JP2008078038A - Organic el display panel and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL display panel with little brightness unevenness by adoption of an auxiliary wiring structure with small man-hour increase. <P>SOLUTION: Of a top-face emission type display panel with an organic EL substrate and a color filter substrate bonded together, the organic EL substrate has a transparent substrate, a TFT+flattened resin layer, a reflective electrode layer, an organic EL layer and a transparent electrode laminated in that order, the reflective electrode layer consists of a reflective electrode, an auxiliary wiring, and an insulating film with openings at a position corresponding to a light-emitting part on the reflective electrode and on the auxiliary wiring. The auxiliary wiring is provided so as to be connected from one end of a screen to the other, has a shadow mask with a reverse tapered cross section so as its bottom face to be in contact with the auxiliary wiring inside the opening, the organic EL layer on the reflective electrode layer is formed so as to cover the reflective electrode fitted inside the opening at a position corresponding to the light-emitting part of the insulating film, and the transparent electrode covers the organic EL film formed so as to cover the reflective electrode and the insulating film in its periphery to be connected with the auxiliary wiring. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an organic EL display panel, and more particularly to an organic EL display panel having a top emission structure and a manufacturing method thereof.

  A panel unit of an organic EL display having a top emission structure generally has a configuration in which an organic EL substrate (TFT substrate) 11 and a color filter substrate 12 are bonded together as shown in FIG.

  Regarding the pixel portion of this panel, a conventional organic EL display having a structure as shown in FIG. 2 is used. FIG. 2A is a plan view showing the pixel portion, FIG. 2B left side is an AB cross-sectional view, and FIG. 2B right side is a CD cross-sectional view. First, a flattening resin 20 that wraps the TFT and flattens the whole is provided on the glass substrate. The planarizing resin 20 may be covered with an inorganic passivation film as necessary. A reflective electrode 22 is formed on the planarizing resin 20 or the passivation film via a base layer 21 that improves adhesion. An insulating film 23 having an opening in the light emitting portion is formed thereon, and an organic EL layer 24 is formed thereon. The organic EL layer is an organic light emitting layer, or a layer formed by combining one or more of this with, for example, an electron injection layer, an electron transport layer, a hole transport layer, or a hole injection layer. It is formed by. A transparent electrode layer 25 is provided on the organic EL layer. The transparent electrode layer 25 can be formed by sputtering, for example. The transparent electrode 25 is connected to the wiring at the outer periphery of the panel. Finally, the entire pixel portion is covered with the barrier layer 26.

On the other hand, on the color filter substrate side, a black matrix 27, a color filter 28, and a color conversion layer 29 are formed on a glass substrate. Of course, there is a method that does not use a color conversion layer.
The organic EL substrate 11 and the color filter substrate 12 are positioned and bonded so that the pixels are aligned. The gap layer fills the gap between the organic EL substrate 11 and the color filter substrate 12, and generally a solid such as an adhesive is used, but it may be a liquid or a gas. When it is desired to precisely control the gap between the organic EL substrate 11 and the color filter substrate 12, a spacer may be provided on the color filter 28 or the color conversion layer 29. If the gap is too wide, there will be a problem of crosstalk in which light enters the adjacent pixels. If it is too narrow, the influence of interference or mechanical contact with the light emitting region may occur.

In the top emission structure as shown in FIG. 2, the transparent electrode layer 25 is made of a material having a higher resistivity than metals such as IZO and ITO, and is thin so as not to damage the organic EL layer. Therefore, the wiring resistance is large, and a potential difference may occur between the center and the periphery of the screen, resulting in display unevenness. This becomes more conspicuous as the screen becomes larger. On the other hand, there is an attempt to reduce resistance by forming a metal auxiliary wiring (see, for example, Patent Document 1).
However, in this method, the transparent electrode and the auxiliary wiring cannot be electrically connected unless the organic film is hidden by the metal mask. Therefore, high definition is difficult and the cost of the mask alignment mechanism and the mask itself increases.

  Therefore, a method has been developed in which the organic layer is divided using the metal auxiliary wiring itself without using a high-definition metal mask, and only the transparent electrode is connected to the metal auxiliary wiring (for example, see Patent Document 2). This is because the vapor deposition is relatively directional, and in the sputtering, the difference in the phenomenon that the particles wrap around the shadow portion is used.

