Patent ID: 12234540

It should be understood that the dimensions of the various parts shown in the accompanying drawings are not drawn according to the actual scale. In addition, the same or similar reference signs are used to denote the same or similar components.

DETAILED DESCRIPTION

Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended as a limitation to the present disclosure, its application or use. The present disclosure may be implemented in many different forms, which are not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete, and fully convey the scope of the present disclosure to those skilled in the art. It should be noticed that: relative arrangement of components and steps, material composition, numerical expressions, and numerical values set forth in these embodiments, unless specifically stated otherwise, should be explained as merely illustrative, and not as a limitation.

The words “first”, “second”, and similar words used in the present disclosure do not denote any order, quantity or importance, but merely serve to distinguish different parts. Such similar words as “comprising” or “including” mean that the element preceding the word encompasses the elements enumerated after the word, and does not exclude the possibility of encompassing other elements as well. The terms “up”, “down”, “left”, “right”, or the like are used only to represent a relative positional relationship, and the relative positional relationship may be changed correspondingly if the absolute position of the described object changes.

In the present disclosure, when it is described that a particular device is located between the first device and the second device, there may be an intermediate device between the particular device and the first device or the second device, and alternatively, there may be no intermediate device. When it is described that a particular device is connected to other devices, the particular device may be directly connected to said other devices without an intermediate device, and alternatively, may not be directly connected to said other devices but with an intermediate device.

All the terms (including technical and scientific terms) used in the present disclosure have the same meanings as understood by those skilled in the art of the present disclosure unless otherwise defined. It should also be understood that terms as defined in general dictionaries, unless explicitly defined herein, should be interpreted as having meanings that are consistent with their meanings in the context of the relevant art, and not to be interpreted in an idealized or extremely formalized sense.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, these techniques, methods, and apparatuses should be considered as part of this specification.

During the OLED (Organic light-emitting diode) panel production process, the mask device for vacuum evaporation is a component of vital importance. The quality of the mask device directly affects the manufacturing cost of the production and the quality of the product. In some related technologies, the mask device for evaporation may include a frame, a support mask, and a fine metal mask, wherein the support mask and the fine metal mask are sequentially welded on the frame. When the opening area of the support mask exceeds a certain offset from a design position, the organic light-emitting materials evaporated through the adjacent supporting metal mask and fine metal mask may interfere with each other in color during light emission, thereby resulting in undesirable conditions such as color mixture of the display device during display.

During the manufacturing of the irregular screen, there is a need to use a support mask with an irregular opening area, which support mask is required to be welded to the frame after stretching so as to subsequently weld the fine metal mask. Under the action of a stretching force, when the support mask as limited by an irregular shape and a low manufacturing accuracy is stretched and welded to the frame, the irregular opening area in the irregular mask is easily to be offset from a design position, so that the evaporation precision is reduced, thereby resulting in undesirable conditions such as color mixture of the manufactured display device during display, and even affecting the product yield of the entire batch.

In view of this, the embodiments of the present disclosure provide a mask, a mask device, and a mask design method, which can reduce the uneven deformation of the opening area of the mask when the mask is stretched.

FIG.1is a schematic flowchart of an embodiment of a mask design method according to the present disclosure.FIG.2is an example of a layout design drawing of a mask to be optimized used in an embodiment of a mask design method according to the present disclosure.FIG.3is a schematic view of modeling an upper left ¼ part (within a dashed frame) and performing stretching simulation of an example of a layout design drawing ofFIG.2.FIG.4is a deformation cloud chart of a first rib between two adjacent opening areas in a stretching direction after stretching simulation based on the mask model corresponding toFIG.3.

Referring toFIG.1, in some embodiments, the mask design method includes steps S100to S300.

In step S100, at least part selected of the layout design drawing of the mask to be optimized is modeled to obtain a mask model. Referring to an example of a layout design drawing shown inFIG.2, in the layout design drawing, the mask20to be optimized may include a pattern area and a second rib23located at an edge of the pattern area. The pattern area includes a plurality of openings21, wherein adjacent openings21are spaced apart by a first rib22.

