JP7650654B2 - Display device and manufacturing method thereof - Google Patents

Description

The present invention relates to a display device and a manufacturing method thereof.

For example, organic EL display devices (organic EL displays) that use organic electroluminescence (EL) elements are highly luminous and self-luminous, can be driven at a low DC voltage, have fast response, and emit light from a solid organic film. As a result, they have excellent display performance and can be made thin, lightweight, and consume less power. For these reasons, they are expected to replace liquid crystal display devices in the future.

Specifically, an organic EL display device has a display panel including a display area in which a plurality of pixels are arranged in a matrix on a surface. The display panel includes a plurality of scanning lines (gate lines), a plurality of signal lines (data lines), and a plurality of power lines (power lines) arranged in the horizontal and vertical directions on the surface of the display area, and a pixel circuit that constitutes the above-mentioned pixels is provided in each area partitioned by the plurality of scanning lines and the plurality of signal lines.

The display panel has a pixel circuit that includes an organic EL element, which is a light-emitting element, a capacitor, which is a storage capacitance, and two thin film transistor (TFT) elements, which are switching elements. In the display panel, the potential (image data) of the signal line is stored in the storage capacitance connected to the signal line via the selection TFT element through the switching operation of the selection TFT element connected to the scan line. In addition, depending on the potential of the storage capacitance, a drive current flows through the organic EL element connected to the power line via the drive TFT element. This makes it possible to cause the organic EL element to emit light (light up).

The display panel also has a peripheral area called a bezel (frame) that surrounds the periphery of the display area. In the peripheral area, a number of connection parts corresponding to a number of scanning lines and a number of signal lines that are drawn out to the outside of the display area are arranged in the horizontal and vertical directions of the peripheral area. The multiple scanning lines and multiple signal lines are electrically connected to an external drive circuit (driver) via a flexible printed circuit board (FPC) that is connected to the multiple connection parts.

However, the conventional display devices described above require a TFT circuit to correct the characteristic fluctuations and variations over time of the TFT elements and organic EL elements, which can result in a more complicated structure (see, for example, Patent Document 1 below).

In addition, in order to improve image quality, there is a demand for higher definition in organic EL display devices, and pixel size needs to be reduced. For example, in the case of a top emission structure in which an organic EL element is formed on top of a pixel circuit and light is extracted from the top of the organic EL element, the pixel size depends heavily on the area of the pixel circuit, which is composed of the above-mentioned TFT element and storage capacitor. In order to reduce this area, efforts are being made to reduce the area by improving the TFT structure, and to develop methods for producing TFT circuits with smaller channel sizes.

Also, in organic EL display devices, a method has been proposed in which two TFT elements are arranged in the vertical direction rather than in the horizontal direction, thereby reducing the area of the pixel circuit and achieving high definition (see, for example, Non-Patent Document 1 below).

However, in the method described in Non-Patent Document 1, when TFT elements are stacked vertically, a manufacturing process for the TFT elements must be carried out according to the number of stacked TFT elements. This results in a decrease in throughput.

For example, in the method described in Non-Patent Document 1, since two TFT elements are stacked, the TFT element manufacturing process must be carried out twice, approximately doubling the number of manufacturing processes. In addition, the film-forming process, processing process, heating process, and the like used in manufacturing the upper TFT element may damage the lower TFT element. Furthermore, the presence of the lower TFT element may result in a surface that is less flat than the substrate when manufacturing the upper TFT element. In this case, it becomes difficult to manufacture the upper TFT element and to obtain good characteristics for the upper TFT element.

Patent No. 4103850

“Vertically integrated, double stack oxide TFT layers for high-resolution AMOLED backplane” Journal Society for Information Display.2020;28:469-475 (DOI:10.1002/jsid.907)

The present invention has been proposed in light of the above-mentioned conventional circumstances, and aims to provide a display device and a manufacturing method thereof that can reduce the area of the pixel circuit and achieve high definition.

