JP6829219B2 - Laminating method and laminating device - Google Patents

Description

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

Conventionally, when a pair of workpieces are bonded together with an adhesive, there are a method of curing by ultraviolet (UV) irradiation, a method of heat curing, or a method of combining ultraviolet curing and heat curing. When one of the pair of workpieces is a display module such as a liquid crystal display module and the other workpiece is a top plate such as a touch panel or a protective cover, it is used as an adhesive to improve visibility when the two are bonded together. Optical elastic resin (OCR material: Optical Clear Resin) is used.

The following are disclosed as a method and a bonding device for bonding the display module and the top plate with an optically elastic resin. For example, an ultraviolet curable optical elastic resin is applied to one surface of a display module or a top plate, the applied optical elastic resin is irradiated with ultraviolet rays to temporarily cure the resin, and the other is bonded and then left in the air. There is a method of further curing the optically elastic resin (see Patent Document 1).

Further, an optically elastic resin of a cationically polymerizable resin composition, which is a kind of optically elastic resin, is applied to one surface of the display module or the top plate, and after irradiating with ultraviolet rays, both are bonded and heated to 40 ° C to 80 ° C. There is a method of curing (see, for example, Patent Document 2).

JP-A-2015-13483 JP-A-2009-168903

However, in the bonding method described in Patent Document 1, since the optically elastic resin is temporarily cured by irradiation with ultraviolet rays and then bonded and left in the air for main curing, it takes from the temporary curing to the end of the main curing. There is a problem that it takes a long time and productivity is low.

In the bonding method described in Patent Document 2, after irradiating with ultraviolet rays, both are bonded and heated to 40 ° C. to 80 ° C. to cure the optically elastic resin. For example, if the temperature is raised from room temperature to 80 ° C, it takes a long time to reach 80 ° C, and further, it takes time to lower the temperature to a temperature at which the optically elastic resin can be applied to the next work. .. That is, if the temperature raising time and the temperature lowering time are included, the tact time required for bonding becomes long, and it is difficult to increase the productivity.

Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to provide a bonding method and a bonding device that shortens the tact time required for bonding and dramatically increases productivity. Is.

[1] The bonding method of the present invention is a bonding method in which a pair of workpieces are bonded with an optically elastic resin, and the optically elastic resin that can be cured by irradiating one of the pair of workpieces with ultraviolet rays and heating. The step of applying ultraviolet rays, the step of irradiating the coated optical elastic resin with ultraviolet rays, and the step of irradiating the one of the workpieces with the heater unit, the optical elastic resins maintain the fluidity suitable for bonding the pair of workpieces. After the bonding step of bonding to the other work of the pair of works preheated to the preheating temperature to form a bonded body and the bonding step, the heater unit is used to main-heat to the main heating temperature. A step of heating and curing the optically elastic resin, a step of transferring the bonded body from the heater unit and lowering the temperature to room temperature after continuing the main heating temperature for a predetermined time, and a step of cooling the heater unit to the preheating temperature. When,
It is characterized by including.

According to the bonding method of the present invention, after the applied optically elastic resin is irradiated with ultraviolet rays, the optically elastic resin is bonded at a temperature suitable for bonding a pair of workpieces at a temperature suitable for bonding, and the present heating is performed. The optically elastic resin is heat-cured. The optically elastic resin starts curing by irradiation with ultraviolet rays, but the curing rate is slow, and it takes a long time to reach a predetermined curing rate (for example, about 20 minutes). Therefore, by main heating after irradiation with ultraviolet rays, the curing of the optically elastic resin can be promoted and the time required to reach a predetermined curing rate can be shortened (for example, about 3 minutes). Further, by preheating the other work to a temperature higher than room temperature, the time required to reach the main heating temperature can be shortened. Further, if the heater unit is switched from the main heating temperature to the preheating temperature after the main heating, it is possible to quickly raise the temperature of the next work to be bonded from the room temperature to the preheating temperature. From the above, it is possible to shorten the takt time of bonding and dramatically increase productivity.

[2] In the bonding method of the present invention, the optically elastic resin is obtained by curing a silicone polymer having a vinyl group and a silicone polymer having an H group by a hydrosilylation reaction under a photoactivated platinum catalyst. The preheating temperature is preferably in a temperature range in which the optically elastic resin has a fluidity suitable for bonding the pair of workpieces.

The above-mentioned optical elastic resin is also called a platinum-added OCR material, and has a property that not only a curing action by ultraviolet irradiation due to platinum catalytic action but also a rapid curing progresses by heating after ultraviolet irradiation. The preheating temperature is a temperature at which the optically elastic resin maintains fluidity suitable for bonding the workpieces and is higher than room temperature, and the optically elastic resin is used to eliminate air bubbles between the layers of the pair of workpieces. It is possible to spread over the entire bonding surface and perform bonding.

[3] In the bonding method of the present invention, it is preferable that the preheating temperature is 35 ° C. or higher and 50 ° C. or lower, and the main heating temperature is 70 ° C. or higher and 85 ° C. or lower.

When the preheating temperature is lower than 35 ° C., the time required to reach the main heating temperature during the main heating becomes long. When the preheating temperature is higher than 50 ° C., the viscosity of the optically elastic resin begins to increase, the fluidity decreases, and it becomes difficult to spread on the bonded surface. Further, when the main heating temperature is lower than 70 ° C., it takes a long time for the optically elastic resin to reach a predetermined curing rate. If the main heating temperature is higher than 85 ° C., the time required for curing can be shortened, but it should be 85 ° C. or lower from the viewpoint of balance with the tact time of the entire process including the temperature raising time and the temperature lowering time and energy saving. preferable.

