JP4858776B2 - LENS DEVICE AND IMAGING DEVICE - Google Patents

Description

The present invention relates to a lens apparatus and an imaging apparatus .

2. Description of the Related Art In recent years, there have been provided imaging apparatuses such as digital still cameras and digital video cameras that have a photographing optical system that performs zooming (magnification).
As a lens apparatus that constitutes such a photographing optical system, it has a fixed lens group whose position in the optical axis direction is fixed, and a movable lens group that can move in the optical axis direction. There is provided a device that performs a zooming operation by moving along an optical axis.
In the lens apparatus, when the movable lens group moves to the wide angle side and the telephoto side, the MTF (spatial frequency) as the entire photographing optical system, in other words, the resolution fluctuates. Therefore, it is necessary to finely adjust the position of the optical axis of the fixed lens group so as to be balanced. Such fine adjustment is important for improving the optical performance of the photographing optical system as the number of pixels of the image sensor increases.
Therefore, a lens device having an adjustment mechanism for finely adjusting the position of the fixed lens group in the direction orthogonal to the optical axis has been proposed (see Patent Document 1).
In this lens device, the adjustment mechanism is composed of two adjustment members and one adjustment biasing member, and the two adjustment members have their axes centered at an acute angle at the center of the fixed lens group. The adjustment biasing member that extends so as to intersect with each other and that is displaceable in a direction in which its tip abuts against two places on the outer peripheral surface of the fixed lens group and is in contact with or away from the optical axis. Is configured to urge the fixed lens group in a direction in contact with the two adjustment members.
JP 2005-55757 A

On the other hand, in recent years, there is a demand for further downsizing of the lens device, and therefore, the adjustment mechanism and other mechanisms (for example, a diaphragm mechanism and a focus mechanism) adjacent to the adjustment mechanism are arranged closer to each other. There is a need.
However, in the above-described conventional device, the two adjustment members extend so that their axial centers intersect at an acute angle at the center of the fixed lens group. There is a limit to disposing them close to each other, which is disadvantageous in reducing the size especially in the optical axis direction.
The present invention has been made in view of such circumstances, and it is an object of the present invention to provide an imaging device and a lens device that are advantageous in reducing the size.

To achieve the above object, the present invention provides a lens frame that supports a lens, a wall portion having an opening, and the lens frame is moved in the optical axis direction of the lens with the lens facing the opening. A lens device comprising: a support mechanism for supporting the lens frame; and an adjustment mechanism for displacing the lens frame in a plane orthogonal to the optical axis. The adjustment mechanism includes two adjustment members and one adjustment member. The two adjustment members extend so that their extension lines intersect at a position away from the center of the lens, and the two adjustment members are the lens frame. The adjustment urging member is provided so as to be displaceable in the axial direction by contacting two different positions of the lens frame, and the adjustment biasing member is configured so that the two different positions of the lens frame are in contact with the two adjustment members. It urges the frame, urging for the adjustment The material is composed of a torsion spring provided between the wall portion and the lens frame, and the extension line of the axial center of the two adjusting members extends so as to intersect at a location outside the lens in the radial direction. In addition, the lens and the torsion spring are located inside a region surrounded by the extension lines when viewed from the optical axis direction .
The present invention also provides a lens frame that supports the lens, a wall portion having an opening, and a support mechanism that supports the lens frame so as not to move in the optical axis direction of the lens with the lens facing the opening. An image pickup apparatus including an adjustment mechanism for displacing the lens frame in a plane orthogonal to the optical axis, and an image pickup device disposed behind the lens, wherein the adjustment mechanism includes two adjustment members; And the two adjustment members extend so that their extension lines intersect at a position away from the center of the lens, and the two adjustment members The member is provided so as to be in contact with two different positions of the lens frame and displaceable in the axial direction thereof, and the adjustment biasing member has two different positions of the lens frame that contact the two adjustment members. said lens frame and biased in a direction in contact The adjustment biasing member is constituted by a torsion spring provided between the wall portion and the lens frame, and the extension line of the axis of the two adjustment members intersects at a location outside the lens in the radial direction. And the lens and the torsion spring are located inside a region surrounded by the extension lines when viewed from the optical axis direction .

