JP2012053492A - Light quantity adjusting device, optical device, and imaging apparatus equipped with these devices - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve reduction in thickness and a diameter in the thickness direction of the optical axis direction.SOLUTION: A light quantity adjusting device has at least one blade member 205 and 206 and driving means 210 for changing the passing luminous flux quantity by opening and closing the blade member in a direction orthogonal to an optical axis, where the blade member is arranged between first and second optical members 101 and 201. At least part of the blade member has a curved surface shape, which is approximately the same shape as the curved surface shape of at least one of the first optical member and the second optical member on the blade member side.

Description

  The present invention relates to a light amount adjusting device such as a diaphragm device, a lens barrel having the light amount adjusting device, and an imaging device including these devices.

  In recent years, downsizing of photographing apparatuses such as cameras has been promoted. In particular, in order to reduce the thickness of the lens barrel that is configured so that the lens part is extended from the camera body during shooting and the lens interval is set to a predetermined position, the camera body is set as close as possible to the camera body except during shooting. I am trying to store it. In addition, the diaphragm and shutter device arranged in the optical system are housed so as to make the distance between the front and rear lenses as short as possible. In order to further reduce the thickness of the camera, it is conceivable to reduce the number of lenses. However, it is difficult to suppress the aberration of the optical system, which deteriorates the optical performance.

  Therefore, in Japanese Patent Application Laid-Open No. 2001-281513 (Patent Document 1), focusing on the deformation direction when the diaphragm blades are closed, the lens curved surface bites into the space vacated by the deformation, and the thickness of the lens barrel when retracted A technique for reducing the thickness has been proposed. Japanese Patent No. 3496667 (Patent Document 2) proposes a technique for reducing the thickness of the lens barrel when the lens barrel is retracted by fully opening the aperture blades and the shutter blades when not photographing and storing the lens in the opening. Has been. Japanese Patent Laid-Open No. 2003-315861 (Patent Document 3) proposes a technique for reducing the thickness of the lens barrel when retracted by retracting a part of the lens out of the photographing optical path when the lens is housed.

JP 2001-281513 A Japanese Patent No. 3496667 JP 2003-315861 A

  However, in the apparatus proposed in Patent Document 1 described above, the diaphragm blades are not actively deformed, and if the amount of deformation is increased, the function of the original diaphragm blades may be affected. There has been a problem that the effect of significantly reducing the collapsed thickness is small.

  Further, in the apparatus proposed in Patent Document 2 described above, it is necessary to retract the blade beyond the optical path more than necessary in order to completely retract the lens into the aperture when not photographing. Therefore, a blade retracting space is required, and the outer diameter of the lens barrel is increased. Further, since there are no blades that shield the optical path during non-photographing, it is necessary to provide another shielding member such as a barrier to block the optical path and prevent the film from being exposed to light and the sensor such as a CCD from failing. There was a problem.

  Further, in the apparatus proposed in Patent Document 3, although the retractable length can be shortened, it is inevitable that the lens barrel diameter increases, and there is a possibility that the performance may be affected by looseness of the retraction structure parts. There was a problem.

(Object of invention)
An object of the present invention is to provide a light amount adjusting device, a lens barrel, and an imaging device that can achieve a reduction in thickness and a reduction in diameter in the thickness direction in the optical axis direction.

  In order to achieve the above object, the present invention comprises at least one blade member and drive means for changing the amount of passing light flux by opening and closing the blade member in a direction orthogonal to the optical axis, In the light amount adjusting device disposed between the first and second optical members, the first optical member and the second optical member are inserted into a part of the first optical member. The light quantity adjusting device is such that the blade member is disposed between the second optical members.

  According to the present invention, it is possible to provide a light amount adjusting device, a lens barrel, or an imaging device capable of achieving a reduction in thickness and a reduction in diameter in the thickness direction in the optical axis direction.

