JP2008122712A - Light quantity adjusting device and optical equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light quantity adjusting device capable of obtaining a pupil time-division function with compact constitution. <P>SOLUTION: The light quantity adjusting device 7 includes: a substrate 21 having a fixed aperture 21-a through which light is made to pass; first and second light shielding members 22 and 23 forming a variable aperture AP through which the light is made to pass; and first and second actuators 24 and 26 respectively moving the first and the second light shielding members relative to the substrate. In view in a light passing direction, at least a part of the first and the second actuators is arranged within a range equal to or under the diameter of the fixed aperture from the center of the fixed aperture. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light amount adjusting device having a so-called pupil time division function and an optical apparatus such as an interchangeable lens and a camera provided with the same.

  By shifting the light passage aperture in the direction orthogonal to the optical axis at the pupil position of the photographic optical system, two subject images having different positions are formed in time division on the image plane, and based on the shift amount (phase difference) between the two images. Optical devices that perform autofocus (pupil time division AF) are known.

  In order to perform such pupil time division, there is a method of using a light shielding blade of a light amount adjusting device for originally adjusting a photographing light amount (see Patent Document 1).

The light amount adjusting device disclosed in Patent Document 1 has two light shielding members and two actuators for driving them. Each light shielding member is formed with a spur tooth portion, and the output gear of each actuator is engaged therewith. By moving the two light shielding members in the same direction in the left-right direction by the two actuators, the opening formed by the two light shielding members is shifted in the left-right direction. Further, by moving the two light shielding members in opposite directions, the size of the opening changes and the light quantity is adjusted.
JP 2004-038114 (paragraphs 0025 to 0027, FIG. 2, etc.)

  However, the light amount adjusting device disclosed in Patent Document 1 has a configuration in which two actuators are simply arranged side by side below the two light shielding members. For this reason, the area of the device in the optical axis direction view (light passage direction view) increases. Therefore, miniaturization of an optical device equipped with this light amount adjusting device is hindered.

  In the light amount adjusting device disclosed in Patent Document 1, the light shielding member and the actuator are connected by a gear mechanism. For this reason, noise is likely to occur during operation. Further, the shift position of the opening is likely to vary due to the backlash of the gear, and there is a possibility that the detection accuracy of the phase difference, that is, the autofocus accuracy may be deteriorated.

  Accordingly, an object of the present invention is to provide a light amount adjusting device capable of realizing a pupil time division function with a compact configuration and an optical apparatus including the same.

  A light amount adjusting device according to one aspect of the present invention includes a substrate having a fixed opening that allows light to pass through, first and second light blocking members that form a variable opening that allows light to pass through, and first and second light blocking members. And first and second actuators for respectively moving the actuator with respect to the substrate. Then, when viewed in the light passing direction, at least a part of the first and second actuators is disposed within a range not more than the diameter of the fixed opening from the center of the fixed opening.

  Moreover, the optical apparatus provided with the said light quantity adjustment apparatus comprises the other side surface of this invention.

  According to the present invention, by appropriately setting the relationship between the arrangement area of the first and second actuators and the fixed aperture, the light amount adjustment device having a pupil time division function while being compact, and the compact equipped with the same An optical device can be realized.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  1 and 2 show the configuration of a video camera that is Embodiment 1 of the present invention. The video camera as the optical apparatus of the present embodiment has a photographing optical system as a variable magnification optical system having four lens units that are convex and concave from the object side. FIG. 1 is an exploded perspective view of a video camera, and FIG. 2 is a main sectional view thereof.

  In these drawings, in order from the object side, L1 is a fixed first lens unit, L2 is a second lens unit that performs zooming by moving in the optical axis direction, L3 is a fixed third lens unit, and L4 is a light beam. This is a fourth lens unit that moves in the axial direction to adjust the focus.

  Reference numeral 1 denotes a front lens barrel that holds the first lens unit L1, and reference numeral 2 denotes a zoom movement frame that holds the second lens unit L2. Reference numeral 3 denotes a fixed lens barrel in which a third lens barrel that holds the third lens unit L3 is integrated. Reference numeral 4 denotes a focus movement frame that holds the fourth lens unit.

