Electronic paper display device and driving method thereof

Abstract

The invention relates to the technical field of display, and discloses an electronic paper display device and a driving method thereof.The electronic paper display device comprises a co-stage electrode module which is arranged on the color film substrate side of an electronic paper module and comprises N independent electrode blocks forming a whole-surface co-stage electrode, the area or resistance value of each independent electrode block is equal, and N is larger than or equal to 2; the current sharing circuit module is used for dynamically adjusting the charging and discharging current of each independent electrode block according to the dynamic adjusting instruction and controlling the current difference of each branch within a preset fluctuation range; the driving control module is used for receiving the balanced current signal output by the current sharing circuit module and sending a dynamic adjusting instruction to the current sharing circuit module through a control signal line; and the driving control module is also used for outputting charging and discharging pulses to each independent electrode block according to a preset time-sharing sequence. According to the device and the driving method thereof, the charging and discharging current difference is reduced, and the reliability of the electronic paper in a high-temperature environment is improved.

Description

Technical Field

[0001] The present invention relates to the field of display technologies, and particularly to an electronic paper display device and a driving method thereof. Background Art

[0002] Cholesteric liquid crystals are widely used in electronic paper displays due to their bistable characteristics. The active cholesteric LCD single-pixel driving architecture mainly consists of a gate line, a source line, a thin-film transistor on the thin-film transistor substrate side, a common line on the color filter substrate side, and a pixel unit. By applying a voltage between the common electrode on the color filter substrate and the pixel electrode on the thin-film transistor substrate, the state of the pixel unit is controlled. Among them, the source line is used to send data to the drain of the thin-film transistor, the gate line controls the gate of the thin-film transistor to control the thin-film transistor to turn on or off, and the pixel unit is connected to the source of the thin-film transistor and is used to receive and store data signals and form an electric field with the common electrode to control the deflection of the liquid crystal.

[0003] In the existing driving scheme, as Figures 1-3 shown, the panel is charged and discharged by alternately applying a voltage sequence of + common voltage → 0 → - common voltage to control the switching of liquid crystal molecules between the H state (vertical alignment state), the P state (planar state), or the FC state (focal conic state). However, as the panel size increases, the uneven distribution of the ac common line resistance leads to a significant difference in the charging and discharging currents. As Figure 4 shown, for a conventional ac common design, all the ac commons on both sides of the trace are directly shorted together in the X PCB, which results in a difference in the charging and discharging currents of each trace. As Figure 5 and Figure 6 shown, the edge trace current is as high as 5 A, while the center trace current is less than 1 A. This current imbalance will cause the bonding pins to burn out due to local overcurrent, and then trigger a chain failure. If one group of pins burns out and the current transfers to another group of pins, it will eventually lead to the failure of the entire module. The prior art has not effectively solved the problem of multi-branch current imbalance under a large-capacitance load, which severely restricts the reliability and service life of large-size electronic paper. Summary of the Invention

[0004] To solve the technical problems in the background art, the present invention proposes an electronic paper display device and a driving method thereof.

[0005] An electronic paper display device proposed by the present invention includes: A common electrode module, configured on the color filter substrate side of the electronic paper module, including N independent electrode blocks forming a whole-surface common electrode, and the area or resistance value of each independent electrode block is equal, where N ≥ 2; A current-sharing circuit module, configured to dynamically adjust the charging and discharging currents of each independent electrode block according to a dynamic adjustment instruction, and control the difference between the branch currents within a preset fluctuation range; A drive control module, configured to receive the balanced current signal output by the current sharing circuit module, and send a dynamic adjustment instruction to the current sharing circuit module through a control signal line; The drive control module is further configured to output charge and discharge pulses to each independent electrode block according to a preset time-sharing sequence, so as to reduce the instantaneous current peak value and coordinate the voltage switching of each independent electrode block.

[0006] Preferably, the current sharing circuit module includes N groups of current sharing units. The input end of each group of current sharing units is electrically connected to the corresponding independent electrode block of the common electrode cutting module through a first conductive trace, and the output end of each group of current sharing units is electrically connected to the current distribution port of the drive control module through a second conductive trace, where the N groups of current sharing units correspond to N independent electrode blocks one by one.

[0007] Preferably, the current sharing unit is specifically a series resistor or an active current sharing integrated circuit.

[0008] Preferably, the dynamic adjustment instruction is specifically a resistance value adjustment instruction or a parameter control instruction for the active current sharing integrated circuit.

[0009] Preferably, the drive control module specifically includes: A drive unit, electrically connecting the current distribution port of the drive unit to the output end of the current sharing circuit module through a second conductive trace; A time-sharing drive logic unit, electrically connected to each independent electrode block of the common electrode cutting module through a third conductive trace.

[0010] Preferably, it further includes: A wiring layout module, integrated on the side of the thin film transistor substrate of the electronic paper module, includes a symmetrically distributed AC common electrode wiring network, and the AC common electrode wiring network is electrically connected to the power output end of the drive control module through a third conductive trace to provide a charge and discharge voltage to the common electrode cutting module.

[0011] Preferably, the AC common electrode wiring network is insulated from the source signal line and the gate signal line of the electronic paper module in different layers.

[0012] Preferably, the preset time-sharing sequence is specifically to preferentially activate the independent electrode blocks at the edge when reaching a preset temperature range.

[0013] Preferably, the preset time-sharing sequence is specifically to sequentially output charge and discharge pulses from the central independent electrode block to the edge independent electrode blocks, and the pulse interval between adjacent independent electrode blocks .

[0014] An electronic paper driving method proposed by the present invention is applied to the electronic paper display device described in any one of the above, and the method includes: Cut the entire common electrode on the color film substrate side of the electronic paper module into N independent electrode blocks; Configure a current sharing circuit for each independent electrode block, and dynamically adjust the charging and discharging currents of each branch through series resistors or active current sharing integrated circuits; Receive the balanced current signal output by the current sharing circuit module, and send a dynamic adjustment instruction to the current sharing circuit module through the control signal line; Output charging and discharging pulses to each independent electrode block in sequence according to a preset time-sharing order, so as to reduce the instantaneous current peak value and coordinate the voltage switching of each independent electrode block; Real-time collect the branch current data corresponding to each independent electrode block, and feedback the branch current data to the drive control module to dynamically correct the current sharing circuit parameters or the preset time-sharing order.

[0015] In the present invention, the proposed electronic paper display device and its driving method cut the entire common electrode on the color film substrate side of the electronic paper module into N independent electrode blocks; configure a current sharing circuit for each independent electrode block, and dynamically adjust the charging and discharging currents of each branch through series resistors or active current sharing integrated circuits; receive the balanced current signal output by the current sharing circuit module, and send a dynamic adjustment instruction to the current sharing circuit module through the control signal line; output charging and discharging pulses to each independent electrode block in sequence according to a preset time-sharing order, so as to reduce the instantaneous current peak value and coordinate the voltage switching of each independent electrode block; real-time collect the branch current data corresponding to each independent electrode block, and feedback the branch current data to the drive control module to dynamically correct the current sharing circuit parameters or the preset time-sharing order. By dividing the common electrode, dynamically adjusting the current by the current sharing circuit, the time-sharing driving strategy and the symmetric wiring layout, the difference in charging and discharging currents is reduced, thereby reducing the temperature of the bonding pins and significantly improving the reliability of the electronic paper in a high-temperature environment. Description of the Drawings

[0016] Figure 1 Schematic diagram of a cholesteric electronic paper module; Figure 2 Schematic diagram of the substrate distribution of a cholesteric electronic paper module; Figure 3 Schematic diagram of the common electrode distribution of a cholesteric electronic paper module; Figure 4 Schematic diagram of the AC common electrode charging and discharging of a cholesteric electronic paper module; Figure 5 Schematic diagram of the driving structure of the prior art; Figure 6 For Figure 5 Schematic diagram of current overcharge of the driving structure; Figure 7 Schematic diagram of the implementation structure of an electronic paper display device proposed by the present invention cut into six independent electrode blocks; Figure 8 A schematic diagram of the equivalent circuit of six independent electrode blocks of an electronic paper display device proposed by the present invention Figure 7 ; Figure 9 A schematic diagram of the driving architecture of an electronic paper display device proposed by the present invention Figure 10 A schematic diagram of the working process of an electronic paper driving method proposed by the present invention Detailed implementation manners

[0017] Referring to Figures 7-9 , an electronic paper display device proposed in this embodiment includes: A common electrode module, disposed on the color filter substrate side of the electronic paper module, includes N independent electrode blocks forming a whole common electrode, and the area or resistance value of each independent electrode block is equal, where N≥2

[0018] A current sharing circuit module, configured to dynamically adjust the charging and discharging current of each independent electrode block according to a dynamic adjustment instruction, and control the current difference of each branch within a preset fluctuation range

[0019] In this embodiment, the current sharing circuit module includes N groups of current sharing units. The input end of each group of current sharing units is electrically connected to the corresponding independent electrode block of the common electrode cutting module through a first conductive trace, and the output end of each group of current sharing units is electrically connected to the current distribution port of the driving control module through a second conductive trace, where the N groups of current sharing units correspond to the N independent electrode blocks one by one. The current sharing circuit module dynamically adjusts the charging and discharging current of each independent electrode block through a series resistor or an active current sharing integrated circuit, controls the current difference of each branch within 10%, suppresses the risk of local overcurrent and heat loss caused by uneven resistance distribution, and at the same time cooperates with the driving control module to achieve balanced current distribution, ensuring the stable operation and life improvement of the electronic paper module in a high-temperature environment

[0020] Specifically, the current sharing unit is specifically a series resistor or an active current sharing integrated circuit

[0021] Specifically, the dynamic adjustment instruction is specifically a resistance value adjustment instruction or a parameter control instruction of an active current sharing integrated circuit

[0022] A driving control module, configured to receive the balanced current signal output by the current sharing circuit module, and send a dynamic adjustment instruction to the current sharing circuit module through a control signal line

[0023] The driving control module is further configured to output charging and discharging pulses to each independent electrode block in a preset time-sharing order, so as to reduce the instantaneous current peak value and coordinate the voltage switching of each independent electrode block

[0024] In this embodiment, the drive control module specifically includes: a drive unit, whose current distribution port is electrically connected to the output end of the current sharing circuit module through a second conductive trace; a time-division drive logic unit, which is electrically connected to each independent electrode block of the common electrode cutting module through a third conductive trace. This ensures balanced current distribution, avoids local overcurrent, and maintains stable drive and long-life operation of the electronic paper module in a high-temperature environment.

[0025] Specifically, when the electronic paper drive is operating normally, the preset time-division sequence is specifically to output charge and discharge pulses sequentially from the central independent electrode block to the peripheral independent electrode blocks, and the pulse interval between adjacent independent electrode blocks , when the temperature at the corresponding position of the electronic paper display device reaches the preset temperature range, such as when the temperature ≥ 80 °C, the preset time-division sequence is specifically to preferentially activate the peripheral independent electrode blocks.

[0026] In this embodiment, it further includes: A trace layout module, integrated on the side of the thin-film transistor substrate of the electronic paper module, includes a symmetrically distributed AC common electrode trace network, and the AC common electrode trace network is electrically connected to the power output end of the drive control module through a third conductive trace to provide a charge and discharge voltage for the common electrode cutting module.

[0027] In this embodiment, the AC common electrode trace network is insulated from the source signal lines and gate signal lines of the electronic paper module in different layers.

[0028] Embodiment 1

[0029] The entire common electrode is cut into 6 independent electrode blocks P1 - P6, and the area of each independent electrode block is equal. The layout is as Figure 7 shown. Assuming the total area of the common electrode is S, the area of each independent electrode block = S / 6, and the cutting path spacing is divided proportionally according to the total size. During the drive control process, the drive control module outputs charge and discharge pulses in the order of P1 → P4 → P2 → P5 → P3 → P6, with an interval of 15 , to avoid instantaneous current concentration. After adjustment, the current of each path can be limited to about 2.9 A, while ensuring that the total discharge current is close, which affects the normal charge and discharge speed. After adjustment, since the current output of all paths is basically the same, the ports are not prone to burnout problems, and the reliability can be guaranteed to pass normally.

[0030] Taking the existing medium-sized products (25 inches to 35 inches) with an AC common electrode of 30 V as an example, the Figure 3 shown panel structure is equivalent to Figure 8The circuit model shown charges and discharges P1 to P6 from both left and right sides in an AC common-emitter configuration. For a pair of charge and discharge paths of P1 to P6, since the distance is close, the 0.5Ω resistor in the middle can be ignored, and the two paths of each branch are equivalent to parallel resistors. The equivalent parallel resistance of each group of P1 to P6 is 2.8Ω. The series resistors in the middle are shown as: 2.3Ω, 32.2Ω, 100Ω, 32.1Ω, 2.4Ω; The initial current flowing through P1 to P6 is calculated as (calculated according to 30V for the AC common-emitter): 10.89A, 6.06A, 1.02A, 1.01A, 5.95A, 10.89A.

[0031] According to Figure 7 the splitting scheme shown, the AC common-emitter is equally divided into 6 independent electrode blocks with the same area according to the position in the legend. Since the areas are the same, the equivalent capacitance C has the same value. C = εS / 4πkd, where C is the capacitance; ε is the dielectric constant; S is the area of the independent electrode block; π is the pi; k is the electrostatic constant; d is the vertical distance. The applied voltage is the same, so according to the charge calculation formula Q = CV; where Q is the charge; C is the capacitance value; V is the voltage. It can be calculated that the charge on the electrode plates on the color film substrate side of P1 to P6 is the same. Therefore, the impact current of each block is 1 / 6 of the total impact current before splitting.

[0032] The total impact current before splitting is calculated according to the charge-current calculation formula. The charge-current calculation formula is I = Q / t, where I is the total impact current before splitting; Q is the total charge; t is the unit time. As Figure 8 shown, each block corresponds to 2 discharge paths, and the discharge current corresponding to a single discharge path is 1 / 2 of the impact current of each block.

