JP2001294437A - Chamfering method for glass substrate of liquid crystal display device and heater used for this method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chamfering method of glass substrates for a liquid crystal display device which is capable of chamfering all of the corner parts of the outer peripheral edges of the glass substrate right after parting of the glass substrates without contaminating the glass substrates and further does not damage the display circuits, etc., disposed at the glass substrates. SOLUTION: The chamfering method of the glass substrates for the liquid crystal display device consists in brining heaters into contact with the corner parts at the outer peripheral edges of the glass substrates and chamfering the corner parts by melting the corner parts in the liquid crystal display device consisting of the glass substrates facing each other across liquid crystals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and an apparatus for manufacturing the same, and more particularly to processing a corner portion of an outer peripheral edge of a liquid crystal display panel.

[0002]

2. Description of the Related Art Generally, a liquid crystal display device comprises a liquid crystal display panel comprising a pair of glass substrates opposed to each other with a liquid crystal interposed therebetween, and a driver IC for controlling display of the liquid crystal display panel.
It consists of.

A liquid crystal display panel, which is a main component of the liquid crystal display device, injects liquid crystal into a pair of opposing glass substrates on which input electrodes for inputting control signals are formed, and applies the liquid crystal to the input electrodes. An information signal is displayed by controlling an amount of transmitted light by controlling a polarization component of incident light from the outside by adding an electric signal from an external driver IC.

[0004] Such a liquid crystal display panel is often manufactured by taking a large number of pieces from a large glass substrate in order to be advantageous in terms of cost. As a manufacturing method of this kind, a plurality of liquid crystal display panels are manufactured by first forming a display circuit including a transparent electrode or the like on a pair of large glass substrates, bonding a pair of glass substrates opposed to each other, and dividing the panel. There are two types: a case where the glass substrate is divided during the formation of the display circuit and then a glass substrate is bonded.

[0005] In addition, in order to simplify inspection, mainly in small models, a method of injecting liquid crystal in a state where a plurality of liquid crystal panels are connected, and dividing the liquid crystal display panels into individual liquid crystal display panels after inspection has been performed. I have.

[0006] In any case, the glass substrate is cut by scribing (scratch having a depth of several tens to several hundreds of μm) on the glass surface using a cutter made of a super steel alloy or a diamond, and then applying a physical stress. To break the glass. In the case of such a dividing method, minute cracks or chips, that is, cracks, are generated in the sectional plane due to the scribe. In addition, the cut surface in the cut state is often steep at an acute angle.

In this state, if no processing is performed after the glass substrate is cut, the cross section of the glass substrate is structurally fragile. There is a problem such as the generation of unusual glass dust (cullet). Further, a display control circuit on which an external driver IC or the like is mounted is connected to a TCP (TapeCarrier).
In the case of connecting to an input electrode of a glass substrate using a film-like substrate such as a package, there is also a problem that cutting is likely to occur at a corner of an outer peripheral edge including a partial cross section.

Further, when cullet is generated, the cullet enters the display area of the liquid crystal display device to degrade the display quality and causes a contact failure when the display control circuit is attached to the input electrode of the glass substrate. There is also.

For this reason, the corners of the outer peripheral edge of the liquid crystal display panel are usually chamfered to remove cracks and sharply sharp corners. As this chamfering method, polishing with a grindstone is conventionally known and widely practiced. Further, in addition to grinding with a grindstone, a method of performing a heat treatment with a laser beam to melt and eliminate cracks generated at the corners of the outer peripheral edge has been proposed (for example,
See JP-A-10-111497).

[0010]

In the case of chamfering with a grindstone, cullet is generated as a result of polishing the glass, so that it is necessary to perform cleaning in a later step to remove the cullet. Further, since cutting water is required to perform the polishing, the display circuit surface is contaminated by the cutting water.
For this reason, it is difficult to chamfer the glass substrate before bonding and the liquid crystal display panel before injecting liquid crystal, which must avoid contamination as much as possible, and it is most effective to prevent cracks and cullets immediately after the glass substrate is cut. The chamfer could not be performed.

In addition, when chamfering with a grindstone, it is difficult to chamfer the corners of the outer peripheral edge of the glass substrate located above the input electrodes of the liquid crystal display panel. For this reason, generation of cracks and cullets from this portion could not be prevented, and only an insufficient prevention effect was obtained.

