JPH10321371A - Novel organic electroluminescent element, manufacture thereof and application thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescence element which has high light emitting efficiency and is excellent in durability and emits a beam of light excellent in directivity by including a light emitting discotic liquid crystal as an organic light emitting layer between an anode and a cathode formed in layers on a substrate. SOLUTION: A transparent anode 7 such as an ITO is formed on a glass substrate 1, and an electron hole transport layer 8 and a polyimide film 9 are arranged when necessary, and a light emitting discotic liquid crystal layer 10 is formed on it. This light emitting discotic liquid crystal is composed of a discotic liquid crystal having light emitting capacity and/or a discotic liquid crystal containing a light emitting material, and is formed by polymerizing a polymerized low molecular weight discotic liquid crystal, and a material composed of a high polymer whose optical axis is almost vertically oriented to the anode 7 and a cathode 11 formed on it, is desirable. Therefore, an organic EL element to emit a beam 16 of light excellent in directivity by applying voltage on the anode 7 and the cathode 11, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel organic electroluminescent device (hereinafter abbreviated as "organic EL device") having high luminous efficiency and excellent directivity of light emission, a method for producing the same, and applications thereof. The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art Among liquid crystal display devices, liquid crystal display devices are rapidly expanding their application fields, but have disadvantages such as lack of sharpness of an image because they do not emit light by themselves. Therefore, Tang proposed an organic EL device having a light emitting layer and a hole transport layer between a hole injection electrode and an electron injection electrode.
The luminous efficiency of this device has been greatly improved as compared with the conventional method, and research for practical use is progressing. FIG. 3 shows a configuration of a typical organic EL element.

An anode 2 used as a hole injection electrode, for example, a glass substrate 1 provided with an indium-doped tin transparent electrode
Next, as the hole transport layer 3, for example, N, N'-diphenyl-N, N '
-Di (3-methylphenyl) -1,1'-biphenyl-4,4'-diamine (hereinafter abbreviated as "TPD") is formed by vapor deposition to form a thin film having a thickness of about 500 angstroms. As the light emitting layer 4, for example, tris (8-quinolinolato) aluminum (hereinafter abbreviated as "Alq") is formed by vapor deposition to a thickness of about 500 angstroms, and a cathode 5 used as an electron injection electrode, for example, a silver-doped magnesium electrode is formed. And
When a negative voltage of 5-10 V is applied to the anode, green light emission is obtained.

There has been proposed a method in which an organic EL element is disposed on the back of a liquid crystal display element and used for illuminating the liquid crystal display element of a liquid crystal display device. Not converted.

[0005]

Various improvements have been made to the basic structure of the organic EL device proposed by Tang.

For example, a method of providing an electron transport layer such as phenylbiphenyloxadiazole (hereinafter abbreviated as “PBD”) between a light emitting layer and a cathode (C. Adachi,
S. Tokito, T. Tsutsui, S. Saito., Jpn. J. Appl. P
hy., Vol. 27, L269 (1988)), a method in which a lithium-doped aluminum electrode is used instead of a silver-doped magnesium electrode as a cathode, or a method in which three colors of RGB are emitted to obtain white light (Japanese Patent Laid-Open No. 7-90260). Gazette.) Has been proposed.

Further, a method of obtaining polarized light emission by orienting an electroluminescent layer exhibiting smectic liquid crystallinity in one direction (JH We
ndorff et al, Liquid Crystal, Vol. 21, NO. 6, 903 (1
996)).

However, even with these proposals, the luminous efficiency is still insufficient, and when a high current is applied to obtain a practical luminous intensity, a considerable part of the power applied to the element is consumed as heat. Therefore, the durability of the device is reduced due to the heat generated by the device.

