Next method

Abstract

To provide a technique for increasing adhesive strength between a glass component and a resin component.SOLUTION: A bonding method bonds a glass component 210 having a first surface and a second surface facing an opposite side to the first surface, and a resin component 230. Printing by acrylic ink is performed on the first surface 212 of the glass component 210, the first surface 212 of the glass component 210 and the resin component 230 are made to face each other, and the glass component 210 and the resin component 230 are overlapped. An IR laser beam 300 is emitted toward a print 216 from the first surface 212 of the glass component 210, and the glass component 210 and the resin component 230 are welded by melting heat of the print 216.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a bonding technique, and more particularly to a bonding method for bonding a glass component and a resin component. [Background technology]

[0002] The manufacturing process of a display includes various thermal processes, one of which is a process for airtightly bonding a front glass substrate and a rear glass substrate. For example, to bond two pieces of glass together, a thin film that absorbs laser light is sandwiched between them, and the thin film is irradiated with laser light that passes through the glass plate. As a result, the two pieces of glass sandwiching the thin film are fused together by the heat generated by the thin film (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-26127 Summary of the Invention [Problem to be solved by the invention]

[0004] The manufacturing process of displays also includes the process of bonding glass and resin components. Until now, adhesive bonding, using double-sided tape or adhesive, has been widely used to bond glass and resin components. However, adhesive bonding has a relatively weak adhesive strength, so the bonding area must be large to increase the adhesive strength.

[0005] The present disclosure has been made in view of these circumstances, and its purpose is to provide a technique for increasing the adhesive strength between a glass component and a resin component. [Means for solving the problem]

[0006] In order to solve the above problems, a bonding method according to one embodiment of the present disclosure is a bonding method for bonding a glass component having a first surface and a second surface facing away from the first surface to a resin component, wherein the first surface of the glass component is printed with acrylic ink, and the method includes the steps of: placing the first surface of the glass component opposite the resin component and overlapping the glass component and the resin component; and irradiating a laser beam from the second surface of the glass component toward the print and fusing the glass component and the resin component using the heat of melting the print. [Effects of the Invention]

[0007] According to the present disclosure, the adhesive strength between the glass component and the resin component can be increased. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 10 is a cross-sectional view showing the structure of a display according to a comparative example of the embodiment. [Figure 2] 5A to 5C are cross-sectional views showing a manufacturing process of the display according to the embodiment. [Figure 3] 3(a)-(d) are partial cross-sectional views showing the manufacturing process of the display following FIG. [Figure 4] 1 is a cross-sectional view showing a structure of a display according to an embodiment. [Figure 5] 5(a) and 5(b) are diagrams showing the structure of a sample used in the examples. [Figure 6] FIG. 6 is a diagram showing experimental results using the sample of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0009] Before describing the embodiments of the present disclosure in detail, an outline of the embodiments will be described. The embodiments relate to a bonding method for bonding a cover glass (glass component) and a case (resin component) in a process for manufacturing a display to be mounted on a vehicle. As described above, glass components and resin components have traditionally been bonded together using double-sided tape or adhesive, but the adhesive strength of double-sided tape and the like is relatively weak. As a result, the bonding area is increased to increase the adhesive strength. In addition, there are issues with the bonding process taking time because double-sided tape or adhesive application is required, and the number of components increases because double-sided tape or adhesive is required in addition to the glass component and the resin component.

[0010] In order to increase the adhesive strength between the glass member and the resin member, in this embodiment, the glass member and the resin member are laser-welded via ink. However, when the conditions for laser welding two glass members are used, the resin member becomes too hot and melts completely. On the other hand, if the laser irradiation is insufficient to prevent the resin member from melting, sufficient adhesive strength cannot be obtained. For this reason, in this embodiment, an acrylic ink is used as the ink.

[0011] In the following explanation, "parallel" and "orthogonal" do not only mean completely parallel or orthogonal, but also include cases where they deviate from parallel or orthogonal within a margin of error. Also, "substantially" means that they are roughly the same.

