KR20080054547A - Organic light emitting display - Google Patents

Abstract

An organic light emitting diode display according to an exemplary embodiment of the present invention includes a red pixel, a green pixel, and a blue pixel, and each pixel includes a pixel electrode, a common electrode facing the pixel electrode, a light emitting layer positioned between the pixel electrode, and the common electrode, and a light emitting layer. And a translucent member positioned in the direction of the pixel electrode with respect to the pixel electrode and positioned between the translucent member and the common electrode and having at least one of a hole transport layer, a hole injection layer, an electron transport layer, and an electron injection layer. In this case, at least one of the hole transport layer, the hole injection layer, the electron transport layer, and the electron injection layer has a different thickness in the red pixel, the green pixel, and the blue pixel.

Description

Organic light emitting display device {ORGANIC LIGHT EMITTING DEVICE}

1 is an equivalent circuit diagram of an organic light emitting diode display according to an exemplary embodiment of the present invention.

2 is a schematic diagram illustrating an arrangement of a plurality of pixels in an organic light emitting diode display according to an exemplary embodiment of the present invention.

3 is a layout view illustrating three neighboring pixels in the OLED display of FIG. 2.

4 and 5 are cross-sectional views of the organic light emitting diode display of FIG. 3 taken along lines IV-IV'-IV "-IV" 'and V-V.

6 to 8 are graphs showing wavelength characteristics of light emitted from red green and blue pixels in the organic light emitting diode display according to the exemplary embodiment of the present invention.

9 is a layout view illustrating a plurality of neighboring pixels in an organic light emitting diode display according to another exemplary embodiment of the present invention.

<Description of Drawing>

110: insulating substrate 121: gate line

124a: switching control electrode 124b: drive control electrode

129: end of gate line

140: gate insulating film 154a: switching semiconductor

154b: driving semiconductors 163a, 163b, 165a, and 165b: ohmic contacts

171: data line 172: driving voltage line

173a: switching input electrode 173b: drive input electrode

175a: switching output electrode 175b: driving output electrode

179: end of data line 81, 82: contact auxiliary member

85: connecting member

181, 182, 184, 185a, 185b: contact hole

191: pixel electrode 192: translucent member

270: common electrode 361: insulating weir

365: opening 370: light emitting layer

Qs: switching thin film transistor Qd: driving thin film transistor

LD: organic light emitting diode Vss: common voltage

Cst: retaining capacitor

The present invention relates to an organic light emitting display device.

Recently, there is a demand for weight reduction and thinning of a monitor or a television, and according to such a demand, a cathode ray tube (CRT) has been replaced by a liquid crystal display (LCD).

However, the liquid crystal display device requires not only a separate backlight as a light emitting device, but also has many problems in response speed and viewing angle.

Recently, as a display device capable of overcoming such a problem, an organic light emitting diode display (OLED display) has attracted attention.

The organic light emitting diode display includes two electrodes and a light emitting layer interposed therebetween, and electrons injected from one electrode and holes injected from another electrode are combined in the light emitting layer to form excitons. The excitons emit light while releasing energy.

The OLED display is self-luminous and does not require a separate light source, which is advantageous in terms of power consumption, and also has excellent response speed, viewing angle, and contrast ratio.

The organic light emitting diode display may include a plurality of pixels, such as a red pixel, a blue pixel, and a green pixel, and may combine these pixels to display full color.

However, in order to manufacture such an organic light emitting display device, a color filter must be formed in red, green, and blue pixels. To this end, an organic film planarization process is added to increase the manufacturing cost. In addition, in the manufacturing process of stacking organic materials, organic materials remain or gas is released, thereby degrading the characteristics of the device or lowering the yield of the organic light. As a result, display characteristics of the organic light emitting diode display device may be degraded or the service life may be shortened.

Accordingly, an object of the present invention is to solve the problem, and to provide an organic light emitting display device capable of securing device characteristics and process yield.

