JP2022047865A - Device and method for workpiece bonding - Google Patents

Abstract

To provide a workpiece bonding device and a workpiece bonding method that can reduce air bubbles produced when bonding workpieces together, by realizing frame narrowing of an outer peripheral edge part of a product.SOLUTION: A workpiece bonding device 1 includes: a coating part 5 for coating an adhesive agent R generating adhesive force according to UV irradiation, on one surface of a workpiece W1, while moving relatively to the workpiece W1; an adhesive agent coating unit 2 having a UV irradiation part 6 for irradiating the coated adhesive agent R with ultraviolet light UV; and a workpiece bonding unit 3 for bonding the workpiece W1 which has been coated with the adhesive agent R and irradiated with ultraviolet light UV, and a workpiece W2 together. The UV irradiation part 6 irradiates the adhesive agent R with ultraviolet light UV, in a time zone before sagging 26 occurs on an outer peripheral edge part of the coated adhesive agent R from directly after starting to coat the adhesive agent R. In a workpiece bonding method, a product S is manufactured by bonding workpieces W1 and W2 together by using the workpiece bonding device 1.SELECTED DRAWING: Figure 1

Description

The present invention relates to a work bonding device and a work bonding method.

In order to bond a pair of workpieces that make up a display device such as a liquid crystal display, an adhesive that cures with ultraviolet rays is applied to the entire surface of one of the pair of workpieces, and the adhesive is applied from the start to the end. There is an adhesive supply device that irradiates the applied adhesive with ultraviolet rays to temporarily cure the adhesive (see, for example, Patent Document 1). The adhesive applied by such an adhesive supply device is temporarily cured, and the other work is bonded to the work through the adhesive, and the pair of bonded works is conveyed to the main cured portion and further applied to the adhesive. There is a work bonding device that cures the adhesive by irradiating it with ultraviolet rays or heating it (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2012-71281 Japanese Unexamined Patent Publication No. 2014-199457

However, in the adhesive supply device described in Patent Document 1 and the work bonding device described in Patent Document 2, the adhesive is irradiated with ultraviolet rays after an unspecified time elapses from the start to the end of application of the adhesive. It is temporarily cured. When the time from the start of application of the adhesive to the start of irradiation with ultraviolet rays is long (for example, 10 seconds or more), the adhesive flows to the surface of the work due to the wettability of the adhesive to the surface of the work, and the outer peripheral edge of the adhesive layer So-called "sagging" occurs, in which the shape of the

When the product after bonding is a display device such as a liquid crystal display, one work is a liquid crystal module, and the other is a cover glass, a light-shielding film (sometimes called a frame) is provided on the cover glass. Is common. Recently, there is a demand to make the line width of this light-shielding film as narrow as possible (sometimes called a narrow frame model), and if there is a sagging as described above, the end of the adhesive will be visible in the display area. In terms of appearance quality, there is a problem that a narrow frame model cannot be realized. Alternatively, the adhesive may squeeze out from the side surface of the liquid crystal display module due to the above-mentioned "drip".

Further, when the workpieces are bonded together, the adhesive presses the workpieces in a temporarily cured state. However, when the pressing force is removed while the adhesive is temporarily cured, the adhesive springs back to the thickness at the time of application, and the outer peripheral portion of the applied adhesive is pulled inward. This makes it even more disadvantageous for narrowing the frame. Further, in the main curing process after bonding, the light-shielding film may block ultraviolet rays, the curing rate of the adhesive below the light-shielding film may not increase, and the desired adhesive strength may not be obtained.

Further, when the workpieces are bonded together, visible bubbles may be caught and remain at the adhesive or the interface between the adhesive and the workpiece. When the product is a liquid crystal display or the like, good visibility and appearance quality cannot be obtained if visible bubbles remain. In Patent Document 1 and Patent Document 2, consideration for eliminating bubbles is not sufficient, and bubbles may remain.

Therefore, the present invention has been made to solve at least one of such problems, and it occurs when the outer peripheral edge of a product such as a liquid crystal display is narrowed and the workpieces are bonded together. It is an object of the present invention to provide a work bonding device and a work bonding method capable of reducing the number of bubbles to be formed and shortening the tact time.

[1] The work bonding device of the present invention is a work bonding device for bonding a pair of works via an adhesive, and is attached to one side of one of the pair of works and to the one of the works. An adhesive coating unit having a coating portion for applying the adhesive, which generates adhesive force by irradiation with ultraviolet rays while moving relative to each other, and an ultraviolet irradiation portion for irradiating the applied adhesive with ultraviolet rays, and the adhesive are applied. It also has a work bonding unit for bonding the one work and the other work irradiated with ultraviolet rays in a vacuum environment, and the ultraviolet irradiation portion is applied immediately after the start of application of the adhesive. It is characterized in that the adhesive is configured to irradiate ultraviolet rays at a time zone before the outer peripheral edge of the adhesive is sagging.

[2] In the work bonding device of the present invention, it is preferable that the ultraviolet irradiation unit is configured to collectively irradiate the entire coated surface of the adhesive with ultraviolet rays.

[3] In the work bonding device of the present invention, the ultraviolet irradiation portion applies ultraviolet rays to the adhesive applied while following the relative movement of the coating portion or by scanning after the application of the adhesive is completed. It is preferable that it is configured to irradiate.

[4] In the work bonding device of the present invention, the ultraviolet irradiation portion is exposed to ultraviolet rays in a time zone before the outer peripheral edge portion of the adhesive applied immediately after the start of application of the adhesive is sagging. It is preferable that the ultraviolet rays are further irradiated at least once after the irradiation.

[5] The work bonding device of the present invention is preferably configured so that the elapsed time from the start of application of the adhesive to the start of irradiation with ultraviolet rays is within 10 seconds.

[6] In the work bonding apparatus of the present invention, the coating portion responds to fluctuations in the coating film thickness from immediately after the start of coating of the adhesive until the coating film thickness of the adhesive stabilizes. It is preferable that the moving speed is increased or decreased with respect to the steady relative moving speed.

[7] In the work bonding device of the present invention, it is preferable that a light-shielding plate that blocks ultraviolet rays toward the nozzle tip portion of the coating portion is disposed between the coating portion and the ultraviolet irradiation portion. ..

[8] In the work bonding device of the present invention, a stage on which the one work is placed is arranged below the coating portion, and the stage is subjected to light reflection prevention treatment. preferable.

[9] In the work bonding device of the present invention, the work bonding unit has a pressing mechanism that presses the pair of workpieces in a stacked state via the adhesive irradiated with ultraviolet rays, and the pair of workpieces. And it is preferable to have a vacuum chamber for accommodating the pressing mechanism.

[10] In the work bonding device of the present invention, when the one work and the other work are bonded by the work bonding unit, the vacuum degree of the vacuum chamber is configured to be 100 Pa or less. It is preferable that it is.

[11] In the work bonding device of the present invention, when the one work and the other work are bonded by the work bonding unit, the pressing force applied to the pair of works by the pressing mechanism is applied. It is preferably configured to be 0.5 N / cm2 or more and 5 N / cm2 or less.

[12] In the work bonding device of the present invention, the pair of bonded works are accommodated, the internal pressure is controlled to 0.2 MPa or more and 0.7 MPa or less, and the internal temperature is controlled to room temperature or more and 80 ° C. or less. It is preferable to have an autoclave to be used.

[13] In the work bonding method of the present invention, the work bonding device according to any one of [1] to [12] above is used, and the pair of works are bonded via the adhesive. The method is a coating step of applying the adhesive whose adhesive force is generated by irradiation with ultraviolet rays to one side of the one work while moving relative to the one work, and application immediately after the start of application of the adhesive. An ultraviolet irradiation step of irradiating the applied adhesive with ultraviolet rays during a time period before the outer peripheral edge of the adhesive drips, and one of the workpieces irradiated with ultraviolet rays and the other. It is characterized by including a step of bonding a work and a work in the vacuum chamber.

[14] In the work bonding method of the present invention, it is preferable to collectively irradiate the entire coated surface of the adhesive with ultraviolet rays in the ultraviolet irradiation step.

