JP2005332633A - Organic electroluminescence display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL display device having a long product life. <P>SOLUTION: This organic EL display device 100 includes: a substrate 110; a first electrode 120 formed on the substrate 110; an organic layered product 130 formed on the first electrode 120 and including a luminescent layer 132 and a hole transportation layer 131; and a second electrode 140 formed on the organic layered product 130. The luminescent layer 132 and/or the hole transportation layer 131 have/has a high scratch hardness above 2H. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an organic electroluminescence display device.

  In recent years, with the diversification of information processing equipment, there has been an increasing demand for flat display devices that consume less power than conventional cathode ray tubes (CRTs) and can be reduced in thickness. Examples of such a flat display device include a liquid crystal display device and an electroluminescence display device (hereinafter referred to as “EL display device”).

  Among them, the organic EL display device is self-luminous and has high visibility, is a complete solid-state device, has excellent impact resistance, and is easy to handle.

  FIG. 2 is a cross-sectional view of a conventional organic EL display device 200.

  The organic EL display device 200 includes a substrate 210, an organic stacked body 230 provided on the substrate 210, a first electrode 220 provided so as to sandwich the organic stacked body 230, a second electrode 240, Have.

  The first electrode 220 has a function of injecting holes into the organic stacked body 230. The second electrode 240 has a function of injecting electrons into the organic stacked body 230.

  The organic stacked body 230 includes a light emitting layer 232 containing organic light emitting molecules that emit light, and a hole transport layer 231 and an electron transport layer 233 provided so as to sandwich the light emitting layer 232.

  The hole transport layer 231 is interposed between the first electrode 220 and the light emitting layer 232 and has a function of transporting holes injected from the first electrode 220 to the light emitting layer 232. The electron transport layer 233 is interposed between the second electrode 240 and the light emitting layer 232 and has a function of transporting electrons injected from the second electrode 240 to the light emitting layer 232.

  Energy is generated by recombination of holes transported by the hole transport layer 231 and electrons transported by the electron transport layer 233 in the light emitting layer 232, and the energy is generated in the organic light emitting molecules included in the organic stacked body 230. The organic light emitting molecule is excited by being supplied. The organic light emitting molecule emits light when the excited organic light emitting molecule is deactivated to the ground state.

  By the way, the light emitting layer 232 does not emit light uniformly in the entire light emitting layer 232 but emits light with a light emission luminance distribution as shown in FIG. The main light emitting layer 232b shown in FIG. 2 is a layer that exhibits the strongest light emission luminance because recombination of holes and electrons occurs at the highest frequency among the light emitting layers 232. As the distance from the main light emitting layer 232b increases, the frequency of recombination of holes and electrons decreases, and the emission luminance also decreases.

  When the conventional organic EL display device 200 is energized, the component of the light emitting layer 232 flows out into the hole transport layer 231 or the electron transport layer 233 and the component of the hole transport layer 231 or the electron transport layer 233 is passed with time. Into the light emitting layer 232 (hereinafter, this phenomenon is referred to as “mixing”). When crossing occurs in the organic EL display device 200, there is a problem that the light emission efficiency in the light emitting layer 232 deteriorates and the light emission luminance decreases.

  Hereinafter, the principle that the light emission efficiency is deteriorated and the luminance of the organic EL display device 200 is lowered when the organic EL display device 200 is mixed will be described with reference to FIGS. 3 and 4.

  FIG. 3 is a schematic cross-sectional view showing the organic laminated body 230 portion of the organic EL display device 200 in a state where current is not applied.

  FIG. 4 is a schematic cross-sectional view showing the organic laminate 230 ′ portion of the organic EL display device 200 ′ in a state where the crossing layers 232 a ′ and 232 c ′ are formed by energization.

  As shown in FIG. 3, in the organic EL display device 200 that is not energized, the main light emitting layer 232b in which recombination of holes and electrons occurs most frequently is sufficiently isolated from the hole transport layer 231 and the electron transport layer 233. Has been. Therefore, in the vicinity of the main light emitting layer 232b, molecules that receive energy (hereinafter referred to as “recombination energy”) generated by recombination of holes and electrons in addition to organic light emitting molecules, holes, electrons, or There is no molecule that traps both of them and does not contribute to carrier transport and light emission (hereinafter referred to as “quenching molecule”). Therefore, the recombination energy is supplied with high efficiency to the organic light emitting molecules present in the light emitting layer 232. Therefore, the light emitting layer 232 has high light emission efficiency, and the organic EL always-on device 200 has high light emission luminance. In addition, as a quenching molecule | numerator, the molecule | numerator which forms not only the molecule | numerator contained in the hole transport layer 231 and the electron carrying layer layer 233 and those aggregates but the 1st electrode 220 or the 2nd electrode 240, and those molecules, for example And an association of organic molecules, an impurity contained in the organic EL display device 200 ′, an association of the impurity and an organic substance, and the like.

  However, as shown in FIG. 4, in the energized organic EL display device 200 ′, the component of the hole transport layer 231 ′ and the component of the light emitting layer 232 ′ are mixed and the component of the electron transport layer 233 ′ is When the crossing with the component of the light emitting layer 232 ′ occurs, the crossing layer 232a ′ and the crossing layer 232c ′ are formed.

  Even when the crossing layer 232a ′ and the crossing layer 232c ′ are formed, when the crossing layer 232a ′, the crossing layer 232c ′, and the main light emitting layer 232b ′ are sufficiently separated, the main light emission There are no quenching molecules around layer 232b ′. Accordingly, the recombination energy is supplied with high efficiency to the organic light emitting molecules present in the light emitting layer 232 '.

