JP2006039372A - Lens barrel and optical equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a smaller lens barrel and an optical device.
Drive means comprising a coil and a magnet, wherein the coil or magnet is integrally formed with a holding member that holds an optical element, and is driven in a lens barrel that drives the holding member in the optical axis direction. The projected shape in the optical axis direction of the means is formed into a fan shape having the optical axis as the center.
[Selection] Figure 1

Description

  The present invention relates to a lens barrel that performs operations such as focusing and zooming by driving a lens group in an optical system in an optical axis direction, and an optical apparatus using the lens barrel.

  In a lens barrel used for an optical apparatus such as a video camera or a digital camera, a thing using a linear actuator as a driving source of a moving lens group is known.

For example, Patent Document 1 discloses an example in which a coil is integrally provided in a lens barrel that holds a moving lens group, and a linear actuator is configured with a magnet provided on a fixed side.
JP 2002-214504 A

  However, in Patent Document 1, the shape of the actuator arranged in the lens barrel viewed from the optical axis direction is a rectangle, and there is a problem in downsizing the entire lens barrel, particularly in the case of a cylindrical shape. . An object of the present invention is to provide a smaller lens barrel and an optical device.

  In order to achieve the above object, in a lens barrel and an optical apparatus equipped with the lens barrel, the driving means is constituted by a coil and a magnet, and the coil or magnet is integrated with a holding member that holds the optical element. And the projection shape in the optical axis direction of the driving means for driving the holding member in the optical axis direction is formed in a fan shape, thereby further reducing the size of the lens barrel and the optical device mounted with the lens barrel. Configurable.

  As described above, according to the first invention of this application, the shape of the linear actuator that drives the second group lens group and the linear actuator that drives the fourth group lens group are fan-shaped, and the center of the fan shape is When it is approximately at the center, the cross-sectional shape is rounded, and the lens barrel and optical equipment using the lens barrel can be miniaturized.

  According to the second invention, the shape of the linear actuator that drives the second lens group and the linear actuator that drives the fourth lens group are fan-shaped, and the center of the fan shape does not coincide with the optical axis. However, when the fan-shaped center is on the optical axis side when viewed from the linear actuator that drives the second group lens group and the linear actuator that drives the fourth group lens group, the lens barrel and the optical device using the lens barrel are Miniaturization is possible.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 and FIG. 2 are explanatory diagrams when the present invention is applied to a lens barrel having a variable magnification optical system having a four-group configuration with convex and concave projections. FIG. 2 is a cross-sectional view of a main part of the present invention, and FIG. 1 is a cross-sectional view taken along line AA of FIG. For the sake of explanation, some shapes are omitted.

  Reference numeral 1 denotes a first lens group, 2 denotes a second lens group, which moves in the optical axis direction, 3 denotes a third lens group, and 4 denotes a fourth lens group, which moves in the optical axis direction. Reference numeral 6 denotes a second group lens barrel that holds the second lens group, and reference numeral 7 denotes a third lens barrel that holds the third lens.

  The second group lens barrel 6 serving as a holding member for holding the second lens group 2 has a sleeve portion 6a integrally and is supported by a well-known bar sleeve structure including a guide bar 12 and a guide bar 14, and light. The focal length is changed by moving in the axial direction. The guide bars 12 and 14 are fixed between the first group lens barrel 5 holding the first lens group 1 and the fixed barrel 13. Similarly, the fourth group lens barrel 8 which is a holding member that holds the fourth lens group 4 has a sleeve portion 8a integrally, and is supported by a known bar sleeve structure by the guide bar 14 and the guide bar 12. By moving in the direction of the optical axis, the focus is maintained during zooming and the focusing operation is performed.

