JP2012113020A - Adjusting structure and adjusting device of photographing lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photographing lens for easily and steplessly adjusting an interval of two adjoining lenses from the outside without disassembling the lenses while confirming the optical performances, causing no change in the optical performances from the outside of the lenses after the adjustment, and having favorable assembly workability allowing sure fixing.SOLUTION: A first lens barrel and a second lens barrel for retaining lenses are coupled with screws, and the second lens barrel is rotatingly fed to the first lens barrel so as to adjust an interval between the lenses. While the optical performances are confirmed, the second lens barrel is rotatingly operated through an opening part provided in a lens housing. A lens barrel fixing mechanism that presses the second lens barrel in the optical axis direction to fix the lens barrel is provided adjacent to the second lens barrel. After the lens interval is adjusted, the lens barrel fixing mechanism is operated from the outside of the lens housing to fix the lens interval.

Description

  The present invention relates to an adjustment structure for adjusting the optical performance of a photographic lens.

  In the process of assembling a photographic lens having high optical performance, the lens interval is adjusted in order to obtain desired optical performance. The lens interval adjustment structure is generally a method in which a washer is inserted between two adjacent lens barrels to optimally adjust the thickness of the washer. In particular, a TV lens for HDTV, which requires a high resolving power, has many places where adjustment of a minute amount of the lens interval is required. In some cases, the product is assembled once and the thickness of the washer is adjusted after checking the optical performance. In order to replace the washer with the optimum thickness, it is necessary to disassemble the photographic lens once assembled. Therefore, the assembly work in the reverse direction causes an increase in the number of assembly steps, leading to an increase in product cost.

  In order to solve such a problem, a structure has been proposed in which the lens interval is changed by changing the relative rotational phase of the two lens barrels (see Patent Document 1). By rotating the lens barrel, the lens barrel extends in the optical axis direction, and the rotation of the lens barrel is restricted and fixed by a plurality of locking grooves.

JP 2005-91620 A

  However, this structure is a structure in which the operator grasps the lens barrel by hand and adjusts the rotation while rotating the lens barrel. When the lens barrel for adjusting the distance is located at the end of the photographing lens, it is possible to adjust the lens distance by turning the lens barrel with bare hands. However, when the lens barrel for adjusting the distance is inside the taking lens and the bare hand does not reach the lens barrel, the lens distance cannot be easily adjusted from the outside. It is not a structure that can easily adjust the distance between the lenses located inside the lens group while checking the optical performance after the photographing lens is assembled into a completed state.

  In addition, since the holding structure elastically holds the two lens barrels, a sufficient holding force necessary for firmly fixing the lens barrel cannot be obtained. In particular, in a broadcasting lens with high optical sensitivity, there is a possibility that the required optical performance is impaired by a slight movement of the lens barrel due to impact. It is not preferable as a method for holding a professional photographing lens that requires high impact resistance and does not allow a change in lens position over time for a long period of time.

  The present invention has been devised to overcome the above problems. An object of the present invention is to provide a photographing lens with good assembling workability, which can easily adjust the distance between the lenses located inside the photographing lens from the outside while checking the optical performance, and has high impact resistance.

  In order to achieve the above object, a photographic lens of the present invention has a first lens barrel and a second lens barrel that hold optical means inside a housing of the photographic lens, and the first lens barrel and the second lens barrel. In the photographic lens that adjusts the optical performance by adjusting the interval between the lens barrels, when the second lens barrel is rotated with respect to the first lens barrel, the first lens barrel and the A rotation feeding mechanism in which an interval in the optical axis direction of the second lens barrel changes, and a concavo-convex shape provided on an outer peripheral portion of the second lens barrel or a member integrally coupled to the second lens barrel; At least one or more openings provided in the casing and the second lens barrel in the optical axis direction by pressing the second lens barrel in the vicinity of the second lens barrel. A lens barrel pressing means for fixing to the cylinder is provided. The concave / convex shape is rotated from the outside of the photographing lens through the opening to adjust the distance between the first lens barrel and the second lens barrel while checking the optical performance. After the distance adjustment is completed, the lens barrel pressing means is operated from the outside of the photographing lens through the opening, and the second lens barrel adjusted by feeding is fixed to the first lens barrel.