An organic light emitting diode display according to an exemplary embodiment of the present invention includes a red pixel, a green pixel, and a blue pixel, each pixel including a pixel electrode, a common electrode facing the pixel electrode, a light emitting layer positioned between the pixel electrode and the common electrode, A translucent member positioned in the direction of the pixel electrode with respect to the light emitting layer and inducing a micro process, and an auxiliary layer positioned between the translucent member and the common electrode and having at least one of a hole transport layer, a hole injection layer, an electron transport layer, and an electron injection layer; . In this case, at least one of the hole transport layer, the hole injection layer, the electron transport layer, and the electron injection layer has a different thickness in the red pixel, the green pixel, and the blue pixel.

The hole injection layer preferably has different thicknesses in the red, green, and blue pixels, and the hole injection layer preferably has a thin thickness in the red, green, and blue pixels.

In the red pixel, the green pixel, and the blue pixel, each of the hole injection layers may have a thickness in the range of 600-1,000 Hz, 350-550 Hz, and 100-300 Hz.

Translucent member preferably comprises at least one selected from silver (Ag) or aluminum (Al).

The light emitting layer includes a plurality of sub light emitting layers emitting light of different wavelengths, and it is preferable that the light of different wavelengths combine to emit white light.

The organic light emitting diode display may further include a white pixel, and includes a driving thin film transistor connected to the first electrode and including a polycrystalline semiconductor, and a switching thin film transistor connected to the driving thin film transistor and including an amorphous semiconductor. desirable.

The driving thin film transistor preferably further includes a driving input electrode formed on the polycrystalline semiconductor, a driving output electrode facing the driving input electrode on the polycrystalline semiconductor, and a driving input electrode and a driving control electrode formed on the driving output electrode. .

The switching thin film transistor further includes a switching control electrode formed under the amorphous semiconductor, a switching input electrode formed on the amorphous semiconductor, and a switching output electrode facing the switching input electrode on the amorphous semiconductor and connected to the driving control electrode. desirable.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the other part being "right over" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

First, an organic light emitting diode display according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 1.

1 is an equivalent circuit diagram of an organic light emitting diode display according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the organic light emitting diode display according to the present exemplary embodiment includes a plurality of signal lines 121, 171, and 172 and a plurality of pixels PX connected to the plurality of signal lines 121, 171, and 172 and arranged in a substantially matrix form. ).

The signal line includes a plurality of gate lines 121 for transmitting a gate signal (or scan signal), a plurality of data lines 171 for transmitting a data signal, and a plurality of driving voltage lines for transmitting a driving voltage. and a driving voltage line 172. The gate lines 121 extend substantially in the row direction, and are substantially parallel to each other, and the data line 171 and the driving voltage line 172 extend substantially in the column direction, and are substantially parallel to each other.

Each pixel PX includes a switching thin film transistor (Qs), a driving thin film transistor (Qd), a storage capacitor (Cst), and an organic light emitting diode. , OLED) (LD).

The switching thin film transistor Qs has a control terminal, an input terminal, and an output terminal, and the control terminal is connected to the gate line 121, and the input terminal is a data line ( The output terminal is connected to the driving thin film transistor Qd. The switching thin film transistor Qs transmits a data signal applied to the data line 171 to the driving thin film transistor Qd in response to a scan signal applied to the gate line 121.

The driving thin film transistor Qd also has a control terminal, an input terminal, and an output terminal. The control terminal is connected to the switching thin film transistor Qs, the input terminal is connected to the driving voltage line 172, and the output terminal is organic. It is connected to the light emitting diode LD. The driving thin film transistor Qd flows an output current I _LD whose magnitude varies depending on the voltage applied between the control terminal and the output terminal.

The capacitor Cst is connected between the control terminal and the input terminal of the driving thin film transistor Qd. The capacitor Cst charges a data signal applied to the control terminal of the driving thin film transistor Qd and maintains it even after the switching thin film transistor Qs is turned off.

The organic light emitting diode LD has an anode connected to the output terminal of the driving thin film transistor Qd and a cathode connected to the common voltage Vss. The organic light emitting diode LD displays an image by emitting light having a different intensity depending on the output current I _LD of the driving thin film transistor Qd.

