TW201444630A - Method to cut off the resin plate adhered to the glass substrate - Google Patents

Abstract

The present invention provides a cut-off method by laser beam, which can suppress the thermal damage to the glass substrate, and can make the cut-off surface of the rein plate adhered to the glass substrate as steep as possible. The method to cut off the resin plate 2 by irradiating the laser beam B onto the resin plate 2 adhered to the glass substrate 1 is: to irradiate the laser beam B in the state that the focal point P defocuses above the resin plate 2, allocate the shielding plate 3 to shield the laser beam B along the predetermined cut-off line S of mother substrate A and to expose the predetermined cut-off line S, so that it is configured to have only the peak portion B1 in the light intensity distribution of laser beam B irradiate the predetermined cut-off line S on the surface of resin plate 2, the other portion B2 is barred by the shielding plate 3.

Description

Cutting method of resin plate adhered to glass substrate

The present invention relates to a cutting method for cutting a resin sheet adhered to a glass substrate by irradiation of a laser beam. For example, the present invention is used as a cutting method in which a polarizing plate is cut by a laser beam in a liquid crystal display panel (LCD) in which a resin polarizing plate is adhered to a glass substrate.

Conventionally, a liquid crystal display panel in which a polarizing plate (polarizing film) made of a PET resin or the like is adhered to one surface or both surfaces of a glass substrate is known. A method of manufacturing such a liquid crystal display panel is disclosed, for example, in Patent Document 1. In the method disclosed in Patent Document 1, first, each unit panel is cut out from a large-area liquid crystal mother substrate in which a plurality of unit panels are patterned, and a separately formed polarizing plate is attached to each of the unit panels.

In the above method, since it is necessary to adhere the polarizing plate to each unit panel, it takes a considerable amount of time in this step. In addition, it is necessary to correctly position and adhere the polarizing plate of the same size to the glass substrate, which requires time and is required to be positioned, and it is easy to cause a problem due to positional deviation.

Therefore, Patent Document 2 discloses a method in which the applicant first attaches a polarizing plate to the entire surface of a large-area liquid crystal mother substrate, and then cuts the polarizing plate by a laser beam along a line to cut. According to this, the polarizing plate can be matched with the glass substrate of the unit panel with high precision, and can be adhered to a plurality of unit panels at one time. In addition, by placing the ITO film in the glass Between the substrate and the polarizing plate, the light beam is reflected by the ITO film when the light beam is irradiated, and thermal damage to the glass substrate is suppressed.

Patent Document 1: Japanese Patent Laid-Open Publication No. 2002-023151

Patent Document 2: Japanese Laid-Open Patent Publication No. 2011-178636

Generally, in the case where the laser beam is scanned and the polarizing plate is cut, the laser beam is scanned with a predetermined intensity distribution. As shown in Fig. 5(a), the light intensity distribution of the irradiation beam is a mountain-like distribution (Gaussian distribution) in which the center portion of the optical axis is strong and the outside is weak. The laser beam can also form a circular beam spot, and an elliptical beam spot having a predetermined major axis diameter and short axis diameter can also be formed.

Therefore, in the case where the focus of the laser beam is irradiated so as to be adhered to the surface of the polarizing plate 12 of the glass substrate 11, as shown in FIG. 5(b), it is formed by melting or ablation. The groove 13 is substantially in the reverse shape of the light intensity distribution (the same as the heat intensity distribution of the irradiation surface). Thereafter, the substrate is transported to the next step, and when the glass substrate 11 is divided into unit panels along the center of the trench 13, as shown in FIG. 5(c), the cut surface of the polarizing plate 12 becomes an inclined surface. As a result, in the vicinity of the end surface of the glass substrate 11, the inclined region in which the thickness of the polarizing plate 12 is gradually thinned is formed at a predetermined width L1.

However, in the case where the divided unit panel is formed into a product, it is preferable that the width L1 of the inclined region is as small as possible. That is, it is preferable that the end of the polarizing plate 12 is separated as close as possible to the end of the glass substrate 11.

