JP2000026127A - Method for adhesion of glass plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the method capable of instantaneously adhering a glass plate with a companion substance to be adhered, by which, e.g. the inside surface and outside surface of two sheets of glasses constituting flat panel display can be adhered simply and exactly. SOLUTION: The glass plate 1 is adhered closely to a companion plate 3 to be adhered, through a thin film 2 capable of absorbing laser lights 4 and 4' transmitting the glass plate, and then the thin film 2 is radiated with the laser light through the glass plate while keeping the adhered state, thereby the two substances holding the thin film between them are welded each other by the heat generated from the thin film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of bonding glass plates suitable for bonding two front and back glass plates constituting a flat display panel such as a liquid crystal display panel and a plasma display panel.

[0002]

2. Description of the Related Art Various thermal processes exist before a flat display panel such as a liquid crystal display panel or a plasma display panel is completed.
At this time, it is necessary to gradually lower the firing temperature in order to minimize the influence on the material fired in the previous step. The final heat step is the hermetic bonding of the front and back glass substrates. As an example, an airtight bonding process of a plasma display panel is conceptually shown in FIG. When the front glass substrate 101 and the rear glass substrate 102 are bonded to each other, the glass frit 1 having a width W along the outer periphery is provided on the inner surface of the front glass substrate 101.
03 is attached. The attachment of the glass frit 103 is performed by screen printing or a dispenser. As the glass frit used in this process,
Those which can be fired at a low temperature with a large amount of lead components are employed. An example of the sealing temperature profile is shown in FIG. In order to bake out the binder contained in the frit, the temperature is once maintained at 300 ° C., and then the glass frit is melted at 450 ° C. When the panel temperature is increased, the substrate and the frit are not yet bonded, so that the temperature can be increased quickly. However, if a temperature difference occurs in each part after the frit has hardened, the panel is broken, so it is necessary to take sufficient time for the temperature to decrease. The temperature change of the panel itself lags behind the furnace temperature change due to heat capacity. This is taken into account when defining the sealing temperature profile.

[0003]

However, such a conventional sealing process employs a configuration in which two glass plates are bonded via a glass frit. There is a problem that the width W of the frame-shaped application region is required to be relatively large because the bonding strength is relatively weak, and that equipment costs are increased because the in-furnace process is employed.

The present invention has been made in view of the problems in this type of conventional bonding method, and an object thereof is to provide a method capable of instantly bonding a glass plate and a bonding object. Accordingly, for example, the two glass plates constituting the flat display panel can be easily, reliably and inexpensively bonded at low cost.

[0005]

In order to achieve the above object, a method of bonding a glass plate according to the present invention comprises the steps of: bonding a glass plate and a bonding object to each other with a material that absorbs a laser beam having a property of transmitting glass; By contacting the thin film through the glass plate by the laser beam and irradiating the thin film with the laser beam, the two objects sandwiching the thin film are welded by heat generated from the thin film. It is a feature.

Further, the bonding method according to the present invention as an embodiment is a bonding method of bonding glass plates for bonding two glass plates, which constitute a flat display panel, wherein the two glass plates are bonded. By adhering via a thin film made of a substance that absorbs laser light having a property of transmitting glass, the thin film is irradiated with the laser light and irradiating the thin film with the laser light in the adhered state. It is characterized in that the opposing surfaces of the two sandwiched glasses are welded by heat generated from the thin film.

As is apparent from the above two inventions, the bonding partner of the present invention is not necessarily limited to a glass plate. As another bonding partner, for example, a ceramic plate or the like can be cited. Further, as the laser light having a property of transmitting through glass, for example, a YAG laser light can be given. Examples of such a substance that absorbs laser light include Cr and various other metals. or,
As a form of the thin film, not only a metal foil can be used as it is, but also in the case of bonding two glass plates, it is also possible to adhere to one or both surfaces by vapor deposition or sputtering.
When irradiating a laser beam, the glass plate and the bonding partner must be in close contact with each other via the above-mentioned thin film. The meaning of this "adhesion" depends on the intensity of the laser beam, but generally, a gap of about 1 micron is not allowed.
In other words, it means the degree of adhesion to the extent that interference fringes appear. Otherwise, the energy gained from the laser light is
This is because the material is consumed in the kinetic energy of sputtering instead of raising the temperature. If necessary to secure this degree of adhesion, it is preferable to press the glass plate against the object to be bonded.

According to the present invention, the glass plate and the bonding object or the glass plates are welded by heat generated from the thin film interposed between the objects, so that the bonding strength is extremely high. Therefore, the width of the bonding region can be made smaller than that of the conventional one. Further, since the in-furnace process is not employed, the bonding operation can be completed in a very short time. Further, the irradiation light amount of the laser beam, and / or
Alternatively, the adhesive strength can be adjusted by controlling the irradiation trajectory. This laser beam irradiation can be easily performed using a scanning laser marker well known to those skilled in the art. In this case, as the irradiation trajectory, a wobbling or filling method that can locally concentrate energy can be adopted.

