Abstract:
Display devices and methods forming the same. A digitizer sensor board is integrated on an upper substrate or a lower substrate of a display panel to provide a display device. In the display device, the display panel displays images, and the digitizer sensor board is integrated into the display panel to sense position of a position pointer or finger contact on a surface.

Description:
BACKGROUND 
     The invention relates to display devices, and more particularly, to display systems with digitizers. 
     Many types of touch sensitive computer input devices are currently touched on or in conjunction with computer displays. Such devices detect the position of a position pointer or finger contact on the sensor surface. The position coordinates are generated for interaction with the computer, for example in selecting icons on the display, menu items, editing images, or feedback for input of hand-drawn characters and graphics. 
     Numbers of technologies can be used for such devices, including capacitive sensing, resistive sensing using a conductive overlay sheet, infrared sensing, acoustic wave sensing, and piezoelectric force sensing. One of such device like digitizers which use hardwired handheld position pointer such as pens typically use electromagnetic, electrostatic, resistive, or sonic pulse sensing. 
     These input devices responsive to human contact are typically used for cursor control, such as selection of display icons and menu items. Other input devices responsive to position pointer (usually a hardwired pen) are used to create or trace drawings, blueprints, or original art. These devices are also used for character or handwriting recognition. It is therefore desirable that the sensor reproduce the path of the position pointer by some visual means to provide visual feedback. 
     Some of these input devices are responsive to both user and position pointer contact, thereby providing the convenience of position pointer-based input, for example when writing on the screen, as well as the ease of touch input, which does not require position pointer. 
       FIG. 1  is a structural diagram of a conventional display device with a digitizer. As shown, the display device  200  comprises a top glass cover  210 , liquid crystal display (LCD) panel  220 , a backlighting module  230 , a reflector  240 , digitizer sensor board  250 , a shield film  260 , a back frame  270  and a position pointer  280 . The top glass cover  210 , the LCD panel  220 , the backlighting module  230 , the reflector  240 , the digitizer sensor board  250 , the shield film  260  and the back frame  270  are assembled as a laminated construction. The LCD panel  220  and the digitizer sensor board  250  are coupled to an external host system via differential interfaces, such as two flexible printed circuit boards (FPCs).  FIG. 2  is a block diagram of a conventional display system with a digitizer. As shown, display system  100  comprises LCD module  220  and digitizer module  250 . The LCD module  220  and the digitizer module  250  are coupled to the host system  130  via corresponding interfaces  112  and  122  respectively. The digitizer module  250  requires an oscillator  124  disposed in the microcontroller  126  to generate scan timing signals (SS) for the selection circuit  128 , thereby performing scan operation of sensor array  129 . Because the reflector, the digitizer sensor board, a shield film and a back frame in the conventional display system are separate components and the LCD module and the digitizer module require differential interfaces coupled to an external host system, the conventional display system presents increased costs, thickness, and weight. 
     SUMMARY 
     The invention is directed to provide a display device that integrates a digitizer sensor board on a LCD module so as to lower thickness and weight. 
     In one aspect of the invention, a LCD module displays image, and a digitizer sensor board integrated on the surface of the substrate of the LCD module senses position of a position pointer or finger contact on a surface. 
     In a further aspect, the invention discloses an embodiment of a display system, in which the disclosed display device displays images and senses position of a position pointer or finger contact on a surface, and with a shield film laminate on the display system to screen external noise. 
     In another aspect, the invention discloses an embodiment of an electronic device, in which the disclosed display system displays images and senses position of a position pointer or finger contact on a surface, and a DC/DC converter is operatively coupled to the display system, powering the display system to display images and sense position of a position pointer or finger contact on a surface. 
     In another aspect, the invention discloses an embodiment of a fabrication method of a display device, in which a digitizer sensor board is formed on a glass substrate to serve as an upper substrate of a display device. A thin film transistor (TFT) array substrate is formed on lower substrate of the display device. The upper substrate and the lower substrate of the display device are assembled. 
