Tactile actuator

Abstract

A tactile actuator, according to one embodiment, may comprise: a housing defining an accommodation space therein; an upper case for covering the upper part of the accommodation space; a vibration unit arranged inside the accommodation space; an upper elastic member connecting the upper side of the housing and the vibration unit; a lower elastic member for connecting the lower side of the housing and the vibration unit; and a coil for forming a magnetic field to drive the vibration unit, wherein one end of the upper elastic member may be fixed to a position on a side wall of the housing that is apart from the upper case.

1 . A tactile actuator comprising:
 a housing having an accommodation space;   a vibrator disposed in the accommodation space;   an elastic member configured to connect the housing and the vibrator; and   a coil configured to generate a magnetic field to drive the vibrator,   wherein the tactile actuator has a plurality of operation modes including a tapping mode, and   wherein, when a resonance frequency is 100 Hz or more and 170 Hz or less, if a waveform having a frequency of 20 Hz or less (greater than 0) is applied to the coil, a sum of impulse provided exceeds 3 mNs, so that a user can feel a tactile sense of tapping.   
     
     
         2 . The tactile actuator of  claim 1 ,
 wherein the vibrator comprises:   a mass body connected to the elastic member and having a magnetic property;   a magnetic portion provided at the center of a lower side of the mass body; and   a pole piece attached to a bottom surface of the magnetic portion.   
     
     
         3 . The tactile actuator of  claim 1 ,
 wherein, in the tapping mode, a cumulative impulse of the vibrator exceeds 3 mNs within an interval of 50 milliseconds (ms).   
     
     
         4 . The tactile actuator of  claim 1 ,
 wherein, in the tapping mode, a magnitude of an amplitude of a vibrating force of the vibrator varies over time and   a minimum time interval, in which a difference in height between peak points of the amplitude of the vibrating force of the vibrator is greater than 0.1 G, is greater than a minimum time in which a person distinguishes two stimuli at a fingertip.   
     
     
         5 . The tactile actuator of  claim 1 ,
 wherein the operation mode includes a normal vibration mode and a tapping mode,   when a square wave having a frequency of 20 Hz or less (greater than 0) is applied to the coil, the operation mode is a tapping mode, and when a sine wave having a frequency between 50 Hz and 170 Hz is applied to the coil, the operation is a normal vibration mode.   
     
     
         6 . The tactile actuator of  claim 5 ,
 wherein, when a sine wave having a frequency of 20 Hz or less (greater than 0) is applied, a vibration force of 0.01 G or less is generated, and   wherein, when a square wave having a frequency of 20 Hz or less (greater than 0) is applied, a vibration force of 0.1 G or more is generated.   
     
     
         7 . The tactile actuator of  claim 3 ,
 wherein, in the tapping mode, a magnitude of an amplitude varies for each cycle over time, and the magnitude of the amplitude for the first 20 ms has a value larger than that of the amplitude for the rest of the time, so that the user can sense an intermittent tapping which is different from a normal vibration.   
     
     
         8 . A tactile actuator comprising:
 a housing;   a vibrator elastically supported in the housing;   a coil configured to generate a magnetic field according to an applied current, the magnetic field being applied to the vibrator; and   a controller configured to operate the coil through a plurality of operation modes by controlling the frequency and waveform of the current to be applied to the coil,   wherein the plurality of operation modes includes a tapping mode,   wherein, in the tapping mode, a magnitude of an amplitude of a vibrating force of the vibrator varies over time.   
     
     
         9 . The tactile actuator of  claim 8 ,
 wherein, in the tapping mode, a minimum time interval, in which a difference in height between peak points of the amplitude of the vibrating force of the vibrator is greater than 0.1 G, is greater than a minimum time in which a person distinguishes two stimuli at a fingertip.   
     
     
         10 . The tactile actuator of  claim 9 ,
 wherein, when a resonance frequency of the tactile actuator is 100 Hz or more and 170 Hz or less, in the tapping mode, the controller applies a current having a frequency of 20 Hz or less (greater than 0) to the coil.