In the case of using a laser beam as a heat source to melt and eliminate cracks at the corners of the outer peripheral edge, the irradiated laser light is refracted when passing through the glass surface and hits a display circuit in the substrate. Then, there is a possibility that the display circuit is destroyed and causes a display failure.

The present invention has been made in view of the above circumstances, and can chamfer all corners of the outer peripheral edge of a glass substrate immediately after cutting the glass substrate without contaminating the glass substrate. An object of the present invention is to provide a method for chamfering a glass substrate of a liquid crystal display device which does not damage a display circuit and the like provided on the glass substrate and a heater used for the method.

[0014]

According to the present invention, in a liquid crystal display device comprising glass substrates opposed to each other with a liquid crystal interposed therebetween, a heater is brought into contact with a corner of an outer peripheral edge of the glass substrate to melt the corner. An object of the present invention is to provide a method of chamfering a glass substrate of a liquid crystal display device, wherein the glass substrate is chamfered.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a glass substrate made of, for example, borosilicate glass, soda-lime glass, low alkali glass, non-alkali glass, silica glass, or the like can be used.

As the liquid crystal sandwiched (injected) between the opposing glass substrates, known liquid crystals such as a smectic liquid crystal and a nematic liquid crystal can be widely used and are not particularly limited.

When melting and chamfering the corner of the outer peripheral edge of the glass substrate, the heater heats the corner to a temperature higher than the strain point temperature of the glass substrate and lower than the softening temperature. By heating the corner of the outer peripheral edge of the glass substrate to such a temperature, surface flow occurs at the corner and chamfering is performed. For example, when borosilicate glass is used for a glass substrate, a suitable heating temperature is about 650 ° C.
８００800 ° C.

A heater used in the method for chamfering a liquid crystal display device according to the present invention includes an elongated heat conductor and a heat source provided on the heat conductor, and a tip of the heat conductor has a corner of an outer peripheral edge of a glass substrate. May be formed.

The groove of the heat conductor is formed to melt and chamfer the corner of the glass substrate so as to conform to the shape of the groove. Also, when the width of the heater is shorter than the length of the outer peripheral edge of the glass substrate, it is necessary to move the heater along the corner while making contact with the outer peripheral edge. Also serves as a guide when moving. For this reason, the shape of the groove of the heat conductor is not particularly limited, and examples thereof include a U shape and a V shape.

For example, when the shape of the groove of the heat conductor is U-shaped, the cross section of the outer peripheral edge of the chamfered glass substrate is formed in an arc shape or a semicircular shape (hereinafter referred to as an R shape in this specification). Can be.

A heating wire or a hydrogen gas burner can be used as a heat source of the heater. The hydrogen gas burner can be composed of a hydrogen gas supply nozzle, an oxygen gas supply nozzle, and an exhaust pipe. Since these heat sources do not contaminate the surrounding atmosphere, they are suitable for use in a liquid crystal display device manufacturing factory where contamination must be avoided as much as possible.

In the present invention, when a plurality of liquid crystal display panels are manufactured by dividing a large glass substrate into a large number of pieces, the glass substrate can be chamfered using the heater immediately after the division. . This makes it possible to prevent the occurrence of cracks from the corners of the outer peripheral edge of the glass substrate in a later step, so that the timing of chamfering the glass substrate during the manufacturing process of the liquid crystal display device is most preferable.

The chamfering can be performed at the above timing because the chamfering method according to the present invention does not contaminate the glass substrate during the chamfering, unlike the conventional chamfering method using a grindstone. Further, since the glass substrate is not contaminated, a cleaning step after chamfering is not required.

Further, since the chamfering is performed by directly contacting the heater with the corner of the outer peripheral edge of the glass substrate and heating the same, a display circuit formed on the glass substrate as in a conventional chamfering method using a laser beam is used. It does not damage the product.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments shown in the drawings. The present invention is not limited by the embodiment.

An embodiment of the present invention will be described with reference to FIGS. First, as shown in FIG.
Glass substrates 1a and 1b made of borosilicate glass are prepared. Both the glass substrates 1a and 1b have d1 of about 550 m.
m and w1 are about 650 mm, and t is about 1.1 mm. On one side of each of the glass substrates 1a and 1b, a display circuit 2 made of ITO and an input electrode 3 made of aluminum are formed.

