Abstract:
A wire grating polarizing film ( 20 ) and a manufacturing method therefor, and a display apparatus, wherein the manufacturing method of the wire grating polarizing film ( 20 ) comprises: coating a mixture ( 100 ) of a polymer monomer ( 101 ) and metal particles ( 102 ) on the surface of an underlayer substrate ( 01 ); curing the mixture ( 100 ) at a pre-set position; and forming a wire grating pattern comprising bulges ( 110 ) arranged at intervals at the surface of the underlayer substrate ( 01 ). The manufacturing method can solve the problems of complex process, large difficulty and high cost in the manufacturing process of the wire grating polarizing film ( 20 ).

Description:
TECHNICAL FIELD 
       [0001]    At least one embodiment of the present disclosure relates to a wire grid polarizer and a fabrication method thereof, and a display device. 
       BACKGROUND 
       [0002]    Thin Film Transistor Liquid Crystal Display (TFT-LCD), as a flat-panel display device, is more frequently applied to high-performance display field, due to its characteristics such as small size, low power consumption, no radiation and relatively low fabrication cost. 
       SUMMARY 
       [0003]    Embodiments of the present disclosure provide a wire grid polarizer and a fabrication method thereof, and a display device, to solve problems of a complicated process, great difficulty and high cost in a fabrication process of the wire grid polarizer. 
         [0004]    According to one aspect of the embodiments of the present disclosure, there is provided a fabrication method of a wire grid polarizer, comprising: applying a mixture including a polymeric monomer and a metal particle on a surface of a base substrate; performing a curing treatment on the mixture at a predetermined position; and forming a wire grid pattern including protrusions arranged at intervals on the surface of the base substrate. 
         [0005]    According to another aspect of the embodiments of the present disclosure, there is provided a wire grid polarizer, comprising: a base substrate; and protrusions arranged at intervals on a surface of the base substrate; and the protrusion including a resin material doped with a metal particle. 
         [0006]    According to still another aspect of the embodiments of the present disclosure, there is provided a display device, comprising the wire grid polarizer as described above. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    In order to more clearly illustrate the technical solution of the embodiments of the present disclosure, the drawings of the embodiments will be briefly described in the following; it is obvious that the described drawings are only related to some embodiments of the present disclosure and thus are not limitative of the present disclosure. 
           [0008]      FIG. 1 a    is a structural schematic view of a display device; 
           [0009]      FIG. 1 b    is a structural schematic view of a wire grid polarizer; 
           [0010]      FIG. 2  is a flow chart of a fabrication method of a wire grid polarizer provided by embodiments of the present disclosure; 
           [0011]      FIG. 3  is a flow chart of another fabrication method of the wire grid polarizer provided by the embodiments of the present disclosure; 
           [0012]      FIGS. 4 a  to 4 c    are structural schematic views in the fabrication process of the wire grid polarizer provided by the embodiments of the present disclosure; 
           [0013]      FIG. 5  is a flow chart of another fabrication method of the wire grid polarizer provided by the embodiments of the present disclosure; and 
           [0014]      FIG. 6  is a structural schematic view in the fabrication process of the wire grid polarizer provided by the embodiments of the present disclosure; 
       
    
    
     REFERENCE SIGNS 
       [0015]      01 —base substrate;  10 —array substrate;  11 —color filter substrate;  12 —liquid crystal layer;  13 —first polarizer;  14 —backlight module;  15 —second polarizer;  20 —wire grid polarizer;  100 —mixture;  101 —polymeric monomer;  102 —metal particle;  110 —protrusion;  201 —mask; A—light-transmissive region of mask; B—light-shielding region of mask;  202 —stamping die. 
       DETAILED DESCRIPTION 
       [0016]    In order to make objects, technical details and advantages of the embodiments of the present disclosure apparent, the technical solutions of the embodiment will be described in a clearly and fully understandable way in connection with the drawings related to the embodiments of the present disclosure. It is obvious that the described embodiments are just a part but not all of the embodiments of the present disclosure. Based on the described embodiments in the present disclosure, those skilled in the art can obtain other embodiment(s), without any inventive work, which should be within the scope of the present disclosure. 
