Abstract:
There is provided a haptic feedback device. The haptic feedback device includes a vibration member; a vibration element formed on the vibration member to vibrate the vibration member; and a mass member formed on the vibration member to adjust a oscillation frequency of the vibration member, wherein one surface of the mass member facing the vibration member is formed to have a curved shape.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority of Korean Patent Application No. 10-2011-0142688 filed on Dec. 26, 2011, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a haptic feedback device, and more particularly, to a haptic feedback device able to prevent a vibration member (for example, a vibration plate) from being deformed by an external shock. 
         [0004]    2. Description of the Related Art 
         [0005]    To increase user convenience, a touch input/output device (for example, a haptic feedback device) in which selection buttons are displayed on a screen has come into general use. 
         [0006]    In a haptic feedback device, a user may directly input signals using a fingertip or the like, allowing input signals to be conveniently input to a device for the control thereof, while the user visually confirms output information. 
         [0007]    A haptic feedback device may achieve savings in space, improved operability, and simplicity, and enable a user to easily interact with a device. Besides, a haptic feedback device may provide a satisfactory complimentary relationship with IT devices. Therefore, a haptic feedback device has been widely utilized as an input/output device for a guide device for providing users with information in public places (for example, train stations, hospitals, schools, and the like). 
         [0008]    Meanwhile, the haptic feedback device is used for providing notification as to whether input signals have been received or whether output signals have been output. 
         [0009]    The haptic feedback device includes a vibration element (for example, a piezoelectric element) and a vibration member vibrated by the vibration element. 
         [0010]    However, the vibration member provided in the haptic feedback device may be a thin plate member for improving vibration characteristics, and therefore, in the case that a shock is applied to the haptic feedback device (for example, if a user drops the haptic feedback device), the haptic feedback device may be easily deformed or broken. 
       SUMMARY OF THE INVENTION 
       [0011]    An aspect of the present invention provides a haptic feedback device that may prevent the deterioration of vibration characteristics due to an external shock (particularly, a drop shock). 
         [0012]    According to an aspect of the present invention, there is provided a haptic feedback device including: a vibration member; a vibration element formed on the vibration member to vibrate the vibration member; and a mass member formed on the vibration member to adjust a oscillation frequency of the vibration member, wherein one surface of the mass member facing the vibration member is formed to have a curved shape. 
         [0013]    The one surface of the mass member may be formed to have the curved shape having a smaller curvature than a radius of curvature formed when the vibration member is deformed by vibrations of the vibration element. 
         [0014]    The vibration member may include a first plate member to which the vibration element is fixedly attached; and a second plate member extended from the first plate member and housing the mass member. 
         [0015]    The second plate member may be extended from a side surface of the first plate member, and be formed to be bent in a direction perpendicular to the first plate member. 
         [0016]    The first plate member and the second plate member may be integrally formed by press processing. 
         [0017]    The haptic feedback device may further include a shock absorbing member formed between the vibration member and the mass member to prevent contact between the vibration member and the mass member. 
         [0018]    The shock absorbing member may be formed on one surface of the vibration member. 
         [0019]    The shock absorbing member may be formed with the mass member. 
         [0020]    One surface of the shock absorbing member maybe formed to have a curved shape. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0022]      FIG. 1  is a cross-sectional view showing a haptic feedback device according to a first embodiment of the present invention; 
           [0023]      FIG. 2  is a cross-sectional view showing the haptic feedback device of  FIG. 1  in an operating state; 
           [0024]      FIGS. 3 and 4  are cross-sectional views showing a haptic feedback device according to a second embodiment of the present invention; 
           [0025]      FIG.5  is a cross-sectional view showing a haptic feedback device according to a third embodiment of the present invention; and 
           [0026]      FIG. 6  is a perspective view showing a vibration member of the haptic feedback device of  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0027]    Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
         [0028]    The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the shapes and dimensions of elements maybe exaggerated for clarity, and the same reference numerals will be used throughout to designate the same or like elements. 
         [0029]      FIG. 1  is a cross-sectional view showing a haptic feedback device according to a first embodiment of the present invention,  FIG. 2  is a cross-sectional view showing the haptic feedback device of  FIG. 1  in an operating state,  FIGS. 3 and 4  are cross-sectional views showing a haptic feedback device according to a second embodiment of the present invention,  FIG. 5  is a cross-sectional view showing a haptic feedback device according to a third embodiment of the present invention, and  FIG. 6  is a perspective view showing a vibration member of the haptic feedback device of  FIG. 5 . 
         [0030]    A haptic feedback device  100  according to a first embodiment of the present invention will be described with reference to  FIGS. 1 and 2 . 
