Display device

Technical Field

The invention relates to having the organic electroluminescent element (organic EL element) as a light source field sequential mode display device.

Background Art

As the display device, the display device of the sequential mode. The application of the sequential mode is sustained switching issued 2 more than for the color of the light, will be its switching speed of more than human eye in time is set as the resolution of the speed, people color identification 2 more than the color of the color mode. Field sequential mode is based on the "time division (time - division)" of the color of the color display mode.

The field sequence mode in the display device, as a direct type or side of the backlight source of reason, made organic electroluminescent (EL) element to replace the LED (for example with reference to the Patent document 1, Patent document 2).

The field sequence mode in the display device, the video display, back light source can emit a red (R), green (G), blue (B) in any of the color, and according to the ongoing switching (time division) emit light, by making the switching speed fast enough, arbitrarily color light.

For example, the color of the light into the field to field R, G B field of the field and of the state of the partition, to all of the RGB are sequentially applied to the field-emitting the time difference, on the display panel for a color field. At this time, while the field of the display R, the back light source of the light-emitting red (R), while the field of the display B, the back light source of light emitting a blue (B), while the field of the display G, the back light source of the light-emitting is a green (G).

By this time division of the 3 color of the color of the field on one side of the one side of the light-emitting color switching is carried out continuously display, can display color video.

Field sequential mode of the display device with the use of a color filter compared with the manner, not absorbing the light loss caused by, and because does not use the high color filter, so can reduce the number of parts, to reduce cost has a great advantage.

The prior technical literature

Patent literature

Patent document 1: Japanese opens especially 2008 - 66366 Bulletin

Patent document 2: Japanese opens especially 2007 - 172945 Bulletin

Content of the invention

This invention technical problem to be solved

However, in Patent document 1 which are recorded in the field sequential liquid crystal display device, the use of the installed on the base to form a red light (R) of the organic EL element, green-emitting (G) of the organic EL element, and a blue light (B) of the organic EL element of the organic EL element of three for the backlight source. In this way, if in the in the backlight using the red, green, blue this 3 hue to distinguish each other organic EL element is formed, is on the base plate, each of the issued light is actually part of the 1/3, the aperture ratio will be reduced.

In addition, in Patent document 2 which are recorded in the field sequential liquid crystal display device, in the outgoing direction of the laminated on the base plate along the red light (R), green (G) and blue light (B) of the luminescent layer of the organic EL element of the stack structure used for the backlight source. However, in such a stack structure of the organic EL element, is apart from the photoemission by is disposed on the surface (such as the base plate) of the position of the most distant of the light generated by the light-emitting layer arranged between the light emitting layer to light of other luminescent layer and electrode caused by the impact of the absorption and reflection. Therefore, the surface is apart from the photoemission is disposed furthest from the position of the luminescent layer and disposed on the light projecting side of the compared with the light emitting layer, the light efficiency is derived. In this way, in the field sequential mode in the backlight of the display device, because the increase of the electric power consumption, so the field sequential mode will increase the power consumption of the display device.

In order to solve the above problem, in the present invention to provide a fluctuation of the display device.

For the technical proposal of the technical problem to be solved

The present invention provides a display device, comprising a back light source and field sequential mode of the display panel, wherein the back light source of the light-emitting part comprising organic electroluminescent element, the organic electroluminescent element laminated with a plurality of different colors is emitted by the light-emitting unit, can emit the white light or yellow light emitting unit is arranged on one side of the closest to the light exit surface.

The effect of this invention

According to the present invention, it is possible to provide fluctuation of the display device.

Description of drawings

Figure 1 is the diagrammatic chart of 1st embodiment of the display device;

Figure 2 is the compend chart of 2nd embodiment of the display device;

Figure 3 is the equivalent wiring diagram and the time diagram of the organic EL element.

The mark description

100. 100 A back light source, 101 the transparent base plate, 102 1st electrode, 103,103 A 1st light-emitting unit, 104 1st intermediate electrode, 105 2nd light-emitting unit, 106 2nd intermediate electrode, 107 3rd light-emitting unit, 108 3rd the intermediate electrode, 109 4th light-emitting unit, 110 2nd electrode, 200 display panel, 201 polarizer, 202 transparent substrate, 203 the thin-film transistor, 204 pixel electrode, 205 orientated film, 206 the liquid crystal layer, 207 insulating layer, 208 spacer, 209 seal, 210 data line

Mode of execution

The following, description used for implementing embodiments of the invention examples, but the invention is not limited to the following examples.

It should be explained that, according to the following the order of the note.

1. 1st embodiment of the display device

2. The display device of the 2nd embodiment

3. Time diagram

" 1. 1st embodiment of the display device "

Figure 1 said field sequential mode of the display device of the diagrammatic drawings. Figure 1 shown in sequential mode of the display device has a display panel 200, and comprising organic electroluminescent element (organic EL element) of the backlight 100.

[Display panel]

Display panel 200 is through TFT (Thin Film Transistor) mode for high-speed driving of the field sequential liquid crystal display panel. Display panel 200 is well known structure of TFT mode, display panel 200 on the outer surface side of a polarizing plate 201 of the two sheets of transparent base plate 202 (such as a glass substrate or a transparent film substrate) is clamped between the liquid crystal layer 206.

In the lower side of the transparent substrate 202 is formed on the pixel electrode 204 and the thin-film transistor (TFT) 203. In addition, the transparent substrate 202 on, via an insulating layer 207 is configured with the data matrix 210 and scanning line (omit the graphic). But also, in the data line 210 and the point of intersection of the scanning line is configured with TFT203 and a pixel electrode 204.

In addition, the insulating layer 207 is formed above the orientation film 205 can be clamping of the high-speed response of the liquid crystal layer 206. The liquid crystal layer 206 by a spacer 208, seal 209 and a pair of orientation film 205 form wherein the sealing have liquid crystal layer 206 of the space.

