Abstract:
An input apparatus and method for tactile sensing are disclosed. The input apparatus includes a sensor array for outputting input data in an array format according to a touch input, and a controller for obtaining first input data for a first input from the sensor array if the first input above a predetermined pressure is imposed on the sensor array, for obtaining second input data for a second input from the sensor array if the second input above a predetermined pressure is imposed on the sensor array, for generating third input data indicating an input characteristic by comparing the first input data and the second input data, and for operating according to a program based on the third input data.

Description:
CLAIM OF PRIORITY 
       [0001]    This application claims the benefit of the earlier filing date, under 35 U.S.C. §119(a), to that patent application filed in the Korean Intellectual Property Office on Jul. 27, 2007 and assigned Serial No. 2007-75525, the entire disclosure of which is herein incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to tactile devices and more particularly, to a pressure sensor array apparatus having multiple input levels usable in a compact device. 
         [0004]    2. Description of the Related Art 
         [0005]    In currently used mobile terminals, a keypad is used as a primary input device. Typically, the keypad is constructed of mechanical switches in a two-dimensional array format. The keypad has a significantly low spatial resolution. Only two-dimensional locations can be used as an input value in the keypad. 
         [0006]    The use of mechanical switches allows only an On/Off input on a predetermined area, and a user may feel very uncomfortable to press the switch by using his or her finger. The conventional keypad is limited in use since it receives an input of a predetermined key area. Moreover, the conventional keypad cannot be used for other purposes. 
         [0007]    The conventional keypad can receive an input only according to a predetermined key. Thus, it is impossible to reconfigure the key for other purposes. In addition, the key has a limited size. 
         [0008]    Four directional keys (i.e., left, right, top, and down) may be used so that flexible movement can be received by the user as an input by using the conventional keypad. However, the directional keys are still insufficient to provide a flexible movement. 
         [0009]    A touchpad to be described below is another example of an input device. In order to sense movement on the touchpad, an input location needs to be moved by a user. That is, the user has to move a specific input location to extract a motion vector, which results in a spatial movement. 
         [0010]    Since the conventional touchpad delivers the input in an On/Off manner, a pressure (e.g., a degree of strength, a level, a tactile sense, etc.) imposed by the user cannot be distinguished different levels. 
         [0011]    If the touchpad is used without consideration of the pressure as described above, an input that may be significantly sensitive or insensitive in operation since sensibility of the touchpad cannot be controlled. In addition, an abnormal operation may be caused when the user mistakenly presses an adjacent key. 
         [0012]    A touch screen to be described below is another example of the input device. The touch screen can be implemented in various manners and is primarily used to recognize a touched location of the screen. It is difficult for the touch screen to be used for other purposes. 
         [0013]    The conventional touch screen is assumed to be a screen (i.e., a panel). The touch screen is designed for the purpose of touching the screen and, optionally, can perform a multi-touch function, a drag function, etc. 
         [0014]    However, the touch screen has the same disadvantages as the touchpad with regard to being sensitive to different levels of pressure. Further, the touch screen has a limit in durability, and thus it is difficult to be used as a mouse or an input device for identifying multiple pressures. 
         [0015]    Therefore, the aforementioned exemplary input devices cannot distinguish the pressures imposed by a user and is insensitive to the application of different pressure levels. 
       SUMMARY OF THE INVENTION 
       [0016]    Accordingly, an aspect of the present invention is to provide a pressure sensor array apparatus and method for tactile sensing. 
         [0017]    Another aspect of the present invention is to provide an input apparatus and method capable of changing data by analyzing a tactile input array 
         [0018]    Another aspect of the present invention is to provide an input apparatus and method in which motion sensing, continuous operations of movement and touch, and pressure information can be obtained in a small area in a mobile terminal and a compact game terminal. 
         [0019]    Another aspect of the present invention is to provide an apparatus, having a high resolution and a compact size, for receiving and analyzing an input in an 1 area, and a method thereof. 
         [0020]    Another aspect of the present invention is to provide an apparatus and method capable of integrating multiple functions such as a mouse, a keypad, a key input, a joystick, etc., into one input device. 
         [0021]    Another aspect of the present invention is to provide an apparatus and method capable of responding to continuous operational inputs and pressures by using for example, a distribution of input pressures, an area of a pressure, a center of gravity, an acceleration, movement of a center point, three-dimensional calculation, etc. 