InFIG.2, a plurality of openings21may be arranged at intervals along the x-axis and the y-axis perpendicular to each other respectively, so as to form an array of openings. The size and shape of the opening21may be designed as required. For the support mask, the shape and size of the opening21may be consistent with the actual display area of the display device. For example, for a mobile terminal with a sensor element in the top area of the display screen, its opening may be designed to have an inwardly convex portion adapted to the shape of the display screen, such that the convex portion corresponds to an area where the sensor element is arranged.

When the design of the mask is optimized, the overall layout design drawing of the mask to be optimized may be modeled first to obtain the mask model. In some embodiments, in the case where the layout design drawing is relatively symmetrical, apart of the layout design drawing may be selected for modeling to obtain a mask model, thereby reducing the amount of data during model calculation and improving the efficiency.

InFIG.2, the plurality of openings21have the same or substantially the same shape and size, and are distributed at equal intervals along the x-axis and the y-axis. Correspondingly, in some embodiments, during the modeling process, ¼ part of the layout design drawing (see the portion selected by the dashed frame inFIG.2) may be selected for modeling. The ¼ part is taken from any corner point of the layout design drawing.

Although the upper and lower edges of the opening21are asymmetrical along the y-axis, since the asymmetrical size accounts for a very small proportion of the overall size of the opening21, there is a relatively limited influence. In this way, the layout design drawing selected by the dashed frame may be mirrored once or twice relative to a centerline parallel to the x-axis and a centerline parallel to the y-axis so as to approximately obtain the other ¾ part of the layout design drawing.

In step200, stretching simulation is performed on the established mask model, and a reference opening in the mask is determined based on a simulation result. The reference opening here refers to an opening that satisfies the condition that a local relative offset of the side in a first direction exceeds the first preset threshold during stretching simulation.

Referring toFIG.3, the first direction may be defined as a stretching direction during stretching simulation, that is, the y-axis direction inFIG.2. The stretching force F during stretching simulation may act on each pin24outside the edge of the mask inFIG.2, and the direction of the stretching force F is a stretching direction, which is consistent with the y-axis direction.

Taking the opening21inFIG.3as an example, the stretching direction is the y-axis direction. In this direction, if the local relative offset of the upper or lower side of the opening21exceeds the first preset threshold, the opening21may be defined as a reference opening. The local relative offset may be a local offset of the side itself relative to other parts during stretching simulation. The first preset threshold may be set according to factors such as the material of the mask and the position of the opening area.

When stretching simulation is performed on the mask model, since the opening21has a non-straight side or asymmetrical upper and lower sides, there is a difference in local relative offsets of different parts of the sides. InFIG.4, the upper side of the opening21has a trapezoidal recess section that is inwardly recessed. Referring to the deformation cloud map of the first rib between adjacent openings displayed in different gray scales in a stretching direction inFIG.4, the deformation of the part A of the first rib corresponding to the trapezoidal recess section may reach 1.167 e−1mm to 1.333 e−1mm, and the deformation of the part B corresponding to a relatively flat part on both sides of the trapezoidal recess section is 1.000 e−1mm to 1.167 e−1mm, which is less than the deformation of the part A. Thus, it may be seen that the stress is relatively concentrated in a part of the first rib corresponding to the trapezoidal recess section.

FIG.5is a schematic view of providing a cutout in the second rib according to an embodiment of a method for designing and optimizing of a mask of the present disclosure.FIG.6is an enlarged view of the area selected by the elliptical frame inFIG.5.FIG.7is a schematic view of the comparison of the deformation curves of the first rib during the stretching simulation of the mask model before and after optimization.

Referring toFIGS.5-7, the stress concentration causes the deformation of the opening21. In order to suppress the degree of such deformation, in step S300, a cutout25may be provided in the second rib23in the layout design drawing. The extending lines of the side of the reference opening extending towards the second rib23along a first direction and intersects with the second rib23so that a first area E1is obtained, wherein the cutout25is located at least within the first area E1.

