Light amount adjusting apparatus and optical apparatus

Abstract

To provide a light quantity adjusting device capable of easily miniaturizing a diaphragm and an optical filter or a shutter.SOLUTION: A light amount adjusting device 100 includes a plurality of diaphragm blades 105 and 106 that move in a plane orthogonal to an optical axis to form an opening smaller than a fixed opening, a driving unit 105 that moves the plurality of diaphragm blades 105 and 106, a light amount adjusting member 114 that moves forward and backward with respect to the fixed opening to adjust a light amount, and a driving unit 114 that operates the light amount adjusting member 114, in which at least two of the plurality of diaphragm blades 105 and 106 operate in a direction connecting the driving unit 108 of the diaphragm and the fixed opening, and the driving unit 102 of the light amount adjusting member is disposed in a direction orthogonal to an operation direction of the diaphragm blades 102 and 106.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a light amount adjusting device mounted on an optical device such as an imaging device or an interchangeable lens, and also to an imaging device equipped with a light amount adjusting device. [Background technology]

[0002] Light quantity adjusting devices mounted on optical equipment such as digital cameras and video cameras include an aperture that uses a stepping motor or the like as a drive unit to rotate aperture blades via a rotating member with gears, thereby changing the area of ​​the light passage opening to adjust the amount of light passing through the device, and a neutral density filter that uses a moving magnet-type electromagnetic drive unit as a drive unit to move in and out of the light passage opening to cover or open it (see Patent Document 1).

[0003] In recent years, optical devices such as still cameras and video cameras equipped with light quantity adjusting devices have become smaller and thinner, and there is a strong demand for light quantity adjusting devices to also become smaller and thinner. SUMMARY OF THE INVENTION An object of the present invention is to provide a light amount adjusting device that is smaller and thinner than conventional products without impairing the characteristics.

[0004] Furthermore, it is preferable that the shape of the diaphragm opening formed as a light passage opening in such a light quantity adjustment device (aperture device) is as close to circular as possible, and in order to form a diaphragm opening that is close to circular, a large number of diaphragm blades (light quantity adjustment blades), three or more, are often used.

[0005] Patent Document 2 discloses an iris diaphragm device that forms a polygonal aperture opening that is close to a circle by rotating a number of aperture blades using a drive ring that can rotate around a fixed aperture formed in a base member. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-322631 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-115831 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the configuration disclosed in Patent Document 1 that includes an iris diaphragm and an optical filter, the drive ring is arranged around the periphery of the diaphragm opening, and a retraction space for the many diaphragm blades is required over the entire circumference, which makes it easy for the device to become large over the entire circumference.

[0008] Furthermore, the diaphragm device disclosed in Patent Document 2 can reduce the size in the width direction perpendicular to the linear movement direction of the linearly moving diaphragm blades compared to an iris diaphragm device. However, like an iris diaphragm, it has a configuration in which a pair of linearly moving diaphragm blades and a pair of oscillating diaphragm blades are driven by rotating an annular plate equivalent to a drive ring arranged around the diaphragm opening, and so there is a limit to how compact the device can be.

[0009] The present invention provides a light amount adjusting device that can be made smaller in size, and an optical apparatus equipped with the same. [Means for solving the problem]