         [0022]    Another aspect of the present invention is to provide an apparatus and method capable of representing human sensitivity according to a human touch by analyzing a degree of strength, repetition, strength, pressure variation, touch time, etc. 
         [0023]    In accordance with an aspect of the present invention, an input apparatus for tactile sensing is provided. The apparatus includes a sensor array for outputting input data in an array format according to a touch input, and a controller for obtaining first input data for a first input from the sensor array if the first input above a predetermined pressure is imposed on the sensor array, for obtaining second input data for a second input from the sensor array if the second input above a predetermined pressure is imposed on the sensor array, for generating third input data indicating an input characteristic by comparing the first input data and the second input data, and for operating according to a program based on the third input data. 
         [0024]    In accordance with another aspect of the present invention, an input method for tactile sensing is provided. The method includes obtaining first input data for a first input if the first input above a predetermined pressure is imposed on a sensor array that outputs input data in an array format, obtaining second input data for a second input if the second input above a predetermined pressure is imposed on the sensor array, generating third input data indicating an input characteristic by comparing the first input data and the second input data, and operating according to a program based on the third input data. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    The above and other aspects, features and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which: 
           [0026]      FIG. 1  is a block diagram of an input device according to an exemplary embodiment of the present invention; 
           [0027]      FIG. 2  illustrates an input process using a sensor array according to an exemplary embodiment of the present invention; 
           [0028]      FIG. 3  illustrates an internal structure of a sensor array according to an exemplary embodiment of the present invention; 
           [0029]      FIG. 4  illustrates a driving circuit for driving a sensor array and its peripheral elements according to an exemplary embodiment of the present invention; 
           [0030]      FIG. 5A  is a flowchart illustrating an input process according to a first exemplary embodiment of the present invention; 
           [0031]      FIG. 5B  illustrates an example of an input applied to a keypad according to an exemplary embodiment of the present invention; 
           [0032]      FIG. 6A  is a flowchart illustrating an input process according to a second exemplary embodiment of the present invention; 
           [0033]      FIG. 6B  illustrates an example of an input applied to a touchpad, a mouse, and a joystick according to an exemplary embodiment of the present invention; 
           [0034]      FIG. 7  illustrates an input applied to a side key according to an exemplary embodiment of the present invention; 
           [0035]      FIG. 8A  illustrates an input applied to a navigation key according to an exemplary embodiment of the present invention; 
           [0036]      FIG. 8B  illustrates an input applied to a game according to an exemplary embodiment of the present invention; 
           [0037]      FIG. 9A  illustrates an input applied to a musical instrument according to an exemplary embodiment of the present invention; and 
           [0038]      FIG. 9B  illustrates an input used as a mouse function for map search according to an exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0039]    Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. 
         [0040]    A pressure sensor array apparatus and method for tactile sensing is described. 
         [0041]    The present invention uses a plurality of tactile input arrays capable of measuring location information indicating a point where a user presses and a degree of strength exerted when the user presses the point. 
         [0042]    The tactile input array can continuously receive information on a plurality of locations and pressures through the array during a time period when the user presses the array. Since the tactile input array must sense delicate movement of a finger, it must be designed to be below a minimum resolution of the finger, which in one aspect of the invention is below 1 millimeter (mm). 
         [0043]    In the tactile input array, user&#39;s intention is recognized by using an analysis result of a location, pressure, and movement of an input. Various applications are possible according to an analysis method. 
         [0044]    That is, with a user interface using the tactile input array, functions of a keypad, a multi-key pad, a mouse, a joystick, etc., can be implemented by combining information on a plurality of tactile inputs (i.e., location information) and pressures which are input by the user. 
         [0045]    Signals are input through the tactile input array, and are analyzed by using an analysis method according to respective purposes in order to recognize user&#39;s intention. The analysis method includes finding a center-of-gravity point, moving a center point, detecting a pressure threshold, calculating a pressure distribution, analyzing an input profile, etc. 
         [0046]      FIG. 1  is a block diagram of an input device according to an exemplary embodiment of the present invention. 
