Patent Publication Number: US-2019197929-A1

Title: Driving apparatus of display panel and operation method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of U.S. provisional application Ser. No. 62/610,291, filed on Dec. 26, 2017. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
    
    
     BACKGROUND 
     Field of the Invention 
     The invention relates to a display apparatus and more particularly to a driving apparatus of a display panel and an operating method thereof. 
     Description of Related Art 
     Generally, during a production process of display apparatuses, a manufacturer needs to adjust and calibrate various display parameters of the display apparatuses. For example, the manufacturer needs to adjust and calibrate gamma curves and/or color temperatures of the display apparatuses during the production process. Before adjusting and calibrating the gamma curves and/or the color temperatures, the manufacturer needs to measure brightness values and/or color coordinate values of specific test images (test patterns). A test system (test platfonn) has to transmit the specific test images (test frame data) to a display driving integrated circuit through a video interface of the display driving integrated circuit, such that the display driving integrated circuit may drive a flat-panel display module to display the aforementioned specific test images. Generally, the video interface may be a low-voltage differential signal (LVDS) interface. During a period in which the flat-panel display module displays the specific test images, the manufacturer may use an optical instrument to measure the brightness values and the color coordinate values of the images displayed by the flat-panel display module to serve as databases required for the gamma curves and the color temperatures. With the databases, the test system may calculate a red gamma curve, a green gamma curve, a blue gamma curve, color temperatures and/or other display parameters of the flat-panel display module. 
     After calculating the display parameters, the test system (the test platform) may burn the display parameters into a one-time programming (OTP) element, an electrically erasable programmable read only memory (EEPROM) or any other memory in the display driving integrated circuit through a command interface of the display driving integrated circuit. Generally, the command interface may be a serial peripheral interface (SPI) or an inter-integrated circuit (I 2 C). 
     Thus, the test system (the test platform) has to be capable of providing the specific test images. In order to provide the specific test images (the test frame data), the test system (the test platfoiin) has to be designed in a more complicated manner. However, for reducing testing cost and improving testing efficiency, simplifying the design of the test system is an effective approach. When the test system no longer has to provide the specific test images (the test frame data) to the display driving integrated circuit, the testing cost may be reduced. 
     SUMMARY 
     The invention provides a driving apparatus of a display panel and an operating method thereof which are capable of self-generating test frame data representing a test pattern. 
     According to an embodiment of the invention, a driving apparatus of a display panel for generating a plurality of test frame data in an optical measurement is provided. The driving apparatus includes a command interface circuit, a video interface circuit, a built-in self test (BIST) circuit, a multiplex circuit and a driving circuit. The command interface circuit is configured to receive a test command including a grayscale parameter. The video interface circuit is configured to receive video frame data. The BIST circuit is coupled to the command interface circuit to receive the test command. The BIST circuit generates test frame data representing a test pattern according to the test command and sets a grayscale of the test pattern according to the grayscale parameter included in the test command. The multiplexer circuit is coupled to the BIST circuit to receive the test frame data. The multiplexer circuit is coupled to the video interface circuit to receive the video frame data. The multiplex circuit is configured to select to output the test frame data in a test mode and select to output the video frame data in a normal operation mode. The driving circuit is coupled to an output terminal of the multiplex circuit. The driving circuit is configured to drive the display panel to display an image according to the test frame data or the video frame data output from the output terminal of the multiplex circuit. 
     According to an embodiment of the invention, a driving apparatus of a display panel for generating a plurality of test frame data in an optical measurement is provided. The driving apparatus includes a command interface circuit, a BIST circuit and a driving circuit. The command interface circuit is configured to receive a test command including a grayscale parameter. The BIST circuit is coupled to the command interface circuit to receive the test command. The BIST circuit generates test frame data representing a test pattern according to the test command and sets a grayscale of the test pattern according to the grayscale parameter included in the test command. The driving circuit is configured to drive the display panel to display the test frame data. 
