KR20060034908A - Polishing method of glass substrate for ODL, and glass substrate for ODL produced using same - Google Patents

Abstract

The present invention relates to a method for polishing an organic EL glass substrate, and to a glass substrate for OID produced using the same, comprising: a lower plate attached to an upper surface and rotating in a predetermined direction; and a lower plate in close contact with the lower plate. A method for polishing a glass substrate for organic EL using a glass polishing apparatus having an upper surface plate that is repeatedly rotated at a predetermined angle on a predetermined angle on a surface and a polishing liquid supply portion for supplying a polishing liquid on the lower surface plate, the method comprising: a ceria-based abrasive; First polishing the glass substrate with a polishing liquid; And secondary polishing the first polished glass substrate with a polishing liquid including a silica-based abrasive. Thereby, a method for polishing an organic EL glass substrate capable of improving the flatness and roughness of a glass substrate, and an OLD glass substrate produced using the same are provided.

Glass substrate for organic EL, polishing method

Description

Polishing method of glass substrate for organic EL, and glass substrate for ODL produced using same {Method of Polishing Glass for OLED and Glass for OLED manufactured using the same}

1 is a perspective view showing a polishing apparatus used in the polishing method of an organic EL glass substrate according to the present invention,

2 is a flow chart showing a method of polishing a glass substrate for organic EL according to the present invention;

3 is a graph showing the polishing conditions of the primary polishing in the polishing method of the organic EL glass substrate according to the present invention,

4 is a surface photograph of a glass substrate photographed by an optical microscope of the surface of the glass substrate polished by the secondary polishing step of the polishing method according to the present invention;

5 is a graph showing the polishing conditions of the secondary polishing in the polishing method of the glass substrate for organic EL according to the present invention;

6 is a surface photograph of a glass substrate photographed by an optical microscope of the surface of the glass substrate polished by the secondary polishing step of the polishing method according to the present invention.

♣ Explanation of symbols for the main parts of the drawing

                     1: body 2: bottom plate

                     3: top plate 4: cylinder

                     5: turning drive part 6: polishing liquid supply part

                    11: fence 21: polishing pad

                    51: support arm 52: pivot

                    61: upper supply conduit 62: estuary salary conduit

The present invention relates to a method for polishing a glass substrate for organic EL, and more particularly, to a polishing method capable of realizing low roughness by polishing a glass substrate for organic EL.

In general, display devices using OLEDs can be driven at 15 volts or less, have high luminous efficiency, low power consumption, and reduce the production cost to less than half of LCD because no TFT-LCD thin film transistor process is required. Because of its self-luminous type, its viewing angle is wider than other displays, and it is getting attention as a next generation display device because of its thinness, lightness, and fast response speed. The display device using the organic EL has a structure in which an ITO thin film is coated on a glass substrate and an organic light emitting layer is formed on the ITO thin film.

Therefore, the roughness and flatness of the glass substrate used in the organic EL have a great influence on the performance of the display device using the organic EL. Such a glass substrate is first subjected to polishing in order to be used in the manufacture of the organic EL.

In the conventional method for polishing a glass substrate, the glass substrate is polished by the same abrasive and the polishing pad using a polishing apparatus, and then introduced into an organic EL manufacturing process such as ITO thin film coating.

However, according to the prior art described above, since the polishing and the flatness of the glass substrate can be realized by one polishing, there is a problem in that the roughness and the flatness cannot be simultaneously implemented at low values.

Therefore, when the ITO thin film is coated on the glass substrate, which is a subsequent process, spikes are generated, thereby lowering luminance and power efficiency in driving the organic EL, and may cause device defects.

Accordingly, an object of the present invention is to solve such a conventional problem, and to provide a method for polishing an organic EL glass substrate capable of polishing the organic EL glass substrate with low roughness.

In addition, the present invention provides a method for polishing a glass substrate for organic EL which can reduce defects in manufacturing an organic EL using a glass substrate by polishing the glass substrate with low roughness.

In addition, the present invention provides a method of polishing a glass substrate for organic EL, which can increase the power efficiency and brightness of the organic EL using the glass substrate by polishing a low roughness glass substrate.

According to the present invention, a polishing pad is attached to the upper surface and the upper surface rotates in a predetermined direction, the upper surface is in close contact with the lower surface plate and repeatedly rotated left and right at a predetermined angle on the lower surface plate, the polishing on the lower surface plate CLAIMS 1. A method for polishing a glass substrate for organic EL using a glass polishing apparatus having a polishing liquid supply portion for supplying a liquid, the method comprising: first polishing a glass substrate with a polishing liquid containing a ceria-based abrasive; The first polished glass substrate is achieved by a method of polishing a glass substrate for organic EL, comprising the second step of polishing the glass substrate with a polishing liquid containing a silica-based abrasive.