         [0017]    A TFT-LCD, as shown in  FIG. 1   a,  comprises an array substrate  10  and a color filter substrate  11 . A liquid crystal layer  12  is filled between the array substrate  10  and the color filter substrate  11 . In addition, a first polarizer  13  is provided on an upper surface of the color filter substrate  11 , and a second polarizer  15  is provided between the array substrate  10  and a backlight module  14 , and an optical axis of the first polarizer  13  and an optical axis of the second polarizer  15  are perpendicular to each other. In the case that no electric field is applied to the liquid crystal layer  12 , light emitted from the backlight module  14  is incident on the liquid crystal layer  12  through the second polarizer  15 , the light is rotated by the liquid crystal molecules of the liquid crystal layer  12  during traveling through the liquid crystal layer  12 , and then the light is emitted from the first polarizer  13 . In the case that an electric field is applied to the liquid crystal layer, an arrangement direction of the liquid crystal molecules in the liquid crystal layer  12  changes, so that the incident light cannot pass through the TFT-LCD. In this way, intensity of light emitted from the TFT-LCD can be controlled. In addition, under a filtering effect of the color filter substrate  11 , color image display can be implemented. 
         [0018]    In the case shown in  FIG. 1   a,  the above-described polarizers (the first polarizer  13  and the second polarizer  14 ) may be made of a polyvinyl alcohol (PVA) film. The polarizer allows one polarization component in natural light to transmit, while the other polarization component is absorbed by the polarizer. As a result, a lot of light loss will be caused, so that utilization of the light from the backlight module  14  is greatly reduced. 
         [0019]    In order to solve the above-described problem, a wire grid polarizer  20  made of a metal material is employed, as shown in  FIG. 1   b.  In the case that light is incident on the wire grid polarizer  20 , under an oscillatory action of free electrons on a surface of the metal wire grid polarizer  20 , almost all light having an electric field vector component parallel to the wire grid is reflected, and almost all light having an electric field vector component perpendicular to the wire grid is transmitted. In addition, the light reflected by the wire grid polarizer  20  can be reused. Thus, the utilization of light is effectively improved. 
         [0020]    However, in a process of fabricating the above-described metal wire grid polarizer  20 , it is necessary to form a metal layer by using a metal target material, and it is also necessary to pattern the metal layer to form the pattern of the wire grid polarizer  20  by a relatively highly accurate etching process. Therefore, the fabrication process thereof is complicated, with great processing difficulty and high fabrication cost. 
         [0021]    Embodiments of the present disclosure provide a fabrication method of a wire grid polarizer. As shown in  FIG. 2 , the method, for example, includes step S 101  to step S 103 , which will be described below one by one. 
         [0022]    Step S 101 : applying a mixture  100  including a polymeric monomer  101  and a metal particle  102  on a surface of a base substrate  01 , as shown in  FIG. 4   a.    
         [0023]    For example, the mixture  100  is coated on the surface of the base substrate  01 . 
         [0024]    For example, the base substrate  01  is formed by at least one of glass and quartz. For example, in the case that the wire grid polarizer is employed in a flexible display panel, the base substrate  01  is formed by at least one of polyethylene terephthalate (PET) and cellulose triacetate (TAC), to meet design requirements that the flexible display panel can be bent and convoluted. 
         [0025]    Step S 102 : performing a curing treatment on the mixture  100  at a predetermined position. 
         [0026]    Step S 103 : forming a wire grid pattern including protrusions  110  arranged at intervals on the surface of the base substrate  01 . 
         [0027]    The embodiments of the present disclosure are not limited to the sequence of the above-described steps. For example, the curing treatment on the mixture may be performed first, followed by forming the wire grid pattern; or, forming the wire grid pattern may be performed first, followed by the curing treatment. 
