Patent Publication Number: US-2023154421-A1

Title: Backlight control device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This non-provisional application claims priority under 35 U.S.C. § 119(a) to Patent Application No. 110142460 filed in Taiwan, R.O.C. on Nov. 15, 2021, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND 
     Technical Field 
     The present invention relates to a control device of a backlight panel. 
     Related Art 
     According to various application needs, a flat-panel display often needs to use a transmission interface to transmit backlight data to a backlight module. For example, the backlight data is transmitted to the backlight module through the transmission interface, to control the brightness of a backlight source, or a plurality of backlight sources for partitioned backlighting are separately controlled through the transmission interface. Conventional backlight data transmission interfaces adopt transmission protocols such as serial peripheral interface (SPI), inter-integrated circuit (I 2 C), RS-232, transistor-transistor logic (TTL), or the like. These transmission interfaces provide point-to-point signal transmission between a panel control chip and single or a plurality of backlight sources. Taking the SPI as an example, four wires are needed for single-point control, which are respectively serial clock (SCLK), master output slave input (MOSI), master input slave output (MISO), and slave select (SS). 
     With the development of the market trend, the demand for large-size and high-resolution displays is increasing. To provide a large-size and high-resolution display, one resolution is to provide a display with a large amount of partition backlight sources. However, under a conventional transmission architecture, the display needs to use a large amount of wires to control the large amount of backlight sources. 
     When the display uses a large amount of wires, at least the following problems are caused: (1) The cost for the wiring increases; (2) The quantity of I/O of the transmitting end chip or receiving end chip increases, causing the production cost to increase; (3) The space occupied by the wiring increases; (4) The complexity of the system needs to be increased, to resolve the problem of transmission delay skew caused by inconsistent wiring distances; and (5) Mutual interference of electromagnetic noise is likely to happen among the large amount of wires. To reduce the electromagnetic interference, the transmission speed of the display using the conventional transmission interfaces cannot be excessively high. 
     SUMMARY 
     In view of this, according to some embodiments, a device adapted for controlling a plurality of backlight sources is provided. The device comprises a timing control circuitry and a local-dimming control circuitry. The timing control circuitry is configured to generate a transmission packet according to a first customized content specification, where the transmission packet includes control information and brightness information. The timing control circuitry includes a first differential circuit, where the first differential circuit is configured to transmit the transmission packet according to a differential voltage level. The local-dimming control circuitry includes a first receiving circuit, where the first receiving circuit is electrically coupled to the first differential circuit. The first receiving circuit is configured to receive the transmission packet. The local-dimming control circuitry is configured to transmit a light source control signal according to the control information and the brightness information. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic block diagram of a backlight control device and backlight sources according to some embodiments; 
         FIG.  2    is a schematic diagram of a timing control module and a local-dimming control module according to a first embodiment; 
         FIG.  3 A  is a schematic diagram of a transmission packet according to some embodiments; 
         FIG.  3 B  is a schematic diagram of a transmission packet according to some other embodiments; 
         FIG.  4    is a schematic diagram of an operation status of a backlight control device according to some embodiments; 
         FIG.  5    is a schematic diagram of a timing control module and a local-dimming control module according to a second embodiment; 
         FIG.  6    is a schematic diagram of a differential signal according to some embodiments; 
         FIG.  7    is a schematic diagram of a timing control module and a local-dimming control module according to a third embodiment; 
         FIG.  8    is a schematic block diagram of a backlight control device and a liquid crystal panel according to some embodiments; 
         FIG.  9 A  is a schematic diagram of a backlight control device, a backlight panel, and a liquid crystal panel according to some embodiments; and 
         FIG.  9 B  is a schematic diagram of a backlight control device, a backlight panel, and a liquid crystal panel according to some other embodiments. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    is a schematic block diagram of a backlight control device and backlight sources according to some embodiments. Referring to  FIG.  1   , according to some embodiments, a backlight control device  200  controls a plurality of backlight sources  101 . The backlight source  101  may refer to a light source that emit light actively, such as but not limited to an incandescent light bulb, a light-emitting diode, a fluorescent lamp, or a light-emitting panel. The backlight source  101  may be a direct-lit backlight source directly disposed on the back of a liquid crystal panel to provide lighting, or may be an edge-lit light source disposed on a side of the liquid crystal panel to provide lighting through a reflector or a light guide plate. According to some embodiments, the plurality of backlight sources  101  are arranged in an array, to provide partitioned backlighting. 
