JP2012064421A - Light-emitting device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To seal a light-emitting device well.SOLUTION: In an electroluminescence (EL) panel 1, a substrate 10 of which a light-emitting region R including a plurality of arranged EL elements 8 is provided on the upper surface, and a sealing substrate 22 that faces the upper surface side of the substrate 10 are adhered to each other by a sealing member 15; and the light-emitting region R is sealed between the substrate 10 and the sealing substrate 22. The substrate 10 and the sealing substrate 22 are adhered to each other by the sealing member 15 in which a second adhesive surface 152 having relatively strong adhesive force faces the sealing substrate 22 side, and a first adhesive surface 151 having relatively small adhesive force faces the upper surface side of the substrate 10.

Description

  The present invention relates to a light emitting device and a method for manufacturing the light emitting device.

In recent years, EL display devices, which are light emitting devices using EL (Electro Luminescence) elements, have been used. The EL display device includes a plurality of EL elements, and the EL display device displays various images and videos by an active matrix system that controls a current supplied to each EL element.
In order to stabilize the light emitting display performance of this EL display device for a long period of time, a technology for sealing the EL element between a pair of substrates with a sealing material is known so that the EL element is not deteriorated by moisture or oxygen. (For example, refer to Patent Document 1).

JP 2009-117178 A

However, in the case of the above-mentioned Patent Document 1, the surface of one substrate is uneven due to the provision of EL elements, whereas the surface of the other substrate is flat and has no undulations. The attached sealing material adheres strongly to one substrate side having a large contact area.
As described above, if there is a difference in the adhesive strength of the sealing material to both substrates, peeling from the substrate side having weak adhesive strength is likely to occur, so that when the EL display device is stressed, the substrate is peeled off and sealed. There has been a problem that the structure has a problem.

  An object of the present invention is to satisfactorily seal a light emitting device.

The light emitting device of the present invention is
A first substrate having a plurality of pixels each provided with a light-emitting element and having an uneven top surface;
A second substrate having a facing surface facing the top surface of the first substrate;
A sealing material for bonding the first substrate and the second substrate;
With
The sealing material has a first bonding surface bonded to the upper surface of the first substrate and a second bonding surface bonded to the facing surface of the second substrate, and bonding the first bonding surface The adhesive force of the second adhesive surface is stronger than the force.
Preferably, the unevenness is formed by a partition wall surrounding the plurality of pixels.
Preferably, the sealing material has a two-layer structure including a weak adhesive layer having the first adhesive surface and a strong adhesive layer having the second adhesive surface, and the stronger the adhesive than the weak adhesive layer. The concentration of the adhesive component contained in the adhesive layer is higher.
Preferably, the sealing material has a two-layer structure including a weak adhesive layer having the first adhesive surface and a strong adhesive layer having the second adhesive surface, and the strong adhesive layer has the weak adhesive layer. An adhesive component having higher adhesive strength than the adhesive layer is contained.
Preferably, a frame-shaped sealing material is provided along the outer peripheral side of the first substrate and the second substrate, and the periphery of the sealing material is covered with the sealing material.

The manufacturing method of the light emitting device of the present invention is as follows:
Forming a plurality of pixels each having a light emitting element on one surface of the first substrate;
The sealing material is formed so that the second adhesive surface of the sealing material having a first adhesive surface and a second adhesive surface having a stronger adhesive force than the first adhesive surface is bonded to one surface of the second substrate. And a process of
A step of bonding the first substrate and the second substrate so that the first adhesive of the sealing material is bonded to the one surface of the uneven first substrate. .

  According to the present invention, the light emitting device can be satisfactorily sealed.

It is a top view which shows the arrangement configuration of the pixel of an EL panel. It is a top view which shows schematic structure of EL panel. It is a circuit diagram showing a circuit corresponding to one pixel of an EL panel. It is the top view which showed 1 pixel of EL panel. It is arrow sectional drawing of the surface along the VV line of FIG. It is arrow sectional drawing of the surface along the VI-VI line of FIG. It is sectional drawing which shows the outline of the sealing structure of EL panel. It is explanatory drawing which shows the sealing process of EL panel. It is a schematic sectional drawing which shows the modification of the sealing structure of EL panel. It is a front view which shows an example of the mobile telephone by which EL panel was applied to the display panel. They are the front side perspective view (a) which shows an example of the digital camera with which the EL panel was applied to the display panel, and a rear side perspective view (b). It is a perspective view which shows an example of the personal computer by which EL panel was applied to the display panel.

  Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

  FIG. 1 is a plan view showing an arrangement configuration of a plurality of pixels P in an EL panel 1 that is a light emitting device, and FIG. 2 is a plan view showing a schematic configuration of the EL panel 1.

As shown in FIGS. 1 and 2, the EL panel 1 has a plurality of pixels P arranged in a matrix with a predetermined pattern. The plurality of pixels P includes a red pixel P that emits R (red), a green pixel P that emits G (green), and a blue pixel P that emits B (blue).
In the EL panel 1, a plurality of scanning lines 2 are arranged so as to be substantially parallel to each other along the row direction, and the plurality of signal lines 3 are arranged along the column direction so as to be substantially orthogonal to the scanning lines 2 in plan view. They are arranged so as to be substantially parallel to each other. A voltage supply line 4 is provided along the scanning line 2 between the adjacent scanning lines 2. A range surrounded by these two adjacent scanning lines 2 and two adjacent signal lines 3 corresponds to the pixel P.
Further, the EL panel 1 is provided with a bank 13 as a partition so as to cover the scanning line 2, the signal line 3, and the voltage supply line 4. The banks 13 are provided in a lattice shape, for example, and a plurality of substantially rectangular openings 13 a surrounded by the banks 13 are formed for each pixel P. Predetermined carrier transport layers (a hole injection layer 8b and a light emitting layer 8c described later) are provided in the opening 13a of the bank 13, and become a light emitting element (an EL element 8 described later) in each pixel P. The carrier transport layer is a layer that transports holes or electrons when a voltage is applied. The area where the openings 13 a are arranged in the bank 13 and the pixels P are arranged corresponds to the light emitting area R of the EL panel 1. As described above, the bank 13 is not only provided with the opening 13a for each pixel P, but also covers the signal line 3, extends in the column direction, and is arranged in the column direction as described later. The pixel P may have a stripe-shaped opening that exposes the central portion of each pixel electrode 8a.

  FIG. 3 is a circuit diagram showing a circuit corresponding to one pixel of the EL panel 1 operating in the active matrix driving method.

  As shown in FIG. 3, the EL panel 1 is provided with a scanning line 2, a signal line 3 intersecting with the scanning line 2, and a voltage supply line 4 along the scanning line 2. For each pixel P, a switch transistor 5 that is a thin film transistor, a drive transistor 6 that is a thin film transistor, a capacitor 7, and an EL element 8 are provided.

  In each pixel P, the gate of the switch transistor 5 is connected to the scanning line 2, one of the drain and source of the switch transistor 5 is connected to the signal line 3, and the other of the drain and source of the switch transistor 5 is It is connected to one electrode of the capacitor 7 and the gate of the driving transistor 6. One of the source and drain of the driving transistor 6 is connected to the voltage supply line 4, and the other of the source and drain of the driving transistor 6 is connected to the other electrode of the capacitor 7 and the anode of the EL element 8. Note that the cathodes of the EL elements 8 of all the pixels P are kept at a constant voltage Vcom (for example, grounded).

  Further, around the EL panel 1, each scanning line 2 is connected to a scanning driver, and each voltage supply line 4 is connected to a voltage source that outputs a constant voltage or a voltage driver that outputs a voltage signal as appropriate. Are connected to the data driver, and the EL panel 1 is driven by these drivers by the active matrix driving method. The voltage supply line 4 is supplied with a constant voltage from a voltage source or a voltage signal from a voltage driver.

  Next, the circuit structure of the EL panel 1 and the pixel P will be described with reference to FIGS. Here, FIG. 4 is a plan view corresponding to one pixel P of the EL panel 1, FIG. 5 is a cross-sectional view taken along the line V-V in FIG. 4, and FIG. It is arrow sectional drawing of the surface along the VI-VI line. In FIG. 4, electrodes and wiring are mainly shown.

  As shown in FIG. 4, the switch transistor 5 and the drive transistor 6 are arranged along the signal line 3, the capacitor 7 is disposed in the vicinity of the switch transistor 5, and the EL element 8 is disposed in the vicinity of the drive transistor 6. ing. In each pixel P, a switch transistor 5, a drive transistor 6, a capacitor 7, and an EL element 8 are disposed between the scanning line 2 and the voltage supply line 4.

