KR20160088741A - Substrate film and display device comprising same - Google Patents

Abstract

A substrate film and a display device including the same are disclosed. The display device comprises: a display panel; and an image mode switching unit arranged on the display panel. The image mode switching unit includes: a first transparent electrode substrate arranged on the display panel; a liquid crystal layer arranged on the first transparent electrode substrate; and a second transparent electrode substrate arranged on the liquid crystal layer. The first transparent electrode substrate includes: a first substrate film arranged on the display panel; and a first transparent electrode on the first substrate film. The first substrate film contains polyester and has an in-plane phase difference of at least 3,000 nm.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate film,

This embodiment relates to a base film and a display device using the base film.

The stereoscopic image display device uses a stereoscopic technique according to the principle of binocular disparity. Conventional display devices for implementing a 3D image using such a stereoscopic image technique have traditionally adopted a spectacle method. The spectacle method realizes a stereoscopic image by using polarizing glasses or liquid crystal shutter glasses to display the right and left parallax images in a direct view type display device or a projector by changing the polarization directions of the parallax images in a time division manner.

On the other hand, an autostereoscopic technique without glasses has been developed recently. In the glasses-free system, optical components such as a parallax barrier and a lenticular lens for separating the optical axis of the right and left parallax images are installed in front of or behind the display screen to realize a stereoscopic image.

As one example of the non-eyeglass system, a method using a lenticular lens is to separate a right-eye image and a left-eye image by a lenticular lens, thereby realizing a three-dimensional stereoscopic image. Since the method using the lenticular lens can not turn on / off the optical separation of the lens, it is possible to implement only the three-dimensional stereoscopic image and it is impossible to convert the three-dimensional stereoscopic image and the two-dimensional stereoscopic image. In order to solve the drawbacks of such a lenticular lens, a lenticular lens capable of switching a 3D / 2D image by implementing a lenticular lens by electrically controlling the refractive index of a liquid crystal has been proposed.

 Yoon Hyun Sik, et al., News & Information for Chemical Engineers, Vol. 31, No. 6, 2013, pp. 755-759.

The embodiments are directed to a stereoscopic image display device having improved image quality and a substrate film used therefor.

A display device according to an embodiment includes a display panel; And a video mode switching unit disposed on the display panel, wherein the video mode switching unit includes: a first transparent electrode substrate disposed on the display panel; A liquid crystal layer disposed on the first transparent electrode substrate; And a second transparent electrode substrate disposed on the liquid crystal layer, wherein the first transparent electrode substrate comprises: a first base film disposed on the display panel; And a first transparent electrode disposed on the first base film, wherein the first base film comprises a polyester and has an in-plane retardation of 3,000 nm or more.

The substrate film for a transparent electrode substrate according to an embodiment includes a polyester film having an in-plane retardation of 3,000 nm or more, wherein the film has a plurality of grid areas having a square planar shape with one side of 0.3 to 2 cm in length Wherein at least 90% of the grid areas have an orientation direction that is within ± 5 ° with respect to the orientation direction of the film, wherein the orientation direction of the grid area is defined as an average orientation direction of the polymer included in the grid area , The orientation direction of the film is defined as the average orientation direction of the grid areas.

The base film may be used for a transparent electrode substrate used in a video mode switching unit of a stereoscopic image display device. At this time, the orientation direction of the base film and the extending direction of the grooves for receiving the liquid crystal contained in the image mode switching unit may be substantially equal to each other.

The base film according to this embodiment has an in-plane retardation of about 3,000 nm or more. In particular, the base film comprises a uniformly oriented polymer as a whole. Accordingly, even when the base film forms the video mode switching section together with the liquid crystal, it does not show iridescence spots.

Therefore, the display device according to the present embodiment can prevent degradation of image quality such as rainbow color and realize an image of improved image quality.

