JP2006061806A - Method of drying droplet-discharging head, droplet-discharging apparatus, method of manufacturing device and the device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of driving a droplet-discharging head permitting raising of the droplet-discharging frequency and being capable of discharging even a liquid of high viscosity precisely and stably. <P>SOLUTION: The head has a cavity storing a specified liquid, a pressure-generating element generating a pressure corresponding to applied driving signals within the cavity and a nozzle opening discharging as droplets a liquid pressurized by the pressure-generating element. Driving signals including a group of wave forms comprising two or more forms w1 to w6 are applied to a piezoelectric element in close synchronization with the vibration frequency of the meniscus of the liquid at the nozzle opening. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a driving method and a droplet discharge apparatus for a droplet discharge head for discharging a predetermined liquid as droplets, a device manufacturing method using the driving method or apparatus, and a device manufactured using the manufacturing method About.

  A droplet discharge head provided in the droplet discharge apparatus includes a pressure generation chamber that stores a predetermined liquid, a pressure generation element such as a piezo (PZT) element that pressurizes the pressure generation chamber, and a nozzle opening that communicates with the pressure generation chamber. It is comprised including. In the droplet discharge head having such a configuration, a minute amount of liquid is discharged as a droplet from the nozzle opening by applying a driving signal to the pressure generating element to pressurize the liquid in the pressure generating chamber.

The drive signal applied to the pressure generating element includes, for example, a lead-in portion that increases the volume of the pressure generating chamber to generate a negative pressure in the pressure generating chamber, a holding portion that holds the increased volume of the pressure generating chamber for a certain time, and a pressure An extruding unit that pressurizes the pressure generating chamber by rapidly reducing the volume of the generating chamber, and a damping unit that suppresses vibration of the liquid level (meniscus) of the liquid in the nozzle opening. By continuously applying such a drive signal to the pressure generating element, a predetermined amount of liquid droplets are continuously ejected from the nozzle opening. For the conventional driving method of the droplet discharge head, see, for example, Patent Documents 1 and 2 below.
JP 2004-001479 A JP 2001-047619 A

  By the way, in recent years, the above-described droplet discharge device is used for manufacturing various devices having fine patterns such as color filters, microlens arrays, and the like used in display devices such as liquid crystal display devices in addition to image forming devices such as printers. It has been used. For example, in a color filter manufacturing process, a droplet discharge device is used to discharge a predetermined amount of each color ink of red (R), green (G), and blue (B) to a predetermined position. . In order to improve productivity, a droplet discharge device used for such applications is desired to improve throughput (the number of devices that can be manufactured per unit time).

  As described above, the conventional droplet discharge device drives the pressure generating element by continuously applying the driving signal having the drawing part, the holding part, the pushing part, and the vibration damping part to the pressure generating element. Here, the vibration control unit provided in the drive signal is provided to suppress the meniscus vibration of the nozzle opening after the discharge of one droplet and before the discharge of the next droplet. This is extremely important for stably and continuously discharging droplets from the nozzle openings.

  However, when the pressure generating element is driven by the drive signal having the suppression unit, it is impossible to discharge the liquid droplet until the meniscus vibration of the nozzle opening is suppressed each time the liquid droplet is discharged. For this reason, conventionally, for example, the discharge frequency of ink (viscosity of about 10 mPa · s) used when manufacturing a color filter for a liquid crystal display device has a limit of about 20 kHz. Since the number of droplet discharges per unit time (droplet discharge frequency) greatly affects device productivity, it is desirable to improve the droplet discharge frequency.

  Further, the droplet discharge device is required to stably discharge liquids having various viscosities. In particular, when manufacturing a device, a highly viscous liquid is often used. Furthermore, recent devices are required to have high performance. Taking a color filter as an example, a filter with no color unevenness is required. In order to meet the above requirements, it is necessary to accurately and stably discharge even a liquid having a high viscosity.

  The present invention has been made in view of the above circumstances, and is capable of increasing the discharge frequency of liquid droplets, and capable of accurately and stably discharging even a liquid having a high viscosity. It is an object to provide a driving method and a droplet discharge apparatus, a device manufacturing method using the driving method or apparatus, and a device manufactured using the manufacturing method.

In order to solve the above problems, a method of driving a droplet discharge head according to the present invention includes a cavity that stores a predetermined liquid, a pressure generating element that generates a pressure in the cavity according to an applied drive signal, A method of driving a droplet discharge head having a nozzle opening from which the liquid pressurized by the pressure generating element is discharged as a droplet, wherein the vibration period of the liquid contained in the cavity in the nozzle opening The drive signal is applied to the pressure generating element almost in synchronization with the pressure generating element.
According to the present invention, since the drive signal is applied to the pressure generating element substantially in synchronization with the vibration period of the liquid nozzle opening accommodated in the cavity, the liquid level of the liquid in the nozzle opening ( Without waiting for the vibration of the meniscus to be suppressed, droplets are ejected in synchronization with the vibration of the meniscus. Thereby, the discharge frequency of droplets can be increased.
Further, in the driving method of the droplet discharge head according to the present invention, the driving signal includes a waveform group including at least two continuous waveforms, and the waveform group is generated in the pressure generation substantially in synchronization with the vibration cycle of the liquid. It is characterized by being applied to the element.
According to the present invention, since a waveform group consisting of at least two continuous waveforms is applied to the pressure generating element in synchronization with the vibration cycle of the liquid, pressurization and depressurization according to the waveform included in the waveform group are applied in the cavity. A droplet is discharged at For this reason, for example, if the waveform is changed according to the viscosity of the liquid, liquids having various viscosities can be easily discharged as droplets. In particular, even a liquid having a high viscosity can be accurately and stably discharged.
Further, in the driving method of the droplet discharge head of the present invention, the reference level of the waveform is discharged from the nozzle opening when the first waveform included in the waveform group is applied to the pressure generating element. The distance between the droplet and the droplet discharged from the nozzle opening when the second waveform included in the waveform group is applied to the pressure generating element is set to be substantially the minimum. It is characterized by.
According to this invention, when the first waveform included in the waveform group is applied to the pressure generating element, the previous droplet ejected from the nozzle opening and the second waveform included in the waveform group are applied to the pressure generating element. The reference level for the waveform is set so that the distance from the nozzle opening to the droplet ejected from the nozzle opening is almost minimized. For example, when the first waveform is applied to the pressure generating element, a large amount of droplets are generated. It is possible to prevent a situation in which a small amount of liquid droplets are ejected at a low speed when ejected at a high speed and the second waveform is applied to the pressure generating element. As a result, the first ejected droplet and the next ejected droplet are separated from each other, and an extremely fine droplet (mist) can be prevented from being formed therebetween.
Further, in the driving method of the droplet discharge head of the present invention, the waveform is a first waveform part that increases the volume of the cavity and generates a negative pressure in the cavity, and the driving of the pressure generating element is stopped for a certain time. The present invention preferably comprises a second corrugated portion, a third corrugated portion that pressurizes the cavity by rapidly decreasing the volume of the cavity, and a fourth corrugated portion that stops driving the pressure generating element for a predetermined time. According to the above, since the waveform included in the waveform group is composed of a total of four waveform portions, the first waveform portion to the fourth waveform portion, the waveform shape can be freely changed according to, for example, the viscosity of the liquid Can do. For example, for a high-viscosity liquid, the cavity can be filled with a sufficiently high-viscosity liquid by forming the first corrugated portion into a shape that rapidly generates a negative pressure in the cavity. In addition, by forming the third corrugated portion into a shape that rapidly pressurizes the inside of the cavity, a large amount of liquid can be discharged at a time.
In the droplet discharge head driving method of the present invention, the drive signal includes a suppression waveform that suppresses the vibration of the liquid in the nozzle opening.
According to the present invention, since the drive signal includes the suppression waveform that suppresses the vibration of the liquid at the nozzle opening, the above-described waveform group is applied to the pressure generating element and continuously discharged. However, the vibration of the liquid at the nozzle opening can be suppressed.
In the method for driving a droplet discharge head according to the present invention, the time of the first waveform portion and the third waveform portion is set to a time substantially equal to the natural vibration period of the pressure generating element. Yes.
According to the present invention, the time of the first corrugated portion that generates negative pressure in the cavity and the third corrugated portion that pressurizes the cavity is set to a time substantially equal to the natural vibration period of the pressure generating element. It is possible to prevent a situation in which the generation element resonates and vibration is continued without applying a drive signal. Such a resonance state is maximized when, for example, the time of the first waveform portion or the third waveform portion is set to half the natural vibration period of the pressure generating element.
Further, in the driving method of the droplet discharge head of the present invention, the time of the second waveform portion and the fourth waveform portion is discharged from the nozzle opening when the waveform group is applied to the pressure generating element. It is characterized in that it is set so that the weight variation of each droplet is minimized.
According to the present invention, when the time of the second waveform portion and the fourth waveform portion is applied to the pressure generating element, the weight variation of each droplet discharged from the nozzle opening is minimized. Since it is set, the weight of the liquid droplets discharged from the nozzle openings is made uniform.
In the method of driving a droplet discharge head according to the present invention, after the waveform group is applied to the pressure generating element, the volume of the cavity is increased over a time substantially equal to the natural vibration period of the pressure generating element. The terminal waveform for generating a negative pressure in the cavity is applied to the pressure generating element.
According to the present invention, after the waveform group is applied to the pressure generating element and droplets are continuously ejected, the volume of the cavity is increased over a time substantially equal to the natural vibration period of the pressure generating element to Since a terminal waveform for generating a negative pressure is applied to the pressure generating element, the last ejected liquid droplet is drawn into the cavity from the nozzle opening in a short time. As a result, it is possible to prevent the generation of minute droplets (satellite) separated from the tail portion of the droplet and the last discharged droplet, and as a result, it is possible to prevent droplet discharge failure and While being able to discharge stably, adhesion of the droplet to positions other than the position where a droplet should be taken out can be prevented.
Also, in the driving method of the droplet discharge head of the present invention, after applying the waveform group to the pressure generating element, the volume of the cavity is set at least for a time substantially equal to the vibration period of the liquid in the nozzle opening. A terminal waveform that increases and generates a negative pressure in the cavity is applied to the pressure generating element.
According to the present invention, after the waveform group is applied to the pressure generating element and droplets are continuously ejected, the cavity volume is increased at least for a time substantially equal to the liquid oscillation period in the nozzle opening to Since the terminal waveform for generating a negative pressure is applied to the pressure generating element, the finally ejected liquid droplet is drawn into the cavity from the nozzle opening for a long time. Accordingly, even when a liquid having high elasticity or a liquid having high viscosity is ejected from the nozzle opening, the tail is cut naturally even if a long tail is pulled. Therefore, the nozzle opening is contaminated by the cut tail, resulting in ejection failure. Such a situation does not occur and droplets can be discharged stably.
In the method of driving a droplet discharge head according to the present invention, at least one waveform included in the waveform group is different in shape from other waveforms.
According to the present invention, since the shape of at least one waveform included in the waveform group is different from the shape of other waveforms, for example, the total weight of all droplets ejected from the nozzle openings can be finely adjusted. it can.
Here, it is desirable that at least one waveform included in the waveform group is different from the other waveforms in at least one of time and peak value of at least one of the first waveform portion to the fourth waveform portion.
The waveforms having different shapes are preferably the first waveform or the last waveform included in the waveform group.
The droplet ejection head driving method of the present invention is characterized in that a waveform having a different shape and a waveform having the same shape as the other waveform can be selected alternatively.
According to the present invention, since a waveform having a different shape and a waveform having the same shape as another waveform can be selected, fine adjustment of the total weight of all droplets ejected from the nozzle opening is facilitated. It can be carried out.
In addition, the driving method of the droplet discharge head according to the present invention is characterized in that the waveforms included in the waveform group have different shapes.
Here, each of the waveforms included in the waveform group is preferably a waveform in which the peak value gradually decreases.
According to the present invention, since the waveform included in the waveform group is a waveform in which the crest value gradually decreases, the ejection speed and the size of the droplet decrease each time a droplet is ejected. This can weaken the impact when the liquid droplets land and can prevent the liquid droplets from adhering to a position other than the position where the liquid droplets should be ejected.
In order to solve the above problems, a droplet discharge device according to the present invention includes a cavity for storing a predetermined liquid, a pressure generating element for generating a pressure in the cavity according to an applied drive signal, and the pressure generation A liquid droplet ejection apparatus comprising a liquid droplet ejection head having a nozzle opening through which the liquid pressurized by an element is ejected as a liquid droplet, wherein a vibration period of the liquid contained in the cavity in the nozzle opening And a drive section for applying the drive signal to the pressure generating element in synchronization with the pressure generating element.
According to the present invention, since the drive signal is applied to the pressure generating element substantially in synchronization with the vibration cycle of the liquid nozzle opening accommodated in the cavity, the liquid level of the liquid at the nozzle opening ( Without waiting for the vibration of the meniscus to be suppressed, droplets are ejected in synchronization with the vibration of the meniscus. Thereby, the discharge frequency of droplets can be increased.
Further, the device manufacturing method of the present invention is a device manufacturing method including a workpiece having a pattern having functionality at a predetermined location, and the method for driving the droplet discharge device according to any one of the above, Alternatively, the method includes a discharge step of discharging the predetermined liquid from the nozzle opening provided in the droplet discharge head using the droplet discharge apparatus.
According to the present invention, a predetermined liquid is discharged at a high droplet discharge frequency from a nozzle opening provided in the droplet discharge head using the droplet discharge head driving method or the droplet discharge device described above. Therefore, the device can be manufactured efficiently and the throughput can be improved.
The device of the present invention is manufactured using the above-described device manufacturing method.

