Case, Portable Device, and Method for Laser Welding Resin Parts

Abstract

A technique for preventing the extrusion of fused material from between resin parts when the resin parts are laser welded. A case has a resin first case part transmissive to laser light and including a peripheral portion. A resin second case part absorbs laser light joined with the first case part. A light reflector reflective to laser light is formed in the peripheral portion of the first case part. A laser welding portion is formed inward from the light reflector between the first case part and the second case part and located at a region reachable by laser light transmitted through the first case part without being reflected by the light reflector. The laser welding portion is for welding the second case part to the first case part with laser light.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:

FIG. 1A is a cross-sectional view of a portable device according to a first embodiment of the present invention;

FIG. 1B is a schematic perspective view showing the portable device of FIG. 1A;

FIG. 2 is a schematic diagram showing a laser welding device;

FIG. 3 is a bottom view showing a laser light path in a state in which a cover is removed from a case of the portable device;

FIG. 4 is an enlarged cross-sectional view showing a flange of a first case part in a state joined with an open end surface of a second case part;

FIG. 5 is a perspective view showing welded portions of the first case part and the second case part;

FIG. 6A is an enlarged perspective view showing a flange in a second embodiment of the present invention;

FIG. 6B is a side view showing the flange of FIG. 6B;

FIG. 7 is an enlarged cross-sectional view showing a flange of a first case part in a state joined with an open end surface of a second case part in another embodiment of the present invention;

FIGS. 8A and 8B are enlarged cross-sectional views each showing a flange of a first case part in a state joined with an open end surface of a second case part in a further embodiment of the present invention;

FIGS. 9A and 9B are side views showing cases in still further embodiments of the present invention:

FIGS. 10A and 10B are schematic diagrams showing laser light emissions in other embodiments of the present invention; and

FIGS. 11A to 11D are cross-sectional views each showing joined portions of two resin parts in further embodiments of the present invention.

Claims

1. A case for accommodating an object, the case comprising: a resin first case part transmissive to laser light and including a peripheral portion;a resin second case part that absorbs laser light joined with the first case part;a light reflector reflective to laser light formed in the peripheral portion of the first case part; anda laser welding portion formed inward from the light reflector between the first case part and the second case part and located at a region reachable by laser light transmitted through the first case part without being reflected by the light reflector, wherein the laser welding portion is for welding the second case part to the first case part with laser light.

2. The case according to claim 1, wherein the first case part includes a light transmissive surface transmissive to laser light and located adjacent to and inward from the light reflector.

3. The case according to claim 2, wherein the light reflector includes an inclined surface inclined relative to the light transmissive surface.

4. The case according to claim 3, wherein the light reflector includes a curved surface.

5. The case according to claim 3, wherein the light reflector includes a recess.

6. The case according to claim 3, wherein the light reflector includes a projection.

7. A portable device for performing predetermined wireless communication with a communication subject, the portable device comprising: a case accommodating an electronic component, the case including: a resin first case part transmissive to laser light and including a peripheral portion;a resin second case part that absorbs laser light joined with the first case part;a light reflector reflective to laser light formed in the peripheral portion of the first case part; anda laser welding portion formed inward from the light reflector between the first case part and the second case part and located at a region reachable by laser light transmitted through the first case part without being reflected by the light reflector, wherein the laser welding portion is for welding the second case part to the first case part with laser light.

8. The portable device according to claim 7, wherein the first case part includes a light transmissive surface transmissive to laser light and located adjacent to and inward from the light reflector.

9. The portable device according to claim 8, wherein the light reflector includes at least one of an inclined surface, a curved surface, a recess, and a projection.

10. A method for laser welding resin parts to manufacture a resin product, the method comprising: preparing a first resin part transmissive to laser light and including a peripheral portion;preparing a second resin part that absorbs laser light;forming a light reflector reflective to laser light in the peripheral portion of the first resin part;joining the first resin part and the second resin part; andlaser welding the second resin part with the first resin part at a location inward from the light reflector by emitting laser light toward the first resin part, transmitting laser light through the first resin part while partially reflecting the laser light with the light reflector, and locally heating and fusing the second resin part with the laser light transmitted through the first resin part.

11. The method according to claim 10, wherein said forming a light reflector includes integrally molding the light reflector with the first resin part.

12. The method according to claim 10, wherein said preparing a first resin part includes forming a light transmissive surface transmissive to laser light at a location adjacent to and inward from the light reflector.

13. The method according to claim 12, wherein said forming a light reflector includes forming an inclined surface inclined relative to the light transmissive surface.

14. The method according to claim 12, wherein said forming a light reflector includes forming a curved surface.

15. The method according to claim 12, wherein said forming a light reflector includes forming a recess.

16. The method according to claim 12, wherein said forming a light reflector includes forming a projection.