It is sectional drawing which shows the time of retraction of the lens-barrel incorporating the diaphragm | throttle device concerning one Example of this invention. It is sectional drawing which shows the time of imaging | photography of the lens barrel incorporating the aperture device concerning one Example of this invention. It is a disassembled perspective view of the aperture_diaphragm | restriction apparatus concerning one Example of this invention. It is a perspective view which shows the time of minimum diaphragming of the diaphragm | throttle device concerning one Example of this invention. It is a perspective view which shows the time of intermediate | middle aperture of the aperture_diaphragm | restriction apparatus concerning one Example of this invention. It is a perspective view which shows the time of full opening of the aperture_diaphragm | restriction apparatus concerning one Example of this invention. It is a top view which shows the time of the minimum aperture_diaphragm | restriction of the aperture_diaphragm | restriction apparatus concerning one Example of this invention. It is a top view which shows the time of intermediate | middle aperture of the aperture_diaphragm | restriction apparatus concerning one Example of this invention. It is a top view which shows the time of full opening of the aperture_diaphragm | restriction apparatus concerning one Example of this invention. It is sectional drawing at the time of retracting of the lens barrel in a prior art example.

  The best mode for carrying out the present invention is as shown in the following examples.

  FIG. 1 is a cross-sectional view of a lens barrel used in a digital still camera incorporating a diaphragm device according to an embodiment of the present invention when the lens barrel is retracted.

  The first group lens 101 is fixed to the first group lens frame 102, and cam pins (not shown) project in three directions on the outer periphery of the first group lens frame 102 and are engaged with cam grooves formed in the cam cylinder 502. ing. On the image plane side of the first lens group 101, a plurality of diaphragm blades 203 to 206 (203 and 204 are not shown in FIG. 1, refer to FIG. 3) and the diaphragm blades 203 to 206 are moved in the optical axis direction. A cover plate 211 to be regulated is attached using the second group lens frame 207 as a substrate. Further, a diaphragm ring 208 that drives the diaphragm blades 203, 204, 205, and 206, a motor 210 that rotationally drives the diaphragm ring 208, and a motor gear 209 are attached using the second group lens frame 207 as a substrate. And these comprise the diaphragm | throttle device. Details will be described with reference to FIG.

  A second group lens A 201 and a second group lens B 202 are fixed to the second group lens frame 207 in order from the subject side on the imaging surface side of the diaphragm blades 203 to 206. A cam pin (not shown) projects in three directions on the outer periphery of the second group lens frame 207 and is engaged with a cam groove formed in the cam cylinder 502. Between the first group lens frame 102 and the second group lens frame 207 and the cam cylinder 502, there is a rectilinear cylinder 503 provided with rectilinear grooves for linearly guiding in the optical axis direction in which the respective cam pins are fitted. Then, the rectilinear cylinder 503 rotates the cam cylinder 502 around the optical axis by a drive source (not shown), whereby the first group lens frame 102 and the second group lens frame 207 are guided to the cam groove and the rectilinear groove, and a predetermined position is obtained. The feeding operation is performed while moving straight in the optical axis direction.

  The second group lens frame 207 is provided with a third group lens frame 302 including a third group lens 301 so as to be movable. The second group lens frame 207 moves in the optical axis direction together with the second group lens (second group lens A 201 and second group lens B 202). Is possible. On the second group lens frame 207, a motor (not shown) for driving the third group lens frame 302 and a guide bar for guiding movement in the optical axis direction are provided, and the distance from the second group lens can be changed. It can be done. It is also possible to adjust the focal position using a motor that drives the third group lens frame 302.

  FIG. 2 is a cross-sectional view of the lens barrel showing a state in which the distance between the lenses is set in a photographing enabled state. At this time, since the distance between the first group lens 101 and the second group lens A 201 is widened, the diaphragm blades 203 to 206 can be fully opened, and the photographing light beam can be incident on the CCD 402.

  In the above configuration, after the diaphragm blades 203 to 206 are driven to a predetermined position by a shooting start signal and controlled to have an appropriate exposure amount, charges are accumulated in the CCD 402 and shooting is performed. The charge accumulation time is assumed to be controlled by an electronic shutter function provided in the CCD 402, but the diaphragm blades of this embodiment may be configured to be fully closed and may be used as a mechanical shutter. Further, a shutter composed of mechanical parts may be separately provided in the lens barrel.

