Patent Description:
An edge effect of a glass panel is a main factor in damage to the glass panel, and the damage in turn lowers the reliability of the glass panel. In particular, a flexible device including a thin glass panel requires superior edge quality for reliable bending performance. In such a flexible device, the removal of an edge defect is very important.

Edge finishing may be performed in order to improve the edge strength of a glass panel. From among such edge finishing technologies, a heat chamfering technology is known. Heat chamfering does not cause particles, and is a technology suitable for use with thin glass plates. In addition, heat chamfering may ensure superior edge strength and provide satisfactory bending performance.

<CIT> relates to a chamfering device. <CIT> relates to a fusion bonding and alignment fixture. <CIT> relates to a device and method for forming glass. <CIT> relates to a method for manufacturing an electro-optical device.

The present invention relates to a heat chamfering apparatus including: a support unit supporting a glass panel; and a heat chamfering unit heat- chamfering an edge of the glass panel by applying thermal shock thereto.

The support unit includes: a contact support portion supporting the glass panel while in contact with the glass panel and formed from a first material; and a base portion supporting the contact support portion and formed from a second material. The first material has lower thermal conductivity, a lower coefficient of thermal expansion, and lower hardness than the second material.

The first material may have a smaller change in temperature due to lower thermal conductivity and a smaller change in size at high temperature due to a smaller coefficient of thermal expansion while being more ductile due to lower hardness, compared to the second material.

In addition, the present invention relates to a heat chamfering method including: locating a glass panel on a support unit; and heat-chamfering an edge of the glass panel by applying thermal shock thereto. The support unit comprises: a contact support portion supporting the glass panel while in contact with the glass panel and formed from a first material; and a base portion supporting the contact support portion and formed from a second material. The first material has lower thermal conductivity, a lower coefficient of thermal expansion, and lower hardness than the second material.

The present disclosure may realize a reliable and accurate heat chamfering process.

Accordingly, it is possible to improve process efficiency and reduce process time.

The methods and apparatuses of the present disclosure have other features and advantages that will be apparent from or that are set forth in greater detail in the accompanying drawings, the disclosures of which are incorporated herein, and in the following Detailed Description, which together serve to explain certain principles of the present disclosure.

<FIG> is a view illustrating a method of heat-chamfering a glass panel according to an embodiment of the present disclosure.

An edge of a glass panel <NUM> is heat-chamfered by thermal shock applied thereto. Such thermal shock may be induced by the difference between the temperature of the edge of the glass panel <NUM> heated by a hot body <NUM> (i.e., a body heated to a high temperature) and the temperature of the remaining portion of the glass panel <NUM>. In some embodiments, the edge of the glass panel <NUM> may be peeled by moving the hot body <NUM> heated by a heater <NUM> along the edge of the glass panel <NUM> while allowing the hot body <NUM> to be in contact with the edge of the glass panel <NUM>. Pressure applied to the edge of the glass panel <NUM> by the hot body <NUM> during the heat chamfering may be constant. For the relative movement, the glass panel <NUM> may be moved as illustrated in <FIG> (where an arrow depicted in <FIG> indicates the direction of the movement of the glass panel), the hot body <NUM> may be moved or both the glass panel <NUM> and the hot body <NUM> may be moved.

The glass panel <NUM> according to the present disclosure may include panels formed from any glass material (e.g., borosilicate glass).

Although the main plane of the glass panel <NUM> may have an oblong shape, the glass panel <NUM> is not limited to a specific shape, such as a polygon, a circle, or an ellipse. In the present disclosure, the glass panel <NUM> may be a sheet having a thickness (e.g., the measurement in the Z-axis direction) smaller than either the transverse length (e.g., the measurement in the X-axis direction) or the longitudinal length (e.g., the measurement in the Y-axis direction) of the main plane. However, the present disclosure is not limited thereto, and the glass panel <NUM> may have a variety of shapes, such as a thick block.