Next, a spacer (not shown) made of silica having a diameter of about 5 μm is sprayed, and as shown in FIG. 1B, a thermosetting epoxy is placed around the display circuit 2 of the glass substrate 1a. Apply resin (not shown) with a width of about 1 mm,
After the alignment with the glass substrate 1b, the substrates are overlaid as shown in FIG. After overlapping, pressure bonding is performed at a temperature of about 160 ° C. for about 3 hours, and the glass substrates 1 a and 1 b
Complete the lamination.

Next, as shown in FIG. 1D, a predetermined line 5 indicated by a broken line is scratched to a depth of about 200 μm using a diamond cutter 4. After the scratch, a force is applied along the predetermined line 5 to divide the glass substrates 1a and 1b into four along the predetermined line 5.

FIG. 2 shows one of the divided glass substrates 1a and 1b. Further, a glass substrate 1a shown in FIG.
FIG. 3 shows an enlarged view of a portion A of 1b. As shown in FIG. 3, cracks 7 have occurred at the corners 6 of the outer peripheral edges of the glass substrates 1a and 1b.

For this reason, as shown in FIG. 4, the U-shaped groove 14 formed at the tip of the heat conductor 12 of the heater 8 is brought into contact with the corner 6 of the outer peripheral edge of the glass substrate 1a, 1b while the outer peripheral edge is formed. Is chamfered by moving along the longitudinal direction of the corner 6. Specifically, as shown in FIG. 5, using a heater moving device 21, a glass substrate 1 placed on a stage 22 is used.
The heater 8 may be moved along the corner 6 of the outer peripheral edge of a, 1b. The heater moving device 21 includes first, second, and third drive shafts (not shown),
It can be freely moved in the directions indicated by arrows in the figure, that is, in the vertical and horizontal directions and the front and rear directions. The first, second, and third drive shafts are driven by a motor (not shown) having a speed control function, and determine a contact time between the glass substrates 1a and 1b and the heater 8, a moving speed of the heater 8, and the like. It can be controlled with high accuracy.

At this time, the heater 8 is connected to the glass substrates 1a and 1b.
Is heated so that the corner 6 of the outer peripheral edge of the above becomes about 650 ° C. to 800 ° C. This is because the borosilicate glass has a strain point temperature of about 600 ° C. and a softening temperature of about 850 ° C.

The deep crack 7 shown in FIG. 3 has a depth of about 100 μm to 150 μm. For this reason, as shown in FIG. 4, the corners 6 of the outer peripheral edges of the glass substrates 1a and 1b have r shown in FIG.
It is chamfered into an R shape of about m.

As shown in FIG. 4, the corner 6 of the outer peripheral edge of the glass substrate 1b located above the input electrode 3 is also chamfered. Corner 6 of outer peripheral edge of glass substrate 1b
Are locations where chamfering was difficult with the conventional chamfering method using a grindstone.

After the chamfering is performed in this manner, liquid crystal is injected using a bell jar or the like in the same manner as in a conventional manufacturing method to complete a liquid crystal display device.

Next, the heater 8 used in the method of manufacturing the liquid crystal display device according to the above embodiment will be described with reference to FIGS. FIG. 6 is an explanatory diagram illustrating a schematic configuration of the heater 8. As shown in FIG. 6, the heater 8 includes an elongated heat conductor 12 and a heat source 13, and a U-shaped groove 14 is formed at the tip of the elongated heat conductor 12. Heat conductor 12 and heat source 1
3 is housed in a main body 15 made of a thermal insulator. The heat conductor 12 is formed of ceramic, and d2 is about 2 mm. Further, the width of the heat conductor 12 in contact with the substrate 1a or 1b, that is, w2 shown in FIG. 4 is about 10 mm. Although the dimension of w2 in FIG. 4 is not particularly limited, it is about 3 m
m to about 50 mm. Further, the heat conductor 12 may be formed of a metal such as copper metal whose surface is electrically insulated.

FIG. 7 is an enlarged view of the tip of the heat conductor 12. As shown in FIG. 7, the U-shaped groove 14 formed at the tip of the heat conductor 12 is formed such that d3 shown in FIG. 7 is 400 μm and d4 is 150 μm.