On the other hand, there has been proposed a method of arranging the element on the back surface of the liquid crystal display element and using the element for illumination of the liquid crystal display element of a liquid crystal display device. It has not been put to practical use due to its nature. For illumination of a liquid crystal display element, a light source having high directivity is required in two application fields. One area is to increase the directivity in the direction perpendicular to the display surface of the liquid crystal display element to secure the brightness of the front, which is mainly used for small personal applications such as portable liquid crystal display elements. is there. The other is to pass a light beam with a high directivity in the right angle from the back of the liquid crystal display element through the liquid crystal display element, and then spread the light ray to a wide angle by optical components installed on the observer side, This is an area for resolving a narrow viewing angle, which is one of the drawbacks of display devices, and is particularly required for large devices such as display devices of desktop computers.

In order to solve such a problem, the present invention provides an organic EL element having high luminous efficiency, excellent durability, and excellent directivity of the obtained light beam, and an element for lighting the display element. It is an object of the present invention to provide a liquid crystal display device having excellent directivity in a direction perpendicular to the display surface or a wide viewing angle when applied to a liquid crystal display device.

[0011]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, have obtained by using a luminescent discotic liquid crystal layer as a luminescent layer of an organic EL device. The directivity of the light beam to be obtained is improved, the luminous efficiency is increased, and as a result, the durability can be increased, and the present invention has been completed.

Further, by using this element, it is possible to provide a liquid crystal display device having excellent directivity in the direction perpendicular to the display surface or a wide viewing angle.

That is, the present invention relates to an organic EL device,
An organic EL device comprising a light emitting discotic liquid crystal layer as a light emitting layer between an anode and a cathode, a method for producing the same, and application to a liquid crystal display device.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A disco check liquid crystal is a liquid crystal phase developed by molecules having a highly planar disk-shaped skeleton discovered by Chandra Seca, and its optical characteristic is its refractive index. It has negative optical uniaxiality. A liquid crystal having this property is referred to as "disco check liquid crystal" in this specification.

[0015] In the present specification, the term "luminescent discotic liquid crystal" refers to a discotic liquid crystal having a luminous ability; and / or a discotic liquid crystal containing a luminescent material. Tic liquid crystals include those having luminous ability by themselves, those having no luminous ability by themselves, and mixtures of both. As discotic liquid crystals that can be used in the present invention, any conventionally known discotic liquid crystals can be used (for example, JP-A-8-50204 and JP-A-8-3204).
See 34621 publication. ), For example, compounds I to VI.

[0016]

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[0017]

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[0018]

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[0019]

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[0020]

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[0021]

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In the compounds I to VI, R represents the following groups. Although all compounds having the following groups are not discotic liquid crystals, an appropriate group that becomes a discotic liquid crystal can be selected and used based on a known technique or the like. R ¹ —, R ¹ —O—, R ¹ —CO—O— or R ¹ —O—CO—.

R ¹ is an alkyl group, in which a ring such as a phenylene group or a cyclohexylene group is combined,
There are those in which an oxygen atom is arranged between carbon and carbon.

For example, specifically, R ² —, R ² —O—,
R ² —O—R ³ —, R ² —O—R ³ —O—, R ² —O-Ph
^{-COO-, R 2 -O-Ph-} CH = CH-COO-,
_{CH 2 = CH-COO-R} 3 -O-Ph-COO-. (R
² - represents an alkyl group, -R ³ - are alkylene radicals, -Ph- is a phenylene group) M represents copper, iron, cobalt, nickel, a metal or two protons of zinc.

Further, discotic liquid crystals to be developed in the future can be adopted as the discotic liquid crystal of the present invention as long as they have the above-mentioned characteristics.

As described above, the luminescent discotic liquid crystal layer used in the present invention may be composed of only a discocheck liquid crystal having a luminous ability, or may be a discotic liquid crystal containing a luminescent material. Here, the discotic liquid crystal in the discotic liquid crystal containing a luminescent material may be any of those having luminous ability by themselves, those having no luminous ability by themselves, and mixtures of both. The EL light emitting material can be selected from known fluorescent materials,
A compound to be found in the future may be used. In this case, any organic compound having fluorescence may be used. Examples of known luminescent materials include Alq, coumarin, distyrylarylene (hereinafter, “DTV”).
Bi ”. ), Beryllium benzoquinoliol complex (hereinafter abbreviated as “Bebq”), porphyrin derivatives, and the like.

