JP2000277267A - Organic el element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL element of simple configuration, which is manufacturable at a low cost and capable of luminous display of high quality with brightness. SOLUTION: This organic EL element is equipped with a transparent electrode 12, formed from a transparent material such as ITO or SnO2 on the surface of a transparent board 10 of glass, quartz, resin, etc., and a light emission layer 16 made of an organic EL material laminated on the transparent electrode 12. The light emission layer 16 is equipped with back face electrodes 14a-14d consisting of Al, Li, Cs, etc., arranged counterposed to the transparent electrode 12. The electrodes 14a-14d are grouped into a plurality of sets, each of which is furnished with an electrode connection part. An insulation base board 22 is installed confronting the back face electrodes 14a-14d, and an electricity conducting means such as a conductor pattern 24 or through-hole is provided for generating connection with the electrode connection part of each set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an organic EL device used for light emission display of a flat light source, a display, and other predetermined patterns.

[0002]

2. Description of the Related Art Conventionally, in an organic EL (electroluminescence) element, a transparent electrode is formed by forming a transparent ITO film on a transparent substrate on one surface and etching it into a predetermined stripe shape or the like. Further, a light emitting layer is formed on the surface of the transparent electrode. This light emitting layer is an organic EL material, such as α-NPD or triphenyldiamine derivative (T
It comprises a hole transporting material such as PD), an electron transporting material such as an aluminum quinolyl complex (Alq ₃ ) as a light emitting material, and various light emitting materials laminated thereon, or a mixed layer thereof. On the surface of the light-emitting layer, a stripe-shaped back electrode made of a metal such as Al, Li, Ag, Mg, or In is provided so as to face the transparent electrode in a direction orthogonal to the transparent electrode to form a light-emitting portion. are doing. In a light emitting portion, a so-called simple matrix type light emitting device in which a voltage is applied between a transparent electrode and a back electrode and light is emitted at intersections of stripes formed by these electrodes is generally used.

[0003] The driving method of such an organic EL element is as follows.
Since the resistance value of TO is higher than that of Al-Li, Al-Li
The back electrode side is used as a scanning electrode, and signals are output in parallel on the transparent electrode side of ITO.

[0004]

In the case of the above-mentioned prior art, in the case of this dot matrix display, it is necessary to increase the number of dots in order to perform a fine display or to increase the number of dots when the screen is enlarged. And the light emission time per line was shortened, resulting in a dark screen. Here, for example, assuming that the screen cycle is 1 / n second and the number of back electrodes to be scanned is m, the transparent electrodes are driven in parallel, so that the lighting time at the intersection with the back electrodes is 1 / n.
(M · n) seconds. Experimentally, human eyes can see the screen without flicker in less than 1/24 second.
According to the V standard, there are 30 screens per second. In this state,
If the number of electrodes to be scanned exceeds 128, the light emission time per light emitting element is short, resulting in dark images and poor quality.

On the other hand, if the number of scanning electrodes is increased in order to improve the image quality, the thickness of the electrodes becomes thinner if the screen area is constant, and the transparent electrode has a relatively high resistance value. There was also a problem that the value changed and brightness unevenness was generated on the screen.

Although the above problem can be solved by using a driving circuit using a TFT (thin film transistor), the TFT is expensive, and the price of a display device using an EL element becomes high. there were. Therefore,
The applicant of the present application has proposed a structure in which the electric resistance value on the transparent electrode side is reduced to be a driving electrode, and a driving method in which a screen is divided, in order to connect an external wiring to a wiring provided on the transparent electrode side. Since the structure and operation of the device are not easy and the organic EL light emitting material is chemically unstable, it is necessary to perform these operations in a dry atmosphere that is shielded from the outside air, and the processing steps are troublesome. Was.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide an organic EL device which can be manufactured at a low cost with a simple structure, and enables bright and high-quality light-emitting display. I do.

