JPH0921938A - Mounting structure for lens frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain structure capable of easily obtaining required torque in adjustment when a lens frame is mounted without causing focus displacement in the mounting structure of the lens frame used in a CCD board camera, etc. SOLUTION: A male screw part 13 is formed on the outer periphery of the lens frame 10, and a holding hole 21 is formed on the lens holder 20, and a female screw part 22 is formed on the inner periphery of the holding hole. Six ribs 23 extending in an axial direction are formed at the depth of the female screw part of the holding hole 21 keeping an equal angle interval. When the male screw part 13 is screwed in the female screw part 22, a screw groove is formed on the rib 23 by the male screw part 13. In such a way, the lens frame 10 is mounted on the lens holder 20 without causing play by the self- tapping of the lens frame 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens frame mounting structure, and is particularly suitable for mounting the lens frame while positioning the lens holder in the axial direction so as to obtain a prescribed focus position. The present invention relates to a mounting structure for a lens frame.

[0002]

2. Description of the Related Art Conventionally, CCDs used for monitoring devices and the like
(Charge-Coupled Device) As an optical system used in a board camera, a lens frame containing a lens may be attached to a lens holder attached to a main body having a built-in circuit board having a CCD mounted therein.

In this case, a male screw portion is formed on the mounting side of the lens frame, and a holding hole having a female screw portion corresponding to this male screw portion is provided in the lens holder. The lens frame is screwed into a holding hole formed in the lens holder, and the amount of screwing adjusts the lens frame so as to match the focus with the detection surface of the CCD. Further, the eccentric pin fitted in the lens holder may be engaged with the lens frame, and the insertion depth of the lens frame may be adjusted by rotating the eccentric pin.

In these methods, after performing focus adjustment,
The lens frame is fixed to the lens holder by screwing a screw into a fixing hole penetrating from the outer periphery of the lens holder into the holding hole and pressing the surface of the lens frame with the tip of the screw. As a method of fixing the lens frame, there is a method of elastically holding the lens frame with a wavy spring in addition to the method of fixing with the screw.

[0005]

However, in the above-described conventional lens frame mounting structure, when screwing screws to fix the lens frame with screws, the male screw of the lens frame and the lens holder are not used. Since there is play for meshing with the female screw, and when using an eccentric pin, there is play for fitting between the cylindrical portion of the lens frame and the holding hole of the lens holder. There is a problem in that the position or orientation of the frame changes and the focus position goes wrong. In addition, since the tip of the screw presses and fixes it, the posture of the lens frame may change due to vibration or impact even after the lens frame is once attached.
Care must be taken in handling after adjustment and mounting. On the other hand, when the wavy spring is used, the number of parts is increased and the wavy spring is expensive, so that the manufacturing cost is increased.

Further, in both cases of fixing with a screw and fixing with a wavy spring, since there is a dimensional play between the lens frame and the lens holder, the attitude of the lens frame is eccentric every time the lens frame is adjusted and fixed. However, it is difficult to maintain the quality of the product because variations such as inclination of the axis occur.

Further, when the lens frame is mounted on the lens holder, it is desirable that a predetermined torque be required when adjusting the introduction depth of the lens frame in order to facilitate the adjustment work. In order to generate the predetermined screw tightening torque or the eccentric pin rotation torque, particularly high processing accuracy is required, and it is very difficult to obtain the optimum adjustment torque in reality.

In view of the above problems, the present invention allows the lens frame to be attached to the lens holder with high accuracy without causing a focus shift, and the required torque for adjustment when attaching the lens frame can be easily obtained. The purpose is to realize a new lens frame mounting structure that can be used.

[0009]

Means for Solving the Problems In order to solve the above problems, the present invention has a means for mounting a cylindrical mounting portion of a lens frame accommodating a lens in a holding hole having a circular cross section formed in a lens holder. In a lens frame mounting structure configured to be mounted, a male screw portion is formed on an outer peripheral surface of the mounting portion, and a male screw portion of the mounting portion is screwed on an outer opening side of an inner peripheral surface of the holding hole. A mating female screw portion is formed, and a plurality of ribs extending in the axial direction of the lens frame are formed on the inner side of the inner peripheral surface so as to be self-tapping by the male screw portion.