     In a further aspect, the invention discloses an embodiment of another fabrication method of a display device, in which a digitizer sensor board is formed on a glass substrate. A thin film transistor (TFT) array is formed on the digitizer sensor board, such that the TFT array and the digitizer sensor board on the glass substrate serve as a lower substrate of a LCD module. An upper substrate of the LCD module is formed and the upper substrate and the lower substrate of the LCD module are assembled. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by the subsequent detailed description and examples with reference made to the accompanying drawings, wherein: 
         FIG. 1  is a structural diagram of a conventional display device with digitizer sensor board; 
         FIG. 2  is a block diagram of a conventional display system with a digitizer; 
         FIG. 3A  shows a first embodiment of a display device; 
         FIG. 3B  shows a second embodiment of a display device; 
         FIG. 4  is a block diagram of a display device according to the invention; 
         FIG. 5  is a block diagram of an embodiment of a display system; 
         FIG. 6  shows an embodiment of a timing controller; and 
         FIG. 7  schematically shows an electronic device incorporating a display system in accordance with embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 3A  shows a first embodiment of a display device. As shown, the display device  400 A comprises a top glass cover  410 , a display panel  420 , a backlight module  430 , a reflector  440 , a shield film  460  and a back frame  470 . The top glass cover  410 , the backlight module  430 , the reflector  440 , the shield film  460  and the back frame  470  are laminated with the display panel  420  in the display device  400 A. In this embodiment, the LCD module  428  is not limited to LCD. The display panel  420  comprises a LCD display module  428  and a digitizer sensor film  453  integrated on a surface of a glass substrate  452  of the LCD module  428 . 
     The LCD module  428  comprises an upper substrate  422 , a lower substrate  424 , and a liquid crystal layer  455 , in which the upper substrate  422  comprises a color filter layer  454 , a digitizer sensor board  426 , and a polarizer  450  and the lower substrate  424  comprises a thin film transistor (TFT) array  456 , a glass substrate  457  and a polarizer  458 . Typically, the color filter layer  454  comprises a black matrix (BM) and a plurality of color coated films (CCF) formed therein, the black matrix BM resulting in a non-transparent area in the LCD module  428 . The LCD module  428  also can be an organic light-emitting diode (OLED) display module or a field emission display (FED) module, although it is to be understood that the invention is not limited thereto. In some display systems, the backlight module  430 , the reflector  440  or the color filter  454  can be omitted. 
     The digitizer sensor board  426  comprises a glass substrate  452  and a digitizer sensor film  453  formed thereon, with the digitizer sensor board  426  integrated with the color filter layer  454  of the LCD module  428 . The digitizer sensor board  426  can be a capacitive digitizer sensor board, a resistive digitizer sensor board, an infrared digitizer sensor board, an acoustic wave digitizer sensor board, a piezoelectric force digitizer sensor board, an electrostatic digitizer sensor board or a sonic pulse digitizer sensor board. 
     For example, the digitizer sensor film  453  can comprise a sensor array, metal coils, metal grids or conductor wires formed on the glass substrate  452 , in which in the sensor array, metal coils, metal grids or conductor are formed in the non-transparent area, thereby avoiding decrease in aperture ratio of the display panel. In some examples, the sensor array, metal coils, metal grids or conductive wires can be printed on the bottom surface of the glass substrate  452  by screen-printing, ink-jet printing or deposition. For example, conductive metal pastes or inks, such as Ag or Cu based formulations, can be used for screen-printing or ink-jet printing. 
       FIG. 3B  shows a second embodiment of a display device. The display device  400 B comprises a top glass cover  410 , a display panel  420 , a backlight module  430 , a reflector  440 , a shield film  460  and a back frame  470 . As shown, unlike the first embodiment, the digital sensor board  426  is integrated on the lower substrate of the LCD module  428 . 
     The LCD module  428  comprises an upper substrate  422  with a color filter layer  454  and a glass substrate  442 , a lower substrate  424 , and a liquid crystal layer  455  formed between the upper substrate and the lower substrate. The lower substrate  424  comprises a thin film transistor (TFT) array  456 , a SiO 2  layer  457  and a polarizer  458 . The LCD module  428  can also be an organic light-emitting diode (OLED) display module or a field emission display (FED) module, although it is to be understood that the invention is not limited thereto. In some display systems, the backlight module  430 , the reflector  440  or the color filter layer  454  can be omitted. 
