KR20220086812A - Fabrication Method for Ultra Thin Glass for Display Device - Google Patents

Abstract

The present invention relates to a method for manufacturing ultra-thin glass for a display, and more particularly, to an ultra-thin display that improves productivity by minimizing the physical force acting on the ultra-thin glass in the manufacturing process and minimizing surface damage that occurs to the ultra-thin glass in the manufacturing process It relates to a method for manufacturing glass.
The present invention relates to a method for manufacturing ultra-thin glass for a display used in a display device including a foldable display and a rollable display, wherein an ultra-thin glass original plate is cut into a rectangular shape of a certain size in consideration of the size of the display device by using a scriber cutting step; a separation film forming step of attaching a separator having a lower hardness than the ultra-thin glass and removable from the ultra-thin glass to at least one side of the ultra-thin glass cut in the cutting step; While applying an adhesive between the ultra-thin glasses, in the separation film forming step, the ultra-thin glass with a separator on one side is accurately laminated in several layers, and the separator is stacked between the ultra-thin glasses, or ultra-thin glass with a separator on both sides a lamination step of laminating ultra-thin glass with no separation film formed therebetween; an edge processing step of processing only the edge portion of the ultra-thin glass laminated to fit the shape of the display device; a side healing step of chemically etching the end of the laminated ultra-thin glass in a state where the edge processing step is completed; A separation step of separating each ultra-thin glass while removing the adhesive between the laminated ultra-thin glasses in a state where the side healing step is completed; a cleaning step of cleaning each ultra-thin glass separated in the separation step; a front healing step of chemically etching the entire surface of each of the ultra-thin glasses; and a chemical strengthening step of chemically strengthening each of the ultra-thin glasses using an ion exchange method. Including, wherein the separation membrane provides a method of manufacturing an ultra-thin glass for a display, characterized in that when the separation step is performed, the distance between the ultra-thin glasses is maintained so that they do not come into contact with each other.

Description

Fabrication Method for Ultra Thin Glass for Display Device

The present invention relates to a method for manufacturing ultra-thin glass for a display, and more particularly, to an ultra-thin display that improves productivity by minimizing the physical force acting on the ultra-thin glass in the manufacturing process and minimizing surface damage that occurs to the ultra-thin glass in the manufacturing process It relates to a method for manufacturing glass.

Commercially available methods for strengthening the surface by applying a compressive stress to the surface of glass can be divided into a physical strengthening method and a chemical strengthening method. The chemical strengthening method applies compressive stress to the surface of the glass by replacing sodium ions or lithium ions present in the glass with larger potassium ions. Recently, it has been applied to the cover glass of mobile devices such as mobile phones and tablets, and it is expected to be applied to ultra-thin glass applied to foldable displays or rollable displays.

The ultra-thin glass that can be folded or rolled, which can be applied to a foldable display or a rollable display, is less than 100 micrometers thick. In order to apply this thin glass to devices such as mobile phones, it is necessary to process the shape according to the device. However, if the work is done by a person, it must be handled very carefully, but there are cases where defects may occur due to the error of the operator during the manufacturing process.

On the other hand, when performing the above-mentioned shape processing, it is practically impossible to individually process the thin ultra-thin glass, so it is usually processed in a state of stacking about 10 sheets. At this time, an adhesive is applied between each ultra-thin glass to fix the ultra-thin glass. And, after the processing is completed, the adhesive is removed and each ultra-thin glass is separated. In the method of separating each ultra-thin glass, as shown in FIG. 1, in a state in which the adhesive (b) is melted, the ultra-thin glass (a) is separated by sliding it one by one in the direction of the arrow, and this separation is performed manually or It is carried out using dedicated automated equipment. At this time, either the end of the ultra-thin glass (a) (refer to FIG. 2a) or a front part (refer to FIG. 2b) of the ultra-thin glass (a) comes into contact with the ultra-thin glass disposed immediately below, at this time, there is a fine contact between the ultra-thin glasses As this occurs, fine scratches may occur on the surface. The scratches generated in this way cause defects in the ultra-thin glass in the long term.