     According to an embodiment of the invention, an operating method of a driving apparatus of a display panel is provided. The driving apparatus is configured to generate a plurality of test frame data in an optical measurement. The operating method includes: receiving a test command including a grayscale parameter by a command interface circuit; receiving video frame data by a video interface circuit; generating test frame data representing a test pattern according to the test command and setting a grayscale of the test pattern according to the grayscale parameter included in the test command by a BIST circuit; selecting to output the test frame data in a test mode by a multiplex circuit; selecting to output the video frame data in a normal operation mode by the multiplexer circuit; and driving the display panel to display an image according to the test frame data or the video frame data output by the multiplex circuit by a driving circuit. 
     According to an embodiment of the invention, an operating method of a driving apparatus of a display panel is provided. The driving apparatus is configured to generate a plurality of test frame data in an optical measurement. The operating method includes: receiving a test command including a grayscale parameter by a command interface circuit; generating test frame data representing a test pattern according to the test command and setting a grayscale of the test pattern according to the grayscale parameter included in the test command by a BIST circuit; and driving the display panel to display the test frame data by a driving circuit. 
     To sum up, the driving apparatus of the display panel and the operating method thereof provided by the embodiments of the invention can generate the test frame data representing the test pattern by using the BIST circuit. The grayscale of the test pattern can be dynamically set according to the grayscale parameter included in the test command from an external apparatus (e.g., a test system). Thus, the test frame data generated by the BIST circuit can be applied to adjust and calibrate display parameters (e.g., gamma curves and/or color temperatures). Because the driving apparatus can self-generate the test frame data representing the test pattern, the external apparatus (e.g., the test system) is not required to transmit the test frame data required for the measurement with a video interface. 
     To make the above features and advantages of the invention more comprehensible, embodiments accompanied with drawings are described in detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a schematic circuit block diagram illustrating a driving apparatus of a display panel according to an embodiment of the invention. 
         FIG. 2  is a flowchart illustrating an operating method of a driving apparatus of a display panel according to an embodiment of the invention. 
         FIG. 3  is a schematic circuit block diagram illustrating a driving apparatus of a display panel according to another embodiment of the invention. 
         FIG. 4  is a flowchart illustrating an operating method of a driving apparatus of a display panel according to another embodiment of the invention. 
         FIG. 5  is a schematic circuit block diagram illustrating the built-in self test (BIST) circuit depicted in  FIG. 1  and/or  FIG. 3  according to an embodiment of the invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The term “couple (or connect)” herein (including the claims) are used broadly and encompass direct and indirect connection or coupling means. For example, if the disclosure describes a first apparatus being coupled (or connected) to a second apparatus, then it should be interpreted that the first apparatus can be directly connected to the second apparatus, or the first apparatus can be indirectly connected to the second apparatus through other devices or by a certain coupling means. Moreover, elements/components/steps with same reference numerals represent same or similar parts in the drawings and embodiments. Elements/components/notations with the same reference numerals in different embodiments may be referenced to the related description. 
       FIG. 1  is a schematic circuit block diagram illustrating a driving apparatus  100  of a display panel according to an embodiment of the invention. The driving apparatus  100  may generate a plurality of test frame data in an optical measurement. The driving apparatus  100  may drive a display panel  11  to display test frame data (e.g., a test pattern  12  which is also an image). The driving apparatus can be a display driver chip. Based on a design requirement, the display panel  11  may be a liquid crystal display panel, a light emitting diode panel, or any other flat-panel display module. During a period in which the display panel  11  displays the test pattern  12 , an optical measurement device  13  may optically measure the test pattern  12  displayed by the display panel  11  and provide an optical measurement result to a test system (a test platform)  10 . For instance, the optical measurement device  13  may measure brightness values and/or color coordinate values of images displayed by the display panel  11 , and the test system  10  may serve the brightness values and/or the color coordinate values provided by the optical measurement device  13  as databases required for adjusting gamma curves and color temperatures of the driving apparatus. 
     More specifically, with these databases, the test system  10  may calculate a plurality of display setting parameters, for example, a red gamma curve, a green gamma curve, a blue gamma curve, a color temperature and/or other display setting parameters. The display setting parameters may include information associated with the test frame data. After calculating the display setting parameters, the test system  10  may store the display setting parameters into a memory (not shown) of the driving apparatus  100  (e.g., an one-time programming (OTP) circuit, an electrically erasable programmable read only memory (EEPROM) or any other memory) through a command interface circuit of the driving apparatus  100 . 