  Hereinafter, a droplet ejection head driving method, a droplet ejection apparatus, a device manufacturing method, and a device according to an embodiment of the present invention will be described in detail with reference to the drawings.

[Droplet discharge device]
FIG. 1 is a perspective view showing a schematic configuration of a droplet discharge device according to an embodiment of the present invention. In the following description, if necessary, an XYZ orthogonal coordinate system is set in the drawing, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. In the XYZ orthogonal coordinate system, the XY plane is set to a plane parallel to the horizontal plane, and the Z axis is set to the vertically upward direction. In this embodiment, the movement direction of the discharge head (droplet discharge head) 20 is set to the X direction, and the movement direction of the stage ST is set to the Y direction.

  As shown in FIG. 1, the droplet discharge device IJ of the present embodiment is supported on a base 10, a stage ST that supports a substrate P such as a glass substrate on the base 10, and above the stage ST (+ Z direction), An ejection head 20 that can eject predetermined droplets onto the substrate P is configured. Between the base 10 and the stage ST, a first moving device 12 that supports the stage ST so as to be movable in the Y direction is provided. A second moving device 14 that supports the ejection head 20 so as to be movable in the X direction is provided above the stage ST.

  A tank 16 that stores a solvent (liquid) of liquid droplets discharged from the discharge head 20 via the flow path 18 is connected to the discharge head 20. A capping unit 22 and a cleaning unit 24 are arranged on the base 10. The control device 26 controls each part (for example, the first moving device 12 and the second moving device 14) of the droplet discharge device IJ to control the entire operation of the droplet discharge device IJ.

  The first moving device 12 is installed on the base 10 and is positioned along the Y-axis direction. The first moving device 12 includes, for example, a linear motor, and includes guide rails 12a and 12a, and a slider 12b provided to be movable along the guide rail 12a. The slider 12b of the linear motor type first moving device 12 can be positioned by moving in the Y-axis direction along the guide rail 12a.

The slider 12b includes a motor 12c for rotating around the Z axis (θ _Z ). The motor 12c is, for example, a direct drive motor, and the rotor of the motor 12c is fixed to the stage ST. Thus, by energizing the motor 12c, the rotor and the stage ST can rotate along the _θZ direction to index (rotate index) the stage ST. That is, the first moving device 12 is capable of moving the stage ST in the Y-axis direction and theta _Z direction. The stage ST holds the substrate P and positions it at a predetermined position. The stage ST has a suction holding device (not shown), and the suction holding device operates to suck and hold the substrate P on the stage ST through a suction hole (not shown) provided in the stage ST. To do.

  The second moving device 14 is mounted upright with respect to the base 10 using the support columns 28a and 28a, and is mounted at the rear portion 10a of the base 10. The second moving device 14 is constituted by a linear motor and is supported by a column 28b fixed to the columns 28a and 28a. The second moving device 14 includes a guide rail 14a supported by the column 28b, and a slider 14b supported so as to be movable in the X-axis direction along the guide rail 14a. The slider 14b can be positioned by moving in the X-axis direction along the guide rail 14a. The ejection head 20 is attached to the slider 14b.

  The discharge head 20 has motors 30, 32, 34, and 36 as swing positioning devices. If the motor 30 is driven, the ejection head 20 can be moved up and down along the Z direction, and the ejection head 20 can be positioned at an arbitrary position in the Z direction. When the motor 32 is driven, the ejection head 20 can be swung along the β direction around the Y axis, and the angle of the ejection head 20 can be adjusted. By driving the motor 34, the ejection head 20 can be swung along the γ direction around the X axis, and the angle of the ejection head 20 can be adjusted. If the motor 36 is driven, the ejection head 20 can be swung along the α direction around the Z axis, and the angle of the ejection head 20 can be adjusted.

  As described above, the ejection head 20 shown in FIG. 1 can move linearly in the Z direction, and can slide along the α direction, β direction, and γ direction to adjust the angle of the slider 14b. It is supported by. The position and posture of the discharge head 20 are accurately controlled by the control device 26 so that the position or posture of the droplet discharge surface 20a with respect to the substrate P on the stage ST side becomes a predetermined position or a predetermined posture. Note that a plurality of nozzle openings for discharging droplets are provided on the droplet discharge surface 20a of the discharge head 20.

