U.S. patent application number 15/338609 was filed with the patent office on 2017-02-16 for fluid jet device, drive device of fluid jet device, surgical instrument, and method of driving fluid jet device.
This patent application is currently assigned to SEIKO EPSON CORPORATION. The applicant listed for this patent is SEIKO EPSON CORPORATION. Invention is credited to Shinichi MIYAZAKI, Takeshi SETO, Kunio TABATA.
Application Number | 20170042563 15/338609 |
Document ID | / |
Family ID | 42007878 |
Filed Date | 2017-02-16 |
United States Patent
Application |
20170042563 |
Kind Code |
A1 |
SETO; Takeshi ; et
al. |
February 16, 2017 |
FLUID JET DEVICE, DRIVE DEVICE OF FLUID JET DEVICE, SURGICAL
INSTRUMENT, AND METHOD OF DRIVING FLUID JET DEVICE
Abstract
A fluid jet device including a fluid chamber with variable
capacity and a capacity varying section adapted to vary the
capacity of the fluid chamber in response to supply of a drive
signal. A drive waveform section making the capacity varying
section operate so as to compress the capacity of the fluid chamber
and a restoring drive waveform section making the capacity varying
section operate to restore the capacity of the fluid chamber before
compressing the capacity in a signal waveform. The drive signal
supply section controls supply content of the drive signal to
provide a restoring period adapted to restore a steady state of the
fluid flowing toward an inside of the fluid chamber in a period
from when the compressing drive waveform section in the drive
signal is supplied to when a subsequent compressing drive waveform
section is supplied.
Inventors: |
SETO; Takeshi; (Chofu-shi,
JP) ; MIYAZAKI; Shinichi; (Suwa-shi, JP) ;
TABATA; Kunio; (Shiojiri-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEIKO EPSON CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
SEIKO EPSON CORPORATION
Tokyo
JP
|
Family ID: |
42007878 |
Appl. No.: |
15/338609 |
Filed: |
October 31, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13928942 |
Jun 27, 2013 |
9510851 |
|
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15338609 |
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|
12552768 |
Sep 2, 2009 |
8506584 |
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13928942 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y10T 137/85986 20150401;
A61B 17/32037 20130101; A61B 17/3203 20130101; A61B 2017/00017
20130101 |
International
Class: |
A61B 17/3203 20060101
A61B017/3203 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 16, 2008 |
JP |
2008-236106 |
Claims
1. (canceled)
2. A surgical instrument comprising: a fluid chamber with a
variable capacity; a capacity varying section configured to vary
the capacity of the fluid chamber in response to the supply of a
drive signal; a nozzle configured to eject fluid supplied from the
fluid chamber; and a drive signal supply section configured to
supply the capacity varying section with the drive signal, the
driving signal including a compressing drive waveform section,
causing the capacity varying section to compress the capacity of
the fluid chamber, and a restoring drive waveform section, causing
the capacity varying section to restore the capacity of the fluid
chamber before compressing the capacity in a signal waveform of one
cycle, wherein the drive signal supplied by the drive signal supply
section to the capacity varying section also includes a constant
waveform section between the compressing drive waveform section and
the restoring drive waveform section, the constant waveform section
forming a constant signal level.
3. The surgical instrument according to claim 2, wherein the drive
signal supplied by the drive signal supply section to the capacity
varying section has the signal waveform of one cycle configured by
combining a part of a sine wave that forms the compressing drive
waveform section and whose one-cycle time length is T1, and a part
of a sine wave that forms the restoring drive waveform section and
whose one-cycle time length is T2, where T1<T2.
4. The surgical instrument according to claim 3, wherein the time
length of T2 is equal to or more than five times of the time length
of T1.
5. The surgical instrument according to claim 4, wherein the signal
level of the constant waveform section is equal to the maximum
level of a signal level of the compressing drive waveform
section.
6. The surgical instrument according to claim 2, wherein the signal
level of the constant waveform section is equal to the maximum
level of a signal level of the compressing drive waveform
section.
7. The surgical instrument according to claim 5, wherein the signal
level of the constant waveform section is equal to the maximum
level of the signal level of the restoring drive waveform
section.
8. The surgical instrument according to claim 6, wherein the signal
level of the constant waveform section is equal to the maximum
level of the signal level of the restoring drive waveform
section.
9. The surgical instrument according to claim 2, wherein the signal
waveform of the one cycle is in the shape of a trapezoidal
wave.
10. The surgical instrument according to claim 2, wherein the drive
signal supply section varies the time length of the constant
waveform section in response to the variation of a fluid jet
emission intensity
11. The surgical instrument according to claim 2, wherein the
capacity varying section includes: a diaphragm configured to seal
an end of the fluid chamber, and a piezoelectric element connected
to the diaphragm, wherein the piezoelectric element performs one of
expanding and shrinking in a direction perpendicular to a seal
surface in response to the supply of the drive signal, and wherein
the drive signal supply section causes the expansion of the
piezoelectric element to deform the diaphragm toward an inside of
the fluid chamber by supplying the compressing drive waveform
section in the drive signal, and causes the shrinking of the
piezoelectric element to restore the diaphragm in a deformed state
to the diaphragm in a state prior to the deformation in the
deformed state by supplying the restoring drive waveform section in
the drive signal.
Description
[0001] This is a Continuation of application Ser. No. 13/928,942
filed Jun. 27, 2013, which is a Continuation of application Ser.
No. 12/552,768 filed Sep. 2, 2009, which claims the benefit of
Japanese Application No. 2008-236106 filed Sep. 16, 2008. The
disclosures of these prior three applications are hereby
incorporated by reference herein in their entirety.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to a fluid jet device for
emitting a jet of a fluid at high speed, and in particular to a
fluid jet device suitable for emitting a jet of a fluid in the
condition of maintaining desired jet force.
[0004] 2. Related Art
[0005] In the past, as a fluid jet device for incising or excising
body tissue, there is known a device provided with a pulsation
generation section having a fluid chamber with a variable capacity,
an entrance channel and exit channel communicated to the fluid
chamber, and a capacity varying section for varying the capacity of
the fluid camber in response to supply of a drive signal, a
connection channel having one end communicated to the exit channel
and the other end provided with a fluid jet opening section (a
nozzle) with a diameter smaller than that of the exit channel, a
connection channel tube provided with the connection channel
penetrating therethrough and having rigidity with which the
pulsation of the fluid flowing from the fluid chamber can be
transmitted to the fluid jet opening section, and a pressure
generation section for supplying the entrance channel with the
fluid, and for supplying the entrance channel with the fluid with
the pressure generation section at a constant pressure, and at the
same time varying the capacity of the fluid chamber with the
capacity varying section to generate the pulsation, thereby
performing ejection operation of the fluid (e.g., JP-A-2008-82202
(Document 1)).
[0006] According to the Document 1, a patent application by the
inventors of the invention, in the case in which the capacity of
the fluid chamber of a fluid jet device is not varied, the fluid
flows through the fluid chamber in the condition in which the
supply pressure by the pressure generation section (e.g., a pump)
and the channel resistance balanced with each other. When shrinking
the fluid chamber rapidly, the pressure in the fluid chamber rises.
At that moment, since an increased amount of fluid ejected from the
exit channel is larger than a decreased amount of flow volume of
the fluid flowing from the entrance channel into the fluid chamber,
a pulsation flow occurs in the connection channel. The pressure
pulsation in the ejection operation propagates in the connection
channel tube, and thus the fluid jet is emitted from the fluid jet
opening section of the nozzle at the tip of the connection channel
tube. The fluid chamber becomes in a vacuum state (0 atm or nearly
0 atm) immediately after the pressure rise due to the interaction
between decrease in inflow volume of the fluid from the entrance
channel and increase in outflow of the fluid from the exit channel.
As a result, after predetermined time has elapsed due to both of
the pressure of the pump and the vacuum state inside the fluid
chamber, there is restored the flow of the fluid in the entrance
channel towards the inside of the fluid chamber at the same speed
as before the operation of the piezoelectric element.
[0007] In the technology of the related art described in the
Document 1, although it is arranged that the capacity varying
section configured including the piezoelectric element and a
diaphragm is driven by a pulsed drive signal, in the case, for
example, in which it is driven by a simple sinusoidal drive signal,
the subsequent capacity reduction operation (compressing operation)
might be performed before the flow proceeding toward the inside of
the fluid chamber is restored to the steady state. If the
subsequent compressing operation is performed before restoring the
steady state, it is not achievable to obtain sufficiently strong
jet force (jet).
SUMMARY
[0008] An advantage of some aspects of the invention is to provide
a fluid jet device, a drive device for the fluid jet device, a
surgical instrument, and a driving method of the fluid jet device,
each suitable for continuously emitting jet of the pulsation flow
in the condition of maintaining desired jet force.
[0009] A first aspect of the invention is directed to a fluid jet
device including a fluid chamber with a variable capacity, an
entrance channel communicated with the fluid chamber, an exit
channel communicated with the fluid chamber, a capacity varying
section adapted to vary the capacity of the fluid chamber in
response to supply of a drive signal, an opening section
communicated with a different end of the exit channel from an end
of the exit channel with which the exit channel is communicated
with the fluid chamber, a pressure generation section adapted to
supply the entrance channel with a fluid, and a drive signal supply
section adapted to supply the capacity varying section with a drive
signal including a compressing drive waveform section making the
capacity varying section operate so as to compress the capacity of
the fluid chamber and a restoring drive waveform section making the
capacity varying section operate so as to restore the capacity of
the fluid chamber before compressing the capacity in a signal
waveform of one cycle, and the drive signal supply section controls
supply content of the drive signal so as to provide a restoring
period adapted to restore a steady state of the fluid flowing
toward an inside of the fluid chamber in a period from when the
compressing drive waveform section in the drive signal is supplied
to the capacity varying section to when a subsequent one of the
compressing drive waveform section is supplied to the capacity
varying section.
[0010] According to the configuration described above, when the
drive signal supply section supplies the capacity varying section
with the compressing drive waveform section in the drive signal,
the capacity varying section acts to compress the capacity of the
fluid chamber, and thus the inside of the fluid chamber is
compressed. Then, when the supply of the compressing drive waveform
section is terminated, the restoring drive waveform section in the
drive signal is then supplied to the capacity varying section.
Thus, the capacity varying section acts in the direction of
restoring the capacity of the fluid chamber to the state prior to
the compression, thereby restoring the inside of the fluid chamber,
which is now in the compressed state. Further, the drive signal
supply section controls the supply content of the drive signal so
that the restoring period for restoring the flow of the fluid
toward the fluid chamber to be in the steady state is provided in a
period from the end of supply of the compressing drive waveform
section to the supply of the subsequent compressing drive waveform
section.
[0011] In other words, when the drive signal supply section
terminates the supply of the previous compressing drive waveform
section to the capacity varying section, it is possible to restore
the steady state (the state in which the fluid is flowing while the
supply pressure from the pressure generation section and the flow
resistance are balanced with each other) in the fluid chamber prior
to the supply of the subsequent compressing drive waveform
section.
[0012] Thus, since it becomes possible to make the capacity varying
section perform the subsequent compressing operation after the flow
of the fluid toward the fluid chamber is restored to be the steady
state, it is possible to obtain an advantage that emission of the
fluid jet can continuously be performed while keeping the jet force
in a constant and strong state.
[0013] Here, the expression "to be communicated with" means that
one thing and the other thing are connected to each other, no
matter whether directly or indirectly, so that a fluid can flow
therethrough. For example, the condition in which an end of the
exit channel and the fluid jet opening section are connected to
each other directly or via a channel tube or the like so that the
fluid can flow therethrough corresponds to the expression.
[0014] Further, a second aspect of the invention is directed to the
fluid jet device of the first aspect of the invention, wherein a
time length of the compressing drive waveform section is denoted as
T.sub.red, a time length of the restoring drive waveform section is
denoted as T.sub.exp, average pressure in the fluid chamber in a
supply period of the compressing drive waveform section is denoted
as P.sub.gen, pressure applied to the entrance channel in the fluid
chamber on a pressure generation section side in a supply period of
the restoring drive waveform section is denoted as P.sub.sup, and
the drive signal supply section supplies the capacity varying
section with the drive signal configured including the compressing
drive waveform section with the time length T.sub.red and the
restoring drive waveform section with the time length T.sub.exp
satisfying a relationship of a following formula.
T.sub.red.times.(P.sub.gen-P.sub.sup).ltoreq.T.sub.exp.times.P.sub.sup
[0015] Here, denoting the cross section of the entrance channel as
s, the momentum M.sub.g acting on the entrance channel on the fluid
chamber side is expressed as
M.sub.g=s.times.T.sub.red.times.(P.sub.gen-P.sub.sup), and the
momentum M.sub.s acting on the entrance channel on the pressure
generation section side is expressed as
M.sub.s=s.times.T.sub.exp.times.P.sub.sup. Further, in general,
P.sub.sup takes a far smaller value compared to P.sub.gen
(P.sub.gen>>P.sub.sup).
[0016] Further, in a period (the period of T.sub.exp) during which
the capacity of the fluid chamber is expanding (restoring the
original capacity), the average pressure of the fluid chamber
becomes 0 atm or nearly 0 atm because the fluid is drawn due to the
inertance of the exit channel. In other words, if the momentum
M.sub.s provided thereto in T.sub.exp is equal to or larger than
the momentum M.sub.g provided thereto in T.sub.red, the fluid can
be restored to the original steady state.
[0017] Therefore, in the case of the configuration described above,
since it is possible to supply the capacity varying section with
the drive signal having the compressing drive waveform section with
the time length T.sub.red and the restoring drive waveform section
with the time length T.sub.exp satisfying the relationship of the
formula described above, the fluid can be restored from the vacuum
state to the original steady state in one cycle period of the drive
signal.