  Reference numeral 5 denotes an image sensor holder to which the image sensor 6 such as a CCD sensor or a CMOS sensor is fixed.

  The front lens barrel 1 is coupled to the fixed barrel 3 from the front by three screws. The image sensor holder 5 is coupled to the fixed barrel 3 from behind with three screws.

  Reference numeral 7 denotes a light amount adjusting unit (light amount adjusting device). The light quantity adjusting unit 7 forms an opening (variable opening) through which light passes by two diaphragm blades (light shielding members) 7a and 7b. The light amount adjustment unit 7 moves the diaphragm blades 7a and 7b in the opposite directions in the vertical direction (first direction) in the figure by the first and second diaphragm motors 7c and 7d configured by a galvanometer or the like. , Has a function of changing the opening diameter. The light quantity adjustment unit 7 is a so-called guillotine type light quantity adjustment unit.

  Further, the light quantity adjusting unit 7 moves the aperture blades 7a and 7b in the same direction by the first and second aperture motors 7c and 7d, so that the aperture formed by the aperture blades 7a and 7b is changed to the aperture. It has a function of moving to a different position within the plane. These functions will be described later. The light amount adjustment unit 7 is disposed at or near the pupil position of the photographing optical system.

  In FIG. 1, reference numerals 8 and 9 denote guide bars whose both ends are held by a fixed lens barrel 3 and a front lens barrel 1. Reference numerals 10 and 11 denote guide bars whose both ends are held by the fixed barrel 3 and the image sensor holder 5.

  The zoom movement frame 2 is supported by guide bars 8 and 9 so as to be movable in the optical axis direction. The focus moving frame 4 is supported by the guide bars 10 and 11 so as to be movable in the optical axis direction. The zoom movement frame 2 and the focus movement frame 4 have sleeve portions 2a and 4a each having a specific length in the optical axis direction, and each sleeve portion can be moved to one guide bar in the optical axis direction. Engage. Thereby, the fall of each moving frame in the optical axis direction is prevented. Each moving frame has a U-groove, and the U-groove engages with the other guide bar. Thereby, the rotation of each moving frame around the one guide bar is prevented.

  Reference numerals 12 and 13 denote a zoom reset switch and a focus reset switch which are constituted by photo interrupters. These reset switches 12 and 13 optically detect the switching between the light shielding state and the light transmitting state due to the movement of the light shielding portions 2b and 4b formed in the zoom movement frame 2 and the focus movement frame 4 in the optical axis direction, respectively. It is possible to detect whether or not the second and fourth lens units L2 and L4 are positioned at the reference positions for measuring the movement amounts based on the output changes from the reset switches 12 and 13, respectively.

  The zoom reset switch 12 and the focus reset switch 13 are each fixed to the fixed barrel 3 with screws through a reinforcing plate.

  Reference numeral 14 denotes a stepping motor (hereinafter referred to as a zoom motor) as an actuator for moving the second lens unit L2 in the optical axis direction. Reference numeral 15 denotes a stepping motor (hereinafter referred to as a focus motor) as an actuator that moves the fourth lens unit L4 in the optical axis direction.

  Lead screws are formed on the output shafts of the zoom motor 14 and the focus motor 15, respectively. Each of the zoom motor 14 and the focus motor 15 is fixed to the fixed barrel 3 by two screws and one hooking portion (not shown).

  Reference numerals 16 and 17 denote racks, which are attached to the zoom and focus movement frames 2 and 4. These racks 16 and 17 mesh with the lead screws of the zoom motor 14 and the focus motor 15, respectively. When the zoom motor 14 and the focus motor 15 are rotated, the rotational force of the screw is converted into the driving force in the optical axis direction by the racks 16 and 17. Thereby, the zoom movement frame 2 and the focus movement frame 4 are driven in the optical axis direction.

  Reference numerals 18 and 19 denote coil springs that bias the racks 16 and 17 toward one side in the optical axis direction with respect to the zoom and focus moving frames 2 and 4 respectively. The coil springs 18 and 19 also have a function of urging the racks 16 and 17 in the direction of meshing with the lead screws.