[4] In the bonding method of the present invention, when the one work is used as a liquid crystal display module and the other work is used as a touch panel, the optical elastic resin is applied to the image display surface side of the liquid crystal display module. It is preferable that the display screen side is attached to the touch panel and the main heating temperature is 70 ° C. or higher and 80 ° C. or lower.

When the liquid crystal display module and the touch panel are bonded together, the curing time can be shortened by raising the main heating temperature to 80 ° C., but the liquid crystal or polarizing plate constituting the liquid crystal display module may be altered or deformed. Can be considered. Therefore, if the heating temperature is suppressed below 80 ° C., the optically elastic resin can be cured without adversely affecting the members constituting the liquid crystal display module. When the main heating temperature is lower than 70 ° C., it takes a long time for the optically elastic resin to reach a predetermined curing rate. If an optically elastic resin is filled between the layers of the liquid crystal display module and the touch panel, it is possible to suppress light scattering and diffuse reflection on the image display surface and obtain good visibility.

[5] The bonding device of the present invention is a bonding device for bonding a pair of workpieces with an optically elastic resin, and the optically elastic resin that can be cured by irradiating one of the pair of workpieces with ultraviolet rays and heating. It has a coating part for coating, a UV irradiation part for irradiating the coated optical elastic resin with ultraviolet rays, and a heater unit for preheating the other work of the pair of works, and the optical of the one work. The surface coated with the elastic resin is bonded to the other work, and the bonded portion that is mainly heated to the curing temperature of the optical elastic resin by the heater unit and the pair of bonded works are transferred from the heater unit. It is characterized by having a temperature lowering portion that lowers the temperature from the main heating temperature to room temperature.

According to the bonding device of the present invention, after irradiating the applied optically elastic resin with ultraviolet rays, the optically elastic resin is bonded at a temperature suitable for bonding a pair of workpieces at a temperature suitable for bonding, and the present heating is performed. The optically elastic resin is heat-cured. The optically elastic resin starts curing by irradiation with ultraviolet rays, but the curing rate is slow, and it takes a long time to reach a predetermined curing rate (for example, about 20 minutes). Therefore, by main heating after irradiation with ultraviolet rays, the curing of the optically elastic resin can be promoted and the time required to reach a predetermined curing rate can be shortened (for example, about 3 minutes). Further, by preheating the other work to a temperature higher than room temperature, the time required from the preheating temperature to the main heating temperature can be shortened. Further, if the heater unit is switched from the main heating temperature to the preheating temperature after the main heating, it is possible to quickly raise the temperature of the next work to be bonded from the room temperature to the preheating temperature. From the above, it is possible to shorten the takt time of bonding and dramatically increase productivity. If the bonded work is transferred from the heater unit to the temperature lowering part and the material that has reached room temperature is removed (so-called first-in first-out), the time required for temperature lowering does not affect the takt time.

[6] In the bonding device of the present invention, the heater unit includes a film heater on which the other work is placed, a heat sink arranged below the film heater, and the film heater and the heat sink. It is preferable to have a heat insulating material disposed between them.

Since the film heater has a small heat capacity, the time required for raising and lowering the temperature can be shortened. Further, a heat insulating material is arranged between the film heater and the heat sink, and the heat insulating effect of the heat insulating material suppresses the heat conduction loss between the film heater and the heat sink, and the optical elastic resin 4 is heated from the preheating temperature to the main heating temperature. It is possible to raise the temperature in a short time. Further, if the heat sink is constantly cooled to room temperature or lower, the temperature of the film heater can be lowered from the main heating temperature to the preheating temperature in a short time.

It is sectional drawing which shows the structure of the liquid crystal display 1 which is one example of a pair of workpieces to be bonded in a simplified manner. It is a layout explanatory view which shows the plan structure of the bonding apparatus 10 which concerns on embodiment simply. It is a figure which shows the schematic structure of the coating part 13. It is a figure which shows the schematic structure of the UV irradiation part 14. It is a figure which shows the schematic structure of the bonding part 15. It is a graph which shows an example of the relationship between ultraviolet (UV) irradiation, heating temperature, and curing of an optical elastic resin. It is explanatory drawing which shows the main process of the bonding method which concerns on embodiment.

Hereinafter, the bonding method and the bonding device 10 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 7. A specific work example of the object to be bonded described below will be described as a liquid crystal display 1, one of the pair of works as a liquid crystal display module 2, and the other work as a touch panel 3.

[Configuration of liquid crystal display 1]
FIG. 1 is a cross-sectional view showing a simplified configuration of a liquid crystal display 1 which is an example of a pair of workpieces to be bonded. The liquid crystal display 1 is configured by bonding the liquid crystal display module 2 and the touch panel 3 with an optically elastic resin 4. The optically elastic resin 4 is filled between the liquid crystal display module 2 and the touch panel 3 so that air bubbles do not enter between the layers. The liquid crystal display module 2 is composed of a liquid crystal panel 5 and a backlight 6, and a frame 7 that integrates the liquid crystal panel 5 and the backlight 6. Since the configuration of the liquid crystal display 1 is well known, detailed description thereof will be omitted. The optically elastic resin 4 is a fluid resin having UV curability and heat curability, and the material having a light refractive index after curing is substantially the same as the light refractive index of the touch panel 3 is used. By doing so, it is possible to suppress deterioration of visibility due to scattering and diffuse reflection of light emitted from the image display surface 8.

