Patent Publication Number: US-2011072673-A1

Title: Tilt sensor

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 98133043, filed on Sep. 29, 2009. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a sensor, and particularly to a tilt sensor. 
     2. Description of Related Art 
     In general, most tilt sensors in the market only have two-phase sensing abilities, i.e. only being able to sense two tilt directions. Besides, the size of tilt sensors is usually large. Since consuming electronic products, for example, mobile phones focus on being light, slim, and compact, the conventional tile sensors have difficulty being applied therein. 
     Besides, when using tilt sensors having four-phase sensing abilities (being able to sense directions of up, down, left and right), two sets of two phase sensors are usually required, such that the fabrication cost, the size, and fabrication processes thereof can not be reduced effectively. 
     Hence, how to design a kind of tilt sensors that are tiny, have low cost and are suitable for being applied in consuming electronic products which are light, slim and have low cost has become an essential topic in the industry. 
     SUMMARY OF THE INVENTION 
     The invention relates tilt sensor which is capable of sensing a plurality of tilt directions and has advantages of thinness, having low cost, and being fabricated easily. 
     The invention provides a tilt sensor includes a body, a plurality of metal pad pairs, and a moving element. The body is suitable for tilting in a plurality of tilt directions and has a movement region which has a plurality of corners. The metal pad pairs are respectively located in at least a portion of the corners. The moving element is located in the movement region. When the body tilts towards one of the tilt directions, the moving element moves to one of the corners along the tilt direction of the body and physically contacts with the metal pad pair located in the corner, such that the metal pads of the metal pad pair are electrically connected with each other via the moving element. 
     In an embodiment of the invention, the movement region is a square movement region and the square movement region has four corners. 
     In an embodiment of the invention, the metal pad pairs are respectively disposed in each of the corners of the square movement region. 
     In an embodiment of the invention, the metal pad pairs are respectively disposed in three of the corners. 
     In an embodiment of the invention, the moving element is a metal ball. 
     In an embodiment of the invention, a size of the metal ball is larger than 0.1 mm and smaller than or equal to 0.5 mm. 
     In an embodiment of the invention, the body has a substrate and a housing. The housing is disposed on the substrate and has a recess structure to define the movement region, and each of the metal pad pairs is disposed on the substrate. 
     In an embodiment of the invention, the circuit substrate is a printed circuit board. 
     In an embodiment of the invention, the metal pads of the metal pad pairs of the tilt sensor are electrically connected with each other via the moving element which moves to different corners. Thus, the tilt direction of the tilt sensor is able to be determined by a simple tilt sensing function. Besides, the structure of the tilt sensor is also fabricated easily. Moreover, a size of the moving element is larger than 0.1 mm and smaller than or equal to 0.5 mm, such that the thickness of the tilt sensor is effectively reduced. 
     In order to make the aforementioned and other features and advantages of the invention more comprehensible, several embodiments accompanied with figures are described in detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a schematic diagram showing operations of a tilt sensor sensing various tilt directions according to the first embodiment of the invention. 
         FIG. 2  is a schematically cross-section view of  FIG. 1  along line AA&#39;. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
       FIG. 1  is a schematic diagram showing operations of a tilt sensor sensing various tilt directions according to the first embodiment of the invention.  FIG. 2  is a schematically cross-section view of  FIG. 1  along line AA′. Referring to both  FIG. 1  and  FIG. 2 , the tilt sensor  100  includes a body  110 , a plurality of metal pad pairs  122 ,  124 ,  126  and  128 , and a moving element  130 . The body  110  is suitable for tilting in a plurality of tilt directions P 1 , P 2 , P 3  and P 4 . The metal pad pairs  122 ,  124 ,  126  and  128  and the moving element  130  are in the body  110 . 
     The body  110  has a movement region  112  which has a plurality of corners  112   a ,  112   b ,  112   c  and  112   d . In the embodiment, the movement region  112  is a square movement region, which is used as an example to illustrate the concept of the invention. Thus, the movement region  112  has four corners  112   a ,  112   b ,  112   c  and  112   d . However, in another embodiment, the shape of the movement region  112  may be other polygons such as a regular pentagon, a regular hexagon or a regular n-sided polygon, where n is a positive integer greater than 4, and thus the movement region  112  has the number of corners corresponding to the shape thereof. 
     In the embodiment, the body  110  has a substrate  114  and a housing  116  as shown in  FIG. 2 . The housing  116  is disposed on the substrate  114  and has a recess structure  116   a  to define the movement region  112 . Specifically, the housing  116  may be formed through injection molding or punching molding, and the substrate  114  is, for example a printed circuit board. After completing the fabrication of the housing  116 , the housing  116  and the substrate  114  are sealed together by an encapsulating material or related bonding techniques, such that the body  110  is formed. 
     The metal pad pairs  122 ,  124 ,  126  and  128  are respectively located in at least a portion of the corners  112   a ,  112   b ,  112   c  and  112   d  as shown in  FIG. 1 . When the shape of the movement region  112  is designed as another polygon, the number of the metal pad pairs may be adjusted correspondingly to meet actual requirements. Specifically, four metal pad pairs are used and the movement region  112  is a square movement region in the embodiment. The aforementioned embodiment is only used as an example, but not to limit the invention. In another embodiment, the number of the metal pad pairs may be three, and the metal pad pairs are, for example located in the corners  112   a ,  112   b  and  112   d  of the movement region  112 . Related description will be illustrated in detail below. In the embodiment, the metal pad pairs  122 ,  124 ,  126  and  128  are disposed on the substrate  114  and respectively located in the four corners  112   a ,  112   b ,  112   c  and  112   d  of the movement region  112  as shown in  FIGS. 1 and 2 . 
     The moving element  130  is located in the movement region  112 . When the body  110  tilts towards one of the tilt directions, e.g. the tilt direction P 1 , the moving element  130  moves to the corner  112   a  along the tilt direction P 1  of the body  110  and physically contacts with the metal pad pair  122  in the corner  112   a , such that the metal pads of the metal pad pair  122  are electrically connected with each other via the moving element  130 . Similarly, when the body  110  tilts towards the tilt direction P 2 , the moving element  130  moves to the corner  112   b  along the tilt direction P 2 , and physically contacts with the metal pad pair  124  in the corner  112   b , such that the metal pads of the metal pad pair  124  are electrically connected with each other via the moving element  130 . Thus, the movement of the moving element  130  when the body  110  tilts towards the tilt directions P 3  and P 4  can be referred to the above description. In the embodiment, the moving element  130  is, for example a metal ball. A size of the metal ball is substantially larger than 0.5 mm and smaller than or equal to 0.1 mm. 
     Moreover, in order to specifically illustrate a sensing function and operations of the tilt sensor of the invention, detailed description is provided below with reference to  FIG. 1 . 
     First,  FIG. 1  is a schematic diagram showing the moving element  130  moves to various positions corresponding to different tilt directions P 1 , P 2 , P 3  and P 4  when the tilt sensor  100  is disposed on a horizontal plane, for example. For example, when the body  110  tilts downward in the tilt direction P 1 , the moving element  130  in the movement region  112  moves towards the corner  112   a  due to gravity, such that state  1  of  FIG. 1  is achieved. At this time, since the moving element  130  moves to the metal pad pair  122  in the corner  112   a  and physically contacts with the metal pad pair  122 , the metal pads of the metal pad pair  122  are electrically connected with each other via the moving element  130 , wherein the moving element  130  has conductivity. Thus, the tile direction of the tilt sensor  100  is able to be determined as the tilt direction P 1  according to the conducting state of the metal pad pair  122 . 
     Similarly, when the body  110  tilts downward in the tilt direction P 2 , the moving element  130  in the movement region  112  moves towards the corner  112   b  due to gravity, such that state  2  of  FIG. 1  is achieved. At this time, since the moving element  130  moves to the metal pad pair  124  in the corner  112   b  and physically contacts with the metal pad pair  124 , the metal pads of the metal pad pair  124  are electrically connected with each other (e.g. electrically conducted). Thus, the tile direction of the tilt sensor  100  is able to be determined as the tilt direction P 2  based on the conducting state of the metal pad pair  124 . 
