System architecture for high-density mini / micro LED backlight applications

Abstract

The present disclosure relates to a system architecture for high-density mini / micro LED backlight applications. A non-emissive display includes a backlight controller that sends pulses to row and column drivers driving a backlight area during each sub-frame of a plurality of frames. The row driver counts each pulse to maintain a total pulse count, and when it equals a first number indicating how many row drivers there are, resets the total pulse count. If the total pulse count does not equal the first number and if the total pulse count equals a second number indicating in which sub-frame the first driver will be activated, each row driver activates its channel and waits for the next pulse. If the total pulse count does not equal the first number and the second number, each row driver waits for the next pulse. Each column driver activates its channel in response to receiving each pulse.

Description

Technical Field

[0001] The present disclosure relates to the field of display technologies, and more particularly to an architecture for driving a light-emitting diode (LED)-based backlight of a non-emissive display in a manner that allows controlling a greater number of zones without consuming excessive area. Background Art

[0002] Many electronic devices, such as smart phones, smart glasses, smart watches, tablet computers, laptop computers, monitors, and televisions, use display panels to display information to users. Such display panels are organized as a two-dimensional matrix of rows and columns, and the intersections between the rows and columns represent display elements, such as zones (in the case of non-emissive displays) and pixels (in the case of emissive displays).

[0003] The present disclosure relates to non-emissive display panels. An exemplary type of non-emissive display is a liquid crystal display (LCD), which is commonly used, for example, in televisions, and an exemplary type of emissive display is an organic light-emitting diode (OLED) display, which is commonly used, for example, in smart phones.

[0004] Figure 1A An exemplary LCD-based non-emissive display panel 12 incorporated into a stand-alone display 10 is shown. The non-emissive display panel 12 is formed by a two-dimensional matrix of display zones, and an exemplary display zone is indicated by reference numeral 15. Each display zone 15 includes a plurality of pixels, and each pixel includes at least one red sub-pixel, at least one green sub-pixel, and at least one blue sub-pixel.

[0005] The illustrated display zone 15 represents each display zone within the non-emissive display panel 12 and includes liquid crystals LC 16a for modulating the display of red, liquid crystals LC 16b for modulating the display of green, and liquid crystals LC 16c for modulating the display of blue. The liquid crystals 16a-16c are arranged above a backlight for the zone, which is formed here by one or more light-emitting diodes (LEDs) 17.

[0006] Additionally or alternatively, the liquid crystals 16a, 16b, and 16c may modulate the display of colors other than red, green, and blue. Further, the LEDs 16a-16c may be connected in series and / or in parallel.

[0007] The specific layer structure forming the non-emissive display panel 12 may be found in Figure 1BAs seen in [description], the backlight backplane 13 can be observed to carry backlight LEDs 17, and the color conversion and diffusion layer 19 is disposed above the backlight LEDs 17. The backlight LEDs 17 can be so-called "mini" or "micro" LEDs. The liquid crystal 16 is disposed above the color conversion and diffusion layer 19 (or multiple color conversion and diffusion layers), and the display glass layer 18 is disposed above the liquid crystal 16. The backlight backplane 13 and the LEDs 17 can be collectively referred to as the matrix 14.

[0008] The LED 17 emits light, which is then converted into different red, green, and blue light beams (or, for example, light beams of colors other than red, green, and blue) by the color conversion and diffusion layer 19. This light beam then passes through the liquid crystal 16 and exits from the display glass 18, thereby forming an image. The voltage across each individual liquid crystal 16 is modulated such that those individual liquid crystals change their transparency, thereby modulating the amount of light passing through those liquid crystals. When the red, green, and blue light beams (or other colored light beams, as described above) pass through the liquid crystal 16, different colors are displayed by modulating the intensity of the red, green, and blue light beams by the operation of the liquid crystal. Since the light source itself is the LED 17 with a given area, rather than pixels within that given area, the display panel 12 is considered non-emissive (e.g., having non-emissive pixels located within the emission area, and each area provides light to multiple pixels).

[0009] In operation, each area is addressed by the simultaneous activation of the corresponding row driver and column driver of that area, causing current to flow from the row driver through the LEDs of that area to the column driver; alternatively, the current can flow from the column driver through the LEDs of that area to the row driver. This current can be in the form of a pulse and is modulated by its amplitude or width. The activation is divided into different frames, the row activation is multiplexed on each frame, one or more rows are activated simultaneously, and the column activation is synchronized with the row activation; alternatively, the column activation can be multiplexed on each frame, one or more columns are activated simultaneously, and the row activation can be multiplexed on each time frame.

