TWI851399B - Method of bonding sheets - Google Patents

Abstract

A method of bonding sheets is used for a manufacture of a touchpad. The method of bonding sheets includes the following steps: preparing a first sheet and a second sheet, the first sheet having a first surface, an adhesive layer being formed on the first surface, the second sheet having a second surface, a plurality of grooves being formed on the second surface or the adhesive layer, the groove having an opening end in the direction, the grooves extending in parallel in a direction; and bonding the first sheet and the second sheet together through the adhesive layer. Therein, during the bonding process of the first sheet and the second sheet through the adhesive layer, air is discharged between the first sheet and the second sheet through the grooves.

Description

Sheet bonding method

The present invention relates to a sheet bonding method, and in particular to a sheet bonding method used in the manufacture of touch panels.

In the production of touch panels, it is often necessary to bond multiple sheets together. Generally, adhesive is used to bond two sheets. During the bonding process, adhesive will be formed on one of the sheets, and then the two sheets are bonded. However, the bonding area of the sheets is not small, so during the bonding process, air is sometimes trapped between the sheets and the adhesive, forming air bubbles. These air bubbles may not all be expelled by squeezing the sheets, and the remaining bubbles become product defects.

In view of the problems in the prior art, the purpose of the present invention is to provide a sheet bonding method for use in the manufacture of a touch panel. The sheet bonding method uses grooves to exhaust air during the process of bonding the sheets.

A sheet bonding method according to an embodiment of the present invention is used in the manufacture of a touch panel. The sheet bonding method comprises the following steps: (a) preparing a first sheet and a second sheet, the first sheet having a first surface, an adhesive layer formed on the first surface, the second sheet having a second surface, a plurality of grooves formed on the second surface or the adhesive layer, the plurality of grooves extending in parallel in a direction, and the grooves having an open end in the direction; and (b) bonding the first sheet and the second sheet together through the adhesive layer. In the process of bonding the first sheet and the second sheet together through the adhesive layer, air is discharged between the first sheet and the second sheet through the plurality of grooves. Thus, when the first sheet and the second sheet are pressed against each other, the air between the two can flow along the multiple grooves and be discharged through the open end, so the sheet bonding method can effectively suppress the generation of bubbles.

The advantages and spirit of the present invention can be further understood through the following detailed description of the invention and the attached drawings.

Please refer to Figures 1 to 4. According to a first embodiment, a sheet bonding method is used in the manufacture of a touch panel. The sheet bonding method prepares a first sheet 1 and a second sheet 2, as shown in step S100 in Figure 1. The first sheet 1 has a first surface 12, and an adhesive layer 3 is formed on the first surface 12. The second sheet 2 has a second surface 22. A plurality of first grooves 40 are formed on the adhesive layer 3. The plurality of first grooves 40 extend in parallel in a first direction D1 (indicated by arrows in the figure), and the first groove 40 has an open end 402 in the first direction and another open end 404 in the opposite direction to the first direction D1 (as shown in Figure 3). Next, the sheet bonding method bonds the first sheet 1 (the first surface 12) and the second sheet 2 (the second surface 22) together through the adhesive layer 3, as shown in step S102 in FIG1 . The adhesive layer 3 has plasticity; in practice, the adhesive layer 3 can be selected according to actual bonding requirements, such as but not limited to optical adhesive (OCA), hydrogel (OCR), etc. After the first sheet 1 and the second sheet 2 are bonded, the plurality of first grooves 40 disappear, so that the first sheet 1 and the second sheet 2 can be stably bonded together, as shown in FIG4 ; from the perspective of FIG4 , the first sheet 1 and the second sheet 2 are overlapped in the vertical direction Dv (indicated by a double-headed arrow in the figure, which is perpendicular to the first direction D1), and the first surface 12 and the second surface 22 are opposite. During the process of bonding the first sheet 1 and the second sheet 2 together via the adhesive layer 3, air can be discharged between the first sheet 1 (the first surface 12) and the second sheet 2 (the second surface 22) through the plurality of first grooves 40 (via the open ends 402, 404), thereby inhibiting or preventing bubbles from forming between the first surface 12 and the second surface 22.

In addition, as shown in FIG. 5 , in practice, in step S100, the adhesive layer 3 can be formed on the first surface 12 by coating (e.g., painting) or other methods (e.g., OCA double-sided tape), and a release film 6 is attached to the adhesive layer 3 to form the plurality of first grooves 40 (see FIG. 2 ) on the adhesive layer 3. The release film 6 has a plurality of protruding structures 62 that match the plurality of first grooves 40, so when the release film 6 is attached to the adhesive layer 3, the release film 6 will form the plurality of first grooves 40 on the adhesive layer 3 through the plurality of protruding structures 62. In addition, before step S102, the release film 6 needs to be removed from the adhesive layer 3 to expose the plurality of first grooves 40.

