TWI408041B - A manufacturing method for mold to produce brightness enhancement films - Google Patents

Abstract

A manufacturing method for mold to produce brightness enhancement films comprises the steps of: forming a microlens array on a first plate to make a first mold that has spacing; imprinting the microlens array of the first mold on a Bulk metallic glass that is heated to Tg thereof by several times of hot embossing and cooling the imprinted Bulk metallic glass below Tg thereof to make a second mold, which has spacing smaller than that of the first mold.

Description

Method for manufacturing mold for producing brightness enhancement film

The present invention relates to a method of manufacturing a mold, and more particularly to a method for producing a mold for producing a brightness enhancement film by reducing the size of the surface structure of the mold by a hot press transfer technique.

The LCD of the Liquid Crystal Display Panel (LCD Panel) does not emit light itself. The panel light source is supplied by a backlight module in the liquid crystal display, and the backlight module is provided with an optical film and The brightness enhancement film causes the light source with sufficient brightness, uniform distribution and high brightness to be converted into a high brightness and uniform surface light source through the effective light mechanism.

At present, the brightness enhancement film of the conventional optical film can be formed by injection molding. First, the required molding die must be prepared by using a Lithographic GalVanoformung Abformung (LIGA) process to form a crucible structure on a substrate, and then electroforming to remove the desired crucible structure mold. The 稜鏡 structure mold is placed on the injection molding machine, and then the molten polymer material is injected and solidified before being subjected to a trimming operation to prepare a desired brightness enhancement film.

However, the above-described photolithographic molding of the mold has a size limitation, which makes it impossible to produce a very small crucible microstructure. On the other hand, when the brightness-increasing film is produced by injection molding, it is necessary to prepare a desired mold and heat-melt the polymer material at a high temperature in advance to perform the subsequent molding operation, which not only causes the complicated process of the conventional brightness enhancement film to be complicated, but also heats and melts. The polymer material is also Increasing the energy and time spent on the process, coupled with the machine used for injection molding, is required to be in an extremely high temperature and high pressure working environment, resulting in expensive equipment itself, which in turn leads to a relatively high production cost of the brightness enhancement film. In addition, after waiting for the polymer material to be cooled and solidified in the mold, the next brightness-increasing film can be produced, which makes it impossible to continuously produce the brightness-increasing film and reduces the manufacturing efficiency; moreover, the brightness can be formed only under a single mold. The film makes the brightness-increasing film still different from the microstructure of the mold, which reduces the precision of the process.

Further, the mold for injection molding described above may be prepared in advance by using a milling technique. However, in general, the conventional milling technology uses a tool to mill the shape required for the mold, but is limited by the size of the tool, so that the surface structure of the mold (especially the groove structure) can be the smallest and the same size. The nose radius of the tool has led to the current technological industry in which the size is miniaturized, and the processing method of the mold has been unable to meet the current industrial needs. For the above reasons, there is a need to further improve the above-described manufacturing method for a mold for producing a brightness enhancement film.

In order to improve the manufacturing method of the above-mentioned conventional mold for manufacturing a brightness enhancement film, there are disadvantages such as size limitation of the surface structure of the mold, and the present invention provides a method for manufacturing a mold for manufacturing a brightness enhancement film, the main object of which is Effectively and accurately reduce the surface structure size of the mold used to make the brightness enhancing film for subsequent formation of the brightness enhancing film.

In order to achieve the foregoing object, the technical means utilized by the present invention and the achievable effects by the technical means include: A manufacturing method of a mold for manufacturing a brightness enhancement film, comprising the steps of: forming a microlens array structure on a first substrate to prepare a first mold, wherein the first mold has a microlens pitch; heating a metal glass substrate to a glass transition temperature thereof, and transferring the microlens array structure on the first mold to one surface of the metal glass substrate by several hot pressing, and then cooling the metal glass substrate Below the glass transition temperature, as a second mold, and the microlens pitch of the second mold is smaller than the microlens pitch of the first mold. Thereby, a small surface structure size can be obtained accurately on the surface of the second mold, and by using the second mold as the forming mold of the brightness enhancement film, not only the manufacturing cost thereof can be reduced, but also the continuous production can be achieved. Bright film to enhance the efficiency of production.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

Referring to FIGS. 1 and 2, a first step S1 of a method for manufacturing a mold for manufacturing a brightness enhancement film according to a preferred embodiment of the present invention is: processing a trigonal pyramidal micro on a first substrate. The lens array structure is used to prepare a first mold 1. More specifically, because the machine equipment required for machining technology and its maintenance cost are low, and the manufacturing process is simple, the first step S1 utilizes machining technology (for example, precision diamond grinding technology). Forming the trihedral pyramidal microlens array structure on a surface of one of the first substrates, and having a microlens pitch "a" and a pyramid height "H", the microlens pitch "a" being adjacent The pitch of the tips of the two trihedral pyramids 180 microns [μm], the pyramid height "H" is the distance from the lowest point between two adjacent trihedral pyramids to the tip of the trihedral pyramid, wherein the first substrate is preferably selected from the group consisting of steel material. Thereby, as shown in FIG. 2, the processed first substrate is used as the first mold 1, and the first mold 1 has a three-sided pyramidal microlens array structure for performing a subsequent work step.

