TW201227003A - Polarizer - Google Patents

Abstract

A polarizer including a polymer substrate and a plurality of metal nano-wires is provided. Molecules of the polymer substrate have a main arranging direction. Alternatively, surface of the polymer substrate has a plurality of micro stretches substantially parallel to the main arranging direction. The metal nano-wires are arranged on the surface of the polymer substrate and substantially parallel to the main arranging direction. The polarizer is cheap and can have big size.

Description

201227003

± jj^^uu48TW 35908twf.doc/I VI. Description of the Invention: [Technical Field] The present invention relates to a polarizing plate, and more particularly to a polarizing plate which utilizes a nanowire to produce a polarization effect. [Prior Art] The polarizing plate is widely used in many optoelectronic products because it allows a passing light to have a specific polarization state. Polarizers can be classified into the following types according to their principle of action. The first is to use a multilayer film interferometry to penetrate light of a particular linear polarization and reflect light that is orthogonal to the direction of linear polarization. The second type is a wire-grid polarizer, which mainly illuminates light by periodically arranging parallel lines of metal wires, and the light having the direction of linear polarization and the direction of alignment of the metal wires can be reflected by 'or vice versa. The third type is a film made of a cholesteric liquid crystal material, which is reflected when the circular polarization state of the light is aligned with the cholesteric liquid crystal, and vice versa. Take

The patents of Nitto, Philips and MRL are represented. The fabrication of the first and second partial polarizers requires a nanometer-scale process capability, and the fabrication process is complicated and it is not easy to produce a large-area polarizer. The optical performance of the third polarizer is excellent. However, the cost of the liquid crystal material is high and the alignment direction of the liquid crystal molecules is not easily controlled. In 1969, c〇rning of the United States first disclosed the patent No. GB 1276548 A, which used a doped metal oxide substrate and added silver halide silver particles to the substrate. By heating the stretched glass substrate to form an ellipsoidal silver particle (length to short axis ratio of 2:1 to 5:1) 3 201227003

Rj^yyuu^8TW 35908twf.doc/I The non-isotropic light absorption rate, in order to achieve the polarization of the halide particles will absorb the polarization direction and its long square. Since the metal is an absorbing polarizer, the extinction ratio is about 1 〇〇. The parallel light, the toilet year, the patent number US 7570424, has a two-layer structure of nanowire grid polarizer, the road side. However, the patented nanowire grid is formed by using a micro-film gas ratio, which is extremely expensive, and difficult to make a large-sized partial/twisted private formation.

U.S. Patent No. 3,610,729 discloses the use of birefringent materials and isotropic materials or double-refractive material multilayer film structures to reflect the refractive index of a particular polarization state. Wherein, the thickness of each layer of film and the refractive product are the quarter-wavelength of the reflected light. But not only is the cost high, but the yield is also low. SUMMARY OF THE INVENTION It is possible to solve the problem that the conventional polarizing plate is expensive and the present invention provides a problem that the polarizing plate is not easily enlarged. The polarizing plate of the present invention comprises a polymer substrate and a plurality of nano metal wires. The molecules of the polymer substrate have a main alignment direction. Alternatively, the surface of the high molecular substrate has a plurality of microchannels substantially parallel to the main alignment direction. The nanowires are arranged on the two faces of the polymer base substantially in parallel with the main alignment direction. In an embodiment of the present invention, the material of the polymer substrate is polyvinyl alcohol (P〇lyVinyl alc〇h〇1, PVA), polyg (such as ρΕτ) or 201227003 l, ^iyyu 〇48TW 3590Stwf.docA Polyimide (PI). In an embodiment of the present invention, the polymer substrate described above is stretched during the production process so that the molecules of the polymer substrate have a main alignment direction. In an embodiment of the invention, the surface of the above-mentioned polymer substrate has a micro-groove by rubbing. In an embodiment of the invention, the material of the nanowire is silver.

In one embodiment of the invention, the nanowires comprise from 50% to 1% by weight of the surface area of the polymeric substrate. In one embodiment of the invention, the nanowires comprise from 85% to 95% of the surface area of the polymeric substrate. In an embodiment of the invention, the angle between the ith nanowire and the main alignment direction is θί, η is the number of nanowires, ^ 3 cos2 θ ~ 1 s = Bu 1 2n , and S20 .5. In an embodiment of the invention, the polarizing plate has a suitable wavelength, and the line width of each of the nanowires is less than or equal to a suitable wavelength. In one embodiment of the present invention, the polarizing plate has a suitable wavelength, and the length of each of the nanowires is greater than or equal to the applicable wavelength. In an embodiment of the present invention, the polarizing plate is further included. The bright layer is disposed on the polymer core and covers the nanowire. The above-described features and advantages of the present invention can be further exemplified by a simple and inexpensive process for producing a polarizing plate of a large size: Vent

