CN113985511A

CN113985511A - Color filter, preparation method thereof and display device

Info

Publication number: CN113985511A
Application number: CN202111304395.0A
Authority: CN
Inventors: 林佑昇; 文遥; 陈坤霖
Original assignee: Sun Yat Sen University
Current assignee: Sun Yat Sen University
Priority date: 2021-11-05
Filing date: 2021-11-05
Publication date: 2022-01-28
Anticipated expiration: 2041-11-05
Also published as: CN113985511B

Abstract

The invention discloses a color filter, a preparation method thereof and display equipment. The preparation method comprises the following steps: preparing a first structure of a master template for nanoimprinting or a second structure of the master template for transfer printing; adopting nano-imprinting equipment to imprint a first structure on a transparent substrate, and evaporating metal and removing glue on the transparent substrate with the imprinted first structure to form a color filter; or evaporating metal on the mother template for transfer printing to form a metal nano-pore structure, and peeling the metal nano-pore structure from the mother template for transfer printing and transferring the metal nano-pore structure onto a transparent substrate. The color filter in the embodiment of the invention has high resolution and simple process, is suitable for batch production, and can be widely applied to the technical field of display.

Description

Color filter, preparation method thereof and display device

Technical Field

The invention relates to the technical field of display, in particular to a color filter, a preparation method thereof and display equipment.

Background

The color filter is an important component of the liquid crystal display, and the performance requirements of the liquid crystal display on the color filter generally include two aspects of high color purity and high contrast. The traditional color filter is realized by dispersing and coating pigments and synthetic dyes on a glass substrate, and can realize the display of colors such as red, green and blue based on the selective absorption of the pigments to colored light. The traditional color filter is prepared by a pigment dispersion coating process, is difficult to manufacture a small-size (micron-scale) unit, has low resolution, and limits the application of the traditional color filter in high PPI (Pixel Density), such as devices of AR (Augmented Reality) or VR (Virtual Reality); in addition, the preparation of the traditional color filter is not economical and environment-friendly and has complex process; the above-mentioned problems have prevented color filters based on pigments and dyes from meeting the increasing demands of electronic devices.

Disclosure of Invention

In view of the above, an object of the embodiments of the invention is to provide a color filter, a method for manufacturing the color filter, and a display device, wherein the color filter has high resolution, simple process, and is suitable for mass production.

In a first aspect, an embodiment of the present invention provides a color filter, including a transparent substrate and metal nanopore structures disposed on the transparent substrate, where the metal nanopore structures are periodically arranged to form a wire grid structure, and the metal nanopore structures are nano metal structures containing nanopores.

Optionally, the transparent substrate comprises a flexible transparent substrate.

Optionally, the material of the flexible transparent substrate includes any one of polydimethylsiloxane, polymethyl methacrylate, polyethylene terephthalate, polyimide, polycarbonate, and hydrogel.

Optionally, the material of the metal nanopore structure comprises any one of gold, silver, aluminum, copper, nickel, chromium, and titanium.

In a second aspect, an embodiment of the present invention provides a display device, including the color filter described above.

In a third aspect, an embodiment of the present invention provides a method for manufacturing a color filter, where the color filter includes a transparent substrate and a metal nanopore structure disposed on the transparent substrate, and includes the following steps:

preparing a mother template for nanoimprint or a mother template for transfer printing, wherein the structure of the mother template for nanoimprint is a first structure, the structure of the mother template for transfer printing is a second structure, the first structure and the metal nanopore structure are complementary structures, and the second structure is the same as the metal nanopore structure;

adopting nano-imprinting equipment to imprint the first structure on the transparent substrate, and evaporating metal and removing photoresist on the transparent substrate imprinted with the first structure to form a color filter;

or evaporating metal on the mother template for transfer printing to form the metal nano-pore structure, and peeling the metal nano-pore structure from the mother template for transfer printing and transferring the metal nano-pore structure to the transparent substrate.

Optionally, preparing a master template for nanoimprinting or a master template for transfer printing specifically includes:

selecting a hard base material as a base material for preparing a mother template;

and photoetching by using an electron beam direct writing device to form the first structure or the second structure.

The implementation of the embodiment of the invention has the following beneficial effects: the color filter in the embodiment of the invention comprises a transparent substrate and a metal nano-pore structure arranged on the transparent substrate; the minimum size of the metal nano-pore structure can be submicron, so that the metal nano-pore structure has extremely high resolution; in addition, the metal nanopore structure is used for preparing a master template or a master template for transfer printing through electron beam direct writing equipment, and the metal nanopore structure is prepared by adopting the master template through a nanoimprint or transfer printing process, so that the color filter is prepared, the preparation process is simple, the cost is low, and the preparation method is suitable for large-area batch production.

