JP2008058914A - Camera with zoom function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera with a zoom function capable of performing motor-driven operation and manual operation without changing the position of a hand to perform zooming operation. <P>SOLUTION: The camera with the zoom function is provided with: a zoom operation ring 25 where a ring gear 25a for manual zoom is formed; a motor 31 for motor-driven zoom; and a switching member 35 selecting either the manual operation or the motor-driven operation. It is equipped with a selection gear 27 always meshed with a cam barrel gear 23a formed integrally with a cam barrel 23 and selecting either a motor gear 31a or the ring gear 25a to be meshed therewith. The switching member 35 holds the selection gear 27 and a detection member 36 by a holding part 35a. The detection member 36 is equipped with pressure sensors 37 and 38. The detection member 36 abuts on a projecting part 25b provided on the zoom operation ring 25 so as to hold a pressing member 39 for transmitting the rotational force of the zoom operation ring 25 to the pressure sensors 37 and 38 to freely rock. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lens driving device, and more particularly, to a camera with a zoom function that enables zooming of a zoom lens to be operated manually or electrically.

  In an imaging device such as a digital camera equipped with a zoom lens barrel that can shoot while changing the size of the subject, there is a lens driving method for zooming that changes the size of the shooting by changing the focal length of the lens. The zoom lens is mounted on the lens barrel, and a part of the zoom lens is exposed to the exterior surface so that it can be rotated freely. There is a method of changing the focal length of a lens by rotating a cam cylinder arranged on the outer periphery.

  Among these, the one with a built-in motor has a lens driving unit attached to the lens barrel, and a zoom lens mirror with both a motor-driven lens driving device and a zoom operation ring for manual operation. There is a camera with a torso or zoom function. Such a lens barrel capable of driving the lens both manually and electrically is provided with a zoom operation ring for manual operation and a zoom operation button for operation, and further switching for selecting these modes. A member is provided.

  Here, it is troublesome to switch between manual and electric in lens operation with a switching member, and when manual operation is performed following electric operation, it is detected that the zoom ring for manual operation has been operated, and the motor is forced. A method for stopping the operation and switching to manual operation is shown in Patent Document 1 below.

Patent Document 2 below discloses a method of manually rotating an operation ring provided with a plurality of sensors for detecting a rotation angle and a rotation speed to change the rotation speed of the power zoom. This method retains the manual operation feature of rotating the operation ring and allows the operation speed to be freely changed. In addition to this, a method for detecting the time during which the push button is pressed is also disclosed.
JP 2000-221383 A Japanese Patent Laid-Open No. 06-160693

  In each of the above conventional examples, it is desired to smoothly perform zooming quickly or make fine adjustments slowly. However, in the method of the above-mentioned Patent Document 1, the position of the operation member must be changed between the electric operation for motor driving and the manual operation for fine adjustment, and the position of the hand for the operation must be changed. Considering the stability of framing, it is not preferable.

  The zooming operation method disclosed in Patent Document 2 is the same as increasing the rotation of the zoom ring. In high-speed zooming, it is slower than the method of simply pressing a button. There is a problem that the reaction is slower than the operation. Needless to say, the method of pressing a push button does not allow delicate control as in the case of the above-described operation by hand.

  In view of the above problems, the present invention makes it possible to selectively switch between a method for adjusting the focal length of a photographic lens using a motor that performs zooming at a high speed and a constant speed and a method using a manual operation ring that allows fine adjustment by hand touch. Furthermore, another object of the present invention is to provide a camera with a zoom function that can maintain stable framing without changing the operation member for zooming even when the two methods are switched.

  A zoom operation ring which is partially exposed to the exterior surface and can be rotated freely so that the zoom lens whose focal length is changed by rotating the cam cylinder can be driven manually or electrically, and the cam A motor that applies a rotational force to the cylinder; and a switching unit that selects either manual operation or electric operation.

  A cam cylinder gear is formed integrally with the cam cylinder, a motor gear is provided on the rotating shaft of the motor, and a ring gear is provided inside the zoom operation ring. A selection gear that is always coupled to the cam barrel gear and selects and meshes either the motor gear or the ring gear. A switch for turning on / off the power supply to the motor is also provided.

