KR20170138241A - Method for removing protection film of polarizing film laser cutting and polishing apparatus for implementing the same - Google Patents

Abstract

Disclosed is a method for removing a protection film from laser-cut polarizing films, which can improve exfoliation properties in the protection film by preventing an increase in initial exfoliation force generated when removing the protection film from the laser-cut polarizing film. Moreover, disclosed is a polishing device for conducting the same. To this end, the method for removing the protection film from the laser-cut polarizing film comprises the following steps: cutting the polarizing films by emitting laser beams; polishing a recast layer and a shoulder on the polarizing film formed by the laser irradiation so as to remove the same; and removing the protection film from the polished polarizing film.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for removing a protective film of a laser cut polarizing film, and a polishing apparatus for implementing the same.

The present invention relates to a method for removing a protective film of a laser cut polarizing film and a polishing apparatus for implementing the same, and more particularly, to a method for removing a protective film from a laser cut polarizing film, To a protective film removing method of a laser cut polarizing film which improves the peelability of a protective film and a polishing apparatus for implementing the protective film.

When irradiating a multilayer film (polarizing film) while moving a focused laser beam, the film can be effectively cut so that micro cracks do not occur along the cut surface. Such laser cutting is performed by a light absorption-deterioration-melting and vaporization reaction occurring between the film and the laser beam, and a protective film for protecting the surface of the film after the laser cutting process is removed The finished product is produced. A conventional polarizing plate protective film removing apparatus used for removing such a protective film is a device for removing a protective film from a protective film by attaching a tape to a longitudinal direction or an edge on a top surface of a protective film attached to upper and lower surfaces of a polarizing plate by using a plurality of rollers, The end portion is caught and moved in the upward direction or the film center direction, thereby peeling the protective film.

Korean Patent Publication No. 10-2015-0075616

As described above, the cutting (cutting) of the multilayer film (polarizing film) is performed by a laser, and after the cutting, the final product can be manufactured only through a process of removing the protective film. However, when the multilayered film is cut by using a laser, the upper surface cutting portion of the film is bumpy or shoulder due to deterioration, so that steps of several tens of micrometers (탆) in height are generated, The resin is melted by heat and a recast layer, which is solidified again, is formed along the inclined portion of the cutting face. In addition, when the protective film of the laser cut multi-layer film is removed, the initial peeling force is increased due to the above-described problems, and the removal of the protective film is not easy. As described above, if the process of removing the protective film is not easy, problems such as a decrease in productivity, an occurrence of foreign matter due to an ineffective temporary response, and an increase in a defect rate arise.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a protective film of a laser cut polarizing film which can improve the peeling property of a protective film by suppressing an initial peeling force increase phenomenon that occurs when a protective film is removed from a laser cut polarizing film And a polishing apparatus for implementing the same.

According to an aspect of the present invention, there is provided a polarizing plate comprising: a polarizing film; Grinding and removing a shoulder and a recast layer on a polarizing film formed by irradiation of the laser; And removing the protective film from the polished polarizing film. The present invention also provides a method of removing a protective film of a laser cut polarizing film.

Further, the present invention provides a polishing apparatus for implementing a protective film removing method of the laser cut polarizing film.

The method of removing the protective film of the laser cut polarizing film according to the present invention and the polishing apparatus for implementing the same can suppress the increase of the initial peeling force generated when the protective film is removed from the laser cut polarizing film, It is possible to improve the property.

1 is a side sectional view of a polarizing film used in the present invention.
2 is a side cross-sectional view of a laser cut polarizing film.
3 is a view showing a state (A) of removing a protective film from a laser-cut polarizing film with a tape and a state (B) of removing a protective film with a tape from a film cut mechanically.
FIGS. 4 and 5 are views showing a state where a polishing apparatus according to the present invention is applied to a polarized light-cut polarized film.
FIGS. 6 and 7 are graphs comparing initial peeling forces of protective films according to various processes. FIG.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

A method of removing a protective film of a laser cut polarizing film according to the present invention includes a step of cutting a polarizing film by irradiating with a laser, a shoulder and a recast layer on a polarizing film formed by irradiation of the laser, Removing the protective film from the polished polarizing film, and removing the protective film from the polished polarizing film.

