CN108665804A - Foldable electronic paper display device and manufacturing method thereof - Google Patents

Abstract

The invention discloses a foldable electronic paper display device and a manufacturing method thereof. The electronic paper display panel is provided with a bending area and two plane areas respectively adjacent to two edges of the bending area. When the electronic paper display panel is folded, the two planar areas are approximately parallel. The rear protection sheet is positioned on the back surface of the electronic paper display panel and is positioned in the plane area and the bending area. The rear protective sheet is provided with at least one groove, the groove is at least partially positioned in the bending area, and the width of the groove is smaller than that of the bending area. Because the rear protection sheet is provided with the groove positioned in the bending area, the internal stress between layers can be reduced in the bending area with larger strain difference, and the rear protection sheet is prevented from being separated from the back surface of the electronic paper display panel.

Description

Foldable electronic paper display device and manufacturing method thereof

technical field

The invention relates to a foldable electronic paper display device and a manufacturing method of the foldable electronic paper display device.

Background technique

Due to the advent of flexible panels (such as electronic paper display panels), foldable display devices have appeared in the current electronic product market. Generally speaking, in order to protect the front and back of the flexible panel, two protective sheets are used to cover the front and back of the flexible panel respectively.

However, when the flexible panel is bent along the center line, the two protective sheets are located on opposite sides of the flexible panel, so there will be a maximum amount of deformation to generate interlayer internal stress. As a result, in regions with large strain differences, delamination may occur between layers of the display device, for example, the protective sheet is detached from the surface of the flexible panel. In addition, if the flexible panel is an electronic paper panel, in the dynamic fatigue test, there will be a phenomenon of stress concentration at the periphery of the bending area, which will cause the display medium layer with the microcapsules to break.

Contents of the invention

An object of the present invention is to provide a foldable electronic paper display device that can reduce the interlayer internal stress in the bending area with large strain difference and prevent the rear protection sheet from detaching from the back of the electronic paper display panel.

According to an embodiment of the present invention, a foldable electronic paper display device includes an electronic paper display panel and a rear protection sheet. The electronic paper display panel has a bending area and two planar areas respectively adjacent to two edges of the bending area. When the electronic paper display panel is folded, the two planar areas are roughly parallel. The rear protection sheet is located on the back of the electronic paper display panel, and is located in the plane area and the bending area. The rear protection sheet has at least one groove, and the groove is at least partially located in the bending area, and the width of the groove is smaller than the width of the bending area.

In one embodiment of the present invention, the width of the groove is W, the radius of curvature of the bending area is R cm (mm), and 1 cm<W<πR cm (π: pi).

In one embodiment of the present invention, the groove is located in the center of the bending area.

In an embodiment of the present invention, a part of the trench is located in the planar region, and a junction between one of the planar regions and the bending region is exposed by the trench.

In one embodiment of the present invention, the above-mentioned rear protection sheet has two grooves, a part of each groove is located in the planar region, and the junctions between the planar region and the bending region are respectively exposed by the grooves.

In an embodiment of the present invention, the above-mentioned rear protection sheet has two grooves, a first section, a second section and a third section. The first section and the second section are respectively located in the plane area. The third section is located in the bending zone. The grooves are respectively located between the first section and the third section and between the second section and the third section.

In an embodiment of the present invention, the third section of the rear protection sheet further has a plurality of grooves.

In one embodiment of the present invention, the above-mentioned back protection sheet has a first part, a second part and a third part. The first part and the second part are respectively located in the plane area. The third part is located in the bending area and extends into the plane area. The third part has a different material than the first part, and the first part has the same material as the second part.

In one embodiment of the present invention, the above groove is located in the third part of the rear protection sheet.

In an embodiment of the present invention, the hardness of the first portion and the second portion is greater than that of the third portion.

In an embodiment of the present invention, the ductility of the third part is greater than the ductility of the first part and the second part.

In an embodiment of the present invention, the material of the third part is silica gel, and the materials of the first part and the second part are polyethylene terephthalate.

In one embodiment of the present invention, the top view shape of the groove is straight line, sinusoidal, square or triangular.

