JP4589830B2 - Flexible display and manufacturing method thereof - Google Patents

Description

  The present invention relates to a flexible display and a manufacturing method thereof, and more particularly to a flexible display applicable to an organic EL display or a liquid crystal display using a plastic film as a substrate and a manufacturing method thereof.

  Display devices such as organic EL (Electroluminescence) displays and liquid crystal displays are rapidly expanding their applications to information equipment. In recent years, a flexible display using a plastic film as a substrate has attracted attention. Such flexible displays can be used not only for ultra-thin and lightweight mobile devices that can be rolled up and stored, but also for large displays.

  However, the plastic film has a low rigidity and a low thermal deformation temperature, and thus is likely to undergo thermal deformation such as warping and expansion / contraction in a manufacturing process involving heat treatment. For this reason, in a manufacturing method in which various elements are formed directly on a plastic film, conditions such as a manufacturing process involving heat treatment are limited, and high-precision alignment becomes difficult, so that an element substrate having desired characteristics is manufactured. It may not be possible.

  In order to avoid such problems, a transparent electrode, a color filter layer, and the like are aligned and formed with high accuracy on a heat-resistant and rigid glass substrate without restricting manufacturing conditions, There is a method of manufacturing an element substrate for a liquid crystal display device by transferring and forming this transfer layer on a plastic film (Patent Document 1).

  In addition, in order to obtain a display having excellent display characteristics, active driving in which a driving transistor is incorporated for each pixel is required. The flexible display requires a flexible TFT element that can follow the bending, and there is a possibility that sufficient reliability cannot be obtained with a low-temperature polysilicon TFT or an amorphous silicon TFT as a conventional driving transistor. For this reason, organic TFTs that use a flexible organic semiconductor layer that can follow bending as an active layer have attracted attention as driving transistors for flexible displays.

  In Patent Document 2, a gate electrode, a gate insulating film, an organic semiconductor layer, and a source / drain electrode are sequentially formed on a substrate, and an organic EL element is formed on an anode connected to the drain electrode. A method of manufacturing an EL display is described.

In Patent Document 3, an isolation layer is formed on a heat-resistant substrate, an organic TFT composed of a gate electrode, a gate insulating film, an organic semiconductor layer, and a source / drain is formed thereon, and then an organic TFT is formed. A method of transferring from a heat-resistant substrate to a surface substrate (plastic substrate) is described.
JP 2003-131199 A JP 2003-255857 A JP 2003-318195 A

  By the way, the organic semiconductor layer and the organic EL layer have a problem in that their performance deteriorates or eventually becomes nonfunctional in a photolithography and etching process that involves processing such as an organic solvent, water, plasma, electron beam, or heat treatment. .

  In Patent Documents 2 and 3 described above, since it is necessary to pattern the source / drain after forming the organic semiconductor layer, there is a possibility that performance degradation of the organic semiconductor layer in the photolithography process may become a problem.

  Thus, a manufacturing method of a flexible display using an organic TFT using a plastic film as a substrate has not been sufficiently established, and a desired organic TFT or organic EL element can be stably provided on a plastic film with a high yield. A method of forming is eagerly desired.

  The present invention has been created in view of the above-described problems, and is manufactured at a high yield without causing any problems. A flexible display using a plastic film as a substrate and having an organic TFT and a method for manufacturing the same The purpose is to provide.

  In order to solve the above-described problems, the present invention relates to a flexible display, which is an active matrix type flexible display in which a TFT is provided for each pixel, and includes a plastic film and an adhesive layer formed on the plastic film. A barrier insulating layer formed on the adhesive layer; an organic active layer, a gate insulating layer, and a gate electrode are formed in order from the bottom; and a source electrode and a drain. A TFT having a structure in which an electrode is electrically connected to the organic active layer, a pixel electrode formed above the barrier insulating layer and electrically connected to the drain electrode of the TFT, and the pixel of each pixel An organic EL layer including a light-emitting layer formed on each pixel electrode; a metal electrode formed on the organic EL layer; and the metal And having a sealing layer covering the electrode.

  The flexible display of the present invention is manufactured by a transfer technique, and is first configured such that a release layer and an organic active layer are on top on a temporary substrate (such as a glass substrate) having heat resistance and rigidity. A transfer layer composed of a TFT, a pixel electrode connected to its drain electrode, and a barrier insulating layer is formed with desired film characteristics without restricting manufacturing conditions. Next, the transfer layer is transferred and formed in a state where the transfer layer is turned upside down on the plastic film via the adhesive layer. Subsequently, after the peeling layer is removed, an organic EL layer including a light emitting layer is formed on each pixel electrode of each pixel. Furthermore, after metal electrodes are formed on the organic EL layer, they are covered with a sealing layer.

  In the above-described invention, the light emitting layer may be composed of a red (R) light emitting layer, a green (G) light emitting layer, and a blue (B) light emitting layer, and a white light emitting layer is used as the light emitting layer. A color filter layer may be formed. Alternatively, in order to improve color saturation, the light emitting layer is composed of light emitting layers of three primary colors, and further a color filter layer is formed, thereby combining the color filter layer and the EL light emission of the three primary colors to achieve full color. You may do it.

  Unlike the present invention, in a structure in which a TFT having an organic active layer, a pixel electrode, and an organic EL layer are directly formed on a plastic film, a photolithography process is required after the organic active layer is formed. Not only is the performance of the active layer deteriorated, but when a low-resistance pixel electrode (ITO) is formed, there is a problem that the plastic film is thermally deformed due to heat treatment at a high temperature.

  However, in the present invention, the photolithography patterning step (the step of forming the TFT gate electrode, source electrode and drain electrode, and pixel electrode) that adversely affects the organic active layer and the organic EL layer is performed by the organic active layer and the organic EL layer. Is performed on a temporary substrate before forming. Furthermore, after the organic active layer connected to the source electrode and the drain electrode is formed on the temporary substrate by mask vapor deposition or the like, a barrier insulating layer is formed to obtain a transfer layer. Thereafter, after the transfer layer is transferred onto the plastic film in an upside down state, an organic EL layer is formed on the topmost exposed pixel electrode by mask vapor deposition or the like. By adopting such a manufacturing method, there is no possibility that the characteristics of the organic active layer and the organic EL layer are deteriorated by various processes in the photolithography process.

  As described above, in the flexible display of the present invention, the organic active layer and the organic EL layer for TFT are formed on the plastic film at a high yield without causing any problems, thereby reducing the manufacturing cost and improving the reliability. be able to.

  The flexible display of the present invention can be applied to an active matrix liquid crystal display by omitting the organic EL layer and the like.

  Further, in order to solve the above-described problems, the present invention relates to a method for manufacturing a flexible display, which is a method for manufacturing an active matrix type flexible display in which a TFT is provided for each pixel, and includes a release layer on a temporary substrate. And a gate electrode, a gate insulating layer, and an organic active layer are formed in order from the bottom on the release layer, and a source electrode and a drain electrode are electrically connected to the organic active layer. Forming a TFT and a pixel electrode electrically connected to the drain electrode of the TFT; forming a barrier insulating layer on or above the TFT; and on the barrier insulating layer, The step of adhering the plastic film through the adhesive layer and the temporary substrate on the plastic film by peeling from the interface with the peeling layer A step of transferring and forming the TFT, the pixel electrode, and the peeling layer upside down via the adhesive layer; and removing the peeling layer to form a part of the TFT and the pixel electrode. A step of exposing, a step of forming an organic EL layer including a light emitting layer on the pixel electrode of each pixel, a step of forming a metal electrode on the organic EL layer, and a seal covering the metal electrode And a step of forming a stop layer.

  By using the manufacturing method of the present invention, a flexible display having the above-described configuration can be easily manufactured.

  In the above-described invention, the organic active layer and the organic EL layer for TFT are formed by mask vapor deposition, an inkjet method, or printing. When employing the inkjet method or printing, before the organic active layer and the organic EL layer are formed, an organic insulating layer pattern in which an opening is provided in a portion where the organic active layer and the organic EL layer are formed is formed. The organic active layer and the organic EL layer are aligned and formed in the openings in a state where the layer pattern becomes a partition.

  As described above, according to the present invention, an active matrix type organic EL display or liquid crystal display including an organic TFT using a plastic film as a substrate is manufactured with a high yield without causing any problems.

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

(First embodiment)
1-5 is sectional drawing which shows the manufacturing method of the flexible display of 1st Embodiment of this invention, FIG. 6 is sectional drawing which shows the flexible display (organic EL display) of 1st Embodiment of this invention. In the first embodiment, an example in which the present invention is applied to an organic EL display will be described. As shown in FIG. 1A, the flexible display manufacturing method according to the first embodiment of the present invention first prepares a glass substrate 20 as a temporary substrate, and a release layer made of polyimide resin or the like on the glass substrate 20. 22 is formed.

