JPH1140362A - Electroluminescent device and method of manufacturing the same - Google Patents

Abstract

(57) [Problem] To provide an electroluminescent element free from uneven brightness and a method for manufacturing the same. SOLUTION: An organic EL panel 1 has an anode electrode 11, a low-resistance metal electrode 12, an organic EL layer 13, and a cathode electrode 14 laminated on a transparent glass substrate 10. The anode electrode 11 is made of ITO,
Large sheet resistance. A low resistance metal electrode 12 is provided on the peripheral end of the anode electrode 11. The low resistance metal electrode 12 has a small sheet resistance. The organic EL layer 13 becomes thinner as the distance from the low-resistance metal electrode 12 increases. The voltage applied from the anode electrode extraction terminal 11 a hardly causes a voltage drop at the low-resistance metal electrode 12, but causes a voltage drop at the anode electrode 11. As a result, the organic EL layer 13 emits light having substantially the same brightness throughout the organic EL panel 1 because the organic EL layer 13 is thinner at the central portion where the voltage between the anode and the cathode is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescent device and a method of manufacturing the same, and more particularly, to an electroluminescent device which does not cause uneven brightness even when the area is increased, and a method of manufacturing the same.

[0002]

2. Description of the Related Art An organic EL (electroluminescence) panel is known as a backlight of a flat display such as a liquid crystal display. Conventionally, an organic EL panel 3 used as a backlight includes, for example, an anode electrode 31, an organic EL layer 32, and a cathode electrode 33 laminated on a transparent glass substrate 30, as shown in FIG. Was composed of At one end of the anode electrode 31, an anode electrode extraction terminal 31a is provided. At one end of the cathode electrode 33, a cathode electrode extraction terminal 33a is provided.

Here, the anode electrode take-out terminal 31a
A predetermined voltage is applied to each of the cathode electrode take-out terminals 33a and the anode electrode 31 of the organic EL panel 3.
By applying a predetermined voltage equal to or greater than a threshold value between the organic EL layer 32 and the cathode electrode 33, a current flows through the organic EL layer 32, and energy generated by recombination of electrons and holes is transferred to the organic EL layer 3.
2 emits light when absorbed by the light emitting layer.

The light emitted from the organic EL layer 32 passes through the anode electrode 31 and the glass substrate 30 and is displayed. Therefore, the anode electrode 31 is generally made of transparent ITO.
(Indium Tin Oxide), and for the cathode electrode 33, a reflective low-resistance Mg (Magnesium) alloy is used.

[0005] However, the ITO constituting the anode electrode 31 has a higher resistance than the cathode electrode 33, and the applied voltage decreases as the distance from the anode electrode take-out terminal 31a increases. Therefore, the anode electrode 31
The voltage between the cathode electrode 33 and the anode electrode 33 decreases as the distance from the anode electrode extraction terminal 31a increases, and the current flowing through the organic EL layer 32 decreases. For this reason, in the conventional organic EL panel 3, there was a problem that the brightness could be uneven depending on the distance from the anode electrode extraction terminal 31a.

In order to solve the uneven brightness of the organic EL panel 3 due to the voltage drop at the anode electrode 31, it is conceivable to form the anode electrode 31 thick. That is, by forming the anode electrode 31 thick, the resistance value of the anode electrode 31 is reduced, and a voltage drop at the anode electrode 31 is prevented.

However, when the anode electrode 31 is formed thick to reduce the resistance, the amount of light absorbed by the anode electrode 31 out of the light emitted from the organic EL layer 32 increases. In particular, when the anode electrode 31 has a thickness longer than the wavelength of light emitted from the organic EL layer 32, light absorption is increased, and therefore, there is a problem that light displayed on the organic EL panel 3 becomes dark. Was.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and has as its object to provide an electroluminescent device free from uneven brightness and a method for manufacturing the same.

[0009]

In order to achieve the above object, an electroluminescent device according to a first aspect of the present invention is provided to face a first electrode and a second electrode for applying a voltage. A second electrode (14) having a lower sheet resistance value than the first electrode, provided between the first and second electrodes, and provided between the first and second electrodes. A light-emitting layer having a light-emitting region that emits light at a luminance according to the voltage and the thickness thereof, wherein the light-emitting layer has a different thickness in a layer thickness direction so that the luminance of the light-emitting region is uniform. It is characterized by.