Although the liquid crystal display 1 is illustrated as one of the workpieces in FIG. 1, it can be adapted to, for example, an organic EL display or another electro-optical display device, and may simply be a glass plate or a resin plate. .. Further, as the other work, a protective cover, a glass plate, a resin plate, or the like may be used in addition to the touch panel 3. The curing characteristics of the optically elastic resin 4 will be described later.

[Structure of bonding device 10]
The bonding device 10 described below illustrates an device for manufacturing a liquid crystal display 1 by bonding a liquid crystal display module 2 and a touch panel 3 with an optically elastic resin 4.

FIG. 2 is an arrangement explanatory view showing a simplified plan configuration of the bonding device 10. The bonding device 10 includes a stocker 11 for a liquid crystal display module and a stocker 12 for a touch panel, and a coating unit 13 for applying an optical elastic resin 4 to the image display surface 8 side of the liquid crystal display module 2. In the bonding device 10, the UV irradiation unit 14 that irradiates the optically elastic resin 4 coated on the liquid crystal display module 2 with ultraviolet rays (UV), the liquid crystal display module 2 irradiated with ultraviolet rays, and the touch panel 3 are bonded and optically elastic. It has a bonding portion 15 that heats the resin 4 to a curing temperature (for example, 75 ° C.). The bonding device 10 further includes a stocker unit 16 as a temperature lowering unit in which the liquid crystal display 1 to which the liquid crystal display module 2 and the touch panel 3 are bonded is left at room temperature to lower the temperature after being heated at a curable temperature for a certain period of time. .. The liquid crystal display 1 whose temperature has been lowered to room temperature is conveyed to the material removing stocker unit 17 to remove the material. The stocker portion 16 may be arranged outside the bonding device 10, or the stocker portion 16 may be removed from the stocker portion 16 without passing through the material removing stocker portion 17.

The liquid crystal display module 2 and the touch panel 3 are each conveyed by the robot arm 18. In FIG. 2, the robot arm 18 shows only the arrangement position. The liquid crystal display module 2 is conveyed from the liquid crystal display module stocker 11 to the coating portion 13 by the robot arm 18 and is coated with the optical elastic resin 4. The liquid crystal display module 2 coated with the optically elastic resin 4 is conveyed to the UV irradiation unit 14 by the robot arm 18 and irradiated with ultraviolet rays. After the irradiation with ultraviolet rays, the liquid crystal display module 2 is conveyed to the bonding unit 15 by the robot arm 18, preheated by the bonding unit 15, and then bonded to the standby touch panel 3 and then heated. In FIG. 2, the movement of the liquid crystal display module 2 is represented by a solid arrow.

The touch panel 3 is conveyed from the touch panel stocker 12 to the bonding portion 15, and is preheated by the film heater 42 (see FIG. 5) at the bonding portion 15. The touch panel 3 waits until the liquid crystal display module 2 is conveyed and ready for bonding. In FIG. 2, the movement of the touch panel 3 is represented by a dotted arrow. In the bonding section 15, the liquid crystal display module 2 and the touch panel 3 are bonded to each other, and the liquid crystal display 1 assembled by main heating is conveyed to the stocker section 16 and a predetermined number is stocked. The heating that promotes the curing of the optical elastic resin 4 with respect to the above-mentioned preheating is referred to as main heating. The liquid crystal display 1 is naturally left in the stocker section 16 until it reaches room temperature, and is conveyed to the material removing stocker section 17 in order from the one cooled to room temperature to remove the material. In FIG. 2, the movement of the liquid crystal display 1 is represented by a chain double-dashed line. The robot arm 18 controls the transfer of the liquid crystal display module 2, the touch panel 3, and the liquid crystal display 1 in the bonding device 10. Next, the configuration of the coating portion 13 will be described with reference to FIG.

FIG. 3 is a diagram showing a schematic configuration of the coating portion 13. FIG. 3A is a front view, and FIG. 3B is an enlarged plan view showing an example of a coating pattern of the optically elastic resin 4. The coating unit 13 moves in the Z-axis direction, the dispenser 21 that discharges the optically elastic resin 4, the X-axis drive unit 22 that moves the dispenser 21 in the X-axis direction, the Y-axis drive unit 23 that moves in the Y-axis direction, and the Y-axis drive unit 23 that moves in the Y-axis direction. It has a Z-axis drive unit 24 and the like. In FIG. 3A, the left-right direction shown is the X-axis, the depth direction of the paper surface is the Y-axis, and the vertical direction with respect to the XY plane is the Z-axis. The liquid crystal display module 2 is placed on the stage 20 with the image display surface 8 facing upward, the dispenser 21 is moved in the X-axis direction, the Y-axis direction, and the Z-axis direction, and the optical elastic resin 4 is applied to the liquid crystal display module 2. To do.

As shown in FIG. 3B, the optically elastic resin 4 is applied to the image display surface 8 of the liquid crystal display module 2 in a convex manner by the dispenser 21. The optically elastic resin 4 is applied to a so-called fishbone pattern in the central portion, and is applied in a plurality of dots on the outer peripheral peripheral edge portion of the image display surface 8. The application of the optically elastic resin 4 is not limited to the pattern shown in FIG. 3 (b), and may be a striped shape using a multi-dispenser. However, at the time of bonding, the optical elastic resin 4 is spread over the entire bonding surface of both while discharging bubbles to the outside between the liquid crystal display module 2 and the touch panel 3, so that the bonding can be performed without bubbles. It is preferable to have a thickness and a flat shape. In the present embodiment, the thickness of the optically elastic resin 4 after bonding is set to 100 μm to 300 μm. At the time of bonding, the optically elastic resin 4 may flow out to the range of the side surface of the liquid crystal panel 5. The liquid crystal display module 2 is fixed to the stage 20, and the optical elastic resin 4 is applied while driving the dispenser 21 in the X-axis direction, the Y-axis direction, and the Z-axis direction. The image display surface 8 is a polarizing plate or a protective film coated on the polarizing plate in the liquid crystal display module 2. Next, the configuration of the UV irradiation unit 14 will be described with reference to FIG.

