JP4091021B2 - Active matrix type display device - Google Patents

Description

  The present invention relates to a light-emitting device using a light-emitting element in which fluorescence or phosphorescence is obtained by applying an electric field to an element in which a film containing an organic compound (hereinafter referred to as an “organic compound layer”) is provided between a pair of electrodes. It relates to a manufacturing method thereof. Note that the light-emitting device in this specification refers to an image display device, a light-emitting device, or a light source. Also, modules with light-emitting elements such as connectors such as FPC (Flexible printed circuit) or TAB (Tape Automated Bonding) tape or TCP (Tape Carrier Package), modules with a printed wiring board at the end of TAB tape or TCP In addition, a module in which an IC (integrated circuit) is directly mounted on a light emitting element by a COG (Chip On Glass) method is included in the light emitting device.

  The light emitting element as used in the field of this invention is an element light-emitted by applying an electric field. The light emission mechanism is such that when a voltage is applied with an organic compound layer sandwiched between electrodes, electrons injected from the cathode and holes injected from the anode recombine in the organic compound layer, and excited molecules (Hereinafter referred to as “molecular excitons”), and when the molecular excitons return to the ground state, they are said to emit energy and emit light.

  In such a light emitting device, the organic compound layer is usually formed as a thin film having a thickness of less than 1 μm. Further, since the light emitting element is a self-luminous element in which the organic compound layer itself emits light, a backlight as used in a conventional liquid crystal display is not necessary. Therefore, it is a great advantage that the light-emitting element can be manufactured to be extremely thin and light.

  For example, in an organic compound layer of about 100 to 200 nm, the time from carrier injection to recombination is about several tens of nanoseconds considering the carrier mobility of the organic compound layer. Even if the process from light emission to light emission is included, light emission occurs in the order of microseconds or less. Therefore, one of the features is that the response speed is very fast.

Note that since the light emitting element is a carrier injection type element, it can be driven with a DC voltage (DC driving), and noise hardly occurs. Regarding the driving voltage, the thickness of the organic compound layer is first made to be a uniform ultra-thin film of about 100 nm, and electrode materials that reduce the carrier injection barrier for the organic compound layer are selected, and further, a heterostructure (laminated structure) is formed. There is a report that a sufficient luminance of 100 cd / m ² has been achieved at 5.5 V (Non-patent Document 1).

  Due to these characteristics such as thin and light weight, high-speed response, and direct current low voltage drive, the light emitting element is attracting attention as a next-generation flat panel display element. Further, since it is a self-luminous type and has a wide viewing angle, the visibility is relatively good, and it is considered to be effective as an element used for a display screen of an appliance.

  However, in such a light-emitting element, when direct current driving in which a bias in a certain direction is always applied to the organic compound layer is used, charge is accumulated in the organic compound layer, which causes a problem that luminance decreases.

  In this regard, there is a report that a decrease in luminance can be suppressed by inserting a hole injection layer between the anode and the hole transport layer and further using a rectangular wave AC drive instead of a DC drive (non- Patent Document 2).

  This is because the energy barrier is reduced by inserting a hole injection layer, and voltages having different polarities are alternately applied to the organic compound layer by alternating current drive, so that the accumulation of charges inside the organic compound layer is reduced. Therefore, it is experimental support that a reduction in luminance can be suppressed, and suggests that AC driving is suitable for improving the element lifetime of the light emitting element.

C. W. Tang and S. A. VanSlyke, "Organic electroluminescent diodes", Applied Physics Letters, vol. 51, No. 12, 913-915 (1987)

S. A. VanSlyke, C. H. Chen, and C. W. Tang, "Organic electroluminescent devices with improved stability", Appl. Phys. Lett., 69, (15) 2160-2162 (1996)

  However, in the case of forming a light emitting element by alternating current drive, a positive voltage (forward bias) is applied from the anode side because the light emitting element usually has a laminated structure including an anode, an organic compound layer, and a cathode. Only when a negative voltage (reverse bias) is applied to the cathode side, current flows and light emission is obtained. That is, when AC driving is used, the light emitting element does not emit light when a reverse bias is applied.

  As described above, since the display becomes dark when the effective light emission time is shortened, when a high voltage is applied to maintain a predetermined luminance, there arises a problem that the deterioration of the light emitting element proceeds.

  Accordingly, an object of the present invention is to provide a light-emitting element that can always emit light regardless of whether alternating current driving is used as a driving method of a light-emitting device and voltages having different polarities are alternately applied, and a manufacturing method thereof. To do.

    In the present invention, a first light-emitting element and a second light-emitting element including an anode, an organic compound layer, and a cathode are formed. The light-emitting element includes an anode and a cathode sandwiching the same organic compound layer. The anode of the first light emitting element and the anode of the second light emitting element, and the cathode of the first light emitting element and the cathode of the second light emitting element are formed on opposite sides of the organic compound layer, respectively. One gradation display is performed by one of the first light-emitting element and the second light-emitting element.

  Note that the light-emitting device of the present invention causes a light-emitting element to emit light by AC driving, and reverse polarity voltages are alternately applied to the first light-emitting element and the second light-emitting element. One light emitting element to which a positive polarity voltage (forward bias) is applied emits light, and the other light emitting element to which a negative polarity voltage (reverse bias) is applied does not emit light. That is, since the two light emitting elements emit light alternately depending on the polarity of the applied voltage, the light emitting element can always emit light.

  Since the light-emitting device of the present invention can alleviate charge accumulation in the organic compound layer by alternating current drive, it can suppress a decrease in luminance and improve element lifetime. Furthermore, since the light emitting device of the present invention can always emit light from the light emitting element of the pixel even in the case of AC driving, it is possible to prevent element deterioration in DC driving, while at the same gradation as in the case of DC driving. Display is possible.

  The structure of the invention disclosed in the present invention is a light-emitting device including a first light-emitting element and a second light-emitting element, and the first light-emitting element includes a first pixel electrode, an organic compound layer, A first counter electrode, and the second light-emitting element includes a second pixel electrode, the organic compound layer, and a second counter electrode. The second counter electrode is either an anode or a cathode, and the second pixel electrode and the first counter electrode are either the anode or the cathode. .

  According to another aspect of the present invention, there is provided a first TFT and a second TFT formed on an insulating surface, an interlayer insulating film formed on the first TFT and the second TFT, and the interlayer A first pixel electrode and a second pixel electrode formed on an insulating film; a connection portion between the first pixel electrode and the first TFT; and a second pixel electrode and the second TFT. An insulating film formed so as to cover the connection portion, an organic compound layer formed on the first pixel electrode and the second pixel electrode, and a first counter electrode formed on the organic compound layer , And a second counter electrode, wherein the first pixel electrode and the second counter electrode are either an anode or a cathode, and the second pixel electrode, And the first counter electrode is either the anode or the cathode A light emitting device according to claim Rukoto.

  In each of the above structures, the first and second TFTs formed on the insulating surface, the interlayer insulating film formed on the first TFT and the second TFT, and the interlayer insulating film The first pixel electrode and the second pixel electrode formed above, the connection portion between the first pixel electrode and the first TFT, and the connection between the second pixel electrode and the second TFT An insulating film formed over the portion, an organic compound layer formed on the first pixel electrode and the second pixel electrode, a first counter electrode formed on the organic compound layer, and A light emitting device having a second counter electrode, wherein the first TFT and the second TFT each have a source region and a drain region, and the first pixel electrode comprises the first electrode. , The second pixel electrode includes the second electrode and the first electrode The first electrode and the second electrode are electrically connected to either the source region or the drain region at the opening formed in the interlayer insulating film, 1 pixel electrode and the second counter electrode are either an anode or a cathode, and the second pixel electrode and the first counter electrode are either an anode or a cathode. A light emitting device characterized by the above.

  In each of the above structures, the first and second TFTs formed on the insulating surface, the interlayer insulating film formed on the first TFT and the second TFT, and the interlayer insulating film The first pixel electrode and the second pixel electrode formed above, the connection portion between the first pixel electrode and the first TFT, and the connection between the second pixel electrode and the second TFT An insulating film formed over the portion, an organic compound layer formed on the first pixel electrode and the second pixel electrode, a first counter electrode formed on the organic compound layer, and A light emitting device having a second counter electrode, wherein the first TFT and the second TFT each have a source region and a drain region, and the first pixel electrode comprises the first electrode. , The second pixel electrode includes the second electrode and the first electrode The first electrode and the second electrode are electrically connected to either the source region or the drain region at the opening formed in the interlayer insulating film, The first electrode and the second electrode are made of a material that forms either the anode or the cathode, and the first auxiliary electrode is made of a material that forms the other of the anode or the cathode. It is a light-emitting device.

  In each of the above structures, the first and second TFTs formed on the insulating surface, the interlayer insulating film formed on the first TFT and the second TFT, and the interlayer insulating film The first pixel electrode and the second pixel electrode formed above, the connection portion between the first pixel electrode and the first TFT, and the connection between the second pixel electrode and the second TFT An insulating film formed over the portion, an organic compound layer formed on the first pixel electrode and the second pixel electrode, a first counter electrode formed on the organic compound layer, and A first counter electrode including a second auxiliary electrode and a third electrode, and a second counter electrode including a third electrode, wherein the first counter electrode includes the second counter electrode. The pixel electrode and the second counter electrode are either anodes or cathodes. While in and either the second pixel electrode, and the first counter electrode, a light emitting device, characterized in that the other one of the anode or the cathode.

  In each of the above structures, the first and second TFTs formed on the insulating surface, the interlayer insulating film formed on the first TFT and the second TFT, and the interlayer insulating film The first pixel electrode and the second pixel electrode formed above, the connection portion between the first pixel electrode and the first TFT, and the connection between the second pixel electrode and the second TFT An insulating film formed over the portion, an organic compound layer formed on the first pixel electrode and the second pixel electrode, a first counter electrode formed on the organic compound layer, and A light emitting device having a second counter electrode, wherein the first counter electrode includes a second auxiliary electrode and a third electrode, the second counter electrode includes a third electrode, The electrode is made of a material that forms either the anode or the cathode. The second auxiliary electrode is a light-emitting device characterized by comprising the material forming the other one of the anode or the cathode.

  In each of the above structures, the organic compound layer is made of a bipolar material having a hole transporting property and an electron transporting property.

  Note that in manufacturing the light-emitting device of the present invention, the first electrode and the second electrode are formed, the first auxiliary electrode is formed only on the second electrode by vapor deposition, and then the same is formed on these electrodes. The organic compound layer which consists of the same layer can be formed with this material.

  Therefore, in another configuration of the present invention, the first electrode and the second electrode are formed on the insulating surface, the first auxiliary electrode is formed on the second electrode, the first electrode, An organic compound layer is formed on the second electrode and the first auxiliary electrode, and a second auxiliary electrode is formed on the organic compound layer at a position overlapping the first electrode, and the organic compound And a method of manufacturing a light-emitting device in which a third electrode is formed over the second auxiliary electrode, the first pixel electrode including the first electrode, the organic compound layer, and the second A first light-emitting element having a first counter electrode composed of the auxiliary electrode and the third electrode, a second pixel electrode composed of the second electrode and the first auxiliary electrode, A second counter electrode comprising the organic compound layer and the third electrode; A method for manufacturing a light-emitting device, which comprises forming a light emitting element.

  According to another configuration of the present invention, a first TFT and a second TFT are formed on an insulating surface, an interlayer insulating film is formed on the first TFT and the second TFT, and the interlayer insulation is formed. A first electrode and a second electrode are formed on the film; a first auxiliary electrode is formed on the second electrode; a connecting portion between the first electrode and the first TFT; An insulating film is formed to cover a connection portion between the second electrode and the second TFT, an organic compound layer is formed on the first electrode, the second electrode, and the first auxiliary electrode, A second auxiliary electrode is formed on the organic compound layer at a position overlapping with the first electrode, and a third electrode is formed on the organic compound layer and the second auxiliary electrode. A manufacturing method comprising: a first pixel electrode including the first electrode; and the organic compound layer A first pixel having a first counter electrode comprising the second auxiliary electrode and the third electrode; and a second pixel comprising the second electrode and the first auxiliary electrode. A method for manufacturing a light-emitting device, comprising: forming a second light-emitting element having an electrode, the organic compound layer, and a second counter electrode including the third electrode.

  Note that in the above structure, the first TFT and the second TFT each have a source region and a drain region, and the first electrode and the second electrode are formed in the interlayer insulating film. The opening is electrically connected to either the source region or the drain region.

  In each of the above structures, the first pixel electrode and the second counter electrode are either an anode or a cathode, and the second pixel electrode and the first counter electrode are an anode or a cathode. The other is the other.

  Note that light emission obtained from the light-emitting device of the present invention includes light emission in one or both of the singlet excited state and the triplet excited state.

