JP2008270070A - Manufacturing method of light-emitting element array - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of uniformly and easily forming a linear light-emitting element array without need of complicated control. <P>SOLUTION: The manufacturing method of a linear light-emitting element array 1 with light-emitting elements linearly formed on a substrate 10 includes a pattern forming process forming a linear pattern A for coating organic EL material ink 19 on the substrate 10, a process of relatively moving a discharge port 4a capable of discharging the organic EL material solution 19 in a liquid injection state on the substrate 10 along the linear pattern A, and continuously pouring the liquid-injection organic EL material ink 19 from the discharge port 4a into the linear pattern A, and a process of drying the organic EL material ink 19 poured into the linear pattern A and forming a light-emitting layer 18. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a line-shaped light emitting element array, and more particularly to a method for manufacturing a light emitting element array using an organic EL as a light emitting element.

  Electrophotographic printers are used not only for printers but also for output devices of facsimile receivers and copiers, and their applications are expanding. This electrophotographic printer incorporates a printer head, and this printer head is used in an exposure process in which image information is written as a latent image on the surface of a photosensitive drum by a static charge during a printing process.

  There are two types of printer heads: laser beam (LB) scan method and LED array method. Among them, the LB scan method is difficult to miniaturize an optical system mainly composed of a rotating polyhedral mirror. LED array systems are becoming mainstream.

  Conventionally, the LED array system uses an LED array chip manufactured from an expensive GaAs compound semiconductor epitaxial substrate as a light emitting element, and a large number of LED array chips are arranged in the longitudinal direction of the light emitting element array by the length of the printing paper. A light emitting element array is formed. For this reason, the LED array type printer head has problems such as a complicated process due to handling a large number of LED array chips and an array error of the LED array chips.

  On the other hand, Patent Document 1 proposes a printer head using an organic EL material instead of a compound semiconductor as a light emitting element material. In the printer head described in Patent Document 1, organic EL elements are produced seamlessly on a substrate, and there is no problem of LED array chip alignment errors or connecting portions unlike the LED array system. Assembly and bonding wiring are not required, and cost can be reduced.

  As a method for forming a light emitting element array using an organic EL element as in Patent Document 1, a method of forming a film of an organic EL material by a vacuum evaporation method or the like, and a coating method of forming a film by applying an organic EL material solution (for example, , Spin coating method, ink jet method), but the coating method is simpler than the vacuum vapor deposition method and can be manufactured at low cost.

JP-A-8-48052

  However, when producing an elongated element such as a light-emitting element array of a printer head, the spin coating method has a problem that an unnecessary step is required after applying an organic EL material to the entire surface of the substrate, and a coating area. There is a problem that the ratio of the removal area to the substrate is large and the utilization efficiency of the raw material is lowered.

On the other hand, in the ink jet method, the organic EL material solution can be applied only to the light emitting portion of the light emitting element array of the printer head. Therefore, the unnecessary part removal step is not required, and the waste of raw materials can be reduced.
However, the inkjet method requires fine position control of the discharge port of the organic EL material solution in accordance with the position of each light emitting portion, and discharge timing control of the droplets of the organic EL material solution at the time of alignment. In order to uniformly form the light emitting element, there is a problem that very complicated control is required.

Furthermore, in the ink jet method, complicated control is required to discharge droplets from the discharge port in the vertical direction and to prevent the droplets from being split and scattered around the substrate and spreading. There was a problem.
As described above, the ink jet method requires complicated control, so that the coating apparatus becomes expensive, and the cost is increased as a whole.

  The present invention has been made to solve such a problem, and provides a manufacturing method capable of uniformly and easily producing a line-shaped light emitting element array without requiring complicated control. The purpose is to do.

  In order to achieve the above object, the present invention provides a method of manufacturing a line-shaped light emitting element array, a pattern forming step of forming a line-shaped pattern for applying an organic EL material solution on a substrate, The discharge port capable of discharging the organic EL material solution in the form of liquid injection is moved relative to the substrate along the line pattern, and the liquid injection type organic EL material solution is continuously transferred from the discharge port to the line pattern. And a step of forming an organic EL material layer by drying the organic EL material solution poured into the line pattern.

