KR101950813B1 - Coatable phase retardation film and electroluminescence display device having thereof - Google Patents

Abstract

The present invention relates to a retardation film that can be simply manufactured by a simple process without a separate film, including a polarizer; A first support and a second support disposed on the lower surface and the upper surface of the polarizer, respectively; And a lambda / 4 liquid crystal phase layer which is applied to the lower surface of the first support and delays the phase of transmitted light.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a coating type retardation film and an organic electroluminescence display device having the same,

The present invention relates to a retardation film, and more particularly, to a coating type retardation film capable of reducing a manufacturing cost and greatly reducing a thickness by laminating a? / 4 liquid crystal phase layer directly on a film, and an organic electroluminescence display device will be.

2. Description of the Related Art Recently, various flat panel display devices capable of reducing weight and volume, which are disadvantages of cathode ray tubes (CRTs), have been developed. Such flat panel display devices include liquid crystal display devices, field emission display devices, plasma display panels and organic electroluminescent display devices.

Among these flat panel display devices, a plasma display has attracted attention as a display device that is most advantageous for a large-sized, small-sized and large-sized display because of its simple structure and manufacturing process. However, it has a disadvantage of low luminous efficiency, low luminance and high power consumption. On the other hand, the liquid crystal display device is disadvantageous in that it is difficult to form a large screen because of the semiconductor process, and the power consumption is large due to the backlight unit. In addition, the liquid crystal display element has a characteristic that light loss is large and a viewing angle is narrow due to optical elements such as a polarizing filter, a prism sheet, and a diffusion plate.

On the other hand, the organic electroluminescent display device is divided into an inorganic electroluminescent display device and an organic electroluminescent display device depending on the material of the light emitting layer and is self-luminous device which emits itself, has a high response speed, and has a large luminous efficiency, brightness and viewing angle . The inorganic electroluminescent display device consumes more power than the organic electroluminescent display device and can not obtain high brightness and can not emit various colors of R (Red), G (Green), and B (Blue). On the other hand, organic electroluminescence display devices are being actively studied because they can be driven at a low DC voltage of several tens volts, have a fast response speed, obtain high brightness, emit various colors of R, G, and B .

However, such an organic light emitting display device has the following problems. That is, the organic light emitting display device is mainly used as a display device of a portable device, and is used indoors, but is also used outside. In the case where the organic light emitting display device is used from outside, when light outside is input to the organic light emitting display device and reflected, the light emitted from the organic light emitting display device and the light reflected from the outside are mixed, The light emitted from the organic light emitting display device, that is, the image realized by the organic light emitting display device, can not be recognized.

In order to solve such a problem, a configuration in which a retardation film blocking light reflected from the organic light emitting display device is attached to the top surface of the organic light emitting display device has been recently introduced.

As shown in Fig. 1, the retardation film 40 comprises a? / 4 phase film 42 and a linear polarizer 46 disposed thereon. At this time, the optical axis direction of the linear polarizer 46 and the? / 4 phase film 42 is formed at an angle of 45 °.

In this structure, since the light emitted from the organic light emitting display device 42 is unpolarized light, the phase difference film 40 is circularly polarized while transmitting the light through the? / 4 phase film 42, The linearly polarized light is output as a linearly polarized light while the polarized state is changed, so that the user can recognize the image displayed on the organic light emitting display device 42.

The external light incident from outside is first transmitted through the linear polarizer 46, and the natural light is linearly polarized in the horizontal direction while passing through the linear polarizer 46. Then, when the linearly polarized light passes through the? / 4 phase film 42, the left-handed circularly polarized light is changed into a left-handed circularly polarized light, which is reflected by the organic light- The polarization state is changed. The right circularly polarized light is linearly polarized while passing through the? / 4 phase film 42. Since the direction of the linearly polarized light at this time is vertical, the linearly polarized light in this vertical direction is blocked by the linearly polarizing plate 46, So that the user can not recognize the reflected external light.

In general, the? / 4 phase film 42 is formed by stretching a film such as triacetyl cellulose (TAC) in one direction, and the linear polarizer 46 is also formed by stretching a film such as triacetyl cellulose (TAC) . At this time, in the optical axis direction of the? / 4 phase film 42 and the linear polarizer 46, the film is formed in the stretching direction.

The lambda / 4 phase film 42 and the linear polarizer 46 are laminated and attached to the organic electroluminescent display device. The lambda / 4 phase film 42 and the linear polarizer 46 may be joined together in various ways, Currently, 'roll to roll' is used.