The above-mentioned display panel 200 in order to through the field sequential mode display full-color picture of the requirement may be high-speed response, it is preferred to use the well-known ferroelectric liquid crystal or anti-ferroelectric liquid crystal capable of high-speed response of the liquid crystal display panel. In addition, also can use the OCB (Optically Compensated Bend, Optically Compensated Birefringence) type liquid crystal panel or MEMS (Micro Electro Mechanical Systems) type liquid crystal panel. In addition, display panel 200 because the sequential mode is suitable for the display device, so it is not provided with the color filter structure.

[Back light source]

Then, used for Figure 1 shown in sequential mode of the backlight 100 description of the. Back light source 100 of the light-emitting part of the organic EL element is formed of laminated type.

Figure 1 shown in the display device, form the source 100 with the light emitting part of the organic EL element has in the thickness direction (the outgoing direction of the) laminated on the 4 layer into the light-emitting unit of the so-called 4 layer stack structure. In addition, the organic EL element in the back light source 100 of the arrangement of the whole surface of the light emitting region is formed continuously.

In addition, as shown in Figure 1, form the source 100 of the organic EL element on the transparent substrate 101 according to the sequentially laminated on the 1st electrode 102, 1st light-emitting unit 103, 1st intermediate electrode 104, 2nd light emitting unit 105, 2nd intermediate electrode 106, 3rd light emitting unit 107, 3rd intermediate electrode 108, 4th light-emitting unit 109, and 2nd electrode 110. Moreover, in the organic EL element, 1st electrode 102, 1st intermediate electrode 104, 2nd intermediate electrode 106, 3rd intermediate electrode 108 and 2nd electrode 110 for their respective clamping of the 1st light-emitting unit 103, 2nd light-emitting unit 105, 3rd light emitting unit 107 and 4th light emitting unit 109 for the purposes, play the role of a cathode, the other party to play the role of the anode. In addition, the organic EL element according to at least one from a transparent substrate 101 side is derived of the light produced by a bottom emission type.

In this embodiment, is arranged on the side of the 1st most close to the base board of the light-emitting unit 103 is provided with the white (W) color of the light emitting unit. In addition, 2nd light-emitting unit 105 is provided with the red (R) color of the light emitting unit. 3rd light emitting unit 107 is provided with the green (G) color of the light emitting unit. 4th light emitting unit 109 is with blue (B) color of the light emitting unit. In addition, in this embodiment, if the 1st light-emitting unit 103 is white, then the 2nd light emitting unit 105, 3rd light emitting unit 107 and 4th light emitting unit 109 with a color can be red, green and blue of any kind, with those of the light color of the light emitting unit is set to be a laminated order of arbitrary order. In addition, white (W) in the color temperature of 2000K - 12000K range.

Each of the electrodes used to control each of the light emitting unit of the light-emitting driving control part is connected with the. By a drive control part is applied to the clamping each of the light emitting unit on the electrode of the driving voltage, the organic EL element so as to perform the drive control of the light emitting unit. By the drive control section performs driving control of the light emitting unit, thereby to R, G, B and W each light emitting color of the light-emitting unit 1st 103, 2nd light emitting unit 105, 3rd light emitting unit 107 and 4th light emitting unit 109 can be independent driving. In addition, through the driving control, each of the light-emitting unit of the light emitting time, the light-emitting brightness control.

The field sequence mode of the display device in the backlight, in order to time division driving mode to the organic EL light-emitting element and light-emitting color switching. In the display device, in order not to produce the color switching causes Image flicker (Flicker), needs to be about 1/60 seconds following cut field. In addition, in the above-mentioned structure of the organic EL element, is composed of four light-emitting unit is R, G, B and W this 4 color light emitting. Therefore, in order to time division driving the above-mentioned structure of the organic EL element and to every 1 to field 1 for color display, need to 1 frame carried out to at least 4 equal division. Namely, need at least to about 1/240 seconds following (about 4 milliseconds following) to the organic EL element to the time driving.

In the prior art in general may issue a R, G, B this 3 color 3 layer stack structure of the organic EL element is used for field sequential mode under the condition of the display device, the color field time division for the 1/3, issued sequentially R, G, B. For example, in the display panel side of the color of the light field in order to into the R of the field, the field B G field and of the state of the partition. And, on the backlight source, so that the R, G, B field are sequentially applied to the time difference of the light-emitting. At this time, while the field of the display R, the back light source of the light-emitting red (R), while the field of the display B, the back light source of light emitting a blue (B), while the field of the display G, the back light source of the light-emitting is a green (G).

Such time division of the 3 in the color of the color of the field side switching light-emitting color while continuously display, thereby to display a color field. For example, in the display device to make the color field display white (W) under the condition of, through the time division light-emitting of the R, G, B sequentially continuously light-emitting, continuous display of the field R, G of field and B field synthesis of white-light.

However, in the laminated light emitting unit into the organic EL element of the stack structure in, in each layer of the stack, to generate light reflection or absorption. Therefore, for example, in photoemission from one side of the formed surface of the light-emitting unit of the light emitting from the stack and the opposite side of the light exit surface of the light-emitting unit of the light-emitting light of respective different derived efficiency. Usually, the light beam from the laminated surface of the opposite side of the light-emitting unit of the light-emitting light guide with efficiency becomes low. Namely, in photoemission surface formed on one side of the light-emitting unit of the light emitting efficiency is high, in photoemission surface forming the opposite side of the light-emitting unit of the light-emitting efficiency is low.

In addition, in the above-mentioned stack structure of the organic EL element, in the case of to improve the luminance, the need to improve the light-emitting unit to the applied voltage, the improvement of the luminance of the luminescent layer. Therefore, the increase in power consumption. In particular, low efficiency of the laminated light derived with the light of a side opposite to the light-emitting unit in order to match the form of the light projecting face side of the light-emitting unit to improve the brightness, exerting a higher drive voltage. Therefore, in the light-emitting unit, light-emitting efficiency caused in reducing the increase of the power consumption becoming prominent.