Further, when a luminescent material is contained, it is preferable that the luminescent material has a planar structure as much as possible so as not to hinder the alignment of the discotic liquid crystal layer. Especially,
When the luminescent center has a metal ion, it preferably has tetradentate coordination ability. From these points, porphyrin derivatives are preferred.

In the configuration of the known organic EL device shown in FIG. 3, since the light ray 16 emitted from the light emitting layer has no directivity, if the refractive index of the light emitting layer is n1, the external quantum efficiency ηex
According to the following literature, it is shown that ηex = １ ／ · (n1) ² : Neil C. Grenham, Richard H. Fr
iend and Donal DC Bradley, Adv. Mater. 1994, 6,
NO.6, 491.

When n1 is 1.6, ηex is 0.2.

As shown in FIG. 2, if an ideal light emitting layer 6 is used in which the light beam 16 is emitted only in a direction completely perpendicular to the substrate (the effect of the interface reflection is ignored if the effect of interface reflection is ignored). Luminous efficiency 100 / ηex times as compared with the case of FIG. 3 is obtained (because it is 100%). The present invention achieves the ideal state as shown in FIG. 2 by using a luminescent discotic liquid crystal layer instead of a conventionally known luminescent layer.

In the present invention, it is preferable that the optical axis of the luminescent discotic liquid crystal is substantially perpendicular to the anode and the cathode, and the substantially perpendicular is within a range of ± 10 degrees with respect to the perpendicular.

In order to make such an angle, it is preferable to align the liquid crystal so as to have such an angle. When aligning the luminescent discotic liquid crystal, the alignment means can be selected from known means. For example, the alignment may be performed by a magnetic field, or the luminescent discotic liquid crystal layer may be rubbed in one direction.

A luminescent discotic liquid crystal is applied on the rubbed alignment film to align the liquid crystal layer (Japanese Patent Laid-Open No.
See JP-A-8-50204. ) You can.

Further, when a hole transport layer described later is used, the hole transport layer can be rubbed and aligned, and a luminescent discotic liquid crystal can be applied thereto to align the liquid crystal layer. If the thickness of the luminescent discotic liquid crystal layer is too large, a distribution of the inclination of the liquid crystal layer may occur in the thickness direction, and therefore it is preferably 2000 Å or less. on the other hand,
From the viewpoint of manufacturing safety, the thickness is preferably 200 Å or more.

The alignment film is made of a known liquid crystal alignment material (for example,
See JP-A-8-50204. ) Can be used, but especially
Polyimide is excellent in durability.

The phase of the discotic liquid crystal is C. Destrade
Cryst. 106, 121 (1984), ND phase (discotic nematic), Dho phase (hexag).
onordered columnar phas
e), Dhd phase (hexagonal disorder)
red column phase, Drd phase (rectangular disordered c)
oluminar phase, Dob phase (obliq)
ue columnar phase). Among them, a discotic nematic phase (ND phase) is preferable from the viewpoint of easy orientation.

The light-emitting discotic liquid crystal layer of the present invention may show a light-emitting discotic liquid crystal phase in the final device, and may be any as long as it shows a light-emitting discotic liquid crystal phase at the stage of alignment formation. From the viewpoint of durability, the discotic liquid crystal layer is preferably mainly made of a polymer.