FIG. 1 is a diagram illustrating a process of displaying a two-dimensional image according to an exemplary embodiment of the present invention.
2 is a diagram illustrating a process of displaying a three-dimensional image by a display apparatus according to an embodiment.
3 is a view showing a transparent electrode substrate according to an embodiment.
4 is a plan view showing a base film according to an embodiment.
5 and 6 are diagrams showing a process of measuring the alignment direction of the base film.
7 is a diagram showing the alignment direction of the base film and the alignment direction of the grid area.
8 is a view illustrating a process of manufacturing a base film according to an embodiment.
9 is a view showing a process of manufacturing a base film 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 9, a display device according to an embodiment includes a light source 600, a display panel 510, and a video mode switching unit 200.

The display panel 510 transmits light supplied from the light source 600 as it is or linearly polarizes the light by 90 degrees and supplies the light to the image mode switching unit 200 disposed at the upper side. For example, the display panel 510 may be a liquid crystal display panel having a liquid crystal layer 230 operating in a TN (twisted nematic) mode, and may be a vertical alignment (VA) mode, an in-plane switching ), A mode, and a fringe field switching (FFS) mode.

The display panel 510 may include a polarizing plate on one side or both sides, specifically, an upper polarizer and a lower polarizer in the case of a liquid crystal display panel.

The light source 600 may be a backlight. In addition, when the display panel 510 can emit light by itself, the light source 600 may be omitted.

In particular, the display panel 510 and the light source 600 may be replaced with organic electroluminescent display panels using an organic light emitting diode (OLED) or the like.

The image mode switching unit 200 is disposed in front of the display panel 510 and displays a 2D image by transmitting light as it is according to the polarization direction of the light incident from the display panel 510, And the path of light corresponding to the left eye image are separated to display a 3D image.

More specifically, in the 2D image mode in which an electric field is applied, the liquid crystal molecules are driven as shown in FIG. 1, and the liquid crystal molecules are raised. As a result, the refractive index difference between the liquid crystal molecules and the liquid crystal accommodating portion 231 is substantially eliminated. Accordingly, the light emitted from the display panel 510 passes through the image mode switching unit 200 as it is. Accordingly, the display device according to the embodiment can implement a 2D image.

Also, in the 3D image mode in which no electric field is applied, the liquid crystal molecules are not lifted as shown in FIG. 2 in the image mode switching unit 200. As a result, a difference in refractive index occurs between the liquid crystal molecules and the liquid crystal accommodating portion 231. Accordingly, the light emitted from the display panel 510 is refracted in the image mode switching unit 200 to separate the light path corresponding to the right eye image and the light path corresponding to the left eye image. Accordingly, the display device according to the embodiment can implement a 3D image.

The image mode switching unit 200 includes a liquid crystal layer 230, a first transparent electrode substrate 210, and a second transparent electrode substrate 220.

The liquid crystal layer 230 is disposed between the first transparent electrode substrate 210 and the second transparent electrode substrate 220. The liquid crystal layer 230 may be driven by the first transparent electrode substrate 210 and the second transparent electrode substrate 220. As described above, the liquid crystal layer 230 can transmit the transmitted light without changing or changing the path of the transmitted light.

The liquid crystal layer 230 includes a liquid crystal accommodating portion 231, a groove 232 for accommodating the liquid crystal, and a liquid crystal 233.

The grooves 232 are formed on one surface of the liquid crystal accommodating portion 231 to receive the liquid crystal 233.

The grooves 232 extend in one direction. The grooves 232 extend side by side. The grooves 232 may have a lenticular shape. Accordingly, the liquid crystal 233 may be included in the liquid crystal layer 230 as a lenticular lens.

The liquid crystal 233 may have different refractive indices depending on whether an electric field is applied. The refractive index of the liquid crystal 233 when the electric field is applied is the same as the refractive index of the liquid crystal containing portion 231 while the refractive index of the liquid crystal 233 when the electric field is non- May be different.

The first transparent electrode substrate 210 and the second transparent electrode substrate 220 sandwich the liquid crystal layer 230.