FIG. 4 is a diagram showing a schematic configuration of the UV irradiation unit 14. The liquid crystal display module 2 coated with the optically elastic resin 4 is conveyed to the UV irradiation unit 14 by the robot arm 18 and attracted to the stage 25. When transporting the liquid crystal display module 2, the UV irradiation unit 26 stands by at a position separated from the liquid crystal display module 2 on the right side in the drawing or the upper side in the drawing. The UV irradiation unit 26 has a housing 27 having an opening on the stage 25 side, and a UV-LED lamp 28 arranged in the housing 27. The UV-LED lamp 28 irradiates the optically elastic resin 4 with light having a predetermined wavelength in the ultraviolet region. Above the housing 27, cooling fans 29 and 29 are arranged to prevent the temperature inside the housing 27 from rising above the preheating temperature.

After the liquid crystal module 2 is transported onto the stage 25, the UV irradiation unit 26 moves to a position where the housing 27 covers the liquid crystal display module 2 and irradiates the optical elastic resin 4 with ultraviolet rays. The cooling fans 29 and 29 maintain the internal temperature of the housing 27 below the preheating temperature while the UV-LED lamp 28 is lit. After a predetermined time has elapsed from the irradiation with ultraviolet rays, the liquid crystal display module 2 is conveyed to the bonding portion 15 by the robot arm 18. Next, the configuration of the bonding portion 15 will be described with reference to FIG.

FIG. 5 is a diagram showing a schematic configuration of the bonding portion 15. 5A is a diagram for explaining the overall configuration, FIG. 5B is a diagram showing a bonding portion 15 before alignment, and FIG. 5C is a diagram showing a bonding portion 15 at the time of bonding. .. As shown in FIG. 5A, the bonding portion 15 includes a heater unit 35 for preheating the touch panel 3 and a heater unit 35 for main heating the optical elastic resin 4 applied to the liquid crystal display module 2 via the touch panel 3. It has a liquid crystal display module material supply unit 36 arranged above the unit 35, and a detection camera 37 that detects the positions of the liquid crystal display module 2 and the touch panel 3. The detection camera 37 shown in FIG. 5A is in a position retracted in the plane direction with respect to the heater unit 35 and the liquid crystal display module material supply unit 36.

The heater unit 35 is arranged in the order of hexapod 38, table 39, heat sink 40, heat insulating material 41, and film heater 42 from the lower side. The hexapod 37 has 6 degrees of freedom in the X-axis direction, the Y-axis direction, the Z-axis direction, the θX direction, the θY direction, and the θZ direction, and drives the table 39 in 6 axes. Cooling air is constantly sent from a jet cooler (not shown) into the heat sink 40 arranged on the upper surface of the table 39. The heat insulating material 41 arranged on the upper surface of the heat sink 40 is provided to suppress heat conduction between the heat sink 40 and the film heater 42. The film heater 42 heats the touch panel 3 to a preheating temperature, attaches the liquid crystal display module 2 to the touch panel 3, and then heats the touch panel 3 to a temperature at which the optical elastic resin 4 is cured. Although the film heater 42 may be a thin plate-shaped ceramic heater, it is preferable that the film heater 42 has a small heat capacity and a short time for raising and lowering the temperature to a set temperature.

The liquid crystal display module material supply unit 36 has a stage 43 that attracts and fixes the liquid crystal display module 2 irradiated with ultraviolet rays, and a swivel mechanism 44 that swivels the stage 43 around the swivel shaft body 45. Since a well-known structure can be adopted for the connecting structure of the swivel shaft body 45 and the stage 43, illustration and description thereof will be omitted. In FIG. 5A, the applied optical elastic resin 4 faces upward, but the rotating mechanism 44 can rotate the optical elastic resin 4 180 degrees around the rotating shaft body 45 so that the optical elastic resin 4 faces the touch panel 3. It has become. The liquid crystal display module material supply unit 36 has an X-axis drive unit, a Y-axis drive unit, and a Z-axis drive unit (not shown), and moves the stage 43 adsorbing the liquid crystal display module 2 in the X-axis, Y-axis, and Z-axis directions. It is possible to make it.

FIG. 5B shows the relationship between the heater unit 35 and the liquid crystal display module material supply unit 36 at the time of alignment. The liquid crystal display module 2 rotates 180 degrees around the swivel shaft body 45 and faces the touch panel 3. The detection camera 37 moves to the space between the liquid crystal display module 2 and the touch panel 3. Alignment markers (not shown) are provided on the liquid crystal display module 2 and the touch panel 3, respectively. The detection camera 37 detects the alignment markers of the liquid crystal display module 2 and the touch panel 3, and the liquid crystal display module 2 and the touch panel 3 respectively. Detects misalignment with. The misalignment is corrected by the hexapod 38. After the position is detected, the detection camera 37 returns to the retracted position (the position indicated by the alternate long and short dash line).

