KR100615255B1 - Organic light emitting device - Google Patents

Abstract

The present invention discloses an organic light emitting display device in which a polarizing plate for blocking external light has a color coordinate suitable for B color having the lowest transmittance among R, G, and B colors.

The organic light emitting display device of the present invention comprises: a lower substrate on which a plurality of display elements displaying different colors are arranged; An upper substrate for encapsulating the lower substrate; And a polarizing member arranged on at least one of the upper and lower substrates, and the polarizing member has color coordinates suitable for a color having the lowest transmittance among a plurality of colors displayed by the display element.

The polarizing member has a color coordinate suitable for B color among R, G, and B colors, and the b * coordinate of the La * b * coordinate system is 2.5 or less.

Description

Organic light emitting device

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

1B is another cross-sectional view of an organic light emitting display device according to an embodiment of the present invention;

2A is a cross-sectional view of an organic light emitting display device according to another embodiment of the present invention;

2B is another cross-sectional view of an organic light emitting display device according to another embodiment of the present invention;

3A is a cross-sectional view of an organic light emitting display device according to another embodiment of the present invention;

3B is another cross-sectional view of an organic light emitting display device according to another embodiment of the present invention;

4A is a view showing color coordinates of white (W) in the organic light emitting display device of the present invention;

4B is a view showing color coordinates of blue (B) in the organic light emitting display device of the present invention;

4C is a view showing color coordinates of red (R) in the organic light emitting display device of the present invention;

Explanation of symbols on the main parts of the drawings

110, 210, 310: lower substrate 121, 221, 321: R EL element

123, 223, 323: G EL element 125, 225, 325: B EL element

130, 230, 330: upper substrate

140, 145, 200, 245, 341, 343, 347, 349: polarizer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display device, and more particularly, to an organic light emitting display device in which a polarizing plate for blocking external light has a color coordinate suitable for B color having the lowest transmittance among R, G, and B colors.

In general, an active matrix organic light emitting display (AMOLED) includes a plurality of pixels arranged on a substrate, and each pixel includes at least one switching thin film transistor, one driving thin film transistor, a capacitor, and an organic light emitting diode. Since the electrodes and the wiring of the thin film transistor and the capacitor are made of a metal material, light incident from the outside to the display element is reflected by the metal electrode and the wiring, and contrast is lowered, thereby degrading image quality.

In flat panel displays such as organic light emitting displays, contrast is greatly reduced according to the intensity of external light. In order to prevent the lowering of contrast due to external light, a black matrix for external light blocking was separately formed on the substrate or a polarizer was attached to the substrate.

Korean Laid-Open Patent Publication No. 2003-0037451 discloses a top-emitting organic light emitting display device having a black matrix by preventing reflection by external light. In the domestic patent, a light blocking film is formed on the entire surface of the lower part of the pixel electrode connected to the thin film transistor to block external light, thereby improving contrast. However, in the case of forming the light blocking film for blocking external light, a process for forming the light blocking film is required, which not only complicates the process but also in the case of partially forming the light blocking film without forming it entirely on the substrate, patterning the light blocking film. There was a problem in that a separate mask process for adding.

Meanwhile, US Pat. No. 5,596,246 discloses an organic light emitting display device that blocks external light using a circular polarizer. The organic light emitting display device disclosed in the above patent includes an organic EL element having a lower electrode and an upper electrode on an insulating substrate and an organic light emitting layer interposed between the two electrodes, and further comprising a reflective film arranged between the organic light emitting layer and the upper electrode. Equipped. The insulating substrate is encapsulated by an encapsulation substrate, and a circular polarizing plate is arranged on an outer surface of the insulating substrate. The U.S. patent can improve the contrast by blocking external light incident from the outside by attaching the circularly polarizing plate on the substrate, thereby improving the image quality.

In addition, in the case of a bottom emission type organic light emitting display device or a top emission type organic light emitting display device, a polarizing plate is arranged on an array substrate or an encapsulation substrate side to block external light. Japanese Patent Laid-Open No. 5-288209 discloses an organic light emitting display device with a polarizing plate for blocking external light. According to the Japanese patent, contrast can be improved by blocking external light by arranging a polarizing plate between an outer surface of the substrate from which light is emitted or between the substrate and the anode electrode.

