JP2009149471A - Method and equipment for manufacturing glass plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a through-hole having excellent hole accuracy and surface performance in a drilling step of a glass plate. <P>SOLUTION: The through-hole 4 is formed on the glass plate by intruding a leading drill 1 up to the middle in the thickness direction while cutting from the upper surface of the glass plate 3 and next, moving the leading drill 1 back and after that, intruding a following drill 2 while cutting from the back surface of the glass plate 3. In such a case, the tip part of the following drill 2 is tapered to decrease the diameter from the drum part side toward the drill tip side. The depth of the intrusion of the leading drill 1 from the upper surface of the glass plate 3 is set to satisfy that a relation between the distance L from the topmost of the following drill 2 up to the largest outside diameter part and the distance H from the topmost position in the maximum intrusion of the leading drill 1 up to the back surface of the glass plate 3 is L>H and the outside diameter D2 in the largest outside diameter part of the following drill 2 is set to be larger than the outside diameter D1 in the largest diameter part of the leading drill 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a glass plate and an apparatus therefor, and more particularly, to a technique for forming a through hole in a glass plate by allowing an upper drill and a lower drill to enter from the upper surface side and the lower surface side of the glass plate, respectively.

  As is well known, some glass substrates used for flat panel displays such as plasma display (PDP), field emission display (FED), and electroluminescence display (ELD) are used for exhaust and gas filling in the panel. For this purpose, there is one that forms a through hole in the glass substrate.

  More specifically, the PDP includes a glass substrate as a front plate on which electrodes that transmit visible light are formed, and a glass substrate as a back plate on which electrodes and ribs corresponding to the transmissive electrodes, and phosphors are formed. Are arranged so as to face each other through a predetermined space. Then, a plasma discharge is generated by applying a voltage to a predetermined space between the two plates, and the phosphor on the back plate is caused to emit light by ultraviolet rays generated by the discharge to display an image on the front plate. It is configured. In this case, in order to generate an effective plasma discharge, it is necessary to enclose a gas such as Xe or Ar in the space between the front plate and the back plate. Further, through holes having a diameter of about several millimeters for discharging air and filling the gas are formed at one or a plurality of locations.

  Similarly to the PDP, an FED included in a flat panel display has a glass substrate as a front plate on which electrodes and phosphors are formed and a glass substrate as a back plate on which electrodes and an electron source are formed facing each other. Consists of. Then, by applying a voltage between the two plates, the electrons emitted from the electron source collide with the phosphor, and the phosphor emits light by this collision to display an image on the front plate. Yes. Also in this case, since the space between the front plate and the back plate needs to be high vacuum, one or a plurality of through-holes are formed in the peripheral edge or corner of the back plate as in the case of the glass substrate for PDP. It is formed.

  This type of through-hole allows the lower drill to retreat from the lower surface of the glass substrate to the middle position in the thickness direction of the glass plate, and then retracts the lower drill, and then causes the upper drill to enter from the upper surface of the glass substrate. Usually, it is formed.

  By the way, in the manufacturing process of PDP and some FED, in order to form a transparent electrode, fluorescent substance, a rib, and other elements on each glass substrate, heat processing processes, such as baking, are provided. In this heat treatment step, if a defect such as a microcrack is present in the glass substrate, a stress concentration site such as the tip of the microcrack may be the starting point during heating or cooling, leading to a situation where the glass substrate is damaged. Since this type of damage tends to occur starting from the exhaust holes (through holes) on the back plate, more precisely, the irregularities, chips, microcracks, etc. present on or around the inner peripheral surface of the through holes are damaged. Therefore, it is important to remove these defective portions as much as possible to improve the surface properties of the through holes.

