TWI501829B - Laser cutter, slitter provided with the laser cutter, and laser cutting method - Google Patents

Description

Laser cutting device, cutting machine with the same, and laser cutting method

The present invention relates to a laser cutting device and a slitting machine including the laser cutting device.

Polarizing films are widely used in liquid crystal panels and the like. In the processing step of the polarizing film, a half cut of a polarizing film in which only a polarizing film is cut in a laminate including a polarizing film, or a cutting of an end portion of a polarizing film, or the like is performed. Although the cutting of the polarizing film is performed by cutting with a blade, foreign matter such as a film residue is likely to be generated from the object to be cut. Since the foreign matter is mixed into the polarizing film, the yield is lowered.

Therefore, in recent years, laser cutting has been carried out. In the case of cutting with a laser, it is difficult to generate foreign matter such as a film scrap from the object to be cut compared to cutting with a blade. Thereby, the decrease in the yield can be suppressed. Therefore, this cutting method is extremely useful, and various methods have been developed (for example, Patent Documents 1, 2).

[First technical literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2008-302376 (published on December 18, 2008)

[Patent Document 2] Japanese Open Patent Gazette "Japanese Special Publication 2009-22978 (Opened on February 5, 2009)"

However, in the above-described cutting method of the polarizing film caused by the above-described laser, there is a problem that adverse effects are caused when the relatively moving polarizing film is cut. That is, in the case where the low output side of the laser is used, since the laser output is unstable, it is considered that there is a problem that the appropriate cutting cannot be performed.

The details are as follows. In the case of cutting the transferred polarizing film, most of the cutting is performed while conveying the polarizing film at a constant speed. In order to increase the production efficiency, the above-described constant speed is, for example, a speed of about 50 m/s. Therefore, from the viewpoint of improving the yield, the polarizing film can be cut at the time of acceleration before and after a certain speed and at the time of deceleration.

At a certain speed at which the transfer speed of the polarizing film is faster, the energy per unit time of irradiating the laser portion is reduced. Therefore, it is necessary to increase the output of the laser required for cutting. On the one hand, at a stage where the transfer speed of the polarizing film is slow, the energy per unit time of irradiating the laser portion is increased. As a result, there is a possibility that the cut surface of the polarizing film is deteriorated due to excessive heat. Therefore, it is necessary to suppress the output of the laser.

Here, in order to suppress the output of the laser, in the case where the low output side of the laser is used, there is a problem that the oscillation of the laser is unstable. Therefore, irregular fluctuations in the adjusted output and the inability to illuminate the energy of the polarizing film are sufficient. Therefore, even in the slower moving stage, the stable output does not incur the quality of the cut surface. A laser cutting device that degrades and cuts a polarizing film.

In connection with such a problem, Patent Document 2 discloses a laser processing method which increases the moving speed of the workpiece relative to the laser light and reduces the number of times the laser light is irradiated. According to this technique, the etching depth can be prevented from becoming too deep due to an increase in the power of the laser light due to the unstable output of the laser oscillator. However, in this technique, it is necessary to increase the relative moving speed of the workpiece and the laser light, and in the case where the relative speed is small, there is a problem that it is difficult to apply.

The present invention has been made in view of the above problems, and an object thereof is to provide a laser cutting apparatus in which the output of laser light is not unstable and does not cause deterioration in the quality of the cut surface of the polarizing film.

The laser cutting device of the present invention is a laser cutting device that irradiates laser light onto a polarizing film and cuts the laser cutting device, and is characterized in that: a laser beam oscillating device is provided to oscillate the laser light; a curved mirror that reflects the laser light oscillated by the laser oscillating machine to the polarizing film; a concentrating lens disposed between the polarizing film and the curved mirror, and concentrating the laser light, wherein A beam splitter that transmits and reflects the laser light is provided between the curved mirror and the condensing lens.

In the laser cutting device of the present invention, the laser light is branched into a transmitted light and a reflected light by a spectroscope, and the polarized film is cut by the transmitted light. Therefore, even if the output of the laser oscillating machine is increased, the energy of the laser light irradiated to the polarizing film can be reduced. As a result, the laser oscillating machine can be used at a high output even in the case where the relative speed of the laser cutting device and the polarizing film is reduced. That is, an output stability which is advantageous when using the high output side of the laser oscillating machine can be obtained. On the other hand, since the energy of the polarizing film is reduced by the spectroscope, deterioration of the quality of the cut surface which is a problem when the high output side of the laser oscillator is used can be suppressed.