However, in an organic light emitting display device having a polarizing plate for blocking external light, each pixel arranged on a substrate includes R, G, and B pixels, and one external polarizing plate for blocking external light includes all R, G, and B pixels. Commonly arranged with respect to the polarizing plate is typically colorless and has the same transmittance for all R, G, B colors.

Therefore, when the efficiency of a specific color among R, G, and B is inferior, there is a problem that it is difficult to match the white balance. In addition, when increasing the efficiency of a specific color whose efficiency is reduced in order to adjust the white balance, there is a problem that power consumption increases.

The present invention is to solve the problems of the prior art as described above, by providing a polarizing plate having a color coordinate suitable for the transmittance of B color having the lowest transmittance of R, G, B color to improve white balance and reduce power consumption An object of the present invention is to provide an organic light emitting display device.

In order to achieve the above object, the present invention provides a display device comprising: a lower substrate on which a plurality of display elements displaying different colors are arranged; An upper substrate for encapsulating the lower substrate; And a polarizing member arranged on at least one of the upper and lower substrates, wherein the polarizing member has a color coordinate suitable for a color having the lowest transmittance among a plurality of colors displayed by the display element. It features.

The lower substrate includes a plurality of display elements each displaying at least R, G, and B colors. The display device is an organic light emitting diode having a lower electrode, an upper electrode, and an organic layer interposed between upper and lower electrodes.

The polarizing member has a color coordinate suitable for B color among R, G, and B colors, and the b * coordinate of the La * b * coordinate system is 2.5 or less. The polarizing member includes a polarizing plate attached to the substrate or a polarizing material film coated on the substrate.

The polarizing member is arranged on the lower substrate of the upper substrate and the lower substrate, and arranged on one of the outer and inner surfaces of the lower substrate to block external light incident on the lower substrate.

The polarizing member is arranged on an upper substrate of the upper substrate and the lower substrate, and arranged on one of the inner and outer surfaces of the upper substrate to block external light incident on the upper substrate.

The polarizing plate member includes an upper polarizing member arranged on one of an inner side and an outer side of an upper substrate, and a lower polarizing member arranged on one of an inner side and an outer side of the lower substrate, thereby entering the lower substrate and the upper substrate. Block external light.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

1A illustrates a cross-sectional structure of a bottom emission type organic light emitting display device according to an embodiment of the present invention. In the bottom emission type organic light emitting display device of FIG. 1A, one pixel including R, G, and B pixels is illustrated.

Referring to FIG. 1A, a lower substrate 110 which is an array substrate in which a plurality of pixels are arranged in a matrix form and an upper substrate 130 which is an encapsulation substrate are provided. R, G, and B pixels constituting one pixel are arranged on the lower substrate 110, and each of the R, G, and B pixels is an R EL element 121, a G EL element 123, and a B EL element ( 125). The R EL element 121, the G EL element 123, and the B EL element 125 of each of the R, G, and B pixels are not shown in the drawing, but an anode electrode, an organic layer, and a cathode formed on the substrate 110 are shown. An electrode is provided.

The lower substrate 110 is bonded to the encapsulation substrate 130 using a sealant (not shown) to form the R, G, and B EL elements 121, 123, and 125 of the R, G, and B pixels. Protect. The bottom emission type organic light emitting display device 10 emits light from the organic layer of the R EL element 121, the G EL element 123, and the B EL element 125 constituting the R, G, and B pixels. It has a structure that is discharged toward the lower substrate (110).

The lower substrate 110 uses a transparent substrate, and the anode electrode uses a transmission electrode. The organic layer includes at least one organic layer of a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (Emitting layer), a hole suppression layer (HBL), an electron transport layer (ETL), an electron injection layer (EIL). .

The polarizing member 140 is arranged on the outer side of the inner side and the outer side of the lower substrate 110. Here, the inner surface of the lower substrate 110 refers to a surface in which the R, G, and B EL elements are arranged and encapsulated by the encapsulation substrate 130, and the outer surface refers to the opposing surface of the inner surface. do.

