JPH0734406U - Lens barrel fixing mechanism - Google Patents

Abstract

(57) [Summary] [Object] To provide a lens barrel fixing mechanism capable of fixing a lens barrel without tilting the optical axis of the lens barrel. [Structure] Cylindrical barrel 5 in which lenses 6 to 9 are housed and fixed
Is fitted in a cylindrical fitting portion 3 formed in front of the housing 1 so as to be slidable back and forth. A pair of protrusions 19 and 20 are formed on the outer surface of the front end of the fitting portion 3, and a notch 21 is formed at a position between the protrusions 19 and 20 of the fitting portion 3. Then, by bringing the projections 19 and 20 close to each other with the screw 25, the length of the circumference of the fitting portion 3 is contracted,
As a result, the inner cross-sectional area of the fitting portion 3 contracts, and the lens barrel 5
Is firmly held and fixed by the fitting portion 3. When fixing the lens barrel 5 to the fitting portion 3, extra moment or force is applied.
Lens 6 to 9 on the image plane 4 in the housing 1.
It is possible to securely fix the lens barrel 5 at the position where the image is formed in.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a lens barrel fixing mechanism, and more particularly to a lens barrel fixing mechanism capable of reliably fixing a lens barrel at a desired position.

[0002]

[Prior art]

 FIG. 4 is a side sectional view schematically showing a conventional lens barrel fixing mechanism applied to a CCD camera. In the figure, reference numeral 1 indicates a housing of the CCD camera. The housing 1 is made of resin, and has a box-shaped light receiving and converting unit 2 and a cylindrical fitting unit 3 protruding forward (to the left in the drawing). The spaces provided inside the light receiving conversion unit 2 and the fitting unit 3 communicate with each other, and light can pass through these spaces.

Inside the light receiving conversion section 2, a light receiving element which is a CCD element (not shown) is arranged. This light receiving element is arranged on the image plane 4 indicated by a virtual line orthogonal to the central axis of the fitting portion 3. This light receiving element is an element capable of photoelectric conversion, is fixed to a substrate (not shown) provided behind the image plane 4, and is electrically connected to a circuit on the substrate.

A resin-made cylindrical lens barrel 5 is fitted into the fitting portion 3 from the front so that it can slide back and forth when not fixed. A concave lens 6 and convex lenses 7, 8 and 9 are housed inside the lens barrel 5 and fixed thereto. Here, the optical axes of the concave lens 6 and the convex lenses 7, 8 and 9 coincide with the central axis of the lens barrel 5. A slit 10 is formed in the front end portion of the fitting portion 3 along the axial direction of the fitting portion 3, and a backing plate 11 covering the slit 10 is arranged in contact with the outer peripheral surface of the fitting portion 3. There is. A through hole 12 is formed in the contact plate 11. A protrusion 13 is formed on the outer peripheral surface near the rear end of the lens barrel 5 and is fitted into the slit 10. A screw hole 14 is formed from the protrusion 13 along the radial direction of the lens barrel 5. Has been done. Then, the male screw portion 15 a of the screw 15 is passed through the through hole 12 and screwed into the screw hole 14, whereby the lens barrel 5 is fixed to the fitting portion 3.

As described above, since the lens barrel 5 can be moved back and forth before being fixed, the position of the above-mentioned light receiving element, that is, the position of the image forming surface 4 is deviated due to a component mounting error or the like. Even in this case, the concave lens 6 and the convex lenses 7, 8 and 9 fixed inside the lens barrel 5 can form an image on the image plane 4. By screwing the screw 15 into the screw hole 14, the lens barrel 5 is fixed by the screw 15 at this position.