The laser cutting device of the present invention, as described above, comprises: a laser oscillating machine that oscillates the laser light; and a curved mirror that reflects the laser light oscillated by the laser oscillating machine to the polarizing film; A concentrating lens is disposed between the polarizing film and the curved mirror to condense the laser light, and a spectroscope for transmitting and reflecting the laser light is provided between the curved mirror and the condensing lens.

Therefore, even in the case where the relative speed of the laser cutting device and the polarizing film is small, the laser oscillator can be used at a high output. That is, an output stability which is advantageous when using the high output side of the laser oscillating machine can be obtained. On the other hand, since the energy of the polarizing film can be reduced by the spectroscope, the effect of suppressing deterioration of the quality of the cut surface which is a problem when using the high output side of the laser oscillator can be achieved.

An embodiment of the present invention will be described below based on the first to fourth figures.

[Cutting device]

The first figure shows a cross-sectional view of a laser cutting device 10 of the present invention. The laser cutting device 10 includes a laser beam oscillator 1, a beam expander 2, a bending mirror 3, a beam splitter 4, and a collecting lens 5.

The laser light oscillating machine 1 is a member that oscillates the laser light, and is not particularly limited. For example, CO ₂ laser (carbon dioxide laser), UV laser, semiconductor laser, YAG laser, excimer laser, etc. can be used. Among these, it is preferable to have a high output and cut the polarizing film into a suitable CO ₂ laser.

In the case where the output of the laser oscillating machine 1 is low, the output of the laser light is apt to be unstable. Therefore, the output is preferably a high output. On the other hand, when the output is too high, quality deterioration occurs on the cut surface of the polarizing film due to excessive thermal expansion or the like.

The specific output of the laser oscillator 1 can be suitably adjusted in accordance with the thickness of the polarizing film 6, the transport speed of the polarizing film 6, and the ratio of transmission and reflection by the spectroscope 4 to be described later. From these viewpoints, the output of the laser oscillator 1 is preferably 30 W or more and 400 W or less. Further, in the case where the output of the laser oscillating machine 1 is low, although the output is unstable, in particular, if it is less than 30 W, it tends to be unstable.

The frequency of the laser light to be irradiated can be appropriately changed depending on the output of the laser oscillator 1, the thickness of the polarizing film 6, and the transport speed of the polarizing film, but it can be approximately 5 kHz or more and 100 kHz or less.

The laser cutting device 10 is provided with a beam expander 2 as an appropriate form. The beam expander 2 is a member that expands the laser light into a parallel beam, and a well-known beam expander can be used. The diameter of the laser light L1 is expanded by, for example, about 2 times to 10 times by the beam expander 2 to become the laser light L2. When the laser light L6 is irradiated to the polarizing film 6, the laser light is easily focused by expanding the diameter of the laser light.

The curved mirror 3 is a member that reflects the laser light oscillated from the laser oscillator 1 to the polarizing film 6. The laser cutting device 10 is provided with one curved mirror 3. However, if the laser light L2 is used as the laser light L3 and is reflected to the polarizing film 6, it may be plural.

The output of the laser oscillating machine in a general laser cutting device will be described using the second figure. The second graph shows a graph of the relationship between the time t and the output w of the laser oscillator when the polarizing film is transported. When the polarizing film is conveyed while being cut, the polarizing film is first accelerated (acceleration region), and then a certain speed suitable for cutting (fixed speed region) is set, and the polarizing film is decelerated (deceleration region) to complete the cutting of the polarizing film. .

In the acceleration region and the deceleration region, since the speed of the polarizing film is reduced, the energy per unit time of the polarizing film increases as long as the irradiation conditions are the same. Therefore, it is necessary to reduce the output of the laser oscillator. Therefore, in one of the acceleration region and the deceleration region, the output of the laser oscillating machine is low, and the output of the laser oscillating machine is unstable (unstable region). As a result, in the acceleration region and the deceleration region, uncut may occur due to the unstable output of the laser oscillating machine. There is a limitation as described above, and in a general laser cutting device, in the acceleration region and the deceleration region, the output of the laser oscillator cannot be improved.