In order to achieve the above object, the present invention provides the following means.
[1] A display panel including a display area in which a plurality of pixels are arranged in a plane,
the display panel includes a pixel circuit substrate on which pixel circuits constituting the pixels are provided,
the pixel circuit includes a light-emitting element, and a first switching element and a second switching element that switch the lighting of the light-emitting element;
the pixel circuit substrate has a structure in which a first substrate on which the light-emitting element and the first switching element are provided and a second substrate on which the second switching element is provided are laminated, and the first substrate and the second substrate are electrically connected to each other via a connection portion;
the first switching element is disposed on one surface side of the first substrate, and is electrically connected to a first connection wiring disposed on the other surface side of the first substrate via a first contact plug disposed to penetrate the first substrate;
the first connection wiring is formed integrally with the first contact plug by using the same conductive material as the first contact plug;
the second switching element is disposed on one surface side of the second substrate, and is electrically connected to a second connection wiring disposed on the interlayer insulating layer via a second contact plug disposed to penetrate the interlayer insulating layer covering the one surface side of the second substrate,
the second connection wiring is formed integrally with the second contact plug by using the same conductive material as the second contact plug;
A display device characterized in that the first connection wiring and the second connection wiring are electrically connected via the connection portion while the other surface of the first substrate and one surface of the second substrate are opposed to each other.
[2] A display panel including a display area in which a plurality of pixels are arranged in a plane,
the display panel includes a pixel circuit substrate on which pixel circuits constituting the pixels are provided,
the pixel circuit includes a light-emitting element, and a first switching element and a second switching element that switch the lighting of the light-emitting element;
the pixel circuit substrate has a structure in which a first substrate on which the light-emitting element and the first switching element are provided and a second substrate on which the second switching element is provided are laminated, and the first substrate and the second substrate are electrically connected to each other via a connection portion;
the first switching element is disposed on one surface side of the first substrate and is electrically connected to a first contact plug disposed to penetrate the first substrate;
the second switching element is disposed on one surface side of the second substrate and is electrically connected to a second contact plug disposed to penetrate the second substrate;
the first contact plug and the second contact plug are formed using the same conductive material;
A display device characterized in that the first contact plug and the second contact plug are electrically connected via the connection portion with the other surface of the first substrate facing the other surface of the second substrate.
[3] The display device according to [1] or [2], wherein the connection portion is formed using the same conductive material as the first contact plug and the second contact plug.
[4] The display device according to any one of [1] to [3], characterized in that at least one circuit board is laminated on the surface of the second substrate opposite to the surface facing the first substrate.
[5] The display device according to [4], wherein the circuit board includes a drive circuit board on which a drive circuit for driving the pixel circuits is provided.
[6] A method for manufacturing a display device including a display panel including a display region in which a plurality of pixels are arranged in a plane, comprising the steps of:
When manufacturing the display panel, a step of manufacturing a pixel circuit substrate on which a pixel circuit constituting the pixel is provided is included,
the pixel circuit includes a light-emitting element, and a first switching element and a second switching element that switch the lighting of the light-emitting element;
In the step of manufacturing the pixel circuit substrate, when a first substrate on which the light emitting element and the first switching element are formed and a second substrate on which the second switching element is formed are manufactured using a same mother substrate,
forming the first switching element, the second switching element, and an interlayer insulating layer on one surface side of the mother substrate;
a step of forming a contact hole penetrating the interlayer insulating layer at a position where the second switching element is to be formed, and then applying a conductive material onto the interlayer insulating layer and patterning the conductive material into a predetermined shape to integrally form a second contact plug embedded in the contact hole and a second connection wiring disposed on a surface of the interlayer insulating layer;
forming a contact hole penetrating the mother substrate at a position where the first switching element is to be formed, and then applying a conductive material to the other surface side of the mother substrate and patterning the conductive material into a predetermined shape to integrally form a first contact plug embedded in the contact hole and a first connection wiring disposed on the other surface side of the mother substrate;
After cutting the mother substrate into the first substrate and the second substrate,
A method for manufacturing a display device, characterized in that the first connection wiring and the second connection wiring are electrically connected via a connection portion while the other surface of the first substrate and one surface of the second substrate are opposed to each other.
[7] A method for manufacturing a display device including a display panel including a display region in which a plurality of pixels are arranged in a plane, comprising the steps of:
When manufacturing the display panel, a step of manufacturing a pixel circuit substrate on which a pixel circuit constituting the pixel is provided is included,
the pixel circuit includes a light-emitting element, and a first switching element and a second switching element that switch the lighting of the light-emitting element;
In the step of manufacturing the pixel circuit substrate, when a first substrate on which the light emitting element and the first switching element are formed and a second substrate on which the second switching element is formed are manufactured using a same mother substrate,
forming the first switching element and the second switching element on one surface side of the mother substrate;
forming contact holes penetrating the mother substrate at positions where the first switching element and the second switching element are to be formed, and then applying a conductive material to the other surface side of the mother substrate and patterning the conductive material into a predetermined shape to form a first contact plug and a second contact plug embedded in the contact holes;
After cutting the mother substrate into the first substrate and the second substrate,
A method for manufacturing a display device, characterized in that the first contact plug and the second contact plug are electrically connected via a connection portion while the other surface of the first substrate and the other surface of the second substrate are opposed to each other.

As described above, the present invention makes it possible to provide a display device and a manufacturing method thereof that can reduce the area of the pixel circuit and achieve high definition.

1 is a circuit diagram showing a configuration of a display device according to a first embodiment of the present invention. FIG. 2 is a circuit diagram showing a configuration of a pixel circuit. 2 is a cross-sectional view of a main part of a display panel taken along one direction. FIG. 11 is a cross-sectional view of a main part of the display panel taken along another direction. FIG. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel. 10 is a cross-sectional view of a main part along one direction of a display panel included in a display device according to a second embodiment of the present invention. FIG. 11 is a cross-sectional view of a main part of the display panel taken along another direction. FIG. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel. 11 is a cross-sectional view of a main part along one direction of a display panel included in a display device according to a third embodiment of the present invention. FIG. 11 is a cross-sectional view of a main part of the display panel taken along another direction. FIG. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel. 1A to 1C are cross-sectional views illustrating a process for manufacturing a display panel.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
In addition, the drawings used in the following description may show characteristic parts in a schematic manner for the sake of convenience in order to make the characteristics easier to understand, and the number of components and dimensional ratios are not necessarily the same as in reality. Furthermore, the materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not necessarily limited to them, and can be appropriately changed and implemented within the scope of the present invention.

(First embodiment)
[Display Device]
First, as a first embodiment of the present invention, a display device 1A shown in, for example, FIGS. 1 to 4 will be described.

Note that FIG. 1 is a circuit diagram showing the configuration of display device 1A. FIG. 2 is a circuit diagram showing the configuration of pixel circuit 3. FIG. 3 is a cross-sectional view of a main part of display panel 2A taken along one direction. FIG. 4 is a cross-sectional view of a main part of display panel 2A taken along another direction.

As shown in Figures 1, 2, and 3, the display device 1A of this embodiment is an organic EL display device (organic EL display) that uses organic EL elements to perform color display, to which the present invention is applied.

Specifically, this display device 1A has a display panel 2A including a display area E in which a plurality of pixels P are arranged side by side within a plane. The display panel 2A has a pixel circuit substrate 4 on which pixel circuits 3 that constitute the pixels P are provided.

The pixel circuit board 4 includes a plurality of scanning lines 5 arranged in one direction (vertical direction in FIGS. 1 and 2) that intersects within the plane of the display area E, and a plurality of signal lines 6 and a plurality of power lines 7 arranged in another direction (horizontal direction in FIGS. 1 and 2) that intersects within the plane of the display area E. The pixel circuit board 4 has a structure in which a pixel circuit 3 is provided for each area partitioned by the plurality of scanning lines 5, the plurality of signal lines 6, and the plurality of power lines 7.

The display panel 2A also has a structure in which a plurality of pixels (called "subpixels") P corresponding to at least the three primary colors of red (R), green (G), and blue (B) are grouped into one pixel unit (called a "pixel") Pu, and these pixel units Pu are periodically arranged within the plane.

