JP2024009587A - lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel that has a smaller number of components, and includes a compact stationary lens holding structure.

SOLUTION: A lens barrel comprises: a movable lens; a lens moving frame that holds the movable lens; a stationary lens; a stationary lens frame that holds the stationary lens; a guide bar for moving the lens moving frame in a direction parallel to an optical axis; and a housing that holds the guide bar. The stationary lens frame includes a sleeve part provided with a first hole. The guide bar is inserted into the first hole to locate the stationary lens frame with respect to a direction perpendicular to the optical axis, and a first engagement part provided in the stationary lens frame is engaged with a second engagement part provided on the housing to locate the stationary lens frame with respect to a direction parallel to the optical axis.

SELECTED DRAWING: Figure 4

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a lens barrel that can be downsized.

Conventionally, means for fixing a lens frame that holds a lens to a housing uses fastening means using screws or adhesive means using adhesive application. However, in the case of fastening means using screws, costs increase due to additional parts, space is required for the screws, and the casing tends to become large. Furthermore, when an adhesive is used, there is a risk that the accuracy of holding the lens may change due to temperature contraction of the adhesive. This may particularly affect surveillance cameras installed outdoors.

Patent Document 1 discloses a configuration in which a fixed lens is held in a housing. Specifically, in the direction parallel to the optical axis, engaging parts with the lens frame are provided at three locations on the housing, and the lens frame is held by being engaged with the engaging parts. Ru.

Japanese Patent Application Publication No. 2001-66487

However, when applying the conventional technology disclosed in Patent Document 1 to a lens barrel of a surveillance camera, etc., three spaces are required for the lens frame and the housing to engage, resulting in an increase in the size of the housing. There is a risk that

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a lens barrel having a small number of parts and having a small fixed lens holding structure.

In the lens barrel,
a movable lens; a lens movement frame that holds the movable lens; a fixed lens; a fixed lens frame that holds the fixed lens; a guide bar that moves the lens movement frame in a direction parallel to the optical axis; and a guide bar that holds the guide bar. Equipped with a casing that
The fixed lens frame includes a sleeve portion having a first hole,
By inserting the guide bar into the first hole, the fixed lens frame is positioned in a direction perpendicular to the optical axis, and the first engaging portion provided on the fixed lens frame is inserted into the housing. The fixed lens frame is characterized in that the fixed lens frame is positioned in a direction parallel to the optical axis by engaging with a second engaging portion provided on the body.

According to the present invention, it is possible to provide a lens barrel with a small number of parts and a small fixed lens holding structure.

1 is a configuration diagram of a network camera that is an example of an imaging device according to an embodiment of the present invention. 1 is a functional block diagram of a camera equipped with a lens barrel 4 according to an embodiment of the present invention. FIG. 2 is a perspective view showing the internal configuration of a lens barrel 4 in an embodiment of the present invention. 3 is an exploded perspective view illustrating the peripheral structure of a fixed lens frame 32 and a housing 27. FIG. (A) to (C) are diagrams showing the structure of the fixed lens frame 32, (A) is a perspective view of the fixed lens frame 32, (B) is a front view of the fixed lens frame 32, and (C) is a fixed lens FIG. 3 is a sectional view taken along line xx of the frame 32. (A) is a perspective view of the housing 27 viewed from the subject side, (B) is a front view of the housing 27, and (C) is a y-y sectional view of the housing 27. (A) is a perspective view of the housing 27 with the fixed lens frame 32 assembled, (B) is a front view of the housing 27 with the fixed lens frame 32 assembled, and (C) is a perspective view of the housing 27 with the fixed lens frame 32 assembled. , is a sectional view taken along line zz of a state in which the fixed lens frame 32 is assembled into the housing 27. (A) is a perspective view of the housing unit 49, and (B) is a perspective view of the inside of the housing 27 of the housing unit 49.

Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following embodiments. In each figure, the same reference numerals are given to the same members or elements, and overlapping explanations are omitted or simplified.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of a network camera that is an example of an imaging device according to an embodiment of the present invention. Reference numeral 6 denotes a pan-tilt rotation unit, and the lens barrel 4 is attached to the pan-tilt rotation unit 6 with an image pickup device 5 attached to the back side of the lens barrel 4.

The pan/tilt rotation unit 6 holds the lens barrel 4 rotatably in pan, tilt, and rotation directions. The cover 2 is fastened to the pan-tilt rotation unit 6 with fastening screws 1 with the dome cover 3 sandwiched between the cover 2 and the pan-tilt rotation unit 6.