By contrast, the embodiment of the configuration of the organic EL element closest to a side of the light of the light-emitting unit having a plurality of 1st W with a color of the light-emitting unit. Because of possessing has W with a color of the light-emitting unit, so as to and from the 3 layer of the light emitting unit R, G, B this 3 colors of photosynthesis to obtain the white light as compared with a case, is not susceptible to the laminated structure of the absorption caused by the impact of the lower the luminance. Therefore, in the most close to the light guide shorter W configuration has the color of the light emitting unit, so that the white light emitted by the other light-emitting unit not hinder, higher brightness can be obtained. Therefore, the organic EL element of the light-emitting efficiency is improved.

In particular, in the with W of the light-emitting unit and the color of R, G, B of compared with each light-emitting unit, under the condition of high light-emitting efficiency, the effect becomes significant. For example, want to through possessing high luminous efficiency of the white light emitting layer to improve the brightness of the organic EL element of the case, as long as the improve the brightness of the white light emitting layer can be, without the need to improve the light emitting efficiency is low and the layer of the brightness of the RGB. Therefore, by means of the white light emitting layer, the back light source of the light-emitting efficiency is improved, can realize the fluctuation.

In addition, in the organic EL element, as long as the emitting white light-emitting unit is disposed on a side closest to the light exit surface can be, for R, G, B of each of the light emitting unit of the configuration for the purposes, can be designed into a random structure.

In addition, emitting white light-emitting unit of the light emitting unit is not limited to R, G, B of 3 primary colors of each of the light emitting unit, can also be a combination of other color. For example, can be adopted can be issued with yellow, cyan, magenta and any one of the complementary color of the light emitting unit structure, or will issue a 3 primary color in any one of the light-emitting unit and the color of the light issued by any one of the light-emitting units of the structure.

The light-emitting unit to emit white light can be made for example by the light-emitting layer and a B issued yellow (YL) of the laminated structure of the luminescent layer, or in the light-emitting layer of the light-emitting dopant added B and YL structure of light-emitting dopant. In this way, the light-emitting unit to emit white light can not only has a single-layer structure of the luminescent layer, can also be provided with a plurality of light-emitting layer structure. This for the other R, G, B light emitting unit is also the same.

In addition, in the light emitting unit having a plurality of structure of the luminescent layer, the luminescent layer can be laminated directly each other, also can be used in the luminescent layer is arranged between the middle of the non-luminescence layer. The middle layer is commonly referred to as the intermediate electrode, the intermediate conducting layer, a charge generation layer, the electron extracting layer, tie layer, a middle insulating layer, as long as it has the side portions and the adjacent layer supplying the electronic, to the cathode side the adjacent layer of the supply hole of the function of the layer can be, can use the well-known material and structure. For example, can be used with the latter intermediate electrodes of the same structure.

[Organic EL element]

Then, to form the back light source with the light emitting part of the organic EL element of a description of the structure. In the organic EL element, 1st electrode 102, 1st intermediate electrode 104, 2nd intermediate electrode 106 and 3rd intermediate electrode 108 is used as the light transmittance of the electrode. In addition, the organic EL element in the light-emitting area is only by the 1st electrode 102, 1st intermediate electrode 104, 2nd intermediate electrode 106, 3rd intermediate electrode 108 and 2nd electrode 110 the portion 1st of the light-emitting unit 103, 2nd light-emitting unit 105 and 3rd light emitting unit 107. The following, the details of these various structure description of the.

[Substrate]

As the organic EL element of the transparent substrate 101, for example can be cited glass, plastic and the like, but is not limited to these. As the preferred use of the transparent substrate 101, can be cited glass, quartz, transparent resin film.

As the resin film, for example can be cited: polyethylene terephthalate (PET), polyethylene naphthalate (PEN) polyester, polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose three acetates (TAC), cellulose acetate butyrates, cellulose cellulosic acetate propionate (CAP), cellulose acetate phthalate, cellulose nitrate and cellulose esters or their derivatives, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, between the stereoregular polystyrene, polycarbonate, norbornene resin, poly methyl pentene, polyether ketone, polyimide, polyether sulfone (PES), polyphenylene sulfide, gathers the sulphone class, polyether imide, polyether imide, polyamide, fluorine resin, nylon, polymethyl methacrylate, acrylic or polyarylate type, Alton (tradenames JSR Company) or APEL (commodity name Mitsui chemical Company) such cyclic hydrocarbon resin and the like.

[1st electrode]

1st electrode 102 is an organic EL element of the transparent electrode, the use of the silver or silver as a main component is formed of an alloy of the conductive layer. In this, form the main component is the 1st electrode 102 is formed in the components of the highest rate of component.

As forming the 1st electrode 102 of silver (Ag) as the main component of the alloy, for example can be cited silver magnesium (AgMg), silver-copper (AgCu), silver-palladium (AgPd), silver palladium-copper (AgPdCu), silver indium (AgIn) and the like.

1st electrode 102 can also be silver or silver as a main component according to the needs of the alloy layer divided into a plurality of layer and laminated structure formed by.

In addition, the 1st electrode 102 is preferably in a layer thickness of 2 - 15 nm range, more preferably in the 3 - 12 nm range, particularly preferably in the 4 - 9 nm. In the thickness ratio of the 15 nm thin case, layer of absorbing elements or reflection components less, 1st electrode 102 of large light transmission rate. In addition, the thickness ratio of 2 nm thick circumstances, can fully guarantees the level of conductivity.

As the 1st electrode 102 of the film forming method, examples of the coating method, ink jet method, coating method, dipping process using the wet process method, evaporation (resistance heating, such as EB method), a sputtering method, CVD method such as a dry process such as the use of the method. Wherein the preferred application of a vapor deposition method.

(Base layer)

In addition, the use of silver or silver as a main component is formed of an alloy of the 1st of the electrode 102 is preferably formed on the following substrate layer. The base layer is set in the 1st electrode 102 of the transparent substrate 101 side of the layer.

