JP2003084178A - Lens barrel caulking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel caulking device in which a constant proper pressing force always applied to a lens and the caulking precision is not affected by size variance among individual components. SOLUTION: A work is biased by a backup 1 and a compression spring 3 so that the circumferential edge 6b of a resin frame 6 abuts against a horn 4 for heating, and during caulking operation, the lens 7 receives only the proper pressing force corresponding to the biasing force.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video camera, an electronic still camera (digital still camera), and a silver halide film still camera. The present invention relates to a lens barrel caulking device for caulking and fixing a lens ball in a lens barrel in order to assemble a lens barrel assembly. 2. Description of the Related Art Conventionally, an apparatus having the following configuration has been known as a lens barrel caulking apparatus. FIG. 3 is a side view of an example of a conventional lens barrel caulking device. A control device 153 and a cylinder 154 for performing automatic operation are provided above a support 152 standing upright on a base 151. ing. A heater 155 is fixed below the rod 154a of the cylinder 154, and a pipe-like (cylindrical) horn 15 having a tapered lower end surface is provided below the heater 155.
6 are provided. On the other hand, a base 157 is fixed on a base 151, and a lens barrel 158 formed of a heat-fusible member such as a resin material is mounted on the base 157. A lens ball 159 is inserted into the lens barrel 158 from one opening side. And the lens barrel 158
And the axis of the horn 156 are on the same axis. [0005] The device having the above-described structure is a cylinder 15
4, the horn 156 is lowered, and the horn 156 is attached to the peripheral edge 158a of the opening at the upper end surface of the lens barrel 158.
Abut. At this time, since the horn 156 is heated by the heater 155, the peripheral edge 158a with which the horn 156 contacts is heated and deformed under pressure. Thereafter, the horn 156 rises, and the peripheral edge 158 a deformed under pressure around the lens ball 159 moves the lens ball 159 to the lens barrel 15.
The device was configured to be swaged in 8. [0006] The lens barrel caulking device according to the prior art described above has the following unsolved problems. First, when the conventional lens barrel caulking device performs the "caulking" operation, the horn 156 lowered toward the workpiece (the lens barrel assembly for caulking).
Keeps pressing the peripheral edge 158a even after contacting the peripheral edge 158a of the lens barrel 158. Further, the base 157 on which the work is placed is fixedly disposed on the base 151. For this reason, the work is sandwiched between the horn 156 and the base 157 and is pressed from both sides.
The resin material of the peripheral edge 158a that has been heated and deformed by the pressure by 56 continues to receive the pressing force directly from the horn 156 while the horn 156 contacts. As a result, the molten resin material that has received the pressing force presses the lens ball 159 against a predetermined seating surface in the lens barrel 158 this time. Then, after the lens ball 159 is positioned following the above-mentioned seating surface,
Since the surface is fixed by caulking, the surface accuracy of the seat surface greatly affects the surface accuracy of the lens ball after caulking. On the other hand, a lens barrel made of a resin material
Looking at individual components, they have dimensional variations due to deformation and the like during resin molding, and the surface accuracy of the above-mentioned seating surface has a tolerance of, for example, about 20 μm. And, as described above, if the horn directly presses the lens ball against the bearing surface having such a variation, the lens is swung due to the variation in the surface accuracy of the bearing surface, and the lens after swaging is formed. The surface accuracy of the balls also has a large variation, and there has been a problem that it is difficult to maintain a predetermined optical performance in a video camera or the like in which a lens mirror or the like after assembly is disposed. For example, when a lens ball having a positive power of about 20 mm in diameter and about 4 mm in thickness at the center is caulked and fixed in a resin-molded lens barrel having a seat surface having a variation of about 20 μm as described above, It has been found by the present inventors that the surface accuracy of the lens ball deteriorates by about 0.3 μm. By the way, in recent years, the size and weight of an image pickup apparatus in which a lens barrel assembled by this type of caulking operation is disposed have been increasingly reduced, and accordingly, the optical system configuration has also been reduced in size. In. In a miniaturized optical system, the surface accuracy of each lens ball is required to be higher than before. As described above, despite the demand for higher precision than ever before, it is impossible to caulk and fix the lens ball with sufficient precision due to dimensional variations of the seating surface of the lens barrel. In an attempt to resolve the above issues,
Several proposals have been made, including: (1) A method of restricting the lowering position of the horn. This is because, when the horn is lowered with respect to the lens barrel, a stopper is provided to regulate the lower limit of the height of the horn with respect to the lens barrel, so that the horn does not press the molten resin more than necessary, and This is to prevent the surface accuracy from being deteriorated. (2) A method of providing a plurality of contact points on a lens seat surface in a lens barrel. As a configuration in which the bearing surface in the lens barrel does not abut on the lens ball at the entire circumference, but abuts at only three points, for example.
