Lens device

Abstract

To provide a lens device that is less prone to surface distortion and other issues in its optical elements. [Solution] In a lens device comprising a main housing and a sub-housing fixed to the main housing, the sub-housing has one or more retaining members for holding optical elements, and at least one of the one or more retaining members includes a first adjustment part that can adjust the eccentric position relative to the main housing using a predetermined reference portion of the main housing.

Description

Technical Field

[0001] The present invention relates to a lens device having a sub-housing fixed to a main housing.

Background Art

[0002] Conventionally, for example, in zoom lenses used in broadcast television cameras and movie cameras for filming, with the recent high performance and high magnification, the lens barrel structure of zoom lenses has tended to become smaller and more compact.

[0003] The structure of a zoom lens includes an adjustment mechanism arranged to absorb errors from design values generated by the processing and assembly of components, so as to exhibit predetermined optical performance. Generally, its optical adjustment is performed using a plurality of lens groups.

[0004] That is, optical adjustment is performed by combining adjustments of a predetermined spatial interval within a fixed lens group or a moving lens group arranged at a specific position, parallel eccentricity adjustment, tilting adjustment, etc. of the fixed lens group or the moving lens group.

[0005] For example, Patent Document 1 discloses a structure in which a lens barrel fixed to a lens housing is fixed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, the prior art disclosed in Patent Document 1 mentioned above has a structure in which a different lens barrel is screw-fixed to a lens barrel fixed to a lens housing. As a result, the load from screw fixing causes distortion of the lens barrel fixed to the lens housing, which can cause surface distortion of optical elements and affect optical performance.

[0008] Furthermore, because the parallel eccentricity adjustment is performed with adjacent lens barrels temporarily fixed to the lens housing, the load from the parallel eccentricity adjustment can cause the lens barrels fixed to the lens housing to shift position, affecting the optical performance.

[0009] Therefore, one of the objectives of the present invention is to provide a lens device that is less prone to surface distortion and the like in optical elements. [Means for solving the problem]

[0010] To achieve the above objective, an embodiment of the present invention provides a lens device comprising a main housing and a sub-housing fixed to the main housing, wherein the sub-housing has one or more holding members for holding optical elements, and at least one of the one or more holding members includes a first adjustment part that can adjust the eccentric position relative to the main housing using a predetermined reference portion of the main housing. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a lens device that is less prone to surface distortion and the like in the optical elements. [Brief explanation of the drawing]

[0012] [Figure 1] This is a cross-sectional view XX of the focus section of the lens device 1 according to Embodiment 1. [Figure 2] This is a front view of the lens device 1 according to Embodiment 1. [Figure 3] This is a side view of the lens device 1 according to Embodiment 1. [Figure 4]This is a cross-sectional view showing the sub-casing 6 fixed to the main casing 2 according to Embodiment 1. [Figure 5] This is a cross-sectional view showing the lens barrel 8 fixed to the sub-casing 6 according to Embodiment 1. [Figure 6] This is a cross-sectional view of the focusing section of the lens device 1 according to Embodiment 2. [Figure 7] This is a front view of the lens device 1 according to Embodiment 2 with the lens barrel 7 removed. [Figure 8] This is an enlarged YY cross-sectional view of the through-hole 6a in the main housing 2 according to Embodiment 2, where the sub-housing 6 and lens barrel 8 are fixed. [Figure 9] This is an enlarged YY cross-sectional view of the 12 positioning collars in the state where the sub-casing 6 is fixed to the main casing 2 according to Embodiment 2. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following embodiments. In each drawing, the same reference numeral is used for the same member or element, and redundant explanations are omitted or simplified.

[0014] <Embodiment 1> Hereinafter, a lens device according to Embodiment 1 of the present invention will be described with reference to Figures 1 to 5. Figure 1 is a cross-sectional view of the focus section XX of the lens device 1 according to Embodiment 1, Figure 2 is a front view of the lens device 1 according to Embodiment 1, and Figure 3 is a side view of the lens device 1 according to Embodiment 1. Figure 4 is a cross-sectional view of the state in which the sub-housing 6 is fixed to the main housing 2 according to Embodiment 1, and Figure 5 is a cross-sectional view of the state in which the lens barrel 8 is fixed to the sub-housing 6 according to Embodiment 1.