In addition, as shown in FIG. 2 , in the first embodiment, the cross section of the first groove 40 is a rectangle, and its width 40a, depth 40b and spacing 40c (i.e., the periodic distance of the plurality of first grooves 40 arranged perpendicular to the first direction D1) can all be determined according to actual bonding tests. Moreover, in practice, the distance from the bottom of the first groove 40 to the first surface 12 (of the first sheet 1) (i.e., the minimum thickness 40d of the adhesive layer 3) can also be determined according to actual tests, for example, the minimum thickness 40d can be designed in accordance with the dimensions of the cross section of the first groove 40 (including the width 40a, depth 40b and spacing 40c), for example, designed to be zero (i.e., directly using the first surface 12 as the bottom of the first groove 40). In addition, in practice, the cross section of the first groove 40 can also be other shapes, for example, the cross section of the first groove 41a shown in FIG6 is arc-shaped, and the cross section of the first groove 41b shown in FIG7 is V-shaped. The above-mentioned various cross-sectional shapes can be realized by designing the size of the protruding structure 62 on the release film 6, which will not be elaborated further. In addition, in practice, the first groove 40 is not limited to a single cross-sectional extension.

In addition, as shown in FIG3 , in the first embodiment, the first groove 40 completely penetrates the surface of the adhesive layer 3 along the first direction D1, but the implementation is not limited to this. For example, as shown in FIG8 , one set of first grooves 41c has only one open end 412c in the first direction D1, and another set of first grooves 41d has only one open end 412d opposite to the first direction D1. The first grooves 41c and the first grooves 41d partially overlap in the horizontal direction Dh (indicated by a double-headed arrow in the figure, which is perpendicular to the vertical direction Dv and the first direction D1), but the implementation is not limited to this.

In addition, in the first embodiment, the adhesive layer 3 covers the entire first surface 12 of the first sheet 1, but this is not limited to this in practice. In addition, the first direction D1 is parallel to the edge of the adhesive layer 3 (also parallel to the edge of the first surface 12), but this is not limited to this in practice. The selection of the first direction D1 can be determined according to the actual bonding method; for example, when the first sheet 1 and the second sheet 2 are rolled by a roller, the first direction D1 can be set to be not perpendicular to the rolling direction, so that during the rolling process, the air between the first sheet 1 and the second sheet 2 can be easily discharged through the first groove 40.

As described above, in the first embodiment, the adhesive layer 3 only has a groove structure extending in a single direction (i.e., the plurality of first grooves 40), but the embodiment is not limited thereto. For example, as shown in FIG9 , the groove structure on the adhesive layer 3 includes a plurality of first grooves 40' and a plurality of second grooves 42, the plurality of first grooves 40' extending in parallel in a first direction D1' (indicated by arrows in the figure), the plurality of second grooves 42 extending in parallel in a second direction D2 (indicated by arrows in the figure), the first direction D1' and the second direction D2 are not parallel, or have an angle A1, and the angle A1 is not 0 or 180 degrees. The first groove 40' has an open end 402' in both the first direction D1' and the direction opposite to the first direction D1'. The second groove 42 has an open end 422 in both the first direction D1' and the direction opposite to the second direction D2. The structures of the first groove 40' and the second groove 42 are logically the same as the first groove 40 in the first embodiment, so the above descriptions of the first groove 40 and its variations are also applicable here and will not be elaborated on. In addition, in FIG9 , the selection of the angle A1 can be determined based on actual bonding tests, such as but not limited to 30 degrees, 45 degrees, 60 degrees, 75 degrees, 90 degrees, 105 degrees, 120 degrees, 135 degrees, 150 degrees, etc.

