KR20160088751A - Protective film and method for fabricating display device using same - Google Patents

Abstract

Disclosed are a protective film for a display panel which can effectively manufacture a display device by easily detecting a defect of a display panel and a polarizing plate; and a method for manufacturing a display device using the same. The method for manufacturing a display device comprises the following steps: (1) arranging a protective film on a display panel; (2) arranging a polarizing plate on the protective film; (3) detecting the display panel and the polarizing plate; (4) removing the protective film; and (5) attaching the polarizing plate to the display panel. The protective film includes polyester, and has an in-plane phase difference of more than or equal to 3000 nm.

Description

PROTECTIVE FILM AND METHOD FOR FABRICATING DISPLAY DEVICE USING SAME FIELD OF THE INVENTION [0001]

This embodiment relates to a protective film and a method for manufacturing a display device using the same.

2. Description of the Related Art Liquid crystal display devices are widely used every year as image display devices with low power consumption and space saving. Conventionally, the liquid crystal display device has a great drawback that the viewing angle dependency of the display image is large. However, a wide viewing angle liquid crystal mode such as VA (vertical alignment) mode and IPS (in plane switching) mode is put to practical use, Demand for liquid crystal displays is also rapidly expanding in demanding markets.

The basic structure of the liquid crystal display device is that polarizing plates are formed on both sides of the liquid crystal cell. The polarizing plate transmits only the light of the polarization plane in a certain direction, and the performance of the liquid crystal display greatly depends on the performance of the polarizing plate. The VA mode and the IPS mode are displayed in black (i.e. normally black) when the interelectrode voltage of the liquid crystal cell is 0, and the light absorption axes of the polarizers on both sides of the liquid crystal cell are arranged to be orthogonal to each other. The non-polarized light emitted from the light source transmits only polarized light in a predetermined direction on the polarizing plate on the light source side and transmits the polarized light without changing its polarization state when it passes through the liquid crystal cell and the light absorption axis is orthogonal to the polarizing plate on the light source side And is absorbed by the disposed polarizer on the viewer side. Thus, black display can be realized.

A polarizing plate of a liquid crystal display has a polarizer composed of a polyvinyl alcohol film or the like in which iodine or dye is adsorbed and oriented, and a transparent protective film is attached to both sides of the polarizing plate. As the polarizing plate protective film, a cellulose acetate-based polarizing plate protective film typified by cellulose triacetate (TAC) is widely used because of its high transparency and easy adhesion to polyvinyl alcohol used for polarizers come.

Korean Patent Publication No. 2003-0074126

Embodiments provide a protective film for a display panel which can easily detect defects of a display panel and a polarizing plate and can effectively manufacture a display device and a method of manufacturing a display device using the same.

A manufacturing method of a display device according to an embodiment includes (1) disposing a protective film on a display panel; (2) disposing a polarizer on the protective film; (3) inspecting the display panel and the polarizer; (4) removing the protective film; And (5) attaching the polarizing plate to the display panel, wherein the protective film includes polyester and has an in-plane retardation of 3,000 nm or more.

The protective film for a display panel according to an embodiment includes a polyester film having an in-plane retardation of 3,000 nm or more, wherein the film is divided into a plurality of grid areas having a rectangular planar shape having a side length of 0.3 to 2 cm Wherein at least 90% of the grid regions have an orientation direction that is within ± 5 ° with respect to the orientation direction of the film, wherein the orientation direction of the grid region is defined as an average orientation direction of the polymer contained in the grid region, The orientation direction of the film is defined as the average orientation direction of the grid areas.

The protective film according to this embodiment can be adhered to a display panel such as a liquid crystal panel or an organic field display panel to protect the display panel.

Furthermore, after the polarizing plate is disposed on the protective film adhered to the display panel, the display panel and the polarizing plate can be effectively inspected while protecting the display panel with the protective film.

At this time, since the protective film has an in-plane retardation of 3,000 nm or more, even if it is disposed between the display panel and the polarizer, no noise of rainbow colors is generated.

