TWI581952B - Method for manufacturing a composite film with high aspect ratio micro-structures - Google Patents

Description

Method for manufacturing composite film with high aspect ratio microstructure

The invention relates to a method for manufacturing a composite film with a high aspect ratio microstructure, which is applied to a peep protection film to provide a good side view anti-peep effect.

Due to the popularity of mobile devices, the need for privacy when using mobile devices in public places has also increased. In the current practice, a form of anti-peep film is generally applied to make any mobile device have an anti-spying effect. In order to achieve good anti-spyness, the anti-spy film is often used to form a plurality of light-shielding microstructures having a certain depth on the film. Please refer to FIG. 1, which is a method for fabricating the privacy film 1 by way of a conventional imprint process, and steps 100 to 103 are indicated by reference numerals in parentheses. In a conventional imprint process, for example, the uncured resin 3 is coated on the transparent substrate 2 (step 100), and the resin 3 is embossed with a microstructured imprint mold 4 (step 101). After the mold release and solidification are formed to form a plurality of groove structures 3a (step 102), the light shielding material 5 is filled in to form the privacy film 1 (step 103). In order to achieve a good anti-snap effect of the side viewing angle, the groove structures 3a need to have a large aspect ratio, but in the imprinting process, in order to facilitate the demolding of the imprinting mold 4 after imprinting, the formed The depth of the groove structures 3a cannot be excessively large to avoid the demolding process, and the groove structures 3a which have not been cured are easily broken. Therefore, the privacy film 1 produced by the conventional imprint process shown in FIG. 1 is often caused by insufficient depth to cause side view prevention. not effectively. If the trench structures 3a are sufficiently deep, the width of the trench structures 3a must be increased accordingly, but this design will also reduce the positive viewing angle of the vertical direction of the privacy film 1 together.

In order to improve the disadvantages of the above-mentioned conventional anti-spy film, the inventors of the present invention have proposed a method for manufacturing a high aspect ratio microstructure composite film for use in a peep prevention film, which does not need to be embossed as in a conventional imprinting mold. It is also necessary to have a demolding step, so that a microstructure having a high aspect ratio can be formed, and the anti-spy film made of the micro-composite composite film has good anti-spyness and transparency.

In view of the above problems of the prior art, the object of the present invention is to provide a method for manufacturing a high aspect ratio microstructure composite film having novelty, advancement and industrial utilization, etc., in order to overcome the difficulties of the existing products.

In order to achieve the above object, the present invention provides a method for fabricating a high aspect ratio microstructure composite film, the method comprising: providing a curved base having a concave surface; and providing a flexible substrate on the concave surface of the curved base, and Coating a curable polymer layer on the surface of the flexible substrate to form a composite film; pre-curing the polymer layer; forming a plurality of groove structures on the polymer layer, and completely curing the polymer layer Removing the composite film from the curved base, and planarizing the composite film to split the groove structures toward the thickness of the polymer layer to form a plurality of high aspect ratio microstructures.

In the method for producing a high aspect ratio microstructure composite film according to an embodiment of the present invention, the flexible substrate has an elongation at break of from 5% to 20%.

In the method for producing a high aspect ratio microstructure composite film according to an embodiment of the present invention, the polymer layer has an elongation at break of from 0 to 2%.

Method for manufacturing high aspect ratio microstructure composite film according to an embodiment of the present invention The aspect ratio of the high aspect ratio microstructure is between 5 and 100.

In a method of fabricating a high aspect ratio microstructured composite film according to an embodiment of the present invention, the manner in which a plurality of groove structures are formed in the polymer layer comprises imprinting using a mold or an engraving wheel.

In a method of fabricating a high aspect ratio microstructured composite film according to an embodiment of the present invention, the manner of curing the polymer layer comprises photocuring or heat curing.

In the method for producing a high aspect ratio microstructure composite film according to an embodiment of the present invention, the flexible substrate is selected from the group consisting of polycarbonate, cellulose acetate, polyolefin, and polyethylene terephthalate.

In a method for producing a high aspect ratio microstructure composite film according to an embodiment of the present invention, the polymer layer is selected from the group consisting of phenolic resin, polymethyl methacrylate, and polystyrene.

In a method for fabricating a high aspect ratio microstructure composite film according to an embodiment of the present invention, the curved base further has an adhesive surface for conforming the flexible substrate to the concave surface of the curved base.

In a method for fabricating a high aspect ratio microstructure composite film according to an embodiment of the present invention, the curved base further includes a plurality of gas passages on the surface of the recess to conduct a vacuum to adsorb the flexible substrate, and conduct a Positive pressure to remove the composite film.

