KR20100053355A - Wire mask for manufacturing large sized oled and thereof fixing method - Google Patents

Abstract

PURPOSE: A wire mask for a large OLED and a fixing method thereof are provided to reduce manufacturing cost by removing an additional process for manufacturing a large and thin metal mask. CONSTITUTION: Wires are arranged on the both sides of a mask frame(100) and have a certain interval between wires. The interval between wires corresponds to the interval between pixels displaying identical colors. The arranged wires are stretched by a wire stressing apparatus to prevent the deflection of the wire in a deposition process. The stretched wires are fixed to the mask frame by using a welding machine. A wire mask(300) is formed by welding the stretched wires on the mask frame.

Description

Wire mask and manufacturing method for fixing large-area OLEDs

The present invention relates to deposition masks used in large area OLED manufacturing processes. More specifically, the present invention relates to a wire mask that can replace a conventional shadow mask required for a large area OLED manufacturing process.

OLED (Organic Light Emitting Diode) is applied to the display that emits light when an electric current flows through an organic compound, and is being spotlighted as a flat panel display device together with LCD. In the case of LCD, self-illumination is not possible, so the backlight is attached to the back panel to express the color and image of RGB by the action of color filter and liquid crystal.However, unlike LCD, OLED does not require backlight and each RGB has its own fluorescence or It is realized by light emission by phosphorescence. Therefore, OLED devices can have a thinner and lighter configuration than LCDs, can reduce power consumption, and there is no response time delay due to the twisting action of liquid crystals. . In addition, OLEDs have a wider viewing angle than LCDs, exhibit high brightness and high purity colors, and exhibit flexibility such as warpage, thus providing a wide range of applications. Due to the various advantages of the OLED described above, its acceptance is increasing rapidly.

However, OLEDs, which are currently in the spotlight for mobile phone screens, do not meet the demand for larger flat panel displays than LCDs. The display area of the so-called 3.5th generation OLED is 460mm × 720mm or 600mm × 720mm. Furthermore, the fourth generation OLED device of 730mm × 920mm and the fifth generation OLED device of 1100mm × 1300mm are T.V. It will be mounted on the screen.

The difficulty of large area OLED is related to its manufacturing process.

OLED manufacturing uses a patterned thin metal mask (also known as a shadow mask) to deposit a material on a pixel, a shadow mask method, and drops a polymer material on an indium tin oxide (ITO) used as an anode. There is an LITI (Laser Induced Thermal Imaging) method in which a low molecular weight or polymer material coated on a donor film coated with a polymer material is formed on a pixel using an inkjet method for forming a light emitting layer and a laser.

Among the above-described OLED manufacturing methods, the inkjet method has a problem of short lifespan, and the LITI method has a problem in that productivity is reduced since laser processing is required for each pixel as the resolution is increased. Therefore, the shadow mask method is most widely used in terms of lifespan stability and productivity.

Figure 1 shows a general shadow mask method OLED manufacturing method. A shadow mask 30 fixed to the mask frame is disposed below the substrate 10 with a gap therebetween, and the material 40 to form the pixel is formed on the bottom surface of the substrate 10 by vacuum deposition. Shown is a process in which the respective pixels 20 are formed by spraying toward the RGB.

2A shows a plan view and a side view of a conventional shadow mask 30, which is thinly formed of metal and has a predetermined slot 32 such that material is deposited at a predetermined location on the substrate 10. The slot mask 30 has a. In general, several OLED display panels are manufactured by one deposition, and in FIG. 2B, a plan view in which several slot masks 30 are mounted is shown.

3A shows a conventional stripe mask 33 having an opening 34 in the longitudinal direction. 3B shows a plan view in which several stripe masks 33 are mounted.

The masks 30 and 33 of FIGS. 2B and 3B are both fixed to the mask frame 31 by welding.

In the above-described shadow masks 30 and 33, when the thickness is thick, the thickness of the material to be deposited on the substrate 10 is deposited on the edge portion that is covered by the shadow mask and on the center portion that is not covered by the shadow mask. This causes a problem that the cross section of the pixel is not constant. Therefore, the thickness of the shadow masks 30 and 33 should generally be less than 50 μm, and this limitation becomes a factor that makes the mask difficult to manufacture.

In addition, when the mask fabricated in a large area is mounted on the mask frame, the mask is struck downward, making it difficult to precisely arrange pixels in a display having a high resolution as a whole.

In addition, once a difficult mask has been used, the material that adheres to the mask can be cleaned again to be reused. Therefore, development of a mask cleaning method is required.

In addition, the fine metal mask should be precisely aligned with respect to the substrate 10, a mechanism for preventing sagging of the substrate and the mask should be provided, and a cooling mechanism due to the expansion of the mask by radiant heat during deposition will be required. do.

Due to the above-described problems, difficulty in implementing high resolution due to limitations of mask fabrication occurs, and device defects such as line defects and dark spots due to materials remaining in the mask are generated.