[0018] Thus, since it becomes possible to make the capacity varying
section perform the subsequent compressing operation after the flow
of the fluid toward the fluid chamber is restored to be the steady
state, it is possible to obtain an advantage that emission of the
fluid jet can continuously be performed while keeping the jet force
in a strong state.
[0019] Further, it might be possible, for example, that a signal is
raised rapidly and then dropped rapidly as the burst waveform shown
in FIG. 16, and then, waiting for the flow toward the fluid chamber
to be restored before supplying the subsequent signal.
[0020] However, in this case, since the inside of the fluid chamber
expands (restores the original capacity) rapidly, the vacuum
bubbles in the fluid chamber also expand, and the gases solved in
the fluid become apt to be discharged toward the vacuum bubbles. As
a result, although the flow to the fluid chamber is restored and
the vacuum bubbles disappear, since the bubbles caused by the gases
once discharged from the liquid never disappear, the bubbles lower
the rigidity of the fluid chamber, and as a result, the rise in
pressure might be prevented to make the emission of the fluid jet
weaker.
[0021] According to the configuration described above, since the
drive signal satisfying the relationship of the formula described
above can be supplied to the capacity varying section,
P.sub.gen>>P.sub.sup is satisfied, and therefore, T.sub.exp
becomes a longer time length than T.sub.red, and as a result, the
capacity of the fluid chamber thus compressed is restored to the
original state relatively slowly, and as a result, the vacuum
bubbles become smaller, and it becomes possible to make it
difficult to discharge the gases from the fluid to the vacuum
bubbles.
[0022] Thus, the advantage that the rigidity of the fluid chamber
can be prevented from dropping due to the bubbles of the gases can
also be obtained.
[0023] Further, a third aspect of the invention is directed to the
fluid jet device of the first or the second aspect of the
invention, wherein the drive signal supply section controls the
supply content of the drive signal so as to provide the restoring
period in the supply period of the restoring drive waveform
section.
[0024] According to the configuration described above, in a period
of one cycle of the drive signal, it is possible to perform
compression of the capacity of the fluid chamber, restoring to the
original capacity, and restoring of the flow of the fluid toward
the fluid chamber to the steady state. Thus, since it becomes
possible to make the capacity varying section perform the
subsequent compressing operation after the flow of the fluid toward
the fluid chamber is restored to be the steady state, it is
possible to obtain an advantage that emission of the fluid jet can
continuously be performed while keeping the jet force in a strong
state.
[0025] Further, a fourth aspect of the invention is directed to the
fluid jet device of the third aspect of the invention, wherein the
drive signal supply section supplies the capacity varying section
with the drive signal having a constant waveform section holding a
constant signal level as the restoring period between the
compressing drive waveform section and the restoring drive waveform
section and in a part of the restoring drive waveform section.
[0026] According to the configuration described above, it is
possible to operate the capacity varying section so as to keep
(stop varying the capacity) the capacity of the fluid chamber
constant for a predetermined time period after compressing the
capacity of the fluid chamber as a restoring period.
[0027] Thus, since the vacuum bubbles can be made to disappear in
the state in which the capacity is compressed and the capacity is
not substantially varied, an advantage of making the vacuum bubbles
disappear in a short period of time can be obtained.
[0028] Further, since it is also possible to restore the capacity
after the vacuum bubbles disappear or roughly disappear, an
advantage that the discharge of the gases from the fluid can be
prevented can also be obtained.
[0029] Further, a fifth aspect of the invention is directed to
either one of the fluid jet device of the first through fourth
aspects of the invention, wherein a storage section adapted to
store waveform information of the drive signal is additionally
provided, the drive signal supply section generates the drive
signal based on the waveform information stored in the waveform
information storage section, and supplies the capacity varying
section with the drive signal.
[0030] According to the configuration described above, for example,
by storing the waveform data sampled at a predetermined cycle as
the waveform information, it is possible to easily generate the
drive signal of the target waveform from the waveform data.
[0031] Further, a sixth aspect of the invention is directed to the
fluid jet device of either one of the first through fifth aspects
of the invention, wherein the drive signal supply section supplies
the capacity varying section with the drive signal having the
signal waveform of one cycle configured by combining a part of a
sine wave, which forms the compressing drive waveform section, and
a time length of one cycle of which is T1, and a part of a sine
wave, which forms the restoring drive waveform section, and a time
length of one cycle of which is T2 (T1.noteq.T2).
[0032] According to the configuration described above, since it is
possible to configure the drive signal by combining a part of one
sine wave and a part of another sine wave, the time length of one
cycle of the one sine wave and the time length of one cycle of the
another sine wave being different from each other, denoting, for
example, the wavelength of the sine wave of T1 as .lamda.1, the
wavelength of the sine wave of T2 as .lamda.2, the drive signal can
be configured by combining a waveform portion corresponding to the
anterior half .lamda.1/2 of the sine wave of T1 and a waveform
portion corresponding to the posterior half .lamda.2/2 of the sine
wave of T2.
[0033] Thus, there is obtained an advantage that the drive signal,
which has the time length of the posterior half cycle longer then
the time length of the anterior half cycle, and at the same time,
which has the signal waveform of one cycle different from a simple
sine wave, can easily be configured. In other words, the drive
signal including the restoring period in the restoring drive
waveform section can easily be configured.
[0034] Further, a seventh aspect of the invention is directed to
the fluid jet device of the fifth aspect of the invention, wherein
a shape of a trapezoidal wave is adopted as the signal waveform of
one cycle.
[0035] According to the configuration described above, since the
drive signal (analog signal) can be generated from the waveform
data of a smaller number of samples compared to the case with the
sine wave signals, the data capacity of the waveform data stored in
the waveform information storage section can be reduced.
[0036] Thus, there can be obtained an advantage that the storage
capacity of the waveform information storage section can be made
smaller compared to the case of using the sine wave signal as the
drive signal, and at the same time, there can also be obtained an
advantage that a larger number of types of waveform data can be
stored in the waveform information storage section with the same
capacity compared to the case in which the sine wave signal is used
as the drive signal.
[0037] Further, an eighth aspect of the invention is directed to
the fluid jet device of the seventh aspect of the invention,
wherein the storage section stores nodal point information of the
trapezoidal wave as the waveform information, and the drive signal
supply section generates the drive signal of the trapezoidal wave
based on the nodal point information stored in the storage
section.
[0038] According to the configuration described above, by storing
only the nodal point information of each of the trapezoidal waves
as the waveform information it is possible to generate the desired
drive signal from the waveform information, and therefore, it is
possible to reduce the waveform information to be stored in the
storage section to a smaller amount of data.
[0039] Further, in the case in which real-time access is required
to generate the drive signal, it is enough to read out a smaller
amount of data compared to the case of using the sine wave signal
as the drive signal, and therefore, such a high-speed access
mechanism required for the case of using the sine wave signal as
the drive signal is not required.
[0040] Therefore, there can be obtained an advantage that the drive
control using the waveform information with various wavelengths and
amplitudes can be realized at lower cost compared to the case of
using the sine wave signal as the drive signal.
[0041] Further, a ninth aspect of the invention is directed to the
fluid jet device of either one of the first through eighth aspects
of the invention, wherein a diameter of an end of the exit channel
on a fluid chamber side is set to be larger than a diameter of an
end of the exit channel on an opening section side.
[0042] According to the configuration described above, there can be
obtained an advantage that the fluid flowing from the fluid chamber
side end of the exit channel can be emitted in the opening section
side end of the exit channel as a pulsed droplet with higher
pressure and higher speed.
[0043] Further, a tenth aspect of the invention is directed to the
fluid jet device of either one of the first through ninth aspects
of the invention, wherein an inertance of the entrance channel is
set to be larger than an inertance of the exit channel.
[0044] According to the configuration described above, when driving
the capacity varying section to compress the capacity of the fluid
chamber, a larger pulsation flow than the inflow amount of the
fluid from the entrance channel to the fluid chamber occurs in the
exit channel, thus the pulsed fluid ejection can be performed in
the connection channel tube.
[0045] Further, an eleventh aspect of the invention is directed to
the fluid jet device of either one of the first through ninth
aspects of the invention, wherein a combined inertance on an
upstream side of the fluid chamber including the entrance channel
is larger than an inertance on a downstream side of the fluid
chamber including the exit channel.
[0046] According to the configuration described above, when driving
the capacity varying section to compress the capacity of the fluid
chamber, a larger pulsation flow than the inflow amount of the
fluid from the entrance channel to the fluid chamber occurs in the
exit channel, thus the pulsed fluid ejection can be performed in
the connection channel tube.
[0047] Further, a twelfth aspect of the invention is directed to
the fluid jet device of either one of the first through eleventh
aspects of the invention, wherein there are further provided a
connection channel having a first end communicated with the exit
channel, and a second end provided with the opening section having
a diameter smaller than a diameter of the exit channel, and a
connection channel tube through which the connection channel
penetrates, and which transmits pulsation of the fluid flowing from
the fluid chamber to the opening section.
[0048] According to the configuration described above, it becomes
possible to more strongly emit a jet of the fluid, and at the same
time, in the case in which the fluid jet device according to this
aspect of the invention is used, for example, as a surgical
instrument, it becomes applicable to various operations such as an
operation on the brain in which the affected area is located in a
recess.
[0049] Further, a thirteenth aspect of the invention is directed to
the fluid jet device of either one of the first through twelfth
aspects of the invention, wherein the capacity varying section is
configured including a diaphragm adapted to seal an end of the
fluid chamber, and a piezoelectric element having one end fixed to
the diaphragm and one of expanding and shrinking in a direction
perpendicular to a seal surface in response to supply of the drive
signal, and the drive signal supply section makes the piezoelectric
element expand to deform the diaphragm toward an inside of the
fluid chamber by supplying the compressing drive waveform section
in the drive signal, and makes the piezoelectric element shrink to
restore the diaphragm in a deformed state to the diaphragm in a
state prior to the deformation by supplying the restoring drive
waveform section in the drive signal.
[0050] According to the configuration described above, since the
piezoelectric element is adopted as the capacity varying section,
there can be obtained an advantage that the capacity variation of
the fluid chamber can easily be controlled by the drive signal, and
at the same time, there can also be obtained an advantage that the
simplification of the structure and associated downsizing can be
realized. Further, since it is possible to set the highest
frequency of the capacity variation of the fluid chamber to be a
high frequency equal to or higher than, for example, 1 kHz, there
can be obtained an advantage that the emission of a jet of the
pulsation flow can be executed at high speed and with a short cycle
period.
[0051] Meanwhile, a fourteenth aspect of the invention is directed
to a drive device of a fluid jet device including a fluid chamber
with a variable capacity, an entrance channel and an exit channel
each communicated with the fluid channel, a capacity varying
section adapted to vary a capacity of the fluid chamber in response
to supply of a drive signal, an opening section communicated with a
different end of the exit channel from an end of the exit channel
communicated with the fluid chamber, a pressure generation section
adapted to supply the entrance channel with a fluid, and a drive
signal supply section adapted to supply the capacity varying
section with a drive signal including a compressing drive waveform
section making the capacity varying section operate so as to
compress the capacity of the fluid chamber and a restoring drive
waveform section making the capacity varying section operate so as
to restore the capacity of the fluid chamber before compressing the
capacity in a signal waveform of one cycle, and the drive signal
supply section controls supply content of the drive signal so as to
provide a restoring period adapted to restore a steady state of the
fluid flowing toward an inside of the fluid chamber in a period
from when the compressing drive waveform section in the drive
signal is supplied to the capacity varying section to when a
subsequent one of the compressing drive waveform section is
supplied to the capacity varying section.
[0052] According to the configuration described above,
substantially the same functions and advantages as of the fluid jet
device according to the first aspect of the invention can be
obtained.
[0053] Further, a fifteenth aspect of the invention is directed to
a surgical instrument adapted to assist a therapeutic treatment of
an affected area by fluid jet emission, including the fluid jet
device according to either one of the first through thirteenth
aspects of the invention.
[0054] According to the configuration described above, it is
possible to perform assistance of a therapeutic treatment such as
excision of an affected area such as a tumor using a fluid jet
emission by the fluid jet device according to either one of the
first through thirteenth aspects of the invention.
[0055] Further, a sixteenth aspect of the invention is directed to
a method of driving a fluid jet device including the steps of (a)
providing a fluid chamber with a variable capacity, an entrance
channel and an exit channel each communicated with the fluid
chamber, a capacity varying section adapted to vary a capacity of
the fluid chamber in response to supply of a drive signal, an
opening section communicated with a different end of the exit
channel from an end of the exit channel communicated with the fluid
chamber, a pressure generation section adapted to supply the
entrance channel with a fluid, and a drive signal supply section,
and (b) making the drive signal supply section supply the capacity
varying section with a drive signal including a compressing drive
waveform section making the capacity varying section operate so as
to compress the capacity of the fluid chamber and a restoring drive
waveform section making the capacity varying section operate so as
to restore the capacity of the fluid chamber before compressing the
capacity in a signal waveform of one cycle, and in step (b), the
drive signal supply section is made to control supply content of
the drive signal so as to provide a restoring period adapted to
restore a steady state of the fluid flowing toward an inside of the
fluid chamber in a period from when the compressing drive waveform
section in the drive signal is supplied to the capacity varying
section to when a subsequent one of the compressing drive waveform
section is supplied to the capacity varying section.
[0056] According to the configuration described above,
substantially the same functions and advantages as of the fluid jet
device according to the first aspect of the invention can be
obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
[0057] The invention will now be described with reference to the
accompanying drawings, wherein like numbers reference like
elements.
[0058] FIG. 1 is an explanatory diagram showing a schematic
configuration of a fluid jet device according to the present
embodiment of the invention.
