JP2016197494A - Organic EL display device - Google Patents

Abstract

Kind Code: A1 An organic EL display device capable of efficiently patterning an organic film including a light-emitting layer by laser ablation is provided. An organic film including a light-emitting layer and a second region R2 adjacent to the edge of the first region, other than the first region R1 provided with the organic film in plan view, are provided in the first region. and a reflective film 1135 formed along the edge for reflecting a laser beam of a predetermined wavelength. [Selection drawing] Fig. 3A

Description

  The present invention relates to an organic EL display device.

  It is known that an organic film including a light emitting layer in an organic EL display device is formed by patterning into a predetermined shape by using a mask in an etching or photolithography process, as disclosed in Patent Document 1 below. It has been.

JP 2006-302860 A

  However, the formation of the organic film using the mask as described above requires regular maintenance of dedicated equipment and the mask. And the equipment cost and operation cost increase as the substrate becomes large. For this reason, the inventors diligently studied a manufacturing method that can form an organic film more easily than a conventional forming method.

  The inventors then considered whether laser ablation, which is a processing technique using a laser beam, could be applied to the formation of an organic film. This method is a method of removing an unnecessary organic film portion by irradiating a laser beam and patterning the organic film into a predetermined shape.

  If this method is realized, it is possible to form an organic film without a mask, so that it is not necessary to reduce operation costs or to introduce dedicated equipment, so that a reduction in manufacturing cost can be expected.

  However, since the organic film including the light emitting layer provided in the organic EL display device usually has little light absorption, it takes time to remove the unnecessary organic film portion, and shortens the time to remove the unnecessary organic film portion. In order to achieve this, it has been found that there is a problem that it is necessary to irradiate a laser beam at a high output.

  In order to solve this problem, the inventors have made further intensive studies on applying a new film structure to an organic EL display device for realizing removal of an unnecessary organic film portion by laser ablation. .

  An object of the present invention is to provide an organic EL display device capable of efficiently patterning an organic film including a light emitting layer by laser ablation.

  The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

  One aspect of the organic EL display device according to the present invention is an organic film including a light emitting layer and a region other than the first region where the organic film is provided in a plan view and adjacent to an edge of the first region. The two regions include a reflection film that is formed along the edge of the first region and reflects a laser beam having a predetermined wavelength.

1 is a perspective view schematically showing an organic EL display device according to an embodiment of the present invention. It is a figure which shows the cross section in the cutting line II-II of FIG. It is a top view explaining the manufacturing method of the organic electroluminescence display which concerns on embodiment of this invention. It is a figure which shows the cross section in the cutting line IIIB-IIIB of FIG. 3A. It is a top view explaining the manufacturing method of the organic electroluminescence display which concerns on embodiment of this invention. It is a figure which shows the cross section in the cutting | disconnection line IVB-IVB of FIG. 4A. It is a top view explaining the manufacturing method of the organic electroluminescence display which concerns on embodiment of this invention. It is a figure which shows the cross section in the cutting plane line VB-VB of FIG. 5A.

  First, an outline of the organic EL display device according to the present embodiment will be described with reference to FIGS.

  FIG. 1 is a perspective view schematically showing an organic EL display device according to an embodiment of the present invention. FIG. 2 is a view showing a cross section taken along the section line II-II in FIG.

  The organic EL display device 10 according to the present embodiment includes, for example, a circuit board 11. The circuit board 11 is mounted with an integrated circuit chip 12 for driving an element for displaying an image.

  A flexible wiring board 13 is connected to the circuit board 11 for electrical connection with the outside. As shown in FIG. 2, the circuit board 11 includes a first substrate 111 made of glass or the like, a circuit layer 112, and the like. The circuit layer 112 includes a thin film transistor (TFT) 1121 including a wiring, an electrode, an insulating film, and the like.

  As shown in FIGS. 1 and 2, the circuit board 11 includes an element layer 113. The element layer 113 includes an organic film 1131 (also referred to as an organic electroluminescence film). The organic film 1131 includes at least a light emitting layer (not shown), and may further include at least one of an electron transport layer, a hole transport layer, an electron injection layer, and a hole injection layer.

  The light emitting layer included in the organic film 1131 shown in FIGS. 1 and 2 may emit only light of one color (for example, white). In this case, the organic EL display device 10 emits various colors to the outside through the color filter 141 (141R, 141G, 141B) of any color of RGB provided on the counter substrate 14 with the light emitted from the light emitting layer. It will be visually recognized.