  In the present invention, charge accumulation in the organic compound layer, which has been a problem in the case of DC driving, can be prevented by manufacturing an AC driving light emitting device. As a result, the problem of a decrease in luminance of the light emitting element is improved, and thus the element characteristics of the light emitting element can be improved and the life can be extended. In addition, the light emitting device of the present invention is provided with two types of light emitting elements having different structures, and has a structure in which one of the light emitting elements always functions even when voltages having different polarities are applied in AC driving. Therefore, gradation display similar to that in the case of DC driving can be performed.

  Embodiment Modes of the present invention will be described with reference to FIGS. Note that FIG. 1A illustrates an element structure of a light-emitting element included in each pixel in the present invention.

  As shown in FIG. 1A, two types of electrodes, an anode 102 and a cathode 103, are formed on a substrate 101, and an organic compound layer 104 is formed in contact with these electrodes (102, 103). A cathode 105 and an anode 106 are formed in contact with 104. That is, it has a structure in which a cathode and an anode are formed on both sides of the common organic compound layer 104, respectively. In other words, a first light emitting element 107 having an anode 102, an organic compound layer 104, and a cathode 105, and a second light emitting element 108 having a cathode 103, an organic compound layer 104, and an anode 106 are formed. ing.

  In this specification, an electrode formed before the organic compound layer is formed is referred to as a pixel electrode. Specifically, the anode 102 and the cathode 103 are referred to as a pixel electrode (1) and a pixel electrode (2), respectively.

  On the other hand, an electrode formed after the organic compound layer is formed is called a counter electrode. Specifically, the cathode 105 and the anode 106 are referred to as a counter electrode (1) and a counter electrode (2), respectively.

  In these light emitting devices, when a voltage lower than the anode is applied to the cathode and a voltage higher than the cathode is applied to the anode, that is, when a forward bias is applied, electrons are transferred from the cathode to the organic compound layer. The holes are injected and holes are injected from the anode into the organic compound layer, whereby a current flows through the organic compound layer. In the organic compound layer 104, light is emitted by recombination of holes and electrons.

  In the present invention, the organic compound layer 104 has a bipolar property. Note that the bipolar property means that it has transportability for both electrons and holes which are carriers.

  In addition, the two types of light emitting elements (107, 108) in the present invention are connected to an AC power source 109. Then, by alternately inverting the magnitude relationship between the voltages applied to the pixel electrode and the counter electrode, a forward bias is alternately applied to one of the two types of light emitting elements (107, 108), and a reverse bias is alternately applied to the other. Is applied.

  Note that in this specification, a state in which a forward bias is applied to a light emitting element and a current flows is referred to as a function of the light emitting element. That is, when a reverse bias is applied to the light emitting element, the light emitting element does not function.

  A specific method for forming the light-emitting element of the present invention will be described with reference to FIG.

The first electrode 112 and the second electrode 113 are formed over the substrate 101 using a conductive material. Note that in this embodiment, the case where the first electrode 112 and the second electrode 113 are formed using a material that can serve as an anode will be described. As the conductive material used here, a material having a high work function with a work function of 4.5 eV or more can be used. Specifically, in addition to a light-transmitting conductive film such as indium tin oxide (ITO), indium zinc oxide (IZO), or IDIXO (In ₂ O ₃ —ZnO), gold (Au), platinum (Pt), nickel Elements belonging to Group 3 to 11 in the long-period periodic table such as (Ni), tungsten (W), and titanium (Ti) can be used as the conductive material. Note that in the case of an element structure in which light is transmitted from the electrodes (112, 113) formed here, a light-transmitting conductive material is used.

  Next, the first auxiliary electrode 114 is formed over the second electrode 113 using a conductive material that can serve as a cathode. Note that a material having a low work function (specifically, a work function of 3.8 eV or less) used for the first auxiliary electrode 114 is an element belonging to Group 1 or Group 2 of the element periodicity, that is, an alkali metal and an alkali. In addition to earth metals and alloys and compounds containing these, transition metals including rare earth metals can be used. The first auxiliary electrode 114 can be formed by an evaporation method or a sputtering method.

  Next, a bipolar organic compound layer 104 is formed over the first electrode 112 and the first auxiliary electrode 114. Note that a material for forming the organic compound layer 104 may be a low molecular material or a high molecular material.

  When using a low molecular weight material, it is formed by co-evaporating a hole transporting organic compound and an electron transporting organic compound so that the weight ratio (wt%) is 1: 1. Can do.

Specifically, 4,4′-bis [N- (1-naphthyl) -N-phenyl-amino] -biphenyl (hereinafter referred to as α-NPD) having a hole transporting property and an electron transporting property are used. It can be formed by co-evaporating tris (8-quinolinolato) aluminum (hereinafter referred to as Alq ₃ ) having properties. Note that the light-emitting region can be limited by doping a part of the organic compound layer with a material serving as a dopant.

  In the case of using a high molecular weight material, it can be formed by mixing a hole-transporting organic compound and an electron-transporting organic compound in a solvent at a predetermined molar ratio.

  Specifically, it is a polyvinyl carbazole (hereinafter referred to as PVK) having a hole transporting property and a 1,3,4-oxadiazole derivative having an electron transporting property (2- (4-biphenylyl)). It can be formed by applying a coating solution formed by mixing -5- (4-t-butylphenyl) -1,3,4-oxadiazole (hereinafter referred to as PBD) in toluene. It should be noted that a dopant material may be mixed in the coating solution.

  Next, the second auxiliary electrode 115 is formed on the organic compound layer 104 by using a conductive material which becomes a cathode at a position overlapping with the first electrode 112. Note that as the conductive material used here, the same material as that used in forming the first auxiliary electrode 114 can be used. However, since the second auxiliary electrode 115 formed here is formed on the organic compound layer 104, it is preferable to form the second auxiliary electrode 115 by an evaporation method.

  Finally, a third electrode 116 is formed so as to cover the organic compound layer 104 and the second auxiliary electrode 115. Note that as a material for forming the third electrode 116, a conductive material capable of forming an anode is used. However, the material used when the first electrode 112 and the second electrode 113 are formed first is used. The same material can be used. However, since the third electrode 116 formed here is formed over the organic compound layer 104, it is preferable to form the third electrode 116 by a vapor deposition method.

  As described above, the first light-emitting element 117 and the second electrode 113 including the first electrode 112, the organic compound layer 104, the second auxiliary electrode 115, and the third electrode, the first auxiliary electrode 114, the organic A second light-emitting element 118 including the compound layer 104 and the third electrode 116 can be formed.

  Note that in the first light-emitting element 117, the first electrode 112 made of a conductive material that can serve as an anode is the anode 102 in FIG. 1A and the pixel electrode (1). On the other hand, the second auxiliary electrode 115 made of a conductive material that can be used as a cathode can be used as a cathode in terms of work function. Here, the stacked structure of the second auxiliary electrode 115 and the third electrode 116 is the cathode 105 in FIG. 1A, which is the counter electrode (1).

  Further, in the second light-emitting element 118, the first auxiliary electrode 114 made of a conductive material that can be a cathode on the second electrode 113 can be a cathode in terms of work function, but is formed of an extremely thin film. Since the film resistance in question can be lowered by being stacked on the second electrode 113, here, a stack of the second electrode 113 and the first auxiliary electrode 114 is shown in FIG. This is the cathode 103 in A), which is the counter electrode (2). On the other hand, the third electrode 116 made of a conductive material that can serve as an anode is the anode 106 in FIG. 1A and the counter electrode (2).

  Examples of the present invention will be described below.

  In this embodiment, an active matrix type in which a TFT (thin film transistor) and a light emitting element are electrically connected, the pixel electrode of the light emitting element is formed of a light-transmitting material, and light generated in the organic compound layer is used. The case of a structure (so-called downward emission type) that is extracted from the pixel electrode will be described.

  In FIG. 2A, a cross-sectional view of a pixel forming a pixel portion of a light-emitting device is shown. Two types of TFTs (also referred to as current control TFTs) are formed over the substrate 201, and the first electrode 205 is electrically connected to the TFT 1 (202) through the wiring 204, so that the TFT 2 ( 203) is electrically connected to the second electrode (2) 207 via a wiring 206. In this embodiment, the TFT1 (202) is a p-channel TFT, and the TFT2 (203) is an n-channel TFT.

  Note that a connection portion between the wiring 204 and the first electrode 205 and a connection portion between the wiring 206 and the second electrode 207 are covered with an insulating layer 214 made of an insulating material. Note that in forming the insulating layer 214, in addition to a material containing silicon such as silicon oxide, silicon nitride, and silicon nitride oxide, an organic resin film such as polyimide, polyamide, acrylic (including photosensitive acrylic), or BCB (benzocyclobutene) is used. An insulating film is formed using a coated silicon oxide film (SOG: Spin On Glass) as a silicon oxide film. The film thickness can be 0.1 to 2 μm. In particular, when a material containing silicon such as silicon oxide, silicon nitride, and silicon nitride oxide is used, the film thickness is 0.1 to 0.3 μm. It is desirable to form with.

  Then, an opening is formed at a position corresponding to the first electrode 205 and the second electrode 207 of the insulating film, and the insulating layer 214 is formed.

  Specifically, an insulating film having a thickness of 1 μm is formed using photosensitive acrylic, patterning is performed by photolithography, and then an insulating layer 214 is formed by performing an etching process.

  On the first electrode 205, an organic compound layer 209, a second auxiliary electrode 210, and a third electrode 211 are stacked to form a first light-emitting element 212. In addition, a first auxiliary electrode 208, an organic compound layer 209, and a third electrode 211 are stacked over the second electrode 207 to form a second light-emitting element 213.

  Note that the first electrode 205, the second electrode 207, and the third electrode 211 are formed using a material having a high work function that can serve as an anode, and the first auxiliary electrode 208 and the second auxiliary electrode 210 are It is made of a material having a small work function that can serve as a cathode. Therefore, in the first light-emitting element 212, the first electrode 205 serves as the first pixel electrode (anode) 217, and the second auxiliary electrode 210 and the third electrode 211 are stacked. The counter electrode (cathode) 218 is formed. In the second light-emitting element 213, a stack of the second electrode 207 and the first auxiliary electrode 208 serves as a second pixel electrode (cathode) 219, and the third electrode 211 serves as the second electrode. The counter electrode (anode) 220 is formed.

  Specific element structures of the first light-emitting element 212 and the second light-emitting element 213 are illustrated in FIG. 2B, and a manufacturing method thereof will be described below.

  However, TFTs and wirings formed on the substrate are not described in this example until they will be described in detail in a later example, and in this example, manufacturing of a light-emitting element formed after the wiring is formed is described. To do.

  First, a first electrode 205 is formed in contact with the wiring 204, and a second electrode 207 is formed in contact with the wiring 206. Note that the first electrode 205 and the second electrode 207 in this embodiment are light-transmitting electrodes and thus are light-transmitting and are formed using a material having a work function of 4.5 eV or more. Specifically, a material such as ITO, IZO, or IDIXO can be used. Here, ITO is formed to a thickness of 100 nm by a sputtering method and then patterned.

Further, the first auxiliary electrode 208 is formed over the second electrode 207. Note that the first auxiliary electrode 208 is also formed using a light-transmitting material. As a material of the first auxiliary electrode 208 in this embodiment, barium fluoride (BaF ₂ ), calcium fluoride (CaF), cesium fluoride (CsF), or the like can be used, but the film thickness is about 1 nm. Need to form. In addition, cesium (Cs), barium (Ba), calcium (Ca), a magnesium alloy (Mg: Ag), and a lanthanoid-based material can be used. In this case, the film thickness may be 20 nm or less. Here, barium fluoride (BaF ₂ ) is formed to a thickness of 1 nm, and the first auxiliary electrode 208 is formed. Further, the first auxiliary electrode 208 can be formed only on the second electrode 207 by vapor deposition using a metal mask.

  Next, the organic compound layer 209 is formed. In this embodiment, a low molecular weight material is used, and a hole transporting organic compound and an electron transporting organic compound are co-deposited so that the weight ratio (wt%) is 1: 1. can do. In addition, the film thickness of the organic compound layer 209 in this example is 100 nm.

Specifically, 4,4′-bis [N- (1-naphthyl) -N-phenyl-amino] -biphenyl (hereinafter referred to as α-NPD) having a hole transporting property and an electron transporting property are used. It can be formed by co-evaporating tris (8-quinolinolato) aluminum having properties (hereinafter referred to as Alq ₃ ) so that the weight ratio (wt%) is 1: 1. The layer formed here will be referred to as a bipolar layer 215.