  Next, the operation and shape of the diaphragm blades 203 to 206 will be described. In the present embodiment, the imaging surface side of the first group lens 101 disposed on the subject side of the diaphragm blades 203 to 206 has a concave shape, and the second group lens disposed on the imaging surface side of the diaphragm blades 203 to 206. The object side of A201 is a convex surface. Since the space generated when the first group lens 101 and the second group lens A 201 are brought close to each other is a curved space, a part of the diaphragm blades 203 to 206 is formed in a curved shape so as to extend over the curved space. . The material of the diaphragm blades 203 to 206 is not particularly limited. For example, since a thin-wall molding technique using a resin has been established in recent years, it may be molded integrally with a resin including a curved surface portion, or a curved surface portion may be formed by drawing a metal thin plate.

  As shown in FIG. 2, the distance between the first lens group 101 and the second lens group A 201 is widened so that the diaphragm blades 203 to 206 move linearly within a plane perpendicular to the optical axis. There is no interference with the frame or lens.

  The diaphragm unit and the second group lens frame 207 are separated, and the second group lens frame 207 is also moved away from the diaphragm device so that the diaphragm device and the second group lens do not overlap in the optical axis direction during photographing. You can also. In this case, the operable range of the diaphragm blades 203 to 206 is widened, and is not limited to a linear motion in a plane perpendicular to the optical axis, but can also be rotated.

  When the retracting operation of the lens barrel is started by a power OFF signal or the like, if the retracting operation is performed with the aperture blades 203 to 206 fully opened as shown in FIG. 2, the aperture blades 203 to 206 and the first group lens frame 102 interfere with each other. Can not shorten the retractable length. For this reason, the first group lens 101 and the second group lens A 201 are brought close to each other after the diaphragm blades 203 to 206 are set to the minimum diaphragm state or the fully closed state. Accordingly, the convex surface of the second group lens can enter the concave surface of the first group lens 101 while keeping the curved surface space where the diaphragm blades 203 to 206 can be disposed at a minimum, so that the collapsed thickness can be minimized.

  FIG. 10 is a conventional example of a lens barrel that shows a retracted state similar to that of FIG. 1 by replacing the diaphragm apparatus according to the present embodiment with a conventional diaphragm apparatus.

  All of the diaphragm blades 703 to 706 have a planar shape, and are moved in a plane perpendicular to the optical axis by rotational driving of the diaphragm ring 708 to control the amount of photographing light. The distance between the first group lens 101 on the subject side of the diaphragm blades 703 to 706 and the second group lens A 201 on the imaging surface side is at least between the fixing portion 102a of the first group lens 101, the cover plate 711, and the diaphragm blades 703 to 706. The total amount of the working space and the thickness of the aperture ring 708 in the optical axis direction is required. It is inevitable that the lens barrel becomes thicker than the retracted length of the lens barrel according to this embodiment shown in FIG.

  Next, the diaphragm device in the present embodiment will be described.

  FIG. 3 is an exploded perspective view of the diaphragm device. The aperture device includes a cover plate 211, aperture blades 203 to 206, an aperture ring 208, a second group lens frame 207, a drive motor 210, and a motor gear 209 from the subject side. A motor gear 209 for transmitting the driving force of the drive motor 210 is gear-coupled to a gear portion 208e formed on the outer peripheral portion of the aperture ring 208. Then, when the drive motor 210 is energized, the aperture ring 208 rotates about the optical axis.

  The aperture ring 208 includes arc-shaped cam grooves 208a, 208b, 208c, and 208d, and shaft portions 203a, 204a, and 205a (not shown) provided on the aperture blades 203 to 206, respectively, in the cam grooves 208a to 208d. ), 206a (not shown) are fitted. Each of the diaphragm blades 203 to 206 is also provided with two shaft portions 203b, 204b, 205b, and 206b on the subject side. And it fits into the linear groove part 211a, 211b, 211c, 211d provided in the cover board 211, respectively.

  When the diaphragm ring 208 rotates around the optical axis by energizing the drive motor 210, the diaphragm blades 203 to 206 are guided by linear grooves 211a to 211d provided in the cover plate 211, and are perpendicular to the optical axis. Move straight on the plane.