Here, the second electrode has a lower sheet resistance than the first electrode. In other words, the second electrode is made of a material having a lower resistance in the thickness direction, or is made of the same material. This is achieved by increasing the thickness and / or width of the material. Based on this low resistance value, the variation in the voltage applied from the second electrode to the light emitting region of the light emitting layer is uniform such that the light emission luminance does not vary. It is desirable that

According to this electroluminescent device, the potential at the first electrode changes according to the light emitting region due to the voltage drop at the first electrode, and the potential between the first and second electrodes in each light emitting region changes. Even if the voltage of the light emitting layer changes, the thickness of the light emitting layer is changed in accordance with the change, so that the light emission luminance does not change. For this reason, this electroluminescent element emits light with uniform brightness even when the area is increased, for example, when used as a backlight of a flat display such as a liquid crystal display, and does not cause uneven brightness. .

The electroluminescent device further includes a low resistance peripheral electrode formed on a peripheral portion of the first electrode, and the light emitting layer changes its thickness according to a distance from the peripheral electrode. Things.

As described above, the voltage at the low-resistance peripheral electrode formed at the peripheral portion of the first electrode hardly changes depending on the location. Therefore, the change in the voltage at the first electrode can be determined by the distance from the peripheral electrode. For this reason, for example, the light emitting layer can be made thicker at the periphery and thinner at the center, so that when the light emitting layer is formed, it is easy to change the thickness depending on the location so that uneven brightness does not occur. become. At this time, the peripheral electrode may be formed continuously on the entire peripheral edge of the light emitting layer or may be formed intermittently on the peripheral edge.

In the above-mentioned electroluminescent device, it is preferable that the first electrode is formed of a transparent member, and the second electrode and the peripheral electrode are formed of a low-resistance metal.

That is, in order to emit the light emitted from the light emitting layer to the outside, one of the electrodes is made of a transparent member,
It is desirable to use a metal having reflectivity. Here, the low-resistance metal used as the second electrode includes M
There are various metals with low sheet resistance such as g and Ti,
Since it is a metal, it has reflectivity to visible light. On the other hand, transparent members used as electrodes are made of IT
O is generally used, but has a relatively high sheet resistance and easily causes a voltage drop as compared with metals such as Mg and Ti. IT
To prevent a voltage drop at the electrode composed of O,
The electrodes may be thickened, but this reduces the amount of emitted light. For this reason, by forming the peripheral edge resistor with a low-resistance metal, it is possible to prevent a voltage drop in the first electrode in a considerable range without reducing the amount of emitted light.

In the above electroluminescent device, the light emitting layer may be constituted by, for example, an organic electroluminescent layer.

In order to achieve the above object, a method for manufacturing an electroluminescent device according to a second aspect of the present invention comprises a first electrode forming step of forming a first electrode on a substrate, and By using a mask provided with a floating mask portion and passing a step of depositing a light emitting layer material from a window provided in the mask,
A light emitting layer forming step of forming a light emitting layer having a different thickness depending on a light emitting region on the first electrode formed in the first electrode forming step, and a light emitting layer formed on the light emitting layer formed in the light emitting layer forming step And a second electrode forming step of forming a second electrode.

In the method of manufacturing an electroluminescent device, in the step of vapor-depositing the light-emitting layer material, the vaporization is performed in a gap between the floating mask portion and the first electrode formed in the first electrode forming step. The semiconductor material thus wraps around. The amount of this semiconductor material wrapping around decreases as the distance from the window increases. Therefore, a light emitting layer having a different thickness depending on the light emitting region can be easily formed.

In the manufacturing process of the electroluminescent device, the light emitting layer forming step is performed by repeating a step of forming a light emitting layer a plurality of times using a plurality of masks having different shapes of a floating mask portion and a window. A light-emitting layer can be formed.

In this case, even when an electroluminescent device having a large area is formed, it is easy to change the thickness of the light emitting layer according to the light emitting region.