         [0028]    The embodiments of the present disclosure provide the fabrication method of the wire grid polarizer, comprising: applying the mixture including the polymeric monomer and the metal particle on the surface of the base substrate; performing the curing treatment on the mixture at the predetermined position, so that the polymeric monomer at the predetermined position is cured; and forming the wire grid pattern including the protrusions arranged at intervals on the surface of the base substrate. For example, the cured mixture at the predetermined position is reserved on the base substrate, and substance at other positions is removed, so that the wire grid pattern including the protrusions arranged at intervals is formed on the surface of the base substrate. For example, each protrusion includes cured polymeric monomer and the metal particle encapsulated in the cured polymeric monomer. Thus, according to one aspect of the embodiments of the present disclosure, since the polymeric monomer is generally made of a resin material, it has a lower cost compared to a metal target material. According to another aspect of the embodiments of the present disclosure, since the above-described protrusions arranged at intervals have the metal particle, the incident light is polarized by utilizing an oscillation characteristic of the free electrons in the metal particle, so that the wire grid polarizer having a reflection characteristic is formed. According to still another aspect of the embodiments of the present disclosure, in the above-described process of fabricating the wire grid polarizer, compared to the case of using the metal target material, no metal deposition process and etching process is adopted, and thus, the fabrication process is simple, with low consumption of the metal material. 
         [0029]    For example, the above-described polymeric monomer  101  includes an acrylic monomer, for example, at least one or a combination of several of methyl acrylate, ethyl acrylate, n-butyl acrylate, methyl methacrylate, and n-butyl methacrylate. 
         [0030]    For example, the curing treatment according to the embodiments of the present disclosure refers to that, under actions of heat, pressure, a curing agent and/or ultraviolet light, the polymeric monomer  101  undergoes a chemical reaction and chemical bonds are generated between linear molecules of the polymeric monomer  101 , so that the linear molecules are linked together to form a network structure, and the polymeric monomer  101  is cross-linked and cured to form an insoluble and infusible material. In the case that the above-described curing treatment is performed on the polymeric monomer formed of the acrylic monomer, an acrylic polymer is formed. The following embodiments of the present disclosure are illustrated with the curing treatment using an ultraviolet irradiation process as an example. 
         [0031]    For example, the above-described metal particle includes at least one or a combination of several of an aluminum particle, an aluminum alloy particle, a copper particle and an iron particle. A conductive property of metal aluminum is stronger, so the metal aluminum contains more free electrons. The wire grid polarizer according to the embodiments of the present disclosure achieves the polarization of the incident light just by using the oscillation characteristic of the free electrons in the metal. Therefore, the metal particle according to the embodiments of the present disclosure preferably is the aluminum particle or the aluminum alloy particle. 
         [0032]    For example, the wire grid polarizer  20  having the wire grid pattern needs to achieve the polarization of the incident light. In this case, for the protrusions  110  of the above-described wire grid pattern, a period T thereof (a distance between centers of two adjacent protrusions  110 ) needs to be less than or equal to a half of the wavelength of the incident light. 
         [0033]    In addition, the above-described predetermined position is a position of the protrusions  110  to be formed, and the position of the protrusions  110  is related to the incident light. That is, the predetermined position is set according to the incident light. For example, in the case that the incident light is visible light, since the wavelength of the visible light is 400 to 800 nm, the period T of the protrusions  110  is less than or equal to 200 nm, and then the predetermined position is set according to the period T (i.e., the distance between the centers of the adjacent two protrusions  110 )≦200 nm. For another example, in the case that the above-described wire grid polarizer is used in an infrared camera, since the wavelength of the infrared light as the incident light is 760 nm to 1 mm, the period T of the protrusions  110  is less than or equal to 380 nm, and then the predetermined position is set according to the period T≦380 nm. 
         [0034]    On the premise that it is ensured that the wire grid polarizer works normally, the period T of the protrusions  110  is preferably as small as possible. However, the smaller the period T of the protrusions  110 , the higher the fabrication accuracy, and the greater the processing difficulty. Thus, in overall consideration of the process difficulty and the polarization effect, the period T of the protrusions  110  according to the embodiments of the present disclosure is less than or equal to 100 nm. 