For example, when the main plane of the glass panel <NUM> has an oblong cross-sectional shape and the main plane of the glass panel is an X-Y plane, the hot body <NUM> may perform chamfering by relatively moving in the X direction and the Y direction while in sequentially being in contact with four edges of the glass panel <NUM>. The relative movement speed may vary depending on the composition of the glass, the temperature conditions, or the shape of the glass panel <NUM> to be chamfered. In response to this chamfering, a strip 100a is peeled off from the edges of the glass panel <NUM>. In some embodiments, the hot body <NUM> may perform the chamfering while continuously coming into contact with the four edges without interruption. For example, when the four edges of the glass panel <NUM> are referred to as a first edge, a second edge, a third edge, and a fourth edge in the clockwise direction, the hot body <NUM> may chamfer all of the four edges of the glass panel <NUM> by relatively moving in the X-axis direction until reaching the corner between the first edge and the second edge while being in contact with the first edge, relatively moving in the Y-axis direction until reaching the corner between the second edge and the third edge while being in contact with the second edge, relatively moving in a direction opposing the X-axis direction until reaching the corner between the third edge and the fourth edge while being in contact with the third edge, and then, relatively moving in a direction opposing the Y-axis direction until reaching the corner between the fourth edge and the first edge while being in contact with the fourth edge.

Due to this chamfering, the thin strip 100a may be peeled off from the glass panel <NUM> without causing particles so as to remove defects from the edges of the glass panel <NUM> and increase the strength of the glass panel <NUM>.

In some embodiments, the glass panel <NUM> may perform the chamfering in a situation in which the glass panel <NUM> is fixedly located on the top surface of a support unit to be described later.

<FIG> is a view schematically illustrating a heat chamfering unit of a glass panel heat chamfering apparatus according to some embodiments of the present disclosure.

The heat chamfering apparatus includes the heat chamfering unit heat-chamfering an edge of a glass panel by applying thermal shock thereto.

The heat chamfering unit may include: the hot body <NUM> configured to peel the edge of the glass panel by applying thermal shock to the glass panel while being in contact with the edge of the glass panel; and the heater <NUM> heating the hot body.

In some embodiments, the hot body <NUM> may be a heating rod. In some embodiments, a contact area of the hot body <NUM> to be in contact with the glass panel <NUM> may have the shape of a cylinder. In some embodiments, the hot body <NUM> may be a metal rod. For example, the hot body <NUM> may be implemented using a metal rod formed from MoSi2. However, the hot body <NUM> according to the present disclosure is not limited thereto.

The hot body <NUM> may include a heated area and a contact area in the longitudinal direction thereof, in which the heated area may be heated by the heater <NUM>, and the contact area may be in contact with the glass panel <NUM>. In some embodiments, the cross-sectional area of the contact area (on the plane parallel to the main plane of the glass panel <NUM>) may be smaller than the cross-sectional area of the heated area. Heat applied to the heated area may be transferred to the contact area. The contact area may be located on one end of the hot body <NUM>. The other end of the hot body <NUM> may be held by a holder (not shown).

At a specific point in time, the hot body <NUM> may be in point contact or line contact with the glass panel <NUM> (e.g., the cylindrical portion of the hot body <NUM> may be in contact with the glass panel <NUM>) or may be in surface contact with the glass panel <NUM> (e.g., the hot body <NUM> having a heating surface of a predetermined area may be in contact with the glass panel <NUM>). In some embodiments, the line in the line contact and the surface in the surface contact may be parallel to a side surface (i.e., thickness surface) of the glass panel <NUM>. However, the present disclosure is not limited thereto and the line or surface in contact may be at a predetermined angle to the side surface of the glass panel <NUM>.

The heater <NUM> may heat the hot body <NUM> by high-frequency induction heating. The heater <NUM> may heat the hot body <NUM> while surrounding the hot body <NUM>. In some embodiments, the heater <NUM> may be an induction coil. The hot body <NUM> may extend through the center of the induction coil. In some embodiments, the induction coil may be implemented using a copper (Cu) coil. In addition, the outer surface of the induction coil may be coated with a ceramic material for electrical safety. In some embodiments, cooling water may flow within the induction coil. In some embodiments, the induction coil may heat the hot body <NUM> to a temperature in a range from about <NUM> to about <NUM> by transmitting power to the hot body <NUM>.