In the above-mentioned manufacturing process of the electroluminescent device, the first electrode is an anode electrode of the organic electroluminescence device, and the second electrode is a cathode electrode of the organic electroluminescence device. The light emitting layer is an organic electroluminescent layer of the organic electroluminescent device having a hole transport layer and an electron transport layer, and the light emitting layer forming step uses the mask to form the positive electrode having a thickness different depending on a location. The method may include a first step of forming a hole transport layer and a second step of sequentially forming the electron transport layer in a predetermined arrangement.

[0022]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In this embodiment, a case will be described in which the present invention is applied to an organic EL panel used as a backlight of a portable information terminal including a liquid crystal panel.

FIG. 1 is a diagram schematically showing the configuration of the organic EL panel 1 of this embodiment, and FIG. 2 is a sectional view of the organic EL panel 1 taken along line AA of FIG. As shown in the figure, the organic EL panel 1 is formed by sequentially stacking an anode electrode 11, a low-resistance metal electrode 12, an organic EL layer 13, and a cathode electrode 14 on a transparent glass substrate 10.

The anode electrode 11 is formed on the glass substrate 10 by a photolithography method. The anode electrode 11 is made of transparent ITO having a thickness of 2200 ° and transmits light emitted from the organic EL layer 13. The sheet resistance of the anode electrode 11 is 8Ω / □. At one end of the anode electrode 11, an anode electrode take-out terminal 11a for applying a voltage to the anode electrode 11 is provided.

The low resistance metal electrode 12 is connected to the anode electrode 11
Is formed by a vacuum deposition method on the peripheral portion of the substrate. The low-resistance metal electrode 12 is made of Mg or a Mg alloy, and prevents a voltage drop of the voltage applied from the anode electrode extraction terminal 11a even in a portion far from the anode electrode extraction terminal 11a.

The organic EL layer 13 emits white light for use as a backlight by vacuum evaporation to form three types of organic E layers for red (R), green (G), and blue (B).
A plurality of L layers are formed in a predetermined order. Organic EL layer 13
As shown in FIG. 3, a hole transport layer 13a is commonly formed on the anode electrode 11 for R, G, and B. The hole transport layer 13a, as shown in FIG.
It is formed by changing the layer thickness so that the layer thickness differs according to the distance from the substrate. On the hole transporting layer 13a, an electron transporting light emitting layer 13r for R and an electron transporting light emitting layer 13 for G
The light emitting layer 13ba and the electron transporting layer 13bb for g and B are formed in a predetermined order.

The hole transport layer 13a common to R, G, and B has an α
-Consisting of NPD. The electron transporting light emitting layer 13r for R is
DCM1 consists of dispersed Alq3. The electron transporting light emitting layer 13g for G is made of Bebq2. The light emitting layer 13ba for B is composed of 96% by weight of DPVBi and 4% by weight of B
CzVBi. The electron transport layer 13bb for B is made of A
1q3. These electron transporting light emitting layer or electron transporting layer and light emitting layer, by using a mask,
R, G, and B are sequentially formed.

When a voltage higher than a threshold value is applied between the anode electrode 11 and the cathode electrode 14, the hole transport layer 13
a is injected into the electron transporting light emitting layer 13r,
Electrons are injected from 3g or the electron transport layer 13bb. The energy excited by the recombination of the holes and the electrons is absorbed by the electron-transporting light-emitting layers 13r, 13g or the light-emitting layer 13ba, thereby emitting R, G, and B light, respectively. Organic EL panel 1
R, G, and R emitted from the respective organic EL layers for R, G, and B
The white light is emitted when the three colors B are additively mixed. At this time, the light emitting region is a portion where the anode electrode 11 and the cathode electrode 14 of the organic EL layer 13 overlap.

By forming the hole transport layer 13a so that the layer thickness varies depending on the distance from the low resistance metal electrode 12,
The thickness of the entire organic EL layer 13 differs depending on the distance from the low-resistance metal electrode 12. That is, the central region (a) where the distance from the low-resistance metal electrode 12 is longer.
Then, the layer thickness of the organic EL layer 13 is about 900 °.
On the other hand, in the region (b) near the low resistance metal electrode 12, the layer pressure of the organic EL layer 13 is about 1000 °. As described above, the organic EL layer 1 depends on the distance from the low-resistance metal electrode 12.
By changing the layer thickness of No. 3, the voltage-luminance characteristics of the organic EL layer 13 differ from place to place.

