A voltage control system suitable for an arrayed electro-fluidic jet

Abstract

The application discloses a voltage control system suitable for an arrayed electro-fluidic nozzle head, which comprises a nozzle control circuit, a PWM waveform generation circuit, a high-voltage amplification circuit and a high-voltage control circuit. The nozzle control circuit is used for outputting a plurality of groups of high-frequency control signals according to a required printing pattern and outputting a control instruction according to ink information carried by a setting instruction inputted from outside. The PWM waveform generation circuit is used for generating a PWM waveform with corresponding parameters according to the control instruction. The high-voltage amplification circuit is used for amplifying the PWM waveform and outputting the amplified PWM waveform as a common high-voltage signal. The high-voltage control circuit is used for receiving the plurality of groups of high-frequency control signals and controlling the common high-voltage signal to be connected with or disconnected from corresponding nozzles, so that high-voltage on-off control of each nozzle in the arrayed electro-fluidic nozzle head is realized, and pattern printing is completed. The application can realize independent control of each nozzle in the arrayed electro-fluidic nozzle head, the number of nozzles in the nozzle head can be large, and the printing efficiency can be effectively improved.

Description

Technical Field

[0001] This patent application belongs to the field of electro-hydraulic inkjet technology, and more specifically, relates to a voltage control system suitable for arrayed electro-hydraulic printheads. Background Technology

[0002] Electrohydraulic inkjet printing technology has attracted widespread attention in the field of micro-nano manufacturing due to its advantages such as additive manufacturing, patterning capability, wide material adaptability, and high efficiency. During the printing process, inks such as TFE and photoresist are precisely sprayed onto the substrate, allowing for the formation of micro-nano scale structures on relatively small substrates as required. Currently, the printing accuracy can be controlled to below 10μm.

[0003] This technology has been successfully applied in fields such as high-definition screens, flexible electronics, and biomedicine. Electrohydraulic inkjet printing technology utilizes an external electric field to generate a driving force far greater than the extrusion force produced by expansion, enabling solution printing across a wider viscosity range (1–10000 cPs). Simultaneously, because the droplets form at the tip of the Taylor cone, the resulting droplet diameter is much smaller than the nozzle diameter, enabling high-resolution structure printing at the micrometer and even nanometer scales, making it a research hotspot in recent years.

[0004] Arrayed electro-hydraulic printheads consist of multiple arrayed nozzles. However, current electro-hydraulic printing technology has the following problems: (1) Traditional arrayed electro-hydraulic printing technology uses centralized control of the entire printhead nozzles, without independent control of each nozzle. In order to print the required pattern, the printhead or substrate is moved mechanically, resulting in low printing efficiency and low ink utilization efficiency, leading to significant waste. (2) Traditional arrayed electro-hydraulic printing does not allow for control of each nozzle, resulting in a limited number of nozzles, typically only a few, which greatly reduces printing efficiency. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this application is to provide a voltage control system suitable for arrayed electro-hydraulic printheads, which aims to solve the problems of traditional electro-hydraulic printing technology being unable to achieve precise control over each nozzle, having a limited number of nozzles, and having low printing efficiency.

[0006] To achieve the above objectives, this application provides a voltage control system suitable for an arrayed current-vacuum nozzle, the arrayed current-vacuum nozzle comprising a plurality of nozzles arranged in an array, the voltage control system comprising:

[0007] The nozzle control circuit is used to configure the working timing parameters of each nozzle in the arrayed electro-hydraulic printhead according to the pattern to be printed, and then output multiple sets of high-frequency control signals according to the working timing parameters. Each set of high-frequency control signals includes two high-frequency control signals. It is also used to output a control command according to the ink information carried by the externally input setting command.

[0008] A PWM waveform generation circuit is used to generate a PWM waveform with corresponding parameters according to the control command. The parameters of the PWM waveform include bias voltage, amplitude voltage, duty cycle and phase.

[0009] The high-voltage amplifier circuit is used to amplify the PWM waveform generated by the PWM waveform generation circuit according to the set parameters and output it as a common high-voltage signal.

[0010] The high-voltage control circuit is used to receive and control the connection and disconnection of the common high-voltage signal and the corresponding nozzle according to each group of high-frequency control signals, thereby realizing the high-voltage on / off control of each nozzle in the arrayed electro-hydraulic nozzle and completing the pattern printing.