[0010] In order to solve the above problem, the light amount adjusting device of the present invention is a light amount adjusting device having: a base member that forms a fixed opening through which light passes; a plurality of diaphragm blades that move in a direction perpendicular to the optical axis that is perpendicular to the direction through which light passes, and advance and retreat relative to the fixed opening, forming an diaphragm opening that is smaller than the fixed opening; a first drive unit that is located at a position away from the fixed opening and moves the plurality of diaphragm blades forward and backward; a light amount adjusting member that rotates on a plane parallel to the direction in which the diaphragm blades advance and retreat relative to the fixed opening, and a second drive unit that includes a rotatable magnet and operates the light amount adjusting member; and the second drive unit is located such that at least two of the plurality of diaphragm blades move in a direction connecting the first drive unit and the fixed opening, pass through the fixed opening, and are in a direction perpendicular to the direction of movement of the diaphragm blades. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a small light amount adjusting device that makes effective use of space and is equipped with a light amount adjusting blade and an aperture for reducing or blocking light. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a front view of a light amount adjusting device according to a first embodiment; [Figure 2] 1 is a rear view of a light amount adjusting device according to a first embodiment; [Figure 3] FIG. 1 is a perspective view of the front side of a light amount adjustment device according to a first embodiment; [Figure 4] FIG. 1 is an exploded perspective view of a light amount adjusting device according to a first embodiment. [Figure 5] Operation diagram of the aperture of the light amount adjusting device according to the first embodiment [Figure 6] Operation diagram of the ND filter of the light amount adjusting device according to the first embodiment [Figure 7] FIG. 10 is a front view of a light amount adjusting device according to a second embodiment. [Figure 8] 10 is a rear view of the light amount adjusting device according to the second embodiment. [Figure 9] FIG. 10 is a perspective view of the front side of the light amount adjustment device according to the second embodiment. [Figure 10]FIG. 10 is an exploded perspective view of a light amount adjusting device according to a second embodiment. [Figure 11] 10 is a diagram illustrating the operation of the shutter of the light amount adjusting device according to the second embodiment. [Figure 12] FIG. 10 is a front view of a light amount adjusting device according to a third embodiment. [Figure 13] 10 is a rear view of the light amount adjusting device according to the third embodiment. [Figure 14] FIG. 10 is a perspective view of the front side of the light amount adjustment device according to the third embodiment. [Figure 15] FIG. 10 is a perspective view of the rear side of the light amount adjusting device according to the third embodiment. [Figure 16] FIG. 10 is an exploded perspective view of a light amount adjusting device according to a third embodiment. [Figure 17] FIG. 10 is an exploded perspective view of the diaphragm of the light amount adjusting device according to the third embodiment. [Figure 18] Operation diagram of the aperture of the light amount adjusting device according to the third embodiment [Figure 19] 10 is a diagram illustrating the operation of the shutter of the light amount adjusting device according to the third embodiment. [Figure 20] Operation diagram of the ND filter of the light amount adjusting device according to the third embodiment [Figure 21] Optical apparatus equipped with a light amount adjusting device according to the fourth embodiment DETAILED DESCRIPTION OF THE INVENTION

[0013] Example 1 A first embodiment of the present invention will be described in detail with reference to FIGS.

[0014] Fig. 1 is a plan view of a light amount adjusting device according to an embodiment of the present invention. Fig. 2 is a rear view of the light amount adjusting device, Fig. 3 is a perspective view of the light amount adjusting device, and Fig. 4 is an exploded perspective view of the light amount adjusting device. Fig. 5 shows the operation of the aperture of the light amount adjusting device, and Fig. 6 shows the operation of the neutral density filter.

[0015] In these figures, the diaphragm base plate 101 is a member that supports the diaphragm structure, and has a diaphragm fixed opening 101b that allows light to pass through formed therein. A diaphragm driver 102, which will be described later, is attached to the outer surface of the diaphragm base plate 101 (one surface in the optical axis direction) at a position away from the diaphragm fixed opening 101b.

[0016] The aperture driver 102 is attached to the aperture base plate 101 and serves as the aperture driver. An electromagnetic actuator such as a stepping motor or a galvanometer can be used as the aperture driver 102. The aperture driver has an output shaft 102b, and by electrically controlling the aperture driver 102, it can be rotated at any angle.

[0017] The drive arm 103 has blade drive pins 103i and 103j at the ends on either side of the output shaft 102b as transmission units for driving the diaphragm blade group 104 described below. The blade drive pin 103i engages with the diaphragm blade 105, and the blade drive pin 3j engages with the diaphragm blade 106. The diaphragm drive arm 103 is fixed to the output shaft 102b of the diaphragm drive unit by press-fitting or adhesive, and the diaphragm drive lever 103 rotates around the output shaft 102b as the center of rotation in response to the rotation of the output shaft 102b.

