Organic light emitting device, manufacturing method thereof, and display unit

The invention provides an organic light emitting device which can electrically connect an auxiliary wiring and a second electrode without using a mask for pixel coating, a manufacturing method thereof, and a display unit. In organic light emitting devices, for example, a first electrode as an anode, an insulating film, an organic layer including a light emitting layer, and a second electrode as a cathode are layered in this order from a substrate side. The organic layer has a break part on a side face of an auxiliary wiring. The auxiliary wiring and the second electrode are electrically connected through this break part.

RELATED APPLICATION DATA

The present application claims priority to Japanese Application(s) No(s). P2003-328979 filed Sep. 19, 2003, which application(s) is/are incorporated herein by reference to the extent permitted by law.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an organic light emitting device comprising an auxiliary wiring between pixels, a manufacturing method thereof, and a display unit using it.

2. Description of the Related Art

In these years, as one of flat panel displays, an organic light emitting display which uses organic light emitting devices has been noted. The organic light emitting display has characteristics that its visual field angle is wide and its power consumption is low since it is a self-luminous type display. The organic light emitting display is also thought of as a display having sufficient response to high-definition high-speed video signals, and is under development toward the practical use.

As an organic light emitting device, for example, as shown inFIG. 1, an organic light emitting device, wherein a first electrode111, an organic layer112including a light emitting layer, and a second electrode113are sequentially layered on a substrate110is known. In some cases, the second electrode113is electrically connected to an auxiliary wiring113A having a low resistance, in order to prevent variation of luminance in a screen by inhibiting voltage drop (for example, refer to Japanese Unexamined Patent Application Publication No. 2001-195008).

Regarding materials for the organic layer112, there are two kinds of the organic layer112: one is made of a low molecular material; and the other is made of a high molecular material. As a method of forming the organic layer112made of the low molecular material, vacuum deposition method is generally used. When the organic layer112is formed by the vacuum deposition method, as shown inFIG. 2, the auxiliary wiring113A is prevented from being covered with the organic layer112by using a mask for pixel coating120having apertures121corresponding to a position where the organic layer112is to be formed. After that, the second electrode113is formed on almost a whole surface of the substrate110, and thereby, the auxiliary wiring113A and the second electrode113are electrically connected.

However, when a high-definition organic light emitting display is fabricated, it is hard to form the organic layer112precisely due to influence of thermal expansion of the mask for pixel coating120. Further, when particles adhering to the mask for pixel coating120adheres to the organic layer112and the like, short circuit may arise. Therefore, it is desirable to form the organic layer112without using the mask for pixel coating120. In this case, however, the organic layer112is formed on almost a whole surface of the substrate110. This leads to a problem that the auxiliary wiring113A and the second electrode113cannot be electrically connected.

SUMMARY OF THE INVENTION

In light of the foregoing, it is an object of the invention to provide an organic light emitting device in which an auxiliary wiring and a second electrode can be electrically connected without using a mask for pixel coating, a manufacturing method thereof, and a display unit.

The organic light emitting device according to the invention is an organic light emitting device comprising: a first electrode formed on a substrate; an auxiliary wiring formed on the substrate, which is insulated from the first electrode; an organic layer which includes a light emitting layer, which covers at least the first electrode and the auxiliary wiring on the substrate, and which has a break part on a side face of the auxiliary wiring; and a second electrode which covers the organic layer, and which is electrically connected to the auxiliary wiring at the break part of the organic layer. Here, the “side face” of the auxiliary wiring means a face crossing a face which contacts the substrate of the auxiliary wiring.

The method of manufacturing an organic light emitting device according to the invention comprises the steps of: forming a first electrode and an auxiliary wiring insulated from the first electrode on a substrate; forming an organic layer including a light emitting layer on at least the first electrode and the auxiliary wiring, and forming a break part by breaking the organic layer by a step of a side face of the auxiliary wiring; and forming a second electrode on the organic layer, and electrically connecting the second electrode and the auxiliary wiring at the break part of the organic layer.

The display unit according to the invention is a display unit having a plurality of organic light emitting devices on a substrate, wherein the organic light emitting device is provided with a first electrode formed on the substrate; an auxiliary wiring formed on the substrate, which is insulated from the first electrode; an organic layer which includes a light emitting layer, covers at least the first electrode and the auxiliary wiring on the substrate, and has a break part on a side face of the auxiliary wiring; and a second electrode which covers the organic layer and is electrically connected to the auxiliary wiring at the break part of the organic layer.

In the organic light emitting device according to the invention and the display unit according to the invention, the organic layer has the break part on the side face of the auxiliary wiring. The auxiliary wiring and the second electrode are electrically connected through this break part. Therefore, a sheet resistance of the second electrode is lowered, and voltage drop in the second electrode is inhibited. Consequently, variation of luminance between a peripheral part and a central part of the display screen can be inhibited.