The present invention has been made to solve the above-mentioned problems in the manufacture and use of a mask that is becoming larger in area according to the higher resolution of the OLED display in the shadow mask type OLED manufacturing process.

That is, the present invention substitutes a new OLED manufacturing mask that can manufacture a large-area high-resolution OLED display device by eliminating the difficulty of manufacturing a large-area and thin mask (less than 50 μm), sagging of the large-area mask, and cleaning problem of the mask. To provide a device.

Thus, the present invention is fixed in parallel to the mask frame at regular intervals in place of the shadow mask without fabricating the large-area shadow mask used in manufacturing large-area high-resolution OLEDs so that material is deposited on the substrate through the intervals. To provide a wire mask to be able to form pixels.

The present invention provides an OLED manufacturing apparatus for forming a pixel by depositing a material on a substrate,

A wire mask may be provided which is mounted at a lower end of the substrate and arranged in parallel at a predetermined interval to allow the material to be deposited on a predetermined area of the substrate.

In addition, the present invention may provide a wire mask fixed by welding to a mask frame mounted on the bottom of the substrate.

In addition, the present invention may provide a wire mask having a cross section having an inclination angle parallel to the incident angle of the material particles to be deposited.

In addition, the present invention can provide a wire mask having a triangular cross-section having an isosceles side by side with the incident angle of the material particles to be deposited under the distance between the pixels of the same color as the base for manufacturing a full-screen high-definition (full HD) display.

In addition, the present invention in the production of a full-screen high-definition (full HD) display, the cross-sectional shape is a pentagon, the length of the bottom side of the pentagon is 3 to 5% smaller than the distance between the pixels of the same color and two adjacent to the bottom side The two sides that form the convex angle and the inclined sides may provide a wire mask having a pentagonal cross section that forms an angle parallel to the incident angle of the deposited material particles.

In addition, the present invention is a method of fixing the deposition wire mask to the mask frame,

Arranging the plurality of wires at a predetermined interval in the longitudinal direction on the mask frame;

Tensioning the arranged plurality of wires with a stretching device; And

It is possible to provide a method for fixing a wire mask for deposition comprising welding and fixing an end of the stretched plurality of wires to a mask frame with a welder.

According to the present invention, in manufacturing a large area OLED display, a large area and a thin metal mask need not be manufactured by a separate molding process, thereby greatly reducing the manufacturing cost of the large area OLED display.

In addition, low-cost shadow masks can be produced at low cost, and OLED displays, which are currently being applied to small displays, can be extended to large displays, thereby contributing to the expansion of OLED applications.

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

4A shows a plan view, a side view, and a partial enlarged view of a wire mask 300 according to the present invention.

The wires are arranged at regular intervals at opposite opposing displacements of the mask frame 100, the spacing being the spacing between pixels of the same color (see partial enlarged view of the side view). The wires arranged side by side are tightly stretched with a wire stretching device to prevent the sagging of the wires during deposition, and in such a stretched state, the ends of the wires are welded and fixed to the mask frame 100 with a welder.

As described above, the wire mask 300 is completed in a simple process.

4B shows a case of manufacturing four OLED display panels in one deposition process. 4C illustrates a case in which four wire masks 300 are welded on four displays. In this case, in order to minimize the welding process of the wire mask 300, the length of the wire is long enough to cover the two OLED display panels, and thus welding is performed only on two opposite sides 101 and 102 of the mask frame 100. You can also carry out.

4D and 4E, the reinforcing wires 310 and 320 that are thinner than the wires constituting the mask are prepared in case the wires sag during the deposition process or fail to maintain parallel state. Arranged in a weaving form as weaving a weave in a direction perpendicular to the wires of the wire mask 300 or arranged at a predetermined interval on the surface of the wire mask 300 to be fixed by spot welding, or the mask frame 100 with an adhesive It can be fixed on the wire of the image or the wire mask 300. The reinforcing wire 320 arranged in the form of weaving may be made of a material having flexibility.

5 illustrates a process of depositing pixels using two deposition sources 400 and 401. The mask frame 100 and the wire mask 300 are mounted on the substrate 110, and the pixel 330 is formed. The angle and mask thickness of the material particles sprayed during the deposition process are closely related to the so-called shadow effects.

6A, 6B and 6C show the correlation between the shadow effect and the mask thickness. The shadow effect means that when a material particle incident at an inclination angle is deposited on a substrate, the thickness of the pixel prevents the cross section of the pixel from forming a rectangle, and the area of the pixel decreases toward the lower side (the side where the material particle enters). The cross section of the shape refers to the phenomenon of forming an equilateral trapezoidal shape. This shadow effect becomes more serious as the thickness of the mask becomes thicker, and therefore, there is a limitation that the thickness of the conventional mask should be made thinner. This limitation of the mask thickness has been an important factor especially when the pixel size is small.