Further, in this example, in the course of forming the bipolar layer 215, 4-dicyanomethylene-2-methyl-6- (julolidin-4-yl-vinyl) -4H-pyran (hereinafter referred to as DCM2) which becomes a dopant. ) To form a doped region 216 to be a light emitting region. In addition, it can be formed by co-evaporation so that the weight ratio (wt%) in the doped region 216 at this time is (α-NPD) :( Alq ₃ ) :( DCM) = 50: 50: 1. .

  Then, the light emitting region in the organic compound layer 209 can be limited by forming the bipolar layer 215 again on the doped region 216. Note that in the case where the organic compound layer 209 is formed using such a material, an organic compound layer that emits red light can be formed.

Note that in the case of forming an organic compound layer that emits green light, the bipolar layer 215 is formed by using the same material (α-NPD and Alq ₃ ) and doping the doped region 216 with dimethylquinacridone. it can. In addition, it can be formed by co-evaporation so that the weight ratio (wt%) in the doped region 216 at this time is (α-NPD) :( Alq ₃ ) :( quinacridone) = 50: 50: 1. .

  Further, in the case of forming an organic compound layer exhibiting blue light emission, bathocuproin (hereinafter referred to as BCP) and 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenyl- The bipolar layer 215 is formed by co-evaporating amino] -triphenylamine (hereinafter referred to as MTDATA) so that the weight ratio (wt%) is 1: 1. The doped region 216 can be formed by doping perylene. In addition, it can form by co-evaporating so that the weight ratio (wt%) in the dope region 216 at this time may be (BCP) :( MTDATA) :( perylene) = 50: 50: 5.

  These doped regions 216 are formed with a thickness of 20 to 30 nm.

  By forming the pixel having the organic compound layer that emits red light, the organic compound layer that emits green light, and the organic compound layer 209 that emits blue light as described above in the pixel portion, full-color display is possible.

  In the organic compound layer 209 shown in this embodiment, the doped region 216 is a light emitting region. However, the doped region 216 is not provided, but a light emitting layer made of a completely different material is interposed between the bipolar layers 215. It can also be formed. In this case, the material for forming the bipolar layer 215 may be the one shown above, and the material for forming the light emitting layer may be 4,4′-bis (2,2-diphenyl-vinyl) -biphenyl. (Hereinafter referred to as DPVBi).

On the other hand, when a polymer material is used, PVK and PBD are mixed in toluene at a molar ratio of 1: 0.3, and a dopant tris (2-phenylpyridine) iridium (hereinafter, Ir (ppy) is used. ) ₃ ) is mixed to form a coating liquid by coating so as to have a mole fraction of 3 mol% with respect to the total number of moles of PVK and PBD, and this is formed by coating.

  Next, the second auxiliary electrode 210 is formed on the organic compound layer 209. Note that the second auxiliary electrode 210 can also be formed using the same material as the first auxiliary electrode 208, but here, barium (Ba) is formed to a thickness of 20 nm, and the second auxiliary electrode 210 is formed. Form. Further, the second auxiliary electrode 210 can be formed only on the first electrode 205 by vapor deposition using a metal mask.

  Finally, the third electrode 211 is formed. Note that as a conductive material for forming the third electrode 211, a material having a high work function with a work function of 4.5 eV or more is used. In this embodiment, since it is desirable to have a structure in which light is not emitted from the third electrode 211 in order not to reduce the light emission efficiency of the light emitting element, the light emitting element is formed using a light shielding material. Specifically, an element belonging to Group 3 to 11 in the long-period periodic table such as gold (Au), platinum (Pt), nickel (Ni), tungsten (W), titanium (Ti), etc. is used as a conductive material. Can be used. In this embodiment, the third electrode 211 is formed by depositing gold (Au) with a thickness of 100 nm.

  As described above, a bottom emission type light-emitting device that has the first light-emitting element 212 and the second light-emitting element 213 in one pixel and can emit light from the pixel electrode side in either light-emitting element. Can be formed.

  In the present embodiment, unlike the first embodiment, a case where the counter electrode is formed of a light-transmitting material and light generated in the organic compound layer is extracted from the counter electrode (a so-called upward emission type) will be described.

  FIG. 3A shows a cross-sectional view of a pixel forming a pixel portion of a light-emitting device. Two types of TFTs (also referred to as current control TFTs) are formed over the substrate 301, and the first electrode 305 is electrically connected to the TFT 1 (302) through the wiring 304, so that the TFT 2 ( 303) is electrically connected to the second electrode (2) 307 through the wiring 306. In this embodiment, the TFT1 (302) is formed by a p-channel TFT, and the TFT2 (303) is formed by an n-channel TFT.

  Note that the connection portion between the wiring 304 and the first electrode 305 and the connection portion between the wiring 306 and the second electrode 307 are covered with an insulating layer 314 made of an insulating material as in the first embodiment. Note that as the material for forming the insulating layer 314, a material similar to that shown in Embodiment 1 may be used. Similarly, an opening is formed at a position corresponding to the first electrode 305 and the second electrode 307 of the insulating film, and the insulating layer 314 is formed.

  On the first electrode 305, an organic compound layer 309, a second auxiliary electrode 310, and a third electrode 311 are stacked to form a first light-emitting element 312. In addition, over the second electrode 307, the first auxiliary electrode 308, the organic compound layer 309, and the third electrode 311 are stacked, so that the second light-emitting element 313 is formed.

  Note that the first electrode 305, the second electrode 307, and the third electrode 311 are formed of a material having a high work function that can serve as an anode, and the first auxiliary electrode 308 and the second auxiliary electrode 310 are It is made of a material having a small work function that can serve as a cathode. Therefore, in the first light-emitting element 312, the first electrode 305 becomes the first pixel electrode (anode) 317, and the second auxiliary electrode 310 and the third electrode 311 are stacked. The counter electrode (cathode) 318 is formed. In the second light-emitting element 313, the stack of the second electrode 307 and the first auxiliary electrode 308 serves as a second pixel electrode (cathode) 319, and the third electrode 311 serves as the second pixel electrode 319. The counter electrode (anode) 320 is formed.

  Specific element structures of the first light-emitting element 312 and the second light-emitting element 313 are illustrated in FIG. 3B, and a manufacturing method thereof will be described below.

  However, TFTs and wirings formed on the substrate are not described in this example until they will be described in detail in a later example, and in this example, manufacturing of a light-emitting element formed after the wiring is formed is described. To do.

  First, a first electrode 305 is formed in contact with the wiring 304 and a second electrode 307 is formed in contact with the wiring 306. Note that in this embodiment, in order not to reduce the light emission efficiency of the light-emitting element, it is preferable to have a structure in which light is not emitted from the first electrode 305 and the second electrode 307. Is formed using a material of 4.5 eV or more. Here, titanium nitride (TiN) is formed by sputtering and then patterned to a thickness of 100 nm.

Further, the first auxiliary electrode 308 is formed over the second electrode 307. Note that as the material of the first auxiliary electrode 308 in this embodiment, barium fluoride (BaF ₂ ), calcium fluoride (CaF), cesium fluoride (CsF), or the like can be used, but the film thickness is 1 nm. It is necessary to form with a degree. In addition, cesium (Cs), barium (Ba), calcium (Ca), a magnesium alloy (Mg: Ag), and a lanthanoid-based material can be used. In this case, the film thickness may be 20 nm or less. Here, a magnesium alloy (Mg: Ag) is formed to a thickness of 20 nm, and the first auxiliary electrode 308 is formed. Further, the first auxiliary electrode 308 can be formed only on the second electrode 307 by vapor deposition using a metal mask.

  Next, an organic compound layer 309 is formed. Also in this example, in the same manner as in Example 1, a low molecular weight material is used, and the weight ratio (wt%) of the hole transporting organic compound and the electron transporting organic compound is 1: 1. Thus, it can be formed by co-evaporation. Note that the film thickness of the organic compound layer 309 in this example is 100 nm.

Specifically, 4,4′-bis [N- (1-naphthyl) -N-phenyl-amino] -biphenyl (hereinafter referred to as α-NPD) having a hole transporting property and an electron transporting property are used. It can be formed by co-evaporating tris (8-quinolinolato) aluminum having properties (hereinafter referred to as Alq ₃ ) so that the weight ratio (wt%) is 1: 1. The layer formed here will be referred to as a bipolar layer 315.

Further, in this example, in the course of forming the bipolar layer 215, 4-dicyanomethylene-2-methyl-6- (julolidin-4-yl-vinyl) -4H-pyran (hereinafter referred to as DCM2) which becomes a dopant. ) To form a doped region 316 to be a light emitting region. In addition, it can be formed by co-evaporation so that the weight ratio (wt%) in the doped region 316 at this time is (α-NPD) :( Alq ₃ ) :( DCM) = 50: 50: 1. .

  Then, the light emitting region in the organic compound layer 309 can be limited by forming the bipolar layer 315 again on the doped region 316. Note that in the case where the organic compound layer 309 is formed using such a material, an organic compound layer that emits red light can be formed.

Note that in the case of forming an organic compound layer that emits green light, the bipolar layer 315 may be formed by using the same material (α-NPD and Alq ₃ ) and doping the doped region 316 with dimethylquinacridone. it can. In addition, it can be formed by co-evaporation so that the weight ratio (wt%) in the doped region 316 at this time is (α-NPD) :( Alq ₃ ) :( quinacridone) = 50: 50: 1. .

  Further, in the case of forming an organic compound layer exhibiting blue light emission, bathocuproin (hereinafter referred to as BCP) and 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenyl- Bipolar layer 315 is formed by co-evaporating amino] -triphenylamine (hereinafter referred to as MTDATA) so that the weight ratio (wt%) is 1: 1. The doped region 316 can be formed by doping perylene. In addition, it can form by co-evaporating so that the weight ratio (wt%) in the dope region 316 at this time may be (BCP) :( MTDATA) :( perylene) = 50: 50: 5.

  These doped regions 316 are formed with a thickness of 20 to 30 nm.

  A pixel having the organic compound layer that emits red light, the organic compound layer that emits green light, and the organic compound layer 309 that emits blue light as described above is formed in the pixel portion, so that full color display is possible.

  In the organic compound layer 309 shown in this embodiment, the doped region 316 is a light emitting region. However, the doped region 316 is not provided, but a light emitting layer made of a completely different material is interposed between the bipolar layers 315. It can also be formed. In this case, as the material for forming the bipolar layer 315, the above-described materials may be used, and as the material for forming the light emitting layer, 4,4′-bis (2,2-diphenyl-vinyl) -biphenyl is used. (Hereinafter referred to as DPVBi).

On the other hand, when a polymer material is used, PVK and PBD are mixed in toluene at a molar ratio of 1: 0.3, and a dopant tris (2-phenylpyridine) iridium (hereinafter, Ir (ppy) is used. ) ₃ ) is mixed to form a coating liquid by coating so as to have a mole fraction of 3 mol% with respect to the total number of moles of PVK and PBD, and this is formed by coating.

Next, the second auxiliary electrode 310 is formed on the organic compound layer 309. Note that the second auxiliary electrode 310 can also be formed using the same material as the first auxiliary electrode 308, but here, barium fluoride (BaF ₂ ) is formed to a thickness of 1 nm to form the second auxiliary electrode. An electrode 310 is formed. Further, the second auxiliary electrode 310 can be formed only on the first electrode 305 by vapor deposition using a metal mask.

  Finally, a third electrode 311 is formed. Note that as the conductive material for forming the third electrode 311, a material having a work function of 4.5 eV or higher and a high work function is used. Note that the third electrode 311 in this embodiment is a light-transmitting electrode and is formed using a material having a light-transmitting property and a work function of 4.5 eV or more. Specifically, a material such as ITO, IZO, or IDIXO can be used. Here, the third electrode 311 is formed by depositing ITO with a thickness of 100 nm by an evaporation method or a sputtering method.

  As described above, a top emission type light emitting device which has the first light emitting element 312 and the second light emitting element 313 in one pixel and can emit light from the counter electrode side in either light emitting element. Can be formed.

  In this embodiment, the same top emission light emitting device as that shown in Embodiment 2 is described, but the case where the element structure is different will be described.

  4A shows a cross-sectional view of a pixel forming a pixel portion of a light-emitting device. Two types of TFTs (also referred to as current control TFTs) are formed over the substrate 401, and the first electrode 405 is electrically connected to the TFT 1 (402) through the wiring 404, so that the TFT 2 ( 403) is electrically connected to the second electrode (2) 407 through the wiring 406. In this embodiment, the TFT1 (402) is formed by an n-channel TFT, and the TFT2 (403) is formed by a p-channel TFT.

  Note that the connection portion between the wiring 404 and the first electrode 405 and the connection portion between the wiring 406 and the second electrode 407 are covered with an insulating layer 414 made of an insulating material as in the first embodiment. Note that as the material for forming the insulating layer 414, a material similar to that shown in Embodiment 1 may be used. Similarly, an opening is formed at a position corresponding to the first electrode 405 and the second electrode 407 of the insulating film, and the insulating layer 414 is formed.

