JP2017111247A - Lens barrel and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel capable of reducing condensation and/or cloudiness on an optical element without requiring any dedicated heating means.SOLUTION: The lens barrel includes: a plurality of optical elements; a drive part that drives at least one of the plurality of optical elements; and a control unit that controls the drive part. The control unit is settable between a first mode and a second mode for controlling the drive part. Total caloric value generated by the drive part while the control unit sets the second mode is larger than the first mode.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lens barrel.

  A lens barrel mounted on an imaging apparatus such as a single-lens reflex camera may be used or transported in various shooting environments, and condensation or cloudiness may occur on the lens. The water droplets adhering to the forefront or rearmost surface of the lens constituting the lens barrel can be wiped off by the user himself. However, if condensation or fogging occurs on other lenses, the captured image may be affected. For this reason, it is often impossible to photograph until the condensation or cloudiness disappears, and there is a problem with the rapid photographing property.

  Patent Document 1 discloses a lens barrel that forms a transparent conductive film on the surface of a lens and energizes the transparent conductive film to heat the lens and prevent fogging of the lens.

JP-A-3-33812

  However, since the lens barrel of Patent Document 1 is provided with a dedicated heating means for preventing the lens from fogging, the cost of the lens barrel is high.

  Therefore, the present invention provides a lens barrel and an imaging apparatus that can reduce condensation and fogging of an optical element without providing a dedicated heating means.

  A lens barrel as one aspect of the present invention includes a plurality of optical elements, a drive unit that drives at least one of the plurality of optical elements, and a control unit that controls the drive unit, and the control unit Is capable of setting the first mode and the second mode for controlling the drive unit, and the total heat generation amount of the drive unit while the control unit is setting the second mode is , More than in the first mode.

  An image pickup apparatus according to another aspect of the present invention includes the lens barrel and an image pickup element that photoelectrically converts an optical image formed through the plurality of optical elements.

  Other objects and features of the present invention are illustrated in the following examples.

  According to the present invention, it is possible to provide a lens barrel and an imaging apparatus capable of reducing condensation and fogging of an optical element without providing a dedicated heating unit.

It is sectional drawing of the imaging device in each Example. FIG. 3 is a perspective view of a main part of a lens barrel in Embodiment 1. It is a schematic diagram of the 1st electricity supply pattern in Example 1, and a 2nd electricity supply pattern. 6 is a perspective view of a main part of a lens barrel in Embodiment 2. FIG. FIG. 6 is a perspective view of a main part of a lens barrel in Embodiment 3.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, with reference to FIG. 1, an imaging apparatus according to Embodiment 1 of the present invention will be described. FIG. 1 is a cross-sectional view of an imaging apparatus 10 (camera) in the present embodiment. The imaging apparatus 10 includes an imaging apparatus body 200 (camera body) and a lens barrel 100 (interchangeable lens) that is detachably attached to the imaging apparatus body 200. In FIG. 1, the direction of the optical axis (photographing optical axis) AXL of the lens is the Z direction, and the direction perpendicular to the optical axis AXL is parallel to the imaging surface of the image sensor 6. The X direction and the vertical direction are the Y direction. The imaging device 10 of the present embodiment is a lens interchangeable digital single-lens reflex camera, but is not limited to this. The present embodiment can also be applied to a digital camera in which an imaging apparatus main body and a lens barrel are integrally formed, a mirrorless camera, and the like.

  In the state shown in FIG. 1, the main mirror 3 is disposed on the optical path of the light beam from the lens barrel 100 and reflects a part of the light beam to reflect the penta roof prism 7 and the eyepiece lens 8 (in addition to the viewfinder optical system). ) And transmit the remaining light flux. A sub-mirror 4 is disposed behind the main mirror 3 (on the image side), and the light beam that has passed through the main mirror 3 is reflected and guided to the focus detection unit 5. The main mirror 3 and the sub mirror 4 can be integrally inserted and removed from the optical path by a drive mechanism (not shown).