[15] In the work bonding method of the present invention, in the ultraviolet irradiation step, it is preferable to irradiate the applied adhesive with ultraviolet rays while following the relative movement of the coated portion.

[16] In the work bonding method of the present invention, the adhesive is applied immediately after the start of application of the adhesive and before the outer peripheral edge of the adhesive is sagging. It is preferable to irradiate the subject with ultraviolet rays and then irradiate the ultraviolet rays at least once.

[17] In the work bonding method of the present invention, the pair of bonded works is conveyed to an autoclave, and the internal pressure of the autoclave is 0.2 MPa or more and 0.7 MPa or less, and the internal temperature is room temperature or more. It is preferable to further have an autoclave step of holding the temperature at 80 ° C. or lower for a predetermined time.

Here, the above-mentioned "drip" refers to a state in which the shape of the outer peripheral edge portion of the adhesive is deformed due to the adhesive flowing to the contact surface with the work to be applied due to the wettability to the work surface after the adhesive is applied. ..

According to the work bonding device and the work bonding method of the present invention, by irradiating ultraviolet rays in a time zone before dripping occurs on the outer peripheral edge portion of the adhesive applied immediately after the start of adhesive application. , It is possible to cure the adhesive to prevent the occurrence of sagging, and to realize a narrow frame on the outer peripheral edge when the product is a display device such as a liquid crystal display. Further, by setting the degree of vacuum in the vacuum chamber to 100 Pa or less at the time of bonding the workpieces and setting the load applied to the pair of workpieces by the pressing mechanism to 0.5 N / cm2 or more and 5 N / cm2 or less, it is generated when the workpieces are bonded. It is possible to reduce the number of visible bubbles. Further, in the autoclave, the pair of bonded workpieces are pressurized at an internal pressure of 0.2 MPa or more and 0.7 MPa or less, and heated to room temperature or more and 80 ° C. or less to further reduce visible bubbles. It becomes possible. Further, the work bonding device has an adhesive coating unit, a work bonding unit, and an autoclave, and the adhesive application, ultraviolet irradiation, work bonding, and autoclave processing are performed in each unit, so that the tact time is shortened. It becomes possible.

It is explanatory drawing which shows the schematic structure of the work bonding apparatus 1. It is a block diagram which shows the schematic structure of the adhesive application unit 2A which concerns on 1st example. It is a block diagram which shows the schematic structure of the adhesive application unit 2B which concerns on 2nd example. It is a perspective view which shows the situation which the ultraviolet ray irradiation part 6B irradiates an ultraviolet ray UV while the coating part 5 applies the adhesive R to the work W1. It is explanatory drawing which shows the schematic structure of the work bonding unit 3, and is the explanatory view which shows the situation which the work W2 was supplied to the work bonding unit 3. It shows the situation where the work W1 and the work W2 are attached. It is explanatory drawing which shows the schematic structure of the autoclave 4. It is a process flow diagram which shows the main process of the work bonding method. It is a graph which shows the relationship between the elapsed time T from the start of application of adhesive R, and the sagging width G. It is explanatory drawing explaining the relationship between the ultraviolet irradiation and the curing rate of adhesive R. It is explanatory drawing explaining the behavior of the adhesive R from the ultraviolet irradiation process to the work bonding process. It is a figure explaining the relationship between the coating thickness of adhesive R and the adhesive coating speed. It is a figure which shows the relationship between the total area of visible bubbles in a bonding process, and the degree of vacuum of a vacuum chamber 20. It is explanatory drawing which shows the relationship between the pressing force applied to the work W1 and the work W2, and the total visible bubble area. It is explanatory drawing which shows the bubble | bubble disappearing effect by an autoclave 4.

Hereinafter, the work bonding device 1 according to the embodiment of the present invention and the work bonding method using the work bonding device 1 will be described with reference to the drawings. It should be noted that each configuration diagram described below is a schematic diagram that does not strictly reflect the actual structure.

[Structure of work bonding device 1]
FIG. 1 is an explanatory diagram showing a schematic configuration of a work bonding device 1. In the following description, the works W1 and W2 are not particularly limited, but one of the pair of works to be attached is the liquid crystal module, the other work W2 is the cover glass, and after bonding. The product S of the above will be described as a liquid crystal display. The work bonding device 1 includes an adhesive coating unit 2 and a work W1 having an coating unit 5 for applying the adhesive R to the work W1 in a planar manner and an ultraviolet irradiation unit 6 for irradiating the applied adhesive R with ultraviolet UV rays. It is composed of a work bonding unit 3 for bonding the work W2 and the work W2 via an adhesive R, and an autoclave 4 that pressurizes and heats a product S in which the work W1 and the work W2 are bonded. The ultraviolet irradiation unit 6 is a general term including the ultraviolet irradiation unit 6A (see FIG. 2) and the ultraviolet irradiation unit 6B (see FIG. 3), which will be described below.

The work bonding device 1 is a transport device 7A that feeds the work W1 to the adhesive coating unit 2, and a transport device 7B that feeds the work W1 coated with the adhesive from the adhesive coating unit 2 to the work bonding unit 3. , The transport device 7C for supplying the work W2 to the work bonding unit 3, the transport device 7D for supplying the product S obtained by bonding the work W1 and the work W2 from the work bonding unit 3 to the autoclave 4, and the autoclave 4. It has a transport device 7E that removes the product S from the material. As the transport devices 7A to 7E, it is possible to use a transport device, a robot device, or a transport device in which they are combined.

The adhesive R used in the present embodiment is a liquid in a normal state, has excellent light transmittance, and is adhesive when irradiated with ultraviolet UV rays, and is photocurable adhesive. It is called an agent. Adhesive R can obtain sufficient adhesive strength by irradiating ultraviolet UV with appropriate light energy and pressing the work W1 and the work W2 on top of each other when the curing rate reaches 90% or more. It is to become. Subsequently, each configuration of the adhesive application unit 2, the work bonding unit 3, and the autoclave 4 will be described with reference to the drawings.

[Structure of Adhesive Coating Unit 2A]
FIG. 2 is a configuration explanatory view showing a schematic configuration of the adhesive coating unit 2A according to the first example. FIG. 2 shows one situation in which the adhesive R applied to the entire surface of the work W1 is irradiated with ultraviolet UV rays. The adhesive coating unit 2A according to the first example has a coating portion 5 for applying the adhesive R to one side (upper surface) of the work W1 while the work W1 is placed on the stage 8, and the applied adhesive R. It has an ultraviolet irradiation unit 6A that irradiates ultraviolet UV. The coating portion 5 is connected to a storage tank 9 for storing the liquid adhesive R via a pump P.

The arrow shown in FIG. 2 indicates the moving direction of the coating portion 5 with respect to the work W1. Since the work W1 can be fixed and the coating portion 5 can be moved in the direction of the arrow, and the coating portion 5 can be fixed and the work W1 can be moved in the opposite direction of the arrow. Or the relative movement direction.

In the first example shown in FIG. 2, after the adhesive R is applied to the entire surface of the work W1 while moving the coating portion 5 in the direction of the arrow, the ultraviolet irradiation unit 6A collectively irradiates the entire coated surface of the adhesive R with ultraviolet UV rays. This is an example of The coating unit 5 includes a nozzle 10 that discharges the adhesive R to the work W1. The coating portion 5 of this example is a slit coater having a slit-shaped nozzle 10 orthogonal to the moving direction. The ultraviolet irradiation unit 6A is a so-called surface irradiation method capable of collectively irradiating the entire coated surface of the adhesive R with ultraviolet UV rays.

Although not shown, the coating unit 5 includes a Z-axis drive mechanism for moving the nozzle 10 toward and away from the work W1 and an X-axis drive mechanism for moving the nozzle 10 in the direction of the arrow. It is also possible to fix the coating unit 5 and move the stage 8 (work W1). In such a configuration, for example, the coating unit 5 is provided with a Z-axis drive mechanism.

