KR20050087284A - Electro-luminescent display device - Google Patents

Abstract

The present invention relates to an electroluminescent display device in which a pixel defining layer is formed by dispersing a white or black pigment in a light-transmitting insulating material, thereby improving luminous efficiency or increasing contrast. The electroluminescent display according to the present invention is characterized by including an insulating substrate, a first electrode layer, a second electrode layer, an electroluminescent layer, and a pixel defining layer. The first electrode layer is formed on the insulating substrate. The second electrode layer is formed on the first electrode layer. The electroluminescent layer is provided between the first electrode layer and the second electrode layer to emit light. The pixel defining layer is formed on the insulating substrate to partition an area of the electroluminescent layer, and prevents a short circuit between the first electrode layer and the second electrode layer. The pixel defining layer is formed by mixing a colored pigment with a light transmissive material.

Description

Electroluminescent display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescent display having a pixel defining layer. More particularly, the pixel defining layer is formed by dispersing a white or black pigment in a light transmissive material, thereby improving electroluminescence efficiency or increasing contrast. It relates to a display device.

In general, electroluminescent displays are self-luminous displays that electrically excite fluorescent organic compounds to emit light, which can be driven at low voltage, are easy to thin, and are pointed out as problems in liquid crystal display devices such as wide viewing angle and fast response speed. It is attracting attention as the next generation display that can solve the shortcomings. The electroluminescent display may be classified into an inorganic electroluminescent display and an organic electroluminescent display according to whether a material forming the light emitting layer is an inorganic material or an organic material.

Meanwhile, in the organic light emitting display device, an organic film having a predetermined pattern is formed on glass or other transparent insulating substrate, and electrode layers are formed on upper and lower portions of the organic film. The organic film consists of organic compounds. In the organic light emitting display device configured as described above, as the anode and cathode voltages are applied to the electrodes, holes injected from the electrode to which the anode voltage is applied are moved to the light emitting layer via the hole transport layer, and the electrons have a cathode voltage. It is injected from the applied electrode into the light emitting layer via the electron transport layer. In this light emitting layer, electrons and holes recombine to produce excitons, and as the excitons change from the excited state to the ground state, the fluorescent molecules in the light emitting layer emit light to form an image. In the case of a full color organic light emitting display device, full color is realized by including pixels emitting three colors of red (R), green (G), and blue (B) as the organic light emitting diode.

The organic light emitting display device is classified into a passive matrix (PM) type and a passive matrix active matrix (AM) type according to the driving method. In the passive matrix type, the anode and the cathode are simply arranged in columns and rows, respectively, so that the cathode is supplied with a scanning signal from a row driving circuit. At this time, only one row of the plurality of rows is selected. In addition, a data signal is input to each pixel in the column driving circuit. On the other hand, the active matrix type is a thin film transistor (TFT) to control the input signal for each pixel is suitable for processing a large amount of signals are used as a display device for implementing a video.

Among the organic light emitting display devices, an active driving type organic matrix organic light emitting display device includes at least two thin film transistors (TFTs) for each pixel. These thin film transistors are used as switching elements for controlling the operation of each pixel and as driving elements for driving the pixels. The thin film transistor has a semiconductor active layer having a drain region and a source region doped with a high concentration of impurities on a substrate, and a channel region formed between the drain region and the source region, the gate insulating film formed on the semiconductor active layer, and the active layer. A gate electrode formed on the gate insulating film above the channel region, and a drain electrode and a source electrode connected through the contact hole with the drain region, the source region and the interlayer insulating layer therebetween.

As the organic electroluminescent display, an example of a conventional passive matrix organic light emitting device (PMOLED) is disclosed in Korean Patent Publication No. 2002-0029809, which is a conventional active matrix type. An example of an organic matrix organic light emitting device (AMOLED) is disclosed in Korean Laid-Open Patent Publication No. 2003-0042937.

Each of the conventional organic light emitting display devices includes a pixel defining layer (PDL) for inter-electrode insulation and partitioning each pixel. The pixel defining layer in the conventional organic light emitting display device transmits light. Therefore, the light emitted from the organic EL layer is guided in the horizontal direction through the pixel defining layer to be lost, and thus the efficiency of the organic light emitting display device is lowered.