[0006]

[Problems to be solved by the device]

 By the way, in this lens barrel fixing mechanism, as described above, the slit 10 and the protrusion 13 fitted therein are provided, and the screw hole 14 is bored from the protrusion 13. And, as shown in the figure, the effective thread portion of the screw hole 14 is almost within the range of the wall thickness of the protrusion 13. This is because the lens barrel 5 is made thin so as to meet the recent demand for miniaturization of the camera. That is, if the lens barrel 5 is made thick, it is possible to provide the effective threaded portion of the screw hole 14 in the lens barrel 5 without providing the protrusion 13, but in order to downsize the lens barrel 5, the lens barrel 5 is made thin. Then, in order to make the effective screw portion of the screw hole 14 sufficiently large, the protrusion 13 must be provided on the outer peripheral surface of the lens barrel 5, and the effective screw portion must be accommodated therein.

When the protrusion 13 is provided in this way, the slit 10 is formed in the fitting portion 3 so that the inner peripheral surface of the fitting portion 3 and the outer peripheral surface of the lens barrel 5 are in close contact with each other as much as possible. There is a need to. Here, the front end of the slit 10 (the end on the left side in the drawing) needs to be open so as to receive the ridge 13 when the lens barrel 5 is fitted into the fitting portion 3 from the front.

In this lens barrel fixing mechanism, when the fitting portion 3 and the lens barrel 5 are fastened with the screw 15, the lens barrel 5 is lifted by the screw 15. Since the front end of the slit 10 is open as described above, in the position in front of the slit 10, the upper part of the outer peripheral surface of the lens barrel 5 in the drawing is the inner peripheral surface of the fitting part 3. Will not come into contact with, and the force against this lifting force is weak. Therefore, the balance is lost, and a moment is generated in the lens barrel 5 in the clockwise direction in the figure, that is, as indicated by the arrow, with the front end portion of the fitting portion 3 as the center.

Therefore, even if the lens barrel 5 is fixed at a desired position, the lens barrel 5 slightly tilts in the direction indicated by the arrow, and the optical axis of the lens barrel 5 deviates from the central axis of the fitting portion 3. However, there is a problem that the focal point F is displaced downward from the center point of the image plane 4 as shown in the figure. At this time, the rear end portion below the lens barrel 5 and the portion of the fitting portion 3 that abuts here are elastically deformed, but both the fitting portion 3 and the lens barrel 5 are made of resin. In this case, the amount of displacement is larger than that of metal, and thus the shift of the focus F is also large.

Further, even though the lens barrel 5 is fitted into the fitting portion 3 as described above, when the fitting portion 3 and the lens barrel 5 are fastened together, the circumference of the axis line given to the screw 15 is provided. The lens barrel 5 rotates around the screw 15 and tilts due to the moment, the optical axes of the lenses 6 to 9 are displaced in the vertical direction of the paper surface, and the focus F is perpendicular to the paper surface from the center of the image forming surface 4. It shifts in the direction. Further, if it is attempted to suppress the rotation of the lens barrel 5 around the screw 15, an extra force is applied to the lens barrel 5 or the fitting portion 3, and the lenses 6 to 9 form an image. An image may be formed in front of or behind the surface 4. For the above reasons, it is extremely difficult to fix the lens barrel 5 while suppressing the deviation and inclination of the optical axis with the conventional fixing mechanism by screwing even if the image can be formed on the image forming surface 4. there were.

The present invention has been made in consideration of such circumstances, and a lens barrel fixing mechanism capable of fixing the lens barrel at a desired position without displacement and inclination of the optical axis. The purpose is to provide.

[0012]

[Means for Solving the Problems]

 The lens barrel fixing mechanism according to the present invention is a lens barrel fixing mechanism in which a lens barrel in which a lens is housed and fixed is fitted in a cylindrical fitting portion provided in a housing. It is characterized in that a contracting means for contracting the cross-sectional area is provided so that the lens barrel can be fixed in the fitting portion.

Here, the contracting means includes a pair of protrusions provided on the outer surface of the fitting portion, a notch formed between the pair of protrusions of the fitting portion, and a proximity means for bringing the pair of protrusions close to each other. May be provided. Here, the proximity means may be a screw. In addition, the notch is formed so as to extend from the end of the fitting part to the rear of the protrusion, and the rear part of the notch, which is behind the protrusion, is made wider, reducing the force that brings the protrusions closer together. You may do it.