  Therefore, according to the present invention, it is possible to secure a large space between the two adjustment members around the lens frame, and other mechanisms adjacent to the adjustment mechanism in these spaces, such as a diaphragm mechanism and a focus mechanism. Therefore, it is advantageous in reducing the size of the imaging device in the optical axis direction.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of an imaging apparatus according to the present embodiment, and FIG. 2 is a block diagram illustrating a configuration of the imaging apparatus according to the present embodiment.
As shown in FIG. 1, the imaging apparatus 10 of the present embodiment is a digital still camera, and has a case 12 that constitutes an exterior.
A lens barrel 16 that houses and holds the photographing optical system 14 is provided at a position near the front right side of the case 12, a flash unit 18 that emits flash light at a position near the upper front of the case 12, and an objective lens of the optical viewfinder. 20 etc. are provided. In this specification, the front refers to the subject side, and the rear refers to the imaging side.
A shutter button 22 is provided on the upper end surface of the case 12, and a plurality of operations for performing various operations such as an eyepiece window 24 of the optical finder, power on / off, photographing mode, and reproduction mode are provided on the rear surface of the case 12. And an operation switch 26, a display 28 (FIG. 2) for displaying captured images, and the like.

  As shown in FIG. 2, the imaging device 10 includes an imaging device 30 </ b> A configured by a CCD or CMOS sensor that captures a subject image formed by the imaging optical system 14, and an imaging signal output from the imaging device 30 </ b> A. An image processing unit 30C that generates image data based on the image data and records the image data in a storage medium 30B such as a memory card, a display processing unit 30D that displays the image data on the display 28, and second and fourth lens groups 14B and 14D (described later). 3), a control unit 30F including a CPU for controlling the image processing unit 30C, the display processing unit 30D, and the driving unit 30E according to the operation of the operation switch 26 and the shutter button 22. It has.

Next, a schematic configuration of the lens barrel 16 will be described.
FIG. 3 is a cross-sectional view of the lens barrel 16.
As shown in FIG. 3, the lens barrel 16 is optically configured as a four-group inner focus.
The lens barrel 16 has a first tube portion 32 and a second tube portion 34 therein.
The first cylinder part 32 is formed to have a rectangular cross section, and the first cylinder part 32 includes a rear wall 3202 and a peripheral wall 3204 erected forward from the periphery of the rear wall 3202.
The second cylindrical portion 34 is attached to the front end of the first cylindrical portion 32, and the first lens group 14A is accommodated in the second cylindrical portion 34.
A second lens group 14B, a third lens group 14C, and a fourth lens group 14D are arranged in this order from the front side to the rear side behind the first lens group 14A inside the first cylindrical portion 32.
The rear wall 3202 is provided with an opening 3206, and the imaging element 30 </ b> A is attached so as to face the opening 3206.

The first lens group 14A and the third lens group 14C are configured as fixed lens groups fixed to the first cylinder part 32 and the second cylinder part 34, and the second lens group 14B and the fourth lens group 14D are arranged in the optical axis direction. The movable lens group is configured to be movable.
A wall 3208 is formed in the middle of the first cylindrical portion 32 in the optical axis direction, and an opening 3210 centering on the optical axis is provided at the center of the wall 3208.
A rear lens 36 is attached to a position near the rear of the opening 3210 in a state where the center of the rear lens 36 is aligned with the optical axis.
A front lens 38 (corresponding to a lens in claims) is disposed in front of the opening 3210, that is, in front of the rear lens 36, and the front lens 38 and the rear lens 36 constitute a third lens group 14C. ing.
Then, the second and fourth lens groups 14B and 14D are moved in the optical axis direction of the first to fourth lens groups 14A, 14B, 14C and 14D along a predetermined cam curve by the driving force of the driving unit 30E. It is configured to zoom between wide angle and telephoto.
In front of the front lens 38, a diaphragm mechanism 40 for adjusting the amount of light flux guided to the image sensor 30A by the first to fourth lens groups 14A, 14B, 14C, 14D is disposed.
As such an aperture mechanism 40, for example, a pair of aperture blades are provided so as to sandwich the optical axis of the photographing optical system 14, and the aperture blades are moved away from each other in a direction perpendicular to the optical axis. Thus, it is possible to use a variety of conventionally known configurations such as those that change the diameter of the opening formed between the edges of the pair of diaphragm blades.
Such a diaphragm mechanism 40 is configured to include an actuator and a transmission mechanism for transmitting the force from the actuator to the diaphragm blades.

