Display device

Abstract

A display device (1) is provided with: a display unit (2) having a light-emitting element; and a terminal unit (3) having wiring for supplying a display signal to the light-emitting element. The terminal unit (3) has a bent part (9) that protrudes outward by being bent so as to face the surface of the display unit (2) on the opposite side from a display surface (8). The direction in which the terminal unit (3) extends from the display unit (2) is defined as a first direction (13). The bent part (9) has a plurality of protrusions (10) that are positioned on the outer side of the bent part (9) and are arranged along a second direction (14) orthogonal to the first direction (13). The plurality of protrusions (10) contain a curable resin.

Description

Display device

[0001] The present disclosure relates to a display device including a display unit having a light-emitting element and a terminal unit having wiring for supplying a display signal to the light-emitting element.

[0002] A display device including a display unit having a light-emitting element and a terminal unit having wiring for supplying a display signal to the light-emitting element is known (Patent Document 1).

[0003] In this display device, resin is applied over the entire area of the bent portion of the terminal unit so that the resin thickness is uniform.

[0004] Japanese Patent Application Laid-Open No. 2018-194632

[0005] However, since the outermost surface of the resin applied to the bent portion of the terminal unit is flat, when the back surface of the cover glass contacts the resin of the bent portion, they contact each other in a surface-to-surface manner, so there is a problem that the cover glass and the bent portion are likely to stick together.

[0006] The display device of the present disclosure includes a display unit having a light-emitting element and a terminal unit having wiring for supplying a display signal to the light-emitting element, and the terminal unit has a bent portion that is bent so as to face the surface opposite to the display surface of the display unit and protrudes outward. The direction in which the terminal unit extends from the display unit is defined as the first direction, and the bent portion has a plurality of convex portions arranged along a second direction that is located outside the bent portion and orthogonal to the first direction, or has a concavo-convex portion having a plurality of concavo-convexities along the second direction on the outside of the bent portion. The plurality of convex portions and the concavo-convex portion contain a curable resin.

[0007] One aspect of the present disclosure can provide a display device capable of suppressing adhesion between the bent portion of the terminal unit and the cover glass.

[0008] This is a cross-sectional view of the display device according to Embodiment 1. This is a view of the display unit and terminal unit provided on the above-mentioned display device, seen from the direction along arrow A shown in Figure 1. This is a cross-sectional view along plane XX' shown in Figure 2. This is a perspective view showing the bent portion provided on the terminal unit. This is a perspective view showing the bent portion of the display device according to the comparative example. This is a view of the display unit and terminal unit provided on the display device according to the comparative example, seen along arrow A shown in Figure 1. This is a cross-sectional view along plane XX' shown in Figure 6. This is a cross-sectional view showing the manufacturing method of the display device according to the comparative example. This is a cross-sectional view showing the manufacturing method of the display device according to the comparative example. This is a cross-sectional view showing the manufacturing method of the display device according to the comparative example. This is an image showing the sticking phenomenon caused by the manufacturing method of the display device according to the comparative example. This is a perspective view showing the bent portion provided on the terminal unit of the display device according to Embodiment 2.

[0009] (Embodiment 1) Figure 1 is a cross-sectional view of the display device 1 according to Embodiment 1. Figure 2 is a view of the display unit 2 and terminal unit 3 provided on the display device 1, taken from the direction along arrow A shown in Figure 1. Note that Figure 2 shows the state in which the cover glass 4 has been removed to make the protrusion 10 easier to see, and the state before the terminal unit 3 is bent. Figure 3 is a cross-sectional view taken along the plane XX' shown in Figure 2. Figure 4 is a perspective view showing the bent portion 9 provided on the terminal unit 3. Note that Figure 4 shows the state in which the cover glass 4 has been removed to make the bent portion 9 easier to see.

