JP4784214B2 - Interchangeable lens for camera - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interchangeable lens for a camera, and more particularly to an interchangeable lens that can easily switch between lens driving by manual operation and electric lens driving.

  Patent Documents 1 and 2 describe interchangeable lenses that can easily switch between auto focus (hereinafter referred to as AF) and manual focus (hereinafter referred to as MF). The cited document 1 uses a small vibration wave motor as a focus motor, while the cited document 2 uses an annular large vibration wave motor. In any interchangeable lens, no special operation is required for switching between AF and MF, and MF is automatically performed only by starting the MF operation in the AF mode. The MF operation refers to an operation of rotating a manual operation ring provided on the peripheral surface of the lens barrel.

  In order to automatically switch between AF and MF as described above, it is necessary to always monitor the presence or absence of an MF operation and to quickly prohibit the rotation of the focus motor when an operation is detected. Patent Document 1 does not describe such an MF operation detection mechanism. On the other hand, Patent Document 2 describes an MF operation detection mechanism including a pattern portion provided in a manual operation ring and a detection portion fixed to a fixed cylinder.

  The MF operation detection mechanism in Patent Document 2 is generally composed of an annular glass epoxy substrate (pattern part) provided on a manual operation ring and a brush (detection part) in contact with the glass epoxy substrate. The glass epoxy substrate has a plurality of radial conduction patterns, and when the manual operation ring rotates, it is possible to detect that the manual operation ring has been operated by repeatedly turning on and off the switch composed of the pattern and the brush. Such an MF operation detection mechanism can also be applied to the lens barrel of Patent Document 1.

JP 2000-179635 A Japanese Patent Laid-Open No. 5-72463

  Since the manual operation ring is rotationally operated along the outer peripheral surface of the lens barrel, the diameter thereof is almost the same as the outer diameter of the lens barrel, and the glass epoxy fixed to the inner peripheral surface of the manual operation ring. It is necessary to use a substrate having a large diameter equivalent to that of the substrate. Since the glass epoxy substrate is generally formed by pressing, and particularly the inner diameter side is formed by punching, the larger the diameter, the larger the loss.

The present invention includes a manual operation ring that can be rotated around an optical axis, a first power transmission mechanism that transmits rotation of the manual operation ring to a lens driving member, and an operation detection unit that detects an operation of the manual operation ring, A camera replacement having a second power transmission mechanism for transmitting the driving force of the motor to the lens driving member, and a control unit for stopping the rotation of the motor when the operation detecting means detects the operation of the manual operation ring. Applied to the lens.
According to the first aspect of the present invention, the first power transmission mechanism has a clutch mechanism for allowing the manual operation ring to idle even after the lens reaches the driving end and is prevented from moving, and the operation detecting means Is a pattern portion formed on a rotating member provided between the manual operation ring and the clutch mechanism in the power transmission path of the first power transmission mechanism, and a signal corresponding to the presence or absence of rotation of the pattern portion. Signal output means for outputting.
In the invention of claim 2, the first power transmission mechanism has a connecting gear that meshes with a gear provided in the manual operation ring,
The operation detection unit includes a pattern portion formed on a rotating member that rotates integrally with the connection gear, and a signal output unit that outputs a signal corresponding to the presence or absence of rotation of the pattern portion.

  According to the present invention, since the pattern portion for detecting the operation of the manual operation ring is provided in the power transmission mechanism that transmits the operation force of the manual operation ring, not the manual operation ring itself, the pattern portion can be reduced in size. Costs can be reduced by minimizing losses during manufacturing.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a cross-sectional view showing a focus drive mechanism in an interchangeable lens barrel, and FIGS. 2 and 3 are views seen from directions A and B in FIG. 1, respectively. The focus drive mechanism is roughly divided into an MF transmission mechanism 10, a friction gear mechanism 20, a lens drive mechanism 30, and an AF motor transmission mechanism 40 from the right side of FIG. The driving forces of MF and AF are transmitted to the lens driving mechanism 30, and a focus optical system (not shown) is moved in the optical axis direction via the lens driving mechanism 30. An MF operation detection mechanism 50 that detects the presence or absence of operation of a manual operation ring (not shown) is provided in the MF transmission mechanism 10.

Details of each part will be described below.
<MF transmission mechanism, MF operation detection mechanism>
The manual operation ring can be rotated around the optical axis along the outer peripheral surface of the lens barrel, and a gear formed on the inner peripheral surface meshes with the MF connecting gear 11. The MF connecting gear 11 is non-rotatably attached to the shaft member 12, and the shaft member 12 is rotatably supported by the gear upper plate 1 and the gear base plate 2. A flange 12a is formed in the lower part of the shaft member 12 in the figure, and a glass epoxy substrate 51 constituting the MF operation detection mechanism 50 is fixed to the flange 12a. Therefore, when a manual operation ring rotation operation (MF operation) is performed, the MF connection gear 11, the shaft member 12, and the glass epoxy substrate 51 rotate together.