Next, the configuration of the lens device will be described in detail.
4 is an exploded perspective view showing the mounting structure of the front lens 38 according to the present embodiment, FIG. 5 is a front view of FIG. 4 viewed from the front, and FIG. 6 is a front view of FIG. 5 with the leaf spring 48 removed. .
The lens device includes a lens frame 42, a wall portion 3208, a support mechanism 44, and an adjustment mechanism 46.
As shown in FIGS. 5 and 6, the lens frame 42, the support mechanism 44, and the adjustment mechanism 46 are accommodated inside the lens barrel 16, and the wall portion 3208 is formed integrally with the lens barrel 16.

As shown in FIG. 4, the lens frame 42 supports the outer peripheral portion of the front lens 38.
As shown in FIG. 3, the opening 3210 of the wall 3208 is formed in a size corresponding to the front lens 38.

As shown in FIG. 3, the support mechanism 44 supports the lens frame 42 so as not to move in the optical axis direction of the front lens 38 with the front lens 38 facing the opening 3210.
The support mechanism 44 includes a frame-shaped leaf spring 48 that elastically contacts the lens frame 42 and abuts the lens frame 42 against the wall portion 3208.

As shown in FIGS. 4 and 5, the leaf spring 48 is provided with an annular piece 4801, an opening 4802 and a spring piece 4804.
An opening 4802 is provided at the center of the annular piece 4801, and the opening 4802 is formed in a size corresponding to the front lens 38.
The spring piece 4804 is formed on the annular piece 4801 and is configured to urge the rear surface of the lens frame 42 in a direction to contact the wall portion 3208 as shown in FIG. 3 by contacting the front surface of the lens frame 42. ing.
In this example, three spring pieces 4804 are provided at intervals of 120 degrees in the circumferential direction of the annular piece 4801, and each extend in an arc shape along the outer peripheral edge of the opening 4802 at the inner peripheral portion of the annular piece 4801. Each spring piece 4804 is formed so as to be separated from the opening 4802 along the optical axis direction and displaced toward the front lens 38 toward the tip.
As shown in FIG. 4, an engaging claw 4810 protruding outward in the radial direction of the opening 4802 is formed in the center of the lower portion of the annular piece 4801, and is in contact with two places sandwiching the engaging claw 4810. Each piece 4812 is formed.
Two spring pieces 4814 are formed on the upper part of the annular piece 4801.
In addition, positioning holes 4816 are formed in the base portion of the engaging claw 4810 and the base portion of one spring piece 4814, respectively.

As shown in FIG. 3, an engagement hole 3210 that engages with an engagement claw 4810 of the leaf spring 48 is formed in the lower portion of the peripheral wall 3204 of the first cylindrical portion 32, and 2 of the leaf spring 48 is formed in the upper portion. Two engaging holes 3212 with which the two spring pieces 4814 are engaged are formed. As shown in FIG. 5, two positioning bosses 3214 inserted into the two positioning holes 4816 are formed in the wall portion 3208. .
Therefore, as shown in FIG. 3, the leaf spring 48 has the engagement claw 4810 engaged with the engagement hole 3210 and the two spring pieces 4814 engaged with the two engagement holes 3212. The contact piece 4812 is in contact with the lower portion of the wall 3208 due to the elasticity of the spring piece 4814, and the two positioning bosses 3214 are inserted into the two positioning holes 4816, thereby being positioned with respect to the wall 3208. Will be held at.

