Display device and method of manufacturing the same

Abstract

The application provides a display device, which comprises a first substrate, a first alignment layer, a second substrate, a second alignment layer and a display medium. The first alignment layer is arranged on the first substrate. The second substrate is opposite to the first substrate. The second alignment layer is arranged on the second substrate, and the first alignment layer and the second alignment layer are located between the first substrate and the second substrate. The display medium is located between the first alignment layer and the second alignment layer, wherein the surface of the display medium facing the first alignment layer and the second alignment layer has irregular blocks surrounded by microstructures. In addition, the application also provides a manufacturing method of the display device.

Description

TECHNICAL FIELD

[0001] The present application relates to an optoelectronic device and a manufacturing method thereof, and in particular to a display device and a manufacturing method thereof. BACKGROUND

[0002] Reflective liquid crystal display is attracting market attention for its energy saving and environmental protection advantages. It uses the bistable characteristics of liquid crystal molecules to reflect or penetrate ambient light, thereby producing a bright state or a dark state to achieve the purpose of display, so it does not need to set up an additional backlight.

[0003] However, the current reflective liquid crystal display is white and hazy in color in the dark state, so the display quality is poor. In addition, the current reflective liquid crystal display has a long response time, so it cannot achieve active driving. SUMMARY

[0004] The present application provides a display device with improved transparency in the dark state and shortened response time.

[0005] The present application also provides a manufacturing method of a display device, which can eliminate the traditional printing process for forming an alignment layer.

[0006] One embodiment of the present application provides a display device, comprising: a first substrate; a first alignment layer disposed on the first substrate; a second substrate opposite to the first substrate; a second alignment layer disposed on the second substrate, and the first alignment layer and the second alignment layer are located between the first substrate and the second substrate; and a display medium located between the first alignment layer and the second alignment layer, wherein the surface of the first alignment layer and the second alignment layer facing the display medium has irregular blocks surrounded by microstructures.

[0007] In one embodiment of the present application, the diameter of the irregular blocks is between 20 μm and 700 μm.

[0008] In one embodiment of the present application, the thickness of the first alignment layer or the second alignment layer is less than or equal to 1 μm.

[0009] In one embodiment of the present application, the microstructure has an irregular curve shape.

[0010] In one embodiment of the present application, the length of the irregular curve is between 10 μm and 900 μm.

[0011] In one embodiment of the present application, the line width of the irregular curve is between 0.2 μm and 0.4 μm.

[0012] In one embodiment of the present application, the microstructure comprises a polymer or an oligomer.

[0013] One embodiment of the present application provides a method for manufacturing a display device, comprising: providing a panel, the panel comprising a first substrate, a second substrate, and a display medium composition, wherein the display medium composition is between the first substrate and the second substrate, and the display medium composition comprises a display medium and a polymerizable monomer; performing a heat treatment on the panel, wherein a temperature of the heat treatment is higher than a temperature at which the display medium transforms into an isotropic liquid; and performing a photo irradiation treatment on the panel after the heat treatment and after the panel is cooled down.

[0014] In one embodiment of the present application, the temperature of the heat treatment is higher than the temperature at which the display medium transforms into an isotropic liquid.

[0015] In one embodiment of the present application, the cooling rate of the panel is less than 7°C / min.

[0016] In one embodiment of the present application, the temperature of the photo irradiation treatment is between 20°C and 60°C.

[0017] In one embodiment of the present application, the photo irradiation treatment uses unpolarized light.

[0018] In one embodiment of the present application, the wavelength of the unpolarized light is between 200 nm and 450 nm.

[0019] In one embodiment of the present application, the photo irradiation energy of the photo irradiation treatment is between 50 mW / cm 2 and 200 mW / cm 2 .

[0020] In one embodiment of the present application, the time of the photo irradiation treatment is between 50 seconds and 400 seconds.

[0021] In one embodiment of the present application, the weight percentage of the polymerizable monomer in the display medium composition is between 0.2 wt% and 2.0 wt%.

[0022] In one embodiment of the present application, the polymerizable monomer comprises an acrylic group and a phenyl group.