The polarizing member 140 is a polarizing plate attached to the outer surface of the lower substrate 110, is formed by attaching a polarizing film on the outer surface of the lower substrate 110. In addition, the polarizing member 140 is a polarizing material film coated on the outer surface of the lower substrate 110, and is formed by coating a coating polarizing liquid on the outer surface of the lower substrate 110.

Typically, the polarizing plate has no color and has the same transmittance for all colors. Therefore, when the transmittance of any one of the R, G, and B colors is relatively lower than the other colors, the efficiency of the color having the low transmittance is lowered. In order to achieve the white balance, the efficiency of the color having low transmittance should be increased to give uniform brightness, resulting in an increase in power consumption.

Accordingly, in the present invention, the polarizing member 140 is formed by attaching a polarizing plate having a color coordinate value suitable for a color having the lowest transmittance among R, G, and B colors, for example, B color, or by coating a polarizing material film. In the embodiment of the present invention, the polarizing member 140 uses a polarizing member having a color coordinate value suitable for B color having the lowest transmittance among the light emitted from the R, G, and B EL elements. * Use a polarizing member whose coordinates are 2.5 or less.

In general, in a color coordinate system for expressing color, a color image is represented in a color space including one axis representing brightness information and two coordinate axes representing color information. These color coordinate systems include RGB coordinate systems, Hue lightness saturation (HLS) coordinate systems, cyan magenta yellow kappa (CMYK) coordinate systems, luminance (Y) chrominance (U, V) coordinate systems, and luminance (Y) Information (I, Q) )) Coordinate system, La * b * coordinate system.

The La * b * coordinate system of the color coordinate system is a color coordinate system based on a C.I.E. (commission internaltion de L'Eclairage) chromaticity diagram, and is a coordinate system that displays colors based on a brightness factor and two color axes. In the La * b * coordinate system, the a * axis is two color axes, green and red, and the b * axis is two color axes, blue and yellow.

In an embodiment of the present invention, uniform luminance is obtained by using a polarizing member having a b * coordinate value of 2.5 * or less in a La * b * coordinate system suitable for B color having the lowest transmittance as a polarizing member for external light blocking. Therefore, by adjusting the color coordinates within a range of a specific color, for example, B color and not affecting the achromatic color, the white balance can be easily adjusted and power consumption can be reduced.

Figure 4a shows the color coordinates for white (W) in the C.I.E chromaticity diagram. Referring to FIG. 4A, it can be seen that the coordinate value for white when the b * coordinate values of La * b * coordinates of the polarizing member 140 have 3.5 and 2.5, respectively, is shifted.

Figure 4b shows the color coordinates for blue (B) in the C.I.E chromaticity diagram. Referring to FIG. 4B, it can be seen that the coordinate value for blue when the b * coordinate value of La * b * coordinates of the polarizing member 140 has 3.5 and 2.5, respectively, has changed by 0.005.

Figure 4c shows the color coordinates for the red (R) in the C.I.E chromaticity diagram. Referring to FIG. 4C, it can be seen that the coordinate values for red when the b * coordinate values of the La * b * coordinates of the polarizing member 140 have 3.5 and 2.5, respectively, are almost unchanged. Although not shown in the drawing, even in the case of green (G), even if the b coordinate value of La * b * coordinates of the polarizing member 140 has 3.5 and 2.5 respectively, the coordinate value for the green is almost unchanged.

Therefore, in the bottom emission type organic light emitting display device 10 as in the embodiment of the present invention, the polarizing member 140 of the La * b * coordinates of the polarizing member 140 on the lower substrate 110 is 2.5 or less. In the case of arranging the color coordinate values for red (R) and green (G), there is almost no change, but the color coordinate values for blue (B) change as shown in FIG. 4B and are shifted toward blue as shown in FIG. 4A. .

Therefore, when the efficiency of any one of the three colors of R, G, and B is low and it is difficult to adjust the white balance, as in the present invention, the b * of the La * b * coordinate system suitable for the color having the smallest efficiency among the R, G, and B colors is used. * By uniformly arranging the polarizing member having the coordinate value on the lower substrate, it is possible to obtain a uniform luminance, thereby reducing the power consumption.