The switching thin film transistor Qs and the driving thin film transistor Qd are n-channel field effect transistors (FETs). However, at least one of the switching thin film transistor Qs and the driving thin film transistor Qd may be a p-channel field effect transistor. In addition, the connection relationship between the thin film transistors Qs and Qd, the capacitor Cst, and the organic light emitting diode LD may be changed.

 Next, the detailed structure of the organic light emitting diode display illustrated in FIG. 1 will be described in detail with reference to FIGS. 2 to 5.

2 is a schematic diagram illustrating an arrangement of a plurality of pixels in an organic light emitting diode display according to an exemplary embodiment of the present invention, and FIG. 3 is a layout view illustrating three neighboring pixels in the organic light emitting diode display of FIG. 2. 5 is a cross-sectional view of the organic light emitting diode display of FIG. 3 taken along a line IV-IV'-IV "-IV" 'and a line VV.

First, referring to FIG. 2, an organic light emitting diode display according to an exemplary embodiment includes a red pixel R displaying red, a green pixel G displaying green, and a blue pixel B displaying blue. They are arranged in sequence in turn. For example, three pixels including the red pixel R, the green pixel G, and the blue pixel B are repeatedly arranged along a row and / or column in a group. However, the arrangement and shape of the pixels may be variously modified, and one pixel group may include white pixels that do not display colors, and the luminance may be improved by further including white pixels.

Next, a detailed structure of the organic light emitting diode display will be described in detail with reference to FIGS. 3 to 5.

FIG. 3 illustrates one pixel group indicated by a dotted line in the organic light emitting diode display of FIG. 2. The three pixels have the same structure as the gate line 121, the data line 171, the driving voltage line 172, the switching thin film transistor Qs and the driving thin film transistor Qd except for the organic light emitting diode. The same components therefore bear the same reference numerals.

A plurality of driving semiconductors 154b and a plurality of linear semiconductor members 151 are formed on an insulating substrate 110 made of transparent glass or plastic.

The driving semiconductor 154b is island-shaped, and the linear semiconductor member 151 mainly extends in the horizontal direction. The driving semiconductor 154b and the linear semiconductor member 151 may be made of a crystalline semiconductor material such as microcrystalline silicon or polycrystalline silicon.

A plurality of gate lines 121, a plurality of driving input electrodes 173b, and a plurality of driving output electrodes 175b are formed on the driving semiconductor 154b and the linear semiconductor member 151. It is.

The gate line 121 transmits a gate signal and mainly extends in a horizontal direction. Each gate line 121 includes an end portion 129 having a large area for connecting the switching control electrode 124a extending upward to another layer or an external driving circuit. When a gate driving circuit (not shown) generating a gate signal is integrated on the substrate 110, the gate line 121 may extend to be directly connected to the gate driving circuit.

The gate line 121 has a plane shape substantially the same as that of the linear semiconductor member 151.

The driving input electrode 173b and the driving output electrode 175b each have an island shape and are separated from the gate line 121. The driving input electrode 173b and the driving output electrode 175b face each other over the driving semiconductor 154b.

The gate line 121, the driving input electrode 173b, and the driving output electrode 175b include aluminum-based metals such as aluminum (Al) and aluminum alloys, silver-based metals such as silver (Ag) and silver alloys, and copper (Cu) and copper. It may be made of copper-based metals such as alloys, molybdenum-based metals such as molybdenum (Mo) or molybdenum alloys, chromium (Cr), tantalum (Ta) and titanium (Ti). However, they may have a multilayer structure including two conductive films (not shown) having different physical properties.

The gate line 121, the driving input electrode 173b, and the driving output electrode 175b are inclined with respect to the surface of the substrate 110, and the inclination angle is preferably about 30 degrees to about 80 degrees.

A plurality of pairs of ohmic contacts 163b and 165b are formed between the driving semiconductor 154b and the driving input electrode 173b and between the driving semiconductor 154b and the driving output electrode 175b, respectively. In addition, a linear semiconductor member 161 is doped with an impurity between the gate line 121 and the linear semiconductor member 151.