A substantially L-shaped light-shielding plate 11 is arranged between the coating unit 5 and the ultraviolet irradiation unit 6A at a position close to the ultraviolet irradiation unit 6A. When the ejection port of the nozzle 10 is irradiated with ultraviolet UV rays, the adhesive R may become sticky and clog the nozzle 10. The light-shielding plate 11 prevents the ultraviolet UV emitted from the ultraviolet irradiation unit 6 from directly irradiating the ejection port of the nozzle 10. The light-shielding plate 11 may be a simple plate-shaped member, but the light-shielding effect can be enhanced by forming the light-shielding plate 11 into an L-shape. The light-shielding plate 11 is interlocked with the coating portion 5.

The work mounting surface 8a of the stage 8 is subjected to a light reflection prevention treatment such as black coating. The light reflection prevention treatment is performed in order to prevent clogging due to ultraviolet UV rays reflected by the work mounting surface 8a and irradiating the adhesive R at the ejection port of the nozzle 10. For the same purpose, it is more preferable to apply the light reflection prevention treatment to the other constituent members arranged around the coating portion 5 and the ultraviolet irradiation portion 6 in addition to the stage 8.

The ultraviolet irradiation unit 6A follows the coating unit 5 and moves in the direction of the arrow, stops above the work W1 and irradiates the ultraviolet UV. Alternatively, after the adhesive is applied, the ultraviolet irradiation unit 6A can be lowered from a height position that does not hinder the movement of the coating unit 5 to irradiate the ultraviolet UV. Alternatively, it is also possible to fix the ultraviolet irradiation unit 6A above the coating portion at a position above the work W1 to irradiate the ultraviolet UV.

[Structure of Adhesive Coating Unit 2B]
FIG. 3 is a configuration explanatory view showing a schematic configuration of the adhesive coating unit 2B according to the second example. FIG. 3 shows one situation in which the work W1 is irradiated with ultraviolet rays while being coated with the adhesive R. The adhesive coating unit 2B has a coating unit 5 for applying the adhesive R to one side of the work W1 and an ultraviolet irradiation unit 6B for irradiating the applied adhesive R with ultraviolet UV rays. The coating portion 5 is connected to a storage tank 9 for storing the adhesive R via a pump P.

The arrows shown in FIG. 3 indicate the relative moving directions of the coating unit 5 and the ultraviolet irradiation unit 6B with respect to the work W1. The ultraviolet irradiation unit 6B is arranged on the rear side with respect to the relative moving direction of the coating unit 5. The ultraviolet irradiation unit 6B is a so-called line irradiation method capable of irradiating ultraviolet UV with a width wider than the slit width of the nozzle 10. It is also possible to fix the coating portion 5 and move the stage 8 (work W1).

The ultraviolet irradiation unit 6B moves following the movement of the coating unit 5. Note that the follow-up means that the ultraviolet irradiation unit 6B moves in the same direction while the coating unit 5 is moving, and the movement speed of the ultraviolet irradiation unit 6B is not always the same as the movement speed of the coating unit 5. do not have. The ultraviolet irradiation unit 6B is controlled to move at a speed at which the adhesive R can be irradiated with ultraviolet UV having a predetermined light energy. If the adhesive application is completed before the sagging occurs, the ultraviolet irradiation unit 6B may be scanned on the coated adhesive R after the application is completed. In addition, "before the occurrence of sagging" is not limited to the fact that sagging does not occur at all, and includes a state in which the sagging width G (see FIG. 9) is 1 mm or less.

A substantially L-shaped light-shielding plate 11 is arranged between the coating portion 5 and the ultraviolet irradiation portion 6. The ultraviolet shielding function of the light-shielding plate 11 is the same as that of the first example, and is configured to be interlocked with either the coating unit 5 or the ultraviolet irradiation unit 6. That is, the adhesive coating unit 2B has the same configuration as the adhesive coating unit 2A described in the first example except for the configuration and operation of the ultraviolet irradiation unit 6B. The operation and control of the ultraviolet irradiation units 6A and 6B will be described with reference to FIGS. 8 to 11.

FIG. 4 is a perspective view showing a situation in which the ultraviolet irradiation unit 6B irradiates the ultraviolet UV while the coating unit 5 applies the adhesive R to the work W1. The coating unit 5 coats the adhesive R on the upper surface of the work W1 in a planar direction while moving in the direction of the arrow, and the ultraviolet irradiation unit 6B irradiates the upper surface of the work W1 with ultraviolet UV at a predetermined time interval D. Move in the direction. The adhesive R has a high adhesiveness (curing rate) from the position where the ultraviolet UV is irradiated. Subsequently, the configuration and operation of the work bonding unit 3 will be described with reference to FIGS. 5 and 6.

[Structure of work bonding unit 3]
FIG. 5 is an explanatory diagram showing a schematic configuration of the work bonding unit 3, and shows a situation in which the work W1 and the work W2 are supplied to the work bonding unit 3. FIG. 6 is an explanatory diagram showing a situation in which the work W1 and the work W2 are attached. The work bonding unit 3 includes a stage 12 on which the work W1 coated with the adhesive R and irradiated with ultraviolet rays UV is placed, and a pressing mechanism 16 for pressing the work W2 against the work W1.

The pressing mechanism 16 includes a suction plate 17 that sucks and holds one side of the work W2, a drive mechanism 18 that raises and lowers the suction plate 17, and an alignment mechanism (not shown) that aligns the positions of the work W1 and the work W2. .. By lowering the suction plate 17 in a state where the work W2 is sucked, the work W2 can be attached to the work W1. As shown in FIG. 5, the work bonding unit 3 has a housing 19 that covers the work W1 and the pressing mechanism 16. The vacuum chamber 20 is configured by bringing the housing 19 into close contact with the stage 12. The housing 19 is retracted to a position where the materials for the works W1 and W2 and the materials for the works W1 and W2 (manufactured product S) after bonding are not hindered. Next, the bonding of the work W1 and the work W2 will be described.

As shown in FIG. 6, first, the housing 19 is lowered to form the vacuum chamber 20, the inside of the vacuum chamber 20 is set to an environment lower than the atmospheric pressure, then the suction plate 17 is lowered, and the work W2 is placed on the work W1. to paste together. The housing 19 is provided with a vacuum device (not shown) and a pipe connected to the vacuum device. The vacuum chamber 20 may be configured by the base plate (not shown) for fixing the stage 12 and the housing 19. The reason why the work W1 and the work W2 are bonded inside the vacuum chamber 20 is that the air bubbles entrained by the adhesive R at the time of bonding are discharged. Subsequently, the configuration of the autoclave 4 will be described with reference to FIG. 7.

[Configuration of autoclave 4]
FIG. 7 is an explanatory diagram showing a schematic configuration of the autoclave 4. The autoclave 4 is composed of a stage 15 on which a product (liquid crystal display) S composed of the bonded work W1 and the work W2 is placed, and a housing 21 that covers the product S. The housing 21 is retracted to a position where there is no problem when supplying or removing the material S of the product S. The autoclave 4 is provided to form a closed space by bringing the housing 21 into close contact with the stage 15, and to reduce or eliminate air bubbles by holding the closed space at a high pressure and a high temperature.

Note that FIG. 7 shows an example in which one product S is housed in the autoclave 4. This is to make the volume of the autoclave 4 as small as possible so that the inside of the autoclave 4 can quickly reach a predetermined pressure and temperature after feeding the product S. It is also possible to put a large number of products S in the autoclave 4 and shorten the tact time for each product by batch processing. Whether to store the products S one by one in the autoclave 4 or to perform batch processing depends on the processing time of the autoclave 4 for each tact time of the adhesive application units 2A and 2B and the work bonding unit 3. Judge whether it is possible to keep it at the same level. The pressure condition and the temperature condition in the autoclave 4 will be described with reference to FIG. Subsequently, the work bonding method and the control conditions in each process will be described.

[Work bonding method]
FIG. 8 is a process flow chart showing a main process of the work bonding method. First, the work bonding device 1 is started, and the work W1 (liquid crystal module in this example) is supplied to the adhesive coating unit 2A (or the adhesive coating unit 2B) by the transport device 7A (step S1). When the adhesive coating unit 2A of the first example is used, the adhesive R is applied to the work W1 by the coating portion 5 (step S2), and the entire surface of the applied adhesive R is coated with ultraviolet UV rays by the ultraviolet irradiation unit 6A. (Step S3), and the process proceeds to step S5.

