voids increase.

As the particle volume concentration (PVC) of the film 100 increases, the volume occupied by the filler 120 in the film 100 increases, and the average distance between fillers decreases. When the average distance between fillers becomes shorter, it is difficult for the matrix 110 to fill the space between fillers, thereby increasing voids.

The volume of the filler (V ₁ ) can be calculated by dividing the mass of the filler by the density. Specifically, the volume (V ₁ ) of the filler can be calculated by measuring the mass and density of the filler included in the film 100, respectively. For example, the mass of the filler can be known by measuring the weight of the filler added when manufacturing the film 100. The density of the filler can be measured using the true density measurement method or the density gradient pipe density measurement method described above.

The volume of the matrix (V ₂ ) can be calculated by dividing the mass of the matrix by the density. Specifically, the volume (V ₂ ) of the matrix can be calculated by measuring the mass and density of the matrix included in the film 100, respectively. For example, the mass of the matrix can be known by measuring the weight of the matrix added when manufacturing the film 100. The density of the matrix can be measured using the true density measurement method or the density gradient pipe density measurement method described above.

According to one embodiment of the present invention, the particle volume concentration (PVC) of the film 100 is 5 to 38%.

When the particle volume concentration (PVC) is less than 5%, the effect of improving the mechanical properties of the film 100 by the filler 120 is minimal. In addition, when the particle volume concentration (PVC) is more than 38%, discontinuity occurs at the contact surface between the filler 120 and the matrix 110, resulting in a decrease in elongation and indentation hardness.

According to one embodiment of the present invention, the polyimide-based matrix 110 has light transparency. Additionally, the polyimide-based matrix 110 has flexible characteristics. For example, the polyimide-based matrix 110 has bending properties, folding properties, and rollable properties.

The polyimide-based matrix 110 includes polyimide-based resin. The polyimide-based matrix 110 may be made of, for example, polyimide-based resin.

The polyimide-based matrix 110 according to an embodiment of the present invention may be manufactured from monomer components including dianhydride and diamine.

More specifically, the polyimide-based matrix 110 according to an embodiment of the present invention has an imide repeating unit formed by dianhydride and diamine.

However, the polyimide-based matrix 110 according to an embodiment of the present invention is not limited thereto. The polyimide-based matrix 110 according to an embodiment of the present invention may be manufactured from monomer components that further include a dicarbonyl compound in addition to dianhydride and diamine. Therefore, the polyimide-based matrix 110 according to an embodiment of the present invention may have an imide repeating unit and an amide repeating unit. The polyimide-based matrix 110 having an imide repeating unit and an amide repeating unit includes, for example, polyamide-imide resin.

Therefore, the polyimide-based matrix 110 according to an embodiment of the present invention may include a polyimide resin or a polyamide-imide resin.

According to an embodiment of the present invention, the polyimide-based resin used as the polyimide-based matrix 110 may have excellent mechanical and optical properties.

The polyimide-based matrix 110 may have a thickness sufficient to protect the polyimide-based film 100 of the display panel. For example, the polyimide-based matrix 110 may have a thickness of 10 to 100 μm.

The polyimide-based matrix 110 may have an average light transmittance of 85% or more and a yellowness of 5 or less in the visible light region measured with a UV spectrophotometer, based on a thickness of 10 to 100 μm.

According to one embodiment of the present invention, the filler 120 may be an inorganic material or an organic material. The filler 120 may have the shape of a particle. According to one embodiment of the present invention, an inorganic filler may be used.

According to one embodiment of the present invention, the filler 120 is silica (SiO ₂ ), zirconia (ZrO ₂ ), alumina (Al ₂ O ₃ ), titanium dioxide (TiO ₂ ), It may include at least one of styrene and acrylic. For example, inorganic silica (SiO ₂ ) particles may be used as the filler 120 .

According to one embodiment of the present invention, at least a portion of the silica (SiO ₂ ) used as the filler 120 may be surface treated. More specifically, surface-treated silica (SiO ₂ ) particles may be used as the filler 120.

According to one embodiment of the present invention, at least a portion of silica (SiO ₂ ) used as the filler 120 may be surface treated with an organic compound having an alkoxy group. For example, silica (SiO ₂ ) particles surface-treated with at least one of substituted or unsubstituted alkylalkoxysilane and phenylalkoxysilane may be used as the filler 120.

Specifically, silica (SiO ₂ ) particles surface-treated with methylalkoxysilane, ethylalkoxysilane, or phenylalkoxysilane may be used as the filler 120. More specifically, silica (SiO ₂ ) particles surface-treated with trimethoxy(methyl)silane or phenyltrimethoxysilane may be used as the filler 120.

According to one embodiment of the present invention, the filler 120 may have a unit structure represented by the following Chemical Formulas 1 to 7.

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

In Formulas 1 to 6, R may each independently be at least one of an alkyl group with 1 to 10 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, a cycloalkyl group with 3 to 10 carbon atoms, and a phenyl group with 6 to 18 carbon atoms.

