TW201837578A - Foldable electronic paper display device and manufacturing method thereof - Google Patents

Abstract

A foldable electronic paper display (EPD) device includes an electronic paper display panel and a back protection sheet. The EPD panel has a flexible area and two plane areas that are respectively adjacent to two edges of the flexible area. When the EPD panel is folded, the two plane areas are substantially parallel. The back protection sheet is located on a back surface of the EPD panel and in the plane areas and the flexible area. The back protection sheet has at least one trench, and at least a portion of the trench is in the flexible area.

Description

 Foldable electronic paper display device and method of manufacturing same  

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

Due to the advent of flexible panels, such as electronic paper display panels, foldable display devices have emerged in the current electronics market. In general, 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 that there is a maximum deformation amount to generate inter-layer internal stress. As a result, in a region where the strain difference is large, the display device may delaminate between the layers, for example, the protective sheet is detached from the surface of the flexible panel. Further, when the flexible panel is an electronic paper panel, in the dynamic fatigue test, stress concentration is concentrated on the periphery of the curved region, and the display medium layer having the microcapsules is broken.

One aspect of the present invention is a foldable electronic paper display device.

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

In an embodiment of the invention, the groove has a width W, and the radius of curvature of the bending zone is R mm (mm), and 1 mm < W < π R mm (π: pi).

In an embodiment of the invention, the groove is located at a center of the bending zone.

In an embodiment of the invention, a portion of the trench is located in the planar region, and a boundary between one of the planar regions and the bent region is exposed by the trench.

In an embodiment of the invention, the back protection sheet has two grooves, a part of each groove is located in the plane area, and a boundary between the plane area and the bending area is exposed by the groove.

In an embodiment of the invention, the 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 zone. The third section is located in the bend zone. The trenches 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 invention, the third section of the rear protective sheet further has a plurality of grooves.

In an embodiment of the invention, the rear protective sheet has a first portion, a second portion, and a third portion. The first part and the second part are respectively located in the plane area. The third portion is located in the bend zone and extends into the planar zone. The material of the third part is different from the material of the first part. The material of the first part is the same as the material of the second part.

In an embodiment of the invention, the groove is located in the third portion of the rear protective sheet.

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

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

In an embodiment of the invention, the material of the third portion is silicone, and the material of the first portion and the second portion is polyethylene terephthalate.

In one embodiment of the present invention, the shape of the trench in a plan view is a linear shape, a chord waveform, a square waveform, or a triangular waveform.

In an embodiment of the invention, the foldable electronic paper display device further includes a front protective sheet. The front protective sheet is located on the front side of the electronic paper display panel facing away from the back.

One aspect of the present invention is a method of 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 protective sheet to a back surface of an electronic paper display panel, wherein the electronic paper display panel has a bending region and a plurality of adjacent bending regions respectively Two flat areas of the edge. The protective sheet is cut to form at least one groove, wherein the groove is at least partially located in the bending zone.

In the above embodiment of the present invention, although the two-plane area and the bending area are generated when the electronic paper display panel is folded, since the rear protection sheet has a groove at least partially located in the bending area, the bending difference is large. The folded area can reduce the internal stress of the interlayer to prevent the rear protective sheet from being detached from the back surface of the electronic paper display panel. In addition, the stress concentration at the edge of the bending zone can be improved, and the electronic paper display panel can be prevented from being damaged and the service life can be prolonged.

100, 100a~100e‧‧‧Foldable electronic paper display device

110‧‧‧electronic paper display panel

112‧‧‧Back

114‧‧‧ positive

120, 120a~120e‧‧‧protection film

122, 122a~122j‧‧‧ trench

124‧‧‧First section

125‧‧‧Part 1

126‧‧‧second section

127‧‧‧Part II

128, 128a‧‧‧ third section

129‧‧‧Part III

130‧‧‧Pre-protective film

A1‧‧‧Bending area

A2, A3‧‧‧ flat area

W1, W2‧‧‧ width

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

3A through 3D are top views of trenches in accordance with various embodiments of the present invention.