When the adhesive coating unit 2B is used, ultraviolet rays are applied to the adhesive R applied while the adhesive R is applied to the work W1 by the coating portion 5 (step S2) and the ultraviolet irradiation portion 6B is made to follow the coating portion 5. Irradiate with UV (step S3). When the adhesive coating unit 2B is used, it is irradiated with ultraviolet rays and UV rays a plurality of times. The first irradiation of ultraviolet rays UV is performed within a predetermined elapsed time from the start of application of the adhesive R. The predetermined elapsed time zone is the time from immediately after the start of application of the adhesive to the occurrence of sagging 26 in the applied adhesive R, and in this example, the elapsed time from the start of application of the adhesive R is 10. Within seconds. The first ultraviolet irradiation is a step of suppressing the occurrence of sagging of the adhesive R, and the reason for setting the adhesive R within 10 seconds will be described later with reference to FIGS. 9 to 11. When the time from the start of application of the adhesive R to the end of application is 10 seconds or more (for example, when the work W1 has a large size or when the adhesive R is applied at a low speed), the coating portion 5 is moved (adhesion). The ultraviolet irradiation unit 6B is moved within 10 seconds for the agent application). If the application is completed within 10 seconds from the start of the adhesive application, the ultraviolet irradiation unit 6B is scanned after the adhesive application is completed to perform ultraviolet irradiation.

Subsequently, the second and subsequent ultraviolet irradiations are performed (step S4). Since the second and subsequent ultraviolet irradiations suppress the occurrence of sagging by the first ultraviolet irradiation, the ultraviolet irradiation can be started at an arbitrary timing and the ultraviolet irradiation unit 6B can be moved at an arbitrary moving speed. Is. The second and subsequent UV irradiations are repeated until the adhesive R reaches a predetermined curing rate (for example, a curing rate of 90% or more). The number of times of ultraviolet irradiation is set based on the cumulative light energy of ultraviolet irradiation and the curing rate of the adhesive R. By setting the curing rate to 90% or more, it is possible to obtain sufficient adhesive strength between the work W1 and the work W2.

In the second and subsequent ultraviolet irradiations, the ultraviolet irradiation unit 6B may perform ultraviolet irradiation while moving from the position where the first irradiation ends to the position where the ultraviolet irradiation starts, and at the position where the first ultraviolet irradiation starts. After returning, ultraviolet irradiation may be performed. Alternatively, the ultraviolet irradiation may be repeated while reciprocating the ultraviolet irradiation unit 6B. Further, for the second and subsequent ultraviolet irradiations, an ultraviolet irradiation unit may be added between the adhesive coating unit 2B and the work bonding unit 3.

After irradiation with ultraviolet rays (after steps S3 and S4), the work W1 and the work W2 (in this example, the work W2 is a cover glass) are supplied to the work bonding unit 3 by the transfer devices 7B and 7C (step S5). Each step of step S1 to step S4 is performed at room temperature (for example, 15 ° C. to 25 ° C.) and in an atmospheric pressure environment. The work W1 is supplied from the adhesive coating unit 2 onto the stage 8 by the transport device 7B. On the other hand, the work W2 is fed from a work stocker (not shown) to the suction plate 17 by the transfer device 7C, and is sucked and held by the suction plate 17.

When each of the work W1 and the work W2 is held as described above, the housing 19 is lowered to reduce the pressure inside the vacuum chamber 20 to a vacuum degree of 100 Pa or less (step S6). The temperature at this time is room temperature. Next, the pressing mechanism 16 is driven, the work W1 and the work W2 are overlapped and pressed, and the work W1 and the work W2 are bonded to each other via the adhesive R (step S7). The pressing force shall be 0.5 N / cm ² or more and 5 N / cm ² or less. The pressing force is of a magnitude necessary to secure the adhesive strength between the work W1 and the work W2 and to reduce the bubbles generated at the interface between the adhesive R and the work W2 at the time of bonding. The relationship between the pressing force and the bubbles will be described with reference to FIG. Next, the product S in which the work W1 and the work W2 are bonded is conveyed to the autoclave 4 to perform defoaming treatment.

When the bonding between the work W1 and the work W2 is completed, the housing 19 is retracted, and the product S is transported from the bonding device 3 to the autoclave 4 by the transport device 7D (step S8). Then, after lowering the housing 21, a high pressure and a high temperature are applied to the product S (step S9). The pressure inside the autoclave 4 is controlled to 0.2 Mp or more and 0.7 Mp or less, and the internal temperature is controlled to room temperature or more and 80 ° C. or less. (Step S10). The predetermined time here is preferably the tact time of the adhesive application unit 2 and the work bonding unit 3. The relationship between the environment in the autoclave 4 and the bubbles will be described with reference to FIG.

In the adhesive application unit 2, the work bonding unit 3, and the autoclave 4,
In order to suppress the occurrence of sagging 26 and realize a narrow frame, and to reduce the visible bubbles generated when the workpieces are bonded, it is necessary to appropriately control each unit. This will be described below.

First, the adhesive coating unit 2 will be described with reference to it. An example will be described in which the product S is a liquid crystal display, the work W1 is a liquid crystal module, and the work W2 is a cover glass. In a liquid crystal display, it is common to provide a light-shielding film 25 (see FIG. 11) in a frame shape on four sides around the screen. The light-shielding film 25 is provided on the surface of the work W2 facing the work W1 by printing or a thin plate frame. In a liquid crystal display, there is a demand for a so-called narrow frame, in which the width of the light-shielding film 25 is narrowed.

The adhesive R develops adhesiveness (increases the curing rate) by irradiating with ultraviolet UV rays, is called a photocurable adhesive, and is a liquid when applied. Adhesive R causes sagging 26 when the time from application to irradiation with ultraviolet rays becomes long (see FIG. 9). Since there is a time lag between the time immediately after the adhesive R is applied and the time when the dripping 26 occurs, the surface of the adhesive R should be at least cured (increased the adhesiveness) by irradiating with ultraviolet UV rays before the dripping 26 occurs. This makes it possible to suppress the sagging width G (see FIG. 9).

FIG. 9 is a graph showing the relationship between the elapsed time from the start of application of the adhesive R and the sagging width G. FIG. 9 is a semi-logarithmic graph in which the horizontal axis is the elapsed time (seconds), the vertical axis is the sagging width G (mm), and the elapsed time T is a logarithmic display. In FIG. 9, the shape shown by the dotted line shows the shape of the adhesive R immediately after the start of the adhesive application. As shown in the graph of FIG. 9, when the ultraviolet UV is not irradiated, the sagging width G increases as the elapsed time increases. When the thickness of the coated cloth of the adhesive R is 450 μm and the elapsed time is 10 seconds or less, the sagging width G can be suppressed to 1 mm or less. In the case of the conventional adhesive application method in which the elapsed time is not specified, for example, when the elapsed time is 40 seconds, the sagging width G is 2 mm, and when the elapsed time T is 120 seconds, the sagging width G is 2.5 mm. ..

If the distance from the end of the work W1 to the adhesive application start position is short, the adhesive R may flow out to the side surface of the work W1. It is possible to eliminate the occurrence of sagging 26 by irradiating the ultraviolet UV immediately after the start of the adhesive application, but since it is difficult due to the device configuration, from immediately after the start of the adhesive R application to the start of the ultraviolet UV irradiation. By setting the elapsed time to 10 seconds or less, it is possible to realize a narrow frame. In order to obtain the desired adhesive strength between the work W1 and the work W2, ultraviolet irradiation is performed a plurality of times. This will be described with reference to FIG.

FIG. 10 is an explanatory diagram illustrating the relationship between ultraviolet irradiation and the curing rate of the adhesive R. The horizontal axis represents time and the vertical axis represents the curing rate (%). The curing rate is a result measured by the FT-IR method (Fourier Transform Infrared Spectroscopy). When the adhesive R is irradiated with ultraviolet UV rays, the curing rate increases as the irradiation time elapses. When the rated output of the ultraviolet irradiation units 6A and 6B is 1,000 mW / cm ² , the light energy becomes 2,000 mJ / cm ² if the first ultraviolet irradiation time t1 is 2 seconds, and the adhesion at this time is achieved. The surface hardening rate of the agent R is 20%. If the surface hardening rate is 20%, it is possible to suppress the occurrence of sagging 26. However, when the work W1 and the work W2 are bonded together with the surface hardening rate of 20%, the bonding strength is insufficient. Therefore, the second ultraviolet irradiation is performed.