When the luminescent discotic liquid crystal layer of the present invention is used for the luminescent layer, light is emitted almost perpendicularly from the element surface, so that the luminous efficiency can be increased. Is possible, resulting in increased durability

Further, as described above, since the organic EL device of the present invention acts as a light source having a large front directivity, the directivity in the direction perpendicular to the display surface of the liquid crystal display device is increased to increase the brightness of the front. It can be suitably used for small personal uses such as a secured portable liquid crystal display element. In addition, after transmitting a light beam having a large directivity in a right angle direction from the back of the liquid crystal display device through the liquid crystal display device, the light beam is spread at a wide angle by an optical component provided on the observer side, which is a disadvantage of the liquid crystal display device. It is also possible to eliminate the narrow viewing angle, which is one of them, and it can be expected to be used for a large device such as a display device of a desktop computer. As this optical component, means for spreading various light rays at a wide angle can be employed (for example, Japanese Patent Application No. 8-101608, in which one of the present inventors is included as an inventor; see Example 7 below). ], And International Publication WO95 / 0
See No. 1584. ) And those developed in the future can be adopted.

In the present invention, in addition to the layer containing the luminescent discotic liquid crystal, a hole transport layer is provided between the layer and the anode, and / or
Alternatively, an electron transport layer can be used between the cathode and the cathode.
It is preferable because the barrier for injecting carriers from a voltage can be reduced and carriers can be injected at a low voltage, and the penetration of carriers of the opposite polarity can be blocked and the recombination probability can be increased.

In this case, a conventionally known hole transporting layer (for example, see JP-A-1-243393) or an electron-transporting layer (for example, see JP-A-2-16791) can be employed. Polyvinylcarbazole (PV
Cz) and amine derivatives are preferred. As the electron transport layer, an oxadiazole derivative or the like is preferable.

[0042]

The luminescent discotic liquid crystal layer is formed by an organic EL.
By using it for the light emitting layer of the device, it is possible to increase the luminous efficiency and durability, and when using it as a liquid crystal display device, raise the directivity in the direction perpendicular to the display surface and secure the brightness in the front. On the other hand, it is also possible to widen the viewing angle of the liquid crystal display element by means of spreading the light ray to a wide angle after passing the light ray having a high directivity in the right angle direction from the back of the liquid crystal display element through the liquid crystal display element.

[0043]

EXAMPLES Next, the organic EL device of the present invention will be specifically described with reference to examples.

Example 1 As shown in FIG.
As a hole transport layer 8, polyvinyl carbazole (PVC)
The methylene chloride solution of z) was spin-coated to a thickness of 500 Å. Further, a polyimide 9 was spin-coated thereon at a thickness of 250 angstroms,
After the heat treatment, a rubbing treatment was performed. Hexahexyloxytriphenylene (Compound I; R: nC ₆ H ₁₃ O
-) 45%, hexaoctyloxytriphenylene (compound I; R: nC ₈ H ₁₇ O-) 45% and zinc-porphyrin liquid crystal (compound VI; R: nC ₈ H ₁₇ O-, M: Z)
n) spin-coating a chloroform solution of a 10% luminescent discotic liquid crystal composition on a polyimide film,
A luminescent discotic liquid crystal layer 10 having a thickness of 500 Å was obtained. After heating this to 120 ° C., it was allowed to cool to room temperature. This liquid crystal layer showed an ND phase. Further, silver-doped magnesium was vapor-deposited thereon to form a cathode 11, thereby obtaining an organic EL device.

On the other hand, the above-mentioned hexahexyloxytriphenylene 45% and hexaoctyloxytriphenylene 45%
In place of the luminescent discotic liquid crystal composition comprising 10% of zinc-porphyrin liquid crystal and zinc-porphyrin liquid crystal, the above-mentioned zinc-porphyrin liquid crystal dispersed in 10% of polymethyl methacrylate was used to prepare a light-emitting layer. The performance was compared with the fabricated device (Comparative Example).

When the devices of Example 1 and Comparative Example were driven at a direct current of 10 V, red light emission was observed. The angle dependence of the emission intensity of the device of Example 1 was higher than that of the device of Comparative Example. The intensity was 4.0 times, the light beam 16 was emitted almost perpendicularly from the element surface, and the half value width indicating the angle dependence of light emission was a very small value of 20 degrees.

