JP2018106803A - Organic EL display device and method of manufacturing organic EL display device - Google Patents

Abstract

In an organic EL display device, leakage current between adjacent pixels is more reliably suppressed.
An organic EL display device includes a substrate, a lower electrode disposed on the substrate and corresponding to a plurality of pixels, and disposed between the adjacent lower electrodes on the substrate. And a lower electrode and an organic material layer disposed on the bank, and a non-existing region in which at least a part of the organic material layer does not partially exist is formed on the bank. ing.
[Selection] Figure 3

Description

  The present invention relates to an organic EL display device and a method for manufacturing the organic EL display device.

  An organic electroluminescence (EL) display device has a display panel in which a thin film transistor (TFT), an organic light emitting diode (OLED), and the like are formed on a substrate. An OLED includes an organic material layer between a pair of electrodes. The organic material layer is configured by stacking, for example, a hole transport layer, a light emitting layer, an electron transport layer, and the like. Such an organic material layer is typically formed in a region surrounded by a convex bank provided in advance for partitioning pixels. Here, for example, when a conductive material such as a hole transport layer is provided in common between a plurality of pixels, there is a problem that a leak current flows between adjacent pixels. Specifically, there is a problem in that adjacent pixels that should not emit light due to a leak current emit light, leading to a decrease in contrast and color purity. Such a problem may become more prominent as the definition becomes higher (for example, the distance between adjacent pixels becomes shorter) and the driving voltage is reduced (for example, adoption of a high mobility material).

  For example, in Japanese Patent Application Laid-Open Publication No. 2004-228620, for example, a method of irradiating an organic material layer on a bank with energy rays to denature a conductive layer included in the organic material layer to make it nonconductive. Proposed.

JP 2016-18759 A

  However, it is desired to more reliably suppress the leakage current between adjacent pixels.

  In view of the above, an object of the present invention is to provide an organic EL display device that can more reliably suppress a leakage current between adjacent pixels and a manufacturing method thereof.

  The organic EL display device of the present invention is disposed between a substrate, a lower electrode disposed on the substrate and corresponding to a plurality of pixels, and an adjacent lower electrode on the substrate, and partitions the plurality of pixels. A non-existing region that includes a bank and the lower electrode and an organic material layer disposed on the bank and in which at least a part of the organic material layer does not partially exist is formed on the bank.

  In one embodiment, a part of the organic material layer includes a hole transport layer.

  In one embodiment, the organic EL display device includes an upper electrode disposed on the organic material layer, and the upper electrode is in contact with the bank in a non-existing region on the bank.

  According to another aspect of the present invention, a method for manufacturing an organic EL display device is provided. In this method of manufacturing an organic EL display device, a lower electrode corresponding to a plurality of pixels is formed on a substrate, and a bank for partitioning the plurality of pixels is formed between adjacent lower electrodes on the substrate. Forming an organic material layer on the lower electrode and the bank, and removing the organic material layer existing on the bank in this order.

  In one embodiment, the organic material layer existing on the bank is removed by transferring it to an adhesive sheet.

  In one embodiment, in the manufacturing method, the organic material layer includes a hole transport layer.

  In one embodiment, the manufacturing method further includes forming an upper electrode on the organic material layer after the removal.

1 is a schematic diagram illustrating a schematic configuration of an organic EL display device according to an embodiment of the present invention. FIG. 2 is a schematic plan view illustrating an example of a display panel of the organic EL display device illustrated in FIG. 1. It is a figure which shows an example of the III-III cross section of FIG. It is a schematic sectional drawing for demonstrating the formation method of a non-existing area | region. It is a schematic sectional drawing for demonstrating the formation method of a non-existing area | region.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, about drawing, the same code | symbol is attached | subjected to the same or equivalent element, and the overlapping description may be abbreviate | omitted.

  FIG. 1 is a schematic diagram showing a schematic configuration of an organic EL display device according to an embodiment of the present invention. The organic EL display device 2 includes a pixel array unit 4 that displays an image and a drive unit that drives the pixel array unit 4. The organic EL display device 2 has a display panel in which a laminated structure such as TFT and OLED is formed on a substrate. The schematic diagram shown in FIG. 1 is an example, and the present embodiment is not limited to this.

