Abstract:
An ink-jet system and an ink-jet control method are provided. The ink-jet system mainly includes an ink-jet head, a feedback unit and a frequency eliminator. The feedback unit provides a feedback signal to the ink-jet head as the ink-jet head performs jet printing. Next, the frequency of the feedback signal is eliminated by the frequency eliminator to produce a driving signal. Then, the ink-jet head is controlled to perform ink-jetting according to the driving signal. The frequency of the feedback signal is higher than that of the driving signal, and the frequency of the feedback signal is divisible by that of the driving signal. The ink-jet system and the ink-jet control method meets high precision and high speed ink-jet requirements and are capable of fabricating patterns with different resolutions.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority benefit of Taiwan application serial no. 95126651, filed Jul. 21, 2006. All disclosure of the Taiwan application is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of Invention 
         [0003]    The present invention relates to an ink-jet system and an ink-jet control method, and more particularly, to an ink-jet system and an ink-jet control method that are capable of quickly and exactly controlling the ink-jet speed. 
         [0004]    2. Description of Related Art 
         [0005]    As the progress of the fabricating process technique, the ink-jetting technique has been widely applied to fabricate various precise elements, such as liquid crystal display, semiconductor element and packaging element (e.g., printed circuit board), based on the advantage that it can be used to fabricate highly precise patterns. 
         [0006]    Conventional ink-jet techniques are generally applied to the printer to print pictures or other image outputs. Under the precondition that the quality of the output picture has met with the requirements of the human eyes, it focuses on enhancing the printing speed. Compared with the previous ink-jetting technique, the ink-jetting technique currently used in the industry requires an ink-jet controlling with a precise positioning effect and a high printing speed, in order to output precise patterns and satisfy the production efficiency. 
         [0007]      FIG. 1  is a conventional ink-jet technique control method. As shown in  FIG. 1 , when a motion control is performed to an ink-jet printing platform, a feedback unit such as an optical scale or a rotary encoder outputs a triggering signal  110  to a control chip of the ink-jet head, so as to control a nozzle on the ink-jet head to perform ink-jetting. Generally speaking, the moving speed of the ink-jet printing platform and the speed of ink-jetting must be balanced, that is, the frequency of the triggering signal  110  generated while the ink-jet printing platform moves is required to be smaller than or equal to the maximum operating frequency of the ink-jet controlling, otherwise, the quality of the ink-jetting may be deteriorated. 
         [0008]    On the other aspect, if the motion control with a high resolution is selected to make the frequency of the triggering signal be higher than the desired operating frequency of the ink-jet control, the ink-jet head and the triggering signal  110  perform triggering synchronously, such that each pulse signal input to the control chip needs to be processed, and accordingly the processing speed of the control chip is relatively slowed down, thereby affecting the ink-jetting quality and speed. In other words, the moving speed of the ink-jet printing platform is limited by the ink-jet frequency. 
         [0009]    Recently, the common method is to employ the triggering signal with a relatively low motion resolution. In  FIG. 1 , a triggering signal  110  with a relatively low motion resolution, for example, 30 μm, is selected to form the ink-jet pattern with a relatively high resolution (e.g., 10 μm). The mark  120  represents an ink-jet control signal of the ink-jet head, wherein besides the circumstance that the triggering point  122  performs the synchronous triggering according to the triggering signal  110 , the following triggering points  124 ,  126  must be selected through the time slicing between two pulses of the triggering signal  110  performed by the circuit control. As shown in  FIG. 1 , in order to generate the ink spots with equal intervals, the triggering points of the triggering signal  110  must be spaced with equal intervals. However, since the motion control of the ink-jet printing platform is of a low resolution, and the circuit control is used to select the asynchronously triggered triggering points  124 ,  126 , the triggering points  124 ,  126  may generate offsets, and the correspondingly generated ink spots are not located on desired positions, so as to result in the non-uniformity of the ink-jetting and defects of the ink-jet pattern, and thereby resulting in the reducing of the yields of the process. 