As a method for reducing the width L1 of the inclined region, the beam spot located on the surface of the polarizing plate 12 is reduced in diameter. The laser beam becomes a steep light by concentrating it into a smaller light beam Degree distribution. As described above, since the groove 13 has an inverted shape corresponding to the light intensity distribution, the width L1 of the narrower inclined region can be obtained as a result. On the other hand, since the beam spot is concentratedly irradiated with a strong light intensity, thermal damage is also applied to the glass substrate 11 directly under the polarizing plate 12. The thermal destruction of the glass substrate 11 is greatly impaired because the strength of the glass substrate 11 itself is lowered to greatly impair the value of the product.

In order to obtain a high-quality unit panel, it is preferable to reduce the width L1 of the inclined region as much as possible without causing thermal damage to the glass substrate, and specifically, to make L1 50 μm or less.

In view of such a problem, in the above-mentioned Patent Document 2, the ITO film is placed between the glass substrate and the polarizing plate, and is reflected by the ITO film when the laser beam is irradiated, thereby suppressing the laser beam to the glass. Thermal destruction of the substrate.

However, if an ITO film is to be incorporated, there is a problem that the configuration of the liquid crystal panel is complicated, and the manufacturing steps such as ITO vapor deposition are also increased to increase the cost.

The inventors of the present invention shield the peripheral portion of the laser beam (the two of the scribe lines) by performing defocusing at a position away from the focus without imparting thermal damage to the glass substrate located under the polarizing plate. The side or the one side) is prevented from being irradiated to the polarizing plate, and the inclination of the cut surface of the polarizing plate is found to be steep, and the present invention has been completed.

An object of the present invention is to provide a method for cutting a resin sheet using a laser beam, which can omit the step of forming a reflective layer using an ITO film, and can suppress thermal damage to a glass substrate due to a laser beam. Further, it is possible to make the inclined region of the width L1 of the resin sheet such as a polarizing plate adhered to the surface of the glass substrate steep.

In order to solve the above problems, the following technical solutions are proposed in the present invention. means.

In other words, the cutting method of the present invention is a method in which the resin sheet is adhered to the resin sheet of the underlying substrate such as glass, and the laser beam is irradiated while being relatively moved along the line to cut.

Further, the light intensity distribution of the laser beam irradiated to the resin plate is irradiated to a portion of a peak portion of a substantially constant intensity near the center of the optical axis of the light beam and a tail portion which is gradually attenuated on the outer side thereof. The focus of the beam is irradiated from the surface of the resin sheet in a state of being defocused in the height direction.

Further, a shielding member that shields a laser beam that is irradiated onto the resin sheet is disposed such that the line to be cut is exposed and disposed adjacent to the line to cut, and among the laser beams, The laser beam of the peak portion illuminates the line to cut, and the laser beam of the tail portion is blocked by the shielding member.

Among them, it is preferable that the laser beam is a CO ₂ laser.

According to the present invention, since the laser beam irradiated onto the resin plate (polarizing plate) is in a defocused state, the peak of the light intensity distribution is relatively low as compared with the position where the light beam is concentrated. Therefore, it is possible to suppress thermal damage imparted to the glass substrate when the polarizing plate is cut, compared to processing at a position where the light beam is concentrated. On the other hand, when the laser beam is irradiated, the tail value portion of the light intensity distribution of the laser beam is blocked by the shielding plate, so that the cut end surface of the polarizing plate cut along the end portion of the shielding plate becomes a steep inclined surface. It is possible to obtain a high quality product having a nearly perpendicular cut end face.

A‧‧‧LCD mother substrate

A1‧‧‧unit panel

B‧‧‧Laser beam

C‧‧‧ trench

P‧‧‧The focus of the laser beam

1‧‧‧ glass substrate

2‧‧‧Polar plate (resin plate)

3‧‧‧shading board

Fig. 1 is a view showing an example of a cutting method of the present invention.

Fig. 2 is a view showing a processing example in the case where a shielding plate is not used.

Fig. 3 is a view showing the steps of the cutting method shown in Fig. 1.

Fig. 4 is a view showing another embodiment of the cutting method of the present invention.

Fig. 5 is a view showing a pattern of a groove formed by a conventional laser beam irradiation method.

Hereinafter, the cutting method of the present invention will be described in detail based on the drawings.

1(a) is a cross-sectional view showing the glass substrate 1 in the liquid crystal mother substrate A before the unit panel is cut out, and the polarizing plate 2 adhered thereto, and the liquid crystal mother substrate A is irradiated with a laser beam. The case where B is divided into the left and right unit panels A1 and A1 from the cutting planned line S will be described as an example.

