KR101424587B1 - Polarizer and Display Device Comprising The Same - Google Patents

Abstract

The present invention provides a polarizing plate comprising optical films including a release film, a retardation film, a polarizing film, and at least one adhesive layer positioned between the optical films, wherein the adhesive layer has a peak wavelength of 570 to 610 nm Wherein the transmittance of light having a peak wavelength of 570 to 610 nm in the adhesive layer is 50 to 95% and the transmittance of light having a peak wavelength in a range of 570 to 610 nm in the adhesive layer is decreased, The sensitivity of the light spectrum of 610 nm is reduced, the color coordinates are closer to the National Television System Committee (NTSC) color coordinates, the color reproduction ratio is increased, and the polarizing plate having the highest color reproduction rate at the transmittance of 50% is provided.

Polarizer

Description

[0001] The present invention relates to a polarizing plate and a display device including the polarizing plate.

1 is a cross-sectional view of a display device according to an embodiment of the present invention;

2 is a cross-sectional view of a polarizer according to an embodiment of the present invention.

3 is a view showing R, G, B emission spectra of a display device according to an embodiment of the present invention.

4 is a view illustrating a color coordinate of a display device according to an embodiment of the present invention.

Description of the Related Art [0002]

200: polarizer 210: release film

220: adhesive layer 230: first substrate layer

240: polarizing film 250: second substrate layer

260: retardation film

The present invention relates to a polarizing plate and a display device including the same.

In recent years, the importance of display devices has been increasing with the development of multimedia. A plasma display panel (PDP), a field emission display (FED), an organic light emitting display (OLED) And the like are put into practical use.

Among them, the liquid crystal display device is superior in visibility to a cathode ray tube, has a small average power consumption and a small calorific value, and the organic light emitting display has a response speed of 1 ms or less and a high response speed, , There is no problem in the viewing angle since it is self-luminescence, and it is attracting attention as a next generation flat panel display device.

Generally, a display device is provided with a polarizing plate on the outer surface of a display device to improve the image quality of the display device. The role of such a polarizing plate is to absorb the horizontal component of the external light and to rotate the vertical component by the? / 4 retardation film, thereby preventing transmission of external light.

However, in a conventional display device having a polarizing plate, the polarizing plate merely serves to prevent transmission of external light only by a polarizing function, so that the characteristics such as the color reproduction rate of the display device can not be improved.

Accordingly, the present invention provides a polarizing plate capable of improving the color reproduction ratio of a display device and a display device including the same.

In order to achieve the above object, the present invention provides a polarizing plate comprising optical films including a release film, a retardation film, and a polarizing film, and at least one adhesive layer positioned between the optical films, And a dye having a peak wavelength of 570 to 610 nm, wherein a transmittance of light having a peak wavelength of 570 to 610 nm in the adhesive layer is 50 to 95%, and a peak wavelength of 570 to 610 nm in the adhesive layer As the transmittance decreases, the sensitivity of the spectrum of light having a peak wavelength of 570 to 610 nm decreases, the color reproduction rate becomes closer to the NTSC (National Television System Committee) color coordinate, and the polarizing plate having the highest color reproduction rate at the transmittance of 50% .

The present invention also provides a light emitting device comprising a first substrate, a light emitting diode disposed on the first substrate, the light emitting diode including a first electrode, a light emitting layer, and a second electrode, a second substrate opposing the first substrate and sealing the light emitting diode, And a polarizing plate positioned on an outer surface of the first substrate or the second substrate, wherein the polarizing plate includes optical films including a retardation film and a polarizing film, and the polarizing plate is disposed between the optical films or between the first substrate and the second substrate Wherein the adhesive layer comprises a dye absorbing light having a peak wavelength of 570 to 610 nm and a peak wavelength of 570 to 610 nm in the adhesive layer, The transmittance is 50 to 95%, and as the transmittance of light having a peak wavelength of 570 to 610 nm in the adhesive layer is decreased, the sensitivity of the spectrum of light having a peak wavelength of 570 to 610 nm is decreased A color reproduction ratio is increased, and a color reproduction ratio is highest at the transmittance of 50%, which is closer to the color coordinates of National Television System Committee (NTSC).