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

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

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

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

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

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

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

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

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

The embodiments of the present invention are illustrated in the following drawings, and in the drawings, FIG.

1 is a cross-sectional view showing 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 showing the foldable electronic paper display device 100 of Fig. 1 in a folded state. Referring also to FIGS. 1 and 2, the foldable electronic paper display device 100 includes an electronic paper display panel 110 and a rear protective sheet 120. The electronic paper display panel 110 has a bending area A1 and two flat areas A2 and A3 adjacent to both edges of the bending area A1. When the electronic paper display panel 110 is folded, the bending area A1 is substantially U-shaped, and the two flat areas A2 and A3 are substantially parallel. The electronic paper display panel 110 has opposing back faces 112 and front faces 114, with the front side 114 being the display face. The rear protective sheet 120 is located on the back surface 112 of the electronic paper display panel 110, and the rear protective sheet 120 is located in the bending area A1 and the flat areas A2, A3. In addition, the rear protective 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 the present embodiment, the groove 122 of the rear protective sheet 120 is hollow, that is, the depth of the groove 122 is substantially equal to the thickness of the rear protective sheet 120, but is not intended to limit the present invention.

Further, the foldable electronic paper display device 100 may further include a front protective sheet 130. The front protective 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 the present embodiment, when the electronic paper display panel 110 is folded, the radius of curvature of the bending region A1 is R mm (mm), and the width W1 of the groove 122 of the rear protective sheet 120 is less than π R mm, and the width W1 More than 1 mm (mm), which is 1 mm <W1 < π R mm. The entire groove 122 may be located in the bending area A1, for example, in the center of the bending area A1, so that the partial back surface 112 of the electronic paper display panel 110 at the bending area A1 may be exposed by the groove 122 of the rear protective sheet 120.

After the foldable electronic paper display device 100 is bent, although the electronic paper display panel 110 is folded to produce the flat areas A2, A3 and the bending area A1, since the rear protective sheet 120 has at least partially located in the bending area A1 The groove 122, therefore, the bending area A1 having a large difference in strain can reduce the inter-layer internal stress, redistributing the inter-layer internal stress, and preventing the rear protective sheet 120 from being detached from the back surface 112 of the electronic paper display panel 110. In addition, since the groove 122 of the rear protective sheet 120 can improve the stress concentration phenomenon at the edge of the bending portion A1, when the foldable electronic paper display device 100 is unfolded and folded, the electronic paper display panel 110 can be prevented from being damaged and the service life can be prolonged. For example, it is avoided that the microcapsules of the display medium layer are broken at the boundary of the bending zone A1 and the planar zones A2, A3.

In addition, when the electronic paper display panel 110 is used in an unfolded state, since the width W1 of the groove 122 is smaller than the width of the bending area A1, the rear protective sheet 120 can maintain sufficient supporting force in the bending area A1 to avoid bending. The fold area A1 creates a depression. When the electronic paper display panel 110 has a touch function, it is helpful for the user to press the hand in the bending area A1, and the sensitivity and uniformity of the touch can be improved, so that the user does not press the bending area A1. There is a difference in the feel when pressing the flat areas A2 and A3. Moreover, when the user views from above the front surface 114 of the electronic paper display panel 110, since the width W1 of the groove 122 is small, color patches, chromatic aberrations or boundaries can be avoided in the bending area A1 and the flat areas A2 and A3. To enhance the visual experience.

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

3A through 3D are top views of trenches in accordance with various embodiments of the present invention. The back protective sheet 120 can have different forms of grooves. For example, the groove 122 of the protective sheet 120 of FIG. 1 has a linear shape in plan view, as shown in FIG. 3A. However, the shape of the groove of the rear protective sheet 120 is not limited to a straight shape. In Fig. 3B, the shape of the groove 122a of the rear protective sheet 120 is a chord waveform. In the 3Cth diagram, the shape of the groove 122b of the rear protective sheet 120 is a square waveform. In the 3D drawing, the shape of the groove 122c of the rear protective sheet 120 is a triangular waveform.