  On the first electrode 405, an organic compound layer 409, a second auxiliary electrode 410, and a third electrode 411 are stacked, and a first light-emitting element 412 is formed. In addition, over the second electrode 407, a first auxiliary electrode 408, an organic compound layer 409, and a third electrode 411 are stacked, so that a second light-emitting element 413 is formed.

  Note that the first electrode 405, the second electrode 407, and the third electrode 411 are formed of a material having a low work function that can serve as a cathode, and the first auxiliary electrode 408 and the second auxiliary electrode 410 are It is made of a material having a high work function that can be used as an anode. Therefore, in the first light-emitting element 412, the first electrode 405 serves as the first pixel electrode (cathode) 417, and the second auxiliary electrode 410 and the third electrode 411 are stacked. The counter electrode (anode) 418 is formed. In the second light-emitting element 413, a stack of the second electrode 407 and the first auxiliary electrode 408 serves as a second pixel electrode (anode) 419, and the third electrode 411 serves as a second pixel electrode. The counter electrode (cathode) 420 is formed.

  Specific element structures of the first light-emitting element 412 and the second light-emitting element 413 are illustrated in FIG. 4B, and a manufacturing method thereof will be described below.

  However, TFTs and wirings formed on the substrate are not described in this example until they will be described in detail in a later example, and in this example, manufacturing of a light-emitting element formed after the wiring is formed is described. To do.

  First, a first electrode 405 is formed in contact with the wiring 404 and a second electrode 407 is formed in contact with the wiring 406. Note that in this embodiment, in order not to reduce the light emission efficiency of the light-emitting element, it is desirable to have a structure in which light is not emitted from the first electrode 405 and the second electrode 407. Is formed using a material of 3.8 eV or less. Here, a magnesium alloy (Mg: Ag) is formed to a thickness of 100 nm by a sputtering method and then patterned.

  Further, a first auxiliary electrode 408 is formed over the second electrode 407. Note that the material of the first auxiliary electrode 408 in this embodiment is a long-period type periodic table such as gold (Au), platinum (Pt), nickel (Ni), tungsten (W), titanium (Ti), or the like. Elements belonging to Groups 3 to 11 can be used as the conductive material. Here, gold (Au) is formed to a thickness of 20 nm, and the first auxiliary electrode 408 is formed. Further, the first auxiliary electrode 408 can be formed only on the second electrode 407 by vapor deposition using a metal mask.

  Next, an organic compound layer 409 is formed. Note that the film thickness of the organic compound layer 309 in this example is 100 nm.

First, 4,4′-bis [N- (1-naphthyl) -N-phenyl-amino] -biphenyl (hereinafter referred to as α-NPD) having a hole transporting property and an electron transporting property Bipolar layer 415 is formed by co-evaporating tris (8-quinolinolato) aluminum (hereinafter referred to as Alq ₃ ) so that the weight ratio (wt%) is 1: 1.

  Further, in this embodiment, a light emitting layer 416 that becomes a light emitting region is formed during the formation of the bipolar layer 215. In this embodiment, 4,4′-bis (2,2-diphenyl-vinyl) -biphenyl (hereinafter referred to as DPVBi) is used as a material for forming the light-emitting layer 416. The light emitting layer 416 is formed with a thickness of 20 to 30 nm.

  Then, the light emitting region in the organic compound layer 409 can be limited by forming the bipolar layer 415 again over the light emitting layer 416.

  Note that in this embodiment, the case where the light-emitting layer 416 is formed in the organic compound layer is described; however, a doped region as shown in Embodiments 1 and 2 may be provided, or a low molecular weight structure may be provided. It can be formed by using not only a system material but also a polymer material.

Next, the second auxiliary electrode 410 is formed over the organic compound layer 409. Note that the second auxiliary electrode 410 can also be formed using the same material as the first auxiliary electrode 408, but here, barium fluoride (BaF ₂ ) is formed to a thickness of 1 nm to form the second auxiliary electrode. An electrode 410 is formed. In addition, the second auxiliary electrode 410 can be formed only on the first electrode 405 by vapor deposition using a metal mask.

  Finally, a third electrode 411 is formed. Note that as a conductive material for forming the third electrode 411, a material having a work function of 3.8 eV or less and a small work function is used. Note that the third electrode 411 in this embodiment is a light-transmitting electrode and is formed using a material having a work function of 3.8 eV or less. Specifically, in addition to elements belonging to Group 1 or Group 2 of the element periodic rule, that is, alkali metals and alkaline earth metals, and alloys and compounds containing these, transition metals including rare earth metals can be used. Here, the third electrode 411 is formed by stacking cesium (Cs) and silver (Ag) by an evaporation method or a sputtering method and forming a film with a thickness of 20 nm.

  As described above, a top emission type light emitting device which has the first light emitting element 312 and the second light emitting element 313 in one pixel and can emit light from the counter electrode side in either light emitting element. Can be formed.

  An embodiment of the present invention will be described with reference to FIGS. Here, a method for simultaneously manufacturing a pixel portion and TFTs (n-channel TFT and p-channel TFT) of a driver circuit provided around the pixel portion on the same substrate will be described in detail.

  First, a base insulating film 601 is formed over a substrate 600, a first semiconductor film having a crystal structure is obtained, and then a semiconductor layer 602 to 605 separated into island shapes is formed by etching treatment into a desired shape. .

As the substrate 600, a glass substrate (# 1737) is used, and as the base insulating film 601, a silicon oxynitride film formed from a source gas SiH ₄ , NH ₃ , N ₂ O by a plasma CVD method at a film forming temperature of 400 ° C. 601a (composition ratio Si = 32%, O = 27%, N = 24%, H = 17%) is formed to 50 nm (preferably 10 to 200 nm). Next, after cleaning the surface with ozone water, the oxide film on the surface is removed with dilute hydrofluoric acid (1/100 dilution). Next, a silicon oxynitride film 601b (composition ratio Si = 32%, O = 59%, N = 7%, H = 2%) formed from a source gas SiH ₄ and N ₂ O by a plasma CVD method. ) To a thickness of 100 nm (preferably 50 to 200 nm), and further, a semiconductor film having an amorphous structure at a film forming temperature of 300 ° C. and a film forming gas of SiH ₄ by plasma CVD without being exposed to the atmosphere (here) Then, an amorphous silicon film is formed with a thickness of 54 nm (preferably 25 to 80 nm).

Although the base film 601 is shown as a two-layer structure in this embodiment, it may be formed as a single-layer film of the insulating film or a structure in which two or more layers are stacked. The material of the semiconductor film is not limited, but preferably, silicon or silicon germanium (Si _x Ge _1-x (X = 0.0001 to 0.02)) alloy or the like is used, and known means (sputtering method, LPCVD) Or a plasma CVD method or the like). The plasma CVD apparatus may be a single wafer type apparatus or a batch type apparatus. Alternatively, the base insulating film and the semiconductor film may be successively formed without being exposed to the air in the same film formation chamber.

Next, after cleaning the surface of the semiconductor film having an amorphous structure, an extremely thin oxide film of about 2 nm is formed on the surface with ozone water. Next, a small amount of impurity element (boron or phosphorus) is doped in order to control the threshold value of the TFT. Here, an ion doping method in which diborane (B ₂ H ₆ ) is plasma-excited without mass separation is used, the doping condition is an acceleration voltage of 15 kV, diborane is diluted to 1% with hydrogen, the gas flow rate is 30 sccm, and the dose amount is 2 × 10 ^12. Boron was added to the amorphous silicon film at / cm ² .

  Next, a nickel acetate salt solution containing 10 ppm of nickel in terms of weight is applied with a spinner. Instead of coating, a method of spreading nickel element over the entire surface by sputtering may be used.

  Next, heat treatment is performed for crystallization, so that a semiconductor film having a crystal structure is formed. For this heat treatment, heat treatment in an electric furnace or irradiation with strong light may be used. When the heat treatment is performed in an electric furnace, the heat treatment may be performed at 500 to 650 ° C. for 4 to 24 hours. Here, after heat treatment for dehydrogenation (500 ° C., 1 hour), heat treatment for crystallization (550 ° C., 4 hours) is performed to obtain a silicon film having a crystal structure. Although crystallization is performed here using heat treatment using a furnace, crystallization may be performed using a lamp annealing apparatus capable of crystallization in a short time. Although a crystallization technique using nickel as a metal element for promoting crystallization of silicon is used here, other known crystallization techniques such as a solid phase growth method and a laser crystallization method may be used.

Next, after removing the oxide film on the surface of the silicon film having a crystal structure with dilute hydrofluoric acid or the like, irradiation with laser light (XeCl: wavelength 308 nm) for increasing the crystallization rate and repairing defects left in the crystal grains In the air or in an oxygen atmosphere. As the laser light, excimer laser light having a wavelength of 400 nm or less, and second harmonic and third harmonic of YVO ₄ laser are used. In any case, a pulse laser beam having a repetition frequency of about 10 to 1000 Hz is used, and the laser beam is condensed to 100 to 500 mJ / cm ² by an optical system and irradiated with an overlap rate of 90 to 95%. The film surface may be scanned. Here, laser light irradiation is performed in the atmosphere at a repetition frequency of 30 Hz and an energy density of 393 mJ / cm ² . Note that since the reaction is performed in the air or in an oxygen atmosphere, an oxide film is formed on the surface by laser light irradiation.

Alternatively, after removing the oxide film formed by laser light irradiation with dilute hydrofluoric acid, the surface of the semiconductor film may be planarized by performing second laser light irradiation in a nitrogen atmosphere or in a vacuum. In this case, excimer laser light having a wavelength of 400 nm or less, second harmonic and third harmonic of a YAG laser are used as this laser light (second laser light). The energy density of the second laser light is made larger than the energy density of the first laser light, preferably 30 to 60 mJ / cm ² .

  Note that the laser light irradiation here has a gettering effect also in preventing the addition of a rare gas element to the silicon film having a crystal structure when an oxide film is formed and then formed by sputtering. It is very important to increase. Next, in addition to the oxide film formed by laser light irradiation, the surface is treated with ozone water for 120 seconds to form a barrier layer made of an oxide film having a total thickness of 1 to 5 nm.

Next, an amorphous silicon film containing an argon element serving as a gettering site is formed with a thickness of 150 nm on the barrier layer by a sputtering method. The film formation conditions by the sputtering method of this embodiment are as follows: the film formation pressure is 0.3 Pa, the gas (Ar) flow rate is 50 (sccm), the film formation power is 3 kW, and the substrate temperature is 150 ° C. Note that the atomic concentration of the argon element contained in the amorphous silicon film under the above conditions is 3 × 10 ²⁰ / cm ^{3 to} 6 × 10 ²⁰ / cm ³ , and the atomic concentration of oxygen is 1 × 10 ¹⁹ / cm ³ to 3 × 10 ¹⁹ / cm ³ . Thereafter, heat treatment is performed at 650 ° C. for 3 minutes using a lamp annealing apparatus to perform gettering.

  Next, the amorphous silicon film containing an argon element as a gettering site is selectively removed using the barrier layer as an etching stopper, and then the barrier layer is selectively removed with dilute hydrofluoric acid. Note that during gettering, nickel tends to move to a region with a high oxygen concentration, and thus it is desirable to remove the barrier layer made of an oxide film after gettering.

  Next, after forming a thin oxide film with ozone water on the surface of the obtained silicon film having a crystal structure (also called a polysilicon film), a mask made of resist is formed and etched into a desired shape to form islands. A separated semiconductor layer is formed. After the semiconductor layer is formed, the resist mask is removed.

  Further, after forming the semiconductor layer, an impurity element imparting p-type or n-type conductivity may be added in order to control the threshold value (Vth) of the TFT. As impurity elements imparting p-type to a semiconductor, periodic group 13 elements such as boron (B), aluminum (Al), and gallium (Ga) are known. Note that as an impurity element imparting n-type conductivity to a semiconductor, an element belonging to Group 15 of the periodic table, typically phosphorus (P) or arsenic (As) is known.

  Next, after forming a thin oxide film with ozone water on the surface of the obtained silicon film having a crystal structure (also called a polysilicon film), a mask made of resist is formed and etched into a desired shape to form islands. The separated semiconductor layers 602 to 605 are formed. After the semiconductor layer is formed, the resist mask is removed.

  Next, the oxide film is removed with an etchant containing hydrofluoric acid, and at the same time, the surface of the silicon film is washed, and then an insulating film containing silicon as a main component to be the gate insulating film 607 is formed. In this embodiment, a silicon oxynitride film (composition ratio: Si = 32%, O = 59%, N = 7%, H = 2%) is formed to a thickness of 115 nm by plasma CVD.