FIG. 5C shows the relationship between the heater unit 35 and the liquid crystal display module material supply unit 36 when the bonding unit 15 is bonded. At the time of bonding, the heater unit 35 is moved upward by the hexapod 38, and the liquid crystal display module material supply unit 36 is moved downward by the Z-axis drive unit (not shown). In this way, the liquid crystal display module 2 and the touch panel 3 are overlapped and pressed. Since the optically elastic resin 4 has fluidity, it spreads over the entire surface of the bonded surface. Then, the optical elastic resin 4 is heat-cured by the film heater 42.

Next, the relationship between ultraviolet (UV) irradiation, heating temperature, and the curing rate of the optically elastic resin will be described. First, the curing characteristics of the optically elastic resin 4 will be described. The optically elastic resin 4 used in the present embodiment is obtained by curing a silicone polymer having a vinyl group and a silicone polymer having an H group by a hydrosilylation reaction under a photoactivated platinum catalyst, and is ultraviolet (UV). ) Has curing characteristics of curing type and heat curing type. At room temperature, such an optically elastic resin 4 has a slow curing rate due to ultraviolet irradiation, and it takes about 20 minutes to reach a predetermined curing level. However, by adding a photoactivated platinum catalyst, an addition reaction is caused and curing by heating is rapidly promoted. In other words, UV irradiation triggers heat curing. Such an optically elastic resin may be referred to as UV-added silicone or platinum-added silicone.

FIG. 6 is a graph showing an example of the relationship between ultraviolet (UV) irradiation, heating temperature, and curing of the optically elastic resin. In FIG. 6, the horizontal axis represents the elapsed time (seconds) starting from ultraviolet (UV) irradiation (indicated by the arrow in the figure), the left vertical scale represents the temperature (° C.), and the right vertical scale represents the curing rate (%). There is. The curing rate is calculated by chemical bond state analysis by the FT-IR method (Fourier Transform Infrared Spectroscopy method). In the figure, the dotted line represents the temperature (° C.) of the optically elastic resin 4, and the solid line represents the curing rate (%) of the optically elastic resin. The optically elastic resin 4 is applied to the liquid crystal display module 2 in an environment of room temperature (20 ° C.) and then irradiated with ultraviolet rays (in the figure, the arrows indicate the start of ultraviolet (UV) irradiation). The temperature of the optically elastic resin 4 is raised to 40 ° C. by attaching the liquid crystal display module 2 to the touch panel 3 which is preheated at the set temperature of the film heater 42 of 40 ° C. After 60 seconds have passed after the irradiation with ultraviolet rays, the set temperature of the film heater 42 is switched to 75 ° C. and heating is started. As shown in FIG. 6, after the irradiation with ultraviolet rays, the curing rate of the optically elastic resin 4 is slow until the main heating is started, and the optically elastic resin 4 has fluidity. Therefore, about 60 seconds after the irradiation with ultraviolet rays, the liquid crystal display module 2 is conveyed to the bonding portion 15, the liquid crystal display module 2 is half-turned, the position is detected, the alignment is performed, and the bonding is performed. When the preheating temperature is lower than 35 ° C., the time required to reach the main heating temperature during the main heating becomes long. When the preheating temperature of the optically elastic resin 4 is higher than 50 ° C., the viscosity starts to increase, and the fluidity decreases at the time of bonding, so that the optically elastic resin 4 does not easily spread on the bonded surface. Therefore, the preheating temperature is preferably 35 ° C. or higher and 50 ° C. or lower.

When the set temperature of the heater unit 35 is switched to 75 ° C., the optically elastic resin 4 reaches the set temperature of 75 ° C. for the main heating in about 72 seconds from the start of heating. The optically elastic resin 4 starts curing by this heating and reaches a curing rate of about 50% in about 10 seconds from the time when it reaches 75 ° C. When the curing rate reaches about 50%, the liquid crystal display module 2 and the touch panel 3 are less likely to be displaced. Therefore, about 10 seconds from the time when the temperature reaches 75 ° C. is called the stabilization time. The curing rate becomes 60% to 70% in about 60 seconds (about 50 seconds from the stabilization time) after reaching 75 ° C. If the curing rate is 60% to 70%, no misalignment will occur in the subsequent work. After about 60 seconds have passed at 75 ° C., the assembled liquid crystal display 1 is transferred from the heater unit 35 (film heater 42) to the stocker section 16 (heating is stopped), and is naturally left in a normal temperature environment to be shown in FIG. As shown in the temperature curve, the temperature is gradually lowered to room temperature. The curing rate of the optically elastic resin 4 gradually increases even while the temperature decreases, and eventually approaches 100%. The temperature curve and the curing rate curve are shown halfway for convenience of illustration.

When the main heating temperature is lower than 70 ° C., it takes a long time for the optical elastic resin 4 to reach the curing rate of 60% to 70%. When the main heating temperature is higher than 85 ° C., the time required for curing can be shortened, but it is preferably 85 ° C. or lower from the viewpoint of balancing the time required for raising and lowering the temperature with the tact time of the entire process and energy saving. .. Therefore, the main heating temperature is preferably 70 ° C. or higher and 85 ° C. or lower.

The relationship between the ultraviolet (UV) irradiation, the heating temperature, and the curing of the optically elastic resin 4 described in FIG. 6 is an example of the case where the liquid crystal display module 2 and the touch panel 3 are bonded together, and depends on the size and configuration of both. different. Further, the preheating temperature, the main heating temperature, the heating time, the working time, and the like are appropriately adjusted depending on the object to be bonded. Next, a method of bonding the liquid crystal display module 2 and the touch panel 3 with the optical elastic resin 4 based on the curing characteristics of the optical elastic resin 4 will be described with reference to FIG. 7.

