JP7645656B2 - Blade drive device and imaging device equipped with same - Google Patents

Description

The present invention relates to a blade drive device and an imaging device equipped with the same, and in particular to a blade drive device for driving the shutter blades of a digital camera or the like.

In digital cameras and the like, the exposure aperture is opened and closed by moving the shutter blades at high speed to expose the image sensor. In the blade drive device that drives such shutter blades, wear powder and dust can be generated inside the device due to friction between the arm attached to the blade or the blade and the base plate. If such wear powder and dust adheres to the camera's image sensor, the quality of the image captured by the image sensor decreases, so various mechanisms have been devised to prevent the generated wear powder and dust from adhering to the image sensor (see, for example, Patent Document 1).

In recent years, as the number of pixels in the image sensors of digital cameras increases, the impact of wear particles and dust on image quality has become greater. Furthermore, the faster the shutter speed, the greater the degree of wear between components, making it easier for wear particles and dust to be generated. For this reason, there is a demand for technology that can effectively prevent the spread of wear particles and dust generated within the device.

JP 2003-280066 A

The present invention was made in consideration of the problems with the conventional technology, and aims to provide a blade drive device that can prevent wear powder and dust generated at the connection between the blade and the arm from diffusing outside the arm.

According to one aspect of the present invention, there is provided a blade drive device capable of suppressing the diffusion of wear powder and dust generated at a joint between a blade and an arm to the outside of the arm. This blade drive device includes a base plate having an opening formed therein for directing light from a subject to an image sensor, at least one blade movable on a moving plane to open and close the opening, and at least one arm rotatably connected to the at least one blade via a connecting part . The at least one arm has a plate part extending along the moving plane and to which the connecting part is attached , and a shielding wall extending from an edge of the plate part perpendicular to the plate part so as to surround the connecting part .

FIG. 1 is a front view showing a blade drive device according to an embodiment of the present invention. FIG. 2 is a front view showing a schematic state of the blade drive device shown in FIG. 1 with a cover plate removed. FIG. 3 is a perspective view showing a leading blade arm of the blade drive device shown in FIG. 2. FIG. FIG. 4A is a vertical cross-sectional view of the leading blade arm shown in FIG. FIG. 4B is a vertical cross-sectional view of the leading blade arm shown in FIG.

Hereinafter, an embodiment of a blade drive device according to the present invention will be described in detail with reference to Figs. 1 to 4B. In Figs. 1 to 4B, identical or corresponding components are denoted with the same reference numerals, and duplicated descriptions will be omitted. In addition, in Figs. 1 to 4B, 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 only to distinguish components from each other, and do not indicate a specific order or sequence.

Figure 1 is a front view showing a schematic of a blade drive device 1 according to one embodiment of the present invention. The blade drive device 1 according to this embodiment will be described as a focal plane shutter incorporated in an optical device such as a camera, but this is merely an example, and the blade drive device according to the present invention is not limited to such shutter applications. Figure 1 shows the state when the setting operation by the camera is completed. For convenience, in this embodiment, the front side of the paper in Figure 1 will be referred to as the "front" or "forward" and the back side of the paper will be referred to as the "rear" or "rearward".

As shown in FIG. 1, the blade drive device 1 in this embodiment includes a base plate 10 with a rectangular opening, a cover plate 20 with an opening of substantially the same shape as the opening of the base plate 10, and eight blades 31 to 38 housed in a space formed between the base plate 10 and the cover plate 20. An exposure opening S is formed by the opening of the base plate 10 and the opening of the cover plate 20. 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. The imaging element is located in front of the blade drive device 1 in FIG. 1, and light from a subject passes through the exposure opening S of the base plate 10 and the cover plate 20 and enters the imaging element in front.