<FIG> is a view schematically illustrating a support unit of the heat chamfering apparatus according to some embodiments of the present disclosure, <FIG> is a plan view schematically illustrating the support unit of the heat chamfering apparatus illustrated in <FIG>, <FIG> is a view schematically illustrating the base portion of the support unit illustrated in <FIG>, <FIG> is a view schematically illustrating the contact support portion of the support unit illustrated in <FIG>, <FIG> is a view illustrating the support unit and an alignment unit of the heat chamfering apparatus according to some embodiments of the present disclosure, and <FIG> is a plan view illustrating the support unit and the alignment unit of the heat chamfering apparatus illustrated in <FIG>.

The heat chamfering apparatus includes a support unit supporting the glass panel <NUM>. The support unit includes a contact support portion <NUM> supporting the glass panel <NUM> while being in contact with the glass panel <NUM> and a base portion <NUM> supporting the contact support portion <NUM>. The base portion <NUM> may be spaced apart from the glass panel <NUM> without contact therewith.

The contact support portion <NUM> may be located closer to the heater <NUM> than the base portion <NUM> is. Referring to <FIG> and <FIG>, the heater <NUM> may be located above the glass panel <NUM>, the contact support portion <NUM> may be located below the glass panel <NUM>, and the base portion <NUM> may be located below the contact support portion <NUM>.

The contact support portion <NUM> is a portion that serves to support the glass panel <NUM> by direct contact with the glass panel <NUM> during a process so that the process is performed while the glass panel <NUM> is being in contact with the hot body <NUM> below a predetermined pressure. The contact support portion <NUM> is formed from a first material that may have little temperature change due to the low thermal conductivity thereof, have little size change due to the low coefficient of thermal expansion thereof, and minimize defects caused by surface friction with the glass panel <NUM> due to the low hardness thereof. The thermal conductivity may be measured in accordance with ASTM E1530 using, for example, DTC300 available from TA Instruments (https://www. tainstruments. com/dtc-<NUM>/?lang=ko). The coefficient of thermal expansion may be measured in accordance with ASTM E831, E1545, D696, D3386, ISO <NUM>: Part <NUM>-<NUM>, using, for example, TMA450 available from TA Instruments (https://www. com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=<NUM>&ved=2a hUKEwjrusOEhNrvAhUizlsBHercApOQFjABegQIAxAD&url=http%3A%2F%2Fwww. kr%2Findex. php%2Ffile%2Fdownload%2Ffile_no%2F1228%2Fmod%2Fattach&usg=AOvVaw021uroc290U_Wis3 wP-ffB). As for the hardness, Rockwell, Brinell, or Shore hardness may be measured.

In addition, the contact support portion <NUM> must be configured to prevent warpage caused by suction force or the like and prevent the edges from being distorted when holding the glass panel <NUM>.

The base portion <NUM> is a portion supporting the contact support portion <NUM>. The base portion <NUM> must be configured to properly support the contact support portion <NUM> so that no gap is formed therebetween. The base portion <NUM> must also be configured so that suction force is uniformly applied to the entire surface (i.e., entire suction holes) of the contact support portion <NUM>.

In some embodiments, the first material may be implemented using a carbon material, such as isotropic graphite, for example, available from Ibiden Co. The contact support portion <NUM> formed from the carbon material having low thermal conductivity may prevent a temperature increase in the glass panel <NUM>, thereby protecting the glass panel <NUM> against heat damage. The low coefficient of thermal expansion may prevent a size change during the heat chamfering. In addition, the soft property of the carbon material contributes to the prevention of scratches or the like on the surface of the glass panel <NUM>. The specification of the contact support portion <NUM> formed from the carbon material according to some embodiments is illustrated in Table <NUM> below.