The present invention has been devised to solve the problems of the background art, and the problem to be solved by the present invention is to minimize the risk of defects that may occur in the manufacturing process, thereby making the process efficient, improving productivity, and reducing the cost and time required for manufacturing. An object of the present invention is to provide a method for manufacturing ultra-thin glass for a display that can be reduced.

The present invention as a means for solving the above problems,

A method for manufacturing ultra-thin glass for a display used in a display device including a foldable display and a rollable display, the method comprising:

A cutting step of cutting the ultra-thin glass original plate into a rectangular shape of a certain size in consideration of the size of the display device using a scriber;

a separation film forming step of attaching a separator having a lower hardness than the ultra-thin glass and removable from the ultra-thin glass to at least one side of the ultra-thin glass cut in the cutting step;

While applying an adhesive between the ultra-thin glasses, in the separation film forming step, the ultra-thin glass with a separator on one side is accurately laminated in several layers, and the separator is stacked between the ultra-thin glasses, or ultra-thin glass with a separator on both sides a lamination step of laminating ultra-thin glass with no separation film formed therebetween;

an edge processing step of processing only the edge portion of the ultra-thin glass laminated to fit the shape of the display device;

a side healing step of chemically etching the end of the laminated ultra-thin glass in a state where the edge processing step is completed;

a separation step of separating each ultra-thin glass while removing the adhesive between the laminated ultra-thin glasses in a state where the side healing step is completed;

a cleaning step of cleaning each ultra-thin glass separated in the separation step;

a front healing step of chemically etching the entire surface of each of the ultra-thin glasses; and,

a chemical strengthening step of chemically strengthening each of the ultra-thin glasses using an ion exchange method; including,

The separation film provides a method of manufacturing ultra-thin glass for a display, characterized in that when the separation step is performed, the distance between the ultra-thin glasses is maintained so that they do not come into contact with each other.

The laminating step compares the position of the ultra-thin glass initially placed using a camera and the position of each ultra-thin glass stacked thereon, and corrects the position if there is a difference, or uses an alignment jig so that the ultra-thin glass overlaps accurately. It is preferable to do

The separation membrane is preferably formed by printing.

It is more preferable that the separator is attached by any one of screen printing, inkjet printing, offset printing, and transfer printing.

The separation membrane is preferably in the form of a band arranged at regular intervals.

The separator may be formed in a grid shape.

The separation membrane may have a predetermined shape and may be disposed at regular intervals.

The separation membrane may have an irregular shape.

The separation film may be formed on the whole of the cut ultra-thin glass.

The separator may be formed on the entirety of the cut ultra-thin glass except for some of the four corners.

The separator may be formed on the entire surface of the cut ultra-thin glass except for a portion of the four corners.

In the washing step, it is preferable to apply heat to the washing water to remove the separation film by the difference in thermal expansion coefficient between the ink and the ultra-thin glass or the expansion of microbubbles present in the ink.

In the washing step, the separation membrane may be removed by the expansion of the separation membrane by contacting the separation membrane with an organic solvent containing alcohol or acetone.

The full healing step is,

Any one of a first front healing step of chemically etching the entire surface of each ultra-thin glass on which the cleaning step is completed, and a second front healing step of chemically etching the entire surface of each ultra-thin glass in a state where the chemical strengthening step is completed, or It is preferable to consist of a combination of the two.

According to the present invention, by minimizing the physical force acting on the ultra-thin glass in the manufacture of ultra-thin glass, the risk of defects that may occur in the manufacturing process is minimized, thereby making the process efficient, improving productivity, and reducing the cost and time required for manufacturing. It relates to a method for manufacturing ultra-thin glass for use.

1 is a view for explaining the separation of the laminated ultra-thin glass.
2A and 2B are views for explaining damage to the surface of the ultra-thin glass in the process of separating the ultra-thin glass in the manner shown in FIG. 1;
Figure 3 is a view for explaining the cutting step of cutting the ultra-thin glass original plate into each ultra-thin glass.
4 is a view for explaining the cutting of the ultra-thin glass by a scriber.
5A is an enlarged cross-sectional view of ultra-thin glass cut by a scriber;
Figure 5b is an enlarged photograph of the cut surface of the ultra-thin glass cut using a dicing saw.
6A and 6B are views for explaining a lamination step;
7 is a view for explaining the edge processing step.
8 is a view for explaining the result of side healing.
9A to 9H are views showing various embodiments of the form of a separator.