Therefore, the display device can be easily manufactured using the protective film according to the embodiment.

1 is a plan view showing a protective film according to an embodiment.
2 and 3 are views showing a process of measuring the alignment direction of the protective film.
4 is a view showing the orientation direction of the protective film and the orientation direction of the grid area.
5 is a view illustrating a process of manufacturing a protective film according to one embodiment.
6 is a view illustrating a process of manufacturing a protective film according to another embodiment.
7 and 8 are views illustrating a process of manufacturing a display device according to an embodiment.

In the description of the present invention, in the case where each plate, film or layer is described as being formed "on" or "under" of each plate, film or layer, quot; on "and" under " include both being formed directly or indirectly through other elements. In addition, the upper or lower reference of each component is described with reference to the drawings. The size of each component in the drawings may be exaggerated for the sake of explanation and does not mean the size actually applied.

1 to 8, a protective film 100, 110, or 120 according to an embodiment is provided, and a display device can be manufactured using the protective film.

FIG. 1 is a plan view showing a protective film, and FIGS. 2 and 3 show a process of measuring the alignment direction of the protective film.

The protective film 100 has a high retardation. More specifically, the in-plane retardation of the protective film may be about 3,000 nm or more. More specifically, the in-plane retardation of the protective film may be about 5,000 nm or more. More specifically, the in-plane retardation of the protective film may be about 10,000 nm or more. More specifically, the in-plane retardation of the protective film may be about 20,000 nm or more.

The in-plane retardation is a measure indicating the optical isotropy or anisotropy of a film, and can be calculated, for example, by the following equation 1:

[Equation 1]

Re = (nx-ny) Xd

In the above equation, nx is the in-plane refractive index in the X-axis direction, ny is the refractive index in the Y-axis direction, and d is the thickness of the film.

Here, the X-axis is a direction in which the in-plane refractive index of the film is maximized, and the Y-axis is a direction perpendicular to the X-axis.

The protective film may be a uniaxially stretched film. More specifically, the protective film may be a uniaxially stretched polyester film. More specifically, the protective film may be a uniaxially stretched polyethylene terephthalate film.

That is, the protective film may be stretched in one direction and not elongated in the other direction or may be slightly stretched. For example, the protective film may be stretched at least about 2.5 times in the first direction and about 1.5 times or less in the second direction perpendicular to the first direction. More specifically, the protective film may be stretched about 3.0 times or more in the first direction and about 1.3 times or less in the second direction perpendicular to the first direction. More specifically, the protective film may be stretched at least about 3.5 times in the first direction and about 1.2 times or less in the second direction perpendicular to the first direction. The protective film may be a film stretched to about 6 times or less in the first direction.

Further, the protective film may have a uniform orientation direction as a whole.

The orientation direction (orientation axis) of the protective film may be substantially the same as or coincident with the stretching direction (stretching axis) of the protective film.

Referring to FIG. 1, the protective film 100 may be divided into a plurality of grid regions G having a rectangular planar shape. More specifically, the protective film 100 may be divided into a plurality of grid regions G having a rectangular planar shape with one side of 0.3 to 2 cm in length.

2 and 3, the orientation direction of the grid area G may be determined by the following method.

First, the protective film 100 is cut into the respective grid areas G and disposed between the upper polarizer 105 and the lower polarizer 106. At this time, the protective film 100 and the polarizing plates 105 and 106 are arranged in parallel and spaced apart from each other.

At this time, the polarization axis (transmission axis) of the upper polarizer 105 and the polarization axis of the lower polarizer 106 are perpendicular to each other.

Light is irradiated through the lower polarizer 106 and light polarized and transmitted through the lower polarizer 106 is irradiated to each of the grid areas G (L1: incident on the protective film). Thereafter, the light (L2: protective film transmitted light) transmitted through each of the grid areas G is incident on the upper polarizer 105.

At this time, each of the grid areas G rotates about a rotation axis substantially perpendicular to the polarizing plates 105 and 106 and the protective film 100.