[0018] The diaphragm blade group 104 is made up of a plurality of diaphragm blades, and the light amount adjustment device of this embodiment is made up of two diaphragm blades 105 and 106. The diaphragm blades 105 and 106 are thin plate-like members with light-blocking properties, and have elongated drive holes 105i and 106j through which blade drive pins 103i and 103j pass. The diaphragm blades 105 and 106 are made by pressing a thin resin sheet coated with light-blocking paint, by pressing a thin metal plate that has been lubricated, or by molding into a thin plate shape.

[0019] Next, the structure of the light amount adjustment member will be described. The light amount adjustment device 100 in this embodiment is equipped with a neutral density filter as the light amount adjustment member. The neutral density filter is also called an ND (Neutral Density) filter, and will be referred to as an ND filter hereinafter.

[0020] The base member 107 is a member that serves as the base of the light amount adjustment device 100, and is formed with a fixed opening 107b that allows light to pass through. The base member 107 is assembled parallel to the diaphragm base plate 101 so that the diaphragm fixed opening 101b and the fixed opening 107b are coaxial, and a diaphragm blade chamber that houses the diaphragm blade group 104 is formed between the base member 107 and the diaphragm base plate 101. An ND drive unit 108 is attached to the surface of the base member 107 facing the diaphragm blade chamber. Reference numeral 109 denotes a magnet, the outer circumferential surface of which is magnetized with two poles (N pole and S pole).

[0021] The ND drive lever 110 is configured as one unit with the magnet 109. Methods for integrating them include bonding with an adhesive, or insert injection molding if using resin. The magnet 109 and ND drive lever 110 configured as one unit are supported by a drive lever rotation shaft (not shown) that is provided on the base member 107, and are capable of rotational movement. A stator yoke 111 made of a soft magnetic material is placed on the outer curved surface of the magnet 109. The electromagnetic coil unit 112 is configured by winding a coil made of a conducting wire around a bobbin. This electromagnetic coil unit 112 is attached to the base member 107 with the stator yoke 111 inserted. An actuator cover 113 is attached to the base member 107, and holds the stator yoke 111 and the ND drive lever 110.

[0022] As shown in the figure, the magnet 109, ND drive lever 110, stator yoke 111, electromagnetic coil unit 112, and actuator cover 113 are assembled to form an electromagnetic actuator, which becomes the ND drive unit 108 and drives the ND blades 114 described below.

[0023] The ND blades 114 are made up of an ND filter 114a that attenuates the amount of light passing through and an ND holding blade 114b that holds the ND filter. The ND blades 114 are equipped with a blade rotation hole 114c that fits with the blade rotation shaft 107d of the base member, and a cam hole 114d that fits with the ND drive lever 110. The ND blades 114 are rotated around the blade rotation hole 114c by the ND drive unit 108, and can be moved toward and away from the fixed opening 107b of the base member, allowing the ND blades 114 to be switched between a state in which the light passing through the fixed opening 107b is attenuated and a state in which it is not attenuated.

[0024] In this embodiment, the light amount adjusting member is an ND filter, but by changing the characteristics of the filter, the same configuration can be adopted for various optical filters such as an IR cut filter or a bandpass filter.

[0025] The cover plate 115 is attached parallel to the base member 107, and an ND blade chamber in which the ND blade 114 is housed is formed between the cover plate 115 and the base member 107.

[0026] Next, the operation of the diaphragm will be described with reference to the drawings. Figure 5(a) shows a state in which the diaphragm blades 105 and 106 are retracted from the diaphragm fixed opening 101b of the diaphragm base plate, which serves as a light passage opening.

[0027] When the aperture drive unit 102 is rotated clockwise from the state shown in Figure 5(a), the aperture drive lever 103 press-fitted onto the output shaft 102b of the aperture drive unit rotates, causing the blade drive pins 103i and 103j to rotate clockwise. The aperture blade 105 receives force from the cam hole 105i fitted into the blade drive pin 103i, and moves linearly upward in Figure 5 along the guide hole 105b. The aperture blade 106 receives force from the cam hole 106j fitted into the blade drive pin 103j, and moves linearly downward in Figure 5 along the guide hole 106b. The aperture formed by the aperture blades 105 and 106 through which light passes becomes smaller, and the amount of light passing through the light amount adjustment device 100 can be reduced.