On the other hand, when polishing is performed in the first polishing step and the second polishing step, the pressure in the upper plate is changed downward, and the rotational speed of the lower plate and the rotation speed of the upper plate are shifted so that the polishing proceeds. It is preferable to improve the flatness and surface roughness of the glass substrate.

The ceria-based abrasive is cerium oxide, and the silica-based abrasive is colloidal silica, which is preferable because it can polish the glass substrate for organic EL with low roughness.

In addition, in the first polishing step, the polishing pad may include a foaming agent and cerium oxide, and in the second polishing step, the polishing pad may be foamed urethane, so that the glass substrate for organic EL may be polished with low roughness.

The glass substrate produced by the method is characterized in that the surface roughness is 30 ~ 70 Å and the flatness is 300 Å to 500 Å.

Hereinafter, a method of polishing an organic EL glass substrate according to the present invention will be described in detail with reference to the accompanying drawings.

Before describing the polishing method of the glass substrate for organic EL according to the present invention, the polishing apparatus used in the polishing method of the glass substrate for organic EL is first described.

1 is a perspective view showing a polishing apparatus used in the method for polishing a glass substrate for organic EL according to the present invention. The polishing apparatus includes a main body 1, a lower plate 2 provided on the upper surface of the main body 1, a rotation driving unit (not shown) for rotating the lower plate 2, and an upper portion of the lower plate 2. The upper plate 3 to be installed, the cylinder 4 to move the upper plate 3 up and down in combination with the upper plate 3, and the swing to engage the cylinder 4 to drive the upper plate 3 to rotate. The driving part 5 and the polishing liquid supply part 6 which supplies a polishing liquid to the lower plate 2 are included.

The lower surface plate 2 is installed in the main body 1, and a scattering prevention fence 11 is installed to prevent scattering of the polishing liquid supplied from the polishing liquid supply unit 6 along the outer circumference of the lower surface plate 2. On one side of the shatterproof fence 11, a polishing liquid discharge hole (not shown) for collecting the polishing liquid is formed. On the other hand, the polishing pad 21 is provided on the upper surface of the lower plate 2.

The top plate 3 is provided with a polishing holder (not shown) to which a glass substrate for organic EL to be polished is attached on the bottom surface. The polishing holder is provided with a plurality of mounting holes to correspond to the outer shape of the glass substrate for organic EL.

The cylinder 4 is engaged with the upper surface of the upper plate 3 to move the upper plate 3 up and down, and the upper plate 3 is pressed downward in contact with the polishing pad 21.

The pivot drive part 5 includes a support arm 51 supporting the upper plate 3 in the horizontal direction with respect to the lower plate 2, and one end of the support arm 51 so as to pivot the support arm 51 from side to side. It includes a swing shaft 52 and a swing drive motor (not shown) to operate the swing shaft 52 to the left and right. Here, the rotational speed of the lower platen 2 and the pressurization and the rotational speed of the upper platen 3 may be controlled differently according to the progress time when polishing is performed.

The polishing liquid supply unit 6 is arranged to supply the polishing liquid to the center and the outer side of the lower plate 2. That is, the polishing liquid supply part 6 is branched into the upper supply conduit 61 and the lower supply conduit 62 at a predetermined position. The upper supply conduit 61 is attached to a predetermined portion of the support arm 51 to supply the polishing liquid to the outer portion of the lower plate 2, and the lower supply conduit 62 communicates with the central portion of the lower plate 2. Then, the polishing liquid is supplied to the center portion of the lower plate 2.

By such a polishing apparatus, the glass substrate for organic EL to be polished is attached to the top plate 3 by a polishing holder provided on the bottom surface of the top plate 3, and the top plate 3 is moved left and right on the bottom plate 2. While repeating the swing operation, it rotates in conjunction with the rotation of the lower plate (2). As a result, the organic EL glass substrate attached to the lower surface of the upper plate 3 is polished by the polishing pad 21 attached to the upper surface of the lower plate 2 and the polishing liquid supplied by the polishing liquid supply unit 6. .

Next, the polishing method of the glass substrate for organic EL using the above-mentioned polishing apparatus is demonstrated. 2 is a flowchart illustrating a method of polishing a glass substrate for organic EL according to the present invention. As shown in the figure, the polishing method of the organic EL glass substrate, the first step of first polishing the glass substrate using a polishing apparatus having a polishing liquid containing a ceria-based abrasive (S1), and first polishing Secondary polishing of the glass substrate with a polishing apparatus including a polishing liquid containing a silica-based abrasive (S2).