In this embodiment, one pixel unit Pu is formed by arranging a pixel P corresponding to red (R), a pixel P corresponding to green (G), and a pixel P corresponding to blue (B) periodically in another direction. Also, in this embodiment, the pixel units Pu, which are rectangular in plan view, are arranged in a matrix on the surface of the display area E, which is rectangular in plan view, to form a display panel 2A, which is rectangular in plan view.

The pixel unit Pu is not necessarily limited to the above-mentioned configuration, and for example, it can be configured with four pixels P, including the pixel P corresponding to red (R), green (G), and blue (B) and a pixel P corresponding to white (W). Furthermore, it is not limited to a configuration in which a plurality of pixels P corresponding to the above-mentioned color display is arranged, and it is also possible to have a configuration in which a plurality of pixels P corresponding to monochrome display is arranged. Furthermore, the display area E and the display panel 2A are not necessarily limited to the above-mentioned rectangular shape, and their planar shape can be changed as appropriate.

As shown in Figures 2, 3, and 4, the pixel circuit 3 includes an organic EL element 8, which is a light-emitting element, a capacitor 9, which is a storage capacitance C, and two TFT elements, which are switching elements (a selection TFT element 10 and a drive TFT element 11).

The pixel circuit board 4 has a laminated structure of a first substrate 12A on which an organic EL element 8 and a driving TFT element 11 are provided, and a second substrate 12B on which a selection TFT element 10 is provided.

The first substrate 12A and the second substrate 12B are made of flexible substrates such as plastic substrates. In this embodiment, the first substrate 12A and the second substrate 12B are made of film-like plastic substrates having a thickness of, for example, 10 μm or less. The plastic substrate is made of a resin material such as polyimide.

The first substrate 12A and the second substrate 12B are not necessarily limited to the configuration using the flexible substrate described above, and may be configured using a rigid substrate such as a glass substrate.

The organic EL element 8 has a structure in which a pixel electrode 13, an organic functional layer 14, and a common electrode 15 are sequentially laminated on one surface (the front surface in FIG. 4) of the first substrate 12A. In other words, the organic EL element 8 has a structure in which the organic functional layer 14 is sandwiched between the pixel electrode 13, which is the positive electrode (+), and the common electrode 15, which is the negative electrode (-).

The pixel electrodes 13 are provided corresponding to each of the plurality of pixels P. The pixel electrodes 13 are made of a metal electrode material such as aluminum (Al). The pixel electrodes 13 are formed on an interlayer insulating layer 16 that covers the surface of the first substrate 12A on which the driving TFT elements 11 described below are formed. The interlayer insulating layer 16 is made of, for example, silicon oxide (SiO _x ). The pixel electrodes 13 are electrically connected to the source electrodes 11s of the driving TFT elements 11.

The organic functional layer 14 has a structure (called a "heterostructure") in which, for example, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer are stacked in this order. A bank layer 17 is provided on the interlayer insulating layer 16, except on the surface of the pixel electrode 13. The bank layer 17 is made of, for example, a coating-type organic insulating material. The organic functional layer 14 is embedded inside the bank layer 17.

The common electrode 15 constitutes a single solid electrode common to a plurality of pixels P. The common electrode 15 is made of a transparent electrode material such as indium tin oxide (ITO). The common electrode 15 is formed so as to cover the surface on which the organic functional layer 14 and the bank layer 17 are formed. In addition, a protective layer 18 is formed on the common electrode 15 so as to cover the entire surface of the first substrate 12A. The protective layer 18 is made of, for example, a coating-type organic insulating material.

The common electrode 15 is electrically connected to a GND line 19. The GND line 19 is provided on the surface of a gate insulating layer 20 that constitutes a driving TFT element 11 described later. The GND line 19 is electrically connected to the common electrode 15 via a contact plug 21a that penetrates the interlayer insulating layer 16, a contact electrode 21b formed on the interlayer insulating layer 16, and a contact plug 21c that penetrates the bank layer 17.

In the organic EL element 8, holes injected and transported from the pixel electrode 13 side through the hole injection layer and hole transport layer, and electrons injected and transported from the common electrode side through the electron injection layer and electron transport layer recombine in the light-emitting layer, making it possible to emit light.

The organic EL element 8 has a top emission structure in which light is extracted from one side of the first substrate 12A (hereinafter, one side of the first substrate 12A will be referred to as the "front side" and the other side of the first substrate 12A will be referred to as the "back side").

When a color display is performed using the organic EL element 8, a configuration is used in which an organic EL element that emits white light is combined with color filters corresponding to red (R), green (G), and blue (B). Alternatively, a configuration may be used in which organic EL elements that emit red light, green light, and blue light are combined.

The storage capacitance C is provided such that one end of the capacitor 9 is electrically connected to the source electrode 10s of the selection TFT element 10 and the gate electrode 11g of the drive TFT element 11, and the other end of the capacitor 9 is electrically connected to the source electrode 11s of the drive TFT element 11.

The two TFT elements 10 and 11 use an oxide semiconductor such as an oxide of indium (In)-tin (Sn)-zinc (Zn) (InSnZnO). The oxide semiconductor may be an oxide containing at least one metal element such as In, gallium (Ga), Zn, Sn, or Al, or may be polycrystalline silicon, amorphous silicon, or an organic semiconductor. The gate insulating layer 20 uses, for example, silicon oxide (SiO _x ).

The selection TFT elements 10 are arranged side by side on the first substrate 12A as second switching elements. The selection TFT elements 10 are arranged such that the gate electrode 10g is electrically connected to the scanning line 5, the drain electrode 10d is electrically connected to the signal line 6, and the source electrode 10s is electrically connected to the gate electrode 11g of the drive TFT element 11 and one end of the storage capacitance C (capacitor 9).

The driving TFT elements 11 are arranged side by side on the second substrate 12B as first switching elements. On the second substrate 12B, a gate insulating layer 20 and an interlayer insulating layer 16 are laminated in order, similar to the first substrate 12A.

