Inkjet printing method

Abstract

The inkjet printing method includes the steps of: confirming an ink discharge amount of each of a plurality of nozzles provided along a plurality of nozzle rows; setting a variable range of the ink discharge amount corresponding to each of the plurality of nozzle rows; the control unit sets a plurality of combinations of a plurality of drive waveforms for performing control so that ink ejection amounts different from each other are ejected. And discharging ink to the plurality of pixel regions while changing a combination of the plurality of drive waveforms for each of the plurality of pixel regions.

Description

Technical Field

[0001] The present invention relates to an inkjet printing method and more particularly to an inkjet printing method and an inkjet printer for performing the inkjet printing method. Background Art

[0002] The display device includes a display panel having a plurality of films formed on a substrate. For example, the substrate may be a rigid substrate including glass or a flexible substrate including polyimide. Some of the films provided on the substrate may be formed by an inkjet process.

[0003] The inkjet process may be performed by forming a partition wall or the like on a substrate and using an inkjet printer that spits ink into an opening defined by the partition wall or the like. The size of the inkjet head may be relatively small compared to the substrate. Therefore, the steps of moving the substrate or the inkjet head included in the inkjet printer and spits ink may be repeatedly performed. Summary of the invention

[0004] An object of the present invention is to provide an inkjet printing method having improved reliability.

[0005] Another object of the present invention is to provide a display device manufactured by an inkjet printing method.

[0006] However, the purpose of the present invention is not limited to this purpose, and can be expanded in various ways without departing from the spirit and scope of the present invention.

[0007] In order to achieve the purpose of the present invention, an inkjet printing method of an embodiment of the present invention may include the following steps: confirming the ink discharge volume of each of the multiple nozzles arranged along multiple nozzle columns; setting a variable range of the ink discharge volume corresponding to the multiple nozzle columns; setting multiple combinations of multiple driving waveforms for controlling the discharge of different ink discharge volumes; and discharging ink to multiple pixel areas while changing the combination of multiple driving waveforms for each pixel area in the multiple pixel areas.

[0008] In one embodiment, the variable range of the ink ejection amount may be set within a range of approximately -3% to approximately +3% of the ink ejection amount of each of the plurality of nozzles.

[0009] In one embodiment, the inkjet printing method may further include the following step before the step of setting a plurality of combinations of a plurality of driving waveforms: inputting a target volume of each of a plurality of pixel regions.

[0010] In one embodiment, the inkjet printing method may further include the step of selecting a nozzle group including a part of the plurality of nozzles corresponding to the plurality of combinations of the plurality of driving waveforms after the step of setting the plurality of combinations of the plurality of driving waveforms.

[0011] In one embodiment, the step of setting multiple combinations of multiple driving waveforms may include: setting a combination of a first timing driving waveform for controlling to discharge a first ink discharge amount; setting a combination of a second timing driving waveform for controlling to discharge a second ink discharge amount that is smaller than the first ink discharge amount; and setting a combination of a third timing driving waveform for controlling to discharge a third ink discharge amount that is larger than the first ink discharge amount.

[0012] In one embodiment, in the step of setting a plurality of combinations of a plurality of driving waveforms, the combination of the first timing driving waveform and the combination of the second timing driving waveform may be set to have different driving waveforms for each of the plurality of nozzles included in each of the plurality of nozzle columns.

[0013] In one embodiment, in the step of ejecting ink while changing a combination of a plurality of driving waveforms for each of a plurality of pixel areas, a set number of combinations of the second timing driving waveforms and a set number of combinations of the third timing driving waveforms may be the same.

[0014] In one embodiment, the step of spitting ink to multiple pixel areas while changing a combination of multiple driving waveforms for each of the multiple pixel areas may include: in a first pixel area among the multiple pixel areas, applying a combination of second timing driving waveforms to multiple nozzles; and in a second pixel area among the multiple pixel areas adjacent to the first pixel area in a moving direction of the multiple nozzles, applying a combination of third timing driving waveforms to the multiple nozzles.

[0015] In one embodiment, the step of spitting ink to multiple pixel areas while changing a combination of multiple driving waveforms for each of the multiple pixel areas may include: in a first pixel area among the multiple pixel areas, applying a combination of first timing driving waveforms to multiple nozzles; and in a second pixel area among the multiple pixel areas that is adjacent to the first pixel area in a moving direction of the multiple nozzles, applying a combination of second timing driving waveforms to the multiple nozzles.

[0016] In one embodiment, the step of spitting ink to multiple pixel areas while changing the combination of multiple driving waveforms for each pixel area may include: in a first pixel area among the multiple pixel areas, applying a combination of first timing driving waveforms to multiple nozzles; and in a second pixel area among the multiple pixel areas adjacent to the first pixel area in a moving direction of the multiple nozzles, applying a combination of third timing driving waveforms to the multiple nozzles.

[0017] In order to achieve the purpose of the present invention, an inkjet printer according to an embodiment of the present invention may include: a plurality of nozzles arranged along a plurality of nozzle columns; and a controller. The controller may include: an input unit to which the ink ejection amount of each of the plurality of nozzles is input; a condition setting unit to set a variable range of the ink ejection amount corresponding to each of the plurality of nozzle columns; a waveform setting unit to set a plurality of combinations of a plurality of driving waveforms for controlling to eject different ink ejection amounts; and an output unit to output an ejection control signal for ejecting ink to the plurality of pixel areas to the nozzle while changing the combination of the plurality of driving waveforms for each of the plurality of pixel areas.

[0018] In one embodiment, the variable range of the ink discharge amount may be within a range of approximately -3% to approximately +3% of the ink discharge amount of each of the plurality of nozzles.

