WO2009125882A1

WO2009125882A1 - Manufacturing large size organic light emitting displays

Info

Publication number: WO2009125882A1
Application number: PCT/KR2008/002031
Authority: WO
Inventors: Kug Weon Kim; Byoung Min Moon; Nam Heui Jung; Hwan Kyu Chun; Chang Sang Jo
Original assignee: Soonchunhyang University Industry Academy Cooperation Foundation
Priority date: 2008-04-10
Filing date: 2008-04-10
Publication date: 2009-10-15

Abstract

Techniques for enabling a precise pattern of organic materials to be deposited onto a substrate is are provided. In one embodiment, an apparatus includes a shadow mask for forming patterns on the substrate, and a mask frame for accommodating the shadow mask. The shadow mask has at least two shadow mask sections, each with an aperture pattern through which the materials will be deposited on the substrate. The mask frame is configured to accommodate the shadow mask sections.

Description

MANUFACTURING LARGE SIZE ORGANIC LIGHT

EMITTING DISPLAYS

Technical Field

[I] The described technology relates to Organic Light Emitting displays (OLEDs), and more particularly to apparatuses and methods for manufacturing large size OLED displays.

Brief Description of the Drawings

[2] Figure 1 shows a conventional process of assembling a substrate, a shadow mask and a mask frame for manufacturing large size OLED panels;

[3] Figure 2 shows a state in which a substrate, a shadow mask and a mask frame in

Figure 1 are all assembled;

[4] Figure 3 is a top view of a shadow mask and its divided sections in accordance with one embodiment;

[5] Figure 4 is a top view of a mask frame in accordance with one embodiment;

[6] Figure 5 is a perspective view of a mask frame assembled with a plurality of shadow mask sections in accordance with one embodiment;

[7] Figure 6 shows a process of mounting a shadow mask section within a mask frame in accordance with one embodiment; and

[8] Figure 7 is a sectional view of shadow masks in accordance with one embodiment.

[9] Figure 8 shows a flow diagram of a method for manufacturing a mask frame in accordance with one embodiment.

[10] BACKGROUND

[I I] An OLED display refers to a light-emitting display whose emissive electroluminescent layer comprises a film of organic materials. Recently, OLED displays are increasingly being used in consumer electronics products, such as mobile phones, personal digital assistants (PDA), digital cameras, and various other high-performance display devices in light of their fast response, low power consumption, light weight, wide viewing angle, and the like.

[12] Typically, OLED displays are manufactured through a series of vapor deposition processes to apply thin coatings of organic materials through a shadow mask onto a substrate (such as glass). Shadow masks with aperture patterns are used to pattern the organic electroluminescent layers onto a substrate; and a thermal physical vapor deposition (PVD) process is generally used to pattern organic thin films and metal electrode layers on the substrate.

[13] To reduce manufacturing costs of OLED displays, one approach taken is to fabricate the displays in a batch-type process, in which more than one display is fabricated on a single, large substrate. This approach, however, requires the use of larger shadow masks to pattern coatings on a large substrate.

[14] Figures 1 shows a typical process of assembling a substrate, a shadow mask and a mask frame, for fabricating large size OLED panels. In manufacturing large OLED panels, organic materials are deposited on a substrate 110 through a plurality of aperture sections 120 in a shadow mask 130, which is fitted rigidly to a mask frame 140. Such rigid mask frame is designed to support the shadow mask with a minimal level of mask sag when held in a horizontal orientation. In Figure 1, the shadow mask 130 has four sections of aperture patterns, for fabricating four OLED panels during the vapor deposition process.

[15] Figure 2 shows the state in which the substrate 110, the shadow mask 130 and the mask frame 140 in Figure 1 are all assembled. As shown in Figure 2, as the size of the shadow mask increases, the inner region 210 of the shadow mask 130 would sag under its own weight, making it difficult to deposit precise patterns of organic materials onto the substrate 110.

[16] With the ever increasing need for higher resolution OLED displays, improved alignment and greater dimensional accuracy of shadow masks are needed. To obtain precise patterns for such high resolution displays, the shadow mask 130 needs to be kept as thin as possible and held in intimate contact with the substrate.

