Display systems with multifunctional digitizer module board

Display systems with multifunctional digitizer module board. A shield film is integrated on a digitizer sensor board to form a multifunctional digitizer module board with lower thickness and weight. In the multifunctional digitizer module, a digitizer sensor board senses position of a position pointer or finger contact on a surface and a shield film is integrated on one surface of the digitizer sensor board by semiconductor process to screen out external noise. A display panel is disposed above the multifunctional digitizer module board and coupled thereto, displaying images.

BACKGROUND

The invention relates to display systems, and more particularly, to display systems with multifunctional digitizer module board.

Many types of touch sensing devices, like digitizers etc. currently are used on or in conjunction with computer displays. Such touch sensing devices measure the position of position pointer or finger contact on the sensor surface and generates coordinates for interaction with the computer, for example in selecting icons on the display, menu items, editing images, and feedback for input of hand-drawn characters and graphics.

Such touch sensing devices may use any number of technologies, including capacitive sensing, resistive sensing using a conductive overlay sheet, infrared sensing, acoustic wave sensing, and piezoelectric force sensing. Digitizers which use hardwired handheld position pointer such as pens typically use electromagnetic, electrostatic, resistive, or sonic pulse sensing.

Touch sensing devices responsive to human contact are typically used for cursor control, such as selection of display icons and menu items or responsive to position pointer (usually a hardwired pen) are used to create or trace drawings, blueprints, or original art. These touch sensing devices are also used for character or handwriting recognition. It is therefore desirable that the touch sensing devices reproduce the path of the position pointer by some visual means to provide visual feedback.

Some of these touch sensing 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. 1is a structural diagram of a conventional display device with a digitizer. As shown, the display device200comprises a top glass cover210, the liquid crystal display (LCD) panel220, a back light module230, a reflector240, the digitizer sensor board250, a shield film260, a back frame270and a position pointer280. The top glass cover210, the LCD panel220, the back light module230, the reflector240, the digitizer sensor board250, the shield film260and the back frame270are assembled as a laminated construction, and the digitizer sensor board250and the position pointer280constructing a digitizer. The LCD panel220and the digitizer sensor board250are coupled to an external host system via differential interfaces, such as two flexible printed circuit boards (FPCs).FIG. 2is a circuit diagram of a conventional display system100which comprises LCD module110and digitizer module board120. The LCD module220and the digitizer module board120are coupled to the host system130via corresponding interfaces112and122respectively. The digitizer module board120requires an oscillator124disposed in the microcontroller126to generate scan timing signals (not shown) for the selection circuit128, thereby performing scan operation of digitizer sensor array129. 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 panel and the digitizer sensor board require differential interfaces coupled to an external host system, the conventional display system presents higher cost, thickness, and weight.

SUMMARY

The invention is directed to provide a multifunctional digitizer module board that integrates a shield film on a flexible digitizer sensor board without adhesive material so as to lower thickness and weight.

In one aspect of the invention, a flexible digitizer sensor board senses position of a position pointer or touch on a surface and a shield film is integrated on one surface of the digitizer sensor board by semiconductor process.

In another aspect, the invention discloses embodiments of a display system, in which a LCD panel displays images and a multifunctional digitizer module board disclosed here, senses position of a position pointer or finger contact on a surface.

In another aspect, the invention discloses embodiments of a fabrication method of a display system, in which a multifunctional digitizer module board comprising a flexible digitizer sensor board and a shield film is provided to sense position of a position pointer or finger contact on a surface, wherein the shield film is laminated with the digitizer sensor board without adhesive material. A LCD panel is disposed above the multifunctional digitizer module board.

DETAILED DESCRIPTION

FIG. 3shows an embodiment of a multifunctional digitizer module board.

As shown, the multifunctional digitizer module board440comprises a top protective film456, a reflective film454, a first protective film452, a flexible digitizer sensor board442, a second protective film444, a shield film446and a separator450,which the top protective film, the first and the second protective film can be SiOxor SiNx. In this embodiment, the top protection film456, the reflective film454, and the shield film446are integrated to the flexible digitizer sensor board442. In this case, the first protective film452is formed between the flexible digitizer sensor board442and the reflective film454and the second protective film444is formed between the shield film446and the flexible digitizer sensor board442by semiconductor process. The separator450is disposed on the shield film446by the adhesive material448.

The sensor for flexible digitizer sensor board442can be, for example, a capacitive sensor, a resistive sensor, an infrared sensor, an acoustic wave sensor, a piezoelectric force sensor, an electrostatic sensor, or a sonic pulse sensor, to sense position of a position pointer or finger contact on a surface. In some examples, the flexible digitizer sensor board442comprises a sensor array or metal coil grids printed on a flexible substrate, such as polyethylene terephthalate (PET) or cellulose triacetate (TAC). The sensor array or the metal coil grids can be printed on the flexible substrate by screen-printing for large patterns or ink-jet printing for small patterns, depending on design, but is not limited thereto. For example, conductive metal pastes or inks, such as Ag or Cu based formulations, can be used for screen-printing or ink-jet printing.

