KR100774868B1 - Light Emitting Diodes and method for manufacturing thereof - Google Patents

Abstract

According to the present invention, a first electrode, a light emitting part formed on the first electrode, and a second electrode and a third electrode are formed on the light emitting part, and any one of the second electrode and the third electrode is formed on the outer edge portion. The work function of the second electrode and the third electrode is different from each other to provide an electroluminescent device.

EL, outer edge, work function

Description

Light emitting diodes and method for manufacturing the same

1 is a configuration diagram schematically showing a structure of an organic light emitting device as an example of the prior art.

FIG. 2 is a view showing an example in which an edge portion of a pixel is deteriorated when the cathode electrode shown in FIG. 1 is formed on a light emitting portion. FIG.

3 is a configuration diagram schematically showing the structure of an organic electroluminescent device as a first embodiment according to the present invention;

4 is a plan view showing in more detail the organic electroluminescent device shown in FIG.

FIG. 5 is a cross-sectional view of the organic electroluminescent device of FIG. 4 taken along the line AA '. FIG.

FIG. 6 is a rear view showing the structure of a cathode electrode of the organic electroluminescent device shown in FIG. 5; FIG.

7 to 9 are diagrams showing energy diagrams of the organic electroluminescent device shown in FIGS. 4 and 5.

FIG. 10 is a rear view of the modified embodiment of FIG. 3 and illustrates a structure of a cathode of an organic light emitting diode. FIG.

FIG. 11 is a schematic view illustrating the structure of an organic EL device according to another modified embodiment of FIG. 3.

12 is a configuration diagram schematically showing the structure of an organic electroluminescent device as a second embodiment according to the present invention.

FIG. 13 is a modified embodiment of FIG. 12 and schematically illustrates a structure of an organic EL device. FIG.

* Description of the main parts of the drawings *

300, 400, 500, 1100, 1200, 1300: organic electroluminescent device

301, 1101, 1201, 1301: substrate

303, 1103, 1203, 1303: first electrode

305, 1105, 1213, 1313: hole injection layer

307, 1107, 1211, 1311: hole transport layer

309, 1109, 1209, 1309: organic light emitting layer

311, 1111, 1207, 1307: electron transport layer

313, 1113, 1205, 1305: electron injection layer

315, 1015, 1115, 1204, 1304: second electrode

317, 1017, 1117, 1218, 1318: third electrode

318, 1018, 1118, 1206, 1306: cathode electrode

404: insulating film 406, 506: partition wall

408: light emitting unit P ₁ : pixel

P ₂ : Partial P ₃ , P ₅ : Center

P ₄ : All parts

The present invention relates to an electroluminescent device and a method of manufacturing the same.

Electroluminescent devices are largely classified into inorganic electroluminescent devices and organic electroluminescent devices according to the material of the light emitting layer. Self-luminous devices that emit light by themselves have fast response speed and high luminous efficiency, luminance, and viewing angle. have. Such organic light emitting diodes (Organic Emitting Light Diodes), which use organic materials among the electroluminescent devices, have a low DC driving voltage, can be thinned, uniformity of emitted light, easy pattern formation, and comparable to other light emitting devices. It has the advantages of luminous efficiency, all color light emission in the visible region, and is a technical field that is being actively researched for application to display elements.

Herein, the organic EL device may include a bottom emission method and a top emission method according to a direction in which light is emitted. In addition, organic EL devices are classified into passive matrix organic emitting diodes (PMOELD) and active matrix organic emitting diodes (AMOELD) according to a driving method. .

Looking at the structure of such an organic electroluminescent device schematically as shown in FIG.

1 is a configuration diagram schematically showing a structure of an organic EL device as an example of the related art.

As shown in FIG. 1, in the conventional organic electroluminescent device 100, an anode electrode 103 is formed on a substrate 101, and holes are formed on the anode electrode 103. The injection layer 105 was formed, and the hole transport layer 107 was formed on the hole injection layer 105.

In addition, an organic emission layer 109 is formed on the hole transport layer 107, an electron transport layer 111 is formed on the organic emission layer 109, and an electron injection layer 113 is formed on the electron transport layer 111. .

