JP4879116B2 - Lens holding method - Google Patents

Description

  The present invention relates to a lens holding method applied to manufacture of a lens barrel.

As a conventional lens holding method, for example, two methods described in Patent Document 1 are known. In a first lens holding method described in Patent Document 1, a lens is placed in a lens frame, and the lens and the lens frame are arranged in a lens barrel, and the optical axis is used with a tool from a direction orthogonal to the optical axis. After the lens is aligned, the lens is fixed to the lens barrel by tightening the presser foot from the optical axis direction. The second lens holding method described in Patent Document 1 is a method of aligning the optical axis by fastening a screw member from a direction orthogonal to the optical axis and fixing the lens to the lens barrel.
Japanese Unexamined Patent Publication No. 5-45550

  However, in the first lens holding method, since the presser bar is tightened from the optical axis direction when the lens is fixed to the lens barrel, the optical axis position of the aligned lens may be shifted. In the second lens holding method, the optical axis is aligned and the lens is fixed to the lens barrel with the same screw member. Therefore, the lens is mounted on the lens barrel while the optical axis is aligned. It may be difficult to fix.

  Accordingly, the present invention has been made to solve such a technical problem, and provides a lens holding method capable of reliably holding a lens on a lens holding frame in a state where an optical axis is aligned. For the purpose.

  That is, the lens holding method according to the present invention is a lens holding method for holding the lens on the lens holding frame, and the lens is arranged in the lens holding frame and pressed from the direction substantially orthogonal to the optical axis of the lens. Using a plurality of temporary fixing jigs, the lens is moved relative to the lens holding frame in a plane substantially orthogonal to the optical axis, and the lens is held in a state where the optical axis of the lens is aligned. And temporarily holding the lens from the direction substantially orthogonal to the optical axis of the lens by using a plurality of fixing members that press the lens from the direction substantially orthogonal to the optical axis of the lens after the temporary fixing step. The fixing process includes a fixing process for fixing to the frame, and a removing process for removing the temporary fixing jig from the lens holding frame after the fixing process is completed.

Furthermore, the temporary fixing jig is a temporary fixing screw that is screwed into a temporary fixing screw hole formed in the lens holding frame so as to penetrate in a direction substantially orthogonal to the optical axis of the lens. It is a fixing screw that is screwed into a fixing screw hole formed in the lens holding frame so as to penetrate in a direction substantially perpendicular to the optical axis, and the adjustment portion of the temporary fixing screw protrudes outward from the adjustment portion of the fixing screw. It is characterized by.

According to the present invention, the optical axis of the lens is aligned by the temporary fixing jig that presses the lens from the direction substantially orthogonal to the optical axis of the lens, and the lens is temporarily fixed and temporarily fixed in the lens holding frame. In this state, the lens is fixed to the lens holding frame by a fixing member that presses the lens from a direction substantially orthogonal to the optical axis of the lens. As a result, when the lens is pressed and fixed to the lens holding frame by the fixing member, it is possible to prevent the optical axis position of the aligned lens from being shifted, and the lens can be operated with the optical axis aligned. It is possible to securely hold the lens holding frame.

In addition, according to the present invention, since the adjustment portion of the temporary fixing screw protrudes outside the adjustment portion of the fixing screw, the optical axis of the lens can be easily aligned.

Here, after completion of the fixing process, injection is performed to inject an adhesive into the lens-side gap of the lens holding frame through a through hole formed in the lens holding frame so as to penetrate in a direction substantially orthogonal to the optical axis of the lens. It is preferable to include a process.

  According to this invention, the relative position between the lens and the lens holding frame can be more firmly fixed using the adhesive.

  According to the present invention, the lens can be reliably held on the lens holding frame in a state where the optical axis is aligned.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same or an equivalent part, and the overlapping description is abbreviate | omitted.

  The lens holding method according to the present embodiment is a method for holding a lens on a lens holding frame, and is suitably used when, for example, an inner focus type optical system is adopted in a single-lens reflex interchangeable lens.