The ohmic contacts 163b and 165b and the linear semiconductor member 161 doped with impurities are doped with impurities such as fine crystalline silicon or polycrystalline silicon doped with a high concentration of n-type impurities such as phosphorus (P). It can be made of crystalline semiconductor material.

A gate insulating layer 140 made of silicon oxide (SiO ₂ ) or silicon nitride (SiN _x ) is formed on the gate line 121, the driving input electrode 173b, and the driving output electrode 175b. The gate insulating layer 140 may be a single layer or a plurality of layers including a first layer made of silicon oxide and a second layer made of silicon nitride.

A plurality of switching semiconductors 154a made of hydrogenated amorphous silicon are formed on the gate insulating layer 140. The switching semiconductor 154a has an island shape and overlaps the switching control electrode 124a.

A plurality of data lines 171, a plurality of driving voltage lines 172, and a plurality of electrode members 176 are formed on the switching semiconductor 154a and the gate insulating layer 140.

The data line 171 transmits a data signal and mainly extends in the vertical direction to cross the gate line 121. Each data line 171 has a wide end portion 179 for connection with a plurality of switching input electrodes 173a extending toward the switching control electrode 124a and another layer or an external driving circuit. Include. When a data driving circuit (not shown) generating a data signal is integrated on the substrate 110, the data line 171 may be extended to be directly connected to the data driving circuit.

The driving voltage line 172 transmits a driving voltage and mainly extends in a vertical direction to cross the gate line 121 and is substantially parallel to the data line 171. Each driving voltage line 172 includes a protrusion 177.

The electrode member 176 is an island and is separated from the data line 171 and the driving voltage line 172. The electrode member 176 overlaps the portion facing the switching input electrode 173a (hereinafter referred to as a 'switching output electrode') 175a and the driving semiconductor 154b (hereinafter referred to as a 'drive control electrode') ( 124b). The switching input electrode 173a and the switching output electrode 175a face each other over the switching semiconductor 154a.

The data line 171, the driving voltage line 172, and the electrode member 176 may be made of the same material as the gate line 121 described above.

Side surfaces of the data line 171, the driving voltage line 172, and the electrode member 176 are inclined with respect to the surface of the substrate 110, and the inclination angle is preferably about 30 degrees to about 80 degrees.

A plurality of pairs of ohmic contacts 163a and 165a are formed between the switching semiconductor 154a and the switching input electrode 173a and between the switching semiconductor 154a and the switching output electrode 175a, respectively. The ohmic contacts 163a and 165a have an island shape and may be made of n + hydrogenated amorphous silicon in which impurities such as phosphorus (P) are heavily doped.

A passivation layer 180 made of an inorganic insulating material such as silicon nitride or silicon oxide or an organic insulating material having a low dielectric constant is formed on the data line 171, the driving voltage line 172, and the electrode member 176. .

The passivation layer 180 is formed with a plurality of contact holes 185a and 182 exposing the protrusion 177 of the driving voltage line 172 and the end portion 179 of the data line 171, and the passivation layer 180. ) And the gate insulating layer 140, a plurality of contact holes 181, 184, and 185b exposing the end portion 129 of the gate line 121, the driving input electrode 173b, and the driving output electrode 175b are formed. .

A plurality of pixel electrodes 191, a plurality of connection members 85, and a plurality of contact assistants 81 and 82 are formed on the passivation layer 180.

The pixel electrode 191 is connected to the driving output electrode 175b through the contact hole 185b.

The connecting member 85 is connected to the protrusion 177 of the driving voltage line 172 and the driving input electrode 173b through the contact holes 184 and 185a, respectively, and partially overlaps with the driving control electrode 124b. (storage capacitor) (Cst).

The contact auxiliary members 81 and 82 are connected to the end portion 129 of the gate line 121 and the end portion 179 of the data line 171 through the contact holes 181 and 182, respectively. The contact auxiliary members 81 and 82 compensate for and protect the adhesion between the end portions 129 and 179 of the gate line 121 and the data line 171 and the external device.