Finally, a cathode electrode 115 is formed on the electron injection layer 113.

One such conventional organic electroluminescent device 100 is provided in the pixel circuit unit 202 as shown in FIG. 2 when the cathode electrode 115 is unevenly deposited on the electron injection layer 113. Since the outer edge portion P ₂ of the plurality of pixels P ₁ is deteriorated earlier than the center portion P ₃ , the emission area emitted from the pixel P ₁ during electroluminescence is further reduced.

Accordingly, the luminance of the outer edge portion P ₂ is lower than the luminance of the center portion P ₃ during display, resulting in uneven luminance deviation of the pixel P ₁ , resulting in low luminous efficiency.

In order to solve the above problems, an object of the present invention is to provide an electroluminescent device capable of improving the luminous efficiency by widening the light emitting area by making the overall luminance uniform during display.

Another object of the present invention is to provide an electroluminescent device capable of preventing the deterioration of the electrode and lowering the power consumption due to the reduction of the resistance of the signal line to improve the life.

In order to achieve the above object, the present invention includes a first electrode, a light emitting part formed on the first electrode, and a second electrode and a third electrode formed on the light emitting part, and any one of the second electrode and the third electrode. Is formed at an outer edge portion, and the work functions of the second electrode and the third electrode are different from each other.

According to another feature of the invention, the second electrode is formed on the outer edge portion on the light emitting portion, the third electrode is formed to cover the second electrode, the work function of the third electrode is greater than the work function of the second electrode It is characterized by.

According to another feature of the invention, the second electrode is formed on the front surface on the light emitting portion, the third electrode is formed on the outer edge portion on the second electrode, the work function of the third electrode than the work function of the second electrode It is characterized by a small one.

According to another feature of the invention, the first electrode is Ag, Al, Ni, Pt, Ti, Cr, In ₂ O ₃ , ZnO, Al ₂ O ₃ , SnO ₂ Any one or any one or more alloys, and the second electrode and the third electrode include any one or any one or more of Li: Al, Mg, Ag, Ca, LiF, CsF, NaF, BaF ₂ .

According to another feature of the invention, the third electrode is formed on the outer edge portion on the substrate, the second electrode is formed to cover the third electrode, the work function of the second electrode is greater than the work function of the third electrode It is characterized by.

According to another feature of the invention, the third electrode is formed on the front surface on the substrate, the second electrode is formed on the outer edge portion on the third electrode, the work function of the second electrode is less than the work function of the third electrode It is characterized by.

According to another feature of the invention, the first electrode is any one or any one or more alloys of Ag, Al, Ni, Pt, Ti, Cr, In ₂ O ₃ , ZnO, Al ₂ O ₃ , SnO ₂ , The second electrode and the third electrode comprise any one or an alloy of any one of Li: Al, Mg, Ag, Ca, LiF, CsF, NaF, BaF ₂ .

According to another feature of the invention, the second electrode and the third electrode is characterized in that the cathode electrode.

According to another feature of the invention, the light emitting portion comprises an organic light emitting layer.

According to another feature of the invention, preparing a substrate, forming a first electrode on the substrate, forming a light emitting portion on the first electrode and the second electrode and the third electrode on the light emitting portion Forming an electrode of one of the second electrode and the third electrode on the outer edge portion, and forming a different work function of the second electrode and the third electrode.

According to another feature of the invention, the step of forming the second electrode and the third electrode, the second electrode is formed on the outer edge portion on the light emitting portion, the third electrode is formed so that the second electrode is covered, And forming the work function of the third electrode to be larger than the work function of the second electrode.

According to another feature of the invention, the step of forming the second electrode and the third electrode, the second electrode is formed on the front surface on the light emitting portion, the third electrode is formed on the outer edge portion on the second electrode, It is characterized in that the step of forming the work function of the three electrodes less than the work function of the second electrode.

According to still another aspect of the present invention, there is provided a method of preparing a substrate, forming a third electrode on the substrate, forming a second electrode on the third electrode, and forming a light emitting part on the second electrode. And forming a first electrode on the light emitting part, wherein any one of the second electrode and the third electrode is formed on the outer edge portion, and the work functions of the second electrode and the third electrode are different from each other. It is characterized by.

