Patent Application
20090167816
1. Field of the Invention
The present invention relates to ink jet methods and, particularly, to an ink jet method that functions to form a patterned layer on a substrate.
2. Description of Related Art
In order to manufacture a patterned layer on a substrate, an ink jet method is used. This method is more economic than the traditional photolithographic method, since less waste materials and less manufacturing steps. Ink jet technology employing ink jet heads can be used, e.g., for printing of color filters. In order to implement the ink jet method, an ink jet system with a plurality of ink jet heads for jetting ink droplets was developed. Each ink jet head includes an ink chamber, a pressure-generating element (e.g., a piezo-electric element), and a nozzle face with an opening (i.e., a nozzle). The ink chamber is configured (i.e., structured and arranged) for temporary ink storage, whereby the ink is supplied from an external device. The pressure-generating element functions as a driving force for jetting a specific amount of ink stored in the ink chamber. The nozzle face has an opening, through which ink droplets are jetted from the ink chamber.
However, the ink in the opening of the nozzles may harden/dry and thereby clog the respective nozzles, if the ink jet head is left unused for a long time. Conventionally, a capping component is used to seal the ink jet head, so as to prevent the ink from hardening. However, the capping component usually cannot prevent at least some amount of ink from hardening. As a result, an amount of hardening that does occur that may adversely affect functioning of the ink jet head.
What is necessary, therefore, is to provide an ink jet method that can, more efficiently, prevent the nozzles from clogging.
In a present embodiment, an ink jet method for forming respective patterned layers on separate substrates includes these following steps:
Step 1: providing an ink jet system and at least one substrate, the ink jet system including an ink jet head module, the ink jet head module containing a plurality of nozzles;
Step 2: jetting ink from the nozzles onto a given substrate to form a patterned layer onto the given substrate;
Step 3: removing the given substrate with the patterned layer formed thereon;
Step 4: making the liquid level of the ink in the nozzle changed within each predetermined time interval during/over the course of a predetermined amount of time.
Other advantages and novel features of the present invention will become more apparent from the following detailed description of the at least one present embodiment when taken in conjunction with the accompanying drawings.
Many aspects of the present ink jet method can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present ink jet method. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Reference will now be made to the drawings to describe the present embodiments of the present inkjet method, in detail.
Referring to
The ink receiver 106 can be an object that contain or absorb the ink. In the present embodiments, the ink receiver 106 is used for containing ink jetted from the ink jet head module 104, when the ink jet head module 104 is at/in a non-working state. In this present embodiment, the ink receiver 106 is disposed on the worktable 102. The waste liquid container 108 is connected with the ink receiver 106 by a guide pipe 120, and the ink in the receiver 106 can be guided into the waste liquid container 108. It is to be understood that a means (not shown) may be provided to permit ink received in the waste liquid container 108 to be recycled (e.g., transferred back to the ink supply tank (not shown) to be re-used for ink jetting and/or collected for other use). It is to be further understood that, e.g., three separate waste liquid containers 108 to separately capture three different inks for recycling. Of course, the ink receiver 106 also can be replaced by sponge to absorb the ink and the waste liquid container 108 is omitted.
The ink jet system 100 also includes a guide rail 116. In order to drive the ink jet head module 104 moving over the substrate 114 and over the ink receiver 106, the ink jet head driving device 110 is configured to drive the ink jet head module 104 along the rail mechanism 116. The ink jet controlling device 112 is configured to control jetting quantity and the frequency of the ink jet head module 104. Generally, the ink jet head driving device 110 can, beneficially, be a motor device. Besides, if the inkjet head module 104 is stationary, the work table will be moved so that the ink jet head module 104 is located over the ink receiver 106.
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It is to be understood that any number of ink jet heads 118 (e.g., one, two, four, five, etc.) can be present in a given ink jet head module 104. Also, the number of the nozzles 1182 within a given ink jet head 118 can be more or less than eight and still be within the scope of the present embodiment.
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Step 202: providing the ink jet system 100 and at least one substrate 114. A given substrate 114 is disposed on the worktable 102, and the ink jet head module 104 is placed over the given substrate 114.
Step 204: jetting ink from the ink jet head module 104 onto the substrate 114 to form a given patterned layer on the given substrate 114, in order to form, e.g., a color filter, an electroluminescent apparatus, a polymer light emitting diode, or another electro-optical apparatus.