In the 'roll to roll' method, after the λ / 4 phase film 42 and the linear polarizer 46 are wound on the two rolls, the λ / 4 phase film 42 and the linear polarizer 46, which are unwound from the respective rolls, . At this time, the optical axes of the? / 4 phase film 42 and the linear polarizer 46 are parallel to each other.

However, as described above, since the optical axis direction of the? / 4 phase film 42 and the linear polarizer 46 has an angle of 45 °, the 'roll to roll' Method. In the 'roll to sheet' method, one of the λ / 4 phase film 42 and the linear polarizer 46 is wound on a roll and the other is placed in a sheet form, and then the film released from the roll is attached to the sheet- 4 phase film 42 and the linear polarizing plate 46 in the direction of the optical axis.

However, even in the case of using the 'roll to sheet' method as described above, the consumption of the fabric increases when the λ / 4 phase film 42 is manufactured.

That is, as shown in FIG. 2, the film material 42a produced by the 'roll to sheet' method is stretched in the longitudinal direction of the raw material 42a so that the optical axis direction is formed in the longitudinal direction, Since the optical axis direction of the phase film 42 and the optical axis of the linear polarizer is at an angle of 45 degrees, in order to cut the film end 42a and form the? / 4 phase film 42, And should be formed in the diagonal direction of the four-phase film 42. Therefore, since the film material 42a is cut at an angle of 45 degrees instead of being cut in the longitudinal direction or the width direction, many regions of the film material 42a are discarded, which increases the manufacturing cost.

Further, since the thickness of the? / 4 phase film 42 is about several tens of micrometers, when the phase difference film 40 is made of the? / 4 phase film 42, the thickness becomes too large, There was a problem that the thickness was increased.

An object of the present invention is to provide a phase difference film capable of reducing manufacturing cost and reducing thickness by forming a phase layer by applying a liquid crystal material other than a separate phase film.

It is another object of the present invention to provide an organic light emitting display device having the above-described retardation film.

In order to achieve the above object, the retardation film of the present invention comprises a polarizer; A first support and a second support disposed on the lower surface and the upper surface of the polarizer, respectively; And a lambda / 4 liquid crystal phase layer which is applied to the lower surface of the first support and delays the phase of transmitted light.

The? / 4 liquid crystal phase layer is made of a reactive liquid crystal monomer, and an alignment layer for aligning the reactive liquid crystal monomer is further formed between the first support and the? / 4 liquid crystal phase layer.

The? / 4 liquid crystal phase layer is formed of a photoresist polymer comprising a main chain of a polymethacrylate system and a side chain made of the liquid crystalline material and a photoreactive material.

The organic electroluminescent display device according to the present invention includes an organic light emitting display panel having an organic light emitting layer to emit light to realize an image; A? / 4 liquid crystal phase layer which transmits light emitted from the organic light emitting layer formed on the light output side of the organic light emitting display panel and intercepts light reflected from the outside, delays the phase of the transmitted light, / 4 liquid crystal phase layer in accordance with the polarized state of the polarized light.

In the present invention, since a reactive liquid crystal monomer or a photoreactive polymer is applied to form a phase layer without using a separate phase film, it is possible to prevent an increase in manufacturing cost caused by a large amount of film fabricated when a conventional retardation film is used, The width of the retardation film can be greatly reduced, and a thin organic light emitting display device can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS Fig.
Fig. 2 shows processing of a phase film from an elongated fabric. Fig.
3 is a view showing a structure of a retardation film according to a first embodiment of the present invention.
4 is a view showing a structure of a retardation film according to a second embodiment of the present invention.
5 is a view showing a structure of a retardation film according to a third embodiment of the present invention.
6 is a view showing a structure of a retardation film according to a fourth embodiment of the present invention.
7 is a view showing a structure of a retardation film according to a fifth embodiment of the present invention.
8A to 8C are diagrams showing the structure of an organic light emitting display device having a retardation film.

Hereinafter, the present invention will be described in detail.

The present invention provides a phase difference film that can be applied. That is, in the present invention, the retardation film is formed in a separate film shape and is not attached to the organic electroluminescent display device, but can be simply applied to a polarizing plate to form a retardation film. Therefore, there is no need for a film laminating method such as 'roll to roll' or 'roll to sheet' to simplify the manufacturing process, and it is not necessary to consume the film material in order to laminate a retardation film having a polar axis different from that of the optical axis Therefore, the manufacturing cost can be reduced.

