Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
1999-03-04
2001-06-19
Look, Edward K. (Department: 3746)
Pumps
Motor driven
Electric or magnetic motor
C417S413300
Reexamination Certificate
active
06247908
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a structure and manufacturing method for a micro-pump and micro-valve in medical fields and analytic fields wherein essentially required are liquid feed of a slight amount of a liquid with accuracy and miniaturization of the apparatus itself.
There is one described, for example, in JP-A-5-164052 as a micro-pump being applied in the analytic field and the like. This invention is structured, within a casing
26
as shown in
FIG. 2
, by a fixed stacked-type piezoelectric actuator bonded at its end face with a liquid suction and discharge member
21
, and two stacked-type piezoelectric actuators
22
bonded at their end faces with valves
23
, so that a structure is provided that liquid feed is realized through a passage pipe port
24
and a pump chamber
25
by driving the three actuators.
Also, in the case of a micro-pump described in JP-A-5-1669, it is characterized as shown in
FIG. 3
in that a metal or polysilicon thin film
32
is formed on a sacrificial layer of an oxide film over a silicon substrate
31
, further a metal or polysilicon check valve is structured by removing the sacrificial layer through etching, and a pump is structured by a piezoelectric element
34
provided on a glass substrate
33
.
Meanwhile, in the case of a device described in JP-A-5-263763, a structure is made as shown in
FIG. 4
by attaching two pump-driving bimorph type piezoelectric elements
42
on and under a pump chamber
41
, and mounting flow control valves
45
formed by a valve body
43
and a bimorph type piezoelectric element
44
to a suction port and a discharge port, so that the pump-driving piezoelectric elements
42
and the fluid control valve piezoelectric elements
44
can be drive-controlled by a same controller
46
.
In a case where an active valve is manufactured by using a stacked-type piezoelectric element as shown in
FIG. 2
as its actuator, there has been a problem that the reduction in thickness was impossible due to the thickness of the stacked type piezoelectric element itself.
Also, in the micro-pump having the two check valves as shown in
FIG. 3
, there has been a problem that liquid feed is possible in only one direction due to its liquid feed realized by using the passive check valves.
Further, where using as shown in
FIG. 4
the valve by directly closing the passage with the piezoelectric element bimorph type actuators, there has possessed a problem that the actuators had to be protected because fluid contacts with the actuator.
Therefore it is an object in the present invention to realize a micro-pump which is realized high in tightness, capable of being made thin and high in pressure resistance and discharge efficiency, by using a unimorph actuator to obtain sufficient displacement in a diaphragm of a substrate portion and using such a structure as clamping a packing such as silicone rubber between the substrate portion and the ceiling plate portion.
Furthermore, it is another object in the present invention to realize a micro-pump which is realized high in tightness, capable of being made thin and feeding liquid bi-directional, and high in pressure resistance and discharge efficiency, by using a unimorph actuator to obtain sufficient displacement in a diaphragm of a substrate portion and using an integral structure with a substrate portion or ceiling plate portion and a packing.
SUMMARY OF THE INVENTION
In the present invention, high tightness is realized in the valve portion by employing such a structure as clamping a packing such as silicone rubber between a diaphragm on a substrate and a ceiling plate. Furthermore, a unimorph actuator is structured having a piezoelectric element attached to the diaphragm to realize such a structure of allowing fluid to flow between the packing and the diaphragm or between the packing and the ceiling plate, realizing active micro-valves.
Also, these two micro-valves and a pumping portion with the piezoelectric element and the diaphragm are connected by a passage to drive each actuator to effect liquid feed. Thus, a micro-pump is realized that is in a thin-type and high in pressure resistance and discharge efficiency, and capable of bi-directional liquid feed.
Furthermore, in the present invention, an integral structure with the substrate and the packing is realized by forming the packing in the diaphragm on the substrate, realizing high tightness with the ceiling plate bonded. Or otherwise, an integral structure with the ceiling plate and the packing is realized by forming the packing on the ceiling plate, realizing high tightness with the diaphragm on the bonded substrate. Further, a unimorph actuator is structured that is attached with the piezoelectric element for the diaphragm, realizing an active micro-valve. Also, in the similar manner a pumping portion is realized that acts to discharge liquid by the unimorph actuator having the piezoelectric element attached to the diaphragm.
Also, these micro-valves and the pumping portions are connected through passages so that valve opening and closing and liquid discharge are effected by driving each actuator, thereby realizing a micro-pump that is a thin type, high in pressure resistance and discharge efficiency and capable of bi-directional liquid feed.
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Patent Abstracts of Japan, vol. 009, No. 098 (M-375), Apr. 27, 1985.
Furuta Kazuyoshi
Shinohara Jun
Adams & Wilks
Gray Michael K.
Look Edward K.
Seiko Instruments Inc.
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