  According to the present invention thus configured, a line pattern for applying an organic EL material solution is prepared on a substrate in advance, and the organic EL material solution is continuously applied to the line pattern in a liquid column shape. Compared with the case where it is applied by the inkjet method, the organic EL material solution can be made difficult to be scattered outside the application region. In the present invention, since the organic EL material solution is continuously discharged from the discharge port, the position control and discharge control of the discharge port are simpler than the ink jet method, and the configuration of the coating apparatus can be simplified. it can.

  Preferably, in the present invention, in the pattern forming step, a parallel lined pattern is formed between the partition walls by forming parallel partition walls on the substrate. According to the present invention configured as described above, a line pattern can be easily formed by the partition wall. Moreover, the quantity of the organic EL material solution which can be arrange | positioned in a groove | channel can be adjusted by setting the space | interval of a partition part, height, etc. suitably.

  In the present invention, preferably, in the pattern forming step, a line pattern having a higher lyophilic property to the organic EL material solution than the surface of the substrate is formed on the surface of the substrate. According to the present invention configured as described above, when the organic EL material solution is continuously applied onto the highly lyophilic line pattern, the organic EL material solution is relatively more lyophilic than the line pattern. It is repelled in the surrounding area with low (relatively high liquid repellency) and collects on a line pattern with high lyophilicity. Thereby, it is possible to arrange the organic EL material solution on the line pattern without deviating from the line pattern.

Preferably, in the present invention, the pattern forming step includes a step of forming a line-shaped inorganic hole injection layer on the substrate, and a liquid repellent treatment of the surface of the substrate to surround the inorganic hole injection layer. Is formed on the surface having higher liquid repellency with respect to the organic EL material solution than the inorganic hole injection layer.
According to the present invention thus configured, since the inorganic hole injection layer is originally relatively lyophilic, it is difficult to repel the organic EL material solution, and the organic EL material solution is formed on the inorganic hole injection layer. Easy to place. In the present invention, the surface of the substrate including the inorganic hole injection layer is further treated for liquid repellency, so that the affinity for the organic EL material solution is reduced between the inorganic hole injection layer and the surrounding area. The organic EL material solution can be easily repelled in the peripheral region of the inorganic hole injection layer by increasing the difference in properties, and a linear pattern having higher lyophilicity than the peripheral region can be formed. .

Specifically, the inorganic hole injection layer can be formed of MoO ₃ , V ₂ O ₅ or a mixture thereof.

  According to the method for manufacturing a line-shaped light-emitting element array of the present invention, a line-shaped light-emitting element array can be uniformly and easily manufactured without requiring complicated control.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, a line-shaped light emitting element array according to a first embodiment of the present invention and a method for manufacturing the same will be described with reference to FIGS.
1 is a front view of a line-shaped light-emitting element array fabricated according to the first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1, and FIGS. FIG.

  As shown in FIGS. 1 and 2, a line-shaped light emitting element array 1 applied to a printer head includes a first electrode (anode) 12, an insulating layer 14, a partition wall 22, holes on a long and narrow substrate 10. The injection layer 16, the light emitting layer 18, and the second electrode (cathode) 20 are laminated in order.

  The line-shaped light-emitting element array 1 includes a large number of rectangular light-emitting portions 11 linearly arranged in a line, and is configured to irradiate light from the back surface (substrate 10 side) of the light-emitting portion 11 to the outside. ing. The interval between the light emitting units 11 is determined by the design resolution of the printer. The line-shaped light emitting element array 1 is configured to cause each light emitting unit 11 to emit light by a driving element (thin film transistor) (not shown) disposed on the lower side of the substrate 10.

  The substrate 10 is formed of a glass substrate that is transparent to a predetermined range of wavelength light. The substrate 10 only needs to be transparent, and is not limited to a glass substrate, and may be another transparent substrate. In addition, when the line-shaped light emitting element array 1 is configured to be irradiated with light from the light emitting layer 18 from the surface opposite to the substrate 10, the substrate 10 may not be transparent.

  The first electrode 12 is composed of a plurality of ITO thin films which are formed on the substrate 10 to have a film thickness of 10 nm to 10 μm and are rectangular in a plan view. The plurality of ITO thin films are arranged in a row as a whole while being separated from each other in the longitudinal direction of the substrate 10. Each ITO thin film is arranged with its longitudinal direction oriented in a direction perpendicular to the longitudinal direction of the substrate 10.