  A pressure sensor that receives the rotational force of the zoom operation ring, converts the rotational force into an electrical signal, and outputs the electrical signal; and an engagement position where the pressure sensor contacts a convex portion formed integrally with the zoom operation ring; A detection member is provided that is movable between a deviation position where the pressure sensor does not contact the convex portion.

  A switching member is provided that holds the selection gear and the detection member and is movable between a first operation position where the switch is turned on and a second operation position where the switch is turned off by an integrally formed switch pressing portion. In the first operation position, the selection gear meshes with the motor gear, and the detection member becomes the engagement position. When the switch is turned off at the second operation position, the selected gear meshes with the ring gear, and the detection member becomes the disengaged position.

  According to the present invention, the focal length adjustment of the photographing lens can be zoomed at a high speed and at a constant speed by the motor, and the fine adjustment by the hand feeling is continuously performed without separating the hand for adjusting the zooming speed from the operation member. Since it is possible to switch to manual operation that can be adjusted, it is possible to continue shooting framing stably.

  Preferred embodiments of a camera with a zoom function according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective external view of the camera 10, and FIG. 2 shows a configuration of the lens barrel 12.

  At least one of the plurality of lens groups constituting the zoom lens 16 is a moving lens, and a pin 18a embedded in the lens tube 18 of the moving lens engages with a cam groove provided on the inner wall of the cam tube 23, So-called zooming is performed in which the focal length of the photographic lens is changed by moving the moving lens in the optical axis direction by rotation of the cam barrel 23 and changing the distance from other lenses.

  The switching member 35 provided in the zoom lens barrel 12 holds the selection gear 27 and the detection member 36 by a holding portion 35a, and a first operation position that is an electric zoom position by a motor and a second operation position that is a manual operation position. It is possible to move between. FIG. 3 shows the relationship of gears when the switching member 35 is in the second operation position and manual zooming is performed. The detection member 36 is at a disengagement position where it does not engage with the convex portion 25 b provided on the zoom operation ring 25. The switching member 35 is provided with a switch pressing portion 35c. A detection member 36 including a selection gear 27 and pressure sensors 37 and 38 is attached by a holding portion 35 a of the switching member 35, and the position of the selection gear 27 can be changed by the switching member 35.

  The selection gear 27 is in a position where it engages with a ring gear 25 a formed integrally with the zoom operation ring 25. At this time, even if the position of the selection gear 27 is changed by the switching member 35, the selection gear 27 is always meshed with the cam cylinder gear 23a formed integrally with the cam cylinder 23, so that the zoom operation ring 25 is rotated. And the selection gear 27 rotates to rotate the cam cylinder gear 23a. As a result, when the cam cylinder 23 rotates, the lens cylinder moves back and forth, and zooming of the taking lens is performed.

  Next, the state when the switching member 35 is set to the first operation position is shown in FIGS. The switch pressing portion 35c provided on the switching member 35 turns on the switch 33 by moving the switching member 35 from the second operation position to the first operation position. As a result, the power supply of the drive circuit of the motor 31 is turned on. The position of the selection gear 27 is changed by the switching member 35, the meshing with the ring gear 25a is released and the motor gear 31a is meshed.

  A pressing member 39 provided on the detection member 36 so as to be slightly swingable is in an engagement position where it abuts on a convex portion 25 b provided on the zoom operation ring 25, and the zoom operation ring 25 swings the pressing member 39. Prevents moving beyond the range. Here, when the zoom operation ring 25 is rotated in the direction of the arrow (see FIG. 4), the convex portion 25b presses the pressing member 39 and presses the pressing member 39 against the pressure sensor 27 provided on the detection member 36. The rotational force applied to the zoom operation ring 25 is transmitted to the pressure sensor 27, and the pressure sensor 27 outputs an electrical signal having a magnitude corresponding to the rotational force. A current corresponding to the magnitude of the electrical signal output from the pressure sensor flows into the motor 31 and the motor 31 rotates. The rotation of the motor 31 is transmitted to the cam barrel gear 25a through the motor gear 31a and the selection gear 27, and the cam barrel 25 is rotated. As a result, the photographing lens changes in the direction in which the focal length becomes longer.

  Next, when the zoom operation ring 25 is turned in the direction of the arrow shown in FIG. 5, the convex portion 25 b presses the pressing member 39 to press the pressing member 39 against the pressure sensor 28 provided on the detection member 36. The rotational force applied to the zoom operation ring 25 is transmitted to the pressure sensor 28, and the pressure sensor 28 outputs an electrical signal having a magnitude corresponding to the rotational force.