Step 206: removing the given substrate 114, with the given patterned layer formed thereon;
Step 208: optionally, providing another substrate 114, and repeating the Steps 204 and 206 until a predetermined number of substrates 114 have respective patterned layers formed thereon;
Step 210: making the liquid level of the ink 1184 in the nozzle 1182 changed within each predetermined time interval during/within a given predetermined time, in order to prevent the nozzles 1182 from experiencing clogs in the respective openings thereof due to adhesion of hardened/dried ink. In the present embodiment, the change of the liquid level of the ink 1184 is done by the pressure generated by the pressure-generating element (e.g., a piezo-electric element) inside the ink jet head 118. The change of the liquid level of the ink 1184 may cause the liquid level to vibrate or the ink 1184 to jet from the nozzle 1182. The predetermined time interval may vary depending on the material (i.e., composition) of the ink 1184. In general, if the ink 1184 contains a solvent with a higher boiling point (i.e., likely having a relatively low viscosity at room temperature, as well), advantageously, the predetermined time interval is longer. In an alternative scenario, if the ink 1184 contains a solvent with a boiling point that is fairly low (i.e., likely having a relatively high viscosity at room temperature, as well), usefully, the predetermined time interval may be shorter. For example, if a boiling point B1 of the solvent, in the ink 1184, is in a range B1<100° C., the predetermined time interval T1 is roughly in a range of 20 seconds to 5 minutes. Preferably, the predetermined time interval T1 is roughly in a range of 30 seconds to 2.5 minutes. In another example, if a boiling point B2 of the solvent in the ink 1184 is in a range B2>180° C., the predetermined time interval T2 is roughly in a range of 1 minutes to 5 minutes. Preferably, the predetermined time interval T2 is roughly in a range of 1 minute to 3 minutes.
In the present embodiment, Step 210 also can be replaced by a Step 210′ described as below: causing the ink jet head driving device 110 to drive the ink jet head module 104 to have a relative movement to a location over the ink receiver, making the liquid level of the ink 1184 in the nozzle 1182 changed so as to jet a predetermined amount of ink droplets to the ink receiver 106 out of the ink jet head 118 within each predetermined time interval during/within a given predetermined time, in order to prevent the nozzles 1182 from experiencing clogs in the respective openings thereof due to adhesion of hardened/dried ink. The predetermined amount of droplets and the predetermined time interval may vary depending on the material (i.e., composition) of the ink 1184. In general, if the ink 1184 contains a solvent with a higher boiling point (i.e., likely having a relatively low viscosity at room temperature, as well), advantageously, the predetermined amount of droplets is less, and the predetermined time interval is longer. In an alternative scenario, if the ink 1184 contains a solvent with a boiling point that is fairly low (i.e., likely having a relatively high viscosity at room temperature, as well), usefully, the predetermined amount of droplets may be higher (i.e., relative to the above-situation employing a higher boiling-point solvent), and the predetermined time interval may be shorter. For example, if a boiling point B1 of the solvent, in the ink 1184, is in a range B1<100° C., the predetermined number of droplets per each nozzle 1182 is in an approximate range of 100˜5000 droplets, and the predetermined time interval T1 is roughly in a range of 20 seconds to 5 minutes. Preferably, the predetermined amount corresponding to each nozzle 1182 is in a range of 2000˜3000 droplets, and the predetermined time interval Ti is roughly in a range of 30 seconds to 2.5 minutes. In another example, if a boiling point B2 of the solvent in the ink 1184 is in a range B2>180° C., the predetermined amount corresponding to each nozzle 1182 is in an approximate range of 100˜5000 droplets, and the predetermined time interval T2 is roughly in a range of 1 minutes to 5 minutes. Preferably, the predetermined amount corresponding to each nozzle 1182 is in a range of 1000˜3000 droplets, and the predetermined time interval T2 is roughly in a range of 1 minute to 3 minutes. Generally, every 100,000 droplets of ink have a volume between 0.0001 cubic centimeters and 0.02 cubic centimeters.
According to this present embodiment, in Step 210 and Step 210′, the ink on/at the nozzle forming face can sufficiently retain moisture (i.e., any given droplet is not at the nozzle forming face long enough to dry out, even when the ink jet system is not in use to deposit ink on substrates) and thus prevent the opening of the nozzle from clogging. As such, the opportunity for adhesion of hardened ink, formed due to the drying of ink remaining within the nozzles over time, is reduced. In evidence, the ink jetting method 200 can be applied to different kinds of inks employing respective solvents with different boiling points, as long as the predetermined amount of droplets and predetermined time interval are selected properly.
Simply stated, the present ink jet method for forming patterned layers on substrates permits a predetermined number of substrates to have respective patterned layers formed thereon. The ink jet method, however, further prevents clogging of the ink jet system when not in use to coat/layer substrates. A further step is provided, after all the desired substrates have been patterned, that causes the ink jet head driving device to drive the ink jet head module to have a relative movement to move to a location over an ink receiver, jetting a predetermined amount of droplets of ink from the nozzles to the ink receiver within each predetermined time interval during/over the course of a predetermined amount of time. By jetting a number of droplets in a given period, each nozzle is able to remain unclogged (i.e., the ink in a nozzle does not have sufficient time to dry/harden prior to being jetted).
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It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is only illustrative, and changes may be made in detail. Especially changes in matters of shape, size, and arrangement of parts; within the principles of the invention and to the full extent indicated by the broad or general meaning of the terms in which the appended claims are expressed.