The adjustment mechanism 46 is for displacing the lens frame 42 in a plane orthogonal to the optical axis.
As shown in FIG. 4, the adjustment mechanism 46 includes two adjustment members 50 and one adjustment biasing member 52.
As shown in FIG. 6, the two adjustment members 50 extend so that the extension lines 50 </ b> A of their axial centers intersect at a position away from the center of the front lens 38, and the two adjustment members 50 are in the lens frame. It is provided so that it can contact | abut at two different places of 42, and can displace in those axial center directions.
In the present embodiment, the extension line 50A of the axial center of the two adjusting members 50 extends so as to intersect at a right angle at a location outside the front lens 38 in the radial direction, and is viewed from the optical axis direction. The front lens 38 is located inside the area surrounded by the extension lines 50A.
Further, in the present embodiment, two different positions of the lens frame 42 with which the two adjustment members 50 abut are on an imaginary line L1 that extends in a plane that passes through the optical axis of the front lens 38 and is orthogonal to the optical axis. Or in the vicinity of the imaginary line L1.
In the present embodiment, two different positions of the lens frame 42 with which the two adjustment members 50 abut are located in the vicinity of the outer peripheral portion of the front lens 38.
In other words, the two adjustment members 50 are provided around the lens frame 42 so as to ensure a large space between the adjustment members 50.
In the present embodiment, the two adjustment members 50 each have a male screw portion 5002, and the two adjustment members 50 are arranged by screwing the male screw portion 5002 into the female screw 3208 </ b> A of the wall portion 3208.
Each female screw 3208A is formed on a boss portion provided on each inner surface of the upper wall 3204A and the side wall 3204B of the peripheral wall 3204 having a rectangular cross section. Located in the upper and side walls 3204B, in this embodiment, the two adjusting members 50 extend in directions orthogonal to the upper wall 3204A and the side wall 3204B, respectively.

The adjustment biasing member 52 biases the lens frame 42 in a direction in which two different positions of the lens frame 42 come into contact with the two adjustment members 50.
The adjustment biasing member 52 includes a torsion spring 5202 provided across the wall 3208 and the lens frame 42.
Similar to the front lens 38, the torsion spring 5202 is located inside a region surrounded by the extension line 50 </ b> A of the axis of the two adjustment members 50 when viewed from the optical axis direction.
By using the torsion spring 5202 as the adjustment urging member 52, the adjustment urging member 52 is downsized.

Next, the position adjustment of the front lens 38 will be described.
In the front lens 38, the spring piece 2406 urges the front surface of the lens frame 42 so that the rear surface of the lens frame 42 is in contact with the wall portion 3208. In this state, the front lens 38 is in a direction perpendicular to the optical axis. It can be moved.
Here, when only one of the two adjustment members 50 is rotated and moved in the axial direction of the adjustment member 50, the leading ends of the two adjustment members 50 are urged by the urging force of the adjustment urging member 52. The lens frame 42 affixed to the oscillates along the plane perpendicular to the optical axis following the movement of the one adjustment member 50, with the point of contact with the tip of the other adjustment member 50 not rotated as a fulcrum. Therefore, the front lens 38 is displaced along the plane perpendicular to the optical axis integrally with the lens frame 42.
On the contrary, when only the other adjustment member 50 of the two adjustment members 50 is rotated and moved in the axial direction of the adjustment member 50, the two biasing forces of the adjustment biasing member 52 cause the two The lens frame 42 applied to the tip of the adjustment member 50 is a surface orthogonal to the optical axis following the movement of the other adjustment member 50, with the point of contact with the tip of the one adjustment member 50 not rotated as a fulcrum. Therefore, the front lens 38 is displaced along a plane perpendicular to the optical axis integrally with the lens frame 42.
Thus, by rotating the two adjusting members 50, the position of the front lens 38 can be displaced in a direction perpendicular to the optical axis.
The position adjustment in the direction orthogonal to the optical axis of the front lens 38 is performed by moving the second and fourth lens groups 12 and 16 to the wide-angle side and the telephoto side, respectively. 14C and 14D as a whole, while measuring the MTF (spatial frequency), in other words, the resolution variation, the variation is balanced between the wide angle side and the telephoto side.