On the other hand, in the laser cutting device 10 of the present invention, the spectroscope 4 is provided between the curved mirror 3 and the collecting lens 5. The spectroscope 4 is a member that transmits and reflects the above-described laser light L3, and a well-known spectroscope can be used. The laser light L3 is branched by the spectroscope 4 into a laser light L4 that is transmitted light and a laser light L5 that is reflected light.

The ratio of the transmission and reflection of the laser light by the spectroscope 4 is not particularly limited, but is preferably adjusted in accordance with the output of the laser oscillator 1, the thickness of the polarizing film 6, and the transport speed of the polarizing film 6. In general, the output of the above-described laser oscillating machine is 30 W or more and 400 W or less, and the ratio of the laser beam transmitting and reflecting by the spectroscope is preferably 3:7 to 7:3. As long as it is within the above-described setting range, the laser cutting device 10 can be suitably used for cutting the polarizing film.

In the laser cutting device 10, the laser light L3 is branched into the transmitted light and the reflected light by the spectroscope 4, and the polarizing film 6 is cut by the transmitted light. Therefore, according to the laser cutting device 10, even if the output of the laser oscillating machine 1 is large, the energy of the laser light L6 irradiated to the polarizing film 6 can be reduced. That is, even in the acceleration region and the deceleration region, the laser oscillator 1 can be used at a high output, and the stability of the output which is advantageous when the high output side of the laser oscillator 1 is used can be obtained. On the other hand, since the energy applied to the polarizing film by the spectroscope 4 is reduced, deterioration of the quality of the cut surface which is a problem when the high output side of the laser oscillator 1 is used can be suppressed.

The laser light L5 is condensed on the polarizing film 6 by the condensing lens 5. The condensing lens 5 is not particularly limited, and a spherical lens, an aspherical lens, or the like can be used. Since the dicing width can be determined by the condensing diameter of the laser light L6, the condensing diameter of the laser beam L6 is preferably 5 μm or more and 500 μm or less, and more preferably 10 μm or more and 400 μm or less in the case of cutting the polarizing film.

A well-known polarizing film can be used for the polarizing film 6 to be cut by the laser cutting device 10. In the case of the polarizing film of the present invention, a polarizing film of an extra long shape is usually used, but a short or plate-shaped polarizing film can also be used. The extra long shape means that the length of the polarizing film 6 in the cutting direction is 10 m or more, and the short type means 2 m or more and less than 10 m, and the plate shape means 10 cm or more and less than 2 m.

Specifically, as the polarizing film 6, a TAC (triethylenesulfonyl cellulose) film, a COP (cycloolefin polymer) film, or the like is bonded to both surfaces of the polarizing element film as a protective film, and the laser cutting device 10 is used. The structure of the TAC film on the reverse side of the protective film is formed by an adhesive. In the polarizing film 6, the polarizing film of the center is a film obtained by dyeing a polyvinyl alcohol film with iodine or the like, and bonding a protective film such as TAC to an extended film or the like. Further, a partially-formed polyvinyl alcohol-based film, an ethylene-vinyl acetate copolymer-based partially saponified film, a hydrophilic polymer film such as a cellulose-based film, or the like, and a dehydrated material of polyvinyl alcohol may be used. Or a polyene oriented film or the like of a polychlorinated dehydrochlorination treatment or the like, in place of the above polyvinyl alcohol film.

The total thickness of the polarizing film 6 and the protective film is not particularly limited, and may be 100 μm or more and 500 μm or less. Further, in the polarizing film 6, the thickness of the polarizing element film is approximately 10 μm or more and 50 μm or less. Further, in the practical and problem-free range of the polarizing film 6, other layers may be further contained in addition to the above three layers.

As the protective film, a polyester film, a polyethylene terephthalate film or the like can also be used. The thickness and width of the protective film are not particularly limited. However, from the viewpoint of using a protective film as a polarizing film, for example, a protective film having a thickness of 5 μm or more and 50 μm or less and a width of 200 mm or more and 1500 mm or less can be suitably used.

The cutting of the polarizing film 6 by the laser cutting device 10 is performed while moving the laser cutting device 10 or the polarizing film 6. Thereby, a cut surface can be formed on the polarizing film 6. Specifically, the slitter can be cut while moving the polarizing film as described later. Further, in the case where the laser cutting device 10 is fixed and the cutting is performed while the polarizing film 6 is being conveyed, it is preferable to perform stable cutting.