The driving TFT element 11 is provided with a gate electrode 10g electrically connected to the source electrode 10s of the selection TFT element 10 and the storage capacitance C (one end of the capacitor 9), a drain electrode 11d electrically connected to the power line 7, and a source electrode 11s electrically connected to the pixel electrode 13 and the other end of the storage capacitance C (capacitor 9).

As shown in FIG. 1, the multiple scanning lines 5 are electrically connected to a scanning line driving circuit (gate driver) 31 including, for example, a shift register and a level shifter. The gate driver 31 sequentially supplies scanning signals to the multiple scanning lines 5, and switches the driving of the selection TFT elements 10 in response to the scanning signals.

The multiple signal lines 6 are electrically connected to a signal line driving circuit (data driver) 32 that includes, for example, a shift register, a level shifter, a video line, and an analog switch. The data driver 32 supplies image data to the multiple signal lines 6.

In the display panel 2A, the potential (image data) of the signal line 6 is held in the holding capacitance C via the selection TFT element 10 by the switching operation of the selection TFT element 10. In addition, depending on the potential of the holding capacitance C, a driving current flows from the power line 7 to the organic EL element 8 via the driving TFT element 11. This makes it possible to cause the organic EL element 8 to emit light (light up).

In the pixel circuit substrate 4 of this embodiment, the other surface (rear surface) of the first substrate 12A and one surface (front surface) of the second substrate 12B face each other, and the first substrate 12A and the second substrate 12B are electrically connected via the connection portion 22.

Specifically, this connection portion 22 electrically connects between the gate electrode 10g of the driving TFT element 11 provided on the first substrate 12A side and the source electrode 10s of the selection TFT element 10 provided on the second substrate 12B side.

The gate electrode 11g of the driving TFT element 11 is disposed on the surface of the first substrate 12A and is electrically connected to a first connection wiring 24 disposed on the back surface of the first substrate 12A via a first contact plug 23 disposed through the first substrate 12.

The first contact plug 23 is formed by embedding a coating type conductive material, such as silver (Ag) paste, in a contact hole penetrating the first substrate 12A. The first connection wiring 24 is formed integrally with the first contact plug 23 using the same conductive material as the first contact plug 23.

The source electrode 10s of the selection TFT element 10 is disposed on the gate insulating layer 20 of the second substrate 12B, and is electrically connected to a second connection wiring 26 disposed on the interlayer insulating layer 16 via a second contact plug 25 disposed through the interlayer insulating layer 16.

The second contact plug 25 is formed by embedding the second contact plug 25 in a contact hole penetrating the interlayer insulating layer 16 using the same conductive material as the first contact plug 23. The second connection wiring 26 is formed integrally with the second contact plug 25 using the same conductive material as the first contact plug 23.

The connection portion 22 electrically connects the first connection wiring 24 and the second connection wiring 26. The connection portion 22 is preferably made of a coating type conductive material such as silver (Ag) paste, and can be formed by coating using a dispenser or the like.

In the display device 1A of this embodiment, the display panel 2A described above has a pixel circuit substrate 4 in which a first substrate 12A on which an organic EL element 8 and a driving TFT element 11 are provided and a second substrate 12B on which a selection TFT element 10 is provided are laminated. In addition, the driving TFT element 11 on the first substrate 12A side constituting the pixel circuit substrate 4 and the selection TFT element 10 on the second substrate 12B side are electrically connected via a connection portion 22.

As a result, in the display device 1A of this embodiment, it is possible to reduce the area of each pixel circuit 3 (pixel P) arranged side by side on the surface of the pixel circuit substrate 4, thereby achieving high definition for the display panel 2A.

[Display Device Manufacturing Method]
Next, a method for manufacturing the display device 1A will be described with reference to FIGS.
5 to 9 are cross-sectional views for explaining the process of manufacturing the display panel 2A.

In the method for manufacturing the display device 1A of this embodiment, when manufacturing the display panel 2A, first, as shown in FIG. 5, the first substrate 12A and the second substrate 12B are manufactured using the same mother substrate 200.

Specifically, a mother substrate 200 that will become the first substrate 12A and the second substrate 12B formed in a film shape on the surface of the first glass substrate 101 is prepared. Then, in the process of fabricating the pixel circuit substrate 4, the front side of the first substrate 12A and the second substrate 12B are formed on one surface (front surface) of the mother substrate 200.

That is, in the process of producing the pixel circuit substrate 4, the above-mentioned scanning lines 5, signal lines 6, power supply lines 7, and GND lines 19, contact plugs 21a, contact electrodes 21b, and contact plugs 21c, the organic EL elements 8 (pixel electrodes 13, organic functional layers 14, and common electrodes 15) constituting the pixel circuits 3, the capacitors 9, the driving TFT elements 11 including the gate insulating layer 20, the interlayer insulating layer 16, the bank layers 17, and the protective layer 18 are formed on one side (front surface) of the first substrate 12A.

These formation processes can be performed using conventionally known film formation processes, photolithography processes, and the like, and there are no particular limitations on the formation method.

On the other hand, the selection TFT element 10 including the gate insulating layer 20 described above and the interlayer insulating layer 16 are formed on one surface (front surface) of the second substrate 12B. This forms the front side of the first substrate 12A and the second substrate 12B on one surface (front surface) of the mother substrate 200.

A contact hole penetrating the interlayer insulating layer 16 is formed at the position where the second contact plug 25 is to be formed. Then, a coating type conductive material such as silver (Ag) paste is applied using a dispenser, and then patterned into a predetermined shape. This results in the second contact plug 25 embedded in the contact hole and the second connection wiring 26 arranged on the surface of the interlayer insulating layer 16 being integrally formed.

Next, as shown in FIG. 6, a second glass substrate 103 is attached to the top layer of the mother substrate 200 via an adhesive layer 102, and then laser light (not shown) is irradiated from the first glass substrate 101 side toward the mother substrate 200. At this time, the laser light passes through the first glass substrate 101 and is absorbed by the mother substrate 200, causing a part of the plastic film near the interface with the first glass substrate 101 to evaporate due to heat. This allows the first glass substrate 101 to be peeled off from the other surface (rear surface) of the mother substrate 200.

