Abstract:
A method for detecting a touch status of a surface of an input device, comprising: utilizing a first two-dimension (2D) image sensor disposed at a first location for capturing a first captured image of an object on the surface; and outputting a plurality of first positions of the object relative to the surface respectively by analyzing horizontal lines of the first captured image.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to touch status detection, and more particularly, to a method for detecting a touch status of a surface of an input device and the input device employing the method. 
         [0003]    2. Description of the Prior Art 
         [0004]    Touch panels are widely used in various consumer electronic products, which allow users to use fingers or touch pens to select desired images or characters from the screen and input information and perform operations by touching the touch panel screen. 
         [0005]    Traditional touch panels are divided into various types according to different sensing methods. By way of example, a touch panel may be a resistive type touch panel or a capacitive type touch panel. Resistive type touch panels are composed of two indium tin oxide (ITO) conductive films stacked on top of one another, wherein by applying pressure to electrically connect the two conductive films, a controller is used to measure the voltage difference of the panel and calculate the coordinates of a touch input. Capacitive type touch panels are composed of transparent glass substrates and an oxide metal coated on a surface of the glass substrate. The sensing structures of the capacitive type touch panels are composed of two electrode layers electrically connected along an x-axis direction and a y-axis direction, respectively, and an insulating layer is disposed between the two electrode layers such that the capacitive difference generated by an electrostatic reaction from the fingers of a user and an electrical field is used to determine a touch input. 
         [0006]    In recent years, an optical sensor used in a touch panel has been devised. It is more suitable and economical to use in a large area touch panel. When manufacturing large area touch panels, there is a proportional increase in the cost of “sensing” material (e.g., ITO conductive films) of the resistive type or capacitive type touch panels. Because there is no “sensing” material in an optical touch panel, increasing the size of the touch panel does not result in a proportional increase of the manufacturing cost of the optical touch panel. Some conventional optical touch panels use one dimension (1D) barcode readers or special designed linear optical sensors as a touch detecting sensor. However, the above-mentioned optical touch panels cannot sense the touch pressure or stroke intensity of drawing. Furthermore, the linear optical sensor is long and thin which is hard to slice and lay out, thereby requiring higher manufacturing cost. 
       SUMMARY OF THE INVENTION 
       [0007]    It is therefore one of the objectives of the present invention to provide a method for detecting a touch status of a surface of an input device and the input device employing the method, to solve the above mentioned problem. 
         [0008]    According to a first embodiment of the present invention, an exemplary method for detecting a touch status of a surface of an input device, the method comprises: utilizing a first two-dimension (2D) image sensor disposed at a first location for capturing a first captured image of an object on the surface; and outputting a plurality of first positions of the object relative to the surface respectively by analyzing horizontal lines of the first captured image. 
         [0009]    According to a second embodiment of the present invention, an exemplary method for detecting a touch status of a surface of an input device, comprising: utilizing a 2D image sensor disposed at a first location for capturing a first captured image of an object on the surface, wherein the object have a first part and a second part, wherein the second part has different optical characteristic from that of the first part; and outputting a touch pressure by a vertical position of the first part in the first captured image. 
         [0010]    According to a third embodiment of the present invention, an input device is disclosed. The input device comprises a first 2D image sensor and a touch controller. The 2D image sensor is disposed at a first location of a surface, for capturing a first captured image of an object on the surface. The touch controller is for outputting a plurality of first positions of the object relative to the surface respectively by analyzing horizontal lines of the first captured image. 
         [0011]    According to a fourth embodiment of the present invention, an input device is disclosed. The input device comprises an object, a 2D image sensor and a touch controller. The object has a first part and a second part, wherein the second part has different optical characteristic from that of the first part. The first 2D image sensor disposed at a first location of a surface, for capturing a first captured image of the object on the surface. The touch controller is for outputting a touch pressure by analyzing a vertical position of the first part in the first captured image. 
         [0012]    These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a diagram illustrating an input device according to an exemplary embodiment of the present invention. 
           [0014]      FIG. 2  is a diagram illustrating an input device according to another exemplary embodiment of the present invention. 
           [0015]      FIG. 3  is a diagram illustrating an input device according to yet another exemplary embodiment of the present invention. 