  The focus detection unit 5 performs focus detection (detection of the focus state of the lens barrel 100) by a so-called known phase difference detection method. The image sensor 6 includes a CCD sensor and a CMOS sensor. On the light receiving surface (imaging surface) of the image sensor 6, an object image (image) by the light beam from the lens barrel 100 is formed. The image sensor 6 photoelectrically converts the formed subject image (optical image) and outputs an image signal (image data). The display panel 9 (display unit) has a function of displaying an image output from a signal processing unit (not shown) that processes a signal from the image sensor 6 and various imaging information.

  The operation unit 15 (operation switch) is operated by the user to select either the first energization pattern (first mode) or the second energization pattern (second mode). The operation unit 15 outputs an operation signal based on the user's operation to the circuit board 206 (control unit), and the circuit board 206 outputs the first energization pattern (first mode) or the second based on the operation signal. An energization pattern (second mode) is set. The operation unit 15 is not limited to an operation switch provided in the imaging apparatus main body 200, and the first mode or the second mode is set by operating the display panel 9 (a display unit that also serves as an operation unit, a touch panel). You may comprise so that it may set.

  The lens barrel 100 includes, in order from the subject side to the image side, a first lens unit 101, a second lens unit 102, a third lens unit 103, a fourth lens unit 104, a fifth lens unit 105, a sixth lens unit 106, A seventh lens unit 107 is included. The first lens unit 101 to the seventh lens unit 107 and the diaphragm unit 205 (a plurality of optical elements) having a diaphragm constitute a part of an imaging optical system including a fixed lens group and a moving lens group. The lens barrel 100 can move the moving lens group in the direction along the optical axis AXL (optical axis direction) by relative movement between a guide cylinder 23 and a cam cylinder 24 described later.

  The second lens unit 102 has a focus lens that receives the driving force from the focus unit 211 and moves in the optical axis direction to adjust the focus. The sixth lens unit 106 has a correction lens that receives a driving force from the image stabilization unit 210 and moves in a direction orthogonal to the optical axis AXL (optical axis orthogonal direction) in order to perform image blur correction. The diaphragm unit 205 is disposed on the object side of the fifth lens unit 105, and has a diaphragm (electromagnetic diaphragm) that adjusts the amount of light flux reaching the imaging apparatus main body 200 side. In each of the embodiments of the present invention, an element that does not have a lens such as a diaphragm is an optical element as long as it functions optically.

  The exterior ring 21 (fixed ring) is fixed to a mount 43 that can be attached to and detached from the imaging apparatus main body 200. The fixed cylinder 22 is fixed to the exterior ring 21. The guide tube 23 is formed with a straight groove (not shown). A cam groove (not shown) is formed in the cam cylinder 24. A cam follower (not shown) is fixed to the mounting portion of the movable lens barrel 208 and is engaged with the rectilinear groove of the guide tube 23 and the cam groove of the cam tube 24. When the cam cylinder 24 is rotated according to the rotation of the zoom ring 41, the crossing position of the rectilinear groove of the guide cylinder 23 and the cam groove of the cam cylinder 24 changes. Thereby, the engagement position of a cam follower (not shown) is moved, and the movable lens barrel 208 can be advanced and retracted in the optical axis direction.

  A diaphragm unit 205 is attached to the movable lens barrel 208. The aperture unit 205 has a drive source 205a. The drive source 205a is fixed to the fixed cylinder 22, and is controlled by a circuit board 206 (control unit) that sends an electrical signal to the drive source. The circuit board 206 and the drive source are connected by a flexible printed board (not shown).

  The zoom ring 41 (operation ring) is rotated by the user during zooming (during zooming). The focus ring 42 (operation ring) is rotated by the user during focus adjustment (when focusing). The focus unit 211 includes a drive source, a key portion, and a protrusion (not shown) that engages with a groove attached to the focus ring 42. With such a configuration, when a release button (not shown) provided on the imaging apparatus body 200 is operated, the imaging apparatus body 200 performs imaging (exposure operation) after autofocus and exposure determination operations. ) To record the captured image.

