Blade driving device and imaging apparatus including the same

Abstract

To selectively use a blade for reducing light quantity and a blade for shielding light within a single device according to application.SOLUTION: A blade driving device 1 comprises: a frame body 10 provided with an aperture S; light quantity-attenuating blades 21-24 configured to partially transmit light; arms 41, 42 configured to be rotatable about a rotation shaft 11 and connected to the light quantity-attenuating blades 21-24; a first drive unit that rotates the arms 41, 42 about the rotation shaft 11 so that the light quantity-attenuating blades 21-24 move between a first retracted position where they are retracted from the aperture S and a first operating position where they are located within the aperture S; light-shielding blades 31-34 configured to block light; arms 51, 52 configured to be rotatable about a rotation shaft 12 and connected to the light-shielding blades 31-34; and a second drive unit that rotates the arms 51, 52 about the rotation shaft 12 so that the light-shielding blades 31-34 move between a second retracted position where they are retracted from the aperture S and a second operating position where they are located within the aperture S.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a blade drive device and an imaging device equipped with the same. [Background technology]

[0002] Many cameras are provided with a blade drive device that drives blades to open and close an exposure aperture. Known examples of such blades include shutter blades that open and close the aperture and ND (Neutral Density) filter blades that reduce the amount of light that passes through the aperture (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-106970 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional blade drive devices drive only one type of blade for one purpose (for example, reducing the amount of light). Therefore, when driving multiple types of blades for multiple purposes, it is necessary to provide a blade drive device for each purpose, which requires multiple blade drive devices.

[0005] The present invention has been made in view of the problems of the conventional technology, and aims to provide a blade drive device that can use multiple types of blades within a single device depending on the application. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a blade drive device that can selectively use a plurality of types of blades depending on the application. The blade drive device includes a frame body having an opening, at least one light-attenuating blade that partially transmits light, a first arm unit configured to be rotatable about a first rotation axis and connected to the at least one light-attenuating blade, a first drive unit that rotates the first arm unit about the first rotation axis so that the at least one light-attenuating blade moves between a first retracted position where it retracts from the opening and a first operating position where it is located within the opening, at least one light-shielding blade that blocks light, a second arm unit configured to be rotatable about a second rotation axis and connected to the at least one light-shielding blade, and a second drive unit that rotates the second arm unit about the second rotation axis so that the at least one light-shielding blade moves between a second retracted position where it retracts from the opening and a second operating position where it is located within the opening.

[0007] According to another aspect of the present invention, there is provided an imaging device comprising the above-mentioned blade drive device and an imaging element arranged on a surface where light passing through the opening provided in the frame of the blade drive device forms an image. [Effects of the Invention]

[0008] According to the blade drive device of the present invention, two types of blades, namely, light attenuation blades and light blocking blades, can be selectively used within a single device depending on the application. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a front view showing the main part of a blade drive device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic rear view of the blade drive device shown in FIG. [Figure 3] FIG. 3 is a diagram schematically showing a cross section of the light-attenuation blade shown in FIG. 1 taken along line AA. [Figure 4] FIG. 4 is a front view of the blade drive device shown in FIG. 1 in a dimming state. [Figure 5]FIG. 5 is a front view of the blade drive device shown in FIG. 1 in a light-blocking state. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of a blade drive device and an imaging device according to the present invention will be described in detail with reference to FIGS. 1 to 5. In FIGS. 1 to 5, identical or corresponding components are denoted by the same reference numerals, and duplicate explanations will be omitted. Furthermore, in FIGS. 1 to 5, the scale and dimensions of each component may be exaggerated, and some components may be omitted. In the following description, unless otherwise specified, terms such as "first" and "second" are used merely to distinguish components from one another, and do not indicate a particular order or ranking.

[0011] FIG. 1 is a front view showing the main components of a blade drive device 1 according to one embodiment of the present invention, and FIG. 2 is a schematic rear view. As shown in FIGS. 1 and 2, the blade drive device 1 according to this embodiment includes a frame 10 having a rectangular opening S formed therein, a cover (not shown) attached to the +Z side of the frame 10, eight blades 21-24, 31-34 housed in a space formed between the frame 10 and the cover, arms 41 and 42 connected to the blades 21-24, and arms 51 and 52 connected to the blades 31-34. This blade drive device 1 is incorporated into an imaging device equipped with an imaging element (not shown) such as a CCD or CMOS sensor. In this embodiment, the +Z side is the subject side, and light from the subject passes through the opening S in the frame 10 and enters the imaging element located on the -Z side of the blade drive device 1. Depending on the configuration of the imaging device, the -Z side may be the subject side and the +Z side may be the imaging element side.

