JP3352154B2 - Optical element drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element driving device for driving an optical element constituting a zoom, iris and focus mechanism of a camera or an endoscope.

[0002]

2. Description of the Related Art As a conventional example of an optical element driving device for driving an optical element constituting a zoom, iris, and focus mechanism of a camera or an endoscope, a piezoelectric element is disclosed in, for example, Japanese Patent Application Laid-Open No. 4-69070. Is fixed to a part of the optical device body, the vibration axis attached to the other part of the piezoelectric element and the optical element are frictionally engaged, and the piezoelectric element generates an impact force and vibrates with the optical element. Some have caused the shaft to slide and drive the optical element.

Further, as disclosed in Japanese Patent Application Laid-Open No. 4-69071, an optical element is fixed to a part of a piezoelectric element, and a weight is fixed to another part of the piezoelectric element. In some cases, an impact force is also generated by a piezoelectric element in a state where the optical element is frictionally engaged with the optical element, causing a slip between the optical element and the optical device main body to drive the optical element.

[0004]

In the conventional apparatus, the vibration axis is frictionally engaged with the optical element to transmit the impact force of the piezoelectric element to the optical element, or the optical element is directly attached to the piezoelectric element. When the optical element is tilted from its original state in the optical device, it is tilted up to the piezoelectric element, and the characteristics of the driving device may change significantly. In the worst case, the force of the piezoelectric element works to bite the optical element into the optical device, and the function of the driving device may be lost at all.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and even if an optical element is tilted from a direction in which it should move, a force component due to the tilt is absorbed so that the tilt is not transmitted to the moving body, and the impact force is reduced. To provide an optical element driving device in which the frictional force applied to the moving body driven by the optical element does not change, and as a result, the impact force applying means does not tilt, and the driving characteristics due to the impact force do not change. And

[0006]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
The optical element driving device of the present invention has piezoelectric or electrostrictive characteristics.
Optical element using the impact force due to the expansion and contraction of the piezoelectric / electrostrictive element
A predetermined optical element
A base that holds the base so that it can move back and forth,
And receives a predetermined impact force to resist the frictional engagement.
A movable body that can move forward and backward, and the predetermined
Impact applying hand fixed to the moving body for applying an impact
A step, for connecting the moving body and the optical element,
An optical element-side connecting means provided on the optical element,
It is connected to the optical element side connecting means with a predetermined gap.
Moving body side connecting means provided on the moving body.
It is characterized by doing.

[0007]

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIGS. 1 to 3 relate to a first embodiment of the present invention. FIG. 1 shows a focus drive mechanism portion of the first embodiment provided at a distal end portion of an endoscope, and FIG. 2 shows a signal processing system of the focus drive mechanism. FIG. 3 shows the waveform of the drive signal.

FIG. 1 shows a focus driving mechanism portion of a first embodiment in an image pickup apparatus 1 at the distal end of an endoscope. In this imaging apparatus 1, a focus lens 4 is mounted via a movable lens frame 5 to a lens barrel 3 housed in a hollow portion of a distal end main body 2 on the distal end side of an insertion section. On the rear side, a CCD 6 is fixed to the lens barrel 3 via a CCD fixing frame 7.

The movable lens frame 5 extends through a notch 8 provided in the lens barrel 3 and extends in a direction orthogonal to the optical axis direction.
The end of the arm 9 is housed in, for example, a cylindrical hollow portion, and is engaged with the focus actuator. That is, the end of the arm 9 is attached to the moving body 12 attached to the piezoelectric element 11, and the pin 1 has an H-shaped cross section.
3 is engaged.

A piezoelectric element 11 formed of a piezoelectric crystal having piezoelectric characteristics such as quartz crystal or Rochelle salt is applied with a drive signal to an electrode attached to the piezoelectric element 11 via a signal line 14 so that the piezoelectric element 11 can be moved in the front-rear direction. (The direction parallel to the optical axis).

The movable body 12 attached to the tip of the piezoelectric element 11 is provided with a cylindrical beam 15, and the distal end of the beam 15 is frictionally engaged with the lens barrel 3 and the wall surface of the tip body 2. . A moving body 12 is attached to the front end of the piezoelectric element 11 and the rear end side is a free end. Therefore, when the piezoelectric element 11 is rapidly expanded or contracted, the moving body 12 is moved in accordance with the expansion or contraction of the piezoelectric element 11. So that they can be moved. Since the movable body 12 is connected to the movable lens frame 5 via the pins 13 and the arms 9, the movable lens frame 5 and the focus lens 4 move with the movement of the movable body 12.

