Unit mask fixed to a frame with a first bent extension

A unit mask is extended in a direction and is supported by a frame including an opening. The unit mask includes a first fixed part located in the opening and fixed to one surface of the frame disposed in the direction, a second fixed part spaced apart from the first fixed part and fixed to another surface of the frame disposed in the direction, and a mask part held by the first fixed part and the second fixed part between the first fixed part and the second fixed part.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of Korean Patent Application No. 10-2012-0131867 filed in the Korean Intellectual Property Office on Nov. 20, 2012, the entire contents of which are incorporated herein by reference.

BACKGROUND

The described technology relates generally to a unit mask supported by a frame and a mask assembly.

2. Description of the Related Technology

Examples of a flat panel display include an organic light emitting diode (OLED) display, a liquid crystal display (LCD) and a plasma display panel (PDP).

To manufacture the OLED display, it is typically necessary to form an electrode in a specific pattern, and an emission layer. A deposition method using a mask assembly can be used to form the electrode and the emission layer.

A conventional mask assembly generally includes a frame having an opening and a plurality of unit masks in a band shape. Both ends of each unit mask are extended corresponding to the opening and fixed to the frame. The unit masks can include patterned openings corresponding to pixels of OLED displays such that the OLED displays can be manufactured on a mother substrate. The patterned opening of each unit mask can correspond to a single OLED display and is formed in a shape corresponding to an electrode or an emission layer to be formed in the OLED display.

When a high definition OLED display is required, a fine patterned opening is formed in the unit mask. To achieve this, the unit mask needs to be very thin (in μm) in order to prevent unintended deposition error because of characteristics of a deposition process.

However, when the unit mask becomes very thin, it can be difficult to weld both ends of the unit mask to the frame to fix the unit mask to the frame.

Furthermore, when the unit mask is very thin, the unit mask may sag through the opening since both ends thereof are extended and fixed to the frame or the unit mask may deformed due to a tensile force applied to the unit mask.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form a part of the prior art that is already known in this country to a person of ordinary skill in the art.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

The described technology has been made in an effort to provide a unit mask and a mask assembly having advantages of improving deposition reliability when a high definition OLED display is manufactured.

A first aspect of the present invention provides a unit mask extended in a direction and supported by a frame including an opening, the unit mask including a first fixed part located in the opening and fixed to one surface of the frame disposed in the direction, a second fixed part spaced apart from the first fixed part and fixed to another surface of the frame disposed in the one direction, and a mask part held by the first fixed part and the second fixed part between the first fixed part and the second fixed part.

The mask part may be thinner in a perpendicular direction than the first fixed part and the second fixed part.

The first fixed part may include a first bent extension bent and extended downward through the opening, the second fixed part may include a second bent extension bent and extended downward through the opening, and the mask part may include a body extended in the one direction, a first facing part bent and extended from the body through the opening and facing the first bent extension, and a second facing part bent and extended from the body through the opening and facing the second bent extension.

The unit mask may further includes a first block located between the frame and the first bent extension and contacting the first bent extension, and a second block facing the first block with the first bent extension and the first facing part disposed between the first block and the second block and contacting the first facing part.

The second block may be thicker in a perpendicular direction than the first block.

The unit mask may further include a third block located between the first bent extension and the first facing part and contacting the first bent extension and the first facing part.

The unit mask may further include a first fastener penetrating the first bent extension, the first block, the first facing part and the second block to fasten the first bent extension, the first block, the first facing part and the second block.

The surface of the first block contacting the first bent extension and the surface of the second block contacting the first facing part may have uneven shapes.

The surface of the first block contacting the first bent extension, the surface of the second block contacting the first facing part and the surface of the third block contacting the first bent extension and the first facing part may have uneven shapes.

The uneven surface of the second block may be spaced apart from the body of the mask part.

The first bent extension may have an uneven shape corresponding to the uneven surface of the first block and the first facing part may have an uneven shape corresponding to the uneven surface of the second block.

The first bent extension may contact the first facing part.

The unit mask may further include a fourth block located between the frame and the second bent extension and contacting the second bent extension, and a fifth block facing the fourth block, having the second bent extension and the second facing part located between the fourth block and the fifth block, and contacting the second facing part.

The unit mask may further include a sixth block located between the second bent extension and the second facing part and contacting the second bent extension and the second facing part.

The unit mask may further include a second fastener penetrating the second bent extension, the fourth block, the second facing part and the fifth block to fasten the second bent extension, the fourth block, the second facing part and the fifth block.