[0059] FIG. 2 is a cross-sectional view showing a structure of a
pulsation generation section according to the embodiment of the
invention.
[0060] FIG. 3 is an exploded diagram of a fluid jet emitting
section.
[0061] FIG. 4 is a plan view showing a form of an entrance
channel.
[0062] FIG. 5 is a block diagram showing a detailed configuration
of a drive section.
[0063] FIG. 6 is a flowchart showing a process of generating a
signal waveform in the drive section.
[0064] FIG. 7 is a flowchart showing a process of supplying the
pulsation generation section with a drive signal in the drive
section.
[0065] FIG. 8 is a diagram showing an example of the signal
waveform generated by combining two types of sine waves.
[0066] FIG. 9A is a diagram showing an example of a method of
expanding a waveform, and FIG. 9B is a diagram showing an example
of a signal waveform of a drive signal according to a second
embodiment.
[0067] FIG. 10 is a block diagram showing a detailed configuration
of a drive signal supply section according to a third
embodiment.
[0068] FIG. 11 is a diagram showing an example of a trapezoidal
wave forming the drive signal.
[0069] FIG. 12 is a flowchart showing a process of outputting the
drive signal in a drive signal supply process of the third
embodiment.
[0070] FIG. 13 is a flowchart showing a counter condition setting
process corresponding to the steps S308 and S324.
[0071] FIG. 14 is a diagram showing an example of waveform
information of the third embodiment.
[0072] FIG. 15 is a diagram showing an output example of a drive
signal of a trapezoidal wave.
[0073] FIG. 16 is a diagram showing an example of a drive signal
having a burst wave for driving the piezoelectric element.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
First Embodiment
[0074] A first embodiment of the invention will hereinafter be
explained with reference to the accompanying drawings. FIGS. 1
through 8 are diagrams showing a fluid jet device, a drive device
of the fluid jet device, a surgical instrument, and a method of
driving the fluid jet device according to the first embodiment of
the invention.
[0075] It should be noted that the fluid jet device according to
the embodiment of the invention can be adopted for various purposes
such as drawing with ink or the like, cleaning a fine object and a
structure, ablation or excision of an object, and a surgical knife,
and in the embodiment explained hereinafter, the explanations are
presented exemplifying the fluid jet device suitable for incising
or excising body tissue. Therefore, the fluid used in the
embodiment is water, saline, medical solution, or the like.
[0076] Firstly, a configuration of the fluid jet device according
to the embodiment of the invention will be explained with reference
to FIG. 1. FIG. 1 is an explanatory diagram showing a schematic
configuration of the fluid jet device 1 according to the present
embodiment of the invention.
[0077] As shown in FIG. 1, the fluid jet device 1 is configured
including, as a basic configuration, a fluid jet emitting section 2
configured including a fluid container 10 for containing the fluid,
a pump 20 as a pressure generation section, and a pulsation
generation section 100 for making a pulsing flow of the fluid
supplied from the pump 20, and a drive section 30 for driving the
pulsation generation section 100.
[0078] A connection channel tube 200 with a thin pipe shape is
connected to the pulsation generation section 100, and a tip
portion of the connection channel tube 200 is provided with a
nozzle 211 with a shrunk channel inserted therein.
[0079] Then, the flow of the fluid in the fluid jet device 1 will
briefly be explained with reference to FIGS. 1 and 2.
[0080] Here, FIG. 2 is a cross-sectional view showing a structure
of the pulsation generation section 100 according to the embodiment
of the invention. It should be noted that the lateral direction in
FIG. 2 corresponds to the vertical direction. Further, FIG. 2 is a
cross-sectional diagram along the A-A' line shown in FIG. 3
described later.
[0081] The fluid contained in the fluid container 10 is suctioned
by the pump 20 via a connection tube 15, and supplied to the
pulsation generation section 100 at constant pressure via a
connection tube 25. The pulsation generation section 100 is
provided with a fluid chamber 501, and a capacity varying section
for varying the capacity of the fluid chamber 501 in accordance
with a drive signal from the drive section 30, and driving the
capacity varying section to generate pulsation, thereby emitting a
jet of fluid at high speed through a connection channel tube 200
and a nozzle 211. Detailed explanations of the pulsation generation
section 100 will be described later.
[0082] It should be noted that, when performing an operation using
the fluid jet device 1, the region the operator grips is the
pulsation generation section 100. Therefore, it is preferable that
the connection tube 25 to the pulsation generation section 100 is
as flexible as possible. In order for achieving the above, it is
preferable to apply the lowest possible pressure to the fluid in a
range in which the fluid can be sent to the pulsation generation
section 100 using a flexible tube with a thin wall.
[0083] Further, in particular in the case such as an operation on
the brain, in which a failure in the device might cause a
significant accident, it is necessary to prevent a high-pressure
fluid from spouting in response to break of the connection tube 25,
and in view of this point, it is required to keep the fluid at low
pressure.
[0084] Hereinafter, a structure of the pulsation generation section
100 will be explained with reference to FIGS. 2 through 4.
[0085] Here, FIG. 3 is an exploded view of the fluid jet emitting
section 2, and FIG. 4 is a plan view showing a form of an entrance
channel 503, and shows an appearance of an upper case 500 viewed
from a bonded surface side between the upper case 500 and a lower
case 301.
[0086] As shown in FIGS. 2 through 4, the pulsation generation
section 100 is provided with the upper case 500 with threaded holes
500a opened on the four corners thereof, and the lower case 301
with threaded holes 301a (not shown) opened on the four corners
thereof. Further, the upper case 500 and the lower case 301 are
bonded on the surfaces thereof opposed to each other so that the
threaded holes 500a and the threaded holes 301a are opposed
respectively to each other, and four screws 600 (not shown) are
screwed in the threaded holes 500a and 301a, thereby screwing the
upper case 500 and the lower case 301 to each other.
[0087] The lower case 301 is a hollow cylinder-shaped member having
a brim section, and one end thereof is sealed with a bottom plate
311. In the internal space of the lower case 301, there is disposed
a piezoelectric element 401 as one of the members forming the
capacity varying section.
[0088] The piezoelectric element 401 is a stacked piezoelectric
element, and forms an actuator. One end of the piezoelectric
element 401 is fixed to a diaphragm 400 via an upper plate 411, and
the other end thereof is fixed to an upper surface 312 of the
bottom plate 311.
[0089] Further, the diaphragm 400 is formed of a disc-like metal
thin plate, and has a peripheral portion adhering and fixed to a
bottom surface of a ring-like concave section 303 provided to the
upper surface side of the lower case 301 within the concave section
303. On the upper surface of the diaphragm 400, there is disposed,
in a stacked manner, a reinforcing plate 410 formed of a disk-like
metal thin plate having a circular opening section at the center
thereof.
[0090] According to this configuration, by the drive section 30
inputting a drive signal to the piezoelectric element 401, the
piezoelectric element 401 expands or shrinks, and the upward force
caused by the expansion and the downward force caused by the
shrinkage move the upper plate 411 in up-and-down directions. Then,
the movement of the upper plate 411 deforms the diaphragm 400,
thereby varying the capacity of the fluid chamber 501.
[0091] In other words, the capacity varying section is composed of
the piezoelectric element 401, the upper plate 411, the diaphragm
400, and the reinforcing plate 410.
[0092] The upper case 500 has a circular concave section formed at
the central section of the surface thereof opposed to the lower
case 301, and a solid of revolution composed of the concave section
and the diaphragm 400 and filled with a fluid is defined as the
fluid chamber 501. In other words, the fluid chamber 501 is defined
as a space surrounded by a seal surface 505 of the concave section
of the upper case 500, inner circumferential wall 501a, and the
diaphragm 400. At a substantially central section of the fluid
chamber 501, there is bored an exit channel 511.
[0093] The exit channel 511 penetrates from the fluid chamber 501
to an end of an exit channel tube 510 disposed so as to protrude
from one end surface of the upper case 500. A connection section of
the exit channel 511 with the seal surface 505 of the fluid chamber
501 is smoothly rounded in order for reducing the fluid
resistance.
[0094] It should be noted that although the shape of the fluid
chamber 501 described hereinabove is a substantially cylindrical
shape sealed at the both ends, this is not a limitation, but the
shape can be a conical shape, a trapezoidal shape, or a
hemispherical shape in the side view. For example, by adopting a
funnel-like shape as the connection section of the exit channel 511
with the seal surface 505, it becomes easier to discharge bubbles
in the fluid chamber 501 described later.
[0095] A connection channel tube 200 is connected to the exit
channel tube 510. The connection channel tube 200 is provided with
a connection channel 201 penetrating therethrough, and the diameter
of the connection channel 201 is larger than the diameter of the
exit channel 511. Further, the tube wall of the connection channel
tube 200 is formed to have a thickness in a range of providing
rigidity not absorbing the pressure pulsation of the fluid.
[0096] A nozzle 211 is inserted in the tip portion of the
connection channel tube 200. The nozzle 211 is provided with a
fluid jet opening section 212 penetrating therethrough. The
diameter of the fluid jet opening section 212 is smaller than the
diameter of the connection channel 201.
[0097] On a side surface of the upper case 500, there is disposed
an entrance channel tube 502 so as to protrude therefrom, the
entrance channel tube 502 being inserted into the connection tube
25 for supplying the fluid from the pump 20, and provided with an
entrance channel side connection channel 504 penetrating
therethrough. The connection channel 504 is communicated with the
entrance channel 503. The entrance channel 503 is formed on the
peripheral portion of the seal surface 505 of the fluid chamber 501
to have a groove shape, and is communicated with the fluid chamber
501.
[0098] On the bonded surface between the upper case 500 and the
lower case 301 at a position apart from the outer circumference of
the diaphragm 400, there are formed a gasket groove 304 on the
lower case 301 side and a gasket groove 506 on the upper case 500
side, and in the space formed by the gasket grooves 304, 506, there
is mounted a ring-like gasket 450.
[0099] Here, when assembling the upper case 500 and the lower case
301 together, a peripheral portion of the diaphragm 400 and a
peripheral portion of the reinforcing plate 410 have close contact
with each other by the peripheral portion of the seal surface 505
of the upper case 500 and the bottom surface of the concave section
303 of the lower case 301. On this occasion, the gasket 450 is
pressurized by the upper case 500 and the lower case 301 to prevent
leakage of the fluid from the fluid chamber 501.
[0100] The inside of the fluid chamber 501 becomes in a
high-pressure state of, for example, 30 atm (3 MPa) or higher when
ejecting the fluid, and although it is possible that the fluid
slightly leaks at each of the bonding sections between the
diaphragm 400, the reinforcing plate 410, the upper case 500, and
the lower case 301, the gasket 450 prevents the leakage.
[0101] When disposing the gasket 450 as shown in FIG. 2, the gasket
450 is compressed by the pressure of the fluid leaking from the
fluid chamber 501 at high pressure, and is further firmly pressed
against inside walls of the gasket grooves 304, 506, and therefore,
the leakage of the fluid can more reliably be prevented.
Accordingly, the high-rate of pressure rise in the fluid chamber
501 can be maintained when driving.
[0102] Subsequently, the entrance channel 503 provided to the upper
case 500 will be explained in greater detail.
[0103] As shown in FIG. 4, the entrance channel 503 is formed by a
groove provided to the peripheral portion of the seal surface 505
of the upper case 500 and the reinforcing plate 410 pressed against
and fixed to the seal surface 505.
[0104] The entrance channel 503 is communicated with the fluid
chamber 501 at one end thereof, and is communicated with the
connection channel 504 at the other end thereof. At a connection
section between the entrance channel 503 and the connection channel
504, there is formed a fluid reservoir 507. Further, a connection
section between the fluid reservoir 507 and the entrance channel
503 is smoothly rounded, thereby reducing the fluid resistance.
[0105] Further, the entrance channel 503 is communicated with the
fluid chamber 501 toward a substantially tangential direction with
respect to the inner circumferential sidewall 501a of the fluid
chamber 501. The fluid supplied from the pump 20 at constant
pressure flows along the inner circumferential sidewall 501a (in
the direction indicated by the arrow in the drawing) to generate a
swirling flow in the fluid chamber 501. Due to the centrifugal
force of the swirling flow, the bubbles with a low density
contained in the fluid chamber 501 are gathered at the central
portion of the swirling flow.
[0106] Then, the bubbles thus gathered at the central portion are
discharged from the exit channel 511. Therefore, it is more
preferable for the exit channel 511 to be disposed near the center
of the swirling flow, namely at the axially central portion of the
solid of revolution. In the example shown in FIG. 4, the entrance
channel 503 is curved to have a spiral planar shape. Although it is
possible for the entrance channel 503 to be communicated with the
fluid chamber 501 with a straight line, it is curved because it is
required to increase the channel length of the entrance channel 503
in order for obtaining a desired inertance in a small space.
[0107] It should be noted that as shown in FIG. 2, the reinforcing
plate 410 is disposed between the diaphragm 400 and the peripheral
portion of the seal surface 505 where the entrance channel 503 is
formed. The purpose for providing the reinforcing plate 410 is to
enhance durability of the diaphragm 400. Since a notch-like
connection opening section 509 is provided to the connection
section of the entrance channel 503 with the fluid chamber 501, it
is conceivable that stress concentration is caused in the vicinity
of the connection opening section 509 when the diaphragm 400 is
driven at a high frequency, thereby causing fatigue breakdown.
Therefore, it is arranged that the stress concentration can be
prevented from occurring in the diaphragm 400 by disposing the
reinforcing plate 410 having a continuous opening section without a
notch section.
