TWI822480B - Pixel structure and manufacturing method thereof - Google Patents

Abstract

A pixel structure and manufacturing method thereof are provided. The pixel structure includes a substrate, a light emitting element, a reflective element, a filling structure and a bank. The light emitting element is disposed over the substrate. The reflective element is disposed over the substrate. A material of the reflective element includes cholesteric liquid crystal. The filling structure is disposed between the substrate and the reflective element. The bank is disposed between the light emitting element and the reflective element to separate the light emitting element and the reflective element.

Description

Pixel structure and manufacturing method

The present invention relates to a display panel, and in particular, to a pixel structure and a manufacturing method thereof.

With the advancement of technology, display panels are commonly used in mobile phones, TV screens, automotive panels and other applications. In order to improve the quality of the display panel, in addition to including a display for general display function, the display panel may also include a decorative film disposed on the display to provide decoration. However, the decorative film may affect the image display of the monitor, reducing image clarity and reducing the overall experience of the display panel. Therefore, how to make the display panel have both clear image display and beautiful decoration is a problem that needs to be solved at present.

The present invention provides a pixel structure and a manufacturing method thereof, which combine image display and decoration functions to enhance the overall user experience.

The pixel structure of the present invention includes a substrate, a light-emitting element, a reflective element, a filling structure and a retaining wall. The light-emitting element is arranged on the substrate. The reflective element is disposed on the substrate, wherein the material of the reflective element includes cholesteric liquid crystal. The filling structure is disposed between the substrate and the reflective element. The retaining wall is disposed between the light-emitting element and the reflective element to separate the light-emitting element and the reflective element.

The manufacturing method of the pixel structure of the present invention includes the following steps. A retaining wall is formed on the base plate, wherein the retaining wall has a plurality of openings. A light-emitting element is formed in a portion of the plurality of openings. A filling structure is formed in another portion of the plurality of openings. A reflective element is formed on the filling structure and located in another part of the plurality of openings, wherein the material of the reflective element includes cholesteric liquid crystal.

Based on the above, the pixel structure of the present invention includes a light-emitting element and a reflective element. In this way, the display layer composed of the pixel structure of the present invention does not need to be attached with a decorative film, and can be used when the light-emitting element is in the non-display mode. When the light-emitting element is in the display mode, the static picture of the reflective element is presented to achieve a decorative and beautiful effect, and the clarity of the image will not be reduced due to the influence of the film on the light-emitting element.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Throughout this specification, the same reference numbers refer to the same elements. It will be understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element, or Intermediate elements may also be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements present. As used herein, "connected" may refer to physical and/or electrical connection. Furthermore, "electrical connection" or "coupling" may mean the presence of other components between the two components.

It will be understood that, although the terms "first," "second," etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited thereto. limitations of these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a "first element," "component," "region," "layer" or "section" discussed below could be termed a second element, component, region, layer or section without departing from the teachings herein.

FIG. 1 is a schematic cross-sectional view of a pixel structure according to an embodiment of the present invention. FIG. 2A is a partially enlarged cross-sectional schematic diagram of an embodiment of the region R in FIG. 1 . FIG. 2B is a partially enlarged cross-sectional schematic view of another embodiment of the region R in FIG. 1 . For clarity of illustration, the reflective element 140 is omitted from FIG. 2A and FIG. 2B .

Please refer to FIG. 1 , the pixel structure 10 includes a first substrate 100, a blocking wall 120, a light emitting element 130, a reflective element 140 and a filling structure 150. The light-emitting element 130 is disposed on the first substrate 100 . The reflective element 140 is disposed on the first substrate 100 . The material of the reflective element 140 includes cholesteric liquid crystal. The filling structure 150 is disposed between the first substrate 100 and the reflective element 140 . The retaining wall 120 is disposed between the light-emitting element 130 and the reflective element 140 to separate the light-emitting element 130 and the reflective element 140 .