[0023] In one embodiment of the present application, the polymerizable monomer is selected from the following compounds or combinations thereof:

[0024]

[0025] and

[0026]

[0027] To make the above features and advantages of the present application more obvious and easy to understand, the following specific embodiments are described in detail below, together with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a flow chart of a manufacturing method of a display device according to an embodiment of the present application.

[0029] Figures 2A-2C is a cross-sectional schematic diagram of a step flow of a manufacturing method of a display device according to an embodiment of the present application.

[0030] Figures 3A-3C is a crystal phase photograph of a crystallization of a display medium obtained at different cooling rates.

[0031] Figure 4 is a partial surface magnified view of a second alignment layer of a display device according to an embodiment of the present application.

[0032] Figure 5 is a particle size analysis diagram of a microstructure according to an embodiment of the present application.

[0033] Figure 6A is a microscopic photograph of a display device according to an embodiment of the present application, in which a display medium is in a homeotropic state.

[0034] Figure 6B is a microscopic photograph of a display device according to an embodiment of the present application, in which a display medium is in a planar state.

[0035] Figure 6C is Figure 6A with Figure 6B overlapping images.

[0036] Figure 6D is a microscopic photograph of a display device according to an embodiment of the present application, in which a display medium is in a focal conic state.

[0037] Figure 6E is an arrangement schematic diagram of a display medium of a display device according to an embodiment of the present application, in which the display medium is in a focal conic state. DETAILED DESCRIPTION

[0038] In the drawings, the thicknesses of layers, films, panels, regions, etc., can be exaggerated for clarity. Like reference numerals can be used to denote like elements throughout the specification and drawings. It should be understood that when a layer, film, region, or substrate is referred to as being "on" or "connected to" another layer, film, region, or substrate, it can be directly on or connected to the other layer, film, region, or substrate or intervening layers can also be present. In contrast, when an layer, film, region, or substrate is referred to as being "directly on" or "directly connected to" another layer, film, region, or substrate, there are no intervening layers present. As used herein, "connected" can mean physically and / or electrically connected. Moreover, "electrically connected" or "coupled" can be two elements exist other elements.

[0039] It should be understood that, although the terms "first," "second," "third," etc. can 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 by 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.

[0040] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0041] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, including "at least one," unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0042] Further, relative terms such as "lower" or "bottom" and "upper" or "top" can be used herein to describe one element's or another's relationship to another element(s) as illustrated in the Figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in one of the figures is turned over, elements described as being on the "lower" side of other elements would then be oriented on "upper" sides of the other elements. The exemplary term "lower" can therefore encompass both an orientation of "lower" and "upper," depending on the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as "below" or "beneath" other elements would then be oriented "above" the other elements. The exemplary term "below" or "beneath" can, therefore, encompass both an orientation of "below" and "above." The exemplary term "above" can, therefore, encompass both an orientation of "above" and "below." The exemplary term "above" or "below" can, therefore, encompass both an orientation of "above" and "below."

[0043] "about," or "substantially" as used herein include the stated value and average value within an acceptable range of deviation for the particular quantity that is being referred to, as determined by one of ordinary skill in the art. For example, "about" can mean within one or more standard deviations, or within ±30%, ±20%, ±10%, ±5%. Further, "about," "approximately," or "substantially" as used herein can select a more acceptable range of deviation or standard deviation for optical properties, etching properties, or other properties, and can not apply one standard deviation to all properties.

[0044] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0045] Exemplary embodiments are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and / or tolerances, are to be expected. Thus, embodiments described herein are not to be construed as being limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an area illustrated or described as flat can often have rough and / or nonlinear features. Moreover, sharp angles that are illustrated can be rounded. Thus, the regions illustrated in the figures are schematic

[0046] Figure 1 is a flowchart of a method of fabricating a display device in accordance with an embodiment of the present application. Figures 2A-2Cis a cross-sectional schematic diagram of a step flow of a manufacturing method of a display device according to an embodiment of the present application. The manufacturing method of the display device 10 according to an embodiment of the present application will be described below with reference to Figure 1 and Figures 2A-2C The manufacturing method of the display device 10 according to an embodiment of the present application will be described below with reference to

[0047] In the present embodiment, the manufacturing method of the display device 10 can include the following steps. First, please refer to Figure 1 and Figure 2A In step S1, a panel 100 is provided, which includes, for example, a first substrate 110, a second substrate 120, and a display medium composition MX, wherein the display medium composition MX is located between the first substrate 110 and the second substrate 120, and the display medium composition MX can include a display medium DM and a polymerizable monomer RM.