The purpose is to make it easier to manage the surface accuracy of the seat surface, and as a result, to improve the surface accuracy of the lens ball after caulking. (3) A method in which the lens barrel is made of a metal material. This is because the lens barrel is formed by cutting or die-casting a metal member instead of a hot-melt resin material or the like, and thus fixing the lens ball by another method not depending on heating and pressure deformation. This is a method for improving the surface accuracy of a lens ball. However, in each of the above-mentioned methods, the above-mentioned problems cannot be essentially solved for the following reasons. That is, in the "(1) Method for limiting the lowering position of the horn", it is assumed that the lowering position of the horn in the caulking device is limited by the dimensional variation of each lens barrel and the dimensional variation of each lens ball. However, the relative position at which the horn descends with respect to the lens barrel and lens ball varies, and as a result, the lens ball is pushed with an excessive pressing force for a certain work, as before, and the surface accuracy is deteriorated. In addition, other workpieces may not be sufficiently contacted with the horn, so that heating and pressing may not be performed properly. That is, the degree of the pressing force of the horn on the peripheral edge and the lens ball varies, so that the optimal fixing of the lens ball cannot be realized. To solve the above problem, the dimensional variation of each part is measured in advance, and the lowering limit position of the horn is adjusted for each work in accordance with the measured value of each work, so that the pressing force of the horn is It is easy to recall a method that attempts to solve the problem within a certain range. However, the adjustment width of the lowering limit position is extremely small and critical, and it is difficult to perform appropriate adjustment. In addition, the dimensions of individual parts are measured in advance, and adjustment is performed in accordance with the measured values. Performing the caulking operation greatly reduces the workability, and it is actually extremely difficult to execute. Also in "(2) a method of providing a plurality of contact points on the lens seat surface in the lens barrel", the fact that these plurality of contact surfaces have dimensional variations associated with resin molding is not changed. There was no change in the point that the surface accuracy was deteriorated in the lens ball having the plurality of contact points, so that it was not an essential solution. Further, according to "(3) Method of constructing lens barrel of metallic material", a method of thermocompression bonding of resin lens barrel which reduces parts cost and realizes high productivity is abandoned. As a result, there was a problem that the cost increased and the productivity decreased. The present invention has been made in view of the above circumstances, and particularly, a lens ball is inserted into one end opening of a lens barrel, and a peripheral edge of the end opening is heated and heated. A lens barrel caulking device for caulking and fixing a lens ball in a lens barrel by deforming under pressure. The lens barrel caulking device is movable so as to approach and separate from a lens barrel at a predetermined position, and is in an approaching state. The one end of the cylindrical metal part heated in step abuts on the peripheral edge of the lens barrel to perform heating and pressure deformation of the peripheral edge, and approaches and separates from the horn part in the close state. The mounting table for mounting the lens barrel, which is configured to be movable, one end of the horn portion in the close state, and the peripheral edge of the lens barrel mounted on the mounting table are in contact with each other. Hold the mounting table with the specified biasing force to maintain A lens mirror provided with biasing means for biasing the lens portion so that only a pressing force corresponding to the biasing force of the biasing means is applied to the lens ball when the peripheral edge is heated and deformed by pressure. By using a tube caulking device, the pressing force applied to the lens ball during the caulking operation is always within the optimum range, and even when there is a dimensional variation among parts, the above pressing force is always within the optimum range. Accordingly, an object of the present invention is to provide a lens barrel caulking device capable of caulking and fixing a lens ball in a resin lens barrel with high accuracy. In order to solve the above problems, the present invention provides a lens barrel swaging apparatus having the following configuration. That is, the lens barrel (resin frame) 6
