Lens barrel

Abstract

To provide a lens barrel which enables both alignment work for shift alignment and tilt alignment and lens spacing adjustment work, and offers superior workability in the alignment work and adjustment work and a minimized increase in outer diameter thereof by devising an arrangement.SOLUTION: A lens barrel is provided, comprising a lens holding member for holding lenses, a base member for fixing the lens holding member, and an adjustment member for adjusting a positional relationship between the lens holding member and the base member, where the adjustment member comprises a first adjustment part that enables adjustment in a direction perpendicular to an optical axis of the lenses, and a second adjustment part that enables adjustment in a direction along the optical axis.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a lens barrel having an alignment mechanism for adjusting optical performance, which is composed of a plurality of lenses.

Background Art

[0002] In recent years, imaging devices have been required to have higher performance and smaller size. As an example, an imaging device has come to adopt an imaging element that can obtain a higher-resolution image. As a result, the optical performance required for a lens barrel used in combination with such an imaging element has also become higher in accordance with the performance of the imaging element.

[0003] A lens barrel has a plurality of lens chambers each composed of one or more lenses. When assembling such a lens barrel, simply assembling the lens chambers into the lens barrel cannot obtain the optical performance as designed. This is because errors occur during the manufacture of each member constituting the lens barrel such as the lens chamber, resulting in a deviation in the positional relationship between the lens chambers, and as a result, it has an adverse effect on resolution.

[0004] Therefore, in the manufacturing process of the lens barrel, an adjustment process is provided to suppress a decrease in optical performance due to manufacturing errors of the lens barrel.

[0005]

[0006] Patent Document 1 discloses a lens barrel that performs shift alignment for moving a lens on a plane perpendicular to the optical axis and tilt alignment for moving a plane perpendicular to the optical axis to the object side or the image side.

Prior Art Documents

Patent Documents

[0007] [Patent Document 1] Patent No. 4817876 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, the lens barrel described in Patent Document 1 has the problem that it is not possible to adjust the lens spacing, which adjusts the distance between lenses in the lens group or within the lens group, along with shift and tilt adjustment.

[0009] This invention has been made in view of the above circumstances, and aims to provide a lens barrel that achieves both shift and tilt alignment work and lens spacing adjustment work simultaneously, and by devising the arrangement, offers excellent workability in alignment and adjustment work, while suppressing an increase in the outer diameter of the product. [Means for solving the problem]

[0010] The first invention, which is a means for solving the above problem, is a lens barrel having a lens holding member for holding a lens, a base member for fixing the lens holding member, and an adjustment member for adjusting the positional relationship between the lens holding member and the base member, wherein the adjustment member has a first adjustment part that can be adjusted in a direction perpendicular to the optical axis of the lens, a second adjustment part that can be adjusted in a direction along the optical axis, and a spacer shaft consisting of a screw and a spacer for fixing the second adjustment part to the base member, the first adjustment part is an eccentric roller, the second adjustment part is an adjustment washer, and the lens holding member is the Spacer The spacer shaft engagement portion has an insertion hole through which the spacer is inserted, and the insertion hole is the Spacer of constricted area The lens barrel is characterized by being formed larger, so that even when the second adjustment part is fixed to the base member, the lens holding member can be adjusted in position relative to the base member. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a lens barrel that achieves both shift and tilt alignment work and lens spacing adjustment work simultaneously, and by devising the arrangement, offers excellent workability in alignment and adjustment work, while suppressing an increase in the outer diameter of the product. [Brief explanation of the drawing]

[0012] [Figure 1] A perspective view showing the main part of the lens barrel adjustment mechanism according to an embodiment of the present invention. [Figure 2] Exploded perspective view of the lens barrel adjustment mechanism according to an embodiment of the present invention [Figure 3] Cross-sectional perspective view of the first lens group of a lens barrel according to an embodiment of the present invention. [Modes for carrying out the invention]

[0013] The best mode for carrying out the present invention will be described below with reference to the attached drawings. However, the present invention is not limited to this embodiment.