[0019] In one embodiment, the input unit may further input target volumes of the plurality of pixel regions.

[0020] In one embodiment, the controller may further include a nozzle setting unit for selecting a nozzle group including a portion of the plurality of nozzles corresponding to the plurality of combinations of the plurality of driving waveforms, respectively.

[0021] In one embodiment, the waveform setting unit can set a combination of a first timing drive waveform for controlling the discharge of a first ink discharge amount, a combination of a second timing drive waveform for controlling the discharge of a second ink discharge amount that is smaller than the first ink discharge amount, and a combination of a third timing drive waveform for controlling the discharge of a third ink discharge amount that is larger than the first ink discharge amount.

[0022] In one embodiment, the output unit may change the combination of the plurality of driving waveforms for each of the plurality of pixel regions so that the number of the combination of the second timing driving waveforms is equal to the number of the combination of the third timing driving waveforms.

[0023] In one embodiment, the waveform setting unit may set the combination of the first timing driving waveforms and the combination of the second timing driving waveforms to have different driving waveforms for each of the plurality of nozzle columns.

[0024] In one embodiment, the output unit may output a second control signal so that a combination of second timing drive waveforms is applied to multiple nozzles in a first pixel area among multiple pixel areas, and output a third control signal so that a combination of third timing drive waveforms is applied to multiple nozzles in a second pixel area among multiple pixel areas that is adjacent to the first pixel area in the direction in which the multiple nozzles move.

[0025] In one embodiment, the output unit may output a first control signal so that a combination of first timing drive waveforms is applied to multiple nozzles in a first pixel area among multiple pixel areas, and output a second control signal so that a combination of second timing drive waveforms is applied to multiple nozzles in a second pixel area among multiple pixel areas that is adjacent to the first pixel area in a direction in which the multiple nozzles move.

[0026] In one embodiment, the output unit may output a first control signal so that a combination of first timing drive waveforms is applied to multiple nozzles in a first pixel area among multiple pixel areas; and output a third control signal so that a combination of third timing drive waveforms is applied to multiple nozzles in a second pixel area among multiple pixel areas that is adjacent to the first pixel area in the direction in which the multiple nozzles move.

[0027] An inkjet printing method according to an embodiment of the present invention may include the following steps: confirming the ink ejection amount of each of the plurality of nozzles arranged along the plurality of nozzle columns; setting a variable range of the ink ejection amount corresponding to each of the plurality of nozzle columns; setting a plurality of combinations of a plurality of driving waveforms for controlling to eject different ink ejection amounts; and ejecting ink to the plurality of pixel areas while changing the combination of the plurality of driving waveforms for each of the plurality of pixel areas. Thus, a display device that prevents the generation of streaks and spots can be manufactured.

[0028] An inkjet printer according to an embodiment of the present invention may include: a plurality of nozzles arranged along a plurality of nozzle columns; and a controller. The controller may include: an input unit to which the ink ejection amount of each of the plurality of nozzles is input; a condition setting unit to set a variable range of the ink ejection amount corresponding to each of the plurality of nozzle columns; a waveform setting unit to set a plurality of combinations of a plurality of driving waveforms for controlling the ejection of different ink ejection amounts; and an output unit to output an ejection control signal for ejecting ink to the plurality of pixel areas to the nozzle while changing the combination of the plurality of driving waveforms for each of the plurality of pixel areas. Thus, a display device that prevents the generation of streaks and spots can be manufactured.

[0029] However, the effects of the present invention are not limited to the above effects, and can be expanded in various ways without departing from the spirit and scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a diagram for explaining an inkjet printer according to an embodiment of the present invention.

[0031] Figure 2 It is used to describe the Figure 1 A plan view of an inkjet head in an inkjet printer.

[0032] Figure 3 It is used to illustrate Figure 2 Diagram of the operation of the inkjet head.

[0033] Figure 4 It is used to describe the Figure 1 Block diagram of a controller in an inkjet printer.

[0034] Figures 5 to 15 It is a diagram for explaining an inkjet printing method according to an embodiment of the present invention.

[0035] Fig.16 It is used to illustrate the previous reference Figures 5 to 15 A diagram illustrating the effect of the inkjet printing method.

[0036] Description of Reference Numerals

[0037] PXA: Pixel Area HE: Inkjet Head

[0038] RR: Multiple nozzles row NO: Multiple nozzles

[0039] DW: Drive Waveform IK: Ink DETAILED DESCRIPTION

[0040] Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The same reference numerals are used for the same structural elements in the accompanying drawings, and repeated descriptions of the same structural elements are omitted.

[0041] Figure 1 It is a diagram for explaining an inkjet printer according to an embodiment of the present invention.

[0042] refer to Figure 1 An inkjet printer 1 according to an embodiment of the present invention may include an inkjet head HE, a driver DR, and a controller CON.

[0043] The inkjet printer 1 is a device that can form a film by ejecting ink IK onto a substrate SUB. The substrate SUB and the inkjet printer 1 can be installed on a stage.

[0044] The inkjet head HE may eject the ink IK onto the substrate SUB. To this end, in one embodiment, the inkjet head HE may be disposed on the substrate SUB. For example, the inkjet head HE may be disposed on the substrate SUB in a direction intersecting a plane defined by the first direction D1 and the second direction D2 (i.e., in a direction opposite to the direction of gravity). The inkjet printer 1 may include a plurality of inkjet heads HE according to the size of the substrate SUB.