[0008]

The organic EL device of the SUMMARY OF THE INVENTION This invention includes a glass or quartz, transparent electrode formed of a transparent electrode material ₂ such as ITO or SnO on the surface of a transparent substrate such as a resin, the transparent electrode And a back electrode made of Al, Li, Cs, or the like, which is formed on the light emitting layer and is opposed to the transparent electrode. The back electrode is divided into a plurality of sets, an electrode connection portion is provided for each set of the back electrodes, an insulating substrate is provided facing the back electrode, and connected to an electrode connection portion for each set of the back electrodes. An organic EL element in which conductive means such as conductive patterns and through holes are provided on the insulating substrate, and the back electrode is connected to an external circuit via the insulating substrate.

The transparent electrode is formed in a number of stripes, and the back electrode is formed in a stripe in the direction orthogonal to the transparent electrode, and the back electrode is divided into a plurality of sets in the longitudinal direction of the stripe. Then, a predetermined number of the transparent electrodes are provided as a set. Then, a part of the set of the back electrodes is connected to the outside at an end of the transparent substrate,
Another set is an organic EL element connected to the conductive means such as a conductor pattern or a through hole formed on the insulating substrate.

[0010] The insulating substrate is provided with a conductive portion such as a through-hole which is electrically connected between the front and back surfaces.
A part of the set of the back electrodes is connected. The connection between the back electrode and the electrode connection portion of the insulating substrate is a connection member that is an anisotropic conductor or a conductive paint that exhibits conductivity in the thickness direction and exhibits insulation in the surface direction, or a member such as zebra rubber. It is done through.

Further, according to the present invention, the plurality of sets of back electrodes are connected to an external drive circuit for each of the plurality of sets, and the transparent electrodes are separately connected to the external drive circuit for each set of the back electrodes. An organic EL element which is connected and scans the transparent electrodes for each set with the transparent electrode side as a scanning electrode to apply a voltage to the light emitting layer.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show an embodiment of an organic EL device according to the present invention. The EL device according to this embodiment is provided on one surface of a transparent substrate 10 made of glass, quartz, resin, or the like. ₂ through a transparent insulator layer such as a transparent electrode 12 at a predetermined pitch.
Is provided. The transparent electrode 12 is made of ITO or SnO ₂
Etc., formed to a thickness of 1000 to 2000 mm,
In FIG. 1, a transparent electrode 12 extends in a direction perpendicular to the plane of the drawing, extends to a side edge of the substrate 10, and is connected to an external drive circuit.

A light emitting layer 16 is laminated on the transparent electrode 12 and the surface of the transparent insulator layer exposed therebetween through a buffer layer (not shown) such as copper phthalocyanine (CuPc) provided as necessary. The light emitting layer 16 is 500
It is composed of a hole transporting material having a thickness of about Å and an electron transporting material having a thickness of about 500Å. The hole transport material is laminated on the entire surface of the transparent electrode 12 and the transparent insulator layer exposed therebetween.

Here, the light emitting layer 16 is made of α-NPD, a triphenyldiamine derivative (T
PD), hydrazone derivatives, arylamine derivatives and the like. Further, as a red light emitting material of the electron transport material, DC is used.
M, an organic EL light emitting material such as a distyrylbiphenyl derivative (DPVBi) is used as the blue light emitting material, and an aluminum quinolyl complex (Alq3) is used as the green light emitting material. Further, an appropriate light emitting material may be mixed.

As shown in FIG. 2, the electron transporting material of the light emitting layer 16 is formed in a stripe shape in a direction perpendicular to the transparent electrodes 12 and is divided into four sets so as to divide the number of the transparent electrodes 12 into four. The divided back electrodes 14a, 14b, 14c,
14d are stacked. Back electrodes 14a, 14b, 1
4c and 14d face the glass or ceramics or other insulating insulating substrate 22 and equidistant electrode connecting portions facing the back electrodes 14a, 14b, 14c and 14d on the surface of the insulating substrate 22 on the transparent substrate 10 side. Conductor pattern 24
Is provided. The conductor pattern 24 includes two sets of patterns each having the same number as the number of stripes of the back electrode, are provided so as to be electrically connectable to the back electrodes 14b and 14c, respectively, and extend to both side edges of the insulating substrate 22. Insulating substrate 22
The flexible pattern 26 is connected to the end of the conductor pattern 24 for each conductor pattern.