[0014] Figure 1 is a perspective view showing the main part of a lens barrel according to one embodiment of the present invention. Note that Figure 1 is simplified to show only the main part of the adjustment mechanism in order to explain the adjustment process for shift alignment, tilt alignment, and lens spacing adjustment of the lens barrel of the present invention. Figure 2 is an exploded perspective view showing an enlarged view of the area around the adjustment mechanism in Figure 1. Figure 3 is a cross-sectional perspective view of the first lens group of the lens barrel. In this embodiment, the direction along the optical axis of the lens barrel, that is, the optical axis of the first lens group constituting the lens barrel, is defined as the thrust direction, and the direction perpendicular to the optical axis is defined as the radial direction. Furthermore, in all drawings, the left side in the thrust direction is the object side, the right side is the image side, the radial direction optical axis side is the inner circumference, and the opposite side is the outer circumference.

[0015] As shown in each drawing, the lens barrel of the present invention has an adjustment mechanism which is an adjustment member, and the adjustment mechanism comprises a fitting portion 111 of the base member 110, a spacer shaft engaging portion 122 of the lens chamber 120, an eccentric roller 130, an adjustment washer 140, and a spacer shaft 150. The base member 110 and the lens chamber 120 correspond to the first lens group, which is located closest to the object among the lens groups that constitute the lens barrel. Therefore, in the lens barrel of the present embodiment, the first lens group is an adjustment group that is subject to adjustment for shift alignment, tilt alignment, and lens spacing adjustment. In addition, a front ring is arranged on the radial outer diameter side of the first lens group, a name ring or light-shielding member is arranged on the thrust direction object side, and the second and third lens groups and a mount connected to the imaging device are arranged on the thrust direction image side.

[0016] Furthermore, the configuration of the first lens group will be explained in detail. In addition to the lens held by the lens chamber 120, the first lens group has a second lens and a third lens (not shown) on the image side in the thrust direction.

[0017] The base member 110 is a fixed cylinder that constitutes the lens barrel. It is fixed to the front ring with a screw (not shown) in the screw hole 112 located in the lower right of Figure 1. In this embodiment, it is a fixed cylinder, but it is also possible to form a cam groove in the base member 110 and make the base member 110 a straight cylinder that moves along the optical axis. The base member 110 also has a fitting portion 111 which is an elongated hole for fitting the eccentric roller 130.

[0018] The lens chamber 120 is a component that holds glass material (not shown) and corresponds to a lens holding component. Tilt alignment is performed by adjusting the degree to which the lens chamber 120 is tilted relative to the optical axis. Shift alignment is performed by moving the lens chamber 120 on a plane perpendicular to the optical axis. The lens chamber 120 is also provided with a fitting hole 121 into which an eccentric roller 130, which is fitted into a fitting portion 111 of the base member 110, is fitted. Furthermore, the spacer shaft 150 Insertion A spacer shaft engagement portion 122 is provided. The spacer shaft engagement portion 122 has a concave shape with the radial outer circumference side open.

[0019] The eccentric roller 130 fits into the fitting portion 111 of the base member 110 and also fits into the fitting hole 121 of the lens mirror chamber 120. By rotating the eccentric roller 130 with an adjustment jig, the lens mirror chamber 120 moves on a plane perpendicular to the optical axis, thereby performing shift alignment.

[0020] The adjustment washer 140 is positioned between the spacer shaft engaging portion 122 of the lens mirror chamber 120 and the base member 110, and is fixed to the base member 110 together with the lens mirror chamber 120 by the spacer shaft 150. By changing the number and thickness of the adjustment washers 140, the positional relationship in the direction along the optical axis between the lens mirror chamber 120 and the base member 110 is changed. That is, the lens interval can be adjusted. Also, the adjustment washer 140 has a shape with an open through-hole. As a result, the adjustment washer 140 can be inserted and removed from the radial outer peripheral side to the screw portion of the spacer shaft 150 with an adjustment jig. In this embodiment, it is a washer, but as long as it has the function of maintaining the distance between the base member 110 and the lens mirror chamber 120 and has an insertable and removable shape, a spacer or the like is also acceptable.

[0021] The spacer shaft 150 is composed of a screw and a spacer. The spacer engages with the spacer shaft engaging portion 122 of the lens mirror chamber 120, and by fixing the spacer shaft 150 to the base member 110, the positional relationship in the thrust direction between the base member 110 and the lens mirror chamber 120 is fixed. Specifically, the spacer shaft 150 in FIG. 2 is fixed by fitting into a hole on the base member 110 at the tip of the dotted line extending from the tip of the screw.

[0022] FIG. 2 is an enlarged exploded perspective view of the vicinity of the adjustment mechanism of the lens barrel of the present invention. The adjustment process will be described using FIG. 2.