In the method of manufacturing an organic light emitting device according to the invention, the first electrode and the auxiliary wiring insulated from the first electrode are formed on the substrate. Subsequently, the organic layer including the light emitting layer is formed on at least the first electrode and the auxiliary wiring, and the break part is formed by breaking the organic layer by the step of the side face of the auxiliary wiring. After that, the second electrode is formed on the organic layer, and the second electrode and the auxiliary wiring are electrically connected at the break part of the organic layer.

According to the organic light emitting device of the invention and the display unit of the invention, the organic layer has the break part at the side face of the auxiliary wiring, and the auxiliary wiring and the second electrode are electrically connected through this break part. Therefore, voltage drop in the second electrode is inhibited by the auxiliary wiring, and variation of luminance in the screen can be inhibited. Consequently, a display quality can be improved.

According to the method of manufacturing an organic light emitting device of the invention, after the break part is formed by breaking the organic layer by the step of the side face of the auxiliary wiring, the second electrode and the auxiliary wiring are electrically connected through this break part. Therefore, even when the organic layer is formed without using a mask for pixel coating, the auxiliary wiring and the second electrode can be electrically connected. Consequently, deposition failure such as lack of the organic layer due to displacement or influence of thermal expansion of the mask for pixel coating can be prevented to improve process yield, which is significantly advantageous for making a high-definition display. Further, it is possible to prevent dust and the like adhering to the mask for pixel coating from adhering to the organic layer and the like, which leads to a cause of short circuit. Furthermore, no extra process is needed to electrically connect the second electrode and the auxiliary wiring. Therefore, the number of processes can be less.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the invention will be hereinafter described in detail with reference to the drawings.

FIG. 3shows a cross sectional structure of a display unit according to a first embodiment of the invention. This display unit is used as an ultrathin organic light emitting display, wherein a driving panel10and a sealing panel20are placed opposite, and their whole surfaces are bonded together by an adhesive layer30made of, for example, a thermosetting resin. The driving panel10is, for example, sequentially provided with an organic light emitting device10R generating red light, an organic light emitting device10G generating green light, and an organic light emitting device10B generating blue light in the shape of a matrix as a whole on a substrate11made of an insulating material such as glass with a TFT12and a planarizing layer13in between.

The TFT12is an active device corresponding to the respective organic light emitting devices10R,10G, and10B. The organic light emitting devices10R,10G, and10B are driven by active matrix method. A gate electrode of the TFT12(not shown) is connected to an unshown scanning circuit. A source and a drain (not shown either) are connected to a wiring12B provided through an interlayer insulating film12A made of silicon oxide, PSG (Phospho-Silicate Glass) or the like. The wiring12B is connected to the source and the drain of the TFT12through an unshown connecting hole provided at the interlayer insulating film12A, and is used as a signal line. The wiring12B is made of, for example, aluminum (Al) or an aluminum (Al)-copper (Cu) alloy. A construction of the TFT12is not particularly limited, and can be, for example, bottom gate type or top gate type.

The planarizing layer13is intended to planarize a surface of the substrate11on which the TFT12is formed, and form each layer having a uniform film thickness of the organic light emitting devices10R,10G, and10B. The planarizing layer13is provided with a connecting hole13A to connect a first electrode14of the organic light emitting devices10R,10G, and10B and the wiring12B. The planarizing layer13is preferably made of a material having a good pattern precision since the fine connecting hole13A is formed in the planarizing layer13. As a material for the planarizing layer13, an organic material such as polyimide or an inorganic material such as silicon oxide (SiO2) can be used.

In the organic light emitting devices10R,10G, and10B, for example, the first electrode14as an anode, an insulating film15, an organic layer16including a light emitting layer, and a second electrode17as a cathode are layered in this order from the substrate11side with the TFT12and the planarizing layer13in between. An auxiliary wiring18which is electrically insulated from the first electrode14is formed on the substrate11. A side face of this auxiliary wiring18and the second electrode17are electrically connected. A protective film19is formed on the second electrode17as necessary.

The first electrode14also has a function as a reflective layer. It is desirable that the first electrode14has reflectance as high as possible in order to improve light emitting efficiency. For example, as a material to make the first electrode14, a simple substance or an alloy of metal elements such as platinum (Pt), gold (Au), silver (Ag), chromium (Cr), and tungsten (W) can be cited. It is preferable that a thickness of the first electrode14in the lamination direction (hereinafter simply referred to as thickness) is set to 100 nm to 300 nm. The first electrode14can have a monolayer structure or a laminated structure of a plurality of layers.