The cathode electrode 14 is formed on the organic EL layer 13 by a vacuum deposition method. Cathode electrode 1
Numeral 4 is made of a low work function material such as Mg or Mg alloy having a thickness of 5500 ° and reflects light emitted from the organic EL layer 13. The sheet resistance of the cathode electrode 14 is 0.3Ω / □
It is. On one end of the cathode electrode 14, on the diagonal side of the anode electrode extraction terminal 11 a, a cathode electrode extraction terminal 14 a for applying a voltage to the cathode electrode 14 is provided.

As described above, the organic EL panel 1 is used as a backlight of a liquid crystal display of a portable information terminal, and the area of a portion (display area) through which light passes through the glass substrate 10 is 6 ×. It is about 9cm. In addition, the thickness of the organic EL layer 13 of the organic EL panel 1 varies depending on the distance from the low-resistance metal electrode 12, and the voltage-
The luminance characteristics are shown in FIG. 4A in the area (a), and in the area (b) in the area (a).
Then, the result is as shown in FIG.

This organic EL panel 1 has a glass substrate 10
An anode electrode 11, a low resistance metal electrode 12, an organic EL layer 13, and a cathode electrode 14 were formed on the substrate.
These are actually sealed by a sealing member (not shown).

Hereinafter, the organic EL panel 1 of this embodiment will be described.
Will be described with reference to FIGS. 5 (A) to 5 (F). Here, according to the cross section taken along the line AA in FIG.
The manufacturing process of the L panel 1 will be described sequentially.

First, an ITO thin film is deposited on the entire surface of the glass substrate 10 by a sputtering method. Then, an unnecessary portion of the deposited ITO, that is, a peripheral portion excluding a portion of the anode electrode extraction terminal 11a is removed by a photolithography method. Thereby, the anode electrode 11 is formed on the glass substrate 10 (step (A)).

Next, using a metal mask having a window at the periphery of the anode electrode 11 formed in the step (A), Mg or a Mg alloy is vacuum deposited to form a low-resistance metal electrode 12 ( Step (B)).

Next, using the metal mask 2, α-N
PD is vacuum deposited. FIG. 6A is a plan view of the metal mask 2, and FIG. 6B is a sectional view taken along line BB of FIG. 6A. The metal mask 2 used here is shown in FIGS.
As shown in the figure, a planar mask portion 2a and a planar mask portion 2a
And a floating mask portion 2b formed at a different height and a window 2c. When vacuum deposition is performed using the metal mask 2, the evaporated α-NPD enters through the window 2c and deposits on the window 2c. In addition, since there is a gap between the anode electrode 11 formed in the step (A) and the floating mask portion 2b, the evaporated α-NPD enters this gap and is deposited. Here, the amount of wraparound α-NPD decreases as the distance from the window increases. This allows
An α-NPD layer having a predetermined inclination, that is, a part of the hole transport layer 13a is formed (step (C)).

Next, using a metal mask having only a window without a floating mask portion, a metal mask having only windows was formed on the anode electrode 11 formed in the step (A) and the α-NPD layer formed in the step (C). Then, α-NPD is vacuum-deposited to form the entire hole transport layer 13a (step (D)).

Next, using a metal mask having a window opened in accordance with the arrangement of the portion where the light emitting layer 13ba for B is to be formed, the hole transport layer 13a formed in the steps (C) and (D) was used. DPVBi and BCzVBi are mixed at a predetermined ratio on the blue coloring region and vacuum-deposited to form a B light emitting layer 13ba. Then, using the same metal mask,
The electron transport layer 13bb for B is formed by vacuum-depositing q3. Further, the hole transport layer 1 formed in the steps (C) and (D) is formed using a metal mask having a different window arrangement.
Alq in which DCM1 is dispersed on the red coloring region 3a
3, and Bebq2 was vacuum-deposited on the green coloring region,
And G electron transporting light emitting layers 13r and 13g are formed. Thereby, the entire organic EL layer is formed (step (E)).

