Imaging apparatus

Abstract

To provide an imaging apparatus capable of shortening a back focus, in an imaging apparatus including a filter inserting and removing mechanism.SOLUTION: The imaging apparatus includes a lens holder which has an opening and holds a lens and a filter holder which holds a filer so that it can be inserted / removed into / from the optical path of the lens. At least a part of at least one of the filter and the filter holder is arranged in the opening so as to overlap with at least a part of the lens holder, when viewed from a direction orthogonal to the optical axis direction of the lens.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an imaging device equipped with a filter insertion / removal mechanism. [Background technology]

[0002] Conventionally, imaging devices equipped with a filter insertion / removal mechanism for inserting and removing a filter such as an IR cut filter so that imaging can be performed even in a low-illumination environment are widely known. The filter insertion / removal mechanism is disposed in front of the imaging element. Therefore, it is necessary to extend the back focus by the thickness of the filter insertion / removal mechanism in the optical axis direction, which leads to an increase in the size of the imaging device.

[0003] As a technique for a filter insertion / removal mechanism, the technique disclosed in Patent Document 1 is one in which a filter moving frame that holds a filter is disposed outside the optical path, and the thickness of a member disposed within the optical path is reduced, thereby shortening the back focus. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-33594 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technique of Patent Document 1 does not take into consideration the positional relationship between the lens holding frame that holds the lens and the filter holding frame that holds the filter, which may result in a long back focus.

[0006] The present invention provides an image pickup apparatus having a filter inserting / removing mechanism, which can shorten the back focus. [Means for solving the problem]

[0007] The imaging device of the present embodiment includes a lens holder having an opening and configured to hold a lens, and a filter holder configured to hold a filter in an optical path of the lens so that the filter can be inserted and removed therefrom; The filter holder or at least one of the filter holders is characterized in that at least a portion of the filter holder is disposed in the opening so as to overlap at least a portion of the lens holder when viewed from a direction perpendicular to the optical axis direction of the lens. Effect of the Invention

[0008] According to the present invention, it is possible to provide an image pickup apparatus having a filter insertion / removal mechanism that can shorten the back focus. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of an imaging device according to a first embodiment. [Diagram 2] FIG. 1 is an exploded perspective view of an imaging device according to a first embodiment. [Diagram 3] FIG. 1 is a perspective view of a filter unit 20 according to a first embodiment. [Figure 4] FIG. 1 is a detailed exploded perspective view of a filter unit 20 according to a first embodiment. [Diagram 5] Detailed exploded cross-sectional side view of embodiment 1 [Figure 6] FIG. 13 is a perspective view of a filter unit 20 according to a second embodiment. [Figure 7] Detailed exploded cross-sectional side view of embodiment 2 [Figure 8] FIG. 13 is an exploded perspective view of the filter unit 20 according to the third embodiment. [Figure 9] FIG. 13 is a detailed exploded perspective view of the filter unit 20 according to the third embodiment. [Figure 10] Detailed exploded cross-sectional side view of embodiment 3 [Figure 11] FIG. 13 is a perspective view of a filter unit 20 according to a fourth embodiment. [Figure 12] FIG. 13 is a detailed exploded perspective view of the filter unit 20 according to the fourth embodiment. [Figure 13] Detailed exploded cross-sectional side view of embodiment 4 [Figure 14]FIG. 13 is a perspective view of a filter unit 20 according to a fifth embodiment. [Figure 15] FIG. 13 is a detailed exploded perspective view of the filter unit 20 according to the fifth embodiment. [Figure 16] Detailed exploded cross-sectional side view of embodiment 5 [Figure 17] FIG. 13 is a perspective view of a filter frame according to a fifth embodiment. [Figure 18] FIG. 13 is a perspective view of a second filter holder according to a fifth embodiment; [Figure 19] Cross-sectional view of the filter unit and its surroundings according to the fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <Embodiment 1> Hereinafter, an imaging device according to a first embodiment of the present invention will be described with reference to FIGS.

