Stretchable display device and method of manufacturing stretchable display device

Abstract

A stretchable display device (1) is provided with a stretch substrate (11), a plurality of support substrates (12) each having pixels (2), a first stretch wiring (21) connecting the pixels together, a first stretch dummy wiring (31) connecting the support substrates together, and stretch measurement units (42, 43) for measuring a stretch ratio of the first stretch dummy wiring and estimating a stretch ratio of the first stretch wiring.

Description

Stretchable display device and method for manufacturing stretchable display device

[0001] The present disclosure relates to a stretchable display device that is stretchable in an in-plane direction, and a method for manufacturing the stretchable display device.

[0002] Patent Document 1 discloses a stretchable display device that can stretch in the in-plane direction of the substrates by providing stretchable connection wiring between a plurality of substrates, each of which includes sub-pixels.

[0003] US Patent Application Publication No. 2021 / 0027671

[0004] In the stretchable display device described in Patent Document 1, when an external force of a predetermined magnitude or greater is applied in the stretching direction of the substrate, the connecting wires may break or may not be able to restore their shape. In the stretchable display device described in Patent Document 1, providing a separate device for measuring the external force applied to the substrate would increase the complexity and cost of the stretchable display device.

[0005] A stretchable display device according to one aspect of the present disclosure includes a stretchable base that is stretchable in a first direction among in-plane directions; a plurality of support bases formed on the stretchable base, each having a pixel; first stretchable wiring that connects the pixels of at least two of the support bases and is stretchable in the first direction; first stretchable dummy wiring that connects the support bases on which the pixels to which the first stretchable wiring are connected are formed and is stretchable in the first direction; and an expansion / contraction measurement unit that measures an expansion rate of the first stretchable dummy wiring in the first direction and estimates an expansion rate of the first stretchable wiring in the first direction.

[0006] A manufacturing method of a stretchable display device according to one aspect of the present disclosure includes preparing a stretchable base that is stretchable in a first direction among in-plane directions; forming a plurality of support bases, each having pixels, on the stretchable base; forming first stretchable wires that connect the pixels of at least two of the support bases and are stretchable in the first direction; forming first stretchable dummy wires that connect the support bases on which the pixels to which the first stretchable wires are connected are formed and are stretchable in the first direction; and forming an expansion / contraction measuring unit that measures the expansion rate of the first stretchable dummy wires in the first direction and estimates the expansion rate of the first stretchable wires in the first direction.

[0007] The present invention reduces deformation of connecting wiring while reducing the complexity or cost increase of a stretchable display device.

[0008] FIG. 1 is an enlarged plan view of a portion of a display device according to an embodiment. FIG. 2 is a schematic diagram of a display device according to an embodiment. FIG. 3 is a schematic side cross-sectional view of a display device according to an embodiment. FIG. 4 is a schematic diagram showing an example of a side cross-section of a first expandable wire and a first expandable dummy wire according to an embodiment. FIG. 5 is an enlarged plan view of a portion of a display device for showing deformation of the expandable wire and the expandable dummy wire accompanying extension of an expandable base of the display device according to an embodiment. FIG. 6 is a graph showing the relationship between the strain of the first expandable dummy wire measured by a strain gauge according to an embodiment and the measured value of the stress applied to the first expandable dummy wire. FIG. 7 is a flowchart showing a method for manufacturing a display device according to an embodiment.

[0009] [Embodiment 1] <Outline of Display Device> Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. FIG. 2 is a schematic diagram of a display device 1 according to this embodiment. The display device 1 is a stretchable display device that can expand and contract in at least one in-plane direction. The display device 1 includes a display unit DA including a plurality of pixels 2, and a frame region NA that is positioned around the display unit DA in a plan view and includes a driver circuit DR that drives the plurality of pixels 2. Each of the plurality of pixels 2 includes a light-emitting element EL and a pixel circuit PC that drives the light-emitting element EL. The display device 1 displays an image on the display unit DA by controlling light emission from each of the plurality of light-emitting elements EL formed in the display unit DA via the driver circuit DR and the pixel circuit PC.

[0010] The light-emitting elements EL are, for example, field injection light-emitting elements, and include, as light-emitting materials, for example, organic light-emitting materials, organic phosphorescent materials, quantum dot materials, etc. The pixel circuits PC include, for example, transistors such as TFTs, and individually drive each light-emitting element EL based on a signal from the driver circuit DR.

[0011] The structure of the display device 1, particularly the structure of the display device 1 in the display unit DA, will be described in more detail with reference to Fig. 1. Fig. 1 is an enlarged plan view of the display device 1 according to an embodiment of the present disclosure, and in particular is a plan view showing an enlarged view of some of the multiple pixels 2 of the display device 1 and part of the frame region NA.

[0012] <Stretchable Base and Support Base> As shown in FIG. 1 , the display device 1 includes a stretchable base 11 at a position overlapping at least the display unit in a planar view. One of the in-plane directions of the stretchable base 11, for example, the left-right direction as viewed in FIG. 1 is defined as a first direction D1, and the up-down direction as viewed in FIG. 1 , or in other words, the direction perpendicular to the first direction D1, is defined as a second direction D2. In this case, the stretchable base 11 according to this embodiment is stretchable within a predetermined range in at least the first direction D1. In particular, the stretchable base 11 is stretchable within a predetermined range in each of the first direction D1 and the second direction D2. The stretchable base 11 may include a material, such as a resin, that is elastic and capable of restoring its shape. The stretchable base 11 may also overlap the frame region NA in a planar view. FIG. 1 illustrates the display device 1 when no external force that stretches the stretchable base 11 is applied to the stretchable base 11 in either the first direction D1 or the second direction D2.

