JP2008051955A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera with an optical camera shake correction function by which sufficient optical resolution is obtained when optical camera shake correction is not performed. <P>SOLUTION: The camera is equipped with: a photographic optical system 2; sensors 6 and 7 detecting the deflection of an optical axis; a movable part 10 moving a correction lens 2a on a plane perpendicular to the optical axis on the basis of a result obtained by detecting the deflection; and an operation part 9 receiving a user's instruction to select whether or not the optical camera shake correction is performed by controlling the movable part. It is equipped with a control part which controls to perform the camera shake correction by a first adjusting method based on a first adjustment value when execution of the camera shake correction is selected by the operation part, and to hold the correction lens at a predetermined position by controlling the movable part on the basis of a second adjustment value for setting the position detecting resolution of the correction lens to be higher than the first adjustment value when the execution of the camera shake correction is not selected. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a camera that captures a subject image, and more particularly, to a camera having an optical camera shake correction function.

2. Description of the Related Art Conventionally, cameras that correct optical axis blurring in a photographic optical system are known. Such a camera corrects camera shake by physically moving a correction lens included in the photographing optical system (see, for example, Patent Document 1). Note that when the optical camera shake correction is not performed, such as when shooting using a tripod, control for holding the correction lens in the center is performed.
Hei 10-42188

  By the way, especially in an electronic camera, the optical resolution required for a photographing lens is improved with the increase in the number of pixels and the miniaturization of an image sensor. However, the above-described control for holding the correction lens in the center has a relatively large control error and may not be able to cope with the optical resolution required for the photographing lens. Therefore, when optical camera shake correction is not performed, a technology that improves the optical resolution by fixing the correction lens in the center using a mechanical lens fixing part such as an electromagnetic lock can be considered. There are problems such as a cost for providing a lens fixing unit, a space problem, and an increase in the size of a circuit for driving the lens fixing unit.

  The present invention provides a camera having an optical camera shake correction function and capable of obtaining a sufficient optical resolution without providing a special configuration when optical camera shake correction is not performed. With the goal.

  The camera of the present invention includes an image sensor, a photographing optical system that forms a subject image on the image sensor, a blur detection unit that detects blurring of the optical axis in the photographing optical system, and a detection result obtained by the blur detection unit. Based on this, a moving unit that moves the correction lens included in the photographing optical system on a plane perpendicular to the optical axis of the photographing optical system, and whether or not to perform the optical camera shake correction by controlling the moving unit. An operation unit that accepts a user instruction to select the adjustment, and the adjustment related to the correction lens is performed based on the first adjustment method to calculate the first adjustment value, and the correction lens of the correction lens is more than the first adjustment method. When the calculation unit for calculating the second adjustment value based on the second adjustment method for setting the position detection resolution high and the execution of the optical camera shake correction are selected by the operation unit, the first adjustment value is calculated. Based on the adjustment value of If the optical camera shake correction is executed by controlling the moving unit, and the execution of the optical camera shake correction is not selected by the operation unit, the moving unit is controlled based on the second adjustment value. And a control unit that performs control to hold the correction lens at a predetermined position.

  Preferably, when performing the adjustment relating to the correction lens based on the first adjustment method, the calculation unit sets a movable range of the correction lens by the moving unit to a first range, and When performing the adjustment relating to the correction lens based on the second adjustment method, the movable range of the correction lens by the moving unit is set to a second range narrower than the first range, and the control unit When performing the optical camera shake correction based on the first adjustment value, the movable range of the correction lens by the moving unit is set to the first range, and the second adjustment value is set. When performing control to hold the correction lens at a predetermined position based on this, the movable range of the correction lens by the moving unit may be set to the second range.

Preferably, the calculation unit calculates the second adjustment value based on the second adjustment method based on a result of calculating the first adjustment value based on the first adjustment method. You may do it.
Preferably, the control unit further includes a determination unit that determines whether or not the optical camera shake correction is necessary when execution of the optical camera shake correction is selected by the operation unit. If the determination unit determines that the optical camera shake correction is unnecessary, the correction is performed based on the second adjustment value even if execution of the optical camera shake correction is selected by the operation unit. Control to hold the lens in a predetermined position may be performed.