In accordance with the rotation, the intensity of light transmitted through the upper polarizer 105 is measured (L3: polarized plate transmitted light). At this time, when the intensity of the light transmitted through the upper polarizer 105 is the smallest, the polarization axis (transmission axis) of one of the polarizers 105 and 106 can be the alignment direction of each grid area G. In this case, since the alignment direction of the grid area G is roughly determined, it can be determined that the polarization axis of the polarizing plate 105, 106 coincides with the alignment direction of the grid area G, have.

Alternatively, the average orientation direction of the polymer contained in each of the grid regions G may be determined by X-ray diffraction measurement.

The orientation direction of the protective film 100 may be defined as an average orientation direction of the grid areas G. [ That is, the orientation direction of the protective film 100 may be derived by averaging the orientation directions of the grid regions G.

The deviation of the orientation direction of the grid areas G is preferably small, and thus the orientation direction of the grid areas G may be substantially constant. When the deviation of the alignment direction of the grid areas G is minimized, the protective film 100 may have uniform optical characteristics as a whole.

Fig. 4 shows a diagram showing the orientation direction of the protective film and the orientation direction of the grid area. Referring to FIG. 4, the orientation direction of each of the grid areas G may be within a range of ± θ with respect to the orientation direction of the protective film 100. Preferably, the orientation direction of each of the grid areas G may be in the range of 0 to 5 deg., Preferably 0 to 2 deg., Based on the orientation direction of the protective film 100. [

The protective film of the present invention may have an orientation direction in which at least 90% of the grid areas G are within ± 5 ° with respect to the orientation direction of the protective film 100, 90% or more is within ± 2 ° with respect to the orientation direction of the protective film 100. More preferably, 95% or more of the grid areas G are oriented in the orientation of the protective film 100 Direction, and preferably more than 97% of the grid areas G have an orientation direction that is within ± 2 ° with respect to the orientation direction of the protective film 100 . More preferably, 99% or more of the grid areas G may have an orientation direction within ± 2 ° with respect to the orientation direction of the protective film 100.

The protective film 100 includes a polymer. Examples of the polymer include polyester, polyvinyl chloride, and polyimide. The protective film 100 may preferably be a polyester resin, and the polyester may be an aromatic polyester .

The polymer may include a diol component and a dicarboxylic acid component. More specifically, the polyester resin may consist entirely of the diol component and the dicarboxylic acid component. More specifically, the polyester resin may contain about 95 mol% or more of the diol component and the dicarboxylic acid component.

The polyester resin may be formed by polymerizing the diol component and the dicarboxylic acid component after the transesterification reaction.

Specific examples of the diol component include ethylene glycol, 1,4-cyclohexanedimethanol, 1,3-propanediol, 1,2-octanediol, 1,3-octanediol, 2,3 Butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol) 1,3-propanediol, 2,2-diethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 3- 1,5-pentanediol, and mixtures thereof.

The dicarboxylic acid component may be an aromatic dicarboxylic acid such as terephthalic acid, dimethyl terephthalate, isophthalic acid, naphthalene dicarboxylic acid, and orthophthalic acid; Aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and decanedicarboxylic acid; Alicyclic dicarboxylic acid; And their esterified products can be used alone or in combination of two or more.

More specifically, the polymer may be polyethylene terephthalate. The polyethylene terephthalate may contain 75 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, and still more preferably 95 mol% or more of ethylene terephthalate as monomer units . As described above, when the polyethylene terephthalate contains ethylene terephthalate in an amount of 75 mol% or more as monomer units, the polyester may have crystallinity. Therefore, when the protective film 100 includes polyethylene terephthalate, the polyethylene terephthalate has crystallinity, and the crystal plane of the polyethylene terephthalate may have orientation in one direction.

The protective film 100 may be substantially transparent. The haze of the protective film 100 may be about 5% or less, preferably about 3% or less, and more preferably about 2% or less.