In addition, since the pixel defining layer in the conventional organic light emitting display device transmits light, the external light is reflected by the reflective electrode formed on the opposite side of the light emitting name, thereby reducing the contrast.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electroluminescent display device that can improve luminous efficiency or increase contrast by forming a pixel defining layer by dispersing a white or black pigment in a light transmissive material. It is done.

An electroluminescent display device according to the present invention for achieving the above object is characterized by comprising an insulating substrate, a first electrode layer, a second electrode layer, an electroluminescent layer, and a pixel defining layer.

The first electrode layer is formed on the insulating substrate. The second electrode layer is formed on the first electrode layer. The electroluminescent layer is provided between the first electrode layer and the second electrode layer to emit light. The pixel defining layer is formed on the insulating substrate to partition an area of the electroluminescent layer, and prevents a short circuit between the first electrode layer and the second electrode layer. The pixel defining layer is formed by mixing a colored pigment with a light transmissive material.

An EL display device according to another aspect of the present invention is characterized by including an insulating substrate, a first electrode layer, a second electrode layer, an EL layer, a pixel defining layer, and an insulating partition wall.

The first electrode layer is formed on the insulating substrate. The second electrode layer is formed on the first electrode layer. The electroluminescent layer is provided between the first electrode layer and the second electrode layer to emit light. The pixel defining layer is formed on the insulating substrate to partition an area of the electroluminescent layer, and prevents a short circuit between the first electrode layer and the second electrode layer. The pixel defining layer is formed by mixing a colored pigment with a light transmissive material. The insulating barrier rib is disposed on at least one side of the upper and lower portions of the pixel defining layer and is formed so as not to cover the emission area.

The electroluminescent display according to the present invention is characterized by including an insulating substrate, a first electrode layer, a second electrode layer, an electroluminescent layer, a pixel defining layer, and at least one thin film transistor.

The first electrode layer is formed on the insulating substrate. The second electrode layer is formed on the first electrode layer. The electroluminescent layer is provided between the first electrode layer and the second electrode layer to emit light. The pixel defining layer is formed on the insulating substrate to partition an area of the electroluminescent layer, and prevents a short circuit between the first electrode layer and the second electrode layer. The pixel defining layer is formed by mixing a colored pigment with a light transmissive material. The thin film transistor is formed on an insulating substrate to control and drive light emission of the EL layer.

According to the present invention, by forming the pixel defining layer by dispersing white or black pigment, light emitted in the horizontal direction can be taken out to the front to improve luminous efficiency or to prevent external light reflection to increase contrast.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a plan view illustrating an active matrix organic light emitting display device according to an exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line II of FIG. 1. 3 is a cross-sectional view illustrating an active matrix organic light emitting display device according to another exemplary embodiment of the present invention.

Referring to the drawings, the electroluminescent display device according to the present invention includes the insulating substrates 10 and 40, the first electrode layers 31 and 61, the second electrode layers 33 and 63, the electroluminescent layers 32 and 62, and the pixels. Define layers 16 and 46 and at least one thin film transistor (TFT).

The first electrode layers 31 and 61 are formed on the insulating substrates 10 and 40. The second electrode layers 33 and 63 are formed on the first electrode layers 31 and 61. The electroluminescent layers 32 and 62 are formed between the first electrode layers 31 and 61 and the second electrode layers 33 and 63 to emit light. The pixel defining layers 16 and 46 are formed on the insulating substrates 10 and 40 to partition the regions of the electroluminescent layers 32 and 62, and the first electrode layers 31 and 61 and the second electrode layer 33. 63) is formed by mixing a colored pigment with a light transmissive material. The thin film transistor is mounted on an insulating substrate to control and drive light emission of the EL layer.

The thin film transistor TFT may include gate electrodes 22 and 52 formed in regions corresponding to channel regions of the semiconductor active layers 21 and 51 and the semiconductor active layers 21 and 51 formed on the insulating substrates 10 and 40. And source and drain electrodes 23 and 53 formed of a conductive material to be in contact with the source and drain regions of the semiconductor active layers 21 and 51, respectively.

In addition, the electroluminescent display device is formed to cover the thin film transistor under the first electrode layers 31 and 61, and the first electrode layers 31 and 61 are disposed on any one of the source and drain electrodes 23 and 53. It is preferable to further include passivation films 14, 44 in which via holes 14a, 44a, 54a are formed so as to be electrically connected.

