JP2004007913A - Optical instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical instrument having an electromechanical transducing element capable of being used for lens driving and a buzzer. <P>SOLUTION: A voltage which permits the electromechanical transducing element to be used for lens driving and the buzzer and changes in different frequencies from each other, is applied to the electromechanical transducing element. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical apparatus using an electromechanical conversion element for moving an optical axis member.
[0002]
[Prior art]
Conventionally, in an optical device such as a camera or a video camera having an autofocus function and a power zoom function, distance information indicating a distance to a subject, contrast information of a subject image formed on a solid-state image sensor, a zoom lever The focus lens and the zoom lens are moved to the target position on the optical axis based on the operation amount for.
[0003]
Recently, in these optical devices, an electro-mechanical conversion element has begun to be used instead of a motor for moving the lens.
[0004]
This electro-mechanical conversion element is an element whose thickness changes in accordance with an applied drive voltage. Japanese Patent Laid-Open No. 9-191676 discloses that this electro-mechanical conversion element is used for moving the lens. Proposed.
[0005]
If an electro-mechanical conversion element is used for the lens moving mechanism, the optical device can be miniaturized because the structure is simpler than when a motor is used.
[0006]
Japanese Patent Laid-Open No. 58-58532 proposes the use of an electromechanical conversion element as a buzzer.
[0007]
[Problems to be solved by the invention]
Recently, optical devices such as cameras are required to be multi-functional as well as miniaturized.
[0008]
Therefore, it can be considered that the electromechanical conversion element employed in the optical apparatus is also used as a buzzer as described above.
[0009]
Here, in order to drive the electro-mechanical conversion element, a drive signal that changes at a predetermined frequency is applied to the electro-mechanical conversion element, but even if the electro-mechanical conversion element for driving the lens is used as a buzzer The appropriate frequency for driving the lens is in the ultrasonic band, so it cannot be used as a buzzer. On the other hand, even if an electromechanical conversion element for a buzzer is used for driving a lens, the audible frequency band is used. There is a problem that the lens cannot be driven properly at a frequency of.
[0010]
In view of the above circumstances, an object of the present invention is to provide an optical apparatus that can use the provided electro-mechanical conversion element for both driving of a lens and a buzzer.
[0011]
[Means for Solving the Problems]
To achieve the above object, an optical apparatus of the present invention is an optical apparatus including an optical member that receives a driving force and moves in a predetermined movement direction.
A holding member for holding the optical member;
An electro-mechanical conversion element whose thickness changes according to a driving voltage as a driving source for generating a driving force applied to the holding member;
A drive rod extending in the moving direction and acting on the movement of the holding member in the moving direction by transmitting the change in thickness of the electromechanical conversion element to the holding member;
A buzzer mode in which sound is generated in the electro-mechanical conversion element by giving a drive signal having a frequency within the audible frequency band to the electro-mechanical conversion element, and driving of the electro-mechanical conversion element at a frequency exceeding the audible frequency band. The optical apparatus according to the present invention includes an element driving unit having a driving mode for driving the optical member to the electro-mechanical conversion element by giving a signal. When the element is used in the drive mode and when used in the buzzer mode, a drive voltage that changes at a frequency corresponding to each is applied. Thus, according to the optical apparatus of the present invention, the electromechanical conversion element can be used for both driving of the lens and the buzzer.
[0012]
Here, it is preferable that the holding member be a member that can avoid driving depending on a driving signal having a frequency within an audible frequency band.
[0013]
In the lens driving device of the present invention, when the electromechanical conversion element is used as a buzzer, even if the lens is moved due to an unexpected state such as resonance, the lens is returned to the origin to cope with it. In this way, such initialization operation can be omitted.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0015]
FIG. 1 is a front view of an embodiment of the optical apparatus of the present invention.
[0016]
A camera 1 according to this embodiment shown in FIG. 1 is a digital camera equipped with a lens barrel and having an autofocus and power zoom function. However, the length of this lens barrel is unchanged even during focusing and zooming.
[0017]
On the front surface of the camera 1 shown in FIG. 1, a lens barrel 12 containing a front lens 11 is near the center, a flash emission window 15 is above the lens barrel 12, and a finder objective window 13 a is the flash emission window 15. A release button 14 is provided on the left (right in FIG. 1) and on the upper right end (upper left end in FIG. 1). The release button 14 is of a two-stage type, and can be locked in focus when it is half-pressed.