Figure 2 is a front view showing the state with the cover plate 20 removed. As shown in Figure 2, each of the blades 31 to 38 is a thin plate-like member extending in the X direction as a whole. In this embodiment, of the blades 31 to 38, the blades 31 to 34 that are stacked in order become the leading blades that make up the leading curtain of the focal plane shutter, and the blades 35 to 38 that are stacked in order become the trailing blades that make up the trailing curtain. An intermediate plate (not shown) is disposed between the base plate 10 and the cover plate 20, and the leading blades 31 to 34 are housed in the space formed between the intermediate plate and the cover plate 20, and the trailing blades 35 to 38 are formed in the space formed between the intermediate plate and the base plate 10.

As shown in Figure 2, the blade drive device 1 includes leading blade arms 41, 42 connected to leading blades 31-34, and trailing blade arms 43, 44 connected to trailing blades 35-38. Leading blade 31 is connected to leading blade arms 41, 42 by connecting parts 51, 52, leading blade 32 is connected to leading blade arms 41, 42 by connecting parts 53, 54, leading blade 33 is connected to leading blade arms 41, 42 by connecting parts 55, 56, and leading blade 34 is connected to leading blade arms 41, 42 by connecting parts 57, 58. These connecting parts 51-58 are formed, for example, by rivets made of relatively soft steel. By fastening these connecting portions 51-58 to rivet holes formed in the leading blade arms 41, 42, the leading blades 31-34 and the leading blade arms 41, 42 are rotatably connected to each other. In this way, the leading blades 31-34 and the leading blade arms 41, 42 form a link mechanism.

The rear blade 35 is connected to the rear blade arms 43 and 44 by connecting parts 61 and 62, the rear blade 36 is connected to the rear blade arms 43 and 44 by connecting parts 63 and 64, the rear blade 37 is connected to the rear blade arms 43 and 44 by connecting parts 65 and 66, and the rear blade 38 is connected to the rear blade arms 43 and 44 by connecting parts 67 and 68. These connecting parts 61 to 68 are formed by rivets made of relatively soft steel, for example. By fastening these connecting parts 61 to 68 to rivet holes formed in the rear blades 35 to 38, the rear blades 35 to 38 and the rear blade arms 43 and 44 are connected to each other so that they can rotate. In this way, the rear blades 35 to 38 and the rear blade arms 43 and 44 form a link mechanism.

The leading blade arm 41 is configured to be rotatable around a support shaft 71, and the leading blade arm 42 is configured to be rotatable around a support shaft 72. A drive pin 73 that is connected to a drive lever (not shown) is inserted into the leading blade arm 41. A drive mechanism (not shown) known in the art is provided behind the base plate 10, and the leading blade arm 41 rotates around the support shaft 71 by using this drive mechanism to rotate the drive lever around the support shaft 71. When the leading blade arm 41 rotates around the support shaft 71, the leading blade arm 42 also rotates around the support shaft 72 due to the link mechanism described above, and the leading blades 31 to 34 move mainly in the Y direction on the XY plane (movement plane) while changing the overlapping area.

The rear blade arm 43 is configured to be rotatable around a support shaft 81, and the rear blade arm 44 is configured to be rotatable around a support shaft 82. A drive pin 83 connected to a drive lever (not shown) is inserted into the rear blade arm 43. A drive mechanism (not shown) known in the art is provided behind the base plate 10, and the drive lever is rotated around the support shaft 81 using this drive mechanism, so that the rear blade arm 43 rotates around the support shaft 81. When the rear blade arm 43 rotates around the support shaft 81, the above-mentioned link mechanism causes the rear blade arm 44 to also rotate around the support shaft 82, and the rear blades 35 to 38 move mainly in the Y direction on the XY plane (movement plane) while changing the overlapping area.

Figure 3 is a perspective view showing the leading blade arms 41, 42. As shown in Figure 3, the leading blade arm 41 is formed, for example, by drawing or forging a metal, and includes a plate portion 100 extending along the XY plane and a shielding wall 110 extending forward (in the +Z direction) from the edge of the plate portion 100. The plate portion 100 is formed with rivet holes 120 into which the above-mentioned connecting portions 51, 53, 55, 57 (rivets) are respectively tightened, a shaft hole 130 into which the support shaft 71 is inserted, and a shaft hole 140 into which the drive pin 73 is inserted.