[0010] The display device 1 comprises a display unit 2 having light-emitting elements and a terminal unit 3 having wiring 12 for supplying display signals to the light-emitting elements. The terminal unit 3 has a bent portion 9 that protrudes outward when bent so as to face the side of the display unit 2 opposite to the display surface 8. If the direction in which the terminal unit 3 extends from the display unit 2 is defined as the first direction 13, the bent portion 9 has a plurality of protrusions 10 that are located outside the bent portion 9 and are arranged along a second direction 14 perpendicular to the first direction 13. The plurality of protrusions 10 contain a curable resin. This curable resin includes a photocurable resin or a thermosetting resin. Preferably, this curable resin contains an ultraviolet curable resin. The wiring 12 extends along the first direction 13. At least a portion of the plurality of protrusions 10 extends along the first direction 13. The display device 1 further comprises a cover glass 4 disposed on the display surface 8 side of the display unit 2. When the display surface 8 is viewed from above, the bent portion 9 and the cover glass 4 overlap. The display device 1 further comprises a first reinforcing plate 5 provided relative to the display unit 2, and a second reinforcing plate 6 located on the opposite side of the first reinforcing plate 5 from the side where the display unit 2 is located. The bent portion 9 is curved to connect the first reinforcing plate 5 and the second reinforcing plate 6. The display device 1 further comprises a frame portion 7 arranged around the display unit 2. The terminal portion 3 extends from the display unit 2 through the frame portion 7. The display unit 2, the frame portion 7, and the terminal portion 3 constitute a single display panel. In the display device 1 configured in this way, the bent portion 9 of the terminal portion 3, which has wiring 12 for supplying display signals to the light-emitting element, is provided with a plurality of protrusions 10 located on the outside of the bent portion 9 and arranged along the second direction 14. This reduces the area in contact with the cover glass 4. Therefore, adhesion between the bent portion 9 of the terminal portion 3 and the cover glass 4 can be suppressed.

[0011] Figure 5 is a perspective view showing the bent portion 9 of the comparative example display device, with the cover glass 4 removed to make the bent portion 9 easier to see. Figure 6 is a view of the display unit 2 and terminal unit 3 provided in the comparative example display device, along the arrow A shown in Figure 1, with the cover glass 4 removed to make the protrusion 90 easier to see, and showing the terminal unit 3 before it is bent. Figure 7 is a cross-sectional view along the surface XX' shown in Figure 6. Figures 8 to 10 are cross-sectional views showing the manufacturing method of the comparative example display device. Figure 11 is an image showing the sticking phenomenon that occurred as a result of the manufacturing method of the comparative example display device. Components similar to those described above are given the same reference numerals, and their detailed descriptions are not repeated.

[0012] In flexible displays, a narrow bezel is achieved by crimping and mounting a terminal section 3 (Flexible Printed Circuits) onto an FPC (Flexible Printed Circuits) and then folding it to the back of the display surface 8 (display area) of the display section 2. After attaching a cover glass (CG) 4 to the display panel via a polarizing plate 15 and an optical clear adhesive (OCA), the terminal section 3 is folded with the display surface 8 (terminal surface) of the panel facing downwards.

[0013] When the terminal portion 3 is bent, the wiring 12 at the bent portion 9 may break. To suppress this breakage, as shown in Figure 6, a UV (ultraviolet) curing resin 90 is applied to the bent portion 9.

[0014] In other words, in order to prevent the wiring 12 of the bent portion 9 from breaking when the terminal portion 3 is bent, UV-curing resin 90 is applied to the bent portion 9 and the wiring layer is positioned in the neutral plane. In the neutral plane, neither tensile stress acting on the outside of the bent portion 9 nor compressive stress acting on the inside occurs.

[0015] However, as shown in Figure 9, if the terminal portion 3 hangs down and the UV-curing resin 90 comes into contact with the back surface of the cover glass 4, it may stick to the cover glass 4. If the terminal portion 3 is bent in this state, as shown in Figures 10 and 11, the UV-curing resin 90 will peel off from the terminal portion 3 of the display panel and remain on the back surface of the cover glass 4, which is a problem.

[0016] The cause of this is thought to be as follows: When UV-curing resin 90 is exposed to air, oxygen inhibition occurs, making it prone to poor curing of the surface of the UV-curing resin 90. As a result, even if UV irradiation is continued, the UV curing of the surface of the UV-curing resin 90 does not progress, leaving a tacky (sticky) feeling on the resin surface, which is thought to be the cause of the back surface of the cover glass 4 sticking to the UV-curing resin 90.