  4 to 6 are perspective views showing the operation states of the diaphragm blades 203 to 206, and FIGS. 7 to 9 are plan views showing the operation states of the diaphragm blades 203 to 206. FIG.

  The diaphragm blades 203 and 204 are arranged in the same plane perpendicular to the optical axis, but have shapes that do not overlap each other. Further, the cam grooves 208a and 208b formed on the aperture ring 208 have substantially the same shape symmetrical with respect to the optical axis so that the movement amounts are substantially the same. By rotating the diaphragm ring 208 to the right, the diaphragm blade 203 moves in the right direction and the diaphragm blade 204 moves in the left direction as viewed from the subject side, in the direction of opening the diaphragm opening by the same amount of movement.

  The diaphragm blades 205 and 206 are disposed in the same plane perpendicular to the optical axis on the imaging surface side from the diaphragm blades 203 and 204, but are disposed in a shape that does not overlap each other. Further, the cam grooves 208c and 208d formed on the aperture ring 208 have substantially the same shape symmetrical with respect to the optical axis so that the movement amounts of the aperture blades 205 and 206 are substantially the same. By rotating the diaphragm ring 208 to the right, the diaphragm blade 205 moves upward and the diaphragm blade 206 moves downward in the direction of opening the diaphragm opening by the same amount of movement as viewed from the subject side. At this time, if the cam grooves 208a (208b) and 208c (208d) of the diaphragm ring 208 have the same shape, the movement amounts of the four diaphragm blades 203 to 206 are substantially the same, and are formed on the respective diaphragm blades 203 to 206. Curved surface portions interfere with each other.

  Therefore, the shapes of the cam grooves 208a (208b) and 208c (208d) of the aperture ring 208 are made different so that the amount of movement by the cam grooves 208a (208b) is larger than the amount of movement of the cam grooves 208c (208d). Yes. At the same time, the diaphragm blades 203 and 204 that cover the diaphragm blades 205 and 206 and operate in the left-right direction are operated prior to the diaphragm blades 205 and 206 so that the curved surface portions of the diaphragm blades 203 to 206 are connected to each other. To prevent interference.

  Accordingly, the four diaphragm blades 203 to 206 arranged at a position shifted by about 90 ° from the optical axis by the right rotation of the diaphragm ring 208 operate so as to open the opening without interfering with each other. This is possible (see FIGS. 4 to 9). In addition, the opening amount of the opening can be controlled by detecting the rotational position of the aperture ring 208 by a position sensor (not shown) and controlling the driving amount of the motor.

  Further, when retracting or when closing the opening for reducing the exposure amount, the aperture ring 208 is rotated counterclockwise so that the curved portions of the respective aperture blades 203 to 206 do not interfere with each other and the opening is closed. Operation is possible.

  According to the diaphragm device of the above embodiment, the diaphragm blades 203 to 206 have a curved surface shape, and the curved surface shape of the diaphragm blades 203 to 206 is on the diaphragm device side of at least one of the first group lens 101 and the second group lens A201. It is almost the same as the curved surface shape. According to this configuration, it is possible to reduce the distance between the lens curved surface and the aperture blade when retracted, and the lens barrel can be made thin.

  Further, the diaphragm device in the present embodiment is composed of four diaphragm blades 203 to 206, each of which has an operation direction of approximately 90 ° and is operated in opposition to the vertical direction. The two diaphragm blades 203 and 204 are operated to face each other. And the movement timing of the diaphragm blades operating in the vertical direction and the diaphragm blades operating in the horizontal direction, or The amount of movement is different.

  According to this configuration, since the aperture shape is configured by the four aperture blades having a phase shift of approximately 90 ° with respect to the optical axis, the aperture shape can be made polygonal, and the blur can be obtained well. Furthermore, the interference between the diaphragm blades can be prevented by shifting the operation timing of the diaphragm blades in the vertical direction and the left-right direction or by changing the movement amount.