[0045] The inkjet head HE may be connected to a driver DR. For example, the driver DR may be a linear driving device. In this case, the inkjet head HE may move in a first direction D1. Alternatively, the inkjet head HE may move in a second direction D2. For example, the driver DR may be a rotation driving device. In this case, the inkjet head HE may rotate about the first direction D1. Alternatively, the inkjet head HE may rotate about the second direction D2.

[0046] However, the present invention is not limited to this. For example, the driver DR may move the worktable. For example, the inkjet head HE may be fixed, and the driver DR may move the worktable. As another example of controlling to eject the ink IK, the driver DR may move the worktable and the inkjet head HE simultaneously.

[0047] In one embodiment, a plurality of pixel areas PXA may be defined in the substrate SUB. For example, the plurality of pixel areas PXA may be about several thousand. For example, the size of one side of each of the plurality of pixel areas PXA may be about tens of micrometers (μm) to about hundreds of micrometers (μm).

[0048] However, the present invention is not limited thereto, and the size of each of the plurality of pixel areas PXA may be varied in various ways depending on the type of display device and the like.

[0049] In one embodiment, according to the size of the substrate SUB, the inkjet head HE may be positioned to overlap only a portion of the pixel areas PXA (see FIG. Figure 5 ). For example, the size of one side of the inkjet head HE may be about several millimeters (mm). Therefore, the inkjet head HE may overlap with a plurality of pixel areas PXA of about tens to about hundreds.

[0050] However, the present invention is not limited thereto. The number of the plurality of pixel areas PXA overlapping the inkjet head HE may vary according to the size of the inkjet head HE, the size of each of the plurality of pixel areas PXA, and the like.

[0051] In one embodiment, the inkjet head HE may include a plurality of nozzles NO. Each of the plurality of nozzles NO may eject ink IK. The ejection amount of the ink IK ejected from each of the plurality of nozzles NO may be different from each other. Hereinafter, the ejection amount of the ink IK is used in the same meaning as the ejection amount. Optionally, the ejection amount of each of the plurality of nozzles NO may also be the same.

[0052] Each of the plurality of nozzles NO can be independently controlled by a controller CON described later. In other words, the ejection amount of each of the plurality of nozzles NO can be independently controlled by a controller CON described later.

[0053] For example, the controller CON may control the operation of the driver DR. The controller CON may output (or provide) a drive control signal to the driver DR. The drive control signal may cause the workbench to move. Optionally, the drive control signal may also cause the inkjet head HE to move. For example, the controller CON may control the operation of the inkjet head HE. The controller CON may provide an ejection control signal to the inkjet head HE. The ejection control signal may include information related to the ejection amount.

[0054] However, the present invention is not limited thereto. For example, the controller CON may control operations of various structures included in the inkjet printer 1.

[0055] Figure 1 For example, the inkjet printer 1 may further include structures required when performing the inkjet process (eg, a cleaning device, a sensor, etc.).

[0056] Figure 2 It is used to describe the Figure 1 A plan view of an inkjet head in an inkjet printer.

[0057] refer to Figure 2 In one embodiment, the inkjet head HE may include a plurality of nozzles NO arranged along a plurality of nozzle columns RR. For example, the plurality of nozzle columns RR may be arranged spaced apart from each other in the first direction D1. For example, the plurality of nozzle columns RR may include a first column R1 to an Nth column RN. N may be a natural number greater than 2.

[0058] In each of the plurality of nozzle rows RR, a plurality of nozzles NO may be spaced apart from one another in the second direction D2.

[0059] Although in Figure 2 Although the plurality of nozzle rows RR each include 16 nozzles, the present invention is not limited thereto. The number, size, arrangement interval, and arrangement position of the plurality of nozzles NO included in each of the plurality of nozzle rows RR may be modified in various ways.

[0060] Figure 3 It is used to illustrate Figure 2 Diagram of the operation of the inkjet head.

[0061] refer to Figure 2 and Figure 3 The inkjet head HE may include an energy generating portion ESP, a reservoir RES and a plurality of nozzles NO.

[0062] The energy generating unit ESP may be a device for providing energy for controlling the ejection of the ink IK. For example, the energy generating unit ESP may be a piezoelectric element (piezo).

[0063] However, the present invention is not limited thereto. For example, the energy generating unit ESP may be an electrothermal conversion element (eg, a heater), an electromechanical conversion element (eg, an electrostatic actuator), or the like.

[0064] The reservoir RES may provide a space for temporarily storing the ink IK.

[0065] The driving waveform DW may be an electrical signal. For example, when a predetermined driving waveform DW is output to the inkjet head HE, the energy generating unit ESP may be deformed (see Figure 3 (a)). In case the energy generating unit ESP is deformed, the volume of the storage RES can be increased (see Figure 3 (b)). The ink IK may flow into the reservoir RES with the volume change amount. Thereafter, the reservoir RES may be changed back to the original state, and the ink IK may be ejected from the plurality of nozzles NO with the volume change amount (see Figure 3 (c)).

[0066] For example, the volume change amount of the reservoir RES may vary according to the voltage. For example, the greater the voltage, the greater the amount of ink IK that the reservoir RES can temporarily store. However, the present invention is not limited thereto. For example, the volume change amount of the reservoir RES may also vary according to the pulse width.

[0067] Figure 4 It is used to describe the Figure 1 Block diagram of a controller in an inkjet printer.

[0068] refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 In one embodiment, the controller CON may include an input part IP, a condition setting part CS, a waveform setting part WS, a nozzle setting part NS and an output part OP.

[0069] Various data IDs associated with the inkjet process may be input to the input unit IP. In one embodiment, the input unit IP may be input with the ejection amount of the ink IK of each of the plurality of nozzles NO. For example, each of the plurality of nozzles NO may eject ink IK of approximately several picoliters (pL) to approximately tens of picoliters (pL). In one embodiment, the input unit IP may be input with the target volume to be ejected to each of the plurality of pixel areas PXA. For example, the target volume may be approximately 40 pL.