  FIG. 7 shows the electrical configuration of the video camera of this embodiment. In addition, the same code | symbol as FIG.1 and FIG.2 is attached | subjected to what is common in the component in FIG.1 and FIG.2.

  Reference numeral 225 denotes a zoom encoder for detecting the position of the second lens unit L2 as a variator in the optical axis direction. Reference numeral 227 denotes a focus encoder for detecting the position of the fourth lens unit L4 in the optical axis direction. These encoders detect the positions (movement amount = number of drive pulses) in the optical axis direction of the second and fourth lens units L2 and L4 from the reference positions detected by the zoom and focus reset switches 12 and 13, respectively. .

  The zoom motor 14 and the focus motor 15 are not limited to the stepping motor described above, and a DC motor or a vibration type motor in which vibration is excited by electro-mechanical energy conversion can also be used. Further, in order to detect the positions of the second and fourth lens units L2 and L4, a position detector other than the encoder may be used.

  Reference numeral 226 denotes a diaphragm encoder, which can be of a type in which a hall element is arranged inside the first and second diaphragm motors 7c and 7d and a rotational positional relationship between the rotor and the stator is detected. . Note that an ND filter (not shown) is attached to the aperture blades 7a and 7b in order to prevent image quality deterioration due to so-called small aperture diffraction. However, the ND filter may be provided independently of the diaphragm blades 7a and 7b, and the ND filter may be put into and out of the optical path by a dedicated motor.

  A camera signal processing circuit 228 performs amplification processing, gamma correction processing, and the like on the output from the image sensor 6. The video signal generated through these processes is displayed on a display (not shown) or recorded on a recording medium (not shown) (semiconductor memory, optical disk, hard disk, magnetic tape, etc.).

  Also, the luminance signal Y of the video signal is input to an AE (automatic exposure) gate 229, an AF (autofocus) gate 230, and a phase difference AF circuit 250. The AE gate 229 and the AF gate 230 set an optimum signal extraction range for exposure determination and focusing in the entire screen. The size of the signal extraction range by these gates 229 and 230 may be variable, or a plurality of gates may be provided.

  Reference numeral 231 denotes an AF signal processing circuit that generates a signal used for TV-AF. The AF signal processing circuit 231 generates one or a plurality of AF evaluation value signals related to high frequency components of the video signal according to the number of AF gates 230.

  The phase difference AF circuit 250 calculates a shift amount of the subject image (luminance signal) acquired in each state where the opening (center) of the light amount adjustment unit 7 is moved to a different position, that is, a phase difference. Information on the calculated phase difference is output to the CPU 232. The video camera of this embodiment can also take a still image. Then, AF (pupil time division AF) is performed in a phase difference detection method using this phase difference information in still image shooting that requires an AF operation faster than TV-AF. However, when fast AF is required even in moving image shooting, pupil time-division AF using the phase difference information may be performed.

  A zoom switch 233 outputs a zoom command to the CPU 232 as a controller in accordance with a user operation.

  Reference numeral 234 denotes a zoom tracking memory, which stores position information of the fourth lens unit L4 for maintaining focus on the subject distance and the position of the second lens unit L2 during zooming. A memory in the CPU 232 may be used as the zoom tracking memory.

  When the zoom switch 233 is operated, the CPU 232 performs the following operations. The CPU 232 is based on the position information (memory position) in the zoom tracking memory 234, so that the second and fourth lens units L2, L4 maintain a specific positional relationship according to the subject distance. Move. That is, the position of the focus motor 15 is adjusted so that the position of the fourth lens unit L4 obtained by the focus encoder 227 matches the movement position of the second lens unit L2 obtained by the zoom encoder 225 and the memory position corresponding to the subject distance. Control the drive.

  In the TV-AF operation, the CPU 232 controls the drive of the focus motor 15 so that the AF evaluation value from the AF signal processing circuit 231 has a peak value.

  Further, the CPU 232 obtains the defocus amount for the subject based on the phase difference information input from the phase difference AF circuit 250, and further calculates the drive amount from the defocus amount to the in-focus position of the fourth lens unit L4. To do. Then, the drive of the focus motor 15 is controlled so that the fourth lens unit L4 reaches the in-focus position.