The second protective film444is formed on the bottom surface of the flexible digitizer sensor board442by semiconductor process. The shield film446is integrated on the surface of the second protective film444by semiconductor process to screen out external noise. The shield film446can be a thin metal foil with high magnetic susceptibility, such as Fe—Ni, Fe—Si or Fe—Co. The shield film446can be integrated on the surface of the protective film444by physical vapor deposition (PVD) or sputtering for high frequency applications.

The first protective film452is formed on the top surface of the flexible digitizer sensor film442by semiconductor process. The reflective film is formed on the surface of the first protective film452by semiconductor process, to reflect light. In this case, the first protective film452, the reflective film454, and top protective film456can be optional. In some examples, the reflective film454can also be deposited directly on the flexible digitizer sensor board442after planarizing the flexible digitizer sensor board442or depositing on a separate thin plastic substrate and then laminating with the flexible digitizer sensor board442. The reflective film454can be a thin metal foil, such as Al, Ag, alloy thereof, or different variations with optical reflection enhancement treatment.

The top protective film456, the reflective film454, and the shield film446are integrated to the flexible digitizer sensor board442by semiconductor process rather than adhesive material during assembly of the display device, and the separator450laminated with the shield film446by the adhesive material448.

Thus, the top protective film456, the reflective film454, the first protective film452, the shield film446, the flexible digitizer sensor board442, a second protective film444and the separator450form a single component for a display device. For example, the multifunction digitizer module board440can be applied to the back frame of a display device, immediately below the back light module, after removing the top protective film456and the separator450.

FIG. 4is a structural diagram of a display device400with a multifunctional digitizer module board according to an embodiment of the invention.

As shown, the display device400comprises a top glass cover410, a LCD panel420, a back light module430, the disclosed multifunctional digitizer module board440and a back frame460. The LCD panel420and the multifunctional digitizer module board440are coupled to an external host system via a single interface480, such as a flexible printed circuit board (FPC). The LCD panel420and the multifunctional digitizer module board440are connected by a flexible cable490. A control unit482is mounted on the flexible printed circuit board480to drive the LCD panel and generate a scan timing signal (SS) to the digitizer module board according to an image signal from the host system via the interface such as a flexible printed circuit board480. The multifunctional digitizer module board440executes a scan operation to generate position data (PD) in response to the scan timing signal (SS), the control unit482then determines the corresponding coordinate data (CD) of the position pointer344according to the position data for output to the host system. The control unit482can also, for example, be a chip on glass of the display panel420.

In the embodiments of the invention, the LCD panel420can also be an organic light-emitting diode (OLED) panel, or a field emission display (FED) panel, but it is to be understood that the invention is not limited thereto. The multifunctional digitizer module board440integrate the reflective film454, and the shield film446and the flexible digitizer sensor board442as shown inFIG. 3, therefore it can senses position of the position pointer344on the top glass cover410and also screens out external noise or reflects light. According to the flexible digitizer sensor board442therein, the multifunctional digitizer module board440can also be a capacitive sensing digitizer module board, a resistive sensing digitizer module board, an infrared sensing digitizer module board, an acoustic wave sensing digitizer module board, or a piezoelectric force sensing digitizer module board, an electrostatic sensing digitizer module board, or a sonic pulse sensing digitizer module board.

Because the display system of the embodiment of the invention requires only a flexible digitizer sensor board integrated with a shield film446and a reflective film454(if needed), it provides lower thickness and weight than a conventional display system with separate components.

FIG. 5is a circuit diagram of an embodiment of a display system300. The display system300comprises an interface480, the control unit482, the LCD panel420, and the multifunctional digitizer module board440.

The interface480is coupled between the host system600and the control unit482, to exchange data with the host system.

The control unit482is coupled to the interface480, the LCD panel420and the multifunctional digitizer module board440. The control unit482drives the LCD panel420and generates a scan timing signal (SS) to the multifunctional digitizer module board440according to an image signal (IS) from the host system600via the interface480. The control unit482comprises a timing controller322, an analog-to-digital converter324, a voltage adjustment circuit326and a digital-to-analog converter (DAC)328. The control unit482also receives bus control signals (BCS) from the host system600via the interface480, controlling the operations of the ADC324, DAC328and the selection circuit346.