[0012] Each of the blades 21 to 24 is a thin plate-like member and is a light attenuation blade (ND filter blade) configured to partially transmit light. In the example shown in Fig. 1, the light attenuation blades 21 to 24 extend in the X direction as a whole, and these light attenuation blades 21 to 24 are stacked in order in the Z direction.

[0013] These light-attenuating blades 21 to 24 have the same configuration, and the configuration of light-attenuating blade 21 will be described here as a representative example. FIG. 3 is a diagram schematically illustrating a cross section of light-attenuating blade 21 shown in FIG. 1 taken along line AA. As shown in FIG. 3, light-attenuating blade 21 in this embodiment is composed of blade plate 21A having light-transmitting properties and light-attenuating film 21B attached to blade plate 21A. Such light-attenuating film 21B is formed by mixing a light-absorbing pigment into a resin such as cellulose acetate, polyethylene terephthalate (PET), or polyvinyl chloride. Such light-attenuating film 21B can be bonded to blade plate 21A by pressing while heating. That is, by forming light-attenuating blade 21 by bonding light-attenuating film 21B to blade plate 21A, a blade that has both light-attenuating function and rigidity can be obtained. Alternatively, if the rigidity of the light attenuation blades 21 to 24 can be ensured, the light attenuation blades 21 to 24 can be made up of only such a light attenuation film.

[0014] Each of the blades 31 to 34 is a thin plate-like member and a light-shielding blade configured to block light. Such light-shielding blades 31 to 34 are made of, for example, metal or resin. In the example shown in Fig. 1, each of the light-shielding blades 31 to 34 extends in the X direction as a whole, and these light-shielding blades 31 to 34 are stacked in order in the Z direction.

[0015] The arm 41 is configured to be rotatable around the rotation axis 11 (first rotation axis), and the arm 42 is configured to be rotatable around the rotation axis 17. As shown in FIG. 1 , the light attenuation blade 21 is connected to the arms 41 and 42 by pins 61 and 62, respectively, the light attenuation blade 22 is connected to the arms 41 and 42 by pins 63 and 64, respectively, the light attenuation blade 23 is connected to the arms 41 and 42 by pins 65 and 66, respectively, and the light attenuation blade 24 is connected to the arms 41 and 42 by pins 67 and 68, respectively. In this way, the arm 41 in this embodiment is configured to be rotatable around the rotation axis 11, and constitutes a first arm portion connected to the light attenuation blades 21 to 24. Furthermore, each of the light attenuation blades 21 to 24 and the two arms 41 and 42 constitute a link mechanism.

[0016] Arm 51 is configured to be rotatable around rotation axis 12 (second rotation axis), and arm 52 is configured to be rotatable around rotation axis 18. As shown in FIG. 1 , light-shielding blade 31 is connected to arms 51 and 52 by pins 71 and 72, respectively, light-shielding blade 32 is connected to arms 51 and 52 by pins 73 and 74, respectively, light-shielding blade 33 is connected to arms 51 and 52 by pins 75 and 76, respectively, and light-shielding blade 34 is connected to arms 51 and 52 by pins 77 and 78, respectively. In this way, arm 51 in this embodiment is configured to be rotatable around rotation axis 12, and constitutes a second arm portion connected to light-shielding blades 31 to 34. Furthermore, each of light-shielding blades 31 to 34 and the two arms 51 and 52 constitute a link mechanism.

[0017] 1 and 2, the frame body 10 is formed with an arc groove 13 along an arc centered on the rotation shaft 11, and the frame body 10 is formed with an arc groove 14 along an arc centered on the rotation shaft 12. As shown in FIG. 2, the blade drive device 1 has a first drive lever 80 attached to the rotation shaft 11 of the frame body 10, and a second drive lever 90 attached to the rotation shaft 12 of the frame body 10.

[0018] The first drive lever 80 has a shaft portion 81 into which the rotation shaft 11 of the frame body 10 is inserted, a drive pin 82 that passes through the arc groove 13 of the frame body 10 and protrudes in the +Z direction of the frame body 10, and a metal piece 83. The rotation shaft 11 of the frame body 10 is inserted into the shaft portion 81 of the first drive lever 80, so that the first drive lever 80 can rotate around the rotation shaft 11. When the first drive lever 80 rotates around the rotation shaft 11, the drive pin 82 of the first drive lever 80 moves within the arc groove 13. A shock absorbing damper 15 is provided at the end of the arc groove 13 of the frame body 10 on the -Y direction side.

