Vapor deposition mask

A first region of a valid portion formed on a mask sheet has a shape corresponding to a shape of each of active regions and provided for each active region of a vapor target substrate. A second region of the valid portion is located outside of the first region, and includes a plurality of vapor deposition holes (H) covered with a hauling sheet.

TECHNICAL FIELD

The disclosure relates to a vapor deposition mask and a method for manufacturing the vapor deposition mask.

BACKGROUND ART

As described in PTL 1, a vapor deposition mask is used in the case of patterning and forming a light-emitting layer on each pixel in an organic EL display device.

At the time of preparing the vapor deposition mask, while both end portions of a plurality of mask sheets115each having a strip shape are stretched (pulled) outward as indicated by arrows F4inFIG. 18, portions at or near both the end portions are welded to a mask frame.

The mask sheets115each have a plurality of valid portions YAZ formed. The valid portions YAZ are regions in which a plurality of vapor deposition holes for vapor depositing a vapor-deposition layer for each pixel of a vapor target substrate are formed to be arranged.

In an example inFIG. 18, the valid portions YAZ each have a shape corresponding to a shape of an active region of the vapor target substrate.

Since the plurality of vapor deposition holes corresponding to the pixels are formed in the valid portions YAZ of each of the mask sheets115as described above, the mask sheets115particularly need to have relative positional accuracy with respect to a mask frame.

CITATION LIST

Patent Literature

SUMMARY

Technical Problem

A plurality of vapor deposition holes are formed in a mesh form in a region of a mask sheet115in which valid portions YAZ are formed, and hence, the region has rigidity lower than rigidity of a region outside the valid portions YAZ.

Hence, in the case where both ends of the mask sheet115are stretched outward to attach the mask sheet115to a mask frame, a width W115bin a portion at or near the center115bof each of the valid portions YAZ of the mask sheet115is more likely to be small than a width W115aof a region115abetween the valid portions YAZ.

As described above, since nonuniform stress occurs in the mask sheet115at the time of stretching the mask sheet115, accuracy of a relative position between the vapor deposition holes and the mask frame deteriorates, and as a result, there has been a problem of deterioration in positional accuracy with which a vapor-deposition layer is patterned and formed.

The disclosure has been made in view of the above-described problems of the related art, and an object of the disclosure is to provide a vapor deposition mask that can be used for patterning and forming a vapor-deposition layer with high accuracy.

Solution to Problem

To solve the problems described above, vapor deposition mask according to one aspect of the disclosure provide a vapor deposition mask configured to be used to vapor-deposit a vapor-deposition layer on each of pixels of a vapor target substrate provided with a plurality of active regions on which the pixels contributing to displaying are arranged, the vapor deposition mask including: a mask sheet provided with a valid portion extending across the plurality of active regions and including a plurality of vapor deposition holes formed to be arranged; and a plurality of hauling sheets configured to support the mask sheet, wherein the valid portion includes a first region and a second region, the first region has a shape corresponding to a shape of each of the plurality of active regions, and is provided for each of the plurality of active regions, and the second region defines a shape of the first region, and overlaps with the plurality of hauling sheets to cause a portion of the plurality of vapor deposition holes to be covered.

To solve the problems described above, a method for manufacturing a vapor deposition mask according to one aspect of the disclosure provides a method for manufacturing a vapor deposition mask configured to be used to vapor-deposit a vapor-deposition layer on each of pixels of a vapor target substrate provided with a plurality of active regions on which the pixels contributing to displaying are arranged, the method including: a vapor-deposition-hole forming step for forming a plurality of vapor deposition holes in a mask sheet and providing a valid portion extending across a plurality of the active regions; a hauling-sheet attachment step for attaching a plurality of hauling sheets to a mask frame; and a mask-sheet attachment step for attaching the mask sheet to the mask frame to cause the mask sheet to overlap with the plurality of hauling sheets and to be supported by the plurality of hauling sheets, and providing a first region and a second region in the valid portion, wherein the first region is a region having a shape corresponding to a shape of each of the plurality of active regions, and being provided for each of the plurality of active regions, and the second region is a region defining a shape of the first region, and overlapping with the plurality of hauling sheets to cause a portion of the plurality of vapor deposition holes to be covered.

Advantageous Effects of Disclosure

According to an aspect of the disclosure, an effect in which a vapor deposition mask that can be used for patterning and forming a vapor-deposition layer with high accuracy can be provided.

DESCRIPTION OF EMBODIMENTS

First Embodiment

Outline of Method for Manufacturing Organic EL Display Panel

FIG. 1is a view illustrating manufacturing steps for an organic EL display panel according to a first embodiment.FIG. 2is a plan view of a substrate1of the organic EL display panel according to the first embodiment of the disclosure.FIG. 3is a cross-sectional view of an organic EL display panel formation region of the substrate illustrated inFIG. 2.FIG. 3illustrates a configuration in the case where 18 pieces of organic EL display panels are obtained from one mother glass. Note that the number of the organic EL display panels obtained from one mother glass is not limited to 18, and may be 17 or less or may be 19 or more.

On the substrate1, 18 pieces of organic EL display panel formation regions9are disposed. Each of the organic EL display panel formation regions9is a region cut out from the mother glass into an individual piece and then to be an organic EL display panel.