As shown in Fig. 1(a), in a defocused state in which the focus P of the laser beam B which is to suppress thermal destruction of the glass substrate 1 is shifted above (or below) the liquid crystal mother substrate A, The laser optical system (outside the figure) is disposed above the cut-off planned line S. In the case of the present embodiment, the polarizing plate 2 is formed of PET resin or the like, and the thickness of the glass substrate 1 is about 0.7 mm, and the thickness of the polarizing plate 2 is about 0.2 mm. Further, the position of the focus P of the defocused laser beam B, that is, the distance H between the focus P and the upper surface of the polarizing plate 2 is set to be about 2 mm.

As the laser beam B to be used, it is preferable to use a CO ₂ laser having a wavelength which is excellent in absorption efficiency for the polarizing plate 2, for example, having a wavelength of 9.4 μm or 10.6 μm.

Further, as shown in Fig. 1(b), in a state where the vicinity of the line to cut S is partially exposed, a shielding plate for shielding the laser beam B is disposed on both sides or one side thereof along the line to cut S. (shielding member) 3. In the shielding plate 3, a material such as a glass plate or a shim tape that cannot be transmitted by a CO ₂ laser is used.

For convenience of explanation, the processing state when the shield plate 3 is not used will be briefly described. FIG. 2 is a view showing a state in which the laser beam B irradiated in a defocused state is directly irradiated to the polarizing plate 2 without using the shielding plate 3.

The laser beam B irradiated on the upper surface of the polarizing plate 2 is positioned lower than the position of the focus P, that is, in a state of defocusing, and the beam diameter is wider than the focal point P. Therefore, as shown in FIG. 2(b), the light intensity distribution on the polarizing plate 2 is a peak portion of the optical axis center of the laser beam B, and is compared with the focal point P (refer to FIG. 5(a)). A mountain-like form (a Gaussian distribution of a gentle slope) that slowly attenuates the tail toward the outer periphery is extracted. When the laser beam B is irradiated onto the polarizing plate 2, the groove C1 formed in the polarizing plate 2 has a shape in which the light intensity distribution is reversed as shown in Fig. 2(a). Therefore, the cut surface of the polarizing plate 2 which is divided along the cutting planned line S forms an inclined surface of the gentle slope, and the cutting quality of the polarizing plate 2 is not preferable. Although it is also based on the shape of the product after the break, in general, the closer the inclined surface is to the vertical, the higher the quality.

In the present invention, as shown in Fig. 3 (a), the shielding plate 3 (shielding member) is disposed along the line to cut S in a state in which the vicinity of the line to cut S is exposed, so that only the light intensity is made. The light of the peak portion B1 near the center of the optical axis in the distribution is irradiated onto the planned cutting line S, and the other tail portion B2 is blocked by the shielding plate 3. The distance L between the end surface of the shielding plate 3 and the planned cutting line S is preferably about 10 to 200 μm, more preferably about 20 to 100 μm.

The groove C is formed in the polarizing plate 2 as shown in Fig. 3(b) by moving the laser beam along the line to cut S as described above. The laser beam is irradiated only by the peak portion B1 of the light intensity distribution to the portion of the cut line S between the left and right shield plates 3, 3, and the tail portion B2 is blocked by the shield plate 3. The laser beam that is irradiated on the cut line S is defocused Since the light is irradiated, the light intensity is weakened and the intensity is substantially constant, and the glass can be suppressed, as compared with a laser beam having a higher peak intensity of the concentrated light when the focus is placed on the polarizing plate 2 Thermal destruction of the substrate 1. In the line S of cutting, the laser beam of the peak portion B1 is irradiated, and the groove C can be formed by melting or denuding.

Further, on the irradiation surface, the tail portion B2 of the light intensity distribution of the laser beam is blocked by the shielding plate 3, and the light having the peak intensity B1 of the light intensity of a certain intensity is irradiated onto the polarizing plate 2, so that the irradiation portion is completed. Uniform processing (erosion or melting) is performed using substantially uniform light energy, and the groove C after the processing forms a steeply inclined surface on which the left and right side walls are straightened as shown in Fig. 3(c). Therefore, when the glass substrate 1 is divided into the unit panels A1 and A1 along the line to cut S in the next step, the end faces of the polarizing plates 2 form a steep inclined surface, and the width L1 of the inclined regions can be made small. That is, according to the present invention, it is possible to suppress thermal damage to the glass substrate and form a steep inclined surface on the polarizing plate. Conventionally, these effects can be achieved only under mutually contradictory conditions (defocusing or concentrating). However, according to the present invention, it is possible to achieve a processing result that has not been both beautiful in the past by one-time scanning.