The first transparent electrode substrate 210 and the second transparent electrode substrate 220 drive the liquid crystal layer 230. More specifically, the liquid crystal layer 230 may be driven by an electric field formed between the first transparent electrode substrate 210 and the second transparent electrode substrate 220. More specifically, the liquid crystal 233 can be aligned in a predetermined direction by an electric field formed by the first transparent electrode substrate 210 and the second transparent electrode substrate 220.

As shown in FIG. 3, the transparent electrode substrate 210 includes a base film 100 and a transparent electrode 110 disposed on the base film 100. Specifically, the first transparent electrode substrate 210 includes a first base film and a first transparent electrode disposed on the first base film. Similarly, the second transparent electrode substrate 220 includes the liquid crystal layer 230 and a second transparent electrode interposed between the second base film.

The first transparent electrode and the second transparent electrode are transparent conductors. Examples of the material used as the first transparent electrode and the second transparent electrode include indium tin oxide and indium zinc oxide.

The same base film may be used for the first base film and the second base film. Specifically, substantially the same base film as the base film having the characteristics described below may be used. Alternatively, only one of the first base film and the second base film can use substantially the same film as the base film having the characteristics described below.

The base film (the first base film and / or the second base film) according to the embodiment has a high phase difference. More specifically, the in-plane retardation of the base film may be about 3,000 nm or more. More specifically, the in-plane retardation of the base film may be about 5,000 nm or more. More specifically, the in-plane retardation of the base film may be about 10,000 nm or more. More specifically, the in-plane retardation of the base 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 base film (the first base film and / or the second base film) may be a uniaxially stretched film. More specifically, the base film may be a uniaxially stretched polyester film. More specifically, the base film may be a uniaxially stretched polyethylene terephthalate film.

That is, the base film may be stretched in one direction, not elongated in the other direction, or slightly elongated. For example, the base 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 base 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 base 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 base film may be a film stretched to about 6 times or less in the first direction.

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

For example, the base film may be divided into a plurality of grid areas having a square planar shape with one side of 0.3 to 2 cm in length, and 90% or more of the grid areas are defined as ± Wherein an orientation direction of the grid region is defined as an average orientation direction of the polymer included in the grid region and an orientation direction of the base film is defined as an average orientation direction of the grid regions.

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

Referring to FIG. 4, the base film 100 may be divided into a plurality of grid areas G having a rectangular planar shape. More specifically, the base film 100 may be divided into a plurality of grid areas G having a square planar shape with one side of 0.3 to 2 cm in length.

5 and 6, the orientation direction of the grid region G may be determined by the following method.

First, the base 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 base film (100) and the polarizing plates are arranged in parallel with 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 grid area G (L1: incident light of the base film). Then, the light (L2: base 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 around a rotation axis substantially perpendicular to the polarizing plates and the base film 100.

In accordance with the rotation, the intensity of the light transmitted through the polarizing plate 105 is measured (L3: polarized plate transmitting light). At this time, when the intensity of light transmitted through the polarizing plate 105 is the smallest, one of the polarizing plates (transmission axis) may be the alignment direction of each of the grid areas 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 base film 100 may be defined as an average orientation direction of the grid areas G. [ That is, the orientation direction of the base 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 base film 100 may have uniformly optical characteristics as a whole.

Fig. 7 shows a diagram showing the orientation direction of the base film and the orientation direction of the grid area. Referring to FIG. 7, the orientation direction of each of the grid areas G may be within a range of ± theta, with reference to the orientation direction of the base film 100. Preferably, the orientation direction of the grid area G may range from 0 to 5 deg., Preferably from 0 to 2 deg., Based on the orientation direction of the base film 100. [

The base 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 base film 100, 90% or more of the grid areas G may be within ± 2 ° with respect to the orientation direction of the base film 100, more preferably 95% or more of the grid areas G may have an orientation of the base film 100 Direction, and more preferably, at least 97% of the grid areas G have an orientation direction that is within ± 2 ° with respect to the orientation direction of the base film 100 . More preferably, 99% or more of the grid areas G may have an alignment direction that is within ± 2 ° with respect to the alignment direction of the base film 100.