The pixel electrode 191, the connection member 85, and the contact assistants 81 and 82 may be made of a transparent conductor such as ITO or IZO.

A plurality of semi-transparent members 192 are formed on the pixel electrode 191, respectively. The translucent member 192 is not particularly limited as long as it is a material having a property of transmitting a portion of light and reflecting a portion of light, and includes about 10 opaque, low-absorbance conductors such as aluminum (Al) or silver (Ag). It can be made translucent by forming into a thin thickness of -100 kPa.

Although only the translucent member 192 is positioned on the pixel electrode 191 in the present exemplary embodiment, the translucent member 192 may be disposed below the pixel electrode 191, and may also be formed on a white pixel (not shown).

An insulating bank 361 is formed on the pixel electrode 191, the connection member 85, and the contact auxiliary members 81 and 82. The weir 361 defines an opening 365 by surrounding the edge of the pixel electrode 191. Weir 361 may be made of an organic insulator such as acrylic resin, polyimide resin, or an inorganic insulator such as silicon oxide (SiO ₂ ) or titanium oxide (TiO ₂ ). It may be, and may be two or more layers. Weir 361 may also be made of a photosensitive material containing black pigment, in which case weir 361 acts as a light shielding member and the forming process is simple.

An organic light emitting member is formed on the bank 361 and the pixel electrode 191.

The organic light emitting member may include an auxiliary layer (not shown) for improving the light emitting efficiency of the light emitting layer in addition to the light emitting layer 370 that emits light.

The light emitting layer 370 may emit white light. Subsequently, a material that uniquely emits light such as red, green, and blue may be stacked to form a plurality of sub light emitting layers (not shown), and the color may be combined to emit white light. In this case, the sub light emitting layer is not limited to being formed vertically, but may be formed horizontally. If the combination is capable of emitting white light, the sub light emitting layer is not limited to red, green and blue, and may be formed in various color combinations.

The light emitting layer 370 may be made of, for example, a high molecular material or a low molecular material, and the high molecular material may include a polyfluorene derivative, a (poly) paraphenylenevinylene derivative, and a polyphenylene. Derivatives, polyvinylcarbazole, polythiophene derivatives, and the like, and the like, and low molecular weight substances such as 9,10-diphenylanthracene (anthracene), tetraphenylbutadiene Butadiene, such as (tetraphenylbutadiene), tetracene (tetracene), distyrylarylene derivatives, benzazole derivatives and carbazole derivatives (carbazole) may be included. Or the above-mentioned high molecular material or low molecular material as a host material, for example, xanthene, perylene, coumarin, rhodamine, rubrene, dish Aminomethylenepyran compound, thiopyran compound, (thia) pyrilium compound, periflanthene derivative, indenoperylene derivative, carbostyryl Dopant such as a compound, nile red, and quinacridone may be used to increase luminous efficiency.

The auxiliary layer includes an electron transport layer (not shown) and a hole transport layer (not shown) for balancing electrons and holes, and an electron injection layer for enhancing the injection of electrons and holes ( electron injecting layer (not shown) and hole injecting layer (hole injecting layer) 371R, 371G, 371B, and the like, and may include one or more layers selected from these. The hole transport layer and the hole injection layer 371R, 371G, and 371B are made of a material having a HOMO level between the work function of the pixel electrode 191 and the highest occupied molecular orbital (HOMO) level of the light emitting layer, and the electron transport layer and the electron injection layer Is made of a material having an LUMO level between the work function of the common electrode 270 and the lower unoccupied molecular orbital (LUMO) level of the light emitting layer. For example, the hole transport layer or the hole injection layer (371R, 371G, 371B) is a diamine, MTDATA ([4,4 ', 4 "-tris (3-methylphenyl) phenylamino] triphenylamine), TPD (N, N'-diphenyl- N, N'-di (3-methylphenyl) -1,1'-biphenyl-4,4'-diamine), 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane (1,1- bis (4-di-p-tolylaminophenyl) cyclohexane), N, N, N ', N'-tetra (2-naphthyl) -4,4-diamino-p-terphenyl (N, N, N', N'-tetra (2-naphthyl) -4,4-diamino-p-terphenyl), 4,4 ', 4-tris [(3-methylphenyl) phenylamino] triphenylamine (4,4', 4-tris [(3-methylphenyl) phenylamino] triphenylamine), polypyrrole, polyaniline, a mixture of polyethylenedioxythiophene and polystyrenesulfonic acid (poly- (3,4-ethylenedioxythiophene: polystyrenesulfonate, PEDOT: PSS) have.