In the present invention, "cutting" a polarizing film means to "cut at least a portion of the polarizing film", and also includes processing in which the polarizing film is formed to a predetermined depth. For example, the cutting, half-cutting, marking processing, etc. of the ends of the polarizing film are also included in the "cutting" behavior.

[cutting machine]

Next, the slitter 20 of the present invention will be described. The third figure shows a cross-sectional view of the slitter 20 of the present invention. The slitter 20 includes a laser cutting device 10, a winding unit 11, a conveyance roller 12‧12a‧12b‧12c‧12d‧12e‧12f (hereinafter referred to as "12 to 12f"), a length gauge 14, and a winding section 13a‧13b.

The winding unit 11 holds the polarizing film 6 of an extra long shape and winds up the conveyance roller 12 . The winding unit 11 is not particularly limited, and a well-known winding unit can be used. In the slitter 20, a cylindrical shaft is used as the winding portion 11, and a paper tube, a plastic tube, or the like around which the polarizing film 6 is wound can be held. The side surface of the winding portion 11 is provided with a rotating device for rotating the winding portion 11, and the winding device 11 is rotated by the rotating device, and the polarizing film 6 is wound in the conveying direction. The tension applied to the polarizing film 6 and the conveying speed of the polarizing film can be set by the rotating device. Further, the height of the winding portion 11 and the position of the winding portion 11 in the horizontal direction can be appropriately adjusted.

The winding portion 11 is provided at one place, but may be provided at two places like the winding portion 13a‧13b. Thereby, before the polarizing film 6 of the winding portion 11 is completely wound, it can be connected to the polarizing film of the other winding portion, and the exchange time of the polarizing film before processing can be reduced.

In the slitter 20, the conveyance rollers 12 to 12f are disposed along the conveyance path of the polarizing film 6. The arrangement place of each of the conveyance rollers can be appropriately changed in accordance with the conveyance path of the polarizing film 6. The conveyance roller is not particularly limited, and a well-known member can also be used. Further, the diameter and width of the conveyance roller are not limited. Usually, the width of the conveying roller is about 1.5 m to 2.5 m. Further, the slitter 20 may be provided with a touch roll that causes the polarizing film 6 to abut against the conveyance roller.

A laser cutting device 10 is provided between the conveyance roller 12b and the conveyance roller 12c. Such a laser cutting device 10 can be placed between the winding portion 11 and the winding portion 13a. The structure of the laser cutting device 10 is as described above.

The winding portion 13a‧13b is a member that winds up the cut polarized film 6. In the same manner as the winding portion 11, the side surface of the winding portion 13a‧13b is not shown, but includes a rotating device that rotates the winding portion 13a‧13b, and the winding portion 13a‧13b is rotated by the rotating device, and the polarizing film 6 is rotated. It is wound up toward the conveying direction. The tension applied to the polarizing film 6 and the conveying speed of the polarizing film can be set by the rotating device. Further, the position in the height and the horizontal direction of the winding portion 13a‧13b can be appropriately adjusted.

According to the slitter 20, the polarizing film 6 is conveyed by the winding portion 11 and the winding portion 13a. The transport speed of the polarizing film is not particularly limited, but may be, for example, 1 m/s or more and 100 m/s or less.

The fourth figure shows a plan view of the cutting process of the polarizing film 6. As shown in (a) to (c) of the fourth drawing, the slit S is formed in the polarizing film 6 by the laser cutting device 10 as the polarizing film 6 is conveyed. In the fourth figure, the laser cutting device 10 is provided to cut the periphery of the end portion of the polarizing film 6. This is a case where the end portion of the polarizing film 6 is slit. The installation position of the laser cutting device 10 is not particularly limited as long as it can irradiate the laser light to the polarizing film 6. For example, when the laser cutting device 10 is provided to irradiate the laser light to the central portion of the polarizing film 6, the polarizing film 6 can be divided into two.

Since the slitting machine 20 of the present invention includes the laser cutting device 10, the polarizing film 6 can be accelerated or decelerated, that is, even if the conveying speed of the polarizing film is reduced, the laser oscillator can be used at a high output. 1. As a result, an output stability which is advantageous when the high output side of the laser oscillating machine 1 is used can be obtained. On the other hand, since the energy of the polarizing film is reduced by the spectroscope 4, it is possible to suppress quality deterioration in the cut surface of the polarizing film which is a problem when the high output side of the laser oscillator 1 is used.

Further, the present invention contains the following aspects.