[0010] Today, the number of backlight areas of display panels is constantly increasing, and as a result, the size of the LEDs in those backlight areas is constantly decreasing. Therefore, the number of row drivers and column drivers for operating these backlight areas increases, consuming area while increasing complexity and cost. Therefore, further development is needed. Summary of the Invention

[0011] Disclosed herein is a display, comprising: a plurality of first drivers, each first driver having a plurality of channels; a plurality of second drivers, each second driver having at least one channel;

[0012] A display element matrix including a first line and a second line arranged as a backlight area, where each first line is coupled between one channel of a plurality of channels of one of a plurality of first drivers and at least one channel of one of a plurality of second drivers; and a backlight controller coupled to the plurality of first drivers and the plurality of second drivers.

[0013] The backlight controller is configured to send a synchronization signal indication to the plurality of first drivers and the plurality of second drivers during each sub-frame of a plurality of frames.

[0014] Each first driver is configured to: count each received synchronization signal indication to maintain a total count of synchronization signal indications; reset the total count of synchronization signal indications when the total count of synchronization signal indications is equal to a first quantity indicating how many first drivers there are among the plurality of first drivers; activate its plurality of channels and then wait for the next synchronization signal indication when the total count of synchronization signal indications is not equal to the first quantity and the total count of synchronization signal indications is equal to a second quantity, where the second quantity indicates in which sub-frame the first driver will be activated; and wait for the next synchronization signal indication when the total count of synchronization signal indications is not equal to the first quantity and the total count of synchronization signal indications is not equal to the second quantity.

[0015] Each second driver is configured to activate at least one of its channels in response to receiving each synchronization signal indication.

[0016] The plurality of first drivers may include a plurality of row drivers, the first line of the backlight area may include rows of the backlight area, the plurality of second drivers may include a plurality of column drivers, and the second line of the backlight area may include columns of the backlight area.

[0017] The plurality of second drivers may include a plurality of row drivers, the second line of the backlight area may include rows of the backlight area, the plurality of first drivers may include a plurality of column drivers, and the first line of the backlight area may include columns of the backlight area.

[0018] The synchronization signal indication may be a pulse, a bit, or a byte.

[0019] The backlight controller may send the synchronization signal indication at the start of each sub-frame of each of the plurality of frames.

[0020] The backlight controller may send the synchronization signal indication to the plurality of first drivers and the plurality of second drivers via a first bus.

[0021] The plurality of first drivers and the plurality of second drivers may send signals to the backlight controller via a second bus.

[0022] A first daisy-chain connection can be formed between a plurality of first drivers and a plurality of second drivers, and the plurality of first drivers and the plurality of second drivers send signals to a backlight controller through the first daisy-chain connection.

[0023] A second daisy-chain connection can be formed between the plurality of first drivers and the plurality of second drivers, and the backlight controller sends a synchronization signal indication to the plurality of first drivers and the plurality of second drivers through the second daisy-chain connection.

[0024] A first daisy-chain connection can be formed between a plurality of first drivers and a plurality of second drivers, and the plurality of first drivers and the plurality of second drivers send signals to a backlight controller through the first daisy-chain connection.

[0025] This document also discloses a display, including: a plurality of first drivers, each first driver having a plurality of channels; a daisy-chain connection formed between the plurality of first drivers; a plurality of second drivers, each second driver having at least one channel; a display element matrix arranged as a first line and a second line of a backlight area, each first line of the backlight area being coupled between one of the plurality of channels of one of the plurality of first drivers and at least one channel of one of the plurality of second drivers; and a backlight controller coupled to the plurality of first drivers and the plurality of second drivers.

[0026] The backlight controller is configured to send a synchronization signal indication to the plurality of first drivers and the plurality of second drivers during each sub-frame of a plurality of frames.

[0027] Each first driver is configured to: when the received synchronization signal indication is the first synchronization signal indication received after the start of the current frame and the first driver is activated in the first sub-frame of each frame, activate the plurality of channels of the first driver and output a trigger signal pulse to the daisy chain, and then wait for the next synchronization signal indication; when the received synchronization signal indication is the first synchronization signal indication received after the start of the current frame and the first driver is not activated in the first sub-frame of each frame, the first driver receives a trigger signal pulse after receiving the synchronization signal indication, the received synchronization signal indication is not the first synchronization signal indication received after the start of the current frame, and the first driver receives a trigger signal pulse after receiving the synchronization signal indication, activate the plurality of channels of the first driver and output a trigger signal pulse to the daisy chain, and then wait for the next synchronization signal indication; and when the received synchronization signal indication is not the first synchronization signal indication received after the start of the current frame and the first driver does not receive a trigger signal pulse after receiving the synchronization signal indication, wait for the next synchronization signal indication.