         [0047]    Referring to  FIG. 1 , the input device consists of a first interface  110 , a storage unit  120  including a software part  121  and a memory part  123 , a controller  125 , a second interface  130 , a driving circuit  135 , and a sensor array  140 . 
         [0048]    The sensor array  140  is a pressure sensor array. Location data and pressure data are input to the sensor array  140  by using a finger or a stylus. 
         [0049]    The driving circuit  135  analyzes an output value of the sensor array  140  and thus detects the location and pressure input to the sensor array  140 . 
         [0050]    The second interface  130  connects the driving circuit  135  and the controller  125 . 
         [0051]    The controller  125  analyzes the location and pressure output from the driving circuit  135  and thus performs operations according to the software part  121  and algorithms (or data) stored in the memory part  123 . Functions of the controller  125  will be described below in detail. 
         [0052]    The first interface  110  is used to transmit a processing result of the memory part  123  and includes both wired and wireless interfaces. 
         [0053]      FIG. 2  illustrates an input process using a sensor array according to an exemplary embodiment of the present invention. 
         [0054]    Referring to  FIG. 2 , a sensor array  210  of the present invention is an input device having a resolution of 1 mm and using a minimum resolution of a finger  230 . 
         [0055]    The sensor array  210  can sense a pressure imposed by the finger  230  at an intersection point  220  and has a sufficient capacity so that general strength imposed by a user can be distinguished in several levels. In general, the sensor  210  can sense the pressure in the range of 100 g to 10 kg. 
         [0056]      FIG. 3  illustrates an internal structure of a sensor array according to an exemplary embodiment of the present invention. 
         [0057]    Referring to  FIG. 3 , the sensor array can be implemented using various elements. A capacitor is used in  FIG. 3  to implement the sensor array. 
         [0058]    In addition to the capacitor, a resistor may be used to implement the sensor array. A surface acoustic wave may be used in implementation. 
         [0059]    The sensor array can sense a pressure imposed by a finger, for example, and has a sufficient capacity so that general strength imposed by a user can be distinguished in several levels. In general, the sensor array can sense the pressure in the range of 100 g to 10 kg. 
         [0060]      FIG. 4  illustrates a driving circuit for driving a sensor array and its peripheral elements according to an exemplary embodiment of the present invention. 
         [0061]    The driving circuit of  FIG. 4  is the same as the driving circuit  135  of  FIG. 1 . A function of a digital signal processor  480  may be performed by the controller  125  of  FIG. 1 . 
         [0062]    It is assumed that a sensor array  430  uses a capacitor as an internal element. 
         [0063]    The driving circuit consists of a row analyzer  410 , a Demultiplexer (or Demux)  420 , a Multiplexer (or Mux)  425 , a column analyzer  415 , a resolution controller  440 , a filter  450 , an amplifier  460 , and an Analog Digital Converter (ADC)  470 . 
         [0064]    The row analyzer  410  determines a signaling order with respect to all row input elements existing on the sensor array  430 . 
         [0065]    The Demux  420  provides the sensor array  430  with specific level of voltage according to the order determined by the row analyzer  410 . 
         [0066]    The column analyzer  415  determines an order for extracting column data to be output to the sensor array  430 . 
         [0067]    The Mux  425  extracts data according to the order determined by the column analyzer  415  and outputs the extracted data to the filter  450 . 
         [0068]    The filter  450  removes a noise component from a received signal and then outputs the noise-removed signal to the amplifier  460 . 
         [0069]    The amplifier  460  amplifies the noise-removed signal and then outputs the amplified signal to the ADC  470 . 
         [0070]    The ADC  470  converts the amplified signal into a digital signal and then outputs the converted signal to the digital signal processor  480 . 
         [0071]    The digital signal processor  480  processes the converted digital signal and determines an input direction, a pressure, a location, etc. Operations of the digital signal processor  480  are described below. 
         [0072]    The resolution controller  440  adjusts an input resolution of the sensor array  430 . In general, it is known that a human finger has a resolution in the range of 0.7 to 1 mm. When used in an area above 10 mm, a large number of contact points are produced, and thus more operations are needed to process the contact points. Therefore, an application program is used to reduce the resolution by one-quarter (¼) in width and one-half (½) in length. In general, the width and the length are divided according to odd and even arrangements to determine On/Off. 
