JP2015011761A - Oled display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an OLED display panel capable of shielding a high-frequency noise while preventing electrostatic breakdown even for such an OLED display panel in which a counter substrate is omitted.SOLUTION: An OLED light-emitting device including a TFT layer 12 and an OLED layer 15 formed on a substrate 11 is covered with a sealing layer 18 formed of an insulation material. A transparent conductive film 19 is formed on an upper surface of this sealing layer 18. The whole of an OLED display panel 100 formed in this way is housed in a metal box-shaped module housing 20. In addition, between the transparent conductive film 19 and an edge of the module housing 20, a conductive part 21 consisted of a conductive tape is adhered over the whole circumference.

Description

  The present invention relates to an OLED (organic light-emitting diode) display panel.

  In recent years, OLED display panels have been developed for the purpose of reducing the thickness, increasing the brightness, and increasing the speed of display panels. This OLED display panel is a display panel composed of at least three organic compound light-emitting diodes (OLED light-emitting elements) in which each pixel emits light of three primary colors (red, green, and blue). This is expected to be a next-generation display panel because it has a high response speed because each pixel itself emits light, enabling high-brightness display, and because it eliminates the need for a backlight. ing.

  In such an OLED display panel, a large number of OLED light emitting elements corresponding to each pixel of an image to be displayed are formed in a matrix on a single substrate (glass substrate), and incident external light is further formed thereon. It has a structure in which a transparent counter substrate for prevention is laminated.

  Specifically, as shown in FIG. 5, the OLED light emitting element is roughly composed of a drive circuit layer 34 and an OLED layer 35. The drive circuit layer 34 includes a first insulating layer 36 formed on the upper surface of the glass substrate 31, a TFT layer 38 including a field effect transistor formed by patterning on the insulating layer 36, and the TFT layer 38. An anode 33 that is conducted to the drain of the encapsulated field effect transistor is a main component.

  The OLED layer 35 is formed on the anode 33 so as to separate the organic EL layer 25 formed to have a similar shape to the anode 33 from the organic EL layers 25 of other adjacent pixels. The rib layer 24, the organic EL layer 25, the transparent cathode 26 formed on the upper surface of the rib layer 24, and the sealing layer 27 formed so as to cover the transparent cathode 26 are the main constituent elements. .

  The SOC member 29 is a frame member formed from a photocurable acrylic resin. The SOC member 29 functions as a gap spacer that keeps the distance between the upper surface of the glass substrate 31 (the upper surface of the TFT layer 18) and the lower surface of the counter substrate 32 constant. In this way, the space secured between the upper surface of the glass substrate 31 (the upper surface of the TFT layer 38) and the lower surface of the counter substrate 32 is filled with a transparent filler 28 made of an epoxy resin.

Furthermore, on the surface of the counter substrate 2, when a conductor such as an operator's finger or a hard body such as a touch pen comes into contact, a touch panel as a pointing device that outputs a signal corresponding to the contact position is provided. Is formed.

JP 2009-30029 JP

  However, when an operator's finger or touch pen touches the touch panel, static electricity is generated due to dielectric polarization, and charge-up due to the external static electricity may occur in the OLED display panel. As a result, the OLED light emitting element is destroyed. The problem of (electrostatic breakdown) occurs.

  Further, since the signal for driving the OLED light emitting element is a rectangular wave, it includes a high frequency component, and this high frequency component enters the touch panel via electromagnetic induction and is superimposed on the output signal of the touch panel as high frequency noise. Arise.

  In LCD (Liquid Crystal Display), a thin film layer of ITO (Indium Tin Oxide) is formed on the surface of the color filter substrate opposite to the liquid crystal layer, and connected to the ground potential of the TFT (Thin Film Transistor) substrate. Therefore, it has been practical to shield the static electricity and high frequency noise as described above. For this reason, it may be possible to divert such a shield technology to an OLED display panel. However, if the OLED display panel is to be made thin or flexible, the opposing substrate must be omitted. Can not do it.

In view of the above, an object of the present invention is to provide an OLED display panel that can shield high-frequency noise and prevent electrostatic breakdown even if the OLED display panel omits the counter substrate. It is.

  An OLED display panel according to the present invention is an OLED display panel including an OLED light emitting element that emits light by recombination of holes and electrons in an organic EL layer, and an outer surface on an upper surface of the substrate. A plurality of the OLED light-emitting elements formed in a region excluding the peripheral edge, and a sealing layer made of an insulator that covers the whole of the plurality of OLED light-emitting elements and the upper surface of the substrate and extends to the outer edge of the substrate; A transparent conductive film formed on the entire top surface of the sealing layer; and a housing made of a conductive material that covers the bottom surface of the substrate and the side surfaces of the substrate and the sealing layer and is in contact with the outer edge of the transparent conductive film. It is characterized by having.

According to the OLED display panel of the present invention configured as described above, high-frequency noise can be shielded and electrostatic breakdown can be prevented even though the counter substrate is omitted.