In the second ultraviolet irradiation, if the rated output of the ultraviolet irradiation unit 6B is 1,000 mW / cm ² and the ultraviolet irradiation time t2 is 10 seconds, the light energy is 10,000 mJ / cm ² . That is, the adhesive R has been given a cumulative light energy of 12,000 mJ / cm ² from the start of ultraviolet irradiation. At this time, the curing rate on the surface and inside of the adhesive R is 90% or more, and it is possible to secure the bonding strength. The time t3 between the first ultraviolet irradiation and the second ultraviolet irradiation is not particularly limited. That is, the second ultraviolet irradiation may be performed immediately after the first ultraviolet irradiation. If the time required for the second UV irradiation is longer than the tact time for bonding the workpieces, the adhesive coating unit 2 and the workpiece bonding unit 3 shown in FIG. 1 are used to shorten the tact time. An ultraviolet irradiation unit (not shown) is placed between and. Assuming that the curing rate of the adhesive surface is 20% in the first ultraviolet irradiation, the surface shape collapses and sagging 26 occurs in about 2 hours after the ultraviolet irradiation, so that the second time is within 2 hours, preferably within 1 hour. Irradiate with ultraviolet rays.

In the case of batch purple irradiation according to the first example, if there is a time during which 12,000 mJ of light energy can be applied to the adhesive R after the start of ultraviolet UV irradiation, ultraviolet irradiation is performed once. Just do it. In the first example, when the time required for the first ultraviolet irradiation is longer than the tact time of bonding the workpieces, the adhesive coating unit 2 shown in FIG. 1 is used to shorten the tact time. An ultraviolet irradiation unit (not shown) is arranged between the work bonding unit 3 and the work bonding unit 3. If a light source having a rated output of the ultraviolet irradiation unit 6A larger than 1,000 mW / cm ² appears, the ultraviolet irradiation time can be shortened.

In the second example, when the cumulative light energy of 12,000 mJ / cm ² cannot be given in the second ultraviolet irradiation, the number of ultraviolet irradiations is increased to 3 or 4 times. The rated output of the ultraviolet irradiation unit 6B in this example is 1,000 mW / cm ² , but if the rated output can be set to 1,000 mW / cm ² or more, for example, 1,200 mW / cm ² , the irradiation time is 10 seconds. It is possible to make the entire curing rate including the surface of the adhesive R 90% or more.

The factor that hinders the narrowing of the frame is the sagging that directly occurs when the adhesive is applied, but it also exists as an indirect factor when the work W1 and the work W2 are bonded together. This will be described with reference to FIG.

FIG. 11 is an explanatory diagram illustrating the behavior of the adhesive R from the ultraviolet irradiation step to the work bonding step. The vertical (i) column of FIG. 11 shows a conventional example in which ultraviolet irradiation is started 40 seconds after the adhesive is applied, and the vertical (ii) column of FIG. 11 is within 10 seconds immediately after the adhesive is applied. An example of starting ultraviolet irradiation is shown. FIG. 11 exaggerates the thickness of the adhesive R. Column (i) and column (ii) will be compared and described (see also FIG. 9). In columns (i) and (ii), (a) represents immediately after the start of application of the adhesive R, (b) represents after the adhesive R is irradiated with ultraviolet UV rays, and (c) represents the work. It shows the situation where W1 and the work W2 are bonded together and a pressing force is applied. As shown in (a), immediately after the application of the adhesive R, the shape of the end portion of the adhesive R is substantially vertical because no sagging 26 has occurred or the sagging width is very small.

In the example shown in FIG. 11, the work W1 is a liquid crystal module, the work W2 is a cover glass, and the product S is a liquid crystal display. This is an example provided. The light-shielding films 25A and 25B have the same position and the same width in the row (i) and the row (ii).

As shown in (b), when a certain time elapses after the application of the adhesive R, a sagging 26 is generated at the end portion of the adhesive R. The row (i) is an example in which ultraviolet UV is irradiated 40 seconds after the adhesive is applied, and the sagging width G1 is about 2 mm. The row (ii) is an example in which ultraviolet UV is irradiated within 10 seconds immediately after the adhesive is applied, and the sagging width G2 is about 1 mm. After irradiation with ultraviolet rays, a convex portion 27 is generated at the end portion of the adhesive R with the surface tension of the adhesive R and the curing shrinkage due to the ultraviolet rays. When the curing rate of the adhesive R becomes 90% or more by irradiation with ultraviolet rays UV, the works W1 and W2 are bonded together.

As shown in (c), when the work W1 and the work W2 are bonded together, in the row (i), the sagging 26 is visible inside the light-shielding film 25B provided on the work W2. In order to make the sagging 26 invisible, the width of the light-shielding film 25B must be widened to a width in which the sagging 26 cannot be seen, and it is not possible to realize a narrow frame. On the other hand, in the (ii) row, the sagging 26 is within the forming range of the light-shielding film 25B and cannot be visually recognized from above.

Even if the relative moving speed of the coating portion 5 is constant, the coating thickness of the coating portion 5 tends to be thin within a certain distance range immediately after the start of coating of the adhesive R. If the coating thickness becomes non-uniform, it may not be possible to control the sagging width G even if the elapsed time from the start of adhesive application to the start of ultraviolet irradiation is controlled. Therefore, it is necessary to control the coating thickness of the adhesive R so as to be stable immediately after the start of the adhesive coating. This will be described with reference to FIG.

FIG. 12 is a diagram illustrating the relationship between the coating thickness of the adhesive R and the adhesive coating speed. FIG. 12 (a) is a graph showing an example of a change in the coating thickness (μm) of the adhesive when the coating speed of the adhesive R (moving speed of the coating portion 5) is constant, and is a graph of FIG. 12 (b). ) Is a diagram showing the coating thickness when the coating speed of the adhesive R of the coating portion 5 is changed. The horizontal axis indicates the coating distance (mm) from the coating start position of the adhesive R. Note that FIG. 12 shows an example in which the coating speed is 20 mm / sec and the target coating thickness is 450 μm. As shown in FIG. 12A, in the range of about 20 mm from the start of application of the adhesive R, it takes a certain time until the internal pressure of the coating portion 5 becomes constant, so that the coating is applied even if the coating speed is constant. Immediately after the start, the coating thickness is thin and gradually increases, and when the coating distance reaches about 20 mm, the target coating thickness becomes 450 μm, and then the coating thickness stabilizes at 450 μm.

Therefore, in order to stabilize the coating thickness immediately after the start of coating of the adhesive R, the coating speed is controlled. As shown in FIG. 12B, the coating speed is gradually switched within a range of about 20 mm in which the coating thickness is stable immediately after the start of coating of the adhesive R. Immediately after the start of coating with a thin coating thickness, the coating speed is slowed down, and as the coating speed approaches the target 450 μm, the coating speed is approached to 20 mm / sec. By controlling the coating speed in this way, it is possible to stabilize the coating thickness of the adhesive R from the start to the end of coating to 450 μm.

The thickness immediately after the start of application of the adhesive R is affected by physical properties such as the viscosity of the adhesive R, the surface condition of the work W1, and the target application thickness. Therefore, the switching condition of the coating speed is set after grasping the tendency of the change in the adhesive coating thickness in advance by preliminary operation or the like. When the thickness after the start of coating becomes thicker than the target coating thickness, it is possible to control the coating speed to be gradually reduced.

Subsequently, the conditions of the bonding step (step S7) in the work bonding unit 3 will be described with reference to FIG. When the product S is a liquid crystal display, the work W1 is a liquid crystal module, and the work W2 is a cover glass, the applied adhesive R and visible air bubbles between the adhesive R and the work W2 are present. The visibility and appearance quality of the display are impaired. The bubbles include those originally contained in the adhesive R, those that are involved in the coating process, and those that are involved in the bonding. However, the visible bubbles were dominated by those caught during bonding. Therefore, a defoaming means for discharging bubbles or making them invisible in the bonding step will be described. As described above, the bonding step (step S7) is performed inside the vacuum chamber 20.