1B illustrates another cross-sectional structure of a bottom emission organic light emitting display device according to an embodiment of the present invention.

The bottom emission type organic light emitting display device 15 illustrated in FIG. 1B has the same configuration as the bottom emission type organic light emitting display device 10 illustrated in FIG. 1A. However, only the polarizing member is arranged on the inner side of the inner side and the outer side of the lower substrate.

Referring to FIG. 1B, an organic light emitting display device 15 according to an exemplary embodiment of the present invention may include R, G, and B EL elements 121, 123, and 125 on an inner side surface of a lower substrate 110. Are arranged, and the lower substrate 110 is sealed by the upper substrate 130. The polarizing member 145 is arranged between the inner surface of the lower substrate 110 and the R, G, B EL elements 121, 123, and 125. The polarizing member 145 includes a polarizing material film coated on the inner surface of the lower substrate 110. The polarizing member 145 is formed by coating a coating polarizing solution on the inner surface of the lower substrate 110.

The polarizing member 145 uses a polarizing member having a color coordinate value suitable for B color having the lowest transmittance among the R, G, and B colors emitted from the R, G, and B EL elements, and b * of the La * b * coordinate system. A polarizing member having a coordinate value of 2.5 or less is used.

2A illustrates a cross-sectional structure of a top emission organic light emitting display device according to another embodiment of the present invention.

2A illustrates a cross-sectional structure of a top emission organic light emitting display device according to another embodiment of the present invention. In the top emission type organic light emitting display device of FIG. 2A, one pixel including R, G, and B pixels is illustrated.

Referring to FIG. 2A, a lower substrate 210 which is an array substrate in which a plurality of pixels are arranged in a matrix form and an upper substrate 230 which is an encapsulation substrate are provided. R, G, and B pixels constituting one pixel are arranged on the lower substrate 210, and each of the R, G, and B pixels includes an R EL element 221, a G EL element 223, and a B EL element ( 225). Although the R EL element 221, the G EL element 223, and the B EL element 225 of each of the R, G, and B pixels are not shown in the drawing, an anode electrode, an organic layer, and a cathode electrode are disposed on the substrate 210. It is provided.

The lower substrate 210 is bonded to the encapsulation substrate 230 by using a sealant (not shown in the drawing) to form the R, G, and B EL elements 221, 223, and 225 of the R, G, and B pixels. Protect. The front emission type organic light emitting display device 20 emits light from the organic layer of the R EL element 221, the G EL element 223, and the B EL element 225 constituting the R, G, and B pixels. It has a structure that is discharged toward the upper substrate 230.

The upper substrate 230 uses a transparent substrate, and the cathode electrode uses a transmission electrode. The organic layer includes at least one organic layer of a hole injection layer (HIL), a hole transport layer (HTL), an emission layer, an hole suppression layer (HBL), an electron transport layer (ETL), and an electron injection layer (EIL). do.

The polarizing member 340 is arranged on the outer side of the inner side and the outer side of the upper substrate 230. Here, the inner surface of the upper substrate 230 refers to a surface on which the R, G, and B EL elements of the lower substrate 210 are arranged, and the outer surface refers to an opposing surface of the inner surface.

The polarizing member 240 is a polarizing plate attached to the outer surface of the upper substrate 230, is formed by attaching a polarizing film on the outer surface of the upper substrate 230. In addition, the polarizing member 340 is a polarizing material film coated on the outer surface of the upper substrate 230, and is formed by coating a coating polarizing liquid on the outer surface of the upper substrate 230. The polarizing member 240 is formed by attaching a polarizing plate having a color coordinate value suitable for a color having the lowest transmittance among R, G, and B colors, for example, B color, or by coating a polarizing material film.

In the exemplary embodiment of the present invention, the polarizing member 240 is a polarizing member having a color coordinate value suitable for B color having the lowest transmittance among the light emitted from the R, G, and B EL elements, and the b * coordinate of the La * b * coordinate system. A polarizing member having a value of 2.5 or less is used.