Next, the fact that the position of the front lens 38 can be displaced in the direction orthogonal to the optical axis by rotating the two adjusting members 50 will be further described with reference to the experimental results of FIG.
FIG. 7 is a diagram showing the relationship between the displacement amounts (shift amounts) of the two adjustment members 50 and the displacement amount of the optical axis of the front lens 38. In FIG.
That is, in FIG. 6, an X axis and a Y axis that intersect with the optical axis and are orthogonal to each other are set in a plane orthogonal to the optical axis. In the present embodiment, the X axis is parallel to the axial direction of one adjustment member 50, and the Y axis is parallel to the axial direction of the other adjustment member 50.
In FIG. 7, the portion indicated by the symbol A is in a state where the Y-axis side adjustment member 50 is positioned at the reference position in the direction away from the lens frame 42 (the rotation angle of the Y-axis side adjustment member 50 is 0 degree). The X-axis side adjustment member 50 is fixed and positioned close to the lens frame 42 from the state where the X-axis side adjustment member 50 is positioned at the reference position in the direction farthest from the lens frame 42 (the rotation angle of the X-axis side adjustment member 50 is 0 degree). The displacement of the optical axis of the front lens 38 is shown by the coordinates of the X and Y axes when it is displaced to the maximum position in the direction of rotation (the rotation angle of the adjustment member 50 on the X axis side is 360 degrees). It is data.

  Hereinafter, in the same manner as described above, the portion indicated by reference numeral B in FIG. 7 is a state where the X-axis side adjustment member 50 is positioned at the maximum position in the direction of approaching the lens frame 42 (the X-axis side adjustment member 50). The rotation angle of the Y-axis side adjustment member 50 is fixed at a reference position in the direction farthest from the lens frame 42 (the rotation angle of the Y-axis side adjustment member 50 is 0). Degree), the displacement of the optical axis of the front lens 38 when it is displaced to the maximum position in the direction close to the lens frame 42 (the rotation angle of the adjustment member 50 on the Y-axis side is 360 degrees) is the X-axis. , Data indicated by Y-axis coordinates.

  In FIG. 7, the portion indicated by reference character C is in a state where the X-axis side adjustment member 50 is positioned at the reference position in the direction away from the lens frame 42 (the rotation angle of the X-axis side adjustment member 50 is 0 degree). The Y-axis side adjustment member 50 is fixed and moved closer to the lens frame 42 when the Y-axis side adjustment member 50 is positioned at the reference position in the direction farthest from the lens frame 42 (the rotation angle of the Y-axis side adjustment member 50 is 0 degree). The displacement of the optical axis of the front lens 38 when it is displaced to the maximum position in the direction of rotation (the rotation angle of the adjustment member 50 on the Y-axis side is 360 degrees) is indicated by the X-axis and Y-axis coordinates. It is data.

7 is a state where the Y-axis side adjustment member 50 is positioned at the maximum position in the direction close to the lens frame 42 (the rotation angle of the Y-axis side adjustment member 50 is 360 degrees). The X-axis side adjustment member 50 is fixed and positioned close to the lens frame 42 from the state where the X-axis side adjustment member 50 is positioned at the reference position in the direction farthest from the lens frame 42 (the rotation angle of the X-axis side adjustment member 50 is 0 degree). The displacement of the optical axis of the front lens 38 is shown by the coordinates of the X and Y axes when it is displaced to the maximum position in the direction of rotation (the rotation angle of the adjustment member 50 on the X axis side is 360 degrees). It is data.
That is, by rotating the two adjusting members 50, the position of the front lens 38 can be arbitrarily set within a plane orthogonal to the optical axis within the range of the rhombus surrounded by the lines indicated by reference signs A, B, C, and D. Can be displaced.
In other words, the adjustment range of the optical axis of the front lens 38 by the adjustment mechanism 46 is a diamond-shaped range surrounded by lines indicated by reference signs A, B, C, and D. In other words, the photographic optical system 14 including the front lens 38 may be designed so that the adjustment range is within this rhombus range.

Therefore, according to the present embodiment, the position of the front lens 38 can be adjusted.
In the present embodiment, the two adjustment members 50 extend so that the extension lines 50A of their axial centers intersect at a position away from the center of the front lens 38, so that the two adjustment members 50 are arranged around the lens frame 42. A large space can be secured between the adjusting members 50, and other mechanisms adjacent to the adjusting mechanism 46, such as the diaphragm mechanism 40 and the focus mechanism, can be disposed in these spaces. This is advantageous in reducing the size of the imaging device 10 in the optical axis direction.
Further, the two adjustment members 50 extend so that the extension lines 50 </ b> A of their axial centers intersect at a place away from the center of the front lens 38, so that the lens frame 42 with respect to the displacement of each adjustment member 50. Therefore, it is possible to precisely adjust the position of the front lens 38, which is advantageous in improving the optical performance of the imaging optical system 14 as the number of pixels of the image sensor 30A increases.