         [0035]    The fabrication method of the above-described wire grid polarizer will be described in details with reference to specific examples below. 
       EXAMPLE ONE 
       [0036]    S 201 : applying a mixture  100  of an acrylic monomer and an aluminum particle on a surface of a base substrate  01 , as shown in  FIG. 3  and  FIG. 4   a.    
         [0037]    For example, a thickness of the mixture  100  ranges from 20 nm to 100 nm, including end values of 20 nm and 100 nm. In one aspect, in the case that the thickness of the mixture  100  is less than 20 nm, a height difference between the formed protrusion  110  and the base substrate  01  is too small, so that the fabricated wire grid polarizer may not polarize the incident light. In another aspect, in the case that the thickness of the mixture  100  is more than 100 nm, the thickness of the wire grid polarizer is too great, so that the prepared display device can not satisfy a trend of ultra-thinning 
         [0038]    S 202 : providing a mask  201  on a surface of the mixture  100 , and performing an ultraviolet exposure on a portion of the mixture  100  corresponding to a light-transmissive region A of the mask  201 , as shown in  FIG. 4   b.    
         [0039]    For example, a width of the light-transmissive region A of the mask  201  is less than or equal to 50 nm. Thus, a width of the fabricated protrusion  110  is less than or equal to 50 nm, so that the polarization effect of the wire grid polarizer is better. 
         [0040]    In addition, the mask  201  further includes a light-shielding region B that does not transmit light. Thus, as shielded by the light-shielding region B, a portion of the mixture  100  corresponding to the light-shielding region B is not cured by the ultraviolet exposure. 
         [0041]    S 203 : removing the portion of the mixture  100  corresponding to the light-shielding region B of the mask  100 , so as to form the wire grid pattern including the protrusions  110  arranged at intervals, as shown in  FIG. 4   c.    
         [0042]    For example, the portion of the mixture  100  corresponding to the light-shielding region B of the mask  100  is not cured and still presents fluidity, so the substrate after completion of step S 202  is washed with water. 
       EXAMPLE TWO 
       [0043]    S 301 : applying a mixture  100  (as shown in  FIG. 4 a   ) of an acrylic monomer and an aluminum particle on a surface of a base substrate  01 , as shown in  FIG. 5 . 
         [0044]    For example, a thickness of the mixture  100  ranges from 20 nm to 100 nm, including end values of 20 nm and 100 nm. In one aspect, in the case that the thickness of the mixture  100  is less than 20 nm, a height difference between the formed protrusion  110  and the base substrate  01  is too small, so that the fabricated wire grid polarizer may not polarize the incident light. In another aspect, in the case that the thickness of the mixture  100  is more than 100 nm, the thickness of the wire grid polarizer is too great, so that the prepared display device can not satisfy a trend of ultra-thinning 
         [0045]    S 302 : stamping a stamping die  202  into the mixture  100  so that the stamping die  202  contact the base substrate  01 , as shown in  FIG. 6 . In this way, the mixture  100  is filled into a groove of the stamping die  202 . 
         [0046]    For example, a width of the groove of the stamping die  202  is less than or equal to 50 nm. Thus, a width of the fabricated protrusion  110  is less than or equal to 50 nm, so that the polarization effect of the wire grid polarizer is better. 
         [0047]    S 303 : performing an ultraviolet exposure on the mixture  100  in the stamping die  202 . 
         [0048]    For example, the stamping die  202  is made of a light-tight material, and in this case, as shown in  FIG. 6 , the ultraviolet exposure is performed on the mixture  100  in the groove of the stamping die  202  from a side of the base substrate  01  away from the stamping die  202 . 
         [0049]    Alternatively, for example, the above-described stamping die  202  is made of a transparent material. In this case, not only the exposure can be performed on the mixture  100  in the groove of the stamping die  202  from the side of the base substrate  01  away from the stamping die  202 , but also a light source can be provided on an upper surface of the stamping die  202 . In addition, since the stamping die  202  transmits light, light further enters into the stamping die  202  and penetrates a sidewall of the groove of the stamping die  202 , to perform curing treatment on the mixture  100  located in the groove, so that a contact surface of the mixture  100  in the groove with ultraviolet light is increased, which reduces time for curing with ultraviolet light and improves production efficiency. 