[0015] In this embodiment, the lens device 1 includes a main housing 2 and a sub-housing 6 fixed to the main housing 2. Further, the outer diameter of the object side of the main housing 2 held by the lens device 1 is larger than the outer diameter of the image plane side of the main housing, and the sub-housing 6 is fixed to the end face of the object side of the main housing 2. Further, a focus cam ring 4 connected by a focus operation ring 3 and a roller member (not shown) is provided.

[0016] Thus, in this embodiment, the focus cam ring 4 as a rotation operation unit for driving a holding member (lens holder) held movably in the optical axis direction with respect to the main housing 2 among one or more holding members is arranged. Note that the rotation operation unit is arranged in a space between the outermost diameter of the main housing 2 and a part of the outer diameter of the sub-housing 6.

[0017] Here, as shown in FIG. 3, the object side represents the direction of the subject side (arrow B direction) when shooting using the lens device and the imaging camera, and the imaging plane side represents the direction of the camera side (arrow C direction). The focus cam ring 4 is arranged to have substantially the same diameter as the outer diameter of the image plane side of the main housing 2.

[0018] The optical moving group 5 is held slidably with respect to the main housing 2 in the optical axis A direction, and is connected to a cam lift 4a of the focus cam ring 4 by a cam roller (not shown). In this state, when the focus operation ring 3 is rotated, the focus cam ring 4 rotates according to the rotation angle of the focus operation ring 3, and the optical moving group 5 moves in the optical axis A direction along a locus along the cam lift 4a to perform focus adjustment.

[0019] The sub-housing 6 is fixed to the end face of the object side of the main housing 2, and holds the lens barrel 7 and the lens barrel 8 in a state where they can be eccentric in a plane direction perpendicular to the optical axis A. Here, the lens barrel 7 is a lens barrel that performs eccentricity adjustment so that the lens device 1 can exhibit predetermined optical performance, and the lens barrel 8 is a lens barrel that adjusts the eccentric position with respect to the main housing 2.

[0020] Furthermore, the lens barrel 7 and lens barrel 8 each function as retaining members for holding optical elements, and the sub-housing 6 of this embodiment has one or more retaining members for holding optical elements. Note that the optical elements are not limited to lenses, but may also include filters, apertures, etc. Also, the retaining members in this embodiment can be called, for example, lens holders.

[0021] The lens barrels 7 and 8 are fixed separately to the sub-housing 6, making it difficult to transmit the load from tightening the screws that secure the lens barrel 7 to the lens barrel 8. As a result, even if the eccentricity of the lens barrel 7 is adjusted, the lens barrel 8 does not move along with it. Therefore, deformation caused by the load on the lens barrel 8 during assembly is less likely to be transmitted to the optical elements, thus suppressing the impact on optical performance during assembly.

[0022] The fixing radius R1 of the fixing screw 9 of the sub-casing 6, the fixing radius R2 of the fixing screw 10 of the lens barrel 7, and the fixing radius R3 of the fixing screw 11 of the lens barrel 8 are arranged such that the difference in diameter is in the order R1 > R2 > R3.

[0023] Therefore, it is possible to remove the sub-casing 6 from the main casing 2 while holding the lens barrels 7 and 8, improving ease of assembly when cleaning the inside of the main casing 2 during assembly.

[0024] The positioning collar 12, which serves as the first adjustment part, is fixed to the sub-housing 6 with screws after its mounting position is adjusted using the outer diameter R4 of the main housing 2, which serves as the second adjustment part, as the reference diameter, and the lens barrel 8 is fixed to the sub-housing 6 with the position of the positioning collar 12 as the reference.

[0025] Thus, in this embodiment, at least one of the one or more retaining members includes a first adjustment unit that can adjust the eccentric position relative to the main housing 2 using a predetermined reference portion of the main housing 2.

[0026] By fixing the lens barrel 8 in this procedure, the effects of mounting play between the sub-casing 6 and the main casing 2 are suppressed, and the lens barrel 8 can be fixed to the main casing 2 with precision. The structure is not limited to the above; after adjusting the eccentric position of the lens barrel 8 relative to the main casing 2, it is also acceptable to fix it to the sub-casing 6.