Here, Patent Document 1 below discloses a method of forming a through-hole in a sheet glass using upper and lower drills. That is, in this document, the upper and lower drills are both cup-shaped core drills (cylindrical drills), and the lower core drill has an outer diameter smaller than that of the upper core drill and larger than its inner diameter. A method of forming a through hole in a plate glass has been proposed. According to this method, first, an annular recess is formed from the lower surface side of the sheet glass by the lower core drill (preceding drill), and then, with the intrusion of the upper core drill (following drill) from the upper surface side of the sheet glass, The through hole is formed by scraping the outer peripheral portion of the recess by the upper drill (following drill) by the difference in outer diameter between the two drills.
JP 54-126215 A

  The method described in Patent Document 1 prevents a decrease in the hole diameter accuracy caused by the core rotation of the drill rotating shaft, and also has a peculiar problem caused by using a cylindrical drill on both the upper and lower sides, that is, due to the upper and lower drills. The purpose is to solve the problem that a small uneven surface is formed in the region between the upper and lower perforations. However, since the region of the outer diameter difference in the outer peripheral portion of the annular recess is scraped off by the annular flat end surface provided at the tip of the upper core drill (following drill), the cutting resistance becomes relatively large. . For this reason, the surface roughness of the inner peripheral surface of the hole after processing increases, and micro cracks may occur.

  In view of the above circumstances, it is an object of the present invention to make it possible to form through holes with good hole accuracy and surface properties in a glass plate punching process.

  The solution to the above problem is achieved by the glass plate manufacturing method according to the present invention. In other words, this glass plate manufacturing method involves cutting from one end surface of the glass plate and intruding the preceding drill to the middle in the thickness direction, then retracting the preceding drill, and thereafter, cutting from the other end surface of the glass plate. In a glass plate manufacturing method including a drilling step in which a row drill is inserted to form a through hole in the glass plate, the subsequent drill has a shape that gradually decreases in diameter from the drill body toward the tip of the drill. The penetration depth from one end surface of the glass plate is determined from the axial distance L from the tip of the succeeding drill to the tip side end portion of the drill body which is the maximum outer diameter portion, and the tip position at the time of maximum penetration of the preceding drill. The distance H to the other end surface of the glass plate is set so as to satisfy the relationship L> H, and the outer diameter D2 at the maximum outer diameter portion of the succeeding drill is larger than the outer diameter D1 at the maximum outer diameter portion of the preceding drill. Is also set larger It characterized with a point.

  Thus, in the above-described manufacturing method, the subsequent drill has a shape that gradually decreases in diameter from the drill body toward the drill tip, and the maximum outer diameter D2 of the subsequent drill is greater than the maximum outer diameter D1 of the preceding drill. Since it is set large, the inner peripheral surface of the bottomed hole formed by the preceding drill is provided at the tip of the succeeding drill when the trailing drill is scraped by the maximum outer diameter difference (D2-D1) of both drills. The reduced diameter region first comes into contact with the outer diameter difference region, and is gradually scraped from the inner diameter side to the outer diameter side as the drill enters and moves. Therefore, compared to a drill having a flat end surface, the region of the outer diameter difference can be scraped with a small resistance, suppressing the occurrence of microcracks or the like on the inner peripheral surface of the through hole after processing or in the vicinity thereof, A through-hole having good surface properties can be obtained.

  In addition, in the manufacturing method described above, the axial distance L from the tip of the succeeding drill to the tip side end of the drill body which is the maximum outer diameter portion, and the tip position at the time of maximum penetration of the preceding drill, the glass plate Since the penetration depth of the preceding drill is set so that the distance H to the other end surface satisfies the relationship of L> H, before the maximum outer diameter portion of the succeeding drill starts to penetrate the glass plate, the cutting edge Reaches the tip position of the hole already formed by the preceding drill. Thereafter, the tip of the succeeding drill is inserted into the bottomed hole already formed by the preceding drill, and further penetrates in a form guided by this hole. Therefore, by removing the outer peripheral portion of the bottomed hole in a state in which the core blur of the subsequent drill is suppressed, the cutting allowance can be made as uniform as possible, and the surface property of the inner peripheral surface after the processing can be changed. It can be made better. Further, the portion on the other end surface side of the glass plate in the inner peripheral surface of the through hole is also formed by cutting with a subsequent drill in a state where core blur is suppressed. Thereby, the surface property of the inner peripheral surface of the hole obtained after processing the subsequent drill can be made good over the entire length of the hole.

  In this case, the ratio D1 / D2 of the maximum outer diameter D1 of the preceding drill to the maximum outer diameter D2 of the succeeding drill is preferably set to 0.7 or more and 0.95 or less.