Example 2 In the method of Example 1, a hole transport layer of PVCz in methylene chloride was spin-coated to a thickness of 500 angstroms, and then hexapropenoyloxybutyrenoxyphenyl was coated on PVCz. Carbonyloxytriphenylene (Compound I; R: CH ₂ =
_{CH-CO 2 -C 4 H 8} -O-Ph-CO 2 -) 45%, hexa-hexyloxy triphenylene (Compound I; R: n-
_{C 6 H 13 O-) 45%} , DTVBi9%, and a photopolymerization initiator material Irgacure 907; chloroform solution of 1% luminous Deisuko tic liquid crystal composition consisting of spin coating, thickness 500
An Angstrom luminescent discotic liquid crystal layer was obtained. This layer showed an ND phase at 120 ° C.

While heating this at 120 ° C., it was irradiated with ultraviolet light using a high-pressure mercury lamp for one minute, allowed to cool to room temperature, and rubbed in one direction with gauze. Further, silver-doped magnesium was deposited thereon to obtain an organic EL device.

On the other hand, DTVBi9 was added to polymethyl methacrylate.
%, A light-emitting layer was prepared, and the performance was compared using a device manufactured in the same manner as described above as a comparative example.

When the devices of the present example and the comparative example were driven at 10 V DC, blue light emission was observed, but the emission intensity of the device of the present example was higher than that of the comparative example. Also, the integrated intensity was 4.0 times, light was emitted almost perpendicularly from the element surface, and the half value width indicating the angle dependence of light emission was a very small value of 20 degrees. The device of the comparative example emitted light having a very wide half value width of 125 degrees.

Example 3 An organic EL device was fabricated in the same manner as in Example 1, except that Bebq was used instead of the zinc-porphyrin liquid crystal.

On the other hand, Bebq was added to polymethyl methacrylate.
The light-emitting layer was prepared in the same manner by dispersing it by 10%, and the performances of the devices manufactured in the same manner as described above were compared as comparative examples.

When the device of this example and the device of the comparative example were driven at a direct current of 10 V, green light emission was observed.
Regarding the angle dependence of the emission intensity, the device of the present example has an integrated intensity of 4.0 times that of the device of the comparative example, light is emitted almost perpendicularly from the device surface, and the half-value width indicating the angle dependence of emission. Was a very small value of 20 degrees.

Example 4 A methylene chloride solution of PVCz as a hole transport layer was spin-coated on a glass substrate with ITO (thickness: 1 mm) to a thickness of 500 angstroms. Further, a polyimide film was spin-coated thereon to a thickness of 250 angstroms, heated at 200 ° C., and then rubbed.

Hexapropenoyloxybutyrenoxyphenylcarbonyloxytriphenylene (compound I; R: CH ₂ ＣＨCH—CO ₂ —C ₄ H ₈ —O—Ph—CO
₂ -) 45%, hexa-hexyloxy triphenylene (Compound _{I; R: n-C 6} H 13 O-) 45%, coumarin 9%, and a photopolymerization initiator material Irgacure 907; luminescent Deisuko tic liquid crystal composition consisting of 1% The solution was spin-coated with a chloroform solution to obtain a luminescent discotic liquid crystal layer having a thickness of 500 Å. This layer showed an ND phase at 120 ° C.

While heating this at 120 ° C., it was irradiated with ultraviolet light using a high-pressure mercury lamp for one minute and allowed to cool to room temperature.
Further, lithium-doped aluminum was deposited thereon to obtain an organic EL device.

On the other hand, a light emitting layer was prepared in the same manner as above by dispersing 9% of coumarin in polymethyl methacrylate, and a device manufactured in the same manner as described above was used as a comparative example to compare the performance with the device of this example.

When the devices of the present example and the comparative example were driven at 10 V DC, blue-green light emission was observed in both devices. The angle dependence of the light emission intensity of the device of the present example was higher than that of the device of the comparative example. Light is emitted almost perpendicularly from the element surface, and the half-value width indicating the angle dependence of light emission is 25 times.
The degree was very small.