The top view of the OLED display panel by Embodiment 1 Schematic longitudinal sectional view of OLED display panel Enlarged vertical cross section near the edge of the OLED display panel Enlarged longitudinal sectional view of the vicinity of the edge of the OLED display panel according to the second embodiment Vertical section of a conventional OLED display panel

Hereinafter, the best mode for carrying out the OLED display panel 100 according to the present invention will be described with reference to the drawings. Each of the following embodiments relates to the OLED display panel 100 in which the counter substrate is omitted in order to realize a reduction in thickness and to provide some flexibility to itself. In each of the following embodiments, high-frequency noise generated in the TFT drive circuit of the OLED light-emitting element and the organic light-emitting layer leaks to the outside of the OLED display panel 100 and causes an input device such as a touch panel provided separately to malfunction. OLED display panel in order to prevent external static electricity (electric field) from causing polarization charges (charge-up) in OLED display panel 100 and destroying OLED light emitting elements (electrostatic breakdown) The entire 100 is sealed with a series of conductors to produce an electrostatic shielding effect.
(Embodiment 1)

  FIG. 1 is a plan view of an OLED display panel 100 according to the present embodiment, FIG. 2 is a longitudinal sectional view thereof, and FIG. 3 is a partially enlarged longitudinal sectional view in the vicinity of an edge. In addition, the dashed-dotted line in FIG. 3 has shown that the structure was continued also on the left side of the dashed-dotted line, but illustration was abbreviate | omitted.

  As shown in FIG. 1, a set of three OLED light emitting elements for displaying one pixel in color by emitting three primary colors (red, green, and blue) in the center of the OLED display panel 100 in a plan view. A large number of groups are arranged in a matrix, and a display area 1 on which an image is displayed is formed by selectively driving these OLED light emitting elements while adjusting the light emission amount. In addition, a driving circuit (X driver) for driving each OELD display element in the display area 1 selectively and by adjusting the amount of light emission is provided at three places on the upper surface of the OLED display panel 100 in the peripheral area of the display area 1. , Y driver, shift register, etc.) 3 and 4 are provided. With these configurations, the display area 1 can display a full-color image. Further, in the vicinity of the edge near the drive circuit 3 in the OLED display panel 100, the drive circuits 3 and 4 are electrically connected to supply a power supply voltage and a drive signal to the drive circuits 3 and 4, and to the ground. The connector 2 for grounding is formed by a striped metal thin film.

  As shown in FIGS. 2 and 3, the OLED display panel 100 is manufactured by laminating a thin film on the surface of a substrate 11 as a base. As a material of the substrate 11, a synthetic resin that is an insulating material is used in order to give flexibility to the entire OLED display panel 100.

  On the surface corresponding to the display area 1 on the surface of the substrate 11, a TFT layer 12 including a gate, source and drain metal wirings and a field effect transistor made of a semiconductor is formed for each OLED light emitting element. ing. On the TFT layer 12, a flattening layer 13 made of an insulating material that insulates each field effect transistor and fills the unevenness on the upper surface of the TFT layer 12 to be flattened is formed. At the position where each OLED light-emitting element is formed on the upper surface of the planarizing layer 13, an anode 14 formed according to the shape of the OLED light-emitting element is formed. Each anode 14 is electrically connected to the drain wiring of the field effect transistor for each OLED light emitting element through a contact hole 13a penetrating the planarizing layer 13 vertically.

  On each anode 14, an OLED layer 15 formed in a similar shape is formed. Specifically, the OLED layer 15 has a structure in which a hole injection layer, a hole transport layer, an organic EL (Electro Luminescence) light emitting layer, an electron transport layer, and an electron injection layer are laminated in order from the anode 14 side. doing. As a material of the organic EL light emitting layer constituting the OLED layer 15, as described above, a material that emits light of any one of the three colors of red, green, and blue is employed.

  The OLED layers 15 of the respective OLED light emitting elements are partitioned from each other by a rib layer 16 made of an insulating material. A transparent common cathode 17 is formed so as to be in contact with the surface of the OLED layer 15 (electron injection layer) of all the OLED light-emitting elements and to cover the OLED layer 15 (electron injection layer) together with the rib layer 16. Has been. The TFT layer 12, the planarization layer 13, the anode 14, the OLED layer 15, and the rib layer 16 described above are not formed up to the outer edge of the substrate 11, so the outer edge of the common cathode 17 reaches the surface of the substrate 11. However, the outer edge of the substrate 11 is not reached.

  The entire surface of the surface of the common cathode 17 and the portion of the surface of the substrate 11 that is not covered with the common cathode 17 is covered with a sealing layer 18 for the purpose of blocking moisture. For example, SiN is used as the material of the sealing layer 18.

  Furthermore, a transparent conductive film layer 19 made of a transparent conductive material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) is formed on the entire surface of the sealing layer 18, and this is the OLED display panel 100. Is the outermost layer.