  As shown in FIGS. 4 to 6, the signal line 3 and the gate electrodes 5 a and 6 a are provided on the substrate 10 which is a transparent first substrate, and the gate insulation of the switch transistor 5 and the drive transistor 6 is provided on one surface of the substrate 10. A first insulating film 11 to be a film is formed. A scanning line 2 and a voltage supply line 4 are formed on the first insulating film 11, and a second insulating film 12 is formed so as to cover the switch transistor 5, the drive transistor 6, the scanning line 2 and the voltage supply line 4. ing. Therefore, the signal line 3 is formed between the first insulating film 11 and the substrate 10, and the scanning line 2 and the voltage supply line 4 are formed between the first insulating film 11 and the second insulating film 12. .

  As shown in FIGS. 4 and 6, the switch transistor 5 is a thin film transistor having an inverted staggered structure. The switch transistor 5 includes a gate electrode 5a, a semiconductor film 5b, a protective insulating film 5d, impurity semiconductor films 5f and 5g, a drain electrode 5h, a source electrode 5i, and the like.

The gate electrode 5 a is formed between the substrate 10 and the first insulating film 11. The gate electrode 5a is preferably formed of a material selected from, for example, a Cr film, an Al film, a Cr / Al laminated film, an AlTi alloy film, or an AlTiNd alloy film. An insulating first insulating film 11 is formed on the gate electrode 5a, and the first insulating film 11 covers the gate electrode 5a.
The first insulating film 11 has, for example, optical transparency and contains silicon nitride or silicon oxide. An intrinsic semiconductor film 5b is formed on the first insulating film 11 at a position corresponding to the gate electrode 5a, and the semiconductor film 5b is opposed to the gate electrode 5a with the first insulating film 11 interposed therebetween.
The semiconductor film 5b is made of, for example, microcrystalline silicon (microcrystalline silicon) or includes microcrystalline silicon and amorphous silicon, and a channel is formed in the semiconductor film 5b. An insulating protective insulating film 5d is formed on the central portion of the semiconductor film 5b. The protective insulating film 5d preferably contains, for example, silicon nitride or silicon oxide.
An impurity semiconductor film 5f is formed on one end portion of the semiconductor film 5b so as to partially overlap the protective insulating film 5d, and the impurity semiconductor film 5g is formed on the other end portion of the semiconductor film 5b. Is partially overlapped with the protective insulating film 5d. The impurity semiconductor films 5f and 5g are formed on both ends of the semiconductor film 5b so as to be separated from each other. Although the impurity semiconductor films 5f and 5g are n-type semiconductors, the present invention is not limited to this, and may be a p-type semiconductor as long as the switch transistor 5 is a p-type transistor.
A drain electrode 5h is formed on the impurity semiconductor film 5f. A source electrode 5i is formed on the impurity semiconductor film 5g. The drain electrode 5h and the source electrode 5i are preferably formed of a material selected from, for example, a Cr film, an Al film, a Cr / Al laminated film, an AlTi alloy film, or an AlTiNd alloy film.
An insulating second insulating film 12 is formed on the protective insulating film 5d, the drain electrode 5h, and the source electrode 5i, and the protective insulating film 5d, the drain electrode 5h, and the source electrode 5i are covered with the second insulating film 12. Has been. The switch transistor 5 is covered with the second insulating film 12. The second insulating film 12 contains, for example, silicon nitride or silicon oxide.

  As shown in FIGS. 4 and 5, the driving transistor 6 is a thin film transistor having an inverted staggered structure. The drive transistor 6 includes a gate electrode 6a, a semiconductor film 6b, a protective insulating film 6d, impurity semiconductor films 6f and 6g, a drain electrode 6h, a source electrode 6i, and the like.

