Optical equipment and camera systems

Abstract

To provide an optical instrument that can detect an original point even in a collapsed state.SOLUTION: An optical instrument has: a holding frame that holds an optical system; an intermediate member that has a part to be detected; a driving unit that moves the intermediate member in a direction along an optical axis of the optical system; an urging member that urges the holding frame in a direction along the optical axis with respect to the intermediate member; and a detection unit that detects the part to be detected. The optical instrument includes a first state to bring part of the holding frame into contact with part of the intermediate member according to an urging force of the urging member, and a second state to separate the holding frame from the intermediate member against the urging force of the urging member. The driving unit can move the intermediate member in the direction along the optical axis in both the first state and the second state, and the detection unit can detect the part to be detected in at least the second state.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to an optical instrument and a camera system. [Background technology]

[0002] In recent years, optical devices such as digital cameras, video cameras, and interchangeable lenses have been required to be more portable, and the adoption of a retractable mechanism has led to a reduction in size, especially when not in use. A retractable mechanism reduces the spacing between lens groups when transitioning from a state in which photography is possible to a retracted state in which photography is restricted, thereby shortening the overall length of the optical device along its optical axis.

[0003] Patent Document 1 discloses, as an example of a retractable mechanism, a digital camera whose overall length is shortened by narrowing the range of movement of the focus group in particular in a retracted state in which photography is restricted. The retractable mechanism described in Patent Document 1 includes a focus group, a transmission member (feed screw) that converts the rotational driving force of the focus motor into a thrust force in the optical axis direction, and a biasing spring that biases the focus group toward the transmission member. In a state in which photography is possible, the focus group and the transmission member abut against each other and move together. In contrast, in a retracted state in which photography is restricted, the focus group is moved away from the transmission member against the biasing force, thereby narrowing the range of movement of the focus group.

[0004] Generally, focus motors are limited to controlling the relative drive amount. Therefore, drive control of the focus group requires a process for detecting the origin position (reset process). Therefore, Patent Document 1 is configured to include a light-shielding unit and an optical detection means, and detect the origin position by transitioning between a transmission state and a light-shielding state as the focus group moves. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4683795 Summary of the Invention [Problem to be solved by the invention]

[0006] However, for example, in the case of interchangeable lenses, Interchangeable lenses If power is suddenly interrupted, for example by mechanically removing the lens or by unplugging the battery that powers it, the focus group will remain in the position it was in when power was interrupted and will become undetectable. In this state where the current position of the focus group is uncertain, it is necessary to first execute the origin detection process for the focus group before starting shooting.

[0007] On the other hand, if a retractable mechanism that narrows the movement range of the focus group is adopted, as in Patent Document 1, the movement of the focus group is restricted, and the origin detection process cannot be executed until the transition to a state where image capture is possible is completed. In other words, when transitioning from a retracted state where image capture is restricted to a state where image capture is possible, the origin detection process for the focus group takes extra time, which may lead to a loss of image capture opportunities.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an optical device that is capable of detecting the origin, etc., even when the lens barrel is retracted. [Means for solving the problem]

[0009] In order to achieve the above object, an optical apparatus according to one aspect of the present invention includes a holding frame for holding an optical system, an intermediate member, a drive unit for moving the intermediate member in a direction along an optical axis of the optical system, a biasing member for biasing the holding frame relative to the intermediate member in a direction along the optical axis, and a detection unit for detecting the intermediate member, and is configured to take a first state in which a part of the holding frame is brought into contact with a part of the intermediate member in accordance with the biasing force of the biasing member, and a second state in which the holding frame is separated from the intermediate member against the biasing force of the biasing member, the second state is a state in which the optical system is in a retracted position and photography is restricted, and the first state transitions to the second state by the holding frame moving in a direction along the optical axis,In either the first state or the second state, the drive unit is capable of moving the intermediate member in a direction along the optical axis, and the detection unit is capable of detecting the intermediate member at least in the second state. [Effects of the Invention]

[0010] SUMMARY OF THE INVENTION An object of the present invention is to provide an optical device that is capable of detecting the origin, etc., even when the lens barrel is retracted. [Brief explanation of the drawings]

[0011] [Figure 1] 1A and 1B are front and rear perspective views of an interchangeable lens and a camera body according to an embodiment. [Figure 2] FIG. 1 is a block diagram showing the configuration of an interchangeable lens and a camera body according to an embodiment. [Figure 3] FIG. 1 is a cross-sectional view of an interchangeable lens (at the wide-angle end during shooting) according to an embodiment. [Figure 4] FIG. 1 is a cross-sectional view of an interchangeable lens (at the telephoto end during shooting) according to an embodiment. [Figure 5] FIG. 2 is a cross-sectional view of the interchangeable lens according to the embodiment (at the retracted end when not taking pictures). [Figure 6] 1A and 1B are a perspective view and an exploded perspective view of a collapsing mechanism according to an embodiment. [Figure 7] FIG. 2 is a front view of the collapsible mechanism according to the embodiment. [Figure 8] FIG. 2 is a cross-sectional view showing the telephoto end close-up state of the collapsible mechanism according to the embodiment. [Figure 9] FIG. 2 is a cross-sectional view showing the retracted end of the retractable mechanism according to the embodiment. [Figure 10] FIG. 10 is a perspective view showing a holding structure for a focus group at a telephoto end in an embodiment. [Figure 11] FIG. 2 is a perspective view showing a holding structure for a focus group at the retracted end in the embodiment. [Figure 12] FIG. 2 is a front perspective view of a lens mount according to an embodiment. [Figure 13] FIG. 10 is a cross-sectional view of the embodiment in which the focus group at the wide-angle end has been moved to the retracted end. [Figure 14] FIG. 10 is a cross-sectional view of the telephoto end focus group in the embodiment when moved to the retracted end. [Figure 15] 10 is a flowchart of an origin detection process according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals indicate the same or corresponding parts throughout the drawings. In this embodiment, an interchangeable lens will be described as an example of an optical device, but various modifications and changes can be made to other optical devices, such as an integrated lens camera, within the scope of the present invention.

