Capacitive force sensor and method for preparing the same
The present disclosure relates to a force sensor including a first substrate, a first electrode installed in a pattern on an upper surface of the first substrate, a second substrate disposed above and spaced apart from the first substrate, a second electrode installed in a pattern on a lower surface of the second substrate, facing the first electrode, and a dielectric interposed between the first substrate and the second substrate, wherein the dielectric includes a first dielectric surrounding an outside of the second electrode, and a pressure rib connecting the first dielectric to the first electrode, and a method for preparing the same, and shows a remarkably superior effect to related art, in terms of capacitance, interactivity and durability.
1. A method for forming a force sensor, comprising:
a) stacking a first electrode on a first substrate;
b) stacking a second electrode on a second substrate;
c) forming a first dielectric and a pressure rib on the second electrode to prepare an upper body of the force sensor;
d) forming a second dielectric on an upper surface of the first electrode to prepare a lower body of the force sensor; and
e) bonding the upper body of the force sensor and the lower body of the force sensor, wherein the first dielectric, the pressure rib, and the second dielectric include a polymer dielectric composition comprising polymeric elastomer, and the polymeric elastomer is at least one selected from silicone-based resin, urethane-based resin, isoprene-based resin, fluoro-based resin, styrene-butadiene rubber, chloroprene rubber, acrylonitrile copolymer, and acrylate rubber, and wherein the polymer dielectric composition comprises a conductive filler a ceramic filler, an organic metal compound, or their mixtures,
wherein in the polymeric elastomer, the conductive filler is at least one selected from metal particles, singlewalled carbon nanotubes, multi-walled carbon nanotubes, graphene, graphite, carbon black, carbon fibers, and fullerene,
wherein the ceramic filler is metal oxide, silicate, boride, carbide, nitride, perovskite, or their mixtures, and
wherein the organic metal compound is a compound in which at least one type of metal selected from copper, zinc, and nickel is bonded to at least one type of organic matter selected from phthalocyanine, uranine, and rhodamine.
2. The method for preparing a force sensor according to claim 1 , wherein the first dielectric and the pressure rib are formed using an integral mold or a composite mold made up of multiple separate parts.
3. The method for preparing a force sensor according to claim 2 , wherein the pressure rib is formed using the mold after the first dielectric is prepared.
4. The method for preparing a force sensor according to claim 2 , wherein the mold is fixed using an adhesive tape.
5. The method for preparing a force sensor according to claim 1 , wherein the pressure rib is formed as a first pressure rib, a second pressure rib, or a plurality of pressure ribs.
6. The method for preparing a force sensor according to claim 2 , wherein a coating thickness of the pressure rib is thicker than a thickness of the surface of the mold by 5 to 100 μm.
7. The method for preparing a force sensor according to claim 2 , wherein a detaching jig is used to separate the first dielectric or the pressure rib from the mold.
8. The method for preparing a force sensor according to claim 1 , wherein the step e) is performed by any one method selected from:
a first method which bonds the upper body of the force sensor and the lower body of the force sensor with a thermal adhesive tape or a double-sided tape on both edges of the first substrate and the second substrate;
a second method which assembles the upper body of the force sensor with the lower body of the force sensor by performing plasma etching on a lower surface of the upper body of the force sensor and an upper surface of the lower body of the force sensor;
a third method which disposes the lower body of the force sensor and the upper body of the force sensor such that a part of an end of the pressure rib of the upper body of the force sensor is embedded in a lower body of the second dielectric, and assembles and cures them;
a fourth method which forms a pressure rib for adhesion having a cross sectional area 1.1 to 10 times wider than a cross sectional area of the pressure rib of the upper body of the force sensor on an upper surface of the lower body of the force sensor, and assembles the upper body of the force sensor with the lower body of the force sensor; and
a fifth method which assembles the upper body of the force sensor with the lower body of the force sensor with a double-sided tape, a thermal adhesive tape, or a polymer adhesive stacked between the upper body of the force sensor and the lower body of the force sensor.
9. The method for preparing a force sensor according to claim 1 , wherein the first substrate and the second substrate are a polyimide film, a polyethylene terephthalate film, or at least one selected from silicone-based, polystyrene-based, polyamide-based, polyurethane-based, polyepoxy-based, polyacryl-based, polyester-based and polyolefin-based polymeric elastomers, or their mixtures.
10. The method for preparing a force sensor according to claim 1 , wherein the first electrode and the second electrode are at least one selected from gold, silver, copper, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, graphene, a metal nanowire, and elastomer containing a conductive filler.
11. The method for preparing a force sensor according to claim 1 , wherein the metal oxide is at least one selected from zirconium oxide, tantalum oxide, tin oxide, niobium oxide, titanium oxide, rare earth oxide, antimony oxide, vanadium oxide, iron oxide, strontium oxide, copper oxide, titanium oxide, zinc oxide, niobium oxide, tantalum oxide, yttrium oxide, CaTiO 3 , MgZrSrTiO 6 , MgTO 3 , MgAl 2 O 4 , BaZrO 3 , BaTiO 3 , BaSnO 3 , BaNb 2 O 6 , BaTa 2 O 6 , BaSrTiO 3 , WO 3 , MnO 2 , SrZrO 3 , TiO 2 , ZnO, SnTiO 4 , ZrTiO 4 , CaZrO 3 , CaSnO 3 , CaWO 4 , MgTa 2 O 6 , MrZrO 3 , La 2 O 3 , CaZrO 3 , MgSnO 3 , MgNb 2 O 6 , SrNb 2 O 6 , MgTa 2 O 6 , and Ta 2 O 3 , and
the silicate is at least one selected from Na 2 SiO 3 , Li 4 SiO 4 , BaTiSi 3 O 9 , ZrSiO 4 , CaMgSi 2 O 6 , and Zn 2 SiO 4 .
12. The method for preparing a force sensor according to claim 1 , wherein the conductive filler, the ceramic filler, or the organic metal compound further comprises a dispersant of the following Formula 1:
CX 3 (CX 2 ) n -Y [Formula 1]
where X is H or F,
Y is H, SH, NH 2 , OH, COOH, or SiR 1 R 2 R 3 ,
n is an integer of from 1 to 30, and
the R 1 , R 2 and R 3 are the same or different, and are H, F, Cl, Br, an alkyl group with 1 to 10 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, an alkenyl group with 1 to 10 carbon atoms, an alkyne group with 1 to 10 carbon atoms, an aryl group with 1 to 30 carbon atoms, a cyclo alkyl group with 1 to 30 carbon atoms, or a cyclo alkenyl group with 1 to 30 carbon atoms.