  However, when the organic EL display device 200 ′ is energized, the crossing layer 232a ′ and the crossing layer 232c ′ grow, and the distance between the main light emitting layer 232b ′ and the crossing layer 232a ′ and the crossing layer 232c ′ is increased. When approaching, some of the recombination energy is not supplied to the organic light emitting molecules present in the light emitting layer 232 ′, but is supplied to the quenching molecules. By supplying recombination energy to the quenching molecule, the quenching molecule becomes excited. However, quenching molecules are not deactivated from the excited state to the ground state via the light emission process, unlike the organic light emitting molecules, and from the excited state to the ground state via a deactivation process other than the light emission process such as an exothermic process. Deactivated. Thus, the quenching molecule does not emit light when recombination energy is supplied. Accordingly, as the efficiency of supplying recombination energy to the quenching molecule increases, that is, as the efficiency of supplying recombination energy to the organic light emitting molecule decreases, the light emission efficiency of the light emitting layer 232 ′ decreases, and the organic EL display device 200 The emission brightness of 'also decreases.

  Further, the probability that quenching molecules are present around the main light emitting layer 232b ′ is that the crossing layer 232a ′ and the crossing layer 232c ′ grow, and the distance between the crossing layer and the main light emitting layer 232b ′ is It increases as it gets closer. Therefore, as the crossing layer 232a 'and the crossing layer 232c' grow, the proportion of recombination energy supplied to the quenching molecule increases. Accordingly, as the crossing layer 232a ′ and the crossing layer 232c ′ grow and the layer thickness of these layers increases, the light emission efficiency of the light emitting layer 232 ′ further decreases, and the light emission luminance of the organic EL display device 200 ′ also increases. Further decrease. In addition, when a portion in the light emitting layer 232 ′ whose light emission luminance is remarkably lowered so that light emission cannot be visually recognized from outside the organic EL display device 200 ′, the portion becomes a non-light emitting region called a dark spot.

  The present invention has been made in view of such a point, and the object of the present invention is to reduce the light emission luminance of the light emitting layer and reduce the light emitting layer by suppressing the crossing between the light emitting layer and the layer in contact with the light emitting layer. An object of the present invention is to provide an organic EL display device having a long product life by effectively suppressing deterioration of display quality due to an increase in a non-light emitting region called a dark spot.

An organic EL display device according to the present invention includes a substrate,
A first electrode provided on the substrate;
An organic laminate including a light emitting layer and an organic layer laminated so as to be in contact with the light emitting layer, provided on the first electrode;
A second electrode provided on the organic laminate,
The light emitting layer and / or the organic layer has a scratch hardness defined by JIS K 5600-5-4 of 2H or more.

  In the organic EL display device according to the present invention, the scratch hardness (hereinafter referred to as “hereinafter referred to as“ scratch hardness ”) defined in JIS K 5600-5-4 of at least one of the light emitting layer and the organic layer laminated so as to be in contact with the light emitting layer. The “scratch hardness” defined in JIS K 5600-5-4 is referred to as “scratch hardness”.

  When the light emitting layer is formed with a scratch hardness of 2H or more, the physical and chemical bonds of molecules in the light emitting layer are strong. Therefore, the outflow of the components of the light emitting layer to the layer in contact with the light emitting layer can be effectively suppressed. At the same time, the inflow of the component of the layer in contact with the light emitting layer to the light emitting layer can be effectively suppressed. In addition, when the organic layer laminated so as to be in contact with the light emitting layer is formed with a scratch hardness of 2H or more, the physical and chemical bonds of molecules in the organic layer are strong. Therefore, it can suppress effectively that the component of the organic layer flows into a light emitting layer. At the same time, it is possible to effectively suppress the components of the light emitting layer from flowing into the organic layer.

  Thus, in the organic EL display device according to the present invention, the crossing between the light emitting layer and the organic layer laminated so as to be in contact with the light emitting layer is effectively suppressed. Accordingly, it is possible to effectively suppress deterioration in display quality due to a decrease in light emission luminance of the light emitting layer and an increase in a non-light emitting region called a dark spot in the light emitting layer, and to realize an organic EL display device having a long product life. Can do.

  In the present invention, the light emitting layer and / or the organic layer may contain an organic polymer compound.

  The organic layer containing an organic polymer compound can be formed by a wet process such as an inkjet method that can be performed at a relatively low cost as compared with a dry process such as a vapor deposition method and enables high-precision patterning. Therefore, according to this structure, the light emitting layer and / or the organic layer laminated so as to be in contact with the light emitting layer can be formed by a wet process. Therefore, the light emitting layer and / or the organic layer laminated so as to be in contact with the light emitting layer can be formed at low cost, and can be patterned with high accuracy. Therefore, an organic EL display device having a light emitting layer having high-precision patterning and / or an organic layer stacked so as to be in contact with the light emitting layer can be easily and inexpensively manufactured.

  In addition, the light emitting layer and / or the organic layer containing the organic polymer compound is less likely to be modified by the treatment such as heating, for example, the organic polymer compound is crystallized. Therefore, a wide range of treatment methods such as heat treatment can be selected in order to cure the light emitting layer and / or the organic layer and improve the scratch hardness.

The method for manufacturing an organic EL display device according to the present invention includes a substrate, a first electrode provided on the substrate, a light emitting layer provided on the first electrode, and the light emitting layer. An organic electroluminescent display device comprising: an organic laminate including a laminated organic layer; and a second electrode provided on the organic laminate,
An organic laminate forming step of forming the organic laminate including the light emitting layer and the organic layer on the first electrode provided on the substrate,
The organic laminate forming step includes a curing step for curing the light emitting layer and / or the organic layer.