In some embodiments, the second material may be implemented using aluminum (Al) or an aluminum alloy, such as Al <NUM> (i.e., an alloy containing magnesium (Mg) and silicon (Si)). Al has good machinability and high strength, and is lightweight. In addition, due to high thermal conductivity, Al allows cooling to rapidly take place even with the hot body <NUM> at a high temperature.

A shell-shaped support unit used in the related art holds the glass panel <NUM> by clamping the glass panel. However, this support unit of the related art has drawbacks, such as a relatively long loading time and inconvenience. In addition, both surfaces of the glass panel <NUM> are in contact with the support unit, thereby disadvantageously making it difficult to accurately adjust an overhang to be described below.

In some embodiments, a plurality of suction holes <NUM> configured to hold the glass panel <NUM> by suction force may be formed in the surface of the contact support portion <NUM>. The suction holes <NUM> may be connected to a vacuum pump producing low air pressure. When the surface of the glass panel <NUM> is held by vacuum suction, no fixing tools are required to be provided on side portions of the glass panel <NUM> to hold the glass panel <NUM>. Thus, the contact between the hot body <NUM> and the glass panel <NUM> may be smoothly performed along the four edges of the glass panel <NUM>.

For the thin glass panel <NUM> which is apt to easily sag and bend, the support unit must be designed such that the glass panel <NUM> is not deformed when the glass panel <NUM> is held by the support unit, in particular, by suction. When the suction force is too great, wrinkles may be formed on portions of the glass panel <NUM> around the suction holes <NUM>. In contrast, when the suction force is too low@, the glass panel <NUM> may not be properly held. A deformation in the glass panel <NUM> may inhibit uniform heat chamfering.

The number and size of the suction holes <NUM> may be minimized to prevent the warpage of the glass panel <NUM>. For example, in the heat chamfering of the thin glass panel <NUM> having a thickness of <NUM>, the radius of the suction holes <NUM> may be <NUM>. In addition, in some embodiments, the suction holes <NUM> may be located inside the edge of the contact support portion <NUM> while being spaced apart from the edge by a distance in a range from <NUM> to <NUM>. In some of such embodiments, the suction holes <NUM> may be located inside the edge of the contact support portion <NUM> while being spaced apart <NUM> from the edge. In some embodiments, the pitch between the suction holes <NUM> may be <NUM>. The suction holes <NUM> having such dimensions may contribute to reliably holding and preventing the glass panel <NUM> from being distorted. The suction holes <NUM> may be located along peripheral portions of the contact support portion <NUM> and not on the central portion of the contact support portion <NUM>. The sizes of the suction holes <NUM> according to some embodiments are illustrated in Table <NUM> below.

The contact support portion <NUM> may include a first surface facing the glass panel <NUM> and a second surface opposing the first surface. The base portion <NUM> may include a third surface facing the second surface of the contact support portion <NUM>. In some embodiments, a channel <NUM> communicating with the plurality of suction holes <NUM> of the contact support portion <NUM> may be formed in the third surface of the base portion <NUM> along peripheral portions of the base portion <NUM>. In addition, one or more grooves <NUM> connecting a vacuum hole <NUM> and the channel <NUM> may be formed in the top surface of the base portion <NUM>.

In some embodiments, the contact support portion <NUM> and the base portion <NUM> may have mating stepped portions <NUM> and <NUM> provided along peripheral portions thereof such that the stepped portions <NUM> and <NUM> are engaged with each other. In some embodiments, the channel <NUM> may be located inside the stepped portions. These embodiments may minimize the leakage of vacuum. In some embodiments, the height of each of the stepped portions <NUM> and <NUM> may be about <NUM>.