The form of the base layer of the material, is not particularly limited, for example can be cited: containing comprising silver or silver as the main component of the alloy of the 1st electrode 102 is suppressed when forming a silver aggregation nitrogen atom or sulfur atom of the compound and the like, containing to the silver forming a growth nucleus of become Pd, Al, Ti, Pt, Mo and the like and the metal of the layer comprising zinc oxide layer.

In the substrate layer of low refractive index material (refractive index lower than the 1.7) the case that, as the upper limit of the thickness of a layer, needs to be less than 50 nm, especially preferably less than 30 nm, further preferably less than 10 nm, especially preferably less than 5 nm. The layer thickness is set by less than 50 nm, the optical loss can be suppressed to a minimum limit. On the other hand, as the lower limit of the layer thickness, the need for 0.05 nm or more, preferably 0.1 nm or more, especially preferably 0.3 nm or more. Through the layer thickness is set to be 0.05 nm or more, can make the base layer of the film is uniformly formed, can be uniformly to achieve its effect (inhibit the agglomeration of the silver).

In the substrate layer is made of a high refractive index material (refractive index 1.7 above) the case that, as the upper limit of the layer thickness, without any particular restrictions, as the lower limit of the layer thickness, and by the above-mentioned low refractive index material is formed as the same.

However, if the frame of the function of the substrate layer, as long as they can get homogeneous film forming the required layer thickness can be formed.

In the base layer for growth of the silver containing a nuclear metal in the case of layer, its thickness is preferably set to not hinder the organic EL element of the thickness of the light transmission of the degree, for example 5 nm the following. On the other hand, the substrate layer needs to be able to ensure that the 1st electrode 102 the film uniformity of the degree of thickness. As the thickness, the substrate layer as long as it is formed of various metal atoms to 1 atomic layer above layer can be obtained. In addition, the base layer is preferably a continuous film. In addition, in the substrate layer, even if the growth of the silver containing a nuclear metal layer defects exist in the continuous phase, as long as the defect than a 1st electrode 102 of the Ag atoms is small, can ensure that the 1st electrode 102 the film uniformity.

As the base layer of a compound containing a nitrogen atom, as long as it is in the molecule of the compound containing a nitrogen atom, it is not particularly limited, but preferably has a nitrogen atom as a hetero-atom in the heterocyclic compound. As to a nitrogen atom as a hetero-atom in the heterocyclic ring, can be cited: ethylenimine, aziridine, azetidine, nitrogen heterocyclic butadiene (azete), pyrrolidine, azole, aza-cyclohexane (azinane), pyridine, because six hydrogen aa age, because aa age, imidazole, pyrazole, oxazole, thiazole, imidazoline, pyrazine, morpholine, thiazine, indole, isoindole, benzimidazole, purine, quinoline, isoquinoline, quinoxaline, cinnoline, small dish ding, acridine, carbazole, benzo - C - cinnoline, porphyrin, chlorin, choline and the like.

As the base layer of the film-forming method, can be cited the coating method, ink jet method, coating method, dipping process using the wet process method, vacuum evaporation (resistance heating, such as EB method), sputtering method, ion plating spreads the law law, plasma CVD method, the thermal CVD method such as a dry process such as the use of the method. Wherein from the point of view of film forming, preferably by electron beam vapor deposition method or a sputtering method is formed. In the case of electron beam vapor deposition method, in order to improve the film density, preferably use the IAD (ion assisted deposition) and other auxiliary vapor deposition.

In addition, the base layer of a layer comprising zinc oxide (zinc oxide-containing layer) containing zinc oxide (ZnO) as the main component. Zinc oxide layer of the composition of the main component is formed in the highest rate of component, is preferably 50 atomic % or more. Through the use of zinc oxide layer as the 1st electrode 102 of the substrate layer, can make the 1st electrode 102 containing silver atoms in the arrangement of the uniform, can be with the light transmissive and resistance characteristic.

Zinc oxide layer can also contain zinc oxide of a material other than. As the zinc oxide contained in the layer of a material other than zinc oxide, can be a dielectric material, or the oxide semiconductor material, an insulating material, can also be a conductive material. As the zinc oxide contained in the layer, dielectric material or oxide semiconductor material, for example containing TiO₂ , ITO (indium tin oxide), ZnS, Nb₂ O₅ , ZrO₂ , CeO₂ , Ta₂ O₅ , Ti₃ O₅ , Ti₄ O₇ , Ti₂ O₃ , TiO, SnO₂ , La₂ Ti₂ O₇ , IZO (indium zinc oxide -), AZO (Al of doped ZnO), GZO (Ga of the doped ZnO), ATO (Sb of doped SnO), ICO (indium cerium oxide), Ga₂ O₃ And the like. In the zinc oxide layer may only contain a dielectric material or the oxide semiconductor material, also can contain 2 or more. Dielectric material or oxide semiconductor material especially preferably ZnS, TiO₂ , GZO, ITO.

In addition, in the zinc oxide layer, in addition to the above dielectric material and the oxide semiconductor material other than, can also contain MgF₂ , SiO₂ And the like. For example, if the containing SiO₂ , Then the zinc oxide-containing layer is easy to become amorphous, organic EL element flexible easily increase.

In addition, from the inhibit 1st electrode 102 when silver agglomeration of the film, the thickness of the obtained thin uniform 1st electrode 102 of perspective, in the zinc oxide layer preferably contains zinc oxide as the main component. A layer of zinc oxide contained in the amount of the zinc atoms of zinc oxide layer formed throughout the atomic number, is preferably 0.1 - 50 at %, more preferably 0.5 - 50 at %.

On the other hand, if the amount of excess zinc atoms, it is difficult to uniformly form a zinc oxide layer, sometimes transparency will reduce. 1st electrode 102 contained in the variety of various atoms, its content for example by XPS method specific.

