KR20130046303A - Shadow mask for organic electroluminescent display device and method for fabricating the same - Google Patents

Abstract

PURPOSE: A shadow mask for an organic electroluminescent display device and a manufacturing method thereof are provided to perform a second etching process on a front surface and to secure a high definition opening part. CONSTITUTION: A second thickness region(L2) corresponds to an active area. A second thickness region is separated from the first thickness region(L1). The second thickness region forms a plurality of opening parts. The opening parts correspond to the pixels of a display device. A rib is formed between the opening parts.

Description

Shadow mask for organic electroluminescent display device and method for fabricating the same}

The present invention relates to a shadow mask for an organic light emitting display device and a method of manufacturing the same.

Recently, studies are being actively conducted to increase the display quality of a flat panel display device and attempt to make a large screen. Among these, an organic electroluminescent display device is a self-luminous device that emits light by itself. An organic light emitting display device displays a video image by exciting a fluorescent material using carriers such as electrons and holes.

In addition, the organic light emitting display device has excellent characteristics such as wide viewing angle, high speed response, and high contrast ratio, so that the pixel of a graphic display, the pixel of a television image display, or the surface light source are the same. It is suitable as next-generation flat panel display because it can be used as a thin, light and good color.

On the other hand, the driving method of the organic light emitting display device is classified into a passive matrix type without a separate thin film transistor and an active matrix type organic light emitting display device having a thin film transistor.

In the organic light emitting diode display, organic light emitting diodes are formed in each pixel area, and the organic light emitting diode includes an organic light emitting layer made of an organic light emitting material with an anode and a cathode interposed therebetween.

In addition, the organic light emitting layer of the organic light emitting device includes a plurality of functional layers (hole injection layer, hole transport layer, light emitting layer, electron transport layer, electron injection layer, etc.), and the light emitting performance through the combination and arrangement of such functional layers Will be expressed more.

The organic light emitting layer formed in the pixel region of the organic light emitting display device described above is generally formed by depositing an organic light emitting material on a substrate using a vacuum deposition process.

In the vacuum deposition process, the organic light emitting material forming the organic light emitting layer is placed in a deposition source having an outlet, and the deposition source is heated in a chamber in which the vacuum is maintained to release the organic light emitting material evaporated through the outlet, and the emitted organic light emission The material is deposited on the substrate away from the deposition source.

In the manufacture of such an organic light emitting display device, when there are a plurality of organic light emitting layers having a desired pattern, a deposition process is performed using a shadow mask having a plurality of opening patterns.

After placing the shadow mask having a plurality of openings in close proximity to the substrate, the organic light emitting layer having a plurality of separation patterns in a predetermined pattern form may be formed by depositing the organic light emitting material on the substrate through the shadow mask.

FIG. 1 is a view illustrating a method of forming an organic light emitting layer on a substrate using a shadow mask in general. As shown in FIG. 1, red (R) formed in an active area of an organic light emitting display device, The green (G) and blue (B) organic light emitting layers are formed on the substrate 10 by heating a boat 20 including an organic light emitting material.

That is, when the substrate 10 is loaded in the chamber for forming the organic emission layer, the shadow mask 30 seated on the mask frame 15 is aligned with the substrate 10. Thereafter, the boat 20 containing the red, green, and blue organic light emitting materials is heated, and the red organic light emitting layer R, the green organic light emitting layer G, and the blue organic light emitting layer B are sequentially formed on the substrate 10. Form.

FIG. 2 is a diagram illustrating a structure of a shadow mask used to form an organic light emitting layer of an organic light emitting display device. As shown in FIG. 2, the shadow mask 30 has a slit type as in (a). It is divided into a structure in which the opening 31 is formed, and a structure in which a slot type opening 32 is formed as in (b). A bridge 33 is formed between the opening 32 and the opening 32.

The slit type shadow mask is formed to have the maximum opening ratio to form an organic light emitting layer of the same color in the vertical direction, and the slot type shadow mask forms an opening for each sub pixel. The aperture ratio is reduced compared to the type, but the mechanical strength of the mask is increased.

The conventional shadow mask has a resolution of about 240 [ppi] at maximum, but there is a limit to forming a shadow mask to have a high resolution of 280 [ppi] to 300 [ppi].

