KR20060060170A - Organic electroluminescent device having a polarizer - Google Patents

Abstract

The present invention relates to an organic electroluminescent device having a circular polarizing plate made of a mixed material in which a dye-based material and an iodine-based material are mixed. An organic EL device in which an indium tin oxide layer, an organic material layer, and a metal electrode layer are sequentially formed on an upper surface of a substrate includes an insulating film and a circular polarizer. The insulating layer is formed on the indium tin oxide layer and includes a black material. The circular polarizer is attached to the surface of the substrate opposite to the upper surface on which the indium tin oxide layer is formed to polarize light incident from the outside, and is made of a mixed material in which a dye-based material and an iodine-based material are mixed. Since the organic electroluminescent element uses a circular polarizer made of the mixed material, power consumption is reduced.

Organic electroluminescent element, polarization, transmittance

Description

Organic electroluminescent element which has polarizing plate {ORGANIC ELECTROLUMINESCENT DEVICE HAVING A POLARIZER}

1 is a cross-sectional view showing a conventional organic electroluminescent device.

2A is a cross-sectional view illustrating an organic EL device according to an exemplary embodiment of the present invention.

FIG. 2B is a diagram illustrating the transmittance of the organic EL device of FIG. 2A.

3A and 3B illustrate a process of blocking reflected light by using a circular polarizer according to an exemplary embodiment of the present invention.

The present invention relates to an organic electroluminescent device, and more particularly, to an organic electroluminescent device having a circular polarizing plate made of a mixed material corresponding to a mixture of a dye-based material and an iodine-based material.

The organic EL device generates light having a predetermined wavelength when a predetermined voltage is applied.

1 is a cross-sectional view showing a conventional organic electroluminescent device.

Referring to FIG. 1, a conventional organic electroluminescent device includes a substrate 10, an indium tin oxide layer 40, an insulating film 60, a partition 80, an organic material layer 100, a metal electrode layer 120, and a cell cap 140. ) And circular polarizer 160.

When a predetermined positive voltage is applied to the indium tin oxide layer 40 and a predetermined negative voltage is applied to the metal electrode layer 120, the organic material layer 100 generates light having a predetermined wavelength.

Light generated from the organic layer 100 passes through the circular polarizer 160 and is emitted to the outside.

In this case, since the circular polarizing plate 160 is made of an iodine-based material, the transmittance of the circular polarizing plate 108 with respect to the light generated from the organic layer 104, that is, the transmittance of the organic EL device is maintained at about 45%. It has a constant transmittance for all regions of the red, green, and blue wavelengths. However, in this case, the power applied to the red and blue wavelengths is higher than the power applied to the green wavelengths. That is, in order to maintain the same brightness for each pixel, the power consumption of the pixels emitting red and blue light had to be higher than that of the pixels emitting green light.

Therefore, there is a need for an organic EL device capable of reducing power consumption.

It is an object of the present invention to provide an organic electroluminescent device which improves contrast and reduces power consumption.

In order to achieve the above object, the organic electroluminescent device in which the indium tin oxide layer, the organic material layer and the metal electrode layer are sequentially formed on the upper surface of the substrate according to an embodiment of the present invention includes an insulating film and a circular polarizer. The insulating layer is formed on the indium tin oxide layer and includes a black material. The circular polarizer is attached to the surface of the substrate opposite to the upper surface on which the indium tin oxide layer is formed to polarize light incident from the outside, and is made of a mixed material in which a dye-based material and an iodine-based material are mixed.

The organic electroluminescent device according to the present invention uses a circular polarizing plate made of the mixed material, so that power consumption is reduced.

In addition, since the organic electroluminescent device according to the present invention uses an insulating film containing a black material, the contrast of the organic electroluminescent device is improved.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the organic electroluminescent device having a polarizing plate according to the present invention.

FIG. 2A is a cross-sectional view illustrating an organic EL device according to an exemplary embodiment of the present invention, and FIG. 2B is a diagram illustrating the transmittance of the organic EL device of FIG. 2A.

Referring to FIG. 2A, the organic electroluminescent device of the present invention includes a substrate 10, an indium tin oxide layer 40 (ITO layer), an insulating film 60, a partition wall 80, an organic material layer 100, The metal electrode layer 120, the cell cap 140, and the circular polarizer 200 are included.

ITO layer 40 corresponds to an anode and is deposited over substrate 10.