FIG. 13 is a diagram showing the relationship between the total area of visible bubbles in the bonding step and the degree of vacuum of the vacuum chamber 20. The horizontal axis shows the degree of vacuum (Pa), and the vertical axis shows the tendency of the total area of visible bubbles to occur. The total area of bubbles is visually determined to be large or small. As shown in FIG. 13, when the degree of vacuum is 100 Pa or less, the total area of bubbles tends to decrease significantly. Therefore, if the degree of vacuum in the vacuum chamber 20 is controlled to 100 Pa or less when the work W1 is attached to the work W2, it is possible to suppress the generation of visible bubbles in a liquid crystal display or the like.

Further, as a means for removing visible bubbles, in addition to controlling the degree of vacuum as described above, the magnitude of the pressing force (load) applied to the work W1 and the work W2 by the pressing mechanism 16 is appropriately controlled. It was confirmed that it was also effective. This will be described with reference to FIG.

FIG. 14 is an explanatory diagram showing the relationship between the pressing force applied to the work W1 and the work W2 and the total visible bubble area. In FIG. 14, the horizontal axis represents the pressing force (N / cm ² ), and the vertical axis represents the tendency of the total area of visible bubbles to be generated. The total area of bubbles is visually determined to be large or small. As shown in FIG. 14, the larger the pressing force, the smaller the total area of visible bubbles tends to be, and when the pressing force is 0.5 N / cm ² or more, the total area becomes smaller. Further, when the product S is a liquid crystal display, the pressing force for obtaining sufficient adhesive strength in actual use and handling is 0.5 N / cm ² or more, and the larger the pressing force, the higher the adhesive strength. Tend. However, if the pressing force is too large, the liquid crystal display may be damaged. Therefore, it is preferable to limit the pressing force to 5 N / cm ² or less.

If the effect of eliminating visible bubbles due to the degree of vacuum of the vacuum chamber 20 and the pressing force of the pressing mechanism 16 described above is not sufficient, the autoclave 4 is used. The autoclave 4 is used for the purpose of eliminating (including making invisible) air bubbles generated at the interface between the adhesive R and the work W2 at the time of bonding. Next, the effect of eliminating bubbles by the autoclave 4 will be described with reference to FIG.

FIG. 15 is an explanatory diagram showing the effect of eliminating bubbles by the autoclave 4. FIG. 15 is an experimental verification of the relationship between the bubble size before the autoclave treatment and the bubble size after the autoclave treatment. The horizontal axis represents the bubble size (mm) before the autoclave treatment, and the vertical axis represents the bubble size (mm) after the autoclave. The conditions for the autoclave treatment are the case where the condition indicated by x in the figure is "temperature 40 ° C.-pressure 0.5 MPa" and the condition indicated by the figure ○ is "temperature 60 ° C-pressure 0.5 MPa". This is the result of maintaining this condition for 20 minutes. The bubble size was taken as the average value of the horizontal length and the vertical length of the bubble.

As shown in FIG. 15, when the control condition of the autoclave 4 was "temperature 40 ° C.-pressure 0.5 MPa", some bubbles having a size of 0.8 mm before the autoclave treatment did not disappear. On the other hand, when the control condition of the autoclave 4 is "when the temperature is 60 ° C. and the pressure is 0.5 MPa, all the bubbles disappear until the size before the autoclave treatment is 4.1 mm. This is the adhesive R and the work W2. It can be determined that the air bubbles at the interface of the above are absorbed into the layer of the adhesive R by the autoclave treatment and cannot be visually recognized.

The distribution of bubbles shown in FIG. 15 shows some conditions in the experiment, and the conditions are that the pressure is 0.2 MPa or more and 0.7 MPa or less, the temperature is room temperature or more, and 80 ° C. or less. The effect of reducing air bubbles was observed by performing the autoclave treatment in. However, from the conditions and results of the autoclave treatment shown in FIG. 15, it can be determined that the temperature dependence is high as the condition for eliminating the visible bubbles. Therefore, if the temperature of the autoclave 4 is 50 ° C. or higher and 80 ° C. or lower, the bubble disappearing effect can be further enhanced. As described above, if the temperature of the autoclave 4 is raised, the effect of eliminating bubbles is enhanced, but when the temperature is 80 ° C. or higher, the liquid crystal display may be damaged, so it is preferable to control the temperature to 80 ° C. or lower.

The work bonding device 1 described above is a work bonding device for bonding a pair of works W1 and W2 via an adhesive R. The work bonding device 1 has a coating unit 5 that applies an adhesive R that generates adhesive force by ultraviolet irradiation while moving relative to one work W1 on one side of one of the pair of works W1. An adhesive coating unit 2 having an ultraviolet irradiation unit 6 that irradiates the applied adhesive R with ultraviolet UV, and one work W1 and the other work W2 to which the adhesive R is applied and irradiated with ultraviolet UV. The work bonding unit 3 is provided in a vacuum environment, and the ultraviolet irradiation unit 6 is provided immediately after the start of application of the adhesive R and before the outer peripheral edge of the applied adhesive R is sagging. The adhesive R is configured to irradiate ultraviolet UV rays during the above time period.

The work bonding device 1 starts irradiation with ultraviolet UV immediately after starting the application of the adhesive R, whose adhesive force is generated by irradiation with ultraviolet rays, to the work W1 and before the sagging 26 occurs. As a result, an adhesive force is generated in the adhesive R in the region irradiated with ultraviolet UV, and therefore, due to the wettability of the interface between the adhesive R and the work W1, the sagging generated by flowing along the surface of the work W1. It is possible to suppress 26. Since the work bonding unit 3 has a vacuum chamber 20 and bonds the work W1 and the work W2 in a vacuum environment, it is possible to discharge air bubbles contained in the adhesive R. Further, in the work bonding device 1, a sufficient adhesive force can be obtained by increasing the curing rate of the adhesive R by irradiating with ultraviolet rays and then performing bonding, and a process or device for main curing after bonding as in the prior art. Does not need.

From the above, according to the work bonding device 1, it is possible to suppress the occurrence of sagging 26 on the application start end surface of the adhesive R and to realize a narrow frame of the product S such as a liquid crystal display. Will be. Further, it is possible to reduce the bubbles generated when the work W1 and the work W2 are bonded to each other, and it is possible to obtain good appearance quality including suppressing the sagging 26. Further, after the works W1 and W2 are bonded together, it is possible to obtain sufficient adhesive strength without main curing as in the prior art, and it is possible to shorten the tact time.

In the work bonding device 1, the ultraviolet irradiation unit 6A is configured to collectively irradiate the entire coated surface of the adhesive R with ultraviolet UV rays.

With such a configuration, it is possible to suppress the occurrence of sagging 26, and it is possible to realize a narrow frame of the liquid crystal display as the product S. If the time from the start of application of the adhesive R to the end of application is shorter than the time before the outer peripheral edge of the applied adhesive R is sagging, the entire coated surface after the adhesive is applied. UV UV is collectively irradiated with light energy so that the curing rate of the adhesive R becomes 90% or more. By doing so, it is possible to obtain sufficient adhesive strength with a single ultraviolet irradiation while suppressing the occurrence of sagging 26 without performing the main curing as in the prior art.

The ultraviolet irradiation unit 6B is configured to irradiate the applied adhesive R with ultraviolet UV while following the relative movement of the coating unit 5 or scanning after the application of the adhesive is completed.

With such a configuration, it is possible to suppress the occurrence of sagging 26, and it is possible to realize a narrow frame of the liquid crystal display as the product S. When the time from the start of application of the adhesive R to the end of application by the coating portion 5 is longer than the time until the sagging 26 occurs on the outer peripheral edge portion of the applied adhesive R, for example, when the coating speed is slow or It is possible to cope with the case where the work W1 is long. Of course, it is possible to cope with the case where the time from the start of application of the adhesive R to the end of application is shorter than the time until the outer peripheral edge portion of the applied adhesive R is sagging.