  The sensor 25 (detection unit) detects the environmental state of the lens barrel 100 (imaging device 10). Here, detecting the environmental state means detecting whether or not the state in the lens barrel 100 is a predetermined state. For example, the sensor 25 is a temperature sensor that detects temperature or a humidity sensor that detects humidity. The circuit board 206 (control unit) sets the second mode based on the signal output from the sensor 25. More specifically, the second mode is set when the circuit board 206 determines that the temperature detection result by the sensor 25 is equal to or less than a predetermined value. Similarly, the second mode is set when it is determined that the humidity detection result by the sensor 25 is equal to or greater than a predetermined value. Note that the sensor 25 may detect the temperature or humidity and perform the above determination instead of the circuit board 206. The determination may be performed by a determination unit provided separately from the circuit board 206 and the sensor 25. good.

  Next, the main part of the lens barrel 100 will be described with reference to FIG. FIG. 2 is a perspective view showing a main part (internal structure) of the lens barrel 100. In the lens barrel 100, the fourth lens unit 104 and the fifth lens unit 105 are each held by a lens holding frame (not shown). The aperture unit 205 has a drive source 205a (drive unit). The diaphragm unit 205 has an attachment portion (not shown), and is attached to a lens holding frame or another cylinder. The circuit board 206 includes a control unit (control circuit) that controls the drive source 205a. Further, the circuit board 206 has a connection portion 206b that is electrically connected to the drive source 205a.

  Next, referring to FIG. 3, a method for reducing condensation or fogging of the lens in the lens barrel 100 will be described. In this embodiment, the drive source 205a is a stepping motor having a plurality of coils. The motor shaft can be rotated by sequentially energizing the plurality of coils and sequentially shifting the attraction or repulsion relationship due to the relationship between the magnetic field generated from the coil and the magnetic field of the magnet. A gear is attached to the shaft of the motor, and the shaft of the motor is interlocked with the drive mechanism of the aperture unit 205.

  The circuit board 206 (control unit) can set the first mode and the second mode. The first mode is a mode for controlling the aperture unit 205 (drive unit) at the time of shooting. Shooting here refers to a shooting mode, and the shooting mode includes a live view mode before the shutter is pressed.

  The second mode is a mode in which the aperture unit 205 is controlled so as to heat the aperture unit 205 (to increase the amount of heat generation). In the first mode (shooting mode), the second mode may not be set without user operation.

  Preferably, the circuit board 206 controls the aperture unit 205 using the first energization pattern so as to drive at least one of the plurality of optical elements in the first mode. On the other hand, in the second mode, the circuit board 206 controls the aperture unit 205 using the second energization pattern so as to keep at least one of the plurality of optical elements at a predetermined position (predetermined state).

  3A and 3B are schematic diagrams of the first energization pattern and the second energization pattern. FIG. 3A shows the first energization pattern, and FIG. 3B shows the second energization pattern. As shown in FIG. 3A, the first energization pattern in the present embodiment is an energization pattern by 1-2 phase driving. In FIG. 3A, the horizontal axis represents time, and the vertical axis represents the voltage applied to each coil. As shown in FIG. 3A, the motor shaft can be rotated by sequentially switching the voltage applied to the coil. An interval indicated by a vertical dashed line corresponds to one cycle, and the number of rotations of the motor can be changed by changing the cycle. However, if the cycle is shorter than a predetermined cycle determined according to the load applied to the motor shaft and the temperature environment, the motor response frequency is exceeded, so the motor shaft does not rotate. For this reason, the period of a 1st electricity supply pattern is set so that it may become longer than a predetermined period.