FIG. 2 is a functional block diagram of a camera equipped with a lens barrel 4 according to an embodiment of the present invention. The camera 7 captures a subject image formed through the lens barrel 4 on the image sensor 5 . The lens barrel 4 includes an aperture 8 and an aperture drive unit 9 that adjust the amount of light taken in.

Furthermore, it has zoom lenses 10 and 11 that change the zoom magnification, and a focus lens 12 that forms an image on the light receiving surface of the image sensor 5, and zoom motors 13 and 14 that drive the respective lenses, and a focus motor. It has 15.

The photographic information acquired by the image sensor 5 is transmitted to the image processing section 16, and a video signal is formed through predetermined image processing. Further, the photographing information is transmitted to the camera control section 17 and displayed on a display section 18 such as a liquid crystal display. Note that the camera control section 17 and the display section 18 may be placed in a remote controller provided separately from the imaging device. In that case, communication between the camera 7 and the camera control section 17 is performed, for example, via a wireless communication section or the Internet.

FIG. 3 is a perspective view showing the internal configuration of the lens barrel 4 in the embodiment of the present invention. The lens barrel 4 has five lens groups consisting of L1 to L5. L1 is a fixed first group lens arranged on the incident side, into which light is incident. L2 is a second group lens that moves in a direction parallel to the optical axis to perform a magnification change operation, and L3 is a third group lens that similarly performs a magnification change operation. L4 is a 4-group lens that moves in a direction parallel to the optical axis to perform a focusing operation. L5 is a fixed 5-group lens.

The fixed lens frame 19 holding the first group lens L1 is fastened and fixed to the housing 21 using four first group fixing screws 20. A lens moving frame 23 holding the lens L2 is supported by guide bars 24 and 25 so as to be movable in a direction parallel to the optical axis. Further, an aperture unit 26 is fixed to the lens moving frame 23.

The guide bars 24 and 25 are fixed between the casing 21 and the casing 27. A lens moving frame 28 holding the third group moving lens L3 is supported by guide bars 29 and 30 so as to be movable in a direction parallel to the optical axis. The guide bars 29 and 30 are also fixed between the casings 21 and 27. That is, the housing 27 holds the guide bars 29, 30, etc.

A lens moving frame 31 holding the fourth group lens L4 is supported by guide bars 29 and 30 so as to be movable in a direction parallel to the optical axis. The fixed lens frame 32 holds the fifth group lens L5. Here, the fixed lens frame 32 functions as a fixed lens frame that holds the fifth group lens L5 as a fixed lens. Details of the structure for holding the fixed lens frame 32 with respect to the housing 27 will be described later.

33 and 34 are zoom motors, which are fixed to the housing 27. The screw parts of the zoom motors 33, 34 are engaged with racks (not shown) connected to the lens moving frames 23, 28, and the rotation of the screws causes the lens moving frames 23, 28 to move in a direction parallel to the optical axis. Move to.

35 is a focus motor, which is fixed to the housing 27. A screw portion of the stepping motor engages with a rack (not shown) fixed to the lens moving frame 31, and rotation of the screw causes the lens moving frame 31 to move in a direction parallel to the optical axis. Here, for example, L3 and L4 are moving lenses, and the lens moving frame 28 and the lens moving frame 31 each function as a lens moving frame that holds a moving lens. Further, the guide bars 29 and 30 function as guide bars for moving the lens moving frame in a direction parallel to the optical axis.

A photointerrupter (not shown) is fixed to the casing 27. The same number of stepping motors are provided. The positions of the lens moving frames 23, 28, and 31 are detected and controlled by the output of the photointerrupter and the rotation speed of the stepping motor.

36 is a dummy glass, 37 is an infrared cut filter, 38 is a filter frame, and 39 is a filter switching actuator. These are sandwiched between the housing 27 and the image sensor holder 40. By moving the actuator 39 in the vertical direction in the figure, the dummy glass 36 and the infrared cut filter 37 move in a direction perpendicular to the optical axis and are switched.

Next, a structure for holding the fixed lens frame 32 with respect to the housing 27 will be explained. FIG. 4 is an exploded perspective view illustrating the peripheral structure of the fixed lens frame 32 and the housing 27. The fixed lens frame 32 is engaged with and held by the same guide bars 29 and 30 as the lens movable frames 28 and 31.

5(A) to (C) are diagrams showing the structure of the fixed lens frame 32, in which FIG. 5(A) is a perspective view of the fixed lens frame 32, (B) is a front view of the fixed lens frame 32, (C) is a sectional view taken along line xx of the fixed lens frame 32.