[0048] In some embodiments, the manufacturing of the panel 100 can further include forming a pixel array layer AR on the first substrate 110. Specifically, the first substrate 110 can be provided. The material of the first substrate 110 can be glass, quartz, organic polymer, or other suitable materials. Then, the pixel array layer AR can be formed on the first substrate 110 by using semiconductor process technology. The pixel array layer AR includes at least a plurality of active elements (not shown), a plurality of pixel electrodes (not shown), a plurality of data lines (not shown), and a plurality of scan lines (not shown), wherein the active element is, for example, a thin-film transistor having a source, a gate (or called a gate electrode), and a drain (or called a drain electrode), the data line can be electrically connected to the source of the active element, the scan line can be electrically connected to the gate of the active element, and the pixel electrode can be electrically connected to the drain of the active element, but not limited thereto.

[0049] In some embodiments, the manufacturing of the panel 100 can further include forming a common electrode layer CM on the second substrate 120. The material of the second substrate 120 can be similar to that of the first substrate 110, which will not be described herein. In some embodiments, a color filter layer can be formed on the second substrate 120 before forming the common electrode layer CM, so that the display device 10 has full-color display function.

[0050] The manufacturing of the panel 100 further includes preparing the display medium composition MX, for example, by mixing the display medium DM and the polymerizable monomer RM, so that the display medium composition MX includes the display medium DM and the polymerizable monomer RM. The display medium DM is, for example, a cholesteric liquid crystal.

[0051] The polymerizable monomer RM is a reactive monomer capable of undergoing a polymerization reaction under light exposure treatment. In the present embodiment, the polymerizable monomer RM can be selected from the compounds listed in Table 1 below or a combination thereof, but is not limited thereto. In some embodiments, the polymerizable monomer RM can have a non-linear structure, and the polymerizable monomer RM can have a non-rigid structure. In some embodiments, the polymerizable monomer RM can include an acrylate group and a phenyl group. In some embodiments, the polymerizable monomer RM can include two or more phenyl groups, and the phenyl groups can be connected by a rotatable functional group, such as -O-C(=O)-, but are not limited thereto.

[0052] [Table 1]

[0053]

[0054] In the present embodiment, the weight percentage of the polymerizable monomer RM in the display medium composition MX can be between 0.2 wt% and 2.0 wt%. Preferably, the weight percentage of the polymerizable monomer RM in the display medium composition MX can be between 0.2 wt% and 1 wt%, such as 0.3 wt%, 0.5 wt%, or 0.8 wt%, but is not limited thereto. The weight percentage of the polymerizable monomer RM can be dependent on other parameters, such as the time of light exposure treatment, the energy of light exposure treatment, and the like. In one implementation, the weight percentage of the polymerizable monomer RM in the display medium composition MX can be between 0.4 wt% and 1 wt%; thereby, the subsequently formed panel 100 (see FIG. 1) can have a high transmittance (such as but not limited to: 86.83%) and a low haze (such as but not limited to: 18.8%). Figure 2C

[0055] ​Next, the first substrate 110 and the second substrate 120 can be assembled together, and the display medium composition MX can be filled between the pixel array layer AR of the first substrate 110 and the common electrode layer CM of the second substrate 120. For example, a frame glue (sealant, not shown) can be coated on the pixel array layer AR of the first substrate 110, or on the common electrode layer CM of the second substrate 120. Then, the display medium composition MX can be dropped into the space surrounded by the frame glue and the pixel array layer AR or the common electrode layer CM. After that, one of the first substrate 110 and the second substrate 120 can be moved towards the other one of the first substrate 110 and the second substrate 120 under a near vacuum environment, and the first substrate 110 and the second substrate 120 can be adhered by the frame glue to seal the display medium composition MX between the pixel array layer AR of the first substrate 110 and the common electrode layer CM of the second substrate 120, and the fabrication of the panel 100 can be completed. In other words, the display medium composition MX can be filled by a one drop fill (ODF) method to fabricate the panel 100, but the present disclosure is not limited thereto. In other embodiments, the display medium composition MX can be filled by an LC injection method or other suitable methods to fabricate the panel 100.

