TWI675355B - Flexible display panel - Google Patents

Abstract

A flexible display panel includes a first flexible layer, a second flexible layer, a buffer layer, and an element layer. The buffer layer is sandwiched between the first flexible layer and the second flexible layer and has a plurality of through holes, wherein the through holes extend from the first flexible layer to the second flexible layer, and the first flexible layer And the second flexible layer respectively cover two ports of each through hole. The width of each via is less than 2 microns. The element layer is disposed on the second flexible layer, wherein the second flexible layer is located between the element layer and the buffer layer.

Description

Flexible display panel

The present invention relates to a display, and more particularly to a flexible display panel.

Existing flexible display panels generally include a plurality of film layers stacked on each other, wherein the materials of these film layers are not completely the same. Some film layers are made of organic materials, while some film layers are made of inorganic materials. During the manufacturing process of the flexible display panel, different film layers of these materials will inevitably be heated, and defects such as air bubbles or warpage may occur. The above defects may damage the picture quality of the flexible display panel, so repairs are needed to eliminate the defects. If there are too many defects or cannot be eliminated, the flexible display panel must be reworked and even forced to be scrapped.

The present invention provides a flexible display panel. The first flexible layer, the second flexible layer, and the buffer layer included in the flexible display panel can help reduce or eliminate the above defects (such as bubbles or warpage).

The flexible display panel provided by at least one embodiment of the present invention includes a first flexible layer, a second flexible layer, a buffer layer, and an element layer. The buffer layer is sandwiched between the first flexible layer and the second flexible layer and has a plurality of through holes, wherein the through holes extend from the first flexible layer to the second flexible layer, and the first flexible layer And the second flexible layer respectively cover two ports of each through hole. The width of each via is less than 2 microns. The element layer is disposed on the second flexible layer, wherein the second flexible layer is located between the element layer and the buffer layer.

In at least one embodiment of the present invention, the porosity of the buffer layer is between 10% and 90%.

In at least one embodiment of the present invention, the first flexible layer and the second flexible layer are not filled in the through holes.

In at least one embodiment of the present invention, at least one of the first flexible layer and the second flexible layer fills the through holes.

In at least one embodiment of the present invention, the above-mentioned element layer has a display area, and the display area corresponds to the projection area projected by the buffer layer, and some of these through holes are distributed in the projection area.

In at least one embodiment of the present invention, the through holes are periodically distributed between the first flexible layer and the second flexible layer.

In at least one embodiment of the present invention, the shape of the buffer layer is mesh.

In at least one embodiment of the present invention, the thickness of the buffer layer is between 1000 Angstrom (Å) and 10,000 Angstrom.

In at least one embodiment of the present invention, the thickness of the first flexible layer and the thickness of the second flexible layer are substantially equal.

In at least one embodiment of the present invention, a material of the buffer layer is ceramic, metal, or alloy.

In at least one embodiment of the present invention, the material of the buffer layer is selected from the group consisting of oxide, carbide, nitride, boride, and silicide.

A flexible display panel provided by another embodiment of the present invention includes a first flexible layer, a second flexible layer, a buffer crystal layer, and an element layer. The buffer crystal layer is sandwiched between the first flexible layer and the second flexible layer, and has at least a grain boundary, wherein at least one grain boundary is connected to the first flexible layer and the second flexible layer. between. The element layer is disposed on the second flexible layer, wherein the second flexible layer is located between the element layer and the buffer crystal layer.

In at least one embodiment of the present invention, the thickness of the buffer crystal layer is between 1000 Angstroms and 10,000 Angstroms.

In at least one embodiment of the present invention, the thickness of the first flexible layer and the thickness of the second flexible layer are substantially equal.

In at least one embodiment of the present invention, the material of the buffer crystal layer is selected from the group consisting of oxide, carbide, nitride, boride, and silicide.

In at least one embodiment of the present invention, the material of the buffer crystal layer is selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), and indium gallium zinc oxide (Indium Gallium zinc). Zinc Oxide (IGZO).

Based on the above, the use of the first flexible layer and the second flexible layer can help reduce the chance of warping, and the through holes in the buffer layer and at least one grain boundary of the buffer crystal layer can help the gas to escape. To suppress the formation of air bubbles. In this way, the use of the first flexible layer, the second flexible layer, and the buffer layer can help reduce or eliminate defects such as warpage and bubbles, and thus help improve yield.

In order to make the features and advantages of the present invention more comprehensible, embodiments are described below in detail with reference to the accompanying drawings, as follows.