However, the present invention focuses on the fact that the shadow effect does not occur when the pixel size is large, even if the mask thickness is not as thin as before. Thus, the mask used in the deposition process of the large-area OLED display panel is thicker than before. The wire mask 300 is to be replaced.

7A and 7B are views for explaining a cross section of the mask.

Fig. 7B shows a case of manufacturing an OLED display panel for a 3 inch mobile phone. Pixels 20 of the same color are deposited and arranged at intervals of 777 μm, and the width of the pixel 20 itself is 150 μm. The interval between pixels may change in conjunction with the aperture ratio of the display panel and the resolution. In the case described above, assuming that the angle of the incident particles is 45 ° or more, the ideal mask has a triangle having a base of 627 μm and a height of 313.5 μm. The actual cross section of the mask is a manufacturing problem and is pentagonal or hexagonal rather than triangular.

In FIG. 7A, a 42-inch OLED display panel is manufactured. The width of the pixel 330 itself is 270 μm and the distance between the same pixels is 1460 μm, and the interval may also change in conjunction with the aperture ratio of the display panel and the resolution. . In the above case, assuming that the angle of the incident particle is 45 ° or more, the ideal mask has a triangle having a base of 1190μm and a height of 595μm (much larger than that of 3 inches). The actual cross section of the mask is a manufacturing problem and is pentagonal or hexagonal rather than triangular.

Accordingly, the wire mask of the present invention may have a thickness of approximately 595 μm in the case of a 42 inch display panel.

When the cross section of the wire forms a pentagon, the length of the bottom side of the pentagon is 3 to 5% smaller than the pixel-to-pixel distance of the same color, forming two convex sides and two convex sides adjacent to the bottom side, and two inclined sides are deposited. It forms an angle parallel to the incident angle of the material particles.

Substantially due to manufacturing problems, the cross section of the wire forms a hexagon, and in the pentagonal cross section, a hexagonal cross section is formed by horizontally shaving the vertex portion facing the bottom side, and the length of the horizontally cut side forming the hexagon is inherently 1/5 of the triangle's height is shaved.

As mentioned above, although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. This is possible.

1 is a schematic view showing a deposition process for manufacturing an OLED display panel.

2A is a plan view and a side view of a conventional shadow mask.

2B is a plan view in which several slot masks are mounted.

3A is a plan view and a side view of a conventional stripe mask having an opening in a longitudinal direction.

3B is a plan view in which several stripe masks are mounted.

4A is a partially enlarged plan view, side view, and side view of a wire mask according to the present invention.

4B and 4C are plan views illustrating a case where four OLED display panels are manufactured by one deposition process.

It is a figure which shows further adding the reinforcing wire on the wire mask of this invention.

Figure 4e is a cross-sectional view showing a state in which the flexible reinforcing wire is applied in a weaving manner to the wire mask of the present invention.

5 is a schematic diagram illustrating a process of depositing pixels using two deposition sources.

6A, 6B and 6C are cross-sectional views showing the correlation between the shadow effect and the mask thickness.

7A and 7B are cross-sectional views illustrating a cross section of a mask.

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

31, 100: mask frame 30, 33: shadow mask

10, 110: substrate 300: wire mask

310, 320: reinforcing wire

20, 330: pixel 400, 401: evaporation source

Claims (8)

An OLED manufacturing apparatus for depositing a material on a substrate to form a pixel, And a wire mask for deposition, which is mounted at a lower end of the substrate and arranged in parallel at a predetermined interval to allow the material to be deposited on a predetermined area of the substrate. The deposition wire mask of claim 1, wherein the deposition mask is fixed to a mask frame mounted at a lower end of the substrate by welding. The wire mask for deposition according to claim 1 or 2, having an inclination angle parallel to the incident angle of the material particles to be deposited. The wire mask for depositing a triangular cross section according to claim 3, wherein in manufacturing a large-screen high-definition display, an isosceles side by side with an incident angle of a material particle to be deposited with the distance between pixels of the same color as the bottom side. The method according to claim 4, wherein in the production of a large-screen high-definition display, the cross-sectional shape is pentagonal, and the length of the base of the pentagon is smaller by 3 to 5% with respect to the pixel-to-pixel distance of the same color and the two sides adjacent to the base. Two sides of the wire mask for forming a convex angle and inclined sides are pentagonal cross-sections forming an angle parallel to the incident angle of the deposited material particles. 6. The deposition wire mask of claim 5, wherein the pentagonal cross section has a hexagonal cross section formed by horizontally shaving a vertex portion facing the base. The deposition wire mask of claim 1, further comprising a reinforcing wire fixed in a direction perpendicular to the wire mask to prevent deflection of the wire mask and to maintain parallelism. As a method of fixing the deposition wire mask to the mask frame, Arranging the plurality of wires at a predetermined interval in the longitudinal direction on the mask frame; Tensioning the arranged plurality of wires with a stretching device; And And welding the end of the stretched plurality of wires to a mask frame with a welder.

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