  The glass epoxy substrate 51 has a disk shape having substantially the same diameter as the flange 12a, and is affixed to the flange 12a with a double-sided tape. In the pattern formed on the surface of the substrate 51, as shown in FIG. 2, the rotation center side is a full conduction pattern 51a and the outside is a radial pattern 51b. The brush 52 attached to the motor upper plate 1 is in contact with the patterns 51a and 51b, respectively, and a switch signal composed of the brush 52 and the patterns 51a and 51b is input to a control unit (not shown). When the substrate 51 rotates, the switch ON signal and the OFF signal are alternately input, so that the control unit can recognize that the manual operation ring has been rotated.

The clutch gear 14 rotatably supported by the shaft member 12 meshes with the friction gear 21, and is provided with a spring 15 provided between the flange 12 a and a MF connection gear 11 via a washer 16 interlocked with the MF connection gear 11. Pressed against. Normally, the clutch gear 14 rotates integrally with the MF coupling gear 11 and transmits the rotation to the friction gear 21. However, when the rotational load of the friction gear 21 exceeds a predetermined value, the clutch gear 14 remains stationary and the MF coupling gear. 11 and the shaft member 12 rotate. By providing this clutch gear 14, even if the focus optical system reaches either the close side or the infinity side and is prevented from moving, the manual operation ring is allowed to rotate (idle). It is possible to prevent the breakage without applying excessive force.
Reference numeral 17 denotes an E-type retaining ring for fastening the parts on the shaft member 12 described above.

<Friction gear mechanism>
The friction gear 21 has a spring sliding portion 21 a and is rotatably supported on the gear upper plate 1 while being pressed against the friction spring 22. In order to rotate the friction gear 21, a torque sufficient to overcome the torque generated by the spring force of the friction spring 22 is required, and an appropriate operation ring is operated by operating the manual operation ring with a force sufficient to generate the torque. Giving.

<Lens drive mechanism>
The friction gear 21 meshes with an MF input gear 32 that is non-rotatably attached to the shaft member 31. The shaft member 31 is rotatably supported by the gear upper plate 1 and the gear base plate 2, and a sun gear 31a is integrally formed on the upper portion thereof. The rotation of the friction gear 21 rotates the shaft member 31 via the MF input gear 32, and the sun gear 31a rotates accordingly.

  Reference numeral 33 denotes a gear member rotatably supported by the shaft member 31, and has an outer gear 33a and an inner gear 33b on the outer peripheral surface and the inner peripheral surface, respectively. The inner gear 33a is positioned so as to surround the sun gear 31a. A carrier gear 34 that transmits power to the focus optical system is rotatably supported on the shaft member 31, and a plurality of planetary gears 35 that are rotatably supported on the carrier gear 34 include a sun gear 31a and an inner gear 33a. Are engaged. The plurality of planetary gears 35 are arranged at an equal distance from the rotation axis of the carrier gear 34 (the rotation center of the shaft member 31), and the planetary gear 35 revolves around the rotation axis of the carrier gear, whereby the carrier gear 34 is Rotate. Reference numeral 36 denotes a washer for retaining the planetary gear 35.

<AF motor transmission mechanism>
The focus motor 41 is a small vibration wave motor that rotates about an axis parallel to the lens optical axis, and a gear 42 provided on the output shaft thereof meshes with the outer gear 33 a of the gear member 33. A drive signal is input to the motor 41 via the wiring member 43 (FIGS. 2 and 3).

  In the above configuration, when an AF start operation is performed in the AF mode, the control unit of the camera drives the focus motor 41 to perform the AF operation. The rotation of the motor 41 rotates the gear member 33 via the gear 42 and the outer gear 33a, and accordingly, the plurality of planetary gears 35 rotate. On the other hand, since the shaft member 31 is locked by the meshing of the friction gear 21 and the MF input gear 32 (the torque for rotating the friction gear 21 is not transmitted), the sun gear 31a does not rotate. Therefore, the planetary gear 35 revolves around the central axis of the shaft member 31 while rotating, and the revolution rotates the carrier gear 34. As the carrier gear 34 rotates, a focus optical system (not shown) moves in the optical axis direction (AF is performed). At this time, since the friction gear 21 does not rotate, the MF transmission mechanism 10 and the manual operation ring do not rotate.

  When an MF operation (manual operation ring operation) is performed without switching to the MF mode, the rotation detection mechanism 50 described above detects the rotation, and the control unit stops the focus motor 41. The rotational force of the manual operation ring rotates the friction gear 21 via the clutch gear 14 and rotates the shaft member 31, that is, the sun gear 31 a via the gear 32. On the other hand, since the gear member 33 is locked by the gear 42, it does not rotate, and the planetary gear 35 revolves around the central axis of the shaft member 31 while rotating. As a result, the carrier gear 34 rotates in the same manner as described above, and the focus optical system is driven (MF is performed). In order to perform AF after the MF operation is completed, it is only necessary to perform an AF start operation.