A second aspect of the present invention provides a mask assembly including a frame including an opening, and the unit mask extended in a direction and supported by the frame.

A third aspect of the present invention provides a method of manufacturing an OLED display including forming an electrode in a specific pattern, and an emission layer on a substrate by deposition using a mask assembly.

The mask assembly may include patterned openings corresponding to pixels of the OLED display.

According to certain embodiments, it is possible to provide a unit mask and a mask assembly having improved deposition reliability when a high definition OLED display is manufactured.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals generally designate like elements throughout the specification.

In disclosed embodiments, the same reference numbers will be used to refer to the same or like parts. A first embodiment is described as a representative embodiment and only parts of other embodiments, which are different from the first embodiment, are described.

In the drawings, dimensions and thicknesses of components may be exaggerated, omitted or schematically illustrated for clarity and convenience of description. In addition, dimensions of constituent elements do not entirely reflect actual dimensions thereof.

In the drawings, the thickness of layers, films, panels, regions, etc., may be exaggerated for clarity. In addition, thicknesses of some layers and areas may be exaggerated for better understanding and ease of description. In the following description of the embodiments, it will be understood that, when an element such as a layer (film), region, pattern, or structure is referred to as being “on” or “under” another element, it can be “directly” on or under another element or can be “indirectly” formed such that an intervening element is also present. Also, terms such as “on” or “under” should be understood on the basis of the drawings.

In addition, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. Furthermore, the expression “on” or “under” may be used herein to represent the relationship of one element to another element as illustrated in the figures. It will be understood that this expression is intended to encompass different orientations of the elements in addition to the orientation depicted in the figures, namely, to encompass both “on” and “under”.

A description will be given of a mask assembly according to a first embodiment with reference toFIG. 1.

FIG. 1is a cross-sectional view of a mask assembly according to a first embodiment.

As shown inFIG. 1, a mask assembly1000according to the first embodiment includes a frame100and a unit mask200.

The frame100fixes and supports both ends of the unit mask200and includes an opening110that exposes the unit mask200. The frame100includes a pair of holders120facing each other in one direction (X direction) in which the unit mask200is extended, having the opening110disposed between the holders120and a pair of other holders (not shown) facing each other in a direction perpendicular to the direction (X direction), having the opening110disposed between the other holders. The holders120hold both ends of the unit mask200. In the frame100of the mask assembly1000according to the first embodiment, the holders120may form long sides of the frame100which may have a rectangular shape and the other holders (not shown) may form short sides of the frame100.

Alternatively, the frame of the mask assembly may have a polygonal or circular shape.

The unit mask200fixed to the frame100is supported by the frame100while a tensile force is applied to the unit mask200. Since a compressive force acts in the direction in which the unit mask200is extended according to the tensile force applied to the unit mask200, the frame100can be formed of a metal having high hardness such as, for example, stainless steel such that the unit mask200is not deformed by the compressive force.

The unit mask200is extended in one direction (X direction) and both ends thereof are fixed to the frame100. The unit mask200includes a patterned opening PO that corresponds to an OLED display and exposes a mother substrate on which the OLED display will be formed during a deposition process. The patterned opening PO is an open pattern corresponding to interconnection lines or an emission layer of the OLED display. A plurality of unit masks200may be provided, and the unit masks200may be arranged in a direction perpendicular to the X direction.

Both ends of the unit mask200are fixed to the frame100while the unit mask200is extended in the X direction. The unit mask200includes a first fixed part210, a second fixed part220, a mask part230, a first block241, a second block242, a third block243, a first fastener250, a fourth block244, a fifth block245, a sixth block246, and a second fastener260.

The first fixed part210is located in the opening110and fixed to the surface of one of the holders120of the frame100, which are disposed in the X direction. The first fixed part210is fixed to the surface of the holder120of the frame100through a fixing method such as welding and includes a first bent extension211that is bent and extended downward from the surface of the holder120through the opening.

The second fixed part220is spaced apart from the first fixed part210and fixed to the surface of the other holder120of the frame100, which are disposed in the X direction. The second fixed part220is fixed to the surface of the other holder120of the frame100through a fixing method such as welding and includes a second bent extension221that is bent and extended downward from the surface of the other holders120through the opening110.