[0056] Next, please refer to Figure 1 and Figure 2B In step S2, the panel 100 can be subjected to a heat treatment, and the temperature of the heat treatment can be higher than the temperature at which the display medium DM is transformed into an isotropic liquid. For example, the critical temperature at which the display medium DM is transformed from an anisotropic liquid to an isotropic liquid is T °C, and in the present embodiment, the temperature of the heat treatment can be higher than or equal to T °C + 20 °C, but the present disclosure is not limited thereto. Specifically, in the present embodiment, the panel 100 can be placed in an oven, and the temperature of the oven can be pre-set to be higher than the temperature at which the display medium DM is transformed into an isotropic liquid, for example, between 100 °C and 150 °C, for example, 120 °C, so that the display medium composition MX can absorb the heat energy HT supplied by the oven and be transformed into an isotropic liquid.

[0057] Next, please refer to Figure 1 and Figure 2CIn step S3, after the heat treatment of the panel 100 and after the panel 100 is cooled down, the panel 100 is subjected to a photo-treatment, i.e. a curing treatment. In particular, in the present embodiment, the panel 100 can be cooled down to a temperature below 60°C at a cooling rate of not more than 7°C / min (e.g. 5°C / min), and then subjected to a photo-treatment using the light beam LB at a temperature between 60°C and room temperature (about 20°C), e.g. 50°C. After the photo-treatment, the polymerizable monomers RM can form the first alignment layer 130 on the pixel array layer AR of the first substrate 110, and the second alignment layer 140 on the common electrode layer CM of the second substrate 120, wherein the microstructures MS are deposited on the surface 131 of the first alignment layer 130 facing the display medium DM and on the surface 141 of the second alignment layer 140 facing the display medium DM. Thus, in the method of manufacturing the display device, the printing process for forming the alignment layer in the conventional method can be eliminated.

[0058] Figures 3A-3C are photographs of the crystal phase of the display medium obtained at different cooling rates. From Figures 3A-3C it can be seen that the cooling rate affects the size of the crystal phase of the display medium. As Figure 3A shown, when the cooling rate is greater than 7°C / min (e.g. about 10°C / min), the domain size is too small, causing too much scattering in the focal conic state, and thus high haze. As Figure 3B shown, when the cooling rate is about 5°C / min, a medium-sized crystal phase can be obtained. As Figure 3C shown, when the cooling rate is about 0.5°C / min, a large-sized crystal phase with low haze can be obtained.

[0059] The light beam LB used in the photo-treatment can be non-polarized light, e.g. non-polarized ultraviolet light. In some embodiments, the wavelength of the light beam LB can be between 200 nm and 450 nm, e.g. 300 nm, 365 nm or 420 nm. In some embodiments, the energy of the light beam LB can be between 50 mW / cm 2 and 200 mW / cm 2 , e.g. 80 mW / cm 2 , 100 mW / cm 2 or 150 mW / cm 2 . In certain embodiments, the time of the photo-treatment can be between 50 seconds and 400 seconds, e.g. 100 seconds, 200 seconds or 300 seconds. In some embodiments, the total photo-treatment energy can be between 10 and 20 Joules (J), e.g. 12 J, 15 J or 18 J. The conditions of the photo-treatment are not limited to the above, and can be properly set according to actual needs.

[0060] Figure 4 is a partial enlarged schematic view of a microstructure of a display device 10 according to an embodiment of the present application. Please refer to Figure 2C and Figure 4 , the display device 10 comprises a first substrate 110, a first alignment layer 130 disposed on the first substrate 110, a pixel array layer AR between the first substrate 110 and the first alignment layer 130, a second substrate 120 opposite to the first substrate 110, a second alignment layer 140 disposed on the second substrate 120, and the first alignment layer 130 and the second alignment layer 140 are between the first substrate 110 and the second substrate 120, a common electrode layer CM between the second substrate 120 and the second alignment layer 140, and a display medium DM between the first alignment layer 130 and the second alignment layer 140, wherein the surfaces 131, 141 of the first alignment layer 130 and the second alignment layer 140 facing the display medium DM have a topography of irregular blocks BK surrounded by microstructures MS.

[0061] In the present embodiment, the microstructures MS, the first alignment layer 130 and the second alignment layer 140 can be formed by depositing and adsorbing polymerizable monomers RM on the first substrate 110 and the second substrate 120 after polymerization of the polymerizable monomers RM. The microstructures MS, the first alignment layer 130 and the second alignment layer 140 can comprise polymers, such as oligomers, formed by polymerization of the polymerizable monomers RM. The microstructures MS can protrude from the surfaces 131, 141 of the first alignment layer 130 and the second alignment layer 140, and a plurality of microstructures MS can collectively surround a plurality of irregular blocks BK. Specifically, each microstructure MS can comprise a plurality of microparticles formed by polymerization, and the plurality of microstructures MS substantially form a wall-like structure, and each irregular block BK is surrounded by the wall-like structure.

[0062] In some embodiments, the thickness of the first alignment layer 130 and the second alignment layer 140 is not greater than or and the capacitance of the first alignment layer 130 or the second alignment layer 140 is not greater than 10 μF, such as 5 μF or 8 μF, to further reduce the power consumption required to drive the display medium DM.

[0063] From Figure 4As can be seen, the microstructure MS can have an irregular curve shape, such as irregular curves C1 to C13, wherein the line length of irregular curves C1 to C13 can be between 10 μm and 900 μm, as shown in Table 2 below. For example, in this embodiment, irregular curves C1 to C13 can surround multiple irregular blocks BK, including an irregular block BK1 surrounded by irregular curves C1 to C6 and another irregular block BK2 surrounded by irregular curves C12 to C13, wherein irregular blocks BK1 and BK2 have different shapes. In addition, in some embodiments, the line width W of irregular curves C1 to C13 can be between 0.2 μm and 0.4 μm, for example, 0.3 μm. In some embodiments, the diameter D of irregular block BK can be between 20 μm and 700 μm, for example, 50 μm, 200 μm, or 500 μm.

[0064] [Table 2]

[0065]

[0066]

[0067] Figure 5 This is a particle size analysis diagram of a microstructured MS according to one embodiment of the present invention. From... Figure 5 It can be seen that the particle size of polymerizable monomer RM after polymerization is less than 1.0 μm, and is mainly distributed between 0.2 μm and 0.4 μm.

[0068] Figure 6A This is a photomicrograph of a display device 10 according to an embodiment of the present invention with the display medium DM in a hometropic state. Figure 6B This is a photomicrograph of a display device 10 according to an embodiment of the present invention with the display medium DM in a planar state (or reflective state). Figure 6C yes Figure 6A and Figure 6B Overlapping images. From Figure 6A It can be seen that the white polymer deposited after the polymerizable monomer RM is treated with light curing forms the microstructure MS2. From Figure 6B and Figure 6C It can be seen that the microstructure MS2 formed by the polymerization deposition of polymerizable monomer RM causes the planar display medium RM to exhibit a blocky swirl arrangement (locations numbered 1, 2, 5-10, 12-13 in the figure), and these microstructures MS also affect the crystal phase of the planar and focal cone display medium RM.

[0069] Figure 6Dis a micrograph of the display device 10 according to an embodiment of the present application when the display medium DM is in the focal conic state. Figure 6E is a schematic diagram of the arrangement of the display medium DM of the display device 10 according to an embodiment of the present application when the display medium DM is in the focal conic state. From Figure 6D It can be seen that the trace of the polymerizable monomer aggregation can limit the arrangement of the display medium (e.g. liquid crystal molecules) to form a very transparent state. From Figure 6E It can be seen that the display medium DM exhibits a transparent state in a fan-shaped smectic arrangement in the focal conic state.

[0070] In addition, the response time of the display medium of the display device 10 in different states was also tested, and the test results are listed in Table 3 below. From Table 3, it can be seen that, compared with the comparative example 1 which does not use any polymerizable monomer to form an alignment layer, the embodiment 1 according to the present application can significantly shorten the response time of the display medium from the homeotropic state to the planar state, and the response time from the homeotropic state to the planar state and the response time from the planar state to the homeotropic state are only 17.88 ms, thus satisfying the requirement of the active driving that the sum of the time from the homeotropic state to the planar state and the response time from the planar state to the homeotropic state should be less than 42 ms. The embodiment 2 which reduces the weight percentage of the polymerizable monomer can also achieve the requirement of the active driving that the sum of the time from the homeotropic state to the planar state and the response time from the planar state to the homeotropic state should be less than 42 ms. Preferably, the embodiments 1 and 2 can achieve the requirement of the active driving that the sum of the time from the homeotropic state to the planar state and the response time from the planar state to the homeotropic state should be less than 20 ms.

