Imaging apparatus

Abstract

To allow an optical filter with various levels of light transmittance to be used in an imaging apparatus without increasing the size of the imaging apparatus.SOLUTION: An imaging apparatus has: an image pickup device 22 that includes an imaging surface 22a on which light from a subject is incident; a first filter unit 16 that includes a first electronic optical filter 24 that can change light transmittance; and a first driving mechanism 34 that rotates the first filter unit 16 centered on a first rotation center line C1 between a first filtering position and a first retreat position. The first filtering position is a position at which the first optical filter 24 is present in front of the imaging surface 22a of the image pickup device 22 and light before reaching the imaging surface 22a transmits through the first optical filter 24. The first retreat position is a position at which the first filter unit 16 is moved from the front of the imaging surface 22a.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to an imaging device.

Background Art

[0002] For example, Patent Document 1 discloses an imaging device including an ND (Neutral Density) filter unit whose light transmittance can be changed. The ND filter unit includes a plurality of ND filters having different light transmittances from each other and a rotating disk that supports the plurality of ND filters. The plurality of ND filters are provided on the rotating disk side by side in the circumferential direction around the rotation center line of the rotating disk. By rotating the rotating disk, one ND filter is disposed in front of the imaging element.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case of the imaging device described in Patent Document 1, a storage space for a plurality of unused ND filters is required, and as a result, the imaging device becomes larger.

[0005] Therefore, an object of the present disclosure is to enable an imaging device to use optical filters having various light transmittances without increasing the size of the imaging device.

Means for Solving the Problems

[0006] In order to solve the above problems, according to one aspect of the present disclosure, an imaging element including an imaging surface on which light from a subject is incident, A first filter unit comprising an electronic first optical filter with adjustable light transmittance, The first filter unit is rotated about a first rotation centerline between a first filtering position and a first retracted position, The first filtering position is a position where the first optical filter is located in front of the imaging surface of the image sensor, and the light before reaching the imaging surface passes through the first optical filter. An imaging device is provided in which the first retracted position is a position where the first filter unit is removed from the front of the imaging surface. [Effects of the Invention]

[0007] According to this disclosure, optical filters with various light transmittances can be used in an imaging device without increasing the size of the imaging device. [Brief explanation of the drawing]

[0008] [Figure 1] A schematic front perspective view of an imaging device according to one embodiment of the present disclosure. [Figure 2] Rear perspective view of the filter module [Figure 3] Decompressed rear perspective view of the filter module [Figure 4A] Rear view of the filter module in a state where the first filter unit is in the first filtering position and the second filter unit is in the second retracted position. [Figure 4B] Rear view of the filter module in a state where the first filter unit is in the first retracted position and the second filter unit is in the second filtering position. [Figure 5A] A schematic front view showing the layout of the imaging device in the embodiment. [Figure 5B] A schematic front view showing the layout of the imaging device in Comparative Example 1. [Figure 5C] A schematic front view showing the layout of the imaging device in Comparative Example 2. [Figure 6A]Rear view of the filter module in a state where the first filter unit is rotating toward the first retracted position while the second filter unit is rotating toward the second filtering position [Figure 6B] Rear view of the filter module showing the rotation states of the first and second filter units following FIG. 6A [Figure 6C] Rear view of the filter module showing the rotation states of the first and second filter units following FIG. 6B [Figure 6D] Rear view of the filter module showing the rotation states of the first and second filter units following FIG. 6C [Figure 7] Exploded rear perspective view of the first filter unit [Figure 8] Front perspective view of the ND filter assembly [Figure 9] Partial cross-sectional view of the ND filter assembly

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, a more detailed description than necessary may be omitted. For example, a detailed description of well-known matters and a redundant description of substantially the same configuration may be omitted. This is to avoid making the following description unnecessarily redundant and to facilitate the understanding of those skilled in the art.

[0010] Note that the inventor(s) provide the accompanying drawings and the following description for those skilled in the art to fully understand the present disclosure, and do not intend to limit the subject matter described in the claims thereby.

[0011] Hereinafter, an imaging device according to an embodiment of the present disclosure will be described with reference to the drawings.

[0012] FIG. 1 is a schematic front perspective view of an imaging device according to an embodiment of the present disclosure. The X - Y - Z orthogonal coordinate system shown in the figure is for facilitating the understanding of the embodiment of the present disclosure and does not limit the embodiment of the present disclosure. The X - axis direction is the front - rear direction of the imaging device, the Y - axis direction is the left - right direction, and the Z - axis direction is the height direction. Note that the side where the subject exists during shooting is defined as the front side of the imaging device.