[0013] The display device 1 further includes a plurality of support bases 12 formed in a region of the stretchable base 11 that overlaps with the display unit DA in a plan view. For example, the display device 1 includes a plurality of support bases 12, and the plurality of support bases 12 are arranged along each of a first direction D1 and a second direction D2. Each of the support bases 12 has a pixel 2. Therefore, in the display device 1, the pixels 2 are arranged along each of the first direction D1 and the second direction D2. The support base 12 may include a material that is elastic and capable of restoring its shape, such as a resin, and may include, for example, a material that is more rigid than the stretchable base 11.

[0014] The distance between the multiple support bases 12 formed on the stretchable base 11 varies as the stretchable base 11 expands and contracts. For example, the distance along the first direction D1 between two adjacent support bases 12 in the first direction D1 increases as the stretchable base 11 expands in the first direction D1. Note that the support base 12 itself may not deform regardless of the expansion and contraction of the stretchable base 11, or the support base 12 itself may deform in response to the expansion and contraction of the stretchable base 11.

[0015] The stretchable base 11 and the support base 12 on the stretchable base 11 will be described in more detail with reference to Fig. 3. Fig. 3 is a schematic side cross-sectional view of the display device 1, and in particular, a cross-sectional view taken along the arrow A-A shown in Fig. 1. In other words, Fig. 3 shows a side cross-section of the display device 1 in a plan view, which is parallel to the first direction D1, for example, and passes through two support bases 12 and the pixels 2 that each of the two support bases 12 has.

[0016] As shown in Fig. 3, pixels 2 each including a light-emitting element EL and a pixel circuit PC are formed on each of a plurality of support substrates 12 on the stretchable substrate 11. As shown in Fig. 3, the display device 1 may also include a sealing film 6. In this case, the support substrate 12 including the pixels 2 may be sealed on the stretchable substrate 11 by being covered with the sealing film 6 having light transparency. The sealing film 6 may be formed commonly on the stretchable substrate 11 in a planar view. The sealing film 6 may also stretch together with the stretchable substrate 11 in accordance with the stretching of the stretchable substrate 11 in the in-plane direction.

[0017] 1 , the display device 1 includes first elastic wires 21 that connect the pixels 2 of at least two support bases 12. The first elastic wires 21 connect the pixels 2 of the two support bases 12 that are arranged along a first direction D1 in a planar view, for example. The first elastic wires 21 are formed to be elastic within a predetermined range along the first direction D1 by a structure described later.

[0018] Therefore, even when the distance between the two support bases 12 increases as the stretchable base 11 stretches in the first direction D1, the first stretchable wires 21 stretch, and thereby the first stretchable wires 21 maintain the connection between the two pixels 2. Note that when the stretchable base 11 stretches and the first stretchable wires 21 stretch, and then the stretchable base 11 contracts, the first stretchable wires 21 may contract so as to restore their original shape.

[0019] The first elastic wire 21 may connect two pixels 2 to each other and transmit a signal between the two pixels 2. For example, the first elastic wire 21 may supply a current to the light-emitting element EL of at least one of the two connected pixels 2 to cause the light-emitting element EL of the pixel 2 to emit light. The first elastic wire 21 may also supply a signal to the pixel circuit PC of at least one of the two connected pixels 2 to drive the pixel circuit PC of the pixel 2. Furthermore, the first elastic wire 21 may relay the transmission of a signal supplied to a pixel 2 other than the two connected pixels 2.

[0020] <Expandable Dummy Wiring> The display device 1 includes first expandable dummy wirings 31 that connect the support bases 12 on which the pixels 2 to which the first expandable wirings 21 are connected are formed. The first expandable dummy wirings 31 are located, for example, on both sides of one first expandable wiring 21 in the second direction D2. In other words, the display device 1 includes a plurality of first expandable dummy wirings 31 for one first expandable wiring 21. The first expandable dummy wirings 31 are formed to be expandable within a predetermined range along the first direction D1. In particular, both the first expandable wiring 21 and the first expandable dummy wiring 31 extend in the same direction as the first direction D1.

[0021] Therefore, even when the distance between the two support bases 12 increases as the expandable base 11 expands in the first direction D1, the first expandable dummy wiring 31 expands, and thereby the first expandable dummy wiring 31 maintains the connection between the two support bases 12. However, the first expandable dummy wiring 31 does not have to be a wiring that contributes to the light emission of the light-emitting element EL and the driving of the pixel circuit PC.

[0022] <Specific Example of Stretchable Wiring> An example of the specific configuration of the first stretchable wire 21 and the first stretchable dummy wire 31 will be described with reference to Fig. 4. Fig. 4 is a schematic diagram showing an example of a side cross section of the first stretchable wire 21 and the first stretchable dummy wire 31. All of the schematic diagrams shown in Fig. 4 are cross sections taken along the arrows B-B shown in Fig. 1. In other words, Fig. 4 shows, in a plan view, one first stretchable wire 21 and two first stretchable dummy wires 31 that are parallel to the second direction D2 and are formed on both sides of the first stretchable wire 21 in the second direction D2, of the display device 1.

[0023] 4, the first expandable wire 21 may be a substantially cylindrical wire containing a conductive material. In this case, the first expandable dummy wire 31 may have a conductive portion 71 that has the same shape as the first expandable wire 21 and contains the same material as the first expandable wire 21. In this case, the conductive portion 71 is expandable in the first direction D1 together with the first expandable wire 21.