[0108] Further, although in the fluid jet emitting section 2
explained hereinabove, it is arranged that the four threaded holes
500a are bored at outer peripheral portion of the upper case 500,
and the upper case 500 and the lower case 301 are screwed at the
threaded holes, the configuration of the fluid jet emitting section
2 is not limited thereto. For example, although omitted from the
drawing, it is possible to bond the reinforcing plate 410 and the
diaphragm 400 with each other, thereby stacking and fixing them
integrally to each other. As a fixing method, it is possible to
adopt sticking with an adhesive, solid-phase diffusion bonding,
welding, and so on, and it is further preferable that the
reinforcing plate 410 and the diaphragm 400 adhere to each other in
the bonded surface.
[0109] Further, although in the fluid jet emitting section 2
described hereinabove, there is adopted a configuration of
connecting the exit channel 511 and the nozzle 211 via the
connection channel tube 200, the configuration is not limited
thereto, and it is also possible to insert the nozzle 211 in an end
of the exit channel 511 on the opposite side to the fluid chamber
501 without using the connection channel tube 200. On this
occasion, a more simple configuration becomes possible.
[0110] Further, when used in an operation, it is more preferable to
adopt a configuration of using the connection channel tube 200 to
obtain a longer distance between a handpiece and a fluid jet
ejection port.
[0111] Then, fluid ejection of the pulsation generation section 100
according to the present embodiment is performed by a difference
between the inertance L1 (also referred to as a combined inertance
L1 in some cases) on the entrance channel side and the inertance L2
(also referred to as a combined inertance L2 in some cases) on the
exit channel side.
[0112] Firstly, the inertance will be explained.
[0113] The inertance L is expressed as L=.rho..times.h/S assuming
that .rho. denotes the density of the fluid, S denotes the cross
section of the channel, and h denotes the length of the channel.
When assuming that the pressure difference of the channel is
.DELTA.P, and the flow rate of the fluid flowing through the
channel is Q, by transforming the motion equation in the channel
using the inertance L, the relationship of .DELTA.P=L.times.dQ/dt
is derived.
[0114] In other words, the inertance L represents the degree of the
influence exerted on the time variation of the flow rate, and the
larger the inertance L is, the smaller the time variation of the
flow rate is, and the smaller the inertance L is, the larger the
time variation of the flow rate is.
[0115] Further, a combined inertance with respect to a parallel
connection of a plurality of channels or a series connection of a
plurality of channels with shapes different from each other can be
calculated by combining the inertances of the respective channels
in substantially the same manner as the parallel connection or the
series connection of inductances in an electrical circuit.
[0116] It should be noted that regarding the inertance L1 on the
entrance channel side, since the connection channel 504 is set to
have a diameter sufficiently larger than that of the entrance
channel 503, the inertance L1 can be obtained by calculating only
the inertance of the entrance channel 503. Further, the connection
tube for connecting the pump 20 and the entrance channel has
flexibility, and therefore, is omitted from the calculation of the
inertance L1.
[0117] Further, regarding the inertance L2 on the exit channel
side, in the case in which the diameter of the connection channel
201 is far larger than that of the exit channel, and the thickness
of the tube portion (tube wall) of the connection channel tube 200
is small, the influence on the inertance L2 is minimal. Therefore,
the inertance L2 on the exit channel side can be replaced by the
inertance of the exit channel 511.
[0118] In the case in which the thickness of the tube wall of the
connection channel tube 200 is large, the inertance L2 is obtained
as the combined inertance of the exit channel 511, the connection
channel 201, and the nozzle 211.
[0119] Further, in the present embodiment, the channel length and
the cross section of the entrance channel 503 and the channel
length and the cross section of the exit channel 511 are set so
that the inertance L1 on the entrance channel side becomes larger
than the inertance L2 on the exit channel side.
[0120] Hereinafter, a detailed configuration of the drive section
30 will be explained with reference to FIGS. 5 through 7.
[0121] Here, FIG. 5 is a block diagram showing a detailed
configuration of the drive section 30. Further, FIG. 6 is a
flowchart showing a process of generating a signal waveform in the
drive section 30. Still further, FIG. 7 is a flowchart showing a
process of supplying the pulsation generation section 100 with a
drive signal in the drive section 30.
[0122] As shown in FIG. 5, the drive section 30 is configured
including an operation control section 30a, a signal waveform
generation section 30b, a data storage section 30c, a drive signal
supply section 30d, and a sync signal generation section 30e.
[0123] The operation control section 30a assumes the role of
providing each of the constituents with an operational instruction
in accordance with an operational input from an input device (not
shown) of the fluid jet device 1, and has a function of controlling
various kinds of operational processes such as a process of
generating the signal waveform, or a process of supplying the drive
signal.
[0124] The signal waveform generation section 30b has a function of
generating a signal waveform with a shape suitable for driving the
pulsation generation section 100 using the waveform information, a
data table, and measurement data stored in the data storage section
30c based on the jet emission intensity of the fluid jet emitting
section 2, which is set based on the input information of the user
via the input device.
[0125] Specifically, as a signal waveform corresponding to one
cycle of the drive signal, there is generated a signal waveform
configured including a compressing drive waveform section for
operating the piezoelectric element 401 so as to compress the
capacity of the fluid chamber 501, and a restoring drive waveform
section for operating the piezoelectric element 401 so as to
restore the capacity of the fluid chamber 501, which is in the
compressed state, to the state prior to the compression.
[0126] The signal waveform generation section 30b of the present
embodiment is arranged to generate the signal waveform composed of
the compressing drive waveform section and the restoring drive
waveform section satisfying the following formula 1.
[0127] Here, the time length of the compressing signal waveform
section is denoted as T.sub.red, and the time length of the
restoring drive waveform section is denoted as T.sub.exp. Further,
average pressure in the fluid chamber 501 in a period of supplying
the compressing drive waveform section is denoted as P.sub.gen, and
pressure applied to the entrance channel 503 in the fluid chamber
501 on the pump 20 side in a period of supplying the restoring
drive waveform section is denoted as P.sub.sup.
T.sub.red.times.(P.sub.gen-P.sub.sup).ltoreq.T.sub.exp.times.P.sub.sup
(1)
[0128] Hereinafter, the formula 1 described above will be
explained.
[0129] When denoting the cross section of the entrance channel 503
as S, the momentum M.sub.g acting on the entrance channel on the
fluid chamber 501 side is expressed as
"M.sub.g=S.times.T.sub.red.times.(P.sub.gen-P.sub.sup)." On the
other hand, the momentum Ms acting on the entrance channel 503 on
the pump 20 side is expressed as
"M.sub.s=S.times.T.sub.exp.times.P.sub.sup." Further, in the fluid
jet emitting section 2 with the configuration described above, it
is known that P.sub.sup usually takes a value far smaller than
P.sub.gen (P.sub.gen>>P.sub.sup). Therefore, it is also
possible to neglect P.sub.sup in the formula 1 described above.
[0130] Further, in a period (the period of T.sub.exp) during which
the capacity of the fluid chamber 501 is expanding (restoring the
original capacity), the average pressure of the fluid chamber 501
becomes 0 atm or nearly 0 atm (hereinafter, this pressure state is
referred to as a vacuum state) because the fluid is drawn due to
the inertance of the exit channel 511.
[0131] In other words, if the momentum M.sub.s provided thereto in
the period of T.sub.exp is equal to or larger than the momentum
M.sub.g provided thereto in the period of T.sub.red, the fluid can
be restored to the original steady state.
[0132] Here, the steady state denotes the state in which the fluid
flows through the fluid chamber 501 while the supply pressure from
the pump 20 and the fluid resistance of the entire channel balance
with each other.
[0133] Therefore, by supplying the piezoelectric element 401
forming the capacity varying section with the drive signal having a
signal waveform, which corresponds to one cycle thereof, and is
composed of the compressing drive waveform section with the time
length T.sub.red and the restoring drive waveform section with the
time length T.sub.exp satisfying the relationship of formula 1
described above, it is possible to restore the fluid to the
original steady state in a period corresponding to one cycle of the
drive signal. Thus, it is possible to prevent the compressing drive
waveform section in the subsequent cycle from being supplied to the
piezoelectric element 401 prior to returning to the steady state,
and therefore, the resulting degradation of the fluid jet force can
be prevented.
[0134] Further, by supplying the drive signal satisfying the
formula 1 described above, it is possible to gradually restore
(expand) the capacity of the fluid chamber 501 to the original
state effectively using the time necessary for restoring the flow
rate in the entrance channel 503. Thus, the expansion of the vacuum
bubble is prevented, and the gas emission to the vacuum bubble is
reduced, and therefore, it is possible to restore the steady state
in the condition in which substantially no gas bubble exists in the
fluid chamber 501. Thus, it becomes possible to reduce degradation
of the fluid jet force caused by degradation of the rigidity of the
fluid chamber 501 due to the gas bubbles.
[0135] The signal waveform generation section 30b of the present
embodiment is further arranged to generate the signal waveform
satisfying the formula 1 described above using the waveform
information of a plurality of types of sine waves with periods
different from each other stored in the data storage section 30c.
Here, the waveform information is the data (digital data) obtained
by sampling the signal levels (e.g., voltage values) of one cycle
of the plurality of types of sine wave signals at time intervals
.DELTA.t (shorter than one cycle).
[0136] Specifically, the signal waveform generation section 30b of
the present embodiment is arranged to generate the signal waveform
by combining the data of a part of each of two sine wave signals
with periods different from each other. For example, it generates
the signal waveform by splicing the anterior half cycle (T1/2
(.lamda.1/2)) of one sine wave and the posterior half cycle (T2/2
(.lamda.2/2)) of the other sine wave with each other.
[0137] It should be noted that regarding the waveform information
of the sine waves, it is possible to store one or some pieces of
basic information, and generate desired waveform information by
executing arithmetic processing on the basic information.
[0138] The signal waveform generation section 30b of the present
embodiment is used, for example, when performing the calibration of
the waveform information upon powering on, or in replacing the
fluid jet emitting section 2.
[0139] Therefore, the signal waveform generation section 30b has a
function of determining T.sub.red and T.sub.exp of the signal
waveform corresponding to the jet emission intensity set by the
user based on the measurement data from a pressure sensor (not
shown) capable of measuring the pressure of the fluid chamber 501,
the entrance channel 503, and so on provided to the fluid jet
emitting section 2.
[0140] Specifically, when generating the signal waveform, the
signal waveform generation section 30b first determines T.sub.red
corresponding to the jet emission intensity set by the user and
preliminary T.sub.exp based on a data table stored in the data
storage section 30c, and then, generates the drive signal waveform
based on T.sub.red and preliminary T.sub.exp. Subsequently, the
signal waveform generation section 30b drives the pulsation
generation section 100 (the piezoelectric element 401) with the
drive signal waveform, and measures P.sub.gen and P.sub.sup at that
moment based on the detection data of the pressure sensor. Further,
the signal waveform generation section 30b adjusts T.sub.exp so
that P.sub.gen and P.sub.sup thus measured satisfy the formula 1
described above. The signal waveform generation section 30b
thereafter repeatedly performs generation of the drive signal
waveform based on T.sub.red thus determined and T.sub.exp thus
adjusted, driving of the pulsation generation section 100 with the
signal waveform thus generated, and adjustment of T.sub.exp until
P.sub.gen and P.sub.sup thus measured satisfy the relationship of
the formula 1 described above.
[0141] Further, the data storage section 30c is configured
including a storage medium for storing waveform information
described above related to a plurality of types of sine waves with
periods and amplitudes different from each other, the data table
for determining T.sub.red and T.sub.exp corresponding to the jet
emission intensity thus set, and other data used for processing of
respective constituents, and has a function of reading out the data
stored in the storage medium in response to a read request from
each of the constituents and writing the data in the storage medium
in response to a write request from each of the constituents. In
other words, in addition to the function as the waveform
information storage section, the data storage section 30c also has
a function of storing other necessary data.
[0142] The drive signal supply section 30d has a function of
supplying the drive signal to the piezoelectric element 401 of the
capacity varying section forming the pulsation generation section
100 in sync with the sync signal from the sync signal generation
section 30e in response to a drive signal supply command from the
operation control section 30a.
[0143] Specifically, based on waveform designation information
included in the supply command, the drive signal supply section 30d
reads out the corresponding waveform information (digital waveform
data) from the data storage section 30c, executes DA conversion on
the waveform information thus read out to generate an analog drive
signal, and supplies the piezoelectric element 401 with the drive
signal thus generated in sync with the sync signal. It should be
noted that the waveform designation information corresponds, for
example, to identification information attached to the signal
waveform generated in the signal waveform generation section 30b
described above.
[0144] Further, it is arranged that when a halt command is input
from the operation control section 30a in the process of supplying
the drive signal, the supply of the drive signal is halted after
the entire waveform of one cycle in the midstream of the supply
process has been supplied to the piezoelectric element 401.
[0145] The sync signal generation section 30e includes an
oscillator such as a ceramic oscillator or a crystal oscillator, a
counter (or a PLL circuit), and so on, and has a function of
generating the sync signal based on a reference clock signal clk,
which is a signal output from the oscillator. Further, the sync
signal generation section 30e supplies the drive signal supply
section 30d with the reference clock signal and the sync
signal.
[0146] It should be noted that the drive section 30 is provided
with a computer system for realizing the functions of the
respective constituents described above with software, and for
executing the software for controlling the hardware necessary for
realizing the functions described above. Although the hardware
configuration of the computer system is not shown in the drawings,
there is adopted a configuration including a processor, a random
access memory (RAM), and a read only memory (ROM), and connecting
these elements with various internal and external buses.
[0147] Further, a display device such as a CRT or LCD monitor, and
an input device such as an operation panel, a mouse, or a keyboard
are coupled to the bus via an input/output interface (I/F) such as
IEEE1394, USB, or a parallel port.