A first hole 41 and a second hole 42 are provided in the sleeve portion 43 of the fixed lens frame 32 so as to be able to engage with the guide bar 30 . Further, an elongated hole 44 is provided so as to engage with the guide bar 29. Therefore, the fixed lens frame 32 is movably positioned with respect to the housing 27 in a direction perpendicular to the optical axis by the guide bars 29 and 30 fixed to the housing 27.

That is, by inserting the guide bar 30 through at least the first hole 41, the fixed lens frame 32 is positioned in the direction perpendicular to the optical axis. In this embodiment, since the sleeve portion 43 has the first hole 41 and the second hole 42 through which the guide bar 30 is inserted, positioning accuracy can be improved.

Generally, when lenses L1 to L5 are tilted, the resolution performance of the lenses tends to deteriorate. However, in this embodiment, the guide bar 30 and the fixed lens frame 32 are engaged using the first hole 41 and the second hole 42, and the occurrence of collapse due to the play of the engagement is caused by the play of the through hole. It is suppressed only by the minute. In other words, the fixed lens frame 32 is prevented from falling in a direction parallel to the optical axis.

Note that the fixed lens frame 32 is provided with a recessed portion 45 as a first engaging portion between a first hole 41 and a second hole 42 provided on the side surfaces of both ends of the sleeve portion 43. This is a recessed portion for engaging with a convex portion serving as a second engaging portion provided on the casing 27, which will be described next.

6(A) is a perspective view of the casing 27 viewed from the subject side, FIG. 6(B) is a front view of the casing 27, and FIG. 6(C) is a y-y sectional view of the casing 27. The housing 27 is provided with a convex portion 46 as a second engaging portion for engaging and holding the fixed lens frame 32. By engaging the convex portion 46 of the housing 27 with the recess 45 provided in the fixed lens frame 32, the fixed lens frame 32 is held by the housing 27 in a direction parallel to the optical axis. Further, the housing 27 is provided with holes 47 and 48 for holding the guide bars 29 and 30.

7(A) is a perspective view of the housing 27 with the fixed lens frame 32 assembled, (B) is a front view of the housing 27 with the fixed lens frame 32 assembled, and (C ) is a zz cross-sectional view of the housing 27 with the fixed lens frame 32 assembled therein.

By engaging the convex portion 46 of the housing 27 and the recess 45 provided in the fixed lens frame 32, a hole 47 for holding the guide bar 29 of the housing 27 and a first hole 41 of the fixed lens frame 32, The positions of the second holes 42 substantially coincide with each other in the direction perpendicular to the optical axis, as shown in FIGS. 7(B) and 7(C). That is, by engaging the concave portion as the first engaging portion provided on the fixed lens frame with the convex portion as the second engaging portion provided on the housing, the fixed lens frame is aligned parallel to the optical axis. The position is determined in a certain direction.

In this way, by providing the recess 45 between the first hole 41 and the second hole 42 provided on the side surfaces at both ends of the sleeve portion 43, the convex portion of the housing 27 can be formed using the empty space. 46, making it possible to create a compact housing.

Further, the surface forming the recess 45 and the surface forming the projection 46 are engaged with each other in a direction perpendicular to the optical axis. Other surfaces do not need to be engaged. With this configuration, the fixed lens frame 32 is engaged with the casing 27 on the minimum necessary surfaces in the direction parallel to the optical axis, and the fixed lens can be held with a simple configuration. Further, the positions of the hole portion 48 for holding the guide bar 30 of the housing 27 and the elongated hole 44 of the fixed lens frame 32 substantially coincide with each other in the direction perpendicular to the optical axis as shown in FIG. 7(B).

With the above configuration, the fixed lens frame 32 is held by the housing 27 in directions parallel and perpendicular to the optical axis. In other words, the fixed lens frame 32 is fixed to the housing 27 without using screw fastening means. Therefore, the number of screw parts can be reduced, and the space for the screws can also be reduced, making it possible to create a compact casing.

Although this embodiment has been described in which the fixed lens frame 32 has a concave portion 45 and the housing 27 has a convex portion 46, the concave and convex shapes may be reversed. In other words, the lens fixing frame may have a convex portion, and the housing may have a concave portion.In other words, as long as the concavo-convex structure can be engaged, either is acceptable. That is, when one of the first engaging part and the second engaging part is a recessed part, the other may be a convex part that can be engaged with the recessed part.

Alternatively, instead of engaging with the convex part and the concave part, a first engaging part and a second engaging part of other engageable shapes are provided on the fixed lens frame and the housing, respectively, and the two are engaged with each other. It's okay. Further, in the present embodiment, for example, a recess 45 as a first engaging part is provided in the sleeve part 43 of the fixed lens frame 32, but the position where the first engaging part is arranged is at the position of the fixed lens frame 32. It may be located at a location other than the sleeve portion 43.