[0011] The voltage control system for arrayed electro-hydraulic printheads provided in this application utilizes a nozzle control circuit to output multiple high-frequency control signals to control the connection and disconnection of a common high-voltage signal with the corresponding nozzles. This enables independent control of each nozzle in the printhead, allowing for a large number of nozzles in the printhead. Furthermore, this application configures the working timing parameters of each nozzle in the printhead according to the pattern to be printed, and then controls the start, stop, and duration of the corresponding nozzles based on these parameters to achieve the printing of the desired pattern. Compared with the traditional method of printing the desired pattern by mechanically moving the printhead or substrate, this method can effectively improve printing efficiency.

[0012] As a further preferred embodiment, the bias voltage and amplitude voltage of the PWM waveform, as well as the amplification factor of the high-voltage amplifier circuit, are set accordingly based on the peak voltage required for ink ejection and the voltage required for critical ink ejection in the ink information, and the duty cycle and phase of the PWM waveform are set accordingly based on the properties of the ink.

[0013] As a further preferred embodiment, the high-voltage control circuit employs multiple gating circuits, each gating circuit including a half-bridge circuit and isolated gate driver chips U2 and U3;

[0014] The input terminals of the isolated gate driver chips U2 and U3 respectively receive two high-frequency control signals from a set of high-frequency control signals. The output terminals of the isolated gate driver chips U2 and U3 are respectively connected to the gate of the upper transistor and the gate of the lower transistor in the half-bridge circuit. The drain of the upper transistor is connected to the output terminal of the high-voltage amplifier circuit. The source of the upper transistor and the drain of the lower transistor are respectively connected to a nozzle in the arrayed current fluid nozzle. The source of the lower transistor is grounded. Both the upper transistor and the lower transistor are high-voltage MOS transistors.

[0015] As a further preferred embodiment, the nozzle control circuit includes a host computer, an MCU controller, and several driver chips;

[0016] The host computer is used to configure the working timing parameters of each nozzle in the arrayed current fluid printhead according to the pattern to be printed; the MCU controller is used to control the driver chip to output multiple sets of high-frequency control signals according to the received working timing parameters of each nozzle, and the MCU controller is also used to output a control command to the PWM waveform generation circuit according to the ink information carried by the externally input setting command.

[0017] As a further preferred embodiment, the MCU controller communicates with the host computer via a PHY chip and an RJ45 interface.

[0018] As a further preferred embodiment, the communication rate of the RJ45 interface is greater than or equal to 100Mb / s, and the on / off control signal delay of the RJ45 interface is less than or equal to 1ms.

[0019] As a further preferred embodiment, the PWM waveform generation circuit employs a signal generator.

[0020] As a further preferred embodiment, the high-voltage amplifier circuit employs a high-voltage amplifier.

[0021] As a further preferred embodiment, the arrayed electrohydrodynamic nozzle is applied in the field of OLED, QLED or MicroLED inkjet printing manufacturing. Attached Figure Description

[0022] Figure 1 This is a schematic block diagram of a voltage control system for an arrayed electro-hydraulic nozzle provided in one embodiment of this application;

[0023] Figure 2 This is a schematic block diagram of a voltage control system for an arrayed electro-hydraulic nozzle provided in another embodiment of this application;

[0024] Figure 3 This is a chip diagram of a driver chip provided in one embodiment of this application;

[0025] Figure 4 This is a circuit diagram of a high-voltage control circuit provided in one embodiment of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0027] It should be understood that, in the description of this application, the term "several" means at least one, such as one, two, etc., unless otherwise expressly and specifically defined; the term "multiple" means two or more, unless otherwise expressly and specifically defined; the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order of objects; the term "and / or" includes any and all combinations of one or more of the related listed items.

[0028] Furthermore, throughout this specification, references to "an embodiment"; "an embodiment," "an example," or similar language indicate that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of this application. Therefore, the appearance of the phrase "in one embodiment;" throughout this specification, and similar language, may, but not necessarily, refer to the same embodiment.

[0029] To address the limitations of traditional arrayed electrochemical inkjet printing technology, such as the inability to achieve precise control over each nozzle, the limited number of nozzles, and low printing efficiency, this application provides a voltage control system for arrayed electrochemical printheads. This system is applicable to inkjet printing manufacturing fields such as OLED, QLED, and MicroLED. Figure 1 and 2 As shown, the control system mainly includes a nozzle control circuit 100, a PWM waveform generation circuit 200, a high-voltage amplifier circuit 300, and a high-voltage control circuit 400.