Drawings

Fig. 1 is a schematic structural diagram of a color filter according to an embodiment of the present invention;

FIG. 2 is a filter spectrum of a color filter for RGB three primary colors according to an embodiment of the present invention;

FIG. 3 is a graph of spectral response of a color filter at different stretching ratios according to an embodiment of the present invention;

FIG. 4 is a transmission spectrum of a color filter corresponding to a substrate of different materials provided by an embodiment of the present invention;

FIG. 5 is a flowchart illustrating a method for fabricating a color filter according to an embodiment of the present invention;

fig. 6 is a schematic flow chart illustrating a process of another method for manufacturing a color filter according to an embodiment of the invention.

Detailed Description

The invention is described in further detail below with reference to the figures and the specific embodiments. The step numbers in the following embodiments are provided only for convenience of illustration, the order between the steps is not limited at all, and the execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art.

As shown in fig. 1, an embodiment of the present invention provides a color filter, including a transparent substrate 3 and metal nanopore structures 1 disposed on the transparent substrate 3, where the metal nanopore structures 1 are periodically arranged to form a wire grid structure, and the metal nanopore structures 1 are nano metal structures including nanopores 2.

It will be understood by those skilled in the art that the periodic metal nanopore structures 1 and the gaps between the metal nanopore structures 1 constitute a wire grid structure (row or column).

The working principle of the color filter is as follows: the principle that the surface plasmon interference of the periodic metal nano-pore structure 1 and the electromagnetic response between the metal nano-pore structure 1 and the medium transparent substrate 3 are color filtering is adopted; this can be understood as: the coupling process, which converts the incident electromagnetic waves into surface plasmons, is excited by the coupling between the free surface charges of the metal nanopore structure 1 and the incident electromagnetic waves at the interface of the metal nanopore structure 1 and the dielectric transparent substrate 3.

It should be noted that the metal nanopore structure in the color filter may be designed according to specific practical requirements, including but not limited to the metal nanopore structure 1 in fig. 1.

In particular, the metal material of the metal nanopore structure may provide free surface charges, thereby causing plasmon interference to the surface of the periodic metal nanopore structure and an electromagnetic response between the metal nanopore structure and the dielectric transparent substrate.

It should be noted that the design based on symmetric nanostructures in the embodiments of the present invention has polarization insensitive property, and can maintain consistent light output under incident light with various polarization angles.

Referring to fig. 2, fig. 2 is a transmittance spectrum diagram of the color filter, and it can be seen from fig. 2 that the color filter has a high transmittance for three colors of R (red), G (green), and B (blue), wherein the transmittance of the color filter for R and B is as high as about 80%, and the transmittance of the stretchable color filter for G is as high as about 60%. Thus, it can be seen that the stretchable color filter has high filtering characteristics for the three primary colors of GRB.

Specifically, in the process of applying stretching force to the flexible transparent substrate, as the size of the metal nano-pore structure is extremely small, gaps exist among pores and the linear grid part is formed by the periodic metal structure, the color filter can keep the shape perfectly and cannot be torn.

It should be noted that different metal nanopore structures are used, which also achieve the stretchable effect, and include, but are not limited to, the metal nanopore structure shown in fig. 1.

The traditional color filter is difficult to realize flexible display, and the micro-nano structure color filter in the application can keep the filtering characteristic with higher quality under a certain stretching/bending ratio.

Referring to fig. 3, fig. 3 is a graph of the transmittance spectrum of the stretchable color filter at different stretch ratios, and it can be seen from fig. 3 that when the stretch ratio is between 0% and 30%, although the spectral response is shifted, the approximate trend is closer, and the shifted spectrum is still in the RGB color range. It can be seen that at a certain stretch ratio, the output spectrum of the stretchable color filter shows only a small frequency shift, and the high-quality color response can be maintained.

Alternatively, the material of the flexible transparent substrate includes any one of Polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), polyethylene glycol terephthalate (PET), Polyimide (PI), Polycarbonate (PC), and hydrogel.

It should be noted that the flexible transparent substrate can be made of different material types, such as dielectric and semiconductor materials, and the material of the flexible transparent substrate includes but is not limited to polydimethylsiloxane, polymethyl methacrylate, polyethylene terephthalate, polyimide, polycarbonate or hydrogel.

Referring to fig. 4, fig. 4 is a graph showing transmittance spectra of different flexible substrate materials, the substrate materials include PDMS, PET (Polyethylene terephthalate), PI (Polyimide), PMMA, and PC (Polycarbonate), and it can be seen from fig. 4 that the transmittance spectra of the color filters corresponding to the substrates of different materials have substantially the same trend and a certain offset.