  As the droplets ejected from the ejection head 20 described above, an ink containing a coloring material, a dispersion containing a material such as metal fine particles, a hole injection material such as PEDOT: PSS, and an organic EL substance such as a light emitting material are used. Liquid droplets containing various materials such as high-viscosity functional liquids such as liquid solutions and liquid materials, functional liquids containing microlens materials, and biopolymer solutions containing proteins and nucleic acids are used. The

  Here, the configuration of the ejection head 20 will be described. FIG. 2 is an exploded perspective view of the ejection head 20, and FIG. 3 is a perspective view showing a part of the main part of the ejection head 20. The discharge head 20 shown in FIG. 2 includes a nozzle plate 110, a pressure chamber substrate 120, a vibration plate 130, and a housing 140. As shown in FIG. 2, the pressure chamber substrate 120 includes a cavity 121, a side wall 122, a reservoir 123, and a supply port 124. The cavity 121 is a pressure chamber and is formed by etching a substrate such as silicon. The side wall 122 is configured to partition the cavities 121, and the reservoir 123 is configured as a common flow path that can supply liquid when the cavities 121 are filled with liquid. The supply port 124 is configured to be able to introduce liquid into each cavity 121.

  Further, as shown in FIG. 3, the diaphragm 130 is configured to be bonded to one surface of the pressure chamber substrate 120. The diaphragm 130 is provided with a piezoelectric element 150 as a force generation element. The piezoelectric element 150 is a ferroelectric crystal having a perovskite structure, and is formed on the diaphragm 130 in a predetermined shape. The piezoelectric element 150 is configured to be capable of causing a volume change in response to a drive signal supplied from the control device 26. The nozzle plate 110 is bonded to the pressure chamber substrate 120 so that the nozzle openings 111 are arranged at positions corresponding to the plurality of cavities (pressure chambers) 121 provided in the pressure chamber substrate 120. The pressure chamber substrate 120 to which the nozzle plate 110 is bonded is further fitted in a housing 140 to form the droplet discharge head 20 as shown in FIG.

  In order to eject droplets from the ejection head 20, first, the control device 26 supplies a drive signal for ejecting the droplets to the ejection head 20. The liquid flows into the cavity 121 of the ejection head 20, and when a drive signal is supplied to the ejection head 20, the piezoelectric element 150 provided in the ejection head 20 changes in volume according to the drive signal. This volume change deforms the diaphragm 130 and changes the volume of the cavity 121. As a result, a droplet is ejected from the nozzle opening 111 of the cavity 121. The liquid reduced by the discharge is newly supplied from the tank to the cavity 121 from which the droplet has been discharged.

  Returning to FIG. 1, the second moving device 14 can selectively position the discharge head 20 above the cleaning unit 24 or the capping unit 22 by moving the discharge head 20 in the X-axis direction. That is, even during the device manufacturing operation, for example, if the ejection head 20 is moved onto the cleaning unit 24, the ejection head 20 can be cleaned. Further, if the ejection head 20 is moved onto the capping unit 22, capping is performed on the droplet ejection surface 20 a of the ejection head 20, the droplet is filled into the cavity 121, or ejection due to clogging of the nozzle opening 111 or the like. It becomes possible to recover defects.

  That is, the cleaning unit 24 and the capping unit 22 are arranged on the rear portion 10a side on the base 10 and directly below the moving path of the ejection head 20 and separated from the stage ST. Since the loading and unloading operations of the substrate P with respect to the stage ST are performed on the front portion 10b side of the base 10, the cleaning unit 24 or the capping unit 22 does not hinder the operation.

  The cleaning unit 24 can perform cleaning of the nozzle openings 111 and the like of the ejection head 20 regularly or at any time during the device manufacturing process or during standby. The capping unit 22 performs capping on the droplet discharge surface 20a during standby when the device is not manufactured so as not to dry the droplet discharge surface 20a of the discharge head 20, or is used when filling the cavity 121 with droplets. Also, the ejection head 20 in which ejection failure has occurred is recovered. 2 and 3, only one row of the plurality of nozzle openings 111 is shown for simplicity of explanation, but the nozzle openings 111 may be arranged in a plurality of rows. good.

  Next, the electrical functional configuration of the droplet discharge device IJ of this embodiment will be described. FIG. 4 is a block diagram showing an electrical functional configuration of the droplet discharge device according to the embodiment of the present invention. In FIG. 4, blocks corresponding to the members shown in FIGS. 1 to 3 are denoted by the same reference numerals. As shown in FIG. 4, the electrical configuration for controlling the droplet discharge device IJ includes a control computer 50, a control device 26, and a drive circuit 60.

  The control computer 50 includes, for example, an internal storage device such as a CPU (Central Processing Unit), a RAM (Random Access Memory) and a ROM (Read Only Memory), an external storage device such as a hard disk and a CD-ROM, and a liquid crystal display device or CRT (CRT). A control signal for controlling the operation of the droplet discharge device IJ is output in accordance with a program stored in a ROM or a hard disk. The control computer 50 is connected to the control device 26 provided in the droplet discharge device IJ shown in FIG. 1 using, for example, a cable.

  The control device 26 includes an interface 51 that receives ejection position information and ejection conditions from the control computer 50, a DRAM (Dynamic RAM) and an SRAM (Static RAM), a RAM 52 that records various data, and various data processing. It includes a ROM 53 that records routines for execution, a control unit 54 including a CPU, an oscillation circuit 55, a drive signal generation unit 56 that generates a drive signal COM to be supplied to the drive circuit 60, and an interface 57. It is configured.

  Next, a basic operation when the control device 26 having the above-described configuration discharges droplets will be described. When discharge position information, discharge conditions, and the like are sent from the control computer 50, these pieces of information are stored in a reception buffer 52a provided as a part of the RAM 52 via the interface 51. The ejection position information stored in the reception buffer 52 a is sent to an intermediate buffer 52 b provided as a part of the RAM 52 after command analysis is performed. In the intermediate buffer 52b, intermediate data converted into an intermediate code by the control unit 54 is held, and processing for adding information such as the actual droplet ejection position on the stage ST is executed by the control unit 54.

  Next, the control unit 54 analyzes and decodes each of the intermediate data stored in the intermediate buffer 52b, and then develops and stores the dot pattern data for each intermediate data in the output buffer 52c. When the above processing is completed, dot pattern data corresponding to one scan of the ejection head 20 from one of the N dot pattern data is serially transferred to the drive circuit 60 via the interface 57 as ejection data SI. . The ejection data SI is transferred in synchronization with the clock signal CLK from the oscillation circuit 55. When the transfer of one of the N dot pattern data is completed, the next dot pattern data is transferred in the same manner. In this way, N dot pattern data are sequentially transferred from the output buffer 52 c to the drive circuit 60 via the interface 57. At the same time, drive signals for the first moving device 12 and the second moving device 14 are output via the interface 57.

  A drive signal COM for driving the piezoelectric element 150 provided in the drive circuit 60 is generated by the drive signal generation unit 56 and transferred to the drive circuit 60 via the interface 57. At this time, the controller 54 causes the drive signal generator 56 to generate a drive signal COM for each of N dot pattern data transferred to the drive circuit 60. The drive signal COM is also transferred in synchronization with the clock signal CLK from the oscillation circuit 55. In addition to the ejection data SI, the drive signal COM, and the clock signal CLK, a latch signal LAT described later is output from the interface 27 to the drive circuit 60.

  The drive circuit 60 includes a shift register 61, a latch circuit 62, a level shifter 63, and a switch circuit 64. Although the illustration is simplified in FIG. 4, the piezoelectric element 150 is provided by the number of nozzles formed in the ejection head 20 (for example, 360 (180 × 2 rows)), and a switch circuit A plurality of switch elements (not shown) are provided in 64 corresponding to each piezoelectric element 150.

  The shift register 61 converts the ejection data SI transferred from the control device 26 from serial to parallel. The latch circuit 62 latches the ejection data SI converted in parallel by the shift register 61 when the latch signal LAT is output from the control device 26. The level shifter 63 boosts the ejection data SI output from the latch circuit 62 to a voltage that can drive the switch circuit 64, for example, a predetermined voltage of about several tens of volts.

  The switch circuit 64 controls whether or not to supply the drive signal COM to the piezoelectric element 150 in accordance with the ejection data SI output from the level shifter 63. That is, during the period when the voltage level of the ejection data SI applied to each switch element provided in the switch circuit 64 is “1”, the drive signal COM is applied to the corresponding piezoelectric element 150 and the voltage level of the ejection data SI. During the period when is “0”, the application of the drive signal COM to the corresponding piezoelectric element 150 is cut off. Further, the selection signal SEL from the control unit 54 is supplied to the switch circuit 64, and the waveform of the drive signal COM applied to the piezoelectric element 150 can be selected by this selection signal.

[Basic waveform of drive signal]
Next, the basic waveform of the drive signal COM will be described. FIG. 5 is a diagram illustrating an example of a basic waveform of the drive signal COM. The drive signal COM includes a waveform group composed of a plurality of continuous waveforms (waveform elements). In the following, as shown in FIG. 5A, a case where a total of six waveforms w1 to w6 are included in one waveform group will be described as an example. Each of the waveforms included in the waveform group is a waveform for discharging one droplet from the nozzle opening 111.

  As shown in FIG. 5C, each of the waveforms included in the waveform group increases the volume of the cavity 121 shown in FIGS. 2 and 3 to generate the negative pressure in the cavity 121. (First corrugated portion), holding portions h1, h2,... (Second corrugated portion) that hold the increased volume of the cavity 121 for a certain period of time, and the volume of the cavity 121 is rapidly reduced to pressurize the inside of the cavity 121. (Extruded parts d1, d2,...) (Third corrugated part) and holding parts i1, i2,... (Fourth corrugated part) for holding the reduced volume of the cavity 121 for a certain period of time. In the following description, when the time of each part of the waveform is shown, the symbol “T” is shown along with a code indicating the part. For example, the time of the extrusion part d1 is expressed as “Td1”.