According to another feature of the invention, the step of forming the second electrode and the third electrode, the third electrode is formed on the outer edge portion on the substrate, the second electrode is formed so that the third electrode is covered, the second It is characterized in that the step of forming the work function of the electrode larger than the work function of the third electrode.

According to another feature of the invention, the step of forming the second electrode and the third electrode, the third electrode is formed on the entire surface on the substrate, the second electrode is formed on the outer edge portion on the third electrode, the second It is characterized in that the step of forming the work function of the electrode smaller than the work function of the third electrode.

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

<First Embodiment>

3 is a configuration diagram schematically showing the structure of an organic electroluminescent device as a first embodiment according to the present invention, and FIG. 4 is a plan view showing the organic electroluminescent device shown in FIG. 3 in more detail.

FIG. 5 is a cross-sectional view of the organic electroluminescent device of FIG. 4 taken along a line A to A ', and FIG. 6 is a rear view of the structure of the cathode of the organic electroluminescent device of FIG.

As shown in FIG. 3, the organic electroluminescent device 300 according to the present invention includes a substrate 301, a first electrode 303, a hole injection layer 305, a hole transport layer 307, and an organic light emitting layer 309. The electron transport layer 311, the electron injection layer 313, the second electrode 315, and the third electrode 317 are provided.

Here, the first electrode 303 is an anode electrode, and the second electrode 315 and the third electrode 317 represent the cathode electrode 318.

In the cathode electrode 318, a second electrode 315 is formed at an outer edge of the electron injection layer 313, and a third electrode 317 is formed to cover the second electrode 315. In this case, the work function of the third electrode 315 is formed to be relatively higher than the work function of the second electrode 317.

More specifically, as shown in FIGS. 4 to 6, the organic electroluminescent devices 400 and 500 according to the present invention are first formed on the substrate (301 of FIG. 4 and 301 of FIG. 5) such as ITO and IZO. An anode electrode (303 in Fig. 4, 303 in Fig. 5), which is one electrode, is formed, and between the anode electrodes (303 in Fig. 4, 303 in Fig. 5) on the anode electrode (303 in Fig. 4, 303 in Fig. 5). An insulating film (404 in Fig. 4, 404 in Fig. 5) is formed to insulate.

Thereafter, an insulating film (Fig. 4 404, 5 404) the on-pixel (Fig. 4, P _1, Fig. 5 of P ₁₎ to (406, Fig. 5 in Fig. 4 406), the partition wall to separate the two inverted trapezoidal And a hole injection layer (305 in FIG. 3, 305 in FIG. 5) and a hole transport layer (307 in FIG. 3, 307 in FIG. 5), which are formed in the form of a light emitting part (408 in FIG. 4 and 408 in FIG. 5). An organic light emitting layer (309 in FIG. 3, 309 in FIG. 5), an electron transport layer (311 in FIG. 3, 311 in FIG. 5), an electron injection layer (313 in FIG. 3, 313 in FIG. 5), and the like are sequentially formed.

Thereafter, the cathode electrode (318 in FIG. 3, 318 in FIG. 4, 318 in FIG. 5, and 318 in FIG. 6) is formed on the light emitting portion (408 in FIG. 4 and 408 in FIG. 5). And 315 of FIG. 5 and 315 of FIG. 6 and a third electrode (317 of FIG. 3, 317 of FIG. 5, and 317 of FIG. 6), and the second electrode (315 of FIG. 3 and 315 of FIG. 5). 315 6) are pixels (Fig. 4, P _1, also a portion of the outer edge portions of the P ₁₎ of 5 (formed in the P ₂₎ of Figure 5 of the P _2, FIG. 6, the third electrode (Fig. 3 317 5 and 317 of FIG. 6 are formed to cover the second electrode (315 of FIG. 3, 315 of FIG. 5, and 315 of FIG. 6).