The substrate1includes a TFT substrate (vapor target substrate)2, an active region3, a frame-shaped bank4, and a sealing layer5.

A plurality of the active regions3are provided in a matrix shape. The active regions3are, for example, regions in which pixels of RGB are formed, respectively. In each of the organic EL display panel formation regions9, a region where the active region3is formed serves as a display region43, and a peripheral region surrounding the active region3serves as a frame region44. Note that, inFIG. 2, the frame region44is a region located outside of a region (active region3) indicated by a dashed line of the organic EL display panel formation region9.

As illustrated inFIGS. 1 to 3, the TFT substrate2is first prepared at TFT step S11. The TFT substrate2is prepared by forming, on the mother glass, a film serving as a base of a flexible substrate by using a material such as polyimide, forming, on the film by a known method, various types of wiring lines present in a pixel circuit provided on each pixel, such as a TFT (a transistor, a driving element), a gate wiring line, and a source wiring line, forming a passivation film (protection film), and an interlayer insulating film (surface leveling film), and the like, and further forming, on the inorganic insulating film, a reflective electrode layer being in contact with an anode, an ITO layer, and a pixel bank (edge cover) for defining a light emitting region.

Accordingly, the light emitting region is formed on the active region3.

The passivation film prevents peeling of the metal film in the TFT, and protects the TFT. The passivation film is formed on the mother glass or via another layer, and covers the TFT. The passivation film is an inorganic insulating film including silicon nitride, silicon oxide, and the like.

The interlayer insulating film provides a leveled surface over irregularities on the passivation film. The interlayer insulating film is formed on the passivation film. The interlayer insulating film is an organic insulating film made of a photosensitive resin such as acrylic, or made of a thermoplastic resin such as polyimide.

In addition, at the time of forming this active region3, the frame-shaped bank4surrounding the active region3in a frame shape is also formed on the TFT substrate2. The frame-shaped bank4is made of a photosensitive resin such as acrylic, or of a thermoplastic resin such as polyimide.

Next, at organic EL step S12, an organic EL layer is formed on the reflective electrode layer in each pixel (namely, in an opening of the pixel bank formed at TFT step S11) of the TFT substrate2. The organic EL layer includes the light-emitting layer, a hole transport layer, and other function layers. The light-emitting layer emits light of a different color such as red, green, or blue for each pixel. At the vapor deposition step, at least one of the light-emitting layer and the hole transport layer (hereinafter, also referred to as the light-emitting layer or the like) is formed at a predetermined position of each pixel by vapor deposition using the vapor deposition mask according to this embodiment in a vacuum.

Prior to the vapor deposition step, the vapor deposition mask used at the vapor deposition step for forming the vapor-deposition layer vapor-deposited for each pixel such as the light-emitting layer and the hole transport layer is prepared in advance at prepare step S20for the vapor deposition mask. Note that details of prepare step S20for the vapor deposition mask will be described later. In addition, the layers formed by using this vapor deposition mask are not limited to the light-emitting layer and the hole transport layer, and may be any layer formed for each pixel (namely, in the opening of the pixel bank).

Then, a transparent electrode facing a reflective electrode via the organic EL layer is formed to cover the organic EL layer.

Then, next, the sealing layer5is formed at sealing step S13. As an example, the sealing layer5can include a three layer structure in which the inorganic layer6, the organic layer7, and the inorganic layer8are layered in this order from the TFT substrate2side. Since the frame-shaped bank4is formed, the organic film7can be formed to have a large thickness of, for example, 1.0 μm or greater.

After this sealing layer5is formed, flexible step S14is performed. At flexible step S14, glass of the substrate is peeled off, and a film or the like serving as a support body is affixed.

Then, next, at singulation step S15, each organic EL display panel formation region9is cut out. Accordingly, each organic EL display panel formation region9is formed as an individual piece. Accordingly, a display panel (organic EL display panel) having flexibility and an irregular shape is formed.

Then, at mounting step S16, a member such as a driver is mounted on each organic EL display panel formation region9formed as an individual piece. Accordingly, the organic EL display device is complete.

In this embodiment, the active region3has, for example, an irregular shape different from a rectangular or square shape, and hence, an external shape of the display panel also has an irregular shape corresponding to the shape of the active region3.

FIG. 4is a schematic view illustrating a state at the vapor deposition step for forming the light-emitting layer or the like (vapor-deposition layer vapor-deposited on each pixel such as the light-emitting layer and the hole transport layer) of the organic EL display device according to the first embodiment of the disclosure.

At the vapor deposition step at which the light-emitting layer or the like is vapor-deposited, a vapor deposition mask10provided with a mask sheet15having a plurality of through-holes is brought into close contact with the TFT substrate2, and in a vacuum, vapor deposition particles Z (for example, an organic light-emitting material) caused to evaporate with a vapor deposition source70are vapor-deposited on the pixels of the TFT substrate2through the mask sheet15. Accordingly, a vapor deposition pattern having a pattern corresponding to the through-hole of the mask sheet15is formed on the TFT substrate2.

FIG. 5is an enlarged view of a portion of the active region3according to the first embodiment. On the active region3, pixels pix contributing to displaying of an image are disposed to be arranged in a matrix shape. On each of the pixels pix, a light-emitting layer80is formed. A peripheral region surrounding the pixels pix serves as a pixel bank bk.

As an example, inFIG. 6, a red pixel Rpix on which a red light-emitting layer80R configured to emit red light is formed, a green pixel Gpix including a green light-emitting layer80G configured to emit green light, and a blue pixel Bpix including a blue light-emitting layer80B configured to emit blue light are arranged in a pentile matrix. However, the pixel arrangement is not particularly limited to the pentile matrix, and may be other arrangement such as stripe arrangement.

Note that a shape of the light-emitting layer80is a shape of the opening of the pixel bank bk in which the light-emitting layer80is formed.

Vapor Deposition Mask

Next, prepare step S20for the vapor deposition mask used at the vapor deposition step will be described.FIG. 6is a view illustrating the vapor deposition step for the light-emitting layer of the organic EL display panel according to the first embodiment.FIGS. 7A to 7Fare views each illustrating a state where the vapor deposition mask according to the first embodiment is prepared.FIG. 7Ais a plan view illustrating a mask frame.FIG. 7Bis a view illustrating a state where a covering sheet is attached to the mask frame.FIG. 7Cis a view illustrating a state where a hauling sheet is attached to the mask frame.FIG. 7Dis a view illustrating a state where an alignment sheet is attached to the mask frame.FIG. 7Eis a view illustrating a state where a mask sheet is attached to the mask frame.FIG. 7Fis a plan view of the vapor deposition mask prepared.

As illustrated at step Sa inFIG. 6and illustrated inFIGS. 7A and 7B, a plurality of covering sheets12are attached to a mask frame11having a frame shape and including a frame opening11ain a region surrounded by the frame (covering-sheet attachment step).

For example, an invar material or the like having a significantly low thermal expansion and a thickness ranging from 20 mm to 30 mm is used as a base material of the mask frame11. The mask frame11is sufficiently thick as compared to the mask sheet, and has high rigidity to enable sufficient accuracy to be secured even at the time of stretching and welding of the mask sheet.

The covering sheets12each serve to fill a gap between mask sheets to be subsequently attached to the mask frame11, and serve to close a dummy pattern formed on the mask sheet.

For example, an invar material or the like having a thickness ranging from 30 μm to 50 μm is used as a base material of the covering sheets12. The covering sheets12each have an elongated shape, and extends in a straight manner from one end portion to the other end portion.

At the time of attachment of the covering sheets12to the mask frame11, both end portions of the covering sheets12are welded to insides of grooves provided in the mask frame11while both the end portions of the covering sheets12are stretched (pulled) by application of force to each of both the end portions of the covering sheets12in an outward direction (in a direction away from each other) as indicated by arrow F1inFIG. 7B. Then, unnecessary portions located outside of the welded portions of the covering sheets12are cut off. Accordingly, each of the covering sheets12is attached at a predetermined position of the mask frame11. In this embodiment, the covering sheets12are attached to the mask frame11to be parallel to each other in a shorter side direction of the mask frame11. The covering sheets12are attached to the mask frame11to be arranged on a longer side of the mask frame11and to be parallel to each other.

Next, as illustrated at step Sb inFIG. 6and illustrated inFIG. 7C, hauling sheets13(also referred to as support sheets) are attached to the mask frame11to which the covering sheets12are attached (hauling-sheet attachment step).

The hauling sheets13serve to support a mask sheet that is subsequently to be attached to the mask frame11without being loosened, and serve to close a dummy pattern formed on the mask sheet.

In addition, in this embodiment, as will be described later, the hauling sheets13also serve to cover vapor deposition holes located outside of a region corresponding to the active region, which are a portion of the plurality of vapor deposition holes present in a valid portion YA provided on the mask sheet15.

For example, an invar material or the like having a thickness ranging from 30 μm to 100 μm is used as a base material of the hauling sheets13. A width of each of the hauling sheets13ranges, for example, from approximately 8 mm to 10 mm, and is determined according to layout on a substrate on which a panel is disposed. The howling sheets13each have an elongated shape, and each extend in a straight manner from one end portion to the other end portion.

Typically, in a display panel having a portrait shape, since a terminal portion is masked with a hauling sheet, a width of the hauling sheet is larger than a width of the covering sheet, but the hauling sheet is disposed at a position where the hauling sheet does not overlap with a display region (namely, a valid portion of a mask sheet) of the display panel.

At the time of attachment of the hauling sheets13to the mask frame11, both end portions of the hauling sheets13are welded to insides of grooves provided in the mask frame11while both the end portions of the hauling sheets13are stretched (pulled) by application of force in an outward direction (in a direction away from each other) as indicated by arrow F2inFIG. 7C. Then, unnecessary portions located outside of the welded portions of the hauling sheets13are cut off. Accordingly, each of the hauling sheets13is attached at a predetermined position of the mask frame11.

In this embodiment, the hauling sheets13are attached to the mask frame11to be parallel to each other on the longer side of the mask frame11. The hauling sheets13are attached to the mask frame11to be arranged in the shorter side direction of the mask frame11and to be parallel to each other.