[0013] As shown in FIG. 1, an imaging device 10 according to an embodiment of the present disclosure has a filter module 12. The imaging device 10 is a so - called single - lens reflex camera.

[0014] FIG. 2 is a rear perspective view of the filter module. Also, FIG. 3 is an exploded rear perspective view of the filter module.

[0015] As shown in FIGS. 2 and 3, in the case of this embodiment, the filter module 12 has a housing 14, a first filter unit 16, and a second filter unit 18.

[0016] The housing 14 is made of a metal material such as aluminum die - casting, etc., and supports the first and second filter units 16, 18. Also, in the case of this embodiment, the housing 14 includes a protective glass 20 through which light from the subject passes.

[0017] As shown in FIG. 2, the imaging device 10 has an imaging element 22 provided with an imaging surface 22a that faces the extending direction of the optical axis LA of the imaging device 10 (i.e., the front - rear direction (X - axis direction) of the imaging device 10) with a gap from the protective glass 20 and into which light from the subject is incident. The imaging element 22 is a photoelectric conversion element such as a CCD or a CMOS, and creates image data of the subject from the light (image of the subject) from the subject incident on the imaging surface 22a through the protective glass 20. Note that the optical axis LA is orthogonal to the imaging surface 22a of the imaging element 22 and passes through the center of the rectangular imaging surface 22a.

[0018] In this embodiment, as shown in Figures 2 and 3, the first filter unit 16 comprises a first optical filter 24 and a frame-shaped first frame structure 26 that supports the outer periphery of the first optical filter 24. The second filter unit 18 comprises a second optical filter 28 and a second frame structure 30 that supports the outer periphery of the second optical filter 28.

[0019] In this embodiment, the first optical filter 24 is an electronic ND filter with adjustable light transmittance, such as a liquid crystal filter. By changing the drive voltage applied to the first optical filter 24, the light transmittance of the first optical filter 24 is changed. The second optical filter 28 is a filter with fixed light transmittance, such as glass. In this embodiment, the first and second optical filters 24 and 28 are rectangular in shape, similar to the imaging surface 22a of the image sensor 22.

[0020] The first frame structure 26, which supports the first filter unit 16, i.e., the first optical filter 24, is supported on the housing 14 so as to be rotatable about a first rotation centerline C1 extending in the front-to-back direction (X-axis direction) of the imaging device 10. The second frame structure 30, which supports the second filter unit 18, i.e., the second optical filter 28, is supported on the housing 14 so as to be rotatable about a second rotation centerline C2 extending in the front-to-back direction of the imaging device 10.

[0021] In this embodiment, as shown in Figures 2 and 3, the first and second rotation centerlines C1 and C2 are located on the same straight line. Therefore, the first filter unit 16 rotates forward relative to the second filter unit 18. Because the first and second rotation centerlines C1 and C2 are located on the same straight line, the support shaft 32 that rotatably supports the first and second filter units 16 and 18 can be made common.

[0022] As shown in Figure 3, the filter module 12 includes a first drive mechanism 34 that rotates the first filter unit 16 about a first rotation centerline C1, and a second drive mechanism 36 that rotates the second filter unit 18 about a second rotation centerline C2.

[0023] In this embodiment, the first and second drive mechanisms 34 and 36 are so-called rack and pinion mechanisms.

[0024] The first drive mechanism 34 includes a first rack 38 that extends in the left-right direction (Y-axis direction) of the imaging device 10 and is supported by the housing 14 so as to be movable in that direction, and a first drive gear 40 that engages with the first rack 38 and moves in the left-right direction. The first rack 38 engages with a pinion portion 26a formed on the first frame structure 26 of the first filter unit 16. As the first rack 38 moves in the left-right direction due to the rotation of the first drive gear 40, the pinion portion 26a rotates about the first rotation centerline C1. As a result, the first filter unit 16 rotates about the first rotation centerline C1.

[0025] The second drive mechanism 36 includes a second rack 42 that extends in the left-right direction (Y-axis direction) of the imaging device 10 and is supported by the housing 14 so as to be movable in that direction, and a second drive gear 44 that engages with the second rack 42 and moves it in the left-right direction. The second rack 42 extends rearward and parallel to the first rack 38. The second rack 42 also engages with a pinion portion 30a formed on the second frame structure 30 of the second filter unit 18. As the second rack 42 moves in the left-right direction due to the rotation of the second drive gear 44, the pinion portion 28a rotates about the second rotation centerline C2. As a result, the second filter unit 18 rotates about the second rotation centerline C2.