[0011] FIG. 1 is a perspective view of the imaging device of the first embodiment. FIG. 2 is an exploded perspective view of the imaging device of the first embodiment. FIG. 3 is a perspective view of the filter frame of the first embodiment. The imaging device is composed of a lens barrel 1 and an imaging unit 30. The lens barrel 1 has a lens unit 10 and a filter unit 20. FIG. 4 is a front view (viewed from the subject side) of the four-group lens holder of the first embodiment. FIG. 5 is a rear view of the filter unit and its surroundings when the filter of the first embodiment is in the optical path. FIG. 6 is a rear view of the filter unit and its surroundings when the filter of the first embodiment is out of the optical path. FIG. 7 is a cross-sectional view of the filter unit and its surroundings of the first embodiment.

[0012] The lens unit 10 has an imaging optical system including, in order from the subject side, a first lens group 110, a second lens group 120, a third lens group 130, and a fourth lens group 140. The lens unit 10 further has a front sleeve 150 and a rear sleeve (fourth lens holder 141), and the front sleeve 150 and the rear sleeve form a housing.

[0013] The first lens group 110 is held by a first lens holder 111. The first lens holder 111 is engaged with a guide bar 151 and supported so as to be movable in the optical axis direction of the imaging optical system. The first lens holder 111 is also engaged with a guide bar 152, and rotation around the guide bar 151 is restricted.

[0014] Furthermore, the first lens holder 111 holds a first group rack 112. The first group rack 112 is engaged with a lead screw portion of a first group drive unit 113 that includes an actuator such as a stepping motor. When the lead screw portion is rotated by the first group drive unit 113, the first lens holder 111 moves together with the first group rack 112 in the optical axis direction of the imaging optical system.

[0015] The second lens group 120 is held by a second lens holder 121. The second lens holder 121 is engaged with a guide bar 153 and supported so as to be movable in the optical axis direction of the imaging optical system. The second lens holder 121 is also engaged with a guide bar 154, and rotation around the guide bar 153 is restricted.

[0016] Further, the second lens holder 121 holds a second group rack 122. The second group rack 122 is engaged with a lead screw portion of a second group drive unit 123 that includes an actuator such as a stepping motor. When the lead screw portion is rotated by the second group drive unit 123, the second lens holder 121 moves together with the second group rack 122 in the optical axis direction of the imaging optical system.

[0017] The third lens group 130 is held by a third lens holder 131. The third lens holder 131 is engaged with a guide bar 153 and supported so as to be movable in the optical axis direction of the imaging optical system. The third lens holder 131 is also engaged with a guide bar 154, and rotation around the guide bar 153 is restricted.

[0018] Further, the third lens holder 131 holds a third group rack 132. The third group rack 132 is engaged with a lead screw portion of a third group drive unit 133 that includes an actuator such as a stepping motor. When the lead screw portion is rotated by the third group drive unit 133, the third lens holder 131 moves together with the third group rack 132 in the optical axis direction of the imaging optical system.

[0019] The fourth lens group 140 is held by a fourth lens holder 141. The fourth lens holder 141 will be described in detail later.

[0020] The guide bars 151, 152, 153, and 154 are held by the front sleeve 150 and the fourth lens holder 141. In addition, the first group driving section 113, the second group driving section 123, and the third group driving section 133 are fixed to the fourth lens holder 141.

[0021] Zooming and focusing of the imaging optical system are performed by moving the first lens group 110, the second lens group 120, and the third lens group 130 in the optical axis direction of the imaging optical system in a predetermined positional relationship. Note that the lens configuration of the lens unit 10 is not limited to the above.

[0022] The filter unit 20 has a filter 21, a filter frame 22, and a filter driver 23 (FIG. 5). The filter 21 is an optical filter such as an IR cut filter. A diagonal length 21a of the filter 21 is smaller than a diameter 140b of a lens 140a of the fourth lens group 140 that is closest to the filter 21 in the optical axis direction. With this configuration, the area through which the filter 21 and a filter holding part 22a described later pass when inserted into or removed from the optical path becomes smaller as viewed from the optical axis direction, making it easier to ensure a space for molding a lens holding part 141a described later of the fourth lens holder 141.

[0023] The filter frame 22 holds the filter 21. The filter frame 22 has a filter holding portion 22a, and the filter 21 abuts against the filter holding portion 22a. The filter frame 22 has a groove portion 22b, and the filter 21 is fixed to the filter frame 22 by applying an adhesive to the groove portion 22b and allowing it to harden. The filter frame 22 may hold a plurality of filters. The filter frame 22 has a filter frame side surface 22c on its side surface, and the filter frame side surface 22c engages with a lens holding portion side surface 141c of the fourth lens holder 141, which will be described later.

[0024] Moreover, the filter frame 22 has a gear portion 22d at an end. The gear portion 22d is engaged with a gear portion 23a of the filter driving portion 23. The filter driving portion 23 includes an actuator such as a stepping motor, and rotates the gear portion 23a. When the gear portion 23a is rotated by the filter driving portion 23, the filter frame 22 moves in a direction perpendicular to the optical axis. By moving the filter frame 22 in this manner, the filter 21 can be inserted into or removed from the optical path. Note that the driving method for inserting and removing the filter is not limited to this configuration. Also, the filter frame 22 is sandwiched between the fourth lens holder 141 and the sensor holder 31 in the optical axis direction. This restricts the movement of the filter frame 22 in the optical axis direction. Note that the method for restricting the movement direction of the filter frame 22 is not limited to this configuration.

[0025] The imaging unit 10 can obtain a desired image by forming an image of the collected light on the imaging element 35. The imaging unit 30 has a sensor holder 31, a second filter 32, a sensor rubber 33, a sensor plate 34, an imaging element 35, and an imaging board 36. The second filter 32 is a filter such as a low-pass filter. The sensor holder 31 has a second filter holding portion 31a (FIG. 7), and the second filter 32 abuts against the second filter holding portion 31a. The second filter 32 is pressed against the second filter holding portion 31a by the sensor rubber 33 and held therein.

[0026] The imaging element 35 is mounted on an imaging board 36. The imaging element 35 is adhesively fixed to an opening of a sensor plate 34. The sensor plate 34 is fixed to the sensor holder 31 with screws or the like. It is noted that the imaging unit 30 does not necessarily have to include the second filter 32 and the sensor rubber 33.

[0027] Moreover, the imaging element unit 30 does not have to have the sensor plate 34, and the imaging board 36 may be fixed to the sensor holder 31. Moreover, the imaging unit 30 does not have to have the sensor holder 31, and the imaging board 36 or the sensor plate 34 may be fixed to the fourth lens holder 141.

[0028] Next, the configuration of the fourth lens holder 141 and the configuration around the filter unit 20 will be described in detail.

[0029] The fourth lens holder 141 holds the fourth lens group 140. The fourth lens holder 141 has a lens holding portion 141a, an opening 141b, a lens holding portion side surface 141c, and a lens holding portion 141d. The lens holding portion 141a is in contact with the lens 140a of the fourth lens group 140 that is closest to the filter 21 in the optical axis direction. The lens holding portion 141a is partially molded at a position that does not overlap with an area through which the filter 21 and the filter holding portion 22a pass when inserted or removed as viewed from the optical axis direction.

[0030] A part of the filter holding portion 22a fits into the opening 141b. Therefore, when viewed from a direction perpendicular to the optical axis, the lens holding portion 141a of the fourth lens holder 141 and at least a part of the filter 21 overlap with each other.

[0031] In other words, at least a portion of the filter holding portion 22a is disposed in the opening 141b so as to overlap at least a portion of the fourth lens group 140 lens holder 141 when viewed from a direction perpendicular to the optical axis direction of the fourth lens group 140.

[0032] This allows the lenses 140a of the fourth lens holder 141 to be closer to the filter 21. This reduces the space in the optical axis direction required for inserting and removing the filter 21, shortens the back focus, and allows the imaging device to be made thinner.

[0033] The lens holder side surface 141c extends in a direction perpendicular to the optical axis. The lens holder side surface 141c abuts against a filter frame side surface 22c of the filter frame 22. In addition, the lens holder side surface 141c restricts movement of the filter frame 22 in the direction perpendicular to the optical axis.

[0034] The lens holding portion 141d clamps and fixes the fourth lens group 140 between itself and the lens holding portion 141a by thermal caulking.

