Sealing method

Abstract

A sealing method includes dispensing an adhesive on an edge surface of a first part, performing a first activation for hardening the adhesive to a predetermined hardness, performing a second activation for triggering appearance of adhesion strength of the adhesive, assembling the first part and a second part, and pressing the first part and the second part against each other.

Claims

1. A sealing method for sealing a boundary between a first part and a second part, wherein the sealing method comprises: dispensing an adhesive on an edge surface of the first part, wherein the first part is a housing, and wherein the adhesive comprises a denatured silicone adhesive or a denatured acrylate adhesive; performing a first activation for hardening the adhesive to a predetermined hardness; performing a second activation for triggering appearance of adhesion strength of the adhesive; assembling the first part and the second part, wherein the second part is a touch panel; and pressing the first part and the second part against each other.

2. The sealing method of claim 1, further comprising performing the second activation after assembling the first part and the second part.

3. The sealing method of claim 1, wherein the adhesive comprises urethane-acrylic adhesive.

4. The sealing method of claim 1, further comprising further dispensing the adhesive using an air dispensing method.

5. The sealing method of claim 1, wherein the first activation comprises cooling the adhesive, shocking the adhesive, or adding moisture to the adhesive.

6. The sealing method of claim 1, wherein a first time for performing the first activation is greater than one minute, wherein a second time for assembling the first part and the second part is less than one minute, and wherein a third time for performing the second activation to reach a predetermined adhesion strength of the adhesive is greater than one hour.

7. The sealing method of claim 1, wherein a time from a completion of the first activation to a start of the second activation does not comprise a limit.

8. The sealing method of claim 1, wherein the adhesive comprises an epoxy adhesive.

9. The sealing method of claim 1, wherein the adhesive comprises an ultraviolet (UV) curing adhesive.

10. The sealing method of claim 1, wherein the adhesive comprises an ultraviolet (UV) and moisture curing adhesive.

11. The sealing method of claim 1, further comprising further dispensing the adhesive using a jet dispenser method.

12. The sealing method of claim 1, further comprising further dispensing the adhesive using a screw pump method.

13. The sealing method of claim 1, further comprising further dispensing the adhesive using a slit coating method.

14. The sealing method of claim 1, further comprising further performing the second activation by irradiating ultraviolet (UV) light to the adhesive.

15. The sealing method of claim 1, further comprising further performing the second activation by adding moisture to the adhesive.

16. The sealing method of claim 1, further comprising further performing the second activation by heating the adhesive.

17. A terminal prepared by a processing comprising the steps of: dispensing an adhesive on an edge surface of a first part, wherein the first part is a housing, and wherein the adhesive comprises a denatured silicone adhesive or a denatured acrylate adhesive; performing a first activation for hardening the adhesive to a predetermined hardness; performing a second activation for triggering appearance of adhesion strength of the adhesive; assembling the first part and a second part, wherein the second part is a touch panel; and pressing the first part and the second part against each other.

18. The terminal of claim 17, wherein the first activation comprises cooling the adhesive, shocking the adhesive, or adding moisture to the adhesive.

19. The terminal of claim 17, wherein the adhesive further comprises an epoxy adhesive, an ultraviolet (UV) curing adhesive, an ultraviolet (UV) and moisture curing adhesive, or urethane-acrylic adhesive.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows a side view (a cross-sectional view) of a smart phone in a prior art;

(2) FIG. 2 shows a side view (a cross-sectional view) of a housing and a touch panel of a smart phone in another prior art;

(3) FIG. 3 shows a side view (a cross-sectional view) of a smart phone according to an embodiment of the present invention;

(4) FIG. 4 shows a side view (a cross-sectional view) of a housing and a touch panel of a smart phone according to an embodiment of the present invention;

(5) FIG. 5 shows a flow chart of a sealing method for sealing a boundary between a housing and a touch panel according to an embodiment of the present invention;

(6) FIG. 6 shows a graph indicating transition with lapse of time in the process of hardness and adhesion strength of the adhesive.