  Thus, the reason why the maximum outer diameter ratio D1 / D2 of both drills is set in the above range is as follows. That is, although set based on the experimental results described later, by setting the maximum outer diameter ratio D1 / D2 to 0.95 or less, the outer peripheral portion of the bottomed hole formed by the preceding drill is effectively scraped off. As a result, the strength of the glass plate can be improved. Of course, this upper limit value functions as an effective numerical value only when the penetration depth of the preceding drill is set so as to satisfy the relationship of L> H. This is because by allowing the subsequent drill to enter in a state in which the core blur is suppressed, even if the machining allowance is small, it is possible to surely remove the micro cracks generated during the previous drilling. In addition, the maximum outer diameter ratio D1 / D2 is set to 0.7 or more because an excessively large machining margin for the bottomed hole by the trailing drill is not necessary for removing the microcracks. This is because there is a possibility that new cracks are induced instead of scraping.

  Moreover, it is preferable that the part which is gradually diameter-reduced toward the drill front-end | tip from the drill trunk | drum of the subsequent drill mentioned above is connected smoothly with the drill trunk | drum.

  Thus, the cutting resistance at the maximum outer diameter portion is reduced when the succeeding drill enters the glass plate by smoothly connecting the drill diameter reduction region of the succeeding drill and the drill body. . Therefore, the probability of occurrence of microcracks in the glass plate can be reduced during intrusion cutting.

  It is preferable that the glass plate manufactured by the above method is a glass substrate for flat panel displays.

  If it does in this way, in the heat treatment process at the time of manufacturing a flat panel display, the situation that a glass substrate is damaged starting from a penetration hole (exhaust hole) can be avoided effectively.

  Moreover, the solution of the said subject is achieved also by the manufacturing apparatus of the glass plate which concerns on this invention. In other words, this glass plate manufacturing apparatus involves cutting from one end surface of the glass plate and intruding the preceding drill to the middle in the thickness direction, then retracting the preceding drill, and thereafter, cutting from the other end surface of the glass plate. In a glass plate manufacturing apparatus configured to intrude a row drill to form a through hole in the glass plate, the subsequent drill has a shape that gradually decreases in diameter from the drill body toward the tip of the drill. The penetration depth from one end surface of the glass plate is the axial distance L from the tip of the succeeding drill to the tip side end of the drill body which is the maximum outer diameter portion, and the tip position at the time of maximum penetration of the preceding drill The distance H from the other end surface of the glass plate is set so as to satisfy the relationship L> H, and the outer diameter D2 at the maximum outer diameter portion of the succeeding drill is the outer diameter D1 at the maximum outer diameter portion of the preceding drill. Set larger than It characterized with a point are.

  According to such an apparatus, the same items as the method described at the beginning of this column are applied, and therefore, the same operation and effect as those of the method can be obtained.

  As described above, according to the method and apparatus for manufacturing a glass plate according to the present invention, it is possible to form a through hole with good hole accuracy and surface properties in the glass plate, and in particular, the hole accuracy and the surface over the entire length of the hole. A through hole having good properties can be formed.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a schematic front view showing a main part of two types of drills which are components of a glass plate manufacturing apparatus according to an embodiment of the present invention. As shown in the figure, the glass plate manufacturing apparatus includes, as main components, a preceding drill 1 and a trailing drill 2 that are arranged so as to be movable up and down with their axial centers coincident with each other. Here, for convenience of explanation, it is assumed that the preceding drill 1 is disposed on the upper side of the glass plate and the subsequent drill 2 is disposed on the lower side of the glass plate.

  Here, with respect to the succeeding drill 2, a drill tapered portion 2a as a reduced diameter region that gradually decreases in diameter toward the tip end is smoothly connected to the upper end of a cylindrical drill body 2x that is the maximum outer diameter portion. Yes. Further, in this embodiment, with respect to the preceding drill 1, a drill tapered portion 1a as a reduced diameter region that gradually decreases in diameter toward the distal end side of the cylindrical drill body 1x that becomes the maximum outer diameter portion is smooth. Connected to.