The gate electrode 6a is preferably formed of a material selected from, for example, a Cr film, an Al film, a Cr / Al laminated film, an AlTi alloy film, or an AlTiNd alloy film. It is formed between the first insulating films 11. The gate electrode 6a is covered with a first insulating film 11 containing, for example, silicon nitride or silicon oxide.
An intrinsic semiconductor film 6b in which a channel is formed is provided on the first insulating film 11 at a position corresponding to the gate electrode 6a. The semiconductor film 6b sandwiches the first insulating film 11 therebetween. Opposite to the gate electrode 6a. The semiconductor film 6b is made of, for example, microcrystalline silicon (microcrystalline silicon) or includes microcrystalline silicon and amorphous silicon.
An insulating protective insulating film 6d is formed on the central portion of the semiconductor film 6b. The protective insulating film 6d preferably contains, for example, silicon nitride or silicon oxide.
Further, an impurity semiconductor film 6f is formed so as to partially overlap the protective insulating film 6d on one end portion of the semiconductor film 6b, and the impurity semiconductor film 6g is formed on the other end portion of the semiconductor film 6b. Is partially overlapped with the protective insulating film 6d. The impurity semiconductor films 6f and 6g are formed on both ends of the semiconductor film 6b so as to be separated from each other. The impurity semiconductor films 6f and 6g are n-type semiconductors. However, the impurity semiconductor films 6f and 6g are not limited to this, and may be p-type semiconductors if the driving transistor 6 is a p-type transistor.
A drain electrode 6h is formed on the impurity semiconductor film 6f. A source electrode 6i is formed on the impurity semiconductor film 6g. The drain electrode 6h and the source electrode 6i are preferably formed of a material selected from, for example, a Cr film, an Al film, a Cr / Al laminated film, an AlTi alloy film, or an AlTiNd alloy film.
An insulating second insulating film 12 is formed on the protective insulating film 6d, the drain electrode 6h, and the source electrode 6i, and the protective insulating film 6d, the drain electrode 6h, and the source electrode 6i are covered with the second insulating film 12. Has been. The drive transistor 6 is covered with the second insulating film 12.

  The capacitor 7 is connected between the gate electrode 6 a and the source electrode 6 i of the driving transistor 6. Specifically, the electrode 7 a of the capacitor 7 is connected to the gate electrode 6 a of the drive transistor 6, and the electrode 7 b of the capacitor 7 is connected to the source electrode 6 i of the drive transistor 6. 4 and 6, one electrode 7a of the capacitor 7 is formed between the substrate 10 and the first insulating film 11, and between the first insulating film 11 and the second insulating film 12. The other electrode 7b of the capacitor 7 is formed, and the electrode 7a and the electrode 7b are opposed to each other with the first insulating film 11 as a dielectric interposed therebetween.

Note that the signal line 3, the electrode 7a of the capacitor 7, the gate electrode 5a of the switch transistor 5, and the gate electrode 6a of the drive transistor 6 are made of a conductive film formed on one surface of the substrate 10 by a photolithography method, an etching method, or the like. It is formed in a lump by shape processing.
In addition, the scanning line 2, the voltage supply line 4, the electrode 7 b of the capacitor 7, the drain electrode 5 h and source electrode 5 i of the switch transistor 5, and the drain electrode 6 h and source electrode 6 i of the driving transistor 6 are on the first insulating film 11. The conductive film thus formed is formed by shape processing by a photolithography method, an etching method, or the like.

In the first insulating film 11, a contact hole 11a is formed in a region where the gate electrode 5a and the scanning line 2 overlap, and a contact hole 11b is formed in a region where the drain electrode 5h and the signal line 3 overlap. A contact hole 11c is formed in a region where 6a and the source electrode 5i overlap, and contact plugs 20a to 20c are buried in the contact holes 11a to 11c, respectively. The contact plug 20a electrically connects the gate electrode 5a of the switch transistor 5 and the scanning line 2, the contact plug 20b electrically connects the drain electrode 5h of the switch transistor 5 and the signal line 3, and the contact plug 20c electrically connects the switch transistor. 5 source electrode 5i and capacitor 7 electrode 7a are electrically connected, and source electrode 5i of switch transistor 5 and gate electrode 6a of drive transistor 6 are electrically connected. The scanning line 2 may be in direct contact with the gate electrode 5a, the drain electrode 5h may be in contact with the signal line 3, and the source electrode 5i may be in contact with the gate electrode 6a without using the contact plugs 20a to 20c.
Further, the gate electrode 6a of the driving transistor 6 is integrally connected to the electrode 7a of the capacitor 7, the drain electrode 6h of the driving transistor 6 is integrally connected to the voltage supply line 4, and the source electrode 6i of the driving transistor 6 is connected to the capacitor. 7 is integrally connected to the electrode 7b.