Next, the housing unit 49 will be explained. 8(A) is a perspective view of the housing unit 49, and FIG. 8(B) is a perspective view of the inside of the housing 27 of the housing unit 49. In the housing unit 49, a lens moving frame 28, a lens moving frame 31, a fixed lens frame 32, guide bars 29 and 30, a zoom motor 34, and a focus motor 35 are built into the housing 27.

Furthermore, the fixed lens frame 32 is held together with the lens movable frames 28 and 31 using a guide bar 29. In this way, by using the guide bars 29 and 30 used when the lens moving frame 28 and the lens moving frame 31 move to also position the fixed lens frame 32, the space for positioning the fixed lens frame 32 can be reduced and the size can be reduced. This makes it possible to create a new housing.

Further, the lens barrel 4 is arranged in a nested manner so that the lens moving frames 28 and 31 are held by a common guide bar 29. That is, in the example shown in FIG. 4, the rear end of the lens moving frame 28 is arranged behind the front end of the lens moving frame 31, and the lens moving frames 28 and 31 are moved along the common guide bar without interfering with each other. It can be slid. Therefore, it is possible to shorten the overall length of the lens barrel 4 and increase the moving distance of the lens moving frame.

In this embodiment, as described above, there are at least two sets of moving lenses and lens moving frames, and a part of one lens moving frame is disposed inside a part of the other lens moving frame. It has nested parts. Further, in the nested portion, a guide bar 29 is provided as a second guide bar that is inserted into the two lens movement frames.

Note that the sleeve portion 43 of the fixed lens frame 32 and the lens movable frames 28, 31 are arranged in a nested manner on opposite sides of the optical axis center. That is, the guide bar 29, which is the second guide bar, is provided on the opposite side of the optical axis to the guide bar 30 that is inserted into the first hole 41 of the fixed lens frame 32. Therefore, the fixed lens frame 32 can be efficiently arranged inside the housing 27, and the housing can be made smaller.

As described above, by engaging the convex portion 46 of the housing 27 and the concave portion 45 provided in the fixed lens frame 32, the fixed lens frame 32 is moved relative to the housing 27 in a direction parallel to the optical axis. It can be held stably.

In addition, since the fixed lens frame 32 is held in the direction perpendicular to the optical axis using the guide bars 29 and 30 when moving the lens moving frame 28 and the lens moving frame 31, the fixed lens frame 32 can be fixed without using screws or the like. The lens frame 32 can be held in the housing 27. In other words, it is possible to realize a lens barrel with a small number of parts and a small fixed lens holding structure.

Although the present invention has been described above in detail based on its preferred embodiments, the present invention is not limited to the above embodiments, and can be modified in various ways based on the spirit of the present invention. It is not excluded from the scope of the invention.

32...Fixed lens frame 41...First hole 42...Second hole 43...Sleeve portion 44...Elongated hole 45...Concave portion provided in sleeve portion 46...Convex portion of housing 27 47...Guide bar of housing 27 48...A hole in the housing 27 that holds the guide bar 30

Claims (7)

a moving lens,
a lens moving frame that holds the moving lens;
fixed lens,
a fixed lens frame that holds the fixed lens;
a guide bar for moving the lens moving frame in a direction parallel to the optical axis;
comprising a casing that holds the guide bar,
The fixed lens frame includes a sleeve portion having a first hole,
By inserting the guide bar into the first hole, the fixed lens frame is positioned in a direction perpendicular to the optical axis, and the first engaging portion provided on the fixed lens frame is inserted into the housing. A lens barrel characterized in that the fixed lens frame is positioned in a direction parallel to the optical axis by engaging with a second engaging portion provided on the body. 2. The lens barrel according to claim 1, wherein the sleeve portion has a second hole through which the guide bar is inserted together with the first hole. The lens barrel according to claim 1, wherein the first engaging portion is provided in the sleeve portion. 2. The lens barrel according to claim 1, wherein one of the first engaging part and the second engaging part is a concave part, and the other is a convex part that can be engaged with the concave part. 5. The lens barrel according to claim 4, wherein a surface forming the concave portion and a surface forming the convex portion are engaged with each other in a direction perpendicular to the optical axis. It has at least two sets of the moving lens and the lens moving frame, and has a nested portion in which a part of one of the lens moving frames is placed inside a part of the other lens moving frame. 2. The lens barrel according to claim 1, further comprising a second guide bar inserted into the two lens movement frames in the nested portion. 7. The lens according to claim 6, wherein the second guide bar is provided on the opposite side of the optical axis with respect to the guide bar that is inserted into the first hole of the fixed lens frame. Lens barrel as described.

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