[0012] Here, we will first explain the structure of a conventional display 100 that uses double-sided tape. FIG. 1 is a cross-sectional view showing the structure of a comparative display 100. The display 100 includes a glass component 10, a liquid crystal component 20, a backlight 22, a resin component 30, and double-sided tape 40. A user is present above the display 100 in FIG. 1, and the user views an image displayed on the display 100 from above. Also, a device equipped with the display 100 is placed below the display 100 in FIG. 1, and the device outputs a video signal to the display 100. Therefore, when the upper side of the display 100 is called the "user side," the lower side of the display 100 is called the "internal device side."

[0013] The glass component 10 is a cover glass, also called a glass plate. The surface of the glass component 10 facing the interior of the device is a first surface 12, and the surface of the glass component 10 facing the user is a second surface 14. The first surface 12 and the second surface 14 face opposite each other. When viewed from the user side, the glass component 10 has a rectangular shape, and a frame-shaped print 16 is arranged on the outer edge of the first surface 12. The print 16 is, for example, black.

[0014] A liquid crystal component 20 is disposed in the central portion of the first surface 12 of the glass component 10 where no printing 16 is provided. The liquid crystal component 20 includes a color filter, liquid crystal, transparent electrodes, etc. A backlight 22 is disposed on the internal side of the liquid crystal component 20. When an image is displayed on the liquid crystal component 20, the backlight 22 irradiates light from the internal side, thereby brightening the screen.

[0015] The resin component 30 has an opening in the center of its user-facing surface, which penetrates to the interior side to form a through-hole. The glass component 10 can be attached to the opening in the resin component 30 from the user side. The liquid crystal component 20 and backlight 22 are also disposed within the through-hole. Double-sided tape 40 is attached to the interior side of the print 16 on the first surface 12 of the glass component 10. The double-sided tape 40 may have a frame shape, similar to the print 16. The interior side of the double-sided tape 40 is attached to the resin component 30. As a result, the glass component 10 and the resin component 30 are bonded together by the double-sided tape 40.

[0016] The bonding method according to this embodiment will be described below in the order of (1) the overlapping step and (2) the laser irradiation step. (1) Layering process 2 is a cross-sectional view showing a manufacturing process of display 200. Display 200 includes a glass component 210, a liquid crystal component 220, a backlight 222, and a resin component 230. Display 200, glass component 210, liquid crystal component 220, backlight 222, and resin component 230 correspond to display 100, glass component 10, liquid crystal component 20, backlight 22, and resin component 30 in FIG. 1, respectively. Furthermore, when the upper side of display 200 in FIG. 2 is called the "user side," the lower side of display 200 is called the "internal device side."

[0017] The surface of the glass component 210 facing the interior of the device is the first surface 212, and the surface of the glass component 210 facing the user is the second surface 214. The first surface 212 and the second surface 214 face opposite each other. The glass component 210 has the property of transmitting laser light. The laser light is emitted from, for example, a 940 nm semiconductor laser as a light source. When viewed from the user side, the glass component 210 has a rectangular shape, and a frame-shaped print 216 is disposed on the outer edge of the first surface 212. The print 216 is formed of a material that absorbs laser light, such as an acrylic ink. For example, the thickness of the print 216 is less than 30 μm. The thickness of the print 216 may be 5 μm or more. The print 216 is, for example, black.

[0018] The liquid crystal component 220 is disposed in a central portion of the first surface 212 of the glass component 210 where the printing 216 is not formed. A backlight 222 is disposed on the internal device side of the liquid crystal component 220. The resin component 230 has an opening in the central portion of the user-side surface, which penetrates all the way to the internal device side to form a through-hole. The glass component 210 can be attached to the opening of the resin component 230 from the user side. The liquid crystal component 220 and the backlight 222 are disposed in the through-hole. The resin component 230 contains, for example, an acrylic resin, which is the same type of material as acrylic ink. The glass component 210 and the resin component 230 are overlapped with each other, with the first surface 212 of the glass component 210 and the resin component 230 facing each other.