  The pull-in portions c1, c2,... Are portions that increase the voltage of the drive signal COM almost linearly from the intermediate potential Vc or the minimum potential Vb to the maximum potential Vh, and the holding portions h1, h2,. It is the part that keeps time. In addition, the pushing portions d1, d2,... Are portions that decrease the voltage of the drive signal COM almost linearly from the maximum potential Vh to the minimum potential Vb, and the holding portions i1, i2,. It is.

  When one of the waveforms described above is applied to the piezoelectric element 150, the piezoelectric element 150 performs the operation shown in FIG. 6 to eject one droplet. FIG. 6 is a diagram illustrating the operation of the piezoelectric element 150 during droplet discharge. First, for example, when the lead-in part c2 in which the voltage value of the drive signal COM shown in FIG. 5C increases is applied to the piezoelectric element 150, the piezoelectric element 150 is moved to the cavity 121 as shown in FIG. A negative pressure is generated in the cavity 121 by bending in the direction of expanding the volume. As a result, the liquid is supplied from the reservoir 123 to the cavity 121. Further, as shown in the figure, the meniscus is drawn into the nozzle opening 111 by slightly drawing the liquid in the nozzle opening 111 toward the inside of the cavity 121.

  Next, when the holding part h2 following the drawing-in part c2 is applied to the piezoelectric element 150, the volume of the cavity 121 is held in an expanded state while the holding part h2 is supplied. Next, when the pushing portion d2 is applied to the piezoelectric element 150, the piezoelectric element 150 rapidly bends in the direction of contracting the volume of the cavity 121, and positive pressure is generated in the cavity 121. Thereby, as shown in FIG. 6B, the droplet D is ejected from the nozzle opening 111. When the holding part i2 following the pushing part d2 is applied to the piezoelectric element 150, the volume of the cavity 121 is held in a contracted state while the holding part h2 is being supplied, as shown in FIG. The meniscus at the nozzle opening 111 is slightly convex. In this state, the drawing portion c3 having the next waveform is applied, and the same discharging operation is performed. By continuously applying a plurality of waveforms to the piezoelectric element 150, a continuous droplet discharging operation is performed.

  As described above, each of the waveforms forming the waveform group included in the drive signal COM of the present embodiment omits the vibration suppression unit that suppresses the meniscus vibration provided in the waveform included in the conventional drive waveform. . Therefore, when the drive signal COM is applied to the piezoelectric element 150, droplets corresponding to six waveforms included in the waveform group from the nozzle opening 111 are continuous without waiting for the meniscus vibration to be suppressed. Will be discharged.

  The drive signal COM of the present embodiment is provided with a suppression waveform for suppressing vibration (meniscus) of the liquid level in the nozzle opening 111 following the waveform group. In the example shown in FIG. 5B, a suppression waveform w0 is provided following each of the waveform groups G1 and G2. The suppression waveform w0 includes (1) prevention of insufficient supply of liquid from the tank 16 due to continuous discharge of droplets, (2) prevention of overheating of the switch circuit 64 provided in the piezoelectric element 150 and the drive circuit 60, (3 It is provided for the purpose of damping the meniscus for the next droplet discharge. Here, it is provided mainly for the purpose of (3) above.

  The waveform group included in the drive signal COM described above is applied to the piezoelectric element 150 almost in synchronization with the meniscus period in the nozzle opening 111 in order to enable continuous discharge of droplets. That is, the volume of the cavity 121 is expanded with a period of vibration of the meniscus toward the nozzle opening 111 to draw liquid into the cavity 121, and the cavity 121 is contracted with a period of vibration of the meniscus toward the outside of the nozzle opening 111. A droplet is discharged from the opening 111. By performing such control, it is possible to discharge droplets continuously without causing a discharge failure.

  The time Tc1, Tc2,... Of the lead-in portions c1, c2,... For generating a negative pressure in the cavity 121 by increasing the volume of the cavity 121, and the volume of the cavity 121 are rapidly decreased to pressurize the cavity 121. The time Td1, Td2,... Of the extruded portions d1, d2,... Is set to substantially the same time as the natural vibration period Ta of the piezoelectric element 150. This is for preventing residual vibration of the piezoelectric element 150 and preventing variation in the weight of the droplets ejected from the plurality of nozzle openings 111.

Further, in order to adjust the timing of drawing the liquid into the cavity 121 and the timing of discharging the droplet from the nozzle opening 111, the holding portions h1, h2,... And the holding portions i1, i2 that hold the volume of the cavity 121 for a certain period of time. , ... time is adjusted. When the natural period (meniscus oscillation period) of the cavity 121 is Tc, the holding times Th1 to Th6 of the holding parts h1 to h6 of the waveforms w1 to w6 forming the waveform group are expressed by the following formula (1), and the holding part: The holding times Ti1 to Ti6 of i1 to i6 are expressed by the following formula (2). However, the variable n in the following formulas (1) and (2) is an integer satisfying 1 ≦ n ≦ 6.
(3/4) × Tc−Tcn ≦ Thn ≦ (5/4) × Tc−Tcn (1)
(3/4) × Tc−Tdn ≦ Tin ≦ (5/4) × Tc−Tdn (2)

  When the holding times Th1 to Th6 of the holding units h1 to h6 are set to a value close to the value on the left side or the right side of the above formula (1), the discharge efficiency is good and the value is set to a value close to the value (Tc−Tcn). In this case, it becomes difficult to be influenced by variations in the natural period Tc of the plurality of cavities 121. Similarly, when the holding times Ti1 to Ti6 of the holding units i1 to i6 are set to a value close to the value on the left side or the right side of the formula (2), the ejection efficiency is good and the value is close to the value (Tc−Tdn). Is set to be less affected by variations in the natural period Tc of the plurality of cavities 121 provided. The holding times Th1 to Th6 of the holding parts h1 to h6 and the holding times Ti1 to Ti6 of the holding parts i1 to i6 are set as appropriate in consideration of the variation of the natural period Tc of each cavity 121. do it.

  In order to adjust the variation in the discharge amount of the liquid droplets discharged from the nozzle opening 111, first, the time Tc1, Tc2,... Of the drawing portions c1, c2,... And the time Td1, Td2 of the extrusion portions d1, d2,. ,... Are measured in conjunction with each other, and the weight of the droplets discharged from each nozzle opening 111 is measured. And the value when the variation | change_quantity of discharge weight (discharge amount) becomes the minimum is set to time Tc1, Tc2, ... of drawing-in part c1, c2, ... and time Td1, Td2, ... of extrusion part d1, d2, .... . Thereby, the dispersion | variation in the discharge weight between the nozzle openings 111 can be minimized.

  If a plurality of ejection heads 20 are provided, the holding times Th1, Th2,... Of the holding units h1, h2,... And the holding times Ti1, Ti2,. While changing, the weight of the droplet discharged from each nozzle opening 111 is measured, and the value when the change amount of the discharge weight (discharge amount) becomes the minimum is held by the holding times Th1, Th2,. ... and holding times Ti1, Ti2, ... of the holding parts i1, i2, ... are set. Thereby, the variation in the discharge weight between the discharge heads 20 can be minimized.

  Further, when the above-described waveform group is applied to the piezoelectric element 150, the discharge weight of the liquid droplet that is initially discharged may differ depending on the type of liquid. In the case of a liquid having a low viscosity (for example, a liquid having a viscosity of about 5 mPa · s), the liquid droplets discharged first tend to have a high discharge speed and a large amount. For this reason, the waveform for ejecting the second droplet is applied to the piezoelectric element 150 before the meniscus at the nozzle opening 111 has sufficiently returned, and the droplet ejected to the second droplet is slow and small in volume. Tend to be.

  FIG. 7 is a diagram showing a discharge state of droplets discharged from the nozzle opening 111 using the drive signal of the present embodiment, and FIG. 7A shows discharge when there is a difference in speed or the like between discharged droplets. It is a figure which shows a condition, (b) is a figure which shows the discharge condition when there is no difference in speed etc. between discharge droplets. In FIG. 7, D <b> 1 to D <b> 6 indicate six droplets ejected from the nozzle opening 111 when the above-described waveform group is applied to the piezoelectric element 150. In the example shown in FIG. 7, the satellite S is generated after the sixth droplet D6 is discharged.

  When there is a difference in speed between the first droplet D1 and the second droplet D2 ejected first, as shown in FIG. 7A, the droplet D1 and the droplet D2 And a mist-like mist m following the droplet D1 is generated between them. In order to eliminate this situation, the intermediate potential Vc (reference level) of the drive signal COM shown in FIG. 5C is set high, and the liquid is drawn into the cavity 121 by the first drawing portion c1 forming a waveform group. By reducing the amount, it is possible to reduce the difference in speed and discharge amount between the droplet D1 and the droplet D2.