[0028] 5(c) shows a state in which the diaphragm driving unit 102 has been rotated further from (b), so that the amount of light passing through the light amount adjustment device 100 can be further reduced.

[0029] 5(d) shows a state in which the diaphragm driver 102 has been rotated further from (c). The diaphragm fixed opening 101b, which serves as a light passage port, is closed by the diaphragm blades 105 and 106, blocking light. By rotating the rotation phase of the diaphragm driver 102 to any position, it is possible to change the area of ​​the diaphragm opening in FIGS. 5(a) to 5(d) to any desired area, and the amount of light passing through the light amount adjustment device 100 can be adjusted.

[0030] As described above, the aperture blades 105 and 106 move in the vertical direction in Figure 5, that is, in the direction connecting the aperture drive unit 102 and the aperture fixed opening 101b and fixed opening 107b, thereby changing the amount of light passing through the light amount adjustment device 100.

[0031] In addition, it is possible to use the device as a shutter device by rotating the aperture drive unit 102 at high speed from any of the states shown in Figures 5(a) to (c) to the state shown in Figure 5(d) and blocking light from the aperture fixed opening 101b.

[0032] 1 to 6, the line connecting fixed aperture 107b, which is a light passage opening, and aperture driver 102 is arranged so that it is perpendicular to the line connecting fixed aperture 107b and ND driver 108. The line connecting fixed aperture 107b and aperture driver 102 coincides with the direction of movement of aperture blades 105 and 106, and the direction of movement of aperture blades 105 and 106 is arranged so that it is perpendicular to the line connecting fixed aperture 107b and ND driver 108. By arranging the aperture structure and the ND driver in this way, space can be used effectively, and the external dimensions of light amount adjustment device 100 can be made smaller.

[0033] Example 2 The configuration of a light amount adjusting device 200 according to a second embodiment of the present invention will be described in detail with reference to Figures 7 to 11. In the configuration of this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals.

[0034] Fig. 7 is a plan view of the light amount adjusting device according to Example 2. Fig. 8 is a rear view of the light amount adjusting device, Fig. 9 is a perspective view of the light amount adjusting device, and Fig. 10 is an exploded perspective view of the light amount adjusting device. Fig. 11 shows the operation of the shutter.

[0035] In these figures, the aperture base plate 101, aperture drive unit 102, aperture drive lever 103, and aperture blade group 103 are substantially the same in configuration as those of the light amount adjustment device 100 of the first embodiment.

[0036] The light amount adjusting device 200 in this embodiment is equipped with shutter blades as light amount adjusting members.

[0037] The shutter drive unit 201 is a moving magnet type drive unit made up of an electromagnetic coil, similar to the ND drive unit 108 in embodiment 1. The shutter drive lever 202 rotates integrally with the magnet 109.

[0038] Shutter blades 203 and 204 are made of thin, light-blocking plate-like members, and have shutter blade rotation shaft holes 203a and 204a and cam holes 203b and 204b. Shutter drive lever 202 rotates via shutter drive unit 201, and shutter blades 203 and 204 rotate about shutter blade rotation shaft holes 203a and 204a, and can advance into and retract from fixed opening 107b in the base member, covering and opening fixed opening 107b.

[0039] As with the ND driver 108 of the first embodiment, the line connecting the fixed aperture 107b, which is a light passage opening, and the diaphragm driver 102 is arranged so that the line connecting the fixed aperture 107b and the shutter driver 201 is perpendicular to the line connecting the fixed aperture 107b and the shutter driver 201.

[0040] The straight line connecting the fixed aperture 107b and the aperture drive unit 102 coincides with the direction of movement of the aperture blades 105 and 106, and the direction of movement of the aperture blades 105 and 106 is arranged so as to be perpendicular to the straight line connecting the fixed aperture 107b and the shutter drive unit 201.