     Based on a design requirement, in some other embodiments, the driving apparatus  100  may be coupled to a storage device (not shown). After calculating the display setting parameters, the test system  10  may store the display setting parameters in the storage device (not shown) through the driving apparatus  100 . The driving apparatus  100  may drive the display panel  11  to display images according to the display setting parameters stored in the storage device. 
     In the embodiment illustrated in  FIG. 1 , the driving apparatus  100  can include at least a command interface circuit  110 , a built-in self test (BIST) circuit  120  and a driving circuit  130 . The driving circuit  130  may drive the display panel  11  to display an image. The implementation manner of the driving circuit  130  is not limited in the invention. For instance, the driving circuit  130  may include at least a conventional source driving circuit or another driving circuit. The command interface circuit  110  may receive a test command  10   a  including a grayscale parameter from the test system  10 . The command interface circuit  110  may transmit the test command  10   a  to the BIST circuit  120 . Based on a design requirement, the command interface circuit  110  may be a conventional command interface circuit or any other command interface circuit. For instance, the command interface circuit  110  may be a serial peripheral interface (SPI) circuit, an inter-integrated circuit (I 2 C) interface circuit or any other command interface circuit. 
       FIG. 2  is a flowchart illustrating an operating method of a driving apparatus of a display panel according to an embodiment of the invention. Referring to  FIG. 1  and  FIG. 2 , the BIST circuit  120  is coupled to the command interface circuit  110  to receive a test command (step S 210 ). In step S 220 , the BIST circuit  120  may generate test frame data representing the test pattern  12  according to the test command  10   a . In step S 220 , the BIST circuit  120  may further set a grayscale of the test pattern  12  according to a grayscale parameter included in the test command  10   a . In step S 230 , the driving apparatus  130  may drive the display panel  11  to display the test frame data (e.g., the test pattern  12  which is also an image). 
     A data structure of the test command  10   a  may be determined based on a design requirement. For instance, in some embodiments, the grayscale parameter included in the test command  10   a  includes a plurality of bits, and the bits are configured to set a grayscale for one of a red test pattern, a green test pattern and a blue test pattern. In some other embodiments, the grayscale parameter included in the test command  10   a  includes a plurality of first bits, a plurality of second bits and a plurality of third bits. The first bits are configured to set a red grayscale for a white test pattern, the second bits are configured to set a green grayscale for the white test pattern, and the third bits are configured to set a blue grayscale for the white test pattern. Thus, the BIST circuit  120  may set the grayscale of the test pattern  12  according to the grayscale parameter included in the test command  10   a.    
     The driving apparatus  100  and the operating method thereof illustrated in FIG. 1  and  FIG. 2  may generate the test frame data representing the test pattern  12  by using the BIST circuit  120 . The grayscale of the test pattern  12  may be dynamically set according to the grayscale parameter included in the test command  10   a  of the test system  10 . Thus, the test frame data generated by the BIST circuit  120  may be applied to adjust and calibrate display parameters (e.g., gamma curves and/or color temperatures). Because the driving apparatus  100  is capable of self-generating the test frame data representing the test pattern  12 , the test system  10  is not required to transmit test frame data required for the measurement with a video interface. 
       FIG. 3  is a schematic circuit block diagram illustrating a driving apparatus  300  of a display panel according to another embodiment of the invention. The driving apparatus  300  may generate a plurality of test frame data in an optical measurement. A test system  10 , a test command  10   a , the driving apparatus  300 , a display panel  11 , a test pattern  12  and an optical measurement device  13  may be inferred with reference to the test system  10 , the test command  10   a , the driving apparatus  100 , the display panel  11 , the test pattern  12  and the optical measurement device  13  of the embodiment illustrated in  FIG. 1  and thus, will not be repeatedly described. In a scenario illustrated in  FIG. 3 , it shows that the driving apparatus  300  is operated in a test mode, i.e., the driving apparatus  300  is electrically connected to the test system  10 . After a test is completed, the driving apparatus  300  may be disconnected from the test system  10 , and then, the driving apparatus  300  and the display panel  11  are installed in an electronic product. Namely, in a normal operation mode, the driving apparatus  300  is electrically connected to a control circuit (not shown, for example, a processor) in the electronic product. 