[0017] Before bending the terminal portion 3, as shown in Figure 9, the surface of the UV-curing resin 90 applied to the bent portion 9 of the terminal portion 3 and the back surface (printed surface) of the cover glass 4 are left in contact for a certain period of time, causing them to stick together. When the terminal portion 3 is bent, as shown in Figure 10, the UV-curing resin 90 peels off from the terminal portion 3 of the display panel and sticks to the back surface of the cover glass 4.

[0018] Therefore, in this embodiment, the following improvements were made. Specifically, in order to prevent the oxygen inhibition phenomenon of the UV-curable resin 90, it is necessary to perform UV curing of the UV-curable resin 90 in an environment where oxygen and the UV-curable resin 90 do not easily come into contact, for example, in a closed space filled with nitrogen. However, this would increase the size of the process equipment, making it difficult to realize.

[0019] This UV-curing resin 90 is dispensed from a nozzle using an inkjet method for drawing and application. The resin is applied in the same direction as the wiring 12 of the terminal section 3 of the display panel, and the drawing conditions are set so that the resin peaks of adjacent drawing lines do not come into contact with each other. This intentionally creates areas where resin is applied and areas where it is not, so that the resin-coated areas have an uneven shape with multiple protrusions 10 arranged in a row. This reduces the area in contact with the back surface of the cover glass 4 by the bent portion 9. In other words, contact with the cover glass 4 is made only at the protrusions 10.

[0020] Conventionally, as shown in Figure 6, the UV-curing resin 90 is applied with a uniform thickness along the second direction 14, and the outermost surface of the UV-curing resin 90 is finished to be flat. As a result, the contact area between the bent portion 9 and the cover glass 4 is large.

[0021] On the other hand, in this embodiment, resin is applied by drawing with a nozzle along a direction parallel to the wiring 12 of the terminal section 3 of the display panel. Furthermore, by setting the drawing conditions so that the resin peaks of adjacent drawing lines do not come into contact with each other, areas where resin is applied and areas where it is not applied are intentionally created, so that the resin-coated area has an uneven shape including multiple protrusions 10. This reduces the area that comes into contact with the back surface of the cover glass 4.

[0022] In other words, in this embodiment, as shown in Figures 2 and 3, UV-curable resin is formed for multiple protrusions 10 that constitute the uneven shape. As a result, the area in contact between the bent portion 9 and the cover glass 4 is reduced.

[0023] The UV-curing resin 90 applied to the bent portion 9 is cured by UV light, but due to oxygen inhibition, the outermost surface of the resin remains sticky. The cover glass 4 is directly above the UV-curing resin 90, and in mobile devices such as smartphones where thinness is a strong requirement, the clearance between the UV-curing resin 90 and the back surface of the cover glass 4 is often less than 0.1 mm. If weight is applied from above for a certain period of time for some reason before bending, the UV-curing resin 90 and the back surface of the cover glass 4 will be in contact, and the stickiness of the surface of the UV-curing resin 90 will cause it to stick to the back surface of the cover glass 4. If the terminal portion 3 is bent without noticing that it has stuck, the UV-curing resin 90 may peel off from the terminal portion 3.

[0024] As in this embodiment, by providing areas where UV-curing resin is applied and areas where it is not applied, and by providing irregularities in the shape of the resin-coated areas, the contact area between the UV-curing resin and the back surface of the cover glass 4 is reduced, thereby suppressing the UV-curing resin from adhering to the back surface of the cover glass 4.

[0025] Furthermore, if the uneven shape is formed perpendicular to the wiring 12 of the terminal section 3, that is, if the resin is applied while drawing with the nozzle perpendicular to the wiring 12 of the terminal section 3 of the display panel, and if the resin peaks of adjacent drawing lines are set so as not to come into contact with each other, then it is possible to create an uneven shape in the resin application area. However, since the recessed area is located perpendicular to the bending direction (first direction 13), it becomes a bending point, and the bent part cannot be bent into a nice R shape, resulting in cracks in the wiring layer of the wiring 12 and rendering the effect ineffective.

