JP5595060B2 - Light amount adjusting device and imaging device having the same - Google Patents

Description

  The present invention relates to a light amount adjusting device and an imaging device having the same.

  Patent Document 1 discloses an imaging apparatus that drives a diaphragm blade group that serves both as a diaphragm function for exposure adjustment and a shutter function with a single motor.

JP 2003-5248 A

  Since the diaphragm blade of Patent Document 1 has two functions, the thickness in the optical axis direction can be reduced and the size can be reduced as compared with the case where the aperture function for exposure adjustment and the shutter function are configured by separate blades. There is a problem that the shutter operation cannot be performed.

  It is an exemplary object of the present invention to provide a light amount adjusting device and an imaging device having the same that can realize downsizing and high-speed shutter operation.

The light quantity adjusting device of the present invention includes a plurality of light shielding blades, a base member having an opening disposed on the optical axis of the imaging device, a first drive member attached to the base member, and a first member attached to the base member. Two driving members, a first shaft provided on one of the first driving member and each light shielding blade, a first hole provided on the other and into which the first shaft is inserted, and the second driving A second shaft portion provided on one of the member and each light shielding blade, a second hole portion provided on the other and into which the second shaft portion is inserted, and the plurality of light shielding blades centered on the second shaft portion A first driving means for rotating the first driving member so as to change the size of the opening, and the plurality of light shielding blades rotate about the first shaft portion to open and close the opening. The second drive member is rotationally driven so as to be provided separately from the first drive means. Have a, a second drive means which is, the first driving member and the second drive member, the same surface of the base member abuts one of said second driving member and the first drive member, A hollow cylindrical first base; and a first arm portion extending outward from the first base. The other of the first drive member and the second drive member is the first base and the first base. A hollow cylindrical second base having an opening for accommodating a part of the arm and having a notch as a through hole; and a second arm extending outward from the second base, One arm portion protrudes outward from the opening through the notch of the second base .

  According to the present invention, it is possible to provide a light amount adjusting device and an image pickup apparatus having the same that can realize downsizing and high-speed shutter operation.

FIG. 1 is a block diagram of the imaging apparatus of the present embodiment. 2 is an exploded perspective view of the light amount adjusting device shown in FIG. FIGS. 3A to 3C are plan views showing different states of the light amount adjusting device shown in FIG.

  FIG. 1 is a block diagram of the imaging apparatus of the present embodiment. The imaging apparatus includes an imaging optical system, an imaging element 14, a light quantity detection sensor 15, a microcomputer 16, a release button 17, and a light quantity adjustment apparatus 20.

  The imaging optical system includes a fixed lens group 11, a zoom lens group 12 for zooming that can move in the optical axis direction, and a focus lens group 13 for focus adjustment that can move in the optical axis direction. The image sensor 14 photoelectrically converts a subject image (optical image) and outputs an electrical signal (video signal).

  The light quantity detection sensor 15 detects the light quantity from the video signal obtained from the image sensor 14. The microcomputer 16 adjusts exposure by energizing the first motor 80 of the light amount adjusting device 20 in order to maintain the light amount set based on the detection result of the light amount detection sensor 15. Further, the microcomputer 16 conducts a shutter operation by energizing the second motor 86 (or / and the first motor 80) in response to the operation of the release button 17. The release button 17 sets shooting conditions by a half-press operation. The light amount adjusting device 20 is disposed between the variable power lens group 12 and the focus lens group 13 and adjusts the light amount.

  FIG. 2 is an exploded perspective view of the light amount adjusting device 20. The light amount adjusting device 20 includes a base member 21, a diaphragm blade group 30, a first drive ring 40, a second drive ring 50, a presser plate 60, a first drive lever 70, a second drive lever 76, a first motor 80, a second motor. A motor 86 is included.

  The base member 21 includes a holding surface 22, a first ring portion 23, a second ring portion 24, a first motor mounting portion (first mounting portion) 25, and a second motor mounting portion (second mounting portion) 26.

  The holding surface 22 is a hollow circular surface that holds the surfaces of the first drive ring 40 and the second drive ring 50 opposite to the subject side.

  The first ring portion 23 is a ring member having a hollow cylindrical shape that is disposed in the hollow portion of the holding surface 22 and protrudes from the holding surface 22 toward the subject side, and has a circular opening 23 a centered on the optical axis L at the center. The opening 23a is disposed on the optical axis of the imaging device. The inner peripheral surface 43 of the first drive ring 40 is rotatably engaged with the outer peripheral surface 23b of the first ring portion 23.