The mask part230is held by the first fixed part210and the second fixed part220between the first fixed part210and the second fixed part220and includes a body231that has the patterned opening OP and is extended in the X direction, a first facing part232that is bent from one end of the body231and extended downward through the opening110and faces the first bent extension211, and a second facing part233that is bent from the other end of the body231and extended downward through the opening110and faces the second bent extension221. The body231, the first fixed part210and the second fixed part220of the mask part230are disposed on a flat virtual straight line. The mother substrate on which deposition will be performed may be located on the body231of the mask part230during a deposition process. In this case, the mother substrate can come into contact with the body231, the first fixed part210and the second fixed part220and a gap is not generated between the unit mask110and the mother substrate since the body231, the first fixed part210and the second fixed part220are disposed on a flat virtual straight line. This improves reliability of deposition using the mask assembly1000.

The mask part230may be thinner than the first fixed part210and the second fixed part220, and thus a fine pattern opening PO can be formed in the thin mask part230. Accordingly, unintended deposition error such as shadow is minimized when the high definition OLED display is manufactured.

The first fixed part210and the second fixed part220may be thicker than the mask part230, and thus the first fixed part210and the second fixed part220can be fixed to the frame100using a welding process. Accordingly, it is possible to securely fix the unit mask200to the frame100through welding regardless of the thickness of the mask part230according to the size of the patterned opening PO.

That is, since the fine patterned opening PO used for a deposition process is formed in the mask part230and the unit mask200is fixed to the frame100by welding the first fixed part210and the second fixed part220to the frame100, it is possible to provide the mask assembly1000having the unit mask200securely fixed to the frame100through welding and improve deposition reliability when a high definition OLED display is manufactured.

The first block241is located between the frame100and the first bent extension211and is in contact with the first bent extension211.

The second block242is located opposite to the first block241having the first bent extension211and the first facing part232disposed between the first and second blocks241and242and is in contact with the first facing part232. The thickness D2 of the second block242is greater than the thickness D1 of the first block241. Since the thickness D2 of the second block242is greater than the thickness D1 of the first block241, a height difference is not generated between the top face of the first fixed part210and the top face of the mask part230and the strength of the mask part230thinner than the first fixed part210is reinforced even when the mask part230is thinner than the first fixed part210.

The third block243is located between the first bent extension211and the first facing part232and is in contact with the first bent extension211and the first facing part232.

The first block241, the second block242and the third block243may have elasticity.

The first fastener250penetrates the first block241, the first bent extension211, the third block243, the first facing part232and the second block242and fastens the first block241, the first bent extension211, the third block243, the second bent extension221and the second block242. The first fastener250may have a screw shape and screw threads can be formed in the first block241, the first bent extension211, the third block243, the second bent extension221and the second block242such that the first fastener250is combined with the screw threads.

The mask part230is held by the first fixed part210according to the first block241, the second block242, the third block243and the first fastener250, and thus strength of the first fixed part210and mask part230is improved and, at the same time, the mask part230is securely fixed to the first fixed part210.

The fourth block244is located between the frame100and the second bent extension221and is in contact with the second bent extension221.

The fifth block245is located opposite to the fourth block244having the second bent extension221and the second facing part233disposed between the fourth and fifth blocks244and245and is in contact with the second facing part233. The fifth block245is thicker than the fourth block244and fifth block245is thicker than the fourth block244, and thus a height difference is not generated between the top face of the second fixed part220and the top face of the mask part230and the strength of the mask part230thinner than the second fixed part220is improved even though the mask part230is thinner than the second fixed part230.

The sixth block246is located between the second bent extension221and the second facing part233and is in contact with the second bent extension221and the second facing part233.

The fourth block244, the fifth block245and the sixth block246may have elasticity.

The second fastener260penetrates the fourth block244, the second bent extension221, the sixth block246, the second facing part233and the fifth block245and fastens the fourth block244, the second bent extension221, the sixth block246, the second facing part233and the fifth block245. The second fastener260may have a screw shape and screw threads may be formed in the fourth block244, the second bent extension221, the sixth block246, the second facing part233and the fifth block245such that the second fastener260penetrating the fourth block244, the second bent extension221, the sixth block246, the second facing part233and the fifth block245is combined with the screw threads.

The mask part230is held by the second fixed part220according to the fourth block244, the fifth block245, the sixth block246and the second fastener260, and thus the strength of the second fixed part220and the mask part230is improved and, at the same time, the mask part230is securely supported by the second fixed part220.

As described above, in the mask assembly1000according to the first embodiment, the unit mask200including the first fixed part210, the second fixed part220, the mask part230, the first block241, the second block242, the third block243, the first fastener250, the fourth block244, the fifth block245, the sixth block246and the second fastener260is extended in the X direction and the first fixed part210and the second fixed part220corresponding to both ends of the unit mask200are fixed to the frame100, and thus the unit mask200is securely fixed to the frame100through welding and deposition reliability when the high definition OLED display is manufactured is improved.