  As shown in FIG. 3B, the second energization pattern in this embodiment is an energization pattern in which a constant voltage is continuously applied to each coil (drive unit) for a predetermined period. Further, the second energization pattern consumes more power than the first energization pattern. With such an energization pattern, each coil can be heated without rotating the shaft of the motor. FIG. 3B shows a case where both of the two coils are energized. However, only one of the coils may be energized. Alternatively, an energization pattern having a frequency higher than the motor response frequency (a cycle shorter than a predetermined cycle) (that is, an energization pattern obtained by changing the cycle of the first energization pattern to a cycle shorter than the predetermined cycle) Two energization patterns may be used. As the second energization pattern, energization that executes a minute periodic operation (operation that gives an image change that cannot be recognized by the user) that cannot be captured by the finder optical system or the image sensor 6, or an operation that continues to be applied to the end of the drive. A pattern can also be adopted.

  When the drive source 205a is energized with the second energization pattern, the drive source 205a generates heat due to the resistance of the coil. Since the ambient temperature increases due to heat generated by the drive source 205a, condensation or fogging of the lens can be reduced.

  That is, in this embodiment, the heat generation amount of the drive source 205a in the second energization pattern (second mode) is larger than the heat generation amount of the drive source 205a in the first energization pattern (first mode). In addition, the calorific value here means the following. That is, when the time during which the first energization pattern and the second energization pattern are executed is the same, the heat generation amount per unit time in the second energization pattern is larger than the heat generation amount per unit time in the first energization pattern. Means many. In this case, the time during which the second mode is set may be shortened compared to the first mode. Further, when the times of execution are different between the first energization pattern and the second energization pattern, the control may be performed as follows. That is, the total heat generation amount during execution of the second energization pattern may be controlled to be larger than the total heat generation amount during execution of the first energization pattern.

  In this embodiment, since the aperture unit 205 is disposed between the fourth lens unit 104 and the fifth lens unit 105, it is particularly effective for reducing condensation or fogging of these lens units.

  Next, with reference to FIG. 4, the lens barrel in Example 2 of this invention is demonstrated. FIG. 4 is a perspective view of a main part of the lens barrel 100a in the present embodiment. In the lens barrel 100a of the present embodiment, the second energization pattern is supplied to the drive source 205a of the diaphragm unit 205 in that the second energization pattern is supplied to the drive source 210a of the image stabilization unit 210. This is different from the lens barrel 100 of the first embodiment. Since other configurations of the lens barrel 100a are the same as those of the lens barrel 100 of the first embodiment, description thereof is omitted.

  The anti-vibration unit 210 has a drive source 210a. The drive source 210a is electrically connected to the circuit board 206 (control unit) via the connection unit 206b, and the drive source 210a is controlled by the circuit board 206 (control unit). In this embodiment, the drive source 210a is a stepping motor that drives a lock mechanism that holds (regulates) the sixth lens unit 106 at a predetermined position when the image stabilization operation is not performed. By rotating the stepping motor, the lock mechanism is operated via a gear attached to the shaft of the motor.

  When the drive source 210a is energized with the second energization pattern, the drive source 210a generates heat due to the resistance of the coil. Since the ambient temperature increases due to the heat generated by the drive source 210a, condensation or fogging of the lens can be reduced. That is, the heat generation amount of the drive source 210a in the second energization pattern (second mode) is larger than the heat generation amount of the drive source 210a in the first energization pattern (first mode). Note that the meaning of the heat generation amount here is the same as the meaning in the first embodiment, and the preferred control in the case where the time during which both energization patterns are executed is different is also the same as in the first embodiment.

  In the present embodiment, since the image stabilization unit 210 is disposed between the fifth lens unit 105 and the sixth lens unit 106, it is particularly effective for reducing condensation or fogging of these lens units.

  In this embodiment, the drive source 210a is a stepping motor (coil) that drives the lock mechanism of the image stabilization unit 210, but may be a coil for moving the image stabilization unit 210 in a plane orthogonal to the optical axis AXL. . In this case, the second energization pattern is an energization pattern in which a current is continuously supplied to the coil so as to continue to be applied to the end locked in a predetermined position or the driving end when not locked. Further, even when performing periodic motion in a plane orthogonal to the optical axis AXL, the coil is heated without moving the image stabilization unit 210 by applying an energization pattern with a period exceeding the response frequency of the drive mechanism to the drive source. Is possible. In addition, a minute periodic motion that cannot be captured by the finder optical system or the image sensor 6 can be executed.

