Abstract:
A touch display device includes an interferometric modulator display panel and a processor. The display panel includes a plurality of pixel units. The pixel units each includes a fixed mirror including a reflective surface, at least one spacer, a transmovable mirror and at least one sensor. The at least one spacer is arranged between the fixed mirror and the movable mirror, the movable mirror is spaced an adjustable distance from the fixed mirror, and the movable mirror reflects a first portion of incident light and to allow a second portion of the incident light to pass therethrough. The at least one pressure sensor is fixed on the movable mirror and senses depression of the movable mirror caused by a touch thereon. The processor determines the touch position according to the generating signals from the sensors.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to display devices, especially to a touch sensitive interferometric modulator display device. 
         [0003]    2. Description of Related Art 
         [0004]    Touch sensitive displays, such as resistive and capacitive, infrared type, electrostatic inductive, have been commonly used. A touch sensitive display typically includes a display panel and a plastic substrate. Lines are arranged on the plastic substrate, and an integrated circuit is connected with the lines and a controller. The plastic substrate is integrated on the display panel. One problem with such conventional touch sensitive display is that the sensitivity of such display is limited because of the lines that cross with each other. Rather it is difficult for the display to be made thin enough to allow for miniaturization. 
         [0005]    Therefore, what is needed is a touch sensitive display device to overcome the above mentioned limitations. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0007]      FIG. 1  is a schematic view of a touch sensitive display device in accordance with an exemplary embodiment. 
           [0008]      FIG. 2  is a schematic, cross-sectional view showing a pixel unit of the touch sensitive display device of  FIG. 1  in accordance with a first exemplary embodiment. 
           [0009]      FIG. 3  is a schematic view showing spacers of a pixel unit of the touch sensitive display device of  FIG. 2 . 
           [0010]      FIG. 4  is a schematic view showing that a pixel unit of the touch sensitive display device of  FIG. 2  is depressed by a user. 
           [0011]      FIG. 5  is a cross-sectional view of a pixel unit of the touch sensitive display device of  FIG. 1  in accordance with a second exemplary embodiment. 
           [0012]      FIG. 6  is a schematic view showing that a pixel unit of the touch sensitive display device of  FIG. 5  is depressed by a user. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    The disclosure, including the accompanying drawings, is illustrated by way of example and not by way of limitation. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. 
         [0014]    Referring to  FIGS. 1-3 , a touch sensitive display device  100  is illustrated. The touch display device  100  includes a housing  10 , a display panel  20  and a processor  30 . The display panel  20  is framed within the housing  10 ; the processor  30  is fixed in the housing  10  and is electrically connected to the display panel  20 . 
         [0015]    The display panel  20  is an interferometric modulator display panel and includes a plurality of pixel units  21 . Each pixel unit  21  includes a substrate  201 , at least one spacer  202 , a reflective element  203  and at least one pressure sensor  204 . The substrate  201  is a fixed mirror and the reflective element  203  is a transmovable mirror. The reflective element  203  is made of deformable, transflective membrane. In an embodiment, the reflective element  203  is an integral part of the pixel unit  21 . In another embodiment, the reflective element  203  may include a number of independent reflective units, each reflective unit is placed on one pixel unit  21 . 
         [0016]    High reflection film is coated on the inner surface of the substrate  201  for reflecting light. In the embodiment, the high reflection film can be a metal reflective coating chosen from the group consisting of an aluminum coating, a gold coating and a silver coating. The reflective element  203  is spaced a variable and controllable distance from the substrate  201  by the spacers  202 . The contact area of the spacers  202  with the substrate  201  and reflective element  203  is far smaller than the substrate  201  and reflective element  203  for enhancing the incidence light. A portion of incident light is reflected by the reflective element  203 , and the rest of the incident light penetrates the reflective element  203  and is reflected by the substrate  201  to the reflective element  203 . When the light reflected by the substrate  201  and reflective element  203  recombines, they generate interference phenomenon, causing the pixel units  21  to display a color that depends on the difference between the distances they traveled. Namely, the distance between the substrate  201  and the reflective element  203  determines the color displayed by the pixel units  21 . 
         [0017]    In the embodiment, the thickness of the spacer  202  is defined as “D”, and thus the distance between the substrate  201  and the reflective element  203  spaced by the spacer  202  is “D”. The wavelength of the incidence light is defined as “λ”. In order to form a light interference described above, the relationship of the thickness “D” of the spacer  202  and the wavelength “λ” of the incidence light needs to satisfy “2d=Nλ”, where N is natural number 1, 2, 3 . . . . 
