Patent Publication Number: US-2013249826-A1

Title: Method and apparatus for detecting touch

Description:
PRIORITY 
     This application claims priority under 35 U.S.C. §119(a) to a Korean Patent Application filed in the Korean Intellectual Property Office on Mar. 23, 2012, and assigned Serial No. 10-2012-0029941, the entire disclosure of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method of detecting touch inputs from a user through a touch-screen of a portable terminal, and more particularly, to a method and apparatus for detecting touches, by which touch inputs from a user are smoothly detected no matter what state the touch screen is in. 
     2. Description of the Related Art 
     Today, portable terminals, such as mobile communication terminals, personal digital assistants (PDAs), smart phones, etc. for providing various functions have become more popular. 
     As the portable terminal provides various functions such as wireless Internet, electronic notebook, multimedia capture/play, gaming functions, etc., in addition to a basic communication function, a more diverse input device is demanded. In addition to this demand, touch-screens having input and display units implemented in a single device are widely used in small terminals, such as portable terminals. The touch-screens are classified into any of capacitive overlay, resistive overlay, surface acoustic wave, transmitter, and infrared beam types, etc. Among them, the usage of capacitive overlay type touch-screens has been on the rise with development of a user interface using multi-touches. 
     For the capacitive overlay type touch-screen, if the touch-screen is not electrically grounded, i.e., the touch-screen is floating, an amount of change in capacity is noticeably small compared with a case the touch-screen is electrically grounded. This causes the portable terminal to fail to recognize touch inputs even when touch inputs to the portable terminal are received through the touch-screen from a user. In particular, when calculating size or angle data of a touch input from the touch input, the failure to recognize the touch input causes inconvenience to the user of the portable terminal. For example, if functions are differently implemented depending on areas of touch inputs, an incorrect recognition of the size of a touch input hinders the portable terminal from smoothly implementing a function desired by the user. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is designed to address at least the problems and/or disadvantages described above and to provide at least the advantages described below. 
     The present invention provides a method and apparatus for detecting touches, by which a touch input from a user may be smoothly detected no matter what state a touch-screen is in. 
     In accordance with an aspect of an embodiment of the present invention, there is provided a method of detecting touches on a touch-screen, the method including detecting a touch input from a user through the touch-screen; generating touch data based on a change in capacity of the touch-screen caused by the touch input; calculating first data for the touch input using the touch data and a predetermined first threshold; and calculating second data for the touch input using the touch data and a predetermined second threshold. 
     In accordance with another aspect of an embodiment of the present invention, there is provided an apparatus for detecting touches, the apparatus including a touch sensor for detecting a touch input from a user through a touch-screen and generating touch data based on a change in capacity of the touch-screen caused by the touch input; a data extractor for calculating first data for the touch input using the touch data and a predetermined first threshold, and calculating second data for the touch input using the touch input and a predetermined second threshold; and a touch controller for controlling an operation of a terminal having the touch-screen in response to the touch input using the first and second data. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages of the present invention will become more apparent from the following detailed description, with reference to the attached drawings, in which: 
         FIG. 1  is a block diagram of an apparatus for detecting touches, according to an embodiment of the present invention; 
         FIG. 2  is a flowchart of a method of detecting touches in the apparatus for detecting touches, as shown in  FIG. 1 ; 
         FIG. 3  is a graph representing touch data resulting from touch inputs detected by the apparatus for detecting touches, shown in  FIG. 1 ; and 
         FIGS. 4A and 4B  represent areas of touch inputs detected by the apparatus for detecting touches, shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION 
     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 present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. 
       FIG. 1  is a schematic block diagram of an apparatus  100  for detecting touches, according to an embodiment of the present invention. 
     Referring to  FIG. 1 , the apparatus  100  includes a touch sensor  110 , a data extractor  120 , a touch controller  130 , and a memory  140 . 
     The touch sensor  110  detects a touch input from a user through a touch-screen (not shown). In the embodiment of the present invention, the touch sensor  110  detects a change in capacity caused by the user pressing the surface of the touch-screen with his/her finger or with a touch pen. The touch sensor  110  generates touch data based on the detected change of capacity, i.e., an amount of the change in capacity. The touch sensor  110  outputs the generated touch data to the data extractor  120 . 
     The touch input detected by the touch sensor  110  includes gestures of the user to cover the entire display screen of the touch screen, a sweep over the left or right of the display screen with the edge of his/her hand, rotation of one or more knuckles on the display screen to the left or right, or the like. 