When the piezoelectric element 11 is slowly expanded or contracted, the moving body 12 is held in a state where it is not moved by the frictional engagement of the end portion of the beam 15 with the wall surface, and the piezoelectric element 11 is slowly moved. And can be expanded or contracted.

A linear encoder 17 fixed to the wall of the distal end body 2 is connected to the distal end of the beam 15 via a moving element 16 so as to detect the movement of the distal end of the beam 15. .

In this embodiment, the step-like small-diameter portion 18 of the pin 13 is engaged in the hole at the end of the arm 9 with a slight gap, so that the arm 9 and the pin 13 are engaged. As shown in FIG. 1, the width (length) of the small-diameter portion 18 in the optical axis direction is longer than the width of the end of the arm 9, and a small gap Δ (for example, Δ = 0, about 05 mm) is formed. When the arm 9 or the movable lens frame 5 is slightly tilted (from the direction in which it should be moved), the force component due to the tilt is not transmitted to the moving body 12 via the pin 13. The contact portion with the cylinder 3 absorbs the force.

That is, a gap Δ is provided at the connecting portion between the pin 13 and the arm 9 forming the transmission mechanism for transmitting the driving force from the piezoelectric element 11 to the movable lens frame 5, and even if the movable lens frame 5 side is inclined, Due to the gap Δ, a force component due to the inclination is not transmitted to the pin 13 or the moving body 12 side.

Therefore, in this case, the inclination is
Therefore, the frictional force (at the end portion of the beam 15) does not change. The force component that is not transmitted is absorbed by the contact portion between the lens frame 5 and the lens barrel 3. In this case, the movable body 12 moves and the stepped portion (dish) on both sides of the small diameter portion 18 of the pin 13 pushes the distal end of the arm 9, so that the movable lens frame 5 is parallel to the optical axis of the focus lens 4. Move in different directions.

FIG. 2 shows a configuration of a driving mechanism of the piezoelectric element 11. The output signal of the CCD 6 is input to a video signal processing circuit 21, where a video signal is generated and output to a monitor (not shown). The luminance signal component of the video signal is input to the piezoelectric element control circuit 22. The movement information detected by the linear encoder 17 is also input to the piezoelectric element control circuit 22.

The piezoelectric element control circuit 22 extracts a high-frequency component of the spatial frequency from the luminance signal component, and determines whether or not a focus state has occurred. If not in the focus state, the piezoelectric element 11
Is applied to the piezoelectric element 11. When the focus state is set, the output of the drive signal is stopped.

Next, the operation will be described. FIG. 3 shows the piezoelectric element 11.
When a voltage pulse as shown in (a) or (b) is applied as a drive signal, an impact force is applied to the moving body 12 by the piezoelectric element 11, and the moving body 12 slides slightly with respect to the lens barrel 3.
When the voltage pulse is continuously applied, the moving body 12 can be moved over a long distance.

The arm 4 of the lens frame 5 is a pin 1
When the moving body 12 is moved by being pushed by the plate portion of No. 3, the moving body 12 moves. At this time, as shown in FIG. 2, the application of the voltage pulse to the piezoelectric element 11 is controlled based on the video information from the CCD 6 and the position information of the moving body 12 from the linear encoder 17, and the focus state can be automatically set. Note that the present invention is not limited to focus, and can be applied to zoom.

The effect of this embodiment is as follows. Since the arm 9 of the lens frame 4 is very loosely engaged with the pin 13, the piezoelectric element 11 does not tilt even if the lens frame 5 tilts. Therefore, the performance of the actuator acting as the focus driving mechanism does not change.

FIG. 4 shows an image pickup apparatus 31 according to a second embodiment of the present invention.
Is shown. As in the first embodiment, the lens barrel 3 is attached to the distal end body 2.
Is stored, and the focus lens 4 is attached to the lens barrel 3 via the lens frame 5.
The CD 6 is fixed via the CCD frame 7. The lens frame 5 has an arm 32 penetrating through the notch 8 of the lens barrel 3 and is connected to a focus actuator housed in a focus actuator housing section (hereinafter referred to as a housing section) 33.

A first piezoelectric element 34 is accommodated in the accommodating portion 33, and the rear end of the piezoelectric element 34 is adhesively fixed to a mount 35, and the mount 35 is fixed to the lens barrel 3.
An L-shaped member 36 formed in an L-shape is attached to the tip of the piezoelectric element 34.