[0013] <Example> FIG. 1 shows the appearance of an interchangeable lens (optical device) 101 according to this embodiment and a camera (hereinafter referred to as a camera body) 1 to which the interchangeable lens 101 is detachably attached. The camera body 1 is, for example, a digital camera. FIGS. 1A and 1B are perspective views showing the front side (subject side) and the back side (imaging surface side), respectively. In this embodiment, as shown in FIG. 1A, the optical axis direction, which is the direction in which the optical axis of the imaging optical system housed in the interchangeable lens 101 extends (the direction along the optical axis), is defined as the X-axis direction, and directions perpendicular to this are defined as the Z-axis direction (horizontal direction) and the Y-axis direction (vertical direction). Hereinafter, the Z-axis direction and the Y-axis direction will be collectively referred to as the Z / Y-axis direction. Furthermore, the rotation direction around the Z-axis will be defined as the pitch direction, and the rotation direction around the Y-axis will be defined as the yaw direction. The pitch direction and yaw direction (hereinafter collectively referred to as the pitch / yaw direction) are directions of rotation around two axes, the Z-axis and the Y-axis, which are perpendicular to each other.

[0014] 1, a grip section 2 is provided on the left side as viewed from the front (right side as viewed from the rear) for the user to hold the camera body 1 with their hand. A power operation section 3 is also provided on the top surface of the camera body 1. When the user turns on the power operation section 3 while the camera body 1 is in the power-off state, power is supplied, the camera body 1 enters the power-on state, and a computer program such as a process for detecting the origin of the focus group is executed, and the camera enters a shooting standby state.

[0015] Furthermore, even if the camera body 1 is in a power-off state, the camera system detects that the interchangeable lens 101 has been mechanically and electrically connected, starts supplying power to the interchangeable lens 101 from the camera body 1, and executes the origin detection process for the focus group. In this case, if the user turns off the power operation unit 3 while the camera body 1 is in a power-on state, the camera body 1 enters a power-off state.

[0016] Furthermore, the top surface of the camera body 1 is provided with a mode dial 4, a release button 5, and an accessory shoe 6. The user can switch between shooting modes by rotating the mode dial 4. The shooting modes include a manual still image shooting mode in which the user can freely set shooting conditions such as shutter speed and aperture value, an auto still image shooting mode in which the appropriate exposure is automatically obtained, and a video shooting mode for shooting videos. The user can also half-press the release button 5 to instruct shooting preparation operations such as autofocus and auto exposure control, and can fully press the button to instruct shooting. An accessory (camera accessory) such as an external flash or other lighting or light-emitting device can be detachably attached to the accessory shoe 6.

[0017] The interchangeable lens 101 includes a lens mount 102 that can be mechanically and electrically connected to a camera mount 7 provided on the camera body 1. The interchangeable lens 101 houses an imaging optical system that forms an image of a subject by focusing light from the subject. A zoom ring (operating member) 103 that can be rotated around the optical axis by a user is provided on the outer periphery of the interchangeable lens 101. When the zoom ring 103 is rotated by the user, the zoom groups that make up the imaging optical system move to predetermined usage positions that correspond to the angle of the zoom ring 103, within a range from the wide-angle end to the telephoto end. This allows the user to capture images at a desired angle of view. In this embodiment, as will be described in detail later, a retractable end is provided after the zoom ring 103 is rotated from the telephoto end to the wide-angle end, further limiting the scope of imaging. The retractable end is the position at which the interchangeable lens 101 is fully retracted.

[0018] As shown in FIG. 1B, the rear surface of the camera body 1 is provided with a rear operation unit 8 and a display unit 9. The rear operation unit 8 includes a plurality of buttons and dials assigned with various functions. When the camera body 1 is powered on and the still image or video shooting mode is set, the display unit 9 displays a through image of a subject captured by an image sensor (described later). The display unit 9 also displays shooting parameters indicating shooting conditions such as shutter speed and aperture value. The user can change the settings of the shooting parameters by operating the rear operation unit 8 while viewing the display. The rear operation unit 8 includes a playback button for instructing playback of a recorded captured image. When the user operates the playback button, the captured image is played back and displayed on the display unit 9. The display unit 9 may be a touch panel type having the same functions as the rear operation unit 8.