The polyimide-based film 100 according to an embodiment of the present invention has excellent mechanical and optical properties.

With regard to optical properties, the polyimide-based film 100 according to an embodiment of the present invention may have a yellowness of 3 or less. Additionally, the polyimide-based film 100 according to an embodiment of the present invention may have a haze of 1% or less. The polyimide-based film 100 according to an embodiment of the present invention may have a light transmittance of 85% or more.

Additionally, with regard to mechanical properties, the polyimide-based film 100 according to an embodiment of the present invention may have a Young's modulus of 5.0 GPa or more. Additionally, the polyimide-based film 100 according to an embodiment of the present invention may have an elongation of 15% or more. Additionally, the polyimide-based film 100 according to an embodiment of the present invention may have an indentation hardness of 45 or more.

According to one embodiment of the present invention, in order for the polyimide-based film 100 to have excellent optical and mechanical properties, the particle size of the filler 120, the content of the filler 120, and the gap between particles are adjusted. You can.

In addition, in order for the filler 120 to be uniformly mixed into the polyimide-based matrix 110 so that the polyimide-based film 100 has excellent optical and mechanical properties, an embodiment of the present invention uses polyimide A new mixing method of the polyimide-based polymer constituting the system matrix 110 and the filler 120 is provided.

According to one embodiment of the present invention, the filler 120 may have an average particle diameter of 5 to 50 nm. If the average particle diameter of the filler 120 is less than 5 nm, the dispersibility of the filler 120 may decrease and the fillers 120 may aggregate. On the other hand, if the average particle diameter of the filler 120 exceeds 50 nm, the optical properties of the polyimide-based film 100 including the filler 120 may deteriorate. For example, when the filler 120 having an average particle diameter exceeding 50 nm is included in excess, the haze of the polyimide-based film 100 may increase.

In addition, if the average particle diameter of the filler 120 is less than 5 nm, the mechanical strength of the polyimide film 100 is reduced due to the aggregate of the filler 120 at the portion where the filler 120 is aggregated, The tensile strength, Young's Modulus, and indentation hardness of the polyimide film 100 may decrease. If the average particle diameter of the filler 120 exceeds 50 nm, the elongation of the polyimide-based film 100 may be less than 15%.

In addition, if the average particle diameter of the filler 120 is less than 5 nm, the dispersibility of the filler 120 may be reduced, and if the average particle diameter of the filler 120 exceeds 50 nm, the gap between the fillers 120 may not be sufficiently secured. Therefore, the true density ratio (DR) to density gradient pipe density may exceed 1.10.

According to another embodiment of the present invention, the filler 120 may have an average particle diameter of 10 to 20 nm, or may have an average particle diameter of 10 to 15 nm.

When the polyimide film 100 includes a filler 120 having a nanometer particle size, the optical properties of the polyimide film 100 may be improved due to light scattering by the filler 120. Additionally, when the polyimide film 100 includes the filler 120, the mechanical properties of the polyimide film 100 may be improved.

According to one embodiment of the present invention, the content of the filler 120 may range from 5 to 50% by weight based on the total weight of the polyimide-based film 100.

When the content of the filler 120 is less than 5% by weight based on the total weight of the polyimide-based film 100, the light scattering effect by the filler 120 is insignificant, and the light transmittance improvement effect of the polyimide-based film 100 is reduced. It may barely appear. In addition, when the content of the filler 120 is less than 5% by weight based on the total weight of the polyimide-based film 100, the tensile strength, Young's modulus, elongation, and hardness of the polyimide-based film 100 are improved. It may be insignificant.

On the other hand, when the content of the filler 120 exceeds 50% by weight based on the total weight of the polyimide-based film 100, the dispersibility of the filler 120 is reduced, thereby reducing the haze ( Haze) may decrease, and the light transmittance of the polyimide-based film 100 may decrease due to excessive filler 120 blocking light.

Figure 4 is a schematic diagram explaining the dispersion state of the filler 120 in the polyimide-based film 100 according to an embodiment of the present invention.

As shown in FIG. 4, some of the fillers 120 are dispersed and spaced apart from each other, while some form an aggregation. In FIG. 4, “Group A” represents fillers 120 forming a group. The fillers 120 other than those of “Group A” represent fillers 120 that are not clustered but dispersed (parts other than Group A). The smaller the number of fillers 120 forming a group such as “Group A” in FIG. 4, the more uniformly the fillers 120 are dispersed within the polyimide-based film 100.

When the amount of filler 120 forming a group such as "Group A" in FIG. 4 is small, the true density ratio (DR) to the density gradient pipe density is 1.10 or less, and the polyimide-based film 100 has excellent density. It can have tensile strength, Young's Modulus, elongation, and indentation hardness. In addition, when the amount of filler 120 forming a group such as "Group A" is small, the particle volume concentration (PVC) is in the range of 5 to 38%, so that the polyimide-based film 100 has excellent tensile strength and It can have Young's Modulus.