     In the embodiment illustrated in  FIG. 3 , the driving apparatus  300  includes a command interface circuit  110 , a BIST circuit  120 , a drive unit  130 , a video interface circuit  310  and a multiplexer circuit  320 . The command interface circuit  110 , the BIST circuit  120  and the driving circuit  130  illustrated in  FIG. 3  may be inferred with reference to the description related to the embodiment illustrated in  FIG. 1  and thus, will not be repeatedly described. In the test mode, the video interface circuit  310  may not be connected to any other external apparatus/circuit. In the normal operation mode, the video interface circuit  310  may be electrically connected to the control circuit (not shown, for example, the processor) in the electronic product, so as to receive video frame data. 
       FIG. 4  is a flowchart illustrating an operating method of a driving apparatus of a display panel according to another embodiment of the invention. Referring to  FIG. 3  and  FIG. 4 , the command interface circuit  110  receives the test command  10   a  in step S 410 . In step S 420 , the BIST circuit  120  generates the test frame data representing the test pattern  12  according to the test command  10   a  and sets the grayscale of the test pattern  12  according to the test command  10   a . In step S 430 , the video interface circuit  310  receives the video frame data. The operation mode of the driving apparatus  300  may be determined in step S 440 . When the operation mode of the driving apparatus  300  is the test mode, step S 450  is performed. When the operation mode of the driving apparatus  300  is the normal operation mode, step S 460  is performed. 
     A first input terminal of the multiplexer circuit  320  is coupled to the BIST circuit  120  to receive the test frame data. A second input terminal of the multiplexer circuit  320  is coupled to the video interface circuit  310  to receive the video frame data. An output terminal of the multiplexer circuit  320  is coupled to an input terminal of the driving circuit  130 . In the test mode, the multiplexer circuit  320  may select to output the test frame data provided by the BIST circuit  120  to the driving circuit  130  (step S 450 ). In the normal operation mode, the multiplexer circuit  320  may select to output the video frame data provided by the video interface circuit  310  to the driving circuit  130  (step S 460 ). 
     The driving circuit  130  can be coupled to the output terminal of the multiplex circuit  320 . In step S 470 , the driving circuit  130  may drive the display panel  11  to display an image according to the test frame data or the video frame data output from the output terminal of the multiplex circuit  320 . In the test mode, the image is the test pattern  12 . In the normal operation mode, the image is a normal image. 
       FIG. 5  is a schematic circuit block diagram illustrating the BIST circuit  120  depicted in  FIG. 1  and/or  FIG. 3  according to an embodiment of the invention. In the embodiment illustrated in  FIG. 5 , the BIST circuit  120  includes a resolution register  121 , a test pattern register  122 , a synchronization signal generation circuit  123  and a test pattern generation circuit  124 . It is assumed here that the test command  10   a  of the test system  10  has at least one resolution parameter and at least one pattern parameter. The pattern parameter includes the grayscale parameter. The resolution parameter from the command interface circuit  110  may be stored in the resolution register  121 , and the pattern parameter from the command interface circuit  110  may be stored in the test pattern register  122 . 
     The synchronization signal generation circuit  123  can be coupled to the resolution register  121  to read the resolution parameter. The synchronization signal generation circuit  123  may correspondingly generate a vertical synchronization signal Vsync and a horizontal synchronization signal Hsync according to the resolution parameter. The test pattern generation circuit  124  can be coupled to the synchronization signal generation circuit  123  to receive the vertical synchronization signal Vsync and the horizontal synchronization signal Hsync. 
     In the embodiment illustrated in  FIG. 5 , the synchronization signal generation circuit  123  includes an oscillation circuit  501 , a vertical counting circuit  502  and a horizontal counting circuit  503 . The oscillation circuit  501  may generate a clock signal CLK. The vertical counting circuit  502  and the horizontal counting circuit  503  are coupled to the resolution register  121  to read the resolution parameter. The vertical counting circuit  502  and the horizontal counting circuit  503  are coupled to the oscillation circuit  501  to receive the clock signal CLK. The vertical counting circuit  502  may count the clock signal CLK to obtain a first count result. The horizontal counting circuit  503  may count the clock signal CLK to obtain a second count result. The horizontal counting circuit  503  may correspondingly generate the horizontal synchronization signal Hsync to the test pattern generation circuit  124  according to a relationship between the second count result and the resolution parameter. The vertical counting circuit  502  is further coupled to the horizontal counting circuit  503  to receive the horizontal synchronization signal Hsync. The vertical counting circuit  502  may correspondingly generate the vertical synchronization signal Vsync to the test pattern generation circuit  124  according to a relationship among the horizontal synchronization signal Hsync, the second count result and the resolution parameter. 