  In this embodiment, the tapered taper portion 2a, which is the tip of the trailing drill 2, is hemispherical, and the axial distance from the boundary between the drill body 2x and the drill tapered portion 2a to the tip of the drill tapered portion 2a. L corresponds to the radius of the drill body 2x. In other words, the axial distance L from the leading edge of the succeeding drill 2 to the maximum outer diameter portion (the upper end of the drill body 2x) is a half value of the maximum outer diameter D2 described later. The drill tapered portion 1a of the preceding drill 1 is also preferably a similar hemispherical shape.

  The outer diameter (maximum outer diameter) D1 at the maximum outer diameter portion of the preceding drill 1 is set smaller than the outer diameter (maximum outer diameter) D2 at the maximum outer diameter portion of the subsequent drill 2. In other words, the ratio D1 / D2 of the maximum outer diameter D1 of the preceding drill 1 to the maximum outer diameter D2 of the succeeding drill 2 is set to be less than 1. Here, the maximum outer diameter ratio D1 / D2 is preferably set within a range of 0.7 to 0.95.

  The preceding drill 1 and the following drill 2 having the above-described configuration are formed, for example, by attaching diamond abrasive grains to the surface of a metal main body formed by integrating the drill body portions 1x, 2x and the drill tapered portions 1a, 2a. .

  Next, a procedure for forming a through hole as an exhaust hole in a corner portion of a glass plate (in this embodiment, a glass substrate for PDP) using a leading drill 1 and a trailing drill 2 based on FIG. Will be explained.

  First, as shown in FIG. 2 (a), the preceding drill 1 is arranged above the glass plate 3 in a horizontal posture so that the drill tapered portion 1a is directed downward, and the preceding drill 1 is rotated. By lowering, the drill tapered portion 1a of the preceding drill 1 is entered from the upper side of the glass plate 3 with cutting. At this time, the preceding drill 1 may be allowed to enter the glass plate 3 while supplying the cutting fluid to the entry location of the preceding drill 1. As shown in FIG. 2B, when the drill body 1x of the preceding drill 1 enters the glass plate 3 by a predetermined axial dimension, the descending of the preceding drill 1 is stopped.

  At this time, the distance H from the lower end position on the axial center where the preceding drill 1 has entered the glass plate 3 to the lower surface of the glass plate 3 is shorter than the axial distance L in the following drill 2. Further, as described above, in the process in which the preceding drill 1 enters the glass plate 3 while supplying the cutting fluid, the cutting fluid is sufficiently distributed to the intruding portion by gravity. Therefore, the generation of frictional heat is suppressed by the cooling action of the cutting fluid, and cracks are less likely to occur.

  Thereafter, as shown in FIG. 2C, the preceding drill 1 is lifted to extract the preceding drill 1 from the glass plate 3 and move it to the retracted position. As a result, the glass plate 3 is formed with a non-penetrating upper hole (bottomed hole) 4a that opens only upward.

  Next, as shown in FIG. 2 (d), the subsequent drill 2 is arranged below the glass plate 3 so that the drill tapered portion 2 a is directed upward. In this case, the rear drill 2 is arranged in a state in which the preceding drill 1 previously drilled and its axis are aligned with each other, so that the axis of the bottomed hole 4a already formed in the glass plate 3 and the subsequent drill 2 are arranged. The drilling described later is performed in a state where the axis of the drill 2 is aligned. And as shown in FIG.2 (e), the drill taper part 2a of the subsequent drill 2 penetrate | invades into the glass plate 3 from lower side, for example by raising the subsequent drill 2 supplying cutting fluid to the penetration | invasion location. I will let you. At this time, a core crack of the trailing drill 2 and insufficient cooling due to the drop of the cutting fluid due to gravity cause a micro crack around the drill tapered portion 2a and the front portion 5 in the penetration direction.

  And by continuing raising the subsequent drill 2 and making it penetrate | invade into the glass plate 3 further, as shown in FIG.2 (f), the front-end | tip of the drill taper part 2a of the bottomed hole 4a of the glass plate 3 is carried out. Reach the bottom edge. At this time, since the above-described relationship of L> H is satisfied, the drill body 2x (maximum outer diameter portion) of the succeeding drill 2 has not yet entered the glass plate 3.