Generally, when filler 120 is included, if the filler 120 is not sufficiently uniformly dispersed, the tensile strength, Young's modulus, elongation, indentation hardness, and light transmittance of the polyimide-based film 100 decrease. and yellowness and haze may increase, and the mechanical and optical properties of the polyimide-based film 100 may deteriorate. However, according to an embodiment of the present invention, the true density ratio (DR) to the density gradient pipe density is set to 1.10 or less, so that the tensile strength, Young's modulus, elongation, and press fit of the polyimide-based film 100 A decrease in hardness and light transmittance can be prevented, and an increase in yellowness and haze can be prevented.

In addition, according to an embodiment of the present invention, by setting the particle volume concentration (PVC) to 5 to 38%, it is possible to prevent a decrease in the tensile strength and Young's modulus of the polyimide-based film 100.

According to one embodiment of the present invention, the true density ratio (DR) of the polyimide-based film 100 to the density gradient pipe density is 1.10 or less, and the polyimide-based film 100 has a Young's modulus of 5.0 GPa or more. ) can have.

Additionally, according to one embodiment of the present invention, the polyimide-based film 100 may have an elongation of 15% or more.

Additionally, according to an embodiment of the present invention, the polyimide-based film 100 may have an indentation hardness of 45 or more.

Additionally, according to an embodiment of the present invention, the polyimide-based film 100 may have a light transmittance of 85% or more.

Additionally, according to one embodiment of the present invention, the polyimide-based film 100 may have a haze of 1% or less.

Additionally, according to an embodiment of the present invention, the polyimide-based film 100 may have a yellowness of 3.0 or less.

FIG. 5 is a cross-sectional view of a portion of the display device 200 according to another embodiment of the present invention, and FIG. 6 is an enlarged cross-sectional view of portion “P” of FIG. 5 .

Referring to FIG. 5, a display device 200 according to another embodiment of the present invention includes a display panel 501 and a polyimide-based film 100 on the display panel 501.

Referring to FIGS. 5 and 6 , the display panel 501 includes a substrate 510, a thin film transistor (TFT) on the substrate 510, and an organic light emitting device 570 connected to the thin film transistor (TFT). The organic light emitting device 570 includes a first electrode 571, an organic light emitting layer 572 on the first electrode 571, and a second electrode 573 on the organic light emitting layer 572. The display device 200 disclosed in FIGS. 5 and 6 is an organic light emitting display device.

Substrate 510 may be made of glass or plastic. Specifically, the substrate 510 may be made of plastic such as polyimide-based resin or polyimide-based film. Although not shown, a buffer layer may be disposed on the substrate 510.

A thin film transistor (TFT) is disposed on the substrate 510. The thin film transistor (TFT) includes a semiconductor layer 520, a gate electrode 530 that is insulated from the semiconductor layer 520 and overlaps at least a portion of the semiconductor layer 520, a source electrode 541 connected to the semiconductor layer 520, and It includes a drain electrode 542 spaced apart from the source electrode 541 and connected to the semiconductor layer 520.

Referring to FIG. 6, a gate insulating film 535 is disposed between the gate electrode 530 and the semiconductor layer 520. An interlayer insulating film 551 may be disposed on the gate electrode 530, and a source electrode 541 and a source electrode 541 may be disposed on the interlayer insulating film 551.

The planarization film 552 is disposed on the thin film transistor (TFT) to planarize the top of the thin film transistor (TFT).

The first electrode 571 is disposed on the planarization film 552. The first electrode 571 is connected to the thin film transistor (TFT) through a contact hole provided in the planarization film 552.

The bank layer 580 is disposed on a portion of the first electrode 571 and the planarization film 552 to define a pixel area or a light emitting area. For example, the bank layer 580 may be arranged in a matrix structure at the boundary area between a plurality of pixels, thereby defining a pixel area by the bank layer 580.

The organic light emitting layer 572 is disposed on the first electrode 571. The organic light emitting layer 572 may also be disposed on the bank layer 580. The organic light-emitting layer 572 may include one light-emitting layer or two light-emitting layers stacked top and bottom. This organic light-emitting layer 572 may emit light having any one of red, green, and blue colors, and may also emit white light.

The second electrode 573 is disposed on the organic light emitting layer 572.

The organic light emitting device 270 may be formed by stacking the first electrode 571, the organic light emitting layer 572, and the second electrode 573.

Although not shown, when the organic emission layer 572 emits white light, each pixel may include a color filter to filter the white light emitted from the organic emission layer 572 by wavelength. A color filter is formed on the path of light.

A thin film encapsulation layer 590 may be disposed on the second electrode 573. The thin film encapsulation layer 590 may include at least one organic layer and at least one inorganic layer, and at least one organic layer and at least one inorganic layer may be alternately disposed.