Note that the order of attachment of the covering sheets12and the hauling sheets13to the mask frame11may be reversed (reverse the order of step Sa and step Sb inFIG. 6), and the hauling sheets13may first be attached to the mask frame11, and then, the covering sheets12may be attached to the mask frame11.

The plurality of covering sheets12and a plurality of the hauling sheets13are attached to the mask frame11in a lattice pattern as illustrated inFIG. 7C, and accordingly, openings each defined by the covering sheets12facing each other and the hauling sheets13facing each other are formed to be arranged.

Next, as illustrated at step Sc inFIG. 6and illustrated inFIG. 7D, alignment sheets14including alignment marks formed are attached to the mask frame11to make the alignment marks located at predetermined positions (alignment-sheet attachment step).

At the time of attachment of the alignment sheets14to the mask frame11, both end portions of the alignment sheets14are welded to predetermined positions of the mask frame11while both the end portions of the alignment sheets14are stretched (pulled) by application of force to each of both the end portions of the alignment sheets14in an outward direction (in a direction away from each other) and in a direction parallel to the short-hand direction of the mask frame11as indicated by arrow F3inFIG. 7D. Then, unnecessary portions located outside of the welded portions of the alignment sheets14are cut off. Accordingly, each of the alignment sheets14is attached at a predetermined position of the mask frame11. In this embodiment, two alignment sheets14are attached to the mask frame11to be parallel to each other along a shorter side of the frame opening11aof the mask frame11.

Next, as illustrated at step Sd inFIG. 6and illustrated inFIG. 7E, a plurality of the mask sheets15are attached to the mask frame11(mask-sheet attachment step). The mask sheets15are sheets used, for example, for separately patterning RGB to pattern and form the vapor-deposition layer in the pixels in the active region3illustrated inFIGS. 2 and 3. At step Sd, a first region YA1and a second region YA2are provided in the valid portion YA of the mask sheet15.

In addition, prior to step Sd and before the mask sheets15are attached to the mask frame11, a plurality of vapor deposition holes are formed to be arranged, and thereby, the valid portion YA on the mask sheet15is formed at step S101(valid-portion forming step). The valid portion YA extends across the active regions3, namely, has area to the extent that the valid portion YA substantially overlaps with the plurality of active regions3. Details of the valid portion YA, the first region YA1, and the second region YA2will be described in detail later.

At step Sd, at the time of attachment of the mask sheet15to the mask frame11, both end portions of the mask sheet15are accurately welded at predetermined positions of the mask frame11to make the vapor deposition holes constituting the valid portion YA located at a predetermined position by using the alignment mark formed on the alignment sheet14as a reference while both the end portions of the mask sheet15are stretched (pulled) by application of force to each of both the end portions of the mask sheet15in an outward direction (in a direction away from each other) as indicated by arrow F4inFIG. 7E.

In addition, at the time of stretching and welding of the mask sheet15, the stretching and welding are performed while counter force is applied on the mask frame11according to an amount of deformation of the mask sheet15obtained after the stretching and welding. Accordingly, the mask sheet15is attached to the mask frame11to make an extending direction of the valid portion YA intersect at a right angle an extending direction of each hauling sheet13.

Then, after all the necessary sheets of the mask sheets15are attached to the mask frame11to cause all the openings defined by the covering sheets12and the hauling sheets13to be covered with the valid portions YA as illustrated inFIG. 7F, unnecessary portions located outside of the welded portions of the mask sheets15are cut off as illustrated at step Se inFIG. 6and illustrated inFIG. 7F.

Next, as illustrated at step Sg inFIG. 6, the vapor deposition mask10complete is cleaned, and various mask inspections such as an inspection for foreign matters and an inspection for accuracy are performed. Subsequently, vapor deposition masks10having no problem found in the mask inspections are stored in a stocker, and are supplied to a vapor deposition apparatus used at the vapor deposition step as needed.

Valid Portion YA

FIGS. 8A to 8Dare views each illustrating a configuration of the mask sheet15according to the first embodiment.FIG. 8Ais a plan view of the mask sheet15.FIG. 8Bis an enlarged view of the valid portion illustrated inFIG. 8A.FIG. 8Cis a cross-sectional view taken along line B-B illustrated inFIG. 8B.FIG. 8Dis a cross-sectional view taken along line C-C illustrated inFIG. 8B.

As illustrated inFIG. 8A, the mask sheet15has a strip shape, and for example, an invar material or the like having a thickness ranging from 10 μm to 50 μm, preferably, a thickness of approximately 25 μm is used as a base material of the mask sheet15. To prevent the vapor-deposition layer vapor-deposited from having a nonuniform thickness, the mask sheet15includes a sheet having a small thickness.

The valid portion YA extending in a longitudinal direction of the mask sheets15is formed between both the end portions of the mask sheet15. In the valid portion YA, a plurality of vapor deposition holes H corresponding to the pixels are formed to be arranged. The valid portion YA extends across the plurality of active regions3of the TFT substrate2, and has area to the extent that the valid portion YA substantially overlaps with the plurality of active regions3.