The second ring portion 24 is provided around the holding surface 22 and protrudes from the holding surface 22 to the subject side. The outer peripheral surface 56 of the second drive ring 50 is rotatably engaged with the inner peripheral surface 24a of the second ring portion 24. The second ring 24, in this embodiment, has a fixed portion 24b which is provided at three positions at 120 ° intervals around the optical axis L, the screw holes 24b ₁ is provided in each fixing portion 24b. A screw 90 is engaged with each screw hole 24b.

  The surfaces of the first ring portion 23 and the second ring portion 24 that are orthogonal to the optical axis L on the subject side have the same height (the same surface), and support the back surface of the presser plate 60 opposite to the subject. The first drive ring 40, the second drive ring 50, and the aperture blade group 30 are located in the space between the surface of the first ring portion 23 and the second ring portion 24 (the back surface of the pressing plate 60) and the holding surface 22. Be placed.

  Further, the second ring portion 24 is provided with a first notch 24c and a second notch 24d. The first arm 47 of the first drive ring 40 is disposed across the first cutout 24c. The arm portion 57 of the second drive ring 50 is disposed across the second cutout 24d.

  As described above, the second ring portion 24 is cut out at a portion corresponding to the first motor mounting portion 25 such that a part of the first first arm portion 47 is disposed on the first motor mounting portion 25. . Further, a portion corresponding to the first motor mounting portion 26 is cut out so that a part of the second second arm portion 57 is disposed on the second motor mounting portion 26. Thereby, the connection mechanism between the first motor 80 and the first drive ring 40 and the connection mechanism between the second motor 86 and the second drive ring 50 can be simplified.

  In the present embodiment, the rotational range of the first first arm portion 47 is determined by the circumferential length of the first notch 24c, and the rotational range of the second second arm portion 57 is the circumferential direction of the second notch 24d. Is determined by the length of

  The first motor mounting portion 25 is a U-shaped hole for mounting the drive lever 70 and the first motor 80, and is formed on the outer side in the radial direction of the holding surface 22 from the second ring portion 24. The second motor mounting portion 26 is a U-shaped hole for mounting the drive lever 76 and the second motor 86, and is formed on the outer side in the radial direction of the holding surface 22 from the second ring portion 24.

  In this embodiment, the diaphragm blade group 30 includes six (iris) diaphragm blades (a plurality of light shielding blades) 31 and is disposed between the presser plate 60 and the pair of drive rings. The aperture blade group 30 has a light shielding function and provides an exposure adjustment effect and a shutter effect. Since the diaphragm blade group 30 of the present embodiment also serves as an iris diaphragm blade and a shutter blade, it is possible to reduce the thickness of the image pickup apparatus by reducing the thickness in the optical axis direction compared to the case where both are constituted by separate blade groups. Can do.

  Each diaphragm blade 31 has a substantially T-shaped identical configuration, a first hole portion 32 having a long hole shape, and a second hole portion 33 provided outside the first hole portion 32 and having a cylindrical shape. Have. The shapes of the second hole portion 33 and the second hole portion are merely examples, and other shapes such as a cam shape can be taken. The diaphragm blade group 30 is arranged so that a part thereof overlaps in the clockwise direction in order.

  A first shaft 45 (to be described later) of the first drive ring 40 is inserted into the first hole 32 and engaged therewith. A second shaft 55 (described later) of the second drive ring 50 is inserted into the second hole 33 and engaged therewith. However, the relationship between the hole and the shaft may be reversed.

  That is, it is only necessary that the first shaft part is provided on one of the first driving member 40 and each light shielding blade 31 and the first hole part into which the first shaft part is inserted is provided on the other. Further, the second shaft part may be provided in one of the second drive member 50 and each light shielding blade 31 and the second hole part 33 into which the second shaft part 55 is inserted may be provided in the other. As a result, the plurality of light shielding blades 31 rotate about the second shaft portion 55 to change the size of the opening 23a, and the plurality of light shielding blades 31 rotate about the first shaft portion 45 to open and close the opening 23a. To do.

  The first drive ring (first drive member) 40 is attached to the base member 21, and has a hollow disk-shaped or hollow-cylindrical first base 41 and a first arm portion 47 that extends radially outward from the first base 41. And having. In addition, although the 1st drive member of a present Example has a ring shape, as long as the aperture blade group 30 can be driven, the shape is not limited.

  The first base 41 engages with the diaphragm blade group 30 and transmits the driving force from the first motor 80 to the first base 41. The first arm portion 47 is fixed to the first base 41 and receives a rotational driving force from the first motor 80.