At this time, the material of the first electrode (303 in Fig. 3, 303 in Fig. 4, 303 in Fig. 5) is Ag, Al, Ni, Pt, Ti, Cr, In ₂ O ₃ , ZnO, Al ₂ O ₃ , SnO ₂ It is formed of any one or at least one alloy of the material of the second electrode (315 in Figure 3, 315 in Figure 5, 315 in Figure 6) and the third electrode (317 in Figure 3, 317 in Figure 5, Figure 6 317) is formed of any one or more alloys of Li: Al, Mg, Ag, Ca, LiF, CsF, NaF, BaF ₂ .

Here, the second electrode (315 of FIG. 3, 315 of FIG. 5, and 315 of FIG. 6) has a work function relatively greater than that of the third electrode (317 of FIG. 3, 317 of FIG. 5, and 317 of FIG. 6). At least one lower layer may be formed to lower the sheet resistance of the cathode electrode 318 of FIG. 3, 318 of FIG. 4, 318 of FIG. 5, and 318 of FIG. 6.

Electrons formed at the time of electroluminescence by the cathode electrodes 318 of FIG. 3, 318 of FIG. 4, 318 of FIG. 5, and 318 of FIG. 6 provided in the organic EL device 400 and 500 according to the present invention. Looking at the process of (electron) hopping (electron) to the organic light emitting layer (hopping) as shown in Figs.

7 to 9 are diagrams illustrating an energy diagram of the organic electroluminescent device illustrated in FIGS. 4 and 5. First, in the drawings, electrons are represented by-, holes are represented by +, and electrons and holes are moved by arrows. In addition, Φ _A and Φ _C represent the work function of the anode electrode and the cathode electrode, EA and IP represent the electron affinity and ionization potential, respectively, and HOMO and LUMO represent the highest occupied molecular orbital valance band. And the Lowest Unoccupied Molecular Orbital conduction band. The principle in which the EL device emits light will be described with reference to the components shown in the drawings as follows.

As shown in FIG. 7, when the potential V _CA is not applied between the anode electrode 303 and the cathode electrode 318, the hole injection layer 305, the hole transport layer 307, the organic emission layer 309, The electron transport layer 311 and the electron injection layer 313 are in thermodynamic equilibrium, and the Fermi levels of the layers coincide with each other.

Meanwhile, as shown in FIG. 8, when the potential V _CA is applied between the two electrodes 303 and 318, holes (+) are gradually injected from the anode electrode 303 into the HOMO of the hole injection layer 305. The electron (−) is injected into the LUMO of the electron injection layer 313 from the cathode electrode 318. At this time, when the applied voltage V _CA is lower than the driving voltage or the turn-on voltage V _onset , holes (+) or electrons (−) do not move to the organic emission layer 309, and electroluminescence does not occur.

On the other hand, as shown in FIG. 9, when the applied voltage V _CA exceeds the turn-on voltage V _onset , holes (+) or electrons (−) are formed in the hole injection layer 305, the hole transport layer 307, Electroluminescence is generated by the electron injection layer 313 and the electron transport layer 311 being injected into the organic emission layer 309 to recombine holes (+) and electrons (−).

In this case, as described above with reference to FIG. 5, the cathode electrode 318 is made of a material having a relatively small work function, and the second electrode (315 of FIG. 3, 315 of FIG. 5, and 315 of FIG. 6) is a pixel (FIG. 4). of P _1, Fig. 5 of P ₁₎ the outer edge portion a part (5 in the P _2, It is formed on P ₂ of FIG. 6, and the work function is made of a material that is relatively higher than that of the second electrode (315 of FIG. 3, 315 of FIG. 5, and 315 of FIG. 6). 317 and 317 in Fig. 6 are formed to cover the second electrode (315 in Fig. 3, 315 in Fig. 5, 315 in Fig. 6).

The cathode electrode 318 is not only a role of an electrode but also an organic light emitting layer (309 of FIG. 3 and FIG. 5) of out-gassing existing inside the protective cap (not shown) and moisture and oxygen that are finely introduced into the inside. 309 is formed to primarily protect the deterioration.

As such, in the electroluminescent devices 400 and 500 according to the present invention, the cathode electrode 318 is formed using a mask (not shown), or the partition wall 406 of FIG. 4 is not used without the mask (not shown). the cathode electrode 318 is formed such that the pixel (P ₁₎ of P _1, of Figure 5 Figure 4 minutes using a 506 5).