  In addition, a plurality of transparent electrodes arranged in stripes on a transparent substrate, a plurality of parallel barrier ribs extending in a direction intersecting the transparent electrodes, and a region of the transparent electrode exposed without being covered by the barrier ribs are formed. The partition has an overhang portion protruding in parallel to the transparent substrate, and the partition is formed on an insulating film formed at least including a partition formation region on the transparent substrate. There is also a proposal of an organic EL display panel which is formed and an auxiliary conductive line is formed at a base portion of the insulating film-shaped partition wall extending along a cautious direction of the partition wall (see, for example, Patent Document 3). The auxiliary conductive line is electrically coupled to the reflective electrode, and attempts to reduce the voltage drop between the reflective electrode and the transparent electrode located far from the current source.

JP 2003-288994 A JP, 2005-93398, A FIG. 1, FIG. JP 2000-331784 A

  However, in the sputtering in Patent Document 2, it goes without saying that the metal auxiliary wiring must be made sufficiently thicker than the film thickness of the organic layer in order to use the difference in the phenomenon that the particles go into the shadow part. . However, in the case of FIG. 1 of Patent Document 2, since the auxiliary wiring is formed at the same time as the reflective electrode, if this is thickened, the reflective electrode itself becomes thick and the surface irregularities are enlarged, causing leakage. However, problems such as difficulty in forming an insulating film arise.

On the other hand, when the thick auxiliary wiring is formed on the insulating film with the configuration as shown in FIG. 11 of Patent Document 2, a residue when the metal is patterned remains on the reflective electrode, causing leakage or being attached first. The metal reflective electrode is slightly etched, leading to a decrease in reflectivity, that is, a decrease in luminance, and a risk of leakage due to an increase in unevenness. Furthermore, in this configuration, a process of metal film formation → resist application / exposure → metal etching is required only for the auxiliary wiring, which increases costs.
Further, in Patent Document 2, since the connection position of the transparent electrode is on the side surface of the auxiliary wiring, the substantial connection width is limited to about several tens to several hundreds nm, and there is a problem that it is difficult to secure a sufficient connection area.

  Further, the organic EL display panel of Patent Document 3 has a bottom emission structure, and here, an organic EL layer formed after an auxiliary conductive line is formed on an insulating film and then a partition wall having an overhang portion is formed. A reflective electrode is formed on the substrate. That is, in manufacturing the organic EL display described in Patent Document 3, it is necessary to add an auxiliary conductive formation process to the conventional organic EL display manufacturing process. As in the case of FIG. ⇒Resist application / exposure ⇒Metal etching is required, which increases costs.

  Therefore, an object of the present invention is to realize a structure that suppresses the influence and damage to the reflective electrode such as leakage and a decrease in reflectance and realizes a structure with a small increase in man-hours, and thus has little luminance unevenness when adopting the auxiliary wiring structure. It is to provide a display panel at a low cost.

  The organic EL display panel of the present invention is an organic EL display panel having a top emission structure in which an organic EL substrate and a color filter substrate are bonded to each other. The organic EL substrate is a transparent substrate and a TFT + flattened thereon. A resin layer, a reflective electrode layer formed on the TFT + flattened resin layer, an organic EL layer formed thereon, and a transparent electrode formed on the organic EL layer, The reflective electrode layer includes a reflective electrode, an auxiliary wiring, a position corresponding to the light emitting portion on the reflective electrode, and an insulating film having an opening on the auxiliary wiring, and the auxiliary wiring extends from one end of the screen to the other end. A shadow mask having a reverse tapered cross section is provided so as to extend along the auxiliary wiring so that the bottom surface is in contact with the auxiliary wiring in the opening. The organic EL layer provided on the electrode layer is formed so as to cover the reflective electrode provided in the opening corresponding to the light emitting portion of the insulating film and the surrounding insulating film, and the transparent electrode is formed by reflecting the reflective electrode. The organic EL film formed so as to cover the electrode and the surrounding insulating film is covered, and the space between the shadow mask and the organic EL layer is filled to connect to the auxiliary wiring.

  The organic EL display panel manufacturing method of the present invention includes a TFT + flattened resin layer forming step of forming a TFT + flattened resin layer on a transparent substrate, and a screen between sub-pixels on the TFT + flattened resin layer. A reflective electrode forming step for simultaneously forming the auxiliary wiring and the reflective electrode connected from one end of the electrode to the other end, an opening corresponding to the light emitting portion on the reflective electrode, and an opening on the auxiliary wiring as well An insulating film forming step of forming an insulating film layer having a reverse taper-shaped cross section extending along the auxiliary wiring so that a bottom surface of the insulating film is in contact with the auxiliary wiring in the opening provided on the auxiliary wiring A shadow mask forming step of providing a shadow mask, and an organic EL layer is formed so as to cover the reflective electrode provided in the opening at a position corresponding to the light emitting portion of the insulating film and the surrounding insulating film. Connect to the auxiliary wiring by covering the organic EL film formed so as to cover the reflective electrode and the surrounding insulating film, and filling the space between the shadow mask and the organic EL layer. And a transparent electrode forming step.