  First, the configuration of a lens barrel manufactured by applying the lens holding method according to the present embodiment will be described. FIG. 1 is a cross-sectional view of a lens barrel manufactured by applying a lens holding method according to an embodiment of the present invention and a camera equipped with the lens barrel. As shown in FIG. 1, the lens barrel 1 is connected to the camera 2 on the rear end side (right side in the figure), and forms an image of the subject input from the front end side (left side in the figure) on the light receiving unit of the camera 2. It has a function. The lens barrel 1 includes a cylindrical barrel 5, and a plurality of lenses are accommodated in the barrel 5. Specifically, the adjustment lens 3 is arranged in a lens holding frame forming a part of the lens barrel on the front end side, and the focus lens 6 and the fixed lenses 7 to 9 are arranged on the rear end side of the adjustment lens 3. Yes. The focus lens 6 and the fixed lenses 7 to 9 are fitted and fixed in the lens barrel 5, and a gap formed between the inner wall of the lens barrel 5 and each lens is about 0.01 to 0.03 mm. Degree.

  The adjustment lens 3 has a function for correcting the optical axis shift of the lens group disposed in the lens barrel 5. The focus lens 6 is a lens for focusing on the subject, and reciprocates in the range from A (infinity setting) in FIG. 1 to B (closest setting) in FIG. It is configured to be possible. On the other hand, the fixed lenses 7 to 9 are fixed in the lens barrel 5 and have a function of changing the size of an image input from the front end side of the lens barrel 1 or forming an image. Each lens 3, 6-9 is formed, for example with glass.

  Next, the lens holding structure of the adjustment lens 3 will be described. 2 is a cross-sectional view showing a lens holding structure at the tip of the lens barrel shown in FIG. 1, FIG. 3 is a cross-sectional view taken along line III-III shown in FIG. 2, and FIG. 3 is a partially enlarged sectional view of FIG.

  As shown in FIGS. 2 and 3, the lens barrel 1 includes a lens holding structure 15 for holding the adjustment lens 3 on a lens holding frame 4 that constitutes a part of the barrel 5. The lens holding frame 4 forming a part of the lens barrel 5 is configured to be removable from the lens barrel 5, and the inner diameter of the lens holding frame 4 is formed larger than the outer diameter of the adjustment lens 3. As shown in FIG. 4, the lens holding frame 4 is formed with a fixing screw hole 4 b screwed into the fixing screw (fixing member) 11 so as to penetrate in a direction substantially perpendicular to the optical axis L (see FIG. 2). Has been. Here, “substantially orthogonal” means that an error in the manufacturing process is included, and hereinafter, the same meaning is used in the description. The fixing screw holes 4b are formed at four locations at almost equal intervals so as to face each other in the diameter direction. Further, as shown in FIG. 3, a fixing screw 11 is screwed into each fixing screw hole 4b, and the adjustment lens 3 is pressed in a direction substantially orthogonal to the optical axis L so that a predetermined inside of the lens holding frame 4 is obtained. It is fixed in position. Further, the fixing screw 11 has an adjusting portion 11a for operating the screwing amount.

  As shown in FIG. 4, the elastic member 12 is disposed inside the fixing screw hole 4 b and is interposed between the fixing screw 11 and the adjustment lens 3. The fixing screw 11 presses the adjustment lens 3 via the elastic member 12. The elastic member 12 is formed in a spherical shape with a synthetic resin having a Young's modulus of 1 to 10 GPa at room temperature (20 to 25 ° C.), for example.

  The lens holding frame 4 is formed with a plurality of through holes 4 c for injecting an adhesive material so as to penetrate in a direction substantially orthogonal to the optical axis L, and a gap between the adjustment lens 3 and the lens holding frame 4. Is filled with the adhesive 13 through the through hole 4c. The gap formed between the adjustment lens 3 and the lens holding frame 4 is, for example, about 0.1 to 0.2 mm.

  Further, a temporary fixing screw hole 4 a for screwing a temporary fixing screw (temporary fixing jig) 10 that presses the adjustment lens 3 from a direction substantially orthogonal to the optical axis L of the adjustment lens 3 to the lens holding frame 4. Is formed so as to penetrate in a direction substantially orthogonal to the optical axis L. The temporary fixing screw holes 4a are formed at four locations so as to correspond to the fixing screws 4b.