The organic material layer 100 is deposited on the ITO layer 40 and sequentially formed a hole injection layer (HIL), a hole transporting layer (HTL), an emitting layer (ETL), and an electron transport layer (Electron). Transporting Layer (ETL) and Electron Injection Layer (EIL).

The metal electrode layer 120 is made of metal, for example, aluminum (Aluminum, Al), corresponds to a cathode, and is deposited on the organic material layer 100.

Hereinafter, the light emission operation of the organic EL device will be described in detail.

When a predetermined positive voltage is applied to the ITO layer 40 and a predetermined negative voltage is applied to the metal electrode layer 120, the ITO layer 40 provides holes to the hole injection layer and the metal electrode layer 120. Provides electrons to the electron injection layer.

Subsequently, the hole injection layer smoothly injects the provided holes into the hole transport layer, and the electron injection layer smoothly injects the provided electrons into the electron transport layer.

Subsequently, the hole transport layer transports the injected holes to the light emitting layer, and the electron transport layer transports the injected electrons to the light emitting layer.

Subsequently, holes and electrons transported to the emission layer recombine to generate light having a specific wavelength.

Subsequently, the light generated from the light emitting layer passes through the substrate 10 and the circular polarizer 200 and is emitted to the outside.

The circular polarizer 200 is attached to the surface of the substrate 10, that is, the bottom surface of the substrate 10 opposite to the top surface on which the ITO layer 40 is formed, and passes the light generated from the light emitting layer with a predetermined transmittance. In addition, the circular polarizer 200 blocks external light to improve contrast of the organic light emitting diode. Detailed description thereof will be described below with reference to the accompanying drawings.

In addition, the circular polarizer 200 is made of a mixed material in which a dye-based material and an iodine-based material are mixed, unlike a conventional polarizing plate made of an iodine-based material. Dye-based materials generally do not absorb blue and red light better than iodine-based materials. Therefore, the circular polarizing plate 200 made of the mixed material passes the blue light and the red light better than the conventional flat plate made of the iodine-based material.

Therefore, even when less power is applied to pixels emitting blue light and red light, the organic electroluminescent device of the present invention can emit blue, green and red light with the same brightness. . That is, the power consumption of pixels emitting blue light and red light is reduced.

In addition, the organic electroluminescent device of the present invention can control the transmittance of blue light and red light by adjusting the blending of the mixed material, and thus control the power consumption of the pixels.

In this case, since the circular polarizing plate 200 of the present invention transmits light better than the conventional circular polarizing plate, when the circular polarizing plate 200 does not completely polarize the reflected light, the reflected light is more outward than the conventional reflected light. Emanates. That is, by using the circular polarizer 200 made of a dye-based material, the contrast of the organic EL device of the present invention can be reduced. Therefore, a method that can prevent the lowering of the contrast should be proposed.

In the organic electroluminescent device of the present invention, the insulating film 60 is formed of a black material in order to prevent a decrease in contrast.

The insulating film 60 is made of a black material. Alternatively, the insulating film 60 according to another embodiment of the present invention includes a black matrix layer made of a material in which at least one of an organic material, an inorganic material, and a polymer is mixed with a black material, for example, black carbon. .

That is, since the insulating film 60 has a black color, when the external light and the reflected light reflected from the metal electrode layer 120 are incident on the insulating film 60, the insulating film 60 is absorbed by the insulating film 60. As a result, the amount of reflected light reflected from the metal electrode layer 120 and emitted to the outside is reduced, so that the contrast of the organic EL device is improved.

In short, the organic EL device of the present invention can reduce power consumption while maintaining or improving contrast.

Hereinafter, the circular flat plate 200 will be described in detail.

The circular polarizer 200 includes a retarder 200b attached to the bottom of the substrate 10 and a linear polarizer 200a attached to the bottom of the retarder 200b.

The linear polarizer 200a is made of the mixed material and polarizes the reflected light. Here, the linear polarizer 200a is formed by extending the polarizer film and dyeing the mixed material on the extended polarizer film.

The retarder 200b has an angle of 45 ° with a central axis of the linear polarizer 200a and delays the phase of external light passing through the linear polarizer 200a by λ / 4 (λ is a wavelength).