Various materials can be used for the retardation film of the present invention. That is, a reactive liquid crystal monomer containing a mseogen or a photo-orientable or photoreactive polymer may be used. The liquid crystal monomer or the photoreactive polymer is arranged in a specific direction so that the incident light is phase retarded so that the light emitted from the light emitting portion of the organic electroluminescence display element is transmitted, It is possible to prevent the deterioration of the image quality due to the use of the polarizing plate.

Of course, the present invention is not limited to the above-mentioned materials. The present invention can be applied to any material as long as it is made of a coatable material and can retard the incident light after being applied. Accordingly, the specific materials described below are merely illustrative of the present invention and are not intended to limit the invention.

Hereinafter, the present invention will be described more specifically with reference to the accompanying drawings.

3 is a view showing a retardation film according to a first embodiment of the present invention. 3, the retardation film 100 according to the present embodiment includes a polarizer 150, a first support 151 and a second support 152 disposed on the upper and lower surfaces of the polarizer 150, An alignment layer 120 formed on the first support 151 and a lambda / 4 liquid crystal phase layer 140 formed on the alignment layer 120.

The polarizer 150 is a film that can convert natural light into arbitrary polarized light. At this time, the polarizer 150 has a function of passing one polarized light component of two polarized light components and absorbing, reflecting, or scattering other polarized light components when the incident light is divided into two polarized light components orthogonal to each other Can be used. The optical film used for the polarizer 150 is not particularly limited. For example, a polymer film containing a polyvinyl alcohol (PVA) -based resin containing iodine or a dichroic dye as a main component, a dichromatic material An O-type polarizer in which a liquid crystal composition containing a liquid crystal compound is aligned in a certain direction, and an E-type polarizer in which a lyotropic liquid crystal is aligned in a certain direction.

The first support 151 and the second support 152 are for protecting the polarizer 150 and are generally made of a protection film having no retardation. Any of these protective films can be used, but mainly triacetylcellulose (TAC) is used. At this time, it is preferable that the second support 152 prevents the light incident from the outside using the surface-treated triacetylcellulose from being reflected by the second support 152.

The first and second supports 151 and 152 may be made of various materials such as soft materials such as glass and plastic, PET, cycloolefin polymer, and the like.

The alignment layer 120 is made of an alignment material such as polyimide or polyamide and is completed by applying polyimide or polyamide or the like, firing it, rubbing it with a rubbing roll or the like to form an alignment direction.

The? / 4 liquid crystal phase layer 140 uses a reactive liquid crystal monomer (reactive mesogens). The reactive liquid crystal monomer is a liquid crystal substance including a terminal group capable of polymerization, and is a monomer molecule having a liquid crystal phase including a terminal capable of polymerization with a mesogen that exhibits liquid crystallinity.

Generally, liquid crystals have the advantage of uniformly spreading on a large-area substrate and easily aligning molecules since they have crystal orientation and liquidity at the same time. When the reactive liquid crystal monomer aligned on the liquid crystal is polymerized, a crosslinked polymer network can be obtained while maintaining the aligned phase of the liquid crystal.

In the present invention, as the mesogen, a calamitic mesogen that expresses a nematic liquid crystal phase can be used. As the polymerizable terminal, an acrylic group or a methacrylic group capable of radical polymerization can be used. However, it can be used as any actionable terminal capable of polymerization.

As described above, when the reactive liquid crystal monomer is applied on the alignment layer 120, the reactive liquid crystal monomer is aligned along the alignment direction formed on the alignment layer 120, and the reactive liquid crystal monomer is aligned along a certain direction. Since the alignment direction of the alignment layer 120 is formed at an angle of 45 ° with the optical axis of the polarizer 150, the reactive liquid crystal monomers are also arranged at an angle of 45 ° with the optical axis of the polarizer 150 Polarizes the light.

