JP3483519B2 - Method for forming display pattern of organic EL element - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a display pattern (light emitting pattern) of an organic electroluminescence (EL) element. INDUSTRIAL APPLICABILITY The present invention is used for an organic EL element that performs light emission display with a fixed pattern.

[0002]

2. Description of the Related Art Conventionally, as a method of forming a display pattern in an organic EL element for performing light emission display with a fixed pattern, one electrode of an anode and a cathode and a light emitting layer are formed solid and the other electrode is displayed. There is known a method in which a voltage is applied only to a light emitting layer in a portion corresponding to a display pattern to cause light emission by forming the light into a pattern shape.
Further, in Japanese Unexamined Patent Publication No. 10-284254, an insulating layer patterned so as to have a through hole hollowed out in a display pattern shape is provided between both electrodes, and the insulating layer emits light other than the light emitting pattern. Organic E not to do
An L element is disclosed.

[0003]

All of the above-mentioned conventional techniques require a step of forming an electrode or an insulating layer in a predetermined pattern. Examples of this method include a method using a vapor deposition mask and a method using photolithography. But,
According to the method using the vapor deposition mask among them, when forming a pattern (for example, a double circular pattern) having another pattern independently located inside the annular pattern, one vapor deposition mask is used. Since it cannot be formed, a plurality of vapor deposition masks must be used to perform a plurality of vapor deposition steps. On the other hand, the photolithography method has a high degree of freedom in the pattern shape to be applied, but requires a lot of man-hours such as resist pattern formation, exposure, and etching, and there is a possibility that a resist residue may cause a light emission defect.

An object of the present invention is to provide a method for forming a display pattern of an organic EL element, which can form various display patterns by a simple process.

[0005]

In order to solve the above problems, a display pattern forming method for an organic EL device according to the first invention of the present invention is directed to a method of forming an organic EL film on a transparent substrate and then forming the organic EL film. It is characterized in that the high temperature mask is brought into contact with a predetermined part of the above to deactivate the light emission of the part.

A display pattern forming method for an organic EL element according to a second aspect of the present invention is the method of the first aspect, wherein the high temperature mask is brought into contact with the light emitting layer, hole transporting layer and electron transporting layer constituting the organic EL film. It is characterized in that the function of at least one of the layers is lost.

In the method for forming a display pattern of an organic EL element of the third invention, at least one organic layer constituting the organic EL film is formed on a transparent substrate, and then a high temperature mask is brought into contact with a predetermined portion of the organic layer. It is characterized in that the function of the organic layer of the portion is lost to deactivate the light emission of the portion of the organic EL film.

The present invention will be described in detail below. As the above-mentioned "transparent substrate", it is possible to use a substrate made of a material having transparency to such an extent that the visibility of characters, figures and the like due to light emission of the organic EL laminate is not impaired. Further, it is preferable that the organic EL element has strength enough to retain the shape of the surface layer of the organic EL element and has hardness such that the surface is not easily scratched. As such a substrate, besides glass, a substrate made of polyethylene terephthalate, polyether sulfone, polycarbonate or the like can be used. This transparent substrate may be colorless and transparent,
It may be a colored and transparent one colored in an appropriate color tone.

An "organic EL laminated film" is formed by laminating an anode, an organic EL film and a cathode on this transparent substrate. The organic EL film arranged between both electrodes includes at least a light emitting layer, and may have a hole transport layer and / or an electron transport layer in addition to this light emitting layer, and further has a hole injection layer and / or an electron transport layer. It may have an injection layer. Various known materials can be used as the materials forming the anode, the cathode, and the organic EL film. The method for forming each of these layers is a vacuum deposition method, a spin coating method, a casting method, a sputtering method,
It may be appropriately selected from the methods such as the LB method. In the present specification, each layer such as a light emitting layer, a hole transporting layer, an electron transporting layer, a hole injecting layer and an electron injecting layer which constitute the organic EL film is also referred to as an “organic layer”.