Further, in a lens frame mounting structure configured to mount a cylindrical mounting portion of a lens frame accommodating a lens in a holding hole having a circular cross section formed in a lens holder, an outer peripheral surface of the mounting portion. A male screw portion is formed on the inner peripheral surface of the holding hole, and a plurality of ribs extending in the axial direction of the lens frame are formed on the inner peripheral surface of the holding hole so as to be self-tapping by the male screw portion. And / or on the outer opening side of the holding hole, a guide portion that is substantially fitted to the outer opening side of the holding hole and / or to the tip end side of the mounting portion is formed. To do.

In these cases, it is preferable that the ribs are formed in the same shape and are formed at equal angular intervals on the inner peripheral surface of the holding hole.

Further, it is preferable that the cross-sectional area of the rib is gradually reduced in the introduction direction of the lens frame.

Further, it is preferable that a portion in which the cross-sectional area of the rib is gradually increased in the introduction direction of the lens frame is provided at least within a predetermined range from the end of the rib on the side of the external opening.

[0014]

According to the present invention, the male screw portion formed in the mounting portion of the lens frame is screwed into the female screw portion formed in the holding hole of the lens holder, and the tip of the male screw portion is formed in the back. When the rib continues to be screwed in after contacting the rib, the rib is tapped by the male screw portion, and the lens frame is attached to the lens holder by self-tapping without play.

At this time, when tapping the male screw portion and the rib, the male screw portion and the female screw portion are preliminarily screwed with each other, so that the position and the posture of the lens frame are regulated to some extent by fitting the both screw threads. Therefore, it is possible to prevent the axis line of the lens frame from being tilted and from being misaligned.

The rotation resistance when the lens frame is introduced is the cutting resistance required for tapping between the male thread portion and the thread formed on the rib by self-tapping or the male thread portion and the thread. It is generated by the frictional resistance caused by sliding, and the rotational resistance when pulling out the lens frame is generated by the frictional resistance caused by the sliding between the male screw part and the thread, so focus adjustment by adjusting the lens frame introduction depth. Since a predetermined rotation torque is required for work and adjustment of a minute amount is relatively easy, the workability of focus adjustment can be improved. The rotation torque required for rotation between the lens frame and the lens holder or the holding and fixing force for fixing the two can be appropriately adjusted by the number of ribs, width, height, cross-sectional area and the like.

Therefore, while the position and orientation of the lens frame are maintained, a mounting structure can be obtained by screwing the male screw portion and the rib, which are formed without play by self-tapping, so that the axis of the lens frame can be tilted and It is possible to prevent misalignment, facilitate focus adjustment, and prevent focus deviation when fixing the lens frame due to the contact structure by self-tapping. realizable.

According to the second aspect of the present invention, when tapping the male screw portion and the rib, the lens frame and the lens holder are fitted with each other by the guide portion formed in advance on either or both of the lens frame and the lens holder. Therefore, the position and the posture of the lens frame are regulated to some extent by the fitting of the both, and the inclination of the axis of the lens frame and the misalignment can be prevented.

According to the third aspect of the present invention, the ribs are formed in the same shape and are formed at equal angular intervals on the inner peripheral surface of the holding hole, so that the male screw portion is evenly stressed from a plurality of peripheral ribs. Therefore, the inclination of the axis of the lens frame and the misalignment can be prevented.

According to the fourth aspect, by gradually reducing the cross-sectional area of the rib in the introduction direction of the lens frame, as the lens frame is screwed in, the tapping region increases and the rotational resistance increases. Since the required resistance at the tip end due to tapping is gradually reduced, it is possible to reduce the rate of increase in rotational resistance, reduce the fluctuation in rotational torque required for focus adjustment, and improve the workability of focus adjustment. it can.