Next, as shown in FIG. 7, a contact hole 104 is formed through the mother substrate 200 (first substrate 12A) at the position where the first contact plug 23 is to be formed.

Next, as shown in FIG. 8, a coating-type conductive material such as silver (Ag) paste is applied using a dispenser and then patterned into a predetermined shape. This results in the formation of a first contact plug 23 embedded in the contact hole 104 and a first connection wiring 24 disposed on the rear surface of the mother substrate 200 (first substrate 12A).

Next, as shown in FIG. 9, the second glass substrate 103 is removed together with the adhesive layer 102 from the mother substrate 200, and then the mother substrate 200 is cut between the first substrate 12A and the second substrate 12B.

Next, with the other surface (rear surface) of the first substrate 12A facing one surface (front surface) of the second substrate 12B, the first substrate 12A and the second substrate 12B are electrically connected via the connection portion 22. At this time, the connection portion 22 electrically connects the first connection wiring 24 and the second connection wiring 26. This makes it possible to fabricate the display panel 2A.

In the manufacturing method of the display device 1A of this embodiment, it is possible to simultaneously manufacture the first substrate 12A on which the above-mentioned organic EL element 8 and driving TFT element 11 are provided, and the second substrate 12B on which the selection TFT element 10 is provided. This makes it possible to reduce the manufacturing cost of the display panel 2A.

In this embodiment, the first substrate 12A and the second substrate 12B are fabricated simultaneously using the mother substrate 200. However, it is also possible to fabricate the first substrate 12A and the second substrate 12B simultaneously using different mother substrates.

Second Embodiment
[Display Device]
Next, as a second embodiment of the present invention, a display device 1B shown in, for example, FIGS. 10 and 11 will be described.

Note that FIG. 10 is a cross-sectional view of a main part of the display panel 2B of the display device 1B in one direction. FIG. 11 is a cross-sectional view of a main part of the display panel 2B in another direction. In the following explanation, the same parts as those of the display device 1A will not be described and will be denoted by the same reference numerals in the drawings.

As shown in Figs. 10 and 11, the display device 1B of this embodiment includes a display panel 2B including a display area E in which a plurality of pixels P are arranged side by side within a plane. The display panel 2B differs from the display panel 2A in the layered structure of the pixel circuit substrate 4, the first substrate 12A on which the organic EL element 8 and the driving TFT element 11 are provided, and the second substrate 12B on which the selection TFT element 10 is provided.

In other words, in the pixel circuit substrate 4 of this embodiment, the other surface (rear surface) of the first substrate 12A faces the other surface (rear surface) of the second substrate 12B, and the first substrate 12A and the second substrate 12B are electrically connected via the connection portion 22.

Specifically, this connection portion 22 electrically connects between the gate electrode 10g of the driving TFT element 11 provided on the first substrate 12A side and the source electrode 10s of the selection TFT element 10 provided on the second substrate 12B side.

The gate electrode 10g of the driving TFT element 11 is disposed on the surface of the first substrate 12A and is electrically connected to a first contact plug 23 disposed through the first substrate 12.

On the other hand, the source electrode 10s of the selection TFT element 10 is disposed on the gate insulating layer 20 of the second substrate 12B and is electrically connected to a second contact plug 25 disposed to penetrate the second substrate 12B. The second contact plug 25 is formed by filling a contact hole penetrating the second substrate 12B with the same conductive material as the first contact plug 23.

The connection portion 22 electrically connects the first contact plug 23 and the second contact plug 25.

In the display device 1B of this embodiment, the display panel 2B described above has a pixel circuit substrate 4 in which a first substrate 12A on which an organic EL element 8 and a driving TFT element 11 are provided and a second substrate 12B on which a selection TFT element 10 is provided are stacked. In addition, the driving TFT element 11 on the first substrate 12A side constituting the pixel circuit substrate 4 and the selection TFT element 10 on the second substrate 12B side are electrically connected via a connection portion 22.

As a result, in the display device 1B of this embodiment, it is possible to reduce the area of each pixel circuit 3 (pixel P) arranged side by side on the surface of the pixel circuit substrate 4, thereby achieving high definition in the display panel 2B.

[Display Device Manufacturing Method]
Next, a method for manufacturing the display device 1B will be described with reference to FIGS.
12 to 16 are cross-sectional views for explaining the steps of manufacturing the display panel 2B. In the following explanation, steps similar to those in the manufacturing method of the display device 1A will be described using the same reference numerals, although the drawings will be omitted.

In the method for manufacturing the display device 1B of this embodiment, when manufacturing the display panel 2B, first, as shown in FIG. 12, the first substrate 12A and the second substrate 12B are manufactured using the same mother substrate 200.

Specifically, a mother substrate 200 that will become the first substrate 12A and the second substrate 12B formed in a film shape on the surface of the first glass substrate 101 is prepared. Then, in the process of fabricating the pixel circuit substrate 4, the front side of the first substrate 12A and the second substrate 12B are formed on one surface (front surface) of the mother substrate 200.

That is, in the process of producing the pixel circuit substrate 4, the above-mentioned scanning lines 5, signal lines 6, power supply lines 7, and GND lines 19, contact plugs 21a, contact electrodes 21b, and contact plugs 21c, the organic EL elements 8 (pixel electrodes 13, organic functional layers 14, and common electrodes 15) constituting the pixel circuits 3, the capacitors 9, the driving TFT elements 11 including the gate insulating layer 20, the interlayer insulating layer 16, the bank layers 17, and the protective layer 18 are formed on one side (front surface) of the first substrate 12A.

These formation processes can be performed using conventionally known film formation processes, photolithography processes, and the like, and there are no particular limitations on the formation method.

On the other hand, the selection TFT element 10 including the gate insulating layer 20 described above and the interlayer insulating layer 16 are formed on one surface (front surface) of the second substrate 12B. This forms the front side of the first substrate 12A and the second substrate 12B on one surface (front surface) of the mother substrate 200.