At this time, the cathode electrode 318, which is typically formed by a mask (not shown) or a partition (406 in FIG. 4, 406 in FIG. 5), is a mask (not shown) and a partition (406 in FIG. 4, 406 in FIG. 5). Part of the outer border part located at (P _{2 in} FIG. 5, P ₂₎ the central portion of Fig. 6 (Fig. 5, P _3, do not uniformly deposited compared to P ₃₎ of Figure 6, of a portion of the outer edge portion (5 P _2, Degradation than 6 in the P ₂₎ the central part (Fig. 5 of P _3, P ₃ in FIG. 6) is started first.

Accordingly, a part of the outer border part (P ₂ of FIG. 5, Electron mobility of the P ₂₎ of FIG. 6 is slower than the electron movement of the central part (Fig. 5 of the P _3, 6 of the P ₃₎ to the luminance deviation occurs, caused a phenomenon that the luminous efficiency decreases do.

Accordingly, the present invention is to solve this problem, a part of the outer edge portion (P ₂ of FIG. 5, located in the mask (not shown) and the partition (406 in Figure 4, 406 in Figure 5)). The cathode electrode 318 having a low work function is further deposited in a region corresponding to P ₂ ) of FIG. 6 to prevent deterioration and to balance the density of the holes and the electrons.

Yiettara, of the present invention the pixel is a light emitting area which emits light (Fig of P _1, 5 P ₁ of 4) is widened, and the pixel (P _1, P ₁ in Fig. 5 in Fig. 4) at the time of display at the time of electroluminescent A part of the outer border portion (P ₂ of FIG. 5, Brightness with the central portion of the P ₂₎ of Fig. 6 (Fig. 5 of the P _3, it is possible not to be possible to equalize the luminance of the P ₃₎ of Figure 6 improves the quality of display without luminance variation there.

Furthermore, although not shown, when a scan signal is applied to a scan line (not shown) electrically connected to the cathode electrode 318 of FIG. 3, 318 of FIG. 4, 318 of FIG. 5, and 318 of FIG. 6, the cathode electrode (FIG. 3, 318 of FIG. 4, 318 of FIG. 5, and 318 of FIG. 6 are formed in two or more layers and formed of a material having a low work function, thereby preventing degradation and reducing power consumption due to reduced resistance of the scan line. It can be lowered to improve the life.

On the other hand, by varying the structure of the cathode electrode of the organic electroluminescent device according to the present invention it is possible to uniformize the luminance of the pixel without the luminance deviation, and improve the luminous efficiency. Same as

FIG. 10 is a rear view illustrating the structure of the cathode of the organic light emitting diode according to the modified embodiment of FIG. 3. First, although the organic electroluminescent device according to the present invention is not illustrated in the same manner as the organic electroluminescent device described above with reference to FIGS. 3, 4 and 5, the substrate (not shown) and the anode electrode as the first electrode (not shown) ), A hole injection layer (not shown), a hole transport layer (not shown), an organic light emitting layer (not shown), an electron transport layer (not shown), an electron injection layer (not shown) and the like.

Such components of the organic electroluminescent device according to the present invention, organic relations between them, and their respective functions are described with reference to the organic electroluminescent device (300 in FIG. 3 and 400 in FIG. 4). 5, the organic components and the organic relations between the components and the functions of the components 500 are the same as the descriptions thereof.

However, in the cathode electrode 1018 of the organic electroluminescent device according to the present invention, the second electrode 1015 is formed on the entire outer edge portion P ₄ of the third electrode 1017.

Such an organic EL device according to the present invention includes a field of pixels at the time of light emission (FIG. 4 P _1, Fig. 5 of P ₁₎ a light emitting area is widened, at the time of display pixels (4 emitted from P _1, The luminance of the entire portion P ₄ of the outer edge portion of P ₁ ) of FIG. 5 and the luminance of the central portion P ₅ can be made uniform, thereby improving the quality of the screen without variation in luminance.