  Further, the CPU 232 controls the driving of the first and second aperture motors 7c and 7d so that the average value of the luminance signal Y that has passed through the AE gate 229 becomes a value for obtaining proper exposure, so that the aperture diameter is reduced. Control.

  Next, the configuration and function of the light amount adjustment unit 7 in this embodiment will be described with reference to FIGS. 3A, 3B, and 4. FIG.

  FIG. 3A is a view of the light amount adjustment unit 7 as seen from obliquely above after being disassembled in the optical axis direction.

  Reference numeral 21 denotes a base member (substrate) of the light quantity adjustment unit 7. The base member 21 includes a fixed opening 21-a, pin-shaped portions 21-b, 21-c, 21-d and 21-e, arc holes 21-f and 21-g, and a protrusion-shaped portion 21-. h, 21-i are formed.

  Reference numeral 22 denotes a first diaphragm blade (one of 7a and 7b shown in FIGS. 2 and 7). The first aperture blade 22 is formed with a long slot 22-a for guiding linear reciprocation in the directions of arrows A and B in the drawing and a long hole 22-b for receiving a driving force. Yes.

  Reference numeral 23 denotes a second diaphragm blade (the other of 7a and 7b shown in FIGS. 2 and 7). The second aperture blade 23 is formed with an elongated slot 23-a for guiding linear reciprocation in the directions of arrows A and B and an elongated hole 23-b for receiving a driving force.

  Reference numeral 24 denotes a first aperture motor (7c shown in FIGS. 1 and 7) as an actuator.

  A lever member 25 rotates so as to transmit the rotational driving force of the aperture motor 24 to the first aperture blade 22. An interlocking pin 25-a is formed at the tip of the lever member 25.

  Reference numeral 26 denotes a second diaphragm motor (7d shown in FIGS. 1 and 7) as an actuator.

  Reference numeral 27 denotes a lever member that rotates to transmit the driving force of the second aperture motor 26 to the second aperture blade 23. An interlocking pin 27-a is formed at the tip of the lever member 27.

  Reference numeral 28 denotes a pressing plate for holding the first and second aperture blades 22 and 23. The holding plate 28 includes a fixed opening 28-a having the same inner diameter as the fixed opening 21-a of the base member 21 (substrate), and holes 28-b, 28-c, 28-d, 28-e. In addition, arc holes 28-f and 28-g and bent portions 28-h and 28-i are formed. The presser plate 28 is attached to the base member 21 by the bent shape portions 28-h and 28-i engaging with the protruding shape portions 21-h and 21-i of the base member 21.

  AXL is the central axis of the light quantity adjusting unit 7 and coincides with the optical axis of the photographing optical system when incorporated in the photographing optical system. The central axis AXL is an axis passing through the centers of the fixed openings 21-a and 28-a. In a state where the aperture (variable aperture) AP formed by the aperture blades 22 and 23 is changed by the aperture motor 24, that is, in the light amount adjustment state, the center of the variable aperture AP is set on the central axis AXL. In the following description, the central axis AXL is referred to as the optical axis of the light amount adjustment unit 7 for convenience.

  FIG. 3B is a diagram of the light amount adjustment unit 7 in an assembled state as viewed obliquely from above. In FIG. 3B, the pressing plate 28 is omitted.

  The pin-shaped portions 21-b and 21-c of the base member 21 are inserted into the long slot 22-a of the first aperture blade 22. Further, in the elongated hole 22-b of the first aperture blade 22, an interlocking pin 25-a provided at the tip of the lever member 25 that is rotationally driven by the aperture motor 24 is connected to the arc hole 21-f of the base member 21. Is inserted through.

  The pin-shaped portions 21-d and 21-e of the base member 21 are inserted into the long slot 23-a of the second aperture blade 23. Further, in the elongated hole 23-b of the second aperture blade 23, an interlocking pin 27-a provided at the tip of the lever member 27 that is rotationally driven by the second aperture motor 26 is connected to the arc hole of the base member 21. It is inserted through 21-g.