[0071] [Table 3]

[0072]

[0073] In summary, the manufacturing method of the display device of the present application can form an alignment layer by using a display medium composition containing a polymerizable monomer, thereby eliminating the printing process conventionally used to form an alignment layer, and the formed alignment layer can not only improve the transparency of the display device in the dark state, but also significantly shorten the response time of the display medium from the homeotropic state to the planar state, so that the display device of the present application can achieve active driving.

[0074] Although the present application has been disclosed with embodiments as above, it is not intended to limit the present application, and anyone skilled in the art can make some changes and modifications without departing from the spirit and scope of the present application, so the protection scope of the present application shall be subject to the scope defined by the appended claims.

[0075] Symbol explanation

[0076] 10, 20: display device

[0077] 100: panel

[0078] 110: first substrate

[0079] 120: second substrate

[0080] 130: first alignment layer

[0081] 131, 141: surface

[0082] 140: second alignment layer

[0083] AR: pixel array layer

[0084] BK, BK1, BK2: irregular block

[0085] C1-C13: irregular curve

[0086] CM: common electrode layer

[0087] D: diameter

[0088] DM: display medium

[0089] HT: thermal energy

[0090] LB: light beam

[0091] MS: microstructure

[0092] MX: display medium composition

[0093] PS: spacer

[0094] RM: polymerizable monomer

[0095] S1, S2, S3: step

[0096] W: line width

Claims

1. A display device, comprising: a first substrate; a first alignment layer disposed on the first substrate; a second substrate located opposite to the first substrate; a second alignment layer disposed on the second substrate, and the first and second alignment layers are located between the first and second substrates; and a display medium located between the first and second alignment layers, the display medium is a cholesteric liquid crystal, wherein the first and second alignment layers have irregular blocks surrounded by microstructures on a surface facing the display medium, wherein the microstructures form a city wall-like structure, and the irregular blocks are surrounded by the city wall-like structure, and the diameter of the irregular blocks is between 20 μm and 700 μm. 3.The display device of claim 1, wherein the microstructures have an irregular curve shape.

2. The display device of claim 1, wherein a thickness of the first alignment layer or the second alignment layer is less than or equal to 100 nm. 4.The display device of claim 3, wherein the irregular curve has a line length between 10 μm and 900 μm. 5.The display device of claim 3, wherein the irregular curve has a line width between 0.2 μm and 0.4 μm. 6.The display device of claim 1, wherein the microstructures comprise a polymer or an oligomer. 7.A method for manufacturing the display device of claim 1, comprising: providing a panel, the panel comprising a first substrate, a second substrate, and a display medium composition, wherein the display medium composition is located between the first and second substrates, and the display medium composition comprises a display medium and a polymerizable monomer, wherein the weight percentage of the polymerizable monomer in the display medium composition is between 0.2 wt% and 2.0 wt%; subjecting the panel to a heat treatment, wherein the temperature of the heat treatment is higher than the temperature at which the display medium turns into an isotropic liquid; and subjecting the panel to a light treatment after the heat treatment and after the panel is cooled down, wherein the cooling rate of the panel is less than 7 ℃ / min, and wherein the light treatment uses non-polarized light. 8.The method of claim 7, wherein the temperature of the light treatment is between 20 ℃ and 60 ℃. 9.The method of claim 7, wherein the wavelength of the non-polarized light is between 200 nm and 450 nm. 10.The method of claim 7, wherein the light energy of the light treatment is between 50 mW / cm2 and 200 mW / cm2. 11.The method of claim 7, wherein the time of the light treatment is between 50 seconds and 400 seconds. 12.The method of claim 7, wherein the polymerizable monomer comprises an acrylic group and a benzene ring group. 13.The method of claim 12, wherein the polymerizable monomer is selected from the following compounds or combinations thereof: ​ and

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