Example 5 In the device preparation of Example 1, after coating with PVCz, the PVCz layer was rubbed in one direction with gauze. Hexapropenoyloxybutyrenoxyphenylcarbonyloxytriphenylene (Compound I; R: CH
_{2 = CH-CO 2 -C 4} H 8 -O-Ph-CO 2 -) 45%,
Hexahexyloxytriphenylene (Compound I; R:
_{n-C 6 H 13 O-)} 45%, DTVBi9%, and a photopolymerization initiator material Irgacure 907; chloroform solution of 1% luminous Deisuko tic liquid crystal composition consisting of spin coating, the thickness
A luminescent discotic liquid crystal layer of 500 Å was obtained. This layer showed the ND phase.

While heating this at 120 ° C., it was irradiated with ultraviolet light using a high-pressure mercury lamp for one minute and allowed to cool to room temperature.
Further, silver-doped magnesium is deposited thereon to form organic E
An L element was obtained.

On the other hand, DTVBi9 was added to polymethyl methacrylate.
%, A light-emitting layer was prepared, and the device manufactured in the same manner as described above was used as a comparative example.

When the devices of this embodiment and the comparative example were driven at 10 V DC, blue light emission was observed in both devices. However, the angle dependence of the luminescence intensity was more integrated in the present embodiment than in the device of the comparative example. The intensity was 3.8 times, light was emitted almost perpendicularly from the element surface, and the half-value width indicating the angle dependence of light emission was a very small value of 24 degrees. The half width is 125 from the device of the comparative example.
Very wide light was emitted.

[Example 6] In the device preparation of Example 5, hexahexyloxytriphenylene (compound I; R: nC ₆ H ₁₃ O-) 45 was added to the rubbed PVCz layer.
%, Hexaoctyloxytriphenylene (Compound I;
R: nC ₈ H ₁₇ O-) 45% and zinc-porphyrin liquid crystal (compound VI; R: none, M: Zn) 10% chloroform solution of a luminescent discotic liquid crystal composition was spin-coated, A luminescent discotic liquid crystal layer having a thickness of 500 angstroms was obtained. After heating this to 120 ° C., it was allowed to cool to room temperature. This layer showed the ND phase. Furthermore,
Silver-doped magnesium was evaporated thereon to obtain an organic EL device.

On the other hand, as a comparative example, an element was prepared in the same manner as described above except that 10% of a zinc-porphyrin liquid crystal (compound VI; R: none, M: Zn) was dispersed in polymethyl methacrylate to form a light emitting layer. Their performance was compared.

When the devices of the present example and the comparative example were driven at 10 V DC, red light emission was observed, and the angle dependence of the light emission intensity was higher in the device of the present example than in the device of the comparative example. Also, the integrated intensity was 3.8 times, light was emitted almost perpendicularly from the element surface, and the half value width indicating the angle dependence of light emission was a very small value of 24 degrees. The device of the comparative example emitted light having a very wide half value width of 125 degrees.

[Embodiment 7] An example of use as a liquid crystal display element in a liquid crystal display device will be described with reference to FIG.

The liquid crystal cell 14 is a TFT driven TN.
TFT drive T which is liquid crystal and has VGA-compatible pixels
N liquid crystal display cells were used. As the polarizing plate 13A on the incident side, a normal light absorbing organic polarizing plate was used. The organic EL element 15 prepared in Example 1 was disposed on the side of the polarizing plate opposite to the liquid crystal cell on the incident side.

Similarly, a light absorption type organic polarizing plate was used for the polarizing plate 13B on the emission side. The direction of the polarization axis is appropriately selected depending on the display mode (normally white or normally black). In the present embodiment, normally white display is performed, and the polarization axis of the polarization plate 13A on the incident side surface has a 90-degree polarization axis. The polarization axis of the polarizing plate 13B on the emission side was set in the rotated direction.