In addition, as shown in FIG. 3, the passivation layer 44 further includes a planarization layer 45 formed of acryl, BCB, polyimide, or the like, and the height of the passivation layer 44 is unevenly formed on the thin film transistor TFT. The passivation layer 44 may be formed on the passivation layer 44 to planarize a surface thereof, thereby making it easier to form the first electrode layer.

Hereinafter, the present invention will be described with reference to the active matrix organic electroluminescent display device shown in FIG. 3 as a specific embodiment thereof.

First, as shown in FIG. 1, an organic light emitting display device according to an exemplary embodiment of the present invention has a plurality of subpixels. A single subpixel is surrounded by a scan line (Scan), a data line (Data), and a driving line (V _dd ), and each subpixel includes a switching TFT (TFT _sw ) for switching and a driving TFT (TFT _dr ) for driving. At least two thin film transistors, one capacitor C _st , and one organic light emitting diode OLED may be formed. The number of thin film transistors and capacitors as described above is not necessarily limited thereto, and of course, a larger number of thin film transistors and capacitors may be provided.

The switching TFT TFT _sw is driven by a scanning signal applied to the scan line Scan to transfer a data signal applied to the data line Data. The driving TFT TFT _dr is in accordance with a data signal transmitted through the switching TFT TFT _sw , that is, through the driving line pads due to the voltage difference V _gs between the gate and the source OLED. Determine the amount of current flowing into. The capacitor C _st stores a data signal transmitted through the switching TFT TFT _sw for one frame.

The cross-sectional structure is as shown in Fig. 3, wherein a buffer layer 41 is formed of SiO ₂ or the like on the insulating substrate 40 of glass material, and as shown in Fig. 1 above the buffer layer 41, A switching TFT TFT _sw , a driving TFT TFT _dr , a capacitor C _st , and an organic light emitting diode OLED are provided. The driving TFT will be described below with reference to the TFT, but the switching TFT also has the same structure. A transparent glass material may be employed as the insulating substrate 40, but is not limited thereto, and a plastic material may be used. When the glass substrate 40 is used, a buffer layer 41 is formed on the substrate 40 to prevent impurity elements from penetrating and to make the surface flat. The buffer layer 41 may be formed of SiO ₂ , may be deposited by a PECVD method, an APCVD method, an LPCVD method, an ECR method, or the like, and may be deposited to about 3000 Å.

As shown in FIG. 3, the driving TFT TFT _dr includes a semiconductor active layer 51 formed on the buffer layer 41, a gate insulating film 42 formed on the semiconductor active layer 51, and a gate insulating film ( 42 has a gate electrode 52 thereon. In addition, the semiconductor active layer 51 has a source and a drain electrode 53 in contact with the contact hole.

The semiconductor active layer 51 may be formed of an inorganic semiconductor or an organic semiconductor, and may be formed to about 500 GPa. When the semiconductor active layer 51 is formed of polysilicon in the inorganic semiconductor, after amorphous silicon is formed, polycrystallization can be performed by various crystallization methods. This active layer has source and drain regions heavily doped with N-type or P-type impurities, and has channel regions therebetween.

The inorganic semiconductor may include CdS, GaS, ZnS, CdSe, CaSe, ZnSe, CdTe, SiC, and silicon materials such as a-Si (amorphous silicon) or poly-Si (poly silicon).

The organic semiconductor may be formed of a semiconducting organic material having a band gap of 1 eV to 4 eV. For example, the organic semiconductor may include a polymer such as polythiophene or a low molecule such as pentacene.

The gate insulating film 42 is provided on the upper surface of the semiconductor active layer 51 by SiO _{2 or the} like, and a predetermined area above the gate insulating film 42 is formed by a conductive metal film such as MoW, Al, Cr, Al / Cu, or the like. 52) is formed. The material forming the gate electrode 52 is not necessarily limited thereto, and various conductive materials such as a conductive polymer may be used as the gate electrode 52. The region where the gate electrode 52 is formed corresponds to the channel region of the semiconductor active layer 51.