         [0031]    The haptic feedback device  100  according to the first embodiment of the present invention may include cases  102  and  104 , a vibration member  10 , a vibration element  20 , and a mass member  40 . The haptic feedback device  100  having the above-described configuration may be mounted in other portable electronic apparatuses such as a portable phone, a portable electronic dictionary, or the like. 
         [0032]    In addition, the haptic feedback device  100  is connected to an input/output device of a corresponding electronic apparatus to thereby transmit vibration signals to a user. However, the haptic feedback device  100  according to the embodiment of the present invention is not limited to the above-described portable electronic apparatuses, and may be installed in an automatic teller machine (ATM) including a touch screen, a subway route guidance system in a subway station, or the like. In addition, the haptic feedback device  100  may be mounted and used in other electronic apparatuses requiring the output of vibrations. 
         [0033]    The cases  102  and  104  may include an upper case  102  and a lower case  104 . The cases  102  and  104  may protect the haptic feedback device  100  against an external shock. For this, the cases  102  and  104  may be manufactured using a metal having impact resistance. However, to lighten the haptic feedback device  100 , the cases  102  and  104  may be manufactured using plastic. In this case, the plastic may include components able to increase impact resistance. 
         [0034]    The cases  102  and  104  may be mounted in an electronic apparatus in which the haptic feedback device  100  is mounted, so as to be separated from and connected to the electronic apparatus. Alternatively, at least a part of the cases  102  and  104  (for example, the upper case  102  or the lower case  104 ) may be integrally formed with a portable electronic apparatus (for example, a portable phone) in which the haptic feedback device  100  is mounted. In addition, the upper case  102  or the lower case  104 , or the upper case  102  and the lower case  104  may be a part of the portable electronic apparatus. 
         [0035]    In addition, the cases  102  and  104  may include an electrode for receiving electrical signals from the portable electronic apparatus. The electrode may be formed outside of the cases  102  and  104 , and supply current to the vibration element  20  mounted in the device. 
         [0036]    Meanwhile, the upper case  102  and the lower case  104  may both be connectable and separable. For example, the upper case  102  and the lower case  104  may be connected by nuts and bolts. Alternatively, the upper case  102  and the lower case  104  may be connected by a separate fitting structure (for example, protrusions and grooves). 
         [0037]    The vibration member  10  maybe manufactured to be a thin plate with a substantially rectangular cross section. However, the vibration member  10  maybe manufactured to have shapes other than the rectangular shape, as long as the vibration member  10  can be vibrated in a vertical direction. 
         [0038]    The vibration member  10  may be manufactured using a material having a predetermined level of elasticity. For example, the vibration member  10  may be formed of metal, plastic, or the like. In addition, in the vibration member  10 , a spring constant K may be determined so that the haptic feedback device  100  has a predetermined range of vibrational frequencies (100 to 300 Hz). For example, a length and a thickness of the vibration member  10  may be adjusted so that the haptic feedback device  100  has vibrational frequencies of 100 to 300 Hz. 
         [0039]    The vibration member  10  may be fixed to the cases  102  and  104 . Specifically, both ends of the vibration member  10  may be connected to the cases  102  and  104 . More specifically, both ends of the vibration member  10  may be fixed to the upper case  102  or the lower case  104 , or may be simultaneously fixed to the upper case  102  and the lower case  104 . 
         [0040]    Here, both ends of the vibration member  10  may be connected to the cases  102  and  104  through a welding method or a bolt fastening method. However, a connection method between the vibration member  10  and the cases  102  and  104  is not limited to the above-described methods, and may be changed within a range capable of being recognized by a person having ordinary skill in the art. 
         [0041]    Since the vibration member  10  mounted in the cases  102  and  104  has a predetermined level of elasticity as described above, the vibration member  10  may be vibrated in a vertical direction (a Z-axis direction, based on  FIG. 1 ) by external forces. For reference, the vibration member  10  may be contracted and extended for smooth vertical vibrations. However, a range of the contraction and extension of the vibration member may not be outside of a range of elastic deformation of the material constituting the vibration member  10 . 
         [0042]    The vibration element  20  may be fixed to the vibration member  10 . Specifically, the vibration element  20  may be adhered to the vibration member  10  by an adhesive. Here, the adhesive may be an epoxy resin or a resin which can be cured by UV light. In addition, the vibration element  20  may be fixed to the vibration member  10  in a mechanical structure. For this, a groove in which the vibration element  20  is fitted may be formed in the vibration member  10 . In addition, a protrusion for fixing a position of the vibration element  20  may be formed on the vibration member  10 . 