In some embodiments, the cutout may be optionally a through hole penetrating in a normal direction of the mask. The cutout may be formed by etching, and made into a through hole so that it is possible to reduce the difficulty of etching, and reduce the complexity of the process. Moreover, it is also possible to reduce a local warpage of the mask in a normal direction of the mask and reduce the risk of foreign matter produced by friction between a warped portion and the substrate to a certain extent. In other embodiments, the cutout may also be a blind hole.

Referring toFIGS.5and6, a cutout25may be provided in the second rib23corresponding to the opening21that has been defined as a reference opening in the layout design drawing, so as to obtain a layout design drawing of a mask20′ that has been optimized.

The step of providing a cutout in the second rib23may include: providing a plurality of cutouts25in the first area E1, such that the plurality of cutouts are arranged at intervals along a first direction. Referring toFIG.6, each reference opening area may be provided with four cutouts25in the first area E1along the y-axis direction. The number and spacing of the cutouts25may be adjusted and optimized several times based on simulation results.

InFIG.6, the upper side of the opening21is a non-straight side26, and both sides of the non-straight side26respectively have two straight sections26a. A recess section26bthat is inwardly recessed in the shape of a polyline is formed in the middle of the non-straight side26, such that both ends of the recess section26bare connected to the two straight sections26arespectively. Referring toFIG.7, the horizontal axis inFIG.7represents different distances from one end to the other end of the side of the opening area, and the vertical axis represents an amount of deformation (that is, an offset) compared to a state in which stretching simulation is not performed. The simulation results of the mask without a cutout25provided in the second rib (before optimization) and the mask provided with a cutout25(after optimization) are compared. It may be seen fromFIG.7that the deformation amount curve D1of the first rib before optimization is relatively close to the deformation amount curve D2of the first rib after optimization, and there is an apparent difference between the deformation amounts of the recess section26b. The deformation amount of the recess section26bin the middle of the first rib before optimization may reach more than 0.122 mm, and the deformation amount of the recess section26bof the optimized first rib is reduced to 0.12 mm.

In the above-described embodiment, modeling and stretching simulation are performed on the layout design drawing of the mask to be optimized to determine a reference opening with a large local offset in a stretched state and provide a cutout in the first area of the second rib corresponding to a projection of the reference opening, so that it is possible to improve a balanced stress distribution condition of the mask when actually stretched, thereby reducing the uneven deformation of the opening of the mask when the mask is stretched, and further reducing the offset degree of the opening from a design position and improving the evaporation accuracy.

For a mask in which the opening is mirror-symmetrical to itself in a second direction (for example, the x-axis direction) perpendicular to the first direction, referring toFIG.6, in some embodiments, when a cutout is provided in the second rib, the cutout25may alternatively be made symmetrical relative to a centerline25aof the recess section26b, and the centerline25aof the recess section is parallel to the first direction. In this way, it is possible to allow a more balanced stress distribution of the mask when stretched. In addition, inFIGS.5and6, the shape of the cutout is rectangular. In other embodiments, the shape of the cutout may also be other shape, such as a crescent shape or an oval shape.

FIGS.8and9are schematic views of the warping deformation of the frame when the mask before and after the optimization is stretched and welded to the frame.

Referring toFIG.8, for the support mask, in order to reduce the sagging degree arising from high temperature and gravity, there is a need to weld the support mask to the frame in a stretched state. After the welding is completed, a tensile force of the support mask is exerted on the frame. On one hand, the frame may resist the elastic restoration of the mask after a tensile force is released; on the other hand, the frame is deformed and warped under the tension of the support mask. It may be seen fromFIG.8that the frame welded with the support mask before optimization may be warped significantly.

For the optimized mask, the rigidity of the second rib of the mask may be reduced by providing a cutout in the second rib, so that each part of the mask may reach a design position under the effect of a smaller tensile force, thereby reducing a tensile force that stretches the mask, so as to correspondingly reduce a tensile force of the mask on the frame, thereby lessening the warpage of the frame after the welding is completed and facilitating further improving the evaporation accuracy. It may be seen fromFIG.9that after the optimized mask is stretched and welded to the frame, the degree of warpage of the frame is lessened as compared toFIG.8.