[0024] Furthermore, the first expandable dummy wire 31 may have a strain gauge 72 covering at least a portion of the outer surface of the conductive portion 71, for example, the upper half of the outer surface of the conductive portion 71 as shown in schematic diagram 401. The strain gauge 72 expands and contracts in the first direction D1 together with the conductive portion 71. In particular, the electrical resistance of the strain gauge 72 changes as the strain gauge 72 expands and contracts in the first direction D1. For this reason, the strain gauge 72 can be used to calculate the expansion rate of the first expandable dummy wire 31 by a method described below. By having the strain gauge 72 cover only the upper half of the outer surface of the conductive portion 71 as shown in schematic diagram 401, the first expandable dummy wire 31 can be formed more simply.

[0025] The shapes of the first expandable wire 21 and the first expandable dummy wire 31 are not limited to the example shown in schematic diagram 401. For example, as shown in schematic diagram 402, the first expandable dummy wire 31 may have a strain gauge 72 formed in a position covering the entire outer surface of the substantially cylindrical conductive portion 71. This makes the change in electrical resistance of the strain gauge 72 more sensitive as the conductive portion 71 expands or contracts, and the strain gauge 72 enables more accurate calculation of the expansion rate of the first expandable dummy wire 31. Furthermore, in this embodiment, an example has been described in which the first expandable dummy wire 31 includes the conductive portion 71 and the strain gauge 72, but this is not limited to this. For example, the first expandable dummy wire 31 may include a member having low conductivity or insulation and the strain gauge 72 located on the member, as long as it is possible to measure the change in electrical resistance of the strain gauge 72 as it expands or contracts.

[0026] Furthermore, as shown in the schematic diagram 403, the first expandable wire 21 may have a flat plate shape, and in this case, the conductive portion 71 of the first expandable dummy wire 31 may also have a flat plate shape. In this case, the strain gauge 72 may be formed on the upper surface of the conductive portion 71. The first expandable wire 21 and the first expandable dummy wire 31 shown in the schematic diagram 403 can be formed even more simply by depositing and patterning a conductive material.

[0027] The first expandable wire 21 and the first expandable dummy wire 31 may contain the same material, or may contain different materials from the first expandable wire 21 and the first expandable dummy wire 31. In this case, for example, the Young's modulus of the first expandable dummy wire 31 may be larger than the Young's modulus of the first expandable wire 21. This makes it possible to make the tension at which the first expandable wire 21 breaks larger than the tension at which the first expandable dummy wire 31 breaks, and to reduce the chance of the first expandable wire 21 breaking before the first expandable dummy wire 31 breaks.

[0028] 1 , the display device 1 may include a current measuring unit 41 on the support base 12 that applies a current to the first expandable dummy wiring 31 and measures the current flowing through the first expandable dummy wiring 31. The current measuring unit 41 may be connected to both ends of one first expandable dummy wiring 31.

[0029] The display device 1 may include an IC 42 and an expansion / contraction measuring unit 43 in the frame region NA. For example, the display device 1 may include a flexible printed circuit board FC in the frame region NA, which mediates the transmission of signals from a power supply unit (not shown) or the like to each driver circuit DR. In this case, the IC 42 may be formed on the flexible printed circuit board FC. The expansion / contraction measuring unit 43 may also be formed on the frame region NA, particularly on the expandable base 11 in the frame region NA. The display device 1 may include at least one of the IC 42 and the expansion / contraction measuring unit 43; in other words, it does not have to include both the IC 42 and the expansion / contraction measuring unit 43.

[0030] The IC 42 and the expansion / contraction measuring unit 43 each measure the expansion / contraction rate of the first expandable dummy wiring 31 in the first direction D1 by a method described later, and estimate the expansion / contraction rate of the first expandable wiring 21 in the first direction D1. In other words, at least a part of the expansion / contraction measuring unit that measures the expansion / contraction rate of the first expandable dummy wiring 31 in the first direction D1 may be formed in the IC 42.

[0031] In addition, the "expansion / contraction ratio of the wiring" in the present disclosure may refer to the ratio of extension of the wiring based on the wiring length in a state where no external force is applied to the wiring along the extension direction of the wiring. Alternatively, the "expansion / contraction ratio of the wiring" in the present disclosure may refer to the ratio of the length of the wiring in a predetermined direction among the in-plane directions of the expandable base 11 to the wiring length of the wiring.

[0032] Including at least a part of the expansion / contraction measuring unit in the IC 42 makes it possible to integrate the functions of the expansion / contraction measuring unit in the IC 42, further simplifying the configuration of the expansion / contraction measuring unit. On the other hand, providing the display device 1 with the expansion / contraction measuring unit 43 in the frame region NA makes it possible to form the expansion / contraction measuring unit 43 in a position close to the first expansion / contraction dummy wiring 31. As a result, the expansion / contraction measuring unit 43 further shortens or simplifies the routing wiring 5, simplifying the configuration of the display device 1.

[0033] 1, the IC 42 and the expansion / contraction measuring unit 43 may be connected to the current measuring unit 41. As a result, the IC 42 and the expansion / contraction measuring unit 43 may measure the current value of the current flowing through each first expansion / contraction dummy wiring 31 or the electrical resistance of the strain gauge 72 of each first expansion / contraction dummy wiring 31 based on a signal from each current measuring unit 41. In other words, the drawing wiring 5 may connect each first expansion / contraction dummy wiring 31 to each of the IC 42 and the expansion / contraction measuring unit 43 via each current measuring unit 41, and may be drawn out to the frame region NA.

[0034] By routing the wiring 5 connected to each of the first expansion / contract dummy wirings 31 to the IC 42 and the expansion / contract measurement unit 43 located in the frame area NA, it is not necessary to form the IC 42 and the expansion / contract measurement unit 43 in the display area DA. Therefore, the wiring 5 can secure a larger area for forming the pixels 2 in the display area DA.