Hereinafter, specific content for carrying out the present invention will be provided by describing one preferred embodiment of the present invention with reference to the drawings.

Figure 3 is a view for explaining the cutting step of cutting the ultra-thin glass original plate into each ultra-thin glass, Figure 4 is a view for explaining the cutting of the ultra-thin glass by the scriber, Figure 5a is the ultra-thin glass cut by the scriber An enlarged photograph of the cut surface of, FIG. 5B is an enlarged photograph of the cut surface of the ultra-thin glass cut using a dicing saw, FIGS. 6A and 6B are views for explaining the lamination step, FIG. 7 is a view for explaining the edge processing step, FIG. 8 is a view for explaining the result of side healing, and FIGS. 9A to 9H are views showing various embodiments of the form of a separator.

The method of manufacturing ultra-thin glass for a display according to this embodiment is a cutting step, a separator forming step, a lamination step, a corner processing step, a side healing step, a separation step, a cleaning step, a first front healing step, a chemical strengthening step, a second front healing step It consists of steps.

The cutting step is a step of cutting the ultra-thin glass original plate 1 into a rectangular shape of a certain size in consideration of the size of the display device using a scriber as shown in FIG. 6 .

Cutting the ultra-thin glass original plate 1 using a scriber is to cut the ultra-thin glass by applying a physical force after forming a fine groove 15 on the surface of the ultra-thin glass original plate 1 as shown in FIG. 4 . The thickness D of the ultra-thin glass shown in FIG. 5 is 100 micrometers or less, and the depth d of the grooves 15 is less than 10 micrometers. In the drawings, the depth d of the groove 15 is relatively deep, which is shown ignoring the proportions for convenience of description.

There are two advantages to using a scriber to cut an ultra-thin glass original.

Physical contact is reduced compared to the case of cutting using a dicing saw or a CNC cutter equipped with a cutting wheel as in the prior art. In order to cut using a dicing saw or CNC cutter, the entire cross section is in physical contact with the dicing saw. physical contact is reduced. As described above, the ultra-thin glass 10 is a very thin glass of 100 micrometers or less, but when it comes into physical contact, stress concentration is generated in a part of the glass during the cutting process and there is room for damage. There is a possibility that damage may occur to the blade, so it is necessary to minimize physical contact during the cutting process, which can be implemented by a scriber.

Second, when the ultra-thin glass 10 is cut by a scriber, it is possible to minimize the occurrence of fine chipping on the cut surface. 5A is a cross-sectional enlarged photograph of the ultra-thin glass cut by a scriber, and FIG. 5B is an enlarged cross-sectional photograph of the ultra-thin glass 10 cut by a conventional dicing saw. The fine chipping, which appears black in the photograph of FIG. 5B , is hardly visible in the cross section cut by the scriber. It can be said that this shows the advantage of cutting by a scriber well.

The separation film forming step is made of a material having a hardness lower than that of the ultra-thin glass on at least one side (on one side or both sides) of the ultra-thin glass 10, and attaching a separator 20 that can be separated from the ultra-thin glass 10 is a step to

The separation film 20 serves to prevent the ultra-thin glasses from coming into contact with each other during separation by maintaining a distance between the stacked ultra-thin glasses when performing the separation step.

Before and after the separation membrane forming step and the cutting step, cutting may be performed in a state in which the separation membrane is attached first, or the separation membrane may be attached after cutting.

In the separation film forming step, the separation film 20 attached to the ultra-thin glass 10 may be attached by printing, and may be attached by screen printing or inkjet printing among printing techniques. In this case, the ink used may be composed of a solvent, an initiator, a pigment or dye, a curing agent, an additive, and the like. When the separator 20 is attached by printing, the ink attached to the surface of the ultra-thin glass 10 becomes the separator 20 .