The material of the first substrate 100 may be glass, quartz, organic polymer or other applicable materials, and the present invention is not limited thereto. In some embodiments, the substrate 100 is a flexible substrate, and the material of the substrate 100 is, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyester (polyester, PES), polymethylmethacrylate (PMMA), polycarbonate (PC), polyimide (PI) or other flexible materials. The first substrate 100 may include a driving circuit (not shown) to drive the light emitting element 130 or the reflective element 140 . In some embodiments, the pixel structure 10 further includes a first electrode 110 disposed on the first substrate 100 . The light-emitting element 130 or the reflective element 140 can be electrically connected to the corresponding driving circuit through the first electrode 110 . Although a whole layer of first electrode 110 is shown in FIG. 1 , this is not intended to limit the present invention. The first electrode can have a patterned design according to actual requirements.

The retaining wall 120 is provided on the first substrate 100 and the first electrode 110 . The retaining wall 120 may have multiple openings OP to form a network structure, but the present invention is not limited thereto. The retaining wall is made of organic materials, such as photoresist materials, curable resin materials or other suitable materials, and the present invention is not limited thereto. In other embodiments, the retaining wall may be made of inorganic materials, such as silicon oxide (SiO _x ), silicon nitride (SiN _x ), other oxides, other nitrides or other suitable materials. limit.

The light-emitting element 130 and the reflective element 140 are disposed in the plurality of openings OP. In this embodiment, the light-emitting element 130 includes a first light-emitting element 130a, a second light-emitting element 130b, and a third light-emitting element 130c. However, the invention is not limited thereto, and the number of the light-emitting element 130 can be adjusted according to actual needs. The first light-emitting element 130a, the second light-emitting element 130b and the third light-emitting element 130c can be separated from each other through the blocking wall 120 and emit light of different colors. For example, the first light-emitting element 130a can emit red light, and the second light-emitting element 130c can emit red light. The element 130b can emit green light, and the third light-emitting element 130c can emit blue light, but the invention is not limited thereto.

In this embodiment, the light-emitting element 130 is an organic light-emitting diode (OLED), which includes an organic light-emitting stack, such as a hole injection layer 132, a hole transport layer 134, a light-emitting layer 136, and an electron transport layer 138 in sequence. Set in the opening OP. However, the present invention does not limit the number and type of organic light-emitting stack layers, which can be adjusted according to actual needs.

The cholesteric liquid crystal in the reflective element 140 has a planar state, a focal conic state, or a homeotropic state, and its state can be changed by changes in the electric field. For example, when the cholesteric liquid crystal is in a planar state, it can reflect the incident light, and the reflective element 140 is in a reflective state. If a low electric field is applied to the cholesteric liquid crystal in the planar state, it can change to a focal conic state, so that the incident light can be reflected. If the cholesteric liquid crystal is diffused, the reflective element 140 will be in a foggy state; if a high electric field is applied to the cholesterol liquid crystal in the planar state, all the cholesterol liquid crystal molecules can be arranged vertically and converted into a vertical state, so that the incident light can penetrate, and the reflective element 140 will be in a penetrating state. state. That is to say, when the reflective element 140 is in a planar state, it can reflect the color of the reflective element 140 . When the reflective element 140 is in a focal cone state or a vertical state, the reflection is reduced and the color of the reflective element 140 is hidden.

In some embodiments, the wavelength range that the reflective element 140 can reflect can be adjusted by adjusting the pitch of the cholesteric liquid crystal, that is, the color reflected by the reflective element 140 can be adjusted.

In this embodiment, the corresponding driving circuit can be used to make the reflective element 140 in the focal conic state or the vertical state when the light-emitting element 130 is in the display mode, and when the light-emitting element 130 is in the non-display mode, the reflective element 140 is in the non-display mode. in a flat state. In this way, when the light-emitting element 130 is in the display mode, it will not be affected by the reflective element 140 and the clarity of the image will be reduced. When the light-emitting element 130 is in the non-display mode, it can present a static image of the reflective element 140 to achieve decoration and beauty. Effect.