[0148] Further, it is arranged that when powering on, a system
program stored in the ROM and so on loads various dedicated
computer programs on the RAM, which are previously stored in the
ROM, and for realizing the functions of the respective sections,
and the processor fully uses various resources along the
instructions described in the program loaded on the RAM to perform
predetermined controls and arithmetic processing, thereby realizing
the functions described above on the software.
[0149] Then, with reference to FIG. 6, the flow of the signal
waveform generation process in the signal waveform generation
section 30b will be explained.
[0150] When the processor executes the dedicated program to start
the signal generation process, the process first proceeds to the
step S100 as shown in FIG. 6.
[0151] In the step S100, whether or not a generation command of the
signal waveform from the operation control section 30a is input is
determined in the signal waveform generation section 30b, and if it
is determined that the command is input (Yes), the process proceeds
to the step S102, and otherwise (No) the determination process is
repeated until the command is input.
[0152] In the case of proceeding to the step S102, the signal
waveform generation section 30b displays a setting screen for fluid
jet emission intensity, and then the process proceeds to the step
S104.
[0153] In the step S104, whether or not the jet emission intensity
is set by the user via the input device is determined in the signal
waveform generation section 30b, and if it is determined that the
intensity is set (Yes), the process proceeds to the step S106, and
otherwise (No) the determination process is repeated until the
intensity is set.
[0154] In the case of proceeding to the step S106, the signal
waveform generation section 30b determines T.sub.red corresponding
to the jet emission intensity set in the step S104 based on the
data table, in which the time length T.sub.red of the compressing
signal waveform section corresponding to a predetermined jet
emission intensity is registered, and which is stored in the data
storage section 30c, and then the process proceeds to the step
3108.
[0155] In the step 3108, the signal waveform generation section 30b
determines preliminary T.sub.exp corresponding to the jet emission
intensity set in the step 3104 based on the data table, in which
the time length T.sub.exp of the restoring signal waveform section
corresponding to a predetermined type of jet emission intensity is
registered, and which is stored in the data storage section 30c,
and then the process proceeds to the step S110.
[0156] In the step S110, the signal waveform generation section 30b
reads out two types of waveform information corresponding
respectively to T.sub.red determined in the step S106 and T.sub.exp
preliminarily determined in the step S108 among a plurality of
types of sinusoidal waveform information stored in the data storage
section 30c, and then the process proceeds to the step S112.
[0157] In the step S112, the signal waveform generation section 30b
combines the anterior half cycle of one of the signal waveforms
generated based on the two types of waveform information read out
in the step S110 and the posterior half cycle of the other thereof
to generate one cycle of signal waveform, and then the process
proceeds to the step S114.
[0158] In the step 3114, the signal waveform generation section 30b
outputs, to the operation control section 30a, a drive request for
making the drive signal supply section 30d drive the pulsation
generation section 100 with the signal waveform generated in the
step S112, and then the process proceeds to the step S116.
[0159] In the step S116, the drive signal supply section 30d
outputs the drive signal obtained by DA-converting the digital
waveform signal (the waveform information) generated in the step
S112 into the analog waveform signal to the piezoelectric element
401 of the pulsation generation section 100 in sync with the sync
signal from the sync signal generation section 30e in response to
the drive command from the operation control section 30a, and then
the process proceeds to the step S118.
[0160] In the step S118, the signal waveform generation section 30b
measures the average pressure P.sub.gen in the fluid chamber 501
during the supply period of the compressing drive waveform section
and the pressure P.sub.sup applied to the entrance channel 503 in
the fluid chamber 501 on the pump 20 side during the supply period
of the restoring drive waveform section based on the detection data
from the pressure sensor provided to the fluid jet emitting section
2 in response to the supply of the drive signal to the
piezoelectric element 401 in the step S116, and then the process
proceeds to the step S120.
[0161] In the step S120, the signal waveform generation section 30b
determines whether or not P.sub.gen and P.sub.sup measured in the
step S118, and T.sub.red and T.sub.exp thus determined satisfy the
relationship of the formula 1 described above, and if it is
determined that the relationship is satisfied (Yes), the process
proceeds to the step S122, and otherwise (No) the process proceeds
to the step S128.
[0162] In the case of proceeding to the step S122, the signal
waveform generation section 30b stores the waveform information of
the signal waveform generated in the step S112 in the data storage
section 30c in correspondence with the identification information
unique to the waveform information, and then the process proceeds
to the step S124.
[0163] In the step S124, the signal waveform generation section 30b
outputs a drive halt request to the operation control section 30a,
and then the process proceeds to the step S126.
[0164] In the step S126, the drive signal supply section 30d stops
the supply of the drive signal after outputting the entire signal
waveform corresponding to one cycle, and the series of process is
terminated.
[0165] On the other hand, in the case in which the condition is not
satisfied, and the process proceeds to the step S128 in the step
S120, the signal waveform generation section 30b adjusts T.sub.exp
so as to satisfy the relationship of the formula 1 described above,
and then the process proceeds to the step S130.
[0166] In the step S130, the signal waveform generation section 30b
reads out two types of waveform information corresponding
respectively to T.sub.red determined in the step S106 and T.sub.exp
adjusted in the step S122 among a plurality of types of sinusoidal
waveform information stored in the data storage section 30c, and
then the process proceeds to the step S112.
[0167] It should be noted that it is also possible to set the fluid
jet emission intensity in the steps S102 and S104 by designating
the range corresponding to the performance of the fluid jet
emitting section 2. On this occasion, it should be arranged that
the process of the steps S106 through S124 is repeated for every
jet emission intensity in the range thus set.
[0168] Then, with reference to FIG. 7, the flow of the drive signal
supply process in the drive signal supply section 30d will be
explained.
[0169] When the processor executes the dedicated program to start
the drive signal supply process, the process first proceeds to the
step S200 as shown in FIG. 7.
[0170] In the step S200, the drive signal supply section 30d
determines whether or not a drive command from the operation
control section 30a is input, and if it is determined that the
command is input (Yes), the process proceeds to the step S202, and
otherwise (No) the process proceeds to the step S200.
[0171] In the case of proceeding to the step S202, the drive signal
supply section 30d sets the waveform information of the waveform
type used for driving the fluid jet emitting section 2 based on the
identification information of the designated waveform included in
the drive command, and then the process proceeds to the step
S204.
[0172] In the step S204, the drive signal supply section 30d reads
out the waveform information of the waveform type, which is set in
the step S202, from the data storage section 30c, and then the
process proceeds to the step S206.
[0173] In the step S206, the drive signal supply section 30d
outputs the drive signal obtained by DA-converting the digital
waveform signal thus read out into the analog waveform signal to
the piezoelectric element 401 of the pulsation generation section
100 in sync with the sync signal from the sync signal generation
section 30e, and then the process proceeds to the step S208.
[0174] In the step S208, the drive signal supply section 30d
determines whether or not a halt command is input from the
operation control section 30a, and if it is determined that the
command is input (Yes), the process proceeds to the step S210, and
otherwise (No) the output process of the drive signal in the step
S206 is continued.
[0175] In the case of proceeding to the step S210, the drive signal
supply section 30d stops the supply of the drive signal after
outputting the entire signal waveform corresponding to one cycle,
and then the process proceeds to the step S212.
[0176] In the step S212, the drive signal supply section 30d
determines whether or not a resume command is input from the
operation control section 30a, and if it is determined that the
command is input (Yes), the process proceeds to the step S206 to
resume the output process of the drive signal, and otherwise (No)
the process proceeds to the step S214.
[0177] In the case of proceeding to the step S214, whether or not a
termination command is input from the operation control section 30a
is determined, and if it is determined that the command is input
(Yes), the drive signal supply process is terminated, and otherwise
(No) the process proceeds to the step S212.
[0178] Then, with reference to FIG. 8, a specific operation of the
fluid jet device 1 of the present embodiment will be explained.
[0179] Here, FIG. 8 is a diagram showing an example of the signal
waveform generated by combining two types of sine waves.
[0180] Firstly, a specific operation of the signal waveform
generation process will be explained.
[0181] When a calibration instruction of the signal waveform from
the user is input to the drive section 30 via the input device, the
operation control section 30a outputs the generation command of the
signal waveform to the signal waveform generation section 30b.
[0182] Meanwhile, when receiving the generation command of the
signal waveform, the signal waveform generation section 30b
proceeds to the setting process of the fluid jet emission intensity
(the branch of "Yes" in the step S100).
[0183] The signal waveform generation section 30b first displays
(step S102) the setting screen of the fluid jet emission intensity
desired by the user on the display section not shown, thereby
prompting the user to set the jet emission intensity.
[0184] When the jet emission intensity is set (the branch of "Yes"
in the step S104) in accordance with the input information of the
user via the input device, the signal waveform generation section
30b determines (step S106) T.sub.red (corresponding to the nearest
value to the jet emission intensity thus set) corresponding to the
jet emission intensity thus set, based on the data table, which is
stored in the data storage section 30c, and for determining
T.sub.red.
[0185] Subsequently, the signal waveform generation section 30b
determines (step S108) preliminary T.sub.exp (corresponding to the
nearest value to the jet emission intensity thus set) corresponding
to the jet emission intensity thus set based on the data table,
which is stored in the data storage section 30c, and for
preliminarily determining T.sub.exp.
[0186] When T.sub.red and preliminary T.sub.exp are determined, the
signal waveform generation section 30b then reads out the waveform
information of the anterior half cycle of the sine wave sin 1 with
a period nearest to the double (e.g., 0.2 [ms]) of T.sub.red thus
determined and the waveform information of the posterior half cycle
of the sine wave sin 2 with a period nearest to the double of
preliminary T.sub.exp thus determined from the data storage section
30c (step S110).
[0187] Then, the signal waveform generation section 30b combines
the two types of waveform information thus read out, thereby
generating the waveform information of the signal waveform with the
compressing drive waveform section having the time length of
T.sub.red determined as described above, and the restoring drive
waveform section having the time length of T.sub.exp preliminarily
determined as described above (step S112).
[0188] When the signal waveform is generated, the signal waveform
generation section 30b outputs, to the operation control section
30a, the drive request for making the drive signal supply section
30d drive the piezoelectric element 401 of the pulsation generation
section 100 with the signal waveform thus generated (step
S114).
[0189] Thus, the operation control section 30a outputs, to the
drive signal supply section 30d, the drive signal supply command
for supplying the drive signal of the signal waveform thus
generated to the piezoelectric element 401.
[0190] Meanwhile, when receiving the drive signal supply command of
the signal waveform thus generated as described above from the
operation control section 30a, the drive signal supply section 30d
executes the DA conversion on the waveform information included in
the drive signal supply command in sync with the sync signal from
the sync signal generation section 30e, and then outputs the analog
signal obtained by executing the DA conversion to the piezoelectric
element 401 of the pulsation generation section 100 as the drive
signal (step S116).
[0191] When supply of the drive signal to the piezoelectric element
401 is started, the signal waveform generation section 30b measures
the average pressure P.sub.gen in the fluid chamber 501 and the
pressure P.sub.sup applied to the entrance channel 503 in the fluid
chamber 501 on the pump 20 side, based on the detection data from
the pressure sensor provided to the fluid jet emitting section 2
(step S118).
[0192] Then, the signal waveform generation section 30b determines
whether or not P.sub.gen and P.sub.sup thus measured satisfy the
relationship of the formula 1 described above (step S120).
[0193] For example, it is assumed that P.sub.gen=12 atm (1.2 MPa)
and P.sub.sup=2 atm (0.2 MPa) are obtained based on the detection
data of the pressure sensor.
[0194] On this occasion, according to the formula 1 described
above, "0.1.times.(12-2) T.sub.exp.times.2," namely
"0.5.ltoreq.T.sub.exp" is obtained. Therefore, if T.sub.exp is no
larger than 0.5 [ms], it is determined that the relationship of the
formula 1 described above is not satisfied (the branch of "No" in
the step S120).
[0195] For example, if present T.sub.exp is 0.4 [ms], it is
determined that the relationship of the formula 1 described above
is not satisfied, and an adjustment such as adding 0.1 [ms] to
present T.sub.exp (0.4 [ms]) is executed (step S128). Further, the
signal waveform generation section 30b reads out the waveform
information corresponding to T.sub.red thus determined and
T.sub.exp thus adjusted as described above from the data storage
section 30c (step S130), and then the waveform information with
adjusted T.sub.exp is generated based on the waveform information
described above (step S112).
[0196] Specifically, as illustrated by a heavy line in FIG. 8,
there is generated a combined waveform obtained by connecting the
maximum value of the anterior half cycle (.lamda./2) of the sine
wave sin 1 forming the compressing drive waveform section Wc in one
cycle of the signal waveform, and the maximum value of the
posterior half cycle (.lamda./2) of the sine wave sin 2 forming the
restoring drive waveform section Wr therein.
[0197] The signal waveform generation section 30b outputs a drive
request to the operation control section 30a so as to drive the
piezoelectric element 401 with the signal waveform of the waveform
information thus generated (step S114). Thus, the piezoelectric
element 401 is driven with the signal waveform thus adjusted (step
S116), and P.sub.gen and P.sub.sup are measured again based on the
detection data of the pressure sensor (step S118).
[0198] Then, if P.sub.gen=12 atm (1.2 MPa) and P.sub.sup=2 atm (0.2
MPa) are obtained, since T.sub.red has been set to be 0.1 [ms] and
T.sub.exp has been set to be 0.5 [ms] in this case, it is
determined that the relationship of the formula 1 described above
is satisfied (the branch of "Yes" in the step S120).
[0199] When it is determined that T.sub.red and T.sub.exp satisfy
the relationship of the formula 1 described above, the signal
waveform generation section 30b stores the waveform information of
one cycle of the signal waveform corresponding to these T.sub.red
and T.sub.exp into the data storage section 30c in correspondence
with the identification information (step S122).