Further, the ultraviolet irradiation unit 6B is further irradiated with ultraviolet UV at a time zone before the sagging 26 occurs on the outer peripheral edge portion of the adhesive R applied immediately after the start of application of the adhesive R, and then at least 1. It is configured to irradiate ultraviolet UV more than once.

If the curing rate does not provide the adhesive strength with one UV irradiation, that is, if the light energy is insufficient, the adhesive R is bonded after the curing rate of the adhesive R is 90% by two or more UV irradiations. I do. By doing so, it is possible to obtain sufficient adhesive strength without main curing after bonding as in the prior art. If a light source having a sufficiently large rated output appears, it is possible to irradiate ultraviolet rays once.

Further, both the ultraviolet irradiation units 6A and 6B are configured so that the elapsed time from immediately after the start of application of the adhesive R to the start of irradiation of ultraviolet UV is within 10 seconds. The sagging width G increases as the elapsed time from the start of adhesive application to the start of ultraviolet irradiation increases. If this elapsed time is set to 10 seconds or less, the curing rate (viscosity) of the surface of the adhesive R irradiated with ultraviolet UV rays increases sharply, and the adhesive R does not flow along the surface of the work W1. It is possible to suppress the sagging width G. By reducing the sagging width G, the sagging 26 cannot be visually recognized even if the widths of the light-shielding films 25A and 25B are reduced in a liquid crystal display or the like, so that a so-called narrow frame design can be realized. Further, it is possible to prevent the adhesive R from sticking out to the side surface of the work W1.

Further, the coating unit 5 increases the moving speed with respect to the steady relative moving speed in response to the change in the coating thickness from immediately after the start of coating the adhesive R until the coating thickness of the adhesive R stabilizes. It is configured to decelerate.

The coating thickness of the adhesive R tends to change until the coating portion 5 reaches a certain distance from the coating start position of the adhesive R. Therefore, in the region where the coating thickness changes, the coating speed is slowed down when the coating thickness is thin with respect to the target coating thickness, and the coating speed is increased when the coating thickness is thick. By doing so, it becomes possible to control the target coating thickness immediately after the start of coating.

Further, between the coating unit 5 and the ultraviolet irradiation unit 6A (or the ultraviolet irradiation unit 6B), a light-shielding plate 11 for blocking ultraviolet UV toward the nozzle tip of the coating unit 5 is disposed, and the tip of the nozzle 10 is provided. When the discharge port of the portion is irradiated with ultraviolet UV rays, the adhesive R may become sticky and clog the nozzle 10. Therefore, a light-shielding plate 11 is arranged between the coating portion 5 and the ultraviolet irradiation portion 6. .. This makes it possible to prevent the nozzle 10 from being clogged.

Further, a stage 8 on which the work W1 is placed is arranged below the coating portion 5, and the stage 8 is subjected to light reflection prevention treatment. With such a configuration, the ultraviolet UV emitted from the ultraviolet irradiation unit 6 is reflected by the stage 8, and it is possible to prevent the ejection port portion of the nozzle 10 from being clogged by irradiating the ejection port portion of the nozzle 10. It will be possible.

Further, the work bonding unit 3 has a pressing mechanism 16 that presses the pair of workpieces W1 and W2 in a stacked state via an adhesive R irradiated with ultraviolet UV rays, and a pair of workpieces W1 and W2 and a pressing mechanism 16. It has a vacuum chamber 20 for accommodating.

In the work bonding unit 3, the work W2 is bonded to the work W1 in an environment where the inside of the vacuum chamber 20 is depressurized from the atmospheric pressure. By bonding the work W1 and the work W2 in an environment where the pressure is lower than the atmospheric pressure, air bubbles caught in the adhesive R when the work W1 and the work W2 are bonded can be discharged. When the product S is required to have visibility such as a liquid crystal display, it is possible to improve the visibility and the appearance quality by discharging bubbles.

Further, when the work W1 and the other work W2 are bonded by the work bonding unit 3, the degree of vacuum of the vacuum chamber 20 is configured to be 100 Pa or less. By setting the vacuum chamber 20 to a vacuum degree of 100 Pa or less when the work W1 and the work W2 are bonded together, air bubbles caught in the adhesive R when the work W1 and the work W2 are bonded are more effectively discharged. Can be done.

Further, when the one work W1 and the other work W2 are bonded by the work bonding unit, the pressing force applied to the pair of works W1 and W2 by the pressing mechanism 16 is 0.5 N / cm2 or more and 5 N / cm2. It is configured as follows.

The adhesive R is a liquid in a normal state, and stickiness is generated by irradiating with ultraviolet UV rays. When the adhesive R is irradiated with ultraviolet UV rays, the curing rate sharply increases. When the works W1 and W2 are bonded together using such an adhesive R, the pressing force is set to 0.5 N / cm ² or more, so that the work W1 and the work W2 are visually caught when they are bonded. It is possible to reduce possible bubbles. Further, by setting the pressing force to 0.5 N / cm ² or more, sufficient adhesive strength in actual use and handling can be obtained. However, if the pressing force is too large, if the product S is a liquid crystal display, the liquid crystal display may be damaged. Therefore, it is preferable to limit the pressing force to 5 N / cm ² or less.

Further, the work bonding device 1 accommodates a pair of bonded works W1 and W2, and controls the internal pressure to 0.2 MPa or more and 0.7 MPa or less and the internal temperature to room temperature or more and 80 ° C. or less. Has 4 more,

If visible air bubbles caught in the adhesive R remain at the stage where the work W1 and the work W2 are bonded to each other to manufacture the product S, the product S is further bonded by autoclaving. It is possible to eliminate the bubbles remaining at the interface between the agent R and the work W1 and W2 and the adhesive R. However, since the temperature dependence is high as a preferable condition for eliminating visible bubbles, if the temperature of the autoclave 4 is set to 50 ° C. or higher and 80 ° C. or lower, the bubble disappearing effect can be further enhanced. If it can be confirmed that the visible bubbles are stably eliminated in the pasting step, the autoclave process can be omitted or the autoclave unit 4 can be omitted.

The work bonding method is a work bonding method in which a pair of works W1 and W2 are bonded via an adhesive R using the work bonding device 1. The work bonding method consists of a coating step of applying an adhesive R whose adhesive force is generated by irradiation with ultraviolet rays to one side of one work W1 while moving relative to one work W1, and a coating process immediately after the start of application of the adhesive R. An ultraviolet irradiation step of irradiating the applied adhesive with ultraviolet UV and a work W1 irradiated with ultraviolet UV at a time zone before the outer peripheral edge of the applied adhesive R is sagging. It includes a step of adhering the other work W2 to the work W2 in the vacuum chamber 20.

According to such a work bonding method, the irradiation of the ultraviolet UV is started immediately after the adhesive R whose adhesive force is generated by the irradiation of the ultraviolet rays is applied to the work W1 and before the sagging 26 is generated. As a result, an adhesive force is generated in the adhesive R in the region irradiated with ultraviolet UV, and therefore, due to the wettability of the interface between the adhesive R and the work W1, the sagging generated by flowing along the surface of the work W1. It is possible to suppress 26, and it is possible to realize a narrow frame of the product S such as a liquid crystal display. Further, it is possible to prevent the adhesive R from sticking out to the side surface of the work W1. In the work bonding step, since the work W1 and the work W2 are bonded in the vacuum chamber 20, visible bubbles contained in the adhesive R can be discharged. Further, in the work bonding step, by increasing the curing rate of the adhesive R by irradiating with ultraviolet rays and then bonding, sufficient adhesive strength can be obtained without the main curing after bonding as in the conventional technique. Therefore, it is possible to shorten the tact time.

Further, in the ultraviolet irradiation step, ultraviolet UV is collectively irradiated to the entire coated surface of the adhesive R. If the time from the start of application of the adhesive R to the end of application by the coating portion 5 is shorter than the time until the sagging 26 occurs on the outer peripheral edge of the applied adhesive R, the coated surface after the adhesive is applied. Ultraviolet UV is collectively irradiated to the entire surface with light energy such that the curing rate of the adhesive R becomes 90% or more. By doing so, it is possible to obtain sufficient adhesive strength with a single ultraviolet irradiation while suppressing the occurrence of sagging 26 without performing the main curing as in the prior art.