In the phase difference film having such a structure, light incident from below the retardation film 100 is transmitted through the liquid crystal phase layer 140 and is retarded by a quarter phase, and then linearly polarized light is output through the polarizer 150, And is transmitted through the retardation film 100. On the other hand, after the light incident from the top of the retardation film 100 is polarized by the linearly polarized light while transmitting through the polarizer 150 (in this case, the polarized direction of the linearly polarized light is parallel to the polarizer 150) Polarized direction), the linearly polarized light state is transformed into the left-handed circularly polarized light state while being transmitted through the liquid crystal phase layer 140. Then, the left circularly polarized light is reflected from the organic light emitting display panel (not shown) on which the retardation film 100 is disposed and is deformed into right circularly polarized light, and the right circularly polarized light passes through the liquid crystal phase layer 140 And is again transformed into linearly polarized light. However, since the polarization direction is perpendicular to the polarization direction of the polarizer 150, the linearly polarized light is not completely transmitted through the polarizer 150, so that external light incident from the outside is incident on the retardation film 100 .

As described above, in the present invention, since the reactive liquid crystal monomer is applied to the support of the polarizer without attaching a separate? / 4 phase film to the polarizer, the production of the retardation film is simplified and the manufacturing cost can be reduced. Further, since the conventional liquid crystal phase film can be formed to a thickness of about 1 mu m, whereas the conventional? / 4 phase film has a thickness of several tens of mu m, the thickness of the retardation film can be greatly reduced, The thickness of the organic electroluminescent display device can be reduced.

4 is a view showing a structure of a retardation film according to a second embodiment of the present invention. At this time, the retardation film of this embodiment is different from the retardation film of the first embodiment only in the liquid crystal phase layer, and the other structures are the same. Therefore, the description of the same configuration will be simplified and only the other configurations will be described in detail.

4, the retardation film 200 according to the present embodiment includes a polarizer 250, a first support 251 and a second support 252 disposed on the upper and lower surfaces of the polarizer 250, And a λ / 4 self-aligned liquid crystal phase layer 240 formed on the first support body 251. At this time, the polarizer 250, the first support body 251 and the second support body 252 are the same as those of the first embodiment.

The λ / 4 self-aligned liquid crystal phase layer 240 uses a photo-orientable or photoreactive polymer. Specifically, the photoreactive polymer of this embodiment may be a liquid crystalline polymer having a mesogen-forming group exhibiting liquid crystallinity at a specific temperature range or a liquid crystalline low molecular weight or oligomer, which is optically anisotropic as the linearly polarized light is irradiated And mixtures thereof can also be used.

The photoreactive polymer is composed of a main chain of a polymethacrylate system and one or more side chains connected to the main chain, and each side chain is provided with one or two liquid crystal A photo-isomerization reaction or a photo-dimerization reaction occurs due to the provision of a photoreactive material as a terminal of the side chain. Also, a hydrogen bonding unit may be provided as a terminal.

Azobenzene group may be used as the liquid crystal material, and cinnamate group, coumarin group, benzylidenephthalimidine group and the like may be used as the photoreactive substance.

The following chemical formula 1 is a chemical structural formula of a photoreactive polymer containing an azobenzene group. At this time, the azobenzene group is bonded as a side chain to a main chain made of polymethacrylate as a liquid crystal group.

When the cinnamate group is included in the photoreactive material as the photoreactive group, a photoreactive group consisting of a homopolymer and a cinnamate having a liquid crystalline group in a main chain made of polymethacrylate may be combined as a side chain, A homomeric polymer having a liquid crystalline property may be bonded to a neighboring side chain through a hydrogen bond. In addition, a heteropolymer or a copolymer having an additional liquid crystalline group may be bonded while having a thinner and a liquid crystalline group in a main chain made of polymethacrylate.

The above-mentioned photoreactive polymer has a refractive index anisotropy (DELTA n) of about 0.08 to 0.20, and the retardation value can be controlled by controlling the applied thickness.

When such a photoreactive polymer is irradiated with linearly polarized light, a photo-isomerization reaction and a photo-doupling reaction occur in the photoreactive polymer, resulting in anisotropy in the photoreactive polymer, and the optical anisotropy So that the photoreactive polymer can be aligned in a predetermined direction.

When light is irradiated to the photoreactive polymer, the terminals attached to the side chain of the photoreactive polymer cause photo-isomerization and photo-tethering reactions. That is, when the linearly polarized light having the optical anisotropy is irradiated, the molecules of the side chain of the advertisement molecule in which the light is polarized parallel to the electric field direction absorb the energy of the irradiated light and the photo- It happens. As a result, the side chain in which the light is parallel to the polarization direction, that is, the direction of the electric field forms a Z-isomer and the side chain perpendicular to the direction of the electric field remains as an E-isomer, The direction of the side chain of the whole host material is determined to be perpendicular to the polarization direction of the light.

