JP2007033574A - Imaging device and lens drive control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens control device, etc., designed such that a displacement of a lens can be detected before photographing and that the position of the lens can be reset. <P>SOLUTION: The control section 108 of the lens control device discriminates whether a value corresponding to a voltage supplied from an acceleration sensor 800 is larger than a predetermined threshold value, thereby detecting a displacement of the lens. When the displacement is detected, the position of the lens is reset before photographing and defocusing can be prevented. In addition, making the direction of movement of a drive shaft for the lens coincide with the direction of the acceleration detected by the acceleration sensor 800 eliminates the need for a three-dimensional acceleration sensor or the like. Accordingly, a space saving can also be achieved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging apparatus and a lens drive control method.

  In the case of camera-equipped mobile phones and camera units that are required to be small and thin, the macro mode and the standard mode have been conventionally switched by operating an external lever. In recent years, some have a small step motor, and thereby have an AF (autofocus) function for moving the lens.

  However, the step motor is limited even if it is downsized. Instead of this, a method of moving the lens by providing a camera unit with a piezoelectric element (piezo element) that can be further reduced in weight and size has been used. The piezoelectric element has a property of deforming according to the magnitude of the applied voltage. The camera unit is equipped with a piezoelectric element having this property, a voltage as a drive signal is supplied to the piezoelectric element, and the piezoelectric element is deformed to drive the lens. A lens driving device that drives a lens with the above piezoelectric element is disclosed in, for example, Patent Document 1.

When driving a lens with a piezoelectric element, the lens is moved using the vibration of a vibration type actuator using the piezoelectric element as a driving force. Since the lens is movable in this vibration direction, if an impact or the like is applied to the lens or the lens driving device after the lens is moved, the lens is moved. If shooting is performed in this state, there is a problem that the zoom magnification is different from the user's desired zoom magnification or out of focus.
In order to solve such a problem, it is conceivable to provide some mechanism for fixing the position of the lens. However, the apparatus becomes larger and the lock / release control becomes complicated.

Similar problems are not limited to camera-equipped mobile phones, but are widely present in optical systems using vibration actuators.
JP 2004-294759 A

The present invention has been made in view of the above circumstances, and an object thereof is to provide an imaging apparatus and a lens driving method that are not easily affected by an impact or the like.
It is another object of the present invention to provide an imaging apparatus and a lens driving method that are small in size and can maintain the lens position at the original position even when an impact or the like is applied.

In order to achieve the above object, an imaging apparatus according to the first aspect of the present invention provides:
A lens,
An acceleration sensor for detecting an external force applied to the imaging device;
Imaging means for imaging a subject through the lens;
An adjusting means comprising a piezoelectric element, applying a voltage to the piezoelectric element to deform it, and adjusting a distance between the lens and the imaging means;
Voltage value acquisition means for acquiring a voltage value generated by the acceleration sensor after adjustment by the adjustment means;
Control means for controlling the adjustment means to readjust when the voltage value acquired by the voltage acquisition means is greater than a predetermined value;
It is characterized by providing.

A lens drive control method according to the second aspect of the present invention is as follows.
An adjustment step of adjusting the distance between the lens of the imaging device and the imaging means for imaging the subject via the lens by applying a voltage to the piezoelectric element and deforming it;
An acceleration detecting step for detecting an external force applied to the imaging device by detecting an acceleration;
A control step for controlling the adjustment step to be re-executed when the acceleration detected in the acceleration detection step is greater than a predetermined level;
It is provided with.

Furthermore, a program according to the third aspect of the present invention is:
In the computer of the imaging device,
An adjustment procedure for adjusting the distance between the lens of the imaging device and the imaging means for imaging the subject via the lens by applying a voltage to the piezoelectric element and deforming it;
An acceleration determination procedure for determining from the output signal of the acceleration sensor that an external force has been applied to the imaging device;
A control procedure for controlling to re-execute the adjustment procedure when the acceleration detected in the acceleration determination procedure is greater than a predetermined level;
Is executed.