Referring to FIGS. 1 to 6, a second step S2 of the manufacturing method of the mold for manufacturing a brightness enhancement film according to a preferred embodiment of the present invention is a three-sided pyramidal microlens array structure on the first mold 1. The embossing is performed on a metal glass substrate 2 to prepare a second mold 2', and the microlens pitch of the second mold 2' is smaller than the microlens pitch of the first mold 1. More specifically, the material of Bulk metallic glasses (BMGs) is a non-crystalline semi-molten state at a glass transition temperature point [Tg] or higher, and thus has a low viscosity, high flow rate thermoplastic property, and is easy to be used. The desired pattern is transferred onto the metallic glass material; in addition, if the metallic glass material is cooled to the supercooled region [Tx], it can be rapidly solidified and has a certain hardness. Preferably, the present invention selects an alloy having a glass transition temperature between 370K and 450K at an absolute temperature as the metallic glass substrate 2 of the present invention for performing a hot stamping operation, and therefore, it is preferably selected from the group consisting of gold. An alloy of elements such as bismuth or bismuth. In the second step S2, as shown in FIG. 2, the first mold 1 and the metal glass substrate 2 are thermally connected and fixed to a hot stamping machine 3 and a lower heating platform 31, 32, respectively. The temperature of the metal glass substrate 2 is controlled by the lower heating platform 32 to be between 370K and 450K, the upper heating platform 31 is moved toward the lower heating platform 32, and the pressure is superposed on the lower heating platform 32. So that the first mold 1 has a triangular pyramid shape The surface of the microlens array structure is superposed on the metal glass substrate 2, and the triangular pyramid tip portion of the three-sided pyramidal microlens array structure of the first mold 1 is transferred onto one surface of the metallic glass substrate 2 [ As shown in FIG. 3, further, as shown in FIGS. 4 and 5, the upper heating stage 31 is reset and then moved laterally, and the above-mentioned imprinting operation is repeated to facilitate pressing on the surface of the metallic glass substrate 2. Printing a three-sided pyramidal microlens array structure having a microlens pitch "b" and a pyramid height "h", and the microlens pitch "b" is between about 2 and 50 μm, and the pyramid height "h" is smaller than the The pyramid height "H" of the first mold 1 is. When the three-sided pyramidal microlens array structure is spread over the entire surface of the metallic glass substrate 2, the second mold 2' is formed (as shown in Figs. 5 and 6). Compared with the microlens pitch "a" of the first mold 1, the second mold 2' has a smaller microlens pitch "b" to make the brightness required for forming by the second mold 2'. membrane.

Referring to Figures 7 and 8, when the brightness enhancing film is produced by using the second mold 2' of the present invention, the second mold 2' and the polymer substrate 4 are thermally connected and fixed to the heat, respectively. The upper and lower heating platforms 31, 32 of the embossing machine 3; the temperature of the polymer substrate 4 is controlled by the lower heating platform 32 to be between 370K and 470K, preferably between 390K and 410K, The polymer substrate 4 is placed in a semi-molten state; then, the surface of the second mold 2' having a triangular pyramidal microlens array structure is pressure-bonded to one surface of the polymer substrate 4 to make the second The three-sided pyramidal microlens array microstructure of the mold 2' is transferred and formed on the surface of the polymer substrate 4 by a hot stamping technique, thereby forming a brightness enhancement film 5 (as shown in FIG. 8). . Furthermore, when the surface of the polymer substrate 4 is hot-embossed is larger than the second mold When the surface of the three-sided pyramidal microlens array structure is formed by 2', the second mold 2' is moved by the upper heating platform 31 to imprint the unprocessed surface of the polymer substrate 4. . The polymer substrate 4 is preferably selected from the group consisting of polymethyl methacrylate (PMMA), UV curable resin or polyethylene terephthalate (PET). And other polymer materials.

In addition to forming the brightness enhancement film 5 by hot stamping technology, it is also possible to uniformly coat the surface of the second mold 2' having a triangular pyramidal microlens array structure by spin coating. The ultraviolet curing resin, wherein the ultraviolet curing resin is preferably selected from the group consisting of UV glue; after the spin coating operation is completed, the ultraviolet curing resin is irradiated with ultraviolet light for a predetermined time to cure the ultraviolet curing resin; finally, The cured UV curable resin is peeled off from the second mold 2' to obtain a brightness enhancement film.