On the other hand, the heat source 13 shown in FIG. 6 is a nichrome wire, which is wound around the heat conductor 12.
The heating value required for the heater 8 is about 11 J / s. This value can be determined as follows. For example, it is assumed that the corner 6 of the outer peripheral edge is chamfered over 1 cm so that r shown in FIG. 4 is 200 μm (0.02 cm). The material of the glass substrate to be chamfered is borosilicate glass, and the heater 8 and the glass substrates 1a, 1
Assume that there is no thermal loss at b. The thermal conductivity of the borosilicate glass is set to k = 0.015 J / cm · sec · ° C.
If the edge 6 is heated to 800 ° C. to a depth of 0.02 cm, the required heat value C is expressed by the following equation. C = (T ₁ −T ₀ ) / (L / kA)

Here, T ₁ is the ultimate temperature (800
C), T ₀ is the initial temperature (here, 25 ° C.), L
Is the depth to which heat is applied (0.02 cm), k is the thermal conductivity (0.015), A is the area to which heat is applied (1 cm × 0.0
2 cm = 0.02 cm ² ). Therefore, the calorific value C required for the heater is: C = 775 / (0.02 / 0.0003) = 775 /
66.6 = 11.7.

That is, when the heater 8 has a heating value of about 11 J / s, the heater 8 is moved at a speed of about 1 cm / s along the corner 6 of the outer peripheral edge of the glass substrates 1a and 1b. For example, the corners 6 of the outer peripheral edges of the glass substrates 1a and 1b can be melted and chamfered. Also, the glass substrate 1
When the materials of a and 1b are changed, it is preferable to calculate the calorific value required for the heater 8 based on the above equation, and change the specifications of the heater or adjust the output.

FIG. 8 shows an example in which the heat source 13 is a hydrogen gas burner. As shown in FIG. 8, the heat source 13 is a hydrogen gas burner including a hydrogen gas supply nozzle 16, an oxygen gas supply nozzle 17, and an exhaust pipe 18. Other configurations and dimensions of each part are the same as those of the heater shown in FIGS.

In the heater 8 used in the method of manufacturing the liquid crystal display device according to the present invention, a nichrome wire or a hydrogen gas burner is used as the heat source 13 as described above. However, since these heat sources 13 do not contaminate the atmosphere in the factory, they are contaminated. It is suitable for use in a liquid crystal display device manufacturing plant in which it is necessary to avoid as much as possible.

[0042]

According to the present invention, the heater is brought into contact with the corner of the outer peripheral edge of the glass substrate, and the edge is melted and chamfered, so that the glass substrate is not contaminated. A method and a method for chamfering a glass substrate of a liquid crystal display device which can be chamfered immediately after the division and all the corners of the outer peripheral edge of the glass substrate without damaging a display circuit or the like provided on the glass substrate. Can be provided.

[Brief description of the drawings]

FIG. 1 is a process diagram showing a method for manufacturing a liquid crystal display device using a method for chamfering a glass substrate of a liquid crystal display device according to the present invention.

FIG. 2 is a perspective view showing one of the divided glass substrates shown in FIG. 1 (d).

FIG. 3 is an enlarged view of a portion A of the glass substrate shown in FIG. 2;

FIG. 4 is a perspective view showing that the glass substrate shown in FIG. 3 is chamfered using a heater.

FIG. 5 is a perspective view showing chamfering using a heater moving device.

FIG. 6 is an explanatory diagram showing a schematic configuration of a heater using a nichrome wire as a heat source.

FIG. 7 is an enlarged view of a tip portion of the heater shown in FIG.

FIG. 8 is an explanatory diagram showing a schematic configuration of a heater using a hydrogen gas burner as a heat source.

[Explanation of symbols]

 1a, 1b: Glass substrate 3: Input electrode 6: Corner of outer peripheral edge 8: Heater 12: Thermal conductor 14: U-shaped groove

Claims (5)

[Claims] 1. A liquid crystal display device comprising glass substrates opposed to each other with a liquid crystal interposed therebetween, wherein a heater is brought into contact with a corner of an outer peripheral edge of the glass substrate, and the corner is melted and chamfered. Method for chamfering a glass substrate of a liquid crystal display device. 2. A heater for use in the method for chamfering a liquid crystal display device according to claim 1, comprising a long and thin heat conductor, a heat source provided on the heat conductor, and a tip of the heat conductor. A heater, wherein a groove corresponding to a corner of an outer peripheral edge of a substrate is formed. 3. The heater according to claim 2, wherein the heat source is a heating wire. 4. The heat source is a hydrogen gas burner.
A heater according to claim 1. 5. The hydrogen gas burner includes a hydrogen gas supply nozzle, an oxygen gas supply nozzle, and an exhaust pipe.
A heater according to claim 1.