[0026] The first drive mechanism 34 causes the first filter unit 16 to rotate around the first rotation centerline C1 between the first filtering position and the first retracted position. The second drive mechanism 36 causes the second filter unit 18 to rotate around the second rotation centerline C2 between the second filtering position and the second retracted position.

[0027] Figure 4A is a rear view of the filter module in a state where the first filter unit is in the first filtering position and the second filter unit is in the second retracted position. Figure 4B is a rear view of the filter module in a state where the first filter unit is in the first retracted position and the second filter unit is in the second filtering position.

[0028] As shown in Figure 4A, the first filter unit 16 is rotated by the first drive mechanism 34 to be positioned in the first filtering position. Specifically, when the first filter unit 16 is in the first filtering position, the first optical filter 24 is located in front of the imaging surface 22a of the image sensor 22. As a result, light from the subject passes through the first optical filter 24 before reaching the imaging surface 22a through the protective glass 20. Consequently, light from the subject that has been filtered by the first optical filter 24 is incident on the imaging surface 22a.

[0029] Furthermore, as shown in Figure 4B, the first filter unit 16 is rotated by the first drive mechanism 34 and positioned in a first retracted position. Specifically, the first filter unit 16 is retracted to a position away from the front of the imaging surface 22a of the image sensor 22 as its first retracted position. In this embodiment, the first filter unit 16 is retracted to the left from the front of the imaging surface 22a (when viewed from the front of the imaging device 10). As a result, light from the subject is incident on the imaging surface 22a without being obstructed by the first filter unit 16, that is, without passing through the first optical filter 24.

[0030] As shown in Figure 4B, the second filter unit 18 is rotated by the second drive mechanism 36 to be positioned at the second filtering position. Specifically, when the second filter unit 18 is in the second filtering position, the second optical filter 28 is located in front of the imaging surface 22a of the image sensor 22. Light from the subject passes through the second optical filter 28 before reaching the imaging surface 22a after passing through the protective glass 20. As a result, the light from the subject that has been filtered by the second optical filter 28 is incident on the imaging surface 22a. The second filtering position is located behind the first filtering position.

[0031] Furthermore, as shown in Figure 4A, the second filter unit 18 is rotated by the second drive mechanism 36 and positioned in a second retracted position. Specifically, the second filter unit 18 retracts to a position away from the front of the imaging surface 22a of the image sensor 22 as the second retracted position. In this embodiment, the second filter unit 18 retracts to the left from the front of the imaging surface 22a (when viewed from the front of the imaging device 10). As a result, light from the subject enters the imaging surface 22a without being obstructed by the second filter unit 18, that is, without passing through the second optical filter 28. Note that the second retracted position is located behind the first retracted position.

[0032] In this embodiment, as shown in Figure 4B, the first filter unit 16 is rotated substantially 90 degrees around the first rotation centerline C1 by the first drive mechanism 34. Therefore, the positional relationship between the first filtering position and the first retracted position is such that when the first filter unit 16 located in one of the first filtering position and the first retracted position is rotated 90 degrees, it is positioned in the other position. As a result, the orientation of the first optical filter 24 (24') of the first filter unit 16 located in the first filtering position (dotted line) and the orientation of the first optical filter 24 when located in the first retracted position (solid line) differ by 90 degrees. That is, the longitudinal direction of the first optical filter 24 changes from the left-right direction (Y-axis direction) of the imaging device 10 to the height direction (Z-axis direction).

[0033] Furthermore, the first rotation centerline C1 of the first filter unit 16 is positioned such that the first optical filter 24 (24') located in the first filtering position and the first optical filter 24 located in the first retracted position are adjacent to each other as much as possible without overlapping. For example, in this embodiment, the first rotation centerline C1 is positioned so as not to pass through the first optical filter 24, and near the lower left corner of the first optical filter 24 (24') when it is in the first filtering position (when viewed from the front of the imaging device 10).

[0034] This first rotational centerline C1 allows the movement range of the first optical filter 24, i.e., the first filter unit 16, to be reduced compared to the case where the first optical filter 24 moves parallel to the left-right direction (Y-axis direction) of the imaging device 10. As a result, an increase in the size of the imaging device 10, particularly in the left-right direction, can be suppressed. Furthermore, a decrease in the aesthetic design of the imaging device 10 due to an increase in size in the left-right direction can be suppressed.

[0035] Furthermore, if the first optical filter 24 is moved in the height direction (Z-axis direction) of the imaging device 10, which is its shorter side, it would be necessary to increase the size of the imaging device 10 in the height direction, or to miniaturize the first optical filter 24, i.e., to miniaturize the image sensor 22. However, in that case, the design or performance of the imaging device 10 would be greatly impaired.