The thickness of the zinc oxide layer usually is preferably 3 - 35 nm, more preferably 5 - 25 nm. Zinc oxide layer has a thickness of 3 nm above, 1st electrode 102 of fully improve the film. On the other hand, of the zinc oxide layer has a thickness of 35 nm below, to the organic EL element has little influence on the optical characteristics, the organic EL element of light transmissive difficult to reduce. The thickness of the zinc oxide layer through the ellipsometer to carry out determination.

1st electrode 102 is characterized in that, through a film on a substrate layer, even in the 1st electrode 102 after forming the high-temperature annealing treatment and the like is not carried out, has sufficient conductivity, but according to need after forming a film of high-temperature annealing treatment and the like.

Formed on the substrate of Ag as the main component to the 1st electrode 102 under the condition of, attached with the substrate on the surface diffusion of Ag atoms occurs, at the same time generates a certain size of block (nuclear). Moreover, the early stage of the film growth along the block around the (nuclear) of. Therefore, in forming the initial in the film, a gap exists between the block, can not be turned on. If the block from this state a further growth, a thickness 15 μm the left and the right, is connected between a part of the block, barely turned on. However, the surface of the film is not smooth, easy to generate plasma absorption.

By contrast, in the pre-form containing to the silver forming a growth nucleus of become Pd, Al, Ti, Pt, Mo and the like when the metal of the layer as the layer, to form the 1st electrode 102 of metallic material such as Ag is not easy to move on the substrate layer. In addition, the Pd and the like in the case of the metal atoms, can make the growth nucleus each other interval than the surface diffusion of Ag molecule formed by narrow intervals between the blocks. Therefore, when the Ag layer to the Pd on the growth of the core is the starting point for the growth, even if the thickness of the thin, flat layer may also become easy.

In addition, for example, can adopt the following structure: in use containing a nitrogen atom of the compound to form the substrate layer comprising silver or arranged on the silver as the main component of the alloy of the 1st electrode 102. Therefore, the basal layer formed at the upper part 1st electrode 102 when, form the 1st electrode 102 of the layer of silver atom with a compound containing a nitrogen atom of the interaction, silver atom on the surface of the substrate layer to reduce the diffusion distance, the agglomeration of the silver can be inhibited.

In addition, a layer of zinc oxide contained in the zinc atom and 1st electrode 102 of silver of high affinity. Therefore, in the 1st electrode 102 of the film, to form the 1st electrode 102 of silver is not easy to condense on the zinc oxide layer, can be formed thin and uniform thickness of the 1st electrode 102. In addition, the zinc atoms with the 1st electrode 102 contained in the silver high affinity, therefore, can inhibit the high-humidity environment of the moisture causes the agglomeration of the silver, silver corrosion.

Namely, in general, the adoption of the nuclear growth type (Volumer - Weber: VW-type) allowing the silver particle is easy to isolate the island of silver in the film, by using the above substrate layer, film-forming of the agglomeration of the silver can be inhibited. Therefore, by including silver or silver as the main component of the alloy of the 1st electrode 102 in the film, through the single layer growth type (Frank - van der Merwe: FM type) for film growth. Therefore, as noted above, includes silver or silver as the main component of the alloy of the 1st electrode 102 through more thin layer thickness to ensure that the conductivity, can have 1st electrode 102 of the conductivity improving and light transmissive improved.

[Intermediate electrode]

In the organic EL element, in the 1st light-emitting unit 103, 2nd light-emitting unit 105, 3rd light emitting unit 107 and 4th light emitting unit 109 by the 1st is arranged between the intermediate electrode 104, 2nd intermediate electrode 106 and 3rd intermediate electrode 108 forming the intermediate electrode. These intermediate electrode optimal level of absorption of the component and the reflection components is less and the light transmission is large.

As the intermediate electrode, such as can be used with the above-mentioned 1st electrode 102 the same structure. For example, can use the 2 - 15 nm of silver or silver as the main component of the alloy. In forming silver or silver as the main component of the alloy as the intermediate electrode of the circumstances, may be formed on the above-mentioned base layer. Or may be directly formed on the light-emitting unit such as an electron transport layer on the organic material layer.

In addition, as the intermediate electrode, for example can be used 5 nm - 20 nm of aluminum and the like. In addition, can also adopt the aluminum and the above-mentioned silver laminated structure formed by laminating other conductive material and the structure of the.

In addition, as the intermediate electrode, use can be made of ITO (indium tin oxide), IZO (indium-zinc-oxide), ZnO₂ , TiN, ZrN, HfN, TiO_x , VO_x , CuI, InN, GaN, CuAlO₂ , CuGaO₂ , SrCu₂ O₂ , LaB₆ , RuO₂ Other conductive inorganic compound layer, Au/Bi₂ O₃ Of such as 2 layer film, SnO₂ /Ag/SnO₂ , ZnO/Ag/ZnO, Bi₂ O₃ /Au/Bi₂ O₃ , TiO₂ /TiN/TiO₂ , TiO₂ /ZrN/TiO₂ Such multi-layer film, and C₆₀ The fullerene such as vinyl, oligothiophene or other conductive organic material layer, metal phthalocyanine, metal-free phthalocyanine, metal porphyrin class, metal-free porphyrin class or other conductive organic compound layer and the like.

[2nd electrode]

2nd electrode 110 is a light-emitting unit to the 4th 109 supply such as electronic function, and as a transparent electrode relative to the 3rd middle electrode 108 is a counter electrode of the electrode film. For example, 2nd electrode 110 to use the work function is small (4 eV following) metal (referred to as the electronic pours into the nature metal), alloy, conductive compound and their mixture as the material of the electrode material.

As 2nd electrode 110 of the number of sheet resistance preferably Ω / sq. Following, the film thickness is a generally 10 nm - 5 μm range, preferably 50 - 200 nm selected in a range.

As a specific example of the electrode substances, can be cited sodium, sodium - potassium alloys, magnesium, lithium, magnesium/copper mixture, magnesium/silver mixture, magnesium/aluminum mixture, magnesium/indium mixture, aluminum/alumina (Al₂ O₃ ) Mixture, indium, lithium/aluminum mixture, rare-earth metal and the like.