Furthermore, although not shown, when a scan signal is applied to a scan line (not shown) electrically connected to the cathode electrode 318 of FIG. 3, 318 of FIG. 4, 318 of FIG. 5, and 318 of FIG. 6, the cathode electrode (FIG. 3, 318 of FIG. 4, 318 of FIG. 5, and 318 of FIG. 6 are formed in two or more layers and formed of a material having a low work function, thereby preventing degradation and reducing power consumption due to reduced resistance of the scan line. It can be lowered to improve the life.

On the other hand, by varying the structure of the cathode electrode of the organic electroluminescent device according to the present invention it is possible to uniformize the luminance of the pixel without luminance deviation, and improve the luminous efficiency. Looking at the organic electroluminescent device according to the present invention as shown in Figure 11 Same as

FIG. 11 is a schematic view illustrating the structure of an organic EL device according to another modified embodiment of FIG. 3. First, the organic electroluminescent device according to the present invention is the substrate, the first electrode, the hole injection layer, the hole transport layer, the organic light emitting layer, the electron transport layer, the electron injection layer, the second in the same manner as the organic electroluminescent device shown in FIG. An electrode and a 3rd electrode are provided.

More specifically, as shown in FIG. 11, in the organic electroluminescent device 1100 according to the present invention, a first electrode 1103 is formed on a substrate 1101, and a hole injection layer is formed on the first electrode 1103. 1105 is formed.

In addition, a hole transport layer 1107 is formed on the hole injection layer 1105, and an organic light emitting layer 1109 is formed on the hole transport layer 1107.

In addition, an electron transport layer 1111 is formed on the organic light emitting layer 1109, and an electron injection layer 1113 is formed on the electron transport layer 1111.

Finally, the second electrode 1115 is formed on the electron injection layer 1113 to the front, and the third electrode 1117 is formed on the outer edge of the second electrode 1115.

In the passive matrix organic electroluminescent device 1100 according to the present invention, the third electrode 1117 of the cathode electrode 1118 is a part of the outer edge portion of the second electrode 1115 (P _{2 in} FIG. 6) or The third electrode 1117 is formed on the entire portion (P ₄ of FIG. 10), and the work function is formed to be relatively lower than that of the second electrode 1115.

Yiettara, also similarly to the passive matrix type organic light emitting device shown in Figure 3, is a light emitting area wider that emits light when an electric field emission from the pixels (P _1, P ₁ in Fig. 5 in Fig. 4), the pixel at the time of the display (Fig. 4 of P _1, Fig. 5 of P ₁₎ the outer part of the edge portion (in Fig. 6 P ₂₎ or all of the parts (the brightness with the central portion of the P ₄₎ in Fig. 10 (Fig. 5 of the P _3, Fig. 6 P ₃ , P ₅ of FIG. 10 can be made uniform, and the quality of the screen can be improved without variation in luminance.

Furthermore, although not shown, when the scan signal is applied to a scan line (not shown) electrically connected to the cathode electrode 1118, the cathode electrode 1118 is formed in two or more layers and is formed of a material having a low work function. This prevents phenomena and lowers power consumption due to reduced resistance of the scan line, resulting in longer life.

On the other hand, by varying the structure of the cathode electrode of the organic electroluminescent device according to the present invention it is possible to uniformize the luminance of the pixel without luminance deviation, and improve the luminous efficiency. Looking at such an organic electroluminescent device according to the present invention Same as

Second Embodiment

12 is a configuration diagram schematically showing the structure of an organic electroluminescent device as a second embodiment according to the present invention.

As shown in FIG. 12, in the organic electroluminescent device 1200 according to the present invention, a third electrode 1203 is formed at an outer edge of the substrate 1201, and the second electrode 1203 is covered with the second electrode 1203. An electrode 1204 is formed.

In addition, an electron injection layer 1205 is formed on the second electrode 1204, an electron transport layer 1207 is formed on the electron injection layer 1205, and an organic emission layer 1209 is formed on the electron transport layer 1207. Is formed.

In addition, a hole transport layer 1211 is formed on the organic light emitting layer 1209, and a hole injection layer 1213 is formed on the hole transport layer 1211.

Finally, the first electrode 1218 is formed on the hole injection layer 1213.