[0036] I will add some details regarding the design of the imaging device 10.

[0037] Figure 5A is a schematic front view showing the layout of the imaging device in the embodiment. Figure 5B is a schematic front view showing the layout of the imaging device in Comparative Example 1. Furthermore, Figure 5C is a schematic front view showing the layout of the imaging device in Comparative Example 2.

[0038] Figures 5A to 5C schematically show the layouts for the cases where the first filter unit 16 is rotated 90 degrees (Example 1), where the first filter unit 16 is translated in the left-right direction (Y-axis direction) of the imaging device (Comparative Example 1), and where the first filter unit 16 is translated in the height direction (Z-axis direction) (Comparative Example 2).

[0039] As shown in Figure 5A, the imaging device 10 is broadly divided into a main body 10a and a grip 10b when viewed from the front. The front silhouette (contour shape when viewed from the front) of the main body 10a greatly influences the design of the imaging device 10. For example, if the imaging device 10 is designed like a so-called single-lens reflex camera, it is preferable that the size r1 of the imaging device 10 in the left-right direction (Y-axis direction) of the main body 10a is approximately 1.2 to 1.8 times the size r2 in the height direction (Z-axis direction). It is necessary to house the image sensor 22, components related to the image sensor 22, and the first filter unit 16 within the main body 10a while maintaining the design of the front silhouette of the main body 10a of the imaging device 10. A battery (not shown) is housed in the grip 10b.

[0040] As shown in Figure 5A, the front silhouette of the main body 10a of the imaging device 10 is rectangular in shape, with the size r1 in the left-right direction (Y-axis direction) being larger than the size r2 in the height direction (Z-axis direction). Furthermore, considering the aesthetic design of the imaging device 10, the optical axis LA of the imaging device 10 passes through the center of this rectangular front silhouette of the main body 10a.

[0041] Furthermore, the main body 10a of the imaging device 10 must include a storage area SA for components related to the image sensor 22. Components related to the image sensor 22 include, for example, a substrate on which the image sensor 22 is mounted, and a cooling device for cooling the image sensor 22. In addition, if the imaging device 10 has an image stabilization function, actuators that displace the image sensor 22 in the left-right direction (Y-axis direction) and the height direction (Z-axis direction) of the imaging device 10 are included as components related to the image sensor 22. Therefore, the storage area SA has a predetermined positional relationship and predetermined size with respect to the image sensor 22.

[0042] Furthermore, the movement range MA (hatched portion) of the first filter unit 16, which rotates substantially 90 degrees around the first rotation centerline C1, must be included within the main body 10a of the imaging device 10.

[0043] Let s1 and s2 be the left-right (Y-axis direction) and height (Z-axis direction) dimensions of the imaging device 10 of the first filter unit 16 when it is positioned at the first filtering position. In this case, the left-right and height dimensions m1 and m2 of the movement range MA of the first filter unit 16 can be expressed by equations 1 and 2.

number

number

[0044] The dimensions r1 and r2 of the main body 10a in the left-right direction (Y-axis direction) and height direction (Z-axis direction), which are necessary to include the storage area SA and the movement range MA, can be expressed by equations 3 and 4.

number

number

[0045] In the case of the imaging device 110 of Comparative Example 1 shown in Figure 5B, the first filter unit 16 does not rotate but moves in parallel to the left and right direction (Y-axis direction) of the imaging device 10. When retracting from the front of the image sensor 22, the first filter unit 16 moves in parallel to the left side of the main body 110a. Note that since the battery is located in the grip portion 110b, the first filter unit 16 cannot move into the grip portion 110b.

[0046] In the case of the imaging device 110 of Comparative Example 1 shown in Figure 5B, the left-right (Y-axis direction) and height (Z-axis direction) dimensions m3 and m4 of the movement range MA of the first filter unit 16 can be expressed by equations 5 and 6. Furthermore, the left-right dimension r3 of the main body 10a necessary to contain the storage area SA and the movement range MA can be expressed by equation 7.

number

number

number

[0047] Furthermore, in the case of the imaging device 210 of Comparative Example 2 shown in Figure 5C, the first filter unit 16 moves parallel to the height direction (Z-axis direction) of the imaging device 210 without rotating. When retracting from the front of the image sensor 22, the first filter unit 16 moves parallel to the upper side of the main body 110a.

[0048] In the case of the imaging device 210 of Comparative Example 2 shown in Figure 5C, the left-right (Y-axis direction) and height (Z-axis direction) dimensions m5 and m6 of the movement range MA of the first filter unit 16 can be expressed by equations 8 and 9. Furthermore, the height dimension r4 of the main body 210a necessary to include the storage area SA and the movement range MA can be expressed by equation 10.

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[0049] As shown in Figures 5A to 5C, when the first filter unit 16 rotates 90 degrees around the first rotation centerline C1, the area of ​​the movement range MA required for that movement is larger than when it moves in parallel in the left-right direction (Y-axis direction) or the height direction (Z-axis direction).

[0050] However, the left-right size m1 of the movement range MA required for the first filter unit 16 to rotate 90 degrees in the embodiment is smaller than the left-right size m3 of the movement range MA of the first filter unit 16 in Comparative Example 1, that is, smaller than twice the left-right size s1 of the first filter unit 16. Also, the height-direction size m2 of the movement range MA of the first filter unit 16 in the embodiment is smaller than the height-direction size m6 of the movement range MA of the first filter unit 16 in Comparative Example 2, that is, smaller than twice the height-direction size s2 of the first filter unit 16.

[0051] As a result, as shown in Figures 5A to 5C, in the embodiment where the first filter unit 16 rotates 90 degrees around the first rotation center line C1, the impact on the design of the imaging device is less compared to Comparative Examples 1 and 2, where the first filter unit 16 moves in parallel in the left-right direction (Y-axis direction) or the height direction (Z-axis direction). In other words, the imaging device can obtain the design of a so-called single-lens reflex camera. In the case of Comparative Example 1, the main body 110a of the imaging device 110 has an extremely long rectangular front silhouette in the left-right direction, which deviates from the design of a single-lens reflex camera. Also, in the case of Comparative Example 2, the main body 210 of the imaging device 210 has a front silhouette that is close to a square, which deviates from the design of a single-lens reflex camera.

[0052] In this embodiment, as shown in Figure 4B, the second filter unit 18 is rotated substantially 90 degrees around the second rotation centerline C2 by the second drive mechanism 36. Therefore, the positional relationship between the second filtering position and the second retracted position is such that when the second filter unit 18 located in one of the second filtering position and the second retracted position is rotated 90 degrees, it is positioned in the other position. As a result, the orientation of the second optical filter 28 of the second filter unit 18 located in the second filtering position (solid line) and the orientation of the second optical filter 28 (28') when located in the second retracted position (dotted line) differ by 90 degrees. That is, the longitudinal direction of the second optical filter 28 changes from the left-right direction (Y-axis direction) of the imaging device 10 to the height direction (Z-axis direction).

[0053] Furthermore, the second rotation centerline C2 of the second filter unit 18 is positioned such that the second optical filter 28 located in the second filtering position and the second optical filter 28(28') located in the second retracted position are adjacent to each other as much as possible without overlapping. For example, in this embodiment, the second rotation centerline C2 is positioned so as not to pass through the second optical filter 28, and near the lower left corner of the second optical filter 28 when it is in the second filtering position (when viewed from the front of the imaging device 10).

[0054] This second rotational centerline C2 allows the movement range of the second optical filter 28, or second filter unit 18, to be reduced compared to the case where the second optical filter 28 moves parallel to the left-right direction (Y-axis direction) of the imaging device 10. As a result, an increase in the size of the imaging device 10, particularly in the left-right direction, can be suppressed. Furthermore, a decrease in the aesthetic design of the imaging device 10 due to an increase in size in the left-right direction can be suppressed.

[0055] Furthermore, if the second optical filter 28 is moved in the vertical direction (Z-axis direction) of the imaging device 10, which is its shorter side, it would be necessary to increase the size of the imaging device 10 in the vertical direction, or to miniaturize the second optical filter 28, i.e., to miniaturize the image sensor 22. However, in that case, the design or performance of the imaging device 10 would be greatly impaired.

[0056] Since the second filter unit 18 rotates substantially 90 degrees, just like the first filter unit 16, it does not significantly affect the design of the imaging device 10 compared to when it is moved in parallel in the left-right direction (Y-axis direction) or the height direction (Z-axis direction).

[0057] In other words, the lateral movement range of the second filter unit 18 required to rotate 90 degrees around the second rotation centerline C2 is smaller than twice the lateral size of the second filter unit 18 when it is in the second filtering position. Also, the height range of the second filter unit is smaller than twice the height size of the second filter unit 18 when it is in the second filtering position. As a result, the imaging device 10 can be designed like a so-called single-lens reflex camera.