[0041] By arranging the diaphragm structure and the shutter drive unit in this way, it is possible to effectively utilize the space and reduce the external size of the light amount adjustment device 200.

[0042] Example 3 The configuration of a light amount adjusting device 300 according to a third embodiment of the present invention will be described in detail with reference to Figures 12 to 20. In the configuration of this embodiment, the same components as those in the first or second embodiment are denoted by the same reference numerals.

[0043] Fig. 12 is a plan view of a light amount adjusting device according to Example 3. Fig. 13 is a rear view of the light amount adjusting device, Figs. 14 and 15 are perspective views of the light amount adjusting device, Fig. 16 is an exploded perspective view of the light amount adjusting device, and Fig. 17 is an exploded perspective view showing only the aperture structure of the light amount adjusting device. Fig. 18 shows the operation of the aperture of the light amount adjusting device, Fig. 19 shows the operation of the shutter, and Fig. 20 shows the operation of the ND filter.

[0044] In these figures, the aperture base plate 301 and the aperture drive unit 302 are the same as those in the first and second embodiments.

[0045] The drive arm 303 has blade drive pins 303i and 303j at the ends on both sides of the output shaft 302b as transmission units for driving the diaphragm blade group 304 (described below). The blade drive pin 303i is engaged with a three-blade group consisting of a rotary diaphragm blade 306, a linear diaphragm blade 307, and a rotary diaphragm blade 308. The blade drive pin 303j is engaged with a three-blade group consisting of rotary diaphragm blades 305 and 309, and a linear diaphragm blade 310. The diaphragm drive arm 303 is fixed to the output shaft 302b of the diaphragm drive unit by press-fitting or adhesive, and the diaphragm drive lever 303 rotates around the output shaft 302b as the center of rotation in response to the rotation of the output shaft 302b.

[0046] The aperture blade group 304 is made up of a plurality of aperture blades, and in this embodiment, the aperture blade group 304 is made up of a total of six aperture blades: two linear aperture blades 307 and 310 and four rotary aperture blades 305, 306, 308, and 309, and each aperture blade is a thin plate-like member with light-blocking properties.

[0047] The linear diaphragm blade 307 is slidably engaged with a blade drive pin 303i of the drive arm 303 at a drive elongated hole 307i. Furthermore, shafts 301c and 301d formed on the diaphragm base plate 301 are slidably engaged with guide elongated holes 307c and 307d formed in the linear diaphragm blade 307 so as to extend in a direction perpendicular to the optical axis. The elongated hole 307f has a relief shape that avoids the shaft 301f formed on the diaphragm base plate 301.

[0048] When the drive arm 303 rotates within the above-mentioned specified angle range, the linear aperture blade 307 receives a drive force from the blade drive pin 303i at the drive elongated hole portion 307i, and the guide elongated holes 306c and 306d move in a direction perpendicular to the optical axis and in a direction connecting the aperture drive unit 302 and the aperture fixed opening 301b and fixed opening 311b while being guided by the shaft portions 301c and 301d of the aperture base plate, respectively.

[0049] The linear diaphragm blade 310 is slidably engaged with a blade drive pin 303j of the drive arm 303 at a drive elongated hole 310j. Furthermore, the shaft 301f of the diaphragm base plate 301 and the shaft 301e similarly formed on the diaphragm base plate 301 are slidably engaged with guide elongated holes 310f, 310e formed in the linear diaphragm blade 310 so as to extend in a direction perpendicular to the optical axis, respectively. The elongated hole 310c has a relief shape that avoids the shaft 301c of the diaphragm base plate.

[0050] When the drive arm 303 rotates within the above-mentioned specified angle range, the linear aperture blade 310 receives a drive force from the blade drive pin 303j at the drive elongated hole portion 310j, and the guide elongated holes 310e and 310f move in a direction perpendicular to the optical axis and in a direction connecting the aperture drive unit 302 and the aperture fixed opening 301b and fixed opening 311b while being guided by the shaft portions 301e and 301f of the aperture base plate, respectively.