[0019] A first drive spring (not shown) is attached to the first drive lever 80, biasing the first drive lever 80 counterclockwise around the rotation axis 11 in Fig. 2. This first drive spring is, for example, a torsion coil spring. A first electromagnet 85 capable of electromagnetically attracting a metal piece 83 is disposed close to the first drive lever 80, and the first electromagnet 85 electromagnetically attracts the metal piece 83 of the first drive lever 80, thereby holding the first drive lever 80 in the position shown in Fig. 2 against the force of the first drive spring.

[0020] The drive pin 82 of the first drive lever 80 passes through the arc groove 13 of the frame 10 and fits snugly into the lever connecting hole 43 provided in the arm 41, as shown in FIG. 1. Both the first drive lever 80 and the arm 41 rotate about the rotation shaft 11, so that when the drive pin 82 of the first drive lever 80 rotates about the rotation shaft 11, the arm 41 rotates about the rotation shaft 11. As a result, via the link mechanism formed by the arms 41, 42 and the light attenuation blades 21-24, the light attenuation blades 21-24 move mainly in the Y direction while changing the overlapping areas with each other. In this way, the first drive lever 80 in this embodiment constitutes a first drive unit that rotates the arm 41 about the rotation shaft 11 so that the light attenuation blades 21-24 move in the Y direction.

[0021] The second drive lever 90 has a shaft portion 91 into which the rotation shaft 12 of the frame body 10 is inserted, a drive pin 92 that passes through the arc groove 14 of the frame body 10 and protrudes in the +Z direction of the frame body 10, and a metal piece 93. By inserting the rotation shaft 12 of the frame body 10 into the shaft portion 91 of the second drive lever 90, the second drive lever 90 can rotate around the rotation shaft 12. When the second drive lever 90 rotates around the rotation shaft 12, the drive pin 92 of the second drive lever 90 moves within the arc groove 14. A shock absorbing damper 16 is provided at the end of the arc groove 14 of the frame body 10 on the +Y direction side.

[0022] A second drive spring (not shown) is attached to the second drive lever 90, biasing the second drive lever 90 clockwise around the rotation axis 12 in Fig. 2. This second drive spring is, for example, a torsion coil spring. A second electromagnet 95 capable of electromagnetically attracting a metal piece 93 is disposed close to the second drive lever 90, and the second electromagnet 95 electromagnetically attracts the metal piece 93 of the second drive lever 90, thereby holding the second drive lever 90 in the position shown in Fig. 2 against the force of the second drive spring.

[0023] The drive pin 92 of the second drive lever 90 passes through the arc groove 14 of the frame 10 and fits snugly into the lever connecting hole 53 provided in the arm 51, as shown in FIG. 1. Both the second drive lever 90 and the arm 51 rotate about the rotation shaft 12, so that when the drive pin 92 of the second drive lever 90 rotates about the rotation shaft 12, the arm 51 rotates about the rotation shaft 12. As a result, via the link mechanism formed by the arms 51, 52 and the light-shielding blades 31 to 34, the light-shielding blades 31 to 34 move mainly in the Y direction while changing the overlapping areas with each other. In this way, the second drive lever 90 in this embodiment constitutes a second drive unit that rotates the arm 51 about the rotation shaft 12 so that the light-shielding blades 31 to 34 move in the Y direction.

[0024] The imaging device in this embodiment is configured to perform exposure control on the imaging element using an electronic shutter, and captures an image in a state where blade drive device 1 opens opening S of frame body 10 (hereinafter referred to as the "open state") as shown in Figures 1 and 2. In this open state, light attenuation blades 21-24 are retracted in the +Y direction from opening S of frame body 10, and light-shielding blades 31-34 are retracted in the -Y direction from opening S of frame body 10. Hereinafter, the position of light attenuation blades 21-24 in this state will be referred to as the "first retracted position," and the position of light-shielding blades 31-34 will be referred to as the "second retracted position."

[0025] Furthermore, the blade drive device 1 in this embodiment is capable of transitioning from the open state to a state in which the amount of light incident on the imaging element can be attenuated (hereinafter referred to as the "dimming state"), and a state in which no light is allowed to be incident on the imaging element (hereinafter referred to as the "light blocking state").