  In the pixel array unit 4, OLEDs 6 and pixel circuits 8 are arranged in a matrix corresponding to the pixels. The pixel circuit 8 includes a plurality of TFTs 10 and 12 and a capacitor 14.

  The drive unit includes a scanning line drive circuit 20, a video line drive circuit 22, a drive power supply circuit 24, and a control device 26, and drives the pixel circuit 8 to control light emission of the OLED 6.

  The scanning line driving circuit 20 is connected to a scanning signal line 28 provided for each horizontal arrangement (pixel row) of pixels. The scanning line driving circuit 20 sequentially selects the scanning signal lines 28 according to the timing signal input from the control device 26, and applies a voltage for turning on the lighting TFT 10 to the selected scanning signal lines 28.

  The video line driving circuit 22 is connected to a video signal line 30 provided for each vertical arrangement (pixel column) of pixels. The video line driving circuit 22 receives a video signal from the control device 26, and in accordance with the selection of the scanning signal line 28 by the scanning line driving circuit 20, a voltage corresponding to the video signal of the selected pixel row is applied to each video signal line. Output to 30. The voltage is written into the capacitor 14 via the lighting TFT 10 in the selected pixel row. The driving TFT 12 supplies a current corresponding to the written voltage to the OLED 6, whereby the OLED 6 of the pixel corresponding to the selected scanning signal line 28 emits light.

  The drive power supply circuit 24 is connected to a drive power supply line 32 provided for each pixel column, and supplies a current to the OLED 6 through the drive power supply line 32 and the drive TFT 12 of the selected pixel row.

  Here, the lower electrode of the OLED 6 is connected to the driving TFT 12. On the other hand, the upper electrode of each OLED 6 is configured by an electrode common to the OLED 6 of all pixels. When the lower electrode is configured as an anode (anode), a high potential is input, and the upper electrode is a cathode (cathode) and a low potential is input. When the lower electrode is configured as a cathode (cathode), a low potential is input, and the upper electrode is an anode (anode) and a high potential is input.

  FIG. 2 is a schematic plan view showing an example of the display panel of the organic EL display device shown in FIG. The pixel array unit 4 shown in FIG. 1 is provided in the display area 42 of the display panel 40, and the OLEDs are arranged in the pixel array unit 4 as described above. As described above, the upper electrode 44 constituting the OLED 6 is formed in common for each pixel and covers the entire display region 42.

  A component mounting area 46 is provided on one side of the rectangular display panel 40, and wirings connected to the display area 42 are arranged. In the component mounting area 46, a driver integrated circuit (IC) 48 constituting a driving unit is mounted or an FPC 50 is connected. A flexible printed circuit board (FPC) 50 is connected to the control device 26 and other circuits 20, 22, 24, etc., and an IC is mounted thereon.

  FIG. 3 is a diagram illustrating an example of a III-III cross section of FIG. 2. The display panel 40 has a structure in which a circuit layer made of a TFT 72 and the like, an OLED 6 and a sealing layer 106 for sealing the OLED 6 are stacked on a substrate 70. The board | substrate 70 is comprised with a glass plate and a resin film, for example. In the present embodiment, the pixel array unit 4 is a top emission type, and the light generated by the OLED 6 is emitted to the side opposite to the substrate 70 side (upward in FIG. 3).

  In the circuit layer of the display area 42, the pixel circuit 8, the scanning signal line 28, the video signal line 30, the drive power supply line 32, and the like are formed. At least a part of the driving unit can be formed as a circuit layer on the substrate 70 in a region adjacent to the display region 42. As described above, the driver IC 48 and the FPC 50 constituting the driving unit can be connected to the wiring 116 of the circuit layer in the component mounting region 46.

As shown in FIG. 3, a base layer 80 made of an inorganic insulating material is disposed on the substrate 70. As the inorganic insulating material, for example, silicon nitride (SiN _y ), silicon oxide (SiO _x ), and a composite thereof are used.