A polyimide-based film 100 is disposed on the display panel 501 having the laminated structure described above. The polyimide-based film 100 includes a polyimide-based matrix 110 and filler 120 dispersed in the polyimide-based matrix 110.

The polyimide-based film 100 according to an embodiment of the present invention can be manufactured by a hybrid mixing method that combines solution-to-solution mixing and solution-to-powder mixing.

According to an embodiment of the present invention, the method of manufacturing the polyimide-based film 100 includes manufacturing a polyimide-based resin powder, dissolving a first content of the polyimide-based resin powder in a first solvent, and dissolving the polyimide-based resin powder in the first solvent. Preparing a resin solution, dispersing the filler in a second solvent to prepare a filler dispersion, mixing the filler dispersion and the polyimide resin solution to prepare a first mixed solution, and adding polyimide resin powder to the first mixed solution. It includes adding and dissolving a second amount of to prepare a second mixed solution.

According to one embodiment of the present invention, the polyimide resin powder is divided and mixed with the filler dispersion at least twice.

Specifically, the first content of the polyimide-based resin powder is dissolved in the first solvent and mixed with the filler dispersion in the form of a polyimide-based resin solution. The first content may be 0.5 to 10% of the filler weight, preferably 1 to 5%.

Additionally, the second content of the polyimide resin powder is added in powder form. Specifically, the second content of the polyimide-based resin powder may be added in powder form to the first mixed solution consisting of a filler dispersion and a polyimide-based resin solution.

The second content of the polyimide resin powder may be 10 to 200 times the first content. More specifically, the second content of the polyimide resin powder may be 60 to 200 times the first content.

According to one embodiment of the present invention, before adding the second content of polyimide resin powder to the first mixed solution, the step of adding a third solvent to the first mixed solution may be further included. The third solvent may be the same as or different from the first solvent. According to one embodiment of the present invention, the same solvent as the first solvent may be used as the third solvent.

DMAc (N,N-Dimethylacetamide) may be used as the first solvent. DMAc (N,N-Dimethylacetamide) or methyl ethyl ketone (MEK) may be used as the second solvent. DMAc (N,N-Dimethylacetamide) may be used as a third solvent. However, one embodiment of the present invention is not limited to this, and other known solvents may be used as the first, second, and third solvents.

According to one embodiment of the present invention, first, a portion (first content) of the polyimide resin powder is dissolved in a solvent and then mixed with the filler dispersion. Accordingly, the dispersibility of the filler is improved.

For reference, when polyimide resin powder is directly added to the filler dispersion in which the filler is dispersed, the solvent instantly penetrates into the powder from the surface of the powder, and at this time, the concentration around the powder surface instantly increases, causing the filler to Agglomeration may occur.

On the other hand, according to one embodiment of the present invention, by first adding the already dissolved polyimide resin to the filler dispersion containing a solvent, the polymer chains of the polyimide resin distributed between the fillers can prevent agglomeration between fillers. You can. Afterwards, even if the polyimide resin powder is added again (second content added), agglomeration between fillers does not occur. Accordingly, the agglomeration phenomenon of the filler is prevented and the dispersibility of the filler is improved.

A polyimide-based film 100 including a uniformly dispersed filler can be manufactured by a hybrid mixing method that combines solution-to-solution mixing and solution-to-powder mixing according to an embodiment of the present invention.

According to an embodiment of the present invention, a high degree of freedom between the filler 120 and the polyimide-based resin can be maintained, and an environment in which dispersibility is easy can be created. Accordingly, the filler 120 and the polyimide-based resin can be combined in a high degree of freedom state, and the filler 120 is formed into a polyimide-based film ( 100) can be manufactured.

According to one embodiment of the present invention, silica particles may be used as the filler 120. Silica particles can be made from, for example, tetraethyltriethoxysilane.

Specifically, ethanol and tetraethyltriethoxysilane (TEOS, Si(OC ₂ H ₅ ) ₄ ) were added to the reactor and stirred at room temperature, NH ₄ OH was added thereto, and the reaction product obtained by stirring was filtered. and washed with ethanol, then dried under reduced pressure to produce silica particles [SiO ₂ ] with an average particle diameter of about 20 nm.

Silica dispersion may be used as the filler 120 dispersion. The silica dispersion can be prepared, for example, by adding dimethylacetamide (DMAc) and silica particles to a reactor and stirring.

Hereinafter, the present invention will be described in more detail with reference to exemplary preparation examples and examples. However, the present invention is not limited to the manufacturing examples or examples described below.