Next, as shown in FIG. 13, a second glass substrate 103 is attached to the top layer of the mother substrate 200 via an adhesive layer 102, and then laser light (not shown) is irradiated from the first glass substrate 101 side toward the mother substrate 200. At this time, the laser light passes through the first glass substrate 101 and is absorbed by the mother substrate 200, causing a part of the plastic film near the interface with the first glass substrate 101 to evaporate due to heat. This allows the first glass substrate 101 to be peeled off from the other surface (rear surface) of the mother substrate 200.

Next, as shown in FIG. 14, contact holes 104 are formed through the mother substrate 200 (first substrate 12A) at the positions where the first contact plugs 23 and the second contact plugs 25 are to be formed.

Next, as shown in FIG. 15, a coating-type conductive material such as silver (Ag) paste is applied using a dispenser and then patterned into a predetermined shape. This forms the first contact plug 23 and the second contact plug 25 embedded in the contact hole 104.

Next, as shown in FIG. 16, the second glass substrate 103 is removed together with the adhesive layer 102 from the mother substrate 200, and then the mother substrate 200 is cut between the first substrate 12A and the second substrate 12B.

Next, with the other surface (rear surface) of the first substrate 12A facing the other surface (rear surface) of the second substrate 12B, the first substrate 12A and the second substrate 12B are electrically connected via the connection portion 22. At this time, the connection portion 22 electrically connects the first contact plug 23 and the second contact plug 25. This makes it possible to fabricate the display panel 2B.

In the manufacturing method of the display device 1B of this embodiment, it is possible to simultaneously manufacture the first substrate 12A on which the above-mentioned organic EL element 8 and driving TFT element 11 are provided, and the second substrate 12B on which the selection TFT element 10 is provided. This makes it possible to reduce the manufacturing cost of the display panel 2B.

In this embodiment, the first substrate 12A and the second substrate 12B are fabricated simultaneously using the mother substrate 200. However, it is also possible to fabricate the first substrate 12A and the second substrate 12B simultaneously using different mother substrates.

Third Embodiment
[Display Device]
Next, as a third embodiment of the present invention, a display device 1C shown in, for example, FIGS. 17 and 18 will be described.

Note that FIG. 17 is a cross-sectional view of a main portion of a display panel 2C provided in a display device 1C, taken along one direction. FIG. 18 is a cross-sectional view of a main portion of a display panel 2C, taken along another direction. In the following explanation, the same parts as those in the display device 1A will not be described and will be denoted by the same reference numerals in the drawings.

The display device 1C of this embodiment includes a display panel 2C including a display area E in which a plurality of pixels P are arranged side by side within a plane, as shown in Figs. 17 and 18. In addition to the configuration of the pixel circuit board 4, the display panel 2C has a structure in which at least one circuit board (one drive circuit board 40 in this embodiment) is laminated on the side (rear side) of the second substrate 12B opposite the side (front side) facing the first substrate 12A.

The drive circuit board 40 has a configuration in which a plurality of gate driver TFT elements 41 that constitute the gate driver 31 are arranged side by side on one surface (front surface) of the third substrate 12C.

The third substrate 12C is the same as the first substrate 12A and the second substrate 12B. The gate driver TFT element 41 is the same as the two TFT elements 10 and 11. In addition, a gate insulating layer 20 and an interlayer insulating layer 16 are laminated in this order on the front surface side of the third substrate 12C.

In addition, a plurality of third connection wirings 42 are arranged in a line on the front surface side of the third substrate 12C, for each line row corresponding to each of the plurality of scanning lines 5. The plurality of third connection wirings 42 are electrically connected to the gate driver 31 (the plurality of gate driver TFT elements 41). The third connection wirings 42 are formed into a linear pattern using a conductive material such as copper, aluminum, molybdenum, or chromium.

The display panel 2C has the back surface of the pixel circuit board 4 (second board 12B) facing the front surface of the drive circuit board 40 (third board 12C), and the second board 12B and the third board 12C are electrically connected via the connection part 43.

Specifically, this connection portion 43 electrically connects between the gate electrode 10g of the selection TFT element 10 provided on the second substrate 12B side and the third connection wiring 42 provided on the third substrate 12C side.

The gate electrode 10g of the selection TFT element 10 is disposed on the surface of the second substrate 12B and is electrically connected to a third contact plug 27 disposed to penetrate the second substrate 12B. The third contact plug 27 is formed by filling a contact hole penetrating the second substrate 12B with a coating type conductive material such as silver (Ag) paste.

The connection portion 43 electrically connects the third contact plug 27 and the third connection wiring 42.

In the display device 1C of this embodiment, the display panel 2C described above has a pixel circuit substrate 4 in which a first substrate 12A on which an organic EL element 8 and a driving TFT element 11 are provided and a second substrate 12B on which a selection TFT element 10 is provided are stacked. In addition, the driving TFT element 11 on the first substrate 12A side constituting the pixel circuit substrate 4 and the selection TFT element 10 on the second substrate 12B side are electrically connected via a connection portion 22.

As a result, in the display device 1C of this embodiment, it is possible to reduce the area of each pixel circuit 3 (pixel P) arranged side by side on the surface of the pixel circuit substrate 4, thereby achieving high definition in the display panel 2C.

In addition, in the display device 1C of this embodiment, the above-mentioned display panel 2C has a structure in which the pixel circuit board 4 and the drive circuit board 40 are stacked. As a result, in the display device 1C of this embodiment, it is possible to realize a smaller display panel 2C than when the pixel circuit board 4 and the drive circuit board 40 are arranged side by side in a plane.

In the display device 1C, the drive circuit board 40 is stacked on the opposite side (rear side) of the second substrate 12B from the side (front side) facing the first substrate 12A. The circuit board may also be configured to include a correction circuit board having a TFT element for correcting characteristic fluctuations and variations over time of the organic EL element 8. The circuit board is not limited to one layer, and may be two or more layers.