The connection between the back electrodes 14b and 14c and each conductor pattern 24 is made of, for example, a known anisotropic conductor having conductivity in the thickness direction and insulating in the plane direction, or a conductor pattern in the thickness direction. A connection member 28 such as zebra rubber having conductor portions formed at the same pitch as 24 can be used. In addition, portions other than the portion in contact with the connecting member 28 are covered with an insulating material (not shown) such as SiO ₂ .

The set of the back electrodes 14a, 14d on the side edge portion side of the transparent substrate 10 is connected to the back electrodes 14a, 14d, respectively.
Extend to both side edges of the transparent substrate 10, and each side edge is connected to a flexible wiring pattern 20 connected to an external drive circuit. The peripheral portions of the transparent substrate 10 and the insulating substrate 22 are hermetically sealed by an airtight sealing resin 30.
Here, the back electrodes 14a, 14b, 14c, 14d
It is composed of a metal thin film containing Al, Li, Ag, Mg, In, Cs and the like. The conductor pattern 24 is formed by etching a copper foil or the like in a stripe shape.

In the method of manufacturing an organic EL device according to this embodiment, a transparent insulating layer is formed on a smooth transparent substrate 10 if necessary, and then a transparent electrode material such as ITO is vacuum-thinned. Provided by At this time, the transparent electrode 12
Is deposited by using a wire mask or the like so that a plurality of layers are formed with a width of 300 μm and an interval of about 20 μm.

Next, a buffer layer having a thickness of 500 to 1000 ° is deposited on the entire surface of the stripe-shaped transparent electrode 12 as necessary, and then a hole transporting material is deposited on the transparent electrode 12 in a thickness of 250 to 1000 °.
The light emitting layer 16 is formed by vapor deposition to a thickness of 500 ° and further vapor depositing an electron transport material in the same manner.

Thereafter, the back electrodes 14a, 14b, 14
c, 14d are deposited. For the deposition of the back electrode 14, a mask deposition method is used as in the case of the transparent electrode. At this time, the striped pattern is separated for each of the back electrodes 14a, 14b, 14c, and 14d, and the pair of back electrodes 14a, 14d on both side edges of the transparent substrate 10 is
To the side edge of. Thereafter, an insulating member is vapor-deposited by mask vapor deposition so as to leave the electric connection portion of the connection member 28.

Thereafter, the transparent substrate 10 is transferred to a dry nitrogen atmosphere, a connection member 28 is attached to the back electrodes 14b and 14c, and a sealing resin 30 is provided on the entire periphery to form a transparent resin. Then, a desiccant such as BaO is added to cover the insulating substrate 22 to seal the periphery.

The driving method of the EL element of this embodiment is as follows.
Back electrodes 14a, 14b, 14c, 14d divided into sets
Are scanned at the transparent electrode 12 side for each set, and one screen is scanned at four locations, one quarter at a time. The light emission time along one line of each transparent electrode 12 is four times smaller than the conventional one. Double the time. Further, in this embodiment, since the back electrode 14 also extends the wiring from the insulating substrate 22 side via the conductor pattern 24, the insulating substrate 24 is on the rear side of the display screen. However, wiring processing can be easily performed.

Since the scanning is performed on the surface electrode 12 side, the resistance value on the surface electrode 12 side becomes a problem. However, by forming a thin conductive pattern of Al or the like along the side of the surface electrode 12, the resistance is reduced. The value can be greatly reduced. This conductor pattern may be formed between each light emitting pixel, and does not affect the screen display.

