Non-invasive skin sensor for long-term monitoring and method for fabricating the same
Embodiments relate to a non-invasive electronic device including at least one sensing unit capable of accurately monitoring a user's health condition for a long time such as a few weeks without malfunction while it is worn on the wearer's skin in a non-invasive manner and a method for fabricating the non-invasive electronic device. The non-invasive electronic device includes for example, a skin sensor device.
1. An electronic module for monitoring a skin condition, comprising:
a first passivation layer configured to be positioned closer to a skin surface;
an electronic circuit unit built on the first passivation layer, and including a plurality of interconnects made of a conductive material and at least one sensing unit including a semiconductor property material, wherein each sensing unit includes at least one type of sensing unit selected from the group consisting of: one or more temperature sensing units, one or more hydration sensing units, one or more photo sensing units, and one or more strain sensing units; and
a second passivation layer formed on the electronic circuit unit,
wherein each of the first passivation layer, the electronic circuit unit and the second passivation layer includes a plurality of through-holes, wherein at least some of the plurality of through-holes in each layer form respective hole patterns, and
wherein the respective hole patterns in the first passivation layer, the electronic circuit unit and the second passivation layer have corresponding planar patterns that align to form a continuous open channel when the first passivation layer, the electronic circuit unit and the second passivation layer are stacked.
2. The electronic module according to claim 1 , wherein the plurality of through-holes forming the respective hole patterns comprise a plurality of dumbbell through-holes,
wherein each dumbbell through-hole includes circular parts at two ends connected by an extended part, and
wherein the plurality of dumbbell through-holes are arranged in an interdigitated array such that a circular part of one dumbbell through-hole is adjacent to an extended part of a neighboring dumbbell through-hole.
3. The electronic module according to claim 2 , wherein each respective hole pattern further comprises a plurality of circular through-holes, and
wherein the circular through-holes are formed in regions surrounded by the dumbbell through-holes arranged in the interdigitated array.
4. The electronic module according to claim 1 , wherein of the respective hole patterns in the first passivation layer, the electronic circuit unit and the hole pattern of the second passivation layer are configured with different specifications to provide varying degrees of flexibility.
5. The electronic module according to claim 1 , wherein each temperature sensing unit includes:
a temperature responsive layer connected to a corresponding interconnect among the plurality of interconnects,
wherein the temperature responsive layer generates an electric current in response to temperature, and
wherein the temperature responsive layer is connected to be positioned on a same plane as the corresponding interconnect.
6. The electronic module according to claim 5 , wherein the temperature responsive layer includes through-holes forming a hole pattern partially corresponding to the respective hole patterns in the first passivation layer and the second passivation layer.
7. The electronic module according to claim 1 , wherein each hydration sensing unit includes:
a plurality of electrodes connected to a corresponding interconnect among the plurality of interconnects, wherein the plurality of electrodes include at least one first electrode and at least one second electrode; and
a hydration responsive layer formed on a surface of the plurality of electrodes,
wherein each of the plurality of electrodes and the hydration responsive layer includes through-holes that form an open channel when stacked upon each other, and
wherein the through-holes of the plurality of electrodes and the through-holes of the hydration responsive layer have a planar pattern corresponding to the planar patterns of the through-holes in the first passivation layer and the second passivation layer.
8. The electronic module according to claim 7 , wherein the each hydration sensing unit has a cantilever structure such that the first electrode extends from a first interconnect, and the second electrode extends from a second interconnect, and
wherein extended parts of the at least one first electrode and the at least one second electrode are arranged in an interdigitated array.
9. The electronic module according to claim 1 , wherein each photo sensing unit includes:
a photo responsive layer having two ends positioned on a surface of a corresponding interconnect among the plurality of interconnects,
wherein the photo responsive layer generates an electric current in response to light irradiation, and
wherein the photo responsive layer generates an electric current when a specific band of light is irradiated, or generates a different electric current when an intensity of the irradiated light changes.
10. The electronic module according to claim 9 , wherein a part of the second passivation layer formed at a sensing area of each photo sensing unit further includes at least one auxiliary through-hole.
11. The electronic module according to claim 10 , wherein each photo sensing unit further includes a capping layer formed at an interface between the part of the second passivation layer having the auxiliary through-hole and the photo sensing unit.
12. The electronic module according to claim 1 , wherein the each strain sensing unit includes:
an active layer having two ends positioned on a surface of a corresponding interconnect among the plurality of interconnects, wherein the active layer generates an electric current in response to strain of the electronic module.
13. The electronic module according to claim 12 , wherein the strain sensing unit further includes at least one of a first capping layer formed at an interface between the active layer and the first passivation layer, or a second capping layer formed at an interface between the active layer and the second passivation layer.
14. The electronic module according to claim 12 , wherein the electronic circuit unit includes a pair of the strain sensing units,
wherein a first strain sensing unit of the pair is positioned on the first passivation layer to sense x-axial strain, and
wherein a second strain sensing unit of the pair is positioned on the first passivation layer to sense y-axial strain.
15. A non-invasive electronic device comprising the electronic module of claim 1 , wherein the non-invasive electronic device comprises:
a skin attachable flexible patch configured to contact the first passivation layer,
wherein the flexible patch includes a plurality of through-holes, wherein at least some of the plurality of through-holes of the flexible patch form a patch hole pattern, and
wherein the patch hole pattern has a planar pattern corresponding to the respective hole patterns of the electronic module to form a perforated pattern when stacked with the electronic module.
16. The non-invasive electronic device according to claim 15 , wherein the plurality of through-holes of the flexible patch includes at least one specific through-hole that is different from other through-holes,
wherein a size of the specific through-hole is different from a size of the other through-holes of the electronic module, and
wherein one of the photo sensing units and one of the strain sensing units are built in the specific through-hole.
17. The non-invasive electronic device according to claim 16 , wherein the flexible patch further includes a supporter which extends from one side to an opposing side in the at least one specific through-hole to support the photo sensing unit.