  Next, with reference to FIG. 5, a lens barrel in Embodiment 3 of the present invention will be described. FIG. 5 is a perspective view of a main part of the lens barrel 100b in the present embodiment. In the lens barrel 100b of the present embodiment, the second energization pattern is supplied to the drive source 205a of the aperture unit 205 in that the second energization pattern is supplied to the drive source 211a of the focus unit 211. This is different from the lens barrel 100 of the first embodiment. Since the other configuration of the lens barrel 100b is the same as that of the lens barrel 100 of the first embodiment, description thereof is omitted.

  The focus unit 211 has a drive source 211a. The drive source 211a is electrically connected to the circuit board 206 (control unit) via the connection unit 206c, and the drive source 211a is controlled by the circuit board 206 (control unit). In the present embodiment, the drive source 211a is a vibration motor provided with a piezoelectric element that operates the drive mechanism by ultrasonic driving. The rotor 211b is rotated by performing periodic motion with a plurality of piezoelectric elements and generating traveling waves. In the present embodiment, the second energization pattern is a standing wave that keeps the rotor 211b at the current position. Thereby, the drive source 211a (piezoelectric element) can be heated without rotating the rotor 211b.

  As in the first embodiment, if the cycle is shorter than a predetermined cycle determined according to the load applied to the shaft of the motor (rotor 211b) and the temperature environment, the motor response frequency is exceeded, so the rotor 211b does not rotate. In the present embodiment, an energization pattern that supplies power at a frequency higher than the response frequency may be the second energization pattern. Further, an energization pattern that continues to be applied to the end of the drive mechanism may be used.

  In this embodiment, the drive source 211a is a piezoelectric element, but it may be a drive mechanism that has a guide bar and a screw and converts the rotation of the stepping motor into a straight motion through the screw. In this case, the same pattern as that of the first embodiment can be applied as the second energization pattern. That is, a pattern in which a constant voltage is continuously applied, a pattern in which a voltage is applied with a period equal to or higher than the response frequency, a pattern in which a minute periodic motion that cannot be captured by the finder optical system or the image sensor 6 is applied, or a pattern that continues to be applied to the driving end. Pattern is applicable. The drive source 211a may be a direct current motor. In this case, the second energization pattern is preferably a pattern that is applied with a period equal to or higher than the response frequency, a minute period pattern that cannot be captured by the finder optical system or the image sensor 6, or a pattern that continues to be applied to the driving end. .

  In this embodiment, the circuit board 206 supplies the second energization pattern to the drive source 211a that moves the focus lens in the optical axis direction, but the present invention is not limited to this. Instead of the focus lens, the second energization pattern may be supplied to a drive source that moves the zoom lens.

  In the above-described first to third embodiments, the case where the second energization pattern is supplied to the driving units of the diaphragm unit 205, the image stabilization unit 210, and the focus unit 211 has been described. However, the present invention is not limited thereto. Absent. For example, by combining the first to third embodiments, it is possible to reduce condensation or fogging more effectively for a plurality of lenses. Preferably, the drive unit includes a first drive unit and a second drive unit that drive the first optical element and the second optical element, respectively, of the plurality of optical elements. The two driving units are arranged at different positions in the circumferential direction around the optical axis AXL. More preferably, the first drive unit and the second drive unit are arranged so that the phases are substantially equally divided (alternate). With such a configuration, condensation or fogging can be more effectively and uniformly reduced. The drive unit is not limited to a stepping motor, a vibration motor provided with a piezoelectric element, or a direct current motor, and may be another motor such as a voice coil motor.

  Note that energization with the second energization pattern is based on a detection signal from the detection unit, but energization with the second energization pattern is not limited to non-shooting. For example, when the camera shake correction is off, the drive coil of the image stabilization unit is energized with the second energization pattern, and when the camera shake correction is on, the drive source of the lock mechanism is energized. Even in such a case, it is possible to reduce condensation or fogging.