The display device includes a liquid crystal layer 230 and the liquid crystal layer 230 includes a groove 232 extending in one direction for receiving the liquid crystal 233, The orientation direction of the film 100 (the first base film and / or the second base film) may correspond to the direction in which the groove 232 extends. That is, the orientation direction of the base film 100 may be substantially the same as the direction in which the groove 232 extends. More specifically, the angle between the orientation direction of the base film 100 and the direction in which the groove 232 extends may be within about 3 degrees.

The orientation direction of the base film 100 may correspond to the polarization direction (polarization axis) of the upper polarizer, which is in contact with the image mode switching unit 200, among the polarizers included in the display panel 510. That is, the alignment direction of the base film 100 may be substantially the same as the polarization direction of the upper polarizer. More specifically, the angle between the alignment direction of the base film 100 and the polarization direction of the upper polarizer may be within about 3 degrees.

The base film 100 (the first base film and / or the second base film) includes a polymer, and examples of the polymer include polyester, polyvinyl chloride, and polyimide, 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 base 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 base film 100 may be substantially transparent. The haze of the base film 100 may be about 5% or less, preferably about 3% or less, and more preferably about 2% or less.

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

The base film 100 may include additional layers as required.

FIGS. 8 and 9 show processes for manufacturing a base film according to an embodiment of the present invention.

The base 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 base film (100).

Referring to Fig. 8, 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 set in the range of Tg-100 ° C to Tg + 20 ° C, preferably in the range of Tg-70 ° C to Tg-5 ° C, with respect to the glass transition temperature (Tg) .

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. Thus, the base 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.

On the other hand, as shown in Fig. 9, 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 . When the unstretched film 101 is stretched to 6 times or less, no breakage occurs. 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. When the stretching temperature of the base film (100) is less than Tg, stretching itself becomes difficult, which is not preferable. When the stretching temperature exceeds Tg + 40 deg. C, the stress required for stretching becomes extremely low, Is insufficient, so that the base film and / or the base film can not exhibit desired physical properties, which is not preferable.

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

If the elongation speed is 200% / min or more, it is preferable that the orientation direction in the base film 100 is uniformly formed as a whole, and if the elongation speed is 500% / min or less, Can be produced.

Next, the stretched substrate film 100 is heated to a temperature higher than the Tg and lower than or equal to Tm-15 ° C with respect to the glass transition temperature (Tg) and the melting point (Tm) of the polyester resin contained in the base 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 base film 100 is made of polyethylene terephthalate, the base film 100 may be heat-treated at a temperature of about 170 캜 to 190 캜. The heat treatment process may be conducted for about 30 seconds to about 5 minutes.

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

Thereafter, the heat-treated base 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 substrate film 100 thus formed may be 0.5 to 5 m, preferably 1 to 3 m.

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

The orientation direction of the base film (100) included in the base film may correspond to the width direction or the longitudinal direction of the base film (100).

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

Thereafter, the base film 100 is wound by a winding roll 40.

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

The substrate film 100 thus formed in the form of a roll can be appropriately cut and used.

The base film can be used as a base film for a transparent electrode of a three-dimensional image display device.

Specifically, the base film may be used as a base film of a transparent electrode substrate used in the image mode switching unit 200.

At this time, the orientation direction of the base film may be substantially the same as the extending direction of the grooves for receiving the liquid crystal contained in the image mode switching unit 200.

The base film includes a polyester and has an in-plane retardation of about 3,000 nm or more.

In particular, the base film comprises a uniformly oriented polymer as a whole.

The substrate film 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) Wherein an orientation direction of the grid region G is defined as an average orientation direction of the polymer contained in the grid region G and an orientation direction of the base film is defined as a direction of the grid region G G). ≪ / RTI >

Preferably, at least 90% of the grid areas may have an orientation direction that is within +/- 2 degrees with respect to the orientation direction of the film.