Similarly, the leading blade arm 42 is also formed, for example, by drawing or forging metal. As shown in FIG. 3, the leading blade arm 42 includes a plate portion 200 extending along the XY plane, and a shielding wall 210 extending forward (in the +Z direction) from the edge of the plate portion 200. The plate portion 200 is formed with rivet holes 220 into which the above-mentioned connecting portions 52, 54, 56, and 58 (rivets) are respectively fastened, and a shaft hole 230 into which the support shaft 72 is inserted.

Figures 4A and 4B are vertical cross-sectional views of the leading blade arms 42, 42, respectively. As described above, considering that the leading blade arms 41, 42 are formed by drawing or forging, the thickness T2 of the shielding walls 110, 210 of the leading blade arms 41, 42 is preferably at least one time the thickness T1 of the plate parts 100, 200, and more preferably about three times. For example, the thickness T1 of the plate parts 100, 200 of the leading blade arms 41, 42 is about 0.15 mm, and the thickness T2 of the shielding walls 110, 210 is 0.3 mm to 0.5 mm. In this embodiment, the thickness of the plate part 100 and the shielding wall 110 of the leading blade arm 41 is the same as the thickness of the plate part 200 and the shielding wall 210 of the leading blade arm 42, but these thicknesses may be different from each other.

As shown in FIG. 4A, an adhesive layer 150 is formed on the front surface (surface in the +Z direction) of the plate portion 100 of the leading blade arm 41. Similarly, as shown in FIG. 4B, an adhesive layer 250 is formed on the front surface (surface in the +Z direction) of the plate portion 200 of the leading blade arm 42. These adhesive layers 150, 250 may be formed, for example, by applying a highly viscous liquid adhesive to the plate portions 100, 200 of the leading blade arms 41, 42, or by attaching a double-sided adhesive sheet having the same shape as the plate portions 100, 200 of the leading blade arms 41, 42 to the plate portions 100, 200. As such a liquid adhesive, for example, a silicon-based liquid adhesive containing fluorine, such as Dusttrap (trademark) manufactured by Harves Co., Ltd., can be used.

When the drive lever is rotated around the support shaft 71 using the drive mechanism described above, the link mechanism causes the leading blade arm 41 to rotate around the support shaft 71, and the leading blades 31 to 34 to move in the Y direction while rotating relative to the leading blade arm 41 at the connecting parts 51, 53, 55, and 57. The link mechanism also causes the leading blade arm 42 to rotate around the support shaft 72, and the leading blades 31 to 34 to move in the Y direction while rotating relative to the leading blade arm 42 at the connecting parts 52, 54, 56, and 58. As described above, the connecting parts 51 to 58 are swaged to the rivet holes 120 and 220 of the leading blade arms 41 and 42, so it is thought that wear powder and dust will be generated when the connecting parts 51 to 58 rotate relative to the leading blade arms 41 and 42.

Here, in this embodiment, the leading blade arms 41, 42 have shielding walls 110, 210 that extend from the edges of the plate portions 100, 200 toward the imaging element (+Z direction side), so that even if wear powder or dust is generated from the connecting portions 51-58, the generated wear powder or dust can be kept in the spaces R1, R2 (see Figures 4A and 4B) inside the shielding walls 110, 210. Therefore, the generated wear powder or dust is prevented from diffusing outside the shielding walls 110, 210 of the leading blade arms 41, 42. As a result, the generated wear powder or dust is prevented from adhering to the imaging element in the camera through the opening of the cover plate 20, and a decrease in image quality can be prevented.

Furthermore, in this embodiment, adhesive layers 150, 250 are formed on the image sensor side surfaces (+Z direction surfaces) of the plate portions 100, 200 of the leading blade arms 41, 42, respectively, so that wear powder and dust present in the spaces R1, R2 inside the shielding walls 110, 210 are adsorbed and captured by the adhesive layers 150, 250. Therefore, wear powder and dust in the spaces R1, R2 inside the shielding walls 110, 210 are effectively prevented from diffusing to the outside of the shielding walls 110, 210. Note that such adhesive layers 150, 250 may also be formed on the inner peripheral surfaces of the shielding walls 110, 210.