The valid portion YA overlaps with a plurality of hauling sheets13(FIGS. 7E and 7F). In this embodiment, of the plurality of hauling sheets13, hauling sheets13zlocated at both ends overlap with portions at or near both end portions YAa of the valid portion YA. A region YAb between regions overlapping with the hauling sheets13zlocated at both ends of the valid portion YA is a region including a region overlapping with each active region3. In this embodiment, the region YAb of the valid portion YA has a constant width (a length in a direction perpendicular to the extending direction) even in a state where the mask sheet15is stretched. Then, of the mask sheet15, a region where the region YAb of the valid portion YA is provided also has a constant width even in a state where the mask sheet15is stretched.

Hence, in a portion at or near the region YAb of the valid portion YA of the mask sheet15, stress applied when the mask sheet15is stretched becomes uniform. Accordingly, the mask sheet15can be stretched and attached to the mask frame11with high accuracy at the mask-sheet attachment step.

In addition, of the mask sheet15, the regions located outside of the region YAb of the valid portion YA, namely, the regions overlapping with the hauling sheets13zat both the ends each have a width gradually increasing outward.

As illustrated inFIGS. 7E and 7FandFIG. 8B, the valid portion YA includes the first region YA1and the second region YA2. The first region YA1is formed for each active region3(seeFIG. 2), and has a shape corresponding to a shape of the active region3. The second region YA2is a region of the valid portion YA different from the first region YA1, and is a region overlapping with the hauling sheet13. The region YAb of the valid portion YA illustrated inFIG. 8Aand having a constant width is a region including the first region YA1and the second region YA2located between first regions YA1.

As illustrated inFIG. 8B, in the valid portion YA, the vapor deposition holes H present in the first region YA penetrate, and the vapor deposition holes H present in the second region YA2are covered with the hauling sheet13.

The vapor deposition holes H present in the first region YA are vapor deposition holes for patterning and forming of the vapor-deposition layer for each pixel. The vapor deposition holes H present in the second region YA2are dummy vapor deposition holes not contributing to patterning and forming of the vapor-deposition layer for each pixel.

At the vapor deposition step, the first region YA1of the valid portion YA of the mask sheet15overlaps with the active region3(seeFIGS. 2 and 3) of the TFT substrate2, and the second region YA2located outside of the first region YA1and an edge portion surrounding the valid portion YA overlap with the frame region44(seeFIGS. 2 and 3). Then, vapor deposition particles coming from the vapor deposition source pass through the vapor deposition holes H present in the first region YA1, and are vapor-deposited on the pixels of the active region3of the TFT substrate2. At this time, the second region YA2and the edge portion surrounding the valid portion YA of the mask sheet15overlap with the frame region44of the TFT substrate2, and hence, vapor deposition particles are blocked by the second region YA2and the edge portion surrounding the valid portion YA, and do not arrive at the frame region44.

In the case where the light-emitting layer is vapor-deposited on the TFT substrate through the mask sheet15, the vapor deposition holes H are formed in the valid portion YA to correspond to a formation region for a light-emitting layer configured to emit light of any of colors that the light-emitting layers emit. For example, in the case where the light-emitting layer configured to emit red light, the light-emitting layer configured to emit green light, and the light-emitting layer configured to emit blue light are formed in the active region3, the vapor deposition holes H are formed in the same pattern as a pattern of any of the light-emitting layer configured to emit red light, the light-emitting layer configured to emit green light, and the light-emitting layer configured to emit blue light.

The vapor deposition holes H of the second region YA2are the same as the vapor deposition holes H of the first region YA1in a pitch and a shape.

Of the valid portion YA, the regions overlapping with the active region3and the regions located between the regions overlapping with this active region3include a combination of the first region YA1and the second region YA2to have a rectangular or square shape different from an irregular shape.

Note that the irregular shape is a shape in which at least a portion of an edge (a side or a corner) in the case where an external shape of an organic EL display panel is a rectangular or square shape includes an irregular-shape portion protruding inwardly (a central portion direction of the rectangular or square shape) or outwardly (in a direction away from the central portion of the rectangular or square shape) from the edge. The irregular-shape portion refers to a portion having a shape different from a rectangular or square shape, such as a shape in which corners are curved, rather than right-angled, that is, the corners each have a so-called rounded shape (round shape), and a shape in which at least one side of four sides has a notched portion recessed to protrude from an edge in the central portion direction.

At step S101illustrated inFIG. 6, the vapor deposition holes H are prepared in the mask sheet15, for example, in the following manner.

First, a negative-working or positive-working photosensitive resist is applied to both surfaces of an elongated plate made of an invar material to form resist films on both main surfaces (a first surface and a second surface).

Then, the resist films of the first surface and the second surface are subjected to exposure and developing using an exposure mask to form resist patterns on both surfaces of the elongated plate. Then, the resist pattern on the first surface is used as a mask to perform etching of a first surface15b(surface facing the TFT substrate2at the time of vapor deposition) of the valid portion YA (etching of an upper face of the edge portion is not performed), and openings K are formed on the first surface15bof the valid portion YA (at this stage, the openings K are still not vapor deposition holes penetrating).