In an embodiment of the present invention, the above-mentioned foldable electronic paper display device further includes a front protection sheet. The front protection sheet is located on the back-to-back front of the e-paper display panel.

Another object of the present invention is to provide a method for manufacturing a foldable electronic paper display device.

According to an embodiment of the present invention, a method for manufacturing a foldable electronic paper display device includes: attaching a rear protection sheet to the back of the electronic paper display panel, wherein the electronic paper display panel has a bending area and adjacent bending areas respectively Two flat areas on both edges. The back protection sheet is cut to form at least one groove, wherein the groove is at least partially located in the bending area.

In the above-mentioned embodiments of the present invention, although the electronic paper display panel will produce two planar regions and a bending region when it is folded, since the rear protection sheet has grooves at least partially located in the bending region, it can be used in areas with large strain differences. The bending area can reduce the interlayer internal stress and prevent the back protection sheet from detaching from the back of the electronic paper display panel. In addition, the stress concentration phenomenon at the edge of the bending area can be improved to avoid damage to the electronic paper display panel and prolong the service life.

Description of drawings

FIG. 1 is a cross-sectional view of a foldable electronic paper display device in an unfolded state according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the foldable electronic paper display device in FIG. 1 in a folded state.

3A-3D illustrate top views of trenches according to various embodiments of the present invention.

FIG. 4 is a cross-sectional view of a foldable electronic paper display device in an unfolded state according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view of a foldable electronic paper display device in an unfolded state according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view of the foldable electronic paper display device in FIG. 5 in a folded state.

FIG. 7 is a cross-sectional view of a foldable electronic paper display device in an unfolded state according to an embodiment of the present invention.

FIG. 8 is a cross-sectional view of the foldable electronic paper display device in FIG. 7 in a folded state.

FIG. 9 is a cross-sectional view of a foldable electronic paper display device in an unfolded state according to an embodiment of the present invention.

FIG. 10 is a cross-sectional view of the foldable electronic paper display device in FIG. 9 in a folded state.

FIG. 11 is a cross-sectional view of a foldable electronic paper display device in an unfolded state according to an embodiment of the present invention.

FIG. 12 is a cross-sectional view of the foldable electronic paper display device in FIG. 11 in a folded state.

Detailed ways

Several embodiments of the present invention are described below with reference to the accompanying drawings. In order to simplify the accompanying drawings, some well-known and commonly used structures and components will be shown in a simple and schematic manner.

FIG. 1 shows a cross-sectional view of a foldable electronic paper display device 100 in an unfolded state according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the foldable electronic paper display device 100 of FIG. 1 in a folded state. Referring to FIG. 1 and FIG. 2 at the same time, the foldable electronic paper display device 100 includes an electronic paper display panel 110 and a rear protection sheet 120 . The electronic paper display panel 110 has a bending area A1 and two planar areas A2 and A3 adjacent to two edges of the bending area A1 respectively. When the electronic paper display panel 110 is folded, the bending area A1 is approximately U-shaped, and the two planar areas A2 and A3 are approximately parallel. The electronic paper display panel 110 has a back side 112 and a front side 114 opposite to each other, wherein the front side 114 is a display surface. The rear protection sheet 120 is located on the back surface 112 of the electronic paper display panel 110 , and the rear protection sheet 120 is located in the bending area A1 and the plane areas A2 , A3 . In addition, the rear protection sheet 120 has at least one groove 122 , and the groove 122 is at least partially located in the bending area A1 , and the width W1 of the groove 122 is smaller than the width of the bending area A1 . In this embodiment, the groove 122 of the rear protection sheet 120 is hollowed out, that is, the depth of the groove 122 is approximately equal to the thickness of the rear protection sheet 120 , but this is not intended to limit the present invention.

In addition, the foldable electronic paper display device 100 may further include a front protection sheet 130 . The front protection sheet 130 is located on the front surface 114 of the electronic paper display panel 110 and can be used to protect the electronic paper display panel 110 .

In this embodiment, when the electronic paper display panel 110 is folded, the curvature radius of the bending area A1 is R centimeters (mm), and the width W1 of the groove 122 of the rear protection sheet 120 is less than πR centimeters, and the width W1 is greater than 1 centimeter (mm), that is, 1 cm<W1<πR cm. The entire groove 122 may be located in the bending area A1 , for example, in the center of the bending area A1 , so that part of the back surface 112 of the electronic paper display panel 110 in the bending area A1 may be exposed by the groove 122 of the rear protection sheet 120 .