The implementation of the embodiment of the invention has the following beneficial effects: the color filter in the embodiment of the invention comprises a transparent substrate and a metal nano-pore structure arranged on the transparent substrate; the metal nano-pore structure can be made into the size of submicron grade at the minimum, thereby having extremely high resolution.

The embodiment of the invention also provides display equipment comprising the color filter.

Specifically, for example, the Display device is a panel Display, which is implemented by combining a color Filter with an OLED (Organic electroluminescent Display) Display module and using a coe (color Filter On encapsulation) technology. The COE technology is to directly form a Black Matrix (BM) and a Color Filter (CF) disposed along the same layer on an encapsulation thin film layer or an alignment layer in the light emitting direction of an OLED device to align a top emission display panel, that is, to directly form a Color Filter on the encapsulated OLED device by photolithography. It replaces the traditional polarizer technology, effectively reduces the reflectivity of the OLED panel, improves the color purity, increases the color gamut, reduces the thickness of the panel, and improves the brightness of the panel display.

As shown in fig. 5, an embodiment of the present invention provides a method for manufacturing a color filter, where the color filter includes a transparent substrate and a metal nanopore structure disposed on the transparent substrate, and the method includes the following steps:

s100, preparing a mother template for nanoimprint or a mother template for transfer printing, wherein the structure of the mother template for nanoimprint is a first structure, the structure of the mother template for transfer printing is a second structure, the first structure and the metal nanopore structure are complementary structures, and the second structure is the same as the metal nanopore structure.

It should be noted that the master template material is a hard substrate, which is convenient for imprinting or transfer printing.

It will be appreciated by those skilled in the art that the specific dimensional parameters of the metal nanopore structure need to be determined according to the production process.

Specifically, as shown in fig. 6, in the embodiment of the present invention, a silicon substrate is selected as a substrate of a mother template, and a generation process of a color filter includes any one of nanoimprint and transfer; the nano-imprinting process transfers the pattern of the first structure to the substrate, and then carries out metal evaporation and stripping according to the first structure on the substrate to form a color filter; the transfer printing process firstly carries out metal evaporation on the second structure to form a metal nano-pore structure, and then transfers the metal nano-pore structure to the substrate.

s110, selecting a hard base material as a base material for preparing a mother template;

and S120, photoetching through the electron beam direct writing equipment to form a first structure or a second structure.

It will be appreciated by those skilled in the art that the first structure corresponds to a master template for nanoimprinting and the second structure corresponds to a master template for transfer printing.

S200A, stamping the first structure on the transparent substrate by adopting nano-stamping equipment, and evaporating metal and removing glue on the transparent substrate stamped with the first structure to form the color filter.

Specifically, if a nano-imprint technology is adopted, after the preparation of the master template is completed, the pattern needs to be transferred to the flexible substrate, namely, a nano-imprint device is adopted to imprint the designed structure on the required flexible substrate by means of ultraviolet curing; and then, performing operations such as metal evaporation, photoresist removal and the like on the flexible substrate with the structure transferred out to finish the manufacture of the color filter.

S200B, or evaporating metal on the master template for transfer printing to form the metal nanopore structure, peeling the metal nanopore structure from the master template for transfer printing and transferring to the transparent substrate.

Specifically, if a direct transfer scheme is adopted, a metal structure should be evaporated on the mother template; then, the mother template coated with the metal by evaporation is bonded with a flexible substrate or is attached together by a method of configuring the flexible substrate on the mother template by using solution, and the metal is peeled off from the mother template and transferred to the flexible substrate by using the difference of the adhesion force between the metal and the Si-based mother template and the flexible substrate, so that the preparation of the color filter is realized.

While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The color filter is characterized by comprising a transparent substrate and metal nano-pore structures arranged on the transparent substrate, wherein the metal nano-pore structures are periodically arranged to form a wire grid structure, and the metal nano-pore structures are nano-metal structures containing nano-pores.

2. The color filter according to claim 1, wherein the transparent substrate comprises a flexible transparent substrate.

3. The color filter according to claim 1, wherein the material of the flexible transparent substrate comprises any one of polydimethylsiloxane, polymethyl methacrylate, polyethylene terephthalate, polyimide, polycarbonate, and hydrogel.

4. The color filter according to claim 1, wherein the material of the metal nano-pore structure comprises any one of gold, silver, aluminum, copper, nickel, chromium, and titanium.

5. A display device comprising the color filter according to any one of claims 1 to 4.

6. A method for preparing a color filter, wherein the color filter comprises a transparent substrate and a metal nanopore structure disposed on the transparent substrate, comprising:

7. The method according to claim 6, wherein preparing the master template for nanoimprinting or the master template for transfer printing specifically comprises: