IN-MOLDED CAPACITIVE SENSORS

• US 20100013499A1
• Filed: 07/18/2008
• Published: 01/21/2010
• Est. Priority Date: 07/18/2008
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Tong, Tony, Kellogg, David Dwight
• Granted Patent: US 8,238,073 B2
• Time in Patent Office: Days
• US Class Current: 324/661
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2217/960755 Constructional details of capacitive touch and proximity switches
• CPC Class Codes: Y10T 29/49105 Switch making

Abstract

In a method for forming an in-molded capacitive sensing device a plastic film is provided, the plastic film comprising a first side and a second side. A capacitive sensor pattern is disposed on at least a portion of the second side, the capacitive sensor pattern including a region for facilitating electrical contact. A resin layer is printed over a portion of the capacitive sensor pattern such that access to the region for facilitating electrical contact is maintained. A plastic layer is injection molded onto a portion of the resin layer such that the capacitive sensor pattern becomes in-molded between the plastic film and the plastic layer while access to the region for facilitating electrical contact is maintained.

Claims

1. A method for forming an in-molded capacitive sensing device, said method comprising:

providing a plastic film comprising a first side and a second side;

disposing a capacitive sensor pattern on at least a portion of said second side, said capacitive sensor pattern including a region for facilitating electrical contact;

printing a resin layer over a portion of said capacitive sensor pattern such that access to said region for facilitating electrical contact is maintained; and

injection molding a plastic layer onto a portion of said resin layer such that said capacitive sensor pattern becomes in-molded between said plastic film and said plastic layer while access to said region for facilitating electrical contact is maintained.

2. The method as recited in claim 1, further comprising:

disposing a cosmetic design between said plastic film and said plastic layer, such that said cosmetic design is visible through an exterior surface of said in-molded capacitive sensing device.

3. The method as recited in claim 1, further comprising:

disposing a protective laminate sheet between said capacitive sensor pattern and said resin layer such that access to said region for facilitating electrical contact is maintained.

4. The method as recited in claim 1, wherein said disposing a capacitive sensor pattern on at least a portion of said second side comprises:

forming said capacitive sensor pattern using transparent conductive material.

5. The method as recited in claim 1, wherein said disposing a capacitive sensor pattern on at least a portion of said second side comprises:

disposing said capacitive sensor in multiple layers comprising at least two conductive layers and at least one dielectric layer.

6. The method as recited in claim 1, wherein said injection molding a plastic layer onto a portion of said resin layer comprises:

injection molding said plastic layer around core pins positioned such that an aperture is created through said injection molded plastic layer to said region for facilitating electrical contact.

7. The method as recited in claim 1, wherein said injection molding a plastic layer onto a portion of said resin layer comprises:

injection molding said plastic layer such that access to said region for facilitating electrical contact is provided in an extended edge region of said second side of said plastic film which is not covered by said injection molded plastic layer.

8. The method as recited in claim 1, wherein providing said plastic film further comprises:

configuring said plastic film to be removable from said in-molded capacitive sensing device subsequent to said injection molding.

9. A plastic embedded capacitive sensor comprising:

a plastic film comprising a first side and a second side;

an injection molded plastic layer; and

a capacitive sensor pattern embedded between said second side and said injection molded plastic layer such that access to a region of said capacitive sensor pattern is maintained for facilitating electrical contact with said capacitive sensor pattern.

10. The plastic embedded capacitive sensor of claim 9, further comprising:

a laminate layer disposed between said plastic film and said injection molded layer.

11. The plastic embedded capacitive sensor of claim 9, further comprising:

a cosmetic design disposed between said plastic film and said injection molded plastic layer, such that said cosmetic design is visible through an exterior surface of said plastic embedded capacitive sensor.

12. The plastic embedded capacitive sensor of claim 11, wherein said cosmetic design comprises:

a demarcation related to use of said capacitive sensor pattern.

13. The plastic embedded capacitive sensor of claim 9, further comprising:

a conductive film tail coupled to said capacitive sensor pattern and accessible for electrically coupling to said capacitive sensor pattern.

14. The plastic embedded capacitive sensor of claim 9, wherein said plastic film is configured for removal subsequent to manufacture of said plastic embedded capacitive sensor.

15. The plastic embedded capacitive sensor of claim 9, wherein said plastic film comprises a material which allows transmission of light.

16. The plastic embedded capacitive sensor of claim 9, wherein said capacitive sensor pattern comprises:

a clear conductive material.

17. The plastic embedded capacitive sensor of claim 9, wherein said region for facilitating electrical contact comprises:

an exposed electrical trace disposed on a portion of said second side which extends from said injection molded plastic layer.

18. The plastic embedded capacitive sensor of claim 9, wherein said region for facilitating electrical contact comprises:

an electrical trace accessible via an aperture molded into said injection molded plastic layer.

19. A process for creating a plastic embedded capacitive sensor, said process comprising:

providing a plastic film comprising a first side and a second side;

providing a capacitive sensor pattern;

providing an injection molded plastic layer such that said capacitive sensor pattern is embedded between said second side and said injection molded plastic layer; and

providing electrical coupling access to a region of said capacitive sensor pattern such that an electrical coupling with said capacitive sensor pattern is facilitated.

20. The method as recited in claim 19, further comprising:

providing said plastic embedded capacitive sensor within an electronic apparatus.