  Next, as illustrated in FIG. 5A, a first conductive film 608 with a thickness of 20 to 100 nm and a second conductive film 609 with a thickness of 100 to 400 nm are stacked over the gate insulating film 607. In this embodiment, a tantalum nitride film having a thickness of 50 nm and a tungsten film having a thickness of 370 nm are sequentially stacked over the gate insulating film 607.

  The conductive material for forming the first conductive film and the second conductive film is an element selected from Ta, W, Ti, Mo, Al, and Cu, or an alloy material or a compound material containing the element as a main component. Form. Alternatively, a semiconductor film typified by a polycrystalline silicon film doped with an impurity element such as phosphorus, or an Ag: Pd: Cu alloy may be used as the first conductive film and the second conductive film. Further, the present invention is not limited to the two-layer structure. For example, a three-layer structure in which a 50 nm-thickness tungsten film, a 500 nm-thick aluminum and silicon alloy (Al-Si) film, and a 30 nm-thickness titanium nitride film are sequentially stacked Also good. In the case of a three-layer structure, tungsten nitride may be used instead of tungsten of the first conductive film, or aluminum instead of the aluminum and silicon alloy (Al-Si) film of the second conductive film. A titanium alloy film (Al—Ti) may be used, or a titanium film may be used instead of the titanium nitride film of the third conductive film. Moreover, a single layer structure may be sufficient.

Next, as shown in FIG. 5B, resist masks 610 to 613 are formed by a light exposure process, and a first etching process for forming gate electrodes and wirings is performed. The first etching process is performed under the first and second etching conditions. For etching, an ICP (Inductively Coupled Plasma) etching method may be used. Using the ICP etching method, the film is formed into a desired taper shape by appropriately adjusting the etching conditions (the amount of power applied to the coil-type electrode, the amount of power applied to the substrate-side electrode, the electrode temperature on the substrate side, etc.) Can be etched. As an etching _{gas, Cl 2, BCl 3, SiCl} 4, CCl 4 chlorine gas or CF ₄ to the typified like, SF _6, fluorine-based gas NF ₃ and the like typified, or O ₂ as appropriate Can be used.

In this embodiment, 150 W RF (13.56 MHz) power is also applied to the substrate side (sample stage), and a substantially negative self-bias voltage is applied. The electrode area size on the substrate side is 12.5 cm × 12.5 cm, and the coil-type electrode area size (here, the quartz disk provided with the coil) is a disk having a diameter of 25 cm. The W film is etched under this first etching condition so that the end portion of the first conductive layer is tapered. Under the first etching conditions, the etching rate with respect to W is 200.39 nm / min, the etching rate with respect to TaN is 80.32 nm / min, and the selection ratio of W with respect to TaN is about 2.5. Further, the taper angle of W is about 26 ° under this first etching condition. Thereafter, the resist masks 610 to 613 are not removed and the second etching conditions are changed, CF ₄ and Cl ₂ are used as etching gases, and the respective gas flow ratios are set to 30/30 (sccm). Etching was performed for about 30 seconds by applying 500 W of RF (13.56 MHz) power to the coil-type electrode at a pressure of 1 Pa to generate plasma. 20 W RF (13.56 MHz) power is also applied to the substrate side (sample stage), and a substantially negative self-bias voltage is applied. Under the second etching condition in which CF ₄ and Cl ₂ are mixed, the W film and the TaN film are etched to the same extent. The etching rate for W under the second etching conditions is 58.97 nm / min, and the etching rate for TaN is 66.43 nm / min. Note that in order to perform etching without leaving a residue on the gate insulating film, it is preferable to increase the etching time at a rate of about 10 to 20%.

  In the first etching process, the shape of the mask made of resist is made suitable, and the end portions of the first conductive layer and the second conductive layer are tapered due to the effect of the bias voltage applied to the substrate side. It becomes. The angle of the tapered portion may be 15 to 45 °.

  Thus, the first shape conductive layers 615 to 618 (the first conductive layers 615 a to 618 a and the second conductive layers 615 b to 618 b) composed of the first conductive layer and the second conductive layer by the first etching treatment. Form. The insulating film 607 to be a gate insulating film is etched by about 10 to 20 nm to be a gate insulating film 620 in which a region not covered with the first shape conductive layers 615 to 618 is thinned.

Next, a second etching process is performed without removing the resist mask. Here, SF ₆ , Cl _2, and O ₂ are used as etching gases, the gas flow ratios are 24/12/24 (sccm), and 700 W of RF ( (13.56 MHz) Electric power was applied to generate plasma, and etching was performed for 25 seconds. 10 W RF (13.56 MHz) power is also applied to the substrate side (sample stage), and a substantially negative self-bias voltage is applied. In the second etching process, the etching rate with respect to W is 227.3 nm / min, the etching rate with respect to TaN is 32.1 nm / min, the selection ratio of W with respect to TaN is 7.1, and the SiON that is the insulating film 620 The etching rate with respect to is 33.7 nm / min, and the selective ratio of W to SiON is 6.83. As described above, when SF ₆ is used as the etching gas, the selectivity with respect to the insulating film 620 is high, so that film loss can be suppressed. In this embodiment, the insulating film 620 is reduced only by about 8 nm.

  By this second etching process, the taper angle of W became 70 °. Second conductive layers 621b to 624b are formed by the second etching process. On the other hand, the first conductive layer is hardly etched and becomes the first conductive layers 621a to 624a. Note that the first conductive layers 621a to 624a are approximately the same size as the first conductive layers 615a to 618a. Actually, the width of the first conductive layer may be about 0.3 μm, that is, the entire line width may be receded by about 0.6 μm as compared with that before the second etching process, but the size is hardly changed.

In place of the two-layer structure, a three-layer structure in which a 50-nm-thick tungsten film, a 500-nm-thick aluminum and silicon alloy (Al-Si) film, and a 30-nm-thick titanium nitride film are sequentially stacked, As the first etching condition in the first etching process, BCl ₃ , Cl _2, and O ₂ are used as source gases, the respective gas flow ratios are set to 65/10/5 (sccm), and the substrate side (sample stage). ) 300W RF (13.56MHz) power is applied to the coil-type electrode at a pressure of 1.2Pa and 450W RF (13.56MHz) power is generated to generate plasma and perform etching for 117 seconds. Ebayoku, as the second etching conditions of the first etching treatment, CF ₄ and using a Cl ₂ and O _2, a ratio of respective gas flow rates is 25/25/10 (scc ) And 20 W of RF (13.56 MHz) power is also applied to the substrate side (sample stage), and 500 W of RF (13.56 MHz) power is applied to the coil-type electrode at a pressure of 1 Pa to generate plasma. The second etching process uses BCl ₃ and Cl ₂ , the gas flow ratio is 20/60 (sccm), and the substrate side (sample stage) is 100 W. RF (13.56 MHz) power is applied, 600 W RF (13.56 MHz) power is applied to the coil-type electrode at a pressure of 1.2 Pa, plasma is generated, and etching is performed.

Next, after removing the resist mask, a first doping process is performed to obtain the state of FIG. The doping process may be performed by ion doping or ion implantation. The conditions of the ion doping method are a dose amount of 1.5 × 10 ¹⁴ atoms / cm ² and an acceleration voltage of 60 to 100 keV. Typically, phosphorus (P) or arsenic (As) is used as the impurity element imparting n-type conductivity. In this case, the first conductive layer and the second conductive layers 621 to 624 serve as a mask for the impurity element imparting n-type, and the first impurity regions 626 to 629 are formed in a self-aligning manner. An impurity element imparting n-type conductivity is added to the first impurity regions 626 to 629 in a concentration range of 1 × 10 ¹⁶ to 1 × 10 ¹⁷ / cm ³ . Here, a region having the same concentration range as the first impurity region is also referred to as an n ⁻ region.

  In this embodiment, the first doping process is performed after removing the resist mask, but the first doping process may be performed without removing the resist mask.

  Next, as shown in FIG. 6B, resist masks 631 to 633 are formed, and a second doping process is performed. The mask 631 is a mask for protecting the channel formation region of the semiconductor layer forming the p-channel TFT of the driver circuit and its peripheral region, and the mask 632 is the channel formation region of the semiconductor layer forming the TFT of the pixel portion and its periphery. This mask protects the area.

The condition of the ion doping method in the second doping process is that the dose is 1.5 × 10 ¹⁵ atoms / cm ² , the acceleration voltage is 60 to 100 keV, and phosphorus (P) is doped. Here, impurity regions are formed in a self-aligned manner in each semiconductor layer using the second conductive layer 621b as a mask. Of course, it is not added to the region covered with the masks 631 to 633. Thus, second impurity regions 634 and 635 and a third impurity region 637 are formed. An impurity element imparting n-type conductivity is added to the second impurity regions 634 and 635 in a concentration range of 1 × 10 ²⁰ to 1 × 10 ²¹ / cm ³ . Here, a region having the same concentration range as the second impurity region is also referred to as an n ⁺ region.

The third impurity region is formed by the first conductive layer at a lower concentration than the second impurity region and imparts n-type in a concentration range of 1 × 10 ¹⁸ to 1 × 10 ¹⁹ / cm ^3. Will be added. Note that the third impurity region has a concentration gradient in which the impurity concentration increases toward the end portion of the tapered portion because doping is performed by passing the portion of the first conductive layer having a tapered shape. . Here, a region having the same concentration range as the third impurity region is also referred to as an n ⁻ region. Further, the region covered with the mask 632 becomes the first impurity region 638 without being doped with the impurity element in the second doping treatment.

  Next, after removing the resist masks 631 to 633, new resist masks 639 and 640 are formed, and a third doping process is performed as shown in FIG. 6C.

In the driver circuit, a fourth impurity region 641 in which an impurity element imparting p-type conductivity is added to the semiconductor layer forming the p-channel TFT and the semiconductor layer forming the storage capacitor by the third doping treatment. 642 and fifth impurity regions 643, 644 are formed.

In addition, an impurity element imparting p-type conductivity is added to the fourth impurity regions 641 and 642 in a concentration range of 1 × 10 ²⁰ to 1 × 10 ²¹ / cm ³ . Note that the fourth impurity regions 641 and 642 are regions to which phosphorus (P) is added in the previous step (n ⁻ region), but the concentration of the impurity element imparting p-type is 1.5 to Three times as much is added and the conductivity type is p-type. Here, a region having the same concentration range as the fourth impurity region is also referred to as a p ⁺ region.

The fifth impurity regions 643 and 644 are formed in a region overlapping with the tapered portion of the second conductive layer 125a, and have a p-type in a concentration range of 1 × 10 ¹⁸ to 1 × 10 ²⁰ / cm ^3. An impurity element to be added is added. Here, a region having the same concentration range as the fifth impurity region is also referred to as a p ⁻ region.

  Through the above steps, impurity regions having n-type or p-type conductivity are formed in each semiconductor layer. The conductive layers 621 to 624 serve as TFT gate electrodes.

  Next, an insulating film (not shown) that covers substantially the entire surface is formed. In this example, a 50 nm-thickness silicon oxide film was formed by plasma CVD. Of course, this insulating film is not limited to the silicon oxide film, and another insulating film containing silicon may be used as a single layer or a laminated structure.

  Next, a step of activating the impurity element added to each semiconductor layer is performed. This activation step may be a rapid thermal annealing method (RTA method) using a lamp light source, a method of irradiating a YAG laser or an excimer laser from the back surface, a heat treatment using a furnace, or a combination thereof. By different methods.

  Further, in this embodiment, an example in which an insulating film is formed before the activation is shown, but an insulating film may be formed after the activation.

  Next, a first interlayer insulating film 645 made of a silicon nitride film is formed and subjected to heat treatment (heat treatment at 300 to 550 ° C. for 1 to 12 hours) to hydrogenate the semiconductor layer (FIG. 7A). ). This step is a step of terminating dangling bonds in the semiconductor layer with hydrogen contained in the first interlayer insulating film 645. The semiconductor layer can be hydrogenated regardless of the presence of an insulating film (not shown) made of a silicon oxide film. However, in this embodiment, since the material containing aluminum as a main component is used for the second conductive layer, it is important to set the heat treatment conditions that the second conductive layer can withstand in the hydrogenation step. As another means of hydrogenation, plasma hydrogenation (using hydrogen excited by plasma) may be performed.

  Next, a second interlayer insulating film 646 made of an organic insulating material is formed on the first interlayer insulating film 645. In this embodiment, an acrylic resin film having a thickness of 1.6 μm is formed. Next, contact holes reaching the respective impurity regions are formed. In this embodiment, a plurality of etching processes are sequentially performed. In this embodiment, after etching the second interlayer insulating film using the first interlayer insulating film as an etching stopper, the first interlayer insulating film is etched using the insulating film (not shown) as an etching stopper, and then the insulating film (illustrated). Not etched).