  The first base 41 has an opening 42 in the center that exposes the opening 23a slightly larger than the opening 23a, and an inner peripheral surface 43 that defines the opening 42 is rotatably engaged with the outer peripheral surface 23b of the first ring portion 23. (The first ring portion 23 is inserted into the opening 42 and is rotatably engaged).

  On the subject-side surface 44 of the first base 41, six cylindrical first shaft portions 45 are provided around the optical axis L and arranged at equal intervals of 60 °. Each first shaft portion 45 is inserted into and engaged with the first hole portion 32 of each diaphragm blade 31 from the image sensor side (the side opposite to the subject).

  The first base 41 is accommodated in an opening 52 that is a hollow portion of the second base 51 of the second drive ring 50. The first base 41 has an outer peripheral surface 46, and there is a gap (clearance C shown in FIG. 3 described later) between the outer peripheral surface 46 and the inner peripheral surface 53 of the second drive ring 50. Since the rotation of the first base 41 is not affected by the second drive ring 50 due to the clearance C, it is easy to ensure the accuracy of light amount adjustment.

  The first arm portion 47 has a long hole portion 48 at the tip. A cylindrical pin 71 of the first drive lever 70 is inserted into the long hole portion 48. A part of the first arm portion 47 is disposed inside the opening 52 of the second drive ring 50 on the holding surface 22, and a part of the first arm portion 47 is notch 52 of the second drive ring 50 and the second ring portion 24. The first motor mounting portion 25 is disposed so as to protrude outward across the notch 24c.

  The second drive ring (second drive member) 50 is attached to the base member 21, and has a hollow disk-shaped or hollow-cylindrical second base 51 and a second arm portion 57 extending radially outward from the second base 51. And having. Although the second drive member of the present embodiment has a ring shape, the shape is not limited as long as the diaphragm blade group 30 can be driven.

  The second base 51 engages with the aperture blade group 30 and transmits the driving force from the second motor 86 to the second base 51. The second arm portion 57 is fixed to the second base 51 and receives a rotational driving force from the first motor 86.

  The second base 51 has an annular shape that has an opening 52 concentric with the opening 23 a in the center and exposes the opening 23 a, and has a notch 52 a connected to the opening 52 at a part of the annular shape. As a result, the second base 51 has a C shape. A part of the first base 41 and the first arm portion 47 of the first drive ring 40 is disposed in the opening 52.

  A part of the first arm portion 47 of the first drive ring 40 is disposed in the notch 52a, and allows the first arm portion 47 to protrude outward from the opening 52. The circumferential length of the notch 52a is set to a length that does not contact when the first arm portion 47 rotates. Accordingly, the rotation of the first base 41 is not affected by the second drive ring 50, and it is easy to ensure the accuracy of light amount adjustment.

  As described above, the inner peripheral surface 53 that defines the opening 52 is separated from the outer peripheral surface 46 of the first drive ring 40. On the subject-side surface 54 of the second base 51, six cylindrical second shaft portions 55 are provided around the optical axis L and arranged at equal intervals of 60 °. Each second shaft portion 55 is inserted into the second hole portion 33 of each diaphragm blade 31 from the image sensor side and engaged therewith.

  The surface 44 of the first base 41 and the surface 54 of the second base 51 have the same height (level) when the first drive ring 40 and the second drive ring 50 are placed on the holding surface 22. Thus, since the 2nd drive ring 50 accommodates the 1st drive ring 40 inside, the light quantity adjustment apparatus of a present Example can achieve size reduction, without the thickness of an optical axis direction increasing. However, since the size reduction in the optical axis direction has already been achieved by the diaphragm blade group 30, the present invention does not necessarily require that the first drive ring 40 be accommodated in the second drive ring 50, and the surface 44 This does not exclude the configuration in which the contact with the back surface opposite to the front surface 54 is made.

  The second base 51 is disposed inside the second ring portion 24 of the base member 21. The second base 51 has an outer peripheral surface 56, and the outer peripheral surface 56 and the inner peripheral surface 24a of the second ring portion 24 are rotatably engaged.

  The second arm portion 57 has a long hole portion 58 at the tip. A cylindrical pin 77 of the second drive lever 76 is inserted into the long hole portion 58. A part of the second arm part 57 is disposed on the holding surface 22, and a part of the second arm part 57 projects outwardly across the second notch 24 d of the second ring part 24 and is disposed on the second motor mounting part 26. .

  The presser plate 60 presses the diaphragm blade group 30 from above the diaphragm blade group 30 together with the first drive ring 40 and the second drive ring 50 arranged below the diaphragm blade group 30 and fixes the diaphragm blade group 30 to the base member 21. The holding plate 60 has a fixed opening 61 centered on the optical axis L and three holes 62 into which screws 90 are inserted at the center thereof. The presser plate 60 is fixed after being positioned on the base member 21 with the screw 90 inserted into the hole 62.