2B illustrates another cross-sectional structure of a top-emitting organic light emitting display device according to another embodiment of the present invention.

The top emission type organic light emitting display device 25 illustrated in FIG. 2B has the same configuration as the top emission type organic light emitting display device 20 illustrated in FIG. 2A. The only difference is that the polarizing member is arranged on the inner side of the inner side and the outer side of the upper substrate.

Referring to FIG. 2B, the organic light emitting display device 25 according to another exemplary embodiment of the present invention may include R, G, and B EL elements 221, 223, and 225 on the inner surface of the lower substrate 210. Is arranged, and the lower substrate 210 is sealed by the upper substrate 230. The polarizing member 245 is arranged on the inner side surface of the upper substrate 230. The polarizing member 245 includes a polarizing material film coated on the inner surface of the upper substrate 230.

The polarizing member 245 uses a polarizing member having a color coordinate value suitable for B color having the lowest transmittance among the R, G, and B colors emitted from the R, G, and B EL elements, and b * of the La * b * coordinate system. A polarizing member having a coordinate value of 2.5 or less is used.

3A illustrates a cross-sectional structure of a double-sided organic light emitting display device according to another embodiment of the present invention. In the double-side organic light emitting display device of FIG. 3A, one pixel including R, G, and B pixels is illustrated.

Referring to FIG. 3A, a lower substrate 310 which is an array substrate in which a plurality of pixels are arranged in a matrix form and an upper substrate 330 which is an encapsulation substrate are provided. R, G, and B pixels constituting one pixel are arranged on the lower substrate 310, and each of the R, G, and B pixels includes an R EL element 321, a G EL element 323, and a B EL element ( 325). Although the R EL element 321, the G EL element 323, and the B EL element 325 of each of the R, G, and B pixels are not shown in the drawing, an anode electrode, an organic thin film layer, and a cathode electrode are disposed on the substrate 310. It is provided.

The lower substrate 310 is bonded to the encapsulation substrate 330 by using a sealant (not shown in the drawing), so that the R, G, and B EL elements 321, 323, and 325 of the R, G, and B pixels are attached. Protect. The double-sided organic light emitting display device 30 emits light from the organic layer of the R EL element 321, the G EL element 323, and the B EL element 325 constituting the R, G, and B pixels. The lower substrate 310 and the upper substrate 330 has a structure that is discharged respectively.

The upper substrate 230 and the lower substrate 310 use a transparent substrate, and the anode electrode and the cathode electrode use a transmissive electrode. The organic layer includes at least one organic layer of a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (Emitting layer), a hole suppression layer (HBL), an electron transport layer (ETL), an electron injection layer (EIL). .

The upper polarizing member 343 is arranged on the outer side of the inner side and the outer side of the upper substrate 330, and the lower polarizing member 341 is arranged on the outer side of the inner side and the outer side of the lower substrate 310. do. Here, the inner surface of the upper substrate 330 refers to a surface on which the R, G, and B EL elements are arranged in the lower substrate 310, and the outer surface refers to an opposing surface of the inner surface.

The upper polarizing member 343 and the lower polarizing member 341 are polarizing plates attached on the outer surfaces of the upper substrate 230 and the lower substrate 310, and the polarizing film is formed on the upper substrate 330 and the lower substrate 310. Are attached to the outer surface of each). In addition, the upper polarizing member 343 and the lower polarizing member 341 are polarizing material films coated on the outer surfaces of the upper substrate 330 and the lower substrate 310, respectively, and the coating polarizing liquid is coated on the upper substrate 330. And formed on the outer surface of the lower substrate 310, respectively.

The upper polarizing member 343 and the lower polarizing member 341 are formed by attaching a polarizing plate having a color coordinate value suitable for a color having the lowest transmittance among R, G, and B colors, for example, B color, or by coating a polarizing material film. do. In the embodiment of the present invention, as the upper polarizing member 343 and the lower polarizing member 341, a polarizing member having a color coordinate value suitable for B color having the lowest transmittance among the light emitted from the R, G, and B EL elements is used. , The polarizing member whose b * coordinate value of La * b * coordinate system has a value of 2.5 or less is used.