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view illustrating a display device according to an embodiment of the present invention.

A display device according to an embodiment of the present invention is shown. In this embodiment, an organic light emitting display device is described as an example of a display device.

Referring to FIG. 1, a semiconductor layer 110 is disposed on a substrate 100 comprising glass, plastic or metal. A first insulating layer 115 as a gate insulating layer is formed on a substrate 100 including a semiconductor layer 110 and a second insulating layer 115 is formed on the first insulating layer 115 at a position corresponding to a predetermined region of the semiconductor layer 110, (120).

A second insulating film 125, which is an interlayer insulating film, is disposed on the substrate 100 including the gate electrode 120. A source electrode 130a and a drain electrode 130b are electrically connected to a predetermined region of the semiconductor layer 110 on the second insulating layer 125 to form a thin film transistor.

A third insulating film 135, which may be a planarizing film or a passivation film, is disposed on the substrate 100 including the source electrode 130a and the drain electrode 130b. A first electrode 140 electrically connected to one of the source electrode 130a and the drain electrode 130b is positioned on the third insulating layer 135. [

A fourth insulating layer 145, which is a pixel defining layer, is formed to open a certain region of the first electrode 140. The light emitting layer 150 is positioned on the first electrode 140 exposed by the fourth insulating layer 145 and the second electrode 155 is located on the light emitting layer 150 to form the organic light emitting diode.

The second substrate 160 is positioned so as to face the first substrate 100 including the organic light emitting diode and the first substrate 100 and the second substrate 160 are bonded together by the sealing material 170, Thereby constituting a display device.

The polarizing plate 200 is positioned on the outer surface of the second substrate 160, which is the side toward which light is emitted in the organic light emitting display device. The polarizing plate 200 may be adhered to the second substrate 160 by the adhesive layer described below.

In an embodiment of the present invention, the polarizer 200 is positioned on the outer surface of the second substrate 160. Alternatively, in the case of the backlight emitting light toward the back surface, the outer surface of the first substrate 100 The polarizer 200 may be positioned on the outer surface of the first substrate 100 and the second substrate 160 in the case of both-side light emission.

Hereinafter, a polarizing plate according to an embodiment of the present invention will be described in detail with reference to the drawings.

2 is a cross-sectional view of a polarizer according to an embodiment of the present invention.

Referring to FIG. 2, the polarizer 200 according to an embodiment of the present invention is located on the outer surface of the substrate in the direction in which the light of the display device is directed. The polarizing plate 200 can transmit only light that oscillates from the inside of the display device to the outside in the same direction as the polarization axis, and absorbs or reflects light that vibrates in the other direction.

The polarizing plate 200 includes an adhesive layer 220 located on the release film 210, a first base layer 230 located on the adhesive layer 220, A polarizing film 240 positioned on the layer 230, a second base layer 250 positioned on the polarizing film 240, and a retardation film 260 located on the second base layer 250 Optical films. Although not shown, a protective film for protecting the polarizing plate 200 may be placed on the retardation film 260.

More specifically, the release film 210 may be a substrate for supporting the polarizing plate 200, and may be made of a polyacrylic resin or a polyester resin. The release film 210 can be removed when the polarizing plate is attached to the display device.

The adhesive layer 220 may adhere the optical films or adhere the polarizing plate and the display device. The adhesive layer 220 may include at least one selected from the group consisting of an acrylic polymer, a silicone polymer, an ester polymer, a urethane polymer, an amide polymer, an ether polymer, a fluorine polymer, and rubber.

In addition, the adhesive layer 220 may further include a dye that absorbs light having a peak wavelength of 570 to 610 nm.