  With such a configuration, the rotational driving force of the first and second aperture motors 24 and 26 is transmitted to the first and second aperture blades 22 and 23 via the lever members 25 and 27, respectively, which are independent of each other. Can be moved.

  By moving the first and second aperture blades 22 and 23 in opposite directions, the diameter of the variable aperture AP formed by them can be changed to adjust the amount of light. Further, by moving the first and second aperture blades 22 and 23 in the same direction, a variable aperture (for example, aperture in a small aperture state) AP is formed in a plane including the aperture (FIG. 4A described later). It can be moved to different positions on the left and right in FIG. 4E.

  4A to 4E respectively show a front view, a side view, and a rear view of the light amount adjustment unit 7 shown in FIG. 3B. From FIG. 4A to FIG. 4E, the states of the diaphragm blades 22 and 23 (the state of the variable aperture AP) change as follows.

  4A shows the open state, FIG. 4B shows the small stop state (the small stop aperture AP ′ is on the optical axis AXL), and FIG. 4C shows the close state. 4D shows a small stop state (small stop aperture AP ′ is on the left side of the optical axis AXL), and FIG. 4E shows a small stop state (small stop aperture AP ′ is on the right side of the optical axis AXL).

  4A to 4C show the light amount adjustment state described above. On the other hand, FIGS. 4D and 4E show pupil time-division states in which the center of the small aperture AP ′ has moved to the left and right by the movement amounts DL and DR, that is, moved to both sides of the optical axis AXL. is there.

  Here, an image obtained through the image sensor 6 in a state where the small aperture AP ′ is moved left and right from the optical axis AXL is used for the above-described pupil time division AF.

  The pupil time division AF will be described in detail below. For this AF, it is particularly effective to use an image sensor capable of high-speed image processing such as a CMOS sensor.

  In normal video output, the output of one image is 1/60 second in the NTSC system. The CMOS sensor as the image sensor 6 of this embodiment can perform high-speed reading, and can capture a plurality of images during one image output. For example, six images can be sequentially captured in 1/60 second.

  As one of the six images in this case, the small aperture aperture AP ′ is moved to the left by the movement amount DL with respect to the optical axis AXL during a time period in which 1/60 second is reduced to 1/6. The first phase difference detection image is captured. Further, as another one of the above six images, the small aperture AP ′ is moved to the right by the movement amount DR with respect to the optical axis AXL during a time period that is 1 / 6th of 1 / 60th of a second. Then, the second phase difference detection image is captured.

  The other four images are taken in with the small aperture AP ′ positioned on the optical axis AXL, and these four images are combined into an output image.

  When the small aperture aperture AP ′ is shifted to the left and right with respect to the optical axis AXL, the center of the subject luminous flux at the pupil position is shifted with respect to the optical axis AXL. A shift corresponding to the degree of out-of-focus occurs in two phase difference detection images.

  Therefore, by obtaining the shift amount (phase difference) between the two phase difference detection images by the phase difference AF circuit 250, the CPU 232 can calculate the defocus amount from the shift amount. Then, the CPU 232 can obtain focus by controlling the fourth lens unit L4 (focus motor 15) based on the defocus amount. In particular, by using a CMOS sensor as the imaging device 6, high-speed and high-performance AF can be realized.

  Here, the arrangement conditions of the first and second aperture motors 24 and 26 in the light amount adjustment unit 7 will be described with reference to FIG. 4A. Here, as shown in FIG. 4A, the first and second apertures when the light amount adjustment unit 7 is viewed from the optical axis direction, in other words, when the light amount adjustment unit 7 is viewed from the direction in which light passes. The arrangement of the motors 24 and 26 will be described.

  In the light amount adjustment unit 7 of the present embodiment, the first and second aperture motors 24 and 26 are arranged at positions symmetrical with respect to the optical axis AXL. However, the lever members 25 and 27 are arranged so as to be point-symmetric with respect to the center O of the fixed opening 21-a through which the optical axis AXL passes.

