The invention will now be described with reference to the accompanying drawings, wherein like numbers refer to like elements.
Hereinafter, a preferred embodiment of the invention will be described in detail with reference to the accompanying drawings.
It should be noted that although the embodiments described below, which are preferable specific examples of the invention, are provided with various limitations technically preferable, the scope of the invention is not limited to these embodiments unless the description to limit the invention thereto is particularly presented in the following explanations. Further, the drawings referred to in the following explanations show some cases in which members or portions are shown with the different horizontal to vertical ratio from the actual ratio for the sake of illustration.
Droplet Discharging Device
Firstly, the configuration of the droplet discharging device will be explained with reference to
As shown in
On the main scanning movable stage 203 there is disposed a stage 205 for mounting a substrate P to be an discharging object. The stage 205 has a configuration capable of absorbing to fix the substrate P, and further, is configured to allow accurate adjustment of the reference axes in the substrate P to the main scanning direction and the sub-scanning direction with a rotary mechanism 207.
The sub-scanning movable stage 204 is provided with a carriage 209 attached thereto in a pendant manner via a rotary mechanism 208. Further, the carriage 209 is provided with a head unit 10 having discharging surface 10a for a liquid substance facing towards the substrate P, a liquid substance supplying mechanism (not shown) for supplying the head unit 10 with the liquid substance, and a control circuit board 211 (see
The head unit 10 is configured combining a plurality of droplet discharging heads 11 shown in
The nozzle plate 12 has a base plate 26 provided with through holes corresponding to the nozzles 20 and a surface layer 27 formed on the surface of the base plate 26. Further, a silicon substrate is used as the channel plate 13, a resin film is used as the flexible film 14, and a SUS plate is used as the upper cover plate 15.
The head unit 10 is provided with cavities 17 as liquid chambers connected to the respective nozzles 20 and a reservoir 18 as a reserving chamber of the liquid substance provided commonly to the plurality of cavities 17. Further, the liquid substance L supplied to the reservoir 18 via a flow channel not shown is supplied from the reservoir 18 to each of the cavities 17 and then to each of the nozzles 20. Inside each of the nozzles 20 supplied with the liquid substance L, a curved meniscus 25 is formed.
The nozzle 20 includes a first section bordering an opening surface 24 (discharging surface) and a second section bordering the liquid chamber, and has a straight section 22 formed linearly from the nozzle opening 21 as the first section and a tapered section 23 formed to have a tapered shape continuously to the straight section 22 as the second section. In the present embodiment, the inside diameter of the straight section is set to be 10 μm, the length thereof is set to be 20 μm, and the angle of spread of the taper section 23 is set to be 45 degrees. On the inside surface of the straight section 22, there is provided a recess section 30 as a meniscus regulating section formed as an area from which the surface layer 27 is eliminated. The recess section 30 according to the present embodiment is formed in a circular manner at the depth of 10 μm from the nozzle opening 21 along the inside circumferential direction of the straight section 22, and has a depth (corresponding to the thickness of the surface layer 27) of 1 μm.
On the opening surface 24 provided with the nozzle openings 21, there is formed a lyophobic film (not shown). As the lyophobic film, for example, a film (a self-assembly film) formed of chemical compound molecules having a lyophobic functional group such as fluoroalkylsilane bound each other on the opening surface 24 in an assembled condition, a coating formed as eutectoid (eutectic) of fluorocarbon resin, and so on can be used. This lyophobic plays a role of preventing the case that formation of the normal meniscus 25 is disturbed by the liquid substance adhering to the opening surface 24 spreading to wet around the nozzle opening 21.
In the upper cover section of the cavity 17, one end of the piezoelectric element 16 as meniscus moving means is bonded to the island section 15a movably disposed via the flexible film 14. As described above, by performing the control of the capacity and the liquid pressure in the cavity 17 by driving the piezoelectric element 16, the behavior (the shape and the position) of the meniscus 25 can be controlled. It should be noted that driving of the piezoelectric element 16 is performed by an electrical signal (hereinafter referred to as a drive signal) applied to the electrodes (not shown) of the piezoelectric element 16.