The shape of the separation membrane 20 may be manufactured in various ways. What is important is that when the ultra-thin glass 20 is separated after the lamination step, the ultra-thin glasses may have a shape in which they may not physically contact by maintaining a distance between the ultra-thin glasses.

Examples of various types of the separator 20 are shown in FIGS. 9A to 9H . The part with hatched dots in the drawing is the separator. As the separator 20, as shown in Fig. 9a, a band shape arranged at regular intervals, a grid shape as shown in Fig. 9b or 9c, and a regular shape as shown in Fig. 9d are regular intervals as shown in Fig. 9a. Arranged form (a circular shape is shown as a regular shape in FIG. 9d, but this is only an example, and any shape such as a triangle, square, or rectangle may be used), a form in which an irregular shape is irregularly arranged as shown in FIG. 9e, FIG. 9f It may be arranged in the form of being disposed on the front side as shown in Fig. 9g, arranged on the entire surface except for some of the four corners as shown in Fig. 9g, and in the form of a band formed on the edge of the ultra-thin glass as shown in Fig. 9h. have. The irregular shape shown in FIG. 9E is exemplary, and various types of patterns not shown in the figure may be attached to the surface of the ultra-thin glass 10 .

The lamination step is a step in which the thin glass 10 on which the separator 20 is formed in the separator formation step is stacked so that the thin glass 10 exactly overlaps.

There are two embodiments of a method of laminating the ultra-thin glass 10, and each embodiment is as follows. First, in the first embodiment, as shown in FIG. 6A , the ultra-thin glass 10 having the separator 20 formed on one side is stacked in several layers, and the separator 20 is stacked to be positioned between the ultra-thin glasses. In the second embodiment, as shown in FIG. 6B , the ultra-thin glass 10 on which the separation film is not formed is disposed and stacked between the ultra-thin glasses 10 having the separator 20 formed on both sides thereof.

When laminating the ultra-thin glass 10 in the lamination step, the adhesive 30 is applied between the ultra-thin glasses 10 . The laminated ultra-thin glasses 10 are fixed by the adhesive 30 . In general, about 10 ultra-thin glasses 10 are laminated, and protective glass may be laminated on the bottom and top. contact can be prevented. For the convenience of the city, the protective glass is excluded from the illustration, and only five ultra-thin glass 10 stacked are shown.

The reason why the ultra-thin glass 10 is accurately overlapped is to accurately process the edges in the edge processing step to be described later. In the case where there is a difference compared with the position of the ultra-thin glass 10 photographed initially while continuously photographing the position of the ultra-thin glass 10 that becomes may be made, and the ultra-thin glass 10 may be accurately overlapped using an alignment jig.

As the adhesive, a thermal adhesive cured by heat or an ultraviolet adhesive cured by ultraviolet rays may be used.

The edge processing step is a step of processing only the edge 11 of the ultra-thin glass 10 stacked according to the shape of the display device as shown in FIG. 7 . The edge 11 processing of the ultra-thin glass 10 is made by a CNC or grinder including a chamfering tool.

When processing only the edge 11, physical contact is reduced compared to the case of contacting the chamfering tool on the entire end. Since the effect of reducing the physical contact has already been described in the section describing the cutting step, further description will be omitted.

The reason that only the edge 11 can be processed in this embodiment is because it is possible to minimize chipping that occurs in the cross section by cutting using a scriber in the cutting step. Conventionally, the entire cross section was machined by CNC or a grinder for the purpose of removing chipping generated in the cross section. In this embodiment, since it is not necessary to remove the chipping of the cross section, only the edge 11 can be machined.

The process of removing chipping by contacting the entire section with a chamfering tool is very difficult to design process conditions. The chamfering tool comes into contact with the end of the ultra-thin glass 10 while rotating. If the chamfering tool does not properly adjust the pressure between the ultra-thin glass 10 and the rotation speed of the chamfering tool, damage to the ultra-thin glass 10 may occur. . It is necessary to design the process conditions through various trial and error processes, which takes a lot of time.