The thickness of the protective film 100 may be 10 탆 to 1 탆, preferably 20 탆 to 700 탆, and more preferably 25 탆 to 300 탆. According to one embodiment, when the protective film includes a polyester resin, the thickness of the protective film 100 may be 30 μm to 250 μm.

The protective film 100 may include additional layers as required.

For example, the protective film 100 may further include an adhesive layer coated on at least one surface thereof.

FIGS. 5 and 6 show processes for manufacturing a protective film according to an embodiment of the present invention.

The protective film 100 according to the present embodiment includes a step of extruding a polyester resin; Casting the extruded polyester resin to form an unstretched film (101); And stretching the unstretched film (101) three to five times in one direction to form an oriented protective film (100).

Here, the protective film 100 is divided into a plurality of grid areas G having a rectangular planar shape with one side of 0.3 to 2 cm in length, and 90% or more of the grid areas G are divided into the protective film The orientation direction of the grid region G is defined as the average orientation direction of the polymer contained in the grid region G and the orientation direction of the protective film 100 are defined as an average alignment direction of the grid areas G. [

Referring to Fig. 5, first, the polyester resin is melted and discharged through the T-die 10, and the resin discharged to the casting roll 20 is coated to form an unstretched film 101. [ The unstretched film 101 may be formed by cooling by the casting roll 20. The surface temperature of the casting roll 20 is preferably in the range of Tg-100 ° C to Tg + 20 ° C, preferably (Tg-70) ° C to (Tg-5) ° C . ≪ / RTI >

Next, the unstretched film 101 is stretched in the longitudinal direction by the peripheral speed difference between the first stretching roll 31 and the second stretching roll 32. Accordingly, the protective film 100 is formed. At this time, the unstretched film 101 may be stretched only in the longitudinal direction, and may not be stretched in the width direction. That is, the unstretched film 101 may not be stretched in the width direction or may be stretched to about 1.2 times or less even if stretched.

Alternatively, as shown in Fig. 6, the unstretched film 101 may be stretched only in the width W direction, and may not be stretched in the length direction. That is, the unstretched film 101 can be stretched to about 1.2 times or less even if it is not stretched in the longitudinal direction or stretched.

When the stretching is performed, the stretching ratio of the undrawn film 101 may be 2.5 to 6 times, preferably 3 to 5 times, and more preferably 3.5 to 4.5 times . If the unstretched film 101 is stretched to 6 times or less, fracture may not occur. Further, when the unstretched film 101 is stretched 2.5 times or more, the polymer contained in the unstretched film 101 can be sufficiently oriented.

The stretching process may be carried out in an oven. The stretching temperature in such a stretching process may be in the range of Tg to Tg + 40 占 폚 with respect to the glass transition temperature (Tg) of the polyester resin, preferably from Tg to Tg + 20 Lt; 0 > C. If the stretching temperature of the protective film 100 is less than Tg, stretching becomes difficult. If the stretching temperature exceeds Tg + 40 占 폚, the stress required for stretching becomes extremely low, Is insufficient and it is difficult to exhibit desired physical properties of the protective film, which is not preferable.

The stretching speed in the stretching step may be 200% / min to 500% / min.

When the stretching speed is 200% / min or more, the protective film 100 is preferably uniformly formed in its entirety, and if the stretching speed is 500% / min or less, Can be produced.

Next, the stretched protective film 100 is heated to a temperature higher than the Tg and lower than the Tm-15 ° C with respect to the glass transition temperature (Tg) and the melting point (Tm) of the polyester resin contained in the protective film 100 (Heat fixation) in the heat treatment temperature range, and the range of the heat treatment temperature may be 160 ° C to 240 ° C. More specifically, when the protective film 100 is made of polyethylene terephthalate, the protective film 100 may be heat-treated at a temperature of about 170 ° C to 190 ° C. The heat treatment process may be conducted for about 30 seconds to about 5 minutes.

Also, in the heat treatment process, the protective film 100 may relax at a relaxation rate of about 0% to about 3%.