Next, a second embodiment of the present invention will be described with reference to FIG.
The description will be made based on FIG. Here, the same members as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the organic EL element of this embodiment, the back electrode is formed in a stripe shape in a direction orthogonal to the transparent electrode 12, and the longitudinal direction is divided into six so as to divide the number of the transparent electrodes 12 into six. . Back electrodes 34a, 3a formed on the surface of light emitting layer 16
4b, 34c, 34d, 34e, and 34f are formed in stripes in the same direction, and are insulated at each divided portion.

The EL element of this embodiment has a back electrode 34a on the side edge of the transparent substrate 10 similar to the above embodiment.
34f extends to the side edge of the transparent substrate 10 and is connected to the flexible pattern 20. Further, the inner back electrodes 34b and 34e are connected to the conductor pattern 24 of the insulating substrate 22 and to the external flexible pattern 26 in the same manner as in the above embodiment.

Then, the back electrodes 34c,
34d is a through hole 3 for each back electrode pattern.
6, is led out to the front side of the insulating substrate 22.
The through hole 36 is electrically connected to the outer surface of the insulating substrate 22 independently for each pattern of the back electrodes 34c and 34d. On the front side of the insulating substrate 22, each through hole 36
Is connected to an external drive circuit by a flexible pattern or the like from an electrode (not shown).

The driving method of the EL element of this embodiment is similar to that of the above-described embodiment, and the back electrodes 34a, 34 divided into six parts are provided.
The transparent electrodes b, 34c, 34d, 34e, and 34f are scanned on the transparent electrode 12 side for each of the divided groups, and six locations are scanned on one screen to enable bright display.

Next, a third embodiment of the present invention will be described with reference to FIG.
The description will be made based on FIG. Here, the same members as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the organic EL element of this embodiment, for example, in a wiring pattern 24 thinned for color display, a pad 4 of a connection portion connecting the conductor pattern 24 on the insulating substrate 22 side and the back electrode is provided.
It is designed to take 0 larger. Therefore, by arranging the pads 40 so as to be shifted from each other by ピ ッ チ pitch and laying the conductor pattern 24 so as to avoid the pads 40, the pads 40 can be made large. This makes it possible to easily form, for example, a color display in which light emitting dots of the three primary colors R, G, and B are used as one pixel with high luminance.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
The description will be made based on FIG. Here, the same members as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the organic EL device of this embodiment, the back electrodes 44a, 44b, 44c, and 44d formed on the surface of the light emitting layer 16 are formed in a stripe shape in a direction orthogonal to the transparent electrode 12, and the number of the transparent electrodes 12 is reduced. The longitudinal direction of the stripe is divided into four so as to divide it into four equal parts.

The EL element of this embodiment has a structure in which each back electrode 4
4a, 44b, 44c, and 44d all correspond to the insulating substrate 22.
Back electrode 4 formed on the surface of each back electrode light emitting layer 16
It is led out to the front side of the insulating substrate 22 through through holes 46 corresponding to the stripe patterns 4a, 44b, 44c and 44d. The back electrode 44a,
The connection between 44b, 44c, 44d and through hole 46 is performed by applying an anisotropic conductor 48 having conductivity in the thickness direction and insulating property in the surface direction as a connection member on one surface. The back electrodes 44a, 44b, 44 are formed by an anisotropic conductor 48 having conductivity in the thickness direction and insulation in the plane direction.
Each of the stripes 44c and 44d is independently connected to the through hole 46. The drive I is provided outside the insulating substrate 22.
C may be provided directly, or may be connected to an external circuit using flexible wiring.

It should be noted that an organic conductor material can be used in place of the anisotropic conductor 48. In this case, the back electrodes 44a, 44b, 44c, and 44d are covered with an insulating layer except for the connection portions. Then, an organic conductor material is applied to the entire surface and evacuated to connect the through holes. In this case, in the thickness direction, the distance between the through hole and the cross-sectional area for conduction is short, so that the conductive pattern shows conductivity.Between adjacent patterns, the distance is long and the cross-sectional area for conduction is small. Almost negligible.

The driving method of the EL element of this embodiment is the same as that of the above-described embodiment.
The scanning is performed on the side, and four places are scanned on one screen to enable bright display.