[0070] In one embodiment, the condition setting unit CS may set a variable range of the discharge amount corresponding to each of the plurality of nozzle rows RR. In one embodiment, the variable range of the discharge amount may be set within a range of about 3% of the discharge amount of each of the plurality of nozzles NO. In other words, the variable range of the discharge amount may be set within a range of about -3% to about +3%. For example, in the case where the discharge amount is about 10 pL, the variable range of the discharge amount may be set within a range of about 9.7 pL to about 10.3 pL.

[0071] In one embodiment, the waveform setting part WS may set a plurality of combinations of a plurality of driving waveforms corresponding to a plurality of pixel areas PXA, respectively.

[0072] In one embodiment, the nozzle setting part NS may calculate nozzle groups including a part of the plurality of nozzles NO respectively corresponding to the plurality of combinations of the plurality of driving waveforms, and may select the nozzle groups to be used in the inkjet process.

[0073] In one embodiment, the output unit OP may output a plurality of control signals OD associated with the inkjet process. In one embodiment, the output unit OP may output a discharge control signal for controlling the discharge of ink IK to the plurality of pixel areas PXA while changing a combination of a plurality of driving waveforms for each of the plurality of pixel areas PXA. In one embodiment, the discharge control signal may be provided to the inkjet head HE (e.g., each of the plurality of nozzle columns RR).

[0074] The detailed description of the functions of the components included in the controller CON will be referred to later. Figures 5 to 15 Give a narrative.

[0075] Figures 5 to 15 is a diagram for explaining an inkjet printing method according to an embodiment of the present invention. For example, the inkjet printing method may be Figure 1 The inkjet printer 1 performs the following. Figures 1 to 4 The description of the inkjet printer 1 described above is repeated.

[0076] refer to Figure 1 , Figure 2 , Figure 4 , Figure 5 and Figure 6 In one embodiment, the ejection volume of each of the plurality of nozzles NO arranged along the plurality of nozzle rows RR may be confirmed (step S100 ).

[0077] For example, a plurality of pixel areas PXA may be defined on the substrate SUB. For example, the inkjet head HE may be positioned to overlap the first pixel area PX1, the second pixel area PX2, the third pixel area PX3, the fourth pixel area PX4, the fifth pixel area PX5, the sixth pixel area PX6, the seventh pixel area PX7, and the eighth pixel area PX8.

[0078] For example, the inkjet head HE may include three nozzle columns overlapping the first pixel area PX1, the second pixel area PX2, the third pixel area PX3, the fourth pixel area PX4, the fifth pixel area PX5, the sixth pixel area PX6, the seventh pixel area PX7, and the eighth pixel area PX8. Each of the plurality of nozzle columns RR may include 16 nozzles. Each of the plurality of pixel areas PXA may overlap with six nozzles.

[0079] For example, as described above, the inkjet head HE may be moved along the printing direction PD, or the substrate SUB (for example, a stage on which the substrate SUB is placed) may be moved along the printing direction PD.

[0080] However, the present invention is not limited thereto. For example, the number of the plurality of pixel areas PXA overlapping the inkjet head HE may be varied in various ways. In addition, the number of the plurality of nozzle arrays RR included in the inkjet head HE, the number of the plurality of nozzles NO included in each of the plurality of nozzle arrays RR, the number of the plurality of nozzles NO respectively overlapping the plurality of pixel areas PXA, etc. may be varied in various ways.

[0081] In addition, although Figure 6 In the above description, the printing direction PD is parallel to the first direction D1, but the present invention is not limited thereto. For example, the printing direction PD may also be parallel to the second direction D2.

[0082] refer to Figure 1 , Figure 6 and Figure 7 In one embodiment, a variable range of the discharge amount corresponding to each of the plurality of nozzle rows RR may be set (step S200). In one embodiment, the variable range of the discharge amount may be set within a range of approximately 3% of the discharge amount. In other words, the variable range of the discharge amount may be set within a range of approximately -3% to approximately +3%.

[0083] The plurality of nozzles NO may have different ejection volumes. For example, the plurality of nozzles NO may eject ink IK in an amount of about several pL to about several tens of pL.

[0084] Each of the plurality of nozzles NO may have an error in discharge amount. The error in discharge amount may be caused by interference of the driving waveform and the storage (e.g., Figure 3 For example, the discharge amount error may occur within approximately several percentages.

[0085] For example, in a case where the variable range of the ejection amount exceeds about 3%, ink IK that deviates from the error tolerance range of the target volume may be ejected into each of the multiple pixel areas PXA. For example, in a case where the target volume is about 40pL, the error tolerance range may be within a range of about 2%. In other words, the error tolerance range may be about 39.2pL to about 40.8pL. In a case where the variable range of the ejection amount exceeds about 3%, ink IK exceeding about 41.2pL may be ejected into each of the multiple pixel areas PXA. In this case, linemura may be generated between an area where ink IK within the error tolerance range is ejected and an area where more ink IK than the error tolerance range is ejected. This may manifest as a decrease in display quality.

[0086] In addition, in the case where the variable range of the ejection amount exceeds about -3% (for example, in the case where the variable range of the ejection amount is about -4%), ink IK that deviates from the error tolerance range of the target volume may be ejected into a plurality of pixel areas PXA. For example, in the case where the target volume is about 40 pL, ink IK less than about 38.8 pL may be ejected into a plurality of pixel areas PXA. In this case, streaks and spots may be generated between an area where ink IK within the error tolerance range is ejected and an area where ink IK less than the error tolerance range is ejected. In this case, a decrease in display quality may also be exhibited.