[0019] (2) Laser irradiation process 3(a)-(d) are partial cross-sectional views showing the manufacturing process of display 200. FIGS. 3(a)-(d) are enlarged views of a portion of FIG. 2. A glass coating 218 is disposed on second surface 214 of glass component 210. Glass coating 218 also has the property of transmitting laser light. As shown in FIG. 3(a), an IR (infrared) laser 300 is irradiated from second surface 214 of glass component 210 toward print 216. IR laser 300 passes through glass coating 218 and glass component 210.

[0020] FIG. 3(b) shows a state following FIG. 3(a). The IR laser 300 passes through the glass component 210 and reaches the printing 216. As a result, the printing 216 is irradiated by the IR laser 300. FIG. 3(c) shows a state following FIG. 3(b). The printing 216 generates heat and melts when irradiated by the IR laser 300. Furthermore, the heat of melting generated from the printing 216 melts a portion of the resin component 230 close to the printing 216. FIG. 3(d) shows a state following FIG. 3(c). After the portion of the resin component 230 close to the printing 216 melts, that portion is cooled, solidifying and forming a welded portion 250. The glass component 210 and the resin component 230 are welded by the welded portion 250.

[0021] Fig. 4 is a cross-sectional view showing the structure of display 200. Fig. 4 corresponds to the overall structure of Fig. 3(d). Fig. 4 is shown in the same manner as Fig. 2, but a welding part 250 is disposed between glass component 210 and resin component 230, and welding part 250 welds glass component 210 and resin component 230 together.

[0022] (Example) Experiments were conducted to determine the type of ink to be used for the print 216 and the thickness of the print 216. FIGS. 5(a) and 5(b) are diagrams showing the structure of a sample 400 used in the examples. FIG. 5(a) is a side view of the sample 400, and FIG. 5(b) is a top view of the sample 400. A print 416 is disposed on a first surface 412 of a glass component 410. The combination of the glass component 410 and the print 416 is, for example, 100 mm long, 25 mm wide, and 3.0 mm thick. The resin component 430 is, for example, 100 mm long, 25 mm wide, and 1.8 mm thick. The combination of the glass component 410 and the print 416 and the resin component 430 overlap by 12.5 mm in the longitudinal direction. This overlapping portion is referred to as an overlapping portion 460. In this state, the glass component 410 and the resin component 430 are fused together using an IR laser 300 (not shown), forming a welded portion 450. The portion of resin part 430 opposite overlapping part 460 is first gripping part 470a, and the portion of the combination of glass part 410 and print 416 opposite overlapping part 460 is second gripping part 470b.

[0023] The glass part 410 was manufactured from soda lime blue plate glass, and the resin part 430 was manufactured from a PCABS test piece. The PCABS test piece was made of acrylic resin. In the experiment, a print 416 was formed using a urethane-based ink and an acrylic-based ink. The urethane-based ink was 1st: HF GV3 RX01 710 Black / 2nd: HF SG460 NSY1312T-2 Black (Seiko Advance Co., Ltd.), and the acrylic-based ink was IRX-HF Black (Teikoku Ink Co., Ltd.). The urethane-based ink was made of a different material than the resin part 430, and the acrylic-based ink was made of the same material as the resin part 430. In the experiment, the thickness of the print 416 was varied between 5 μm, 10 μm, and 30 μm. The output of the IR laser 300 used for welding was set to 15 W, the spot diameter was set to φ3 (mm), and the laser irradiation speed was changed to 10 (mm / sec), 15 (mm / sec), and 20 (mm / sec).

[0024] FIG. 6 shows the experimental results for sample 400. This shows the strength (MPa) and appearance results of an experiment using sample 400. FIG. 6 also shows the results of a comparison with when a glass component 410 and a resin component 430 were bonded using double-sided tape (3M). The strength was measured by pulling the first gripping portion 470a and the second gripping portion 470b using a universal testing machine, Autograph AG-X 20kNX (Shimadzu Corporation). The appearance was observed visually. When urethane-based ink was used, the strength was such that the sample broke during transportation, and the appearance showed ink peeling.

