Patent Publication Number: US-11665456-B2

Title: Multi-function acoustic sensor

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2020-0125088, filed on Sep. 25, 2020, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     Example embodiments of the present disclosure relate to a multi-function acoustic sensor, and, more particularly, to a multi-function acoustic sensor which may be used multi-functionally according to various acoustic standards. 
     2. Description of Related Art 
     Acoustic sensors, which detect acoustic signals by converting mechanical movements into electrical signals, are utilized in apparatuses such as electronic apparatuses including microphones such as, for example, home appliances, image display devices, virtual reality devices, augmented reality devices, artificial intelligent speakers, automobiles, and ships, and apparatuses that distinguish external sound from internal sound. 
     To eliminate vibration effects from the acoustic signals, a physical method such as damping is used to eliminate the vibration, or a method for adding vibration absorbing agents or a mechanical correcting method for providing structural characteristics robust against the vibration is used. In the case of the mechanical method, vibration absorbing materials, or the like, are used to autonomously reduce the vibration, and thus, the acoustic sensor occupies a large volume. Thus, it is difficult to use such an acoustic sensor in a small device or module. 
     In the case of correcting an acoustic signal after vibration is detected by a separate structure, although the volume of an acoustic sensor is relatively smaller than that in the case of the physical method for vibration, the volume of the acoustic sensor is still large. Also, in this case, since correction is made by taking the characteristics of the original structure according to the vibration into consideration after checking the vibration with the separate structure, the case of the acoustic sensor is significantly affected by a change in the manufacturing process and complex computational operations are performed for the correction of the acoustic sensor. 
     SUMMARY 
     One or more example embodiments provide a multi-function acoustic sensor which may be implemented in a single case and may be used multi-functionally according to acoustic standards. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented example embodiments of the present disclosure. 
     In accordance with an aspect of an example embodiment, there is provided a multi-function acoustic sensor including: a plurality of sensors provided on a plate structure having a plurality of open spaces apart from each other, the plurality of sensors including a plurality of sensor elements respectively provided to overlap the plurality of open spaces; and a case having an inner space in which the plurality of sensors are provided, the case including: a first case surface on which the plurality of sensors are provided, the first case surface having at least one first hole, and a second case surface opposite to the first case surface, the second case surface having at least one second hole, wherein the at least one first hole and the at least one second hole form at least one path along which sound is transmitted and sensed through at least one of the plurality of open spaces of the plate structure. 
     The plate structure may include a bottom plate having the plurality of open spaces; and a plurality of supports which respectively extend from the bottom plate in a direction crossing the plurality of open spaces, and the plurality of sensor elements of the plurality of sensors may be respectively provided on the plurality of supports. 
     The plate structure may be a monolithic body. 
     The plate structure may include a plurality of individual plate structures each having one of the open spaces and one of the supports. 
     The multi-function acoustic sensor may further include a partition wall which is provided in the inner space of the case and spatially separates at least one of the plurality of sensors from another one of the plurality of sensors. 
     The first case surface may have a plurality of first holes respectively provided at positions corresponding to the plurality of sensors, a number of the plurality of first holes may be n, and a number of at least one second hole may be n−1 or less, or a number of at least one second hole is n or greater, and the plurality of first holes and the at least one second hole may form a plurality of paths along which sound is transmitted through the plurality of open spaces of the plate structure so that at least two of the plurality of sensors operate as acoustic sensors. 
     The plurality of first holes and the at least one second hole may be provided so that at least two of the plurality of sensors operate as directional acoustic sensors. 
     The multi-function acoustic sensor may further include a circuit substrate provided on the first case surface, and the circuit substrate may have third holes provided at positions respectively corresponding to all of the plurality of first holes, or at positions corresponding to a portion of the plurality of first holes, so that at least one of the plurality of sensors operates as an omni-directional acoustic sensor or a vibration sensor. 
     The at least one first hole and the at least one second hole may be respectively provided at positions corresponding to the plurality of sensors, and the at least one first hole and the at least one second hole may form a plurality of paths along which sound is transmitted through at least two of the plurality of open spaces of the plate structure so that at least two of the plurality of sensors operate as acoustic sensors. 
     The partition wall may spatially separate the plurality of sensors from each other. 
     The multi-function acoustic sensor may further include a circuit substrate which is provided on the first case surface and has third holes respectively provided at positions corresponding to a plurality of first holes of the first case surface or at positions corresponding to less than all of the plurality of first holes. 