In addition, it takes a lot of time to process the entire surface. Under one condition designed by the inventor of the present invention, it may take 10 minutes or more to process the entire cross-section of the ultra-thin glass 10 .

When only the edge 11 is processed, the effect generated by reducing the physical contact as described above can also be expected. When used in a foldable display, the most stress is applied to the folded portion. If physical contact between the folded portion is reduced in the manufacturing process of ultra-thin glass, an increase in the lifespan of the ultra-thin glass can be expected.

In addition to the effect of reducing physical contact, it may take relatively little time to design process conditions, and relatively little time to process.

The side healing step is a step of chemically etching the end portion 12 of the ultra-thin glass 10 after the edge processing step is completed. Residual stress at the end of the ultra-thin glass 10 is relieved by chemical treatment, and the end 12 is machined in the shape shown in FIG. 8 .

The separation step is a step of separating the laminated ultra-thin glass 10 in a state where the side healing step is completed into each ultra-thin glass 10 . In a state in which the adhesive 30 is fluidized by heat or UV, as shown in FIG. 1 , separate each ultra-thin glass 10 by a sliding method or by lifting all or part of the ultra-thin glass (not shown) do.

The separation step is a very delicate operation. Since the ultra-thin glass 10 is literally very thin glass, damage can occur even with a small amount of force. It is common.

In the present invention, in the process of separating the laminated ultra-thin glass into each ultra-thin glass 10, the separation film 20 maintains a distance between the ultra-thin glasses 10, so that contact occurs between the separated ultra-thin glasses 10 Therefore, the effect of fundamentally eliminating the occurrence of front scratches, which is a problem of the prior art, can be expected.

The cleaning step is a step of cleaning while removing the separation membrane 20 attached to each ultra-thin glass 10 separated in the separation step. In this embodiment, the ink as the separator 20 used is removed by putting the ultra-thin glass 10 to which the separator 20 is attached in hot water, hot water, or high-temperature alkaline water, and the thermal expansion coefficient of the separator 20 and the ultra-thin glass 10 Separation occurs due to this difference or due to expansion of microbubbles present in the separation membrane 20 . When an organic solvent such as alcohol or acetone is used as the cleaning solution, the ink, which is the separator 20, swells and peels off.

The first front healing step is a step of chemically etching the entire surface of each ultra-thin glass 10 on which the cleaning step is completed. By the first front healing step, the illuminance of the front surface of the ultra-thin glass 10 is improved, and the effect of mitigating the micro-grooves occurs.

The chemical strengthening step is a step of chemically strengthening each ultra-thin glass on which the first front healing step has been completed through an ion exchange method. Chemical strengthening is achieved by immersing the glass in an alkali salt (mainly liquid KNO ₃ ) that exists in a molten state at a high temperature (temperature around 400° C.) for a certain period of time, and K ⁺ ions, which are alkali ions in a molten state, are formed on the surface of the glass. An immersion method in which ion exchange occurs with ions, Na ⁺ ions, and a method in which ion exchange is achieved by heating in a state in which an alkali salt in slurry or paste state is applied so that it can adhere well to the surface of the glass, or an alkali salt There is a non-immersion method in which alkali ions in a liquid or semi-liquid state are formed on the glass surface by melting or semi-melting, and alkali ions in an ion-exchangeable state are ion-exchanged with alkali ions inside the glass. It can be chemically strengthened.

The second front healing step is a step of chemically etching the entire surface of each ultra-thin glass in a state in which the chemical strengthening step has been completed, and may be performed in the same manner as the first front healing step described above.

When the second front healing step is completed, the method for manufacturing ultra-thin glass for a display according to the present embodiment is completed.

In the above, an embodiment in which both the first and second full healing steps were described has been described, but only the first full healing step performed after the cleaning step or only the second full healing step performed after chemical strengthening is carried out Even if it is, it should be regarded as belonging to the scope of the present invention.

In the above, specific content for carrying out the present invention has been provided by describing one preferred embodiment of the present invention, but the technical spirit of the present invention is not limited to the described embodiment, and various forms within the technical spirit of the present invention are provided. It can be embodied as a method of manufacturing ultra-thin glass for display.