The first electrode 12 may be a conductive metal oxide film including an ITO thin film, a translucent metal thin film, or the like. Specifically, these forming materials are made of indium oxide, zinc oxide, tin oxide, and conductive glass made of indium / tin / oxide (ITO), indium / zinc / oxide, or the like, which is a composite thereof. The prepared film (NESA or the like), gold, platinum, silver, copper, or the like, preferably ITO, indium / zinc / oxide, or tin oxide.
The first electrode 12 may be an organic transparent conductive film such as polyaniline or a derivative thereof, polythiophene or a derivative thereof.

The first electrode 12 can be produced by a vacuum deposition method, a sputtering method, an ion plating method, a plating method, or the like.
The film thickness of the first electrode 12 is not limited to 10 nm to 10 μm, and may be appropriately selected in consideration of light transmission and electrical conductivity. The film thickness of the first electrode 12 is more preferably 20 nm to 1 μm, and further preferably 50 nm to 500 nm.
In order to facilitate charge injection on the first electrode 12, a layer made of a phthalocyanine derivative, a conductive polymer, carbon, or the like, or an average film thickness made of a metal oxide, a metal fluoride, an organic insulating material, or the like. A layer of 2 nm or less may be provided.

  The insulating layer 14 is a thin film made of photosensitive polyimide, and is formed so as to cover these surfaces except for part of the substrate 10 and the first electrode 12. A rectangular opening 15 is formed in the insulating layer 14 so as to expose a part of the surface of each first electrode 12. Each opening 15 defines a light emitting portion, and the plurality of openings 15 are arranged in a line array at a predetermined interval. The definition of the printer is determined by the interval between the openings 15.

The hole injection layer 16 is a MoO ₃ film and covers the opening 15 and a part of the insulating layer 14 around the opening 15 and is formed to extend continuously in the longitudinal direction of the substrate 10.
In addition to the MoO ₃ film, the hole injection layer 16 includes polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, a polysiloxane derivative having an aromatic amine in a side chain or a main chain, a pyrazoline derivative, an arylamine derivative, a stilbene derivative, From a hole transport material such as phenyldiamine derivative, polyaniline or derivative thereof, polythiophene or derivative thereof, polypyrrole or derivative thereof, poly (p-phenylene vinylene) or derivative thereof, or poly (2,5-thienylene vinylene) or derivative thereof. Can be formed.

The light-emitting layer 18 is a layer formed of a known organic light-emitting material. The light-emitting layer 18 overlaps with the hole injection layer 16 to cover the entire surface of the hole injection layer 16 and continuously extends in the longitudinal direction of the substrate 10. It is formed as follows.
The organic light emitting material forming the light emitting layer 18 is a compound having fluorescence and / or phosphorescence at room temperature, and may be a low molecule or a polymer. Preferably, a light emitting material having an emission spectrum that matches the spectral sensitivity of the photosensitive material used for the photosensitive drum is preferable. Moreover, it is preferable to have red light emission or light emission in the near infrared region.

  Examples of such organic light-emitting materials include naphthalene derivatives, anthracene or derivatives thereof, perylene or derivatives thereof, polymethine-based, xanthene-based, coumarin-based, cyanine-based pigments, 8-hydroxyquinoline or metal complexes of derivatives thereof. , Aromatic amines, tetraphenylcyclopentadiene or derivatives thereof, or tetraphenylbutadiene or derivatives thereof, distyryl biphenyl materials, dimesitylboryl materials, stilbene materials, dipyrylyl dicyanobenzene materials, benzoxazole materials, distyryl materials , Carbazole materials, dibenzochrysene materials, arylamine materials, pyrene-substituted oligothiophene materials, PPV oligomer materials, carbazole materials, polyfluorene materials, etc.

A triplet light emitting complex may be used as the organic light emitting material. Triplet light emitting complexes used as organic light emitting materials include, for example, Ir (ppy) ₃ , Btp ₂ Ir (acac) having iridium as a central metal, PtOEP having platinum as a central metal, and Eu (TTA having europium as a central metal. ₃ phen etc. are included.