  According to the camera of the present invention, in a camera having an optical camera shake correction function, sufficient optical resolution can be obtained without providing a special configuration when optical camera shake correction is not performed.

The best mode for carrying out the present invention will be described below with reference to the drawings. In this embodiment, an electronic camera will be described as an example of the camera of the present invention.
As shown in FIG. 1A, the electronic camera 1 of the present embodiment moves a photographing optical system 2, a CCD (Charge Coupled Device) 3, and a part of the correction lens 2a of the photographing optical system 2 as shown in FIG. 1A. A correction lens driving unit 4 for correction, a correction lens position detection circuit 5 for detecting the position of the correction lens 2a, a sensor 6 and a sensor 7 for detecting blurring of the optical axis in the photographing optical system 2, and a control unit 8 for controlling each part. The control unit 8 controls the correction lens driving unit 4 in accordance with the detection results of the sensors 6 and 7, and performs optical camera shake correction (hereinafter referred to as “camera shake correction”) described later. Further, the electronic camera 1 includes an operation unit 9 including a release button, a power button, and a member for selecting ON / OFF of camera shake correction, and the state of the operation unit 9 is detected by the control unit 8.

The correction lens 2 a of the photographing optical system 2 is tilted or shifted on a plane perpendicular to the optical axis of the photographing optical system 2 by the correction lens driving unit 4. The CCD 3 captures an image and reads the captured image in accordance with control by the control unit 8.
The sensor 6 detects a blur in the arrow Rx direction as an angular velocity, and the sensor 7 detects a blur in the arrow Ry direction as an angular velocity. Then, the sensor 6 and the sensor 7 supply the detection result to the control unit 8.

  FIG. 1B is an enlarged view of the vicinity of the correction lens 2a. The correction lens 2a is fixed to the movable portion 10 that can move in the X-axis and Y-axis directions of FIG. 1A. A position detecting magnet 11 and a correction lens driving magnet 12 are fixed to the movable portion 10. The electronic camera 1 includes a hall element 13 in a portion facing the position detection magnet 11 and a coil 14 in a portion facing the correction lens driving magnet 12. The output of the Hall element 13 is supplied to the correction lens position detection circuit 5. When the correction lens 2a moves, the magnetic field generated by the position detection magnet 11 changes. The Hall element 13 detects this change in the magnetic field. The correction lens position detection circuit 5 detects the position of the correction lens 2 a based on the output of the hall element 13. The correction lens position detection circuit 5 has two pairs in the X-axis direction and the Y-axis direction, and detects the position of the correction lens 2a on a plane perpendicular to the optical axis of the correction lens 2a.

The correction lens drive unit 4 drives the entire movable unit 10 by supplying a current to the electromagnetic actuator including the correction lens drive magnet 12 and the coil 14 in accordance with an instruction from the control unit 8.
FIG. 2A is a diagram illustrating a movable range of the correction lens 2a. The correction lens 2a can be mechanically moved by the correction lens driving unit 4 to a range indicated by E1 in FIG. 2A. However, when camera shake correction is ON, the control unit 8 limits the movable range of the correction lens 2a to a substantially regular octagonal range indicated by E2 in FIG. 2A. When the photographing optical system 2 has a zoomable configuration, the movable range E2 of the correction lens 2a when the camera shake correction is ON may be changed according to the focal length. When camera shake correction is OFF, the control unit 8 controls each unit so as to hold the correction lens 2a at the center.

The overall flow when the electronic camera 1 having the above-described configuration is turned on will be described with reference to the flowchart of FIG.
In step S1, the control unit 8 determines whether or not the power source of the electronic camera 1 is turned on. The control unit 8 stands by until the power of the electronic camera 1 is turned on. When the power of the electronic camera 1 is turned on, the control unit 8 proceeds to step S2.

In step S2, the control unit 8 performs offset voltage adjustment and hall element drive current adjustment. Offset voltage adjustment and hall element drive current adjustment are initial adjustments performed when the power is turned on. Details of the contents will be described later.
In step S3, the control unit 8 calculates a first adjustment value based on the first correction lens position adjustment method. The first adjustment value is an adjustment value used when camera shake correction is ON. Details of the contents will be described later.