Next, on the electron transporting light emitting layers 13r and 13g or the electron transporting layer 13bb formed in the step (E), the area is slightly smaller than these layers, and the area of the cathode electrode extraction terminal 14a is formed. Also, the cathode electrode 14 is formed using a metal mask having an opened window (step (F)).

Then, the anode electrode 11, the low-resistance metal electrode 12, the organic EL layer 13, and the cathode electrode formed in the above steps (A) to (F) are sealed with a sealing member.
The organic EL panel 1 is manufactured (this step is not shown).

Hereinafter, the organic EL panel 1 of this embodiment will be described.
Will be described. In order to make the organic EL panel 1 emit light, the anode electrode take-out terminal 11a and the cathode electrode take-out terminal 1 are set such that the supply voltage in the thickness direction of the organic EL layer 13 in the region (b) becomes approximately 4V.
A predetermined voltage is applied from a driver (not shown) to the terminal 4a. Here, a voltage of 4 V is applied to the anode electrode extraction terminal 11a and a voltage of 0 V is applied to the cathode electrode extraction terminal 14a.

The voltage applied to the anode electrode extraction terminal 11a is also applied to the low resistance metal electrode 12. Since the low-resistance metal electrode 12 has a small resistance, even if a current flows through the organic EL layer 13, the applied voltage hardly drops, and the potential of the low-resistance metal electrode 12 becomes almost 4 V on the entire surface. Since the anode electrode 11a has a large sheet resistance of 8Ω / □, the voltage of 4 V at the portion in contact with the low-resistance metal electrode 12 decreases as the current flows through the organic EL layer 13 as the distance from the low-resistance metal electrode 12 increases. . And
The voltage in the central region (a) of the anode electrode 11a is:
It becomes almost 3.6V. On the other hand, in the region (b), the voltage does not drop so much, and the voltage becomes almost 4V.

On the other hand, the voltage applied to the cathode electrode take-out terminal 14a is such that the sheet resistance of the cathode electrode 14 is equal to 0.
Since it is as small as 3 Ω / □, it hardly changes due to the current flowing through the organic EL layer 13 in the cathode electrode 14. That is, the voltage of the entire cathode electrode 14 is almost 0 V
Becomes

As a result, the voltage between the anode electrode 11 and the cathode electrode 14 is about 3 in the region (a).
6 V, and about 4 V in the region (b). Therefore, as shown in the voltage-luminance characteristic diagrams of FIGS. 4A and 4B, the organic EL panel 1 has a region (a) of about 560 cd / m 2.
^At a luminance of ² , light is emitted at a luminance of about 560 cd / m ² even in the area (b).

The voltage between the anode electrode 11 and the cathode electrode 14 in a region between the region (a) and the region (b) takes a value between 3.6 V and 4 V.
The thickness of the L layer 13 is also between those thicknesses. For this reason, the light emission luminance in regions other than the region (a) and the region (b) is also set to a thickness that is approximately 560 cd / m ² , which is almost the same as the light emission luminance in the region (a) and the region (b).

As described above, the organic EL panel 1 of this embodiment emits light with almost the same luminance at any place in the display area by changing the thickness of the organic EL layer 13 according to the voltage drop. . For this reason, uneven brightness due to a difference in the location of the organic EL panel 1 does not occur. The organic EL panel 1 of this embodiment does not cause uneven brightness even when the area is increased, and thus is suitable for use as a backlight of a flat display such as a liquid crystal display.

Further, the organic EL panel 1 of this embodiment
Then, M is provided on the periphery of the anode electrode 11 made of ITO.
A low-resistance metal electrode 12 made of g or Mg alloy is provided. Here, in the low resistance metal electrode 12, the voltage applied from the anode electrode extraction terminal 11a hardly drops. For this reason, since the voltage drop due to the anode electrode 11 is determined by the distance from the low-resistance metal electrode 12, the thickness of the organic EL layer 13 is thin at the center, and
The periphery can be thicker. Further, by providing the low-resistance metal electrode 12, even if the anode electrode 11 made of ITO is formed thin, a voltage drop can be prevented in a considerable portion, and the luminance of emitted light can be increased.