The partition wall (bank) 22 is a photosensitive insulating material, and is formed on the insulating layer 14 in parallel with both sides of the opening 15. The partition wall portion 22 can be manufactured by a normal photolithography method.
The partition wall portion 22 is formed on the insulating layer 14 on both sides of the opening portion 15 at a height of 2 to 3 μm with an interval of about 140 μm, and a groove 23 is formed so that the opening portion 15 is the bottom. is doing. A line pattern A is defined by the two partition walls 22 so as to be sandwiched therebetween. The hole injection layer 16 and the light emitting layer 18 are formed so as to be laminated on the bottom of the groove 23 on the line pattern A.

The second electrode 20 is a thin film having a thickness of 10 nm to 10 μm formed of a Ba / Al alloy, covers the light emitting layer 18 and part of the partition 22 adjacent to the light emitting layer 18, and is continuous in the longitudinal direction of the substrate 10. Are formed to extend.
The material forming the second electrode 20 is preferably a material having a low work function including a Ba / Al alloy, such as lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, aluminum, scandium, Metals such as vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium, and two or more alloys thereof, or one or more of them, and gold, silver, platinum, copper, manganese, Including an alloy with one or more of titanium, cobalt, nickel, tungsten, tin, graphite, or a graphite intercalation compound. Examples of the alloy include a magnesium-silver alloy, a magnesium-indium alloy, a magnesium-aluminum alloy, an indium-silver alloy, a lithium-aluminum alloy, a lithium-magnesium alloy, a lithium-indium alloy, and a calcium-aluminum alloy. Note that the second electrode 20 may have a laminated structure of two or more layers.

The second electrode 20 can be produced by a vacuum deposition method, a sputtering method, a laminating method in which a metal thin film is thermocompression bonded, or the like.
The film thickness of the second electrode 20 is not limited to 10 nm to 10 μm, and may be appropriately selected in consideration of electric conductivity and durability. The film thickness of the second electrode 20 is more preferably 20 nm to 1 μm, and further preferably 50 nm to 500 nm.

In the present embodiment, the organic EL element has a configuration in which the first electrode 12, the hole injection layer 16, the light emitting layer 18, and the second electrode 20 are sequentially laminated on the substrate 10. Not limited to this, other known configurations may be adopted.
For example, an electron injection layer may be interposed between the light emitting layer 18 and the second electrode 20 in order to improve the effect of electron injection. The electron injection layer can be formed of a known electron injection layer material such as Ba, Ca, CaF, LiF, Li, or NaF. Further, a hole transport layer or an electron transport layer may be formed.

Further, a layer made of a conductive polymer or a layer made of a metal oxide, a metal fluoride, an organic insulating material or the like having an average film thickness of 2 nm or less may be provided between the second electrode 20 and the light emitting layer 18. . Furthermore, a protective layer may be provided so as to cover the second electrode 20.
In the present embodiment, the first electrode 12 is formed on the substrate 10 and the second electrode 20 is formed on the side far from the substrate 10. However, the present invention is not limited to this. The formation order may be selected depending on the element structure of the mold.

Next, a method for manufacturing the line-shaped light emitting element array according to the first embodiment will be described with reference to FIGS.
First, as shown in FIG. 3A, an ITO film 12a, which is a transparent conductive film, is formed on the substrate 10 in order to form the first electrode 12.
Next, as shown in FIG. 3B, the glass substrate 10 with the ITO film 12a is patterned by photolithography and etching. Thus, the first electrode 12 in which the ITO film 12a is patterned in a predetermined shape is formed on the substrate 10.

  After the first electrode 12 is formed, an insulating layer 14 having an opening 15 is formed as shown in FIG. A plurality of openings 15 exposing the first electrode 12 are arranged in an array in the longitudinal direction, forming an array-like light emission pattern. In this step, after the insulating layer 14 is formed of an inorganic insulating film made of photosensitive polyimide, the opening 15 is formed by photolithography.

  Next, as shown in FIG. 3D, partition walls 22 made of a photosensitive insulating material are formed on both sides of the arrayed light emitting pattern by photolithography (pattern forming step). The groove 23 formed by the partition wall portion 22 defines a line pattern A for forming a coating region into which an organic EL material solution (ink) is poured in a later process. The width of the groove 23 is set such that the organic EL material ink spreads over the entire surface within the bank width when the organic EL material ink is continuously applied by the nozzle coating method.