[0009]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

As described above, in the method for bonding a glass plate according to the present invention, the glass plate and the bonding partner are brought into close contact with each other via a thin film made of a substance that absorbs laser light having a property of transmitting glass. In the close contact state, the thin film is irradiated with the laser beam through the glass plate, whereby two objects sandwiching the thin film are welded by heat generated from the thin film.

One example of such a method of bonding glass plates is conceptually shown in the process diagram of FIG. Incidentally, in FIG.
Is a glass plate, 2 is a thin film, 3 is an adhesion partner, 4, 4 'is a laser beam, and 5 is a welded portion.

FIG. 1A shows the relationship between the glass plate 1 and the bonding counterpart 3 in a state before being brought into close contact. In this example, the thin film 2 made of a substance that absorbs laser light having a property of transmitting glass exists on the lower surface of the glass plate 1 as a coating. As a material of the thin film 2, for example, chromium (Cr) or an oxide thereof can be used. In addition, it is preferable that the surface of the bonding partner 3 is processed as smoothly as possible. This is to ensure a good degree of adhesion such that interference fringes are generated when both are superimposed.

In FIG. 1B, the glass plate 1 and the bonding partner 3 are separated by a laser beam 4 having a property of transmitting glass.
4 shows a state in which the thin film 2 is made in close contact with a thin film 2 made of a substance absorbing 4 ′. In this close contact state, the thin film 2
A slight gap (for example, a gap of about 1 μm depending on the intensity of the laser beam) between the substrate and the bonding partner 3 is not allowed.
If there is a gap, the energy given from the laser beam 4 is not used to raise the temperature of the thin film 2 but is used to scatter the thin film 2 and sputter it toward the bonding partner. . In this case, no welding action occurs. In this state, when the thin film 2 is irradiated with the laser beam 4 and transmitted through the glass plate 1, the thin film 2 existing at the irradiated portion is heated and instantaneously reaches the melting temperature of the glass plate 1 and the bonding partner 3. The laser beam 4 indicates the irradiation start position, and the laser beam 4 'indicates the irradiation end position after moving in the direction of the arrow.

FIG. 1C shows the bonding state between the glass plate 1 and the bonding counterpart 3 after the completion of the laser beam irradiation. At the portion irradiated with the laser beam, the high temperature generated from the thin film 2 completely melts the two substances sandwiching the thin film 2, and as a result, both are joined via the welded portion 5. That is, unlike the conventional bonding method using a glass frit, the glass plate 1 and the bonding partner 3 themselves, which are the materials to be bonded, are welded in a state of being mixed with each other, so that the bonding strength is extremely high. or,
The thickness and width of the welding portion 5 largely depend on the irradiation light amount of the laser beam 4 and the irradiation trajectory from the irradiation start position 4 to the irradiation end position 4 '. Therefore, the irradiation light amount of the laser light 4,
By controlling the irradiation locus and / or the irradiation locus, the adhesive strength can be arbitrarily adjusted.

Next, a description will be given of a method of bonding the glass plates for bonding the front and back glass plates constituting the flat display panel. In this example, a plasma display panel is employed as the flat display panel. In FIG. 2, reference numeral 6 denotes a front glass substrate constituting a plasma display panel, 7 denotes a rear glass substrate, and 8 denotes a laser absorbing coating formed on the inner surface of the front glass substrate 1 in a frame shape. The width W ′ of the laser absorbing film 8 is
The applied width W of the frit glass 103 shown in FIG.
Narrower than. When the adhesive strength is the same, for example, FIG.
In the case of (2), W = about 5 mm, whereas in the case of FIG. 2 of the present invention, W ′ = 1 to about 2 mm. The material of the laser absorbing film 8 is chromium (Cr)
Alternatively, an oxide thereof is employed. As a method for applying the laser absorbing film 8, a vacuum evaporation method, a sputtering method, or the like is employed.

The two glass substrates 6, 7 thus obtained
As shown in FIG. 3, are superimposed with the back glass substrate 7 facing upward, and positioned on a sample mounting table (not shown) of the scanning laser marker device 9. As is well known to those skilled in the art, the scanning laser marker 9
Is an apparatus capable of irradiating a laser beam while drawing an arbitrary trajectory on an object. In the figure, L1 is YA not shown.
Laser light arriving from the G laser oscillator, 91 is a reflecting mirror for directing the laser light L1 in the X direction, 92 is a reflecting mirror for directing the laser light arriving from the reflecting mirror 91 in the Y direction, and 93 is the reflecting mirror 91 in the direction of the arrow. A galvanometer scanner 94 for turning the reflection mirror 92 in the direction of the arrow; a laser beam 95 converging the laser light coming from the reflection mirror 92 and irradiating the rear substrate glass 7 as a sample with a predetermined spot diameter. Lens. Usually, this kind of laser marker 9 is
Teaching is possible using CAD data. Therefore, the positioning control of the irradiation position can be performed using the CAD data of the plasma display panel as it is. As the irradiation locus of the laser beam, it is preferable that the energy can be locally concentrated so that the thin film 8 is sufficiently heated. For example, a wobbling method or a filling method is preferable. FIG. 4 shows an example of an irradiation locus based on the wobbling method. As is clear from the figure, the wobbling method is an irradiation method in which the center of the irradiation spot 10 is turned in the direction of the arrow 11 while turning.
Although not shown, the filling method is to fill the irradiation target area with many parallel lines.