[0200] It should be noted that on this occasion, it is also
possible to determine T.sub.exp to be a value equal to or larger
than 0.5 [ms] with respect to T.sub.red of 0.1 [ms].
[0201] Further, the waveform information is not limited to be of
one cycle, but it is also possible to arrange that a plurality of
cycles of waveform information is stored. In this case, in the
waveforms each corresponding to one cycle and adjacent to each
other, the lowest value of the compressing drive waveform section
of one of the waveforms and the lowest value of the restoring drive
waveform section of the other of the waveforms are connected to
each other.
[0202] When the waveform information satisfying the relationship of
the formula 1 is stored, the signal waveform generation section 30b
outputs, to the operation control section 30a, the drive halt
request for stopping the piezoelectric element 401 in operation
(step S124).
[0203] Thus, the operation control section 30a outputs, to the
drive signal supply section 30d, a drive signal supply halt command
for stopping the supply of the drive signal to the piezoelectric
element 401.
[0204] Meanwhile, when receiving the drive signal supply halt
command from the operation control section 30a, the drive signal
supply section 30d stops supplying the drive signal after
outputting one whole cycle of the signal waveform.
[0205] Then, a specific operation of the drive signal supply
process will be explained.
[0206] When the user holds down a drive switch (not shown), and the
drive signal supply instruction is input to the drive section 30,
the operation control section 30a outputs the drive signal supply
command to the drive signal supply section 30d.
[0207] Meanwhile, when receiving the drive signal supply command,
the drive signal supply section 30d proceeds to the waveform
information setting process (the branch of "Yes" in the step
S200).
[0208] Since the drive signal supply command includes designated
waveform information including the identification information of
the waveform information used as the drive signal, the drive signal
supply section 30d sets the waveform information with the
identification information corresponding to the designated waveform
information as the waveform information used for driving (step
S202). Here, it is assumed that the waveform information of the
signal waveform illustrated by the heavy line shown in FIG. 8 and
generated as described above is set.
[0209] When the waveform information used as the drive signal is
set, the drive signal supply section 30d subsequently reads the
waveform information corresponding to the waveform information thus
set out from the data storage section 30c on a working memory such
as the RAM (step S204). Subsequently, the drive signal supply
section 30d executes the DA conversion on the waveform information
thus read out on the working memory in sync with the sync signal
from the sync signal generation section 30e, and outputs the analog
signal, which is thus converted in the DA conversion, to the
piezoelectric element 401 of the pulsation generation section 100
as the drive signal (step S206).
[0210] Before the drive signal is supplied, the pump 20 always
supplies the entrance channel 503 with the fluid at constant fluid
pressure. As a result, when the piezoelectric element 401 does not
operate, the fluid flows into the fluid chamber 501 due to the
difference between the ejection force of the pump 20 and the fluid
resistance value of the entire channel on the entrance channel
side.
[0211] Here, if the drive signal is input to the piezoelectric
element 401 and the piezoelectric element 401 rapidly expands in
the period of T.sub.red (0.1 [ms]), the pressure inside the fluid
channel 501 rises rapidly up to several tens of atm, providing the
inertances L1, L2 on the entrance channel side and the exit channel
side have sufficiently large values.
[0212] Since the pressure is far stronger than the pressure applied
by the pump 20 to the entrance channel 503, the inflow of the fluid
from the entrance channel side into the fluid chamber 501 is
reduced by the pressure, and the outflow thereof from the exit
channel 511 is increased.
[0213] However, since the inertance L1 of the entrance channel 503
is larger than the inertance L2 of the exit channel 511, and
therefore, the increased amount of the fluid ejected from the exit
channel is larger than the decreased amount of the amount of flow
of the fluid inflowing in the fluid chamber 501 from the entrance
channel 503, pulsed fluid ejection, namely a pulsation flow occurs
in the connection channel 201. The pressure pulsation in the
ejection operation propagates in the connection channel tube 200,
and thus the fluid jet is emitted from the fluid jet opening
section 212 of the nozzle 211 at the tip of the connection channel
tube 200.
[0214] Here, since the diameter of the fluid jet opening section
212 of the nozzle 211 is smaller than the diameter of the exit
channel 511, the fluid jet is emitted as a further high-pressure,
high-speed, and pulsed droplet.
[0215] Meanwhile, inside the fluid chamber 501, there is provided a
vacuum state immediately after the rise in pressure due to the
interaction between decrease in the amount of the fluid inflowing
from the entrance channel 503 and increase in the amount of the
fluid outflowing from the exit channel 511.
[0216] On the other hand, after the rise in pressure, in the period
of T.sub.exp (0.5 [ms]), the piezoelectric element 401 in the
expanded state slowly shrinks taking time five times as long as the
time T.sub.red (0.1 [ms]) in the expanding process. Thus, since the
expansion of the vacuum bubbles is prevented, the flow of the fluid
restores the steady state prior to the supply of the drive signal
while preventing generation of gases inside the fluid chamber
501.
[0217] It should be noted that due to the fact that the fluid
chamber 501 has a shape like a solid of revolution and is provided
with the entrance channel 503 and the fact that the exit channel
511 is opened in the vicinity of the rotational axis of the shape
like a solid of revolution, the swirling flow occurs in the fluid
chamber 501, and the bubbles (the vacuum bubbles and the gas
bubbles) included in the fluid are immediately discharged from the
exit channel 511 to the outside.
[0218] Therefore, by continuously supplying the piezoelectric
element 401 with the drive signal having the signal waveform
illustrated by the heavy line shown in FIG. 8, it is possible to
continuously emit jet of the pulsation flow from the nozzle 211 in
the state of maintaining strong jet force.
[0219] Further, as illustrated by the waveform of a thin line shown
in FIG. 8, the level of the drive current in the period of
T.sub.exp can be suppressed to a lower level compared to the level
of the drive current in the period of T.sub.red. Therefore, in the
case in which a bridge circuit or the like is used as the drive
circuit for driving the piezoelectric element 401, since a rated
value of the maximum peak current of a current emitting transistor
(e.g., the transistor on the low side) among the transistors used
in the circuit can be suppressed to a lower level, the cost for the
transistor can be reduced.
[0220] Further, since it is arranged that the signal waveform of
one cycle of drive signal is generated as a combination of sine
waves as illustrated by the waveform of the heavy line shown in
FIG. 8, it is possible to smoothly couple signal waveforms with
periods different from each other, and to reduce the stress to the
mechanism of the fluid jet emitting section 2.
[0221] Further, since the signal waveform generation section 30b is
capable of generating the waveform information of the appropriate
signal waveform in accordance with the values of P.sub.gen and
P.sub.sup of the fluid jet emitting section 2, it is possible to
easily perform replacement with a fluid jet emitting section with
different P.sub.gen and P.sub.sup.
Second Embodiment
[0222] Hereinafter, a second embodiment of the invention will be
explained with reference to the accompanying drawings. FIGS. 9A and
9B are diagrams showing a fluid jet device, a drive device of the
fluid jet device, a surgical instrument, and a method of driving
the fluid jet device according to the second embodiment of the
invention.
[0223] In comparison with the first embodiment described above, the
present embodiment is different therefrom in apart of the method of
forming the signal waveform satisfying the relationship of the
formula 1 in the signal waveform generation section 30b of the
drive section 30. Therefore, since the other part of the
configuration is substantially the same as in the drive section 30
of the first embodiment described above, hereinafter the different
part will be explained in detail, and the explanations of the
duplicated part will be omitted if appropriate.
[0224] The signal waveform generation section 30b of the present
embodiment is arranged to generate the signal waveform having a
waveform section disposed between the compressing drive waveform
section and the restoring drive waveform section by expanding a
part of the restoring drive waveform section, the waveform section
having an output level for driving the piezoelectric element 401 so
as to keep (stop the capacity variation) the capacity of the fluid
chamber 501 after the fluid chamber 501 is compressed.
[0225] Here, FIG. 91 is a diagram showing an example of a method of
expanding the waveform, and FIG. 9B is a diagram showing an example
of a signal waveform of a drive signal according to the present
embodiment.
[0226] Specifically, the signal waveform generation section 30b
generates the signal waveform of the waveform shape as shown in
FIG. 9B having the anterior half cycle t1 of the sine wave signal
shown in FIG. 9A as the compressing drive waveform section with the
time length T.sub.red (t1=T.sub.red) satisfying the relationship of
the formula 1 described above, a waveform section including an
extension section obtained by extending the period with the maximum
value in the posterior half cycle t2 (t1=t2) of the same sine wave
signal so as to be the period of T.sub.exp satisfying the
relationship of the formula 1 described above as the restoring
drive waveform section.
[0227] In other words, since the expansion of the vacuum bubble
becomes apt to occur by the rapid expansion of the capacity of the
fluid chamber 501 due to a rapid shrinkage operation subsequent to
the expansion operation (capacity compression operation) of the
piezoelectric element 401, by keeping the expanded state of the
piezoelectric element after the capacity compression operation, it
is possible to prevent the expansion of the vacuum bubbles and
generation of the gas bubbles. Further, since it leads to waiting
for the vacuum bubbles to disappear in the compressed state, it is
possible to make the vacuum bubbles disappear in a shorter period
of time than in the first embodiment described above, and
therefore, it is possible to restore the steady state in a shorter
period of time than in the first embodiment described above.
[0228] The flow of the signal waveform generation process of the
present embodiment will hereinafter be explained.
[0229] The signal waveform generation process of the present
embodiment is different from that of the first embodiment described
above only in the process content of the steps S110, S112, and S130
in the flowchart shown in FIG. 6, and the same in the process of
the other steps.
[0230] Hereinafter, the process of the steps S110 and S112 of the
present embodiment will be explained.
[0231] In the step S110, the signal waveform generation section 30b
reads out the waveform information corresponding to T.sub.red
determined in the step S106 among a plurality of types of
sinusoidal waveform information stored in the data storage section
30c, and then the process proceeds to the step S112.
[0232] In the step S112, the signal waveform generation section 30b
generates the signal waveform obtained by extending the posterior
half cycle of the waveform information read out in the step S110
based on T.sub.exp thus preliminarily determined in the step S108,
and the process proceeds to the step S114.
[0233] It should be noted that in the step S130 the signal waveform
obtained by extending the posterior half cycle of the waveform
information corresponding to T.sub.red based on T.sub.exp thus
adjusted.
[0234] Here, if the waveform information corresponding to T.sub.red
does not exist, the nearest one is read out, and then corrected for
use therein.
[0235] Then, with reference to FIGS. 9A and 9B, a specific
operation of the fluid jet device 1 of the present embodiment will
be explained.
[0236] Firstly, a specific operation of the signal waveform
generation process will be explained.
[0237] Since the determination process of T.sub.red and the
preliminary determination process of T.sub.exp are the same as in
the first embodiment described above, the process subsequent to the
determination will be explained.
[0238] When T.sub.red and preliminary T.sub.exp are determined, the
signal waveform generation section 30b then reads out the waveform
information of the anterior half cycle of the sine wave sin 1
having one cycle the nearest to the double (e.g., 0.2 [ms]) of
T.sub.red thus determined from the data storage section 30c (step
S110).
[0239] Subsequently, the signal waveform generation section 30b
generates the waveform information of the signal waveform obtained
by extending the period with the maximum value in the posterior
half cycle in the waveform information thus read out so that the
posterior half cycle becomes to have a period equal to or longer
than at least T.sub.exp thus preliminarily determined (step
S112).
[0240] Since the subsequent process (steps S114 through S120, and
S128) is substantially the same as in the first embodiment, the
process after adjusting T.sub.exp in the step S128 will be
explained.
[0241] After adjusting T.sub.exp, the signal waveform generation
section 30b reads out the waveform information of a trapezoidal
wave corresponding to the cycle double of T.sub.red thus determined
as described above from the data storage section 30c (step S130),
and corrects the waveform information thus read out so that the
time length between nodal points C and E of the waveform
information becomes T.sub.exp thus adjusted, thereby generating the
waveform information after T.sub.exp is adjusted (step S112).
[0242] Then, the signal waveform generation section 30b outputs the
drive request (step S114) to make the drive signal supply section
30d drive the piezoelectric element 401 with the signal waveform of
the waveform information thus generated (step S116).
[0243] When the drive signal is supplied to the piezoelectric
element 401, the signal waveform generation section 30b measures
P.sub.gen and P.sub.sup (step S118), and determines whether or not
the measurement results, T.sub.red, and T.sub.exp thus adjusted
satisfy the relationship of the formula 1 described above (step
S120).
[0244] In the determination, if the waveform information with
T.sub.exp adjusted satisfies the relationship of the formula 1
described above (the branch of "Yes" in the step S120), the signal
waveform generation section 30b stores the waveform information
into the data storage section 30c in correspondence with the
identification number (step S122). The subsequent process of the
steps S124 and S126 is substantially the same as in the first
embodiment, and therefore the explanations therefor will be
omitted.
[0245] When T.sub.exp is adjusted so as to satisfy the relationship
of the formula 1 described above, the signal waveform generation
section 30b reads out the waveform information corresponding to
T.sub.red thus determined as described above from the data storage
section 30c (step S130), and extends the posterior half cycle of
the waveform information, thus read out, based on T.sub.exp thus
adjusted, thereby generating the waveform information with
T.sub.exp adjusted (step S112).
[0246] Specifically, as shown in FIG. 9B, the signal waveform
generation section 30b generates the signal waveform with the
waveform shape in which the period with the maximum value of the
restoring drive waveform section continues for about 0.4 [ms].