  According to the present invention, when an acceleration sensor is mounted on an optical control device, a voltage generated when the acceleration sensor receives acceleration is detected, and when it is determined that the detected voltage is equal to or greater than a certain value, the lens It becomes possible to reset the position of. Thereby, the zoom magnification shift caused by the lens position shift is eliminated, and the user's uncomfortable feeling that the photographed photograph is different from the user's desired zoom magnification is eliminated.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

(Embodiment 1)
FIG. 1 is an external view of a camera-equipped mobile phone 200 including the lens control device according to the first embodiment. 1A shows an external appearance of the front side of the camera-equipped mobile phone 200 with the cover 205 opened, and FIG. 1B shows an external appearance of the back side with the cover 205 opened. Is shown.

  As shown in the figure, the camera-equipped mobile phone 200 has a configuration in which each end portion of a lid portion 205 and a main body portion 207 is connected by a hinge portion 206 and can be folded.

  The camera-equipped mobile phone 200 is similar to a general camera-equipped mobile phone, such as a call speaker 201, a main display unit 202, a key input unit 203, a call microphone 204, a sub display unit 209, a camera unit 210, a strobe LED ( Light Emitting Diode) 211, stereo speaker 212, rechargeable battery 213, and the like.

  Among these components, the key input unit 203 includes a camera key 208a for starting the camera, a decision key 208b for shutter operation, an autofocus lock key 208c for holding a state in which the subject is focused by autofocus, zoom A cursor key 208d for adjusting the magnification is provided.

  The structure of the camera unit 210 is shown in FIGS. FIG. 2A shows the front structure of the camera unit, and FIG. 2B shows the side structure of the camera unit. As shown in FIGS. 2A and 2B, the camera unit 210 includes an imaging device 307, a lens system (hereinafter simply referred to as a lens) 304 that guides external light to the imaging device 307, and the position of the lens 304. A drive mechanism 309 that moves in the axial direction and an acceleration sensor 800 that generates a voltage corresponding to the received acceleration are provided.

The imaging device 307 is composed of a CCD (Charge Coupled Device) or the like, and converts incident light into dot matrix data.
The lens 304 is accommodated in the lens holder 303 and moves integrally with the lens holder 303. The movement of the lens 304 changes the size of the subject of the imaging device 307 (more precisely, the angle of view including the subject). That is, the zoom magnification changes.

  The drive mechanism 309 includes a piezoelectric element (piezo element) 306, a drive shaft 302, an FPCB (Flexible Print Circuit Board) 401, a weight 402, a SUS plate 403, a pressing plate 301, and a pressing spring 305. It is composed of a vibration type actuator, and moves the position of the lens 304 in the direction of its optical axis.

  The piezoelectric element (piezo element) 306 expands and contracts according to the applied voltage. The drive shaft 302 is fixed to one surface of the piezoelectric element 306 and is sandwiched between the lens holder 303 of the lens 304 and the pressing plate 301. The FPCB 401 is fixed to the other surface of the piezoelectric element 306, and a drive circuit for generating a drive signal for driving the piezoelectric element 306 is formed. The weight 402 is fixed to the FPCB 401 and supports the drive shaft 302. The SUS plate 403 is made of a metal plate member, and fixes the weight 402 to the camera unit 210.

  The pressing plate 301 holds the drive shaft 302 between the lens holder 303 and the holding plate 301. The presser spring 305 urges the presser plate 301 in the downward direction and applies appropriate friction between the lens holder 303 and the drive shaft 302.

As shown in FIGS. 3A and 3B, the piezoelectric element 306 expands and contracts by a control (drive) signal from the FPCB 401, and the position of the drive shaft 302 moves as the piezoelectric element 306 expands and contracts.
Here, when the piezoelectric element 306 expands and contracts at a low speed and the drive shaft 302 moves at a low speed, the lens holder 303 also moves due to the frictional force between the drive shaft 302 and the lens holder 303. However, when the expansion / contraction speed of the piezoelectric element 306 is high, the friction portion slips due to inertia, and the lens holder 303 hardly moves and stays at substantially the same position.

  Accordingly, the lens 304 is changed from the state shown in FIG. 3A to the state shown in FIG. 3B at a low speed and the operation shown in FIG. 3B to the state shown in FIG. It is possible to move in the direction indicated by symbol Y1 in (a) and (b). Similarly, the lens 304 is changed to the state shown in FIG. 3B from the state shown in FIG. 3A at a low speed and the state shown in FIG. 3A to the state shown in FIG. 2 (a) and (b) can be moved in the direction indicated by the symbol Y2.