After the partition wall portion 22 is formed, a hole injection layer 16 made of a MoO ₃ film is formed between the partition wall portions 22 as shown in FIG. The width of the hole injection layer 16 may be approximately the same as the bank groove width.
In this step, first, the surface side of the substrate 10 is subjected to UV-ozone treatment to activate the surface of the ITO film (first electrode 12) exposed from the opening 15. Thereafter, using a shadow mask, the hole injection layer 16 is formed in a line along the longitudinal direction of the substrate 10 so as to completely cover the opening 15 along the groove 23 by mask vapor deposition.

Next, the light emitting layer 18 is formed on the hole injection layer 16.
In this step, first, an organic EL material liquid (ink) 19 is prepared as a material for forming the light emitting layer 18. In the organic EL material ink 19, for example, a red light emitting material (RP221 manufactured by Summation) is dissolved in a mixed solvent (mixing ratio, 50:50) made of anisole and cyclohexylbenzene to make 1 wt%. The viscosity of the ink is usually about 1 to 50 mPa · s.

In the present embodiment, as shown in FIG. 5, the organic EL material ink 19 is applied in the groove 23 using the line application device 3.
The line coating device 3 is connected to an ink storage tank (not shown) and is capable of ejecting the organic EL material ink 19, a controller 5 for controlling the operation of the nozzle 4 and the substrate 10, and a control signal of the controller 5 And a substrate feed mechanism (not shown) for moving the substrate 10 based on a control signal from the controller 5.

The controller 5 is configured to control the operation of the nozzle 4 and the substrate 10 according to the moving speed of the nozzle 4, the moving speed of the substrate 10, and the ink discharge flow rate from the nozzle 4 set in advance by the user. Further, the controller 5 specifies the relative position of the nozzle 4 with respect to the substrate 10 by the alignment mechanism and the position detection mechanism, and performs movement control of the nozzle 4 and the substrate 10 based on the specified position information.
The nozzle 4 has a discharge port 4 a having an inner diameter of 15 μm, and can discharge the organic EL material ink 19 from the discharge port 4 a continuously in a liquid column shape at a discharge flow rate set in the controller 5. .

  When the substrate 10 is set in such a line coating apparatus 3, the controller 5 specifies the position of the substrate 10 and the position of the nozzle 4, and the nozzle 4 is positioned more than one end side of the groove 23 formed in the substrate 10. Move upward outside. Then, the controller 5 continuously discharges the organic EL material ink 19 from the nozzle 4, the discharge flow rate of the organic EL material ink 19 discharged downward from the discharge port 4 a is stabilized, and the organic EL material ink 19. Until the nozzle 4 is in a steady liquid column state. In this embodiment, the ink feeding pressure is adjusted so that the discharge flow rate from the discharge port 4a is 100 microliters / minute.

  As shown in FIG. 5, when the organic EL material ink 19 is in a steady liquid column state, the controller 5 has a constant relative moving speed with respect to the substrate 10 from one end side to the other end side of the groove 23. To move the nozzle 4. In FIG. 5, the organic EL material ink 19 in a liquid column state is indicated by reference numeral 19a. In the present embodiment, the relative movement speed is set to 1 m / second. Thereby, the organic EL material ink 19 can be applied almost uniformly in the longitudinal direction of the substrate 10 in the groove 23.

FIG. 4B shows a state immediately after the organic EL material ink 19 is applied. As shown in FIG. 4B, the organic EL material ink 19 is filled in the groove 23, completely covers the upper part of the hole injection layer 16, and rises above the upper end of the groove 23 due to surface tension. It has become. Thus, the organic EL material ink 19 after nozzle coating is held in the line pattern A without being spread outside by the partition wall 22.
Further, in order to uniformly apply the organic EL material ink 19 in the longitudinal direction of the groove 23, the controller 5 causes the nozzle 4 to write the organic EL material ink 19 in the groove 23 (that is, the line pattern A) at a constant speed with a so-called single stroke. Apply.

  And after apply | coating the organic EL material ink 19 to the groove | channel 23, and carrying out a drying process, as shown in FIG.4 (C), as shown in FIG.4 (C), on the positive hole injection layer 16 in the groove | channel 23, a predetermined film | membrane A light emitting layer 18 which is a thick organic EL material layer is formed. In the present embodiment, the light emitting layer 18 having a film thickness of 100 nm was obtained. After drying, unnecessary portions formed outside the ends of the grooves 23 are removed.