According to the method of the present invention, a display pattern is formed by bringing a high temperature mask into contact with a predetermined portion of the organic EL film and deactivating the light emission of the portion. This “deactivation of light emission” is imparted by contacting with a high temperature mask to any one of the organic layers forming the organic EL film (for example, at least one of a light emitting layer, a hole transporting layer and an electron transporting layer). It is caused by deterioration due to heat and loss of the original transport function, light emitting function, etc. of the organic layer. Here, "alteration" means
It means that the compound that constitutes the organic layer undergoes a structural change due to heat, or decomposes and volatilizes. The high temperature mask may be brought into direct contact with the organic EL film at the stage after the formation of the organic EL film and before the formation of the electrode on the organic EL film, or after the formation of the electrode on the organic EL film. Although it may be contacted through the electrode, it is preferable to directly contact the high temperature mask with the organic EL film before forming the electrode from the viewpoint of accuracy of the formed pattern.

If the organic layer (for example, at least one of the light emitting layer, the hole transport layer, the electron transport layer, etc.) that influences the light emission of the organic EL film is formed, the organic EL film is not formed. The hot mask may be contacted prior to completion.
If the function of the layer that influences the light emission is lost to a predetermined shape, an organic EL film in which the light emission of the corresponding portion is deactivated can be obtained even if the remaining organic layer is solidly formed thereon. Organic EL
When the high temperature mask is contacted before the film formation is completed, even if the previously formed organic layer is decomposed or carbonized by the contact of the high temperature mask, the organic layer is further formed on the electrode, so that the electrode is formed. There is an advantage that a short circuit between them can be prevented.

The above-mentioned "high temperature mask" means a mask member which is heated to a high temperature for use. The material is not particularly limited, but it is preferable to use a metal (for example, iron, aluminum, copper and alloys thereof) because of excellent moldability and heat resistance and easy heating of the entire mask uniformly. On the back surface or inside of the high temperature mask, a heating means such as a heater can be provided for the purpose of facilitating heating and temperature control of the high temperature mask. This high temperature mask has its outer shape (outline, presence of through holes, etc.) and surface (organic E
The organic EL film or the organic layer (hereinafter, collectively referred to as “organic E”) is formed due to unevenness or the like provided on the surface contacting the L film or the like.
L film etc. " ) Is defined in a predetermined shape. By removing the contact portion of the high temperature mask from the shape of the organic EL film or the like formed on the transparent substrate,
A display pattern having a desired shape is formed.

When the contact portion with the organic EL film or the like is defined by the unevenness provided on the surface of the high temperature mask,
The height difference between the contact portion and the non-contact portion is preferably 0.1 mm or more, and more preferably 0.5 to 5 mm. According to this method, a high temperature mask or the like in which a concave portion having a shape corresponding to the display pattern to be formed is formed,
A display pattern having an arbitrary shape can be formed by a simple method such as contacting with a solid organic EL film or the like. By forming the non-contact portion as a recess instead of a through hole, a double-circular pattern or the like can be produced using a single high temperature mask, unlike conventional vapor deposition masks and the like. The organic EL film or the like with which the high-temperature mask contacts may be solid or patterned, but from the viewpoint of workability during manufacturing, etc., it should be formed solid over at least a certain range. preferable. In this case,
The effect of process simplification by using the method of the present invention is well exhibited.

The temperature of the high temperature mask at the time of contact with the organic EL film or the like may be any temperature at which the function of the organic layer to be treated can be lost, for example, 150 to 500.
℃, preferably 180 ~ 480 ℃, more preferably 20
It is in the range of 0 to 450 ° C. If the treatment temperature is too low, the function of the organic layer cannot be sufficiently lost, or the contact time required to lose the function of the organic layer becomes long, and the accuracy of the obtained display pattern decreases. . On the other hand, if the processing temperature is unnecessarily raised, the energy efficiency is lowered, and when the high temperature mask is brought into contact after forming the organic EL film, the organic layer may be decomposed or carbonized to cause a short circuit between the electrodes. The contact time between the organic EL film and the high temperature mask varies depending on the heat resistance (temperature at which the function is lost) of the organic layer to be treated, the temperature of the high temperature mask during the treatment, etc., but is usually 1 to 100 seconds. Is preferred,
More preferably, it is 5 to 10 seconds. If the contact time is too short, the function of the organic layer cannot be sufficiently lost, and the degree of treatment tends to be uneven. If the contact time is too long, even the portion of the organic layer that is not in contact with the high temperature mask may lose its function due to heat conduction, and the dimensional accuracy of the obtained display pattern may deteriorate.