Thereafter, wiring is formed using Al, Ti, Mo, W, or the like. In some cases, the pixel electrode of the light-emitting element formed in contact with the wiring can be formed at the same time. As materials for these electrodes and pixel electrodes, it is desirable to use a material having excellent reflectivity such as a film mainly composed of Al or Ag, or a laminated film thereof. In this way, wirings 650 to 657 are formed.

  As described above, the pixel circuit 706 having the n-channel TFT 701 and the p-channel TFT 702, the switching TFT 703 made of the n-channel TFT, and the current control TFT 704 made of the p-channel TFT is the same. It can be formed over a substrate (FIG. 7C). In this specification, such a substrate is referred to as an active matrix substrate for convenience.

In the pixel portion 706, the switching TFT 703 (n-channel TFT) includes a channel formation region 503, a first impurity region (n ⁻ region) 638 formed outside the conductive layer 623 forming the gate electrode, and a source region. Or a second impurity region (n ⁺ region) 635 functioning as a drain region.

In the pixel portion 706, the current control TFT 704 (p-channel TFT) includes a channel formation region 504 and a fourth impurity region (n ⁻ region) 644 formed outside the conductive layer 624 forming the gate electrode. And a fifth impurity region (n ⁺ region) 642 which functions as a source region or a drain region. Note that in the present invention, the light-emitting element is connected to the electrode through the wiring 656 electrically connected to the fifth impurity region (n ⁺ region) 642. In the case of this embodiment, since the current control TFT 704 is formed of a p-channel TFT, it is preferable to form the anode of the light emitting element.

In the driver circuit 705, the n-channel TFT 701 includes a channel formation region 501, a third impurity region (n ⁻ region) 637 that overlaps with a part of the conductive layer 621 forming the gate electrode through an insulating film, a source region, Alternatively, a second impurity region (n ⁺ region) 634 which functions as a drain region is provided.

In the driver circuit 705, the p-channel TFT 702 includes a channel formation region 502, a fifth impurity region (p ⁻ region) 643 overlapping with part of the conductive layer 622 forming the gate electrode through an insulating film, a source region Alternatively, a fourth impurity region (p ⁺ region) 641 functioning as a drain region is provided.

  A driving circuit 705 may be formed by appropriately combining these TFTs 701 and 702 to form a shift register circuit, a buffer circuit, a level shifter circuit, a latch circuit, and the like. For example, in the case of forming a CMOS circuit, an n-channel TFT 701 and a p-channel TFT 702 may be complementarily connected.

  The circuit in which reliability is given top priority is a so-called GOLD (Gate-drain Overlapped LDD) structure in which an LDD (LDD: Lightly Doped Drain) region is overlapped with a gate electrode through a gate insulating film. A certain n-channel TFT 701 structure is suitable.

  Note that TFTs (n-channel TFTs and p-channel TFTs) in the driver circuit 705 are required to have high driving ability (on current: Ion) and to prevent deterioration due to the hot carrier effect and to improve reliability. In this embodiment, a TFT having a region (GOLD region) in which a gate electrode overlaps with a low concentration impurity region through a gate insulating film is used as a structure effective for preventing deterioration of an on-current value due to hot carriers. .

  On the other hand, since the switching TFT 703 in the pixel portion 706 requires a low off-current (Ioff), in this embodiment, the gate electrode has a gate insulating film as a TFT structure for reducing the off-current. A TFT having a region (LDD region) that does not overlap with the low-concentration impurity region is used.

  Note that in the manufacturing process of the light-emitting device in this embodiment, the source signal line is formed using the material forming the gate electrode and the source and drain electrodes are formed because of the circuit configuration and the process. Although the gate signal line is formed using the wiring material, it is possible to use different materials.

  In this embodiment, the driving voltage of the TFT is 1.2 to 10V, preferably 2.5 to 5.5V.

  Further, when the display of the pixel portion is in operation (in the case of moving image display), the background is displayed by the pixel emitting light, and the character display is performed by the pixel where the light emitting element does not emit light. However, when the video display of the pixel portion is stationary for a certain period or longer (referred to as standby in this specification), the display method is switched (reversed) to save power. It is good to leave. Specifically, a character is displayed by a pixel from which the light emitting element emits light (also referred to as character display), and a background is displayed by a pixel from which the light emitting element does not emit light (also referred to as background display).

  Next, the case where the light-emitting device of the present invention is driven by a constant voltage method will be described with reference to FIGS.

  FIG. 8A shows a block diagram of a light emitting device in this embodiment. Reference numeral 801 denotes a source signal line driver circuit, 802 denotes a gate signal line driver circuit, and 803 denotes a pixel portion. In this embodiment, one source signal line driving circuit and one gate signal line driving circuit are provided, but the present invention is not limited to this configuration. Two source signal line driver circuits may be provided, or two gate signal line driver circuits may be provided.

  The source signal line driver circuit 801 includes a shift register 801a, a level shifter 801b, and a sampling circuit 801c. Note that the level shifter 801b may be used as necessary, and is not necessarily used. In this embodiment, the level shifter 801b is provided between the shift register 801a and the sampling circuit 801c. However, the present invention is not limited to this configuration. A configuration in which a level shifter 801b is incorporated in the shift register 801a may be employed.

  The gate signal line driver circuit 802 includes a shift register and a buffer (both not shown). Moreover, you may have a level shifter. Note that a gate signal line 805 is connected to the gate signal line driver circuit 802.

  A clock signal (CLK) and a start pulse signal (SP) which are panel control signals are input to the shift register 801a. A sampling signal for sampling the video signal is output from the shift register 801a. The output sampling signal is input to the level shifter 801b, and the amplitude of the potential is increased and output.

  The sampling signal output from the level shifter 801b is input to the sampling circuit 801c. At the same time, a video signal is input to the sampling circuit 801c via the video signal line.

  In the sampling circuit 801c, the input video signal is sampled by the sampling signal and input to the source signal line 804, respectively.

  Next, FIG. 9A illustrates a pixel structure of the pixel portion 803 of the light-emitting device illustrated in FIG. Note that the pixel portion 803 includes a plurality of pixels having a structure denoted by 900 in FIG. 9A. The pixel 900 includes a source signal line (S), a current supply line (V), and a gate signal line (G ).

  The pixel 900 includes a switching TFT 901, a current control TFT (1) 902, a current control TFT (2) 903, a light emitting element (1) 904, and a light emitting element (2) 905. Yes.

  The gate electrode of the switching TFT 901 is connected to the gate signal line (G). One of the source region and the drain region of the switching TFT 901 is connected to the source signal line (S), and the other is connected to the gate electrodes of the current control TFT (1) 902 and the current control TFT (2) 903. .

  The source regions of the current control TFT (1) 902 and the current control TFT (2) 903 are connected to the current supply line (V), and the drain region of the current control TFT (1) 902 is the light emitting element (1). It is connected to either the anode or the cathode of 904. In addition, the drain region of the current control TFT (2) 903 is connected to a different type of electrode (either the anode or the cathode) from that connected to the drain region of the current control TFT (1) 902. The This electrode is one of the electrodes forming the light emitting element (2) 905.

  In the present specification, the electrode connected to the drain region of the current control TFT (1) 902 is referred to as the pixel electrode (1) and the electrode connected to the drain region of the current control TFT (2) 903. The electrode is called a pixel electrode (2). That is, the light emitting element (1) 904 included in the pixel 900 includes the pixel electrode (1), and the light emitting element (2) 905 includes the pixel electrode (2). In addition, a voltage is input from the current supply line (V) to the pixel electrode (1) and the pixel electrode (2). The voltage input from the current supply line (V) is called a power supply voltage.

  The light emitting element (1) 904 and the light emitting element (2) 905 are formed by these pixel electrodes and the other electrode. The other electrode is called a counter electrode. That is, the light emitting element (1) 904 has a counter electrode (1), and the light emitting element (2) 905 has a counter electrode (2).

  Note that the counter electrode (1) and the counter electrode (2) are each maintained at a predetermined voltage. In this specification, the voltage input from the counter electrode (1) and the counter electrode (2) is referred to as the counter voltage. Call. A power source that applies a counter voltage to the counter electrode (1) is referred to as a counter power source (1) 906, and a power source that applies a counter voltage to the counter electrode (2) is referred to as a counter power source (2) 907.

  A voltage difference between the counter voltage of the counter electrode and the power supply voltage of the pixel electrode is a light emitting element driving voltage, and this light emitting element driving voltage is applied to the organic compound layer.

  Although not shown here, a capacitor may be formed between the gate electrode of the current control TFT (1) 902 and the current control TFT (2) 903 and the current supply line (V).

  FIG. 9B illustrates a circuit configuration for controlling signals input from the counter power source (1) 906 and the counter power source (2) 907 of the pixel 900 illustrated in FIG. 9A. That is, when the switching signal 909 is input to the circuit 908, the switching switch 910 is switched, and either the counter power source (1) 906 or the counter power source (2) 907 is selected, and a voltage is input from the selected counter power source. It has come to be.

  Next, FIG. 9C illustrates voltages input from the counter power source (1) 906 and the counter power source (2) 907, respectively. That is, two types of counter voltages having different polarities of the light emitting element driving voltages are alternately input from the counter power source (1) 906 and the counter power source (2) 907. (1) The voltage input simultaneously from 906 and the counter power supply (2) 907 is different.

  In this embodiment, when the switching TFT 901 of the pixel 900 is turned on, both the current control TFT (1) 902 and the current control TFT (2) 903 are turned on. Note that a constant power supply voltage is input from the current supply line (V), and a constant voltage is applied to the pixel electrode (1) and the pixel electrode (2) of the light emitting element (1) 904 and the light emitting element (2) 905. The

  Here, if the pixel electrode (1) is formed of an anode and the pixel electrode (2) is formed of a cathode, the counter voltage input from the counter power source (1) 906 to the counter electrode (1) is When the voltage is lower than the voltage, a positive light emitting element driving voltage is applied to the light emitting element (1) 904, so that a desired current flows through the light emitting element (1) 904, but the counter voltage input to the counter electrode (1). However, when the voltage is higher than the power supply voltage, a negative light-emitting element driving voltage is applied to the light-emitting element (1) 904, so that no current flows through the light-emitting element (1) 904. Note that in this specification, such a state in which current flows through the light-emitting element is referred to as a function of the light-emitting element.

  On the other hand, when the counter voltage input from the counter power source (2) 907 to the counter electrode (2) is higher than the power source voltage, a positive light emitting element driving voltage is applied to the light emitting element (2) 905. Therefore, a desired current flows through the light emitting element (2) 905 and the light emitting element (2) functions. However, when the counter voltage input to the counter electrode (2) is lower than the power supply voltage, the light emitting element (1). Since a negative light emitting element driving voltage is applied to 904, no current flows through the light emitting element (1) 904, and the light emitting element (2) does not function.

  As described above, two types of counter voltages having opposite polarities of the light emitting element driving voltages are alternately input from the two types of counter power sources respectively included in the two types of light emitting elements formed in one pixel. In addition, by allowing a voltage to be input only from one of the opposing power supplies, one of the two types of light emitting elements can always function.

  Next, the case where the light emitting device of the present invention is driven by a method different from that shown in Embodiment 5 will be described with reference to FIGS.

  FIG. 10 is a block diagram of the light emitting device in this embodiment. Reference numeral 1001 denotes a source signal line driver circuit (A), reference numeral 1002 denotes a source signal line driver circuit (B), reference numeral 1003 denotes a gate signal line driver circuit, and reference numeral 1004 denotes a pixel portion.

  The source signal line driver circuit (A) 1001 includes a shift register 1001a, a level shifter 1001b, and a sampling circuit 1001c. Note that the level shifter 1001b may be used as necessary, and is not necessarily used. In this embodiment, the level shifter 1001b is provided between the shift register 1001a and the sampling circuit 1001c. However, the present invention is not limited to this configuration. A structure in which a level shifter 1001b is incorporated in the shift register 1001a may be employed. Note that although the source signal line driver circuit (B) 1002 is provided in this embodiment, these structures can be the same as those of the source signal line driver circuit (A) 1001.

  The gate signal line driver circuit 1003 includes a shift register and a buffer (both not shown). Moreover, you may have a level shifter. Note that a gate signal line 1005 is connected to the gate signal line driver circuit 1003.

  A clock signal (CLK) and a start pulse signal (SP) which are panel control signals are input to the shift register 1001a. A sampling signal for sampling the video signal is output from the shift register 1001a. The output sampling signal is input to the level shifter 1001b, and the potential amplitude is increased and output.

  The sampling signal output from the level shifter 1001b is input to the sampling circuit 1001c. At the same time, a video signal is input to the sampling circuit 1001c via the video signal line.