In this embodiment, the above-mentioned photoreactive polymer is applied to the first support 251, dried at a temperature of about 30-80 degrees, and then light such as linearly polarized ultraviolet light is applied to the applied photoreactive polymer, It is possible to form the lambda / 4 self-aligned liquid crystal phase layer 240 by firing at a temperature for about 10 minutes. At this time, ultraviolet rays irradiated to the photoreactive polymer have a wavelength of 250-400 nm and energy of about 10-500 mJ is irradiated. Since the optical axis direction of the λ / 4 self-aligned liquid crystal phase layer 240 is formed perpendicular to the polarization direction of the light (ie, ultraviolet ray), the direction of the optical axis of the liquid crystal phase layer 240 Can be adjusted.

Also in the phase difference film having such a structure, the light incident from below the retardation film 200 is transmitted through the self-aligned liquid crystal phase layer 240 and is retarded by? / 4 phase. Thereafter, light linearly polarized through the polarizer 250 is output And the light is transmitted through the retardation film 200. On the other hand, the light incident from the top of the retardation film 200 is transmitted through the polarizer 250, and after the polarized state is deformed by the linearly polarized light (the polarized direction of the linearly polarized light is parallel to the polarizer 250) Polarized direction), the linearly polarized light state is transformed into the left-handed circularly polarized light state while being transmitted through the self-aligned liquid crystal phase layer 240. Then, the left-handed circularly polarized light is reflected from the organic electroluminescence display device (not shown) on which the retardation film 200 is disposed to be deformed into right-handed circularly polarized light, and the right- And is again transformed into linearly polarized light. However, since the polarization direction is perpendicular to the polarization direction of the polarizer 250, the linearly polarized light is not completely transmitted through the polarizer 250, so that external light incident from the outside is incident on the retardation film 200 .

As described above, in the present invention, since the photoactive material of the liquid crystal phase layer 240 is self-aligned as the light is irradiated, the liquid crystal phase layer 240 can be formed without a separate alignment layer unlike the first embodiment, As a result, the manufacturing cost can be further reduced and the thickness of the retardation film can be further reduced.

5 is a view showing a structure of a retardation film according to a third embodiment of the present invention. The retardation film 300 according to this embodiment includes a polarizer 350, a first support 351 and a second support 352 disposed on the upper and lower surfaces of the polarizer 350, a second support 352 formed on the first support 351, / 2 self aligning liquid crystal phase layer 342 formed on the? / 2 self aligning liquid crystal phase layer 342 and a? / 4 self aligning liquid crystal phase layer 340 formed on the? / 2 self aligning liquid crystal phase layer 342. At this time, the polarizer 350, the first support body 351 and the second support body 352 are the same as those of the first embodiment.

At this time, the λ / 2 self-aligned liquid crystal phase layer 342 and the λ / 4 self-aligned liquid crystal phase layer 340 delay the phases of the input light by λ / 2 and λ / 4, respectively, . That is, the photoreactive polymer is applied in the desired direction by irradiating light such as linearly polarized ultraviolet rays after applying the photoreactive polymer as described in the fourth embodiment.

The difference between the second embodiment shown in FIG. 4 and the present embodiment is that a? / 2 self-aligned liquid crystal phase layer 342 is provided between the first support 351 and the? / 4 self-aligned liquid crystal phase layer 340 . Therefore, the input and output of the light of the present embodiment is the same as that of the second embodiment, so that light incident from the lower portion of the retardation film is transmitted, and light reflected from the upper portion is blocked. At this time, the? / 2 self-aligned liquid crystal phase layer 342 extends the bandwidth of transmitted light. Namely, when only the? / 4 self-aligned liquid crystal phase layer 340 is formed, only the light having a specific wavelength (for example, light having a wavelength of 550 nm) transmits the phase difference film while the? / 2 self- The light of a wide wavelength can be transmitted.

6 is a view showing a retardation film 400 according to a fourth embodiment of the present invention. The retardation film 400 of this embodiment includes a polarizer 450, a first support 451 and a second support 452 disposed on the upper and lower surfaces of the polarizer 450 and a second support 452 formed on the lower surface of the first support 451 / 2 liquid crystal phase layer 442 formed on the lower surface of the? / 2 liquid crystal phase layer 442 and a? / 2 liquid crystal phase layer 442 formed to be in contact with the lower surface of the alignment layer 420, And a self-aligned liquid crystal phase layer 440. At this time, the polarizer 450, the first supporting member 451 and the second supporting member 452 are the same as those of the first embodiment.