According to the fifth aspect, the male screw portion is provided by providing a portion where the cross-sectional area of the rib is gradually increased in the introduction direction of the lens frame at least within a predetermined range from the end portion of the rib on the side of the external opening. Since it is possible to gradually increase the tapping amount, it is possible to prevent the axis line of the lens frame from falling and misalignment, particularly at the start of self-tapping, and to mount the lens frame with high accuracy.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a lens frame mounting structure according to the present invention will be described below with reference to the accompanying drawings. In each of the embodiments described below, a lens holder attached to the body of the CCD board camera (whether configured as a separate body attached to the camera body, is integrated into the camera body (or casing)). However, the present invention is not limited to these examples, and is applicable to a wide range of general lens frame mounting structures.

[First Embodiment] FIG. 1 is a vertical sectional view showing the overall structure of the first embodiment, and FIG. 2 shows the present embodiment in FIG.
It is a cross-sectional view showing a state of being cut along the line II-II.
The present embodiment is a lens frame mounting structure formed on the lens frame 10 and the lens holder 20.

The lens frame 10 includes a lens 11 and a lens 1.
2 is housed inside, and a male screw portion 13 is formed on the outer periphery of the lens 12 side. On the other hand, a holding hole 21 is formed in the lens holder 20, and the holding hole 21
A female screw portion 22 is formed on the inner surface of the outer opening 20a side. On the inner surface of the holding hole 21 on the inner opening 20b side,
Six ribs 23 extending in the axial direction of the holding hole 21 are formed following the female screw portion 22 or at predetermined intervals. The rib 23 has a holding hole 21 as shown in FIG.
Are formed at equal angular intervals on the inner peripheral surface of the.

The rib 23 projects from the surface of the holding hole 21 having an inner diameter larger than the outer diameter of the male screw portion 13 of the lens frame 10 (the diameter of the virtual cylinder contacting the crest of the screw thread), and the male screw is formed. It is formed to have an apex portion smaller than the outer diameter of the portion 13 and having an inner diameter larger than the diameter of the valley of the male screw portion 13 so as to match the virtual cylindrical surface. Rib 23 shown in FIG.
Has an arcuate surface having a substantially semicircular cross section, but ribs having various shapes such as one having an elliptic arc surface, one having a triangular cross section or a trapezoidal cross section may be formed. However, in order to accurately position the center position of the lens frame 10 to be described later and to prevent the axial line of the lens frame 10 from falling, it is preferable that the width of the rib be gradually reduced from the base portion to the top portion.

In this embodiment having such a structure, the lens frame 10 is made of a material harder than the lens holder 20. For example, the lens frame 10 is formed of a hard resin such as polycarbonate resin or liquid crystal polymer, and the lens holder 20 is formed of a relatively soft resin such as ABS resin by injection molding. In this case, the material of the lens frame 10 is most preferably a polycarbonate resin mixed with glass fiber. Further, the lens frame 10 may be made of metal such as aluminum alloy or brass, and the lens holder 20 may be made of polycarbonate or other resin.

When the male screw portion 13 of the lens frame 10 is screwed into the female screw portion 22 of the lens holder 20 and screwed in,
The tip of the male screw portion 13 passes through the female screw portion 22 and enters the portion where the rib 23 is formed, and the male screw portion 13 cuts a screw groove in the rib 23. By self-tapping by the male screw portion 13 of the lens frame 10, the lens frame 10 is introduced into the holding hole 21 in a state of being in close contact with the lens holder 20.

Focus adjustment is performed by screwing the lens frame 10 into the lens holder 20 and moving the lens frame 1 to the detection position F of the CCD.
It is performed so that the focus of the zero lens group may be matched. At this time, a cutting resistance is generated when the ribs 23 are engraved with screws by self-tapping, and the male screw portion 13 and the ribs 23 are self-tapping and screwed together with almost no play. When the lens frame 10 is rotated, a required sliding resistance is inevitably received. The cutting resistance almost disappears after the rib 23 is once threaded, but the sliding resistance always occurs regardless of the position of the lens frame or the rotation direction.