The filling structure 150 is disposed in the opening OP and is located between the first substrate 100 and the reflective element 140 . The filling structure 150 is used to adjust the thickness of the reflective element 140 and thereby adjust the brightness of the reflective element 140 . For example, the higher the thickness of the reflective element 140, the smaller the thickness of the filling structure 150, the stronger the reflection intensity, and the brighter the reflective element 140; conversely, the lower the thickness of the reflective element 140, the smaller the thickness of the filling structure 150. High, the weaker the reflection intensity, the darker the reflective element 140. In some embodiments, the sum of the thickness of the filling structure 150 and the thickness of the reflective element 140 is substantially equal to the depth of the opening OP. The thickness of the filling structure 150 can be adjusted according to actual needs. For example, different pixel structures can have filling structures of different heights, and some pixel structures may even have no filling structure.

The material of the filling structure 150 may be a transparent insulating material (such as epoxy resin or other suitable insulating material) or a transparent conductive material (such as poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT: PSS) , copper(II) phthalocyanine, CuPc), platinum phthalocyanine (phthalocyanine platinum, PtPc) or N,N'-bis[4-(diphenylamino)phenyl]-N,N'-bis( 1-naphthyl)benzidine (N,N'-Bis[4-(diphenylamino)phenyl]-N,N'-di(1-naphthyl)benzidine, NPB-DPA), other hole injection materials or other suitable conductive materials material), the present invention is not limited thereto.

Referring to FIGS. 2A and 2B , the surface S of the filling structure 150 is a rough surface. In some embodiments, as shown in FIG. 2A , the surface S of the filling structure 150 may be convex, that is, the thickness of the filling structure 150 near the middle is greater than the thickness of the filling structure 150 near the retaining walls 120 on both sides. In other embodiments, as shown in FIG. 2B , the surface S of the filling structure 150 may be concave, that is, the thickness of the filling structure 150 near the middle is smaller than the thickness of the filling structure 150 near the retaining walls 120 on both sides. In some embodiments, the height difference H between the highest point and the lowest point of the surface S of the filling structure 150 may be between 15 nm and 120 nm. In this way, the image reflected by the reflective element 140 can be made softer to reduce the mirror feeling.

Referring to FIG. 1 , in some embodiments, the pixel structure 10 further includes a second electrode 160 and a second substrate 170 , which are sequentially disposed on the blocking wall 120 , the light-emitting element 130 and the reflective element 140 . The light-emitting element 130 is electrically connected to the first electrode 110 and the second electrode 160 . Although a whole layer of second electrode 160 is shown in FIG. 1 , this is not intended to limit the present invention. The second electrode can have a patterned design according to actual requirements.

3A to 3C are schematic cross-sectional views of a manufacturing process of a pixel structure according to an embodiment of the present invention. It must be noted here that the embodiments of FIGS. 3A to 3C follow the component numbers and part of the content of the embodiment of FIG. 1 , where the same or similar numbers are used to represent the same or similar elements, and references with the same technical content are omitted. instruction. For descriptions of omitted parts, reference may be made to the foregoing embodiments and will not be described again here.

Referring to FIG. 3A , a retaining wall 120 is formed on the first substrate 100 , wherein the retaining wall 120 has a plurality of openings OP. For example, the barrier material layer can be coated on the first substrate 100, and then the opening OP is defined through a photolithography process to form the barrier 120. In this embodiment, the plurality of openings OP include a first opening OP1, a second opening OP2, a third opening OP3 and a fourth opening OP4. In some embodiments, before forming the blocking wall 120, the first electrode 110 is first formed on the first substrate 100. That is to say, the plurality of openings OP of the retaining wall 120 may expose part of the first electrode 110 .