[0027] For example, the outer diameter R4 of the main housing 2, which serves as the second adjustment part, may be used as the reference diameter, and the lens barrel 8 may be fixed after being adjusted so that its outer diameter R5 is coaxial with the outer diameter R4, which serves as the first adjustment part. In other words, the outer diameter of the object-side end face of the main housing 2 may be used as the reference part provided on the main housing 2.

[0028] By fixing the lens barrel 8 based on the position of the main housing 2, which holds other optical elements, rather than fixing it based on the position of the sub-housing 6, variations in optical performance due to the increase in parts caused by separating the main housing 2 and the sub-housing 6 can be suppressed.

[0029] In other words, according to the lens device of this embodiment, after optical adjustment is performed by adjusting the parallel eccentricity of the lens barrel, even if multiple lens barrels are fixed together with screws, for example, surface distortion and the like are less likely to occur in the optical elements, thus minimizing the impact on optical performance.

[0030] Furthermore, the eccentricity sensitivity of the lens barrel 7 held in the sub-housing 6 and the eccentricity sensitivity of the lens barrel 8 may be similar in magnitude but with opposite signs. Here, eccentricity sensitivity represents the ratio of the amount of movement of the lens barrel to the amount of change in aberrations such as coma when the lens barrel is eccentric in a direction perpendicular to the optical axis A. The sign of eccentricity sensitivity indicates, in positive or negative terms, the direction of movement of the lens barrel and the direction of change in aberrations such as coma when the lens barrel is eccentric in a direction perpendicular to the optical axis A and in a predetermined direction.

[0031] In this case, the sum of the eccentricity sensitivities of the lens barrel 7 and lens barrel 8 held by the sub-housing 6 is smaller than the individual eccentricity sensitivities of each, making it possible to suppress the impact on optical performance even if the sub-housing 6 is eccentric due to an external force.

[0032] In this embodiment, the sub-housing 6 is configured to hold two lens barrels, but this is not the only requirement; it is sufficient that the sum of the eccentricity sensitivities of multiple lens barrels is smaller than the eccentricity sensitivities of each individual lens barrel. In other words, in this embodiment, the sum of the eccentricity sensitivities of the multiple holding members held by the sub-housing 6 is smaller than the eccentricity sensitivities of each individual holding member held by the sub-housing 6.

[0033] The outer ring 13 is fixed to the sub-casing 6 with screws, and the support column 14 is provided on the outside of the outer ring 13 and is fixed to the sub-casing 6 with screws. The support column 14 is used to connect to a guide bar installed below the camera in order to stably hold the lens device 1 when mounting the photographic equipment on a tripod. In other words, the sub-casing 6 has a support column 14 as a support member for connecting the lens device to the camera photographic device, and the support column 14 is fixed to the sub-casing 6.

[0034] In this embodiment, the effects of an external force being applied to the lens device 1 while it is fixed to the camera will be explained. The support column 14 provided in the lens device 1 is fixed to the sub-housing 6, and an external force is transmitted to the sub-housing 6, which may cause it to become eccentric from its initial assembly position.

[0035] In this case, since lens barrels 7 and 8, which have opposite signs of eccentricity sensitivity and are of similar size, are fixed to the sub-housing 6, even if the sub-housing 6 becomes eccentric, lens barrels 7 and 8 will become eccentric by the same proportion, thus making it possible to suppress the effects of changes in optical performance.

[0036] In this embodiment, the influence of changes in optical performance is suppressed by ensuring that the sign of the eccentricity sensitivity of one holding member held in the sub-housing is different from the sign of the eccentricity sensitivity of the other holding members.

[0037] <Embodiment 2> The lens device according to Embodiment 2 of the present invention will now be described with reference to Figures 6 to 9. Figure 6 is a cross-sectional view of the focusing section of the lens device 1 according to Embodiment 2, and Figure 7 is a front view of the lens device 1 according to Embodiment 2 with the lens barrel 7 removed.