[0051] The rotary diaphragm blade 305 is slidably engaged with a blade drive pin 303j of the drive arm 303 at a drive cam groove 305j. Furthermore, a shaft 301d formed on the diaphragm base plate 301 and serving as a rotation center shaft is rotatably engaged with a rotation center hole 305d formed in the rotary diaphragm blade 305. That is, the shaft 301d not only has the function of slidably engaging with the guide elongated hole 307d of the linear diaphragm blade 307 to guide the linear diaphragm blade 307 in its movement direction as described above, but also has the function of engaging with the rotation center hole 305d of the rotary diaphragm blade 305 to form the rotation center of the rotary diaphragm blade 305.

[0052] Furthermore, the rotary diaphragm blade 306 is slidably engaged with a blade drive pin 303i of the drive arm 303 at a drive cam groove 306i. Also, a shaft 301e formed in the diaphragm base plate 301 and serving as a rotation center shaft is rotatably engaged with a rotation center hole 306e formed in the rotary diaphragm blade 306. That is, the shaft 301e not only has the function of slidably engaging with the guide elongated hole 310e of the linear diaphragm blade 310 to guide the linear diaphragm blade 310 in its movement direction as described above, but also has the function of engaging with the rotation center hole 306e of the rotary diaphragm blade 306 to form the rotation center of the rotary diaphragm blade 306.

[0053] When the drive arm 303 rotates within the above-mentioned predetermined angle range, the drive cam grooves 305j and 306i receive driving force from the blade drive pins 303j and 303i, causing the rotary diaphragm blades 305 and 306 to rotate (pivot) in a plane perpendicular to the optical axis around the shafts 301d and 301e engaged with the rotation center holes 305d and 306e. The speed of this rotation can be adjusted by changing the shape of the drive cam grooves 305j and 306i.

[0054] Furthermore, rotary diaphragm blade 308 and rotary diaphragm blade 309 are slidably engaged with blade drive pins 303i and 303j of drive arm 303 at drive cam grooves 308i and 309j, respectively. Rotation center holes 308d and 309e formed in rotary diaphragm blades 308 and 309 are rotatably engaged with shafts 301d and 301e, respectively, which serve as rotation centers (rotation center shafts) formed in diaphragm base plate 301. That is, as described above, shafts 301d and 301e not only have the function of slidably engaging with guide elongated holes 307d and 310e of linear diaphragm blades 307 and 310 to guide linear diaphragm blades 307 and 310 in their movement directions, but also have the function of engaging with rotation center holes 308d and 309e of rotary diaphragm blades 308 and 309 to form the rotation centers of rotary diaphragm blades 308 and 309.

[0055] When drive arm 303 rotates within the above-mentioned predetermined angle range, drive cam grooves 308i and 309j receive driving forces from blade drive pins 303i and 303j, respectively, and rotary diaphragm blades 308 and 309 rotate (pivot) in a plane perpendicular to the optical axis around shafts 301d and 301e engaged with rotation center holes 308d and 309e. The speed of this rotation can be adjusted by changing the shape of drive cam grooves 308i and 309j.

[0056] The rotational positions of the rotary diaphragm blades 305, 306, 308, and 309 relative to the rotational position of the drive arm 303, and therefore the shape of the diaphragm aperture, can be appropriately set by adjusting the shapes of the drive cam grooves 305j, 306i, 308i, and 309j formed on the respective rotary diaphragm blades 305, 306, 308, and 309. This allows the aperture to be formed by the aperture-forming edges 305b-310b of the diaphragm blades 305-310 in each aperture state, from the fully open aperture shown in Fig. 18(a), through the intermediate aperture shown in Fig. 18(b), to the small aperture shown in Fig. 18(c), and the closed state shown in Fig. 18(d). The diaphragm apertures, except for the fully open aperture, have a shape resembling a regular hexagon close to a circle.