         [0073]      FIG. 5A  is a flowchart illustrating an input process according to a first exemplary embodiment of the present invention. 
         [0074]    Referring to  FIG. 5A , a resolution of a sensor array is determined (step  550 ). 
         [0075]    If a sensing point on the sensor array is driven according to an input of a user (step  555 ), i.e., if the user presses the sensor array, it is determined whether a pressure imposed by the user is above a specific level, i.e., a pressure threshold (step  560 ). A minimum input value for operation may change according to a standard such as an application program driving scenario. 
         [0076]    If the pressure is above the pressure threshold, the input is analyzed according to a coordinate and a pressure difference of the input (step  565 ). The pressure values are 3-dimensionally added up. 
         [0077]    For example, a row coordinate (i.e., Xs coordinate) may be obtained by Xs=Σz*X/Σz, and a column coordinate (i.e., Ys coordinate) may be obtained by Ys=Σz*Y/Σz. In addition, a pressure sum Σz may be classified according to a level N to obtain pressure strength (i.e., level N≧Σz≧level N−1). 
         [0078]    To minimize an input error, a method such as “Moving Average” may be used in which locations are measured several times and the measured locations are divided by the number of measurements. 
         [0079]    In addition, an input depending on the pressure difference can be distinguished. In this case, a user&#39;s intention can be recognized according to a total sum of pressures or a variation of a pressed area (or combination of the two). 
         [0080]    Since the pressure strength can be distinguished at the same location according to the method of the present invention, another input can be received without having to move the finger. 
         [0081]    Thereafter, a predetermined function is performed according to the input analysis result (step  570 ), and the procedure of  FIG. 5A  ends. 
         [0082]      FIG. 5B  illustrates an example of an input applied to a keypad according to an exemplary embodiment of the present invention. 
         [0083]    Referring to  FIG. 5B , the keypad consists of a sensor array. In this example, separate characters are input according to pressure strength of the input applied to a specific area. 
         [0084]    That is, one of Korean consonants (i.e.,          ,          , and          ) can be selectively input according to the pressure strength based on the input. 
         [0085]      FIG. 6A  is a flowchart illustrating an input process according to a second exemplary embodiment of the present invention. 
         [0086]    Referring to  FIG. 6A , a resolution of a sensor array is determined (step  650 ). 
         [0087]    If a sensing point on the sensor array is driven according to an input of a user (step  655 ), i.e., if the user presses the sensor array, it is determined whether a pressure imposed by the user is above a specific level (pressure threshold), i.e., a pressure threshold (step  660 ). A minimum input value for operation may change according to a standard such as an application program driving scenario. 
         [0088]    If the pressure is above the pressure threshold, the input is analyzed according to a coordinate and a pressure difference with respect to the pressure threshold of the input (step  665 ). The pressure values are 3-dimensionally added up. 
         [0089]    For example, a row coordinate (i.e., Xs coordinate) may be obtained by Xs=Σz*X/Σz, and a column coordinate (i.e., Ys coordinate) may be obtained by Ys=Σz*Y/Σz. 
         [0090]    Thereafter, current data is compared with previous data, a pressure is three-dimensionally analyzed, and an input based on a pressure difference between the current pressure and the previous pressure is analyzed (step  670 ). The previous data can be the first input data and the current data can be the second input data, when an input order is considered. 
         [0091]    The data may represent be an area, a speed, an acceleration, a location, a direction, etc. Various algorithms can be used to predict a movement direction of a user input by moving only a finger tip. 
         [0092]    For example, an angle of movement can he obtained in such a manner that variations of X and Y (i.e., dX=Xs(N)−Xs(N−1), dY=Ys(N)−Ys(N−1)) are predicted to calculate an “arc tangent” between two coordinates, that is, Vector(θ)=Arctan(dY/dX). This is represented with an angle indicating a user movement. 
         [0093]    In addition, movement can be obtained by simply calculating a movement point of a center of gravity. In this case, it is important to calculate a pressure. Further, distinctions of a pressure difference (i.e., dZ=ZYs(N)−Zs(N−1)), a pressure sum (i.e., Σz), a pressure level (i.e., level N≧Σz≧level N−1) must also be taken into consideration. 