The pixel electrode 8 a is provided on the substrate 10 via the first insulating film 11 and is formed independently for each pixel P. In the case of a bottom emission structure that emits light from the EL element 8 from the pixel electrode 8a side, the pixel electrode 8a is a transparent electrode, for example, tin-doped indium oxide (ITO), zinc-doped indium oxide, indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), zinc oxide (ZnO) or cadmium-tin oxide (CTO). Further, in the case of a top emission structure that emits light from the EL element 8 from the counter electrode 8d side, the pixel electrode 8a has a light-reflective layer as a single layer or an alloy layer such as highly light-reflective aluminum, and the above-described layer as an upper layer. It is preferable to have a laminated structure of transparent electrodes. The pixel electrode 8a partially overlaps the source electrode 6i of the driving transistor 6, and the pixel electrode 8a and the source electrode 6i are connected.
4 and 5, the second insulating film 12 includes the scanning line 2, the signal line 3, the voltage supply line 4, the switch transistor 5, the driving transistor 6, the peripheral edge of the pixel electrode 8a, the capacitor 7 It is formed so as to cover the electrode 7 b and the first insulating film 11. That is, the opening 12a is formed in the second insulating film 12 so that the central portion of each pixel electrode 8a is exposed. Therefore, the second insulating film 12 is formed in a lattice shape in plan view.

  As shown in FIGS. 4 and 5, the EL element 8 includes a pixel electrode 8a serving as an anode, a hole injection layer 8b that is a compound film formed on the pixel electrode 8a, and a hole injection layer 8b. A light emitting layer 8c which is a compound film formed on the light emitting layer 8 and a counter electrode 8d which is a cathode formed on the light emitting layer 8c. The counter electrode 8d is a single electrode common to all the pixels P, and is continuously formed in all the pixels P.

The hole injection layer 8b is a layer made of, for example, PEDOT (poly (ethylenedioxy) thiophene) which is a conductive polymer and PSS (polystyrene sulfonate) which is a dopant, and is a pixel electrode. This is a carrier injection layer that injects holes from 8a toward the light emitting layer 8c.
The light emitting layer 8c includes a material that emits any one of R (red), G (green), and B (blue) for each pixel P. For example, the light emitting layer 8c is a layer made of a polyfluorene light emitting material or a polyphenylene vinylene light emitting material. Thus, light is emitted in association with recombination of electrons supplied from the counter electrode 8d and holes injected from the hole injection layer 8b. For this reason, the pixel P that emits R (red), the pixel P that emits G (green), and the pixel P that emits B (blue) have different light emitting materials for the light emitting layer 8c. Note that the R (red), G (green), and B (blue) pattern of the pixel P is not limited to the lattice pattern, and may be a delta arrangement or a stripe pattern in which the same color pixels are arranged in the vertical direction. May be. In the case of a stripe pattern, the opening 13a of the bank 13 has a stripe shape that exposes central portions of the pixel electrodes 8a of the plurality of pixels P along the column direction.

The counter electrode 8d is formed of a material having a work function lower than that of the pixel electrode 8a. For example, the counter electrode 8d lowers the sheet resistance and the lower layer of a simple substance or an alloy containing at least one of indium, magnesium, calcium, lithium, barium, and rare earth metals. Therefore, it is formed of an upper layer laminate. In the case of a top emission structure that emits light from the EL element 8 from the counter electrode 8d side, the upper layer is a transparent electrode, for example, tin-doped indium oxide (ITO), zinc-doped indium oxide, indium oxide (In ₂ O ₃ ), Tin oxide (SnO ₂ ), zinc oxide (ZnO) or cadmium-tin oxide (CTO), and the light emitted from the EL element 8 is emitted from the pixel electrode 8a side. If it is a bottom emission to be performed, a simple substance such as aluminum having high light reflectivity or an alloy layer is preferable.
The counter electrode 8d is an electrode common to all the pixels P, and covers a bank 13 described later together with a compound film such as the light emitting layer 8c.

As described above, the light emitting layer 8 c serving as a light emitting portion is partitioned for each pixel P by the second insulating film 12 and the bank 13.
In the opening 13 a of the bank 13, a hole injection layer 8 b and a light emitting layer 8 c as a carrier transport layer are stacked on the pixel electrode 8 a. The hole injection layer 8b may be continuously formed so as to straddle the plurality of pixels P. In this case, germanium oxide having a hole injection property is preferable.