Wherein the electronic pours into the nature and to from the durability of the oxidation point of view, preferably electronic pours into the nature metal with the work function than the electronic pours into the nature metal is large and stable metal that 2nd metal mixture, such as the magnesium/silver mixture, magnesium/aluminum mixture, magnesium/indium mixture, aluminum/alumina (Al₂ O₃ ) Mixture, lithium/aluminum mixture, aluminum and the like.

2nd electrode 110 can be through the use of vapor deposition or sputtering method and the like are formed of electrode material film to make.

[Light-emitting unit]

1st light-emitting unit 103, 2nd light-emitting unit 105, 3rd light emitting unit 107 and 4th light emitting unit 109 contains at least one of illuminating organic material, send out the white, red, green or blue light of the luminescent layer, but also can be used in the emitting layer and the electrodes is arranged between the other layer.

As the 1st light-emitting unit 103, 2nd light-emitting unit 105, 3rd light emitting unit 107 and 4th light emitting unit 109 of the representative element structure, can cite of the following structure, but is not limited to these.

(1) anode/light emitting layer/cathode

(2) anode/light emitting layer/electron injection layer/cathode

(3) anode/hole transport layer/light emitting layer/cathode

(4) anode/hole transport layer/light emitting layer/electron injection layer/cathode

(5) anode/hole transport layer/light emitting layer/electron transport layer/electron injection layer/cathode

(6) anode/hole injection layer/hole transport layer/light emitting layer/electron injection layer/cathode

(7) anode/hole injection layer/hole transport layer/light emitting layer (electronic stopper layer /) (hole stopper layer /)/electron transport layer/electron injection layer/cathode

In the above, it is preferred to use (7) of the structure, but is not limited to this.

The representative element in the structure, in addition to the anode and the negative pole layer is illuminating light-emitting unit.

(Light-emitting unit)

In the above-mentioned structure, the luminescent layer is single-layer or multi-layer form. In the luminescent layer is a multi-layer of cases, also can be used in the luminescent layer is arranged between the intermediate non-luminescence.

In addition, according to need, can be arranged between the light emitting layer and the cathode of the electron stop layer (hole blocking layer) or the electron injection layer (cathode buffer layer) and, in addition, can also be arranged between the light emitting layer and the anode (the electron barrier layer) electronic stop layer or a hole injection layer (anode buffer layer) and the like.

The electronic transporting layer is has a conveying electronic function of the layer. The electronic transporting layer in a broad sense also include electron injection layer and the layer of the cavity. In addition, the electronic transporting layer can also be formed by a plurality of layers.

A hole transfer layer has the function of conveying the cavity layer. A hole transfer layer in a broad sense also includes a hole injection layer and electronic stopper layer. In addition, a hole transfer layer can also be formed by multi-layer.

[Light-emitting layer]

Preferably the luminescent layer containing as the luminescent material in the phosphorescent light-emitting compound. In addition, the light emitting layer may mixing a plurality light-emitting material, in addition, may also be phosphorescent light-emitting material and a fluorescent light emitting material (fluorescent dopant, fluorescent compound) mixed to the same used in a luminescent layer. As the composition of the luminescent layer, preferably containing a host compound (such as the light-emitting body), light-emitting material (light-emitting dopant), the light-emitting material by light-emitting. The light emitting layer may by for example a vacuum vapor deposition method, a spin coating method, casting method, LB method, ink jet known thin film forming method to the light-emitting material and subjectivization compound to form a film.

As a luminescent layer, as long as the light emitting material containing the light-emitting elements meet, its structure is not particularly limited. The luminescent layer is from the electrode or the electronic transporting layer injection electronic and from the hole transport layer is injected into the cavity and then the combination of the light-emitting layer, the light-emitting part of the luminescent layer can be a layer, can also be the light-emitting layer is adjacent to the layer of the interface. In addition, with the same light-emitting spectrum and light-emitting maximum wavelength layer can be provided with a multi-layer. In this case, in the luminescent layer can also have between the auxiliary layer of the non-luminescence.

The sum of the thickness of the luminescent layer is preferably of 1 - 100 nm range, can be obtained from the more low driving voltage point of view, more preferably in the 1 - 30 nm range. In the use of the laminated multi-layer structure formed by under the condition of a luminescent layer, as the layer thickness of the luminescent layer, preferably is adjusted to 1 - 50 nm range, more preferably is adjusted to 1 - 20 nm range. In addition, the layer thickness of the luminescent layer is means the sum of: the light emitting layer between the intermediate layer of the non-luminescence cases also the layer thickness of the intermediate layer.

(1) host compound

As in the luminescent layer contains the host compound, preferably room temperature (25 °C) of the phosphorescent light-emitting phosphorescent quantum yield is lower than 0.1 of the compound. More preferably the phosphorescent quantum yield less than 0.01. In addition, it is contained in a light emission in the case of the compound, preferably in the layer of volume ratio of 50% or more.

As the host compound, can be used individually known subjectivization compound, or the use of a plurality of host compound. Through the use of a plurality of host compound, can adjust the movement of electric charges, the organic EL element can be high efficiency which. In addition, through the use of a plurality of last-mentioned light-emitting material, can be mixed-different light-emitting, therefore, arbitrary color can be obtained.

(2) the light-emitting material

As the luminescent material, can be cited phosphorescent compound (phosphorescent compounds, phosphorescent light-emitting materials) and fluorescent compounds of the (fluorescent compound, a fluorescent light emitting material).

(Phosphorescent compound)

Phosphorescent compound refers to the observation from the excited triplet state of the light-emitting compound, specifically, is defined as a room temperature (25 °C) is carried out under the phosphorescent light-emitting compound, namely the phosphorescent quantum yield in the 25 °C is under 0.01 more than one compound, the preferred phosphorescent quantum yield is 0.1 or more.