The step of irradiating the polarizing film with a laser beam includes irradiating a multilayer polarizing film while moving a focused laser beam to effectively cut the film in a direction in which the films positioned on each layer in the film are laminated (Or cut) the laser beam, the laser beam is cut by the light absorption-deterioration-melting and vaporization reaction occurring between the film and the laser beam. When the laser beam is cut in the polarizing film, (micro crack) phenomenon does not occur.

In addition, unlike the conventional mechanical cutting method for cutting a film including a plastic material, if a film is cut by using the laser as described above, not only a supporting member and other parts of the cutting tool are required, It is possible to cut without damaging the workpiece due to physical distortion of the workpiece due to processing. In addition, it is possible to easily obtain various types of workpieces through a magnetic mirror array or an automatic programming of the stage, by locating the trajectory of the laser beam, and to cope with the change of the shape of the workpiece quickly by means of a simple CAD There are many advantages. It is important to minimize the quality deterioration of the cut surface due to deterioration of the cut surface in the laser cutter having such advantages.

On the other hand, a laser to be used for cutting of the polarizing film, the carbon dioxide (CO ₂₎ laser, a helium-neon (He-Ne) laser, argon (Ar) laser, an excimer (excimer) laser, a fiber laser, a Nd: YAG ( neodymium-doped yttrium aluminum garnet) lasers and semiconductor lasers. In addition, a conventional laser used for cutting a polarizing film can be used without any particular limitation.

FIG. 1 is a side sectional view of a polarizing film used in the present invention. As shown in FIG. 1, the polarizing film has a layer composed of a TAC (triacetate cellulose) film or a COP (cycloolefin polymer) A polyvinyl alcohol (PVA) film layer is disposed therebetween, and a protective film layer made of a surface treatment layer and PET is formed on one side of the TAC film or the COP film and a release film made of PET Respectively. However, the polarizing film shown in Fig. 1 is merely an example of the polarizing film used in the present invention. The polarizing film used in the present invention can use various kinds of commonly used polarizing films without any particular limitation , The thickness of the film constituting each layer of the polarizing film may also be set to a thickness as shown in Fig. 1, but the present invention is not limited thereto.

Next, a step of polishing a recast layer formed along a shoulder and a taper on a polarizing film generated by irradiation of the laser will be described. Fig. 2 is a side sectional view of a laser cut polarizing film. When the polarizing film is cut by irradiation with a laser, the polarizing film is shaped as shown in Fig. That is, when the polarizing film is irradiated with a laser beam, the laser light is irradiated onto the polarizing film due to the deterioration by the laser, and in the heat affected portion of the protective film layer and the release film layer (see FIG. 1) located on both outer sides of the polarizing film, (Or bumps 2, 4) are formed, resulting in step differences of several tens of micrometers (占 퐉). This is because instantaneous volume expansion occurs due to the local light heat reaction of the laser incident on the protective film (see Fig. 1) located at the outer periphery of the polarizing film, and the polymer chain returns to its original position and the volume expansion is minimized This is caused by cooling without time margin. These shoulders 2 and 4 have a step difference in the edge of the cutting edge in the process of stacking after the polarizing film is cut and the step between the central part and the edge part of the product is increased to cause a problem of warping or distortion of the product , There is a problem that when the protective film is removed from the polarizing film (peeling using the tape), the adhesion area of the tape adhered to the end of the protective film is reduced, and the peeling action is hindered.

When a laser beam is irradiated onto the polarizing film, a taper 6 having a constant inclination is formed by cutting the cut surface vertically. Particularly, in the plastic film having low thermal conductivity, the heat affected zone of the incidence- And as a result, the cutting surface has a certain slope.

(Not shown) is formed on the outer surface 6a of the taper 6 formed as described above. Since the thermal conductivity of the polymer film is low, the heat applied during the laser irradiation can be applied to the periphery They are not transferred and stay in the laser irradiation area. When the laser is superimposed, additional heat accumulates at the same position. In addition, since the laser beam has a fixed spot size, the planar energy distribution of the beam spot has a Gaussian shape, so that the spot periphery of the beam is also exposed to the beam energy, . When the excessive heat is accumulated in the laser irradiation area, the polymer resin located on the cut face side of the film is melted by heat, and then the reac- tive layer in which the polymer resin is solidified again by quenching to room temperature, (6a). The thus-formed re-adherent layer is formed on the interlayer boundary of the polarizing film and capping the end of the protective film, which has a problem of detaching the protective film from the polarizing film.