The acceleration sensor 800 can convert the acceleration received by the camera-equipped mobile phone 200 into a voltage value. The acceleration sensor 800 has a structure in which, for example, a capacitor is constituted by two fixed plates that are fixed, and a center plate that is displaced together with the movable base is sandwiched between them. The area of the portion into which the center plate is inserted and the distance between the center plate and the fixed plate change according to the displacement of the center plate. The capacitance changes according to such a change, and the capacitance is converted into a voltage and output.
Further, by setting the direction of acceleration detected by the acceleration sensor 800 to the same direction as the vibration direction of the drive shaft 302, it is not necessary to provide a device such as a three-dimensional acceleration sensor, and space can be saved.

  The camera unit 210 also includes a position measurement mechanism for measuring the position of the lens 304. This position measuring mechanism includes a magnet 310 (shown in FIG. 2A) fixed to the lens holder 303 and a hall element (H / S) 308 disposed on the outer frame of the camera unit 210. The distance between the magnet 310 and the Hall element 308 changes according to the position of the lens holder 303, and the magnetic field intensity detected by the Hall element 308 changes with the change in distance. The position of the holder 303 is detected and determined.

Next, a circuit configuration of the camera-equipped mobile phone 200 will be described.
As shown in FIG. 4, the internal circuit of the camera-equipped mobile phone 200 includes a control unit 108, a key input unit 203 for inputting various instructions and information, the above-described imaging device 307, the above-described Hall sensor 308, and an image memory. 121, an acceleration sensor 800, a drive circuit 111, and the like.

  The control unit 108 includes a microprocessor including a CPU (Central Processing Unit), a RAM (Randam Access Memory), a ROM (Read Only Memory), and the like, and is equipped with this camera based on an operation program stored in the ROM. The operation of each unit in the mobile phone 200 is controlled. In particular, in the present embodiment, the control unit 108 executes imaging-related processing in accordance with an instruction from the key input unit 203. For example, the control unit 108 controls the drive circuit 111 in response to the operation of the cursor key 208d, drives the piezoelectric element 306, adjusts the position of the lens 304, and detects the detection signal from the acceleration sensor 800. In response to this, the position of the lens 304 is readjusted, and processing such as capturing an image from the imaging device 307 and storing it in the image memory 121 is performed in accordance with an instruction from the key input unit 203.

The key input unit 203 responds to the operation of the camera key 208a, instructs the camera to start, shutter instruction (image capture instruction) in response to the operation of the enter key 208b, zoom-in (increase magnification) according to the operation of the cursor key 208d, or A zoom-out (magnification reduction) instruction is supplied to the control unit 108.
The imaging device 307 supplies image data of the captured image to the control unit 108.
The hall sensor 308 supplies a signal indicating the position of the lens 304 to the control unit 108 based on the detected magnetic force.
The image memory 121 includes a flash memory and stores captured image data.

The drive circuit 111 is mounted on the FPCB 401, generates a drive signal for moving the lens 304 in accordance with an instruction from the control unit 108, and supplies the drive signal to the piezoelectric element 306.
The drive circuit 111 includes a power supply unit 101, a drive waveform generation unit 102, a first inverter circuit 104, a second inverter circuit 105, a current limiting resistor R, a power supply stabilization capacitor C, and the like.

  Each inverter circuit 104, 105 is a complementary (CMOS (Complementary Metal Oxide Semiconductor)) inverter circuit composed of P-channel MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) 104a, 105a and N-channel MOSFETs 104b, 105b. .

  The power supply unit 101 supplies a power supply voltage Vcc to the electronic circuit. In response to an instruction from the control unit 108, the drive waveform generation unit 102 generates a pair of drive signals for controlling the piezoelectric element 306, and supplies one drive signal to the first inverter circuit 104 through the wiring 103a. The other drive signal is supplied to the second inverter circuit 105 through the wiring 103b. When the voltage of the signal supplied to the gate voltages of the MOSFETs 104a and 104b is at a high level, only the N-channel MOSFET 104b is turned on, and the voltage at the left electrode of the piezoelectric element 306 is at a low level. On the other hand, when the voltage of the signal supplied to the gate voltages of the MOSFETs 104a and 104b is at a low level, only the P-channel MOSFET 104a is turned on, and the voltage on the left side of the piezoelectric element 306 is substantially the power supply voltage Vcc. Similarly, when the voltage of the signal supplied to the gate voltages of the MOSFETs 105a and 105b is high, only the N-channel MOSFET 105b is turned on, and the voltage of the right electrode of the piezoelectric element 306 is low. Conversely, when the voltage of the signal supplied to the gate voltages of the MOSFETs 105a and 105b is at a low level, only the P-channel MOSFET 105a is turned on, and the voltage on the right side of the piezoelectric element 306 is substantially the power supply voltage Vcc.