         [0010]    The mark  130  in  FIG. 1  represents the distribution of desired ink spot, wherein the ink spots  132 ,  134  and  136  respectively correspond to the triggering points  122 ,  124  and  126 , and under the ideal state, a successive and uniform ink-jet pattern  152  is formed. Correspondingly, the mark  140  in  FIG. 1  represents the distribution of actual ink spot, wherein actually only the ink spot  142  that is synchronously triggered with the triggering point  122  is located on the correct position. Since the low resolution motion control of the ink-jet printing platform may result in the shifting of the triggering points  124 ,  126 , the corresponding ink spots  144  and  146  may offset from the desired positions, so as to form the ink-jet patterns  154  or  156  with defects. 
         [0011]    To sum up, the current ink-jet control technique is still restricted by the mutual restrain of the motion resolution and the ink-jet speed of the ink-jet printing platform, such that it is impossible to achieve the optimized ink-jet control with high precision and high speed. 
       SUMMARY OF THE INVENTION 
       [0012]    The present invention is directed to an ink-jet control method, which meets with high precision and high speed ink-jet requirements and is capable of fabricating patterns with different resolutions. 
         [0013]    The present invention is further directed to an ink-jet system, which achieves a high precision and high speed ink-jet control and is capable of fabricating patterns with different resolutions, so it has a relatively high compatibility. 
         [0014]    As embodied and broadly described herein, the present invention provides an ink-jet control method, which is suitable for controlling an ink-jet head to perform ink-jetting. In the ink-jet control method, firstly, a feedback signal is provided to the ink-jet head, and then, a driving signal is generated according to the feedback signal. The frequency of the feedback signal is higher than that of the driving signal, and the frequency of the feedback signal is divisible by that of the driving signal. Finally, the ink-jet head is controlled to perform ink-jetting according to the driving signal. 
         [0015]    In an embodiment of the present invention, the method of generating the driving signal is that, for example, a flip-flop device or a counter is used to perform a frequency eliminating on the feedback signal. 
         [0016]    In an embodiment of the present invention, the feedback signal is generated from a function generator, an optical scale or a rotary encoder that performs the feedback control to the ink-jet head. 
         [0017]    In an embodiment of the present invention, the ink-jet head has a nozzle, and after receiving the driving signal, the ink-jet head outputs an ink-jet control signal to the nozzle according to the driving signal. 
         [0018]    In an embodiment of the present invention, the ink-jet head has a plurality of nozzles, and after receiving the driving signal, the ink-jet head outputs an ink-jet control signal to each nozzle respectively according to the driving signal. 
         [0019]    In an embodiment of the present invention, the ink-jet control signals are synchronized or not synchronized with the driving signal. Moreover, the ink-jet control signals have the same or different phase difference with respect to the driving signal. 
         [0020]    In an embodiment of the present invention, when the ink-jet head outputs the ink-jet control signal according to the driving signal, the method further comprises modulating at least one ink-jet control signal, wherein the performed modulation is, for example, an addressable pulse width modulation. 
         [0021]    In an embodiment of the present invention, wave forms of the feedback signal, the driving signal and the ink-jet control signal are, for example, a square wave, a sine wave, a triangular wave, a trapezoidal wave or any combination thereof. 
         [0022]    The present invention further provides an ink-jet system, which mainly comprises an ink-jet head, a feedback unit and a frequency eliminator. When the ink-jet head performs the ink-jet printing, the feedback unit provides a feedback signal. The frequency eliminator performs the frequency eliminating to the feedback signal and generates a driving signal. Thus, the ink-jet head is controlled to perform ink-jetting according on the driving signal. The frequency of the feedback signal is higher than that of the driving signal, and the frequency of the feedback signal is divisible by that of the driving signal. 