  In the sampling circuit 1001c, the input video signal is sampled by the sampling signal and input to the source signal line (1) 1006, respectively. Note that the source signal line driver circuit (B) 1002 inputs the signal to the source signal line (2) 1007 in the same manner.

  Next, FIG. 11 illustrates a pixel structure of the pixel portion 1004 of the light-emitting device illustrated in FIG. Note that the pixel portion 1004 includes a plurality of pixels having a structure indicated by 1100 in FIG. 11. The pixel 1100 includes two types of source signal lines (S), that is, source signal lines (1) and (S) and source signal lines. (2) (S ′) Two types of current supply lines (V), that is, current supply lines (1) and (V), current supply lines (2) and (V ′), and gate signal lines (G) are provided. is doing.

  The pixel 1100 includes two types of switching TFTs, ie, switching TFTs (1) (1101), switching TFTs (2) (1102), and two types of current control TFTs, ie, current control TFTs (1). (1103), a current control TFT (2) 1104, two kinds of light emitting elements, that is, a light emitting element (1) 1105, and a light emitting element (2) 1106.

  The gate electrodes of the switching TFT (1) 1101 and the switching TFT (2) 1102 are connected to the gate signal line (G). One of the source region and the drain region of the switching TFT (1) 1101 is connected to the source signal line (1) (S), and the other is connected to the gate electrode of the current control TFT (1) 1103. Further, one of the source region and the drain region of the switching TFT (2) 1102 is connected to the source signal line (2) (S ′), and the other is connected to the gate electrode of the current control TFT (2) 1104. .

  The source region of the current control TFT (1) 1103 is connected to the current supply line (1) (V), and the drain region of the current control TFT (1) 1103 is the anode of the light emitting element (1) 1105, or Connected to the electrode to be the cathode. Note that this electrode is one of the electrodes forming the light emitting element (1) 1105. The source region of the current control TFT (2) 1104 is connected to the current supply line (2) (V ′), and the drain region of the current control TFT (2) 1104 is the current control TFT (1). 1103 is connected to an electrode of a different type (anode or cathode) from that connected to the drain region 1103. This electrode is one of the electrodes forming the light emitting element (2) 1106.

  In the present specification, the electrode connected to the drain region of the current control TFT (1) 1103 is referred to as a pixel electrode (1) and the electrode connected to the drain region of the current control TFT (2) 1104. The electrode is called a pixel electrode (2). That is, the light-emitting element (1) 1105 included in the pixel 1100 includes the pixel electrode (1), and the light-emitting element (2) 1106 includes the pixel electrode (2). In addition, a voltage is input to the pixel electrode (1) from the current supply line (1) (V), and a voltage is input to the pixel electrode (2) from the current supply line (2) (V ′). The voltages input from the current supply line (1) (V) and the current supply line (2) (V ') are referred to as a power supply voltage (1) and a power supply voltage (2), respectively.

  The light-emitting element (1) 1105 and the light-emitting element (2) 1106 are formed using these pixel electrodes and the other electrode. The other electrode is called a counter electrode. That is, the light emitting element (1) 1105 has a counter electrode (1), and the light emitting element (2) 1106 has a counter electrode (2).

  Note that the counter electrode (1) and the counter electrode (2) are each maintained at a predetermined voltage. In this specification, the voltage input from the counter electrode (1) and the counter electrode (2) is referred to as the counter voltage. Call. A power source that applies a counter voltage to the counter electrode (1) is referred to as a counter power source (1) 1107, and a power source that applies a counter voltage to the counter electrode (2) is referred to as a counter power source (2) 1108. In this embodiment, the counter power supply (1) 1107 and the counter electrode (2) 1108 are held at a constant voltage.

  The anode voltage is preferably higher than the voltage applied to the cathode. Therefore, the counter voltage varies depending on whether the counter electrode is an anode or a cathode. For example, when the counter electrode is an anode, the counter voltage is preferably higher than the power supply voltage. Conversely, when the counter electrode is a cathode, the counter voltage is preferably lower than the power supply voltage.

  A voltage difference between the counter voltage of the counter electrode and the power supply voltage of the pixel electrode is a light emitting element driving voltage, and this light emitting element driving voltage is applied to the organic compound layer.

  Furthermore, FIG. 12 shows a timing chart in the case of driving the light emitting device described in FIG. A period from when one gate signal line is selected to when another gate signal line is selected next is referred to as one line period (L). Note that selection of a gate signal line in this specification means that a selection signal having a potential such that the switching TFT is turned on is input to the gate signal line.

  A period from when one image is displayed until the next image is displayed corresponds to one frame period (F). For example, a light emitting device having y gate signal lines is provided with y line periods (L1 to Ly) in one frame period.

  In the first line period (L1), the gate signal lines (G (1) to G (y)) are selected by the selection signal input from the gate signal line driver circuit 1003 and connected to the gate signal line (G). All the switching TFTs are turned on. Then, x source signal lines (1) (S (1) to S (x)) from the source signal line driver circuit (A) 1001 and x source signal lines from the source signal line driver circuit (B) 1002 are provided. (2) Video signals are sequentially input to (S ′ (1) to S ′ (x)). Here, the gate signal line (G (1)), the source signal line (1) (S (1)), and the source signal line (2) (S ′ (1)) are shown. Note that the video signal input to the source signal line (1) (S (1) to S (x)) is input to the gate electrode of the current control TFT (1) 1103 via the switching TFT (1) 1101. The video signal input to the source signal line (2) (S ′ (1) to S ′ (x)) is supplied to the gate electrode of the current control TFT (2) 1104 via the switching TFT (2) 1102. Is input.

  In addition, the power supply voltage (1) is input from the x current supply lines (1) (V (1) to V (x)) to the pixel electrode (1) included in each pixel, and is supplied to the pixel electrode (2). The power supply voltage (2) is input from the x current supply lines (2) (V ′ (1) to V ′ (x)). Here, the current supply line (1) (V (1)) and the current supply line (2) (V '(1)) are shown.

The amount of current flowing through the channel formation region of the current control TFT (1) 1103 and the current control TFT (2) 1104 is controlled by a gate voltage V _gs which is a voltage difference between the gate electrode and the source region. Therefore, the voltage applied to each pixel electrode of the light emitting element (1) 1105 and the light emitting element (2) 1106 is determined by the voltage level of the video signal input to the gate electrode of each current control TFT. Therefore, the light-emitting element (1) 1105 and the light-emitting element (2) 1106 emit light by being controlled by the voltage of the video signal.

  The operation described above is repeated, and video signals are input to the source signal line (1) (S (1) to S (x)) and the source signal line (2) (S ′ (1) to S ′ (x)). When is finished, the first line period (L1) is finished. Then, the second line period (L2) is started, the gate signal line (G2) is selected by the selection signal, and similarly to the first line period (L1), the source signal line (1) (S (1)) is selected. To S (x)) and the source signal line (2) (S ′ (1) to S ′ (x)) are sequentially input.

  When all the gate signal lines (G1 to Gy) are selected, all the line periods (L1 to Ly) are finished. When all the line periods (L1 to Ly) end, one frame period ends. All pixels display during one frame period, and one image is formed. In this embodiment, the power supply voltage (1) input from the current supply line (1) and the power supply voltage (2) input from the current supply line (2) are alternately switched every frame. Accordingly, the light emitting element (1) 1105 and the light emitting element (2) 1106 function alternately.

  As described above, the light emission amounts of the light emitting element (1) 1105 and the light emitting element (2) 1106 are controlled by the voltage of the video signal, and gradation display is performed by controlling the light emission amount.

  In this embodiment, an external view of an active matrix light-emitting device of the present invention will be described with reference to FIG. 13A is a top view illustrating the light-emitting device, and FIG. 13B is a cross-sectional view taken along line A-A ′ in FIG. 13A. Reference numeral 1301 indicated by a dotted line denotes a source signal line driver circuit, 1302 denotes a pixel portion, and 1303 denotes a gate signal line driver circuit. Reference numeral 1304 denotes a sealing substrate, 1305 denotes a sealant, and the inside surrounded by the sealant 1305 is a space 1307.

  Reference numeral 1308 denotes a wiring for transmitting signals input to the source signal line driver circuit 1301 and the gate signal line driver circuit 1303. A video signal and a clock signal are received from an FPC (flexible printed circuit) 1309 as an external input terminal. receive. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to the FPC. The light-emitting device in this specification includes not only a light-emitting device body but also a state in which an FPC or a PWB is attached thereto.

  Next, a cross-sectional structure will be described with reference to FIG. A driver circuit and a pixel portion are formed over the substrate 1310. Here, a source signal line driver circuit 1301 and a pixel portion 1302 are shown as the driver circuits.

  Note that as the source signal line driver circuit 1301, a CMOS circuit in which an n-channel TFT 1313 and a p-channel TFT 1314 are combined is formed. The TFT forming the driving circuit may be formed by a known CMOS circuit, PMOS circuit or NMOS circuit. Further, in this embodiment, a driver integrated type in which a drive circuit is formed on a substrate is shown, but this is not always necessary, and it can be formed outside the substrate.

  The pixel portion 1302 is formed by a plurality of pixels including a current control TFT 1311 and an anode 1312 electrically connected to the drain thereof.

  An insulating layer 1313 is formed on both ends of the anode 1312, and an organic compound layer 1314 is formed on the anode 1312. Further, a cathode 1316 is formed on the organic compound layer 1314. Thus, a light-emitting element 1318 including the anode 1312, the organic compound layer 1314, and the cathode 1316 is formed.

  The cathode 1316 also functions as a wiring common to all pixels, and is electrically connected to the FPC 1309 via the connection wiring 1308.

  In addition, a sealing substrate 1304 is attached to the light emitting element 1318 formed over the substrate 1310 with a sealant 1305. Note that a spacer made of a resin film may be provided in order to secure a gap between the sealing substrate 1304 and the light-emitting element 1318. A space 1307 inside the sealing agent 1305 is filled with an inert gas such as nitrogen. Note that an epoxy resin is preferably used as the sealant 1305. In addition, the sealing agent 1305 is desirably a material that does not transmit moisture and oxygen as much as possible. Further, a substance having an effect of absorbing oxygen or water may be contained in the space 1307.

  In this embodiment, a plastic substrate made of FRP (Fiberglass-Reinforced Plastics), PVF (polyvinyl fluoride), Mylar, polyester, acrylic, or the like is used as a material constituting the sealing substrate 1304 in addition to a glass substrate or a quartz substrate. be able to. Further, after the sealing substrate 1304 is bonded using the sealing agent 1305, the sealing substrate 1304 can be further sealed with a sealing agent so as to cover the side surface (exposed surface).

  By enclosing the light emitting element in the space 1307 as described above, the light emitting element can be completely blocked from the outside, and a substance that promotes deterioration of the organic compound layer such as moisture and oxygen can be prevented from entering from the outside. Can do. Therefore, a highly reliable light-emitting device can be obtained.

  In addition, the structure of a present Example can be implemented in combination freely with any structure shown in Examples 1-6.

  In this embodiment, a case where a passive (simple matrix) light-emitting device having the element structure of the present invention is manufactured will be described. FIG. 14 is used for the description. In FIG. 14, 1401 is a glass substrate, and 1402 is a first electrode made of an anode material. In this embodiment, ITO is formed as the first electrode 1402 by a sputtering method. Although not shown in FIG. 14, a plurality of first electrodes are arranged in stripes parallel to the paper surface.

  A bank 1403 made of an insulating material is formed so as to cross the first electrodes 1402 arranged in a stripe shape. The bank 1403 is in contact with the anode 1402 and formed in a direction perpendicular to the paper surface.

  Here, a first auxiliary electrode 1404 is formed on a part of the first electrode 1402 on the surface by an evaporation method. Note that as a material used for forming the first auxiliary electrode 1404, a material that can be a cathode shown in Embodiments 1 to 3 can be used. Further, there is no problem even if these materials are deposited on the bank when the first auxiliary electrode 1404 is formed.

  Next, an organic compound layer 1405 is formed over the first electrode 1402 and the first auxiliary electrode 1404. As a material for forming the organic compound layer 1405, the materials shown in Examples 1 to 3 can be used.

  For example, by forming an organic compound layer that emits red light, an organic compound layer that emits green light, and an organic compound layer that emits blue light, a light-emitting device having three types of light emission can be formed. Since these organic compound layers 1405 are formed along the grooves formed by the banks 1403, they are arranged in stripes in a direction perpendicular to the paper surface.

  Next, a second auxiliary electrode 1406 is formed on the organic compound layer 1405 at a position that does not overlap with the first auxiliary electrode 1404. Note that the second auxiliary electrode 1406 is formed using the same material as the first auxiliary electrode in the same manner.

  Next, the second electrode 1407 is formed over the organic compound layer 1405 and the second auxiliary electrode 1406. Note that the cathode 1407 is formed by an evaporation method. In this embodiment, the second electrode 1407 is formed using a light-blocking material.