[0028] Each second driver is configured to activate its at least one channel in response to receiving each synchronization signal indication.

[0029] The plurality of first drivers may include a plurality of row drivers, a first line of the backlight area may include rows of the backlight area, the plurality of second drivers may include a plurality of column drivers, and a second line of the backlight area may include columns of the backlight area.

[0030] The plurality of second drivers may include a plurality of row drivers, a second line of the backlight area may include rows of the backlight area, the plurality of first drivers may include a plurality of column drivers, and a first line of the backlight area may include columns of the backlight area.

[0031] The synchronization signal indication may be a pulse, a bit, or a byte.

[0032] The backlight controller may send a synchronization signal indication at the start of each subframe of each of the plurality of frames.

[0033] The backlight controller may send a synchronization signal indication to the plurality of first drivers and the plurality of second drivers via a first bus.

[0034] The plurality of first drivers and the plurality of second drivers may send signals to the backlight controller via a second bus.

[0035] A first daisy-chain connection may be formed between the plurality of first drivers and the plurality of second drivers, and the plurality of first drivers and the plurality of second drivers send signals to the backlight controller via the first daisy-chain connection.

[0036] A second daisy-chain connection may be formed between the plurality of first drivers and the plurality of second drivers, and the backlight controller sends a synchronization signal indication to the plurality of first drivers and the plurality of second drivers via the second daisy-chain connection.

[0037] A first daisy-chain connection may be formed between the plurality of first drivers and the plurality of second drivers, and the plurality of first drivers and the plurality of second drivers send signals to the backlight controller via the first daisy-chain connection. Description of the Drawings

[0038] Figure 1A is a graphical representation of a known non-emissive display.

[0039] Figure 1B is Figure 1A a graphical representation of a cross-section of the non-emissive display of

[0040] Figure 2 is a block diagram of the non-emissive display disclosed herein.

[0041] Figure 3 is Figure 2 a graphical representation of a display matrix of the display of

[0042] Figure 4is a block diagram of a first embodiment showing the interconnection between a backlight controller, a row driver, and a column driver. Figure 3

[0043] Figure 5 is a block diagram of a second embodiment showing the interconnection between a backlight controller, a row driver, and a column driver. Figure 3

[0044] Figure 6 is a block diagram of a third embodiment showing the interconnection between a backlight controller, a row driver, and a column driver. Figure 3

[0045] Figure 7 is Figure 3 a graphical representation of the time-division operation of a display matrix.

[0046] Figure 8 is a flowchart of a first technique for operating a display matrix when the backlight controller, row driver, and column driver are connected as shown in Figures 4-6 Figure 3

[0047] Figure 9 is a block diagram of a fourth embodiment showing the interconnection between a backlight controller, a row driver, and a column driver. Figure 3

[0048] Figure 10 is a block diagram of a fifth embodiment showing the interconnection between a backlight controller, a row driver, and a column driver. Figure 3

[0049] Figure 11 is a block diagram of a sixth embodiment showing the interconnection between a backlight controller, a row driver, and a column driver. Figure 3

[0050] Figure 12 is a block diagram showing more details of a row driver of an embodiment. Figures 9-11

[0051] Figure 13 is a flowchart of a second technique for operating a display matrix when the backlight controller, row driver, and column driver are connected as shown in Figures 9-12 Figure 3 Detailed Description

[0052] The following disclosure enables those skilled in the art to make and use the subject matter disclosed herein. Without departing from the spirit and scope of the present disclosure, the general principles described herein can be applied to embodiments and applications other than those described in detail above. The present disclosure is not intended to be limited to the embodiments shown, but rather to be in accord with the broadest scope consistent with the principles and features disclosed or suggested herein. Note that in the following description, unless otherwise stated, any resistor or resistance described is a discrete device and not merely an electrical lead between two points. Thus, any resistor or resistance described as being coupled between two points has a greater resistance than the lead between those two points, and such a resistor or resistance cannot be construed as a lead. Similarly, unless otherwise stated, any capacitor or capacitance described is a discrete device and is not parasitic unless otherwise stated. Additionally, unless otherwise stated, any inductor or inductance described is a discrete device and is not parasitic unless otherwise stated.