  The film thickness of the light emitting layer 18 is determined by the relative movement speed of the discharge port 4a with respect to the substrate 10, the discharge flow rate, the solution concentration of the organic EL material ink 19, the width and height of the groove 23, and the like. Therefore, the film thickness of the light emitting layer 18 necessary for the predetermined light emission characteristics of the light emitting element is set, and the relative movement speed, the discharge flow rate, the solution concentration, and the shape of the partition wall 22 are determined from the set film thickness.

Next, as shown in FIG. 2, a Ba / Al alloy is pattern-deposited using a shadow mask in the groove 23 to form the second electrode 20. Thereby, the upper surface of the light emitting layer 18 and a part of the partition wall portion 22 are covered with the second electrode 20.
Furthermore, after forming the 2nd electrode 20, the line-shaped light emitting element array 1 can be produced by sealing the upper part of the groove | channel 23 with the glass substrate and epoxy resin adhesive which are not shown in figure.

  In the method for manufacturing the line-shaped light-emitting element array according to the first embodiment described above, the line-shaped pattern A for applying the organic EL material ink 19 is previously formed by the partition wall 22. In this embodiment, by injecting the organic EL material ink 19 into the groove 23 defined by the partition wall 22, the organic EL material ink 19 is surely applied onto the line pattern A, and is externally applied from the groove 23 (line pattern A). Can be prevented from spreading.

  Furthermore, in this embodiment, since the organic EL material ink 19 is in a liquid column state from the nozzle 4 and is applied continuously in the groove 23, the organic EL material ink sphere bursts as in the ink jet method. Can be prevented from being scattered and spreading outside.

  In this embodiment, since the organic EL material ink 19 is continuously applied from the nozzle 4 in a liquid column state, the nozzle 4 and the substrate 10 may be moved at a constant relative speed. There is no need to stop at the section 15. For this reason, it is possible to simplify the alignment of the nozzle 4 and the substrate 10, the operation control of the movement and discharge of the nozzle 4, and the configuration of the entire coating apparatus.

  In this embodiment, the organic EL material ink 19 is continuously applied from the nozzle 4 in a liquid column state, thereby stabilizing the discharge flow rate of the organic EL material ink 19 and stabilizing the discharge direction of the liquid column. Becomes easy. Thereby, in this embodiment, the organic EL material ink 19 is uniformly applied in the groove 23, and the thickness of the light emitting layer 18 is uniform without causing a deviation in the application amount in the longitudinal direction and the direction perpendicular thereto. Therefore, it is possible to easily equalize the light emission characteristics of the light emitting units 11 arranged in a line.

Next, a line-shaped light emitting element array and a method for manufacturing the same according to the second embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the same component as 1st Embodiment, and the overlapping description is abbreviate | omitted.
6 is a front view of a line-shaped light-emitting element array fabricated according to the second embodiment of the present invention, FIG. 7 is a sectional view taken along line VII-VII of FIG. 6, and FIGS. FIG.

Similar to the first embodiment, the line-shaped light-emitting element array 7 of the second embodiment has a first electrode 12, an insulating layer 14, a hole injection layer 16, a light-emitting layer 18, and a second electrode 20 on the substrate 10. Are sequentially stacked.
However, the line-shaped light emitting element array 7 of the second embodiment is different from that of the first embodiment in that the partition wall 22 is not formed on the insulating layer 14 and the surface of the insulating layer 14 is liquid repellent instead. Formed on the conductive surface 14a.

Next, a method for manufacturing the line-shaped light emitting element array according to the second embodiment will be described with reference to FIGS.
As shown in FIGS. 8A to 8C, first, the insulating layer 14 having the first electrode 12 and the opening 15 is formed on the substrate 10, and these steps are performed in the first embodiment (FIG. 8). 3 (A) to FIG. 3 (C)) and the description is omitted.

After the patterned insulating layer 14 is formed, a hole injection layer 16 made of a MoO ₃ film is formed so as to cover the opening 15 as shown in FIG. The width of the hole injection layer 16 is determined so that the opening 15 is completely covered and the organic EL material ink 19 does not overflow outside the hole injection layer 16 and has a predetermined thickness in a later step.