In particular, in order to form a high-resolution shadow mask, the openings should be narrow or the distance between the openings should be short. If the openings are simply narrowed, the ribs formed between the openings may stick to each other.

In addition, in the conventional shadow mask manufacturing method, there is a limit in reducing the rib width formed between the openings, so there is a physical limitation in manufacturing a high resolution mask of 240 [ppi] or more.

An object of the present invention is to provide a shadow mask for an organic light emitting display device and a method of manufacturing the same, which can realize high resolution while securing mechanical strength of the shadow mask.

In addition, the present invention provides a shadow for an organic light emitting display device which prevents poor adhesion and twisting of ribs formed between the openings while securing a high resolution opening by performing a second etching process on the front of the shadow mask. Another object is to provide a mask and a method of manufacturing the same.

The shadow mask for an organic light emitting display device of the present invention for solving the above problems of the prior art, in the shadow mask divided into a region having a first thickness (L1) and a region having a second thickness (L2). The area having the second thickness L2 corresponds to the active area of the organic light emitting display device, and the area having the second thickness L2 corresponds to the pixels of the organic light emitting display device. Openings are formed, and a lip having a second thickness L2 is formed between the openings.

In addition, in the shadow mask for an organic light emitting display according to another embodiment of the present invention, a plurality of openings are formed in an area corresponding to a pixel area of the organic light emitting display, and a shadow is formed between the openings. In the mask, the ribs have the same thickness as that of the shadow mask, wherein the ribs have three different first, second and third widths (W1, W2, W3).

In addition, according to another embodiment of the present invention, a method of manufacturing a shadow mask for an organic light emitting display device may include forming a first photoresist layer and a second photoresist layer on both surfaces of a substrate having a first thickness L1. ; Patterning the second photoresist layer to expose a substrate region corresponding to an active region of the organic light emitting display, and then performing a first etching process so that the exposed substrate has a second thickness L2. ; After removing the patterned second photoresist layer, a third photoresist layer is formed on a region having a second thickness of the substrate such that a region corresponding to pixel regions of the organic light emitting display is exposed and a mask is formed. Proceeding with the secondary etching process; And patterning the first photoresist layer, and then etching the substrate using a mask to form a plurality of openings corresponding to pixel regions of the organic light emitting display device, and a lip formed between the openings. do.

In addition, according to another embodiment of the present invention, a method of manufacturing a shadow mask for an organic light emitting display device may include forming a first photoresist layer and a second photoresist layer on both surfaces of a substrate having a first thickness L1. ; Patterning the second photoresist layer to expose a substrate region corresponding to a pixel region of the organic light emitting display device, and then performing a first etching process so that the substrate thickness of the exposed region has a second thickness L2. ; After removing the patterned second photoresist layer, a third photoresist layer is formed on a region having a second thickness of the substrate such that a region corresponding to pixel regions of the organic light emitting display is exposed and a mask is formed. Proceeding with the secondary etching process; And patterning the first photoresist layer, and then etching the substrate using a mask to form a plurality of openings corresponding to pixel regions of the organic light emitting display device, and a lip formed between the openings. do.

In addition, according to another embodiment of the present invention, a method of manufacturing a shadow mask for an organic light emitting display device may include forming a first photoresist layer and a second photoresist layer on both surfaces of a substrate having a first thickness L1. ; The second photoresist layer is patterned to expose a substrate region corresponding to an active region or a pixel region of the organic light emitting display device, and then a first etching process is performed such that the substrate thickness of the exposed region has a second thickness L2. Proceeding; And removing the patterned first and second photoresist layers, and then applying a laser processing process to form a plurality of openings and a lip formed between the openings on a substrate corresponding to the pixel area of the organic light emitting display device. It includes a step.

The shadow mask for the organic light emitting display device and the manufacturing method thereof according to the present invention have the effect of realizing high resolution while ensuring the mechanical strength of the shadow mask.

In addition, the shadow mask for an organic light emitting display device and a method of manufacturing the same according to the present invention, by applying a secondary etching process to the front of the shadow mask to secure a high-resolution opening, the ribs formed between the openings And there is an effect of preventing the twist.