[0053] Now refer to Figure 2 Describe the design of the display 30 that utilizes the non-emissive display panel 40. The display 30 includes an interface controller 33 that receives input from an external device 27, such as a system-on-chip (SOC) or a microcontroller, the external device including an input processor 28 (such as a GPU) and a system memory 29 that communicates bidirectionally with the input processor 28. The input processor 28 receives input image information and collaborates with the system memory 29 to generate an output to the interface controller 33 that indicates the next frame of image data to be displayed by the display panel 40. The interface controller 33 processes the output from the input processor 28 and provides an output to a timing controller 34 and a display power management circuit 37. The timing controller 34 coordinates with a backlight controller 35 to provide control signals to row drivers 41A, …, 41X and column drivers 42A, …, 42Y associated with zones of the backlight panel 14. The backlight panel 14 is divided into an array of NxM zones. Each zone shown within the backlight panel 14 may include a plurality of LEDs connected in series, and these LED strings may be connected in parallel with each other. The LCD display driver 36 provides control signals to the liquid crystal 38 to effect coordination between the backlight panel 14 and the liquid crystal 38, thereby enabling image display. The display panel 40 includes a switch driver 99 for controlling switches within the display panel 40.

[0054] In some instances, the row drivers 41A, …, 41X may be combined into one or more row drivers, the column drivers 42A, …, 42Y may be combined into one or more column drivers, and these one or more row drivers and these one or more column drivers may be integrated within or on the backlight panel 14.

[0055] Each row driver 41A, …, 41X can be a single integrated circuit, or can occupy a given area within an integrated circuit, and can include at least two registers Reg1, Reg2 and a counting circuit Ctr.

[0056] Details of the interconnections within the display panel 40 will be described below.

[0057] Regarding the connection between the row drivers 41A, …, 41X and the zones, and the connection between the column drivers 42A, …, 42Y and the zones, the electrical arrangement can be such that each row driver 41A, …, 41X is coupled to the anodes of the LEDs within the zone of the row it serves, and such that each column driver 42A, …, 42Y is coupled to the cathodes of the LEDs within the zone of the column it serves. Alternatively, the electrical arrangement can be such that each row driver 41A, …, 41X is coupled to the cathodes of the LEDs within the zone of the row it serves, and such that each column driver 42A, …, 42Y is coupled to the anodes of the LEDs within the zone of the column it serves.

[0058] Figure 3 A general block diagram of the display panel 40 is shown here. Here, the display panel 40 includes a matrix of NxM zones. Each of the X row drivers 41A, …, 41X has z channels (for example, row driver 41A has z channels and thus operates z rows, row driver 41B has z channels and thus operates z rows, etc.). Each of the Y column drivers 42A, …, 42Y has k channels (for example, column driver 42A has k channels and thus operates k rows, column driver 42B has k channels and thus operates k rows, etc.). The number z of channels owned by each row driver 41A, …, 41X can be any suitable integer, and the number k of channels owned by each column driver 42A, …, 42Y can be any suitable integer, and z and k do not need to be equal to each other (but can be equal if desired). The number z of channels of the X row drivers 41A, …, 41X can vary from row driver to row driver. In the same way, the number k of channels of the Y column drivers can vary from column driver to column driver.

[0059] Reference will now additionally be made to Figure 4 describe the interconnection between the backlight controller 35 operating according to the first technique and the row drivers 41A, …, 41X and the column drivers 42A, …, 42Y.

[0060] In Figure 4In the first possible configuration shown in FIG. 1, a first bus transfers data and control signals from a backlight controller 35 to row drivers 41A, ..., 41X and column drivers 42A, ..., 42Y, and a second bus transfers data and control signals from the row drivers 41A, ..., 41X and column drivers 42A, ..., 42Y back to the backlight controller. Control signals sent by the backlight controller 35 to the row drivers and column drivers via the first bus include a synchronization signal Sync, which is described below as arriving in the form of a pulse, but can be replaced by a digital signal if desired.

[0061] In Figure 5 In the second possible configuration shown in FIG. 2, a bus transfers data and control signals from a backlight controller 35 to row drivers 41A, ..., 41X and column drivers 42A, ..., 42Y, and a daisy-chain connection transfers data and control signals from the row drivers 41A, ..., 41X and column drivers 42A, ..., 42Y back to the backlight controller 35. The daisy-chain connection starts from the last column driver 42Y, passes through the penultimate column driver 42B, and so on until it reaches the first column driver 42A. The daisy-chain connection continues from the first column driver 42A to the last row driver 41X, passes through the penultimate row driver 41B, and so on until it reaches the first row driver 41A. The output of the daisy-chain connection is transferred from the first row driver 41A to the backlight controller 35. Data and control signals generated and sent by an upstream driver pass through each downstream driver until they are transferred to the backlight controller. For example, data and control signals generated by the last column driver 42Y are transferred to the penultimate column driver 42B, and so on until they are transferred to the first row driver 41A, and then from the first row driver 41A to the backlight controller 35. Similarly, data and control signals generated by the penultimate column driver 42B are sequentially transferred through the preceding column drivers (here 42A) to the last row driver 42Y, and from the last row driver 42Y sequentially through the preceding row drivers (here 41B and 41A), and then transferred to the backlight controller 35. Control signals sent by the backlight controller 35 to the row drivers and column drivers via the bus include a synchronization signal Sync, which is described below as arriving in the form of a pulse, but can be replaced by a digital signal if desired.