  Note that in this embodiment, since the first electrode 1402 is formed using a light-transmitting material, light generated in the organic compound layer 1405 is emitted to the lower side (the substrate 1401 side).

  Next, a glass substrate is prepared as the sealing substrate 1407. In this embodiment, a substrate made of plastic or quartz can be used. Further, a light-shielding substrate can be used.

  The sealing substrate 1409 thus prepared is bonded with a sealant 1410 made of an ultraviolet curable resin. Note that an inner side 1408 of the sealant 1410 is a sealed space and is filled with an inert gas such as nitrogen or argon. It is also effective to provide a hygroscopic agent typified by barium oxide in the sealed space 1408. Finally, an anisotropic conductive film (FPC) 1411 is attached to complete a passive light emitting device.

  Note that this embodiment can be implemented by freely combining materials and the like other than those related to the element structure (active matrix type) shown in Embodiments 1 to 4.

  Since a light-emitting device using a light-emitting element is a self-luminous type, it is superior in visibility in a bright place and has a wide viewing angle as compared with a liquid crystal display device. Therefore, various electric appliances can be completed using the light-emitting device of the present invention.

  As an electric appliance manufactured using the light emitting device manufactured according to the present invention, a video camera, a digital camera, a goggle type display (head mounted display), a navigation system, a sound reproducing device (car audio, audio component, etc.), a notebook type personal computer Computers, game machines, portable information terminals (mobile computers, mobile phones, portable game machines, electronic books, etc.), image playback devices equipped with recording media (specifically, playback of recording media such as digital video discs (DVDs)) And a device provided with a display device capable of displaying the image). In particular, a portable information terminal that frequently sees a screen from an oblique direction emphasizes the wide viewing angle, and thus a light emitting device having a light emitting element is preferably used. Specific examples of these electric appliances are shown in FIG.

  FIG. 15A illustrates a display device, which includes a housing 2001, a support base 2002, a display portion 2003, a speaker portion 2004, a video input terminal 2005, and the like. It is manufactured by using the light emitting device manufactured according to the present invention for the display portion 2003. Since a light-emitting device having a light-emitting element is a self-luminous type, a backlight is not necessary and a display portion thinner than a liquid crystal display device can be obtained. The display devices include all information display devices for personal computers, for receiving TV broadcasts, for displaying advertisements, and the like.

  FIG. 15B illustrates a digital still camera, which includes a main body 2101, a display portion 2102, an image receiving portion 2103, operation keys 2104, an external connection port 2105, a shutter 2106, and the like. It is manufactured by using the light emitting device manufactured according to the present invention for the display portion 2102.

  FIG. 15C illustrates a laptop personal computer, which includes a main body 2201, a housing 2202, a display portion 2203, a keyboard 2204, an external connection port 2205, a pointing mouse 2206, and the like. It is manufactured by using the light emitting device manufactured according to the present invention for the display portion 2203.

  FIG. 15D illustrates a mobile computer, which includes a main body 2301, a display portion 2302, a switch 2303, operation keys 2304, an infrared port 2305, and the like. It is manufactured by using the light emitting device manufactured according to the present invention for the display portion 2302.

  FIG. 15E illustrates a portable image reproducing device (specifically, a DVD reproducing device) provided with a recording medium, which includes a main body 2401, a housing 2402, a display portion A2403, a display portion B2404, and a recording medium (DVD or the like). A reading unit 2405, operation keys 2406, a speaker unit 2407, and the like are included. The display portion A 2403 mainly displays image information and the display portion B 2404 mainly displays character information. The light-emitting device manufactured according to the present invention is used for the display portions A, B 2403 and 2404. Note that an image reproducing device provided with a recording medium includes a home game machine and the like.

  FIG. 15F illustrates a goggle type display (head mounted display), which includes a main body 2501, a display portion 2502, and an arm portion 2503. It is manufactured by using the light emitting device manufactured according to the present invention for the display portion 2502.

  FIG. 15G illustrates a video camera, which includes a main body 2601, a display portion 2602, a housing 2603, an external connection port 2604, a remote control reception portion 2605, an image receiving portion 2606, a battery 2607, an audio input portion 2608, operation keys 2609, and an eyepiece. Part 2610 and the like. It is manufactured by using the light emitting device manufactured according to the present invention for the display portion 2602.

  Here, FIG. 15H shows a mobile phone, which includes a main body 2701, a housing 2702, a display portion 2703, an audio input portion 2704, an audio output portion 2705, operation keys 2706, an external connection port 2707, an antenna 2708, and the like. It is manufactured by using the light emitting device manufactured according to the present invention for the display portion 2703. Note that the display portion 2703 can reduce power consumption of the mobile phone by displaying white characters on a black background.

  If the emission luminance of the organic material is increased in the future, the light including the output image information can be enlarged and projected by a lens or the like and used for a front type or rear type projector.

  In addition, the electric appliances often display information distributed through electronic communication lines such as the Internet or CATV (cable television), and in particular, opportunities to display moving image information are increasing. Since the response speed of the organic material is very high, the light-emitting device is preferable for displaying moving images.

  In addition, since the light emitting portion of the light emitting device consumes power, it is preferable to display information so that the light emitting portion is minimized. Therefore, when a light emitting device is used for a display unit mainly including character information, such as a portable information terminal, particularly a mobile phone or a sound reproduction device, it is driven so that character information is formed by the light emitting part with the non-light emitting part as the background. It is preferable to do.

  As described above, the applicable range of a light-emitting device manufactured using the manufacturing method of the present invention is so wide that electric appliances in various fields can be manufactured using the light-emitting device of the present invention. In addition, the electric appliance of this embodiment can be completed by using the light emitting device manufactured by carrying out the first to eighth embodiments.

3A and 3B each illustrate an element structure of a light-emitting device of the present invention. 3A and 3B each illustrate an element structure of a light-emitting device of the present invention. 3A and 3B each illustrate an element structure of a light-emitting device of the present invention. 3A and 3B each illustrate an element structure of a light-emitting device of the present invention. 8A and 8B illustrate a manufacturing process of a light-emitting device of the present invention. 8A and 8B illustrate a manufacturing process of a light-emitting device of the present invention. 8A and 8B illustrate a manufacturing process of a light-emitting device of the present invention. FIG. 6 illustrates a structure of a light-emitting device of the present invention. 4A and 4B each illustrate a circuit diagram of a pixel portion of a light-emitting device of the present invention. FIG. 6 illustrates a structure of a light-emitting device of the present invention. 4A and 4B each illustrate a circuit diagram of a pixel portion of a light-emitting device of the present invention. 3 is a timing chart when the light emitting device of the present invention is driven with an alternating current. FIG. 6 illustrates an appearance of a light-emitting device of the present invention. 3A and 3B illustrate a passive matrix light-emitting device. The figure which shows an example of an electric appliance.

Claims (6)

In one pixel,
A switching TFT;
A first current control TFT;
A second current control TFT;
A first light emitting element having a first pixel electrode, a first counter electrode, and an organic compound layer formed between the first pixel electrode and the first counter electrode;
A second light-emitting element having a second pixel electrode, a second counter electrode, and the organic compound layer formed between the second pixel electrode and the second counter electrode;
Have
In the switching TFT, one of a source region and a drain region is electrically connected to a source signal line, and the other is connected to a gate electrode of the first current control TFT and a gate electrode of the second current control TFT. Electrically connected, the gate electrode is electrically connected to the gate signal line,
In the first current control TFT, one of a source region and a drain region is electrically connected to the first pixel electrode, and the other is electrically connected to a current supply line.
In the second current control TFT, one of a source region and a drain region is electrically connected to the second pixel electrode, and the other is electrically connected to the current supply line.
The first counter electrode and the second counter electrode are each electrically connected to an AC power source,
The first pixel electrode and the second counter electrode are either an anode or a cathode,
The second pixel electrode and the first counter electrode are the other of an anode or a cathode,
The active matrix display device, wherein the first light emitting element and the second light emitting element each emit light when a forward bias voltage is applied. In one pixel,
A first switching TFT;
A second switching TFT;
A first current control TFT;
A second current control TFT;
A first light emitting element having a first pixel electrode, a first counter electrode, and an organic compound layer formed between the first pixel electrode and the first counter electrode;
A second light-emitting element having a second pixel electrode, a second counter electrode, and the organic compound layer formed between the second pixel electrode and the second counter electrode;
Have
In the first switching TFT, one of a source region and a drain region is electrically connected to a first source signal line, and the other is electrically connected to a gate electrode of the first current control TFT, The gate electrode is electrically connected to the gate signal line,
In the second switching TFT, one of a source region or a drain region is electrically connected to a second source signal line, and the other is electrically connected to a gate electrode of the second current control TFT, A gate electrode is electrically connected to the gate signal line;
In the first current control TFT, one of a source region and a drain region is electrically connected to the first pixel electrode, and the other is electrically connected to a first current supply line.
In the second current control TFT, one of a source region or a drain region is electrically connected to the second pixel electrode, and the other is electrically connected to a second current supply line.
The first counter electrode and the second counter electrode are each electrically connected to an AC power source,
The first pixel electrode and the second counter electrode are either an anode or a cathode,
The second pixel electrode and the first counter electrode are the other of an anode or a cathode,
The active matrix display device, wherein the first light emitting element and the second light emitting element each emit light when a forward bias voltage is applied. In one pixel,
A switching TFT;
A first current control TFT;
A second current control TFT;
A first light emitting element having a first pixel electrode, a first counter electrode, and an organic compound layer formed between the first pixel electrode and the first counter electrode;
A second light-emitting element having a second pixel electrode, a second counter electrode, and the organic compound layer formed between the second pixel electrode and the second counter electrode;
Have
In the switching TFT, one of a source region and a drain region is electrically connected to a source signal line, and the other is connected to a gate electrode of the first current control TFT and a gate electrode of the second current control TFT. Electrically connected, the gate electrode is electrically connected to the gate signal line,
In the first current control TFT, one of a source region and a drain region is electrically connected to the first pixel electrode, and the other is electrically connected to a current supply line.
In the second current control TFT, one of a source region and a drain region is electrically connected to the second pixel electrode, and the other is electrically connected to the current supply line.
The first counter electrode and the second counter electrode are each electrically connected to an AC power source,
The first pixel electrode and the second counter electrode are either an anode or a cathode,
The second pixel electrode and the first counter electrode are the other of an anode or a cathode,
Each of the first light emitting element and the second light emitting element emits light when a forward bias voltage is applied,
The pixel is formed so as to cover a connection portion between the first current control TFT and the first pixel electrode and a connection portion between the second current control TFT and the second pixel electrode. An active matrix, wherein the organic compound layer overlaps the first pixel electrode and the second pixel electrode in one opening formed in the insulating film. Type display device. In one pixel,
A first switching TFT;
A second switching TFT;
A first current control TFT;
A second current control TFT;
A first light emitting element having a first pixel electrode, a first counter electrode, and an organic compound layer formed between the first pixel electrode and the first counter electrode;
A second light-emitting element having a second pixel electrode, a second counter electrode, and the organic compound layer formed between the second pixel electrode and the second counter electrode;
Have
In the first switching TFT, one of a source region and a drain region is electrically connected to a first source signal line, and the other is electrically connected to a gate electrode of the first current control TFT, The gate electrode is electrically connected to the gate signal line,
In the second switching TFT, one of a source region or a drain region is electrically connected to a second source signal line, and the other is electrically connected to a gate electrode of the second current control TFT, A gate electrode is electrically connected to the gate signal line;
In the first current control TFT, one of a source region and a drain region is electrically connected to the first pixel electrode, and the other is electrically connected to a first current supply line.
In the second current control TFT, one of a source region or a drain region is electrically connected to the second pixel electrode, and the other is electrically connected to a second current supply line.
The first counter electrode and the second counter electrode are each electrically connected to an AC power source,
The first pixel electrode and the second counter electrode are either an anode or a cathode,
The second pixel electrode and the first counter electrode are the other of an anode or a cathode,
Each of the first light emitting element and the second light emitting element emits light when a forward bias voltage is applied,
The pixel is formed so as to cover a connection portion between the first current control TFT and the first pixel electrode and a connection portion between the second current control TFT and the second pixel electrode. An active matrix, wherein the organic compound layer overlaps the first pixel electrode and the second pixel electrode in one opening formed in the insulating film. Type display device. In any one of Claims 1 thru | or 4,
An active matrix type display device, wherein the organic compound layer is made of a bipolar material. In any one of Claims 1 thru | or 4,
The organic compound layer includes a first layer having a bipolar property, a second layer having a bipolar property, and a layer serving as a light emitting region formed between the first layer and the second layer; An active matrix display device characterized by comprising a laminated structure.

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