When adjusting the focus, the cutting resistance and / or
Alternatively, a certain amount of rotation torque is required to change the introduction depth of the lens frame 10 due to the sliding resistance, and this rotation torque facilitates fine position adjustment, and facilitates focus adjustment work, The focus position is maintained after adjustment.

When the lens frame 10 is screwed in, self-tapping is performed while applying a predetermined axial pressure to the lens frame 10, so that the male screw portion 13 and the female screw portion 22.
Even if there is a play between and, the screw thread of the male screw part 13 is fixed in a state of being pressed against the screw thread of the female screw part 22 from above. Therefore, sliding resistance between the male screw portion 13 and the female screw portion 22 is also generated, which results in further increasing the fixing force of the lens frame 10. If it is not necessary to adjust the position of the lens frame 10 again after adjusting the focus once, the lens frame 1
A fixing means such as pouring an adhesive may be separately provided in the threaded portion between the 0 and the holding hole 21.

In this embodiment, as shown in FIG. 2, since the six ribs 23 have the same shape and are formed at equal angular intervals, the male screw portion 13 of the lens frame 10 and the holding hole are formed. Even if there is some play between the female threaded portion 21 and the female threaded portion 21, when the tip of the male threaded portion 13 enters the area where the rib 23 is formed, the surrounding ribs 23 uniformly receive pressure, so In the initial stage when tapping starts,
The lens frame 10 is automatically centered. Further, even during the subsequent tapping, the ribs 23 formed at equal angular intervals act almost uniformly from the surroundings, so that the center position of the lens frame 10 is continuously maintained,
The occurrence of inclination of the axis of the lens frame 10 is also prevented.

In this embodiment, the ribs 23 are provided on the inner peripheral surface of the holding hole 21 and the ribs 23 are threaded. Therefore, the number, width, height, etc. of the ribs 23 are adjusted. With this structure, it is possible to obtain an appropriate rotation resistance or a holding force for holding the lens frame position. The number of ribs 23 is
Any number may be provided as long as a plurality is provided, but it is more preferable to provide three or more in order to prevent inclination and misalignment of the lens frame.

Further, as long as the rib extends in the axial direction of the holding hole, even if the rib is formed obliquely with respect to the axial line,
A spiral rib may be used. Further, the rib 23 which is in the middle of the axial direction may disappear, and another rib may be generated from this position at a different angular position.

[Second Embodiment] Next, FIG. 3 shows a structure of a second embodiment according to the present invention. FIG. 3A shows the first pattern of this embodiment, and FIG. 3B shows the second pattern of this embodiment. 3A shows a plurality of ribs 24 formed on the inner peripheral surface of the holding hole 21 and having a width gradually decreasing toward the introduction direction of the lens frame 10 similar to that shown in FIG. is there. On the other hand, as shown in FIG. 3B, a plurality of ribs 25 whose height gradually decreases toward the introduction direction of the lens frame are formed.

By gradually reducing the width or height of the ribs, that is, the cross-sectional area of the ribs in this way, the male screw portion of the lens frame is sequentially tapped by the self-tapping holes 2.
As it goes inside 1, the screw groove cut into the rib becomes shorter or shallower as it goes deeper in the holding hole 21, so that the rotational resistance during tapping and sliding can be reduced. Therefore, generally, the rotational torque required to rotate the lens frame tends to increase as the lens frame is deeply introduced, but in the present embodiment, such an increase rate of the rotational torque can be suppressed.