  Furthermore, it has a motor for rotating the concave and convex shape electrically, optical performance evaluation means for evaluating the optical performance of the photographing lens, and control means for controlling the motor based on the evaluation result of the optical performance evaluation means. The position of the second lens barrel in the optical axis direction is automatically and optimally controlled automatically while confirming the optical performance of the taking lens using the optical performance evaluation means.

  For photographic lenses that require adjustment of the lens spacing, it is possible to easily adjust the distance between the lenses located inside the photographic lens from the outside while checking the optical performance. It is intended to provide.

1 is a configuration diagram of a photographic lens according to a first embodiment of the present invention. Overall configuration of the photographic lens Configuration of a photographic lens according to the second embodiment of the present invention Explanatory drawing of the fixing member which fixes a lens-barrel Sectional view of fixing means for fixing the lens barrel

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[Example 1]
A photographing lens showing an example of the present invention will be described in detail with reference to FIG. 1 in FIG. 1 represents a relay unit of a taking lens used for television shooting such as news coverage.

  In the figure, L1 and L2 are a first optical component and a second optical component, respectively, and the optical performance is adjusted by changing the interval between L1 and L2. The first optical component L1 and the second optical component L2 are held by the first lens barrel 1 and the second lens barrel 2, respectively. An interval adjusting ring 3 is disposed between the first lens barrel 1 and the second lens barrel 2. The interval adjusting ring 3 is engaged with the threaded portion 1 a of the first lens barrel 1 and is engaged with the fitting portion 1 b of the first lens barrel 1. When the interval adjusting ring 3 is rotated around the optical axis with respect to the first lens barrel 1, the interval adjusting ring 3 moves in the optical axis direction while maintaining the optical axis according to the rotation amount. The interval adjusting ring 3 is fixed with the second lens barrel 2 and the screws 4. As shown in the figure, the second lens barrel 2 and the interval adjusting ring 3 have a backlash in the radial direction, and the second lens barrel 2 is adjusted up and down, left and right with respect to the interval adjusting ring 3 and then fixed with screws 4. Reference numeral 9 denotes a mount for mounting an interchangeable photographing lens on the camera. The mount 9 is provided with eight set screws 21 at equal intervals around the optical axis. With the screw 4 temporarily fixing the second lens barrel 2 and the distance adjusting ring 3, the set screw 21 is operated from the outside of the taking lens and the outer periphery of the second lens barrel 2 is protruded. The optical component L2 is adjusted to be decentered parallel to the top, bottom, left and right with respect to the first optical component L1. After the eccentric adjustment of the second lens barrel 2, the screw 4 is tightened to fix the relative position in the radial direction between the first optical component L1 and the second optical component L2. In other words, by rotating the distance adjustment ring 3, the distance between the optical parts L1 and L2 is adjusted steplessly, and then the screw 4 is loosened slightly to adjust the second lens barrel 2 up, down, left and right in parallel to adjust the optical performance. It is adjusted. A helicoid screw 1 c is formed on the outer periphery of the first lens barrel 1 and meshes with a helicoid screw 5 c provided on the inner diameter portion of the fixed barrel 5. A flange back ring 6 is arranged on the outer periphery of the fixed cylinder 5 so as to be rotatable with respect to the fixed cylinder 5. When the flange back ring 6 is rotated, the first lens barrel 1 rotates together with the macro ring 6 through the connecting pin 7. The first optical component L1 and the second optical component L2 are rotated in the optical axis direction while rotating together to adjust the flange back of the photographing lens. A flange back fixing screw 8 is tightened after adjusting the flange back so that the flange back ring 6 does not move during photographing.