[0035] In this embodiment, the lens holding portion 141a is partially molded, but the lens holding portion 141a may be molded around the entire circumference of the lens 140a. In that case, the lens holding portion 141a needs to be partially concave in the area through which the optical filter 21 and the optical filter holding portion 22a pass when they are inserted or removed, so as not to interfere with the optical filter 21 and the optical filter holding portion 22a.

[0036] 7, the filter frame 22 at least partially overlaps with the second filter holding portion 31a when viewed from a direction perpendicular to the optical axis. This configuration allows the filter 21 and the second filter 32 to be closer to each other. This reduces the space in the optical axis direction required for inserting and removing the filter 21, shortens the back focus, and allows the imaging device to be made thinner.

[0037] Next, insertion and removal of the filter 21 into and from the optical path will be described. When the gear portion 23a is rotated by the filter driving portion 23 from the state of FIG. 5, the filter frame 22 moves in a direction perpendicular to the optical axis. At this time, the filter frame side surface 22c of the filter frame 22 moves along the lens holding portion side surface 141c of the fourth lens holder 141 while engaged with the lens holding portion side surface 141c. Then, the filter is placed outside the optical path (FIG. 6). Conversely, when the gear portion 23a is rotated by the filter driving portion 23 from the state of FIG. 6, the filter frame 22 moves in a direction perpendicular to the optical axis. At this time, the filter frame side surface 22c of the filter frame 22 moves along the lens holding portion side surface 141c of the fourth lens holder 141 while engaged with the lens holding portion side surface 141c. Then, the filter is placed in the optical path (FIG. 5).

[0038] Moreover, the filter 21 is configured to be inserted and removed in the long side direction of the filter 21. With this configuration, the width of the area through which the filter 21 and the filter holding part 22a pass when being inserted and removed as viewed from the optical axis direction can be made smaller than that of a configuration in which the filter 21 is inserted and removed in the short side direction of the filter 21. This makes it easier to ensure a space for molding the lens holding part 141a.

[0039] According to the above-mentioned configuration, it is possible to provide an imaging device having a filter inserting / removing mechanism that can shorten the back focus.

[0040] <Embodiment 2> An imaging device according to a second embodiment of the present invention will be described below with reference to Fig. 8. Components common to the first embodiment are given the same reference numerals as in the first embodiment. Descriptions of configurations common to the first embodiment will be omitted. Fig. 8 is a cross-sectional view of the filter unit and its surroundings in the second embodiment. In the second embodiment, the position of the filter 21 relative to the filter frame 22 is different.

[0041] In this embodiment, the filter unit 20 is disposed at a position where the lens holding part 141a and the filter holding part 22a at least partially overlap when viewed from a direction perpendicular to the optical axis. Unlike the first embodiment, the lens holding part 141a and the filter 21 do not overlap when viewed from a direction perpendicular to the optical axis.

[0042] According to the above-mentioned configuration, it is possible to provide an imaging device having a filter inserting / removing mechanism that can shorten the back focus.

[0043] <Embodiment 3> An imaging device according to the third embodiment of the present invention will be described below with reference to Figs. 9 to 12. Components common to the first embodiment are given the same reference numerals as those in the first embodiment. Descriptions of configurations common to the first embodiment will be omitted. Fig. 9 is a perspective view of a fourth lens holder according to the third embodiment. Fig. 10 is a rear view of the filter unit and its surroundings when the filter according to the third embodiment is in the optical path. Fig. 11 is a rear view of the filter unit and its surroundings when the filter according to the third embodiment is out of the optical path. Fig. 12 is a cross-sectional view of the filter unit and its surroundings according to the third embodiment.

[0044] In the first embodiment, the filter frame side surface 22c of the filter frame 22 moves along the lens holding portion side surface 141c of the fourth lens holder 141, but in this embodiment, the filter frame 22 moves in the direction perpendicular to the optical axis following the guide of the guide pin 141e.