In addition, in the first embodiment, the plurality of first grooves 40 are formed on the adhesive layer 3, but the implementation is not limited thereto. For example, as shown in FIG10 , a plurality of first grooves 40" are formed on the second surface 22 of the second sheet 2, and the surface of the adhesive layer 3 (such as optical glue or hydrogel) facing the second surface 22 remains flat in principle. As shown in FIG11 , after the first sheet 1 and the second sheet 2 are bonded together via the adhesive layer 3, the structure of the plurality of first grooves 40 is still maintained, and the adhesive layer 3 is tightly fitted to the plurality of first grooves 40. Similarly, in the process of bonding the first sheet 1 and the second sheet 2 together via the adhesive layer 3, air can be discharged between the first sheet 1 (first surface 12) and the second sheet 2 (second surface 22) through the plurality of first grooves 40", thereby inhibiting or preventing bubbles from forming between the first surface 12 and the second surface 22. In addition, in practice, the plurality of first grooves 40" can be formed integrally with the second sheet 2, or formed by setting other structures on the second surface 22 (for example, printing other materials (such as ink) on the second surface 22), but the practice is not limited to this. In addition, the above descriptions of the first grooves 40, 40', the second grooves 42 and their variations are also applicable here (for example, the plurality of second grooves are also formed on the second surface 22 of the second sheet 2), and will not be elaborated on.

Please refer to FIG. 12. According to a second embodiment, a touch panel 5 includes a plate-shaped touch sensing component 52, a plate-shaped light guide structure 54, a cover plate 56 and other required electronic components (not shown in the figure, such as a controller, a light source, etc.). The plate-shaped touch sensing component 52 (such as but not limited to an optical or capacitive plate sensor), the plate-shaped light guide structure 54 (such as but not limited to a light guide plate, and may further include a reflective sheet) and the cover plate 56 (such as but not limited to a light-transmissive glass plate) are stacked together in sequence in the vertical direction Dv. The plate-shaped touch sensing component 52 and the plate-shaped light guide structure 54, and the plate-shaped light guide structure 54 and the cover plate 56 are bonded with adhesive layers 58 and 60, respectively, and the bonding method can adopt the sheet bonding method described above. For example, as shown in FIG13 , in the bonding of the plate-like touch sensing component 52 and the plate-like light guide structure 54, the plate-like light guide structure 54 is regarded as the first sheet material, and the plate-like touch sensing component 52 is regarded as the second sheet material, and the adhesive layer 58 is formed on the surface of the plate-like light guide structure 54 facing the plate-like touch sensing component 52, and the adhesive layer 58 is formed on the surface facing the plate-like touch sensing component 52. A groove structure is formed; in the bonding of the cover plate 56 and the plate-like light guide structure 54, the plate-like light guide structure 54 is regarded as the first sheet material, and the cover plate 56 is regarded as the second sheet material, and the adhesive layer 60 is formed on the surface of the plate-like light guide structure 54 facing the cover plate 56, and the adhesive layer 60 is formed on the surface facing the cover plate 56. In addition, in Figure 13, the adhesive layer 58 can also be modified to be formed on the surface of the plate-like touch sensing component 52 facing the plate-like light-guiding structure 54 (at this time, it is logically equivalent to regarding the plate-like touch sensing component 52 as the first sheet and the plate-like light-guiding structure 54 as the second sheet), and the groove structure is still formed on the adhesive layer 58 (the surface facing the plate-like light-guiding structure 54); similarly, the adhesive layer 60 can also be modified to be formed on the surface of the cover plate 56 facing the plate-like light-guiding structure 54 (at this time, it is logically equivalent to regarding the cover plate 56 as the first sheet and the plate-like light-guiding structure 54 as the second sheet), and the groove structure is still formed on the adhesive layer 58 (the surface facing the plate-like light-guiding structure 54). In addition, the above descriptions of the adhesive layer 3, the first grooves 40, 40', the second groove 42 and their variations (including the location, extension (including the cross section, direction, length, etc.)) are also applicable here and will not be elaborated on separately.

In addition, in practice, the stacking order of the plate-shaped touch sensing component 52, the plate-shaped light guide structure 54 and the cover plate 56 is not limited to that shown in FIG. 12; for example, the plate-shaped touch sensing component 52 is stacked on the plate-shaped light guide structure 54, and the cover plate 56 is stacked on the plate-shaped touch sensing component 52. The sheet bonding method described above can still be used between these three layers of plate-shaped structural components, and no further description is given. In other words, in summary of the above two stacking orders, logically, when the sheet bonding method is applied, two of the group consisting of the plate-shaped touch sensing component 52, the plate-shaped light guide structure 54 and the cover plate 56 can be regarded as the first sheet and the second sheet.

In addition, as shown in FIG. 14 , in practice, the plate-shaped light guide structure 54 may include a light guide plate 542 and a reflective sheet 544. The light guide plate 542 and the reflective sheet 544 are bonded together via an adhesive layer 546. A printing ink layer 548 (for example, to enhance or weaken the reflection effect) is provided on the reflective sheet 544 (the surface facing the light guide plate 542), forming a plurality of first grooves 550. Similarly, the bonding of the light guide plate 542 and the reflective sheet 544 may also adopt the sheet bonding method described above. Among them, the light guide plate 542 is regarded as the first sheet, the reflective sheet 544 is regarded as the second sheet, and the adhesive layer 546 is formed on the surface facing the reflective sheet 544. The above descriptions of the first grooves 40, 40', the second grooves 42 and their variations are applicable here and are also applicable, and will not be elaborated on separately.