FIG.10is a schematic flowchart of another embodiment of a design method of a mask according to the present disclosure.FIG.11is a schematic view of performing modeling and stretching simulation of part of another example of a layout design drawing of a mask.FIG.12is an enlarged view of the area selected by the elliptical frame inFIG.11.

Referring toFIG.10, compared with the embodiment inFIG.1, in some embodiments, the design method further include step S400. The step S400may be performed before the step S300, after the step S300, or simultaneously with the step S300. In step S400, if it is determined that the local relative offset exceeds a second preset threshold based on a simulation result, and the second preset threshold is greater than the first preset threshold, a cutout27will also be provided in the first rib in the layout design drawing. The extending lines of the two first straight sides of the reference opening extending toward the first rib intersect with the first rib to obtain a second area E2. The cutout27is located at least within the second area E2. In some embodiments, the cutout may be a through hole penetrating in a normal direction of the mask. In other embodiments, the cutout may also be a blind hole.

For example, the first preset threshold of the local relative offset may be set to 0.006 mm, and the second preset threshold is 0.008 mm. When a simulation result after stretching simulation shows a local relative offset exceeding 0.006 mm, and less than or equal to 0.008 mm, the corresponding opening may be determined as a reference opening, and a cutout is provided in the corresponding second rib. If there is a local relative offset exceeding 0.008 mm, not only a cutout is provided in the corresponding second rib, but also a cutout is provided in the corresponding first rib. In some embodiments, if a simulation result of the mask shows that the local relative offsets of some openings conform to different thresholds, a cutout may be selectively provided according to the local relative offsets.

Referring toFIGS.11and12, in some embodiments, the upper side of the opening21′ of the selected ¼ mask20″ is a non-straight side26′, wherein both sides of the non-straight side26′ have two straight sections26a′ respectively. A recess section26b′ that is inwardly recessed in the shape of a circular arc is formed in the middle of the non-straight side26′, and both ends of the recess section26b′ are respectively connected to the two straight sections26a′. The recess section26b′ in the shape of a circular arc is more easily to cause stress concentration in the first rib22than the recess section26bin a polyline shape inFIG.6, thereby forming a more apparent local relative offset. In order to reduce the local relative offset, in addition to providing a cutout in the second rib23, a cutout may also be provided in the first rib22. The shape of the cutout may be a rectangular shape, a crescent shape or a semi-circular shape.

For a mask with a narrow first rib22between adjacent openings21′, it is optional that a single cutout27may be provided in the second area of the first rib connected with the reference opening in the layout design drawing. On one hand, the single cutout27may cooperate with the cutout25′ in the second rib22to improve a balanced stress distribution condition of the mask when actually stretched, and on the other hand, it is also possible to avoid excessively weakening the rigidity of the first rib22, so as to avoid a significant deformation or warping when the mask is stretched.

InFIGS.11and12, the second rib23may be provided with a cutout25′ in a crescent shape. The crescent shape refers to an enclosed shape with two circular arc edges, such that a raised direction of the two circular arc edges of the crescent shape is opposite to a recessed direction of the recess section. In other words, the distance from both ends of the crescent-shaped cutout to a straight section of the non-straight side is less than the distance from a middle part of the crescent-shaped cutout to the straight section. In other embodiments, the second rib23may also be provided with a cutout25in a rectangular shape as shown inFIG.6.

In each embodiment of the above-described mask design method, if the mask model is modeled from part of the layout design drawing, other parts of the layout design drawing that have not been selected will be correspondingly optimized according to an optimization manner of the selected part. With reference toFIG.2, since it is mentioned above that the selected part of the layout design drawing (that is, the ¼ part selected by the dashed frame) may be mirrored once or twice relative to a centerline parallel to the x-axis and a centerline parallel to the y-axis to approximately obtain the other parts that have not been selected, when a local layout design drawing after optimization inFIG.5is obtained, the optimization method may be expanded to the entire layout design drawing so as to improve the design optimization efficiency, that is, a cutout25is provided in the second rib along a first direction and the second rib along a direction opposite to the first direction in all the openings21respectively. Similarly, the cutout27provided in the first rib may also be expanded from the selected part to the unselected parts of the layout design.