  According to this manufacturing method, it has the organic layer hardening step which hardens the organic layer laminated | stacked so that the light emitting layer and / or light emitting layer which were formed in the organic laminated body formation step may be contact | connected. Therefore, the scratch hardness of at least one of the light emitting layer and the organic layer laminated so as to be in contact with the light emitting layer can be improved.

  In the light emitting layer having a high scratch hardness, physical and chemical bonds of molecules in the light emitting layer are strong. Therefore, the outflow of the components of the light emitting layer to the organic layer in contact with the light emitting layer can be effectively suppressed. At the same time, the inflow of components such as an organic layer in contact with the light emitting layer into the light emitting layer can be effectively suppressed. Further, in an organic layer laminated so as to be in contact with a light emitting layer having a high scratch hardness, physical and chemical bonds of molecules in the organic layer are strong. Therefore, it can suppress effectively that the component of the organic layer flows into a light emitting layer. At the same time, the components of the light emitting layer can be prevented from flowing into the organic layer.

  Thus, in the organic EL display device manufactured by the manufacturing method according to the present invention, the crossing between the light emitting layer and the organic layer laminated so as to be in contact with the light emitting layer is effectively suppressed. Therefore, according to the method for manufacturing an organic EL display device according to the present invention, it is difficult to cause deterioration in display quality due to a decrease in light emission luminance of the light emitting layer and an increase in a non-light emitting region called a dark spot in the light emitting layer, and a product life span. A long organic EL display device can be provided.

  As described above, according to the present invention, the light emission luminance of the light emitting layer can be reduced or reduced by effectively suppressing the crossing between the light emitting layer and the organic layer or electrode laminated so as to be in contact with the light emitting layer. Since deterioration in display quality due to an increase in the light emitting area can be effectively suppressed, a long product life can be realized.

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

  FIG. 1 is a cross-sectional view of an organic EL display device 100 according to the present invention.

  The organic EL display device 100 includes a substrate 110, an organic stacked body 130 provided on the substrate 110, and a first electrode 120 and a second electrode 140 provided so as to sandwich the organic stacked body 130. .

  In the organic EL display device 100, holes and electrons injected from the first electrode 120 and the second electrode 140 are recombined in the light emitting layer 132. The energy generated by the recombination of holes and electrons is supplied to the organic light emitting molecules contained in the light emitting layer 132, and the organic light emitting molecules are excited. The excited organic light emitting molecules are deactivated to the ground state via a light emission process, whereby the light emitting layer 132 emits light.

  The substrate 110 can be formed of, for example, an inorganic material such as quartz, soda glass, or a ceramic material, or an organic material such as polyimide or polyester, but has sufficient strength to support the organic EL display device 100. If it has, it will not be limited at all.

  In addition, a driver circuit such as an active matrix circuit including TFTs may be formed on the substrate 110 as necessary. According to this configuration, it is possible to realize the organic EL display device 100 capable of high-quality and large-capacity display with favorable panel luminance and response.

The first electrode 120 has a function of injecting holes into the organic stacked body 130. The first electrode 120 can be made of, for example, indium tin oxide (ITO), tin oxide (SnO ₂ ), Au, Ni, Pt, or the like, but is not limited thereto.

  The first electrode 120 is not limited to a single layer structure. For example, a layer made of a material having high light reflectance such as Ag or Al, and an indium tin oxide having a high work function ( Of course, it may be formed in a multilayer structure with a layer made of ITO or indium zinc oxide (IZO).

In addition, when the organic EL display device 100 is a bottom emission method in which the light emission of the organic laminate 130 is extracted from the first electrode 120 side, the first electrode 120 is, for example, indium tin from the viewpoint of improving the light emission extraction efficiency. It is preferable to use a thin film of a material having a high work function such as oxide (ITO) or tin oxide (SnO ₂ ) and having high light transmittance. On the other hand, when the organic EL display device 100 is a top emission type in which the light emission of the organic stacked body 130 is extracted from the second electrode 140 side, the first electrode 120 has a high work function from the viewpoint of improving the light emission extraction efficiency. It is preferable to use a thin film of a material having high light reflectivity.

  The organic laminate 130 includes a hole transport layer 131 and a light emitting layer 132.

  The hole transport layer 131 is not limited as long as the hole injection efficiency is good. Examples of the material for the hole transport layer 131 include a triphenylamine inducer, polyparaphenylene vinylene (PPV) inducer, poly N vinyl carbazole (PVK), polyaniline, 3,4-polyethylenedioxythiophene / polystyrene sulfone. Examples thereof include organic materials such as nate (PEDOT / PSS) and polyfluorene derivatives, and p-type semiconductor materials, but are not limited thereto.

  The light emitting layer 132 is not particularly limited. For example, an 8-hydroxyquinolol inducer, a thiazole inducer, a benzoxazole inducer, a quinacridone inducer, a styrylarylene inducer, a perylene inducer, an oxazole inducer, an oxazol inducer, Diazole attractant, triazole attractant, triphenylamine attractant, fluorescent metal complex, polyparaphenylene vinylene (PPV) attractant, polyvinyl N carbazole (PVK), polyfluorene attractant, polythiophene attractant, spiro compound, etc. Can be formed. Two or more of these materials may be combined, or additives such as dopant materials may be combined. Examples of the dopant material include, but are not limited to, a coumarin inducer, a quinacridone inducer, a known laser dye, and the like.