An inter-insulator 43 is formed on the gate electrode 52 by SiO ₂ and / or SiN _x , and a contact hole is formed in the interlayer 43 and the gate insulating layer 42. In this state, source and drain electrodes 53 are formed on the interlayer insulating film 43. The source and drain electrodes 53 may be formed of a conductive metal film such as MoW, Al, Cr, Al / Cu, or a conductive polymer.

The structure of the thin film transistor as described above is not necessarily limited thereto, and all of the structures of the conventional general thin film transistor may be used as it is.

A passivation film 44 made of SiN _x or the like is formed on the source and drain electrodes 53, and a planarization film 45 made of acryl, BCB, polyimide, etc. is formed on the passivation film 44. do.

The first electrode layer 61 of the organic light emitting diode OLED is formed on the planarization layer 45, and the first electrode layer 61 passes through the first and second via holes 44a and 45a. And drain electrode 53.

The pixel defining layer 46 is formed on the first electrode layer 61 and the planarization layer 45, and is formed by mixing a color pigment with a light transmissive material. In this case, the light transmissive material is preferably any one of acrylic, epoxy, polyimide. In other words, the pixel defining layer 46 is formed by dispersing a colored pigment in a light-transmitting material, thereby extracting light lost in the horizontal direction to the front to improve luminous efficiency or to prevent external light reflection to increase contrast. have.

Here, there may be an electroluminescent display for extracting light lost in the horizontal direction to the front to improve the luminous efficiency, and an electroluminescent display for increasing contrast by preventing reflection of external light.

First, in order to improve light emission efficiency of the electroluminescent display, the pixel defining layer 46 may be formed by dispersing a white pigment in the light transmissive material. In this case, titanium dioxide (TiO ₂ ) may be used as the white pigment, and the particle size of the white pigment is preferably 300 nm or more and a diameter of 1000 nm or less. This reflects the light emitted from the electroluminescent layer 62 in the horizontal direction in which the pixel defining layer 46 is located, and the white pigment in consideration of the wavelength of the light to be dispersed in order to prevent the light from being dispersed in the horizontal direction. It is because it is preferable that the particle | grains have the range of the size mentioned above.

In addition, in order to increase contrast of the electroluminescent display, the pixel defining layer 46 may be formed by dispersing a black pigment in a light transmissive material. In this case, the black pigment is preferably a non-conductive carbonaceous material. This is to allow the pixel defining layer 46 to be black in order to absorb the light in order to prevent reflection of light incident from the outside through the pixel defining layer 46.

In addition, a pixel definition opening 46a is formed in the pixel definition layer 46. After the pixel defining opening 46a is formed, the organic layer 62 and the second electrode layer 63 of the organic light emitting diode OLED are formed on the pixel defining opening 46a.

The organic light emitting diode OLED displays predetermined image information by emitting red, green, and blue light according to the flow of current, and is connected to the source and drain electrodes 53 of the TFT to supply positive power therefrom. The first electrode layer 61 to be supplied, the second electrode layer 63 provided to cover all pixels, and supplying negative power, and disposed between the first electrode layer 61 and the second electrode layer 63 to emit light. Is composed of an electroluminescent layer 62.

The first electrode layer 61 and the second electrode layer 63 are spaced apart from each other by the electroluminescent layer 62 at a predetermined interval, and emit light from the electroluminescent layer 62 by applying voltages having different polarities to the electroluminescent layer 62. Let this be done.

The electroluminescent layer 62 may be a low molecular or polymer organic layer. When the low molecular organic layer is used, a hole injection layer (HIL), a hole transport layer (HTL), and an organic emission layer (EML) may be used. ), An electron transport layer (ETL), an electron injection layer (EIL), or the like, may be formed by stacking a single or a complex structure, and the usable organic material may be copper phthalocyanine (CuPc). , N, N-di (naphthalen-1-yl) -N, N'-diphenyl-benzidine (N, N'-Di (naphthalene-1-yl) -N, N'-diphenyl-benzidine: NPB), Various applications are possible, including tris-8-hydroxyquinoline aluminum (Alq3). These low molecular weight organic layers are formed by the vacuum deposition method.

In the case of the polymer organic layer, the structure may include a hole transporting layer (HTL) and a light emitting layer (EML). In this case, PEDOT is used as the hole transporting layer, and PPV (Poly-Phenylenevinylene) and polyfluorene are used as the emitting layer. Polymer organic materials such as (Polyfluorene) are used and can be formed by screen printing or inkjet printing.