The L-shaped member 36 includes a first piezoelectric element 3
A plate-like elastic body 37 is attached to a surface parallel to the expansion and contraction direction (direction parallel to the optical axis) of 4, and a pressing member 38 extending in a direction perpendicular to the optical axis direction is attached to the elastic body 37. Have been. The pressing member 38 is pressed into the circular tube 39 together with the L-shaped member 36, and the circular tube 39 is frictionally engaged with the L-shaped member 36 and the pressing member 38. L-shaped member 36
The second piezoelectric element 41 is attached to a surface perpendicular to the direction of expansion and contraction of the piezoelectric element 34 and the pressing member 38.

Due to the expansion and contraction of the piezoelectric element 41, the pressing member 38
Can be tilted in the moving direction of the lens 4 in the circular tube 39. The distal end of the circular tube 39 is in contact with the arm 32 of the lens frame 5. One end of a spring 42 is in contact with the opposite surface of the circular tube 39 across the arm 32 of the lens frame 5, and the other end of the spring 18 is fixed to the lens barrel 3.

Next, the operation will be described. DC to piezoelectric element 41
When a voltage is applied, the pressing member 38 is inclined by, for example, θ in the traveling direction of the lens 4, and f (force applied between the pressing member 38 and the circular tube 39 before tilting the pressing member 38) is applied to the circular tube 39.
The force of x sin θ is applied in the traveling direction of the lens 4, and the circular tube 39 becomes slippery in the direction in which the force of f sin θ is applied, but hardly slips in the opposite direction.

When a square wave pulse is applied to the piezoelectric element 34 in this state, an impact force is applied to the L-shaped member 36 from the piezoelectric element 34, and the L-shaped member 36 and the pressing member 38
However, since the slippage is given a polarity by the inclination of the press-contact member 38, the circular tube 39 slides on only one side as a whole.

If square wave pulses are continuously applied, the circular tube 3
9 can move a long distance. As a result, lens 4
Is moved on the optical axis by being pushed by the circular tube 39 and the spring 42, and focusing is performed.

In this embodiment, the arm 32 is held in a state where it is urged in a direction parallel to the optical axis by the spring 42 whose one end is in contact. The tilting force is suppressed.

The present invention can be applied to a zoom mechanism instead of the focus drive mechanism. It is also conceivable to use the actuator of the second embodiment to drive the forceps raising table, bend the treatment tool, and open and close the forceps.

Next, a third embodiment of the present invention will be described. FIG.
Denotes an external camera 52 attached to the endoscope eyepiece 51, and the aperture device 54 of the third embodiment is provided in front of the objective lens system 53 of the external camera 52. An optical filter 55 and a CCD 56 are mounted behind the objective lens system 53.

FIG. 6 shows the structure of the diaphragm device 54. The aperture device 54 has the following configuration. Squeeze hole 60 in the center
A rotating plate 61 rotatable with respect to the main body of the external camera 52, an aperture blade 62 (only one is shown) rotatably attached to the rotating plate 61,
A collision element 63 which is also rotatably mounted on the opposite surface of the diaphragm blade 62 with the rotation plate 61 interposed therebetween and has a small gap with the rotation plate 61, and a collision element 6 mounted on the rotation plate 61
The projections 64 and 6 which collide with the rotation plate 3 and apply a rotational force to the rotating plate 61.
4, a vibration shaft 65 that press-fits into the arc-shaped groove 63a of the collision element 63 and frictionally engages with the collision element 63 to apply the impact force of the piezoelectric element 66 to the collision element 63, and fixes the vibration axis 65 and one end in the direction of expansion and contraction thereof. The other end includes a piezoelectric element 66 having one end fixed to the external camera 52 and an encoder 67 provided on a side of the rotating plate 61.

The diaphragm blade 62 is fixed to a rotating plate 61 by a stop pin 68.
The camera is rotatably fixed by a driving pin 69 fixed to the external camera 52 so as to be rotatable. The rotating plate 61 has a slight frictional engagement with the external camera 52.

Next, the operation will be described. FIG. 3 shows the piezoelectric element 66.
When the voltage pulse as shown in (1) is applied, the vibration shaft 65 and the collider 63 slide and the collider 63 rotates and collides with one of the protrusions 64. Then, the rotating plate 61 receives a rotational force from the projection 64 and rotates.

As a result, since the drive pin 69 is stopped, the diaphragm blade 62 receives the rotational force and rotates around the stopper pin 68 to open and close the diaphragm hole 60. Also, in this embodiment, the aperture adjustment is automatically performed by providing a control system as shown in FIG.

The effects of this embodiment are as follows. Since there is a gap between the member transmitting the force of the piezoelectric element to the optical element and the optical element and the optical element is tilted in the optical device, the piezoelectric element does not tilt, so that the characteristics of the driving device do not change significantly.