Thereafter, the heat-treated protective film 100 may be cooled. The cooling temperature may be from about 40 째 C to about 90 째 C, more specifically from about 50 째 C to about 70 째 C. The cooling process may be conducted for about 10 seconds to about 1 minute.

The width W of the protective film 100 thus formed may be 0.5 to 5 m, preferably 1 to 3 m.

The polymer of the protective film 100 is uniformly oriented as a whole. Accordingly, the protective film according to the embodiment can have overall uniform optical characteristics.

The orientation direction of the protective film 100 may correspond to the width direction or the longitudinal direction of the protective film 100.

In particular, the protective film 100 may have a uniform orientation direction in the width direction.

Then, the protective film 100 is wound by the winding roll 40.

If necessary, a slip layer may be formed on the upper and lower surfaces of the protective film 100 through a post-process.

The protective film 100 formed in the roll shape can be suitably cut and used.

The protective film may be used as a protective film for a display panel such as a liquid crystal display panel or an organic electric field display panel. Accordingly, the protective film can be applied to the manufacture of a display device such as a liquid crystal display device, an organic field display device, or the like. Specifically, the protective film can be used as a protective film of a display panel at the time of inspection of a display panel and a polarizing plate which are performed during manufacturing of the display device.

A manufacturing method of a display device according to an embodiment includes (1) disposing a protective film on a display panel; (2) disposing a polarizer on the protective film; (3) inspecting the display panel and the polarizer; (4) removing the protective film; And (5) attaching the polarizing plate to the display panel.

In the step (1), an adhesive layer may be disposed between the display panel and the protective film.

In the step (2), the polarizing plate may be arranged so that the alignment direction of the protective film corresponds to the polarization direction (polarization axis) of the polarizing plate.

In the step (3), the inspection is performed while the display panel is protected by the protective film.

In the step (4), the protective film may be removed, and the adhesive layer may remain. Alternatively, the protective film and the adhesive layer may be simultaneously removed.

In the step (5), the polarizing plate may be attached to the display panel.

The display panel may be a liquid crystal display panel or an organic field display panel.

The protective film may be the same as the protective film described above

7 and 8, the liquid crystal display according to the embodiment can be manufactured by the following method.

The first protective film 110 and the second protective film 120 are attached to the lower surface and the upper surface of the liquid crystal display panel 510 through the adhesive layers 210 and 220 as shown in FIG.

A lower polarizer plate 520 and an upper polarizer plate 530 are disposed below the first protective film 110 and on the second protective film 120, respectively. That is, the lower polarizer 520 and the upper polarizer 530 sandwich a laminate of the liquid crystal display panel 510, the first protective film 110, and the second protective film 120.

At this time, the first protective film 110 is interposed between the lower polarizer 520 and the liquid crystal display panel 510 to protect the liquid crystal display panel 510. The second protective film 120 is interposed between the upper polarizer 530 and the liquid crystal display panel 510 to protect the liquid crystal display panel 510.

The liquid crystal display panel 510 includes a color filter substrate, a liquid crystal layer, and a TFT substrate, wherein the TFT substrate and the color filter substrate are opposed to each other.

The TFT substrate includes a plurality of pixel electrodes corresponding to each pixel, thin film transistors connected to the pixel electrodes, a plurality of gate lines for applying driving signals to the thin film transistors, And a plurality of data lines for applying a data signal to the pixel electrodes.

The color filter substrate includes a plurality of color filters corresponding to respective pixels. The color filters may filter transmitted light to achieve red, green, and blue, respectively. In addition, the color filter substrate may include a common electrode facing the pixel electrodes.

The liquid crystal layer is interposed between the TFT substrate and the color filter substrate. The liquid crystal layer may be driven by the TFT substrate, and the liquid crystal layer may be driven by an electric field formed between the pixel electrodes and the common electrode. The liquid crystal layer can adjust the polarization direction of the light transmitted through the lower polarizer 520. That is, the TFT substrate can control a potential difference applied between the pixel electrodes and the common electrode in pixel units. Accordingly, the liquid crystal layer can be driven to have different optical characteristics on a pixel-by-pixel basis.

Light is then incident on the lower polarizer 520 from a light source 600 such as a backlight. The incident light sequentially passes through the lower polarizer 520, the first protective film 110, the liquid crystal display panel 510, the second protective film 120, and the upper polarizer 530, and is displayed as an image. The displayed image is visually inspected to determine whether the liquid crystal display panel 510, the upper polarizer 530, and the lower polarizer 520 are defective.

As the first protective film 110 and the second protective film 120, the protective film 100 described above may be used.

As described above, the protective film may be a uniaxially stretched film. Accordingly, the first protective film 110 and the second protective film 120 have a high in-plane retardation.

At this time, the alignment direction (alignment axis) of the first protective film 110 corresponds to the polarization direction (polarization axis) of the lower polarizer 520. That is, the alignment direction of the first protective film 110 may be substantially the same as the polarization direction of the lower polarizer 520. For example, the angle between the alignment direction of the first protective film 110 and the polarization direction of the lower polarizer 520 may be within about 3 degrees.

In addition, the alignment direction (alignment axis) of the second protective film 120 corresponds to the polarization direction (polarization axis) of the upper polarizer 530. That is, the alignment direction of the second protective film 120 may be substantially the same as the polarization direction of the upper polarizer 530. For example, the angle between the alignment direction of the second protective film 120 and the polarization direction of the upper polarizer 530 may be within about 3 degrees.

Accordingly, the distortion of the display image generated by the first protective film 110 and the second protective film 120 can be minimized. In particular, since the polarizing directions of the protective film and the polarizing plate adjacent to each other coincide with each other, distortion due to rainbow stains caused by the protective film can be minimized.

In particular, since the first protective film 110 and the second protective film 120 have a uniform alignment direction without any variation in the total area, the above-described distortion can be minimized.

Referring to FIG. 8, after the inspection is completed, the first protective film 110 and the second protective film 120 are removed. At this time, the adhesive layers 210 and 220 remain.

The lower polarizer 520 and the upper polarizer 530 are attached to the liquid crystal display panel 510 through the adhesive layers 210 and 220 so that the liquid crystal display according to the embodiment can be manufactured. have.

Further, although not shown in the figure, an organic field display device can be manufactured as follows.

First, a protective film is attached to the organic EL display panel by an adhesive layer, and a polarizing plate is disposed on the protective film.

Thereafter, an image is emitted from the organic light emitting display panel, and the emitted image is sequentially transmitted through the protective film and the polarizing plate.

The displayed image may be inspected by a naked eye or the like to determine whether the organic electroluminescent display panel and the polarizing plate are defective or not.

As described above, the protective film is adhered to the organic electroluminescent display panel to protect the organic electroluminescent display panel during the inspection.

Thereafter, the protective film is removed, and the polarizing plate may be attached to the organic EL display panel.

The alignment direction of the protective film and the polarization direction (polarization axis) of the polarizing plate can substantially coincide with each other, as in the liquid crystal display device described above.

Particularly, since the protective film has an in-plane retardation of 3,000 nm or more, even when disposed between the display panel and the polarizing plate, no noise of rainbow colors is generated.

Therefore, the protective film according to the embodiment can effectively inspect the display panel and the polarizing plate while protecting the display panel.

Therefore, the protective film according to the embodiment and the method for manufacturing the display device using the same can easily provide the display device.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are illustrative of the present invention, and the present invention is not limited to the following examples.

Example 1

Manganese acetate as an ester exchange catalyst to dimethyl terephthalate and ethylene glycol as an ester exchange catalyst, antimony trioxide as a polymerization catalyst and phosphorous acid as a stabilizer are added and then transesterification and polycondensation reaction are carried out to obtain an o- 0.65 dl / g of polyethylene terephthalate (PET) pellet A was prepared.