As the polishing pad 21 attached to the lower plate 2 in the first polishing step S1, a polyurethane polishing pad in which a polyol, isocyanate, a silicon foam stabilizer, a catalyst, etc. is mixed with a blowing agent and cerium oxide is used. . The abrasive included in the polishing liquid includes cerium oxide-based abrasives such as lanthanum oxide, praseodymium oxide, and neodymium oxide, and is composed of DI water. Here, the weight ratio of cerium oxide, lanthanum oxide, praseodymium oxide, and neodymium oxide is configured as shown in Table 1 below. In addition, these particle sizes are used within the range of 100 nm to 150 nm.

Table 1

Configuration Cerium oxide Lanthanum oxide Praseodymium Oxide Neodymium oxide Weight ratio (%) 50-65 30-40 3-8 1-15

The first polishing step (S1) of the glass substrate for organic EL is performed using the polishing pad 21 having the above-described conditions and the polishing liquid. The polishing conditions in the primary polishing step S1 will be described. 3 is a graph showing the polishing conditions of in the first polishing step (S1) of the polishing method of the glass substrate for organic EL according to the present invention. As shown in the figure, in the first polishing step (S1) using the above-described polishing apparatus, as the polishing time elapses, pressurizing and turning speed of the upper plate 3 and the rotational speed of the lower plate 2 are divided into sections. Proceed with polishing while changing very much.

First, in the first section (section 0 to A), the pressing force of the upper plate 3 is small, and the polishing proceeds for a predetermined time in a state where the rotation speed of the lower plate 2 and the turning speed of the upper plate are slow. Subsequently, in the second section A to B, polishing is performed for a predetermined time in a state where the pressing force of the upper plate 3, the rotational speed of the lower plate 2, and the turning speed of the upper plate 3 are at their highest. .

In the third section (B to C), only the pressing force of the upper table 3 is maintained in the first section (0 to A section) while maintaining the rotational speed of the lower table 2 and the turning speed of the upper table 3 as it is. Polishing is carried out for a predetermined time while reducing the pressure to a pressure lower than).

In the fourth section C to D, the pressing force of the upper plate 3 is further reduced, and the rotational speed of the lower plate 2 is reduced to the same speed as the rotational speed of the first section (section 0 to A). Further, the turning speed of the upper plate 3 is reduced to a lower speed than the turning speed of the initial section (section 0 to A), and the polishing is performed for a predetermined time.

In the fifth section (D to E), while the rotation speed of the upper plate 3 is maintained as it is, the pressing force of the upper plate 3 and the rotational speed of the lower plate 2 are further reduced, and then polishing is performed for a predetermined time. Proceed and finish polishing.

On the other hand, while polishing is in progress, the polishing liquid is supplied through the upper supply conduit 61 and the lower supply conduit 62 of the polishing liquid supply part 6. At this time, the amount of the polishing liquid is maintained such that the amount supplied through the upper supply conduit 61 is greater than the amount supplied through the lower supply conduit 62.

In this way, the first polishing (S1) is carried out to lower the flatness of the organic EL glass substrate by the action of the abrasive and the polishing pad 21. That is, in the primary polishing step S1, the purpose of polishing is to improve flatness rather than improving roughness of the glass substrate.

Subsequently, the secondary polishing step S2 of the glass substrate for organic EL is performed. Secondary polishing step (S2), unlike the first polishing (S1), the polishing pad 21 uses a foam type urethane. Secondary polishing step (S2) is a polishing to improve the surface roughness of the glass substrate having a flatness improved by the first polishing step (S1), so use a foam type polyurethane foam. As the polishing liquid, a mixture of liquid colloidal silica and DI water is used. In the above-described first polishing step (S2), a solid ceria-based abrasive was mixed with DI water in order to lower the flatness of the glass substrate. Use Looking at the distribution of the polishing liquid, DI water and other additives are mixed so that the silica (SiO ₂ ) has a weight ratio of 35% to 50%. At this time, the particle size of the silica is to maintain 70nm ~ 100nm or less.

4 is a surface photograph of a glass substrate photographed by an optical microscope of the surface of the glass substrate polished by the primary polishing step of the polishing method according to the present invention. As shown in the figure, the surface flatness of the glass substrate polished by the above-described primary polishing step (S1) can maintain 300 ~ 500 Å.

The secondary polishing step S2 of the glass substrate for organic EL is performed using the polishing pad 21 and the polishing liquid having the above conditions. The polishing conditions in the secondary polishing step S2 will be described. 5 is a graph showing the polishing conditions in the secondary polishing step (S2) of the polishing method of the glass substrate for organic EL according to the present invention. As shown in the figure, in the secondary polishing step S2, similarly to the primary polishing step S1, the pressing and turning speed of the upper plate 3 and the rotation of the lower plate 2 using the polishing device described above. As the polishing time elapses, the polishing is carried out while varying in each section.