     The first case surface may have a plurality of first holes and the second case surface may have a plurality of second holes, the plurality of first holes and the plurality of second holes may form a plurality of paths along which sound is transmitted through at least two of the plurality of open spaces of the plate structure so that at least two of the plurality of sensors operate as acoustic sensors, either the plurality of first holes or the plurality of second holes may be provided in portions of the first case surface and the second case surface, respectively, corresponding to at least one sensor of the plurality of sensors, the at least one sensor may operate as an omni-directional acoustic sensor, and the multi-function acoustic sensor may include at least two directional acoustic sensors and at least one omni-directional acoustic sensor. 
     The multi-function acoustic sensor may further include a circuit substrate which is provided on the first case surface and has third holes respectively provided at positions corresponding to the plurality of first holes or at positions corresponding to less than all of the plurality of first holes. 
     The first case surface may have a plurality of first holes and the second case surface may have a plurality of second holes, the plurality of first holes and the plurality of second holes may form a plurality of paths along which sound is transmitted through at least two of the plurality of open spaces of the plate structure so that at least two of the plurality of sensors operate as acoustic sensors, and neither the first hole or second hole may be provided on portions of the first case surface and the second case surface corresponding to at least one sensor of the plurality of sensors so that at least one of the plurality of sensors may operate as a vibration sensor, and the multi-function acoustic sensor may include a plurality of directional acoustic sensors and at least one vibration sensor. 
     The multi-function acoustic sensor may further include a circuit substrate which is provided on the first case surface and has third holes respectively provided at positions corresponding to a portion of the plurality of first holes. 
     The first case surface may have a plurality of first holes, and the multi-function acoustic sensor further may include a circuit substrate which is provided on the first case surface and has third holes respectively provided at positions corresponding to the plurality of first holes or at positions corresponding to less than all of the plurality of first holes. 
     The partition wall may be provided to spatially separate the plurality of sensors from each other, the first case surface may have a plurality of first holes, the second case surface may have a plurality of second holes, the multi-function acoustic sensor further may include a circuit substrate which is provided on the first case surface and has a plurality of third holes respectively provided at positions corresponding to the plurality of first holes or at positons corresponding to less than all of the plurality of first holes, the plurality of first holes, the plurality of second holes, and the plurality of third holes maybe provided so that at least one of the plurality of sensors operates as a directional acoustic sensor, and the plurality of first holes, the plurality of second holes, and the plurality of third holes may be provided such that at least one of the plurality of second holes does not correspond to a first hole, and at least one of the plurality of second holes does not correspond to a third hole, and one of the plurality of sensors may operate as an omni-directional acoustic sensor. 
     The first case surface may have a plurality of first holes, the plurality of first holes may be respectively provided at positions corresponding to the plurality of sensors, a number of the plurality of first holes may be n, and a number of the at least one second hole may be less than n, and the plurality of first holes and the at least one second hole may form the at least one path along which sound is transmitted through the at least one of the plurality of open spaces of the plate structure so that at least two of the plurality of sensors operate as acoustic sensors. 
     The multi-function acoustic sensor may further include a partition wall which is provided in the inner space of the case spatially separates at least one of the plurality of sensors from another sensor of the plurality of sensors. 
     A side wall of the case may have at least one atmospheric pressure adjusting hole which does not transmit sound pressure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain example embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    schematically shows a multi-function acoustic sensor according to an example embodiment; 
         FIG.  2    is a plan view schematically illustrating a first case surface of a case of  FIG.  1   ; 
         FIG.  3    schematically shows a multi-function acoustic sensor according to an example embodiment in which a circuit substrate having third holes formed at positions respectively corresponding to a plurality of first holes of a first case surface is further provided for the multi-function acoustic sensor of  FIG.  1   ; 
         FIG.  4    illustrates an operation of the multi-function acoustic sensor  FIG.  3   ; 
         FIG.  5    schematically shows a multi-function acoustic sensor according to an example embodiment in which a circuit substrate having a third hole formed at a position except for at least one of a position corresponding to at least one of a plurality of first holes of a first case surface is further provided for the multi-function acoustic sensor of  FIG.  1   ; 
         FIG.  6    illustrates an operation of the multi-function acoustic sensor  FIG.  5   ; 
         FIG.  7    schematically shows a multi-function acoustic sensor according to an example embodiment in which a circuit substrate having a third hole formed at a position except for at least one of a position corresponding to a plurality of first holes of a first case surface is further provided for the multi-function acoustic sensor of  FIG.  1   ; 
         FIG.  8    illustrates an operation of the multi-function acoustic sensor  FIG.  7   ; 
         FIGS.  9 ,  10 ,  11 ,  12 ,  13 ,  14 , and  15    schematically show multi-function acoustic sensors according to example embodiments; 
         FIG.  16    is a perspective view illustrating an example of a sensor which may be utilized in multi-function acoustic sensors according to various example embodiments; 
         FIG.  17    is a cross-sectional view taken along line I-I′ of  FIG.  16   ; and 
         FIGS.  18 ,  19 ,  20 ,  21 ,  22 , and  23    show various examples of electronic devices including multi-function acoustic sensors according to various example embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the example embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the example embodiments are merely described below, by referring to the figures, to explain aspects of the present disclosure. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. For example, the expression, “at least one of a, b, and c,” should be understood as including only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c. 
     Hereinafter, example embodiments will be described in more detail with reference to the accompanying drawings. Like reference numbers refer to like elements in the figures, and the size of each component in the drawings may be exaggerated for clarity and convenience of description. The example embodiments described below are merely examples, and it is possible to make various changes to the example embodiments. 
     Hereinafter, when an element is referred to as being provided, disposed, and the like, “above,” “on,” “below,” “under,” “on an upper side of,” “on a lower side of,” “on a right side of,” “on a left side of,” and the like, another element, the element may directly contact the other element, or another element may be provided between the element and the other element. The singular forms of terms include the plural forms of the terms unless the context clearly indicates otherwise. Further, when it is described that one part “includes” some elements, it will be understood to imply the inclusion of the stated elements but not the exclusion of any other elements, unless explicitly described to the contrary. The use of the term “the,” and similar referents, when modifying a term is to be construed to cover both the singular and the plural forms of the modified term. 
       FIG.  1    schematically shows a multi-function acoustic sensor  10  according to an example embodiment.  FIG.  2    is a plan view schematically illustrating a first case surface  11   a  of a case  11  of  FIG.  1   . 
     Referring to  FIGS.  1  and  2   , the multi-function acoustic sensor  10  according to an example embodiment may include a plurality of sensors  30 ,  40 , and  50 , and a case  11  having inner spaces for accommodating the plurality of sensors  30 ,  40 , and  50 . The plurality of sensors  30 ,  40 , and  50  may be supported by a plate structure  20  having a plurality of open spaces that are spaced apart from each other, and may be respectively disposed on the plate structure to overlap the plurality of open spaces. The case  11  may include a first case surface  11   a  which has one or more first holes  33 ,  43 , and  53  extending therethrough, and in which the plurality of sensors  30 ,  40 , and  50  are installed; a second case surface  11   b  which has one or more second holes  35  and  55  extending therethrough, and is provided opposite to the first case surface  11   a , and side walls  11   c  provided between the first case surface  11   a  and the second case surface  11   b . The first case surface  11   a , the second case surface  11   b , and the side walls  11   c  may be a housing defining an inner space in which the plurality of sensors  30 ,  40 , and  50  are provided. The one or more first holes  33 ,  43 , and  53 , and the one or more second holes  35  and  55  may be arranged to provide at least one path along which sound is transmitted and sensed through at least one of the open spaces of the plate structure  20 . 
       FIG.  1    and the following example embodiment show that the first, second, and third sensors  30 ,  40 , and  50  are provided in the inner space of the case  11 , but this is merely an example. The number of sensors may be four or more, and the number of first holes  33 ,  43 , and  53 , the number of second holes  35  and  55 , and a number of third holes  93   a ,  93   b , and  93   c , which are provided in a circuit substrate  90  described later, may change according to the number of sensors. 
     The plate structure  20  may include a bottom plate having a plurality of open spaces spaced apart from each other, and a plurality of supports which extend from the bottom plate in a direction crossing the open spaces. In other words, the plurality of supports may overlap the open spaces. Sensor elements  31 ,  41 , and  51  may be respectively provided on the plurality of supports. For example, as illustrated in  FIG.  16   , the bottom plate may have a structure including a bottom plate  71 , and a support  72  which is provided in an open space  71   a  of the bottom plate  71  and extends from the bottom plate  71  in a direction crossing the open space  71   a.    
     In the present example embodiment and following various example embodiments, the plate structure  20  may be formed as a single body, i.e., a monolithic body. That is, the bottom plate having the plurality of open spaces may be provided as a single body, and the supports may respectively extend from the bottom plate in the direction crossing the open spaces. In another example, instead of using the plate structure  20  formed as the single body, an array of a plurality of individual plate structures  21 ,  23 , and  25 , each of which has one open space and one support, is provided as illustrated in  FIG.  15   , and the sensor elements  31 ,  41 , and  51  are positioned in supports of the individual plate structures  21 ,  23 , and  25 , respectively. Accordingly, a structure may be achieved in which the plurality of sensors  30 ,  40 , and  50  are provided independently and are arranged in the inner spaces of the case  11 . 
     For example, the plurality of sensors  30 ,  40 , and  50  may be provided with a sensor  70  having a cantilever shape as illustrated in  FIGS.  16  and  17   . That is, the plurality of sensors  30 ,  40 , and  50  may have a cantilever structure shape. Here, each of the plurality of sensors  30 ,  40 , and  50  may be, for example, a pressure gradient micro-electromechanical system (MEMS) element and have its own directivity. 
     Although  FIG.  16    shows only one sensor, the plurality of sensors  30 ,  40 , and  50  may each have the structure shown in  FIG.  16   . The sensor elements  31 ,  41 , and  51  of the plurality of sensors  30 ,  40 , and  50  may be provided, for example, in a configuration as illustrated in  FIGS.  16  and  17   , or may have another configuration. This is merely an example, and embodiments are not limited thereto. 
     In the multi-function acoustic sensor  10  according to an example embodiment, when the number of the first holes  33 ,  43 , and  53  provided in the first case surface  11   a  of the case  11  being n, the number of second holes  35  and  55  provided in the second case surface  11   b  of the case  11  may be less than n, equal to n, or greater than n. Also, the first holes  33 ,  43 , and  53  and the second holes  35  and  55  may be provided to form a plurality of paths along which sound is transmitted through at least two of the open spaces of the plate structure  20  so that at least two of the plurality of sensors  30 ,  40 , and  50  operate as acoustic sensors. 
     For example, if the first holes  33 ,  43 , and  53  provided in the first case surface  11   a  of the case  11  are provided at positions corresponding to the plurality of sensors  30 ,  40 , and  50 , respectively, and the number of second holes  35  and  55  provided in the second case surface  11   b  of the case  11  is n−1, then at least two of the plurality of sensors  30 ,  40 , and  50  may operate as acoustic sensors. 
     Here, the multi-function acoustic sensor  10  according to an example embodiment may further include partition walls  15  and  17  which spatially separate at least one of the plurality of sensors  30 ,  40 , and  50  from the other sensors of the plurality of sensors  30 ,  40 , and  50 . For example, the partition walls  15  and  17  may be provided to spatially separate the plurality of sensors  30 ,  40 , and  50  from each other. 
     In the multi-function acoustic sensor  10  as illustrated in  FIGS.  1  and  2   , the partition walls  15  and  17  may be provided to spatially separate the plurality of sensors  30 ,  40 , and  50  from each other, the first holes  33 ,  43 , and  53  provided in the first case surface  11   a  of the case  11  may be provided at positions corresponding to the plurality of sensors  30 ,  40 , and  50 , respectively, and the number of second holes  35  and  55  provided in the second case surface  11   b  of the case  11  may be n−1. Accordingly, at least two of the plurality of sensors  30 ,  40 , and  50  may operate as directional acoustic sensors, and at least one sensor provided to correspond to only the first holes  33 ,  43 , and  53  may operate as an omni-directional acoustic sensor. 
     In a case where the multi-function acoustic sensor  10  is configured such that, among the plurality of sensors  34 ,  40 , and  50 , for example, the first and third sensors  30  and  50  disposed on both sides among the first to third sensors  34 ,  40 , and  50  are used as the directional acoustic sensors and the second sensor  40  disposed on the center is used as the omni-directional acoustic sensor, some of the first holes  33 ,  43 , and  53  provided in the first case surface  11   a  may have an elongated slit shape. Also, pads  37 ,  47 , and  57  for electrical connection with a printed circuit board (PCB) may be provided on the first case surface  11   a.    
       FIGS.  1  and  2    and following various example embodiments illustrate that the plurality of sensors  30 ,  40 , and  50  include the first, second, and third sensors  30 ,  40 , and  50 . However, this is merely an example, and the embodiments are not limited thereto. The embodiments may be variously changed according to the number of sensors and the multi-functional utilization of the sensors. 
     Here, the multi-function acoustic sensor  10  according to the example embodiment may further include a circuit substrate  90  on which the first case surface  11   a  of the case  11  is disposed as illustrated in  FIGS.  3 ,  4 ,  5 ,  6 ,  7 , and  8   , and third holes  93   a ,  93   c , and  93   b  may be provided in the circuit substrate  90  at positions corresponding to each of the plurality of first holes  33 ,  43 , and  53 , or at positions corresponding to less than all of the plurality of first holes  33 ,  43 , and  53 . 