  The output of the pressure sensor 28 causes the motor 31 to rotate in the direction opposite to that when the pressure sensor 27 outputs. As a result, the photographing lens changes in a direction in which the focal length becomes shorter. At this time, the relationship between the pressure applied to the pressure sensor and the zooming speed of the photographing lens may be a linear relationship such as (a) shown in FIG. It may be as shown in (b).

  For the pressure sensors 37 and 38, piezoelectric elements such as piezoelectric ceramics and piezoelectric films are used. Alternatively, a piezoresistive semiconductor pressure sensor, a quartz pressure sensor, a capacitive pressure sensor, or the like may be used.

  The focal length that changes due to zooming is always detected and monitored by a position detection device (not shown) provided on the cam barrel 23, and is displayed on the lens barrel overview portion with liquid crystal or electronic paper as shown in FIG. It is good to display in the same way on the display panel and viewfinder on the back side of the camera. Furthermore, the focal length to be displayed is always corrected by receiving information from the camera body to display the value converted to 35 mm film size so that it is not affected by the size of the image sensor provided in the camera body. It is good to display the value which was done.

  Here, the photographing procedure of the camera according to the present invention will be described with reference to the flowchart shown in FIG. When the power switch of the camera is turned on, it is determined whether it is electric or manual by a microcomputer program in the camera. Here, when the switching member 35 is in the first operation position, the switch 33 is turned on, and the zoom operation ring 25 is substantially locked in rotation by the pressing member 39. The selection gear 27 meshes with the motor gear 31a, and the rotation of the motor 31 is transmitted to the cam cylinder gear 23a, and the cam cylinder 23 is rotated.

  In a state where no rotational force is applied to the zoom operation ring 25, the outputs of the pressure sensors 37 and 38 are both 0, so the motor 31 does not rotate. When a rotational force is applied to the zoom operation ring 25, the pressure sensor 37 or 38 outputs an electric signal having a magnitude corresponding to the rotational force, and the motor 31 rotates. The motor 31 rotates to zoom the photographing lens. The taking lens zooms as long as the output of the pressure sensor 37 or 38 is present, but when the lens is at the maximum telephoto position (T end) or the widest angle position (W end), it stops and waits for the next instruction.

  When the photographer wants to finely adjust the framing of the subject by manual zooming, the switching member 35 is moved to the second operation position. At this time, since the switching member 35 is disposed near the zoom operation ring 25 (see FIG. 1), for example, it is only necessary to move the thumb a little. Then, the switch 33 of the motor 31 is turned off, and the pressing member 39 is separated from the convex portion 25b and unlocks the rotation of the zoom operation ring 25. The selection gear 27 is disengaged from the motor gear 31a and is engaged with the ring gear 25a. Accordingly, the cam cylinder 23 is rotated by rotating the zoom operation ring 25, and fine zooming by touch of the hand can be performed.

  When the shooting composition is determined, when the shutter button is pressed, the aperture / shutter speed / lens focus position is determined by AE / AF, then shooting is performed, and the subject image is recorded.

  Here, in the above-described embodiment, the rotational force of the zoom operation ring is received by the pressure sensor and converted into an electric signal to control the rotation of the motor. However, an angle sensor may be used instead of the pressure sensor. As an angle sensor, a method of detecting the rotation angle by providing a brush on the zoom operation ring and making it contact with a zebra pattern fixed in the lens barrel, or detecting a zebra pattern provided on the zoom operation ring with a photocoupler. A detection method may be used. Alternatively, other encoders may be used.

  As described above, according to the camera with a zoom function according to the present invention, the method of adjusting the focal length of the photographing lens is a method using a motor that performs stable zooming at a high speed and a constant speed, and a manual operation that allows fine adjustment by hand touch To provide a camera with a zoom function capable of maintaining stable framing because it is possible to selectively switch both methods using a ring and there is no need to change the operation member for zooming even when the two methods are switched. Can do.