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

Fig. 4 is a cross-sectional view showing the foldable electronic paper display device 100a in an unfolded state according to an embodiment of the present invention. As shown, the foldable electronic paper display device 100a includes an electronic paper display panel 110 and a rear protective sheet 120a. The difference from the embodiment of FIG. 1 is that the width W2 of the groove 122d of the rear protective sheet 120a is larger than the width of the bending area A1 of the electronic paper display panel 110, so that the entire bending area A1, the partial flat area A2 and the partial plane The area A3 is exposed by the groove 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 protective sheet 120a is smaller than the width of the bending area A1, the plane area A2 and the plane area A3 (the following inequality is A1+A2+A3 is shown), and the width W2 is greater than π R, that is, π R < W2 < A1 + A2 + A3.

Fig. 5 is a cross-sectional view showing the 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 showing the foldable electronic paper display device 100b of Fig. 5 in a folded state. Referring also to FIGS. 5 and 6, the foldable electronic paper display device 100b includes an electronic paper display panel 110 and a rear protective sheet 120b. The difference from the first and second embodiments is that the rear protective sheet 120b has two grooves 122e and 122f. Further, a portion of the groove 122e is located in the plane area A2, and a part is located in the bending area A1. A portion of the groove 122f is located in the planar area A3, and a portion is located in the bending area A1. Therefore, the boundary between the plane area A2 and the bending area A1 is exposed by the groove 122e, and the boundary between the plane area A3 and the bending area A1 is exposed by the groove 122f.

In other words, the rear protective sheet 120b 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 plane areas A2, A3, respectively. The third section 128 is located in the bending zone 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 back protection sheet 120b can have one of the grooves 122e, 122f and is not intended to limit the invention.

Fig. 7 is a cross-sectional view showing the 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 showing the foldable electronic paper display device 100c of Fig. 7 in a folded state. Referring to FIGS. 7 and 8, the foldable electronic paper display device 100c includes an electronic paper display panel 110 and a rear protective sheet 120c. The difference from the fifth and sixth embodiments is that the third section 128a of the rear protective sheet 120c further has a plurality of grooves 122g. The grooves 122g of the third sections 128a contribute to the bending of the rear protective sheet 120c and the electronic paper display panel 110, so that the electronic paper display panel 110 is not easily damaged by stress concentration, and the third section of the rear protective sheet 120c The 128a can also maintain sufficient support for the bending zone A1.

Fig. 9 is a cross-sectional view showing the 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 showing the foldable electronic paper display device 100d in a folded state in Fig. 9. Referring also to Figures 9 and 10, the foldable electronic paper display device 100d includes an electronic paper display panel 110 and a rear protective sheet 120d. The difference from the first and second embodiments is that the rear protective sheet 120d has the first portion 125, the second portion 127, and the third portion 129 which are not identical in material. The first portion 125 and the second portion 127 are located in the plane areas A2, A3, respectively. The third portion 129 is located in the bending zone A1 and extends into the planar zones A2, A3. The grooves 122h, 122i of the rear protective sheet 120d are all located in the third portion 129 of the rear protective sheet 120d.

In the present embodiment, the material of the third portion 129 of the rear protective sheet 120d is different from the material of the first portion 125. The material of the third portion 129 is also different from the material of the second portion 127, and the material of the first portion 125 is second. The material of part 127 is the same. For example, the hardness of the first portion 125 and the second portion 127 of the rear protective sheet 120d is greater than the hardness of the third portion 129, and the ductility of the third portion 129 is greater than the ductility of the first portion 125 and the second portion 127, so that the electronic paper The planar areas A2, A3 of the display panel 110 may be supported by the stiffer first portion 125 and the second portion 127, respectively, and the bend region A1 may be supported by the softer third portion 129.

In this way, the material of the third portion 129 of the protective sheet 120d and the grooves 122h and 122i therein facilitate 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 easily stressed due to stress. Damaged, and the third portion 129 of the rear protective sheet 120d can also retain sufficient support for the bending zone A1.