The organic EL panel 1 of this embodiment
Of the floating mask portion 2 of the metal mask 2
b and the formed anode electrode 11, α-NPD
Is wrapped around and vacuum-deposited, so that the thickness of the hole transport layer 13a and thus the thickness of the organic EL layer 13 can be easily changed.

In the above embodiment, the low-resistance metal electrode 12 made of Mg or Mg alloy is formed on the periphery of the anode electrode 11 made of ITO. The organic EL layer 13 according to the distance from the low resistance metal electrode 12
Had decided the thickness. However, even if a low resistance metal electrode is not formed on the anode electrode, as the distance from the cathode electrode extraction terminal increases, that is, as the voltage drop occurs at the anode electrode, the organic EL layer 1
3 may be made thinner.

In the above embodiment, the anode electrode 11 made of ITO is formed on the glass substrate 10 and
The light emitted from the layer 13 is applied to the anode electrode 11 and the glass substrate 1.
0 was displayed in a transparent manner. However, the anode electrode made of ITO may be formed farther from the substrate than the cathode electrode. In this case, after the electron transporting light emitting layer or the electron transporting layer and the light emitting layer are formed on the cathode electrode made of Mg or Mg alloy formed on the substrate side, holes having different layer thicknesses depending on regions are formed using a metal mask. What is necessary is just to form a transport layer. Then, a low-resistance metal electrode made of Mg or a Mg alloy may be formed on the periphery of the hole transport layer, and an anode electrode made of ITO may be formed thereon. In this case, the light emitted from the organic EL layer passes through the anode electrode and is displayed on the opposite side of the substrate.

In the above embodiment, the anode electrode 11
Transparent ITO, and Mg or Mg
Low resistance metals such as alloys were used. However,
You may use ITO for a cathode electrode, and low resistance metal for an anode electrode. Also in this case, the light emission luminance in the organic EL panel can be made uniform by the layer thickness of the low resistance metal electrode and the organic EL layer provided on the periphery of the cathode electrode. The cathode electrode and the low-resistance metal electrode have Ti
(Titanium) or other low sheet resistance Mg or Mg
Other metals besides alloys can be used.

In the above embodiment, the organic EL panel 1
In addition, three types of organic EL layers of R, G, and B are arranged in a predetermined order, and white light is displayed by additive color mixing of the three colors of R, G, and B. Thus, the three types of organic E of R, G, and B
Instead of disposing the L layer, the present invention can also be applied to an electroluminescent element having a layer that emits white light. Also,
An organic EL panel that emits white light can be formed by arranging three types of organic EL panels for R, G, and B in an overlapping manner. In this case, the thickness of the organic EL layer can be changed for each of the R, G, and B organic EL panels as described above. Further, the present invention can be applied not only to an element emitting white light but also to an electroluminescent element emitting light of any color.

In the above embodiment, the organic EL panel 1
In order to make the layer thickness of the hole transport layer 13a different according to the distance from the low-resistance metal electrode 12, the metal mask 2 provided with the floating mask portion 2b was used (step (C) in FIG. 5).
In this step, the hole transport layer 13a may be formed through a plurality of steps using a plurality of metal masks having different shapes. In this case, even if the organic EL panel has a large area, it is easy to change the thickness of the hole transport layer 13a depending on the location.

In the above embodiment, the floating mask portion 2b
The thickness of the hole transport layer 13a is changed depending on the location by using the metal mask 2 provided with. However, the method for varying the thickness of the hole transport layer depending on the location is not limited to this. For example, by using multiple metal masks with different window positions and sizes, and through multiple steps of vacuum deposition using each metal mask,
The layer thickness of the hole transport layer 13a may be varied according to the distance from the low resistance metal electrode 12.

In the above embodiment, the case where the present invention is applied to the organic EL panel 1 used as a backlight of a portable information terminal having a liquid crystal panel has been described. However, the present invention can also be used for an organic EL element used for another purpose that emits light by applying a predetermined voltage between the electrodes. Further, the present invention can be applied to other light-emitting elements, such as an inorganic EL element, which emit light by an electric field and change the amount of light emission depending on the layer thickness between the electrodes even when the same voltage is applied between the electrodes. Further, the size can be applied to various sizes.

[0056]

As described above, according to the electroluminescent device of the present invention, luminance unevenness does not occur due to the voltage drop of the voltage applied to the electrode.