  Thereafter, as shown in FIG. 1B, a conductive layer made of gold (Au) having a film thickness of, for example, 100 nm is formed on the peeling layer 22, and the conductive layer is patterned by photolithography and etching. Thus, the source electrode 24a and the drain electrode 24b of the switching TFT (Thin Film Transistor) (hereinafter referred to as Sw-TFT) and the source electrode 24x and the drain electrode 24y of the driving TFT (hereinafter referred to as Dr-TFT) are provided. And are formed.

Subsequently, after a transparent conductive layer such as an ITO (Indium Tin Oxide) layer having a film thickness of, for example, 150 nm is formed on the release layer 22, the source electrodes 24a and 24x, and the drain electrodes 24b and 24y by a sputtering method, The transparent conductive layer is patterned by photolithography and etching. Thereby, as shown in FIG. 1C, the pixel electrode 26 electrically connected to the drain electrode 24y for the Dr-TFT is formed on the peeling layer 22. Note that the pixel electrode 26 may be formed so as to overlap the end portion of the drain electrode 24y for the Dr-TFT. In this embodiment, since the ITO layer to be the pixel electrode 26 is formed on the heat-resistant glass substrate 20, a sputtering method with a film forming temperature of about 200 ° C. can be employed. As a result, the pixel electrode 26 (ITO) is formed with low resistance (specific resistance value: 3 × 10 ⁻⁴ Ω · cm or less) electrical characteristics.

  Next, as shown in FIG. 1D, a protective layer 28 made of an acrylic resin or the like covering the source electrodes 24a and 24x, the drain electrodes 24b and 24y, and the pixel electrode 26 is formed.

  Next, as shown in FIG. 2A, a conductive layer made of tantalum (Ta), aluminum (Al), chromium (Cr), IZO, ITO, or the like was formed on the protective layer 28 by vapor deposition or sputtering. Later, the conductive layer is patterned by photolithography and etching. As a result, the Sw-TFT gate electrode 30a is formed on the protective layer 28 between the Sw-TFT source electrode 24a and the drain electrode 24b so as to overlap each other. At the same time, the gate electrode 30b for the Dr-TFT is formed on the protective layer 28 between the source electrode 24x and the drain electrode 24y for the Dr-TFT so as to overlap each other.

  As described above, the source electrodes 24a and 24x, the drain electrodes 24b and 24y, the pixel electrode 26, and the gate electrodes 30a and 30b are formed on the glass substrate 20 with high precision and miniaturized by photolithography.

Subsequently, as shown in FIG. 2B, a gate insulating layer 32 that covers the gate electrodes 30a and 30b is formed. As the gate insulating layer 32, a silicon oxide layer (SiO _X layer) or a tantalum oxide layer (Ta ₂ O ₅ layer) having a film thickness of, for example, 200 nm is used, and these insulating layers are formed by CVD or sputtering. The

  Next, as shown in FIG. 2C, by processing the gate insulating layer 32 and the protective layer 28 by photolithography and etching, the depths reaching the source electrode 24a and the drain electrode 24b for the Sw-TFT respectively. A first via hole 32x and a second via hole 32y having a depth reaching each of the source electrode 24x and the drain electrode 24y for the Dr-TFT are formed.

  Subsequently, as shown in FIG. 3A, the Sw-TFT organic active layer 36a electrically connected to the Sw-TFT source electrode 24a and the drain electrode 24b through the first via hole 32x is gated. It is formed on the insulating layer 32. At the same time, an organic active layer 36b for Dr-TFT that is electrically connected to the source electrode 24x and the drain electrode 24y for Dr-TFT is formed on the gate insulating layer 32 through the second via hole 32y.

  As a material of each organic active layer 36a, 36b, an organic semiconductor such as pentacene, sexithiophene, or polythiophene is used. The organic active layers 36a and 36b are formed on the gate insulating layer 32 so as to be filled in the first and second via holes 32x and 32y by mask vapor deposition, and the film thickness thereof is, for example, about 50 nm. Mask vapor deposition is a method of forming a pattern simultaneously with film formation by moving a shadow mask with high accuracy in a vacuum vapor deposition apparatus. Patterned organic active layers 36a and 36b are used without using photolithography. Can be formed. Therefore, the performance of the organic active layers 36a and 36b is not deteriorated by wet processing or plasma in the photolithography process.

  The organic active layers 36a and 36b may be formed after the first and second via holes 32x and 32y are filled with a conductive material such as a conductive paste, and the organic active layers 36a and 36b may be formed via the first and second via holes 32x and 32y. The active layers 36a and 36b may be electrically connected to the source electrodes 24a and 24x and the drain electrodes 24b and 24y.

  Thus, the Sw-TFT 5 including the gate electrode 30a, the gate insulating layer 32, the source electrode 24a, the drain electrode 24b, and the organic active layer 36a connected to the source electrode 24a and the drain electrode 24b is obtained. In addition, the Dr-TFT 6 including the gate electrode 30b, the gate insulating layer 32, the source electrode 24x, the drain electrode 24y, and the organic active layer 36b connected to the source electrode 24x and the drain electrode 24y is obtained.

Next, as shown in FIG. 3B, a barrier insulating layer 37 covering the organic active layers 36a and 36b is formed. As the barrier insulating layer 37, an inorganic insulating layer such as a silicon oxide layer (SiO _X ), a silicon nitride layer (SiN _X ), or a silicon oxynitride layer (SiON) that can block the intrusion of water vapor is preferably used. It is formed by sputtering. Two or more layers selected from the SiO _X layer, the SiN _X layer, and the SiON layer may be stacked.

  After that, as shown in FIG. 3C, the plastic film 40 is disposed on the upper surface of the barrier insulating layer 37 in FIG. Further, the adhesive layer 34 is cured by heat treatment, and the plastic film 40 is bonded onto the structure shown in FIG. As the plastic film 40, a polyethersulfone film or a polycarbonate film having a film thickness of 100 to 200 μm is preferably used.

  Subsequently, as shown in FIG. 3C, a roll 29 is fixed to one end of the plastic film 40, and the glass substrate 20 is peeled off while the roll 29 is rotated. At this time, it peels along the interface (A part of FIG.3 (c)) of the glass substrate 20 and the peeling layer 22, and the glass substrate 20 is discarded.

  As a result, as shown in FIG. 4A, the adhesive layer 34, the barrier insulating layer 37, the organic active layers 36a and 36b, the gate insulating layer 32, and the gate electrodes 30a and 30b are formed on the plastic film 40 in this order from the bottom. Then, the protective layer 28, the source electrodes 24a and 24x, the drain electrodes 24b and 24y, the pixel electrode 26, and the peeling layer 22 are transferred and formed.

  After that, as shown in FIG. 4B, the release layer 22 is removed by oxygen gas plasma or the like. Thereby, the upper surfaces of the source electrodes 24a and 24x, the drain electrodes 24b and 24y, and the pixel electrode 26 are exposed.

  As described above, in this embodiment, the TFTs 5 and 6 are formed on the glass substrate 20 so that the organic active layers 36a and 36b are on the upper side, and then transferred and formed on the plastic film 40 in an inverted state. Is adopted. Accordingly, since the organic active layers 36a and 36b are not exposed on the upper side of the plastic film 40 but are embedded in the lower side, the organic active layers 36a and 36b may be damaged in various processing steps thereafter. Disappears.

  Subsequently, as shown in FIG. 4C, a hole transport layer 38 having a film thickness of, for example, 30 nm is selectively formed on the pixel electrode 26 by mask vapor deposition. As the hole transport layer 38, α-NPD, which is an aromatic tertiary amine derivative, is preferably used. Further, as shown in FIG. 4C, a low molecular light emitting layer 42 having a film thickness of, for example, 70 nm is selectively formed on the hole transport layer 38 by mask deposition. In the present embodiment, an example in which a light emitting layer of three primary colors is formed to form a full color is illustrated, so that the three primary colors (red (R), green (G), blue (B)) are described later with reference to FIG. A red light emitting layer, a green light emitting layer, and a blue light emitting layer are formed on the hole transport layer 34 of each pixel portion. A pixel portion (sub-pixel) of three primary colors constitutes a pixel as a display unit.

  As the low molecular light emitting layer 42, a host material mixed with a doping material is used, and the doping material (molecule) emits light. Examples of the host material include Alq3 and a distyrylarylene derivative (DPVBi), and examples of the doping material include green-emitting coumarin 6 and red-emitting DCJTB.

  Subsequently, as shown in FIG. 4C, an electron transport layer 44 is formed on the light emitting layer 42 by mask vapor deposition. As the electron transport layer 44, quinolinol aluminum complex (Alq3) or the like is preferably used.

  Thereby, the organic EL layer 3 comprised by the positive hole transport layer 38, the light emitting layer 42, and the electron carrying layer 44 is obtained.

  Note that only one of the hole transport layer 38 and the electron transport layer 44 may be formed, or both the hole transport layer 38 and the electron transport layer 44 may be omitted.

  Further, as shown in FIG. 4D, a metal electrode 46 is selectively formed on the electron transport layer 44 by mask vapor deposition. As the metal electrode 46, a lithium fluoride / aluminum (LiF / Al) laminated film or the like is preferably used. The film thickness of the LiF layer is set to 0.2 to 1 nm, and the film thickness of the Al layer is set to 100 to 200 nm. .