  In the manufacturing method of the organic EL display panel of the present invention, the auxiliary wiring is formed simultaneously with the reflective electrode, so that the manufacturing process of only the auxiliary wiring is unnecessary. Moreover, since the organic EL layer can be reliably divided by the organic shadow mask, it is not necessary to make the auxiliary wiring = the reflective electrode thick. Furthermore, since an organic shadow mask is used, only the steps of resist coating and exposure are increased. Alternatively, when it is necessary to use a spacer from the beginning, this can be used as a spacer, so that the total man-hour is not increased. In addition, the organic EL display of the present invention has a small voltage drop between the reflective electrode and the transparent electrode as it is away from the power source, and also has a problem that the unevenness becomes large when the reflective electrode is thick, and a cost increase due to an increase in the manufacturing process. It has the feature of not.

First, the organic EL display panel of the present invention will be described.
FIG. 3 shows a first embodiment of the organic EL display panel of the present invention. 3A is a plan view of the pixel portion, and FIG. 3B is a cross-sectional view taken along AB. The structure shown in FIG. 3 is one in which auxiliary electrodes are arranged between the sub-pixels and wired in the long side direction of the sub-pixel, and importance is placed on reducing the wiring resistance.

  On the transparent substrate, a TFT (thin film transistor) and a flattening resin 20 that wraps the TFT and flattens the whole are provided. The planarizing resin 20 may be covered with an inorganic passivation film as necessary. A reflective electrode 22 is formed on the planarizing resin 20 or the passivation film via a reflective electrode base layer 21 that improves the adhesion of the reflective electrode 22. As the transparent substrate, TFT, and planarizing resin, any of those usually used for the transparent substrate, TFT, and planarizing resin of an organic display panel can be used. The wiring from the TFT to each pixel is installed through a contact hole provided in the planarizing resin. Any inorganic passivation film that can be used in an organic display panel can be used, and examples thereof include a single layer or a laminate of SiO2, SiN, SiON, and the like.

The reflective electrode base layer 21 is a layer provided to ensure adhesion of the reflective electrode 22 to the planarization layer 20 or the inorganic passivation layer, and an oxide such as ITO or IZO is used. An auxiliary wiring 32 is also provided on the planarizing resin 20 or the passivation film via an auxiliary wiring base layer 31. The auxiliary wiring base layer 31 is also a layer provided to ensure adhesion of the auxiliary wiring 32 to the planarization layer 20 or the inorganic passivation layer, and an oxide such as ITO or IZO is used. A reflective electrode 22 made of, for example, MoCr, CrB, Ag, or an Ag alloy is formed on the reflective electrode base layer 21. An auxiliary wiring 32 made of the same material is also formed on the auxiliary wiring base layer 31.
The reflective electrode 22 is provided in the opening of the insulating film at a position corresponding to the light emitting portion, and the auxiliary wiring 32 is the opening of the insulating portion in a portion (auxiliary wiring forming position) between the light emitting portion and the adjacent light emitting portion. Provided in the section. The auxiliary wiring is provided so as to be connected from one end of the screen (display screen of the organic EL display) to the other end.

  On the planarization resin 20 or the passivation film on which the reflective electrode 22 and the auxiliary wiring 32 are provided, an insulating film layer having an opening in the light emitting portion is provided. This light emitting portion is a portion at a position corresponding to a pixel or a sub pixel of the organic EL display panel, and is a portion that emits light when a potential difference is generated between the reflective electrode and the transparent electrode facing each other across the organic EL layer.

  A shadow mask 33 having a reverse tapered cross section is provided so as to extend along the auxiliary wiring 32 so that the bottom surface of the auxiliary wiring 32 is in contact with the auxiliary wiring 32 in the opening. In the example shown in FIG. 3, the shadow mask 33 is provided so that its bottom surface is located at the center in the width direction of the auxiliary wiring, and is connected from one end of the screen to the other end in the longitudinal direction of the auxiliary wiring. It is provided as follows.