         [0094]    In general, since an area in contact with the finger increases when it is pressed with more strength, a sum (i.e., ΣX*(Z&gt;minimum pressure)+ΣY*(Z&gt;minimum pressure)) of areas whose pressure values are changed also needs to be taken into consideration. 
         [0095]    As described above, a pressure distribution is sequentially obtained according to movement of the finger. By using the distribution together with several algorithms, user&#39;s intention can be recognized with a small movement Accordingly, a key input can be achieved while the input device is used as a mouse, a joystick, or a touchpad. 
         [0096]    Thereafter, a predetermined function is performed according to the input analysis result (step  675 ), and the procedure of  FIG. 6A  ends. 
         [0097]      FIG. 6B  illustrates an example of an input applied to a touchpad, a mouse, and a joystick according to an exemplary embodiment of the present invention. 
         [0098]    Referring to  FIG. 6B , an input unit consists of a sensor array. The input unit senses and analyzes a location, movement, and pressure of a user input, and operates according to an algorithm designed on the basis of the analysis result. 
         [0099]      FIG. 7  illustrates an input applied to a side key according to an exemplary embodiment of the present invention. 
         [0100]    Referring to  FIG. 7 , the side key consists of a sensor array. Volume change depending on a pressure is shown in the figure. For example, the volume may increase in proportion to the pressure. 
         [0101]      FIG. 8A  illustrates an input applied to a navigation key according to an exemplary embodiment of the present invention. 
         [0102]    Referring to  FIG. 8A , a mobile terminal is equipped with the navigation key. If the navigation key is constructed of a sensor array, a current location can be recognized by calculating a cursor point when the input is applied. A direction of movement can be known by obtaining a vector direction. 
         [0103]      FIG. 8B  illustrates an input applied to a game according to an exemplary embodiment of the present invention. 
         [0104]    Referring to  FIG. 8B , a missile and a bomb call be distinguished using pressure strength in a shooting game. In addition, movement of a user character can be controlled. That is, different operations can be performed according to the pressure strength. 
         [0105]      FIG. 9A  illustrates an input applied to a musical player according to an exemplary embodiment of the present invention. 
         [0106]    Referring to  FIG. 9A , an input area is defined in a sensor array so that a different musical instrument can be played according to the area. A degree of strength can be distinguished according to a pressure applied. Human sensitivity can be delivered by distinguishing strength/weakness of touch, time, location, repetition, etc. 
         [0107]    That is, a base sound, a hi-hat sound, and a tom-tom sound can be selectively played according to the area upon which a pressure is applied. 
         [0108]      FIG. 9B  illustrates an input used as a mouse function for map search according to an exemplary embodiment of the present invention. 
         [0109]    Referring to  FIG. 9B , by using the aforementioned mouse function, a zoom-in function can be performed by adding a pressure at a desired position while searching a map. A zoom-out function can be performed by reducing the pressure. 
         [0110]    A mouse function can be resumed and performed by adding a pressure at a desired position, after a finger is removed from the desired position This method adds convenience when using a compact device. 
         [0111]    Since the pressure can be sensed according to a user&#39;s touch, the present invention has an advantage in that a different output can be obtained according to pressure strength. 
         [0112]    According to the present invention, motion sensing, continuous operations of movement and touch, and pressure information can be obtained in a small area in addition to a limited input that can be obtained through a conventional keypad, touchpad, mouse, etc., in a mobile terminal and a compact game terminal. Therefore, it is possible to implement a more evolved input device\such as a touchpad, a keypad, a mouse, a joystick, etc. 
         [0113]    The above-described methods according to the present invention can be realized in hardware or as software or computer code that can be stored in a recording medium such as a CD ROM, an RAM, a floppy disk, a hard disk, or a magneto-optical disk or downloaded over a network, so that the methods described herein can be rendered in such software using a general purpose computer, or a special processor or in programmable or dedicated hardware, such as an ASIC or FPGA. As would be understood in the art, the computer, the processor or the programmable hardware include memory components, e.g., RAM, ROM, Flash, etc. that may store or receive software or computer code that when accessed and executed by the computer, processor or hardware implement the processing methods described herein. 
         [0114]    While the present invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims and their equivalents. Therefore, the scope of the invention is defined not by the description of the invention but by the appended claims and their equivalents, and all differences within the scope will be construed as being included in the present invention.