[Pasting method]
FIG. 7 is an explanatory diagram showing the main steps of the bonding method. FIG. 7 is a diagram showing a bonding operation, and shows the components in a schematic manner. As an example of the object to be bonded, a pair of workpieces will be described as a liquid crystal display module 2 and a touch panel 3. See also FIGS. 1 to 6. First, as shown in FIG. 3, the optical elastic resin 4 is applied to the image display surface 8 side of the liquid crystal display module 2 by the dispenser 21. Subsequently, as shown in FIG. 4, the optical elastic resin 4 is irradiated with ultraviolet rays for about 6 seconds by the UV-LED lamp 28, and then the bonding operation proceeds to the bonding operation shown in FIG.

As shown in FIG. 7A, the touch panel 3 is conveyed from the touch panel stocker 12 onto the film heater 42 of the heater unit 35, preheated at 40 ° C., and stands by. The liquid crystal display module 2 coated with the optical elastic resin 4 by the coating unit 13 is conveyed onto the stage 43 of the liquid crystal display module material supply unit 36. At this time, the applied optical elastic resin 4 faces upward with respect to the touch panel 3. Next, as shown in FIG. 7B, the liquid crystal display module 2 is swiveled 180 degrees around the swivel shaft body 45, and the optical elastic resin 4 side faces the touch panel 3. Subsequently, as shown in FIG. 7C, the positions of the liquid crystal display module 2 and the touch panel 3 are detected by the detection camera 37 (see also FIG. 5B). The detection camera 37 detects the misalignment by photographing the alignment mark (not shown) provided on the liquid crystal display module 2 and the alignment mark (not shown) provided on the touch panel 3 with the CCD camera. At this time, the stage 43 (liquid crystal display module 2) is lowered to a position where the detection camera 37 can detect the alignment mark provided on the liquid crystal display module 2.

Next, as shown in FIG. 7D, the hexapod 38 is driven to shift the position of the touch panel 3 with respect to the liquid crystal display module 2 based on the misalignment information between the liquid crystal display module 2 and the touch panel 3 by the detection camera 37. Correct and align. At this time, the detection camera 37 is retracted. After aligning the touch panel 3 with respect to the liquid crystal display module 2, the stage 43 (liquid crystal display module 2) is lowered, then the touch panel 3 is raised and the optical elastic resin 4 is pressed by the liquid crystal display module 2 and the touch panel 3. Stick them together. After that, it is mainly heated to 75 ° C. by the film heater 42 to cure the optical elastic resin 4 to form the liquid crystal display 1. When one of the workpieces is the liquid crystal display module 2, the main heating temperature is more preferably 70 ° C. or higher and 80 ° C. or lower. It is possible to raise the main heating temperature to 80 ° C. or higher to further shorten the time required for curing, but to prevent deformation or deterioration of the components of the liquid crystal display module 2 such as the liquid crystal and the polarizing plate, the temperature is 80 ° C. or lower. Is more preferable. Further, as described with reference to FIG. 6, the period from the irradiation of ultraviolet rays (UV) to the end of bonding is executed in 60 seconds while maintaining the fluidity that the optical elastic resin 4 can bond, and the film heater 42 heats the resin 4 at 75 ° C. for 60 seconds. By doing so, the optically elastic resin 4 can be cured to a curing rate of 60% to 70%.

After the optically elastic resin 4 is cured, the liquid crystal display 1 is transported from the bonding portion 15 to the stocker portion 16, left in the stocker portion 16 in a room temperature environment to cool down to room temperature, and then transported to the material removing stocker portion 17. Remove the material. In the stocker unit 16, a large number of liquid crystal displays 1 are stocked in a rack or the like, and the liquid crystal displays 1 are transported to the material removal stocker unit 17 in order from the one at room temperature. Therefore, the cooling time does not affect the takt time. After the main heating, the set temperature of the film heater 42 is switched to the preheating temperature. The film heater 42 is cooled by the heat sink 40 and is lowered to the preheating temperature in a short time. In the example of this embodiment, since it is possible to carry out from ultraviolet (UV) irradiation to the end of curing (curing rate 60% to 70%) in about 3 minutes, it is necessary for bonding and curing in a method of only ultraviolet irradiation and not heating. The tact time can be significantly shortened compared to the time of about 20 minutes.

The bonding method described above includes a step of applying an optically elastic resin 4 curable by ultraviolet irradiation and heating to a liquid crystal display module 2 which is one of the pair of workpieces, and an ultraviolet ray to the applied optically elastic resin 4. The liquid crystal in which the optical elastic resin 4 is preheated by the heater unit 35 to a temperature at which the optical elastic resin 4 maintains the fluidity suitable for bonding the liquid crystal display module 2 and the touch panel 3 A bonding step of bonding to the display module 2, a step of heating and curing the optical elastic resin 4 by the heater unit 35 after the bonding step, and a step of continuing the heating temperature for a predetermined time, and then transferring from the heater unit 35. It includes a step of lowering the temperature to room temperature and a step of cooling the heater unit 35 to the preheating temperature.

According to such a bonding method, after the applied optical elastic resin 4 is irradiated with ultraviolet rays, the optically elastic resin 4 is bonded at a temperature that maintains fluidity suitable for bonding the liquid crystal display module 2 and the touch panel. The optical elastic resin 4 is heat-cured by the main heating. The optically elastic resin 4 starts curing by irradiation with ultraviolet rays, but the curing rate is slow, and it takes a long time to reach a predetermined curing rate (curing rate 60% to 70%) (for example, about 20 minutes). Therefore, by main heating after irradiation with ultraviolet rays, the curing of the optically elastic resin 4 can be promoted and the time required to reach a predetermined curing rate of 60% to 70% can be shortened (for example, about 3 minutes). Further, by preheating the touch panel 3 to a temperature higher than room temperature, the time required to reach the main heating temperature can be shortened. Further, if the heater unit 35 is switched from the main heating temperature to the preheating temperature after the main heating, it is possible to quickly raise the temperature of the next touch panel 3 to be bonded from the room temperature to the preheating temperature. From the above, it is possible to shorten the takt time of bonding and dramatically increase productivity. If the liquid crystal display 1 as a laminated body is transferred from the heater unit and the material is removed from the material that has reached room temperature after curing by this heating, the time required for lowering the temperature does not affect the takt time.

Further, in the optically elastic resin 4, a silicone polymer having a vinyl group and a silicone polymer having an H group are cured by a hydrosilylation reaction under a photoactivated platinum catalyst, and preheating is performed by preheating the optically elastic resin 4. The curing rate is slow, and the optically elastic resin 4 is in a temperature range having fluidity suitable for bonding the liquid crystal display module 2 and the touch panel 3.

The optically elastic resin 4 is also called a platinum-added OCR material, and has a property that not only a curing action by ultraviolet irradiation due to platinum catalytic action but also a rapid curing progresses by heating after ultraviolet irradiation. The preheating temperature is a temperature at which the optically elastic resin maintains fluidity suitable for bonding the liquid crystal display module 2 and the touch panel 3, and is higher than room temperature, and the optical elastic resin 4 is referred to as the liquid crystal display module 2. It is possible to spread over the entire bonding surface and perform bonding while eliminating air bubbles between the layers with the touch panel 3.

Further, in the bonding method of the present embodiment, it is preferable that the preheating temperature is 35 ° C. or higher and 50 ° C. or lower, and the main heating temperature is 70 ° C. or higher and 85 ° C. or lower. When the preheating temperature is lower than 35 ° C., the time required to reach the main heating temperature during the main heating becomes long. When the preheating temperature is higher than 50 ° C., the viscosity of the optically elastic resin 4 begins to increase, the fluidity decreases during bonding, and it becomes difficult to spread on the bonding surface. Further, when the main heating temperature is lower than 70 ° C., it takes a long time to reach a predetermined curing rate (60% to 70%) of the optically elastic resin 4. Although the time required for curing can be shortened when the main heating temperature is higher than 85 ° C., it is preferably lower than 85 ° C. from the viewpoint of the balance between the time required for raising and lowering the temperature and the tact time of the entire process and energy saving. ..

When one work is a liquid crystal display module 2 and the other work is a touch panel 3, the optical elastic resin 4 is applied to the image display surface 8 of the liquid crystal display module 2, and the image display surface 8 side is attached to the touch panel 3. It is more preferable that the main heating temperature is 70 ° C. or higher and 80 ° C. or lower.

When the liquid crystal display module 2 and the touch panel 3 are bonded together, the curing time can be shortened by raising the main heating temperature to 80 ° C., but the liquid crystal or the polarizing plate constituting the liquid crystal display module 2 is altered or deformed. It is possible that it will happen. Therefore, if the main heating temperature is suppressed below 80 ° C., the optically elastic resin 4 can be satisfactorily cured without adversely affecting the members constituting the liquid crystal display module 2. Further, if the optical elastic resin 4 is filled between the layers of the liquid crystal display module 2 and the touch panel 3, it is possible to suppress light scattering and diffuse reflection on the image display surface 8 and obtain good visibility.

In the bonding device 10 described above, the liquid crystal display module 2 which is one of the pair of workpieces is coated with the optically elastic resin 4 which can be cured by ultraviolet irradiation and heating, and the coated optically elastic resin. It has a UV irradiation unit 14 that irradiates 4 with ultraviolet rays, and a heater unit 35 that preheats the touch panel 3 which is the other work of the pair of works. The bonding device 10 further includes a bonding section 15 in which the surface of the liquid crystal display module 2 coated with the optical elastic resin 4 is bonded to the touch panel 3 and the heater unit 35 mainly heats the surface to the curing temperature of the optical elastic resin 4. The liquid crystal display 1 as a bonded body to which the liquid crystal display module 2 and the touch panel 3 are bonded is transferred from the heater unit 35 and has a stocker unit 16 which is a temperature lowering unit for lowering the temperature from the main heating temperature to room temperature. ..

According to such a bonding device 10, after the applied optical elastic resin 4 is irradiated with ultraviolet rays, the optical elastic resin 4 maintains a fluidity suitable for bonding the liquid crystal display module 2 and the touch panel. Lamination is performed, and the optical elastic resin 4 is heat-cured by this heating. The optically elastic resin 4 starts curing by irradiation with ultraviolet rays, but the curing rate is slow, and it takes a long time to reach a predetermined curing rate (curing rate 60% to 70%) (for example, about 20 minutes). Therefore, by main heating after irradiation with ultraviolet rays, the curing of the optically elastic resin 4 can be promoted and the time required to reach a predetermined curing rate of 60% to 70% can be shortened (for example, about 3 minutes). Further, by preheating the touch panel 3 to a temperature higher than room temperature, the time required from the preheating temperature to the main heating temperature can be shortened. Further, if the heater unit 35 is switched from the main heating temperature to the preheating temperature after the main heating, it is possible to quickly raise the temperature of the next touch panel 3 to be bonded from the room temperature to the preheating temperature. From the above, it is possible to shorten the takt time of bonding and dramatically increase productivity. If the liquid crystal display 1 after bonding is transferred from the heater unit 35 to the stocker unit 16 and the material at room temperature is removed (so-called first-in first-out), the time required for temperature lowering does not affect the takt time.