  On the other hand, the lens barrel 5 is opened at a location where the lens holding frame 4 is accommodated so that the corresponding temporary fixing screw hole 4a and fixing screw hole 4b and at least one adjacent through hole 4c are exposed to the outside. Part 5a is formed.

  According to the lens holding structure 15 described above, a plurality of fixing screw holes 4b are formed in the lens holding frame 4 so as to penetrate in a direction substantially orthogonal to the optical axis L, and therefore screwed into each fixing screw hole 4b. The adjustment lens 3 and the lens holding frame 4 can be fixed by the fixing screw 11 to be fixed. As described above, the adjustment lens 3 can be directly fixed to the lens holding frame 4 by the fixing screw 11, so that the lens holding structure 15 can be reduced in size. Further, when the adjustment lens 3 is fixed to the lens holding frame 4, since the elastic member 12 is disposed between the adjustment lens 3 and the fixing screw 11, the thermal expansion coefficient between the adjustment lens 3 and the lens holding frame 4. It is possible to prevent the adjustment lens 3 from being damaged or the adjustment lens 3 from being displaced by causing the elastic member 12 to absorb the stress generated by the difference between the two and the external force applied from the outside. Therefore, by adopting such a lens holding structure 15, it is possible to reduce the size of the lens holding structure 15 while preventing the photographing performance from being deteriorated according to use.

  Further, since the lens holding structure 15 includes the adhesive 13 disposed in the gap on the adjustment lens 3 side of the lens holding frame 4, the relative position between the adjustment lens 3 and the lens holding frame 4 is fixed more firmly. In addition, impact resistance can be improved.

  The lens barrel 1 whose optical axis is aligned is connected to the camera 2 on the rear end side and inputs an image from the front end side. The image input from the front end side of the lens barrel 1 is emitted so that the optical axis shift of each of the lenses 6 to 9 is corrected when passing through the adjustment lens 3. The image that has passed through the adjustment lens 3 is enlarged, reversed, or focused by the lens group and reaches the camera 2. As a result, a high-quality image that has been subjected to predetermined enlargement / deformation can be taken by the camera 2.

  Next, a method for manufacturing the lens barrel 1 will be described.

  First, each part which comprises the lens barrel 1 is prepared, and each part is assembled. That is, the focus lens 6 and the fixed lenses 7 to 9 are fixed in the lens barrel 5, and the adjustment lens 3 is disposed in the lens holding frame 4 that forms a part of the lens barrel 5.

  In this state, a temporary fixing step is performed using the temporary fixing screw 10 in order to correct the optical axis deviation of the lenses 6 to 9. For example, as shown in FIG. 4, the temporary fixing screw 10 includes a screw portion 10b screwed into a temporary fixing screw hole 4a formed in the lens holding frame 4, and an adjustment portion 10a having a diameter larger than that of the screw portion 10b. The tip of the screw portion 10b is chamfered so as not to damage the surface of the adjustment lens 3. The adjustment portion 10a of the temporary fixing screw 10 is formed so as to protrude outward from the adjustment portion 15a of the fixing screw 11 for fixing the adjustment lens 3 when the adjustment portion 10a is attached to the lens holding frame 4 in the temporary fixing step. Has been. As a result, the optical axis can be aligned more quickly and more accurately than when the fixing screw 11 is adjusted to align the optical axis, so that the manufacturing cost can be reduced.

  The temporary fixing screw 10 is inserted into the opening 5a formed in the lens barrel 5, screwed into the temporary fixing screw hole 4a of the lens holding frame 4, and the adjusting portion 10a of the temporary fixing screw 10 is pinched to adjust the screwing amount. It is changed and brought into contact with the adjustment lens 3. As shown in FIG. 3, the temporary fixing screws 10 are mounted at four positions at almost equal intervals facing the outer periphery of the lens barrel 5.