[0018]
FIG. 2 is a rear view of the camera shown in FIG.
[0019]
On the back side of the camera 1 shown in FIG. 2, the liquid crystal panel 18 is slightly near the center, the mesh 20 is on the right side of the liquid crystal panel, the zoom switch 19 is above the mesh 20, the function switch 17a and the shooting mode switch 17b. Above the liquid crystal panel 18, a viewfinder eyepiece window 13b is provided at the upper left corner.
[0020]
The camera 1 has two functions of a “photographing and recording” function and an “image data reproduction” function, and one of the functions is selected by the function switch 17a. Further, the “shooting and recording” function includes a “portrait shooting” mode, a “sport shooting” mode, and a “landscape shooting” mode, and any one of these modes is selected by the shooting mode switch 17b. The zoom switch 19 is zoomed to the telephoto side by operating the upward triangular portion, and is zoomed to the wide angle side by operating the downward triangular portion.
[0021]
FIG. 3 is an internal configuration diagram of the camera shown in FIGS. 1 and 2. In FIG. 3, the AF arithmetic circuit, the focus lens drive mechanism, the encoder for detecting the absolute position of the lens in the lens barrel, and the flash mechanism are not shown.
[0022]
FIG. 3 also shows a lens driving mechanism 100 employed in the camera 1 of the present embodiment. This lens driving mechanism 100 includes a piezoelectric element drive including a drive shaft piezoelectric element 142 that expands and contracts in the optical axis direction. The driving shaft 130 is joined to the end portion of the driving shaft piezoelectric element 142, and the driving portion 110. Note that the left side of FIG. 3 is the front direction of the camera, and the solid-state imaging device 22 is also shown behind the drive unit 110. The end of the drive shaft piezoelectric element 130 opposite to the end where the drive shaft is joined is fixed to the camera body 21.
[0023]
The piezoelectric element driving unit 140 includes a base 141, a drive shaft piezoelectric element 142, a drive shaft piezoelectric element driver 143, and a power supply 144. The base 141 is fixed to the camera body 21 and is a drive shaft piezoelectric element. Element 142 is attached. Two electric lines are shown from the drive shaft piezoelectric element 142, and one is a line for receiving power supply from the power supply 144 via the drive shaft piezoelectric element driver 143. Is a ground wire.
[0024]
The drive unit 110 includes a zoom lens group 112 and a zoom lens holding frame 111 that holds the zoom lens group 112.
[0025]
In this lens driving mechanism 100, the end of the zoom lens holding frame 111 is penetrated by the driving shaft 130, and the zoom lens holding frame 111 is coupled to the driving shaft 130 with a predetermined frictional force. . Whether the lens holding frame coupled to the drive shaft with a predetermined frictional force moves in the optical axis direction according to the degree of acceleration generated in the drive shaft as the drive shaft piezoelectric element 130 expands and contracts. Determined. A similar lens movement is also performed in a lens driving mechanism for a focus lens (not shown).
[0026]
Here, the above movement will be briefly described.
[0027]
First, the case where the drive part 110 shown by FIG. 3 is moved to the camera front side is demonstrated. In the following, the principle proposed in Japanese Patent Laid-Open No. 9-191676 will be described.
[0028]
FIG. 4 is a diagram illustrating the principle of driving the camera forward.
[0029]
FIG. 5 is a diagram showing a change in voltage applied to the drive shaft piezoelectric element in this case.
[0030]
FIG. 5 shows a change in the applied voltage that gradually increases and rapidly decreases after a predetermined voltage is reached.
[0031]
When a voltage that changes as shown in FIG. 5 is applied to the drive shaft piezoelectric element 142, the thickness of the drive shaft piezoelectric element 142 from the state shown in FIG. The thickness gradually increases and the state shown in FIG. For this reason, the drive shaft 130 is pushed by the piezoelectric element 142 and moves in the forward direction of the camera (left side in FIG. 4). Then, as shown in FIG. 4B, the drive unit 110 placed in a driven state with respect to the drive shaft moves the drive shaft 130 in the forward direction of the camera (left direction in FIG. 4) at a considerably slow speed. Therefore, it moves in the forward direction of the camera without slipping with respect to the drive shaft 130.