Then, the first surface15bis covered with a resistant resin having an etching resistant property, and the resist pattern on a second surface15c(surface opposite to the surface facing the TFT substrate2at the time of vapor deposition) is used as a mask to perform etching of the valid portion YA and a lower face of the edge portion. Accordingly, the vapor deposition holes H (through-holes) are formed in the valid portion YA by erosion from the second surface15cside to form a plurality of recesses on the lower face of the edge portion.

The plurality of vapor deposition holes H of the valid portion YA are formed in a matrix shape or an oblique lattice pattern in the longitudinal direction and the short-hand direction (width direction) of the mask sheet15. The openings K of the plurality of vapor deposition holes H (openings on the upper face) are shaped into a quadrangle shape including corners each having a round shape, or a circular shape or an elliptic shape to correspond to a shape of an opening of a pixel bank layer of the substrate. In the valid portion YA, etching of each of the vapor deposition holes H on the second surface15cside is performed in a more extensive and deeper manner than on the first surface15bside, and thereby, a shading portion (a height of a partition between two adjacent vapor deposition holes) is made small, and vapor deposition accuracy and vapor deposition efficiency relative to the substrate can be enhanced.

The valid portion YA has a configuration in which when a cross section is taken along line B-B passing through the center of two openings K adjacent in the lateral direction, the base material becomes minimum (a cavity is maximum) as illustrated inFIG. 8C; and when a cross section is taken along line C-C parallel to line B-B and passing through a point located equidistant from two openings K adjacent in the vertical direction, the base material becomes maximum (a cavity is minimum) (a maximum thickness is equal to a thickness Ti of the base material) as illustrated inFIGS. 8C and 8D. Accordingly, the mask sheet15is prepared.

FIG. 9is a view illustrating a state of a portion of the vapor deposition mask10as viewed from the second surface15cside.FIG. 10is a cross-sectional view of the vapor deposition mask10and the TFT substrate2at the time of performing vapor deposition at the vapor deposition step.

As illustrated inFIGS. 9 and 10, the valid portion YA in which the plurality of vapor deposition holes are formed to be arranged is provided to extend across the plurality of active regions3. Then, the valid portion YA includes the first region YA1and the second region YA2.

The first region YA1has a shape corresponding to a shape of the active region3, and is provided for each active region3. Then, the second region YA2defines a shape of the first region YA1, and overlaps with the hauling sheet13to cause the vapor deposition holes H to be covered.

Hence, at the time of stretching the mask sheet15to attach the mask sheet15to the mask frame11(FIG. 7E), stress is uniformly applied on the first region YA1and on a region located in a portion at or near the second region YA2sandwiched between the first regions YA1of the mask sheet15. Accordingly, the mask sheet15can be attached to the mask frame11with enhanced relative positional accuracy of each vapor deposition hole and the mask frame11. As a result, the vapor deposition mask10that can be used for patterning and forming a vapor-deposition layer with high accuracy can be obtained.

In addition, a position and a shape of the second region YA2defining an external shape of the first region YA1can be defined by a position and a shape of the hauling sheet13. Hence, since it is not necessary to change the external shape of the valid portion YA even when the external shape of the active region3changes, commonality of the mask sheet15including the valid portion YA formed can be achieved between substrates having various external shapes.

For example, the commonality of the mask sheet15used to form the active regions3having different aspect ratios such as 4:3, 16:9, and 18:9 can be achieved.

In addition, as illustrated inFIG. 10, each hauling sheet13is in contact with the second surface15cof the mask sheet15located on the opposite side to the first surface15bfacing the TFT substrate2. Accordingly, occurrence of a shadow due to a distance between the TFT substrate2and each hauling sheet13can be prevented at the time of vapor deposition for the TFT substrate2.

FIG. 11is an enlarged view of a portion at or near the second region YA2of the valid portion YA according to the first embodiment. In this embodiment, a pitch W2at which the vapor deposition holes H present in the second region YA2are arranged is preferably equal to a pitch at which the vapor deposition holes H present in the first region YA1are arranged as illustrated inFIG. 11. Accordingly, formation of the valid portion YA is facilitated.

In addition, in the valid portion YA, a width W1between the first regions YA1is set to an integral multiple of the pitch W2of the vapor deposition holes H. Accordingly, formation of the valid portion YA is facilitated.

In this embodiment, further, shapes of the vapor deposition holes H present in the first region are the same as shapes of the vapor deposition holes H present in the second region YA2.

Second Embodiment

FIG. 12is a view illustrating a configuration of a mask sheet15according to a second embodiment. As illustrated inFIG. 12, vapor deposition holes, namely, valid portions YA are formed on all the mask sheet15.FIG. 13is a view illustrating a configuration of a vapor deposition mask10according to the second embodiment. In the vapor deposition mask10illustrated inFIG. 13, a plurality of mask sheets15illustrated inFIG. 12are attached to the mask frame11.

In the vapor deposition mask10illustrated inFIG. 13, the valid portions YA of each mask sheet15each are provided to extend across a plurality of active regions3. Then, each of the valid portions YA has a first region YA1having a shape corresponding to a shape of each of the active regions3(FIGS. 2 and 3), and a second region YA2overlapping with a hauling sheet13.