[Display Device Manufacturing Method]
Next, a method for manufacturing the display device 1C will be described with reference to FIGS.
19 to 23 are cross-sectional views for explaining the process of manufacturing the display panel 2C.

In the method of manufacturing the display device 1C of this embodiment, when manufacturing the display panel 2C, first, as shown in FIG. 19, the first substrate 12A, the second substrate 12B, and the third substrate 12C are manufactured using the same mother substrate 200.

Specifically, a mother substrate 200 is prepared which will become the first substrate 12A, the second substrate 12B, and the third substrate 12C formed in a film shape on the surface of the first glass substrate 101. Then, in the process of fabricating the pixel circuit substrate 4, the surface sides of the first substrate 12A and the second substrate 12B are formed on one surface (front surface) of the mother substrate 200. Also, in the process of fabricating the drive circuit substrate 40, the surface side of the third substrate 12C is formed on one surface (front surface) of the mother substrate 200.

That is, in the process of producing the pixel circuit substrate 4, the above-mentioned scanning lines 5, signal lines 6, power supply lines 7, and GND lines 19, contact plugs 21a, contact electrodes 21b, and contact plugs 21c, the organic EL elements 8 (pixel electrodes 13, organic functional layers 14, and common electrodes 15) constituting the pixel circuits 3, the capacitors 9, the driving TFT elements 11 including the gate insulating layer 20, the interlayer insulating layer 16, the bank layers 17, and the protective layer 18 are formed on one side (front surface) of the first substrate 12A.

These formation processes can be performed using conventionally known film formation processes, photolithography processes, and the like, and there are no particular limitations on the formation method.

On the other hand, the selection TFT element 10 including the gate insulating layer 20 described above and the interlayer insulating layer 16 are formed on one surface (front surface) of the second substrate 12B. This forms the front side of the first substrate 12A and the second substrate 12B on one surface (front surface) of the mother substrate 200.

A contact hole penetrating the interlayer insulating layer 16 is formed at the position where the second contact plug 25 is to be formed. Then, a coating type conductive material such as silver (Ag) paste is applied using a dispenser, and then patterned into a predetermined shape. This results in the second contact plug 25 embedded in the contact hole and the second connection wiring 26 arranged on the surface of the interlayer insulating layer 16 being integrally formed.

Meanwhile, in the process of producing the drive circuit substrate 40, the gate driver TFT element 41 and the third connection wiring 42 are formed at the same time as the selection TFT element 10 and the drive TFT element 11 including the gate insulating layer 20 of the pixel circuit substrate 4. In addition, an interlayer insulating layer 16 is formed to cover the selection TFT element 10, the drive TFT element 11, and the gate driver TFT element 41. This forms the front side of the drive circuit substrate 40 on the surface of the mother substrate 200.

Next, as shown in FIG. 20, a second glass substrate 103 is attached to the top layer of the mother substrate 200 via an adhesive layer 102, and then laser light (not shown) is irradiated from the first glass substrate 101 side toward the mother substrate 200. At this time, the laser light passes through the first glass substrate 101 and is absorbed by the mother substrate 200, causing a part of the plastic film near the interface with the first glass substrate 101 to evaporate due to heat. This allows the first glass substrate 101 to be peeled off from the other surface (rear surface) of the mother substrate 200.

Next, as shown in FIG. 21, contact holes 104 are formed through the mother substrate 200 (first substrate 12A) at the positions where the first contact plug 23 and the third contact plug 27 are to be formed.

Next, as shown in FIG. 22, a coating-type conductive material such as silver (Ag) paste is applied using a dispenser and then patterned into a predetermined shape. This results in the first contact plug 23 and the third contact plug 27 embedded in the contact hole 104 being integrally formed with the first connection wiring 24 disposed on the rear surface of the mother substrate 200 (first substrate 12A).

Next, as shown in FIG. 23, the second glass substrate 103 is removed together with the adhesive layer 102 from the mother substrate 200, and then the mother substrate 200 is cut between the first substrate 12A, the second substrate 12B, and the third substrate 12C.

Next, with the other surface (rear surface) of the first substrate 12A facing one surface (front surface) of the second substrate 12B, the first substrate 12A and the second substrate 12B are electrically connected via the connection portion 22. At this time, the connection portion 22 electrically connects the first connection wiring 24 and the second connection wiring 26.

In addition, with the other surface (rear surface) of the second substrate 12B facing one surface (front surface) of the third substrate 12C, the second substrate 12B and the third substrate 12C are electrically connected via the connection portion 43. At this time, the connection portion 43 electrically connects between the third contact plug 27 and the third connection wiring 42. This makes it possible to fabricate the display panel 2C.

In the manufacturing method of the display device 1C of this embodiment, it is possible to simultaneously manufacture the first substrate 12A on which the above-mentioned organic EL element 8 and driving TFT element 11 are provided, the second substrate 12B on which the selection TFT element 10 is provided, and the third substrate 12C on which the gate driver TFT element 41 (gate driver 31) is provided. This makes it possible to reduce the manufacturing cost of the display panel 2C.

In this embodiment, the first substrate 12A, the second substrate 12B, and the third substrate 12C are fabricated simultaneously using the mother substrate 200. However, it is also possible to fabricate the first substrate 12A, the second substrate 12B, and the third substrate 12C simultaneously using different mother substrates.

The present invention is not necessarily limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, the present invention is applied to the above-mentioned organic EL display, but the light-emitting element is not necessarily limited to an organic EL element, and may be an LED element such as a micro LED, or a light-emitting element such as a quantum dot. The present invention can also be applied to a liquid crystal display or the like.

The present invention is not limited to the display device described above, but can also be used in electronic devices equipped with image sensors or sensors instead of light-emitting elements, making it possible to perform high-definition imaging and high-sensitivity sensing by adopting a similar structure.