  Further, the light emitting layer may be configured to emit light of a plurality of colors different for each pixel. In this case, the color filter 141 of the counter substrate 14 shown in FIGS. The counter substrate 14 will be described in detail later.

  The element layer 113 includes an anode 1132 (also referred to as an anode or a pixel electrode) and a cathode 1133 (also referred to as a cathode or a common electrode). The anode 1132 and the cathode 1133 are electrically connected to the circuit layer 112, respectively.

  In the example of FIGS. 1 and 2, a plurality of anodes 1132 are formed above the circuit layer 112. The plurality of anodes 1132 are provided corresponding to the plurality of pixels. An organic film 1131 is continuously provided on the plurality of anodes 1132. A cathode 1133 is continuously provided on the organic film 1131.

  As described above, the element layer 113 includes the anode 1132 and the cathode 1133 that sandwich the organic film 1131. By applying a voltage to the anode 1132 and the cathode 1133, holes and electrons are injected into the organic film 1131 from each of them, and light is emitted by combining the injected holes and electrons in the light emitting layer included in the organic film 1131.

  Here, the organic material forming the organic film 1131 may have a characteristic of absorbing moisture from the outside and easily holding the moisture. Such moisture entering from the outside may adversely affect the organic film 1131, particularly the light emitting layer, and is not preferable.

  Therefore, in order to prevent a display defect caused by diffusion of moisture from the outside to the display area DA of the organic EL display device 10 in the organic film 1131, a part of the organic film 1131 is divided to remove moisture from the outside. A moisture blocking structure MB is provided to block the water.

  Further, the surface of the circuit layer 112 opposite to the side facing the first substrate 111 has unevenness due to the thin film transistor 1121 including wiring, electrodes, an insulating film, and the like.

  The unevenness can cause the organic film 1131 to break when an organic film 1131 including an electrode and a light emitting layer is laminated on the upper side. The disconnection of the organic film 1131 is not preferable because it may cause a short circuit between the anode 1132 and the cathode 1133.

  Therefore, as shown in FIG. 2, the organic EL display device 10 according to this embodiment may include an organic flattening film 1134 for flattening the aforementioned unevenness on the surface of the circuit layer 112.

  In order to flatten the unevenness of the circuit layer 112, the organic flattening film 1134 needs to have a certain thickness. As the organic planarization film 1134 formed using an organic material, a film having a film thickness that can easily flatten the unevenness can be formed as compared with a film formed using an inorganic material.

  The organic planarization film 1134 can be formed using an organic resin such as an acrylic resin, for example. Here, in the case where the organic planarizing film 1134 is formed of an organic resin, the organic resin may absorb moisture from the outside and have a characteristic of easily holding the moisture.

  As described above, moisture entering from the outside may adversely affect the element layer 113, particularly the organic film 1131 including the light emitting layer, and is not preferable.

  Therefore, in order to prevent a display defect caused by diffusion of moisture from the outside to the display area DA of the organic EL display device 10 as in the organic film 1131, a part of the organic flattening film 1134 is added to the organic flattening film 1134. It is good also as providing the water | moisture-content blocking | blocking structure MB which cuts off and interrupts | blocks the moisture from the outside.

  Here, the end portion of the organic planarization film 1134 forming the moisture blocking structure MB may be provided with a tapered portion 1134b having a tapered shape as shown in FIG.

  As shown in FIG. 2, a through hole 1134 c for electrically connecting the anode 1132 and the cathode 1133 of the element layer 113 and the circuit layer 112 is formed in a part of the organic planarizing film 1134. It is good to be.

  A structure in which the cathode 1133 and the circuit layer 112 are electrically connected through the through hole 1134c formed in the organic planarizing film 1134 is referred to as a cathode contact CC in this specification.

  Further, in the organic EL display device 10 according to the present embodiment, a reflective film 1135 is provided between the anode 1132 and the organic planarizing film 1134 in order to increase the extraction efficiency of light emitted from the light emitting layer. It is good as well.

  In this case, the anode 1132 is formed of a metal that transmits visible light, such as ITO. The reflective film 1135 provided between the anode 1132 and the organic planarizing film 1134 may be anything that reflects visible light, for example. For example, it may be formed of a metal such as Al, or a three-layer structure (Ti / Al / Ti) of aluminum and titanium.