[0035] Furthermore, the display device 1 may include a warning unit 44, for example, in the frame region NA. The warning unit 44 issues a warning to the user when the elongation rate of the first expandable dummy wiring 31 measured by a method described below becomes equal to or greater than a predetermined value. The warning unit 44 may include, for example, a lamp such as an LED that issues the warning by lighting up or the like, or a speaker that issues the warning by sound or the like.

[0036] <Expansion and contraction of wiring> The expansion and contraction of the first expandable wiring 21 and the first expandable dummy wiring 31 in the first direction D1 will be described with reference to Fig. 5. Fig. 5 is an enlarged plan view of a part of the display unit DA of the display device 1, and particularly shows two support bases 12 arranged in the first direction D1, the pixels 2 on the support bases 12, and the first expandable wiring 21 and first expandable dummy wiring 31 formed between the support bases 12.

[0037] For example, as shown in the plan view 501 of Fig. 5, the first expandable wires 21 and the first expandable dummy wires 31 both extend along the first direction D1. Also, as shown in the plan view 501 of Fig. 5, for example, in a state where no external force is applied in a direction extending along the first direction D1 between two support bases 12, the first expandable wires 21 and the first expandable dummy wires 31 meander in the second direction D2.

[0038] In the above state, for example, assume that an external force is applied between the two support bases 12 in a direction that causes the wires to stretch along the first direction D1. In this case, the first expandable wires 21 and the first expandable dummy wires 31 each stretch along the first direction D1 by deforming so as to reduce the width of the meandering, as shown in the plan view 502. Therefore, the first expandable wires 21 and the first expandable dummy wires 31 stretch along the first direction D1 while preventing changes that affect conductivity, such as breakage or a reduction in thickness.

[0039] The first expandable wires 21 and the first expandable dummy wires 31 have predetermined elasticity and shape memory properties. Therefore, as the external force decreases, the first expandable wires 21 and the first expandable dummy wires 31 contract along the first direction D1. When the external force is removed, the first expandable wires 21 and the first expandable dummy wires 31 may contract along the first direction D1 to the shape shown in the plan view 501, for example.

[0040] In other words, at least the first expandable dummy wire 31 may include a shape-memory material. The shape-memory material may enable the first expandable dummy wire 31 to expand along the first direction D1 when tension is applied to the first expandable dummy wire 31 in a direction that expands the first direction D1. Furthermore, when the tension is reduced, the shape-memory material may restore the shape of the first expandable dummy wire 31 to a shape that approaches the shape in a state in which the tension applied to the first expandable dummy wire 31 is zero.

[0041] Assume that the external force acting in the direction of extension along the first direction D1 between the two support bases 12 is further increased from the state shown in the plan view 502. In this case, as shown in the plan view 503, the first expandable dummy wiring 31 is deformed by extension to a state in which it has a substantially linear shape in plan view. Here, in this embodiment, the wiring length of the first expandable dummy wiring 31 is shorter than the wiring length of the first expandable wiring 21. Therefore, even when the first expandable dummy wiring 31 is extended to a substantially linear shape as shown in the plan view 503, the first expandable wiring 21 continues to maintain a meandering shape in plan view. In other words, even when the first expandable dummy wiring 31 is in a state in which it has been extended to the maximum along the first direction D1, the first expandable wiring 21 still has room to further extend along the first direction D1.

[0042] For example, suppose that the external force acting in the direction of extension along the first direction D1 between the two support bases 12 further increases from the state shown in the plan view 503. In this case, the first expandable dummy wiring 31 further expands due to deformation, such as a reduction in the thickness of the conductive portion 71 and the strain gauge 72 themselves. This deformation makes it difficult for the first expandable dummy wiring 31 to restore its original shape, even if the first expandable dummy wiring 31 contains a shape-memory material. If the external force further increases and the thickness of the first expandable dummy wiring 31 falls below a certain predetermined value, the first expandable dummy wiring 31 may break.

[0043] On the other hand, as described above, even in a state where the first expandable dummy wiring 31 is further expanded to the maximum extent along the first direction D1 from the state shown in the plan view 503, there is room for the first expandable wiring 21 to further expand along the first direction D1. For this reason, even in a state where the first expandable dummy wiring 31 is broken, it is possible to avoid the first expandable wiring 21 from immediately breaking.

[0044] <Relationship Between Strain and Stress> Even while the connected first expandable dummy wiring 31 is expanding or contracting, the current measuring unit 41 applies a current to the first expandable dummy wiring 31 and measures the electrical resistance or the value of the current flowing through the first expandable dummy wiring 31. As described above, the first expandable dummy wiring 31 is formed with a strain gauge 72. Therefore, by measuring the electrical resistance of the strain gauge 72 with the current measuring unit 41, at least one of the expansion / contraction measuring unit 43 and the expansion / contraction measuring unit of the IC 42 measures the expansion / contraction rate of the first expandable dummy wiring 31 in the first direction D1.

[0045] 6 is a graph showing the relationship between the strain S of the first expandable dummy wiring 31 measured by the strain gauge 72 and the measured value of the stress T applied to the first expandable dummy wiring 31. In the graph of FIG. 6, the horizontal axis represents the magnitude of the strain S of the first expandable dummy wiring 31, and the vertical axis represents the magnitude of the stress T applied to the first expandable dummy wiring 31.

[0046] When the first expandable dummy wiring 31 expands along the first direction D1, the strain S of the first expandable dummy wiring 31 measured by the strain gauge 72 increases. Therefore, the stress T associated with the first expandable dummy wiring 31, estimated from the measured value of the electrical resistance of the strain gauge 72 of the first expandable dummy wiring 31, increases in proportion to the strain S of the first expandable dummy wiring 31. Therefore, as shown in FIG. 6 , the strain S and the stress T are proportional to each other until a predetermined stress is generated in the first expandable dummy wiring 31.

