Method and apparatus for processing edge of glass by using high frequency induction heater

Abstract

Method and apparatus for heat treating and processing an edge of a large thin glass sheet used for a liquid crystal TV or the like. The method for processing an edge of a glass substrate according to the present invention is characterized by cutting an edge of a glass substrate by bringing a heated member into contact with the edge of the glass substrate that is cooled, and then moving the heated member. According to the present invention, provided is a new method of removing the edge of glass in a strip shape without producing dust. Also, according to the method of the present invention, since it is unnecessary to heat the glass at a high temperature, a large furnace is not necessary. Further, since a post-processing operation such as preheating or annealing is unnecessary, the manufacturing process is highly simplified.

Claims

1. A method of processing an edge of a moving cooled glass substrate, the method comprising cutting the edge of the moving cooled glass substrate while bringing by contacting the edge of the moving cooled glass substrate with a heating member, wherein a contact pressure between the heating member and the edge of the moving cooled glass substrate is 0.1 to 3.0 Kg.sub.f/cm.sup.2.

2. The method of claim 1, wherein the edge of the moving cooled glass substrate is cut into a strip shape.

3. The method of claim 1, wherein the heating member includes a rod-type needle heated by an induction-heating.

4. The method of claim 1, wherein the edge of the moving cooled glass substrate is maintained under cutting conditions including; a temperature of the moving cooled glass substrate of 0 to 10 C., a temperature of the heating member higher than a temperature of the moving cooled glass substrate by 200 to 500 C., and a movement speed of the moving cooled glass substrate of 0.5 to 5 cm/s.

5. The method of claim 1, wherein the heating member is a heating member induction-heated with high frequency having a range of frequency of 200 to 500 Hz.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 illustrates a method of flame-processing the edge of a glass sheet according to the related art;

(2) FIG. 2 is a cross-sectional view of a cooling bed for cooling a glass sheet while moving it according to the present invention;

(3) FIG. 3 is a view showing the contact state between the cooling bed, the glass sheet and a heating member according to the present invention;

(4) FIG. 4 is a photograph showing the glass sheet of which an edge is cut, and a cut piece cut from the glass sheet;

(5) FIG. 5 illustrates the contact states between the heating member and the edge of the glass sheet according to the present invention; and

(6) FIG. 6 shows photographs of a transparent edge (a) of the glass sheet cut by the present cutting apparatus and of an opaque edge (b) of the glass sheet ground by a conventional grinder.

BEST MODE

(7) Hereinafter, embodiments of the present invention will be described in detail. The embodiments are described merely for illustrative purposes, and do not limit the invention. The scope of the present invention is defined by the attached claims.

(8) FIG. 2 is a cross-sectional view of a cooling bed for cooling a glass sheet while moving it according to the present invention; FIG. 3 is a view showing the contact state between the cooling bed, the glass sheet, and a heating member according to the present invention; FIG. 4 is a photograph showing the glass sheet of which edge is cut, and a cut piece cut from the glass sheet; and FIG. 5 illustrates the contact states between the heating member and the edge of the glass sheet according to the present invention.

(9) As shown in FIG. 2, a glass sheet (or glass substrate) 112 is positioned on an upper portion of a cooling bed 111. The size of the cooling bed 111 is preferably substantially the same as that of the glass sheet 112, but it may become larger or smaller depending on implementing conditions. The cooling bed 111 is provided therein with a coolant channel 120 for maintaining a constant temperature of the cooling bed 111. Further, the cooling bed 111 is provided on the surface with suction through-holes 113 for suction-fastening of the glass sheet 112. The suction through-holes 113 completely pass through the cooling bed from upper to lower surfaces thereof, and are connected with a vacuum pump to form a vacuum state. The vacuum suction of the glass sheet at the bottom thereof has advantages in that, since fasteners are not required on lateral sides of the glass sheet to fasten the glass sheet 112, the heating member can easily contact the edges of the glass sheet 112.

(10) As shown in FIG. 3, the heating member 114 includes a rod-type body 116 and a conical contact part 117 on an upper end of the body 116.

(11) The heating member 114 is fixed such that a distal end of the body 116 is fixed to a stationary plate 115, keeping itself stationary when contacting the edge of the glass sheet. The heating member is heated by an induction coil 119 connected to a high-frequency induction heater 118. The high-frequency induction heater is commercially available, and the operating condition may vary depending on the state of the glass sheet or surrounding temperature. For example, the operating condition may include 200300 V, 2050 A, 250500 Hz, and a power efficiency of 5090%.

(12) The glass sheet 112 is moved in a Y-axis direction perpendicular to an XZ plane, and an edge thereof is cut into a strip shape 120 by being brought into contact with an inclined surface of the contact part 117.

(13) As shown in FIG. 4, the edge of the glass sheet 112 is cut into the strip shape 120 without forming cut glass particles.

(14) As shown in FIG. 5, a round corner of the glass sheet 112 is formed using the heating member 114. When the glass sheet 112 is moved in an X-axis while the heating member 114 is kept stationary, as shown in section (a), the glass sheet 112 is cut into a strip shape; as shown in section (b), the glass sheet is moved to the corner along X-axis; and as shown in section (c), the glass sheet 112 is moved along an Y-axis. Since the heating member 114 has a conical shape laterally-symmetrical about a Z-axis, the glass sheet 112 can be moved along the Y-axis after being easily rotated in a state being brought into contact with the heating member 114.

(15) As shown in FIG. 6, a photograph of edges of the glass sheet cut from the corners and a comparative photograph of edges of the glass sheet ground from the corners are provided. The cut faces and the ground faces are respectively measured with respect to Rp, Rv, Rz, Ra, Rq, and the measuring results are shown in Tables 1 and 2, respectively. Here, by micrometer unit, Rp is maximum peak Height, Rv is maximum Valley depth, Rz is an average distance between highest peak and lowest peak, Ra is the arithmetic mean of an absolute value, and Rq is a root mean square.

(16) TABLE-US-00001 TABLE 1 Measurements of cut faces Rp Rv Rz Ra Rq 1 2.44 2.11 4.55 0.30 0.46 2 1.78 1.58 3.35 0.26 0.39 3 1.72 1.64 3.36 0.27 0.40 4 1.48 1.55 3.03 0.29 0.44

(17) TABLE-US-00002 TABLE 2 Measurements of ground faces Rp Rv Rz Ra Rq 1 3.90 4.52 8.41 0.53 0.71 2 2.19 3.941 6.13 0.50 0.67 3 1.61 3.48 5.08 0.47 0.65 4 3.39 3.82 7.21 0.48 0.66