The dye contained in the adhesive layer 220 may be any dye that absorbs light having a peak wavelength of 570 to 610 nm. Examples of the dye include anthraquinone dyes, methine dyes, azomethine dyes, oxadine dyes, Selected from the group consisting of azo dyes, styryl dyes, keratin dyes, porphyrin dyes, dibenzofuranone dyes, ticetopyrrolopyrrole dyes, rhodamine dyes, xyanthene dyes and phyllomethine dyes. Or more can be used.

The kind and concentration of the dye contained in the adhesive layer 220 are not particularly limited as they are determined by the thickness of the adhesive layer or the peak wavelength of the absorbed light.

The dye contained in the adhesive layer 220 absorbs light having a peak wavelength of 570 to 610 nm, wherein the absorption rate of light in the peak wavelength range of the adhesive layer 220 may be 50 to 95%. If the light absorption rate of the peak wavelength of 570 to 610 nm of the adhesive layer 220 is 50% or more, there is an advantage that the power consumption of the display device can be prevented from being lowered too much. When the light absorption rate at a peak wavelength of 610 nm is 95% or less, there is an advantage that the color reproduction rate of the display device can be improved.

The adhesive layer 220 according to an embodiment of the present invention includes a dye that absorbs light having a peak wavelength of 570 to 610 nm and has a peak absorption rate of 50 to 95% The intensity of the point at which the peak wavelengths of G and R intersect in the spectrum can be lowered. Therefore, there is an advantage that the color purity and color reproduction ratio of G and R of the display device can be improved.

In the embodiment of the present invention, only one adhesive layer is formed on the release film. Alternatively, a plurality of adhesive layers may be formed between each optical film.

Next, the first base layer 230 supports the polarizing film, protects the polarizing film from external impact, and reinforces the durability, moisture resistance, and mechanical strength of the polarizing film. As the first base layer 230, a material having a high light transmittance, a relatively low birefringence, and a good hydrophilicity due to surface modification can be used. For example, triacetyl cellulose (TAC ) Can be used. The thickness of the first base layer 230 may be 50 to 100 占 퐉 to obtain sufficient strength.

Next, the polarizing film 240 exhibits polarization characteristics. One component of the unpolarized white light is absorbed by the conjugated structure of the oriented dichroic substance or the oriented polymer chain itself, and the other component perpendicular to the polarized film absorbs . As the polarizing film 240, for example, an iodine polarizing film, a dye polarizing film and a polyene polarizing film can be used.

The iodine polarizing film exhibits polarization by being oriented by a polyvinyl alcohol (PVA) chain in which the iodine ion chain is oriented in a stretched state. The dye-based polarizing film is also oriented by the PVA chain in which the dichroic dye is oriented by stretching Thereby exhibiting a polarizing property. On the other hand, the polyene polarizing film exhibits a polarizing property by forming a polyene by a dehydration reaction of a PVA film or a dehydrochlorination reaction of a PVC film.

Although an iodine polarizing film is described as an example of a polarizing film in one embodiment of the present invention, it is not limited thereto, and the polarizing film may be a dye-based polarizing film.

The polarizing film 240 has an absorption axis and a polarization axis. The absorption axis is an axis in which the iodine ion chain is oriented in the stretched direction. One of the two vertical components of the light oscillating in an arbitrary direction interacts with electrons of the polarizing film It is the axis that destroys the light component in the process of changing the electrical energy of light into the energy of the electron. The polarization axis is an axis perpendicular to this absorption axis, and transmits light oscillating in the direction of the polarization axis. The thickness of the polarizing film 240 may be 15 to 30 占 퐉.

Examples of the method for forming the polarizing film 240 include a method of laminating iodine after stretching the PVA film, a method of stretching after iodine is adsorbed on the PVA film, and a method of simultaneous salt-baking and stretching.

Next, since the second base layer 250 uses the same material as the first base layer 230, its explanation is omitted.

Referring to the retardation film 260, the retardation film 260 may be a lambda / 4 retardation film. The? / 4 retardation film serves to change the linearly polarized light to circularly polarized light or to convert the circularly polarized light to linearly polarized light by giving a phase difference of? / 4 to two polarized components perpendicular to each other, parallel to the optical axis of the retardation film.