  Further, the hole transport layer 131 and the light emitting layer 132 may contain an organic polymer compound. According to this configuration, the hole transport layer 131 and the light emitting layer 132 can be formed at a relatively low cost compared to a dry process such as a vapor deposition method, and formed by a wet process such as an inkjet method that enables highly accurate patterning. can do. Therefore, the hole transport layer 131 and the light emitting layer 132 can be formed at low cost, and can be patterned with high accuracy. Therefore, the organic EL display device 100 having the hole transport layer 131 and the light emitting layer 132 having high-precision patterning can be easily and inexpensively manufactured.

  Further, according to this configuration, even when the hole transport layer 131 and the light emitting layer 132 are subjected to heat treatment or the like, for example, the modification of the hole transport layer 131 and the light emitting layer 132 such that the organic polymer compound is crystallized. Hard to occur. Therefore, a wide processing method such as heat treatment can be selected to cure the hole transport layer 131 and the light emitting layer 132 and improve the scratch hardness.

  In the organic EL display device 100, the scratch hardness of at least one of the light emitting layer 132 and the hole transport layer 131 is 2H or more. When the light emitting layer 132 is formed with a scratch hardness of 2H or more, the physical and chemical bonds of molecules in the light emitting layer 132 are strong. Therefore, the outflow of the components of the light emitting layer 132 to the hole transport layer 131 and the second electrode 140 can be effectively suppressed. At the same time, the inflow of the components of the hole transport layer 131 and the second electrode 140 into the light emitting layer 132 can be effectively suppressed. When the hole transport layer 131 is formed with a scratch hardness of 2H or higher, the physical and chemical bonds of molecules in the hole transport layer 131 are strong. Therefore, it is possible to effectively suppress the components of the hole transport layer 131 from flowing into the light emitting layer 132. At the same time, it is possible to effectively suppress the components of the light emitting layer 132 from flowing into the hole transport layer 131.

  As described above, in the organic EL display device 100, the crossing between the light emitting layer 132, the hole transport layer 131, and the second electrode 140 is effectively suppressed. Accordingly, it is possible to effectively suppress deterioration in display quality due to a decrease in light emission luminance of the light emitting layer 132 and an increase in a non-light emitting region called a dark spot in the light emitting layer 132, and the organic EL display device 100 having a long product life can be obtained. Can be realized.

  Note that the hole transport layer 131 has a multilayer structure having a two-layer structure of a hole transport first layer in contact with the first electrode 120 and a hole transport second layer in contact with the light emitting layer 132, and the hole transport second layer is scratched. The hardness may be 2H or more. Since the crossing of the hole transport layer 131 and the light emitting layer 132 occurs at the contact surface between the hole transport layer 131 and the light emitting layer 132, the entire hole transport layer 131 does not necessarily have a scratch hardness of 2H or more. By setting only the scratch hardness of the second hole transport layer in contact with the layer 132 to 2H, the same effect as that obtained when the scratch hardness of the entire hole transport layer 131 is set to 2H or more can be obtained.

  Similarly, the light-emitting layer 132 may have a multilayer structure, and the scratch hardness of a layer in contact with the hole transport layer 131 among the layers constituting the light-emitting layer 132 may be 2H or more. In addition, only the scratch hardness of the layer constituting the light emitting layer 132 between the layer in contact with the hole transport layer 131 and the layer in contact with the second electrode 140 may be 2H or more.

  In addition, as a result of sincerity research by the inventor according to the present invention, it is known that the light emission luminance of the organic EL display device 100 is remarkably lowered when the thickness of the crossing layer grows to 30 nm or more. Therefore, the layer thickness of the layer in contact with the hole transport layer 131 among the second hole transport layer and the light emitting layer 132 is more preferably 0.01 to 50 nm.

  Further, in the organic EL display device 100, the organic stacked body 130 has a two-layer structure of the hole transport layer 131 and the light emitting layer 132, but is not limited to this configuration. That is, the organic stacked body 130 may have a single layer structure including only the light emitting layer 132. Of course, the organic laminate 130 may be configured by one or more of the hole transport layer 131, the hole injection layer, the electron injection layer, and the electron transport layer, and the light emitting layer 132.

  For example, in the case of an organic EL display device composed of a light emitting layer and a hole transport layer and an electron transport layer provided so as to sandwich the light emitting layer between the light emitting layer, the light emitting layer, the hole transport layer, or the electron transport layer Any one or more layers may be formed with a scratch hardness of 2H or more. For example, when the scratch hardness of the electron transport layer is configured to be 2H or more, the crossing of the electron transport layer and the light emitting layer and the crossing of the electron transport layer and the second electrode can be suppressed. Therefore, the energy generated by the recombination of holes and electrons can be maintained for a long time in a state where the energy is efficiently supplied to the organic light emitting molecules contained in the light emitting layer. Therefore, this organic EL display device can realize a long product life.

  The second electrode 140 has a function of injecting electrons into the organic stacked body 130. The second electrode 140 can be formed of a thin film such as Mg, Li, Ca, Ag, Al, In, Ce, or Cu, but is not limited thereto.

  The second electrode 140 is not limited to a single layer structure. For example, the second electrode 140 is formed of a layer made of a conductive and high light transmittance material such as indium tin oxide (ITO) and a Ca having a low work function. Of course, it may be formed in a multilayer structure with a layer made of Li or Li.

  Further, in the case where the organic EL display device 100 is a top emission type in which the light emission of the organic laminate 130 is extracted from the second electrode 140 side, the second electrode 140 is made light transmissive from the viewpoint of improving the light emission extraction efficiency. It is preferable to configure. On the other hand, when the organic EL display device 100 is a bottom emission method in which the light emitted from the organic laminate 130 is extracted from the first electrode 120 side, the second electrode 140 is made light reflective from the viewpoint of improving the light extraction efficiency. It is preferable to configure.