[0026] When transitioning from the open state to the dimming state, the electromagnetic attraction of the metal piece 83 of the first drive lever 80 by the first electromagnet 85 is released. As a result, the first drive lever 80 rotates counterclockwise around the rotation axis 11 (FIG. 2) due to the biasing force of the first drive spring. Accordingly, the light attenuation blades 21-24 move primarily in the -Y direction from the first retracted position, via the arm 41 connected to the drive pin 82 of the first drive lever 80 and the link mechanism described above, while changing the area of ​​their mutual overlap. Finally, the light attenuation blades 21-24 move to a position where they block the opening S of the frame 10, as shown in FIG. 4, and enter the dimming state. The position of the light attenuation blades 21-24 at this time is referred to as the "first operating position."

[0027] In this way, by moving the light attenuation blades 21-24 from the first retracted position to the first operating position, the blade drive device 1 transitions from an open state to a dimming state, thereby attenuating the amount of light incident on the image sensor through the opening S of the frame 10. Normally, an ND filter needs to be attached in front of the lens, but according to this embodiment, the blade drive device 1 can achieve the same function as an ND filter without attaching an ND filter in front of the lens. Furthermore, because the blade drive device 1 can easily transition to the dimming state, it is possible to attenuate the amount of light only for captured images that require dimming. Furthermore, by moving the light attenuation blades 21-24 to the first operating position when not capturing images (for example, when changing lenses), the image sensor in the image sensor can be covered by the light attenuation blades 21-24, thereby preventing dust from adhering to the image sensor in the image sensor.

[0028] When transitioning from the dimmed state to the open state, a drive mechanism (not shown) rotates the first drive lever 80 clockwise around the rotation axis 11 in Figure 2 against the biasing force of the first drive spring, and the metal piece 83 of the first drive lever 80 is electromagnetically attracted by the first electromagnet 85, thereby realizing the open state shown in Figures 1 and 2.

[0029] When transitioning from the open state to the light-blocking state, the electromagnetic attraction of the metal piece 93 of the second drive lever 90 by the second electromagnet 95 is released. As a result, the second drive lever 90 rotates clockwise around the rotation axis 12 in FIG. 2 due to the biasing force of the second drive spring. Accordingly, the light-blocking blades 31 to 34 move primarily in the +Y direction from the second retracted position, via the arm 51 connected to the drive pin 92 of the second drive lever 90 and the link mechanism described above, while changing the area of ​​overlap. Finally, the light-blocking blades 31 to 34 move to a position where they block the opening S of the frame 10, as shown in FIG. 5, and enter the light-blocking state. The position of the light-blocking blades 31 to 34 at this time is referred to as the "second operating position."

[0030] In this way, by moving the light-shielding blades 31 to 34 from the second retracted position to the second operating position, the blade drive device 1 transitions from an open state to a light-shielding state, and light can be prevented from entering the imaging element through the opening S of the frame 10. This makes it possible to suppress noise and heat generated by unwanted light entering the imaging element. In other words, by applying the blade drive device 1 of this embodiment to an imaging device that controls exposure using an electronic shutter, it is possible to achieve effects different from the exposure function of a normal focal plane shutter. Furthermore, by moving the light-shielding blades 31 to 34 to the second operating position when not taking pictures (for example, during lens replacement), the imaging element in the imaging device can be covered by the light-shielding blades 31 to 34, thereby suppressing dust inside the imaging device from adhering to the imaging element.

[0031] When transitioning from the light-blocking state to the open state, a drive mechanism (not shown) rotates the second drive lever 90 counterclockwise around the rotation axis 12 in FIG. 2 against the biasing force of the second drive spring, and the metal piece 93 of the second drive lever 90 is electromagnetically attracted by the second electromagnet 95, thereby realizing the open state shown in FIGS. 1 and 2.

[0032] As described above, according to the blade drive device 1 of this embodiment, two types of blades, the light attenuation blades 21-24 and the light-shielding blades 31-34, can be used within a single device depending on the application. That is, by positioning the light attenuation blades 21-24 within the opening S of the frame 10, the amount of light entering the imaging element through the opening S can be attenuated, and by positioning the light-shielding blades 31-34 within the opening S, light can be prevented from entering the imaging element through the opening S of the frame 10, thereby preventing dust inside the imaging device from adhering to the imaging element. Furthermore, by retracting the light attenuation blades 21-24 and the light-shielding blades 31-34 to the outside of the opening S, the opening S is opened, allowing light to enter the imaging element.

[0033] In the above-described embodiment, an example was described in which four light attenuation blades 21 to 24 and four light-shielding blades 31 to 34 were used, but the number of light attenuation blades and light-shielding blades may be any number as long as they are one or more.