A beam expanding means is provided in contact with the polarizing plate 13B on the emission side. The beam expanding means has the structure shown in FIG. An example of the manufacturing method is shown below. Visible light curable acrylic monomer is cast on a flat mold to form a square trapezoidal array, a polyethylene terephthalate film is placed on top of it, and visible light curing is performed by irradiating visible light from above the polyethylene terephthalate film. Acrylic monomer was polymerized. After applying a water-soluble polymer as a mask to the top surface of the square trapezoidal array 12C formed on the base material 12T thus obtained, the reflection film 12 is formed.
Aluminum as R is deposited, and black paint 12
After the application of X, the aluminum and the black paint were removed by immersion in warm water together with the water-soluble polymer.

The dimensions of the rectangular trapezoid of the light beam enlarging means formed in this manner are such that the bottom surface is 200 μm square and the top surface is 1 μm.
It is 00 microns square and 200 microns high.

The thus manufactured liquid crystal display device had high luminance and high contrast of 15 or more over a wide viewing angle of 110 degrees.

[0072]

According to the present invention, the organic EL device contains a light-emitting discotic liquid crystal layer as a light-emitting layer, whereby the light-emitting efficiency is increased and the durability is improved as compared with the conventional method. When used for illuminating a display element of a liquid crystal display device, it is possible to provide a liquid crystal display device having excellent directivity and a wide viewing angle.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an element obtained in Example 1 of the present invention.

FIG. 2 is a schematic diagram showing an organic EL element and light emission when an ideal light emitting layer that solves the problem of the present invention is used.

FIG. 3 is a schematic view of a typical organic EL device as a conventional method.

FIG. 4 is a schematic diagram of a liquid crystal display device using the device of the present invention as a liquid crystal display device.

FIG. 5 is an enlarged view of a light beam expanding means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole transport layer 4 Light emitting layer 5 Cathode 6 Ideal light emitting layer 7 Anode 8 Hole transport layer 9 Polyimide 10 Light emitting discotic liquid crystal layer 11 Cathode 12 Luminous flux expanding means 12X Black paint 12C Square trapezoidal array 12R Reflective film 12T Base material 13A Polarizer 13B Polarizer 14 Liquid crystal cell 15 Organic EL device of the present invention 16 Light beam

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G02F 1/1335 530 G02F 1/1335 530 H05B 33/10 H05B 33/10 (72) Inventor Hide Nakamura 1150 Hazawacho, Kanagawa-ku, Yokohama-shi, Yokohama-shi Address Asahi Glass Co., Ltd. Central Research Laboratory (72) Inventor Ryo Takahashi 1150 Hazawa-cho, Kanagawa-ku, Yokohama-shi Asahi Glass Co., Ltd. Central Research Laboratory (72) Inventor Shinji Terazono 1150 Hazawa-cho, Kanagawa-ku, Yokohama Asahi Glass Co., Ltd. Central Research Laboratory

Claims (7)

[Claims] 1. An organic electroluminescent device comprising a luminescent discotic liquid crystal layer between an anode and a cathode. 2. The device according to claim 1, wherein the luminescent discotic liquid crystal is a discotic liquid crystal having a luminous ability and / or a discotic liquid crystal containing a luminescent material. 3. The device according to claim 1, wherein the luminescent discotic liquid crystal is oriented so that its optical axis is substantially perpendicular to the anode and the cathode. 4. The device according to claim 1, wherein the discotic liquid crystal of the luminescent discotic liquid crystal is a polymer. 5. A method for producing an organic electroluminescent device having a light emitting layer provided between an anode and a cathode, wherein the light emitting layer is made of a discotic liquid crystal having a light emitting ability and / or a discotic liquid crystal containing a light emitting material, and A method for producing an organic electroluminescent device, comprising forming a liquid crystal by polymerizing a low molecular discotic liquid crystal of the above. 6. A liquid crystal display device comprising the element according to claim 1 arranged on a side opposite to a viewer of the liquid crystal display element as a light source. 7. The liquid crystal display device according to claim 6, wherein an optical means for spreading a light beam at a wide angle is arranged on the observation side of the liquid crystal display element.