  Next, a mechanism for electrically adjusting the distance between the first optical component L1 and the second optical component L2 will be described. The fixed cylinder 5 has openings 5a and 5b for accessing the inside of the photographing lens from the outside. Further, a gear portion 3a is provided on the outer peripheral portion of the interval adjusting ring 3 all around. An intermediate gear 10 inserted into the opening 5a meshes with both the gear portion 3a of the interval adjusting ring 3 and the motor gear 12 attached to the tip of the motor 11. The motor 11 is driven by the control circuit 13 and the interval adjusting ring 3 is rotationally driven via the intermediate gear 10 to adjust the interval between the first optical member 1 and the second optical member 2 electrically. The intermediate gear 10 is inserted into the opening 5a only when the lens interval is adjusted, and is separated from the photographing lens after the adjustment. Reference numeral 14 denotes a lock screw provided in the first lens barrel 1, and the outer peripheral surface of the screw is provided with a tapered surface 14a. After adjusting the lens interval by driving the interval adjusting ring 3 with the motor 11, a screwdriver is inserted from the opening 5b provided in the fixed cylinder 5, and the lock screw 14 is tightened. The interval adjusting ring 3 is fixed by the taper surface 14 a of the lock screw 14 abutting against the tapered surface 3 b of the interval adjusting ring 3. Generally, when fixing components inside the lens from the outside of the photographic lens, it is easy to fix the screw from the outside toward the center of the optical axis from the viewpoint of workability. However, if another part is fixed to the lens barrel holding the optical part with a screw in the radial direction, the lens barrel is deformed and the optical performance is deteriorated. In this embodiment, the fixing force transmitted to the first optical component 1 is reduced by applying a force for fixing the distance adjusting ring 3 in the optical axis direction by using a tapered surface to deform the optical component 1. Is preventing. As a result, it is possible to prevent a decrease in optical performance due to coupling of adjacent lens barrels. By changing the direction of the fastening force from the outside to the optical axis direction to tighten the lock screw in the radial direction from the outside to the photographic lens, the lens barrel is securely fixed without degrading the optical performance with high workability. can do.

  In the conventional distance adjustment by changing the washer, it is impossible to adjust the distance steplessly. Therefore, it is difficult to adjust the distance optimally for a photographing lens having high sensitivity of the distance between lenses. In this embodiment, since the lens interval can be adjusted steplessly, a lens having high optical performance can be quickly assembled.

  The photographic lens of the present invention has a structure in which the interval between adjacent glasses can be adjusted from the outside of the photographic lens. In order to reduce the number of steps for assembling a photographic lens having such a structure, an adjustment device capable of automatically adjusting the lens interval while evaluating optical performance will be described below. Reference numeral 15 denotes a laser light source. A first tool lens 16 and a second tool lens 17 are arranged on both sides of the lens unit R, and the laser light emitted from the laser light source 5 includes two auxiliary optical lenses 16, Connected to CCD 18 through 17 and lens unit R. In the CCD 18, the wavefront data of the lens formed is analyzed by the image processing circuit 19 and the CPU 20. The lens interval is adjusted by feedback-controlling the motor 11 based on the image analysis result so that the interval between the first optical component L1 and the second optical component L2 is optimized. The configuration diagram excluding the relay unit R in the structural diagram shown in FIG. 1 corresponds to the adjusting device for the taking lens, and the motor 11 and the intermediate ring 10 are also included in the adjusting device. After adjusting the lens interval, the lock screw 14 is tightened to fix the relative position of the first lens barrel 1 and the second lens barrel 2 in the optical axis direction. As described above, it is possible to easily and automatically adjust the interval between the adjacent glasses from the outside, and the assembly cost can be greatly reduced.