[0062] In as Figure 6In the third possible configuration shown, a first daisy-chain connection conveys data and control signals from the backlight controller 35 to the row drivers 41A, …, 41X and the column drivers 42A, …, 42Y. This daisy-chain connection starts at the first row driver 41A in the connection to receive input from the backlight controller 35 and extends sequentially through each row driver until it reaches the first column driver 42A and extends sequentially through each column driver until it reaches the last column driver 42Y. A second daisy-chain connection conveys data and control signals from the row drivers 41A, …, 41X and the column drivers 42A, …, 42Y back to the backlight controller 35. This daisy-chain connection starts at the last column driver 42Y, extends sequentially through each column driver until it reaches the first column driver 42A, extends from the first column driver 42A to the last row driver 41X, extends from the last row driver 41X until it reaches the first row driver 41A, and extends from the first row driver 41A to provide an output to the backlight controller 35. The control signals sent by the backlight controller 35 to the row drivers and column drivers via the first daisy-chain connection include a synchronization signal Sync, which is described below as arriving in the form of a pulse but can be replaced by a digital signal if desired.

[0063] In Figures 4 to 6 the positions of the row drivers 41A, …, 41X and the column drivers 42A, …, 42Y in the buses and daisy-chains shown are variable. For example, the first element on the right can be a row driver, then a column driver, two row drivers, another column driver, etc.

[0064] Typically, under the control of the backlight controller 35, operations are performed in a manner of operating one row driver 41A, ..., 41X at a time. As Figure 7 shown, the operations are divided into frames, each frame is divided into multiple sub-frames, and the number of sub-frames is equal to the number of row drivers 41A, …, 41X. During each sub-frame, different row drivers 41A, …, 41X are activated so that each row driver is activated during a different sub-frame of each frame. During each sub-frame, a given row driver 41A, …, 41X associated with that sub-frame activates each of its channels (and its associated rows) in a given order (e.g., sequential order, non-sequential order) such that one channel is activated at a time. When each channel (and its associated row) of the row drivers 41A, …, 41X is activated, each column driver 42A, …, 42Y is activated.

[0065] Now also referring to Figure 8The flowchart 100 of FIG. 0 gives the operation details. Initially, at the start of each frame, or at another suitable time (e.g., when the device in which the display 30 is incorporated is powered on), the backlight controller 35 sends configuration signals to the row drivers 41A, …, 41X (block 101). For each row driver 41A, …, 42Y, these configuration signals set the first register Reg1 to be equal to the total number of row drivers 41A, …, 41X present (designated as Number_Of_Row_Drivers), and the value in Reg1 varies from 0 indicating only one row driver present to X - 1 indicating X row drivers present. For each row driver 41A, …, 42Y, the configuration signal also sets the second register Reg2 to the position of that individual row driver in the execution sequence of the row drivers (designated as Row_Driver_Order) - the values that the register Reg2 can hold vary from 0 indicating that a given row driver will be activated during the first sub - cycle of each period to Z - 1 indicating that a given row driver will be activated during the last sub - cycle of each period.

[0066] At the start of each sub - frame, the backlight controller 35 sends a synchronization signal pulse to the row drivers 41A, …, 41X and the column drivers 42A, …, 42Y (block 102). The counting circuit Ctr within each row driver 41A, …, 41X counts the number of synchronization signal pulses received during that period (block 103). If the number of synchronization signal pulses received (designated as Sync_Count) is equal to the total number of row drivers Number_Of_Row_Drivers (block 104), then the row drivers 41A, …, 41X reset the Sync_Count in their counting circuit Ctr back to 0 (block 105). If the number of synchronization signal pulses Sync_Count received by a given row driver 41A, …, 41X is equal to the position of that row driver in the execution sequence Row_Driver_Order (block 106), then that row driver starts each of its channels in the current sub - frame in a given channel order (e.g., sequentially) (block 107). If Sync_Count is not equal to Row_Driver_Order, or if it is equal and the steps in block 107 have been executed, then the given row driver waits for the next synchronization signal pulse (block 108).