Please continue to refer to FIG. 3A , the light emitting element 130 is formed in a part of the plurality of openings OP (for example, in the first opening OP1 , the second opening OP2 and the third opening OP3 ). For example, an inkjet printing process can be used to sequentially form the hole injection layer 132 , the hole transport layer 134 and the light-emitting layer 136 in the first opening OP1 , the second opening OP2 and the third opening OP3 . The inkjet printing process is, for example, spraying droplets of liquid organic light-emitting material in the first opening OP1, the second opening OP2, and the third opening OP3, and then solidifying the organic light-emitting material through a vacuum drying process to form a corresponding organic light-emitting stack. One of the layers. The above-mentioned hole injection layer 132, hole transport layer 134 and light-emitting layer 136 are formed by repeating the above-mentioned inkjet printing process and curing process. Then, a vacuum thermal evaporation process can be used to form the electron transport layer 138 on the light-emitting layer 136 . In other embodiments, the hole injection layer 132, the hole transport layer 134, the light emitting layer 136 and the electron transport layer 138 can all be formed through a vacuum thermal evaporation process, but the invention is not limited thereto.

Referring to FIG. 3B , a filling structure 150 is formed in another part of the plurality of openings OP (for example, in the fourth opening OP4 ). The method of forming the filling structure 150 includes an inkjet printing process. For example, liquid filling material (not shown) can be filled into the fourth opening OP4 by spraying droplets, and then the filling material can be solidified through a vacuum drying process to form the filling structure 150 . In some embodiments, the thickness of the filling structure 150 can be adjusted by controlling the solid content ratio of the filling material, and the air extraction conditions of the vacuum drying process can be adjusted to affect the drying rate, thereby affecting the surface morphology, so that the filling structure 150 The surface of 150 has a convex surface or a concave surface (refer to Figure 2A and Figure 2B).

Referring to FIG. 3C , a reflective element 140 is formed on the filling structure 150 and located in the fourth opening OP4, where the material of the reflective element 140 includes cholesteric liquid crystal. The method of forming the reflective element 140 includes an inkjet printing process.

Then, referring to FIG. 1 , the second electrode 160 and the second substrate 170 can be disposed on the retaining wall 120 , the light-emitting element 130 and the reflective element 140 . For example, the second electrode 160 can be formed on the second substrate 170 first, and then the second substrate 170 on which the second electrode 160 is formed is attached to the blocking wall 120, the light-emitting element 130 and the reflective element 140, so that The second electrode 160 is disposed between the second substrate 170 and the blocking wall 120 , the light-emitting element 130 and the reflective element 140 .

After the above process, the production of the pixel structure 10 can be roughly completed.

FIG. 4 is a schematic cross-sectional view of a pixel structure according to another embodiment of the present invention. It must be noted here that the embodiment of FIG. 4 follows the component numbers and part of the content of the embodiment of FIG. 1 , where the same or similar numbers are used to represent the same or similar elements, and the description of the same technical content is omitted. For descriptions of omitted parts, reference may be made to the foregoing embodiments and will not be described again here.

Referring to FIG. 4 , the pixel structure 20 of this embodiment is different from the embodiment of FIG. 1 in that the light-emitting element 230 of the pixel structure 20 is a micro-light-emitting diode, which can be disposed on the first surface in a transposed manner. on electrode 110. The light-emitting element 230 includes a first light-emitting element 230a, a second light-emitting element 230b and a third light-emitting element 230c, but the present invention is not limited thereto, and the number of the light-emitting element 230 can be adjusted according to actual needs. The first light-emitting element 230a, the second light-emitting element 230b and the third light-emitting element 230c can be separated from each other through the blocking wall 120, and emit light of different colors. For example, the first light-emitting element 230a can emit red light, and the second light-emitting element 230c can emit red light. The element 230b can emit green light, and the third light-emitting element 230c can emit blue light, but the invention is not limited thereto. The light-emitting element 230 is electrically connected to the first electrode 110 but not to the second electrode 160 .

To sum up, the pixel structure of the present invention includes a light-emitting element and a reflective element. In this way, the display layer composed of the pixel structure of the present invention does not need to have a decorative film attached to it, but can have the light-emitting element on a non-displayed surface. In the display mode, the static picture of the reflective element is presented to achieve a decorative and beautiful effect, and when the light-emitting element is in the display mode, there will be no problem of reduced image clarity due to the influence of the film.

Although the present invention has been disclosed above through embodiments, they are not intended to limit the present invention. Anyone with ordinary knowledge in the technical field may make some modifications and modifications without departing from the spirit and scope of the present invention. Therefore, The protection scope of the present invention shall be determined by the appended patent application scope.