[0019] 2 is a block diagram showing the electrical and optical configurations of the interchangeable lens 101 and camera body 1. The camera body 1 has a power supply unit 10 that supplies power to the camera body 1 and interchangeable lens 101, and an operation unit 11 that includes the power operation unit 3, mode dial 4, release button 5, rear operation unit 8, and the touch panel function of the display unit 9. In this embodiment, the entire system of the camera body 1 and interchangeable lens 101 is controlled by a camera control unit 12 provided in the camera body 1 and a lens control unit 104 provided in the interchangeable lens 101 working in cooperation with each other. Note that the camera control unit 12 and the lens control unit 104 each have a built-in computer for controlling the camera body 1 and the interchangeable lens 101, respectively, and the entire system of the camera body 1 and the interchangeable lens 101 is controlled by operating the two in cooperation with each other.

[0020] The camera control unit 12 reads and executes a computer program stored in the storage unit 13. In doing so, the camera control unit 12 communicates various control signals, data, and the like with the lens control unit 104 via a communication terminal of an electrical contact 105 provided on the lens mount 102. The electrical contact 105 includes a power terminal that supplies power from the power supply unit 10 described above to the interchangeable lens 101.

[0021] The imaging optical system of the interchangeable lens 101 includes a zoom group 110 that is connected to the zoom operation ring 103 and moves in the optical axis direction to change the angle of view, and a lens vibration isolation group 112 that includes a shift lens as an image stabilization element. The lens vibration isolation group 112 reduces image blur by moving (shifting) in the Z / Y axis directions perpendicular to the optical axis. The imaging optical system also includes an aperture group 301 that adjusts the amount of light, and a focus group 114 that includes a focus lens that moves in the optical axis direction to perform focus adjustment. The interchangeable lens 101 also includes an image stabilization driver 201 that moves the lens vibration isolation group 112, an aperture driver 302 that drives the aperture group 301, and a focus driver 401 that moves the focus group 114.

[0022] The camera body 1 has a shutter unit 14, a shutter driver 15, an image sensor 16, an image processor 17, and the camera controller 12 described above. The shutter unit 14 controls the amount of light that is formed by the imaging optical system in the interchangeable lens 101 and that is exposed at the image sensor 16. The image sensor 16 photoelectrically converts the subject image formed by the imaging optical system and outputs an image signal. The image processor 17 performs various image processes on the image signal and then generates an image signal. The display 9 displays the image signal (through image) output from the image processor 17, displays the shooting parameters as described above, and plays back and displays captured images stored in the memory unit 13 or a recording medium (not shown).

[0023] The camera control unit 12 controls the focus driving unit 401 in response to a shooting preparation operation on the operation unit 11 (for example, half-pressing the release button 5, etc.). For example, when an autofocus operation is instructed, the focus detection unit 18 determines the focus state of the subject image formed on the image sensor 16 based on the image signal generated by the image processing unit 17, generates a focus signal, and sends it to the camera control unit 12. At the same time, the focus driving unit 401 sends information about the current position of the focus group 114 to the camera control unit 12. The camera control unit 12 compares the focus state of the subject image with the current position of the focus group 114, calculates a focus driving amount from the amount of deviation, and sends it to the lens control unit 104. The lens control unit 104 then moves the focus group 114 to a target position in the optical axis direction via the focus driving unit 401, thereby correcting the focus deviation of the subject image.

[0024] As will be described in more detail below, the focus drive unit 401 includes a focus motor 401a that functions as an actuator, and a photointerrupter 148 that detects the origin position of the focus group 114. In this embodiment, the photointerrupter 148 functions as a detector. Generally, a stepping motor, which is a type of actuator, is often used as the focus motor. However, because a stepping motor can only control the relative amount of drive, the current position of the focus group 114 becomes undefined when the camera body 1 is powered off. In this case, the current position of the focus group 114 cannot be detected.

[0025] Also, consider a case where the power to the camera body 1 remains on, but the power to the interchangeable lens 101 is interrupted by, for example, mechanically removing the interchangeable lens 101 from the camera mount 7 of the camera body 1. In this case, the focus group 114 is held in the position it was in when the power was interrupted, making it impossible to detect.

[0026] When the user turns on the power supply operation unit 3 while the current position of the focus group 114 is uncertain, the focus group 114 must first be moved to the origin position and origin detection processing must be executed before the camera enters a shooting standby state.

[0027] Note that focus motor 401a may be a DC motor with an encoder, an ultrasonic motor, a servo motor, etc. Also, photointerrupter 148 directly receives light emitted from a light-emitting unit with a light-receiving unit, but instead of this, a photoreflector that receives light reflected from a reflective surface, or a brush that comes into contact with a conductive pattern to electrically detect a signal may be used as the detection unit.

[0028] Furthermore, camera control unit 12 controls the driving of aperture group 301 and shutter unit 14 via aperture drive unit 302 and shutter drive unit 15 in accordance with the setting values ​​of aperture value and shutter speed received from operation unit 11. For example, when an automatic exposure control operation is instructed, camera control unit 12 receives a luminance signal generated by image processing unit 17 and performs photometric calculation. Based on the result of this photometric calculation, camera control unit 12 controls aperture drive unit 302 in accordance with a shooting instruction operation on operation unit 11 (such as a full press of release button 5). At the same time, camera control unit 12 controls the driving of shutter unit 14 via shutter drive unit 15 and performs exposure processing by image sensor 16.