[0045] The lens 140a of the fourth lens group 140 that is closest to the filter 21 in the optical axis direction is in contact with the lens holding portion 141a. The fourth lens group 140 is fixed by being clamped between the lens holding portion 141d and the lens holding portion 141a by thermal caulking. The lens holding portion 141d of the fourth lens holder 141 is partially molded at a position that does not overlap with the area through which the filter 21 and the filter holding portion 22a pass when inserted and removed as viewed from the optical axis direction. Note that, although the lens holding portion 141d is partially molded in this embodiment, the lens holding portion 141d may be molded around the entire circumference of the lens 140a. In that case, the area through which the optical filter 21 and the optical filter holding portion 22a pass when inserted and removed needs to be partially concave in the lens holding portion 141d so as not to interfere with the optical filter 21 and the optical filter holding portion 22a. The lens holding portion 141d may be a separate member such as a pressing ring fixed to the lens holder 141.

[0046] The filter frame 22 has a guide hole 22e. The four-group lens holder 141 has a guide pin 141e. The guide pin 141e engages with the guide hole 22e extending in a direction perpendicular to the optical axis, so that the filter frame 22 can move in a direction perpendicular to the optical axis following the guide pin 141e. When the gear portion 23a is rotated by the filter driving portion 23, the filter frame 22 moves in a direction perpendicular to the optical axis following the guide of the guide pin 141e. By moving the filter frame 22 in this manner, the filter 21 can be inserted into or removed from the optical path. Note that the method of restricting the movement direction of the filter frame 22 is not limited to this configuration. Also, the driving method for inserting and removing the filter is not limited to this configuration.

[0047] In this embodiment, the filter unit 20 is disposed at a position where the lens holding portion 141d and the filter 21 at least partially overlap when viewed from a direction perpendicular to the optical axis. This allows the lens 140a and the filter 21 to be close to each other. This reduces the space in the optical axis direction required for inserting and removing the filter 21, shortens the back focus, and makes it possible to make the imaging device thinner. Note that, similarly to the second embodiment, the filter holding portion 22a and the filter holding portion 141d may be configured to overlap in the optical axis direction.

[0048] According to the above-mentioned configuration, it is possible to provide an imaging device having a filter inserting / removing mechanism that can shorten the back focus.

[0049] <Embodiment 4> An imaging device according to the fourth embodiment of the present invention will be described below with reference to Figs. 13 to 16. Components common to the first embodiment are given the same reference numerals as those in the first embodiment. Also, description of configurations common to the first embodiment will be omitted. Fig. 13 is a perspective view of a lens barrel according to the fourth embodiment. Fig. 14 is an exploded perspective view of the lens barrel according to the fourth embodiment. Fig. 15 is a front view of a fourth lens holder according to the fourth embodiment. Fig. 16 is a cross-sectional view of the filter unit and its surroundings according to the fourth embodiment. The fourth embodiment does not have a third lens group 130. Also, in the fourth embodiment, the fourth lens group 140 is movable in the optical axis direction.

[0050] Lens unit 10 has an imaging optical system including, in order from the subject side, a first lens group 110, a second lens group 120, and a fourth lens group 140. Fourth lens group 140 is held by a fourth lens holder 141. Fourth lens holder 141 engages with guide bar 153 and is supported so as to be movable in the optical axis direction of the imaging optical system. Fourth lens holder 141 also engages with guide bar 154, and rotation around guide bar 153 is restricted.

[0051] Furthermore, the fourth lens holder 141 holds a fourth group rack 142. The fourth group rack 142 engages with a lead screw portion of a fourth group drive unit 143 that includes an actuator such as a stepping motor. When the lead screw portion is rotated by the fourth group drive unit 143, the fourth lens holder 141 moves together with the fourth group rack 142 in the optical axis direction of the imaging optical system. The guide bars 151, 152, 153, and 154 are held by a front sleeve 150 and a rear sleeve 155.

[0052] The first lens group 110, the second lens group 120, and the fourth lens group 140 move in the optical axis direction of the imaging optical system in a predetermined positional relationship, thereby performing zooming and focusing of the imaging optical system.

[0053] When the fourth lens group 140 moves toward the imaging element side in the optical axis direction, the fourth lens group 140 and the filter 21 approach each other.

[0054] The lens holding portion 141a of the lens 140a is partially molded at a position that does not overlap with the area through which the filter 21 and the filter holding portion 22a pass when inserted and removed as viewed from the optical axis direction. This makes it possible to dispose the filter unit 20 at a position where at least a part of the lens holding portion 141a and the filter 21 overlap as viewed from a direction perpendicular to the optical axis. This makes it possible to bring the lens 140a and the filter 21 closer to each other, shortening the back focus and making it possible to make the imaging device thinner.