         [0023]    In an embodiment of the present invention, the feedback unit is, for example, a function generator, an optical scale or a rotary encoder. 
         [0024]    In an embodiment of the present invention, the frequency eliminator is, for example, a flip-flop device or a counter. 
         [0025]    In an embodiment of the present invention, the ink-jet head has a nozzle, and after receiving the driving signal, the ink-jet head outputs an ink-jet control signal to the nozzle according to the driving signal. In an embodiment of the present invention, the ink-jet head has a plurality of nozzles, and after receiving the driving signal, the ink-jet head outputs an ink-jet control signal to each nozzle respectively according to the driving signal. 
         [0026]    In an embodiment of the present invention, the ink-jet control signals are synchronized or not synchronized with the driving signal. Moreover, the ink-jet control signals have the same or different phase difference with respect to the driving signal. 
         [0027]    In an embodiment of the present invention, the ink-jet head further has a modulating unit for modulating at least one ink-jet control signal when outputting the ink-jet control signals. The modulating unit is, for example, an addressable pulse width modulation unit. 
         [0028]    In an embodiment of the present invention, wave forms of the feedback signal, the driving signal and the ink-jet control signal are, for example, a square wave, a sine wave, a triangular wave, a trapezoidal wave or any combination thereof. 
         [0029]    Based on the above, after the feedback signal is generated in the present invention, firstly, the frequency eliminating is performed to the feedback signal, so as to obtain a driving signal with a desired triggering frequency, and thereby driving the ink-jet head to perform the ink-jetting according to the driving signal. Therefore, each ink spot corresponds to a triggering point of the driving signal, so as to achieve the requirements of the accurate position of the ink spot. Moreover, the frequency eliminating process can be used to avoid the problem of a low processing speed of the chip caused by the excessively high frequency of the triggering signal under the high resolution motion control, so as to be helpful for enhancing the ink-jet speed. 
         [0030]    In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]    The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
           [0032]      FIG. 1  is a conventional common ink-jetting technique control method. 
           [0033]      FIG. 2  is a block diagram of an ink-jet system according to a preferred embodiment of the present invention. 
           [0034]      FIG. 3  shows an ink-jet control method of the present invention that is suitable for being used in the ink-jet system. 
           [0035]      FIG. 4  shows a corresponding relationship between the signal and the ink-jet pattern in an ink-jet control method of the present invention. 
           [0036]      FIG. 5  shows a corresponding relationship between the signal and the ink-jet pattern in another ink-jet control method of the present invention. 
           [0037]      FIGS. 6A and 6B  show a corresponding relationship between the signal and the ink-jet pattern in still another ink-jet control method according to the present invention. 
           [0038]      FIGS. 7 and 8  respectively show a block diagram and an ink-jet control method of the ink-jet system suitable for the driving method of  FIG. 6B . 
           [0039]      FIGS. 9A and 9B  show a corresponding relationship between the signal and the ink-jet pattern in yet another ink-jet control method of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0040]      FIG. 2  is a block diagram of an ink-jet system according to a preferred embodiment of the present invention. As shown in  FIG. 2 , the ink-jet system  200  mainly includes an ink-jet head  210 , a feedback unit  220  and a frequency eliminator  230 . The ink-jet head  210  has at least one nozzle, and in the embodiment, the ink-jet head  210  having three nozzles  212 ,  214  and  216  is taken as an example. Moreover, the ink-jet head  210  has a control chip  218  for controlling the nozzles  212 ,  214  and  216  to perform the ink-jetting. The feedback unit  220  is coupled to the ink-jet system  200 , so as to provide a feedback signal  310  to the ink-jet head  210 . The frequency eliminator  230  is coupled between the feedback unit  220  and the control chip  218  of the ink-jet head  210 , so as to perform the frequency eliminating on the feedback signal F, and to output a driving signal D to the control chip  218 , and thereby controlling the ink-jet head  210  to perform the ink-jetting. 