The λ / 2 liquid crystal phase layer 442 is made of a reactive liquid crystal monomer, and the reactive liquid crystal monomer is arranged along the alignment direction of the orientation layer 420. The λ / 4 self-aligned liquid crystal phase layer 440 is made of a photoreactive polymer, And is self-aligned as the polarized ultraviolet ray is irradiated.

7 is a view showing a retardation film 500 according to a fifth embodiment of the present invention. The retardation film 500 of this embodiment includes a polarizer 550, a first support 551 and a second support 552 disposed on the upper and lower surfaces of the polarizer 550 and a retardation film 552 formed on the first support 551 / 2 self alignment liquid crystal phase layer 542 and an alignment layer 520 formed on the lower surface of the? / 2 self aligning liquid crystal phase layer 542 and having an alignment direction determined; And a liquid crystal phase layer 540. At this time, the polarizer 550, the first supporting member 551 and the second supporting member 552 are the same as those of the first embodiment.

The λ / 4 liquid crystal phase layer 540 is composed of a reactive liquid crystal monomer, and the reactive liquid crystal monomers are arranged along the alignment direction of the orientation layer 520. The λ / 2 self-aligned liquid crystal phase layer 542 is formed of a photoreactive polymer, And is self-aligned as the polarized ultraviolet ray is irradiated.

As described above, in the present invention, instead of attaching a separate? / 4 phase film to a support of a polarizer, a coating material such as a reactive liquid crystal monomer or a photoreactive polymer is directly applied to a support to produce a retardation film , The manufacturing cost can be reduced, and the thickness of the retardation film can be greatly reduced. Further, in the case of forming a retardation film by a coating material like the present invention, since it has almost the same optical characteristics as in the case of attaching a separate? / 4 phase film, the present invention can take only a desired advantage .

Table 1 shows optical characteristics in a conventional retardation film having a? / 4 phase film and a retardation film coated with a? / 4 liquid crystal phase layer according to the first embodiment of the present invention.

Sample retardation film with a? / 4 phase film The retardation film coated with the? / 4 liquid crystal phase layer Luminance
(Lx) Luim (cd / m2) Luim (cd / m2) W B External light CR W B External light CR 0 274.4 0.013 21636 257.9 0.013 20482 200 283.5 8.867 32.0 284.6 8.863 32.8 1000 319.4 44.77 7.13 320.0 44.02 7.27 2000 365.1 89.53 4.08 361.6 87.27 4.14 10000 733.9 459.4 1.60 724.7 449.7 1.61 20000 1221 946.6 1.29 1201 926.3 1.30 30000 1668 1399 1.19 1641 1359 1.21

As shown in Table 1, when external light having a luminance of 0-3000Lu is incident, when a retardation film having a? / 4 phase film is applied, white (W) (i.e., the organic light emitting display device is full ) Is 274.4-1668 Lx, and the luminance of black (B) (i.e., when the organic light emitting display element is off) is 0.013 to 1399. [ Also, the contrast ratio CR for external light is 21638-1.19.

On the other hand, when external light having a luminance of 0-3000 Lu is incident, when a retardation film coated with a? / 4 liquid crystal phase layer is applied, the luminance of white W is 257.9-1641 Lx and the luminance of black B is 0.013- 1359. Also, the contrast ratio CR with respect to the external light is 20482-1.21.

Thus, when a retardation film with a? / 4 phase film is applied or when a retardation film coated with a? / 4 liquid crystal phase layer is applied, the luminance of white (W) and the luminance of black (B) , And the contrast ratio (CR) with respect to the external light is almost the same. This shows that almost the same effect can be obtained when using a phase difference film having a? / 4 phase film and a phase difference film having a? / 4 liquid crystal phase layer, respectively.

In addition, when the retardation film having the? / 4 liquid crystal phase layer of the present invention applied is applied while the reflectance of the organic light emitting display device is 6.2% when the retardation film having the? / 4 phase film of the present invention is applied The reflectance decreased to 5.7%.

As described above, in the present invention, it is possible to reduce the manufacturing cost and the thickness while exhibiting the same effect as the conventional retardation film having the? / 4 phase film attached thereto.

Hereinafter, a structure in which the above-described retardation film is applied to an organic light emitting display device will be described.

8A to 8C are diagrams showing the structure of an organic EL device to which a retardation film according to the present invention is attached, respectively. 8A and 8B are top emission organic electroluminescent display devices, and FIG. 8C is a bottom emission organic electroluminescent display device.