  By performing such adjustment, as shown in FIG. 7B, the distance between the droplet D1 and the droplet D2 can be substantially minimized, and the droplets D1 to D6 are ejected at substantially equal intervals. Can do. Although the set value of the intermediate potential Vc may be arbitrary, for example, when the maximum potential Vh is set to 100% and the minimum potential Vb is expressed as 0%, it is desirable to set the range within a range of about 25 to 60%. Further, when the waveform group described above is applied to the piezoelectric element 150 and a liquid having a low viscosity is ejected, the residual vibration after the last droplet D6 is ejected also increases. When the intermediate potential Vc is increased, the effect of damping the meniscus after ejecting the droplet D6 can be increased, so that the frequency characteristics can be improved.

  In the case of a liquid having a high viscosity (for example, a liquid having a viscosity of about 10 mPa · s), it is desirable to set the intermediate potential Vc to be low (for example, 25% or less). When the intermediate potential Vc is set low, the meniscus vibration at the nozzle opening 111 increases, and the first droplet D1 can be stably ejected. Note that, if the viscosity of the liquid is high, the residual vibration is quickly attenuated.

  By applying the drive waveform COM described above to the piezoelectric element 150, it is possible to continuously discharge droplets without waiting for the meniscus vibration in the nozzle opening 111 to be suppressed each time a droplet is discharged. Can do. Thereby, the discharge frequency of droplets can be increased. For example, although the conventional droplet discharge frequency is about 20 kHz, it can be increased to about 70 kHz by applying the present invention. Moreover, even if it is a liquid with a high viscosity or a liquid with a low viscosity, it can discharge accurately and stably as a droplet.

  Furthermore, by setting the intermediate potential Vc of the drive waveform COM, the speed and the discharge amount of the droplets discharged by each waveform forming the waveform group included in the drive waveform can be adjusted. Generation | occurrence | production of mist etc. can be reduced. For example, when a droplet is ejected using a conventional driving waveform, even if it is a polymer-based liquid that has a tail of 1 mm, the tail can be almost eliminated by using the driving waveform COM of this embodiment. This makes it possible to use liquids that could not be used when the conventional driving waveform was used.

[Modification of drive signal]
FIG. 8 is a diagram illustrating a first modification of the drive signal. As described above, the basic waveform of the drive signal COM includes a waveform group consisting of a plurality of waveforms and a suppression waveform w0 following the waveform group. In the first modification shown in FIG. The difference is that terminal waveforms w11 and w12 are provided to prevent the occurrence of a drop tail and the satellite or mist generated after the discharge of the drop.

  The terminal waveform w11 shown in FIG. 8A is composed of a lead-in part c11, a holding part h11, and an extrusion part d11. The time Tc11 of the lead-in part c11 of the terminal waveform w11 is set to substantially coincide with the natural period Tc of the cavity 121. The holding time Th11 of the holding part h11 is set to about (Tc / 2), and the time Td11 of the pushing part d11 is set to about (2 × Tc).

  When the drive signal COM shown in FIG. 8A is applied to the piezoelectric element 150, while the waveform group is being applied, the operation described with reference to FIG. 5 is performed to eject a droplet. When the application of the waveform w6 forming the waveform group is completed, the lead-in part c11 forming the terminal waveform w11 is applied. As described above, the time Tc11 of the lead-in portion c11 is set to substantially coincide with the natural period Tc of the cavity 121, so that the residual vibration of the meniscus in the nozzle opening 111 after the pull-in is suppressed. Next, after the holding part h11 is applied to the piezoelectric element 150, the extruding part d11 is applied, and the voltage of the drive signal COM is gradually reduced to an intermediate potential (suppressed) over a time twice the natural period Tc of the cavity 121. Return to waveform w0).

  By applying the terminal waveform w11 described above to the piezoelectric element 150, the meniscus in the nozzle opening 111 can be returned to the initial position without being vibrated, so that it is possible to quickly prepare for the discharge of the next droplet. Further, in the drive signal COM shown in FIG. 8A, the liquid near the nozzle opening 111 is largely drawn by the drawing part c11 having the terminal waveform w11 after the discharge of the droplet by the application of the waveform group is completed. Therefore, the occurrence of droplet tails and satellites can be suppressed.

  The terminal waveform w12 shown in FIG. 8B is composed only of the lead-in part c12. The time Tc12 of the lead-in part c12 of the terminal waveform w12 is set to about twice (2 × Tc) the natural period Tc of the cavity 121. The time Tc12 of the lead-in part c12 may be about the natural period Tc of the cavity 121, or about three times the natural period Tc or more. Unlike the termination waveform w11 shown in FIG. 8A, the termination waveform w12 shown in FIG. 8B is a waveform that does not perform vibration suppression.

  When the drive signal COM shown in FIG. 8B is applied to the piezoelectric element 150, while the waveform group is being applied, the operation described with reference to FIG. 5 is performed to eject a droplet. When the application of the waveform w6 forming the waveform group is finished, the lead-in part c12 forming the termination waveform w12 is applied, and the voltage of the drive signal COM gently returns to the intermediate potential (suppression waveform w0). In the case where the liquid contains, for example, a polymer, there is a liquid that does not cut well even when the liquid is discharged from the nozzle opening 111 and has a long tail.

  In such a case, if the tail waveform w11 shown in FIG. 8A is forcibly controlled to cut the tail portion, mist is generated and attached in the vicinity of the nozzle opening 111. Defects may occur. The drive signal COM shown in FIG. 8B is such that the discharged liquid is naturally cut without excessive vibration suppression. By using this drive signal COM, stable ejection can be achieved even for a long time, and the ejection frequency can be increased.

  FIG. 9 is a diagram illustrating a second modification of the drive signal. The drive signal COM shown in FIG. 9 is different in that, among the six waveforms included in the waveform group, the last waveform includes a waveform w7 having a shape different from that of the other waveforms w1 to w5. In this waveform 7, the maximum potential is set lower than the other waveforms w 1 to w 5, and the pushing portion is set shorter than the other waveforms w 1 to w 5 in order to compensate for the drop in the droplet discharge speed. The reason why the waveform w7 having a different shape is included in the waveform group is to adjust the droplet discharge amount. In other words, since the amount of droplets discharged from the plurality of nozzle openings 111 varies, the variation in the amount of droplets discharged from each nozzle opening 111 is reduced by including the adjustment waveform w7. . FIG. 9 shows an example in which the waveform group is followed by the termination waveform w12 shown in FIG. 8B.

  In order to realize the drive signal COM, a selection signal SEL for selecting a waveform forming a waveform group included in the drive signal COM is used. As shown in FIG. 9A, when the selection signal SEL is at the H (high) level from the beginning of the waveform group to the end of the termination waveform w12, the waveforms w1 to w5, w7 and the termination waveform w12 are the piezoelectric element 150. And a total of 6 droplets based on the waveforms w1 to w5 and w7 are ejected from the nozzle opening 111. On the other hand, when the selection signal SEL is at the L (low) level at the timing when the waveform w7 is supplied to the switch circuit 64, the potential (minimum potential) of the holding portion of the waveform w5 is held during that period. Therefore, the waveforms w1 to w5 and the terminal waveform w12 are applied to the piezoelectric element 150, and a total of five droplets based on the waveforms w1 to w5 are ejected from the nozzle opening 111.

  FIG. 9B is a diagram illustrating another example of ejection using the selection signal SEL. Similarly to the case of FIG. 9A, when the selection signal SEL is set to the H level from the beginning of the waveform group to the end of the termination waveform w12, the waveforms w1 to w5, w7 and the termination waveform w12 are applied to the piezoelectric element 150. A total of 6 droplets based on the waveforms w1 to w5 and w7 are ejected from the nozzle opening 111. On the other hand, when the potential of the lead portion of the waveform w7 is set to the H level only from the beginning of the waveform group to the intermediate potential (potential of the suppression waveform w0), the waveforms w1 to w5 are applied to the piezoelectric element 150. , A total of 5 droplets based on the waveforms w1 to w5 are ejected from the nozzle opening 111.

  However, since the potential applied to the piezoelectric element 150 is fixed to the intermediate potential after the potential of the lead-in portion of the waveform w7 becomes the intermediate potential, not only the waveform 7 but also the piezoelectric element 150 of the terminal waveform w12. The presence or absence of application to can be controlled. Conversely, the period from the beginning of the waveform group to the potential of the lead-in portion of the waveform w7 is set to the L level, and the period from when the potential of the lead-in portion of the waveform w7 becomes the intermediate potential to the end of the terminal waveform w12 Is set to H level, only minute (small amount) droplets can be ejected based on the waveform w7.

  FIG. 10 is a diagram illustrating a third modification of the drive signal. The drive signal COM shown in FIG. 9 includes a waveform w7 having a shape different from the other waveforms w1 to w5 as the last waveform among the six waveforms forming the waveform group. The drive signal COM shown in FIG. 10 is different in that it includes a waveform w8 having a shape different from the other waveforms w2 to w6 as the first waveform among the six waveforms forming the waveform group. In the waveform 8, as in the waveform w7 shown in FIG. 9, the maximum potential is set lower than the other waveforms w2 to w6, and the push-out section has another waveform to compensate for the drop in the droplet discharge speed. It is set shorter than w2 to w6.