[0057] The base member 311 is assembled in parallel to the diaphragm base plate 301, and a diaphragm blade chamber in which the diaphragm blade group 304 is housed is formed between the base member 311 and the diaphragm base plate 301. A shutter drive unit 312 and an ND drive unit 317 are attached to the base member 311 on the diaphragm blade chamber side.

[0058] The shutter drive unit 312 is similar to the ND drive unit 108 in the first embodiment and the shutter drive unit 201 in the second embodiment, and is a moving magnet type drive unit consisting of a magnet, a drive lever, a stator yoke, and an actuator cover, and operates shutter blades 314 and 315 (described below) via a shutter drive lever 313.

[0059] As shown in the figure, the straight line connecting the fixed aperture 311b, which serves as a light passage opening for the device, and the diaphragm driving unit 302 and the straight line connecting the light passage opening and the ND driving unit 108 are arranged so as to intersect at right angles.

[0060] The straight line connecting the fixed aperture 311b, which serves as the light passage opening of the device, and the aperture drive unit 302 coincides with the operating direction of the linear aperture blades 307 and 310, and the operating direction of the linear aperture blades 307 and 310 is arranged so as to be perpendicular to the straight line connecting the light passage opening and the shutter drive unit 312.

[0061] The shutter blades 314 and 315 have the same configuration as the shutter blades 203 and 204 of the second embodiment, and the shutter blades 314 and 315 rotate around the shutter blade rotation shaft holes 314a and 315a to cover and open the fixed opening 311b.

[0062] The ND drive unit 317 is similar to the ND drive unit 108 in the first embodiment and the shutter drive unit 201 in the second embodiment, and is a moving magnet type drive unit consisting of a magnet, a drive lever, a stator yoke, and an actuator cover, and operates the ND blades described below via the ND drive lever 318.

[0063] As shown in the figure, the line connecting fixed opening 311b, which serves as a light passage opening for the device, and aperture driver 302 is perpendicular to the line connecting the light passage opening and ND driver 108. The line connecting the light passage opening and aperture driver 302 coincides with the direction of movement of linear aperture blade 307 and linear aperture blade 310, and the direction of movement of linear aperture blade 307 and linear aperture blade 310 is perpendicular to the line connecting the light passage opening and shutter driver 312. Furthermore, shutter driver 312 and ND driver 317 are positioned opposite each other across fixed opening 311b in the base member, which serves as a light passage opening. Arranging the aperture structure, shutter driver 312, and ND driver 317 in this way makes it possible to effectively utilize space and reduce the external size of light intensity adjustment device 300.

[0064] The ND blade 319 has the same configuration as the ND blade 114 of the first embodiment, and is made up of an ND filter 319a that reduces the amount of light passing through and an ND holding blade 319b that holds the ND filter. The ND blade 319 has a blade rotation hole 319c that fits with the ND blade rotation shaft of the base member, and a cam hole 319d that fits with the ND drive lever 318. The ND blade 319 is rotated around the blade rotation hole 319c by the ND drive unit 317, and moves toward and away from the fixed opening 311b of the base member, thereby reducing the amount of light that passes through the fixed opening 311b of the light amount adjustment device.

[0065] The cover plate 318 is attached parallel to the base member 311 and is a component that determines the outer shape of the light amount adjustment device 300. The partition member 316 is attached parallel to the base member 311 and the cover plate 318 with a predetermined space between them. In this embodiment, a shutter blade chamber in which shutter blades 314 and 315 are housed is formed between the base member 311 and the partition member 316, and an ND blade chamber in which ND blade 319 is housed is formed between the cover plate 318 on the opposite side and the partition member 316.

[0066] Example 4 21 shows an interchangeable lens 421 for an interchangeable lens camera as an imaging device equipped with the light amount adjustment device 300 described in Example 3, and the internal configuration of a camera body to which the interchangeable lens is attached. The light amount adjustment device 300 may be the light amount adjustment device 100 described in the first embodiment or the light amount adjustment device 200 described in the second embodiment.