<Preparation Example 1: Preparation of polyimide polymer solid content>

After passing nitrogen through a 1L reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller, and cooler, 776.655 g of DMAc (N,N-Dimethylacetamide) was filled, the temperature of the reactor was set to 25°C, and then TFDB 54.439 g (0.17 mol) was dissolved and the solution was maintained at 25°C. 15.005 g (0.051 mol) of BPDA was added here and stirred for 3 hours to completely dissolve BPDA, and then 22.657 g (0.051 mol) of 6FDA was added and completely dissolved. After lowering the reactor temperature to 10°C, 13.805 g (0.068 mol) of TPC was added and reacted at 25°C for 12 hours to obtain a polymer solution with a solid concentration of 12% by weight.

17.75 g of pyridine and 22.92 g of acetic anhydride were added to the obtained polymer solution, stirred for 30 minutes, stirred again at 70°C for 1 hour, cooled to room temperature, and 20 L of methanol was added to the obtained polymer solution to precipitate the solid content. The solid content was filtered and pulverized, washed again with 2L of methanol, and then dried in vacuum at 100°C for 6 hours to obtain a polyimide-based polymer solid content in powder form. The solid content of the polyimide-based polymer produced here is a solid content of polyamide-imide polymer.

<Example 1>

After filling 35.42 parts by weight of DMAc (first solvent) in a 1L reactor, the temperature of the reactor was maintained at 10 ^o C and stirred for a certain period of time. Afterwards, 0.36 parts by weight (first content) of polyamide-imide (polyimide-based resin powder) of the solid powder prepared in Preparation Example 1 was added, stirred for 1 hour, and then raised to 25°C to form a liquid polyimide-based A resin solution was prepared.

23.85 parts by weight of silica dispersion A (SSD_330T, Ranco), which consists of 30% by weight silica particles with an average particle diameter of 10nm dispersed in DMAc (N,N-dimethylacetamide) solution (second solvent), was filled into another 1L reactor. While maintaining the temperature of the reactor at 25°C, the prepared liquid polyimide-based resin solution was slowly introduced over 1 hour using a cylinder pump to produce a first mixed solution of silica dispersion and polyimide-based resin solution. Manufactured.

348.23 parts by weight of DMAc, a third solvent, was added to the first mixed solution, stirred, and 64.04 parts by weight (second content) of polyamide-imide (polyimide-based resin powder) of the solid powder prepared in Preparation Example 1 was added and stirred. Thus, a second mixed solution was prepared. The second mixed solution is a polyimide resin solution in which silica particles are dispersed.

The obtained second mixed liquid was casted. A casting substrate is used for casting. There is no particular limitation on the type of casting substrate. As a casting substrate, a glass substrate, stainless steel (SUS) substrate, Teflon substrate, etc. may be used. According to one embodiment of the present invention, an organic substrate may be used as a casting substrate.

Specifically, the obtained second mixed solution was applied to a glass substrate, casted, and dried with hot air at 120°C for 30 minutes to produce a film. The produced film was peeled from the glass substrate and pinned to the frame.

The frame on which the film was fixed was placed in a vacuum oven and slowly heated from 100°C to 280°C for 2 hours, then slowly cooled and separated from the frame to obtain a polyimide-based film. Again, the polyimide film was heat treated at 250°C for 5 minutes.

As a result, a polyimide-based film 100 with a thickness of 50 μm, including a polyimide-based matrix 110 and a silica-based filler 120 dispersed in the polyimide-based matrix, was completed.

<Examples 2 to 7>

In the same manner as Example 1, polyimide-based films of Examples 2 to 7 were prepared by varying only the contents of the silica dispersion, the content of the silica dispersion, the first content, the second content, the first solvent content, and the third solvent. .

The specific silica dispersion of Examples 1 to 7, the content of the silica dispersion, the first content, the second content, the first solvent content, and the third solvent content are shown in Table 1 below.

<Comparative Example 1>

In the same manner as in Example 1, a polyimide-based film 100 was manufactured by varying the silica dispersion, the content of the silica dispersion, the first content, the second content, the first solvent content, and the third solvent content.

The specific silica dispersion of Comparative Example 1, the content of the silica dispersion, the first content, the second content, the first solvent content, and the third solvent content are shown in Table 1 below.

<Comparative Example 2>

A 1L reactor was filled with 35.80 parts by weight of silica dispersion C (50nmSP-AD1, Admatechs), which consists of 20% by weight of silica particles with an average particle diameter of 50nm dispersed in a DMAc (N,N-dimethylacetamide) solution (second solvent). Then, 371.73 parts by weight of DMAc (third solvent) was added and stirred. To the stirred solution, 64.40 parts by weight (second content) of polyamide-imide (polyimide-based resin powder) of the solid powder prepared in Preparation Example 1 was added and stirred to obtain a mixed solution of silica dispersion and polyimide-based resin. was manufactured. The mixed solution is a polyimide resin solution in which silica particles are dispersed.

The obtained mixed solution was cast. The polyimide-based film 100 was manufactured in the same manner as in Example 1 for casting and subsequent processes.