FIG. 1 is a diagram illustrating an example of forming an organic light emitting layer on a substrate using a shadow mask.
FIG. 2 illustrates a structure of a shadow mask used to form an organic light emitting layer of an organic light emitting display device.
3A to 3E illustrate a method of manufacturing a shadow mask for an organic light emitting display device according to a first embodiment of the present invention.
4A to 4E illustrate a method of manufacturing a shadow mask for an organic light emitting display device according to a second embodiment of the present invention.
FIG. 5 is a view showing a rib structure of a shadow mask manufactured by the second embodiment of the present invention. FIG.
6A to 6C illustrate a method of manufacturing a shadow mask for an organic light emitting display device according to a third embodiment of the present invention.
7A to 7C illustrate a method of manufacturing a shadow mask for an organic light emitting display device according to a fourth embodiment of the present invention.
FIG. 8 is a view showing a rib structure of a shadow mask manufactured by the fourth embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the size and thickness of the device may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

3A to 3E illustrate a method of manufacturing a shadow mask for an organic light emitting display device according to a first embodiment of the present invention.

Referring to FIGS. 3A to 3E, after performing a pretreatment process of removing a surface oxide or foreign material from a metal substrate 100 having a predetermined thickness L1, photoresist is applied to both surfaces of the substrate 100. Thus, the first and second photoresist layers 200 and 201 are formed.

First, the second photoresist layer 201 formed on the front surface of the substrate 100 is patterned by performing an exposure and development process, and then used as a mask to correspond to an active area of the organic light emitting display device. The area is first etched. In this case, the etching depth is in the range of 10 to 75% based on the thickness L1 of the substrate 100.

Here, the active area is a display area of the organic light emitting display device, and refers to an area in which a plurality of pixels are formed in a matrix form. Each pixel area includes light emitting devices including red (R), green (G), and blue (B) organic light emitting layers.

In addition, the first photoresist layer 200 formed on the back surface of the substrate 100 serves to prevent the back surface of the substrate 100 from being etched during the etching process.

In the first etching process, the thickness of the substrate 100 corresponding to the active region is reduced to L2, and L2 has a value of 0.25 to 0.9 times the thickness L1 of the substrate 100 according to the etching depth. That is, in the first etching process, a stepped region having a thickness of L2 is formed on the substrate 100 in a region corresponding to the active region of the organic light emitting display device.

As described above, when the active region of the substrate 100 is etched by the primary etching process, as shown in FIGS. 3B and 3C, after removing the patterned second photoresist layer, the third photoresist layer 202 is removed. ) Is formed on the substrate 100. The third photoresist layer 202 is patterned such that the substrate 100 is exposed on a pixel-by-pixel basis with respect to the substrate 100 having a thickness of L2 by performing exposure and development processes.

Next, the substrate 100 corresponding to the pixel area of the organic light emitting display device is secondly etched using the third photoresist layer 202 as a mask.

As described above, when the secondary etching process is performed, as shown in FIGS. 3D and 3E, the first photoresist layer is patterned to form the photoresist pattern 205, and then the second stage etching is performed using the mask as a mask. A third etching process is performed on the back surface of the processed substrate 100 to form the openings OA and the ribs Rib. Thereafter, an ashing process of removing the third photoresist layer and the photoresist pattern 205 is performed to complete the shadow mask 150.

As shown in the drawing, after the substrate region corresponding to the active region of the organic light emitting display device is primarily etched, a secondary etching process for forming the opening is performed to determine the lip R of the shadow mask 150. The thickness has a value of L2.

In addition, the thickness of the shadow mask 150 corresponding to an area other than the active area of the organic light emitting display device has a value of L1.

As described above, according to the present invention, after the front surface of the substrate is etched in two stages, the back surface is etched to form the openings, thereby forming a shadow mask with high resolution while ensuring mechanical strength.

4A to 4E illustrate a method of manufacturing a shadow mask for an organic light emitting display device according to a second embodiment of the present invention.

4A to 4E, after performing a pretreatment process of removing a surface oxide or foreign material from a metal substrate 300 having a predetermined thickness L1, photoresist is applied to both surfaces of the substrate 300. Thus, the first and second photoresist layers 400 and 401 are formed.