FIG. 1A is a schematic top view of a flexible display panel according to at least one embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view drawn along a line 1B-1B in FIG. 1A. Please refer to FIG. 1A and FIG. 1B, and refer to FIG. 1A and FIG. 1B. The flexible display panel 100 includes a first flexible layer 110, a second flexible layer 120, a buffer layer 130 a, and an element layer 140. The layer 110, the second flexible layer 120, the buffer layer 130a, and the element layer 140 are stacked on each other. The buffer layer 130a is sandwiched between the first flexible layer 110 and the second flexible layer 120, and the second flexible layer 120 is located between the element layer 140 and the buffer layer 130a. The element layer 140 is disposed on the second flexible layer 120. For example, the element layer 140 may be directly manufactured on the second flexible layer 120, but is not limited thereto. For example, the element layer 140 may be manufactured first, and then may be fixed to the second layer by using adhesive or other appropriate fixing components. Flexible layer 120.

The materials of both the first flexible layer 110 and the second flexible layer 120 may be organic materials, such as Polyimide (PI), Polyethylene Ether Phthalate, and Polyethylene Naphthalate. Polyethylene Naphthalate (PEN), Polycarbonate (PC), Polyarylate (PAR), Polyetherimide or Polyether Sulfone (PES), or above organic Any combination of materials. The first flexible layer 110 and the second flexible layer 120 may be made of the same organic material, so the materials of both the first flexible layer 110 and the second flexible layer 120 may be the same as each other. However, in at least one embodiment, the materials of both the first flexible layer 110 and the second flexible layer 120 may be different from each other, so the materials of the first flexible layer 110 and the second flexible layer 120 are not limited. Be the same. The first flexible layer 110 and the second flexible layer 120 may be formed by coating and baking. Before the baking, the coated first flexible layer 110 and the second flexible layer 120 may be fluid ( fluid), and baking can cure the first flexible layer 110 and the second flexible layer 120.

The buffer layer 130a has a plurality of through-holes H13a, wherein the through-holes H13a extend from the first flexible layer 110 to the second flexible layer 120, and the first flexible layer 110 and the second flexible layer 120 respectively cover each of the through-holes. Two ports of H13a. At least one of the first flexible layer 110 and the second flexible layer 120 may fill the through holes H13a. Taking FIG. 1B as an example, the second flexible layer 120 fills the through holes H13a, but is not limited thereto.

The element layer 140 is an image display element in the flexible display panel 100 and can display an image. For example, the element layer 140 has a display area 141. The image displayed by the element layer 140 will appear in the display area 141 for viewing by the user. The element layer 140 may be a micro light emitting diode array (Micro Light Emitting Diode Array, μLED Array) or an organic light emitting diode ( Organic LED, OLED). Since the first flexible layer 110, the second flexible layer 120, the buffer layer 130a, and the element layer 140 are stacked on each other, the display area 141 can be correspondingly projected on the first flexible layer 110, the second flexible layer 120, or the buffer layer 130a. Out of the projection area. For example, the display area 141 corresponds to the projection area P1 projected by the buffer layer 130a, as shown in FIG. 1B. Some of these through holes H13a are distributed in the projection area P1.

In the embodiment shown in FIG. 1B, the thickness T12 of the second flexible layer 120 may be greater than the thickness T11 of the first flexible layer 110, wherein the thickness difference between the thickness T12 and the thickness T11 may be approximately equal to the thickness of the buffer layer 130a. T13. The thickness T13 of the buffer layer 130a may be between 1000 angstroms and 10,000 angstroms, and the thicknesses T11 and T12 of the first flexible layer 110 and the second flexible layer 120 may be between 5 micrometers and 20 micrometers. Therefore, one of the thicknesses T11 and T12 is significantly larger than the thickness T13, and in the embodiment of FIG. 1B, the thickness T12 of the second flexible layer 120 may be similar to the thickness T11 of the first flexible layer 110.

Since the materials of both the first flexible layer 110 and the second flexible layer 120 are the same as each other, the thermal expansion coefficients of the first flexible layer 110 and the second flexible layer 120 are also the same as each other. As such, during the manufacturing process of the flexible display panel 100, the first flexible layer 110 and the second flexible layer 120 of the same material can reduce the influence of stress to help reduce the chance of warping. Secondly, since the thickness T12 of the second flexible layer 120 is similar to the thickness T11 of the first flexible layer 110, the amount of deformation caused by the heating of both the first flexible layer 110 and the second flexible layer 120 of the same material is also Will be closer to each other to more effectively reduce the chance of warping, and even eliminate warping, thereby helping to improve yield.

