1. A drive apparatus of a vibration-type actuator comprising:
an alternate current signal generation unit configured to generate a first alternate current signal applied to a first electrode of an electric-mechanical energy conversion element of a vibrator and a second alternate current signal applied to a second electrode of the electric-mechanical energy conversion element; and
a control unit configured to set a voltage amplitude of the first alternate current signal and a voltage amplitude of the second alternate current signal such that when the vibrator is in a non-movement state, the voltage amplitudes are set to be greater than 0 and to be in a dead zone,
wherein the dead zone is a range of the voltage amplitudes of the first alternate current signal and the second alternate current signal applied to the electric-mechanical energy conversion element, within which no driving force on a driven element is generated.
2. The drive apparatus of the vibration-type actuator according to claim 1, wherein the control unit is configured to control the first alternate current signal and the second alternate current signal such that a driven state of the vibrator and the non-movement state of the vibrator appear alternately.
3. The drive apparatus of the vibration-type actuator according to claim 1, wherein the alternate current signal generation unit includes a drive signal generation unit configured to generate pulse signals, and a voltage up-converter configured to generate the first alternate signal and the second alternate signal corresponding to the pulse signals.
4. The drive apparatus of the vibration-type actuator according to claim 3, wherein the control unit controls the voltage amplitudes of the first alternate signal and the second alternate signal by controlling pulse duty ratios of the pulse signals.
5. The drive apparatus of the vibration-type actuator according to claim 1, wherein the control unit sets the pulse duty ratio such that the pulse duty ratios of the pulse signals each are equal to an maximum value of the dead zone during a non-driven period of the vibration-type actuator.
6. The drive apparatus of the vibration-type actuator according to claim 1, wherein the control unit determines an ellipticity ratio of an elliptic motion occurring on the vibrator and determines a phase difference of the first and second alternate signals based on the ellipticity.
7. The drive apparatus of the vibration-type actuator according to claim 1, wherein the driven element is relatively moved by a combination of a first vibration mode that occurs on the vibrator when the first alternate current signal and the second alternate current signal are equal in phase and a second vibration mode that occurs on the vibrator when the first alternate current signal and the second alternate current signal are opposite in phase.
8. An interchangeable lens comprising:
a focus lens;
a vibration-type actuator configured to drive the focus lens; and
the driving apparatus configured to drive the vibration-type actuator according to claim 1.
9. An image pickup apparatus comprising:
a lens;
a vibration-type actuator configured to drive the lens;
the driving apparatus configured to drive the vibration-type actuator according to claim 1; and
an image sensor disposed on an optical axis of the lens.
10. The image pickup apparatus according to claim 9, wherein the non-movement state is one state of the vibrator in which the vibrator is when the lens is in focus.
11. A drive apparatus of a vibration-type actuator comprising:
an alternate current signal generation unit configured to generate a first alternate current signal applied to a first electrode of an electric-mechanical energy conversion element of a vibrator and a second alternate current signal applied to a second electrode of the electric-mechanical energy conversion element; and
a control unit configured to set a phase difference between the first alternate current signal and the second alternate current signal
such that when the vibrator is in a non-movement state, the phase difference is set to a value in a dead zone other than 0,
wherein the dead zone is a range of the phase difference between the first alternate current signal and the second alternate current signal applied to the electric-mechanical energy conversion element, within which no driving force on a driven element is generated.
12. The drive apparatus of the vibration-type actuator according to claim 11, wherein
the control unit is configured to set the phase difference to a particular value that is not equal to 0 and that is within the dead zone, and
wherein the particular value is set within a range between 0 and a selected one of a minimum value and a maximum value of the dead zone such that the selected one of the minimum value and the maximum value is closer, than the other one is, to a phase difference that occurs when driving is performed after the non-movement state.
13. The drive apparatus of the vibration-type actuator according to claim 11, wherein the control unit is configured to control the first alternate current signal and the second alternate current signal such that a driven state of the vibrator and the non-movement state of the vibrator appear alternately.
14. The drive apparatus of the vibration-type actuator according to claim 11, wherein the alternate current signal generation unit includes
a drive signal generation unit configured to generate pulse signals, and
a voltage up-converter configured to generate the first alternate signal and the second alternate signal corresponding to the pulse signals.
15. The drive apparatus of the vibration-type actuator according to claim 11, wherein the control unit sets the phase difference such that during a non-driving period in which the vibration-type actuator is not driven, the phase difference has a value equal to a minimum value or a maximum value of the dead zone depending on a moving direction.
16. The drive apparatus of the vibration-type actuator according to claim 11, wherein the control unit determines an ellipticity ratio of an elliptic motion occurring on the vibrator and determines a phase difference of the first and second alternate signals based on the ellipticity.
17. The drive apparatus of the vibration-type actuator according to claim 11, wherein the driven element is relatively moved by a combination of a first vibration mode that occurs on the vibrator when the first alternate current signal and the second alternate current signal are equal in phase and a second vibration mode that occurs on the vibrator when the first alternate current signal and the second alternate current signal are opposite in phase.