First, the second photoresist layer 401 formed on the front surface of the substrate 300 is patterned in units of pixels of the organic light emitting display device through exposure and development processes. Then, using the mask as a mask, the substrate 300 corresponding to the sub pixel of the organic light emitting display device is first etched. The etching depth is in the range of 10 to 75% based on the thickness L1 of the substrate 300.

In this case, the first photoresist layer 400 serves as a protective layer for preventing back etching of the substrate 300.

In the first etching process, the thickness of the substrate 300 corresponding to the pixel area becomes L2, and L2 has a value of about 0.25 to 0.9 times L1 depending on the etching depth. That is, unlike the first embodiment, a step is formed in an area corresponding to the pixel area of the organic light emitting display device in the second embodiment.

As described above, when the substrate 300 is etched by the pixel unit of the organic light emitting display device by the first etching process, as shown in FIGS. 4B and 4C, the second photoresist layer is removed, and then the substrate 300 is removed. ) To form a third photoresist layer 402.

The third photoresist layer 402 may be exposed and developed to pattern the substrate 100 in the pixel region having a thickness of L2.

Next, the substrate 300 corresponding to the pixel area of the organic light emitting display device is secondly etched using the third photoresist layer 402 as a mask.

As described above, when the secondary etching process is performed, as shown in FIGS. 4D and 4E, the first photoresist layer is patterned to form the photoresist pattern 403, and then the second stage etching is performed using the mask as a mask. The third etching process is performed on the back surface of the processed substrate 300 to form the openings OA and the ribs R. Thereafter, an ashing process of removing the third photoresist layer 402 and the photoresist pattern 403 is performed to complete the shadow mask 350.

As shown in the figure, a two-step etching process is performed on the shadow mask area corresponding to the pixel area of the organic light emitting display, so that the total thickness of the ribs formed between the openings OA has a value of L1. In the opening OA region, it has a thickness of L2 due to the two-stage etching. In addition, the thickness of the shadow mask 150 corresponding to an area other than the pixel area of the organic light emitting display device has a value of L1.

As described above, in the present invention, the front surface of the substrate is etched in two stages, and then back etching is performed to form a high-resolution shadow mask, thereby enhancing the mechanical strength of the shadow mask.

FIG. 5 is a view illustrating a rib structure of a shadow mask manufactured according to a second embodiment of the present invention. Referring to FIG. Due to the etching, it has three different first, second and third widths W1, W2, W3. Further, the total thickness of the lip R is equal to the thickness L1 of the shadow mask, and the thickness of the opening region has a value of L2.

Further, the second width W2 of the central portion of the lip R is equal to or larger than half of the sum of the first width W1 of the lip upper surface and the third width W3 of the lower surface. W1 + W3) / 2))

The shadow mask for the organic light emitting display device and the manufacturing method thereof according to the present invention have the effect of realizing high resolution while ensuring the mechanical strength of the shadow mask.

In addition, the shadow mask for an organic light emitting display device and a method of manufacturing the same according to the present invention may be formed by attaching ribs formed between the openings while performing a second etching process on the front of the shadow mask to secure a high resolution opening. It has the effect of preventing the twist.

6A to 6C illustrate a method of manufacturing a shadow mask for an organic light emitting display device according to a third embodiment of the present invention.

6A to 6C, after performing a pretreatment to remove surface oxides or foreign substances from a metal substrate 500 having a predetermined thickness L1, photoresist is applied to both surfaces of the substrate 500. First and second photoresist layers 601 and 602 are formed.

First, the second photoresist layer 201 formed on the front surface of the substrate 500 is patterned by an exposure and development process, and then the substrate corresponding to the active area of the organic light emitting display device is used as a mask. 500) is first etched. The etching depth is in the range of 10 to 75% based on the thickness L1 of the substrate 500.

In this case, the first photoresist layer 601 serves to protect the back surface of the substrate 500 from being etched by an etching process.

The substrate 500 corresponding to the active region in the first etching process has a thickness of L2, and L2 has a thickness of about 0.25 to 0.9 times the thickness of L1 depending on the etching depth.

As described above, when the active region of the substrate 500 is etched by the primary etching process, as shown in the drawing, the openings OA are formed in each active pixel unit in the active region by using the laser 1000. The shadow mask 550 is formed. Ribs R are formed between the openings.

