WO2025163817A1 - Stretchable display device and method of manufacturing stretchable display device - Google Patents

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

This disclosure relates to a stretchable display device that can stretch in an in-plane direction, and a method for manufacturing such a stretchable display device.

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 multiple substrates, each of which includes subpixels.

US Patent Application Publication No. 2021/0027671

In the stretchable display device described in Patent Document 1, if an external force greater than a predetermined value is applied in the direction of extension of the substrate, the connection wiring may break or the shape of the connection wiring may not be restored. In the stretchable display device described in Patent Document 1, providing a separate device to measure the external force applied to the substrate would increase the complexity and cost of the stretchable display device.

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 pixels; first stretchable wires that connect the pixels of at least two of the support bases and are stretchable in the first direction; first stretchable dummy wires that connect the support bases on which the pixels connected to the first stretchable wires are formed and are stretchable in the first direction; and an expansion/contraction measurement 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.

A method for manufacturing 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.

This reduces deformation of the connecting wiring while minimizing the complexity or cost increase of the stretchable display device.

FIG. 2 is an enlarged plan view of a part of the display device according to the embodiment. 1 is a schematic diagram of a display device according to an embodiment. 1 is a schematic side cross-sectional view of a display device according to an embodiment. 3A and 3B are schematic diagrams illustrating examples of side cross sections of first expandable wires and first expandable dummy wires according to the embodiment. FIG. 10 is an enlarged plan view of a part of the display device according to the embodiment, showing deformation of the stretchable wiring and the stretchable dummy wiring accompanying expansion of the stretchable base of the display device. 10 is a graph showing the relationship between the strain of the first expandable dummy wire measured by a strain gauge according to the embodiment and the measured value of the stress applied to the first expandable dummy wire. 1 is a flowchart illustrating a method for manufacturing a display device according to an embodiment.

[Embodiment 1]
<Display Device Overview>
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 section DA including a plurality of pixels 2, and a frame region NA that is positioned around the display section 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 section DA by controlling light emission from each of the plurality of light-emitting elements EL formed in the display section DA via the driver circuit DR and the pixel circuit PC.

The light-emitting element EL is, for example, a field injection type light-emitting element, and includes, for example, an organic light-emitting material, an organic phosphorescent material, or a quantum dot material as a light-emitting material. The pixel circuit PC includes, for example, a transistor such as a TFT, and drives each light-emitting element EL individually based on a signal from the driver circuit DR.

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 Figure 1. Figure 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 a portion of the multiple pixels 2 of the display device 1 and a portion of the frame area NA.

<Stretchable substrate and supporting substrate>
As shown in FIG. 1 , the display device 1 includes a stretchable substrate 11 at a position overlapping at least the display unit in a planar view. One of the in-plane directions of the stretchable substrate 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 substrate 11 according to this embodiment is stretchable within a predetermined range in at least the first direction D1. In particular, the stretchable substrate 11 is stretchable within a predetermined range in each of the first direction D1 and the second direction D2. The stretchable substrate 11 may include a material, such as a resin, that is elastic and capable of restoring its shape. The stretchable substrate 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 substrate 11 is applied to the stretchable substrate 11 in either the first direction D1 or the second direction D2.

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 area DA in a plan view. For example, the display device 1 includes a plurality of support bases 12, which are arranged along each of the first direction D1 and the second direction D2. Each support base 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 a material that is more rigid than the stretchable base 11, for example.

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

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

As shown in FIG. 3, a pixel 2 including a light-emitting element EL and a pixel circuit PC is formed on each of the multiple 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 pixel 2 may be sealed on the stretchable substrate 11 by being covered with the light-transmitting sealing film 6. The sealing film 6 may be formed commonly on the stretchable substrate 11 in a planar view. The sealing film 6 may also stretch in accordance with the extension of the stretchable substrate 11 in the in-plane direction.

<Stretchable wiring>
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 plan view, for example. The first elastic wires 21 are formed to be expandable and contractible within a predetermined range along the first direction D1 by a structure described later.