     The digitizer sensor board  426  comprises a glass substrate  452  and a digitizer sensor film  453  formed thereon. The digitizer sensor board  426  is integrated on the lower substrate of LCD module  428 . 
     The present invention also discloses a fabrication method for a display panel  420 . In this method, a digitizer sensor film is formed on a glass substrate to serve as an upper substrate of a display panel. For example, the digitizer sensor film  453  can be formed on the glass substrate  452  and the color filter  454  is then formed on the digitizer sensor film  453 , as shown in  FIG. 3A . A polarizer  458  is formed on the glass substrate  452 , and a dielectric layer is formed between the color filter  454  and the digitizer sensor film  453  if needed. The digitizer sensor board  426  comprises the digitizer sensor film  453  and the glass substrate  452 . Namely, the digitizer sensor board  426  is integrated on the upper substrate of the LCD module  428 . 
     A thin film transistor (TFT) array substrate is formed to serve as a lower substrate of the display panel. For example, the TFT array  456  is formed on the glass substrate  457  to serve as a lower substrate  424  of the display panel  428 , in which a polarizer  458  is formed on the glass substrate  457  if needed. 
     The upper substrate and the lower substrate of the LCD module  428  are assembled into a display panel  420 . The LCD module  428  can also be an organic light-emitting diode (OLED) display module or a field emission display (FED) module, although it is to be understood that the invention is not limited thereto. 
     Liquid crystal material is injected between the upper substrate and the lower substrate to form a liquid crystal layer  455  after the upper substrate and the lower substrate are assembled. 
     The invention also discloses another fabrication method for a display panel. In this method, a digitizer sensor board is formed on a glass substrate and a TFT array  456  is formed on the digitizer sensor board. For example, the digitizer sensor film  453  can be formed on the glass substrate  452 , a SiO 2  layer  457  can be formed on the digitizer sensor film  453  and a thin film transistor (TFT) array  456  can be formed on the SiO 2  layer  457 , as shown in  FIG. 3B , in which a polarizer  458  is formed on the glass substrate  452  if needed. The digitizer sensor board  426 , the SiO 2  layer  457  and the TFT array  456  serve as the lower substrate of the display panel  428 . Namely, the digitizer sensor board  426  is integrated on the lower substrate of the display panel  420 . 
     An upper substrate of the LCD module  428  is formed. For example, the color filter  454  laminated with the polarizer  451  can serve as the upper substrate of the display panel, as shown in  FIG. 3B . 
     The upper substrate and the lower substrate of the LCD module  428  are assembled to a display panel  420 . The LCD module  428  can be a liquid crystal display (LCD) module, an organic light-emitting diode (OLED) display module or a field emission display (FED) module, although it is to be understood that the invention is not limited thereto. 
     Because the LCD module  428  shown in  FIG. 3B  is an LCD module, liquid crystal material is injected between the upper substrate and the lower substrate to from a liquid crystal layer  455  after the upper substrate and the lower substrate are assembled. 
       FIG. 4  shows an embodiment of a display device. As shown, the display device  400 C comprises a top glass cover  410 , a display panel  420 , a backlighting module  430 , a reflector  440 , a shield board  460  and a back frame  470 . The display panel  420  is coupled to an external host system via a single interface  310 , such as a flexible printed circuit board (FPC). The display panel  420  comprises a display module and a digitizer sensor board integrated in the display module. A control unit  482  is mounted on the flexible printed circuit board to drive the display module and generate a scan timing signal SS to the digitizer sensor board according to an image signal from the host system via the interface. The display panel  420  executes a scan operation to generate position data in response to the scan timing signal, the control unit  482  determines the corresponding coordinate data of the position pointer  480  according to the position data for output to the host system. The control unit  482  can also, for example, be a chip on glass of the LCD module  428 . 