Here, a specific processing example using the present invention will be described. In the liquid crystal mother substrate having a thickness of 0.7 mm and a thickness of 0.2 mm of the polarizing plate 2 made of resin, the shielding plate 3 having a thickness of 0.5 mm is attached, and the end faces of the shielding plate 3 and the cutting schedule are prepared. The interval L of the line S is set to 50 μm, the distance H between the focus P of the laser and the defocus on the polarizing plate 2 is set to 2 mm, and the polarizing plate 2 is cut by a CO ₂ laser.

As a result, the width L1 of the inclined region can be improved to 38 μm smaller than the target 50 μm.

Further, for comparison, as a result of the same laser irradiation in which the shielding plate 3 was not attached, the width L1 of the inclined region was 80 μm or more.

Next, a second embodiment will be described. FIG. 4 shows a state in which the polarizing plate 2 adhered in a state of being overhanged from the end surface of the glass substrate 1 is cut.

In this case, as shown in FIG. 4(a), the end portion 2a cut from the polarizing plate 2 is to be discarded, and therefore, the shielding plate 3 is disposed only on the cutting line S along the end surface of the glass substrate 1. Glass substrate 1 side. Then, similarly to the above-described embodiment, the laser beam B is irradiated onto the polarizing plate 2 along the line to cut S in a defocused state. As a result, as shown in FIG. 4(b), the side wall of the groove C' formed in the polarizing plate 2 has a peripheral portion in the heat intensity distribution as in the previous embodiment. The (tail value portion) B2 is blocked by the shielding plate 3, so that a steep inclined surface is formed, and the opposite side forms an inclined surface of the gentle slope. The polarizing plate 2 on the side of the inclined surface of the gentle slope is discarded as the end material 2a.

As a result, as shown in FIG. 4(c), the cut end surface of the polarizing plate 2 adhered to the glass substrate 1 can be cut in a state of being aligned with the end surface of the glass substrate 1, and the polarizing plate 2 can be cut. The width L1 of the inclined region of the end face becomes small.

Although the representative embodiments of the present invention have been described above, the present invention is not necessarily limited to the above embodiments. For example, as a resin plate to be cut, a polarizing plate adhered to a glass substrate of a liquid crystal display panel is disclosed, but a substrate which is a substrate of the bottom layer, even if it is a substrate other than glass, is also subjected to thermal damage when irradiating a laser beam. The present invention can be utilized. Further, in the present invention, it is possible to appropriately modify and change the scope of the invention without departing from the scope of the patent application.

The present invention is used when cutting a resin sheet adhered to a glass substrate like a polarizing plate of a liquid crystal display panel.

A‧‧‧LCD mother substrate

A1‧‧‧unit panel

B1‧‧‧ peak section

B2‧‧‧ tail value part

C‧‧‧ trench

L‧‧‧ interval

L1‧‧‧ Width of the inclined area

S‧‧‧ cut-off line

1‧‧‧ glass substrate

2‧‧‧Polar plate (resin plate)

3‧‧‧shading board

Claims (3)

A method of cutting a resin sheet by cutting a resin sheet which is adhered to a resin sheet of a base substrate and relatively moving the laser beam while moving along a line to cut, and irradiating the resin sheet. The light intensity distribution of the laser beam is irradiated with a peak portion of a substantially constant intensity near the center of the optical axis of the beam and a tail portion that is gradually attenuated on the outer side thereof, from which the focus of the laser beam is The surface of the resin sheet is irradiated in a state of being defocused in the height direction, and the shielding member of the laser beam irradiated to the resin sheet is shielded so that the line to be cut is exposed and adjacent to the line to cut. In a mode configuration, the laser beam of the peak portion is irradiated to the line to cut, and the laser beam of the tail portion is blocked by the shielding member. The method for cutting a resin sheet according to the first aspect of the invention, wherein the laser beam is a CO ₂ laser. The method of cutting a resin sheet according to claim 1 or 2, wherein the resin sheet is adhered to a polarizing plate of a glass substrate of a liquid crystal display panel.