For this reason, even if the distance between the two support bases 12 increases as a result of the stretching of the stretchable base 11 in the first direction D1, the first stretchable wiring 21 stretches, and the first stretchable wiring 21 maintains the connection between the two pixels 2. Note that if the stretchable base 11 stretches and the first stretchable wiring 21 then contracts, the first stretchable wiring 21 may contract so as to restore its original shape.

The first expandable wiring 21 may connect two pixels 2 together and transmit signals between the two pixels 2. For example, the first expandable wiring 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 that pixel 2 to emit light. The first expandable wiring 21 may also supply a signal to the pixel circuit PC of at least one of the two connected pixels 2 to drive that pixel circuit PC. Furthermore, the first expandable wiring 21 may relay the transmission of a signal supplied to a pixel 2 other than the two connected pixels 2.

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

For this reason, even if 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 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 emission of the light-emitting element EL and the driving of the pixel circuit PC.

<Examples of stretchable wiring>
An example of a specific configuration of the first expandable wire 21 and the first expandable 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 expandable wire 21 and the first expandable 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 expandable wire 21 and two first expandable dummy wires 31 that are parallel to the second direction D2 and are formed on both sides of the first expandable wire 21 in the second direction D2, of the display device 1.

As shown in the schematic diagram 401 of FIG. 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. In this case, the conductive portion 71 is expandable in the first direction D1 together with the first expandable wire 21.

Furthermore, the first expandable dummy wiring 31 may have a strain gauge 72 that covers 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 it 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 wiring 31 using the 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 wiring 31 can be formed more simply.

Note that 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 approximately 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 has a conductive portion 71 and a strain gauge 72, but this is not limited to this. For example, the first expandable dummy wire 31 may have a low conductivity or insulating member and a 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.

Furthermore, as shown in schematic diagram 403, the first expandable wire 21 may have a flat plate shape, in which 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 first expandable dummy wire 31 shown in schematic diagram 403 can be formed even more simply by depositing and patterning a conductive material.

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

<Expansion measurement section and warning section>
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.

The display device 1 may include an IC 42 and an expansion/contraction measuring unit 43 in the frame area NA. For example, the display device 1 may include a flexible printed circuit board FC in the frame area 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 area NA, particularly on the expansion/contraction base 11 in the frame area 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.

The IC 42 and the expansion/contraction measurement unit 43 each measure the expansion/contraction rate of the first expandable dummy wiring 31 in the first direction D1 using a method described below, and estimate the expansion/contraction rate of the first expandable wiring 21 in the first direction D1. In other words, the IC 42 may be formed with at least a portion of the expansion/contraction measurement unit that measures the expansion/contraction rate of the first expandable dummy wiring 31 in the first direction D1.

In addition, the "expansion/contraction ratio of the wiring" in this disclosure may refer to the ratio of extension of the wiring based on the wiring length when no external force is applied to the wiring in the extension direction of the wiring. Alternatively, the "expansion/contraction ratio of the wiring" in this disclosure may refer to the ratio of the length of the wiring in a specified in-plane direction of the expandable base 11 to the wiring length of the wiring.

By including at least a part of the expansion/contraction measurement unit in the IC 42, it is possible to consolidate the functions of the expansion/contraction measurement unit into the IC 42, further simplifying the configuration of the expansion/contraction measurement unit. On the other hand, by providing the display device 1 with the expansion/contraction measurement unit 43 in the frame region NA, it is possible to form the expansion/contraction measurement unit 43 in a position close to the first expansion/contraction dummy wiring 31. As a result, the expansion/contraction measurement unit 43 further shortens or simplifies the routing wiring 5, simplifying the configuration of the display device 1.

The IC 42 and the expansion/contraction measuring unit 43 may each be connected to the current measuring unit 41 via the routing wiring 5 shown in FIG. 1. As a result, the IC 42 and the expansion/contraction measuring unit 43 may each 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 routing wiring 5 connects each first expansion/contraction dummy wiring 31 to the IC 42 and the expansion/contraction measuring unit 43 via each current measuring unit 41, and may also be routed to the frame area NA.