In the organic electroluminescent device 1200 according to the present invention, the third electrode 1203 of the cathode electrode 1206 is formed on a part or the entire part of the outer edge portion of the substrate 1201, and the second electrode 1204. It is formed to cover the third electrode 1203. In this case, the third electrode 1203 is formed with a lower work function than the second electrode 1204.

Yiettara, similarly to the organic electroluminescent device shown in Figs. 3 and 11, the field-pixel at the time of light emission is a light emitting area which emits light at (Fig. 4 P _1, P ₁ in Fig. 5) is widened, and the pixel at the time of the display (Fig. 4 of P _1, Fig. 5 of the P of the outer rims of a portion (FIG. 6 of the ₁₎ P ₂₎ or the whole minute luminance and the central part (Fig. 5 (P ₄₎ of Fig. 10 of the _P-3, 6 P ₃ , P ₅ of FIG. 10 can be made uniform, and the quality of the screen can be improved without variation in luminance.

Although not shown, when the data signal is applied to a data line (not shown) electrically connected to the cathode electrode 1206, the cathode electrode 1206 is formed of two or more layers and a material having a low work function. It can prevent the phenomenon and lower the power consumption due to the reduced resistance of the data line, which also improves the service life.

On the other hand, by varying the structure of the cathode electrode of the organic electroluminescent device according to the present invention it is possible to uniformize the luminance of the pixel without luminance deviation, and improve the luminous efficiency. Same as

FIG. 13 is a modified embodiment of FIG. 12 and schematically illustrates a structure of an organic EL device. First, the organic EL device according to the present invention is provided in the same manner as the organic EL device described above with reference to FIG. 12. However, in the organic EL device according to the present invention, a third electrode is formed on the front surface of the substrate, and a second electrode having a relatively low work function is formed on the outer edge of the third electrode. Such an organic electroluminescent device according to the present invention will be described with reference to FIG. 13.

As shown in FIG. 13, in the organic electroluminescent device 1300 according to the present invention, a third electrode 1303 is formed on the front surface of the substrate 1301, and a second electrode 1300 is formed on the outer edge of the third electrode 1303. An electrode 1304 is formed.

In addition, an electron injection layer 1305 is formed to cover the second electrode 1304, an electron transport layer 1307 is formed on the electron injection layer 1305, and an organic emission layer 1309 on the electron transport layer 1307. Is formed.

In addition, a hole transport layer 1311 is formed on the organic light emitting layer 1309, and a hole injection layer 1313 is formed on the hole transport layer 1311.

Finally, the first electrode 1318 is formed on the hole injection layer 1313.

In the organic electroluminescent device 1300 according to the present invention, the second electrode 1304 of the cathode electrode 1306 is formed on a part or the entire part of the outer edge portion on the third electrode 1303. In this case, the second electrode 1304 is formed with a lower work function than the third electrode 1303.

Yiettara, similarly to the organic electroluminescent device shown in Fig. 3 and Figs. 11 and 12, a light emitting area for emitting light in the pixels (P _1, P ₁ in Fig. 5 in Fig. 4) when the light emitting is widened, at the time of display pixels (Fig. 4, P _1, Fig. 5 of P ₁₎ outside the edge portion part of the (in Fig. 6 P ₂₎ or around part of the (in Fig. 10 P ₄₎ brightness with the central portion (Fig. 5 of the P _3, Fig. The luminance of P ₃ of FIG. 6 and P ₅ of FIG. 10 can be made uniform, and the quality of the screen can be improved without variation in luminance.

In addition, although not shown, when the data signal is applied to a data line (not shown) electrically connected to the cathode electrode 1306, the cathode electrode 1306 is formed of two or more layers and a material having a low work function. It can prevent the phenomenon and lower the power consumption due to the reduced resistance of the data line, which also improves the service life.

Those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, the above-described embodiments are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims rather than the foregoing description, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

According to the electroluminescent device of the present invention made as described above and a method of manufacturing the same, the following effects can be obtained.

First, it is possible to improve the luminous efficiency by widening the light emitting area by making the overall luminance uniform during display.