[0247] The waveform information of the signal waveform
corresponding to one cycle thus generated is stored in the data
storage section 30c in correspondence with the identification
number (step S122). It should be noted that the waveform
information is not limited to be of one cycle, but it is also
possible to arrange that a plurality of cycles of waveform
information is stored. In this case, in the waveforms each
corresponding to one cycle and adjacent to each other, the lowest
value of the compressing drive waveform section of one of the
waveforms and the lowest value of the restoring drive waveform
section of the other of the waveforms are connected to each
other.
[0248] The operation of the drive signal supply process is
substantially the same as in the first embodiment described above,
and therefore the explanations therefor will be omitted.
[0249] As described above, by supplying the drive signal with the
signal waveform shown in FIG. 9B thus generated as described above
to the piezoelectric element 401 of the pulsation generation
section 100 to keep the expanded state of the piezoelectric element
after rapidly expanding the piezoelectric element to compress the
capacity of the fluid chamber 501 in the period of the compressing
drive waveform section for 0.1 [ms], it is possible to prevent the
expansion of the vacuum bubbles, and consequently generation of the
gas bubbles.
Third Embodiment
[0250] Hereinafter, a third embodiment of the invention will be
explained with reference to the accompanying drawings. FIGS. 10
through 14 are diagrams showing a fluid jet device, a drive device
of the fluid jet device, a surgical instrument, and a method of
driving the fluid jet device according to the third embodiment of
the invention.
[0251] In comparison with the first and second embodiments, the
present embodiment is different therefrom in the content of the
waveform information stored in the data storage section 30c of the
drive section 30, a part of the method of generating the signal
waveform satisfying the relationship of the formula 1 described
above in the signal waveform generation section 30b of the drive
section 30, and the method of supplying the drive signal in the
drive signal supply section 30d of the drive section 30. Therefore,
since the other part of the configuration is substantially the same
as in the drive section 30 of the first and second embodiments
described above, hereinafter the different part will be explained
in detail, and the explanations of the duplicated part will be
omitted if appropriate.
[0252] The signal waveform generation section 30b of the present
embodiment has a function of generating a signal waveform to be a
trapezoidal wave with a shape suitable for determining T.sub.red
and T.sub.exp satisfying the relationship of the formula 1
described above using the waveform information of the trapezoidal
wave, a data table, and measurement data stored in the data storage
section 30c based on the jet emission intensity of the fluid jet
emitting section 2, which is set based on the input information of
the user via the input device, and driving the pulsation generation
section 100.
[0253] Specifically, similarly to the case of the first embodiment,
the signal waveform generation section 30b generates the signal
waveform of the trapezoidal wave having the compressing drive
waveform section of the time length T.sub.red and the restoring
drive waveform section of the time length T.sub.exp satisfying the
relationship of the formula 1 described above. Then, the signal
waveform generation section 30b stores the nodal information of the
trapezoidal wave thus generated into the data storage section 30c
as the waveform information.
[0254] The data storage section 30c of the present embodiment is
configured including a storage medium for storing the nodal
information (time, voltage levels) of one cycle of a plurality of
types of trapezoidal waves with periods and amplitudes different
from each other as the waveform information, and in addition, other
data used for processing of respective constituents, and has a
function of reading out the data stored in the storage medium in
response to a read request from each of the constituents and
writing the data in the storage medium in response to a write
request from each of the constituents.
[0255] Then, with reference to FIG. 10, a detailed configuration of
the drive signal supply section 30d of the present embodiment will
be explained.
[0256] Here, FIG. 10 is a block diagram showing the detailed
configuration of the drive signal supply section 30d according to
the present embodiment.
[0257] As shown in FIG. 10, the drive signal supply section 30d of
the present embodiment has a configuration including an
interpolation section 31, a counter 33, and an amplifier 35.
[0258] The interpolation section 31 has a function of reading out
the nodal information of the trapezoidal wave used as the drive
signal from the data storage section 30c in response to the drive
signal supply command from the operation control section 30a, and
then setting an operating condition of the counter 33 for supplying
the pulsation generation section 100 with the drive signal based on
the nodal information.
[0259] Here, FIG. 11 is a diagram showing an example of the
trapezoidal wave forming the drive signal.
[0260] The data storage section 30c stores the voltage information
and the time information of each of the nodal points A through E of
the trapezoidal wave shown in FIG. 11 as the waveform information.
The waveform information of the nodal points A through C forms the
compressing drive waveform section, and the waveform information of
the nodal points C through E forms the restoring drive waveform
section. Further, in the case in which the time information is the
information of the absolute time, T.sub.red is defined as the time
period corresponding to the difference obtained by subtracting the
absolute time of the nodal point A from the absolute time of the
nodal point C, and T.sub.exp is defined as the time period
corresponding to the difference obtained by subtracting the
absolute time of the nodal point C from the absolute time of the
nodal point E.
[0261] Further, the operating condition of the counter corresponds
to a condition for interpolating the waveform data between the
nodal points adjacent to each other with the resolution of the
clock signal clk using the waveform information of each of the
nodal points, and then performing the DA conversion from the
information of each of the nodal points of the trapezoidal wave
into the signal information of the continuous analog trapezoidal
wave. Therefore, as the operating condition of the counter, an
initial value of counting, the number of times (the time direction)
of increase and decrease of counting, an amount (the voltage
direction) of increase and decrease of counting, and so on are
set.
[0262] The counter 33 has a function of performing counting
operation of the clock signal elk from the sync signal generation
section 30e based on the operating condition set by the
interpolation section 31, and then outputting the signal of the
count value corresponding to the operating condition to the
amplifier 35.
[0263] The amplifier 35 has a function of amplifying the signal
input from the counter 33 to be in a level appropriate for driving
the piezoelectric element 401, and then outputting it to the
piezoelectric element 401 of the pulsation generation section
100.
[0264] Then, with reference to FIG. 12, the flow of the drive
signal supply process in the drive signal supply section 30d of the
present embodiment will be explained.
[0265] Here, FIG. 12 is a flowchart showing a process
(corresponding to the steps S204 and S206 of the first embodiment
described above) of outputting the drive signal in the drive signal
supply process of the present embodiment.
[0266] When the drive signal output process is started, as shown in
FIG. 12, the process firstly proceeds to the step S300.
[0267] In the step S300, the interpolation section 31 sets a start
address of the waveform information, which is set as the drive
signal, in a data look-up address A, and then the process proceeds
to the step S302.
[0268] In the step S302, the interpolation section 31 reads the
time data "read (A, 1)" at the address A into a variable T(1), and
then the process proceeds to the step S304.
[0269] Thus, "T(1)=read (A, 1)" is obtained.
[0270] In the step S304, the interpolation section 31 reads the
waveform data "read (A, 2)" at the address A into a variable D(1),
and then the process proceeds to the step S306.
[0271] Thus, "D(1)=read (A, 2)" is obtained.
[0272] In the step 3306, the interpolation section 31 sets the
value of D(1), which is read in the step S304, in a variable cut as
the initial value of the counter, and then the process proceeds to
the step S308.
[0273] Thus, "cnt=D(1)=read (A, 2)" is obtained.
[0274] In the step S308, the interpolation section 31 executes a
counter condition setting process described later to set the
counter condition, and then the process proceeds to the step
S310.
[0275] In the step S310, the interpolation section 31 determines
whether or not the sync signal is detected, and if it is determined
that the sync signal is detected (Yes), the process proceeds to the
step S312, and otherwise (No) the determination process is repeated
until the sync signal is detected.
[0276] If the process proceeds to the step S312, the interpolation
section 31 sets "0" in a variable k, and then the process proceeds
to the step S314. Here, the variable k is a variable for counting
the number of times of the counting by the counter.
[0277] In the step S314, the counter 33 determines whether or not
the value of the variable k is smaller than the value of a variable
N, and if it is determined that it is smaller (Yes), the process
proceeds to the step S316, and otherwise (No) the process proceeds
to the step S322. Here, the variable N is a variable in which the
number of times of the counting in the time axis necessary for
moving from a certain nodal point to the next nodal point is set,
and is set in the counter condition setting process described
later.
[0278] If the process proceeds to the step S316, the counter 33
outputs the signal waveform to the amplifier 35, and then the
process proceeds to the step S318.
[0279] In the step S318, the interpolation section 31 adds the
value of a variable S to the present value of the variable cnt, and
then the process proceeds to the step S320. Here, the variable S is
a variable in which the amount of increase and decrease of the
counting in the voltage axis in each counting operation in a period
from a certain nodal point to the next nodal point is set, and is
set in the counter condition setting process described later. If
the value of the variable S is a positive number, the counter 33
counts up the value of the variable S, and if the value of the
variable S is a negative number, the counter 33 counts down the
absolute value of the variable S.
[0280] In the step S320, the interpolation section 31 adds 1 to the
present value of the variable k, and then the process proceeds to
the step S314.
[0281] On the other hand, if the value of the variable k exceeds
the value of the variable N in the step S314, and the process
proceeds to the step S322, the interpolation section 31 determines
whether or not the next nodal point data exists, and if it is
determined that it exists (Yes), the process proceeds to the step
S324, and otherwise (No) the series of process is terminated, and
the process returns to the original process.
[0282] If the process proceeds to the step S324, the interpolation
section 31 executes the counter condition setting process to set
the counter condition, and then the process proceeds to the step
S312.
[0283] Then, with reference to FIG. 13, the flow of the counter
condition setting process in the steps S308, S324 will be
explained.
[0284] Here, FIG. 13 is a flowchart showing the counter condition
setting process corresponding to the steps S308 and S324.
[0285] When the process proceeds to the step S308 or the step S324
and the counter condition setting process is started, the process
firstly proceeds to the step S400 as shown in FIG. 13.
[0286] In the step S400, the interpolation section 31 adds 1 to the
value of the data look-up address A, and then the process proceeds
to the step S402.
[0287] In the step S402, the interpolation section 31 reads the
time data at the address A into a variable T(2), and then the
process proceeds to the step S404.
[0288] Thus, "T(2)=read (A, 1)" is obtained.
[0289] In the step S404, the interpolation section 31 reads the
waveform data at the address A into a variable D(2), and then the
process proceeds to the step S406.
[0290] Thus, "D(2)=read (A, 2)" is obtained.
[0291] In the step S406, the interpolation section 31 substitutes
the value obtained by dividing the value, which is obtained by
subtracting the value of the variable T(1) from the value of the
variable T(2), by the time (t_clk) of one cycle of the clock signal
clk for the variable N as the number of times of counting in the
time axis necessary for reaching the next nodal point, and then the
process proceeds to the step S408.
[0292] In the step S408, the interpolation section 31 subtracts the
value of the variable D(1) from the value of the variable D(2), and
substitutes the value obtained by dividing the result of the
subtraction by the value of the variable N for the variable S as
the amount of increase and decrease of the counting in the voltage
axis in each counting operation, and then the process proceeds to
the step S410.
[0293] In the step S410, the interpolation section 31 substitutes
the value of the variable T(2) for the variable T(1), and the value
of the variable D(2) for the variable D(1), then the series of
process is terminated, and the process returns to the original
process.
[0294] Then, with reference to FIGS. 14 and 15, a specific
operation of the fluid jet device 1 of the present embodiment will
be explained.
[0295] Here, FIG. 14 is a diagram showing an example of the
waveform information of the present embodiment. Further, FIG. 15 is
a diagram showing an output example of the drive signal of the
trapezoidal wave.
[0296] Since the determination process of T.sub.red and the
preliminary determination process of T.sub.exp are the same as in
the first embodiment described above, the process subsequent to the
determination will be explained.
[0297] When T.sub.red and preliminary T.sub.exp are determined, the
signal waveform generation section 30b then reads out the waveform
information of the trapezoidal wave having one cycle the nearest to
the double (e.g., 0.2 [ms]) of T.sub.red thus determined from the
data storage section 30c (step S110).
[0298] Here, in the case in which the time length between the nodal
points A and E in the waveform information of the trapezoidal wave
thus read out is different from T.sub.red thus determined as
described above, the time information of the waveform information
thus read out is corrected.
[0299] Then, the time length between the nodal points C and E in
the waveform information of the trapezoidal wave thus read out as
described above is corrected so as to be equal to or longer than
T.sub.exp thus preliminarily determined. In the manner as described
above, by correcting the waveform information of a single type of
trapezoidal wave, the waveform information of the trapezoidal
signal waveform is generated (step S112).
[0300] It should be noted that as another method of generating the
trapezoidal signal waveform, there can be cited a method of
generating the signal waveform by combining the anterior half cycle
of one of the waveform information of two types of trapezoidal
waves with periods different from each other with the posterior
half cycle of the other thereof as in the case of the first
embodiment described above. Further, regarding the correction of
the time length between the nodal points A and E, similarly to the
case described above, there is cited a method of performing the
correction by expending the time length between the nodal points C
and D as in the second embodiment described above when correcting
the time length between the nodal points C and E.
[0301] Since the subsequent process (steps 3114 through S120, and
S128) is substantially the same as in the first embodiment, the
process after adjusting T.sub.exp in the step S128 will be
explained.
[0302] After adjusting T.sub.exp, the signal waveform generation
section 30b reads out the waveform information of a trapezoidal
wave corresponding to the cycle double of T.sub.red thus determined
as described above from the data storage section 30c (step S130),
and corrects the waveform information thus read out so that the
time length between nodal points C and E of the waveform
information becomes T.sub.exp thus adjusted, thereby generating the
waveform information after T.sub.exp is adjusted (step S112).
[0303] Then, the signal waveform generation section 30b outputs the
drive request (step S114) to make the drive signal supply section
30d drive the piezoelectric element 401 with the signal waveform of
the waveform information thus generated (step S116).
[0304] When the drive signal is supplied to the piezoelectric
element 401, the signal waveform generation section 30b measures
P.sub.gen and P.sub.sup (step S118), and determines whether or not
the measurement results, T.sub.red, and T.sub.exp thus adjusted
satisfy the relationship of the formula 1 described above (step
S120).