The insulating film15is intended to secure insulation between the first electrode14and the second electrode17, and to accurately make a desired form of light emitting regions in the organic light emitting devices10R,10G, and10B. The insulating film15has, for example, a film thickness of about 600 nm, and is made of an insulating material such as silicon oxide and polyimide. The insulating film15is provided with an aperture15A corresponding to the light emitting regions in the organic light emitting devices10R,10G, and10B, and an aperture15B corresponding to the auxiliary wiring18.

The organic layer16is formed on the first electrode14, the insulating film15, and the auxiliary wiring18. The organic layer16has a break part16A broken at the side face of the auxiliary wiring18. The auxiliary wiring18and the second electrode17are electrically connected through this break part16A. A construction and a material of the organic layer16will be described later.

The second electrode17has a structure wherein a semi-transparent electrode17A having semi-transparency to light generated in a light emitting layer, and a transparent electrode17B having semi-transparency to light generated in the light emitting layer are layered in this order from the organic layer16side. The semi-transparent electrode17A has, for example, a thickness of about 10 nm, and is made of metal or an alloy of silver (Ag), aluminum (Al), magnesium (Mg), calcium (Ca), sodium (Na) and the like. In this embodiment, the semi-transparent electrode17A is, for example, made of an alloy of magnesium (Mg) and silver (MgAg alloy).

The transparent electrode17B is intended to lower an electric resistance of the semi-transparent electrode17A, and reduce a contact resistance between the second electrode17and the auxiliary wiring18by increasing a contact area between the second electrode17and the auxiliary wiring18. The transparent electrode17B is made of a conductive material having semi-transparency sufficient for the light generated in the light emitting layer. Regarding a material making the transparent electrode17B, for example, the transparent electrode17B is preferably made of at least one of indium oxides (InOx), tin oxides (SnOx), and zinc oxides (ZnOx). Specifically, for example, the transparent electrode17B is preferably made of a compound (IZO) containing indium, zinc (Zn), and oxygen, since good conductivity and high transmittance can be obtained even when deposition is made under room temperatures. A thickness of the transparent electrode17B is preferably, for example, about 200 nm.

The auxiliary wiring18is intended to inhibit voltage drop in the second electrode17. The auxiliary wiring18is formed, for example, at the aperture15B of the insulating film15, and is made of the same material as of the first electrode14. Since the auxiliary wiring18is made of the same material as of the first electrode14, the auxiliary wiring18and the first electrode14can be formed in the same process in a manufacturing process described later. It is not always necessary that a material and a construction of the auxiliary wiring18are the same as of the first electrode14.

A thickness of the auxiliary wiring18is preferably larger than a thickness of the organic layer16. The reason thereof is that the break part16A can be formed by breaking the organic layer16by a step of the side face of the auxiliary wiring18when the organic layer16is deposited in the manufacturing process described later. In the case that the auxiliary wiring18or the organic layer16has a laminated structure of a plurality of layers, the thickness of the auxiliary wiring18or the thickness of the organic layer16means a total thickness of the plurality of layers.

The side face of the auxiliary wiring18is preferably perpendicular, or reversely tapered to the substrate11. The reason thereof is that such a shape prevents the side face of the auxiliary wiring18from being covered with the organic layer16, and makes it easy for the break part16A to be formed in the after-mentioned manufacturing process. A taper angle θ of the side face of the auxiliary wiring18to a flat face11A of the substrate11is preferably, for example, about from 90° to 120°. If the taper angle θ is too large, it may be hard to contact the second electrode17to the side face of the auxiliary wiring18.

The protective film19has, for example, a thickness of 500 nm to 10,000 nm, and is a passivation film made of a transparent dielectric. The protective film19is, for example, made of silicon oxide (SiO2), silicon nitride (SiN) and the like.

The sealing panel20is located on the second electrode17side of the driving panel10, and has a sealing substrate21to seal the organic light emitting devices10R,10G, and10B together with the adhesive layer30. The sealing substrate21is made of a material such as glass which is transparent to the light generated in the organic light emitting devices10R,10G, and10B. The sealing substrate21is provided with, for example, the color filter22, which extracts the light generated in the organic light emitting devices10R,10G, and10B, absorbs outside light reflected in the organic light emitting devices10R,10G, and10B and the wiring therebetween, and improves contrast.

The color filter22can be provided on either side of the sealing substrate21. However, it is preferable to provide the color filter22on the driving panel10side, since the color filter22is not exposed on the surface, and can be protected by the adhesive layer30. The color filter22has a red filter22R, a green filter22G, and a blue filter22B, which are orderly arranged correspondingly to the organic light emitting devices10R,10G, and10B.

The red filter22R, the green filter22G, and the blue filter22B are respectively, for example, formed in the shape of a rectangle with no clearance in between. The red filter22R, the green filter22G, and the blue filter22B are respectively made of a resin mixed with a pigment and are adjusted so that light transmittance in the targeted red, green, or blue wavelength band becomes high and light transmittance in other wavelength bands becomes low by selecting a pigment.