3B illustrates another cross-sectional structure of a double-sided organic light emitting display device according to another embodiment of the present invention.

The double-sided organic light emitting display device 35 shown in FIG. 3B has the same configuration as the double-sided organic light emitting display device 30 shown in FIG. 3A. However, only the polarizing member is arranged on the inner side of the inner side and the outer side of the upper substrate and the inner side of the inner side and the outer side of the lower substrate.

Referring to FIG. 3B, an organic light emitting display device 35 according to another exemplary embodiment of the present invention may include R, G, and B EL elements 321, 323, and 325 on an inner surface of a lower substrate 310. The lower substrate 310 is encapsulated by the upper substrate 330. The lower polarizing member 347 is arranged between the inner surface of the lower substrate 310 and the R, G, B EL elements 321, 323, and 325, and is disposed on the inner surface of the upper substrate 330. The upper polarizing member 349 is arranged. The lower polarizing member 347 and the upper polarizing member 349 include a polarizing material film coated on inner surfaces of the lower substrate 310 and the upper substrate 330.

The upper polarizing member 349 and the lower polarizing member 347 are formed by coating a polarizing polarizing material film having a color coordinate value suitable for a color having the lowest transmittance among R, G, and B colors, for example, B color. In the embodiment of the present invention, as the upper polarizing member 349 and the lower polarizing member 347, a polarizing member having a color coordinate value suitable for B color having the lowest transmittance among the light emitted from the R, G, and B EL elements is used. , The polarizing member whose b * coordinate value of La * b * coordinate system has a value of 2.5 or less is used.

In the double-sided organic light emitting display device according to another embodiment of the present invention, the polarizing plate or the polarizing material film is arranged on the outer side of the lower substrate or the polarizing material film is arranged on the inner side of the lower substrate. The polarizing member is arranged on the outer side of the upper substrate and the polarizing member is arranged on the inner side of the lower substrate, or the polarizing member is arranged on the inner side of the upper substrate and the polarizing member is arranged on the outer side of the lower substrate. It is also possible.

According to the embodiment of the present invention as described above, by blocking the external light blocking polarizing member having a La * b * coordinate value suitable for B color having the lowest transmittance of R, G, B color on the upper and lower substrates, Not only can the effect be obtained, but the luminance can be improved by improving the transmittance of B color without affecting achromatic color, thereby reducing the power consumption.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (9)

A lower substrate on which a plurality of display elements displaying different colors are arranged; An upper substrate for encapsulating the lower substrate; A polarizing member arranged on at least one of the upper and lower substrates, And the polarizing member has a color coordinate suitable for a color having the lowest transmittance among a plurality of colors displayed by the display element. The flat panel display of claim 1, wherein the lower substrate includes a plurality of display elements each displaying at least R, G, and B colors. The flat panel display of claim 2, wherein the polarizing member has a color coordinate suitable for B color among R, G, and B colors. The flat panel display of claim 3, wherein the polarizing member has a b * coordinate of a La * b * coordinate system of 2 or less. According to claim 1, wherein the polarizing member is arranged on the lower substrate of the upper substrate and the lower substrate, arranged on one of the outer surface and the inner surface of the lower substrate to block the external light incident on the lower substrate. Display. According to claim 1, wherein the polarizing member is arranged on the upper substrate of the upper substrate and the lower substrate, arranged on one of the inner surface and the outer surface of the upper substrate to block external light incident on the upper substrate. Display. The lower polarizing member of claim 1, wherein the polarizing member includes an upper polarizing member arranged on one of an inner side and an outer side of an upper substrate, and a lower polarizing member arranged on one of an inner side and an outer side of the lower substrate. A flat panel display comprising: blocking external light incident on a substrate and an upper substrate. The flat panel display of claim 1, wherein the display device is an organic light emitting device having a lower electrode, an upper electrode, and an organic layer interposed between upper and lower electrodes. The flat panel display of claim 1, wherein the polarizing member comprises one of a polarizing plate attached to a substrate and a polarizing material film coated on the substrate.

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