         [0043]    The vibration element  20  may be a piezoelectric element that can be freely contracted and extended according to electrical signals. For example, the vibration element  20  may be manufactured using PZT (Lead Zirconium Titanite Ceramic). The vibration element  20  configured as above may be contracted and extended according to the electrical signals to thereby generate vibrations in the vibration member  10 . 
         [0044]    The vibration element  20  maybe formed to be elongated in the longitudinal direction of the vibration member  10 . Specifically, the vibration element  20  may be disposed at a center of the vibration member  10  so as not to hinder vertical vibrations of the vibration member  10 . In addition, the vibration element  20  may be shorter than the vibration member  10 . 
         [0045]    The mass member  40  may be connected to the vibration member  10 . Specifically, the mass member  40  may be connected to the vibration member  10  at a point which coincides with a line segment C-C for dividing the vibration member  10  into two equal parts in an X-axis direction. The connection between the mass member  40  and the vibration member  10  may be carried out by a fastening member such as a bolt, or the like, or by an adhesive. Alternatively, the mass member  40  and the vibration member  10  may be connected through an auxiliary tool such as a clip, a clamp, or the like. 
         [0046]    The mass member  40  may have a predetermined mass, and reduce vibrational frequencies of a vibration generating device. For reference, the mass member  40  may be manufactured using a single material such as tungsten, nickel, or copper, or a mixed material containing at least one of tungsten, nickel, and copper. 
         [0047]    Meanwhile, according to the present embodiment, the mass member  40  may have a surface having a curved shape. Specifically, a first surface  42  of the mass member  40  which faces the vibration member  10  may have a curved shape. That is, the first surface  42  of the mass member  40  may have a curved shape having a radius R 1  with respect to an X-Z plane. Here, the radius R 1  may be smaller than a radius of curvature (R 2 ) formed when the vibration member  10  is bent by vibrations, as shown in  FIG. 2 . 
         [0048]    In this manner, the mass member  40  having the curved shape may not contact the vibration member  10  or collide with the vibration member  10  when the vibration member  10  vibrates (that is, when the vibration member  10  is bent and deformed). 
         [0049]    Accordingly, according to the present embodiment, when the vibration member  10  is vibrated in a vertical direction (a direction based on  FIG. 1 ) by the vibration element  20 , or an external shock, the vibration member  10  may not collide with the mass member  40 . 
         [0050]    In addition, even when the vibration member  10  collides with the mass member  40 , since the first surface  42  of the mass member  40  has the curved shape, a phenomenon in which the vibration member  10  is deformed due to contact with a part (for example, a corner) of the mass member  40  may not occur. That is, in the present embodiment, the vibration member  10  may uniformly contact the first surface  42  of the mass member  40 , and therefore a shock energy generated at the time of contact does not concentrate on a part of the vibration member  10 . 
         [0051]    Accordingly, the deformation of the vibration member  10  may not occur even at the time of contact between the vibration member  10  and the mass member  40 . 
         [0052]    In this manner, the haptic feedback device  100  according to the present embodiment may provide constant vibrational frequencies because the vibration member  10  is hardly deformed by a shock caused by external force. 
         [0053]    Next, a haptic feedback device according to a second embodiment of the invention will be described with reference to  FIGS. 3 and 4 . 
         [0054]    The haptic feedback device  100  according to the present embodiment differs from the haptic feedback device according to the first embodiment, in that the haptic feedback device  100  according to the second embodiment further includes a shock absorbing member  30 . 
         [0055]    The shock absorbing member  30  may be formed with the mass member  40  or the vibration member  10  as of  FIGS. 3 and 4 , and have a curved surface. For example, the shock absorbing member  30  may be formed on one surface (a surface facing the vibration member  10 ) of the mass member  40 , and a surface  32  facing the vibration member  10  may have a curved shape. Here, a radius of curvature (R 3 ) of the surface  32  may be smaller than or equal to the radius of curvature (R 2 , see  FIG. 2 ) formed when the vibration member  10  is deformed. 
         [0056]    In addition, the shock absorbing member  30  may be formed on one surface (a surface facing the mass member  40 ) of the vibration member  10 , and a surface  34  facing the mass member  40  may have a curved shape. However, it is unnecessary that the corresponding surface  34  has the curved shape. That is, the shock absorbing member  30  has an inclined surface whose angle of inclination is gradually reduced toward both ends of the vibration member  10  based on a connection point between the vibration member  10  and the mass member  40 . 
         [0057]    In the present embodiment configured as above, the vibration member  40  having a relatively high level of hardness does not need to have a curved surface, such that it may be effectively applied to the production of a small haptic feedback device. 