[0047] When a stress equal to or greater than a predetermined value is generated in the first expandable dummy wiring 31, the strain S and stress T of the first expandable dummy wiring 31 no longer satisfy the proportional relationship. This is thought to be due to the fact that the external force applied to the first expandable dummy wiring 31 increases, causing the conductive portion 71 and the strain gauge 72 to further elongate due to deformation such as a reduction in the thickness of the conductor portion 71 and the strain gauge 72 themselves. For this reason, when a stress exceeding the yield point YP shown in FIG. 6 is generated in the first expandable dummy wiring 31, the strain S and stress T of the first expandable dummy wiring 31 no longer satisfy the proportional relationship.

[0048] Furthermore, when a stress equal to or greater than the breaking stress BT occurs in the first expandable dummy wiring 31, the first expandable dummy wiring 31 breaks. For this reason, the measured value of the stress T hardly changes above the breaking strain BS, which is the strain S at the time when the stress T associated with the first expandable dummy wiring 31 becomes the breaking stress BT.

[0049] As described above, by measuring the relationship between the strain S and the stress T of the first expandable dummy wiring 31, the expansion / contraction measuring unit and the expansion / contraction measuring unit 43 of the IC 42 can measure the expansion / contraction rate of the first expandable dummy wiring 31. In particular, by measuring that the strain S and the stress T are no longer proportional, the expansion / contraction measuring unit and the expansion / contraction measuring unit 43 of the IC 42 can measure that the stress T exceeding the yield point YP has been applied to the first expandable dummy wiring 31. Furthermore, in particular, by measuring that the measured value of the stress T does not change significantly regardless of the strain S, the expansion / contraction measuring unit and the expansion / contraction measuring unit 43 of the IC 42 can measure that the first expandable dummy wiring 31 has been broken.

[0050] <Estimation of Expansion / Contraction Ratio> The first expandable wiring 21 is formed between two pixels 2 formed on each of the two support bases 12 to which the first expandable dummy wiring 31 is connected. Furthermore, expansion and contraction of the first expandable dummy wiring 31 corresponds to expansion and contraction in the first direction D1 between the two support bases 12 to which the first expandable dummy wiring 31 is connected, and therefore corresponds to expansion and contraction in the first direction D1 between the two pixels 2 formed on each of the two support bases 12. Therefore, by measuring the expansion and contraction ratio of the first expandable dummy wiring 31, at least one of the expansion and contraction measuring unit and the expansion and contraction measuring unit 43 of the IC 42 can estimate the expansion and contraction ratio of the first expandable wiring 21 in the first direction.

[0051] In particular, both the first expandable wire 21 and the first expandable dummy wire 31 extend along the first direction D1. Alternatively, the display device 1 includes a plurality of first expandable dummy wires 31 for one first expandable wire 21. With the above configuration, the estimation accuracy of the expansion / contraction rate of the first expandable wire 21 in the first direction by the expansion / contraction measuring unit and the expansion / contraction measuring unit 43 of the IC 42 is improved.

[0052] For example, the expansion / contraction measuring unit and the expansion / contraction measuring unit 43 of the IC 42 may measure the tension applied to the first expandable dummy wiring 31 from the measured value of the stress T described above. In this case, the warning unit 44 may warn the user that the tension of the first expandable dummy wiring 31 measured by the expansion / contraction measuring unit and the expansion / contraction measuring unit 43 has reached a predetermined level or higher. For example, the warning unit 44 may be an extension warning unit that issues a warning to the user when the tension of the first expandable dummy wiring 31 is detected to be a predetermined tension that is lower than the tension at the yield point YP. In this way, the warning unit 44 can warn the user before a tension that will make the first expandable dummy wiring 31 unable to recover is applied to the first expandable dummy wiring 31.

[0053] The expansion / contraction measuring unit and the expansion / contraction measuring unit 43 of the IC 42 measure the tension applied to the first expandable dummy wiring 31, and thereby the expansion / contraction measuring unit and the expansion / contraction measuring unit 43 of the IC 42 can determine whether or not the tension is a tension that makes it impossible to restore the first expandable dummy wiring 31. In this way, by measuring the tension applied to the first expandable dummy wiring 31, the display device 1 can more precisely estimate the state of the first expandable dummy wiring 31.

[0054] Alternatively, the expansion / contraction measurement unit and the expansion / contraction measurement unit 43 of the IC 42 may determine whether the current value measured by the current measurement unit 41 has fallen below a predetermined value. The predetermined value may be the current value measured by the current measurement unit 41 when the first expandable dummy wiring 31 is broken. In this case, the expansion / contraction measurement unit and the expansion / contraction measurement unit 43 of the IC 42 can detect the break in the first expandable dummy wiring 31. The warning unit 44 may be a break warning unit that issues a warning to the user when the expansion / contraction measurement unit and the expansion / contraction measurement unit 43 of the IC 42 detects the break in the first expandable dummy wiring 31. In this way, the warning unit 44 can notify the user that the first expandable dummy wiring 31 has been broken.

[0055] At the time when the first expandable dummy wiring 31 breaks, the first expandable wiring 21 is not broken, but a tension close to the tension that may cause the first expandable wiring 21 to break is being applied to the first expandable wiring 21. For this reason, by knowing that the first expandable dummy wiring 31 has broken, the user can know that at that time the expandable base 11 has stretched to a level just before the first expandable wiring 21 breaks. In this way, the display device 1 allows the user to efficiently prevent the expandable base 11 from being stretched to a level that may cause the first expandable wiring 21 to break. When the wiring length of the first expandable dummy wiring 31 is shorter than the wiring length of the first expandable wiring 21, the display device 1 can notify the user that the expandable base 11 has stretched to a level just before the first expandable wiring 21 breaks, while reducing the possibility of the first expandable wiring 21 breaking.