           [0016]      FIG. 4  is a flowchart illustrating a method for detecting a touch status of a surface of an input device according to an exemplary embodiment of the present invention. 
           [0017]      FIG. 5  is a flowchart illustrating a method for detecting a touch status of a surface of an input device according to another exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, electronic equipment manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms “include” and “comprise” are used in an open-ended fashion, and thus should be interpreted to mean “include, but not limited to . . . ”. Also, the term “couple” is intended to mean either an indirect or direct electrical connection. Accordingly, if one device is coupled to another device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections. 
         [0019]    Please refer to  FIG. 1 .  FIG. 1  is a diagram illustrating an input device  100  according to an exemplary embodiment of the present invention. The input device  100  includes, but is not limited to, a two-dimension (2D) image sensor  110 , a cylindrical concave lens  120 , and a touch controller  130 , wherein a plate reflector (not shown in  FIG. 1 ), e.g., a mirror, is placed correspondingly in a opposing direction to the 2D image sensor  110 . The input device  100  is used on a plate  140 , such as a monitor or other plane. The 2D image sensor  110  is used for capturing a first scene at one side of a surface of the plate  140  to obtain a first captured image. The cylindrical concave lens  120  is placed in front of the 2D image sensor  110 , and implemented for spreading a size of an image of the first scene to be formed on the 2D image sensor  110 . The touch controller  130  is coupled to the 2D image sensor  110 , and implemented for analyzing at least a portion of the first captured image to detect the touch status of the surface of the plate  140 . Please note that, in this embodiment, the input device  100  is an optical touch apparatus, the cylindrical concave lens  120  is an optical device which spreads the size of the image of the first scene to be formed on the 2D image sensor  110 ; however, this is for illustrative purposes only, and is by no means a limitation to the scope of the present invention. Using another optical device that supports the spreading capability also falls within the scope of the present invention. Moreover, the cylindrical concave lens  120  is preferably implemented to increase the image size of the first scene formed on the 2D image sensor  110 ; however, it may be omitted in alternative embodiments of the present invention, depending upon design considerations. 
         [0020]    In one exemplary embodiment, the 2D image sensor  110  includes a plurality of sensor rows  112 _ 1 - 112 _m. The touch controller  130  includes a readout circuit  132  and an analyzing circuit  134 . The readout circuit  132  is used for reading the sensor rows  112 _ 1 - 112 _m of the 2D image sensor  110  one by one, thereby generating a plurality of readout data Rout 1 -Routm. The analyzing circuit  134  is used for analyzing the readout data Rout 1 -Routm read by the readout circuit  132  to detect the touch status of the surface of the plate  140 . As shown in  FIG. 1 , a touch pen  150  is shown positioned in the sensing area of the 2D image sensor  110 . The cylindrical concave lens  120  spreads a size of the touch pen  150  to form on the 2D image sensor  110 . The touch controller  130  reads the sensor rows of the 2D image sensor  110  one by one to generate the readout data Rout 1 -Routm. Then, the touch controller  130  analyzes the readout data Rout 1 -Routm to detect the touch position of the touch pen  150 . In this exemplary embodiment, the frame rate of the 2D image sensor  110  is 30 fps (frame per second) where m is equal to 50. Therefore, the refresh rate of the input device  100  can be regarded as 1500 fps. 
         [0021]    In another exemplary embodiment, the readout circuit  132  divides the sensor rows  112 _ 1 - 112 _m into n sensor groups G 1 -Gn. In one exemplary embodiment, m is equal to 50 and n is equal to 10. That is, the first sensor group G 1  includes the sensor rows  112 _ 1 ,  112 _ 11 ,  112 _ 21 ,  112 _ 31 ,  112 _ 41 ; the second sensor group G 2  includes the sensor rows  112 _ 2 ,  112 _ 12 ,  112 _ 22 ,  112 _ 32 ,  112 _ 42 , and so on (please note that only two sensor groups G 1  and G 2  are illustrated for simplicity and clarity). However, this is for illustrative purposes only, and is by no means a limitation to the scope of the present invention. That is, m and n can be other positive integers. The readout circuit  132  reads the sensor groups G 1 -G 10  one by one, thereby generating a plurality of readout data Rout 1 ′-Rout 10 ′. The analyzing circuit  134  analyzes the readout data Rout 1 ′-Rout 10 ′ read by the readout circuit  132  to detect the touch pressure of the surface of the plate  140 . 