[0034] The type of light attenuated by the light-attenuating blades 21 to 24 and blocked by the light-shielding blades 31 to 34 is not limited to visible light. For example, the light-attenuating blades 21 to 24 may be configured to partially transmit light of a specific wavelength other than visible light (for example, infrared light), and the light-shielding blades 31 to 34 may be configured to block light of such a specific wavelength.

[0035] As described above, the blade drive device according to the present invention can employ the following configurations. [Configuration 1] a frame body having an opening; at least one light attenuation blade that partially transmits light; a first arm portion configured to be rotatable about a first rotation axis and connected to the at least one light attenuation blade; a first drive unit that rotates the first arm unit about the first rotation axis so that the at least one light-attenuation blade moves between a first retracted position where the at least one light-attenuation blade is retracted from the opening and a first operating position where the at least one light-attenuation blade is positioned within the opening; At least one light blocking blade that blocks light; a second arm portion configured to be rotatable about a second rotation axis and connected to the at least one light-shielding blade; a second drive unit that rotates the second arm unit about the second rotation axis so that the at least one light-shielding blade moves between a second retracted position where the at least one light-shielding blade is retracted from the opening and a second operating position where the at least one light-shielding blade is positioned within the opening; and A blade drive device comprising:

[0036] [Configuration 2] The first driving unit and the second driving unit are an open state in which the at least one light-attenuating blade is positioned at the first retracted position and the at least one light-shielding blade is positioned at the second retracted position to open the opening; a dimming state in which the at least one light-attenuating blade is positioned at the first operating position and the at least one light-shielding blade is positioned at the second retracted position; a light-blocking state in which the at least one light-attenuating blade is positioned at the first retracted position and the at least one light-blocking blade is positioned at the second operating position; configured to achieve The blade drive device according to configuration 1.

[0037] [Configuration 3] The at least one light attenuation blade is A slat board having a property of transmitting light; a light attenuation film attached to the blade; 3. The blade drive device according to configuration 1 or 2, comprising:

[0038] The imaging device according to the present invention may also have the following configuration. [Configuration 4] A blade drive device according to any one of configurations 1 to 3; an imaging element disposed on a surface where light transmitted through the opening provided in the frame of the blade drive device forms an image; An imaging device comprising:

[0039] [Configuration 5] 5. The imaging device according to configuration 4, wherein exposure control is performed on the imaging element using an electronic shutter.

[0040] Although the preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the above-described embodiments and may be embodied in various different forms within the scope of the technical concept thereof. [Explanation of symbols]

[0041] 1. Blade drive device 10 Frame 11 Rotation axis (first rotation axis) 12 Rotation axis (second rotation axis) 21~24 Light attenuation blade 21A Slats 21B Light Attenuation Film 31~34 Shading blades 41, 42 Arm (first arm part) 51, 52 Arm (second arm section) 80 First drive lever (first drive unit) 82 Drive pin 90 Second drive lever (second drive unit) S opening

Claims

1. a frame body having an opening; at least one light attenuation blade that partially transmits light; a first arm portion configured to be rotatable about a first rotation axis and connected to the at least one light attenuation blade; a first drive unit that rotates the first arm unit about the first rotation axis so that the at least one light-attenuation blade moves between a first retracted position where the at least one light-attenuation blade is retracted from the opening and a first operating position where the at least one light-attenuation blade is positioned within the opening; At least one light blocking blade that blocks light; a second arm portion configured to be rotatable about a second rotation axis and connected to the at least one light-shielding blade; a second drive unit that rotates the second arm unit about the second rotation axis so that the at least one light-shielding blade moves between a second retracted position where the at least one light-shielding blade is retracted from the opening and a second operating position where the at least one light-shielding blade is positioned within the opening; and A blade drive device comprising:

2. The first drive unit and the second drive unit an open state in which the at least one light-attenuating blade is positioned at the first retracted position and the at least one light-shielding blade is positioned at the second retracted position to open the opening; a dimming state in which the at least one light-attenuating blade is positioned at the first operating position and the at least one light-shielding blade is positioned at the second retracted position; a light-blocking state in which the at least one light-attenuating blade is positioned at the first retracted position and the at least one light-blocking blade is positioned at the second operating position; configured to achieve The blade drive device according to claim 1 .

3. The at least one light attenuation blade is A slat board having a property of transmitting light; a light attenuation film attached to the blade; The blade drive device of claim 1 , comprising:

4. The blade drive device according to any one of claims 1 to 3; an imaging element disposed on a surface where light transmitted through the opening provided in the frame of the blade drive device forms an image; An imaging device comprising:

5. The imaging device according to claim 4 , wherein exposure control is performed on the imaging element using an electronic shutter.

Images