The electroluminescent layer as described above is not necessarily limited thereto, and various embodiments may be applied.

The first electrode layer 61 functions as an anode electrode, and the second electrode layer 63 functions as a cathode electrode. Of course, the polarities of the first electrode layer 61 and the second electrode layer 63 are reversed. It may be. Hereinafter, an embodiment in which the first electrode layer 61 is an anode will be described.

In an active matrix type organic light emitting display device, there may be a case of top emission emitting light in a direction in which an organic light emitting diode (OLED) is formed and a bottom emission emitting light in a direction in which a thin film transistor is formed. Embodiments in which the first electrode layer 61 and the second electrode layer 63 can be different for the case for improving the efficiency and the case for increasing the contrast, respectively.

First, in the electroluminescent display in which the pixel defining layer 46 is formed by dispersing the white pigment in the light transmissive material in order to improve the luminous efficiency of the electroluminescent display, the first electrode layer 61 in the case of the back emission. ), A transparent electrode may be used, and a high reflection electrode may be used as the second electrode layer 63. In the case of top emission, a high reflection electrode may be used as the first electrode layer 61, and a transparent electrode may be used as the second electrode layer 63.

That is, a transparent electrode is used as an electrode layer positioned on the light emitting surface side so that light generated in the electroluminescent layer is transmitted through the electrode to be emitted to the light emitting surface, and a high reflection electrode is used as an electrode layer located on the opposite side of the light emitting surface. As much of the light generated in the light emitting layer as possible can be emitted to the light emitting surface without spilling to the opposite side. In addition, the pixel defining layer formed on the side surface of the electroluminescent layer may have a white color to prevent light emitted from the electroluminescent layer from leaking to the side surface. Accordingly, light emitted from the EL layer may be emitted to only the light emitting surface as much as possible, thereby improving light emission efficiency of the EL display device.

In addition, in the electroluminescent display in which the pixel defining layer 46 is formed by dispersing black pigment in the light transmissive material in order to improve the contrast of the electroluminescent display, the first electrode layer 61 is used in the case of the back emission. As a transparent electrode, a low reflection electrode may be used as the second electrode layer 63. In the case of top emission, a low reflection electrode may be used as the first electrode layer 61 and a transparent electrode may be used as the second electrode layer 63.

That is, a transparent electrode is used as an electrode layer positioned on the light emitting surface side so that light generated in the electroluminescent layer can pass through the electrode to be emitted to the light emitting surface, and a low reflection electrode is used as an electrode layer located on the opposite side of the light emitting surface. It is possible to suppress the light incident from the reflection on the light emitting surface. In addition, the pixel defining layer formed on the surface excluding the electroluminescent layer may be black so that light incident from the outside may be absorbed and prevented from being reflected again. As a result, light incident from the outside may not be reflected and emitted again in the direction of the light emitting surface, thereby improving contrast of the EL display device.

In this case, when the contrast is improved by applying the black pixel defining layer and the low reflection anode to the electroluminescent display, a circular polarizer attached to the light emitting surface is unnecessary in the conventional electroluminescent display in order to increase the contrast. Therefore, the thickness and weight can be reduced, and the cost can be saved.

Here, the transparent electrode may be made of ITO, IZO, ZnO, or In ₂ O ₃ , the high reflection electrode used as the first electrode layer 61 is Ag, Mg, Al, Pt, Pd, Au, Ni, After forming a reflective film with Nd, Ir, Cr, a compound thereof, or the like, ITO, IZO, ZnO, or In ₂ O ₃ can be formed thereon.

On the other hand, in the case where the second electrode layer 63 is used as the cathode electrode, the high reflection electrode used as the second electrode layer 63 is a metal having a small work function, that is, Li, Ca, LiF / Ca, LiF / Al, Al, Mg, and compounds thereof may be formed by full deposition.

In addition, the low reflection electrode may be formed as a metal insulator hybrid layer (MIHL) by co-bonding a material forming the transparent electrode and a material used for the high reflection electrode. That is, the low reflection electrode may be formed by co-depositing a material forming the high reflection electrode on the material forming the transparent electrode to have a concentration gradient in the thickness direction.

In this case, the high reflection electrode is typically formed to have a reflectance of 90% or more, and the low reflection electrode is preferably formed to have a reflectance of 10% or less.