[0029] The camera body 1 has a pitch shake detection unit 19 and a yaw shake detection unit 20 as shake detection means capable of detecting image shake caused by the user's hand shake, etc. The pitch shake detection unit 19 and the yaw shake detection unit 20 each use an angular velocity sensor (vibration gyro) and an angular acceleration sensor to detect image shake in the pitch direction (direction of rotation around the Z axis) and the yaw direction (direction of rotation around the Y axis), and output a shake signal.

[0030] The camera control unit 12 calculates the shift position of the lens vibration isolation group 112 in the Y-axis direction using the shake signal from the pitch shake detection unit 19. Similarly, the camera control unit 12 calculates the shift position of the lens vibration isolation group 112 in the Z-axis direction using the shake signal from the yaw shake detection unit 20. Then, the camera control unit 12 moves the lens vibration isolation group 112 to a target position in the Z-axis / Y-axis direction via the vibration isolation drive unit 201 in accordance with the calculated shift position in the pitch / yaw direction, thereby reducing image shake during exposure or when a through-image is displayed.

[0031] The interchangeable lens 101 has a zoom ring 103 for changing the angle of view of the imaging optical system, and a zoom detection unit 106 for detecting the angle of the zoom ring 103. The zoom detection unit 106 detects the angle of the zoom ring 103 operated by the user as an absolute value, and is configured using, for example, a resistive linear potentiometer. Information about the angle of view detected by the zoom detection unit 106 is sent to the lens control unit 104 and reflected in various controls by the camera control unit 12 described above. Meanwhile, some of this information is recorded together with the captured image in the storage unit 13 or a recording medium (not shown).

[0032] Next, the positional relationships of the main components of the interchangeable lens 101 will be described using Figures 3, 4, and 5. Figures 3, 4, and 5 are cross-sectional views on the XY plane including the optical axis, and the center line shown here substantially coincides with the optical axis determined by the imaging optical system, and therefore will be hereinafter referred to as the optical axis. Figure 3 shows the wide-angle end on the short focal length side of the zoom, and Figure 4 shows the telephoto end on the long focal length side of the zoom.

[0033] 3 and 4 both show the imaging optical system of the interchangeable lens 101 in a position where imaging is possible (a state where imaging is possible). On the other hand, Fig. 5 shows the imaging optical system of the interchangeable lens 101 in a stored state (a state where it is in a retracted position) when not taking images. Fig. 5 also shows the retracted end where the overall length in the optical axis direction is shortened to the shortest.

[0034] The retractable end shown in FIG. 5 is located further beyond the wide-angle end shown in FIG. 3 , and rotating the zoom operation ring 103 in one direction sequentially transitions from the retractable end shown in FIG. 5 to the wide-angle end shown in FIG. 3 , and from the wide-angle end shown in FIG. 3 to the telephoto end shown in FIG. 4 . In this embodiment, a state in which the imaging optical system is ready is referred to as a first state, and a state in which the imaging optical system is in a retracted position is referred to as a second state. Note that a state in which imaging is ready means that the functions of the camera, including the camera body 1 and the interchangeable lens 101, can operate normally at any time. Restricted imaging means that some of the functions of the camera, including the camera body 1 and the interchangeable lens 101, do not operate normally. For example, when the imaging optical system is in a retracted position, it is possible to take a photograph (e.g., pressing the shutter to capture a subject), but the captured image may be wholly or partially blurred due to factors such as being out of focus.

[0035] As shown in FIGS. 3 and 4 , this embodiment employs a six-group configuration as an example of an imaging optical system. The zoom group 110 moves to different predetermined usage positions at the wide-angle end and the telephoto end, respectively, and forms an image of light from a subject on the image sensor 16. The zoom group 110 is composed of a first zoom group 111, a lens vibration reduction group 112 functioning as a second zoom group, an aperture group 301, a third zoom group 113, a focus group 114 functioning as a fourth zoom group, a fifth zoom group 115, and a sixth zoom group 116. Note that this embodiment does not limit the configuration of the imaging optical system. For example, the lens vibration reduction group 112 and the focus group 114 may function as other zoom groups. Furthermore, some lens groups may be fixed rather than movable.

[0036] The linear guide barrel 107 is a fixed component that is fixed to the lens mount 102 via a fixed barrel (not shown). Cam grooves (not shown) are formed at equal intervals on the outer peripheral surface of the linear guide barrel 107. Meanwhile, cam followers (not shown) are provided on the inner peripheral side of the cam barrel 108. Furthermore, the cam barrel 108 is connected to the zoom operation ring 103 via a key (not shown). When the zoom operation ring 103 is rotated, the cam barrel 108 moves forward and backward in the optical axis direction while rotating about the optical axis due to the engagement between the cam grooves and the cam followers.

[0037] The linear guide barrel 107 has linear guide grooves formed at equal intervals that restrict movement of the zoom group 110 in the rotational direction and guide linear movement in the optical axis direction. Cam grooves, each with a different angle in the rotational direction, are formed at equal intervals in the cam barrel 108 to correspond to the zoom group 110. The zoom group 110 is provided with multiple cam followers, each of which is fitted into a corresponding linear guide groove and cam groove. When the user rotates the zoom operation ring 103, the cam barrel 108 rotates, and the cam followers, due to the fit between the linear guide grooves and the cam grooves, move the zoom group 110 forward and backward in the optical axis direction while restricting movement in the rotational direction.