That is, in the third exemplary embodiment of the present invention, the thickness of the substrate 500 corresponding to the active region of the organic light emitting display device is first reduced by an etching process, and then, secondly, by pixel processing using a laser processing process. Openings OA and ribs R were formed.

Accordingly, the shadow mask 550 according to the third embodiment of the present invention has a total thickness of L1 and a lip thickness of the region corresponding to the active region has a value of L2.

As described above, in the present invention, the front surface of the substrate is formed to have a thin thickness by an etching process, and then an opening of the shadow mask is formed by a laser processing process, thereby forming a high-resolution shadow mask while maintaining mechanical strength.

7A to 7C illustrate a method of manufacturing a shadow mask for an organic light emitting display device according to a fourth embodiment of the present invention.

Referring to FIGS. 7A to 7C, after performing a pretreatment process of removing a surface oxide or foreign material from a metal substrate 700 having a predetermined thickness L1, photoresist is applied to both surfaces of the substrate 700. To form first and second photoresist layers 801 and 802.

First, the second photoresist layer 801 formed on the front surface of the substrate 700 is patterned to correspond to the pixels of the organic light emitting display by exposure and development processes, and then the pixels of the organic light emitting display are used as a mask. The substrate 700 corresponding to the sub pixel is etched. The etching depth is in the range of 10 to 75% based on the thickness L1 of the substrate 700.

In the etching process, the substrate 700 corresponding to the pixel area has a thickness of L2, and L2 has a thickness of about 0.25 to 0.9 times of L1 depending on the etching depth. The first photoresist layer 801 serves to protect the back surface of the substrate 700 from being etched by an etching process.

As described above, when the substrate 700 is etched by the pixel by the etching process, as shown in the drawing, the openings OA and the ribs R are formed in each pixel unit by using the laser 1000. The shadow mask 750 is completed.

That is, in the fourth exemplary embodiment of the present invention, the thickness of the substrate 700 corresponding to the pixel area of the organic light emitting display device is reduced by an etching process, and then openings OA are formed pixel by pixel using a laser processing process. It was.

Therefore, the shadow mask 750 according to the fourth embodiment of the present invention has a total thickness of L1 and an overall thickness of the lip R in the region corresponding to the active region also has a value of L1. ) Has a thickness of L2.

As described above, in the present invention, since the front surface of the substrate is etched, the opening of the shadow mask 750 is formed by a laser processing process, thereby enhancing the mechanical strength of the shadow mask 750, thereby achieving a high resolution mask. .

FIG. 8 is a view showing a rib structure of a shadow mask manufactured by the fourth embodiment of the present invention.

Referring to FIG. 8, in the structure of the rib (R) of the shadow mask according to the fourth embodiment, the first etching process is performed at the front of the substrate, and the laser machining process is performed pixel by pixel in a state where a step is generated. Therefore, it has three different fourth, fifth and sixth widths W4, W5, and W6. Further, the total thickness of the lip R is equal to the thickness L1 of the shadow mask, and the thickness of the opening region has a value of L2.

In addition, the fifth width W5 of the center portion of the lip R is equal to or greater than half of the sum of the sixth width W6 of the lip upper surface and the fourth width W4 of the lower surface. W6 + W4) / 2))

The shadow mask for the organic light emitting display device and the manufacturing method thereof according to the present invention have the effect of realizing high resolution while ensuring the mechanical strength of the shadow mask.

In addition, the shadow mask for an organic light emitting display device and a method of manufacturing the same according to the present invention are performed by etching and laser processing on the front of the shadow mask to secure a high-resolution opening, and a rib formed between the openings. There is an effect that prevents poor sticking and twisting.

100 substrate 200 first photoresist layer
201: second photoresist layer 150: shadow mask
OA: Opening R: Rib
1000: laser

Claims (17)