The organic EL device of the present invention is not limited to the above embodiment, and the type of the insulating substrate provided on the back side of the transparent substrate can be appropriately selected. Means for electrically connecting the back electrode and the insulating substrate can be appropriately selected. As a means for reducing the electric resistance on the transparent electrode side, a conductor pattern for the transparent electrode may be formed on the back electrode side in addition to the conductor pattern on the transparent substrate surface, and an appropriate method may be employed.

[0034]

According to the organic EL device of the present invention, an insulating substrate is provided on the back side of a transparent substrate, the back electrode is divided, and scanning can be performed for each divided group. Can be performed for each divided group, and a bright screen can be provided with a simple structure. Further, by providing the insulating substrate on the back side of the transparent substrate and providing the conductor pattern connected to the back electrode, the electrical connection of the divided back electrodes is facilitated, and the connection of the peripheral circuit is also facilitated.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an organic EL device according to a first embodiment of the present invention.

FIG. 2 is a partial plan view showing a connection portion between a back electrode and a conductor pattern of the organic EL element according to the first embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing an organic EL device according to a second embodiment of the present invention.

FIG. 4 is a partial plan view showing a back electrode and a connection portion of an organic EL device according to a third embodiment of the present invention.

FIG. 5 is a partial plan view showing a back electrode and a connection portion of an organic EL device according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Transparent substrate 12 Transparent electrode 14a, 14b, 14c, 14d Back electrode 16 Light emitting layer 20, 26 Flexible pattern 22 Insulating substrate 24 Conductive pattern 28 Connection member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshio Sato 3158 Shimo-Okubo, Osawano-cho, Kamishinkawa-gun, Toyama Prefecture Hokuriku Electric Industry Co., Ltd. (72) Inventor Hiroyoshi Onagawa 77-2 Arisawa, Toyama-shi, Toyama F-term (reference) 3K007 AB02 AB04 AB18 BA06 BB01 CA01 CB01 CC05 DA01 DB03 EB00 FA02 5C094 AA08 AA10 AA44 AA45 BA27 CA19 CA24 DA13 DB01 DB02 DB04 DB05 EA04 EA05 EB02 EC01 EC02 ED03 FA01 FA02 FB01 FB12

Claims (5)

[Claims] 1. A transparent electrode formed of a transparent electrode material on a surface of a transparent substrate, a light emitting layer made of an organic EL material laminated on the transparent electrode, and a light emitting layer laminated on the light emitting layer.
In an organic EL device having a back electrode formed so as to face the transparent electrode, the back electrode is divided into a plurality of sets, and an electrode connection portion is provided for each set of the back electrodes. An insulating substrate is provided to face, conductive means for connecting to the electrode connection part of each set of the back electrode is provided on the insulating substrate, and the back electrode is connected to an external circuit via the insulating substrate. Organic EL element. 2. The transparent electrode is formed in a stripe shape, the back electrode is formed in a stripe shape in a direction orthogonal to the transparent electrode, and the back electrode is divided into a plurality of sets in a longitudinal direction of the stripe. A set of the predetermined number of the transparent electrodes, a part of the set of the back electrodes is connected to the outside at an end of the transparent substrate, and the other set is connected to the conductive means formed on the insulating substrate. The organic EL device according to claim 1, wherein: 3. The insulating substrate according to claim 1, wherein a conductive portion is provided between the front and back surfaces of the insulating substrate, and a part of the set of back electrodes is connected to the conductive portion. Organic EL device. 4. The connection between the back electrode and the electrode connection portion of the insulating substrate is made via a connection member having conductivity in the thickness direction and insulation in the plane direction. 4. The organic EL device according to claim 2, 2 or 3. 5. The plurality of sets of back electrodes are connected to an external drive circuit for each of the plurality of sets, and the transparent electrodes are separately connected to the external drive circuit for each set of the back electrodes. 5. The organic EL device according to claim 2, wherein the transparent electrode side is used as a scanning electrode, and the transparent electrode is scanned for each set to apply a voltage to the light emitting layer.