1‧‧‧Provisional film

2‧‧‧Transparent substrate

20‧‧‧ curved base

20a‧‧‧ concave surface

20b‧‧‧ gas passage

21‧‧‧Composite film with high aspect ratio microstructure

21a‧‧‧Composite film

22‧‧‧Flexible substrate

23‧‧‧ polymer layer

23a‧‧‧High aspect ratio microstructure

24‧‧‧Curing device

25‧‧‧ Engraving wheel

26‧‧‧ Groove structure

3‧‧‧Resin

3a‧‧‧ Groove structure

4‧‧‧ Imprinting mold

5‧‧‧ shading materials

A‧‧‧ aspect ratio

L1‧‧‧ inner arc length

L2‧‧‧ outer arc length

D1‧‧‧ thickness

G‧‧‧Width

R‧‧‧ radius of curvature

θ ‧‧‧ center angle

Fig. 1 is a schematic view showing the production of a privacy film for a conventional imprint process.

Fig. 2 is a schematic view showing an embodiment of a method for manufacturing a high aspect ratio microstructure composite film according to an embodiment of the present invention.

3a to 3b are diagrams for calculating the aspect ratio of the formed microstructure in the method for fabricating a composite film having a high aspect ratio microstructure.

Fig. 4 is a schematic view showing a curved base used in a method for manufacturing a high aspect ratio microstructure composite film according to another embodiment of the present invention.

In order to make the features, the contents and advantages of the invention and the effects thereof can be more easily understood, the present invention will be described in detail with reference to the accompanying drawings, The use of the present invention is not intended to be a true proportion and precise configuration after the implementation of the present invention. Therefore, the scope and configuration relationship of the attached drawings should not be interpreted or limited. Explain first.

The embodiments of the method for fabricating the high aspect ratio microstructured composite film according to the present invention will be described below with reference to the related drawings. For ease of understanding, the same elements in the following embodiments are denoted by the same reference numerals.

Referring to FIG. 2, in a preferred embodiment, the present invention provides a method of fabricating a composite film 21 having a high aspect ratio microstructure. Steps 200 through 205 are indicated by reference numerals in parentheses, the steps comprising: providing an arcuate base 20 having a recessed surface 20a (step 200); providing a flexible substrate 22 to the recessed surface 20a of the curved base 20 And coating a curable polymer layer 23 on the surface of the flexible substrate 22 to form a composite film 21a (step 201); pre-curing the polymer layer 23 (step 202), for example, depending on the polymer 23 a type, using a curing device 24 that emits light energy or heat, pre-curing the polymer layer 23; forming a plurality of groove structures 26 on the polymer layer 23 using an engraving wheel 25 or an imprint template having a microstructure on the surface ( Step 203); and completely curing the polymer layer 23 with the curing device 24 (step 204); removing the composite film 21a from the curved base 20, and planarizing the composite film 21a (step 205) to make the The groove structure 26 splits toward the thickness direction of the polymer layer 23 to form a plurality of high and deep widths The composite film 21 having a high aspect ratio microstructure is obtained than the microstructure 23a.

Please refer to FIGS. 3a and 3b, which are calculation methods for controlling the aspect ratio of the formed high aspect ratio microstructure 23a in the method for fabricating a composite film having a high aspect ratio microstructure. The aspect ratio A of the high aspect ratio microstructure 23a satisfies Equation 1: A = d1/G, where d1 is the thickness of the polymer layer 23 and G is the width of the formed high aspect ratio microstructure 23a. When the total number of the recess structures 26 is N, the total number of the high aspect ratio microstructures 23a formed is also N, so the widths of the high aspect ratio microstructures 23a are N x G. And the sum is the difference between the outer arc length L2 and the inner arc length L1 before the flattening of the polymer layer 23, so the width G of each high aspect ratio microstructure 23a satisfies the formula 2: G=(L2-L1) /N=((2π(R+d1)-2πR)× θ /360°)/N=(2πd1× θ /360°)/N, where R is the radius of curvature of the polymer layer 23 imparted by the curved base , θ is the central angle corresponding to the arc length of the polymer layer 23. Then, the second formula is substituted into the first formula, and the formula 3 is obtained: A=(360°/ θ )×(N/2π). Therefore, the aspect ratio A of the high aspect ratio microstructures 23a can be estimated by controlling the central angle θ of the curved base 20 and the total number N of high aspect ratio microstructures 23a to be formed.