  When the selection signal SEL is set to the H level from the beginning of the waveform group to the end of the termination waveform w12, the waveforms w8, w2 to w6 and the termination waveform w12 are applied to the piezoelectric element 150, and a total of 6 based on the waveforms w8, w2 to w6. A droplet of the droplet is ejected from the nozzle opening 111. On the other hand, the period from the beginning of the waveform group until the potential of the waveform w2 attains the intermediate potential is set to L level, and the potential of the waveform w2 at the acquisition portion becomes the intermediate potential until the end of the terminal waveform w12. When the period is set to the H level, the waveforms w2 to w6 and the terminal waveform w12 are applied to the piezoelectric element 150, and a total of five droplets based on the waveforms w2 to w6 are ejected from the nozzle opening 111.

  By driving the piezoelectric element 150 using the drive signal COM shown in FIG. 9 or FIG. 10 described above, it is possible to reduce variations in the discharge amount of the droplets discharged from the nozzle openings 111. In FIG. 9, the shape of the last waveform forming the waveform group is different from the other waveforms, and in FIG. 10, the shape of the first waveform forming the waveform group is different from the other waveforms. Any one or more of the waveforms forming the waveform group can be shaped differently from the other waveforms. Thereby, the droplet discharge amount can be adjusted, or the droplet landing position can be changed. Further, when different waveform shapes are used, at least one time and at least one of the maximum potential (crest value) of the drawing portion, the holding portion, and the pushing portion forming one waveform are set to be different from the other waveforms. be able to.

  FIG. 11 is a diagram illustrating a fourth modification of the drive signal. In the drive signal COM shown in FIG. 11, the shapes of the six waveforms w21 to w26 forming the waveform group are different from each other. In the example shown in FIG. 11, each of the waveforms w <b> 21 to w <b> 26 is set such that the maximum potential (crest value) gradually decreases as the waveform group comes later. When the drive signal COM shown in FIG. 11 is applied to the piezoelectric element 150, the ejection speed of the liquid droplets ejected from the nozzle opening 111 decreases every time the waveforms w21 to w26 are applied to the piezoelectric element 150. In addition, since the discharge amount decreases and the droplets become finer as the speed decreases, the impact at the time of landing of the droplets can be weakened.

  Considering the case where a certain amount of droplets are landed and filled in a predetermined landing area at a constant speed, when the first droplet is filled, the landing area is empty, so there is a risk that the droplets will overflow from the landing area However, there is a possibility that the landing area overflows as the number of ejected droplets increases. The discharge speed of the liquid droplets discharged using the drive signal COM shown in FIG. 11 is gradually reduced and the discharge amount is gradually reduced to prevent the liquid droplets discharged later from overflowing the landing area. Can do.

  Further, by selecting the waveform forming the waveform group using the selection signal SEL shown in FIGS. 9 and 10 with respect to the drive signal COM shown in FIG. 11, it is possible to finely adjust the droplet discharge amount. Become. Although FIG. 11 illustrates a case where all the shapes of the waveforms w21 to w26 forming the waveform group are different from each other, it is not always necessary to make the shapes of all the waveforms different. For example, the shape of the first three waveforms forming the waveform group may be the same, and the shape of the latter three waveforms may be different.

[Device manufacturing method]
Next, a device manufacturing method according to an embodiment of the present invention will be described. In the following description, a manufacturing method for manufacturing a color filter substrate using the above-described droplet discharge device IJ will be described as an example. FIG. 12 is a diagram showing a series of manufacturing steps of a color filter substrate including a step of forming an RGB pattern using the droplet discharge device IJ. Although the description is simplified in FIG. 1, it is assumed that the droplet discharge device IJ is configured to discharge R (red), G (green), and B (blue) droplets. .

  The substrate P used for manufacturing the color filter substrate is, for example, a rectangular thin plate-shaped transparent substrate, and has a high mechanical property and a high light transmission property. As this board | substrate P, a transparent glass substrate, acrylic glass, a plastic substrate, a plastic film, these surface treatment goods, etc. are used preferably, for example. Note that a plurality of color filter areas are formed in advance in a matrix on the substrate P from the viewpoint of increasing productivity in the pre-process of the RGB pattern forming process, and these color filter areas are formed after the RGB pattern forming process. By being cut in the process, it is used as a color filter substrate suitable for a liquid crystal display device.

  Here, FIG. 13 is a diagram showing an RGB pattern example formed by each droplet discharge device provided in the droplet discharge device IJ, (a) is a perspective view showing a stripe pattern, and (b). Is a partially enlarged view showing a mosaic type pattern, and (c) is a partially enlarged view showing a delta type pattern. As shown in FIG. 13, in each color filter region, an R (red) viscous body, a G (green) viscous body, and a B (blue) viscous body have a predetermined pattern from a droplet discharge head 18 described later. It is to be formed with. As this formation pattern, in addition to the stripe pattern shown in FIG. 13A, there are a mosaic pattern shown in FIG. 13B or a delta pattern shown in FIG. 13C. In the present invention, the formation pattern is not particularly limited. FIG. 13A shows an example in which droplets are ejected from the ejection head 20 to one B (blue) region for the sake of simplicity, but in order to improve production efficiency, the ejection head 20 is illustrated. Droplets are ejected to a plurality of regions at once.

  Returning to FIG. 12, in the black matrix forming step, which is the previous step, as shown in FIG. A non-resin (preferably black) is applied to a predetermined thickness (for example, about 2 μm) by a method such as spin coating, and then a black matrix BM,... Is formed in a matrix by a method such as photolithography. To go. The smallest display element surrounded by the lattice of these black matrixes BM is called a so-called filter element FE, and has a width dimension of 30 μm in one direction (for example, the X-axis direction) in the substrate P plane. The window has a length dimension of about 100 μm in a direction perpendicular to the direction (for example, the Y-axis direction). After forming the black matrix BM,... On the substrate P, the resin on the substrate P is baked by applying heat with a heater (not shown).

  The substrate P on which the black matrix BM is formed in this way is sucked and held on the stage ST, and an RGB pattern forming process using the droplet discharge device IJ shown in FIG. 1 is performed. In the RGB pattern forming step, first, as shown in FIG. 12B, red droplets RD are landed in filter elements FE,... At predetermined positions for forming a predetermined pattern. The amount of each droplet RD at this time is a sufficient amount considering the volume reduction amount of the droplet RD in the heating process.

  In this way, the substrate P after all the predetermined filter elements FE,... Are filled with the red droplets RD is dried at a predetermined temperature (for example, about 70 degrees). At this time, when the solvent of the droplet RD evaporates, the volume of the droplet RD decreases as shown in FIG. 12C. Therefore, when the volume is drastically reduced, a sufficient viscous film thickness as a color filter substrate is obtained. The landing operation and the drying operation of the droplet RD are repeated until the droplet RD is discharged. By this treatment, the solvent of the droplet RD evaporates, and finally only the solid content of the droplet RD remains to form a film.

  The dried substrate P is cooled and then held on the stage ST of the droplet discharge device IJ again. Then, as shown in FIG. 12B, green droplets GD are landed in the filter elements FE,... At predetermined positions for forming a predetermined pattern. The amount of each droplet GD at this time is a sufficient amount considering the volume reduction amount of the droplet GD in the heating process. In this way, the substrate P after the green droplets GD are filled in all the predetermined filter elements FE,... Is dried at a predetermined temperature (for example, about 70 degrees). At this time, when the solvent of the droplet GD evaporates, the volume of the droplet GD decreases as shown in FIG. 12C. Therefore, when the volume is drastically reduced, a sufficient thickness of the viscous material film as the color filter substrate is obtained. The landing operation and the drying operation of the droplet GD are repeated until the droplet GD is discharged. By this process, the solvent of the droplet GD evaporates, and finally only the solid content of the droplet GD remains to form a film.

  The dried substrate P is cooled and then held on the stage ST of the droplet discharge device IJ again. Then, as shown in FIG. 12B, blue droplets BD are landed in the filter elements FE,... At predetermined positions for forming a predetermined pattern. The amount of each droplet BD at this time is a sufficient amount considering the volume reduction amount of the droplet BD in the heating process. In this way, the substrate P after all the predetermined filter elements FE,... Are filled with the blue droplets BD is dried at a predetermined temperature (for example, about 70 degrees) as shown in FIG. Is done. At this time, when the solvent of the droplet BD evaporates, the volume of the droplet BD decreases. When the volume is drastically reduced, the landing operation of the droplet BD is performed until a sufficient viscous film thickness is obtained as a color filter. And the drying operation are repeated. By this treatment, the solvent of the droplet BD evaporates, and finally only the solid content of the droplet BD remains to form a film.

  Thus, the RGB pattern forming process is completed. Thereafter, the post-process shown in FIG. In the protective film forming step shown in FIG. 12D, which is one of the subsequent steps, heating is performed at a predetermined temperature for a predetermined time in order to completely dry the droplets RD, GD, and BD. When the drying is completed, the protective film CR is formed for the purpose of surface protection and surface planarization of the substrate P on which the viscous film is formed. The protective film CR is formed using a method such as a spin coating method, a roll coating method, or a ripping method. In the transparent electrode forming step shown in FIG. 12E following the protective film forming step, the transparent electrode TL is formed so as to cover the entire surface of the protective film CR by using a method such as sputtering or vacuum adsorption. In the patterning step shown in FIG. 12F following the transparent electrode formation step, the transparent electrode TL is patterned as the pixel electrode PL. Note that this patterning step is not necessary when a switching element such as a TFT (Thin Film Transistor) is used to drive the liquid crystal display panel. Through the steps described above, the color filter substrate CF shown in FIG.

  When discharging the red droplet RD, the green droplet GD, and the blue droplet BD using the droplet discharge device IJ described above and landing on the filter element FE, the first moving device 12 shown in FIG. The second moving device 14 is driven to move the ejection head 20 and the substrate P relatively. In order to ensure the landing accuracy of each droplet, the relative movement speed between the ejection head 20 and the substrate P is kept constant during the ejection of the droplet. For this reason, when the ejection frequency of the droplets from the ejection head 20 is low, the number of droplets that land on one filter element FE at a time decreases.

  FIG. 14 is a diagram illustrating an example of a landing state of droplets when the color filter substrate is manufactured. 14 indicates the relative movement direction of the ejection head 20 and the substrate P. When droplets are landed on the filter element FE set on the color filter substrate, the droplets are filtered when the droplets discharged from the opening nozzle 111 land on the black matrix BM (bank) surrounding the filter element FE. Since there is a possibility of overflowing from the element FE, the droplet is landed at a position separated by a predetermined distance Ga from both ends in the relative movement direction in consideration of the discharge error of the droplet.

  When the droplet discharge frequency is low, as shown in FIG. 14A, only about three droplets can be landed on one filter element FE at a time. For this reason, in order to fill the filter element FE with a sufficient amount of droplets, the number of the opening nozzles 111 of the ejection head 20 is increased, the relative movement speed between the ejection head 20 and the substrate P is decreased, and the surface of the substrate P It is necessary to take measures such as scanning the entire image several times. However, if the number of the opening nozzles 111 of the ejection head 20 is increased, the cost of the droplet ejection apparatus IJ increases and maintenance becomes difficult. Further, when the relative movement speed between the ejection head 20 and the substrate P is decreased or the number of scans on the entire surface of the substrate P is increased, the productivity is remarkably lowered, and the color due to uneven drying of the droplets RD, GD, and BD. There is a risk of unevenness.

  On the other hand, since the droplet discharge frequency can be increased by driving the piezoelectric element 150 using the driving method of the droplet discharge head of the present invention, for example, as shown in FIG. It is possible to land about 9 drops on the FE at a time. Thereby, since it is not necessary to reduce the relative movement speed of the ejection head 20 and the substrate P, productivity can be significantly improved. Further, since it is not necessary to scan over the entire surface of the substrate P, it is possible to prevent uneven drying of the droplets RD, GD, and BD, and to further improve the wetting and spreading of the droplets in the filter element FE. In addition, the uniformity of the film thickness can be improved. In addition, by discharging droplets using the drive waveform COM described with reference to FIG. 11, it is possible to effectively prevent the landed droplets from overflowing from the filter element FE.

  The liquid crystal display device is manufactured through a process in which the color filter substrate CF manufactured through the above manufacturing process and a counter substrate (not shown) are arranged to face each other and a liquid crystal is sandwiched therebetween. A laptop personal computer (device), for example, is manufactured by incorporating electronic components such as a liquid crystal display device, a motherboard including a CPU (central processing unit), a keyboard, and a hard disk manufactured in this manner into the housing. The

  In the above device manufacturing method, the landing operation and drying operation of the droplet RD are repeated, the landing operation and drying operation of the droplet GD are repeated, and the landing operation and drying operation of the droplet BD are repeated. As described above, the drying operation may not be performed until all the droplets have landed. Thereby, the uniformity of the film thickness can be further improved. In the above example, in order to completely dry the droplets RD, GD, and BD, heating is performed for a predetermined time at a predetermined temperature. However, baking may be performed after drying under reduced pressure. Thereby, the uniformity of the film thickness can be further improved.

  In the above example, the droplets RD, GD, and DB are landed separately, but the droplets RD, GD, and DB are landed simultaneously while the ejection head 20 and the substrate P are relatively moving. You may do it. Thereby, the time required for the landing of the droplet can be shortened. In the case of manufacturing the above device, a waveform group consisting of 28 waveforms is used. As a result, the number of droplets discharged per unit time can be dramatically increased.

[Other device manufacturing methods]
Further, the droplet discharge device IJ of this embodiment includes a film forming device or a microlens array for forming a film, a liquid crystal display device, an organic EL device, a plasma display device, a field emission display (FED), and the like. It can also be used for manufacturing. FIG. 15 and FIG. 16 are explanatory diagrams of a microlens array for an optical interconnection device manufactured using a droplet discharge device according to an embodiment of the present invention. In the discharge device, after a photosensitive transparent resin (liquid viscous material) is discharged from a droplet discharge head to a predetermined position of the object W1 made of the transparent substrate shown in FIGS. If microlenses L having a predetermined size are formed at predetermined positions above, microlens arrays 70a and 70b for an optical interconnection device can be manufactured.

  Here, in the microlens array 70a shown in FIG. 15, the microlenses L are arranged in a matrix in the X direction and the Y direction. Further, in the microlens array 70b shown in FIG. 16, the microlenses L are formed to be irregularly dispersed in the X direction and the Y direction. The macro lens array is used for a liquid crystal panel in addition to the optical interconnection device. However, in manufacturing the micro lens for the liquid crystal display device, if the ink jet type device to which the present invention is applied is used, Since it is not necessary to use a photolithography technique, the production efficiency of the microlens array can be improved.

  FIG. 17 is a cross-sectional view showing an example of the configuration of the organic EL device. As shown in FIG. 17, the organic EL device 301 includes an organic substrate composed of a substrate 311, a circuit element portion 321, a pixel electrode 331, a bank portion 341, a light emitting element 351, a cathode 361 (counter substrate), and a sealing substrate 371. A wiring of a flexible substrate (not shown) and a driving IC (not shown) are connected to the EL element 302. The circuit element portion 321 is formed on the substrate 311, and a plurality of pixel electrodes 331 are aligned on the circuit element portion 321. Bank portions 341 are formed in a lattice shape between the pixel electrodes 331, and light emitting elements 351 are formed in the recess openings 344 generated by the bank portions 341. The cathode 361 is formed on the entire upper surface of the bank portion 341 and the light emitting element 351, and a sealing substrate 371 is laminated on the cathode 361.

  The manufacturing process of the organic EL device 301 including the organic EL element includes a bank part forming step for forming the bank part 341, a plasma processing step for appropriately forming the light emitting element 351, and a light emitting element formation for forming the light emitting element 351. A process, a counter electrode forming process for forming the cathode 361, and a sealing process for stacking and sealing the sealing substrate 371 on the cathode 361.

  In the light emitting element forming step, the light emitting element 351 is formed by forming the hole injection / transport layer 352 and the light emitting layer 353 on the concave opening 344, that is, the pixel electrode 331. A light emitting layer forming step. The hole injection / transport layer forming step includes a first droplet discharge step of discharging a first composition (functional liquid) for forming the hole injection / transport layer 352 onto each pixel electrode 331, a discharge A first drying step of forming the hole injection / transport layer 352 by drying the first composition, and the light emitting layer forming step includes a second composition (functional liquid for forming the light emitting layer 353). ) On the hole injection / transport layer 352 and a second drying step of forming the light emitting layer 353 by drying the discharged second composition. In the light emitting element formation step, the light emitting element is formed using an ejection device.

  FIG. 18 is an exploded perspective view showing a part of the configuration of the plasma display device. As shown in FIG. 18, the plasma display device 400 includes substrates 401 and 402 disposed opposite to each other and a discharge display unit 410 formed between the substrates 401 and 402. The discharge display unit 410 is a collection of a plurality of discharge chambers 416. Among the plurality of discharge chambers 416, the three discharge chambers 416 of the red discharge chamber 416 (R), the green discharge chamber 416 (G), and the blue discharge chamber 416 (B) are arranged to form one pixel. Has been.

  Address electrodes 411 are formed in stripes at predetermined intervals on the upper surface of the substrate 401, and a dielectric layer 419 is formed so as to cover the address electrodes 411 and the upper surface of the substrate 401. A partition wall 415 is formed on the dielectric layer 419 so as to be positioned between the address electrodes 411 and 411 and along the address electrodes 411. The barrier ribs 415 include barrier ribs adjacent to both the left and right sides of the address electrode 411 in the width direction, and barrier ribs extending in a direction orthogonal to the address electrodes 411. A discharge chamber 416 is formed corresponding to a rectangular region partitioned by the partition 415. In addition, a phosphor 417 is disposed inside a rectangular region defined by the partition 415. The phosphor 417 emits red, green, or blue fluorescence. The red phosphor 417 (R) is located at the bottom of the red discharge chamber 416 (R) and the green discharge chamber 416 (G). A green phosphor 417 (G) is disposed at the bottom, and a blue phosphor 417 (B) is disposed at the bottom of the blue discharge chamber 416 (B).

  On the other hand, on the substrate 402, a plurality of display electrodes 412 are formed in stripes at predetermined intervals in a direction orthogonal to the previous address electrodes 411. Further, a dielectric layer 413 and a protective film 414 made of MgO or the like are formed so as to cover them. The substrate 401 and the substrate 402 are bonded to each other with the address electrode 411 and the display electrode 412 facing each other so as to be orthogonal to each other. The address electrode 411 and the display electrode 412 are connected to an AC power supply (not shown). When each electrode is energized, the phosphor 417 is excited and emits light in the discharge display unit 410 to enable color display. The ejection device according to the embodiment of the present invention is used to arrange the phosphor 417 inside a rectangular region partitioned by the partition 415.