4 is a cross-sectional view illustrating a passive matrix organic light emitting display device according to another exemplary embodiment of the present invention.

Referring to the drawings, a passive matrix type organic light emitting display device includes an insulating substrate 70, a first electrode layer 91, a second electrode layer 93, an electroluminescent layer 92, a pixel defining layer 76, and insulation. The partition wall 77 is provided. Here, in the active matrix type organic light emitting display device shown in FIGS. 1 to 3, the means for improving luminous efficiency or enhancing contrast are equally applicable, and the same names and similar elements are used for the same applicable components. Reference numerals are used and detailed descriptions thereof are omitted.

The first electrode layer 91 is formed on the insulating substrate 70. The second electrode layer 93 is formed on the first electrode layer 91. The electroluminescent layer 92 is formed between the first electrode layer 91 and the second electrode layer 93 so as to emit light. The pixel defining layer 76 is formed on the insulating substrate 70 to partition an area of the EL layer 92, and prevents a short circuit between the first electrode layer 91 and the second electrode layer 93. It is formed by mixing a colored pigment with a permeable material. The insulating partition 77 is formed on at least one side of the upper and lower portions of the pixel defining layer 76 so as not to cover the light emitting region 70b and is formed as the non-light emitting region 70a.

The pixel defining layer 76 is preferably formed by dispersing a white pigment in a light transmissive material in order to improve luminous efficiency. Alternatively, the pixel defining layer 76 may be formed by dispersing a black pigment in a light transmissive material in order to improve contrast. In this case, as the light transmitting material, the white pigment, and the black pigment, the same ones as in the active matrix organic electroluminescent display device shown in FIGS. 1 to 3 may be used.

The insulating barrier 77 may be formed on the upper surface of the pixel defining layer 76 and may be formed of the same material as the pixel defining layer 76. The insulating partition 77 is formed to a height high enough to support the shield of the deposition mask when forming an organic light emitting film for forming a color among the cathode or the organic film using the deposition mask. In this case, the sum of the heights of the pixel defining layer 76 and the insulating partition 77 should be at least greater than the sum of the heights of the second electrode layer 93 and the electroluminescent film 92.

The insulating partition 77 may be formed in various patterns along the pattern in which the pixel defining layer 76 is formed. For example, when the pixel defining layer 76 is formed in a lattice shape, the pixel defining layer 76 may be formed as an insulating partition wall 77 in a closed curve along the periphery of the light emitting region partitioned by the pixel defining layer 76. Along the 76 may be formed of the insulating partition wall 22 in the form of a lattice. In addition, it may be formed on a dot that is not connected to each other at a predetermined portion, or may be formed on a stripe shape.

In the passive and active matrix type organic light emitting display device as described above, organic films, including the light emitting layer, have a very weak limit to moisture. Therefore, in order to protect the light emitting layer from external moisture and to protect the display area in the display device from external physical shocks, an encapsulation is included using a substrate or a metal cap including a desiccant 79. It is desirable to.

Hereinafter, a method of manufacturing an active matrix organic light emitting display device according to an embodiment of the present invention will be described with reference to FIGS. 5 to 9.

Method 600 of manufacturing an active matrix organic electroluminescent display includes manufacturing a thin film transistor substrate (S500); Forming a first electrode layer on the thin film transistor substrate (S610); Forming a pixel defining layer on the entire surface of the thin film transistor substrate (S620); Forming an electroluminescent film on the first electrode layer and the pixel defining layer (S640); Forming a second electrode layer on the electroluminescent film and the pixel defining layer (S650); And forming an encapsulation by sealing the ones formed on the thin film transistor substrate including a desiccant (S660). The method of manufacturing the active matrix organic light emitting display device is a method of manufacturing the active matrix organic light emitting display device of FIGS. 1 to 3. For details, refer to the description of FIGS. 1 to 3.

The manufacturing of the thin film transistor substrate (S500) may include forming a buffer layer on the insulating substrate (S501), forming a semiconductor active layer (S502), forming a gate insulating film (S503), and a gate Forming an electrode (S504), forming an interlayer insulating film (S505), forming a source and drain electrode (S506), forming a passivation film (S507), and forming a planarization film (S508) It is provided with.