In
In response to the control computer 210 transmitting to the control circuit board 211 the drawing pattern data of the bitmap format representing the arrangement of the droplets on the substrate P (see
The nozzle data transmitted to the shift registers 50 is latched with the timing with which the latch signal (LAT) is input to the latch circuit 51, and further, converted to a gate signal for the switch 53 by the level shifter 52. Specifically, when the nozzle data is “ON,” the switch 53 opens to supply the piezoelectric element 16 with the drive signal (COM), and when the nozzle data is “OFF,” the switch 53 is closed, and no drive signal (COM) is supplied to the piezoelectric element 16. Further, in the nozzle 20 corresponding to the “ON” state, the control (hereinafter referred to as discharging control) of the meniscus 25 (see
In the configuration described above, the head unit 10 is moved (scanning) relatively with respect to the substrate P in the main scanning direction and the sub-scanning direction in the condition in which the relationship between the scanning direction and the arrangement direction of the nozzles 20 is accurately determined by the rotary mechanism 208. Further, the droplets are discharged from the nozzles 20 of the droplet discharging head 11 with appropriate timing in sync with the scanning by the head unit 10. Thus, it becomes possible to dispose the liquid substance at desired positions on the substrate P by a minute amount thereof. It should be noted that as the liquid substance, a liquid such as water or organic solvent, or various functional materials (e.g., metals, semiconductors, color materials, organic EL materials) dispersed or dissolved in such a liquid can be adopted in accordance with the usage.
Method of Manufacturing Nozzle Plate
Then, a method of manufacturing the nozzle plate will be explained with reference to
Firstly, as shown in
Subsequently, as shown in
Subsequently, as shown in
Subsequently, as shown in
It should be noted that by repeating the control of the amount of insertion of the resist film 31 described above and the selective formation and etching of the surface layer 27, a plurality of recess sections 30 can also be formed at different depth positions. Further, as another method of forming the recess section 30, the plating method performed while precisely controlling the dipping depth in the plating liquid can also be considered.
Discharging Control Method
Then, the discharging control method for the droplet discharging head will be explained with reference to
The drive signal (COM) shown in
The pulse group PS includes a charge pulse p1 for raising the electrical potential, discharge pulses p3, p5 for lowering the electrical potential, and horizontal pulses p2, p4 for connecting these pulses and keeping the electrical potential constant. In the time duration before the pulse group PS is applied, the meniscus 25 in the nozzle 20 is positioned slightly in the back of the nozzle opening 21 (hereinafter, the position is referred to as a stationary position).
If the cavity 17 is depressurized in accordance with the application of the charge pulse p1, the meniscus 25 is deeply pulled in towards the inside (the direction towards the taper section 23 (see
When the cavity 17 is pressurized in response to application of the steep discharge pulse p3 through the horizontal pulse p2, the meniscus 25 is pushed out towards the nozzle opening 21, and the center portion 25b of the meniscus 25 protrudes outward from the nozzle opening 21. (step B). The center portion 25b of the meniscus 25 is eventually separated from the liquid substance L in the nozzle 20 by the force thereof, and is discharged as a droplet.
The discharge pulse p5 plays a role of returning the electrical potential at the end of the discharge pulse p3 (the horizontal pulse p4) to the electrical potential at the beginning of the pulse group PS. Further, the discharge pulse p5 is designed to be applied with the timing for canceling the residual vibration in order for playing a role of attenuating early the pressure oscillation (residual vibration) inside the cavity 17 and the nozzle 20 caused by the charge pulse p1 and the discharge pulse p3.