  Further, in the organic EL display device 100, a partition that partitions the first electrode 120, the organic stacked body 130, and the second electrode 140 into each pixel (or each pixel) may be provided on the substrate 110. By providing the partition walls, vertical leaks and crosstalk can be prevented, and mixing of the organic stacked body 130 between each pixel (or picture element) can be prevented.

As a material for the partition wall, an inorganic material such as SiO ₂ or SiN _x or an organic material such as polyimide or a photoresist can be used, but the material is not limited to this.

  In the organic EL display device 100, sealing may be provided on the substrate 110 so as to cover the first electrode 120, the organic stacked body 130, and the second electrode 140. The organic EL display device 100 can effectively suppress the ingress of moisture and oxygen into the organic EL display device 100 by providing a seal where the image display performance is greatly deteriorated due to the ingress of moisture and oxygen. In addition, the organic EL display device 100 having a long product life can be realized.

  As the sealing, a thin film made of an inorganic or organic material excellent in waterproofness, moisture proofing and oxygen resistance, a cap made of an inorganic material such as glass or metal can be used, but it is not limited to this. .

  From the viewpoint of preventing moisture and oxygen from entering the organic EL display device 100 more effectively, it is more preferable to form a seal in dry nitrogen or dry argon.

  Hereinafter, a method for manufacturing the organic EL display device 100 will be described.

  First, a film of indium tin oxide (ITO) or the like is formed on a substrate 110 such as glass by a known method such as a sputtering method, and is patterned by a photolithographic technique to form the first electrode 120.

  Next, the substrate 110 on which the first electrode 120 is formed is cleaned by performing IPA ultrasonic cleaning, IPA vapor cleaning, cleaning with UV ozone or oxygen plasma, and the like.

  Next, a hole transport material such as 3,4-polyethylenedioxythiophene / polystyrene sulfonate (PEDOT / PSS) is formed on the substrate 110 on which the first electrode 120 is formed by a known film formation method such as a spin coating method. Hole transport layer 131 is formed.

  The hole transport layer 131 can be formed to have a desired scratch hardness, for example, by performing a heat treatment at a desired temperature after film formation (curing step). However, the method for curing the hole transport layer 131 is not limited to this method. For example, the hole transport layer 131 contains a crosslinkable hole transport polymer so that a cross-linked structure is formed in the hole transport layer 131. The hole transport layer 131 may be cured by forming the film.

  Thus, by forming the hole transport layer 131 to have a scratch hardness of 2H or more by the curing step, the crossing of the hole transport layer 131 and the light emitting layer 132 can be effectively suppressed. Therefore, it is possible to effectively suppress a decrease in light emission luminance of the light emitting layer 132 and generation of a non-light emitting region called a dark spot in the light emitting layer 132, and the organic EL display device 100 having a long product life can be manufactured. .

  Of course, the hole transport layer 131 may be formed in a multilayer structure. When the hole transport layer 131 is formed in a multilayer structure, at least only the layer in contact with the light emitting layer 132 among the layers constituting the hole transport layer 131 is cured by heating or the like, so that the entire hole transport layer 131 is cured by a curing step. As in the case of the above, the crossing between the hole transport layer 131 and the light emitting layer 132 can be effectively suppressed. Therefore, it is possible to effectively suppress a decrease in light emission luminance of the light emitting layer 132 and generation of a non-light emitting region called a dark spot in the light emitting layer 132, and the organic EL display device 100 having a long product life can be manufactured. .

  Next, on the substrate 110 on which the hole transport layer 131 is formed, a light emitting material such as a blue light emitting polyfluorene-based material dissolved in xylene is formed by a known film forming method such as a spin coating method to form a light emitting layer. The organic laminated body 130 is formed by forming a film 132 (organic laminated body forming step).

  For example, the light emitting layer 132 can be cured by heat treatment or the like, and a desired scratch hardness can be obtained (curing step). However, the method of curing the light emitting layer 132 is not limited to this method. For example, a crosslinkable hole transport polymer is included in the light emitting layer 132 to form a crosslinked structure in the light emitting layer 132. Thus, the light emitting layer 132 may be cured. Thus, by forming the light emitting layer 132 to have a scratch hardness of 2H or more by the curing step, it is possible to effectively prevent the hole transport layer 131 and the second electrode 140 from intermingling with the light emitting layer 132. Therefore, it is possible to effectively suppress a decrease in light emission luminance of the light emitting layer 132 and generation of a non-light emitting region called a dark spot in the light emitting layer 132, and the organic EL display device 100 having a long product life can be manufactured. .

  Of course, the light emitting layer 132 may be formed in a multilayer structure. In the case where the light emitting layer 132 is formed in a multilayer structure, among the layers constituting the light emitting layer 132, the layer in contact with the hole transport layer 131 is cured by heating or the like, so that the entire light emitting layer 132 is cured by the curing step. In addition, the crossing of the hole transport layer 131 and the light emitting layer 132 can be effectively suppressed. Similarly, among the layers constituting the light emitting layer 132, the layer in contact with the second electrode 140 is cured by heating or the like, so that the second electrode 140 and the light emitting layer are cured in the same manner as when the entire light emitting layer 132 is cured by the curing step. The crossing with 132 can be effectively suppressed. Therefore, it is possible to effectively suppress a decrease in light emission luminance of the light emitting layer 132 and generation of a non-light emitting region called a dark spot in the light emitting layer 132, and the organic EL display device 100 having a long product life can be manufactured. .