       FIG.  3    shows a multi-function acoustic sensor  10  according to an example embodiment in which a circuit substrate  90  having the third holes  93   a ,  93   c , and  93   b  provided at the positions respectively corresponding to each of the plurality of first holes  33 ,  43 , and  53  of the first case surface  11   a  is further provided for the multi-function acoustic sensor  10  of  FIG.  1   .  FIG.  4    illustrates an operation of the multi-function acoustic sensor  10  of  FIG.  3   . 
     Referring to  FIGS.  3  and  4   , in a case where the circuit substrate  90  has the third holes  93   a ,  93   c , and  93   b  at the positions corresponding to the plurality of first holes  33 ,  43 , and  53  of the first case surface  11   a , respectively, the first and third sensors  30  and  50  may operate as directional acoustic sensors (e.g., D 1  and D 2 ), and the second sensor  40  may operate as an omni-directional acoustic sensor (e.g., OM), as in  FIG.  1    in which the circuit substrate  90  is not provided. 
       FIG.  5    schematically shows a multi-function acoustic sensor  10  according to an example embodiment in which a circuit substrate  90  having third holes  93   a  and  93   b  respectively provided at positions corresponding to the first holes  33  and  53  of the first case surface  11   a  is further provided for the multi-function acoustic sensor  10  of  FIG.  1   .  FIG.  6    illustrates an operation of the multi-function acoustic sensor  10  of  FIG.  5   . 
       FIG.  5    shows a case where the third holes  93   a  and  93   b  are provided at the positions corresponding to the first and third sensors  30  and  50 , respectively, and a third hole is not provided at the position corresponding to the second sensor  40 . In this case, as shown in  FIG.  6   , the first and third sensors  30  and  50  may operate as directional acoustic sensors (e.g., D 1  and D 2 ). Also, there is no hole through which the sound is transmitted from an external source to the second sensor  40 , and thus, the second sensor  40  may operate as a vibration sensor (e.g., VA). 
       FIG.  7    schematically shows a multi-function acoustic sensor according to an example embodiment in which a circuit substrate  90  having third holes  93   b  and  93   c  respectively provided at positions corresponding to the first holes  43  and  53  of the first case surface  11   a  is further provided for the multi-function acoustic sensor  10  of  FIG.  1   .  FIG.  8    illustrates an operation of the multi-function acoustic sensor  10  of  FIG.  7   . 
       FIG.  7    shows a case where the third holes  93   c  and  93   b  are provided at the positions corresponding to the second and third sensors  40  and  50 , respectively, and a third hole is not provided at the position corresponding to the first sensor  30 . In this case, as shown in  FIG.  8   , sound may be transmitted through only the second hole  35  provided in the second case surface  11   b  in the first sensor  30 , and sound may be transmitted through the third hole  93   c  of the circuit substrate  90  and the first hole  43  provided in the first case surface  11   a  in the second sensor  40 . Thus, the first and second sensors  30  and  40  may operate as omni-directional acoustic sensors (e.g., OM 1  and OM 2 ). Also, the third sensor  50  may operate as a directional acoustic sensor (e.g., D). 
     As known from  FIGS.  3  to  8   , the sensor functions of the multi-function acoustic sensor  10  according to an example embodiment may be variously changed by adjusting the number and positions of third holes  93   a ,  93   b , and  93   c  provided in the circuit substrate  90  on which the case  11  of the multi-function acoustic sensor  10  is disposed according to an example embodiment. 
     For example, as the number and positions of the third holes  93   a ,  93   b , and  93   c  provided in the circuit substrate  90  are adjusted, the directional acoustic sensor may be changed to operate as the omni-directional acoustic sensor, and the omni-directional acoustic sensor may be changed to operate as the vibration sensor. 
     The changing of the sensor functions by the adjustment of the number and positions of the third holes  93   a ,  93   b , and  93   c  provided in the circuit substrate  90  may also be applied to the multi-function acoustic sensor  10  of various example embodiments described with reference to the following  FIGS.  9  to  15   , and an example embodiment may be appropriately changed. 
       FIG.  9    shows a multi-function acoustic sensor  100  according to another example embodiment. Compared to the multi-function acoustic sensor  10  of  FIG.  1   , the multi-function acoustic sensor  100  of  FIG.  9    shows an example in which the first holes  33 ,  43 , and  53  provided in a first case surface  11   a , and second holes  35 ,  45 , and  55  provided in a second case surface  11   b  are provided at positions corresponding to a plurality of sensors  30 ,  40 , and  50 , respectively. That is, the second hole  45  is further provided at the position of the second case surface  11   b  corresponding to the second sensor  40  among the first, second, and third sensors  30 ,  40 , and  50 . In this case, all of the first, second, and third sensors  30 ,  40 , and  50  may operate as directional acoustic sensors. Also, as above described with reference to  FIGS.  3  to  8   , for the multi-function acoustic sensor  100  of  FIG.  9   , the circuit substrate  90  may be further provided, and the number and positions of the third holes  93   a ,  93   b , and  93   c  provided in the circuit substrate  90  may be adjusted, and thus all of the first, second, and third sensors  30 ,  40 , and  50  may operate as directional acoustic sensors, or at least one sensor may be changed to operate as an omni-directional acoustic sensor. 
       FIG.  10    shows a multi-function acoustic sensor  200  according to another example embodiment. 
     As illustrated in  FIG.  10   , first holes  33 ,  43 , and  53  of a first case surface  11   a  may be provided at positions corresponding to a plurality of sensors  30 ,  40 , and  50 , respectively. Based on the number of first holes  33 ,  43 , and  53  being n, the number of second holes of the second case surface  11   b  may be less than n. The first holes  33 ,  43 , and  53  and the second holes may be provided to form paths along which sound is transmitted through the open spaces of a plate structure  20 , so that at least two of the plurality of sensors  30 ,  40 , and  50  may operate as acoustic sensors. Also, an example embodiment may not have partition walls  15  and  17  that spatially separate the plurality of sensors  30 ,  40 , and  50 . 
     Compared to the multi-function acoustic sensor  10  of  FIG.  1   , the multi-function acoustic sensor  200  of  FIG.  10    shows an example in which the first holes  33 ,  43 , and  53  provided in the first case surface  11   a  are provided at positions corresponding to the plurality of sensors  30 ,  40 , and  50 , respectively, and a second hole  45  provided in the second case surface  11   b  is provided at a position corresponding to only one of the plurality of sensors  30 ,  40 , and  50 , and a partition wall for spatially separating the plurality of sensors  30 ,  40 , and  50  is not provided. For example, in a structure without a partition wall that spatially separates the first to third sensors  30 ,  40 , and  50  as described above, the first holes  33 ,  43 , and  53  of the first case surface  11   a  may be provided at the positions corresponding to the first to third sensors  30 ,  40 , and  50 , respectively, but the second hole  45  of the second case surface  11   b  may be provided at only the position corresponding to the second sensor  40 . Because the multi-function acoustic sensor  10  of  FIG.  10    does not include partition walls, the first holes  33 ,  43 , and  53  and the single second hole  45  may form a plurality of paths along which sound is transmitted and sensed through each of the open spaces of the plate structure  20 . In this case, all of the first to third sensors  30 ,  40 , and  50  may operate as directional acoustic sensors. 
       FIG.  11    shows a multi-function acoustic sensor  300  according to another example embodiment, and may be a modified example of  FIG.  10   . 
     As illustrated in  FIG.  11   , the multi-function acoustic sensor  300  includes a partition wall  17  for spatially separating first and second sensors  30  and  40  from a third sensor  50 , first holes  33 ,  43 , and  53  of a first case surface  11   a  provided at positions corresponding to the first to third sensors  30 ,  40 , and  50 , respectively, and a second hole  305  of a second case surface  11   b  provided to correspond to a side of the partition wall  17  in which the first and second sensors  30  and  40  are positioned. In this case, the first and second sensors  30  and  40  may operate as directional acoustic sensors, and the third sensor  50  may operate as an omni-directional acoustic sensor. 
     Also, in a case where a circuit substrate  90  is provided on a case  11  of the multi-function acoustic sensor  300  of  FIG.  11   , when third holes  93   a  and  93   c  are provided in the circuit substrate  90  at only positions corresponding to the first and second sensors  30  and  40  and are not provided at position corresponding to the third sensor  50 , the third sensor  50  may operate as a vibration sensor. 
     In the structure in which the first holes  33 ,  43 , and  53  provided in the first case surface  11   a  are provided at the positions corresponding to the plurality of sensors  30 ,  40 , and  50 , respectively, as illustrated in  FIGS.  10  and  11   , the number of sensors, which operate as the directional acoustic sensors among the plurality of sensors  30 ,  40 , and  50 , may be adjusted according to the number and positions of the second hole provided in the second case surface  11   b , whether or not the partition wall is provided, and the number of partition walls. The remaining sensors may be adjusted to operate as omni-directional acoustic sensors or vibration sensors by providing the circuit substrate  90  below the first case surface  11   a.    