The method of the present invention can also be applied to an organic EL device containing a plurality of light emitting materials having different emission colors.
For example, when a display pattern of an organic EL element for full-color display in which a red light emitting layer, a blue light emitting layer, and a green light emitting layer are stacked is formed, the heat resistance of the light emitting material contained in each layer is red>blue> green. Then, first, a red light emitting layer is formed, a red display pattern is formed by a high temperature mask having a temperature r, and then a blue light emitting layer is formed on the red display pattern and a temperature b (b
A blue display pattern is formed by the high temperature mask of <r),
Further, a green light emitting layer is formed thereon and the temperature g (g <b)
The green display pattern may be formed by using the high temperature mask described in 1.

The method of the present invention is suitable as a method for forming a display pattern in a segment type organic EL display device, and is particularly preferably used for forming a display pattern having a minimum pattern size of 0.5 mm or more (more preferably 1 mm or more). It

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to Examples. (Example 1) In this example 1, a solid organic E was formed.
In this example, a high temperature mask is brought into contact with the L film to form a circular display pattern. As shown in FIG. 2, an anode 2 made of ITO was formed on a transparent substrate 1 made of soda-lime glass. Then, as shown in FIG. 3, an organic EL film 3 was formed solid on the anode 2 by a vacuum deposition method. This organic EL film 3 is, in order from the anode 2 side, a hole injection layer made of a copper phthalocyanine complex, a hole transport layer made of TPTE (triphenylamine tetramer), and a quinacridone doped with an aluminum quinolium complex as a host. Luminous layer,
An electron transport layer composed of an aluminum quinolium complex, and Li
An electron injection layer made of F (neither is shown) is laminated. The total thickness of the organic EL film 3 is about 150 nm.

As shown in FIG. 4, the high temperature mask 4 has a thickness of 5
It is made of an iron plate having a diameter of 3 mm, and a through hole 41 having a diameter of 3 mm is provided in the center thereof. This high temperature mask 4 is heated to 300 ° C. by a heater, and as shown in FIG.
The surface of the membrane 3 was contacted for 5 seconds. As a result, the organic EL film 3 is maintained in the light emitting function in the deactivated portion 31 where the high temperature mask 4 is in contact with the high temperature mask 4 and in the portion where the high temperature mask 4 is not in contact due to the through hole 41. And the light emitting section 32. The treatment with the high temperature mask was performed in a nitrogen atmosphere after releasing the vacuum in the vacuum chamber used for forming the organic EL film 3. After that, a cathode was formed on the organic EL film 3 by a conventionally known method, and a sealing member was attached with an adhesive to form an organic EL element. When a voltage was applied to this organic EL element and it was observed from the transparent substrate 1 side, as shown in FIG. 5, light was emitted in a circular shape with a diameter of 2.8 mm, and the light emission luminance was substantially uniform in each part within this circle. there were.

A circular display pattern is similarly formed when a high temperature mask 4'having a circular recess 42 is used instead of the high temperature mask 4 having a through hole 41 as shown in FIG. be able to.

(Embodiment 2) This embodiment 2 is an example in which a high temperature mask is brought into contact with a solid organic EL film to form a double circular display pattern. As shown in FIG. 7, the high temperature mask 5 is made of an iron plate having a thickness of 5 mm, and an outer peripheral groove 51 and an inner peripheral groove 52 having a depth of 1 mm and a width of 1 mm are provided in a central portion thereof. The radius at the center in the width direction is 5 mm for the outer peripheral groove 51 and 2 mm for the inner peripheral groove. That is, the distance between the inner peripheral edge of the outer peripheral groove and the outer peripheral edge of the inner peripheral groove is 2 mm.
Is. The high temperature mask 5 was heated to 300 ° C. and brought into contact with the organic EL film 3 for 5 seconds in the same manner as in Example 1. As a result, the organic EL film 3 was patterned into the deactivating portion 31 and the light emitting portion 32. After that, when an organic EL element was formed in the same manner as in Example 1 and a voltage was applied to observe from the transparent substrate 1 side, as shown in FIG. 8, the outer peripheral groove 51 and the inner peripheral groove 5 were formed.
Light was emitted in the shape of a double circle having a shape corresponding to 2, and the light emission luminance was substantially uniform in each part of this light emitting portion.