[0038] Figure 8 is an enlarged YY cross-sectional view of the through-hole 6a in the state in which the sub-housing 6 and lens barrel 8 are fixed to the main housing 2 according to Embodiment 2. Figure 9 is an enlarged YY cross-sectional view of the positioning collar 12 locations in the state in which the sub-housing 6 is fixed to the main housing 2 according to Embodiment 2.

[0039] In Embodiment 1, the outer diameter of the main housing 2 on the object side is larger than the outer diameter of the main housing 2 on the image plane side. However, in Embodiment 2, the outer diameter of the main housing 2 on the object side is smaller than the outer diameter of the main housing 2 on the image plane side, and the sub-housing 6 is fixed to the end face of the main housing 2 on the object side.

[0040] The fixing radius R1 of the fixing screw 9 of the sub-housing 6 and the fixing radius R2 of the fixing screw 10 of the lens barrel 7 are arranged such that the diameter difference is R2 > R1, and the focus cam ring 4 is positioned to have approximately the same diameter as the outer diameter of the object side of the main housing 2.

[0041] Therefore, the focus cam ring 4 is held in the space between the main housing 2 and the sub-housing 6, enabling miniaturization of the lens device 1.

[0042] The main housing 2 is provided with two reference holes 2a, which serve as second adjustment parts for adjusting the fixed position of the lens barrel 8. Furthermore, when the lens barrel 8 is fixed to the sub-housing 6, an adjustment hole 8a, which has the same diameter as the reference holes 2a, is provided in the main housing 2 at a position opposite to the reference holes 2a, serving as a first adjustment part. Here, the reference holes 2a function as predetermined reference points when adjusting the eccentric position relative to the main housing 2 by the first adjustment part.

[0043] Furthermore, the sub-housing 6 is provided with a through-hole 6a that is larger in diameter than the reference hole 2a and is in the same phase as the reference hole 2a when it is fixed to the main housing 2. With this structure, a pin tool with approximately the same diameter as the reference hole 2a and the adjustment hole 8a of the lens barrel 8 is inserted into the reference hole 2a of the main housing 2 and the adjustment hole 8a of the lens barrel 8, and the lens barrel 8 is fixed to the sub-housing 6.

[0044] Thus, in this embodiment, the first adjustment portion provided in the lens barrel 8, which serves as a retaining member, is a hole with two or more holes, and the reference portion provided in the main housing is a reference hole 2a located opposite the first adjustment portion and having the same diameter as the first adjustment portion.

[0045] By fixing the lens barrel 8 in this procedure, the effects of mounting play between the sub-casing 6 and the main casing 2 are suppressed, and the lens barrel 8 can be fixed to the main casing 2 with precision. The structure is not limited to the above; after adjusting the eccentric position of the lens barrel 8 relative to the main casing 2, it is also acceptable to fix it to the sub-casing 6.

[0046] For example, the inner diameter R6 of the main housing 2 may be used as the reference diameter for the second adjustment part, and the fixing position of the positioning collar 12 may be adjusted as the first adjustment part, after which the lens barrel 8 may be fixed to the position of the positioning collar 12. Thus, in this embodiment, the predetermined reference part is the outer or inner diameter of the object-side end face of the main housing 2.

[0047] Although the present invention has been described in detail above based on its preferred embodiments, the present invention is not limited to the above embodiments, and various modifications and combinations of the above embodiments are possible in accordance with the spirit of the present invention, and these are not excluded from the scope of the present invention. Furthermore, some of the above embodiments may be combined as appropriate.

[0048] (Configuration 1) A lens device comprising a main housing and a sub-housing fixed to the main housing, wherein the sub-housing holds one or more holding members for holding optical elements, and at least one of the one or more holding members includes a first adjustment part that can adjust the eccentric position relative to the main housing using a predetermined reference portion of the main housing.

[0049] (Configuration 2) The lens device according to Configuration 1, characterized in that the outer diameter of the main housing on the object side is smaller than the outer diameter of the main housing on the image plane side, and the sub-housing is fixed to the end face of the main housing on the object side.

[0050] (Configuration 3) The lens device according to Configuration 1, characterized in that the outer diameter of the main housing on the object side is larger than the outer diameter of the main housing on the image plane side, and the sub-housing is fixed to the end face of the main housing on the object side.