Specifically, the bank 13 forms the hole injection layer 8b and the light emitting layer 8b and the light emitting layer 8c in a predetermined region corresponding to the pixel P surrounded by the bank 13 by a wet method. The liquid material in which the material to be 8c is dissolved or dispersed in the solvent functions as a partition wall that prevents the liquid material from flowing out to the adjacent pixel P through the bank 13.
For example, as shown in FIG. 5, the opening end of the opening 13 a of the bank 13 provided on the second insulating film 12 is located inside the opening end of the opening 12 a of the second insulating film 12. Therefore, the bank 13 covers the entire surface of the second insulating film 12. By making the second insulating film 12 wider than the bank 13, the opening 13 a becomes wider than the opening 12 a, and the side surface at the opening end of the opening 12 of the second insulating film 12 is the bank 13. You may make it expose from the opening part 13a.
Then, a liquid containing a material to be the hole injection layer 8b is applied on each pixel electrode 8a surrounded by each opening 13a, and the substrate 10 is heated to dry the liquid to form a film. The resulting compound film becomes the hole injection layer 8b which is the first carrier transport layer.
Further, a liquid material containing a material to be the light emitting layer 8c is applied on each hole injection layer 8b surrounded by each opening 13a, and the whole substrate 10 is heated to dry the liquid material to form a film. The compound film becomes the light emitting layer 8c which is the second carrier transport layer.
A counter electrode 8 d is provided so as to cover the light emitting layer 8 c and the bank 13.

A region where a plurality of EL elements 8 (pixels P) are arranged in accordance with the opening 13 a of the bank 13 is a light emitting region R of the EL panel 1.
In the EL panel 1, in the case of the bottom emission structure, the pixel electrode 8a, the substrate 10 and the first insulating film 11 are transparent, and light emitted from the light emitting layer 8c is transmitted to the pixel electrode 8a, the first insulating film 11 and The light passes through the substrate 10 and is emitted. Therefore, the back surface of the substrate 10 becomes a display surface.
A top emission structure in which the display surface is the opposite side instead of the substrate 10 side may be used. In this case, as described above, the counter electrode 8d is a transparent electrode, the pixel electrode 8a is a reflective electrode, and light emitted from the light emitting layer 8c is transmitted through the counter electrode 8d and emitted.

  Further, as shown in FIGS. 5 to 7, a passivation film 14 that covers the counter electrode 8 d and the bank 13 is provided on the upper surface side of the substrate 10. The passivation film 14 is an insulating protective film and covers the light emitting region R of the EL panel 1 so as to protect it. In the EL panel 1 shown in FIG. 7, the illustration of the first insulating film 11, the second insulating film 12, the switch transistor 5, the driving transistor 6, the pixel electrode 8a and the like on the substrate 10 is omitted. 1 is illustrated in a simplified manner.

Further, as shown in FIGS. 5 to 7, a sealing substrate 22 which is a transparent second substrate is fixed to the arrangement facing the light emitting region R on the upper surface side of the substrate 10 by a sealing material 15.
The sealing material 15 is provided so as to cover the entire surface of the passivation film 14, and covers the light emitting region R via the passivation film 14. The sealing material 15 functions as a part of the protective film so as to supplement the film property of the passivation film 14.
The sealing material 15 fills the space between the sealing substrate 22 and the substrate 10 (passivation film 14) without a cavity, and seals the EL element 8 (light emitting region R) between the sealing substrate 22 and the substrate 10. Yes. That is, the EL element 8 (light emitting region R) is all solid-sealed in a package including the sealing substrate 22, the substrate 10, and the sealing material 15.

In particular, as shown in FIGS. 7 and 8, the sealing material 15 has a weak adhesive layer 15a having a first adhesive surface 151 on the substrate 10 side and a strong adhesive having a second adhesive surface 152 on the sealing substrate 22 side. It consists of the adhesive layer 15b and has a two-layer structure.
For example, the strong adhesive layer 15b is formed of a material having a higher concentration of adhesive component than the weak adhesive layer 15a, and the strong adhesive layer 15b (second adhesive surface 152) is the weak adhesive layer 15a (first adhesive surface). Adhesive strength is stronger than 151). For example, the concentration of the adhesive component of the strong adhesive layer 15b is preferably 1.2 to 2.0 times the concentration of the adhesive component of the weak adhesive layer 15a.

By making the adhesive component contained in the strong adhesive layer 15b and the weak adhesive layer 15a the same substance, the concentration of the adhesive component contained in the strong adhesive layer 15b is made higher than the concentration of the weak adhesive layer 15a. The adhesive strength of the strong adhesive layer 15b (second adhesive surface 152) is not limited to relatively strong.
For example, by making the adhesive components contained in the strong adhesive layer 15b and the weak adhesive layer 15a different from each other, the strong adhesive layer 15b contains an adhesive component having a higher adhesive strength than the weak adhesive layer 15a. You may make it make the adhesive force of the strong contact bonding layer 15b (2nd contact surface 152) relatively strong.