In the laser cutting apparatus of the present invention, the output of the laser oscillating machine is 30 W or more and 400 W or less. Preferably, the ratio of the laser beam transmitted and reflected by the spectroscope is 3:7 to 7:3.

The output of the above-described laser oscillating machine is 30 W or more and 400 W or less. As long as the ratio of the laser beam transmitting and reflecting by the spectroscope is within the above range, it can be suitably used for cutting the polarizing film.

Further, in the laser cutting apparatus of the present invention, the above-described laser oscillating machine is preferably a CO ₂ laser oscillating machine.

The CO ₂ laser oscillator is a high output and is suitable for the cutting of polarized films.

Moreover, the slitting machine of the present invention includes: a winding unit that is one of the wound polarizing films; and a winding unit that retracts the polarizing film, and the laser cutting device is provided between the winding unit and the winding unit .

Since the slitting machine of the present invention is provided with a laser cutting device, the laser beam oscillating machine can be used at a high output even when the conveying speed of the polarizing film is reduced. As a result, an output stability which is advantageous when using the high output side of the laser oscillating machine can be obtained. On the other hand, since the energy of the polarizing film is reduced by the spectroscope, the deterioration of the quality of the cut surface of the polarizing film which is a problem when the high output side of the laser oscillating machine is used can be suppressed.

In addition, the present invention is not limited to the above-described embodiments, and various modifications can be made as far as the scope of the claims is concerned, and the embodiments obtained by separately combining the technical means of the different embodiments are also included in the present invention. Within the technical scope of the invention.

[Examples]

[Example 1]

The slit film 20 is cut using the slitting machine 20 described in the third drawing. The polarizing film 6 is formed from a condenser lens 5 closest to the laser cutting device 10, and sequentially has a PET film (38 μm), an adhesive layer (22 μm: the adhesive layer and the protective film are simultaneously peeled off), a TAC film (80 μm), and a poly layer. A vinyl alcohol film (30 μm) and a COP (cycloolefin polymer) film (70 μm) were used as a protective film, and in the COP film, a PET film (38 μm) as a separator film was laminated via an adhesive layer.

First, from the state in which the polarizing film 6 is stationary, the polarizing film 6 is accelerated to 50 m/s after 5 seconds by the rotating device of the winding portion 11 and the winding portion 13a. During the period of acceleration to 50 m/s, the polarizing film 6 was cut under the following conditions.

Laser oscillating machine: CO ₂ laser

Output of laser oscillating machine: 20W or more and 280W or less

Laser wavelength: 9.4μm

Laser frequency: 20kHz

Concentration diameter of L6: 54μm

Ratio of transmitted light to reflected light: 5:5

[Comparative Example 1]

The comparative cutting device after the spectroscope 4 is removed by the laser cutting device 10 of the slitter 20 performs cutting of the polarizing film 6. The structure of the polarizing film 6 is the same as that of the first embodiment. In the same manner as in the first embodiment, the polarizing film 6 was accelerated to 50 m/s. Further, the conditions for cutting are as follows.

Laser oscillating machine: CO ₂ laser

Output of laser oscillating machine: 10W or more, 140W or less

Laser wavelength: 9.4μm

Laser frequency: 20kHz

Concentration diameter of L6: 54μm

The fifth drawing shows a side view of the cut polarizing film 6 in Example 1 and Comparative Example 1. The fifth (a) is a polarizing film 6 of the first embodiment, and the fifth (b) is a polarizing film 6 of the comparative example 1. From the results, it was found that the polarizing film 6 of Comparative Example 1 was deformed in the cross section due to thermal expansion. Moreover, we have also observed that the PET film on the top is agglomerated by thermal expansion. On the other hand, in the polarizing film 6 of Example 1, unlike the comparative example 1, no deformation occurred on the cut surface. Furthermore, the PET film on the top does not produce agglomerates. According to the slitter (laser cutting device) of the present invention, deterioration in quality of the cut surface of the polarizing film can be suppressed even at a conveying speed of 50 m/s, and the superiority of the present invention is extremely clear.

Furthermore, it was tested whether or not the cut surface of the polarizing film 6 was good. The test method is to peel off the separator film from the cut polarizing film, and adhere the COP film surface to the glass plate via the adhesive layer. When the COP film is deformed, air bubbles are mixed between the COP film and the glass plate. After the polarizing film 6 after the dicing of the first embodiment and the comparative example 1 was tested, no mixing of the bubbles was observed after the polarizing film 6 of the first embodiment was adhered, but in the polarizing film 6 of Comparative Example 1, The mixing of the bubbles after the adhesion was observed. This is the result of the deformation state of the COP film of the fourth layer in the polarizing film 6 due to the above. The results demonstrate the superiority of the present invention.