The organic EL layer is formed so as to cover the reflective electrode provided in the opening corresponding to the light emitting portion of the insulating film and the insulating film around it. The organic EL layer includes at least an organic light emitting layer, and contains a hole injection layer, a hole transport layer, an electron transport layer and / or an electron injection layer as necessary.
That is, the organic EL layer may consist of only (A) the organic light emitting layer, and from the transparent electrode side,
(B) Hole injection layer / organic light emitting layer (C) organic light emitting layer / electron transport layer (D) hole injection layer / organic light emitting layer / electron transport layer (E) hole injection layer / hole transport layer / organic The light emitting layer / electron transport layer (F) hole injection layer / hole transport layer / organic light emitting layer / electron transport layer / electron injection layer may be employed.

  As shown in FIG. 3, due to the reverse tapered cross-sectional shape of the shadow mask 33, the organic EL layer formed on the shadow mask and the organic EL layer formed on the reflective electrode and the surrounding insulating film are separated. . That is, the organic EL layer 24 is divided for each subpixel column by the shadow mask 33 as shown in FIG. 3A, and the auxiliary wiring remains exposed at the base of the shadow mask.

  A transparent electrode is formed on the organic EL layer formed on the reflective electrode and the surrounding insulating film, and the transparent electrode is formed so as to cover the reflective electrode and the surrounding insulating film. The EL film is covered and the space between the shadow mask and the organic EL layer is filled to connect to the auxiliary wiring. That is, the space separating the organic EL layer formed on the shadow mask and the reflective electrode and the organic EL layer formed on the surrounding insulating film, and the space between the insulating film connected to the space and the shadow mask side wall The transparent electrode is connected to the auxiliary wiring exposed between the insulating film and the side wall of the shadow mask. Since the connection between the transparent electrode and the auxiliary wiring is connected to the upper surface instead of the side surface of the auxiliary wiring as in Patent Document 2, the connection width can be several μm and a sufficient connection area can be secured.

  Between the transparent electrode and the organic EL layer, a highly transparent metal such as Mg, Ag, or Au may be formed on the order of several to 10 nm in order to reduce damage given to the organic EL film when the transparent electrode is formed. .

An inorganic barrier layer 26 is formed so as to cover the transparent electrode thus formed over the entire screen. The inorganic barrier layer, SiO ₂ or SiN, one made of a single layer or a laminate such as SiON can be exemplified.

  On the other hand, the color filter substrate is formed by laminating a black matrix 27, a color filter 28, and, if necessary, a color conversion layer 29 on a transparent substrate. The organic EL substrate and the color filter substrate are bonded by an adhesive, and the gap layer is filled with a solid or a liquid or a gas as necessary.

  FIG. 4 shows a second embodiment of the organic EL display panel of the present invention. 4A is a plan view showing the pixel portion, and FIG. 4B is a CD cross-sectional view. In the structure shown in FIG. 4, auxiliary wiring is arranged between pixels (one pixel for RGB sub-pixels) and wired in the short-side direction of the sub-pixel, and the effective area of the pixel is the first mode. It is a larger one.

  FIG. 5 shows a third embodiment of the organic EL display panel of the present invention. FIG. 5A is a plan view showing the pixel portion, and FIG. 5B is a CD cross-sectional view. In the structure shown in FIG. 5, the auxiliary electrode is arranged between the pixels and wired in the short side direction of the subpixel so that the auxiliary wiring and the transparent electrode can be contacted only on one side near the bottom surface of the shadow mask 53. Is. This is a structure in which the effective area of the pixel can be further expanded as compared with the second mode by making the auxiliary wiring thinner. However, if the auxiliary wiring is made thinner, the contact resistance and the resistance of the auxiliary wiring increase accordingly. At this time, it is preferable that the shadow mask is installed in the cross section of FIG. 5CD so that the upper left end of the shadow mask extends to the pixel opening of the insulating film and the lower right end of the shadow mask extends to a position where the insulating film auxiliary wiring opening is not filled. Although FIG. 5 shows a structure in which the bottom surface of the shadow mask is on both the insulating film and the opening wiring, a structure in which the bottom surface is on the insulating film and the opening is only on one side of the shadow mask may be used. However, in this case, it is necessary to consider that the process rule for making the opening is strict and a very narrow hole cannot be formed.

  FIG. 6 shows a fourth embodiment of the organic EL display panel of the present invention. FIG. 6A is a plan view showing the pixel portion, and FIG. 6B is a CD cross-sectional view. The structure shown in FIG. 6 is characterized in that auxiliary wiring is arranged between pixels and wired in the short side direction of the subpixel, but the shadow mask 63 is cut off halfway. For example, if the auxiliary wiring is thinned, the probability that a portion that cannot be connected to the transparent electrode or a portion where the contact resistance is increased is increased. Is connected to the entire screen in a plane shape, so that the wiring resistance becomes uniform. In addition, in this structure, when the gap layer is filled with a material having a high viscosity such as an adhesive, the barrier layer is small, so that it easily spreads cleanly on the entire surface. In addition, when the filler is injected into the gap layer, the filler easily spreads from the dripped state, and the filler can be easily injected into the gap layer.

