Low-pressure capacitive tactile sensor and method for fabricating the same

1. A low-pressure capacitive tactile sensor for measuring tactile pressures in a range of approximately 0.5 kPa to approximately 20 kPa, the sensor comprising:

a first flexible electrode layer comprising one or more thin film electrode layers positioned on a first flexible substrate;

a second flexible electrode layer comprising one or more second thin film electrode layers positioned adjacent on a second flexible substrate, wherein the second electrode layer is approximately parallel to the first electrode layer;

a micro-patterned, discontinuous, flexible, UV-curable in approximately 60 seconds or less, elastic nano-imprinted polymer dielectric layer positioned between the first electrode layer and the second electrode layer, wherein the first flexible substrate with the one or more first flexible electrode layer is laminated to a first side of the micro-patterned polymer dielectric layer, wherein the micro-patterned polymer dielectric layer is laminated to the second electrode layer, wherein the scale of a pattern of the micro-patterned discontinuous dielectric layer is 1-100 μm, and

a ground shielding layer disposed above the first flexible electrode layer and below the second flexible electrode layer of the capacitive tactile sensor respectively to minimize electromagnetic and capacitive interference,

wherein the pressure sensing range of the capacitive tactile sensor is approximately 0.5-20 kPa, the sensitivity is approximately greater than 0.12 pF/kPa.

2. The capacitive tactile sensor according to claim 1 , wherein the UV-curable elastic polymer comprises polyether, ester, alkenes, olefins, urethane, silicone with acrylate or epoxy as end groups, blend of vinyl silicone oil, silicone polymer with a H group, or combination thereof.

3. The capacitive tactile sensor according to claim 1 , wherein a thickness of the dielectric layer is less than approximately 0.5 mm.

4. The capacitive tactile sensor according to claim 1 , wherein a structure of the micro-patterned dielectric is a pattern of cubes, cylinders, cones, pyramids, prisms, hemispheres, domes, or a combination thereof.

5. The capacitive tactile sensor according to claim 1 , wherein the sensing range and the sensitivity of the capacitive tactile sensor are adjusted according to a dimension and pitch of the micro-patterned discontinuous dielectric layer.

6. A capacitive tactile sensor system for measuring tactile, pressures in a range of approximately 0.5 kPA to approximately 20 kPa, comprising including a plurality of the sensors of claim 1 arranged in an array of rows and columns.

7. The capacitive tactile sensor system according to claim 6 , wherein the first electrodes of each sensor arranged in a same column are connected to a common column line.

8. The capacitive tactile sensor system according to claim 7 , wherein the second electrodes of each sensor arranged in a same row are connected to a common row line.

9. The capacitive tactile sensor system according to claim 6 , wherein the structure of the micro-patterned dielectric is a pattern of cubes, cylinders, cones, pyramids, prisms, hemispheres, domes, or a combination thereof.

10. The capacitive tactile sensor system according to claim 6 , wherein the UV-curable elastic polymer comprises polyether, ester, alkenes, olefins, urethane, silicone with acrylate or epoxy as end groups, blend of vinyl silicon oil, silicone polymer with a H group, or a combination thereof.

11. The capacitive tactile sensor system according to claim 6 , wherein the sensing range and the sensitivity of the capacitive tactile sensor system are adjusted according to a dimension and pitch of the micro-patterned discontinuous dielectric layer.

12. The capacitive tactile sensor system according to claim 8 , further comprising row-column scanning circuitry to independently measure capacitance of each sensor.

13. A method for fabricating a capacitive tactile sensor according to claim 1 , comprising:

providing a UV-curable elastic polymer layer, the UV-curable elastic polymer layer having a curing time of approximately 60 seconds or less;

nanoimprinting the UV-curable elastomeric layer to form a micro-patterned discontinuous dielectric layer having a micro-pattern scale of approximately 1-100 μm;

UV curing the micro-patterned discontinuous dielectric layer;

providing a first flexible electrode layer and a second flexible electrode layer, wherein the first flexible electrode layer comprises one or more first flexible electrodes positioned on a first flexible substrate and the second flexible electrode layer comprises one or more second flexible electrodes positioned on a second flexible substrate;

laminating the first flexible electrode layer to a first side of the micro-patterned discontinuous dielectric layer to form a first electrode-dielectric laminate;

laminating the first electrode-dielectric laminate to the second flexible electrode layer;

positioning a ground shielding layer adjacent to each of the first flexible electrode layer and the second flexible electrode layer respectively.

14. The method according to claim 13 , wherein a thickness of the dielectric layer is less than 0.5 mm.

15. The method of claim 13 , wherein the nanoimprinting comprises a roll-to-roll nanoimprinting process using a mold having an inverse pattern of structures to be imprinted, the structures selected from one or more of cubes, cylinders, cones, pyramids, prisms, hemispheres, or domes.

16. The method according to claim 13 , wherein the nanoimprinting process is conducted at room temperature.

17. The method according to claim 13 , wherein the UV-curable elastic polymer comprises polyether, ester, alkenes, olefins, urethane, silicone with acrylate or epoxy as end groups, blend of vinyl silicone oil, silicone polymer with a H group, or combination thereof.