  1) First, at least a part of the first and second aperture motors 24 and 26 is within a range from the center O of the fixed opening 21-a to the diameter (= 2 × radius R) of the fixed opening 21-a. Is placed inside. In other words, the dimension a from the end of each fixed motor 21-a on the side of each diaphragm motor to the end of each fixed motor 21-a on the side of the fixed opening 21-a is equal to or less than the radius R of the fixed opening 21-a (a ≦ R). As shown in FIG. 4A, it is more preferable that a <R.

  2) Further, the first and second aperture motors 24 and 26 are in a range from the center O of the fixed opening 21-a to twice the diameter of the fixed opening 21-a (= 2 × 2 × radius R). Is placed inside. In this embodiment, as shown in FIG. 4A, the lever members 25 and 27 are arranged to rotate within this range, but at least the first and second aperture motors 24 and 26 are within this range. I just need it.

  3) Then, as shown in FIG. 4A, the first and second aperture motors 24 and 26 respectively overlap the first and second light shielding members 22 and 23 that have been moved to a position where the variable aperture AP is opened. Arranged in the area.

  By satisfying the above arrangement conditions, each aperture motor can be arranged in a region near the fixed opening 21-a of the base member 21 so as not to protrude from the base member 21. Accordingly, a compact light amount adjusting unit 7 having a small area in the optical axis direction view (light passage direction view) can be realized while having the two aperture motors 24 and 26. In this case, an antireflection treatment (application of an antireflection paint) may be performed on the outer peripheral surface of each aperture motor so that the light beam does not undergo unnecessary reflection in the region on the fixed opening 21-a side. .

  In addition, the diaphragm motors 24 and 26 may be arranged so as to be asymmetric with respect to the optical axis AXL within a range that satisfies the above arrangement conditions. Further, the two lever members 25 and 27 may be arranged on one side (upper side or lower side in FIG. 4A) of the light quantity adjustment unit.

  Further, in the light quantity adjustment unit of the present embodiment, the diaphragm member and the lever member that transmits the driving force of the diaphragm motor are connected by the engagement of the pin and the elongated hole, so that the operation sound is higher than when using a gear. It is small and the positioning accuracy of the aperture blade can be increased. For this reason, the position error of the aperture formed in the pupil time division state can be reduced. Therefore, highly accurate pupil time division AF can be performed.

  5A, 5B, and 6 show a light amount adjustment unit that is Embodiment 2 of the present invention. This light quantity adjustment unit 7 'is mounted on the video camera described in the first embodiment. FIG. 5A is a diagram in which the light amount adjustment unit is disassembled in the optical axis direction and is viewed from obliquely above.

  Reference numeral 31 denotes a base member of the light quantity adjustment unit 7 '. The base member 31 has an open opening 31-a, groove-shaped portions 31-b and 31-c, and protrusion-shaped portions 31-h and 31-i.

  Reference numeral 32 denotes a first diaphragm blade, in which holes 32-a and 32-b for receiving a linear reciprocating driving force in the directions of arrows A and B in the figure are formed.

  Reference numeral 33 denotes a second diaphragm blade, in which holes 33-a and 33-b for receiving a linear reciprocating driving force in the directions of arrows A and B are formed.

  Reference numeral 34 denotes a first vibrator as a vibrating member constituted by a piezoelectric element or the like. The first vibrator 34 is excited to vibrate by applying a frequency voltage (pulse voltage or the like). For this reason, the first slider 35 can be driven in the directions of arrows A and B by bringing the first slider 35 as a contact member into contact with the first vibrator 34.

  The pin portions 35-a and 35-b formed on the first slider 35 are inserted into the holes 32-a and 32-b of the first aperture blade 32. Thereby, the first aperture blade 32 can be driven in the directions of arrows A and B together with the first slider 35. The first slider 35 is formed of a magnet, and an appropriate contact pressure between the first slider 35 and the first vibrator 34 is ensured by magnetically attracting the first slider 34. .

  The first vibrator 34 and the first slider 35 constitute a first vibration type linear actuator.

  Reference numeral 36 denotes a second vibrator as a vibrating member constituted by a piezoelectric element or the like. The second vibrator 36 is excited to vibrate by applying a frequency voltage (pulse voltage or the like). For this reason, the second slider 37 can be driven in the directions of arrows A and B by bringing the second slider 37 as a contact member into contact with the second vibrator 36.