Further, by providing a peripheral electrode having a low resistance at the peripheral portion of the electrode, a voltage change due to a voltage drop at the electrode can be substantially determined by a distance from the peripheral electrode. Therefore, for example, the thickness of the light emitting layer can be made thicker at the peripheral portion and thinner at the center portion, so that it is easy to form a light emitting layer having a different thickness depending on the location so that uneven brightness does not occur. become.

According to the method of manufacturing an electroluminescent device of the present invention, by using a mask provided with a floating mask portion,
Since the light-emitting layer can be sunk into the region of the floating mask from the window, a light-emitting layer having a different thickness depending on a location can be easily formed.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of an organic EL panel according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line AA of the organic EL panel of FIG.

FIG. 3 is a diagram showing the structure of three types of organic EL layers of red, green and blue for generating white light in the organic EL layer of the organic EL panel of FIG. 1;

FIGS. 4A and 4B are diagrams showing voltage-luminance-efficiency characteristics of the organic EL panel of FIG. 1, in which FIG.
(B) is in the area (b).

FIG. 5 is an explanatory diagram of a manufacturing process of the organic EL panel of FIG. 1;

6A and 6B are diagrams showing a configuration of a metal mask used in a step (C) of FIG. 5, wherein FIG. 6A is a plan view and FIG.
FIG. 7 is a sectional view taken along line BB of FIG.

FIG. 7 is a diagram schematically showing a configuration of a conventional organic EL panel.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Organic EL panel, 10 ... Glass substrate, 11 ... Anode electrode, 11a ... Anode extraction terminal, 1
2 ... low resistance metal electrode, 13 ... organic EL layer, 13a ...
Hole transport layer, 13r, 13g ... Electron transporting light emitting layer, 1
3ba: light emitting layer, 13bb: electron transport layer, 14: cathode electrode, 14: cathode electrode extraction terminal, 2 ...
Metal mask, 2a: flat mask portion, 2b: floating mask portion, 2c: window

Claims (7)

[Claims] A first electrode provided with a first terminal for applying a voltage, and a second terminal provided opposite to the first electrode for applying a voltage. A second electrode (14) exhibiting a lower sheet resistance value than the first electrode; and a second electrode (14) provided between the first and second electrodes, and a voltage between the first and second electrodes and a thickness thereof. A light-emitting layer having a light-emitting region that emits light at an appropriate luminance. The light-emitting layer has a different thickness in a layer thickness direction so that the luminance of the light-emitting region is uniform. element. 2. A low-resistance peripheral electrode formed on a peripheral portion of the first electrode, wherein the thickness of the light-emitting layer is changed according to a distance from the peripheral electrode. The electroluminescent device according to claim 1. 3. The first electrode according to claim 1, wherein the first electrode is formed of a transparent member, and the second electrode and the peripheral electrode are formed of a low-resistance metal. 4. The electroluminescent device according to claim 1. 4. The electroluminescent device according to claim 1, wherein the light emitting layer is constituted by an organic electroluminescence layer. 5. A first electrode forming step of forming a first electrode on a substrate, and using a mask partially provided with a floating mask portion, evaporating a light emitting layer material from a window provided in the mask. A light emitting layer forming step of forming a light emitting layer having a different thickness depending on a light emitting region on the first electrode formed in the first electrode forming step; A second electrode forming step of forming a second electrode on the light-emitting layer described above. 6. The light emitting layer forming step is to form the light emitting layer by repeating a step of forming the light emitting layer a plurality of times using a plurality of masks having different floating mask portions and windows respectively. The method for manufacturing an electroluminescent device according to claim 5, wherein: 7. The organic electroluminescence device according to claim 1, wherein the first electrode is an anode electrode of the organic electroluminescence device, the second electrode is a cathode electrode of the organic electroluminescence device, and the light emitting layer is a hole transport layer. An organic electroluminescence layer of the organic electroluminescence element having an electron transport layer, wherein the light emitting layer forming step comprises: forming the hole transport layer having a thickness different from place to place using the mask. The method for manufacturing an electroluminescent device according to claim 5, comprising: a step; and a second step of sequentially forming the electron transport layer in a predetermined arrangement.