[0056] Furthermore, since the first expandable dummy wiring 31 does not contribute to the light emission of the light-emitting element EL or the driving of the pixel circuit PC, the display device 1 may display on the display section DA as normal even if the first expandable dummy wiring 31 is broken, as long as the first expandable wiring 21 is not broken.

[0057] As described above, the display device 1 can estimate the expansion / contraction rate of the first expandable wiring 21 from the expansion / contraction rate of the first expandable dummy wiring 31 by the expansion / contraction measuring unit and the expansion / contraction measuring unit 43 of the IC 42. Therefore, the display device 1 does not require a design such as providing a strain gauge on the first expandable wiring 21 in order to directly measure the expansion / contraction rate of the first expandable wiring 21. Furthermore, the display device 1 makes it possible to estimate the expansion / contraction rate of the first expandable wiring 21 while eliminating the need for equipment or the like for measuring the expansion / contraction of the expandable base 11.

[0058] As described above, the first expandable wires 21 are wires related to driving the plurality of pixels 2. Therefore, the display device 1 can reduce deformation of the first expandable wires 21 connecting the pixels 2 by estimating whether or not the first expandable wires 21 have expanded by a predetermined amount or more, thereby reducing the impact on the display in the display unit DA. Furthermore, the display device 1 estimates the expansion / contraction rate of the first expandable wires 21 by measuring the expansion / contraction rate of the first expandable dummy wires 31. Therefore, the display device 1 can reduce the impact on light emission of the light-emitting elements EL of the pixels 2 that is caused by directly measuring the expansion / contraction rate of the first expandable wires 21, which are wires related to driving the plurality of pixels 2, thereby reducing the impact on the display in the display unit DA.

[0059] Therefore, the display device 1 that can estimate the expansion / contraction rate of the first expandable wires 21 while simplifying the first expandable wires 21 reduces the deformation of the wiring that connects the pixels 2 including the first expandable wires 21, while reducing the complexity or increase in cost. In particular, the display device 1 can estimate the expansion / contraction rate of the first expandable wires 21 by using the strain gauges 72 of the first expandable dummy wires 31. Therefore, the display device 1 does not require a device or the like that measures the length of the first expandable dummy wires 31 in the first direction D1, and enables the expansion / contraction rate of the first expandable wires to be estimated by a simpler configuration.

[0060] <Second elastic wire> Returning to reference to Fig. 1 , the display device 1 includes second elastic wires 22 that connect a set of pixels 2 different from the set of pixels 2 connected by the first elastic wires 21. The second elastic wires 22, for example, connect the pixels 2 of two support bases 12 that are arranged along the second direction D2 in a planar view. Furthermore, the second elastic wires 22 are formed to be able to expand and contract within a predetermined range along the second direction D2. For example, the second elastic wires 22 are wires that contribute to the emission of light from each pixel 2 including the two pixels 2 that are connected to them.

[0061] The display device 1 also includes second expandable dummy wires 32 that connect a set of support bases 12 different from the set of support bases 12 to which the first expandable dummy wires 31 are connected. In particular, the second expandable dummy wires 32 connect two support bases 12 on which two pixels 2 to which the second expandable wires 22 are connected are respectively formed, and extend along the second direction D2. The second expandable dummy wires 32 are formed to be expandable within a predetermined range along the second direction D2. The second expandable dummy wires 32 may be formed on both sides of the second expandable wires 22 in the first direction D1 in a plan view. For example, the second expandable dummy wires 32 are wires that do not contribute to light emission of each pixel 2.

[0062] The second expandable wires 22 and the second expandable dummy wires 32 may have the same shape and contain the same material as the first expandable wires 21 and the first expandable dummy wires 31. This allows the second expandable wires 22 and the second expandable dummy wires 32 to be formed in the same process as the first expandable wires 21 and the second expandable dummy wires 32. Therefore, the second expandable wires 22 and the second expandable dummy wires 32 reduce the manufacturing cost of the display device 1 or shorten the takt time for manufacturing the display device 1.

[0063] The current measuring units 41 may also be formed on both ends of the second expandable dummy wiring 32, and in this case, the current measuring units 41 may measure the value of a current flowing through the second expandable dummy wiring 32. The expansion / contraction measuring unit and the expansion / contraction measuring unit 43 of the IC 42 may be connected to the second expandable dummy wiring 32 via the leading wiring 5 and the current measuring unit 41. Therefore, the expansion / contraction measuring unit and the expansion / contraction measuring unit 43 of the IC 42 may measure the expansion / contraction rate of the second expandable dummy wiring 32 by the same method as the method for measuring the expansion / contraction rate of the first expandable dummy wiring 31. Therefore, the expansion / contraction measuring unit and the expansion / contraction measuring unit 43 of the IC 42 may estimate the expansion / contraction rate of the second expandable wiring 22 by the same method as the method for estimating the expansion / contraction rate of the first expandable wiring 21.

[0064] The display device 1 makes it possible to estimate the expansion / contraction rate of the second expandable wire 22 in the second direction D2 while simplifying the second expandable wire 22. Therefore, the display device 1 reduces deformation of the wiring that connects the pixels 2 including the second expandable wire 22 while reducing complexity or cost increases.

[0065] 1 among the in-plane directions of the stretchable base 11, in other words, in a third direction intersecting both the first direction D1 and the second direction D2. In this case, the display device 1 may estimate the expansion / contraction rate of the stretchable base 11 in the third direction by estimating both the expansion / contraction rate of the first stretchable wiring 21 and the expansion / contraction rate of the second stretchable wiring 22.