[0025] When acrylic ink was used, the strength was such that the print broke during transportation when the thickness was 5 μm and the laser irradiation speed was 20 mm / sec, and when the thickness was 30 μm and the laser irradiation speed was 20 mm / sec. However, under other conditions, the strength was greater than when adhered with double-sided tape. Furthermore, when the thickness was 30 μm and the laser irradiation speed was 10 mm / sec, the ink peeled off. However, under other conditions, there was no abnormality in the appearance. Increasing the thickness of the acrylic ink from 5 μm increases the amount of acrylic ink, and therefore the strength (MPa) increases. On the other hand, when the thickness of the acrylic ink reaches 30 μm, the IR laser 300 no longer melts the print 416 sufficiently, and the strength (MPa) decreases.

[0026] For these reasons, acrylic ink is more suitable than urethane ink for printing 416. In particular, a thickness of less than 30 μm and greater than 5 μm is suitable for acrylic ink. However, printing thicknesses of less than 5 μm are not recommended because it is difficult to achieve a uniform thickness after application.

[0027] According to this embodiment, by bonding a glass component printed with acrylic ink to a resin component by irradiating the glass component with laser light, the adhesive strength between the glass component and the resin component can be increased. Furthermore, because the adhesive strength is increased, the adhesive area can be reduced. Furthermore, because the adhesive area is reduced, a narrower frame is possible, improving design freedom. Furthermore, because the resin component and the print are made of the same material, the adhesive strength between the glass component and the resin component can be increased. Furthermore, because the print thickness is less than 30 μm, the print can be sufficiently melted. Furthermore, because the print thickness is 5 μm or more, a situation in which the acrylic ink is insufficient can be avoided.

[0028] An overview of one aspect of the present disclosure is as follows: A bonding method according to one aspect of the present disclosure is a bonding method for bonding a glass component having a first surface and a second surface facing opposite the first surface to a resin component, wherein the first surface of the glass component is printed with acrylic ink, and the method includes the steps of: bringing the first surface of the glass component and the resin component opposite each other and overlapping the glass component and the resin component; and irradiating a laser beam from the second surface of the glass component toward the print to fuse the glass component and the resin component together using the heat of melting the print.

[0029] According to this aspect, the glass component printed with acrylic ink and the resin component are bonded together by irradiation with laser light, so that the adhesive strength between the glass component and the resin component can be increased.

[0030] The resin part may contain acrylic resin. In this case, the resin part and the print are made of the same material, which increases the adhesive strength between the glass part and the resin part.

[0031] The thickness of the printing applied to the first surface of the glass component in the overlapping step may be less than 30 μm. In this case, the printing thickness is set to less than 30 μm, so that the printing can be sufficiently melted.

[0032] The thickness of the print made on the first surface of the glass component in the overlapping step may be 5 μm or more. In this case, since the print thickness is 5 μm or more, it is possible to avoid a situation where the acrylic ink is insufficient.

[0033] The present disclosure has been described above based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component or each treatment process, and that such modifications are also within the scope of the present disclosure.

[0034] The bonding method according to this embodiment bonds a cover glass (glass component) and a case (resin component). However, the present invention is not limited to this, and the bonding method according to this embodiment may be used to bond a glass component other than the cover glass and a resin component other than the case. This modification expands the scope of application of this embodiment. [Explanation of symbols]

[0035] 200 Display, 210 Glass parts, 212 First surface, 214 Second surface, 216 Printing, 218 Glass coating, 220 Liquid crystal parts, 222 Backlight, 230 Resin parts, 250 Welded parts, 300 IR laser.

Claims

1. A bonding method for bonding a glass component having a first surface and a second surface facing away from the first surface to a resin component, the method comprising: a step of overlapping the glass component and the resin component, the glass component having the first surface printed with acrylic ink and the resin component facing the first surface of the glass component; irradiating the second surface of the glass component with a laser beam toward the print to fuse the glass component and the resin component together by heat from melting the print; A bonding method comprising:

2. The bonding method according to claim 1 , wherein the resin part contains an acrylic resin.

3. 3. The bonding method according to claim 1, wherein the thickness of the printing on the first surface of the glass component in the overlapping step is less than 30 μm.

4. 4. The bonding method according to claim 1, wherein the thickness of the printing on the first surface of the glass component in the overlapping step is 5 μm or more.

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