     The backlight control device  200  includes a timing control circuitry  201  and a local-dimming control circuitry  203 . According to some embodiments, the timing control circuitry  201  includes a timing controller (TCON)  2015 . The timing control circuitry  201  receives image data D, and generates one or more transmission packets used for controlling the backlight sources  101  according to a first customized content specification. The transmission packet includes control information and brightness information, which are described in detail below. 
     The timing control circuitry  201  includes a first differential circuit  2011 , where the first differential circuit  2011  transmits the transmission packet according to a differential voltage level. According to some embodiments, a configuration of the differential circuit is based on circuit logic of a differential architecture such as low voltage differential signaling (LVDS), emitter coupled logic (ECL), positive emitter coupled logic (PECL), or current mode logic (CML). 
     According to some embodiments, the local-dimming control circuitry  203  includes a backlight controller (BCON)  2035 . For example, the BCON  2035  is based on pulse-width modulation (PWM) dimming or analog dimming. The local-dimming control circuitry  203  receives the transmission packet, and generates a light source control signal according to the control information and the brightness information included in the transmission packet, to control the backlight sources  101 . The local-dimming control circuitry  203  includes a first receiving circuit  2031  electrically coupled to the first differential circuit  2011 . According to some embodiments, the first receiving circuit  2031  is a voltage detection circuit with a high input impedance, such as an operational amplifier or a buffer. 
     According to some embodiments, the timing control circuitry  201  includes a digital-to-analog converter, where the digital-to-analog converter converts the transmission packet into the differential voltage level and transmits the differential voltage level to the first receiving circuit  2031  of the local-dimming control circuitry  203  through the first differential circuit  2011 . Correspondingly, the local-dimming control circuitry  203  includes an analog-to-digital converter, where the analog-to-digital converter is configured to convert the differential voltage level back into the transmission packet. 
       FIG.  2    is a schematic diagram of a timing control circuitry and a local-dimming control circuitry according to a first embodiment. Referring to  FIG.  2   , according to some embodiments, the timing control circuitry  201  includes the TCON  2015  and the first differential circuit  2011 ; and the local-dimming control circuitry  203  includes the first receiving circuit  2031  and the BCON  2035 . The first differential circuit  2011  of the timing control circuitry  201  generates a differential signal, to transmit the transmission packet. The first receiving circuit  2031  of the local-dimming control circuitry  203  is electrically coupled to the first differential circuit  2011  through a pair of transmission lines, to receive the differential signal. The differential signal may be a voltage signal or a current signal, which causes the differential voltage level. The differential voltage level may be classified by a standard for distinguishing a high logic level or a low logic level. For example, the first differential circuit  2011  is a current source configured to provide a current signal with a differential voltage level of plus or minus 3.5 mA. The current signal flows through a resistor R that is bridged to the transmission lines and has a resistance of 100 Ω, and generates a voltage level of plus or minus 350 mV between both ends of the resistor R. The first receiving circuit  2031  measures the foregoing voltage level. The voltage level of plus 350 mV is classified as a high logic level, and the voltage level of minus 350 mV is classified as a low logic level. 
     The timing control circuitry  201  generates the transmission packet according to the first customized content specification. According to some embodiments, the first customized content specification is used for compiling the brightness information corresponding to a plurality of backlight sources  101  into the transmission packet, so that the transmission packet is adapted to be transmitted through the first differential circuit  2011 . According to some embodiments, the transmission packet includes a start byte, a data sequence, and an end byte.  FIG.  3 A  is a schematic diagram of a transmission packet according to some embodiments. Taking a transmission packet P 0  shown in  FIG.  3 A  as an example, the transmission packet P 0  includes fields of a start byte from Head byte[0] to Head byte[n], fields of a data sequence from DATA0[7:0] to DATA10367[11:4], and fields of an end byte from Tailor byte[0] to Tailor byte[1]. The first differential circuit  2011  transmits field contents of the transmission packet bit by bit. 