As shown in FIG. 2, a broadcasting photographing lens is generally a focus lens group F, a variator lens group V, a compensator lens group C, a front relay lens group FR, and a variable magnification lens group that can be inserted into and retracted from the optical path. E and relay lens group R. In this embodiment, the adjustment of the distance between the lenses constituting the relay lens group R has been described. However, the present invention can be applied to the adjustment of the distance between any lens groups constituting the photographing lens. It is also possible to adjust the distance between adjacent glasses using the adjustment device shown this time in a state where a plurality of lens units are combined and assembled into a final shape. Without disassembling the taking lens, while checking the optical performance with a measuring instrument, not only the glass interval at the end of the taking lens, but also the distance between the difficultly accessible lenses located in the center of the lens can be easily adjusted from the outside can do. As a result, assembly with good workability can be realized in a short time, and the product cost can be reduced.
[Example 2]
A photographic lens according to a second embodiment of the present invention will be described with reference to FIGS. The second embodiment is different only in the fixing method of the interval adjusting ring 3 described in FIG. 1 of the first embodiment. In the structural diagram of this embodiment shown in FIG. 3, the same reference numerals as those in FIG.

  The interval between the first optical component L1 and the second optical component L2 is adjusted while checking the optical performance in the same procedure as in the first embodiment. Thereafter, a screwdriver is inserted from the opening 5b of the fixed cylinder 5, and the fixing screw 30 is tightened from the outside of the photographing lens, so that the interval adjusting ring 3 is fixed to the first lens barrel 1. Reference numeral 31 denotes a lock member. The lock member 31 has a threaded portion 31a, a slit 32b, and a tapered surface 31c as shown in FIG. When the fixing screw 30 is tightened, as shown in FIG. 5, the tapered portion 30a of the fixing screw 30 comes into contact with the tapered surface 31c of the lock member 31, and when the fixing screw 30 is further tightened, the width of the slit 32b is increased. The member 31 is elastically deformed. When the lock member 31 is elastically deformed in the optical axis direction, the interval adjusting ring 3 receives a pressing force in the optical axis direction, and the interval adjusting ring 3 can be fixed to the first lens barrel 1.

  In the second embodiment, the fixing method of the interval adjusting ring 3 after adjusting the lens interval is different from that of the first embodiment. Although the number of parts for fixing to the first embodiment increases, a force acts only in the optical axis direction when fixing the distance adjusting ring 3. In general, when another part is fixed to the lens barrel holding the optical part with screws in the radial direction, the lens barrel is deformed, leading to deterioration of optical performance. In this embodiment, when the distance adjusting ring 3 is fixed, no radial fixing force is generated. Therefore, there is no influence on the first optical component L1 and the second optical component L2, and the optical performance is deteriorated. It is possible to fix the lens interval without incurring the problem. Also in this embodiment, as in the first embodiment, the lens interval can be automatically adjusted while using the image sensor and the motor to evaluate the optical performance with an image, so that the assembly work can be made more efficient. .

L1 first optical component
L2 Second optical component
1 First barrel
2 Second barrel
3 Spacing adjustment ring
5 Fixed cylinder
5a opening
5b opening
11 Motor
13 Control circuit
14 Lock screw
18 CCD

Claims (2)

Photographing that has a first lens barrel and a second lens barrel that hold optical means inside a photographing lens housing, and adjusts the optical performance by adjusting the distance between the first lens barrel and the second lens barrel. In the lens,
When the second lens barrel is rotated with respect to the first lens barrel, the rotation extension in which the distance between the first lens barrel and the second lens barrel in the optical axis direction changes according to the amount of rotation. A mechanism, a concavo-convex shape provided in an outer peripheral portion of the second lens barrel or a member integrally coupled to the second lens barrel, at least one opening provided in the housing, and the first A lens barrel pressing means for fixing the second lens barrel to the first lens barrel by pressing the second lens barrel in the optical axis direction in the vicinity of the second lens barrel; The concave-convex shape is rotated through the opening to adjust the distance between the first lens barrel and the second lens barrel, and after the distance adjustment is completed, the lens barrel is passed through the opening from the outside of the photographing lens. The pressing means is operated to fix the second lens barrel adjusted for feeding to the first lens barrel. Shadow lens. The photographing lens includes a motor for rotating and driving the concavo-convex shape electrically, an optical performance evaluation unit for evaluating optical performance of the photographing lens, and a control unit for controlling the motor based on an evaluation result of the optical performance evaluation unit. An apparatus for adjusting a photographic lens, wherein the second lens barrel is automatically controlled to a position in the optical axis direction while confirming the optical performance of the lens.