Patent Publication Number: US-2007097704-A1

Title: Touch-controlled backlight module

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention is related to a touch-controlled backlight module, and more particularly to a touch-controlled backlight module in which a tablet module is arranged for responding to a signal of a nearby electronic pen to output a corresponding signal.  
      2. Description of the Prior Art  
      The existent liquid crystal module includes a glass layer of an LCD and a backlight module arranged on rear side of the glass layer. The backlight module includes a light guide board, a light-emitting unit, a reflective board and a scattering board. The light emitted from the light-emitting unit passes through the light guide board to be uniformly outward scattered by the scattering board to rear side of the glass layer of the LCD. After assembled, the liquid crystal module is installable in the housing of a panel as one piece to form a liquid crystal panel.  
      The above liquid crystal module simply serves to show images. A user is unable to directly use an electronic pen to touch the glass layer of the LCD and achieve necessary functions. To improve this, some manufacturers remove the circuit board from rear side of the liquid crystal module and add a tablet module to the rear side of the liquid crystal module. Some other manufacturers remove the backlight module and add a tablet module to the liquid crystal module to achieve touch-controlled functions. Accordingly, the liquid crystal module is responsive of the signal of an electronic pen to emit a corresponding signal.  
      However, such assembly has some shortcomings as follows:  
      1. The backlight module has been tested. After the backlight module is re-disassembled and reassembled, the backlight module may be displaced from its true position. Also, the circuit may be opened to lead to defective product. Therefore, the ratio of good products can be hardly enhanced and the manufacturing cost is increased.  
      2. The liquid crystal module may be produced by a different manufacturer. Under such circumstance, the tests and rectifications of the liquid crystal module and the tablet module are not unified. As a result, when the tablet module is added to the back face of the liquid crystal module, the tablet module is subject to electromagnetic interference of the liquid crystal module. Therefore, when an electronic pen gets close to the liquid crystal module, the tablet module can hardly truly respond to the signal of the electronic pen. This greatly increases the possibility of misjudging the signal and lowers the quality of the product.  
     SUMMARY OF THE INVENTION  
      It is therefore a primary object of the present invention to provide a touch-controlled backlight module including: a light guide board; at least one light-emitting unit for projecting light to an incident surface of the light guide board; and a reflective board positioned on rear side of the light guide board for reflecting the light coming from the light guide board back to the light guide board. A tablet module is laid on rear side of the reflective board. When released from a factory, the tablet module, the light guide board, the light-emitting unit and the reflective board are assembled to form a complete module. The tablet module is responsive of a signal of a nearby electronic pen to output a corresponding signal without affecting the original display function.  
      A scattering board is disposed on outer side of the front surface of the light guide board for uniformly scattering the light coming from the light guide board. At least one brightening board is disposed on outer side of the scattering boards for enhancing the light signal. Another scattering board is further overlaid on outer side of the outermost brightening board for uniformly outward scattering the light coming from the outermost brightening board.  
      It is a further object of the present invention to provide a touch-controlled backlight module including: a light guide board; a light-emitting unit for projecting light to an incident surface of the light guide board; a reflective board positioned on rear side of the light guide board for reflecting the light coming from the light guide board back to the light guide board; and a glass layer of an LCD. The glass layer is arranged on outer side of the light guide board. A tablet module is laid on rear side of the reflective board. When released from a factory, the tablet module, the light guide board, the light-emitting unit, the reflective board and the glass layer of the LCD are assembled to form a complete module, whereby the tablet module is responsive of a signal of a nearby electronic pen to output a corresponding signal. The light guide board, the light-emitting unit, the reflective board, the glass layer of the LCD and the tablet module are assembled to form a touch-controlled liquid crystal module.  
      It is still a further object of the present invention to provide the above touch-controlled backlight module which can be installed on rear side of the glass layer of the LCD. The light emitted from the light source passes through the light guide board to be scattered by the outermost scattering board to the glass layer of the LCD. When an electronic pen gets close to or touches the glass layer of the LCD, the tablet module is triggered to emit a corresponding signal.  
      The present invention can be best understood through the following description and accompanying drawings wherein: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of the present invention;  
       FIG. 2  is a side view of the present invention;  
       FIG. 3  is a side view of the complete touch-controlled backlight module of the present invention;  
       FIG. 4  is a side view of the touch-controlled backlight module of the present invention, in which the glass layer of the LCD is included; and  
       FIG. 5  is a side view of the touch-controlled backlight module of the present invention, which is installed on rear side of the glass layer of the LCD. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Please refer to FIGS.  1  to  5 . The touch-controlled backlight module  100  of the present invention includes a light guide board  10 , at least one light-emitting unit  20  for projecting light to the incident surface  11  of the light guide board  10  and a reflective board  30  positioned on rear side of the light guide board  10  for reflecting the light coming from the light guide board  10  back to the light guide board  10 . A tablet module  50  is laid on rear side of the reflective board  30 . When released from the factory, the tablet module  50 , the light guide board  10 , the light-emitting unit  20  and the reflective board  30  are assembled to form a complete module. The module is responsive of the signal of a nearby electronic pen to output a corresponding signal without affecting the original display function.  