[0058] In this embodiment, the rotational movement of the first filter unit 16 by the first drive mechanism 34 and the rotational movement of the second filter unit 18 by the second drive mechanism 36 are synchronized.

[0059] Specifically, as shown in Figure 4A, the rotational movements of the first and second filter units 16 and 18 are synchronized so that when the first filter unit 16 is in the first filtering position (i.e., in front of the imaging surface 22a of the image sensor 22), the second filter unit 18 is in the second retracted position (i.e., away from the front of the imaging surface 22a). Also, as shown in Figure 4B, the rotational movements of the first and second filter units 16 and 18 are synchronized so that when the first filter unit 16 is in the first retracted position, the second filter unit 18 is in the second filtering position. To achieve this, the first drive mechanism 34 and the second drive mechanism 36 are synchronized.

[0060] In this embodiment, as shown in Figures 2 and 3, the first drive gear 40 of the first drive mechanism 34 and the second drive gear 44 of the second drive mechanism 36 engage with each other. The second drive gear 44 is engaged with a power transmission gear 46, which is a power source that supplies power to the first drive mechanism 34 and the second drive mechanism 36. This power transmission gear 46 is located on the front of the imaging device 10 and is connected to a rotary knob 48 that is rotated by the user.

[0061] When the user rotates the rotary knob 48 from the state shown in Figure 4A, the power transmission gear 46 rotates, causing the first drive gear 40 and the second drive gear 44 to rotate synchronously. As a result, the first rack 38, which engages with the first drive gear 40, moves to the right (when viewed from the front of the imaging device 10), and the second rack 42, which engages with the second drive gear 44, moves in the opposite direction, i.e., to the left. As the first rack 38 and the second rack 42 move in opposite directions, the first filter unit 16 and the second filter unit 18 rotate in opposite directions.

[0062] Figures 6A to 6D are rear views of the filter module in a state where the first filter unit is rotating toward the first retracted position and the second filter unit is rotating toward the second filtering position.

[0063] As shown in Figures 6A to 6D, when the user rotates the rotary knob 48 in the forward direction from the state shown in Figure 4A, the first filter unit 16 rotates from the first filtering position toward the first retracted position, while the second filter unit 18 rotates from the second retracted position toward the second filtering position. During the rotation, the first filter unit 16 and the second filter unit 18 overlap in the front-to-back direction (X-axis direction) of the imaging device 10. In this embodiment, the second filter unit 18 passes behind the first filter unit 16.

[0064] When the user reverses the rotation knob 48 from the state shown in Figure 4B, the first filter unit 16 rotates from the first retracted position toward the first filtering position, while the second filter unit 18 rotates from the second filtering position toward the second avoidance position.

[0065] The synchronous operation of the first drive mechanism 34 and the second drive mechanism 36 allows the first filter unit 16 and the second filter unit 18 to be rotated simultaneously by simply rotating a single rotary knob 48. In other words, the user can position the first optical filter 24 or the second optical filter 28 in front of the imaging surface 22a of the image sensor 22 simply by rotating the rotary knob 48 in the forward or reverse direction. As a result, the user can easily change the optical filter used from the first optical filter 24 to the second optical filter 28, or vice versa.

[0066] In this embodiment, the first optical filter 24 is an electronic ND filter with adjustable light transmittance, and the second optical filter 28 is a filter with fixed light transmittance, such as glass. To ensure that the focus does not change when switching from the first optical filter 24 to the second optical filter 28, the second optical filter 28 has substantially the same optical path length as the first optical filter 24.

[0067] In this embodiment, the imaging device 10 also includes a sensor unit 50 that detects the light transmittance of the first optical filter 24.

[0068] Figure 7 is an exploded rear perspective view of the first filter unit. Figure 8 is a front perspective view of the ND filter assembly. And Figure 9 is a partial cross-sectional view of the ND filter assembly.

[0069] As shown in Figures 7 to 9, the sensor unit 50 is provided in the first filter unit 16. The sensor unit 50 includes a light source 52 such as an LED, a light guide member 54 that spectrally analyzes the light output from the light source 52 and emits first and second optics L1 and L2, a first optics sensor 56 that detects the intensity of the first optics L1, and a second optics sensor 58 that detects the intensity of the second optics L2.

[0070] In this embodiment, the first optical filter 24 in the first filter unit 16 is provided between the glass plates 60 and 62, and between the glass plates 64 and 66, respectively. One first light, L1, passes through the two first optical filters 24 and the four glass plates 60 to 66 and enters the first light sensor 56. The other second light, L2, passes through only the glass plates 62 and 64 and enters the second light sensor 58.