Second, there is another effect that can prevent the deterioration of the electrode and improve the life by lowering the power consumption due to the reduction of the resistance of the signal line.

Claims (15)

A first electrode; A light emitting part formed on the first electrode; A second electrode and a third electrode are formed on the light emitting part, and any one of the second electrode and the third electrode is formed at an outer edge thereof, and the work functions of the second electrode and the third electrode are mutually different. Different, And the second electrode and the third electrode are cathode electrodes. The method of claim 1, The second electrode is formed on the outer edge portion of the light emitting portion, And the third electrode is formed to cover the second electrode, and the work function of the third electrode is larger than the work function of the second electrode. The method of claim 1, The second electrode is formed on the front surface on the light emitting portion, And the third electrode is formed at an outer edge portion of the second electrode, and the work function of the third electrode is smaller than the work function of the second electrode. The method of claim 1, The first electrode is Ag, Al, Ni, Pt, Ti, Cr, In ₂ O ₃ , ZnO, Al ₂ O ₃ , SnO ₂ Any one or any one or more alloys, The second electrode and the third electrode is an electroluminescent device comprising any one or at least one alloy of Li: Al, Mg, Ag, Ca, LiF, CsF, NaF, BaF ₂ . Board; A second electrode and a third electrode formed on the substrate; A light emitting part formed on the second electrode and the third electrode; And It includes a first electrode formed on the light emitting portion, Any one of the second electrode and the third electrode is formed on the outer edge portion of the front surface of the substrate, the work function of the second electrode and the third electrode is different from each other, And the second electrode and the third electrode are cathode electrodes. The method of claim 5, The third electrode is formed on the front surface on the substrate, And the second electrode is formed at an outer edge portion of the third electrode, and the work function of the second electrode is smaller than the work function of the third electrode. The method of claim 5, The first electrode is any one or any one or more alloys of Ag, Al, Ni, Pt, Ti, Cr, In ₂ O ₃ , ZnO, Al ₂ O ₃ , SnO ₂ , And the second electrode and the third electrode include any one or any one or more alloys of Li: Al, Mg, Ag, Ca, LiF, CsF, NaF, and BaF ₂ . The method of claim 5, The third electrode is formed on the outer edge portion of the substrate, And the second electrode is formed to cover the third electrode, and the work function of the second electrode is greater than the work function of the third electrode. The method according to claim 1 or 5, The light emitting part includes an organic light emitting layer. Preparing a substrate; Forming a first electrode on the substrate; Forming a light emitting part on the first electrode; A second electrode and a third electrode are formed on the light emitting part, and one of the second electrode and the third electrode is formed on the outer edge portion, and the work functions of the second electrode and the third electrode are mutually different. Forming differently, The second electrode and the third electrode is a method of manufacturing an electroluminescent device, characterized in that the cathode electrode. The method of claim 10, Forming the second electrode and the third electrode, The second electrode is formed on the outer edge portion of the light emitting portion, And forming the third electrode so that the second electrode is covered, and forming a work function of the third electrode to be larger than a work function of the second electrode. The method of claim 10, Forming the second electrode and the third electrode, The second electrode is formed on the entire surface of the light emitting portion, And forming the third electrode on an outer edge portion of the second electrode, and forming a work function of the third electrode to be smaller than a work function of the second electrode. Preparing a substrate; Forming a third electrode on the substrate; Forming a second electrode on the third electrode; Forming a light emitting part on the second electrode; Forming a first electrode on the light emitting portion, One of the second electrode and the third electrode is formed on the outer edge portion, the work function of the second electrode and the third electrode is formed different from each other, The second electrode and the third electrode is a method of manufacturing an electroluminescent device, characterized in that the cathode electrode. The method of claim 13, Forming the second electrode and the third electrode, The third electrode is formed on the outer edge portion of the substrate, And forming the second electrode so that the third electrode is covered, and forming a work function of the second electrode to be greater than a work function of the third electrode. The method of claim 13, Forming the second electrode and the third electrode, Forming the third electrode on the front surface of the substrate; And forming the second electrode on an outer edge portion of the third electrode, and forming a work function of the second electrode to be smaller than a work function of the third electrode.

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