8A, an anode electrode 612 made of a metal is formed on the thin film transistor substrate 610, and an R-organic emission layer 614R for emitting red light, green light, and blue light, (614G), and a B-organic luminescent layer (614B) are formed.

Though not shown in the figure, a plurality of gate lines and data lines are disposed on the thin film transistor substrate 610 to form a plurality of pixels, and thin-film transistors (TFTs) including a gate electrode, a semiconductor layer, a source electrode, And a signal is applied to the anode electrode 612.

A cathode 616 made of a transparent conductive material is formed on the R-organic emitting layer 614R, the G-organic emitting layer 614G and the B-organic emitting layer 614B. A protective layer 618 is formed thereon.

On the other hand, a λ / 4 liquid crystal phase layer 640 is formed on the front surface of the upper substrate 622 made of a transparent material such as glass, and a polarizer 650 is attached to the rear surface. At this time, the? / 4 liquid crystal phase layer 640 may be formed of a reactive liquid crystal monomer or a photoreactive polymer. If the? / 4 liquid crystal phase layer 640 is formed of a reactive liquid crystal monomer, an orientation film is formed on the entire surface of the upper substrate 622, a? / 4 liquid crystal phase layer 640 is formed thereon, 640 is formed of a photoreactive polymer, the? / 4 liquid crystal phase layer 640 is directly applied to the upper substrate 622 and formed. The polarizing plate 650 includes the first and second supports and the polarizer shown in FIG.

Although not shown in the drawing, a? / 2 liquid crystal phase layer may be formed between the upper substrate 622 and the? / 4 liquid crystal phase layer 640. At this time, the? / 2 liquid crystal phase layer may also be formed of a reactive liquid crystal monomer or a photoreactive polymer.

As described above, in the present invention, the retardation film made of the support and the liquid crystal phase layer may be formed on the upper and lower surfaces of the transparent substrate of the organic electroluminescence display device without being attached to each other. In this case, since the polarization characteristics of the light transmitted through the transparent substrate of the organic electroluminescent display device are not changed at all, desired characteristics can be obtained by the retardation film.

The upper substrate 622 on which the polarizing plate 650 and the quarter phase liquid crystal layer 640 are formed on the upper and lower surfaces is attached to the protective layer 618 of the thin film transistor substrate 610 with the adhesive 620, Thereby completing the electroluminescent display device.

The monochromatic light emitted from the R-organic emitting layer 614R, the G-organic emitting layer 614G and the B-organic emitting layer 614B in the organic electroluminescence display device having such a structure is transmitted through the? / 4 liquid crystal phase layer 640 and the polarizing plate 650 ) And outputs the image to the upper part to implement an image.

The external light incident from the outside is first linearly polarized with a component parallel to the optical axis direction of the polarizing plate 650 and then the polarized state is changed to the left circularly polarized light (or right circularly polarized light) by the? / 4 liquid crystal phase layer 640 . The left-handed circularly polarized light (or right-handed circularly polarized light) is reflected by the anode 612 made of a metal to change its polarization state by right-handed circularly polarized light (or left-handed circularly polarized light) And becomes linearly polarized light. At this time, since the polarization direction of the light transmitted through the? / 4 liquid crystal phase layer 640 has a direction perpendicular to the optical axis direction of the polarizing plate 650, the light can not pass through the polarizing plate 650, Is reflected to the outside of the organic electroluminescence display device and is not output.

8B is the same as the structure shown in FIG. 8A and only the position of the? / 4 liquid crystal phase layer 640 is different. That is, in Fig. 8A, the polarizer and the [lambda] / 4 liquid crystal phase layer are formed on the upper and lower surfaces of the upper substrate, respectively. In this structure, the [lambda] / 4 liquid crystal phase layer 640 are formed on the polarizing plate 650 and a polarizing plate 650 is attached thereon. In this structure, the? / 4 liquid crystal phase layer 640 may be formed of a reactive liquid crystal monomer or a photoreactive polymer.

Further, a? / 2 liquid crystal phase layer made of a reactive liquid crystal monomer or a photoreactive polymer may be formed between the? / 4 liquid crystal phase layer 640 and the upper substrate 622.