[0026] (Embodiment 2) Figure 12 is a perspective view showing the bent portion 9 provided on the terminal portion 3 of the display device 1A according to Embodiment 2. Figure 12 shows the state with the cover glass 4 removed to make the bent portion 9 easier to see. Components similar to those described above are denoted by the same reference numerals, and their detailed descriptions will not be repeated.

[0027] In Embodiment 1, areas where resin is applied and areas where it is not applied are provided, but it is also possible to create irregularities by varying the thickness of the resin.

[0028] First, similar to Embodiment 1, the resin is applied by drawing a nozzle in a direction parallel to the wiring 12 of the terminal section 3 of the display panel, intentionally creating areas where the resin is applied and areas where it is not, and then cured with UV light.

[0029] Next, resin is applied to the previously uncoated area so that the resin thickness is thinner than when it was applied earlier, and then cured with UV light. This makes it possible to create an uneven surface on the resin surface of the bent portion 9 due to the difference in resin thickness.

[0030] After applying a resin of a uniform thickness to the entire resin coating area and curing it, an uneven surface may be created by applying and curing another layer of resin in a direction parallel to the wiring 12 of the terminal section 3, while ensuring that the resin of adjacent drawing lines does not come into contact with each other.

[0031] In Embodiment 1, an area where resin is not applied is provided in the bent portion 9. However, in that area, the wiring 12 of the wiring layer cannot be positioned in the neutral plane, and tensile and compressive stresses are applied when bending. In Embodiment 2, since no area where resin is not applied is created in the bent portion 9, the stress on the wiring layer when bending is reduced compared to Embodiment 1, and the occurrence of cracks in the wiring 12 can be suppressed.

[0032] Thus, the bent portion 9 of the display device 1A has a plurality of uneven portions 11 located on the outside of the bent portion 9 and forming a plurality of protrusions and recesses along the second direction 14. These uneven portions 11 consist of thicker protrusions 11a and thinner recesses 11b arranged alternately along the second direction 14. For example, the thickness of the protrusions 11a can be 60 μm and the thickness of the recesses 11b can be 30 μm.

[0033] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

[0034] 1 Display device 2 Display unit 3 Terminal unit 4 Cover glass 5 First reinforcing plate 6 Second reinforcing plate 7 Frame unit 8 Display surface 9 Bent unit 10 Convex unit 11 Concave / concave unit

Claims

1. A display device comprising: a display unit having a light-emitting element; and a terminal unit having wiring for supplying a display signal to the light-emitting element, wherein the terminal unit has a bent portion that protrudes outward when bent so as to face the surface opposite to the display surface of the display unit, the direction in which the terminal unit extends from the display unit is defined as a first direction, and the bent portion has a plurality of protrusions located on the outside of the bent portion and arranged along a second direction perpendicular to the first direction, or a plurality of uneven portions located on the outside of the bent portion and forming an uneven surface along the second direction, and the plurality of protrusions and the uneven portions are made of a curable resin.

2. The display device according to claim 1, wherein the wiring extends along the first direction, and at least a portion of the plurality of protrusions or at least a portion of the plurality of protrusions included in the uneven portion extends along the first direction.

3. The display device according to claim 1 or 2, further comprising a cover glass disposed on the display surface side of the display unit, wherein the bent portion and the cover glass overlap when the display surface is viewed from above.

4. The display device according to any one of claims 1 to 3, wherein the curable resin includes a photocurable resin or a thermosetting resin.

5. The display device according to claim 4, wherein the curable resin includes an ultraviolet curing resin.

6. The display device according to any one of claims 1 to 5, further comprising a first reinforcing plate provided with respect to the display portion, and a second reinforcing plate located on the opposite side of the first reinforcing plate from the side on which the display portion is located, wherein the bent portion is curved to connect the first reinforcing plate and the second reinforcing plate.

7. The display device according to any one of claims 1 to 6, further comprising a frame portion arranged around the display portion, the terminal portion extending from the display portion through the frame portion, and the display portion, the frame portion, and the terminal portion constituting a single display panel.

Images