       FIG.  12    shows a multi-function acoustic sensor  400  according to another example embodiment. Compared to the multi-function acoustic sensor  10  of  FIG.  1   , the multi-function acoustic sensor  400  of  FIG.  12    shows an example in which the second holes  35 ,  45 , and  55  provided in a second case surface  11   b  are provided at positions corresponding to a plurality of sensors  30 ,  40 , and  50 , respectively, but first holes  33  and  53  provided in a first case surface  11   a  are provided at only positions corresponding to some of the plurality of sensors  30 ,  40 , and  50 . For example, with respect to the first to third sensors  30 ,  40 , and  50  as illustrated in  FIG.  12   , the first holes  33  and  53  may be provided at only positions corresponding to the first and third sensors  30  and  50 , and may not be provided at a position corresponding to the second sensor  40 . In this case, the first and third sensors  30  and  50  may operate as directional acoustic sensors, and the second sensor  40  may operate as an omni-directional acoustic sensor. For the multi-function acoustic sensor  400  of  FIG.  12   , a circuit substrate  90  may be further provided, and the number and positions of third holes  93   a ,  93   b , and  93   c  provided in the circuit substrate  90  may be adjusted, and thus at least one of the first and third sensors operating as the directional acoustic sensor may be changed to operate as an omni-directional acoustic sensor. 
     Here, the multi-function acoustic sensors  10 ,  100 ,  200 ,  300 , and  400  according to the various example embodiments described above may have three or more directional acoustic sensors, and in this case, the first holes  33 ,  43 , and  53  and pads provided in the first case surface  11   a  may be modified as illustrated in  FIG.  13   . That is, a plurality of first holes  33 ,  43   a ,  43   b , and  53  provided in the first case surface  11   a  may have an elongated slit shape, and an arrangement of pads  37   a ,  37   b ,  57   a , and  57   b  for electrical connection may also be variously changed. According to the multi-function acoustic sensors  10 ,  100 ,  200 ,  300 , and  400  of various example embodiments utilizing the configuration shown in  FIG.  13   , a spatial acoustic sensor such as, for example, a 180 degree sensor or 360 degree sensor may be implemented by a combination of a plurality of directional acoustic sensors and at least one omni-directional acoustic sensor. 
       FIG.  14    shows a multi-function acoustic sensor  600  according to another example embodiment. Compared to the multi-function acoustic sensor  10  of  FIG.  1   , the multi-function acoustic sensor  600  of  FIG.  14    shows an example in which at least one atmospheric pressure adjusting hole  13 , which does not transmit sound pressure, is provided in a side wall  11   c  of a case  11 . At least one atmospheric pressure adjusting hole  13  may be provided in the side wall  11   c  of the case  11 . Based on the atmospheric pressure adjusting hole  13  being provided, the possibility of damage to cantilever portions of at least some of the plurality of sensors  30 ,  40 , and  50  may be reduced when sound is suddenly transmitted. The atmospheric pressure adjusting hole  13  may be provided in the side wall  11   c  of the case  11  for at least some or all of the plurality of sensors  30 ,  40 , and  50 . This atmospheric pressure adjusting hole  13  may be used in the multi-function acoustic sensors  100 ,  200 ,  300 , and  400  of the various example embodiments described above. 
     Here, the case where the circuit substrate  90  is provided on the first case surface  11   a  of the case  11  has been described and illustrated as an example, but the circuit substrate  90  may be provided on two or more surfaces of the case  11 . Also, the sensing functions of the multi-function acoustic sensors  10 ,  100 ,  200 ,  300 ,  400 , and  600  according to example embodiments may be adjusted according to the number and positions of the third holes provided in the circuit substrate  90 . 
     Also, in the case where at least one of the plurality of sensors  30 ,  40 , and  50  is configured to operate as a vibration sensor in the multi-function acoustic sensors  10 ,  100 ,  200 ,  300 , and  400  according to example embodiments, a logic circuit for the vibration sensor may be further provided. The logic circuit for the vibration sensor may be provided in the inner space of the case  11 , provided on the circuit substrate  90 , or the like. 