The EL panel 1 is driven as follows to emit light.
In a state where a predetermined level of voltage is applied to all the voltage supply lines 4, the scanning driver sequentially applies voltages to the scanning lines 2, thereby sequentially selecting the scanning lines 2. The switch transistor 5 of each pixel P corresponding to the selected scanning line 2 is turned on.
When each scanning line 2 is selected, if a voltage of a level corresponding to the gradation is applied to all the signal lines 3 by the data driver, the switch of each pixel P corresponding to the selected scanning line 2 Since the transistor 5 is on, the voltage on the signal line 3 is applied to the gate electrode 6 a of the drive transistor 6.
The potential difference between the gate electrode 6a and the source electrode 6i of the drive transistor 6 is determined according to the voltage of the level corresponding to the predetermined gradation applied to the gate electrode 6a of the drive transistor 6, and the drive transistor 6 The magnitude of the drain-source current is determined, and the EL element 8 emits light with brightness according to the drain-source current. Thereafter, when the selection of the scanning line 2 is released, the switch transistor 5 is turned off, so that the charge according to the voltage applied to the gate electrode 6a of the driving transistor 6 is stored in the capacitor 7 and the driving transistor 6 The potential difference between the gate electrode 6a and the source electrode 6i is maintained. For this reason, the driving transistor 6 keeps flowing the drain-source current having the same current value as that at the time of selection, and maintains the luminance of the EL element 8.
That is, the switch transistor 5 switches the voltage applied to the gate electrode 6a of the drive transistor 6 to the voltage of the predetermined gradation level applied to the signal line 3, and the drive transistor 6 is applied to the gate electrode 6a. A drain-source current (drive current) having a current value corresponding to the level of the selected voltage is caused to flow from the voltage supply line 4 toward the EL element 8, and the EL element 8 has a predetermined gradation according to the current value (current density). Make it emit light.
In this way, the EL element 8 emits light and the EL panel 1 emits light by driving and controlling the switch transistor 5 and the drive transistor 6.

  Next, a method for manufacturing the EL panel 1 and a sealing method for sealing the EL element 8 (light emitting region R) between the substrate 10 and the sealing substrate 22 will be described.

As shown in FIG. 8, a light emitting region R in which a plurality of EL elements 8 are arranged is provided on the upper surface of the substrate 10, and a sealing substrate 22 is attached to the upper surface side of the substrate 10 with a sealing material 15. .
The sealing material 15 having a two-layer structure of the weak adhesive layer 15a and the strong adhesive layer 15b is formed by overlapping a weak adhesive sheet that becomes the weak adhesive layer 15a and a strong adhesive sheet that becomes the strong adhesive layer 15b. In addition, when forming a single sealing material 15, the sealing material 15 is molded so that the concentration and type of the adhesive component contained on the front surface side and the adhesive component contained on the back surface side are different. It may be.

First, the second adhesive surface 152 of the strong adhesive layer 15 b of the sealing material 15 is attached to the lower surface of the sealing substrate 22.
Next, the substrate 10 and the sealing substrate 22 are bonded together by the sealing material 15 so that the light emitting region R in the substrate 10 is covered with the first adhesive surface 151 of the weak adhesive layer 15 a of the sealing material 15.

Here, when the first adhesive surface 151 of the sealing material 15 is affixed to the upper surface side of the substrate 10, the first adhesive surface 151 side of the sealing material 15 is in a fluid state, thereby causing the bank 13 or the like. The sealing material 15 can be brought into close contact with the unevenness of the light emitting region R to be performed without a gap.
For example, the weak adhesive layer 15a (first adhesive surface 151 side) of the sealing material 15 affixed to the lower surface of the sealing substrate 22 is melted and brought into contact with the substrate 10 and the passivation film 14, or the sealing substrate 22 is contacted. The weak adhesive layer 15a (the first adhesive surface 151 side) of the sealing material 15 affixed to the lower surface of the substrate is melted while being in contact with the substrate 10 and the passivation film 14, so that there is a gap in the unevenness between the sealing substrate 22 and the substrate 10. The sealing material 15 can be filled without any loss.
Thereafter, the sealing material 15 is solidified by photocuring (for example, ultraviolet curing) or the like to form an all solid-sealed package, and the EL panel 1 can be manufactured as shown in FIG. .