In the mask sheet15illustrated inFIGS. 12 and 13, at the time of stretching the mask sheet15to attach the mask sheet15to the mask frame11(FIG. 7E), stress is uniformly applied on the first region YA1and on a region located in a portion at or near the second region YA2sandwiched between first regions YA1of the mask sheet15.

In particular, in the mask sheet15illustrated inFIGS. 12 and 13, since the valid portion YA is provided on all the mask sheet15, stress occurring at the time of stretching the mask sheet15is more uniformly applied on all the mask sheet15. Accordingly, the mask sheet15can be attached to the mask frame11with enhanced relative positional accuracy of each vapor deposition hole and the mask frame11. As a result, the vapor deposition mask10that can be used for patterning and forming a vapor-deposition layer with high accuracy can be obtained.

In addition, a position and a shape of the second region YA2defining an external shape of the first region YA1can be defined by a position and a shape of the hauling sheet13. Hence, since it is not necessary to change an external shape of the valid portion YA even when an external shape of the active region3changes, commonality of the mask sheet15including the valid portion YA formed can be achieved between substrates having various external shapes.

Third Embodiment

FIG. 14is a view illustrating a configuration of a mask sheet15according to a third embodiment.FIG. 15is a view illustrating a state where the mask sheet15illustrated inFIG. 14is stretched to be attached to the mask frame11.

Here, in a valid portion of the mask sheet, rigidity at a central portion is relatively smaller than rigidity at both end portions.

Thereby, in the mask sheet15illustrated inFIG. 14, a valid portion YA has a width gradually increasing from both the end portions toward the central portion. Then, a width of the mask sheet15gradually increases from a width W15aat each of positions including both the end portions of the valid portion YA, toward a width W15bat a position including the central portion of the valid portion YA.

Hence, at the time of stretching both ends of the mask sheet15outward as indicated by arrow F4as illustrated inFIG. 15, the extent of decrease in the width at the central portion of the valid portion YA is greater than the extent of decrease in the width at each of both end portions of the valid portion YA. As both the ends of the mask sheet15are stretched, a width W15cof the mask sheet15at each of positions including both the end portions of the valid portion YA is the same as a width W15dat a position including the central portion of the valid portion YA.

Accordingly, positional accuracy of vapor deposition holes relative to the mask frame can be improved.

Fourth Embodiment

FIG. 16is a view illustrating a configuration of a hauling sheet13according to a third embodiment.FIG. 17is a view illustrating a state of a portion of a vapor deposition mask according to the fourth embodiment as viewed from a second surface15cside.

In the case where vapor deposition is performed on an active region having an irregular shape, a hauling sheet13is provided with a shape corresponding to a shape of an irregular-shape portion as illustrated inFIG. 16.

As illustrated inFIG. 16, the hauling sheet13according to this embodiment is provided with a convex and a recess or the like including a shape of the irregular-shape portion of the external shape of the active region, and extending from one end portion to the other end portion. The hauling sheet13includes attachment regions13abeing regions located in portions at or near both end portions of the hauling sheet and overlapping with the mask frame11when the hauling sheet13is attached to the mask frame11(FIG. 7C), and includes an external-shape forming region13bof an active region being a region located between the attachment regions13aand forming the external shape of the active region.

The external-shape forming region13bof the active region has an uneven shape for forming the external shape of at least a portion of the active region including the irregular-shape portion of the active region.

Of the external-shape forming region13bof the active region, notched portions13care formed to be arranged on one side extending in an extending direction, and notched portions13dare formed to be arranged on the other side extending in the extending direction.

The notched portions13cand13deach have a shape corresponding to a shape of the irregular-shape portion, for example, having an arc shape of the active region, such as a notched portion43dand four corners43ato43d.

The notched portions13ceach include curved portions23cand23dfor forming adjacent two corners each having a round shape and being the irregular-shape portion of the active region. The notched portions13deach include curved portions23aand23bfor forming adjacent two corners each having a round shape and being the irregular-shape portion of the active region, and also each include a protruding portion23ehaving a protruding shape of the same shape as a shape of a notch of the active region, and being provided between the curved portions23aand23b.

A plurality of the hauling sheets13illustrated inFIG. 16are attached to the mask frame11in parallel (FIG. 7C), and a mask sheet15is attached to the mask frame11(FIGS. 7E and 7F).

Then, according to the hauling sheet13illustrated inFIG. 16, an external shape of a first region YA1is defined by the curved portion23a, the protruding portion23e, the curved portion23b, the curved portion23c, and the curved portion23deach serving as the irregular-shape portion.

The protruding portion23eis a notch provided on one side of the first region YA1and protruding from this one side toward an interior direction of this first region YA1. The curved portions23ato23ddefine a shape in which four corners of the first region YA1each have a round shape. Vapor deposition holes in the first region YA1surrounded by the curved portion23a, the protruding portion23e, the curved portion23b, the curved portion23c, and the curved portion23dare not covered with the hauling sheet13, and are through-holes. On the other hand, vapor deposition holes located outside the first region YA1in the curved portion23a, the protruding portion23e, the curved portion23b, the curved portion23c, and the curved portion23dare covered with the hauling sheet13.

As such, according to the first region YA1having an irregular-shape portion, a vapor-deposition layer is formed on each pixel of the active region having the same external shape as the shape of the first region YA1, namely, having the irregular-shape portion.