201227003 P53990048TW 35908twf.doc/I [Embodiment] FIG. 1 is a schematic view of a polarizing plate according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the polarizing plate of FIG. 1. Referring to FIG. 1 and FIG. 2, the polarizing plate 100 of the present embodiment includes a south molecular substrate 110 and a plurality of nanowires 120. The molecules of the south molecular substrate 11〇 have a main alignment direction Di〇. The nanowires 120 are arranged on the surface of the polymer substrate 110 substantially in parallel with the main array direction D10. Since most of the nanowires 12〇 are arranged in parallel with the main alignment direction D10, the light having a linear polarization direction perpendicular to the main alignment direction d1〇 can pass through the polarizing plate 1〇〇, and the linear polarization direction is parallel to the main alignment direction D10. The light will be reflected by the polarizer 1〇〇. In the polarizing plate 1 of the present embodiment, since the molecules of the polymer substrate 11 () originally have the main alignment direction D10, the nanowires 120 are naturally arranged in the main array direction D10. As a result, the manufacturing cost of the polarizing plate 1 of the present embodiment can be reduced, and the polarizing plate 100 of the present embodiment can be easily applied to a large-sized product because it can be easily enlarged. The material of the polymer substrate 110 of the present embodiment may be polyvinyl alcohol, polyester, polyimine or other polymer materials. In order to allow the molecules of the polymer substrate no to be in the main alignment direction D10 as much as possible, the polymer substrate 11 () can be stretched during the production process of the polymer substrate 110. Further, the material of the nanowire 120 of the present embodiment is silver or other metal. The nanowire 120 is formed on the polymer substrate 110 by chemical reaction or physical deposition. The quality of the polarizer can be expressed by the extinction ratio. The extinction ratio is eWTu, where Τι is the transmittance of light indicating that the direction of linear polarization is perpendicular to the direction in which the nanowires are arranged, and η is the row indicating the direction of linear polarization and the line of nanowires.

201227003 P53990048TW 35908twf.doc/I The transmittance of light perpendicular to the column direction. In order to obtain a better extinction ratio, the nanowire 120 is preferably 50% to 1 Å/Å of the surface area of the jfj molecular substrate 110, and the nanowire 120 is 85% of the surface area of the polymer substrate 11〇. % to 95% is better. In other words, the more the nanowires 12 are distributed on the surface of the polymer substrate 11A, the better the extinction ratio will be. In addition, whether or not the nanowire 120 is parallel to the main array direction D10 also affects the extinction ratio of the polarizing plate 100. Here, an index s is provided to indicate the extent to which the nanowire 120 of the polarizing plate 100 is parallel to the main array direction D10. Assuming that the number of nanowires 120 is η ' and the angle between the i-th nanowire 120 and the main alignment direction D10 is 0, then yi 3 COS2 θ -1 S=^ —~—. When S = 1, it means that all the nanowires 丨2〇 are parallel to the main alignment direction D10, and in the case of S20.5, the extinction ratio of the polarizing plate 100 is as high as available. The purpose of the "nano" in the name of the nanowire 12 of the present embodiment is that the line width of each of the nanowires 120 is nanometer. The polarizing plate 100 of the present embodiment has a suitable wavelength, and the line width of each of the nanowires 12 is less than or equal to the applicable wavelength, and the length of each of the nanowires 12 is more than four times ten times the applicable wavelength. Figure 3 is a cross-sectional view showing a polarizing plate of another embodiment of the present invention. Referring to FIG. 3, the polarizing plate 2 of the present palladium example is similar to the polarizing plate of FIG. 2, except that the polarizing plate 200 of the present embodiment further includes a transparent layer 21〇. The transparent layer 21G is disposed on the polymer substrate nG and covers the nanowire 120. The refractive index of the transparent layer 210 affects the extinction ratio of the polarizing plate 2〇〇. Figure 201227003

Rjj is, 8TW 35908twf.d〇c/I

4 is a graph showing the relationship between the refractive index of the transparent layer, the distribution density of the nanowires, and the extinction t of the polarizing plate. The horizontal axis of Fig. 4 is the distribution density of the nanowire (10), that is, the ratio of the surface area of the nanowire 12 〇 to the surface of the polymer substrate 11 。. The vertical axis of Fig. 4 is the refractive index of the transparent layer. In Fig. 4, the extinction ratio of the polarizing plate is indicated by different lines, and the relationship between the depth of the money bar and the extinction ratio of the polarizing plate is shown on the right side of Fig. 4. As can be seen from Fig. 4, the optimized extinction ratio between the refractive index of the bright layer 210 and the distribution density of the nanowire m can improve the extinction ratio of the polarizer. For example, when the simulation is performed with green light having a wavelength of 0.55 μm, if the ratio of the surface area of the nano metal 120 to the surface area of the polymer substrate 11 () is 93%, and the refractive index of the transparent layer 210 is M3, The polarizer is obtained; the ratio of the light to the light is (10) 曰. Figure 5 is a cross-sectional view showing a polarizing plate according to another embodiment of the present invention. Referring to FIG. 5, the polarizing plate 3A of the present embodiment is similar to the polarizing plate of FIG. 2, and the difference is that the surface of the polymer substrate of the polarizing plate of the present embodiment has a substantially parallel-main arrangement direction (class _i The company drains a plurality of micro-grooves 312 to the _). The nanowire 320- of the polarizing plate 3 (8) of the present embodiment is formed in the microgroove 312, so that the nanowire is substantially parallel to the direction of the microgroove 312, that is, the main alignment direction. A simple method for forming the microgrooves 312 on the surface of the polymer substrate 310 is a heterogeneous polymer chip 31 (tetra) surface. In the production of the above-mentioned test pieces, the polymer substrate is first made: two: there is a main direction, and the embodiment is, for example, a polymer base = a wire (four) polymer is difficult. Alternatively, a plurality of county slots are formed on the surface of the polymer substrate to form a parallel parallel main (4). Then, with 201227003 A n