     The data extractor  120  extracts coordinates, an area, an angle, etc. of the touch input detected by the touch sensor  110 . The data extractor  120  calculates the touch input&#39;s coordinates by using a first threshold, and calculates an area and angle of the touch input by using a second threshold. The first and second thresholds are amounts of changes in capacity of the touch-screen caused by the touch input, with the first threshold being larger than the second threshold. 
     To perform an action in response to the touch input, a terminal (not shown) equipped with the apparatus  100  has to catch the action in response to the touch input. The data extractor  120  extracts the coordinates, area, angle, etc., of where the touch input is received from the user on the touch-screen, and delivers them to the touch controller  130 , so that the touch controller  130  may determine an action in response to the touch input. 
     As such, to determine the action of the terminal in response to the touch input, in addition to the touch input&#39;s coordinates, its area, angle, etc. are also required. Unlike the coordinates that may be obtained without much difficulty no matter what state the terminal is in, the area or angle of the touch input may be difficult to obtain depending on the state of the terminal. In particular, if the terminal is a floating terminal, the amount of change in capacity of the touch-screen is less than when the terminal is grounded, and so it is hard to calculate the area or angle to obtain the touch input&#39;s coordinates. Considering this, in the embodiments of the present invention, the first threshold is applied to obtain the touch input&#39;s coordinates and the second threshold is applied to obtain the area or angle of the touch input. In the embodiments of the present invention, by applying different reference values (the first and second thresholds) for obtaining the coordinates and the area or angle of the touch input, the coordinates as well as the area or angle of the touch input may be correctly calculated. 
     To do this, the data extractor  120  includes a coordinate calculator  122  and an area calculator  124 . 
     The coordinate calculator  122  extracts the touch input&#39;s coordinates. The  20  coordinate calculator  122  calculates the touch input&#39;s coordinates using the first threshold. The coordinate calculator  122  calculates the coordinates of a touch input whose touch data generated by the touch sensor  110  is greater than the first threshold, under control of the touch controller  130 . 
     The area calculator  124  extracts the area or angle of the touch input. The area calculator  124  calculates the area or angle of the touch input using the second threshold. The area calculator  124  calculates the area or angle of a touch input whose touch data generated by the touch sensor  110  is greater than the second threshold, under control of the touch controller  130 . 
     The area calculator  124  extracts angle data using a shape of an area whose amount of change in capacity of the touch-screen is greater than the second threshold. For example, the area calculator  124  calculates an angle of when the user covers the entire display screen of the touch-screen, and/or an angle of an edge of the user&#39;s hand sweeping over the left or right of the display screen. 
     The touch controller  130  controls general operations of the apparatus  100 . 
     For example, the touch controller  130  determines an action of the terminal in response to the touch input of the touch-screen, i.e., a function to be implemented in the terminal in response to the touch input. 
     In an embodiment of the present invention, the touch controller  130  determines whether each touch input corresponding to each touch data generated by the touch sensor  110  is valid. The touch controller  130  determines whether the touch input is valid input data by determining whether each touch data is greater than the first threshold or the second threshold. 
     The first and second thresholds may be reference values for determining whether the touch input detected by the touch sensor  110  is valid input data. Valid input data means that the touch input detected by the touch sensor  110  is input data to trigger a particular action of a device equipped with the apparatus  100 , e.g., a mobile communication terminal. 
     The touch controller  130  controls the coordinate calculator  122  to calculate coordinates of only the touch inputs that correspond to touch data greater than the first threshold, among all touch data. The touch controller  130  also controls the coordinate calculator  122  to calculate areas or angles of only the touch inputs that correspond to touch data greater than the second threshold among all touch data. The touch controller  130  determines only the touch inputs that correspond to the touch data greater than the first threshold or the second threshold to be valid touch inputs. In an embodiment of the present invention, the touch controller  130  controls the touch sensor  110  to generate touch data only for touch inputs that cause amounts of change in capacity to be larger than the first threshold or the second threshold. Then, the touch sensor  110  generates touch data only for the valid touch inputs. 
     The memory  140  stores data for controlling general operations of the apparatus  100 . The first and second thresholds may be stored in the memory  140 , and the touch input&#39;s coordinates, area, angle, etc. calculated by the data extractor  120  may also be stored in the memory  140 . Actions of the terminal in response to the touch inputs&#39; coordinates, areas, or angles calculated by the data extractor  120  may also be stored in the memory  140 . Table 1 represents actions of the terminal in response to touch inputs&#39; coordinates, areas, or angles. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 Touch data 
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 Coordinates 
                 Areas 
                 Angles 
                 Terminal Actions 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 (111, 116) 
                 72 
                 a11 
                 Action A 
               
               
                   
                 (222, 232) 
                 382 
                 a24 
                 Action B 
               
               
                   
                 . . . 
                 . . . 
                 . . . 
                 . . . 
               
               
                   
                   
               
            
           
         
       
     
     The touch controller  130  determines actions of the terminal in response to touch inputs by referring to data as in Table 1 stored in the memory  140 . Taking Table 1 as an example, the coordinates of the touch input detected by the touch sensor  110  are ( 111 ,  116 ), the area is  72 , and the angle is all. The touch controller  130  determines the ‘Action A’ to be an action of the terminal by referring to Table 1 stored in the memory  140 . 
       FIG. 2  is a flowchart of a method of detecting touches in the apparatus  100 , as shown in  FIG. 1 . 
     Referring to  FIG. 2 , the touch sensor  110  detects a touch input from a user through the touch-screen, in step S 202 . When a touch input is received from the user, a capacity changes only at a spot on the touch-screen where the touch input is received. The touch sensor  110  generates data for the change in capacity, i.e., touch data. 
     The touch data generated by the touch sensor  110  is sent to the data extractor  120 . The coordinate calculator  122  of the data extractor  120  calculates the touch input&#39;s coordinates by applying the first threshold, in step S 204 . In step S 206 , the area calculator  124  of the data extractor  120  calculates the area or angle of the touch input received in step S 202  by applying the second threshold, in step S 206 . 
     Following step S 204 , i.e., the operation of calculating the touch input&#39;s coordinates, the operation of calculating the area or angle of the touch input is performed in step S 206 . However, in another embodiment, the sequence may be reversed, i.e., step S 206  may come first, and step S 204  may come next. Alternately, steps S 204  and S 206  may be performed simultaneously. 
     In step S 208 , the touch controller  130  determines an action of the terminal in response to the touch input based on the coordinates, area, or angle of the touch input, calculated in steps S 204  and S 206 . 
       FIG. 3  is a graph representing touch data resulting from touch inputs detected by the apparatus  100 , as shown in  FIG. 1 .  FIG. 3  shows touch data resulting from both cases, whereby the touch-screen of the terminal is grounded and floating. The touch inputs corresponding to both touch data are assumed to have the same coordinates and area. 
     Hereinafter, the touch data when the touch screen is grounded will be referred to as a ‘first touch data Δ 1 ’ and the touch data when the touch screen is floated will be referred to as ‘second touch data Δ 2 ’. Also, touch inputs corresponding to the first touch data Δ 1  and the second touch data Δ 2  will be referred to as ‘first touch input’ and ‘second touch input’, respectively. 
     Referring to  FIG. 3 , a maximum value of the first touch data Δ 1  is greater than a maximum value of the second touch data Δ 2 . In other words, the amount of change in capacity of the touch-screen when the touch screen is grounded is greater than when the touch screen is floating. 
     As shown in  FIG. 3 , the coordinates of the first and second touch inputs are the same (X a , Y b ). The coordinate calculator  122  of the data extractor  120  applies the first threshold to calculate the coordinates of the first and second touch inputs. The area calculator  124  of the data extractor  120  applies the second threshold to calculate the areas of the first and second touch inputs. 
     As shown in  FIG. 3 , when the touch-screen is grounded, a value of the first touch data Δ 1  is large even compared with the first threshold. Thus, the data extractor  120  may easily calculate the coordinates and the area of the first touch input. However, when the touch-screen is floating, a value of the second touch data Δ 2  is relatively small compared with the first touch data Δ 1 . It is not easy for the data extractor  120  to calculate the area of the second touch input, as shown in  FIG. 3 , when based on the first threshold. 
     Thus, the apparatus  100  is configured to obtain the coordinates, the area or angle of the touch input, by applying the first threshold to obtain the touch input&#39;s coordinates, and second threshold to obtain the area or angle of the touch input. 
     In  FIG. 3 , diameters of the first and second touch inputs are shown as ‘D 1 ’ and ‘D 2 ’, respectively. As shown in  FIG. 3 , the first and second touch inputs have almost similar diameters. Since the second touch input has a small area that includes touch data greater than the first threshold, the data extractor  120  has difficulty calculating the area of the second touch input based on the first threshold. On the other hand, once the area of the second touch input is calculated based on the second threshold, it is possible for the data extractor  120  to calculate a similar area to that of the first touch input as area information of the second touch input. 
       FIGS. 4A and 4B  represent the first and second touch inputs shown in  FIG. 3 .  FIG. 4A  shows a case where the first threshold is applied to obtain the coordinates of each of the first and second touch inputs, and  FIG. 4B  shows a case where the second threshold is applied to obtain an area of each of the first and second touch inputs. In  FIGS. 4A and 4B , dashed circles A are assumed to be actual areas of touch inputs from the user. 
     Referring to  FIG. 4A , in the case of applying the first threshold, the first touch input corresponding to the first touch data Δ 1  is detected to have an almost similar area to the actual area A of the first touch input. On the other hand, the second touch input corresponding to the second touch data Δ 2  is detected to have much smaller area than that of the actual area A of the second touch input. Since the first threshold is a reference value for obtaining the coordinates of the first and second touch inputs, the data extractor  120  calculates the coordinates (X a , X b ) inside the first and second touch inputs only with the areas of the first and second touch inputs. 
     Referring to  FIG. 4B , not only the area of the first touch input corresponding to the first touch data Δ 1 , but also the area of the second touch input corresponding to the second touch data Δ 2 , is detected to be almost similar to its actual area A. Therefore, the apparatus  100  may efficiently detect the first and second touch inputs by calculating areas of the first and second touch inputs based on the second threshold. 
     While the present invention has been particularly shown and described with reference to certain embodiments thereof, 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 of the present invention as defined by the following claims.