  As described above, in the present embodiment, the glass epoxy substrate 41 for detecting the MF operation is integrally provided on the gear shaft interlocked with the manual operation ring, not the manual operation ring. Therefore, it is not necessary to use a large-diameter annular glass epoxy substrate that is fixed to the manual operation ring, and a small-diameter disk-shaped glass epoxy substrate is sufficient, so that loss in the manufacturing process can be reduced and costs can be reduced.

  By the way, as described above, the manual operation ring can be idled by the action of the clutch gear 14 even when the focus optical system reaches the drive end. On the other hand, since the rotation of the manual operation ring needs to be detected regardless of the state of the clutch (connected / disconnected), the glass epoxy substrate 51 needs to be provided before the clutch gear 14 in the power transmission path. If the glass epoxy substrate 51 is provided after the clutch gear 41, the rotation is not detected when the manual operation ring is idle, and the focus motor may be driven even when the MF operation is continued. . For example, it is assumed that the MF operation in the closest direction is continued even after the focus optical system reaches the closest position that is the driving end. At this time, if the motor is driven in the reverse direction, the focus optical system moves to the infinity side opposite to the MF operation direction, and the photographer has great distrust. In the present embodiment, since the glass epoxy substrate 51 is attached to a member integral with the shaft member 12, that is, the front stage of the clutch gear 14, the above inconvenience cannot occur.

  In the MF transmission mechanism 10, when there are a plurality of rotating members (gears, gear shafts, etc.) in the preceding stage of the clutch gear, any of the rotating members may be provided with a glass epoxy substrate. However, the detection accuracy is higher when the rotating member is provided as close to the manual operation ring as possible. In the example of FIG. 1, since the glass epoxy substrate is provided on the rotating member at the next stage of the manual operation ring, the accuracy is highest. In addition, the clutch is not an essential requirement of the invention, and when there is no clutch, a glass epoxy substrate may be provided on any of the rotating members interlocked with the operation of the manual operation ring. If the clutch gear 14 is eliminated in the example of FIG. 1, a glass epoxy board may be provided on the gear 21 or the shaft member 31. Further, the focus drive mechanism has been described. However, the present invention can be applied to a zoom drive mechanism as long as it is an interchangeable lens capable of manual and electric zoom.

Sectional drawing which shows the focus drive mechanism of the interchangeable lens in one Embodiment. The figure seen from the A direction of FIG. The figure seen from the B direction of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 MF transmission mechanism 11 MF connection gear 12 Shaft member 14 Clutch gear 20 Friction gear mechanism 30 Lens drive mechanism 40 AF motor transmission mechanism 41 Motor 50 MF operation detection mechanism 51 Glass epoxy board 52 Brush

Claims (7)

A manual operation ring that can be rotated around the optical axis, a first power transmission mechanism that transmits the rotation of the manual operation ring to the lens driving member, an operation detection means that detects the operation of the manual operation ring, and a motor A camera comprising: a second power transmission mechanism that transmits a driving force to the lens driving member; and a control unit that stops the rotation of the motor when an operation of the manual operation ring is detected by the operation detection unit. For interchangeable lenses,
The first power transmission mechanism has a clutch mechanism for allowing the manual operation ring to idle even after the lens reaches the driving end and its movement is blocked,
The operation detecting means includes a pattern portion formed on a rotating member provided between the manual operation ring and the clutch mechanism in the power transmission path of the first power transmission mechanism, and rotation of the pattern portion. An interchangeable lens for a camera, comprising: signal output means for outputting a signal according to presence or absence. A manual operation ring that can be rotated around the optical axis, a first power transmission mechanism that transmits the rotation of the manual operation ring to the lens driving member, an operation detection means that detects the operation of the manual operation ring, and a motor A camera comprising: a second power transmission mechanism that transmits a driving force to the lens driving member; and a control unit that stops the rotation of the motor when an operation of the manual operation ring is detected by the operation detection unit. For interchangeable lenses,
The first power transmission mechanism has a connection gear that meshes with a gear provided in the manual operation ring,
The operation detection means includes a pattern portion formed on a rotating member that rotates integrally with the connection gear, and a signal output means that outputs a signal corresponding to the presence or absence of rotation of the pattern portion. interchangeable camera lens. The said 1st power transmission mechanism has a power interruption member which blocks | prevents that the driving force from the said 2nd power transmission mechanism transmits to the said manual operation ring, The Claim 1 or 2 characterized by the above-mentioned. Interchangeable lens for camera. 4. The interchangeable lens for a camera according to claim 3 , wherein the operation detecting means is provided on the manual operation ring side with respect to the power cut-off member . The first power transmission mechanism includes a connection gear that meshes with a gear provided in the manual operation ring, and the clutch mechanism includes a clutch gear that can rotate integrally with the connection gear. Item 4. The interchangeable lens for camera according to Item 1 . 6. The interchangeable lens for a camera according to claim 1, wherein the control unit recognizes that the manual operation ring has been operated by the signal from the signal output unit . The interchangeable lens for a camera according to claim 1, wherein the motor is a vibration wave motor .

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