[0066] <Third elastic wire> The display device 1 further includes a third elastic wire 23 that connects a set of pixels 2 different from the set of pixels 2 connected by each of the first elastic wire 21 and the second elastic wire 22. The third elastic wire 23, for example, connects the pixels 2 of two support bases 12 that are arranged along the first direction D1 in plan view. Furthermore, the third elastic wire 23 is formed to be able to expand and contract within a predetermined range along the first direction D1. For example, the third elastic wire 23 is a wire that contributes to the emission of light from each pixel 2 including the two pixels 2 that it connects.

[0067] The display device 1 also includes third expandable dummy wires 33 that connect a set of support bases 12 different from the set of support bases 12 to which the first expandable dummy wires 31 and the second expandable dummy wires 32 are connected. In particular, the third expandable dummy wires 33 connect two support bases 12 on which two pixels 2 to which the third expandable wires 23 are connected are respectively formed, and extend along the first direction D1. The third expandable dummy wires 33 are formed to be expandable within a predetermined range along the first direction D1. The third expandable dummy wires 33 may be formed on both sides of the third expandable wires 23 in the second direction D2 in a plan view. For example, the third expandable dummy wires 33 are wires that do not contribute to light emission of each pixel 2.

[0068] The third expandable wires 23 and the third expandable dummy wires 33 may have the same shape and contain the same material as the first expandable wires 21 and the first expandable dummy wires 31. This allows the third expandable wires 23 and the third expandable dummy wires 33 to be formed in the same process as the first expandable wires 21 and the second expandable dummy wires 32. Therefore, the third expandable wires 23 and the third expandable dummy wires 33 reduce the manufacturing cost of the display device 1 or shorten the takt time for manufacturing the display device 1.

[0069] The current measuring unit 41 may also be formed on both ends of the third expandable dummy wiring 33, and in this case, the current measuring unit 41 may measure the value of a current flowing through the third expandable dummy wiring 33. The expansion / contraction measuring unit and the expansion / contraction measuring unit 43 of the IC 42 may be connected to the third expandable dummy wiring 33 via the leading wiring 5 and the current measuring unit 41. Therefore, the expansion / contraction measuring unit and the expansion / contraction measuring unit 43 of the IC 42 may measure the expansion / contraction rate of the third expandable dummy wiring 33 by the same method as the method for measuring the expansion / contraction rate of the first expandable dummy wiring 31. Therefore, the expansion / contraction measuring unit and the expansion / contraction measuring unit 43 of the IC 42 may estimate the expansion / contraction rate of the third expandable wiring 23 by the same method as the method for estimating the expansion / contraction rate of the first expandable wiring 21.

[0070] The display device 1 is capable of estimating the expansion / contraction rate of not only the first expandable wire 21 but also the third expandable wire 23. Therefore, the display device 1 reduces deformation of the wiring that connects the pixels 2 including the first expandable wire 21 and the third expandable wire 23 while reducing complexity or increase in cost.

[0071] A method for manufacturing the display device 1 according to this embodiment will be described with reference to Fig. 7. Fig. 7 is a flowchart showing a method for manufacturing the display device 1.

[0072] In the manufacturing method of the display device 1 according to this embodiment, first, an expandable base 11 is prepared (step S1). Preparation of the expandable base 11 may include deposition of a material, such as a resin, that is stretchable and elastic in the in-plane direction. The expandable base 11 may be deposited on a rigid substrate, such as a glass substrate.

[0073] Next, the support base 12 is formed on the stretchable base 11 (step S2). The support base 12 may be formed by forming a film on the stretchable base 11 by the same method as the stretchable base 11, and then patterning the film for each region where the pixels 2 are to be formed.

[0074] Next, the circuits and wiring of the display device 1 are formed (step S3). The circuits of the display device 1 may include, for example, the driver circuit DR, the pixel circuit PC, and the flexible printed circuit board FC. The wiring of the display device 1 may include the stretchable wiring, the stretchable dummy wiring, and the routing wiring 5. The specific method for forming the circuits and wiring of the display device 1 may be various methods, including conventionally known methods. In step S3, the current measurement unit 41, the IC 42, the stretch measurement unit 43, and the warning unit 44 may be formed.

[0075] Next, the light-emitting element EL is formed. The light-emitting element EL may be formed, for example, by sequentially depositing and patterning a conductive material used for the electrodes, a charge transport material used for the charge transport layer, and a light-emitting material in a suitable order.

[0076] Next, a sealing film 6 is formed (step S6). The sealing film 6 may be formed by depositing a sealing material containing at least one of an inorganic material and an organic material from above the expandable base 11 that overlaps at least the display unit DA in a plan view. In this manner, the display device 1 is manufactured. Note that if the expandable base 11 is formed on a rigid substrate in step S1, the expandable base 11 may be peeled off from the rigid substrate following step S6.

[0077] The display device 1 manufactured by the above-described method reduces the complexity or increase in cost while reducing deformation of the wiring connecting the pixels 2. Therefore, the above-described method for manufacturing the display device 1 enables the manufacture of a display device 1 that reduces deformation of the wiring connecting the pixels 2 while realizing simplification of each process, reduction in takt time, or reduction in manufacturing cost.

[0078] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining different technical means disclosed in the embodiments are also included in the technical scope of the present disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in the embodiments.