The lens ball 7 is inserted into the lens barrel 6 from one end opening 6a, and the peripheral edge 6b of the end opening 6a is heated and pressed to deform the lens ball 7 into the lens barrel 6. A lens barrel swaging device for fixing, which is movable so as to approach and separate from the lens barrel 6 at a predetermined position, and one end 4a of the cylindrical metal portion heated in the approached state. A horn portion 4 which abuts on the peripheral edge 6b of the lens barrel 6 to heat and deform the peripheral edge 6b;
A mounting table (backup) 1 on which the lens barrel 6 is mounted so as to be movable so as to approach and depart from the camera; the one end 4a of the horn 4 in the approaching state; Urging means for urging the mounting table 1 toward the horn portion 4 with a predetermined urging force so as to maintain a contact state with the peripheral edge 6b of the lens barrel 6 mounted on the mounting table 1 (Compression spring) 3 so that only a pressing force according to the urging force of the urging means 3 is applied to the lens ball 7 when the peripheral edge 6b is heated and deformed under pressure. This is a lens barrel caulking device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2,
A description will be given of a lens barrel swaging apparatus which is a preferred example according to the embodiment of the present invention. FIG. 1 is a sectional view of a lens barrel assembly, which is a work of the lens barrel swaging apparatus of the present embodiment, and FIG. 2 is a sectional view of a main part of the lens barrel swaging apparatus of the present embodiment. As shown in the sectional view of FIG. 1, the lens barrel assembly 5 in which the lens barrel caulking device of this embodiment performs the caulking is provided with a resin frame 6 and an opening 6a of the resin frame 6. And a lens 7 fixed by caulking. In the opening 6a of the resin frame 6, a seating surface 6c which contacts the inserted lens 7 and supports the lens 7 is provided.
Is provided. A peripheral edge 6 is provided around the opening 6a.
b is provided, and the peripheral edge 6b heated by the horn 4 is deformed under pressure as described later, whereby the lens 7 is fixed by caulking into the lens barrel 6. FIG. 2 is a sectional view of a main part of the lens barrel swaging apparatus of the present embodiment. Here, FIG. 2 mainly shows characteristic portions of the lens barrel caulking device,
As a portion not shown, a base on which the base 2 is mounted and fixed, a column extending upward from the base, and a cylinder disposed above the base 2 and the like to support the horn 4 by the column , A heater arranged near the horn 4 for heating the horn 4, and various actuators and control means. These unillustrated configurations may be configured, for example, according to the prior art lens barrel caulking device shown in FIG. 3, or may be configured based on other known technologies. Referring to FIG. 2, the characteristic structure of the lens barrel caulking device of the present embodiment will be sequentially described. First, the base 2 is mounted and fixed on a base (not shown). A through-hole is formed in the center axis of the base, and a backup 1 is provided so as to be movably fitted into the through-hole so as to be movable within a predetermined range in the vertical direction in the illustrated posture. A compression spring (compression spring) 3 is disposed in the through hole of the base 2 and urges the backup 1 upward in the illustrated posture. On the other hand, the backup 1 which fits into the through hole of the base 2
A disc-shaped stopper 1a is disposed at the lower end of the backup 1. When the stopper 1a contacts the base 2, the backup 1 is prevented from moving further upward. Further, the backup 1 that has moved downward contacts the upper surface of the base 2 to prevent further movement downward. That is, backup 1
It is configured to be vertically movable within the above-mentioned predetermined range with respect to the base 2, and is urged upward by the compression spring 3 so that the vertical movement range is free when no downward external force is applied. It is configured to be located at the upper end. The upper surface of the backup 1 has a shape for mounting a lens barrel assembly for caulking. The horn 4 has a tapered cross section at its lower end, and the horn 4 lowered by a cylinder (not shown) is moved to a predetermined position which is a relative position in the apparatus by a horn stopper (not shown). Is configured to be regulated. Next, the operation of caulking the lens barrel assembly of FIG. 1 using the lens barrel caulking device having the above-described configuration will be described sequentially with reference to FIG. (First Step-Caulking Standby Stage-FIG. 2)