The timing controller322is coupled to the interface480, the LCD panel420and the multifunctional digitizer module board440, generating a driving signal by the DAC328according to the image signal (IS) from the host system600. Typically, the image signal 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 controller322, according to the clock signal CLKS of the image signal, provides reference timing signals, such as 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 display panel420. The reference timing signal and the image data ID serve as the driving signal and are output to the DAC328for conversion to analog signals driving the display panel330. The voltage adjustment circuit326is coupled to the timing controller322and the display panel420, adjusting the voltage level analog signal driving the display panel420according to the common voltage Vcom.

Also, timing controller322generates the scan timing signal SS to the multifunctional digitizer module board440according to the image signal from the host system600. Because the frequency of scan timing signals required in the multifunctional digitizer module board is between about 100 KHz and 300 KHz and the frequency of the clock signal CLKS in the image signal from the host system is between 5MHz and 6 MHz typically, the embodiment down-converts the clock signal CLKS in the image signal from the host system to obtain a scan timing signal SS of a suitable frequency without utilizing an oscillator as a conventional digitizer module board. Thus, in this embodiment, the multifunctional digitizer module board440and the LCD panel420are coupled to the host system600via a single interface, and the microcontroller of the multifunctional digitizer module board440is integrated to that of the display panel. In this embodiment, timing controller322comprises a frequency divider329to convert the clock signal of the image signal to the scan timing signal SS with a frequency suitable for the multifunctional digitizer module board440.

The LCD panel420is coupled to the control unit482to display images according to the analog signals from the DAC328. The display panel can also be an organic light-emitting diode (OLED) display panel, or a field emission display (FED) panel.

The multifunctional digitizer module board440is typically used for cursor control applications, such as selection to display icons and menu items, creating or tracing drawings or blueprints, or for character or handwriting recognition. In this embodiment, the multifunctional digitizer module board440is coupled to the host system600via the same interface480and executes a scan operation to generate position data PD in response to the scan timing signal SS. The multifunctional digitizer module board440comprises a digitizer sensor array342, a selection circuit346, and an amplifier348. In some examples, the digitizer sensor array342, the selection circuit346and the amplifier348are formed on the flexible digitizer sensor board442shown inFIG. 3. Alternately, the selection circuit346and the amplifier348can be integrated to the control unit482(not shown). For example, the multifunction digitizer module board can be an electromagnetic sensing digitizer module board, in which electromagnetic signals are transmitted from the position pointer344and sensed by the sensor array342.

The digitizer sensor array342, for example, comprises metal coil grids in both X and Y orientations, sensing the position of the position pointer344. The position pointer344transmits signals to the digitizer sensor array, and the selection circuit346performs the scan operation of the coils in the sensor array342according to the scan timing signal from the control unit482, such that signals induced in the sensor array342are sent to the amplifier348, and the amplifier348amplifies the induced signals in the sensor array342.

The amplified signals from the amplifier348are output to the ADC324and converted to position data PD to the control unit. The control unit322receives the position data PD relative to the pointer344and determines the corresponding coordinate data CD of the pointer344accordingly. The corresponding coordinate data CD of the pointer344is then output to the host system600via the interface480. For example, the control unit482can be a single chip integrated by the timing controller322, the ADC324, the voltage adjustment circuit326, and the DAC328. The control unit320can also be a chip on glass (COG) of the display panel330or mounted on a flexible printed circuit board (FPC) of the display panel420.

FIG. 6shows an embodiment of a timing controller. The timing controller322comprises a processing device331, a frequency divider (FD)329, a timing generator332, a data latch333, a register334, and a receiving and decoding device335, and receives the image signal IS and bus control signal BCS from the host system600via the interface480.

The processing device331is coupled to the ADC324to receive the position data PD and calculate the corresponding coordinate data CD for output to the host system600via the interface480. The host system600receives the coordinate data CD and converts to image signal to display on the display panel. The frequency divider329converts 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 multifunctional digitizer module board440.

The timing generator332also receives the clock signal CLKS to provide reference timing signals RTS for the display panel420. The image data ID in the image signal IS from the host system600is temporarily stored by the data latch333and the register334and output to the DAC328to drive the display panel420. The receiving and decoding device335receives the bus control signal BCS from the host system600to generate control data controlling operations of the DAC328, the ADC324and the selection circuit346.

Thus, some embodiments of the invention can use a single interface and integrate microcontroller126, ADC125for the multifunctional digitizer module board120, and timing controller127, the voltage adjustment circuit132and the DAC131for the LCD module110show inFIG. 2into that of the display panel, such that cost, thickness and weight of the display system are be reduced.

FIG. 7schematically shows an electronic device500deploying display system400disclosed. The display system400can 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 device500may be a portable device such as a PDA, notebook computer, tablet computer, cellular phone, or a display monitor device, etc. Generally, the electronic device500includes a housing510, the display system400shown inFIG. 4, a DC/DC converter520, etc. Further, the DC/DC converter520is operatively coupled to the display system400and provides an output voltage powering the display system400to display images.