     In embodiments of the invention, the LCD module  428  can also be a liquid crystal display (LCD) module, an organic light-emitting diode (OLED) module, or a field emission display (FED) module, but it is to be understood that the invention is not limited thereto. 
     The digitizer sensor board  426  in the display panel  420  can be a capacitive sensing digitizer board, a resistive sensing digitizer board, an infrared sensing digitizer board, an acoustic wave sensing digitizer board, or a piezoelectric force sensing digitizer board, an electrostatic sensing digitizer board, or a sonic pulse sensing digitizer board. 
     Because the display system of the embodiment of the invention requires only a display panel integrated with a display module and a digitizer sensor board, thickness and weight are less than a conventional display system with separate components. 
       FIG. 5  is a block diagram of an embodiment of a display system. The display system  400 D comprises an interface  310 , the control unit  482 , the described digitizer module  426  and the described LCD module  428 . 
     The interface  310  is coupled between the host system  600  and the control unit  482 , to exchange data with the host system  600 . 
     The control unit  482  is coupled to the interface  310 , the LCD module  428  and the digitizer module  426 . The control unit  482  drives the LCD module  428  and generates a scan timing signal (SS) to the digitizer module  426  according to an image signal (IS) from the host system  600  via the interface  310 . The control unit  482  comprises a timing controller  322 , an analog-to-digital converter  324 , a voltage adjustment circuit  326  and a digital-to-analog converter (DAC)  328 . The control unit  482  also receives bus control signals (BCS) from the host system  600  via the interface  310 , controlling the operations of the ADC  324 , DAC  328  and the selection circuit  346 . 
     The timing controller  322  is coupled to the interface  310 , the LCD module  428  and the digitizer module  426 , generating a driving signal by the DAC  328  according to the image signal (IS) from the host system  600 . Typically, the image signal (IS) from the host system comprises image data (ID), a clock signal (CLKS) and common voltage Vcom, in which the clock signal CLKS includes a vertical scan signal Vs, a horizontal scan signal Hs, a data enable signal DE and a system clock CLK. The timing controller  322 , according to the clock signal CLKS of the image signal, provides reference timing signals comprising a vertical clock output CKV, a horizontal clock output CKH, a horizontal enable output ENBH, a vertical enable output ENBV, a horizontal scan direction CSH and a vertical scan direction CSV, for the LCD module  428 . The reference timing signal RTS and the image data ID serve as the driving signal and are output to the DAC  328  for conversion to analog signals driving the LCD module  428 . The voltage adjustment circuit  326  is coupled to the timing controller  322  and the LCD module  428 , adjusting the voltage level of the analog signal driving the LCD module  428  according to the common voltage Vcom. 
     Further, timing controller  322  generates the scan timing signal SS to the digitizer module  426  according to the image signal (IS) from the host system  600 . Because the frequency of scan timing signal (SS) required in the digitizer module  426  is between about 100 KHz and 300 KHz and the frequency of the clock signal CLKS in the image signal IS from the host system is typically between 5 MHz and 6 MHz, the embodiment down-converts the clock signal CLKS in the image signal from the host system to obtain a scan timing signal SS with a suitable frequency without utilizing an oscillator as a conventional digitizer board. Thus, in this embodiment, the digitizer module  426  and the LCD  428  are coupled to the host system  600  via a single interface. In this embodiment, timing controller  322  comprises a frequency divider  329  to convert the clock signal CLKS of the image signal IS to the scan timing signal SS at a frequency suitable for the digitizer module  426 . 
     The LCD module  428  is coupled to the control unit  482  to display images according to the analog signals from the DAC  328 . The LCD module  428  can also be an organic light-emitting diode (OLED) display module, or a field emission display (FED) module. 