<Comparative Example 3>

Silica dispersion D (DMAc-ST-ZL, Nissan) 35.80 weight, consisting of silica particles with an average particle diameter of 70 nm dispersed at a content of 20% by weight in a DMAc (N,N-dimethylacetamide) solution (second solvent) in a 1L reactor. After filling the mixture, 371.06 parts by weight of DMAc (third solvent) was added and stirred. To the stirred solution, 64.40 parts by weight (second content) of polyamide-imide (polyimide-based resin powder) of the solid powder prepared in Preparation Example 1 was added and stirred to obtain a mixed solution of silica dispersion and polyimide-based resin. was manufactured. The mixed solution is a polyimide resin solution in which silica particles are dispersed.

The obtained mixed solution was cast. The polyimide-based film 100 was manufactured in the same manner as in Example 1 for casting and subsequent processes.

<Comparative Examples 4 to 7>

In the same manner as in Example 1, the polyimide-based films 100 of Comparative Examples 4 to 7 were prepared by varying the silica dispersion, the content of the silica dispersion, the first content, the second content, the first solvent content, and the third solvent content. was manufactured.

The specific silica dispersion, the content of the silica dispersion, the first content, the second content, the first solvent content, and the third solvent content of Comparative Examples 4 to 7 are shown in Table 1 below.

division silica dispersion Content of silica dispersion
(part by weight) first content
(part by weight) First solvent content
(part by weight) second content
(part by weight) Tertiary solvent content
(part by weight) Example 1 Silica dispersion A
(SSD_330T, Ranco)
Average particle size: 10nm
Content of silica particles in dispersion: 30% by weight 23.85 0.36 35.42 64.04 348.23 Example 2 Silica Dispersion A (SSD_330T, Ranco)
Average particle size: 10nm
Content of silica particles in dispersion: 30% by weight 115.60 1.73 171.67 62.67 284.01 Example 3 Silica Dispersion A (SSD_330T, Ranco)
Average particle diameter: 11nm
Content of silica particles in dispersion: 30% by weight 175.70 2.64 260.91 61.76 241.94 Example 4 Silica dispersion C
(50nmSP-AD1, Admatechs)
Average particle diameter: 50nm
Content of silica particles in dispersion: 20% by weight 35.80 0.36 35.44 64.04 336.29 Example 5 Silica dispersion B
(SSK230U2, Ranco)
Average particle diameter: 30nm
Content of silica particles in dispersion: 30% by weight 92.00 1.38 136.62 63.02 300.53 Example 6 Silica Dispersion A (SSD_330T, Ranco)
Average particle size: 10nm
Content of silica particles in dispersion: 30% by weight 115.60 0.35 34.33 64.05 284.01 Example 7 Silica Dispersion A (SSD_330T, Ranco)
Average particle size: 10nm
Content of silica particles in dispersion: 30% by weight 92.0 2.76 273.24 61.64 300.53 Comparative Example 1 Silica dispersion A
(SSD_330T, Ranco)
Average particle size: 10nm
Content of silica particles in dispersion: 30% by weight 262.40 3.94 389.66 60.46 181.25 Comparative Example 2 Silica Dispersion C (50nmSP-AD1, Admatechs)
Average particle diameter: 50nm
Content of silica particles in dispersion: 20% by weight 35.80 0.00 0.00 64.40 371.73 Comparative Example 3 Silica dispersion D
(DMAc-ST-ZL, Nissan)
Average particle diameter: 70nm
Content of silica particles in dispersion: 20% by weight 35.80 0.00 0.00 64.40 371.06 Comparative Example 4 Silica dispersion E
(Y100SP-CD1, Admatechs)
Average particle size: 100nm
Content of silica particles in dispersion: 20% by weight 35.80 0.36 35.44 64.04 336.29 Comparative Example 5 Silica Dispersion A (SSD_330T, Ranco)
Average particle size: 10nm
Content of silica particles in dispersion: 30% by weight 92.0 0.11 10.93 64.29 300.53 Comparative Example 6 Silica Dispersion A (SSD_330T, Ranco)
Average particle size: 10nm
Content of silica particles in dispersion: 30% by weight 92 3.04 300.56 61.36 300.53 Comparative Example 7 Silica Dispersion A (SSD_330T, Ranco)
Average particle size: 10nm
Content of silica particles in dispersion: 30% by weight 8.93 0.27 26.53 64.13 358.68

<Measurement example>

The following measurements were performed on the polyimide-based films prepared in Examples 1 to 7 and Comparative Examples 1 to 7.

1) Measurement of true density ratio (DR) to density gradient pipe density

The true density and density gradient tube density of the polyimide-based film were measured as follows, and the measured true density and density gradient tube density were calculated according to Equation 1 below to calculate the true density ratio to the density gradient tube density of the polyimide-based film. (DR) was calculated.

