Abstract:
In the specification and drawing, an optical detection apparatus is described and shown with scanning devices, detectors, and a processing unit, wherein the scanning devices are positioned to scan a detection region with different light wavelengths.

Description:
BACKGROUND 
       [0001]    1. Field of Invention 
         [0002]    The present disclosure relates to a touch panel. More particularly, the present disclosure relates to a touch panel including optical detection means. 
         [0003]    2. Description of Related Art 
         [0004]    “Touch panel” is a device that can detect the presence and location of a touch within the detection region. Various types of touch panel, such as a resistive touch panel, a capacitive touch panel, and an optical touch panel, have been developed for such purpose. 
         [0005]    One embodiment of the present invention relates to a touch panel including optical detecting means. 
       SUMMARY 
       [0006]    According to one embodiment of the present invention, an optical detection apparatus includes a first and second scanning devices, a first and second detectors, and a processing unit. The first and second scanning devices are respectively positioned to scan a detection region with a first and second light beams, in which incident angles of the first and second light beams respectively vary with time and the wavelength of the first light beam is different from the wavelength of the second light beam. The first and second detectors are respectively positioned to detect a first and second time signals upon which the first and second light beams are respectively reflected by a touch within the detection region. The processing unit is operative to determine a location of the touch within the detection region by the first and second time signals and the incident angles of the first and second light beams by way of triangulation. 
         [0007]    According to another embodiment of the present invention, an optical detection method includes the following steps of: 
         [0008]    (1) scanning a detection region respectively with a first and second light beams, in which incident angles of the first and second light beams respectively vary with time, and the wavelength of the first light beam is different from the wavelength of the second light beam; 
         [0009]    (2) detecting a first and second time signals upon which the first and second light beams are respectively reflected by a touch within the detection region; and 
         [0010]    (3) determining a location of the touch within the detection region by the first and second time signals, and the incident angles of the first and second light beams by way of triangulation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a front view of an optical detection apparatus according to one embodiment of the present invention; 
           [0012]      FIG. 2  is a graph of the incident angle of the first light beam versus time; 
           [0013]      FIG. 3  is a graph of the first time signal versus time; and 
           [0014]      FIG. 4  is a three dimensional view of an optical detection apparatus according to another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
         [0016]      FIG. 1  is a front view of an optical detection apparatus  100  according to one embodiment of the present invention. The optical detection apparatus  100  includes a first scanning device  110 , a second scanning device  120 , a first detector  130 , a second detector  140  and a processing unit  150 . The first scanning device  110  is positioned to scan a detection region  500  with a first light beam F. The second scanning device  120  is positioned to scan the detection region  500  with a second light beam S. The wavelength of the first light beam F is different from the wavelength of the second light beam S. The first detector  130  is positioned to detect a first time signal upon which the first light beam F is reflected by a touch  300  within the detection region  500 . The second detector  140  is positioned to detect a second time signal upon which the second light beam S is reflected by the touch  300  within the detection region  500 . The processing unit  150  is operative to determine a location of the touch  300 . 
         [0017]    Specifically, the first scanning device  110  includes a light source  112 , a mirror  114  and a rotating actuator  116 . The light source  112  is operative to generate the first light beam F. The mirror  114  is positioned to receive the first light beam F and subsequently direct the first light beam F into the detection region  500 . The rotating actuator  116  is coupled to the mirror  114  for rotating the mirror  114  and thereby varying the incident angle α of the first light beam F in accordance with a driving signal provided by a controller, such as a motor controller integrated circuit (IC). That is, the incident angle α of the first light beam F can vary with time (as shown in  FIG. 2 ). 
         [0018]    Similarly, the second scanning device  120  includes a light source  122 , a mirror  124  and a rotating actuator  126 . The light source  122  is operative to generate the second light beam S. The mirror  124  is positioned to receive the second light beam S and subsequently direct the second light beam S into the detection region  500 . The rotating actuator  126  is coupled to the mirror  124  for rotating the mirror  124  and thereby varying the incident angle β of the second light beam S in accordance with a driving signal provided by a controller, such as a motor controller integrated circuit (IC). That is, the incident angle β of the second light beam S can vary with time as well. 