     The digitizer module  426  is typically used for cursor control applications, such as selection of displayed icons and menu items, creating or tracing drawings or blueprints, or for character or handwriting recognition. In this embodiment, the digitizer module  426  is coupled to the host system  600  via the interface  310  and executes a scan operation to generate position data PD in response to the scan timing signal SS. The digitizer module  426  comprises a digitizer sensor array  342 , a selection circuit  346 , and an amplifier  348 . In some examples, the digitizer sensor array  342 , the selection circuit  346  and the amplifier  348  are formed on the flexible digitizer sensor film  442  shown in  FIG. 3 . Alternately, the selection circuit  346  and the amplifier  348  can be integrated to the control unit  482  (not shown). For example, the digitizer module  426  can be an electromagnetic sensing digitizer board, in which electromagnetic signals are transmitted from the position pointer  480  and sensed by the sensor array  342 . 
     The digitizer sensor array  342 , for example, comprises metal coil grids in both X and Y orientations, sensing the position of the position pointer. The position pointer transmits signals to the digitizer sensor array  342 , and the selection circuit  346  scans the coils in the sensor array  342  according to the scan timing signal SS from the control unit  482 , such that signals induced in the digitizer sensor array  342  are sent to the amplifier  348 , and the amplifier  348  amplifies the induced signals in the digitizer sensor array  342 . 
     The amplified signals from the amplifier  348  are output to the ADC  324  and converted to position data PD to and then to the timing controller  322 . The timing controller  322  receives the position data PD relative to the position pointer  344  and determines the corresponding coordinate data CD of the digitizer sensor array  342  accordingly. The corresponding coordinate data CD of the digitizer sensor array  342  is then output to the host system  600  via the interface  310 . For example, the control unit  482  can be a single chip integrated by the timing controller  322 , the ADC  324 , the voltage adjustment circuit  326 , and the DAC  328 . The control unit  320  can be mounted directly on the display module  428  by chip on glass (SOG) process or mounted on a flexible printed circuit board (FPC) of the display module  428 . 
       FIG. 6  shows an embodiment of a timing controller. The timing controller  322  comprises a processing device  311 , a frequency divider (FD)  329 , a timing generator  332 , a data latch  333 , a register  334 , and a receiving and decoding device  335 , and receives the image signal IS and bus control signal BCS from the host system  600  via the interface  310 . 
     The processing device  331  is coupled to the ADC  324  to receive the position data PD and calculate the corresponding coordinate data CD for output to the host system  600  via the interface  310 . The host system  600  receives the coordinate data DC and converts to image signal to display on the display module. The frequency divider  329  converts the clock signal CLKS of the image signal to the scan timing signal SS with a suitable frequency, such as 100 KHz˜300 KHz, for the digitizer sensor board  426 . 
     The timing generator  332  also receives the clock signal CLKS to provide reference timing signals RTS for the display module  322 . The image data ID in the image signal from the host system  600  is temporarily stored by the data latch  333  and the register  334  and output to the DAC  328  to drive the display module  428 . The receiving and decoding device  335  receives the bus control signal BCS from the host system  600  to generate control data controlling operations of the DAC  328 , the ADC  324  and the selection circuit  346 . 
     Thus, the invention can use a single interface and integrate microprocessor  126  and the ADC  125  for digitizer sensor board and timing controller  127 , voltage adjustment circuit  132 , the DAC  131  for the LCD module shown in  FIG. 1  into single control unit, such that cost, thickness and weight of the display system are be reduced. 
       FIG. 7  schematically shows an electronic device  500  deploying the disclosed display systems. The display device  400 A/ 400 B/ 400 C/ 400 D can be a liquid crystal display system, an organic light-emitting diode (OLED) display system, or a field emission display (FED) system, although it is to be understood that the invention is not limited thereto. The electronic device  500  may be a portable device such as a PDA, notebook computer, tablet computer, cellular phone, or a display monitor device, etc. Generally, the electronic device  500  includes a housing  510 , the display system  400 A/ 400 B/ 400 C/ 400 D shown in  FIG. 4 , a DC/DC converter  520 , etc. Further, the DC/DC converter  520  is operatively coupled to the display system  400 A/ 400 B/ 400 C/ 400 D and provides an output voltage powering the display system  400 A/ 400 B/ 400 C/ 400 D to display images. 
     While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.