In this case, the thicknesses of the hole injection layers 371R, 371G, and 371B of the red pixel R, the green pixel G, and the blue pixel B are respectively different, and the hole injection layer 371R of the red pixel R is 600-. It is thickest in the range of 1,000 mW, the hole injection layer 371G of the green pixel G has a medium thickness in the range of 350-550 mW, and the hole injection layer 371B of the blue pixel B is the thinnest in the range 100-300 mW. .

The common electrode 270 is formed on the organic light emitting member 370. The common electrode 270 may be made of a metal having a low work function and high reflectivity, such as aluminum or aluminum alloy, gold (Au), platinum (Pt), nickel (Ni), copper (Cu), tungsten (W). ) Or alloys thereof. The common electrode 270 is formed on the entire surface of the substrate, and pairs with the pixel electrode 191 to send a current to the organic light emitting member 370.

Hereinafter, the red pixel R. The green pixel R and the blue pixel B will be described.

The common electrode 270 generates a microcavity effect together with the translucent member 192. The fine resonance effect is to amplify the light of a specific wavelength by repeatedly reflecting the reflective layer and the translucent layer where the light is separated by a predetermined distance. The common electrode 270 serves as a reflective layer and the translucent member 192 serves as a translucent layer.

The common electrode 270 forms a microcavity that greatly modifies the light emission characteristics of the light emitted from the light emitting layer 370, and light emission near the wavelength corresponding to the resonance wavelength of the micro resonance is enhanced through the translucent member 192, and the other Light of the wavelength is suppressed. In this case, the enhancement and suppression of light of a specific wavelength may be determined according to the distance between the common electrode 270 and the translucent member 192. Therefore, light of a specific wavelength may be enhanced and suppressed by controlling the thickness of the light emitting layer 370 and the auxiliary layer (not shown).

In the present invention, as described above, the thicknesses of the hole injection layers 371R, 371G, and 371B of the red pixel R, the green pixel G, and the blue pixel B are adjusted differently, so that the translucent member 192 and the common electrode ( 270 may be adjusted, and through this, the color of light passing through the translucent member 192 may be adjusted differently. Accordingly, the color filter may be omitted by adjusting red, green, and blue light from the red pixel R, the green pixel G, and the blue pixel B, which will be described later with reference to the graph. Let's explain. In the present embodiment, in order to adjust the distance between the translucent member 192 and the common electrode 270, the thickness of the hole transport layer 371R, 371G, and 371B having the best conductivity among the auxiliary layers is adjusted in consideration of the driving voltage and the optical effect. However, the thickness of at least one of the electron transport layer, the electron injection layer, and the hole transport layer can be adjusted.

Meanwhile, in the organic light emitting diode display including the white pixels, the white pixels may be adjusted to emit white light by omitting the translucent members, and the semi-transparent members may be left on the white pixels in order to improve display characteristics.

In the organic light emitting diode display, the switching control electrode 124a connected to the gate line 121, the switching input electrode 173a connected to the data line 171, and the switching output electrode 175a are connected to the switching semiconductor 154a. ) And a switching TFT Qs, and a channel of the switching TFT Qs is formed in the switching semiconductor 154a between the switching input electrode 173a and the switching output electrode 175a. do. The driving control electrode 124b connected to the switching output electrode 175a, the driving input electrode 173b connected to the driving voltage line 172, and the driving output electrode 175b connected to the pixel electrode 191 are driven. A driving TFT Qd is formed together with the semiconductor 154b, and a channel of the driving TFT Qd is formed in the driving semiconductor 154b between the driving input electrode 173b and the driving output electrode 175b. do.

The pixel electrode 191, the organic light emitting member 370, and the common electrode 270 form an organic light emitting diode LD, and the pixel electrode 191 is an anode and the common electrode 270 is a cathode. Alternatively, the pixel electrode 191 becomes a cathode and the common electrode 270 becomes an anode.

As described above, the switching semiconductor 154a is made of an amorphous semiconductor, and the driving semiconductor 154b is made of a crystalline semiconductor. That is, the channel of the switching thin film transistor Qs is formed in the amorphous semiconductor, and the channel of the driving thin film transistor Qd is formed in the crystalline semiconductor.

As described above, in the present invention, the channels of the switching thin film transistor Qs and the driving thin film transistor Qd are formed in semiconductors having different crystal states, thereby satisfying the characteristics required for each thin film transistor.

By forming the channel of the driving thin film transistor Qd in the microcrystalline or polycrystalline semiconductor, it may have high carrier mobility and stability, thereby increasing the amount of current flowing through the light emitting device, thereby increasing luminance. have. In addition, by forming the channel of the driving thin film transistor Qd in the microcrystalline or polycrystalline semiconductor, image sticking is prevented by preventing the Vth shift caused by the continuous application of positive voltage during driving. ) And shortened lifespan.

On the other hand, since the switching thin film transistor Qs plays a role of controlling the data voltage, on / off characteristics are important, and in particular, it is important to reduce the off current. However, since the microcrystalline or polycrystalline semiconductor has a large off current, the data voltage passing through the switching thin film transistor Qs may decrease and cross talk may occur. Accordingly, in the present invention, the switching thin film transistor Qs is formed of an amorphous semiconductor having a small off current, thereby preventing a decrease in data voltage and reducing cross talk.

Although only one switching thin film transistor Qs and one driving thin film transistor Qd are shown in the present embodiment, at least one thin film transistor and a plurality of wirings for driving the thin film transistor are further included. It is possible to prevent or compensate the deterioration of the LD and the driving transistor Qd to prevent the life of the organic light emitting diode display from being shortened.

In the present embodiment, a case in which the light emitted from the light emitting layer is a bottom emission structure that transmits toward the substrate 110 is described. However, a top emission structure in which light emitted from the light emitting layer is transmitted toward the common electrode 170 is also possible. In this case, the pixel electrode 191 may be made of an opaque conductor such as aluminum or an aluminum alloy, gold (Au), platinum (Pt), nickel (Ni), copper (Cu), tungsten (W), or an alloy thereof. The common electrode may be made of a transparent conductor.

As described above, the characteristics of the light emitted from the red pixel, the green pixel, and the blue pixel will be described in detail through the graph.

6 to 8 are graphs illustrating wavelength characteristics of light emitted from red green and blue pixels in the organic light emitting diode display according to the exemplary embodiment of the present invention.

In the present experimental example, the passivation layer 180 was formed to have a thickness of 7,500 ns of silicon nitride, the pixel electrode 191 was formed of a thickness of 900 ns of IZO, and the translucent member 192 was formed of aluminum. In addition, the hole transporting layer was formed to a thickness of 100 kPa, the light emitting layer 370 formed a blue filter, a green filter and a red filter to a thickness of 80 kPa, 40 kPa and 150 kPa, respectively, and the electron injection layer and the electron transport layer is tris (8-hydr) Oxyquinoline) [aluminum tris (8-hydroxyquinoline), Alq3] and LiF (litium fluoride) were formed to a thickness of 350 kW and 7 kW, respectively, and the common electrode 270 formed aluminum to a thickness of 1,600 kW.

In addition, the hole injection layer was formed to a thickness of 200Å to represent blue, the hole injection layer was formed to a thickness of 440Å to represent green, and the hole injection layer was formed to a thickness of 800Å to represent red. As the hole injection layer, “LG101” product provided by “LG Chemistry” was used. The translucent member 192 measured the light that passes through the thickness of 150 kHz, 175 kHz, 200 kHz, 225 kHz, 250 kHz and 275 kHz or the translucent member 192 is not formed.

FIG. 6 is a graph showing the results of measuring the light emitted from the pixel under the condition of not forming the translucent member (without Al) and the condition of forming the translucent member to a thickness of 250 kV. When formed as, the pixel was shown to display light in the red wavelength band.

FIG. 6 is a graph showing the results of measuring the light emitted from the pixel under the condition of not forming the translucent member (without Al) and the condition of forming the translucent member to a thickness of 250 kV. When formed as, the pixel was shown to display light in the red wavelength band.

FIG. 7 is a graph showing the results of measuring the light emitted from the pixel under the condition of not forming a translucent member (without Al) and the condition of forming the translucent member to a thickness of 250 kPa, wherein the hole transport layer has a thickness of about 440 kPa. When formed as, the pixel was shown to display light in the green wavelength band.

FIG. 8 is a graph showing the results of measuring the light emitted from the pixel under the condition of not forming a translucent member (without Al) and the condition of forming the translucent member at a thickness of 200 kV. The pixel was shown to display light in the blue wavelength band.

9 is a layout view illustrating a plurality of neighboring pixels in an organic light emitting diode display according to another exemplary embodiment of the present invention.

Referring to FIG. 9, the organic light emitting diode display according to the present exemplary embodiment does not display red pixels R for displaying red, green pixels G for displaying green, blue pixels B for displaying blue, and colors. White pixels W are alternately arranged in sequence. For example, four pixels including a red pixel R, a green pixel G, and a blue pixel B and a white pixel W are repeatedly arranged along a row and / or column in a group.

In the organic light emitting diode display having the pixel array structure as described above, the present invention applied to the above may be similarly applied.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of the invention.

It is possible to form a semi-transparent member in place of the color filter according to the light emitting material and to display images by displaying various colors using the fine revolving effect, thereby improving the characteristics of the display device, and omit the organic film process. The cost can be minimized and the characteristics of the device can be secured, thereby extending the lifespan of the organic light emitting display device.

Claims (10)

In an organic light emitting diode display including a red pixel, a green pixel, and a blue pixel, Each pixel is Pixel electrode, A common electrode facing the pixel electrode; An emission layer disposed between the pixel electrode and the common electrode; A translucent member positioned in the direction of the pixel electrode with respect to the light emitting layer and inducing a micro process; A sublayer positioned between the translucent member and the common electrode and having at least one of a hole transport layer, a hole injection layer, an electron transport layer, and an electron injection layer, At least one of a hole transport layer, a hole injection layer, an electron transport layer, and an electron injection layer in the red pixel, the green pixel, and the blue pixel has a different thickness. OLED display. In claim 1, The hole injection layer may have a thickness different from that of the red, green, and blue pixels. In claim 1, The hole injection layer of the red pixel, the green pixel, and the blue pixel sequentially has a thin thickness. In claim 3, The hole injection layer of each of the red, green, and blue pixels has a thickness in the range of 600-1,000 mV, 350-550 mV, and 100-300 mV. In claim 1, The translucent member includes at least one selected from silver (Ag) or aluminum (Al). In claim 1, The light emitting layer is It includes a plurality of sub light emitting layer for emitting light of different wavelengths, The light of different wavelengths combine to emit white light OLED display. In claim 1, The organic light emitting diode display further comprises a white pixel. In claim 1, A driving thin film transistor connected to the first electrode and including a polycrystalline semiconductor, and A switching thin film transistor connected to the driving thin film transistor and including an amorphous semiconductor. An organic light emitting display device further comprising. In claim 8, The driving thin film transistor is A driving input electrode formed on the polycrystalline semiconductor, A drive output electrode facing said drive input electrode on said polycrystalline semiconductor, and A drive control electrode formed on the drive input electrode and the drive output electrode; An organic light emitting display device further comprising. In claim 9, The switching thin film transistor A switching control electrode formed under the amorphous semiconductor, A switching input electrode formed on the amorphous semiconductor, and A switching output electrode facing the switching input electrode on the amorphous semiconductor and connected to the driving control electrode An organic light emitting display device further comprising.

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