  For example, when the drive waveform generation unit 102 receives an instruction to zoom out (zoom magnification reduction) from the control unit 108, the drive waveform generation unit 102 changes to FIGS. 5A and 5B (horizontal axis: time, vertical axis: voltage). As shown, two independent voltage waveforms WA and WB are generated, and the voltage waveform WA of FIG. 5A is applied to the first inverter circuit 104 via the wiring 103a, and the voltage waveform WB of FIG. The voltage is supplied to the second inverter circuit 105 through the wiring 103b. A voltage as shown in FIG. 5C is applied to the electrodes at both ends of the piezoelectric element 306 by both voltage waveforms WA and WB. In FIG. 5C, the state where the voltage of the right electrode of the piezoelectric element 306 shown in FIG. 4 is higher than the voltage of the left electrode is positive. When the voltage waveform WA is at a low level and the voltage waveform WB is at a high level, the voltage applied to the piezoelectric element 306 is −Vp. Further, when the voltage waveform WA is at a high level and the voltage waveform WB is at a low level, the voltage applied to the piezoelectric element 306 is Vp.

  When a voltage as shown in FIG. 5C is applied to the piezoelectric element 306, the piezoelectric element 306 repeatedly contracts at a high speed and extends at a low speed as shown in FIG. The lens 304 moves forward (left side in FIG. 2B), and moves the lens 304 away from the imaging device 307.

  Further, when receiving a zoom-up instruction from the control unit 108, the drive waveform generation unit 102 supplies the voltage waveform WA shown in FIG. 5A to the first inverter 104 via the wiring 103a, and FIG. ) Is supplied to the second inverter 105 via the wiring 103b. Therefore, a voltage obtained by reversing the polarity of the voltage waveform shown in FIG. 5C is applied to the piezoelectric element 306, and the piezoelectric element 306 shows a displacement obtained by reversing the displacement shown in FIG. That is, the operation of expanding at high speed and contracting at low speed is repeated. Accordingly, the lens holder 303 and the lens 304 move rearward (right side in FIG. 2B), and gradually bring the lens 304 closer to the imaging device 307.

  Further, as described above, the acceleration sensor 800 is a sensor that changes the capacitance according to the received acceleration, converts the capacitance into a voltage, and outputs the voltage. As described above, the position of the lens 304 is held by the frictional force between the lens holder 303 and the drive shaft 102. Therefore, when an external force such as an impact is applied, there is a possibility that the position shift occurs. Therefore, the acceleration sensor 800 detects this impact and notifies the control unit 108 of it.

  Here, the acceleration sensor 800 is mounted on the FPCB 401, for example, and supplies the voltage output from the acceleration sensor 800 to the A / D converter 107 that performs analog-digital conversion.

  The A / D converter 107 converts the supplied voltage (analog value) into a digital value and supplies it to the control unit 108. The control unit 108 determines from the digital value supplied from the A / D converter 107 whether or not the power of the acceleration sensor 800 is higher than a certain level, so that any impact / external force is applied in the movable direction of the lens 304. Determine whether or not.

Next, the operation of the camera-equipped mobile phone 200 having the above-described configuration will be described with reference to the flowcharts of FIGS.
When the user wants to take a picture with the camera-equipped mobile phone 200, the user presses the camera key 208a in FIG. In response to this key operation, the control unit 108 sets an imaging mode, activates the camera unit 210, and starts an operation of supplying and displaying the image acquired by the imaging device 307 to the main display unit 202.

When the user wants to enlarge or reduce the display image, the user appropriately operates the cursor key 208d.
In response to this key operation, the control unit 108 starts the processing shown in the flowchart of FIG. 6, and first turns off the acceleration sensor 800 (step S101). The method of turning off is arbitrary, such as stopping the supply of power or masking the input to the control unit 108.