         [0050]    S 304 : separating the stamping die  202  from the mixture  100  and the base substrate  01  to form the wire grid pattern including the protrusions  110  arranged at intervals, as shown in  FIG. 4   c.    
         [0051]    Compared to Example One, in Example Two, the mixture  100  between two adjacent protrusions  110  to be formed has been extruded in the stamping process, and thus it is not necessary to perform step S 203  to remove the uncured mixture  100  in Example One, so that it is possible to avoid partial residue of the uncured mixture  100  due to a defect in the removing process in the case that the uncured mixture  100  is removed. However, in Embodiment Two, it is also necessary to clean the mixture  100  extruded during the stamping process to avoid contamination of the wire grid polarizer. Therefore, according to actual needs, the method for fabricating the wire grid polarizer is selected. 
         [0052]    The above is only illustration of the fabrication process of the wire grid polarizer. Other fabrication methods will not be repeated one by one herein, which however should fall into the protection scope of the present disclosure. 
         [0053]    Embodiments of the present disclosure provide a wire grid polarizer  20 . As shown in  FIG. 4C , the wire grid polarizer  20  comprises: a base substrate  01 , and protrusions  110  arranged at intervals on a surface of the base substrate  01 . In the embodiments of the present disclosure, the protrusion  110  includes a resin material doped with a metal particle  102 . 
         [0054]    For example, the resin material includes an acrylic polymer. The acrylic polymer for example is formed by polymerizing an acrylic monomer. The acrylic monomer for example includes at least one or a combination of several of methyl acrylate, ethyl acrylate, n-butyl acrylate and methyl methacrylate, and n-butyl methacrylate. 
         [0055]    For example, the metal particle  102  includes at least one or a combination of several of an aluminum particle, an aluminum alloy particle, a copper particle and an iron particle. A conductive property of metal aluminum is stronger, so the metal aluminum contains more free electrons. The wire grid polarizer according to the embodiments of the present disclosure achieves the polarization of the incident light just by using the oscillation characteristic of the free electron in the metal. Therefore, the metal particle according to the embodiments of the present disclosure preferably is the aluminum particle or the aluminum alloy particle. 
         [0056]    Embodiments of the present disclosure provide the wire grid polarizer, which comprises: the base substrate and protrusions arranged at intervals on the surface of the base substrate. The protrusion includes the resin material doped with the metal particle. In the way, in one aspect, compared to a metal target material, it has a lower cost; in another aspect, since the above-described protrusions arranged at intervals have the metal particles, by utilizing an oscillation characteristic of free electrons in the metal particle, the incident light is polarized, and the wire grid polarizer having a reflection characteristic is formed. Therefore, compared to use of the metal target material, the embodiments of the present disclosure lowers consumption of the metal material, so as to reduce the fabrication cost. 
         [0057]    Embodiments of the present disclosure provide a display device, comprising any one of the wire grid polarizers as described above. The display device has a same advantageous effect as that of the wire grid polarizer according to the foregoing embodiments. Since the structure, the fabrication method and the advantageous effect of the wire grid polarizer have been described in detail in the foregoing embodiments, they will not be repeated here. 
         [0058]    It should be noted that in the embodiments of the present disclosure, the display device, for example, at least comprises a liquid crystal display device and an organic light emitting diode display device; for example, the display device is any product or part having a display function such as a liquid crystal display, a liquid crystal television, a digital photo frame, a cell phone or a tablet personal computer and so on. 
         [0059]    The foregoing embodiments merely are exemplary embodiments of the present disclosure, and not intended to define the scope of the present disclosure, and the scope of the present disclosure is determined by the appended claims. 
         [0060]    The present application claims priority of Chinese Patent Application No. 201410554865.2 filed on Oct. 17, 2014, the disclosure of which is incorporated herein by reference in its entirety as part of the present application.