Further, in the ultraviolet irradiation step, the applied adhesive R is irradiated with ultraviolet rays while following the relative movement of the coating portion 5. By doing so, it is possible to suppress the occurrence of sagging 26, and it is possible to realize a narrow frame of the liquid crystal display as the product S. In such a method, when the time from the start of application of the adhesive R to the end of application is longer than the time until the sagging 26 occurs on the outer peripheral edge of the applied adhesive R, for example, the application speed is slow. It is possible to deal with the case or the case where the work W1 is long. Of course, it is possible to cope with the case where the time from the start of application of the adhesive R to the end of application is shorter than the time until the outer peripheral edge portion of the applied adhesive R is sagging.

Further, in the work bonding method, the applied adhesive was irradiated with ultraviolet rays immediately after the start of application of the adhesive R and before the outer peripheral edge of the applied adhesive was sagging. Later, it is decided to further irradiate the ultraviolet UV at least once.

If the curing rate does not reach the desired adhesive strength with one UV irradiation, that is, if the light energy is insufficient, the adhesive R is irradiated with the cumulative light energy of the UV UV to be irradiated by two or more UV irradiations. Then, the curing rate is set to 90%, and then the bonding is performed. By doing so, it is possible to obtain sufficient adhesive strength without main curing after bonding as in the prior art. If a light source having a sufficiently large rated output appears, it is possible to irradiate ultraviolet rays once.

Further, in the work bonding method, the pair of bonded works W1 and W2 are conveyed to the autoclave 4, the internal pressure of the autoclave 4 is 0.2 MPa or more and 0.7 MPa or less, and the internal temperature is room temperature or more and 80. It shall be kept below ° C for a predetermined time.

At the stage where the work W1 and the work W2 are bonded together to manufacture the product S, if visible bubbles caught in the adhesive R remain, the product S is further autoclaved. The autoclave treatment makes it possible to eliminate the bubbles remaining at the interface between the adhesive R and the work W1 and W2 and the adhesive R. However, since the temperature dependence is high as a preferable condition for eliminating visible bubbles, if the temperature of the autoclave 4 is set to 50 ° C. or higher and 80 ° C. or lower, the bubble disappearing effect can be further enhanced.

1 ... Work bonding device, 2, 2A, 2B ... Adhesive coating unit, 3 ... Work bonding unit, 4 ... Autoclave, 5 ... Coating section, 6, 6A, 6B ... UV irradiation section, 7A, 7B, 7C, 7D, 7E ... Transfer device, 8, 12, 15 ... Stage, 8a ... Work mounting surface, 9 ... Storage tank, 10 ... Nozzle, 11 ... Shading plate, 16 ... Pressing mechanism, 17 ... Suction plate, 18 ... Drive mechanism , 19, 21 ... Housing, 20 ... Vacuum chamber, 25A, 25B ... Shading film, 26 ... Dripping, 27 ... Convex, G, G1, G2 ... Dripping width, P ... Pump, R ... Adhesive, S ... Product (Liquid crystal display), UV ... Ultraviolet rays, W1 ... Work (liquid crystal module), W2 ... Work (cover glass)

Claims (17)

It is a work bonding device that bonds a pair of workpieces via an adhesive.
An ultraviolet ray is applied to one surface of one of the pair of works, a coating portion to which the adhesive is applied to generate adhesive force by irradiation with ultraviolet rays while moving relative to the one work, and the applied adhesive. An adhesive coating unit having an ultraviolet irradiation part that irradiates the
A work bonding unit for bonding one work and the other work to which the adhesive is applied and irradiated with ultraviolet rays in a vacuum environment.
Have,
The ultraviolet irradiation unit is configured to irradiate the adhesive with ultraviolet rays at a time zone before the outer peripheral edge portion of the adhesive applied immediately after the start of application of the adhesive causes sagging. ,
A work bonding device characterized by this. In the work bonding apparatus according to claim 1,
The ultraviolet irradiation unit is configured to collectively irradiate the entire coated surface of the adhesive with ultraviolet rays.
A work bonding device characterized by this. In the work bonding apparatus according to claim 1,
The ultraviolet irradiation portion is configured to irradiate the applied adhesive with ultraviolet rays while following the relative movement of the coating portion or by scanning after the application of the adhesive is completed.
A work bonding device characterized by this. In the work bonding device according to claim 3,
The ultraviolet-irradiated portion is irradiated with ultraviolet rays at least once after irradiating the ultraviolet rays in a time zone before the outer peripheral edge portion of the adhesive applied immediately after the start of application of the adhesive is sagging. It is configured to irradiate,
A work bonding device characterized by this. In the work bonding apparatus according to any one of claims 1 to 4.
The elapsed time from the start of application of the adhesive to the start of irradiation with ultraviolet rays is configured to be within 10 seconds.
A work bonding device characterized by this. In the work bonding apparatus according to any one of claims 1 to 5.
The coating portion increases or decreases the movement speed with respect to the steady relative movement speed in response to the change in the coating thickness from immediately after the start of application of the adhesive to the stabilization of the coating thickness of the adhesive. Is configured to
A work bonding device characterized by this. In the work bonding apparatus according to any one of claims 1 to 6.
A light-shielding plate that blocks ultraviolet rays toward the nozzle tip of the coating portion is disposed between the coating portion and the ultraviolet irradiation portion.
A work bonding device characterized by this. In the work bonding apparatus according to any one of claims 1 to 7.
A stage on which one of the workpieces is placed is arranged below the coating portion.
The stage is treated to prevent light reflection.
A work bonding device characterized by this. In the work bonding apparatus according to any one of claims 1 to 8.
The work bonding unit has a pressing mechanism that presses the pair of workpieces in a stacked state via the adhesive irradiated with ultraviolet rays, and a vacuum chamber that houses the pair of workpieces and the pressing mechanism. Yes,
A work bonding device characterized by this. In the work bonding apparatus according to claim 9,
When the one work and the other work are bonded by the work bonding unit, the vacuum degree of the vacuum chamber is configured to be 100 Pa or less.
A work bonding device characterized by this. In the work bonding apparatus according to claim 9 or 10.
When the one work and the other work are bonded by the work bonding unit, the pressing force applied to the pair of works by the pressing mechanism is 0.5 N / cm ² or more and 5 N / cm ² or less. Is configured to be,
A work bonding device characterized by this. In the work bonding apparatus according to any one of claims 1 to 11.
It further has an autoclave that accommodates the pair of laminated workpieces and controls the internal pressure to 0.2 MPa or more and 0.7 MPa or less and the internal temperature to room temperature or more and 80 ° C. or less.
A work bonding device characterized by this. A work bonding method for bonding the pair of works via the adhesive using the work bonding device according to any one of claims 1 to 12.
A coating step of applying the adhesive whose adhesive force is generated by irradiation with ultraviolet rays to one side of the one work while moving relative to the one work.
An ultraviolet irradiation step of irradiating the applied adhesive with ultraviolet rays immediately after the start of application of the adhesive and before dripping occurs on the outer peripheral edge of the applied adhesive.
A step of bonding the one work and the other work irradiated with ultraviolet rays in the vacuum chamber, and
including,
A work bonding method characterized by this. In the work bonding method according to claim 13,
In the ultraviolet irradiation step, ultraviolet rays are collectively irradiated to the entire coated surface of the adhesive.
A work bonding method characterized by this. In the work bonding method according to claim 13,
In the ultraviolet irradiation step, the applied adhesive is irradiated with ultraviolet rays while following the relative movement of the coated portion.
A work bonding method characterized by this. In the work bonding method according to claim 15,
Immediately after the start of application of the adhesive, at least once after irradiating the applied adhesive with ultraviolet rays in a time zone before the outer peripheral edge of the applied adhesive is sagging. Irradiate with ultraviolet rays,
A work bonding method characterized by this. In the work bonding method according to any one of claims 13 to 16,
The pair of laminated workpieces are transported to the autoclave and
Further having an autoclave step of maintaining the internal pressure of the autoclave at 0.2 MPa or more and 0.7 MPa or less and the internal temperature at room temperature or more and 80 ° C. or less for a predetermined time.
A work bonding method characterized by this.

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