[17] As the size of OLED displays continue to increase, together with the increase in the number of panels to be fabricated on a single substrate, the overall size of the shadow mask 130 becomes considerably larger, resulting in mask sag or misalignment over the substrate, adversely affecting the pattern precision of the organic material layer deposited on a substrate.

[18] SUMMARY

[19] Apparatuses and methods for manufacturing large size OLED panels with precise patterns of organic materials are provided. In one embodiment, an apparatus includes a plurality of shadow mask sections for forming precise patterns on a single, large substrate, and a mask frame for supporting the shadow mask sections.

[20] In another embodiment, a shadow mask frame for slidably mounting and supporting a plurality of shadow mask sections is disclosed.

[21] In yet another embodiment, shadow mask sections, each with a pair of opposite edges bent to a predetermined degree are disclosed.

[22] In still yet another embodiment, a method for manufacturing a mask frame includes the steps of providing a mask frame body; forming two or more opening portions in the mask frame body; and forming grooves in each opening portion. In this embodiment, each opening portion of the mask frame body may be for mounting and securing shadow mask sections, and the grooves are to guide and receive edges of the shadow mask sections.

[23] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[24] DETAILED DESCRIPTION

[25] It will be readily understood that the components of the present disclosure, as generally described and illustrated in the Figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of apparatus and methods in accordance with the present disclosure, as represented in the Figures, is not intended to limit the scope of the present claims, but is merely representative of certain examples of presently contemplated embodiments in accordance with the present disclosure. The presently described embodiments can be by reference to the drawings, wherein like parts are designated by like numerals throughout.

[26] Figure 3 is one embodiment of a shadow mask 300 in accordance with the present disclosure, before and after it is divided into a plurality of shadow mask sections 310. Referring to Figure 3, while the shadow mask 300 is divided into four different sections in this embodiment, it is possible to divide it into any number of two or more sections, each with coating apertures for precision patterning organic electroluminescent layers on a substrate.

[27] The shadow mask 300, before it is divided, has a plurality of aperture sections, which are separated from each other by blocking (ineffective) regions 320 and 330 without any apertures. The shadow mask sections 310 can have different aperture patterns, sizes or shapes.

[28] Figure 4 is a top view of one embodiment of a mask frame 400 in accordance with the present disclosure. The mask frame 400 is a support frame for fastening or slidably receiving and securing the shadow mask 300, and is generally provided for structural integrity needed to facilitate the handling of shadow masks without causing damage, and aligning the shadow mask 300 on a substrate for precision patterning.

[29] In Figure 4, the mask frame 400 is designed to hold a plurality of shadow mask sections, and each shadow mask section 310 can be mounted within each opening portion 410 of the mask frame 400. In this example, four shadow mask sections and opening portions are shown, but a different number of shadow mask sections or opening portions (e.g., 7) may be used. In addition, while Figure 4 depicts opening portions 410 of rectangular shape, its shape can be varied depending on the shape of the mask section to be mounted therein. Further, as long as the shadow mask sections can be mounted and secured within the opening portions of the mask frame, the opening portions may have shapes different from those of the shadow mask sections.

[30] Figure 5 is a perspective view of the mask frame 400 with shadow mask sections 310 mounted therein in accordance with one embodiment. Each shadow mask section 310 is mounted and secured within each opening portion 410 of the mask frame 400, with mask junction frames 510 combined to close the opening portions.

[31] With this structure, sagging of the shadow mask can be kept to a minimum for precision patterning needed for higher resolution OLED panels. This also allows for the use of a larger shadow mask 300, which in turn enables the use of a larger substrate to manufacture more OLED panels in a single vapor deposition process. In addition, when one mask section 310 has defects, it can be repaired without replacing the entire shadow mask, by merely replacing the defective section, thereby further lowering the overall OLED fabrication costs.

[32] Upon mounting the shadow mask 300 (with a plurality of mask sections) within the mask frame 400, various traditional fastening methods can also be employed, such as welding, clamping, bolding and the like. For example, certain edges of a shadow mask section 310 can be welded onto the mask frame 400. Further, in this embodiment, although the mask junction frames 510 are used to secure the shadow mask sections 310 to the mask frame 400, they may not be used if the mask sections 310 are fastened to the mask frame 400 with other means for securing the mask sections 310, such as welding, clamping, or other mechanical securing means.