[0087] In addition, when the variable range of the discharge amount deviates from the range of about 3% (for example, when the variable range of the discharge amount is about 4%), satellites may be generated. Satellites may refer to small-volume droplets that may be generated during the ink process.

[0088] Therefore, in order to prevent the generation of streaks and satellites, in one embodiment, the variable range of the ejection amount can be set within a range of about 3% of the ejection amount of the ink IK. In other words, the variable range of the ejection amount can be set within a range of about -3% to about +3%.

[0089] For example, in the case where approximately 10.22 pL of the ink IK can be ejected, each of the plurality of nozzles NO may be set to have an ejection amount between approximately 9.91 pL and approximately 10.52 pL.

[0090] refer to Figure 1 , Figure 2 , Figure 4 , Figure 6 , Figure 8 , Fig. 9 and Fig.10In one embodiment, a target volume may be input, and a plurality of combinations of a plurality of driving waveforms DWA, DWB, DWC may be set (step S400). The plurality of combinations of a plurality of driving waveforms DWA, DWB, DWC may each control the inkjet head HE (or may control a plurality of nozzles NO) so as to eject ink IK of different ejection amounts to each of a plurality of pixel areas PXA defined in a substrate SUB.

[0091] In one embodiment, the waveform setting part WS may set the combination DWA of the first timing drive waveform, the combination DWB of the second timing drive waveform, and / or the combination DWC of the third timing drive waveform. In one embodiment, the waveform setting part WS may set so that the combination DWA of the first timing drive waveform, the combination DWB of the second timing drive waveform, and / or the combination DWC of the third timing drive waveform each have a different drive waveform from each other for each of the plurality of nozzles NO included in the plurality of nozzle rows RR.

[0092] For example, Figure 8 As shown in FIG. 1 , in one embodiment, the combination DWA of the first timing driving waveform can control the inkjet head HE (or the plurality of nozzles NO) to discharge a first discharge amount. For example, the combination DWA of the first timing driving waveform can include a combination DW1 of the first driving waveform, a combination DW2 of the second driving waveform, a combination DW3 of the third driving waveform, a combination DW4 of the fourth driving waveform, and a combination DW5 of the fifth driving waveform.

[0093] In one embodiment, the combination DWA of the first timing driving waveforms may be set so that each of the plurality of nozzle rows RR has a driving waveform different from each other.

[0094] For example, in the case of the second drive waveform combination DW2, the first column R1 may include a control for controlling the discharge amount to be greater than the normal discharge amount (for example, in the previous reference Figure 5 and Figure 6 The second column R2 may include a driving waveform for controlling so that the normal discharge amount is discharged, and the third column R3 may include a driving waveform for controlling so that the discharge amount is increased by about 3% compared with the normal discharge amount.

[0095] In the case of the third drive waveform combination DW3, the first column R1 may include a drive waveform for controlling the discharge amount to be approximately 3% less than the normal discharge amount, the second column R2 may include a drive waveform for controlling the discharge amount to be approximately 3% more than the normal discharge amount, and the third column R3 may include a drive waveform for controlling the discharge amount to be approximately 3% more than the normal discharge amount.

[0096] In the case of the fourth drive waveform combination DW4, the first column R1 may include a drive waveform for controlling the discharge amount to increase by approximately 3% compared to the conventional discharge amount, the second column R2 may include a drive waveform for controlling the discharge amount to decrease by approximately 3% compared to the conventional discharge amount, and the third column R3 may include a drive waveform for controlling the discharge amount to be discharged.

[0097] In the case of the fifth drive waveform combination DW5, the first column R1 may include a drive waveform for controlling the discharge amount to increase by approximately 3% compared to the conventional discharge amount, the second column R2 may include a drive waveform for controlling the discharge amount to be discharged, and the third column R3 may include a drive waveform for controlling the discharge amount to be reduced by approximately 3% compared to the conventional discharge amount.

[0098] However, the present invention is not limited thereto. For example, in the case of the first drive waveform combination DW1, each of the first column R1, the second column R2, and the third column R3 may include a drive waveform for controlling to discharge the normal discharge amount.

[0099] For example, Fig. 9 As shown in FIG. 1 , in one embodiment, the combination DWB of the second timing driving waveform can be controlled so as to discharge a second discharge amount. The second discharge amount can be smaller than the first discharge amount (the total discharge amount when discharge is performed from a plurality of nozzles NO).

[0100] For example, the second timing driving waveform combination DWB may include a sixth driving waveform combination DW6, a seventh driving waveform combination DW7, an eighth driving waveform combination DW8, a ninth driving waveform combination DW9, a tenth driving waveform combination DW10, and an eleventh driving waveform combination DW11.

[0101] For example, the combination DWB of the second timing driving waveform may include two driving waveforms for controlling the discharge amount to be reduced by about 3% compared to the conventional discharge amount and one driving waveform for controlling the discharge amount to be increased by about 3% compared to the conventional discharge amount. Thus, the discharge amount (or total amount) generated by the combination DWB of the second timing driving waveform may be smaller than the discharge amount (or total amount) generated by the combination DWA of the first timing driving waveform.

[0102] For example, the sixth drive waveform combination DW6, the seventh drive waveform combination DW7, the eighth drive waveform combination DW8, the ninth drive waveform combination DW9, the tenth drive waveform combination DW10 and the eleventh drive waveform combination DW11 may each differ only in the order in which the drive waveforms are set.

[0103] However, the present invention is not limited to this. For example, the variable range of the discharge amount can be changed in various ways, and thereby the combination DWB of the second timing drive waveform can also be varied.