It should be noted that a similar aperture mechanism can be realized by directly frictionally engaging the vibration shaft 65 with the rotary plate 61. A similar aperture mechanism can be realized even if the vibration shaft 65 is a magnet.

Next, a fourth embodiment of the present invention will be described with reference to FIG. This embodiment relates to a diaphragm mechanism as in the third embodiment. Therefore, only portions different from the third embodiment are shown.

A mounting base 72 is provided on the collision element 71 in this embodiment, and a piezoelectric element 73 is fixed at one end in the expansion and contraction direction. A friction member 74 is attached to the other end of the piezoelectric element 73, and the friction member 74 is frictionally engaged with the external camera 52.

Next, the operation will be described. FIG. 3 shows the piezoelectric element 73.
Is applied to the friction member 74, the impact force due to the inertial force of the collision element 71 is applied to the friction member 74.
4 slides with respect to the external camera 52, and the collision element 71 rotates. When a pulse is continuously applied, the impactor 71 hits the projection 64 and the rotary plate 61 rotates, and the aperture hole 60 changes the light shielding area by the aperture blade 62 to open and close the aperture.

The effect of this embodiment is as follows. Since there is a gap between the optical element and the member that transmits the force of the piezoelectric element to the optical element, and the piezoelectric element does not tilt even if the optical element is tilted in the optical device, the characteristics of the driving device do not greatly change.

Next, a fifth embodiment of the present invention will be described with reference to FIG. Only different points from the third embodiment are shown. One end of the bimorph element 75 is fixed to the external camera 52. The base end of the vibration shaft 77 is fixed to the other end of the bimorph element 75. The tip of the vibration shaft 77 is frictionally engaged with the collision element 78 by press fitting. The bending direction of the bimorph element 75 is the same as the rotation direction of the rotating plate 61.

Next, the operation will be described. Bimorph element 75
When a voltage pulse as shown in FIG.
7 is given an impact force, and the tip of the vibration shaft 77 is
Cause tangential slippage. When a pulse is continuously applied, the collision element 78 collides with the projection 64 and the rotating plate 61 rotates. As a result, the aperture blade opens and closes.

The effect of this embodiment is as follows. Since there is a gap between the member transmitting the force of the piezoelectric element to the optical element and the optical element, and the optical element is tilted in the optical device, the piezoelectric element does not tilt, so that the characteristics of the driving device do not greatly change.

In the above-described embodiment, a piezoelectric element having piezoelectric characteristics is used to generate a driving force. However, an electrostrictive element having electrostrictive characteristics may be used instead of the piezoelectric element. Further, a magnetostrictive element utilizing magnetostrictive characteristics may be used.

[0047]

As described above, according to the present invention, even when the optical element is tilted from the direction in which it is to be moved, the force component due to the tilt is absorbed so that the tilt is not transmitted to the moving body, and the impact force is reduced. The frictional force applied to the driven moving body does not change, and as a result, the impact force applying means does not tilt, and the driving characteristics due to the impact force do not change.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a focus driving mechanism according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a signal processing system of a focus driving mechanism.

FIG. 3 is a waveform chart showing a waveform of a driving signal.

FIG. 4 is a cross-sectional view illustrating a focus driving mechanism according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating an external camera provided with an aperture device according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a diaphragm device according to a third embodiment.

FIG. 7 is a diagram showing a diaphragm device according to a fourth embodiment of the present invention.

FIG. 8 is a diagram showing a diaphragm device according to a fifth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Imaging device 2 ... Tip part main body 3 ... Lens barrel 4 ... Focus lens 5 ... Lens frame 6 ... CCD 8 ... Notch 9 ... Arm 11 ... Piezoelectric element 12 ... Moving body 13 ... Pin 14 ... Signal line 15 ... Beam 16 … Motor 18… Narrow diameter part 21… Video signal processing circuit 22… Piezoelectric element control circuit

Claims (1)

(57) [Claims] 1. A piezoelectric / electrostrictive element having piezoelectric or electrostrictive characteristics.
Optical element that drives optical elements using the impact force of
In the elementary drive device, a base that holds a predetermined optical element so as to be able to move forward and backward is frictionally coupled to the base and receives a predetermined impact force.
A movable body that can move forward and backward against the frictional engagement, and the predetermined impact is applied to the movable body.
Shock applying means fixed to a moving body, and the light for connecting the moving body and the optical element;
Optical element side connecting means provided on the optical element, and connecting the optical element side connecting means by providing a predetermined gap
And a moving body side connecting means provided on the moving body .