FIGS. 4A to 4Crespectively show enlarged constructions of the organic light emitting devices10R,10G, and10B. The first electrode14has preferably, for example, a laminated structure wherein a contact layer14A, a reflective layer14B, and a barrier layer14C are layered in this order from the substrate11side. The contact layer14A is intended to prevent the reflective layer14B from separating from the planarizing layer13. The reflective layer14B is intended to reflect the light generated in the light emitting layer. The barrier layer14C prevents silver or an alloy containing silver making the reflective layer14B from reacting with oxygen in the air or sulfur component, and has a function as a protective film to reduce damage to the reflective layer14B even in a manufacturing process after forming the reflective layer14B.

The contact layer14A has, for example, a thickness of 5 nm to 50 nm. In this embodiment, for example, the contact layer14A has a thickness of 20 nm, and is made of a compound (ITO: Indium Tin Oxide) containing indium (In), tin (Sn), and oxygen (O). The reflective layer14B has, for example, a thickness of 50 nm to 200 nm. In this embodiment, the reflective layer14B has, for example, a thickness of 200 nm, and is made of silver (Ag) or an alloy containing silver in order to reduce light absorptance loss and improve reflectivity. The barrier layer14C has, for example, a thickness of 1 nm to 50 nm, and is made of ITO. In this embodiment, a thickness of the barrier layer14C varies according to light emitting colors of the organic light emitting devices10R,10G, and10B, since an after-mentioned resonator structure is introduced to the organic light emitting devices10R,10G, and10B.

The organic layer16has the same structure regardless of light emitting colors of the organic light emitting devices10R,10G, and10B. For example, in the organic layer16, an electron hole transport layer41, a light emitting layer42, and an electron transport layer43are layered in this order from the first electrode14side. The electron hole transport layer41is intended to improve efficiency to inject electron holes into the light emitting layer42. In this embodiment, the electron hole transport layer41also has a function as an electron hole injection layer. The light emitting layer42is intended to generate light by recombination of electrons and electron holes caused by application of electric field. Light is emitted in a region corresponding to the aperture15A of the insulating film15. The electron transport layer43is intended to improve efficiency to inject electrons into the light emitting layer42.

The electron hole transport layer41has, for example, a thickness of about 40 nm, and is made of 4,4′,4″-tris (3-methylphenyl phenylamino)triphenylamine (m-MTDATA) or α-naphthyl phenyldiamine (αNPD).

The light emitting layer42is a light emitting layer for white light emitting. The light emitting layer42has, for example, a red light emitting layer42R, a green light emitting layer42G, and a blue light emitting layer42B, which are layered on each other between the first electrode14and the second electrode17. The red light emitting layer42R, the green light emitting layer42G, and the blue light emitting layer42B are layered in this order from the anode, the first electrode14side. The red light emitting layer42R generates red light by recombination of part of electron holes injected from the first electrode14through the electron hole transport layer41and part of electrons injected from the second electrode17through the electron transport layer43, which is caused by application of electric field. The green light emitting layer42G generates green light by recombination of part of electron holes injected from the first electrode14through the electron hole transport layer41and part of electrons injected from the second electrode17through the electron transport layer43, which is caused by application of electric field. The blue light emitting layer42B generates blue light by recombination of part of electron holes injected from the first electrode14through the electron hole transport layer41and part of electrons injected from the second electrode17through the electron transport layer43, which is caused by application of electric field.

The red light emitting layer42R contains, for example, at least one of a red light emitting material, an electron hole transport material, an electron transport material, and a both charge transport material. The red light emitting material can be fluorescent or phosphorescent. In this embodiment, the red light emitting layer42R has, for example, a thickness of about 5 nm, and is made of a material wherein 30% by weight of 2,6-bis[(4′-methoxy diphenylamino)styryl]-1,5-dicyano naphthalene (BSN) is mixed in 4,4′-bis(2,2′-diphenyl vinyl)biphenyl (DPVBi).

The green light emitting layer42G contains at least one of a green light emitting material, an electron hole transport material, an electron transport material, and a both charge transport material. The green light emitting material can be fluorescent or phosphorescent. In this embodiment, the green light emitting layer42G has, for example, a thickness of about 10 nm, and is made of a material wherein 5% by weight of coumarin 6 is mixed with DPVBi.

The blue light emitting layer42B contains at least one of a blue light emitting material, an electron hole transport material, an electron transport material, and a both charge transport material. The blue light emitting material can be fluorescent or phosphorescent. In this embodiment, the blue light emitting layer42B has, for example, a thickness of about 30 nm, and is made of a material wherein 2.5% by weight of 4,4′-bis[2-{4-(N,N-diphenylamino)phenyl}vinyl]biphenyl (DPAVBi) is mixed with DPVBi.

The electron transport layer43has, for example, a thickness of about 20 nm, and is made of 8-hydroxyquinoline aluminum (Alq3).