  Thereby, the organic EL element 2 comprised by the pixel electrode 26, the organic EL layer 3, and the metal electrode 46 is obtained.

  Thus, in this embodiment, since the process of forming the organic active layers 36a and 36b and the organic EL layer 3 and the subsequent processes do not use photolithography, the organic active layers 36a and 36b and the organic EL layer 3 can be There is no possibility that the performance is deteriorated by various processes in the lithography process.

After that, as shown in FIG. 5, a sealing layer 48 that covers the organic EL element 2, the Sw-TFT 5, and the Dr-TFT 6 is formed. As the sealing layer 48, a silicon oxide layer (SiO _X ), a silicon nitride layer (SiN _X ), or the like is used. For example, the sealing layer 48 is formed by low-temperature CVD at a film forming temperature of about 100 ° C. Or it is good also as the sealing layer 48 by sticking the resin film in which the moisture-proof layer was formed.

  Thus, the flexible organic EL display 1 according to the first embodiment of the present invention is completed.

  As described above, in the flexible display manufacturing method of the present embodiment, the patterning process by photolithography (the source electrodes 24a and 24x, the drain electrodes 24b and 24y, the negative effects on the organic active layers 36a and 36b and the organic EL layer 3). The step of forming the pixel electrode 26, the gate electrodes 30a and 30b, and the via holes 32x and 32y) is performed on the glass substrate 20 before the organic active layers 36a and 36b and the organic EL layer 3 are formed. Furthermore, the organic active layers 36a and 36b connected to the source electrodes 24a and 24x and the drain electrodes 24b and 24y and the barrier insulating layer 37 covering them are formed on the glass substrate 20 to obtain a transfer layer. Thereafter, the transfer layer is transferred onto the plastic film 40 while being inverted upside down, and then the organic EL element 2 is formed on the pixel electrode 26 by mask vapor deposition.

  By adopting such a manufacturing method, there is no possibility that the characteristics of the organic active layers 36a and 36b and the organic EL layer 3 are deteriorated by various processes in the photolithography process. Moreover, after the transfer layer is transferred to the plastic film 40 (the state shown in FIG. 4B), the source electrodes 24a and 24x, the drain electrodes 24b and 24y, and the pixel electrode 26 are exposed at the top, and the organic active layers 36a and 36a are exposed. Since 36b is buried below, a photolithography process is performed after the transfer and before the formation of the organic EL element 2 (the process between FIG. 4B and FIG. 4C). However, there is no possibility of damaging the organic active layers 36a and 36b.

  Accordingly, the insulating layer covering the Sw-TFT 5 and the Dr-TFT 6 and having an opening on the pixel electrode 26 can be patterned by photolithography. Thereby, even if the metal electrode 46 of the organic EL element 2 is formed on the entire surface of the plastic film 40, no problem occurs, and the degree of freedom in designing the organic EL display can be widened.

  As described above, in the present embodiment, an organic EL display including an organic TFT using a plastic film as a substrate can be stably manufactured with a high yield. Furthermore, since the barrier insulating layer 37 capable of blocking water vapor is formed under the organic active layers 36a and 36b, it is possible to prevent water vapor from the outside air and water in the plastic film 40 from entering the organic active layer 36, and to reliably A highly organic EL display can be obtained.

  FIG. 6 illustrates the three primary color pixel portions (red pixel portion (R), green pixel portion (G), and blue pixel portion (B)) of the flexible display of the first embodiment. As shown in FIG. 6, in the flexible organic EL display 1 of the first embodiment, a plastic film 40 is used as a substrate, and a barrier insulating layer 37 is formed thereon via an adhesive layer 34. An organic active layer 36a of the Sw-TFT 5 and an organic active layer 36b of the Dr-TFT 6 are formed on the barrier insulating layer 37 of the pixel portions (R), (G), and (B) of the three primary colors. A gate insulating layer 32 and gate electrodes 30a and 30b are formed on the organic active layers 36a and 36b of the pixel portions (R), (G), and (B) of the three primary colors. Further, a protective layer 28 is formed on each gate electrode 30a, 30b.

  Further, on the protective layer 28 of the pixel portions (R), (G), and (B) of the three primary colors, the source electrode 24a and the drain electrode 24b for the Sw-TFT 5 and the source electrode 24x for the Dr-TFT 6 and A drain electrode 24y and a pixel electrode 26 electrically connected to the drain electrode 24y for the Dr-TFT 6 are provided.

  The organic active layer 36a of each Sw-TFT 5 in each of the pixel portions (R), (G), and (B) of the three primary colors is passed through the first via hole 32x provided in the gate insulating layer 32 and the protective layer 28. The source electrode 24a and the drain electrode for the Sw-TFT 5 are electrically connected to 24b, respectively. Similarly, the organic active layer 36b of each Dr-TFT 6 is electrically connected to the source electrode 24x and the drain electrode 24y of the Dr-TFT 6 through the second via hole 32y provided in the gate insulating layer 32 and the protective layer 28, respectively. It is connected.

  In this way, the source electrodes 24a and 24x, the drain electrodes 24b and 24y, the gate electrodes 30a and 30b, the gate insulating layer 32, and the organic activity are added to the pixel portions (R), (G), and (B) of the three primary colors. Sw-TFT 5 and Dr-TFT 6 constituted by layers 36a and 36b are respectively arranged.

  Further, an organic layer composed of a hole transport layer 38, light emitting layers 42R, 42G, and 42B and an electron transport layer 44 is formed on each pixel electrode 26 of each of the three primary color pixel portions (R), (G), and (B). Each EL layer 3 is formed. A red light-emitting layer 42R, a green light-emitting layer 42G, and a blue light-emitting layer 42B are provided corresponding to the three primary color pixel portions (R), (G), and (B), respectively.

  Further, a metal electrode 46 is formed on each organic EL layer 3 of each of the three primary color pixel portions (R), (G), and (B), and each pixel portion (R), (G), (B). Further, the organic EL element 2 constituted by the pixel electrode 26, the organic EL layer 3, and the metal electrode 46 is provided. On the organic EL element 2, the Dr-TFT 6, and the Sw-TFT 5, a sealing layer 48 that covers them is formed.

  FIG. 7 is a diagram showing an equivalent circuit of one pixel portion of the flexible display according to the first embodiment of the present invention, and FIG. 8 is a plan view of one pixel portion of the flexible display according to the first embodiment of the present invention seen from the plane direction. It is.

  As shown in FIGS. 7 and 8, in the flexible organic EL display 1 of the first embodiment, the metal electrode 46 (cathode) of the organic EL element 2 is connected to the ground (GND) 66, and the pixel electrode of the organic EL element 2 is displayed. 26 (anode) is connected to the drain electrode 24 y of the Dr-TFT 6. The source electrode 24 x of the Dr-TFT 6 is connected to a power supply (Vdd) line 60. Further, a storage capacitor Cs is formed between the gate electrode 30 b of the Dr-TFT 6 and the power supply (Vdd) line 60. Further, the drain electrode 24 b of the Sw-TFT 5 is connected to the gate electrode 30 b of the Dr-TFT 6, and the source electrode 24 a of the Sw-TFT 5 is connected to the data line 62. Further, the gate electrode 30 a of the Sw-TFT 5 is connected to the scanning line 64.

  The equivalent circuit of FIG. 7 operates as follows. First, when the potential of the scanning line 64 is selected and a writing potential is applied to the scanning line 64, the Sw-TFT 5 is turned on to charge or discharge the storage capacitor Cs, and the gate potential of the Dr-TFT 6 becomes the writing potential. Next, when the potential of the scanning line 64 is set to a non-selected state, the scanning line 64 and the Dr-TFT 6 are electrically disconnected, but the gate potential of the Dr-TFT 6 is stably held by the storage capacitor Cs.

  Then, the current flowing through the Dr-TFT 6 and the organic EL element 2 has a value corresponding to the gate-source voltage of the Dr-TFT 6, and the organic EL element 2 continues to emit light with the luminance corresponding to the current value.

  An active matrix organic EL display can be configured by arranging a plurality of pixels having such a configuration in a matrix and repeating writing through the data lines 62 while sequentially selecting the scanning lines 64. In this manner, light of a predetermined color is emitted from the light emitting layers 42R, 42G, and 42B of the pixel portions (R), (G), and (B) to the outside, and a color image is obtained (FIG. 6). Arrow direction).

  In addition, the problem which organic TFT has is the dispersion | variation in the characteristic of organic TFT. In particular, if the threshold voltage (Vth) of the Dr-TFT 6 varies, the illuminance varies within the display screen. Accordingly, a countermeasure is taken to compensate for variations in the threshold voltage (Vth) of the Dr-TFT 6 by providing a compensation circuit in the equivalent circuit of FIG. As such a compensation circuit, there are a current programming method and a voltage programming method in which two transistors are added (reference material: 2003 FPD technology, Electronic Journal Publishing (2003)).