  In the display region 42, a semiconductor region 82 serving as a channel portion and a source / drain portion of the top gate TFT 72 is formed on the substrate 70 through the base layer 80. The semiconductor region 82 is formed of, for example, polysilicon (p-Si). The semiconductor region 82 is formed, for example, by providing a semiconductor layer (p-Si film) on the substrate 70, patterning the semiconductor layer, and selectively leaving a portion used in the circuit layer. A gate electrode 86 is disposed on the channel portion of the TFT 72 via a gate insulating film 84. The gate insulating film 84 is typically formed of TEOS. The gate electrode 86 is formed by patterning a metal film formed by sputtering or the like, for example. An interlayer insulating layer 88 is disposed on the gate electrode 86 so as to cover the gate electrode 86. The interlayer insulating layer 88 is formed of, for example, the above inorganic insulating material. Impurities are introduced into the semiconductor region 82 (p-Si) serving as the source / drain portion of the TFT 72 by ion implantation, and further, a source electrode 90a and a drain electrode 90b electrically connected thereto are formed, and the TFT 72 is configured. Is done.

  An interlayer insulating film 92 is disposed on the TFT 72. A wiring 94 is disposed on the surface of the interlayer insulating film 92. For example, the wiring 94 is formed by patterning a metal film formed by sputtering or the like. The metal film forming the wiring 94 and the metal film used for forming the gate electrode 86, the source electrode 90a, and the drain electrode 90b include, for example, the wiring 116 and the scanning signal line 28, the video signal line 30, and the like shown in FIG. The drive power supply line 32 can be formed with a multilayer wiring structure. On this, for example, a planarizing film 96 is formed of a resin material such as acrylic resin, and the OLED 6 is formed on the planarizing film 96 in the display region 42.

  The OLED 6 includes a lower electrode 100, an organic material layer 102, and an upper electrode 104. The organic material layer 102 is formed by stacking, for example, a hole transport layer, a light emitting layer, and an electron transport layer. The OLED 6 is typically formed by laminating the lower electrode 100, the organic material layer 102, and the upper electrode 104 in this order from the substrate 70 side. In this embodiment, the lower electrode 100 is an anode (anode) of the OLED, and the upper electrode 104 is a cathode (cathode). Note that the organic material layer may have a layer other than the above. Examples of the other layers include a hole injection layer and an electron blocking layer disposed between the anode and the light emitting layer, and an electron injection layer and a hole blocking layer disposed between the cathode and the light emitting layer. .

  If the TFT 72 shown in FIG. 3 is a driving TFT 12 having an n channel, the lower electrode 100 is connected to the source electrode 90 a of the TFT 72. Specifically, after the above-described planarization film 96 is formed, a contact hole 110 for connecting the lower electrode 100 to the TFT 72 is formed. For example, the surface of the planarization film 96 and the conductor portion formed in the contact hole 110. By patterning, the lower electrode 100 connected to the TFT 72 is formed for each pixel.

  On the above structure, banks 112 for partitioning pixels are arranged. For example, after the formation of the lower electrode 100, a bank 112 is formed at the pixel boundary, and the organic material layer 102 and the upper electrode 104 are stacked in an effective region (region where the lower electrode 100 is exposed) surrounded by the bank 112. The The bank 112 is typically formed of a resin material such as polyimide resin or acrylic resin. The upper electrode 104 is typically formed of a transparent electrode material. A non-existing region 108 in which the organic material layer 102 does not substantially exist is formed on the bank 112. In the nonexistent region 108, the upper electrode 104 is in contact with the bank 112. Since the organic material layer 102 is not continuously formed between adjacent pixels, generation of the above-described leakage current is effectively suppressed. Note that, in the non-existing region 108, unlike the illustrated example, even if a part of the layer constituting the organic material layer 102 (for example, a relatively thick hole transport layer) is not selectively present. Good. Further, the non-existing region 108 may be formed between all the pixels, or selectively leaks around a specific pixel (for example, among red (R), green (G), and blue (B)). May be selectively formed around the G pixel in which the color purity is significantly reduced.

  4A and 4B are schematic cross-sectional views for explaining a method for forming the non-existing region 108. 4A and 4B, the stacked structure from the base layer 80 to the planarizing film 96 on the substrate 70 in the stacked structure of the display panel 40 shown in FIG. . As shown in FIG. 4A, between the adjacent lower electrodes 100, 100 on the substrate 70, a bank 112 for partitioning pixels is formed so as to protect the end portion of the lower electrode 100, and the lower electrode 100 and the bank 112 are formed. The organic material layer 102 is formed continuously. For example, a hole transport layer 102a containing a compound having a triphenylamine structure is continuously formed on the lower electrode 100 and the bank 112 (provided in common among a plurality of pixels). A light emitting layer 102b corresponding to the color of the pixel is formed in each pixel region, an electron transport layer 102c is formed so as to cover the light emitting layer 102b (common to a plurality of pixels), and an organic material layer 102 is formed. The adhesive surface of the adhesive sheet 60 is bonded onto the formed organic material layer 102, and the organic material layer 102d existing on the bank 112 is transferred to the adhesive sheet 60 as shown in FIG. 4B. In this way, after removing a part 102 d of the organic material layer and forming the non-existing region 108 on the bank 112, the upper electrode 104 is formed on the organic material layer 102. As described above, when the hole transport layer 102a is selectively removed, for example, the adhesive sheet 60 is bonded onto the bank 112 immediately after the formation of the hole transport layer 102a.