  After attaching the temporary fixing screw 10, parallel light enters the lens barrel 1 from the front end side of the lens barrel 1, confirms the light emitted from the rear end side, and aligns the optical axis L of the adjustment lens 3. . For example, each lens can be confirmed by visually confirming that light passing through the adjustment lens 3, the focus lens 6, and the fixed lenses 7 to 9 is output at a predetermined position so as to be focused and close to a perfect circle. It is confirmed whether or not the optical axis deviation of 6 to 9 has been corrected. If the optical axis deviation is not corrected, while adjusting the emitted light, adjust the adjustment part 10a of the temporary fixing screws attached to the four locations, change the screwing amount, and press the adjustment lens 3 to adjust. The lens 3 is moved in a plane substantially orthogonal to the optical axis L, and the optical axis L of the adjustment lens 3 is aligned so that the optical axis shift of the lenses 6 to 9 is corrected.

  By aligning the optical axis L of the adjustment lens 3 in this way, the optical axis deviation of the lenses 6 to 9 in the lens barrel 1 is corrected with the fixed lenses 7 to 9 and the focus lens 6 attached. Can do. In addition, since the alignment of the optical axis L can be performed from the outside of the lens barrel 5, when the injection step described later is not performed, the lens barrel 1 can be executed even after it is assembled. When the alignment of the optical axis L is completed, the adjustment lens 3 is temporarily fixed to the lens holding frame 4 by the temporary fixing screw 10.

  When the temporary fixing step is completed, a fixing step of fixing the relative position between the adjustment lens 3 and the lens holding frame 4 is performed. As shown in FIG. 4, with the temporary fixing screw 10 still attached, the elastic member 12 is inserted through the opening 5a formed in the outer lens holding frame and inserted into the fixing screw hole 4b. Thereafter, the fixing screw 11 is inserted into the opening 5a, screwed into the fixing screw hole 4b, and mounted, and the elastic member 12 is pressed by screwing, thereby pressing the adjustment lens 3 via the elastic member 12. The elastic member 12 and the fixing screw 11 are mounted at four locations facing the outer periphery of the lens barrel 5.

  Thus, since the relative position of the adjustment lens 3 and the lens holding frame 4 can be fixed with the temporary fixing screw 10 attached, the adjustment lens is fixed by tightening for fixing after aligning the optical axis. 3 can be prevented from shifting relative to the lens holding frame 4. Further, since the fixing screw 11 only needs to have a fixing function, the adjustment portion 15a of the fixing screw 11 can be formed smaller, and thus the lens barrel 1 can be reduced in size.

  Further, since the elastic member 12 is disposed between the adjustment lens 3 and the fixing screw 11, stress generated by the difference in thermal expansion coefficient between the adjustment lens 3 and the lens holding frame 4, an external force applied from the outside, and the like. Since it is absorbed by the elastic member 12, it is possible to avoid damaging or destroying the adjustment lens 3 and shifting the centering position of the adjustment lens 3.

  When the fixing step is completed, a removal step of removing the temporary fixing screw 10 from the lens barrel 5 and the lens holding frame 4 is performed. In the removal step, the temporary fixing screw 10 is removed by performing an operation opposite to the operation of attaching the temporary fixing screw 10.

  When the removal step is completed, the alignment of the optical axis L of the adjustment lens 3 is completed, and the adjustment lens 3 has a function for correcting the optical axis deviation of the lenses 6 to 9 arranged in the lens barrel 5. It becomes. Here, in order to fix the relative position of the adjustment lens 3 and the lens holding frame 4 more firmly, an injection step of injecting the adhesive 13 is performed after the removal step. In the injection step, the adhesive 13 is injected into the through hole 4 c formed in the lens holding frame 4, and the adhesive 13 is filled in the gap on the adjustment lens 3 side of the lens holding frame 4, so that the adjustment lens 3 and the lens holding frame 4 are filled. And fix. In addition, as shown in FIG. 3, about the through-hole 4c which does not correspond to the opening part 5a formed in the lens barrel 5, the adhesive material 13 was inject | poured into the through-hole 4c corresponding to the opening part 5a, and was hardened. Then, after removing the lens holding frame 4 from the lens barrel 5, the adhesive 13 is injected.