  Pin portions 37-a and 37-b formed on the second slider 37 are inserted into the holes 33-a and 33-b of the second aperture blade 33. Thereby, the second aperture blade 33 can be driven in the directions of arrows A and B together with the second slider 37. The second slider 37 is formed of a magnet, and an appropriate contact pressure between the second slider 37 and the second vibrator 36 is ensured by magnetically attracting the second slider 36. .

  The second vibrator 36 and the second slider 37 constitute a second vibration type linear actuator.

  Reference numeral 38 denotes a pressing plate for holding the diaphragm blades 32 and 33, and an open opening 38-a having the same inner diameter as the open opening 31-a of the base member 31 is formed. Further, the holding plate 38 is formed with bent portions 38-h and 38-i. The pressing plate 38 can be attached to the base member 31 by engaging the bent shape portions 38-h and 38-i with the protruding shape portions 31-h and 31-i of the base member 31.

  FIG. 5B is a view of the assembled light amount adjustment unit 7 ′ viewed obliquely from above. In FIG. 5B, the pressing plate 38 is omitted.

  With such a configuration, the driving force of the first and second vibrating linear actuators can be transmitted to the first and second diaphragm blades 32 and 33, respectively, and can be moved independently of each other.

  By moving the first and second aperture blades 32 and 33 in the opposite directions, the diameter of the variable aperture AP formed by them can be changed to adjust the amount of light. Further, by moving the first and second aperture blades 32 and 33 in the same direction, a variable aperture (for example, an aperture in a small aperture state) AP is arranged in a plane including the aperture (FIG. 6A described later). (In the sheet of FIG. 6E), it can be moved to different positions on the left and right.

  6A to 6E respectively show a front view, a side view, and a rear view of the light amount adjustment unit 7 ′ shown in FIG. 5B. From FIG. 6A to FIG. 6E, the state of the diaphragm blades 32 and 33 (the state of the variable aperture AP) changes as follows.

  6A shows an open state, FIG. 6B shows a small stop state (the small stop aperture AP ′ is on the optical axis AXL), and FIG. 6C shows a close state. 6D shows a small stop state (small stop aperture AP ′ is on the left side of the optical axis AXL), and FIG. 6E shows a small stop state (small stop aperture AP ′ is on the right side of the optical axis AXL).

  6A to 6C show the light amount adjustment state described above. On the other hand, FIGS. 6D and 6E show pupil time-division states in which the center of the small aperture AP ′ has moved to the left and right by the movement amounts DL and DR, that is, moved to both sides of the optical axis AXL. is there.

  Also in the present embodiment, an image obtained through the image pickup device 6 in a state where the small aperture AP ′ is moved left and right from the optical axis AXL is used for the above-described pupil time division AF.

  Here, the arrangement of the first and second vibration type linear actuators in the light amount adjustment unit 7 ′ will be described with reference to FIG. 6A. Here, as shown in FIG. 6A, when the light amount adjustment unit 7 'is viewed from the optical axis direction, in other words, when the light amount adjustment unit 7' is viewed from the direction in which light passes through, the first and second light sources. The arrangement of the vibration type actuator will be described.

  In the light quantity adjustment unit 7 'of the present embodiment, the first and second vibration type linear actuators are arranged at point-symmetrical positions with respect to the center O of the fixed opening 21-a through which the optical axis AXL passes. .

  Also in the present embodiment, the same arrangement conditions as in 1) to 3) described in the first embodiment are satisfied. In this case, “diaphragm motor” in the description of the first embodiment may be read as “a vibration type actuator including a vibrator and a slider”.

  According to the present embodiment, the vibration type linear actuator is used as the drive source of the diaphragm blades 32 and 33, so that the convex shape is less in the optical axis direction view and the side view than in the first embodiment using the motor. A compact light quantity adjustment unit can be realized.

  In addition, by using the vibration type linear actuator, it is possible to reduce the operation sound and to accurately control the position of the pupil time-division opening compared to the case where the motor driving force is transmitted to the diaphragm blades with a gear. it can. Therefore, highly accurate pupil time division AF can be performed.