Hereinafter, embodiments according to the polarizing plate of the present invention will be described. However, the following examples are only a preferred embodiment of the present invention, and the present invention is not limited by the following examples.

Experiment 1: Measurement of R, G, B emission spectra according to the transmittance of adhesive layer

<Experimental Example 1>

An adhesive material containing an anthraquinone-based dye absorbing light having a peak wavelength of 590 nm was formed on the release film to a thickness of 10 μm to form a pressure-sensitive adhesive layer having a transmittance of 92% of light having a peak wavelength of 590 nm. Triacetyl-cellulose (TAC) was formed on the adhesive layer to a thickness of 50 탆 to form a first base layer. Polyvinyl alcohol (PVA) was formed on the first base layer to a thickness of 20 탆 to form a polarizing film. Triacetyl-cellulose (TAC) Mu m to form a second base layer. A? / 4 retardation film was formed on the second base layer to complete a polarizing plate.

<Experimental Example 2>

Except that an adhesive layer having a light transmittance of 90% at a peak wavelength of 590 nm was formed.

<Experimental Example 3>

Except that an adhesive layer having a light transmittance of 88% at a peak wavelength of 590 nm was formed.

&Lt; Comparative Example 1 &

Except that the dye absorbing light having a peak wavelength of 590 nm was removed to form an adhesive layer having a transmittance of light having a peak wavelength of 590 nm of 100%.

After the completed polarizing plate was attached to the organic electroluminescent display device according to each of the examples and comparative examples, the emission spectra of each of R, G and B were measured by driving the organic electroluminescent display device.

Referring to FIG. 3, emission spectra of R, G and B according to Experimental Examples 1 to 3 and Comparative Example 1 are shown. It can be seen that the emission spectra of R, G and B of the polarizing plate according to Experimental Examples 1 to 3 of the present invention are shifted to the right as compared with Comparative Example 1. That is, the sensitivity (vertical axis) of the point where the emission spectrum of G intersects with the emission spectrum of R is lowered.

In other words, the fact that the sensitivity of the point where the emission spectrum of G intersects with the emission spectrum of R is low means that the ratio of G to R is low. Therefore, the polarizing plate and the display device having the polarizing plate according to the embodiment of the present invention have an advantage that the ratio of color mixture of G and R is lowered, and the color purity and color reproduction ratio can be improved.

Experiment 2: Measurement of color coordinates of R, G, B according to the transmittance of the adhesive layer

<Experimental Example 4>

An adhesive material containing an anthraquinone-based dye absorbing light having a peak wavelength of 590 nm was formed on the release film to a thickness of 10 μm to form a pressure-sensitive adhesive layer having a transmittance of 92% of light having a peak wavelength of 590 nm. Triacetylcellulose (TAC) was formed on the adhesive layer to a thickness of 50 탆 to form a first base layer. Polyvinyl alcohol (PVA) was formed on the first base layer to a thickness of 20 탆 to form a polarizing film. Triacetyl-cellulose (TAC) Mu m to form a second base layer. A? / 4 retardation film was formed on the second base layer to complete a polarizing plate.

<Experimental Example 5>

Except that an adhesive layer having a light transmittance of 90% at a peak wavelength of 590 nm was formed.

<Experimental Example 6>

Except that an adhesive layer having a light transmittance of 88% at a peak wavelength of 590 nm was formed.

&Lt; Comparative Example 2 &

Except that the dye absorbing light having a peak wavelength of 590 nm was removed to form an adhesive layer having a light transmittance of 100% at a peak wavelength of 590 nm.

The polarizing plate completed according to each of Experimental Examples 4 to 6 and Comparative Example 2 was attached to an organic electroluminescent display device and then the color coordinates of R, G and B were measured by driving the organic electroluminescent display device, .