  By continuing to raise the trailing drill 2 from such a state, as shown in FIG. 2 (g), the drill tapered portion 2a enters the bottomed hole 4a of the glass plate 3, The trailing drill 2 can enter the glass plate 3 without causing a core blur. In addition, the maximum outer diameter portion (drill body portion 2x) of the succeeding drill 2 in which the bottomed hole 4a and the shaft center coincide with each other and the maximum outer diameter ratio D1 / D2 is set as described above is the glass plate 3 and the bottomed portion. By entering the hole 4a, the periphery 6 of the bottomed hole 4a is scraped gradually and evenly from the inside toward the outside by an amount corresponding to the outer diameter difference D2-D1. Thereby, the micro crack which has already arisen in the above-mentioned penetration direction front part 5 grade | etc., As well as the micro crack which has arisen in the inner peripheral surface of the bottomed hole 4a or its vicinity can be removed. When the leading drill 1 is inserted while supplying the cutting fluid as described above, the hole drilled by the trailing drill 2 and the bottomed hole 4a drilled by the leading drill 1 penetrate (communicate). As a result, the upper cutting fluid flows into the hole from the lower side. Thereby, the frictional heat of the trailing drill 2 can be suppressed.

  Then, by further raising the trailing drill 2 from the above position, when the drill body 2x of the trailing drill 2 penetrates to the upper surface side of the glass plate 3, the through hole (exhaust hole) 4 is drilled. Finish. Thereafter, the drilling process is completed when the trailing drill 2 is moved down to the retracted position shown in FIG. As a result, a through hole 4 having a diameter corresponding to the maximum outer diameter D2 of the trailing drill 2 (the outer diameter of the drill body 2x) is formed in the glass plate 3.

  In addition, although the case where the tip shape of each drill 1 and 2 was hemispherical was illustrated in the said embodiment, of course, the said tip shape can each be arbitrarily changed within the scope of the present invention. For example, one or both of the drill tapered portions 1a and 2a can be formed into a semi-elliptical sphere whose major axis coincides with the drill axis. Alternatively, one or both of the drill taper portions 1a and 2a is formed into a tapered shape, and the taper portions 1a and 2a are smoothly formed by the drill body portions 1x and 2x and an appropriate R-shaped annular surface. It can also be connected.

  In addition, the through-hole drilling process according to the above description is suitable when, for example, the through-hole has a diameter of about 1 mm to about 5 mm, and as the through-hole length, in other words, around the through-hole. It is suitable when the thickness of the plate glass is about 0.5 mm to 4 mm.

  In the above description, the present invention is applied to the case where the through hole (exhaust hole) is formed in the glass substrate for PDP. However, the case where the through hole is formed in the glass substrate for FED or ELD in addition to this. In addition, the present invention can be applied to the same manner, and of course, when it is necessary to form a through hole in the glass plate where cracks are a problem, the present invention can be applied to all of them. .

  In order to confirm the effect of the present invention, the following tests and examinations were conducted. Items common to the examples of the present invention (Examples 1 to 4) and the comparative example (Comparative Example 1) will be described first. First, 10 glass substrates for PDP each having a horizontal dimension of 500 mm, a vertical dimension of 600 mm, and a thickness of 1.8 mm were prepared for the glass plates forming the through holes. Each of the preceding drill and the following drill is composed of a drill body and a hemispherical drill tapered portion, and the exhaust gas is exhausted to the glass substrate with a drill rotation speed of 5000 rpm and a drill feed speed of 0.2 mm / sec. A through hole to be a hole was formed. Further, in the following drill, the axial distance L shown in FIG. 1 is 1.0 mm, and the penetration distance H of the preceding drill into the glass plate shown in FIG. 2B is 0.7 mm. . In each case, the preceding drill was entered from the upper side of the glass substrate, and the subsequent drill was entered from the lower side of the glass substrate for drilling.

  And after making all the outer diameter D2 in the largest outer diameter part of a subsequent drill into 2.0 mm, the outer diameter D1 in the largest outer diameter part of a preceding drill was varied, and the drilling process was implemented. That is, the examples in which the maximum outer diameter ratio D1 / D2 is included in the range of 0.7 to 0.95 are examples (Examples 1 to 4), and the outer diameter ratio D1 / D2 is 1 in the comparative example (comparison). A drilling step was carried out as Example 1).