In this embodiment, the material of the third portion 129 of the rear protective sheet 120d may be silicone, and the material of the first portion 125 and the second portion 127 may be polyethylene terephthalate (PET), but It is not intended to limit the invention.

It should be understood that the grooves of the embodiments of the present invention may be in the form of grooves of FIGS. 3A to 3D, depending on the needs of the designer.

11 is a cross-sectional view showing the 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 showing the foldable electronic paper display device 100e in a folded state in Fig. 11. The difference from the first and second embodiments is that the groove 122j of the rear protective sheet 120e is not hollow, that is, the depth of the groove 122j is smaller than the thickness of the rear protective sheet 120e. With such a design, in the bending area A1, the position of the back surface 112 of the electronic paper display panel 110 corresponding to the groove 122j is covered by the thinner portion of the rear protective sheet 120 without being exposed from the groove 122j. The grooves of the embodiments of the present invention can be selected in the form of the grooves 122j of FIG. 11 and FIG. 12, depending on the needs of the designer.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and the present invention can be modified and modified without departing from the spirit and scope of the present invention. The scope is subject to the definition of the scope of the patent application attached.

Claims (15)

 A foldable electronic paper display device comprising: an electronic paper display panel having a bending zone and two planar regions respectively adjoining the two edges of the bending zone, wherein the electronic paper display panels are substantially folded when the electronic paper display panel is folded And a rear protective sheet on a back surface of the electronic paper display panel, and located in the planar area and the bending area, the rear protective sheet has at least one groove, and the groove is at least partially located in the curved In the fold region, the width of the groove is smaller than the width of the bend region.    The foldable electronic paper display device of claim 1, wherein the groove has a width W, the radius of curvature of the bent portion is R, and 1 mm < W < π R mm.    The foldable electronic paper display device of claim 1, wherein the groove is located at a center of the bending region.    The foldable electronic paper display device of claim 1, wherein a portion of the trench is located in the planar region, and a boundary of one of the planar regions and the bent region is exposed by the trench.    The foldable electronic paper display device of claim 1, wherein the rear protective sheet has two grooves, a portion of each of the grooves is located in the planar region, and the planar regions and the curved region are The junctions are exposed by the trenches.    The foldable electronic paper display device of claim 1, wherein the rear protective sheet has two grooves, a first segment, a second segment and a third segment, the first segment and the The second segments are respectively located in the planar regions, the third segments are located in the bending regions, and the trenches are respectively located between the first segment and the third segment and the second segment Between this third section.    The foldable electronic paper display device of claim 6, wherein the third section of the rear protective sheet further has a plurality of grooves.    The foldable electronic paper display device of claim 1, wherein the rear protective sheet has a first portion, a second portion and a third portion, wherein the first portion and the second portion are respectively located in the planar regions. The third portion is located in the bending region and extends into the planar regions, and the material of the third portion is different from the material of the first portion, and the material of the first portion is the same as the material of the second portion.    The foldable electronic paper display device of claim 8, wherein the groove is located in the third portion of the rear protective sheet.    The foldable electronic paper display device of claim 8, wherein the hardness of the first portion and the second portion is greater than the hardness of the third portion.    The foldable electronic paper display device of claim 8, wherein the third portion has a ductility greater than a ductility of the first portion and the second portion.    The foldable electronic paper display device of claim 8, wherein the third portion is made of silicone, and the first portion and the second portion are made of polyethylene terephthalate.    The foldable electronic paper display device according to claim 1, wherein the shape of the groove in a plan view is a linear shape, a chord waveform, a square waveform or a triangular waveform.    The foldable electronic paper display device of claim 1, further comprising: a front protective sheet on a front surface of the electronic paper display panel facing away from the back.    A method for manufacturing a foldable electronic paper display device includes: attaching a rear protective sheet to a back surface of an electronic paper display panel, wherein the electronic paper display panel has a bending region and respectively adjacent to the bending region a two planar region of the edge; and cutting the rear protective sheet to form at least one trench, wherein the trench is at least partially located in the bent region.