[0071] When the light transmittance of the first optical filter 24 is a predetermined light transmittance (i.e., when the drive voltage applied to the first optical filter 24 is a predetermined voltage), the intensity difference between the intensity of the first light L1 and the intensity of the second light L2 detected by the first optical sensor 56 is a predetermined intensity difference. If the intensity difference between the first light L1 and the second light L2 differs from the predetermined intensity difference despite the drive voltage of the first optical filter 24 being a predetermined voltage, it can be determined that an abnormality such as deterioration or failure has occurred in the first optical filter 24.

[0072] In this embodiment, the sensor unit 50 is provided on the first filter unit 16. Therefore, the sensor unit 50 can detect the light transmittance of the first optical filter 24 regardless of the position of the first filter unit 16.

[0073] According to this embodiment, it becomes possible to use optical filters with various light transmittances in the imaging device without increasing the size of the imaging device.

[0074] Specifically, unlike this embodiment, when using multiple optical filters with different light transmittances, space is required to retract the remaining optical filters that are not being used. In contrast, according to this embodiment, since the first optical filter 24 is a single electronic filter with adjustable light transmittance, less space is required for retraction.

[0075] Furthermore, in this embodiment, the rectangular first optical filter 24 is rectangular and rotates 90 degrees toward the first retracted position. This makes it possible to suppress an increase in the size of the imaging device 10 in the left-right direction (Y-axis direction) compared to when the first optical filter 24 is retracted by moving parallel to its longitudinal direction (Y-axis direction).

[0076] Furthermore, in this embodiment, as shown in Figures 4A and 4B, the second retracted position of the second optical filter 28 (second filter unit 18) is located behind the first retracted position of the first optical filter 24 (first filter unit 16), that is, they are aligned in the front-to-back direction (X-axis direction) of the imaging device 10. As a result, compared to the case where the first and second retracted positions are aligned in the left-to-right direction (Y-axis direction) or the height direction (Z-axis direction) of the imaging device 10, a decrease in the aesthetic design of the imaging device 10, or the aesthetic design of a single-lens reflex camera, can be suppressed.

[0077] Although embodiments of this disclosure have been described above with reference to the embodiments described above, the embodiments of this disclosure are not limited to the embodiments described above.

[0078] For example, in the embodiment described above, as shown in Figure 3, the imaging device 10 has a second optical filter 28 made of glass or the like, whose light transmittance cannot be changed. Furthermore, the second optical filter 28 has substantially the same optical path length as the first optical filter 24. This makes it possible to maintain focus even when changing from the first optical filter 24 to the second optical filter 28. However, the embodiments of this disclosure are not limited to this. If the focus can be maintained by another mechanism even when the first optical filter 24 is moved away from the first filtering position (the position in front of the imaging surface 22a of the image sensor 22), then the second optical filter 28, i.e., the second filter unit 18, can be omitted.

[0079] Furthermore, in the above-described embodiment, as shown in Figure 3, the first and second drive mechanisms 34 and 36 that rotate the first and second filter units 16 and 18 are so-called rack and pinion mechanisms. However, the embodiments of this disclosure are not limited to this. For example, two motors may rotate the first and second filter units 16 and 18, respectively.

[0080] Furthermore, in the above-described embodiment, the first and second filter units 16 and 18 are rotated by the user by rotating the rotary knob 48, i.e., manually. However, the embodiments of this disclosure are not limited thereto. For example, when the user presses a button, a motor may rotate the first and second filter units 16 and 18.

[0081] Furthermore, in the above-described embodiment, as shown in Figures 7 to 9, the sensor unit 50 for detecting the light transmittance of the first optical filter 24 is provided on the first filter unit 16. However, the embodiments of this disclosure are not limited to this. The sensor unit 50 may be provided on the housing 14 of the filter module 12. In this case, the sensor unit 50 is provided at a position on the housing 14 where the light transmittance of the first optical filter 24 can be detected when the first filter unit 16 is in the first filtering position (Figure 4A).

[0082] In other words, the imaging device according to the embodiment of the present disclosure broadly comprises an image sensor having an imaging surface into which light from a subject is incident, a first filter unit having an electronic first optical filter whose light transmittance can be changed, and a first drive mechanism that rotates the first filter unit between a first filtering position and a first retracted position about a first rotation center line, wherein the first filtering position is a position in front of the imaging surface of the image sensor where the first optical filter is located and the light before reaching the imaging surface passes through the first optical filter, and the first retracted position is a position where the first filter unit is moved away from the front of the imaging surface.