[0067] The column drivers 42A, …, 42Y start their channels while starting the channels of each row driver 41A, …, 41X according to the image data received from the backlight controller 35. In this way, the illumination provided by each zone can be controlled by the image data - the zones whose associated pixels are intended to display black can remain un - illuminated, while the zones whose associated pixels are intended to have varying intensities can each independently set their own intensities.

[0068] Reference will now be made additionally to Figures 9 to 12 Describe the interconnection between the backlight controller 35 operating according to the second technique and the line drivers 41A, …, 41X and the column drivers 42A, …, 42Y. In these embodiments described below, the register Reg2 in each of the line drivers 41A, …, 42Y may be a single-bit register. In addition to this, Figure 9 The configuration of is the same as that of Figure 4 except that here the daisy chain connects the line drivers 41A, …, 41X in a loop, where the line driver 41A is the first line driver in the daisy chain and the line driver 41X is the last line driver in the daisy chain, and this daisy chain connection is used to transmit the trigger signal pulses generated by the line drivers. Similarly, Figure 10 The configuration of is the same as that of Figure 5 except that here the second daisy chain connects the line drivers 41A, …, 41X in a loop, where the line driver 41A is the first line driver in the second daisy chain and the line driver 41X is the last line driver in the second daisy chain, and this second daisy chain connection is used to transmit the trigger signal pulses generated by the line drivers. Similarly, Figure 11 The configuration of is the same as that of Figure 6 except that here the third daisy chain connects the line drivers 41A, …, 41X in a loop, where the line driver 41A is the first line driver in the third daisy chain and the line driver 41X is the last line driver in the daisy chain, and this third daisy chain connection is used to transmit the trigger signal pulses generated by the line drivers. As shown in Figure 12 each of the line drivers 41A, …, 41X has a SCAN_IN input terminal for receiving the trigger signal pulses and a SCAN_OUT output terminal for generating or transmitting the trigger signal pulses.

[0069] Reference will now be made additionally to Figure 13The flowchart 110 of FIG. gives operational details. Initially, at the start of each frame, or at another suitable time (e.g., when the display 30 is powered on in the device to which it is incorporated), the backlight controller 35 sends configuration signals to the row drivers 41A, …, 41X (block 111). For each row driver 41A, …, 42Y, these configuration signals set the first register Reg1 to the total number of row drivers 41A, …, 41X present (designated as Number_Of_Row_Drivers), and the value in Reg1 varies from 0 indicating only one row driver is present to X - 1 indicating X row drivers are present. For each row driver 41A, …, 42Y, the configuration signal also sets the second register Reg2 to an indication of whether that row driver 41A, …, 42Y is the first row driver to be activated (e.g., to be activated during the first sub - cycle) in each period. If a given row driver 41A, …, 42Y is to be activated first in each period, its register Reg2 is set to the value 1, otherwise its register Reg2 is set to the value 0.

[0070] At the start of each sub - frame, the backlight controller 35 sends a synchronization signal pulse to the row drivers 41A, …, 41X and the column drivers 42A, …, 42Y (block 112). Each row driver 41A, …, 41X determines whether the synchronization signal pulse it receives is the first synchronization signal pulse it has received after a reset, which occurs at the end of the previous frame or the start of the current frame (block 113). The identification of the synchronization signal pulse is determined by a signal transition. Once each row driver 41A, …, 41X has received the first synchronization signal pulse after a reset, each row driver latches an internal bit, which remains latched until a reset. Subsequent synchronization signals are not counted and are ignored until a reset.

[0071] If the synchronization signal pulse is the first synchronization signal pulse that the first row driver 41A, …, 41X has received after a reset, and if the register Reg2 stores a 1 indicating that that row driver is to be activated during the first sub - cycle of each period (block 114), then that row driver executes its row in the current sub - frame within the current frame and generates a trigger signal pulse at its SCAN_OUT output (block 116). Then, that row driver waits for the next synchronization signal pulse and / or a trigger signal at its SCAN_IN input (block 117).

[0072] If the sync signal pulse is the first sync signal pulse received by the row driver after reset (block 113), but the register Reg2 of the row driver stores a zero value (block 114), and a trigger signal pulse is received at the SCAN_IN input of the row driver after the previous sync signal pulse (block 115), then the row driver executes its row in the current subframe within the current frame, generates a trigger signal pulse at its SCAN_OUT output (block 116), and waits for the next sync signal pulse and / or a trigger signal at its SCAN_IN input (block 117).