  Further, the diaphragm device in the present embodiment includes a diaphragm ring 208 having four cam groove portions 208a to 208d for fitting with four diaphragm blades 203 to 206 and operating the diaphragm blades 203 to 206 by a predetermined amount. I have. The two cam groove portions 208c and 208d for moving the two diaphragm blades 205 and 206 in the vertical direction have substantially the same shape, and the two cam groove portions for moving the two diaphragm blades 203 and 204 in the left and right direction, respectively. 208a and 208b have substantially the same shape. In this way, the cam groove part that moves the diaphragm blades in the vertical direction and the cam groove part that moves the diaphragm blades in the left-right direction have different shapes, so that the two diaphragm blades that operate in the vertical direction operate in the left-right direction. The movement timing or movement amount of the two diaphragm blades to be different is different.

  According to this configuration, by appropriately forming the shape of the four cam groove portions of one diaphragm ring, the movement timing or movement amount of the four diaphragm blades is controlled, and the diaphragm opening is prevented while preventing interference between the blades. The aperture can be controlled with high accuracy.

  The first group lens 101 and the second group lens (210, 202) have a part of each lens inserted in the optical axis direction when the optical total length becomes the shortest (the concave surface and the convex surface overlap), and the blade Becomes the minimum aperture state. According to this configuration, the lens barrel can be thinned most when retracted, and the diaphragm blades are in the minimum diaphragm or fully closed state. Therefore, it is possible to prevent an adverse effect due to incidence of harmful light on an image sensor such as a CCD during non-photographing.

  As described above, the total length of the lens barrel when retracted can be shortened without degrading the performance of the optical system or increasing the diameter of the lens barrel compared to the conventional retractable lens barrel. In addition, since the diaphragm blades are in the minimum aperture or fully closed state, it is possible to prevent adverse effects due to harmful light incident on an image sensor such as a CCD during non-photographing, a barrier for preventing harmful light incidence, etc. The light shielding means may not be required separately.

  In the present embodiment, the configuration is described in which the fully-closed state is not set at the time of the minimum aperture, but the fully-closed state is also possible. In that case, the operation planes of the four diaphragm blades may be made different so that the four diaphragm blades overlap in the optical axis direction and cover the opening in the fully closed state. However, in this case, in order to avoid interference between the diaphragm blades and the lens, the collapsible length increases by an amount increased by overlapping the diaphragm blades in the optical axis direction.

  In this embodiment, the number of aperture blades is four, but the present invention is not limited to this. For example, when the lens barrel is retracted, it is composed of a single diaphragm blade having a substantially identical curved surface in the gap curved surface between the first lens group and the second lens group, and having a small-diameter opening at the center of the optical axis. When the distance between the second lens group and the second group lens is widened, the diaphragm blades may be moved. However, there are only two types of aperture selection, full open and small aperture.

  Of course, it is possible to make up with two or more diaphragm blades. The curved surface portion of the diaphragm blades has substantially the same curved surface portion in the clearance curved surface portion of the first lens group and the second lens group when retracted. It is also possible to have And when the space | interval of a 1st group lens and a 2nd group lens spreads in imaging | photography state, while allowing a several aperture blade to move within the plane perpendicular | vertical to an optical axis, the curved surface part of a mutual aperture blade does not interfere. Thus, the movement amount may be appropriately controlled.

  According to this configuration, by controlling the movement amount of the aperture blade, the aperture opening can be set in a plurality of stages, and the accuracy of exposure control can be improved.

  However, in the case of three diaphragm blades, if the movement amount of each diaphragm blade is changed to prevent the curved surface portions of each diaphragm blade from interfering with each other, the shape of the diaphragm aperture is distorted. There is a possibility. Moreover, when it comprises a plurality of four or more diaphragm blades, there is a possibility that the control for avoiding the interference of the curved surface portions of the respective diaphragm blades may be complicated. Therefore, in order to realize the diaphragm device of the present invention relatively easily, the configuration of two or four diaphragm blades is preferable.

  The diaphragm device in the present embodiment increases the space efficiency when retracted by disposing light quantity adjusting blades having a curved surface shape that approximates the curved surface shape of a lens having a concave surface or a convex surface on the front or back or one side thereof. It is intended. Therefore, it is not limited to the shape of the concave and convex portions of the lens, and the position of the diaphragm device is not limited, and is a device for limiting unnecessary light (adjusting the passing light beam) for the purpose of a barrier or mask. As a matter of course, it may be arranged other than the original optical ideal aperture position.