       FIG.  16    is a perspective view illustrating an example of a sensor  70  which may be utilized in the multi-function acoustic sensors  10 ,  100 ,  200 ,  300 ,  400 , and  600  according to various example embodiments.  FIG.  17    is a cross-sectional view taken along line I-I′ of  FIG.  16   . 
     Referring to  FIGS.  16  and  17   , the sensor  70  may include a sensor element  80  provided in a bottom plate  71  of a plate structure. An open space  71   a  may be formed in the bottom plate  71 , and a support  72  extends from the bottom plate  71  toward the open space  71   a . Here, one end of the support  72  is fixed to the bottom plate  71 , and the other end of the support  72  may be configured to move in an up and down direction (e.g., in a z-axis direction). For example, a silicone bottom plate may be used as the bottom plate  71 , but the example embodiment is not limited thereto. In addition, a bottom plate made of various materials may be used. 
     The sensor element  80  is provided on the support  72 . In particular, the sensor element  80  may include a first electrode  81  provided on one surface of the support  72 , a piezoelectric layer  83  provided on the first electrode  81 , and a second electrode  82  provided on the piezoelectric layer  83 . First and second terminals  81   a  and  82   a  electrically connected to the first and second electrodes  81  and  82  may be provided in the bottom plate  71 . 
     When external energy such as sound and pressure is input to the sensor element  80 , the piezoelectric layer  83  is deformed, and electric energy may be generated. For example, when sound generated from a sound source (S) is input to the sensor element  80 , the piezoelectric layer  83  is deformed, electric energy may be generated between the first and second electrodes  81  and  82 , and the electric energy may be output through the first and second terminals  81   a  and  82   a . Here, for example, when common voltage V com  is applied to the first terminal  81   a , an output signal  87  may be obtained through a readout circuit  85  connected to the second terminal  82   a.    
     The sensor  70  illustrated in  FIG.  16    is a sensor having a cantilever structure shape, and may have different output gains according to an input direction of external energy. That is, the sensor  70  may operate as a directional acoustic sensor having sensitives varying depending on the input direction of external energy. Also, the sensor may operate as an omni-directional acoustic sensor, or a vibration sensor. 
     The multi-function acoustic sensors  10 ,  100 ,  200 ,  300 ,  400 , and  600  according to the various example embodiments described above include three or more sensors having a cantilever structure shape and single case, and each of the sensors may be, for example, a pressure gradient MEMS element and may have directivity. Also, even when a MEMS device having a cantilever structure shape is provided as a sensor, each of the sensors may be changed into omni-directional acoustic sensors, directional acoustic sensors, or vibration sensors according to the type or number of three or more sound transmission trough-holes provided in the case and the circuit substrate. 
     The multi-function acoustic sensors  10 ,  100 ,  200 ,  300 ,  400 , and  600  according to the example embodiments described above may be utilized in all fields related to acoustic devices. The multi-function acoustic sensors  10 ,  100 ,  200 ,  300 ,  400 , and  600  may easily detect internal and external sound, be easily changed into omni-directional or directional microphones or vibration sensors in terms of functionality, correct the vibration, and easily remove the sound, and thus, may be usefully applied in various devices such as a television, a mobile device, an automobile, and a manufacturing device. Also, the increasing need for multi-functional acoustic sensors may be actively handled. 
       FIGS.  18  to  23    show various examples of electronic devices in which the multi-function acoustic sensors  10 ,  100 ,  200 ,  300 ,  400 , and  600  according to various example embodiments may be applied. 
     The multi-function acoustic sensors  10 ,  100 ,  200 ,  300 ,  400 , and  600  according to the example embodiments may be applied to various electronic devices such as a mobile phone or smart phone  1000  illustrated in  FIG.  18   , a tablet or smart tablet  1100  illustrated in  FIG.  19   , a notebook computer  1200  illustrated in  FIG.  20   , a television or smart television  1300  illustrated in  FIG.  21   , an internal microphone  1410  of a highly-vibrating automobile  1400  illustrated in  FIG.  22   , and an artificial intelligent speaker  1500  illustrated in  FIG.  23   . 
     According to the multi-function acoustic sensor of the example embodiment, the plurality of sensors may be used multi-functionally according to the acoustic standards, and without separately manufacturing cases for relevant functions, the functions may be obtained by the single case. 
     The sensor functions of the multi-function acoustic sensor according to the example embodiment may be variously changed by adjusting the number and positions of holes provided in the circuit substrate provided on the case of the multi-function acoustic sensor according to the example embodiment. 
     It should be understood that the example embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each example embodiment should typically be considered as available for other similar features or aspects in other example embodiments. While example embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.