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

Furthermore, the display device 1 may be provided with a warning unit 44, for example, in the frame area NA. The warning unit 44 issues a warning to the user when the extension rate of the first expandable dummy wiring 31 measured by the method described below reaches a predetermined level or greater. The warning unit 44 may be provided with, for example, a lamp such as an LED that issues the warning by lighting up, or a speaker that issues the warning by sound, etc.

<Stretching and contracting of wiring>
The expansion and contraction of the first expandable wires 21 and the first expandable dummy wires 31 in the first direction D1 will be described with reference to Fig. 5. Fig. 5 is an enlarged plan view of a portion 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 wires 21 and first expandable dummy wires 31 formed between the support bases 12.

For example, as shown in the plan view 501 of FIG. 5, the first expandable wiring 21 and the first expandable dummy wiring 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 that causes them to extend along the first direction D1 between two support bases 12, the first expandable wiring 21 and the first expandable dummy wiring 31 meander in the second direction D2.

In the above state, suppose an external force is applied between the two support bases 12 in a direction that causes them to stretch along the first direction D1. In this case, as shown in plan view 502, each of the first expandable wiring 21 and the first expandable dummy wiring 31 stretches along the first direction D1 by deforming so that the width of the meandering decreases. As a result, the first expandable wiring 21 and the first expandable dummy wiring 31 stretch along the first direction D1 while preventing changes that affect conductivity, such as breakage or a reduction in thickness.

The first expandable wire 21 and the first expandable dummy wire 31 have a predetermined elasticity and shape memory property. Therefore, as the external force decreases, the first expandable wire 21 and the first expandable dummy wire 31 shorten along the first direction D1. When the external force is removed, the first expandable wire 21 and the first expandable dummy wire 31 may shorten along the first direction D1 to the shape shown in the plan view 501, for example.

In other words, at least the first expandable dummy wire may contain 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 causes it to expand along 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 when the tension applied to the first expandable dummy wire 31 is zero.

Suppose that the external force acting in the direction of stretching along the first direction D1 between the two support bases 12 increases further from the state shown in plan view 502. In this case, as shown in plan view 503, the first expandable dummy wiring 31 is deformed by stretching until it becomes approximately linear in plan view. 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. For this reason, even when the first expandable dummy wiring 31 is stretched until it becomes approximately linear as shown in plan view 503, the first expandable wiring 21 continues to maintain a serpentine shape in plan view. In other words, even when the first expandable dummy wiring 31 is stretched to the maximum extent along the first direction D1, the first expandable wiring 21 still has room to stretch further along the first direction D1.

For example, suppose that the external force acting in the direction of extension along the first direction D1 between the two support bases 12 from the state shown in plan view 503 further increases. In this case, the first expandable dummy wiring 31 will further expand due to deformation, such as reducing 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 return to its original shape, even if the first expandable dummy wiring 31 contains a shape-memory material. If the external force increases further and the thickness of the first expandable dummy wiring 31 falls below a certain predetermined value, the first expandable dummy wiring 31 may break.

On the other hand, as described above, even when the first expandable dummy wiring 31 is further expanded along the first direction D1 to the maximum extent from the state shown in the plan view 503, the first expandable wiring 21 still has room to expand further along the first direction D1. Therefore, even when the first expandable dummy wiring 31 is broken, the first expandable wiring 21 can be prevented from immediately breaking.

<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.

FIG. 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.

When the first expandable dummy wiring 31 stretches 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 Figure 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.

When stress 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 further elongation due to deformation such as reducing the thickness of the conductive portion 71 and strain gauge 72 themselves. For this reason, when stress exceeding the yield point YP shown in Figure 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.

Furthermore, if stress equal to or greater than the breaking stress BT occurs in the first expandable dummy wiring 31, the first expandable dummy wiring 31 will break. Therefore, above the breaking strain BS, which is the strain S at the point when the stress T associated with the first expandable dummy wiring 31 becomes the breaking stress BT, the measured value of stress T will hardly change.

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

<Estimation of expansion rate>
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 rate 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 rate of the first expandable wiring 21 in the first direction.