[0014]

[Action]

 The lens barrel in which the lens is housed and fixed can be fixed at a desired position in the fitting portion. The shrinking means shrinks the cross-sectional area inside the fitting part, and the shrinking action tightens the lens barrel around the entire circumference by the shrinking action, so that the tilt of the optical axis of the lens barrel and the deviation from the center axis are prevented. It is possible to prevent it and fix the lens barrel by holding it more firmly. Here, the pair of protrusions arranged with the groove formed in the fitting portion interposed therebetween can be brought close to each other by a proximity means such as a screw. In this case, the width of the groove is narrowed, and the cross-sectional area of the fitting portion can be easily contracted. Further, by widening the rear portion of the notch, it is possible to reduce the force for bringing the protrusions closer to each other.

[0015]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a side sectional view of a CCD camera to which the lens barrel fixing mechanism according to the embodiment is applied, FIG. 2 is a sectional view taken along the line II--II in FIG. 1, and FIG. It is a bottom view showing the contracting means. In the following description, the same components as those of the above-described conventional technique are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 1, also in this embodiment, the resin-made cylindrical lens barrel 5 is fitted in the cylindrical-shaped fitting portion 3 of the resin-made casing 1 so as to be slidable back and forth. Has been done. Tongues 16 are provided so as to be flush with each other on the inner peripheral surface of the light receiving and converting unit 2 of the housing 1, and a printed circuit board 17 is screwed to the back of the tongues 16. A frame portion 18 is fixed to a front portion of the printed circuit board 17 where the circuit is not formed. The above-mentioned CCD element E is arranged inside the frame portion 18, whereby the image forming surface 4 is provided. The CCD element E is connected to a circuit (not shown) formed on the printed circuit board 17, whereby the photoelectric output from the CCD element E is supplied to the circuit.

As shown in FIG. 2 and FIG. 3, a pair of rectangular plate-shaped projections 19 and 20 on the same cross section are provided on the lower side of the front end of the fitting portion 3 so as to project outward. ing. Further, the fitting portion 3 is formed with a notch 21 along the central axis thereof. The notch 21 is formed to have a narrow width at a position between the protrusions 19 and 20, and is formed to be wide at a rear portion 22 at a position behind the protrusion 19, thereby forming an L-shape. ing. That is, the rear portion 22 is formed so as to be only behind the protrusion 19.

A through hole 23 penetrating in the thickness direction is formed in the protrusion 19, while a screw hole 24 penetrating in the thickness direction is formed in the protrusion 20 at a position corresponding to the through hole 23. ing. Then, the male screw portion 25a of the screw 25 is passed through the through hole 23 and screwed into the screw hole 24 to bring the projections 19 and 20 close to each other. As a result, the cross-sectional area inside the fitting portion 3 contracts, and the lens barrel 5 is fixed to the fitting portion 3. That is, since the notch 22 is formed at the front end of the fitting portion 3, the length of the circumference of the fitting portion 3 can be expanded and contracted, and the screw 25 is screwed into the screw hole 24 to project the projections 19, 20. It is possible to shrink the length of the circumference of the fitting part 3 by bringing the two close to each other. Here, the screw 25 and the screw hole 24 constitute a proximity means for bringing the projections 19 and 20 close to each other, and the proximity means, the notch 21 and the projections 19 and 20 contract the cross-sectional area inside the fitting portion 3. It constitutes the contracting means.

Since the present embodiment has the above-described configuration, the lens barrel 5 is fitted into the fitting portion 3, and the lens barrel 5 is moved to the position where the lenses 6 to 9 are imaged on the image plane 4. At the time of fixing, the stress due to the fastening force of the screw 25 is only applied to the circumference of the fitting portion 3, and no extra moment is applied to the lens barrel 5. Therefore, even if both the fitting portion 3 and the lens barrel 5 are made of resin to be thin as in the present embodiment, it is possible to prevent the lens barrel 5 from being tilted during fixing. Since the optical axis of 5 does not deviate from the central axis of the fitting portion 3, the focus F can be kept at the center point of the image plane 4. Further, in order to suppress the tilt of the lens barrel 5, it is not necessary to apply an extra force to the fitting portion 3 or the lens barrel 5, so that the lens barrel 5 does not move during fixing, and the lens 6 9 to 9 are reliably imaged on the image plane 4. As described above, in the lens barrel fixing mechanism of this embodiment, if the lens barrel 5 is moved back and forth to form an image on the image forming surface 4, the lens barrel 5 can be securely fixed at that position.