The semi-transparent electrode17A also has a function as a semi-transparent reflective layer which reflects the light generated in the light emitting layer42between the first electrode14and the reflective layer14B. That is, the organic light emitting devices10R,10G, and10B have a resonator structure wherein the light generated in the light emitting layer42is resonated and extracted from a second end P2side, by setting an interface between the reflective layer14B and the barrier layer14C of the first electrode14to a first end P1, setting an interface of the semi-transparent electrode17A on the light emitting layer42side to the second end P2, and setting the organic layer16and the barrier layer14C to a resonance part.

It is preferable that the organic light emitting devices10R,10G, and10B have such a resonator structure, since the light generated in the light emitting layer42generates multiple interference, and acts as a kind of narrow band filter, and therefore, a half value width of a spectrum of the light to be extracted is reduced and color purity can be improved. Further, as described above, it is preferable that a thickness of the barrier layer14C is adjusted corresponding to light emitting colors of the organic light emitting devices10R,10G, and10B to obtain different optical distances L between the first end P1and the second end P2, since only light desired to be extracted among red light generated in the red light emitting layer42R, green light generated in the green light emitting layer42G, and blue light generated in the blue light emitting layer42B can be resonated and extracted from the second end P2side.

Further, it is preferable that the organic light emitting devices10R,10G, and10B have such a resonator structure, since outside light entering from the sealing panel20can be attenuated by the multiple interference, and reflectance of outside light in the organic light emitting devices10R,10G, and10B can be significantly reduced by combination with the color filter22shown inFIG. 3. That is, by corresponding the wavelength range having high transmittance in the color filter22with peak wavelength λ of the spectrum of light to be extracted from the resonator structure, only light having a wavelength equal to the peak wavelength λ of the spectrum of light to be extracted among the outside light entering from the sealing panel20passes through the color filter22, and other outside light having other wavelengths is prevented from entering the organic light emitting devices10R,10G, and10B.

To that end, it is preferable that the optical distance L between the first end P1and the second end P2of the resonator satisfies mathematical formula 1, and a resonance wavelength of the resonator (peak wavelength of a spectrum of light to be extracted) corresponds with a peak wavelength of a spectrum of light desired to be extracted. Actually, it is preferable that the optical distance L is selected to be a positive minimum value which satisfies the mathematical formula 1.
(2L)/λ+Φ/(2π)=m(Mathematical Formula 1)
where L represents an optical distance between the first end P1and the second end P2, Φ represents a sum (Φ=Φ1+Φ2) (rad) of phase shiftΦ1of reflected light generated in the first end P1and phase shift Φ2of reflected light generated in the second end P2, λ represents a peak wavelength of a spectrum of light desired to be extracted from the second end P2side, and m represents an integral number to make L positive, respectively. In the mathematical formula 1, units for L and λ should be common, for example, nm is used as a common unit.

This display unit can be manufactured, for example, as below.

FIGS. 5A and 5Bto12show a method of manufacturing the display unit in order of processes. First, as shown inFIG. 5A, the TFT12, the interlayer insulating film12A, and the wiring12B are formed on the substrate11made of the foregoing material.

Next, as shown inFIG. 5B, the planarizing layer13made of the foregoing material is formed on a whole surface of the substrate11by, for example, spin coat method. The planarizing layer13is patterned in a given shape by exposure and development, and the connecting hole13A is formed.

Subsequently, as shown inFIG. 6A, the first electrode14made of the foregoing material and having the foregoing thickness is formed on the planarizing layer13. At this time, it is preferable that the auxiliary wiring18is formed in the same process as of the first electrode14.

The first electrode14and the auxiliary wiring18can be formed, for example, by firstly forming the contact layer14A, the reflective layer14B, and the barrier layer14C (refer toFIGS. 4A,4B, and4C) sequentially, and then etching the barrier layer14C, the reflective layer14B, and the contact layer14A by using, for example, lithography technique. The contact layer14A and the barrier layer14C are formed by, for example, DC sputtering method, wherein mixed gas of argon (Ar) and oxygen (O2) is used as sputtering gas, the pressure is, for example, 0.4 Pa, and the output is, for example, 300 W. The reflective layer14B is formed by, for example, DC sputtering method, wherein argon (Ar) gas is used as sputtering gas, the pressure is, for example, 0.5 Pa, and the output is, for example, 300 W. When etching is performed, a thickness of the barrier layer14C is varied according to light emitting colors of the organic light emitting devices10R,10G, and10B.

After that, as shown inFIG. 6B, the insulating film15with the foregoing thickness is deposited on a whole surface of the substrate11by, for example, CVD (Chemical Vapor Deposition) method. The apertures15A and15B are formed by selectively removing part of the insulating film15corresponding to the light emitting region and part of the insulating film15corresponding to the auxiliary wiring18by using, for example, lithography technique. Then, the aperture15B is formed so that a side face of the auxiliary wiring18is exposed.