[0055] Note that the filter holding portion 22a and the filter holding portion 141d may be configured to overlap in the optical axis direction, similarly to the second embodiment. Also, the filter 21 or the filter holding portion 22a and the filter holding portion 141d may be configured to at least partially overlap in the optical axis direction, similarly to the third embodiment.

[0056] According to the above-mentioned configuration, it is possible to provide an imaging device having a filter inserting / removing mechanism that can shorten the back focus.

[0057] <Embodiment 5> An imaging device according to the fifth embodiment of the present invention will be described below with reference to Figs. 17 to 19. Components common to the first embodiment are given the same reference numerals as in the first embodiment. Also, description of configurations common to the first embodiment will be omitted. Fig. 17 is a perspective view of a filter frame according to the fifth embodiment. Fig. 18 is a perspective view of a second filter holder according to the fifth embodiment. Fig. 19 is a cross-sectional view of the filter unit and its surroundings according to the fifth embodiment. The configuration of the second filter holder in the fifth embodiment is different from that in the first embodiment.

[0058] The second filter holding portion 31a is partially formed. The filter holding portion 22a of the filter frame 22 has a recess 22f. The recess 22f is formed at a position overlapping with the second filter holding portion 31a when viewed from the optical axis direction.

[0059] The second filter holding portion 31 is disposed at a position where at least a portion of the filter holding portion 22a and the second filter holding portion 31a overlap in the optical axis direction when viewed from a direction perpendicular to the optical axis. Specifically, the filter frame 22 has a recess, and a portion of the second filter holding portion 31 is disposed in the recess. This allows the filter 21 and the second filter 32 to be closer to each other, thereby shortening the back focus and making the imaging device thinner.

[0060] Note that, similarly to the third embodiment, the filter 21 or the filter holding portion 22a may be configured to at least partially overlap with the filter holding portion 141d in the optical axis direction. Also, similarly to the fourth embodiment, the fourth lens group 140 may be configured to move in the optical axis direction of the imaging optical system.

[0061] According to the above-mentioned configuration, it is possible to provide an imaging device having a filter inserting / removing mechanism that can shorten the back focus.

[0062] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. Furthermore, the present invention is not limited to these embodiments as long as the configuration takes into consideration the design function. [Explanation of symbols]

[0063] 1 Lens barrel 10 Lens unit 20 Filter unit 21 Filters 21a Diagonal Length 22 Filter Pane 22c Filter frame side 23 Filter drive unit 30 Imaging unit 35 Image sensor 110 First lens group 120 Second lens group 130 Third lens group 140 4th lens group 140b Lens diameter 141 4th lens holder 141a Lens holder 141b opening 141c Lens holder side 141d Lens holder 150 Front Sleeve 151, 152, 153, 154 Guide bar O optical axis

Claims

1. a lens holder having an opening and configured to hold a lens; a filter holder that holds a filter in an optical path of the lens so that the filter can be inserted and removed; An imaging device, characterized in that at least a portion of the filter holder or at least one of the filter holders is positioned in the opening so as to overlap at least a portion of the lens holder when viewed from a direction perpendicular to the optical axis direction of the lens.

2. 2 . The imaging device according to claim 1 , wherein at least a portion of the filter holder is disposed in the opening so that at least a portion of the filter and the lens holder overlap when viewed from a direction perpendicular to the optical axis direction of the lens.

3. 2. The imaging device according to claim 1, wherein a diagonal length of the filter is shorter than a diameter of the lens.

4. The imaging device according to claim 1 , wherein the filter moves along a direction of a longer side of the filter.

5. 2. The imaging device according to claim 1, wherein a side surface of the lens holder engages with a side surface of the filter holder.

6. 2. The image pickup apparatus according to claim 1, wherein the lens holder has a guide pin, and the guide pin engages with a guide hole provided in the filter holder.

7. A second filter; A second filter holder for holding the second filter, 2 . The imaging device according to claim 1 , wherein the filter holder overlaps at least a portion of the second filter holder when viewed in a direction perpendicular to the optical axis direction of the lens.

Images