When the polarizing film is cut by irradiating with a laser beam, the protective film (see FIG. 1) located on the outer periphery of the polarizing film must be removed from the polarizing film so as to protect the surface of the polarizing film from contamination. Due to the increase in the initial peel force (the force required to initially peel the protective film from the inner layer of the polarizing film located below and below the protective film) by the protective layer (2,4) and the reattach layer (not shown) The removal of the film is not easy. The initial peeling force increase phenomenon hinders the efficiency of the production process. In the present invention, the initial peeling force is lowered to easily remove the protective film from the polarizing film.

3 is a view showing a state (A) of removing a protective film from a laser-cut polarizing film with a tape and a state (B) of removing a protective film with a tape from a film cut mechanically. As shown in FIG. 3B, in the case of a film cut by a mechanical method (CNC (Computer Numerical Control)), since the shoulder and the re-adhering layer are not formed on the polarizing film, the protective film 20 is removed A tape 22 for removing the protective film 10 is provided in the case of a laser cut film as shown in Fig. 3 (A) The protective film 10 is not adhered sufficiently by the shoulder 2 and the re-adhering layer 8, so that the protective film 10 is difficult to peel off.

Therefore, in the present invention, by introducing a low-cost simple polishing apparatus (or a polishing apparatus), it is possible to effectively prevent the causes of the peeling force increase, that is, the shoulders 2, 4 and the recoat layer 8 formed on the polarizing film The purpose is to remove,

Specifically, the upper surface of the polarizing film is polished to remove the recoat layer formed on the outer surface of the shoulder and shoulder, or the side surface of the polarizing film is polished to remove the recoat layer formed along the taper, The peeling force was adjusted to a level similar to the initial peeling force of the film. On the other hand, in the case of polishing the upper portion of the film, if the number of times of reciprocation of the polishing apparatus is increased, there is a possibility that the polarizing plate positioned under the protective film may be damaged, so that the micro- It is preferable to reciprocate the apparatus. The polishing apparatus will be described later.

After the shoulders 2, 4 and the re-adherence layer 8 of the laser cut polarizing film are polished, the protective film is removed from the polished polarizing film to complete the product. That is, according to the present invention, when the shoulders 2, 4 and the re-adhering layer 8 formed on the laser-cut polarizing film are polished, although the polarizing film is cut using the laser, It is possible to easily detach and remove the protective film from the polarizing film with a small force after maximizing the adhesion area between the tape and the protective film, similarly to the case of cutting the polarizing film mechanically. Namely, in other words, when the shoulders 2 and 4 and the re-adhering layer 8 of the polarizing film are polished, the adhesion area of a sticky material such as a tape adhered to the protective film is increased, The capping effect of the re-adhering layer 8 is canceled and the initial peeling force of the protective film is reduced.

The protective film serves to protect the surface of the polarizing film from contamination. As a method for removing the protective film, a tape itself containing a viscous adhesive component (not depending on a separate tool) However, it is most preferable to use a roller in which a point-adhesive tape is wound around the surface, a roller in which the point-adhesive tape runs continuously on the outer circumferential surface, or a roller in which a point- The substrate can be used without any particular limitation if it is a substrate containing a viscous component so that the protective film can be easily removed from the polarizing film.

Next, a polishing apparatus for implementing a protective film removing method of a laser cut polarizing film according to the present invention will be described. As described above, the polishing apparatus is used to remove the shoulder (2,4) and the re-adhering layer (8) formed on the polarized film that has been cut off from the laser. Simply, sand paper In addition, it is also possible to use a polishing roller in which a belt surrounds one or more outer peripheral surfaces of a roller or a polishing wheel used to polish a semiconductor substrate or the like. In addition, Can be used without any particular limitation, provided that it has a material capable of removing the formed shoulder (2, 4) and the recoat layer (8). The material of the belt and the polishing wheel of the polishing roller should be capable of removing the shoulder (2,4) and the re-adhering layer (8) formed on the polarizing film. The polishing roller and the polishing wheel are commonly The abrasive such as alumina, silicon carbide, and gold stones (emery) is basically adhered to the abrasive cloth by glue.