[0104] For example, Fig.10 As shown in FIG. 1 , in one embodiment, the combination DWC of the third timing driving waveform can be controlled so as to discharge a third discharge amount. The third discharge amount can be greater than the first discharge amount (the total amount of discharge amounts when discharge is performed from a plurality of nozzles NO).

[0105] For example, the third timing driving waveform combination DWC may include a twelfth driving waveform combination DW12, a thirteenth driving waveform combination DW13, a fourteenth driving waveform combination DW14, a fifteenth driving waveform combination DW15, a sixteenth driving waveform combination DW16 and a seventeenth driving waveform combination DW17.

[0106] For example, the combination DWC of the third timing driving waveform may include one driving waveform for controlling the discharge amount to be reduced by about 3% compared to the normal discharge amount and two driving waveforms for controlling the discharge amount to be increased by about 3% compared to the normal discharge amount. Thus, the total discharge amount generated by the combination DWC of the third timing driving waveform may be greater than the total discharge amount generated by the combination DWA of the first timing driving waveform.

[0107] For example, the twelfth drive waveform combination DW12, the thirteenth drive waveform combination DW13, the fourteenth drive waveform combination DW14, the fifteenth drive waveform combination DW15, the sixteenth drive waveform combination DW16, and the seventeenth drive waveform combination DW17 may each differ only in the order in which the drive waveforms are arranged.

[0108] However, the present invention is not limited to this. For example, the variable range of the discharge amount can be changed in various ways, and thus the combination DWC of the third timing drive waveform can also be varied.

[0109] but, Figures 8 to 10 This is merely an example, and the number and type of combinations of the plurality of driving waveforms may be varied in various ways.

[0110] refer to Figure 1 , Figure 8 and Fig.11 In one embodiment, nozzle groups NC corresponding to the combinations of the plurality of driving waveforms may be selected (step S500 ).

[0111] In one embodiment, the nozzle group NC may include nozzles (eg, a part of the plurality of nozzles NO) having an ejection amount (or a total amount of the ejection amounts) that satisfies an allowable error range of the target volume.

[0112] For example, multiple combinations of multiple drive waveforms (e.g., Figure 8 The combination of the first timing driving waveform DWA, Fig. 9 The combination of the second timing drive waveform DWB and Fig.10 The combination DWA of the first timing driving waveform can be selected from the combination DWC of the third timing driving waveform, and the combination DW1 of the first timing driving waveform can be selected from the combination DWA of the first timing driving waveform.

[0113] For example, when the target volume is about 40 pL and each of the plurality of nozzles N0 can discharge about 10 pL of ink IK, four nozzles (e.g., the first nozzle N1, the second nozzle N2, the third nozzle N3, and the fourth nozzle N4) may be selected from the six nozzles overlapping each of the plurality of pixel areas PXA. That is, the remaining two nozzles (e.g., the fifth nozzle N5) of the six nozzles may not discharge the ink IK.

[0114] In order to satisfy the combination DW1 of the first driving waveform, a driving waveform for controlling to discharge a normal discharge amount to each of the first nozzle N1, the second nozzle N2, the third nozzle N3, and the fourth nozzle N4 may be set. For example, a driving waveform for controlling to discharge about 10.22 pL of ink IK may be set for the first nozzle N1, a driving waveform for controlling to discharge about 9.72 pL of ink IK may be set for the second nozzle N2, a driving waveform for controlling to discharge about 9.80 pL of ink IK may be set for the third nozzle N3, and a driving waveform for controlling to discharge about 9.81 pL of ink IK may be set for the fourth nozzle N4.

[0115] Although in Fig.11 2 , the nozzle group NC is constituted by only the first row R1 and the second row R2 , but the present invention is not limited thereto. The plurality of nozzles NO included in the nozzle group NC may be selected in various ways within the range of the error tolerance of the target volume.

[0116] refer to Figure 1 , Figure 4 , Figure 8 , Fig. 9 , Fig.10 , Fig.11 , Fig.12 , Fig.13 , Fig.14 and Fig.15 In one embodiment, the combination of multiple driving waveforms may be changed for each pixel region in the multiple pixel regions PXA (eg, Figure 8 The combination of the first timing driving waveform DWA, Fig. 9 The combination of the second timing drive waveform DWB and Fig.10While any one of the third timing driving waveform combinations DWC) is being used, ink IK is ejected to a plurality of pixel areas PXA (step S600).

[0117] In one embodiment, the output part OP may output a control signal for changing a combination of a plurality of driving waveforms for each of the plurality of pixel areas PXA. The control signal may include a first control signal for selecting a combination of any driving waveform in the combination DWA of the first timing driving waveform, a second control signal for selecting a combination of any driving waveform in the combination DWB of the second timing driving waveform, and a third control signal for selecting a combination of any driving waveform in the combination DWC of the third timing driving waveform.

[0118] In one embodiment, a combination DWA of a first timing driving waveform may be applied in a first pixel region PX1 among the plurality of pixel regions PXA, and a combination DWB of a second timing driving waveform may be applied in a ninth pixel region PX9 adjacent to the first pixel region PX1. The first pixel region PX1 and the ninth pixel region PX9 may be adjacent to each other in a direction in which the plurality of nozzles NO move (i.e., a printing direction PD).

[0119] To this end, in one embodiment, the output unit OP may output (provide) a first control signal to each of the multiple nozzle columns RR so that a combination DWA of first timing drive waveforms is applied in the first pixel area PX1, and may output a second control signal to each of the multiple nozzle columns RR so that a combination DWB of second timing drive waveforms is applied in the ninth pixel area PX9.