In the organic EL display device having the structure shown in FIG. 8C, the? / 4 liquid crystal phase layer 640 and the polarizing plate 652 are formed on the lower surface of the thin film transistor substrate 610, i.e., outside the organic light emitting display device. The liquid crystal phase layer 640 may be formed of a reactive liquid crystal monomer or a photoreactive polymer and may be formed between the thin film transistor substrate 610 and the? / 4 liquid crystal phase layer 640 by a reactive liquid crystal monomer or a photoreactive polymer / 2 liquid crystal phase layer composed of a?

R, G, and B color filter layers 615R, 615B, and 615C are formed on the upper surface of the thin film transistor substrate 610, respectively. Although not shown in the drawing, a W color filter layer may be formed.

An inorganic insulating material such as SiO ₂ or SiN x is overlaid on the R, G and B color filter layers 615R, 615B and 615C to form an overcoat layer 617. ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) An anode 612 made of a transparent conductive material is formed.

A light emitting layer 614 is formed on the anode 612. The light emitting layer 614 is a white organic light emitting layer that emits white light. The light emitting layer 614 is formed by mixing a plurality of organic materials that emit red, green, and blue monochromatic light, or a plurality of light emitting layers that emit red, May be stacked. Although not shown in the drawing, the light emitting layer 614 is provided with an electron injection layer for injecting electrons and holes into the organic light emitting layer 614, an electron injection layer for injecting electrons and holes into the organic light emitting layer 614, May be formed.

On the light emitting layer 614, a cathode 614 is formed over the entire thin film transistor substrate 610, and a protective layer 616 is formed thereon. The cathode 614 is made of a metal such as Ca, Ba, Mg, Al, or Ag. The upper substrate 622 is attached to the structure by the adhesive 620 to complete the organic light emitting display device.

 In the organic EL display device of this structure, light is output through the thin film transistor substrate 610, and the external light input through the thin film transistor substrate 610 passes through the? / 4 liquid crystal phase layer 640 and the polarizer 652, .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Anyone who is engaged in the field of technology to which the present invention belongs will be able to easily create it.

100: retardation film 120: alignment film
140: liquid crystal phase layer 150: polarizer
151, 152:

Claims (20)

A thin film transistor substrate on which a thin film transistor is formed;
An anode formed on the thin film transistor substrate;
An organic light emitting layer formed on the anode substrate;
A cathode formed on the organic light emitting layer;
A protective layer formed on the cathode;
An adhesive formed on the protective layer;
A? / 4 self-aligned liquid crystal phase layer formed on the adhesive and made of a photoreactive polymer;
A? / 2 self-aligned liquid crystal phase layer formed on the? / 4 self-aligned liquid crystal phase layer and made of the photoreactive polymer;
An upper substrate formed on the? / 2 self-aligned liquid crystal phase layer;
A first support formed on the upper substrate;
A polarizer formed on the first support; And
And a second support formed on the polarizer,
The λ / 2 self-aligned liquid crystal phase layer is directly applied to the upper substrate and the λ / 4 self-aligned liquid crystal phase layer is directly applied to the λ / 2 self-aligned liquid crystal phase layer,
The? / 4 self-aligned liquid crystal phase layer and the protective layer are bonded together by the adhesive,
Wherein the photo-reactive polymer is photo-isomerized or photo-coupled and is self-aligned.
delete delete delete The photoreactive polymer according to claim 1,
A main chain of a polymethacrylate system; And
And a side chain made of a liquid crystal material and a photoreactive material.
delete delete delete delete delete A thin film transistor substrate on which a thin film transistor is formed;
An anode formed on the thin film transistor substrate;
An organic light emitting layer formed on the anode substrate;
A cathode formed on the organic light emitting layer;
A protective layer formed on the cathode;
An adhesive formed on the protective layer;
A λ / 4 self-aligned liquid crystal phase layer made of a photoreactive polymer formed on the adhesive and self-aligning due to a photo-isomerization reaction or a photo-coupling reaction;
An upper substrate formed on the? / 4 self-aligned liquid crystal phase layer;
A first support formed on the upper substrate;
A polarizer formed on the first support; And
And a second support formed on the polarizer,
Wherein the? / 4 self-aligned liquid crystal phase layer is directly applied to the upper substrate,
The? / 4 self-aligned liquid crystal phase layer and the protective layer are bonded together by the adhesive,
And the monochromatic light emitted from the organic light emitting layer is output to the upper part through the? / 4 self-aligned liquid crystal phase layer and the polarizer, thereby realizing an image. delete delete delete delete delete delete delete delete delete

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