It is a perspective view of the imaging device of this Embodiment. It is a block diagram which shows the structure of the imaging device of this Embodiment. FIG. 3 is a cross-sectional view of the lens barrel 16. It is a disassembled perspective view which shows the attachment structure of the front lens 38 which concerns on this Embodiment. It is the front view which looked at FIG. 4 from the front. It is the front view which removed the leaf | plate spring 48 from FIG. FIG. 6 is a diagram showing the relationship between the amount of displacement (shift amount) of two adjusting members 50 and the amount of displacement of the optical axis of the front lens 38.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Imaging device, 30A ... Imaging element, 3208 ... Wall part, 3210 ... Opening part, 38 ... Front lens, 42 ... Lens frame, 44 ... Support mechanism, 46 ... Adjustment mechanism, 50 ... ... adjusting member, 52 ... adjusting biasing member.

Claims (8)

A lens frame that supports the lens;
A wall having an opening;
A support mechanism for supporting the lens frame so as not to move in the optical axis direction of the lens with the lens facing the opening;
An adjustment mechanism that displaces the lens frame in a plane orthogonal to the optical axis,
The adjustment mechanism includes two adjustment members and one adjustment biasing member,
The two adjustment members extend so that their extension lines intersect at a position away from the center of the lens, and the two adjustment members abut against two different positions of the lens frame. Provided to be displaceable in the axial direction thereof,
The adjustment biasing member biases the lens frame in a direction in which two different positions of the lens frame are in contact with the two adjustment members,
The adjustment biasing member includes a torsion spring provided across the wall portion and the lens frame,
The extension line of the axial center of the two adjusting members extends so as to intersect at a location outside the lens in the radial direction, and is inside the region surrounded by the extension line when viewed from the optical axis direction. The lens and the torsion spring are located in
A lens device. The extension line of the axis of the two adjusting members extends so as to intersect at a right angle at a location outside the lens in the radial direction.
The lens apparatus according to claim 1. Two different positions where the two adjusting members abut on the lens frame are located on an imaginary line extending through a plane orthogonal to the optical axis through the optical axis of the lens, or in the vicinity of the imaginary line Located in the
The lens apparatus according to claim 1. Two different positions where the two adjusting members abut against the lens frame are located in the vicinity of the outer periphery of the lens.
The lens apparatus according to claim 1. Each of the two adjustment members has a male thread portion,
Each of the two adjusting members is disposed by screwing the male screw portion with the female screw of the wall portion,
The lens apparatus according to claim 1. The support mechanism includes a frame-shaped leaf spring that elastically contacts the lens frame and causes the lens frame to abut against the wall portion.
The lens apparatus according to claim 1. The support mechanism includes a frame-shaped leaf spring that elastically contacts the lens frame and causes the lens frame to contact the wall portion;
The imaging apparatus includes a lens barrel that houses the lens frame, the support mechanism, and the adjustment mechanism.
The wall is provided integrally with the lens barrel,
The lens apparatus according to claim 1. A lens frame that supports the lens;
A wall having an opening;
A support mechanism for supporting the lens frame so as not to move in the optical axis direction of the lens with the lens facing the opening;
An adjustment mechanism for displacing the lens frame in a plane orthogonal to the optical axis;
An imaging device including an imaging element disposed behind the lens,
The adjustment mechanism includes two adjustment members and one adjustment biasing member,
The two adjustment members extend so that their extension lines intersect at a position away from the center of the lens, and the two adjustment members abut against two different positions of the lens frame. Provided to be displaceable in the axial direction thereof,
The adjustment biasing member biases the lens frame in a direction in which two different positions of the lens frame are in contact with the two adjustment members,
The adjustment biasing member includes a torsion spring provided across the wall portion and the lens frame,
The extension line of the axial center of the two adjusting members extends so as to intersect at a location outside the lens in the radial direction, and is inside the region surrounded by the extension line when viewed from the optical axis direction. The lens and the torsion spring are located in
An imaging apparatus characterized by that.

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