In this embodiment, although the materials of the first flexible layer 110 and the second flexible layer 120 are the same as each other, in other embodiments, both the first flexible layer 110 and the second flexible layer 120 are also Materials with similar or identical thermal expansion coefficients but different types can be selected. In this way, the first flexible layer 110 and the second flexible layer 120 can also achieve the effect of reducing the occurrence of warpage. Even if the thermal expansion coefficients of the first flexible layer 110 and the second flexible layer 120 are significantly different, the thickness difference between the first flexible layer 110 and the second flexible layer 120 can be used to compensate for the difference in thermal expansion coefficient To reduce the chance of warping. Therefore, the materials of the first flexible layer 110 and the second flexible layer 120 are not limited to be the same as each other, and the thicknesses of the two are also not limited to be the same as each other.

The material of the buffer layer 130a may be ceramic, metal, or alloy, and the material of the buffer layer 130a may be selected from the group consisting of oxide, carbide, nitride, boride, and silicide. For example, the material of the buffer layer 130a may be silicon dioxide, silicon nitride, indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), zirconium oxide (ZrO ₂ ), or anodization. Aluminum (Anodic Aluminum Oxide, AAO), or any combination of the above materials.

Therefore, the buffer layer 130a may be a conductor or an insulator. In addition, the buffer layer 130a may be a high-temperature-resistant porous material, wherein the porosity of the buffer layer 130a may be between 10% and 90%, and the ignition point or phase transition temperature (such as the melting point) of the buffer layer 130a Or glass transition temperature) can be greater than 500 ° C, that is, the buffer layer 130a can withstand a high temperature of at least 500 ° C.

The through hole H13a can be formed by at least one of nanoimprint lithography, electron beam lithography, and anode electrochemical reaction. Alternatively, the parameters for manufacturing the buffer layer 130a may be adjusted to form the through hole H13a. Specifically, the buffer layer 130a may be formed by using chemical vapor deposition (CVD) or physical vapor deposition (PVD), and in the process of performing chemical vapor deposition or physical vapor deposition The through-hole H13a can be formed by adjusting the flow rate of the incoming gas.

Because the through-hole H13a can be formed by nano-imprinting, electron beam etching, or adjusting the parameters of the manufacturing buffer layer 130a, the width W13 of each through-hole H13a can be less than 2 micrometers, of which 2 micrometers is difficult for existing photolithography. Reached size. In addition, all through holes H13a are completely distributed in the buffer layer 130a, and in the display area 141 corresponding to the projection area P1 projected by the buffer layer 130a, some of the through holes H13a are distributed in the projection area P1, as shown in FIG. 1B As shown.

During the manufacturing process of the flexible display panel 100, since the buffer layer 130a has these through holes H13a, and gas molecules can penetrate the second flexible layer 120, the gas generated by the buffer layer 130a during the heating process can be Dissipate from the through holes H13a and pass through the second flexible layer 120. The heating process is, for example, the second flexible layer 120, and the temperature for baking the second flexible layer 120 is greater than or equal to 200 ° C. In this way, the through holes H13a can prevent gas from being accumulated between the first flexible layer 110 and the second flexible layer 120, so as to suppress the formation of bubbles, thereby helping to improve the yield.

FIG. 1C is a schematic top view of the buffer layer in FIG. 1A, which is substantially the same as the schematic top view of the flexible display panel 100 after the element layer 140 and the second flexible layer 120 are removed. Please refer to FIGS. 1B and 1C. In this embodiment, the through holes H13a are periodically distributed between the first flexible layer 110 and the second flexible layer 120, and the shape of the buffer layer 130a is mesh. Taking FIG. 1C as an example, the through holes H13a are lattices and are arranged in an array. The opening shapes of the through holes H13a are substantially the same as each other and are rectangular, thereby forming a square mesh. Buffer layer 130a.

In addition to the buffer layer 130a shown in FIG. 1C, in other embodiments, the buffer layer may have a shape other than a grid pattern, and a plurality of through holes of the buffer layer may be periodically distributed on the first flexible layer. 110 and the second flexible layer 120, and the opening shapes of the through holes may be substantially the same, for example, the buffer layers 130b and 130c shown in FIG. 1D and FIG. 1E. In addition, in the flexible display panel 100 shown in FIG. 1B, the buffer layer 130 a may be replaced with a buffer layer 130 b or 130 c.

Please refer to FIG. 1D. The shape of the buffer layer 130b is a honeycomb mesh. The buffer layer 130b has a plurality of through holes H13b arranged periodically, and the opening shape of each through hole H13b is six. Angular. Please refer to FIG. 1E. The shape of the buffer layer 130c is a triangular mesh. The buffer layer 130c has a plurality of through holes H13c arranged periodically, and the opening shape of each through hole H13c is triangle.