Accordingly, even when the base film forms the video mode switching unit 200 together with the liquid crystal, it does not show iridescence spots.

Therefore, the display device according to the present embodiment can prevent degradation of image quality such as rainbow color and realize an image of improved image quality.

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 held by the tenter clips were cut out to prepare a base film having a thickness of 80 탆 and a width of 1.5 m.

Example  2 to 5

A base 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 base 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.

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 base 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 base films were measured.

First, each base 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 alignment direction of the substrate area 100 was calculated by averaging the alignment directions of the grid areas G.

Test Example 2: Orientation uniformity

The ratio of the number of grid areas G having an orientation direction within ± 2 degrees with respect to the orientation direction of the base film 100 among the total number of grid areas G of each base material film 100 is calculated as a percentage And the orientation uniformity was measured.

Test Example 3: Rainbow Color

An ITO layer of about 5 탆 was deposited on each of the base films obtained in the above Examples and Comparative Examples to prepare a transparent electrode substrate. A liquid crystal layer was disposed between the two transparent electrode substrates thus manufactured to produce a video mode switching unit. The liquid crystal layer has a liquid crystal accommodating portion in which a liquid crystal and a semi-cylindrical (5 占 퐉 wide) groove for accommodating the liquid crystal are formed. At this time, the extending direction of the grooves was arranged to coincide with the alignment direction of the base films. The image mode switching unit is mounted on a liquid crystal display panel (LG Display product).

Then, the 2D image and the 3D image were implemented using the backlight, and it was observed whether or not the rainbow colors were visually observed.

○: 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 base 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 to calculate heat shrinkage ratios in the width direction according to the following formula:

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 indices (nx, ny) and the refractive index (nz) in the thickness direction perpendicular to the base films obtained in the above Examples and Comparative Examples were measured using Abbe's refractive index meter (NAR-4T manufactured by Atago KK, ), 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: base film
101: undrawn film 105: polarizer
106: lower polarizer plate 110: transparent electrode
200: image mode switching unit 210: first transparent electrode substrate
220: second transparent electrode substrate 230: liquid crystal layer
231: liquid crystal storage part 232: groove for housing liquid crystal
233: liquid crystal 510: liquid crystal panel
520: lower polarizer plate 530: upper polarizer plate
600: light source G: grid area
W: width L1: base film incident light
L2: base film transmitted light L3: polarizing plate transmitted light

Claims (11)

Display panel; And
And a video mode switching unit disposed on the display panel,
The video mode switching unit
A first transparent electrode substrate disposed on the display panel;
A liquid crystal layer disposed on the first transparent electrode substrate; And
And a second transparent electrode substrate disposed on the liquid crystal layer,
The first transparent electrode substrate
A first base film disposed on the display panel; And
And a first transparent electrode disposed on the first base film,
Wherein the first base film comprises a polyester and has an in-plane retardation of 3,000 nm or more.
The method according to claim 1,
Wherein the first base film is divided into a plurality of grid areas having a square planar shape with one side of 0.3 to 2 cm in length, and 90% or more of the grid areas are measured in the direction of the orientation of the first base film Lt; RTI ID = 0.0 > 5 < / RTI &
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 first base film is defined as the average orientation direction of the grid regions.
3. The method of claim 2,
Wherein the liquid crystal layer includes grooves extending in one direction for accommodating the liquid crystal,
And the orientation direction of the first base film corresponds to the direction in which the groove extends.
3. The method of claim 2,
The second transparent electrode substrate
A second base film disposed on the liquid crystal layer; And
And a second transparent electrode interposed between the liquid crystal layer and the second base film,
Wherein the second base film comprises a polyester and has an in-plane retardation of 3,000 nm or more.
3. The method of claim 2,
Plane retardation of the first base film is 5,000 nm or more.
6. The method of claim 5,
Plane retardation of the first base film is 10,000 nm or more.
The method according to claim 6,
Plane retardation of the first base 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 first base film is a monoaxially 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,
Here, 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.

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