Next, as shown inFIG. 7, the organic layer16is formed by sequentially depositing the electron hole transport layer41, the light emitting layer42, and the electron transport layer43(refer toFIGS. 4Ato4C) made of the foregoing material and having the foregoing thickness on the first electrode14, the insulating film15, and the auxiliary wiring18by, for example, deposition method. Then, as shown inFIG. 8, the organic layer16is deposited on the whole surface of the substrate11except for a periphery of the substrate11and a part where an unshown extraction electrode is formed by using a metallic area mask51having an aperture51A corresponding to an area to form the organic layer16. In the result, though a top face of the auxiliary wiring18is covered with the organic layer16, the organic layer16is broken by a step at the side face of the auxiliary wiring18, and therefore, the break part16A is formed.

Subsequently, as shown inFIG. 9, the second electrode17is formed by sequentially forming the semi-transparent electrode17A and the transparent electrode17B made of the foregoing material and having the foregoing thickness on the organic layer16. In the result, the second electrode17is electrically connected to the auxiliary wiring18at the break part16A of the organic layer16.

Specifically, first, the semi-transparent electrode17A is formed by, for example, deposition method. That is, for example, regarding magnesium and silver making the semi-transparent electrode17A, for example, 0.1 g of magnesium and 0.4 g of silver are filled in different boats for resistance heating respectively, and the boats are attached to a given electrode of an unshown vacuum deposition apparatus. Next, after atmosphere in the vacuum deposition apparatus is, for example, depressurized down to 1.0×10−4Pa, voltage is applied to the respective boats for resistance heating, the boats are heated, and magnesium and silver are deposited together. A ratio between growth rates of magnesium and silver is, for example, 9:1.

After that, the transparent electrode17B is deposited on the semi-transparent electrode17A. In the result, a contact area between the auxiliary wiring18and the second electrode17can be increased, and a contact resistance therebetween can be decreased. The transparent electrode17B is preferably formed by sputtering method such as DC sputtering method. Since coating characteristics are high in the sputtering method compared to in vacuum deposition method, the transparent electrode17B can be well formed on the side face of the auxiliary wiring18. As sputtering gas, for example, mixed gas of argon and oxygen (volume ratio: Ar:O2=1,000:5) is used. The pressure is, for example, 0.3 Pa, and the output is, for example, 400 W.

Next, as shown inFIG. 10, the protective film19made of the foregoing material and having the foregoing thickness is formed on the second electrode17. The driving panel10shown inFIG. 3is thereby formed.

Further, as shown inFIG. 11A, the red filter22R is formed by, for example, coating a material for the red filter22R on the sealing substrate21made of the foregoing material by spin coating or the like, and patterning by photolithography technique and firing. Subsequently, as shown in FIG.11B, as in the red filter22R, the blue filter22B and the green filter22G are sequentially formed. The sealing panel20is thereby formed.

After forming the sealing panel20and the driving panel10, as shown inFIG. 12, the adhesive layer30made of a thermosetting resin is coated on the side where the organic light emitting devices10R,10G, and10B are formed of the substrate11. Coating can be performed, for example, by discharging the resin from a slit nozzle dispenser, by roll coating or by screen printing. Next, as shown inFIG. 3, the driving panel10and -the sealing panel20are bonded together with the adhesive layer30in between. Then, it is preferable that a side of the sealing panel20on which the color filter22is formed faces to the driving panel10. Further, it is preferable to prevent air bubbles from mixing into the adhesive layer30. After that, a relative positions of the color filter22of the sealing panel20and the organic light emitting devices10R,10G, and10B of the driving panel10are aligned. Next, heat treatment is performed for given time at a given temperature, and the thermosetting resin of the adhesive layer30is cured. As above, the display unit shown inFIGS. 3 to 4Cis completed.

In this display unit, for example, when a given voltage is applied between the first electrode14and the second electrode17, a current is applied to the red light emitting layer42R, the green light emitting layer42G, and the blue light emitting layer42B of the organic layer16. Then, electron holes and electrons recombine with each other, and therefore, red light, green light, blue light are respectively generated in the red light emitting layer42R, the green light emitting layer42G, and the blue light emitting layer42B. Regarding the red, green, and blue light, according to the optical distance L between the first end P1and the second end P2of the organic light emitting devices10R,10G, and10B, only red light hRin the organic light emitting device10R, only green light hGin the organic light emitting device10G, and only blue light hBin the organic light emitting device10B are multiple-reflected between the first end P1and the second end P2, and then extracted through the second electrode17. Here, the organic layer16has the break part16A on the side face of the auxiliary wiring18, and the auxiliary wiring18and the second electrode17are electrically connected through this break part16A. Therefore, voltage drop in the second electrode17can be inhibited. Consequently, variation of luminance between a peripheral part and a central part of the display screen can be inhibited.