The first to fourth embodiments may be used alone or in combination. For example, a structure in which the auxiliary wiring is formed in the long-side direction and the short-side direction (that is, in a lattice shape) of the subpixel and a shadow mask is partially placed thereon is also within the scope of the present invention.
The metal auxiliary wiring preferably has a structure that extends to the outer periphery of the screen and directly connects to the wiring to the outside. However, a structure in which the metal auxiliary wiring is cut off halfway and connected to the wiring to the outside via the transparent electrode may be used. In the present invention, the structure is not limited to the first to fourth embodiments.

Next, the manufacturing method of the organic EL display of the present invention will be described.
TFT + planarizing resin layer forming process:
First, a TFT is formed on a transparent substrate, and a photocurable resin is applied and exposed in order to flatten the TFT. At this time, wiring from the TFT of each pixel is dealt with by providing a contact hole (opening) in the resin. Further, in order to prevent outgas from the resin, a single-layer or laminated inorganic passivation film such as SiO ₂ , SiN, or SiON may be provided thereon by chemical vapor deposition (CVD) or the like.

Reflective electrode formation process:
Next, an underlayer 21 of an oxide such as IZO or ITO is formed by a photo process in order to ensure adhesion. At that time, the base layer 31 of the auxiliary wiring is simultaneously formed with the same material. On this, a reflective electrode 22 such as MoCr, CrB, Ag, or an Ag alloy is formed. Similarly, at this time, the auxiliary wiring 32 is simultaneously formed of the same material. When forming the reflective electrode, these alloys also enter the contact hole, and the reflective electrode and the TFT are connected.

Insulating film formation process:
Then, SiO ₂ , SiN, SiON or the like is formed by CVD or the like, and after the photo process, dry etching is performed to form an insulating film 23 having an opening. Needless to say, an organic insulating film that can be formed only by the photolithography method may be formed instead of the inorganic insulating film. The insulating film opening is formed on the light emitting portion of the pixel and the auxiliary wiring.

Shadow mask formation process:
Next, a photosensitive resist material is applied and the exposure amount is adjusted, so that the bottom surface of the insulating film provided on the auxiliary wiring extends along the auxiliary wiring so that the bottom surface is in contact with the auxiliary wiring. A shadow mask 33 having a reverse tapered cross section is formed.

Organic EL layer forming step:
This is put into a vapor deposition apparatus, and the organic EL layer 24 is formed. The organic EL layer includes at least an organic light-emitting layer, and contains a hole injection layer, a hole transport layer, an electron transport layer and / or an electron injection layer as necessary, all of which are formed by vapor deposition under reduced pressure. It is formed. These layers are preferably formed continuously without returning the reduced pressure to the normal pressure.
In addition, a metal having high transmittance such as MgAg or Au may be deposited on the order of several nm to 10 nm in order to alleviate damage during sputtering of the transparent electrode. At this time, the organic EL layer (+ deposited metal) is divided for each subpixel column by the shadow mask 33, and the auxiliary wiring remains exposed at the base of the shadow mask.

Transparent electrode formation process:
Next, a transparent electrode such as IZO or ITO is formed into a sputtering apparatus. In the sputtering apparatus, since the particles also move to the shadowed part, the transparent electrode material is formed as far as the shadow mask and is connected to the auxiliary wiring.

Barrier layer formation process:
Next, by using a CVD apparatus or the like, at least the entire screen is covered with a single or laminated inorganic barrier layer 26 such as SiO ₂ , SiN, or SiON.

  On the other hand, the color filter substrate is formed by photolithography in the order of the black matrix 27, the color filter 28, and, if necessary, the color conversion layer 29 on the glass. The organic EL substrate and the color filter substrate are bonded by an adhesive, and the gap layer is filled with a solid or a liquid or a gas as necessary.