In this step, first, the surface side of the substrate 10 is subjected to UV-ozone treatment to activate the surface of the ITO film (first electrode 12) exposed from the opening 15. Thereafter, using a shadow mask having a width of 200 μm, the hole injection layer 16 is formed to extend in the longitudinal direction with a width of 200 μm on the openings 15 arranged in a line by mask vapor deposition.
The insulating layer 14, which is a photosensitive polyimide film, has liquid repellency (ink repellency) with respect to the organic EL material ink 19. On the other hand, a MoO ₃ film having high lyophilicity (ink affinity) for the organic EL material ink 19 is selected for the hole injection layer 16. Therefore, in this step, the hole injection layer 16 having a higher lyophilic property than the insulating layer 14 is formed in a line shape on the surface of the liquid repellent insulating layer 14.

Thus, the MoO ₃ film as the inorganic hole injection layer having high lyophilicity is selected for the hole injection layer 16. As the material having high lyophilicity, an inorganic oxide type hole injection material is preferable. For example, molybdenum oxide (MoO ₃ ) is particularly preferable, but in addition to this, vanadium pentoxide (V ₂ O ₅ ) or molybdenum oxide is used. A mixture of (MoO ₃ ) and vanadium pentoxide (V ₂ O ₅ ) can be selected.

Next, in order to increase the difference in affinity between the insulating layer 14 and the hole injection layer 16 with respect to the organic EL material ink 19, a liquid repellency treatment (ink repellency treatment) is performed on the surface of the substrate 10. The ink repellency process of this embodiment is a plasma process using CF ₄ gas. As the ink repellent treatment, there are a method of treating with plasma generated from a gas made of fluorine or a fluorine compound as described above, a method of exposing the substrate 10 to an atmosphere containing a gas made of fluorine or a fluorine compound, and the like.

The insulating layer 14 made of a photosensitive polyimide film has higher liquid repellency with respect to the organic EL material ink 19 than the hole injection layer 16 that is an inorganic hole injection layer. A material having high liquid repellency is selected. For the hole injection layer 16, a material that does not greatly change the degree of liquid repellency or lyophilicity by performing liquid repellency treatment is selected.
By performing the ink repellency treatment, the contact angle of the organic EL material ink 19 on the insulating layer 14 increases to 60 °, but the contact angle on the hole injection layer 16 remains about 10 °. The difference in affinity for the organic EL material ink 19 can be further increased. That is, the degree of lyophilicity of the lyophilic hole injection layer 16 is hardly changed by the ink repellency treatment, but the surrounding region becomes more lyophobic.

As a result, as shown in FIG. 9A, the lyophobic (ink repellency) is more lyophilic than the lyophobic surface 14a within the lyophobic surface 14a of the insulating layer 14 having liquid repellency (ink repellency). A hole injection layer 16 having a high surface is formed, and the line-shaped pattern B is defined by the hole injection layer 16.
In the present embodiment, the pattern forming step includes a step of forming with the lyophilic hole injection layer 16 and a step of subjecting the surface of the substrate 10 to a liquid repellent treatment.

  After the line-shaped pattern B is formed on the substrate 10, the liquid column state organic EL material ink 19 is continuously applied onto the line-shaped pattern B using the same line coating apparatus 3 as in the first embodiment. At this time, as shown in FIG. 9B, since the organic EL material ink 19 is easily repelled by the liquid repellent surface 14a of the insulating layer 14, it does not spread on the insulating layer 14 and is highly lyophilic. Collect on the hole injection layer 16. The maximum volume of the organic EL material ink 19 held on the hole injection layer 16 per unit length is determined by the affinity difference, the width of the hole injection layer 16, the ink solution concentration, and the like. The application conditions for the organic EL material ink 19 may be the same as those in the first embodiment.

And after apply | coating the organic EL material ink 19, it dries, and as shown in FIG.9 (C), as shown in FIG.9 (C), on the hole-injection layer 16, it is an organic EL material layer of predetermined thickness. A light emitting layer 18 is formed. In the present embodiment, the light emitting layer 18 having a film thickness of 100 nm was obtained.
As described above, in the present embodiment, a highly lyophilic line pattern B is formed in the lyophobic surface 14 a on the substrate 10, and the organic EL material ink 19 is applied to the lyophilic portion, thereby repelling the liquid. The light emitting layer 18 can be formed on the desired line pattern B without spreading the organic EL material ink 19 in the liquid portion.