Here, in the present embodiment, the width or height of the rib is changed, but the cross-sectional shape of the rib is changed by changing both, and as a result, the cross-sectional area of the rib is gradually reduced. The same action as above can be obtained. The effect of suppressing the increase of the rotational torque due to the introduction depth of the lens frame brings about an effect that the focus adjustment work can be performed under substantially the same torque condition in a wide range of the introduction depth of the lens frame.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIG. In this embodiment, FIG.
As shown in (a), the rib 26 formed on the inner peripheral surface of the holding hole 21 is formed low on the female screw portion 22 side, and gradually becomes higher toward the internal opening 20b side.
Further, as shown in FIG. 4B, the inclined portion 27a is formed so as to gradually increase from the female screw portion 22 side toward the inner opening 20b side to a predetermined distance, and thereafter, from the boundary position B to the same height. Alternatively, the contoured portion 27b may be formed.
In this case, the rib on the side of the external opening 20a is provided with an inclined portion having a large inclination angle, and the rib portion at the back of the holding hole 21 is provided with a portion having a small inclination angle or an inclined portion opposite to the inclined portion, instead of the inclined portion. It may be provided.

As described above, by providing the sloping portion of which the height gradually increases in at least a predetermined range on the female screw portion 22 side of the rib or the external opening 20a side, the tip of the male screw portion of the lens frame is attached to the female holder 20. When advancing from the screw portion 22 to the rib formation region, it is possible to gradually increase the tapping amount rather than generating a large tapping amount (amount proportional to the cross-sectional area for forming the screw groove) at a time. It is possible to prevent tilting and misalignment of the lens frame.

Although the height of the rib is changed in this embodiment, the width of the rib may be changed instead of the height in that the tapping amount can be gradually increased. Good. Further, even if both the width and the height are changed or the cross-sectional shape of the rib is changed, if the cross-sectional area of the rib is gradually increased, the same effect as that of the above embodiment can be obtained. .

[Fourth Embodiment] Next, the structure of a fourth embodiment according to the present invention will be described with reference to FIG. This example is
The point that it is composed of the lens frame 30 and the lens holder 40 is the same as in each of the above-described embodiments. However, the lens frame 30 has a cylindrical outer surface portion 34 of a predetermined length on the front end side of the male screw portion 33.
Is different. The outer peripheral surface of the cylindrical outer surface portion 34 is a smooth surface with no screws engraved, and the leading end is preferably chamfered to reduce the diameter, or the leading end corner portion is formed into a curved surface. 34a is formed.

On the other hand, the lens holder 40 has a holding hole 4
1 is formed, and a rib 42 similar to that of the above-described embodiment is formed in the holding hole 41. In this embodiment, the female screw portion formed in the previous embodiment is not formed, and six ribs 42 of the same shape are formed at equal angular intervals from the outer opening 40a to the inner opening 40b. Has been done.

In this embodiment, the outer diameter of the cylindrical outer surface portion 34 formed at the tip of the lens frame 30 is formed so as to fit exactly to the apex of the rib 42 inside the holding hole 41 of the lens holder 40. There is. Therefore, first, when the cylindrical outer surface portion 34 of the lens frame 30 is introduced into the holding hole 41 from the outer opening 40a, the lens outer frame portion 34 of the lens frame 30 is guided by the apexes of the six ribs 42. It is inserted with the inclination and misalignment prevented to some extent.

When the lens frame 30 is rotated while being pressed in this state, the cylindrical outer surface portion 34 is guided by the ribs 42 to maintain its position and posture, and the lens frame 30 taps the ribs 42 to move inside. It proceeds toward the opening 40b. After that, the focus adjustment work is performed by adjusting the introduction depth of the lens frame 30 as in the above-described embodiments.

In this embodiment, the holding hole 4 of the lens holder is
Since only the plurality of ribs 42 are formed on the inner peripheral surface of No. 1 and the cylindrical outer surface portion 34 is formed at the tip of the lens frame 30, on the other hand, self-tapping is suddenly performed at the start of screwing of the lens frame. Before that, the cylindrical outer surface portion 34 and the rib 42 are
Since the apex of the lens is fitted, the fitting guides the lens frame and prevents the lens frame from tilting or being misaligned. Therefore, despite the difference in structure, substantially the same effects as those of the first to third embodiments are achieved.