Although not shown in the figure, the rear blade arms 43, 44 are also provided with a shielding wall and an adhesive layer, similar to the leading blade arms 41, 42. Therefore, even if wear powder or dust is generated from the connecting parts 61-68, the generated wear powder or dust can be kept in the space inside the shielding wall, and can be further adsorbed and captured by the adhesive layer. Therefore, the wear powder or dust generated from the connecting parts 61-68 is effectively prevented from diffusing to the outside of the shielding wall, and the wear powder or dust is prevented from adhering to the image sensor inside the camera through the opening in the cover plate 20.

As described above, according to the first aspect of the present invention, a blade drive device is provided that can prevent wear powder and dust generated at the connection between the blade and the arm from diffusing outside the arm. This blade drive device includes a base plate having an opening formed therein that guides light from a subject to an imaging element, at least one blade that can move on a moving plane to open and close the opening, and at least one arm connected to the at least one blade. The at least one arm has a plate portion that extends along the moving plane, and a shielding wall that extends from an edge of the plate portion toward the imaging element perpendicular to the plate portion.

As a result, even if wear powder or dust is generated at the connection between the blade and the arm, the generated wear powder or dust can be kept inside the shielding wall extending from the edge of the plate part of the arm, preventing the wear powder or dust from diffusing outside the arm.

It is preferable that the at least one arm further has an adhesive layer formed on the surface of the plate portion facing the imaging element. By forming such an adhesive layer, wear powder and dust present in the space inside the shielding wall are adsorbed and captured by the adhesive layer, effectively preventing the wear powder and dust in the space inside the shielding wall from diffusing to the outside of the shielding wall.

The at least one arm may be made of metal. The at least one arm may be formed by drawing or forging.

According to a second aspect of the present invention, there is provided an imaging device that can prevent wear debris generated at the connection between the blade and the arm from adhering to the imaging element. This imaging device includes the blade drive device described above, and an imaging element disposed on a surface where light transmitted through the opening in the base plate of the blade drive device forms an image.

With this configuration, the wear particles generated at the connection between the blade and the arm as described above are prevented from diffusing within the blade drive device, and this wear particles are prevented from adhering to the imaging element in the camera. This makes it possible to prevent a decrease in the quality of the images captured by the imaging device.

Though we have described preferred embodiments of the present invention, it goes without saying that the present invention is not limited to the above-mentioned embodiments and may be embodied in various different forms within the scope of its technical concept.

REFERENCE SIGNS LIST 1 Blade drive device 10 Base plate 20 Cover plate 31-34 Leading blade 35-38 Trailing blade 41, 42 Leading blade arm 43, 44 Trailing blade arm 51-58 Connection portion 61-68 Connection portion 71, 72, 81, 82 Support shaft 73, 83 Drive pin 100, 200 Plate portion 110, 210 Shielding wall 120, 220 Rivet hole 130, 140, 230 Shaft hole 150, 250 Adhesive layer S Exposure opening

Claims (5)

a base plate having an opening formed therein for guiding light from a subject to an image sensor;
at least one blade movable in a plane of movement to open and close the opening;
At least one arm rotatably connected to the at least one blade via a connector ,
a plate portion extending along the movement plane and to which the connecting portion is attached ;
and at least one arm having a shielding wall extending from an edge of the plate portion perpendicular to the plate portion so as to surround the connecting portion . The blade drive device according to claim 1 , wherein the at least one arm further has an adhesive layer formed on a surface of the plate portion on a side on which the shielding wall extends . The blade drive device according to claim 1 or 2, wherein at least one arm is made of metal. A method for manufacturing an arm , comprising forming the at least one arm according to any one of claims 1 to 3 by drawing or forging. The blade drive device according to any one of claims 1 to 3 ,
an imaging element disposed on a surface on which an image is formed by light transmitted through the opening of the base plate of the blade drive device.

Images