[0033] In summary, it is ((10.89A + 6.06A + 1.02A + 1.01A + 5.95A + 10.89A) / 6) / 2 = 2.98A. Therefore, the current of a single discharge path is about 2.98A. Through the calculation of this example, the path of high impact current can be reduced to a safe range without reducing the total discharge speed.

[0034] Referring to Figures 7-10 , an electronic paper driving method proposed by the present invention is applied to the electronic paper display device of any one of the above, and the method includes: Cutting the entire common electrode on the color film substrate side of the electronic paper module into N independent electrode blocks; Configuring a current sharing circuit for each independent electrode block, and dynamically adjusting the charge and discharge current of each branch through a series resistor or an active current sharing integrated circuit; Receiving the balanced current signal output by the current sharing circuit module, and sending a dynamic adjustment instruction to the current sharing circuit module through a control signal line; Output charge and discharge pulses to each independent electrode block in the preset time-sharing sequence to reduce the instantaneous current peak and coordinate the voltage switching of each independent electrode block; Real-time collect the branch current data corresponding to each independent electrode block and feedback the branch current data to the drive control module to dynamically correct the current sharing circuit parameters or the preset time-sharing sequence.

[0035] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. An electronic paper display device, characterized in that, Including: A common electrode module, disposed on the color filter substrate side of the electronic paper module, including N independent electrode blocks forming a whole-surface common electrode, and the area or resistance value of each independent electrode block is equal, where N≥2; A current sharing circuit module, configured to dynamically adjust the charging and discharging currents of each independent electrode block according to a dynamic adjustment instruction, and control the difference between the branch currents within a preset fluctuation range; A driving control module, configured to receive the balanced current signal output by the current sharing circuit module, and send a dynamic adjustment instruction to the current sharing circuit module through a control signal line; The driving control module is further configured to output charging and discharging pulses to each independent electrode block in a preset time-sharing sequence, so as to reduce the instantaneous current peak and coordinate the voltage switching of each independent electrode block.

2. The electronic paper display device according to claim 1, wherein The current sharing circuit module includes N groups of current sharing units. The input end of each group of current sharing units is electrically connected to the corresponding independent electrode block of the common electrode cutting module through a first conductive trace, and the output end of each group of current sharing units is electrically connected to the current distribution port of the driving control module through a second conductive trace, where the N groups of current sharing units correspond to the N independent electrode blocks one by one.

3. The electronic paper display device according to claim 2, wherein The current sharing unit is specifically a series resistor or an active current sharing integrated circuit.

4. The electronic paper display device according to claim 3, wherein The dynamic adjustment instruction is specifically a resistance value adjustment instruction or a parameter control instruction of the active current sharing integrated circuit.

5. The electronic paper display device according to claim 1, wherein The driving control module specifically includes: A driving unit, electrically connecting the current distribution port of the driving unit to the output end of the current sharing circuit module through a second conductive trace; A time-sharing driving logic unit, electrically connected to each independent electrode block of the common electrode cutting module through a third conductive trace.

6. The electronic paper display device according to claim 1, wherein It further includes: A trace layout module, integrated on the thin film transistor substrate side of the electronic paper module, including a symmetrically distributed AC common electrode trace network, and the AC common electrode trace network is electrically connected to the power output end of the driving control module through a third conductive trace to provide a charging and discharging voltage for the common electrode cutting module.

7. The electronic paper display device according to claim 6, wherein The AC common electrode trace network is insulated from the source signal line and the gate signal line of the electronic paper module in different layers.

8. The electronic paper display device according to claim 1, wherein The preset time-sharing sequence is specifically to preferentially activate the independent electrode blocks at the edge when reaching a preset temperature range.

9. The electronic paper display device according to claim 1, characterized in that, The specific preset time-sharing sequence is to output charge and discharge pulses sequentially from the central independent electrode block to the peripheral independent electrode blocks, with the pulse interval between adjacent independent electrode blocks .

10. An electronic paper driving method, characterized in that, Applied to the electronic paper display device according to any one of claims 1-9, the method includes: Cutting the whole-surface common electrode on the color filter substrate side of the electronic paper module into N independent electrode blocks; Configuring a current sharing circuit for each independent electrode block, and dynamically adjusting the charging and discharging currents of each branch through a series resistor or an active current sharing integrated circuit; Receiving the balanced current signal output by the current sharing circuit module, and sending a dynamic adjustment instruction to the current sharing circuit module through a control signal line; Outputting charging and discharging pulses to each independent electrode block in a preset time-sharing sequence in turn, so as to reduce the instantaneous current peak and coordinate the voltage switching of each independent electrode block; Real-time collecting the branch current data corresponding to each independent electrode block, and feeding back the branch current data to the driving control module to dynamically correct the current sharing circuit parameters or the preset time-sharing sequence.

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