In the shadow mask divided into a region having a first thickness (L1) and a region having a second thickness (L2),
The area having the second thickness L2 corresponds to an active area of the organic light emitting display device, and the area having the second thickness L2 corresponds to a plurality of pixels of the organic light emitting display device. An opening is formed, and a shadow mask having a second thickness L2 is formed between the openings.
2. The shadow mask of claim 1, wherein the second thickness L2 is in a range of 0.25 to 0.9 times the first thickness L1.
In a shadow mask in which a plurality of openings are formed in an area corresponding to a pixel area of an organic light emitting display device, and ribs are formed between the openings,
And wherein the ribs have the same thickness as that of the shadow mask, and the ribs have three different first, second, and third widths (W1, W2, W3).
4. The organic light emitting display device of claim 3, wherein the second thickness L2 of the lip corresponding to the opening area is in a range of 0.25 to 0.9 times the first thickness L1 of the shadow mask. Shadow mask.
4. The organic light emitting display device of claim 3, wherein the second width W2 at the center of the lip is equal to or greater than half of the sum of the first and third widths W1 and W3 on the upper and lower surfaces of the lip. Shadow mask.
Forming a first photoresist layer and a second photoresist layer on both sides of the substrate having a first thickness L1;
Patterning the second photoresist layer to expose a substrate region corresponding to an active region of the organic light emitting display, and then performing a first etching process so that the exposed substrate has a second thickness L2. ;
After removing the patterned second photoresist layer, a third photoresist layer is formed on a region having a second thickness of the substrate such that a region corresponding to pixel regions of the organic light emitting display is exposed and a mask is formed. Proceeding with the secondary etching process; And
Patterning the first photoresist layer, and then etching the substrate using a mask to form a plurality of openings corresponding to pixel regions of the organic light emitting display device, and a lip formed between the openings; A method of manufacturing a shadow mask for an organic light emitting display device.
The organic light emitting display device of claim 6, wherein the second thickness L2 of the substrate formed by the first etching process is in a range of 0.25 to 0.9 times the first thickness L1 of the substrate. Shadow mask manufacturing method.
8. The method of claim 7, wherein the ribs formed between the openings have a second thickness (L2).
Forming a first photoresist layer and a second photoresist layer on both sides of the substrate having a first thickness L1;
Patterning the second photoresist layer to expose a substrate region corresponding to a pixel region of the organic light emitting display device, and then performing a first etching process so that the substrate thickness of the exposed region has a second thickness L2. ;
After removing the patterned second photoresist layer, a third photoresist layer is formed on a region having a second thickness of the substrate such that a region corresponding to pixel regions of the organic light emitting display is exposed and a mask is formed. Proceeding with the secondary etching process; And
Patterning the first photoresist layer, and then etching the substrate using a mask to form a plurality of openings corresponding to pixel regions of the organic light emitting display device, and a lip formed between the openings; A method of manufacturing a shadow mask for an organic light emitting display device.
The organic light emitting display device of claim 9, wherein the second thickness L2 of the substrate formed by the first etching process is in a range of 0.25 to 0.9 times the first thickness L1 of the substrate. Shadow mask manufacturing method.
10. The method of claim 9, wherein the ribs formed between the openings have three different first, second, and third widths (W1, W2, W3). .
12. The organic light emitting display device of claim 11, wherein the second width W2 at the center of the lip is equal to or greater than half of the sum of the first and third widths W1 and W3 on the upper and lower surfaces of the lip. Shadow mask manufacturing method.
Forming a first photoresist layer and a second photoresist layer on both sides of the substrate having a first thickness L1;
The second photoresist layer is patterned to expose a substrate region corresponding to an active region or a pixel region of the organic light emitting display device, and then a first etching process is performed such that the substrate thickness of the exposed region has a second thickness L2. Proceeding; And
After removing the patterned first and second photoresist layers, a laser processing process is applied to form a plurality of openings and ribs formed between the openings on a substrate corresponding to the pixel area of the organic light emitting display device. A method of manufacturing a shadow mask for an organic light emitting display device, comprising the steps of:
The organic field of claim 13, wherein the second thickness L2 of the substrate corresponding to the active region is in a range of 0.25 to 0.9 times the first thickness L1 of the substrate due to the first etching process. Method of manufacturing a shadow mask for a light emitting display device.
15. The method of claim 14, wherein the ribs formed between the openings have a second thickness (L2).
15. The method of claim 13, wherein the ribs formed between the openings have three different first, second and third widths W1, W2, and W3. .
17. The organic light emitting display device of claim 16, wherein the second width W2 at the center of the lip is equal to or greater than half of the sum of the first and third widths W1 and W3 on the upper and lower surfaces of the lip. Shadow mask manufacturing method.

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