<Equation 1>

DR = true density/density gradient pipe density

(1) True density measurement

A polyimide film (100 ⁾ specimen ( ¹⁰ Fill the freeze grinder (Japan Analytical Industry, JFC-300) with more than 2/3 of liquid nitrogen, combine the sample holder containing the cut specimen with the freeze grinder, close the chamber, and pre-cool for 15 minutes using the freeze grinder. The specimens were pulverized for more than 15 minutes. The true density of the pulverized film (100) specimen was measured seven times using Micromeritics' AccuPyc 1340 Pycnometer equipment (using helium gas). The true density of the polyimide-based film 100 was calculated by excluding the highest and lowest values among the measured true density values of the film 100 and calculating the average of the remaining true density values.

(2) Density gradient pipe density measurement

According to the standard ASTM D1505, the density gradient tube density of the polyimide-based film 100 was measured using a density gradient tube.

2) Measurement of particle volume concentration (PVC)

After measuring the volume of the filler (V ₁ ) and the volume of the matrix (V ₂ ) of the polyimide-based film, the particle volume concentration (PVC) of the polyimide-based film was calculated according to Equation 2 below.

<Equation 2>

PVC(%) = [V ₁ / (V ₁ + V ₂ )]*100

In Equation 2, V ₁ is the volume of the filler, and V ₂ is the volume of the matrix.

The volume of the filler (V ₁ ) can be calculated by dividing the mass of the filler by the density. Specifically, the volume (V ₁ ) of the filler can be calculated by measuring the mass and density of the filler included in the film 100, respectively. For example, the mass of the filler can be known by measuring the weight of the filler added when manufacturing the film 100. The density of the filler can be measured using the true density measurement method or the density gradient pipe density measurement method described above.

The volume of the matrix (V ₂ ) can be calculated by dividing the mass of the matrix by the density. Specifically, the volume (V ₂ ) of the matrix can be calculated by measuring the mass and density of the matrix included in the film 100, respectively. For example, the mass of the matrix can be known by measuring the weight of the matrix added when manufacturing the film 100. The density of the matrix can be measured using the true density measurement method or the density gradient pipe density measurement method described above.

3) Young's modulus and elongation: According to the ASTM D885 method, the Young's modulus and elongation of the polyimide film were measured using an Instron universal tensile tester.

4) Indentation hardness: The manufactured polyimide film was cut into 2cm . A total of 7 measurements were made, the highest and lowest values were excluded, and the average of the remaining HV values was calculated to calculate the indentation hardness of the polyimide-based film.

5) Optical transmittance (%): The average optical transmittance was measured at a wavelength of 360 to 740 nm using a spectrophotometer (CM-3700D, KONICA MINOLTA) according to the standard ASTM E313.

6) Yellowness: Yellowness was measured using a Spectrophotometer (CM-3700D, KONICA MINOLTA) according to the standard ASTM E313.

7) Haze: The manufactured polyimide film was cut into 50 mm Х 50 mm and measured 5 times according to ASTM D1003 using MURAKAMI's haze meter (model name: HM-150), and the average value was taken as the haze value. .

The measurement results are shown in Tables 2 and 3 below.

division True Density Density Gradient Pipe Density Density Gradient True Density Ratio (DR) to Pipe Density Particle Volume Concentration (PVC)
(%) Example 1 1.615 1.475 1.095 7.4 Example 2 1.719 1.608 1.069 27.92 Example 3 1.782 1.694 1.052 37.07 Example 4 1.619 1.480 1.094 7.4 Example 5 1.692 1.573 1.076 23.6 Example 6 1.718 1.607 1.069 27.92 Example 7 1.631 1.571 1.038 23.58 Comparative Example 1 1.880 1.702 1.105 46.8 Comparative Example 2 1.619 1.460 1.109 7.4 Comparative Example 3 1.617 1.461 1.107 7.4 Comparative Example 4 1.618 1.459 1.109 7.4 Comparative Example 5 1.629 1.47 1.108 23.58 Comparative Example 6 1.63 1.47 1.109 23.58 Comparative Example 7 1.604 1.45 1.106 2.91

division Young's modulus
(Young’s modulus)
(GPa) elongation
(%) Indentation hardness light transmittance
(%) yellowness Haze Example 1 5.1 28 46 89.6 2.7 0.2 Example 2 5.7 25 51 90.4 2.3 0.2 Example 3 5.8 20 53 90.6 2.1 0.3 Example 4 5.1 17 46 89.7 2.8 0.3 Example 5 5.5 16 49 90.1 2.5 0.3 Example 6 5.7 24 52 90.5 2.2 0.2 Example 7 5.6 17 50 90.4 2.2 0.3 Comparative Example 1 4.9 7 41 88.8 3.1 0.6 Comparative Example 2 4.9 10 41 88.5 3.2 0.8 Comparative Example 3 4.9 13 40 88.3 3.5 1.2 Comparative Example 4 4.7 11 41 88.2 3.9 1.8 Comparative Example 5 4.8 14 42 88.7 3.2 0.8 Comparative Example 6 4.9 13 41 88.7 3.1 0.8 Comparative Example 7 4.7 14 43 88.6 3.4 0.7