As above, in this embodiment, the organic layer16has the break part16A on the side face of the auxiliary wiring18, and the auxiliary wiring18and the second electrode17are electrically connected through this break part16A. Therefore, voltage drop in the second electrode17can be inhibited by the auxiliary wiring18, and variation of luminance in the screen can be inhibited. Consequently, its display quality can be improved.

Further, in this embodiment, first, the break part16A is formed by breaking the organic layer16by the step of the side face of the auxiliary wiring18, and then the second electrode17and the auxiliary wiring18are electrically connected through this break part16A. Therefore, even when the organic layer16is formed without using the mask for pixel coating, the auxiliary wiring18and the second electrode17can be electrically connected. In the result, deposition failure such as lack of the organic layer16due to displacement or influence of thermal expansion of the mask for pixel coating can be prevented to improve process yield, which is significantly advantageous for making a high-definition display. Further, it is possible to prevent dust and the like adhering to the mask for pixel coating from adhering to the organic layer16and the like, which leads to a cause of short circuit. Furthermore, no extra process is needed to electrically connect the second electrode17and the auxiliary wiring18. Therefore, the number of processes can be less.

FIG. 13shows a cross sectional structure of a display unit according to a second embodiment. This display unit is the same as the display unit of the foregoing first embodiment except that an auxiliary wiring68is provided on the insulating film15. Therefore, the same symbols are applied to the same components as of the first embodiment and explanation thereof will be omitted.

The auxiliary wiring68has a monolayer structure or a laminated structure of a low resistance conductive material such as aluminum (Al) and chromium (Cr). A width and a thickness of the auxiliary wiring68vary according to dimensions of a screen, materials and thicknesses of the second electrode and the like. In this embodiment, the auxiliary wiring68can have a different construction from that of the first electrode14, and the construction of the auxiliary wiring68is not bound by a material or a thickness of the first electrode14. Therefore, for example, it is possible to lower a sheet resistance of the second electrode17by making a thickness of the auxiliary wiring68larger than that of the first electrode14.

This display unit can be, for example, manufactured as below.

First, as shown inFIGS. 5A to 6Ain the first embodiment, the TFT12, the planarizing layer13, and the first electrode14are formed on the substrate11made of the foregoing material.

After that, as shown inFIG. 14A, the insulating film15with the foregoing thickness is deposited on a whole surface of the substrate11by, for example, CVD method. The aperture15A is formed by selectively removing a part of the insulating film15corresponding to the light emitting region by using, for example, lithography technique.

Subsequently, as shown inFIG. 14B, the auxiliary wiring68made of the foregoing material is formed on the insulating film15.

After that, as shown inFIG. 15A, the organic layer16is formed on the first electrode14, the insulating film15, and the auxiliary wiring68, and the break part16A is formed on a side face of the auxiliary wiring68as in the first embodiment.

Subsequently, as shown inFIG. 15B, the semi-transparent electrode17A and the transparent electrode17B made of the foregoing material and having the foregoing thickness are formed on the organic layer16as in the first embodiment. The second electrode17is thereby electrically connected to the auxiliary wiring68at the break part16A of the organic layer16.

After that, as in the first embodiment, the protective film19made of the foregoing material and having the foregoing thickness is formed on the second electrode17to form the driving panel10. This driving panel10and the sealing panel20are bonded together with the adhesive layer30in between. As above, the display unit shown inFIG. 13is completed.

This display unit operates as in the first embodiment, and provides effects similar to that of the first embodiment.

While the invention has been described with reference to the embodiments, the invention is not limited to the foregoing embodiments, and various changes may be made. For example, in the foregoing embodiments, the case wherein the break parts16A are formed on the both side faces of the auxiliary wiring18or68has been described. However, it is possible that the break part16A is formed at least on part of the side faces of the auxiliary wiring18or68. For example, it is possible to form the break part16A on only one side face of the auxiliary wiring18or68.

Further, for example, in the foregoing embodiments, the case wherein the auxiliary wiring18or68has a planar shape of a simple line segment has been described. However, the shape of the auxiliary wiring18or68is not particularly limited. For example, for the purpose of increasing a contact area with the second electrode17by increasing an area of the side face of the auxiliary wiring18or68, an auxiliary wiring provided with holes18A as shown inFIG. 16or an auxiliary wiring provided with notches18B on its side face as shown inFIG. 17Acan be thought. A shape, the number, a position and the like of the hole18A or the notch18B are not particularly limited. In addition, the hole18A and the notch18B can be used at the same time.