[Industrial Availability]

In the laser cutting device of the present invention, a polarizing film can be used as a suitable cutting object. Thus, the present invention can be widely utilized in the field of using a polarizing film.

1. . . Laser oscillating machine

2. . . Beam expander

3. . . Curved mirror

4. . . Splitter

5. . . Condenser lens

6. . . Polarized film

10. . . Laser cutting device

11. . . Rolling department

12, 12a, 12b, 12c, 12d, 12e, 12f. . . Transport roller

13a, 13b. . . Reeling department

14. . . Length gauge

20. . . Cutting machine

L1~L6. . . laser

S. . . Gap

The first figure shows a cross-sectional view of the laser cutting apparatus of the present invention.

The second graph shows a graph of the relationship between time t and output w in the case of carrying a polarizing film.

The third figure shows a cross-sectional view of the slitter of the present invention.

The fourth figure shows a plan view of the cutting process of the polarizing film caused by the slitter of the present invention.

Fig. 5 is a side view showing a polarizing film cut in Example 1 and Comparative Example 1.

1‧‧‧Laser light oscillating machine

2‧‧‧beam expander

3‧‧‧Bend mirror

4‧‧‧Abeam splitter

5‧‧‧ Concentrating lens

6‧‧‧ polarizing film

10‧‧‧Laser cutting device

L1 to L6‧‧‧Laser light

Claims (6)

A laser cutting device, which is a laser cutting device that irradiates laser light on a relatively moving polarizing film and is pre-cut, comprising: a laser oscillating machine that oscillates the laser light; and a curved mirror The laser light oscillated by the laser oscillator is reflected to the polarizing film; a concentrating lens is disposed between the polarizing film and the curved mirror to condense the laser light, wherein between the curved mirror and the collecting lens a beam splitter for transmitting and reflecting the laser light, the beam splitter reducing the energy of the laser light by directing only the transmitted light to the polarizing film; and accelerating and decelerating the relatively moving polarizing film The polarizing film is also cut; the output of the laser oscillator is 30 W or more and 400 W or less, so that the ratio of the transmitted and reflected laser light of the spectroscope is 3:7 to 7:3. The laser cutting device of claim 1, wherein the laser oscillating machine is a CO ₂ laser oscillating machine. A laser cutting device according to any one of claims 1 to 2, wherein a beam expander is provided between the laser oscillating machine and the curved mirror, the beam expander expands the laser light into a parallel beam . A slitting machine comprising: a winding portion for winding a polarizing film; and a winding portion for winding a polarizing film, wherein the winding portion and the winding portion are provided with a patent application A laser cutting device according to any one of items 1 to 3. A slitting machine comprising: a winding portion for winding a polarizing film; and a winding portion for winding a polarizing film; wherein a laser cutting is provided between the winding portion and the winding portion The device has two winding portions; the laser cutting device is a laser cutting device that irradiates laser light on a relatively moving polarizing film and is pre-cut, and has: a laser oscillating machine for oscillating laser light; a curved mirror for reflecting the laser light oscillated by the laser oscillating machine to the polarizing film; and a concentrating lens disposed for the polarizing film and the curved mirror And concentrating the laser light, wherein a beam splitter for transmitting and reflecting the laser light is provided between the curved mirror and the condensing lens, and the beam splitter directs the transmitted light to the polarizing film. The energy of the laser light is reduced; the polarizing film is also cut during acceleration and deceleration of the relatively moving polarizing film. A laser light cutting method, which is a laser cutting method for irradiating laser light on a polarized film to be carried and cutting, comprising the steps of: transporting a polarizing film; oscillating the laser light; and transmitting and reflecting the laser light Directly transmitting the transmitted light to the polarizing film to reduce the energy of the laser light irradiated to the polarizing film; wherein the cutting of the polarizing film is performed during acceleration and deceleration of the transported polarizing film; The step of illuminating the light is performed at an output of 30 W or more and 400 W or less; the step of reducing the energy of the laser light is performed in a range of a ratio of transmission and reflection of 3:7 to 7:3.