The glass substrate with the exhaust holes formed as described above is damaged by applying an appropriate thermal history or thermal history and mechanical load, and weibull against the fracture strength data obtained by fracture surface analysis of the damaged fracture surface. Plot processing was performed, and the fracture strength at a failure probability of 10% was calculated for each example and comparative example. The results are shown in Table 1 below.

  According to Table 1 above, as the maximum outer diameter ratio D1 / D2 approaches 1, in other words, as the difference D2-D1 in the maximum outer diameter between the preceding drill and the succeeding drill decreases, the drill diameter becomes the same diameter. Compared to the case, an improvement in fracture strength is observed. Specifically, as shown in Example 1, when the maximum outer diameter ratio D1 / D2 was set to 0.95, an improvement in strength of about 30% was recognized compared to the case of the same diameter. This strength improvement effect is recognized even when the maximum outer diameter ratio D1 / D2 is somewhat apart from 1, and if at least D1 / D2 is 0.7 or more, the strength improvement effect is greater than the case of the same diameter. It came to confirm that it was recognized.

The front view which shows the principal part of the precedent drill and subsequent drill which are the main components of the manufacturing apparatus of the glass plate which concerns on one Embodiment of this invention. FIG. 2A to FIG. 2H are schematic longitudinal front views sequentially showing the state of implementation of a perforation process in the glass plate manufacturing method according to one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Leading drill 1a Drilling taper part 1x of a preceding drill Drill body part 2 of a preceding drill Trailing drill 2a Drilling taper part 2x of a succeeding drill Drill body part 3 of a following drill 3 Glass plate 4 Through-hole (exhaust hole)
4a Bottomed hole 6 Surrounding part of bottomed hole (rear drill removal part)

Claims (5)

After cutting the leading drill from the one end surface of the glass plate to the middle in the thickness direction, the leading drill is retracted, and then the trailing drill is inserted from the other end surface of the glass plate with cutting. In the manufacturing method of the glass plate including the perforation process of forming a through hole in the plate,
The subsequent drill has a shape that gradually decreases in diameter from the drill body toward the drill tip,
The depth of penetration of the preceding drill from the one end surface of the glass plate is an axial distance L from the tip of the succeeding drill to the tip side end of the drill body which is the maximum outer diameter portion, and the leading drill. And the distance H from the tip position at the time of maximum penetration to the other end surface of the glass plate is set so as to satisfy the relationship of L> H,
An outer diameter D2 at the maximum outer diameter portion of the trailing drill is set to be larger than an outer diameter D1 at the maximum outer diameter portion of the preceding drill.   The method for producing a glass sheet according to claim 1, wherein a ratio D1 / D2 of the maximum outer diameter D1 of the preceding drill to the maximum outer diameter D2 of the trailing drill is set to 0.7 or more and 0.95 or less.   The method for producing a glass plate according to claim 1 or 2, wherein a portion of the succeeding drill that gradually decreases in diameter from the drill body toward the drill tip is smoothly connected to the drill body.   The said glass plate is a glass substrate for flat panel displays, The manufacturing method of the glass plate in any one of Claims 1-3 characterized by the above-mentioned. After cutting the leading drill from the one end surface of the glass plate to the middle in the thickness direction, the leading drill is retracted, and then the trailing drill is inserted from the other end surface of the glass plate with cutting. In a glass plate manufacturing apparatus configured to form a through hole in a plate,
The subsequent drill has a shape that gradually decreases in diameter from the drill body toward the drill tip,
The depth of penetration of the preceding drill from the one end surface of the glass plate is an axial distance L from the tip of the succeeding drill to the tip side end of the drill body which is the maximum outer diameter portion, and the leading drill. And the distance H from the tip position at the time of maximum penetration to the other end surface of the glass plate is set so as to satisfy the relationship of L> H,
An apparatus for producing a glass plate, wherein an outer diameter D2 at the maximum outer diameter portion of the trailing drill is set to be larger than an outer diameter D1 at the maximum outer diameter portion of the preceding drill.

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