[0120] For example, in one embodiment, in the first pixel area PX1 among the plurality of pixel areas PXA, Figure 8 The first driving waveform combination DW1 in the first timing driving waveform combination DWA is output to each nozzle column in the plurality of nozzle columns RR. In the ninth pixel area PX9, Fig. 9 The seventh driving waveform combination DW7 among the second timing driving waveform combinations DWB is output to each of the plurality of nozzle rows RR.

[0121] like Fig.14 As shown in FIG. 1 , the first pixel area PX1 and the ninth pixel area PX9 may be divided by a partition wall BK provided on the substrate SUB. The ink IK may be ejected into the opening defined by the partition wall BK to form a film. At this time, the ink IK may be ejected in a manner having an ejection amount within an error tolerance range OK of a target volume.

[0122] For example, the ink IK may include materials forming a common layer and a light-emitting layer included in an OLED panel, and the ink IK may also include materials forming a color conversion layer included in a QD-OLED panel. For example, the common layer and / or the light-emitting layer may each include an organic light-emitting material. The color conversion layer may include quantum dots. However, the present invention is not limited thereto. The ink IK may include a variety of materials that can be used in the process of manufacturing a display device.

[0123] For example, in the case where the combination DWA of the first timing driving waveform is set for the first pixel area PX1 and the combination DWB of the second timing driving waveform is set for the ninth pixel area PX9 , the height of the ink IK may be greater in the first pixel area PX1 .

[0124] In one embodiment, the combination DWB of the second timing driving waveform may be applied in the ninth pixel area PX9 among the plurality of pixel areas PXA, and the combination DWC of the third timing driving waveform may be applied in the seventeenth pixel area PX17 adjacent to the ninth pixel area PX9. The ninth pixel area PX9 and the seventeenth pixel area PX17 may be adjacent to each other in the direction in which the plurality of nozzles NO move (i.e., the printing direction PD).

[0125] To this end, in one embodiment, the output unit OP may output a second control signal to each of the multiple nozzle columns RR so that a combination DWB of second timing drive waveforms is applied in the ninth pixel area PX9, and may output a third control signal to each of the multiple nozzle columns RR so that a combination DWC of third timing drive waveforms is applied in the seventeenth pixel area PX17.

[0126] For example, in one embodiment, in a ninth pixel area PX9 among the plurality of pixel areas PXA, Fig. 9 The seventh driving waveform combination DW7 in the second timing driving waveform combination DWB is output to each nozzle column in the plurality of nozzle columns RR, and in the seventeenth pixel area PX17 which is most adjacent to the ninth pixel area PX9 along the printing direction PD, the seventh driving waveform combination DW7 in the second timing driving waveform combination DWB is output to each nozzle column in the plurality of nozzle columns RR, and ... the seventh driving waveform combination DW7 in the second timing driving waveform combination DWB is output to each nozzle column in Fig.10 A fifteenth drive waveform combination DW15 among the third timing drive waveform combination DWC is output to each of the plurality of nozzle columns RR.

[0127] like Fig.15 As illustrated in FIG. 1 , for example, when the combination DWB of the second timing driving waveform is set for the first pixel area PX1 and the combination DWC of the third timing driving waveform is set for the ninth pixel area PX9 , the height of the ink IK may be greater in the ninth pixel area PX9 .

[0128] Although in Fig.12 and Fig.13For example, when the printing direction PD is parallel to the second direction D2, the combination of driving waveforms applied to the first pixel area PX1 and the combination of driving waveforms applied to the second pixel area PX2 may be different from each other.

[0129] In addition, it is described that the plurality of nozzles NO provided in the plurality of nozzle arrays RR repeatedly eject the ink IK of the normal ejection amount and the ejection amount greater than the normal ejection amount, or repeatedly eject the ink IK of the normal ejection amount and the ejection amount less than the normal ejection amount for each of the plurality of pixel areas PXA along the printing direction PD, but the present invention is not limited thereto. For example, since it is sufficient that the ejection amount of each of the plurality of pixel areas PXA is different from each other, a plurality of combinations of a plurality of driving waveforms for controlling so that the ejection amount is ejected may be selected in a variety of ways.

[0130] In one embodiment, the combination of the driving waveforms may be changed so that the number of the combination DWB of the second timing driving waveform and the number of the combination DWC of the third timing driving waveform are the same. To this end, the output unit OP may change the combination of the plurality of driving waveforms so that the number of pixels to which the combination DWB of the second timing driving waveform is applied in the plurality of pixel areas PXA is the same as the number of pixels to which the combination DWC of the third timing driving waveform is applied in the plurality of pixel areas PXA.

[0131] For example, in the substrate SUB, a plurality of pixel areas PXA may be arranged in nine rows. In the case of setting the combination DWB of the second timing drive waveform four times (i.e., four rows out of nine rows), the combination DWC of the third timing drive waveform four times (i.e., four rows out of nine rows) may also be set, and the combination DWA of the first timing drive waveform may be set once (i.e., one row out of nine rows). However, the present invention is not limited thereto. The number of pixels to which the combination DWB of the second timing drive waveform is applied and the number of pixels to which the combination DWC of the third timing drive waveform is applied may also be different from each other.

[0132] In one embodiment, the combination of the driving waveforms may be changed so that the combination DWB of the second timing driving waveforms and the combination DWC of the third timing driving waveforms are adjacent. To this end, when the combination DWB of the second timing driving waveforms is set for any one pixel in the plurality of pixel areas PXA, the output unit OP may change the combination of the driving waveforms so that the combination DWC of the third timing driving waveforms is set for the next pixel. The any one pixel and the next pixel may be adjacent to each other with respect to the printing direction PD.