In step S4, the control unit 8 calculates a second adjustment value based on the second correction lens position adjustment method. The second adjustment value is an adjustment value used when camera shake correction is OFF. Details of the contents will be described later.
In step S <b> 5, the control unit 8 determines whether camera shake correction is enabled by the operation unit 9 (whether camera shake correction is ON). The controller 8 proceeds to step S6 when camera shake correction is enabled, and proceeds to step S7 described later when camera shake correction is not enabled.

In step S6, the control unit 8 controls the correction lens driving unit 4 based on the first adjustment value calculated in step S3 to execute optical camera shake correction.
When the camera shake correction is not effective, in step S7, the control unit 8 controls the correction lens driving unit 4 based on the second adjustment value calculated in step S4, so that the correction lens 2a is centered. The control to hold is performed.

[1] Offset voltage adjustment / Hall element drive current adjustment described in step S2 Details of the offset voltage adjustment / Hall element drive current adjustment will be described with reference to the timing chart of FIG. Offset voltage adjustment and Hall element drive current adjustment are adjustments performed when the power is turned on. By this adjustment, the output of the correction lens position detection circuit 5 can be adjusted within a predetermined output effective range. Therefore, detection errors of the correction lens position detection circuit 5 due to temperature fluctuations, circuit fluctuations, and the like can be suppressed.

As shown in FIG. 4, when the power source of the electronic camera 1 is turned on in (1), the control unit 8 performs automatic adjustment by setting the offset voltage adjustment and the Hall element drive current predetermined in (2). Do. Then, the control unit 8 stores the offset voltage adjustment and the Hall element drive current in a memory (not shown) in the control unit 8 based on the result of the automatic adjustment (3).
When the power (control) of the correction lens position detection circuit 5 is once turned off and turned on again, the value stored in the memory is used again.

[2] Calculation of the first adjustment value based on the first correction lens position adjustment method described in step S3 Regarding the calculation of the first adjustment value based on the first correction lens position adjustment method, the correction lens of FIG. This will be described with reference to the schematic diagram of the position and the timing chart of FIG. Note that (1) to (15) in FIGS. 5 and 6 correspond to each other. Hereinafter, the position adjustment of the correction lens 2a with respect to the X axis will be described. The same applies to the Y axis.

  As shown in FIGS. 5 and 6, the control unit 8 controls the correction lens position detection circuit 5 in (1) to decrease the hall element drive current Vhi (X) by a predetermined amount from the current value, thereby driving the hall element. When the time T0 or more has elapsed (2) until the fluctuation of the correction lens position detection circuit output Vho (X) due to the decrease in the current Vhi (X) has subsided (2), the correction lens driving unit 4 is controlled to move the correction lens 2a within the movable range. -Drive to the end.

In (2), the driving of the correction lens 2a to the minus end of the movable range is started, the correction lens 2a is pressed against the minus end of the movable range, and after the time T1 elapses until the position of the correction lens 2a is stabilized ( In 3), the control unit 8 operates the offset voltage adjustment signal Vhs (X) to adjust the correction lens position detection circuit output Vho (X) to a predetermined voltage Vho-C.
Specifically, the offset voltage adjustment signal Vhs (X) is changed stepwise with an interval of a predetermined time T2 or more.

Finally, in (5) after the elapse of a predetermined time T2 from (4) ′ in which the offset voltage adjustment signal Vhs (X) is operated (4) ′, the control unit 8 confirms the output voltage of the correction lens position detection circuit 5, and “Vho -".
In (6) to (7), the control unit 8 controls the correction lens driving unit 4 to drive the correction lens 2a to the + end of the movable range. In (6), the driving of the correction lens 2a to the + end of the movable range is started, the correction lens 2a is pressed against the + end of the movable range, and after the time T1 elapses until the position of the correction lens 2a is stabilized (7 ), The control unit 8 checks the output voltage of the correction lens position detection circuit 5 and sets it to “Vho +”.

Based on “Vho−” confirmed in (5) and “Vho +” confirmed in (7), the control unit 8 calculates the Hall element drive current Vhi (X) in (8) and drives it. The Hall element 13 is driven with a current.
In (9) after at least the predetermined time T0 has elapsed since the Hall element 13 was driven in (8), the control unit 8 operates the offset voltage adjustment signal Vhs (X) to correct the correction lens position detection circuit output Vho. (X) is adjusted to a predetermined voltage Vho-L or Vho-H.