Similar to the effect of the buffer layer 130a, the through holes H13b and H13c of both the buffer layers 130b and 130c can also help the gas to dissipate, and also can suppress the formation of bubbles, which can help improve the yield. In addition, it must be noted that the through hole H13a of the buffer layer 130a can also be formed by adjusting a parameter for manufacturing the buffer layer 130a, where this parameter is, for example, a flow rate of a gas to be passed. Therefore, when the buffer layer 130a is just completed, the through holes H13a are also formed at the same time. The through holes H13a may be cracks distributed aperiodically in the buffer layer 130a, so these through holes H13a may also be formed. Aperiodically distributed between the first flexible layer 110 and the second flexible layer 120, and the shapes of at least two through holes H13a are significantly different.

FIG. 2 is a schematic cross-sectional view of a flexible display panel according to another embodiment of the present invention. Please refer to FIG. 2. The flexible display panel 200 shown in FIG. 2 is similar to the flexible display panel 100 of the foregoing embodiment. For example, the flexible display panel 200 also includes a first flexible layer 110, a second flexible layer 220, a buffer layer 230, and an element layer 140. The material of the second flexible layer 220 may be the same as that of the second flexible layer 120, and the thickness T23 of the buffer layer 230 may be between 1000 angstroms and 10,000 angstroms. The buffer layer 230 also has a plurality of through-holes H23. All the through-holes H23 are also comprehensively distributed in the buffer layer 230, and the shape of the through-holes H23 may be the same as the through-holes H13a, H13b, or H13c. However, there is still a difference between the flexible display panels 200 and 100 because the first flexible layer 110 and the second flexible layer 220 are not filled in the through holes H23.

Although the first flexible layer 110 and the second flexible layer 220 are not filled in the through holes H23, the second flexible layer 220 has gas permeability, so that gas molecules can penetrate the second flexible layer 120 and Dissipate. In other words, even though these through holes H23 are not filled, the through holes H23 can also play a role in suppressing the formation of bubbles, thereby helping to improve the yield. In addition, in this embodiment, the thickness T11 of the first flexible layer 110 may be substantially equal to the thickness T22 of the second flexible layer 220. In this way, the first flexible layer 110 and the second flexible layer 220 of the same material are basically the same as each other when heated, so as to greatly reduce the occurrence of warpage, and even eliminate the warpage and improve the yield. rate.

3 is a schematic cross-sectional view of a flexible display panel according to another embodiment of the present invention. Please refer to FIG. 3. The flexible display panel 300 shown in FIG. 3 is similar to the flexible display panel 200 of the foregoing embodiment. For example, the flexible display panel 300 also includes a first flexible layer 110, a second flexible layer 220, and an element layer 140. However, there is still a difference between the flexible display panel 300 and the flexible display panel 200, which lies in the buffer crystal layer 330 included in the flexible display panel 300.

Specifically, the buffer crystal layer 330 is sandwiched between the first flexible layer 110 and the second flexible layer 220, and the element layer 140 is disposed on the second flexible layer 220, wherein the second flexible layer 220 is located on the element layer 140 and the buffer crystal layer 330. The buffer crystal layer 330 is different from the aforementioned buffer layers 130a to 130c and 230. The buffer crystal layer 330 has a crystal structure, and therefore the buffer crystal layer 330 also has at least one grain boundary B33. Taking FIG. 3 as an example, the buffer crystal layer 330 has a plurality of grain boundaries B33, and at least one of the grain boundaries B33 is communicated between the first flexible layer 110 and the second flexible layer 220. In addition, the thickness T33 of the buffer crystal layer 330 may be between 1000 angstroms and 10,000 angstroms.

The material of the buffer crystal layer 330 is selected from the group consisting of oxide, carbide, nitride, boride, and silicide. Taking oxide as an example, the material of the buffer crystal layer 330 may be selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), and indium gallium zinc oxide (IGZO), which can be used in high temperature environments. A crystal structure is formed.

Taking indium tin oxide as an example, according to Journal of Applied Physics, page 6451 (86 6451), published in 1999, H. Kim and CM Gilmore proposed that indium tin oxide films will form at high temperatures. Crystal structure, in which this crystal structure can be found using X-ray diffraction patterns. When the indium tin oxide film is in an environment of 100 ° C, a peak of the X-ray diffraction pattern appears at (400). When the indium tin oxide thin film is in an environment of 300 ° C, the X-ray diffraction pattern will have peaks at (222), (411), and (622). Therefore, the heated indium tin oxide film can have a crystal structure of (400), or (222), (411), and (622).