  Next, in response to this key operation, the control unit 108 starts a piezo drive process for driving the piezoelectric element 306 (step S102). Here, for example, if the upper part of the cursor key 208d is pressed, the control unit 108 determines that it is a zoom-in instruction, and sends the drive waveform WA shown in FIGS. 5 (a) and 5 (b) to the drive waveform generation unit 102. Instructs the inverters 104 and 105 to supply WB, respectively. If the lower part of the cursor key 208d is pressed, the control unit 108 determines that it is a zoom-out instruction, and causes the drive waveform generator 102 to display the drive waveforms WA and WB shown in FIGS. 5 (a) and 5 (b). The inverters 105 and 104 are instructed to be supplied respectively. Accordingly, the drive voltage waveform shown in FIG. 5C or its inverted voltage waveform is applied to the piezoelectric element 306, and the piezoelectric element 306 repeatedly expands and contracts to control the position of the lens 304.

  The control unit 108 determines whether or not the lens movement processing is completed, that is, whether or not the pressing of the cursor key 208d is completed, or whether or not the lens 304 has reached the end (from the detection level of the Hall sensor 308). (Step S103), and when it is determined that the processing has not ended (Step S103; No), the operation of the drive waveform generator 102 is continued (Step S102). As a result, the user can move the lens 304 to a desired position and shoot at a desired zoom magnification.

  In the present embodiment, it is assumed that the depth of field of the lens 304 is deep and is always in focus within the movable range of the lens 304.

  On the other hand, if it is determined in step S103 that the process has been completed (step S103; Yes), the control unit 108 measures the output voltage of the Hall element 308 and stores the measured value in the internal memory (for example, FIG. 4). (Step S104). This value indicates the position of the lens at that time.

  Subsequently, the acceleration sensor 800 is turned on (step S105), and the electromotive voltage of the acceleration sensor 800 is measured. This is the end of the current process.

  In this state, when the determination button (shutter button) 208b is pressed, the control unit 108 starts the processing of FIG. 7, captures the captured image of the imaging device 307, and stores it in the image memory 121 (step 301).

  In this way, when the user is using the camera and any impact or external force is applied to the camera-equipped mobile phone 200, the acceleration sensor 800 receives the acceleration and generates a voltage. The acceleration sensor 800 supplies this voltage to the A / D converter 107. The A / D converter 107 converts the supplied voltage (analog value) into a digital value and supplies it to the control unit 108.

  When the digital value is supplied from the A / D converter 107, the control unit 108 captures this as an interrupt signal, for example, and starts the impact detection interrupt process shown in the flowchart of FIG. First, the control unit 108 determines whether or not the supplied digital value is larger than a predetermined threshold value (step S501). This threshold value is a preset value, and is set to a minimum value such that the lens 304 moves.

When the control unit 108 determines that the digital value supplied from the A / D converter 107 is larger than the threshold (step S501; Yes), the control unit 108 notifies the user that the lens may have moved. For example, as shown in FIG. 9, a pop-up display such as “the lens may have been displaced due to impact” is performed (step S502). At this time, the control unit 108 waits for the user to press the determination key 208b for determining whether to reset the lens position. If it is not determined to reset (step S503; No), the impact detection interrupt process is terminated and the next operation is waited. If it is decided to reset (step S503; Yes), the difference between the stored lens position and the current lens position supplied from the hall element 308 is obtained, and the driving waveform and the moving amount of the lens are driven. It supplies to the generation | occurrence | production part 102 (step S504).
The drive waveform generator 102 generates a drive voltage waveform for moving the lens 304 in accordance with the instruction, and moves the lens 304. The control unit 108 may monitor the output of the hall sensor 308 and control the drive waveform generation unit 102 until the lens 304 returns to an appropriate position.

  On the other hand, when the control unit 108 determines that the digital value supplied from the A / D converter 107 is smaller than the threshold value (step S501; No), the control unit 108 performs the impact detection interrupt process without correcting the position of the lens 304. Exit and wait for the next operation.

  As described above, in the camera-equipped mobile phone 200 according to the present embodiment, the control unit 108 determines whether or not the value supplied from the acceleration sensor 800 is larger than a predetermined threshold value. The occurrence of misalignment 304 can be detected. Furthermore, since the position of the lens 304 is reset when the occurrence of the positional deviation is detected, it is possible to prevent the photographing itself while the zoom magnification is deviated.

Further, by using the same piezoelectric element 306 for driving the lens 304 and detecting the impact, the expansion / contraction direction of the piezoelectric element 306 can coincide with the direction in which the impact should be detected, and space saving is achieved. Can also be planned.
In addition, there is no need to provide a stopper for fixing the position of the lens 304, which contributes to a reduction in size and weight.