When the foldable electronic paper display device 100 is bent, although the electronic paper display panel 110 will be folded to produce planar areas A2, A3 and bending area A1, since the rear protective sheet 120 is at least partially located in the bending area A1 Therefore, the internal stress between layers can be reduced and redistributed in the bending area A1 where the strain difference is large, so as to prevent the back protection sheet 120 from detaching from the back surface 112 of the electronic paper display panel 110 . In addition, since the groove 122 of the rear protection sheet 120 can improve the stress concentration phenomenon at the edge of the bending area A1, when unfolding and folding the foldable electronic paper display device 100, the damage of the electronic paper display panel 110 can be avoided and the service life can be extended. For example, the breakage of the microcapsules of the display medium layer at the junction of the bending area A1 and the planar areas A2 and A3 can be avoided.

In addition, when the electronic paper display panel 110 is unfolded and used, since the width W1 of the groove 122 is smaller than the width of the bending area A1, the rear protection sheet 120 can maintain sufficient supporting force in the bending area A1 to avoid bending. The fold area A1 is recessed. When the electronic paper display panel 110 has a touch function, it is helpful for the user to press the bending area A1, and the sensitivity and uniformity of the touch can be improved, so that the user will not be in contact with the bending area A1 when pressing. The hand feeling when pressing the flat areas A2 and A3 is different. Furthermore, when the user watches from above the front surface 114 of the electronic paper display panel 110, because the width W1 of the groove 122 is small, it is possible to avoid color blocks, color differences or boundaries in the display screen between the bending area A1 and the plane areas A2, A3, Improve visual experience.

In addition, when manufacturing the foldable electronic paper display device 100, the rear protective sheet 120 can be attached to the back surface 112 of the electronic paper display panel 110, and then the rear protective sheet 120 is cut to form the groove 122, so that the groove 122 is at least partially Located in the bending area A1. For example, the rear protection sheet 120 can be cut with a knife or a laser to form the groove 122 , which is not intended to limit the invention. The manufacturing method of the foldable electronic paper display device 100 can save the time for attaching multiple protective sheets 120 to a single electronic paper display panel 110 , and can save assembly time and manpower.

3A-3D illustrate top views of trenches according to various embodiments of the present invention. The rear protection sheet 120 may have different forms of grooves. For example, the top view of the groove 122 of the rear protection sheet 120 in FIG. 1 is linear, as shown in FIG. 3A . However, the shape of the groove of the rear protection sheet 120 is not limited to a straight line. In FIG. 3B , the top view shape of the groove 122 a of the rear protection sheet 120 is a sinusoidal waveform. In FIG. 3C , the top view shape of the groove 122 b of the rear protection sheet 120 is a square wave. In FIG. 3D , the top view shape of the groove 122 c of the rear protection sheet 120 is a triangular waveform.

It should be understood that the connection relationship and functions of the components that have been described will not be repeated, and will be described first. In the following description, other forms of rear protection sheets of the foldable electronic paper display device will be described.

FIG. 4 is a cross-sectional view of a foldable electronic paper display device 100a in an unfolded state according to an embodiment of the present invention. As shown in the figure, the foldable electronic paper display device 100a includes an electronic paper display panel 110 and a rear protection sheet 120a. The difference from the embodiment in FIG. 1 is that the width W2 of the groove 122d of the rear protection sheet 120a is greater than the width of the bending area A1 of the electronic paper display panel 110, so that the entire bending area A1, part of the planar area A2 and part of the planar area A3 is exposed by trench 122d. When the electronic paper display panel 110 is folded, the radius of curvature of the bending area A1 is R, and the width W2 of the groove 122d of the rear protection sheet 120a is smaller than the sum of the widths of the bending area A1, the flat area A2, and the flat area A3 (the following inequality is expressed as A1+A2+A3 is shown), and the width W2 is greater than πR, that is, πR<W2<A1+A2+A3.