     The implementation manners of the oscillation circuit  501 , the vertical counting circuit  502  and the horizontal counting circuit  503  are not limited in the present embodiment. For instance, the oscillation circuit  501  may include a conventional oscillator or any other oscillation circuit/element, the vertical counting circuit  502  may include a conventional vertical signal generator or any other vertical counting circuit/element, and the horizontal counting circuit  503  may include a conventional horizontal signal generator or any other horizontal counting circuit/element. 
     The test pattern generation circuit  124  can be coupled to the test pattern register  122  to read the pattern parameter (including the grayscale parameter). The test pattern generation circuit  124  may generate the test frame data according to the pattern parameter and set the grayscale of the test pattern  12  according to the grayscale parameter. The test pattern generation circuit  124  may output the test frame data to the driving circuit  130  illustrated in  FIG. 1  or may output the test frame data to the multiplexer circuit  320  illustrated in  FIG. 3 . The specific content corresponding to the test pattern  12  of the test frame data may be determined based on a design requirement. For example, the test pattern  12  may be a one-color frame (e.g., a white frame, a red frame, a green frame or a blue frame), and the test pattern generation circuit  124  may set the grayscale of the one-color frame according to the grayscale parameter of the test pattern register  122 . 
     The blocks of the BIST circuit  120 , the driving circuit  130  and/or the test pattern generation circuit  124  may be implemented not only by a logic circuit (i.e., hardware) on an integrated circuit, but also by software through a central processing unit (CPU). In the latter case, related functions of the BIST circuit  120 , the driving circuit  130  and/or the test pattern generation circuit  124  may be implemented as programming codes of software (i.e., programs). For example, the BIST circuit  120 , the driving circuit  130  and/or the test pattern generation circuit  124  may be implemented by using general programming languages (e.g., C or C++) or other suitable programming languages. The aforementioned software (i.e., the programs) may be accessed by a computer (or the CPU) and recorded/stored in a read only memory (ROM), a storage device (or referred to as a recording medium) and/or a random access memory (RAM). Additionally, the programs may be accessed from the recording medium and executed by the computer (or the CPU) to accomplish the related functions. As for the recording medium, a non-transitory computer readable medium, such as a tape, a disk, a card, a semiconductor memory or a programmable logic circuit, may be used. In addition, the programs may be provided to the computer (or the CPU) through any transmission medium (e.g., a communication network or radio waves). The communication network is, for example, the Internet, wired communication, wireless communication or other communication media. 
     In different application scenarios, related functions of the BIST circuit  120 , the driving circuit  130  and/or the test pattern generation circuit  124  may be implemented in a form of firmware or hardware by utilizing general programming languages (e.g., C or C++), hardware description languages (e.g., Verilog HDL or VHDL) or other suitable programming languages. In terms of the hardware implementation, one or more controllers, micro-controllers, application-specific integrated circuits (ASICs), digital signal processors (DSPs), field programmable gate arrays (FPGAs) and/or other various logic blocks, modules and circuits in other processing units may be employed to implement or execute the aforementioned functions of the embodiments of the invention. Moreover, the device and the method of the invention may be implemented by a combination of hardware and software. 
     Based on the above, the driving apparatus of the display panel and the operating method thereof provided by the embodiments of the invention can generate the test frame data representing the test pattern by using the BIST circuit. The grayscale of the test pattern can be dynamically set according to the grayscale parameter included in the test command of the external apparatus (e.g., the test system). Thus, the test frame data generated by the BIST circuit can be applied to adjust and calibrate the display parameters (e.g., the gamma curves and/or the color temperatures). Because the driving apparatus can self-generate the test frame data representing the test pattern. There is no need for configuring an external apparatus (e.g., the test system) to transmit the test frame data required by the measurement with a video interface between the external apparatus and the driving apparatus. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.