  A low-pass filter 9 and a CCD 10 serving as an image sensor are fixed to the fixed barrel 13. Reference numerals 22 and 24 are sensor magnets magnetized in the direction of the optical axis, and are fixed to the fourth group lens barrel and the second group lens barrel, respectively. The MR sensor 21 and 23 are held in the lens barrel body, and the second group lens barrel 6 and the fourth group lens mirror are provided by providing sensor magnets 22 and 24 on the movable second group lens barrel 6 and the fourth group lens barrel 8. A position detecting means for the cylinder 8 is configured. The sensor magnets 22 and 24 extend long in the optical axis direction, and always face the MR sensors 21 and 23 at any position in the movable range of the second group lens barrel 6 and the fourth group lens barrel 8. The sensor magnets 22 and 24 are multipolarly magnetized in the optical axis direction. When the sensor magnets 22 and 24 move with respect to the MR sensors 21 and 23 together with the second group lens barrel 6 and the fourth group lens barrel 8. The absolute position in the optical axis direction of the variator lens group 2 and the focusing lens group 4 can be detected by continuously counting the electric signals output from the MR sensors 21 and 23 according to the magnetic change. As a result, the positions of the second lens group 2 and the fourth lens group 4 moving in the optical axis direction are detected. Reference numeral 25 denotes an aperture, and 26 denotes an aperture drive meter.

  The linear actuator, which is a driving means for driving the second group lens group 2, is composed of a coil 17, a magnet 16, and a yoke 18, and these components are each configured in a fan shape with the optical axis substantially at the center. . As shown in FIG. 2, they are arranged in a region represented by two two-dot chain lines R and R ′ and the outer periphery of the lens barrel, and the intersection point O of the two-dot chain lines R and R ′ is substantially the same as the optical axis. Match. Further, the inner shape does not necessarily need to be an R shape as long as it does not interfere with the photographing light flux. The linear actuator that drives the fourth group lens group 4 includes a coil 19, a magnet 15, and a yoke 20, and these components are configured in a fan shape with the optical axis as the center. As shown in FIG. 1, they are arranged in an area represented by two two-dot chain lines Q and Q ′ and the outer periphery of the lens barrel, and an intersection О of the two-dot chain lines Q and Q ′ is substantially the same as the optical axis. Match. Further, the inner shape does not necessarily need to be an R shape as long as it does not interfere with the photographing light flux. In this way, by constructing the actuator components in a fan shape about the center of the optical axis, the size of the lens barrel can be reduced as compared with the case where a conventionally known rectangular actuator is used. A coil 19 is integrally fixed to a fourth group lens barrel 8 holding the movable fourth lens group 4 by a method such as adhesion. On the other hand, the drive magnet 15 and the yoke 20 are fixed to the lens barrel body on the fixed side.

  These coils, magnets, and yokes constitute a linear motor, and a current that flows through the coil 19 generates a thrust force that drives the fourth lens barrel 8 in the optical axis direction. The second group lens barrel 6 is also driven with the same configuration.

  FIG. 3 is a block diagram of a camera body in an optical apparatus suitable for carrying out the present invention.

  Reference numeral 221 denotes a solid-state imaging device such as a CCD, and 222 denotes a drive source for the variator lens group 201b, which is a linear actuator composed of a coil 17, a yoke 18, and a magnet 16.

  Reference numeral 223 denotes a driving source for the focusing lens group 201d, which is a linear actuator including a coil, a yoke, and a magnet.

  Reference numeral 224 denotes a driving source for a diaphragm device 235 disposed between the variator lens group 201b and the afocal lens 201c.

  225 is a zoom encoder and 227 is a focus encoder. Each of these encoders detects the absolute position of the variator lens group 201b and the focusing lens group 201d in the optical axis direction.

  In order to detect the absolute position, it is common to use the method in which each lens group holding frame is abutted against the mechanical end when the power is turned on to find the initial position, and then the number of operation pulses input to the linear motor is continuously counted. Is. In this embodiment, the sensor magnet and the MR sensor magnetized in multiple poles are used, but an optical scale and a photo sensor may be used.