  Next, Ca or the like is formed on the substrate 110 on which the organic multilayer layer 130 composed of the hole transport layer 131 and the light emitting layer 132 is formed by a film formation method such as sputtering, and the second electrode 140 is formed. The organic EL display device 100 can be manufactured by forming the above.

  Example 1 An indium tin oxide (ITO) film was formed on an insulating substrate by a known method and patterned by a photolithographic technique or the like to form a first electrode. The insulating substrate on which the first electrode was formed was subjected to IPA ultrasonic cleaning and IPA vapor cleaning, and then UV ozone cleaning was further performed for 30 minutes to clean the insulating substrate on which the first electrode was formed.

  A film of 3,4-polyethylenedioxythiophene / polystyrene sulfonate (hereinafter referred to as “PEDOT / PSS”) is formed on the insulating substrate on which the first electrode is formed, and heated at 210 ° C. for 10 minutes. As a result, a hole transport layer was formed. The layer thickness of the hole transport layer was 65 nm. Moreover, when the scratch hardness of the hole transport layer was measured by the method defined by JIS K 5600-5-4, it was H (hereinafter, the scratch hardness values shown in Examples and Comparative Examples are JIS K 5600-5). The value obtained by measuring by the method defined in -4 is shown).

  Next, a light emitting layer was formed by spin coating on a blue light emitting polyfluorene-based material dissolved in xylene on an insulating substrate on which a hole transport layer was formed, thereby forming an organic laminate.

  Next, the light emitting layer was cured by heating and drying the insulating substrate on which the light emitting layer was formed at 130 ° C. for 1 hour in a nitrogen atmosphere. The scratch hardness of the light emitting layer after the heat treatment was 2H.

  Next, the insulating substrate on which the organic laminate was formed was moved to a metal chamber, and LiF, Ca, and Ag were formed to have a thickness of 1 nm, 1.25 nm, and 100 nm, respectively, thereby forming a second electrode.

  Next, the insulating substrate on which the second electrode is formed is sealed with a glass sealing cap so as to cover the first electrode, the organic laminate composed of the hole transport layer and the light emitting layer, and the second electrode. Thus, an organic EL display device was produced.

  Next, the luminance half time from the predetermined luminance of the produced organic EL display device was measured.

  Table 1 shows the luminance half time from the predetermined luminance of the organic EL display device according to Example 1.

  (Example 2) An organic EL display device was prepared by the same method as in Example 1 except that the insulating substrate on which the light emitting layer was formed was heated at 200 ° C for 1 hour in a nitrogen atmosphere. Was measured.

  The layer thickness of the hole transport layer was 65 nm. The scratch hardness of the hole transport layer was H.

  Moreover, the scratch hardness of the light emitting layer after heat processing was 3H.

  Table 1 shows the luminance half time from the predetermined luminance of the organic EL display device according to Example 2.

  Example 3 First, a first electrode and a hole transport layer were formed on an insulating substrate by the same method as in Example 1. The layer thickness of the hole transport layer was 65 nm. The scratch hardness of the hole transport layer was H.

  Next, an organic laminated body was formed by forming a light emitting layer by spin coating with a green light emitting polyfluorene-based material dissolved in xylene on an insulating substrate on which a hole transport layer was formed.

  Next, the light emitting layer was cured by heating and drying the insulating substrate on which the light emitting layer was formed at 200 ° C. for 1 hour in a nitrogen atmosphere. The scratch hardness of the light emitting layer after the heat treatment was 2H.

  Next, the insulating substrate on which the organic laminate was formed was moved to a metal chamber, and a second electrode was formed by forming Ca and Ag with a layer thickness of 1.25 nm and 100 nm, respectively.

  Next, the insulating substrate on which the second electrode is formed is sealed with a glass sealing cap so as to cover the first electrode, the organic laminate composed of the hole transport layer and the light emitting layer, and the second electrode. Thus, an organic EL display device was prepared, and a luminance half time from a predetermined luminance was measured.

  Table 2 shows the luminance half time from the predetermined luminance of the organic EL display device according to Example 3.

  (Example 4) First, a first electrode, a hole transport layer, and a light emitting layer were formed on an insulating substrate by the same method as in Example 3. The layer thickness of the hole transport layer was 65 nm. The scratch hardness of the hole transport layer was H.

  Next, the light emitting layer was cured by heating and drying the insulating substrate on which the light emitting layer was formed at 200 ° C. for 1 hour in a nitrogen atmosphere. The scratch hardness of the light emitting layer after the heat treatment was 2H.

  Further, a second light emitting layer was formed by forming a blue light emitting polyfluorene-based material dissolved in xylene on the insulating substrate on which the light emitting layer was formed by spin coating.

  Next, the insulating substrate on which the light emitting second layer was formed was heated at 150 ° C. for 1 hour in a nitrogen atmosphere. The scratch hardness of the light emitting second layer after the heat treatment was H.

  Next, the insulating substrate on which the second electrode is formed is sealed with glass so as to cover the first electrode, the organic laminate including the hole transport layer, the light emitting layer, and the light emitting second layer, and the second electrode. An organic EL display device was prepared by sealing with a cap, and the luminance half time from a predetermined luminance was measured.

  Table 2 shows the luminance half time from the predetermined luminance of the organic EL display device according to Example 4.

  (Example 5) First, a first electrode and a hole transport layer were formed on an insulating substrate by the same method as in Example 1. The layer thickness of the hole transport layer was 65 nm. The scratch hardness of the hole transport layer was H.