  Although a technique for adding a compensation circuit to a circuit using a low-temperature polysilicon TFT or an amorphous silicon TFT has been developed, the same effect can be obtained by adding a compensation circuit to a circuit using an organic TFT as in this embodiment. can get.

  In the first embodiment described above, a color filter is provided between the protective layer 28 and the gate insulating layer 32 or between the gate insulating layer 32 and the barrier insulating layer 37 as in the second embodiment described below. It is good also as a form in which the layer was provided. In the case of this embodiment, since the color filter layer is combined with the red (R), green (G), and blue (B) EL light emission, the color saturation can be improved.

(Second Embodiment)
FIG. 9 is a sectional view showing a flexible display (organic EL display) according to the second embodiment of the present invention. In the second embodiment, a white light emitting layer is used as the light emitting layer of the organic EL layer, and a full color is obtained by combining color filters. 9, the same elements as those in FIG. 6 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 9, in the flexible organic EL display 1a of the second embodiment, the red light emitting layer 42R, the green light emitting layer 42G, and the blue light emitting layer 42B are all replaced with the white light emitting layer 42 in FIG. 6 of the first embodiment. It is a form. Color filter layers 52R, 52G, and 52B are formed between the protective layer 28 and the gate insulating layer 32 of the pixel portions (R), (G), and (B) of the three primary colors, respectively. A red color filter layer 52R is disposed in the red pixel portion (R), a green color filter layer 52G is disposed in the green pixel portion (G), and a blue color filter layer 52B is disposed in the blue pixel portion (B). Is configured. In the second embodiment, white light is emitted from the white light emitting layer 42 of each pixel unit (R), (G), and (B), and a color image passes through the three primary color filter layers 52R, 52G, and 52B. Is obtained (the direction of the arrow in FIG. 9).

  In order to manufacture the flexible display of the second embodiment, the pixel electrodes corresponding to the three primary color pixel portions (R), (G), and (B) after the step of FIG. 1D of the first embodiment. A red color filter layer 52R, a green color filter layer 52G, and a blue color filter layer 52B may be sequentially formed on the protective layer 28 on the layer 26. Each of the color filter layers 52R, 52G, and 52B is formed by patterning, for example, a pigment dispersion type photosensitive coating film by photolithography. The color filter layers 52R, 52G, and 52B may be formed at any stage before the organic active layers 36a and 36b are formed. Therefore, it may be formed between the gate insulating layer 32 and the barrier insulating layer 37.

  The flexible organic EL display 1a of the second embodiment has the same effects as those of the first embodiment.

(Third embodiment)
10-13 is sectional drawing which shows the manufacturing method of the flexible display of 3rd Embodiment of this invention in order, FIG. 14 is sectional drawing which shows the flexible display of 3rd Embodiment of this invention. In the first embodiment, the organic active layer and the organic EL layer are formed by mask vapor deposition. However, in the third embodiment, the organic active layer and the organic EL layer are formed by an inkjet method or printing. In the third embodiment, detailed description of the same steps as those in the first embodiment is omitted.

  First, as shown in FIG. 10A, after the release layer 22 is formed on the glass substrate 20, the mask metal layer 25 having an opening 25 x provided in a required portion is patterned on the release layer 22. As a material of the mask metal layer 25, aluminum (Al), silver (Ag), or the like is used. The opening 25x of the mask metal layer 25 is formed in a portion corresponding to a region where a pixel electrode (light emitting layer) for TFT to be formed later is formed.

  Next, as shown in FIG. 10B, after a coating film such as a polyimide resin is formed on the release layer 22 and the mask metal layer 25 by spin coating or printing, heat treatment is performed at a temperature of 200 to 300 ° C. By curing the coating film, the first organic insulating layer 27a having a film thickness of, for example, 2 to 5 μm is obtained. As the first organic insulating layer 27a, a material that can be etched by plasma of gas mainly containing oxygen gas such as PMMA (polymethyl methacrylate) resin and acrylic resin is used in addition to polyimide resin. In the present embodiment, since the first organic insulating layer 27a accompanied by the heat treatment is formed on the glass substrate 20, the plastic film that finally becomes the substrate is not thermally deformed.

  Subsequently, as shown in FIG. 10C, the steps of FIG. 1B to FIG. 2C of the first embodiment are performed to form the first embodiment on the organic insulating layer 27a. Similarly, the source electrodes 24a and 24x, the drain electrodes 24b and 24y, the pixel electrode 26 connected thereto, the protective layer 28, the gate electrodes 30a and 30b, and the gate insulating layer 32 are sequentially formed, and then the source electrodes 24a and 24x and the drain electrode are formed. First and second via holes 32x and 32y having a depth reaching the electrodes 24b and 24y are formed.

  Next, as shown in FIG. 11A, a second organic insulating layer pattern 39 having an opening 39x in a portion where an organic active layer is to be formed is formed on the gate insulating layer 32. The second organic insulating layer pattern 39 provided with the opening 39x may be formed by patterning photosensitive polyimide, or mask metal as described in the first organic resin layer pattern 27 forming step described later. Various layers (polyimide resin, PMMA resin, or acrylic resin) may be formed by patterning using a layer.

Thereafter, the upper surface of the structure of FIG. 11A is treated with plasma of a gas containing fluorine atoms such as CF ₄ to make the surface of the second organic insulating layer pattern 39 water-repellent, and the via holes 32x and 32y The exposed portions of the source electrodes 24a and 24x and the drain electrodes 24b and 24y exposed to the surface are made hydrophilic.

  Next, as shown in FIG. 11 (b), the coating liquid 35 for forming the organic active layer of the TFT is injected into the opening 39 x of the second organic insulating layer pattern 39 from the nozzle 31 of the ink jet apparatus (not shown). Each is coated to form a coating film. At this time, the coating liquid 35 is filled in the first and second via holes 32 x and 32 y and is formed on the gate insulating layer 32 in the opening 39 x of the second organic insulating layer pattern 39. Further, the coating film is baked at a temperature of 100 to 200 ° C. and dried to obtain an organic active layer 36 a for Sw-TFT and an organic active layer 36 b for Dr-TFT. As the coating liquid 35 for forming the organic active layers 36a and 36b, a liquid containing an organic semiconductor material such as pentacene, sexithiophene, or polythiophene described in the first embodiment is used. At this time, since the surface of the second organic insulating layer pattern 39 is water-repellent, even if the nozzle 31 of the inkjet device is slightly displaced from the opening 39x of the second organic insulating layer pattern 39, the coating liquid 35 Flows toward the opening 39x and accumulates in the opening 39x. In this way, the Sw-TFT 5 and the Dr-TFT 6 having the same structure as that of the first embodiment are obtained.

  Next, as shown in FIG. 11C, a barrier insulating layer 37 that covers the organic active layers 36a and 36b is formed as in the first embodiment.

  Subsequently, as shown in FIG. 12A, after the plastic film 40 is bonded to the upper surface of the barrier insulating layer 37 in FIG. 11C via the adhesive layer 34 by the same method as in the first embodiment, The glass substrate 20 is peeled off while rotating the roll 29 fixed to one end of the plastic film 40. At this time, it peels along the interface (A part of Fig.12 (a)) of the glass substrate 20 and the peeling layer 22, and the glass substrate 20 is discarded.

  Thus, as shown in FIG. 12B, the adhesive layer 34, the barrier insulating layer 37, the organic active layers 36a and 36b, the second organic insulating layer pattern 39, and the gate insulating layer are formed on the plastic film 40 in order from the bottom. 32, the gate electrodes 30a and 30b, the protective layer 28, the source electrodes 24a and 24x, the drain electrodes 24b and 24y, the pixel electrode 26, the first organic insulating layer 27a, the mask metal layer 25, and the release layer 22 are transferred and formed. .

  Thereafter, as shown in FIG. 10C, the peeling layer 22 is removed by plasma of oxygen gas, and the first organic insulating layer 27a is etched by plasma of oxygen gas using the exposed mask metal layer 25 as a mask. Thereby, the first organic insulating layer pattern 27 provided with the opening 27x is obtained. By using oxygen gas plasma in an isotropic etching apparatus, the first organic insulating layer 27a (polyimide resin or PMMA resin) is isotropically etched from the mask metal layer 25 to form a forward tapered shape (from the upper side to the lower side). As a result, the first organic insulating layer pattern 27 having the opening portion 27x whose width increases toward the side) is obtained. In the present embodiment, the first organic insulating layer pattern 27 having a forward taper shape with a taper angle θ (FIG. 12C) of 60 ° or less (preferably 60 ° to 30 °) can be obtained.

When an acrylic resin is used as the first organic insulating layer 27a, the first organic insulating layer 27a is etched by plasma of a mixed gas obtained by adding 2 to 5% of a gas containing fluorine atoms such as CF _{4 to} oxygen gas.

  Subsequently, as shown in FIG. 13A, the mask metal layer 25 is selectively removed with respect to the base layer. For example, when an Al layer is used as the mask metal layer 25, wet etching using a solution containing phosphoric acid is employed, and the mask metal layer 25 is removed without damaging the pixel electrode 26 and the like.