  Outside the display area, a sealing layer 18 and a transparent conductive layer 19 are formed on the upper surface of the substrate 11, and the sealing layer 18 and the transparent conductive layer 19 extend to the outer edge of the substrate 11. It is. However, as shown in FIG. 1, at the location where the connector 2 is formed, the flexible printed circuit board (FPC board) 7 that supplies drive power, drive signal, and ground potential from the outside is connected to the connector 2. The sealing layer 18 and the transparent conductive layer 19 are removed.

  On the other hand, the OLED display panel 100 configured as described above is accommodated in a module housing 20 made of metal (conductive material) having a box shape with a flat rectangular shape and an open upper surface. That is, the bottom surface of the substrate 11 constituting the OLED display panel 100 and the side surfaces of the substrate 11 and the sealing layer 18 are covered with the module housing 22. Note that the depth of the internal space of the module housing 20 matches the thickness of the OLED display panel 100 at the outer edge of the substrate 11 (the thickness from the bottom surface of the substrate 11 to the surface of the transparent conductive film layer 19). Therefore, the edge of the module housing 20 and the surface of the transparent conductive film layer 19 are flush with each other, and the two are electrically connected. In order to ensure conduction between the module housing 20 and the transparent conductive film layer 19 and complete a closed conductor, a conductive film is provided between the side surface and the upper surface of the module housing 20 and the transparent conductive film layer 19. Conductive portions 21 made of a conductive material are bridged and are electrically connected to each other. Specifically, the conductive portion 21 is a conductive resin or a conductive tape.

  Since the module housing 20 is connected to a constant potential (for example, the ground potential or the ground potential of the battery), the module housing 20 and the transparent conductive film 19 conducted to the module housing 20 can be electrostatic Functions as a shield. Therefore, the high frequency noise generated by each OLED element of the OLED display panel 100 sealed by the module casing 20 and the transparent conductive film 19 may cause electromagnetic induction beyond the module casing 20 and the transparent conductive film 19. As a result, there is no effect on devices installed outside the module housing 20 and the transparent conductive film 19. For example, even when a touch panel is installed over the transparent conductive film 19, high frequency noise generated by each OLED element does not cause the touch panel to malfunction. In addition, since static electricity generated outside the module housing 20 and the transparent conductive film 19 does not cause polarization charges (charge-up) in the module housing 20 and the transparent conductive film 19, each of the OLED display panels 100 is provided. The OLED element is not electrostatically destroyed.

As described above, according to the OLED display panel 100 of the present embodiment, the entire OLED display panel 100 is sealed with a series of conductors (the transparent conductive film 19 and the module casing 20). Due to the electrostatic shield effect that blocks the electric field, not only the high-frequency noise can be blocked, but also the influence of the electrostatic field caused by static electricity can be completely prevented. That is, it is not necessary to use a counter substrate to solve the problems of high frequency noise and electrostatic breakdown. Therefore, the structure of the OLED display panel 100 can be a thin structure that does not include a counter substrate and at least a surface that is flexible.
(Embodiment 2)

  The second embodiment of the present invention is characterized in that a polarizing plate 23 is attached on the transparent conductive film 19 via an adhesive layer 22 as compared with the first embodiment described above. The adhesive layer 22 is a transparent epoxy adhesive similar to that filled between the counter substrate in the conventional OLED display panel 100. The polarizing plate 23 is an optical element including a linearly polarizing filter and a circularly polarizing filter, which are the same as those conventionally used for preventing reflection of external light. When the OLED display panel 100 is configured flexibly, the polarizing plate 23 can be configured from a synthetic resin plate.

  The other configurations and effects in the second embodiment of the present invention are exactly the same as those in the first embodiment described above, and thus the description thereof is omitted.

11 Substrate 12 TFT layer 15 OLED layer 17 Common cathode 18 Sealing layer 19 Transparent conductive film 20 Module housing 100 OLED display panel

Claims (6)

An OLED display panel including an OLED light emitting element that emits light by recombination of holes and electrons in an organic EL layer,
A substrate made of an insulating material;
A plurality of the OLED light emitting elements formed in a region excluding the outer peripheral edge on the upper surface of the substrate;
A sealing layer made of an insulating material covering the whole of the plurality of OLED light emitting elements and the upper surface of the substrate and extending to the outer edge of the substrate;
A transparent conductive film formed on the entire top surface of the sealing layer;
An OLED display panel comprising: a housing made of a conductive material that covers a bottom surface of the substrate and side surfaces of the substrate and the sealing layer and contacts an outer edge of the transparent conductive film. The OLED display panel according to claim 1, further comprising a conductive member that spans between an outer edge of the transparent conductive film and an edge of the casing. 3. The OLED display panel according to claim 2, wherein the conductive member is stretched over an entire outer periphery of the transparent conductive film and an edge of the casing. 4. The OLED display panel according to claim 3, wherein the conductive member is a tape made of a conductive material. The OLED display panel according to claim 1, wherein a polarizing plate is attached on the transparent conductive film via a transparent adhesive layer. The OLED display panel according to claim 1, wherein the casing is a metal box.

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