In the manufacturing method of the high aspect ratio microstructure composite film according to an embodiment of the present invention, the flexible substrate 22 has an elongation at break of 5% to 20%. For example, the flexible substrate 22 includes However, it is not limited to polycarbonate, cellulose acetate, polyolefin or polyethylene terephthalate, etc., to provide certain flexibility and toughness without being easily broken. The polymer layer 23 has a breaking elongation of 0 to 2%, and is a hard and brittle material, and includes, for example, a phenol resin, polymethyl methacrylate or polystyrene. Therefore, when the polymer layer 23 is planarized, the groove structures 26 provide a stress gap so that the thickness direction of the polymer layer 23 can be split to form a plurality of high aspect ratio microstructures 23a, and When the groove structures 26 are formed, since the functions of the groove structures 26 are only used to provide stress gaps, the aspect ratio thereof may be, for example, only 0.5 to 5, so that the problem of poor mold release after imprinting is less likely to occur.

In the method for fabricating a high aspect ratio microstructure composite film according to an embodiment of the present invention, the aspect ratio of the high aspect ratio microstructure 23a is between 5 and 100.

In a method of fabricating a high aspect ratio microstructured composite film in accordance with an embodiment of the present invention, the manner in which the plurality of groove structures 26 are formed in the polymer layer 23 comprises embossing using a mold or engraving wheel having a microstructure on the surface.

In the method of fabricating the high aspect ratio microstructured composite film of one embodiment of the present invention, the manner of curing the polymer layer 23 comprises photocuring or heat curing.

In the manufacturing method of the high aspect ratio microstructure composite film according to an embodiment of the present invention, the concave surface 20a of the curved base 20 is an adhesive surface, and the flexible substrate 22 is applied to the curved shape. The recessed surface 20a of the base 20.

In the manufacturing method of the high aspect ratio microstructure composite film according to another embodiment of the present invention, as shown in FIG. 4, the curved base 20 further includes a plurality of gas passages 20b on the concave surface 20a to conduct a negative pressure. The flexible substrate 22 is adsorbed and a positive pressure is conducted to remove the composite film 21a.

The embodiments described above are merely illustrative of the technical spirit and the features of the present invention, and the objects of the present invention can be understood by those skilled in the art, and the scope of the present invention cannot be limited thereto. That is, the equivalent variations or modifications made by the spirit of the present invention should still be included in the scope of the present invention.

20‧‧‧ curved base

20a‧‧‧ concave surface

21‧‧‧Composite film with high aspect ratio microstructure

21a‧‧‧Composite film

22‧‧‧Flexible substrate

23‧‧‧ polymer layer

23a‧‧‧High aspect ratio microstructure

24‧‧‧Curing device

25‧‧‧ Engraving wheel

26‧‧‧ Groove structure

Claims (10)

A method for manufacturing a composite film having a high aspect ratio microstructure, comprising the steps of: providing a curved base having a concave surface; providing a flexible substrate on the surface of the concave portion of the curved base and coating a curable layer a polymer layer on the surface of the flexible substrate to form a composite film; pre-curing the polymer layer; forming a plurality of groove structures on the polymer layer, and completely curing the polymer layer; The base removes the composite film; and planarizing the composite film to split the groove structures toward the thickness of the polymer layer to form a plurality of high aspect ratio microstructures. The method for producing a high aspect ratio microstructure composite film according to claim 1, wherein the flexible substrate has an elongation at break of from 5% to 20%. The method for producing a high aspect ratio microstructure composite film according to claim 1, wherein the polymer layer has an elongation at break of from 0 to 2%. The method for manufacturing a high aspect ratio microstructure composite film according to claim 1, wherein the high aspect ratio microstructure has an aspect ratio of 5 to 100. The method for manufacturing a high aspect ratio microstructure composite film according to claim 1, wherein the manner of forming the plurality of groove structures in the polymer layer comprises using a mold or an engraving wheel to imprint. The method for producing a high aspect ratio microstructure composite film according to claim 1, wherein the method of curing the polymer layer comprises photocuring or heat curing. The method for producing a high aspect ratio microstructure composite film according to claim 1, wherein the flexible substrate is selected from the group consisting of polycarbonate, cellulose acetate, polyolefin, and polyethylene terephthalate. The method for producing a high aspect ratio microstructure composite film according to claim 1, wherein the polymer layer is selected from the group consisting of phenolic resin, polymethyl methacrylate, and polystyrene. The method for manufacturing a high aspect ratio microstructure composite film according to claim 1, wherein the surface of the concave portion of the curved base is an adhesive surface, and the flexible substrate is applied to the curved base. The surface of the recess. The method for manufacturing a high aspect ratio microstructure composite film according to claim 1, wherein the curved base further comprises a plurality of gas passages on the surface of the recess to conduct a vacuum to adsorb the flexible substrate, and A positive pressure is conducted to remove the composite membrane.