[0073] If the sync signal pulse is the first sync signal pulse received by the row driver after reset, but the register Reg2 of the row driver stores a zero value (block 114), and no trigger signal pulse is received at the SCAN_IN input of the row driver after the previous sync signal pulse (block 115), then the row driver waits for the next sync signal and / or a trigger signal at its SCAN_IN input (block 117).

[0074] If the sync signal pulse is not the first sync signal pulse received by the row driver after reset (block 113), and a trigger signal pulse is received at the SCAN_IN input of the row driver after the previous sync signal pulse (block 115), then the row driver executes its row in the current subframe within the current frame, generates a trigger signal pulse at its SCAN_OUT output (block 116), and waits for the next sync signal pulse (block 117).

[0075] If the sync signal pulse is not the first sync signal pulse received by the row driver after reset (block 113), and no trigger signal pulse is received at the SCAN_IN input of the row driver after the previous sync signal pulse (block 115), then the row driver waits for the next sync signal and / or a trigger signal at its SCAN_IN input (block 117).

[0076] Column drivers 42A, …, 42Y start their channels while starting the channels of each row driver 41A, ..., 41X according to the image data received from the backlight controller 35.

[0077] Thus, compared to the embodiment whose operation is described by flowchart 100, the embodiment whose operation is described by flowchart 110 uses trigger signal pulses generated by the row drivers 41A, …, 41X themselves to determine which row driver will be activated during what subframe of the current frame (instead of which row driver will be activated during the first subframe, which is indicated by the register Reg2 of that row driver holding logic 1), as opposed to counting the occurrences of sync signal pulses.

[0078] The described embodiments allow an increase in the number of row drivers present without an increase in the number of column drivers through their use of multiplexing (e.g., dividing each frame into sub-frames).

[0079] It is clear that modifications and variations can be made to what is described and illustrated herein without thereby departing from the scope of the disclosure as defined by the appended claims. For example, each row driver described above can activate its channels simultaneously or in groups of the desired size (e.g., in pairs or triples), rather than in the activation order or sequence. As another example, the operations described above as being performed by the row drivers can alternatively be performed by the column drivers (and then the operations described as being performed by the column drivers can alternatively be performed by the row drivers). As another example, the synchronization signal pulse and the trigger pulse described above can be pulses that transition from low to high and then from high back to low, or can be pulses that transition from high to low and then from low back to high. Additionally, the synchronization signal and / or the trigger signal can be a bit string or a byte string sent to the row drivers and the column drivers, rather than a pulse.

[0080] Although the disclosure has been described with respect to a limited number of embodiments, those skilled in the art who have benefited from the disclosure will understand that other embodiments can be conceived without departing from the scope of the disclosure as disclosed herein. Accordingly, the scope of the disclosure should be limited only by the appended claims.

Claims

1. A display, comprising: a plurality of first drivers, each first driver having a plurality of channels; a plurality of second drivers, each second driver having at least one channel; a display element matrix arranged in a first line and a second line as a backlight area, wherein each first line is coupled between one channel of the plurality of channels of one of the plurality of first drivers and the at least one channel of one of the plurality of second drivers; a backlight controller coupled to the plurality of first drivers and the plurality of second drivers; wherein the backlight controller is configured to send a synchronization signal indication to the plurality of first drivers and the plurality of second drivers during each sub-frame of a plurality of frames; wherein each first driver is configured to: count each received synchronization signal indication, thereby maintaining a total count of the synchronization signal indications; reset the total count of the synchronization signal indications when the total count of the synchronization signal indications is equal to a first quantity indicating how many first drivers there are among the plurality of first drivers; activate the plurality of channels of the first driver and then wait for the next synchronization signal indication when the total count of the synchronization signal indications is not equal to the first quantity and the total count of the synchronization signal indications is equal to a second quantity, the second quantity indicating in which sub-frame the first driver will be activated; and wait for the next synchronization signal indication when the total count of the synchronization signal indications is not equal to the first quantity and the total count of the synchronization signal indications is not equal to the second quantity; and wherein each second driver is configured to activate the at least one channel of the second driver in response to receiving each synchronization signal indication.

2. The display according to claim 1, wherein the plurality of first drivers include a plurality of row drivers; wherein the first line of the backlight area includes rows of the backlight area; wherein the plurality of second drivers include a plurality of column drivers; and wherein the second line of the backlight area includes columns of the backlight area.

3. The display according to claim 1, wherein the plurality of second drivers include a plurality of row drivers; wherein the second line of the backlight area includes rows of the backlight area; wherein the plurality of first drivers include a plurality of column drivers; and wherein the first line of the backlight area includes columns of the backlight area.