Referring to FIG. 4, the color coordinates of R, G, and B according to Experimental Examples 4 to 6 and Comparative Example 2 are shown. It can be seen that the color coordinates of R, G, and B of the organic light emitting display device having the polarizing plate according to Experimental Examples 4 to 6 of the present invention are closer to the NTSC (National Television System Committee) color coordinates as compared with Comparative Example 2. [

That is, the color coordinate system of the display device having the polarizing plate according to the embodiment of the present invention is superior to the conventional polarizing plate having no dye.

Experiment 3: Measurement of color reproducibility according to the transmittance of the adhesive layer

<Experimental Example 7>

An adhesive material containing an anthraquinone dye absorbing light having a peak wavelength of 590 nm was formed on the release film to a thickness of 10 탆 to form a pressure-sensitive adhesive layer having a light transmittance of 95% with a peak wavelength of 590 nm. Triacetyl-cellulose (TAC) was formed on the adhesive layer to a thickness of 50 탆 to form a first base layer. Polyvinyl alcohol (PVA) was formed on the first base layer to a thickness of 20 탆 to form a polarizing film. Triacetyl-cellulose (TAC) Mu m to form a second base layer. A? / 4 retardation film was formed on the second base layer to complete a polarizing plate.

<Experimental Example 8>

And a pressure-sensitive adhesive layer having a light transmittance of 92% at a peak wavelength of 590 nm was formed.

<Experimental Example 9>

Except that an adhesive layer having a light transmittance of 90% at a peak wavelength of 590 nm was formed.

<Experimental Example 10>

Except that an adhesive layer having a transmittance of 88% of light having a peak wavelength of 590 nm was formed.

&Lt; Experimental Example 11 &

And an adhesive layer having a light transmittance of 78% at a peak wavelength of 590 nm was formed.

<Experimental Example 12>

Except that an adhesive layer having a light transmittance of 67% at a peak wavelength of 590 nm was formed.

<Experimental Example 13>

The same procedure as in Experimental Example 7 was carried out except that the adhesive layer had a transmittance of 56%.

<Experimental Example 14>

Except that a pressure-sensitive adhesive layer having a light transmittance of 50% at a peak wavelength of 590 nm was formed.

&Lt; Comparative Example 3 &

Except that the dye absorbing light having a peak wavelength of 590 nm was removed to form a pressure-sensitive adhesive layer having a light transmittance of 100% at a peak wavelength of 590 nm.

After attaching the polarizing plate completed according to Experimental Examples 7 to 14 and Comparative Example 3 to the organic light emitting display device, the color reproduction ratio was measured by driving the organic light emitting display device.

Permeability (%) of the adhesive layer Color recall (%) Comparative Example 3 100 75.37 Experimental Example 7 95 76.87 Experimental Example 8 92 78.77 Experimental Example 9 90 79.56 Experimental Example 10 88 80.58 Experimental Example 11 78 85.01 Experimental Example 12 67 90.01 Experimental Example 13 56 94.58 Experimental Example 14 50 96.55

As shown in Table 1, it can be seen that the color reproduction ratio of the display device having polarized light according to Experimental Examples 7 to 14 of the present invention is higher than that of Comparative Example 3.

More specifically, by forming a pressure-sensitive adhesive layer containing a dye absorbing light having a peak wavelength of 570 to 610 nm and using a polarizer having a transmittance of light in the peak wavelength range of 50 to 95% in the pressure-sensitive adhesive layer, R and G It is possible to improve the color purity and color reproduction ratio of the display device.

As described above, in the polarizing plate and the display device including the polarizing plate according to the embodiment of the present invention, a dye that absorbs light having a peak wavelength of 570 to 610 nm is added to the adhesive layer of the polarizing plate to improve the color reproduction ratio of the display device .

Accordingly, there is an advantage that a polarizing plate capable of improving the display quality of an image and a display device including the same can be provided.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. In addition, the scope of the present invention is indicated by the following claims rather than the detailed description. Also, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

INDUSTRIAL APPLICABILITY As described above, the polarizing plate of the present invention and the display device including the same have the advantage of being able to provide a display device with improved color reproduction rate.