In this case, in the forming of the pixel defining layer (S620), it is preferable to form a white or black pigment by dispersing the entire surface of the thin film transistor substrate.

FIG. 5 illustrates a buffer layer formed on the insulating substrate 40 (S501), a thin film transistor TFT formed thereon, and a planarization layer 45 coated thereon (S508). Formation of the thin film transistor (TFT) includes forming a semiconductor thin film on the substrate 40 and patterning the semiconductor active layer 51 by doping ions (S501 and S502); After covering the gate insulating layer 42 on the substrate 40 and the semiconductor active layer 51 (S503), forming the gate electrode 52 in a region having a narrower width than a region corresponding to the plurality of semiconductor active layers (S504). )Wow; After the interlayer insulating layer 43 is covered on the gate insulating layer 42 and the gate electrode (S505), a contact hole is formed in the ion doped region, a conductive thin film is formed on the substrate, and then patterned to form a source electrode on the contact hole. The drain electrode 53 is formed (S506). In addition, when the passivation film 44 and the planarization film 45 are formed on the thin film transistor TFT formed as described above, and the thin film transistor substrate is manufactured (S500), the thin film transistor is formed as shown in FIG. 5. Here, the process of forming the thin film transistor TFT is known in the art and overlaps the above description, and thus a detailed description thereof will be omitted.

6, a second via hole 45a is formed in the planarization film 45 so as to communicate with the first via hole 44a of the passivation film 44 by a photolithography process or other perforation. Then, a conductive thin film is formed on the planarization film 45, and then patterned to form a first electrode layer 61 of the organic light emitting diode OLED. The electrode layer 61 is formed of the first and second via holes 44a. It is connected to any one of the source and drain electrodes 53 through 45a.

Thereafter, as illustrated in FIG. 7, the pixel defining layer 46 is formed on the planarization layer 45 and the first electrode layer 61. The pixel defining layer 46 should be made of an insulating material such as acryl, polyimide, BCB, or the like, and particularly preferably made of a polyimide material having heat resistance and high resistance. In particular, in order to improve luminous efficiency or contrast according to the present invention, the pixel defining layer is preferably formed by dispersing a white or black pigment in a light transmissive material such as polyimide.

The pixel defining layer 46 is formed of a high resistance insulating film so as to completely cover the first electrode layer 61. The pixel defining layer 46 is patterned to form an opening 46a exposing at least a portion of the first electrode layer 61. Can be completed.

Next, as shown in FIG. 8, in the opening 46a, the electroluminescent layer 62 is sealed on the first electrode layer 61 so that at least a portion of the side of the electroluminescent layer 62 is sealed to the entire side of the pixel defining layer 46. Is applied so that the first electrode layer 61 is electrically insulated from the outside. As a result, the pixel defining layer 46 insulates the first electrode layer 61 from the outside, and in particular, electrically insulates the first electrode layer 61 and the second electrode layer 63. Thereafter, when the second electrode layer 63 made of a conductive material is coated on the electroluminescent layer 62 and the pixel defining layer 46, an organic electroluminescent display as shown in FIG. 3 is formed.

10 is a flowchart schematically illustrating a method of manufacturing a passive matrix organic electroluminescent display device according to another exemplary embodiment of the present invention.

Referring to the drawings, the method 700 of manufacturing a passive matrix organic light emitting display device includes: forming a first electrode layer 91 on an insulating substrate 70 (S710); Forming a pixel defining layer 76 over the insulating substrate 70 (S720); Forming a barrier rib 77 on the pixel defining layer 76 (S730); Forming an electroluminescent film (92) on the first electrode layer (91) and the barrier rib (77); Forming a second electrode layer (93) on the electroluminescent film (92) (S750); And forming the encapsulation 78 by sealing the ones formed on the insulating substrate 70 including the desiccant 79 (S760). The method of manufacturing the passive matrix organic light emitting display device is a method of manufacturing the passive matrix organic light emitting display device of FIG. 4. See the description of FIG. 4 for related information.

In this case, the pixel defining layer 76 should be made of a light-transmitting insulating material such as acrylic, polyimide, BCB, and particularly preferably made of a polyimide material having properties of heat resistance and high resistance. In particular, in order to improve luminous efficiency or contrast according to the present invention, the pixel defining layer is preferably formed by dispersing a white or black pigment in a light transmissive material such as polyimide.