[0023] In the adjustment process, the lens barrel is mounted on an adjustment jig such as an MTF measuring instrument, and the adjustment group is adjusted while observing the resolution performance of the image formed by the light passing through the lens barrel. In the lens barrel of the present invention, the lens barrel achieves optical performance according to the design value by performing tilt adjustment, shift adjustment, and lens spacing adjustment on the glass material (not shown) held in the lens chamber 120 during the adjustment process.

[0024] To perform tilt alignment, the number and thickness of the adjustment washers 140, which are inserted between the base member 110 and the three spacer shaft engagement portions 122 located on the outer circumference of the lens chamber 120, are changed. By changing the number and thickness of the adjustment washers 140, the tilt of the glass material held in the lens chamber relative to the optical axis can be adjusted, thereby enabling tilt alignment.

[0025] Furthermore, by similarly adjusting the adjustment washers 140 inserted between all the spacer shaft engagement portions 122 on the outer circumference and the base member 110, it becomes possible to adjust the distance between the base member 110 and the lens chamber 120. In other words, since the glass material can be moved in the thrust direction without changing its inclination with respect to the optical axis, it becomes possible to adjust the spacing of the lenses, which are made of glass material.

[0026] Finally, to perform shift alignment, the eccentric roller 130, which fits into the fitting portion 111 and the fitting hole 121, is rotated using an adjustment jig. This causes the eccentric roller 130 to move the lens chamber 120 on a plane perpendicular to the optical axis via the fitting hole 121. By adjusting each of the three eccentric rollers 130 located on the outer circumference, the lens glass material held in the lens chamber 120 can also be moved on a plane perpendicular to the optical axis. In other words, shift alignment of the glass material becomes possible. After adjustment, the radial positional relationship between the base member 110 and the lens chamber 120 is fixed.

[0027] As mentioned above, the adjustment process using an MTF measuring instrument is generally performed while observing the resolution performance. Therefore, it is desirable that the jig can be inserted from the radial direction when rotating the eccentric roller 130 and inserting / removing the adjustment washer 140 for adjusting the centering and spacing. By allowing the jig to be inserted from the radial direction, the jig can be operated without interfering with the observation of resolution performance, and thus the present invention has excellent workability.

[0028] Furthermore, since adjustment is possible by inserting a jig from the radial direction, it becomes possible to have a lens barrel configuration as shown in Figure 3, which has a second and third lens that can be further adjusted within the first lens group, which is the adjustment group shown in Figures 1 and 2. A detailed explanation will be given below using Figure 3.

[0029] Although only one second adjustment mechanism for adjusting the second lens chamber 220 and the third lens chamber 320 is shown in Figure 3, it goes without saying that, like the adjustment mechanism for adjusting the first lens chamber, these second adjustment mechanisms are arranged at 120° intervals around the outer circumference of the lens chamber to be adjusted.

[0030] Figure 3 is a cross-sectional perspective view of the first lens group of the lens barrel of the present invention, cut in the thrust direction. As described above, the first lens group has a second lens and a third lens, and the second lens chamber 220 and the third lens chamber 320 hold their respective glass materials. The lens chamber 120 also has a second fitting portion 123 which has an elongated hole shape similar to the fitting portion 111, and the eccentric roller 230, adjustment washer 240, and spacer shaft 250 perform the same roles as the eccentric roller 130, adjustment washer 140, and spacer shaft 150, respectively. The adjustment members for adjusting these second and third lenses constitute the second adjustment mechanism.

[0031] The relationship between each lens chamber will now be explained. Similar to the engagement relationship between the spacer shaft 150 and the spacer shaft engagement portion 122, the spacer portion of the spacer shaft 250 engages with the third lens chamber 320, and the spacer shaft 250 is fixed to the second lens chamber 220. Furthermore, since the adjustment washer 240 is located between the second lens chamber 220 and the third lens chamber 320, the distance between the second and third lenses and the tilt alignment of the third lens can be adjusted by adjusting the number and thickness of the adjustment washer 240, and the third lens chamber 320 is fixed to the second lens chamber 220. Next, the eccentric roller 230 fits into the second fitting portion 123 of the lens chamber 120 and fits into the second lens chamber 220. In other words, the lens chamber 120 holds the second lens chamber 220, and by rotating the eccentric roller 230 with an adjustment jig, the second lens chamber 220 moves on a plane perpendicular to the optical axis. Therefore, the second lens can be shift-aligned.