[0305] If the waveform information of one cycle of the signal
waveform thus generated satisfies the relationship of the formula 1
described above (the branch of "Yes" in the step S120), the signal
waveform generation section 30b stores the waveform information
into the data storage section 30c in correspondence with the
identification number (step S122).
[0306] The operation of the drive signal supply process will
hereinafter be explained.
[0307] When the user holds down a drive switch (not shown), and the
drive signal supply instruction is input to the drive section 30,
the operation control section 30a outputs the drive signal supply
command to the drive signal supply section 30d.
[0308] Meanwhile, when receiving the drive signal supply command,
the drive signal supply section 30d proceeds to the waveform
information setting process (the branch of "Yes" in the step
S200).
[0309] Since the drive signal supply command includes designated
waveform information including the identification information of
the waveform information used as the drive signal, the drive signal
supply section 30d sets the waveform information with the
identification information corresponding to the designated waveform
information as the waveform information used for driving (step
S202). Here, it is assumed that the waveform information shown in
FIG. 14 is set.
[0310] When the waveform information used as the drive signal is
set, then the interpolation section 31 sets the start address 101
in the data look-up address A (step S300), and subsequently reads
the time data t0 at the address 101 into the variable T(1) (step
S302). Thus, "T(1)=t0" is obtained.
[0311] Subsequently, the interpolation section 31 reads the
waveform data P0 at the address 101 into the variable D(1) (step
S304). Thus, "D(1)=P0" is obtained.
[0312] Then, the interpolation section 31 sets the value P0 of the
variable D(1) in the variable cnt as the initial value of the
counter (step S306), and the process proceeds to the counter
condition setting process (step S308).
[0313] When the counter condition setting process is started, the
interpolation section 31 firstly adds 1 to the value of the data
look-up address A (step S400). Thus, "A=102" is obtained.
[0314] Subsequently, the interpolation section 31 reads the time
data t1 at the address 102 into the variable T (2) (step S402), and
the waveform data P1 at the address 102 into the variable D(2)
(step S404). Thus, "T (2)=t1, D (2)=P1" is obtained.
[0315] Then, the interpolation section 31 subtracts the value t0 of
the variable T (1) from the value t1 of the variable T (2),
calculates the number of times of the counting in the time axis by
dividing the result of the subtraction by the time (t_clk) of one
cycle of the clock signal clk, and substitutes the calculation
result "(t1-t0)/t_clk" for the variable N. Thus, "N=(t1-t0)/t_elk"
is obtained.
[0316] Subsequently, the interpolation section 31 subtracts the
value P0 of the variable D(1) from the value P1 of the variable
D(2), calculates the amount of increase and decrease of the counter
in the voltage axis by dividing the result of the subtraction by
the number of times N of the counting, and substitutes the
calculation result "(P1-P0)/N" for the variable S. Thus,
"S=(P1-P0)/N" is obtained.
[0317] Lastly, the interpolation section 31 substitutes the value
t1 of the variable T(2) for the variable T(1), and the value P1 of
the variable D(2) for the variable D(1), then the counter condition
setting process is terminated, and the process returns to the
original process (step S410). Thus, "T(1)=t1," "D(1)=P1" are
obtained.
[0318] When the counter condition with respect to the counter 33 is
set, then the interpolation section 31 waits for the sync signal
from the sync signal generation section 30e to be detected, and if
the sync signal is detected (the branch of "Yes" in the step S310),
the interpolation section 31 initializes the variable k by setting
"0" therein, and compares the value "0" of the variable k with the
value "(t1-t0)/t_clk" of the variable N to determine whether or not
the value of the variable k is smaller than the value of the
variable N (step S314).
[0319] Then, in the period in which the value of the variable k is
smaller than the value of the variable N (the branch of "Yes" in
the step S314), the signal waveform with the voltage value
determined by the value of the variable cnt is output from the
counter 33 to the amplifier 35 in every clock (step S316), then the
value of the variable S is added to the value of the variable cnt
(step S318), and then 1 is added to the value of the variable k
(step S320).
[0320] Since in the example shown in FIG. 15 P0 and P1 are set to
be "0[V]," the amount S of increase and decrease of the counter
becomes "0," and therefore, even if the value of the variable k
increases, the value of the variable cnt is kept to the initial
value of "0." Therefore, the counter 33 keeps outputting the signal
waveform of "0[V]" to the amplifier 35 while the value of the
variable k is kept smaller than the value of the variable N.
[0321] Subsequently, when the value of the variable k exceeds the
value of the variable N (the brunch of "No" in the step S314),
since the next nodal point data exists here (the branch of "Yes" in
the step S322), the process proceeds to the counter condition
setting process again (step S324).
[0322] Similarly to the above, after executing the process of the
steps S400 through S410, "A=103," "T(2)=t2," "D(2)=P2,"
"N=(t2-t1)/t_clk," "S=(P2-P1)/N," "T(1)=t2," and "D(1)=P2" are
obtained.
[0323] When the counter condition with respect to the counter 33 is
set, then the interpolation section 31 waits for the sync signal
from the sync signal generation section 30e to be detected, and if
the sync signal is detected (the branch of "Yes" in the step S310),
the interpolation section 31 initializes the variable k by setting
"0" therein, and compares the value "0" of the variable k with the
value "(t2-t1)/t_clk" of the variable N to determine whether or not
the value of the variable k is smaller than the value of the
variable N (step S314).
[0324] Then, in the period in which the value of the variable k is
smaller than the value of the variable N (the branch of "Yes" in
the step S314), the signal waveform with the voltage value
determined by the value of the variable cat is output from the
counter 33 to the amplifier 35 in every clock (step S316), then the
value of the variable S is added to the value of the variable cat
(step S318), and further 1 is added to the value of the variable k
(step S320).
[0325] Since in the example shown in FIG. 15, P2 is set to be a
"value (assumed to be 3[V] here) larger than 0[V]," the amount S of
increase and decrease of the counter becomes "(3/N) [V]," and the
value of the variable cnt increases by "(3/N) [V]" every time the
value of the variable k increases by 1. Therefore, the counter 33
outputs the signal waveform, which increases by "(3/N) [V]" every
time the value of the variable k increases by "1," to the amplifier
35.
[0326] Subsequently, when the value of the variable k exceeds the
value of the variable N (the brunch of "No" in the step S314),
since the next nodal point data exists here (the branch of "Yes" in
the step S322), the process proceeds to the counter condition
setting process again (step S324).
[0327] Similarly to the above, after executing the process of the
steps S400 through S410, "A=104," "T(2)=t3," "D(2)=P3,"
"N=(t3-t2)/t_clk," "S=(P3-P2)/N," "T(1)=t3," and "D(1)=P3" are
obtained.
[0328] When the counter condition with respect to the counter 33 is
set, then the interpolation section 31 waits for the sync signal
from the sync signal generation section 30e to be detected, and if
the sync signal is detected (the branch of "Yes" in the step S310),
the interpolation section 31 initializes the variable k by setting
"0" therein, and compares the value "0" of the variable k with the
value "(t3-t2)/t_clk" of the variable N to determine whether or not
the value of the variable k is smaller than the value of the
variable N (step S314).
[0329] Then, in the period in which the value of the variable k is
smaller than the value of the variable N (the branch of "Yes" in
the step S314), the signal waveform with the voltage value
determined by the value of the variable cnt is output from the
counter 33 to the amplifier 35 in every clock (step S316), then the
value of the variable S is added to the value of the variable cnt
(step S318), and further 1 is added to the value of the variable k
(step S320).
[0330] Since in the example shown in FIG. 15, P3 is set to be "the
same value 3[V] as that of P2," the amount S of increase and
decrease of the counter becomes "0[V]," and therefore, even if the
value of the variable k increases, the value of the variable cnt is
kept to "3[V]." Therefore, the counter 33 keeps outputting the
signal waveform of "3[V]" to the amplifier 35 while the value of
the variable k is kept smaller than the value of the variable N.
Therefore, the counter 33 outputs the signal waveform of "3 [V]" to
the amplifier 35 every time the value of the variable k increases
by "1."
[0331] Subsequently, when the value of the variable k exceeds the
value of the variable N (the brunch of "No" in the step S314),
since the next nodal point data exists here (the branch of "Yes" in
the step S322), the process proceeds to the counter condition
setting process again (step S324).
[0332] Similarly to the above, after executing the process of the
steps S400 through S410, "A=105," "T(2)=t4," "D(2)=P4,"
"N=(t4-t3)/t_clk," "S=(P4-P3)/N," "T(1)=t4," and "D(1)=P4" are
obtained.
[0333] When the counter condition with respect to the counter 33 is
set, then the interpolation section 31 waits for the sync signal
from the sync signal generation section 30e to be detected, and if
the sync signal is detected (the branch of "Yes" in the step S310),
the interpolation section 31 initializes the variable k by setting
"0" therein, and compares the value "0" of the variable k with the
value "(t4-t3)/t_clk" of the variable N to determine whether or not
the value of the variable k is smaller than the value of the
variable N (step S314).
[0334] Then, in the period in which the value of the variable k is
smaller than the value of the variable N (the branch of "Yes" in
the step S314), the signal waveform with the voltage value
determined by the value of the variable cnt is output from the
counter 33 to the amplifier 35 in every clock (step S316), then the
value of the variable S is added to the value of the variable cnt
(step S318), and further 1 is added to the value of the variable k
(step S320).
[0335] Since in the example shown in FIG. 15, P4 is set to be "0
[V]," and P3 is set to be "3[V]," the amount S of increase and
decrease of the counter becomes "(-3/N) [V]," and the value of the
variable cnt decreases by "(3/N) [V]" from 3[V] every time the
value of the variable k increases by 1. Therefore, the counter 33
outputs the signal waveform, which decreases by "(3/N) [V]" from
the previous value every time the value of the variable k increases
by "1," to the amplifier 35.
[0336] Subsequently, when the value of the variable k exceeds the
value of the variable N (the branch of "No" in the step S314),
since the next nodal point data does not exist here (the branch of
"No" in the step S322), the process proceeds to the original
process, and if a halt command or a termination command is
provided, the drive signal supply process is halted or terminated.
On the other hand, if neither the halt command nor the termination
command is provided, the process from the step S300 is executed
again with respect to the waveform information thus set. Thus, the
signal waveform of the same waveform information can continuously
be output.
[0337] It should be noted that the operation of the fluid jet
emitting section 2 after supplying the piezoelectric element 401
with the drive signal is substantially the same as the operation of
the first embodiment described above, and therefore, the
explanations therefor will be omitted.
[0338] As explained hereinabove, if the nodal point data of the
trapezoidal wave is stored in the data storage section 30c, the
fluid jet device 1 of the present embodiment can supply the
piezoelectric element 401 of the pulsation generation section 100
with the drive signal composed of the analog trapezoidal signal
waveform while interpolating the data between the nodal points
using the nodal point data.
[0339] Thus, since the data capacity of the waveform information
can significantly be reduced in comparison with the case of the
sine waves, the memory device with a large capacity is not
required, and the fluid jet device can be configured with
relatively low cost.
[0340] Further, since it is arranged that the signal waveform
output process is executed using the algorithms shown in the flow
charts of the steps S208 through S220 described above and the steps
S300 through S324 described above, even if the drive signal supply
command and the drive signal halt command are input at any timing,
it is possible to supply the piezoelectric element 401 with the
drive signal so as to always start with the head of the waveform
and end with the tail thereof.
[0341] Thus, since it does not occur that the drive signal is
supplied to the piezoelectric element 401 from the middle of the
waveform or that the drive signal is suddenly switched to a no
signal state in the middle of the supply of the drive signal, the
piezoelectric element 401 can be prevented from being damaged by,
for example, suddenly shrinking the piezoelectric element 401.
[0342] It should be noted that although in the first embodiment the
configuration capable of generating the waveform information with
an appropriate signal waveform in accordance with the measurement
values of P.sub.gen and P.sub.sup of the fluid jet emitting section
2 is explained, the configuration is not limited thereto, but can
be a configuration of previously generating the waveform
information of the signal waveform corresponding to the values of
P.sub.gen and P.sub.sup, and holding the waveform information.
According to this configuration, although the drive section 30
becomes only available for the fluid jet emitting section 2 of the
same pressure specification, since the pressure sensor, the signal
waveform generation section 30b, and so on become unnecessary to be
provided, the corresponding cost (the cost of the sensor, the cost
of writing the program, and so on) can be reduced. Further, as
another embodiment, it is also possible to adopt a configuration in
which the values of P.sub.gen and P.sub.sup measured previously
prior to the shipment are stored in the fluid jet emitting section
2 (e.g., by adding a memory device storing the values), and the
values of P.sub.gen and P.sub.sup are obtained when replacing the
fluid jet emitting section 2 or powering on to generate the
waveform information of the signal waveform corresponding to the
values of P.sub.gen and P.sub.sup. According to this configuration,
since it can cope with a plurality of types of pressure
specifications, and need for providing the pressure sensor for
measuring P.sub.gen and P.sub.sup is eliminated, the cost can be
reduced accordingly.
[0343] Further, although the first through third embodiments
described above, which are preferable specific examples of the
invention, are provided with various technically preferable
limitations, the scope of the invention is not limited to these
embodiments unless the description to limit the invention thereto
is particularly presented in the explanations described above.
Further, the drawings used in the explanations described above are
schematic diagrams having contraction scales in the vertical and
horizontal directions of the members or parts different from the
actual scales for the sake of convenience of illustration.
[0344] Further, the invention is not limited to the first through
third embodiments described above but includes modifications and
improvements within a range where the advantages of the invention
can be achieved.
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