In particular, both the first expandable wiring 21 and the first expandable dummy wiring 31 extend along the first direction D1. Alternatively, the display device 1 includes multiple first expandable dummy wirings 31 for one first expandable wiring 21. This configuration improves the accuracy with which the expansion/contraction measurement unit and expansion/contraction measurement unit 43 of the IC 42 estimate the expansion/contraction rate of the first expandable wiring 21 in the first direction.

For example, the expansion/contraction measurement unit and expansion/contraction measurement 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 measurement unit and expansion/contraction measurement unit 43 of the IC 42 has reached a predetermined level or higher. For example, the warning unit 44 may be an expansion 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 level lower than the tension at the yield point YP. This allows the warning unit 44 to warn the user before a tension is applied to the first expandable dummy wiring 31 that will make it impossible for the first expandable dummy wiring 31 to restore its original shape.

By measuring the tension applied to the first expandable dummy wiring 31 with the expansion/contraction measuring unit and expansion/contraction measuring unit 43 of the IC 42, the expansion/contraction measuring unit and expansion/contraction measuring unit 43 can determine whether or not the tension in question is a tension that makes it impossible for the first expandable dummy wiring 31 to restore its original shape. In this way, by measuring the tension applied to the first expandable dummy wiring 31, the display device 1 can more accurately estimate the state of the first expandable dummy wiring 31.

Alternatively, the expansion/contraction measurement unit and 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 expansion/contraction measurement unit 43 of the IC 42 can detect a 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 expansion/contraction measurement unit 43 of the IC 42 detects a 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.

At the time the first expandable dummy wiring 31 breaks, the first expandable wiring 21 is not broken, but a tension close to the tension that could 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 stretching to a level that could 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.

Incidentally, 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 unit DA as normal even if the first expandable dummy wiring 31 is broken, as long as the first expandable wiring 21 is not broken.

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 using the expansion/contraction measurement unit 43 of the IC 42. As a result, the display device 1 does not require a design such as providing a strain gauge on the first expandable wiring 21 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, etc., to measure the expansion/contraction of the expandable base 11.

As described above, the first expandable wiring 21 is wiring related to the driving of multiple pixels 2. Therefore, by estimating whether the first expandable wiring 21 has expanded by a predetermined amount or more, the display device 1 can reduce deformation of the first expandable wiring 21 connecting each pixel 2 and reduce the impact on the display in the display unit DA. Furthermore, the display device 1 estimates the expansion rate of the first expandable wiring 21 by measuring the expansion rate of the first expandable dummy wiring 31. Therefore, the display device 1 can reduce the impact on the light emission of the light-emitting element EL of each pixel 2 that comes with directly measuring the expansion rate of the first expandable wiring 21, which is wiring related to the driving of multiple pixels 2, and reduce the impact on the display in the display unit DA.

Therefore, the display device 1, which can estimate the expansion/contraction rate of the first expandable wiring 21 while simplifying the first expandable wiring 21, reduces deformation of the wiring connecting the pixels 2 including the first expandable wiring 21, while reducing complexity or cost increases. In particular, the display device 1 can estimate the expansion/contraction rate of the first expandable wiring 21 using the strain gauges 72 of the first expandable dummy wiring 31. As a result, the display device 1 does not require equipment or the like for measuring the length of the first expandable dummy wiring 31 in the first direction D1, and enables estimation of the expansion/contraction rate of the first expandable wiring with a simpler configuration.

<Second telescopic wiring>
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. The second elastic wires 22 are formed to be expandable and contractible 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.

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 the two support bases 12 on which the 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 the emission of light from each pixel 2.

The second expandable wires 22 and the second expandable dummy wires 32 may have the same shape as the first expandable wires 21 and the first expandable dummy wires 31 and may contain the same material. 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.