In the present specification, the preferred embodiment of the electroluminescent display device according to the present invention will be mainly described in the organic electroluminescent display device. However, the electroluminescent display according to the present invention, in addition to the organic electroluminescent display, includes a pixel defining layer that partitions a light emitting area and prevents short circuit between electrodes. By dispersing the light emitting device, the light emitting device can be applied to other display devices that can improve light emission efficiency or reduce reflection of external light to improve contrast.

According to the electroluminescent display device according to the present invention, by forming the pixel defining layer by dispersing the white pigment, it is possible to extract the light lost in the horizontal direction to the entire surface to improve the luminous efficiency.

In addition, by forming the pixel defining layer by dispersing the black pigment, the external light reflection can be prevented to increase the contrast.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, it is merely an example, and those skilled in the art may realize various modifications and equivalent other embodiments therefrom. I can understand. Accordingly, the true scope of protection of the invention should be defined only by the appended claims.

1 is a plan view illustrating an active matrix organic electroluminescent display device according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line II of FIG. 1.

3 is a cross-sectional view illustrating an active matrix organic light emitting display device according to another exemplary embodiment of the present invention.

4 is a cross-sectional view illustrating a passive matrix organic light emitting display device according to another exemplary embodiment of the present invention.

5 to 8 are cross-sectional views schematically illustrating a method of manufacturing the active matrix organic electroluminescent display of FIGS. 1 to 3.

9 is a flowchart schematically illustrating a method of manufacturing the active matrix organic electroluminescent display of FIGS. 5 to 8.

10 is a flowchart schematically illustrating a method of manufacturing the passive matrix organic electroluminescent display of FIG. 4.

<Description of the symbols for the main parts of the drawings>

10, 40, 70: insulating substrate, 11, 41: buffer layer,

12, 42: gate insulating film, 13, 43: interlayer insulating film,

14, 44: passivation film, 14a, 44a: first via hole,

45: planarization film, 45a: second via hole,

16, 46, 76: pixel defining layer, 46a: pixel defining opening,

21, 51: semiconductor active layer, 22, 52: gate electrode,

23, 53: source and drain electrodes, 31, 61, 91: first electrode layer,

32, 62, 92: electroluminescent layer, 33, 63, 93: second electrode layer.

77: bulkhead, 78: bag,

79: Desiccant.

Claims (13)

Insulating substrate; A first electrode layer formed on the insulating substrate; A second electrode layer formed on the first electrode layer; An electroluminescent layer formed between the first electrode layer and the second electrode layer to emit light; And Forming a pixel defining layer formed on the insulating substrate to partition a region of the electroluminescent layer and to prevent a short circuit between the first electrode layer and the second electrode layer, wherein the pixel defining layer is formed by mixing a color pigment with a light transmissive material. An electroluminescent display characterized by the above-mentioned. The method of claim 1, And at least one side of an upper portion and a lower portion of the pixel defining layer, wherein the insulating partition wall is formed so as not to cover the light emitting area. The method of claim 1, And at least one thin film transistor formed on the insulating substrate to control and drive light emission of the electroluminescent layer. The method according to any one of claims 1 to 3, And the light transmissive material is any one of acryl, epoxy, and polyimide. The method according to any one of claims 1 to 3, And the colored pigment is a white pigment. The method of claim 5, And the white pigment is made of titanium dioxide. The method of claim 5, An electroluminescent display device, wherein the white pigment has a particle size of 300 nm or more and a diameter of 1000 nm or less. The method of claim 5, A transparent electrode is used as the first electrode layer, and a high reflection electrode having a reflectance of 90% or more is used as the second electrode layer. The method of claim 5, A high reflection electrode having a reflectance of 90% or more is used as the first electrode layer, and a transparent electrode is used as the second electrode layer. The method according to any one of claims 1 to 3, And the colored pigment is a black pigment. The method of claim 10, And the black pigment is made of a non-conductive carbonaceous material. The method of claim 10, A transparent electrode is used as the first electrode layer, and a low reflection electrode having a reflectance of 10% or less is used as the second electrode layer. The method of claim 10, A low reflection electrode having a reflectance of 10% or less is used as the first electrode layer, and a transparent electrode is used as the second electrode layer.