Further, for example, in the first embodiment, the case wherein the aperture15B of the insulating film15is formed so that the both side faces of the auxiliary wiring18are exposed has been described. However, it is possible that the aperture15B of the insulating film15is formed so that at least part of the side faces of the auxiliary wiring18is exposed. For example, it is possible to form the aperture15B so that only one side face of the auxiliary wiring18is exposed.

In addition, for example, materials, thicknesses, deposition methods, and deposition conditions of the respective layers, which have been described in the foregoing embodiments, are not limited to the above. Other materials, thicknesses, deposition methods, and deposition conditions can be applied. For example, materials for the contact layer14A and the barrier layer14C are not limited to the foregoing ITO and can be a metal compound or a conductive oxide containing at least one element from the group consisting of indium (In), tin (Sn), and zinc (Zn), more specifically, can be at least one from the group consisting of ITO, IZO, indium oxide (In2O3), tin oxide (SnO2), and zinc oxide (ZnO). Further, a material for the contact layer14A is not necessarily transparent.

Further, for example, in the foregoing embodiments, the constructions of the organic light emitting device and the display unit have been described with reference to the concrete examples. However, it is not necessary to provide all layers such as the protective film19, and it is possible to further provide other layer. For example, it is possible that in the second electrode17, the transparent electrode17B is omitted, and only the semi-transparent electrode17A is provided. Otherwise, it is possible that in the second electrode17, the semi-transparent electrode17A is omitted, and only the transparent electrode17B is provided. In the case that the second electrode17is composed of only the transparent electrode17B as above, it is possible that a thickness of the barrier layer14C is the same for the organic light emitting devices10R,10G, and10B, and the foregoing resonator structure is omitted.

In addition, in the foregoing embodiments, the case wherein in the first electrode14, the contact layer14A, the reflective layer14B, and the barrier layer14C are formed in this order from the substrate11side has been described. However, one or both of the contact layer14A and the barrier layer14C can be omitted.

Further, in the foregoing embodiments, the case wherein the light emitting layer for white light emitting is formed as the light emitting layer42of the organic layer16, and color display is performed by using the foregoing resonator structure and the color filter22has been described. However, it is possible to perform the color display by using only the color filter22without using the resonator structure. Further, it is possible to perform the color display by using an optical filter or the like to let through only light having specific wavelengths, instead of the color filter22.

Further, in the foregoing embodiments, the case wherein the light emitting layer for white light emitting containing three layers of the red light emitting layer42R, the green light emitting layer42G, and the blue light emitting layer42B is formed as the light emitting layer42of the organic layer16has been described. However, a construction of the light emitting layer42for white light emitting is not particularly limited, and can be a laminated structure of light emitting layers of two colors in relation of complimentary colors to each other, such as an orange light emitting layer and a blue light emitting layer, and a blue-green light emitting layer and a red light emitting layer.

Further, it is not always necessary that the light emitting layer42of the organic layer16is the light emitting layer for white light emitting. The invention can be applied to a color changing type full-color display unit, wherein the green light emitting and the red light emitting are obtained from the blue light emitting layer other than the blue light emitting through a color changing layer, and to a mono-color display unit, wherein, for example, only the green light emitting layer42G is formed.

Further, in the foregoing embodiments, the case wherein the organic light emitting devices10R,10G, and10B are sealed by bonding the driving panel10and the sealing panel20with the adhesive layer30in between has been described. However, a sealing method is not particularly limited. For example, sealing can be performed by arranging a sealing can on a rear face of the driving panel10.

Further, in the foregoing embodiments, the case wherein the first electrode14is an anode and the second electrode17is a cathode has been described. However, it is possible to reverse the anode and the cathode, that is, the first electrode14can be a cathode and the second electrode17can be an anode. In this case, as a material for the second electrode17, a simple substance or an alloy of gold, silver, platinum, copper or the like is suitable. However, other material can be used by providing a layer similar to the barrier layer14C in the foregoing embodiments on the surface of the second electrode17. Further, when the first electrode14is a cathode and the second electrode17is an anode, it is preferable that in the light emitting layer42, the red light emitting layer42R, the green light emitting layer42G, and the blue light emitting layer42B are layered in this order from the second electrode17side.

Further, in the foregoing embodiments, the case wherein the sealing substrate21is provided with the color filter22has been described. However, it is possible to provide a reflected light absorption film as a black matrix along interfaces between the red filter22R, the green filter22G, and the blue filter22B as necessary. The reflected light absorption film can be made of a black resin film mixed with black colorant having optical density of one or more, or a thin film filter utilizing interference of the thin films. The black resin film is preferably used, since the black resin film can be formed inexpensively and easily. The thin film filter has, for example, a laminated structure of one or more thin film layers made of metal, a metallic nitride, or a metallic oxide. The thin film filter attenuates light by utilizing interference of the thin films. Concrete examples of the thin film filter include a lamination wherein chromium and chromium oxide (III) (Cr2O3) are alternately layered.