1A, 1B, 1C... Display device 2A, 2B, 2C... Display panel 3... Pixel circuit 4... Pixel circuit board 5... Scanning line 6... Signal line 7... Power line 8... Organic EL element (light-emitting element) 9... Capacitor 10... Selection TFT element (second switching element) 11... Driving TFT element (first switching element) 12A... First substrate 12A... First substrate 12B... Second substrate 12C... Third substrate 13... Pixel electrode 14... Organic functional layer 15... Common electrode 16... Interlayer insulating layer 17... Bank layer 18... Protective layer 19... GND line 20... Gate insulating layer 22... Connection portion 23... First contact plug 24... First connection wiring 25... Second contact plug 26... Second connection wiring 27... Third contact plug 31: Scanning line driving circuit (gate driver) 32: Signal line driving circuit (data driver) 40: Driving circuit board 41: TFT element for gate driver 42: Third connection wiring 43: Connection section 200: Mother substrate C: Storage capacitor P: Pixel Pu: Pixel unit E: Display area

Claims (7)

A display panel including a display area in which a plurality of pixels are arranged in a plane,
the display panel includes a pixel circuit substrate on which pixel circuits constituting the pixels are provided,
the pixel circuit includes a light-emitting element, and a first switching element and a second switching element that switch the lighting of the light-emitting element;
the pixel circuit substrate has a structure in which a first substrate on which the light-emitting element and the first switching element are provided and a second substrate on which the second switching element is provided are laminated, and the first substrate and the second substrate are electrically connected to each other via a connection portion;
the first switching element is disposed on one surface side of the first substrate, and is electrically connected to a first connection wiring disposed on the other surface side of the first substrate via a first contact plug disposed to penetrate the first substrate;
the first connection wiring is formed integrally with the first contact plug by using the same conductive material as the first contact plug;
the second switching element is disposed on one surface side of the second substrate, and is electrically connected to a second connection wiring disposed on the interlayer insulating layer via a second contact plug disposed to penetrate the interlayer insulating layer covering the one surface side of the second substrate,
the second connection wiring is formed integrally with the second contact plug by using the same conductive material as the second contact plug;
A display device characterized in that the first connection wiring and the second connection wiring are electrically connected via the connection portion while the other surface of the first substrate and one surface of the second substrate are opposed to each other. A display panel including a display area in which a plurality of pixels are arranged in a plane,
the display panel includes a pixel circuit substrate on which pixel circuits constituting the pixels are provided,
the pixel circuit includes a light-emitting element, and a first switching element and a second switching element that switch the lighting of the light-emitting element;
the pixel circuit substrate has a structure in which a first substrate on which the light-emitting element and the first switching element are provided and a second substrate on which the second switching element is provided are laminated, and the first substrate and the second substrate are electrically connected to each other via a connection portion;
the first switching element is disposed on one surface side of the first substrate and is electrically connected to a first contact plug disposed to penetrate the first substrate;
the second switching element is disposed on one surface side of the second substrate and is electrically connected to a second contact plug disposed to penetrate the second substrate;
the first contact plug and the second contact plug are formed using the same conductive material;
A display device characterized in that the first contact plug and the second contact plug are electrically connected via the connection portion with the other surface of the first substrate facing the other surface of the second substrate. The display device according to claim 1 or 2, characterized in that the connection portion is formed using the same conductive material as the first contact plug and the second contact plug. The display device according to any one of claims 1 to 3, characterized in that at least one circuit board is laminated on the surface of the second substrate opposite the surface facing the first substrate. The display device according to claim 4, characterized in that the circuit board includes a drive circuit board on which a drive circuit for driving the pixel circuits is provided. A method for manufacturing a display device including a display panel including a display region in which a plurality of pixels are arranged in a plane, comprising the steps of:
When manufacturing the display panel, a step of manufacturing a pixel circuit substrate on which a pixel circuit constituting the pixel is provided is included,
the pixel circuit includes a light-emitting element, and a first switching element and a second switching element that switch the lighting of the light-emitting element;
In the step of manufacturing the pixel circuit substrate, when a first substrate on which the light emitting element and the first switching element are formed and a second substrate on which the second switching element is formed are manufactured using a same mother substrate,
forming the first switching element, the second switching element, and an interlayer insulating layer on one surface side of the mother substrate;
a step of forming a contact hole penetrating the interlayer insulating layer at a position where the second switching element is to be formed, and then applying a conductive material onto the interlayer insulating layer and patterning the conductive material into a predetermined shape to integrally form a second contact plug embedded in the contact hole and a second connection wiring disposed on a surface of the interlayer insulating layer;
forming a contact hole penetrating the mother substrate at a position where the first switching element is to be formed, and then applying a conductive material to the other surface side of the mother substrate and patterning the conductive material into a predetermined shape to integrally form a first contact plug embedded in the contact hole and a first connection wiring disposed on the other surface side of the mother substrate;
After cutting the mother substrate into the first substrate and the second substrate,
A method for manufacturing a display device, characterized in that the first connection wiring and the second connection wiring are electrically connected via a connection portion while the other surface of the first substrate and one surface of the second substrate are opposed to each other. A method for manufacturing a display device including a display panel including a display region in which a plurality of pixels are arranged in a plane, comprising the steps of:
When manufacturing the display panel, a step of manufacturing a pixel circuit substrate on which a pixel circuit constituting the pixel is provided is included,
the pixel circuit includes a light-emitting element, and a first switching element and a second switching element that switch the lighting of the light-emitting element;
In the step of manufacturing the pixel circuit substrate, when a first substrate on which the light emitting element and the first switching element are formed and a second substrate on which the second switching element is formed are manufactured using a same mother substrate,
forming the first switching element and the second switching element on one surface side of the mother substrate;
forming contact holes penetrating the mother substrate at positions where the first switching element and the second switching element are to be formed, and then applying a conductive material to the other surface side of the mother substrate and patterning the conductive material into a predetermined shape to form a first contact plug and a second contact plug embedded in the contact holes;
After cutting the mother substrate into the first substrate and the second substrate,
A method for manufacturing a display device, characterized in that the first contact plug and the second contact plug are electrically connected via a connection portion while the other surface of the first substrate and the other surface of the second substrate are opposed to each other.

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