  If the auxiliary wiring is wired in the long-side direction of the subpixel in the reflective electrode forming step, and the shadow mask is provided in the shadow mask forming step so that the bottom surface of the shadow mask is located in the center in the width direction of the auxiliary wiring, FIG. The first embodiment of the organic EL display panel of the present invention as shown in FIG. 1, and auxiliary wiring is wired between pixels (one pixel in RGB subpixels) and between the pixels and in the short side direction of the subpixels. If the shadow mask is provided on the top so that the bottom surface is positioned at the center of the auxiliary wiring in the width direction, the second embodiment of the organic EL display panel of the present invention as shown in FIG. If the position of the bottom face of the shadow mask is set so that the auxiliary wiring and the transparent electrode can be contacted only on one side, the organic EL display of the present invention as shown in FIG. To a third embodiment of Ipaneru. The auxiliary wiring is arranged between the pixels and wired in the short side direction of the sub-pixel. However, if the shadow mask 63 is installed so as to be cut off halfway, the organic of the present invention as shown in FIG. It becomes the 4th form of EL display panel.

The present invention will be further described below with reference to examples.
<Example 1>
A TFT for a plurality of screens is formed on an alkali-free glass of 200 × 200 mm × 0.7 mm thick, and a passivation composed of a 3 μm thick planarizing resin and 300 nm thick SiO ₂ is formed so as to cover the TFT. An IZO film with a thickness of 50 nm was formed on the substrate. The sputtering apparatus used was an RF-planar magnetron and the gas used was Ar. After applying a resist agent “OFRP-800” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) to this, exposure and development were performed, and the reflective electrode base layer pattern 21 separated into islands for each subpixel was formed by wet etching. This pattern is connected to the TFT through a contact hole provided in the planarization layer and the passivation layer. Further, between the sub-pixels, a linear pattern (auxiliary wiring base layer) 31 extending from end to end of the screen in the long-side direction of the sub-pixels was formed simultaneously.

A reflective electrode 22 and an auxiliary wiring 32 were simultaneously formed by the same process so that Ag was sputtered to 200 nm on these patterns so as not to protrude from the underlying patterns 21 and 31.
Next, a 300 nm SiN film is formed by a CVD apparatus, a resist agent is applied, a resist opening is formed on the light emitting portion, the auxiliary wiring, the panel terminal portion, and the like using a photolithographic method, and this is dry etched. An opening was formed in SiN, and an insulating film 23 having an opening at a predetermined position was formed.

  Next, a shadow mask 33 was formed by photolithography on the insulating film opening on the auxiliary wiring. The shadow mask 33 is a novolac resist material (Nippon ZEON ZNP1168), and the exposure time is adjusted so that the top surface has a width of about 12 μm, the bottom surface has a width of about 6 μm, and the height is about 4 μm. Further, the bottom surface of the shadow mask is located at the center of the auxiliary wiring, and is continuously provided on the auxiliary wiring from one end of the screen to the other end.

Next, it was mounted in a resistance heating vapor deposition apparatus, and Li of 1.5 nm was deposited on the reflective electrode to obtain a cathode buffer layer. Then, an electron transport layer, a light emitting layer, a hole transport layer, and a hole injection layer were formed in this order without breaking the vacuum to obtain an organic EL layer. During film formation, the internal pressure of the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa. Each layer is deposited at a deposition rate of 0.1 nm / s, tris (8-hydroxyquinolinato) aluminum (Alq3) having a thickness of 20 nm as an electron transport layer, and 4,4′-bis having a thickness of 30 nm as a light emitting layer. (2,2′-diphenylvinyl) biphenyl (DPVBi), 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD) having a thickness of 10 nm as a hole transport layer, As the hole injection layer, copper phthalocyanine (CuPc) having a thickness of 100 nm was used. Further, 5 nm of MgAg was vapor-deposited thereon to form a damage mitigating layer when the transparent electrode was formed by sputtering. The organic EL layer is divided into a layer formed on a part of the reflective electrode of the light emitting part and the surrounding insulating film and a layer formed on the shadow mask, whereby the organic EL layer on the light emitting part is sub-pixels. It was divided every row. Further, the auxiliary wiring is not covered with the organic EL layer at the base of the shadow mask, and is left exposed.

This was moved to the facing sputtering apparatus without breaking the vacuum, and IZO as the transparent electrode 25 was formed to a thickness of 100 nm. In these vapor deposition and sputter film formation, a metal mask having a square window at a position corresponding to the display portion was applied. By IZO sputtering, IZO was deposited up to the base of the shadow mask, and the transparent electrode (IZO) was connected to the auxiliary wiring.
Further, the substrate was moved to a CVD apparatus without breaking the vacuum, and SiN as a barrier layer 26 was formed on the entire surface of the transparent electrode with a thickness of 2 μm.