     According to some embodiments, the start byte marks the beginning of data. When the first receiving circuit  2031  receives the start byte, the local-dimming control circuitry  203  determines that a new transmission packet is received. The data sequence stores the brightness information used for controlling each of the backlight sources  101 . For example, the transmission packet P 0  according to an embodiment shown in  FIG.  3 A  is used for controlling 10368 backlight sources  101 , and each of the backlight sources  101  corresponds to brightness information of 12 bits. Therefore, DATA0[7:0] (8 bits) of the first field and DATAO[11:8] (4 bits) of the second field of the data sequence correspond to a No. 0 backlight source  101 ; and DATA1[3:0] (4 bits) of the second field of the data sequence and DATA1[11:4] (8 bits) of the third field of the data sequence correspond to a No. 1 backlight source  101 , and so on. The brightness information corresponding to each of the backlight sources  101  may not be of 8 bits (for example, 12 bits in the embodiment shown in  FIG.  3 A ). Therefore, according to some embodiments, the start byte includes the control information. The control information may be used for informing the local-dimming control circuitry  203  of a quantity of bits of the brightness information corresponding to each of the backlight sources  101 . According to some embodiments, the end byte marks the end of data, and when the first receiving circuit  2031  receives the end byte, the local-dimming control circuitry  203  determines that the received transmission packet ends. 
       FIG.  3 B  is a schematic diagram of a transmission packet according to some other embodiments. Referring to  FIG.  3 A  and  FIG.  3 B  together, in the embodiment shown in  FIG.  3 A , the single transmission packet P 0  stores the brightness information corresponding to a total of 10368 backlight sources  101 . According to some embodiments, the transmission packet P 0  is transmitted by a set of a first differential circuit  2011  and a first receiving circuit  2031 . In an embodiment shown in  FIG.  3 B , two transmission packets including a transmission packet P 0  and a transmission packet P 1  store the brightness information corresponding to the total of 10368 backlight sources  101 . According to some embodiments, the transmission packet P 0  and the transmission packet P 1  are separately transmitted by two sets of a first differential circuit  2011  and a first receiving circuit  2031 , thereby improving the transmission speed. 
     According to some embodiments, the brightness information corresponding to each of the backlight sources  101  is compiled into one or more transmission packets according to the first customized content specification. For example, in the embodiment shown in  FIG.  3 A , first 12 bits of the data sequence of the transmission packet P 0  correspond to the No. 0 backlight source  101 , and by analogy to No. 1, No. 2, ..., and No. 10367 of the backlight sources  101 . Therefore, the brightness information stored in the data sequence corresponds to a number sequence of the backlight sources  101  in sequence. In the embodiment shown in  FIG.  3 B , first 12 bits of a data sequence of the transmission packet P 0  correspond to the No. 0 backlight source  101 , and by analogy to No. 1, No. 4, No. 5, ..., and No. 10365 of the backlight sources  101 ; and first 12 bits of a data sequence of the transmission packet P 1  correspond to the No. 2 backlight source  101 , and by analogy to No. 3, No. 6, No. 7, ..., and No. 10367 of the backlight sources  101 . Therefore, all of the brightness information is alternately stored in the two transmission packets with every two pieces of brightness information as a cycle. According to some embodiments, to resolve the problem of data correspondence of a plurality of transmission packets in transmission, the start byte includes the control information. The control information enables the local-dimming control circuitry  203  to identify the brightness information stored in each of the transmission packets, and each of the backlight sources  101  corresponding to the brightness information. 
     As described above, according to some embodiments, a transmission interface between the timing control circuitry  201  and the local-dimming control circuitry  203  adopts a differential configuration. According to some embodiments, the backlight control device  200  adopts a sequence transmission solution of quick data transmission instead of a parallel transmission solution of synchronous data transmission adopted by a conventional transmission interface, thereby resolving problems derived from the large amount of wires used by a conventional display. In this way, the backlight control device  200  allows control over a large amount of backlight sources  101 . For example, a conventional interface needs 8 sets of SPIs and 32 wires in total to transmit parallel data of 8 bits. For a data volume of the 10368 backlight sources  101  and the brightness information of 12 bits, and considering the limitation of each frame within 1 ms (with a vertical blanking time of a scanning liquid crystal panel &lt; 1 ms), a transmission speed of a single SPI needs to be 10368 ∗ 12 bit / 8 port / 1 ms = 15.552 Mbps, which is still lower than a transmission upper limit of 20 Mbps of the SPI. By comparison, a differential configuration needs a single set of a differential transmission interface and 2 wires in total to transmit sequence data. Taking an LVDS transmission interface as an example, for transmission of the data volume of the 10368 backlight sources  101  and the brightness information of 12 bits, and considering the limitation of each frame within 1 ms, a transmission speed of a single LVDS needs to be 10368 ∗ 12 bit / 1 pair / 1 ms = 124.416 Mbps, which is far lower than a transmission upper limit of 600 Mbps of the LVDS. According to some embodiments, the timing control circuitry  201  generates the transmission packet according to the first customized content specification, and the local-dimming control circuitry  203  parses the received transmission packet according to the first customized content specification, and further determines the correspondence between the brightness information of the transmission packet and the backlight sources  101 . 