  The first drive lever 70 is fitted into a hole (not shown) into which the output shaft (motor shaft) 81 of the first motor 80 is inserted and engaged, and a long hole 48 provided in the first drive ring 40. A pin 71 is provided. The first drive lever 70 can rotate the first drive ring 40 around the optical axis when the first motor 80 rotates.

  The second drive lever 76 is fitted into a hole (not shown) into which the output shaft (motor shaft) 87 of the second motor 86 is inserted and engaged, and a long hole 58 provided in the second drive ring 50. It has a pin 77. The second drive lever 76 can rotate the second drive ring 50 around the optical axis when the second motor 86 rotates.

  The first motor 80 is a motor, for example, a stepping motor, serving as a first drive unit that rotationally drives the first drive ring 40 to perform light amount control. The first motor 80 has a magnet (not shown) fixed to the output shaft (motor shaft) 81 by press-fitting or bonding, and finely adjusts the amount of light to generate a rotational force by energizing a coil in the motor. Make it possible. A magnetic sensor such as a Hall element is installed inside the first motor 80 to control the position of the magnet. The first drive lever 70 is fixed to the output shaft 81 by press-fitting or bonding. The first motor 80 is coupled to the base member 21 with a screw or the like (not shown).

  The second motor 86 is a motor as second driving means that rotationally drives the second drive ring 50 to perform a shutter operation. The second motor 86 may also be a stepping motor. The second motor 86 has a magnet fixed to the output shaft 87 by press-fitting or bonding, and realizes a high-speed shutter that generates a rotational force by energizing a coil in the motor. The second motor 86 is coupled to the base member 21 with a screw (not shown) or the like.

  In the present embodiment, a pair of motors (a second motor 86 provided separately from the first motor 80 and the first motor 80) are provided for the diaphragm blade group 30. Therefore, unlike Patent Document 3 in which the diaphragm blade group is rotationally driven by a single motor, a high-speed shutter operation can be performed. The second motor 86 may have a resolution smaller than that of the first motor 80 or the same. Since a motor having a small resolution can be used, the cost of the light amount adjusting device 20 is reduced.

  FIG. 3A to FIG. 3C are plan views of the light amount adjusting device 20 with the presser plate 60 removed.

  FIG. 3A shows a state in which the first arm portion 47 is at the end portion on the opening side of the first notch 24c and the second arm portion 57 is at the end portion on the opening side of the second notch 24d. Yes. The end on the opening side is the end in the direction in which the aperture blade group 30 opens. FIG. 3A shows a state where the diaphragm blade group 30 of the light amount adjusting device 20 is most widely opened.

  3A to 3C, for the first arm 47, the counterclockwise direction is the direction in which the diaphragm blade group 30 opens, and the clockwise direction (R1 direction) is the direction in which the blade group 30 is closed. For the second arm 57, clockwise is the direction in which the aperture blade group 30 opens, and counterclockwise (R2 direction) is the direction in which the blade group 30 is closed.

  The first motor 80 can perform fine exposure control (light amount adjustment) by the microcomputer 16 so as to continuously follow the set light amount with respect to the detection signal that changes every moment from the light amount detection sensor 15.

  From the state shown in FIG. 3A, the rotation of the first motor 80 is transmitted to the first drive ring 40 via the first drive lever 70. When the first drive ring 40 rotates in the direction of the arrow R1, each diaphragm blade 31 rotates about the rotation pin 55 around the optical axis L via the first shaft portion 45 provided in the drive ring 40 and is in an open state. The light amount is adjusted by performing the diaphragm operation from the closed position to the closed position.

  In FIG. 3B, the second arm portion 57 is at the end of the second notch 24d on the opening side, and the first arm portion 47 is at the first notch 24c and the aperture blade group 30 is at the end of the opening side. The state which exists in the intermediate position of the edge part by the side of closing is shown. In FIG. 3B, the aperture blade group 30 of the light amount adjusting device 20 is in a state of being slightly closed from the open state shown in FIG.

  As described above, the second motor 86 is a drive unit for performing a shutter operation for controlling the amount of light accumulated in the image sensor 14 during still image shooting. The second motor 86 needs to be a drive unit that does not require a diaphragm operation such as resting in the middle and that can perform a shutter operation at high speed. When the release button 17 is pressed by the user, as shown in FIGS. 3B and 3A, the second motor 80 is energized to adjust the amount of light according to the photographing conditions.

