Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2003-03-06
2004-08-24
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S009000, C347S010000, C347S011000
Reexamination Certificate
active
06779863
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to head driving devices and methods, droplet ejecting apparatuses, head driving programs, device manufacturing methods, and devices. More particularly, the present invention relates to a head driving device and method for driving a head that ejects a highly viscous body, such as a liquid resin having high viscosity, a droplet ejecting apparatus including the head driving device, a head driving program, a device manufacturing method including, as one step, a step of ejecting a viscous body using the above-described method and manufacturing a liquid crystal display, an organic EL (Electroluminescence) display, a color filter substrate, a microlens array, an optical device having a coating layer, and other devices, and a device thereof.
2. Description of Related Art
Recently, various electronic devices, such as computers and handheld information devices, have been advancing greatly. In accordance with the advancement of the electronic devices, electronic devices having liquid crystal displays, and particularly color liquid crystal displays showing high display performance, have been increasing in number. Despite their size, color liquid crystal displays are capable of having a high display performance, and therefore applications for such devices have been expanding. A color liquid crystal display has a color filter substrate for colorizing an image to be displayed. Various methods for manufacturing the color filter substrate have been proposed. One such method proposed is a droplet ejecting method for causing R (red), G (green), and B (blue) droplets to land on the substrate in a predetermined pattern.
A droplet ejecting apparatus implementing the droplet ejecting method has a plurality of droplet ejecting heads that eject droplets. The droplet ejecting heads each have a fluid chamber for temporarily accumulating an external droplet, a piezoelectric element serving as a drive source that pressurizes a fluid in the fluid chamber to eject a predetermined amount of the fluid, and a nozzle face having a nozzle drilled therein, from which the droplet from the fluid chamber is ejected. These droplet ejecting heads are disposed at equal pitches and thus make a head group. While the head group scans the substrate along a scanning direction (for example, X direction), the droplets are ejected. As a result, the R, G, and B droplets land on the substrate. In contrast, the positional adjustment on the substrate in the direction orthogonal to the scanning direction (for example, Y direction) is made possible by moving a platform on which the substrate is placed.
SUMMARY OF THE INVENTION
The manufacture of the color filter substrate included in the above-described color liquid crystal display more often uses a highly viscous body having a higher viscosity than that of ink for use in color printers used at home. Since a less viscous body (for example, a viscous body having a viscosity of approximately 3.0 [mPa·s (milli·Pascal·second)] at room temperature (25° C.)) has a low viscosity resistance, the color printer used at home can eject a necessary amount of droplet even when a driving period of a piezoelectric element is short (for example, a few microseconds). Because the color printer used at home is required to achieve high-speed printing, a head driving device that drives a droplet ejecting head is designed to vibrate the piezoelectric element at high speed in order to achieve high-speed printing.
For example, a known head driving device includes a drive signal generator for receiving data that indicates the amount of change in voltage value of a drive signal applied to the piezoelectric element per reference clock and a clock signal that defines a period during which the voltage value of the drive signal is changed and for generating the drive signal on the basis of the data and the clock signal in synchronization with the reference clock. The reference clock input to the drive signal generator has a frequency of approximately 10 MHz. The data is a signed digital signal having approximately 10 bits. Until the above-described clock signal is input to the drive signal generator, the drive signal generator adds the value of the input data every time the reference clock is input, thereby generating a rising or falling waveform of the drive signal.
In the known head driving device, a drive signal having a steeply rising or falling waveform is generated by greatly increasing or decreasing the value of the data input to the drive signal generator. For example, when the data having the maximum value or minimum value (negative value) is input to the drive signal generator, a drive signal that suddenly rises or falls over the time of one cycle of the reference clock is generated. As a matter of fact, since a D/A converter disposed between the drive signal generator and the piezoelectric element has a response delay, the period during which the drive signal rises or falls is longer than the time of one cycle of the reference clock.
In contrast, a drive signal having a gradually rising or falling waveform is generated by decreasing the value of the data input to the drive signal generator and by inputting the clock signal at a later time. In order to simplify the description, it is assumed that the data is an unsigned 10-bit digital signal. In this case, there are 2
10
=1024 possible combinations for the value of the drive signal. When the data having the minimum value is input in order to generate a gradually rising waveform, the voltage value of the drive signal changes from the minimum value to the maximum value over a period of 1024 clocks of the reference clock. When the reference clock is at 10 MHz, the time of one cycle is 0.1 &mgr;s. Theoretically speaking, the period during which the drive signal rises or falls is variable within the range from approximately 0.1 to 102.4 &mgr;s.
As described above, a highly viscous body is used in the droplet ejecting apparatus for use in manufacturing a color filter substrate. It is thus necessary to vibrate the piezoelectric element for a long period of time in order to eject a necessary amount of droplet. For example, the manufacture of a color filter involves vibrating the piezoelectric element for a few milliseconds. The manufacture of a microlens involves vibrating the piezoelectric element for a long period of time of approximately one second. As described above, the known head driving device is designed to vibrate the piezoelectric element at high speed, and the maximum time during which the drive signal rises or falls is approximately 102.4 &mgr;s. There is a problem in that the head driving device used at home cannot be simply used as the head driving device of the droplet ejecting apparatus for ejecting a highly viscous body.
This problem does not only arises in the manufacture of a color filter substrate of a liquid crystal display, but also arises in the manufacture of an organic EL (Electroluminescence) display, the manufacture of a microlens array using a highly viscous transparent liquid resin, the formation of a coating layer on the surface of an optical element such as a spectacle lens using a highly viscous liquid resin, or the like. In short, the problem is a general problem with a device manufacturing method having, as one manufacturing step, a step of ejecting a viscous body.
In view of the foregoing circumstances, it is an object of the present invention to provide a head driving device and method for ejecting a necessary amount of a viscous body from a head having a pressure generating element, such as a piezoelectric element, a droplet ejecting apparatus including the head driving device, a head driving program, a device manufacturing method including, as one manufacturing step, a step of ejecting a viscous body using the above-described method, and a device manufactured using the droplet ejecting apparatus or the device manufacturing method.
In order to solve the foregoing problems, a head driving device of the present invention is a hea
Dudding Alfred
Meier Stephen D.
Oliff & Berridg,e PLC
Seiko Epson Corporation
LandOfFree
System and methods for providing a head driving device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System and methods for providing a head driving device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and methods for providing a head driving device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3314816