Then, the produced PET pellets A were dried at 170 DEG C for 3 hours, fed to a hopper of an extruder, melted at a melting temperature of 290 DEG C, filtered, filtered through a T die, To obtain a single layer unoriented film having a thickness of 320 탆.

The obtained unstretched film was held by a tenter clip and stretched at a stretching speed of about 4.0 times at a stretching speed of 300% / minute at 85 캜 in the width direction. Thereafter, the stretched film was heat-treated at 180 캜 for about one minute. Thereafter, the heat-treated film was cooled at a temperature of about 80 캜 for about 30 seconds.

Then, of the heat-treated films, the portions gripped by the tenter clips were cut out to produce a protective film having a thickness of 50 mu m and a width of 1.5 mu m.

Example  2 to 5

A protective film was prepared in the same manner as in Example 1, except that the stretching speed, the stretching ratio, the heat treatment temperature, the cooling temperature, or the relaxation rate were changed as shown in Table 1 below.

Comparative Examples 1 to 3

A protective film was prepared in the same manner as in Example 1, except that the stretching speed, the stretching ratio, the heat treatment temperature or the thickness were changed as shown in Table 1 below.

division Elongation speed
(%/minute) Transverse stretching ratio
(ship) Mystery mystery
(ship) Heat treatment temperature
(° C) thickness
(탆) Example 1 295 4.07 times 1.2 195 50 Example 2 492 4.07 times 1.2 195 75 Example 3 295 4.07 times 1.2 195 100 Example 4 295 4.07 times 1.2 195 150 Example 5 492 4.17 times 1.2 190 150 Comparative Example 1 492 Twice 1.2 230 150 Comparative Example 2 1,000 4.05 times 1.2 230 150 Comparative Example 3 295 4.13 times 3.2 230 55

Test Example 1: Orientation Direction

The protective films obtained in the above Examples and Comparative Examples were each cut to a length of 1 m, and the orientation directions of the respective protective films were measured.

First, each protective film 100 was divided into grid areas G having a size of 1 cm x 1 cm, and the orientation directions of the respective grid areas G were measured.

The orientation directions of the respective grid areas G were measured using two polarizing plates, as described above. That is, when light is transmitted through the upper polarizer plate, the alignment direction having the lowest luminance is defined as the alignment direction of each grid area G. At this time, MC-2903S or MCPD-3000 manufactured by Otsuka Co., Ltd. was used for measurement of luminance and the like.

Thereafter, the orientation direction of the protective film 100 was calculated by averaging the orientation directions of the grid regions G. FIG.

Test Example 2: Orientation uniformity

The ratio of the number of grid areas G having the orientation direction within the range of +/- 2 DEG with respect to the orientation direction of the protective film 100 among the total number of grid areas G of each protective film 100 is calculated as a percentage And the orientation uniformity was measured.

Test Example 3: Rainbow Color

The protective films obtained in the above Examples and Comparative Examples were respectively attached to both sides of a liquid crystal display panel (manufactured by LG Display Co., Ltd.). Thereafter, the polarizing plates were respectively arranged on the upper and lower surfaces of the laminate thus produced. At this time, the polarizing plate (polarizing axis) of the polarizing plate was aligned with the alignment direction of the protective film. Thereafter, light was irradiated to the lower polarizer using a backlight, and the occurrence of a rainbow color was visually inspected through the upper polarizer.

○: No rainbow color was observed.

Δ: Some rainbow colors were observed.

Ⅹ: Rainbow colors were observed in most areas.

Test Example 4: Heat shrinkage

The protective films obtained in the above Examples and Comparative Examples were heat-treated at a temperature of 150 ° C for 30 minutes, and the widths before and after the heat treatment were measured. The heat shrinkage ratios in the width direction were calculated according to the following equations:

Heat shrinkage ratio in the width direction (%) = (width before heat treatment - width after heat treatment) / width before heat treatment x 100

Test Example 5: In-plane retardation

The refractive index (nx, ny) and the refractive index (nz) in the thickness direction perpendicular to the protective films obtained in the above Examples and Comparative Examples were measured using Abbe's refractive index meter (NAR-4T manufactured by Atago Co., ), And the absolute value (| nx-ny |) of the refractive index difference of the biaxial axis was defined as anisotropy (? Nxy) of the refractive index. The thickness d (nm) of the film was measured using an electric micrometer (Millitron 1245D, manufactured by Pahrung Paste), and the unit was converted to nm. Plane retardation Re was determined from the product (? Nxy x d) of the anisotropy (? Nxy) of the refractive index and the thickness d (nm) of the film.