Rj〇yy\j\}^^TV/ 35908twf.doc/I A chemical reaction or physical deposition method forms a nanowire in a substantially parallel main alignment direction on the surface of a polymer substrate. The method of forming the nanowire is, for example, first immersing the treated polymer substrate in a mixed solution of 20 ml of water and 2.2 g of persulfate ((NH4)2S2〇8, ammoniurn persuifate) for 30 seconds. Then, the polymer substrate was taken out from the mixed solution and dried at a temperature of 6 ° C for 10 minutes, and then the dried polymer substrate was placed in 2 ml of water and 0.8 ml of pyrrole (pyrr〇ie). Soak for 3 sec seconds in the mixed solution. Then remove the ruthenium molecular substrate from the mixed solution and dry it at a temperature of 6 ° C for 24 ® hours. Then dry the molecular substrate at an equivalent concentration of 〇1N. Soak in silver acid wall (AgN03) for 30 seconds to complete. As described above, in the polarizing plate of the present invention, the micro-grooves of the polymer substrate itself in the sub-arrangement direction or the surface of the polymer substrate can be used to form the surface of the polymer substrate. The metal lines are substantially parallel to a main alignment direction. Thereby, the polarizing plate has an anisotropy dielectric constant which allows light of a specific linear polarization direction to penetrate, and reflects light whose linear polarization direction is perpendicular to a specific linear polarization direction. Since the polarizing plate of the present invention can be formed by a simple process, the cost can be reduced. Moreover, the polarizing plate of the present invention is easy to increase in size and can be used in an application field. Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims. [Simple diagram] 201227003

35908twf.doc/I Fig. 1 is a schematic view of a polarizing plate according to an embodiment of the present invention. Figure 2 is a cross-sectional view of the polarizing plate of Figure 1. Figure 3 is a cross-sectional view showing a polarizing plate according to another embodiment of the present invention. Fig. 4 is a graph showing the relationship between the refractive index of the transparent layer, the distribution density of the nanowires, and the extinction ratio of the polarizing plate. Figure 5 is a cross-sectional view showing a polarizing plate according to another embodiment of the present invention. [Main component symbol description] • 100, 200, 300: polarizer 110, 310: polymer substrate 120, 320: nanowire D10: main alignment direction 210: transparent layer 312: micro trench

Claims (1)

201227003 FiiyyuU48TW 35908twf.doc/I VII. Patent Application Range: 1. A polarizing plate comprising: a polymer substrate in which the molecules of the polymer substrate have a main alignment direction or the surface of the polymer substrate has a plurality of microchannels substantially parallel to the main array direction; and a plurality of nanowires arranged on the surface of the polymer substrate substantially parallel to the main array direction. 2. The polarizing plate according to claim 1, wherein the polymer substrate is made of polyvinyl alcohol (PVA), polyester (PET) or polyalthene (p〇). Iyimide, pi). 3. The polarizing plate of claim 1, wherein the polymer substrate is stretched during the manufacturing process so that the molecules of the polymer substrate have the main alignment direction. 4. The polarizing plate of claim 1, wherein the surface of the high molecular weight substrate has the micro grooves by friction. 5. The polarizing plate of claim 1, wherein the nanowires are made of silver. 6. The polarizing plate of claim 1, wherein the nanowires comprise from 50% to 100% of the surface area of the polymeric substrate. 7' The polarizing plate of claim i, wherein the nanowires comprise 85% to 95% of the surface area of the polymeric substrate. ^ For example, please refer to the polarizing plate described in item 1 of the patent scope, which is the first! The angle between the non-meter metal wires and the main alignment direction is h, η is the number of the nano metal wires, 11 201227003 i"Djyyuu48TW 35908twf.doc/I ns=Z /=1 3cos2 0-1 2n and S20. 5. 9. The polarizing plate of claim 1, wherein the polarizing plate has a suitable wavelength, and the line width of each of the nanowires is less than or equal to the applicable wavelength. 10. The polarizing plate of claim 1, wherein the polarizing plate has a suitable wavelength, and the length of each of the nanowires is greater than or equal to ten times the applicable wavelength. 11. The polarizing plate of claim 1, further comprising a transparent layer disposed on the polymeric substrate and covering the nanowires. 12