[0079] REFERENCE SIGNS LIST 1 Display device (stretchable display device) 2 Pixel 5 Leading wiring 11 Stretchable base 12 Support base 21 First stretchable wiring 22 Second stretchable wiring 23 Third stretchable wiring 31 First stretchable dummy wiring 32 Second stretchable dummy wiring 33 Third stretchable dummy wiring 41 Current measuring unit 42 IC (stretching measurement unit) 43 Stretching measurement unit 44 Warning unit (extension warning unit / disconnection warning unit) 72 Strain gauge D1 First direction D2 Second direction

Claims

1. A stretchable display device comprising: a stretchable base that is stretchable in a first direction among in-plane directions; a plurality of support bases that are formed on the stretchable base and each have pixels; first stretchable wiring that connects the pixels of at least two of the support bases and is stretchable in the first direction; first stretchable dummy wiring that connects the support bases on which the pixels to which the first stretchable wiring are connected are formed and is stretchable in the first direction; and an expansion / contraction measurement unit that measures the expansion rate of the first stretchable dummy wiring in the first direction and estimates the expansion rate of the first stretchable wiring in the first direction.

2. A stretchable display device as described in claim 1, wherein the first stretchable dummy wiring has a strain gauge that stretches in the first direction, and the stretch measurement unit measures the electrical resistance of the strain gauge to estimate the stretch rate of the first stretchable wiring in the first direction.

3. A stretchable display device according to claim 1 or 2, wherein the first stretchable wiring and the first stretchable dummy wiring both extend in the same direction as the first direction.

4. The stretchable display device according to any one of claims 1 to 3, wherein the stretchable base is also stretchable in a second direction perpendicular to the first direction among the in-plane directions, and is provided with second stretchable wirings that connect a set of pixels different from the set of pixels connected by the first stretchable wirings and are stretchable in the second direction, and second stretchable dummy wirings that connect the support bases on which the pixels connected by the second stretchable wirings are formed and are stretchable in the second direction.

5. A stretchable display device according to claim 4, wherein the second stretchable wiring has the same shape as the first stretchable wiring and contains the same material, and the second stretchable dummy wiring has the same shape as the first stretchable dummy wiring and contains the same material.

6. A stretchable display device according to any one of claims 1 to 5, comprising: a third stretchable wiring that connects a set of pixels different from the set of pixels connected by the first stretchable wiring and is stretchable in the first direction; and a third stretchable dummy wiring that connects the support bases on which the pixels connected by the third stretchable wiring are formed and is stretchable in the first direction.

7. A stretchable display device according to claim 6, wherein the third stretchable wiring has the same shape as the first stretchable wiring and contains the same material, and the third stretchable dummy wiring has the same shape as the first stretchable dummy wiring and contains the same material.

8. A stretchable display device according to any one of claims 1 to 7, wherein a plurality of first stretchable dummy wires are provided for one first stretchable wire.

9. The stretchable display device according to any one of claims 1 to 8, wherein the wiring length of the first stretchable dummy wiring is shorter than the wiring length of the first stretchable wiring.

10. A stretchable display device according to any one of claims 1 to 9, wherein the Young's modulus of the first stretchable dummy wiring is greater than the Young's modulus of the first stretchable wiring.

11. The stretchable display device according to any one of claims 1 to 10, wherein the stretch measuring unit measures the tension applied to the first stretchable dummy wiring.

12. A stretchable display device as described in any one of claims 1 to 11, further comprising an elongation warning unit that issues a warning to a user when the elongation rate of the first elongation dummy wiring measured by the elongation measurement unit becomes equal to or greater than a predetermined value.

13. A stretchable display device as described in any one of claims 1 to 12, wherein the first stretchable dummy wiring includes a shape memory material that, when tension is applied to the first stretchable dummy wiring in the direction in which the first stretchable dummy wiring extends and then the tension is reduced, restores the shape of the first stretchable dummy wiring to a shape that approaches the shape when the tension applied to the first stretchable dummy wiring is zero.

14. A stretchable display device as described in claim 13, wherein the stretch measurement unit detects that a predetermined tension lower than the tension at which the shape memory material is unable to restore the first stretchable dummy wiring is applied to the first stretchable dummy wiring.

15. A stretchable display device as described in any one of claims 1 to 14, further comprising a current measuring unit that applies a current to the first stretchable dummy wiring and measures the current flowing through the first stretchable dummy wiring, wherein the stretch measuring unit detects a break in the first stretchable dummy wiring when the current measured by the current measuring unit falls below a predetermined value.

16. The stretchable display device according to claim 15, further comprising a wire breakage warning unit that issues a warning to a user when the expansion / contraction measuring unit detects a wire breakage in the first expansion / contraction dummy wiring.

17. A stretchable display device as claimed in any one of claims 1 to 16, wherein the stretchable base includes, in a plan view, a display area in which the plurality of support bases, the first stretchable wirings, and the first stretchable dummy wirings are located, and a frame area located around the display area, and the stretchable display device is provided with routing wiring that is connected to the first stretchable dummy wirings and the stretch measurement unit and at least a portion of which is routed through the frame area.

18. The stretchable display device according to claim 17, further comprising a flexible printed circuit board including an IC connected to the routing wiring in the frame area, wherein at least a portion of the expansion / contraction measuring unit is located on the flexible printed circuit board.

19. The stretchable display device according to claim 17 or 18, wherein at least a portion of the expansion / contraction measuring section is located on the frame area.

20. A method for manufacturing a stretchable display device, comprising: preparing a stretchable base that is stretchable in a first direction among in-plane directions; forming a plurality of support bases, each having pixels, on the stretchable base; forming first stretchable wiring that connects the pixels of at least two of the support bases and is stretchable in the first direction; forming first stretchable dummy wiring that connects the support bases on which the pixels to which the first stretchable wiring are connected are formed and is stretchable in the first direction; and forming an expansion / contraction measuring unit that measures the expansion rate of the first stretchable dummy wiring in the first direction and estimates the expansion rate of the first stretchable wiring in the first direction.

Images