In some embodiments, the edges of the glass panel <NUM> need to outwardly overhang the support unit. The overhang ensures that the strip 100a having a sufficient width may be peeled off and removed during the heat chamfering process. In some embodiments, the thickness of the strip 100a removed by the chamfering may be equal to or smaller than about <NUM>. In this regard, the size of the contact support portion <NUM> may be designed such that the size of the overhang is about <NUM>. When the size of the overhang is too large, sagging may occur in the peripheral portions of the glass panel <NUM>, and the thickness surface of the glass panel <NUM> may not be parallel to the central axis of the hot body <NUM>, thereby reducing the accuracy of the chamfering. When the size of the overhang is too small, it is impossible to peel off the strip 100a in an intended size. Thus, in order to uniformly perform the chamfering along the entire circumference of the edges of the glass panel <NUM>, it is important to align the glass panel <NUM> in position with a predetermined overhang size. Since the position associated with the chamfering is influenced by the size of the overhang, the overhang must be accurately controlled. Preferably, the overhang may be uniform along the entire circumference of the glass panel <NUM>. It is required to accurately align and hold the glass panel <NUM> so that a constant amount of pressure is applied from the hot body <NUM> to the glass panel <NUM> during the heat chamfering. Alignment for the accurate overhang is critical for reliable and accurate process control.

In this regard, the heat chamfering apparatus according to some embodiments of the present disclosure may include an alignment unit <NUM> for aligning the glass panel <NUM> in position. The alignment unit <NUM> may align the edges of the glass panel <NUM> to outwardly overhang the contact support portion <NUM>.

In some embodiments, the alignment unit <NUM> may include a first guide <NUM> configured to be in contact with the support unit and a second guide <NUM> configured to be in contact with some edges of the glass panel <NUM>. The support unit may align the alignment unit <NUM> in position with respect to the position of the support unit by contact with the first guide <NUM>. In addition, the alignment unit <NUM> may align the glass panel <NUM> in position by the second guide <NUM> in contact with the glass panel <NUM>. In some embodiments, the first guide <NUM> and the second guide <NUM> may move integrally. For example, the first guide <NUM> and the second guide <NUM> may be formed integrally.

In some embodiments, the first guide <NUM> may include at least one protrusion protruding toward the support unit (e.g., the contact support portion <NUM>) in a first direction perpendicular to the thickness direction of the glass panel <NUM> and at least one protrusion protruding toward the support unit in a second direction perpendicular to both the thickness direction of the glass panel and the first direction. In some embodiments, the second guide <NUM> may include at least one protrusion protruding toward the glass panel <NUM> in the first direction and at least one protrusion protruding toward the glass panel <NUM> in the second direction. The first guide <NUM> and the second guide <NUM> may be in contact with at least two sides of the support unit and at least two sides of the glass panel <NUM>, respectively, and the present disclosure is not limited thereto.

Referring to <FIG>, for example, the glass panel <NUM> may overhang by <NUM>, the protrusions of the first guide <NUM> may protrude by <NUM>, and the protrusions of the second guide <NUM> may protrude by <NUM>.

After the glass panel <NUM> is placed on the contact support portion <NUM>, the glass panel <NUM> is physically aligned by moving the alignment unit <NUM> until the first guide <NUM> is in contact with the support unit. In this manner, the heat chamfering apparatus according to the present disclosure can rapidly and easily align the glass panel <NUM>.

In some embodiments, further to the first physical alignment of the glass panel <NUM> by the alignment unit <NUM>, the position of the glass panel <NUM> may be accurately determined using a vision system, and then, second alignment of finely moving the glass panel <NUM> may be performed depending on the result of the accurate determination of the position.

Claim 1:
A heat chamfering apparatus comprising:
a support unit configured to support a glass panel (<NUM>); and
a heat chamfering unit configured to heat-chamfer an edge of the glass panel (<NUM>) by applying thermal shock thereto,
wherein the support unit comprises a contact support portion (<NUM>) configured to support the glass panel (<NUM>) while in contact with the glass panel (<NUM>) and a base portion (<NUM>) configured to support the contact support portion (<NUM>), the contact support portion (<NUM>) being formed from a first material, and the base portion (<NUM>) being formed from a second material, further characterised in that the first material has lower thermal conductivity, a lower coefficient of thermal expansion, and lower hardness than the second material.