In this embodiment, the cylindrical outer surface portion 34 and the rib 42 are
The lens frame is guided by fitting with the holding hole 41 formed with, and as a result, the posture of the lens frame can be held before and during tapping.
Unlike the above-described embodiment, the fitting structure having such a guide function is set so as to be fitted to the male screw portion 33 of the lens frame on the side of the outer opening 40a of the holding hole 41 of the lens holder 40. A cylindrical inner surface portion having an inner diameter may be provided, or a cylindrical outer surface portion similar to the cylindrical outer surface portion 34 may be provided at the distal end portion of the lens frame 30, while the lens holder 40 has a holding hole 41 on the outer opening 40a side. It is also conceivable to provide the inner surface of the cylinder that fits the outer surface of the cylinder, and these structures also have the same effect as the above embodiment.

[0046]

As described above, according to the present invention, the mounting structure is formed by screwing the male screw portion and the rib, which are formed without play by self-tapping, while the position and posture of the lens frame are maintained. Since it can be obtained, it is possible to prevent the axis of the lens frame from being tilted or misaligned, and the focus adjustment becomes easy,
In addition, since the focal shift when fixing the lens frame can be prevented due to the contact structure by self-tapping, it is possible to realize the mounting structure of the lens frame in which the focus is adjusted with high accuracy.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a structure of a first embodiment according to the present invention.

FIG. 2 is a transverse cross-sectional view showing a state of the first embodiment taken along line II-II in FIG.

FIG. 3 is vertical sectional views (a) and (b) showing two structural examples of a second embodiment according to the present invention.

FIG. 4 is longitudinal sectional views (a) and (b) respectively showing two structural examples of the third embodiment according to the present invention.

FIG. 5 is a vertical sectional view showing the structure of the fourth embodiment according to the present invention.

[Explanation of symbols]

 10 lens frame 13 male screw part 20 lens holder 20a external opening 20b internal opening 21 holding hole 22 female screw part 23, 24, 25, 26, 27, 42 rib 27a inclined part 34 cylindrical outer surface part (guide part)

Claims (5)

[Claims] 1. A lens frame mounting structure configured to mount a cylindrical mounting portion of a lens frame accommodating a lens into a holding hole having a circular cross section formed in a lens holder, wherein an outer peripheral surface of the mounting portion. A male screw portion is formed on the inner peripheral surface of the holding hole, and a female screw portion that is screwed into the male screw portion of the mounting portion is formed on the outer opening side of the inner peripheral surface of the holding hole. A lens frame mounting structure, wherein a plurality of ribs extending in the axial direction of the lens frame are formed by the male screw portion so as to be self-tapping. 2. A lens frame mounting structure configured to mount a cylindrical mounting portion of a lens frame accommodating a lens into a holding hole having a circular cross section formed in a lens holder, wherein an outer peripheral surface of the mounting portion. A male screw portion is formed on the inner peripheral surface of the holding hole, and a plurality of ribs extending in the axial direction of the lens frame are formed on the inner peripheral surface of the holding hole so as to be self-tapping by the male screw portion. And / or on the outer opening side of the holding hole, a guide portion that is substantially fitted to the outer opening side of the holding hole and / or to the tip end side of the mounting portion is formed. Mounting structure for the lens frame. 3. The lens frame according to claim 1, wherein the ribs are formed in the same shape and are formed at equal angular intervals on the inner peripheral surface of the holding hole. Mounting structure. 4. The mounting structure for a lens frame according to claim 1, wherein a cross-sectional area of the rib is gradually reduced in a direction of introducing the lens frame. 5. The portion according to claim 1 or 2, wherein the rib has a cross-sectional area gradually increased in the introduction direction of the lens frame within at least a predetermined range from an end of the rib on the side of the external opening. Lens frame mounting structure characterized by