1: Ultra-thin glass original plate 10: Ultra-thin glass
11: Ultra-thin glass edge 12: Ultra-thin glass side
15: groove 20: separator
30: adhesive

Claims (14)

A method for manufacturing ultra-thin glass for a display used in a display device including a foldable display and a rollable display, the method comprising:
A cutting step of cutting the ultra-thin glass original plate into a rectangular shape of a certain size in consideration of the size of the display device using a scriber;
a separation film forming step of attaching a separator having a lower hardness than the ultra-thin glass and removable from the ultra-thin glass to at least one side of the ultra-thin glass cut in the cutting step;
While applying an adhesive between the ultra-thin glasses, in the separation film forming step, the ultra-thin glass with a separator on one side is accurately laminated in several layers, and the separator is stacked between the ultra-thin glasses, or ultra-thin glass with a separator on both sides a lamination step of laminating ultra-thin glass with no separation film formed therebetween;
an edge processing step of processing only the edge portion of the ultra-thin glass laminated to fit the shape of the display device;
a side healing step of chemically etching the end of the laminated ultra-thin glass in a state where the edge processing step is completed;
A separation step of separating each ultra-thin glass while removing the adhesive between the laminated ultra-thin glasses in a state where the side healing step is completed;
a cleaning step of cleaning each ultra-thin glass separated in the separation step;
a front healing step of chemically etching the entire surface of each of the ultra-thin glasses; and,
a chemical strengthening step of chemically strengthening each of the ultra-thin glasses using an ion exchange method; including,
The method for manufacturing ultra-thin glass for a display, characterized in that the separation membrane is configured not to contact each other by maintaining a distance between the ultra-thin glasses when performing the separation step.
According to claim 1,
The laminating step compares the position of the ultra-thin glass initially placed using a camera with the position of each ultra-thin glass stacked thereon, and corrects the position if there is a difference, or uses an alignment jig so that the ultra-thin glass overlaps accurately. A method for manufacturing ultra-thin glass for a display, characterized in that
According to claim 1,
The separator is a method of manufacturing ultra-thin glass for a display, characterized in that it is attached by printing.
4. The method of claim 3,
The separator is an ultra-thin glass manufacturing method for a display, characterized in that it is attached by any one of screen printing, inkjet printing, offset printing, and transfer printing.
According to claim 1,
The separator is a method for manufacturing ultra-thin glass for a display, characterized in that the strip is arranged at regular intervals.
According to claim 1,
The separator is a method of manufacturing an ultra-thin glass for a display, characterized in that the grid shape.
According to claim 1,
The separator is a method of manufacturing ultra-thin glass for a display, characterized in that the regular shape is arranged at regular intervals.
According to claim 1,
The separator is an ultra-thin glass manufacturing method for a display, characterized in that irregularly arranged in an irregular shape. According to claim 1,
The separator is a method of manufacturing ultra-thin glass for a display, characterized in that formed on the entire surface of the cut ultra-thin glass.
According to claim 1,
The method for manufacturing ultra-thin glass for a display, characterized in that the separator is formed on the entire surface except for a portion of the four corners of the cut ultra-thin glass.
According to claim 1,
The method for manufacturing ultra-thin glass for a display, characterized in that the separator is formed on the entire surface except for the edge of the cut ultra-thin glass.
3. The method of claim 2,
In the washing step, heat is applied to the washing water to remove the separator by a difference in thermal expansion coefficient between the ink and the ultra-thin glass or the expansion of microbubbles present in the ink.
3. The method of claim 2,
In the washing step, the separation membrane is contacted with an organic solvent containing alcohol or acetone to remove the separation membrane by expansion of the separation membrane.
According to claim 1,
The full healing step is
Any one of a first front healing step of chemically etching the entire surface of each ultra-thin glass on which the cleaning step is completed, and a second front healing step of chemically etching the entire surface of each ultra-thin glass in a state in which the chemical strengthening step is completed, or A method for manufacturing ultra-thin glass, characterized in that it consists of a combination of the two.

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