1 is an exploded perspective view of a video camera that is Embodiment 1 of the present invention. 1 is a cross-sectional view of a video camera according to Embodiment 1. FIG. 2 is an exploded perspective view of a light amount adjustment unit mounted on the video camera of Embodiment 1. FIG. FIG. 3 is a perspective view illustrating an assembled state of the light amount adjustment unit according to the first embodiment. The front view, side view, and back view of the light quantity adjustment unit (open state) of Example 1. FIG. FIG. 3 is a front view, a side view, and a rear view of a light amount adjustment unit (small aperture state) according to the first embodiment. FIG. 3 is a front view, a side view, and a rear view of the light amount adjustment unit (closed state) according to the first embodiment. FIG. 3 is a front view, a side view, and a rear view of the light amount adjustment unit (moving the pupil to the left) according to the first embodiment. FIG. 3 is a front view, a side view, and a rear view of the light amount adjustment unit (moving the pupil to the right) according to the first embodiment. The disassembled perspective view of the light quantity adjustment unit mounted in the video camera which is Example 2 of this invention. The perspective view which shows the assembly state of the light quantity adjustment unit of Example 2. FIG. The front view of the light quantity adjustment unit (open state) of Example 2, a side view, and a rear view. The front view, side view, and back view of the light quantity adjustment unit (small aperture state) of Example 2. FIG. The front view of the light quantity adjustment unit (closed state) of Example 2, a side view, and a rear view. FIG. 6 is a front view, a side view, and a rear view of a light amount adjustment unit (moving the pupil to the left) according to the second embodiment. FIG. 6 is a front view, a side view, and a rear view of a light amount adjusting unit (moving the pupil to the right) according to the second embodiment. FIG. 2 is a block diagram illustrating an electric circuit configuration of the video camera according to the first embodiment.

Explanation of symbols

L1 1st lens unit L2 2nd lens unit L3 3rd lens unit L4 4th lens unit 1 Front lens barrel 2 Zoom moving frame 3 Fixed lens barrel 4 Focus moving frame 6 Image sensor 7, 7 'Light quantity adjusting unit 7a, 7b , 22, 23, 32, 33 Aperture blades 7c, 7d, 24, 26 Aperture motor 14 Zoom motor 15 Focus motor 21 Base member 25, 27 Lever member 34, 36 Vibrator 35, 37 Slider 35-a, 35-b Interlocking pin

Claims (8)

A substrate having a fixed aperture through which light passes;
First and second light blocking members that form a variable aperture through which light passes;
First and second actuators for moving the first and second light shielding members with respect to the substrate, respectively;
In the light passing direction view, at least a part of the first and second actuators is disposed within a range not more than the diameter of the fixed opening from the center of the fixed opening.   The said 1st and 2nd actuator is arrange | positioned in the range of 2 times the diameter of this fixed opening from the center of the said fixed opening in the said light passage direction view. Light quantity adjustment device.   3. The light amount adjusting device according to claim 1, wherein the first and second actuators are arranged on both sides of the fixed opening in the light passing direction view.   In the light passing direction view, the first and second actuators are disposed in a region overlapping the first and second light shielding members moved so that the variable opening is in an open state. The light quantity adjusting device according to any one of claims 1 to 3. Each of the first and second actuators is a vibration type actuator having a vibration member in which vibration is excited by electro-mechanical energy conversion, and a contact member in contact with the vibration member,
One of the vibration member and the contact member is attached to the substrate or a member integral with the substrate, and the other is attached to the light shielding member. The light quantity adjustment apparatus of description.   The first and second actuators move the first and second light shielding members so that the center of the variable opening moves to one side and the other side across the center of the fixed opening. The optical apparatus according to any one of claims 1 to 5, characterized in that:   An optical apparatus comprising the light amount adjusting device according to any one of claims 1 to 5. A light amount adjusting device according to claim 6,
The subject image is acquired in a state where the center of the variable aperture moves to one side and the other side across the center of the fixed aperture, and focus control is performed using the subject image. Item 6. The optical instrument according to Item 5.