     Similarly, when the body  110  tilts downward in the tilt directions P 3  and P 4 , the moving element  130  in the movement region  112  moves towards the corners  112   c  and  112   d  accordingly due to gravity, such that state  3  and  4  of  FIG. 1  are respectively achieved. Specifically, at states  3  and  4 , the moving element  130  respectively moves to the metal pad pair  126  in the corner  112   c  and the metal pad pair  128  in the corner  112   d , and physically contacts with the metal pad pairs  126  and  128  accordingly. Thus, the metal pads of the metal pad pair  126  and the metal pads of the metal pad pair  128  are electrically connected with each other via the moving element  130  (e.g. electrically conducted). Hence, the tile direction of the tilt sensor  100  is able to be determined as the tilt direction P 3  or P 4  based on whether the metal pad pair  126  or the metal pad pair  128  is conducted. 
     From the above, the tilt direction of the tilt sensor  100  is able to be deduced based on which one of the metal pad pair  122 ,  124 ,  126  and  128  is conducted. Besides, since the size of the metal ball is substantially larger than 0.1 mm and smaller than or equal to 0.5 mm, the thickness of the tilt sensor  100  is effectively reduced to 0.8 mm or even less. 
     In an embodiment, the number of the metal pad pairs may be three, and the metal pad pairs are, for example located in the corners  112   a ,  112   b  and  112   d  of the move region  112 . Hence, the title direction of the tilt sensor is able to be sensed based on the conducting states of the three metal pad pairs respectively corresponding to the three tilt directions P 1 , P 2  and P 4 . 
     When all of the three metal pad pairs are not at conducting states, the tilt direction of the tilt sensor  110  is deduced as the tilt direction P 3 . Thus, the number of the metal pad pair can be appropriately adjusted based on design demands, and the invention is not limited thereto. 
     It should be noted that, the tilt sensor  100  placed on a horizontal plane and sensing various tilt directions is only used as an example. The tilt sensor  100  also could be used to sense various rotation directions on a vertical plane. Besides, the tilt sensor  100  could be designed as an intelligent orientation sensor in a digital camera which recognizes when the camera is rotated from horizontal to vertical. For example, at state  3 , the tilt sensor  200  is regarded as being placed on a vertical plane, and then the moving element  130  moves to the corner  112   c  due to gravity and physically contacts with the metal pad pair  126 , such that the metal pads of the metal pad pair  126  are electrically connected with each other (e.g. electrically conducted). At this time, the tilt direction of the tilt sensor  100  is determined as a vertical direction. Then, when the tilt sensor  100  is rotated by 90, 180 and 270 degree in a clockwise direction parallel to the vertical plane, the moving element  130  moves to the corners  112   d ,  112   a  and  112   b  accordingly so that the metal pad pairs  128 ,  122  and  124  are electrically conducted as shown in state  4 , state  1  and state  2  respectively. In other words, the tilt sensor  100  is able to deduce the rotation state thereof based on which one of the metal pad pair  128 ,  122  and  124  is conducted. 
     In addition, in the tilt sensor  100  applied in sensing various rotation angles, the shape of the movement region  112  is able to be designed as polygons mentioned above. Thus, the tilt sensor  100  is capable of sensing substantially more rotation angles. For example, when movement region  122  is regular hexagon, the rotation angles able to be sensed are 60, 120, 180 and 270 degree. When the movement region  122  is regular nonagon, the rotation angles able to be sensed are 40, 80, 120, 160, 200, 240, 280 and 320 degree. In other words, for the movement region  120  shaped in n-sided polygon, the greater n is, the more the rotation angles are able to be sensed, and the shape of the movement region  120  is designed according to user&#39;s requirement. The abovementioned is given as an example, but not intended to limit the scope of the invention. 
     In summary, the tilt sensor of the invention has at least the following advantages. First, the structure of the body is appropriately designed. In detail, the movement region therein is designed as having a plurality of corners, and one metal pad pair is disposed at least a portion of the corners. When the moving element in the movement region moves to one of the corners due to gravity, the metal pads of the metal pad pair in the correspond corner are electrically connected with each other via the moving element. In other words, by utilizing the characteristic of the moving element moving to one of the corners to make the metal pad pair therein be electrically conducted, the tilt direction of the tilt sensor is able to be deduced in a simple sensing manner. Moreover, the size of the moving element is larger than 0.1 mm and smaller than or equal to 0.5 mm, such that the thickness of the tilt sensor is effectively reduced. 
     Though the invention has been disclosed above by the embodiments, they are not intended to limit the present invention. Anybody skilled in the art can make some modifications and variations without departing from the spirit and scope of the invention. Therefore, the protecting range of the invention falls in the appended claims.