         [0058]    Next, a haptic feedback device according to a third embodiment of the present invention will be described with reference to  FIGS. 5 and 6 . 
         [0059]    The haptic feedback device  100  according to the present embodiment may differ from the haptic feedback device according to the above-described embodiments in terms of the shape of the vibration member  10 . 
         [0060]    The vibration member  10  according to the present embodiment may include a first plate member  12  and a second plate member  14 . 
         [0061]    The first plate member  12  may be formed as a thin plate, and may be a vibration member substantially vibrated in a vertical direction. Both ends of the first plate member  12  may be fixed to the cases  102  and  104 . The first plate member  12  may be formed of metal, plastic, or the like. In addition, the first plate member  12  may have a predetermined spring constant K. Here, the spring constant K of the first plate member  12  may be determined to be within a range in which the haptic feedback device  100  has vibrational frequencies of 100 to 300 Hz. 
         [0062]    A fastening hole for fastening the first plate member  12  and the cases  102  and  104  may be formed in the first plate member  12 . That is, the first plate member  12  may be fixed to the cases  102  and  104  through a fastening member (a bolt, a pin, or the like). 
         [0063]    In addition, the first plate member  12  may include a connection portion  16  connected to the second plate member  14 . The connection portion  16  may be extended from both side surfaces of the first plate member  12 , and may be formed near a point at which the first plate member  12  is divided into two equal parts in a longitudinal direction thereof. In addition, the side surface of the connection portion  16  may be a curved surface having a radius R 4 . The connection portion  16  having the above-described shape may minimize a load of the mass member  40  being concentrated on a part of the first plate member  12 . 
         [0064]    The second plate member  14  may be connected to the first plate member  12 . Specifically, the second plate member  14  may be integrally connected to the first plate member  12  through the connection portion  16 . More specifically, the second plate member  14  may be integrally formed with the first plate member  12  by press processing. The second plate member  14  may be bent in a direction perpendicular to the first plate member  12 . 
         [0065]    The second plate member  14  may have a predetermined mass so that the haptic feedback device  100  has a relatively low vibrational frequency. Alternatively, the second plate member  14  may have a shape capable of housing the mass member  40  having a predetermined mass. For example, the second plate member  14  may be firmly connected to the mass member  40  in such a manner that both ends of the second plate member  14  are bent in the same direction as depicted in  FIG. 6 . 
         [0066]    In addition, one surface  15  (a surface facing the first plate member  12 ) of the second plate member  14  may have a curved shape, and the radius of curvature of the curved surface may be smaller than the radius of curvature (R 2 , see  FIG. 2 ) formed when the vibration member  10  is deformed. 
         [0067]    In addition, a plurality of holes  18  may be formed in the second plate member  14 . The holes  18  may be formed at regular intervals in a longitudinal direction (an X-axis direction based on  FIG. 6 ) of the second plate member  14 , and a fastening member such as a bolt or the like may be fitted to the holes  18 . That is, the holes  18  may be used to fix the mass member  40  to the second plate member  14 . 
         [0068]    The mass member  40  may be connected to the second plate member  14 . Specifically, the mass member  40  may be forcedly fitted to the second plate member  14 , be attached to the second plate member  14  by an adhesive, or be connected to the second plate member  14  using a fastening member such as a bolt. The mass member  40  according to the present embodiment may have a size capable of being completely housed in a space formed by the second plate member  14 . That is, the mass member  40  may have a size so as not to protrude to the surface  15  of the second plate member  14 . 
         [0069]    Accordingly, according to the present embodiment, the first plate member  12  and the mass member  40  may not directly collide with each other when the vibration member  10  is vibrated. 
         [0070]    Meanwhile, although not shown, a shock absorbing member for reducing or blocking direct contact between the first plate member  12  and the second plate member  14  or between the first plate member  12  and the mass member  40  may be further formed in the space formed by the second plate member  14 . 
         [0071]    In the present embodiment configured as above, the vibration member  10  and the mass member  40  may be easily connected to each other, and contact between the vibration member  10  and the mass member  40  may be blocked without forming the curved surface on the mass member  40 . 
         [0072]    As set forth above, according to embodiments of the present invention, one surface of a mass member that may collide with a vibration member has a curved shape, and therefore the occurrence of a phenomenon in which the vibration member is deformed by contact between the vibration member and the mass member may be significantly reduced. 
         [0073]    Accordingly, according to embodiments of the present invention, vibrational frequencies of the haptic feedback device may be constantly maintained. 
         [0074]    While the present invention has been shown and described in connection with the embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.