         [0022]    As shown in  FIG. 2 , two extensible touch pens  250 ,  260  are positioned in the sensing area of the 2D image sensor  110 . The extensible touch pen  250  includes an elastic element  252 , a first part  254  and a second part  256 . The second part  256  is used for having a contact with the surface of the plate  140 , wherein the second part  256  is movably connected to the first part  254  via the elastic element  252 , and an optical characteristic of the first part  254  is different from an optical characteristic of the second part  256 . In this exemplary embodiment, the elastic element  252  is a spring, the first part  254  is made of an opaque material and the second part  256  is made of a transparent material. The extensible touch pen  260  includes an elastic element  262 , a first part  264  and a second part  266 . The structure and material of the extensible touch pen  260  is the same as the extensible touch pen  250 , so further details are omitted here for brevity. 
         [0023]    The cylindrical concave lens  120  spreads the sizes of the images of the extensible touch pens  250 ,  260  to form on the 2D image sensor  110 . The touch controller  130  reads the sensor groups G 1 -G 10  one by one to respectively generate the readout data Rout 1 ′-Rout 10 ′. Then, the touch controller  130  detects the touch pressure of the extensible touch pens  250 ,  260  by analyzing the light rejection area (e.g., a dark area) and light acceptance area (e.g., a bright area) formed on the 2D image sensor  110  according to the readout data Rout 1 ′-Rout 10 ′. As shown in  FIG. 2 , the touch pressure of the extensible touch pen  260  is larger than the touch pressure of the extensible touch pen  250 , therefore, the dark area formed on the 2D image sensor  110  of the extensible touch pen  260  is much longer than the dark area formed on the 2D image sensor  110  of the extensible touch pen  250 , and the dark area form on the 2D image sensor  110  can be sensed by the sensor groups G 1 -G 10  of the 2D image sensor  110 . In this exemplary embodiment, the frame rate of the 2D image sensor  110  is also 30 fps and n is equal to 10. Therefore, the refresh rate of the input device  100  can be regarded as 300 fps. 
         [0024]    Please note that, in the above-mentioned exemplary embodiment, the extensible touch pens  250 ,  260  are composed of three different components, but this is for illustrative purposes only, and is by no means a limitation to the scope of the present invention. For example, the extensible touch pen can be composed by a first part and a second part. The second part is made of a flexible material and connected to the first part, for having contact with the surface of the plate  140 , and an optical characteristic of the first part is different from an optical characteristic of the second part. The same objective of detecting the touch pressure of the extensible touch pen by analyzing the light rejection area (e.g., a dark area) and light acceptance area (e.g., a bright area) formed on the 2D image sensor  110  is achieved. 
         [0025]    Please refer to  FIG. 3 .  FIG. 3  is a diagram illustrating an input device  300  according to yet another exemplary embodiment of the present invention. The input device  300  includes, but is not limited to, a first 2D image sensor  310 , a second 2D image sensor  320 , a first cylindrical concave lens  330 , a second cylindrical concave lens  340 , a touch controller  350  and a plate  360 , wherein two plate reflector (not shown in  FIG. 3 ), e.g., two mirrors, are placed correspondingly in opposing directions to the first and second 2D image sensor  310  and  320 , respectively. The first 2D image sensor  310  is used for capturing a first scene at a side of a surface of the plate  360  to obtain a first captured image. The first cylindrical concave lens  330  is placed in front of the first 2D image sensor  310 , for spreading a size of an image of the first scene to be formed on the first 2D image sensor  310 . The second 2D image sensor  320  is used for capturing a second scene at the same side of the surface of the plate  360  where the first 2D image sensor  310  is placed to obtain a second captured image. The second cylindrical concave lens  340  is placed in front of the second 2D image sensor  320 , for spreading a size of an image of the second scene to be formed on the second 2D image sensor  320 . The touch controller  350  is coupled to the first 2D image sensor  310  and the second 2D image sensor  320 , and implemented for analyzing at least a portion of the first captured image and a portion of the second captured image to detect the touch status of the surface of the plate  360 . Please note that, in this embodiment, the input device  300  is an optical touch apparatus, and the first cylindrical concave lens  330  and the second cylindrical concave lens  340  are optical devices which spread the size of the images of the first and the second scene to be formed on the first and the second 2D image sensor, respectively; however, this is for illustrative purposes only, and is by no means a limitation to the scope of the present invention. Using another optical device that supports the spreading capability also falls within the scope of the present invention. In addition, provided that the same result can be substantially obtained without one or both of the first cylindrical concave lens  330  and the second cylindrical concave lens  340 , such an alternative design of omitting the cylindrical concave lens still falls within the scope of the present invention. As those skilled in this art can easily understand the operations of the input device  300  after reading the disclosure of the above-mentioned embodiments, further details are omitted here for brevity. 