[0133] For example, when the combination DWB of the second timing driving waveform is set for any pixel in the plurality of pixel areas PXA, the combination DWC of the third timing driving waveform may be set for the next pixel. However, the present invention is not limited thereto. The combination of driving waveforms may also be changed so that the combination DWB of the second timing driving waveform and the combination DWC of the third timing driving waveform are not adjacent.

[0134] Fig.16 It is used to illustrate the previous reference Figures 5 to 15 A diagram illustrating the effect of the inkjet printing method.

[0135] For example, Fig.16 The display substrate PXM is manufactured by the inkjet printing method according to an embodiment of the present invention.

[0136] Multiple nozzles (e.g. Figure 1 Each of the plurality of nozzles NO) may produce an error in the ejection amount. Thus, a larger amount of ink than the error tolerance range of the target volume may be ejected (for example, Figure 1 Alternatively, the ink may be ejected in an amount less than the error tolerance range of the target volume.

[0137] In the case of the display substrate of the comparative example, it is impossible to perform the inkjet process while changing the combination of a plurality of driving waveforms for each of the plurality of pixel areas PXA, and streaks and spots may be generated.

[0138] However, reference Fig.16 If the inkjet printing method according to an embodiment of the present invention is applied, the generation of stripes and spots can be prevented in the display substrate PXM including a plurality of pixel areas PXA, thereby improving the display quality of the display device.

[0139] Industrial Applicability

[0140] The inkjet printing method and inkjet printer of exemplary embodiments of the present invention can be applied to the manufacturing process of display devices, which are included in computers (e.g., notebook computers), mobile phones, smart phones, smart tablets, portable media players (PMPs), personal digital assistants (PDAs), MP3 players, etc.

[0141] The above description refers to the embodiments of the present invention, but those skilled in the art will appreciate that the present invention can be modified and altered in many ways without departing from the scope of the invention and the scope of the invention described in the claims.

Claims

1. An inkjet printing method comprising the following steps: confirming the ink discharge amount of each of the plurality of nozzles arranged along the plurality of nozzle rows; setting a variable range of the ink ejection amount corresponding to each of the plurality of nozzle arrays; A plurality of combinations of a plurality of driving waveforms for performing control so as to discharge ink in different amounts from each other are set; as well as Ink is ejected to the plurality of pixel areas while changing a combination of the plurality of driving waveforms for each of the plurality of pixel areas.

2. The inkjet printing method according to claim 1, characterized in that: The variable range of the ink ejection amount is set within a range of -3% to +3% of the ink ejection amount of each of the plurality of nozzles.

3. The inkjet printing method according to claim 1, characterized in that: Before the step of setting the plurality of combinations of the plurality of driving waveforms, the method further comprises the following steps: A target volume for each of the plurality of pixel regions is input.

4. The inkjet printing method according to claim 3, characterized in that: After the step of setting the plurality of combinations of the plurality of driving waveforms, the method further comprises the following steps: A nozzle group including a part of the plurality of nozzles corresponding to the plurality of combinations of the plurality of driving waveforms, respectively, is selected.

5. The inkjet printing method according to any one of claims 1 to 4, characterized in that: The step of setting the plurality of combinations of the plurality of driving waveforms comprises: Setting a combination of first timing drive waveforms for performing control so as to discharge a first ink discharge amount; setting a combination of second timing drive waveforms for performing control so as to discharge a second ink discharge amount that is smaller than the first ink discharge amount; and A combination of third timing drive waveforms for performing control so as to discharge a third ink discharge amount larger than the first ink discharge amount is set.

6. The inkjet printing method according to claim 5, characterized in that: In the step of setting the plurality of combinations of the plurality of driving waveforms, The combination of the first timing driving waveforms and the combination of the second timing driving waveforms are each set to have a driving waveform different from each other for each of the plurality of nozzles included in each of the plurality of nozzle rows.

7. The inkjet printing method according to claim 5, characterized in that: In the step of discharging the ink while changing the combination of the plurality of driving waveforms for each of the plurality of pixel areas, The set number of combinations of the second timing driving waveforms is the same as the set number of combinations of the third timing driving waveforms.

8. The inkjet printing method according to claim 5, characterized in that: The step of changing the combination of the plurality of driving waveforms for each of the plurality of pixel areas and ejecting the ink to the plurality of pixel areas comprises: applying a combination of the second timing drive waveforms to the plurality of nozzles in a first pixel region among the plurality of pixel regions; and In a second pixel region among the plurality of pixel regions adjacent to the first pixel region in a moving direction of the plurality of nozzles, a combination of the third timing driving waveforms is applied to the plurality of nozzles.

9. The inkjet printing method according to claim 5, characterized in that: The step of changing the combination of the plurality of driving waveforms for each of the plurality of pixel areas and ejecting the ink to the plurality of pixel areas comprises: applying a combination of the first timing drive waveforms to the plurality of nozzles in a first pixel region among the plurality of pixel regions; and In a second pixel region among the plurality of pixel regions adjacent to the first pixel region in a moving direction of the plurality of nozzles, a combination of the second timing driving waveforms is applied to the plurality of nozzles.

10. The inkjet printing method according to claim 5, characterized in that: The step of changing the combination of the plurality of driving waveforms for each pixel area and ejecting the ink to the plurality of pixel areas comprises: applying a combination of the first timing drive waveforms to the plurality of nozzles in a first pixel region among the plurality of pixel regions; and In a second pixel region among the plurality of pixel regions adjacent to the first pixel region in a moving direction of the plurality of nozzles, a combination of the third timing driving waveforms is applied to the plurality of nozzles.

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