The current measuring unit 41 may also be formed on both ends of the second expandable dummy wiring 32, in which case the current measuring unit 41 may measure the value of the current flowing through the second expandable dummy wiring 32. The expansion measuring unit and expansion measuring unit 43 of the IC 42 may be connected to the second expandable dummy wiring 32 via the routing wiring 5 and the current measuring unit 41. Therefore, the expansion measuring unit and expansion measuring unit 43 of the IC 42 may measure the expansion rate of the second expandable dummy wiring 32 using the same method as the method for measuring the expansion rate of the first expandable dummy wiring 31. Therefore, the expansion measuring unit and expansion measuring unit 43 of the IC 42 may estimate the expansion rate of the second expandable wiring 22 using the same method as the method for estimating the expansion rate of the first expandable wiring 21.

The display device 1 simplifies the second expandable wiring 22 while making it possible to estimate the expansion/contraction rate of the second expandable wiring 22 in the second direction D2. Therefore, the display device 1 reduces deformation of the wiring connecting pixels 2 including the second expandable wiring 22 while reducing complexity or cost increases.

For example, the stretchable base 11 may be stretchable in a diagonal direction toward the plane of the paper in FIG. 1 among the in-plane directions of the stretchable base 11, in other words, in a third direction that intersects with both the first direction D1 and the second direction D2. In this case, the display device 1 may estimate the stretch rate of the stretchable base 11 in the third direction by estimating both the stretch rate of the first stretchable wiring 21 and the stretch rate of the second stretchable wiring 22.

<Third telescopic wiring>
Furthermore, the display device 1 includes third elastic wires 23 that connect a set of pixels 2 different from the sets of pixels 2 connected by each of the first elastic wires 21 and the second elastic wires 22. The third elastic wires 23, for example, connect the pixels 2 of two support bases 12 that are arranged along the first direction D1 in a planar view. Furthermore, the third elastic wires 23 are formed to be able to expand and contract within a predetermined range along the first direction D1. For example, the third elastic wires 23 are wires that contribute to the emission of light from each pixel 2 including the two pixels 2 that are connected to them.

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

The third expandable wires 23 and the third expandable dummy wires 33 may have the same shape as the first expandable wires 21 and the first expandable dummy wires 31 and may contain the same material. 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.

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

The display device 1 is capable of estimating the expansion rate of not only the first expandable wiring 21 but also the third expandable wiring 23. Therefore, the display device 1 reduces deformation of the wiring connecting the pixels 2, including the first expandable wiring 21 and the third expandable wiring 23, while reducing complexity or cost increases.

The manufacturing method of the display device 1 according to this embodiment will be described with reference to Figure 7. Figure 7 is a flowchart showing the manufacturing method of the display device 1.

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

Next, a 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 using the same method as for the stretchable base 11, and then patterning it for each region where the pixels 2 are to be formed.

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, pixel circuit PC, and 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. Various methods, including conventionally known methods, may be used to form the circuits and wiring of the display device 1. In step S3, the current measurement unit 41, IC 42, stretch measurement unit 43, and warning unit 44 may also be formed.

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 in the electrodes, a charge transport material used in the charge transport layer, and a light-emitting material in an appropriate order.

Next, the 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 stretchable base 11 that overlaps at least the display unit DA in a planar view. In this manner, the display device 1 is manufactured. Note that if the stretchable base 11 is formed on a rigid substrate in step S1, the stretchable base 11 may be peeled off from the rigid substrate following step S6.

The display device 1 manufactured by the above-described method reduces deformation of the wiring connecting the pixels 2 while reducing complexity or cost increases. 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 simplifying each process, reducing takt time, and reducing manufacturing costs.

This 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 each embodiment are also included in the technical scope of this disclosure. Furthermore, new technical features can be created by combining the technical means disclosed in each embodiment.