The phosphorescent quantum yield can adopt the article 4 version of the experimental chemical talks 7 II of splitting of the 398 page (1992 and bank, Maruzen) recorded in the method of determination. In phosphorescent quantum yield in the solution can be used to determine the various solvent, in the use of the phosphorescent compound, in any of any kind in the solvent, as long as realizing the above-mentioned phosphorescence quantum yield (0.01 or more) can be.

Phosphorescent compounds can be from the organic EL element of the light-emitting layer use the appropriate choice in the use of known compounds. Preferably containing the periodic table 8 - 10 group of the metal complex compounds, more preferably iridium compound, heterogeneously, platinum compound (platinum complex compounds) or rare earth complex, the most preferred iridium compound.

At least one light-emitting layer can contain 2 or more phosphorescent compounds, can also be of in the luminescent layer the concentration ratio of the phosphorescent compound in the light-emitting layer in the thickness direction of the change in the mode. Preferably the total amount of relative to the luminescent, phosphorescent compound is 0.1 volume % or more and less than 30 volume %.

(Fluorescent luminescent compound)

As fluorescent luminescent compound, coumarin pigment can be cited, -type pigment, flower lush type pigment, croconic acid (croconium) such pigment, party acid pigment, oxo benzene and anthracene pigment, fluorescent Pyridoxine pigment, if ming lei pigment, pyran onium pigment, pigment [...], 1, 2 - diphenylethylene pigment, poly thiophene pigment or rare earth complex derivatives of the phosphor.

[Injection layer: the hole injection layer, an electron injecting layer]

Injection layer is in order to reduce drive voltage, the light-emitting brightness and fix the electrode between the luminescent layer, in "organic EL element and its industrial forefront (issued 30 November 1998 NTS agencies)" section 2 of part 2 Chapter "electrode material" (123 - 166 page) are documented in the, includes a hole injection layer and electron injection layer.

Injection layer can be set according to the requirement. If is the hole injection layer, can be present in the anode (anode) and the luminescent layer or the hole transporting layer, if the electron injection layer, can be present in the cathode (cathode) and the luminescent layer or electron injection layer between.

The electron injection layer is preferably formed from a very thin film of the layer, although depending on the raw material, but its thickness is preferably 1 nm - 10 μm range.

[Hole transport layer]

A hole transfer layer having the function of conveying the cavity of a hole transporting material, a hole injecting layer in a broad sense, the electronic layer of the conveying layer also included in the cavity. A hole transfer layer can be provided with a single-layer or multi-layer. In addition, a hole transfer layer also can be composed of one or two or more kinds of material with a layer of the structure. A hole transfer layer thickness without special restrictions, but is usually 5 nm - 5 μm of the left and right, is preferably 5 - 200 nm range.

As a hole transporting material, has the hole injection or delivery function, the electronic barrier function of any type of material, can be organic, inorganic matter of any kind. In addition, the material of the hole transport layer can be doped in the impurity to improve sexual p. If improve hole transport layer p sex, can realize the production of more power consumption lower component, so preferred.

A hole transfer layer can be through the hole transporting material using for example includes the vacuum vapor deposition method, a spin coating method, casting method, an ink jet printing method of, LB method such as the well-known method to form the thin film.

[Electronic transport layer]

The electronic transporting layer is has the e-function of the material, the broadest sense of the electron injection layer, a hole stopping layer (omit the graphic) also includes the electron transmission layer. An electron transport layer may be arranged as a single-layer structure or a multi-layer laminated structure. In addition, electron injection layer can be composed of one or 2 or more kinds of material of 1 layer structure. The electronic transporting layer thickness without any particular limitation, but is usually 5 nm - 5 μm of the left and right, is preferably 5 - 200 nm range.

In the single-layer structure of the electron transport layer and electron injection layer in the laminated structure, as with the light-emitting layer is adjacent to a portion of the layers of the electronic transporting material (as the hole prevent the material), as long as the transfer from the cathode to the luminescent layer has the electronic function of injected into the can. As this kind of material, of the prior known compound can be from any of the selected material to use.

In addition, as the electron transport layer material (electron-transporting compound), can be used to form the base layer of the compound containing a nitrogen atom. This is used as the electron injection layer as in the electronic transmission, can be used with the same material as the base layer of the above-mentioned material.

The electronic transporting layer by using the material for example includes the vacuum vapor deposition method, a spin coating method, casting method, an ink jet printing method of, LB method such as the well-known method to form a thin film.

[Stopper layer: hole stopper layer, electronic stopper layer]

As noted above, prevent the level eliminates organic compound thin film in addition to the basic structure of the layer, arranged according to the need. For example includes records in Japan extra flat 11 - 204258 Bulletin, Japanese extra flat 11 - 204359 Bulletin and "organic EL element and its industrial forefront (issued 30 November 1998 NTS agencies)" of the 237 in the pages of the hole blocking (holeblocking) layer and the like.

The so-called hole stopper layer, broadly, with the function of the electronic transporting layer. Hole blocking layer having the function of delivering electronic capability and the delivery hole of the small hole blocking material, through the conveying electronic and cavities, can make the electronic with the cavity raises the probability of re-integration. In addition, according to the needs of electronic transport layer as a cavity structure to prevent use. Hole stopping layer is preferably disposed adjacent to the light-emitting layer.

On the other hand, the so-called electronic stopper layer, broadly, has the function of a hole transfer layer. Electronic stop layer has the function of conveying the cavity by conveying the electronic capability and small material, through the conveying and hole prevent electronic, electronic device can be improved and the electron recombination probability. In addition, according to the needs of the hole transport layer as a stop layer to use electronic structure. As is suitable for the layer thickness of the electron stop layer, is preferably 3 - 100 nm range, more preferably 5 - 30 nm range.

" 2. The display device of the embodiment of the 2nd "

Secondly, to field sequential mode of the display device a description of 2nd embodiment. 2nd embodiment only the back light source of the organic EL element of the structure and the 1st embodiment different. Therefore, in the following description, only the structure of the organic EL element description, omits the display panel and the structure of the various structure and repeated in the description.