As disclosed in the measurement results in Tables 2 and 3, the polyimide-based film 100 according to an embodiment of the present invention has a true density ratio (DR) to the density gradient pipe density of 1.10 or less, and Young's modulus, elongation, and indentation It can be confirmed that not only are the mechanical properties such as hardness excellent, but the optical properties are also excellent due to excellent light transmittance, low yellowness, and low haze. However, Comparative Example 1 shows that the filler content is high relative to the total weight of the polyimide film. The content exceeds 50% by weight, the true density ratio (DR) to the density gradient pipe density exceeds 1.10, the particle volume concentration (PVC) exceeds 38%, and the Young's modulus of the polyimide film is less than 5.0 GPa. , elongation was less than 15%, indentation hardness was less than 45%, and yellowness was more than 3.0.

Comparative Example 2 was a polyimide resin powder mixed with a filler dispersion without being divided into first and second contents, and the true density ratio (DR) to the density gradient tube density exceeded 1.10, and the polyimide film Young's modulus was less than 5.0 GPa, elongation was less than 15%, indentation hardness was less than 45%, and yellowness was more than 3.0.

In Comparative Example 3, the polyimide resin powder was mixed with the filler dispersion liquid without dividing into the first content and the second content, and the average particle diameter of the filler was greater than 50 nm, and the true density ratio (DR) to the density gradient tube density was ) exceeded 1.10, and the Young's modulus of the polyimide film was less than 5.0 GPa, elongation was less than 15%, indentation hardness was less than 45%, yellowness was more than 3.0, and haze was more than 1%.

In Comparative Example 4, the average particle diameter of the filler was more than 50 nm, the true density ratio (DR) to the density gradient tube density was more than 1.10, the Young's modulus of the polyimide film was less than 5.0 GPa, the elongation was less than 15%, and the press fit. Hardness was less than 45%, yellowness was more than 3.0, and haze was more than 1%.

In Comparative Example 5, the first content of polyimide-based resin powder relative to the filler weight was less than 0.5%, the true density ratio (DR) to the density gradient pipe density exceeded 1.10, and the Young's modulus of the polyimide-based film was 5.0 GPa. The elongation was less than 15%, the indentation hardness was less than 45%, and the yellowness was more than 3.0.

In Comparative Example 6, the first content of polyimide-based resin powder relative to the filler weight was more than 10%, the true density ratio (DR) to the density gradient pipe density exceeded 1.10, and the Young's modulus of the polyimide-based film was 5.0. Less than GPa, elongation less than 15%, indentation hardness less than 45%, and yellowness greater than 3.0.

In Comparative Example 7, the filler content was less than 5% by weight based on the total weight of the polyimide film, the true density ratio (DR) to the density gradient pipe density exceeded 1.10, and the Young's modulus of the polyimide film was 5.0. Less than GPa, elongation less than 15%, indentation hardness less than 45%, and yellowness greater than 3.0.

100: polyimide-based film
110: Polyimide-based matrix
120: filler
200: display device
501: display panel

Claims (13)

polyimide-based matrix; and
It includes a filler dispersed in the polyimide-based matrix,
The polyimide-based matrix includes any one of polyimide resin and polyamide-imide resin,
The average particle diameter of the filler is 5 to 50 nm,
The content of the filler is 5 to 50% by weight based on the total weight of the polyimide film,
A polyimide-based film having a true density ratio (DR) to density gradient tube density of 1.10 or less:
The true density ratio (Density Ratio, DR) to the density gradient pipe density is calculated using Equation 1 below.
<Equation 1>
Density Ratio (DR) = true density / density gradient pipe density According to paragraph 1,
Polyimide-based film, having a particle volume concentration (PVC) of 5 to 38%:
The particle volume concentration (PVC) is calculated using Equation 2 below.
<Equation 2>
PVC(%) = [V ₁ / (V ₁ + V ₂ )]*100
In Equation 2, V ₁ is the volume of the filler, and V ₂ is the volume of the matrix. According to paragraph 1,
The filler is a polyimide-based film containing silica (SiO ₂ ). According to paragraph 3,
A polyimide-based film in which at least a portion of the silica (SiO ₂ ) is surface-treated with an organic compound having an alkoxy group. delete delete According to paragraph 1,
A polyimide-based film having a Young's Modulus of 5.0 GPa or more. According to paragraph 1,
A polyimide-based film having an elongation of 15% or more. According to paragraph 1,
A polyimide-based film having an indentation hardness of 45 or more. According to paragraph 1,
A polyimide-based film having a yellowness of 3 or less. According to paragraph 1,
A polyimide-based film having a haze of 1% or less. According to paragraph 1,
A polyimide-based film having a light transmittance of 85% or more. display panel; and
The polyimide-based film according to any one of claims 1 to 4 and 7 to 12, disposed on the display panel;
Including a display device.

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