[0038] The interchangeable lens 101 of this embodiment has a retractable mechanism, which will be described in detail later, and a retraction mechanism for the lens vibration isolation group (second zoom group) 112. This makes it possible to retract the zoom group 110 further to the rear side (image capture surface side) when not taking pictures. This makes it possible to shorten the overall length of the interchangeable lens 101, and improves the portability of the interchangeable lens 101 and the camera body 1.

[0039] At the wide-angle end shown in FIG. 3, the distance between the first zoom group 111 and the lens vibration reduction group (second zoom group) 112 is wide. Shown in At the telephoto end, the distance between the fifth zoom group 115 and the sixth zoom group 116 is wide. Zoom group 110The retractable mechanism moves the zoom groups 110 to a retracted position where they are close to each other, thereby shortening the overall length in the optical axis direction. As shown in Figure 5, at the retracted end when not shooting, the zoom groups 110 move to a retracted position where they are close to each other. From this state, for example, when the user rotates the zoom operation ring 103 to the wide-angle end, the zoom groups 110 extend to the front side (subject side) and move to a predetermined usage position, thereby reaching the state where shooting is possible, as shown in Figure 3.

[0040] Furthermore, during shooting as shown in FIGS. 3 and 4, all of the zoom groups 110 are arranged on the same optical axis, but at the retracted end when not shooting as shown in FIG. 5, the lens vibration reduction group (second zoom group) 112 retracts in a direction perpendicular to the optical axis (radial direction). When the user rotates the zoom operation ring 103 toward the retracted end from the wide-angle end where shooting is possible as shown in FIG. 3, the zoom group 110 begins to retract toward the rear side (image capture plane side), and at the same time, the lens vibration reduction group (second zoom group) 112 retracts from the optical axis. The first zoom group 111 further retracts into the space thus created and is stored so as not to interfere with each other, resulting in the state where the overall length is shortened to the shortest possible length as shown in FIG. 5. The retraction mechanism for the lens vibration reduction group (second zoom group) 112 is a well-known technology that has been adopted in many optical devices, so a detailed description is omitted.

[0041] Fig. 6(A) is a perspective view showing the retractable mechanism of this embodiment. Fig. 6(A) is a perspective view of the members (components) that make up the retractable mechanism of this embodiment, and Fig. 6(B) is an exploded perspective view showing some of the components shown in Fig. 6(A). Fig. 7 is a front view of the retractable mechanism of this embodiment, and Figs. 8 and 9 are cross-sectional views showing the S1-S1 cross section in Fig. 7. Fig. 8 shows the telephoto end of the interchangeable lens 101, the same as Fig. 4. Fig. 9 shows the retractable end of the interchangeable lens 101, the same as Fig. 5.

[0042] 6 to 9, the rear group base tube 118 houses a focus drive unit 401 having a focus motor 401a and a feed screw (meshing portion) 401b, a focus group holding frame 141 that holds the focus group 114, and the fifth zoom group 115. When zooming from the wide-angle end to the telephoto end, The retractable mechanism The rear group base cylinder 118 moves in the direction of the optical axis together with these components. Three cam followers 120 are provided at equally spaced positions on the outer periphery of the rear group base cylinder 118.

[0043] The cam followers 120 engage with tapered inner circumferential cam grooves provided on the inner periphery of the cam barrel 108, and the cam barrel engagement portions 120a of each cam follower 120 are conical and configured to contact (for example, make line contact with) the slope of the inner circumferential cam groove. Furthermore, the guide barrel engagement portions 120b of the cam followers 120 engage with linear guide grooves provided in the linear guide barrel 107. Rotating the zoom operation ring 103 rotates the cam barrel 108, which is connected by a key (not shown), and the rear group base barrel 118 moves in conjunction with the zoom operation ring 103. When the rear group base barrel 118 moves in this way in the optical axis direction, the system transitions from a first state in which photography is possible, as shown in FIG. 8, to a second state in which photography is restricted, as shown in FIG. 9, in which the movement of the focus group holding frame 141 is restricted.

[0044] 10 and 11 are perspective views showing the holding structure for the focus group 114. FIG. 10 shows the same telephoto end as FIGS. 4 and 8, and FIG. 11 shows the same retracted end as FIGS. 5 and 9. The first guide bar 142 is a metal member fixed to the rear group base tube 118, and engages with a slide hole 141a on the imaging surface side and a slide hole 141b on the subject side formed in the focus group holding frame 141. Similarly, the second guide bar 143 fixed to the rear group base tube 118 engages with a U-shaped groove 141c provided in the focus group holding frame 141. This holds the focus group holding frame 141 so that it can move freely in the optical axis direction relative to the rear group base tube 118.