         [0041]    Referring to  FIG. 2  and  FIG. 3 ,  FIG. 3  shows an ink-jet control method of the present invention that is suitable for being used in the ink-jet system. When performing the ink-jet control, firstly, the ink-jet head  210  receives a position feedback signal (step  310 ). In the embodiment, the feedback unit  220  is used to read the ink-jet printing position of the ink-jet head  210 , wherein the adopted feedback unit  220  is, for example, a function generator, an optical scale or a rotary encoder, and used for outputting a corresponding feedback signal F to the frequency eliminator  230  according to the ink-jet printing position of the ink-jet head  210 . 
         [0042]    Next, as shown in step  320 , the frequency eliminator  230  is used to perform the frequency eliminating to the feedback signal F, so as to generate a driving signal D according to the feedback signal F, wherein the frequency of the feedback signal F needs to be higher than that of the driving signal D, and the frequency of the feedback signal F is divisible by that of the driving signal D. In the present invention, the frequency eliminator  230  is a flip-flop device, a counter or other known circuits or elements that can achieve the same effect. The frequency eliminating step mainly aims at changing the feedback signal F with a relatively high frequency to a triggering clock with a relatively low frequency and then outputting the feedback signal F, wherein the frequency of the triggering clock is the desired ink-jetting frequency. Therefore, in the present invention, the driving signal D with an appropriate triggering clock may be obtained through the frequency eliminating operation according to the required pattern resolution. It should be noted that, the frequency of the feedback signal F depends on the ink-jet printing resolution of the feedback unit  220  when the ink-jet head  210  performs the ink-jet printing. As for selecting the resolution of the feedback unit  220 , the desired operating frequency, the pattern resolution and the cost of the ink-jet control should be considered. 
         [0043]    Then, as shown in step  330 , after receiving the driving signal D, the control chip  218  of the ink-jet head  210  controls the ink-jet head  210  to perform the ink-jetting. Particularly, the ink-jet head  210  having three nozzles  212 ,  212  and  216  is taken as an example in the embodiment, and the control chip  218  outputs the ink-jet control signals T 1 , T 2  and T 3  to the corresponding nozzles  212 ,  214  and  216  according to the driving signal D, so as to control the nozzles  212 ,  214  and  216  to perform the ink-jetting. 
         [0044]    The feedback signal F, the driving signal D and the ink-jet control signals T 1 -T 3  are pulse signals, and their wave forms may be a square wave, a sine wave, a triangular wave, a trapezoidal wave or any combination thereof, which is not limited in the present invention. 
         [0045]    The corresponding relationship between the signal and the ink-jet pattern in an ink-jet control method of the present invention is further demonstrated below with reference to  FIG. 4 . As shown in  FIG. 4 , in order to be used in the subsequent frequency eliminating operation, the feedback unit with a relatively high resolution is selected in the embodiment, so as to generate a high frequency feedback signal  410  according to the ink-jet printing position of the ink-jet head, and the resolution of the feedback signal  410  generated by way of the position control is, for example, only about 2 μm. If it is intended to obtain ink spots with an interval of 10 μm the same as that of the conventional art, the driving signal  420  with a relatively low frequency is obtained through the frequency eliminating in the embodiment, wherein the frequency is ⅕ of that of the feedback signal  410 , that is, the period of the driving signal  420  is 5 times of that of the feedback signal  410 . Then, after the driving signal  420  has been inputted into the control chip of the ink-jet head, the ink-jet control signal  430  being synchronized with the driving signal  420  is output according to the driving signal  420 , so as to control the nozzle of the ink-jet head to perform the ink-jetting, thus, ink spots with an adjacent interval of 10 μm is obtained. In the embodiment, each ink spots  442 ,  444  and  446  are synchronized with the feedback signal  410  to correspond to the pulse of the feedback signal  410  exactly, so as to obtain the accurate ink-jet position, and thereby forming a uniform ink-jet pattern  452 . 