Whether to adjust to Vho-L or Vho-H is determined according to the relationship between “Vho−” confirmed in (5) and “Vho +” confirmed in (7). For example, if “Vho−” ≦ “Vho +”, adjust to Vho−H, otherwise adjust to Vho−L. The specific method of adjustment is the same as (3), (4), (4) ′.
Finally, in (11) after a predetermined time T2 has elapsed since (10) ′ in which the offset voltage adjustment signal Vhs (X) is operated (10) ′, the control unit 8 confirms the output voltage of the correction lens position detection circuit 5, and “Vho + "

In (12), the control unit 8 controls the correction lens driving unit 4 to drive the correction lens 2a to the minus end of the movable range.
In (12), the driving of the correction lens 2a to the minus end of the movable range is started, the correction lens 2a is pressed against the minus end of the movable range, and after the time T1 has elapsed until the position of the correction lens 2a is stabilized (13 ), The control unit 8 checks the output voltage of the correction lens position detection circuit 5 and sets it to “Vho−”. Next, the control unit 8 calculates a correction lens position (γ value) Kγ and a shift value Ks based on “Vho +” confirmed in (11) and “Vho−” confirmed in (13). .

  When the calculation of the correction lens position Kγ and the shift value Ks is finished in (13), the control unit 8 controls the correction lens driving unit 4 in (14) to stop driving both axes of the correction lens 2a. Then, after the predetermined time T3 or more has elapsed, the correction lens 2a is driven in the X axis and the Y axis so that the correction lens 2a is released from the state where it is pressed against any end of the movable range and the subsequent operation is not hindered. The amount is set to 0, and the series of adjustments is completed.

[3] Calculation of second adjustment value based on second correction lens position adjustment method described in step S4 Correction lens of FIG. 7 regarding calculation of second adjustment value based on second correction lens position adjustment method This will be described with reference to the schematic diagram of position and the timing chart of FIG. Note that (13) to (20) in FIGS. 7 and 8 correspond to each other. Moreover, (13) to (14) in FIGS. 7 and 8 correspond to (13) to (20) in FIGS. 5 and 6. That is, the correction lens position adjustment for camera shake correction OFF described below is performed subsequent to the correction lens position adjustment for camera shake correction ON described in FIGS. 5 and 6. Hereinafter, the position adjustment of the correction lens 2a with respect to the X axis will be described. The same applies to the Y axis.

  It should be noted that in the correction lens position adjustment when the camera shake correction is OFF, the movable range of the correction lens 2a is set narrower than when the camera shake correction is ON. When the camera shake correction is OFF, the correction lens 2a is controlled to maintain the center. However, due to the influence of gravity or the like, for example, some shaking occurs in the vicinity of the center shown in the range E3 in FIG. 2B. In other words, since it is movable only within the range E3 in FIG. 2B, the control unit 8 limits the movable range of the correction lens 2a to a substantially regular octagonal range indicated by E4 in FIG. 2B. As a result, the detection accuracy in the correction lens position detection circuit 5 can be improved, and as a result, the optical resolution in the photographing optical system 2 when camera shake correction is OFF can be improved.

  As shown in FIGS. 7 and 8, the controller 8 calculates the Hall element drive current Vhi (X) in (14), and drives the Hall element 13 with the drive current. However, when the calculated hall element drive current Vhi (X) exceeds a predetermined limit value, the value is limited to this range. Further, if the Hall element drive current Vhi (X) before calculating the Hall element drive current Vhi (X) has already exceeded a predetermined limit value, the Hall element drive current Vhi (X) is not changed.

In (15) after a predetermined time T0 or more has elapsed since the Hall element drive current Vhi (X) was operated in (14), the control unit 8 operates the offset voltage adjustment signal Vhs (X) to correct the correction lens position. The detection circuit output Vho (X) is adjusted to a predetermined voltage Vho-L or Vho-H.
Whether to adjust to Vho-L or Vho-H is the same as (9), (10), (10) ′ of the correction lens position adjustment for the above-described camera shake correction ON. The operation method of the offset voltage adjustment signal Vhs (X) is the same.