18. An interchangeable lens, comprising:
a focus lens;
a vibration-type actuator configured to drive the focus lens; and
the driving apparatus configured to drive the vibration-type actuator according to claim 11.
19. An image pickup apparatus comprising:
a lens,
a vibration-type actuator configured to drive the lens;
the driving apparatus configured to drive the vibration-type actuator according to claim 11; and
an image sensor disposed on an optical axis of the lens.
20. The image pickup apparatus according to claim 19, wherein the non-movement state is one state of the vibrator in which the vibrator is when the lens is in focus.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A lead insertion tool adapted for use with a lead introducer having an elastomeric hemostasis valve with a self-closing aperture, said tool comprising:
(a) a tubular sheath having a relatively thin wall at least one longitudinal groove formed inwardly thereof to facilitate rupture of the sheath along said groove and a lumen sized to receive a medical lead therethrough; and
(b) a tool dilator having a generally rigid shaft which when inserted through the lumen of the tubular sheath renders the sheath sufficiently rigid to allow insertion of the sheath and dilator through the self-closing aperture of the lead introducer.
2. The lead insertion tool as in claim 1 wherein the elastomeric hemostasis valve is contained in a plastic hub on a proximal end of said lead introducer and said plastic hub includes a side port located distal of the elastomeric hemostasis valve and the tubular sheath is of a length sufficient to pass through the self-closing aperture without blocking said side port.
3. The lead insertion tool as in claim 1 wherein said sheath includes a Luer fitting on a proximal end thereof.
4. The lead insertion tool as in claim 3 wherein the sheath includes a pair of wings extending generally perpendicularly from a longitudinal axis of the sheath to facilitate gripping and rupture of the sheath along said longitudinal groove and to serve as a stop preventing passage of the sheath fully beyond the hemostasis valve.
5. The lead insertion tool as in claim 3 wherein said tool dilator includes a Luer fitting for mating with the Luer fitting on the sheath.
6. The lead insertion tool as in any one of claims 1-5 wherein the shaft of the dilator is sized to substantially occlude the lumen of the tubular sheath.
7. The lead insertion tool as in claim 6 wherein the generally rigid shaft of the tool dilator includes a lumen adapted to receive a guidewire therethrough.
8. A lead insertion tool adapted for use with a lead introducer having an elastomeric hemostasis valve with a self-closing aperture formed therethrough, said tool comprising:
(a) a tubular sheath having a relatively thin wall with at least one longitudinally groove formed inwardly thereof to facilitate rupture of the sheath along said groove and a lumen sized to receive a lead body therethrough with a predetermined clearance fit, the tubular sheath being sufficiently rigid to be insertable through the self-closing aperture of the hemostasis valve.
9. The lead insertion tool of claim 8 wherein the elastomeric hemostasis valve is contained in a plastic hub on a proximal end of said lead introducer and said plastic hub includes a side port located distal of the elastomeric hemostasis valve and the tubular sheath is of a length sufficient to pass through the self-closing aperture without blocking said side port.
10. A method for facilitating insertion of a relatively limp medical lead through a self-closing aperture in an elastomeric hemostasis valve of a lead introducer comprising the steps of:
(a) providing a lead insertion tool having a tubular sheath with a wall defining a lumen, the wall having at least one longitudinal groove formed inwardly thereof to facilitate rupture of the sheath along said groove, said lumen sized to receive a lead body therethrough with a predetermined clearance fit, said tubular sheath being sufficiently rigid when surrounding a lead to allow insertion through the self-closing aperture of the hemostasis valve;
(b) inserting a distal end portion of a medical lead into the lumen of the tubular sheath;
(c) inserting the tubular sheath containing the distal end portion of the medical lead through the self-closing aperture of the elastomeric hemostasis valve;
(d) sliding the tubular sheath in a proximal direction along the lead body and out from the self-closing aperture leaving the lead body in place; and
(e) removing the tubular sheath by tearing same along the longitudinal wall.
11. A method for facilitating insertion of a relatively limp medical lead through a self-closing aperture in an elastomeric hemostasis valve of a lead introducer comprising the steps of:
(a) providing a lead insertion tool having a tubular sheath with a wall defining a lumen, the wall having at least one longitudinal groove formed inwardly thereof to facilitate rupture of the sheath along said groove, said lumen sized to receive a lead body therethrough with a predetermined clearance fit, said tubular sheath being sufficiently rigid when surrounding a lead to allow insertion through the self-closing aperture of the hemostasis valve;
(b) providing a tool dilator having a generally rigid shaft of a predetermined length and diameter;
(c) inserting the tool dilator into the lumen of the tubular sheath;
(d) passing the tubular sheath with the tool dilator through the self-closing aperture of the hemostasis valve;
(e) removing the tool dilator from the lead insertion tool; and
(f) inserting a distal end of the medical lead through the lumen of the lead insertion tool.
12. The method of claim 11 and further including the steps of:
(a) withdrawing the lead insertion tool from the self-closing aperture; and
(b) splitting the lead insertion tool along the longitudinal groove to remove the lead insertion tool from surrounding relation with respect to the medical lead.