As shown in FIG. 2B, in the organic electroluminescent device of the present invention, the transmittance of the circular polarizer 200 for blue light and red light is about 50% or more, and the transmittance of the circular flat plate 200 for green light. Is about 45% to 50%. Here, the central wavelength of blue light is about 460 nm, the central wavelength of green light is about 520 nm, and the central wavelength of red light is about 620 nm.

3A and 3B illustrate a process of blocking reflected light by using a circular polarizer according to an exemplary embodiment of the present invention.

Referring to FIG. 3A, unpolarized external light is incident on the linear polarizer 200a.

At this time, the transmission axis of the linear polarizing plate 200a is formed in the vertical direction, so that only light in the vertical direction of the external light passes through the linear polarizing plate 200a.

Subsequently, external light that has passed through the linear polarizer 200a is incident on the retarder 200b, so that the external light is changed to a circularly polarized state with a delay of? / 4. This is because the central axis of the retarder 200b forms an angle of 45 ° with the central axis of the linear polarizer 200a.

Subsequently, the external light passing through the retarder 200b is reflected by the metal electrode layer 120, and the reflected light passes through the retarder 200b again.

As a result, the reflected light in the circularly polarized state is changed into the linearly polarized state. However, the reflected light passing back through the retarder 200b is perpendicular to the external light that has not passed through the retarder 200b at all. This is because the external light is delayed by [lambda] / 4 every time it passes through the retarder 200b, i.e., it has been delayed by [lambda] / 2 since it passed twice.

Subsequently, the reflected light in the linearly polarized state is incident on the linear polarizer 200a, and then disappears. This is because the reflected light in the linearly polarized state and the transmission axis of the linear polarizer 200a are perpendicular to each other, so that the reflected light in the linearly polarized state is all polarized.

Referring to FIG. 3B, unpolarized external light is incident on the linear polarizer 200a.

At this time, the absorption axis of the linear polarizer 200a is formed in the vertical direction, so that only light in the horizontal direction of the external light passes through the linear polarizer 200a.

Subsequently, external light passing through the linear polarizer 200a passes through the retarder 200b. As a result, as shown in FIG. 3B, a circular polarization state is performed and the inside of the organic EL device is advanced.

Subsequently, the advanced external light is reflected from the metal electrode layer 120 and passes through the retarder 200b again.

Subsequently, the reflected light passing through the retarder 200b is incident on the linear polarizing plate 200a, so that all of them are polarized and extinguished.

As shown in FIGS. 3A and 3B, external light is dissipated by passing through the circular polarizer 200 twice. Therefore, compared with the organic electroluminescent element which does not have a circular polarizing plate, the contrast of the organic electroluminescent element of this invention becomes high.

Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art having ordinary knowledge of the present invention will be able to make various modifications, changes, additions within the spirit and scope of the present invention, such modifications, changes and Additions should be considered to be within the scope of the following claims.

As described above, the organic electroluminescent device according to the present invention uses a circular polarizing plate made of a mixed material in which a dye-based material and an iodine-based material are mixed, thereby reducing power consumption.

In addition, since the organic EL device according to the present invention uses an insulating film containing a black material, there is an advantage that the contrast of the organic EL device is improved.

Claims (4)

In the organic electroluminescent device in which an indium tin oxide layer, an organic material layer and a metal electrode layer are sequentially formed on the upper surface of the substrate, An insulating layer formed on the indium tin oxide layer and including a black material; And It is attached to the surface of the substrate opposite to the upper surface on which the indium tin oxide layer is formed to polarize light incident from the outside, and comprises a circular polarizing plate made of a mixed material mixed with a dye-based material and an iodine-based material An organic electroluminescent element having a polarizing plate to be. The method of claim 1, wherein the circular polarizing plate, A retarder attached to a surface of the substrate opposite to an upper surface on which the indium tin oxide layer is formed and retarding a phase of incident light; And The organic electroluminescent device having a polarizing plate attached to the surface of the retarder opposite to the substrate, comprising a linear polarizing plate made of the mixed material. The organic electroluminescent device having a polarizing plate according to claim 1 or 2, wherein the circular polarizing plate selectively further transmits light having a specific wavelength among the light generated from the organic material layer. The method of claim 3, wherein the circular polarizing plate is passed through the red light and blue light of the light emitted from the organic layer with a transmittance of 50% or more, characterized in that the green light passes with a transmittance of 45% to 50%. An organic electroluminescent element having a polarizing plate.

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