[0083] As described above, the embodiments described in this disclosure have been explained as examples of the technology. For this purpose, drawings and a detailed description are provided. Therefore, among the components described in the drawings and detailed description, there may be not only components that are essential for solving the problem, but also components that are not essential for solving the problem, in order to illustrate the technology described above. For this reason, the mere fact that these non-essential components are described in the drawings and detailed description should not be immediately assumed to be essential.

[0084] Furthermore, since the embodiments described above are for illustrative purposes of the technology described herein, various modifications, substitutions, additions, omissions, etc., can be made within the scope of the claims or equivalents thereof. [Industrial applicability]

[0085] This disclosure is applicable to imaging devices that include multiple ND filters with different light transmittances. [Explanation of Symbols]

[0086] 16. First filter unit 22 Imaging elements 22a Imaging surface 24. First optical filter 34 First drive mechanism C1 First rotation centerline

Claims

1. an imaging element having an imaging surface onto which light from a subject is incident; a first filter unit including a first optical filter; a first drive mechanism that rotates the first filter unit about a first rotation center line between a first filtering position and a first retracted position; the first filtering position is a position where the first optical filter is present in front of the imaging surface of the imaging element, and the light before reaching the imaging surface passes through the first optical filter; The imaging device, wherein the first retracted position is a position where the first filter unit is out of front of the imaging surface.

2. the first filter unit is rotated 90 degrees by the first driving mechanism, The first optical filter has a rectangular shape, a positional relationship between the first filtering position and the first retracted position in which the first filter unit located at one of the first filtering position and the first retracted position is rotated by 90 degrees to be located at the other position, 2. The imaging device of claim 1, wherein the first rotation center line is positioned so that the first optical filter of the first filter unit located at the first filtering position and the first optical filter of the first filter unit located at the first retracted position are adjacent to each other.

3. a size in the left-right direction of the imaging device of a movement range of the first filter unit necessary for rotating the first filter unit 90 degrees around the first rotation center line is smaller than twice the size in the left-right direction of the first filter unit when the first filter unit is located at the first filtering position, 3. The imaging device of claim 2, wherein the height direction size of the imaging device of the movement range of the first optical filter unit is smaller than twice the height direction size of the first filter unit when the first filter unit is positioned at the first filtering position.

4. a second filter unit including a second optical filter having a fixed light transmittance; a second drive mechanism for rotating the second filter unit about a second rotation center line between a second filtering position and a second retracted position, the second filtering position is a position where the second optical filter is present in front of the imaging surface of the imaging element, and the light before reaching the imaging surface passes through the second optical filter; The imaging device according to claim 1 , wherein the second retracted position is a position where the second filter unit is out of front of the imaging surface.

5. the second filter unit is rotated 90 degrees by the second driving mechanism, the second optical filter is rectangular, a positional relationship between the second filtering position and the second retracted position in which the second filter unit located at one of the second filtering position and the second retracted position is rotated by 90 degrees to be located at the other position, 5. The imaging device of claim 4, wherein the second rotation center line is positioned so that the second optical filter of the second filter unit located at the second filtering position and the second optical filter of the second filter unit located at the second retracted position are adjacent to each other.

6. a size in the left-right direction of a movement range of the second filter unit required for rotating the second filter unit 90 degrees about the second rotation center line is smaller than twice the size in the left-right direction of the second filter unit when the second filter unit is located at the second filtering position, 6. The imaging device of claim 5, wherein the height-wise size of the movement range of the second filter unit is smaller than twice the height-wise size of the second filter unit when the second filter unit is positioned at the second filtering position.

7. The imaging device according to claim 4 , wherein the second optical filter has an optical path length that is the same as an optical path length of the first optical filter.

8. 8. The imaging device according to claim 4, wherein the first driving mechanism and the second driving mechanism are synchronized such that when the first filter unit is located at the first filtering position, the second filter unit is located at the second retracted position, and when the first filter unit is located at the first retracted position, the second filter unit is located at the second filtering position.

9. The imaging apparatus according to claim 8 , further comprising a common power source that supplies power to the first drive mechanism and the second drive mechanism.

10. The imaging device of claim 9 , wherein the power source is a rotatable knob that is operated by a user.

11. The imaging device according to claim 4 , wherein the first rotation center line and the second rotation center line are positioned on the same straight line.

12. the first and second drive mechanisms are rack and pinion mechanisms, the first drive mechanism includes a first rack that is formed in the first filter unit and engages with a pinion portion that rotates about the first rotation center line; 12. The imaging device according to claim 4, wherein the second drive mechanism includes a second rack that engages with a pinion portion formed in the second filter unit and that rotates about the second rotation center line.

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