  On the other hand, on the color filter substrate side, first, a black matrix 27 (CK-7001: manufactured by Fuji Film ARCH) having a thickness of 1 μm was formed on a non-alkali glass having a size of 200 × 200 mm × 0.7 mm in thickness by a photolithographic method. Next, the color filters 28 are formed in red (CR-7001: manufactured by Fuji Film ARCH), green (CG-7001: manufactured by Fuji Film ARCH), and blue (CB-7001: manufactured by Fuji Film ARCH) by a photolithographic method. did. Each of them has a strip shape with a thickness of about 2 μm. Next, a color conversion layer 29 having a thickness of about 10 μm was formed using the same photomask as the color filter. The coating solution is 0.05 g of coumarin 6 for conversion to green, and 0.05 g of rhodamine B + coumarin 6 for conversion to red, with respect to 25 g of photoresist V259PAP5 (manufactured by Nippon Steel Chemical). Was added. In addition, since the emission spectrum of the organic EL element described above is blue to green (400 nm to 550 nm), blue was not formed as a color conversion layer but was formed of a transparent acrylic resin.

  Next, the organic EL substrate and the color filter substrate were moved to a bonding apparatus having oxygen of 5 ppm and moisture of 5 ppm or less. Then, set the color filter substrate process surface facing up, and apply the epoxy UV curing adhesive to each outer periphery (position 13 in FIG. 1) of each of the plurality of screens using a dispenser, so that a so-called bank is applied. Then, a low-viscosity thermosetting epoxy adhesive was dropped near the center of each screen. The dripping amount was the volume of the gap layer formed when the color filter substrate was brought close to the upper surface of the shadow mask. Then, set with the organic EL substrate process surface facing downward, with the color filter substrate and the process surface facing each other, depressurize to about 10 Pa, and then paste and align the pixel position. Returned to atmospheric pressure. As a result, the low-viscosity thermosetting epoxy adhesive spreads over the entire surface of the panel and approached to the point where the color conversion layer of the color filter substrate and the upper surface of the shadow mask of the organic EL substrate were in contact.

  Next, ultraviolet rays were irradiated only from the color filter substrate side to the outer peripheral adhesive portion (position 13 in FIG. 1) to be temporarily cured, and taken out to the general environment. Next, this was put in a heating furnace and heated at 80 ° C. for 1 hour, and then naturally cooled in the furnace for 30 minutes and taken out. This was divided into individual display panels as shown in FIG. 1 (however, there was no IC at this stage) by an automatic glass scribe device and an automatic break device. Finally, it was put into a dry etching apparatus, and the 2 μm thick barrier layer covering the terminal portion 15 and the IC connection pad was removed.

  The luminance unevenness (brightness difference between the center of the screen and the edge) of the obtained display panel can be reduced to about 1/10 compared to the case where there is no auxiliary wiring.

<Example 2>
An organic EL display panel having the form shown in FIG. 4 was obtained in the same manner as in Example 1 except that the pattern of the auxiliary wiring base layer was a linear pattern extending from the end of the screen in the short side direction of the subpixel.

<Example 3>
The pattern of the auxiliary wiring underlayer is a linear pattern extending from the edge of the screen to the short side of the subpixel, and the auxiliary wiring and transparent electrode can be contacted only on one side near the bottom of the shadow mask. 5 was obtained in the same manner as in Example 1 except that the position was set as shown in FIG.

<Example 4>
The pattern of the auxiliary wiring base layer is a linear pattern extending from the end of the screen in the short side direction of the sub-pixel, and the length of the shadow mask holding wiring in the longitudinal direction is about 1/3 of the pixel. An organic EL display panel having the form shown in FIG. 6 was obtained in the same manner as in Example 1 except that it was cut every time.

  In any of Examples 2 to 4, the luminance unevenness of the obtained display panel could be reduced to about 1/10 compared to the case where there was no auxiliary wiring.

  The top emission type organic display panel of the present invention can reduce the wiring resistance, and as a result, it becomes an organic EL display with little luminance unevenness even when the size is increased. In addition, according to the method for manufacturing a top emission type organic display panel of the present invention, an auxiliary wiring structure can be realized without incurring damage to the reflective electrode and an increase in the number of man-hours. It can be realized at low cost.