4 and 5 are views showing a state in which the polishing apparatus according to the present invention is applied to a polarized light-cut polarized film, wherein FIG. 4A shows a state in which the upper surface (more precisely, a shoulder) FIG. 4B is a perspective view of the upper surface of the polarizing film, FIG. 4B is a perspective view of the upper surface of the polarizing film, FIG. 4C is a side view of the polarizing film (more precisely, FIG. 5A is a side view of polishing the upper surface of the polarizing film using the polishing wheel, and FIG. 5B is a side view of polishing the upper surface of the polarizing film using the polishing wheel. And FIG. 5C is a side view of polishing the side surface of the polarizing film using the polishing wheel, respectively. Further, in Figs. 4 and 5, the arrow indicates the traveling direction of the polishing apparatus, but the curved arrow on the polishing wheel shown in Fig. 5B means that the wheel rotates for polishing. On the other hand, the side grinding may be applied to one polarizing film for the purpose of eliminating the capping effect due to the formation of the recoat layer between the protective film and the polarizing film inner layer, As shown in the figure, it is preferable that, when using any polishing apparatus, the side of the polarizing film is polished, the work is performed simultaneously after the plurality of polarizing films are stacked for shortening the time or for stable reciprocating motion of the polishing apparatus .

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as set forth in the appended claims. Such changes and modifications are intended to be within the scope of the appended claims.

[Example 1] Measurement of initial peeling force of protective film after polishing the upper surface of laser-cut polarizing film

After cutting the polarizing film by irradiating a laser beam, a polarizing film having a shoulder and a part of a re-adherent layer formed using a sandpaper (# 2000) so that a shoulder formed at a level of several tens of micrometers (m) The top was polished. Subsequently, in order to remove the protective film located at the top of the polarizing film, the protective film was removed by pulling the tape in the opposite direction (180 DEG) of the extension line after attaching the tape to the protective film, The initial peeling force was measured five times at room temperature (peel test), and the peel strength was measured three times except for the maximum value and the minimum value of the measurement results The results are shown in Table 1 below.

On the other hand, when the number of times of reciprocation of the sandpaper increases during the polishing, there is a possibility that the polarizing plate positioned under the protective film may be damaged, so that the micro-wear is left on the upper cut line of the protective film, Lt; / RTI > The peeling force was measured using a TA-XT2 plus (Stable Micro Systems, UK) (mode: Tension, Trigger force: 5 gf) as the peel strength measurement device, / min, the angle of peeling was 180 ° (°), and the size of the specimen was 15 cm × 2.54 cm.

[Example 2] Measurement of initial peeling force of protective film after side-polishing of laser-cut polarizing film

After the polarizing film was cut by irradiating the laser beam, the side surface of the polarizing film having the recoat layer formed thereon was polished by using a sandpaper (# 2000) so that the re-adhering layer formed at a level of several tens of micrometers (탆) was removed. Subsequently, in order to remove the protective film located at the top of the polarizing film, the protective film was removed by pulling the tape in the opposite direction (180 DEG) of the extension line after attaching the tape to the protective film, The initial peeling force was measured five times at room temperature (peel test), and the peel strength was measured three times except for the maximum value and the minimum value of the measurement results The results are shown in Table 1 below.

On the other hand, when the number of reciprocation of the sandpaper increases during the polishing, the side surface of the polarizing plate positioned under the protective film may be damaged, and the sandpaper may be damaged only within five times I made a round trip. The peeling force was measured using a TA-XT2 plus (mode: Tension, Trigger force: 5 gf) as the peeling force measurement device, the peeling speed was 300 mm / min, the peeling angle was 180 (°), and the size of the specimen was 15 cm × 2.54 cm.

[Comparative Example 1] Measurement of initial peeling force of protective film according to laser cutting

The initial peeling force was measured five times repeatedly in the same manner as in Example 1 except that the polishing process was excluded. The results of three measurements, excluding the maximum value and the minimum value, are shown in Table 1 below. The peeling force was measured using a TA-XT2 plus (mode: Tension, Trigger force: 5 gf) as the peeling force measurement device, the peeling speed was 300 mm / min, the peeling angle was 180 (°), and the size of the specimen was 15 cm × 2.54 cm.