[0030] The nozzle control circuit 100 configures the working timing parameters of each nozzle in the arrayed electrostatic printhead according to the desired printing pattern, i.e., when each nozzle starts printing, when it stops printing, and the duration of its operation. Then, based on these working timing parameters, it outputs multiple sets of high-frequency control signals. Each set of high-frequency control signals includes two high-frequency control signals, and each set is used to control the working state of one nozzle. Furthermore, the nozzle control circuit 100 also outputs a control command based on ink information carried by an externally input setting instruction.

[0031] Specifically, the nozzle control circuit 100 may employ a host computer, an MCU controller, and several driver chips. Preferably, the MCU controller communicates with the host computer via a PHY chip and an RJ45 interface. Preferably, to meet communication speed requirements, the communication rate of the RJ45 interface is greater than or equal to 100Mb / s, and the on / off control signal delay of the RJ45 interface is less than or equal to 1ms.

[0032] In this embodiment, the host computer determines the operating timing parameters of each nozzle in the arrayed current fluid printhead based on the desired printed pattern using a pattern recognition algorithm commonly used in the art, and sends these parameters to the MCU controller. The MCU controller, based on the received parameters, controls the output terminals of each driver chip to output corresponding high-frequency control signals. Each pair of high-frequency control signals output by the driver chip is used to control the operating state of one nozzle. Furthermore, the MCU controller also outputs a control command to the backend PWM waveform generation circuit based on the ink information carried by the externally input setting command.

[0033] Considering the high efficiency and high resolution requirements of inkjet printing manufacturing fields such as OLED, QLED, and MicroLED, high resolution and high efficiency necessitate high-frequency and sufficiently numerous control signals for controlling the nozzles. Therefore, the driver chip provided in this embodiment is preferably a driver chip with 16 output terminals and a frequency of several kilohertz.

[0034] Figure 3 This is a chip diagram of a driver chip provided in one embodiment of this application, such as... Figure 3 As shown, the driver chip U1 has 16 high-frequency signal output terminals (KZXH0-KZXH15). Capacitors C1 and C2 are connected in parallel to the VDD terminal of the driver chip U1. Capacitors C1 and C2 are used to filter the power supply of the chip to ensure stable operation. The CLK terminal of the driver chip U1 is the chip clock pin. A stable clock is provided from the outside to ensure stable operation of the chip. The OE terminal of the driver chip U1 is the chip enable pin, which is active low. The I2C_SDA and I2C_SCL of the driver chip U1 are pulled up through resistors R8 and R9 to ensure normal I2C communication.

[0035] In addition, this application has found through research that: (1) within a printing cycle, the peak voltage can ensure the ink is ejected from the nozzle, and the peak voltage required for the nozzle to complete different ink ejections varies; (2) within a printing cycle, during the non-peak voltage period (duty time), the ink at the nozzle is kept in a critical ejection state to ensure that it can be ejected immediately at the next peak voltage, thereby ensuring the consistency of the overall ejected droplet volume. Thus, in the printing manufacturing fields of large-area, high-efficiency, and high-precision OLED, QLED, MicroLED, etc., it can ensure that the printing accuracy with an error of less than 10um is achieved within the printing size at the μm level.

[0036] Therefore, the PWM waveform generation circuit 200 provided in this embodiment is used to generate a PWM waveform with corresponding parameters according to the control instructions output by the MCU controller. These parameters include bias voltage, amplitude voltage, frequency, duty cycle, and phase.

[0037] Since the PWM waveform generated by the PWM waveform generation circuit 200 is low voltage and cannot be directly supplied to the nozzle, the voltage control system provided in this application also needs to include a high voltage amplifier circuit 300, which amplifies the PWM waveform generated by the PWM waveform generation circuit according to the set parameters and outputs it as a common high voltage signal.

[0038] In this embodiment, the bias voltage and amplitude voltage in the PWM waveform generated by the PWM waveform generation circuit 200, as well as the amplification factor of the high-voltage amplifier circuit 300, can be set according to the peak voltage required for ink ejection and the voltage required for critical ink ejection. The frequency in the PWM waveform generated by the PWM waveform generation circuit 200 can be set according to the efficiency required for printing. The duty cycle and phase in the PWM waveform generated by the PWM waveform generation circuit 200 can be set according to the properties of the ink required for printing.