[0045] In this embodiment, the rack holder (second intermediate member) 144 and the rack (first intermediate member) 146 are each configured as intermediate members. The rack holder 144 has a through hole into which the first guide bar 142 is inserted. The rack holder 144 is held so as to be freely movable in the axial direction of the first guide bar 142, and a boss 144a engages with an elongated hole 141d formed in the focus group holding frame 141, thereby preventing the rack holder 144 from rotating around the through hole. A compression coil spring (biasing member) 145 is disposed in the space between the focus group holding frame 141 and the rack holder 144. One end of the compression coil spring 145 biases the focus group holding frame 141 toward the imaging surface in the optical axis direction, and the other end similarly biases the rack holder 144 toward the slide hole 141b of the focus group holding frame 141 (the subject side).

[0046] The rack 146 meshes with the feed screw 401b of the focus drive unit 401, and the rotation shaft 146a engages with the fitting hole 144c of the rack holder 144, allowing rotation only around the fitting hole 144c. This allows the rotational driving force of the focus motor 401a to be stably converted into a propulsive force in the optical axis direction, even if the feed screw 401b vibrates due to variations in component precision. In addition, the rack 146 is fixed to the rack holder 144. Therefore, when the rack holder 144 moves in the optical axis direction, the rack 146 moves integrally (interlocked) in the same direction.

[0047] Figure 12 is a perspective view of the lens mount 102 as seen from the subject side. Figure 12 also shows the location of contact portion 102a that abuts against contact portion 141e of focus group holding frame 141 when the lens mount is retracted. At the telephoto end shown in Figure 10, the biasing force of compression coil spring 145 causes end portion 144b to abut against slide hole 141b on the subject side, and rack holder 144 and focus group holding frame 141 move together.

[0048] 11, the rear group base tube 118 moves in the optical axis direction toward the imaging surface, opposite the subject side, causing abutment portion 141e on the focus group holding frame 141 to abut against abutment portion 102a on the lens mount 102, which is a fixed member. As a result, the rack 146 meshes with the feed screw 401b and does not move, allowing the compression coil spring 145 to be compressed, thereby enabling the focus group holding frame 141 to move relative to the rear group base tube 118. At this time, the focus group holding frame 141 can be separated from the rack holder 144 against the biasing force of the compression coil spring 145. By separating the focus group holding frame 141 from the rack holder 144, the state transitions from the first state to the second state.

[0049] Next, detection of the origin position of the focus group holding frame 141 will be described with reference to Figures 13 and 14. Figure 13 is a cross-sectional view of the vicinity of the photointerrupter 148 when the focus group holding frame 141 enters a retracted state while remaining in the position at the wide-angle end shown in Figure 3. Figure 14 is a cross-sectional view of the focus group holding frame 141 enters a retracted state while remaining in the position at the telephoto end shown in Figures 4 and 8.

[0050] As shown in FIGS. 13 and 14 , the rack holder 144 is provided with a detection target 144d, and moving the rack holder 144 in the optical axis direction causes a transition between a light-transmitting state of the photointerrupter 148 and a light-blocking state caused by the detection target 144d. The photointerrupter 148 detects the light-transmitting state and the light-blocking state, outputs the signal as a reference signal, and transmits it to the lens control unit 104. Note that the photointerrupter 148 outputs a first signal as the reference signal in the light-blocking state and a second signal in the light-transmitting state. The lens control unit 104 then determines the position of the rack holder 144 as the origin position based on the received reference signal. Note that the photointerrupter 148 starts its detection operation when the interchangeable lens 101 is in a powered state.

[0051] As described above, the compression coil spring 145 is disposed between the focus group holding frame 141 and the rack holder 144, and biases the rack holder 144 in the optical axis direction relative to the focus group holding frame 141. Therefore, even when the focus group holding frame 141 is in a retracted state in which movement is restricted, driving the focus motor 401a allows the rack holder 144 to move toward the subject in the optical axis direction against the biasing force of the compression coil spring 145.

[0052] On the other hand, in a state where photography is possible, the contact portion 141e of the focus group holding frame 141 is separated from the contact portion 102a of the lens mount 102. Therefore, the biasing force of the compression coil spring 145 causes the contact portion 141e of the focus group holding frame 141 and the end portion 144b of the rack holder 144 to come into contact and adhere closely, and the focus group holding frame 141 and the rack holder 144 move together. In other words, if the position of the rack holder 144 can be detected, the position of the focus group holding frame 141 in a photography state can be identified. Thus, in this embodiment, the origin position of the focus group holding frame 141 can be detected via the rack holder 144 having the detection portion 144d, whether in a first state where photography is possible or a second state where photography is restricted and the lens barrel is retracted.

[0053] Next, the positional relationship between the photointerrupter 148 and the detected portion 144d of the rack holder 144 will be described with reference to Figures 13 and 14. The distance between the light-emitting portion 148a of the photointerrupter 148 and the detected portion 144d in the optical axis direction is longest toward the subject in the optical axis direction, as shown in Figure 13. On the other hand, the distance in Figure 14 is longest toward the imaging surface, as shown in Figure 14. In this embodiment, the positional relationship between A and B is approximately equal, that is, the position of the rack holder 144 determined by the lens control unit 104 is arranged to be approximately the center of the movement range of the rack holder 144. This prevents the detection time for the origin position from becoming extremely long, regardless of the zoom position or focus position conditions.

[0054] Fig. 15 shows a flowchart relating to the origin detection process of this embodiment. Each operation (process) shown in the flowchart of Fig. 15 is controlled by at least one of the camera control unit 12 and the lens control unit 104 executing a computer program. Note that Fig. 15 is an example of the origin detection process, and the present invention is not limited to this.