         [0018]    The sensor  204  is fixed on the viewing side of the reflective element  203  and is electrically connected to the processor  30 . The viewing side means a side facing a user when he/she views the content displayed on the display  100 . That is, the pressure sensors  204  are fixed on the side of the reflective element  203  that is opposite to the spacer  202 . The pressure sensors  204  are piezoresistive or piezoelectric. 
         [0019]    Referring to  FIG. 4 , when a touch from a user is applied on the reflective element  203 , the reflective element  203  is deformed and further causes the pressure sensors  204  fixed on the reflective element  203  to be deformed due to reacting force from the spacer  202 . The pressure sensors  204  then generate sensing signals. The processor  30  receives the sensing signals and determines which pressure sensors  204  transmit the signals to processor  30  and determines the touched pixel units  21 . As a result, the processor  30  can determine a touched area/position where the user touches the display device  100 . 
         [0020]    In a first embodiment, each pixel unit  21  includes four spacers  202  and four pressure sensors  204 . The four spacers  202  are fixed on four edges of the substrate  201  and abut against or support the reflective element  203 . The four pressure sensors  204  are arranged on the position where the deformation of the reflective element  203  can be easily detected. In the embodiment, the pressure sensors  204  are arranged adjacent to the position where the spacers  202  and the reflective element  203  are joined. The four pressure sensors  204  are set to correspond to the pixel unit  21 , that is, the processor  30  identifies one touched pixel unit  21  when any one of the four pressure sensors  204  have detected deformation. Each pixel unit  21  is assigned a coordinate value, such that the processor  30  can determine the positions of each pixel unit  21  and can determine a touched area/position based on the pixel units  21  whose pressure sensors  204  have detected deformation. 
         [0021]    In another embodiment, the number of the spacers  202  may be two, and the spacers  202  may be fixed on substrate  201  of one pixel unit  21  at diagonal corners of the substrate  201  and abuts against or supports the reflective element  203 . The number of the sensors may be two. 
         [0022]    In another embodiment, the number of the spacers  202  may be one, and the spacer  202  may be fixed on the center of the substrate  201 . The number of the pressure sensors  204  may be one and may be fixed on center of the reflective element  203 . 
         [0023]    Referring to  FIGS. 5-6 , in a second embodiment, pixel units  21   c  each include a substrate  201   c , four spacers  202   c , a reflective element  203   c , four pressure sensors  204   c  and a soft panel  205   c . The soft panel  205   c  is flexible and is capable of being deformed under external force. The reflective element  203   c  is made of deformable, transflective membrane. The four spacers  202   c  are fixed on the middle of four edge of the substrate  201   c . The pressure sensors  204   c  are fixed on the reflective element  203   c  and electrically connected to the processor  30 . The four pressure sensors  204   c  are respectively arranged right above the four spacers  202   c  and are set to correspond to one pixel unit  21   c.    
         [0024]    The soft panel  205   c  is fixed on the reflectively panel  203   c , and includes a number of knobs  206  residing on the pressure sensors  204   c . When the soft panel  205   c  is depressed, the knobs  206  push the pressure sensors  204   c  and the pressure sensors  204   c  can detect the pressure from the knobs  206 . With the soft panel  205   c  having knobs  206  on the reflective element  203   c , the sensors pressure  204   c  can more easily detect a touch on the display device  100  because the depression from a user will be transmitted to the pressure sensors  204   c  through the knobs  206 . In addition, the soft panel  205  can protect the reflective element  203   c  from being damaged because the pressure is evenly distributed to the reflective element  203   c  through the knobs  206 . 
         [0025]    In another embodiment, the number of the spacers  202   c  may be one or two, and the number of the knobs  206  of the soft board  205   c  and the pressure sensors  204   c  may correspond to the number of the spacers  202   c . In this embodiment, there is at least one knobs  206  that abuts against one of the pressure sensors  204   c.    
         [0026]    If the number of the spacer  202   c  is one, the spacers  202   c  is fixed on center of the substrate  201   c  to support the reflective element  203   c , and the number of the pressure sensors  204   c  is also one. The sensor pressure  204   c  is fixed on the center of the reflective element  203   c  corresponding the spacer  202   c . In the embodiment, each boss  206  abuts against one sensor  204   c.    
         [0027]    If the number of the spacers  202   c  is two, the spacers  202   c  are fixed on substrate  201   c  at diagonal corners of the substrate  201  to support the reflective element  203   c , and the number of the pressure sensors  204   c  is also two. The sensors  204   c  are fixed on reflective element  203   c  corresponding the spacers  202   c . Each of the knobs  206  of the soft panel  205   c  abuts against one sensor  204   c.    
         [0028]    It is to be understood, however, that even though numerous characteristics and advantages of the present disclosure have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the present disclosure is illustrative only, and changes may be made in detail, especially in the matters of shape, size, and arrangement of parts within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.