       FIG.  4    is a schematic diagram of an operation status of a backlight control device according to some embodiments. Referring to  FIG.  4   , according to some embodiments, the backlight control device  200  includes the timing control circuitry  201 , the local-dimming control circuitry  203 , and a buffer memory  204 . The buffer memory  204  is electrically coupled to the local-dimming control circuitry  203  and is configured to temporarily store the transmission packet. According to some embodiments, the timing control circuitry  201  generates transmission packets frame by frame, and each of the transmission packets includes the brightness information of all of the backlight sources  101 . After being transmitted to the local-dimming control circuitry  203  by the timing control circuitry  201 , the transmission packets are forwarded by the local-dimming control circuitry  203  to and temporarily stored in the buffer memory  204 . For example, in an embodiment shown in  FIG.  4   , a transmission packet P 0 , a transmission packet P 1 , a transmission packet P 2 , and a transmission packet P 3  respectively store brightness information of four frames F. According to some embodiments, the timing control circuitry  201  generates a plurality of transmission packets frame F by frame F. The plurality of transmission packets are transmitted to and temporarily stored in the buffer memory  204 . For example, in the embodiment shown in  FIG.  4   , the transmission packet P 0 , the transmission packet P 1 , the transmission packet P 2 , and the transmission packet P 3  store brightness information respectively corresponding to four sets of backlight sources  101  within a range of one frame F. 
     According to some embodiments, the local-dimming control circuitry  203  of the backlight control device  200  transmits the light source control signal to the plurality of backlight sources  101  one by one in a scanning manner. For example, referring to  FIG.  4   , the local-dimming control circuitry  203  adjusts the backlight sources  101  one by one from left to right according to a scanning axis X, moves to a next row according to a scanning axis Y when moving to the rightmost, and adjusts the backlight sources  101  one by one again according to the scanning axis X. Therefore, when scanning to a specific backlight source  101 , the local-dimming control circuitry  203  needs to adjust the specific backlight source  101  according to brightness information corresponding to the specific backlight source  101 . According to some embodiments, before the local-dimming control circuitry  203  scans to the specific backlight source  101 , the local-dimming control circuitry  203  reads the brightness information corresponding to the specific backlight source  101  from the buffer memory  204 . For example, before scanning a first row of the backlight sources  101 , the local-dimming control circuitry  203  reads brightness information corresponding to the first row of the backlight sources  101  from the buffer memory  204 . For example, when scanning to a backlight source  101  in a third column of the first row according to the scanning axis X, the local-dimming control circuitry  203  reads brightness information corresponding to a backlight source  101  in a fourth column of the first row from the buffer memory  204 . 
     A time interval between the time when the panel completes scanning and the time when next scanning starts is defined as a vertical blanking time. Therefore, according to some embodiments, before the local-dimming control circuitry  203  completes scanning of a frame F, the timing control circuitry  201  generates a transmission packet of a next frame F within the vertical blanking time, and the transmission packet is stored in the buffer memory  204  by the local-dimming control circuitry  203  in advance. In this way, the buffer memory  204  provides a buffer to avoid the problem of screen tearing due to an excessively large difference between a brightness information generating speed of the timing control circuitry  201  and a scanning speed of the local-dimming control circuitry  203 . 