FIG.13is a schematic plan view of an embodiment of the mask device according to the present disclosure.

Referring toFIG.13, in some embodiments, the mask device includes: a frame10and a mask20′. The mask20′ may be manufactured using a layout design drawing of the mask obtained after optimization by the design method of the present disclosure. The mask20′ is disposed on the frame10, for example, a plurality of pins24outside the edge of the mask20′ are welded to the upper surface of the frame10in a state when the mask20′ is stretched.

In other embodiments, the mask device may also include a fine mask. The fine mask is disposed on the frame, and the mask20′ may serve as a support mask to support the fine mask, that is, the mask is a support mask. In addition to supporting the fine mask20′, the mask20′ may also shield some areas of the fine mask, so that the evaporation material can be deposited on a corresponding display area in the substrate.

Referring toFIGS.5,6and13, in some embodiments, the mask includes: a pattern area and a second rib23located at an edge of the pattern area. The pattern area includes a plurality of openings21, wherein adjacent openings21are spaced apart by a first rib22. At least one of the openings21has a non-straight side26, two first straight sides21aintersecting with the non-straight side26, and a second straight side21bthat is opposite to the non-straight side26and intersects with the first straight side21a.

The second rib23is provided with a cutout25for compensating for tensile deformation of the non-straight side26. The extending lines of the two first straight sides21aextending towards the second rib23along a first direction intersect with the second rib23to obtain a first area E1. The cutout is located at least within the first area E1. The first direction is parallel to the first straight side21a, and the second direction perpendicular to the first direction is parallel to the second straight side21b. Here, the first direction may be a stretching direction during stretching simulation in the embodiments of the mask design method, that is, the y-axis direction inFIG.13, and the second direction may be the x-axis direction inFIG.13.

In some embodiments, it is optional that the cutout25may be a through hole penetrating in a normal direction of the mask. In other embodiments, the cutout25may also be a blind hole. The cutout25in the second rib23may improve a balanced stress distribution condition of the mask when actually stretched, thereby reducing the uneven deformation of the pattern area of the mask when the mask is stretched. In addition, the rigidity of the second rib of the mask may also be reduced, so that each part of the mask may reach a design position under the action of a smaller tensile force, so as to reduce a tensile force that stretches the mask and correspondingly reduce a tensile force of the mask on the frame, thereby further lessening the warpage of the frame after the welding is completed and facilitating improving the evaporation accuracy.

InFIG.13, a plurality of openings21may be distributed in an array. All the openings21(in other embodiments, part of the openings21) in each column of openings21have a non-straight side26extending substantially along a second direction. The second direction is parallel to a row direction of the array, and the cutout is provided within the first area E1of the second rib23corresponding to each column of openings21.

The plurality of openings21have the same shape and size, and the first straight sides21aof the plurality of openings21are all parallel to the first direction, where the first direction is parallel to a column direction of the array, and the cutouts provided in the first area E1of the second rib23corresponding to each column of openings21have the same number, shape and size. In this way, it is possible to allow a more balanced stress at each position when the mask is actually stretched, and reduce the degree of uneven deformation of the opening of the mask.

According to the shape of the display area of the display device to be manufactured, in some embodiments, the length of the non-straight side26in the second direction may be made less than the length of each of the first straight sides21a, and equal to the length of the second straight side21b.

Referring toFIG.6, in some embodiments, the non-straight side26includes two straight sections26aand a recess section26bthat is recessed toward the inner side of the opening21relative to the straight section26a. Both ends of the recess section26bare respectively connected to the two straight sections26a, and the cutout25is symmetrical relative to a centerline25aof the recess section26b, where the centerline25aof the recess section26bis parallel to the first direction. By making the cutout25symmetrical relative to a centerline25aof the recess section26b, it is possible that the cutout25can more effectively reduce a local relative offset of the recess section26b.