  Next, a light emitting layer is formed by forming a xylene solution containing a green light emitting polyfluorene-based material and 25% by weight of a thermosetting hole transporting material on the insulating substrate on which the hole transporting layer is formed by spin coating. Formed.

  Next, the light emitting layer was cured by heating and drying the insulating substrate on which the light emitting layer was formed at 150 ° C. for 1 hour in a nitrogen atmosphere. The scratch hardness of the light emitting layer after the heat treatment was 2H.

  Next, the second electrode was formed by the same method as in Example 3, and the organic EL display device was created by sealing with a sealing cap, and the luminance half time from a predetermined luminance was measured.

  Table 2 shows the luminance half time from the predetermined luminance of the organic EL display device according to Example 5.

  (Example 6) A first electrode was formed on an insulating substrate in the same manner as in Example 1.

  On the insulating substrate on which the first electrode is formed, 3,4-polyethylenedioxythiophene / polystyrene sulfonate (PEDOT / PSS) is formed by spin coating, and heated at 210 ° C. for 10 minutes to thereby transport holes first. A layer was formed.

  Next, a thermally crosslinkable hole transport polymer is formed into a film with a thickness of 20 nm on the insulating substrate on which the hole transport layer is formed, and heated at 200 ° C. for 1 hour to form a hole transport second layer. A hole transport layer composed of a first layer and a hole transport second layer was formed.

  Next, a light emitting layer was formed by the same method as in Example 3.

  Next, the insulating substrate on which the light emitting layer was formed was heat-dried at 150 ° C. for 1 hour in a nitrogen atmosphere to form a crosslinked structure in the light emitting layer, and the light emitting layer was cured. The scratch hardness of the light emitting layer after the heat treatment was H.

  Next, the second electrode was formed by the same method as in Example 3, and the organic EL display device was created by satire with a sealing cap, and the luminance half time from a predetermined luminance was measured.

  Table 2 shows the luminance half time from the predetermined luminance of the organic EL display device according to Example 6.

  Comparative Example 1 A first electrode, a hole transport layer, and a light emitting layer were formed on an insulating substrate by the same method as in Example 1. The layer thickness of the hole transport layer was 65 nm. The scratch hardness of the hole transport layer was H.

  The insulating substrate on which the light emitting layer was formed was left at room temperature (25 ° C.) for 1 hour in a nitrogen atmosphere. Further, the scratch hardness of the light emitting layer after standing for 1 hour was H.

  Next, a second electrode was formed by the same method as in Example 1, and an organic EL display device was created by sealing with a sealing cap, and the luminance half time from a predetermined luminance was measured.

  Table 1 shows the luminance half time from the predetermined luminance of the organic EL display device according to Comparative Example 1.

  Comparative Example 2 A first electrode, a hole transport layer, and a light emitting layer were formed on an insulating substrate by the same method as in Example 1. The layer thickness of the hole transport layer was 65 nm. The scratch hardness of the hole transport layer was H.

  The insulating substrate on which the light emitting layer was formed was left at 90 ° C. for 1 hour. Further, the scratch hardness of the light emitting layer was H.

  Next, a second electrode was formed by the same method as in Example 1, and an organic EL display device was created by sealing with a sealing cap, and the luminance half time from a predetermined luminance was measured.

  Table 1 shows the luminance half time from the predetermined luminance of the organic EL display device according to Comparative Example 2.

  (Comparative Example 3) An organic EL display device was prepared by the same method as in Example 3 except that the insulating substrate on which the light emitting layer was formed was heated at 150 ° C for 1 hour in a nitrogen atmosphere, and the luminance half time from a predetermined luminance was obtained. Was measured.

  The layer thickness of the hole transport layer was 65 nm. The scratch hardness of the hole transport layer was H.

  Further, the scratch hardness of the light emitting layer after the heat treatment was H.

  Table 2 shows the luminance half time from the predetermined luminance of the organic EL display device according to Comparative Example 3.

表１は、実施例１〜２、及び比較例１〜２のそれぞれの輝度半減時間を示す表である。

Table 1 is a table | surface which shows each brightness | luminance half-life of Examples 1-2 and Comparative Examples 1-2.

In Examples 1 and 2 and Comparative Examples 1 and 2 using a blue light emitting polyolefin-based material as the light emitting material shown in Table 1, the predetermined luminance was set to 1000 cd / m ² .

  In Table 1, the value described in the column of “Luminance half time (normalization)” is a value obtained by normalizing each luminance half time based on the luminance half time of Comparative Example 1. .

  As shown in Table 1, in Example 1 and Example 2 in which the scratch hardness of the light emitting layer is 2H or more, the luminance half-life is 100 hours or more, which is three times that in Comparative Example 1 in which the scratch hardness of the light emitting layer is H. The above values were shown. This is because the scratching hardness of the light emitting layer is as high as 2H or more, so that the light emitting layer and the hole transport layer, and the light emitting layer and the second electrode are prevented from intermingling, thereby reducing the light emitting efficiency of the organic layer. This is because the time required is long. Therefore, it can be seen that an organic EL display device having a light emitting layer scratch hardness of 2H or more has a long luminance half-life and a long product life.

  Further, Comparative Example 2 exhibited a short luminance half-life despite the light emitting layer being heated and dried. From this, it can be seen that the luminance half-life does not directly correlate with the drying temperature of the light emitting layer, but directly correlates with the scratch hardness of the light emitting layer.