[0051] (Configuration 4) A lens device according to any one of Configurations 1 to 3, wherein the device has a rotating operating unit that drives one or more holding members that are held so as to be movable in the optical axis direction relative to the main housing, and the rotating operating unit is arranged in the space between the outermost diameter of the main housing and the outer diameter of a part of the sub-housing.

[0052] (Configuration 5) The lens device according to any one of Configurations 1 to 4, characterized in that the predetermined reference portion is the outer diameter or inner diameter of the end face on the object side of the main housing.

[0053] (Configuration 6) The lens device according to any one of Configurations 1 to 5, characterized in that the first adjustment section has two or more holes, and the reference section provided in the main housing is positioned opposite the first adjustment section and is a reference hole provided at a position with the same diameter as the first adjustment section.

[0054] (Configuration 7) The lens device has a support member for connecting it to the camera shooting device, The lens device according to any one of configurations 1 to 6, characterized in that the support column member is fixed to the sub-housing.

[0055] (Configuration 8) The lens device according to any one of Configurations 1 to 7, characterized in that the sum of the eccentricity sensitivity of the plurality of holding members held in the sub-housing is smaller than the eccentricity sensitivity of each of the holding members held in the sub-housing.

[0056] (Configuration 9) The lens device according to any one of Configurations 1 to 8, characterized in that the sign of the eccentricity sensitivity of one holding member held in the sub-housing and the sign of the eccentricity sensitivity of the other holding member are different from each other. [Explanation of Symbols]

[0057] 1: Lens device 2: Main cabinet 2a: Reference hole 3: Focus control ring 4: Focus cam ring 4a: Cam lift 5: Optical moving group 6: Sub-cabinet 6a: Through hole 7: Lens barrel 8: Lens barrel 8a: Adjustment hole 9: Fixing screws for sub-casing 6 10: Fixing screws for lens barrel 7 11: Fixing screws for lens barrel 8 12: Positioning color 13:Exterior ring 14:Support strut A: Optical axis R1: Fixing radius of fixing screw 9 R2: Fixing radius of fixing screw 10 R3: Fixing radius of fixing screw 11 R4: Outer diameter of the main chassis R5: Outer diameter of lens barrel 8 R6: Inner diameter of the main enclosure

Claims

1. In a lens device comprising a main housing and a sub-housing fixed to the main housing, The sub-housing has one or more holding members for holding optical elements, A lens device characterized in that at least one of the one or more retaining members includes a first adjustment part that can adjust the eccentric position relative to the main housing using a predetermined reference portion of the main housing.

2. The outer diameter of the main housing on the object side is smaller than the outer diameter of the main housing on the image plane side. The lens device according to claim 1, characterized in that the sub-housing is fixed to the object-side end face of the main housing.

3. The outer diameter of the main housing on the object side is larger than the outer diameter of the main housing on the image plane side. The lens device according to claim 1, characterized in that the sub-housing is fixed to the object-side end face of the main housing.

4. The system includes a rotating operation unit for driving one or more of the holding members that are held so as to be movable in the optical axis direction relative to the main housing, The lens device according to claim 1, characterized in that the rotating operating part is arranged in the space between the outermost diameter of the main housing and the outer diameter of a part of the sub-housing.

5. The lens device according to claim 1, characterized in that the predetermined reference portion is the outer diameter or inner diameter of the end face on the object side of the main housing.

6. The first adjustment section has two or more holes, The lens device according to claim 1, characterized in that the reference portion provided in the main housing is positioned opposite to the first adjustment portion and is a reference hole provided at a position having the same diameter as the first adjustment portion.

7. The lens device has a support member for connecting it to the camera shooting device, The lens device according to claim 1, characterized in that the support member is fixed to the sub-casing.

8. The lens device according to claim 1, characterized in that the sum of the eccentricity sensitivity of the plurality of holding members held in the sub-housing is smaller than the eccentricity sensitivity of each of the holding members held in the sub-housing.

9. The lens device according to claim 1, characterized in that the sign of the eccentricity sensitivity of one holding member held in the sub-housing and the sign of the eccentricity sensitivity of the other holding member are different from each other.

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