  As a result, the first organic insulating layer pattern 27 having a forward tapered shape is exposed, and the first organic insulating layer pattern 27 is formed in a state where the opening 27x is provided on the pixel electrode 26.

After that, the upper surface of the structure in FIG. 13A is exposed to plasma of a gas containing fluorine atoms (such as CF ₄ , SF _6, or CHF ₃ ). As a result, fluorine atoms adhere to the upper surface and side surfaces of the first organic insulating layer pattern 27 so that the first organic insulating layer pattern 27 exhibits water repellency that repels liquid. At the same time, the exposed surface of the pixel electrode 26 is hydrophilic. It becomes sex.

  In the step of patterning the first organic insulating layer 27a with oxygen plasma, the step of removing the mask metal layer 25 with chemicals, and the step of plasma processing with a fluorine-based gas, the organic active layers 36a and 36b exist below. However, since the pixel electrode 26, the source electrodes 24a and 24x, and the drain electrodes 24b and 24y are blocked, there is no possibility that the organic active layers 36a and 36b are damaged by these treatments.

  Next, as shown in FIG. 13B, a thiophene-based conductive polymer (PEDOT / PET) is formed on the pixel electrode 26 in the opening 27x of the first organic insulating layer pattern 27 from the nozzle 31 of the ink jet apparatus (not shown). The hole transport layer 38 is formed by applying a coating solution 33 of PSS), baking at a temperature of 100 to 200 ° C., and drying.

  Further, as shown in FIG. 13B, the coating liquid 33 for forming the light emitting layer is applied onto the hole transport layer 38 in the opening 27x of the first organic insulating layer pattern 27 by the same ink jet method. The light emitting layer 42 is formed by coating, baking at a temperature of 100 to 200 ° C., and drying. Although only one pixel portion is shown in FIG. 13B, the hole transport of each of the three primary color pixel portions (R), (G), and (B) is the same as in the first embodiment. A red light emitting layer, a green light emitting layer, and a blue light emitting layer are formed on the layer 38, respectively.

  As a material of the light emitting layer for forming the light emitting layer of the three primary colors, there are a π-conjugated polymer light emitting material and a dye-containing polymer light emitting material. More specifically, the π-conjugated polymer-based light emitting material includes polyfluorene (PF) dielectric (red, green, blue), poly-Spiro dielectric (red, green, blue), polyparaphenylene dielectric, or Examples include polythiophene dielectrics.

On the other hand, as a dye-containing polymer-based light-emitting material, a dye-dispersed PVK (red, green, blue) that is a light-emitting material in which a phosphorescent or fluorescent low-molecular dye is dispersed in polyvinyl carbazole (PVK), Ir (ppy) ₃ , or the like There are side chain-incorporated PVKs (red, green, and blue), which are phosphorescent polymers in which the phosphor group is incorporated into the side chain of PVK.

  The above-described materials are dissolved in a solvent such as xylene, toluene, chloroform, anisole, tetradecane, dichloroethane, chlorobenzene, benzene, dichlorobenzene, and the coating liquid (ink) for forming each color light emitting layer is prepared.

  In this way, the organic EL layer 3a composed of the hole transport layer 38 and the light emitting layer 42 is obtained. As in the first embodiment, the electron transport layer may be further formed on the light emitting layer 42, or only one of the hole transport layer 38 and the electron transport layer may be formed. It is good. Alternatively, both the hole transport layer 38 and the electron transport layer may be omitted.

  In the third embodiment, since the organic EL layer 3a is formed by an ink jet method, the performance of the organic EL layer 3a is not deteriorated by various processes in the photolithography process as in the first embodiment.

  Further, when the hole transport layer 38 and the light emitting layer 42 are formed by the ink jet method, the surface of the first organic insulating layer pattern 27 is water-repellent. 1 Aligned in a self-aligned manner in the opening 27 x of the organic insulating layer 27.

  Note that the organic EL layer 3a may be formed by screen printing instead of the ink jet method.

  Next, as shown in FIG. 13C, a calcium / aluminum (Ca / Al) laminated film, a barium (Ba) film, or a barium / aluminum (Ba / Al) laminated film is formed on the light emitting layer 42 by mask vapor deposition. A metal electrode 46 is formed. Thereby, the organic EL element 2a comprised by the pixel electrode 26, the organic EL layer 3a, and the metal electrode 46 is obtained. Since the first organic insulating layer pattern 27 is formed on the Sw-TFT 5 and the Dr-TFT 6, the metal electrode 46 may be formed over the entire surface.

  After that, as shown in FIG. 14, a sealing layer 48 that covers the organic EL element 2a is formed as in the first embodiment.

  Thus, the flexible organic EL display 1b according to the third embodiment is completed.

  As shown in FIG. 14, in the flexible organic EL display 1b of the third embodiment, a plastic film 40 is used as a substrate, and a barrier insulating layer 37 is formed thereon with an adhesive layer 34 interposed therebetween. In the opening 39x of the second organic insulating layer pattern 39 on the barrier insulating layer 37, an organic active layer 36a of the Sw-TFT 5 and an organic active layer 36b of the Dr-TFT 6 are formed. The second organic insulating layer pattern 39 functions as a partition wall when the organic active layers 36a and 36b are formed by an inkjet method, and the organic active layers 36a and 36b are arranged with high positional accuracy.

  On each organic active layer 36a, 36b, a gate insulating layer 32, a gate electrode 30a of Sw-TFT 5, and a gate electrode 30b for Dr-TFT 6 are respectively formed in order, and on each gate electrode 30a, 30b. A protective layer 28 is formed. On the protective layer 28, the source electrode 24 a and the drain electrode 24 b for the Sw-TFT 5, the source electrode 24 x and the drain electrode 24 y for the Dr-TFT 6, and the drain electrode 24 y for the Dr-TFT 6 were electrically connected. A pixel electrode 26 is formed. The organic active layers 36a and 36b are electrically connected to the source electrodes 24a and 24x and the drain electrodes 24b and 24y through first and second via holes 32x and 32y provided in the gate insulating layer 32 and the protective layer 28, respectively. It is connected.

  In this way, as in the first embodiment, the Sw − configured by the source electrodes 24a and 24x, the drain electrodes 24b and 24y, the gate electrodes 30a and 30b, the gate insulating layer 32, and the organic active layers 36a and 36b, respectively. TFT 5 and Dr-TFT 6 are formed.

  Further, a first organic insulating layer pattern 27 having an opening 27 x provided on the pixel electrode 26 is formed above the Sw-TFT 5 and the Dr-TFT 6. The first organic insulating layer pattern 27 is formed in a forward tapered shape with a taper angle of 60 ° or less, and the surface thereof is water repellent.

  Further, a hole transport layer 38 and a light emitting layer 42 are formed on the pixel electrode 26 in the opening 27 x of the first organic insulating layer pattern 27. As in FIG. 6 of the first embodiment, the plurality of pixel electrodes 26 are defined by a red (R) pixel portion, a green (G) pixel portion, and a blue (B) pixel portion, and correspond to the pixel portions of each color. Thus, a red light emitting layer, a green light emitting layer, and a blue light emitting layer (not shown) are formed. The hole transport layer 38 and the light emitting layer 42 constitute the organic EL layer 3a. The organic EL layer 3a is accurately formed in each pixel portion of the three primary colors in a state defined by the first organic insulating layer pattern 27 that functions as a partition when formed by the ink jet method.

  A metal electrode 46 is formed on the organic EL layer 3a, and the pixel electrode 26, the organic EL layer 3a, and the metal electrode 46 constitute the organic EL element 2a. Further, a sealing layer 48 that covers the organic EL element 2a is formed.

  The flexible organic EL display 1b of the third embodiment has such a configuration, and similarly to the first embodiment, light of a predetermined color is emitted from the light emitting layer 42 of each color to the outside to obtain a color image ( The direction of the arrow in FIG.

  In the third embodiment, similarly to the first embodiment, a photolithography patterning process (source electrodes 24a and 24x, drain electrodes 24b and 24y, pixel electrodes 26, which adversely affect the organic active layers 36a and 36b and the organic EL layer 3a). The step of forming the gate electrodes 30a and 30b and the via holes 32x and 32y) is performed on the glass substrate 20 before the organic active layers 36a and 36b and the organic EL layer 3a are formed. Further, after the organic active layers 36a and 36b connected to the source electrodes 24a and 24x and the drain electrodes 24b and 24y are formed on the glass substrate 20 by the ink jet method, a barrier insulating layer 37 is formed to cover the organic active layers 36a and 36b. A layer is obtained. Thereafter, the organic EL layer 3a is formed on the pixel electrode 26 by an ink jet method after the transfer layer is transferred onto the plastic film 40 while being inverted upside down. Therefore, as in the first embodiment, there is no possibility that the organic active layers 36a and 36b and the organic EL layer 3a are deteriorated by various processes in the photolithography process.

  As described above, in the third embodiment, similarly to the first embodiment, a flexible organic EL display including an organic TFT using a plastic film as a substrate can be stably manufactured with a high yield.