FIG. 5 shows a cross-sectional view of a foldable electronic paper display device 100b in an unfolded state according to an embodiment of the present invention. FIG. 6 is a cross-sectional view of the foldable electronic paper display device 100b of FIG. 5 in a folded state. Referring to FIG. 5 and FIG. 6 at the same time, the foldable electronic paper display device 100b includes an electronic paper display panel 110 and a rear protection sheet 120b. The difference from the embodiment shown in Fig. 1 and Fig. 2 is that: the rear protection sheet 120b has two grooves 122e, 122f. In addition, a part of the trench 122e is located in the plane area A2, and a part is located in the bending area A1. A part of the trench 122f is located in the plane area A3, and a part is located in the bending area A1. Therefore, the junction of the planar region A2 and the bending region A1 is exposed by the trench 122e, and the junction of the planar region A3 and the bending region A1 is exposed by the trench 122f.

In other words, the rear protection sheet 120 b has a first section 124 , a second section 126 and a third section 128 . The first section 124 and the second section 126 are located in the planar areas A2 and A3 respectively. The third section 128 is located in the bending area A1. The trench 122e is located between the first section 124 and the third section 128 , and the trench 122f is located between the second section 126 and the third section 128 .

In other embodiments, the rear protection sheet 120b may have one of the grooves 122e, 122f, which is not intended to limit the present invention.

FIG. 7 shows a cross-sectional view of a foldable electronic paper display device 100c in an unfolded state according to an embodiment of the present invention. FIG. 8 is a cross-sectional view of the foldable electronic paper display device 100c of FIG. 7 in a folded state. Referring to FIG. 7 and FIG. 8 at the same time, the foldable electronic paper display device 100c includes an electronic paper display panel 110 and a rear protection sheet 120c. The difference from the embodiment shown in FIG. 5 and FIG. 6 is that the third section 128a of the rear protection sheet 120c also has a plurality of grooves 122g. The grooves 122g of these third sections 128a help the bending of the rear protection sheet 120c and the electronic paper display panel 110, so that the electronic paper display panel 110 is not easily damaged due to stress concentration, and the third section of the rear protection sheet 120c 128a can also maintain sufficient support for the bending area A1.

FIG. 9 shows a cross-sectional view of a foldable electronic paper display device 100d in an unfolded state according to an embodiment of the present invention. FIG. 10 is a cross-sectional view of the foldable electronic paper display device 100d of FIG. 9 in a folded state. Referring to FIG. 9 and FIG. 10 at the same time, the foldable electronic paper display device 100d includes an electronic paper display panel 110 and a rear protection sheet 120d. The difference from the embodiment shown in FIG. 1 and FIG. 2 lies in that the rear protection sheet 120d has a first part 125 , a second part 127 and a third part 129 with different materials. The first portion 125 and the second portion 127 are located in the planar regions A2 and A3 respectively. The third portion 129 is located in the bending area A1 and extends into the planar areas A2 and A3. The grooves 122h, 122i of the rear protection sheet 120d are located in the third portion 129 of the rear protection sheet 120d.

In this embodiment, the material of the third part 129 of the rear protection sheet 120d is different from that of the first part 125, the material of the third part 129 is also different from that of the second part 127, and the material of the first part 125 is different from that of the second part 125. The material of part 127 is the same. For example, the hardness of the first part 125 and the second part 127 of the rear protection sheet 120d is greater than the hardness of the third part 129, and the extensibility of the third part 129 is greater than the extensibility of the first part 125 and the second part 127, so that the electronic paper The planar areas A2 and A3 of the display panel 110 can be respectively supported by the harder first part 125 and the second part 127 , and the bending area A1 can be supported by the softer third part 129 .

In this way, the material of the third part 129 of the protective sheet 120d and the grooves 122h and 122i in it all contribute to the bending of the rear protective sheet 120d and the electronic paper display panel 110, so that the electronic paper display panel 110 is not easy to collapse due to stress concentration. damage, and the third portion 129 of the rear protection sheet 120d can still maintain sufficient support for the bending area A1.

In this embodiment, the material of the third part 129 of the rear protection sheet 120d can be silica gel, and the material of the first part 125 and the second part 127 can be polyethylene terephthalate (PET). It is not intended to limit the invention.