In the discharging control described above, the position of the meniscus 25 after applying the charge pulse p1, namely the discharging standby position is an element having a strong relationship with the amount (discharging amount) of the droplet to be discharged. For example, if the discharging standby position is nearer to the inside of the nozzle 20, the discharging amount is relatively reduced, and if the discharging standby position is nearer to the nozzle opening 21, the discharging amount is relatively increased. In other words, it is an important matter for performing the stable discharging control to stabilize the discharging standby position.
The recess section 30 in the nozzle 20 according to the present embodiment is provided in view of such circumstances, and plays a role of regulating moving of the edge 25a of the meniscus 25 in that position (depth) when the meniscus 25 is pulled in, and thus stabilizing the discharging standby position. In the discharging control of such a droplet discharging head 11, it is preferable to appropriately design the strength of the charge pulse p1 so that the edge 25a of the meniscus 25 after applying the charge pulse p1 is positioned at the forming position (depth) of the recess section 30. Further, in the resent embodiment, it is arranged that the movement of the edge 25a of the meniscus 25 is regulated in an isotropic manner by providing the recess section 30 in a circular manner along the inside circumferential direction of the nozzle 20, thus making consideration of not giving bad influence to the shape of the meniscus 25.
Now, a modified example will be explained focusing on the differences from the previous embodiment with reference to
As shown in
Firstly, as shown in
Subsequently, as shown in
Subsequently, as shown in
It should be noted that as an application of the process described above, by forming a self-assembling film such as fluoroalkylsilane instead of the surface layer 27 and performing a surface activation process by, for example, Ar plasma irradiation instead of etching, the area corresponding to the protruding section 33 can be made lyophobic, and the area irradiated by the Ar plasma can be made lyophilic. In the nozzle 20 provided with such lyophobic area (lyophobic film), the movement of the edge of the meniscus is also regulated by the boundary between the lyophobic area and the lyophilic area when the meniscus is pulled in, in other words, the meniscus regulating section of the present modified example can be formed also by such a lyophobic area.
As explained hereinabove, the structure, the shape, and so on of the meniscus regulating section according to the embodiments of the invention are not particularly limited providing the meniscus regulating section can regulate the movement of the edge of the meniscus in the inside wall of the nozzle. For example, such a modification as forming the recess section 30 (see
Now, a second embodiment will be explained focusing on the differences from the first embodiment with reference to
As shown in
In the first control mode, when the charge pulse p11 is applied, the meniscus 25 is largely pulled in towards the inside of the nozzle 20 from the stationary position (step A1). In this case, the position (depth) of the edge 25a of the meniscus 25 becomes the position (depth) at which the first recess section 41 is formed, and the droplet is discharged in response to application of the subsequent discharge pulse p13 (step B1).
In the second control mode, when the charge pulse p21 is applied, the meniscus 25 is largely pulled in towards the inside of the nozzle 20 from the stationary position (step A2). The charge pulse p21 is arranged sufficiently large compared to the charge pulse p11 according to the first control mode, and in this case, the edge 25a of the meniscus 25 is pulled in deeper in the back beyond the position (depth) of the first recess section 41, and the movement thereof is regulated at the position of the second recess section 42. Then, the droplet is discharged by application of the subsequent discharge pulse p23 (step B2).
In comparison of the discharging amounts in both of the modes, reflecting the difference in the discharging standby positions of the meniscus 25, the discharging amount according to the second control mode becomes smaller than the discharging amount according to the first control mode. As described hereinabove, according to the second embodiment provided with the meniscus regulating sections at different depths inside the nozzle, it is arranged that the discharging control with high stability can be achieved by the stabilization of the discharging standby positions, and in addition, the discharging amount can be varied in accordance with the modes.
It should be noted that it can be arranged that the first control mode drive signal (COM1) and the second control mode drive signal (COM2) are supplied to the piezoelectric element 16 (see
The invention is not limited to the embodiments described above. Each of the components of the embodiments can be combined with each other appropriately, eliminated, or combined with other components not shown.
Number | Date | Country | Kind |
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2006-198045 | Jul 2006 | JP | national |