     According to some embodiments, the timing control circuitry  201  transmits a synchronization signal Vsync to the local-dimming control circuitry  203 , so that the brightness information generating speed is synchronized with the panel scanning speed.  FIG.  5    is a schematic diagram of a timing control circuitry and a local-dimming control circuitry according to a second embodiment; and  FIG.  6    is a schematic diagram of a differential signal according to some embodiments. Referring to  FIG.  5    and  FIG.  6    together, according to some embodiments, the timing control circuitry  201  includes the TCON  2015 , a plurality of first differential circuits  2011 , a second differential circuit  2012 , a third differential circuit  2013 , and a fourth receiving circuit  2014 ; and the local-dimming control circuitry  203  includes a plurality of first receiving circuits  2031 , a second receiving circuit  2032 , a third receiving circuit  2033 , and a fourth differential circuit  2034 , and the BCON  2035 . According to some embodiments, the plurality of first differential circuits  2011  of the timing control circuitry  201  are respectively connected to the plurality of first receiving circuits  2031  of the local-dimming control circuitry  203 ; and the second differential circuit  2012  and the third differential circuit  2013  of the timing control circuitry  201  are respectively connected to the second receiving circuit  2032  and the third receiving circuit  2033  of the local-dimming control circuitry  203 . According to some embodiments, the second differential circuit  2012  transmits the synchronization signal Vsync to the second receiving circuit  2032  at the beginning of each frame F, and the local-dimming control circuitry  203  begins scanning after receiving the synchronization signal Vsync. Therefore, the generation speed of brightness information within a range of each frame F is synchronized with the scanning speed of the local-dimming control circuitry  203 . According to some embodiments, the third differential circuit  2013  transmits a data enable signal DEN to the third receiving circuit  2033  during a period of each frame F. The data enable signal DEN is used for marking an effective period E of a transmission packet transmitted by a first differential signal Data, to ensure the correctness of the transmission packet within a range of the effective period E. 
     According to some embodiments, the local-dimming control circuitry  203  generates a loopback packet according to a second customized content specification, and the fourth differential circuit  2034  transmits the loopback packet to the fourth receiving circuit  2014  of the timing control circuitry  201  according to a differential voltage level. According to some embodiments, the loopback packet includes compensation data, such as electrical compensation data or optical compensation data. According to some embodiments, the second customized content specification is used for compiling sensing information of a plurality of backlight sources  101  into the loopback packet, so that the loopback packet is adapted to be transmitted through the fourth differential circuit  2034 . According to some embodiments, the second customized content specification is the same as the first customized content specification. 
     Drive currents of different backlight sources  101  may be different due to process variation or differences in loss cycles, thereby resulting in different brightness of different partitions on a same backlight panel  102 . Therefore, according to some embodiments, each of the backlight sources  101  is coupled to a current detection circuit, and the current detection circuit measures the drive currents of the backlight sources  101  and generates the sensing information. The local-dimming control circuitry  203  receives the sensing information measured by each current detection circuit and generates the loopback packet. 
     According to some embodiments, the backlight control device  200  includes an optical sensing circuitry, where the optical sensing circuitry is configured to measure light source intensities of the backlight sources  101  to generate the sensing information. The local-dimming control circuitry  203  receives the sensing information corresponding to each of the backlight sources  101  and generates the loopback packet. The optical sensing circuitry may be, but is not limited to, a photodiode, a phototransistor, a photoresistor, a visible or invisible optical sensor. 
     According to some embodiments, the loopback packet includes a start byte, a data sequence, and an end byte. According to some embodiments, the start byte includes control information. The control information may be used for informing the timing control circuitry  201  of a quantity of bits of the sensing information. According to some embodiments, the control information enables the timing control circuitry  201  to identify the sensing information stored in each loopback packet, and each of the backlight sources  101  corresponding to the sensing information. Referring to  FIG.  3 A , the rest may be deduced by analogy, and taking sensing information of 12 bits as an example, DATA0[7:0] (8 bits) of the first field and DATA0[11:8] (4 bits) of the second field of the data sequence correspond to sensing information measured from the No. 0 backlight source  101 . 