In this way, the two glass substrates 6 and 7 thus superimposed are irradiated with YAG laser light from the rear substrate 7 side.
When irradiated with a predetermined spot diameter and a predetermined scanning locus, the YAG laser light transmitted through the back glass substrate 7 is absorbed by the thin film 8. The thin film 8 is heated with a rise in temperature, and as a result, as described above with reference to FIG. 1C, the two glass plates 6 sandwiching the frame-shaped thin film 8 are interposed.
The surfaces of 7 melt instantaneously, mix with each other, and weld securely. At this time, by appropriately controlling the irradiation light amount and / or the irradiation trajectory of the laser beam, the adhesive strength can be appropriately adjusted.

As described above, when the present invention is used to bond two glass plates, which constitute a flat display panel, the bonding time can be reduced as compared with the conventional furnace process and the method using a bonding glass frit. And the adhesive strength can be improved. Since the adhesive strength is high, the width W ′ of the frame-shaped laser absorbing film 8 is
Since the image display area can be made narrower than that of the above, the image display area can be enlarged accordingly. Further, in the present invention, since an arbitrary bonding line can be easily formed by controlling the scanning trajectory of the laser beam, a lattice-shaped irradiation trajectory is adopted for the two glass plates constituting the flat display panel. By doing so, one glass substrate can be divided into a plurality of closed regions, and thereby a multi-display panel can be formed. The present invention can of course be applied to a liquid crystal display panel.

[0019]

As is apparent from the above description, according to the present invention, when applied to the bonding between a glass plate and an object to be bonded (for example, another object such as a glass plate or a ceramic plate), an adhesive is used. In addition, as compared with the conventional method employing an in-furnace process, the bonding time can be shortened and the bonding strength can be improved. If this is applied to the bonding of two glass plates forming a flat display panel, a frame can be obtained. The image display area can be enlarged by reducing the width of the shape adhesive area.

[Brief description of the drawings]

FIG. 1 is a process diagram for explaining a bonding method according to the present invention.

FIG. 2 shows the front and back sides of a flat display panel.
It is explanatory drawing which shows arrangement | positioning of a laser absorption coating in the case of applying this invention in order to adhere | attach two glass plates.

FIG. 3 shows the front and back sides of a flat display panel.
It is explanatory drawing which shows notionally the structure of the scanning type laser marker for adhering two glass plates.

FIG. 4 is an explanatory diagram showing an example of a laser irradiation locus by a scanning laser marker.

FIG. 5 is an explanatory diagram for explaining a conventional bonding method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass plate 2 Thin film 3 Adhesion partner 4, 4 'Laser beam 5 Welding part 6 Front glass substrate 7 Back glass substrate 8 Laser absorption film 9 Scanning laser marker 10 Irradiation spot 11 Arrow indicating spot moving direction 91 X direction reflection mirror 92 Y-direction reflecting mirror 93 Galvanometer 94 Galvanometer 95 Lens L1 Laser beam coming from YAG laser oscillator L2 Direction-controlled laser beam W, W 'Width of frame-shaped bonding region

Claims (5)

[Claims] 1. A glass plate and an object to be bonded are brought into close contact with each other via a thin film made of a substance that absorbs laser light having a property of transmitting glass, and in this state of adhesion, the glass light is transmitted through the glass plate by the laser light. Irradiating said thin film with said thin film so that two objects sandwiching said thin film are welded by heat generated from said thin film. 2. A method for bonding glass plates for bonding two glass plates, front and back, constituting a flat display panel, wherein the two glass plates absorb a laser beam having a property of transmitting glass. The laser light is transmitted through one of the glasses to irradiate the thin film, and the opposite surfaces of the two glasses sandwiching the thin film are brought into contact with the thin film. A method for bonding glass sheets, wherein the glass sheets are welded by heat generated from the glass sheet. 3. The method of claim 2, wherein the thin film is pre-applied to one or both surfaces of the two pieces of glass. 4. The method according to claim 1, wherein the laser light having a property of transmitting the glass is a YAG laser light. 5. The method according to claim 1, wherein the adhesive strength is adjusted by controlling an irradiation light amount and / or an irradiation trajectory of the laser light.