  In addition, although the switching operation between the electric operation and the manual operation is performed by the switching member 35, it may be used for the selection switching between still image shooting and moving image shooting. In this case, an electric zooming operation may be performed during moving image shooting, and a manual zooming operation may be performed during still image shooting. Further, optical zoom and electronic zoom may be combined. When taking a still image, it is preferable to perform a manual zooming operation using only the optical zoom, and when shooting a moving image, use an optical zoom and an electronic zoom to increase the shooting magnification and to perform an electric zooming operation.

  FIG. 9 and FIG. 10 show changes in the focal length of the taking lens when a still image is taken with only an optical zoom for manual operation and when moving images are taken with an optical zoom plus an electronic zoom. During still image shooting, the focal length of the optical zoom lens changes from the W end (24 mm) to the T end (200 mm) as the cam barrel rotates. During movie shooting, the optical zoom lens changes (see Fig. 10 (a)) and the electronic zoom magnification also changes from the W end (x1) to the T end (x2) (see Fig. 10 (b)). As a result, the apparent focal length continuously changes from the W end (24 mm) to the T end (400 mm) (see FIG. 10C).

  Even when switching between still images and moving images as described above, it is not necessary to change the camera, and still images and moving images can be switched at any time while maintaining the same framing. As described above, the contents of the present invention can be applied in various ways, and it is expected that the possibility of use will be further expanded by combination with known techniques.

1 is a perspective external view of a camera with a zoom function according to an embodiment of the present invention. 1 is a structural diagram of a zoom lens barrel. The figure which shows the relationship of the gear at the time of manual zoom selection. The figure which shows the relationship of the gear at the time of zooming to the T side by electric zoom. The figure which shows the relationship of the gear at the time of zooming to the W side by electric zoom. The graph showing the relationship between the pressure applied to the pressure sensor and the zooming speed of the photographic lens. The figure which looked at the zoom lens barrel from the top. The flowchart of the imaging | photography procedure of the camera with a zoom function which is embodiment by this invention. The graph which shows the change of the focal distance at the time of still image photography. The graph which shows the change of the focal distance at the time of video recording.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Camera 12 Zoom lens barrel 23 Cam cylinder 23a Cam cylinder gear 25 Zoom operation ring 25a Ring gear 25b Convex part 27 Selection gear 31 Motor 31a Motor gear 35 Switching member 35a Holding part 36 Detection member 37, 38 Pressure sensor 39 Press member

Claims (5)

A zoom lens comprising a plurality of lenses including at least one moving lens is incorporated, and has a cam cylinder that engages with the lens cylinder of the moving lens via a cam mechanism, and the cam lens rotates to light the moving lens. In a camera with a zoom function that changes the focal length by moving it in the axial direction and changing the distance to other lenses,
A motor for applying a rotational force to the cam cylinder;
A zoom operation ring that is rotatably arranged on the outer periphery of the lens barrel and rotates the cam barrel in accordance with the operation amount;
A sensor that converts the rotation of the zoom operation ring into an electrical signal and outputs the electrical signal;
One of a manual zoom position in which the rotation of the zoom operation ring is transmitted to the cam cylinder and the cam cylinder is rotated, and an electric zoom position in which the motor is rotated by the output of the sensor and the cam cylinder is rotated are selected. A camera with a zoom function, characterized by comprising switching means. The switching means is
A selection gear that is always meshed with a cam barrel gear formed integrally with the cam barrel and selectively meshed with any one of the ring gear and the motor gear integrally formed inside the zoom operation ring;
A detection member movable between an engagement position for transmitting rotation of the zoom operation ring to the sensor and a separation position where the sensor does not receive rotation of the zoom operation ring;
A switch for turning on / off the power supply to the motor;
When the switch is turned on by an integrally formed switch pressing portion, the selection gear meshes with a motor gear that outputs rotation of the motor, and the detection member becomes the engagement position, and the switch is 2. The switch gear according to claim 1, further comprising a switching member that is movable between a second operation position where the selection gear meshes with the ring gear and the detection member becomes the separation position when the gear is turned off. Camera with zoom function.   3. The camera with a zoom function according to claim 1, wherein the sensor is an angle sensor that converts a rotation amount of the zoom operation ring into an electric signal and outputs the electric signal.   The camera with a zoom function according to claim 1, wherein the sensor is a pressure sensor that outputs an electric signal in response to a rotational force of the zoom operation ring.   The camera with a zoom function according to claim 4, wherein the pressure sensor is a piezoelectric element.

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