The results of the above test examples are summarized in Table 2 below.

division In-plane retardation (nm) Uniformity of orientation (%) Rainbow color Width direction heat shrinkage ratio Example 1 5250 95 O 1.1% Example 2 7275 95 O 0.8% Example 3 10000 95 O 0.8% Example 4 13950 99 O 0.0% Example 5 14700 97 O 0.8% Comparative Example 1 5800 85 × 0.4% Comparative Example 2 13600 86 △ 0.1% Comparative Example 3 1300 82 × 1.2%

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, It is to be understood that the invention may be practiced within the scope of the appended claims.

10: T-die 20: casting roll
31: first stretching roll 32: second stretching roll
40: coiling roll 100: protective film
101: Undrawn film 105: Upper polarizer plate
106: lower polarizer plate 110: first protective film
120: second protective film 210, 220: adhesive layer
510: liquid crystal display panel 520: lower polarizer plate
530: Upper polarizer 600: Light source
G: grid area W: width
L1: Protective film incident light L2: Protective film Transmitted light
L3: polarized plate transmitted light

Claims (12)

(1) disposing a protective film on a display panel;
(2) disposing a polarizer on the protective film;
(3) inspecting the display panel and the polarizer;
(4) removing the protective film; And
(5) attaching the polarizing plate to the display panel,
Wherein the protective film includes a polyester and has an in-plane retardation of 3,000 nm or more.
The method according to claim 1,
Wherein the protective film is divided into a plurality of grid areas having a rectangular planar shape with one side of 0.3 to 2 cm in length, and wherein at least 90% of the grid areas are within ± 5 [deg.] With respect to the orientation direction of the protective film Direction,
In this case, the orientation direction of the grid region is defined as an average orientation direction of the polymer included in the grid region, and the orientation direction of the protective film is defined as an average orientation direction of the grid regions.
A method of manufacturing a display device.
3. The method of claim 2,
In the step (2), the polarizing plate is arranged so that the alignment direction of the protective film and the polarization direction of the polarizing plate correspond to each other.
The method according to claim 1,
In step (1), an adhesive layer is disposed between the display panel and the protective film,
Wherein in step (5), the polarizing plate is attached to the display panel through the adhesive layer.
3. The method of claim 2,
Wherein the in-plane retardation of the protective film is 5,000 nm or more.
6. The method of claim 5,
Wherein the in-plane retardation of the protective film is 10,000 nm or more.
The method according to claim 6,
Wherein the in-plane retardation of the protective film is 20,000 nm or more.
The method according to claim 1,
Wherein the display panel is a liquid crystal display panel or an organic field display panel.
The method according to claim 1,
Wherein the protective film is a uniaxially stretched polyester film.
As a film containing a polyester and having an in-plane retardation of 3,000 nm or more,
Wherein the film is divided into a plurality of grid areas having a rectangular planar shape with one side having a length of 0.3 to 2 cm and at least 90% of the grid areas having an orientation direction that is within ± 5 ° with respect to the orientation direction of the film And,
In this case, the orientation direction of the grid region is defined as an average orientation direction of the polymer contained in the grid region, and the orientation direction of the film is defined as an average orientation direction of the grid regions.
11. The method of claim 10,
Wherein at least 90% of the grid areas have an orientation direction that is within +/- 2 DEG from the orientation direction of the film.
11. The method of claim 10,
Wherein the display panel protective film further comprises an adhesive layer coated on at least one surface thereof.

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