(Embodiment 2)
In the first embodiment, the camera unit 210 having a configuration in which the depth of field of the lens 304 is deep and is always in focus within the moving range of the lens 304 has been described. For example, the present invention can also be applied to a camera unit that can adjust zoom and focus independently.

When such an adjustment is possible, for example, a plurality of lenses whose positions can be adjusted are arranged at the position of the lens 304 shown in FIG. 2, a vibration type actuator and a drive circuit are arranged on the lens, and each lens is further arranged. The position can be detected.
By separately arranging a plurality of lenses and a plurality of vibration type actuators and drive circuits, it is possible to control the zoom magnification change and the focus independently. Thereby, the depth of field of the lens may be shallow, and a sharp image can be taken.

An operation process of the control unit 108 in the camera unit having such a configuration will be described.
When the user wants to take a picture with the camera-equipped mobile phone 200, when the user presses the camera key 208a in FIG. 2, the camera mode is set and the camera unit 210 is activated.

Here, when the user wants to change the zoom magnification, the user presses the cursor key 208d. The control unit 108 executes the process shown in FIG. 6, supplies drive signals to the plurality of piezoelectric elements, and changes the zoom magnification, for example, by moving each lens in the same direction (step S102). The lens driving method itself is the same as that in the first embodiment.
When the movement of the lens is completed, the control unit 108 stores the position of each lens (step S104).

  The depth of field of the lens according to the present embodiment is shallow, and changing the zoom magnification may cause the lens to be out of focus. Therefore, the user presses the autofocus lock key 208c as necessary. In response to the user's operation, the control unit 108 starts the autofocus process shown in FIG. 10, first turns off the acceleration sensor 800 (step S401), and then drives any one of the piezoelectric elements. Thus, any lens is moved to perform focusing (autofocus process) (step S402, step S403; No). The method for focusing is arbitrary, but for example, a method in which the state where the variance of the luminance value of each pixel of the image captured by the imaging device 307 is the largest is the focused state can be used. . In addition, focusing may be performed by other methods such as a method using contrast and a phase difference detection method.

  Next, when the focusing process is completed (step S403; Yes), the position of each lens in this focused state is overwritten and stored in the internal memory (step S404).

  Subsequently, the control unit 108 activates the acceleration sensor 800 (step S405), and ends the current focus lock process.

  In this way, when an impact or external force is applied to the camera-equipped mobile phone 200 while the user is using the camera, a signal is supplied from the acceleration sensor 800 to the control unit 108. In response to this signal, the control unit 108 starts the impact detection interrupt process shown in the flowchart of FIG. First, the control unit 108 determines whether or not the supplied digital value is larger than a predetermined threshold value (step S501). When the control unit 108 determines that the digital value supplied from the A / D converter 107 is greater than the threshold value (step S501; Yes), the control unit 108 determines the position of each lens in accordance with a user instruction (steps S502 and S503). The drive waveform generation unit is instructed to generate a drive waveform for matching the latest storage position of each lens stored in the memory (step S504).

  With such a configuration, even when an impact is applied, the position of each lens can be returned to an appropriate position after the previous zoom adjustment or after focusing.

  The acceleration sensor 800 may be any sensor as long as it has a function of detecting an external force applied to a camera-equipped mobile phone, such as an electrodynamic acceleration sensor, a strain cage acceleration sensor, or a semiconductor acceleration sensor. Well, it does not depend on its name or structure.

  The appearance, mechanical configuration, circuit configuration, operation, waveform, flowchart, and the like of each of the above-described units are examples, and are arbitrary as long as the same operation and effect can be realized, and is not limited to the above-described embodiment. .

For example, in each of the above-described embodiments, the case where the zoom magnification is continuously changed has been described. However, the zoom magnification is stepped in two steps, three steps, and the like, for example, when switching between the normal mode and the macro mode. The same applies to the case of switching.
Further, when the camera mode is entered, the lens position at that time may be stored.

  Further, for example, the signal generated by the drive waveform generator 102 may not be a rectangular waveform, but may be a sawtooth waveform signal. Further, although the drive circuit of the piezoelectric element 306 is configured by a CMOS inverter circuit, it may be configured by, for example, an H bridge circuit.