[0055] When power is supplied from the camera body 1 to the interchangeable lens 101, first in S101 the lens control unit 104 acquires information on the detection result of the photointerrupter 148, that is, acquires information on the signal output by the photointerrupter 148. At this time, the lens control unit 104 acquires information on whether the detection result of the photointerrupter 148 is light or dark. In this embodiment, if it is light, the photointerrupter 148 outputs a transparent State and judgment Decline, If the light is not emitted (dark), the photointerrupter 148 determines that the light is blocked and outputs the first signal.

[0056] If the detection result of the photointerrupter 148 is bright, the process proceeds to S102. If the detection result of the photointerrupter 148 is dark, the process proceeds to S106. Next, in S102, the lens control unit 104 controls the focus motor 401a of the focus drive unit 401 to move the rack holder 144 at high speed along the optical axis direction toward the imaging surface (camera body). The lens control unit 104 operates in response to instructions from the camera control unit 12. Then, the process proceeds to S103. The high speed here refers to the highest speed within the range in which the focus motor 401a does not lose synchronization between the rack 146 and the feed screw 401b (see speed 144e in FIG. 13). Note that in a retracted state in which photography is restricted, the detection result of the photointerrupter 148 becomes bright when the rack holder 144 and the photointerrupter 148 are in the positional relationship shown in FIG. 13.

[0057] Next, in S103, similar to S101, the lens control unit 104 acquires information on whether the detection result of the photointerrupter 148 is bright or dark. If the result is dark, the process proceeds to S104; if the result is bright, the process returns to S102. Next, in S104, the lens control unit 104 controls the focus motor 401a of the focus drive unit 401 to reverse the movement direction of the rack holder 144 and move it at a low speed along the optical axis toward the subject. Then, the process proceeds to S105. The "low speed" here refers to a speed at which the photointerrupter 148 can accurately detect the origin position of the detection target portion 144d (see speed 144f in FIG. 13). Next, in S105, similar to S101, the lens control unit 104 acquires information on whether the detection result of the photointerrupter 148 is bright or dark. If the result is bright, the detection of the origin position is completed. This completes the origin position detection process (reset process), and the process ends. If it was dark, S10 4 Return to.

[0058] Next, in S106, the lens control unit 104 controls the focus motor 401a of the focus drive unit 401 to move the rack holder 144 toward the subject at high speed along the optical axis. Then, the process proceeds to step S107. The "high speed" here has the same meaning as in S102 (see speed 144g in FIG. 14). In the retracted state in which photography is restricted, the detection result of the photointerrupter 148 becomes dark when the rack holder 144 and the photointerrupter 148 are in the positional relationship shown in FIG. 14. Thus, regardless of whether the camera is in the first state in which photography is possible or the second state in which photography is restricted, the camera control unit 12 controls the focus motor 401a to move the rack holder 144 based on the detection result (detected signal) of the photointerrupter 148. Therefore, even in the second state in which photography is restricted, the origin position detection process can be started immediately once the interchangeable lens 101 is energized.

[0059] Next, in S107, similarly to S101, the lens control unit 104 acquires information on whether the detection result of the photointerrupter 148 is light or dark, and if the result is light, the process proceeds to S108. If the result is dark, the process returns to step S106.

[0060] Next, in S108, similar to S102, the lens control unit 104 controls the focus motor 401a of the focus drive unit 401 to move the rack holder 144 at high speed along the optical axis direction toward the imaging surface. The "high speed" here has the same meaning as in S102 (see speed 144h in FIG. 14). Then, the process proceeds to step S109. Next, in S109, similar to S101, the lens control unit 104 obtains information on whether the detection result of the photointerrupter 148 is light or dark, and if the result is dark, the process proceeds to S110, and if the result is light, the process returns to step S108.

[0061] Next, in S110, similar to S104, the lens control unit 104 controls the focus motor 401a of the focus drive unit 401 to reverse the movement direction of the rack holder 144 and move it at a low speed along the optical axis toward the subject. The low speed here has the same meaning as explained in S104 (see speed 144i in FIG. 14). Then, the process proceeds to S111. Next, in S111, similar to S105, the lens control unit 104 acquires information on whether the detection result of the photointerrupter 148 is light or dark, and if it is light, the detection of the origin position is complete. This completes the detection process (reset process) of the origin position, and the process ends. If it is dark, the process returns to S110.

[0062] In this way, the direction in which the rack holder 144 moves along the optical axis changes depending on whether the detection result of the photointerrupter 148 is light or dark. That is, the lens control unit 104 controls the focus motor 401a of the focus drive unit 401 to change the driving direction in accordance with the detected signal. Then, whether in the first state or the second state, if the interchangeable lens 101 is in a powered state, the focus motor 401a of the focus drive unit 401 can be driven to move the rack holder 144 in any direction along the optical axis. Therefore, whether in the first state or the second state, the photointerrupter 148 can detect the detection target 144d provided on the rack holder 144.