(Fourth embodiment)
15-17 is sectional drawing which shows the manufacturing method of the flexible display of 4th Embodiment of this invention, FIG. 18 is sectional drawing which shows the flexible display of 4th Embodiment of this invention.

  The fourth embodiment differs from the first embodiment in that the TFT structure is different. 15 to 18, the same elements as those of the first embodiment are denoted by the same reference numerals, and detailed description of materials and forming methods thereof is omitted.

  As shown in FIG. 15A, the flexible display manufacturing method according to the fourth embodiment of the present invention firstly forms the release layer 22 on the glass substrate 20 by the same method as in the first embodiment. Then, a gate electrode 30a for Sw-TFT and a gate electrode 30b for Dr-TFT are formed. Thereafter, as shown in FIG. 15B, a gate insulating layer 32 covering the upper and side surfaces of the gate electrodes 30a and 30b is formed.

  Subsequently, as shown in FIG. 15C, the Sw-TFT source electrode 24a and drain electrode 24b, and the Dr-TFT source electrode 24x and drain electrode 24y are connected to both end portions on each gate insulating layer 32. Each is formed to extend from the side to the side. Further, the pixel electrode 26 electrically connected to the drain electrode 24y for the Dr-TFT is formed on the peeling layer 22.

  Next, as shown in FIG. 15D, the Sw-TFT organic active layer 36a electrically connected to the Sw-TFT source electrode 24a and the drain electrode 24b is formed on the source electrode 24a and the drain electrode 24b. To form. At the same time, an organic active layer 36b for Dr-TFT electrically connected to the source electrode 24x and drain electrode 24y for Dr-TFT is formed on the source electrode 24x and drain electrode 24y. As in the first embodiment, since the organic active layers 36a and 36b are formed by mask vapor deposition, there is no possibility that the performance of the organic active layers 36a and 36b is deteriorated by wet processing or plasma in the photolithography process.

  Thus, the Sw-TFT 5 including the gate electrode 30a, the gate insulating layer 32, the source electrode 24a, the drain electrode 24b, and the organic active layer 36a connected to the source electrode 24a and the drain electrode 24b is obtained. In addition, the Dr-TFT 6 including the gate electrode 30b, the gate insulating layer 32, the source electrode 24x, the drain electrode 24y, and the organic active layer 36b connected to the source electrode 24x and the drain electrode 24y is obtained.

  Next, as shown in FIGS. 16A and 16B, a protective layer 28 is formed on the Sw-TFT 5 and the Dr-TFT 6, and these steps are buried and planarized, and then the protective layer 28 is formed on the protective layer 28. A barrier insulating layer 37 is formed.

  Thereafter, as shown in FIG. 16C, the plastic film 40 is bonded to the upper surface of the barrier insulating layer 37 of FIG. Subsequently, as shown in FIG. 16C, a roll 29 is fixed to one end of the plastic film 40, and the glass substrate 20 is peeled off while the roll 29 is rotated. At this time, it peels along the interface (A part of FIG.16 (c)) of the glass substrate 20 and the peeling layer 22, and the glass substrate 20 is discarded.

  Thereby, as shown in FIG. 17A, the adhesive layer 34, the barrier insulating layer 37, the protective layer 28, the organic active layers 36a and 36b, and the source electrodes 24a and 24x are formed on the plastic film 40 in order from the bottom. The drain electrodes 24b and 24y, the gate insulating layer 32, the gate electrodes 30a and 30b, the pixel electrode 26 connected to the drain electrode 24y of the Dr-TFT 6, and the peeling layer 22 are transferred and formed in an inverted state.

  Thereafter, as shown in FIG. 17B, the release layer 22 is removed, and the upper surfaces of the gate electrodes 30a and 30b and the pixel electrode 26 are exposed.

  Also in the fourth embodiment, a method is employed in which the TFTs 5 and 6 are formed on the glass substrate 20 with the organic active layers 36a and 36b on the upper side, and then transferred and formed on the plastic film 40 in an inverted state. is doing. Accordingly, since the organic active layers 36a and 36b are not exposed on the upper side of the plastic film 40 but are embedded in the lower side, the organic active layers 36a and 36b may be damaged in various processing steps thereafter. Disappears.

  Subsequently, as shown in FIG. 17C, a hole transport layer 38, a light emitting layer 42, an electron transport layer 44, and a metal electrode 46 are sequentially formed on the pixel electrode 26 by mask vapor deposition. Thereby, the organic EL layer 3 constituted by the hole transport layer 38, the light emitting layer 42 and the electron transport layer 44 is obtained, and the organic EL element 2 constituted by the pixel electrode 26, the organic EL layer 3 and the metal electrode 46. Is obtained.

  Thus, in this embodiment, since the process of forming the organic active layers 36a and 36b and the organic EL layer 3 and the subsequent processes do not use photolithography, the organic active layers 36a and 36b and the organic EL layer 3 can be There is no possibility that the performance is deteriorated by various processes in the lithography process.

  Thereafter, as shown in FIG. 18, a sealing layer 48 that covers the organic EL element 2, the Sw-TFT 5, and the Dr-TFT 6 is formed. Thus, the flexible organic EL display 1c according to the fourth embodiment of the present invention is completed.

  As shown in FIG. 18, in the flexible display 1 c of the fourth embodiment, an adhesive layer 34, a barrier insulating layer 37, and a protective layer 28 are sequentially formed on a plastic film 40. In the protective layer 28, the Sw-TFT 5 and the Dr-TFT 6 are embedded and formed. The Sw-TFT 5 and the Dr-TFT 6 are configured by forming organic active layers 36a and 36b, source electrodes 24a and 24x, drain electrodes 24b and 24y, a gate insulating layer 32, and gate electrodes 30a and 30b in this order from the bottom. ing.

  The source electrodes 24a and 24x and the drain electrodes 24b and 24y are formed to extend upward from between both end sides of the organic active layers 36a and 36b and the gate insulating layer 32, respectively. Further, a pixel electrode 26 electrically connected to the drain electrode 24 y of the Dr-TFT 6 is embedded in the protective layer 28. In this way, the upper surfaces of the gate electrodes 30 a and 30 b and the pixel electrode 26 are flush with the upper surface of the protective layer 28.

  As in the first embodiment, the organic EL layer 3 is formed on the pixel electrode 26, and the metal electrode 46 is formed thereon, so that the organic EL element 2 is configured. Furthermore, the organic EL element 2 is sealed with a sealing layer 48.

  Also in the fourth embodiment, it is possible to make full color using the light emitting layers of the three primary colors as in the first embodiment, or use a white light emitting layer as in the second embodiment and combine the color filters. Full color may be used.

  Moreover, you may form an organic active layer and an organic electroluminescent layer by the inkjet method or printing like 3rd Embodiment. In the case where the organic active layers 36a and 36b are formed by the inkjet method, before forming the organic active layers 36a and 36b as in the third embodiment, an organic insulating layer in which openings are formed is formed. What is necessary is just to form. Further, when the organic EL layer 3 is formed by the ink jet method, the region where the pixel electrode is formed after the release layer 22 is formed (before the gate electrodes 30a and 30b are formed) as in the third embodiment. An organic insulating layer is formed after forming a mask metal layer having an opening in the substrate, and after the transfer onto the plastic film, the organic insulating layer may be patterned using the mask metal layer as a mask.

  In the fourth embodiment, the structure of the TFTs 5 and 6 is different from that in the first embodiment, but the same effects as in the first embodiment are obtained.

(Fifth embodiment)
19 to 22 are cross-sectional views sequentially illustrating a method for manufacturing a flexible display according to a fifth embodiment of the present invention, and FIG. 23 is a cross-sectional view illustrating a flexible display (liquid crystal display) according to the fifth embodiment of the present invention. In the fifth embodiment, a mode in which the present invention is applied to a liquid crystal display is illustrated. In the fifth embodiment, detailed description of the same steps as those in the first embodiment is omitted. Moreover, the same code | symbol is attached | subjected to the same element and the description is abbreviate | omitted.

  As shown in FIG. 19A, the flexible display manufacturing method according to the fifth embodiment of the present invention first forms a release layer 22 on a glass substrate 20 as a temporary substrate, and then a source for a switching TFT. An electrode 24 a and a drain electrode 24 b are formed on the peeling layer 22. Subsequently, a pixel electrode 26 made of ITO or the like electrically connected to the drain electrode 24 b is formed on the peeling layer 22.