  Further, from the results shown in Table 1, it can be seen that Example 2 in which the light emitting layer has a scratch hardness of 3H has a longer luminance half time than Example 1 in which the light emitting layer has a scratch hardness of 2H. Accordingly, by increasing the scratch hardness of the light emitting layer, the crossing between the light emitting layer and the layer in contact with the light emitting layer is effectively suppressed, and the luminance half-life and product life of the organic EL display device are further increased. I can see that

表２は、実施例３〜６、及び比較例３のそれぞれの輝度半減時間を示す表である。

Table 2 is a table | surface which shows each brightness | luminance half time of Examples 3-6 and the comparative example 3. FIG.

In addition, about Examples 3-6 using the green light emission polyolefin-type material as a light emitting material shown in Table 1, and the comparative example 3, predetermined brightness was 2000 cd / m < ² >.

  In Table 2, the value described in the column of “Luminance Half Time (Normalization)” is a value obtained by normalizing each luminance half time based on the luminance half time of Comparative Example 3. .

  As shown in Table 2, Example 3 and Example 5 in which the scratch hardness of the light emitting layer is 2H or more have a long luminance half time of 600 hours or more, and Comparative Example 3 in which the scratch hardness of the light emitting layer is H. A value of 3 times or more of the luminance half-time of was shown. This is because the scratching hardness of the light emitting layer is as high as 2H or higher, so that the light emitting layer and the hole transport layer, and the light emitting layer and the second electrode are prevented from intermingling until the light emitting efficiency of the organic layer decreases. This is because the time required is long. Therefore, it can be seen that an organic EL display device having a light emitting layer scratch hardness of 2H or more has a long luminance half-life and a long product life.

  In addition, Example 3 in which the scratch hardness of the light emitting layer was improved by heating the light emitting layer, and Example in which the scratch hardness of the light emitting layer was improved by adding a thermosetting hole transport material to the light emitting layer and performing thermal crosslinking. 5 had a long luminance half time. From this, it can be seen that the luminance half-life is correlated with the scratch hardness of the light emitting layer, regardless of the means for improving the scratch hardness of the light emitting layer. That is, in the present invention, it is understood that the method for improving the scratch hardness of the organic layer is not limited at all.

  Further, as shown in Table 2, Comparative Example 3 is also applied to Example 4 in which the light emitting layer is formed in a two-layer structure of a light emitting first layer having a scratch hardness of 2H and a light emitting second layer having a scratch hardness of H. It has a very long luminance half time of 4.1 times. Accordingly, the scratch hardness of the entire light emitting layer is not necessarily 2H or more. If at least the first light emitting layer in contact with the hole transport layer has a scratch hardness of 2H or more, the light emitting layer and the hole transport layer are mixed. It can be seen that the matching can be suppressed and a long luminance half-life and product life can be realized.

  In addition, as shown in Table 2, Example 6 in which the hole transport layer has a scratch hardness of 2H has a luminance half time that is three times or more that of Comparative Example 3 in spite of the light emitting layer having a scratch hardness of H. Have. From this, it is not always necessary that the light emitting layer has a scratch hardness of 2H or higher, and even when the organic layer in contact with the light emitting layer has a scratch hardness of 2H or higher, a long luminance half-life and product life can be realized. I understand.

  In Examples 1 to 6, the light emitting layer includes a light emitting polyolefin-based material that is an organic polymer material, and the hole transport layer includes PEDOT / PSS that is an organic polymer material. It could be formed easily and inexpensively by a certain spin coating method.

  In addition, since the light emitting layer and the hole transport layer contain an organic polymer material as described above, the light emitting layer and the hole transport layer are not crystallized by performing a treatment such as heat treatment to improve the scratch hardness of the organic layer. A wide range of curing conditions can be selected in the organic layer effect step.

1 is a cross-sectional view of an organic EL display device 100 according to the present invention. It is sectional drawing of the conventional organic electroluminescent display apparatus 200. FIG. It is a schematic sectional drawing which shows the organic laminated body 230 part of the organic EL display apparatus 200 of the state which is not supplying with electricity. It is a schematic sectional drawing which shows the organic laminated body 230 'part of the organic electroluminescent display apparatus 200' in the state by which the crossing layers 232a 'and 232c' were formed by supplying with electricity.

Explanation of symbols

100, 200, 200 ′ Organic EL display device 110, 210 Substrate 120, 220 First electrode 130, 230, 230 ′ Organic laminated body 131, 231, 231 ′ Hole transport layer 132, 232, 232 ′ Light emitting layer 140, 240 First 2 electrodes 232a ′, 232c ′ crossing layer 232b main light emitting layer 233, 233 ′ electron transport layer

Claims (3)

A substrate,
A first electrode provided on the substrate;
An organic laminate including a light emitting layer and an organic layer laminated so as to be in contact with the light emitting layer, provided on the first electrode;
A second electrode provided on the organic laminate,
An organic electroluminescence display device comprising:
The said light emitting layer and / or the said organic layer are organic electroluminescent display apparatuses whose scratch hardness defined by JISK5600-5-4 is 2H or more. The organic electroluminescence display device according to claim 1,
The light emitting layer and / or the organic layer is an organic electroluminescence display device containing an organic polymer compound. An organic laminate including a substrate, a first electrode provided on the substrate, a light emitting layer provided on the first electrode and an organic layer laminated to be in contact with the light emitting layer, and the organic laminate A method of manufacturing an organic electroluminescence display device comprising: a second electrode provided on a body,
An organic laminate forming step of forming the organic laminate including the light emitting layer and the organic layer on the first electrode provided on the substrate,
The organic laminate forming step includes a curing step of curing the light emitting layer and / or the organic layer.

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