  The pressure-sensitive adhesive sheet 60 is, for example, a laminate including a base material and a pressure-sensitive adhesive layer formed on one side of the base material. When removing a part of the organic material layer 102, the pressure-sensitive adhesive sheet 60 may be in a sheet shape or may be wound in a roll shape.

A sealing layer 106 is disposed on the upper electrode 104. The sealing layer 106 can function as a protective layer that protects the OLED 6 from moisture or the like, and is formed so as to cover the entire display region 42. The sealing layer 106 is formed, for example, by depositing an inorganic insulating material film such as SiN _y by a chemical vapor deposition (CVD) method. Although not shown, for example, a protective film may be disposed on the surface of the display region 42 in order to ensure the mechanical strength of the surface of the display panel 40. In this case, in the component mounting region 46, a protective film is usually not provided in order to facilitate connection of an IC or FPC. The wiring of the FPC 50 and the terminal of the driver IC 48 are electrically connected to the wiring 116, for example.

  The present invention is not limited to the above embodiment, and various modifications can be made. For example, it can be replaced with a configuration that is substantially the same as the configuration shown in the above embodiment, a configuration that exhibits the same operational effects, or a configuration that can achieve the same purpose. Specifically, in the above-described embodiment, the non-existing region 108 is formed by partially removing the organic material layer 102 using an adhesive sheet. For example, the non-existing region 108 is removed by laser processing (cutting, ablation). Or by removal (cutting, cutting) using a cutter or a cutter.

  2 organic EL display device, 4 pixel array unit, 6 OLED, 8 pixel circuit, 10 lighting TFT, 12 driving TFT, 14 capacitor, 20 scanning line driving circuit, 22 video line driving circuit, 24 driving power supply circuit, 26 control device, 28 scanning signal lines, 30 video signal lines, 32 drive power supply lines, 40 display panel, 42 display area, 44 upper electrode, 46 component mounting area, 48 driver IC, 50 FPC, 60 adhesive sheet, 70 substrate, 72 TFT, 80 Base layer, 82 semiconductor region, 84 gate insulating film, 86 gate electrode, 88 interlayer insulating layer, 90a source electrode, 90b drain electrode, 92 interlayer insulating film, 94 wiring, 96 planarization film, 100 lower electrode, 102 organic material layer 104 Upper electrode 106 Sealing layer 108 Non-existing region 110 Contact hole Le, 112 banks, 114 upper structural layer, 116 a wiring.

Claims (7)

A substrate,
A lower electrode disposed on the substrate and corresponding to a plurality of pixels;
A bank disposed between adjacent lower electrodes on the substrate and defining the plurality of pixels;
An organic material layer disposed on the lower electrode and the bank,
A non-existing region in which at least a part of the organic material layer does not exist partially is formed on the bank.
Organic EL display device.   The organic EL display device according to claim 1, wherein a part of the organic material layer includes a hole transport layer. An upper electrode disposed on the organic material layer;
The organic EL display device according to claim 1, wherein the upper electrode is in contact with the bank in a non-existing region on the bank. Forming a lower electrode corresponding to a plurality of pixels on a substrate;
Forming a bank for partitioning the plurality of pixels between the adjacent lower electrodes on the substrate;
Forming an organic material layer on the lower electrode and the bank;
Removing the organic material layer present on the bank;
In this order.   The manufacturing method according to claim 4, wherein the organic material layer existing on the bank is removed by being transferred to an adhesive sheet.   The manufacturing method according to claim 4, wherein the organic material layer includes a hole transport layer.   The manufacturing method according to claim 4, further comprising forming an upper electrode on the organic material layer after the removal.

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