[0063] Through the above processing, the origin position of the rack holder 144 is detected. After detecting the origin position of the rack holder 144, the lens control unit 104 controls the focus motor 401a of the focus drive unit 401 to move the rack holder 144 to the position before the origin position was detected or to a predetermined position (for example, the focus position at the wide-angle end). Furthermore, the photointerrupter 148 continues to detect the detection target portion 144d until the above processing is completed. After the processing is completed, the detection operation is stopped.

[0064] In this embodiment, light and dark are detected using the photointerrupter 148, but any threshold value, for example, High and Low (for example, the degree of brightness), may be used. Also, in order to detect the origin position more quickly, a plurality of photointerrupters 148 may be provided, and a plurality of detection target portions 144d may be provided on the rack holder 144.

[0065] According to this embodiment, even if the movement of the focus group 114 is restricted in the second state, which is a retracted state in which image capture is restricted, the origin position detection process can be executed via the rack holder 144. This makes it possible to reduce the time required before image capture begins, and it is possible to provide an interchangeable lens (optical device) 101 that is highly portable and reduces the loss of image capture opportunities.

[0066] Furthermore, in this embodiment, in order to enable accurate detection of the origin position, the rack holder 144 is moved toward the subject at a low speed when detecting the origin position, but this is not limiting, and the rack holder 144 may be moved at a high speed as long as the origin position can be accurately detected. Furthermore, as described above, the origin position detection method shown in Figures 13 and 14 is just one example, and the origin position may be detected by moving the rack holder 144 toward the imaging surface (camera body) at a low speed along the optical axis direction. That is, if the detection result is dark after power is supplied to the interchangeable lens 101, the rack holder 144 is moved toward the subject at a high speed along the optical axis direction, and then moved toward the imaging surface at a low speed along the optical axis direction to detect the origin position.

[0067] In this embodiment, the detected portion 144d is provided on the rack holder 144, but this is not limiting, and at least one detected portion 144d may be provided on the rack 146. Then, the same processing as above may be performed.

[0068] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0069] 1 camera body 101 Interchangeable Lenses 114 Focus Group 141 Focus Group Holding Frame 141a Sliding hole on the imaging surface side 141b Slide hole on the subject side 141c U-shaped groove 141d long hole 141e Contact part 142 First Guide Bar 143 Second Guide Bar 144 Rack Holder 144a Boss 144b End 144c Mating hole 144d Detected part 145 compression coil spring 146 racks 146a Rotating shaft

Claims

1. a holding frame for holding the optical system; An intermediate member; a drive unit that moves the intermediate member in a direction along the optical axis of the optical system; a biasing member that biases the holding frame relative to the intermediate member in a direction along the optical axis; a detection unit that detects the intermediate member, a first state in which a part of the holding frame abuts against a part of the intermediate member in accordance with the biasing force of the biasing member, and a second state in which the holding frame is separated from the intermediate member against the biasing force of the biasing member, The second state is a state in which the optical system is in a retracted position and photography is restricted, the holding frame moves in a direction along the optical axis, thereby transitioning from the first state to the second state; an optical device characterized in that, in either the first state or the second state, the drive unit is capable of moving the intermediate member in a direction along the optical axis, and at least in the second state, the detection unit is capable of detecting the intermediate member.

2. 2. The optical device according to claim 1, wherein the first state is a state in which the optical system is in a photographing position.

3. 3. The optical device according to claim 1, wherein the optical system includes a focus lens, and the drive unit is capable of adjusting focus by moving the focus lens in a direction along the optical axis.

4. The optical device according to any one of claims 1 to 3, characterized in that, when the optical device is in a powered state, the drive unit moves the intermediate member in a direction along the optical axis, thereby detecting the intermediate member with the detection unit.

5. 5. The optical device according to claim 1, wherein the biasing member is disposed between the holding frame and the intermediate member.

6. the detection unit outputs a first signal when the intermediate member is detected, and outputs a second signal different from the first signal when the intermediate member is not detected, 6. The optical device according to claim 1, further comprising a control unit that determines a position of the intermediate member based on the first signal and the second signal.

7. 7. The optical device according to claim 6, wherein the position of the intermediate member determined by the control unit is approximately the center of the movement range of the intermediate member.

8. a base cylinder that holds the holding frame movably in a direction along the optical axis, 8. The optical device according to claim 1, wherein the optical device transitions from the first state to the second state by moving the base tube in a direction along the optical axis.

9. a fixing member having an abutment portion that abuts against the holding frame, The optical device according to claim 8, characterized in that when the base tube moves in a direction along the optical axis toward the opposite side from the subject, the abutment portion moves the holding frame away from the intermediate member against the biasing force of the biasing member.

10. 10. The optical device according to claim 8, further comprising an operating member that is rotatable in a radial direction around the optical axis, and the base tube moves in a direction along the optical axis in conjunction with the rotation of the operating member.

11. the intermediate member includes a first intermediate member that meshes with a screw provided on the rotation shaft of the drive unit, and a second intermediate member that engages with the first intermediate member, 11. The optical device according to claim 1, wherein the second intermediate member moves in a direction along the optical axis in conjunction with the movement of the first intermediate member.

12. 12. The optical device according to claim 1, wherein the optical device is an interchangeable lens.

13. a camera body having a camera mount; A camera system comprising the optical device according to claim 1 , which is provided with a lens mount connectable to the camera mount.

Images