  The organic EL display device 10 according to the present embodiment is a region other than the first region R1 provided with the organic film 1131 in a plan view, and also in the second region R2 adjacent to the edge of the first region R1. A reflective film 1135 is provided. The reflective film 1135 in the second region R2 is formed along the edge of the first region R1. The reflection film 1135 formed along the edge of the first region R1 reflects a laser beam having a predetermined wavelength. The first region R1 and the second region R2 correspond to regions R1 and R2 shown in FIGS. 4A and 5A described later.

  Further, it is formed in the second region R2 other than the first region R1 provided with the organic film 1131 in plan view and adjacent to the edge of the first region R1 along the edge of the first region R1. The reflective film is provided in a region where the organic film 1131 is not provided in a plan view, that is, is provided surrounding the display region in a plan view.

  Hereinafter, the reflective film 1135 that reflects visible light is referred to as the first reflective film 1135a and the reflective film that reflects a laser beam having a predetermined wavelength is referred to as the second reflective film 1135b.

  Here, the second reflective film 1135b may be formed of the same material as the first reflective film 1135a. In this case, the reflective film in the second region R2 and the reflective film in the first region R1 may be formed in the same process and formed in the same layer.

  The second reflective film 1135b may be formed of a material different from that of the first reflective film 1135a. For example, the second reflective film 1135b may be formed of, for example, a three-layer structure of Ag, Ni, Ti, or Ti / Al / Ti.

  Further, a reflection film (second reflection film 1135b) that reflects a laser beam having a predetermined wavelength is formed on the inner surface of the through hole 1134c in the cathode contact CC formed to be electrically connected to the cathode 1133. Also good.

  Similarly, the tapered portion 1134b provided at the end of the organic planarizing film 1134 forming the moisture blocking structure MB similarly reflects a laser beam having a predetermined wavelength along the shape of the tapered portion 1134b (first film). 2 reflection film 1135b) may be formed at least partially.

  Here, the reflectance of the laser beam of the second reflective film 1135b may be 60% or more, for example. Further, the reflectance of the laser beam of the second reflective film 1135b may be, for example, 65% or more, 70% or more, or 75% or more.

  The laser beam having the predetermined wavelength may be a laser beam having a wavelength of 350 nm or more and 550 nm or less. That is, the reflective film may reflect 60% or more of a laser beam having a wavelength of 350 nm or more and 550 nm or less.

  In general, the metal tends to decrease in reflectance as the wavelength of the laser beam becomes shorter. On the other hand, the reflectance of a metal changes with the kind of metal material which comprises a reflecting film. In general, this depends on electrical conductivity, and it is said that the reflectivity increases as the electrical conductivity increases.

  Therefore, the electrical conductivity of the second reflective film 1135b may be larger than the electrical conductivity of the first reflective film 1135a.

  The counter substrate 14 is disposed so as to face the circuit substrate 11. As shown in FIG. 2, the counter substrate 14 is a color filter substrate, and includes a second substrate 142, a black matrix 143 provided on the circuit substrate 11 side of the second substrate 142, and a color filter 141 that is a colored layer. It is good also as including.

  Further, as described above, when the organic film 1131 includes a plurality of light emitting layers that emit different colors (for example, red, green, and blue), a colored layer is unnecessary.

  Next, while explaining the manufacturing method of the organic EL display device 10 according to the present embodiment, the detailed configuration of the organic EL display device 10 according to the present embodiment will be further described.

  The manufacturing method of the organic EL display device according to the present embodiment is a manufacturing method of an organic EL display device in which an organic film including a light emitting layer is provided in a first region in plan view, and the region other than the first region. A step of forming a reflective film for reflecting a laser beam having a predetermined wavelength formed along the edge in a second area adjacent to the edge of the first area; and the first area in plan view; And the step of forming the organic film on the region including the second region so as to partially overlap the reflective film, and irradiating the region including at least the second region with the laser beam, and And a step of removing a part of the organic film formed so as to overlap with the region.

  FIG. 3A is a plan view illustrating the method for manufacturing the organic EL display device 10 according to the embodiment of the present invention. FIG. 3B is a diagram showing a cross section taken along section line IIIB-IIIB in FIG. 3A.

  First, a circuit layer in which wiring, a thin film transistor 1121, and the like are formed is formed over a first substrate 111 which is an insulating substrate such as glass or resin. The step of forming the circuit board 11 may be performed by a known method.

  Note that in the case where the thin film transistor 1121 and the like are formed over the first substrate 111 is smooth, the organic planarization film 1134 formed so as to cover the thin film transistor 1121 and the first substrate 111 is not necessarily provided.