10, 20: Pixel structure

100: First substrate

110: first electrode

120: retaining wall

130, 230:Light-emitting element

130a, 230a: first light emitting element

130b, 230b: second light-emitting element

130c, 230c: The third light-emitting element

132: Hole injection layer

134: Hole transport layer

136: Luminous layer

138:Electron transport layer

140: Reflective element

150: Filling structure

160:Second electrode

170:Second substrate

H: Height difference

OP: Open your mouth

OP1: First opening

OP2: Second opening

OP3: The third opening

OP4: The fourth opening

R:Region

S: Surface

FIG. 1 is a schematic cross-sectional view of a pixel structure according to an embodiment of the present invention. FIG. 2A is a partially enlarged cross-sectional schematic diagram of an embodiment of the region R in FIG. 1 . FIG. 2B is a partially enlarged cross-sectional schematic view of another embodiment of the region R in FIG. 1 . 3A to 3C are schematic cross-sectional views of a manufacturing process of a pixel structure according to an embodiment of the present invention. FIG. 4 is a schematic cross-sectional view of a pixel structure according to another embodiment of the present invention.

10: Pixel structure

100: First substrate

110: first electrode

120: retaining wall

130:Light-emitting component

130a: first light emitting element

130b: Second light-emitting element

130c: The third light-emitting element

132: Hole injection layer

134: Hole transport layer

136: Luminous layer

138:Electron transport layer

140: Reflective element

150: Filling structure

160:Second electrode

170:Second substrate

OP: Open your mouth

R:Region

Claims (9)

A pixel structure includes: a substrate; a light-emitting element arranged on the substrate; a reflective element arranged on the substrate, wherein the material of the reflective element includes cholesteric liquid crystal; a filling structure arranged on the substrate and the reflective element; and a retaining wall disposed between the light-emitting element and the reflective element to separate the light-emitting element from the reflective element, wherein the substrate includes a driving circuit to drive the light-emitting element or The reflective element enables the light-emitting element to be in a focal conic state or a vertical state when the light-emitting element is in a display mode, and the reflective element is in a planar state when the light-emitting element is in a non-display mode. The pixel structure of claim 1, wherein the material of the filling structure includes epoxy resin, poly(3,4-vinyldioxythiophene): polystyrene sulfonic acid, copper phthalocyanine, platinum phthalocyanine or N ,N'-bis[4-(diphenylamino)phenyl]-N,N'-bis(1-naphthyl)benzidine. The pixel structure as claimed in claim 1, wherein a surface of the filling structure is convex or concave. The pixel structure of claim 1, wherein the height difference between the highest point and the lowest point of a surface of the filling structure is between 15 nm and 120 nm. The pixel structure of claim 1, wherein the light-emitting element includes an organic light-emitting diode or a micro-light-emitting diode. A method of manufacturing a pixel structure, including: forming a blocking wall on a substrate, wherein the blocking wall has a plurality of openings; forming a light-emitting element in a part of the plurality of openings; forming a filling structure in the plurality of openings; In another part of the opening; forming a reflective element on the filling structure and located in the other part of the plurality of openings, wherein the material of the reflective element includes cholesteric liquid crystal, and wherein the substrate includes a driving circuit to drive the light-emitting element Or the reflective element is such that when the light-emitting element is in a display mode, the reflective element is in a focal conic state or a vertical state, and when the light-emitting element is in a non-display mode, the reflective element is in a planar state. The method of manufacturing a pixel structure according to claim 6, wherein the step of forming the filling structure in the other part of the plurality of openings includes: filling a filling material into the plurality of openings in a droplet manner. in the other part; and use vacuum drying to form the filling structure. The method of manufacturing a pixel structure as claimed in claim 7 further includes: during the process of forming the filling structure, adjusting the vacuum drying conditions to make a surface of the filling structure become convex or concave. The method of manufacturing a pixel structure as claimed in claim 6, wherein the method of forming the reflective element includes an inkjet printing process.

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