After forming the light emitting layer 18, as shown in FIG. 7, the 2nd electrode 20 which consists of Ba / Al alloy is formed on the light emitting layer 18 by a vacuum evaporation method. The second electrode 20 is formed to extend in the longitudinal direction with a predetermined width by pattern deposition using a shadow mask so as to cover the openings 15 arranged in a line.
Finally, the region where the line-shaped light emitting layer 18 is formed is sealed with a glass substrate and an epoxy resin adhesive (not shown), and the line-shaped light emitting element array 7 is manufactured.

  In the method of manufacturing the line-shaped light emitting element array according to the second embodiment described above, the peripheral surface of the lyophilic hole injection layer 16 is changed to a liquid repellent surface 14a by ink repellent treatment in advance. B is formed. Thus, if the organic EL material ink 19 is ejected onto the line pattern B, the organic EL material ink 19 is held on the line pattern B without spreading the organic EL material ink 19 outside the line pattern B. I can leave. Thus, in the present embodiment, the light emitting layer 18 can be easily formed on the predetermined line pattern B without requiring complicated control.

  The second embodiment is the same as the first embodiment in that the light emitting layer 18 having a uniform film thickness in a line can be easily formed.

  In the above embodiment, the line-shaped light-emitting element array applicable to the printer head has been described. However, the present invention is not limited to this, and a line-shaped light-emitting element applied to other applications may be used.

It is a front view of the line-shaped light emitting element array by 1st Embodiment of this invention. It is the II-II sectional view taken on the line of FIG. It is a figure which shows the manufacturing process of the line-shaped light emitting element array by 1st Embodiment of this invention. It is a figure which shows the manufacturing process of the line-shaped light emitting element array by 1st Embodiment of this invention. It is a figure which shows the manufacturing process of the line-shaped light emitting element array by 1st Embodiment of this invention. It is a front view of the line-shaped light emitting element array produced by 2nd Embodiment of this invention. It is the VII-VII sectional view taken on the line of FIG. It is a figure which shows the manufacturing process of the line-shaped light emitting element array by 2nd Embodiment of this invention. It is a figure which shows the manufacturing process of the line-shaped light emitting element array by 2nd Embodiment of this invention.

Explanation of symbols

1, 7 Line-shaped light emitting element array 3 Line coating device 4 Nozzle 4a Discharge port 5 Controller 10 Substrate 11 Light emitting part 12 First electrode (anode)
14 Insulating layer 14a Liquid repellent surface 15 Opening 16 Hole injection layer 18 Light emitting layer 19 Organic EL material ink 20 Second electrode (cathode)
22 Partition 23 Groove A, B Line pattern

Claims (5)

A method of manufacturing a line-shaped light emitting element array,
A pattern forming step of forming a line pattern on the substrate for applying the organic EL material solution;
A discharge port capable of discharging an organic EL material solution into a liquid injection shape is moved relative to the substrate along the line pattern, and a liquid injection type organic EL material solution is discharged from the discharge port to the line pattern. A process of continuously pouring
And drying the organic EL material solution poured into the line pattern to form an organic EL material layer.   2. The light emitting device according to claim 1, wherein in the pattern forming step, the line-shaped pattern in a groove shape sandwiched between the partition walls is formed by forming parallel partitions on the substrate. A method for manufacturing an element array.   2. The light emitting device array according to claim 1, wherein in the pattern forming step, a line-shaped pattern having higher lyophilicity with respect to the organic EL material solution than the surface of the substrate is formed on the surface of the substrate. Method. The pattern forming step includes
Forming a linear inorganic hole injection layer on the substrate;
Forming a liquid repellent treatment on the surface of the substrate, and forming the periphery of the inorganic hole injection layer on a surface having a higher liquid repellency with respect to the organic EL material solution than the inorganic hole injection layer; The manufacturing method of the light emitting element array of Claim 1 characterized by the above-mentioned. Method of manufacturing a light emitting device array according to claim 4, characterized in that the inorganic hole injecting layer is formed by MoO _3, V ₂ O _5, or mixtures thereof.

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