(A)) When the caulking operation is performed, first, the resin frame 6
The lens barrel 7 is inserted into the opening 6a, and the lens barrel assembly 5 in this state is mounted on the upper surface of the backup 1 (FIG. 2A). At this time, the gravity of the mounted lens barrel assembly 5 is sufficiently smaller than the urging force of the compression spring 3, so that the backup 1 is still at the upper end of the vertical movement range. (Second Step—Caulking Start Stage—FIG. 2)
(B)) Next, the horn 4 is lowered toward the work (the lens barrel assembly 5) by performing a predetermined operation of the lens barrel caulking device. As the horn 4 descends, the horn 4 first comes into contact with the upper end surface of the peripheral edge 6 b of the resin frame 6, and further lowers the work together with the backup 1 against the urging force of the compression spring 3. Then, the lowering of the horn 4 is stopped by a horn stopper (not shown), and the resin frame 6 is stopped in the stopped state.
Is heated and pressurized by the horn 4 and deformation starts. At this time, backup 1 for placing the work
Is constantly urged upward by the compression spring 3, so that even when the peripheral edge 6b is deformed under pressure, the upper end surface of the peripheral edge 6b always comes into contact with the lower end surface of the horn 4, so that heating and pressurizing are not performed. There is no interruption. Similarly, the urging action of the compression spring 3 causes the lens ball 7 to be sandwiched between the horn 4 and the seating surface with a weak moderate pressing force. Nothing to do. Further, the biasing force of the compression spring 3 can be set to an appropriate magnitude enough to lift the backup 1 on which the work is placed upward and abut against the horn 4. As a result, since the resin material and the lens ball 7 do not receive an unnecessarily large pressing force from the horn 4, there is an effect that the surface accuracy of the lens ball after crimping can be maintained satisfactorily. Furthermore, even if the resin frame 6 or the lens ball 7 has a dimensional variation for each component, the dimensional variation is sufficiently absorbed in the process of lowering the backup 1 together with the work, so that the horn The above variation does not affect the pressing force applied to the workpiece from 4
Therefore, it is possible to suppress the influence of the variation in the component size on the surface accuracy of the lens ball 7 after the caulking. (Third Step-End Stage of Caulking-FIG. 2)
(C) Next, when the progress of the heating and pressurizing deformation of the peripheral edge 6b of the resin frame 6 reaches a state sufficient to perform caulking, a predetermined operation in the caulking device is performed,
Horn 4 starts to rise. Initially compression
The work, the backup 1 and the horn 4 rise together as a result of the urging force of the spring 3. However, when the upper limit of the movement range of the backup 1 is reached, the work and the backup 1 stop, and only the horn 4 continues to rise. 4 is separated from the deformed resin material of the peripheral edge 6b. The resin material is molded around the lens ball 7, and a series of operations for caulking and fixing the lens ball 7 inside the resin frame 6 are completed. Advantageous points based on the configuration of the lens barrel caulking device of the present embodiment described above are as follows. (1) Since the lens ball does not receive an excessive pressing force from the horn, the surface accuracy of the lens ball after caulking is improved. As described above, in the caulking operation, the work is pressed against the horn only by the urging force of the compression spring 3. In addition, the compression spring 3 is provided so that the contact between the horn and the resin frame is maintained, the heating is not interrupted, and the compression spring 3 has an appropriate urging force enough to hold the lens ball so as not to be distorted during caulking. It is easy to configure. That is, according to the lens barrel caulking device of the present embodiment, the surface accuracy of the lens ball after caulking can be improved by preventing the lens ball from receiving an excessive pressing force from the horn. (2) Even if the resin frame or the lens ball has a dimensional variation for each part, the surface accuracy of the lens ball after caulking can be maintained at a high level without being affected by this. . As described above, even if the individual component dimensions of the resin frame or the lens ball vary, this variation is sufficiently absorbed in the vertical movement amount of the backup 1 that is configured to be vertically movable, and the horn transfers the lens ball to the lens ball. There is no