DESCRIPTION OF EMBODIMENTS

(7) FIG. 3 shows a side view (a cross-sectional view) of a smart phone after assembly is completed according to an embodiment of the present invention. A housing 1 and a touch panel 2 are adhered together by an adhesive 4. The housing 1 and a back cover 3 is also adhered together by the adhesive 4. Spacers and a channel are not provided on an edge surface for adhesion of the housing 1. When pressure is applied to bond the housing 1, the touch panel 2, and the back cover 3, an adequate thickness h of an adhesive layer is kept without spacers, and the adhesive 4 is not squeezed outside the housing 1 without a channel, because the adhesive 4 is hardened to semi solid state before pressure is applied. W is the width of the edge surface for adhesion. The entire width W contributes to adhesion, that is, substantial adhesion width is wider than that in the prior art because of omitting the spacers or channel on the edge surface of the housing 1. The widened substantial adhesion width improves adhesion strength and reliability of waterproof. In other words, the entire width W of the edge surface for adhesion can be minimized while adhesion strength and reliability of waterproof are maintained, and narrow edge width with adhesion strength and reliability of waterproof is realized.

(8) FIG. 4 shows a side view (a cross-sectional view) of the housing 1 and the touch panel 2 of a smart phone before and after assembly according to the embodiment of the present invention. Thickness h is the thickness of dispensed and hardened adhesive 4. Width W2 of dispensed and hardened adhesive 4 is narrower than width W of the edge surface for adhesion. After assembly and compression, the adhesive 4 is not flattened, and keeps an adequate thickness, because the adhesive 4 is hardened to semi solid state before compression.

(9) Furthermore, thickness T2 of the housing 1 without a channel according to the present invention is thinner than thickness T1 of the housing 1 with the channel 6 in the prior art.

(10) Material of the housing 1 is plastic, metal, and so on. Examples of the plastic include PBT, PPS, PC, PAEK, and so on. Examples of the metal include aluminum, stainless steel, magnesium, and so on.

(11) Examples of the adhesive 4 include urethane-acrylic adhesive, epoxy adhesive, denatured silicone adhesive, denatured acrylate adhesive, UV curing adhesive, UV and moisture curing adhesive, and so on.

(12) Examples of method for dispensing the adhesive 4 include air dispense method, jet dispenser method, screw pump method, slit coating method, and so on.

(13) FIG. 5 shows a flow chart indicating a process for assembling a housing 1 and a touch panel 2 of a smart phone according to an embodiment of the present invention. FIG. 6 shows a graph indicating transition with lapse of time (on horizontal axis) in the process of hardness (on left vertical axis) and adhesion strength (on right vertical axis) of the adhesive 4.

(14) In step S1, if the adhesive 4 is not soft enough for the following dispensing, the adhesive 4 is heated. Otherwise, this step is not needed.

(15) In step S2, the adhesive 4 is dispensed on an edge surface for adhesion of the housing 1.

(16) In step S3 of a first activation, the adhesive 4 is cooled for a few minutes to harden the adhesive 4. The adhesive 4 is transformed from liquid state to semi solid state. In the first activation, appearance of adhesion strength of the adhesive 4 is not triggered yet.

(17) In step S4 of a second activation, ultraviolet (UV) light is irradiated to the adhesive 4 to trigger appearance of adhesion strength of the adhesive 4, just before the following step 5 of assembly.

(18) In step S5, the housing 1 and the touch panel 2 are assembled. Print may be applied on inside surface of the touch panel 2, that is, the touch panel 2 may not be transparent. Therefore, this step of assembly is performed after irradiating UV light to the adhesive 4 for trigger. Time required for assembly is about 30 to 60 seconds, for example. The adhesion strength of the adhesive 4 is low within this lapse of time. Thus, the adhesion strength is not spoiled.

(19) One of the suitable method of second activation is irradiating UV light. In case of using a type of adhesive to which UV light is irradiated to trigger appearance of adhesion strength, the second activation should be performed before assembly. There exists such kind of adhesive. If other type of adhesive to which moisture is given or heat is applied for trigger is used, the second activation can be performed after assembly.

(20) In step S6, the housing 1 and the touch panel 2 are pressed against each other to bond them together for about several hours to one day, for example. An adhesive layer keeps adequate thickness, since the adhesive 4 was hardened to semi solid state in the preceding step S3 of the first activation. The adhesion strength of the adhesive 4 gradually increases for this lapse of time. When the adhesion strength reaches sufficient adhesion strength which overcomes internal pressure, the process is completed.

(21) Time from completion of step S3 of the first activation to start of step 4 of the second activation is free. Thus, step S5 of assembly can be started at any desired point in time.

(22) Alternatively, the first activation includes shocking the adhesive 4 or giving moisture to the adhesive 4. The second activation includes giving moisture to the adhesive 4 or heating the adhesive 4.