  In the following description, it is assumed that the surface immediately after the thin film transistor 1121 is formed has unevenness, the organic film 1131 due to the unevenness is disconnected, and the anode 1132 and the cathode 1133 due to the disconnection are In order to suppress a short circuit, an organic flattening film 1134 for flattening the unevenness is formed after the formation of the circuit layer.

  The organic planarization film 1134 is formed, for example, by forming the organic planarization film 1134 so as to cover at least the entire surface of the pixel region in plan view, and then forming a region in which the cathode contact CC is formed in plan view. It is good also as performing by removing the area | region where is formed.

  The organic planarizing film 1134 may be formed by applying an organic resin varnish (a liquid material obtained by dissolving an organic resin in a solvent) to the uneven surface and volatilizing the solvent contained in the varnish. . By forming in this way, the varnish flows preferentially into the recesses on the surface of the first substrate 111, and the unevenness on the surface of the first substrate 111 is effectively flattened.

    In the case where the organic planarizing film 1134 is composed of a polyimide resin, a liquid material obtained by dissolving a polyamic acid, which is a polyimide precursor, in a solvent may be applied to the uneven surface, and then imidization may be performed.

  In the case where the organic planarizing film 1134 is formed of a thermosetting organic resin, heat treatment may be promoted by applying a heat treatment after applying an organic resin varnish to the uneven surface. In the case where the organic planarizing film 1134 is formed of a photocurable organic resin, a light irradiation treatment may be performed after applying an organic resin varnish to the uneven surface to promote photocuring.

  Note that the material and forming method of the organic planarizing film 1134 are not limited to the above.

  Further, the organic planarization film 1134 in the present embodiment includes a tapered portion 1134b having a tapered shape at the end portion.

  The reflective film (second reflective film 1135b) that reflects a laser beam having a predetermined wavelength is a region other than the first region R1 where the organic film 1131 is provided in plan view, and is adjacent to the edge of the first region R1. The second region R2 is formed along the edge of the first region R1.

  In the present embodiment, at least a part of the second reflective film 1135b is formed along the shape of the tapered portion 1134b of the organic planarizing film 1134. In addition, in the present embodiment, the second reflective film 1135b is formed on the inner surface of the through hole 1134c formed for electrical connection with the cathode 1133.

  That is, the second reflective film is formed on the inner surface of the through hole 1134c formed for electrical connection with the cathode 1133 and the tapered portion 1134b provided at the end of the organic planarization film 1134 forming the moisture blocking structure MB. 1135b is formed.

  Then, for example, a reflective film (first reflective film 1135a) that reflects visible light and an anode 1132 are formed by patterning. Next, a bank 1136 is provided so as to cover a part of the surface of the organic planarization film 1134 opposite to the side facing the first substrate 111 side, covering the end of the anode 1132.

  When the second reflective film 1135b is formed of a material different from that of the first reflective film 1135a, the first reflective film 1135a and the second reflective film 1135b are formed through different patterning processes. . In the case where the second reflective film 1135b and the first reflective film 1135a are formed of the same material, the first reflective film 1135a and the second reflective film 1135b may be formed through the same patterning process. .

  Thereafter, a bank 1136 is formed in contact with a part of the surface of the organic planarization film 1134 opposite to the first substrate 111 side so as to cover the end portion of the anode 1132.

  Note that the bank 1136 is formed so as to cover the end portion of the anode 1132 and all other surfaces on the upper surface of the organic planarizing film 1134 where the anode 1132 is not formed in the image region in plan view. It is good. The bank 1136 is formed so as to cover the entire other surface of the upper surface of the organic flattening film 1134 where the anode 1132 is not formed because it is simpler in terms of the process and is considered to have no harmful effect on performance. is there.

  In this way, the state of material in process in the manufacturing process is shown in FIGS. 3A and 3B.

  Next, a process of patterning the organic film 1131 including the light emitting layer by laser ablation from the state shown in FIGS. 3A and 3B will be described.

  FIG. 4A is a plan view illustrating the method for manufacturing the organic EL display device according to the embodiment of the invention. FIG. 4B is a view showing a cross section taken along section line IVB-IVB of FIG. 4A.

  First, from the state shown in FIGS. 3A and 3B, an organic film 1131 including a light emitting layer on the uppermost surface is formed on the entire surface.

  Then, a laser beam L having a predetermined wavelength is irradiated on the portion where the organic film 1131 is to be removed (the region where the cathode contact CC is formed and the region where the moisture blocking structure MB is formed in FIG. 4A).