  Next, as shown in FIG. 19B, a protective layer 28 covering the source electrode 24a, the drain electrode 24b, and the pixel electrode 26 is formed. Thereafter, as shown in FIG. 19C, a TFT gate electrode similar to that of the first embodiment is formed on the protective layer 28 between the source electrode 24a and the drain electrode 24b so as to overlap the end portions of the source electrode 24a and the drain electrode 24b. 30 is formed. Subsequently, a color filter layer 52 is formed on the protective layer 28 corresponding to the pixel electrode 26. In the present embodiment, an example in which the color filter layer 52 is full-colored is illustrated. Although only one pixel portion is shown in FIG. 19C, the pixel electrodes 26 of the three primary color pixel portions (R), (G), and (B) as shown in FIG. 6 of the first embodiment. A red (R) color filter layer, a green (G) color filter layer, and a blue (B) color filter layer are formed thereon. A pixel portion (sub-pixel) of three primary colors constitutes a pixel as a display unit. Each of the three primary color filter layers 52 is formed by sequentially patterning, for example, a pigment dispersion type photosensitive coating film by photolithography.

Subsequently, as shown in FIG. 19D, a gate insulating layer 32 covering the gate electrode 30 and the color filter layer 52 is formed. Next, as shown in FIG. 20A, a via hole 32x is formed in the protective layer 28 and the gate insulating layer 32 on the source electrode 24a and the drain electrode 24b. Further, as shown in FIG. 20B, as in the first embodiment, the organic active layer 36 connected to the source electrode 24a and the drain electrode 24b through the via hole 32x is formed by mask deposition. As in the second embodiment, an organic insulating layer pattern in which an opening is provided may be formed, and the organic active layer 36 may be formed in the opening by an inkjet method.
As a result, the switching TFT 7 including the gate electrode 30, the gate insulating layer 28, the source electrode 24a, the drain electrode 24b, and the organic active layer 36 is obtained. Thereafter, as shown in FIG. 20C, a barrier insulating layer 37 covering the organic active layer 36 is formed.

  Next, as shown in FIG. 21A, after the first plastic film 40 is bonded to the barrier insulating layer 37 of FIG. 20C via the adhesive layer 34, one end of the first plastic film 40 is formed. The glass substrate 20 is peeled off while rotating the roll 29 fixed to. At this time, it peels along the interface (A part of Fig.21 (a)) of the glass substrate 20 and the peeling layer 22, and the glass substrate 20 is discarded.

  Thus, as shown in FIG. 21B, the adhesive layer 34, the barrier insulating layer 37, the organic active layer 36, the gate insulating layer 32, the gate electrode 30 and the color are formed on the first plastic film 40 in order from the bottom. The filter layer 52, the protective layer 28, the source electrode 24a, the drain electrode 24b, the pixel electrode 26, and the peeling layer 22 are transferred and formed.

  Next, as shown in FIG. 21C, the release layer 22 is removed, so that the upper surfaces of the source electrode 24a, the drain electrode 24b, and the pixel electrode 26 are exposed.

  Thereafter, as shown in FIG. 22, an alignment film 54a for aligning liquid crystal is formed on the source electrode 24a, the drain electrode 24b, and the pixel electrode 26. Thereby, the TFT substrate 8 for flexible liquid crystal displays is obtained.

  As shown in FIG. 22, in the TFT substrate 8 for a flexible liquid crystal display, a first plastic film 40 is used as a substrate, and an adhesive layer 34 and a barrier insulating layer 37 are sequentially formed thereon. On the barrier insulating layer 37, an organic active layer 33 for TFT and a gate insulating layer 32 are sequentially formed. Further, a gate electrode 30 for TFT and a color filter layer 52 are formed on the gate insulating layer 32, and a protective layer 28 is formed thereon. Further, the pixel electrode 26 connected to the TFT source electrode 24a, drain electrode 24b, and drain electrode 24b is formed on the protective layer 20, and an alignment film 54a is provided thereon.

  Next, as shown in FIG. 23, a counter substrate 9 of the TFT substrate 8 is prepared. The counter substrate 9 is basically composed of a second plastic film 40a, a common electrode 58 made of ITO or the like formed thereon, and an alignment film 54b formed thereon. Then, the TFT substrate 8 and the counter substrate 9 are bonded to each other with a sealant (not shown) provided at the periphery in a state where a predetermined interval is secured by the spacer, and the TFT substrate 8 and the counter substrate 9 are further bonded. Liquid crystal 70 is sealed in the gap.

  As described above, the flexible liquid crystal display 1d of the fifth embodiment is completed.

  In addition, you may use the TFT substrate provided with TFT obtained by the manufacturing method of 4th Embodiment mentioned above. Further, the color filter layer 52 may be formed at any stage after the pixel electrode 26 is formed and before the organic active layer 36 is formed. Therefore, the color filter layer 52 may be provided between the gate insulating layer 32 and the barrier insulating layer 37. Alternatively, the color filter layer 52 may be provided on the counter substrate 9.

  Although not particularly illustrated, a data bus line is connected to the source electrode 24 a of the TFT 7, and a gate bus line is connected to the gate electrode 30 of the TFT 7. Then, gradation voltages are sequentially applied from the gate bus line and the data bus line to the pixel electrode 26 of each pixel via the TFT 7 at a predetermined timing, and an image is displayed.

  In the fifth embodiment, as in the first embodiment, since it is not necessary to perform a photolithography process after forming the organic active layer 36, the performance of the organic active layer 36 is degraded by various processes in the photolithography process. The risk of doing so is eliminated.

  Moreover, the main part of the organic active layer 36 is embedded and provided on the plastic film 40 side relatively away from the liquid crystal 70 through the source electrode 24a, the drain electrode 24b, the protective layer 28, the gate electrode 30 and the gate insulating layer 32. Therefore, characteristic deterioration due to the influence from the liquid crystal 70 can be prevented. Furthermore, since the barrier insulating layer 37 is formed under the organic active layer 36 (on the plastic film side), water vapor from outside air and moisture in the plastic film 40 enter the organic active layer 36 and the liquid crystal 70. Is prevented. Thereby, the performance degradation of the organic active layer 36 and the liquid crystal 70 is prevented, and the reliability of the flexible liquid crystal display including the organic TFT can be improved.

  As described above, in the fifth embodiment, an active matrix type flexible liquid crystal display using an element substrate in which an organic TFT is formed on a plastic film can be stably manufactured at a high yield.

  The present invention can also be applied to a flexible type electrophoretic display in addition to a flexible type organic EL display and a liquid crystal display.

1A to 1D are cross-sectional views (part 1) showing the method for manufacturing the flexible display according to the first embodiment of the present invention. 2A to 2C are cross-sectional views (part 2) illustrating the method for manufacturing the flexible display according to the first embodiment of the present invention. 3A to 3C are cross-sectional views (part 3) illustrating the method for manufacturing the flexible display according to the first embodiment of the present invention. 4A to 4D are cross-sectional views (part 4) illustrating the method for manufacturing the flexible display according to the first embodiment of the present invention. FIG. 5: is sectional drawing (the 5) which shows the manufacturing method of the flexible display of 1st Embodiment of this invention. FIG. 6 is a cross-sectional view showing the flexible display (organic EL display) of the first embodiment of the present invention. FIG. 7 is a diagram showing an equivalent circuit of one pixel portion of the flexible display according to the first embodiment of the present invention. FIG. 8 is a plan view of one pixel portion of the flexible display according to the first embodiment of the present invention as seen from the plane direction. FIG. 9 is a sectional view showing a flexible display (organic EL display) according to the second embodiment of the present invention. 10A to 10C are cross-sectional views (part 1) showing the method for manufacturing the flexible display according to the third embodiment of the present invention. 11A to 11C are cross-sectional views (part 2) showing the method for manufacturing the flexible display according to the third embodiment of the present invention. 12A to 12C are cross-sectional views (part 3) showing the method for manufacturing the flexible display according to the third embodiment of the present invention. FIGS. 13A to 13C are cross-sectional views (part 4) showing the method for manufacturing the flexible display according to the third embodiment of the present invention. FIG. 14 is a cross-sectional view showing a flexible display (organic EL display) according to a third embodiment of the present invention. FIGS. 15A to 15D are sectional views (No. 1) showing the method for manufacturing the flexible display according to the fourth embodiment of the present invention. 16A to 16C are cross-sectional views (part 2) illustrating the method for manufacturing the flexible display according to the fourth embodiment of the present invention. 17A to 17C are cross-sectional views (part 3) illustrating the method for manufacturing the flexible display according to the fourth embodiment of the present invention. FIG. 18 is a sectional view showing a flexible display according to the fourth embodiment of the present invention. FIGS. 19A to 19D are sectional views (No. 1) showing the method for manufacturing the flexible display according to the fifth embodiment of the present invention. 20A to 20C are cross-sectional views (part 2) illustrating the method for manufacturing the flexible display according to the fifth embodiment of the present invention. 21A to 21C are cross-sectional views (part 3) illustrating the method for manufacturing the flexible display according to the fifth embodiment of the present invention. FIG. 22: is sectional drawing which shows the manufacturing method of the flexible display of 5th Embodiment of this invention (the 4). FIG. 23 is a sectional view showing a flexible display (liquid crystal display) according to a fifth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b, 1c ... Flexible organic EL display, 1d ... Flexible liquid crystal display, 2, 2a ... Organic EL element, 3, 3a ... Organic EL layer, 5 ... Sw-TFT, 6 ... Dr-TFT, 7 ... TFT, 8 ... TFT substrate, 9 ... Counter substrate, 20 ... Glass substrate, 22 ... Peeling layer, 24a, 24x ... Source electrode, 24b, 24y ... Drain electrode, 25 ... Mask metal layer, 25x, 27x, 39x ... Opening, 26 ... Pixel electrode, 27a ... first organic insulating layer, 27 ... first organic insulating layer pattern, 32 ... gate insulating layer, 29 ... roll, 30a, 30b ... gate electrode, 31 ... nozzle, 32 ... protective layer, 33,35 ... Coating liquid, 34 ... adhesive layer, 36a, 36b ... organic active layer, 37 ... barrier insulating layer, 38 ... hole transport layer, 39 ... second organic insulating layer pattern, 40, 40a ... plasty 42: Light emitting layer, 42G: Green light emitting layer, 42B ... Blue light emitting layer, 44 ... Electron transport layer, 46 ... Metal electrode, 48 ... Sealing layer, 52, 52R, 52G, 52B ... color filter layer, 54a, 54b ... alignment film, 58 ... common electrode, 70 ... liquid crystal.