       FIG.  7    is a schematic diagram of a timing control circuitry and a local-dimming control circuitry according to a third embodiment. Referring to  FIG.  7   , according to some embodiments, the timing control circuitry  201  includes the TCON  2015 , the first differential circuit  2011 , and the fourth receiving circuit  2014 ; and the local-dimming control circuitry  203  includes the first receiving circuit  2031 , the fourth differential circuit  2034 , and the BCON  2035 , where the first receiving circuit  2031  is electrically coupled to the first differential circuit  2011  through a pair of transmission lines, the fourth differential circuit  2034  is connected to the first receiving circuit  2031  in parallel, and the fourth receiving circuit  2014  is connected to the first differential circuit  2011  in parallel. Therefore, according to some embodiments, a plurality sets of differential circuits use the same pair of transmission lines, which reduces the quantity of wires. In this way, the differential circuits allow half-duplex transmission between the timing control circuitry  201  and the local-dimming control circuitry  203 . Referring to  FIG.  1    together, the backlight control device  200  allows packet transmission in a transmission direction a or in a transmission direction b at the same time. According to some embodiments, the first differential circuit  2011  transmits the transmission packet according to a first duty ratio, the fourth differential circuit  2034  transmits the loopback packet according to a second duty ratio, and the first duty ratio is different from the second duty ratio. For example, the differential signal transmitted by the first differential circuit  2011  has the first duty ratio of 50%, and the differential signal transmitted by the fourth differential circuit  2034  has the second duty ratio of 80%. Therefore, the first receiving circuit  2031  parses the differential voltage level according to the first duty ratio of 50% to obtain the transmission packet, and the second receiving circuit  2032  parses the differential voltage level according to the second duty ratio of 80% to obtain the loopback packet. In this way, the differential circuits allow full-duplex transmission between the timing control circuitry  201  and the local-dimming control circuitry  203 . Referring to  FIG.  1    together, the backlight control device  200  allows packet transmission in a transmission direction c at the same time. 
     According to some embodiments, the backlight control device  200  is adapted to control the backlight sources  101  and a liquid crystal panel  210 .  FIG.  8    is a schematic block diagram of a backlight control device and a liquid crystal panel according to some embodiments. Referring to  FIG.  8   , according to some embodiments, the timing control circuitry  201  of a backlight control device  200 ′ generates a differential signal S, and a differential voltage level of the differential signal S transmits the transmission packet to the local-dimming control circuitry  203 , to control the backlight sources  101 . In addition, the timing control circuitry  201  transmits a gate in panel (GIP) signal and a drive data signal Drive to the liquid crystal panel  210 , to control the liquid crystal panel  210 . The GIP signal allows the timing control circuitry  201  to scan and drive the liquid crystal panel  210  of the array, and the drive data signal Drive allows the timing control circuitry  201  to adjust RGB display of the liquid crystal panel  210 . In this way, the timing control circuitry  201  simultaneously coordinates the display of the liquid crystal panel  210  and the backlight panel  102 , which reduces the quantity of panel control chips and the coordination problem among the chips. 
       FIG.  9 A  is a schematic diagram of a backlight control device, a backlight panel, and a liquid crystal panel according to some embodiments; and  FIG.  9 B  is a schematic diagram of a backlight control device, a backlight panel, and a liquid crystal panel according to some other embodiments. Referring to  FIG.  9 A  first, according to some embodiments, the backlight control device  200  includes the local-dimming control circuitry  203 , the timing control circuitry  201 , a Gamma circuitry  207 , a power supply management circuitry  208 , and a zoom control circuitry  205 . The Gamma circuitry  207  performs voltage correction of a grayscale image. The power supply management circuitry  208  is in charge of power supply management of each circuitry. The zoom control circuitry  205  performs zoom processing on image data D of different resolutions, to meet a display specification of the liquid crystal panel  210  or the backlight panel  102 . According to some embodiments, the zoom control circuitry  205  is externally connected to the timing control circuitry  201  through a flat cable  209 . According to some embodiments, referring to  FIG.  9 B , the zoom control circuitry  205  and the timing control circuitry  201  are integrated into a system-on-chip  206 . 
     As described above, according to some embodiments, the local-dimming control circuitry  203  includes the buffer memory  204 . After the timing control circuitry  201  rapidly transmits the transmission packet to the local-dimming control circuitry  203  through the differential circuit, the local-dimming control circuitry  203  temporarily stores the transmission packet in the buffer memory  204 , to provide a buffer for the generation speed and scanning speed of the transmission packet. According to some embodiments, the timing control circuitry  201  transmits the synchronization signal Vsync to the local-dimming control circuitry  203 , to make the local-dimming control circuitry  203  synchronized with the timing control circuitry  201 , and avoid the problem of screen tearing. According to some embodiments, the local-dimming control circuitry  203  transmits the loopback packet including the compensation data of the backlight sources  101  to the timing control circuitry  201 , so that the timing control circuitry  201  can adjust the brightness information corresponding to each of the backlight sources  101  according to the compensation data. According to some embodiments, the backlight control device  200  provides simplex, half-duplex, or full-duplex data transmission, to meet simultaneous or non-simultaneous data transmission needs.