      The touch-controlled backlight module  100  of the present invention further includes a scattering board  40  disposed on outer side of the front surface  12  of the light guide board  10  for uniformly scattering the light coming from the light guide board  10 .  
      The light-emitting unit  20  of the touch-controlled backlight module  100  includes a light-emitting cell  21  such as cold cathode fluorescent lamp (CCFL) and a reflective shade  22 . The light-emitting cell  21  is arranged on one side of the light guide board  10 , facing the incident surface  11  thereof. The reflective shade  22  is arranged on one side of the light-emitting cell  21  for focusing the light emitted from the light-emitting cell  21  onto the light guide board  10 . The light-emitting unit  20  pertains to prior art and will not be further described hereinafter. Any other conventional light-emitting unit is also applicable to the present invention.  
      Referring to  FIG. 3 , the touch-controlled backlight module  100  of the present invention further includes a frame body  80  for enclosing and fixing the light guide board  10 , the light-emitting unit  20 , the reflective board  30 , the scattering boards  40 ,  40 ′, the tablet module  50  and brightening boards  60 ,  60 ′ to form a firm and complete touch-controlled backlight module  100 .  
      The touch-controlled backlight module  100  of the present invention further includes at least one brightening board  60 ,  60 ′ disposed on outer side of the scattering boards  40  for enhancing the light signal. Another scattering board  40 ′ is further overlaid on outer side of the outermost brightening board  60 ′ for uniformly outward scattering the light coming from the outermost brightening board  60 ′ as the glass layer  70  of a liquid crystal display (LCD).  
      In the touch-controlled backlight module  100  of the present invention, the scattering boards  40 ,  40 ′ and the brightening boards  60 ,  60 ′ can be omitted. Alternatively, only one or more scattering board  40 ,  40 ′ are disposed on the front surface  12  of the light guide board  10 . Alternatively, only one or more brightening board  60 ,  60 ′ are disposed on the front surface  12  of the light guide board  10 . Alternatively, a scattering board  40  and at least one brightening board  60  are dispose on the front surface  12  of the light guide board  10 . Still alternatively, a brightening board  60  and at least one scattering board  40  are dispose on the front surface  12  of the light guide board  10 . The combination and permutation as well as the position and number of the scattering boards  40 ,  40 ′ and the brightening boards  60 ,  60 ′ are not limited.  
      The touch-controlled backlight module  100  of the present invention includes the light guide board  10 , the light-emitting unit  20 , the reflective board  30  and the tablet module  50  mounted on rear side of the reflective board  30 . The module  100  can be installed on rear side of the glass layer  70  of the LCD. When released from the factory, the light guide board  10 , the light-emitting unit  20 , the reflective board  30 , the tablet module  50  and the glass layer  70  of the LCD are assembled to form a complete module. The module is responsive of the signal of a nearby electronic pen to output a corresponding signal. The light guide board  10 , the light-emitting unit  20 , the reflective board  30 , the glass layer  70  of the LCD and the tablet module  50  are assembled to form a touch-controlled liquid crystal module (LCM). The touch-controlled backlight module  100  of the present invention is installed on rear side of the glass layer  70  of the LCD. The light emitted from the light source passes through the light guide board  10  to be scattered by the outermost scattering board  40 ′ to the glass layer  70  of the LCD. When a corresponding electronic pen (not shown) gets close to or touches the glass layer  70 , the tablet module  50  is triggered to emit a signal. The touch-controlled liquid crystal module is applicable to liquid crystal display, liquid crystal handwriting board, write-read board, etc.  
      Referring to  FIG. 4 , the glass layer  70  of the LCD can be also enclosed in the frame body  80  of the touch-controlled backlight module  100  when assembled. Alternatively, as shown in  FIG. 5 , the glass layer  70  of the LCD is simply fixed on outer side of the touch-controlled backlight module  100  and an outer frame  80 ′ is further used to tightly bind the glass layer  70  of the LCD with the touch-controlled backlight module  100 . Accordingly, when the touch-controlled backlight module  100  with or without the glass layer  70  of the LCD is sent to a downstream LCM assembling procedure, the touch-controlled backlight module  100  will not be re-disassembled. Therefore, the possibility of human damage to the touch-controlled backlight module  100  is minimized. Moreover, the components of the touch-controlled backlight module  100 , such as the light-emitting unit  20 , the light guide board  10 , the reflective board  30  and the glass layer  70  of the LCD have been rectified to obviate any possible interference and error. Therefore, the tablet module  50  of the touch-controlled backlight module  100  can more truly respond to the electronic pen to emit the signal. Accordingly, the ratio of good products is enhanced.  
      The above embodiments are only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the above embodiments can be made without departing from the spirit of the present invention.