         [0026]    The abovementioned embodiments are presented merely to illustrate practicable designs of the present invention, and in no way should be considered to be limitations of the scope of the present invention. Those skilled in the art should appreciate that various modifications of the input device may be made without departing from the spirit of the present invention. 
         [0027]      FIG. 4  is a flowchart illustrating a method for detecting a touch status of a surface of an input device according to an exemplary embodiment of the present invention. Please note that the following steps are not limited to be performed according to the exact sequence shown in  FIG. 4  if a roughly identical result can be obtained. The exemplary method includes, but is not limited to, the following steps: 
         [0028]    Step  402 : Utilize a 2D image sensor for capturing a scene at a side of the surface of the input device to obtain a captured image, where the 2D image sensor has a plurality of sensor rows. 
         [0029]    Step  404 : Utilize an extensible device to have a contact with the surface of the input device, wherein the extensible device is within the scene. 
         [0030]    Step  406 : Spread a size of an image of the scene to be formed on the 2D image sensor. 
         [0031]    Step  408 : Analyze at least a portion of the captured image to detect the touch pressure of the surface of the input device. 
         [0032]    In step  408 , the sensor rows are divided into a plurality of sensor groups and are read group by group to generate a plurality of readout data. Then, the readout data are analyzed to detect the touch status of the surface of the input device. As a person skilled in the art can readily understand the related operations of the steps shown in  FIG. 4  after reading the above-mentioned description directed to the input device  100  shown in  FIG. 2 , further description is omitted here for brevity. 
         [0033]      FIG. 5  is a flowchart illustrating a method for detecting a touch status of a surface of an input device according to another exemplary embodiment of the present invention. Please note that the following steps are not limited to be performed according to the exact sequence shown in  FIG. 5  if a roughly identical result can be obtained. The exemplary method includes, but is not limited to, the following steps: 
         [0034]    Step  502 : Utilize a first 2D image sensor for capturing a scene at a side of the surface of the input device to obtain a first captured image, where the first 2D image sensor has a plurality of sensor rows. 
         [0035]    Step  504 : Utilize a second 2D image sensor for capturing a scene at the side of the surface of the input device to obtain a second captured image, where the second 2D image sensor has a plurality of sensor rows. 
         [0036]    Step  506 : Spread a size of an image of the scene to be formed on the first and the second 2D image sensor. 
         [0037]    Step  508 : Analyze at least a portion of the first captured image and a portion of the second captured image to detect the touch position of the surface of the input device. 
         [0038]    In step  508 , the sensor rows of the first 2D image sensor and the sensor rows of the second 2D image sensor are read one by one to generate a plurality of readout data. Then, the readout data are analyzed to detect the touch position of the surface of the input device. As a person skilled in the art can readily understand the related operations of the steps shown in  FIG. 5  after reading the above-mentioned description directed to the input device  300  shown in  FIG. 3 , further description is omitted here for brevity. 
         [0039]    In summary, exemplary embodiments of the present invention provide an input device and a method for detecting a touch status of a surface of the input device. By utilizing a 2D image sensor and an optical device preferably implemented to spread a size of an image to be formed on the 2D image sensor, the touch status can be detected by the sensor rows of the 2D image sensor. Then, the exemplary embodiments of present invention provide a row by row readout sequence to increase the refresh rate and detect the touch position of the input device. Furthermore, an extensible device is added into the input device to have contact with the surface of the input device; therefore, the touch pressure of the input device can be detected by utilizing a group by group readout sequence. 
         [0040]    Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.