According to the shape of a display area of the display device to be manufactured, in some embodiments, the recess section26bmay be located at a middle position of the non-straight side26, and the cutout25is also symmetrical relative to a centerline of the non-straight side26accordingly. In other embodiments, the cutout25may be straight, and its extending direction is substantially parallel to the second direction. For example, the shape of the cutout is rectangular, and parallel to the second direction.

InFIG.6, the recess section26bmay be in the shape of a polyline, and in other embodiments, for example inFIG.12, the recess section26b′ may be in the shape of a circular arc. When a cutout is provided in the second rib23of the mask, it is optional that the length of the cutout25in the second rib23in the second direction may be less than the length of the non-straight side26in the second direction, and greater than the length of the recess section26bin the second direction. At this time, the cutout25does not intersect with the extending line of the tensile force F, so as to avoid apparent deformation of the cutout25during stretching, and the cutout25that is longer than the recess section26bcan more effectively improve the influence on the local relative offset of the recess section26b. Specifically, the length of the cutout located in the second rib23in the second direction may be 40 mm to 60 mm, and correspondingly, the length of the recess section26bin the second direction is 3 mm to 35 mm.

In order to more effectively improve the local relative offset of the opening and reduce the rigidity of the second rib, referring toFIG.6, in some embodiments, the cutouts in the second rib23corresponding to respective column of openings21have at least two cutouts arranged at intervals in the first direction, for example, four cutouts25inFIG.6. In some embodiments, the width of the second rib23in the first direction may be 20 mm to 70 mm, the width of the first rib22in the first direction may be 10 mm to 15 mm, and the width of the recess section26bin the first direction is 0.5 mm to 8 mm.

Correspondingly, the width and center-to-center distance of each cutout in the first direction may be determined based on the simulation data and the position of a solid material on the fine mask. Specifically, the width of each cutout in the first direction may be set to be 0.6 mm to 1 mm, and the center-to-center distance of adjacent cutouts in the first direction may be set to be 4 mm to 8 mm.

FIG.14is a schematic plan view of another embodiment of the mask device according to the present disclosure.

Compared with the embodiment shown inFIG.13, in the mask20″ shown inFIG.14, the shape of the cutout may also be a crescent shape, and a raised direction of the two arc edges of the crescent shape is opposite to a recessed direction of the recess section. In other embodiments, the plurality of cutouts25provided in the first area E1of the second rib23may include cutouts in two or more different shapes.

InFIG.12, the non-straight side26′ has a recess section26b′ in a circular arc shape. Since its length in the second direction is shorter than the lengths of the straight sections26a′ at both ends, its local relative offset is greater than the local relative offset of the recess section26bin the shape of a polyline inFIG.6. Correspondingly, referring toFIGS.12-14, the cutout27may also be provided in the first rib22connected with the non-straight side26. The extending lines of the two first straight sides21aextending towards the first rib22along the first direction intersect with the first rib22to form a second area E2, wherein the cutout27is located at least within the second area E2. The relevant size and position of the cutout27may refer to the aforementioned cutout25located in the first area E1. With the cutout27, it is possible to effectively improve the local relative offset of the recess section26b′.

In order to avoid excessively weakening the rigidity of the first rib22, it is optional that the number of the cutouts provided in each of the first ribs22connected with the non-straight side2may be one.

The above-described embodiments of the mask may be applied to a mask device, and the positions of the cutouts provided in the first and second ribs of the mask correspond to a region of a solid material of the fine mask, so as to prevent leakage of redundant evaporation material. The support mask and the fine mask may be both made of metal.

Hereto, various embodiments of the present disclosure have been described in detail. Some details well known in the art are not described to avoid obscuring the concept of the present disclosure. According to the above description, those skilled in the art would fully know how to implement the technical solutions disclosed herein.

Although some specific embodiments of the present disclosure have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for the purpose of illustration and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that modifications to the above embodiments and equivalently substitution of part of the technical features may be made without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.