Flexible conductive bonding
Examples are disclosed that relate to flexible electrical interconnects in electronic devices. One example provides a device including a flexible substrate, a conductive trace disposed on the flexible substrate, an electronic component mounted to the flexible substrate, a liquid metal interconnect bridging between a pad on the component and the trace on the flexible substrate, and an encapsulant covering the interconnect.
1. A device comprising:
a device portion configured to move during device use;
a flexible substrate located within the device portion configured to move during use;
a printed conductive trace disposed on the flexible substrate to permit signals to be carried across the device portion configured to move during device use;
an electronic component mounted to the flexible substrate at a location laterally offset along the substrate from the printed conductive trace;
a liquid metal interconnect bridging between a pad on the component and the trace on the flexible substrate; and
an elastomeric encapsulant covering the interconnect.
2. The device of claim 1 , wherein the electronic component is positioned within a slot cut into the flexible substrate, wherein a top surface of the electronic component is flush with a top surface of the flexible substrate, and wherein the pad is positioned on the top surface of the electronic component.
3. The device of claim 2 , wherein the slot is sized to match dimensions of the electronic component.
4. The device of claim 2 , wherein the slot has a rectangular shape with rounded cutouts at one or more corners.
5. The device of claim 1 , wherein the electronic component and the flexible substrate each contact a common side of the liquid metal interconnect.
6. The device of claim 1 , wherein the electronic component and the flexible substrate contact opposing sides of the liquid metal interconnect, and wherein the liquid metal interconnect is sandwiched between the electronic component and the substrate.
7. The device of claim 1 , wherein the liquid metal interconnect comprises a gallium alloy.
8. A method of manufacturing a device, the method comprising:
disposing a printed conductive trace on a surface of a flexible substrate;
mounting an electronic component to the surface of the substrate in a flexible region of the flexible substrate that is laterally offset along the substrate from the printed conductive trace;
applying a liquid metal interconnect extending between the electronic component and the trace to bridge between a pad on the electronic component and the trace on the flexible substrate; and
disposing an elastomeric encapsulant over the interconnect to encapsulate the interconnect.
9. The method of claim 8 , wherein mounting the electronic component comprises inserting the electronic component into a slot cut into the flexible substrate.
10. The method of claim 9 , wherein dimensions of the slot match dimensions of the electronic component.
11. The method of claim 9 , wherein the slot is larger than the electronic component and wherein corners of the slot protrude away from the electronic component.
12. The method of claim 9 , wherein, upon inserting the electronic component into the slot, a top surface of the electronic component is flush with a top surface of the flexible substrate.
13. The method of claim 8 , wherein mounting the electronic component comprises mounting the electronic component on top of the liquid metal interconnect.
14. The method of claim 8 , wherein mounting the electronic component comprises coupling the electronic component to the liquid metal interconnect via an elastic conductor disposed between the liquid metal interconnect and the pad of the electronic component, the electronic component contacting a first surface of the liquid metal interconnect and the flexible substrate contacting a second, opposing surface of the liquid metal interconnect.
15. The method of claim 8 , wherein applying the liquid metal interconnect comprises printing a gallium alloy over at least a portion of the pad on the electronic component and over at least a portion of the conductive trace.
16. A device comprising:
a device portion configured to move during device use;
a flexible substrate located within the device portion configured to move during use;
a printed conductive trace disposed on a surface of the flexible substrate to permit signals to be carried across the device portion configured to move during device use;
an electronic component mounted to the surface of the flexible substrate at a location laterally offset along the substrate from the printed conductive trace, the electronic component comprising a pad spaced from the printed conductive trace; and
an interconnect bridging between the pad and the printed conductive trace to contact the pad and the trace on a common side of the interconnect, the interconnect comprising a conductive path extending from a surface of the printed conductive trace.
17. The device of claim 16 , wherein the interconnect includes a liquid metal material.
18. The device of claim 16 wherein the interconnect comprises a gallium alloy.
19. The device of claim 16 , wherein the electronic component is positioned within a slot cut into the substrate, wherein a top surface of the electronic component is flush with a top surface of the flexible substrate, and wherein the pad is positioned on the top surface of the electronic component.
20. The device of claim 16 , wherein the electronic component is mounted to a top surface of the flexible substrate, and wherein the conductive trace is disposed on the top surface of the flexible substrate.