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 (stretchability measuring unit)
43 Expansion/contraction measurement unit 44 Warning unit (extension warning unit/disconnection warning unit)
72 Strain gauge D1 First direction D2 Second direction

Claims (20)

an elastic substrate that is stretchable in a first direction among in-plane directions;
a plurality of supporting substrates formed on the stretchable substrate, each having a pixel;
a first expandable wiring that connects the pixels of at least two of the supporting bases and is expandable in the first direction;
a first expandable dummy wiring that connects the support bases on which the pixels to be connected by the first expandable wiring are formed and is expandable in the first direction;
A stretchable display device comprising: an expansion/contraction measuring unit that measures an expansion/contraction rate of the first expandable dummy wiring in the first direction and estimates an expansion/contraction rate of the first expandable wiring in the first direction. the first expandable dummy wiring has a strain gauge that expands and contracts in the first direction,
The stretchable display device according to claim 1 , wherein the expansion/contraction measuring unit measures the electrical resistance of the strain gauge to estimate the expansion/contraction rate of the first expandable wiring in the first direction. 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. The stretchable substrate is also stretchable in a second direction perpendicular to the first direction among the in-plane directions,
A second elastic wiring that connects a set of pixels different from the set of pixels connected to the first elastic wiring and is stretchable in the second direction;
4. The stretchable display device according to claim 1, further comprising: a second elastic dummy wiring that connects the support bases on which the pixels to which the second elastic wiring are connected are formed and is stretchable in the second direction. the second elastic wire has the same shape as the first elastic wire and contains the same material as the first elastic wire,
The stretchable display device according to claim 4 , wherein the second stretchable dummy wiring has the same shape and is made of the same material as the first stretchable dummy wiring. A third elastic wiring that connects a set of pixels different from the set of pixels connected to the first elastic wiring and is stretchable in the first direction;
The stretchable display device according to any one of claims 1 to 5, further comprising: a third elastic dummy wiring that connects the support bases on which the pixels to which the third elastic wiring are connected are formed and is stretchable in the first direction. the third elastic wire has the same shape as the first elastic wire and contains the same material as the first elastic wire,
The stretchable display device according to claim 6 , wherein the third stretchable dummy wiring has the same shape and is made of the same material as the first stretchable dummy wiring. A stretchable display device according to any one of claims 1 to 7, wherein one first stretchable wiring is provided with a plurality of first stretchable dummy wirings. A 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. 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. A stretchable display device according to any one of claims 1 to 10, wherein the stretch measurement unit measures the tension applied to the first stretch dummy wiring. The stretchable display device of any one of claims 1 to 11, further comprising an expansion warning unit that issues a warning to the user when the expansion rate of the first expandable dummy wiring measured by the expansion measurement unit exceeds a predetermined value. The stretchable display device 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 state in which the tension applied to the first stretchable dummy wiring is zero. The stretchable display device described in claim 13, wherein the stretch measurement unit detects when 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. a current measuring unit that applies a current to the first expandable dummy wiring and measures the current flowing through the first expandable dummy wiring;
15. The stretchable display device according to claim 1, wherein the expansion/contraction measuring unit detects a break in the first expansion/contraction dummy wiring when the current measured by the current measuring unit becomes equal to or less than a predetermined value. The stretchable display device of claim 15, further comprising a break warning unit that issues a warning to the user when the expansion/contraction measurement unit detects a break in the first expansion/contraction dummy wiring. 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,
A stretchable display device as described in any one of claims 1 to 16, comprising a wiring that is connected to the first stretchable dummy wiring and the stretch measurement unit, and at least a portion of which is routed to the frame region. a flexible printed circuit board including an IC connected to the lead wiring in the frame area;
The stretchable display device according to claim 17, wherein at least a portion of the expansion/contraction measuring unit is located on the flexible printed circuit board. A stretchable display device as described in claim 17 or 18, wherein at least a portion of the expansion/contraction measuring section is located on the frame area. Preparing a stretchable substrate that is stretchable in a first direction among in-plane directions;
forming a plurality of supporting substrates, each having pixels, on the stretchable substrate;
Forming first expandable wirings that connect the pixels of at least two of the supporting bases and are expandable in the first direction;
forming a first expandable dummy wiring that connects the support bases on which the pixels to be connected by the first expandable wiring are formed and is expandable in the first direction;
and forming an expansion/contraction measuring unit that measures the expansion/contraction rate of the first expandable dummy wiring in the first direction and estimates the expansion/contraction rate of the first expandable wiring in the first direction.