Claims (11)

1. A polarizing plate comprising optical films including a release film, a retardation film, and a polarizing film, and at least one adhesive layer positioned between the optical films, Wherein the adhesive layer comprises a dye absorbing light having a peak wavelength of 570 to 610 nm, The transmittance of light having a peak wavelength of 570 to 610 nm in the adhesive layer is 50 to 95%, and as the transmittance of light having a peak wavelength of 570 to 610 nm in the adhesive layer is decreased, the spectrum of light having a peak wavelength of 570 to 610 nm The sensitivity is reduced, the color coordinates are closer to the National Television System Committee (NTSC) color coordinates, the color reproduction rate is increased, the color reproduction ratio is highest at the transmittance of 50% The polarizing plate may include a polarizing plate disposed on the release film, a first base layer positioned on the adhesive layer, a polarizing film disposed on the first base layer, a second base layer disposed on the polarizing film, And optical films including the retardation film positioned on the second base layer, Wherein a transmittance of the adhesive layer is 50 to 56%, and a color reproduction rate of the adhesive layer is 96.55 to 94.58%. The method according to claim 1, The dyes may be selected from the group consisting of anthraquinone dyes, methine dyes, azomethine dyes, oxazine dyes, azo dyes, styryl dyes, keratin dyes, porphyrin dyes, dibenzofuranone dyes, A dyestuff, a rhodamine-based dye, a chitosan-based dye, and a filomethene-based dye. The method according to claim 1, Wherein the polarizing plate comprises base layers positioned between the retardation film and the polarizing film or between the polarizing film and the adhesive layer. delete The method according to claim 1, Wherein the adhesive layer is at least one selected from the group consisting of an acrylic polymer, a silicone polymer, an ester polymer, a urethane polymer, an amide polymer, an ether polymer, a fluorine polymer and rubber. A first substrate; A light emitting diode located on the first substrate, the light emitting diode including a first electrode, a light emitting layer, and a second electrode; A second substrate facing the first substrate and sealing the light emitting diode; And And a polarizer disposed on an outer surface of the first substrate or the second substrate, Wherein the polarizing plate comprises optical films including a retardation film and a polarizing film and at least one adhesive layer positioned between the optical films or at least one of the first and second substrates and the polarizing plate, Wherein the adhesive layer comprises a dye absorbing light having a peak wavelength of 570 to 610 nm, wherein a transmittance of light having a peak wavelength of 570 to 610 nm in the adhesive layer is 50 to 95%, a peak wavelength in the adhesive layer is 570 to 570 nm, As the transmittance of light at 610 nm decreases, the sensitivity of the spectrum of light with peak wavelengths of 570-610 nm decreases, closer to the NTSC (National Television System Committee) color coordinates, the color gamut increases, and the transmittance at 50% Color reproduction ratio, Wherein the polarizing plate comprises a pressure-sensitive adhesive layer disposed on the release film, a first base layer positioned on the pressure-sensitive adhesive layer, a polarizing film disposed on the first base layer, a second base layer positioned on the polarizing film, And optical films including the retardation film positioned on the second base layer, Wherein a transmittance of the adhesive layer is 50 to 56%, and a color reproduction rate of the adhesive layer is 96.55 to 94.58%. The method according to claim 6, The dyes may be selected from the group consisting of anthraquinone dyes, methine dyes, azomethine dyes, oxazine dyes, azo dyes, styryl dyes, keratin dyes, porphyrin dyes, dibenzofuranone dyes, A dye, a rhodamine-based dye, a chitosan-based dye, and a filomethene-based dye. The method according to claim 6, Wherein the polarizing plate includes base layers positioned between the retardation film and the polarizing film or between the polarizing film and the adhesive layer. delete The method according to claim 6, Wherein the adhesive layer is at least one selected from the group consisting of an acrylic polymer, a silicone polymer, an ester polymer, a urethane polymer, an amide polymer, an ether polymer, a fluorine polymer and rubber. Claim 11 has been abandoned due to the set registration fee. The method according to claim 6, And a thin film transistor including a semiconductor layer, a gate electrode, a source electrode, and a drain electrode on the substrate.

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