  In general, an organic film 1131 including a light emitting layer provided in an organic EL display device usually has little light absorption. Therefore, removal of the organic film 1131 by laser ablation requires irradiation with a laser beam with high output.

  In contrast, in the present embodiment. Since the second reflection film 1135b that efficiently reflects the laser beam L irradiated to the portion where the organic film 1131 is to be removed is provided, the irradiated laser beam L is reflected by the second reflection film 1135b and again the organic film 1131. Will pass. As a result, the irradiated laser beam can be used efficiently, and laser ablation can be performed by irradiation with a laser configuration at a low output.

  Further, since the second reflective film 1135b is formed along the shape of the tapered portion 1134b of the organic planarizing film 1134, the second reflective film 1135b is displaced from the irradiation direction of the laser beam L (the arrow direction in FIG. 4B). The component of the laser beam L is reflected so as to be focused again on the organic film 1131 side, and the removal efficiency of the organic film 1131 is further enhanced.

  Thus, by providing the 2nd reflective film 1135b, the output of the laser beam L can be reduced, and the influence by irradiation of a laser structure is suppressed with respect to the other part which comprises the organic electroluminescent display apparatus 10. FIG. Therefore, the reliability of the manufactured organic EL display device 10 is improved.

  Further, the irradiation of the laser beam L with a gentle output reduces the scattering of processing waste (also referred to as debris) generated when the organic film 1131 is removed to the surroundings other than the irradiated portion of the laser beam L. If the processing scraps are scattered to the display area, they become particles and dark spots are generated, which may cause display defects.

  In the present embodiment, by providing the second reflective film 1135b, it is possible to reduce scattering of processing waste, thereby reducing display defects due to generation of dark spots in the manufactured organic EL display device 10, and further improving reliability. It becomes.

  FIG. 5A is a plan view illustrating the method for manufacturing the organic EL display device according to the embodiment of the invention. FIG. 5B is a diagram showing a cross section taken along the cutting line VB-VB of FIG. 5A.

  5A and 5B, a part of the organic film 1131 irradiated with the laser beam L is removed by laser ablation, and the second reflective film 1135b is exposed in a plan view.

  As a result, the reflective film (second reflective film 1135b) that reflects the laser beam L having a predetermined wavelength is a region other than the first region R1 where the organic film 1131 is provided in plan view, and is adjacent to the edge of the first region R1. The second region R2 is formed along the edge of the first region R1.

  Thereafter, the dam material 1137 and the fill material 1138 are formed, and the counter substrate 14 is formed or bonded to the upper surface, whereby the organic EL display device 10 of the present embodiment (the organic EL display device 10 shown in FIGS. 1 and 2). Will be obtained.

  DESCRIPTION OF SYMBOLS 10 Organic EL display device, 11 Circuit board, 12 Integrated circuit chip, 13 Flexible wiring board, 14 Opposite substrate, 111 1st board | substrate, 112 Circuit layer, 113 Element layer, 141 Color filter, 1121 Thin film transistor, 1311, Organic film, 1132 Anode , 1133 cathode, 1134 organic planarization film, 1134b tapered portion, 1134c through hole, 1135 reflection film, 1135a first reflection film, 1135b second reflection film, MB moisture blocking structure, DA display region, CC cathode contact, R1 first Region, R2 Second region.

Claims (6)

An organic film including a light emitting layer;
A predetermined region formed in the second region adjacent to the edge of the first region, along the edge of the first region, in a region other than the first region provided with the organic film in plan view An organic EL display device comprising: a reflective film that reflects a laser beam having a wavelength. The reflective film is provided to surround the display area in a plan view.
The organic EL display device according to claim 1. A common electrode film formed to cover the organic film;
The organic film is provided between the reflective film and the common electrode film.
The organic EL display device according to claim 1 or 2. On the opposite side of the reflective film from the side facing the organic film, the reflective film further includes an organic planarization film formed to overlap with at least a part of the first region in plan view,
The organic planarization film includes a tapered portion having a tapered shape at an end portion,
4. The organic EL display device according to claim 1, wherein at least a part of the reflective film is formed along the shape of the tapered portion. 5. The reflectance of the laser beam of the reflective film is 60% or more.
The organic EL display device according to claim 1, wherein the organic EL display device is an organic EL display device. The reflective film reflects 60% or more of a laser beam having a wavelength of 350 nm or more and 550 nm or less,
The organic EL display device according to claim 1, wherein the organic EL display device is an organic EL display device.

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