  According to each embodiment, it is possible to provide a lens barrel and an imaging apparatus that can reduce condensation and fogging of an optical element without providing a dedicated heating unit.

  As mentioned above, although the preferable Example of this invention was described, this invention is not limited to these Examples, A various deformation | transformation and change are possible within the range of the summary.

205 Aperture unit (optical element)
210 Anti-vibration unit (optical element)
211 Focus unit (optical element)
205a, 210a, 211a Drive source (drive unit)
206 Circuit board (control unit)

Claims (19)

A plurality of optical elements;
A drive unit that drives at least one of the plurality of optical elements;
A control unit for controlling the driving unit,
The control unit can set a first mode and a second mode for controlling the drive unit, and
The lens barrel characterized in that the total heat generation amount of the drive unit while the control unit is setting the second mode is larger than that in the first mode.   2. The lens mirror according to claim 1, wherein the heat generation amount of the drive unit per unit time in the second mode is larger than the heat generation amount of the drive unit per unit time in the first mode. Tube. The controller is
In the first mode, the drive unit is controlled using a first energization pattern so as to drive at least one of the plurality of optical elements,
3. The drive unit is controlled by using a second energization pattern so as to keep at least one of the plurality of optical elements at a predetermined position in the second mode. 4. The lens barrel described.   The lens barrel according to claim 3, wherein the second energization pattern is an energization pattern in which a constant voltage is continuously applied to the drive unit for a predetermined period.   The lens barrel according to claim 3, wherein the second energization pattern is an energization pattern having a frequency higher than a response frequency of the drive unit.   The lens barrel according to any one of claims 3 to 5, wherein the second energization pattern consumes more power than the first energization pattern. It further has a detection unit for detecting the environmental state,
The lens barrel according to any one of claims 1 to 6, wherein the control unit sets the second mode based on a signal output from the detection unit.   The lens barrel according to claim 7, wherein the detection unit is a temperature sensor that detects a temperature.   The lens barrel according to claim 7, wherein the detection unit is a humidity sensor that detects humidity.   The lens barrel according to claim 1, wherein the control unit sets the second mode based on an operation signal based on a user operation.   The lens barrel according to any one of claims 1 to 10, wherein the driving unit drives an electromagnetic diaphragm among the plurality of optical elements.   The lens according to claim 1, wherein the driving unit drives a correction lens for performing image blur correction among the plurality of optical elements in a direction orthogonal to an optical axis. A lens barrel.   The lens barrel according to claim 1, wherein the driving unit holds a correction lens for performing image blur correction among the plurality of optical elements at a predetermined position.   The lens barrel according to claim 1, wherein the driving unit moves a focus lens or a zoom lens among the plurality of optical elements in an optical axis direction.   The lens barrel according to claim 1, wherein the driving unit includes a stepping motor, a voice coil motor, a vibration motor including a piezoelectric element, or a DC motor. The drive unit is
A first drive unit for driving a first optical element among the plurality of optical elements;
A second drive unit for driving a second optical element among the plurality of optical elements,
16. The lens barrel according to claim 1, wherein the first driving unit and the second driving unit are arranged at different positions in the optical axis direction. The drive unit is
A first drive unit for driving a first optical element among the plurality of optical elements;
A second drive unit for driving a second optical element among the plurality of optical elements,
The said 1st drive part and the said 2nd drive part are arrange | positioned in the mutually different position in the circumferential direction centering on an optical axis, The one of Claim 1 thru | or 16 characterized by the above-mentioned. Lens barrel. The lens barrel according to any one of claims 1 to 17,
An image pickup device comprising: an image pickup device that photoelectrically converts an optical image formed through the lens barrel. An operation unit that outputs an operation signal based on a user operation;
The imaging device according to claim 18, wherein the control unit sets the second mode based on the operation signal.