effect on the applied pressing force. Therefore, the above-described pressing force varies due to variations in the dimensions of individual components, and as a result, there is an effect of solving the problem in the conventional configuration that the surface accuracy of the lens ball after crimping deteriorates. Since the lens barrel caulking device of this embodiment has a special structure as described in detail above, it has the advantageous effects which have not been obtained in the prior art as described in the above (1) and (2). Demonstrate. Further, as compared with the conventional configuration, the operation time for the caulking operation is not particularly extended, and a caulking device can be realized at low cost. Further, when the inventors of the present invention conducted a study of actually performing the caulking operation using the lens barrel caulking device of the present embodiment,
With a positive power lens ball having a center thickness of about 4 mm, the accuracy of the lens ball surface after caulking can be about 0.03 μm, and a surface of about 0.3 μm when a caulking device according to the prior art is used. Since the results obtained were reduced to about 1/10 compared to the accuracy, the present inventors could confirm the above-mentioned respective effects. As described above, according to the present invention, a lens ball is inserted from one end opening into a lens barrel, and the peripheral edge of the end opening is deformed by heating and pressing. A lens barrel caulking device for caulking and fixing a lens ball in a lens barrel by moving the lens barrel close to and away from a lens barrel at a predetermined position, and a cylinder heated in a close state. A horn part where one end of the metal-shaped part contacts the peripheral edge of the lens barrel to heat and deform the peripheral edge, and is movably configured to approach and separate from the horn part in the close state The mounting table for mounting the lens barrel, the one end of the horn portion in the approaching state, and the peripheral edge of the lens barrel mounted on the mounting table are maintained in a predetermined state so as to maintain the contact state. With the urging force of the above, the mounting table is urged to the horn side. A lens barrel caulking device, characterized in that the lens barrel is provided with a biasing means so that only a pressing force corresponding to the biasing force of the biasing means is applied to the lens ball when the peripheral edge is heated and pressurized and deformed. By setting the pressing force applied to the lens ball at the time of caulking operation always within an optimum range, and even when there is a dimensional variation among components, the above-mentioned pressing force is always within the optimum range. A lens barrel caulking device capable of caulking and fixing a lens ball in a cylinder with high accuracy can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a lens barrel assembly which is a work of a lens barrel caulking device of one example according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a main part of the lens barrel swaging apparatus according to the present embodiment. FIG. 3 is a side view of a lens barrel swaging apparatus according to the related art. [Description of Signs] 1 Backup (mounting table) 3 Compression spring (biasing means) 4 Horn (horn part) 4a One end of horn (one end of cylindrical metal part) 6 Resin frame (lens barrel) 6a Resin Opening of frame (end opening) 6b Peripheral edge 7 Lens ball

Claims (1)

Claims: 1. A lens ball is inserted into a lens barrel from one end opening thereof, and a peripheral edge of the end opening is heated and pressed to deform the lens ball. A lens barrel caulking device for caulking and fixing the lens barrel in the lens barrel, wherein the cylindrical body is movable so as to approach and separate from the lens barrel at a predetermined position, and is heated in the close state. A horn part in which one end of the metal part abuts on the peripheral edge of the lens barrel to perform heating and pressure deformation of the peripheral edge; and moves so as to approach and separate from the horn part in the close state. A freely-configured mounting table for mounting the lens barrel, the one end of the horn portion in the approaching state, and the peripheral edge of the lens barrel mounted on the mounting table. Specified to maintain contact Urging means for urging the mounting table to the horn side with the urging force of the lens, wherein only the pressing force corresponding to the urging force of the urging means at the time of heating and pressurizing deformation of the peripheral edge is the lens. A lens barrel caulking device characterized by being configured to be added to a ball.