  Finally, in (17) after a predetermined time T2 has elapsed since (16) ′ in which the offset voltage adjustment signal Vhs (X) is operated (16) ′, the control unit 8 confirms the output voltage of the correction lens position detection circuit 5, and “Vho -'". Next, the control unit 8 calculates a correction lens position Kγ ′ and a shift value Ks ′ for camera shake correction OFF based on the obtained “Vho− ′”. Based on the correction lens position Kγ for camera shake correction ON calculated in (13) of the correction lens position adjustment for camera shake correction ON described above, the correction lens position Kγ ′ for camera shake correction OFF is calculated. calculate.

  When the calculation of the correction lens position Kγ ′ and the shift value Ks ′ for camera shake correction OFF is finished in (17), the control unit 8 in (18), the Hall element drive current Vhi (X) and the offset voltage adjustment signal. Vhs (X) is returned to the state before the correction lens position adjustment for the camera shake correction OFF (see (13)). Note that the setting order of the Hall element drive current Vhi (X) and the offset voltage adjustment signal Vhs (X) may be set first or may be set simultaneously.

Next, the control unit 8 controls the correction lens driving unit 4 and stops driving both axes of the correction lens 2a. Then, after the predetermined time T3 or more has elapsed, the correction lens 2a is driven in the X axis and the Y axis so that the correction lens 2a is released from the state where it is pressed against any end of the movable range and the subsequent operation is not hindered. The amount is set to 0, and the series of adjustments is completed.
By the adjustment described above, the linearity can be obtained without the output voltage of the correction lens position detection circuit 5 being saturated and within the movable range of the correction lens 2a.

  As described above, according to the present embodiment, the imaging device, the imaging optical system that forms the subject image on the imaging device, the blur detection unit that detects optical axis blur in the imaging optical system, and the blur detection unit Based on the detection result by the camera, a moving unit that moves the correction lens included in the photographic optical system on a plane perpendicular to the optical axis of the photographic optical system, and whether to perform optical camera shake correction by controlling the moving unit An operation unit that accepts a user instruction to select whether or not and performs adjustment related to the correction lens based on the first adjustment method, calculates a first adjustment value, and detects the position of the correction lens more than the first adjustment method. A calculation unit that calculates a second adjustment value based on a second adjustment method for setting a high resolution. Then, when execution of the optical image stabilization is selected by the operation unit, the optical image stabilization is executed by controlling the moving unit based on the first adjustment value, and the optical operation is performed by the operation unit. When execution of blur correction is not selected, control is performed to hold the correction lens at a predetermined position by controlling the moving unit based on the second adjustment value. Therefore, in a camera equipped with an optical image stabilization function, when optical image stabilization is not performed, a sufficient optical resolution can be obtained without providing a special configuration such as a fixing part for electrically fixing the correction lens. Can be obtained.

  Further, according to the present embodiment, when performing the adjustment relating to the correction lens based on the first adjustment method, the calculation unit sets the movable range of the correction lens by the moving unit to the first range, and the second range. When performing adjustment related to the correction lens based on the adjustment method, the movable range of the correction lens by the moving unit is set to a second range that is narrower than the first range. Then, when performing optical camera shake correction based on the first adjustment value, the movable range of the correction lens by the moving unit is set to the first range, and the correction lens is set based on the second adjustment value. When performing control to hold at a predetermined position, the movable range of the correction lens by the moving unit is set to the second range. Therefore, the position of the correction lens can be detected accurately and precisely, and the accuracy of holding the correction lens in the center can be improved. As a result, high optical resolution can be obtained.

Further, according to the present embodiment, the calculation unit calculates the second adjustment value based on the second adjustment method based on the result of calculating the first adjustment value based on the first adjustment method. . Therefore, a series of adjustments can be performed quickly and accurately.
In the present embodiment, when camera shake correction is enabled by the user (camera shake correction is ON), it may be configured to determine whether or not camera shake correction is necessary. That is, when camera shake correction is enabled by the operation unit 9, the control unit 8 determines whether camera shake correction is necessary according to whether a tripod is used, the outputs of the sensors 6 and 7, and the like. To do. When it is determined that camera shake correction is unnecessary, control is performed to hold the correction lens in the center based on the second adjustment value even if camera shake correction is enabled by the user. With such a configuration, when camera shake correction is unnecessary, the correction lens can be held in the center based on the second adjustment value, and sufficient optical resolution can be obtained.