[0032]
However, after this applied voltage reaches the value V1, it suddenly decreases to a value of 0 after a while, so that the thickness of the piezoelectric element 142 is rapidly reduced. Then, the drive shaft 130 also moves rightward in FIG. 4 at a stretch as shown in FIG. Due to this sudden movement of the drive shaft 130, the drive unit 110 remains at the position shown in FIG. 4B before the drive shaft 130 suddenly moves. This means that the camera has advanced in the front direction of the camera by the indicated distance x.
[0033]
Next, the case where this drive part 110 is moved to the camera back side is demonstrated.
[0034]
FIG. 6 is a diagram showing the principle of driving to the rear side of the camera.
[0035]
In this case, the applied voltage to the drive shaft piezoelectric element 142 may have a change as shown in FIG.
[0036]
FIG. 7 is a graph showing a change in voltage applied to the drive shaft piezoelectric element when the drive unit is moved to the back side of the camera.
[0037]
FIG. 7 shows how the applied voltage increases rapidly and then decreases gently.
[0038]
In this case, the piezoelectric element 142 in the state shown in FIG. 6A is supplied with the drive voltage of the sudden rise shown in FIG. 7, and suddenly moves in the forward direction of the camera (left side in FIG. 6). Elongate. As a result, the drive shaft 130 also suddenly moves in the forward direction of the camera, so that the drive unit 110 slides on the drive shaft 130 in the rear direction of the camera as shown in FIG. 6B. Thereafter, as the driving voltage is gradually reduced, the piezoelectric element 142 is slowly contracted in the rear direction of the camera (on the right side in FIG. 6), as shown in FIG. 6C. Move in the direction. Since the operation of the drive shaft 130 is slow, the drive unit 110 also moves to the rear side of the camera together with the drive shaft without sliding with respect to the drive shaft. As a result, the drive unit 110 has moved by the distance Y toward the back side of the camera.
[0039]
Here, returning to the description of FIG. 3 again, FIG. 3 also shows the release switch 14 and various switches, the power switch 16, and the CPU 10 for controlling the entire camera 1. Is transmitted to the CPU 10.
[0040]
In this camera 1, the drive shaft piezoelectric element 142 shown in FIG. 3 can also be used as a buzzer. When the power switch 13 shown in FIG. The sound 'can be heard through the mesh 20 shown in FIG. Hereinafter, the features of the present invention will be described while describing the photographing operation of the camera 1 of the present embodiment.
[0041]
When the power switch 16 shown in FIG. 3 is turned on, a signal indicating an on operation for the power switch is transmitted to the CPU 10. Upon receiving this signal, the CPU 10 sends the drive shaft piezoelectric element 142 to the drive shaft piezoelectric element 142. Instructs the application of a voltage that changes at a frequency of 4 kilohertz so as to pronounce “beep” indicating power-on. As a result, the drive shaft piezoelectric element 142 produces a “beep”.
[0042]
Thereafter, when the subject is caught within the angle of view and the zoom switch 19 shown in FIG. 2 is operated, the zoom lens group (not shown) is driven by the power zoom function in accordance with the operation. The zoom lens group is driven by applying a voltage varying at a frequency of 150 kilohertz to the piezoelectric element for the drive shaft. After that, when aiming at the subject and pressing the release button halfway, the autofocus function moves the focus lens group in the optical axis direction to perform focusing. This focusing is also performed by applying a voltage having a frequency of 150 kilohertz to the drive shaft piezoelectric element 142 in the same manner as the zooming. When this focusing is completed, a voltage changing at a frequency of 4 kilohertz is applied to the drive shaft piezoelectric element 142 and a “pit” representing the in-focus state is generated.
[0043]
When focusing is completed in this way, shooting is performed by fully pressing the release button 14. In this camera, image data representing an image displayed on the liquid crystal panel 18 is recorded in a memory (not shown) at the time of full pressing, and a voltage changing at a frequency of 4 kilohertz is applied to the drive shaft piezoelectric element 142. 'Pip' is pronounced.
[0044]
Thus, in the camera 1 of the present embodiment, the drive shaft piezoelectric element is also used for the sound of a “beep” in addition to the use for moving the focus lens and the like.
[0045]
FIG. 8 is a flowchart of a routine that is started when the power switch shown in FIG. 3 is turned on.
