Apparatus and method of controlling stiffness of soft material

1. An apparatus of controlling a stiffness of a soft material hardened from a liquid state having viscosity into a solid state, comprising:

a soft material accommodating means including a chamber corresponding to a space in which the soft material having fluidity before being hardened is accommodated and a wall structure surrounding the chamber; and

a stimulus means configured to apply a stimulus to the soft material in the soft material accommodating means to generate a flow in the soft material,

wherein the wall structure includes a passing region through which the stimulus generated in the stimulus means passes and a blocking region through which the stimulus generated in the stimulus means is blocked, and

wherein a thickness of the wall structure in the passing region is relatively smaller than that of the wall structure in the blocking region.

2. An apparatus of controlling a stiffness of a soft material hardened from a liquid state having viscosity into a solid state, comprising:

a soft material accommodating means including a chamber corresponding to a space in which the soft material having fluidity before being hardened is accommodated and a wall structure surrounding the chamber;

a stimulus means configured to apply a stimulus to the soft material in the soft material accommodating means to generate a flow in the soft material; and

a coupling member interposed between the soft material accommodating means and the stimulus means,

wherein a width of the coupling member is smaller than that of the chamber, and

wherein a passing region to which the stimulus generated in the stimulus means is transferred and a blocking region through which the stimulus generated in the stimulus means is blocked are formed in the chamber, the passing region being a region that corresponds to the coupling member and the blocking region being a region that does not correspond to the coupling member.

3. The apparatus of controlling a stiffness of a soft material of claim 1 , wherein the stimulus means is a surface acoustic wave generator or an ultrasound transducer.

4. The apparatus of controlling a stiffness of a soft material of claim 1 , wherein the stimulus means is a surface acoustic wave generator including a substrate and an inter digital transducer (IDT) electrode formed on the substrate.

5. The apparatus of controlling a stiffness of a soft material of claim 1 , wherein the wall structure of the soft material accommodating means is formed of polydimethylsiloxane (PDMS).

6. The apparatus of controlling a stiffness of a soft material of claim 4 , wherein the soft material accommodating means is attached to the substrate.

7. The apparatus of controlling a stiffness of a soft material of claim 4 , wherein an interval between one IDT finger and another one adjacent IDT finger is constant.

8. An apparatus for controlling a stiffness of a soft material hardened from a liquid state having viscosity into a solid state, the apparatus comprising:

a soft material accommodating chamber formed of a wall structure and having a space in which the soft material having fluidity before being hardened is accommodated; and

a stimulus generator configured to apply a stimulus to the soft material in the soft material accommodating chamber to generate a flow in the soft material,

wherein the wall structure includes a passing region through which the stimulus generated in the stimulus means passes and a blocking region through which the stimulus generated in the stimulus means is blocked, and

wherein a thickness of the wall structure in the passing region is relatively smaller than that of the wall structure in the blocking region.