  In each of the above embodiments, a mobile communication terminal such as a camera-equipped mobile phone is assumed. However, the present invention is not limited to this, and may be an electronic camera or a small apparatus with another form of camera.

  Further, in each of the above embodiments, the program executed by the control unit 108 is stored in advance in a ROM or the like. However, the present invention is not limited to this, and a program for executing the above-described processing may be applied to an existing camera device so that control similar to the control according to the above-described embodiment can be executed. The method of providing such a program is arbitrary. For example, the program may be provided via a communication medium such as the Internet, or may be stored and distributed in a recording medium such as a memory card.

It is a figure which shows the example of an external appearance structure of the lens control apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of the camera unit in the lens control apparatus which concerns on embodiment of this invention. (A) shows the structure which looked at the camera unit from the front, (b) shows the structure which looked at the camera unit from the side, and is the figure which specified the expansion / contraction direction of the piezoelectric element. It is the figure which showed the state in which the drive shaft in the lens control apparatus which concerns on embodiment of this invention moves. (A) is a figure of the state which the piezoelectric element extended. (B) is a figure of the state which the piezoelectric element shrunk. 1 is a block diagram illustrating a configuration example of a lens control device according to an embodiment of the present invention, and a circuit configuration diagram illustrating a configuration example of an electronic circuit implemented by the lens control device. (A), (b) is a timing chart which illustrates the voltage waveform and generation timing of the signal which the drive waveform generation part in the lens control device concerning the embodiment of the present invention generates. (A) is a voltage waveform supplied to the first inverter, and (b) is a voltage waveform supplied to the second inverter. (C) is the figure which illustrated the time change of the voltage concerning a piezoelectric element. (D) is the figure which illustrated the time displacement of the position of a piezoelectric element. It is a flowchart which shows the operation | movement process of the lens drive process which a control part performs when driving a lens for the zoom magnification change in the lens control apparatus which concerns on embodiment of this invention. It is a flowchart which shows the operation | movement process of the image taking-in process in the lens control apparatus which concerns on embodiment of this invention. It is a flowchart which shows the operation | movement process of the impact detection interruption process in the lens control apparatus which concerns on embodiment of this invention. In embodiment of this invention, it is a figure which shows the example which displayed on the main display part the message that the lens may have moved to the user. It is a flowchart which shows the operation | movement process of the lens drive process which drives the some lens in the lens control apparatus which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Power supply part, 102 ... Drive waveform generation part, 104 ... 1st CMOS inverter circuit, 105 ... 2nd CMOS inverter circuit, 106 ... Operational amplifier (AMP), 107 ... A / D converter (A / D), 108 ... Control unit (holding means, control means), 208a ... camera key, 208b ... decision key, 208c ... autofocus lock key, 208d ... cursor key (instruction means), 302 ... drive shaft, 303 ... lens holder, 304 ... lens 306: Piezoelectric element 307 Imaging device (imaging unit) 401 FPCB 800 Acceleration sensor

Claims (3)

In an imaging device including a lens,
An acceleration sensor for detecting an external force applied to the imaging device;
Imaging means for imaging a subject through the lens;
An adjusting means comprising a piezoelectric element, applying a voltage to the piezoelectric element to deform it, and adjusting a distance between the lens and the imaging means;
Voltage value acquisition means for acquiring a voltage value generated by the acceleration sensor after adjustment by the adjustment means;
Control means for controlling the adjustment means to readjust when the voltage value acquired by the voltage acquisition means is greater than a predetermined value;
An imaging apparatus comprising: An adjustment step of adjusting the distance between the lens of the imaging device and the imaging means for imaging the subject via the lens by applying a voltage to the piezoelectric element and deforming it;
An acceleration detecting step for detecting an external force applied to the imaging device by detecting an acceleration;
A control step for controlling the adjustment step to be re-executed when the acceleration detected in the acceleration detection step is greater than a predetermined level;
A lens drive control method comprising: In the computer of the imaging device,
An adjustment procedure for adjusting the distance between the lens of the imaging device and the imaging means for imaging the subject via the lens by applying a voltage to the piezoelectric element and deforming it;
An acceleration determination procedure for determining from the output signal of the acceleration sensor that an external force has been applied to the imaging device;
A control procedure for controlling to re-execute the adjustment procedure when the acceleration detected in the acceleration determination procedure is greater than a predetermined level;
A program that executes

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