[0039] For example, if the peak voltage required for a certain type of ink ejection is 1100V and the critical ejection voltage required for the ink is 900V, then the bias voltage of the PWM waveform generated by the PWM waveform generation circuit 200 can be set to 1V, the amplitude voltage can be set to 0.1V, and the amplification factor of the high-voltage amplifier circuit can be set to 1000 times, so that the common high-voltage signal output by the high-voltage amplifier circuit is a standard PWM waveform with a minimum voltage of 900V and a maximum voltage of 1100V, which meets the ejection requirements of the ink.

[0040] Specifically, the PWM waveform generation circuit provided in this embodiment can be a signal generator; the high voltage amplifier circuit 300 provided in this embodiment can be a high voltage amplifier.

[0041] The high-voltage control circuit 400 is used to receive and control the common high-voltage signal output by the high-voltage amplifier circuit 300 and the corresponding nozzles to turn on and off according to the high-frequency control signals of each group, thereby realizing the high-voltage on / off control of each nozzle in the arrayed electro-hydraulic printhead and completing the printing.

[0042] Specifically, the high-voltage control circuit 400 provided in this embodiment employs multiple gating circuits, each of which includes a half-bridge circuit and isolated gate driver chips U2 and U3.

[0043] like Figure 4As shown, in each selection circuit, the input terminals of the isolated gate driver chips U2 and U3 receive two high-frequency control signals from a set of high-frequency control signals. The output terminals of the isolated gate driver chips U2 and U3 are connected to the gates of the upper and lower transistors in the half-bridge circuit. The drain of the upper transistor is connected to the output terminal of the high-voltage amplifier circuit (i.e., the output terminal of the common high-voltage signal). The source of the upper transistor and the drain of the lower transistor correspond to one of the nozzles in the arrayed current fluid nozzle (corresponding to...). Figure 4 The lower transistor is connected to CH1_HV, and its source is grounded.

[0044] It should be noted that, since the half-bridge circuit provided in this embodiment transmits high-voltage signals, both the upper and lower transistors used in the half-bridge circuit must be high-voltage MOSFETs.

[0045] The working principle of the selection circuit provided in this embodiment is as follows: the isolation gate driver chips U2 and U3 are used to ensure that the subsequent high voltage circuit (high voltage amplifier circuit) is isolated from the front-end low voltage circuit (nozzle control circuit), and also to ensure that the subsequent high voltage circuit is turned on and off quickly; Figure 4 Capacitors C3 and C4, and capacitors C5 and C6 are used to filter the power supply across the isolated gate driver chips U2 and U3, respectively, to ensure stable operation. Resistors R13 and R14, R11 and R12, R17 and R18, and R15 and R16 are connected in series at the input and output terminals of the isolated gate driver chips U2 and U3, respectively, to adjust the input and output waveforms of the isolated gate driver chips U2 and U3, ensuring that the voltage waveform requirements of arrayed current fluid inkjet printing are met. High-frequency control signals KZXH0 and KZXH1 are... Figure 2 The high-voltage signal VCC_HV is generated by the driver chip. By controlling whether it is generated or not, it works with the upper transistor Q1 and the lower transistor Q2 at the back end to realize the switching of the common high-voltage signal VCC_HV on the corresponding nozzle, which acts as a high-voltage switch and thus determines the working state of the corresponding nozzle. The resistor R10 mainly serves as a current limiter to protect the high-voltage MOSFET.

[0046] The working process of the voltage control system provided in this embodiment is as follows:

[0047] (1) The host computer configures the working timing parameters of each nozzle in the arrayed electro-hydraulic printhead according to the characteristics of the pattern to be printed, and determines when each nozzle starts spraying, when it stops spraying, and the working duration, etc.

[0048] (2) The MCU controller is used to receive and control the drive chip to output a high-frequency control signal to the high-voltage control circuit according to the working timing parameters of each nozzle output by the host computer; at the same time, it outputs a control command to the PWM waveform generation circuit according to the ink information carried by the external input setting command.

[0049] (3) The signal generator is used to generate a PWM waveform with corresponding parameters according to the control instructions output by the MCU controller; the high voltage amplifier receives the PWM waveform generated by the signal generator, amplifies the voltage according to the set parameters, and outputs it as a common high voltage signal.

[0050] (4) Each selection circuit in the high voltage control circuit is used to receive and control the connection and disconnection of the common high voltage signal and the corresponding nozzle according to each group of high frequency control signals, thereby realizing the high voltage on / off control of each nozzle in the arrayed electro-hydraulic nozzle and completing the pattern printing.