Figure 2 2nd embodiment of said sequential mode of the display device of the diagrammatic drawings. Figure 2 shown in sequential mode of the display device has a display panel 200 and by the organic electroluminescence element (organic EL element) of the backlight 100 A.

In fig. 2 is shown in the display device of the sequential manner, form the source 100 A with the light emitting part of the organic EL element has along the thickness direction (the outgoing direction of the) laminated 4 layer into the light-emitting unit of the so-called 4 layer stack structure. And, 1st light-emitting unit 103 A with yellow (YL) is a color of the light-emitting unit. In addition, 1st electrode 102, 1st intermediate electrode 104, 2nd light emitting unit 105, 2nd intermediate electrode 106, 3rd light emitting unit 107, 3rd intermediate electrode 108, 4th light-emitting unit 109 and 2nd electrode 110 of the structure is the same as the structure of the 1st embodiment.

Dispose in the closest to the light exit surface of the light-emitting unit on one side of the 1st 103 A with YL of under the condition that the light-emitting unit, can be obtained "in the above-mentioned 1st light-emitting unit of the light-emitting unit with W" 1st embodiment of the same effect. The light-emitting unit by configuring the 1st 103 A, with R and G synthesis will be obtained compared to the case of the YL, is not easy to be caused by the absorption of the laminated structure of the influence of brightness is reduced. Therefore, YL injection can not be hampered by the other light-emitting unit, thereby obtaining a more high brightness.

In particular, because of having the light emitting efficiency than the R, G, B higher YL light-emitting unit, so that the emitted light of the YL will not be hindered by the other light-emitting unit, higher brightness can be obtained. Therefore, the organic EL element of the light-emitting efficiency is improved. Therefore, by means of the 1st YL cleared with light-emitting unit 103 A, back light source of the light-emitting efficiency is improved, can realize the fluctuation.

In addition, in the organic EL element, the light-emitting YL as long as the light-emitting unit is disposed closest to the light exit surface on one side, with regard to the R, G, B of each of the light emitting unit of the configuration, can be designed into a random structure. In addition, as R, G, B and YL 1st of the light-emitting unit 103 A, 2nd light emitting unit 105, 3rd light emitting unit 107 and 4th light emitting unit 109 of the detailed structure, can be applied with the above-mentioned 1st embodiment of each of the light emitting unit of the same structure.

" 3. Time diagram "

Secondly, Figure 3 represents an organic EL element of the equivalent wiring diagram and time diagram.

The clamping 1st will light-emitting unit 103, 2nd light-emitting unit 105, 3rd light emitting unit 107 and 4th light emitting unit 109 of a group of electrodes (Figure 1 or Figure 2 shown in the 1st electrode 102, 1st intermediate electrode 104, 2nd intermediate electrode 106, 3rd intermediate electrode 108 and 2nd electrode 110) connected in parallel. In this, as one example, the light-emitting unit to the 1st 103 emit a white light (W) or yellow light (YL), 2nd light emitting unit 105 sends the red (R), 3rd light-emitting unit 107 emits blue light (B), 4th light emitting unit 109 to send out green (G) a description of the situation.

Figure 3 is shown that the time profile of the driving time of the display panel and the backlight source of the organic EL element of the light-emitting unit of the light-emitting timing of the Figure. Said organic EL on the area (pixel) for sequentially driving the R, G, B and W (or YL) field of the form 1 frame of Vr, Vg, Vb, Vw (or Vyl) of the drive pulse of the time diagram.

The light-emitting unit which is connected to a R, G, B, W (YL) of the time-color, for example the 1 frame of the 4 divided (1/4 frame) issued by the respective colors. And, the display panel with each of the three primary colors of a color synchronously to the time division light-emitting of the light shading, are sequentially formed is time division of the color field Image [R field, G field, B field, W (YL) field].

Then, through being time division of the color of the field Image in time color blending, forming a frame Image.

In addition, in the above-mentioned time in the Figure, each R, G, B and W (YL) of each of the light emitting unit of the light-emitting period of the situation with the same ratio described, but each of the light emitting unit of the light-emitting during the rates may also be changed arbitrarily.

In particular, through the service life of each light-emitting unit according to the adjust the R, G, B and W (YL) of the light-emitting period, the long life of the backlight can be realized. At this time, it is preferred that the aging deterioration is relatively large (short service life) of the light-emitting unit of the light-emitting period than other light-emitting the unit is long. For example, it is preferred that the SPAN of the light emitting unit of the light-emitting during most of the long. Therefore, can suppress the aging deterioration of the back-light source of the reducing of the luminance or chrominance changes, reliability of the display device is improved.

W Image signal (gradation degree data) generation method is as follows.

The R, G, B Image signal in the Image signal as the minimum of the M gradation, the Image signal is α × M W (α is 0 above 1 the following multiplier). Constant α is 1 when the minimum power consumption, but from the beautiful perspective, the 0.8 the left and the right of the value.

YL are in the same situation, will be R, G Image signal in the Image signal as the minimum of the N gradation, the Image signal is the β × N YL (β is 0 above 1 the following multiplier). Constant β is 1 when the minimum power consumption, but from the beautiful perspective, the 0.8 the left and the right of the value.

[Effect]

In the above-mentioned 1st and 2nd embodiment embodiment of the display device in sequential manner, dispose in the light of the most close to a side of the light-emitting unit having a plurality of 1st YL W or a color of the light-emitting unit. By means of the with W or YL with a color of the light emitting unit, and only use the R, G, B this 3 compared with the color of the light-emitting light of, is not susceptible to such absorption by a laminated structure. Therefore, higher brightness can be obtained. Therefore, the organic EL element of the light-emitting efficiency is improved, can realize the low power consumption of the backlight source fluctuation. And, can realize the field sequential mode fluctuation of the display device.

In addition, the invention is not limited to the embodiment example described in structure, without isolation from the rest of the structure of the invention can be carried out within the scope of the deformation, the alteration.