In the present embodiment, an example is shown in which adjustment based on different adjustment values is performed when camera shake correction is ON and when camera shake correction is OFF. A plurality of adjustment values may be provided depending on the balance of the optical resolution, and may be selected by a user operation or the like.
In this embodiment, the electronic camera 1 has been described as an example of the present invention. However, the present invention may be applied to an electronic camera in which the lens barrel portion can be replaced. In addition, the present invention can be similarly applied to a silver halide camera having a camera shake correction function.

  In the present embodiment, an example in which the optical camera shake correction is performed by shifting the correction lens 2a has been shown. However, instead of the correction lens 2a, the CCD 3 is tilted on a plane perpendicular to the optical axis of the photographing optical system 2. Alternatively, the present invention can be similarly applied to a configuration in which optical camera shake correction is performed by shifting.

1 is a diagram illustrating a configuration of an electronic camera 1. FIG. It is a figure which shows the movable range of the correction lens 2a. 3 is a flowchart showing an overall flow when the electronic camera 1 is powered on. It is a timing chart of offset voltage adjustment and Hall element drive current adjustment. It is a schematic diagram which shows the correction lens position at the time of calculation of the 1st adjustment value based on the 1st correction lens position adjustment method. It is a timing chart of calculation of the 1st adjustment value based on the 1st correction lens position adjustment method. It is a schematic diagram which shows the correction lens position at the time of calculation of the 2nd adjustment value based on the 2nd correction lens position adjustment method. It is a timing chart of calculation of the 2nd adjustment value based on the 2nd correction lens position adjustment method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electronic camera, 2 ... Imaging optical system, 2a ... Correction lens, 3 ... CCD, 4 ... Correction lens drive part, 5 ... Correction lens position detection circuit, 6 * 7 ... Sensor, 8 ... Control part, 9 ... Operation part , 10 ... Movable part, 11 ... Position detection magnet, 12 ... Correction lens driving magnet, 13 ... Hall element, 14 ... Coil

Claims (4)

An image sensor;
A photographing optical system for forming a subject image on the image sensor;
A blur detection unit that detects blurring of the optical axis in the photographing optical system;
A moving unit that moves a correction lens included in the photographing optical system on a plane perpendicular to the optical axis of the photographing optical system based on a detection result by the blur detection unit;
An operation unit that receives a user instruction to select whether to perform optical camera shake correction by controlling the moving unit;
A second adjustment method for adjusting the correction lens based on the first adjustment method, calculating a first adjustment value, and setting the position detection resolution of the correction lens higher than that of the first adjustment method. A calculation unit for calculating the second adjustment value based on
When execution of the optical camera shake correction is selected by the operation unit, the optical camera shake correction is executed by controlling the moving unit based on the first adjustment value. A control unit that performs control to hold the correction lens at a predetermined position by controlling the moving unit based on the second adjustment value when execution of the optical camera shake correction is not selected. A camera characterized by that. The camera of claim 1,
When performing the adjustment relating to the correction lens based on the first adjustment method, the calculation unit sets a movable range of the correction lens by the moving unit to a first range, and performs the second adjustment method. When performing the adjustment related to the correction lens based on, the movable range of the correction lens by the moving unit is set to a second range narrower than the first range,
When executing the optical camera shake correction based on the first adjustment value, the control unit sets a movable range of the correction lens by the moving unit to the first range, and the second range. When performing control to hold the correction lens at a predetermined position based on the adjustment value, a movable range of the correction lens by the moving unit is set to the second range. The camera of claim 1,
The calculation unit calculates the second adjustment value based on the second adjustment method based on a result of calculating the first adjustment value based on the first adjustment method. Camera. The camera of claim 1,
A determination unit that determines whether or not the optical camera shake correction is necessary when execution of the optical camera shake correction is selected by the operation unit;
When the determination unit determines that the optical camera shake correction is unnecessary, the control unit performs the second adjustment even if execution of the optical camera shake correction is selected by the operation unit. A camera that controls to hold the correction lens at a predetermined position based on a value.

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