According to the vapor deposition mask10according to this embodiment, a valid portion does not need to correspond to the shape of the active region having the irregular-shape portion, and hence, the valid portion can have a shape in which at least an external shape of a region extending across a plurality of active regions and overlapping with the plurality of active regions has a square or rectangular shape. Accordingly, stress applied when the mask sheet15is stretched can be made uniform, and the mask sheet15can be attached to the mask frame11with high accuracy.

In addition, since the valid portion does not need to correspond to the shape of the active region having the irregular-shape portion, commonality of the mask sheet15having the valid portion YA formed can be achieved between substrates with various external shapes.

Note that the notches and the corners each having the round shape as described above are merely examples of the shape of irregular-shape portion, and the irregular-shape portion may have other irregular shapes.

In addition, the display according to the first to fourth embodiments is not particularly limited, and is a display panel including a display element. The display element is a display element of which luminance and transmittance are controlled by an electric current, and examples of the electric current-controlled display element include an organic Electro Luminescence (EL) display provided with an Organic Light Emitting Diode (OLED), an EL display such as an inorganic EL display provided with an inorganic light emitting diode, and a QLED display provided with a Quantum Dot Light Emitting Diode (QLED).

Supplement

A vapor deposition mask according to a first aspect provides a vapor deposition mask configured to be used to vapor-deposit a vapor-deposition layer on each of pixels of a vapor target substrate provided with a plurality of active regions on which the pixels contributing to displaying are arranged, the vapor deposition mask including: a mask sheet provided with a valid portion extending across the plurality of active regions and including a plurality of vapor deposition holes formed to be arranged; and a plurality of hauling sheets configured to support the mask sheet, wherein the valid portion includes a first region and a second region, the first region has a shape corresponding to a shape of each of the plurality of active regions, and is provided for each of the plurality of active regions, and the second region defines a shape of the first region, and overlaps with the plurality of hauling sheets to cause a portion of the plurality of vapor deposition holes to be covered.

In the vapor deposition mask according to a second aspect, the plurality of hauling sheets may extend in a direction perpendicular to an extending direction of the valid portion.

In the vapor deposition mask according to a third aspect, the plurality of hauling sheets may be in contact with a second surface of the mask sheet located on an opposite side to a first surface facing the vapor target substrate.

In the vapor deposition mask according to a fourth aspect, a pitch at which a plurality of vapor deposition holes present in the second region are arranged may be an integral multiple of a pitch at which a plurality of vapor deposition holes present in the first region are arranged.

In the vapor deposition mask according to a fifth aspect, a pitch at which a plurality of vapor deposition holes present in the second region are arranged may be equal to a pitch at which a plurality of vapor deposition holes present in the first region are arranged.

In the vapor deposition mask according to a sixth aspect, a width between the first regions may be an integral multiple of a pitch of the plurality of vapor deposition holes.

In the vapor deposition mask according to a seventh aspect, the valid portion may be provided on all the mask sheet.

In the vapor deposition mask according to an eighth aspect, a region of the valid portion between hauling sheets located at both ends may have a constant width.

In the vapor deposition mask according to a ninth aspect, the mask sheet may include a region having a width gradually increasing outward in a region outside of the region of the valid portion having a constant width.

In the vapor deposition mask according to a tenth aspect, the mask sheet may gradually expand from a width at each of positions including both ends of the valid portion, toward a width at a position including a central portion of the valid portion.

In the vapor deposition mask according to an eleventh aspect, one side of the first region may include a notch protruding from the one side toward an interior direction of the first region, and the plurality of vapor deposition holes in a region located outside of the first region and surrounded by the notch may be covered with each of the plurality of hauling sheets.

A method for manufacturing a vapor deposition mask according to a twelfth aspect provides a method for manufacturing a vapor deposition mask configured to be used to vapor-deposit a vapor-deposition layer on each of pixels of a vapor target substrate provided with a plurality of active regions on which the pixels contributing to displaying are arranged, the method including: a vapor-deposition-hole forming step for forming a plurality of vapor deposition holes in a mask sheet and providing a valid portion extending across a plurality of the active regions; a hauling-sheet attachment step for attaching a plurality of hauling sheets to a mask frame; and a mask-sheet attachment step for attaching the mask sheet to the mask frame to cause the mask sheet to overlap with the plurality of hauling sheets and to be supported by the plurality of hauling sheets, and providing a first region and a second region in the valid portion, wherein the first region is a region having a shape corresponding to a shape of each of the plurality of active regions, and being provided for each of the plurality of active regions, and the second region is a region defining a shape of the first region, and overlapping with the plurality of hauling sheets to cause a portion of the plurality of vapor deposition holes to be covered.

In the method for manufacturing a vapor deposition mask according to a thirteenth aspect, a region of the valid portion between hauling sheets located at both ends may have a constant width.

The disclosure is not limited to each of the embodiments described above, and various modifications may be made within the scope of the claims. Embodiments obtained by appropriately combining technical approaches disclosed in each of the different embodiments also fall within the technical scope of the disclosure. Moreover, novel technical features can be formed by combining the technical approaches disclosed in the embodiments.

REFERENCE SIGNS LIST