         [0019]    The light sources  112 / 122  may be laser diodes, for example 780 nm laser diodes (such as ADL-78101-TL available from Arima Lasers Corporation), 808 nm laser diodes (such as ADL-80Y01-TL available from Arima Lasers Corporation) or 850 nm laser diodes (such as ADL-85051-TL available from Arima Lasers Corporation), such that both the first light beam F and the second light beam S are collimated light beams. In the present embodiment, the light source  112  may be a 780 nm laser diode, and the light source  122  may be an 850 nm laser diode. Accordingly, the wavelength of the first light beam F is 780 nm, and the wavelength of the second light beam S is 850 nm. 
         [0020]    It is appreciated that many other devices may be used as the light sources  112 / 122 , for instance, light emitting diodes may be substituted for the laser diodes as the light sources  112 / 122 . 
         [0021]    The first scanning device  110  and the second scanning device  120  may be spaced apart from each other by a pre-determined distance. More particularly, the mirrors  114 / 124  may be spaced apart from each other by a pre-determined distance, for example the length L of the top side of the detection region  500 . 
         [0022]    The first detector  130  may include a narrow band pass filter  132  and a photodetector  134 . The narrow band pass filter  132  is positioned to distinguish the first light beam F from the second light beam S. The photodetector  134  is positioned to convert the first light beam F into the first time signal. As shown in  FIG. 3 , the first time signal may be a pulse, which indicates the time when the first light beam F is received by the photodetector  134 , i.e. the time when the first light beam F is reflected by the touch  300 . 
         [0023]    Similarly, the second detector  140  may include a narrow band pass filter  142  and a photodetector  144  as well. The narrow band pass filter  142  is positioned to distinguish the second light beam S from the first light beam F. The photodetector  144  is positioned to convert the second light beam S into the second time signal. The second time signal may also be a pulse, which indicates the time when the second light beam S is received by the photodetector  144 , i.e. the time when the second light beam S is reflected by the touch  300 . 
         [0024]    The photodetectors  134 / 144  may be photodiodes. It is appreciated that many other devices may be used as the photodetectors  134 / 144 , for instance, phototransistors may be substituted for the photodiodes as the photodetectors  134 / 144 . 
         [0025]    Since the incident angle α of the first light beam F is a function of time (as shown in  FIG. 2 ), if the time when the first light beam F is reflected by the touch  300  is known, then the incident angle α of the first light beam F at the time when the first light beam F is reflected by the touch  300  would be known as well. Furthermore, the incident angle β of the second light beam S at the time when the second light beam S is reflected by the touch  300  can be obtained by a similar way. 
         [0026]    The coordinates and distance to the touch  300  can be found by calculating the length L of the top side of the detection region  500 , given the incident angle α of the first light beam F at the time when the first light beam F is reflected by the touch  300  and the incident angle β of the second light beam S at the time when the second light beam S is reflected by the touch  300 . Specifically, the distance D between the top side of the detection region  500  and the touch  300  may be obtained by the following Formula I: 
         [0000]        D=U (1/tan α+1/tan β)   Formula I 
         [0027]    Thereafter, the distance LR between the right side of the detection region  500  and the touch  300  may be obtained by the following Formula II: 
         [0000]      LR=D cot β  Formula II 
         [0028]    Therefore, the location of the touch  300  may be described as (LR,D) by the Cartesian coordinate system. 
         [0029]    In use, the optical detection apparatus  100  may be integrated into a display panel  200  (as shown in  FIG. 1 ) or removably mounted on the display panel  200  (as shown in  FIG. 4 ). Accordingly, the optical detection apparatus  100  and the display panel  200  can be operative as a touch screen. 
         [0030]    As shown in  FIG. 4 , there may be a communication module  160  positioned to transmit the location of the touch to a computer  180 . The communication module  160  may be, for example, a human interface device (HID) bus, an universal serial bus (USB), a Bluetooth communication module or other wireless communication module. 
         [0031]    It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims.