Abstract: Provided is a strain sensor. The strain sensor according to embodiments of the inventive concept includes a flexible substrate, rigid patterns on the flexible substrate, the rigid patterns including a first pattern and a second pattern spaced apart from the first pattern in a first direction, a first electrode on the first pattern, a second electrode on the second pattern, the second electrode being spaced apart from the first electrode, and a piezoresistive layer connecting the first electrode and the second electrode. Here, each of the rigid patterns may have a stiffness greater than that of the flexible substrate.

Abstract: Provided is an electrostatic drive switch, which includes a source plate to which a voltage for driving the electrostatic drive switch is applied and a drain electrode spaced apart from the source plate. The source plate includes a source electrode and an elastic part connected to the source electrode, and a first material and a second material having lower hardness than the first material are provided on the source electrode. When the source electrode and the drain electrode are electrically connected to each other by the voltage, the second material is brought into contact with the drain electrode by the elastic part after the first material is brought into contact with the drain electrode by the elastic part.

Abstract: Provided is an electrostatic drive switch, which includes a source plate to which a voltage for driving the electrostatic drive switch is applied and a drain electrode spaced apart from the source plate. The source plate includes a source electrode and an elastic part connected to the source electrode, and a first material and a second material having lower hardness than the first material are provided on the source electrode. When the source electrode and the drain electrode are electrically connected to each other by the voltage, the second material is brought into contact with the drain electrode by the elastic part after the first material is brought into contact with the drain electrode by the elastic part.

Abstract: The present invention relates to a direction-controllable drug injection catheter. According to the present invention, provided is the catheter extending along a central axis “A” including a drug injection part in which a drug injection channel has been formed; a channel opening and closing means which opens and closes the drug injection channel; and a steering structure which is rotationally asymmetric with respect to the central axis “A” and varies according to a pressure change of the drug injection channel for the purpose of steering.

Abstract: The present invention relates to a direction-controllable drug injection catheter. According to the present invention, provided is the catheter extending along a central axis “A” including a drug injection part in which a drug injection channel has been formed; a channel opening and closing means which opens and closes the drug injection channel; and a steering structure which is rotationally asymmetric with respect to the central axis “A” and varies according to a pressure change of the drug injection channel for the purpose of steering.