Furthermore, in the mask assembly100according to the first embodiment, the length of the mask part230of the unit mask200, to which a tensile force is actually applied, is shorter than the length of the unit mask200, and thus the mask part230is prevented from sagging through the opening110even though the mask part230is thin. That is, a mask assembly1000having improved deposition reliability of the deposition process is provided.

Moreover, since the mask assembly1000according to the first embodiment is constructed in such a manner that the mask part230having the patterned opening PO is held by the first through sixth blocks241-246, which can have elasticity, between the first fixed part210and the second fixed part220, a tensile force applied to the mask part230is dispersed by the first through sixth blocks241-246, and thus the mask part230is prevented from being deformed according to the tensile force applied to the unit mask200. That is, deformation of the unit mask200due to tensile force is minimized.

A description will be given of a mask assembly according to a second embodiment with reference toFIG. 2.

In the first and second embodiments, the same reference numbers will be used to refer to the same or like parts.

FIG. 2is a cross-sectional view showing part of a mask assembly according to the second embodiment.

As shown inFIG. 2, the unit mask200of a mask assembly1002according to the second embodiment is extended in the X direction and both ends thereof are fixed to the frame100. The unit mask200includes the first fixed part210, the second fixed part220, the mask part230, the first block241, the second block242, the third block243, the first fastener250, the fourth block244, the fifth block245, the sixth block246and the second fastener260.

The surface of the first block241, which is in contact with the first bent extension211, the surface of the second block242, which is in contact with the first facing part232, and both surfaces of the third block243, which come into contact with the first bent extension211and the first facing part232, have uneven shapes. The fourth block244, the fifth block245and the sixth block246may have uneven surfaces.

The uneven surfaces of the first block241, the second block242and the third block243have saw-toothed shapes engaged with the first bent extension211and the first facing part231.

Since the first block241, the second block242and the third block243have uneven surfaces, the first bent extension211has an uneven shape corresponding to the uneven surface of the first block241and the first facing part231has an uneven shape corresponding to the uneven surface of the second block242.

The uneven surface of the second block242is spaced apart from the body231of the mask part230and the uneven surface of the first block241is spaced apart from the top face of the first fixed part210. It is possible to prevent the body231of the mask part230from wrinkling due to the uneven surface of the second block242because the uneven surface of the second block242is spaced apart from the body231of the mask part230.

The first block241, the second block242and the third block243have uneven surfaces and the first bent extension211and the first facing part231have uneven shapes in contact with the first block241, the second block242and the third block243, and thus the first fixed part210and the mask part230are prevented from being detached from the first block241and the second block242when a tensile force is applied to the unit mask200.

That is, the deposition reliability of the mask assembly1002is improved.

A description will be given of a mask assembly according to a third embodiment with reference toFIG. 3.

In the first and third embodiments, the same reference numbers will be used to refer to the same or like parts.

FIG. 3is a cross-sectional view showing part of the mask assembly according to the third embodiment.

As shown inFIG. 3, the unit mask200of the mask assembly1003according to the third embodiment is extended in the X direction and both ends thereof fixed to the frame100. The unit mask200includes the first fixed part210, the second fixed part220, the mask part230, the first block241, the second block242, the first fastener250, the fourth block244, the fifth block245, and the second fastener260.

The surface of the first block241, which is in contact with the first bent extension211, and the surface of the second block242, which is in contact with the first facing part232, have uneven shapes.

The first bent extension211may come into contact with the first facing part232and the second bent extension221may come into contact with the second facing part233.

The uneven surfaces of the first block241and the second block242have saw-toothed shapes engaged with the first bent extension211and the first facing part231.

Since the first block241and the second block242have uneven surfaces, the first bent extension211has an uneven shape corresponding to the uneven surface of the first block and the first facing part231has an uneven shape corresponding to the uneven surface of the second block242.

The uneven surface of the second block242is spaced apart from the body231of the mask part230and the uneven surface of the first block241is spaced apart from the top face of the first fixed part210. Since the uneven surface of the second block242is spaced apart from the body231of the mask part230, the body231of the mask part230is prevented from wrinkling due to the uneven surface of the second block242.

The first block241and the second block242have the uneven surfaces and the first bent extension211and the first facing part have uneven shapes in contact with each other, and thus a tensile force applied to the unit mask200is easily transmitted to the mask part230from the first fixed part210and the second fixed part220.

That is, deposition reliability of the mask assembly1003is improved.

While this disclosure has been described in connection with certain embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.