[0051] The voltage control system for arrayed electrochemical printheads provided in this embodiment utilizes a nozzle control circuit to output multiple high-frequency control signals to control the connection and disconnection of a common high-voltage signal with the corresponding nozzles. This enables independent control of each nozzle in the printhead, allowing for a large number of nozzles in the printhead. In addition, this embodiment configures the working timing parameters of each nozzle in the printhead according to the pattern to be printed, and then controls the start, stop, and duration of the corresponding nozzles according to these parameters to achieve the printing of the desired pattern. Compared with the traditional method of printing the desired pattern by mechanically moving the printhead or substrate, this method can effectively improve printing efficiency.

[0052] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A voltage control system suitable for an arrayed electrothermal nozzle, the arrayed electrothermal nozzle comprising a plurality of nozzles arranged in an array, characterized in that, The voltage control system includes: The nozzle control circuit is used to configure the working timing parameters of each nozzle in the arrayed electro-hydraulic printhead according to the pattern to be printed, and then output multiple sets of high-frequency control signals according to the working timing parameters. Each set of high-frequency control signals includes two high-frequency control signals. It is also used to output a control command according to the ink information carried by the externally input setting command. A PWM waveform generation circuit is used to generate a PWM waveform with corresponding parameters according to the control command. The parameters of the PWM waveform include bias voltage, amplitude voltage, duty cycle and phase. The high-voltage amplifier circuit is used to amplify the PWM waveform generated by the PWM waveform generation circuit according to the set parameters and output it as a common high-voltage signal. The high-voltage control circuit is used to receive and control the connection and disconnection of the common high-voltage signal and the corresponding nozzle according to each group of high-frequency control signals, thereby realizing the high-voltage on / off control of each nozzle in the arrayed electro-hydraulic nozzle and completing the pattern printing. The bias voltage and amplitude voltage of the PWM waveform, as well as the amplification factor of the high-voltage amplifier circuit, are set accordingly based on the peak voltage required for ink ejection and the voltage required for critical ink ejection in the ink information. The duty cycle and phase of the PWM waveform are set accordingly based on the properties of the ink.

2. The voltage control system for arrayed electro-hydraulic nozzles as described in claim 1, characterized in that, The high-voltage control circuit employs multiple gating circuits, each of which includes a half-bridge circuit and isolated gate driver chips U2 and U3. The input terminals of the isolated gate driver chips U2 and U3 respectively receive two high-frequency control signals from a set of high-frequency control signals. The output terminals of the isolated gate driver chips U2 and U3 are respectively connected to the gate of the upper transistor and the gate of the lower transistor in the half-bridge circuit. The drain of the upper transistor is connected to the output terminal of the high-voltage amplifier circuit. The source of the upper transistor and the drain of the lower transistor are respectively connected to a nozzle in the arrayed current fluid nozzle. The source of the lower transistor is grounded. Both the upper transistor and the lower transistor are high-voltage MOS transistors.

3. The voltage control system for arrayed electro-hydraulic nozzles as described in any one of claims 1 to 2, characterized in that, The nozzle control circuit includes a host computer, an MCU controller, and several driver chips; The host computer is used to configure the working timing parameters of each nozzle in the arrayed current fluid printhead according to the pattern to be printed; the MCU controller is used to control the driver chip to output multiple sets of high-frequency control signals according to the received working timing parameters of each nozzle, and the MCU controller is also used to output a control command to the PWM waveform generation circuit according to the ink information carried by the externally input setting command.

4. The voltage control system for arrayed electro-hydraulic nozzles as described in claim 3, characterized in that, The MCU controller communicates with the host computer through a PHY chip and an RJ45 interface.

5. The voltage control system for arrayed electro-hydraulic nozzles as described in claim 4, characterized in that, The communication rate of the RJ45 interface is greater than or equal to 100 Mb / s, and the on / off control signal delay of the RJ45 interface is less than or equal to 1ms.

6. The voltage control system for arrayed electro-hydraulic nozzles as described in claim 1, characterized in that, The PWM waveform generation circuit uses a signal generator.

7. The voltage control system for arrayed electro-hydraulic nozzles as described in claim 1, characterized in that, The high-voltage amplifier circuit uses a high-voltage amplifier.

8. The voltage control system for arrayed electro-hydraulic nozzles as described in claim 1, characterized in that, The arrayed electrohydrodynamic printhead is used in the printing and manufacturing of OLED, QLED, or MicroLED.

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