  Fixing with the adhesive 13 in this way can prevent the relative position between the adjustment lens 3 and the lens holding frame 4 from shifting and the optical axis L of the lens group in the lens barrel 1 from shifting, and Impact resistance can be improved. Reinforcement with the adhesive 13 is particularly effective when the adjustment lens 3 is relatively heavy and there is a possibility that the relative position between the adjustment lens 3 and the lens holding frame 4 may shift due to the load.

  As described above, according to the lens holding method according to the present embodiment, the optical axis L of the adjustment lens 3 is aligned by the temporary fixing screw 10 that presses the adjustment lens 3 from a direction substantially orthogonal to the optical axis L of the adjustment lens 3. At the same time, the adjustment lens 3 is temporarily fixed in the lens holding frame 4, and the adjustment lens 3 is fixed to the lens by a fixing screw 11 that presses the adjustment lens 3 from a direction substantially orthogonal to the optical axis L of the adjustment lens 3. It is fixed to the holding frame 4. Accordingly, when the adjustment lens 3 is pressed and fixed to the lens holding frame 4 with the fixing screw 11, it is possible to avoid the optical axis L position of the adjusted adjustment lens 3 from being shifted. It is possible to securely hold the adjustment lens 3 on the lens holding frame 4 in the aligned state.

  Further, according to the lens holding method according to the present embodiment, since the adjustment portion 10a of the temporary fixing screw 10 protrudes outside the adjustment portion 11a of the fixing screw 11, the alignment of the optical axis L of the adjustment lens 3 is performed. It can be done easily.

  Further, according to the lens holding method according to the present embodiment, the temporary fixing screw hole 4a into which the temporary fixing screw 10 is screwed is formed so as to correspond to the fixing screw hole 4b into which the fixing screw 11 is screwed. In the fixing step, it is possible to further suppress the occurrence of misalignment due to the fixing of the adjustment lens 3 with the adjusted optical axis L.

  Furthermore, according to the lens holding method according to the present embodiment, the relative position between the adjustment lens 3 and the lens holding frame 4 can be more firmly fixed using the adhesive 13.

  The above-described embodiment shows an example of the lens holding method according to the present invention. The lens holding method according to the present invention is not limited to the lens holding method according to the embodiment, and the lens holding method according to the embodiment may be modified or otherwise changed without changing the gist described in each claim. It may be applied to a thing.

  For example, in the above-described embodiment, the inner focus type optical system has been described. However, the present invention can also be applied to an overall focus, front focus, or rear focus optical system, and the optical axis is also adjusted in such an optical system. The centered lens can be accurately fixed.

  In the above-described embodiment, the adjustment lens 3 is described as a concave lens, but the adjustment lens 3 may be a convex lens.

  Moreover, although the shape of the elastic member 12 was demonstrated as spherical shape in embodiment mentioned above, it is not specifically limited to a shape, For example, plate shape may be sufficient. Further, even when a metal sphere or the like is disposed between the fixing screw 11 and the adjustment lens 3 instead of the elastic member 12, the elastic member 12 is generated due to a difference in thermal expansion coefficient between the adjustment lens 3 and the lens holding frame 4. It is possible to avoid the adjustment lens 3 from being damaged or the adjustment lens 3 from being displaced due to stress or external force applied from the outside. An example of the metal to be used is iron, and the Young's modulus is preferably about 200 GPa at room temperature (20 to 25 ° C.), for example.

  In the above-described embodiment, an example in which four temporary fixing screws 10 are temporarily fixed has been described. However, three or five or more may be used, and the adjustment lens 3 is substantially orthogonal to the optical axis L. What is necessary is just to be able to move freely within the plane to perform. In this case, the temporary fixing screw holes 4 a may be formed so as to satisfy at least the number corresponding to the temporary fixing screws 10.

  In the above-described embodiment, an example in which the four fixing screws 11 are fixed has been described. However, the number of fixing screws 11 may be three, five or more. In short, the adjustment lens 3 is a plane substantially orthogonal to the optical axis L. It only needs to be fixed inside. In this case, the fixing screw holes 4 b may be formed so as to satisfy at least the number corresponding to the fixing screws 11.