Overall view of top emission type organic EL display panel unit Schematic diagram showing the cross-sectional structure of a conventional top emission organic EL panel The schematic diagram which shows the 1st form of the organic electroluminescence display panel of this invention The schematic diagram which shows the 2nd form of the organic electroluminescent display panel of this invention The schematic diagram which shows the 3rd form of the organic electroluminescence display panel of this invention The schematic diagram which shows the 4th form of the organic electroluminescence display panel of this invention

Explanation of symbols

11: Organic EL substrate (including TFT if necessary)
12: Color filter substrate (including color conversion layer, if necessary)
13: Outer seal area 14: In-panel wiring 15: Terminal for FPC attachment 16: Control IC
20: TFT + flattened resin layer (an inorganic film is present on the surface if necessary)
21: Reflective electrode base layer 22: Reflective electrode layer 23: Insulating film 24: Organic EL layer 25: Transparent electrode 26: Barrier layer 27: Black matrix 28: Color filter 29: Color conversion layer 30: Spacer (rib)
31, 41, 51: Auxiliary wiring underlayers 32, 42, 52: Auxiliary wiring 33, 43: Shadow mask (located at the center of the auxiliary wiring and connected almost from end to end of the screen)
53: Shadow mask (biased on one side of the auxiliary wiring, almost connected from end to end of the screen)
63: Shadow mask (cut out in the screen. In this figure, smaller than the pixel)

Claims (8)

  In an organic EL display panel having a top emission structure in which an organic EL substrate and a color filter substrate are bonded together, the organic EL substrate includes a transparent substrate, a TFT + flattening resin layer provided thereon, and the TFT + flattening resin. A reflective electrode layer formed on the layer; an organic EL layer formed thereon; and a transparent electrode formed on the organic EL layer. The reflective electrode layer includes a reflective electrode and an auxiliary electrode. A wiring, a position corresponding to the light emitting portion on the reflective electrode, and an insulating film having an opening on the auxiliary wiring, and the auxiliary wiring is provided so as to be connected from one end of the screen to the other end. A shadow mask having a reverse tapered cross section is provided to extend along the auxiliary wiring so that the bottom surface of the auxiliary wiring is in contact with the auxiliary wiring, and the organic EL layer provided on the reflective electrode layer is The insulating film is formed so as to cover the reflective electrode provided in the opening corresponding to the light emitting portion and the surrounding insulating film, and the transparent electrode is formed so as to cover the reflective electrode and the surrounding insulating film. An organic EL display panel, wherein the organic EL display panel is connected to the auxiliary wiring by covering the organic EL film and filling a space between the shadow mask and the organic EL layer.   A bottom surface of the shadow mask having the reverse tapered cross section is disposed so as to be biased to one side of the insulating film opening on the auxiliary wiring, and a part of the bottom surface is disposed on the insulating film, and the transparent electrode is the shadow electrode. 2. The organic EL display panel according to claim 1, wherein the auxiliary wiring is connected to only one side of the mask.   3. The organic EL display panel according to claim 1, wherein the shadow mask having the reverse tapered cross section is provided so as to be connected from one end of the screen to the other end along the auxiliary wiring.   3. The organic EL display panel according to claim 1, wherein the shadow mask having an inversely tapered cross section is partially cut off or only partially present in the screen.   TFT + flattened resin layer forming step for forming TFT + flattened resin layer on a transparent substrate, and auxiliary wiring connected from one end of the screen to the other end between the subpixels on the TFT + flattened resin layer, A reflective electrode forming step of forming the reflective electrode at the same time, an insulating film forming step of forming an insulating film layer having an opening on the auxiliary wiring and having an opening in a portion corresponding to the light emitting portion on the reflective electrode; A shadow mask forming step of providing a shadow mask having a reverse tapered cross section extending along the auxiliary wiring so that a bottom surface thereof is in contact with the auxiliary wiring in the opening provided on the auxiliary wiring; and An organic EL layer forming step of forming an organic EL layer so as to cover the reflective electrode provided in the opening corresponding to the light emitting portion and the surrounding insulating film; and the reflective electrode and the surrounding insulating film An organic EL display panel comprising a transparent electrode forming step of covering the organic EL film formed to cover and connecting to the auxiliary wiring by filling a space between a shadow mask and the organic EL layer Manufacturing method.   The bottom surface of the shadow mask having the reverse tapered cross section is disposed so as to be biased to one side of the insulating film opening on the auxiliary wiring, and a part of the bottom surface is disposed on the insulating film, and the transparent electrode is the shadow mask. 6. The method of manufacturing an organic EL display panel according to claim 5, wherein the auxiliary wiring is connected only to one side of the organic EL display panel.   7. The organic EL display panel according to claim 5, wherein a shadow mask having a reverse tapered cross section is provided so as to be connected from one end of the screen to the other end along the auxiliary wiring. Production method.   7. The method of manufacturing an organic EL display panel according to claim 5, wherein the shadow mask having the reverse tapered cross section is partially cut off or only partially present in the screen.

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