Claims (21)

An active matrix type flexible display in which a TFT is provided for each pixel,
Plastic film,
An adhesive layer formed on the plastic film;
A barrier insulating layer formed on the adhesive layer;
A TFT having a structure in which an organic active layer, a gate insulating layer, and a gate electrode are formed in order from the bottom, and a source electrode and a drain electrode are electrically connected to the organic active layer. When,
A pixel electrode formed above the barrier insulating layer and electrically connected to the drain electrode of the TFT;
An organic EL layer including a light emitting layer formed on the pixel electrode of each pixel;
A metal electrode formed on the organic EL layer;
A flexible display comprising a sealing layer covering the metal electrode. A protective layer is formed on the gate electrode, and the source electrode, the drain electrode, and the pixel electrode of the TFT are embedded in the protective layer,
The organic active layer is electrically connected to the source electrode and the drain electrode through via holes provided in necessary portions of the gate insulating layer and the protective layer on the organic active layer. The flexible display according to claim 1. The source electrode and the drain electrode of the TFT are formed to extend upward from between the organic active layer and the gate insulating layer,
The flexible display according to claim 1, wherein a protective layer is formed on the barrier insulating layer, and the TFT and the pixel electrode are embedded in the protective layer.   The pixel is defined by a red pixel portion, a green pixel portion, and a blue pixel portion, and the light emitting layer is formed in a red (R) light emitting layer formed in the red pixel portion and the green pixel portion. 4. The flexible display according to claim 1, comprising a green (G) light-emitting layer and a blue (B) light-emitting layer formed in the blue pixel portion. 5.   The flexible display according to claim 1, wherein the light emitting layer is a white light emitting layer and further includes a color filter layer.   The flexible display according to claim 2, wherein each upper surface of the source electrode, the drain electrode, and the pixel electrode is flush with an upper surface of the protective layer.   The flexible display according to claim 2, wherein an upper surface of the gate electrode is flush with an upper surface of the gate insulating layer.   The organic insulating layer further includes an organic insulating layer pattern formed between the barrier insulating layer and the gate insulating layer and having an opening provided in a region including the via hole and the gate electrode. The flexible display according to claim 2, wherein the flexible display is formed over an opening of the organic insulating layer pattern. Further comprising an organic insulating layer pattern provided with openings on the pixel electrodes,
The flexible display according to any one of claims 1 to 3, wherein the organic EL layer is formed in the opening on the pixel electrode of the organic insulating layer pattern.   The flexible display according to claim 3, wherein each upper surface of the gate electrode and the pixel electrode is flush with an upper surface of the protective layer.   2. The TFT according to claim 1, wherein the TFT includes a switching TFT and a driving TFT connected to the switching TFT, and the drain electrode of the driving TFT is connected to the pixel electrode. The flexible display as described in any one of thru | or 3. The organic EL layer is
The light emitting layer;
It is constituted by at least one of a hole transport layer formed between the pixel electrode and the light emitting layer and an electron transport layer formed between the light emitting layer and the metal electrode. The flexible display according to any one of claims 1 to 3. An active matrix type flexible display in which a TFT is provided for each pixel,
A first plastic film, an adhesive layer formed on the first plastic film, and formed on or above the barrier insulating layer, and an organic active layer, a gate insulating layer, and a gate electrode are sequentially formed from the bottom. A TFT having a structure in which a source electrode and a drain electrode are electrically connected to the organic active layer, and a pixel electrode formed above the barrier insulating layer and electrically connected to the drain electrode of the TFT And a TFT substrate comprising a first alignment film formed on the TFT and the pixel electrode,
A counter substrate comprising a second plastic film, a common electrode formed on the second plastic film, and a second alignment film formed on the common electrode;
A flexible display comprising: a liquid crystal sealed between the TFT substrate and the counter substrate.   The flexible display according to claim 13, wherein a color filter layer is further provided on the TFT substrate. An active matrix flexible display manufacturing method in which a TFT is provided for each pixel,
Forming a release layer on the temporary substrate;
A TFT having a structure in which a gate electrode, a gate insulating layer, and an organic active layer are formed in order from the bottom on the release layer, and a source electrode and a drain electrode are electrically connected to the organic active layer; Forming a pixel electrode electrically connected to the drain electrode;
Forming a barrier insulating layer on or above the TFT;
Adhering a plastic film on the barrier insulating layer via an adhesive layer;
A state where the barrier insulating layer, the TFT, the pixel electrode, and the release layer are turned upside down on the plastic film through the adhesive layer by peeling the temporary substrate from the interface with the release layer. The process of transferring and forming with
Removing the release layer to expose part of the TFT and the pixel electrode;
Forming an organic EL layer including a light emitting layer on the pixel electrode of each pixel;
Forming a metal electrode on the organic EL layer;
And a step of forming a sealing layer covering the metal electrode. The step of forming the TFT and the pixel electrode includes:
Forming a source electrode and a drain electrode on the release layer, and forming a pixel electrode electrically connected to the drain electrode;
Forming a protective layer covering the source electrode, the drain electrode, and the pixel electrode;
Forming a gate electrode in a portion on the protective layer between the source electrode and the drain electrode;
Forming a gate insulating layer covering the gate electrode;
Forming via holes each having a depth reaching the source electrode and the drain electrode in the gate insulating layer and the protective layer;
And forming an organic active layer electrically connected to the source electrode and the drain electrode through the via hole on the gate insulating layer. Production method. The step of forming the TFT and the pixel electrode includes:
Forming a gate electrode on the release layer;
Forming a gate insulating layer covering the top and side surfaces of the gate electrode;
Forming a source electrode and a drain electrode on both ends of the gate insulating layer, and forming a pixel electrode connected to the drain electrode on the release layer;
The method of manufacturing a flexible display according to claim 15, further comprising: forming an organic active layer on the gate insulating layer, the source electrode, and the drain electrode.   The method for manufacturing a flexible display according to claim 15, wherein the organic active layer and the organic EL layer are formed by mask vapor deposition. After the step of forming the via hole, the method further includes the step of forming an organic insulating layer pattern in which an opening is provided in a region including the via hole and the gate electrode on the gate insulating layer,
17. The flexible display according to claim 16, wherein in the step of forming the organic active layer, the organic active layer is formed in the via hole and in the opening of the organic insulating layer pattern by an inkjet method or printing. Method. Before the step of forming the pixel electrode,
Patterning a mask layer on the release layer;
Further comprising forming an organic insulating layer on the release layer and the mask layer,
In the step of removing the release layer, after the release layer is removed, the organic insulating layer is etched using the mask layer as a mask, and the mask layer is further removed so that an opening is formed on the pixel electrode. Forming a provided organic insulating layer pattern;
18. The step of forming the organic EL layer, wherein the organic EL layer is formed in the opening on the pixel electrode of the organic insulating layer pattern by an ink-jet method or printing. The manufacturing method of the flexible display of claim | item. An active matrix flexible display manufacturing method in which a TFT is provided for each pixel,
Forming a release layer on the temporary substrate;
A TFT having a structure in which a gate electrode, a gate insulating layer, and an organic active layer are formed in order from the bottom on the release layer, and a source electrode and a drain electrode are electrically connected to the organic active layer; Forming a pixel electrode electrically connected to the drain electrode;
Forming a barrier insulating layer on or above the TFT;
Adhering a plastic film on the barrier insulating layer via an adhesive layer;
A state where the barrier insulating layer, the TFT, the pixel electrode, and the release layer are turned upside down on the plastic film through the adhesive layer by peeling the temporary substrate from the interface with the release layer. The process of transferring and forming with
Removing the release layer to expose part of the TFT and the pixel electrode;
Forming a TFT substrate by a manufacturing method including a step of forming an alignment film on the TFT and the pixel electrode;
The TFT substrate and a counter substrate having a structure in which a common electrode and an alignment film are formed on the second plastic film are bonded to each other with a predetermined interval, and liquid crystal is sealed between the TFT substrate and the counter substrate. A method for manufacturing a flexible display.

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