As described above, in the EL panel 1, the EL element 8 (light emitting region R) is covered by the passivation film 14 together with the counter electrode 8 d, and the EL element 8 (light emitting region R) is sealed with the sealing substrate 22, the substrate 10, and the seal. Since all the materials are sealed with the material 15, various gas components entering from the outside of the EL panel 1 do not easily reach the EL element 8, and the EL element 8 is not easily deteriorated by moisture or gas components.
In particular, the bonding force of the strong adhesive layer 15b on the sealing substrate 22 side in the sealing material 15 for bonding the substrate 10 and the sealing substrate 22 is made stronger than that of the weak adhesive layer 15a. The sealing substrate 22 and the sealing substrate 22 are bonded to each other with the same adhesive force, and both the sealing substrate 22 and the substrate 10 are difficult to peel off.
That is, since the upper surface of the substrate 10 has irregularities due to the EL elements 8 and the banks 13, the lower surface of the sealing substrate 22 is flat and has no irregularities. Since the area in contact with the sealing substrate 22 is smaller than the area in contact with the sealing substrate 22, the adhesive force of the strong adhesive layer 15b of the sealing material 15 on the sealing substrate 22 side is increased by the smaller contact area. Thus, the adhesive force between the substrate 10 and the sealing substrate 22 in the EL panel 1 is made equal, and the sealing structure by the substrate 10 and the sealing substrate 22 is stabilized.
Even if stress is applied to the EL panel 1, the sealing substrate 22 and the substrate 10 of the EL panel 1 are not easily peeled off, and the sealing structure of the EL panel 1 is maintained.
Thus, since the EL panel 1 is sealed well, the light emission performance of the EL element 8 is not easily deteriorated, and the light emission display performance of the EL panel 1 becomes stable.

The present invention is not limited to the above embodiment.
For example, as shown in FIG. 9, a frame-shaped sealing material 16 may be provided along the outer peripheral sides of the substrate 10 and the sealing substrate 22, and the periphery of the sealing material 15 may be covered with the sealing material 16.

The EL panel 1 formed and manufactured as described above is used as a display panel for various electronic devices.
For example, the display panel 1a of the mobile phone 200 shown in FIG. 10, the display panel 1b of the digital camera 300 shown in FIGS. 11A and 11B, the display panel 1c of the personal computer 400 shown in FIG. The EL panel 1 can be applied.

  The application of the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention.

1 EL panel (light emitting device)
8 EL elements (light emitting elements)
10 Substrate (first substrate)
14 Passivation film 15 Sealing material 15a Weak adhesion layer 151 First adhesion surface 15b Strong adhesion layer 152 Second adhesion surface 22 Sealing substrate (second substrate)
P pixel R light emitting area

Claims (6)

A first substrate having a plurality of pixels each provided with a light-emitting element and having an uneven top surface;
A second substrate having a facing surface facing the top surface of the first substrate;
A sealing material for bonding the first substrate and the second substrate;
With
The sealing material has a first bonding surface bonded to the upper surface of the first substrate and a second bonding surface bonded to the facing surface of the second substrate, and bonding the first bonding surface A light emitting device characterized in that the adhesive force of the second adhesive surface is stronger than the force.   The light-emitting device according to claim 1, wherein the unevenness is formed by a partition wall that surrounds the plurality of pixels. The sealing material has a two-layer structure including a weak adhesive layer having the first adhesive surface and a strong adhesive layer having the second adhesive surface,
The light emitting device according to claim 1, wherein the concentration of the adhesive component contained in the strong adhesive layer is higher than that in the weak adhesive layer. The sealing material has a two-layer structure including a weak adhesive layer having the first adhesive surface and a strong adhesive layer having the second adhesive surface,
The light emitting device according to claim 1, wherein the strong adhesive layer contains an adhesive component having an adhesive strength higher than that of the weak adhesive layer.   The frame-shaped sealing material along the outer peripheral side of said 1st board | substrate and said 2nd board | substrate is provided, and the circumference | surroundings of the said sealing material are covered with the said sealing material, The any one of Claims 1-4 characterized by the above-mentioned. The light emitting device according to 1. Forming a plurality of pixels each having a light emitting element on one surface of the first substrate;
The sealing material is formed so that the second adhesive surface of the sealing material having a first adhesive surface and a second adhesive surface having a stronger adhesive force than the first adhesive surface is bonded to one surface of the second substrate. And a process of
A step of bonding the first substrate and the second substrate so that the first adhesive of the sealing material is bonded to the one surface of the uneven first substrate. Manufacturing method of light-emitting device.

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