         [0046]      FIG. 5  shows a corresponding relationship between the signal and the ink-jet pattern in another ink-jet control method of the present invention. In the embodiment, each ink-jet head has a plurality of nozzles, for example, nozzles A and B, so after a feedback signal  510  has been received and then the frequency eliminating operation has been performed to the feedback signal  510  to obtain a driving signal  520 , the control chip of the ink-jet head outputs ink-jet control signals  530 A and  530 B to the nozzles A and B respectively according to the driving signal  520 , so as to control the nozzles A and B respectively to perform the ink-jetting. Similar to the above embodiment, the resolution of the feedback signal  510  is also set to be 2 μm in the embodiment, and the frequency of the driving signal  520  and the ink-jet control signals  530 A,  530 B is ⅕ of that of the feedback signal  510 , so as to obtain ink spots  542 A,  544 A,  546 A and  542 B,  544 B,  546 B with the adjacent interval of 10 μm. 
         [0047]    It should be noted that, due to the defects in the manufacturing process of the ink-jet head or the variation of the temperature and the pressure in the process of the ink-jet control, under the same driving control, the ink spots generated by different nozzles are different in size.  FIG. 6A  is a schematic view showing that when the ink-jet control method is adopted, the ink spots with different sizes are generated due to the defects of the ink-jet head. In order to solve the above problems, the individual ink-jet control signal corresponding to each nozzle can further be modulated in the present invention. 
         [0048]      FIG. 6B  shows a corresponding relationship between the signal and the ink-jet pattern after the ink-jet control method of  FIG. 6A  has been improved. Referring to  FIGS. 6A and 6B , after a feedback signal  610  has been received and then the frequency eliminating operation has been performed to the feedback signal  610  to obtain a driving signal  620 , the control chip of the ink-jet head outputs ink-jet control signals  630 A and  630 B respectively according to the driving signal  620 . As shown in  FIG. 6A , if the same ink-jet control signals  630 A and  630 B have been received, ink spots  642 A,  644 A,  646 A generated by the nozzle A are larger than ink spots  642 B,  644 B,  646 B generated by the nozzle B. Therefore, as shown in  FIG. 6B , an addressable pulse width modulation is performed to the ink-jet control signal  630 B in the embodiment, so as to obtain an ink-jet control signal  630 B′ with a larger pulse width. Therefore, the ink-jet control signal  630 B′ may be used to prolong the ink-jetting time of the nozzle B. In other words, the size of the ink spots  642 B′,  644 B′,  646 B′ generated by the nozzle B may be adjusted to be equal to that of the ink spots  642 A,  644 A,  646 A generated by the nozzle A. 
         [0049]      FIGS. 7 and 8  respectively show a block diagram and an ink-jet control method of an ink-jet system that is suitable for the driving method. As shown in  FIGS. 7 and 8 , an ink-jet system  700  mainly includes an ink-jet head  710 , a feedback unit  720  and a frequency eliminator  730 , wherein the ink-jet system  700  is similar to the ink-jet system  200  of  FIG. 2 , and a part of the components can be obtained with reference to the descriptions of  FIG. 2 , which thus will not described herein any more. The feedback unit  720  is coupled to the ink-jet head  710 , and as shown in step  810 , the feedback unit  720  outputs a corresponding feedback signal F to the frequency eliminator  730  according to the ink-jet printing position of the ink-jet head  710 . Then, as shown in step  820 , the frequency eliminator  730  performs the frequency eliminating to the feedback signal F, so as to generate a driving signal D according to the feedback signal F, and then transmits the driving signal D to the control chip  718  of the ink-jet head  710 . The frequency of the feedback signal F is higher than that of the driving signal D, and the frequency of the feedback signal F is divisible by that of the driving signal D. Then, as shown in step  830 , after receiving the driving signal D, the control chip  718  outputs ink-jet control signals T 1 , T 2  and T 3  respectively, and as shown in step  840 , the addressable pulse width modulation unit  719  is used to modulate at least one of the ink-jet control signals T 1 , T 2  and T 3 , so as to obtain modulated ink-jet control signals T 1 ′, T 2 ′ and T 3 ′. Then, as shown in step  850 , the ink-jet control signals T 1 ′, T 2 ′ and T 3 ′ are output to the corresponding nozzles  712 ,  714  and  716 , so as to control the nozzles  712 ,  714  and  716  to perform the ink-jetting. 