  Reference numeral 226 denotes a diaphragm encoder, which employs a system in which a Hall element is disposed inside a diaphragm drive source 224 such as a motor and detects the rotational positional relationship between the rotor and the stator.

  A CPU 232 controls the camera. Reference numeral 228 denotes a camera signal processing circuit which performs predetermined amplification, gamma correction, and the like on the output of the solid-state image sensor 221. The contrast signal of the video signal subjected to these predetermined processes passes through the AE gate 229 and the AF gate 230. That is, an optimum signal extraction range for exposure determination and focusing is set in this gate in the entire screen. The size of the gate may be variable or a plurality of gates may be provided.

  Reference numeral 231 denotes an AF signal processing circuit that processes an AF signal for AF (autofocus), and generates one or a plurality of outputs related to high-frequency components of the video signal. Reference numeral 233 denotes a zoom switch, and reference numeral 234 denotes a zoom tracking memory. The zoom tracking memory 234 stores information on the focusing lens position to be set according to the subject distance and the variator lens position at the time of zooming. Note that the memory in the CPU 232 may be used as the zoom tracking memory.

  For example, when the zoom switch 233 is operated by the photographer, the CPU 232 controls the zoom encoder 225 so that the predetermined positional relationship between the variator lens and the focusing lens calculated based on information in the zoom tracking memory 234 is maintained. The zoom driving source 222 and the focusing driving source 223 are driven and controlled so that the absolute position in the optical axis direction of the current variator lens as the detection result matches the calculated position where the variator lens should be set.

  In the autofocus operation, the CPU 232 controls the focusing drive source 223 so that the output of the AF signal processing circuit 231 has a peak.

(Second embodiment)
FIG. 4 shows a second embodiment of the present invention. 4 is a cross-sectional view of a lens barrel similar to FIG. As shown in FIG. 4, the linear actuator that drives the fourth lens group is arranged in an area represented by two two-dot chain lines P and P ′ and the outer periphery of the lens barrel. The intersection О ′ does not coincide with the optical axis, but is on the optical axis side when viewed from the linear actuator side that drives the fourth lens group 4. Further, the inner shape does not necessarily need to be an R shape as long as it does not interfere with the photographing light flux. Therefore, similarly to the first embodiment, the size of the lens barrel can be reduced as compared with the case where a conventionally known rectangular actuator is used.

  The above is the description of the embodiment of the present invention. However, the present invention is not limited to the configuration of the embodiment, and it is needless to say that any configuration may be used as long as the configuration is shown in the claims. Yes.

It is AA sectional drawing of FIG. It is sectional drawing which shows the structure of the zoom lens barrel which is 1st embodiment of this invention. It is a block block diagram of the optical apparatus of this invention. It is sectional drawing of the zoom lens barrel which shows 2nd embodiment of this invention.

Explanation of symbols

6 Second group lens barrel 8 Fourth group lens barrel 12, 14 Guide bar 15, 16, 27 Magnet 17, 19, 28 Coil 18, 20, 29 Yoke 21, 23 MR sensor 22, 24 Sensor magnet 25 Diaphragm 26 Diaphragm drive Meter

Claims (2)

  Drive means comprising a coil and a magnet, wherein the coil or magnet is integrally formed with a holding member that holds the optical element, and the lens barrel that drives the holding member in the direction of the optical axis includes the optical axis of the drive means. A lens barrel having a projection shape in a direction formed into a fan shape having an optical axis as a center, and an optical apparatus including the lens barrel.   Drive means comprising a coil and a magnet, wherein the coil or magnet is integrally formed with a holding member that holds the optical element, and the lens barrel that drives the holding member in the direction of the optical axis includes the optical axis of the drive means. A lens barrel characterized in that the projection shape in the direction is formed in a fan shape having a center in the optical axis direction, and an optical apparatus equipped with the lens barrel.

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