[33] Figure 6 shows the process of fabricating a shadow mask and frame assembly in accordance with one embodiment of the present disclosure, wherein the shadow mask section 310 is slidably mounted within the mask frame 400. The mask frame 400 has grooves 610 and 620 for guiding and receiving the edges of the shadow mask section 310 to be mounted within the mask frame 400. This embodiment eliminates the need for welding the shadow mask 300 to the mask frame 400.

[34] In one embodiment, after fully mounting the mask section within the mask frame

400, a mask junction frame 510 may be combined with the mask frame 400 to complete the shadow mask and frame assembly. However, the shadow mask 300 can be mounted within the mask frame 400 without the use of mask junction frames, by employing various traditional fastening methods, such as welding, bolting, clamping and the like.

[35] Referring to Figure 7, one embodiment of the shadow mask section 310 is illustrated.

Figure 7 is a sectional view of grooves 620 when seen from the "A" side in Figure 6. As shown in Figure 7, the grooves 620 as well as the edges of the shadow mask section 310 are not completely horizontal in this embodiment but are bent to a predetermined degree. With this structure, the shadow mask section 310 has an arch like shape, thereby further limiting sagging of the shadow mask 300 under its own weight.

[36] Figure 8 shows a flow diagram 800 of a method for manufacturing a mask frame in accordance with one embodiment. At step 810, a mask frame body is provided. At step 820, two or more opening portions are formed in the mask frame body. Each opening portion of the mask frame is for mounting and securing shadow mask sections.

[37] At step 830, grooves for guiding and receiving edges of the shadow mask sections are provided in the insides of the opening portions of the mask frame body. Although the grooves are introduced as means for guiding and receiving edges of shadow mask sections, other means may be used if it can be used to mount and secure the shadow mask sections within each opening section of the mask frame.

[38] The present disclosure may be embodied in other specific forms without departing from its basic features or characteristics. Thus, the described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the present disclosure is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

[I] An apparatus for depositing materials onto a substrate, the apparatus comprising: a shadow mask having two or more sections, each with an aperture pattern through which the materials will be deposited on the substrate; and a mask frame configured to accommodate the mask sections therein. [2] The apparatus of Claim 1, wherein the mask frame has grooves configured to slidably receive and guide the mask sections. [3] The apparatus of Claim 2, wherein the grooves and a pair of opposite edges of the shadow mask section are bent to a predetermined degree. [4] The apparatus of Claim 2, wherein the mask frame further comprises mask junction frames configured to secure the shadow mask sections.

[5] The apparatus of Claim 4, wherein the shadow mask sections are rectangular.

[6] A shadow mask frame for producing Organic Light Emitting displays, comprising: two or more opening portions configured to accommodate two or more shadow mask sections. [7] The mask frame of Claim 6, wherein the opening portions have grooves configured to guide and slidably receive the shadow mask sections. [8] The mask frame of Claim 7, wherein the grooves are angled to a predetermined degree. [9] The mask frame of Claim 6, wherein the mask frame further includes mask junction frames configured to close the opening portions. [10] A shadow mask for producing Organic Light Emitting Displays (OLED), comprising: two or more shadow mask sections, each with an aperture pattern through which organic materials will be deposited on a substrate, wherein a pair of opposite edges of each shadow mask section are bent to a predetermined degree.

[I I] An apparatus for depositing materials onto a substrate, the apparatus comprising: means configured to include two or more mask sections, each with an aperture pattern through which the materials will be deposited on the substrate; and means configured to accommodate the mask sections therein.

[12] The apparatus of Claim 11, further comprising means configured to slidably receive and guide the mask sections, wherein a pair of opposite edges of the mask section and at least part of the means configured to slidably receive and guide the mask sections are bent to a predetermined degree.

[13] A method for manufacturing a mask frame, comprising the steps of: providing a mask frame body; forming two or more opening portions in the mask frame body, each opening portion being configured to mount and secure shadow mask sections; and forming grooves in each opening portion, wherein the grooves are configured to guide and receive edges of the shadow mask sections.

[14] The method of Claim 13, wherein at least part of the grooves is bent to a predetermined degree.