         [0050]      FIG. 9A  shows a corresponding relationship between the signal and the ink-jet pattern in yet another ink-jet control method of the present invention. The control method adopted in the embodiment may not trigger all the nozzles on the same time, according to the asynchronous controlling requirements between different nozzles, e.g., the ink-jet controls in scan driving or changing of the ink-jet positions. To meet the above requirements, in the embodiment, for example, firstly, the feedback signal  910  is received; and then, the frequency eliminating operation is performed to the feedback signal  910 , so as to obtain a driving signal  920 ; then, according to the driving signal  920 , the ink-jet control signals  930 A and  930 B are asynchronously output in sequence to the nozzles A and B, wherein the ink-jet control signal  930 A is synchronized with the driving signal  920 , and the ink-jet control signal  930 B has a phase difference ΔP with respect to the driving signal  920 , so as to control the nozzles A and B in sequence to perform the ink-jetting. It should be noted that, the ink-jet control signals  930 A and  930 B of the embodiment are still synchronized with the feedback signal  910 . 
         [0051]    Moreover, if the above embodiment is combined with the ink-jet control method of  FIGS. 6A and 6B , a corresponding relationship between the signal and the ink-jet pattern of another ink-jet control method is further obtained as shown in  FIG. 9B . In the embodiment, besides the circumstance that the ink-jet control signals  930 A and  930 B are output asynchronously, the addressable pulse width modulation is performed to the ink-jet control signal  930 B, so as to output an ink-jet control signal  930 B′ with a relatively large pulse width. In this manner, the size of the ink spots formed by the nozzles A and B may be adjusted to make up for the printing problems caused by the manufacturing process defects. 
         [0052]    Moreover, only two ink-jet control signals are taken as an example in the above embodiment, but if the ink-jet head has more than three nozzles, and more than three ink-jet control signals are applied, each ink-jet control signal may have the same or different phase difference with respect to the driving signal depending upon the designing requirements, which thus will not be described herein any more. 
         [0053]    To sum up, the ink-jet control method and the ink-jet system of the present invention at least have the following features and advantages. 
         [0054]    First, the frequency eliminating operation is performed to the feedback signal that controls the motion of the ink-jet head, so as to obtain the driving signal that is in accordance with the desired triggering frequency, thus, the problem of the slow processing speed of the chip caused by the excessively high frequency of the triggering signal under the high resolution motion control may be solved, so as to be helpful for enhancing the ink-jetting speed. 
         [0055]    Second, the driving signals with different frequencies are obtained through the frequency eliminating according to the feedback signal, so as to satisfy different printing requirements, and thereby having a preferred compatibility. 
         [0056]    Third, each ink spot corresponds to one triggering point of the driving signal, so as to meet the accurate requirements about the positions of the ink spots, which is helpful for enhancing the ink-jetting quality. 
         [0057]    Fourth, due to the manufacturing process defects or the variations of the temperature and the pressure in the process of the ink-jet control, the ink-jet control signal corresponding to the nozzle is modulated, so as to change the size of the ink spot and thereby further enhancing the quality of the ink-jet pattern. 
         [0058]    Fifth, the ink-jet control signals for different nozzles are output asynchronously to trigger the nozzles at different time, so as to meet the printing requirements such as the ink-jet control in scan driving or changing of the ink-jet positions. 
         [0059]    It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.