Since the heating process in the process of manufacturing the flexible display panel 100 may exceed 200 ° C., such as baking the second flexible layer 120, a crystal structure can be formed inside the buffer crystal layer 330 so that the buffer crystal layer 330 has crystal grains. Border B33. The grain boundary B33 can generate grain boundary diffusion. Therefore, the gas molecules can move along the grain boundary B33 by the grain boundary diffusion, and then dissipate through the second flexible layer 220. In this way, the buffer crystal layer 330 can also prevent gas from being accumulated between the first flexible layer 110 and the second flexible layer 220 to suppress the formation of bubbles, thereby helping to improve the yield.

In summary, in the flexible display panel of at least one embodiment of the present invention, the first flexible layer and the second flexible layer can help reduce the chance of warping, and the buffer layer and the buffer crystal layer can be used separately. The plurality of through holes and at least one grain boundary help the gas to escape, so as to prevent gas from being accumulated between the first flexible layer and the second flexible layer, thereby suppressing the formation of air bubbles. It can be seen that the use of the first flexible layer, the second flexible layer, and the buffer layer can help reduce or eliminate defects such as warpage and bubbles, and help improve yield.

Although the present invention has been disclosed as above with the examples, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains may make some modifications and retouching without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the appended patent application.

100, 200, 300‧‧‧ flexible display panel

110‧‧‧First flexible layer

120, 220‧‧‧Second flexible layer

130a, 130b, 130c, 230‧‧‧ buffer layer

140‧‧‧component layer

141‧‧‧display area

330‧‧‧ buffer crystal layer

B33‧‧‧grain boundary

H13a, H13b, H23‧‧‧through hole

P1‧‧‧ projection area

T11, T12, T13, T22, T23, T33‧‧‧thickness

W13‧‧‧Width

FIG. 1A is a schematic top view of a flexible display panel according to at least one embodiment of the present invention. FIG. 1B is a schematic cross-sectional view taken along the line 1B-1B in FIG. 1A. FIG. 1C is a schematic top view of the buffer layer in FIG. 1A. FIG. 1D is a schematic top view of a buffer layer in another embodiment of the present invention. FIG. 1E is a schematic top view of a buffer layer in another embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a flexible display panel according to another embodiment of the present invention. 3 is a schematic cross-sectional view of a flexible display panel according to another embodiment of the present invention.

Claims (14)

A flexible display panel includes: a first flexible layer; a second flexible layer; a buffer layer sandwiched between the first flexible layer and the second flexible layer, and has a plurality of Through holes, wherein the through holes extend from the first flexible layer to the second flexible layer, and the first flexible layer and the second flexible layer respectively cover two ports of each through hole, each The width of the through hole is less than 2 microns, and the porosity is between 10% and 90%; and an element layer is disposed on the second flexible layer, wherein the second flexible layer is located between the element layer and the buffer Between layers. The flexible display panel according to claim 1, wherein neither the first flexible layer nor the second flexible layer is filled in the through holes. The flexible display panel of claim 1, wherein at least one of the first flexible layer and the second flexible layer fills the through holes. The flexible display panel of claim 1, wherein the through holes are periodically distributed between the first flexible layer and the second flexible layer. The flexible display panel according to claim 1, wherein the buffer layer has a mesh shape. The flexible display panel according to claim 1, wherein the thickness of the buffer layer is between 1000 angstroms and 10000 angstroms. The flexible display panel of claim 1, wherein the thickness of the first flexible layer and the thickness of the second flexible layer are substantially equal. The flexible display panel according to claim 1, wherein the material of the buffer layer is ceramic, metal or alloy. The flexible display panel of claim 1, wherein the material of the buffer layer is selected from the group consisting of oxides, carbides, nitrides, borides, and silicides. A flexible display panel includes: a first flexible layer; a second flexible layer; a buffer crystal layer sandwiched between the first flexible layer and the second flexible layer, and has at least A die boundary, wherein the at least one die boundary is connected between the first flexible layer and the second flexible layer; and an element layer is disposed on the second flexible layer, wherein the second The flexible layer is located between the device layer and the buffer crystal layer. The flexible display panel of claim 10, wherein the thickness of the buffer crystal layer is between 1000 angstroms and 10000 angstroms. The flexible display panel of claim 10, wherein the thickness of the first flexible layer and the thickness of the second flexible layer are substantially equal. The flexible display panel according to claim 10, wherein the material of the buffer crystal layer is selected from the group consisting of oxide, carbide, nitride, boride, and silicide. The flexible display panel of claim 10, wherein the material of the buffer crystal layer is selected from the group consisting of indium tin oxide, indium zinc oxide, and indium gallium zinc oxide.