Coating processes – Measuring – testing – or indicating
Reexamination Certificate
2002-07-30
2004-08-03
Crispino, Richard (Department: 1734)
Coating processes
Measuring, testing, or indicating
C118S677000, C118S681000, C118S684000, C118S704000, C222S056000, C239S095000
Reexamination Certificate
active
06770320
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and a method for applying a fluid which can be used in a production process of electronic components, household electrical appliances, etc. for discharging a constant amount of various kinds of liquid such as adhesives, solder paste, phosphors, grease, paint, hot melt, medicines, foods, etc.
2. Description of the Related Art
While a liquid discharge apparatus (dispenser) has been conventionally used in a variety of fields, a technique of highly accurately and stably controlling to discharge a minute amount of fluid material becomes required in accordance with the current need for electronic components to be made compact with a high recording density. In the field of, for example, a surface mounting technique (SMT) for electronic components, high-speed, high-density, high-quality and automatic mounting into a micro-size is required and, the contents of the requirement to the dispenser are summarized as follows:
(1) To obtain a highly accurate application amount while holding the application amount for each time minute;
(2) To shorten a discharge time, i.e., to discharge, shut and start the discharge at high speeds; and
(3) To meet highly viscous fluids in powders.
In order to discharge a liquid of a minute flow rate, dispensers of an air pulse system, a groove type, and the like have been practically used heretofore.
Among the dispensers of the aforementioned types, the dispenser of the air pulse system as indicated in
FIG. 8
has been widely employed. The dispenser of this system supplies a constant amount of the air supplied from a constant pressure source
20
into a cylindrical container
10
in pulses, thereby discharging a constant amount of a liquid
25
,corresponding to an amount of a pressure rise in the container
10
through a nozzle
12
.
The dispenser of the air pulse system is poorly responsive when discharging the fluid
25
. Meanwhile, a screw type dispenser, such as a viscous pump, has also been put in practical use. The dispenser of this type generally adopts a structure wherein an object to which the liquid or the like is to be applied by the dispenser, and the dispenser are made relatively movable in X, Y and Z directions, so that the liquid can be applied linearly by moving the object to be applied and the dispenser relatively in either the X or the Y direction while discharging the liquid from the dispenser.
In the above-described conventional application method, as is apparent from
FIGS. 9C and 9D
, a discharge control signal for letting the dispenser carry out a discharge operation is set to rise and fall with the same timing as a timing of a rising edge and a falling edge of a movement control signal for moving the dispenser and the object to be applied in the X or Y direction. It takes a predetermined amount of time before a constant amount of the fluid is discharged after the discharge control signal is supplied in the above dispenser, as is shown in FIG.
9
D. Similarly, it takes a predetermined period of time before the fluid discharge is actually stopped after a signal instructing stopping the discharge is supplied. Therefore, an application state of the fluid from the dispenser to the object to be applied becomes one such as is represented in FIG.
9
A. Specifically, the application starts at an application start part
30
with the time delay from the rise of the discharge control signal, having an application amount gradually increased, whereas the fluid is turned to a mass shaped at a discharge termination part
32
because of the application amount being amassed by the time difference between the signal and the actual discharge stop. In other words, as indicated by a dotted line in
FIG. 9A
, it is difficult for the conventional fluid application apparatus to form a fixed fluid application region and obtain a uniform application amount over an entire range of the fluid application region. The reason for this is that starting and stopping the discharge of the fluid having fluidity is subject to a time lag, while moving the object to be applied and the dispenser in the X or Y direction is a mechanical operation without a time lag. Although, for example, an operation timer can be set to delay the movement in the X or Y direction, to stop the discharge earlier, etc. for solving the above problem and obtaining a normal application state, it is difficult to match the fluid discharge with the mechanical operation particularly in the case of a fluid which is viscous, and consequently the application state still varies.
In the field of forming circuits which increasingly becomes highly accurate and superfine; and in the fields of manufacturing processes of forming electrodes and ribs of image tubes such as PDPs (plasma display panels), CRTs, etc., applying a sealing material of liquid crystal panels, and manufacturing optical discs or the like; the following requirements are made in relation to a fine application technique:
(1) To be able to quickly stop the application after continuous application and to immediately restart the continuous application a short time later. It is ideal to control a flow rate in the order of, for example, a 0.01 second; and
(2) To be able to meet fluids in powders, for example, without crushing and breaking the powder, clogging a channel, or the like trouble by mechanically shutting the channel.
SUMMARY OF THE INVENTION
An object of the present invention is therefore to provide an apparatus and a method for applying a fluid, while eliminating the above-described problems, whereby an application amount of the fluid to be applied can be kept stable even at a fluid discharge start part and a fluid discharge termination part.
In order to accomplish the above objective, the present invention has following constructions.
According to a first aspect of the present invention, a fluid application apparatus, which is provided with an application head including:
a cylindrical discharge member for carrying out a discharge operation for a fluid to be applied;
a storage member shaped like a recess for storing the discharge member via a first gap in a diametrical direction of the discharge member and a second gap in an axial direction of the discharge member, having a discharge passage extending along a center axis of the discharge member to be opened to the second gap for discharging the fluid supplied to the first gap and moved to the second gap to the outside;
a moving device having an electro-magnetostrictive element for controlling starting and stopping the discharge of the fluid through the discharge passage to the outside by moving the discharge member along the axial direction;
a rotating device for rotating the discharge member along a circumferential direction of the discharge member; and
a movement groove formed to at least either a circumferential face of the discharge member facing the first gap or a first opposite face opposite to the circumferential face of the storage member for moving the fluid present at the first gap to the second gap by the rotation of the discharge member by the rotating device, and
a control unit connected to the moving device and the rotating device for carrying out to the moving device an operational control of moving the discharge member in a discharge direction along the axial direction when the fluid is to be discharged through the discharge passage to the outside.
The control unit can also control the rotating device to rotate the discharge member when the fluid is to be discharged through the discharge passage to the outside.
The above control unit can further control the rotating device so as to stop the rotation of the discharge member, and at the same time, control the moving device so as to move the discharge member in a direction opposite to the discharge direction along the axial direction when the fluid discharge through the discharge passage is to be stopped.
The fluid application apparatus can be further provided with a supporting member for supporting an object to which the fluid is
Maruyama Teruo
Nishikawa Hidenobu
Ono Shuji
Sonoda Takashi
Yamauchi Hiroshi
Crispino Richard
Koch, III George R.
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Apparatus and method for applying fluid does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for applying fluid, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for applying fluid will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3351723