Further, since the rear portion 22 of the notch 21 behind the projection 19 is wide, the bending elasticity in the vicinity of the projection 19 can be increased, so that the force for bringing the projections 19 and 20 close to each other can be reduced. It is possible to Further, the stress generated at this time is less likely to propagate to the rear side of the rear portion 22 of the fitting portion 3, and the stress is evenly applied to the circumference of the front end portion of the fitting portion 3. . Therefore, the fitting portion 3 can stably hold the lens barrel 5 with this uniform stress. In addition, in the present embodiment, the rear portion 22 is formed only behind the protrusion 19, but the present invention is not limited to this, and the rear portion 22 may be formed behind the protrusion 20. . Further, the rear portion 22 may be formed so as to be behind both the projections 19 and 20.

[0021]

As is apparent from the above description, according to the lens barrel fixing mechanism of the present invention, the cross-sectional area of the inner side of the fitting portion into which the lens barrel is fitted is contracted, so that the lens barrel Since the lens is fixed inside the fitting part, no extra moment is applied to the lens barrel. Therefore, even if both the fitting part and the lens barrel are thinly made of resin, it is possible to prevent the tilting of the lens barrel when fixing, and the optical axis of the lens barrel is the central axis of the fitting part. Since it does not deviate, the focus of the lens can be kept at the center point of the image plane. Moreover, in order to suppress the tilt of the lens barrel, it is not necessary to apply an extra force to the fitting part or the lens barrel, so the lens barrel does not move during fixing, and the lens is reliably imaged. The image is formed on the surface.

Further, the contracting means for contracting the fitting portion is a proximity means for bringing the pair of protrusions and the notch formed between the protrusions and the protrusions close to each other, thereby simplifying the configuration and reducing the number of parts and the cost associated therewith. It is possible to suppress the rise. This effect is more preferably exhibited by using a screw as the proximity means. Further, by widening the rear portion of the notch, it is possible to reduce the force for bringing the protrusions close to each other.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a CCD camera to which a lens barrel fixing mechanism according to an embodiment of the present invention is applied.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a bottom view showing contracting means of a fitting portion in the lens barrel fixing mechanism of the embodiment.

FIG. 4 is a side sectional view showing an outline of a conventional lens barrel fixing mechanism applied to a CCD camera.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 3 Fitting part 4 Image plane 5 Lens barrel 6-9 Lens 19,20 Protrusion 21 Notch 22 Rear part 24 Screw hole 25 Screw

Claims (4)

[Scope of utility model registration request] 1. A lens barrel in which a lens is housed and fixed,
In a lens barrel fixing mechanism that fits in a tubular fitting portion provided in a housing, a shrinking unit that shrinks a cross-sectional area of the inside of the fitting portion is provided to move the lens barrel in the fitting portion. The lens barrel fixing mechanism is characterized in that it can be fixed with. 2. The contraction means includes a pair of protrusions provided on an outer surface of the fitting portion, a notch formed between the pair of protrusions of the fitting portion, and the pair of protrusions. The lens barrel fixing mechanism according to claim 1, further comprising a proximity unit for bringing the lens barrel into proximity. 3. The lens barrel fixing mechanism according to claim 2, wherein the proximity means is a screw. 4. The notch is formed so as to extend from the end of the fitting portion to the rear of the protrusion, and the rear portion of the notch, which is behind the protrusion, is widened. The lens barrel fixing mechanism according to claim 2 or 3, wherein a force for bringing the protrusions close to each other is reduced.