Further, the heater unit 35 is arranged between the film heater 42 on which the touch panel 3 which is the other work is placed, the heat sink 40 arranged on the lower side of the film heater, and the film heater 42 and the heat sink 40. It has a heat insulating material 41. Since the film heater 42 has a small heat capacity, the time required for raising and lowering the temperature can be shortened. Further, a heat insulating material 41 is arranged between the film heater 42 and the heat sink 40, and the heat insulating effect of the heat insulating material 41 suppresses the heat conduction loss between the film heater 42 and the heat sink 40, and preheats the optical elastic resin 4. It is possible to raise the temperature from the temperature to the main heating temperature in a short time. Further, if the heat sink 40 is constantly cooled to room temperature or lower, the temperature of the film heater 42 can be lowered from the main heating temperature to the preheating temperature in a short time. Therefore, it is possible to raise the temperature to the main heating temperature and lower the temperature to the preheating temperature in a short time, and the takt time can be shortened.

The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention. For example, in the above-described embodiment, the liquid crystal display unit 2 is coated with the optical elastic resin 4, but the touch panel 2 may be coated with the optical elastic resin 4 and irradiated with ultraviolet rays before preheating. .. Alternatively, the order of preheating and ultraviolet irradiation may be changed, or may be performed at the same time.

Further, in the above-described embodiment, as the optically elastic resin 4, a silicone polymer having a vinyl group and a silicone polymer having an H group are cured by a hydrosilylation reaction under a photoactivated platinum catalyst. .. However, the optically elastic resin is not limited as long as it starts curing slowly by irradiation with ultraviolet rays and is promoted by heating after bonding.

Further, in the above-described embodiment, the temperature is lowered by stocking the liquid crystal display 1 in the stocker portion 16 and leaving it at room temperature after curing, but the cooling time is shortened by sending cooling air to the stocker portion 16. It is possible. Alternatively, if the stocker portion 16 is further heated, the optical elastic resin 4 can be brought close to a curing rate of 100% in a short time.

1 ... Liquid crystal display, 2 ... Liquid crystal display module (one work), 3 ... Touch panel (the other work) 4 ... Optical elastic resin, 8 ... Image display surface, 10 ... Laminating device, 13 ... Coating part, 14 ... UV Irradiation part, 15 ... bonding part, 16 ... stocker part (temperature lowering part), 18 ... robot arm, 35 ... heater unit, 40 ... heat sink, 41 ... heat insulating material, 42 ... film heater

Claims (6)

It is a bonding method in which a pair of workpieces are bonded with an optical elastic resin.
A step of applying the optically elastic resin curable by ultraviolet irradiation and heating to one of the pair of workpieces, and
The step of irradiating the coated optical elastic resin with ultraviolet rays, and
The one work is bonded to the other work of the pair of works preheated by the heater unit to a preheating temperature at which the optically elastic resin maintains the fluidity suitable for bonding the pair of works. The bonding process to make a bonding body and
After the bonding step, a step of main heating to the main heating temperature by the heater unit to heat and cure the optically elastic resin, and a step of heating and curing the optically elastic resin.
After continuing the main heating temperature for a predetermined time, the step of transferring the bonded body from the heater unit and lowering the temperature to room temperature, and
The step of cooling the heater unit to the preheating temperature and
A bonding method characterized by including. In the bonding method according to claim 1,
The optically elastic resin is obtained by curing a silicone polymer having a vinyl group and a silicone polymer having an H group by a hydrosilylation reaction under a photoactivated platinum catalyst.
The preheating temperature is in a temperature range in which the optically elastic resin has a fluidity suitable for bonding the pair of workpieces.
A bonding method characterized by that. In the bonding method of claim 1 or claim 2,
The preheating temperature is 35 ° C. or higher and 50 ° C. or lower, and the main heating temperature is 70 ° C. or higher and 85 ° C. or lower.
A bonding method characterized by that. In the bonding method according to any one of claims 1 to 3,
When the one work is used as a liquid crystal display module and the other work is used as a touch panel, the optical elastic resin is applied to the image display surface side of the liquid crystal display module, and the image display surface side is attached to the touch panel. The main heating temperature is 70 ° C. or higher and 80 ° C. or lower.
A bonding method characterized by that. It is a bonding device that bonds a pair of workpieces with an optical elastic resin.
A coating portion for applying the optically elastic resin curable by ultraviolet irradiation and heating to one of the pair of workpieces, and a coating portion.
A UV irradiation unit that irradiates the coated optical elastic resin with ultraviolet rays,
It has a heater unit that preheats the other work of the pair of works, and the surface of the one work coated with the optical elastic resin is attached to the other work, and the optical elastic resin is attached by the heater unit. With the bonding part that is fully heated to the curing temperature of
A temperature lowering unit that transfers the pair of bonded workpieces from the heater unit and lowers the temperature from the main heating temperature to room temperature.
A laminating device characterized by having. In the bonding device according to claim 5 ,
The heater unit has a heater on which the other work is placed, a heat sink arranged on the lower side of the heater, and a heat insulating material arranged between the heater and the heat sink.
A laminating device characterized by that.