[0046]
In step S1 of FIG. 8, it is determined whether or not the lens needs to be moved, and it is determined whether or not the zoom lens and the focus lens need to be moved by half-pressing the zoom lever and the release switch. This is determined based on information from an AF circuit and an encoder (not shown). If it is determined in step S1 that the lens needs to be moved, the drive shaft piezoelectric element driver is instructed to drive the drive shaft piezoelectric element at a frequency of 150 kilohertz, which is the lens moving frequency. Is issued. Then, it returns to step S1. If it is determined in step S1 that it is not necessary to move the lens, the process proceeds to step S3, where it is determined whether or not buzzer sound is necessary. This is determined by whether a signal indicating on / off of the power switch has been transmitted or a signal indicating in-focus has been transmitted. If it is determined in step S3 that sound generation of the buzzer is necessary, the process proceeds to step S4, and the drive shaft piezoelectric element driver is driven so as to drive the drive shaft piezoelectric element at a frequency of 4 kilohertz which is the sound generation frequency. Is instructed. In addition, even if an abnormal state such as resonance occurs when a voltage that changes the frequency of the piezoelectric element for the drive shaft is generated between the drive shaft and the zoom lens holding frame of the present embodiment, A sufficient frictional force is working to keep the position of the lens holding frame relative to the drive shaft. Then, it returns to step S1.
[0047]
In the above-described embodiment, the digital camera has been described as an example. However, the piezoelectric element, which is an example of the electro-mechanical conversion element, is switched between the lens frequency and the buzzer by switching the frequency of the voltage applied to the piezoelectric element. However, the present invention is not limited to this, and a film on a roll may be taken as an example, and a video camera may be taken as an example.
[0048]
In this embodiment, the lens holding frame is coupled to the drive shaft with a predetermined frictional force, and the drive shaft is driven with a predetermined acceleration by driving the piezoelectric element. However, the present invention is not limited to this as long as the movement of the lens is performed by causing the drive shaft to act on the drive rod, which is an example. The driving direction of the electromechanical conversion element may not be the same as the moving direction of the lens. Further, in the present embodiment, the example in which the lens holding frame is fixed to the drive rod when using the piezoelectric element as a buzzer has been described. However, even if this is not performed, the effect of the present invention is achieved. Is not something to lose.
[0049]
【The invention's effect】
As described above, according to the optical apparatus of the present invention, the electromechanical conversion element can be used both for driving the lens and for the buzzer.
[Brief description of the drawings]
FIG. 1 is a front view of an optical apparatus according to an embodiment of the present invention.
FIG. 2 is a rear view of the camera shown in FIG.
3 is an internal configuration diagram of the camera shown in FIGS. 1 and 2. FIG.
FIG. 4 is a diagram illustrating a driving principle toward the front side of a camera.
FIG. 5 is a diagram showing a change in voltage applied to a piezoelectric element for a drive shaft.
FIG. 6 is a diagram showing the principle of driving to the back side of the camera.
FIG. 7 is a graph showing a change in voltage applied to a drive shaft piezoelectric element.
FIG. 8 is a flowchart of a routine that is started when the power switch shown in FIG. 3 is turned on;
[Explanation of symbols]
1 Camera 10 CPU
DESCRIPTION OF SYMBOLS 11 Front lens 12 Lens barrel 13a Finder objective window 13b Finder eyepiece window 14 Release button 15 Flash light emission window 16 Power switch 17a Function switch 17b Mode switch 18 Liquid crystal panel 19 Zoom switch 20 Mesh 21 Camera body 22 Solid-state image sensor 100 Lens drive mechanism 110 Drive unit 111 Focus lens holding frame 112 Focus lens group 130 Drive shaft 140 Piezoelectric element drive unit 141 Base 142 Drive shaft piezoelectric element 143 Drive shaft piezoelectric element driver 144 Power supply

Claims (2)

In an optical apparatus including an optical member that receives a driving force and moves in a predetermined movement direction,
A holding member for holding the optical member;
An electro-mechanical conversion element whose thickness changes according to a driving voltage as a driving source for generating a driving force applied to the holding member;
A driving rod that extends in the moving direction and acts on movement of the holding member in the moving direction by transmitting a change in thickness of the electromechanical conversion element to the holding member;
A buzzer mode for generating a sound in the electro-mechanical conversion element by giving a drive signal having a frequency within an audible frequency band to the electro-mechanical conversion element, and driving the frequency exceeding the audible frequency band in the electro-mechanical conversion element An optical apparatus comprising: an element driving unit having a driving mode in which the electro-mechanical conversion element drives the optical member by applying a signal. 2. The optical apparatus according to claim 1, wherein the holding member is one that can be driven by a driving signal having a frequency within an audible frequency band.

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