  FIG. 19 is a diagram showing a configuration of a field emission display (FED) including a field emission device, and FIG. 19A is an exploded perspective view schematically showing a positional relationship between a cathode substrate and an anode substrate constituting the FED. FIG. 4B is a circuit diagram showing a schematic configuration of a drive circuit provided on the cathode substrate of the FED, and FIG. As shown in FIG. 19A, the FED 500 has a configuration in which a cathode substrate 500a and an anode substrate 500b are arranged to face each other.

As shown in FIGS. 19A and 19B, the cathode substrate 500 a is a so-called simple matrix drive including a gate line 501, an emitter line 502, and a field emission element 503 connected to the gate line 501 and the emitter line 502. It has a circuit. Gate signal _V 1 was in the gate line _{501, V 2, ..., V} m is supplied to the emitter line 502, the emitter signal _{W 1, W 2, ...,} W n is supplied. The anode substrate 500b includes a phosphor that emits light when hit by electrons, and a phosphor that emits red, green, or blue fluorescence is provided as the phosphor.

  As shown in FIG. 19C, the field emission device 503 includes an emitter electrode 503a connected to the emitter line 502 and a gate electrode 503b connected to the gate line 501. The emitter electrode 503a includes a protrusion called an emitter tip 505 that decreases in diameter from the emitter electrode 503a toward the gate electrode 503b. A hole 504 is formed in the gate electrode 503b at a position corresponding to the emitter tip 505. The tip of the emitter tip 505 is disposed in the hole 504.

When a voltage is supplied between the emitter electrode 503 a and the gate electrode 503 b provided in the field emission element 503, the electrons 510 move from the emitter tip 505 toward the hole 504 due to the action of the electric field, and from the tip of the emitter tip 505. Electrons 510 are emitted. The emitted electrons 510 strike the phosphor of the anode substrate 500b disposed to face the cathode substrate 500a, so that the phosphor emits light. Therefore, the gate signal _{V 1,} V 2 of the gate lines 501, ..., _{V m,} and the emitter signals _{W 1,} W 2 of the emitter line 502, ..., a desired color by driving the FED500 by controlling the _{W n} It can be displayed. The discharge device according to the embodiment of the present invention is used for arranging a phosphor on the anode substrate 500b.

  Devices such as the above-described liquid crystal display device, organic EL device, plasma display device, and FED are provided in electronic devices such as notebook computers and mobile phones. However, the electronic device according to the present invention is not limited to the above-described notebook computer and mobile phone, and can be applied to various electronic devices. For example, LCD projectors, multimedia-compatible personal computers (PCs) and engineering workstations (EWS), pagers, word processors, TVs, viewfinder type or monitor direct view type video tape recorders, electronic notebooks, electronic desk calculators, car navigation systems The present invention can be applied to electronic devices such as a device, a POS terminal, and a device provided with a touch panel.

1 is a perspective view showing a schematic configuration of a droplet discharge device according to an embodiment of the present invention. 3 is an exploded perspective view of the ejection head 20. FIG. 3 is a perspective view showing a part of the main part of the ejection head 20. FIG. It is a block diagram which shows the electrical function structure of the droplet discharge apparatus by one Embodiment of this invention. It is a figure which shows an example of the basic waveform of the drive signal COM. FIG. 6 is a diagram illustrating an operation when a piezoelectric element 150 is ejecting droplets. It is a figure which shows the discharge condition of the droplet discharged from the nozzle opening 111 using the drive signal of this embodiment. It is a figure which shows the 1st modification of a drive signal. It is a figure which shows the 2nd modification of a drive signal. It is a figure which shows the 3rd modification of a drive signal. It is a figure which shows the 4th modification of a drive signal. It is a figure which shows a series of manufacturing processes of the color filter board | substrate including the process of forming RGB pattern using the droplet discharge apparatus IJ. It is a figure which shows the RGB pattern example formed by each droplet discharge apparatus with which the droplet discharge apparatus IJ is provided. It is a figure which shows an example of the landing condition of the droplet at the time of color filter board | substrate manufacture. It is explanatory drawing of a micro lens array. It is explanatory drawing of a micro lens array. It is sectional drawing which shows an example of a structure of an organic electroluminescent apparatus. It is a disassembled perspective view which shows a part of structure of a plasma type display apparatus. It is a figure which shows the structure of the field emission display (FED) provided with the field emission element.

Explanation of symbols

20 …… Discharge head (droplet discharge head)
26 …… Control device (drive unit)
60 …… Drive circuit (drive unit)
111 …… Nozzle opening 121 …… Cavity 150 …… Piezoelectric element (pressure generating element)
c1, c2, ..... pull-in part (first waveform part)
d1, d2, ......... extruded part (third corrugated part)
h1, h2, ..... holding part (second waveform part)
i1, i2, ..... pull-in part (fourth waveform part)
COM …… Drive signal w0 …… Suppression waveform w11, w12 …… Termination waveform

Claims (18)

A cavity for storing a predetermined liquid; a pressure generating element for generating a pressure in the cavity according to an applied drive signal; and a nozzle opening for discharging the liquid pressurized by the pressure generating element as a droplet A method of driving a droplet discharge head comprising:
A method for driving a droplet discharge head, wherein the drive signal is applied to the pressure generating element in substantially synchronism with a vibration cycle of the liquid contained in the cavity at the nozzle opening. The drive signal includes a waveform group composed of at least two continuous waveforms;
2. The method of driving a droplet discharge head according to claim 1, wherein the waveform group is applied to the pressure generating element substantially in synchronization with a vibration cycle of the liquid.   The reference level of the waveform includes the droplet discharged from the nozzle opening when the first waveform included in the waveform group is applied to the pressure generating element, and the second level included in the waveform group. The droplet discharge head according to claim 2, wherein a distance from the droplet discharged from the nozzle opening is substantially minimized when a waveform is applied to the pressure generating element. Driving method.   The waveform includes a first waveform part that increases the volume of the cavity to generate a negative pressure in the cavity, a second waveform part that stops driving the pressure generating element for a certain period of time, and the volume of the cavity decreases rapidly. 4. The droplet discharge head according to claim 2, further comprising a third waveform portion that pressurizes the cavity and a fourth waveform portion that stops driving the pressure generating element for a predetermined time. Driving method.   5. The method of driving a droplet discharge head according to claim 4, wherein the drive signal includes a suppression waveform that suppresses vibration of the liquid in the nozzle opening.   6. The droplet discharge head according to claim 4, wherein the time of the first waveform portion and the third waveform portion is set to a time substantially equal to a natural vibration period of the pressure generating element. Driving method.   The time of the second waveform portion and the fourth waveform portion is such that when the waveform group is applied to the pressure generating element, the weight variation of each droplet discharged from the nozzle opening is minimized. The method of driving a droplet discharge head according to any one of claims 4 to 6, wherein the driving method is set.   After the waveform group is applied to the pressure generating element, a termination waveform for generating a negative pressure in the cavity by increasing the volume of the cavity over a time substantially equal to the natural vibration period of the pressure generating element 8. The method for driving a droplet discharge head according to claim 4, wherein the method is applied to a pressure generating element.   After applying the group of waveforms to the pressure generating element, a terminal waveform for generating a negative pressure in the cavity by increasing the volume of the cavity for at least approximately the same period as the vibration period of the liquid in the nozzle opening. The method of driving a droplet discharge head according to any one of claims 4 to 7, wherein a pressure is applied to the pressure generating element.   10. The method of driving a droplet discharge head according to claim 4, wherein at least one waveform included in the waveform group is different in shape from other waveforms.   The at least one waveform included in the waveform group is different from the other waveforms in at least one of time and peak value of at least one of the first to fourth waveform portions. 10. A method for driving a droplet discharge head according to 10.   12. The droplet ejection head driving method according to claim 10, wherein the waveforms having different shapes are a first waveform or a last waveform included in the waveform group.   13. The droplet discharge head drive according to claim 10, wherein a waveform having a different shape and a waveform having the same shape as the other waveform can be alternatively selected. Method.   10. The method of driving a droplet discharge head according to claim 4, wherein each of the waveforms included in the waveform group has a different shape from each other. 11.   15. The method of driving a droplet discharge head according to claim 14, wherein each of the waveforms included in the waveform group is a waveform in which a peak value gradually decreases. A cavity for storing a predetermined liquid; a pressure generating element for generating a pressure in the cavity according to an applied drive signal; and a nozzle opening for discharging the liquid pressurized by the pressure generating element as a droplet A droplet discharge device comprising a droplet discharge head having
A liquid droplet ejection apparatus comprising: a drive unit that applies the drive signal to the pressure generating element substantially in synchronization with a vibration cycle of the liquid contained in the cavity at the nozzle opening. A method for manufacturing a device including a workpiece having a pattern having functionality at a predetermined location,
The method for driving the droplet discharge device according to any one of claims 1 to 15, or the predetermined opening from the nozzle opening provided in the droplet discharge head using the droplet discharge device according to claim 16. A device manufacturing method comprising a discharging step of discharging a liquid. A device manufactured using the device manufacturing method according to claim 17.

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