As described above, the present invention utilizes the physicochemical properties of the metallic glass substrate 2 to perform hot stamping on the metallic glass substrate 2 by using the first mold 1 prepared in advance to efficiently and accurately prepare the microlens. The second mold 2' of the trihedral pyramidal microlens array structure having a pitch as small as 2 to 50 [mu]m is used for subsequent rapid and continuous fabrication of the brightness enhancing film.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

1‧‧‧First mould

2‧‧‧Metal glass substrate

2'‧‧‧ second mould

3‧‧‧Hot press

31‧‧‧Up heating platform

32‧‧‧Under heating platform

4‧‧‧ polymer substrate

5‧‧‧Brightening film

S1‧‧‧ first step

S2‧‧‧ second step

Figure 1 is a flow chart showing a method of manufacturing a mold for producing a brightness enhancing film in accordance with a preferred embodiment of the present invention.

2 is a schematic view showing a manufacturing method of a mold for manufacturing a brightness enhancement film according to a preferred embodiment of the present invention. A first mold and a metal glass substrate are disposed on a hot stamping machine.

Fig. 3 is a schematic view showing the first mold of the method for producing a mold for producing a brightness enhancement film according to a preferred embodiment of the present invention, which is imprinted on the metal glass substrate.

Figure 4 is a schematic view showing the first mold of the method for manufacturing a mold for producing a brightness enhancement film according to a preferred embodiment of the present invention, which is laterally moved and then imprinted on the metal glass substrate.

Fig. 5 is a view showing the completion of the second mold of the method for producing a mold for producing a brightness enhancement film according to a preferred embodiment of the present invention.

Figure 6 is a plan view of a second mold for a method of manufacturing a mold for producing a brightness enhancing film in accordance with a preferred embodiment of the present invention.

Figure 7 is a schematic view showing the second mold of the manufacturing method of the mold for producing a brightness enhancement film according to a preferred embodiment of the present invention, which is imprinted on a polymer substrate.

Figure 8 is a cross-sectional view showing a brightness enhancing film of a method for producing a mold for producing a brightness enhancing film according to a preferred embodiment of the present invention.

S1‧‧‧ first step

S2‧‧‧ second step

Claims (9)

A manufacturing method of a mold for manufacturing a brightness enhancement film, comprising: forming a microlens array structure on a first substrate to prepare a first mold, and the first mold has a microlens pitch; Heating a metal glass substrate to above its glass transition temperature, and transferring the microlens array structure on the first mold to one surface of the metal glass substrate via several hot pressing, and then cooling the metal glass substrate The material is below the glass transition temperature to serve as a second mold, and the microlens pitch of the second mold is smaller than the microlens pitch of the first mold. The method for manufacturing a mold for producing a brightness enhancement film according to the above-mentioned patent application, wherein the glass transition temperature of the metal glass substrate is between 370K and 450K. The method for producing a mold for producing a brightness enhancement film according to the second aspect of the invention, wherein the metal glass substrate is selected from the group consisting of alloy materials containing one of gold, bismuth and antimony. The manufacturing method of the mold for manufacturing a brightness enhancement film according to the first or second aspect of the patent application, wherein the microlens array structure of the first mold is a triangular pyramid shape, and the first mold is heated and rotated. When printed on the surface of the metallic glass substrate, the trigonal pyramidal microlens array structure is partially transferred onto the surface of the metallic glass substrate only by the tip of each of the three-sided pyramidal structures of the first mold. The height of the pyramid of the two molds is smaller than the height of the pyramid of the first mold. A manufacturing method for a mold for manufacturing a brightness enhancing film according to the above-mentioned claim 1, wherein the microlens pitch is adjacent to two trihedral angles The pitch of the tip of the cone, the microlens pitch of the first mold is 180 microns, and the microlens pitch of the second mold is between 2 and 50 microns. The method for manufacturing a mold for producing a brightness enhancement film according to the fourth aspect of the invention, wherein the microlens pitch is a pitch of tips of two adjacent three-sided pyramids, and the microlens pitch of the first mold is 180 microns, and the microlens spacing of the second mold is between 2 and 50 microns. The method for manufacturing a mold for producing a brightness enhancement film according to the first aspect of the invention, wherein the first substrate is a metal material of a steel type, and the first substrate is processed by a precision diamond grinding process. Processing forms the first mold. The method for manufacturing a mold for producing a brightness enhancement film according to the first aspect of the invention, wherein the surface of the second mold having the microlens array structure is thermally embossed when the brightness enhancement film is produced by using the second mold. The polymer substrate is formed to form a brightness enhancement film. The manufacturing method of a mold for manufacturing a brightness enhancement film according to the first aspect of the invention, wherein the brightness enhancement film is produced by using the second mold, and is utilized on a surface of the second mold having a microlens array structure. A UV curable resin is spin coated to form a brightness enhancing film.