[0032] Furthermore, the fitting portion 111 shown in Figure 2 and the second fitting portion 123 shown in Figure 3 have an elongated hole shape in the thrust direction, and the length of this elongated hole is the sum of the eccentricity of the eccentric roller and the maximum thickness of the adjustment washer that is expected to be inserted when performing shift alignment and lens spacing adjustment.

[0033] From the above, the lens barrel shown in Figure 3 allows for centering adjustment between the first and third lenses of the first lens group by enabling shift centering of the second lens, tilt centering of the third lens, and adjustment of the distance between the second and third lenses. Next, by performing the adjustment process on the first lens of the centered first lens group as explained using Figure 2, the lens barrel can obtain optical performance as designed.

[0034] Furthermore, the adjustment mechanism of the present invention is arranged at three locations on the outer circumference of the base member 110 at 120° intervals. The fitting portion 111 of the base member 110, the spacer shaft engagement portion 122 of the lens chamber 120, the eccentric roller 130, the adjustment washer 140, and the spacer shaft 150, which are adjustment mechanisms for shift alignment, tilt alignment, and spacing adjustment, are all arranged together on the outer circumference of the base member 110. Similarly, the second adjustment mechanism is also arranged together on the outer circumference of the second lens chamber 220 and the third lens chamber 320, which makes it possible to suppress the increase in the outer diameter of the product on the radial outer side of the base member 110.

[0035] Next, since the adjustment mechanisms for adjusting the first lens are arranged at 120° intervals on the outer circumference of the base member 110, as shown in Figure 3, the second adjustment mechanism for adjusting the second and third lenses is positioned with a phase difference from the adjustment mechanism for adjusting the first lens group. By forming grooves in the base member 110 at the corresponding locations to allow the adjustment jig to access the second adjustment mechanism from the radial direction, the lens barrel can have two adjustment mechanisms. As a result, as mentioned above, it becomes possible to perform more precise centering adjustments and lens spacing adjustments, enabling the manufacture of lens barrels with superior optical performance.

[0036] Furthermore, it is desirable that the eccentric rollers and adjustment washers within each adjustment mechanism be arranged in a series so that they are adjacent to each other. This reduces the amount of movement during adjustment, resulting in excellent workability, and because the base member 110 is located on the outer circumference side, as in the second adjustment mechanism, it becomes possible to reduce the size of the groove when providing a groove for inserting a jig. [Explanation of symbols]

[0037] 110 Fixed tube 111 Fitting part 112 screw holes 120 Lens chamber 121 Fitting hole 122 Spacer shaft engagement part 123 Second fitting section 130 Eccentric Roller 140 Adjustment Washer 150 Spacer shaft 220 Second Lens Chamber 230 eccentric roller 240 Adjustment Washer 250 Spacer shaft 320 Third Lens Chamber

Claims

1. A lens holding member that holds the lens, A base member for fixing the lens holding member, An adjustment member for adjusting the positional relationship between the lens holding member and the base member, A lens barrel having, The aforementioned adjustment member is A first adjustment unit that can be adjusted in a direction perpendicular to the optical axis of the lens, A second adjustment unit that can be adjusted in a direction along the optical axis, The second adjustment part is fixed to the base member by a spacer shaft consisting of a screw and a spacer, It has, The first adjustment part is an eccentric roller, The second adjustment part is an adjustment washer, The lens holding member is The spacer shaft engagement portion has an insertion hole through which the spacer is inserted, The lens barrel is characterized in that the insertion hole is formed to be larger than the constricted portion of the spacer, so that even when the second adjustment part is fixed to the base member, the position of the lens holding member can be adjusted relative to the base member.

2. The aforementioned adjustment member is The lens barrel according to claim 1, characterized in that at least three locations are provided on the outer circumference of the base member.

3. The lens barrel according to claim 1 or 2, characterized in that a jig can be inserted from a direction perpendicular to the optical axis when adjusting the first adjustment section and the second adjustment section.

4. The base member is Having a fitting portion through which the eccentric roller is inserted, The lens barrel according to claim 1, characterized in that the fitting portion has an elongated hole shape that combines the eccentricity of the eccentric roller and the amount of the adjustment washer.

Images