[0067] The lens barrel of the interchangeable lens 421 houses a photographic optical system including a variable magnification lens 432, the light amount adjustment device 300 described in the third embodiment, which includes an aperture, a shutter, and an ND filter, and a focus lens 429.

[0068] An image sensor 425, which is configured with a photoelectric conversion element such as a CCD sensor or a CMOS sensor, is disposed inside the camera body and photoelectrically converts the subject image formed by the interchangeable lens 421 to output an electrical signal. The brightness of the subject image formed on the image sensor 425 (i.e., the amount of light reaching the image sensor 425) can be appropriately set by changing the aperture of the light amount adjustment device 300, controlling the timing of advancing and retracting the shutter blades 314 and 315, and advancing and retracting the ND filter 319a.

[0069] The electrical signal output from the image sensor 425 is converted into a digital signal in the image processing circuit 426 and subjected to various image processing, thereby generating an image signal.

[0070] A user can change the magnification (zoom) by moving a variable magnification lens 432 by rotating a zoom ring 431. The controller 422 detects the contrast of an image signal, controls a focus motor 428 in accordance with the contrast, and moves a focus lens 429 to perform autofocus. Alternatively, the controller 422 may control the focus motor 428 and move a focus lens 429 to perform autofocus based on a detection signal from a focus detection means using a phase difference detection method (not shown).

[0071] Furthermore, the controller 422 controls the aperture driver 302, shutter driver 312, and ND driver 317 of the light amount adjustment device 300 based on the photometric value of a photometric means (not shown) or an image signal, and adjusts the amount of light. This makes it possible to make blur and ghosting during shooting appear more natural, and to record high-quality images.

[0072] The present invention is not limited to the above-mentioned interchangeable lens camera, but can also be widely applied to optical devices such as integrated lens digital cameras and video cameras.

[0073] The above-described embodiments are merely representative examples, and when implementing the present invention, Various modifications and variations are possible. [Explanation of symbols]

[0074] 100 Light intensity adjustment device 101 Aperture base plate 102 Aperture drive unit 104 Aperture blades 105 aperture blades 106 aperture blades 107 Base material 107b Fixed aperture 107h ND rotation axis 108 ND drive unit 109 Magnet 114 ND blade 114a ND filter 425 image sensor

Claims

1. a base member forming a fixed aperture through which light passes; a plurality of aperture blades that move in a direction perpendicular to the optical axis, which is perpendicular to the direction in which light passes, and move toward and away from the fixed aperture, and form an aperture opening that is smaller than the fixed aperture; a first drive unit disposed at a position away from the fixed opening and configured to move the plurality of diaphragm blades forward and backward; a light amount adjusting member that rotates on a plane parallel to the direction in which the diaphragm blades advance and retreat and advances and retreats relative to the fixed opening; a second drive unit including a rotatable magnet and operating the light amount adjustment member, A light amount adjusting device characterized in that at least two of the plurality of diaphragm blades move in a direction connecting the first drive unit and the fixed opening, and the second drive unit is arranged in a direction passing through the fixed opening and perpendicular to the direction of movement of the diaphragm blades.

2. 2. The light amount adjusting device according to claim 1, wherein said light amount adjusting member is a light-reducing filter.

3. The light amount adjusting member is a shutter blade, and the shutter blade moves forward and backward into the fixed opening.

2. The light amount adjusting device according to claim 1,

4. a third drive unit including a rotatable magnet; and a second light amount adjustment member that rotates on a plane parallel to the direction in which the diaphragm blades advance and retreat and advances and retreats relative to the fixed opening.

2. The light amount adjusting device according to claim 1, further comprising a third driving unit disposed in a direction perpendicular to the direction of movement of said diaphragm blades.

5. 5. The light amount adjusting device according to claim 4, wherein the second driving unit and the third driving unit are disposed at positions facing each other with the fixed opening interposed therebetween.

6. 6. An optical device comprising: the light amount adjusting device according to claim 1; and an imaging element that captures an image of light that has passed through the light amount adjusting device.

Images