  The diaphragm device in this embodiment is not limited to a lens barrel for a digital camera as described above. For example, it may be mounted on an optical apparatus using various image pickup devices such as a video camera and a mobile phone, or may be used as an aperture device for a film camera.

  Of course, it is possible to make the aperture fully closed when the aperture blades are closed, so that both the aperture function and the shutter function can be achieved as a mechanical shutter.

101 1st group lens 102 1st group lens frame 201 2nd group lens A
202 2 group lens B
203 Diaphragm blade 204 Diaphragm blade 205 Diaphragm blade 206 Diaphragm blade 207 Second lens group frame 208 Diaphragm ring 210 Motor 211 Blade cover plate 301 Third lens group 302 Third lens group frame

The present invention relates to a light amount adjusting device such as an aperture device , an optical apparatus, and an imaging device including these devices .

(Object of invention)
An object of the present invention is to provide a light amount adjusting device and an optical apparatus that can achieve a reduction in thickness and a reduction in diameter in the thickness direction in the optical axis direction, and an imaging device including these devices .

In order to achieve the above object, a light amount adjusting device of the present invention is a light amount adjusting device disposed between a first optical member having a concave portion and a second optical member having a convex portion. , At least one blade member, a ring member that rotates around the optical axis to open and close the blade member to change a passing light flux amount, and a driving unit that drives the ring member, The light amount adjusting device is characterized in that a curved shape portion is formed so as to enter at least the concave shape portion of the first optical member or the convex shape portion of the second optical member. It is.

ADVANTAGE OF THE INVENTION According to this invention, the light quantity adjustment apparatus which can achieve thickness reduction and diameter reduction of the thickness direction of an optical axis direction , an optical instrument, and the imaging device provided with these apparatuses can be provided.

Further, the diaphragm device in the present embodiment is composed of four diaphragm blades 203 to 206, each of which has an operation direction of approximately 90 ° and is operated in opposition to the vertical direction. The two diaphragm blades 203 and 204 are operated to face each other. The timing for moving diaphragm blades which operate as diaphragm blades which operate in the vertical direction to the horizontal direction, or the amount of movement is different.

The first group lens 101 and the second group lens ( 201 , 202) have a part of each lens inserted in the optical axis direction when the optical total length becomes the shortest (the concave surface and the convex surface overlap), and the blade Becomes the minimum aperture state. According to this configuration, the lens barrel can be thinned most when retracted, and the diaphragm blades are in the minimum diaphragm or fully closed state. Therefore, it is possible to prevent an adverse effect due to incidence of harmful light on an image sensor such as a CCD during non-photographing.

Claims (6)

At least one blade member;
Driving means for opening and closing the blade member in a direction perpendicular to the optical axis and changing the amount of light flux passing through;
A light amount adjusting device in which the blade member is disposed between the first and second optical members,
The blade member is disposed between the first optical member and the second optical member in a state where the second optical member enters a part of the first optical member. Light quantity adjustment device.   At least a part of the blade member has a curved surface shape, and the curved surface shape is substantially the same shape as the curved surface shape on the blade member side of at least one of the first optical member and the second optical member. The light quantity adjusting device according to claim 1.   The blade member is composed of at least two pairs of blade members, and opens and closes in a second direction that is 90 degrees different from the first direction, and a pair of blade members that open and close in a first direction orthogonal to the optical axis. The light quantity adjusting device according to claim 1, wherein the movement timing or the movement amount of the other pair of blade members is different.   When the first optical member and the second optical member are moved in the optical axis direction so that the optical total length is the shortest, the blade member has a minimum amount of passing light flux or all the light fluxes. 4. The light amount adjusting device according to claim 1, wherein the light amount adjusting device is in a shielded state.   A lens barrel comprising the light amount adjusting device according to any one of claims 1 to 4.   An imaging apparatus comprising the lens barrel according to claim 5.

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