4. The display according to claim 1, wherein the synchronization signal indication includes a pulse.

5. The display according to claim 1, wherein the backlight controller sends the synchronization signal indication at the start of each sub-frame of each frame of the plurality of frames.

6. The display according to claim 1, further comprising a first bus, through which the backlight controller sends the synchronization signal indication to the plurality of first drivers and the plurality of second drivers.

7. The display according to claim 6, further comprising a second bus, through which the plurality of first drivers and the plurality of second drivers send signals to the backlight controller.

8. The display according to claim 6, further comprising a first daisy-chain connection formed between the plurality of first drivers and the plurality of second drivers, wherein the plurality of first drivers and the plurality of second drivers send signals to the backlight controller through the first daisy-chain connection.

9. The display according to claim 1, further comprising a second daisy-chain connection formed between the plurality of first drivers and the plurality of second drivers, wherein the backlight controller sends the synchronization signal indication to the plurality of first drivers and the plurality of second drivers through the second daisy-chain connection.

10. The display according to claim 9, further comprising a first daisy-chain connection formed between the plurality of first drivers and the plurality of second drivers, wherein the plurality of first drivers and the plurality of second drivers send signals to the backlight controller through the first daisy-chain connection.

11. A display, comprising: a plurality of first drivers, each first driver having a plurality of channels; a daisy-chain connection formed between the plurality of first drivers; a plurality of second drivers, each second driver having at least one channel; a matrix of display elements arranged as a first line and a second line of a backlight area, wherein each first line of the backlight area is coupled between one of the plurality of channels of one of the plurality of first drivers and the at least one channel of one of the plurality of second drivers; a backlight controller coupled to the plurality of first drivers and the plurality of second drivers; wherein the backlight controller is configured to send a synchronization signal indication to the plurality of first drivers and the plurality of second drivers during each sub-frame of a plurality of frames; wherein each first driver is configured to: when the received synchronization signal indication is the first synchronization signal indication received after the start of the current frame, and the first driver is activated in the first sub-frame of each frame, activate the plurality of channels of the first driver, and output a trigger signal pulse to the daisy-chain, and then wait for the next synchronization signal indication; when the received synchronization signal indication is the first synchronization signal indication received after the start of the current frame, the first driver is not activated in the first sub-frame of each frame, the first driver receives a trigger signal pulse after receiving the synchronization signal indication, the received synchronization signal indication is not the first synchronization signal indication received after the start of the current frame, and the first driver receives a trigger signal pulse after receiving the synchronization signal indication, activate the plurality of channels of the first driver, and output a trigger signal pulse to the daisy-chain, and then wait for the next synchronization signal indication; when the received synchronization signal indication is not the first synchronization signal indication received after the start of the current frame, and the first driver does not receive a trigger signal pulse after receiving the synchronization signal indication, wait for the next synchronization signal indication; and Each of the second drivers is configured to activate at least one channel of the second driver in response to receiving each synchronization signal indication.

12. The display according to claim 11, wherein the plurality of first drivers include a plurality of row drivers; wherein the first line of the backlight area includes rows of the backlight area; wherein the plurality of second drivers include a plurality of column drivers; and wherein the second line of the backlight area includes columns of the backlight area.

13. The display according to claim 11, wherein the plurality of second drivers include a plurality of row drivers; wherein the second line of the backlight area includes rows of the backlight area; wherein the plurality of first drivers include a plurality of column drivers; and wherein the first line of the backlight area includes columns of the backlight area.

14. The display according to claim 11, wherein the synchronization signal indication includes a pulse.

15. The display according to claim 11, wherein the backlight controller transmits the synchronization signal indication at the start of each sub-frame of each of the plurality of frames.

16. The display according to claim 11, further comprising a first bus, through which the backlight controller transmits the synchronization signal indication to the plurality of first drivers and the plurality of second drivers.

17. The display according to claim 16, further comprising a second bus, through which the plurality of first drivers and the plurality of second drivers transmit signals to the backlight controller.

18. The display according to claim 16, further comprising a first daisy-chain connection formed between the plurality of first drivers and the plurality of second drivers, through which the plurality of first drivers and the plurality of second drivers transmit signals to the backlight controller.

19. The display according to claim 11, further comprising a second daisy-chain connection formed between the plurality of first drivers and the plurality of second drivers, through which the backlight controller transmits the synchronization signal indication to the plurality of first drivers and the plurality of second drivers.

20. The display according to claim 19, further comprising a first daisy-chain connection formed between the plurality of first drivers and the plurality of second drivers, through which the plurality of first drivers and the plurality of second drivers transmit signals to the backlight controller.

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