It should be understood that the grooves in each embodiment of the present invention can be in the form of the grooves shown in FIG. 3A to FIG. 3D , depending on the needs of the designer.

FIG. 11 shows a cross-sectional view of a foldable electronic paper display device 100e in an unfolded state according to an embodiment of the present invention. FIG. 12 is a cross-sectional view of the foldable electronic paper display device 100e of FIG. 11 in a folded state. The difference from the embodiment shown in FIG. 1 and FIG. 2 is that the groove 122j of the rear protection sheet 120e is not hollowed out, that is, the depth of the groove 122j is smaller than the thickness of the rear protection sheet 120e. With such a design, in the bending area A1 , the position corresponding to the groove 122j on the back surface 112 of the electronic paper display panel 110 will be covered by the thinner part of the rear protection sheet 120 without being exposed from the groove 122j. The grooves in each embodiment of the present invention can be in the form of the groove 122j shown in FIG. 11 and FIG. 12 , depending on the needs of the designer.

Although the present invention has been disclosed above in terms of implementation, it is not intended to limit the present invention. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, this The scope of protection of the invention should be defined by the claims.

Claims (15)

1. A foldable electronic paper display device, characterized in that it comprises: The electronic paper display panel has a bending area and two planar areas respectively adjacent to two edges of the bending area, and when the electronic paper display panel is folded, the two planar areas are approximately parallel; and The rear protection sheet is located on the back of the electronic paper display panel, and is located in the two plane areas and the bending area, the rear protection sheet has at least one groove, and the groove is at least partially located on the In the bending area, the width of the groove is smaller than the width of the bending area. 2. The foldable electronic paper display device according to claim 1, wherein the width of the groove is W, the radius of curvature of the bending area is R, and 1 cm<W<πR cm. 3. The foldable electronic paper display device according to claim 1, wherein the groove is located at the center of the bending area. 4. The foldable electronic paper display device according to claim 1, wherein a part of the groove is located in the planar region, and one of the two planar regions is in contact with the bent The junctions of the regions are exposed by the trenches. 5. The foldable electronic paper display device according to claim 1, wherein the rear protection sheet has two grooves, a part of each of the grooves is located in the planar area, and the The junctions between the two planar regions and the bending region are respectively exposed by the two grooves. 6. The foldable electronic paper display device according to claim 1, wherein the rear protection sheet has two grooves, a first section, a second section and a third section, and the first section A section and the second section are respectively located in the two plane areas, the third section is located in the bending area, and the two grooves are respectively located in the first section and the between the third sections and between the second section and the third section. 7. The foldable electronic paper display device according to claim 6, wherein the third section of the rear protective sheet further has a plurality of grooves. 8. The foldable electronic paper display device according to claim 1, wherein the rear protection sheet has a first part, a second part and a third part, and the first part and the second part are located at Among the two planar regions, the third part is located in the bending region and extends into the two planar regions, and the material of the third part is different from that of the first part, and the first part The material of one part is the same as that of the second part. 9. The foldable electronic paper display device according to claim 8, wherein the groove is located in the third portion of the rear protection sheet. 10. The foldable electronic paper display device according to claim 8, wherein the hardness of the first part and the second part is greater than that of the third part. 11. The foldable electronic paper display device according to claim 8, wherein the extensibility of the third part is greater than the extensibility of the first part and the second part. 12. The foldable electronic paper display device according to claim 8, wherein the material of the third part is silica gel, and the material of the first part and the second part is polyethylene terephthalate diester. 13. The foldable electronic paper display device according to claim 1, wherein the top view shape of the groove is a straight line, a sinusoidal waveform, a square waveform or a triangular waveform. 14. The foldable electronic paper display device according to claim 1, further comprising: The front protection sheet is located on the front side of the electronic paper display panel facing away from the back side. 15. A method for manufacturing a foldable electronic paper display device, comprising: attaching the rear protective sheet to the back of the electronic paper display panel, wherein the electronic paper display panel has a bending area and two planar areas respectively adjacent to two edges of the bending area; and Cutting the back protection sheet to form at least one groove, wherein the groove is at least partially located in the bending region.