The above is only the preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

1: First sheet

12: First surface

2: Second sheet

22: Second surface

3: Adhesive layer

40,40',40",41a,41b,41c,41d: first groove

40a: Width

40b: Depth

40c: Spacing

40d: minimum thickness

402,404,412c,412d: Open end

42: Second groove

422: Open end

5: Touch panel

52: Plate-shaped touch sensor component

54: Plate-shaped light-guiding structure

542: Light guide plate

544:Reflective sheet

546: Adhesive layer

548: Printing ink layer

550: First groove

56: Cover plate

58,60: Adhesive layer

6: Release film

62: Protruding structure

A1: Angle

D1,D1': first direction

D2: Second direction

Dh: horizontal direction

Dv: vertical direction

S100, S102: Steps

Figure 1 is a flow chart of a sheet bonding method according to a first embodiment.

FIG. 2 is a side view of the first sheet and the second sheet prepared according to the sheet bonding method.

Figure 3 is a top view of the adhesive layer on the first sheet in Figure 2.

Figure 4 is a side view of the first sheet and the second sheet bonded according to the sheet bonding method.

Figure 5 is a side view of forming the first groove on the adhesive layer using a release film.

Figure 6 is a schematic diagram of another example of the cross section of the first groove.

Figure 7 is a schematic diagram of another example of the cross section of the first groove.

Figure 8 is a schematic diagram of another example of the first groove arrangement.

Figure 9 is a schematic diagram of another suitable example of the groove structure on the adhesive layer.

Figure 10 is a schematic diagram of another example of the setting of the first groove.

Figure 11 is a schematic diagram of the first sheet and the second sheet in Figure 10 after bonding.

FIG12 is a side view of a touch panel according to a second embodiment.

Figure 13 is a schematic diagram of the bonding of the various plate-like structures in the touch panel in Figure 12.

FIG14 is a schematic diagram showing the bonding of the light guide plate and the reflective sheet of the plate-shaped light guide structure in FIG12 .

1: First sheet

12: First surface

2: Second sheet

22: Second surface

3: Adhesive layer

40: First groove

40a: Width

40b: Depth

40c: Spacing

40d: minimum thickness

D1: First direction

Dv: vertical direction

Claims (10)

A sheet bonding method is used in the manufacture of a touch panel, the sheet bonding method comprising the following steps: (a) preparing a first sheet and a second sheet, the first sheet having a first surface, an adhesive layer formed on the first surface, the second sheet having a second surface, a plurality of first grooves formed on the second surface or the adhesive layer, the plurality of first grooves extending in parallel in a first direction, and the first grooves having an open end in the first direction; and (b) bonding the first sheet and the second sheet together through the adhesive layer; wherein, during the process of bonding the first sheet and the second sheet together through the adhesive layer, air is discharged between the first sheet and the second sheet through the plurality of first grooves. The sheet bonding method as described in claim 1, wherein the plurality of first grooves are formed on the adhesive layer. The sheet bonding method as described in claim 2, wherein in step (a), a release film has a plurality of protruding structures that match the plurality of first grooves, the release film is attached to the adhesive layer and forms the plurality of first grooves on the adhesive layer through the plurality of protruding structures, and before step (b), the release film is removed from the adhesive layer. The sheet bonding method as described in claim 2, wherein the bottom of the first groove is the first surface. The sheet bonding method as described in claim 1, wherein the first sheet and the second sheet are two of a group consisting of a plate-shaped touch sensing component, a plate-shaped light-guiding structure and a cover plate. The sheet bonding method as described in claim 1, wherein the first sheet and the second sheet are a light guide plate and a reflective sheet. The sheet bonding method as described in claim 6, wherein the reflective sheet has a printed ink layer to form the plurality of first grooves. The sheet bonding method as described in claim 1, wherein the cross-section of the first groove is rectangular, arc-shaped or V-shaped. The sheet bonding method as described in claim 1, wherein the first groove has another open end opposite to the first direction. The sheet bonding method as described in claim 1, wherein in step (a), a plurality of second grooves are formed on the second surface or the adhesive layer, the plurality of second grooves extend in parallel in a second direction, the second grooves have an open end in the second direction, and the second direction is not parallel to the first direction.

Images