In the above-mentioned Examples 1 and 2, the organic EL is used.
The high temperature mask was contacted after the film formation was completed. However, during the formation of the organic EL film, for example, when the hole transport layer was formed, the high temperature mask was contacted to change the quality of the hole transport layer in a predetermined pattern. Alternatively, the hole transport layer and / or the light emitting layer may be altered in a predetermined pattern by contacting with a high temperature mask when the light emitting layer is formed. After that, an electron transport layer and an electron injection layer are formed to obtain an organic EL film in which the light emission of the altered portion is deactivated.

In the above-mentioned Examples 1 and 2, the organic EL is used.
A low molecular weight material was used as the material of each organic layer forming the film, and the vacuum deposition method was used for the film formation, but the method of the present invention is also applied to the patterning of the organic layer made of the polymer material. can do. As described above, an organic layer using a polymer material (polyphenylene vinylene, polyvinyl carbazole, etc.) can be formed uniformly and easily because a large-area uniform film can be formed easily by a spin coating method or the like. It is suitable for the method of the present invention in which a high temperature mask is brought into contact with the above organic EL film or the like to perform patterning.

[0023]

In the display pattern forming method of the present invention, a display pattern is formed by bringing a high temperature mask into contact with a predetermined portion such as a solid organic EL film to deactivate light emission. According to this method, even if the pattern has another pattern independently located inside the annular pattern (for example, a double circular pattern), it is possible to form a resist pattern or use a plurality of vapor deposition masks. It can be created without Therefore, the manufacturing process can be simplified and the patterning can be performed at low cost,
Further, the resist residue does not adversely affect the light emission. Further, in the method using the vapor deposition mask, it was difficult to form a uniform film because the thickness of the mask became a scar and the organic EL film at the end of the pattern was slightly thin, but the method of the present invention formed a solid film. A uniform film formation is easy because patterning may be performed later. Further, since there is no step between the portion forming the display pattern and the portion other than the display pattern in the light emitting layer, it is easy to uniformly form the cathode or the like on the light emitting layer.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state after a high temperature mask is brought into contact with an organic EL film in Example 1.

FIG. 2 is a perspective view showing a stage of forming an anode on a transparent substrate in Example 1.

FIG. 3 is a perspective view showing a stage in which an organic EL film is formed on an anode in Example 1.

4 is a perspective view showing a high temperature mask used in Example 1. FIG.

FIG. 5 is a plan view of the organic EL element manufactured according to Example 1 as viewed from the transparent substrate side during light emission.

FIG. 6 is a perspective view showing another high temperature mask usable in the first embodiment.

FIG. 7 is a perspective view showing a high temperature mask used in Example 2;

FIG. 8 is a plan view of the organic EL element manufactured according to Example 2 as viewed from the transparent substrate side during light emission.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1; Transparent substrate, 2; Anode, 3; Organic EL film, 31; Deactivating part, 32; Light emitting part, 4; High temperature mask, 41; Through hole,
5; high temperature mask, 51; outer peripheral groove, 52; inner peripheral groove.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 2001-76870 (JP, A) JP 8-259938 (JP, A) JP 9-306669 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H05B 33/00-33/28

Claims (3)

(57) [Claims] 1. After forming an organic EL film on a transparent substrate,
A method for forming a display pattern of an organic EL element, which comprises deactivating the light emission of a predetermined portion of the organic EL film by bringing it into contact with a high temperature mask. 2. The organic EL device according to claim 1, wherein the function of at least one layer of the light emitting layer, the hole transporting layer and the electron transporting layer that constitutes the organic EL film is lost by bringing the high temperature mask into contact. Method for forming display pattern of device. 3. At least one organic layer forming an organic EL film is formed on a transparent substrate, and then a high temperature mask is brought into contact with a predetermined portion of the organic layer so that the function of the organic layer in the portion is lost. The method for forming a display pattern of an organic EL element is characterized by deactivating the light emission of the part in the organic EL film.