  FIG. 3C shows a state in which the second arm portion 57 is at the end of the second cutout 24d on the closing side, and the first arm portion 47 is in the position shown in FIG. 3B. In FIG. 3C, the diaphragm blade group 30 of the light amount adjusting device 20 is in a completely closed state.

  The rotation of the second motor 86 is transmitted to the second drive ring 50 via the second drive lever 76. When the second drive ring 50 rotates in the direction of the arrow R2, the diaphragm blade group 30 rotates around the optical axis L around the first shaft portion 45 via the second shaft portion 45 to stop from the open state to the closed state. Perform the shutter operation.

  In order to realize a faster shutter operation, the first motor 80 is operated simultaneously with the second motor 86 to rotate the first drive ring 40 in the direction opposite to the rotation direction of the second drive ring 50 (arrow R2 direction) ( (R1 direction).

  Further, in the case of the shutter operation from the small aperture side, since the rotation amount of the drive arm is reduced, the second motor 86 is not operated and the first motor 80 is not operated when the performance of the aperture drive unit can cope with the high-speed shutter operation. It is possible to perform the shutter operation only by using the shutter. In this case, the first motor 80 is used to completely close the opening from the state in which the plurality of light shielding blades 31 narrow the opening 23a to a set size or less, and the opening 23a is larger than the set size. A second motor 86 is used to close the opening.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  The light amount adjusting device can be widely applied to imaging devices such as a video camera, a photographic camera using a silver salt film, and an electronic camera typified by a digital still camera using an imaging device.

21 Base member 31 Diaphragm blade (light-shielding blade)
32 1st hole part 33 2nd hole part 40 1st drive ring (1st drive member)
45 First shaft portion 50 Second drive ring (second drive member)
55 Second shaft portion 80 First motor (first driving means)
86 Second motor (second drive means)

Claims (8)

A plurality of shading blades;
A base member having an opening disposed on the optical axis of the imaging device;
A first drive member attached to the base member;
A second drive member attached to the base member;
A first shaft provided on one of the first drive member and each light shielding blade; a first hole provided on the other and inserted with the first shaft;
A second shaft provided in one of the second drive member and each light shielding blade, a second hole provided in the other and inserted into the second shaft,
First driving means for rotationally driving the first driving member such that the plurality of light shielding blades rotate about the second shaft portion to change the size of the opening;
Second driving means provided separately from the first driving means for rotating the second driving member so that the plurality of light shielding blades rotate about the first shaft portion to open and close the opening. and, the possess,
The first drive member and the second drive member abut on the same surface of the base member,
One of the first drive member and the second drive member has a hollow cylindrical first base and a first arm portion extending outward from the first base,
The other of the first drive member and the second drive member has a hollow cylindrical second having an opening for accommodating a part of the first base and the first arm portion and having a notch as a through hole. A base and a second arm portion extending outward from the second base;
The first arm portion protrudes outward from the opening through the cutout of the second base . The base member includes a first ring portion having the opening, and a second ring portion exposing the opening larger than the first ring portion,
The first base has an inner peripheral surface that engages with an outer peripheral surface of the first ring portion,
The light quantity adjusting device according to claim 1 , wherein the second base has an outer peripheral surface that engages with an inner peripheral surface of the second ring portion. 3. The light amount adjusting device according to claim 1, wherein a surface of the first base and a surface of the second base have the same height on the side opposite to the same surface of the base member. In order to close the opening from a state in which the plurality of light shielding blades narrows the opening to a set size or less, only the first driving means is used among the first driving means and the second driving means , In order to close the opening from a state where the opening is larger than the set size, only the second driving means among the first driving means and the second driving means, or the first driving means and the first driving means . light quantity adjusting device according to any one of claims 1 to 3, characterized by the use of both 2 drive means. The base member further includes a first mounting portion for mounting the first driving means, and a second mounting portion for mounting the second driving means,
The second ring portion is cut out at a portion corresponding to the first mounting portion so that a portion of the first arm portion is disposed on the first mounting portion, and a portion of the second arm portion is light quantity we are adjusting device according to claim 2, wherein the second portions corresponding to the mounting portion is cut out to be placed in the second mounting part.   2. The light amount adjusting device according to claim 1, wherein when the second driving unit is used, the first driving unit is also used so that the opening and closing of the opening is performed at high speed. The resolution of the second driving means is light quantity adjusting device according to any one of claims 1 to 6, characterized in that less than the resolution of said first driving means. Imaging apparatus characterized by having a light quantity adjusting device according to any one of claims 1 to 7.