[Comparative Example 2] Measurement of initial peeling force of protective film by mechanical cutting

The polarizing film is cut by a mechanical method (CNC), and a tape is attached to the protective film in order to remove the protective film located at the top of the polarizing film, and then the tape is pulled in the opposite direction (180 DEG) At this time, the force required to initially peel the protective film from the inner layer of the polarizing film located at the lower portion of the protective film, that is, the initial peeling force was repeatedly measured at room temperature five times (peel test) The results are shown in Table 1 below except for the maximum value and the minimum value. The peeling force was measured using a TA-XT2 plus (mode: Tension, Trigger force: 5 gf) as the peeling force measurement device, the peeling speed was 300 mm / min, the peeling angle was 180 (°), and the size of the specimen was 15 cm × 2.54 cm.

Initial peel force (gf / inch) 1 time Episode 2 3rd time Example 1 41.6 43.7 53.9 Example 2 96 54.6 82.3 Comparative Example 1 241.4 349.8 214.1 Comparative Example 2 46.5 54.7 49

[Examples 1 to 2, Comparative Examples 1 and 2] Evaluation of initial peel strength of protective film

As a result of measurement of the initial peeling forces of Examples 1 and 2 and Comparative Examples 1 and 2, as shown in Table 1, the initial peeling force (Comparative Example 1) at the time of detaching the protective film from the laser- Was about 7 times higher than the initial peeling force (Comparative Example 2) when the protective film was detached from the polarizing film cut by a mechanical method (CNC). On the other hand, when the protective film is removed after polishing the upper surface of the laser-cut polarizing film according to the present invention (Example 1), when the side of the laser-cut polarizing film is polished and then the protective film is removed As a result of measurement of the initial peeling force of Example 2, it was found that, even though the laser cutting was performed in the same manner, the protective film was removed without the polishing process (Comparative Example 1) ) Of the initial peeling force.

6 and 7 are graphs showing a comparison of the initial peeling force of the protective film according to various processes, that is, the initial peeling force, which is rapidly increased after laser cutting, is adjusted to a level similar to that obtained by mechanical cutting after the polishing process And it was found that even if only one of the upper surface and the side surface of the protective film is polished, a result similar to that obtained by mechanical cutting can be obtained. Therefore, when the method of removing the protective film of the laser-cut polarizing film and the polishing apparatus for implementing the same according to the present invention are used, the shoulder and the re-adherent layer on the polarized laser-cut polarizing film are removed, It is possible to easily release it from the container with a small force.

Claims (10)

Irradiating the polarizing film with a laser to cut the polarizing film;
Grinding and removing a shoulder and a recast layer on a polarizing film formed by irradiation of the laser; And
And removing the protective film from the polished polarizing film. The method according to claim 1, wherein the upper surface of the polarizing film is polished to remove the re-adherence layer formed on the outer surface of the shoulder and shoulder. The method according to claim 1, wherein the side of the polarizing film is polished to remove the re-applied layer formed along the taper. 4. The method of claim 3, wherein the side polishing is applied to one polarizing film or simultaneously after covering a plurality of polarizing films. The method according to claim 1, wherein the protective film is removed by a substrate containing a viscous component. The method of claim 1 or 5, wherein polishing the shoulder and the re-coherent layer of the polarizing film increases the area of attachment of the visco-sensitive substrate attached to the protective film, and the capping effect of the re- And the initial peeling force of the protective film is reduced. [6] The substrate according to claim 5, wherein the base material containing the viscous adhesive component is at least one selected from the group consisting of a tape containing a viscous component, a roller wound around the surface, a roller running continuously to the outer surface, And a roller coated on the surface of the polarizing film. A polishing apparatus for implementing a protective film removing method of a laser cut polarizing film according to claim 1. 9. The polishing apparatus of claim 8, wherein the polishing apparatus is used to remove the shoulder and the re-adherence layer formed on the laser-cut polarizing film. The polishing apparatus according to claim 8, wherein the polishing apparatus is selected from the group consisting of sand paper, a polishing roller surrounding a circumference of at least one roller, and a polishing wheel. Abrasive device.

Images