In the first section (section 0 to A), polishing is performed for a predetermined time while the pressing force of the upper plate 3 is small, and the rotation speed of the lower plate 2 and the turning speed of the upper plate 3 are slow. Subsequently, in the second section A to B, polishing is performed for a predetermined time while the pressing force of the upper plate 3, the rotational speed of the lower plate 2, and the turning speed of the upper plate 3 are raised to the maximum.

In the third section (B ~ C section), the rotation speed of the lower platen 2 and the turning speed of the upper plate 3 are maintained as they are, and the pressing force of the upper plate 3 is lowered again to the same pressure as the original pressing force. Polishing is performed for a predetermined time.

In the fourth section C to D, the pressing force of the upper plate 3 is further reduced, and the rotational speed of the lower plate 2 is reduced to the same speed as the rotational speed of the first section (section 0 to A). In addition, the turning speed of the upper plate 3 is reduced to maintain a faster speed than the turning speed of the initial section (section 0 to A). That is, the turning speed of the upper plate 3 maintains the intermediate speed between the second section (section A and B) and the first section (section 0 through A). Polishing is performed for a predetermined time under the above conditions.

In the fifth section (sections D to E), the pressing force of the upper plate 3, the rotational speed of the lower plate 2, and the rotational speed of the upper plate 3 are reduced to finish polishing. At this time, the turning speed of the upper plate 3 is reduced to maintain a lower speed than the turning speed of the first section (section 0 ~ A).

On the other hand, in the secondary polishing step (S2), the pressing force of the upper surface plate 3 is maintained at a value smaller than the pressing force of the primary polishing step (S1). This is because the polishing amount in the secondary polishing step S2 is smaller than the polishing amount in the first polishing step S1, so that the desired roughness value cannot be achieved if the pressing force of the upper surface plate 3 is kept high. However, the rotational speed of the lower surface plate 2 or the rotational speed of the upper surface plate 3 is maintained similar to the speed in the primary polishing step S1.

  Further, while polishing is in progress, the polishing liquid is supplied in an amount smaller than the polishing liquid supply in the primary polishing step S1. Since the second polishing step (S2) improves the surface roughness of the glass substrate, the polishing liquid is supplied less than the first polishing because the amount of polishing on the glass substrate surface is smaller than that of the first polishing step (S1). The supply amount of the polishing liquid in the conduit 61 and the lower supply conduit 62 is maintained such that the amount supplied through the upper supply conduit 61 is greater than the amount supplied through the lower supply conduit 62.

6 is a surface photograph of a glass substrate photographed by an optical microscope of the surface of the glass substrate polished by the secondary polishing step of the polishing method according to the present invention. As shown in the figure, the surface roughness of the glass substrate polished by the secondary polishing step (S2) may be implemented with an Rp-v value of 30 kPa to 70 kPa.

By the polishing method according to the above-described steps, the glass substrate for organic EL can be polished to low values of flatness and surface roughness.

As described above, according to the present invention, a method for polishing an organic EL glass substrate capable of polishing the organic EL glass substrate with low roughness is provided.

In addition, there is provided a method of polishing a glass substrate for organic EL which can reduce defects in manufacturing an organic EL using a glass substrate by polishing the glass substrate with low roughness.

In addition, by polishing a low roughness glass substrate, there is provided a method for polishing an organic EL glass substrate which can increase the power efficiency and brightness of the organic EL using the glass substrate.

Claims (7)

A lower surface plate attached to an upper surface of the polishing pad and rotating in a predetermined direction, an upper surface plate that is repeatedly rotated left and right at a predetermined angle on the lower surface surface while being in close contact with the lower surface plate and pressed downward, and a polishing liquid is placed on the lower surface surface. In the polishing method of the glass substrate for organic EL using the glass polishing apparatus which has a polishing liquid supply part to supply, Primary polishing the glass substrate with a polishing liquid containing a ceria-based abrasive; And polishing the first polished glass substrate with a polishing liquid containing a silica-based abrasive. The method of claim 1, When the polishing is carried out in the first polishing step and the second polishing step, the upper platen is transformed downward pressure, the rotational speed of the lower platen and the rotational speed of the upper plate is shifted to the organic polishing, characterized in that Polishing method of EL substrate. The method according to claim 1 or 2, The ceria-based abrasive is cerium oxide, and the silica-based abrasive is colloidal silica polishing method for a glass substrate for organic EL. The method of claim 3, And the polishing pad in the first polishing step comprises a blowing agent and cerium oxide. The method of claim 4, wherein In the second polishing step, the polishing pad is a polishing method of an organic EL glass substrate, characterized in that the foamed urethane. A glass substrate for OLED produced by using the polishing method according to claim 1. The method of claim 6, The glass substrate has a surface roughness of 30 Å to 70 Å and a flatness of 300 Å to 500 Å.

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