  In the above-described embodiment, the lens barrel 1 having the through hole 4c formed in the lens holding frame 4 and including the adhesive 13 that fixes the adjustment lens 3 and the lens holding frame 4 has been described. The adhesive 13 may be formed or provided as necessary in consideration of the performance required for the lens barrel 1 to be created. In this case, the injection process which is a manufacturing process of the lens barrel 1 may not be performed.

  In the above-described embodiment, the injection process, which is the manufacturing process of the lens barrel 1, is performed after the fixing process, but may be performed after the temporary fixing process.

  In the above-described embodiment, the case where the temporary fixing step is performed after assembling all the lenses has been described. However, the temporary fixing step can be performed even while all the lenses are being assembled. For this reason, since the flexible alignment of the optical axis can be performed without being restricted by the order of the work steps, the manufacturing cost can be reduced.

  In the above-described embodiment, an example in which the temporary fixing screw 10 is mounted so as to face each other is shown. However, for example, a spring is formed between the adjustment lens 3 and the lens holding frame 4 so By arranging the temporary fixing screw 10 so as to be screwed in a direction against the above, the effect of the present invention can be obtained without facing the temporary fixing screw.

  In the above-described embodiment, an example in which the adjustment lens 3 is manually operated with the temporary fixing screw 10 has been described. However, temporary fixing may be automatically performed using an actuator or the like.

  Furthermore, in the above-described embodiment, the adjustment lens 3 is configured to be housed in the lens holding frame 4 that constitutes a part of the lens barrel 5, but the side surface of the adjustment lens 3 is covered with, for example, a frame or the like. However, the adjustment lens 3 is pressed and temporarily fixed through the frame using the temporary fixing screw 10, and the optical axis is aligned by fixing the adjustment lens 3 through the frame using the fixing screw 11. The adjustment lens 3 can be reliably held on the lens holding frame 4.

1 is a cross-sectional view of a lens barrel manufactured by applying a lens holding method according to an embodiment of the present invention and a camera equipped with the lens barrel. It is sectional drawing which shows the lens holding structure of the front-end | tip part of the lens barrel shown in FIG. It is sectional drawing along the III-III line | wire shown in FIG. FIG. 4 is a partially enlarged sectional view of the lens holding structure shown in FIG. 3.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Lens barrel, 3 ... Adjustment lens, 4 ... Lens holding frame, 4a ... Temporary fixing screw hole, 4b ... Fixing screw hole, 4c ... Through-hole, 5 ... Lens barrel, 10 ... Temporary fixing screw (temporary fixing Jig), 10b ... adjustment part of temporary fixing screw, 11 ... fixing screw (fixing member), 15a ... adjusting part of fixing screw, 12 ... elastic member.

Claims (2)

A lens holding method for holding a lens on a lens holding frame,
The lens is disposed in the lens holding frame, and a plurality of temporary fixing jigs for pressing the lens from a direction substantially orthogonal to the optical axis of the lens are used, and the lens is disposed in a plane substantially orthogonal to the optical axis. A temporary fixing step of moving the lens relative to the lens holding frame and temporarily fixing the lens to the lens holding frame in a state where the optical axis of the lens is aligned;
After the temporary fixing step, the lens is fixed to the lens holding frame from a direction substantially perpendicular to the optical axis of the lens by using a plurality of fixing members that press the lens from a direction substantially orthogonal to the optical axis of the lens. Fixing process to perform,
After the fixing step, the step of removing the temporary fixing jig from the lens holding frame,
Including
The temporary fixing jig is a temporary fixing screw that is screwed into a temporary fixing screw hole formed in the lens holding frame so as to penetrate in a direction substantially orthogonal to the optical axis of the lens, and the fixing member is A fixing screw that is screwed into a fixing screw hole formed in the lens holding frame so as to penetrate in a direction substantially orthogonal to the optical axis of the lens;
The lens holding method, wherein the adjustment portion of the temporary fixing screw protrudes outward from the adjustment portion of the fixing screw. After the fixing step, an adhesive is injected into the lens-side gap of the lens holding frame through a through hole formed in the lens holding frame so as to penetrate in a direction substantially orthogonal to the optical axis of the lens. The lens holding method according to claim 1, further comprising an injecting step.

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